Transparent polypropylene compositions for thermoforming

Abstract

Disclosed are polymer compositions comprising at least 95% by weight of a polypropylene copolymer and 50 ppm to 2000 ppm of an arylamide-containing clarifier or a phosphate ester salt-containing clarifier, or a combination thereof, methods of making the polymer compositions, and articles comprising the polymer compositions, wherein the polymer compositions have a haze value A after one extrusion and a haze value B after five extrusions, the ratio of A to B being between 1 and 1.35, and A is less than 25%, and A and B are specified according to ASTM D1003 at a thickness of about 40 mils.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Application No. 63 / 046,491, filed June 30, 2020, which is incorporated herein by reference in its entirety for all purposes.

[0002] A. Field of the Invention FIELD OF THE INVENTION The present invention relates generally to polypropylene-containing polymer compositions that are capable of maintaining clarity after being subjected to multiple extrusions. [Background technology]

[0003] B. Description of related fields Polypropylene is used in several industries. For example, polypropylene-containing compositions are used in consumer goods packaging, electrical, equipment manufacturing, automotive, and other industrial plastic parts, home appliances, specialty devices such as living hinges, and textiles. In some applications, such as food storage containers, cups, and lids, good transparency is desired in manufactured articles made from polypropylene.

[0004] One of the problems associated with making manufactured articles from polypropylene-based compositions can be waste and / or reduced transparency. For example, a typical method for producing such manufactured articles involves thermoforming an extruded polypropylene sheet in a tool to form a thermoformed article. Typically, after the thermoforming process, a portion(s) of the extruded sheet is removed from the tool and sold, while the remaining portion can be recycled and re-extruded to form additional extruded sheets to avoid waste. Unfortunately, however, the recycled portion typically suffers from reduced transparency due to the extrusion process. The extrusion process typically introduces energy in the form of heat and / or pressure. This energy can cause the recycled portion to have reduced transparency compared to the originally produced extruded sheet. One way to address this reduced transparency is to avoid using recycled materials, especially when high transparency is desired for the resulting article. Simply put, the reduced transparency due to multiple extrusion steps can result in waste, which can increase manufacturing costs. US Patent No. 5,949,999 provides a discussion of how subjecting a given polymer resin to multiple extrusion processes can affect the resin's properties. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] U.S. Patent No. 10,414,086 Summary of the Invention

[0006] A discovery has been made that provides a solution to at least some of the problems described above. In one aspect, the solution can include providing a composition comprising a polypropylene copolymer in combination with a specific amount of an arylamide-containing clarifier and / or a phosphate ester salt-containing clarifier. It has been discovered that this combination can provide a polypropylene-based composition with a relatively low initial haze and with minimal or no increase in haze after multiple extrusion processes. Thus, the composition of the present invention can be recycled without compromising the haze value of thermoformed manufactured products that are made using recycled materials. In comparison, when a polypropylene copolymer is combined with other clarifiers (e.g., sorbitol-containing clarifiers), a substantial increase in haze can occur after multiple extrusion processes. The present application As illustrated in the non-limiting examples, a polymer composition of the present invention containing at least 95% by weight of a polypropylene copolymer and 50 ppm to 2000 ppm of an arylamide-containing clarifier and / or a phosphate ester salt-containing clarifier can have a haze value A and a haze value B, where the ratio of the haze value A after one extrusion to the haze value B after five extrusions, A to B, is 1 to 1.35. The haze values ​​for A and B can be determined according to ASTM D1003 (HazeGard) at a thickness of approximately 40 mils. An advantage of the present invention is that a portion of the material removed from an extruded polypropylene sheet that has been thermoformed into a manufactured article can be recycled and re-extruded to form another extruded sheet or film, with minimal or no loss in transparency of the extruded sheet containing this recycled material. That is, the polymer composition can be recycled without sacrificing transparency, which can help increase the cost efficiency of the manufacturing process.

[0007] One aspect of the present invention relates to a polymer composition. The polymer composition can contain at least 95% by weight of a polypropylene copolymer and 50 ppm to 2000 ppm of an arylamide-containing clarifier, a phosphate ester salt-containing clarifier, or a combination thereof. The polymer composition can have a haze value A and a haze value B, where the ratio of the haze value A after one extrusion to the haze value B after five extrusions, A to B, can be 1 to 1.35. In some embodiments, A can be less than 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, or even lower. A and B can be determined according to ASTM D1003 for a 40 mil thick molded specimen containing the polymer composition. In some embodiments, the ratio of A to B can be 1 to 1.32. In some embodiments, the ratio of A to B can be 1 to 1.1. In some embodiments, A can be less than 15%. In some specific embodiments, the ratio of A to B can be 1.03 to 1.07, and A can be less than 14%. In some specific embodiments, the polymer composition can include 50 ppm to 400 ppm of an arylamide-containing clarifier. In some specific embodiments, the arylamide-containing clarifier can be 1,3,5-tris(2,2-dimethylpropanamido)benzene. In some specific embodiments, the polymer composition can include 500 ppm to 1500 ppm of a phosphate ester salt-containing clarifier. In some specific embodiments, the phosphate ester salt-containing clarifier can be sodium and / or lithium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate. In some embodiments, the polymer composition can comprise 96% to 99.9% by weight, or 97% to 99.9% by weight, or 98% to 99.9% by weight, or 99% to 99.9% by weight of a polypropylene copolymer. In some embodiments, the polypropylene copolymer can be a propylene-ethylene random copolymer. In some specific embodiments, the polypropylene copolymer can be an isotactic propylene-ethylene random copolymer.In some embodiments, the propylene-ethylene random copolymer can comprise 0.1% to 5%, or 0.1% to 3%, or 0.1% to 2% by weight of ethylene units and 95% to 99.9%, or 97% to 99.9%, or 98% to 99.9% by weight of propylene units, based on the total weight of the copolymer. In some embodiments, the polypropylene copolymer, e.g., a propylene-ethylene random copolymer, e.g., an isotactic propylene-ethylene random copolymer, has a) a xylene soluble content of less than 8 wt%, such as from 1 wt% to 4 wt%, b) a melt flow rate (MF) at 230°C, 2.16 kg of from 0.1 g / 10 min to 150 g / 10 min, or from 1 to 60 g / 10 min, or from 1 to 30 g / 10 min, or from 1 to 10 g / 10 min, or from 1 to 7 g / 10 min, as measured according to ASTM D-1238; c) a MF of from 0.90 g / cc to 0.93 g / cc, or from 0.90 g / cc to 0.92 g / cc, or from 0.90 g / cc to 0.91 g / cc, as measured according to ASTM D792; or d) a MF of from 3 to 1 g / cc, as measured according to ASTM D-792. 5, or a polydispersity (Mw / Mn) thereof, or a combination thereof.

