Polyurethane foam

Abstract

We provide a novel low-rebound polyurethane foam. [Solution] The polyurethane foam is obtained from a composition of polyol, polyisocyanate, and paraffin. The polyurethane foam has a density (JIS K 7222:2005) of 60 kg / m³. 3 The above results indicate that the rebound elasticity (JIS K 6400-3:2011) is 15% or less.

Description

[Technical Field]

[0001] This disclosure relates to polyurethane foam. [Background technology]

[0002] Patent Document 1 discloses a flexible polyurethane foam using a polyol having an oxyethylene group. This flexible polyurethane foam is described as exhibiting excellent low rebound elasticity at room temperature and having good breathability.

[0003] Patent Document 2 discloses a low-rebound polyurethane foam using a polyisocyanate containing bis(isocyanatomethyl)cyclohexane. This low-rebound polyurethane foam is described as having excellent low rebound properties, as well as excellent discoloration resistance and excellent breathability. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2020 / 175324 [Patent Document 2] Japanese Patent Publication No. 2023-49486 [Overview of the project] [Problems that the invention aims to solve]

[0005] Low-rebound polyurethane foam generally has a low density. For applications such as cushioning, high-density low-rebound polyurethane foam is sometimes required to reduce the feeling of bottoming out. On the other hand, high-density low-rebound polyurethane foam presents the challenge of difficulty in ensuring breathability. This disclosure aims to solve at least one of the above-mentioned problems. This disclosure can be implemented in the following forms. [Means for solving the problem]

[0006] A polyol, a polyisocyanate, and paraffin, A polyurethane foam obtained from a composition obtained by mixing them, having a density (JIS K 7222:2005) of 60 kg / m 3 or more, and a resilience (JIS K 6400-3:2011) of 15% or less.

Effect of the Invention

[0007] The present disclosure can provide a novel low-resilience polyurethane foam capable of solving at least one of the above problems. For example, the present disclosure can provide a high-density low-resilience polyurethane foam with ensured ventilation.

Mode for Carrying Out the Invention

[0008] Here, desirable examples of the present disclosure are shown. [1] A polyurethane foam obtained from a composition obtained by mixing a polyol, a polyisocyanate, and paraffin, having a density (JIS K 7222:2005) of 60 kg / m or more, 3 and a resilience (JIS K 6400-3:2011) of 15% or less. [2] The polyurethane foam according to [1], having a hardness (JIS K 6400-2:2012 6.7 D method) of 150 N or more. [3] The polyurethane foam according to [1] or [2], wherein the polyol includes a polyester polyol.

[0009] ​Hereinafter, the present disclosure will be described in detail. In this specification, for a description using "-" for a numerical range, unless otherwise specified, it includes the lower limit value and the upper limit value. For example, in the description "10-20", both the lower limit value "10" and the upper limit value "20" are included. That is, "10-20" has the same meaning as "10 or more and 20 or less". Also, in this specification, the upper limit value and the lower limit value of each numerical range can be arbitrarily combined.

[0010] 1. Polyurethane foam The polyurethane foam is a polyurethane foam obtained from a composition in which a polyol, a polyisocyanate, and paraffin are mixed. The polyurethane foam has a density (JIS K 7222:2005) of 60 kg / m 3 or more and a resilience (JIS K 6400-3:2011) of 15% or less.

[0011] (1) Polyol The polyol is not particularly limited. Various polyols may be used alone or in combination of two or more. Examples of the polyol include polyether polyol, polyester polyol, polyether ester polyol, polycarbonate polyol, and a polyol having a carbon-carbon bond-based main chain. Examples of the polyether polyol include polyoxypropylene·polyoxyethylene polyol, polymer polyol, and polyoxytetramethylene glycol. Examples of the polyester polyol include aliphatic or aromatic polycondensation-based polyester polyol and polycaprolactone polyol. Examples of the polyol having a carbon-carbon bond-based main chain include polyolefin-based polyols such as polybutadiene polyol and isoprene polyol, and acrylic polyol.

