Title of Invention

RESIN COMPOSITION COMPRISING POLYAMIDE AND POLYESTER BLENDED WITH LITHIUM SULFONATE INTERFACIAL TENSION REDUCING AGENT

Abstract A polymer composition and wall of a container made from such composition is set forth comprising a polyamide and polyester and a sufficient of an interfacial tension reducing agent such that the polyamide domains stretch disproportionately to the amount of stretch experienced by the polyester both with an without a cobalt salt.
Full Text Polvamides and polyesters blended with a lithium salt interfacial tension reducing agent
Priority and cross references
This patent application claims the benefit of the priority of United States Provisional Patent Application Serial No. 60/725,085 filed October 7, 2005 and United States Provisional Patent Application Serial No. 60/827,147 filed September 27, 2006. The teachings of these provisional patent applications are incorporated herein by reference.
Field of invention
This invention relates to the stretched wall of a container for packaging.
Background of the invention
United States Patent Applications 2002/0001684 (Jan 3, 2002), 20030134966 (July 13, 2003) and 20050106343 (May 19, 2005), all of which have a common inventor Kim, teach a composition of PET (A), a polyamide, MXD6 nylon (B), with cobalt octoate. The Kim series of applications teach that when the PET/MXD6/Cobalt octoate composition is injected molded into a preform (parison) and then oriented (stretched) into a blown bottle, the resultant bottle is hazy. The Kim applications also identify the cause of the haze. According to Kim, the haze is caused by the MXD6 domains dispersed into the PET which upon orientation have been stretched to the point where the size of the domains are greater than the wavelength of light.
Kim et al teaches that smaller domains reduce the haze caused by the previously large domains. One of ordinary skill knows there are two ways to have smaller domains in the stretched bottle. One is to reduce the size of the starting domains in the preform or parison, the other is to not orient or stretch the bottle as much. The solution selected in the Kim series of applications to replace the injection blow process of making the preform/parison and subsequently orienting(stretching) the preform into a blown bottle with a much lower stretch process called extrusion blow.
The Kim applications also teach that a container made with PET/MXD6/Cobalt octoate exhibits higher oxygen barrier (lower permeation rate) presumably due to the well known

ability of the cobalt octoate to catalyze the reaction of MXD6 nylon with oxygen. While Kim et al, therefore teaches that reducing the size of the MXD6 domains as a way to reduce the haze in stretched containers, it does not teach how to solve the haze in an injection blown container or how to reduce the size of the domains in an injection blown container, presumably because this was already known in the art prior to the invention of Kim.
JP-2663578-B2 (October 15, 1997) to Yamamoto et al identifies the same problem as the Kim applications with the same composition. Yamamoto et al discloses that a hazy stretch blown bottle is created when a composition of polyester (A) and MXD6 nylon (B) is injection molded into a parison (preform) and oriented (stretched) into a bottle. Recall that Kim et al teach that this haze is cause by large domains and the only difference being that the bottle of Kim et al contains cobalt octoate.
Yamamoto et al, then teaches that the haze in the PET/MXD6 injection blown bottle may be eliminated by incorporating a third polyester component (C) wherein the third polyester component has 5-sodium sulfoisophthalate derived from 5-sodium sulfoisophthalic acid in its polymer chain. The copolymerization of the 5-sodium. sulfoisophthalic acid is taught in Table 3 of Yamamoto with the conclusion being: when polyester copolymerized with 5-sodium sulfoisophthalate is used as the component (C), the transparency is improved and the haze is notably reduced. One of ordinary skill would therefore solve the haze of Kim's injection molded/stretch blown bottle containing PET/MXD6/cobalt octoate by adding the polyester (C) copolymerized with 5-sodium sulfoisophthalate taught by Yamamoto et al. One would not eliminate the cobalt octoate found in the Kim applications because that would reduce the oxygen barrier of the container.
United States Patent No. 5,300572 (April 5, 1994) to Tajima et al teaches how to reduce the domain size of a polyamide dispersed into a polyester. Tajima et al reduces the domain size of the polyamide by adding sodium sulfoisophthalic acid, either copolymerized into the backbone of polyester (A) or as a third component (C) which is a polyester copolymerized with the sodium sulfoisophthalic acid. Since the Kim applications teaches that reducing the size of the polyamide domains solves the haze one of ordinary skill

acid, resorcinol dicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof, and where D is a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof, and an interfacial tension reducing agent wherein the polyamide is dispersed into the polyester and the interfacial tension between the polyester and the polyamide is such that the average diameter of the particles of the polyamide dispersed in the polyester is less than 150nm and the particle size measurement is conducted on the layer at the region selected from the group consisting of an unstretched portion of the layer and a portion of the layer prior to stretching.
The invention further discloses that the interfacial reducing agent is selected from the group consisting of functionalized and non-functionalized lithium sulfonates, hydroxyl terminated polyethers, cyclic amides and polyethers, with lithium sulfoisophthalate being a particularly useful lithium interfacial tension reducing agent.
An effective amount of lithium sulfonate, in particular, lithium sulfoisophthalate (derived from 5-sulfoisophthalic acid monolithium salt), is about 0.05 to 0.1 mole percent, with an optimal amount being with the range of about 0.1 to about 2.0 mole percent, with the range of about 0.1 to about 1.1 mole percent being more optimal, and about 0.18 to about 0.74 being even better yet, with the range of about 0.18 to about 0.6 mole percent being the most optimal range.
The invention further discloses that MXD6 and PA 6 are particularly suited polyamides and that the composition or wall of the container can be free of cobalt compounds.
Description of the figures
Figure 1 depicts a scanning electron microscope photomicrograph (SEM) of polyamide domains dispersed in a polyester matrix in the absence of the interfacial tension reducing agent, such as lithium sulfoisophthalate derived from lithium sulfoisophthalic acid (LiSIPA). As detailed in the test method section, the sample was prepared by removing the polyamide with cold formic acid and exposing the sample to a scanning electron microscope.

