WO2013169325A1

WO2013169325A1 - Additive compositions and thermoplastic polymer composition comprising the same

Info

Publication number: WO2013169325A1
Application number: PCT/US2013/027212
Authority: WO
Inventors: Jiang Li
Original assignee: Milliken & Company
Priority date: 2012-05-11
Filing date: 2013-02-22
Publication date: 2013-11-14

Abstract

An additive composition comprises an acid compound and a salt of a fatty acid. The additive composition can conform to the structure of Formula (III). In the structure of Formula (III), R₁ and R₂ are independently selected from the group consisting of hydrogen and C₁-C₁₈ alkyl groups, and R₃ is an alkanediyl group. A method for producing a thermoplastic polymer composition comprises the steps of providing a thermoplastic polymer, providing an additive composition according to the invention, and mixing the thermoplastic polymer and the additive composition to produce a thermoplastic polymer composition.

Description

ADDITIVE COMPOSITION AND THERMOPLASTIC

POLYMER COMPOSITION COMPRISING THE SAME

TECHNICAL FIELD OF THE INVENTION

[0001] The invention provides an additive composition that is suitable for use in the production of thermoplastic polymer compositions and a thermoplastic polymer composition comprising such an additive composition. In particular, the additive composition is believed to be suitable for use as a nucleating agent (i.e., crystalline nucleating agent) for thermoplastic polymers, such as polypropylene polymers.

BACKGROUND

[0002] Plastics have found a wide variety of uses in modern industry. The relative ease with which they can be processed and molded into a variety of shapes and their physical properties have contributed to their ubiquity. Despite these attributes, plastics and articles made from plastics still have room for improvement. For example, due to their plastic nature, articles made from plastics oftentimes do not exhibit desirable flexural properties, such as stiffness. In other words, plastic articles can exhibit relatively high degrees of bending when stresses are applied to the article. While such bending may be desirable in certain applications, it is not desirable in others. The stiffness of a plastic article can be increased by increasing its thickness or molding structural members into the article, but such modifications can render the article unsuitable due to its increased size and/or weight.

Furthermore, despite the relatively low density of plastics in comparison to, for example, metals, manufacturers continue to seek means that they can use to reduce the weight of a plastic article without significantly reducing its physical properties.

[0003] A need therefore remains for additive compositions that can be used to improve the physical properties of plastics and other polymer-based materials, such as their flexural properties. The embodiments of the invention described in this application seek to address this continued need. BRIEF SUMMARY OF THE INVENTION

[0004] In a first embodiment, the invention provides an additive composition comprising an acid compound and a salt of a fatty acid. The acid compound can conform to the structure of Formula (III) below

In the structure of Formula (III), Ri and R₂ are independently selected from the group consisting of hydrogen and C-i-C-is alkyl groups, and R₃ is an alkanediyl group.

[0005] In a second embodiment, the invention provides a method for making a thermoplastic polymer composition. The method comprises the steps of (a) providing a thermoplastic polymer, (b) providing an additive composition, and (c) mixing the thermoplastic polymer and the additive composition to produce a thermoplastic polymer composition. The additive composition comprises an acid compound and a salt of a fatty acid. The acid compound can conform to the structure of Formula (III) below

DETAILED DESCRIPTION OF THE INVENTION

[0006] As noted above, in a first embodiment, the invention provides an additive composition comprising an acid compound and a salt of a fatty acid. The acid compound preferably is an acid compound conforming to the structure of Formula (I) below

(I)

In the structure of Formula (I), Ri and R₂ can be attached at any suitable position on the aryl rings and are independently selected from the group consisting of hydrogen, alkyl groups (preferably C-i-C-is alkyl groups), and cycloalkyl groups (preferably C₃- C-I2 cycloalkyl groups). In a preferred embodiment, Ri and R₂ are independently selected from the group consisting of alkyl groups, more preferably C-1 -C9 alkyl groups. In a more preferred embodiment, Ri and R₂ are each terf-butyl groups. R₃ is selected from the group consisting of a carbon-carbon bond (i.e., a bond between the carbon atoms of the two aryl rings), a divalent sulfur atom, and alkanediyl groups. In a preferred embodiment, R₃ is an alkanediyl group. Suitable alkanediyl groups include, but are not limited to, alkanediyl groups conforming to the structure of Formula (II)

In the structure of Formula (II), R₄ and R₅ are independently selected from the group consisting of hydrogen, alkyl groups (preferably C-|-C-|₈ alkyl groups), and cycloalkyl groups (preferably C3-C-12 cycloalkyl groups), including cycloalkanediyl groups in which R₄ and R₅ form part of the cycloalkanediyl group.