[0012] (1.1) Polyether polyol Examples of polyether polyols include polyether polyols obtained by adding one or more of the following initiators (compounds) to one or more of the following: ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, epichlorohydrin, styrene oxide, etc., or polytetramethylene ether glycol.

[0013] (1.1.1) Initiator (1.1.1.1) Polyhydric alcohols and alkylene oxide adducts of polyhydric alcohols Examples of polyhydric alcohols: [Difunctional alcohols] Ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, trimethylene glycol [Trifunctional alcohols] Glycerin, Trimethylolpropane [4-functional alcohol] Pentaerythritol [6-functional alcohol] Sorbitol [8. Functional alcohols] Sucrose (1.1.1.2) Alkylene oxide adducts of polyhydric phenols Examples of alkylene oxide adducts of polyhydric phenols: alkylene oxide adducts of bisphenol A (1.1.1.3) Polyhydric hydroxy compounds Examples of polyhydric hydroxy compounds: phosphate, benzenephosphate, polyphosphate (e.g., tripolyphosphate and tetrapolyphosphate), etc. (1.1.1.4) Phenol-aniline-formaldehyde ternary condensation product (1.1.1.5) Aniline-formaldehyde condensation product (1.1.1.6) Polyamines Examples of polyamines: ethylenediamine, diethylenetriamine, triethylenetetramine, methylenebisorthochloraniline, 4,4- and 2,4'-diphenylmethanediamine, 2,4-tolylenediamine, 2,6-tolylenediamine, etc. (1.1.1.7) Alkanolamines Examples of alkanolamines: triethanolamine, diethanolamine, etc.

[0014] (1.1.2) Polymer polyols Polymer polyols are polyols obtained by graft polymerization of ethylenically unsaturated compounds such as acrylonitrile, styrene, and alkyl methacrylate onto the polyether polyols described above.

[0015] (1.2) Polyester polyol Polyester polyols are obtained by condensation of one or more compounds having at least two hydroxyl groups with one or more compounds having at least two carboxyl groups, or are ring-opening polymers of cyclic esters such as caprolactone and methylvalerolactone.

[0016] (1.2.1) Examples of compounds having at least two hydroxyl groups Ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, trimethylene glycol, 1,3- and 1,4-butanediol, tetramethylene glycol, neopentyl glycol, methylpentanediol, butylethylpropanediol, hexamethylene glycol, decamethylene glycol, glycerin, trimethylolpropane, pentaerythritol, sorbitol

[0017] (1.2.2) Examples of compounds having at least two carboxyl groups Malonic acid, maleic acid, succinic acid, adipic acid, tartaric acid, pimelic acid, azelaic acid, sebacic acid, oxalic acid, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, hemeltic acid

[0018] (1.3) Polycarbonate polyol Examples of polycarbonate polyols include those obtained by transesterification reactions between low molecular weight polyols such as butanediol and hexanediol and low molecular weight carbonates such as propylene carbonate and diethyl carbonate.

[0019] (1.4) Polyolefin-based polyols Examples of polyolefin-based polyols include polybutadiene polyols, polyisoprene polyols, hydrogenated polybutadiene polyols, and hydrogenated polyisoprene polyols.

