Heat storage material, battery pack, composition, and composition kit

Abstract

This heat storage material contains a polyurethane. The polyurethane undergoes a solid phase-solid phase phase transition in a process at 20-80°C in differential scanning calorimetric measurements. The enthalpy change amount associated with the phase transition is 20 J / g or more. The combustion time of a test piece in the following measurement method is 60 seconds or less. (Measurement method) A test piece (125 mm×13 mm×2.0 mm) is attached vertically to a clamp, a flame contact test is carried out for 10 seconds with a 20 mm flame, and the combustion time is measured.

Description

Heat storage material, battery pack, composition, composition kit

[0001] The present invention relates to a heat storage material.

[0002] Polyurethanes include thermoplastic polyurethanes, which soften and melt when heated and then solidify when cooled, and thermosetting polyurethanes, which harden when heated. Both types of polyurethanes have excellent elasticity, mechanical strength, low-temperature properties, abrasion resistance, weather resistance, and oil resistance, and are also highly processable and can be easily fabricated into a variety of shapes. As a result, they are widely used in industrial parts such as rolls and casters, automotive parts such as solid tires and belts, office equipment parts such as paper feed rolls and copier rolls, as well as sports and leisure goods.

[0003] In recent years, attention has been focused on polyurethanes for heat storage materials, which have heat storage capabilities, i.e., small changes in shape in response to changes in external temperature, and heat storage molded articles using such polyurethanes. Improvement of heat storage performance, suppression of shape changes due to heating and cooling, and heat resistance have long been issues to be resolved for polyurethanes for heat storage materials.

[0004] For example, Patent Document 1 discloses a polyurethane for heat storage material containing a structural unit (A) derived from an aromatic compound having multiple isocyanate groups, a structural unit (B) derived from a polyol and / or polyamine, and a structural unit (C) derived from a polyalkylene ether glycol. Specifically, it discloses that a polyurethane using a polyalkylene ether glycol as a production raw material for the polyurethane exhibits heat storage properties.

[0005] Japanese Patent Application Laid-Open No. 2022-011733

[0006] However, the polyurethane disclosed in Patent Document 1 has a low fusion enthalpy when used alone. Therefore, when combined with a flame retardant, the fusion enthalpy of the composition is relatively reduced by the amount of flame retardant, making it difficult to achieve both endothermic properties and flame retardancy.

[0007] The present inventors have conducted extensive research into the above-mentioned problems, and have found that they can solve the problems, thereby completing the present invention. The gist of the present invention is as follows: [1] A polyurethane containing a structural unit (A) derived from an aromatic polyisocyanate compound and a structural unit (B) derived from a polyol, wherein the structural unit (B) contains a structural unit represented by the following formula (1), and the aromatic isocyanate compound has an average functionality of 2.1 or more:

[0008] (In formula (1), R1 is one or more of a linear, branched, or cyclic aliphatic hydrocarbon group having from 2 to 18 carbon atoms, or an aromatic hydrocarbon group, which may have a heteroatom; and n is 1 to 50.)

[0009] [2] The polyurethane according to the above [1], wherein the number average molecular weight of the structural unit (B) is in the range of 1,000 to 10,000. [3] R in the structural unit (B) １

[0013] The polyurethane according to [1] or [2] above, wherein the main component is a linear, branched, or cyclic aliphatic hydrocarbon group having 5 or more carbon atoms. [4] A polyurethane comprising structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyalkylene ether glycol, wherein the polyurethane contains a metal component, the content of the metal component being 10 to 500 ppm by mass. [5] The polyurethane according to any one of [1] to [4] above, wherein the mass fraction of the structural units (B) is 50% by mass or more and 99% by mass or less, relative to the total mass of the structural units (A) and (B). [6] The polyurethane according to any one of [1] to [5] above, wherein the enthalpy of fusion in the range of 20°C to 80°C, as observed by differential scanning calorimetry, is 20 J / g or more. [7] The polyurethane according to any one of [1] to [6] above, wherein the structural unit (A) comprises a structural unit derived from polymethylene polyphenyl polyisocyanate. [8] The polyurethane according to any one of [1] to [7] above, wherein the isocyanate index, which is the ratio of the isocyanate group equivalent (II) of the structural unit (A) to the hydroxyl group equivalent (I) of the structural unit (B), satisfies 0.4≦(II) / (I)≦1.1. [9] The polyurethane according to any one of [1] to [8] above, having a melting temperature of 20 to 80°C.

[10] A heat storage material comprising the polyurethane according to any one of [1] to [9] above.

[11] An electrical appliance comprising the polyurethane according to any one of [1] to [9] above.

[12] A battery pack comprising the polyurethane according to any one of [1] to [9] above.

[13] A semiconductor product comprising the polyurethane according to any one of [1] to [9] above.

[14] A heat storage material containing polyurethane and a flame retardant, wherein the polyurethane contains structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyalkylene ether glycol, and the burning time of a test piece measured by the following measurement method is 60 seconds or less. <Measurement method> The test piece (125 mm x 13 mm x 1.5 mm) is attached vertically to a clamp and exposed to a 20 mm flame for 10 seconds, and the burning time is measured.

[15] A heat storage material containing polyurethane, wherein the polyurethane contains structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyalkylene ether glycol, and wherein the tensile shear bond strength measured by the following measurement method is 0.40 MPa or more. (Measurement method) Two adherend test pieces measuring 25 mm x 100 mm x 1.6 mm were prepared, and the heat storage material was applied to the overlapping portions of the adherend test pieces so that the overlapping length of the adherend test pieces was 12.5 mm and the thickness of the heat storage material was 0.2 mm, and the heat storage material was cured. Each adherend test piece was fixed at a region 50 mm or more away from the edge of the overlapping portion as a gripping portion, and tested at a tensile speed of 5 mm / min, and the tensile shear load value obtained was measured as the adhesive area (mm ２ ) to obtain the value of the tensile shear adhesive strength.

[16] The heat storage material according to the above

[14] or

[15] , wherein the polyurethane has a melting point of 20 to 80°C.

[17] The heat storage material according to any one of the above

[14] to

[16] , wherein the mass fraction of the structural unit (B) is 50% by mass or more and 99% by mass or less with respect to the total mass of the structural units (A) and (B).

[18] The heat storage material according to any one of the above

[14] to

[17] , wherein the polyurethane has a melting enthalpy of 20 J / g or more at 20 to 80°C as observed by differential scanning calorimetry.

