Polyurethane composition and viscoelastic polyurethane foam with few surface defects prepared using the same

Abstract

A polyurethane composition is provided that includes (A) an isocyanate compound and (B) a polyol blend of three polyether polyols with specially designed formulations and OH functionality, and viscoelastic polyurethane foams prepared using the polyurethane composition exhibit tailored viscoelastic properties and excellent aesthetic appearance.

Description

[Technical Field]

[0001] The present invention relates to a polyurethane (PU) composition and a polyurethane foam with fewer surface defects prepared using the composition. The polyurethane composition comprises a blend of three polyether polyols specifically designed to substantially inhibit the formation of defects on the surface of the resulting viscoelastic polyurethane foam, thereby producing a viscoelastic polyurethane foam with intended viscoelastic properties and excellent aesthetic appearance. [Background technology]

[0002] Viscoelastic polyurethane (PU) foam is a well-known polyurethane material exhibiting moderate elasticity and a slow recovery rate, and is used in a variety of office, home, and vehicle applications such as pillows, wheelchair seats, and mattresses for its cushioning, energy absorption, sound insulation, and vibration damping functions. Nevertheless, several challenges remain to be overcome. For example, one significant problem is the presence of defects such as bubbles, pinholes, wrinkles, cracks, and fractures both on the outer surface and within the internal volume of the polyurethane foam. All of these defects introduce undesirable, non-uniform local microstructures that can adversely affect the vibration absorption efficiency of the polyurethane foam article. In many applications, viscoelastic polyurethane (PU) foam often has a moderate thickness of a few centimeters or less and is typically formed in a thin-cavity mold. When a reactive mixture consisting of a polyol component and an isocyanate component, including polyols and additives such as catalysts, surfactants, and blowing agents, is grown and expanded in such a thin-walled mold, all reactants generally encounter a non-laminar flow, and the turbulence caused by such a non-laminar flow is considered to be one of the essential causes of the formation or trapping of various defects in the final polyurethane foam. Intensive efforts have been made in the past to solve this problem, but the research results have remained very limited. Therefore, there has been a long-standing need to develop unique technologies that can be used to effectively inhibit the formation and trapping of defects during polyurethane foam production while maintaining the viscoelasticity of the resulting foam product.

[0003] After continuous research, the inventors have, surprisingly, developed a composition containing a unique blend of polyols that can achieve the above objectives. [Overview of the Initiative]

[0004] This disclosure provides a unique polyurethane composition comprising a blend of three specially defined polyols that can inhibit non-laminar flow during the preparation of polyurethane foam, thereby producing foam products having tailored viscoelastic properties and excellent aesthetic appearance, and a polyurethane foam product prepared using the composition.

[0005] In a first aspect of this disclosure, the disclosure relates to a polyurethane composition for preparing a viscoelastic polyurethane foam, (A) at least one isocyanate compound comprising at least two isocyanate groups, (B) (b1) A poly(C2-C6 alkylene oxide) polyol with an ethylene oxide moiety at the end, and a first polyether polyol having an OH functional value of 4 or more. (b2) A poly(C2-C6 alkylene oxide) polyol with a propylene oxide moiety at the end, a second polyether polyol having an OH functional value of 2-6, and (b3) A third polyether polyol that is a random copolymer of two or more (C2-C6) alkylene oxides and has an OH functional value of 2 to 6. A polyol blend containing, A polyurethane composition containing the following is provided.

[0006] In a second aspect of this disclosure, the disclosure provides a viscoelastic polyurethane foam product prepared by using the above-described polyurethane composition.

[0007] Please understand that both the general description above and the detailed description below are illustrative and descriptive, and do not limit the claimed invention. [Brief explanation of the drawing]

[0008] [Figure 1] This is a photograph of a polyurethane foam prepared according to an embodiment of the present invention. [Figure 2] This is a photograph of polyurethane foam prepared by the comparative example of this disclosure. [Modes for carrying out the invention]

[0009] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this invention pertains. Furthermore, all publications, patent applications, patents, and other references referenced herein are incorporated by reference.

[0010] In this disclosure, “and / or” means “and, or alternatively.” All ranges include the endpoint unless otherwise indicated. Unless otherwise stated, all percentages and ratios are calculated on a weight basis, and all molecular weights are weight-average molecular weight (Mw) (g / mol).

[0011] While not limited to any particular theory, the technical breakthrough of this disclosure lies primarily in specially designed polyol blends used as isocyanate-reactive compounds in compositions. In particular, viscoelastic polyurethane foams are typically prepared by combining polyol components, including polyols (plural) and additives such as catalysts, surfactants, and blowing agents, with isocyanate components, and reacting and expanding the reaction mixture in a mold, such as a thin-walled mold. The non-laminar and turbulent flow generated during the reaction is presumed to be the essential cause of the formation or trapping of various defects, such as bubbles, in the final polyurethane foam. Surprisingly, it has been found that a specially defined blend of three polyols can effectively inhibit the trapping of bubbles and the formation of defects in the final foam.

[0012] According to embodiments of the present disclosure, the polyurethane composition of the present disclosure comprises a polyol blend comprising: (b1) a first polyether polyol which is a poly(C2-C6 alkylene oxide) polyol with ethylene oxide moieties end-protected and has an OH functional value of 4 or more; (b2) a second polyether polyol which is a poly(C2-C6 alkylene oxide) polyol which is a poly(C2-C6 alkylene oxide) polyol with propylene oxide moieties end-protected and has an OH functional value of 2 to 6; and (b3) a third polyether polyol which is a random copolymer of two or more (C2-C6) alkylene oxides and has an OH functional value of 2 to 6.