[0020] (1.5) Plant-derived polyols In addition to the polyols mentioned above, plant-derived polyols may also be included as polyols. Examples of plant-derived polyols include castor oil polyols, soybean oil polyols, palm oil polyols, palm kernel oil polyols, coconut oil polyols, cashew oil polyols, olive oil polyols, cottonseed oil polyols, safflower oil polyols, sesame oil polyols, sunflower oil polyols, and linseed oil polyols. Plant-derived polyols typically have 2-3 hydroxyl functional groups per molecule. Examples of castor oil-based polyols include castor oil, reaction products of castor oil and polyols, and esterification reaction products of castor oil fatty acids and polyols. Examples of polyols to be reacted with castor oil or castor oil fatty acids include divalent polyols such as ethylene glycol, diethylene glycol, and propylene glycol, or trivalent or higher polyols such as glycerin, trimethylolpropane, hexanetriol, and sorbitol. Examples of soybean oil-based polyols include polyols derived from soybean oil, such as reaction products of soybean oil and polyols, and esterification reaction products of soybean oil fatty acids and polyols. The polyols used to react with soybean oil or soybean oil fatty acids can be the same as those used for castor oil. The same applies to palm oil-based polyols, cashew oil-based polyols, etc., as to soybean oil-based polyols. The various polyols exemplified as plant-derived polyols may be used individually or in combination of two or more.

[0021] (1.6) Preferred polyols The polyol preferably contains at least a polyester polyol, and more preferably contains a polyester polyol, a polyether polyol (a) with a weight-average molecular weight of less than 1000, and a polyether polyol (b) with a weight-average molecular weight of 1000 or more.

[0022] The weight-average molecular weight of the polyester polyol is preferably 400 to 3000, more preferably 600 to 2000, and even more preferably 800 to 1500. The number of functional groups in the polyester polyol is preferably 2 or more and 4 or less, more preferably 2 or 3, and even more preferably 2. The hydroxyl value of the polyester polyol is preferably 50 mg KOH / g or more and 200 mg KOH / g or less, more preferably 80 mg KOH / g or more and 170 mg KOH / g or less, and even more preferably 100 mg KOH / g or more and 140 mg KOH / g or less.

[0023] From the viewpoint of obtaining desired physical properties (hardness, resilience, etc.), the polyester polyol content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 13 parts by mass or more, when the total polyol content is 100 parts by mass. From the viewpoint of obtaining desired physical properties, the polyester polyol content is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less. From these viewpoints, the polyester polyol content is preferably 5 parts by mass or more and 40 parts by mass or less, more preferably 10 parts by mass or more and 30 parts by mass or less, and even more preferably 13 parts by mass or more and 25 parts by mass or less.

[0024] The weight-average molecular weight of polyether polyol (a) is less than 1000, preferably between 400 and 900, and more preferably between 600 and 800. The number of functional groups in polyether polyol (a) is preferably 2 to 5, more preferably 2 to 4, and even more preferably 3. The hydroxyl value of polyether polyol (a) is preferably 100 mg KOH / g or more and 350 mg KOH / g or less, more preferably 150 mg KOH / g or more and 300 mg KOH / g or less, and even more preferably 200 mg KOH / g or more and 250 mg KOH / g or less.

[0025] From the viewpoint of obtaining desired physical properties, the content of polyether polyol (a) is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 60 parts by mass or more, when the total polyol is 100 parts by mass. From the viewpoint of obtaining desired physical properties, the content of the above polyether polyol (a) is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and even more preferably 70 parts by mass or less. From these viewpoints, the content of the above polyether polyol (a) is preferably 40 parts by mass or more and 80 parts by mass or less, more preferably 50 parts by mass or more and 75 parts by mass or less, and even more preferably 60 parts by mass or more and 70 parts by mass or less.

[0026] The weight-average molecular weight of polyether polyol (b) is 1000 or more, preferably 1500 to 10000, and more preferably 2000 to 5000. The number of functional groups in polyether polyol (b) is preferably 2 to 5, more preferably 2 to 4, and even more preferably 3. The hydroxyl value of polyether polyol (b) is preferably 100 mg KOH / g or more and 350 mg KOH / g or less, more preferably 150 mg KOH / g or more and 300 mg KOH / g or less, and even more preferably 200 mg KOH / g or more and 250 mg KOH / g or less.

