Polyurethane foam

Abstract

This polyurethane foam is obtained by foaming and reacting a material mixture containing a polyisocyanate and a compound having an active hydrogen atom. The compound having an active hydrogen atom contains more than 40.0 mass% of a polyol A, more than 0 mass% of a polyol B, and more than 0 mass% but less than 15.0 mass% of a monool C. However, the "polyol A" refers to a polyether polyol having a weight average molecular weight of 3000 or more and having an EO percentage content of less than 50.0 mass%, the "polyol B" refers to a polyether polyol having an EO percentage content of 50.0 mass% or more, and the "monool C" refers to a monool having a weight average molecular weight of 2000 or more.

Description

Polyurethane foam

[0001] The present invention relates to a polyurethane foam, and more particularly to a polyurethane foam having low hardness, high resilience, and low compression set.

[0002] Polyurethane refers to a polymeric compound having a urethane bond (-NH-C(O)O-). Polyurethane is generally obtained by reacting the hydroxyl group (-OH) of a polyol with the isocyanate group (-NCO) of a polyisocyanate. It is known that polyurethane exhibits a variety of properties by optimizing the type of polyol and / or polyisocyanate. For this reason, polyurethane is used in various automobile parts, synthetic leather, paints, adhesives, etc. Furthermore, polyurethane foam, which is made by foaming polyurethane, is used in insulation materials, cushioning materials, etc.

[0003] Polyurethane foam with enhanced elasticity is also known as "high-resilience polyurethane foam." High-resilience polyurethane foam has strong resilience and is resistant to settling, making it suitable for use in apparel, sporting goods, toys, bedding, interior decor, and more.

[0004] Various proposals have been made regarding such high-resilience polyurethane foams. For example, Patent Document 1 discloses a flexible polyurethane foam obtained by reacting a raw material mixture containing: (a) 70 parts by mass of a propylene oxide (PO)-ethylene oxide (EO) adduct of glycerin (molecular weight 3000), (b) 25 parts by mass of a PO adduct of pentaerythritol (molecular weight 2000), (c) 5 parts by mass of a PO-EO adduct of n-butanol (molecular weight 600), and (d) predetermined amounts of water, a 33% triethylenediamine dipropylene glycol solution, a dimethylsiloxane foam stabilizer, stannous octoate, and T-80 (an 80 / 20 mixture of 2,4-TDI and 2,6-TDI).

[0005] The document also states that by this method, (A) 25% ILD is 11.4 kg / 314 cm 2(B) a compression set of 7.3%; and (C) a rebound resilience of 42%.

[0006] Patent Document 2 discloses a flexible polyurethane foam obtainable by reacting a raw material composition containing: (a) 100 parts of polyether polyol (hydroxyl value 56); (b) 3 parts of polyether monool obtained by adding 7 mol of PO to 1 mol of n-butanol; and (c) predetermined amounts of water, a silicone foam stabilizer, stannous octoate, triethylenediamine, and T-80.

[0007] In the same document, the following results were obtained by this method: (A) Hardness was 9.7 kg / 314 cm 2 (B) a permanent deformation of 10.6%; and (C) a rebound resilience of 41%.

[0008] Patent Document 3 describes, although not a high-resilience polyurethane foam, the following: (a) 21.6 parts by mass of polyoxypropylene polyol (polyol A2) having an average number of hydroxyl groups of 2, a hydroxyl value of 14 mgKOH / g, and an EO content of 0%, (b) 30.2 parts by mass of polyoxypropylene polyol (polyol B1) having an average number of hydroxyl groups of 2, a hydroxyl value of 160 mgKOH / g, and an EO content of 0%, (c) 31.5 parts by mass of polyoxypropylene polyol (polyol B2) having an average number of hydroxyl groups of 3, a hydroxyl value of 168 mgKOH / g, and an EO content of 0%, (d) 2.8 parts by mass of polyoxypropylene oxyethylene polyol (polyol B3) having an average number of hydroxyl groups of 3, a hydroxyl value of 48 mgKOH / g, and an EO content of 80%, Disclosed is a low-resilience flexible polyurethane foam obtainable by reacting a raw material mixture containing: (e) 13.9 parts by mass of polyoxypropylene monool (monool D1) having an average number of hydroxyl groups of 1 and a hydroxyl value of 16.7 mgKOH / g; and (f) predetermined amounts of a blowing agent, a foam stabilizer, a catalyst, and a polyisocyanate compound.

[0009] The document also describes the following: (A) 25% ILD is 73 N / 314 cm 2(B) the dry heat compression set is 2.3%, and (C) the core rebound resilience is 13%.

[0010] Patent Document 4 describes, although not a high-resilience polyurethane foam, the following: (a) 26.3 parts by mass of polyoxypropylene polyol (polyol A1) having an average number of hydroxyl groups of 2, a hydroxyl value of 18 mgKOH / g, and an EO content of 0%, (b) 36.8 parts by mass of polyoxypropylene polyol (polyol B1) having an average number of hydroxyl groups of 2, a hydroxyl value of 160 mgKOH / g, and an EO content of 0%, (c) 27.0 parts by mass of polyoxypropylene polyol (polyol B2) having an average number of hydroxyl groups of 3, a hydroxyl value of 168 mgKOH / g, and an EO content of 0%, (d) 5.4 parts by mass of polyoxypropyleneoxyethylene polyol (polyol C1) having an average hydroxyl value of 3, a hydroxyl value of 48 mgKOH / g, and an EO content of 80%, Disclosed is a low-resilience flexible polyurethane foam obtainable by reacting a raw material mixture containing: (e) 4.5 parts by mass of polyoxypropylene monool (monool D1) having an average number of hydroxyl groups of 1 and a hydroxyl value of 16.7 mgKOH / g; and (f) predetermined amounts of a blowing agent, a catalyst, a foam stabilizer, and a polyisocyanate compound.