[0013] According to one embodiment of the present disclosure, the C2-C6 alkylene oxide of the first polyether polyol can be selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, pentylene oxide, and hexylene oxide. According to an exemplary embodiment of the present disclosure, the C2-C6 alkylene oxide of the first polyether polyol may also be propylene oxide, i.e., the first polyether polyol may be a poly(propylene oxide) polyol with an ethylene oxide moiety at the end. According to another embodiment of the present disclosure, the first polyether polyol has an ethylene oxide content based on the total weight of the first polyether polyol, which is within a numerical range obtained by combining any two of the following values: 14% by weight, 15% by weight, 16% by weight, 17% by weight, 18% by weight, 19% by weight, 20% by weight, 21% by weight, 22% by weight, 23% by weight, 24% by weight, 25% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight, 31% by weight, 32% by weight, 33% by weight, 34% by weight, 35% by weight, 36% by weight, 37% by weight, 38% by weight, 39% by weight, 40% by weight, 41% by weight, 42% by weight, 43% by weight, 44% by weight, and 45% by weight. According to another embodiment of the present disclosure, the first polyether polyol has a hydroxyl functional value within a numerical range obtained by combining any two of the following values: 4.0, 4.2, 4.4, 4.5, 4.7, 4.8, 5.0, 5.2, 5.4, 5.5, 5.7, 5.8, 6.0, 6.2, 6.4, 6.5, 6.7, 6.8, 7.0, 7.2, 7.4, 7.5, 5.7, 7.8, 8.0, 8.2, 8.4, 8.5, 8.7, 8.8, 9.0, 9.2, 9.4, 9.5, 9.6, 9.7, 9.8, and 10.0.According to an embodiment of the present disclosure, the first polyether polyol has a molecular weight within a numerical range obtained by combining any two of 3,000 to 10,000, or 4,000 to 9,000, or 5,000 to 8,000, or 6,000 to 7,000, for example, the following values: 3,000, 3,200, 3,500, 3,800, 4,000, 4,200, 4,500, 4,800, 5,000, 5,200, 5,500, 5,800, 6,000, 6,200, 6,500, 6,800, 7,000, 7,200, 7,500, 7,800, 8,000, 8,200, 8,500, 8,800, 9,000, 9,200, 9,500, 9,800, and 10,000.

[0014] According to another embodiment of the present disclosure, when the total weight of the polyol blend is 100 parts per hundred of polyol (pphp), the content of the first polyether polyol is within a numerical range obtained by combining any two of 50 to 75 pphp, for example 51 to 72 pphp, or the following values: 50 pphp, 51 pphp, 51.8 pphp, 52 pphp, 53 pphp, 54 pphp, 55 pphp, 56 pphp, 57 pphp, 58 pphp, 59 pphp, 60 pphp, 60.4 pphp, 61 pphp, 62 pphp, 62.5 pphp, 63 pphp, 64 pphp, 65 pphp, 66 pphp, 67 pphp, 68 pphp, 69 pphp, 70 pphp, 71 pphp, 71.1 pphp, 72 pphp, 73 pphp, 73.1 pphp, 74 pphp, and 75 pphp.

[0015] Examples of the first polyether polyol can be commercially purchased from suppliers such as SPECFLEX™ NC 632 and SPECFLEX™ NC 630 available from The Dow Chemical Company.

[0016] According to one embodiment of the present disclosure, the C2-C6 alkylene oxide of the second polyether polyol can be selected from the group consisting of ethylene oxide, propylene oxide, butylene oxide, pentylene oxide, and hexylene oxide. The second polyether polyol can be considered a homopolymerized polypropylene oxide polyol or a fully polypropylene oxide polyol when the C2-C6 alkylene oxide of the second polyether polyol is propylene oxide. According to another embodiment of the present disclosure, the C2-C6 alkylene oxide of the second polyether polyol is a C3-C6 alkylene oxide. According to an exemplary embodiment of the present disclosure, the C2-C6 alkylene oxide of the second polyether polyol may also be propylene oxide, i.e., the second polyether polyol is a poly(propylene oxide) polyol with a propylene oxide moiety end-protected, which can also be considered a homopolymerized or fully polypropylene oxide polyol.According to another embodiment of the present disclosure, the second polyether polyol is up to 100% by weight, or 5% to 100% by weight, based on the total weight of the second polyether polyol, for example, the following values: 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20% %, 21wt%, 22wt%, 23wt%, 24wt%, 25wt%, 26wt%, 27wt%, 28wt%, 29wt%, 30wt%, 31wt%, 32wt%, 33wt%, 34wt%, 35wt Amount%, 36% by weight, 37% by weight, 38% by weight, 39% by weight, 40% by weight, 41% by weight, 42% by weight, 43% by weight, 44% by weight, 45% by weight, 46% by weight, 47% by weight, 48% by weight, 49% by weight, 50 Weight%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 6 5% by weight, 66% by weight, 67% by weight, 68% by weight, 69% by weight, 70% by weight, 71% by weight, 72% by weight, 73% by weight, 74% by weight, 75% by weight, 76% by weight, 77% by weight, 78% by weight, 79% by weight, It has a propylene oxide content within a numerical range obtained by combining any two of the following: 80% by weight, 81% by weight, 82% by weight, 83% by weight, 84% by weight, 85% by weight, 86% by weight, 87% by weight, 88% by weight, 89% by weight, 90% by weight, 91% by weight, 92% by weight, 93% by weight, 94% by weight, 95% by weight, 96% by weight, 97% by weight, 98% by weight, 99% by weight, and 100% by weight.According to another embodiment of the present disclosure, the second polyether polyol is 2.0 to 6.0, or 2.0 to 5.0, or 2.0 to 4.0, or 2.0 to 3.5, or 2.5 to 3.2, or 2.8 to 3.0, for example, the following values: 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3 , 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, and 6.0 have a hydroxyl functional value within a numerical range obtained by combining any two of these. According to a particular embodiment of the present disclosure, the second polyether polyol is a poly(propylene oxide) polyol with a propylene oxide moiety end-protected, i.e., a homopolymer or a complete polypropylene oxide polyol, having an OH functional value of 2 to 6, for example, 3. According to embodiments of this disclosure, the second polyether polyol is 150-2,500, or 500-2,000, or 700-1,000, for example, the following values: 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,050, 1,100, 1,150, 1,200, 1,250, 1,300, 1, It may have a molecular weight within the range obtained by combining any two of the following: 350, 1,400, 1,450, 1,500, 1,550, 1,600, 1,650, 1,700, 1,750, 1,800, 1,850, 1,900, 1,950, 2,000, 2,050, 2,100, 2,150, 2,200, 2,250, 2,300, 2,350, 2,400, 2,450, and 2,500.

