Title of Invention


Abstract A thermoplastic additive composition comprising at least one anticaking agent component selected from the group consisting of silica gel, talc, dihydrotalcite, metal carboxylic acids, and any mixtures thereof, and at least one nucleating compound conforming to the structure of Formula (I) wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are as defined in the specification and claims; wherein the anticaking agent and nucleating compound are present in the composition in a weight ratio of anticaking agent to nucleating compound of from about 10:90 to about 30:70.
Full Text Field of the Invention
This invention relates to milled, small particle size, solid bicyclo[2.2.1]heptane dicarboxylate salt-containing thermoplastic nucleating additive formulations further comprising at least one anticaking agent for improved haze reduction, improved nucleation performance, and prevention of potential cementation (via agglomeration) of the salt component present therein. Such small particle size dicarboxylate salts provide desirable properties within thermoplastic articles, particularly as nucleating agents, but apparently suffer from certain clarity issues and agglomeration problems (due to the fiat and thin plate structures of such compounds and the propensity they exhibit to cohere to each other during storage), making utilization thereof less desirable for certain applications. Thus, an improvement has been provided to permit full benefit of the excellent crystallization temperatures, stiffness, and calcium stearate compatibility such dicarboxylate salts accord within target low haze thermoplastics. Furthermore, unexpected improvements in dusting reduction have been found upon the utilization of such anticaking additives in combination with the aforementioned nucleating salts. Thermoplastic additive compositions and methods of producing thermoplastics with such nucleator/anticaking additive combinations are also contemplated within this invention.
Background of the Prior Art
All U.S. patents cited below are herein entirely incorporated by reference.
As used herein, the term "thermoplastic" is intended to mean a polymeric material that will melt upon exposure to sufficient heat but will retain its solidified state, but not prior shape without use of a mold or like article, upon sufficient cooling. Specifically, as well, such a term is intended solely to encompass polymers meeting such a broad definition that also exhibit either crystalline or semi-crystalline morphology upon cooling after melt-formation through the use of the aforementioned mold or like article. Particular types of polymers contemplated within such a definition include, without limitation, polyolefins (such as polyethylene, polypropylene, polybutylene, and any combination thereof), polyamides (such as nylon), polyuretlianes, polyester (such as polyethylene terephthalate), and the like (as
well as any combinations thereof).
Thermoplastics have been utilized in a variety of end-use applications, including
storage containers, medical devices, food packages, plastic tubes and pipes, shelving units,
and the like. Such base compositions, however, must exhibit certain physical characteristics
in order to permit widespread use. Specifically within polyolefins, for example, uniformity in
arrangement of crystals upon crystallization is a necessity to provide an effective, durable,
and versatile polyolefin article, hi order to achieve such desirable physical properties, it has
been known mat certain compounds and compositions provide nucleation sites for polyolefin
crystal growth during molding or fabrication. Generally, .compositions containing such
nucleating compounds crystallize at a much faster rate than un-nucleated polyolefin. Such
crystallization at higher temperatures results in reduced fabrication cycle times and a variety
of improvements in physical properties, such as, as one example, stiffness.
Such compounds and compositions that provide faster and or higher polymer
crystallization temperatures are thus popularly known as nucleators. Such compounds are, as
their name suggests, utilized to provide nucleation sites for crystal growth during cooling of a
thennoplastic molten formulation. Generally, the presence of such nucleation sites results in
a larger number of smaller crystals. As a result of the smaller crystals formed therein,
clarification of the target thennoplastic may also be achieved, although excellent clarity is not
always a result. The smaller crystal size, the less light is scattered, hi such a manner, the
clarity of the thennoplastic article itself can be improved. Thus, thennoplastic nucleator
compounds are very important to the thermoplastic industry in order to provide enhanced
clarity, physical properties and/or faster processing.
The most effective thermoplastic nucleator in terms of high crystallization
temperatures is available from Milliken & Company under the tradename of HPN-68. Other
like thermoplastic nucleating compounds are disclosed within U.S. Pat. Nos. 6,465,551 and
6,534,574, both entirely incorporated herein by reference. The HPN-68 compound is
disodium bicyclo[2.2. IJheptanedicarboxylate. Other thermoplastic nucleating agents that
sxhibit appreciably lower crystallization temperatures include dibenzylidene sorbitol
compounds, such as l,3-0-2,4-bis(3,4-dimethylbenzylidene) sorbitol (hereinafter DMDBS),
available from Milliken & Company under the trade name Millad® 3988, sodium benzoate,
sodium 2,2'-methylene-bis-(4,6-di-tert-butylphenyl) phosphate (from Asahi Denka Kogyo
K.K., known as NA-11), talc, cyclic bis-phenol phosphates (such as NA-21, also available
from Asahi Denka), and, as taught within Patent Cooperation Treaty Application WO
98/29494, to Minnesota Mining and Manufacturing, the unsaturated compound of disodium
bicyclo[2.2. Ijheptene dicarboxylate. Such compounds all impart relatively high polyolefm
crystallization temperatures; however, each also exhibits its own drawback for large-scale
industrial applications, and none can match the effectiveness of the above-noted saturated
Some of the above-noted nucleating agents also provide clarifying properties within
certain thermoplastics, such as polypropylene (Millad® 3988, for example, and to a lesser
extent, NA-21), Such clarification capabilities coupled with high peak crystallization
temperatures are highly desired. For certain end-uses, at least a maximum level of haze (for
instance, 35%) is acceptable. The previously listed dicarboxylate salt nucleating agents
unfortunately exhibit relatively high haze levels within polypropylene, although such
compounds also provide excellent calcium stearate compatibility, increased stiffness within
target thermoplastic articles, and certain degrees of hygroscopicity. Thus, such compounds
provide extremely desirable qualities and benefits within target thermoplastics.
Unfortunately, as noted above, haze problems have limited the usefulness of such nucleating
agents within certain target end-uses, even though the crystallization temperatures imparted
thereby are extremely high.
