Polyester polyol, polyurethane foam using same, and method for producing polyester polyol

Abstract

It is an object of the present invention to provide a biomass-derived polyester polyol which has high compatibility with various blowing agents and can be used to manufacture a polyurethane foam in which a reduction in compressive strength is reduced. The present invention relates to a polyester polyol for a polyurethane foam, in which the polyester polyol comprises a polyester polyol as a reaction product of a starting material compound containing: a rosin (a) containing a resin acid (a1) having a conjugated double bond; a biomass-derived fatty acid (b) containing an unsaturated fatty acid (b1); an alpha, beta-unsaturated carboxylic acid (c); and a polyol (d) containing a diol (d1) having an ether bond.

Description

Technical Field

[0001] This invention relates to biomass-derived polyester polyols, polyurethane foams manufactured using the same, and methods for manufacturing polyester polyols. Background Technology

[0002] Polyurethane foam is conventionally used as an insulation material in a variety of applications. Examples of such applications include building components (roofs, ceilings, and walls of buildings, etc.), household appliances (refrigerators, water heaters, etc.), vehicles (cars, airplanes, ships, etc.), pipes, and tanks.

[0003] Polyurethane foam is manufactured by reacting polyols with polyisocyanates in the presence of a blowing agent. Polyester polyols are used as such polyols. For example, polyester polyols are manufactured through the dehydration condensation of polyacids and polyols. Conventional polyester polyols are typically produced from feedstocks derived from fossil resources such as petroleum.

[0004] Reference List

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-038409 Summary of the Invention

[0007] Technical issues

[0008] In recent years, issues such as global warming and the depletion of fossil resources have received considerable attention. From this perspective, it is desirable to use biomass-derived polyester polyols in the manufacture of polyurethane foam.

[0009] However, research on the effects of biomass-derived polyester polyols on the physical properties of polyurethane foam is insufficient. The inventors have conducted research and found that biomass-derived polyester polyols can reduce the compressive strength of polyurethane foam.

[0010] In the manufacture of polyurethane foam, various blowing agents such as hydrocarbons and hydrofluoroolefins are used. However, conventional polyester polyols can have low compatibility with blowing agents. Polyester polyols with low compatibility with blowing agents are difficult to use in the manufacture of polyurethane foam. Therefore, polyester polyols are required to have high compatibility with various blowing agents.

[0011] The purpose of this invention is to provide a biomass-derived polyester polyol that has high compatibility with various foaming agents and can be used to manufacture polyurethane foam with reduced compressive strength.

[0012] Solution to the problem

[0013] Regarding the above-mentioned problems, the inventors have conducted various studies and found that the problems can be solved by the following polyester polyols.

[0014] This invention relates to a polyester polyol for use in polyurethane foam.

[0015] The polyester polyol includes a polyester polyol that is a reaction product of a raw material compound, the raw material compound containing:

[0016] Rosin (a) containing resin acid (a1) with conjugated double bonds;

[0017] Fatty acids (b) from biomass sources containing unsaturated fatty acids (b1);

[0018] α,β-unsaturated carboxylic acids (c); and

[0019] Polyols (d) containing diols (d1) with ether bonds.

[0020] Beneficial effects of the invention

[0021] The present invention provides a biomass-derived polyester polyol that has high compatibility with various foaming agents and can be used to manufacture polyurethane foam with reduced compressive strength (even when using biomass raw materials). Detailed Implementation

[0022] (Polyester polyol)

[0023] This invention relates to polyester polyols for use in polyurethane foams. The polyester polyols include polyester polyols that are reaction products of raw material compounds, the raw material compounds containing:

[0024] Rosin (a) containing resin acid (a1) with conjugated double bonds;

[0025] Fatty acids (b) from biomass sources containing unsaturated fatty acids (b1);

[0026] α,β-unsaturated carboxylic acids (c); and

[0027] Polyols (d) containing diols (d1) with ether bonds.

[0028] The polyester polyol used in polyurethane foam is preferably a polyester polyol that is a reaction product of a raw material compound, wherein the raw material compound contains:

[0029] Rosin (a') containing resin acids (a1) with conjugated double bonds;

[0030] Fatty acids (b) from biomass sources containing unsaturated fatty acids (b1);

[0031] α,β-unsaturated carboxylic acids (c); and

[0032] Polyols (d) containing diols (d1) with ether bonds.

[0033] For the polyester polyol of the present invention, rosin (a) containing a resin acid (a1) with conjugated double bonds and biomass-derived fatty acid (b) containing unsaturated fatty acid (b1) are used as biomass-derived raw materials. Each of the rosin (a) and the biomass-derived fatty acid (b) is added to an α,β-unsaturated carboxylic acid (c) via a Diels-Alder reaction or an olefin reaction to obtain a polyacid having multiple carboxyl groups. Furthermore, this carboxyl group is esterified with the hydroxyl group of the polyol (d) to obtain the polyester polyol.

[0034] As mentioned above, using rosin (a) modified with α,β-unsaturated carboxylic acid (c) can reduce the decrease in compressive strength of polyurethane foam. However, using rosin (a) modified with α,β-unsaturated carboxylic acid (c) alone can reduce the compatibility between polyester polyol and blowing agent. As a countermeasure, using biomass-derived fatty acids (b) modified with α,β-unsaturated carboxylic acid (c) can enhance the compatibility between polyester polyol and blowing agent.

[0035] Therefore, rosin (a) modified with α,β-unsaturated carboxylic acid (c) is used in combination with fatty acids (b) derived from biomass and modified with α,β-unsaturated carboxylic acid (c). This allows for the production of polyester polyols that exhibit high compatibility with various blowing agents and can be used to manufacture polyurethane foams with reduced compressive strength (even when using biomass raw materials).

[0036] In this invention, "biomass" refers to organic resources derived from organisms or plants, other than those derived from fossil resources. Examples of biomass include wood, seaweed, animal carcasses and excrement, and plankton.

[0037] "Bio-derived" means a substance made using at least a portion of organic resources derived from organisms or plants as raw materials, but does not include substances made using only resources derived from fossil resources.

[0038] Conversely, substances made solely from fossil-derived resources without using organic resources derived from organisms or plants are called "fossil-derived" substances. Examples of fossil-derived resources include coal, oil, and natural gas.

[0039] The polyester polyol of the present invention is a reaction product containing raw material compounds, each of which is described above as follows: rosin (a), a fatty acid from biomass (b), an α,β-unsaturated carboxylic acid (c), and a polyol (d). Hereinafter, the raw material compounds constituting the polyester polyol of the present invention will be described sequentially.

[0040] (Rosin(a))

[0041] Rosin (a) is derived from biomass and is used as one of the raw material compounds constituting polyester polyols. Rosin (a) is typically obtained by distilling vegetable oil resins and removing volatile components. Examples of vegetable oil resins include pine resin found in pine trees. Examples of volatile components include turpentine.

[0042] Rosin (a) contains a resin acid (a1) having conjugated double bonds. The resin acid (a1) having conjugated double bonds preferably has 12 or more carbon atoms, more preferably 15 or more, and even more preferably 18 or more. The resin acid (a1) having conjugated double bonds preferably has 35 or less carbon atoms, more preferably 30 or less, and even more preferably 25 or less. The resin acid (a1) having conjugated double bonds is preferably a monocarboxylic acid having one carboxyl group in its molecule.

[0043] The conjugated double bonds of the resin acid (a1) can be added to α,β-unsaturated carboxylic acids (c) via the Diels-Alder reaction. The conjugated double bonds of the resin acid (a1) are preferably at least one of s-cis type conjugated double bonds and conjugated double bonds that can be isomerized to form s-cis type conjugated double bonds. More preferably, they are s-cis type conjugated double bonds. Examples of conjugated double bonds that can be isomerized to form s-cis type conjugated double bonds include s-trans type conjugated double bonds. An s-cis type conjugated double bond is one in which the two double bonds are located on the same side (cis type) relative to the single bond that bonds the two double bonds together. An s-trans type conjugated double bond is one in which the two double bonds are located on different sides (trans type) relative to the single bond that bonds the two double bonds together. The conjugated double bonds of the resin acid (a1) preferably do not include the double bonds contained in the aromatic ring structure. Furthermore, the resin acid (a1) having conjugated double bonds preferably does not include aromatic polycarboxylic acids (e) and aromatic resin acids.

[0044] Examples of resin acids (a1) having conjugated double bonds include alicyclic resin acids such as abietic acid, neoabietic acid, longleaf abietic acid, and L-piperidine. L-piperidine is preferred. Because L-piperidine has an s-cis conformation, it exhibits high reactivity with α,β-unsaturated carboxylic acids (c). One type of resin acid (a1) having conjugated double bonds can be used alone, or two or more types can be used in combination.

