Title of Invention

HIGH-CLEANING SILICA MATERIALS AND DENTIFRICE CONTAINING SUCH

Abstract Unique abrasive and/or thickening materials that are in situ generated compositions of precipitated silicas and silica gels are provided. Such compositions exhibit different beneficial characteristics depending on the structure of the composite in situ generated material. With low structured composites (as measured via linseed oil absorption levels from 40 to 100 ml oil absorbed/100 g composite), simultaneously high pellicle film cleaning properties and moderate dentin abrasion levels are possible in order to accord the user a dentifrice that effectively cleans tooth surfaces without detrimentally abrading such surfaces. Increased amounts of high structure composite materials tend to accord greater viscosity build and thickening benefits together with such desirable abrasion and cleaning properties, albeit to a lesser extent than for the low structure types. Thus, mid-range cleaning materials will exhibit oil absorption levels from an excess of 100 to 150, and high thickening/low abrasion composite exhibit oil absorption properties in excess of 150. Such an in situ, simultaneously produced precipitated silica/silica gel combination provides such unexpectedly effective low abrasion and high cleaning capability and different thickening characteristics as compared to physical mixtures of such components. A method for making such gel/precipitated silica composite materials is also disclosed.
Full Text Field of the Invention
This invention relates to unique abrasive and/or thickening materials that are in
situ generated compositions of precipitated silicas and silica gels. Such compositions
exhibit different beneficial characteristics depending on the structure of the composite in
situ generated material. With low structured composites (as measured via linseed oil
absorption levels from 40 to 100 ml oil absorbed/100g composite), simultaneously high
pellicle film cleaning properties and moderate dentin abrasion levels are possible in order
to accord the user a dentifrice that effectively cleans tooth surfaces without detrimentally
abrading such surfaces. Increased amounts of high structure composite materials tend to
accord greater viscosity build and thickening benefits together with such desirable
abrasion and cleaning properties, albeit to a lesser extent than for the low structure types.
Thus, mid-range cleaning materials will exhibit oil absorption levels from an excess of
100 to 150, and high thickening/low abrasion composite exhibit oil absorption properties
in excess of 150. Such an in situ, simultaneously produced precipitated silica/silica gel
combination provides such unexpectedly effective low abrasion and high cleaning
capability and different thickening characteristics as compared to physical mixtures of
such components. Encompassed within this invention is a unique method for making
such gel/precipitated silica composite materials for such a purpose, as well as the
different materials within the structure ranges described above and dentifrices comprising
such.

Background of the Prior Art
An abrasive substance has been included in conventional dentifrice compositions
in order to remove various deposits, including pellicle film, from the surfaee of teeth.
Pellicle film is tightly adherent and often contains brown or yellow pigments which
impart an unsightly appearance to the teem. While cleaning is important, the abrasive
should not be so aggressive so as to damage the teem. Ideally, an effective dentifrice
abrasive material maximizes pellicle film removal while causing minimal abrasion and
damage to the hard tooth tissues. Consequently, among other things, the performance of
the dentifrice is highly sensitive to the extent of abrasion caused by the abrasive
ingredient. Conventionally, the abrasive cleaning material has been introduced in
flowable dry powder form to dentifrice compositions, or via redispersions of flowable dry
powder forms of the polishing agent prepared before of at the time of formulating the
dentifrice. Also, and more recently, slurry forms of such abrasives have been provided to
facilitate storage, transport, and introduction within target dentifrice formulations.
Synthetic low-structure silicas have been utilized for such a purpose due to the
effectiveness such materials provide as abrasives, as well as low toxicity characteristics
and compatibility with other dentifrice components, such as sodium fluoride, as one
example. When preparing synthetic silicas, the objective is to obtain silicas which
provide maximal cleaning with minimal impact to the hard tooth surfaces. Dental
researchers are continually concerned with identifying abrasive materials that meet such
objectives.

Synthetic silicas (of higher structure) have also been utilized as thickening agents
for dentifrices and other like paste materials in order to supplement and modify the
rheological properties for improved control, such as viscosity build, stand up, brush sag,
and the like. For toothpaste formulations, for example, there is a need to provide a stable
paste that can meet a number of consumer requirements, including, and without
limitation, the ability to be transferred out of a container (such as a tube) via pressure
(i.e., squeezing of the tube) as a dimensionally stable paste and to return to its previous
state upon removal of such pressure, the ability to be transferred in such a manner to a
brushhead easily and without flow out of the tube during and after such transference, the
propensity to remain dimensionally stable on the brush prior to use and when applied to
target teeth prior to brushing, and the exhibiting of proper mouthfeel for aesthetic
purposes, at least, for the benefit of the user.
Generally, dentifrices comprise a majority of a humectant (such as sorbitol,
glycerin, polyethylene glycol, and the like) in order to permit proper contact with target
dental subjects, an abrasive (such as precipitated silica) for proper cleaning and abrading
of the subject teeth, water, and other active components (such as fluoride-based
compounds for anticaries benefits). The ability to impart proper rheological benefits to
such a dentifrice is accorded through the proper selection and utilization of thickening
agents (such as hydrated silicas, hydrocolloids, gums, and the like) to form a proper
network of support to properly contain such important humectant, abrasive, and anticaries
ingredients. It is thus evident that formulating proper dentifrice compositions can be
rather complex, both from a compounding standpoint as well as the number, amount, and
type of components present within such formulations. As a result, although it is not a

high prioirity within the dentifrice industry, the ability to reduce the number of such
components, or attempt to provide certain components mat meet at least two of these
needed properties could potentially reduce formulation complexity, not to mention
potentially reducing the overall manufacturing costs.
A number of water-insoluble, abrasive polishing agents have been used or
described for dentifrice compositions. These abrasive polishing agents include natural
and synthetic abrasive particulate materials. The generally known synthetic abrasive
polishing agents include amorphous precipitated silicas and silica gels and precipitated
calcium carbonate (PCC). Other abrasive polishing agents for dentifrices have included
chalk, magnesium carbonate, dicalcium phosphate and its dihydrate forms, calcium
pyrophosphate, zirconium silicate, potassium metaphosphate, magnesium
orthophosphate, tricalcium phosphate, perlite, and the like.
Synthetieally-produeed precipitated low-structure silicas, in particular, have been
used as abrasive components in dentifrice formulations due to their cleaning ability,
relative safeness, and compatibility with typical dentifrice ingredients, such as
humectants, thickening agents, flavoring agents, anticaries agents, and so forth. As
known, synthetic precipitated silicas generally are produced by the destabilization and
precipitation of amorphous silica from soluble alkaline silicate by the addition of a
mineral acid and/or acid gases under conditions in which primary particles initially
formed tend to associate with each other to form a plurality of aggregates (i.e., discrete
clusters of primary particles), but without agglomeration into a three-dimensional gel
structure. The resulting precipitate is separated from the aqueous fraction of the reaction
mixture by filtering, washing, and drying procedures, and then the dried product is

mechanically communuted in order to provide a suitable particle size and size
distribution.
The silica drying procedures are conventionally accomplished using spray drying,
nozzle drying (e.g., tower or fountain), wheel drying, flash drying, rotary wheel drying,
oven/fluid bed drying, and the like.
As it is, such conventional abrasive materials suffer to a certain extent from
limitations associated with maximizing cleaning and minimizing dentin abrasion. The
ability to optimize such characteristics in the past has been limited generally to
controlling the structures of the individual components utilized for such purposes.
Examples of modifications in precipitated silica structures for such dentifrice purposes
are described in the art within such publications as U.S. Pat. Nos. 3,967,563,3,988,162,
4,420,312, and 4,122,161 to Wason, U.S. Pat. Nos. 4,992,251 and 5,035,879 to Aldcroft
et al., U.S. Pat. No. 5,098,695 to Newton et al., and U.S. Pat. Nos. 5,891,421 and
5,419,888 to McGill et al. Modifications in silica gels have also been described within
such publications as U.S. Pat. Nos. 5,647,903 to McGill et al., U.S. Pat. No. 4,303,641, to
DeWolf, H et al., U.S. Pat. No. 4,153,680, to Seybert, and U.S. Pat. No. 3,538,230, to
Pader et al. Such disclosures teach improvement in such silica materials in order to
impart increased pellicle film cleaning capacity and reductions in dentin abrasion levels
for dentifrice benefits. However, these typical improvements lack the ability to deliver
preferred property levels that accord a dentifrice producer the ability incorporate such an
individual material in different amounts with other like components in order to effectuate
different resultant levels of such cleaning and abrasion characteristics. To compensate
for such limitations, attempts have been undertaken to provide various combinations of

silicas to permit targeting of different levels. Such silica combinations involving
compositions of differing particle sizes and specific surface areas are disclosed in U.S.
Pat. No. 3,577,521. to Karlheinz Scheller et al., U.S. Pat. No. 4,618,488 to Macyarea et
al., U.S. Pat. No. 5,124,143 to Muhlemann, and U.S. Pat. No. 4,632,826 to Ploger et al.
Such resultant dentifrices, however, fail to provide desired levels of abrasion and high
pellicle cleaning simultaneously.
Another attempt has been made to provide physical mixtures of precipitated
silicas of certain structures with silica gels, notably within U.S. Pat. 5,658,553 to Rice. It
is generally accepted that silica gels exhibit edges, and thus theoretically exhibit the
ability to abrade surfaces to a greater degree, than precipitated silicas, even low
structured types. Thus, the blend of such materials together within this patent provided,
at that time, an improvement in terms of controlled but higher levels of abrasiveness
coupled with greater pellicle film cleaning ability than precipitated silicas alone. In such
a disclosure, it is shown that separately produced and co-incorporated silica gels and
precipitated silicas can permit increased PCR and RDA levels but with apparently greater
control for lower abrasive characteristics than for previously provided silicas exhibiting
very high PCR results. Unfortunately, although these results are certainly a step in the
right direction, there is still a largely unfulfilled need to provide a silica-based dental
abrasive that exhibits sufficiently high pellicle film cleaning properties with
simultaneously lower radioactive dentin abrasive characteristics such mat film removal
can be accomplished without deleterious dentin destruction. In effect, the need is for a
safer abrasive mat exhibits a significantly higher PCR level versus RDA level than has
previously been provided within the dental silica industry. Again, the Rice patent is