[0027] The content of polyether polyol (b) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and even more preferably 13 parts by mass or more, when the total polyol is 100 parts by mass. The content of the above polyether polyol (b) is preferably 40 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 25 parts by mass or less, from the viewpoint of obtaining desired physical properties. From these viewpoints, the content of the above polyether polyol (b) is preferably 5 parts by mass or more and 40 parts by mass or less, more preferably 10 parts by mass or more and 30 parts by mass or less, and even more preferably 13 parts by mass or more and 25 parts by mass or less.

[0028] (2) Catalyst The polyurethane resin composition may contain a catalyst. Conventional known catalysts can be used without particular limitation. Various catalysts may be used individually or in combination of two or more. Amine catalysts and quaternary ammonium salt catalysts can be used as catalysts. Specific examples of these catalysts are shown below. Tertiary amine catalysts such as triethylenediamine, N,N-dimethylaminohexanol, triethylamine, tripropylamine, triisopropanolamine, tributylamine, trioctylamine, hexadecyldimethylamine, N-methylmorpholine, N-ethylmorpholine, N-octadecylmorpholine, monoethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N,N-dimethylethanolamine, N,N-dimethylaminoethoxyethoxyethanol, N,N-dimethylaminoethoxyethanol, formate and other salts of triethylenediamine, oxyalkylene adducts of amino groups of primary and secondary amines, aza ring compounds such as NN-dialkylpiperazines, various N,N',N'-trialkylaminoalkylhexahydrotriazines, and amine catalysts having an amino group as a functional group such as N,N,N",N"-tetramethyldiethylenetriamine can be used. Furthermore, quaternary ammonium salt catalysts such as tetraalkylammonium halides including tetramethylammonium chloride, tetraalkylammonium hydroxides including tetramethylammonium hydroxide, and tetraalkylammonium organic acid salts such as tetramethylammonium 2-ethylhexanoate, 2-hydroxypropyltrimethylammonium forate, and 2-hydroxypropyltrimethylammonium 2-ethylhexanoate can also be used. The total amount of one or more catalysts selected from the group consisting of amine catalysts and quaternary ammonium salt catalysts in the polyurethane resin composition is not particularly limited. From the viewpoint of sufficiently promoting the polyurethane formation reaction, the total amount of these catalysts is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and even more preferably 1 part by mass or more, per 100 parts by mass of polyol. From the viewpoint of maintaining the various physical properties of the polyurethane foam and from the viewpoint of manufacturing costs, the total amount of the above catalysts is preferably 5 parts by mass or less, more preferably 3.5 parts by mass or less, and even more preferably 2.5 parts by mass or less. From these viewpoints, the total amount of the above catalysts is preferably 0.1 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 3.5 parts by mass or less, and even more preferably 1 part by mass or more and 2.5 parts by mass or less.

[0029] A metal catalyst (organometallic catalyst) can be used as the catalyst. Any conventionally known metal catalyst can be used without any particular limitations. As metal catalysts, for example, metal salts of Sn (tin), Pb (lead), Bi (bismuth), Ni (nickel), Co (cobalt), Fe (iron), Zr (zirconium), Cu (copper), Zn (zinc), etc., as well as metal salts of organic acids, can be used. More specifically, the following metal catalysts can be used. Sn catalysts: Tin(II) octylate (2-ethylhexanoate tin, stanus dioctoate), tin(II) acetate, tin(II) octanoate, stanus dioleate, tin(II) neodecanoate, stanus dilaurate, dibutyltin oxide, dibutyltin diacetate, dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate, dibutyltin dimaleate, dioctyltin diacetate, etc. Pb catalysts: Lead octanoate, lead naphthenate, etc. Bi catalysts: Bismuth octylate, bismuth naphthenate, bismuth neodecanoate, bismuth rosinate, etc. Fe catalyst: Iron acetylacetonate, etc. Zr catalyst: Zirconium acetylacetonate, etc. Ni catalysts: Nickel acetylacetonate, nickel octylate, nickel naphthenate, etc. Co catalysts: Cobalt acetylacetonate, cobalt octylate, cobalt naphthenate, etc.