To remedy this initial problem, haze reduction has been achieved when such saturated
dicarboxylate salts have been either spray dried to fonn relatively large particles, or jet-milled
for substantially uniform small particle sizes (from 2.5-4.5 micrometers in length). However,
it has unfortunately been noticed that upon producing such small particle size compounds,
there is a tendency for the compounds to suffer from stacking and eventual agglomeration
(which inevitably leads to cementation of the stored solid compounds), thus deleteriously
affecting the ability to actually disperse, if not use altogether, such compounds in
thermoplastic media. Additionally, during storage such compounds exhibit "growth" due to
such agglomeration as well within the packaging container such that it has been noticed on
regular occasions that the storage container itself becomes ruptured and/or damaged and the
nucleator powders leak therefrom or it becomes very difficult to remove the cemented
product therefrom. These problems are most likely due to the plate-like structures such
(•compounds exhibit coupled with exposure to moisture and/or humidity. Unlike cubic,
spherical, or other like geometric shapes, such plate-like configurations are highly susceptible
to the aforementioned stacking problem. When such occurs, particularly in air jet-milled or
spray dried, substantially uniform small particle-size samples, it has been realized that even a
small amount of moisture can lead to molecular attraction between two plate-like structures
thereof. Upon bonding, the ability to separate such structures is extremely difficult. Upon
stacking of a larger number of such structures, cementation and "growth" (increase in volume
within a closed space) may occur, thereby preventing use thereof of the particular sample
and/or resulting in difficulties with storage within tightly sealed containers. Furthermore, it
has been found in some circumstances that such cemented samples are bonded to such a
degree that separation is, for the most part, impossible. Unless such small particles can
actually be added and dispersed within target prepolymer media, the benefits of nucleation
and possible clarification are simply unavailable. Thus, this cementation problem prevents
effective utilization of such an excellent thermoplastic nucleating agent, especially for
purposes of imparting lower haze levels.
As such, there is a definite need to prevent plate-to-plate interactions of individual
saturated dicarboxylate salt thermoplastic nucleating agents, particularly during production,
storage, and incorporation within target thermoplastic media. In such a manner, it is
theorized that the substantially uniform small particle-sized compounds could then impart the
desired lower haze levels than for the larger and/or nonuniform particle size compound
formulations. Without such needed remedies, the ability to utilize such an extremely
effective and efficacious thermoplastic nucleating agent is limited to opaque end-uses.
Objects and Detailed Description of the Invention
Therefore, an object of the invention is to provide a jet-milled or spray dried, small
particle-size polyolefin nucleating formulation, including saturated dicarboxylate salts, that
imp aits exceptional nucleation efficacy, as indicated by very high polymer peak
crystallization temperatures within polyolefin articles, as well as improved clarification
capabilities within polypropylene. Another objective of this invention is to provide
formulations that exhibit extremely low hygroscopicity in order to accord an extremely good
shelf-stable additive composition. Yet another object of this invention is to provide a
saturated bicyclic nucleator compound-containing powder formulation that does not exhibit
deleterious cementation (compaction) and/or growth (volume increase) during long-term
storage. A further object of this invention is to provide optimum performance of the
nucleating salt compound within target thermoplastics under non-ideal mixing and
compounding conditions. Additionally, it is an object of this invention to provide
thermoplastic nucleating compositions that may be used in various polyolefin media for use
in myriad end-uses, particularly within applications that require haze measurements of midrange
Accordingly, this invention encompasses a thermoplastic additive composition
comprising at least one anticaking compound or composition and at least one saturated metal
or organic salts of bicyclic dicarboxylates, preferably saturated metal or organic salts of
bicyclic dicarboxylates, preferably, bicyclo[2.2.1]heptane-dicarboxylates, or, generally,
compounds conforming to Formula (I)
(Figure Removed)
wherein RI, R2, R-3, R4, RS, R6, R7, RS, Rg, and R10 are individually selected from the group
consisting of hydro gen, C1-C9 allcyl, hydroxy, C1-C9 alkoxy, C1-C9allcyleneoxy, amine, and
C1-C9alkylamine, halogen, phenyl, alkylphenyl, and geminal or vicinal carbocyclic having up
to nine carbon atoms, R' and R" are the same or different and are individually selected from
the group consisting of hydrogen, C1-C9 allcyl, hydroxy, amine, polyamine, polyoxyamine,
C1-C9 alkylamine, phenyl, halogen, C1-C30 allcoxy, C1-C30 polyoxyaUcyl, C(0)-NRnC(0)0-
R'", and C(0)O-R"', wherein Rn is selected from the group consisting of C1-C30allcyl,
hydrogen, CfCao alkoxy, and C1-C30 polyoxyallcyl, and wherein R'" is selected from the
group consisting of hydrogen, a metal ion (such as, without limitation, Na1", K+, Li+,Ag+ and
any other monovalent ions), an organic cation (such as ammonium as one non-limiting
> example), polyoxy-C1-C30-alkylene, C1-C30alkyl,C1-C30 alkylene, C1-C30 allcyleueoxy, a
steroid moiety (for example, cholesterol), phenyl, polyphenyl, Ci-Cao allcylhalide, and CC1-C30
alkylamine; wherein at least one of R' andR" is either C(O)-NRHC(0)O-R'" or C(0)0-R"',
wherein if both R' and R" are C(0)0-R'" then R'" both R' and R" may be combined into a
single bivalent metal ion (such as Ca2+, as one non-limiting example) or a single trivalent
metal overbase (such as Al-OH, for one non-limiting example). Preferably, R' and R" are the
same and R"' is either Na+ or combined together for both R' and R" and Ca24'. Other possible
compounds are discussed in the preferred embodiment section below.
Preferably, as noted above, such a compound conforms to the structure of Formula (IT)
(Figure Removed)
wherein MI and M.2 are the same or different and are independently selected from the group
consisting of metal or organic cations or the two metal ions are unified into a single metal ion
(bivalent, for instance, such as calcium, for example), and RI, R2, Ra, R-4, RS, Re, R?, Rg, RO,
and RIO are individually selected from the group consisting of hydrogen, d-Cg alkyl,
hydroxy, C]-Cg alkoxy, C|-C9 alkyleneoxy, amine, and Ci-Cg allcylamine, halogen, phenyl,
alkylphenyl, and geniinal or vicinal carbocyclic having up to 9 carbon atoms. Preferably, the
metal cations are selected from the group consisting of calcium, strontium, barium,
magnesium, aluminum, silver, sodium, lithium, rubidium, potassium, and the like. Within
that scope, group I and group n metal ions are generally preferred. Among the group I and II
cations, sodium., potassium, calcium and strontium are preferred, wherein sodium and
calcium are most preferred. Furthermore, the MI and MT groups may also be combined to
form a single metal cation (such as calcium, strontium, barium, magnesium, aluminum,
, including monobasic aluminum, and the Like). Although this invention encompasses all
stereochemical configurations of such compounds, the cis configuration is preferred wherein
cis-endo is the most preferred embodiment. The preferred embodiment polyolefin articles
and additive compositions for polyolefin formulations comprising at least one of such
compounds, broadly stated as saturated bicyclic carboxylate salts, are also encompassed
within this invention.