merely a start toward desirable abrasive characteristics. Furthermore, the requirement to
produce these separate gel and precipitate materials and meter them out for proper target
levels of such characteristics adds costs and process steps to the manufacturing
procedure. A manner of providing the benefits of such combinations, but to a very high
level of pellicle film cleaning and at a relatively low to moderate degree of dentin
abrasion, with simultaneous facilitation of incorporation within dentifrice formulation are
thus unavailable to the industry at this time.
There is always a desire to limit the number of additives required for purchase,
storage and introduction within dentifrice formulations. As such, the ability to provide
simultaneous thickening and abrasive characteristics to avoid the addition of multiple
components for such properties is an unmet need within the industry.
Objects and Summary of the Invention
It has now been found that modifications in the processes for producing
precipitated silicas can result in the in situ simultaneous production of targeted amounts
of silica gels therein, particularly those in which the final structure of the in situ generated
composite can be controlled. Such a novel method thus permits the production of in situ
generated gel/precipitate silica materials that provide excellent dentin abrasion and
pellicle film cleaning capabilities within dentifrices or, in the alternative, such
formulations that exhibit excellent thickening properties as well as desirable abrasive and
cleaning properties through the introduction of such a singularly produced, stored, and
introduced additive.

In pairticular, the specific in situ formed composites exhibit very high levels
pellicle film cleaning properties compared with lower radioactive dentin abrasion results
such that the resultant materials can be added with other abrasive materials (such as lower
structure precipitated silicas, calcium carbonates, and the like) for the dentifrice producer
to target certain high levels of cleaning with lower abrasiveness thus providing the
optimization of cleaning while providing a larger margin of abrasion protection to the
ultimate user. It is also believed, without intending to be bound to any specific scientific
theory, that the increased amount of silica gel within the final composite materials aids in
providing narrower particle size ranges in order to contribute a controlled result of high
cleaning and reduced dentin abrasion levels. As will be discussed in greater detail below,
the physically mixed combination of such materials (i.e., not simultaneously produced
within the same reaction) has been found to impart limited levels of such properties,
namely the need to provide materials (particularly a precipitated silica component) that
exhibits an extremely high, potentially deleterious dentin abrasion level in order to
impart, at the same time, an acceptable high pellicle film cleaning level. The novel in
situ generated precipitated/gel combination silicas unexpectedly provide a higher degree
of pellicle film cleaning with a significantly lower dentin abrasion value, thus according
the dentifrice industry not only a potentially more desirable lower abrasive material for
better dental protection. It has been realized that the presence of varied amounts of such
a silica gel component permits the benefit of the sharp edges exhibited by the gel
agglomerates for abrasiveness, with the coexistence of variable levels of silica
precipitates of different structures to accord an overall composite exhibiting one of three
general properties: high cleaning, mid-range cleaning, or thickening/low cleaning. Such

general properties are all dependent upon the structure of the overall gel/precipitate
composite, as measured by linseed oil absorption (as noted previously). When produced
in situ, such a resultant gel/precipitate material provides unexpectedly improved
properties as compared with dry blends of such separately produced components. In such
a manner, as one example for the high cleaning variation, it has been found that although
the pellicle film cleaning level is quite high, in fact the resultant dentin abrasion level is
limited, thereby imparting an excellent cleaning material without also imparting too high
an abrasion level to the target dental substrate.
Alternatively, but by no means any less important, is the ability to produce
materials of silica-based components simultaneously within the same reaction medium
that imparts dentin abrasion and pellicle film cleaning characteristics (albeit to a lesser
degree than for those noted in the previous paragraph) and coexistent thickening
properties in order to accord such beneficial results with a single additive. The ability to
control the level of a silica gel in a final composite and/or the target high-, medium-, or
low-structure of the precipitate component therein through modifications in starting
material concentration and/or gel and/or precipitate reaction conditions provides the
ability to control the overall cleaning, abrasive, and/or thickening characteristics of the
composite itself Thus, a composite exhibiting greater thickening and reduced but
effective pellicle film cleaning characteristic will include either higher amounts of silica
gel and/or higher amounts of high-structure precipitate such that the overall composite
exhibits sufficiently high linseed oil absorption (greater than 150 ml/100 g material) to
provide the target desired thickening/low abrasion properties. Thus, by controlling such
silica gel/precipitate production parameters, it has been found that a single additive can

provide these diverse cleaning abrasion, and/or thickening properties without resorting to
multiple additions of potentially expensive and/or difficult to incorporate materials for
the same purpose.
All parts, percentages and ratios used herein are expressed by weight unless
otherwise specified. All documents cited herein are incorporated by reference.
Accordingly, it is one object of the present invention to provide a precipitated
silica and gel silica composite material providing improved pellicle film cleaning without
an unacceptably high corresponding increase in dentin or enamel abrasion. Another
object of the present invention is to provide a new method for the production of such
effective precipitated/gel silica combinations wherein such materials are produced
simultaneously and in situ, thereby permitting the proper ratios of such materials to be
made during production of the materials, rather than during dentifrice production. Also
an object of this invention is to provide an in situ generated precipitated/gel silica
composite material wherein the linseed oil absorption levels exhibited thereby are within
one of three ranges: 40 to 100 ml oil absorbed/100 g composite material for a very high
cleaning material, greater than 100 and up to 150 ml/100g for a mid-range high cleaning
material, and in excess of 150 for a cleaning/thickening/low abrasion material.
Accordingly, this invention encompasses a method for producing simultaneously
silica gels and precipitated silicas, said method comprising the sequential steps of
a) admixing a sufficient amount of an alkali silicate and an acidulating agent
together to form a silica gel composition; and without first washing, purifying, or
modifying said formed silica gel composition,

b)stimultaneously introducing to said silica gel composition a sufficient amount
of an alkali silicate and an acidulating agent to form a precipitated silica, thereby
producing a precipitate/gel silica combination. Encompassed as well within this
invention is the product of such a process wherein the silica gel amount present therein is
from 5 to 80% by volume of the total precipitated/gel silica resultant simultaneously
produced combination. Further encompassed within this invention are the composite
materials listed above in the three ranges of oil absorption measurements, and dentifrice
formulations comprising such materials as well as the product of the inventive process
noted above.
Generally, synthetic precipitated silicas are prepared by admixing dilute alkali
silicate solutions with strong aqueous mineral acids under conditions where aggregation
to the sol and gel cannot occur, stirring and then filtering out the precipitated silica. The
resulting precipitate is next washed, dried and comminuted to desired size.
Generally, as well, silica gels include silica hydrogels, hydrous gels, aerogels, and
xerogels. Silica gels are also formed by reacting alkali silicate solutions with strong acids
or vice-versa, to form a hydrosol and aging the newly formed hydrosol to form the
hydrogel. The hydrogel is then washed, dried and comminuted to form the desired
materials.
As noted above, the separate production of such materials has historically
required manufacture of these separate materials, and proper metering of the two together
during the incorporation within a dentifrice formulation in such a way as to provide the
desired cleaning/abrasion levels thereof.

To the contrary,the inventive method for simultaneous production of such
materials permits the producer to target a range of amounts of silica gel and precipitated
silica components as well as structures of precipitated components to impart the desired
level of cleaning/abrasion through controlled parameters during production, a significant
difference from previous physicals mixtures (i.e., dry blends) of such materials through
separate incorporation. Basically, the novel method entails targeting the amount of silica
gel desired and specifically selecting certain reaction conditions in order to generate such
a desired level during amorphous precipitated silica production.
The inventive abrasive compositions are ready-to-use additives in the preparation
of oral cleaning compositions, such as dentifrices, toothpastes, and the like, particularly
suited as a raw material in a toothpaste making process. Furthermore, such silica
products can be utilized in applications wherein sharp edges and lower abrasiveness may
be desired, such as, without limitation, foam inhibitors within certain formulations, such
as, without limitation, automatic dishwashing detergents. Additional potential uses of
such materials include food carriers, rubber additives and carriers, cosmetic additives,
personal care additives, plastic antiblocking additives, and pharmaceutical additives,
without limitation.
Brief Description of the [Accompanying Drawings
FIG. 1 is a graphical representation of the correlation between dentin abrasion and
pellicle film cleaning ratios for a dentifrice composition for inventive in situ produced
composites of gel/precipitated silica and comparative physical mixtures of such materials.

FIG.2 is a graphical representation of the correlation between thickening ability
and silica gel structure for inventive in situ produced composites of gel/precipitated silica
and comparative physical mixtures of such materials.
FIG. 3 is a graphical representation of the correlation between the values of dentin
abrasion and pellicle film cleaning measurements for a dentifrice composition for
inventive in situ produced composites of gel/precipitated silica and the values of the same
measurements for comparative conventional dental abrasives.
Detailed Description of the Invention
The abrasive and/or thickening combinations used in the present invention are in-
situ formed materials that can be readily formulated on demand with other ingrethents to
prepare oral cleaning compositions having a high cleaning efficacy without causing
undue abrasion on tooth surfaces. The essential as well as optional components of the
abrasive and/or thickening compositions and related methods of making same of the
present invention are described in more detail below.
General Production Method
The silica compositions of the present invention are prepared according to the
following two-stage process with a silica gel being formed in the first stage and
precipitated silica formed in the second stage. In this process, an aqueous solution of an
alkali silicate, such as sodium silicate, is charged into a reactor equipped with mixing
means adequate to ensure a homogeneous mixture, and the aqueous solution of an alkali
silicate in the reactor preheated to a temperature of between about 40°C and about 90°C.