[0008] In some specific embodiments, the polymer composition can contain 99% to 99.9% by weight of a propylene-ethylene random copolymer and 500 ppm to 1500 ppm of a phosphate salt-containing clarifier, such as sodium or lithium 2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate, where the ratio of A to B can be 1 to 1.32 and A can be less than 20%. In some specific embodiments, the polymer composition can contain 99% to 99.9% by weight of a propylene-ethylene random copolymer and 50 ppm to 400 ppm of an arylamide-containing clarifier, such as 1,3,5-tris(2,2-dimethylpropanamido)benzene, where the ratio of A to B can be 1.03 to 1.07 and A can be less than 14%. In some embodiments, the polymer composition can further contain one or more additives selected from antioxidants, stabilizers, neutralizers, and antistatic agents. In some embodiments, the antioxidant can be a sterically hindered phenol. In certain embodiments, the antioxidant can be pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate. In certain embodiments, the polymer composition can contain 50 ppm to 500 ppm of an antioxidant, for example, a sterically hindered phenol, for example, pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate. In some embodiments, the stabilizer can be a phosphite-containing stabilizer. In certain embodiments, the stabilizer can be tris(2,4-di-tert-butylphenyl)phosphite. In certain embodiments, the polymer composition can contain 200 ppm to 2000 ppm of a stabilizer, for example, a phosphite-containing stabilizer, such as tris(2,4-di-tert-butylphenyl)phosphite. In some embodiments, the antistatic agent can be an ester-containing antistatic agent. In some particular embodiments, the antistatic agent can be glycerol monostearate.In certain embodiments, the antistatic agent can be glycerol monostearate having a monoester content of 45 to 90% by weight. In some embodiments, the polymer composition can contain 200 ppm to 2000 ppm of an antistatic agent, for example, an ester-containing antistatic agent, such as glycerol monostearate. In some embodiments, the neutralizing agent can contain a stearate salt. In some embodiments, the neutralizing agent can be calcium stearate and / or zinc stearate. In some embodiments, the polymer composition can contain 100 ppm to 1000 ppm of a neutralizing agent, for example, a stearate salt, such as calcium stearate and / or zinc stearate. In some embodiments, the polymer composition may have a melt flow rate (MFR) of 0.1 g / 10 min to 150 g / 10 min, or 1 to 60 g / 10 min, or 1 to 30 g / 10 min, or 1 to 20 g / 10 min, or 1 to 10 g / 10 min at 230° C. and 2.16 kg, as measured according to ASTM D-1238. In some embodiments, an injection-molded plaque comprising the polymer composition has a yellowness index (YI) of -2.7 to -2, as measured according to ASTM D-6290 at a thickness of 0.5 inches or greater. In some embodiments, the polymer composition may be an extrusion, blow molding, injection molding, and / or thermoforming composition. In some embodiments, the polymer composition may be an extruded sheet or film. In some embodiments, the composition may be included in an article of manufacture. In some embodiments, the article of manufacture may be transparent. In some embodiments, the article of manufacture may be a thermoformed article. In some embodiments, the article of manufacture is household food storage containers, cookware, plates, cups, cavity trays, drinking glasses, measuring cups, strainers, turkey basters, non-food storage containers, filing cabinets, shelving drawers, general storage devices, organizers, carrier bags, sweater boxes, rigid packaging, deli containers, deli container lids, dairy containers, dairy container lids, personal care product bottles and jars, furniture, furniture parts, building materials and construction container parts, films, paints, fibers, bags, adhesives, yarns, and fiber bliss. The container may be a box, a container, or a clamshell container.