[0011] The document also describes the following: (A) 25% ILD is 48N / 314cm by this method. 2 (B) the dry heat compression set is 3.2%, and (C) the core rebound resilience is 11%.

[0012] Patent Document 5 does not disclose a high-resilience polyurethane foam, but describes a polyurethane foam containing: (a) 27.7 parts by mass of a polyoxypropylene polyol (polyol A1) having an average number of hydroxyl groups of 2, a hydroxyl value of 14 mgKOH / g, and an EO content of 0%, (b) 38.8 parts by mass of a polyoxypropylene polyol (polyol B1) having an average number of hydroxyl groups of 2, a hydroxyl value of 160 mgKOH / g, and an EO content of 0%, (c) 31 parts by mass of a polyoxypropylene polyol (polyol B2) having an average number of hydroxyl groups of 3, a hydroxyl value of 168 mgKOH / g, and an EO content of 0%, (d) 6 parts by mass of a polyoxypropylene oxyethylene polyol (polyol C) having an average number of hydroxyl groups of 3, a hydroxyl value of 48 mgKOH / g, and an EO content of 80%, Disclosed is a low-resilience flexible polyurethane foam obtainable by reacting a raw material composition containing: (e) 7.5 parts by mass of polyoxypropylene monool (monool D) having an average number of hydroxyl groups of 1 and a hydroxyl value of 17 mgKOH / g; and (f) predetermined amounts of a catalyst, a blowing agent, a foam stabilizer, and a polyisocyanate compound.

[0013] The document also describes the following: (A) 25% ILD is 13N / 314cm by this method. 2 (B) the dry heat compression set is 42.1%; and (C) the rebound resilience is 1%.

[0014] Patent Document 6 describes, although not a high-resilience polyurethane foam, the following: (a) 21.2 parts by mass of polyoxypropylene polyol (polyol A1) having an average number of hydroxyl groups of 2, a hydroxyl value of 11 mgKOH / g, and an EO content of 0%, (b) 29.7 parts by mass of polyoxypropylene polyol (polyol B1) having an average number of hydroxyl groups of 2, a hydroxyl value of 160 mgKOH / g, and an EO content of 0%, (c) 36.9 parts by mass of polyoxypropylene polyol (polyol B2) having an average number of hydroxyl groups of 3, a hydroxyl value of 168 mgKOH / g, and an EO content of 0%, (d) 5.4 parts by mass of polyoxypropyleneoxyethylene polyol (polyol C1) having an average number of hydroxyl groups of 3, a hydroxyl value of 48 mgKOH / g, and an EO content of 80%, Disclosed is a low-resilience flexible polyurethane foam obtainable by reacting a raw material composition containing: (e) 6.8 parts by mass of polyoxypropylene monool (monool D1) having an average number of hydroxyl groups of 1 and a hydroxyl value of 16.7 mgKOH / g; and (f) predetermined amounts of a blowing agent, a foam stabilizer, a catalyst, and a polyisocyanate compound.

[0015] The document also describes the following: (A) 25% ILD is 53 N / 314 cm 2 (B) a 50% compression residual set of 20.7%; and (C) a core rebound resilience of 11%.

[0016] Polyurethane foams used in certain applications (e.g., apparel applications) are required to have not only high resilience but also softness to the touch. Known methods for softening polyurethane foam include (A) a method using a high-molecular-weight polyol, (B) a method using a polyol with a high EO content, and (C) a method using a low-molecular-weight monool.

[0017] However, the method of softening the polyurethane foam using only a high molecular weight polyol tends to result in closed-cell structures, which can lead to problems such as: (a) although the hardness of the polyurethane foam itself is reduced, a "tension" occurs and the polyurethane foam remains hard to the touch; (b) the compression set of the polyurethane foam increases; and (c) the breathability of the polyurethane foam is reduced.

[0018] Furthermore, the method of softening the polyurethane foam by using a large amount of polyol with a high EO content may cause problems such as: (a) the hydrophilicity of the polyurethane foam increases, thereby decreasing water resistance; (b) the polyurethane foam absorbs moisture, causing adhesion (stickiness) between cell walls, thereby decreasing resilience; and (c) excessive cell communication, resulting in cell roughness.

[0019] Furthermore, in the method of softening the polyurethane foam using only a low-molecular-weight monol, polymerization stops at the monol portion, reducing the crosslinking density of the polymer and decreasing the strength of the resin, which may result in problems such as: (a) a decrease in the resilience of the polyurethane foam; and (b) an increase in the compression set of the polyurethane foam.

[0020] Japanese Patent Application Laid-Open No. 04-146916 Japanese Patent Application Laid-Open No. 05-287047 International Publication No. 2006 / 115169 International Publication No. 2008 / 050841 International Publication No. 2009 / 041535 Japanese Patent Application Laid-Open No. 2013-127011

[0021] The problem to be solved by the present invention is to provide a novel polyurethane foam which has low hardness, high resilience and low compression set.

[0022] In order to solve the above problems, a polyurethane foam according to a first embodiment of the present invention is obtained by foaming and reacting a raw material mixture containing: a compound having an active hydrogen atom; and a polyisocyanate, wherein the compound having an active hydrogen atom contains more than 40.0 mass% of polyol A, more than 0 mass% of polyol B, and more than 0 mass% and less than 15.0 mass% of monool C.

[0023] However, the "polyol A" refers to one or more polyether polyols having a weight-average molecular weight of 3,000 or more and an EO content of less than 50.0 mass%, the "polyol B" refers to one or more polyether polyols having an EO content of 50.0 mass% or more, the "monool C" refers to one or more monools having a weight-average molecular weight of 2,000 or more, and the "mass %" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C, respectively, to the total mass of the compound having an active hydrogen atom.