[0007] In a preferred embodiment, the acid compound conforms to the structure of Formula (III) below

In the structure of Formula (III), Ri and R₂ are independently selected from the group consisting of hydrogen and alkyl groups (preferably C-i-ds alkyl groups). In a preferred embodiment, Ri and R₂ are independently selected from the group consisting of alkyl groups, more preferably C-i-Cg alkyl groups. In a more preferred embodiment, Ri and R₂ are each terf-butyl groups. R₃ is an alkanediyi group, including those alkanediyi groups described above in connection with the structure of Formula (I). In a preferred embodiment, R₃ is an alkanediyi group conforming to the structure of Formula (IV)

In the structure of Formula (IV), R₄ is selected from the group consisting of hydrogen and alkyl groups (preferably C C₄ alkyl groups). In a preferred embodiment, R₃ is an alkanediyi group conforming to the structure of Formula (IV) and R₄ is hydrogen.

[0008] As noted above, the composition provided by the invention comprises a salt of a fatty acid. The salt of the fatty acid can comprise any suitable cation. In a preferred embodiment, the salt of the fatty acid comprises an alkali metal cation. In a more preferred embodiment, the salt of the fatty acid comprises a cation of an alkali metal selected from the group consisting of sodium and lithium.

[0009] The salt of the fatty acid can be derived from any suitable fatty acid. The fatty acid can be either a saturated fatty acid (i.e., a fatty acid containing no carbon-carbon double bonds in its aliphatic chain) or an unsaturated fatty acid (i.e., a fatty acid containing one or more carbon-carbon double bonds in its aliphatic chain). Suitable fatty acids include, but are not limited to, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, myristoleic acid, palmitoleic acid, sapienic acid, oleic acid, elaidic acid, vaccenic acid, linoleic acid, lenoelaidic acid, a-linolenic acid, arachidonic acid, eicosapentaenoic acid, erucic acid, and docosahexaenoic acid. In a preferred embodiment, the salt of the fatty acid comprises a saturated fatty acid. Suitable saturated fatty acids include, but are not limited to, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, and cerotic acid. The fatty acid can comprise an aliphatic chain of any suitable length. In a preferred embodiment, the fatty acid comprises six or more carbon atoms, more preferably ten or more carbon atoms. Thus, in a preferred

embodiment, the fatty acid is selected from the group consisting of capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and mixtures thereof. More preferably, the fatty acid is selected from the group consisting of lauric acid, stearic acid, and mixtures thereof. Most preferably, the fatty acid is stearic acid.

[0010] As noted above, the salt of the fatty acid can comprise any suitable cation in combination with any suitable fatty acid. In a preferred embodiment, the salt of the fatty acid comprises an alkali metal cation and a fatty acid selected from the group consisting of capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and mixtures thereof. In a more preferred embodiment, the salt of the fatty acid comprises a cation of an alkali metal selected from the group consisting of sodium and lithium and a fatty acid selected from the group consisting of capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, cerotic acid, and mixtures thereof. In a more preferred embodiment, the salt of the fatty acid is selected from the group consisting of sodium stearate, lithium stearate, sodium laurate, lithium laurate, and mixtures thereof.

[0011] The acid compound and the salt of the fatty acid can be present in the composition of the invention in any suitable amounts. For example, the acid compound and the salty of the fatty acid can be present in the composition in a molar ratio of about 0.1 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.2 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.3 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.4 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.5 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.6 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.7 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.8 mol or more of the salt of the fatty acid to 1 mol of the acid compound, about 0.9 mol or more of the salt of the fatty acid to 1 mol of the acid compound, or about 1 mol or more of the salt of the fatty acid to 1 mol of the acid compound. In a preferred embodiment, the acid compound and the salt of the fatty acid are present in the composition in a molar ratio of about 0.5 mol or more of the salt of the fatty acid to 1 mol of the acid compound. In a more preferred

embodiment, the acid compound and the salt of the fatty acid are present in the composition in a molar ratio of about 1 mol or more of the salt of the fatty acid to 1 mol of the acid compound.