As noted above, in order to develop a proper polyolefin nucleator compound or
composition for industrial applications, a number of important criteria needed to be met. The
inventive nucleating agents meet all of these important requirements very well. For instance,
as discussed in greater detail below, these inventive salts provide excellent high peak
crystallization temperatures in a variety of polyolefin formulations, particularly within
random copolymer polypropylene (hereinafter RCP), impact copolymer polypropylene
(hereinafter ICP), and homopolymer polypropylene (hereinafter HP). As a result, such
inventive salts provide excellent mechanical properties for polyolefin articles without the
need for extra fillers and rigidifying additives, and desirable processing characteristics such as
improved (shorter) cycle time. The salts also do not interact deleteriously with calcium
stearate additives.
The mere inclusion of an anticaking compound within a formulation of such a bicyclic
nucleator compound is sufficient and considered inventive to prevent deleterious cementation
and growth results during storage. In such a situation, the particle sizes of such nucleators
may be of any range. However, in terms of improving haze and peak crystallization
temperature properties within thermoplastics in which such a nucleator is added, the presence
of an anticakiug agent is helpful, but primarily when the nucleator compound exhibits a
relatively small particle size. As noted below, the introduction of nucleator compounds either
i) that exhibit mean particle sizes of a D95 (defined below) of at most about 10 microns
and/or a MVD (also defined below) of at most 7.5, or ii) that have been high intensity-mixed
and blended with either the anticaking agent simultaneously or within the target resin with the
anticaking agent present. In either case, it is believed, without intending on limiting the
invention, or being bound by any specific scientific principles or theories, that the nucleator
compounds are reduced in particle size to such an extent as to improve the dispersion thereof
within the target resin. The anticaking agent appears to prevent agglomeration during storage
as well as during mixing, blending, and resin production to provide more reliable' dispersion
of non-agglomerating nucleator compounds as a result as well. Thus, no specific particle size
range is required of the nucleator compounds during production of thermoplastics therewith,
only the option of such a range or the equivalent of any high intensity-mixing step to, in
essence, grind the nucleator compounds to smaller particle sizes prior to incorporation within
molten resins simultaneously with the necessarily present anticaking agent(s). Thus, for
purposes of this invention, the term "small particle size nucleator compound" is intended to
indicate either a maximum particle size as noted above or high intensity-mixing (or
equivalent) thereof.
As noted above, the target formulations for introduction of such novel nucleating
agents are thermoplastics, or more specifically, polyolefins. Such formulations may be
utilized in myriad different end-uses, including without limitation, such broadly considered
groups as fibers, thin film or thin-walled articles (e.g., pliable wrappers, thin-walled drinking
cups, etc., having thicknesses between 0.1 and 15 mils, for example), thicker plaque or other
like solid articles (e.g., from 15 to 150 mils in thickness), and even thicker-walled articles
(e.g., greater than 150 mils thickness). Individual types of each group include, again, without
limitation, either as complete articles, or as components of articles, the following:
a) fibers: spun and nonwoven polyolefin, polyamide, polyaramid, and the like, fibers of
any denier measurement, as well as blends with other synthetic or natural fibers (e.g., cotton,
ramie, wool, and the like); b) thin film articles: cast firms, candy wrappers, package wrappers
(e.g., cigarette box wrappers, for example), and other like blown, extruded, or other similar
type of film application, as well as thin-walled articles, such as drinking cups, thin containers,
coverings, and the like; c) thicker plaque or other like solid articles: deli containers, water
cups, cooler linings, syringes, labware, medical equipment, pipes, tubes, urinanalysis cups,
intravenous bags, food storage containers, waste containers, cooler housings, automotive
instrument panels, flower pots, planters, office storage articles, desk storage articles,
disposable packaging (e.g., reheatable food containers, either thermofonned or thin-walled or
high speed injection molded types), and the like; and d) even thicker-walled articles: i)
automotive applications, such as door panels, instrument panels, body panels, fan covers,
steering wheels, bumper fascia, fan shields, radiator shields, automotive fluid containers,
battery cases, storage compartments, and the like; ii) large appliances, such as refrigerator
linings, refrigerator parts (e.g., shelves, ice machine housings, door handles, and the like),
dishwasher linings, dishwasher parts (e.g., racks, pipes, tubes, doorhandles, liquid and/or
solid detergent storage compartments), washing machine drums, washing machine agitators,
and the like; iii) small appliances, such as blender housings, blender containers, toaster oven
housings, toaster oven handles, coffee pots, coffee pot housings, coffee pot handles, food
processors, hair dryers, can openers, and the like; iv) housewares, such as large storage totes,
large storage containers, lids for either such totes or containers, waste baskets, laundry
baskets, shelves, coolers, and the like; v) consumer products, such as furniture (e.g., small
chairs, tables, and the like), toys, sporting goods, disposable packaging (e.g., reheatable food
containers), compact disc cases, DVD cases, CD-ROM cases, floppy disc containers, floppy
disc housings, VHS tape cases, VHS tape housings, flower pots, planters, clothes hangers,
lawn accessories (e.g., lawn tools, and the like), garden accessories (e.g., garden implements),
lawn mower housings, fuel containers, pipes, tubes, hoses, tool boxes, tackle boxes, luggage,
conduits, lawn trimmer housings, large trash cans, infant car seats, infant chairs (e.g., for
dining tables), and the like.
