Polyurethane foam and seat pad

Abstract

Provided is a technique capable of contributing to thinning of a product while using a plant-derived polyol.　The polyurethane foam is obtained from a composition containing a polyol and an isocyanate. The polyol contains a plant-derived polyol and has a compressive deflection coefficient of 2.8 or less as measured in accordance with a JIS K6400-2: 2012 E method.

Description

Polyurethane foam and seat pad

[0001] The present disclosure relates to polyurethane foams and seat pads.

[0002] Patent Document 1 discloses a urethane foam obtained using a petroleum-derived polyol and a modified plant-derived polyol.

[0003] International Publication No. 2007 / 020904

[0004] In recent years, from the perspective of reducing environmental impact, there has been a demand for technology that uses plant-derived materials instead of petroleum-derived materials made from petroleum resources. However, polyurethane foams using conventional plant-derived polyols merely maintain physical properties equivalent to those of polyurethane foams using 100% petroleum-derived polyols. There is a demand for technology that can accommodate thinner products while using plant-derived polyols. The present disclosure has been made in light of the above-mentioned circumstances, and aims to provide technology that can contribute to thinner products while using plant-derived polyols. The present disclosure can be realized in the following forms.

[0005] A polyurethane foam obtained from a composition containing a polyol and an isocyanate, wherein the polyol contains a plant-derived polyol, and the polyurethane foam has a compressive deflection coefficient of 2.8 or less as measured in accordance with JIS K6400-2:2012, Method E.

[0006] The polyurethane foam of the present disclosure can contribute to thinner products while using plant-derived polyols.

[0007] 1 is a top view of an example of a seat pad;

[0008] Hereinafter, preferred examples of the present disclosure will be described. [1] A polyurethane foam obtained from a composition containing a polyol and an isocyanate, wherein the polyol contains a plant-derived polyol, and the polyurethane foam has a compressive deflection coefficient of 2.8 or less as measured in accordance with JIS K6400-2:2012 Method E. [2] The polyurethane foam according to [1], wherein the plant-derived polyol is a polyol having a hydroxyl value of 40 mgKOH / g or more and 130 mgKOH / g or less. [3] The polyurethane foam according to [1] or [2], wherein the composition contains a silicone-based foam stabilizer having a viscosity of 900 mPa·s (25°C) or less and a surface tension of 24 mN / m or less. [4] The polyurethane foam according to any one of [1] to [3], wherein the proportion of plant-derived materials in the entire composition (plant content) is 10% or more. [5] The polyurethane foam according to any one of [1] to [4], wherein the composition contains a polyol having an ethylene oxide unit content of more than 50% by weight. [6] A seat pad comprising the polyurethane foam according to any one of [1] to [5].

[0009] The present disclosure will be described in detail below. In this specification, when a numerical range is indicated using "-", it is assumed that the range includes both the lower limit and the upper limit unless otherwise specified. For example, the expression "10-20" includes both the lower limit "10" and the upper limit "20". In other words, "10-20" has the same meaning as "10 or more and 20 or less". In addition, in this specification, the upper limit and lower limit of each numerical range can be combined in any way.

[0010] 1. Polyurethane foam The polyurethane foam is obtained from a composition containing a polyol and an isocyanate. The polyol contains a plant-derived polyol. The polyurethane foam has a compression deflection coefficient of 2.8 or less, measured in accordance with JIS K6400-2:2012, Method E.

[0011] The composition includes a polyol and an isocyanate. The composition may include at least one optional component selected from a blowing agent, a catalyst, a foam stabilizer, and a crosslinking agent. Each component of the composition will be described below.

[0012] (1) Polyol (1.1) Plant-derived polyol The plant-derived polyol is preferably at least one selected from the group consisting of castor oil-based polyol, soybean oil-based polyol, corn oil-based polyol, cashew oil-based polyol, palm oil-based polyol, palm kernel oil-based polyol, coconut oil-based polyol, olive oil-based polyol, cottonseed oil-based polyol, safflower oil-based polyol, sesame oil-based polyol, sunflower oil-based polyol, and linseed oil-based polyol. Only one plant-derived polyol may be used, or two or more plant-derived polyols may be used. The plant-derived polyol is particularly preferably a castor oil-based polyol.

[0013] The castor oil-based polyol may be a modified castor oil polyol derived from modified castor oil, or may be an unmodified castor oil polyol derived from unmodified castor oil. Unmodified castor oil is, for example, extracted from the seeds of castor bean (castor oil) of the Euphorbiaceae family and purified. Unmodified castor oil is an ester of fatty acids and glycerin. Unmodified castor oil is mainly composed of ricinoleic acid.

[0014] In the present disclosure, ricinoleic acid and fatty acids derived from ricinoleic acid are also referred to as castor oil fatty acids. A specific example of a fatty acid derived from ricinoleic acid is sebacic acid.

[0015] From the viewpoint of reducing the compression deflection coefficient, the castor oil-based polyol is preferably a modified castor oil polyol. The modified castor oil polyol is, for example, a linear or branched polyester polyol obtained by reacting a castor oil fatty acid with a polyol (a). The modified castor oil polyol also includes sebacic acid polyester polyol.

[0016] Specific examples of modified castor oil polyols include diglycerides of castor oil fatty acids, monoglycerides of castor oil fatty acids, monoesters of castor oil fatty acids and trimethylolalkanes, diesters of castor oil fatty acids and trimethylolalkanes, triesters of castor oil fatty acids and trimethylolalkanes, monoesters of castor oil fatty acids and polypropylene glycol, diesters of castor oil fatty acids and polypropylene glycol, triesters of castor oil fatty acids and polypropylene glycol, and the like.

