Polyurethane foam and cushioning material

Abstract

In a polyurethane foam using a polyol as a starting material, the polyol includes a castor oil-based polyol, and the total EO content of the polyol is 10.0 mass% or less. The Gurley air permeability of the polyurethane foam is preferably 3.0 seconds or more. It is preferable that the polyurethane foam has a compressive residual strain at 100 DEG C of 10.0% or less. A cushioning material is used around a battery comprising such a polyurethane foam.

Description

Technical Field

[0001] The present invention relates to a polyurethane foam and a cushioning material, and more particularly to a polyurethane foam having high heat resistance and low air permeability and a cushioning material comprising the polyurethane foam. Background Art

[0002] Polyurethane refers to a polymer 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. Therefore, polyurethane is used in various automotive parts, synthetic leather, coatings, adhesives, etc. In addition, polyurethane foam, which is formed by foaming polyurethane, is used in thermal insulation materials, cushioning materials, etc.

[0003] As one of methods for producing polyurethane foam, there is known a method of forcibly mixing an inert gas into a polyurethane raw material containing a polyol component, a polyisocyanate component, etc. to form cells (mechanical foaming method).

[0004] Various proposals have been made regarding such polyurethane foams.

[0005] For example, Patent Document 1 discloses a polyurethane foam obtained by foaming and reacting a raw material mixture containing the following components using a mechanical foaming method:

[0006] (a) 56 parts by weight of polyether polyol B having 3 functional groups, a number average molecular weight of 3300, and an EO ratio of 70 mol %;

[0007] (b) 1:44 parts by weight of a castor oil-based polyol having a functional group number of 2.7 and a number average molecular weight of 950 (hydroxyl value of 160 mgKOH / g); and

[0008] (c) 1,4-Butanediol (crosslinking agent): 11 parts by weight.

[0009] This document describes that a polyurethane foam having a compressive residual strain of 20% or less at 100° C. can be obtained by this method.

[0010] Patent Document 2 discloses a polyurethane foam obtained by foaming and reacting a raw material mixture containing the following components using a mechanical foaming method:

[0011] (a) polyether polyol (Sannix GP-600, manufactured by Sanyo Chemical Industries, Ltd.): 60 parts by weight;

[0012] (b) castor oil-based polyol (manufactured by Ito Oil Products Co., Ltd., URIC Y-406): 40 parts by weight;

[0013] (c) light calcium carbonate: 40 parts by weight; and

[0014] (d) Hydrophobic silica: 1 part by weight.

[0015] The document states as follows:

[0016] (A) When the raw material contains hydrophobic silica, in addition to the foaming effect as a nucleating agent, it also improves the foam stability and has good foam retention.

[0017] (B) When the content of light calcium carbonate is optimized, higher impact absorption is exhibited.

[0018] Patent Document 3 discloses a polyurethane foam obtained by foaming and reacting a raw material mixture containing the following components using a mechanical foaming method:

[0019] (a) 63 parts of a polyether polyol having a hydroxyl value of 37 mgKOH / g and a functional group number of 3 (Sannix-FA-951, manufactured by Sanyo Chemical Industries, Ltd.); and

[0020] (b) Castor oil-modified polyol having a hydroxyl value of 90 mgKOH / g and a functional group number of 3 (URIC H-57 manufactured by Ito Oil Products Co., Ltd.): 63 parts.

[0021] This document describes that this method can reduce the hardness and compression set of polyurethane foam.

[0022] Polyurethane foams showing rubber elasticity can be used as, for example

[0023] (a) Cushioning materials around batteries and electronic control units of electric vehicles;

[0024] (b) Cushioning materials around stationary batteries;

[0025] (c) Sealing materials for sealing parts of solar cells, etc. Since the interior of electric vehicles, stationary batteries, or solar cells may be exposed to high temperatures, polyurethane foams used in such applications are required to have heat resistance.

[0026] Furthermore, when assembling various devices containing such polyurethane foam, parts made of polyurethane foam are sucked by an automatic suction machine and transported to a predetermined location. Therefore, polyurethane foam used in such applications is required to have low air permeability to a degree that allows it to be sucked by the automatic suction machine.

[0027] However, there has never been an example of a polyurethane foam that combines high heat resistance with low air permeability.

[0028] Prior art literature

[0029] Patent Literature

[0030] Patent Document 1: Japanese Patent No. 5905464

[0031] Patent Document 2: Japanese Patent Application Publication No. 2020-084173

[0032] Patent Document 3: Japanese Patent Application Laid-Open No. 2008-280447 Summary of the Invention

[0033] Problems to be solved by the invention

[0034] The problem to be solved by the present invention is to provide a novel polyurethane foam having both high heat resistance and low air permeability.