The term polyolefin or polyolefin resin is intended to encompass any materials
comprised of at least one polyolefin compound. Preferred examples include isotactic and
syndiotactic polypropylene, polyethylene, poly(4-methyl)pentene, polybutylene, and any
blends or copolymers thereof, whether high or low density in composition. The polyolefin
polymers of the present invention may include aliphatic polyolefins and copolymers made
from at least one aliphatic olefin and one or more ethylenically unsaturated co-monomers.
Generally, the co-monomers, if present, will be provided in a minor amount, e.g., about
percent or less or even about 5 percent or less, based upon the weight of the polyolefin (e.g.
random copolymer polypropylene), but copolymers containing up to 25% or more of the comonomer
(e.g., impact copolymers) are also envisaged. Other polymers or rubber (such as
EPDM or EPR) may also be compounded with the polyolefin to obtain the aforementioned
characteristics. Such co-monomers may serve to assist in clarity improvement of the
polyolefin, or they may function to improve other properties of the polymer. Other examples
include acrylic acid and vinyl acetate, and the like. Examples of olefin polymers whose
transparency can be improved conveniently according to the present invention are polymers
and copolymers of aliphatic monoolefins containing 2 to about 6 carbon atoms which have an
average molecular weight of from about 10,000 to about 2,000,000, preferably from about
30,000 to about 300,000, such as, without limitation, polyethylene, linear low density
polyethylene, isotactic polypropylene, syndiotactic polypropylene, crystalline
ethylenepropylene copolymer, poly(l-butene), polymethylpentene, 1-hexene, 1-octene, and
vinyl cyclohexane. The polyolefins of the present invention may be described as basically
linear, regular polymers that may optionally contain side chains such as are found, for
instance, in conventional low density polyethylene.
Although polyolefins are preferred, the nucleating agents of the present invention are
not restricted to polyolefins, and may also give beneficial nucleation properties to polyesters
such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), and polyethylene
naphthalate (PEN), as well as polyamides such as Nylon 6, Nylon 6,6, and others. Generally,
any thermoplastic composition having some crystalline content may be improved with the
nucleating agents of the present invention.
The compositions of the present invention may be obtained by adding the
aforementioned anticaking additive plus saturated bicyclic dicarboxylic salt (or combination
of salts or composition comprising such salts) formulation to the thermoplastic polymer or
copolymer and merely mixing the resultant composition by any suitable means. Generally,
commercial production methods utilize low-intensity mixing procedures for both blending
additives together, as well as polymer components and additives. On some occasions, highintensity
is employed, and may be desirable, for these purposes. For the purposes of this
invention, examples utilizing both types of mixing procedures for the additive and/or polymer
plus additives blending methods were produced and tested.
Alternatively, a concentrate containing as much as about 20 percent by weight of the
potentially preferred saturated [2.2.1] salt in a polyolefin masterbatch comprising the required
acid scavenger may be prepared and be subsequently mixed with the target resin.
Furthermore, the inventive compositions (with other additives potentially) may be present in
any type of standard thermoplastic (e.g., polyolefin, most preferably) additive form, including,
without limitation, powder, prill, agglomerate, liquid suspension, and the like, particularly
comprising dispersion aids such as polyolefin (e.g., polyethylene) waxes, stearate esters of
glycerin, montan waxes, mineral oil, and the like. Basically, any form may be exhibited by
such a combination or composition including such combination made from blending,
agglomeration, compaction, and/or extrusion.
Another alternative method of utilizing such a combination of components involves
the initial addition of from 0.1 to 5% by weight of the anticaking agent to the bicyclic
nucleator formulation- It has been found that for storage purposes, this low amount of
anticaking additive provides the desired effect of preventing agglomeration and ultimate
cementation. Subsequently, then, a larger amount of anticaking agent in the range of from
10-20% by weight, for instance, may be added to a bicyclic nucleator formulation during
introduction within a target molten thermoplastic. As noted above, the high amount of
anticaking agent appears to contribute to the ability of the bicyclic nucleator to impart higher
crystallization temperatures and simultaneous lower haze measurements to such target
thermoplastics. Thus, instead of relying upon inclusion of large amounts of anticaking agents
during initial bicyclic nucleator storage, it is thus possible to delay addition of such large
amounts, thereby permitting an optimization of greater amounts of the nucleator compound to
be stored at the highest available level of anticaking (anti-agglomeration, anticementation,
etc.), without needing to include larger amounts of such agents that would not contribute any
farther reductions in cementation propensities during storage.
The target thermoplastic composition may then be processed and fabricated by any
number of different techniques, including, without limitation, injection molding, injection
blow molding, injection stretch blow molding, injection rotational molding, extrusion,
extrusion blow molding, sheet extrusion, film extrusion, cast film extrusion, foam extrusion,
theimoforrning (such as into firms, blown-films, biaxially oriented films), thin wall injection
molding, and the like, into a fabricated article.
The term anticaking agent is intended to encompass compounds and compositions that
impart effective prevention of stacking and agglomeration within powders of the bicyclic
nucleators defined in Figures (I) and (IT), above, such that compaction and growth of stored
powders of such type are minimal at worst, and nonexistent preferably. Thus, compaction
properties such that a metal rod can be depressed though to the bottom of a glass vial (the
protocol described in greater detail below) and an increase in volume of a sample powder of
at most 5% of the initial measurement within the "long-term elevated temperature and
humidity storage test" (again, outlined in greater detail below), preferably exhibiting no
volume increase at all, properly defines the compounds intended to be within the scope of the
term "anticaking agent" for purposes of this invention. In the presence of such agents, the
preferred saturated dicarboxylate salt nucleator compounds are prevented from interacting
and cohering together due to the ability for such agents to easily arrange themselves between
plates of such salt compounds. Thereby, cementation is prevented, and volume expansion
(growth) is reduced (since propensity of interaction of like charged compounds is diminished
as well). The presence of such a component appears to facilitate clarification to the resultant
thermoplastic (preferably, polypropylene) with simultaneous higher crystallization
temperatures. Such a result is highly unexpected, although extremely useful. Particular
anti caking agents useful include silica gels and treated silica gels (such as the silica gels
available from W.R. Grace Company under the txadename SYLOBLOC®), talc,
dihydrotalcites (DHT-4A, for example, from Mitsui Chemicals), calcium stearate, and any
other type of compound or composition that effectively prevents plate-to-plate interactions
between the aforementioned nucleator compounds (bicyclic dicarboxylate salts), particularly
those compounds and/or compositions that also exhibit an electrical charge opposite that of
the nucleating salt itself (thereby permitting reduced propensity for dusting and/or growth).