[19] The heat storage material according to any one of the above

[14] to

[18] , wherein the structural unit (A) includes a structural unit derived from polymethylene polyphenyl polyisocyanate.

[20] The heat storage material according to any one of the above

[15] to

[19] , further comprising an adhesive, the content of which is 0.001 to 5.0 mass%.

[21] The heat storage material according to any one of the above

[15] to

[19] , further comprising an adhesive, the adhesive comprising a silane coupling agent.

[22] The heat storage material according to any one of the above

[15] to

[19] , further comprising an adhesive, the adhesive comprising a silane coupling agent represented by the following formula (2): X-Si-Y １ Y ２ Y ３ (2) (In formula (2), X is an organic group, and Y １ ~Y ３are each independently a group capable of forming a bond with an adherend.)

[23] The heat storage material according to the above

[22] , wherein X in the formula (2) is a group capable of forming a bond with the partial structure of the polyurethane.

[24] The heat storage material according to the above

[22] or

[23] , wherein X in the formula (2) is at least one group selected from the group consisting of a vinyl group, an epoxy group, a (meth)acrylic group, an amino group, an isocyanate group, an isocyanurate group, a mercapto group, a polysulfide group, a ureido group, a hydrocarbon group which may have a fluorine atom, a carboxyl group, and a phosphoryl group.

[25] The heat storage material according to any one of the above

[22] to

[24] , wherein Y in the formula (2) is at least one group selected from the group consisting of a hydroxy group, an alkoxy group, an acyloxy group, a halogeno group, and a siloxane precursor group.

[26] The heat storage material according to any one of

[22] to

[25] above, wherein the ratio of the total number of equivalents of isocyanate groups to the total number of equivalents of active hydrogen groups contained in the structural unit (A), the structural unit (B), and the adhesive is 0.4 to 1.1.

[27] The heat storage material according to any one of

[15] to

[25] above, wherein the heat storage material has a melting enthalpy of 20 J / g or more at 20 to 80°C as observed by differential scanning calorimetry.

[28] A composition comprising an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and an adhesive, wherein the ratio of the total number of equivalents of isocyanate groups to the total number of equivalents of active hydrogen groups contained in the aromatic polyisocyanate compound having an average functionality of 2.1 or more, the polyalkylene ether glycol, and the adhesive is 0.4 to 1.1.

[29] A composition kit comprising: a first container filled with a composition (a) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more, and a second container filled with a polyol composition (b) containing a polyalkylene ether glycol and an adhesive.

[30] A composition kit comprising: a first container filled with a composition (a) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more and an adhesive, and a second container filled with a polyol composition (b) containing a polyalkylene ether glycol.

[31] A supply form of a two-component curing composition comprising a first container filled with a composition (a) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more, and a second container filled with a polyol composition (b) containing a polyalkylene ether glycol and a flame retardant.

[32] A method for producing a heat storage material, comprising curing a composition containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and an adhesive, wherein the ratio of the total number of equivalents of isocyanate groups to the total number of equivalents of active hydrogen groups contained in the aromatic polyisocyanate compound having an average functionality of 2.1 or more, the polyalkylene ether glycol, and the adhesive is adjusted to 0.4 to 1.1. [A1] A heat storage material containing polyurethane, wherein the polyurethane undergoes a solid-solid phase transition in differential scanning calorimetry between 20 and 80°C, the enthalpy change associated with the phase transition is 20 J / g or more, and the burning time of a test piece measured by the following method is 60 seconds or less. (Measurement Method) A test piece (125 mm x 13 mm x 2.0 mm) is attached vertically to a clamp, and exposed to a 20 mm flame for 10 seconds, and the burning time is measured. [A2] The heat storage material according to [A1] above, wherein the polyurethane contains structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyol having a melting point of 30°C or higher. [A3] The heat storage material according to [A2] above, wherein the mass fraction of the structural units (B) is 50% by mass or more and 99% by mass or less relative to the total mass of the structural units (A) and (B). [A4] The heat storage material according to [A2] or [A3] above, wherein the structural units (A) contain structural units derived from polymethylene polyphenyl polyisocyanate. [A5] The heat storage material according to any one of [A2] to [A4] above, wherein the structural units (B) contain structural units derived from polyalkylene ether glycol.[A6] The heat storage material according to any one of [A1] to [A5] above, wherein the polyurethane comprises structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyol having a melting point of 30°C or higher, and wherein an isocyanate index, which is the ratio of the isocyanate group equivalent (II) of the structural unit (A) to the hydroxyl group equivalent (I) of the structural unit (B), satisfies 0.4≦(II) / (I)≦1.1. [A7] The heat storage material according to any one of [A1] to [A6] above, further comprising a flame retardant, wherein the melting point of the flame retardant is 200°C or lower. [A8] The heat storage material according to any one of [A1] to [A7] above, further comprising a flame retardant, wherein the melting point of the flame retardant is 30 to 200°C. [A9] The heat storage material according to any one of [A1] to [A8] above, further comprising a flame retardant, wherein the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyalkylene ether glycol is 0 to 100°C. [A10] The heat storage material according to any one of [A1] to [A9] above, further comprising a flame retardant, wherein the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyurethane is 0 to 100°C. [A11] The heat storage material according to any one of [A1] to [A10] above, further comprising a flame retardant, wherein the ratio of the content of elements corresponding to the flame retardant in the heat storage material based on XPS measurement to the content based on XRF measurement, as measured by the following method, is 0.5 to 1.5. (Measurement Method) A test piece measuring 10 mm x 10 mm x 5.0 mm is cut from the heat storage material, and the content of elements corresponding to the flame retardant is measured using an X-ray fluorescence analyzer (XRF) and an X-ray photoelectron spectroscopy (XPS). [A12] The heat storage material according to any one of [A1] to [A11] above, further comprising a flame retardant, and having a coefficient of variation of the content of elements corresponding to the flame retardant in the heat storage material of 0.15 or less, as measured by the following method. (Measurement method) Five test pieces measuring 10 mm x 10 mm x 5.0 mm are cut out from the heat storage material, and the content of elements corresponding to the flame retardant is measured using an X-ray photoelectron spectroscopy (XPS). [A13] The heat storage material according to any one of [A1] to [A12] above, having a tensile shear bond strength of 0.40 MPa or more, as measured by the following method.(Measurement method) Two adherend test pieces measuring 25 mm × 100 mm × 1.6 mm were prepared, and the heat storage material was applied to the overlapping portions of the adherend test pieces so that the overlapping length of the adherend test pieces was 12.5 mm and the thickness of the heat storage material was 0.2 mm, and then cured. An area 50 mm or more away from the edge of the overlapping portion of each adherend test piece was fixed as a gripping portion, and the test was carried out at a tensile speed of 5 mm / min, and the obtained tensile shear load value was recorded as an adhesive area (mm ２ ) to obtain the value of the tensile shear adhesive strength. [A14] A battery pack comprising a plurality of unit cells and the heat storage material according to any one of [A1] to [A13] above. [A15] A composition comprising an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and a flame retardant, wherein the mass fraction of the polyalkylene ether glycol is 50% by mass or more and 99% by mass or less with respect to the total mass of the aromatic polyisocyanate compound having an average functionality of 2.1 or more and the polyalkylene ether glycol, and the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyalkylene ether glycol is 0 to 100°C. [A16] The composition according to [A15] above, wherein the melting point of the polyalkylene ether glycol is 30°C or more and 100°C or less. [A17] The composition according to [A15] or [A16] above, wherein the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyalkylene ether glycol is 0 to 60° C. [A18] The composition according to any one of [A15] to [A17] above, wherein the melting point of the polyalkylene ether glycol is 30 to 100° C., and the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyalkylene ether glycol is 0 to 60° C. [A19] A composition kit comprising: a first container filled with a composition (a) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more; and a second container filled with a polyol composition (b) containing a polyalkylene ether glycol and a flame retardant, wherein the ratio of the volume of the second container to the volume of the first container is 5 to 15.