[0009] Another embodiment relates to a method for making a thermoformed article. The method can include (1) melt-extruding a polymer composition of the present invention to form an initial article (e.g., an extruded polymer sheet or film); and (2) thermoforming at least a first portion of the initial article in a tool to form a thermoformed article. During thermoforming of the initial article, the initial article, while in a semi-solid form, can be stretched in one or more directions. After thermoforming, the thermoformed article, e.g., an article with a desired shape, can be recovered from the tool. The initial article can be an extruded sheet and / or a film. Thermoforming of the extruded sheet creates one or more waste portions in the extruded sheet, e.g., non-thermoformed portions and / or web portions. In some embodiments, the waste portion(s) can be scraped off and / or reclaimed and melt-extruded to form additional extruded sheets. In some embodiments, the additional extruded sheets can have substantially the same clarity and haze as the extruded sheet without the use of additional additives or energy. In some embodiments, the further extruded sheet and the extruded sheet have haze values ​​within 10% or 5% of each other when measured at the same thickness and under the same conditions. In some embodiments, the further extruded sheet contains one or more waste portions and a non-recycled composition comprising any one of the polymer compositions of the present invention.

[0010] Other embodiments of the invention are contemplated throughout this application. Any embodiment discussed with respect to one aspect of the invention equally applies to other aspects of the invention, and vice versa. Each embodiment described herein is understood to be an embodiment of the invention that is applicable to other aspects of the invention. It is contemplated that any embodiment or aspect discussed herein can be combined with any other embodiment or aspect discussed herein and / or implemented with respect to any method or composition of the invention, and vice versa. Furthermore, the compositions and systems of the invention can be used to achieve the methods of the invention.

[0011] Listed below are definitions of various terms and phrases used throughout this specification.

[0012] The terms "about" or "approximately" are defined as close as would be understood by one of ordinary skill in the art. In one non-limiting embodiment, these terms are defined as within 10%, otherwise within 5%, otherwise within 1%, and otherwise within 0.5%.

[0013] The terms "wt. %, "vol. %, " or "mole %" refer to the weight percentage, volume percentage, or mole percentage of a component, respectively, based on the total weight, volume, or moles of material, including the component. In one non-limiting example, 10 grams of a component in 100 grams of material is 10% of the component by weight. The term "ppm" refers to the parts of the component in parts per million by weight, based on the total weight, including the component.

[0014] The term "substantially" and variations thereof are defined to include ranges of within 10%, within 5%, within 1%, or within 0.5%.

[0015] The terms "inhibit" or "reduce" or "prevent" or "avoid" or variations of these terms, when used in the claims and / or specification, include any measurable reduction or complete inhibition that achieves the desired result.

[0016] The term "effective" means the effective use of the term as it is used in the specification and / or claims. "According to the present invention, the term "effective" means adequate to accomplish a desired, expected, or intended result.

[0017] The use of the words "a" and "an," when used in conjunction with any of the terms "comprising," "including," "containing," or "having" in the claims or the specification, may mean "one," but is also consistent with the meanings "one or more," "at least one," and "one or more."

[0018] The phrase "and / or" can include "and" or "or." By way of example, A, B, and / or C can include: A alone, B alone, C alone, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C.

[0019] The words "comprising" (and all forms of comprising, e.g., "comprise" and "comprises"), "having" (and all forms of having, e.g., "have" and "has"), "including" (and all forms of including, e.g., "includes" and "include"), or "containing" (and all forms of containing, e.g., "contains" and "contain") are inclusive or open-ended and do not exclude additional, unlisted elements or method steps.

[0020] The processes and systems of the present invention can "comprise," "consist essentially of," or "consist of" the specific ingredients, components, compositions, steps, etc. disclosed throughout this specification. With respect to the transitional phrase "consist essentially of," in one non-limiting aspect, a basic and novel property of the compositions and processes of the present invention is a polymer composition that can exhibit limited or no increase in haze value after being subjected to multiple extrusions.

[0021] Other objects, features, and advantages of the present invention will become apparent from the following drawings, detailed description, and examples. It should be understood, however, that the drawings, detailed description, and examples, while indicating specific embodiments of the present invention, are given by way of illustration only and are not meant to be limiting. Furthermore, it is contemplated that changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description. In further embodiments, features of specific embodiments can be combined with features of other embodiments. For example, features of one embodiment can be combined with features in any of the other embodiments. In further embodiments, additional features can be added to the specific embodiments described herein.

[0022] Advantages of the present invention will become apparent to those skilled in the art from the following detailed description and by reference to the accompanying drawings. [Brief explanation of the drawings]

[0023] [Figure 1] Percentage increase in haze for plaques containing compositions C-1 to C-6 after autoclaving for 30 minutes at 130° C. While the invention is susceptible to various modifications and variations, specific embodiments thereof are shown by way of example in the drawings. The drawings are not necessarily to scale. DETAILED DESCRIPTION OF THE INVENTION

[0024] A discovery has been made that provides a solution to at least some of the above-mentioned problems associated with polypropylene compositions used in thermoforming. In one embodiment, the discovery can include a polymer composition containing at least 95 wt. % polypropylene copolymer and 50 ppm to 2000 ppm of an arylamide-containing clarifier or a phosphate ester salt-containing clarifier, or a combination thereof. As illustrated in the non-limiting examples, the polypropylene-containing polymer composition of the present invention has low haze values ​​and exhibits relatively little increase in haze even after multiple extrusion steps. This may increase the recyclability of the composition of the present invention and may help reduce waste typically associated with thermoforming processes.

[0025] These and other non-limiting aspects of the present invention are described in further detail in the following sections.