Other examples may be found within US Pat Nos. 5,728,742 and 4,734,478; such references
fail to teach the combination of nucleators with such agents, only the presence of such
compounds within water-soluble polymers themselves to prevent caking of such materials.
Air-jet milling of the bicyclic nucleator together with the anticaking agent has
surprisingly been found to impart the aforementioned lower haze/increased peak
crystallization temperature for target thermoplastic articles. There has been no discussion of
any such procedure being followed within polymeric articles, let alone thermoplastics. The
particle size of the final air-jet milled product (made from a mix of powders of the two
components that are air-jet milled simultaneously) is thus of relative importance to impart the
best overall haze and peak crystallization temperatures within such thermoplastics. However,
it is important to note that the mere mixing of anticaking agents with the particular bicyclic
nucleators disclosed herein is sufficient to prevent the problematic cementation issues by
themselves, without the need for air-jet milling. Thus, although air-jet rnilling is considered a
preferred embodiment for this invention, there is no intention to require such a step is
absolutely necessary for full practice and success with this nucleator technology.
A further surprising result accorded the particular nucleator technology disclosed
lerein is that when the anticaking agent is air-jet milled with such a nucleator compound, a
dramatic low-dusting result is accorded. It is generally accepted with the powdered
compounds art (of any kind), not to mention, specifically, within the powdered thermoplastic
nucleator art, that air-jet milling to low particle sizes more likely than not will result in
dusting problems. Such a result is noticeable, as one example, when a storage container is
opened initially; dust materials will float from the container itself, thereby dusting the area,
with the possibility of contaminating machinery, people, clothing, etc. The air-jet milled
bicyclic nucleator/anticaldng agent combination does not exhibit an appreciable level of
dusting, to the contrary. Without intending to be bound to any specific scientific theory, it is
believed that the electrical charge on the anticaking agent basically neutralizes the opposite
charge present on the bicyclic nucleator compounds during storage. As like charges repel,
without such neutralization the bicyclic nucleator compounds will most likely repel one
another causing dusting problems as a result. The anticaking agent thus through charge
neutralization, even in very low amounts, may prevent nucleator repulsion, thereby reducing
the production of dust after storage. In any event, such a result is, again, highly surprising for
small particle size air-jet milled powders.
Air jet-milled compounds are preferred for this invention due to low dusting during
storage, better apparent dispersion within target molten thermoplastics, and thus overall the
ability of such small, substantially uniform particle size nucleator formulations (nucleator
plus anticaking agent, at least) to provide increased peak crystallization temperatures and
decreased haze measurements in target thermoplastic articles, as well as reduced propensities
for cementation and growth during storage.
Preferred Embodiments of the Invention
This invention can be further elucidated through the following examples where
examples of particularly preferred embodiment within the scope of the present invention are
Production of Nucleating Salt
To a solution of disodium bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylate (30.0 g) in
water (70 g) was added 0.5 g palladium on activated carbon (5 wt%). The mixture was
transferred into a Parr reactor and was subjected to hydrogenation (50 psi, room temperature)
for 8 hours. The activated carbon was filtered out, and the resultant solution was spray dried
to give a white powder (m.p >300 °C). Spray drying was accomplished via a spray dryer
using a rotary atomizer having an atomizer speed set at 9600 rpm with the inlet temperature
set at 400°F (~204-205°C), and the outlet temperature kept between 220-225°F (-104-
I08°C). NMR and IR analyses were consistent with that of the expected structure of
disodium bicyclo[2.2.1]heptane-2,3-dicarboxylate (hereinafter referred to as HPN-68,
whether in spray dried or other form).
Initial Particle Size Distribution. Nucleation. Clarification, Compaction, and Growth Tests
The spray dried HPN-68 nucleator powders were initially analyzed for particle size
distribution measurements. Such were taken by employing the following method:
Laser light scattering particle size measurement
For the purposes of the herein described invention, particle size measurements of all
nucleator powders (whether spray dried or air jet-milled, or including an anticaking agent
therein) were conducted using a MICROTRAC® XI00 laser light scattering instrument. The
size was calculated from a diffraction pattern that developed because of laser light interacting
with the particles. The angles at which the light was scattered in combination with the
intensities of the scattered light were measured by a light-sensitive detector system. The
electrical values developed by the detector system were used to calculate the volume of
particles as a function of particle size. The distribution provided the opportunity to calculate
many parameters such as the mean volume diameter or D4,3 value also known as the MVD (a
weighted arithmetic mean for the particle diameter weighted by volume of the sample) and
the 95th perceutile or the D95 value (the maximum size of 95% of all the particles within the
tested sampie)(wherein diameter is the equivalent spherical diameter of all such samples,
knowing that perfect spherical configurations and thus measurements are most likely
unavailable for such measurements). It also allowed calculation of percentiles in order to
divide the distribution into specific percentage amounts. These values were used to specify
product particle size characteristics.
The procedure involved transfer of a representative sample of the nucleator powder
directly to the instrument fluid recirculation system containing a fluid that would not dissolve
the powder, hi this case, an organic chemical, specifically, in this instance, a highly branched
paraffin available from Exxon Corporation under the tradename ISOPAR® G was used to
suspend the water-soluble powder. Food- grade lecithin was added to the ISOPAR® G
paraffin to enhance wetting and maintain final dispersion of the powder particles. Ultrasonic
energy was applied to separate the suspended particles that stuck together (agglomerated).
The instrument was men activated to collect the scattered laser light and calculate the particle
size distribution and various distribution features.
More specifically, powder was transferred to a solution of ISOPAR® G paraffin that
included 0.07% (W/V) liquid soy bean lecithin that was already circulating within the
instrument. The flow rate was optimized to provide sufficient agitation in order to suspend
all particles without causing bubbles in the circulating solution. The nucleator powder was
then added in an amount to achieve sufficient scattered h'ght for measurement without causing
optical effects such as multiple scattering, which can induce errors. A proper amount of
powder will provide an approximate transmission value of 90% or obscuration value of 10%
following ultrasonic treatment [values of transmission in this instance ranged from 0.85 to
0.95 (obscuration 0.05 - 0.15)]. The amount of powder added ranged from approximately 10
mg to 35 nig while the circulating system contained approximately 250 ml of ISOPAR®
G/lecithin solution. The weighing dish used was washed with the circulating fluid solution to
ensure quantitative transfer of the powder from the dish into the circulating solution.