[0012] The composition of the invention can comprise other suitable

components in addition to the acid compound and the salt of the fatty acid. For example, the composition can comprise nucleating agents, clarifying agents, reinforcing agents, fillers, and other additives suitable for use in the production of thermoplastic polymer compositions and/or polymers. Nucleating agents suitable for use in the composition of the invention include, but are not limited to,

c/s-1 ,2-cyclohexanedicarboxylate salts (e.g., calcium

c/s-1 ,2-cyclohexanedicarboxylate, disodium c/s-1 ,2-cyclohexanedicarboxylate, aluminum c/s-1 ,2-cyclohexanedicarboxylate hydroxide, dilithium

c/s-1 ,2-cyclohexanedicarboxylate, and strontium c/s-1 ,2-cyclohexanedicarboxylate) bicyclo[2.2.1 ]heptane-2,3-dicarboxylate salts (e.g., disodium bicyclo[2.2.1 ]heptane- 2,3-dicarboxylate and calcium bicyclo[2.2.1 ]heptane-2,3-dicarboxylate), and mixtures thereof. Clarifying agents suitable for use in the composition of the invention include, but are not limited to, trisamides, bisphenol phosphates, and acetal compounds. Suitable trisamide clarifying agents include, but are not limited to, amide derivatives of benzene-1 ,3,5-tricarboxylic acid, derivatives of /V-(3,5-bis-formylamino-phenyl)- formamide (e.g., /V-[3,5-bis-(2,2-dimethyl-propionylamino)-phenyl]-2,2-dimethyl- propionamide), derivatives of 2-carbamoyl-malonamide (e.g., /V,/V-bis-(2-methyl- cyclohexyl)-2-(2-methyl-cyclohexylcarbamoyl)-malonamide), and mixtures thereof. Suitable bisphenol phosphate clarifying agents include, but are not limited to, aluminum 2,2'-methylenebis-(4,6-di-terf-butylphenyl) phosphate, lithium 2,2'- methylenebis(4,6-di-terf-butylphenyl) phosphate, and mixtures thereof.

[0013] Acetal clarifying agents suitable for use in the composition of the invention include the acetal compounds produced by the condensation reaction of a polyhydric alcohol and an aromatic aldehyde. Polyhydric alcohols suitable for producing such acetal clarifying agents include, but are not limited to, acyclic polyols, such as xylitol, sorbitol, 1 ,2,3-trideoxynonitol, and 1 ,2,3-trideoxynon-1 -enitol.

Aromatic aldehydes suitable for producing such acetal clarifying agents include, but are not limited to, aromatic aldehydes containing a single aldehyde group with the remaining positions on the aromatic ring being either unsubstituted or substituted. Thus, suitable aromatic aldehydes include benzaldehyde and substituted

benzaldehydes (e.g., 4-methylbenzaldehyde, 3,4-dimethylbenzaldehyde, and

4-propylbenzaldehyde). The acetal compound produced by the above-described reaction can be a mono-acetal, di-acetal, or tri-acetal compound (i.e., a compound containing one, two, or three acetal groups, respectively), with the di-acetal compounds being preferred. Suitable acetal clarifying agents include, but are not limited to, dibenzylidene sorbitol, di(para-methylbenzylidene) sorbitol,

1 ,3:2,4-bis(3',4'-dimethylbenzylidene) sorbitol, 1 ,2,3-trideoxy-4,6:5,7-bis-0-[(4- propylphenyl)methylene]-nonitol, and combinations thereof.

[0014] Reinforcing agents and fillers suitable for use in the additive

composition include, but are not limited to magnesium oxysulfate whiskers, glass fibers, talc, mica, and mixtures thereof. Suitable magnesium oxysulfate whiskers include, but are not limited to, those comprising a magnesium oxysulfate compound selected from the group consisting of 5Mg(OH)₂ · MgS0₄ · 3H₂0; 5Mg(OH)₂ · MgS0₄ · 2H₂0; 3Mg(OH)₂ · MgS0₄ · 8H₂0; Mg(OH)₂ · MgS0₄ · 5H₂0; Mg(OH)₂ · 2MgS0₄ · 3H₂0; 4.34Mg(OH)₂ · MgS0₄ · 2H₂0; and Mg(OH)₂ · 2MgS0₄ · 2H₂0.

