Polyol composition and polyurethane foam obtained using the same

Abstract

An object of the present invention is to provide a polyol composition which, despite using a biomass-derived polyester polyol, has high miscibility with a polyisocyanate and is capable of producing a flexible polyurethane foam having high flexibility and appropriate compression hardness.　 The present invention relates to a polyol composition characterized by including a polyester polyol and a polyether polyol.　The polyester polyol is a reaction product of raw material compounds including:　 a rosin (a) including a resin acid (a1) having a conjugated double bond;　 a biomass-derived fatty acid (b) including an unsaturated fatty acid (b1);　 an α,β-unsaturated carboxylic acid (c);　 an aliphatic saturated polycarboxylic acid (d); and　 a polyol (p) including a diol (p1) having an ether bond.　

Description

POLYOL COMPOSITION AND POLYURETHANE FOAM OBTAINED USING THE SAME

[0001] The present invention relates to a polyol composition and a polyurethane foam obtained using the same.

[0002] Since a flexible polyurethane foam has high flexibility, it has been conventionally used as a cushioning material in a variety of applications.　Examples of the applications include cushioning materials for household uses and vehicles, such as a pillow, a mattress, a chair, and a seat.

[0003] A flexible polyurethane foam is produced by reacting a polyol and a polyisocyanate in the presence of a foaming agent.　A polyether polyol is used as such a polyol.

[0004] PTL 1: Japanese Patent Application Laid-Open No. 2014-162813

[0005] When a polyether polyol is used, a flexible polyurethane foam having high flexibility can be obtained.　Thus, when a user sits or lies down on the flexible polyurethane foam and applies the load to the flexible polyurethane foam, the flexible polyurethane foam undergoes compressive deformation to fit the user's body shape, and as a result, the user sinks into the flexible polyurethane foam.　This allows the user to use the flexible polyurethane foam comfortably as a cushioning material.

[0006] However, since a conventional flexible polyurethane foam has too low compression hardness, there is a problem in that the user sinks too far into the flexible polyurethane foam, causing the user to feel the hardness of a support that supports the flexible polyurethane foam.　Such a problem is also known as a "bottoming feeling".　The support is constituted by a highly rigid member made of metal, a non-foamed synthetic resin, or the like to support the flexible polyurethane foam.　Thus, when the above-mentioned problem occurs, the user feels pain or discomfort as if the support is in direct contact with the user without benefiting from the flexibility provided by the flexible polyurethane foam.

[0007] For the user to comfortably use the flexible polyurethane foam as a cushioning material, as described above, the flexible polyurethane foam needs to have high flexibility and appropriate compression hardness.　However, the flexibility and compression hardness of the flexible polyurethane foam are in a trade-off relationship, and it is difficult even for a person skilled in the art to achieve both.

[0008] The use of a polyester polyol in addition to a polyether polyol as a polyol constituting the flexible polyurethane foam can appropriately enhance the compression hardness of the flexible polyurethane foam.

[0009] On the other hand, in recent years, issues such as global warming and depletion of fossil resources have been drawing much attention.　From such a viewpoint, it is desirable to produce the flexible polyurethane foam using a polyol derived from biomass.　Examples of the biomass-derived polyol that can be used include a biomass-derived polyester polyol that is a reaction product of a polyol and an acid component derived from biomass, such as rosin or a fatty acid.

[0010] However, the biomass-derived polyester polyol has a problem of having high viscosity and low miscibility with a polyisocyanate.　Thus, the use of the biomass-derived polyester polyol may reduce the miscibility of a polyol composition including the biomass-derived polyester polyol and the polyether polyol with the polyisocyanate.

[0011] When the miscibility of the polyol composition with the polyisocyanate is low, it becomes difficult to uniformly mix the polyol composition and the polyisocyanate.　This makes it difficult to foam the polyol composition with a foaming agent at the time of the reaction with the polyisocyanate, and in some cases, it is not possible to produce a flexible polyurethane foam.　Further, even if the flexible polyurethane foam can be produced, the flexible polyurethane foam includes a part where the polyol composition and the polyisocyanate have not been uniformly mixed.　The flexible polyurethane foam having such a part becomes brittle and cannot be elastically deformed.　As a result, when a load is applied to the flexible polyurethane foam, the flexible polyurethane foam is compressed and undergoes plastic deformation, making it difficult for the flexible polyurethane foam to recover its original shape after the load is released.

[0012] Thus, there is a need for the polyol composition that uses the biomass-derived polyester polyol and yet maintains high miscibility with the polyisocyanate.

[0013] An object of the present invention is to provide a polyol composition which, despite using a biomass-derived polyester polyol, has high miscibility with a polyisocyanate and is capable of producing a flexible polyurethane foam having high flexibility and appropriate compression hardness.

[0014] The present inventors have conducted various studies in view of the above-mentioned problems and found that the above-mentioned problems can be solved by the following polyol composition.

[0015] The present invention relates to a polyol composition including a polyester polyol and a polyether polyol, in which the polyester polyol is a reaction product of raw material compounds including: 　　　 a rosin (a) including a resin acid (a1) having a conjugated double bond; 　　　 a biomass-derived fatty acid (b) including an unsaturated fatty acid (b1); 　　　 an α,β-unsaturated carboxylic acid (c); 　　　 an aliphatic saturated polycarboxylic acid (d); and 　　　 a polyol (p) including a diol (p1) having an ether bond.

[0016] According to the present invention, it is possible to provide the polyol composition which, despite using the biomass-derived polyester polyol, has high miscibility with the polyisocyanate and is capable of producing the flexible polyurethane foam having high flexibility and appropriate compression hardness.

[0017] Fig. 1 is a schematic diagram illustrating an example of a force-displacement curve in a test for measuring the compressive strength of a polyurethane foam to explain a yield point (P).

[0018] In the numerical ranges described in stages in this specification, the upper or lower limit of a certain numerical range can be arbitrarily combined with the upper or lower limit of the numerical range of another stage.

[0019] In the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in an example or a value that can be unambiguously derived from an example. In this specification, a numerical value connected with "to" means a numerical range including the numerical values before and after "to" as the lower and upper limits.

[0020] <Polyol composition> 　　　 A polyol composition of the present invention includes a polyester polyol and a polyether polyol.

[0021] The polyester polyol includes a reaction product of raw material compounds including: 　　　 a rosin (a) including a resin acid (a1) having a conjugated double bond; 　　　 a biomass-derived fatty acid (b) including an unsaturated fatty acid (b1); 　　　 an α,β-unsaturated carboxylic acid (c); 　　　 an aliphatic saturated polycarboxylic acid (d); and 　　　 a polyol (p) including a diol (p1) having an ether bond.

[0022] The polyester polyol is preferably a reaction product of raw material compounds including: 　　　 a rosin (a) including a resin acid (a1) having a conjugated double bond; 　　　 a biomass-derived fatty acid (b) including an unsaturated fatty acid (b1); 　　　 an α,β-unsaturated carboxylic acid (c); 　　　 an aliphatic saturated polycarboxylic acid (d); and 　　　 a polyol (p) including a diol (p1) having an ether bond.

[0023] In general, the polyester polyol can be produced by, for example, dehydration condensation of a polyvalent carboxylic acid and a polyhydric alcohol.　In the polyester polyol of the present invention, the rosin (a) including the resin acid (a1) having a conjugated double bond and the biomass-derived fatty acid (b) including the unsaturated fatty acid (b1) are used as the biomass-derived raw materials.　Since the rosin (a) and the biomass-derived fatty acid (b) are monocarboxylic acids, it is difficult to use them directly as the polycarboxylic acids serving as the raw materials for producing the polyester polyol.

[0024] Thus, in the present invention, the α,β-unsaturated carboxylic acid (c) is added to each of the rosin (a) and the biomass-derived fatty acid (b) by a Diels-Alder reaction or an ene reaction to obtain a polycarboxylic acid having multiple carboxy groups.　Furthermore, the above-mentioned carboxy groups are subjected to an esterification reaction with hydroxyl groups of the polyol (p) to obtain the polyester polyol.　As described above, this polyester polyol is produced using the rosin (a) and the biomass-derived fatty acid (b), and thus it is qualified as a biomass-derived polyester polyol.

[0025] The use of the polyester polyol can appropriately enhance the compression hardness of the polyurethane foam.　However, due to the molecular structures of the rosin (a) and the biomass-derived fatty acid (b), the polyester polyol has high viscosity and low miscibility with the polyisocyanate.　Thus, the biomass-derived polyester polyol reduces the miscibility of the polyol composition, which includes the biomass-derived polyester polyol and the polyether polyol, with the polyisocyanate.　As a result, this polyester polyol may make it difficult to produce the polyurethane foam or cause weakening of the polyurethane foam.

[0026] Thus, in the present invention, the aliphatic saturated polycarboxylic acid (d) is further used as the raw material compound for the polyester polyol.　When the aliphatic saturated polycarboxylic acid (d) is subjected to an esterification reaction with the polyol (p), it is possible to lower the viscosity of the polyester polyol while maintaining high miscibility with the polyisocyanate.　This allows the polyol composition to maintain high miscibility with the polyisocyanate, making it possible to mix the polyol composition and the polyisocyanate uniformly.　Such a polyol composition can be easily foamed with a foaming agent at the time of the reaction with the polyisocyanate, making it possible to more reliably produce the polyurethane foam.　Furthermore, this polyol composition prevents the occurrence of a part where the polyol composition and the polyisocyanate are not uniformly mixed in the polyurethane foam. This also makes it possible to prevent the polyurethane foam from becoming brittle.　Thus, when a load is applied to the polyurethane foam, the compressed polyurethane foam undergoes elastic deformation without experiencing plastic deformation, allowing the polyurethane foam to recover its original shape once the load is released.

[0027] When the biomass-derived polyester polyol as described above is used in combination with the polyether polyol, the polyol composition of the present invention has high miscibility with the polyisocyanate despite the use of the biomass-derived polyester polyol, making it possible to produce a flexible polyurethane foam having high flexibility and appropriate compression hardness.

[0028] In the present invention, the term "biomass" refers to an organic resource derived from a living organism or a plant, excluding a resource derived from a fossil.　Examples of the biomass include wood, seaweed, animal carcass and excrement, and plankton.

[0029] The term "biomass-derived" means that a raw material is at least partially made using an organic resource derived from a living organism or a plant, and excludes a raw material produced solely from a resource derived from a fossil.

[0030] In contrast, a raw material made using only a fossil-derived resource without using an organic resource derived from a living organism or a plant is defined as a raw material "derived from fossil resource".　Examples of the fossil-derived resource include coal, petroleum, and natural gas.

[0031] <Polyester polyol> 　　　 The polyol composition of the present invention includes the polyester polyol and the polyether polyol.　The polyester polyol is a reaction product of the raw material compounds including the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) as described above.　The raw material compounds constituting the polyester polyol of the present invention will be described one by one below.

[0032] (Rosin (a)) 　　　 The rosin (a) is derived from biomass and is used as the raw material compound for constituting the polyester polyol.　The rosin (a) is generally obtained by distilling a resin oil of a plant and removing a volatile component.　Examples of the plant resin oil include a pine resin included in a plant of the pine family.　Examples of the volatile component include turpentine oil.

[0033] The rosin (a) is a rosin monomer (monomer acid).　Thus, polymerized rosin is excluded from the rosin (a).　That is, the rosin (a) does not include a rosin polymer such as a rosin dimer (a dimer acid).