[0010] According to the present invention, it is possible to provide a heat storage material that is both heat absorbing and flame retardant.

[0011] 1 is a diagram showing a case where a support structure in a battery pack according to an embodiment of the present invention includes a plurality of recesses; FIG. 2 is a diagram showing a case where a support structure in a battery pack according to an embodiment of the present invention includes a plurality of hollow portions; FIG. 3 is a diagram showing a battery pack and a battery pack according to an embodiment of the present invention; FIG. 4 is a diagram showing a DSC curve during temperature increase in Experimental Example 3; FIG. 5 is a diagram showing a DSC curve during temperature decrease in Experimental Example 3; FIG. 6 is a conceptual diagram showing a 1 / 6 cake cut model;

[0012] In this specification, when a numerical value or physical property value is enclosed before and after the symbol "to", the values ​​before and after the symbol are included. For example, "A to B μm" means "A μm or more and B μm or less". Numerical ranges such as "A to B", "A or more", and "B or less" disclosed in this specification disclose numerical ranges with arbitrarily selected upper and lower limits. "A or more" means "greater than A and / or A", and also discloses the numerical range "greater than A". Similarly, "B or less" means "smaller than B and / or B", and also discloses the numerical range "smaller than B".

[0013] [Polyurethane] A polyurethane according to one embodiment of the present invention undergoes a solid-solid phase transition in differential scanning calorimetry at 20 to 80°C, and the enthalpy change associated with the phase transition is 20 J / g or greater. The polyurethane contains structural units derived from a polyisocyanate and structural units derived from a polyol.

[0014] The term "endothermic peak temperature" refers to the peak temperature of the solid-solid phase transition when the temperature is increased by differential scanning calorimetry. The term "exothermic peak temperature" refers to the peak temperature of the solid-solid phase transition when the temperature is decreased by differential scanning calorimetry. The term "solid-solid phase transition" refers to a phase transition from a solid phase to a non-fluid state. It also includes a phase transition from a solid phase to an intermediate phase between a solid phase and a liquid phase, as long as the solid phase is non-fluid. Here, the term "solid phase" refers to a gel fraction of 70% or more. Typically, the solid-solid phase transition includes a phase transition accompanied by exothermic and endothermic events. The exothermic phase transition temperature can be confirmed from the exothermic peak temperature in differential scanning calorimetry, and the endothermic phase transition temperature can be confirmed from the endothermic peak temperature in differential scanning calorimetry. The term "structural unit" refers to a structure derived from either an isocyanate or a polyol in the polymer structure, rather than a single urethane bond. The "average number of functional groups" refers to the number of isocyanate groups per isocyanate compound forming a structural unit. To induce a solid-solid phase transition, it is desirable to introduce crosslinking points into the polymer structure and include crystalline segments in the molecular chain between the crosslinking points. The melting of the crystalline segments changes the crystalline structure of the polymer, which in turn causes an enthalpy change. Furthermore, the presence of crosslinking points in the polymer makes it easier for the polymer to maintain its solid phase as a whole.

[0015] A polyurethane according to one embodiment of the present invention contains, as a polyisocyanate component, structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more, and structural units (B) derived from a polyol.

[0016] <Structural Unit (A)> The structural unit (A) constituting the polyurethane according to the present invention is derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more.

[0017] (Aromatic Polyisocyanate Compound with Average Functionality of 2.1 or More) The structural unit (A) constituting the polyurethane of the present invention is derived from an aromatic polyisocyanate compound. Use of an aromatic polyisocyanate compound facilitates control of the curing time. Furthermore, the polyurethane of the present invention has an average functionality of 2.1 or more of isocyanate groups in the polyurethane. To obtain such a polyurethane, it is essential that the isocyanate used as a raw material for producing the polyurethane is an aromatic compound having an average functionality of 2.1 or more of isocyanate groups. By using such a compound, the average functionality of the isocyanate groups in the polyurethane can be increased to 2.1 or more. By increasing the average functionality of the isocyanate groups of the aromatic polyisocyanate compound to 2.1 or more, the polyurethane can be made non-fluid (solid). From the above perspectives, the average functionality of the isocyanate groups of the aromatic polyisocyanate compound is preferably 2.2 or more, more preferably 2.3 or more, even more preferably 2.5 or more, and particularly preferably 2.7 or more. The average functionality of the isocyanate groups can be controlled by introducing crosslinking points. There is no particular upper limit to the average number of functional groups of the isocyanate groups of the aromatic polyisocyanate compound. However, from the viewpoints of low viscosity, ease of handling, and ease of achieving the effects of the present invention, the upper limit is usually 8 or less, preferably 4 or less, and more preferably 3 or less.

[0018] The average functionality of the isocyanate groups can be calculated from the isocyanate (NCO) content using the following formula: The isocyanate content can be determined by back titration with dibutylamine as specified in JIS K 1603-1:2007 Method B. Average functionality of isocyanate groups = NCO content × (4.2 / 1000) × molecular weight

[0019] The average number of functional groups of the isocyanate groups in the polyurethane according to the present invention is the same as that of the samples containing the polymer hydrolysate and heavy solvent. １ Quantitative determination is performed by H-NMR measurement. The average number of functional groups is １For example, in the case of polymethylene polyphenyl polyisocyanate described below, the ratio is calculated from the ratio of the peak area corresponding to the terminal amine to the peak area corresponding to the methylene.