[0015] The additive composition of the invention is believed to be suitable for use in the production of thermoplastic polymer compositions. In particular, it is believed that the additive composition of the invention is suitable for use in the nucleation (i.e., crystalline nucleation) of semicrystalline thermoplastic polymers, such as a polypropylene polymer (e.g., an isotactic polypropylene polymer). While not wishing to be bound to any particular theory, it is believed that the components of the additive composition will, when present in a molten thermoplastic polymer, react with each other to produce a salt of the acid compound. And it is believed that this salt of the acid compound functions as a nucleating agent (i.e., crystalline nucleating agent) for the thermoplastic polymer. Furthermore, it is believed that this salt of the acid compound is a particularly effective nucleating agent due to the relatively small size of the particles (i.e., particles of the salt of the acid compound) produced by this in situ reaction. These relatively small particles stand in contrast to the much larger particles that result from forming the salt of the acid compound prior to addition to the thermoplastic polymer, which has been the conventional method for forming such salts used as nucleating agents.

[0016] While not wishing to be bound to any particular theory, it is believed that the additive composition of the invention can be particularly effective at improving the flexural properties (e.g., flexural modulus). For example, it is believed that the additive composition of the invention can yield increases of five percent (5%) or more in the flexural modulus of a polymer as compared to the same polymer that has been nucleated with a "conventional" nucleating agent of the same composition (i.e., a nucleating agent containing the same salt of the acid compound where the salt has been produced by a reaction performed prior to introducing the nucleating agent into the polymer). Indeed, it is believed that increases in the flexural modulus of as much as eight percent (8%) or more can be achieved through the use of the additive composition of the invention. Applicant believes that these increases in the flexural modulus are commercially significant and unexpected in view of the fact that the actual nucleating agents are believed to be chemically identical in each instance. Furthermore, Applicant believes that these increases are also unexpected because they can be realized even though the total amount of the nucleating agent used is less than that in the "conventional" nucleating agent (this is due to the fact that the additive composition of the invention contains a mixture of the acid compound and a salt of a fatty acid while the "conventional" nucleating agent is composed entirely of a salt of the acid compound).

[0017] Thus, in another embodiment, the invention provides a method for making a thermoplastic polymer composition. In the most general terms, the method entails the addition of an additive composition according to the invention to a thermoplastic polymer, such as a polypropylene polymer (e.g., an isotactic

polypropylene polymer). More specifically, this method comprises the steps of (a) providing a thermoplastic polymer, (b) providing an additive composition, and (c) mixing the thermoplastic polymer and the additive composition to produce a thermoplastic polymer composition. In a preferred embodiment, the method further comprises the step of heating the thermoplastic polymer composition to a

temperature sufficient to at least partially melt the thermoplastic polymer and, optionally, allowing the thermoplastic polymer composition to at least partially cool and solidify. In such embodiments, the thermoplastic polymer composition can be heated to any suitable temperature sufficient to at least partially melt the

thermoplastic polymer. For example, when the thermoplastic polymer is a

polypropylene, the thermoplastic polymer composition preferably is heated to a temperature of about 175 °C or more, about 180 °C or more, about 185 °C or more, about 190 °C or more, about 195 °C or more, or about 200 °C or more. When the thermoplastic polymer is a polypropylene, the thermoplastic polymer composition preferably is heated to a temperature of about 260 °C or less, about 250 °C or less, about 240 °C or less, or about 230 °C or less. Thus, in a preferred embodiment when the thermoplastic polymer is a polypropylene, the thermoplastic polymer composition is heated to a temperature of about 190 °C to about 260 °C, about 190 °C to about 240 °C, or about 200 °C to about 230 °C.

[0018] The thermoplastic polymer used in the method can be any suitable thermoplastic polymer. In a preferred embodiment, the thermoplastic polymer is a polypropylene polymer. In a preferred embodiment, the thermoplastic polymer is a polypropylene homopolymer (e.g., an isotactic polypropylene homopolymer).