Preferably,the aqueous alkali silicate solution has an alkali silicate concentration of
approximately 3.0 to 35 wt%, preferably from about 3.0 to about 25 wt%, and more
preferably from about 3.0 to about 15 wt%. Preferably the alkali silicate is a sodium
silicate with a SiO2:Na2O ratio of from about 1 to about 4.5, more particularly from about
1.5 to about 3.4. The quantity of alkali silicate charged into the reactor is about 10 wt%
to 80 wt% of the total silicate used in the batch. Optionally, an electrolyte, such as
sodium sulfate solution, may be added to the reaction medium (silicate solution or water).
Next, an aqueous acidulating agent or acid, such as sulfuric acid, hydrochloric acid, nitric
acid, phosphoric acid, and so forth (preferably sulfuric acid), added as a dilute solution
thereof (e.g., at a concentration of between about 4 to 35 wt %, more typically about 9.0
to 15.0 wt %) is added to the silicate to form a gel. Once the silica gel is produced and the
pH adjusted to the desired level, such as between about 3 and 10, the acid addition is
stopped and the gel is heated to the batch reaction temperature, preferably between about
65°C to about 100°C. It is important to note that after this first stage is completed, the
produced silica gel is not modified in any way. Thus, this resultant gel is not washed,
purified, cleaned, etc., prior to commencement of the second stage.
Next, the second stage begins after the gel reaction temperature is increased, with
the simultaneous addition to the reactor of: (1) an aqueous solution of the same
acidulating agent previously used and (2) additional amounts of an aqueous solution
containing the same species of alkali silicate as is in the reactor, the aqueous solution
being preheated to a temperature of about 65°C to about 100°C. The rate of acidulating
agent and silicate additions can be adjusted to control the simultaneous addition pH
during the second stage reaction. This pH control can be used to control product physical

properties, generally with higher average batch pH providing lower structure silica
products and relatively lower average batch pH providing higher structure silica products.
High shear recirculation may be utilized, and the acid solution addition continues until
the reactor batch pH drops to between about 4 to about 9. For purposes of this inventive
method, the term "average batch pH" is intended to mean the average pH obtained by
measuring the pH level every 5 minutes during the precipitate formation stage and
averaging the total aggregate over total time elapsed.
After the inflows of the acidulating agent and the alkali silicate are stopped, the
reactor batch allowed to age or "digest" for between 5 minutes to 30 minutes, with the
reactor contents being maintained at a constant pH. After the completion of digestion,
the reaction batch is filtered and washed with water to remove excess by-product
inorganic salts until the wash water from the silica filter cake results in at most 5% salt
byproduct content as measured by conductivity.
The silica filter cake is slurried in water, and then dried by any conventional
drying techniques, such as spray drying, to produce an amorphous silica containing from
about 3 wt% to about 50 wt% of moisture. The silica may then be milled to obtain the
desired median particle size of between about 3 µm to 25 µm, preferably between about 3
µm to about 20 µm. Classification of even narrower median particle size ranges may aid
in providing increased cleaning benefits as well.
In addition to the above-described production process methodologies of
precipitating the synthetic amorphous silicas, the preparation of the silica products is not
necessarily limited thereto and it also can be generally accomplished in accordance with
the methodologies described, for example, in prior U.S. Pat. Nos. 3,893,840,3,988,162,

4,067,746, 4,340,583,and 5,891,421, all of which are incorporated herein by reference,
as long as such methods are appropriately modified to incorporate recirculation and high
shear treatments. As will be appreciated by one skilled in the art, reaction parameters
which affect the characteristics of the resultant precipitated silica include: the rate and
timing at which the various reactants are added; the levels of concentration of the various
reactants; the reaction pH; the reaction temperature; the agitation of the reactants during
production; and/or the rate at which any electrolytes are added.
Alternative methods of production for this inventive material include in slurry
form such as, without limitation, procedures taught within U.S. Pat. No. 6,419,174, to
McGill et al., as well as filter press slurry processes as described within and throughout
U.S. Published Pat. Appl. No. 20030019162 to Huang.
The inventive silica composite materials may be characterized and separated, as
discussed above, into three distinct categories, dependent upon the linseed oil absorption
ranges exhibited within each. The oil absorption test, discussed in greater detail below, is
generally used to determine structures of precipitated silica materials as set forth in J.
Soc. Cosmet. Chem., 29,497-521 (August 1978), and Pigment Handbook: Volume 1,
Properties and Economics, 2nd ed., John Wiley & Sons, 1988, p. 139-159. For this
invention, however, it is important to note that such a test has now been utilized to
determine the structure of the overall gel/precipitate silica composite instead. Thus, the
three basic types of inventive materials are categorized as defined above, and as
discussed in the following sections.

The inventive in situ generated composites (also referred to as "combinations") of
_el and precipitate are useful for various functions, including, without limitation,
three primary types: i) high-cleaning, dental abrasives with correlative lower
abrasiveness (with an RDA level of less than 250, for instance) than typical high-cleaning
silica-based products; ii) mid-range cleaning dental abrasives with reduced high cleaning
levels (as compared with the high cleaning materials from above), but much lower RDA
measurements (at most about 150, for instance); and iii) thickening (viscosity-modifying)
products that exhibit certain levels of cleaning and abrasiveness (such as an exhibited
PCR of less than 90 and a measured RDA of below 80). Production of each type is based
upon different factors, such as reaction conditions (e.g., temperature, agitation/shear,
addition rates of reactants, amount of gel component, and the like), and concentrations of
reactants (e.g., mole ratios of silicate to acid, as one example). These will be further
delineated separately below.
High-Cleaning Abrasive Materials
The in situ process of this invention has surprisingly yielded, with selectivity
followed in terms of reaction pH, reactant composition, amount of gel component, and, as
a result, structure of the resultant gel/precipitate silica composite materials made
therefrom, abrasive materials that exhibit exceedingly high pellicle film cleaning
properties. Such high-cleaning materials may be adjusted to target lower radioactive
dentin abrasion levels without compromising the cleaning benefits, again, through the
production of certain low structure gel/precipitate silica composite materials. Such
materials are exemplified below in Examples 4,6,7,11, and 15, at least and show the

ability to clean without detrimental exaggerated dentin abrasion (within dentifrice
formulas 1,3, and 4, for example). Such products may be utilized as the sole
cleaning/abrasive component within a dentifrice or, in one potentially preferred
embodiment, may be used as a supplement with other lower abrasive additives, for
targeting an overall cleaning and abrasive level for a dentifrice formulation.
For this high cleaning material, the gel component is present in an amount
between 5 and 50% by volume of the ultimately formed gel/precipitate silica composite
material (and thus the precipitated silica component is present in an amount of from 95 to
50% by volume as a result). Although the amount of gel possible to form a high cleaning
material may be as high as 50% of the composite material, preferably such an amount is
much lower mainly because it was found that the higher the amount of gel present within
a high cleaning material, the greater amount of low structure precipitated silica
component required to be produced during the following phase. Thus, the overall amount
of gel to be produced is preferably relatively low (from 10 to 25%, for instance). Such
percentages of gel component actually represent the amount of silicate present during the
production phases for each different silica material. Thus, a 10% gel measurement
reflects the presence of 10% of the total silicate reactant volume within the reactor during
which the gel is initially made (as one example). Subsequent to initial gel production,
the remaining 90% silicate reactant volume is used for precipitated silica component
production. It is important to note, however, that upon the initiation of the precipitate
formation phase, some of the silicate may actually produce gel, but the determination of
percentages of each component within the ultimately formed composite material does not
reflect such a possibility. Thus, the percentages noted above are merely best estimates,

rather than concrete determinations of final amounts of components. Such an issue exists
within the remaining in situ gel/precipitate composite material categories as well.
Generally, it has been determined that such specific high-cleaning abrasives may
be produced through a method of admixing a suitable acid and a suitable silicate starting
material (wherein the acid concentration, in aqueous solution, is from 5 to 25 %,
preferably from 10 to 20%, and more preferably from 10 to 12%, and the concentration
of the silicate starting material is from 4 to 35%, also within an aqueous solution), to
initially form a silica gel. Subsequent to gel formation, sufficient silicate and acid are
added (without any appreciable degree of washing, or other type of purification, or
physical modification of the gel) to the formed gel for further production of varying
structure (preferably low in structure, but other structures silica products may result
during manufacturing as long as the overall structure is sufficient to accord the necessary
levels of pellicle film cleaning) precipitated silica component desired for a high cleaning
composite material to be formed. The pH of the overall reaction may be controlled
anywhere within the range of 3 to 10, with a higher pH desired for low-structure
precipitated silica production. It has been realized that in order to provide a high
cleaning, moderate to low abrasive material through this process, the amount of gel is
preferably lower (as noted above, from 10 to 30% by volume of the composite) and the
amount of low structure precipitated silica is preferably relatively high (from 90 to 70%
by volume of the composite). In order to exhibit the proper PCR and RDA levels
associated with this category, the resultant gel/silica composite material must exhibit a
linseed oil absorption of between 40 and 100 ml oil/100 g material.

