RU-2861729-C1 - COMPOSITION FOR PRODUCING UV-CROSSLINKED PIPES

Abstract

FIELD: chemical industry. SUBSTANCE: invention relates to polyethylene compositions intended for the production of pipes. A composition for producing UV-crosslinked pipes is proposed, containing, parts by weight: high-density polyethylene from 70 to 95; ethylene-glycidyl methacrylate copolymer from 5 to 30; glycidyl-functional organosiloxane coagent from 0.3 to 3.0; phosphine oxide photoinitiator from 0.15 to 0.40; α-hydroxyketone photoinitiator from 0.05 to 0.30; hydroxyphenyltriazine UV absorber from 0.10 to 0.50; polymeric hindered amine light stabiliser from 0.20 to 0.70; phenolic antioxidant from 0.05 to 0.20; phosphite antioxidant from 0.05 to 0.20; thioether antioxidant from 0.05 to 0.20. EFFECT: obtaining a polymer composition based on high-density polyethylene, ensuring the formation of a uniformly UV-crosslinked three-dimensional network structure in the volume of a pipe or other pipe product and possessing a set of improved performance characteristics. 1 cl, 2 tbl, 3 ex

Inventors

• Bojkov Vitalij Nikolaevich

Dates

Publication Date

20260508

Application Date

20251210

Claims (1)

1. A composition for producing UV-crosslinked pipes, comprising, in parts by weight: high-density polyethylene from 70 to 95; ethylene-glycidyl methacrylate copolymer from 5 to 30; glycidyl-functional organosiloxane coupling agent from 0.3 to 3.0; phosphine oxide photoinitiator from 0.15 to 0.40; α-hydroxyketone photoinitiator from 0.05 to 0.30; hydroxyphenyltriazine UV absorber from 0.10 to 0.50; polymeric light stabilizer of the hindered amine class from 0.20 to 0.70; phenolic antioxidant from 0.05 to 0.20; phosphite antioxidant from 0.05 to 0.20; thioether antioxidant from 0.05 to 0.20.

Description

The invention pertains to the field of polymeric materials, specifically to polyolefin-based compositions intended for the production of articles subject to ultraviolet (UV) crosslinking. More specifically, the invention concerns polymer compositions based on high-density polyethylene containing photochemical initiators and functional coagents that ensure the formation of a three-dimensional network structure upon exposure to UV radiation. The composition is intended for the production of UV-crosslinked pipes and other tubular products exposed to solar radiation and climatic factors, where high durability, ageing resistance, dimensional stability, and increased mechanical strength are required. UV-cross-linked pipes produced from the claimed composition can be used in the production of technical, drainage, and ventilation pipes, pipes for transporting liquid and gaseous media, pipeline components, as well as containers and large-sized polymer products for outdoor use. Products based on this composition exhibit UV radiation resistance, increased thermal-oxidative stability, resistance to cracking and deformation, and maintain their performance properties during long-term use under conditions of exposure to sunlight, temperature, and atmospheric factors. A number of technical solutions are known that describe compositions based on polyolefins, including polyethylene, intended for the production of cross-linked materials with increased resistance to heat and light exposure, used in the production of products used outdoors, including films, coatings, shells and insulating materials. Russian Patent No. 2195468 discloses a UV-resistant plastic film or coating used to protect plants from adverse climatic conditions. The material contains a silane-crosslinked polyolefin (including low- and/or high-density polyethylene), a hindered amine-based UV stabilizer (HALS), and a UV absorber such as benzophenone or benzotriazole. Crosslinking is achieved through silane groups introduced by copolymerization and subsequent heat-moisture treatment. A disadvantage of this solution is that the material is designed for silane (moisture) crosslinking, not photocrosslinking under UV irradiation, and is not intended for the production of pipes and other thick-walled products requiring deep and uniform crosslinking across the wall thickness. In addition, the composition does not contain a specialized photochemical initiating complex, glycidyl functional copolymers and organosiloxane coagents that ensure the formation of a three-dimensional network structure in the polyethylene mass. U.S. Patent No. 7,923,121 discloses a photocrosslinkable polyolefin composition comprising a polyolefin (including polyethylene and its copolymers), a source of UV-crosslinkable functionality (e.g., epoxy-containing acrylate or methacrylate moieties), a cationic photoinitiator, and additional radical initiators and stabilizing additives. Crosslinking is achieved by exposure to UV radiation in the 200–500 nm range. The composition is primarily intended for the production of coatings and thin-walled insulating materials that can be crosslinked online during extrusion or molding. The disadvantages of this solution for the task at hand include: reliance on a cationic crosslinking mechanism, insufficient initiation depth in thick-walled products, the absence of a glycidyl-functional organosiloxane coupling agent, the lack of a specialized stabilization system including a hydroxyphenyltriazine-type UV absorber and a HALS stabilizer, and the absence of a three-component antioxidant system (phenolic, phosphite, and thioether antioxidants) in optimal ratios. Furthermore, this composition is not intended for the production of pipes and containers that have high demands on durability and resistance to atmospheric aging. Chinese Patent No. 106632866 describes a material for wire and cable based on ultraviolet cross-linked polyethylene. The composition contains, in parts by weight: polyethylene - 100; free-radical photoinitiator - 0.1-3.0; multifunctional cross-linking agent - 0.1-3.0; cross-linking accelerator - 0.1-2.0; transparent agent - 0.1-2.0; complex antioxidant - 0.1-2.0. UV irradiation ensures the formation of cross-linked cable insulation with improved electrical and heat-resistant properties. Disadvantages with regard to pipes include the absence of glycidyl methacrylate copolymer in the matrix, the absence of a glycidyl-functional organosiloxane coagent, which increases the degree of cross-linking, and the absence of a modern light stabilization system (hydroxyphenyltriazine + HALS). The composition is intended for thin-walled cable sheaths and is not suitable for thick-walled pipes, where significantly higher resistance to UV aging and uniform cross-linking across the thickness are required. Chinese Patent No. 109081976 discloses a polyethylene-based cable insulation material cross-linked by UV LED radiation. It comprises polyethylene, a photoinitiator, a