[0019] The additive composition used in the method can be any embodiment of the additive composition described above. Thus, the additive composition can comprise an acid compound conforming to the structure of Formula (I) or Formula (III) and a salt of a fatty acid. The acid compound can be any of the acid compounds described above in connection with the additive composition embodiment of the invention. The salt of the fatty acid can be any of the fatty acid salts described above in connection with the additive composition embodiment of the invention.

[0020] In the practice of the method, the additive composition can be mixed with the thermoplastic polymer in any suitable amount. In a preferred embodiment, the additive composition is mixed with the thermoplastic polymer in an amount of about 100 parts or more, about 200 parts or more, about 300 parts or more, about 400 parts or more, about 500 parts or more, about 600 parts or more, about 700 parts or more, about 800 parts or more, about 900 parts or more, or about 1 ,000 parts or more per one million parts of the thermoplastic polymer. More preferably, the additive composition is mixed with the thermoplastic polymer in an amount of about 500 parts or more (e.g., about 1 ,000 parts or more) per one million parts of the thermoplastic polymer. In a preferred embodiment, the additive composition is mixed with the thermoplastic polymer in an amount of about 20,000 parts or less, about 15,000 parts or less, or about 10,000 parts or less per one million parts of the thermoplastic polymer. Thus, in a preferred embodiment, the additive composition is mixed with the thermoplastic polymer in an amount of about 500 parts to about 20,000 parts (e.g., about 1 ,000 parts to about 20,000 parts), about 500 parts to about 15,000 parts (e.g., about 1 ,000 parts to about 15,000 parts), or about 500 parts to about 10,000 parts (e.g., about 1 ,000 parts to about 10,000 parts) per one million parts of the thermoplastic polymer.

[0021] The method of the invention can be carried out or performed in any suitable environment. For example, the method can be performed by simple physical mixing or blending of the thermoplastic polymer (in any suitable form, such as a powder, pellet, or as a molten polymer) and the additive composition (in a powdered or pelletized form). The method can also be performed by physical mixing or blending of the thermoplastic polymer and the additive composition followed by heating the resulting mixture to a temperature sufficient to at least partially melt the thermoplastic polymer. Thus, the method of the invention can, for example, be carried out by adding the additive composition to a thermoplastic polymer and then melt extruding the mixture to produce a pelletized thermoplastic polymer

composition. The method of the invention can also be carried out by adding the additive composition to a thermoplastic polymer and then molding the thermoplastic polymer composition into an article by any suitable molding process (e.g., injection molding).

[0022] The following examples further illustrate the subject matter described above but, of course, should not be construed as in any way limiting the scope thereof. EXAMPLE

[0023] The following example demonstrates the production of additive compositions according to the invention, thermoplastic polymer compositions according to the invention, and the flexural properties of such thermoplastic polymer compositions.

[0024] Six additive compositions (AC 1 -6) were produced by physical blending of an acid compound conforming to the structure of Formula (III) with a salt of a fatty acid. In particular, the acid compound was 2,2'-methylenebis-(4,6-di-terf- butylphenyl)phosphoric acid ("MBDTBPPA"), which has molecular formula of C₂9H₄₃0₄P and a molecular weight of approximately 486.6 g/mol. The fatty acid salt was sodium stearate (NaSt), lithium stearate (LiSt), calcium stearate (CaSt), or zinc stearate (ZnSt).

Table 1 . Composition of additive compositions AC 1 -6.

[0025] Fifteen thermoplastic polymer compositions (TPC 1 -15) were produced by mixing one of the above-described additive compositions (AC 1 -6) with a polypropylene homopolymer (Pro-fax 6301 from LyondellBasell, which has a density of 0.900 g/cm³ and a melt flow rate of 12.0 g/10 min). Three comparative

thermoplastic polymer compositions (CTPC 1 -3) were produced by mixing either sodium 2,2'-methylenebis-(4,6-di-tert-butylphenyl)phosphate ("NA-1 1 ") or

MBDTBPPA with the same polypropylene homopolymer. The polypropylene homopolymer and all additives were weighed as noted in Table 2 below and then blended in a Henschel mixer for 1 minute at approximately 1600 rpm. All samples were then melt compounded on a Deltaplast single screw extruder at a ramped temperature from approximately 204 °C to approximately 232 °C through four heating zones. The melt temperature upon exit of the extruder die was about 246 °C. The molten polymer was filtered through a 60 mesh (250 micron) screen. Flex bars of the thermoplastic polymer composition were then injection molded using an Arburg 25 ton injection molding apparatus. The molder was set at a temperature between approximately 190 °C and 260 °C. The mold cooling water was controlled at a temperature of approximately 25 °C. Flex bars made from each thermoplastic polymer composition were then tested in accordance with ASTM D790 to determine the flexural properties exhibited by each polymer composition.