[0017] The polyol (a) is preferably at least one selected from the group consisting of low-molecular-weight polyols (a1) and polyether polyols (a2).

[0018] The low molecular weight polyol (a1) is, for example, one or more selected from the group consisting of ethylene glycol, diethylene glycol, propylene glycol, 1,2-, 1,3-, or 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexane glycol, 1,8-octanediol, 1,10-decanediol, neopentyl glycol, hydrogenated bisphenol A, glycerin, trimethylolalkane, hexanetriol, pentaerythritol, sorbitol, and sucrose. Specific examples of trimethylolalkane include trimethylolmethane, trimethylolethane, trimethylolpropane, trimethylolbutane, trimethylolpentane, trimethylolhexane, trimethylolheptane, trimethyloloctane, trimethylolnonane, and trimethyloldecane. The molecular weight of the low-molecular-weight polyol (a1) is usually 50-200.

[0019] The polyether polyol (a2) is, for example, a polymer obtained by adding an alkylene oxide having 2 to 8 carbon atoms to a low-molecular-weight polyol (a1) as an initiator. Specific examples of the alkylene oxide having 2 to 8 carbon atoms include ethylene oxide, propylene oxide, and butylene oxide. Specific examples of the polyether polyol (a2) include polypropylene glycol, polyethylene glycol, polytetramethylene glycol, and chipped ether, which is a copolymer of ethylene oxide and propylene oxide.

[0020] The number of functional groups, hydroxyl value, and number-average molecular weight of the plant-derived polyol are not particularly limited. The number of functional groups of the plant-derived polyol is preferably 2.0 to 6.0, more preferably 2.5 to 5.5, and even more preferably 3.0 to 5.0. The hydroxyl value of the plant-derived polyol is preferably 40 mgKOH / g to 130 mgKOH / g, more preferably 40 mgKOH / g to 100 mgKOH / g, even more preferably 45 mgKOH / g to 70 mgKOH / g, and particularly preferably 50 mgKOH / g to 60 mgKOH / g. The number-average molecular weight of the plant-derived polyol is preferably 800 to 10,000, more preferably 1,000 to 7,000, and even more preferably 2,000 to 6,000. In the present disclosure, the number-average molecular weight of the polyol can be measured, for example, by gel permeation chromatography (GPC). When the polyol contains two or more plant-derived polyols, it is preferable that at least one of the plant-derived polyols falls within the above range.

[0021] The content of the plant-derived polyol is preferably 10 parts by mass or more, more preferably 15 parts by mass or more, even more preferably 20 parts by mass or more, even more preferably 25 parts by mass or more, and particularly preferably 30 parts by mass or more, from the viewpoint of increasing the plant content, where the total amount of polyol is 100 parts by mass. From the viewpoint of ensuring various physical properties, the content of the plant-derived polyol is preferably 60 parts by mass or less, more preferably 50 parts by mass or less, even more preferably 45 parts by mass or less, even more preferably 40 parts by mass or less, and particularly preferably 36 parts by mass or less. From these viewpoints, the content of the plant-derived polyol is preferably 10 parts by mass or more and 60 parts by mass or less, more preferably 15 parts by mass or more and 55 parts by mass or less, even more preferably 20 parts by mass or more and 50 parts by mass or less, even more preferably 25 parts by mass or more and 45 parts by mass or less, and particularly preferably 30 parts by mass or more and 36 parts by mass or less.

[0022] (1.2) Petroleum-derived polyol The polyol preferably contains a petroleum-derived polyol. The petroleum-derived polyol is not particularly limited. Examples of petroleum-derived polyols include polyether polyols, polymer polyols, and polyester polyols.

[0023] The polyether polyol is preferably at least one selected from the group consisting of polyether polyols obtained by adding an alkylene oxide such as ethylene oxide (EO) or propylene oxide (PO) to a polyhydric alcohol such as ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, or sucrose. The polyether polyol may be one type only, or two or more types may be used.

[0024] Hereinafter, the content of ethylene oxide units (EO units) in a polyether polyol when the total amount of alkylene oxide units is taken as 100% by weight will also be referred to as the "EO unit content."

[0025] The polyether polyol preferably contains two types of polyether polyols with different EO unit contents. By containing two types of polyether polyols with different properties, the polyether polyol can improve gas release properties during molding. Hereinafter, of the two types of polyether polyols, the polyether polyol with the higher content in the composition will be referred to as the "first polyether polyol," and the polyether polyol with the lower content will be referred to as the "second polyether polyol." The second polyether polyol acts as a so-called degassing agent.

[0026] The polyether polyol contains, for example, a first polyether polyol having an EO unit content of 50 wt% or less and a second polyether polyol having an EO unit content of more than 50 wt%. The EO unit content of the first polyether polyol is preferably 0 wt% to 40 wt%, more preferably 0 wt% to 30 wt%, and even more preferably 0 wt% to 20 wt%. The EO unit content of the second polyether polyol is preferably 55 wt% to 100 wt%, more preferably 60 wt% to 100 wt%.