[0035] Means of solving problems

[0036] In order to solve the above problems, the present invention

[0037] In polyurethane foam made from polyols,

[0038] The polyol comprises a castor oil-based polyol,

[0039] The total ethylene oxide (EO) content of the polyol is 10.0 mass % or less.

[0040] Effects of the Invention

[0041] When reacting a raw material mixture containing a polyol, a polyisocyanate, a foam stabilizer, a catalyst, and a foaming gas, using a castor oil-based polyol as the polyol yields a polyurethane foam with higher heat resistance than when using only a polyether polyol. This is presumably because castor oil-based polyols contain ester bonds, which have higher thermal stability than ether bonds.

[0042] Furthermore, using a polyol with a low total EO content as the polyol can produce a polyurethane foam with low air permeability. This is presumably because lowering the total EO content of the polyol improves the compatibility of the raw materials and suppresses excessive interconnection of cells. DETAILED DESCRIPTION

[0043] Hereinafter, one embodiment of the present invention will be described in detail.

[0044] [1. Polyurethane foam]

[0045] The polyurethane foam according to the present invention is obtained by reacting a raw material mixture containing a polyol (more specifically, a raw material mixture containing a polyol, a polyisocyanate, a foam stabilizer, a catalyst, and a foaming gas).

[0046] [1.1. Polyols]

[0047] [1.1.1. Materials]

[0048] Polyol is one of the main raw materials used in the manufacture of polyurethane foam.

[0049] In the present invention, the polyol contains at least castor oil-based polyol. In addition to castor oil-based polyol, the polyol preferably further contains polyether polyol and low molecular weight polyol. In addition to these, the polyol may also contain polymer polyol.

[0050] [A. Castor Oil-Based Polyol]

[0051] "Castor oil-based polyol" is a type of polyester polyol and refers to castor oil or its modified products.

[0052] In the present invention, castor oil-based polyols are preferably:

[0053] (a) a hydroxyl value of 50 mgKOH / g or more and 300 mgKOH / g or less;

[0054] (b) the number of functional groups is 2.0 or more and 3.0 or less;

[0055] (c) The EO content is less than 20.0 mass%.

[0056] If the hydroxyl value is too low, the number of reactive sites may decrease, leading to poor hardness and worsening of compressive residual strain. Therefore, the hydroxyl value is preferably 50 mgKOH / g or higher. More preferably, the hydroxyl value is 100 mgKOH / g or higher, or 150 mgKOH / g or higher.

[0057] On the other hand, if the hydroxyl value is too high, the polyurethane foam may become too hard. Therefore, the hydroxyl value is preferably 300 mgKOH / g or less. The hydroxyl value is more preferably 250 mgKOH / g or less, or 225 mgKOH / g or less.

[0058] Generally, the more functional groups a castor oil-based polyol has, the more crosslinking points it has, thus improving the heat resistance of the polyurethane foam. To achieve this effect, the number of functional groups is preferably 2.0 or greater, and preferably 2.5 or greater.

[0059] On the other hand, if the number of functional groups is too large, the polyurethane foam may become too hard. Therefore, the number of functional groups is preferably 3.0 or less, and more preferably 2.7 or less.

[0060] The “EO content (mass %) of castor oil-based polyol” refers to the ratio of the mass of ethylene oxide units contained in the castor oil-based polyol to the total mass of alkylene oxide units contained in the castor oil-based polyol.

[0061] When using castor oil-based polyols with a high EO content as a raw material for polyurethane foam, the compatibility of the raw materials may decrease, resulting in excessive interconnected bubbles and increased air permeability of the polyurethane foam. Therefore, the EO content is preferably less than 20.0 mass%. More preferably, the EO content is 10.0 mass% or less, 5.0 mass% or less, 3.0 mass% or less, or 1.0 mass% or less.

[0062] [B. Polyether polyol]

[0063] The "polyether polyol" refers to a polyol obtained by addition polymerization of an alkylene oxide and an initiator.

[0064] In the present invention, the polyether polyol is preferably:

[0065] (a) a hydroxyl value of 20 mgKOH / g or more and 800 mgKOH / g or less;

[0066] (b) the number of functional groups is 2.0 or more and 3.0 or less;

[0067] (c) The EO content is less than 20.0 mol%.

[0068] If the hydroxyl value is too low, the number of reactive sites may decrease, leading to poor hardness and worsening of compressive residual strain. Therefore, the hydroxyl value is preferably 20 mgKOH / g or higher. More preferably, the hydroxyl value is 30 mgKOH / g or higher, or 40 mgKOH or higher.

[0069] On the other hand, if the hydroxyl value is too high, the polyurethane foam may become too hard. Therefore, the hydroxyl value is preferably 800 mgKOH / g or less. The hydroxyl value is more preferably 600 mgKOH / g or less, or 400 mgKOH / g or less.