[0030] (3) Foam stabilizer The polyurethane resin composition may contain a foam stabilizer. The foam stabilizer is not particularly limited. Specifically, foam stabilizers include silicone compounds such as organopolysiloxanes, organopolysiloxane-polyoxyalkylene copolymers, polyalkenylsiloxanes having polyoxyalkylene side chains, and silicone-grease copolymers; anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate; polyethersiloxanes; and phenolic compounds. These foam stabilizers may be used individually or in combination of two or more. The amount of foam stabilizer added is not particularly limited. Preferably, the amount of foam stabilizer added is 0.03 parts by mass or more and 5 parts by mass or less per 100 parts by mass of polyol.

[0031] (4) Foaming agent The polyurethane resin composition may contain a blowing agent. The blowing agent is not particularly limited. Suitable blowing agents include water, pentane, cyclopentane, hexane, cyclohexane, dichloromethane, and carbon dioxide. When water is used as the blowing agent, the amount added is determined to obtain the desired density and good foaming state in the polyurethane foam, and is usually preferably 0.1 parts by mass or more and 10 parts by mass or less per 100 parts by mass of polyol.

[0032] (5) Polyisocyanates The polyisocyanate is not particularly limited. Preferably, at least one polyisocyanate selected from the group consisting of aromatic isocyanates, alicyclic isocyanates, and aliphatic isocyanates is used. A combination of one or more aliphatic isocyanates and one or more aromatic isocyanates is also possible. Furthermore, the polyisocyanate may be a bifunctional polyisocyanate having two isocyanate groups in one molecule, or a trifunctional or more polyisocyanate having three or more isocyanate groups in one molecule, and may be used alone or in combination of several. For example, difunctional polyisocyanates include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylenediisocyanate, p-phenylenediisocyanate, 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, xylylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylenediisocyanate, and 3,3'-dimethoxy-4,4'-biphenylenediisocyanate. Examples include aromatic isocyanates such as phenylenediisocyanate, alicyclic isocyanates such as cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, and methylcyclohexane diisocyanate, and aliphatic isocyanates such as butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylenediisocyanate, methylene diisocyanate, and lysine isocyanate. Examples of polyisocyanates with three or more functions include 1-methylbenzol-2,4,6-triisocyanate, 1,3,5-trimethylbenzol-2,4,6-triisocyanate, biphenyl-2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, 4,4'-dimethyldiphenylmethane-2,2',5,5'-tetraisocyanate, triphenylmethane-4,4',4"-triisocyanate, polymeric MDI, and the like. In addition, other urethane prepolymers, carbodiimide-modified isocyanates, isocyanurate-modified isocyanates, and biuret-modified isocyanates can also be used.

[0033] The mixing ratio of polyisocyanate and polyol is not particularly limited. The isocyanate index is preferably 80 to 120, more preferably 90 to 118, and even more preferably 100 to 115. The isocyanate index (INDEX) is the value obtained by multiplying the number of moles of isocyanate groups per mole of active hydrogen groups contained in the polyurethane resin composition by 100, and is calculated as [(Isocyanate equivalent in composition / Equivalent of active hydrogen in composition) × 100].

[0034] (6) Paraffin Paraffin typically refers to alkanes (chain-type saturated hydrocarbons) with 15 or more carbon atoms. Paraffin may be linear or branched, but it is preferable that it be mainly composed of linear saturated hydrocarbons. The main component refers to the component that makes up the paraffin in the largest proportion.

[0035] Paraffin may be liquid paraffin or paraffin wax. Liquid paraffin mainly contains saturated aliphatic hydrocarbons with 15 to 35 carbon atoms and is liquid at room temperature (e.g., 15°C-25°C). Paraffin wax mainly contains saturated aliphatic hydrocarbons with 20 to 50 carbon atoms and is solid at room temperature. Paraffin may be used alone or in combination with other materials.