[0027] The number of functional groups, hydroxyl value, and number average molecular weight of the first polyether polyol are not particularly limited. The number of functional groups of the first polyether polyol is preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less. The number of functional groups of the first polyether polyol is usually 2.0 or more. The hydroxyl value of the first polyether polyol is preferably 10 mg KOH / g or more and 120 mg KOH / g or less, more preferably 15 mg KOH / g or more and 100 mg KOH / g or less, and even more preferably 20 mg KOH / g or more and 60 mg KOH / g or less. The number average molecular weight of the first polyether polyol is preferably 1,000 or more and 12,000 or less, more preferably 2,500 or more and 10,000 or less, even more preferably 4,000 or more and 9,000 or less, and particularly preferably 5,000 or more and 8,000 or less. The total degree of unsaturation of the first polyether polyol, as shown in the method described in JIS K1557-3:2007 as an index of the amount of monool by-product, is preferably 0.07 meq / g or less, more preferably 0.06 meq / g or less, and even more preferably 0.05 meq / g or less. The total degree of unsaturation of the polyether polyol is usually 0.001 meq / g or more.

[0028] The content of the first polyether polyol is preferably 20 parts by mass or more, more preferably 25 parts by mass or more, even more preferably 30 parts by mass or more, and particularly preferably 35 parts by mass or more, from the viewpoint of ensuring various physical properties, when the total amount of polyols is 100 parts by mass. From the viewpoint of increasing the plant-derived content by sufficiently blending the plant-derived polyol, the content of the first polyether polyol is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 60 parts by mass or less. From these viewpoints, the content of the first polyether polyol is preferably 20 parts by mass or more and 70 parts by mass or less, more preferably 25 parts by mass or more and 65 parts by mass or less, even more preferably 30 parts by mass or more and 60 parts by mass or less, and particularly preferably 35 parts by mass or more and 60 parts by mass or less.

[0029] The number of functional groups, hydroxyl value, and number average molecular weight of the second polyether polyol are not particularly limited. The number of functional groups of the second polyether polyol is preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less. The number of functional groups of the second polyether polyol is usually 2.0 or more. The hydroxyl value of the second polyether polyol is preferably 10 mg KOH / g or more and 140 mg KOH / g or less, more preferably 20 mg KOH / g or more and 120 mg KOH / g or less, and even more preferably 30 mg KOH / g or more and 80 mg KOH / g or less. The number average molecular weight of the second polyether polyol is preferably 1,000 or more and 10,000 or less, more preferably 2,000 or more and 8,000 or less, even more preferably 3,000 or more and 7,000 or less, and particularly preferably 4,000 or more and 6,000 or less.

[0030] The content of the second polyether polyol is preferably 0 parts by mass or more and 5 parts by mass or less, more preferably 0 parts by mass or more and 4 parts by mass or less, and even more preferably 0 parts by mass or more and 3 parts by mass or less, from the viewpoint of ensuring various physical properties, when the total amount of polyols is 100 parts by mass.

[0031] The polymer polyol may be, for example, a liquid containing a fine particle polymer dispersed in a polyol. Examples of the fine particle polymer include polymers such as acrylonitrile, styrene, acrylic, and melamine, and polyurea. The polymer polyol is preferably a polyether polyol (base polyol) polymerized with or mixed with acrylonitrile and / or styrene. The polymer polyol may be one type or two or more types.

[0032] The number of functional groups, hydroxyl value, and number average molecular weight of the polymer polyol are not particularly limited. The number of functional groups of the polymer polyol is preferably 4.0 or less, more preferably 3.5 or less, and even more preferably 3.0 or less. The number of functional groups of the polyether polyol is usually 2.0 or more. The hydroxyl value of the polymer polyol is preferably 10 mgKOH / g or more and 60 mgKOH / g or less, more preferably 13 mgKOH / g or more and 50 mgKOH / g or less, and even more preferably 16 mgKOH / g or more and 40 mgKOH / g or less. The number average molecular weight of the polymer polyol is preferably 1,000 or more and 12,000 or less, more preferably 2,000 or more and 10,000 or less, even more preferably 3,000 or more and 9,000 or less, and particularly preferably 4,000 or more and 8,000 or less. When the polyol contains two or more polymer polyols, it is preferable that at least one of the polymer polyols is within the above range.

[0033] The content of the petroleum-derived polyol is not particularly limited. For example, the content of the petroleum-derived polyol is the sum of the content of the first polyether polyol, the content of the second polyether polyol, and the content of the polymer polyol. From the viewpoint of ensuring various physical properties, the content of the petroleum-derived polyol is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, and even more preferably 55 parts by mass or more, when the total amount of polyols is 100 parts by mass. From the viewpoint of improving the plant content by sufficiently blending the plant-derived polyol, the content of the petroleum-derived polyol is preferably 90 parts by mass or less, more preferably 80 parts by mass or less, and even more preferably 75 parts by mass or less. From these viewpoints, the content of the petroleum-derived polyol is preferably 40 parts by mass or more and 90 parts by mass or less, more preferably 50 parts by mass or more and 80 parts by mass or less, and even more preferably 55 parts by mass or more and 75 parts by mass or less.

[0034] (2) Blowing Agent The blowing agent may be water, a chlorofluorocarbon alternative, or a hydrocarbon such as pentane, which may be used alone or in combination. The most preferred blowing agent is water.

[0035] The amount of water as a blowing agent is preferably 0.5 parts by mass or more and 4.0 parts by mass or less, more preferably 1.0 parts by mass or more and 3.0 parts by mass or less, and even more preferably 1.5 parts by mass or more and 2.5 parts by mass or less, relative to 100 parts by mass of the total amount of polyol.