[0034] The rosin (a) includes a resin acid (a1) having a conjugated double bond.　The resin acid (a1) having a conjugated double bond preferably has 12 or more carbon atoms, more preferably 15 or more carbon atoms, and more preferably 18 or more carbon atoms.　The resin acid (a1) having a conjugated double bond preferably has 35 or less carbon atoms, more preferably 30 or less carbon atoms, and more preferably 25 or less carbon atoms.　The resin acid (a1) having a conjugated double bond is preferably a monocarboxylic acid having one carboxy group in the molecule.

[0035] The α,β-unsaturated carboxylic acid (c) can be added to the conjugated double bond of the resin acid (a1) by the Diels-Alder reaction.　Thus, the conjugated double bond of the resin acid (a1) is preferably at least one of an s-cis type conjugated double bond or a conjugated double bond that can be isomerized to the s-cis type conjugated double bond.　Among these, the s-cis type conjugated double bond is more preferable.　Examples of the conjugated double bond that can be isomerized to the s-cis type conjugated double bond include an s-trans type conjugated double bond that can be isomerized to the s-cis type conjugated double bond.　The term "s-cis type conjugated double bond" refers to a conjugated double bond having a conformation where two double bonds are on the same sides (cis type) in reference to a single bond (s) connecting the two double bonds in the conjugated double bond.　The term "s-trans type conjugated double bond" refers to a conjugated double bond having a conformation where two double bonds are on the opposite sides (trans type) in reference to a single bond (s) connecting the two double bonds in the conjugated double bond.　It is preferable that a double bond included in an aromatic ring structure be excluded from the conjugated double bond included in the resin acid (a1).　Furthermore, it is preferable that the resin acid (a1) having a conjugated double bond does not include an aromatic resin acid.

[0036] Examples of the resin acid (a1) having a conjugated double bond include an alicyclic resin acid such as abietic acid, neoabietic acid, palustric acid, and levopimaric acid.　Among these, levopimaric acid is preferable. Because levopimaric acid has an s-cis conformation, it has excellent reactivity with α,β-unsaturated carboxylic acid (c).　The resin acid (a1) having a conjugated double bond may be used singly or in combination of two or more types thereof.

[0037] Furthermore, abietic acid, neoabietic acid, and palustric acid can be easily isomerized to levopimaric acid by heating, for example, at the time of the reaction with an α,β-unsaturated carboxylic acid (c).　Thus, levopimaric acid obtained by isomerizing abietic acid, neoabietic acid, and palustric acid can be used.　That is, levopimaric acid may be at least one of isomers of abietic acid, neoabietic acid, and palustric acid.　Levopimaric acid is preferably at least one of isomers of abietic acid, neoabietic acid, and palustric acid.

[0038] It is preferable that abietic acid, neoabietic acid, and palustric acid be isomerized to levopimaric acid by heating.　The heating temperature is preferably 150 to 300°C, more preferably 175 to 200°C.

[0039] The content of the resin acid (a1) having a conjugated double bond in the rosin (a) is preferably 25% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, and more preferably 55% by mass or more.　Furthermore, the content of the resin acid (a1) having a conjugated double bond in the rosin (a) is preferably 100% by mass or less, more preferably 90% by mass or less, more preferably 80% by mass or less, and more preferably 70% by mass or less.

[0040] The rosin (a) preferably includes a resin acid (a2) which is at least one of an alicyclic resin acid having no conjugated double bond or an aromatic resin acid.　The number of carbon atoms of the resin acid (a2) is preferably 12 or more, more preferably 15 or more, and more preferably 18 or more.　The number of carbon atoms of the resin acid (a2) is preferably 35 or less, more preferably 30 or less, and more preferably 25 or less.　The resin acid (a2) is preferably a monocarboxylic acid having one carboxy group in the molecule.

[0041] Examples of the resin acid (a2) include an alicyclic resin acid having no conjugated double bond, such as pimaric acid, isopimaric acid, or sandaracopimaric acid, and an aromatic resin acid such as dehydroabietic acid.　Among these, pimaric acid, isopimaric acid, and dehydroabietic acid are preferable, and pimaric acid and dehydroabietic acid are more preferable.　The resin acid (a2) may be used singly or in combination of two or more types thereof.

[0042] The content of the resin acid (a2) in the rosin (a) is preferably 1% by mass or more, more preferably 10% by mass or more, and more preferably 20% by mass or more.　Furthermore, the content of the resin acid (a2) in the rosin (a) is preferably 75% by mass or less, more preferably 60% by mass or less, more preferably 50% by mass or less, more preferably 45% by mass or less, more preferably 40% by mass or less, and more preferably 35% by mass or less.

[0043] Examples of the rosin (a) including the resin acid (a1) having a conjugated double bond include biomass-derived rosin, such as gum rosin, tall oil rosin, or wood rosin.　Among these, tall oil rosin is preferable.　The biomass-derived rosin may be used singly or in combination of two or more types thereof.

[0044] The content of the rosin (a) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 1% by mass or more, more preferably 5% by mass or more, more preferably 7% by mass or more, and more preferably 10% by mass or more.　The content of the rosin (a) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 35% by mass or less, more preferably 25% by mass or less, and more preferably 23% by mass or less.　The rosin (a) contained in an amount of the above-mentioned lower limit value or more can appropriately enhance the compressive strength of the polyurethane foam.　The rosin (a) contained in an amount of the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol, and furthermore, can maintain the tear strength of the polyurethane foam.

[0045] (Biomass-derived fatty acid (b)) 　　　 The biomass-derived fatty acid (b) is used as a raw material compound for constituting the polyester polyol.　The biomass-derived fatty acid (b) includes an unsaturated fatty acid (b1).　This unsaturated fatty acid (b1) is also derived from biomass.

[0046] The biomass-derived fatty acid (b) is a monomer of a fatty acid (monomer acid).　Thus, a polymerized fatty acid is excluded from the biomass-derived fatty acid (b).　That is, the biomass-derived fatty acid (b) does not include a polymer of an unsaturated fatty acid, such as a dimer of an unsaturated fatty acid (a dimer acid).

[0047] The biomass-derived fatty acid (b) is an aliphatic monocarboxylic acid having one carboxyl group at the end of a linear or branched hydrocarbon chain.　Examples of the biomass-derived fatty acid (b) include an aliphatic monocarboxylic acid represented by R-COOH (where R is a linear or branched, saturated or unsaturated monovalent hydrocarbon group).

[0048] Examples of the unsaturated fatty acid (b1) include an aliphatic monocarboxylic acid represented by R1-COOH (where R1is a linear or branched monovalent unsaturated hydrocarbon group).

[0049] The number of carbon atoms of the unsaturated fatty acid (b1) is preferably 12 or more, more preferably 14 or more, and more preferably 16 or more.　The number of carbon atoms of the unsaturated fatty acid (b1) is preferably 30 or less, and more preferably 25 or less.

[0050] Examples of the unsaturated fatty acids (b1) include myristoleic acid, palmitoleic acid, oleic acid, vaccenic acid, eicosenoic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, and arachidonic acid.　As the unsaturated fatty acid (b1), palmitoleic acid, oleic acid, and linoleic acid are preferable, and oleic acid and linoleic acid are more preferable.　The unsaturated fatty acid (b1) may be used singly or in combination of two or more types thereof.

[0051] The content of the unsaturated fatty acid (b1) in the biomass-derived fatty acid (b) is preferably 50% by mass or more, and more preferably 70% by mass or more.　Furthermore, the content of the unsaturated fatty acid (b1) in the biomass-derived fatty acid (b) is preferably 100% by mass or less, more preferably 97% by mass or less, more preferably 95% by mass or less, and more preferably 93% by mass or less.

[0052] The biomass-derived fatty acid (b) preferably includes a saturated fatty acid (b2).　Examples of the saturated fatty acid (b2) include an aliphatic monocarboxylic acid represented by R2-COOH (where R2is a linear or branched monovalent saturated hydrocarbon group).

[0053] Examples of the saturated fatty acid (b2) include octanoic acid (caprylic acid), nonanoic acid, decanoic acid (capric acid), dodecanoic acid (lauric acid), tetradecanoic acid (myristic acid), hexadecanoic acid (palmitic acid), heptadecanoic acid (margaric acid), octadecanoic acid (stearic acid), eicosanoic acid (arachidic acid), docosanoic acid (behenic acid), and tetracosanoic acid.　Among these, palmitic acid, heptadecanoic acid, and stearic acid are preferable.　The saturated fatty acid (b2) may be used singly or in combination of two or more types thereof.

[0054] The content of the saturated fatty acid (b2) in the biomass-derived fatty acid (b) is preferably 0.1% by mass or more, more preferably 1% by mass or more, more preferably 2% by mass or more, more preferably 3% by mass or more, and more preferably 5% by mass or more.　Furthermore, the content of the saturated fatty acid (b2) in the biomass-derived fatty acid (b) is preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass or less.

[0055] Examples of the above-mentioned biomass-derived fatty acid (b) include a linseed oil fatty acid, a tung oil fatty acid, a castor oil fatty acid, a soybean oil fatty acid, a tall oil fatty acid, a rice bran oil fatty acid, a palm oil fatty acid, a coconut oil fatty acid, a dehydrated castor oil fatty acid, a sunflower oil fatty acid, a rapeseed oil fatty acid, a canola oil fatty acid, and a cottonseed oil fatty acid.　Among these, a tall oil fatty acid is preferable.　The biomass-derived fatty acid (b) may be used singly or in combination of two or more types thereof.

[0056] The content of the biomass-derived fatty acid (b) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 5% by mass or more, more preferably 7% by mass or more, more preferably 10% by mass or more, more preferably 12% by mass or more, and more preferably 14% by mass or more.　The content of the biomass-derived fatty acid (b) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 35% by mass or less, more preferably 30% by mass or less, more preferably 26% by mass or less, and more preferably 24% by mass or less.　The biomass-derived fatty acid (b) contained in an amount of the above-mentioned lower limit value or more can appropriately enhance the compressive strength of the polyurethane foam.　The biomass-derived fatty acid (b) contained in an amount of the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol.

[0057] In the raw material compounds of the polyester polyol, the mass ratio [(a) / (b)] of the rosin (a) relative to the biomass-derived fatty acid (b) is more preferably 0.12 or more, more preferably 0.25 or more, and more preferably 0.50 or more.　In the raw material compounds of the polyester polyol, the mass ratio [(a) / (b)] of the rosin (a) relative to the biomass-derived fatty acid (b) is preferably 2.00 or less, more preferably 1.50 or less, and more preferably 1.00 or less.　Setting the above-mentioned mass ratio [(a) / (b)] to the above-mentioned lower limit value or more can appropriately enhance the compressive strength of the polyurethane foam.　Setting the above-mentioned mass ratio [(a) / (b)] to the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol.

[0058] (α,β-unsaturated carboxylic acid (c)) 　　　 The α,β-unsaturated carboxylic acid (c) is used as the raw material compound for constituting the polyester polyol.　The α,β-unsaturated carboxylic acid (c) is added to each of the rosin (a) and the biomass-derived fatty acid (b) described above by a Diels-Alder reaction or an ene reaction.　Thus, a carboxy group can be introduced into each of the rosin (a) and the biomass-derived fatty acid (b).　As a result, the rosin (a) and the biomass-derived fatty acid (b) can be introduced into the molecular structure of the polyester polyol.　The α,β-unsaturated carboxylic acid (c) is preferably an α,β-unsaturated aliphatic carboxylic acid.