[0026] A. Polymer Composition The polymer composition of the present invention can include: i) at least 95 wt.%, e.g., 95 wt.% to 99.9 wt.%, or at least one of, equal to, or between any two of 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, and 99.9 wt.%, a polypropylene copolymer; and ii) 50 ppm to 2000 ppm, or at least one of, equal to, or between any two of 50, 100, 200, 300, 400, 500, 600, 800, 1000, 1200, 1400, 1600, 1800, and 2000 ppm, of an arylamide-containing clarifier or a phosphate ester salt-containing clarifier, or a combination thereof. In some embodiments, the polymer composition of the present invention can comprise at least 95 wt%, e.g., 95 wt% to 99.9 wt%, or 96 wt% to 99.9 wt%, or 97 wt% to 99.9 wt%, or 98 wt% to 99.9 wt%, or 99 wt% to 99.9 wt% of a polypropylene copolymer, and 50 ppm to 400 ppm or 100 ppm to 300 ppm of an arylamide-containing clarifier. In some embodiments, the polymer composition of the present invention can comprise at least 95 wt%, e.g., 95 wt% to 99.9 wt%, or 96 wt% to 99.9 wt%, or 97 wt% to 99.9 wt%, or 98 wt% to 99.9 wt%, or 99 wt% to 99.9 wt% of a polypropylene copolymer, and 500 ppm to 1500 ppm or 800 ppm to 1200 ppm of a phosphate ester salt-containing clarifier.

[0027] The polymer composition can have a haze value A after one extrusion and a haze value B after five extrusions, where the ratio of A to B can be 1 to 1.35, or at least one of, equal to, or between two of 1, 1.03, 1.05, 1.07, 1.1, 1.15, 1.2, 1.25, 1.3, 1.32, 1.33, and 1.35, and A can be less than 25%, less than 20%, less than 15%, or less than 14%, for example, 13%, or 15%, or between 13% and 20%. In some embodiments, the polymer composition can have a haze value C after three extrusions, where the ratio of A to C can be 1 to 1.15 or 1 to 1.01. In some embodiments, the ratio of C to B can be 1 to 1.15 or 1 to 1.01. Haze values ​​can be determined (by HazeGard) according to ASTM D1003 using molded articles containing the polymeric composition at a thickness of about 40 mils. A, B, and / or C can be determined with extrusion pass parameters set and / or performed under conditions similar (e.g., within ±5%) to the respective conditions presented in Tables 4 and 5.

[0028] 1. Polypropylene copolymer The polypropylene copolymer can be a propylene-ethylene random copolymer. In some particular embodiments, the polypropylene copolymer can be an isotactic propylene-ethylene random copolymer. In some embodiments, the propylene-ethylene random copolymer, e.g., an isotactic propylene-ethylene random copolymer, can comprise, based on the total weight of the copolymer, 0.1 wt% to 5 wt%, or 0.1 wt% to 3 wt%, or 0.1 wt% to 2 wt%, or at least any one of, equal to, or between any two of 0.1, 0.2, 0.4, 0.6, 0.8, 1, 2, 3, 4, and 5 wt% ethylene units, and 95 wt% to 99.9 wt%, or 97 wt% to 99.9 wt%, or 98 wt% to 99.9 wt%, or at least any one of, equal to, or between any two of 95, 96, 97, 98, 99, 99.2, 99.4, 99.6, 99.8, and 99.9 wt% propylene units. In some embodiments, the polypropylene copolymer, e.g., a propylene-ethylene random copolymer, can have a xylene soluble content of less than 8 wt%, e.g., 1 wt% to 4 wt%, or at least one of, equal to, or between any two of 1, 2, 3, and 4 wt%. In some embodiments, the polypropylene copolymer, e.g., a propylene-ethylene random copolymer, can have a polydispersity (Mw / Mn) of 3 to 15, or at least one of, equal to, or between any two of 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, and 15, where the polydispersity is measured using gel permeation chromatography (GPC).In some embodiments, the polypropylene copolymer, e.g., a propylene-ethylene random copolymer, can have a melt flow rate (MFR) at 230° C. and 2.16 kg of 0.1 g / 10 min to 150 g / 10 min, or 1 to 60 g / 10 min, or 1 to about 30 g / 10 min, or 1 to about 10 g / 10 min, or 1 to about 7 g / 10 min, or at least any one of, equal to, or between any two of 0.1, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, and 160 g / 10 min, as measured according to ASTM D-1238. In some embodiments, the polypropylene copolymer, e.g., a propylene-ethylene random copolymer, can have a density of 0.90 g / cc to 0.93 g / cc, or 0.90 g / cc to 0.92 g / cc, or 0.90 g / cc to 0.91 g / cc, or at least any one of, equal to, or between any two of 0.9, 0.902, 0.904, 0.906, 0.908, 0.91, 0.915, 0.92, 0.925, and 0.93 g / cc, as measured according to ASTM D792. In some embodiments, the polypropylene copolymer, e.g., a propylene-ethylene random copolymer, can have a combination or all of the properties mentioned herein.

[0029] Polypropylene copolymers can be prepared via conventional polymerization processes, such as those known in the art. Examples of such polymerization processes include slurry polymerization, liquid bulk polymerization, and gas-phase polymerization. In a slurry polymerization process, polymerization occurs in a loop or continuous stirred tank reactor in the presence of a solvent, such as hexane. Polymerization can also be carried out via bulk-phase polymerization, in which liquid propylene and ethylene serve as both monomers and diluents. A typical bulk process generally uses one or more loop reactors. In another aspect, copolymers can be produced by gas-phase polymerization of propylene and ethylene, which gas-phase polymerization is typically carried out in a fluidized-bed reactor. The flocculent or powdery polymer produced from the polymerization reaction can be removed from the reactor and then processed by conventional techniques, such as extrusion, to produce the desired copolymer pellets. The amount of ethylene monomer used during copolymer polymerization is desirably proportional to the final ethylene content desired in the target propylene copolymer. Depending on the method, the ethylene content in the polymerization can range from 0.1 to 5 wt%, or 0.1 to about 3 wt%, or 0.1 to about 2 wt%, based on the total weight of the monomers, e.g., ethylene and propylene, present in the polymerization. In some embodiments, polypropylene copolymers, e.g., propylene-ethylene random copolymers, can be prepared using metallocene catalysts or Ziegler-Natta catalysts.