[0017] According to another embodiment of the present disclosure, when the total weight of the polyol blend is 100 parts per 100 parts of polyol (pphp), the content of the second polyether polyol is 20 to 35 pphp, such as 21 to 33 pphp, or the following values: 20 pphp, 21 pphp, 21.4 pphp, 22 pphp, 23 pphp, 24 pphp, 25 pphp, 26 pphp, 27 pphp, 28 pphp, 29 pphp, 30 pphp, 31 pphp, 32 pphp, 32.1 pphp, 33 pphp, 34 pphp, and any numerical range obtained by combining any two of 35 pphp.

[0018] Examples of the second polyether polyol include VORANOL™ 270, VORANOL™ 2070, VORANOL™ CP 755, VORANOL™ 450, and VORANOL™ CP 1055 available from The Dow Chemical Company and can be commercially purchased from suppliers.

[0019] According to one embodiment of the present disclosure, the third polyether polyol may be a random copolymer of ethylene oxide and propylene oxide, a random copolymer of ethylene oxide and butylene oxide, a random copolymer of propylene oxide and butylene oxide, or a random copolymer of ethylene oxide, propylene oxide, and butylene oxide. According to another embodiment of the present disclosure, the third polyether polyol is based on the total weight of the third polyether polyol and is in the following proportions: 55% to 90% by weight, or 58% to 85% by weight, or 60% to 80% by weight, or 65% to 76% by weight, or 68% to 75% by weight, or 70% to 72% by weight, for example: 55% by weight, 56% by weight, 57% by weight, 58% by weight, 59% by weight, 60% by weight, 61% by weight, 62% by weight, 63% by weight, 64% by weight, 65% by weight, 66% by weight, 67% by weight, 68% by weight. An ethylene oxide-propylene oxide random copolymer having an ethylene oxide content within a numerical range obtained by combining any two of the following: 69% by weight, 70% by weight, 71% by weight, 72% by weight, 73% by weight, 74% by weight, 75% by weight, 76% by weight, 77% by weight, 78% by weight, 79% by weight, 80% by weight, 81% by weight, 82% by weight, 83% by weight, 84% by weight, 85% by weight, 86% by weight, 87% by weight, 88% by weight, 89% by weight, and 90% by weight, with the remaining content being propylene oxide.

[0020] According to another embodiment of this disclosure, the third polyether polyol is 2.0 to 6.0, or 2.0 to 5.5, or 2.0 to 5.0, or 2.0 to 4.5, or 2.0 to 4.0, or 2.0 to 3.5, or 2.5 to 3.2, or 2.8 to 3.0, for example, the following values: 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, It has a hydroxyl functional value within the range obtained by combining any two of the following values: 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, and 6.0. According to embodiments of this disclosure, the third polyether polyol is 1,550-10,000, or 2,000-9,000, or 3,000-8,000, or 4,000-7,000, 5,000-6,000, for example, the following values: 1,550, 1,600, 1,700, 1,800, 2,000, 2,200, 2,500, 2,800, 3,000, 3,200, 3,500, 3,800, 4,000, 4 It has a molecular weight within the range obtained by combining any two of the following: 200, 4,500, 4,800, 5,000, 5,200, 5,500, 5,800, 6,000, 6,200, 6,500, 6,800, 7,000, 7,200, 7,500, 7,800, 8,000, 8,200, 8,500, 8,800, 9,000, 9,200, 9,500, 9,800, and 10,000.

[0021] According to another embodiment of the present disclosure, when the total weight of the polyol blend is 100 parts (pphp) per 100 parts of polyol, the content of the third polyether polyol is within a numerical range obtained by combining any two of the following values: 5 to 20 pphp, or 7 to 18 pphp, or 10 to 15 pphp, for example: 5 pphp, 6 pphp, 7 pphp, 8 pphp, 9 pphp, 10 pphp, 11 pphp, 12 pphp, 13 pphp, 14 pphp, 15 pphp, 16 pphp, 17 pphp, 18 pphp, 19 pphp, and 20 pphp.

[0022] Examples of a third type of polyether polyol can be commercially purchased from suppliers, such as Dow VORANOL® 1447 and VORANOL® CP 1421, available from Dow Chemical Company.

[0023] The polyol blend content, i.e., the total content of the first, second, and third polyether polyols, may vary based on the actual requirements of the viscoelastic polyurethane foam. For example, in one exemplary embodiment, the polyol blend content may be within a numerical range obtained by combining any two of the following values ​​based on the total weight of the polyurethane composition: 50% to 80% by weight, or 52% to 70% by weight, or 55% to 65% by weight, or 58% to 60% by weight, for example: 50% by weight, 51% by weight, 52% by weight, 53% by weight, 54% by weight, 55% by weight, 56% by weight, 57% by weight, 58% by weight, 59% by weight, 60% by weight, 61% by weight, 62% by weight, 63% by weight, 64% by weight, 65% by weight, 66% by weight, 67% by weight, 68% by weight, 69% by weight, 70% by weight, 71% by weight, 72% by weight, 73% by weight, 74% by weight, 75% by weight, 76% by weight, 77% by weight, 78% by weight, 79% by weight, and 80% by weight.

[0024] According to one embodiment of the present disclosure, the polyurethane composition of the present disclosure does not contain any additional isocyanate-reactive compounds other than the first to third polyether polyols. As used herein, the term “additional isocyanate-reactive compounds” refers to compounds that have the sole function of reacting with isocyanates to form the polyurethane main chain, and therefore does not include additives commonly used for various functions during the manufacture of polyurethane foams, such as chain extenders, crosslinkers, silicone surfactants, blowing agents, or catalysts.