[0059] Examples of the α,β-unsaturated carboxylic acid (c) include an α,β-unsaturated dicarboxylic acid (c1) and an α,β-unsaturated monocarboxylic acid (c2).　Among these, an α,β-unsaturated dicarboxylic acid (c1) is preferable.　The α,β-unsaturated carboxylic acid (c) may be used singly or in combination of two or more types thereof.

[0060] The α,β-unsaturated carboxylic acid (c) preferably contains an α,β-unsaturated dicarboxylic acid (c1).　The α,β-unsaturated dicarboxylic acid (c1) has an unsaturated bond.　Thus, α,β-unsaturated dicarboxylic acid (c1) can serve as a dienophile in a Diels-Alder reaction and also serves as an enophile in an ene reaction.　Examples of the unsaturated bonds include a carbon-carbon double bond and a carbon-carbon triple bond.　Among these, a carbon-carbon double bond is preferable.　The α,β-unsaturated dicarboxylic acid (c1) is preferably an α,β-unsaturated aliphatic dicarboxylic acid.

[0061] The number of carbon atoms of the α,β-unsaturated dicarboxylic acid (c1) is preferably 3 or more, and more preferably 4 or more.　The number of carbon atoms of the α,β-unsaturated dicarboxylic acid (c1) is preferably 10 or less, more preferably 8 or less, and more preferably 5 or less.

[0062] Examples of the α,β-unsaturated dicarboxylic acid (c1) include an α,β-unsaturated dicarboxylic acid and an anhydride thereof.　An α,β-unsaturated aliphatic dicarboxylic acid and an anhydride thereof are preferable.　Specific examples thereof include fumaric acid, itaconic acid, maleic acid, mesaconic acid, citraconic acid, and anhydrides thereof.　Among these, maleic acid and maleic anhydride are preferable, and maleic anhydride is more preferable.　As the α,β-unsaturated dicarboxylic acid (c1), itaconic acid, mesaconic acid, citraconic acid, or an anhydride thereof formed by thermal decomposition of citric acid can also be used.　The α,β-unsaturated dicarboxylic acid (c1) may be used singly or in combination of two or more types thereof.

[0063] The content of the α,β-unsaturated dicarboxylic acid (c1) in the α,β-unsaturated carboxylic acid (c) is preferably 50% by mass or more, more preferably 80% by mass or more, more preferably 98% by mass or more, and more preferably 99% by mass or more.　The content of the α,β-unsaturated dicarboxylic acid (c1) in the α,β-unsaturated carboxylic acid (c) is preferably 100% by mass or less.

[0064] The α,β-unsaturated carboxylic acid (c) may contain an α,β-unsaturated monocarboxylic acid (c2).　The α,β-unsaturated monocarboxylic acid (c2) is preferably an α,β-unsaturated aliphatic monocarboxylic acid.

[0065] The number of carbon atoms of the α,β-unsaturated monocarboxylic acid (c2) is preferably 10 or less, more preferably 8 or less, and more preferably 5 or less.　The number of carbon atoms of the α,β-unsaturated monocarboxylic acid (c2) is preferably 3 or more.　Examples of the α,β-unsaturated monocarboxylic acid (c2) include an α,β-unsaturated monocarboxylic acid and an anhydride thereof.　An α,β-unsaturated aliphatic monocarboxylic acid and an anhydride thereof are preferred.　Specific examples thereof include acrylic acid, methacrylic acid, and crotonic acid.　The α,β-unsaturated monocarboxylic acid (c2) may be used singly or in combination of two or more types thereof.

[0066] In the raw material compounds of the polyester polyol, the mass ratio [(c) / (a)] of the α,β-unsaturated carboxylic acid (c) to the rosin (a) is preferably 0.15 or more, more preferably 0.30 or more, more preferably 0.45 or more, and more preferably 0.50 or more.　In the raw material compounds of the polyester polyol, the mass ratio [(c) / (a)] of the α,β-unsaturated carboxylic acid (c) to the rosin (a) is preferably 2.00 or less, more preferably 1.50 or less, more preferably 0.90 or less, more preferably 0.65 or less, and more preferably 0.51 or less.

[0067] In the raw material compounds of the polyester polyol, the mass ratio [(c) / (a + b)] of the α,β-unsaturated carboxylic acid (c) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.05 or more, more preferably 0.10 or more, more preferably 0.17 or more, and more preferably 0.20 or more.　In the raw material compounds of the polyester polyol, the mass ratio [(c) / (a + b)] of the α,β-unsaturated carboxylic acid (c) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.45 or less, more preferably 0.30 or less, more preferably 0.27 or less, and more preferably 0.24 or less.　Setting the mass ratio [(c) / (a + b)] to the above-mentioned upper limit value or less can appropriately enhance the compressive strength of the polyurethane foam.

[0068] The content of the α,β-unsaturated carboxylic acid (c) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 3.0% by mass or more, more preferably 5.0% by mass or more, more preferably 6.0% by mass or more, and more preferably 6.5% by mass or more.　The content of the α,β-unsaturated carboxylic acid (c) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 15.0% by mass or less, more preferably 12.0% by mass or less, more preferably 10.0% by mass or less, more preferably 9.0% by mass or less, and more preferably 8.5% by mass or less.　The α,β-unsaturated carboxylic acid (c) contained in an amount of the above-mentioned lower limit value or more can introduce a sufficient amount of the carboxy group into the rosin (a) and the biomass-derived fatty acid (b).　The α,β-unsaturated carboxylic acid (c) contained in an amount of the above-mentioned upper limit value or less can appropriately enhance the compressive strength of the polyurethane foam.

[0069] (Aliphatic saturated polycarboxylic acid (d)) 　　　 The aliphatic saturated polycarboxylic acid (d) is used as the raw material compound for constituting the polyester polyol.　The use of the aliphatic saturated polycarboxylic acid (d) can help to reduce the viscosity of the polyester polyol and enhance the miscibility with the polyisocyanate.　Furthermore, the aliphatic saturated polycarboxylic acid (d) can form a large number of ester bonds in the polyester polyol by a reaction with the polyol (p).　The moiety containing the ester bond can act as a flexible segment in the polyurethane foam.　As a result, an excessive increase in the compressive strength of the polyurethane foam (decrease in flexibility) and weakening of the polyurethane foam can be suppressed.

[0070] The number of carbon atoms of the aliphatic saturated polycarboxylic acid (d) is preferably 3 or more, more preferably 4 or more, and more preferably 6 or more.　The number of carbon atoms of the aliphatic saturated polycarboxylic acid (d) is preferably 15 or less, more preferably 11 or less, and more preferably 10 or less.　The aliphatic saturated polycarboxylic acid (d) having the number of carbon atoms within the above-mentioned range can form a large number of ester bonds in the polyester polyol.

[0071] Examples of the aliphatic saturated polycarboxylic acid (d) include an aliphatic saturated dicarboxylic acid represented by HOOC-R3-COOH (wherein R3is a linear alkylene group), and an anhydride thereof.　Such an aliphatic saturated dicarboxylic acid can lower the degree of branching of the polyester polyol, maintain the flexibility of the polyurethane foam, and suppress the polyurethane foam from becoming brittle.　The aliphatic saturated polycarboxylic acid (d) may be used singly or in combination of two or more types thereof.

[0072] Examples of the aliphatic saturated dicarboxylic acid include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.　Among these, adipic acid and sebacic acid are preferable, and adipic acid is more preferable.　The aliphatic saturated dicarboxylic acids may be used singly or in combination of two or more.

[0073] The aliphatic saturated polycarboxylic acid (d) is preferably a monomer of an aliphatic saturated polycarboxylic acid.　Therefore, the polymerized fatty acid (e2) is preferably excluded from the aliphatic saturated polycarboxylic acid (d).

[0074] In the raw material compounds of the polyester polyol, the mass ratio [(d) / (a + b)] of the aliphatic saturated polycarboxylic acid (d) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.05 or more, more preferably 0.10 or more, more preferably 0.17 or more, more preferably 0.22 or more, and more preferably 0.25 or more.　Setting the mass ratio [(d) / (a + b)] to the above-mentioned lower limit value or more can make it possible to reduce the viscosity of the polyester polyol and suppress the weakening of the polyurethane foam.

[0075] In the raw material compounds of the polyester polyol, the mass ratio [(d) / (a + b)] of the aliphatic saturated polycarboxylic acid (d) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.85 or less, more preferably 0.70 or less, more preferably 0.50 or less, and more preferably 0.45 or less.　Setting the mass ratio [(d) / (a + b)] to the above-mentioned upper limit value or less can enhance the air permeability of the polyurethane foam.

[0076] The content of the aliphatic saturated polycarboxylic acid (d) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 5% by mass or more, more preferably 7% by mass or more, and more preferably 7.5% by mass or more.　The content of the aliphatic saturated polycarboxylic acid (d) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 15% by mass or less.　The aliphatic saturated polycarboxylic acid (d) contained in an amount of the above-mentioned lower limit value or more can make it possible to reduce the viscosity of the polyester polyol and suppress the weakening of the polyurethane foam.　The aliphatic saturated polycarboxylic acid (d) contained in an amount of the above-mentioned upper limit value or less can enhance the air permeability of the polyurethane foam.

[0077] (Polymerized acid (e)) 　　　 The raw material compounds of the polyester polyol preferably further contain a polymerized acid (e).　The polymerized acid (e) is preferably a multimer obtained by multimerizing, such as dimerizing, an acid compound.　Examples of the polymerized acid (e) include a polymerized rosin (e1) and a polymerized fatty acid (e2).

[0078] The raw material compounds of the polyester polyol preferably further include at least one of a polymerized rosin (e1) or a polymerized fatty acid (e2).　Thus, the polyester polyol preferably includes a polyester polyol that is a reaction product of raw material compounds including, 　　　 a rosin (a) including a resin acid (a1) having a conjugated double bond; 　　　 a biomass-derived fatty acid (b) including an unsaturated fatty acid (b1); 　　　 an α,β-unsaturated carboxylic acid (c); 　　　 an aliphatic saturated polycarboxylic acid (d); 　　　 a polyol (p) including a diol (p1) having an ether bond; and 　　　 at least one of a polymerized rosin (e1) or a polymerized fatty acid (e2).

[0079] The use of the polymerized rosin (e1) and the polymerized fatty acid (e2) can help to promote the communication of bubbles during the foaming process.　This makes it possible to enhance the air permeability of the polyurethane foam.　As a result, it is possible to prevent from becoming stuffy at the contact part between a user and the polyurethane foam, thereby alleviating the discomfort of the user due to stuffiness.

[0080] The raw material compounds of the polyester polyol may include both the polymerized rosin (e1) and the polymerized fatty acid (e2), and may include only one of them: either the polymerized rosin (e1) or the polymerized fatty acid (e2).　From the viewpoint of enhancing the compressive strength of the polyurethane foam, the polymerized rosin (e1) is preferable.　From the viewpoint of enhancing the tear strength of the polyurethane foam, the polymerized fatty acid (e2) is preferable.

[0081] The polymerized rosin (e1) is obtained by polymerizing a rosin with each other.　The polymerized rosin (e1) is a multimer of a rosin, such as a dimer of a rosin (a dimer acid).　The polymerized rosin (e1) may contain only one type of multimer of a rosin, but the polymerized rosin (e1) generally contains a plurality of types of multimers of a rosin.　The polymerized rosin (e1) preferably contains a dimer of a rosin (a dimer acid).