[0030] Ziegler-Natta catalysts, well known in the art and useful for preparing isotactic polypropylene, can be prepared by combining a transition metal halide, such as titanium, chromium, or vanadium, with a metal hydride and / or metal alkyl, typically an organoaluminum compound, as a cocatalyst. In some embodiments, the catalyst can contain a titanium halide supported on a magnesium compound. Ziegler-Natta catalysts, such as titanium tetrachloride (TiCl4) supported on an activated magnesium dihalide, such as magnesium dichloride or magnesium dibromide, are supported catalysts, as disclosed in U.S. Pat. Nos. 4,298,718 and 4,544,717 (both to Mayr et al., which are incorporated herein by reference). Silica can also be used as a support. The supported catalyst can be used in conjunction with a cocatalyst or electron donor, such as alkyl aluminum compounds, such as triethyl aluminum (TEAL), trimethyl aluminum (TMA), and triisobutyl aluminum (TIBAL).

[0031] 2. Clarifying agent The polymer composition of the present invention comprises a phosphate ester salt-containing clarifier and / or an arylamide-containing clarifier.

[0032] Non-limiting examples of phosphate ester salt-containing fining agents include 2,2-methylene-bis(4,6-di-tert-butylphenyl)phosphate and / or hydroxybis(2,4,8,10-tetrakis(1,1-dimethyl)6-hydroxy-12H-dibenzo[d,g][1,2,3][dioxaphosphocin 6-oxidato]aluminum. In certain embodiments, the fining agent can be 2,2-methylene-bis(4,6-di-tert-butylphenyl)phosphate. Examples of commercially available phosphate ester salt-containing fining agents include, without limitation, ADK Stabilizer NA-71 and ADK Stabilizer NA-21, both of which are available from Amfine Chemical Corp. (Allendale, NJ).

[0033] A non-limiting example of an arylamide-containing fining agent can be a 1,3,5-benzenetrisamide derivative. In some embodiments, the arylamide-containing fining agent can be (1,3,5-tris(2,2-dimethylpropanamido)benzene). A commercially available example of an arylamide-containing fining agent includes, without limitation, IRGACLEAR XT 386 available from BASF.

[0034] The polymer compositions of the present invention can be free or essentially free of clarifiers containing sorbitol or sorbitol derivatives, nonitol or nonitol derivatives, and / or xylitol or xylitol derivatives, for example, containing less than 100 ppm, or less than 50 ppm, or less than 10 ppm.

[0035] 3. Additives In some embodiments, the polymer composition may contain one or more additives selected from antioxidants, stabilizers, neutralizing agents, processing aids, peroxides, slip agents, and / or antistatic agents.

[0036] In some embodiments, the polymer composition comprises: iii) 50 ppm to 500 ppm, or at least one of, equal to, or between any two of 50, 100, 200, 300, 400, and 500 ppm, of an antioxidant; iv) 200 ppm to 2000 ppm, or at least one of, equal to, or between any two of 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, and 2000 ppm, of a stabilizer; v) 200 ppm iv) an antistatic agent in an amount of from 100 ppm to 1000 ppm, or at least one of, equal to, or between any two of 200, 400, 600, 800, 1000, 1200, 1400, 1600, 1800, and 2000 ppm; or iv) a neutralizing agent in an amount of from 100 ppm to 1000 ppm, or at least one of, equal to, or between any two of 100, 200, 400, 600, 800, and 1000 ppm, or any combination thereof.

[0037] The antioxidant can be a sterically hindered phenol and / or a phosphite-containing antioxidant. Combinations of antioxidants can also be used. In some embodiments, the sterically hindered phenol antioxidant can be pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, octadecyl 3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate], or 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-1,3,5-triazine-2,4,6(1H,3H,5H)-trione, or any combination thereof. In some embodiments, the phosphite-containing antioxidant can be tris(2,4-di-tert-butylphenyl) phosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphate, or bis(2,4-di-t-butylphenyl)pentraerythritol diphosphate, or any combination thereof. In some specific embodiments, the antioxidant can be tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenylpropionic acid]pentaerythritol. The stabilizer can be a phosphite-containing stabilizer and / or an oligomeric hindered amine-containing stabilizer. In some embodiments, the phosphite-containing stabilizer can be tris(2,4-di-tert-butylphenyl) phosphite. In some embodiments, the oligomeric hindered amine-containing stabilizer can be a polymer of butanedioic acid, dimethyl ester, 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol. In some specific embodiments, the stabilizer can be tris(2,4-di-tert-butylphenyl)phosphite. In some embodiments, the antistatic agent can be glycerol monostearate.The glycerol monostearate can have a monoester content of 45-90% by weight, or at least one of, equal to, or between 45, 50, 55, 60, 65, 70, 75, 80, 85, and 90% by weight. The neutralizing agent can be a stearate-containing neutralizing agent, hydrotalcite, zinc oxide, or sodium benzoate, or any combination thereof. The stearate-containing neutralizing agent can be calcium stearate and / or zinc stearate. In certain embodiments, the neutralizing agent can be a stearate-containing neutralizing agent, such as calcium stearate and / or zinc stearate.