[0045] Abietic acid, neoabietic acid, and longifolic acid can be readily isomerized to L-piperidine by heating in a reaction with α,β-unsaturated carboxylic acids (c). Therefore, L-piperidine, which is isomerized from abietic acid, neoabietic acid, and longifolic acid, can be used as L-piperidine. That is, L-piperidine can be an isomerized product of at least one of abietic acid, neoabietic acid, and longifolic acid. Preferably, L-piperidine is an isomerized product of at least one of abietic acid, neoabietic acid, and longifolic acid.

[0046] Abietic acid, neoabietic acid, and longleaf abietic acid are preferably isomerized to L-piperic acid by heating. The heating temperature is preferably 150 to 300°C, and more preferably 175 to 200°C.

[0047] The content of resin acid (a1) with conjugated double bonds in rosin (a) is preferably 25% by mass or more, more preferably 40% by mass or more, more preferably 50% by mass or more, and even more preferably 55% by mass or more. The content of resin acid (a1) with conjugated double bonds in rosin (a) is preferably 100% by mass or less, more preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0048] Rosin (a) preferably contains a resin acid (a2), which is at least one of an alicyclic resin acid and an aromatic resin acid without conjugated double bonds. The resin acid (a2) preferably has 12 or more carbon atoms, more preferably 15 or more, and even more preferably 18 or more. The resin acid (a2) preferably has 35 or less carbon atoms, more preferably 30 or less, and even more preferably 25 or less. The resin acid (a2) is preferably a monocarboxylic acid having one carboxyl group in its molecule.

[0049] Examples of resin acids (a2) include alicyclic resin acids without conjugated double bonds, such as pimaric acid, isopimaric acid, and sandaracopidrilic acid; and aromatic resin acids such as dehydrorosinic acid. Among these, pimaric acid, isopimaric acid, and dehydrorosinic acid are preferred, with pimaric acid and dehydrorosinic acid being more preferred. One type of resin acid (a2) may be used alone, or two or more types may be used in combination.

[0050] The content of resin acid (a2) in rosin (a) is preferably 1% by mass or more, and more preferably 15% by mass or more. The content of resin acid (a2) in rosin (a) is preferably 50% by mass or less, more preferably 40% by mass or less, and more preferably 35% by mass or less.

[0051] Examples of rosin (a) containing a resin acid (a1) with conjugated double bonds include biomass-derived rosin, such as gum rosin, tall oil rosin, and wood rosin. Tall oil rosin is preferred. The use of tall oil rosin can reduce the decrease in compressive strength of polyurethane foam. One type of biomass-derived rosin can be used alone, or two or more types can be used in combination.

[0052] The content of rosin (a) relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d) is preferably 5% by mass or more, more preferably 10% by mass or more, and particularly preferably 15% by mass or more. The content of rosin (a) relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d) is preferably 35% by mass or less, more preferably 25% by mass or less, and particularly preferably 23% by mass or less. A rosin (a) content equal to or greater than the lower limit can reduce the decrease in compressive strength of the polyurethane foam. A rosin (a) content equal to or less than the upper limit makes it possible to provide polyester polyols with improved compatibility with blowing agents.

[0053] (Fatty acids from biomass sources (b))

[0054] Biomass-derived fatty acids (b) are used as one of the raw material compounds for the formation of polyester polyols. Biomass-derived fatty acids (b) contain unsaturated fatty acids (b1). Unsaturated fatty acids (b1) are also derived from biomass.

[0055] Biomass-derived fatty acids (b) are aliphatic monocarboxylic acids having a carboxyl group at the end of a straight-chain or branched hydrocarbon chain. Examples of biomass-derived fatty acids (b) include aliphatic monocarboxylic acids represented by R-COOH, where R is a straight-chain or branched, saturated or unsaturated monovalent hydrocarbon group.

[0056] Examples of unsaturated fatty acids (b1) include those derived from R 1 -COOH (where R) 1 It is an aliphatic monocarboxylic acid represented by a straight-chain or branched unsaturated monovalent hydrocarbon group.

[0057] The unsaturated fatty acid (b1) preferably has 12 or more carbon atoms, more preferably 14 or more, and even more preferably 16 or more. The unsaturated fatty acid (b1) preferably has 30 or less carbon atoms, and even more preferably 25 or less.

[0058] Examples of unsaturated fatty acids (B1) include myristicin, palmitoleic acid, oleic acid, isoleic acid, eicosapentaenoic acid, linoleic acid, alpha-linolenic acid, gamma-linolenic acid, and arachidonic acid. Palmitoleic acid, oleic acid, and linoleic acid are preferred, and oleic acid and linoleic acid are more preferred. One type of unsaturated fatty acid (B1) may be used alone, or two or more types may be used in combination.

[0059] The content of unsaturated fatty acids (b1) in the fatty acids (b) from biomass sources is preferably 50% by mass or more, and more preferably 70% by mass or more. The content of unsaturated fatty acids (b1) in the fatty acids (b) from biomass sources 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.

[0060] Fatty acids (b) from biomass sources preferably contain saturated fatty acids (b2). Examples of saturated fatty acids (b2) include those derived from R... 2 -COOH (where R) 2 It is an aliphatic monocarboxylic acid represented by a straight-chain or branched saturated monovalent hydrocarbon group.

[0061] Examples of saturated fatty acids (B2) include caprylic acid, nonanoic acid, capric acid, lauric acid, myristic acid, palmitic acid, heptadecanic acid, stearic acid, arachidic acid, behenic acid, and tetracosanoic acid. Palmitic acid, heptadecanic acid, and stearic acid are preferred. One type of saturated fatty acid (B2) may be used alone, or two or more types may be used in combination.

[0062] The content of 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, and even more preferably 2% by mass or more. The content of 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 even more preferably 10% by mass or less.

[0063] Examples of biomass-derived fatty acids (b) include linseed oil fatty acids, tung oil fatty acids, castor oil fatty acids, soybean oil fatty acids, tall oil fatty acids, rice bran oil fatty acids, palm oil fatty acids, coconut oil fatty acids, dehydrated castor oil fatty acids, sunflower oil fatty acids, rapeseed oil fatty acids, canola oil fatty acids, and cottonseed oil fatty acids. Tall oil fatty acids are preferred. One type of biomass-derived fatty acid (b) may be used alone, or two or more types may be used in combination.

[0064] Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d), the content of biomass-derived fatty acids (b) is preferably 10% by mass or more, more preferably 15% by mass or more, more preferably 17% by mass or more, and particularly preferably 19% by mass or more. Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d), the content of biomass-derived fatty acids (b) is preferably 35% by mass or less, more preferably 30% by mass or less, more preferably 25% by mass or less, more preferably 24% by mass or less, and particularly preferably 22% by mass or less. A biomass-derived fatty acid (b) content equal to or greater than the lower limit allows for the provision of polyester polyols with improved compatibility with the blowing agent. A biomass-derived fatty acid (b) content equal to or less than the upper limit reduces the decrease in compressive strength of the polyurethane foam.

[0065] The mass ratio of rosin (a) to biomass-derived fatty acid (b) in the raw material compound [(a) / (b)] is more preferably 0.13 or greater, more preferably 0.50 or greater, more preferably 0.75 or greater, and particularly preferably 0.80 or greater. The mass ratio of rosin (a) to biomass-derived fatty acid (b) in the raw material compound [(a) / (b)] is preferably 2.00 or less, more preferably 1.50 or less, and particularly preferably 1.20 or less. A mass ratio [(a) / (b)] equal to or greater than the lower limit can reduce the decrease in the compressive strength of the polyurethane foam. A mass ratio [(a) / (b)] equal to or less than the upper limit makes it possible to provide a polyester polyol with improved compatibility with the blowing agent.

[0066] (α,β-unsaturated carboxylic acid (c))

[0067] α,β-Unsaturated carboxylic acid (c) is used as a raw material compound constituting polyester polyol. α,β-Unsaturated carboxylic acid (c) is added to the aforementioned rosin (a) and biomass-derived fatty acid (b) via a Diels-Alder reaction or an olefin reaction. Therefore, a carboxyl group can be introduced into each of the rosin (a) and biomass-derived fatty acid (b). As a result, rosin (a) and biomass-derived fatty acid (b) can be incorporated into the molecular structure of the polyester polyol. α,β-Unsaturated carboxylic acid (c) is preferably an α,β-unsaturated aliphatic carboxylic acid.

[0068] Examples of α,β-unsaturated carboxylic acids (c) include α,β-unsaturated dicarboxylic acids (c1) and α,β-unsaturated monocarboxylic acids (c2). α,β-unsaturated dicarboxylic acids (c1) are preferred. One type of α,β-unsaturated carboxylic acid (c) may be used alone, or two or more types may be used in combination.