[0070] The number of functional groups may be 2.0 or more. Generally, the higher the number of functional groups of the polyether polyol, the higher the heat resistance of the polyurethane foam. The number of functional groups is more preferably 2.3 or more, or 2.5 or more.

[0071] On the other hand, if the number of functional groups is too large, the polyurethane foam may become too hard. Therefore, the number of functional groups is preferably 3.0 or less. The number of functional groups is more preferably 2.9 or less, or 2.8 or less.

[0072] The “EO content of the polyether polyol (mass %)” refers to the ratio of the mass of the ethylene oxide units contained in the polyether polyol to the total mass of the alkylene oxide units contained in the polyether polyol.

[0073] The EO content affects air permeability. Using castor oil-based polyols with high EO content as a raw material for polyurethane foam can reduce raw material compatibility, leading to excessive interconnected bubbles and increased air permeability. Therefore, the EO content is preferably less than 20.0 mass%. The EO content is preferably 10.0 mass% or less, 5.0 mass% or less, 3.0 mass% or less, or 1.0 mass% or less.

[0074] [C. Low molecular weight polyol]

[0075] In the present invention, the low molecular weight polyol is preferably:

[0076] (a) a hydroxyl value greater than 800 mgKOH / g;

[0077] (b) The number of functional groups is 2 or more.

[0078] If the hydroxyl value is too low, the number of reactive sites may decrease, leading to poor hardness and worsening of compressive residual strain. Therefore, the hydroxyl value is preferably greater than 800 mgKOH / g. More preferably, the hydroxyl value is greater than 830 mgKOH / g.

[0079] The number of functional groups may be at least 2.0 or more.

[0080] On the other hand, if the number of functional groups of the low molecular weight polyol is too large, the polyurethane foam may become too hard. Therefore, the number of functional groups is preferably 4 or less. The number of functional groups is more preferably 3 or less.

[0081] [D. Polymer polyol]

[0082] The "polymer polyol" refers to a polymer polyol obtained by dispersing polymer particles in a polyol such as polyether polyol. The polymer particles are obtained by polymerizing an ethylenically unsaturated monomer such as acrylonitrile or styrene.

[0083] In the present invention, the polymer polyol is preferably:

[0084] (a) a hydroxyl value of 20 mgKOH / g or more and 800 mgKOH / g or less;

[0085] (b) the number of functional groups is 2.0 or more and 3.0 or less;

[0086] (c) The EO content is less than 20.0 mol%.

[0087] If the hydroxyl value is too low, the number of reactive sites may decrease, leading to poor hardness and worsening of compressive residual strain. Therefore, the hydroxyl value is preferably 20 mgKOH / g or higher. More preferably, the hydroxyl value is 25 mgKOH / g or higher.

[0088] On the other hand, if the hydroxyl value is too high, the hardness of the polyurethane foam may become too high. Therefore, the hydroxyl value is preferably 800 mgKOH / g or less. The hydroxyl value is more preferably 600 mgKOH / g or less, or 400 mgKOH / g or less.

[0089] The number of functional groups may be at least 2.0, preferably 2.1 or more, or 2.5 or more.

[0090] On the other hand, if the number of functional groups is too large, the polyurethane foam may become too hard. Therefore, the number of functional groups is preferably 3.0 or less. The number of functional groups is more preferably 2.9 or less, or 2.8 or less.

[0091] The “EO content of the polymer polyol (mass %)” refers to the ratio of the mass of the ethylene oxide units contained in the polymer polyol to the total mass of the alkylene oxide units contained in the polymer polyol.

[0092] When using a polymer polyol as a raw material for polyurethane foam, if the EO content of the polymer polyol is too high, the compatibility of the raw materials may be reduced, resulting in excessive interconnectedness of the bubbles and increased air permeability of the polyurethane foam. Therefore, the EO content is preferably less than 20.0 mol%. More preferably, the EO content is 10.0 mass% or less, 5.0 mass% or less, 3.0 mass% or less, or 1.0 mass% or less.

[0093] [1.1.2. Polyol content]

[0094] [A. Content of castor oil-based polyol]

[0095] The “content of castor oil-based polyol (mass %)” refers to the ratio of the mass of castor oil-based polyol to the total mass of polyol.

[0096] If the content of castor oil-based polyol is too low, the heat resistance of the polyurethane foam may be reduced. Therefore, the content of castor oil-based polyol is preferably 20.0 mass% or more. More preferably, the content is 33.0 mass% or more, or 35.0 mass% or more.

[0097] On the other hand, if the castor oil-based polyol content is too high, the polyurethane foam may become too hard, even if the density of the polyurethane foam is low, and compression adhesion may be reduced. Therefore, the castor oil-based polyol content is preferably 80.0 mass% or less. It is more preferably 60.0 mass% or less, and even more preferably 50.0 mass% or less.

