# US 9,518,181 B2 · Renewable polyester compositions having a low density > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,518,181 B2 - Document ID: US9518181B2 - Status: Granted - Kind: B2 - Application number: 14/695,109 - Filed: 2015-04-24 - Published: 2015-08-13 - Granted: 2016-12-13 - Earliest claimed: 2012-02-10 - Assignees: Kimberly-Clark Worldwide, Inc. - Applicants: Kimberly-Clark Worldwide, Inc. - Inventors: Neil T. Scholl; Ryan J. McEneany; Thomas A. Eby; Vasily A. Topolkaraev - Web page: https://patentgrep.com/patent/US9518181B2 ## CPC - C08L 67/04: Polyesters derived from hydroxycarboxylic acids, e.g. lactones (C08L67/06 takes precedence) - C08L 23/02: not modified by chemical after-treatment - C08L 33/00: Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and only one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides or nitriles thereof; Compositions of derivatives of such polymers - C08L 63/00: Compositions of epoxy resins; Compositions of derivatives of epoxy resins - C08L 67/00: Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain (of polyester-amides C08L77/12; of polyester-imides C08L79/08); Compositions of derivatives of such polymers - C08L 71/00: Compositions of polyethers obtained by reactions forming an ether link in the main chain (of polyacetals C08L59/00; of epoxy resins C08L63/00; of polythioether-ethers C08L81/02; of polyether-sulfones C08L81/06); Compositions of derivatives of such polymers - C08L 23/0815: {with aliphatic 1-olefins containing one carbon-to-carbon double bond} - C08L 23/10: Homopolymers or copolymers of propene - C08L 2205/02: containing two or more polymers of the same C08L -group - C08L 2205/03: containing three or more polymers in a blend - C08L 2207/04: Thermoplastic elastomer - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract A thermoplastic composition that contains a rigid renewable polyester and has a voided structure and low density is provided. To achieve such a structure, the renewable polyester is blended with a polymeric toughening additive to form a precursor material in which the toughening additive can be dispersed as discrete physical domains within a continuous matrix of the renewable polyester. The precursor material is thereafter stretched or drawn at a temperature below the glass transition temperature of the polyester (i.e., “cold drawn”). This creates a network of voids located adjacent to the discrete domains, which as a result of their proximal location, can form a bridge between the boundaries of the voids and act as internal structural “hinges” that help stabilize the network and increase its ability to dissipate energy. The present inventors have also discovered that the voids can be distributed in a substantially homogeneous fashion throughout the composition. ## Claims ### Claim 1 A thermoplastic composition comprising a rigid polyester constituting 80 wt. % or more of the thermoplastic composition having a glass transition temperature of from 30° C. to 100° C., a polymeric toughening additive, and an interphase modifier comprising a silicone, silicone-polyether copolymer, alkylene glycol, alkane diol, amine oxide, fatty acid ester, or a combination thereof in an amount of from 0.1 wt. % to 15 wt. % based on the weight of the polyester, wherein the thermoplastic composition has a morphology in which a plurality of discrete primary domains and voids are dispersed within a continuous phase, the domains containing the polymeric toughening additive and the continuous phase containing the polyester, wherein the voids contain a combination of micro-voids having a dimension of about 1 micrometer or more and nano-voids having a dimension of less than about 1 micrometer, wherein the thermoplastic composition has a density of about 1.4 grams per cubic centimeter or less, and wherein the ratio of the glass transition temperature of the thermoplastic composition to the glass transition temperature of the polyester is from about 0.7 to about 1.3. ### Claim 2 (depends on 1) The thermoplastic composition of claim 1, wherein the composition has a density of from about 0.5 grams per cubic centimeter to about 0.95 grams per cubic centimeter. ### Claim 3 (depends on 1) The thermoplastic composition of claim 1, wherein the average percent volume of the composition that is occupied by the voids is from about 20% to about 80% per cubic centimeter. ### Claim 4 (depends on 1) The thermoplastic composition of claim 1, wherein the aspect ratio of the micro-voids is from about 0.1 to about 1. ### Claim 5 (depends on 1) The thermoplastic composition of claim 1, wherein the micro-voids have a dimension of about 1.5 micrometers or more. ### Claim 6 (depends on 1) The thermoplastic composition of claim 1, wherein the nano-voids have a dimension of from about 25 nanometers to about 500 nanometers. ### Claim 7 (depends on 1) The thermoplastic composition of claim 1, wherein the polyester includes polylactic acid, polyethylene terephthalate, or a combination thereof. ### Claim 8 (depends on 1) The thermoplastic composition of claim 1, wherein the polyester has a glass transition temperature of from about 50° C. to about 75° C. ### Claim 9 (depends on 1) The thermoplastic composition of claim 1, wherein the ratio of the solubility parameter for the polyester to the solubility parameter of the polymeric toughening additive is from about 0.5 to about 1.5, the ratio of the melt flow rate for the polyester to the melt flow rate of the polymeric toughening additive is from about 0.2 to about 8, and the ratio of the Young's modulus elasticity of the polyester to the Young's modulus of elasticity of the polymeric toughening additive is from about 2 to about 500. ### Claim 10 (depends on 1) The thermoplastic composition of claim 1, wherein the polymeric toughening additive includes a polyolefin. ### Claim 11 (depends on 10) The thermoplastic composition of claim 10, wherein the polyolefin is a propylene homopolymer, propylene/α-olefin copolymer, ethylene/α-olefin copolymer, or a combination thereof. ### Claim 12 (depends on 1) The thermoplastic composition of claim 1, wherein the polymeric toughening additive constitutes from about 1 wt. % to about 30 wt. % based on the weight of the polyester. ### Claim 13 (depends on 1) The thermoplastic composition of claim 1, wherein the interphase modifier has a kinematic viscosity of from about 0.7 to about 200 centistokes, determined at a temperature of 40° C. ### Claim 14 (depends on 1) The thermoplastic composition of claim 1, wherein the interphase modifier is hydrophobic. ### Claim 15 (depends on 1) The thermoplastic composition of claim 1, wherein the interphase modifier is an alkane diol, a fatty acid ester, or a combination thereof. ### Claim 16 (depends on 1) The thermoplastic composition of claim 1, wherein the interphase modifier constitutes from 1 wt. % to 10 wt. % based on the weight of the polyester. ### Claim 17 (depends on 1) The thermoplastic composition of claim 1, wherein the composition comprises a polyepoxide modifier that includes an epoxy-functional (meth)acrylic monomeric component. ### Claim 18 (depends on 1) The thermoplastic composition of claim 1, wherein the polyester constitutes from about 80 wt. % to about 99 wt. % of the thermoplastic composition. ### Claim 19 (depends on 1) The thermoplastic composition of claim 1, wherein the composition exhibits a Poisson coefficient of about 0.1 or less. ### Claim 20 (depends on 1) The thermoplastic composition of claim 1, wherein the composition exhibits an lzod notched impact strength of about 1 J/cm or more, measured at 23° C. according to ASTM D256-10 (Method A). ### Claim 21 (depends on 1) The thermoplastic composition of claim 1, wherein the composition exhibits a tensile elongation at break of about 40% or more, measured at 23° C. according to ASTM D638-10. ### Claim 22 (depends on 1) The thermoplastic composition of claim 1, wherein the composition has an average surface roughness of about 0.2 μm or more.