[0024] The polyurethane foam according to the second embodiment of the present invention uses Monool C having a weight average molecular weight of 2000 or more as a raw material, has a rebound resilience of 35% or more, and an Asker F hardness of 35 or less. The "rebound resilience" refers to a value measured in accordance with JIS K6255.

[0025] When producing polyurethane foam, adding monool C (an ether-based high-molecular-weight monool) as a raw material results in a polyurethane foam with low hardness, high resilience, and low compression set. This is thought to be due to the use of monool C, which reduces the crosslink density and increases the repulsive force between molecules.

[0026] An embodiment of the present invention will be described in detail below. [1. Polyurethane foam (1)] A polyurethane foam according to a first embodiment of the present invention is obtained by foaming and reacting a raw material mixture containing a compound having an active hydrogen atom and a polyisocyanate.

[0027] [1.1. Components] The raw material mixture contains at least a compound having an active hydrogen atom and a polyisocyanate. In addition to these, the raw material mixture usually further contains a blowing agent, a catalyst, a foam stabilizer, etc.

[0028] [1.1.1. Compound Having an Active Hydrogen Atom] A "compound having an active hydrogen atom (hereinafter also referred to as an "active hydrogen compound")" refers to a compound having one or more "functional groups having an active hydrogen atom" in the molecule. Examples of functional groups having an active hydrogen atom include a hydroxyl group, an amino group, an imino group, a carboxyl group, a urethane group, and a urea group. In the present invention, the active hydrogen compound includes at least polyol A, polyol B, and monool C, which will be described later. The active hydrogen compound may further include a polyol and / or monool other than these.

[0029] [A. Polyol A] [A. 1. Definition] In the present invention, "polyol A" refers to a polyether polyol (an ether-based high molecular weight polyol) having a weight average molecular weight of 3,000 or more and an EO content of less than 50.0 mass%. Polyol A is one of the main raw materials for producing polyurethane foam. Polyol A may consist of any one polyether polyol satisfying the above conditions, or may be a mixture of two or more polyether polyols.

[0030] [A. 2. Weight-average molecular weight] In the present invention, the "weight-average molecular weight" refers to a value calculated from a chromatogram measured by gel permeation chromatography (GPC) based on the molecular weight of standard polyethylene. If the weight-average molecular weight of polyol A is too small, the proportion of soft segments present will decrease, and the hardness of the polyurethane foam may become excessively high. Therefore, the weight-average molecular weight of polyol A must be 3,000 or more. The weight-average molecular weight is preferably 4,500 or more, or 6,000 or more.

[0031] On the other hand, if the weight-average molecular weight of polyol A is too large, the ratio of urethane bonds (the ratio of hard segments) becomes excessively low, and the required hardness may not be obtained. Furthermore, even if the raw material mixture is foamed during reaction, bubbles may escape from the raw material mixture during curing, making it difficult to maintain the foam (no foam may be formed). Furthermore, the viscosity of the raw material mixture may become excessively high, which may cause poor stirring of the raw material mixture and lead to unevenness. Therefore, the weight-average molecular weight of polyol A is preferably 12,000 or less. The weight-average molecular weight is preferably 11,000 or less, 10,000 or less, or 9,000 or less.

[0032] [A. 3. EO Content] The "EO content (mass %)" of polyol A refers to the ratio of the mass of ethylene oxide (EO) units to the total mass of alkylene oxide units contained in polyol A. Polyol A contains alkylene oxide units other than EO units. In this case, the type of alkylene oxide units other than EO units is not particularly limited, but propylene oxide (PO) units are preferred.

[0033] If the EO content of polyol A becomes too high, so-called "cell roughness" may occur. That is, some cells may associate with each other to form larger cells, resulting in non-uniform cell sizes. In addition, some cells may be lost along with the cell membrane, leaving only the cell skeleton. Therefore, the EO content of polyol A must be less than 50.0 mass%. The EO content is preferably 25.0 mass% or less, 20.0 mass% or less, or 16.0 mass% or less.

[0034] On the other hand, if the EO content of polyol A is too low, the bubbles tend to become closed cells. As a result, the degassing effect may be insufficient, and the foam may feel hard to the touch. In addition, the foam may be constricted (i.e., shrink) during the cooling process after the reaction. Therefore, the EO content of polyol A is preferably 5.0 mass% or more. The EO content is more preferably 8.0 mass% or more, 10.0 mass% or more, or 12.0 mass% or more.

[0035] [A. 4. Number of Functional Groups] The number of functional groups of polyol A is not particularly limited, and an optimal value can be selected depending on the purpose. Generally, if the number of functional groups of polyol A is too small, the formation of a three-dimensional network structure may be insufficient, making it difficult to thermally cure. Therefore, the number of functional groups of polyol A is preferably 2.5 or more. The number of functional groups is more preferably 2.6 or more, or 2.7 or more.

[0036] On the other hand, if the number of functional groups in polyol A is too large, the hardness of the polyurethane foam may become excessively high. Therefore, the number of functional groups in polyol A is preferably 4.0 or less, more preferably 3.5 or less, or even 3.3 or less.

[0037] [B. Polyol B] [B. 1. Definition] In the present invention, "polyol B" refers to a polyether polyol (ether-based high-EO polyol) having an EO content of 50.0 mass% or more. Polyol B is a secondary raw material for controlling the hardness and breathability of polyurethane foam. Polyol B may consist of any one polyether polyol satisfying the above conditions, or may be a mixture of two or more polyether polyols.