[0020] Examples of the aromatic polyisocyanate compound include polymethylene polyphenyl polyisocyanate (polymeric MDI), adducts obtained by adding a polyhydric alcohol to xylylene diisocyanate (XDI), adducts obtained by adding a polyhydric alcohol to toluene diisocyanate (2,4-toluene diisocyanate, 2,6-toluene diisocyanate, hereinafter sometimes referred to as "TDI"), and isocyanurates and biurets derived from TDI. Among these, polymethylene polyphenyl polyisocyanate is more preferred as the aromatic polyisocyanate compound from the viewpoints of its reactivity with polyols described below, the high curability of the resulting polyurethane, and its industrial availability in large quantities at low cost.

[0021] (Other Polyisocyanate Compounds) In the present invention, polyisocyanate compounds other than the aromatic polyisocyanate compounds having an average functionality of 2.1 or more can be used to the extent that the effects of the present invention are not impaired. Examples of such polyisocyanate compounds include bifunctional aromatic polyisocyanate compounds, aliphatic polyisocyanate compounds, and alicyclic polyisocyanate compounds. Examples of bifunctional aromatic polyisocyanate compounds include aromatic diisocyanate compounds such as xylylene diisocyanate, 4,4'-diphenyl diisocyanate, toluene diisocyanate (2,4-toluene diisocyanate, 2,6-toluene diisocyanate), m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, 3,3'-dimethyl-4,4'-biphenylene diisocyanate, polymethylene polyphenyl isocyanate, phenylene diisocyanate, and m-tetramethylxylylene diisocyanate. Examples of alicyclic polyisocyanates include isophorone diisocyanate (hereinafter, can be referred to as "IPDI"), hydrogenated xylylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate (hereinafter, can be referred to as "H12MDI"), 1,4-cyclohexane diisocyanate, methylcyclohexylene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, etc. Examples of aliphatic polyisocyanates include tetramethylene diisocyanate, dodecamethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, etc. These may be used alone or in combination of two or more.The content of other polyisocyanate compounds is 10% by mass or less, preferably 5% by mass or less, and most preferably 0% by mass, of the total polyisocyanate compounds used in the present invention.

[0022] <Structural Unit (B)> The structural unit (B) constituting the polyurethane according to the present invention is derived from a polyol. One embodiment of the structural unit (B) contains a structural unit represented by the following formula (1). The carbonate bond of a polycarbonate polyol is less likely to be cleaved than polyols used as raw materials for ordinary polyurethanes. When a polycarbonate polyol is used as the structural unit (B) constituting the polyurethane according to the present invention, a polyurethane can be provided that can maintain high heat storage performance even when used at high temperatures, has no change in the usable temperature range, has excellent heat resistance, and further, does not leak polyol, resulting in excellent safety.

[0023]

[0024] (In formula (1), R １ represents one or more of a linear, branched, or cyclic aliphatic hydrocarbon group or an aromatic hydrocarbon group having from 2 to 18 carbon atoms, and may have a heteroatom; and n is 1 to 50.

[0025] R １ has a carbon number of 2 or more and 18 or less, preferably 3 or more and 16 or less, and more preferably 5 or more and 12 or less. １ However, it is preferable that the main component is a linear, branched or cyclic aliphatic hydrocarbon group having 5 or more carbon atoms. １ Specific examples of the linear aliphatic hydrocarbon group in R include an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, a hexamethylene group, a heptamethylene group, an octamethylene group, a nonabutylene group, a decabutylene group, a dodecabutylene group, a tetradecamethylene group, and a pentadecamethylene group. １Specific examples of the branched aliphatic hydrocarbon group in R include an isopropylene group, an isobutylene group, a tert-butylene group, an isopentylene group, a tert-pentylene group, a 2,2-dimethyltrimethylene group, an isohexylene group, a 2-methylpentylene group, a 3-methylpentylene group, an isoheptylene group, an isooctylene group, an isononylene group, a 2,4-diethylpentylene group, a 2-butyl-2-ethylpropylene group, and an isodecylene group. １ Specific examples of the cycloaliphatic hydrocarbon group in R include a cyclobutylene group, a cyclopentylene group, a cyclohexylene group, and a cyclooctylene group. １ Specific examples of the aromatic hydrocarbon group in (a) include a phenylene group and a naphthylene group. Among these, a linear aliphatic hydrocarbon group is more preferred because it increases the enthalpy of fusion. n is 1 to 50, preferably 3 to 40, more preferably 5 to 30, and even more preferably 7 to 25.

[0026] The number average molecular weight of the polyol that becomes the structural unit (B) is preferably 1,000 or more and 10,000 or less. A molecular weight of 1,000 or more results in high crystallinity and a large enthalpy of fusion. On the other hand, a number average molecular weight of 10,000 or less results in low viscosity and easy handling. From the above viewpoints, the number average molecular weight of the polyol that becomes the structural unit (B) is more preferably 1,500 to 5,000, and even more preferably 1,800 to 4,000.

[0027] In the polyurethane of the present invention, the mass fraction of the structural unit (B) represented by the above formula (1) is preferably 50% by mass or more and 99% by mass or less, based on the total mass of the structural units (A) and (B). When the mass fraction of the structural unit (B) represented by the above formula (1) is 50% by mass or more, the fusion enthalpy becomes large. On the other hand, when the mass fraction of the structural unit (B) represented by the above formula (1) is 99% by mass or less, it is possible to maintain a solid form even when melted. From the above viewpoints, the mass fraction of (B) represented by the above formula (1) is more preferably 70% by mass or more and 98% by mass or less, and even more preferably 89% by mass or more and 97% by mass or less.

[0028] Another embodiment of the structural unit (B) derived from a polyol is derived from a polyol having a melting point of 30° C. or higher. Preferably, it is derived from a polyalkylene ether glycol. That is, in this embodiment, the polyurethane contains the structural unit (B) derived from a polyalkylene ether glycol.