Broadly, the inventive high cleaning gel/precipitated silica combination generally
have the following properties: 10% Brass Einlehner hardness values in the range between
about 5 and 30 mg loss/100,000 revolutions, and, within a test dentifrice formulation (as
presented below within the examples) RDA (Radioactive Dentin Abrasion) values
between about 180 to about 240, and (within the same test dentifrice formulation) PCR
(Pellicle Cleaning Ratio) values of 90 to 160, with a ratio of PCR to RDA within the
range of 0.45 to 0.7.
Mid-Range Cleaning Abrasives
The in situ process of this invention has also surprisingly yielded, with similar
degrees of selectivity followed in terms of reaction pH, reactant concentrations, amount
of gel component, and, as a result, overall structure of the resultant gel/precipitate silica
composite materials made therefrom as for the high cleaning materials described above, a
method for producing a mid-range product (essentially reduced, but still relatively high,
cleaning levels with lower abrasion levels) composites as well. Thus, selection of
differing concentrations, pH levels, ultimate gel proportions, among other things, can
produce gel/precipitate silica composite materials of overall medium structures in order
to accord relatively high pellicle film cleaning results, with lower abrasive properties as
compared with the high cleaning materials described above. Examples 5,10,12,14,16,
and 17, at least, below show certain methods of producing such mid-range abrasive
products (and further exemplified within dentifrice formulations 2,7, 9, and 10, below).

For this mid-range cleaning material, the gel component is present in an amount
between 10 and 60% by weight of the ultimately formed gel/precipitate silica composite
material (and thus the precipitated silica component is present in an amount of from 90 to
40% by weight as a result). Although the amount of gel possible to form a high cleaning
material may be as high as 60% of the composite material, preferably such an amount is
much lower mainly because it was found that the higher the amount of gel present within
a mid-range cleaning material, the greater amount of low structure precipitated silica
component required to be produced during the following phase. Thus, the overall amount
of gel to be produced is preferably relatively low (from 20 to 33%, for instance). Such
percentages of gel component actually represent the amount of silicate present during the
production phases for each different silica material, as described above for the high
cleaning material.
Generally, it has been determined that such specific mid-range cleaning abrasives
may be produced through a method of admixing a suitable acid and a suitable silicate
starting material (wherein the acid concentration, in aqueous solution, is from 5 to 25 %,
preferably from 10 to 20%, and more preferably from 10 to 12%, and the concentration
of the silicate starting material is from 4 to 35%, also within an aqueous solution), to
initially form a silica gel. Subsequent to gel formation, sufficient silicate and acid are
added (without any appreciable degree of washing, or other type of purification, or
physical modification of the gel) to the formed gel for further production of appropriately
structured precipitated silica component desired for a mid-range cleaning composite
material to be formed. The pH of the overall reaction may be controlled anywhere within
the range of 3 to 10. Depending on the amount of gel initially formed, the amount and

structure of presipited silica component may be targeted in much the same way as for
the high cleaning material. It has been realized that in order to provide a mid-range
cleaning, low abrasive material through this process, as compared with the high cleaning
materials noted above, the amount of gel is preferably higher (as noted above, from 10 to
60% by volume of the composite, preferably from 20 to 33%) and the amount of low
structure precipitated silica is preferably lower (from 90 to 40% by volume of the
composite, preferably from 80 to 67%). In order to exhibit the proper PCR and RDA
levels associated with this category, the resultant gel/silica composite material must
exhibit a linseed oil absorption of greater than 100 up to 150 ml oil/100 g material.
Broadly, the inventive mid-range cleaning gel/precipitated silica combination
generally have the following properties: 10% Brass Einlehner hardness values in the
range between 2.5 and 12.0, and, within a test dentifrice formulation (as presented below
within the examples) RDA (Radioactive Dentin Abrasion) values between about 95 to
about 150, and (within the same test dentifrice formulation) PCR (Pellicle Cleaning
Ratio) values of 90 to 120, with a ratio of PCR to RDA within the range of 0.7 to 1.1.
Thickening Cleaners/Abrasives
Lastly, again, in much the manner as the two above types of abrasives, it has
surprisingly been found that silica-based viscosity-modifying materials may be provided
that also exhibit a certain degree of abrasiveness and cleaning through the utilization of
the inventive in situ process. The presence of a simultaneously produced gel/precipitate
appears to surprisingly accord a certain abrasive property within a material that, when
produced via a high structure silica production method, provides an effective thickening

(or other type of viscosity modification) within dentifrice formulations. In such a
manner, such a thickening agent may be added not only for its viscosity-modifying effect,
but also to supplement simultaneously present higher cleaning and/or abrasive dentifrice
components. Examples 3, 8,9, and 13, at least, provide a showing of general methods of
producing such thickening abrasives (and further exemplified within dentifrice
formulations 5,6, and 8, below).
For this low cleaning level material, the gel component is present in an amount
between 20 and 85% by volume of the ultimately formed gel/precipitate silica composite
material (and thus the precipitated silica component is present in an amount of from 80 to
15% by volume as a result, with such a component preferably present in a high structure
form). Although the amount of gel possible to form a high cleaning material may be as
low as 20% of the composite material, preferably such an amount is much higher mainly
because it was found that the lower the amount of gel present within a thickening
abrasive material, the greater amount of high structure precipitated silica component
required to be produced during the following phase. Thus, the overall amount of gel to
be produced is preferably relatively high (from 45 to 65%, 50% more preferably, for
instance). Such percentages of gel component actually represent the amount of silicate
present during the production phases for each different silica material, as described above
for the other categories of cleaning materials.
Generally, it has been determined that such specific thickening abrasives may be
produced through a method of admixing a suitable acid and a suitable silicate starting
material (wherein the acid concentration, in aqueous solution, is from 5 to 25 %,
preferably from 10 to 20%, and more preferably from 10 to 12%, and the concentration

of the silicate starting material is from 4 to 35%, also within an aqueous solution), to
initially form a silica gel. Subsequent to gel formation, sufficient silicate and acid are
added (without any appreciable degree of washing, or other type of purification, or
physical modification of the gel) to the formed gel for further production of high structure
precipitated silica component desired for a thickening abrasive composite material to be
formed. The pH of the overall reaction may be controlled anywhere within the range of 3
to 10. Depending on the amount of gel initially formed, the amount and structure of
precipitated silica component may be targeted by reacting the subsequent silicate and acid
reactants within a more acidic medium to form greater amounts of high structure
precipitated silica components. It has been realized that in order to provide a thickening
abrasive material through this process, the amount of gel is preferably higher (as noted
above, from 20 to 85% by volume of the composite, preferably from 45 to 65%) and the
amount of low structure precipitated silica is preferably relatively low (as low as
possible), while the amount of high structure precipitated silica is preferably relatively
high (from 80 to 15% by volume of the composite, preferably from 55 to 35%). In order
to exhibit the proper PCR and RDA levels associated with this category, the resultant
gel/silica composite material must exhibit a linseed oil absorption of greater than 150,
possibly with a maximum of about 225 ml oil/100 g material.
Broadly, the inventive thickening abrasive gel/precipitated silica combination
generally have the following properties: 10% Brass Einlehner hardness values in the
range between 1.0 and 5.0 mg loss/100,000 revolutions, and, within a test dentifrice
formulation (as presented below within the examples) RDA (Radioactive Dentin
Abrasion) values between about 20 to about 80, and (within the same test dentifrice

formulation) PCR (Pellicle Cleaning Ratio) values of about 50 to 80, with a ratio of PCR
to RDA within the range of 0.8 to 3.5.
Dentifrice Uses of the Inventive Materials
The inventive in situ generated gel/precipitate silica composite materials
described herein may be utilized alone as the cleaning agent component provided in the
dentifrice compositions of this invention, although, at least for the high cleaning category
materials, the moderately high RDA levels may be unacceptable to some consumers.
Thus, a combination of the inventive composite materials with other abrasives physically
blended therewith within a suitable dentifrice formulation is potentially preferred in this
regard in order to accord targeted dental cleaning and abrasion results at a desired
protective level. Thus, any number of other conventional types of abrasive additives may
be present within inventive dentifrices in accordance with this invention. Other such
abrasive particles include, for example, and without limitation, precipitated calcium
carbonate (PCC), ground calcium carbonate (GCC), dicalcium phosphate or its dihydrate
forms, silica gel (by itself, and of any structure), amorphous precipitated silica (by itself,
and of any structure as well), perlite, titanium dioxide, calcium pyrophosphate, hydrated
alumina, calcined alumina, insoluble sodium metaphosphate, insoluble potassium
metaphosphate, insoluble magnesium carbonate, zirconium silicate, aluminum silicate,
and so forth, can be introduced within the desired abrasive compositions to tailor the
polishing characteristics of the target formulation (dentifrices, for example, etc.), if
desired, as well.