[0098] [B. Content of polyether polyol]

[0099] The “content of polyether polyol (mass %)” refers to the ratio of the mass of polyether polyol to the total mass of polyol.

[0100] If the polyether polyol content is too low, the flexibility of the polyurethane foam may be impaired, and the elongation may be reduced. Therefore, the polyether polyol content is preferably 20.0 mass% or more, and more preferably 30.0 mass% or more, or 40.0 mass% or more.

[0101] On the other hand, if the polyether polyol content is too high, the castor oil-based polyol content may become relatively low, potentially reducing the heat resistance of the polyurethane foam. Therefore, the polyether polyol content is preferably 65.0 mass% or less. More preferably, it is 60.0 mass% or less, or 55.0 mass% or less.

[0102] [C. Content of low molecular weight polyol]

[0103] The “content of low molecular weight polyol” refers to the ratio of the mass of the low molecular weight polyol to the total mass of the polyol.

[0104] If the content of the low molecular weight polyol is too low, the number of crosslinking points may become too small, and the heat resistance of the polyol may be reduced. Therefore, the content of the low molecular weight polyol is preferably 1.0 mass% or more.

[0105] On the other hand, if the content of the low molecular weight polyol is too high, the polyurethane foam may become too hard. Therefore, the content of the low molecular weight polyol is preferably 5.0 mass% or less. The content is more preferably 4.0 mass% or less, and even more preferably 3.0 mass% or less.

[0106] [D. Content of polymer polyol]

[0107] The "polymer polyol content (mass %)" refers to the ratio of the mass of the polymer polyol to the total mass of the polyol.

[0108] The raw material mixture may not contain a polymer polyol. However, if a polymer polyol is included in the raw material mixture, the rigidity of the polyurethane foam will be improved. To achieve this effect, the content of the polymer polyol is preferably 5.0 mass% or more.

[0109] On the other hand, if the polymer polyol content is too high, the castor oil-based polyol content may become relatively low, potentially reducing the heat resistance of the polyurethane foam. Therefore, the polymer polyol content is preferably 15.0 mass% or less. More preferably, it is 13.0 mass% or less, or 12.0 mass% or less.

[0110] [E.Total EO content]

[0111] The “total EO content (mass %)” refers to the ratio of the mass of the ethylene oxide units contained in the polyol to the total mass of the alkylene oxide units contained in the polyol.

[0112] If the total EO content of the polyols contained in the raw materials for polyurethane foam is too high, the compatibility of the raw materials may decrease, resulting in excessive interconnected cells and increased air permeability of the polyurethane foam. Therefore, the total EO content must be 10.0 mass% or less. The total EO content is preferably 5.0 mass% or less, 3.0 mass% or less, or 1.0 mass% or less.

[0113] [1.2. Polyisocyanate]

[0114] [1.2.1. Materials]

[0115] Polyisocyanate is another main raw material for making polyurethane foam. In the present invention, the type of polyisocyanate is not particularly limited. The raw material can contain one polyisocyanate, or it can contain two or more polyisocyanates.

[0116] Examples of polyisocyanates include:

[0117] (a) an aromatic isocyanate compound, an aliphatic isocyanate compound or an alicyclic isocyanate compound;

[0118] (b) Modified products of the above compounds, etc.

[0119] Examples of the aromatic isocyanate compound include:

[0120] Methylene diphenyl diisocyanate (MDI),

[0121] Crude diphenylmethane diisocyanate, toluene diisocyanate (TDI),

[0122] Naphthalene diisocyanate (NDI),

[0123] p-phenylene diisocyanate (PPDI), meta-phenylenediisocyanate (XDI),

[0124] Tetramethyl-m-xylylene diisocyanate (TMXDI),

[0125] dimethyl diphenyl diisocyanate (TODI), etc.

[0126] Examples of the aliphatic isocyanate compound include:

[0127] Hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI),

[0128] Lysine triisocyanate (LTI), etc.

[0129] Examples of the alicyclic isocyanate compound include:

[0130] Isophorone diisocyanate (IPDI),

[0131] Cyclohexane diisocyanate (CHDI), hydrogenated XDI (H6XDI),

[0132] Hydrogenated MDI (H 12 MDI) etc.

[0133] Examples of the modified isocyanate compound 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, oxazolidinone-modified isocyanate compounds, and isocyanate-terminated prepolymers.

[0134] Among them, the polyisocyanate is preferably an MDI-based isocyanate.

[0135] Here, "MDI-based isocyanate" refers to:

[0136] (a) MDI, a multinuclear form of MDI or a modified form of MDI, or

[0137] (b) A mixture of two or more selected from the group consisting of MDI, multinuclear forms of MDI, and modified forms of MDI.