[0038] [B. 2. EO Content] The "EO content (mass %)" of polyol B refers to the ratio of the mass of ethylene oxide (EO) units to the total mass of alkylene oxide units contained in polyol B. Polyol B may contain alkylene oxide units other than EO units. In this case, the type of alkylene oxide units other than EO units is not particularly limited, but propylene oxide (PO) units are preferred.

[0039] If the EO content of polyol B is too low, the function as a degassing agent (the function of opening gas bubbles) may be impaired. Therefore, the EO content of polyol B needs to be 50.0 mass% or more. The EO content is preferably 60.0 mass% or more, or 70.0 mass% or more. The EO content of polyol B may be 100.0 mass%.

[0040] [B.3. Weight-average molecular weight] The weight-average molecular weight of polyol B is not particularly limited, and an optimum value can be selected depending on the purpose. Generally, if the weight-average molecular weight of polyol B is too small, the hardness of the polyurethane foam may become excessively high. Therefore, the weight-average molecular weight of polyol B is preferably 2,500 or more. The weight-average molecular weight is more preferably 2,700 or more, or 3,000 or more.

[0041] On the other hand, if the weight-average molecular weight of polyol B is too large, the ratio of urethane bonds (the ratio of hard segments) becomes excessively low, and the required hardness may not be obtained. Furthermore, even if the raw material mixture is foamed during reaction, bubbles may escape from the raw material mixture during curing, making it difficult to maintain the foam (no foam may be formed). Furthermore, the viscosity of the raw material mixture may become excessively high, which may cause poor stirring of the raw material mixture and lead to unevenness. Therefore, the weight-average molecular weight of polyol B is preferably 12,000 or less. The weight-average molecular weight is more preferably 10,000 or less, 8,000 or less, 6,000 or less, or 4,000 or less.

[0042] [B. 4. Number of Functional Groups] The number of functional groups of polyol B is not particularly limited, and an optimum value can be selected depending on the purpose. Generally, if the number of functional groups of polyol B is too small, the formation of a three-dimensional network structure may be insufficient, making it difficult to thermally cure. Therefore, the number of functional groups of polyol B is preferably 2.5 or more. The number of functional groups is more preferably 2.6 or more, or 2.7 or more.

[0043] On the other hand, if the number of functional groups in polyol B is too large, the hardness of the polyurethane foam may become excessively high. Therefore, the number of functional groups in polyol B is preferably 3.5 or less. The number of functional groups is more preferably 3.4 or less, or 3.3 or less.

[0044] [C. Monool C] [C. 1. Definition] In the present invention, "monool C" refers to a monool (ether-based high-molecular-weight monool) having a weight-average molecular weight of 2000 or more. Monool C is a secondary raw material for controlling the hardness, resilience, and compression set of polyurethane foam. Monool C may consist of any one type of monool satisfying the above conditions, or may be a mixture of two or more types of monools.

[0045] [C. 2. Weight Average Molecular Weight] If the weight average molecular weight of monol C is too small, the compression set of the polyurethane foam may increase. Therefore, the weight average molecular weight of monol C must be 2,000 or more. The weight average molecular weight is preferably 2,300 or more, 2,600 or more, 2,900 or more, or 3,000 or more. On the other hand, if the weight average molecular weight of monol C is too large, the cells may become closed cells, and the polyurethane foam may shrink during the cooling process after the reaction. Therefore, the weight average molecular weight of monol C is preferably 12,000 or less. The weight average molecular weight is preferably 10,000 or less, 8,000 or less, or 6,000 or less.

[0046] [C. 3. EO Content] The "EO content" of monool C refers to the ratio of the mass of ethylene oxide (EO) units to the total mass of alkylene oxide units contained in monool C.

[0047] In the present invention, the EO content of monool C is not particularly limited, and an optimum value can be selected depending on the purpose. The EO content of monool C is usually 0 mass%, but can be any value between 0 and 100 mass%. When monool C contains alkylene oxide units other than EO units, the type of alkylene oxide units other than EO units is not particularly limited, but propylene oxide (PO) units are preferred.

[0048] [C. 4. Number of Functional Groups] Theoretically, the number of functional groups of monool C is 1. However, impurities (polyols) are inevitably mixed into monool C, and the apparent number of functional groups of monool C may exceed 1. In the present invention, monool C may have a number of functional groups exceeding 1. However, if the number of functional groups of monool C is too large, the hardness of the polyurethane foam may become excessively high. Therefore, the number of functional groups of monool C is preferably 1.1 or less. The number of functional groups is more preferably 1.05 or less, 1.03 or less, or 1.01 or less.

[0049] [D. Other Polyols and Monools] The active hydrogen compound may contain only polyol A, polyol B, and monool C, or may further contain other polyols and / or monools.

[0050] Examples of other polyols and monools include the following: (a) polyether polyols other than polyol A and polyol B (b) monools other than monool C (c) polyester polyols (d) polymer polyols (e) polycarbonate diols (f) polyolefin polyols (g) plant-derived polyols

[0051] [1.1.2. Polyisocyanate] "Polyisocyanate" is another main raw material for producing polyurethane foam, and refers to a compound having two or more isocyanate groups in one molecule. In the present invention, the type of polyisocyanate is not particularly limited. Furthermore, the raw material mixture may contain one type of polyisocyanate, or two or more types.

[0052] Examples of polyisocyanates include: (a) aromatic isocyanate compounds, aliphatic isocyanate compounds, and alicyclic isocyanate compounds; and (b) modified products of the above compounds.

[0053] Examples of aromatic isocyanate compounds include diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate, tolylene diisocyanate (TDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), and tolidine diisocyanate (TODI).

[0054] Among these, MDI is suitable as a polyisocyanate for producing polyurethane foam. MDI exists as three isomers: 2,2'-diphenylmethane diisocyanate (2,2'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'-MDI), and 4,4'-diphenylmethane diisocyanate (4,4'-MDI). The polyisocyanate may contain any one of these isomers, or may contain two or more of them.