The precipitate/gel silica combination described above, when incorporated into
dentifrice compositions, is present at a level of from about 5% to about 50% by weight,
more preferably from about 10% to about 35% by weight, particularly when the
dentifrice is a toothpaste. Overall dentifrice or oral cleaning formulations incorporating
the abrasive compositions of this invention conveniently can comprise the following
possible ingrethents and relative amounts thereof (all amounts in wt %):

In addition, as noted above, the inventive abrasive could be used in conjunction
with other abrasive materials, such as precipitated silica, silica gel, dicalcium phosphate,
dicalicum phosphate dihydrate, calcium metasilicate, calcium pyrophosphate, alumina,
calcined alumina, aluminum silicate, precipitated and ground calcium carbonate, chalk,
bentonite, particulate thermosetting resins and other suitable abrasive materials known to
a person of ordinary skill in the art

In addition to the abrasive component, the dentifrice may also contain one or
more organoleptic enhancing agents. Organoleptic enhancing agents include humectants,
sweeteners, surfactants, flavorants, colorants and thickening agents, (also sometimes
known as binders, gums, or stabilizing agents),
Humectants serve to add body or "mouth texture" to a dentifrice as well as
preventing the dentifrice from drying out. Suitable humectants include polyethylene
glycol (at a variety of different molecular weights), propylene glycol, glycerin (glycerol),
erythritol, xylitol, sorbitol, mannitol, lactitol, and hydrogenated starch hydrolyzates, as
well as mixtures of these compounds. Typical levels of humectants are from about 20
wt% to about 30 wt% of a toothpaste composition.
Sweeteners may be added to the toothpaste composition to impart a pleasing taste
to the product. Suitable sweeteners include saccharin (as sodium, potassium or calcium
saccharin), cyclamate (as a sodium, potassium or calcium salt), acesulfane-K, thaumatin,
neohisperidin dihydrochalcone, ammoniated glycyrrhizin, dextrose, levulose, sucrose,
mannose, and glucose.
Surfactants are used in the compositions of the present invention to make the
compositions more cosmetically acceptable. The surfactant is preferably a detersive
material which imparts to the composition detersive and foaming properties. Suitable
surfactants are safe and effective amounts of anionic, cationic, nonionic, zwitterionic,
amphoteric and betaine surfactants such as sodium lauryl sulfate, sodium dodecyl
benzene sulfonate, alkali metal or ammonium salts of lauroyl sarcosinate, myristoyl
sarcosinate, palmitoyl sarcosinate, stearoyl sarcosinate and oleoyl sarcosinate,,
polyoxyethylene sorbitan monostearate, isostearate and laurate, sodium lauryl

sulfoacetate, N-lauroyl sarcosine, the sodium, potassium, and ethanolamine salts of N-
lauroyl, N-myristoyl, or N-palmitoyl sarcosine, polyethylene oxide condensates of alkyl
phenols, cocoamidopropyl betaine, lauramidopropyl betaine, palmityl betaine and the
like. Sodium lauryl sulfate is a preferred surfactant. The surfactant is typically present in
the oral care compositions of the present invention in an amount of about 0.1 to about
15% by weight, preferably about 0.3% to about 5% by weight, such as from about 0.3 %
to about 2%, by weight.
Flavoring agents optionally can be added to dentifrice compositions. Suitable
flavoring agents include, but are not limited to, oil of wintergreen, oil of peppermint, oil
of spearmint, oil of sassafras, and oil of clove, cinnamon, anethole, menthol, thymol,
eugenol, eucalyptol, lemon, orange and other such flavor compounds to add fruit notes,
spice notes, etc. These flavoring agents consist chemically of mixtures of aldehydes,
ketones, esters, phenols, acids, and aliphatic, aromatic and other alcohols.
Colorants may be added to improve the aesthetic appearance of the product.
Suitable colorants are selected from colorants approved by appropriate regulatory bothes
such as the FDA and those listed in the European Food and Pharmaceutical Directives
and include pigments, such as TiO2, and colors such as FD&C and D&C dyes.
Thickening agents are useful in the dentifrice compositions of the present
invention to provide a gelatinous structure that stabilizes the toothpaste against phase
separation. Suitable thickening agents include silica thickener; starch; glycerite of starch;
gums such as gum karaya (sterculia gum), gum tragacanth, gum arabic, gum ghatti, gum
acacia, xanthan gum, guar gum and cellulose gum; magnesium aluminum silicate
(Veegum); carrageenan; sodium alginate; agar-agar; pectin; gelatin; cellulose compounds

such as cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl
cellulose, hydroxymethyl cellulose, hydroxymethyl carboxypropyl cellulose, methyl
cellulose, ethyl cellulose, and sulfated cellulose; natural and synthetic clays such as
hectorite clays; as well as mixtures of these compounds. Typical levels of thickening
agents or binders are from about 0 wt% to about 15 wt% of a toothpaste composition.
Therapeutic agents are optionally used in the compositions of the present
invention to provide for the prevention and treatment of dental caries, periodontal disease
and temperature sensitivity. Examples of therapeutic agents, without intending to be
limiting, are fluoride sources, such as sodium fluoride, sodium monofluorophosphate,
potassium monofluorophosphate, stannous fluoride, potassium fluoride, sodium
fluorosilicate, ammonium fluorosilicate and the like; condensed phosphates such as
tetrasodium pyrophosphate, tetrapotassium pyrophosphate, disodium dihydrogen
pyrophosphate, trisodium monohydrogen pyrophosphate; tripolyphosphates,
hexametaphosphates, trimetaphosphates and pyrophosphates, such as ; antimicrobial
agents such as triclosan, bisguanides, such as alexidine, chlorhexidine and chlorhexidine
gluconate; enzymes such as papain, bromelain, glucoamylase, amylase, dextranase,
mutanase, lipases, pectinase, tannase, and proteases; quarternary ammonium compounds,
such as benzalkonium chloride (BZK), benzethonium chloride (BZT), cetylpyridinium
chloride (CPC), and domiphen bromide; metal salts, such as zinc citrate, zinc chloride,
and stannous fluoride; sanguinaria extract and sanguinarine; volatile oils, such as
eucalyptol, menthol, thymol, and methyl salicylate; amine fluorides; peroxides and the
like. Therapeutic agents may be used in dentifrice formulations singly or in combination
at a therapeutically safe and effective level.

Preservatives may also be optionally added to the compositions of the present
invention to prevent bacterial growth. Suitable preservatives approved for use in oral
compositions such as methylparaben, propylparaben and sodium benzoate may be added
in safe and effective amounts.
The dentifrices disclosed herein may also a variety of additional ingrethents such
as desensitizing agents, healing agents, other caries preventative agents,
chelating/sequestering agents, vitamins, amino acids, proteins, other anti-plaque/anti-
calculus agents, opacifiers, antibiotics, anti-enzymes, enzymes, pH control agents,
oxidizing agents, antioxidants, and the like
Water provides the balance of the composition in addition to the additives
mentioned. The water is preferably deionized and free of impurities. The dentifrice will
usually comprise from about 20 wt% to about 35 wt% of water.
Useful silica thickeners for utilization within such a toothpaste formulation
include, as a non-limiting example, an amorphous precipitated silica such as
ZEODENT® 165 silica. Other preferred (though non-limiting) silica thickeners are
ZEODENT® 163 and/or 167 and ZEOFREE®153,177, and/or 265 silicas, all available
from J. M. Huber Corporation, Havre de Grace Md., U.S.A.
For purposes of this invention, a "dentifrice" has the meaning defined in Oral
Hygiene Products and Practice, Morton Pader, Consumer Science and Technology Series,
Vol. 6, Marcel Dekker, NY 1988, p. 200, which is incorporated herein by reference.
Namely, a "dentifrice" is "... a substance used with a toothbrush to clean the accessible
surfaces of the teeth. Dentifrices are primarily composed of water, detergent, humectant,
binder, flavoring agents, and a finely powdered abrasive as the principal ingrethent... a

dentifrice is considered to be an abrasive-containing dosage form for delivering anti-
caries agents to the teeth." Dentifrice formulations contain ingrethents which must be
dissolved prior to incorporation into the dentifrice formulation (e.g. anti-caries agents
such as sodium fluoride, sodium phosphates, flavoring agents such as saccharin).
The various silica and toothpaste (dentifrice) properties described herein were
measured as follows, unless indicated otherwise.
The Brass Einlehner (BE) Abrasion test used to measure the hardness of the
precipitated silicas/silica gels reported in this application is described in detail in U.S.
Pat. No. 6,616,916, incorporated herein by reference, involves an Einlehner AT-1000
Abrader generally used as follows: (1) a Fourdrinier brass wire screen is weighed and
exposed to the action of a 10% aqueous silica suspension for a fixed length of time; (2)
the amount of abrasion is then determined as milligrams brass lost from the Fourdrinier
wire screen per 100,000 revolutions. The result, measured in units of mg loss, can be
characterized as the 10% brass Einlehner (BE) abrasion value.
The oil absorption values are measured using the rubout method. This method is
based on a principle of mixing linseed oil with a silica by rubbing with a spatula on a
smooth surface until a stiff putty-like paste is formed. By measuring the quantity of oil
required to have a paste mixture which will curl when spread out, one can calculate the
oil absorption value of the silica—the value which represents the volume of oil required
per unit weight of silica to saturate the silica sorptive capacity. A higher oil absorption
level indicates a higher structure of precipitated silica; similarly, a low value is indicative
of what is considered a low-structure precipitated silica. Calculation of the oil absorption
value was done as follows:


As a first step in measuring refractive index ("RI") and degree of light
transmission, a range of glycerin/water stock solutions (about 10) was prepared so that
the refractive index of these solutions lies between 1.428 and 1.46. The exact
glycerin/water ratios needed depend on the exact glycerin used and is determined by the
technician making the measurement. Typically, these stock solutions will cover the range
of 70 wt% to 90 wt% glycerin in water. To determine Refractive index, one or two drops
of each standard solution is separately placed on the fixed plate of a refractometer (Abbe
60 Refractometer Model 10450). The covering plate is fixed and locked into place. The
light source and refractometer are switched on and the refractive index of each standard
solution is read.
Into separate 20-mI bottles, accurately weighed was 2.0 +/- 0.01 ml of the
inventive gel/precipitate silica product and added was 18.0 +/- 0.01 ml of each respective
stock glycerin/water solution (for products with measured oil absorption above 150, the
test used 1 g of inventive gel/precipitate silica product and 19 g of the stock
glycerin/water solution). The bottles were then shaken vigorously to form silica
dispersion, the stoppers were removed from the bottles, and the bottles were placed in a
desiccator, which was then evacuated with a vacuum pump (about 24 inches Hg).