[0036] Liquid paraffin is particularly preferably used as specified in JIS K2231:1993. The average molecular weight of liquid paraffin is not particularly limited. Preferably, the average molecular weight of liquid paraffin is between 300 and 500. The average molecular weight of liquid paraffin can be calculated using gas chromatography and normal paraffin as a standard substance, from a calibration curve obtained using normal paraffin.

[0037] Paraffin can be produced by conventional organic reactions, or it can be used as a commercially available product. Commercially available paraffin products include: "No.350-S" (manufactured by Sanko Chemical Industry Co., Ltd.), "No.70-S" (manufactured by Sanko Chemical Industry Co., Ltd.), "Moresco White P-40", "Moresco White P-55", "Moresco White P-60", "Moresco White P-70", "Moresco White P-80", "Moresco White P-100", "Moresco White P-120", "Moresco White P-150", "Moresco White P-200", "Moresco White P-260", "Moresco White P-350" (all manufactured by MORESCO Corporation), "Hydrocarbon Liquid Paraffin" (manufactured by Wako Pure Chemical Industries, Ltd.), "Paraffin mp 42℃~44℃", "Paraffin mp 48℃~50℃", "Paraffin mp 50℃~52℃", "Paraffin mp 52℃~54℃", "Paraffin mp 54℃~56℃", "Paraffin mp 56℃~58℃", "Paraffin Examples include "mp58℃~60℃", "Paraffin mp60℃~62℃" (both manufactured by Kanto Chemical Co., Ltd.), "FNP-0090", "FNP-0080", "PARAFFIN WAX-120", "PARAFFIN WAX-115", and "PARAFFIN WAX-150" (all manufactured by Nippon Seiro Co., Ltd.).

[0038] The amount of paraffin is not particularly limited. From the viewpoint of ensuring breathability of the polyurethane foam, the amount of paraffin is preferably 0.5 parts by mass or more, more preferably 2 parts by mass or more, and even more preferably 3 parts by mass or more, per 100 parts by mass of polyol. From the viewpoint of moldability of the polyurethane foam, the amount of paraffin is preferably 16 parts by mass or less, more preferably 12 parts by mass or less, and even more preferably 10 parts by mass or less. From these viewpoints, the amount of paraffin is preferably 0.5 parts by mass or more and 16 parts by mass or less, more preferably 2 parts by mass or more and 12 parts by mass or less, and even more preferably 3 parts by mass or more and 10 parts by mass or less. When two or more types of paraffin are used, the above amounts refer to the total amount of all paraffin.

[0039] (7) Other additives Other additives such as crosslinking agents, plasticizers, flame retardants, fillers, antioxidants, ultraviolet absorbers, defoaming agents, compatibilizers, colorants, stabilizers, antibacterial agents, fungicides, deodorants, odor eliminators, fragrances, and flavoring agents can be appropriately incorporated into the polyurethane resin composition. Examples of crosslinking agents include short-chain diol-based crosslinking agents such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, glycerin, and trimethylolpropane. Examples of colorants include pigments, dyes, and colorants.