[0036] (3) Catalyst The catalyst is primarily used to promote the urethane reaction between the polyol and the isocyanate. Examples of the catalyst include tertiary amines such as triethylenediamine, bis(2-dimethylaminoethyl)ether, 6-dimethylamino-1-hexanol, N,N-dimethylaminoethanol, and N,N',N'-trimethylaminoethylpiperazine, organometallic compounds such as stannous octoate and stannous octoate, acetates, and alkali metal alcoholates.

[0037] The total content of the catalyst is preferably 0.3 parts by mass or more and 5.0 parts by mass or less, more preferably 0.5 parts by mass or more and 4.0 parts by mass or less, and even more preferably 0.8 parts by mass or more and 3.0 parts by mass or less, when the total amount of the polyol is 100 parts by mass.

[0038] (4) Foam Stabilizer Examples of foam stabilizers that can be used include silicone compounds such as organopolysiloxane, organopolysiloxane-polyoxyalkylene copolymer, polyalkenylsiloxane having a polyoxyalkylene side chain, silicone-grease copolymer, etc., anionic surfactants such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate, polyether siloxane, phenolic compounds, etc. Only one type of foam stabilizer may be used, or two or more types may be used.

[0039] After extensive research, the present inventors have newly discovered that the compressive deflection coefficient can be reduced by combining a plant-derived polyol with a specific type of foam stabilizer. A preferred example of a foam stabilizer to be combined with a plant-derived polyol is the silicone-based foam stabilizer "B8738LF2" manufactured by EVONIK. It was found that the compressive deflection coefficient decreases as the amount of silicone-based foam stabilizer "B8738LF2" added to the composition increases. Note that when the silicone-based foam stabilizer "B8738LF2" is used in a composition that does not contain a plant-derived polyol, the effect of reducing the compressive deflection coefficient is not confirmed even when the amount of silicone-based foam stabilizer "B8738LF2" added increases. These results suggest that the combination of a plant-derived polyol and a silicone-based foam stabilizer "B8738LF2" is effective in reducing the compressive deflection coefficient.

[0040] The viscosity and surface tension of a foam stabilizer are among the factors thought to contribute to a polyurethane foam foaming system. The viscosity of a foam stabilizer can be measured, for example, in accordance with JIS K1557-5 using an E-type viscometer at 25°C. The surface tension of a foam stabilizer can be measured by the Wilhelmy method using a dynamic wettability tester MODE WET-6100 manufactured by RHESCA under conditions of an immersion speed of 3 mm / s, an immersion depth of 3 mm, and an immersion time of 300 seconds. The viscosity and surface tension of the silicone-based foam stabilizer "B8738LF2" manufactured by EVONIC are as follows. Silicone-based foam stabilizer "B8738LF2": Viscosity 40 mPa·s (25°C), surface tension 20.57 mN / m (25°C)

[0041] The viscosity of the foam stabilizer according to JIS K1557-5 is preferably 900 mPa·s (25°C) or less, more preferably 500 mPa·s (25°C) or less, and even more preferably 100 mPa·s (25°C) or less. The lower limit of the viscosity of the foam stabilizer is not particularly limited, and is usually greater than 1 mPa·s (25°C). The surface tension (25°C) of the foam stabilizer according to the Wilhelmy method is preferably 24 mN / m or less, more preferably 23 mN / m or less, and even more preferably 18 mN / m or more and 22 mN / m or less.

[0042] The content of the foam stabilizer is not particularly limited. From the viewpoint of reducing the compression deflection coefficient, the content of the foam stabilizer is preferably 0.35 parts by mass or more, more preferably 0.4 parts by mass or more, and even more preferably 0.5 parts by mass or more, based on 100 parts by mass of the total amount of polyol. The upper limit of the content of the foam stabilizer is not particularly limited, and is, for example, 3 parts by mass or less.

[0043] (5) Crosslinking Agent A crosslinking agent is blended to improve the hardness and tear strength of the polyurethane foam, and is particularly effective for increasing hardness. The crosslinking agent is, for example, one or more selected from the group consisting of polyhydric alcohols, ethanolamines, and polyethylene polyamines. Specific examples of polyhydric alcohols include glycerin, trimethylolpropane, 1,4-butanediol, and diethylene glycol. Specific examples of ethanolamines include diethanolamine. The total content of the crosslinking agent is preferably 0.1 parts by mass or more and 6 parts by mass or less, and more preferably 0.3 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the total amount of polyol.

[0044] (6) Other Additives The composition may contain other additives as appropriate, such as plasticizers, fillers, antioxidants, ultraviolet absorbers, defoamers, compatibilizers, colorants, stabilizers, antibacterial agents, antifungal agents, deodorizers, deodorizers, fragrances, and flavorings.

[0045] (7) Isocyanate The isocyanate is not particularly limited as long as it is a compound having two or more isocyanate groups, and isocyanates for polyurethane foams can be used. The isocyanates may be used alone or in combination of two or more. The isocyanate is preferably selected from the group consisting of aromatic, aliphatic, and alicyclic isocyanate compounds, and modified products thereof.