The dispersions were then de-aerated for 120 minutes and visually inspected for
complete de-aeration. The %Transmittance ("%T") at 590 nm (Spectronic 20 D+) was
measured after the samples returned to room temperature (about 10 minutes), according
to the manufacturer's operating instructions.
The %Transmittance was measured on the inventive product/glycerin/water
dispersions by placing an aliquot of each dispersion in a quartz cuvette and reading the
%T at 590 nm wavelength for each sample on a 0-100 scale. The %Transmittance vs. RI
of the stock solutions used was plotted on a curve. The Refractive index of the inventive
product was defined as the position of the plotted peak maximum (the ordinate or X-
value) on the %Transmittance vs. the RI curve. The Y-value (or abscissa) of the peak
maximum was the %Transmittance.
The surface area of the precipitated silica/silica gel reported herein is determined
by the BET nitrogen adsorption method of Brunaur et al., J. Am. Chem. Soc, 60,309
(1938).
The total pore volume (Hg) is measured by mercury porosimetry using a
Micromeritics Autopore II 9220 apparatus. The pore diameters can be calculated by the
Washburn equation employing a contact angle Theta (0) equal to 140° and a surface
tension gamma equal to 485 dynes/cm. This instrument measures the void volume and
pore size distribution of various materials. Mercury is forced into the voids as a function
of pressure and the volume of the mercury intruded per gram of sample is calculated at
each pressure setting. Total pore volume expressed herein represents the cumulative
volume of mercury intruded at pressures from vacuum to 60,000 psi. Increments in
volume (cm3/g) at each pressure setting are plotted against the pore radius or diameter

corresponding to the pressure setting increments. The peak in the intruded volume versus
pore radius or diameter curve corresponds to the mode in the pore size distribution and
identifies the most common pore size in the sample. Specifically, sample size is adjusted
to achieve a stem volume of 25-75% in a powder penetrometer with a 5 ml bulb and a
stem volume of about 1.1 ml. Samples are evacuated to a pressure of 50 urn of Hg and
held for 5 minutes. Mercury fills the pores from 1.5 to 60,000 psi with a 10 second
equilibrium time at each of approximately 103 data collection points.
Median particle size is determined using a Model LA-930 (or LA-300 or an
equivalent) laser light scattering instrument available from Horiba Instruments,
Boothwyn, Pennsylvania.
Two criteria for describing the tightness of the particle size distribution are particle
size span ratio and beta values as measured using a Horiba laser light scattering
instrument. By "particle size span ratio" it is meant the cumulative diameter of the
particles in the tenth percentile (D10) minus the cumulative volume at the ninetieth
volume percentile (D90) divided by the diameter of the particles in the fiftieth volume
percentile (D50), i.e. (D10-D90)/D50. A lower span ratio indicates a narrower particle
size distribution. By "particle size beta value" it is meant cumulative diameter of the
particles in the twenty-fifth volume percentile (D25) divided by the diameter of the
particles in the seventy-fifth volume percentile (D75), i.e. D25/D75. A higher beta value
indicates a narrower particle size distribution.
CTAB external surface area of silica is determined by absorption of CTAB
(cetyltrimethylammonium bromide) on the silica surface, the excess separated by
centrifugation and determined by titration with sodium lauryl sulfate using a surfactant

electrode. The external surface of the silica is determined from the quantity of CTAB
adsorbed (analysis of CTAB before and after adsorption). Specifically, about 0.5 g of
silica is placed in a 250-ml beaker with 100.00 ml CTAB solution (5.5 g/L), mixed on an
electric stir plate for I hour, then centrifuged for 30 minutes at 10,000 rpm. One ml of
10% Triton X-100 is added to 5 ml of the clear supernatant in a 100-ml beaker. The pH is
adjusted to 3.0-3.5 with 0.1 N HCI and the specimen is titrated with 0.0100 M sodium
lauryl sulfate using a surfactant electrode (Brinkmann SUR150I-DL) to determine the
endpoint.
The % 325 mesh residue of the inventive silica is measured utilizing a U.S.
Standard Sieve No. 325, with 44 micron or 0.0017 inch openings (stainless steel wire
cloth) by weighing a 10.0 gram sample to the nearest 0.1 gram into the cup of the 1 quart
Hamilton mixer Model No. 30, adding approximately 170 ml of distilled or deionized
water and stirring the slurry for at least 7 min. Transfer the mixture onto the 325 mesh
screen; wash out the cup and add washings onto the screen. Adjust water spray to 20 psi
and spray directly on screen for two minutes. (Spray head should be held about four to
six inches above the screen cloth. Wash the residue to one side of the screen and transfer
by washing into an evaporating dish using distilled or deionized water from a washing
bottle. Let stand for two to three minutes and decant the clear water. Dry (convection
oven @ 150°C or under infrared oven for approx. 15 min.) cool and weigh residue on
analytical balance.
Moisture or Loss on Drying (LOD) is the measured silica sample weight loss at
105°C for 2 hours. Loss on ignition (LOI) is the measured silica sample weight loss at
900°C for 2 hours (sample previously predried for 2 hours at 105°C).

The pH values of the reaction mixtures (5 weight % slurry) encountered in the
present invention can be monitored by any conventional pH sensitive electrode.
Sodium sulfate content was measured by conductivity of a known concentration
of silica slurry. Specifically, 38g silica wetcake sample was weighed into a one-quart
mixer cup of a Hamilton Beach Mixer, model Number 30, and 140 ml of deionized water
was added. The slurry was mixed for 5 to 7 minutes, then the slurry was transferred to a
250-ml graduated cylinder and the cylinder filled to the 250-ml mark with deionized
water, using the water to rinse out the mixer cup. The sample was mixed by inverting the
graduated cylinder (covered) several times. A conductivity meter, such as a Cole Palmer
CON 500 Model #19950-00, was used to determine the conductivity of the slurry.
Sodium sulfate content was determined by comparison of the sample conductivity with a
standard curve generated from known method-of-addition sodium sulfate/silica
composition slurries.
Further tests followed below were utilized to analyze the structure of initially
produced silica gel during the overall in situ gel/precipitate production method. Included
within these analyses was porosity. Such a property of accessible porosity was obtained
using nitrogen adsorption-desorption isotherm measurements. The BJH (Barrett-Joiner-
Halender) model average pore diameter was determined based on the desorption branch
utilizing an Accelerated Surface Area and Porosimetry System (ASAP 2010) available
form Micromeritics Instrument Corporation, Norcross, Georgia Samples were out-
gassed at 150-200°C until the vacuum pressure was about 5 µm of Mercury. Such an
analyzer was an automatic volumetric type at 77 K. Pore volume was obtained at a
pressure P/P0=O.99. Average pore diameter is derived from pore volume and surface area

assuming cylindrical pores. Pore size distribution (ΔV/ΔD) was calculated using the BJH
method, which provides the pore volume within a range of pore diameters. A Halsey
thickness curve type was used with pore size range of 1.7 to 300.0 run diameter, with
zero fraction of pores open at both ends.
The toothpaste (dentifrice) viscosity is measured utilizing a Brookfield
Viscometer Model RVT equipped with a Helipath T-F spindle and set to 5 rpm by
measuring the viscosity of the toothpaste at 25°C at three different levels as the spindle
descends through the toothpaste test sample and averaging the results. Brookfield
viscosity is expressed in centipoise (cP).
The Radioactive Dentin Abrasion (RDA) values of dentifrices containing the
silica compositions used in this invention are determined according to the method set
forth by Hefferen, Journal of Dental Res., July-August 1976, 55 (4), pp. 563-573, and
described in Wason U.S. Pat. Nos. 4,340,583,4,420,312 and 4,421,527, which
publications and patents are incorporated herein by reference.
The cleaning property of dentifrice compositions is typically expressed in terms
of Pellicle Cleaning Ratio ("PCR") value. The PCR test measures the ability of a
dentifrice composition to remove pellicle film from a tooth under fixed brushing
conditions. The PCR test is described in "In Vitro Removal of Stain With Dentifrice" G.
K. Stookey, et al., J. Dental Res., 61, 1236-9, 1982. Both PCR and RDA results vary
depending upon the nature and concentration of the components of the dentifrice
composition. PCR and RDA values are unitless.

Preferred Embodiments of the Invention
The inventive materials were prepared by sequentially forming (in situ) a first
silica gel (or gel-like material) and adding thereto sufficient amounts of reactants to form
a precipitated silica component present simultaneously with the initially produced gel (or
gel-like material). The amount of gel is controlled by the quantity of reactants in the first
stage while the amount of precipitated silica is controlled by the quantity of reactants in
the second stage. The structure of the final product is controlled by the amount of gel
first produced as related to the amount of precipitated silica, as well as reaction
parameters, such as temperature, rates, concentrations, pH, and so forth, as discussed in
greater detail above.
Initial Gel Formation
EXAMPLE 1-2
The first two examples show the initial production of silica gel within the overall
gel/precipitate production method. After initial production, some of these samples were
then washed and purified in order to analyze the resultant material to determine if an
actual gel is first formed as well as for other gel properties exhibited by such a sample. It
is important to note that the remainder of the samples was utilized in the further
production of gel/precipitate products below without any washing, purifying, etc.
In each example, a volume of aqueous solution of 3.3 mole ratio sodium silicate
of specified concentration was charged within a 30 gallon reactor and agitated therein at
60 rpm. The reactor contents were then heated to 50°C and then 11.4% sulfuric acid
(heated to 30°C) was added at a specified rate and for a specified time and the resultant

product was then allowed to form into a gel-like material. This material was then filtered
and subsequently washed with water (at about 60°C) and spray-dried. Such collected and
dried material was then tested for a number of properties as noted below, the tests for
which were delineated above. The following Table 1 includes reaction parameters and
conditions; Table 2 provides analyzed properties for these initially produced gel products.
It was evident that, upon analysis, a silica gel material was initially formed. Again, the
filtering and washing steps performed after collection thereof were only necessary to
further analyze the formed gel for certain properties in accordance with Table 2, below.
Such analysis is not generally performed during the actual inventive in situ production of
the target gel/precipitate silica combination. It was merely an interest to determine if a
silica gel had been produced initially and the properties thereof for classification
purposes. Furthermore, for this table as well as throughout this disclosure, any data that
was unavailable or unmeasured is represented by dashes. Additionally, it is important to
note that the oil absorption properties measured for the silica gel alone is not an
indication of nor is it to be confused with the determination of oil absorption for the
entire inventive gel/precipitate silica combination.