[0040] (8) Physical properties of the polyurethane foam The physical properties of the polyurethane foam can be appropriately set according to the intended use and other factors. The polyurethane foam is preferably a flexible polyurethane foam. The polyurethane foam preferably has the following physical properties. (8.1) Density (apparent density) The density (JIS K7222:2005) is 60 kg / m 3 or more, and depending on the intended use and other factors, it can be 70 kg / m 3 or more, 80 kg / m 3 or more, 90 kg / m 3 or more, 100 kg / m 3 or more, 110 kg / m 3 or more, 120 kg / m 3 or more. The upper limit of the density is not particularly limited, and for example, it can be 200 kg / m 3 or less, 150 kg / m 3 or less, 110 kg / m 3 or less. (8.2) Resilience The resilience (JIS K6400-3:2011) is 15% or less, and depending on the intended use and other factors, it can be 12% or less, 10% or less, 8% or less, 6% or less. The resilience is usually greater than 0%, and can be 1% or more, 2% or more. (8.3) Hardness The hardness (JIS K6400-2:2012 6.7 Method D) is preferably 150N or higher, more preferably 180N or higher, and even more preferably 200N or higher, from the viewpoint of reducing bottoming out. The upper limit of the hardness is not particularly limited and may be, for example, 600N or less, 400N or less, 300N or less, or 270N or less. (8.4) Air permeability The air permeability (JIS K6400-7:2012 Method B) is preferably 0.01 cm 3 / cm 2 / sec or more, more preferably 0.05cm 3 / cm 2 It is 0.1 cm or more, and more preferably 0.1 cm. 3 / cm 2 It must be at least / sec. There is no particular upper limit on the ventilation rate, 100cm 3 / cm 2 / sec or less, 50cm 3 / cm 2 / sec or less, 10cm 3 / cm 2 It may be less than / sec.

[0041] Furthermore, if the air permeability is above the lower limit mentioned above, the defilm treatment of polyurethane foam can be suitably performed. Examples of defilm treatments include alkaline treatment and explosion treatment. Polyurethane foam from which part or all of the cell membrane has been removed by defilm treatment can have even greater air permeability compared to polyurethane foam before defilm treatment.

[0042] 2. Manufacturing of polyurethane foam Polyurethane foam can be produced by known foaming methods, which involve stirring and mixing a polyurethane resin composition to react a polyol with a polyisocyanate. Foaming methods include slab foaming and mold foaming, and either method may be used. Slab foaming involves extruding the mixed polyurethane resin composition onto a belt conveyor and foaming it on the conveyor to continuously form polyurethane foam. Mold foaming, on the other hand, involves filling a mold with the mixed polyurethane resin composition and foaming it within the mold.

[0043] 3. Applications of polyurethane foam The polyurethane foam of this embodiment is high-density, high-hardness, and low-rebound, making it useful for a variety of applications. For example, polyurethane foam is suitable as a cushioning material. When part or all of the cell membrane is removed from the polyurethane foam, sufficient breathability can be ensured, making it comfortable to use, for example, in applications that come into contact with the human body, as it is less likely to cause stuffiness. In other words, this disclosure is useful for devices, clothing, shoes, mats, or bedding equipped with the above-mentioned polyurethane foam. Examples of devices include headgear, helmets, knee pads, etc. [Examples]

[0044] 1. Manufacturing of polyurethane foam <Sample 1-Sample 12> To confirm the moldability of polyurethane foam, polyurethane resin compositions were prepared using the proportions shown in Table 1, and polyurethane foam was produced by hand foaming with a hand mixer. Details of each raw material are described later.

[0045] The condition of the polyurethane foam in Samples 1-12 was visually evaluated. A good condition was rated "Good," while defects such as shrinkage were rated "Poor." The results are shown in Table 1.

[0046] Of Samples 1-12, Samples 1-6 exhibited good foam quality. Using the formulations of Samples 1-6 as a reference, polyurethane foams for Examples 1-8 and the Comparative Example were prepared.