[0069] The α,β-unsaturated carboxylic acid (c) preferably contains an α,β-unsaturated dicarboxylic acid (c1). The α,β-unsaturated dicarboxylic acid (c1) has unsaturated bonds. Therefore, the α,β-unsaturated dicarboxylic acid (c1) can function as a dienophile in the Diels-Alder reaction and as an enophile in alkene reactions. Examples of unsaturated bonds include carbon-carbon double bonds and carbon-carbon triple bonds. Carbon-carbon double bonds are preferred. The α,β-unsaturated dicarboxylic acid (c1) is preferably an α,β-unsaturated aliphatic dicarboxylic acid.

[0070] The number of carbon atoms in α,β-unsaturated dicarboxylic acids (C1) is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less. The number of carbon atoms in α,β-unsaturated dicarboxylic acids (C1) is preferably 3 or more, and even more preferably 4 or more.

[0071] Examples of α,β-unsaturated dicarboxylic acids (C1) include α,β-unsaturated dicarboxylic acids and their anhydrides, with α,β-unsaturated aliphatic dicarboxylic acids and their anhydrides being preferred. Specifically, examples include fumaric acid, itaconic acid, maleic acid, mesoconic acid, citraconic acid, and their anhydrides. Among these, maleic acid and maleic anhydride are preferred, and maleic anhydride is more preferred. Itaconic acid, mesoconic acid, citraconic acid, or their anhydrides formed by the thermal decomposition of citric acid can also be used as α,β-unsaturated dicarboxylic acids (C1). One type of α,β-unsaturated dicarboxylic acid (C1) can be used alone, or two or more types can be used in combination.

[0072] The content of α,β-unsaturated dicarboxylic acid (c1) in 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 even more preferably 99% by mass or more. The content of α,β-unsaturated dicarboxylic acid (c1) in α,β-unsaturated carboxylic acid (c) is preferably 100% by mass or less.

[0073] α,β-unsaturated carboxylic acids (c) may contain α,β-unsaturated monocarboxylic acids (c2). α,β-unsaturated monocarboxylic acids (c2) are preferably α,β-unsaturated aliphatic monocarboxylic acids.

[0074] The α,β-unsaturated monocarboxylic acid (C2) preferably has 10 or fewer carbon atoms, more preferably 8 or fewer, and even more preferably 5 or fewer. The α,β-unsaturated monocarboxylic acid (C2) preferably has 3 or more carbon atoms. Examples of α,β-unsaturated monocarboxylic acids (C2) include α,β-unsaturated monocarboxylic acids and their anhydrides, and preferably α,β-unsaturated aliphatic monocarboxylic acids and their anhydrides. Specific examples include acrylic acid, methacrylic acid, and crotonic acid. One type of α,β-unsaturated monocarboxylic acid (C2) can be used alone, or two or more types can be used in combination.

[0075] In the raw material compound, the mass ratio of α,β-unsaturated carboxylic acid (c) to rosin (a) [(c) / (a)] is preferably 0.15 or greater, more preferably 0.30 or greater, more preferably 0.45 or greater, and particularly preferably 0.47 or greater.

[0076] In the raw material compound, the mass ratio of α,β-unsaturated carboxylic acid (c) to rosin (a) [(c) / (a)] is preferably 2.00 or less, more preferably 1.50 or less, more preferably 0.90 or less, and even more preferably 0.55 or less, and particularly preferably 0.51 or less.

[0077] In the raw material compound, the mass ratio of the total amount of α,β-unsaturated carboxylic acid (c) to rosin (a) and biomass-derived fatty acid (b) [(c) / (a + b)] is preferably 0.05 or greater, more preferably 0.10 or greater, more preferably 0.19 or greater, and particularly preferably 0.21 or greater.

[0078] In the raw material compound, the mass ratio of the total amount of α,β-unsaturated carboxylic acid (c) to rosin (a) and biomass-derived fatty acid (b) [(c) / (a + b)] is preferably 0.45 or less, more preferably 0.30 or less, more preferably 0.26 or less, and particularly preferably 0.24 or less.

[0079] Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d), the content of α,β-unsaturated carboxylic acids (c) is preferably 5.0% by mass or greater, more preferably 7.5% by mass or greater, more preferably 7.7% by mass or greater, and particularly preferably 8.5% by mass or greater. Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d), the content of α,β-unsaturated carboxylic acids (c) is preferably 15.0% by mass or less, more preferably 12.0% by mass or less, more preferably 11.0% by mass or less, more preferably 10.5% by mass or less, more preferably 9.5% by mass or less, and particularly preferably 9.0% by mass or less. An α,β-unsaturated carboxylic acid (c) content equal to or greater than the lower limit above can introduce a sufficient amount of carboxyl groups into rosin (a) and biomass-derived fatty acids (b). An amount of α,β-unsaturated carboxylic acid (c) equal to or less than the above upper limit can reduce the decrease in compressive strength of polyurethane foam.

[0080] Polyol (d) is used as one of the raw material compounds constituting polyester polyol. Polyol (d) contains a diol (d1) with an ether bond. The use of a diol (d1) with an ether bond allows for the provision of polyester polyols with further improved compatibility with blowing agents.

[0081] Examples of diols (d1) having ether bonds include aliphatic diols. Specific examples include polyethylene glycols such as diethylene glycol, triethylene glycol, and tetraethylene glycol; and polypropylene glycols such as dipropylene glycol, tripropylene glycol, and tetrapropylene glycol. Polyethylene glycol is preferred. Furthermore, diethylene glycol, triethylene glycol, and tetraethylene glycol are preferred, and diethylene glycol is more preferred. One type of diol (d1) can be used alone, or two or more types can be used in combination.

[0082] In the raw material compound, the mass ratio of the total amount of diol (d1) with ether bonds to rosin (a) and fatty acid (b) from biomass source [(d1) / (a + b)] is preferably 0.30 or greater, more preferably 0.70 or greater, even more preferably 1.10 or greater, and particularly preferably 1.12 or greater. A mass ratio [(d1) / (a + b)] equal to or greater than the lower limit above makes it possible to provide a polyester polyol with improved compatibility with the blowing agent.

[0083] In the raw material compound, the mass ratio of the diol (d1) having ether bonds to the total amount of rosin (a) and biomass-derived fatty acids (b) [(d1) / (a ​​+ b)] is preferably 2.00 or less, more preferably 1.50 or less, and particularly preferably 1.35 or less. A mass ratio [(d1) / (a ​​+ b)] equal to or less than the above upper limit makes it possible to provide a polyester polyol with improved compatibility with the blowing agent.

[0084] The content of diols (d1) with ether bonds in the polyol (d) is preferably 20% by mass or more, more preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more. The content of diols (d1) with ether bonds in the polyol (d) is preferably 100% by mass or less, more preferably 99% by mass or less, and even more preferably 98% by mass or less.

[0085] The polyol (d) preferably contains a trivalent or higher polyol (d2). The use of a trivalent or higher polyol (d2) allows for a moderate improvement in the branching degree of the polyester polyol and enhances its reactivity with polyisocyanates. This further reduces the decrease in the compressive strength of the polyurethane foam.

[0086] Trivalent or higher polyols (d2) are preferably trivalent or higher aliphatic polyols. Examples include glycerol, trimethylolethane, trimethylolpropane, erythritol, diglycerol, pentaerythritol, sorbitol, anhydrosorbitol, and dipentaerythritol. Aliphatic polyols having 3 to 12 carbon atoms are preferred. Furthermore, glycerol, trimethylolethane, and trimethylolpropane are more preferred, with glycerol being even more preferred. One type of polyol (d2) can be used alone, or two or more types can be used in combination.

[0087] Trivalent or higher polyols (d2) can be derived from biomass. For example, glycerol derived from biomass can also be used. Examples of biomass-derived glycerol include glycerol obtained by hydrolyzing triglycerides contained in fats and oils.

[0088] In the raw material compound, the mass ratio of trivalent or higher polyol (d2) to the total amount of rosin (a) and biomass-derived fatty acid (b) [(d2) / (a + b)] is preferably 0.01 or greater, more preferably 0.02 or greater, and particularly preferably 0.03 or greater. A mass ratio [(d2) / (a + b)] equal to or greater than the lower limit mentioned above reduces the decrease in compressive strength of the polyurethane foam.

[0089] In the raw material compound, the mass ratio of trivalent or higher polyol (d2) to the total amount of rosin (a) and biomass-derived fatty acids (b) [(d2) / (a + b)] is preferably 0.35 or less, more preferably 0.20 or less, more preferably 0.08 or less, and particularly preferably 0.05 or less. A mass ratio [(d2) / (a + b)] equal to or less than the above upper limit allows for a reduction in the viscosity of the polyester polyol and improved compatibility with the foaming agent.