In Situ Gel/Precipitate Composite Production
EXAMPLES 3-7
Examples 3-7 contained from about 10 to about 23% by volume gel and thus from
about 90% to about 77% by volume precipitated silica (as noted in the accompanying
tables). The products of these examples had silica structure levels varying from low
structure (LS) to medium structure (MS) to high structure (HS).
A first step was followed in which a volume of aqueous solution of sodium
silicate (Silicate Volume A) of specified concentration (Silicate Concentration A) and a
SiO2:Na2O ratio of 3.3 was charged within a reactor and agitated therein (depending upon
the size of the reactor, the agitation speed was from about 60 to about 92 rpm, although
any speed may be utilized for such a procedure). The reactor contents were heated to
50°C and then 11.4% sulfuric acid was added at a specified rate (Acid Rate A) for a
specified time (Acid Addition Time A). (For Example 5, for instance, the agitator speed
was set to 60 rpm, except it was increased briefly for 1 minute to 120 RPM during Acid
Addition Time 4 -5 minutes.) At this point, a specified Water Volume, if indicated, was
added to the formed silica gel. A silica gel was then visually recognized and the pH of the
slurry was tested and optionally maintained at pH 5.0, as indicated, by adjusting the acid
addition rate. The resultant slurry was then heated to as high as 93 °C (with others heated
to lower temperatures, as low as 80°C, but allowed to continue to heat up to 93°C after
the second stage precipitation was started), and such a temperature was then maintained
for the duration of the batch production. Subsequently, simultaneous addition began of a
second amount of an aqueous solution of sodium silicate pre-heated to 85°C at specified
concentration (Silicate Concentration B) at a specified rate (Silicate Rate B) and the same

sulfuric acid at a specified rate (Acid Rate B). Recirculation of the reactor contents at a
rate of 75 LPM began after simultaneous addition of acid and silicate commenced and
continued through digestion. After a specified time (Silicate Addition Time B) of
sodium silicate introduction, its flow was stopped. The pH of the reactor contents was
continuously monitored during the simultaneous addition stage. The acid addition
continued until the entire batch pH dropped to about 7.0. Once this pH was attained, the
acid flow was slowed to about 2.7 liters per minute and continued at such a rate until the
overall pH of the resultant batch was dropped to 4.6. The finished batch was then heated
at 93°C for 10 minutes (digestion), while maintaining the batch pH at 4.6. The resultant
slurry was then recovered by filtration, washed to a sodium sulfate concentration of less
than about 5% (preferably less than 4%, and most preferably below 2%) as determined by
monitoring the filtrate conductivity and then spray dried to a level of about 5% water
utilizing an inlet temperature of ~480°C. The dried product was then milled to uniform
size. Parameters used for Examples 3-7 are described in Table 3. The Acid rate levels for
some of the examples were adjusted during the reaction, as noted below.





EXAMPLES 8-12
Examples 8-12 contained about 25-35% by volume gel and about 75-65 % by
volume precipitated silica. The products of these examples had silica structure levels
varying from very low structure to high structure. These examples were prepared
according to the procedure given in Example 3-7, except with the parameters described in
Table 5 below (note that Example 12 was produced within a very large reactor, about
40,000 liters in volume, with an agitation speed of about 92 rpm and a high shear
recirculation flow rate of about 3050 liters/minute).




EXAMPLES 13-14
Examples 13-14 contained about 50% gel and about 50% precipitated silica. The
products of these examples had silica structure levels varying from low structure to very
high structure. These examples were prepared according to the procedure given in
Example 3-7, except with the parameters described in Table 7 below.

Several properties of Examples 13-14 were determined according to the methods
described above and the results are summarized in Table 8.


Examples 15-17
Examples 15-17 reflected the ability to adjust the gel level and the silica structure
through pH modifications of the precipitated silica component during gel/precipitate
production as well as through changes in reactant concentrations. These examples were
prepared according to the procedure given in Examples 3-12, except with the parameters

described in Table 9 Below and within the same reactor and under the same agitation
conditions as noted for Example 12, above. Examples 15 and 17 had no high shear
recirculation, however, whereas Example 16 utilized the same high shear recirculation
flow rate as Example 12.

Several properties of Examples 15-17 were determined according to the methods
described above and the results are summarized in Table 10.


Dentifrice Formulations
Toothpaste formulations were prepared using several of the above-described
gel/precipitated silica examples to demonstrate the ready-to-use on demand capabilities
of the inventive compositions without furthering metering of the two components for
optimum dental protection benefits.

To prepare the dentifrices, the glycerin, sodium carboxymethyl cellulose,
polyethylene glycol and sorbitol were mixed together and stirred until the ingrethents
were dissolved to form a first admixture. The deionized water, sodium fluoride,
tetrasodium pyrophosphate and sodium saccharin were also mixed together and stirred
until these ingrethents are dissolved to form a second admixture. These two admixtures
were then combined with stirring. Thereafter, the optional color was added with stirring
to obtain a "pre-mix". The pre-mix was placed in a Ross mixer (Model 130 LDM) and
silica thickener, abrasive silica and titanium dioxide were mixed in without vacuum. A
30-inch vacuum was drawn and the resultant admixture was stirred for approximately 15
minutes. Lastly, sodium lauryl sulfate and flavor were added and the admixture was
stirred for approximately 5 minutes at a reduced mixing speed. The resultant dentifrice
was transferred to plastic laminate toothpaste tubes and stored for future testing. The
dentifrice formulations are given in Table 11 below. The dentifrice formulation utilized
was considered a suitable test dentifrice formulation for the purposes of determining PCR
and RDA (as well as viscosity) measurements for the inventive and comparative cleaning
abrasives. Changes in the amount of carboxymethylcellulose to permit proper formation
of the dentifrice from physical and aesthetic perspectives were made in certain situations
with an offset in the amount of deionized water added, but the overall base dentifrice
formulation remained essentially static for the tests followed as noted above.



A polyethylene glycol available from the Union Carbide Corporation, Danbury,
CT
2 A carboxymethylcellulose available from the Aqualon division of Hercules
Corporation, Wilmington, DE; also acceptable is CEKOL® 2000, a CMC available from
Noviant
The dentifrice formulations prepared above were evaluated for PCR and RDA
properties, according to the methods described above; the measurements, as well as the
PCR:RDA ratios for each dentifrice formulation are provided in Table 12 below. The
PCR data for Formulations 1,3, and 8 were obtained from Southeastern Dental Research
Corporation of Port Allen, Lousiana, and the remaining PCR data from Oral Health
Research Institute of Indianapolis, Indiana.

The results show varied performance with highly effective cleaning capabilities
with relatively low dentin abrasion properties.
Several other dentifrice formulations were prepared using a combination of 2
inventive silicas for Formulations 12-14 and a combination of an inventive silica and a
commercial silica (ZEODENT® 115 from J.M. Huber Corporation) for Formulation 11.
The dentifrice formulations were prepared according to the method provided above and

with much the same ingrethents as described above in Table 11. The following Table 13
provides the formulas for these toothpastes incorporating blends of different silica
abrasives in relation to the invention described herein.


The "dentifrice formulations prepared above were evaluated for PCR and RDA
properties, according to the methods described above; the measurements, as well as the
PCR:RDA ratios for each dentifrice formulation are provided in Table 14 below.

The cleaning ability of these combinations, in particular Formulas 12,13, and 14,
evince a highly surprising and effective dental polishing and film removal material with
much lower abrasion levels.
Detailed Description of the Drawings
FIG. 1 shows in graphical representation the ratios of RDA and PCR available
within some of the dentifrice formulations listed above, as compared with physical
mixtures of silica gel and precipitated silica, produced in much the same way as those
disclosed within U.S. Pat. No. 5,658,553 to Rice. The slope of each line indicates the
general results accorded by each different formulation and shows that the simultaneously
formed combination of this invention imparts greater PCR results with correlated lower
RDA- Thus, it has been unexpectedly found that such an inventive combination permits
greater cleaning ability without simultaneously unacceptably high dentin abrasion.