[0025] According to another embodiment of the present disclosure, one or more additional isocyanate-reactive compounds other than the first to third polyether polyols may be used in combination with the polyol blend of the first to third polyether polyols, the weight ratio of the additional isocyanate-reactive compound to the polyol blend of the first to third polyether polyols may be 0.1:100 to 50:100, or 0.5:100 to 45:100, or 1:100 to 40:100, or 2:100 to 35:100, or 3:100 to 30:100, or 4:100 to 25:100, or 5:100 to 20:100, or 6:100 to 15:100, or 7:100 to 12:100, or 8:100 to 10:100. If present, additional isocyanate-reactive compounds are C2-C2 compounds containing at least two hydroxyl groups. 16 Aliphatic polyhydric alcohols, C6-C2 containing at least two hydroxyl groups 16 Alicyclic polyhydric alcohols, C6-C2 containing at least two hydroxyl groups 16 Aromatic polyhydric alcohols, C7-C2 containing at least two hydroxyl groups 15The polyols can be selected from the group consisting of aromatic aliphatic polyhydric alcohols, polyester polyols having a molecular weight of 500 to 12,000, polycarbonate polyols having a molecular weight of 200 to 8,000, polyether polyols having a molecular weight of 200 to 8,000 that are different from the first to third polyether polyols, core-shell polymer polyols having a core phase and a shell phase based on a polyol, or any combination thereof. The shell phase of the core-shell polymer polyol may contain one or more of the additional isocyanate-reactive compounds described above. The core phase of the core-shell polymer polyol may be microsized and may contain any polymer compatible with the shell phase. For example, the core phase may contain polystyrene, polyacrylonitrile, polyester, polyolefin, or polyether.

[0026] In various embodiments, isocyanate compounds containing at least two isocyanate groups are also known as polyisocyanate compounds and refer to aliphatic, alicyclic, aromatic, aromaticaliphatic, or heteroaryl compounds having at least two isocyanate groups. Isocyanate compounds may have an average functional value of at least about 2.0, for example, about 2 to 10, or about 2 to about 8, or about 2 to about 6, or about 2 to about 5, or about 2 to about 4, or about 2 to about 3. Exemplary isocyanate compounds include C2-C2 compounds containing at least two isocyanate groups. 12 Aliphatic isocyanate compounds, C6-C6 containing at least two isocyanate groups 15 Alicyclic isocyanate compounds, C6-C6 compounds containing at least two isocyanate groups 15 Aromatic isocyanate compounds, C7-C containing at least two isocyanate groups 15The isocyanate compounds may be selected from the group consisting of aromatic aliphatic isocyanate compounds and any combination thereof. In another embodiment, the isocyanate compounds may include, in particular, m-phenylenediisocyanate, 2,4-toluenediisocyanate, 2,6-toluenediisocyanate (TDI), various isomers of diphenylmethanediisocyanate (MDI), methylenebis(cyclohexyl isocyanate) (HMDI), hexamethylene-1,6-diisocyanate (HDI), tetramethylene-1,4-diisocyanate, cyclohexane-1,4-diisocyanate, hexahydrotoluenediisocyanate, hydrogenated MDI, naphthylene-1,5-diisocyanate, isophorone diisocyanate (IPDI), or mixtures thereof. Examples of the isocyanate compounds described above can be commercially purchased from suppliers, such as SPECFLEX® NE138, ISONATE® M125, and ISONATE® OP50, available from Dow Chemical Company. According to another embodiment of this disclosure, the isocyanate compound may be a modified isocyanate compound, i.e., a product obtained by chemical modification of the above isocyanate compound. Exemplary modified isocyanate compounds are polyisocyanates containing esters, urea, biuret, isocyanurate, allophanate, carbodiimide, or uretonimine, such as 4,4'-carbodiimide-modified MDI products. For example, liquid isocyanate compounds containing a carbodiimide group, a uretonimine group, or an isocyanurate ring and having an isocyanate group (NCO) content of 10 to 40 percent by weight, for example, 20 to 35 percent by weight, can be used. Further examples may also include mixtures of at least one of the above-mentioned isocyanate compounds with other components, such as polymer MDI, known as a mixture of about 50% by weight of MDI and the remainder being a higher molecular weight polycyclic species, which can be commercially purchased from suppliers, such as PAPI 27 available from Dow Chemical Company.

[0027] Alternatively or additionally, the isocyanate compound may include an isocyanate prepolymer having an NCO functionality in the range of 2 to 10, such as 2 to 8, or 2 to 6, or 2 to 5, or 2 to 4. The isocyanate prepolymer contains at least two free isocyanate groups, that is, under the condition that the relative amounts of the raw materials for preparing the prepolymer are isocyanate-excess such that a free isocyanate moiety remains in the final prepolymer, the isocyanate prepolymer may include one or more of the above monomeric isocyanate compound(s) and a C2-C 16 aliphatic polyhydric alcohol, a C5-C containing at least two hydroxy groups 16 alicyclic polyhydric alcohol, a C6-C containing at least two hydroxy groups 16 aromatic polyhydric alcohol, a C7-C containing at least two hydroxy groups 15It can be obtained by reacting with one or more isocyanate-reactive compounds selected from the group consisting of aromatic aliphatic polyhydric alcohols, polyester polyols having a molecular weight of 500 to 5,000, polycarbonate polyols having a molecular weight of 200 to 5,000, polyether polyols having a molecular weight of 200 to 8,000, or any combination thereof. The polyether polyol may be the same as or different from any one of the first to third polyether polyols described above. For example, isocyanate-reactive compounds for preparing the isocyanate prepolymer can be selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,4-butenediol, 1,4-butynediol, 1,5-pentanediol, neopentyl glycol, bis(hydroxymethyl)cyclohexane (e.g., 1,4-bis(hydroxymethyl)cyclohexane), 2-methylpropane-1,3-diol, methylpentanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol, polybutylene glycol, bishydroxyethyl-bisphenol A, bishydroxypropyl-bisphenol A, cyclohexanedimethanol, and bishydroxyethylhydroquinone. An example of a polyol for preparing the isocyanate prepolymer is VORANOL® CP 6001, available from Dow Chemical Company. Suitable isocyanate prepolymers may have an NCO group content of 2 to 40 percent by weight, for example, 4 to 30 percent by weight. Examples of such isocyanate prepolymers can be commercially purchased from suppliers, such as SPECFLEX® NE 135, available from Dow Chemical Company.