[0038] In some embodiments, the polymer composition comprises 50 ppm to 500 ppm of a sterically hindered phenol, such as pentaerythritol tetrakis[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionate, 200 ppm to 2000 ppm of ethylene phosphite, It may contain an ester-containing stabilizer such as tris(2,4-di-tert-butylphenyl) phosphite, 200 ppm to 2000 ppm of an ester-containing antistatic agent such as glycerol monostearate, or 100 ppm to 1000 ppm of a stearate salt such as calcium stearate and / or zinc stearate, or any combination thereof.

[0039] B. Polymer Composition Properties In some embodiments, the polymer composition may have a melt flow rate (MFR) of 0.1 g / 10 min to 150 g / 10 min, or 1 to 60 g / 10 min, or 1 to 30 g / 10 min, or 1 to 20 g / 10 min, or 1 to 10 g / 10 min, or 1 to 7 g / 10 min at 230° C. and 2.16 kg, as measured according to ASTM D-1238. In some embodiments, the polymer composition may have a flexural modulus of 100 Kpsi to 300 Kpsi at 4-8 N, as specified by ASTM D790-97. In some embodiments, the polymer composition may have a notched Izod impact strength of greater than 0.9 ft-lb / in, e.g., 1 ft-lb / in to 1.5 ft-lb / in, at 23° C., as measured according to D638. In some embodiments, the polymeric composition can have a tensile modulus of greater than 210 KPsi, e.g., from 211 KPsi to 300 KPsi, at 23° C., as measured according to D638. In some embodiments, the polymeric composition can have an elongation at break of greater than 180%, e.g., from 200% to 250%, at 23° C., as measured according to D-638. In some embodiments, the polymeric composition can have a crystallization temperature of about 100° C. to 135° C., or 115° C. to 130° C., or 120° C. to 125° C., as determined by differential scanning calorimetry (DSC) according to ASTM D-3418D.

[0040] In some embodiments, prior to any extrusion of the polymer composition in the extruder, the polymer composition may exhibit a Yellowness Index (YI) of less than 1, or between −5 and 0, or between −3 and −1.5, or between −2.7 and −2, as measured in accordance with ASTM D-6290. In certain embodiments, the YI may increase after one, two, three, four, or five extrusions of the polymer composition through an extruder slot or die at a temperature of about 545°F. By way of example and not limitation, after one, two, three, four, or five extrusions of the polymer composition through an extruder slot or die at a temperature of about 545°F, the YI may be in the range of −2 to 2.5, or −1.8 to 2, as measured in accordance with ASTM D-6290. In some embodiments, the polymer composition may exhibit a “Color L” of 60 to 85, 70 to 80, 72 to 78, or about 74, as measured in accordance with ASTM D-6290. In some embodiments, the polymeric composition can exhibit a "color a" of less than 1, less than 0, between -2 and 0, between -1 and 0, or between -0.7 and -0.2, as measured according to ASTM D-6290. In some embodiments, the polymeric composition can exhibit a "color b" of less than 1, less than 0, between -2 and 0, between -1 and 0, or between -0.9 and -0.3, as measured according to ASTM D-6290.

[0041] In some embodiments, prior to any extrusion of the polymer composition in the extruder, the polymer composition can exhibit an initial % haze (e.g., an initial haze is a haze that has never been subjected to an extrusion process) of less than 20%, less than 18%, less than 16%, or less than 15% when measured at a thickness of about 40 mm according to ASTM D1003. In certain embodiments, after one, two, three, four, or five extrusions of the polymer composition through the slot or die of the extruder at a temperature of about 545°F, the % haze when measured at a thickness of about 40 mils according to ASTM D1003 can change by about 30%, 20%, 10%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, or less based on the initial % haze. In some embodiments, the % change can be an increase in haze. In some embodiments, the % change can be a decrease in haze. .

[0042] In some embodiments, the polymer composition can have a combination or all of the properties mentioned herein.

[0043] C. Methods for preparing and thermoforming polymer compositions The polymer composition of the present invention can be produced by various methods known in the art, such as extrusion, injection molding, thermoforming, etc. For example, components such as a polypropylene copolymer, an arylamide-containing clarifier, and / or a phosphate ester salt-containing clarifier, and one or more additives can be mixed, such as by dry blending, and then wet blended, such as by extrusion, to form a polymer composition. The extruder used can be any type of extruder known in the art. The extrusion can be carried out at a temperature high enough to melt the composition, but as low as possible to avoid excessive thermal decomposition of the composition. In certain embodiments, the thermoplastic composition can be subjected to multiple successive passes through the extruder. Without wishing to be bound by theory, it is believed that subjecting the polymer resin to one or more passes through the extruder mimics accelerated degradation of the polymer resin due to the high pressure and high temperature the polymer resin encounters during extrusion. Again, without wishing to be bound by theory, it is believed that subjecting the polymer resin to a process of passing through an extruder mimics the reprocessing of polymer regrind trim in sheet extrusion thermoforming. In each process, the thermoplastic composition may be extruded through a slot or die. The extruded material may be quenched, if desired. For each extrusion, the final melt temperature before extrusion through the die may independently be 302 to about 600°F (150 to 315°C), and the pressure may independently range from about 100 to about 30,000 psi (0.7 to 207 mPa).