[0055] Examples of the aliphatic isocyanate compound include hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI).

[0056] Examples of alicyclic isocyanate compounds include isophorone diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H 12 MDI) and the like.

[0057] Examples of modified isocyanate compounds include urethane-modified isocyanate compounds, dimers, trimers, carbodiimide-modified isocyanate compounds, allophanate-modified isocyanate compounds, biuret-modified isocyanate compounds, urea-modified isocyanurate-modified isocyanate compounds, oxazolidone-modified isocyanate compounds, and isocyanate-terminated prepolymers.

[0058] [1.1.3. Blowing Agent] A "blowing agent" refers to an additive that generates bubbles in the raw material mixture during the process of resinification of the liquid raw material mixture. In the present invention, the blowing agent may be either: (a) a physical blowing agent that generates gas by reducing pressure or by heating, or (b) a chemical blowing agent that generates gas by thermal decomposition or chemical reaction.

[0059] Examples of physical foaming agents include: (a-1) hydrocarbons such as cyclopentane, isopentane, and normal pentane; and (a-2) halogen-based compounds such as methylene chloride, trichlorofluoromethane, dichlorodifluoromethane, nonafluorobutyl methyl ether, pentafluoroethyl methyl ether, and pentafluoroisopropyl methyl ether.

[0060] Examples of chemical foaming agents include (b-1) water, which reacts with isocyanate groups to generate CO2, and (b-2) azodicarbonamide, which generates nitrogen, carbon monoxide, carbon dioxide, or ammonia gas through thermal decomposition.

[0061] The raw material mixture may contain any one of these blowing agents, or two or more of them. Among these, water is preferred as the blowing agent. When water is used as the blowing agent, CO2 gas generated by the reaction between water and isocyanate groups promotes foaming. In addition, the heat of reaction between water and isocyanate groups promotes the curing of the resin.

[0062] [1.1.4. Catalyst] The term "catalyst" refers to a catalyst that promotes a resinification reaction, a catalyst that promotes a foaming reaction, or a catalyst that promotes both a resinification reaction and a foaming reaction.

[0063] Examples of catalysts include amine catalysts and metal catalysts. The amine catalyst is a catalyst that promotes both the resinification reaction and the foaming reaction. The metal catalyst is a catalyst that promotes the resinification reaction. The raw material mixture may contain one of these catalysts, or two or more of them.

[0064] Examples of the amine catalyst include N,N-dimethylcyclohexylamine, N,N-dimethylbenzylamine, N,N-dimethylaminoethanol, N,N',N'-trimethylaminoethylpiperazine, and triethylenediamine.

[0065] Examples of the metal catalyst include: (a) tin catalysts such as stannous octoate and dibutyltin dilaurate; (b) mercury catalysts such as phenylmercury propionate; and (c) lead catalysts such as lead octenate.

[0066] [1.1.5. Foam Stabilizer] A "foam stabilizer" is an additive that has the effect of uniforming the size and distribution of bubbles. Adding a foam stabilizer to a raw material mixture makes it possible to obtain polyurethane foam with uniform bubble size and distribution. Examples of foam stabilizers include silicone-based foam stabilizers, fluorine-containing compound-based foam stabilizers, and known surfactants.

[0067] [1.2. Content] [1.2.1. Content of Polyol A] "Content of Polyol A (mass %)" refers to the ratio of the mass of Polyol A to the total mass of active hydrogen compounds.

[0068] If the content of polyol A is too low, the hardness may increase, the resilience may decrease, or the compression set may increase. Therefore, the content of polyol A needs to be more than 40.0 mass%. The content is preferably 50.0 mass% or more, 60.0 mass% or more, 70.0 mass% or more, or 80.0 mass% or more. On the other hand, if the content of polyol A is excessive, the compression set may increase. Furthermore, if the content of polyol A is excessive, closed cells may be easily formed. Therefore, during the cooling process after the reaction, the polyurethane foam may shrink and the resilience may decrease. Therefore, the content of polyol A needs to be less than 100.0 mass%. The content is preferably 95.0 mass% or less, or 90.0 mass% or less.

[0069] [1.2.2. Content of Polyol B] The "content of polyol B (mass %)" refers to the ratio of the mass of polyol B to the total mass of active hydrogen compounds.

[0070] If the content of polyol B is too low, the degassing effect may be insufficient, and the polyurethane foam may become hard. Furthermore, the polyurethane foam may shrink during the cooling process after the reaction. Therefore, the content of polyol B must be more than 0.0 mass%. The content is preferably 0.5 mass% or more, 1.0 mass% or more, or 2.0 mass% or more.

[0071] On the other hand, if the content of polyol B is excessive, cell roughening may occur. Also, some of the cells may be lost together with the cell membrane, leaving only the cell skeleton. Therefore, the content of polyol B is preferably 25.0 mass% or less. The content is preferably 20.0 mass% or less, 15.0 mass% or less, 12.0 mass% or less, or 10.0 mass% or less.

[0072] [1.2.3. Content of Monool C] The "content of monool C (mass %)" refers to the ratio of the mass of monool C to the total mass of active hydrogen compounds.

[0073] If the content of monol C is too low, the hardness may increase, the resilience may decrease, or the compression set may increase. Therefore, the content of monol C must be more than 0.0 mass%. The content is preferably 1.0 mass% or more, 2.0 mass% or more, 3.0 mass% or more, or 4.0 mass% or more. On the other hand, if the content of monol C is excessive, the ratio of urethane bonds (the ratio of hard segments) may become too low, and the required hardness may not be obtained. Furthermore, even if the raw material mixture is foamed during reaction, air bubbles may escape from the raw material mixture during curing, making it difficult to maintain the foam (no foam may be formed). Therefore, the content of monol C must be less than 15.0 mass%. The content is preferably 14.0 mass% or less, or 13.0 mass% or less.