[0082] The content of the dimer of a rosin in the polymerized rosin (e1) is preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 98% by mass or more, and more preferably 100% by mass.　That is, the polymerized rosin (e1) is more preferably the dimer of a rosin.

[0083] The rosin (monomer) used as the raw material of the polymerized rosin (e1) is the same as that described above for the rosin (a), and thus a detailed description thereof is omitted here.

[0084] The polymerized rosin (e1) can be produced using known methods.　As a method for producing the polymerized rosin (e1), for example, a method in which a monomer of a rosin is polymerized in the presence of a catalyst while being heated may be used.　Examples of the catalysts include an acidic compound such as sulfuric acid, formic acid, p-toluenesulfonic acid, methanesulfonic acid, hydrogen fluoride, zinc chloride, aluminum chloride, and titanium tetrachloride.　The polymerization of the monomer of a rosin is preferably carried out in a solvent.　The heating temperature is preferably 40 to 160°C.　The polymerization time is preferably 1 to 5 hours.　If necessary, impurities and unreacted rosin monomers can be removed by distillation.

[0085] In the raw material compounds of the polyester polyol, the mass ratio [(e1) / (a + b)] of the polymerized rosin (e1) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.02 or more, more preferably 0.04 or more, more preferably 0.06 or more, and more preferably 0.07 or more.　Setting the mass ratio [(e1) / (a + b)] to the above-mentioned lower limit value or more can enhance the air permeability of the polyurethane foam.

[0086] In the raw material compounds of the polyester polyol, the mass ratio [(e1) / (a + b)] of the polymerized rosin (e1) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.20 or less, more preferably 0.16 or less, more preferably 0.13 or less, and more preferably 0.11 or less.　Setting the mass ratio [(e1) / (a + b)] to the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol.

[0087] The content of the polymerized rosin (e1) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), the polymerized rosin (e1), and the polyol (p) is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, more preferably 1.7% by mass or more, and more preferably 2.3% by mass or more.　The polymerized rosin (e1) contained in an amount of the above-mentioned lower limit value or more can enhance the air permeability of the polyurethane foam.

[0088] The content of the polymerized rosin (e1) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), the polymerized rosin (e1), and the polyol (p) is preferably 10% by mass or less, more preferably 7% by mass or less, more preferably 5% by mass or less, and more preferably 4% by mass or less.　The polymerized rosin (e1) contained in an amount of the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol.

[0089] The polymerized fatty acid (e2) is obtained by polymerizing an unsaturated fatty acid with each other.　The polymerized fatty acid (e2) is a multimer of an unsaturated fatty acid, such as a dimer of an unsaturated fatty acid (a dimer acid).　Examples of the unsaturated fatty acid include myristoleic acid, palmitoleic acid, oleic acid, bacsenic acid, eicosenoic acid, linoleic acid, α-linolenic acid, γ-linolenic acid, and arachidonic acid.　As the unsaturated fatty acid, palmitoleic acid, oleic acid, and linoleic acid are preferable, and oleic acid and linoleic acid are more preferable.

[0090] The polymerized fatty acid (e2) preferably contains a dimer of an unsaturated fatty acid (a dimer acid).　The polymerized fatty acid (e2) preferably contains a dimer of oleic acid and a dimer of linoleic acid.　The polymerized fatty acid (e2) may contain only one type of multimer of an unsaturated fatty acid, however the polymerized fatty acid (e2) generally contains a plurality of types of multimers of unsaturated fatty acids.

[0091] The content of the dimer of an unsaturated fatty acid in the polymerized fatty acid (e2) is preferably 70% by mass or more, more preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 98% by mass or more, and more preferably 100% by mass.

[0092] The unsaturated fatty acid (monomer) used as the raw material for the polymerized fatty acid (e2) is the same as those described above for the unsaturated fatty acid (b1), and thus a detailed description thereof will be omitted here.

[0093] The polymerized fatty acid (e2) can be produced using known methods.　As a method for producing the polymerized fatty acid (e2), for example, a method in which an unsaturated fatty acid that serves as a monomer is polymerized in the presence of a catalyst while being heated may be used.　Examples of the catalysts include clays such as bentonite and montmorillonite.　The heating temperature is preferably 250 to 350°C.

[0094] In the raw material compounds of the polyester polyol, the mass ratio [(e2) / (a + b)] of the polymerized fatty acid (e2) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.01 or more, more preferably 0.30 or more, more preferably 0.50 or more, more preferably 0.60 or more, and more preferably 0.65 or more.　Setting the mass ratio [(e2) / (a + b)] to the above-mentioned lower limit value or more can enhance the air permeability of the polyurethane foam.

[0095] In the raw material compounds of the polyester polyol, the mass ratio [(e2) / (a + b)] of the polymerized fatty acid (e2) relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 2.00 or less, more preferably 1.50 or less, more preferably 1.00 or less, more preferably 0.85 or less, and more preferably 0.75 or less.　Setting the mass ratio [(e2) / (a + b)] to the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol.

[0096] The content of the polymerized fatty acid (e2) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), the polymerized fatty acid (e2), and the polyol (p) is preferably 5.0% by mass or more, more preferably 9.0% by mass or more, more preferably 12.0% by mass or more, more preferably 14.0% by mass or more, and more preferably 15.0% by mass or more.　The polymerized fatty acid (e2) contained in an amount of the above-mentioned lower limit value or more can enhance the air permeability of the polyurethane foam.

[0097] The content of the polymerized fatty acid (e2) relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), the polymerized fatty acid (e2), and the polyol (p) is preferably 30.0% by mass or less, more preferably 23.0% by mass or less, more preferably 19.0% by mass or less, more preferably 17.0% by mass or less, and more preferably 16.0% by mass or less.　The polymerized fatty acid (e2) contained in an amount of the above-mentioned upper limit value or less can reduce the viscosity of the polyester polyol.

[0098] (Polyol (p)) 　　　 The polyol (p) is used as the raw material compound for constituting the polyester polyol.　The polyol (p) includes a diol (p1) having an ether bond.　The use of the diol (p1) having an ether bond can help to reduce the degree of branching of the polyester polyol.　Thus, high flexibility of the polyurethane foam can be maintained.

[0099] Examples of the diol (p1) having an ether bond include an aliphatic diol having an ether bond.　Examples of the aliphatic diol having an ether bond include a polyalkylene glycol such as diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, and polypropylene glycol, and a copolymer of ethylene glycol and propylene glycol; and an alkanediol such as 1,2-ethylene glycol, 1,3-propanediol, and 1,3-butanediol.　Among these, polyalkylene glycol is preferable, and triethylene glycol, polyethylene glycol, and tripropylene glycol are more preferable.　Triethylene glycol is more preferable.

[0100] In the polyalkylene glycol, the number of repeating oxyalkylene units is, for example, 2 or more.　From the viewpoint of suppressing the weakening of the polyurethane foam, the number of repeating oxyalkylene units in the polyalkylene glycol is preferably 3 or more.

[0101] The diol (p1) having an ether bond may be used singly or in combination of two or more types thereof.　For example, the diol (p1) having an ether bond may include triethylene glycol in combination with polyethylene glycol or polypropylene glycol.

[0102] When the diol (p1) having an ether bond is a polymer (e.g., polyethylene glycol, polypropylene glycol, etc.), the number-average molecular weight of the diol (p1) having an ether bond is preferably 100 or more, more preferably 120 or more, more preferably 140 or more, more preferably 150 or more, and more preferably 170 or more.　When the diol (p1) having an ether bond is a polymer (e.g., polyethylene glycol, polypropylene glycol, etc.), the number-average molecular weight of the diol (p1) having an ether bond is preferably 1,000 or less, more preferably 750 or less, more preferably 500 or less, more preferably 400 or less, and more preferably 300 or less.

[0103] When the diol (p1) having an ether bond is a polymer, the number-average molecular weight of the diol (p1) having an ether bond is a polystyrene-equivalent value measured by a GPC (gel permeation chromatography) method.

[0104] The hydroxyl value of the the diol (p1) having an ether bond is preferably 150 mgKOH / g or more, more preferably 180 mgKOH / g or more, more preferably 300 mgKOH / g or more, more preferably 400 mgKOH / g or more, and more preferably 500 mgKOH / g or more.　The hydroxyl value of the diol (p1) having an ether bond is preferably 2,000 mgKOH / g or less, more preferably 1,500 mgKOH / g or less, more preferably 1,000 mgKOH / g or less, and more preferably 800 mgKOH / g or less.

[0105] The hydroxyl value of the diol (p1) having an ether bond can be measured in accordance with ASTM D4274-16C.　When the diol (p1) having an ether bond contains a plurality of types of diols (p1), the hydroxyl value of the diol (p1) having an ether bond is defined as a hydroxyl value obtained by weighted average of the hydroxyl values of the individual diols (p1) based on the content (% by mass) of the individual diols (p1).

[0106] In the raw material compounds of the polyester polyol, the mass ratio [(p1) / (a + b)] of the diol (p1) having an ether bond relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 0.30 or more, more preferably 0.50 or more, more preferably 0.80 or more, more preferably 0.90 or more, and more preferably 1.00 or more.　Setting the mass ratio [(p1) / (a + b)] to the above-mentioned lower limit value or more can reduce the acid value of the polyester polyol.

[0107] In the raw material compounds of the polyester polyol, the mass ratio [(p1) / (a + b)] of the diol (p1) having an ether bond relative to the total amount of the rosin (a) and the biomass-derived fatty acid (b) is preferably 2.50 or less, more preferably 2.00 or less, more preferably 1.50 or less, and more preferably 1.45 or less.　Setting the mass ratio [(p1) / (a+b)] to the above-mentioned upper limit value or less can enhance the flexibility of the polyurethane foam.

[0108] The content of the diol (p1) having an ether bond relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the diol (p1) having an ether bond is preferably 20% by mass or more, more preferably 30% by mass or more, more preferably 35% by mass or more, more preferably 38% by mass or more, and more preferably 40% by mass or more.　The diol (p1) having an ether bond contained in an amount of the above-mentioned lower limit value or more can reduce the acid value of the polyester polyol.

[0109] The content of the diol (p1) having an ether bond relative to the total mass of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the diol (p1) having an ether-bond is preferably 70% by mass or less, more preferably 60% by mass or less, more preferably 55% by mass or less, more preferably 53% by mass or less, and more preferably 50% by mass or less.　The diol (p1) having an ether bond contained in an amount of the above-mentioned upper limit value or less can enhance the flexibility of the polyurethane foam.

[0110] The content of the diol (p1) having an ether bond in the polyol (p) is more preferably 50% by mass or more, more preferably 70% by mass or more, more preferably 85% by mass or more, more preferably 90% by mass or more, more preferably 95% by mass or more, more preferably 98% by mass or more, and more preferably 100% by mass.　That is, the polyol (p) is more preferably the diol (p1) having an ether bond.

[0111] The polyol (p) may contain a trivalent or higher-valence polyol (p2).　The trivalent or higher-valence polyol (p2) is preferably an aliphatic polyol with a valence of three or higher.　Examples thereof include glycerin, trimethylolethane, trimethylolpropane, erythritol, diglycerin, pentaerythritol, sorbitol, sorbitan, and dipentaerythritol.　Among these, an aliphatic polyol having 3 to 12 carbon atoms is preferable.　Glycerin, trimethylolethane, and trimethylolpropane are more preferable, and glycerin is more preferable.　The polyol (p2) may be used singly or in combination of two or more types thereof.