While not to be bound by any theory it is hypothesized that the lithium salt does not nucleate the crystallization of the polyester like the other metals (e.g. sodium) and thus the domains shrink while the stretched article is cooling. The reduced interfacial tension between the polyamide and polyester coupled with the stretch characteristics increases the dispersion of the polyamide in the polyester and the average domain size of the dispersed polymer in an unstretched portion of an article comprising the composition is less than 125nm, with better results at less than l00nm, even better results with the average domain size being less than 75nm, and with domains less than 60nm being the most optimal average domain size in the unstretched portion of the container wall.
The stretch phenomenon can be characterised by the percent stretch which is defined as the stretch ratio of the polyamide domains divided by the stretch ratio of the matrix (polyester) in the same direction. Theoretically this should be 100%, in that the domains stretch the same amount as the polyester. However, when the lithium salt is used, the percent stretch is often less than 75%, with many observations less than 50%, and in one instance less than 30%. It is believed that the lower the percent stretch, the better.
This invention also provides for a blend of a crystallizable polyethylene terephthalate or its copolymers, a polyamide (in particular MXD6 or nylon-6) and a separate interfacial tension reducing agent to form the stretched wall of a container. The separate interfacial tension reducing agent could be a metal salt of sulfonated polystyrene or a metal salt of sulfonated polyester.
This invention provides for a modified polyester, in particular a crystallizable polyethylene terephthalate or its copolymers, blended with a polyamide, in particular MXD6 or nylon-6; or a polyester, in particular polyemylene terephthalate or its copolymers, blended with a modified polyamide, in particular MXD6 to form the stretched wall of a container.
Any polyester or polyamide suitable for making the desired container is suitable for the current invention provided the composition comprising the polyester and polyamide has a sufficient amount of interfacial tension reducing agent either as a third component or incorporated into the polyester chain, the polyamide chain. A combination of the separate

These acids or esters may be reacted with an aliphatic diol preferably having from about 2 to about 24 carbon atoms, a cycloaliphatic diol having from about 7 to about 24 carbon atoms, an aromatic diol having from about 6 to about 24 carbon atoms, or a glycol ether having from 4 to 24 carbon atoms. Suitable diols include, but are not limited to, ethylene glycol, 1,4-butanediol, trimethylene glycol, 1,6-hexanediol, 1,4-cyclohexanedimethanol, diethylene glycol, resorcinol, 1,3-propanediol and hydroquinone.
A useful polyester is a crystallizable polyester with more than 85% of its acid units being derived from terephthalic acid. It is generally accepted that polyesters with greater than 15% comonomer modification are difficult to crystallize. However, this invention includes polyesters which would crystallize and have more than 15% comonomer content.
Polyfunctional comonomers can also be used, typically in amounts of from about 0.01 to about 3 mole percent. Suitable comonomers include, but are not limited to, trimellitic anhydride, trimethylolpropane, pyromellitic dianhydride (PMDA), and pentaerythritol. Polyester-forming polyacids or polyols can also be used. Blends of polyesters and copolyesters may also be useful in the present invention.
One suitable crystallizable polyester is polyethylene terephthalate (PET) or a copolymer modified with lithium sulfoisophthalate formed from the di-ester or di-carboxylic acid of lithium sulfoisophthalate in the approximately 1:1 stoichiometric reaction of acids, or their di-esters, with ethylene glycol. Copolymers are also suitable. Specific copolymers and terpolymers of interest are crystallizable polyesters comprising lithium sulfoisophthalate in combinations of isophthalic acid or its diester, 2,6 naphthalate dicarboxylic acid or its diester, and/or cyclohexane dimethanol. The optimal levels of lithium sulfoisophthalate are within the range of 0.1 and 2.0 mole percent based upon-the acid moieties in the polymer. While greater than 2.0 mole percent is not deleterious to the intended effect, greater than 2.0 mole percent achieves little or no additional improvement.
The amount of lithium sulfonate, in particular, lithium sulfoisophthalate (derived from 5-sulfoisophthalic acid monolithium salt), is about 0.05 to 10.0 mole percent, with an optimal amount being with the range of about 0.1 to about 2.0 mole percent, with the range of

The polyesters of this invention may also contain small amounts of phosphorous compounds, such as phosphates, and a catalyst such as a cobalt compound, that tends to impart a blue hue. Also, small amounts of other polymers such as polyolefins can be tolerated in the continuous matrix. While WO 2005/023530 Al teaches the use of cobalt salts as essential to prevent colour formation, the use of cobalt salts is not necessary to reduce the colour formation when the interfacial tension reducing agent is the lithium salt, in particular lithium sulfoisophthalate derived from Lithium SulfoIsoPhthalic Acid (LiSIPA). The molecular structure of lithium sulfoisophthalic acid is:

Lithium sulfoisophthalic acid (LiSIPA) or sulfonic acid lithium salt modified isophthalic acid.
As is evident from the above diagram, the lithium sulfoisophthalic acid comprises is a lithium sulfonate and comprises lithium sulfoisophthalate. The lithium sulfoisophthalate refers to the compound as it is appears incorporated into the polymer chain. This is also known as the repeating unit of lithium sulfoisophthalic acid. Lithium sulfoisophthalate therefore is the lithium sulfoisophthalic acid less one water molecule, with one hydroxyl group removed from one of the carboxyl end groups and a hydrogen removed from the other carboxyl end group. This molecule is then attached to one or more monomers (Ri and R2) in the polymer backbone.