[0074] [1.2.4. Content of Other Polyols and Monools] "Content of other polyols and monools (mass %)" refers to the ratio of the total mass of other polyols and monools to the total mass of active hydrogen compounds.

[0075] The active hydrogen compound may contain polyols and / or monools other than the above-mentioned polyol A, polyol B, and monool C. However, excessive content of the other polyols and monools may increase hardness, decrease resilience, or increase compression set. Therefore, the content of the other polyols and monools is preferably 50.0 mass% or less. The content is more preferably 25.0 mass% or less, 10.0 mass% or less, or 5.0 mass% or less.

[0076] [1.2.5. Isocyanate Index] The term "isocyanate index" refers to the ratio of the equivalent weight of isocyanate groups of the polyisocyanate in the raw material mixture to the equivalent weight of active hydrogen groups in the raw material mixture, multiplied by 100.

[0077] In the present invention, the isocyanate index is not particularly limited, and an optimum value can be selected depending on the purpose. Generally, the higher the isocyanate index, the greater the number of crosslinking points, thereby improving the strength and toughness of the polyurethane foam. Therefore, the isocyanate index is preferably 80 or more. The isocyanate index is more preferably 85 or more, or 90 or more. On the other hand, if the isocyanate index is too high, the hardness of the polyurethane foam may become excessively high. Therefore, the isocyanate index is preferably 110 or less. The isocyanate index is more preferably 105 or less, or 100 or less.

[0078] [1.2.6. Content of Blowing Agent] The "content of blowing agent" refers to the mass of the blowing agent when the total mass of the active hydrogen compounds is taken as 100.

[0079] The content of the blowing agent is preferably selected optimally depending on the type of blowing agent. For example, when the blowing agent is water, generally, the higher the water content, the lower the hardness of the polyurethane foam. To achieve this effect, the water content is preferably 1.0 part by mass or more. The content is more preferably 1.5 parts by mass or more, or 2.0 parts by mass or more. On the other hand, an excessive water content may cause cell roughness in the polyurethane foam or a deterioration in the feel. Therefore, the water content is preferably 8.0 parts by mass or less. The content is more preferably 5.0 parts by mass or less, or 3.0 parts by mass or less.

[0080] [1.2.7. Catalyst Content] The term "catalyst content" refers to the mass of the catalyst when the total mass of the active hydrogen compounds is taken as 100.

[0081] Generally, the higher the catalyst content, the shorter the reaction time. To achieve this effect, the catalyst content is preferably 0.5 parts by mass or more. The content is more preferably 0.6 parts by mass or more, or 0.7 parts by mass or more. On the other hand, if the catalyst content is excessive, the polyurethane foam may become excessively hard. Therefore, the catalyst content is preferably 1.5 parts by mass or less. The content is more preferably 1.4 parts by mass or less, or 1.3 parts by mass or less.

[0082] [1.2.8. Content of foam stabilizer] The "content of foam stabilizer" refers to the mass of the foam stabilizer when the total mass of the active hydrogen compounds is taken as 100.

[0083] If the content of the foam stabilizer is too low, it may be difficult to form a foam. Therefore, the content of the foam stabilizer is preferably 0.5 parts by mass or more. The content is more preferably 0.6 parts by mass or more, or 0.7 parts by mass or more. On the other hand, if the content of the foam stabilizer is excessive, closed cells may be formed, impairing breathability, or the foam may shrink after foaming, making the foam feel hard to the touch. Therefore, the content of the foam stabilizer is preferably 1.5 parts by mass or less. The content is more preferably 0.9 parts by mass or less, or 0.8 parts by mass or less.

[0084] [1.3. Reaction] Polyisocyanate (liquid B) is added to a raw material mixture (liquid A) containing an active hydrogen compound and other additives, and the mixture is maintained at a predetermined temperature, whereby a foaming reaction and a resinification reaction occur, resulting in the production of a polyurethane foam according to the present invention.

[0085] 1.4. Properties 1.4.1. Rebound resilience The term "rebound resilience" refers to a value measured in accordance with JIS K6255.

[0086] The polyurethane foam of the present invention exhibits high resilience because it uses Monool C, which satisfies certain conditions, as a raw material. When the manufacturing conditions are optimized, the resilience modulus becomes 35% or more. When the manufacturing conditions are further optimized, the resilience modulus becomes 40% or more, or even 45% or more.

[0087] [1.4.2. Asker F Hardness] "Asker F hardness" refers to a value measured using an Asker rubber hardness tester, type F.

[0088] The polyurethane foam of the present invention exhibits low hardness because it uses Monool C, which satisfies the specified conditions, as a raw material. When the production conditions are optimized, the Asker F hardness becomes 35 or less. When the production conditions are further optimized, the Asker F hardness becomes 33 or less, or even 30 or less.

[0089] [1.4.3. Compression Set] "Compression set" refers to a value measured in accordance with JIS K6400-3 (50% compression).

[0090] The polyurethane foam of the present invention exhibits low compression set because it uses Monool C, which satisfies the specified conditions, as a raw material. When the manufacturing conditions are optimized, the compression set is 20% or less. When the manufacturing conditions are further optimized, the compression set is 17% or less, or even 16% or less.

[0091] [2. Polyurethane Foam (2)] The polyurethane foam according to the second embodiment of the present invention uses Monool C having a weight average molecular weight of 2000 or more as a raw material, has a rebound resilience of 35% or more, and has an Asker F hardness of 35 or less.

[0092] [2.1. Monool C] "Monool C" refers to a monool (ether-based high-molecular-weight monool) having a weight-average molecular weight of 2000 or more. Details of monool C are as described above, and therefore will not be described here.

