JP-2026514243-A - Stabilizer for polymer foams based on the regeneration of polydimethylsiloxane

JP2026514243AJP 2026514243 AJP2026514243 AJP 2026514243AJP-2026514243-A

Abstract

Inventors

トーマスローゼン
ミヒャエルフェレンツ
マティアスローベアト
カーステンシラー

Assignees

エボニックオペレーションズゲーエムベーハー

Dates

Publication Date: 20260507
Application Date: 20240425
Priority Date: 20230503

Claims (14)

A method for producing polyether polydimethylsiloxane, (a) A recycled polydimethylsiloxane-containing composition, including recycled linear polydimethylsiloxane, is subjected to an equilibrium reaction with at least one poly(methylhydrogen)siloxane in the presence of at least one equilibrium catalyst to form a poly(methylhydrogen)-polydimethylsiloxane copolymer, (b) The poly(methylhydrogen)-polydimethylsiloxane copolymer obtained in step (a) is subjected to a hydrosilylation reaction with at least one polyether containing at least one carbon-carbon double bond that is reactive to the Si-H bond, preferably in the presence of at least one hydrosilylation catalyst, to obtain a polyether polydimethylsiloxane. The recycled linear polydimethylsiloxane is obtained from the recycling of at least one linear polydimethylsiloxane or its copolymer, and the recycling of at least one linear polydimethylsiloxane or its copolymer is (c) A polydimethylsiloxane-containing composition comprising at least one linear polydimethylsiloxane or a copolymer thereof is subjected to catalytic depolymerization in the presence of at least one depolymerization catalyst to form at least one cyclic polydimethylsiloxane in the depolymerization reaction mixture, (d) Distilling the depolymerization reaction mixture to obtain a cyclic polydimethylsiloxane-containing composition comprising at least one cyclic polydimethylsiloxane, (e) Depending on the circumstances, the cyclic polydimethylsiloxane-containing composition may be subjected to fractional distillation and purification. (f) A cyclic polydimethylsiloxane-containing composition comprising at least one cyclic polydimethylsiloxane is subjected to a polymerization reaction in the presence of a polymerization catalyst to obtain recycled linear polydimethylsiloxane in the recycled polydimethylsiloxane-containing composition, (g) A method comprising, if applicable, purifying the recycled polydimethylsiloxane-containing composition.
The method according to claim 1, wherein the recycled linear polydimethylsiloxane has a viscosity of 25 to 2500 mPa·s, preferably 50 to 2000 mPa·s, more preferably 100 to 1500 mPa·s, and most preferably 150 to 1000 mPa·s at 25°C, as measured according to DIN 53019-1:2008-09.
The recycled polydimethylsiloxane-containing composition contains, based on the total moles of M, D, T, and Q units of the recycled polydimethylsiloxane-containing composition, up to 7.50 mol% of M units, preferably up to 4 mol% of M units, or more preferably up to 2.50 mol% of M units, ... up to 1% The sum of T and Q units of the recycled polydimethylsiloxane-containing composition is at most 0.75 mol%, preferably at most 0.5 mol%, or more preferably at most 0.25 mol%, based on the total moles of M, D, T, and Q units of the recycled polydimethylsiloxane-containing composition. The method according to any one of claims 1 and 2.
The recycled polydimethylsiloxane-containing composition is - Based on the total weight of the recycled polydimethylsiloxane-containing composition, the method comprising up to 0.05% (by weight), preferably up to 100 ppm, more preferably up to 40 ppm (by weight), most preferably up to 10 ppm of water, as measured according to DIN 51777:2020-04; and/or - Based on the total moles of silicon atoms in the recycled polydimethylsiloxane-containing composition, the method comprising up to 0.5 mol%, preferably up to 0.2 mol%, more preferably up to 0.1 mol% of vinyl-substituted silicon atoms, as determined by Si-NMR spectroscopy; and /or - Based on the total moles of silicon atoms in the recycled polydimethylsiloxane-containing composition, the method comprising up to 0.2 mol%, preferably up to 0.1 mol%, more preferably up to 0.05 mol% of hydroxyl-substituted silicon atoms, as determined by Si-NMR spectroscopy.
The method according to any one of claims 1 to 4, wherein the recycled linear polydimethylsiloxane is obtained from the recycling of at least one linear polydimethylsiloxane or its copolymer.