The sulfonate, in this case lithium sulfoisophthalate, is the molecule between the two R groups. Again, R could be the same monomer, in the case of PET, the R's are likely the same being the ethylene glycol moiety as reacted into the polymer chain.

In one embodiment of the invention, the crystallizable polyester of the present invention may comprise recycled polyester or materials derived from recycled polyester, such as polyester monomers, catalysts, and oligomers.
The term crystallizable means that the polyethylene terephthalate can be become semi-crystalline, either through orientation or heat induced crystallinity. It is well known that no plastic is completely crystalline and that the crystalline forms are more accurately described as semi-crystalline. The term semi-crystalline is well known in the prior art and is meant to describe a polymer that exhibits X-ray patterns that have sharp features of crystalline regions and diffuse features characteristic of amorphous regions. It is also well known in the art that semi-crystalline should be distinguished from the pure crystalline and amorphous states.
The polyamides which could be modified or unmodified that are suitable for this invention can be described as comprising the repeating unit amino caproic acid or A-D, wherein A is the residue of a dicarboxylic acid comprising adipic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, resorcinol dicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof, and D is a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof.
These polyamides can range in number average molecular weight from 2000 to 60,000 as measured by end-group titration. These polyamides can also be described as the reaction product of amino caproic acid with itself and/or the reaction product of a residue of dicarboxylic acid comprising adipic acid, isophthalic acid, terephthalic acid, 1,4-cyclohexanedicarboxylic acid, resorcinol dicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof with a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof.
Those skilled in the art will recognize many of the combinations as well known commercially available polyamides. The reaction product of the residue of sebacic acid

each particle has the same equilibrium properties of the other particle. For the purposes of this invention, the term dispersed phase or dispersed polymer refers to the totality of discrete particles of the discontinuous component present in the continuous phase.
It is believed that the polyamide is dispersed into the polyester matrix forming discrete particles in the polyester. And, while not to be bound by any theory, it is also believed that the inferior dispersion of polyester/polyamide system is due to the high interfacial tension (IFT) existing between the two polymers.
For a closed system (see An Introduction to the Principles of Surface Chemistry, Aveyard, R. and Haydon, D.A. 1973), the differential expression for the internal energy U of the system has been described as
dU = dQ + dW where dQ is the heat taken up by the system and dW is the change in work. The relation is then isolated for dW which reduces the equation to
dW = -pdV + ydA where dV is the change in volume and y is the interfacial tension, and dA is the change in interfacial area (the area of the interface between the two components). In the liquid-liquid system, such as exists with the mixture of melted polyester/polyamide, there is no volume change (dV=0), and the equation reduces to the change in work as a function of the interfacial tension and the change in interfacial area.
dW = ydA
The lower the interfacial tension, therefore, the higher the area of contact between the two materials. A higher area of interfacial contact for a given amount of material is only achieved by creating smaller particles of the dispersed material into the matrix material. A higher interfacial contact area requires a smaller diameter, and consequently a greater number of particles. The effectiveness of the interfacial tension reducing agent can be directly established by the average particle size. The lower the average dispersed particle size, the lower the interfacial tension and the more effective the interfacial tension reducing agent.

at least one end group which allows the interfacial tension reducing agent to react with at least one of the other polymers or polymer co-monomers in the composition.
In the case of polyesters, these can be the polar co-monomers used to create PET ionomers. In the case of polyamides, the interfacial tension reducing agent can be the polar co-monomers used to create polyamide ionomers. Examples of these co-monomers are the monovalent and/or divalent salt of the respective sulfonate described in United States Patent No. 6,500,895 (Bl) the teachings of which are incorporated herein. Also included are the monovalent and bivalent metal salts described in the following formulas found in Japanese Patent Application 0 3281246 A, the teachings of which are incorporated herein.
In general, the interfacial tension reducing agent exists in functionalized form of the form X-R, where X* is an alcohol, carboxylic acid or epoxy, most preferably a dicarboxylic acid or diol and R is R is -SO3Li, -COOLi, -OLi, -PO3(Li)2, and X-R is copolymerized into the polyester polymer to modify the interfacial tension. The amount of X-R needed will exceed 0.01 mole percent with respect to the total number of respective dicarboxylic acid or diol moles in the polymer. It is possible for X-R to include both a diol or dicarboxylic acid. In that case, the mole percent is based upon the total number of moles of respective diols, dicarboxylic acids, or polymer repeating units.
The functionalized interfacial tension reducing agent may contain 2 or more R groups. R may also be combined directly to the aromatic ring of X, which could be a diol, a dicarboxylic acid, or a side chain such as a methylene group.


As used in this specification, the term interfacial tension reducing agent refers to the agent as it is exists without being incorporated into the backbone of a polymer and as it has been incorporated into the backbone of the polymer.
Of the metal salts, it has been found that lithium, a monovalent metal, performs much better than sodium. In fact, the lithium salt imparts very little, if any, haze in the polyester matrix when blended with MXD6 and produces a dispersion with average domains lower than levels previously measured. Unlike other systems presented in the art, the lithium salt exhibits a very little increase in haze with increased levels of MXD6, and in fact at some levels no increase in haze was measured. Also, lithium shows dramatically lower yellow colour when melt blended with the polyamide thus eliminating the need for cobalt salt or zinc as described in WO 2005/023530 Al, the teachings of which are incorporated herein. In fact, as described below, the lithium sulfoisophthalate without a cobalt compound has better colour than the sodium isophthalate blended with the same amount of MXD6 in the presence of a cobalt salt.
Of the salt forms, the di-carboxylic acid, di-ester, or pre-reacted low molecular weight oligomers arid other building blocks such as the bis-hydroxyethyl ester of lithium sulfoisophthalate are preferred. It is also possible that the interfacial tension reducing agent, in this case the lithium sulfonate, occur in the diol form as well. Possible alternatives are isethionic acid. It has even been proposed to place the sulfonate at the end of the polyester molecule. This could be accomplished by reacting or copolymerizing the polyester with the sulfonated salt of benzoic acid or other monofunctional species either in die melt reactor or in an extruder. In tins instance the interfacial tension reducing agent reacted with the backbone of the polymer would be lithium sulfobenzoate. One way to describe the various lithium salts is to use the term functionalized lithium sulfonate to describe a compound of the form R-SO3Li, where R is an aliphatic, aromatic, or cyclic compound with at least one functional group that allows the functionalized lithium salt to react with the polyester or polyamide, or their respective monomers or oligomers. Functionalized lithium sulfonates included in this invention are the lithium salts of sulfonated comonomers, including aliphatic and aromatic alcohols, carboxylic acids, diols, dicarboxylic acids, and multifunctional alcohols, carboxylic acids, amines and diamines.