[0090] The content of trivalent or higher polyols (d2) in polyol (d) is preferably 0.3% by mass or more, more preferably 2.5% by mass or more, and even more preferably 2.7% by mass or more. The content of trivalent or higher polyols (d2) in polyol (d) is preferably 30.0% by mass or less, more preferably 10.0% by mass or less, even more preferably 6.0% by mass or less, and particularly preferably 4.0% by mass or less.

[0091] Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d), the content of polyol (d) is preferably 25.0% by mass or greater, more preferably 35.0% by mass or greater, and particularly preferably 45.0% by mass or greater, and particularly preferably 50.0% by mass or greater. Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d), the content of polyol (d) is preferably 70.0% by mass or less, more preferably 60.0% by mass or less, and particularly preferably 55.0% by mass or less. A polyol (d) content equal to or greater than the lower limit above can increase the crosslinking density of the polyurethane foam and reduce the decrease in compressive strength. A polyol (d) content equal to or less than the upper limit above can increase the crosslinking density of the polyurethane foam and reduce the decrease in compressive strength.

[0092] (Aromatic polycarboxylic acids (e))

[0093] The raw material compound preferably further comprises an aromatic polycarboxylic acid (e). That is, the polyester polyol of the present invention is preferably a polyester polyol as a reaction product of the raw material compound, said raw material compound containing:

[0094] Rosin (a) containing resin acid (a1) with conjugated double bonds;

[0095] Fatty acids (b) from biomass sources containing unsaturated fatty acids (b1);

[0096] α,β-unsaturated carboxylic acids (c);

[0097] Polyols (d) containing diols (d1) with ether bonds; and

[0098] Aromatic polycarboxylic acids (e).

[0099] The use of aromatic polycarboxylic acids (e) can improve the compressive strength of polyurethane foam.

[0100] Examples of aromatic polycarboxylic acids (e) include aromatic polycarboxylic acids and their anhydrides. Specific examples include phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, biphenyl dicarboxylic acid, trimellitic acid, pyromellitic acid, and their anhydrides. Among these, phthalic acid, isophthalic acid, terephthalic acid, and their anhydrides are preferred, and isophthalic acid and phthalic anhydride (the anhydride of phthalic acid) are more preferred. One type of aromatic polycarboxylic acid (e) may be used alone, or two or more types may be used in combination.

[0101] Terephthalic acid can be produced in the reaction mixture by hydrolyzing polyethylene terephthalate obtained from plastic products that are industrial waste.

[0102] From the viewpoint of compressive strength, in the raw material compound, the mass ratio of aromatic polycarboxylic acids (e) to the total amount of rosin (a) and biomass-derived fatty acids (b) [(e) / (a + b)] is preferably 0.05 or greater, more preferably 0.10 or greater, even more preferably 0.20 or greater, and particularly preferably 0.23 or greater. A mass ratio [(e) / (a + b)] equal to or greater than the lower limit mentioned above reduces the decrease in compressive strength of the polyurethane foam.

[0103] In the raw material compound, the mass ratio of aromatic polycarboxylic acids (e) to the total amount of rosin (a) and biomass-derived fatty acids (b) [(e) / (a + b)] is preferably 0.35 or less, more preferably 0.30 or less, even more preferably 0.27 or less, and particularly preferably 0.25 or less. A mass ratio [(e) / (a + b)] equal to or less than the above-mentioned upper limit allows for a reduction in the viscosity of the polyester polyol.

[0104] Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), polyols (d), and aromatic polycarboxylic acids (e), the content of aromatic polycarboxylic acids (e) is preferably 3.0% by mass or greater, more preferably 5.0% by mass or greater, more preferably 7.6% by mass or greater, more preferably 8.1% by mass or greater, and particularly preferably 8.6% by mass or greater. Relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), polyols (d), and aromatic polycarboxylic acids (e), the content of aromatic polycarboxylic acids (e) is preferably 15.0% by mass or less, more preferably 10.0% by mass or less, and particularly preferably 9.5% by mass or less. A content of aromatic polycarboxylic acids (e) equal to or greater than the lower limit above allows for a reduction in the compressive strength of the polyurethane foam. A content of aromatic polycarboxylic acids (e) equal to or less than the upper limit above allows for the provision of polyester polyols with improved compatibility with the blowing agent.

[0105] As described above, the polyester polyol of the present invention is a reaction product of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyol (d). Rosin (a) and fatty acids (b) are each derived from biomass and react with α,β-unsaturated carboxylic acids (c) to incorporate these components into the molecular structure of the polyester polyol.

[0106] Specifically, rosin (a) contains a resin acid (a1) with a conjugated double bond. Biomass-derived fatty acids (b) contain unsaturated fatty acids (b1). Therefore, when these components react with α,β-unsaturated carboxylic acids (c), the α,β-unsaturated carboxylic acids (c) add to the resin acid (a1) via a Diels-Alder reaction, forming an adduct. Alternatively, α,β-unsaturated carboxylic acids (c) add to the unsaturated fatty acid (b1) via a Diels-Alder reaction or an olefin reaction, forming an adduct.

[0107] The polyester polyols of the present invention include units derived from the above-described adducts. Examples of units derived from the above-described adducts include unit (I) derived from an adduct obtained by adding α,β-unsaturated carboxylic acid (c) to a resin acid (a1), and unit (II) derived from an adduct obtained by adding α,β-unsaturated carboxylic acid (c) to an unsaturated fatty acid (b1).

[0108] As unit (I), it is preferably derived from an adduct obtained by adding maleic acid or maleic anhydride to L-piperic acid via a Diels-Alder reaction. L-piperic acid may be an isomerization product of at least one of abietic acid, neoabietic acid, and longleaf abietic acid. Unit (II) is preferably derived from an adduct obtained by adding maleic acid or maleic anhydride to oleic acid via an olefin reaction, or from at least one of an adduct obtained by adding maleic acid or maleic anhydride to linoleic acid via a Diels-Alder reaction, and more preferably from two of the above units.

[0109] As described above, the Diels-Alder reaction or olefin reaction using α,β-unsaturated carboxylic acids (c) allows rosin (a) and biomass-derived fatty acids (b) to be incorporated into the molecular structure of polyester polyols.

[0110] In addition, multiple carboxyl groups derived from rosin (a), a raw material compound, fatty acids (b), and α,β-unsaturated carboxylic acids (c) undergo a condensation reaction with the hydroxyl groups of a polyol (d) to form ester bonds, thereby obtaining a polyester polyol.

[0111] (Method for manufacturing polyester polyols)

[0112] The method for manufacturing the polyester polyol of the present invention includes the step of reacting a raw material compound comprising rosin (a) containing a resin acid (a1) having a conjugated double bond, a biomass-derived fatty acid (b) containing an unsaturated fatty acid (b1), an α,β-unsaturated carboxylic acid (c), and a polyol (d) containing a diol (d1) having an ether bond to obtain the polyester polyol.

[0113] The reaction of the raw material compounds is preferably carried out by heating the raw material compounds. The heating temperature is preferably 150 to 300°C. Heating promotes the Diels-Alder reaction, olefin reaction and esterification reaction as described above to obtain polyester polyols. The reaction of the raw material compounds can be carried out while blowing an inert gas (e.g., nitrogen) into the reaction system.

[0114] The reaction of the starting material compounds can be carried out in the presence of catalysts used to promote Diels-Alder reactions and olefin reactions, or catalysts used to promote esterification reactions. Diels-Alder reactions or olefin reactions can be readily promoted by heating the starting material compounds. Therefore, catalysts promoting Diels-Alder reactions or olefin reactions may not be used. Examples of catalysts used to promote esterification reactions include lithium acetate and magnesium acetate. Each of these catalysts may be used alone, or two or more types may be used in combination.

[0115] There are no particular restrictions on the order in which rosin (a), biomass-derived fatty acids (b), and α,β-unsaturated carboxylic acids (c) are reacted. For example, the following synthetic methods (I) to (III) can be used.

[0116] (Synthetic Method (I))

[0117] First, each of rosin (a) and a fatty acid (b) of biomass origin, and an α,β-unsaturated carboxylic acid (c) undergoes a Diels-Alder reaction or an olefin reaction to obtain an adduct. Next, this adduct is subjected to an esterification reaction with a polyol (d) and, if desired, an aromatic polycarboxylic acid (e) to obtain a polyester polyol.

[0118] (Synthetic Method (II))

[0119] First, α,β-unsaturated carboxylic acid (c), an aromatic polycarboxylic acid (e), and a polyol (d) are subjected to an esterification reaction to obtain an esterified product. Next, the esterified product, rosin (a), and a biomass-derived fatty acid (b) are subjected to a Diels-Alder reaction or an olefin reaction to obtain a polyester polyol.