[0029] (Polyalkylene ether glycol) In the present invention, the repeating unit in the main skeleton of the polyalkylene ether glycol may be either a saturated hydrocarbon or an unsaturated hydrocarbon, and may be linear, branched, or cyclic. However, from the viewpoint of improving heat storage, saturated hydrocarbons are preferred, and linear structures are preferred. That is, the structural unit (B) preferably has a linear structure and preferably has no unsaturated bonds. The melting point of the polyalkylene ether glycol is preferably 30°C or higher and 100°C or lower. By having a melting point within the above range, the heat storage properties of the polyurethane are improved. From the viewpoint of improving this effect, the lower limit is preferably 35°C, more preferably 40°C, even more preferably 45°C, particularly preferably 50°C, and particularly preferably 55°C. In addition, polyalkylene ether glycols using raw materials of biological origin can also be used.

[0030] Examples of repeating units in the main skeleton include a 1,2-ethylene glycol unit, a 1,2-propylene glycol unit, a 1,3-propanediol (trimethylene glycol) unit, a 2-methyl-1,3-propanediol unit, a 2,2-dimethyl-1,3-propanediol unit, a 1,4-butanediol (tetramethyl glycol) unit, a 2-methyl-1,4-butanediol unit, a 3-methyl-1,4-butanediol unit, a 3-methyl-1,5-pentanediol unit, a neopentyl glycol unit, a 1,6-hexanediol unit, a 1,7-heptanediol unit, a 1,8-octanediol unit, a 1,9-nonanediol unit, a 1,10-decanediol unit, and a 1,4-cyclohexanedimethanol unit.

[0031] Among these, from the viewpoint of improving the heat storage property, heat resistance, and moldability (hereinafter sometimes referred to as "heat storage property, etc.") of the polyurethane, it is preferable that the polyurethane contains polyethylene glycol whose repeating unit is a 1,2-ethylene glycol unit. In other words, it is preferable that the polyalkylene ether glycol contains polyethylene glycol. From the viewpoint of further improving the effects of the heat storage property, etc., the content of polyethylene glycol is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and particularly preferably 100% by mass, based on the total amount of polyalkylene ether glycol.

[0032] The number average molecular weight of the structural unit (B) derived from the polyalkylene ether glycol is preferably in the range of 1,000 or more and 10,000 or less. When the number average molecular weight is within the above range, the polyurethane has good heat storage properties and heat resistance, and is excellent in moldability. From the viewpoint of improving this effect, the lower limit is more preferably 1,400, even more preferably 2,000, particularly preferably 2,500, and particularly preferably 3,000. From the same viewpoint, the upper limit is more preferably 9,000, even more preferably 6,000, and particularly preferably 4,000. The number average molecular weight of the structural unit (B) derived from the polyalkylene ether glycol can be determined from the hydroxyl value obtained by the acetic anhydride pyridine method. Furthermore, when it is assumed that the polyurethane of the present invention is used for a battery, from the viewpoint of efficiently absorbing heat from the battery, the number average molecular weight of the structural unit (B) is more preferably 1,400 or more and 10,000 or less, even more preferably 2,000 or more and 10,000 or less, even more preferably 3,000 or more and 10,000 or less, and particularly preferably 3,400 or more and 10,000 or less.

[0033] Furthermore, in the polyurethane of the present invention, the mass fraction of the structural unit (B) relative to the total mass of the structural units (A) and (B) is preferably 50% by mass or more and 99% by mass or less. When the mass fraction of the structural unit (B) relative to the total mass of the structural units (A) and (B) is within the above range, the enthalpy of fusion can be maximized. From the viewpoint of enhancing this effect, the lower limit is preferably 60% by mass, more preferably 70% by mass, even more preferably 80% by mass, and even more preferably 90% by mass, and the upper limit is preferably 98% by mass. The number average molecular weight of the structural unit (B) derived from polyalkylene ether glycol is quantified by gel permeation chromatography on a solution containing a polymer hydrolysate. A Waters Alliance 2695, 2414 (refractometer), or 2996 (PDA) equipped with a gel permeation chromatograph connected to a photodiode array (PDA) detector is used. Using sodium polystyrene sulfonate with peak top molecular weights of 206, 4300, 6800, 17000, 32000, 77000, 15000, and 2600000 as standard samples, a calibration curve of number average molecular weight versus retention time is prepared. The retention time of the obtained chromatogram is converted into the number average molecular weight in terms of sodium polystyrene sulfonate.

[0034] The polyalkylene ether glycol used in the present invention usually contains a small amount of water, and the water content is preferably 1000 to 10000 ppm, particularly preferably 1500 to 8000 ppm, and even more preferably 2000 ppm to 5000 ppm. Within the above range, foaming is suppressed and heat uniformity and thermal conductivity can be maintained. The water content can be measured by the Karl Fischer method or the like.

[0035] (Other polyols) In addition to the above-mentioned polycarbonate polyols and polyalkylene ether glycols, other polyols may be used as the polyols used in the present invention to the extent that they do not impair the effects of the present invention.The other polyols are not particularly limited as long as they are used in ordinary polyurethane production, and examples thereof include polyester polyols and polycaprolactone polyols.These may be used alone or in combination of two or more.In addition, the content of other polyols is 10% by mass or less, preferably 5% by mass or less, and most preferably 0% by mass, of the total polyols used in the present invention.

[0036] <Metal Component> The polyurethane of the present invention can contain a metal component, and the content thereof is preferably 10 to 500 ppm by mass. When the metal component content is 500 ppm by mass or less, heat generation during the polyurethane production process can be suppressed, and runaway urethanization reaction can be suppressed. From the above perspectives, the metal component content is more preferably 300 ppm by mass or less, and even more preferably 100 ppm by mass or less. On the other hand, the lower the lower limit of the metal component content, the better, but the operations for reducing the metal component content are complicated, and excessive reduction is disadvantageous from the perspective of production costs. Therefore, the lower limit of the metal component content is 10 ppm by mass, more preferably 15 ppm by mass. The urethanization reaction during the polyurethane production process can sometimes go out of control depending on the reaction conditions, making it difficult to control the reaction. Furthermore, polyurethanes for heat storage materials that have high heat storage function and little change in shape in response to changes in external temperature require the urethane reaction to proceed gradually to prevent thermal non-uniformity during temperature rise, but there has been a problem in that thermal uniformity is insufficient and sufficient pot life cannot be ensured. By containing a metal component, the polyurethane of the present invention can prevent runaway urethane reaction under the above-mentioned conditions, suppress heat generation, and provide a polyurethane with a long pot life. In the present invention, examples of metal components include alkali metals such as potassium and sodium, which may be mixed in from polyol components, catalysts used in producing polyols, etc. In order to keep the metal component within the above range, methods such as purifying the polyol and adding a metal are available.