to add another comonomer such as isophthalic acid. For example, a 2 mole percent isophthalate polymer would contain 93 moles terephthalic acid, 2 moles of isophthalic acid, 5 moles of functionalized lithium sulfonate and 100 moles ethylene glycol to make 100 moles of polymer repeat unit.
In the three component blend system, the moles of acid are the moles of acid in the modified polymer plus the moles of acid in the unmodified polymer.
It is also well known that di-ethylene glycol is formed in-situ in the manufacture of polyester and about 2-3 percent of the total moles of glycol will be diethylene glycol. Therefore, the composition is 97 mole percent ethylene glycol and 3 mole percent di-ethylene glycol.
The amount of interfacial tension reducing agent is determined empirically. Generally, a small amount is needed and approaches a critical amount beyond which additional amounts have no "effect. In the surface science field, this amount is referred to as the Critical Micelle Concentration (CMC). As seen in the examples, a small amount of sulfonated material has a significant effect, but at a certain point, around 0.4 or 0.5 mole percent in the case of lithium sulfoisophthalic acid, no increase in effectiveness is seen. Levels above the CMC would be the functional equivalent of the CMC as it pertains to reducing the interfacial tension of the polyester-polyamide. Unlike other salts, the lithium salt, in particular shows an optimum level at approximately between 0.3 and 1.0 moles per 100 moles polymer repeat unit. This can also be expressed as 0.4 to 1.0 mole percent of the acid or glycol moiety to which the lithium salt is attached.
Examples of modified polyesters employed in the present invention are those prepared by virtually any polycondensation polymerization procedure. The traditional techniques can be divided into the ester, acid, and modified processes. In the ester process, the dimethyl ester of the carboxylic acid or acids is reacted with the glycol or glycols in the presence of heat and the methanol removed yielding the bis-hydroxyethyl ester of the acids. The bis-hydroxyethyl ester is then polymerized in its liquid form by subjecting the material to vacuum and heat to remove the glycols and increase the molecular weight. A typical

sulfohydroxy benzene, the lithium salt of hydroxy benzene sulfonic acid, or oligomers or polymers containing the lithium sulfoisophthalate.
The phrases "and derivatives" and "and its derivatives" refer to the various functionalized forms of the interfacial reducing agent which can be copolymerized into the polymer. For example, lithium sulfoisophthalate "and its derivatives" refers collectively and is not limited to lithium sulfoisophthalic acid, the dimethyl ester of lithium sulfoisophthalic acid, the bis-hydroxyethyl ester of lithium sulfoisophthalic acid, the di-alcohol of lithium sulfoisophthalate, low molecular weight oligomers, and high I.V. polymers containing lithium sulfoisophthalate in the polymer chain.
The same nomenclature applies to the glycol or alcohol.
In the acid process, the starting materials are the di-carboxylic acids, with water being the primary by-product. The charge ratio in a typical acid process is 98 moles terephthalic acid, 2 moles of a metal salt of sulfoisophthalic acid (e.g. lithium sulfoisophthalic acid -LiSEPA), and 120 moles of glycols, typical ethylene glycol. After reaction of the glycols with the acids, the material is subjected to the same polymerization process conditions as the ester process.
The modified processes are variations of either process: combining the intermediary product at certain steps. One example is to pre-polymerize the raw materials without the interfacial tension reducing agent to a low molecular weight. In the case of the examples described below, the molecular weight of the low molecular weight polyester was typically in the range 0.096 to 0.103 dl/g having a carboxyl end group number ranging from 586 to 1740 equivalents per 1,000,000 grams of polymer. Obviously, the molecular weight could be easily varied without undue experimentation as it has been for many years by those of ordinary skill in the art when optimizing the addition point for their additives.
Another example of a variation of is to use the acid process with just terephthalic acid to produce its low molecular weight intermediate and the ester process used to produce the bis-hydroxyethyl ester of the homopolymer sulfonated polyester. These two intermediates

invention in the article. In fact, the lowest average dispersed particle size of 57nm was obtained using a compartmentalized pellet structure.
Other methods of incorporating similar co-monomers are listed in United States Patent Numbers 3,936,389, 3,899,470, 5,178,950, and United States Statutory Invention Registration HI 760, the teachings of all of which are incorporated herein.
The polyester and polyamide are melt blended and then injection molded, pelletized or formed into a film. Analysis of the dispersion at this point shows the polyamide dispersed into the polyester matrix phase. There are many techniques to analyse the dispersion properties.
The domain size of the dispersed polymer is measured in the unstretched area. The unstretched area can exist in an unstretched area of the wall, such as the thread, neck, and sealing portions or it can be measured on the article before stretching. Measuring the size of the dispersed particles in the article before stretching the article yields the same value as measuring the size in the unstretched portion after stretching. Therefore, if the stretched wall does not have an unstretched portion, the size of the dispersed particles prior to stretching can be used. In many instances, the measurement was made on the preform or parison prior to stretching.
In one example, a fractured sample is treated with cold formic acid to remove the polyamide from the PET and the sample subjected to scanning electron microscopy (SEM). Based upon contrast, the domains where the polyamide once was can be readily determined and measured. (See Figures 1 and 3).
Since the molded sample is unstretched, the particles are present as spheres. The SEM picture can be analyzed either manually or with various computer programs. The average particle size can then be easily calculated from the picture. The average can be determined by summing the diameters of all the particles in the picture and dividing by the number of particles in the picture. Alternatively, a statistically significant sample size could be used instead of all the domains in the populations.