[0138] If the reactivity of the polyisocyanate is too low, bubbles may escape from the raw material mixture before it cures, making it difficult to form foam. On the other hand, if the reactivity of the polyisocyanate is too high, the reaction may become too rapid, making it difficult to form by mechanical foaming.

[0139] In contrast, MDI-based isocyanate has moderate reactivity and therefore can easily produce foam with uniformly dispersed cells.

[0140] [1.2.2. Isocyanate index]

[0141] The “isocyanate index” refers to a value obtained by multiplying 100 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.

[0142] If the isocyanate index is too low, the number of crosslinking points may decrease, resulting in reduced heat resistance of the polyurethane foam. Therefore, the isocyanate index is preferably greater than 80. The isocyanate index is more preferably greater than 85, or greater than 90.

[0143] On the other hand, if the isocyanate index is too high, the number of crosslinking points may be excessive, and the polyurethane foam may become too hard. Therefore, the isocyanate index is preferably 120 or less. The isocyanate index is more preferably 115 or less, or 110 or less.

[0144] [1.3. Foam stabilizer]

[0145] [1.3.1. Materials]

[0146] The foam stabilizer is used to facilitate the dispersion of entrained gas during mechanical foaming of the raw material mixture, stabilize the bubbles, and adjust the bubble structure. In the present invention, the type of foam stabilizer is not particularly limited.

[0147] As foam stabilizers, there are, for example,

[0148] (a) silicone foam stabilizer;

[0149] (b) Fluorine-containing compound foam stabilizers;

[0150] (c) anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate;

[0151] (d) Phenolic compounds, etc.

[0152] The raw material mixture may contain any one of these foam stabilizers, or may contain two or more of them.

[0153] Among them, the foam stabilizer is preferably a silicone foam stabilizer, which is easier to control the degree of connectivity of bubbles than other foam stabilizers.

[0154] Specific examples of silicone foam stabilizers include

[0155] (a) Sulfonated ricinoleic acid sodium salt;

[0156] (b) a mixture of sulfonated ricinoleic acid sodium salt and a polysiloxane-polyoxyalkylene copolymer;

[0157] (c) dimethyl polysiloxane oil;

[0158] (d) Dimethylpolysiloxane oils in which some of the methyl groups are replaced by organic functional groups.

[0159] [1.3.2. Content]

[0160] The “content of the foam stabilizer” refers to the total mass of the foam stabilizer when the mass of the polyol is set to 100.

[0161] If the content of the foam stabilizer is too low, foam formation may be difficult. Therefore, the content of the foam stabilizer is preferably 3.0 parts by mass or more. More preferably, the content is 4.0 parts by mass or more, or 5.0 parts by mass or more.

[0162] On the other hand, even if more than the necessary amount of foam stabilizer is added, the effect is not different and there is no practical benefit. Therefore, the content of the foam stabilizer is preferably 30.0 parts by mass or less. More preferably, the content is 15.0 parts by mass or less, or 10.0 parts by mass or less.

[0163] [1.4. Catalyst]

[0164] [1.4.1. Materials]

[0165] The catalyst is used to promote the resinification reaction. In the present invention, the type of catalyst is not particularly limited. Examples of the catalyst include:

[0166] (a) Fe-based catalysts such as iron acetylacetonate;

[0167] (b) Ni-based catalysts such as nickel acetylacetonate, nickel octoate, and nickel naphthenate;

[0168] (c) Sn-based catalysts such as stannous octoate and dibutyltin dilaurate; and

[0169] (d) Pb-based catalysts such as lead octoate.

[0170] The raw material mixture may contain any one of these catalysts, or may contain two or more of them.

[0171] [1.4.2. Content]

[0172] The “catalyst content” refers to the total mass of the catalyst when the mass of the polyol is set to 100.

[0173] Generally, the higher the catalyst content, the faster the resinification reaction can proceed. To achieve this effect, the catalyst content is preferably 0.001 parts by mass or more. More preferably, the content is 0.005 parts by mass or more, or 0.01 parts by mass or more.

[0174] On the other hand, if the catalyst content is excessive, the polyurethane foam may become too hard. Therefore, the catalyst content is preferably 1.0 part by mass or less. More preferably, the content is 0.04 part by mass or less, or 0.02 part by mass or less.

[0175] [1.5. Foaming gas]

[0176] [1.5.1. Materials]

[0177] The foaming gas is not particularly limited as long as it does not adversely affect the reaction between the polyol and the polyisocyanate.

[0178] Examples of the foaming gas include:

[0179] (a) Dry air:

[0180] (b) Inert gases such as nitrogen, etc.

[0181] [1.5.2. Content]

[0182] The “content of the foaming gas” refers to the volume of the foaming gas when the volume of the raw material after removing the foaming gas is set to 100.