[0046] Examples of aromatic isocyanate compounds include toluylene diisocyanate (tolylene diisocyanate, TDI), diphenylmethane diisocyanate (MDI), crude diphenylmethane diisocyanate (polymethylene polyphenylene polyisocyanate, polymeric MDI), naphthalene diisocyanate (NDI), p-phenylene diisocyanate (PPDI), xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), tolidine diisocyanate (TODI), etc. Aliphatic isocyanate compounds are preferably selected from the group consisting of hexamethylene diisocyanate (HDI), lysine diisocyanate (LDI), and lysine triisocyanate (LTI). The alicyclic isocyanate compound is preferably selected from the group consisting of isophorone diisostearyl diisocyanate (IPDI), cyclohexyl diisocyanate (CHDI), hydrogenated XDI (H6XDI), and hydrogenated MDI (H12MDI). The modified isocyanate compound is preferably selected from the group consisting of urethane-modified, dimer-, trimer-, carbodiimide-modified, allophanate-modified, biuret-modified, urea-modified, isocyanurate-modified, oxazolidone-modified, and isocyanate-terminated prepolymers of isocyanate compounds.

[0047] The isocyanate preferably used is an aromatic isocyanate compound, and more preferably toluylene diisocyanate (TDI) and / or diphenylmethane diisocyanate (MDI). The diphenylmethane diisocyanate is preferably polymethylene polyphenylene polyisocyanate. When TDI and MDI are used in combination, the mixing ratio of the TDI to MDI mixture (TDI:MDI, mass ratio) is preferably 50 / 50-90 / 10, more preferably 75 / 25-85 / 15. The toluylene diisocyanate (TDI) preferably used is 2,4-toluylene diisocyanate (2,4-TDI) and / or 2,6-toluylene diisocyanate (2,6-TDI). When 2,4-TDI and 2,6-TDI are used in combination, the mixing ratio of the mixture of 2,4-TDI and 2,6-TDI (2,4-TDI / 2,6-TDI, mass ratio) is preferably 50 / 50 to 90 / 10, more preferably 75 / 25 to 85 / 15.

[0048] The isocyanate index of the composition can be appropriately set. The isocyanate index is calculated by dividing the number of moles of isocyanate groups in the isocyanate by the total number of moles of active hydrogen groups, such as hydroxyl groups, in the polyol, and multiplying the result by 100. The isocyanate index is calculated by [NCO equivalent of isocyanate / active hydrogen equivalent × 100].

[0049] 2. Method for Producing Polyurethane Foam Polyurethane foam can be produced by a known foaming method in which the above composition is stirred and mixed to react the polyol and polyisocyanate. Foaming methods include slab foaming and mold foaming, with mold foaming being preferred. Slab foaming is a method in which the mixed composition is discharged onto a belt conveyor and foamed at atmospheric pressure and room temperature. On the other hand, mold foaming is a method in which the mixed composition is filled into a mold (forming die) and foamed within the mold.

[0050] 3. Plant-based Content of Polyurethane Foam The plant-based content of a polyurethane foam is the proportion of plant-derived materials in the entire composition. From the viewpoint of reducing environmental impact, the plant-based content of a polyurethane foam is preferably 10% or more, more preferably 15% or more, and even more preferably 20% or more. The upper limit of the plant-based content of a polyurethane foam is not particularly limited and may be, for example, 40% or less, 30% or less, or 25% or less. The plant-based content of a polyurethane foam can be calculated using the following formula (1):

[0051] Plant-derived content of polyurethane foam = ((A x B) / C) x 100 (1) A: Amount of plant-derived polyol (parts by mass) B: Plant-derived content of plant-derived polyol (%) / 100 C: Total amount of composition (parts by mass) "Plant-derived content of plant-derived polyol / 100" refers to the mass proportion of plant-derived materials among the raw materials of the plant-derived polyol. "Total amount of composition" refers to the total number of parts by mass of all raw materials of the composition. All raw materials include plant-derived polyol, petroleum-derived polyol, blowing agent, catalyst, foam stabilizer, crosslinking agent, isocyanate, etc.

[0052] 4. Physical Properties of Polyurethane Foam The physical properties of the polyurethane foam can be appropriately set depending on the application, etc. It is preferable that the polyurethane foam has the following physical properties.

[0053] (1) Density (Apparent Density) The density of polyurethane foam (in accordance with JIS K7222:2005) is 0.040 g / cm ３ 0.100g / cm or more ３ Preferably, 0.045 g / cm or less ３ 0.080g / cm or more ３ More preferably, 0.050 g / cm or less ３ 0.070g / cm or more ３ The following is even more preferred:

[0054] (2) 25% Hardness The 25% hardness of the polyurethane foam (based on JIS K6400-2:2012 D method) is not particularly limited. The 25% hardness of the polyurethane foam is preferably 80 N or more and 400 N or less, more preferably 120 N or more and 350 N or less, and even more preferably 160 N or more and 300 N or less. The test specimen used for measurement is the entire polyurethane foam including the skin. For example, in the examples described below, the test specimen is a rectangular parallelepiped having a length of 400 mm, a width of 400 mm, and a height of 100 mm, including the skin. A pressure plate with a diameter of 200 mm is used for measurement. During measurement, the test specimen is placed on the support plate of the testing machine so that the center of the test specimen is at the center of the pressure plate.

[0055] (3) Hysteresis Loss Rate From the viewpoint of durability, the hysteresis loss rate of the polyurethane foam (based on JIS K6400-2:2012 Method E) is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less. The lower limit of the hysteresis loss rate is not particularly limited and is usually 5.0% or more. When obtaining a force-deflection curve based on JIS K6400-2:2012 Method E, the load required to return from pressure to pressure during compression of the seat pad is 980 N. The test specimen used for measurement is the entire polyurethane foam, including the skin. For example, in the examples described below, a rectangular parallelepiped measuring 400 mm in length, 400 mm in width, and 100 mm in height, including the skin, is used as the test specimen. A pressure plate with a diameter of 200 mm is used for measurement. During measurement, the test specimen is placed on the support plate of the testing machine so that the center of the test specimen is at the center of the pressure plate.