[0028] The isocyanate compound content may vary based on the actual requirements of the viscoelastic polyurethane foam. In one exemplary embodiment, the isocyanate compound content may be within a numerical range obtained by combining any two of the following values, based on the total weight of the polyurethane composition: 25% to 45% by weight, or 30% to 40% by weight, or 32% to 35% by weight, for example: 25% by weight, 26% by weight, 27% by weight, 28% by weight, 29% by weight, 30% by weight, 31% by weight, 32% by weight, 33% by weight, 34% by weight, 35% by weight, 36% by weight, 37% by weight, 38% by weight, 39% by weight, 40% by weight, 41% by weight, 42% by weight, 43% by weight, 44% by weight, and 45% by weight. According to embodiments of the present disclosure, the amount of the isocyanate compound is appropriately selected such that the isocyanate group is present in an amount stoichiometrically equivalent to or stoichiometrically insufficient to the total molar amount of isocyanate-reactive groups (e.g., hydroxyl groups, amino groups, etc.) contained in the polyol compound and all other additives, such as chain extenders, crosslinkers, modifiers, compatibilizers, solvents, and cosolvents. For example, the molar ratio between isocyanate groups and isocyanate-reactive groups may be 0.6:1 to 1:1, or 0.7:1 to 1:1, or 0.8:1 to 1:1, or 0.9:1 to 1:1, for example, about 1:1.

[0029] In various embodiments of this disclosure, the polyurethane composition comprises one or more additives selected from the group consisting of catalysts, surfactants, chain extenders, crosslinking agents, foaming agents, foaming agents, foam stabilizers, antioxidants, tackifiers, plasticizers, rheology modifiers, UV absorbers, light stabilizers, cocatalysts, fillers, colorants, pigments, solvents, diluents, flame retardants, anti-slip agents, antistatic agents, preservatives, biocides, and any combination thereof. These additives may be delivered and stored as separate components and incorporated into the polyurethane composition shortly before or immediately before combining the isocyanate compound and polyol blend and any other isocyanate-reactive compound(s) present. Alternatively, these additives may be contained in either the isocyanate compound or the polyol blend if they are chemically inert or substantially inert to isocyanate groups or isocyanate-reactive groups.

[0030] A suitable surfactant is a substance that stabilizes the foam formed during the foaming reaction until the foam has sufficiently hardened and become self-supporting. A wide variety of silicone surfactants commonly used to produce polyurethane foams can be used in this disclosure. Examples of such silicone surfactants are commercially available, such as VORASURF® DC 2525 from Dow Chemical Company and Tegostab B8734 LF2 from Evonik Industries AG.

[0031] Surfactants are typically present in an additional content of 5 pphp or less, for example, 0.1–4 pphp, 0.2–3 pphp, 0.3–2 pphp, 0.4–1 pphp, or 0.5–0.8 pphp, when the total weight of the polyol blend is 100 pphp.

[0032] As used herein, the term “additional content” means that the content of the subject in question does not constitute part of the total weight of the polyol blend. For example, a combination of 100 pphp of polyol blend and an additional 0.5 pphp of surfactant or any other ingredient will yield a total weight of 100.5 pphp.

[0033] Furthermore, one or more crosslinking agents may be present in the polyurethane composition of this disclosure. For the purposes of the present invention, “crosslinking agent” means a substance having three or more isocyanate-reactive groups in one molecule and an equivalent per isocyanate-reactive group of less than 300, for example, less than 200. A crosslinking agent typically contains 3 to 8, particularly 3 to 4, hydroxyl (including primary, secondary, and tertiary hydroxyl), primary amine, secondary amine, or tertiary amine groups in one molecule and has an equivalent of 30 to about 200, particularly 50 to 125. According to embodiments of this disclosure, the crosslinking agent may be selected from the group consisting of diethanolamine (DEOA), triethanolamine (TEOA), di(isopropanol)amine, tri(isopropanol)amine, glycerin, trimethylolpropane, pentaerythritol, and any combination thereof, for example, a combination of DEOA and TEOA. The crosslinking agent may be present as a mixture with a polyol blend.

[0034] The chain extender is a chemical substance having two or more isocyanate-reactive groups per molecule, with an equivalent weight of less than 300, for example, less than 200, per isocyanate-reactive group. The isocyanate-reactive group may be a hydroxyl group, a primary aliphatic or aromatic amino group, or a secondary aliphatic or aromatic amino group. Typical chain extenders include monoethylene glycol (MEG), diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripylene glycol, 1,4-butanediol, cyclohexanedimethanol, ethylenediamine, phenylenediamine, bis(3-chloro-4-aminophenyl)methane, dimethylthiotoluenediamine, or diethyltoluenediamine. According to embodiments of this disclosure, the chain extender is a short-chain (C2-C4, etc.) polyol containing only hydroxyl groups as isocyanate-reactive groups, such as monoethylene glycol. According to another embodiment of the present disclosure, the chain extender may be selected from the group consisting of ethylene glycol, propanediol, butanediol, pentanediol, hexanediol, 1,4-cyclohexanedimethanol, and their isomers. The chain extender may exist as a mixture with the polyol blend.

[0035] Chain extenders and crosslinkers are used appropriately in small amounts because increasing the amount of either of these materials increases the hardness of the final foam. Chain extenders are typically present in an additional content of 5 pphp or less, e.g., 0.1–4 pphp, or 0.2–3 pphp, or 0.3–2 pphp, or 0.4–1.5 pphp, or 0.5–1.0 pphp, or 0.6–0.8 pphp, when the total weight of the polyol blend is 100 pphp. Chain extenders may be present in an additional content of 5 pphp or less, e.g., 0.1–4 pphp, or 0.2–3 pphp, or 0.3–2 pphp, or 0.4–1.5 pphp, or 0.5–1.0 pphp, or 0.6–0.8 pphp, when the total weight of the polyol blend is 100 pphp.