[0183] If the content of the foaming gas is too low, foaming may be insufficient. Therefore, the content of the foaming gas is preferably 10 parts by volume or more. More preferably, the content is 40 parts by volume or more, or 50 parts by volume or more.

[0184] On the other hand, if the content of the foaming gas is excessive, bubble breakage and coalescence are likely to occur in the foamed liquid. Therefore, the content of the foaming gas is preferably 95 parts by volume or less. More preferably, the content is 85 parts by volume or less, or 75 parts by volume or less.

[0185] [1.6. Other ingredients]

[0186] The raw material mixture for producing polyurethane foam may contain the following components in addition to the above components. The amount of each component added is not particularly limited, and it is preferred to select the most appropriate amount according to the purpose.

[0187] [1.6.1. Water absorbent]

[0188] The raw material mixture may contain a desiccant. This desiccant is used to remove moisture from the raw material mixture and inhibit the reaction between the polyisocyanate and the moisture. When the polyisocyanate reacts with moisture, CO2 gas is generated, making it difficult to control the bubbles. In the present invention, the type of desiccant is not particularly limited.

[0189] Examples of the water-absorbing agent include molecular sieves, synthetic zeolite, silica powder, alumina powder, lithium hydroxide powder, and barium hydroxide powder.

[0190] [1.6.2. Antioxidants]

[0191] The raw material mixture may contain an antioxidant. The antioxidant is used to suppress degradation of the polyurethane due to oxidation. In the present invention, the type of antioxidant is not particularly limited.

[0192] Examples of the antioxidant include hindered phenol-based antioxidants, amine-based antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants.

[0193] [1.6.3. Filler]

[0194] The raw material mixture may contain fillers. Fillers are used to increase the volume of the polyurethane foam, reduce the amount of polyurethane raw materials used per unit volume, and reduce the cost of the polyurethane foam. In the present invention, the type of filler is not particularly limited.

[0195] Examples of the filler include aluminum hydroxide, calcium carbonate, talc, and clay.

[0196] [1.6.4. Foam retaining agent]

[0197] The raw material mixture may contain a foam-retaining agent. This foam-retaining agent is used to increase the viscosity of the raw material mixture and inhibit the release of bubbles from the raw material mixture before it solidifies. In the present invention, the type of foam-retaining agent is not particularly limited as long as it can be uniformly dispersed in the polyol. Examples of foam-retaining agents include hydrophobic silica.

[0198] [1.6.5. Colorants]

[0199] The raw material mixture may contain a colorant. The colorant is used to color the polyurethane foam into a desired color. In the present invention, the type of the colorant is not particularly limited.

[0200] Examples of the colorant include carbon black, titanium oxide, mineral pigments, organic pigments, and dyes.

[0201] [1.7. Reaction of the raw material mixture]

[0202] The polyurethane foam involved in the present invention is produced using a mechanical foaming method. "Mechanical foaming method" refers to the following method:

[0203] (a) using a high shear mixer, mixing the raw material mixture while blowing an inert gas, thereby forming a foaming raw material composition containing fine bubbles;

[0204] (b) applying the foaming raw material mixture on the surface of a substrate (e.g., a PET film);

[0205] (c) The coating film is heated to a predetermined temperature to cure it.

[0206] In the present invention, the reaction conditions of the raw material mixture are not particularly limited, and the most appropriate conditions can be selected according to the purpose.

[0207] [1.8. Features]

[0208] [1.8.1. Gurley air permeability]

[0209] The "Gurley air permeability" refers to a value measured in accordance with JIS P 8117:2009.

[0210] Due to the optimization of the types and contents of various raw materials, the polyurethane foam of the present invention exhibits low air permeability. When the manufacturing conditions are optimized, the Gurley air permeability is 3.0 seconds or greater. Further optimization of the manufacturing conditions can achieve Gurley air permeability of 4.0 seconds or greater, 10.0 seconds or greater, 50.0 seconds or greater, or 100.0 seconds or greater.

[0211] [1.8.2. Compressive residual strain]

[0212] The “compressive residual strain” refers to a value measured in accordance with JIS K 6401:2011.

[0213] The polyurethane foam of the present invention exhibits high heat resistance due to optimized raw material types and contents. Optimized manufacturing conditions result in a compressive residual strain of 10.0% or less at 100°C. Further optimization of manufacturing conditions results in a compressive residual strain of 9.0%, 8.0%, or 7.0% or less at 100°C.

[0214] [1.8.3. Density]

[0215] "Density" refers to a value measured in accordance with JIS K 6401:2011.

[0216] The polyurethane foam of the present invention can control the density within a relatively wide range by controlling the expansion ratio. If the manufacturing conditions are optimized, a density of 50 kg / m 3 Above and 900kg / m 3The density is preferably 100 kg / m 3 Above and 600kg / m 3 Below, or 150kg / m 3 Above and 500kg / m 3 the following.