[0112] The content of the trivalent or higher-valence polyol (p2) in the polyol (p) is more preferably 10% by mass or less, more preferably 5% by mass or less, more preferably 1% by mass or less, more preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and more preferably 0% by mass.　From the viewpoint of maintaining high flexibility of the polyurethane foam, the content of the trivalent or higher-valence polyol (p2) is preferably low, and it is more preferable that the polyol (p) does not contain the trivalent or higher-valence polyol (p2).

[0113] (Aromatic polycarboxylic acid) 　　　 The raw material compounds of the polyester polyol may further contain an aromatic polycarboxylic acid.　Examples of the aromatic polycarboxylic acid include an aromatic polycarboxylic acid and an anhydride thereof.　Specific examples thereof include orthophthalic acid, isophthalic acid, terephthalic acid, naphthalene dicarboxylic acid, biphenyl dicarboxylic acid, trimellitic acid, pyromellitic acid, and anhydrides of these.　Among these, orthophthalic acid, isophthalic acid, terephthalic acid, and anhydrides of these are preferable, and isophthalic acid and orthophthalic anhydride are more preferable.　The aromatic polycarboxylic acid (e) may be used singly or in combination of two or more.

[0114] The content of the aromatic polycarboxylic acid in the raw material compounds of the polyester polyol is more preferably 5% by mass or less, more preferably 1% by mass or less, more preferably 0.5% by mass or less, more preferably 0.1% by mass or less, and more preferably 0% by mass.　From the viewpoint of maintaining high flexibility of the polyurethane foam, the content of the aromatic polycarboxylic acid is preferably low, and it is more preferable that the raw material compounds do not contain the aromatic polycarboxylic acid.

[0115] The polyester polyol contains an ester bond.　The number of ester bonds per molecule in the polyester polyol is preferably more than 3, and more preferably 4 or more.

[0116] As described above, the polyester polyol of the present invention is a reaction product of the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p).　The rosin (a) and the fatty acid (b) are each derived from biomass and are reacted with the α,β-unsaturated carboxylic acid (c) to introduce them into the molecular structure of the polyester polyol.

[0117] Specifically, the rosin (a) includes the resin acid (a1) having a conjugated double bond.　The biomass-derived fatty acid (b) includes the unsaturated fatty acid (b1).　Therefore, when they are reacted with the α,β-unsaturated carboxylic acid (c), the α,β-unsaturated carboxylic acid (c) is added to the resin acid (a1) by a Diels-Alder reaction to form an adduct.　In addition, the α,β-unsaturated carboxylic acid (c) is added to the unsaturated fatty acid (b1) by a Diels-Alder reaction or an ene reaction to form an adduct.

[0118] The polyester polyols of the present invention includes units derived from the adducts described above.　Examples of the units derived from the adducts described above include a unit (I) derived from the adduct obtained by adding the α,β-unsaturated carboxylic acid (c) to the resin acid (a1), and a unit (II) derived from the adduct obtained by adding the α,β-unsaturated carboxylic acid (c) to the unsaturated fatty acid (b1).

[0119] The unit (I) is preferably a unit derived from an adduct obtained by adding maleic acid or maleic anhydride to levopimaric acid by a Diels-Alder reaction.　Levopimaric acid may be at least one isomer of abietic acid, neoabietic acid, and palustric acid.　The unit (II) is preferably at least one of a unit derived from an adduct obtained by adding maleic acid or maleic anhydride to oleic acid by an ene reaction, or a unit derived from an adduct obtained by adding maleic acid or maleic anhydride to linoleic acid by a Diels-Alder reaction.　It is more preferable that the unit (II) be both of the above units.

[0120] As described above, a Diels-Alder reaction or an ene reaction using the α,β-unsaturated carboxylic acid (c) enables the introduction of the rosin (a) and the biomass-derived fatty acid (b) into the molecular structure of the polyester polyol.

[0121] Furthermore, a plurality of carboxyl groups derived from the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), and the aliphatic saturated polycarboxylic acid (d) used as the raw material compounds of the polyester polyol are subjected to a condensation reaction with the hydroxyl groups of the polyol (p) to form ester bonds, thereby obtaining the polyester polyol.

[0122] (Method for producing polyester polyol) 　　　 A method for producing the polyester polyol of the present invention includes a step of obtaining the polyester polyol by reacting raw material compounds including: 　　　 the rosin (a) including the resin acid (a1) having a conjugated double bond; 　　　 the biomass-derived fatty acid (b) including the unsaturated fatty acid (b1); 　　　 the α,β-unsaturated carboxylic acid (c); 　　　 the aliphatic saturated polycarboxylic acid (d); and 　　　 the polyol (p) including the diol (p1) having an ether bond.

[0123] The reaction of the raw material compounds of the polyester polyol is preferably performed by heating the raw material compounds.　The heating temperature is preferably 150 to 300°C.　Heating promotes the above-mentioned Diels-Alder reaction, ene reaction, and esterification reaction to obtain the polyester polyol.　Note that the reaction of the raw material compounds may be performed while inert gas such as nitrogen is blown into the reaction system.

[0124] The reaction of the raw material compounds may be performed in the presence of a catalyst for promoting the Diels-Alder reaction or the ene reaction, or a catalyst for promoting the esterification reaction.　The Diels-Alder reaction or the ene reaction can be easily promoted by heating the raw material compounds.　Thus, it is not necessary to use the catalyst for promoting the Diels-Alder reaction or the ene reaction.　Examples of the catalyst for promoting the esterification reaction include lithium acetate and magnesium acetate.　Each catalyst may be used singly or in combination of two or more types thereof.

[0125] The order of reacting the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and the polyol (p) is not particularly limited.　For example, the following synthesis methods (I) to (III) can be mentioned.

[0126] (Synthesis method (I)) 　　　 First, the rosin (a) and the fatty acid derived from biomass (b) are subjected to a Diels-Alder reaction or an ene reaction with the α,β-unsaturated carboxylic acid (c) to obtain their adducts.　Next, the above-mentioned adducts are esterified with the aliphatic saturated polycarboxylic acid (d), the polyol (p), and, if necessary, at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2) to obtain the polyester polyol.

[0127] (Synthesis method (II)) 　　　 First, the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), and, if necessary, at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2), are esterified with the polyol (p) to obtain an esterified product.　Next, the above-mentioned esterified product is subjected to a Diels-Alder reaction or an ene reaction with the rosin (a) and the biomass-derived fatty acid (b) to obtain the polyester polyol.

[0128] (Synthesis method (III)) 　　　 The polyester polyol can be obtained by mixing the rosin (a), the biomass-derived fatty acid (b), the α,β-unsaturated carboxylic acid (c), the aliphatic saturated polycarboxylic acid (d), the polyol (p), and, if necessary, at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2) and, by simultaneously performing a Diels-Alder reaction or an ene reaction and the esterification reaction.

[0129] The above-mentioned synthesis method (I) is preferable.　According to the above-mentioned synthesis method (I), it is possible to provide an appropriate branched structure to the polyester polyol and enhance the reactivity with the polyisocyanate.　This synthesis method (I) makes it possible to shorten the reaction time with the polyisocyanate.

[0130] The method for producing the polyester polyol using the above-mentioned synthesis method (I) first includes a step (I-1) of subjecting the rosin (a) including the resin acid (a1) having a conjugated double bond and the biomass-derived fatty acid (b) including the unsaturated fatty acid (b1) to the Diels-Alder reaction or the ene reaction with the α,β-unsaturated carboxylic acid (c).

[0131] In the step (I-1), an adduct of the resin acid (a1) and the α,β-unsaturated carboxylic acid (c), and an adduct of the unsaturated fatty acid (b1) and the α,β-unsaturated carboxylic acid (c) are obtained by the Diels-Alder reaction or the ene reaction.

[0132] In the step (I-1), it is preferable to perform the Diels-Alder reaction or the ene reaction by heating the rosin (a) including the resin acid (a1) having a conjugated double bond, the biomass-derived fatty acid (b) including the unsaturated fatty acid (b1), and the α,β-unsaturated carboxylic acid (c).　The heating temperature is preferably 175 to 200°C.

[0133] Note that, in the step (I-1), the Diels-Alder reaction or the ene reaction may be performed in the presence of at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2).　Since the polymerized rosin (e1) and the polymerized fatty acid (e2) have a bulky structure, they are not subjected to the Diels-Alder reaction or the ene reaction due to steric hindrance.　Thus, in the step (I-1), when the Diels-Alder reaction or the ene reaction is performed in the presence of the polymerized rosin (e1) and the polymerized fatty acid (e2), a mixture of the above-mentioned adducts and at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2) is obtained.

[0134] The method for producing the polyester polyol using the above-mentioned synthesis method (I) next includes a step (I-2) of obtaining a polyester polyol by esterifying the adduct of the resin acid (a1) and the α,β-unsaturated carboxylic acid (c) and the adduct of the unsaturated fatty acid (b1) and the α,β-unsaturated carboxylic acid (c) with the aliphatic saturated polycarboxylic acid (d), the polyol (p) including the diol (p1) having an ether bond, and, if necessary, at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2).

[0135] In the step (I-2), the esterification reaction is preferably performed by heating the above-mentioned adducts, the aliphatic saturated polycarboxylic acid (d), the polyol (p), and, if necessary, at least one of the polymerized rosin (e1) or the polymerized fatty acid (e2).　The heating temperature is preferably 245 to 255°C.

[0136] In the present invention, the rosin (a) and the biomass-derived fatty acid (b) can be introduced into the molecular structure of the polyester polyol by a Diels-Alder reaction or an ene reaction using the α,β-unsaturated carboxylic acid (c).　The rosin (a) and the fatty acid (b) are both derived from biomass.　Thus, the polyester polyol of the present invention can achieve a high bio-regeneration rate.

[0137] The polyester polyol preferably has a low hydroxyl value and a high number-average molecular weight.　In the polyurethane foam, a moiety containing the urethane bond acts as a hard segment portion because cohesive force due to hydrogen bonding is generated.　In order to maintain the high flexibility of the polyurethane foam, it is preferable to use a polyester polyol having a low hydroxyl value and a high number-average molecular weight to lower the density of the urethane bond.

[0138] Specifically, the polyester polyol preferably has a hydroxyl value of 200 mgKOH / g or less and a number-average molecular weight of 500 or more.　The polyester polyol having such a low hydroxyl value and a high number-average molecular weight can reduce the density of the urethane bond formed in the polyurethane foam.

[0139] The hydroxyl value of the polyester polyol is preferably 200 mgKOH / g or less, more preferably 175 mgKOH / g or less, more preferably 150 mgKOH / g or less, and more preferably 135 mgKOH / g or less.　In addition, the hydroxyl value of the polyether polyol is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, more preferably 40 mgKOH / g or more, more preferably 50 mgKOH / g or more, and more preferably 70 mgKOH / g or more.　The polyester polyol having the hydroxyl value of the above-mentioned upper limit value or less can allow the polyurethane foam to maintain high flexibility.　The polyester polyol having the hydroxyl value of the above-mentioned lower limit value or more can impart an appropriate compressive strength to the polyurethane foam.　As a result, when a user sits or lies down on the polyurethane foam and applies the load to the polyurethane foam, it can prevent the user from excessively sinking into the polyurethane foam.

[0140] The hydroxyl value of the polyester polyol can be measured in accordance with ASTM D4274-16C.