The method according to claim 5, wherein the at least one linear polydimethylsiloxane or its copolymer corresponds to or is derived from waste polydimethylsiloxane polymer or copolymer material, wide-spec polydimethylsiloxane polymer or copolymer material, used polydimethylsiloxane polymer or copolymer material, expired polydimethylsiloxane polymer or copolymer material, surplus polydimethylsiloxane polymer or copolymer material, or any mixture or combination thereof.
The at least one linear polydimethylsiloxane or its copolymer is contained in the polydimethylsiloxane-containing composition, and the polydimethylsiloxane-containing composition is - comprising at least 50% (by weight), preferably at least 70% (by weight), or more preferably at least 90% (by weight), of at least one linear polydimethylsiloxane or its copolymer, based on the total weight of the polydimethylsiloxane-containing composition; and/or - having a silicon content of 19% to 38% (by weight), preferably 26% to 38% (by weight), more preferably 34% to 38% (by weight), based on the total weight of the polydimethylsiloxane-containing composition; and/or - comprising less than 50% (by weight), preferably less than 25% (by weight), or more preferably less than 5% (by weight), of a filler, based on the total weight of the polydimethylsiloxane-containing composition, according to any one of claims 5 and 6.
The aforementioned poly(methylhydrogen)-polydimethylsiloxane copolymer Density of 0.95–0.98 g/mL, preferably 0.96–0.98 g/mL, or more preferably 0.97–0.98 g/mL, at 25°C, as measured according to DIN 51757:2011-01; The method according to any one of claims 1 to 7, wherein the viscosity is 2 to 2000 mPa·s, preferably 3 to 1000 mPa·s, or more preferably 10 to 500 mPa·s, at 25°C, as measured according to DIN 53019-1:2008-09; and/or the SiH value is 0.2 to 10 mol/kg, preferably 0.4 to 8 mol/kg, or more preferably 0.6 to 6 mol/kg, as measured by gas volumetric spectroscopy.
A composition for preparing a polymer foam comprising at least one monomer species and one or more polyether polydimethylsiloxanes obtained by the method described in any one of claims 1 to 8, wherein the polymer foam is preferably a polyurethane foam, a phenolic resin foam, or a polyvinyl chloride foam, and more preferably a polyurethane foam.
A method for preparing a polymer foam, comprising reacting one or more monomer species in the presence of one or more polyether polydimethylsiloxanes obtained by the method described in any one of claims 1 to 8 to obtain a polymer foam.
An article comprising a polymer foam obtained by the method described in claim 10, or as a reaction product of the composition described in claim 9.
The use of recycled linear polydimethylsiloxane for the production of polyether polydimethylsiloxane, wherein the recycled linear polydimethylsiloxane is obtained from the recycling of at least one linear polydimethylsiloxane or its copolymer, and the recycling of at least one linear polydimethylsiloxane or its copolymer is (c) A polydimethylsiloxane-containing composition comprising at least one linear polydimethylsiloxane or a copolymer thereof is subjected to catalytic depolymerization in the presence of at least one depolymerization catalyst to form at least one cyclic polydimethylsiloxane in the depolymerization reaction mixture, (d) Distilling the depolymerization reaction mixture to obtain a cyclic polydimethylsiloxane-containing composition comprising at least one cyclic polydimethylsiloxane, (e) Depending on the circumstances, the cyclic polydimethylsiloxane-containing composition may be subjected to fractional distillation and purification. (f) Subjecting a cyclic polydimethylsiloxane-containing composition containing at least one cyclic polydimethylsiloxane to a polymerization reaction in the presence of a polymerization catalyst to obtain recycled linear polydimethylsiloxane in the recycled polydimethylsiloxane-containing composition, (g) Use, which may include purifying the recycled polydimethylsiloxane-containing composition.
The use according to claim 12, wherein the recycled linear polydimethylsiloxane has a carbon footprint of less than 4 kg CO2 equivalents/kg, or preferably less than 2 kg CO2 equivalents/kg, as determined in accordance with DIN EN ISO standard 14067:2018.
Use of at least one polyether polydimethylsiloxane obtained by the method described in any one of claims 1 to 8 as an additive in a method for producing a polymer foam or a composition for preparing a polymer foam, wherein the polymer foam is preferably a polyurethane foam, a phenolic resin foam, or a polyvinyl chloride foam, and more preferably a polyurethane foam.