[0056] (4) Compression Deflection Coefficient The compression deflection coefficient of the polyurethane foam (based on JIS K6400-2:2012 Method E) is 2.8 or less, and may be 2.7 or less, 2.6 or less, 2.5 or less, or 2.4 or less, from the viewpoint of reducing the feeling of bottoming out. The lower limit of the compression deflection coefficient of the polyurethane foam is not particularly limited, and may be, for example, 2.0 or more, 2.2 or more. The test piece used for measurement and the method for obtaining the force-deflection curve are the same as those for the test piece and the method for obtaining the force-deflection curve in (3) Measurement of Hysteresis Loss Rate. The compression deflection coefficient is calculated by the following formula: Compression deflection coefficient = (Load (N) at 65% compression) / (Load (N) at 25% compression)

[0057] When polyurethane foam is used as, for example, the seat pad 110 in FIGS. 1 and 2 , the compression deflection coefficient can be measured as follows. A pressure plate 120 is placed on the portion of the seat pad that contacts the buttocks, and a force-deflection curve is plotted in accordance with JIS K6400-2:2012, Method E. When plotting the force-deflection curve, the load required to return from pressurization to depressurization during compression of the seat pad is set to 980 N. The forces at 65% compression and 25% compression are determined as follows. The initial thickness (thickness before compression) of the thinnest point P1, located below the pressure plate 120, is taken as 100%, and the force at 25% compression is the force at which the thickness Tmin at the thinnest point P1 is compressed by 25% of its initial thickness to 75%. The force at 65% compression is the force at which the thickness Tmin at the thinnest point P1 is compressed by 65% ​​of its initial thickness to 35%. The compression deflection coefficient is then calculated based on the above formula. The shape of the seat pad is not limited to the shapes shown in FIGS. 1 and 2 . For example, the shape of the seat pad may be a rectangular parallelepiped, as in the examples described later. In the examples described later, a rectangular parallelepiped having a length of 400 mm, a width of 400 mm, and a height of 100 mm, including the skin, is used as the test piece. Therefore, the initial thickness (thickness before compression) of the thickness Tmin at the thinnest position P1 is 100 mm, the thickness at 25% compression is 75 mm, and the thickness at 65% compression is 35 mm.

[0058] (5) Stress Relaxation Rate From the viewpoint of durability, the stress relaxation rate of the polyurethane foam is preferably 24% or less, more preferably 20% or less, and even more preferably 15% or less. The lower limit of the stress relaxation rate is not particularly limited and may be, for example, 1% or more. The smaller the stress relaxation rate, the less sagging of the urethane foam after sitting and the better the durability. The stress relaxation rate tends to increase as the thickness of the polyurethane foam decreases. The technology disclosed herein is particularly useful in that it can reduce the stress relaxation rate even in thin-walled products (such as the seat pad 10 described below). The stress relaxation rate (%) can be measured as follows. The test specimen used for measurement is the entire polyurethane foam, including the skin. For example, in the examples described below, a rectangular parallelepiped with dimensions of 400 mm length, 400 mm width, and 100 mm height, including the skin, is used as the test specimen. A circular pressure plate with a diameter of 200 mm is used to compress the polyurethane foam to a distance of 75% of its initial thickness at a rate of 50 mm / min. The load is then removed and the foam is left to stand for 1 minute. The load is again applied at the same speed, and when the load reaches 196 N (20 kgf), the pressure plate is stopped and the load is read after leaving it for 5 minutes.The stress relaxation rate is then calculated using the following formula: Stress relaxation rate (%) = 100 x [load when pressure plate is stopped (196 N) - load after leaving it for 5 minutes] / load when pressure plate is stopped (196 N).

[0059] (6) Rebound Resilience The rebound resilience of the polyurethane foam (based on JIS K6400-3:2011) is preferably 80% or less, more preferably 75% or less, and even more preferably 70% or less, from the viewpoint of improving ride comfort, etc. The lower limit of the rebound resilience of the polyurethane foam is not particularly limited, and may be, for example, 20% or more, 30% or more, or 40% or more.

[0060] (7) Tensile Strength, Elongation, and Tear Strength The tensile strength (according to JIS K6400-5:2012 3) is preferably 40 kPa or more, more preferably 60 kPa or more, and even more preferably 80 kPa or more. The upper limit of the tensile strength is not particularly limited, and is, for example, 200 kPa or less. The elongation (according to JIS K6400-5:2012 3) is preferably 50% or more and 500% or less, more preferably 80% or more and 200% or less, and even more preferably 90% or more and 150% or less. The tear strength (according to JIS K6400-5:2012, Type 4) is preferably 1 N / cm or more, more preferably 2 N / cm or more, and even more preferably 3 N / cm or more. The upper limit of the tear strength is not particularly limited, and is, for example, 10 N / cm or less.

