# US 12,767,740 B2 · Monomodal propylene random copolymer with high impact strength > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,767,740 B2 - Document ID: US12767740B2 - Status: Granted - Kind: B2 - Application number: 18/029,333 - Filed: 2021-10-01 - Published: 2024-02-08 - Granted: 2026-10-20 - Earliest claimed: 2020-10-02 - Assignees: W.R. Grace & Co.-Conn. - Applicants: W.R. Grace & Co.-Conn - Inventors: Zhiru Ma; John K. Kaarto - Web page: https://patentgrep.com/patent/US12767740B2 ## CPC - C08F 210/06: Propene - B65D 65/38: Packaging materials of special type or form - C08K 5/0083: {Nucleating agents promoting the crystallisation of the polymer matrix} - C08L 23/16: Ethylene-propylene or ethylene-propylene-diene copolymers - C08F 2810/10: including a reactive processing step which leads, inter alia, to morphological and/or rheological modifications, e.g. visbreaking - C08L 23/26: modified by chemical after-treatment (saponified copolymers C08L23/0861; unsaturated acid salts C08L23/0876) - C08L 2023/42: {Depolymerisation, vis-breaking or degradation} - C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS - B65D: CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES - C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09) - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) ## Abstract Visbroken and monomodal random polypropylene copolymers are disclosed that have excellent impact resistance properties. Because the polymers are monomodal, the polymers also have excellent optical characteristics. In order to produce the polymers, a high molecular weight and low melt flow rate polypropylene polymer is combined with a visbreaking agent under molten conditions that has been found to dramatically improve impact resistance. ## Claims ### Claim 1 A polymer composition comprising: a monomodal, visbroken polypropylene polymer, the visbroken polypropylene polymer comprising a random propylene and alpha-olefin copolymer, the visbroken polypropylene polymer having a melt flow rate of less than about 10 g/10 min at 230° C. and at a load of 2.16 kg and a polydispersity index of from about 2.5 to about 4, the visbroken polypropylene polymer displays an Izod impact resistance at 23° C. of greater than about 400 J/m, the polymer composition optionally contains a nucleating agent. ### Claim 2 (depends on 1) The polymer composition of claim 1, wherein the polymer composition contains the nucleating agent, the polymer composition displays a haze at 1 mm of less than about 15%. ### Claim 3 (depends on 1) The polymer composition of claim 1, wherein the visbroken polypropylene polymer has a melt flow rate of from about 0.8 g/10 min to about 4 g/10 min, and the visbroken polypropylene polymer has a cracking ratio of from about 4 to about 20. ### Claim 4 (depends on 1) The polymer composition of claim 1, wherein the visbroken polypropylene polymer has a melt flow rate of from about 0.4 g/10 min to about 1.5 g/10 min, and the visbroken polypropylene polymer has a cracking ratio of from about 2 to about 8. ### Claim 5 (depends on 1) The polymer composition of claim 1, wherein the random propylene and alpha-olefin copolymer is a propylene and ethylene random copolymer. ### Claim 6 (depends on 1) The polymer composition of claim 1, wherein the random propylene and alpha-olefin copolymer contains the alpha-olefin in an amount from about 2.5% by weight to about 5.5% by weight. ### Claim 7 (depends on 1) The polymer composition of claim 1, wherein the visbroken polypropylene polymer has a xylene solubles content of greater than about 5%. ### Claim 8 (depends on 1) The polymer composition of claim 1, wherein the visbroken polypropylene polymer displays an Izod impact resistance of greater than about 450 J/m and less than about 1100 J/m. ### Claim 9 (depends on 2) The polymer composition of claim 2, wherein the nucleating agent comprises a nonitol, a sorbitol, a phosphate ester, and a dicarboxylate metal salt, or mixtures thereof, the nucleating agent is present in the polymer composition in an amount greater than about 400 ppm and less than about 5000 ppm. ### Claim 10 (depends on 1) The polymer composition of claim 1, wherein the polymer composition contains the visbroken polypropylene polymer in an amount greater than about 70% by weight. ### Claim 11 (depends on 1) The polymer composition of claim 1, wherein the random propylene and alpha-olefin copolymer comprises a random propylene and ethylene copolymer containing ethylene in an amount of from about 3.7% to about 4.6% by weight, the visbroken polypropylene polymer has a xylene solubles content of from about 8% to about 15% by weight, the visbroken polypropylene polymer has a melt flow rate of from about 0.6 g/10 min to about 4 g/10 min, and the polymer composition contains a nucleating agent and wherein the polymer composition displays a haze at 1 mm of less than about 15%. ### Claim 12 (depends on 1) The polymer composition of claim 1, wherein the visbroken polypropylene polymer is Ziegler-Natta catalyzed using a phthalate-free catalyst. ### Claim 13 (depends on 1) The polymer composition of claim 1, wherein the visbroken polypropylene polymer has a molecular weight distribution of less than about 5. ### Claim 14 (depends on 1) A molded article formed from the polymer composition of claim 1. ### Claim 15 (depends on 14) The molded article of claim 14, wherein the molded article is an injection molded article, an extrusion blow molded article or a thermoformed article. ### Claim 16 (depends on 1) A storage container formed from the polymer composition of claim 1. ### Claim 17 (depends on 16) The storage container of claim 16, wherein the storage container comprises food packaging or a bottle. ### Claim 18 A method of preparing a visbroken polypropylene polymer comprising visbreaking a monomodal polypropylene polymer, the monomodal polypropylene polymer comprising a random propylene and alpha-olefin copolymer, wherein the monomodal polypropylene polymer has an initial melt flow rate of less than about 0.5 g/10 min at 230° C. and at a load of 2.16 kg, the random propylene and alpha-olefin copolymer contains the alpha-olefin in an amount of from about 2.5% to about 5.7% by weight, the visbroken polypropylene polymer has a xylene soluble content of from about 6% to about 20% by weight, and wherein the monomodal polypropylene polymer is visbroken so as to achieve a cracking ratio of greater than 3, the visbroken polypropylene polymer has an Izod impact resistance at 23° C. of greater than about 400 J/m. ### Claim 19 (depends on 18) The method of claim 18, wherein the polypropylene polymer is a random propylene and ethylene copolymer. ### Claim 20 (depends on 18) The method of claim 18, wherein the visbroken polypropylene polymer is a monomodal polymer.