[0036] The blowing agent may be of the chemical (exothermic) type, the physical (endothermic) type, or a mixture of at least one of each type. A chemical blowing agent is typically a substance that reacts or decomposes under conditions of a blowing reaction to produce carbon dioxide or carbon monoxide gas. Water and formic acid are examples of suitable chemical blowing agents. Examples of physical blowing agents include carbon dioxide, various low-boiling hydrocarbons, hydrofluorocarbons, hydrofluorochlorocarbons, and ethers. Water, alone or in combination with one or more chemical or physical blowing agents, is one of the typical chemical blowing agents. The blowing agent may be present in an additional content of 10 pphp or less, e.g., 0.5–8 pphp, or 0.8–7 pphp, or 1–6 pphp, or 2–5 pphp, or 3–4 pphp, based on a total weight of 100 pphp of the polyol blend.

[0037] In this application, any catalyst that effectively promotes the reaction between the isocyanate group and the isocyanate-reactive group may be used. For example, the catalyst may be selected from the group consisting of: amine catalysts, e.g., ethylenediamine, propylenediamine, butylenediamine, pentylenediamine, neopentylenediamine, hexylenediamine, heptylenediamine, neoheptylenediamine, N,N-dimethylcyclohexylamine, N,N-bis(3-(dimethylamino)propyl)-N-diisopropanolamine, bis(2-dimethylaminoethyl) ether, methyltriethylenediamine, dimethylaminopropylamine, bis( N,N-dimethyl-3-aminopropyl)amine, bis(2-dimethylaminoethyl) ether, 1,1'-((3-(dimethylamino)propyl)azandiyl)bis(propan-2-ol), 2,4,6-tridimethylaminomethyl)phenol, N,N,N',N'-tetramethylethylenediamine, N,N,N',N'-tetramethylpropylenediamine, N,N,N',N'-tetramethylbutylenediamine, N,N,N',N'-tetramethylpentylenediamine, N,N,N',N'- Tetramethylhexylenediamine, N,N-dimethylbenzylamine, triethylenediamine, pentamethyldiethylenetriamine, diethylenetriamine, N-methylmorpholine, N-ethylmorpholine, 2-methylpropanediamine, N,N'-diethylpiperazine, N,N'-dimethylpiperazine, pyridine, N,N'-dimethylpyridine, quinoline, N,N',N''-tris(dimethylaminopropyl)sym-hexahydrotriazine; glycine salts; trialkylphosphines and dialkyl Tertiary phosphines such as benzylphosphine; chelates of various metals, such as those obtainable from acetylacetone, benzoylacetone, trifluoroacetylacetone, acetate acetate, etc., with metals such as Be, Mg, Zn, Cd, Pd, Ti, Zr, Sn, As, Bi, Cr, Mo, Mn, Fe, Co, and Ni; acidic metal salts of strong acids such as ferric chloride and stannic chloride; salts of organic acids containing various metals such as alkali metals, alkaline earth metals, Al, Sn, Pb, Mn, Co, Ni, and Cu;Organotin compounds such as tin(II) salts of organic carboxylic acids, e.g., tin(II) diacetate, tin(II) dioctanoate, tin(II) diethylhexanoate, and tin(II) dilaurate, and dialkyltin(IV) salts of organic carboxylic acids, e.g., dibutyltin diacetate, dibutyltin dilaurate, dibutyltin maleate, and dioctyltin diacetate; bismuth salts of organic carboxylic acids, e.g., bismuth octanoate; organometallic derivatives of trivalent and pentavalent As, Sb, and Bi, and metal carbonyls of iron and cobalt. Examples of such catalysts are commercially available as JEFFCAT catalysts, such as JEFFCAT ZR-50 from Huntsman Corporation. The catalyst may be present in an additional content of 8 pphp or less, for example, 0.5-7 pphp, 0.8-6 pphp, 1-5 pphp, 2-4 pphp, or 2.1-3 pphp, when the total weight of the polyol blend is 100 pphp.

[0038] The process for preparing polyurethane foam may further involve the use of additional additives such as mold release agents, foam stabilizers, tackifiers, plasticizers, rheology modifiers, UV absorbers, light stabilizers, cocatalysts, fillers, colorants, pigments, solvents, diluents, flame retardants, anti-slip agents, antistatic agents, preservatives, biocides, or any combination thereof.

[0039] For example, a release agent may be applied to the surface of the mold before the casting process to facilitate the release of the cured foam article. The release agent may be applied by spraying / pouring it onto the surface of the mold and then dispersing it with a cloth. Examples include commercially available release agents commonly used in related fields, such as paraffin wax dispersed in low molecular weight hydrocarbons, a specific example being ChemTrend PU 1705 M from ChemTrend.

[0040] The viscoelastic polyurethane foams of this disclosure can be prepared by using conventional techniques such as casting, injection molding, pressure molding, die molding, free-rise box foaming, spin-casting, and spray foaming, and can be manufactured and processed manually or automatically in batch or continuous processes. A typical process for preparing a viscoelastic polyurethane foam includes (i) mixing an isocyanate compound with a polyol blend to form a reactive mixture, and (ii) pouring the reactive mixture into a mold. According to embodiments of this disclosure, one or more substrate layers may be pre-placed in the mold, such as by being placed at the bottom of the mold, so as to adhere to the polyurethane foam during the formation, foaming, and curing of the polyurethane foam, thereby creating an integrated laminated structure including a viscoelastic polyurethane foam layer supported on the substrate layers. Examples of substrates include, for example, metal substrates such as steel plates, aluminum plates, and copper plates, and any laminates or alloys thereof; polymer substrates such as EPDM layers, PTFE layers, PE layers, and PP layers; and mineral substrates such as bitumen heavy layers.

[0041] According to any embodiment of this disclosure, the mold used to prepare the polyurethane foam may be a thin-walled mold. As used herein, the term “thin-walled mold” refers to a mold having a shallow cavity. In particular, thin / shallow cavities may have a longest dimension:shortest dimension ratio (e.g., length / thickness ratio of a rectangular cavity) of at least 5:1, e.g., 5:1 to 50:1, or 8:1 to 40:1, or 10:1 to 20:1, or 12:1 to 18:1, and a longest dimension:second longest dimension ratio (e.g., length / width ratio of a rectangular cavity) of about 4:1 to 1:1, e.g., 3:1 to 1:1, or 2:1 to 1:1, or 1.5:1 to 1:1. Although not bound by any particular theory, it is extremely difficult to prepare defect-free polyurethane foam, particularly defect-free viscoelastic polyurethane foam, in such thin-walled molds.