[0120] (Synthetic Method (III))

[0121] Rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyols (d) are mixed and simultaneously subjected to a Diels-Alder reaction or olefin reaction and an esterification reaction. Then, aromatic polycarboxylic acids (e) are mixed as needed, leading to an esterification reaction. Thus, a polyester polyol is obtained.

[0122] Synthesis method (I) is preferred. The polyester polyol obtained by synthesis method (I) has a moderately branched molecular structure and high reactivity with polyisocyanates. This reduces the decrease in compressive strength of the polyurethane foam. From this point of view, it is preferred that the polyol (d) further contains a trivalent or higher polyol (d2).

[0123] The method for producing polyester polyols by synthetic method (I) includes the step (I-1): subjecting rosin (a) containing a resin acid (a1) with conjugated double bonds and a biomass-derived fatty acid (b) containing an unsaturated carboxylic acid (b1) to a Diels-Alder reaction or an olefin reaction with α,β-unsaturated carboxylic acid (c).

[0124] In step (I-1), an adduct of resin acid (a1) and α,β-unsaturated carboxylic acid (c) and an adduct of unsaturated fatty acid (b1) and α,β-unsaturated carboxylic acid (c) are obtained by Diels-Alder reaction or olefin reaction.

[0125] In step (I-1), the Diels-Alder reaction or alkene reaction is preferably carried out by heating rosin (a) containing a resin acid (a1) with conjugated double bonds, a biomass-derived fatty acid (b) containing unsaturated fatty acids (b1), and α,β-unsaturated carboxylic acids (c). The heating temperature is preferably 175 to 200°C.

[0126] The method for producing polyester polyol by synthetic method (I) further includes the step (I-2): subjecting an adduct of resin acid (a1) with α,β-unsaturated carboxylic acid (c), an adduct of unsaturated fatty acid (b1) with α,β-unsaturated carboxylic acid (c), a polyol (d) containing a diol (d1) having an ether bond, and an aromatic polycarboxylic acid (e) as needed to an esterification reaction to obtain polyester polyol.

[0127] In step (I-2), the esterification reaction is preferably carried out by heating the adduct, the polyol (d), and the desired aromatic polycarboxylic acid (e). The heating temperature is preferably 245 to 255°C.

[0128] In this invention, α,β-unsaturated carboxylic acids (c) are used in a Diels-Alder reaction or an olefin reaction to introduce rosin (a) and biomass-derived fatty acids (b) into the molecular structure of the polyester polyol. Both rosin (a) and fatty acids (b) are derived from biomass. Therefore, the polyester polyol of this invention achieves high biomass utilization.

[0129] The hydroxyl value of the polyester polyol is preferably 215 mg KOH / g or greater, more preferably 223 mg KOH / g or greater, and particularly preferably 225 mg KOH / g or greater.

[0130] The hydroxyl value of the polyester polyol is preferably 500 mg KOH / g or less, more preferably 350 mg KOH / g or less, and particularly preferably 265 mg KOH / g or less.

[0131] The hydroxyl value of polyester polyols can be measured according to ASTM D4274-16C.

[0132] When using multiple types of polyester polyols, the hydroxyl value of the polyester polyol is obtained by weighted averaging of the hydroxyl values ​​of the individual polyester polyols. Specifically, the weighted average hydroxyl value is determined by the following expression.

[0133] Weighted average hydroxyl value (mgKOH / g) = [H1×W1+ H2×W2+・・・+ H n ×W n ] / 100

[0134] In this expression, n is the number of types of polyester polyols, Hn It is the hydroxyl value (mgKOH / g) of the nth polyester polyol, and W n It is the mass percentage (mass%) of the nth polyester polyol.

[0135] The viscosity of the polyester polyol at 23°C is preferably 100 Pa·s or less, more preferably 50 Pa·s or less, and particularly preferably 10 Pa·s or less. Typically, polyester polyols obtained using biomass-derived raw materials can have high viscosity and may be difficult to use in the manufacture of polyurethane foams. However, in this invention, using rosin (a) and fatty acids (b) as biomass-derived raw materials reduces the viscosity of the polyester polyol. Polyester polyols with a viscosity equal to or less than the upper limit have high fluidity. Such polyester polyols can be uniformly mixed with polyisocyanates and blowing agents.

[0136] The viscosity of the polyester polyol at 23°C is preferably 2.5 Pa·s or greater, more preferably 3.0 Pa·s or greater, and particularly preferably 4.5 Pa·s or greater. A viscosity equal to or greater than the lower limit makes it possible to provide a polyester polyol with sufficient flowability to mix uniformly with the polyisocyanate and the foaming agent.

[0137] The viscosity of the polyester polyol at 23°C was measured using the following measuring device under the following measuring conditions.

[0138] • Measuring device: Rotational rheometer (e.g., the MCR 92 rheometer manufactured by Anton Paar GmbH)

[0139] • Geometry: A cone plate with a radius of 25 mm

[0140] • Shearing speed: 25 (s) -1 )

[0141] The number average molecular weight (Mn) of the polyester polyol is preferably 500 or greater, more preferably 600 or greater, and particularly preferably 725 or greater.

[0142] The number-average molecular weight (Mn) of the polyester polyol is preferably 900 or less, more preferably 780 or less, and particularly preferably 775 or less. Polyester polyols with a number-average molecular weight (Mn) equal to or less than the upper limit have reduced viscosity.

[0143] The number-average molecular weight (Mn) of the polyester polyol was calculated using size exclusion chromatography (SEC) converted to polystyrene. The SEC measurement conditions are as follows.

[0144] Eluent: Tetrahydrofuran solution containing 0.02% (v / v) acetic acid

[0145] Flow rate of elution buffer: 1 mL / min

[0146] Column (stationary phase): Agilent PLGel Mixed B-pillar × 3

[0147] Standard substance: Polystyrene (molecular weight: 580 to 6,500,000 g / mol)

[0148] Column temperature: 30°C

[0149] (Polyurethane foam)

[0150] Polyurethane foam is a foam containing a foaming composition of polyol (P), polyisocyanate (I), and a blowing agent. The polyol (P) used as a raw material for polyurethane foam can be a biomass-derived polyester polyol according to the present invention.

[0151] Polyurethane foam contains a urethane resin having urethane bonds formed by the reaction of a polyol (P) and a polyisocyanate (I). Preferably, the urethane resin further has an isocyanurate ring structure formed by the trimerization reaction of the isocyanate groups of the polyisocyanate (I). Polyurethane foam containing a urethane resin having an isocyanurate ring structure is commonly referred to as "polyisocyanurate foam". Due to the isocyanurate ring structure, polyisocyanurate foam exhibits high flame retardancy.

[0152] (Polyols (P))

[0153] The foaming composition contains a polyol (P). The polyol (P) includes the biomass-derived polyester polyol of the present invention. In this document, the biomass-derived polyester polyol of the present invention may be simply referred to as "polyester polyol (P1)".

[0154] As mentioned above, biomass-derived polyester polyols (P1) exhibit high compatibility with various blowing agents and can be used to manufacture polyurethane foams with reduced compressive strength. Therefore, biomass-derived polyester polyols (P1) are suitable for use as polyols (P).

[0155] As the polyol (P), only a biomass-derived polyester polyol (P1) may be used. Alternatively, the polyol (P) may contain a polyester polyol (P1) and other polyols (P2), such as those derived from fossil resources. Due to the combined use of rosin (a) and fatty acid (b), the polyester polyol (P1) of the present invention exhibits high compatibility not only with blowing agents but also with other polyols (P2). Therefore, polyurethane foam can be readily manufactured even when using other polyols (P2).

[0156] The content of polyester polyol (P1) in the polyol (P) is preferably 5% by mass or more, more preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more. In this case, polyurethane foam with high utilization of biomass raw materials can be manufactured.

[0157] The content of polyester polyol (P1) in the polyol (P) is preferably 100% by mass or less, more preferably 85% by mass or less, more preferably 75% by mass or less, and even more preferably 50% by mass or less. Even when other polyols (P2) are used, polyurethane foams with high utilization rates of biomass raw materials can be manufactured.

[0158] When other polyols (P2) are used, the content of other polyols (P2) in the polyol (P) is preferably 1% by mass or more, more preferably 10% by mass or more, more preferably 15% by mass or more, more preferably 20% by mass or more, more preferably 25% by mass or more, and particularly preferably 50% by mass or more. The content of other polyols (P2) in the polyol (P) is preferably 95% by mass or less, more preferably 90% by mass or less, and particularly preferably 80% by mass or less.

[0159] Other polyols (P2) may be polyols commonly used in the manufacture of polyurethane foams. Examples of other polyols (P2) include polylactone polyols, polycarbonate polyols, polyester polyols, polymer polyols, and polyether polyols. Examples of polyester polyols include aromatic polyester polyols. One type of other polyol (P2) may be used alone, or two or more of them may be used in combination.