[0061] (8) Compression Set (Dry Heat Set), Wet Heat Compression Set, Repeated Compression Set, 25% Hardness Change Rate After Repeated Compression The compression set (JIS K6400-4:2004 4.5 A method compliant, dry heat set) is preferably 20% or less, and may be 15% or less, 10% or less, 5% or less, or 3% or less. The wet heat compression set (JIS K6400-4:2004 compliant) is preferably 20% or less, and may be 15% or less, or 12% or less. The repeated compression set (JIS K6400-4:2004 6.1 A method compliant) is preferably 20% or less, and may be 15% or less, 10% or less, 5% or less, or 3% or less. The 25% hardness change rate after repeated compression is preferably 10% or less, and may be 6% or less, or 4% or less. The 25% hardness change rate under repeated compression can be calculated by the following formula after conducting a repeated compression residual strain test in accordance with JIS K6400-4:2004 6.1 A method, measuring the 25% hardness, and using the following formula: 25% hardness change rate under repeated compression = ((H1 - H2) / H1) x 100, where H1 is the initial 25% hardness (N) and H2 is the 25% hardness after the test (N).

[0062] (9) Airflow rate: Airflow rate (JIS K6400-7:2012 B method) is 10 cm ３ / cm ２ / s or more, and ３ / cm ２The upper limit of the air permeability is not particularly limited, and is, for example, 100 cm ３ / cm ２ The air permeability (according to ASTM D3574) is preferably 30 L / min or more. The upper limit of the air permeability is not particularly limited, and may be, for example, 100 L / min or less.

[0063] 5. Uses of Polyurethane Foam The polyurethane foam of the present disclosure has a sufficiently low compression deflection coefficient, making it suitable for seat pads, particularly vehicle seat pads. It is generally believed that a polyurethane foam with a low compression deflection coefficient is highly flexible. Deflection characteristics in the low load range can be an indicator of the feeling of bottoming out when a person sits on it. Deflection characteristics in the high load range (e.g., 700 N or more but 980 N or less) can be an indicator of the feeling of bottoming out when vibrations occur during driving, etc. The present inventors have developed a technology that reduces the feeling of bottoming out, primarily in the high load range, by achieving a compression deflection coefficient of 2.8 or less in a seat pad using a plant-derived polyol, thereby contributing to the reduction of seat pad thickness. The technology of the present disclosure is groundbreaking in that it achieves a compression deflection coefficient of 2.8 or less while using a plant-derived polyol.

[0064] The polyurethane foam of the present disclosure can achieve a reduced compression deflection coefficient while using a plant-derived polyol. As a result, the polyurethane foam of the present disclosure contributes to reducing environmental impact and has excellent deflection properties, making it suitable for use in bedding such as mattresses, pillows, and futons.

[0065] The present disclosure will be specifically described below using examples. 1. Sample Preparation Compositions were prepared using the blending ratios shown in Tables 1 to 5, and samples of each example and comparative example were prepared by mold foaming. Each sample was a regular square prism measuring 400 mm in length, 400 mm in width, and 100 mm in thickness.

[0066] Details of the main ingredients are as follows: Petroleum-derived polyol 1, polyether polyol, EO unit content 14% by weight, functionality 3, hydroxyl value 33 mg KOH / g, number average molecular weight 5000 Petroleum-derived polyol 2: petroleum-derived polyol, polyether polyol, EO unit content 50% by weight or less, functionality 3, hydroxyl value 24 mg KOH / g, number average molecular weight 7000 Petroleum-derived polyol 3, polymer polyol, polymer content 32% by mass, hydroxyl value 25 mg KOH / g Plant-derived polyol 1, modified castor oil polyol (87% plant-based content), hydroxyl value 53 mg KOH / g, EBT-500, manufactured by Mitsui Chemicals, Inc. Plant-derived polyol 2, unmodified castor oil polyol (100% plant-based content), functionality 2.7, hydroxyl value 160 mg KOH / g, H-30, manufactured by Ito Oil Mills, Inc. Plant-derived polyol 3, modified soy polyol (80% plant-derived), hydroxyl value 75 mg KOH / g, FS-3500E, manufactured by Kaka Chemical Co., Ltd. Crosslinking agent 1: glycerin Crosslinking agent 2: diethanolamine 80%, water 20% Catalyst 1: bis(2-dimethylaminoethyl) ether Catalyst 2: triethylenediamine 33%, 1,2-propanediol 67%

[0067] Foam stabilizer 1: Silicone-based foam stabilizer, product number: L-3184J, manufactured by MOMENTIVE Foam stabilizer 2: Silicone-based foam stabilizer, product number: B8738LF2, manufactured by EVONIK Foam stabilizer 3: Silicone-based foam stabilizer, product number: B8715LF2, manufactured by EVONIK The viscosity, surface tension, hydroxyl value, and density of each foam stabilizer are as shown in Table 6. The viscosity and surface tension were measured by the method described in the embodiment.

[0068] Petroleum-derived polyol 4 (degassing agent): polyether polyol, EO unit content greater than 50% by weight, functionality 3, hydroxyl value 37 mg KOH / g, number average molecular weight 5000 Blowing agent: water Isocyanate: 80% mixture of 2,4-toluylene diisocyanate and 2,6-toluylene diisocyanate in a mass ratio of 80:20, polymethylene polyphenylene polyisocyanate 20%, NCO% 44.8% The blending ratio of isocyanate (liquid B) to liquid A was adjusted to obtain the isocyanate index shown in Tables 1 to 5.