enough to interfere with the visible light. Mathematically expressed, one of the diameters of the ellipse will be greater than approximately 400nm but less than approximately 720nm; corresponding to the wavelength range of visible light.
Stretching occurs when the molded article, film or fiber is subjected to a force and pulled or elongated. Generally, the article is heated to a temperature below the melting point of the matrix polymer and then pulled in one or two, or in the case of a bubble, three directions. A fiber or a type of film is an example of uni-axial stretching. A fiber is pulled in the direction of its length to build strength. A film will be placed in a machine which has a sequence of gears that move progressively faster, thus stretching the film between each gear or other attaching mechanism.
In the case of bottles, biaxially oriented films, or blown films, the article is pulled in at least two directions. In the case of a blown bottle or reheat blow or reheat stretch blow bottle, pressure such as compressed air is introduced into the article, also known as a preform or parison. The air will then expand the article to take on the shape of the blow mold surrounding the article. Depending upon the design of the article and the mold, the article will have varying degrees of stretch in the two directions.
In films, there are some techniques which simultaneously stretch the article in the machine and transverse directions. However, in industrial practice it is more common to stretch the film first one way, then the other.
It is this stretched article where the object of this invention has utility. By lowering the interfacial tension so that the particles of the dispersed polymer are extremely small, the article can be stretched to higher levels, and still maintain a reduced haze appearance because many of the stretched particles are still below 400nm (the wavelength of light).
The amount of stretch, also known as draw, is described as the stretch ratio. In the case of a uniaxial stretch, the ratio is the length of the stretched article divided by the length of the unstretched article, where both lengths are measured in the direction of stretch. A 2 inch specimen stretched to 8 inches would have a stretch ratio of 4.

3, or 133nm. For the article stretched 2 x 4.5, the particle size should be less than or equal to 400 divided by 4.5, or 89 nm. The target average diameter of the dispersed particles in the unstretched matrix phase could then be easily expressed as 400 divided by longest dimension of stretch. For example, if the final stretch dimension was 7x2, then the goal would be to modify the interfacial tension so that the average particle diameter in the unstretched article would be 400 divided by 7, or 57nm. It is not only important that the average diameter be below a certain size, but that the distribution be narrow enough to reduce the number of dispersed particles which will exist between 400-700nm after stretching. While reducing the average domain size is important to minimize the number of domains in the visible region, narrowing the wide distribution is also important.
Because the particles occur in a distribution, the average particle diameter is used. Given the ranges of stretch ratios, the average diameter of the dispersed particles in the unstretched container should be less than 125 nm, more preferably less than 100 nm, even more preferably less than 80nm. For articles to be stretched into high stretch, high strength materials, average particle diameters of less than 90nm should be used, with particle size less than 70nm preferred, and particle size less then 60nm even more preferred, with the best appearance occurring with an average particle diameter less than 50nm.
What has been discovered is that when the lithium salt is used, the domains do not follow the expected behaviour. Examination of series 9 demonstrates this. The percent stretch which is defined earlier as the stretch ratio of the polyamide domains divided by the stretch ratio of the polyester matrix in the same direction can be determined as follows.
The domain stretch ratio, or stretch ratio of the domain, is the average length of the domains after stretching in the measured direction of stretch divided by the average length of the domains prior to stretching. Since the unstretched domain is spherical, any radius or direction can be used.
The stretch ratio of the polyester or matrix is the change in amount the polyester has been stretched coincident with the approximate area where the' domain is measured. The easiest way to measure the stretch ratio of the polyester for the percent stretch calculation is to

Although an intermediate product, the preform is capable of containing a packaged content as it is closed on one end and open on the other.
A water activated oxygen scavenger may also be compounded into the composition. These oxygen scavenging compositions are well known in the literature and usually comprise oxidizable metal particles, particularly elemental iron or aluminum, and an activating component such as a water soluble salt, electrolytic, acidic, non-electrolytic/acidic or water hydrolysable Lewis acids. The activating component can either be blended or deposited upon the oxidizable metal particles. The polymer composition may also contain polyamide, in particular, poly-m-xylylene adipamide (MXD6). If one wants to just increase the passive barrier, the polyamide may be blended without the oxygen scavenging composition.
The oxygen-scavenging compositions can be added directly to the polyester or polyamide, whether modified or not, at any step where one of the polymer streams is in its liquid state such as melt polymerization, pelletizing, separate compounding or melt-fabrication operation, such as the extrusion section thereof, after which the molten mixture can be advanced directly to the article-fabrication line.
Typical values of the oxidizable metal will be from 300 to 3000 ppm by weight of the polymers in the composition.
The colour and brightness of a thermoplastic article can be observed visually, and can also be quantitatively determined by a HunterLab ColorQuest Spectrometer. This instrument uses the 1976 CIE, a*, b* and L* designation of colour and brightness. An a* coordinate defines a colour axis wherein plus values are toward the red end of the colour spectrum and minus values are toward the green end.
The b* coordinate defines a second colour axis, wherein plus values are toward the yellow end of the visible spectra and minus values are toward the blue end of the visible spectra.
Higher L* values indicate enhanced brightness of the material.