All dentifrices exhibited acceptable viscosity, fluoride availability, and excellent
aesthetics (stand-up, texture, dispersion). Particularly, in view of the graphical
representation within FIG. 1, it is evident that the comparative physical blends of such
materials do not exhibit the same desired increase in pellicle film cleaning efficiency with
lower RDA values as those of the in situ generated invention combinations.
Likewise, in FIG. 2 there is provided a comparison of the thickening capabilities
of the inventive in situ silica combinations versus those physical blends of gels and
precipitates described within the Rice patent (within the same test dentifrice formulation
as listed above). It is evident that there is a significant difference in overall structure and
resultant function of these different types of materials as the in situ generated composite
materials exhibit differing degrees of thickening over the spectrum of amounts of
gel/precipitate present therein than the Rice patent blends. Clearly, then, there is a
distinction in form and characteristics for these two different types of dentifrice additives.
Furthermore, FIG. 3 shows in graphical representation the measurements of the
PCR vs. RDA readings for the inventive gel/precipitate composite materials over a wide
range as compared with the same measurements for the conventional precipitated silica
abrasives (again as measured within the same test dentifrice formulation as presented
above). It is evident from this representation that the inventive gel/precipitate silica
composite materials accord much higher PCR results with correlative lower RDA
properties than the conventional abrasive materials, showing the significant differences
between the comparative abrasives and the inventive in situ produced types. In this
manner, surprisingly, it has been realized that the in situ production of blends of silica
gels and precipitated silica materials provides improved pellicle film cleaning benefits

while simultaneously exhibiting much lower dentin abrasion readings, thereby providing
a more effective cleaning material with a lower propensity to deleteriously abrade tooth
surfaces during use.
While the invention will be described and disclosed in connection with certain
preferred embodiments and practices, it is in no way intended to limit the invention to
those specific embodiments, rather it is intended to cover equivalent structures structural
equivalents and all alternative embodiments and modifications as may be defined by the
scope of the appended claims and equivalence thereto.

WE CLAIM:
1. An abrasive gel/precipitate silica composite, said composite produced by the method
comprising the sequential steps of a) admixing a sufficient amount of an alkali silicate and an
acidulating agent together to form a composition comprising silica gel particles; and, without
first washing or purifying said formed composition comprising silica gel particles, b)
subsequently introducing to said composition comprising silica gel particles a sufficient
amount of an alkali silicate and an acidulating agent to form a precipitated silica, thereby
producing said abrasive gel/precipitate silica composite; wherein said composite exhibits a
radioactive dentin abrasion (RDA) measurement from 180 to 240 and a pellice cleaning ratio
(PCR) measurement of from 90 to 160.
2. The abrasive gel/precipitate silica composite as claimed in claim 1 wherein said
composite is in the form of particles exhibiting a median particle size range of from 3 to 20
microns.
3. A dentifrice formulation comprising the abrasive gel/precipitate silica composite as
claimed in claim 1.
4. The dentifrice formulation as claimed in claim 3 wherein said formulation comprises
an abrasive component different from said abrasive gel/precipitate silica composite.
5. A dentifrice formulation comprising the abrasive gel/precipitate silica composite as
claimed in claim 2.
6. The dentifrice formulation as claimed in claim 5 wherein said formulation comprises
an abrasive component different from said abrasive gel/precipitate silica composite.

7. An abrasive gel/precipitate silica composite, said composite produced by the method
comprising the sequential steps of a) admixing a sufficient amount of an alkali silicate and an
acidulating agent together to form a composition comprising silica gel particles; and, without
first washing or purifying said formed composition comprising silica gel particles, b)
subsequently introducing to said composition comprising silica gel particles a sufficient
amount of an alkali silicate and an acidulating agent to form a precipitated silica, thereby
producing said abrasive gel/precipitate silica composite; wherein said composite exhibits a
RDA measurement from 95 to 150 and a PCR measurement of from 90 to 120.
8. The abrasive gel/precipitate silica composite as claimed in claim 7 wherein said
composite is in the form of particles exhibiting a median particle size range of from 3 to 20
microns.
9. A dentifrice formulation comprising the abrasive gel/precipitate silica composite as
claimed in claim 7.
10. The dentifrice formulation as claimed in claim 9 wherein said formulation comprises
an abrasive component different from said abrasive gel/precipitate silica composite.
11. A dentifrice formulation comprising the abrasive gel/precipitate silica composite as
claimed in claim 8.
12. The dentifrice formulation as claimed in claim 11 wherein said formulation comprises
an abrasive component different from said abrasive gel/precipitate silica composite.
13. A thickening and abrasive gel/precipitate silica composite, said composite produced
by the method comprising the sequential steps of a) admixing a sufficient amount of an alkali
silicate and an acidulating agent together to form a composition comprising silica gel

particles; and, without first washing or purifying said formed composition comprising silica
gel particles, b) subsequently introducing to said composition comprising silica gel particles
a sufficient amount of an alkali silicate and an acidulating agent to form a precipitated silica,
thereby producing said abrasive gel/precipitate silica composite; wherein said composite
exhibits a RDA measurement from 20 to 80 and a PCR measurement of from 50 to 80.
14. The thickening and abrasive gel/precipitate silica composite as claimed in claim 13
wherein said composite is in the form of particles exhibiting a median particle size range of
from 3 to 20 microns.
15. A dentifrice formulation comprising the thickening and abrasive gel/precipitate silica
composite as claimed in claim 13.
16. The dentifrice formulation as claimed in claim 15 wherein said formulation comprises
an abrasive component different from said thickening and abrasive gel/precipitate silica
composite.
17. A dentifrice formulation comprising the thickening and abrasive gel/precipitate silica
composite as claimed in claim 14.
18. The dentifrice formulation as claimed in claim 17 wherein said formulation comprises
an abrasive component different from said thickening and abrasive gel/precipitate silica
composite.


ABSTRACT

HIGH-CLEANING SILICA MATERIALS
AND DENTRTFICE CONTAINING SUCH
Unique abrasive and/or thickening materials that are in situ generated compositions of
precipitated silicas and silica gels are provided. Such compositions exhibit different
beneficial characteristics depending on the structure of the composite in situ generated
material. With low structured composites (as measured via linseed oil absorption levels from
40 to 100 ml oil absorbed/100 g composite), simultaneously high pellicle film cleaning
properties and moderate dentin abrasion levels are possible in order to accord the user a
dentifrice that effectively cleans tooth surfaces without detrimentally abrading such surfaces.
Increased amounts of high structure composite materials tend to accord greater viscosity
build and thickening benefits together with such desirable abrasion and cleaning properties,
albeit to a lesser extent than for the low structure types. Thus, mid-range cleaning materials
will exhibit oil absorption levels from an excess of 100 to 150, and high thickening/low
abrasion composite exhibit oil absorption properties in excess of 150. Such an in situ,
simultaneously produced precipitated silica/silica gel combination provides such
unexpectedly effective low abrasion and high cleaning capability and different thickening
characteristics as compared to physical mixtures of such components. A method for making
such gel/precipitated silica composite materials is also disclosed.

Documents:

02061-kolnp-2007-abstract.pdf

02061-kolnp-2007-assignment.pdf

02061-kolnp-2007-claims.pdf

02061-kolnp-2007-correspondence others 1.1.pdf

02061-kolnp-2007-correspondence others.pdf

02061-kolnp-2007-description complete.pdf

02061-kolnp-2007-drawings.pdf

02061-kolnp-2007-form 1.pdf

02061-kolnp-2007-form 3.pdf

02061-kolnp-2007-form 5.pdf

02061-kolnp-2007-gpa.pdf

02061-kolnp-2007-international publication.pdf

02061-kolnp-2007-international search report.pdf

02061-kolnp-2007-pct request form.pdf

02061-kolnp-2007-priority document.pdf

2061-KOLNP-2007-(28-10-2011)-CORRESPONDENCE.pdf

2061-KOLNP-2007-ABSTRACT-1.1.pdf

2061-KOLNP-2007-AMANDED CLAIMS.pdf

2061-KOLNP-2007-ASSIGNMENT.pdf

2061-KOLNP-2007-CORRESPONDENCE 1.2.pdf

2061-KOLNP-2007-CORRESPONDENCE-1.1.pdf

2061-KOLNP-2007-DRAWINGS-1.1.pdf

2061-KOLNP-2007-EXAMINATION REPORT.pdf

2061-KOLNP-2007-FORM 1-1.1.pdf

2061-KOLNP-2007-FORM 13 1.2.pdf

2061-KOLNP-2007-FORM 13-1.1.pdf

2061-KOLNP-2007-FORM 13.pdf

2061-KOLNP-2007-FORM 18.pdf

2061-KOLNP-2007-FORM 2.pdf

2061-KOLNP-2007-FORM 3 1.1.pdf

2061-KOLNP-2007-FORM 5.pdf

2061-KOLNP-2007-FORM3.pdf

2061-KOLNP-2007-GPA.pdf

2061-KOLNP-2007-GRANTED-ABSTRACT.pdf

2061-KOLNP-2007-GRANTED-CLAIMS.pdf

2061-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

2061-KOLNP-2007-GRANTED-DRAWINGS.pdf

2061-KOLNP-2007-GRANTED-FORM 1.pdf

2061-KOLNP-2007-GRANTED-FORM 2.pdf

2061-KOLNP-2007-GRANTED-SPECIFICATION.pdf

2061-KOLNP-2007-OTHERS 1.2.pdf

2061-KOLNP-2007-OTHERS-1.1.pdf

2061-KOLNP-2007-PA.pdf

2061-KOLNP-2007-PETITION UNDER RULE 137.pdf

2061-KOLNP-2007-REPLY TO EXAMINATION REPORT.pdf


Patent Number 253380
Indian Patent Application Number 2061/KOLNP/2007
PG Journal Number 29/2012
Publication Date 20-Jul-2012
Grant Date 17-Jul-2012
Date of Filing 06-Jun-2007
Name of Patentee J. M. HUBER CORPORATION
Applicant Address 333, THORNALL STREET, EDISON, NJ
Inventors:
# Inventor's Name Inventor's Address
1 MCGILL, PATRICK, D. 2215, PRICE ROAD, DARLINGTON, MD 21034
2 FULTZ, WILLIAM, C. 1114, TELEGRAPH ROAD, RISING SUN, MD 21911
PCT International Classification Number C01B 33/12,A61K 8/18
PCT International Application Number PCT/US2005/036173
PCT International Filing date 2005-10-06
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/996,538 2004-11-24 U.S.A.