[0044] One embodiment relates to a method for forming a thermoformed article containing a polymer composition. The method can include melt-extruding components, such as a polypropylene copolymer, an arylamide-containing clarifier and / or a phosphate ester salt-containing clarifier, and one or more additives, to form an initial article, and thermoforming the initial article to form a thermoformed article. The initial article can be an extruded sheet or film containing the polymer composition. Thermoforming the initial article can include subjecting the initial article to heat, vacuum, or pressure, or a combination thereof, to convert the initial article into a thermoformed article. By way of example and not limitation, the initial article can be thermoformed by placing it in a parting tool. The initial article in the parting tool can be subjected to heat, vacuum, or pressure, or a combination thereof, which can cause the initial article to conform to the shape of the interior walls of the parting tool. In some embodiments, the initial article can be heated before being placed in the parting tool. The heated initial article can then be placed in a tool, the tool can be closed over the initial article, and then vacuum or pressure can be applied to the tool. Applying vacuum or pressure to the heated initial article in the tool causes the initial article to conform to the shape of the inner walls of the tool, thus forming a thermoformed article. The thermoformed article formed into a desired shape can be removed from the tool. Portions of the initial article that are not removed, such as the web of the sheet and / or waste portions of the sheet that were not thermoformed, can be scraped off, reused, and / or recycled to make a second initial article. The second initial article can be thermoformed to form another thermoformed article. The second initial article and the another thermoformed article can have haze values ​​comparable to those of the initial article and the first thermoformed shape. In other words, the polymer compositions and / or articles containing the polymer compositions of the present invention have stable haze values ​​even after being subjected to 2, 3, 4, 5, or more extrusion processes, which allows the articles containing the polymer compositions to be recycled with limited or no loss in transparency of the recycled parts or manufactured articles made from at least a portion of the recycled parts.

[0045] In some embodiments, the initial article can be formed by extruding the molten polymer composition through a slot or die and cooling, e.g., quenching the extrudate to form the initial article, e.g., an extruded sheet. Extrusion of the molten polymer composition can occur at a temperature ranging from 150°C to 315°C, or at least one of, equal to, or between any two of 150°C, 160°C, 170°C, 180°C, 190°C, 200°C, 210°C, 220°C, 230°C, 240°C, 250°C, 260°C, 270°C, 280°C, 290°C, 300°C, 310°C, and 315°C. In some embodiments, the extruded sheet can have a thickness of 0.5 to 100 mm, 12 to 20 mm, 12 to 16 mm, or 16 to 20 mm, or at least any one of, equal to, or between any two of 0.5, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm. In some embodiments, the initial article can be a multilayer extruded sheet, and each layer of the multilayer extruded sheet can independently have a thickness of 0.5 to 100 mm, 12 to 20 mm, 12 to 16 mm, or 16 to 20 mm, or at least any one of, equal to, or between any two of 0.5, 1, 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 90, and 100 mm. In some embodiments, the initial article can be a cast sheet or a stretched sheet.

[0046] In some embodiments, thermoforming the initial article subjects the initial article to solid-state orientation. In some embodiments, the stretched sheet can be reheated and thermoformed within a tool. As the stretched sheet conforms to the shape within the tool, it undergoes solid-state orientation in one or more directions, thereby forming a solid-state stretched thermoformed article from the stretched sheet.

[0047] D. Articles Containing Polymer Compositions The polymer compositions of the present invention can be included in an article of manufacture. The article of manufacture can be an extruded, blow molded, injection molded, and / or thermoformed article. In some embodiments, the article of manufacture can be transparent.

[0048] Non-limiting examples of articles of manufacture include household goods, food storage containers, cookware, plates, cups, measuring cups, drinking glasses, strainers, turkey basters, non-food storage containers, filing cabinets and particularly clear drawers used in such cabinets, general storage devices such as organizers, carrier bags, sweater boxes, films, paints and fibers, bags, adhesives, threads, textiles, bottles, jars, plates and cups, clamshell containers, and the like. Articles of manufacture can be rigid packaging, such as deli containers and lids, including those used for dips, spreads, and pasta salads; dairy containers, including those used to store cottage cheese, butter, and yogurt; personal care products; and bottles and jars. In these and other uses, resins may be combined with other materials, such as particulate materials, to form composites, including talc, calcium carbonate, wood, and fibers, such as glass or graphite fibers. Examples of such composites include furniture components, automotive parts, and building materials, particularly those used as wood substitutes. [Example]

[0049] The present invention will now be described in further detail by way of specific examples. The following examples are provided for illustrative purposes only and are not intended to limit the present invention in any way. Those skilled in the art will readily recognize a variety of non-critical parameters that can be changed or modified to produce essentially the same results. [Example]

[0050] Polymer compositions C-1 to C-6 were prepared with the compositions shown in Table 1. Compositions C-1 to C-6 were injection molded to ASTM specifications. The extrusion parameters used are listed in Table 2. The optical and mechanical properties of the compositions are listed in Table 3.