accomplished by placing 5 melt batches of the same molecular constituency into the vessel. The vessel pressure was reduced to 0.13 millibar, the temperature set at 225 °C, and the vessel slowly rotated so the material tumbled on itself. After 12 hours of tumbling, the temperature was increased to 230 °C for 6 hours, and then increased to 235 °C for 2 hours. The pellets were then cooled and discharged. The final Intrinsic Viscosity was 0.82 dl/gm. The following batches were made according to the process of Example I and used in the experiments.
Table I - Properties of Melt Produced Material

Note: 19 gms of sodium acetate were added to the melt reactions yielding the higher melt point. The sodium acetate suppresses the formation of di-ethylene glycol as reflected in the increased melt point.
* Although the abbreviation is to the Acid, it refers to the acid moiety, for instance, NaSIPA refers to the sodium sulfoisophthalic acid moiety which occurs as sodium sulfoisophthlate in the polymer chain.
EXAMPLE 2 Manufacture of Modified Polymer via Extrusion.
25 mole percent sodium sulfoisophthalate and 75 mole percent terephthalate modified polymer was made using the melt production techniques of Example 1. The polymer was then dried and melt blended with a twin screw extruder into Cleartuf® 8006S Polyester Resin from M&G Polymers, LLC, USA to achieve a polymer with 2 mole percent SIP A. Cleartuf® 8006S Polyester Resin is a 98.5 mole percent terephthalic acid, 1.5 mole percent isophthalic copolymer of polyethylene terephthalate resin. The polymer was then solid phase polymerized under vacuum to 0.862 dl/gm IV.



for the resulting mole percentages. The amount of lithium sulfoisophthalate reported in the tables is based upon measuring the amount of sulfur in the polymer and not upon the amount charged.
This material was combined with 7% by weight MXD6 nylon (Grade 6007 from Mitsubishi Gas Chemical, Japan) and injection molded into a preform. The preform was subjected to SEM analysis (Figure 3) and compared to a similar preform with unmodified polyester (Figure 1). As can be readily seen from the photomicrographs, the average polyamide particle size of the unmodified system is much larger than the particle size of the modified system. The larger particle size of the unmodified system indicates the higher interfacial surface tension. The analysis of the domains (Figures 2 and 4) show a much broader distribution for the unmodified system as well. The superiority of the lithium sulfoisophthalate is also demonstrated in Table III which compares the change in Haze per mil. The 2 mole percent lithium sulfoisophthalate showed almost no change in haze due to increasing nylon contents, while the 2 mole percent sodium sulfoisophthalate still shows a significant affect.
It is noteworthy that the sodium sulfoisophthalate is not preferred for the stretched application, despite what the prior art claims. The prior art states that sodium sulfoisophthalate is the preferred material for the three component system. What has been discovered is that the sodium sulfoisophthalate gave an unacceptable haze, regardless of whether the stretched sample contained nylon. Unlike sodium sulfoisophthalate in these examples, lithium sulfoisophthalate did not exhibit a relatively high inherent haze, thus making it the best commercially acceptable material.
The optimum concentration and superiority of the low level of lithium sulfoisophthalate is demonstrated in Tables III and IV. In all cases, 7% MXD6 Grade 6007 from Mistubishi Gas Chemical Co, Japan, was melt blended with PET - lithium sulfoisophthalate and made into parisons or preforms and subsequently blown into bottles. The mean particle diameter in nanometers was measured using the cold formic acid technique followed by SEM analysis as described in the test method section.

EXAMPLE 4 Comparative Examples
Tables IV and V demonstrate the ability of the polyester polymer modified with a small amount of the co-monomer to virtually eliminate the haze brought on by blending nylon into the polymer. 3 and 5 weight percent of two polyamides (MXD6 - Grades 6001 and 6007 from Mitsubishi Gas Chemical, Japan) were melt blended into preforms with Clearruf® Polyester Resin 8006S and Turbo®® II (both available from M&G Polymers USA) and the three modified materials listed in Table I. While 8006S and Turbo® II were the controls, Turbo® II is modified with approximately 5 mole percent isophthalic acid. 0.5L Bottles were blown from the preforms and haze measured on each bottle (as opposed to the sidewall). The haze is reported Table IV and the change in haze per mil of the stretched wall from the control with no polyamide are reported in Table V. The change is haze per mil from the control is calculated by subtracting the haze per mil of the wall without the nylon from the haze per mil of the wall with the nylon. The more effective the material in reducing the interfacial tension, the less the change in haze as more nylon is added. In each case, the modified polymers suppressed the haze caused by the addition of the nylon.
The particle dispersion analysis was also conducted on the various unstretched preforms. The results for the dispersion of 5% nylon (MXD6 Grade 6001) are shown when added to the unmodified materials, the reactive extrusion method and the melt polymerization method. The results in Table IV indicate that the reactive extrusion achieves some advantages, but that complete randomization has not occurred. The superiority of the random copolymer is demonstrated by the fact that in each and every case, the diameter of the particle is significantly smaller than the particle of the others.