[0047] [Table 1]

[0048] <Examples 1-8, Comparative Examples> Polyurethane resin compositions were prepared using the proportions shown in Table 2, and polyurethane foams for Examples 1-8 and the Comparative Example were produced by mechanical foaming using a foam injection machine. Details of each ingredient are as follows: • Polyol 1: Polyether polyol, weight-average molecular weight 750, number of functional groups 3, hydroxyl value 220 mgKOH / g, product name GP-750K (manufactured by Sanyo Chemical Industries, Ltd.) • Polyol 2: Polyether polyol, weight-average molecular weight 3000, number of functional groups 3, hydroxyl value 56 mgKOH / g, product name SC56-18S (manufactured by SHELL EASTERN CHEMICALS) • Polyol 3: Polyester polyol, weight-average molecular weight 1000, number of functional groups 2, hydroxyl value 115 mgKOH / g, product name T-2467 (manufactured by Hitachi Chemical Polymers) • Catalyst 1: Amine catalyst, a mixture of triethylenediamine (TEDA) and dipropylene glycol (DPG), TEDA:DPG = 33:67, product name 33LSI (manufactured by Evonic Corporation) • Catalyst 2: Amine catalyst, N,N-dimethylaminohexanol, Product No. 25 (manufactured by Kao Corporation) • Catalyst 3: Metal catalyst, tin(II) octylate, product name MRH-110 (manufactured by Johoku Chemical Industry Co., Ltd.) • Foam stabilizer 1: Silicone-based foam stabilizer, product name L-595 (manufactured by Momentive). • Foam stabilizer 2: Silicone-based foam stabilizer, product name SZ-1136 (manufactured by Toray Dow Corporation) • Paraffin: Liquid paraffin, product name No. 350-S, (manufactured by Sanko Chemical Industry Co., Ltd.) • Dipropylene glycol (DPG) • Foaming agent: Water • Polyisocyanate: A mixture of 2,4-tolylene diisocyanate (2,4-TDI) and 2,6-tolylene diisocyanate (2,6-TDI), with a ratio of 2,4-TDI:2,6-TDI = 65:35, product name: Cosmonate T-65 (manufactured by Mitsui Chemicals, Inc.)

[0049] [Table 2]

[0050] 2. Evaluation Method (1) Density (apparent density) Density was measured according to JIS K7222:2005. (2) Rebound elasticity The rebound elasticity was measured according to JIS K6400-3:2011. (3) Hardness (25% ILD hardness) Hardness was measured according to JIS K6400-2:2012 6.7 Method D. (4) Airflow Air permeability was measured according to JIS K6400-7:2012 Method B.

[0051] 3.Results The results are shown in Tables 1 and 2. In Table 2, in the columns for 25% ILD hardness and air permeability, "-" indicates that evaluation was not performed.

[0052] Examples 1-8 satisfy the following requirements (a), (b), and (c). In contrast, Comparative Example 1 does not satisfy requirement (b). Requirement (a): A polyurethane foam obtained from a composition of a mixture of a polyol, a polyisocyanate, and paraffin. Requirement (b): Density (JIS K7222:2005) of 60 kg / m³ 3 That's all. Requirement (c): The rebound elasticity (JIS K6400-3:2011) is 15% or less.

[0053] Examples 1-8, which satisfy requirements (a), (b), and (c), yielded high-density, high-hardness, and low-rebound polyurethane foam. Furthermore, Examples 1-8, which satisfy requirements (a), (b), and (c), are high-density and low-rebound foams while also having an air permeability of 0.05 cm². 3 / cm 2 We were able to achieve a result of over / sec.

[0054] 4. Effects of the Examples This embodiment has provided a novel low-rebound polyurethane foam. For example, this embodiment has provided a high-density low-rebound polyurethane foam with ensured breathability.

[0055] This disclosure is not limited to the embodiments detailed above, and various modifications or changes are possible within the scope of this disclosure.

Claims

1. Polyols and, Polyisocyanate and, Paraffin and, A polyurethane foam obtained from a mixed composition, Density (JIS K 7222:2005) is 60 kg / m³ ３ That's all. Polyurethane foam with a rebound elasticity (JIS K 6400-3:2011) of 15% or less.

2. The polyurethane foam according to claim 1, wherein the hardness (JIS K 6400-2:2012 6.7 D method) is 150 N or more.

3. The polyurethane foam according to claim 1 or claim 2, wherein the polyol includes a polyester polyol.

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