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US-12617891-B2 - Flexible foams comprising additives for improving hardness

US12617891B2US 12617891 B2US12617891 B2US 12617891B2US-12617891-B2

Abstract

A polyurethane foam-forming composition comprising a polyether functional silicone additive with an active hydrogen atom. The addition of the polyether functional silicone additive to a foam-forming composition for a flexible foam increases the hardness of the resulting foam without adversely affecting other properties of the foam.

Inventors

  • Lorenzo Fiore
  • Lijun Feng
  • Marcel Hartmann
  • Wen Huang
  • Antonie-Gabriel Kiss
  • Alberto Giovanni Mellé

Assignees

  • MOMENTIVE PERFORMANCE MATERIALS INC.

Dates

Publication Date
20260505
Application Date
20210728

Claims (15)

  1. 1 . A flexible polyurethane foam-forming composition comprising: (a) a polyol; (b) a polyisocyanate comprising toluene diisocyanate, the polyisocyanate having an isocyanate index of from about 70 to about 120; (c) a catalyst selected from an organotin catalyst; (d) a surfactant other than a polyether functional silicone (e); and (e) a polyether functional silicone of the formula: M*D x D″ y M* where: M* is R a (CH 3 ) 3-a SiO 1/2 D is (CH 3 ) 2 SiO 2/2 D″ is (CH 3 )(R)SiO 2/2 x is 1-100; y is 1-20 a is 0 or 1; R is polyether substituent C n H 2n O(C 2 H 4 O) b (C 3 H 6 O) c R 1 derived from a single type of polyether substituent, where R 1 is —H, —R 3 N(H)R 2 , or —R 3 SH, R 2 is H or a C1-C10 alkyl, R 3 is C1-C10 alkylene; n is 3 to 4; b is a number such that the ethylene oxide residues constitute from about 30% to about 100% by weight of the alkylene oxide residues of the polyether substituent R; c is a number such that the propylene oxide residues constitute from about 0% to about 70% by weight of the alkylene oxide residues of the polyether substituent R; and the substituent R has a number average molecular weight of from about 200 Dalton to about 5000 Dalton, with the proviso that the flexible polyurethane foam-forming composition is free of a physical blowing agent except that the composition may optionally comprise carbon dioxide or methylene chloride, and wherein a foam produced from the composition is a flexible polyurethane foam.
  2. 2 . The flexible polyurethane foam-forming composition of claim 1 , wherein b in polyether functional silicone (e) is such that the ethylene oxide residues constitute from about 35% to about 100% by weight of the alkylene oxide residues of the polyether substituent R.
  3. 3 . The flexible polyurethane foam-forming composition of claim 1 , wherein b in polyether functional silicone (e) is such that the ethylene oxide residues constitute from about 40% to about 100% by weight of the alkylene oxide residues of the polyether substituent R.
  4. 4 . The flexible polyurethane foam-forming composition of claim 1 , wherein the polyether substituent R of the polyether functional silicone (e) has an ethylene oxide residue content of from about 70% to about 100% by weight.
  5. 5 . The flexible polyurethane foam-forming composition of claim 1 , wherein b of the polyether functional silicone (e) is such that the ethylene oxide residues constitute from about 75% to about 95% by weight of the alkylene oxide residues of the polyether substituent R.
  6. 6 . The flexible polyurethane foam-forming composition of claim 1 , wherein R 1 in the polyether functional silicone (e) is —H.
  7. 7 . The flexible polyurethane foam-forming composition of claim 1 , wherein the polyether substituent R of the polyether functional silicone (e) is a polyether substituent having a number average molecular weight of from about 400 Dalton to about 4000 Dalton.
  8. 8 . The flexible polyurethane foam-forming composition of claim 1 , wherein R in the polyether functional silicone (e) has a number average molecular weight of from about 500 Dalton to about 1500 Dalton.
  9. 9 . The flexible polyurethane foam-forming composition of claim 1 , wherein y in the polyether functional silicone (e) is 2-20.
  10. 10 . The flexible polyurethane foam-forming composition of claim 1 , wherein y in polyether functional silicone (e) is 1-10.
  11. 11 . The flexible polyurethane foam-forming composition of claim 1 , wherein the polyether functional silicone (e) is present in an amount of from about 0.1 to about 10 parts by weight based on the total weight of the flexible polyurethane foam-forming composition.
  12. 12 . A flexible polyurethane foam formed from the flexible polyurethane foam-forming composition of claim 1 .
  13. 13 . The flexible polyurethane foam of claim 12 , wherein the flexible polyurethane foam has a hardness that is greater than the hardness of a foam formed in the absence of the polyether functional silicone (e).
  14. 14 . The flexible polyurethane foam-forming composition of claim 1 comprising water in an amount of about 0.5 parts by weight to about 5 parts by weight based on the weight of the polyurethane foam-forming composition.
  15. 15 . The flexible polyurethane foam-forming composition of claim 1 comprising a blowing agent selected from methylene chloride or carbon dioxide.