* The nomenclature NaSIPA or LiSIPA in this table means the mole percent of the acid moietites of lithium sulfoisophthalate. However, one skilled in the art knows that mole percent of lithium sulfoisophthalate is equal to the mole percent of the starting monomer.
The bottle Hunter b* is measured on a 0.5Liter bottle with nominal wall thicknesses of 0.36mm to 0.42mm, where the bottle itself is placed into a properly adapted machine and the light passes through both bottle sidewalls. Thus a bottle having a Hunter b* colour as measured on the bottle through both sidewalls of less than 20 units without Cobalt is easily achievable through the teachings of this specifications. Also taught is a bottle with a Hunter b* colour of less than 15 units. Also present in the bottle may be a colorant or colorant system such as a pigment or dye which reduces the Hunter b*. It is also noted that these bottles had less than 0.5% haze per mil
EXAMPLE 6 Lithium Sulfonate with Aliphatic Polyamide (nylon 6)


Example Series 9 - Demonstration of Lithium's Unique Stretch Characteristics
The following examples demonstrate the functionality of this invention. In examples 1 through 3, 100 grams of polyamide pellets with the end group and molecular weights provided in Table I were dried separately and melt blended with 1900 grams of polyester having the characteristics demonstrated in Table VI. Note that the polyester in Examples 9B and 9C contained the interfacial tension reducing agent with sodium and lithium respectively at the mole percents indicated polymerized into the backbone of the polymer. Example 9B is Crystal 3919/089 available from E.I. Dupont Nemours. The polyester with interfacial reducing agent, lithium sulfoisophthalate, copolymerized into the backbone used in Example 9C were prepared as disclosed earlier.

0.05 relative to the solvent at the same temperature using a Ubbelohde IB viscometer. The intrinsic viscosity is calculated using the Billmeyer equation based upon the relative viscosity.
The intrinsic viscosity of high molecular weight or highly crystalline poly(ethylene terephthalate) and related polymers which are not soluble in phenol/tetrachloroethane was determined by dissolving 0.1 gms of polymer or ground pellet into 25 ml of 50/50 trifluoroacetic Acid/Dichloromethane and determining the viscosity of the solution at 30°C +/- 0.05 relative to the solvent at the same temperature using a Type OC Ubbelohde viscometer. The intrinsic viscosity is calculated using the Billmeyer equation and converted using a linear regression to obtain results which are consistent with those obtained using 60/40 phenol/tetrachloroethane solvent. The linear regression is IV in 60/40 phenol/tetrachloroethane = 0.8229 x IV in 50/50 trifluoroacetic Acid/Dichloromethane + 0.0124
The Hunter Haze measurement
The measurements were taken through the bottle side-walls. A HunterLab ColorQUEST Sphere Spectrophotometer System, assorted specimen holders, and green, gray and white calibration tiles, and light trap was used. The HunterLab Spectrocolorimeter integrating sphere sensor is a colour and appearance measurement instrument. Light from the lamp is diffused by the integrating sphere and passed either through (transmitted) or reflected (reflectance) off an object to a lens. The lens collects the light and directs it to a diffraction grating that disperses it into its component wave lengths. The dispersed light is reflected onto a silicon diode array. Signals from the diodes pass through an amplifier to a converter and are manipulated to produce the data. Haze data is provided by the software. It is the calculated ratio of the diffuse light transmittance to the total light transmittance multiplied by 100 to yield a "Haze %" (0% being a transparent material, and 100% being an opaque material). Samples prepared for either transmittance or reflectance must be clean and free of any surface scratches or abrasion. The size of the sample must be consistent with the geometry of the sphere opening and in the case of transmittance; the sample size is limited by the compartment dimension. Each sample is tested in four different places, for example on the bottle sidewall or representative film area.

domains is then carried out to determine the mean, the median and the distribution of the domains as in Figure 4, and frequency of domains at a given size interval per unit area for each sample.


CLAIMS What is claimed is:
1. A container wall comprising a layer with a stretched region, wherein the layer is comprised of a polyamide comprising at least one reaction product selected from the group consisting of the reaction of amino caproic acid with itself, or the reaction product of A-D where A is a residue of dicarboxylic acid comprising adipic acid, isophthalic acid, terephthalic acid, 1,4 cyclohexanedicarboxylic acid* resorcinol dicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof, and where D is a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof, dispersed into a crystallizable polyester with at least 85% of the polyester acid units derived from terephthalic acid or the dimethyl ester of terephthalic acid, and an interfacial tension reducing agent selected from the group consisting of functionalized and non-functionalized lithium sulfonates, wherein the layer is free of cobalt compounds.
2. The wall of claim 1, wherein the interfacial tension reducing agent is lithium sulfoisophthalate.
3. The wall of claim 2 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.
4. The wall of claim 1 wherein the polyamide is MXD6 nylon.
5. The wall of claim 4 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.
6. The wall of claim 4 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the polyester.

7. The wall of claim 1 wherein the average diameter of the dispersed particles is less-than l00nm.
8. The wall of claim 7 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester. .
9. The wall of claim 7 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the polyester.
10. The wall of claim 1 wherein the average diameter of the dispersed particles is less than 75nm.
11. The wall of claim 10 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.
12. The wall of claim 10 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the polyester.
13. The wall of claim 1 wherein the average diameter of the dispersed particles is less than 60nm.
14. The wall of claim 13 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.
15. The wall of claim 13 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the polyester.

16. The wall of claim 1 wherein average diameter of the dispersed particles is less man 50nm.
17. The wall of claim 16 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.
18. The wall of claim .16 wherein the interfacial tension reducing agent is lithium sulfoisophthalate present at a level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the polyester.
19. A resin composition comprising a polyamide comprised of at least one reaction product selected from the group consisting of the reaction of amino caproic acid with itself, or the reaction product of A-D where A is a residue of dicarboxylic acid comprising adipic acid, isophthalic acid, terephthalic acid, 1,4 cyclohexanedicarboxylic acid, resorcinol dicarboxylic acid, or naphthalenedicarboxylic acid, or a mixture thereof, and where D is a residue of a diamine comprising m-xylylene diamine, p-xylylene diamine, hexamethylene diamine, ethylene diamine, or 1,4 cyclohexanedimethylamine, or a mixture thereof, dispersed into a crystallizable polyester with at least 85% of the polyester acid units derived from terephthalic acid or the dimethyl ester of terephthalic acid, and an interfacial tension reducing agent selected from the group consisting of functionalized and non-functionalized lithium sulfonates, wherein the composition is void of a cobalt compound.
20. The composition of claim 19 wherein the lithium sulfonate is selected from the group consisting of lithium sulfoisophthalate and lithium sulfobenzoic acid.
21. The composition of claim 20, wherein the lithium sulfoisophthalate is present at at least 0.1 mole percent based upon the moles of acid units in the polyester.
22. The composition of claim 20 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.