[0141] When a plurality of types of polyester polyols are used, the hydroxyl value of the polyester polyol is defined as a hydroxyl value obtained by weighted average of hydroxyl values of the individual polyester polyols based on the content (% by mass) of the individual polyester polyols.　Specifically, the weighted average of the hydroxyl values is obtained by the following formula. 　　　 Weighted average hydroxyl value (mgKOH / g) = [H1× W1+ H2× W2+ ・・・ + Hn× Wn] / 100 　　　 (In the formula, n represents the number of types of polyester polyols, Hnis the hydroxyl value (mgKOH / g) of the n-th type of polyester polyol, and Wnis the mass percentage (% by mass) of the n-th type of polyester polyol.)

[0142] The number-average molecular weight (Mn) of the polyester polyol is preferably 500 or more, more preferably 600 or more, and even more preferably 800 or more.　The number-average molecular weight (Mn) of the polyester polyol is preferably 3,000 or less, more preferably less than 3,000, more preferably 2,900 or less, more preferably 2,000 or less, more preferably 1,700 or less, and more preferably 1,500 or less.　The polyester polyol with the number-average molecular weight (Mn) of the above-mentioned lower limit value or more can enhance the tear strength of the polyurethane foam.　The polyester polyol with the number-average molecular weight (Mn) of the above-mentioned upper limit value or less can increase the air permeability of the polyurethane foam.

[0143] The number-average molecular weight (Mn) of the polyester polyol is a polystyrene-equivalent value measured by size-exclusion chromatography (SEC).　The measurement conditions for SEC are as follows. 　　　 Eluent: Tetrahydro furan solution containing 0.02% by volume of acetic acid 　　　 Flow rate of eluent: 1 mL / min 　　　 Column (stationary phase): Agilent PLGel Mixed B column x 3 　　　 Standard material: polystyrene (molecular weight: 580 to 6,500,000 g / mol) 　　　 Column temperature: 30°C

[0144] The viscosity of the polyester polyol at 23°C is preferably 20.0 Pa・s or less, more preferably 15.0 Pa・s or less, more preferably 10.0 Pa・s or less, more preferably 6.0 Pa・s or less, and more preferably 5.0 Pa・s or less.　In the present invention, as described above, the use of the aliphatic polycarboxylic acid (d) can help to keep the viscosity of the biomass-derived polyester polyol low.　This configuration can enhance the miscibility of the polyol composition containing the polyester polyol with the polyisocyanate, and it is possible to uniformly mix the polyisocyanate with the polyisocyanate.　The viscosity of the polyester polyol at 23°C is preferably 0.001 Pa・s or more, and preferably 0.01 Pa・s or more.

[0145] The low-viscosity polyester polyol enables the polyol composition to achieve a viscosity suitable for forming open cells when reacted with the polyisocyanate in the presence of a foaming agent.　Therefore, a high content of open cells can result in a polyurethane foam with enhanced flexibility and air permeability.

[0146] The viscosity of the polyester polyol at 23°C is measured by the following measurement apparatus and measurement conditions. 　　　 - Measuring device: Rotary rheometer (e.g., product name "MCR 92 type rheometer" manufactured by Anton Paar GmbH) 　　　 - Geometry: Cone plate with a cone diameter of 25 mm 　　　 - Shear rate: 25 [s-1]

[0147] The content of the polyester polyol in the polyol composition is preferably 1 part by mass or more, more preferably 5 parts by mass or more, more preferably 10 parts by mass or more, more preferably 15 parts by mass or more, and more preferably 20 parts by mass or more, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol.　The content of the polyester polyol in the polyol composition is preferably 50 parts by mass or less, more preferably 45 parts by mass or less, more preferably 40 parts by mass or less, more preferably 35 parts by mass or less, and more preferably 30 parts by mass or less, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol.　The polyester polyol contained in an amount of the above-mentioned lower limit value or more can enhance the compression hardness and the air permeability of the polyurethane foam.　The polyester polyol contained in an amount of the above-mentioned upper limit value or less can maintain the flexibility of the polyurethane foam.

[0148] <Polyether polyol> 　　　 The polyol composition of the present invention further include a polyether polyol in addition to the polyester polyol described above.　The use of the polyether polyol can impart high flexibility to the polyurethane foam.

[0149] The number of ester bonds per molecule in the polyether polyol is preferably 3 or less, and more preferably 0.　That is, it is more preferable that the polyether polyol does not contain an ester bond.

[0150] The raw material compound of the polyether polyol preferably does not contain at least one of the rosin (a) or the biomass-derived fatty acid (b), and preferably does not contain both the rosin (a) and the biomass-derived fatty acid (b).　That is, the polyether polyol preferably does not contain at least one of the unit derived from the rosin (a) or the unit derived from the biomass-derived fatty acid (b), and preferably does not contain both the unit derived from the rosin (a) and the unit derived from the biomass-derived fatty acid (b).

[0151] Examples of the polyether polyol include a polyoxyalkylene polyol.　The polyoxyalkylene polyol is obtained by ring-opening addition polymerization of an alkylene oxide to an initiator having two or more active hydrogen atoms within one molecule.

[0152] Examples of the initiator include an aliphatic polyhydric alcohol, an aliphatic amine, and an aromatic amine.　Among these, an aliphatic polyhydric alcohol is preferred.　Using this initiator can maintain high flexibility of the polyurethane foam.　The initiators may be used singly or in combination of two or more types thereof.

[0153] Examples of the aliphatic polyhydric alcohol include an aliphatic dihydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, neopentyl glycol, cyclohexylene glycol, and cyclohexanedimethanol; an aliphatic trihydric alcohol such as trimethylolpropane, and glycerine; and an aliphatic tetrahydric alcohol such as pentaerythritol.　Among these, an aliphatic trihydric alcohol is preferable, and glycerin is more preferable.　The aliphatic polyhydric alcohol may be used singly or in combination of two or more.

[0154] Examples of the alkylene oxide include ethylene oxide, propylene oxide, and butylene oxide.　Among these, ethylene oxide and propylene oxide are preferable.　The alkylene oxide may be used singly or in combination of two or more.

[0155] The polyoxyalkylene polyol preferably contains an alkylene oxide unit, more preferably contains at least one of an ethylene oxide unit or a propylene oxide unit, and more preferably contains both an ethylene oxide unit and a propylene oxide unit.　Such a polyoxyalkylene polyol can achieve a polyether polyol having high compatibility with the polyester polyol.

[0156] In the polyether polyol, the content of the ethylene oxide unit is preferably 0 to 50% by mass, and more preferably 5 to 30% by mass.

[0157] In the polyether polyol, the content of the propylene oxide unit is preferably 50 to 100% by mass, and more preferably 70 to 95% by mass.

[0158] More preferably, the polyoxyalkylene polyol does not contain an ester bond.　The polyoxyalkylene polyol preferably does not contain at least one of the unit derived from the rosin (a) or the unit derived from the biomass-derived fatty acid (b), and preferably does not contain both the unit derived from the rosin (a) and the unit derived from the biomass-derived fatty acid (b).

[0159] The hydroxyl value of the polyether polyol is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, more preferably 30 mgKOH / g or more, and more preferably 40 mgKOH / g or more.　The hydroxyl value of the polyether polyol is preferably 200 mgKOH / g or less, more preferably 150 mgKOH / g or less, more preferably 100 mgKOH / g or less, more preferably 80 mgKOH / g or less, and more preferably 60 mgKOH / g or less.

[0160] As a method for measuring a hydroxyl value of the polyether polyol, a method similar to the method for measuring a hydroxyl value of the polyester polyol described above can be adopted.

[0161] The number-average molecular weight (Mn) of the polyether polyol is preferably 500 or more, more preferably 1,000 or more, more preferably 2,000 or more, and more preferably 3,000 or more.　The number-average molecular weight (Mn) of the polyether polyol is preferably 20,000 or less, more preferably 10,000 or less, more preferably 6,000 or less, and more preferably 4,000 or less.

[0162] As a method for measuring a number-average molecular weight (Mn) of the polyether polyol, a method similar to the method for measuring a number-average molecular weight (Mn) of the polyester polyol described above can be adopted.

[0163] The viscosity of the polyether polyol at 23°C is preferably 20.0 Pa・s or less, more preferably 15.0 Pa・s or less, 10.0 Pa・s or less, more preferably 5.0 Pa・s or less, more preferably 3.0 Pa・s or less, and more preferably 1.5 Pa・s or less.　The viscosity of the polyether polyol at 23°C is preferably 0.001 Pa・s or more, and preferably 0.01 Pa・s or more.

[0164] As a method for measuring a viscosity of the polyether polyol at 23°C, a measurement method similar to that of the polyester polyol at 23°C described above can be adopted.

[0165] The content of the polyether polyol in the polyol composition is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, more preferably 60 parts by mass or more, more preferably 65 parts by mass or more, and more preferably 70 parts by mass or more, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol.　The content of the polyether polyol in the polyol composition is preferably 99 parts by mass or less, more preferably 95 parts by mass or less, more preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and more preferably 80 parts by mass or less, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol.　The polyether polyol contained in an amount of the above-mentioned lower limit value or more can enhance the flexibility of the polyurethane foam.　The polyether polyol contained in an amount of the above-mentioned upper limit value or less can suppress a decrease in compression hardness of the polyurethane foam.

[0166] The hydroxyl value of the polyol composition is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, more preferably 40 mgKOH / g or more, and more preferably 50 mgKOH / g or more.　The hydroxyl value of the polyol composition is preferably 150 mgKOH / g or less, more preferably 100 mgKOH / g or less, more preferably 85 mgKOH / g or less, and more preferably 75 mgKOH / g or less.

[0167] As a method for measuring the hydroxyl value of the polyol composition, a method similar to the method for measuring a hydroxyl value of the polyester polyol described above can be adopted.

[0168] The polyol composition may include a solvent.　Examples of the solvent include benzene, toluene, xylene, mesitylene, chlorobenzene, o-dichlorobenzene, methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, trichloroethylene, tetrachloroethane, tetrachloroethylene, tetrahydrofuran, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, dimethylsulfoxide, and sulfolane.　Among these, toluene, xylene, and dimethyl sulfoxide are preferable.　The solvents may be used singly or in combination of two or more types thereof.

[0169] The polyol composition may include any other polyol in addition to the polyester polyol and polyether polyol described above.　The other polyol may be any polyol commonly used for producing a polyurethane foam.　Examples of the other polyol include a polylactone polyol, a polycarbonate polyol, and a polymer polyol.　The other polyol may be used singly or in combination of two or more.

[0170] The other polyol may be either a biomass-derived polyol or a fossil resource-derived polyol.

[0171] When the other polyol is used, the content of the other polyol in the polyol composition is preferably 30% by mass or less, more preferably 20% by mass or less, and more preferably 10% by mass or less.

[0172] The polyol composition may include a catalyst or an additive.　Examples of the catalyst include a urethanization catalyst and a trimerization catalyst.　Examples of the additive include a flame retardant, a foam stabilizer, an antioxidant, a heat stabilizer, a metal deactivator, an antistatic agent, a stabilizer, a lubricant, a softener, a pigment, and a dye.　Each of the catalyst and the additive may be used singly or in combination of two or more.　The detailed description for the catalyst is the same as that for a polyurethane foam catalyst described later.

[0173] <Polyurethane foam> 　　　 The present invention provides a polyurethane foam.　The polyurethane foam is a foam of a foamable composition containing the polyol composition as described above, a polyisocyanate, and a foaming agent.