[0160] Other polyols (P2) may be polyols derived from biomass or polyols derived from fossil resources, and are preferably polyols derived from fossil resources.

[0161] The other polyol (P2) preferably contains a polyether polyol. Using polyester polyol (P1) and polyether polyol as the other polyol (P2) can improve the compressive strength of polyurethane foam.

[0162] When the polyol (P) contains polyester polyol (P1) and polyether polyol as other polyol (P2), the polyol (d) contained in the raw material compound of polyester polyol (P1) preferably further contains trivalent or higher polyol (d2).

[0163] When the polyol (P) contains polyester polyol (P1) and polyether polyol as another polyol (P2), the content of trivalent or higher polyol (d2) is preferably 7% by mass or more, more preferably 10% by mass or more, relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyol (d) in the raw material compound of polyester polyol (P1). A content of trivalent or higher polyol (d2) equal to or greater than the lower limit mentioned above can improve the compressive strength of polyurethane foam.

[0164] When the polyol (P) contains a polyester polyol (P1) and a polyether polyol as another polyol (P2), the content of trivalent or higher polyol (d2) is preferably 20% by mass or less, more preferably 15% by mass or less, relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyol (d) in the raw material compound of the polyester polyol (P1). A content of trivalent or higher polyol (d2) equal to or less than the above-mentioned upper limit can reduce the viscosity of the polyester polyol (P1).

[0165] The other polyol (P2) preferably contains an aromatic polyester polyol. Using polyester polyol (P1) and aromatic polyester polyol as the other polyol (P2) can improve the thermal insulation of polyurethane foam.

[0166] When the polyol (P) contains polyester polyol (P1) and aromatic polyester polyol as other polyol (P2), the polyol (d) contained in the raw material compound of polyester polyol (P1) preferably further contains trivalent or higher polyol (d2).

[0167] When the polyol (P) contains polyester polyol (P1) and aromatic polyester polyol as other polyols (P2), the content of trivalent or higher polyol (d2) is preferably less than 7% by mass, more preferably 4% by mass or less, relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyol (d) in the raw material compound of polyester polyol (P1). A content of trivalent or higher polyol (d2) less than the above-mentioned upper limit can reduce the viscosity of polyester polyol (P1).

[0168] When the polyol (P) contains polyester polyol (P1) and aromatic polyester polyol as other polyols (P2), the content of trivalent or higher polyol (d2) is preferably 0.01% by mass or more, more preferably 0.02% by mass or more, relative to the total mass of rosin (a), biomass-derived fatty acids (b), α,β-unsaturated carboxylic acids (c), and polyol (d) in the raw material compound of polyester polyol (P1). A content of trivalent or higher polyol (d2) equal to or greater than the lower limit mentioned above can increase the hydroxyl value of polyester polyol (P1).

[0169] The hydroxyl value of the polyol (P) is preferably 150 to 500 mg KOH / g, more preferably 200 to 350 mg KOH / g, and even more preferably 220 to 280 mg KOH / g.

[0170] The same method used to measure the hydroxyl value of polyols (P) is employed as the method for measuring the hydroxyl value of polyester polyols.

[0171] (Polyisocyanate (I))

[0172] The foaming composition contains polyisocyanate (I). Polyisocyanate (I) has two or more isocyanate groups (-NCO) in its molecule.

[0173] Examples of polyisocyanates (I) include aliphatic polyisocyanates, alicyclic polyisocyanates, and aromatic polyisocyanates. Aromatic polyisocyanates are preferred. One type of polyisocyanate (I) may be used alone, or two or more types may be used in combination.

[0174] Examples of aromatic polyisocyanates include toluene diisocyanate, diphenylmethane diisocyanate (MDI), and polymethylene polyphenylene polyisocyanate (PMDI). Among these, polymethylene polyphenylene polyisocyanate (PMDI) is preferred.

[0175] (Foaming agent)

[0176] The foaming composition contains a foaming agent. Examples of foaming agents include water and low-boiling-point foaming agents such as hydrocarbons, hydrofluoroolefins, hydrochlorofluorocarbons, hydrofluorocarbons, hydrochlorocarbons, and chlorofluorocarbons. The boiling point of the low-boiling-point foaming agent is preferably 100°C or lower, and more preferably 50°C or lower. "Boiling point" refers to the boiling point under standard conditions (1 atm (101.325 kPa), 25°C). Foaming agents can be used alone, or two or more types can be used in combination.

[0177] Hydrocarbons and hydrofluoroolefins are preferred as blowing agents. These blowing agents are less likely to cause environmental problems such as global warming and ozone depletion, but may have low compatibility with biomass-derived polyols. However, the biomass-derived polyester polyol (P1) of the present invention has high compatibility with blowing agents as described above. Therefore, hydrocarbons and hydrofluoroolefins are preferred, and hydrocarbons are more preferred because they can exert the effects of the present invention.

[0178] Examples of hydrocarbons include propane, butane, pentane, hexane, heptane, cyclopropane, cyclobutane, cyclopentane, cyclohexane, and cycloheptane. Pentane and cyclopentane are preferred, and n-pentane, isopentane, and cyclopentane are more preferred. Hydrocarbons can be used alone, or two or more types can be used in combination. The hydrocarbon content in the blowing agent is preferably 10 to 100% by mass, more preferably 50 to 99% by mass, and even more preferably 93 to 97% by mass.

[0179] Examples of hydrofluoroolefins 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). Hydrofluoroolefins can be used alone or in combination of two or more types. The content of hydrofluoroolefins in the blowing agent is preferably 10 to 100% by mass, more preferably 50 to 99% by mass, and even more preferably 93 to 97% by mass.

[0180] The foaming agent preferably contains water. Water is also less likely to cause environmental problems such as global warming and ozone depletion. The water content in the foaming agent is preferably 0.1 to 15% by mass, more preferably 0.5 to 10% by mass, more preferably 1.5 to 7.5% by mass, and even more preferably 1.5 to 7% by mass.

[0181] The content of a blowing agent in the foaming composition relative to 100 parts by weight of polyol (P) is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, more preferably 5 parts by weight or more, more preferably 10 parts by weight or more, and even more preferably 14 parts by weight or more. The content of a blowing agent in the foaming composition relative to 100 parts by weight of polyol (P) is preferably 50 parts by weight or less, more preferably 30 parts by weight or less, and even more preferably 25 parts by weight or less.

[0182] (Catalysts used to form carbamates)

[0183] Preferably, the foaming composition contains a catalyst for forming urethane esters, which promotes the reaction for generating urethane ester bonds.

[0184] Examples of catalysts for the formation of carbamates include amine-based catalysts, ammonium-based catalysts, organopotassium-based catalysts, and organometallic catalysts. Amine-based catalysts are preferred. Catalysts for the formation of carbamates can be used alone, or two or more types can be used in combination.

[0185] The content of the catalyst for forming the urethane in the foaming composition is preferably 0.05 parts by mass or more, more preferably 0.25 parts by mass or more, and even more preferably 0.5 parts by mass or more, relative to 100 parts by mass of the polyol (P). The content of the catalyst for forming the urethane in the foaming composition is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less, relative to 100 parts by mass of the polyol (P).

[0186] (Trimerization catalyst)

[0187] Preferably, the foaming composition contains a trimerizing catalyst to promote the formation of isocyanurate rings. Isocyanate rings are formed through the trimerization reaction of isocyanate groups.

[0188] Examples of trimerizing catalysts include carboxylates, such as alkali metal salts and quaternary ammonium salts of carboxylic acids. Alkali metal salts of carboxylic acids are preferred. Examples of alkali metal salts of carboxylic acids include potassium acetate and potassium 2-ethylhexanoate. Trimerizing catalysts can be used alone or in combination of two or more of them.

[0189] (Flame retardant)

[0190] Preferably, the foaming composition contains a flame retardant. Examples of flame retardants include halogenated flame retardants such as tricresyl phosphate, tris(2-chloro-1-methylethyl) phosphate, tris(2-chloroethyl) phosphate, tris(2-chloroisopropyl) phosphate, tris(1,3-dichloropropyl) phosphate, and tris(2,3-dibromopropyl) phosphate, as well as halogen-free flame retardants such as triethyl phosphate. Flame retardants can be used alone, or two or more types can be used in combination.

[0191] (Foam stabilizer)

[0192] Preferably, the foaming composition contains a foam stabilizer. By using a foam stabilizer, polyurethane foam with a high closed-cell content can be manufactured.

[0193] Examples of foam stabilizers include silicone-based surfactants, such as organopolysiloxanes, organopolysiloxane-polyoxyalkylene copolymers, polyolefinic siloxanes having polyoxyalkylene side chains, and silicone-oil copolymers. Foam stabilizers can be used alone or in combination of two or more types. The content of the foam stabilizer in the foaming composition is preferably 0.5 to 10 parts by weight, and more preferably 1.0 to 5 parts by weight, relative to 100 parts by weight of the polyol (P).