Description

FIELD The present invention relates to polyurethane foam-forming compositions containing a silicone additive that improves the hardness of the resulting foams, polyurethane foams formed from said polyurethane foam-forming compositions and processes for making said polyurethane foams. The present invention provides for a flexible polyurethane foam composition and foams made therefrom comprising a polyether functional siloxane where the polyether group contains a reactive hydrogen. BACKGROUND Polyurethane foams are extensively used in a variety of industrial and consumer applications. The production of polyurethane foams is well known to those skilled in the art. Polyurethanes are produced from the reaction of —NCO isocyanate groups present in isocyanates with —OH hydroxyl groups present in polyols. The polyurethane foam production, the reaction of isocyanates with polyols, is carried out in the presence of several additives: surfactants, catalysts, cross-linking agents, flame retardants, water, blowing agents, and other additives. Flexible polyurethane foams, a subcategory of the polyurethane foams, are generally soft, less dense, pliable, and subject to structural rebound subsequent to loading. Due to their high cushioning property, flexible polyurethane foams are widely used for vehicle cushion materials, furniture mats, beddings, miscellaneous goods, and the like. The flexible polyurethane foams are generally manufactured by causing reaction of organic polyisocyanate with two or more compounds containing active hydrogen under existence of a catalyst, a surfactant, and other additives. As the active hydrogen containing compound, there are used polyols, polymer polyols obtained by radical polymerization of acrylonitrile and styrene in a polyol, primary and secondary polyamines, water, and the like. One issue with flexible polyurethane foams is that the hardness of the foam generally cannot be increased without special additives (e.g., fillers or certain types of polyols), and/or decreasing the foam's porosity. The use of fillers is widely employed in the production of flexible foam. Fillers suitable for increasing the hardness are generally categorized into inorganic and organic fillers. Examples of inorganic fillers include, for example, calcium carbonate, barium sulphate, melamine, and the like. Examples of organic fillers (plastic particles) include, for example, copolymer polyols, modified copolymer polyols, modified isocyanate prepolymers, and the like. Inorganic fillers increase hardness while they degrade other physical properties, such as tensile strength, elongation, tear strength, and compression sets significantly. Organic fillers (plastic type) are normally connected into the foam matrix and have uniform macro-distribution. Organic fillers, therefore, tend to provide better performance compared with inorganic fillers. The use of inorganic and/or organic fillers significantly increase the cost to produce flexible foams, increased the difficulty in the foaming process, and can significantly decrease other physical properties especially at high filler dosage levels that may be required to increase the hardness to a desired level. Decreasing or lowering the porosity of the foam is also a consideration and employed to affect the hardness of flexible foams. There are different methods to reduce porosity including, for example, increasing gelling catalyst dosage, increasing silicone surfactant dosage, increasing isocyanate index, and using cross-linkers. The hardness improvement achieved by these methods, however, is not always straight forward or easily controlled, and the impact on the hardness is not always predictable or controllable. While it brings potential side-effects on other physical performance, the hardness reduces gradually when porosity increases in the foam. SUMMARY In one aspect, provided is a foam forming composition for forming a flexible polyurethane foam, where the foam composition comprises a silicone additive that is found to improve the hardness in the foam. The silicone additive is a siloxane comprising a reactive polyether functional group. The use of the silicone additive is found to increase the hardness of the foam without negatively affecting other properties in the foam. Additionally, these polyether functional siloxanes enable improved foam hardness in the flexible foam formulations with the potential elimination of copolymer polyols, or other additives. In one aspect, provided is a polyurethane foam-forming composition comprising: (a) a polyol; (b) a polyisocyanate; (c) a catalyst; (d) a surfactant; and (e) a polyether functional silicone of the formula: M*DxD″yM* where:M* is Ra(CH3)3-aSiO1/2 D is (CH3)2SiO2/2 D″ is (CH3)(R)SiO2/2 x is 0-100;y is 0-20a is 0 or 1 with the proviso that y is greater than 0 if a is 0; when a is 0, M* becomes M: (CH3)3SiO1/2.R is polyether substituent CnH2nO(C2H4O)b(C3H6O)cR1 where R1 is —H, —R3N(H)R2, or —R3SH, R2 is H or a C1-C10 alkyl,