Calculations were performed on the scattered h'ght signals that were measured by a
silicon light sensitive detector system. To correct for light scattering optical effects that occur
as a property of the material in relation to the suspending fluid, Mie scattering calculations or
modifications were used. These calculations include the use of refractive index of the
material and the suspending fluid. The refractive index of ISOPAR® G is documented to be
1.42. The refractive index of the powder materials was found to be 1.54 using the wellaccepted
Beclce line light microscopic method. For the spray dried HPN-68 powders alone
(without anticaking agents), the distributions were recorded as a D95 of 126.3 micrometers
and a MVD of 51.1 micrometers.
Furthermore, thermoplastic compositions (plaques) were produced comprising the
above-produced nucleator salt without any further treatment (e.g., spray drying, air jetmilling)
and sample homopolymer polypropylene (HP) resins. One kilogram batches of
target polypropylene were produced in accordance with the following table:
Component Amount
Polypropylene homopolymer (Basell Profax® 6301) 1000 g
Irganox® 1010, Primary Antioxidant (from Ciba Specialty Additives) SOO.ppm
frgafos® 168, Secondary Antioxidant (from Ciba Specialty Additives) 1000 ppm
Calcium Stearate 800 ppm
Nucleator as noted
The base HP and all additives were weighed and then blended in a low-intensity
mixing procedure using a 6 liter Kemutec Ribbon Blender for 5 minutes at 110 rpm. All
samples were then melt compounded on a Killion single screw extruder at a ramped
temperature from about 200° to 235°C through four heating zones. The melt temperature
upon exit of the extruder die was about 245°C. The screw had a diameter of about 2.5 cm
and a length/diameter ratio of 24:1 and was equipped with a 60 mesh (250 micron) screen.
Plaques of target polypropylene plus nucleator were then molded on an Arburg 25 ton
injection raolder (with a barrel temperature set at 230°C). The plaques had dimensions of
about 50 mm X 75 mm X 1.25 mm, and the mold had a mirror finish. The mold cooling
circulating water was controlled at a temperature of 25°C.
The resultant plaques were tested for peak crystallization temperatures (by Differential
Scanning Calorimetry) and haze (through utilization of a hazemeter). Peak crystallization
temperature is a predictor of the cooling time needed to form a solid article in a molding
process. The higher the peak crystallization temperature, the less cooling time is required to
form the desired solid part. The polymer peak crystallization temperature (Tc), was measured
by using DSC according to ASTM D-794-85. This method involved heating the specific
polypropylene composition from 60°C to 220°C at a rate of 20°C per minute to produce a
molten formulation and held at the peak temperature for 2 minutes (for complete melting
thereof). The temperature was then lowered at a rate of 20°C per minute until it readied the
starting temperature of 60°C. The crystallization temperature was thus measured as the peak
maximum during the crystallization exotherm. Haze indicates the transparency of the subject
article and measures the degree of sufficiently large light scattering crystals present therein
via Hunter Hazemeter.
The results for the nucleator salt {hereinafter referred to as HPN-68) at different
concentrations within the HP sample plaques, were as follows:
Performance ofBicyclic Nudeators in Polypropylene Homopolymer
Sample Nucleator (ppm) Crystallization Temp. (°C) Haze (%)
HPN-68 (Spray Dried)(500) 122.3 51
HPN-68 (Spray Dried)(l000) 123.0 45
HPN-68 (Spray Dried)(1500) 124.0 43
The resultant powder sample was also placed in a glass vial with such that the top
layer was fiat within the vial. This level was indicated with a black marker. The vial was
then exposed to 110°F and 95% humidity in a Tenney Twenty Conditioning Chamber for 7
days (hereinafter the "heated high-humidity test"). The powder was subsequently observed
for volume expansion (growth) and compaction (cementation). A steel spatula was used to
determine if the powder was compact. If it was easy to push the spatula through the powder
to the bottom of the vial, it was labeled as not compact. If a lot offeree needed to be used, it
was labeled as compact. If the volume within the glass vial increased more than 5% over the
initial volume measurement during conditioning over the 7-day period, then growth was
exhibited. The spray dried HPN-68 samples made above exhibited compaction as well as
significant growth (the powder grew so much that it "domed" by forming a meniscus well
above the marked black line), above 10% of the original volume.
Thus, these cementation and growth problems coupled with the high haze and
potentially low peak crystallization temperatures noted previously associated with these spray
dried HPN-68 samples, it was reasoned that reducing the particle sizes may contribute to
better overall properties for this highly effective thermoplastic nucleator.
Initial Inventive Salt Processing
Therefore, another HPN-6S nucleator salt sample was produced, as above, collected,
and either high-intensity mixed or milled on a Rotajet milling instrument, with the belief that
decreasing the particle size of the nucleator compound could potentially improve the
performance of such compounds in thermoplastics as well as possible improve the storage
stability characteristics as well. Such a high-intensity mixing procedure involved treating
(combining) the already-spray dried HPN-68 powders together with the polypropylene
granules and otfier additives within an 8 liter Papenmeier-type mixer for 1 minute at about
1600 rpm. Air jet-milling involved utilization of a fluidized bed opposed jet grinding mill
with a turbine classifier (from Fluid Energy). In such an instrument, the speed of the turbine
and the airvelocity can be used to control the particle size distribution produced therefrom.
The resultant air jet-milled samples were tested for particle size distribution in the following
In terms of cementation and growth, the same problems were present after testing
within glass vials through the high-temperature humidity test as noted above for the air jetmilled
samples. Growth (and the same "doming" problem for the spray dried HPN-68
samples) and cementation were exhibited by these ah" jet-milled samples, thereby indicating
the need for a different approach to remedying such issues.