[0174] The polyurethane foam includes a urethane resin having a urethane bond formed by the reaction of the polyisocyanate with the polyester polyol and the polyether polyol included in the polyol composition.

[0175] (Polyisocyanate) 　　　 The foamable composition includes a polyisocyanate.　A polyisocyanate has two or more isocyanate groups (-NCO) within one molecule.

[0176] Examples of the polyisocyanate include an aliphatic polyisocyanate, an alicyclic polyisocyanate, and an aromatic polyisocyanate.　Among these, an aromatic polyisocyanate is preferable.　The polyisocyanate may be used singly or in combination of two or more.

[0177] Examples of the aromatic polyisocyanate include toluene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), and polymethylene polyphenylene polyisocyanate (PMDI).　Among these, toluene diisocyanate and diphenylmethane diisocyanate are preferable, and toluene diisocyanate is more preferable.

[0178] In order to prevent the polyurethane foam from becoming brittle, the number of isocyanate groups per molecule of the polyisocyanate is preferably 2.10 or less, more preferably 2.05 or less, and more preferably 2.00.

[0179] (Foaming agent) 　　　 The foamable composition includes a foaming agent.　Examples of the foaming agent include water.　The foaming agent is preferably water.　The content of water in the foaming agent is preferably 90% by mass or more, more preferably 95% by mass or more, and more preferably 100% by mass.

[0180] The foaming agent may further contain any other foaming agent in addition to water.　Examples of the other foaming agents include a hydrocarbon, a hydrofluoroolefin, a hydrochlorofluorocarbon, a hydrofluorocarbon, a hydrochlorocarbon, and a chlorofluorocarbon.　The foaming agent may be used singly or in combination of two or more types thereof.

[0181] Examples of the hydrocarbon include propane, butane, n-pentane, isopentane, hexane, heptane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, and cycloheptane.　The hydrocarbon may be used singly or in combination of two or more.　The content of the hydrocarbon in the foaming agent is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 1% by mass or less.

[0182] Examples of the hydrofluoroolefin include HFO-1336mzz (Z) (cis-1,1,1,4,4,4-hexafluorobut-2-ene), HFO-1234yf (2,3,3,3-tetrafluoro-1-propene), HFO-1224yd (Z) (trans-1-chloro-2,3,3,3-tetrafluoropropene), HFO-1233zd (E) (trans-1-chloro-3,3,3-trifluoropropene), and HFO-1224yd (Z) (trans-1-chloro-2,3,3,3-tetrafluoropropene).　The hydrofluoroolefin may be used singly or in combination of two or more thereof.　The content of the hydrofluoroolefin in the foaming agent is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 1% by mass or less.

[0183] The content of the foaming agent in the foamable composition is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, more preferably 2 parts by mass or more, and more preferably 3 parts by mass or more, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.　The content of the foaming agent in the foamable composition is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, more preferably 6 parts by mass or less, and more preferably 4 parts by mass or less, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.

[0184] (urethanization catalyst) 　　　 The foamable composition preferably includes a urethanization catalyst to promote the reaction to form a urethane bond.

[0185] Examples of the urethanization catalyst include an amine-based catalyst, an ammonium salt-based catalyst, an organopotassium salt-based catalyst, and an organometallic catalyst.　Among these, an amine-based catalyst and an organometallic catalyst are preferable.　Examples of the organometallic catalyst include di(2-ethylhexanoate)tin(II).　The urethanization catalyst may be used singly or in combination of two or more kinds thereof.

[0186] The content of the amine-based catalyst in the foamable composition is preferably 0.05 parts by mass or more, more preferably 0.15 parts by mass or more, and more preferably 0.25 parts by mass or more, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.　The content of the amine-based catalyst in the foamable composition is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and more preferably 1 part by mass or less, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.

[0187] The content of the organometallic catalyst in the foamable composition is preferably 0.05 parts by mass or more, more preferably 0.08 parts by mass or more, and more preferably 0.10 parts by mass or more, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.　The content of the organometallic catalyst in the foamable composition is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and more preferably 1 part by mass or less, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.

[0188] (Trimerization Catalyst) 　　　 The foamable composition may include a trimerization catalyst to promote the formation of an isocyanurate ring.　A trimerization reaction of the isocyanate group forms an isocyanurate ring.

[0189] Examples of the trimerization catalyst include a carboxylic acid salt such as an alkali metal salt of a carboxylic acid and a quaternary ammonium salt of a carboxylic acid.　Among these, an alkali metal salt of a carboxylic acid is preferable.　Examples of the alkali metal salt of a carboxylic acid include potassium acetate and potassium 2-ethylhexanoate.　The trimerization catalyst may be used singly or in combination of two or more kinds thereof.

[0190] (Foam stabilizer) 　　　 The foamable composition may include a foam stabilizer.

[0191] Examples of the foam stabilizer include a silicone surfactan such as an organopolysiloxane, an organopolysiloxane-polyoxyalkylene copolymer, a polyalkenylsiloxane having a polyoxyalkylene side chain, and a silicone-grease copolymer.　The foam stabilizer may be used singly or in combination of two or more types thereof.　The content of the foam stabilizer in the foamable composition is preferably 0.4 to 5 parts by mass, and more preferably 0.6 to 2 parts by mass, relative to 100 parts by mass of the total amount of the polyester polyol and the polyether polyol contained in the polyol composition.

[0192] The foamable composition may include other additives.　Examples of the other additives include an antioxidant, a heat stabilizer, a metal deactivator, an antistatic agent, a stabilizer, a lubricant, a softener, a flame retardant, a pigment, and a dye.

[0193] The foamable composition includes the polyol composition, a polyisocyanate, and a foaming agent.　The foamable composition is obtained by mixing the polyol composition with the polyisocyanate and the foaming agent.

[0194] The isocyanate index of the foamable composition is preferably 80 or more, more preferably 90 or more, more preferably 95 or more, and more preferably 100 or more.　The isocyanate index of the foamable composition is preferably 250 or less, more preferably 200 or less, more preferably 150 or less, more preferably 130 or less, more preferably 125 or less, and more preferably 110 or less.　Setting the isocyanate index to the above-mentioned lower limit value or more can form a polyurethane foam that is difficult to crush by being stable in the three-dimensional direction.　Setting the isocyanate index to the above-mentioned upper limit value or less can form a polyurethane foam having high flexibility.

[0195] The isocyanate index of the foamable composition can be calculated by the following formula. 　　　 Isocyanate index = 100 × (equivalent number of isocyanate groups in polyisocyanate) / (equivalent number of active hydrogen groups in polyol + equivalent number of active hydrogen groups in water)

[0196] The equivalent number of isocyanate groups in the polyisocyanate can be calculated using the following formula. 　　　 Equivalent number of isocyanate groups in polyisocyanate = 100 × content (% by mass) of isocyanate groups in polyisocyanate × mixing amount (g) of polyisocyanate / molecular weight of isocyanate group (42 g / mol)

[0197] The equivalent number of active hydrogen groups in the polyol can be calculated based on the following formula. 　　　 Equivalent number of active hydrogen groups in polyol = (W1× H1 / 56100) + (W2× H2 / 56100) +・・・+ (Wm× Hm / 56100) (In the formula, Wmis the content (g) of the m-th type of polyol in the total polyols included in the foamable composition, Hmis the hydroxyl value (mgKOH / g) of the m-th type of polyol, and m is an integer representing the number of types of polyols included in the foamable composition.)

[0198] Furthermore, the hydroxyl value of the m-th type of polyol can be measured in accordance with ASTM D4274-16C.

[0199] The equivalent number of active hydrogen groups in water can be calculated based on the following formula.　When the foamable composition includes water as a foaming agent, the equivalent number of active hydrogen groups in water needs to be taken into consideration when the isocyanate index of the foamable composition is calculated. 　　　 Equivalent number of active hydrogen groups in water = water mixing amount (g) × 2 / 18

[0200] The open cell rate of the polyurethane foam is preferably 75% or more, more preferably 85% or more, more preferably 95% or more, and more preferably 100%.　Setting the open cell rate to the above-mentioned lower limit value or more can obtain the polyurethane foam having high flexibility and air permeability.

[0201] The open cell rate (%) of the polyurethane foam can be measured in accordance with ASTM D6226-15.

[0202] The closed cell rate of the polyurethane foam is preferably 25% or less, more preferably 15% or less, more preferably 5% or less, and more preferably 0%.　Setting the closed cell rate to the above-mentioned upper limit value or less can obtain the polyurethane foam having high flexibility and air permeability.

[0203] Note that the closed cell rate of the polyurethane foam can be calculated based on the following formula. 　　　 In the following formula, the open cell rate of the polyurethane foam can be measured in accordance with ASTM D6226-15. 　　　 Closed cell rate (%) of polyurethane foam = 100 - [open cell rate (%) of polyurethane foam]

[0204] The density of the polyurethane foam is preferably 12 kg / m3or more, more preferably 20 kg / m3or more, and more preferably 26 kg / m3or more.　The density of the polyurethane foam is preferably 80 kg / m3or less, more preferably 45 kg / m3or less, and more preferably 32 kg / m3or less.

[0205] The density of the polyurethane foam can be measured in accordance with ASTM D1622-14.

[0206] The compressive strength in the 40% thickness direction of the polyurethane foam is preferably 4.0 kPa or more, more preferably 4.2 kPa or more, and more preferably 4.4 kPa or more.　The compressive strength in the 40% thickness direction of the polyurethane foam is preferably 10.0 kPa or less, more preferably 7.5 kPa or less, and more preferably 6.0 kPa or less.　Setting the compressive strength in the 40% thickness direction to be within the above-mentioned range can allow the polyurethane foam to be used comfortably as a cushioning material.　Setting the compressive strength in the 40% thickness direction to the above-mentioned lower limit value or more allows the polyurethane foam to have appropriate compressive strength.　This configuration makes it possible to prevent the user from sinking too far into the polyurethane foam when the user sits or lies down on the polyurethane foam and applies the load to the flexible polyurethane foam.　Thus, a user can use the polyurethane foam comfortably without feeling the hardness of the support that supports the polyurethane foam.　Setting the compressive strength in the 40% thickness direction to the above-mentioned upper limit value or less allows the polyurethane foam to have high flexibility.　This configuration causes the polyurethane foam to compressively deform to fit the user's body shape and allows the user to sink moderately into the polyurethane foam.

[0207] The compressive strength (kPa) in the 40% thickness direction of the polyurethane foam is the compressive strength measured in accordance with European Standard EN 826:2013, except that the dimensions of the test specimen is 50 mm in width, 50 mm in length, and 30 mm in thickness, and the test specimen is compressed to 40% (12 mm) of the initial thickness.　The compressive strength can be measured, for example, using a universal testing machine (Tinius Olesen 10 ST) equipped with a 10 kN load cell.

[0208] It is preferable that there should be no yield point in the force-displacement curve obtained in the test for measuring the compressive strength in the 40% thickness direction of the polyurethane foam in accordance with European Standard EN 826:2013.　If there is no yield point in the force-displacement curve, the polyurethane foam that is compressed can deform elastically rather than plastically.　Thus, after the applied pressure is released, the polyurethane foam can recover its original shape before compression.