[0194] The foaming composition may contain additional additives. Examples of additives include antioxidants, heat stabilizers, metal-induced degradation inhibitors, charge inhibitors, stabilizers, lubricants, softeners, pigments, and dyes.

[0195] The foaming composition comprises a polyol (P) containing a polyester polyol (P1), a polyisocyanate (I), and a foaming agent. The foaming composition is obtained by mixing the polyol (P) with the polyisocyanate (I) and the foaming agent.

[0196] During the manufacture of the foaming composition, a polyol (P) may be premixed with a solvent to obtain a polyol composition. This polyol composition may then be mixed with a polyisocyanate (I) and a foaming agent to obtain the foaming composition.

[0197] Examples of solvents for polyol compositions include benzene, toluene, xylene, mesitylene, chlorobenzene, o-dichlorobenzene, dichloromethane, 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-imidazolinone, dimethyl sulfoxide, and sulfolane. Solvents may be used alone or in combination of two or more types.

[0198] The polyol composition may contain components that can be included in the foaming composition. Examples of such components include: catalysts, such as catalysts for the formation of urethanes and trimerizing catalysts; and additives, such as flame retardants, foam stabilizers, antioxidants, heat stabilizers, metal-induced degradation inhibitors, charge inhibitors, stabilizers, lubricants, softeners, pigments, and dyes. One type of catalyst may be used alone, or two or more types may be used in combination. One type of additive may be used alone, or two or more types may be used in combination.

[0199] The isocyanate index of the foaming composition is preferably 90 or greater, and more preferably 110 or greater. An isocyanate index equal to or greater than the lower limit allows for the formation of a polyurethane foam that is three-dimensionally stable and hardly collapses.

[0200] Specifically, the isocyanate index of the foaming composition is preferably 250 or greater, and more preferably 275 or greater. An isocyanate index equal to or greater than the lower limit allows excess polyisocyanate (I) exceeding the polyol (P) to undergo trimerization to produce isocyanurate rings. Thus, polyurethane foams containing polyurethane resins having isocyanurate rings can be manufactured.

[0201] The isocyanate index of the foaming composition is preferably 450 or less, and more preferably 400 or less. An isocyanate index equal to or less than the upper limit makes it possible to provide polyurethane foam with excellent mechanical strength, thermal insulation and sound insulation properties.

[0202] When the polyol (P) contains a polyester polyol (P1) and a polyether polyol as another polyol (P2), the isocyanate index of the foaming composition is preferably 90 to 250, and more preferably 110 to 160. An isocyanate index of 90 or higher can help form a polyurethane foam that is difficult to collapse. An isocyanate index of 250 or lower can form a polyurethane foam with good mechanical and thermal insulation properties.

[0203] When the polyol (P) contains a polyester polyol (P1) and an aromatic polyester polyol as another polyol (P2), the isocyanate index of the foaming composition is preferably greater than 250, and preferably 450 or less. An isocyanate index greater than 250 allows for the formation of isocyanurate units. An isocyanate index of 450 or less allows for the formation of polyurethane foams with good mechanical and thermal insulation properties.

[0204] The isocyanate index of the foaming composition can be calculated using the following expression.

[0205] Isocyanate index = 100 × (equivalent number of isocyanate groups in polyisocyanate (I)) / (equivalent number of active hydrogen groups in polyol (P) + equivalent number of active hydrogen groups in water)

[0206] The equivalent number of isocyanate groups in polyisocyanate (I) can be calculated using the following expression.

[0207] The equivalent number of isocyanate groups in polyisocyanate (I) = 100 × the content of isocyanate groups in polyisocyanate (I) (mass%) × the amount of mixed polyisocyanate (I) (g) / the molecular weight of isocyanate groups (42g / mol)

[0208] The equivalent number of active hydrogen groups in a polyol (P) can be calculated using the following expression.

[0209] The equivalent number of active hydrogen groups in a polyol (P) = (W1 × H1 / 56100) + (W2 × H2 / 56100) + ... + (Wm × H m / 56100)

[0210] In this expression, W m It is the content (g) of the m-th polyol in the entire polyol (P), H m It is the hydroxyl value (mgKOH / g) of the m-th polyol, and m is an integer representing the number of types of polyol (P).

[0211] The hydroxyl value of the m-th polyol can be measured according to ASTM D4274-16C.

[0212] The equivalent number of active hydrogen groups in water can be calculated using the following expression. When the foaming composition contains water as a blowing agent, the equivalent number of active hydrogen groups in water needs to be considered when calculating the isocyanate index of the foaming composition.

[0213] The equivalent number of active hydrogen groups in water = (amount of water mixed in g) × 2 / 18

[0214] The compressive strength of the polyurethane foam in the thickness direction is more preferably 160 kPa or greater, more preferably 180 kPa or greater, and even more preferably 200 kPa or greater. Although biomass-derived raw materials are used, the aforementioned polyester polyol (P1) can reduce the decrease in the compressive strength of the polyurethane foam. Therefore, polyurethane foam with a high compressive strength of 160 kPa or higher can be manufactured. Therefore, the polyurethane foam is preferably a rigid polyurethane foam, more preferably a rigid polyisocyanurate foam.

[0215] The compressive strength of the polyurethane foam in the thickness direction is preferably 375 kPa or less, more preferably 350 kPa or less, and even more preferably 300 kPa or less.

[0216] The compressive strength of polyurethane foam in the thickness direction can be measured according to European standard EN826:2013, except that the test specimen has the following dimensions: 40 mm wide, 40 mm long, and 40 mm thick. For example, a universal testing machine (Tinius Olesen 10 ST) equipped with a 10 kN load cell can be used to measure the compressive strength.

[0217] The expansion ratio of the polyurethane foam is preferably 29 to 36 times, and more preferably 31 to 34 times. An expansion ratio of 29 times or greater reduces the weight of polyurethane foam per covered area. An expansion ratio of 36 times or less increases the compressive strength of the polyurethane foam.

[0218] The expansion ratio of polyurethane foam was measured using the following method. First, the polyurethane foam was cut to obtain a cubic specimen with a side length of 40 mm. The thickness of the specimen was measured according to ISO 1923 (1981) "Cellular plastics and rubbers - Determination of linear dimensions". The thickness of the specimen was measured at five freely chosen locations, and their arithmetic mean was calculated. The resulting value was defined as the specimen thickness. The apparent volume of the specimen [V (cm²)] was calculated using the specimen thickness. 3 Additionally, measure the weight of the sample [W(g)]. Calculate the expansion ratio of the polyurethane foam using the following formula.

[0219] The expansion ratio of polyurethane foam [times] = V / W

[0220] The closed-cell ratio of the polyurethane foam is preferably 75% or greater, more preferably 80% or greater, and even more preferably 85% or greater. The closed-cell ratio of the polyurethane foam is preferably 100% or less. A closed-cell ratio of 75% or greater improves thermal insulation and increases the compressive strength of the polyurethane foam.

[0221] The closed-cell ratio of polyurethane foam is measured according to standard ASTM D6226-15.

[0222] As a method for foaming a foaming composition to obtain polyurethane foam, conventionally known methods can be used. Examples of such methods include: a lamination method in which a foaming composition is supplied between two planar members and foamed; a spraying method in which a foaming composition is sprayed onto an adherend using a sprayer and foamed; and a foam-in-place method in which a foaming composition is injected into a cavity or mold and freely foamed.

[0223] In the spray method, the polyisocyanate (I) and other components, such as polyol (P), can be prepared separately and then sprayed onto the substrate while being mixed. Alternatively, the polyisocyanate (I) and other components, such as polyol (P), can be sprayed onto the substrate immediately after mixing.

[0224] Due to its high compressive strength, polyurethane foam can be appropriately used as a thermal insulation or sound insulation material. Examples of applications for thermal insulation or sound insulation materials include building components such as roofs, ceilings, and walls of buildings; household appliances such as refrigerators and water heaters; vehicles such as automobiles, airplanes, and ships; and pipes and tanks.

[0225] Example

[0226] The present invention will be described in more detail below using examples, but the present invention is not limited to the examples.