[0217] [1.9. Purpose]

[0218] The polyurethane foam of the present invention can be used as

[0219] (a) Cushioning materials around batteries and electronic control units of electric vehicles;

[0220] (b) Cushioning materials around stationary batteries;

[0221] (c) Sealing materials for sealing portions of solar cells, etc.

[0222] The polyurethane foam of the present invention is suitable as a buffer material around batteries.

[0223] [2. Function]

[0224] When reacting a raw material mixture containing a polyol, a polyisocyanate, a foam stabilizer, a catalyst, and a foaming gas, using a castor oil-based polyol as the polyol yields a polyurethane foam with higher heat resistance than when using only a polyether polyol. This is presumably because castor oil-based polyols contain ester bonds, which have higher thermal stability than ether bonds.

[0225] Furthermore, using a polyol with a low total EO content as the polyol can produce a polyurethane foam with low air permeability. This is presumably because reducing the total EO content in the polyol improves the compatibility of the raw materials and suppresses excessive interconnection of cells.

[0226] Example

[0227] (Examples 1 to 4, Comparative Examples 1 to 3)

[0228] [1. Preparation of Samples]

[0229] [1.1. Raw materials]

[0230] The following polyether polyols were used:

[0231] (1) Polyether polyol A:

[0232] Product name: Sannix (Registered Trademark) FA-103, manufactured by Sanyo Chemical Industries, Ltd.

[0233] (2) Polyether polyol B:

[0234] Product name: "Sannix (registered trademark) GP-600", manufactured by Sanyo Chemical Industries, Ltd.

[0235] (3) Polyether polyol C:

[0236] Product name: Primepol (Registered Trademark) FF-3320, manufactured by Sanyo Chemical Industries, Ltd.

[0237] (4) Polyether polyol D:

[0238] Product name: "Sannix (registered trademark) PP-2000", manufactured by Sanyo Chemical Industries, Ltd.

[0239] (5) Polyether polyol E:

[0240] Product name: "Sannix (registered trademark) PP-400", manufactured by Sanyo Chemical Industries, Ltd.

[0241] The following polyester polyols were used:

[0242] (1) Polyester polyol A (castor oil-based polyol):

[0243] Product name: "Deodorized purified castor oil," manufactured by Toyokuni Oil Co., Ltd.

[0244] (2) Polyester polyol B (castor oil-based polyol):

[0245] Product name: URIC AC-009, manufactured by Ito Oil Manufacturing Co., Ltd.

[0246] (3) Polyester polyol C (polycaprolactone diol):

[0247] Product name: PLACCEL 205U, manufactured by Daicel Corporation

[0248] (4) Polyester polyol D (adipate):

[0249] The product name is "ADEKA New Ace (アデカニューエース) (registered trademark) Y65-55", manufactured by ADEKA Co., Ltd.

[0250] The following polymer polyols were used:

[0251] (1) Polymer polyol A:

[0252] Product name: EXCENOL (registered trademark) 913, manufactured by AGC Corporation

[0253] (2) Polymer polyol B:

[0254] Product name: EXCENOL (registered trademark) 914, manufactured by AGC Corporation

[0255] The following low molecular weight polyols were used:

[0256] (1) Low molecular weight polyol A: dipropylene glycol, manufactured by AGC Corporation

[0257] (2) Low molecular weight polyol B: 2-methyl-1,3-propanediol, manufactured by AGC Corporation.

[0258] The following water absorbents and antioxidants were used, respectively.

[0259] (1) Moisture absorbent: Product name: Molsiv Adsorbents 3A Powder, manufactured by UOP LLC

[0260] (2) Antioxidant (hindered phenol type): Product name: "SONGNOX 1135 LQ / IRGANOX", manufactured by Songwon Industrial Co., Ltd. / BASF Japan Ltd.

[0261] The following fillers were used:

[0262] (1) Filler A (aluminum hydroxide): Product name: "HIGILITE (ハイジライト) (registered trademark) H-21 / aluminum hydroxide", manufactured by Showa Denko K.K. / Almorix Co., Ltd.

[0263] (2) Filler B (aluminum hydroxide): Product name "Aluminum Hydroxide C-31", manufactured by Sumitomo Chemical Co., Ltd.

[0264] (3) Filler C (calcium carbonate): product name: "SILVER W", manufactured by Shiraishi Calcium Co., Ltd.

[0265] The following foam retainers and foam stabilizers were used:

[0266] (1) Foam retaining agent (hydrophobic silica): Product name "SS-80K", manufactured by TOSOH SILICA Co., Ltd.