[0051] [Table 1]

[0052] [Table 2]

[0053] [Table 3-1]

[0054] [Table 3-2]

[0055] [Table 3-3]

[0056] Compositions C-1 through C-6 have similar stiffness and Izod impact strength. The crystallization temperatures (Tc) of the compositions are consistent with their nucleating agent / clarifying agent content. Inventive compositions C-4 and C-5 exhibit excellent haze values ​​despite using very low amounts of 1,3,5-tris(2,2-dimethylpropanamido)benzene and 2,2'-methylenebis(4,6-ditertbutylphenyl)phosphate as clarifiers, respectively. The haze values ​​of all samples increased after autoclaving at 130°C for 30 minutes. Composition C-5 exhibits the lowest "after / before haze" ratio. Figure 1 shows the percentage increase in haze after autoclaving compositions C-1 through C-6.

[0057] The properties of inventive compositions C-4 and C-5 were investigated with respect to multiple extrusions. The extrusion conditions used for C-4 and C-5 are presented in Tables 4 and 5, respectively. The properties of inventive compositions C-4 and C-5 after each step were measured and compared with those of C-6 (Table 6).

[0058] [Table 4]

[0059] [Table 5]

[0060] [Table 6]

[0061] The melt flow rate (MFR) and yellowness index (YI) of the compositions increased after each extrusion. For composition C-5, the increase in haze after multiple extrusions was modest, while for composition C-4, the haze remained roughly the same, around 15%, even after five extrusions. Overall, inventive compositions C4 and C5 exhibited excellent low haze values, with composition C-4 showing minimal change in haze after multiple regrinds and extrusions.

[0062] While the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions, and adjustments can be made therein without departing from the spirit and scope of the embodiments as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the processes, machines, manufacture, compositions of matter, means, methods, and steps described in the specification. As those skilled in the art will readily recognize from the above disclosure, there are available existing or later-developed processes, machines, manufacture, compositions of matter, means, methods, or steps that perform substantially the same function or achieve substantially the same results as the corresponding embodiments described herein. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. 1. A polymer composition comprising: at least 95% by weight of a polypropylene copolymer; 50 ppm to 2000 ppm of an arylamide-containing fining agent and a phosphate ester salt-containing fining agent; an antioxidant comprising a sterically hindered phenol; a stabilizer comprising a phosphite; an antistatic agent comprising an ester; Neutralizers containing stearates Including, the polymer composition has a haze value of A after one extrusion and a haze value of B after five extrusions, the ratio of B to A (B / A) being 1 to 1.35, A being less than 25%, and A and B being specified at a thickness of about 40 mils according to ASTM D1003; The polymer composition.

2. 2. The polymer composition of claim 1, wherein the ratio of B to A (B / A) is 1.03 to 1.07, and A is less than 15%.

3. 3. The polymer composition of claim 1, comprising 99% to 99.95% by weight of said polypropylene copolymer.

4. The polymer composition of any one of claims 1 to 3, wherein the polypropylene copolymer is an ethylene-propylene random copolymer.

5. 5. The polymer composition of claim 4, wherein the ethylene-propylene random copolymer comprises 0.1 wt. % to 5 wt. % ethylene units and 95 wt. % to 99.9 wt. % propylene units, based on the total weight of the copolymer.

6. 6. The polymer composition of any one of claims 1 to 5, wherein the polypropylene copolymer has a melt flow of 1 to 10 g / 10 min at 230°C and 2.16 kg as measured according to ASTM D-1238, and a density of 0.90 g / cc to 0.93 g / cc as measured according to D1505.

7. 10. The polymer composition of claim 1, comprising 50 ppm to 500 ppm of said antioxidant, 200 ppm to 2000 ppm of said stabilizer, 100 ppm to 1000 ppm of said neutralizing agent, and 200 ppm to 2000 ppm of said antistatic agent.

8. 8. The polymer composition of any one of claims 1 to 7, wherein an injection molded article comprising the polymer composition has a yellowness index (YI) of -2 to -2.7 at a thickness of 0.5 mm or greater, as measured according to ASTM D-6290.

9. 9. The polymer composition of claim 1, wherein the polymer composition is an extruded, blow molded, injection molded, and / or thermoformed molded article.

10. 10. The polymer composition of any one of claims 1 to 9, wherein the polymer composition is an extruded sheet and / or film.

11. The polymer composition of claim 1 , wherein the polymer composition is included in an article of manufacture.

12. 12. The polymer composition of claim 11, wherein the article of manufacture is transparent.

13. 13. The polymer composition of any one of claims 11 to 12, wherein the article of manufacture is a thermoformed article.

14. 14. The polymer composition of any one of claims 11 to 13, wherein the article of manufacture is a household food storage container, cookware, plate, cup, cavity tray, drinking glass, measuring cup, colander, turkey baster, non-food storage container, filing cabinet, shelving drawer, general storage device, organizer, carrier bag, sweater box, rigid packaging, deli container, deli container lid, dairy container, dairy container lid, personal care product bottles and jars, furniture, furniture parts, building materials and construction container parts, film, paint, fiber, bag, adhesive, yarn and fabric blister package, or clamshell container.

15. 1. A method of forming a thermoformed article, comprising: melt-extruding the polymer composition of any one of claims 1 to 8 to form an extruded sheet; thermoforming the extruded sheet in a tool to form the thermoformed article; The method comprising:

16. 1. A method of forming a thermoformed article, comprising: melt-extruding the polymer composition of any one of claims 1 to 8 to form a first extruded sheet; thermoforming the first extruded sheet in a tool to form a thermoformed article, wherein thermoforming the first extruded sheet creates one or more waste portions of the first extruded sheet; melt-extruding the one or more waste portions to form a further extruded sheet, the further extruded sheet having a haze within 10% of the first extruded sheet without the use of additional additives or energy; The method comprising:

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