[0093] [2.2. Rebound resilience] The polyurethane foam according to this embodiment has a rebound resilience of 35% or more. Other aspects related to the rebound resilience are the same as those in the first embodiment, and therefore will not be described further.

[0094] [2.3. Asker F Hardness] The polyurethane foam according to this embodiment has an Asker F hardness of not more than 35. Other aspects relating to the Asker F hardness are the same as those of the first embodiment, and therefore will not be described further.

[0095] [3. Method for Producing Polyurethane Foam] The polyurethane foam according to the present invention can be produced by mixing the above-described components to form a raw material mixture and then carrying out a resinification reaction and a foaming reaction. The resinification reaction and the foaming reaction can be carried out by freely combining conventional methods as long as the object and effect of the present invention are not impaired.

[0096] The foaming method for producing polyurethane foam according to the present invention can be either slab foaming or mold foaming. Slab foaming is a method in which raw materials for producing polyurethane foam are mixed and discharged onto a belt conveyor, and foamed at atmospheric pressure and room temperature. Mold foaming is a method in which raw materials for producing polyurethane foam are mixed and injected into a cavity of a mold (metal mold), and foamed to the shape of the cavity.

[0097] [4. Function] When producing a polyurethane foam, adding Monool C (an ether-based high-molecular-weight monool) as a raw material makes it possible to obtain a polyurethane foam that has low hardness, high resilience, and low compression set.

[0098] The decrease in hardness is thought to be due to the moderate reduction in the proportion of hard segments (urethane bonds) in the polymer chain by adding an appropriate amount of Monool C. The improvement in resilience or the suppression of a decrease in compression set is thought to be due to the fact that the addition of an appropriate amount of Monool C increases the length of the terminal alkyl groups, thereby strengthening the repulsive action between molecules due to the free long-chain alkyl groups.

[0099] (Examples 1 to 7, Comparative Examples 1 to 9) [1. Preparation of Samples] [1.1. Raw Materials] The following polyols were used. (1) Polyol A: Polyether polyol, weight average molecular weight 7000, number of functional groups 3, EO content 15.5 mass%, product name: KC-737, manufactured by Sanyo Chemical Industries, Ltd. (2) Polyol B: Polyether polyol, weight average molecular weight 3400, number of functional groups 3, EO content 72 mass%, product name: EP-505S, manufactured by Mitsui Chemicals, Inc. (3) Polyol D: Polyether polyol, weight average molecular weight 2000, number of functional groups 2, EO content 0 mass%, product name: D-2000, manufactured by Mitsui Chemicals, Inc. (4) Polyol E: Polyether polyol, weight average molecular weight 750, number of functional groups 3, EO content 0 mass%, product name: GP750NS, manufactured by Sanyo Chemical Industries, Ltd.

[0100] The following mono-ols were used: (1) Mono-ol C1: Polyether mono-ol, weight average molecular weight 3000, number of functional groups 1, EO content 0 mass%, product name: ML-3000, manufactured by Mitsui Chemicals, Inc. (2) Mono-ol C2: Polyether mono-ol, weight average molecular weight 5000, number of functional groups 1, EO content 0 mass%, product name: ML-5000, manufactured by Mitsui Chemicals, Inc. (3) Mono-ol F: Polyether mono-ol, weight average molecular weight 470, number of functional groups 1, EO content 0 mass%, product name: CA-120, manufactured by Mitsui Chemicals, Inc.

[0101] The following resinification catalyst, foam stabilizer, blowing agent, and polyisocyanate were used: (1) Resinification catalyst: Triethylenediamine 33%, Product name: DABCO 33LSI, manufactured by Eponic Japan Co., Ltd. (2) Foam stabilizer: Silicone foam stabilizer, Product name: B8742FL2, manufactured by Eponic Japan Co., Ltd. (3) Blowing agent: Water (4) Polyisocyanate: Monomeric MDI (diphenylmethane diisocyanate), NCO content 33.6%, Product name: Lupranate (registered trademark) MI, manufactured by BASF Inoac Polyurethanes Co., Ltd.

[0102] Table 1 shows a list of the raw materials used.

[0103]

[0104] [1.2. Formation of Foam] The above raw materials were mixed in a predetermined ratio to obtain a raw material mixture. The raw material mixture was poured into a mold maintained at 65°C, and the raw material mixture was foamed in the mold. The mold was then placed in an oven set at 70°C to harden the foam.

[0105] [2. Test Method] [2.1. Hardness] Asker F hardness was measured using an Asker rubber hardness tester, model F. [2.2. Rebound elasticity] Rebound elasticity was measured in accordance with JIS K6255.

[0106] [2.3. Compression set] Compression set was measured in accordance with JIS K6400-3. However, the compression ratio was 50% or 25% of the original thickness. [2.4. Foam state] The presence or absence of cell roughness was evaluated visually.

[0107] [3. Results] The results are shown in Tables 2 and 3. Tables 2 and 3 also show the raw material composition of each sample. The numerical values ​​for the raw material composition represent parts by mass. Tables 2 and 3 reveal the following:

[0108] (1) In Comparative Examples 1 and 2, the hardness increased. This is thought to be because the proportion of hard segments increased due to the absence of monools C1 and C2. (2) In Comparative Example 3, the compression set increased. This is thought to be because the use of low-molecular-weight monool F shortened the terminal alkyl chains, making it easier for cell walls to adhere to each other.

[0109] (3) In Comparative Examples 4 and 5, the hardness increased, the rebound resilience decreased, and the compression set increased. This is thought to be due to the low content of polyol A. (4) In Comparative Example 6, the hardness increased and the compression set also increased. This is thought to be due to the absence of polyol B, which reduced breathability. (5) In Comparative Examples 7 to 9, no foam could be formed. This is thought to be due to the excessive content of monool C2, which resulted in insufficient polymerization, insufficient thickening of the raw material mixture, and the escape of air bubbles from the raw material mixture.