[0267] (2) Foam stabilizer A: product name “VORASURF (registered trademark) SZ-1952 Additive”, manufactured by Dow Toray Industries, Ltd.

[0268] (3) Foam stabilizer B: Product name "SZ-1968", manufactured by Dow Toray Industries, Ltd.

[0269] (4) Foam stabilizer C: Product name "SZ-1718", manufactured by Dow Toray Industries, Ltd.

[0270] The following catalysts were used:

[0271] (1) Catalyst A (Fe-based catalyst): Product name "FIN-PA1 / LT CAT", manufactured by Nippon Chemical Industry Co., Ltd. / PAN Chemical, catalyst component content 0.25 mass%

[0272] (2) Catalyst B (Ni-based catalyst): Product name: NIAX CATALYST LC-5615, manufactured by Momentive Performance Materials Japan Co., Ltd., catalyst component content: 15.0 mass%

[0273] The following polyisocyanates were used:

[0274] (1) Polyisocyanate A (crude MDI): NCO group content 31.5%, product name "LUPRANATE (registered trademark) M5S Ex Korea", manufactured by BASF Japan

[0275] (2) Polyisocyanate B (pure MDI): NCO group content 33.57%, product name “Foamlite (フォームライト) (registered trademark) MI”, manufactured by BASF INOAC POLYURETHANES Co., Ltd.

[0276] (3) Polyisocyanate C (carbodiimide-modified MDI): NCO group content 30.88%, product name "Millionate MTL-S", manufactured by Tosoh Corporation

[0277] The above raw materials are mixed in the prescribed proportions. This mixture is fed into a mixing head and stirred until uniform while inert gas (nitrogen) is added, resulting in a foaming mixture containing fine bubbles. The foaming mixture is then coated onto a PET film and heat-cured at 200°C.

[0278] [2. Test methods]

[0279] [2.1.Thickness]

[0280] The thickness of the polyurethane foam was measured using a thickness gauge manufactured by Peacock.

[0281] [2.2. Density]

[0282] The density of polyurethane foam was measured in accordance with JIS K 6401:2011.

[0283] [2.3. Gurley air permeability]

[0284] The Gurley air permeability of polyurethane foam was measured in accordance with JIS P 8117: 2009. A sealed type (B type) tester was used.

[0285] [2.4. Compressive residual strain]

[0286] The compressive residual strain of the polyurethane foam was measured in accordance with JIS K 6401:2011.

[0287] Specifically, the polyurethane foam was held in a compressed state at a predetermined temperature for 22 hours. The compression rate was set to 50%, and the holding temperature was set to 70°C or 100°C. The compressive residual strain was calculated based on the thickness change before and after the holding.

[0288] [3. Results]

[0289] The results are shown in Table 1. It should be noted that Table 1 also shows the raw material composition of each sample. The numerical values ​​of the raw material composition represent parts by mass. In Table 1, "OHV" represents the hydroxyl value (mgKOH / g), "f" represents the number of functional groups, "MW" represents the molecular weight, and "EO rate" represents the EO content (mass %). Table 1 shows the following.

[0290] (1) The compressive residual strain at 100° C. in Comparative Example 1 exceeded 10.0%. This is probably because castor oil-based polyol was not used.

[0291] (2) The compressive residual strain at 100° C. in Comparative Example 2 exceeded 10.0%. This is probably because castor oil-based polyol was not used.

[0292] (3) The Gurley air permeability of Comparative Example 3 was 0.5 seconds. This is probably because the total EO content exceeded 10.0 mass%. (4) The Gurley air permeabilities of Examples 1 to 4 were all 3.0 seconds or more, and the compressive residual strain at 100°C was all 10.0% or less.

[0293] (5) In particular, the Gurley air permeabilities of Examples 2 to 4 were 100 seconds or more. This is probably because the total EO content was less than 4.0 mass%.

[0294] [Table 1]

[0295]

[0296] As mentioned above, although embodiment of this invention was demonstrated in detail, this invention is not limited to the said embodiment, Various changes are possible within the range which does not deviate from the summary of this invention.

[0297] Industrial applicability

[0298] The polyurethane foam of the present invention can be used as a cushioning material around batteries and electronic control units of electric vehicles, a cushioning material around stationary storage batteries, and a sealing material for sealing portions of solar cells.

Claims

1. A polyurethane foam, wherein In the polyurethane foam using polyol as raw material, The polyol comprises a castor oil-based polyol, The total EO content of the polyol is 10.0 mass % or less.

2. The polyurethane foam according to claim 1, wherein The Gurley air permeability is 3.0 seconds or more.

3. The polyurethane foam according to claim 1, wherein The compressive residual strain at 100°C is 10.0% or less.

4. A buffer material around a battery, wherein: The buffer material around the battery includes the polyurethane foam according to any one of claims 1 to 3.

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