[0209] The presence of the yield point in the force-displacement curve can be determined as follows.　First, the compressive strength [kPa] in the thickness direction of the polyurethane foam is measured in accordance with the European standard EN 826:2013, except that the dimensions of the test specimen are 50 mm in width, 50 mm in length, and 30 mm in thickness, and the test specimen is compressed to a thickness of 40% (12 mm) of the initial thickness.　The force-displacement curve is then obtained.　In the force-displacement curve, the X-axis represents the displacement (compression amount), and the Y-axis represents the force (stress).

[0210] The presence of the yield point in the force-displacement curve is then determined.　When a load (compression) is applied to the polyurethane foam at a constant rate, the force (stress) increases along with an increase in the displacement (compression amount) in the force-displacement curve.　As shown in FIG. 1, the "yield point" refers to a peak P that first appears in the force-displacement curve when the force (stress) stops increasing and then suddenly decreases while the compression amount (displacement) keeps increasing.　When the peak P appears, it is determined that there is a yield point in the force-displacement curve.　When the peak P does not appear, it is determined that there is no yield point in the force-displacement curve.

[0211] The airflow resistivity of the polyurethane foam is preferably 16,000 Pa・s / m2or less, more preferably 14,000 Pa・s / m2or less, and more preferably 12,000 Pa・s / m2or less.　The airflow resistivity set to the above-mentioned upper limit value or less can allow the polyurethane foam to have high air permeability, and this configuration can prevent the temperature at a contact part between the user and the polyurethane foam from becoming too high.

[0212] The airflow resistivity of the polyurethane foam can be measured in accordance with the international standard ISO 9053-1:2018.　The airflow resistivity can be measured using, for example, a differential pressure gauge (product name "HM35" manufactured by Thommen, etc.), a mass gas flow meter (product name "C100L" manufactured by SmartTrak, etc.), or the like.

[0213] The tear strength of the polyurethane foam is preferably 100 N / m or more, more preferably 140 N / m or more, and more preferably 200 N / m or more.　The tear strength of the polyurethane foam is preferably 450 N / m or less, more preferably 425 N / m or less, and more preferably 400 N / m or less.　Setting the tear strength to the above-mentioned lower limit value or more can enhance the mechanical strength and handleability of the polyurethane foam.　Thus, damage to the polyurethane foam can be prevented when the polyurethane foam is packaged, transported, or used.　Further, this makes it possible to easily cut the polyurethane foam into a desired shape without damaging it.　Setting the tear strength to the above-mentioned upper limit value or less can allow the polyurethane foam to maintain high flexibility.

[0214] The tear strength of the polyurethane foam can be measured in accordance with ASTM D3574-01.

[0215] As a method for obtaining the polyurethane foam by foaming a foamable composition, a conventionally known method can be adopted.　Examples of such a method include a lamination method in which a foamable composition is supplied between two face materials and allowed to foam and an in-situ foaming method in which a foamable composition is injected into a cavity or a mold and allowed to freely foam.

[0216] The polyurethane foam has high flexibility and appropriate compression hardness, and after compressed, the polyurethane foam can recover its shape before compression without undergoing plastic deformation.　Thus, polyurethane foam is preferably used as a cushioning material.　Examples of the application of the polyurethane foam include: a vehicle interior material such as a seat cushion, a seat backrest, a headrest, or an armrest; a cushioning material for bedding or furniture such as a mattress or a sofa; and a cushioning material for clothing such as a shoe insole or a clothing pad.

[0217] The present invention will be described in more detail below using examples.　However, the present invention is not limited to these examples.　The specific numerical values of the compounding ratio (content ratio), physical property values, parameters, etc. used in the following description can be replaced with the corresponding upper limit values or lower limit values of the compounding ratio (content ratio), physical property values, parameters, etc. described in "Solution to Problem" and "Description of Embodiments".

[0218] (Synthetic examples 1 to 7 and Comparative synthetic examples 1 to 3) 　　　 Tall oil rosin as the rosin (a), a tall oil fatty acid as the biomass-derived fatty acid (b), the polymerized rosin (e1), and the polymerized fatty acid (e2) were fed into a reaction vessel in the mixing amounts shown in Table 1, and the mixture was stirred uniformly at 175°C under nitrogen atmosphere to obtain a solution.　Next, maleic anhydride (c1) was fed into the reaction vessel in the mixing amount shown in Table 1, and the mixture was heated at 200°C for 1 hour to perform a Diels-Alder reaction and an ene reaction.　Next, triethylene glycol (molecular weight of 150), polyethylene glycol (PEG200, number-average molecular weight of 200), and tripropylene glycol (molecular weight of 192) were fed into the reaction vessel as the polyol (p) in the mixing amounts shown in Table 1, and then adipic acid or sebacic acid was fed into the reaction vessel as the aliphatic saturated polycarboxylic acid (d) in the mixing amount shown in Table 1 to obtain a mixture.　After the mixture was heated to 245°C, 0.1 parts by mass of magnesium acetate was fed into the reaction vessel.　The mixture was then heated to 250°C to perform an esterification reaction until the acid value of the mixture became lower than 2.0 mgKOH / g.　A polyester polyol was then obtained.

[0219] The tall oil rosin included 40.2% by mass of abietic acid, 14.5% by mass of palustric acid, and 4.9% by mass of neoabietic acid as the resin acids (a1) having conjugated double bonds, and 0.4% by mass of pimaric acid and 23.2% by mass of dehydroabietic acid as the resin acids (a2).

[0220] The tall oil fatty acid included 44.8% by mass of oleic acid and 28.8% by mass of linoleic acid as the unsaturated fatty acids (b1), and 0.7% by mass of palmitic acid, 3.6% by mass of stearic acid, and 0.7% by mass of heptadecanoic acid as the saturated fatty acids (b2).

[0221] The polymerized rosin (e1) included 100% by mass of the rosin dimer.

[0222] The polymerized fatty acid (e2) included 81.2% by mass of the unsaturated fatty acid dimer.

[0223] The hydroxyl value, viscosity at 23°C, and number-average molecular weight of the polyester polyol were measured by the methods described above.　The results are shown in Table 1.

[0224] Note that the details of the polyether polyols used in the following Examples and Comparative examples are described below.

[0225] Polyether polyol (polyoxyalkylene polyol obtained by subjecting ethylene oxide and propylene oxide to ring-opening addition polymerization with glycerin, having no ester bond, a hydroxyl value of 48 mg KOH / g, a number-average molecular weight of 3571, a viscosity at 23°C of 0.7 Pa・s, product name "ARCOL Polyol 1108" manufactured by Covestro AG)

[0226] (Examples 1 to 8 and Comparative examples 1 to 5) 　　　 Polyol compositions were obtained by mixing the polyester polyols of Synthetic examples 1 to 7 and Comparative synthetic examples 1 to 3 and the polyether polyol in the mixing amounts shown in Table 2.

[0227] Into a reaction vessel, 0.20 parts by mass of an amine catalyst I (product name "NIAX catalyst A-33" manufactured by Momentive Performance Materials), 0.10 parts by mass of an amine catalyst II (product name "NIAX catalyst A-1_S" manufactured by Momentive Performance Materials), 0.11 parts by mass of an organometallic catalyst (tin salt of ethylhexanoic acid, product name "KOSMOS 29" manufactured by Evonik Industries AG), 3.43 parts by mass of water as a foaming agent, and 0.87 parts by mass of a surfactant (product name "NIAX L-895" manufactured by Momentive Performance Materials) as a foam stabilizer were fed and mixed uniformly to obtain an additive composition.

[0228] Next, 100 parts by mass of the polyol composition was fed into the reaction vessel and stirred at 250 rpm for 3 minutes.　After that, toluene diisocyanate (the number of isocyanate groups per molecule: 2.00, product name "LUPRANATE T80" manufactured by BASF) was fed into the reaction vessel as the polyisocyanate in the mixing amount shown in Table 2 and stirred at 2,000 rpm for 8 seconds.　In this manner, a foamable composition with an isocyanate index of 106 was obtained.　The foamable composition was then supplied in a plastic bag in a cardboard box, foamed, and then cured at 22°C for 24 hours.　In this manner, a polyurethane foam was obtained.

[0229] Note that, in Comparative examples 1 and 2, the polyester polyols of Comparative synthetic examples 1 and 2 were used.　The polyester polyols of Comparative synthetic examples 1 and 2 had too high viscosity.　Thus, the polyol compositions had low fluidity and low miscibility with the polyisocyanate.　Thus, it was difficult to foam the foamable compositions, and the polyurethane foams could not be obtained.

[0230] Furthermore, in Comparative example 5, the stability of the foamable composition was low.　Thus, the polyurethane foam collapsed after foaming, and the polyurethane foam could not be obtained.

[0231] The hydroxyl values of the polyol compositions were measured by the method described above.　The results are shown in Table 2.　　It is noted that “compressive strength in the 40% thickness direction” is simply expressed as “compressive strength”.

[0232] (Evaluation) 　　　 The open cell rate, density, airflow resistivity, and tear strength of the polyurethane foams were measured according to the procedures described above.　The measurement results were shown in Table 2.

[0233] Furthermore, the compressive strength in the 40% thickness direction of each of the polyurethane foams was measured according to the above-mentioned procedure.　The measurement results were shown in Table 2.

[0234] Further, the presence of the yield point in the force-displacement curve obtained in the test for measuring the compressive strength in the 40% thickness direction of the polyurethane foam in accordance with the European standard EN 826:2013 was determined according to the above-mentioned procedure.　In the "Yield point" column of Table 2, if it was determined that there was no yield point in the force-displacement curve, it was indicated as "no".　Further, in the "Yield point" column of Table 2, if it was determined that there was a yield point in the force-displacement curve, it was indicated as "yes".

[0235]

[0236]

[0237] It is possible to provide a polyol composition which, despite using a biomass-derived polyester polyol, has high miscibility with a polyisocyanate and is capable of producing a flexible polyurethane foam having high flexibility and appropriate compression hardness.

Claims

A polyol composition comprising a polyester polyol and a polyether polyol, the polyester polyol being a reaction product of raw material compounds including:　　　 a rosin (a) including a resin acid (a1) having a conjugated double bond;　　　 a biomass-derived fatty acid (b) including an unsaturated fatty acid (b1);　　　 an α,β-unsaturated carboxylic acid (c);　　　 an aliphatic saturated polycarboxylic acid (d); and　　　 a polyol (p) including a diol (p1) having an ether bond.　　　 The polyol composition according to claim 1, wherein the raw material compounds further include at least one of a polymerized rosin (e1) or a polymerized fatty acid (e2).　　　 The polyol composition according to claim 1, wherein the raw material compounds further include a polymerized rosin (e1).　　　 The polyol composition according to claim 1, wherein the raw material compounds further include a polymerized fatty acid (e2).　　　 The polyol composition according to claim 1, wherein a hydroxyl value of the polyester polyol is 200 mgKOH / g or less.　　　 The polyol composition according to claim 1, wherein a number-average molecular weight (Mn) of the polyester polyol is 800 or more.　　　 The polyol composition according to claim 1, wherein a viscosity of the polyester polyol at 23°C is 15.0 Pa・s or less.　　　 The polyol composition according to claim 1, wherein a hydroxyl value of the polyol composition is 150 mgKOH / g or less.　　　 A polyurethane foam that is a foam of a foamable composition containing the polyol composition according to claim 1, a polyisocyanate, and a foaming agent.　　　 The polyurethane foam according to claim 9, wherein the polyisocyanate includes an aromatic polyisocyanate.　　　 The polyurethane foam according to claim 9, wherein a number of isocyanate groups per molecule of the polyisocyanate is 2.10 or less.

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