[0227] (Synthesis of polyester polyol (P1))

[0228] Examples A1 to A6, and Comparative Examples A1, A2, and A4

[0229] Tall rosin (a) and tall fatty acids (b) were each supplied to the reactor in the amounts specified in Table 1, and stirred uniformly at 175°C under a nitrogen atmosphere to obtain a solution. Next, maleic anhydride (c1) was supplied to the reactor in the amounts specified in Table 1, and the reactor was heated at 200°C for 1 hour to induce the Diels-Alder reaction and the olefin reaction. Diethylene glycol (d1), glycerol (d2), and 1,6-hexanediol were each supplied to the reactor in the amounts specified in Table 1, followed by isophthalic acid or phthalic anhydride in the amounts specified in Table 1 to obtain a mixture. This mixture was heated to 245°C, and then 0.1 parts by weight of magnesium acetate was supplied to the reactor. The mixture was then heated to 250°C, and an esterification reaction was carried out until the acid value of the mixture was below 2.0 mg KOH / g. The mixture was cooled to 235°C, and excess diethylene glycol (d1) was removed from the mixture under vacuum. This yielded a polyester polyol (P1).

[0230] Tall rosin (a) contains 40.2% by mass of abietic acid, 14.5% by mass of longleaf abietic acid and 4.9% by mass of neorosinic acid as resin acids (a1) with conjugated double bonds, and 0.4% by mass of piratic acid and 23.2% by mass of dehydrorosinic acid as resin acids (a2).

[0231] Tall oil fatty acids (b) contain 44.8% by mass of oleic acid and 28.8% by mass of linoleic acid as 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 saturated fatty acids (b2).

[0232] Glycerol (d2) is derived from biomass. Glycerol (d2) is obtained by hydrolyzing triglycerides contained in oils and fats.

[0233] Comparative Example A3

[0234] As the polyester polyol (P1), a fossil-derived polyester polyol (trade name "STEPANPOL (registered trademark) PS2352", available from Stepan Corporation) is used. The fossil-derived polyester polyol is obtained through the esterification reaction of fossil-derived phthalic anhydride with fossil-derived diethylene glycol. The raw material used for the polyester polyol is not biomass.

[0235] (evaluate)

[0236] The hydroxyl value, viscosity at 23°C, and number-average molecular weight of the polyester polyol (P1) were measured using the method described above. The results are shown in Table 1.

[0237] For the polyester polyols (P1) of each embodiment and comparative example, the compatibility with cyclopentane (boiling point: 49°C), isopentane (boiling point: 28°C), or cis-1,1,1,4,4,4-hexafluorobut-2-ene (boiling point: 33 to 33.5°C) as blowing agents was evaluated by the following procedure. The results are shown in Table 1.

[0238] Under an atmosphere of 23°C, 100 parts by weight of polyester polyol (P1) were placed in a vial. Next, 20 parts by weight of cyclopentane, 10 parts by weight of isopentane, or 25 parts by weight of cis-1,1,1,4,4,4-hexafluorobut-2-ene were added to the vial as a blowing agent. The vial was then sealed. The mixture in the vial was uniformly mixed by stirring with a vortex mixer. After 48 hours, the presence or absence of phase separation in the mixture in the vial was visually confirmed and evaluated according to the following evaluation criteria.

[0239] <Evaluation Criteria>

[0240] "++": The mixture is clear and there is no phase separation.

[0241] "+": The mixture shows no phase separation and is almost clear. No problems in practical use.

[0242] "+ / -": The mixture has not undergone phase separation, but it is turbid. Phase separation is likely to occur subsequently.

[0243] "-": Phase separation has occurred.

[0244] (Manufacturing of polyisocyanurate foam)

[0245] Examples B1 to B7 and Comparative Examples B1 to B4

[0246] In a reactor, 0.7 parts by weight of an amine catalyst (trade name "Niax C-5", available from Momentive), 4 parts by weight of a trimerizing catalyst (a solution containing 50% by weight or more potassium 2-ethylhexanoate, trade name "Niax K-ZeroG", available from Momentive), 1 part by weight of water, 2 parts by weight of a surfactant as a foam stabilizer (trade name "Niax L-5466", available from Momentive), and 15 parts by weight of a flame retardant (tris(2-chloro-1-methylethyl) phosphate, trade name "Roflam P", available from PCC Rokita SA) are added and mixed uniformly to obtain an additive composition.

[0247] Next, 100 parts by weight of polyol (P) and 18 parts by weight of cyclopentane were added to the reactor, and the mixture was stirred at 1,000 rpm for 20 seconds. The polyol (P) comprised the polyester polyols (P1) of Examples A1 to A6 and Comparative Examples A1 to A4 in the mixing amounts shown in Table 2. Polymethylene diphenyl diisocyanate (trade name "Suprasec 5025", available from Huntsman) was added to the reactor in the mixing amounts shown in Table 2, and the mixture was stirred at 2,000 rpm for 6 seconds. As a result, a foamed composition with an isocyanate index of 250 was obtained. The foamed composition was fed into an aluminum tray and foamed, then heated in an oven at 70°C for 1 hour. Thus, polyisocyanurate foam was obtained.

[0248] In Comparative Example B1, the polyester polyol (P1) of Comparative Example A1 was used as the polyol (P). Because the polyester polyol (P1) of Comparative Example A1 has low compatibility with the blowing agent, phase separation occurred in the foaming composition. Therefore, in Comparative Example B1, polyisocyanurate foam was not produced.

[0249] The compressive strength of polyisocyanurate foam in the thickness direction was measured using the method described above. The results are shown in Table 2. The expansion ratio and closed-cell ratio of polyisocyanurate foam are also shown in Table 2.

[0250] [Table 1]

[0251]

[0252] [Table 2]

[0253]

[0254] Industrial applicability

[0255] This invention provides a polyester polyol that has high compatibility with various blowing agents and can be used to manufacture polyurethane foams with reduced compressive strength (even when using biomass raw materials). Therefore, the polyisocyanate is preferably used as the polyol for manufacturing polyurethane foam.

Claims

1. A polyester polyol for polyurethane foam, the polyester polyol comprising a polyester polyol as a reaction product of raw material compounds, the raw material compounds containing: a rosin (a) containing a resin acid having a conjugated double bond (al); a biomass-derived fatty acid (b) containing an unsaturated fatty acid (bl); an α,β-unsaturated carboxylic acid (c); and a polyol (d) containing a diol having an ether bond (dl).

2. The polyester polyol according to claim 1, wherein a weight ratio [(a) / (b)] of the rosin (a) to the biomass-derived fatty acid (b) in the raw material compounds is 0.13 or greater and 2.00 or less.

3. The polyester polyol according to claim 1, wherein a weight ratio [(c) / (a)] of the α,β-unsaturated carboxylic acid (c) to the rosin (a) in the raw material compounds is 0.15 or greater and 2.00 or less.

4. The polyester polyol according to claim 1, wherein a weight ratio [(c) / (a + b)] of the α,β-unsaturated carboxylic acid (c) to a total amount of the rosin (a) and the biomass-derived fatty acid (b) in the raw material compounds is 0.05 or greater and 0.45 or less.

5. The polyester polyol according to claim 1, wherein a weight ratio [(dl) / (a + b)] of the diol having an ether bond (dl) to a total amount of the rosin (a) and the biomass-derived fatty acid (b) in the raw material compounds is 0.30 or greater and 2.00 or less.

6. The polyester polyol according to claim 1, wherein the raw material compounds further contain an aromatic polycarboxylic acid (e).

7. The polyester polyol according to claim 6, wherein a weight ratio [(e) / (a + b)] of the aromatic polycarboxylic acid (e) to a total amount of the rosin (a) and the biomass-derived fatty acid (b) in the raw material compounds is 0.05 or greater and 0.35 or less.

8. A polyurethane foam, which is a foam of a foamable composition containing a polyol (P), a polyisocyanate (I), and a blowing agent, wherein the polyol (P) comprises the polyester polyol according to any one of claims 1 to 7.

9. A method for producing a polyester polyol for polyurethane foam, comprising a step of reacting raw material compounds containing: a rosin (a) containing a resin acid having a conjugated double bond (al); a biomass-derived fatty acid (b) containing an unsaturated fatty acid (bl); an α,β-unsaturated carboxylic acid (c); and a polyol (d) containing a diol having an ether bond (dl) to obtain a polyester polyol.

10. The method for producing a polyester polyol for polyurethane foam according to claim 9, comprising: ​ ​ ​ ​ ​ ​ ​ ​ ​ a step of performing Diels-Alder reaction or ene reaction of rosin (a) containing a resin acid (al) having a conjugated double bond and a biomass-derived fatty acid (b) containing an unsaturated fatty acid (bl) with an α,β-unsaturated carboxylic acid (c) to obtain an adduct of the resin acid (al) and the α,β-unsaturated carboxylic acid (c), and an adduct of the unsaturated fatty acid (bl) and the α,β-unsaturated carboxylic acid (c), and a step of performing esterification reaction of the adduct of the resin acid (al) and the α,β-unsaturated carboxylic acid (c) and the adduct of the unsaturated fatty acid (bl) and the α,β-unsaturated carboxylic acid (c) with a polyol (d) containing a diol (dl) having an ether bond to obtain a polyester polyol.

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