[0037] <Physical Properties of Polyurethane> The polyurethane according to the present invention preferably has a crystallization temperature of 0 to 60°C. The lower limit of the crystallization temperature is more preferably 10°C, even more preferably 15°C, even more preferably 20°C, and particularly preferably 25°C. The upper limit is more preferably 50°C, even more preferably 40°C. When the crystallization temperature is within the above range, heat and cold storage can be performed efficiently. Furthermore, when the polyurethane according to the present invention is used for a battery, the battery can efficiently absorb heat.

[0038] The polyurethane according to the present invention preferably has a melting point (melting temperature) of 20 to 80°C. The lower limit of the melting point is more preferably 20°C, even more preferably 30°C, even more preferably 40°C, and particularly preferably 45°C. The upper limit is more preferably 70°C, even more preferably 60°C. By having the melting point within the above range, heat and cold storage can be performed efficiently. Furthermore, when the heat storage material of the present invention is used for a battery, the battery can efficiently absorb heat.

[0039] In the polyurethane according to the present invention, the melting enthalpy in the range of 20°C to 80°C, as observed by differential scanning calorimetry, is preferably 20 J / g or more. A melting enthalpy of 20 J / g or more allows the polyurethane to be suitably used as a heat storage material. From the above viewpoints, the melting enthalpy in the range of 20°C to 80°C is more preferably 30 J / g or more, and even more preferably 35 J / g or more. There is no particular upper limit, and it may be, for example, 500 J / g or less.

[0040] (Isocyanate Index) The isocyanate index (NCO Index) of the polyurethane according to the present invention is the ratio of the isocyanate group equivalent (II) of the structural unit (A) to the hydroxyl group equivalent (I) of the structural unit (B). However, when an adhesive is included, the isocyanate index of the polyurethane is determined taking into account the functional groups of the adhesive. The isocyanate index is preferably 0.4≦(II) / (I)≦1.1. By having the aromatic isocyanate / crystalline polyol ratio within the above range, the polyurethane can have good heat storage properties and shape retention after melting. From the viewpoint of improving this effect, the lower limit is preferably 0.65, more preferably 0.70, and even more preferably 0.80. From the same viewpoint, the upper limit is preferably 1.10, more preferably 1.05, and even more preferably 1.00. The aromatic isocyanate / crystalline polyol ratio can be determined by nuclear magnetic resonance (NMR) analysis.

[0041] (Other Additives) Various additives can be added to the polyurethane of the present invention as long as they do not impair the effects. Examples of additives include antioxidants, heat stabilizers, light stabilizers, UV absorbers, fillers, neutralizers, lubricants, antifogging agents, antiblocking agents, slip agents, dispersants, colorants, flame retardants, antistatic agents, conductivity imparting agents, crosslinking agents, crosslinking aids, metal deactivators, molecular weight modifiers, antibacterial agents, mildewproofing agents, fluorescent brighteners, and light diffusing agents such as organic diffusing agents and inorganic diffusing agents. The antioxidant is not particularly limited as long as it does not impair the effects of the present invention, and examples include phenolic antioxidants and phosphite antioxidants. Adding an antioxidant can reduce the rate of enthalpy change before and after heat treatment. Specifically, it is preferable that the rate of enthalpy change ΔH at the polyurethane-derived peak after treatment at 100°C for 200 hours is 10% or less.

[0042] <Method for Producing Polyurethane> The polyurethane of the present invention can be produced by reacting a raw material, polycarbonate polyol or polyalkylene ether glycol, with an aromatic compound having an isocyanate group, preferably an aromatic polyisocyanate compound having an average functionality of 2.1 or more. It is preferable to use a catalyst during the reaction. The charged composition of the polyalkylene ether glycol and the aromatic polyisocyanate compound having an average functionality of 2.1 or more can be, for example, a stoichiometric ratio such that the polyurethane satisfies a predetermined isocyanate group equivalent / polyol hydroxyl group ratio. In other respects, the polyurethane can be produced by a conventional polyurethane formation reaction.

[0043] (Other Polyols) In the polyurethane-forming reaction when producing polyurethane, other polyols may be used in combination with polycarbonate polyol or polyalkylene ether glycol as needed. Here, the polyols other than polycarbonate polyol are not particularly limited as long as they are those used in normal polyurethane production, and examples thereof include polyester polyols and polycaprolactone polyols. Here, the mass ratio of polycarbonate polyol or polyalkylene ether glycol to the combined mass of polycarbonate polyol or polyalkylene ether glycol and other polyols is preferably 30% or more, more preferably 50% or more. When the mass ratio of polycarbonate polyol or polyalkylene ether glycol is equal to or greater than the above lower limit, the heat storage property of the polyurethane is improved.

[0044] (Equivalent ratio) The amount of aromatic polyisocyanate compound used is not particularly limited, but is preferably 0.4 equivalents or more and 1.1 equivalents or less, where N1 is the total number of hydroxyl groups in the polyol, N2 is the number of hydroxyl groups in the chain extender, and N3 is the total number of amino groups (N1 + N2 + N3) as 1 equivalent. A more preferred lower limit of the amount used is 0.65 equivalents, more preferably 0.70 equivalents, and even more preferably 0.80 equivalents. When the total is taken as 1 equivalent, the upper limit of the amount used is preferably 1.10 equivalents, more preferably 1.07 equivalents, even more preferably 1.05 equivalents, and even more preferably 1.00 equivalents.

[0045] By adjusting the amount of aromatic polyisocyanate compound used to be equal to or less than the upper limit, it is possible to suppress side reactions of unreacted isocyanate groups and prevent changes in hardness over time. On the other hand, by adjusting the amount used to be equal to or more than the lower limit, the molecular weight of the polyurethane becomes sufficiently high, making it difficult to melt even when heated, allowing a gel fraction of 70% or more to be maintained, and improving shape retention.

[0046] (Catalyst) A catalyst can be used when producing the polyurethane according to the present invention. The catalyst is not particularly limited as long as it can produce polyurethane, but organic catalysts are preferred, and examples thereof include amines and imidazoles. When an aromatic polyisocyanate compound is used, the use of an organic catalyst can improve the activity of the urethane-forming reaction, making it possible to control the curing time and productivity during production.