Table 2. Formulation for TPC 1 -15, CTPC 1 -3, and Control.

Component Amount

Polypropylene homopolymer 1000 g

Irganox® 1010, Primary Antioxidant (BASF) 0.5 g (500 ppm)

Irgafos® 168, Secondary Antioxidant (BASF) 1 g (1 ,000 ppm)

DHT-4A, acid scavenger (Kyowa Chemical Ind. Co., Ltd.) 0.4 g (400 ppm)

Additive Composition as noted in Table 3

Table 3. Formulation and flexural modulus for Control, CTPC 1 -3, and TPC 1 -15.

[0026] As can be seen from the data set forth in Table 3, all of the additive compositions according to the invention produce an increase in the flexural modulus relative to the base polypropylene homopolymer ("Control"). Indeed, even the most modest increase in flexural modulus of approximately 13% relative to the control, which was exhibited by Additive Composition 6, is believed to be commercially significant. The other additive compositions produced increases that are far greater than the control. It is believed that this data demonstrates that the additive composition according to the invention is at least a viable alternative to the

"conventional" nucleating agent, which is sold by Amfine Chemical Corporation under the name "NA-1 1 ."

[0027] Furthermore, the data set forth in Table 3 also demonstrate that several embodiments of the additive composition of the invention exhibit vastly superior performance to the "conventional" nucleating agent. For example, the data for TPC 2 and CTPC 1 show that one additive composition according to the invention (AC 1 ) produces a 6.7% increase in flexural modulus over the "conventional" nucleating agent. The data for TPC 6 and CTPC 1 show that another additive composition according to the invention (AC 2) produces an 8% increase in flexural modulus over the "conventional" nucleating agent. Also, a comparison of the data for TPC 1 , TPC 5, and CTPC 1 shows that the additive compositions AC 1 and AC 2 can produce 5.8% and 8.9% increases, respectively, in flexural modulus over the "conventional" nucleating agent. The observed increases in flexural modulus for TPC 1 and TPC 5 are believed to be especially significant given that an appreciable percentage of the additive composition used in TPC 1 and TPC 5 was the salt of the fatty acid, which is not believed to actively participate in the nucleation of the polymer. In particular, AC 1 , which was used in making TPC 1 , contained

approximately 38% percent sodium stearate, and AC 2, which was used in making TPC 5, contained approximately 50% sodium stearate.

[0028] The data set forth in Table 3 also demonstrates that the observed nucleation effects are not solely attributable to the presence of the acid compound in the additive composition. For example, each of TPC 1 -14, which contains an additive composition according to the invention, exhibits a demonstrably higher flexural modulus than CTPC 2, which was made using the acid compound alone. The increase in flexural modulus relative to CTPC 2 is even more pronounced for TPC 1 -13. Furthermore, a comparison of the flexural modulus data for TPC 1 , TPC 5, TPC 9, and CTPC 2 demonstrate that the observed increases are not merely attributable to higher loadings of the acid compound. Each of TPC 1 , TPC 5, and TPC 9 exhibited a marked increase in flexural modulus over CTPC 2 even though the additive composition used to make each polymer composition contained less acid compound than was used in making CTPC 2. Approximately 38-55% of AC 1 , AC 2, and AC 3 was the salt of the fatty acid. And, as noted above, the salt of the fatty acid is not believed to actively participate in the nucleation of the polymer.

[0029] It is believed that the foregoing data demonstrate the utility of the additive composition according to the invention and the benefits that can be realized from its use in producing thermoplastic polymer compositions. In particular, it is believed that the increase in flexural modulus that can be realized through the use of an additive composition according to the invention are commercially significant and can be leveraged to produce thermoplastic polymer compositions that are suitable for use in a variety of applications where increased stiffness is desired.