Furthermore, the particular air jet-milled powders were also tested for peak
crystallization temperatures and haze within HP plaques (as above). In order to determine the
efficacy of such air jet-milled samples in different commercial situations, such samples were
blended with the polymer (here, HP granules) in both low- and high-intensity blending
processes. Such a high-intensity mixing procedure involved blending the HP granules and
nucleator compounds in an 8 liter Papenmeier-type mixer for 1 minute at about 1600 rpm (as
above); low-intensity mixing followed the same procedure with the 6 liter Kemutec ribbon
blender as noted previously.
The results, for both tests, as well as the particle size measurements thereof, are listed
in the following table for the HPN-68 nucleator powders from above (both air jet-milled and
spray dried, high-intensity mixed nucleator powders), with both high-intensity blended with
HP granules prior to melt processing (High-Intensity below indicates the treatment accorded
spray-dried compounds prior to any further mixing; Air Jet-Milled indicates such a step rather
than initial spray-drying). Examples 1-4 were resins including air jet-milled HPN-68
nucleator compounds; Examples 5 and 6 included spray-dried nucleators, but high-intensity
blended with the HP resin,
Particle Sizes of Small Particle Size HPN-68 Nucleators and Performance Thereof in
(Table Removed)

Thus, for both physical particle size reduction steps, haze and peak crystallization
temperature were essentially the same, with better results for the high-intensity mixed spraydried
types. This result is most likely due to the fact that although the air jet-milled particles
are smaller in size, they have a propensity to agglomerate at a relatively high rate as well,
thereby increasing the overall size of the compounds requiring dispersion within the target
resin. Thus, the low-intensity mixing with the resin apparently fails to properly
deagglomerate the nucleator prior to polymer article formation, resulting in much higher haze
results and somewhat lower crystallization temperatures. Furthermore, under the
aforementioned high-temperature humidity test, it was found that similar cementation and
growth results were exhibited between the spray dried types and the smaller air jet-milled
particle samples. Therefore, it was reasoned that a different approach utilizing such small
particle-sized nucleator salts were necessary to provide the best overall commercial viability
of such highly desired thermoplastic nucleating agents.
Inclusion of Anticaldng Agents
It was then theorized that the presence of an anticalcing agent (or dispersant) after salt
production and/or prior to storage may aid in preventing such agglomeration (cementation)
problems. A number of types were tested including silica gel, silica gel treated with 50 wt. %
of eurucamide (C2a fatty amide) (SYLOBLOC® M250), calcium stearate, talc, DHT-4A,
calcium carbonate, magnesium sulfate, sodium sulfate, and calcium sulfate, all as nonlimiting
types for such a purpose. The nucleator/anticaking agent formulations tested were as
follows, with the amounts listed as weight % of the total combination of the formulation
Sample Label HPN-68 Amount fwt%) Anticaking Agent and Amount (vrt.%)
A 70 SYLOBLOC® M250 (30)
B 70 SYLOBLOC® 48 (30)
C 70 Calcium Stearate (30)
I) 70 Talc (30)
E 70 DHT-4A (30)
F 70 SYLOBLOC® M25 0(30)*
G 70 Calcium Carbonate (30)
H 70 Magnesium Sulfate (30)
I 70 Sodium Sulfate (30)
J 70 - Calcium Sulfate (30)
These formulations were blended together through high-intensity mixing (Preblend),
except for *, which was blended, then air jet-milled using the same procedure as noted above
for such milling.
About 20 grams of the blends (powders) of each Sample from the previous Table were
placed in separate glass vials and subjected to the high-temperature humidity test as discussed
above, and evaluated (after the 7-day period) for volume expansion (growth) and
cementation. The results were as follows:
Growth and Cementation Performance of Nudeator/Anticaking Agent Formulations
Sample Growth (Yes or No) Cementation (Yes or No)
HPN-68 (alone) Yes Yes
A No No
B No No
C No No
D No No
E No No
F No No
G Yes Yes
H Yes Yes
I No Yes
J No Yes
Thus, Samples A-F provided the desired results, whereas the others surprisingly failed
at least one of the tests for long-term storage stability and ultimate usefulness for the resin
producer. Thus, Samples A-F proved to be the most effective additives for this purpose as
stacking and agglomeration were not empirically observed.
The Sample A and F blends (of HPN-68 nucleator and SYLOBLOC® M250) from
the Formulation Table, above, were then utilized for further testing, including particle size
distribution, HP haze levels, and HP peak crystallization temperatures (following the same
test protocols as noted above). It was surmised that particle size manipulation could be
attained to the level necessary to effectuate the low haze and high peak crystallization
temperature properties desired, as well as accord the needed low cementation and growth
characteristics for long-term storage via three different procedures involving the inclusion of
an anticalcing agent with the high performing bicyclic nucleator compounds:
a) simultaneously air jet-milling the uucleator and anticalcing agent together,
b) adding the anticaking agent to previously air jet-milled nucleator compounds,
c) high-intensity mixing previously spray-dried nucleator compounds with the
anticaking agent and HP resin. Comparative results were likewise obtained for samples with
both spray-dried and air jet-milled nucleator/anticaking formulations (low intensity-mixed
with the HP granules) as well to determine if particle size was important for such desirable
improvements. Different combinations of HPN-68 and SYLOBLOC® M250 samples (in
terms of ratios of parts) were blended with the target resin formulations prior to melting in
accordance with these di fferent procedures. The ultimate resin formulations were
compounded on a single screw extruder, then molded into plaques (as above) and tested for
the noted haze and peak crystallization temperature characteristics, all as discussed above.