[0047] Examples of organic catalysts that can be used include base catalysts (basic compounds) such as amine catalysts (e.g., triethylenediamine, triethylamine, N-ethylmorpholine), imidazole catalysts (e.g., 1,2-dimethylimidazole), and acid catalysts (e.g., acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, sulfonic acid). Among these, base catalysts are preferred, nitrogen-containing compounds are more preferred, and at least one of an amine catalyst and an imidazole catalyst is more preferred, with at least one of triethylenediamine and imidazole being preferred. A single catalyst may be used, or two or more may be used in combination. From the viewpoint of controlling the curing time, it is preferable to use two or more organic catalysts. Furthermore, the amount of catalyst added is preferably 10 ppm to 1,000 ppm per 100 parts by mass of the total solids content in the composition for producing the polyurethane of the present invention. By adjusting the amount of catalyst added within the above range, polyurethane can be produced efficiently.

[0048] (Chain Extender) When producing the polyurethane according to the present invention, glycol or polyamine may be added as a chain extender to the raw materials for production to the extent that it does not adversely affect the physical properties. Specific examples thereof include linear diols such as ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol; 2-methyl-1,3-propanediol, 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 2-methyl-2-propyl-1,3-propanediol, and 2,4-heptanediol. diols having a branched chain such as diol, 1,4-dimethylolhexane, 2-ethyl-1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-methyl-1,8-octanediol, 2-butyl-2-ethyl-1,3-propanediol, and dimer diol; diols having an ether group such as diethylene glycol and propylene glycol; diols having an alicyclic structure such as 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and 1,4-dihydroxyethylcyclohexane diols having an aromatic group such as xylylene glycol, 1,4-dihydroxyethylbenzene, 4,4'-methylenebis(hydroxyethylbenzene); polyols such as glycerin, trimethylolpropane, pentaerythritol; hydroxyamines such as N-methylethanolamine, N-ethylethanolamine; ethylenediamine, 1,3-diaminopropane, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, 4,4'-diamino polyamines such as dicyclohexylmethane, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, 4,4'-diphenylmethanediamine, methylenebis(o-chloroaniline), xylylenediamine, diphenyldiamine, tolylenediamine, hydrazine, piperazine, and N,N'-diaminopiperazine; and the like.These glycols or polyamines may be used alone or in combination of two or more.

[0049] The amount of chain extender used is not particularly limited, but when the total number of hydroxyl groups in the polyol minus the number of isocyanate groups in the aromatic compound having an isocyanate group is taken as 1 equivalent, the lower limit of the amount used is preferably 0.7 equivalents, more preferably 0.8 equivalents, even more preferably 0.9 equivalents, and even more preferably 0.95 equivalents. The upper limit of the amount used is preferably 3.0 equivalents, more preferably 2.0 equivalents, even more preferably 1.5 equivalents, and even more preferably 1.1 equivalents. By using an amount of chain extender below the upper limit, it is possible to prevent the polyurethane from becoming difficult to dissolve in solvents and process. By using an amount above the lower limit, it is possible to prevent the polyurethane from becoming too soft. This improves the strength, hardness, elastic recovery performance, and elastic retention performance of the polyurethane, and improves the heat resistance of the polyurethane.

[0050] (Chain Terminating Agent) When producing polyurethane, a chain terminator having one active hydrogen group can be used as needed for the purpose of controlling the molecular weight of the resulting polyurethane. Examples of these chain terminators include aliphatic monools having one hydroxyl group, such as methanol, ethanol, propanol, butanol, and hexanol, and aliphatic monoamines having one amino group, such as diethylamine, dibutylamine, n-butylamine, monoethanolamine, diethanolamine, and morphopholine. These may be used alone or in combination of two or more. The upper limit of the amount of the chain terminator used is preferably 1,000 ppm by mass or less per 100 parts by mass of the total amount of the polyurethane resin (structural units (A) and (B)).

[0051] <Applications> The polyurethane of the present invention is excellent in heat storage capacity, heat resistance, moldability, shape retention, etc., and is therefore suitable for use as a material for a heat storage material (polyurethane composition for a heat storage material). The polyurethane of the present invention can also be used in electrical appliances, battery packs, and semiconductor products. In particular, it is suitable for use as a battery material for vehicles, lithium battery modules, etc., and for cooling battery packs.

[0052] <Polyurethane Composition for Heat Storage Material> The polyurethane composition for heat storage material used to obtain the heat storage material must contain the polyurethane of the present invention, but may also contain other components. Examples of other components include additives and resins other than the polyurethane of the present invention (hereinafter referred to as "other resins" as appropriate). Specifically, various additives can be added to the polyurethane composition for heat storage material as long as the effects are not impaired. Examples of additives include antioxidants, heat stabilizers, light stabilizers, UV absorbers, fillers, neutralizing agents, lubricants, antifogging agents, antiblocking agents, slip agents, dispersants, colorants, flame retardants, antistatic agents, conductivity-imparting agents, crosslinking agents, crosslinking aids, metal deactivators, molecular weight modifiers, antibacterial agents, antifungal agents, fluorescent brighteners, and light diffusing agents such as organic diffusing agents and inorganic diffusing agents. The antioxidant is not particularly limited as long as it does not impair the effects of the present invention, and examples thereof include phenolic antioxidants and phosphite antioxidants. The addition of an antioxidant can reduce the rate of change in enthalpy before and after heat treatment. Specifically, it is preferable that the rate of change in enthalpy ΔH at the polyurethane-derived peak after heat treatment at 100°C for 200 hours is 10% or less.

[0053] The content of the polyurethane of the present invention in the polyurethane composition for heat storage material is preferably 80% or more and 99.9% or less. By setting the content of the polyurethane of the present invention within the above range, a high enthalpy of fusion can be obtained. The filler is not particularly limited as long as it does not impair the effects of the present invention, and examples include silicon carbide, aluminum nitride, alumina, boron nitride, and silicon nitride. Adding a filler can improve thermal conductivity. Specifically, the content of the filler is preferably 0.1 to 60% by mass, more preferably 0.1 to 50% by mass, and even more preferably 0.1 to 40% by mass, relative to 100% by mass of the polyurethane composition for heat storage material.

[0054] Furthermore, other resins can be blended into the polyurethane composition for heat storage materials as long as the effects are not impaired. Specific examples of other resins include polyethylene, polypropylene, polyester, polyester carbonate, aromatic polycarbonate, polyamide, polyimide, ABS, PMMA, PET, etc. For example, other resins can be blended from the viewpoint of improving shape retention.

[0055] [Heat Storage Material] The heat storage material of the present invention contains the above-mentioned polyurethane.