[0042] The resulting foam slabs or sheets can be sliced ​​and trimmed to desired dimensions according to the requirements of a particular application. Processing equipment and processing parameters for slab stock production and molding methods are generally known in the relevant field. For example, various components may be introduced individually or in various subcombinations into a mixing head or other mixing device, where they are mixed and dispensed into a region to be cured (such as a trough or other open container, or a closed mold). Often, especially when producing molded foam, it is advantageous to form a compounded polyol component containing polyols, amine-based catalysts, crosslinking agents, chain extenders (if present), and any other additives such as surfactants(s), foaming agents(s), and any combination thereof. This compounded polyol component is then brought into contact with an isocyanate compound (and any other components not present in the compounded polyol component) to produce a foam.

[0043] Some or all of the various components or constituents may be heated before mixing to form a reaction mixture. In other examples, the components or constituents are mixed at near ambient temperature (e.g., 15–40°C). After all components have been mixed, heat may be applied to the reaction mixture, but this is often unnecessary. Preferred conditions for accelerating the curing of the polyurethane polymer include temperatures of about 20°C to about 150°C, or about 30°C to about 120°C, or about 35°C to about 110°C, or about 40°C to about 50°C. In various embodiments, the temperature for curing may be selected at least in part based on the duration required for the polyurethane polymer to cure at that temperature. The curing time will also depend on other factors, including, for example, certain components (e.g., catalysts and their amounts), as well as the size and shape of the article being manufactured.

[0044] According to embodiments of this disclosure, the polyurethane foam product formed by the curing reaction has a yield of 5 to 200 kg / m². 3 For example, 8-180 kg / m 3 , or 10-160 kg / m 3 , or 12-150 kg / m3 , or 15-140 kg / m 3 , or 18-120 kg / m 3 , or 20-100 kg / m 3 , or 24-80 kg / m 3 , or 30-60 kg / m 3 , or 40-50 kg / m 3 Alternatively, it may have a density within a numerical range obtained by combining any two of the above-mentioned endpoint values.

[0045] The above description is intended to be general and not to include all possible embodiments of the invention. Similarly, the following examples are provided for illustrative purposes only and are not intended to define or limit the invention in any way. Those skilled in the art will recognize that other embodiments within the claims will become apparent from the specification and exercise of the invention disclosed herein. Such other embodiments may include choices such as specific components and their composition and proportions; mixing and reaction conditions, containers, dispensing apparatus and protocols; performance and selectivity; identification of products and by-products; and subsequent processing and use, and those skilled in the art will recognize that such may vary within the claims appended herein. Any embodiments obtained by combining any two or more of the embodiments specifically illustrated above or by combining any two or more of the technical features specifically illustrated above are also included in the concept of this disclosure. [Examples]

[0046] Herein, some embodiments of the present invention will be described in the following examples. However, the scope of this disclosure is naturally not limited to the formulations shown in these examples. Rather, the examples are simply relating to the invention of this disclosure.

[0047] The raw materials used in the examples are listed in Table 1 below. [Table 1]

[0048] Part A. General preparation procedures for polyurethane foam. In Examples 1-4 and Comparative Examples 1-11 of the invention, polyurethane foam was prepared by the following steps: Polyol components were obtained by mixing the polyols, crosslinking agents, surfactants, catalysts, and deionized water shown in Tables 2 and 3; isocyanate 1, isocyanate 2, and isocyanate 3 in the ratio "isocyanate 1:isocyanate 2:isocyanate 3 = 30:40:30" to obtain an isocyanate mixture, which was used as "isocyanate" as shown in Tables 2 and 3. a; a small amount of release agent was sprayed onto the inner surface of a thin, open mold measuring approximately 500 × 1200 × 25 mm, having a specific irregular shape including a circular insert that locally reduces the thickness to 10 mm, and dispersed with a wiping cloth; a reactive mixture was formed by combining a polyol component and an isocyanate, and this was immediately poured into the mold; the reactive mixture was allowed to foam and cure in the mold for 120 seconds, during which time the mold temperature was maintained at approximately 45°C; the cured polyurethane foam was then demolded and removed for characterization.

[0049] Part B. Characterization Techniques The vibration damping performance of the foam was determined using the damping coefficient parameter according to DIN 53426, and the experimental results are summarized in Tables 2 and 3 below. Foams with lower damping coefficients exhibit strong resonance peaks (amplification phenomena) at specific resonance frequencies, especially when the final foam is used as an item for noise suppression and vibration damping; therefore, a damping coefficient higher than 0.25 is desirable.

[0050] The number of voids with a diameter of 1 cm or more was counted on one surface of the aforementioned mold, and this count was used to score the aesthetic quality according to the following criteria. The experimental results are summarized in Tables 2 and 3 below. [Table 2]

[0051] Figures 1 and 2 show the polyurethane foam of Example 1 of the Invention, which has an excellent aesthetic score of 5, and the polyurethane foam prepared by Comparative Example 5, which has an inferior aesthetic score of 1. The irregular shape of the mold is emphasized, and the thin circular portion (10 mm thick, while the rest of the mold is 25 mm) is clearly visible on the right side. The comparison between Figure 1 and Figure 2 clearly shows the improved aesthetic performance of Example 1 of the Invention. Compounds that score at least 4 are considered useful for end-use and deliver surprisingly good performance. [Table 3] [Table 4]

[0052] As can be seen from Tables 2 and 3 above, all embodiments of the invention utilizing specially designed blends of the first, second, and third polyether polyols successfully achieved a combination of excellent defect-free aesthetic performance and good vibration damping performance.

[0053] In contrast, Comparative Examples 2, 5, and 8-11, in which one of the first to third polyether polyols was excluded, showed a significant decrease in both aesthetics and damping performance. The foams of Comparative Examples 2 and 5 were not viscoelastic, and their damping coefficients were less than 0.20. Comparative Examples 8 and 9 failed to produce stable viscoelastic foam panels, and significant thermal shrinkage was observed. Comparative Examples 10 and 11 showed the worst damping performance and undesirable aesthetic performance.