23. The composition of claim 20 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and \.\ mole percent based upon the moles of acid units in the polyester.
24. The composition of claim 20 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and 0.7 mole percent based upon the moles of acid units in the polyester.
25. The composition of claim 20 wherein the lithium sulfoisophthalate is present at a level within the range of 0.18 and 0.6 mole percent based upon the moles of acid units in the polyester.
26. The composition of claim 20 wherein the polyamide is partially aromatic.
27. The composition of claim 26, wherein the lithium sulfoisophthalate is present at a level of least 0.1 mole percent based upon the moles of acid units in the polyester.
28. The composition of claim 26 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the polyester.
29. The composition of claim 26 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the polyester.
30. The composition of claim 26 wherein the lithium sulfoisophthalate is present at a level within the range of 0.1 and 0.7 mole percent based upon the moles of acid units in the polyester.

31:. The composition of claim 26 wherein the lithium sulfoisophthalate is present at a
level within the range of 0.18 and 0.6 mole percent based upon the moles of acid units in
the polyester. .
32. The composition of claim 26, wherein the partially aromatic polyamide is MXD6
nylon.
33. The composition of claim 32, wherein the lithium sulfoisophthalate is present at
least 0.1 mole percent based upon the moles of acid units in the polyester.
34. . The composition of claim 32 wherein the lithium sulfoisophthalate is present at a
level within the range of 0.1 and 2.0 mole percent based upon the moles of acid units in the
polyester.
35. The composition of claim 32 wherein the lithium sulfoisophthalate is present at a
level within the range of 0.1 and 1.1 mole percent based upon the moles of acid units in the
polyester.
36. The composition of claim 32 wherein the lithium sulfoisophthalate is present at a
level within the range of 0.1 and 0.7 mole percent based upon the moles of acid units in the
polyester.
37. The composition of claim 32 wherein the lithium sulfoisophthalate is present at a
level with in the range by 0.18 and 0.6 mole percent based upon the moles of acid units in
the polyester.
3 8. The layer of the wall of a container comprising the composition of any of claims 19 to37.


Documents:

2259-CHENP-2008 AMENDED PAGES OF SPECIFICATION 29-10-2013.pdf

2259-CHENP-2008 AMENDED PAGES OF SPECIFICATION 25-07-2013.pdf

2259-CHENP-2008 AMENDED CLAIMS 29-10-2013.pdf

2259-CHENP-2008 AMENDED CLAIMS 25-07-2013.pdf

2259-CHENP-2008 CORRESPONDENCE OTHERS 29-10-2013.pdf

2259-CHENP-2008 EXAMINATION REPORT REPLY RECEIVED 25-07-2013.pdf

2259-CHENP-2008 EXAMINATION REPORT REPLY RECEIVED 26-10-2012.pdf

2259-CHENP-2008 FIRST PAGE OF PCT 26-10-2012.pdf

2259-CHENP-2008 FORM-1 29-10-2013.pdf

2259-CHENP-2008 FORM-3 25-07-2013.pdf

2259-CHENP-2008 FORM-3 29-10-2013.pdf

2259-CHENP-2008 OTHERS 29-10-2013.pdf

2259-CHENP-2008 AMENDED CLAIMS 01-05-2013.pdf

2259-CHENP-2008 AMENDED PAGES OF SPECIFICATION 01-05-2013.pdf

2259-CHENP-2008 FORM-3 01-05-2013.pdf

2259-CHENP-2008 OTHER PATENT DOCUMENT 01-05-2013.pdf

2259-chenp-2008 abstract.pdf

2259-chenp-2008 claim.pdf

2259-chenp-2008 correspondences-others.pdf

2259-chenp-2008 description (complete).pdf

2259-chenp-2008 drawings.pdf

2259-CHENP-2008 EXAMINATION REPORT REPLY RECEIVED 01-05-2013.pdf

2259-chenp-2008 form-1.pdf

2259-chenp-2008 form-18.pdf

2259-chenp-2008 form-26.pdf

2259-chenp-2008 form-3.pdf

2259-chenp-2008 form-5.pdf

2259-chenp-2008 pct.pdf


Patent Number 258022
Indian Patent Application Number 2259/CHENP/2008
PG Journal Number 48/2013
Publication Date 29-Nov-2013
Grant Date 27-Nov-2013
Date of Filing 06-May-2008
Name of Patentee M & G POLIMERI ITALIA S.P.A
Applicant Address VIA MOROLENSE KM 10 I-03010 PATRICA
Inventors:
# Inventor's Name Inventor's Address
1 HEATER, PAUL, LEWIS 8801 BLOUGH AVENUE SOUTHWEST NAVARRE OHIO 44662
2 ELLIOTT, GULIZ, ARF 7250 HONEYDALE DRIVE NORTHFIELD CENTER, OHIO 44067
PCT International Classification Number C08K5/42
PCT International Application Number PCT/EP2006/009705
PCT International Filing date 2006-10-06
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/827,147 2006-09-27 U.S.A.
2 60/725,085 2005-10-07 U.S.A.