Description

This invention relates to polyether polydimethylsiloxane, which can be used as a stabilizer for polymer foams such as polyurethane foams. It is known that polyether polydimethylsiloxane can be produced based on compounds from recycling processes. Therefore, a method for producing polyether polydimethylsiloxane based on recycled linear polydimethylsiloxane is provided. This invention also relates to methods and compositions for preparing polymer foams utilizing polyether polydimethylsiloxane, as well as articles produced therefrom. Furthermore, this invention relates to the use of recycled polydimethylsiloxane-containing compositions and the use of polyether polydimethylsiloxane as a foam stabilizer. Technical Background: Foam stabilizers are typically used to ensure the formation of stable foams. These compounds ensure that gases produced during the reaction do not leak from the reaction mixture and that the resulting foam remains stable until the reaction is complete, preventing collapse. Typical polymer foams are polyurethane foams, phenolic resin foams, or polyvinyl chloride foams. Frequently used foam stabilizers are selected from polyether polydimethylsiloxanes. Linear polydimethylsiloxanes and cyclic polydimethylsiloxanes such as octamethylcyclotetrasiloxane can be used as starting materials for the production of polyether polydimethylsiloxanes. High-purity cyclic polydimethylsiloxanes are typically obtained from chlorosilanes in the Mueller-Rochow process (hereinafter abbreviated as MR or MR process), followed by hydrolysis. The Mueller-Rochow process is the most common process for preparing organosilicon compounds on an industrial scale directly from natural silicon sources such as sand. In the Mueller-Rochow process, alkyl chlorides react with elemental silicon in a fluidized bed reactor. Unfortunately, the Mueller-Rochow process requires a wasteful amount of energy. Therefore, it is desirable to reduce the carbon footprint of the manufacturing process and the polyether polydimethylsiloxane foam stabilizers thus produced, and to provide alternative methods for their preparation. On the other hand, the accumulation of large amounts of plastic waste is one of the global challenges currently facing the world. Indeed, the serious environmental risks of landfills or the incineration of plastic waste are a growing global concern. Under these conditions, the recycling of polymers such as polydimethylsiloxane (also abbreviated herein as PDMS) is essential for the polymer industry's transition to carbon neutrality. Consequently, polydimethylsiloxane is widely used in industry, for example, in sealants, adhesives, lubricants, cookware, and equipment for medical applications, thermal insulation, and electrical insulation. Various recycling methods for polydimethylsiloxanes are known. For example, European Patent Application Publication No. 0009202 discloses that waste materials containing polyorganylsiloxanes can be recycled by catalytic depolymerization. For this purpose, a composition of a linear organopolysiloxane consisting of at least 50 mol% dimethylsiloxane units and aqueous sulfuric acid as a catalyst to promote the rearrangement of siloxane bonds is heated to obtain a cyclic dimethylpolysiloxane-containing composition. Furthermore, U.S. Patent No. 5,110,972 relates to the recycling of waste silicone by dissolving the silicone in a suitable solvent and converting it to a cyclic siloxane by applying a two-step acid/base catalytic cracking process. Thus, the silicone waste consists of high molecular weight liquid or elastomer materials typically formed by silicone polymers having short alkyl groups, particularly methyl groups. The cyclic siloxane-containing composition is ultimately obtained in high yield by distillation. Canadian Patent Application Publication No. 2737235 discloses a method for preparing equilibrium products of organosiloxanes useful as stabilizers for flexible polyurethane foams. Specifically, the document discloses a first step of producing a hydrogen polysiloxane, comprising reacting decamethylcyclopentasiloxane (D5), poly(methyl)hydrogensiloxane, and hexamethyldisiloxane (HMDS) using a pre-dried ion-exchange resin. The resulting polyhydrogendimethylsiloxane is then reacted with a polyether of the central formula CH₂=CH-CH₂O-(C₂H₄O)₅-(C₃H₆O ) ₂CH₃ having a platinum metal complex to form a blocked polysiloxane-polyoxyalkylene, which is used as a stabilizer for flexible polyurethane foams. U.S. Patent Application Publication No. 2006/0241270 discloses a method for preparing equilibrium products of organohydrogensiloxanes. More specifically, the document discloses a first step of mixing a mixture of decaethylcyclopentasiloxane (D5), poly(methyl)hydrogensiloxane PTF1, and hexamethyldisiloxane HMDS with a pre-dried ion-exchange resin, followed by equilibration to obtain a hydrogensiloxane. In the next step, the hydrogensiloxane is further treated with polyethers of various average formul