[0054] Comparative Example 1 was carried out by replacing the first polyether polyol with the same amount of polyol 4, which was identical to the first polyether polyol except that polyol 4 had a hydroxyl functional value of 3. Nevertheless, such a small difference resulted in a significant decrease in aesthetic performance.

[0055] In Comparative Examples 3-4 and 6-7, the relative ratios of the first to third polyether polyols were adjusted to levels exceeding a numerical range specifically selected for this disclosure, and such adjustments were also found to result in undesirable attenuation and aesthetic performance.

Claims

1. A polyurethane composition for preparing a viscoelastic polyurethane foam, (A) At least one isocyanate compound comprising at least two isocyanate groups, (b) (b1) Poly(C) with end protection at the ethylene oxide moiety ２ -C ６ An alkylene oxide-based polyol, a first polyether polyol having an OH functional value of 4 or more, (b2) Poly(C) with end protection at the propylene oxide portion ２ -C ６ A second polyether polyol having an alkylene oxide-based polyol with an OH functional value of 2 to 6, and (b3) Two or more (C ２ -C ６ ) A random copolymer of alkylene oxides, a third polyether polyol having an OH functional value of 2 to 6, A polyol blend containing, Includes, A polyurethane composition wherein the polyol blend comprises, when the total weight of the polyol blend is 100 pphp, the first polyether polyol in a concentration of 50 to 75 pphp, the second polyether polyol in a concentration of 20 to 35 pphp, and the third polyether polyol in a concentration of 5 to 20 pphp.

2. The first polyether polyol has an ethylene oxide content of 14% to 45% by weight based on the total weight of the first polyol. The second polyether polyol has a propylene oxide content of up to 100% by weight based on the total weight of the second polyol. The third polyether polyol has an ethylene oxide content of 55% to 90% by weight based on the total weight of the third polyol, or The polyurethane composition according to claim 1, which is any combination thereof.

3. The first polyether polyol is a poly(propylene oxide) polyol with an ethylene oxide moiety at the end, and has an OH functional value of 4 or more. The second polyether polyol is a poly(propylene oxide) polyol with a propylene oxide moiety at the end, and has an OH functional value of 2.5 to 6. The third polyether polyol is an ethylene oxide-propylene oxide random copolymer having an OH functional value of 2.5 to 6, or The polyurethane composition according to claim 1, which is any combination thereof.

4. The first polyether polyol is a poly(propylene oxide) polyol with an ethylene oxide moiety at the end, and has an OH functional value of 4 or more and an ethylene oxide content of 14% to 45% by weight based on the total weight of the first polyol. The second polyether polyol is a poly(propylene oxide) polyol with a propylene oxide moiety at the end, and has an OH functional value of 2.5 to 6 and a propylene oxide content of 5% to 100% by weight based on the total weight of the second polyol. The third polyether polyol is an ethylene oxide-propylene oxide random copolymer having an OH functional value of 2.5 to 6 and an ethylene oxide content of 55% to 90% by weight based on the total weight of the third polyol, or The polyurethane composition according to claim 1, which is any combination thereof.

5. The polyurethane composition according to claim 1, wherein the molecular weight of the first polyether polyol is 3,000 to 10,000, the molecular weight of the second polyether polyol is 150 to 2,500, and the molecular weight of the third polyether polyol is 1,550 to 10,000.

6. (C) Foaming agent, (D) catalyst; (E) Surfactants, (F) Chain extender, or The polyurethane composition according to claim 1, further comprising any combination thereof.

7. The polyurethane composition according to claim 6, wherein the foaming agent is water, formic acid, or a blend thereof.

8. The polyurethane composition according to claim 6, wherein the chain extender is diethanolamine, triethanolamine, or a blend thereof.

9. The polyurethane composition according to claim 1, further comprising at least one additive selected from the group consisting of crosslinking agents, cocatalysts, flame retardants, reinforcing agents, plasticizers, smoke suppressants, fragrances, adhesion promoters, mold release agents, antioxidants, foam stabilizers, tackifiers, rheology modifiers, UV absorbers, light stabilizers, fillers, colorants, pigments, solvents, diluents, anti-slip agents, antistatic agents, preservatives, biocides, and any combination thereof.

10. The isocyanate compound is a) A C containing at least two isocyanate groups ２ -C １２ aliphatic isocyanate compound, a C containing at least two isocyanate groups ６ -C １５ alicyclic isocyanate compound, a C containing at least two isocyanate groups ６ -C １５ aromatic isocyanate compound, a C containing at least two isocyanate groups ７ -C １５ aromatic aliphatic isocyanate compound, and any combination thereof, and b) one or more isocyanate compounds from a) having at least two hydroxyl groups, provided that the isocyanate prepolymer contains at least two free isocyanate groups. ２ ~C １６ Aliphatic polyhydric alcohols, C containing at least two hydroxyl groups ５ ~C １６ Alicyclic polyhydric alcohols containing at least two hydroxyl groups ６ ~C １６ Aromatic polyhydric alcohols containing at least two hydroxyl groups ７ ~C １５ An isocyanate prepolymer prepared by reacting one or more isocyanate-reactive components selected from the group consisting of aromatic aliphatic polyhydric alcohols, polyester polyols having a molecular weight of 500 to 5,000, polycarbonate polyols having a molecular weight of 200 to 5,000, polyether polyols having a molecular weight of 200 to 8,000, or any combination thereof. A polyurethane composition according to claim 1, selected from the group consisting of the following.

11. The polyurethane composition according to claim 1, comprising, based on the total weight of the polyurethane composition, 25% to 45% by weight of the isocyanate compound, 50% to 80% by weight of the polyol blend, 0.1% to 5% by weight of a blowing agent, 0% to 5% by weight of a catalyst, 0% to 5% by weight of a surfactant, and 0% to 5% by weight of a chain extender, wherein the total percentage of the total weight is 100%.

12. A viscoelastic polyurethane foam product prepared by using the polyurethane composition described in any one of claims 1 to 11.

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