[0069]

[0070]

[0071]

[0072]

[0073]

[0074]

[0075] 2. Evaluation Methods (1) Botanical Content of Polyurethane Foam The botanical content (%) of the polyurethane foam was calculated by the method described in the embodiment. (2) Density (Apparent Density) The density (g / cm ３) was measured in accordance with JIS K7222:2005. (3) 25% Hardness The 25% hardness (N / φ200) of polyurethane foam was measured in accordance with JIS K6400-2:2012, Method D. (4) Hysteresis Loss Rate The hysteresis loss rate (%) of polyurethane foam was measured in accordance with JIS K6400-2:2012, Method E. (5) Compression Deflection Coefficient The compression deflection coefficient of polyurethane foam was measured in accordance with JIS K6400-2:2012, Method E. (6) Stress Relaxation Rate The stress relaxation rate (%) of polyurethane foam was measured by the method described in the embodiment. (7) Rebound Resilience The rebound resilience (%) of polyurethane foam was measured in accordance with JIS K6400-3:2011. (8) Tensile Strength, Elongation, and Tear Strength Tensile strength (kPa) was measured in accordance with JIS K6400-5:2012, Section 3. Elongation (%) was measured in accordance with JIS K6400-5:2012, Section 3. Tear strength (N / cm) was measured in accordance with JIS K6400-5:2012. Test specimens were type 4. (9) Compression Set (Dry Heat Set), Wet Heat Compression Set, Repeated Compression Set, and 25% Hardness Change Rate After Repeated Compression The compression set (%) was measured in accordance with JIS K6400-4:2004, Section 4.5, A method. Note that, during measurement, the test specimens were compressed to 75% of their initial thickness. Wet heat compression set (%) was measured in accordance with JIS K6400-4:2004. The repeated compression residual strain (%) was measured in accordance with JIS K6400-4:2004 6.1 A method. The 25% hardness change rate (%) after repeated compression was calculated using the method described in the embodiment. (10) Air Permeability Air permeability (cm ３ / cm ２ / s) was measured in accordance with JIS K6400-7:2012 Method B. Air permeability (L / min) was measured in accordance with ASTM D3574.

[0076] 3. Results Examples 1 to 6 satisfy the following requirements (a) to (c). Requirement (a): The polyurethane foam is obtained from a composition containing a polyol and an isocyanate. Requirement (b): The polyol contains a plant-derived polyol. Requirement (c): The compressive deflection coefficient measured in accordance with JIS K6400-2:2012 Method E is 2.8 or less. Comparative Examples 1, 8, and 9 do not satisfy requirements (b) and (c). Comparative Examples 2 to 7 and 10 to 13 do not satisfy requirement (c).

[0077] Examples 1 to 6 that satisfy requirements (a) to (c) have a small compressive deflection coefficient, which contributes to thinner products. Examples 1 to 6 that satisfy requirements (a) to (c) use plant-derived polyols, which contribute to reducing the environmental impact.

[0078] Examples 1 to 3, Comparative Example 4, and Comparative Example 5, which differ in the amount of foam stabilizer 2 (silicone-based foam stabilizer "B8738LF2") added, are compared. It was found that as the amount of foam stabilizer 2 added increased from 0.20 parts by mass to 1.00 parts by mass, the compressive deflection coefficient decreased from 3.07 to 2.39. Note that Comparative Examples 1 and 8 are examples in which the amounts of foam stabilizer 2 added were 0.10 parts by mass and 1.00 parts by mass, respectively, in compositions that did not contain a plant-derived polyol. The compressive deflection coefficient of Comparative Example 1 was 3.10. The compressive deflection coefficient of Comparative Example 8 was 3.10. When a composition that did not contain a plant-derived polyol was used, no effect of reducing the compressive deflection coefficient was confirmed even when the amount of foam stabilizer 2 added increased. These results suggest that the combined use of foam stabilizer 2 and a plant-derived polyol can contribute to a reduction in the compressive deflection coefficient.

[0079] Examples 4 to 6, which differ in the amount of petroleum-derived polyol 4 (degassing agent) added, were compared. It was found that as the amount of petroleum-derived polyol 4 added increased from 0.50 parts by mass to 2.00 parts by mass, the compression deflection coefficient decreased from 2.50 to 2.30. This result suggests that the combined use of foam stabilizer 2 and petroleum-derived polyol 4 (degassing agent) can favorably reduce the compression deflection coefficient.

[0080] Examples 1 to 6 achieved a plant-based content of 10% or more and a compression deflection coefficient of 2.8 or less. Example 1 also achieved a plant-based content of 10% or more and had good physical properties as a seat pad.

[0081] 4. Effects of Examples According to the above examples, the use of plant-derived polyols contributed to the thinning of products.

[0082] The present disclosure is not limited to the above-described embodiments, and various modifications and variations are possible within the scope of the present disclosure.

[0083] 110...Seat pad

Claims

1. A polyurethane foam obtained from a composition containing a polyol and an isocyanate, wherein the polyol contains a plant-derived polyol, and the polyurethane foam has a compressive deflection coefficient of 2.8 or less as measured in accordance with JIS K6400-2:2012 Method E.

2. The polyurethane foam according to claim 1, wherein the plant-derived polyol is a polyol having a hydroxyl value of 40 mg KOH / g or more and 130 mg KOH / g or less.

3. A polyurethane foam according to claim 1 or 2, wherein the composition contains a silicone-based foam stabilizer having a viscosity of 900 mPa·s (25°C) or less and a surface tension of 24 mN / m or less.

4. A polyurethane foam according to claim 1 or 2, wherein the proportion of plant-derived substances in the entire composition (plant content) is 10% or more.

5. The polyurethane foam of claim 1 or claim 2, wherein the composition comprises a polyol having an ethylene oxide unit content of greater than 50% by weight.

6. A seat pad comprising the polyurethane foam according to claim 1 or 2.

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