The results were as follows [the letters a, b, and c indicate the same procedures as noted
above; the label "comparative" after such a letter indicates the samples were low intensityrnixed
with the target resin granules], for particle sizes (taken prior to blending with the resin
granules; if high intensity-mixing was followed for blending with the target resin granules,
then no particle size measurements were made), haze, and peak crystallization temperature
measurements. The ratio indicates the number of parts of nucleator to number of parts of
anticaldng agent within such a formulation; thus, 70/30 indicates 70 parts HPN-68 to 30 parts
Particle Sizes of Inventive and Comparative HPN-68 Nudeator/SYLOBLOC®M250
Formulations and Performance Thereof in Polypropylene Homopolymer
(Table Removed)
Surprisingly, the inventive small particle-size samples exhibited drastic increases over
peak crystallization temperatures and noticeable reductions in haze levels when compared to
plaques produced with the nucleator alone, whether physically treated to reduce particle size
or not. Furthermore, it is evident that high-intensity mixing provides improvements over
low-intensity mixing in these characteristics as well and the addition of the anticaldng agent
within the molten thermoplastic during manufacture unexpectedly provided similar results
within the ultimate article. Thus, one embodiment of this invention basically requires the
presence of small particle-size bicyclic nucleator compounds alone or in combination with
co-milled or co-spray dried anticaldng agents, or separately introduced anticaldng agents
within the thermoplastic manufacturing process in order to provide unexpectedly good
improvements in physical and optical properties within ultimately produced thermoplastic
articles, with the co-milled powders and high-intensity resin blending procedures providing
the optimum results (particularly at 80/20 nucleator to anticaking agent ratios). Furthermore,
the inventive co-milled and co-spray dried small particle size powders of the inventive
nucleator/anticaking agent formulations provide unexpectedly improved physical properties
within the stored powders in terms of cementation and growth (although the presence of
anticaking agents alone appear to provide benefits in such an instance and thus small particle
sizes are not always required).
Having described the invention in detail it is obvious that one skilled in the art will be
able to make variations and modifications thereto without departing from the scope of the
present invention. Accordingly, the scope of the present invention should be determined only
by the claims appended hereto.

We Claim:
1. A thermoplastic additive composition comprising at least one anticaking agent component selected from the group consisting of silica gel, talc, dihydrotalcite, metal carboxylic acids, and any mixtures thereof, and at least one nucleating compound conforming to the structure of Formula (I)
(Formula Removed)
wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are individually selected from the group consisting of hydrogen, C1-C9 alkyl, hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine, and
C1-C9 alkylamine, halogen, phenyl, alkylphenyl, and geminal or vicinal carbocyclic having up to nine carbon atoms, R' and R" are the same or different and are individually selected from the group consisting of hydrogen, C1-C30 alkyl, hydroxy, amine, polyamine, polyoxyamine, C1-C30 alkylamine, phenyl, halogen, C1-C30 alkoxy, C1-C30 polyoxyalkyl, C(O)-NRnC(O)O-R'", and C(O)O-R"', wherein R11 is selected from the group consisting of C1-C30 alkyl, hydrogen, C1-C30 alkoxy, and C1-C30 polyoxyalkyl, and wherein R'" is selected from the group consisting of hydrogen, a metal ion, an organic cation, polyoxy-C2-C18-alkylene, C1-C30 alkyl, C1-C30 alkylene, C1-C30 alkyleneoxy, a steroid moiety, phenyl, polyphenyl, C1-C30 alkylhalide, and C1-C30 alkylamine; wherein at least one of R' and R" is either C(O)-NRnC(O)O-R'" or C(O)O-R"', wherein if both R' and R" are C(O)O-R'" then R'" both R' and R" may be combined into a single bivalent metal ion or a single trivalent metal overbase, wherein the anticaking agent and nucleating compound are present in the composition in a weight ratio of anticaking agent to nucleating compound of from about 10:90 to about 30:70.
2. A thermoplastic additive composition as claimed in claim 1 wherein said nucleating
compound conforms to the structure of Formula (II)
(Formula Removed)
wherein M1 and M2 are the same or different and are independently selected from the group consisting of metal or organic cations or the two metal ions are unified into a single metal ion (bivalent, for instance, such as calcium, for example), and R1, R2, R3, R4, R5, R6, R7, R8, R9, and R10 are individually selected from the group consisting of hydrogen C1-C9 alkyl, hydroxy, C1-C9 alkoxy, C1-C9 alkyleneoxy, amine, and C1-C9 alkylamine, halogen, phenyl, alkylphenyl, and geminal or vicinal carbocyclic having up to 9 carbon atoms. Preferably, the metal cations are selected from the group consisting of calcium, strontium, barium, magnesium, aluminum, silver, sodium, lithium, rubidium, potassium, and the like.
3. A thermoplastic additive composition as claimed in claim 1, wherein said metal or organic cation is a metal cation selected from the group consisting of Group I and Group II metal ions.
4. A thermoplastic additive composition as claimed in claim 3, wherein said metal cation is selected from the group consisting of sodium, potassium, calcium, lithium, rubidium, barium, magnesium, and strontium, silver, zinc, aluminum.
5. A thermoplastic additive composition as claimed in claim 4, wherein said metal cation is sodium.
6. A thermoplastic additive composition as claimed in claim 1, wherein said anticaking
agent is a silica gel.
7. A thermoplastic additive composition as defined in claim 1, wherein said composition is present in a form selected from the group consisting of a powder, a pellet, or a liquid, and wherein said composition also comprises at least one thermoplastic polymer.
8. A thermoplastic additive composition as defined in claim 2, wherein said composition is present in a form selected from the group consisting of a powder, a pellet, or a liquid, and wherein said composition also comprises at least one thermoplastic polymer.
9. A thermoplastic additive composition as claimed in claim 1, wherein said composition is present in a form selected from the group consisting of a powder, a pellet, or a liquid, and wherein said composition also comprises at least one thermoplastic polymer.
10. A thermoplastic additive composition as claimed in any of the preceding claims as and when used for preparing a thermoplastic article along with atleast one polyolefin.










1789-DELNP-2006-Correspondence-Others (09-02-2010)--.pdf

1789-DELNP-2006-Correspondence-Others (09-02-2010).pdf





1789-DELNP-2006-Description (Complete)-(09-02-2010).pdf

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1789-DELNP-2006-Petition 137-(09-02-2010).pdf

Patent Number 245193
Indian Patent Application Number 1789/DELNP/2006
PG Journal Number 02/2011
Publication Date 14-Jan-2011
Grant Date 06-Jan-2011
Date of Filing 03-Apr-2006
Name of Patentee MILLIKEN & COMPANY
# Inventor's Name Inventor's Address
PCT International Classification Number C08K 5/098
PCT International Application Number PCT/US2004/025071
PCT International Filing date 2004-08-04
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/679217 2003-10-03 U.S.A.
2 10/679239 2003-10-03 U.S.A.