[0030] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

[0031] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the subject matter of this application (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open- ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the subject matter of the application and does not pose a limitation on the scope of the subject matter unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the subject matter described herein.

[0032] Preferred embodiments of the subject matter of this application are described herein, including the best mode known to the inventors for carrying out the claimed subject matter. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the subject matter described herein to be practiced otherwise than as specifically described herein. Accordingly, this disclosure includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above- described elements in all possible variations thereof is encompassed by the present disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

Claims

WHAT IS CLAIMED IS:

A composition comprising:

an acid compound conforming to the structure of Formula (III)

(III)

wherein Ri and R₂ are independently selected from the group consisting of hydrogen and C-i-C-is alkyl groups, and R₃ is an alkanediyl group; and

(b) a salt of a fatty acid;

wherein the acid compound and the salt of the fatty acid are present in the composition in a molar ratio of about 0.5 mol or more of the salt of the fatty acid to 1 mol of the acid compound.

2. The composition of claim 1 , wherein R and R₂ are independently selected from the group consisting of CrC₉ alkyl groups.

3. The composition of claim 2, wherein Ri and R₂ are each terf-butyl groups.

4. The composition of claim 1 , wherein R₃ is an alkanediyl group conforming to the structure of Formula (IV) (IV)

wherein R₄ is selected from the group consisting of hydrogen and C C₄ alkyl groups.

5. The composition of claim 4, wherein R₄ is hydrogen.

6. The composition of claim 1 , wherein the salt of the fatty acid comprises an alkali metal cation.

7. The composition of claim 6, wherein the alkali metal cation is a cation of an alkali metal selected from the group consisting of sodium and lithium.

8. The composition of claim 1 , wherein the fatty acid comprises ten or more carbon atoms.

9. The composition of claim 1 , wherein the fatty acid is a saturated fatty acid.

10. The composition of claim 1 , wherein the salt of the fatty acid is selected from the group consisting of sodium stearate, lithium stearate, sodium laurate, lithium laurate, and mixtures thereof.

1 1 . The composition of claim 1 , wherein the acid compound and the salt of the fatty acid are present in the composition in a molar ratio of about 1 mol or more of the salt of the fatty acid to 1 mol of the acid compound.

12. A method for making a thermoplastic polymer composition, the method comprising: providing a thermoplastic polymer;

providing an additive composition comprising

(i) an acid compound conforming to the structure of Formula (III)

(Ill)

wherein R and R₂ are independently selected from the group consisting of hydrogen and C-i-ds alkyl groups, and R₃ is an alkanediyl group; and

(ii) a salt of a fatty acid;

wherein the acid compound and the salt of the fatty acid are present in the additive composition in a molar ratio of about 0.5 mol or more of the salt of the fatty acid to 1 mol of the acid compound; and

(c) mixing the thermoplastic polymer and the additive composition to produce a thermoplastic polymer composition.

13. The method of claim 12, wherein R and R₂ are independently selected from the group consisting of C-|-C₉ alkyl groups.

14. The method of claim 13, wherein R and R₂ are each terf-butyl groups.

15. The method of claim 12, wherein R₃ is an alkanediyl group conforming to the structure of Formula (IV) (IV)

16. The method of claim 15, wherein R₄ is hydrogen.

17. The method of claim 12, wherein the salt of the fatty acid comprises an alkali metal cation.

18. The method of claim 17, wherein the alkali metal cation is a cation of an alkali metal selected from the group consisting of sodium and lithium.

19. The method of claim 12, wherein the fatty acid comprises ten or more carbon atoms.

20. The method of claim 12, wherein the fatty acid is a saturated fatty acid.

21 . The method of claim 12, wherein the salt of the fatty acid is selected from the group consisting of sodium stearate, lithium stearate, sodium laurate, lithium laurate, and mixtures thereof.

22. The method of claim 12, wherein the acid compound and the salt of the fatty acid are present in the composition in a molar ratio of about 1 mol or more of the salt of the fatty acid to 1 mol of the acid compound.

23. The method of claim 12, wherein the additive composition is mixed with the thermoplastic polymer in an amount of about 500 parts or more per one million parts of the thermoplastic polymer.