[0110] (6) In all of Examples 1 to 7, the hardness was 35 or less, the rebound resilience was 35% or more, and the compression set (50% compression) was 20% or less. However, cell roughness occurred in Example 1. This is thought to be due to the fact that the amount of polyol B, which has a high EO content, added was somewhat large, destabilizing foam formation. (7) In Example 6, compared to Example 2, the hardness was lower, the rebound resilience was increased, and the compression set was lower. This is thought to be due to the fact that the increased amount of polyol B improved breathability and the flexibility of the molecular skeleton.

[0111]

[0112]

[0113] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the present invention.

[0114] The polyurethane foam according to the present invention can be used for apparel, sporting goods, toys, bedding, interior goods, and the like.

Claims

1. a compound having an active hydrogen atom; and a polyisocyanate, and The compound having an active hydrogen atom is More than 40.0 mass% of polyol A; Polyol B in an amount of more than 0 mass%; and monool C of more than 0 mass% and less than 15.0 mass%; The rebound resilience is 35% or more. Polyurethane foam. however, The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 4,500 or more and an EO content of less than 50.0 mass%. The "polyol B" refers to one or more polyether polyols having an EO content of 50.0 mass% or more, The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more, "mass%" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C to the total mass of the compound having an active hydrogen atom, The "rebound resilience" refers to a value measured in accordance with JIS K6255.

2. Asker F hardness is 35 or less. The polyurethane foam according to claim 1.

3. The compression set is 20% or less. The polyurethane foam according to claim 1. The "compression set" refers to a value measured in accordance with JIS K6400-3 (50% compression).

4. As raw materials, monool C having a weight average molecular weight of 2000 or more, A silicone-based foam stabilizer is used, The rebound resilience is 35% or more, Asker F hardness is 23 or more and 35 or less. Polyurethane foam. The "rebound resilience" mentioned above refers to a value measured in accordance with JIS K6255.

5. A compound having an active hydrogen atom, and a polyisocyanate, and The compound having an active hydrogen atom is More than 40.0 mass% of polyol A; Polyol B having more than 0 mass% and not more than 20 mass%; and monool C of more than 0 mass% and less than 15.0 mass%; The rebound resilience is 35% or more. Polyurethane foam. however, The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 3,000 or more and an EO content of less than 50.0 mass%, The "polyol B" refers to one or more polyether polyols having a weight average molecular weight of 3,400 or less and an EO content of 50.0 mass% or more, The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more, "mass%" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C to the total mass of the compound having an active hydrogen atom, The "rebound resilience" refers to a value measured in accordance with JIS K6255.

6. A compound having an active hydrogen atom, and a polyisocyanate, and The compound having an active hydrogen atom is 70.0 mass% or more of polyol A; Polyol B in an amount of more than 0 mass%; and monool C of more than 0 mass% and less than 15.0 mass%; Polyurethane foam. however, The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 4,500 or more and 9,000 or less and an EO content of less than 50.0 mass%. The "polyol B" refers to one or more polyether polyols having an EO content of 50.0 mass% or more, The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more, The "mass %" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C to the total mass of the compound having an active hydrogen atom, respectively.

7. A compound having an active hydrogen atom; and a polyisocyanate, and The compound having an active hydrogen atom is 70.0 mass% or more of polyol A; Polyol B in an amount of more than 0 mass%; and monool C of more than 0 mass% and less than 15.0 mass%; Asker F hardness is 35 or less. Polyurethane foam. however, The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 4,500 or more and an EO content of less than 50.0 mass%. The "polyol B" refers to one or more polyether polyols having an EO content of 50.0 mass% or more, The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more, The "mass %" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C to the total mass of the compound having an active hydrogen atom, respectively.

8. A method for producing a polyolefin copolymer using a monool C having a weight average molecular weight of 2000 or more and an EO content of 0 mass% as a raw material, The rebound resilience is 35% or more, Asker F hardness is 35 or less. Polyurethane foam. The "rebound resilience" mentioned above refers to a value measured in accordance with JIS K6255.

9. A compound having an active hydrogen atom; and a polyisocyanate, and The compound having an active hydrogen atom is More than 40.0 mass% of polyol A; Polyol B in an amount of more than 0 mass%; and monool C of more than 0 mass% and less than 15.0 mass%; The rebound resilience is 35% or more. Polyurethane foam. however, The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 3,000 or more and an EO content of 20.0 mass% or less, The "polyol B" refers to one or more polyether polyols having an EO content of 50.0 mass% or more, The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more, "mass%" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C to the total mass of the compound having an active hydrogen atom, The "rebound resilience" refers to a value measured in accordance with JIS K6255.

10. A compound having an active hydrogen atom, and a polyisocyanate, and The compound having an active hydrogen atom is More than 40.0 mass% of polyol A; Polyol B in an amount of more than 0 mass%; and monool C of more than 0 mass% and less than 15.0 mass%; The rebound resilience is 35% or more. Polyurethane foam. however, The "polyol A" refers to one or more polyether polyols having a weight average molecular weight of 3,000 or more and an EO content of less than 50.0 mass%, The "polyol B" refers to one or more polyether polyols having an EO content of 50.0 mass% or more, The "monool C" refers to one or more monools having a weight average molecular weight of 2000 or more and an EO content of 0 mass %, "mass%" representing the content of the polyol A, the polyol B, or the monool C refers to the ratio of the mass of the polyol A, the polyol B, or the monool C to the total mass of the compound having an active hydrogen atom, The "rebound resilience" refers to a value measured in accordance with JIS K6255.