[0056] <Flame Retardant> The heat storage material of the present invention may further contain a flame retardant. Examples of the flame retardant include at least one flame retardant selected from the group consisting of bromine-based flame retardants, chlorine-based flame retardants, phosphorus-based flame retardants, boron-based flame retardants, silicone-based flame retardants, and nitrogen-containing compounds. The flame retardants may be used alone or in combination of two or more.

[0057] Bromine-based flame retardants suppress combustion by generating bromine gases and blocking oxygen. Examples of bromine-based flame retardants include tetrabromobisphenol A, decabromobiphenyl, and pentabromodiphenyl ether. Chlorine-based flame retardants suppress combustion by generating chlorine gases and blocking oxygen. Examples of chlorine-based flame retardants include chlorine-based paraffin and chlorine-based polyethylene. Phosphorus-based flame retardants block oxygen and heat by forming a carbonized layer. Examples of phosphorus-based flame retardants include phosphate esters and ammonium polyphosphate. Boron-based flame retardants block oxygen and heat by forming a carbonized layer. Examples of boron-based flame retardants include sodium polyborate, borax, and zinc borate. Silicone-based flame retardants form an Si-C inorganic heat insulating layer. Examples of silicone-based flame retardants include silicone resins. Nitrogen-containing compounds block oxygen by generating nitrogen-based gases. Examples of nitrogen-containing compounds include ammonium phosphate, guanidine compounds, and melamine compounds.

[0058] (Phosphorus-Based Flame Retardants) Of the flame retardants described above, phosphorus-based flame retardants are preferred in the present invention from the standpoint of flame retardancy. Examples of phosphorus-based flame retardants include lower phosphates, polyphosphates, melamine-based phosphorus compounds, red phosphorus, condensed phosphate esters, halogen-containing phosphate esters, halogen-containing condensed phosphate esters, and phosphorus compounds represented by the general formula (i) described below. Examples of phosphorus compounds also include trimethyl phosphate, triethyl phosphate, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, cresyl di-2,6-xylenyl phosphate, tris(chloropropyl)phosphate, and tris(tribromoneopentyl)phosphate. The use of these phosphorus compounds as flame retardants provides appropriate fire resistance and fire extinguishing performance. These flame retardants may be used alone or in combination.

[0059] <Lower Phosphates> Lower phosphates refer to salts of inorganic phosphoric acids that are not condensed, i.e., not polymerized, and have one phosphorus atom per molecule of inorganic phosphoric acid. Inorganic phosphoric acids are not limited to phosphoric acid (orthophosphoric acid), but may also include metaphosphoric acid, phosphorous acid, hypophosphorous acid, etc. The phosphate may be any of primary phosphates, secondary phosphates, and tertiary phosphates. Examples of salts include alkali metal salts such as lithium salts, sodium salts, and potassium salts; alkaline earth metal salts such as magnesium salts, calcium salts, strontium salts, and barium salts; salts of metals from Group 3B of the Periodic Table such as aluminum salts; and transition metal salts such as titanium salts, manganese salts, iron salts, nickel salts, copper salts, zinc salts, vanadium salts, chromium salts, molybdenum salts, and tungsten salts. Other examples include ammonium salts and amine salts, such as guanidine salts or salts of triazine-based compounds. Among these, metal salts are preferred, and aluminum salts are more preferred. In this specification, the salt of a melamine compound is defined as a melamine-based phosphorus compound, which will be described later.

[0060] Specific examples of metal salts of lower phosphoric acids include aluminum monophosphate, sodium monophosphate, potassium monophosphate, calcium monophosphate, zinc monophosphate, aluminum diphosphate, sodium diphosphate, potassium diphosphate, calcium diphosphate, zinc diphosphate, aluminum triphosphate, sodium triphosphate, potassium triphosphate, calcium triphosphate, zinc triphosphate, aluminum phosphite, sodium phosphite, potassium phosphite, calcium phosphite, zinc phosphite, aluminum hypophosphite, sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, zinc hypophosphite, aluminum metaphosphate, sodium metaphosphate, potassium metaphosphate, calcium metaphosphate, zinc metaphosphate, etc. Among these, aluminum phosphate and aluminum phosphite are preferred.

[0061] <Polyphosphates> Examples of polyphosphates include ammonium polyphosphates such as ammonium polyphosphate, melamine-modified ammonium polyphosphate, piperazine polyphosphate, and ammonium amide polyphosphate, and metal polyphosphates such as aluminum polyphosphate. Among these, ammonium polyphosphate is preferred from the standpoints of fire resistance, safety, cost, handleability, etc.

[0062] <Melamine-Based Phosphorus Compounds> Examples of melamine-based phosphorus compounds include salts of melamine or melamine derivatives such as melamine, melem, and melon. Examples of salts of melamine or melamine derivatives include melamine polyphosphate, melamine pyrophosphate, melamine orthophosphate, melamine-melam-melem polyphosphate, melamine polymetaphosphate, organic melamine phosphonate, and organic melamine phosphinate. Among these, polyphosphates of melamine-based compounds such as melamine polyphosphate, melamine-melam-melem polyphosphate, and the like are preferred.

[0063] <Condensed Phosphate Ester> The condensed phosphate ester is not particularly limited, but is preferably one or more condensed phosphate esters selected from the group consisting of aromatic condensed phosphate esters, aliphatic condensed phosphate esters, halogen-containing condensed phosphate esters, and halogen-free condensed phosphate esters. It is more preferable to include at least one of an aromatic condensed phosphate ester and a halogen-free condensed phosphate ester. Examples of the condensed phosphate ester include trialkyl polyphosphate, resorcinol polyphenyl phosphate, bisphenol A polycresyl phosphate, resorcinol poly(di-2,6-xylyl)phosphate, hydroquinone poly(2,6-xylyl)phosphate, and condensates thereof. Examples of the halogen-containing condensed phosphate ester include compounds in which the above-mentioned condensed phosphate esters are partially substituted with chlorine atoms. Examples of the halogen-containing phosphate ester include chloroalkyl phosphate esters such as tris(β-chloropropyl)phosphate (TMCPP).

[0064] The compounds represented by general formula (i) are as follows:

[0065] In formula (i), R １ and R ３ may be the same or different and represent hydrogen, a linear or branched alkyl group having 1 to 16 carbon atoms, or an aryl group having 6 to 16 carbon atoms. ２represents a hydroxyl group, a linear or branched alkyl group having 1 to 16 carbon atoms, a linear or branched alkoxyl group having 1 to 16 carbon atoms, an aryl group having 6 to 16 carbon atoms, or an aryloxy group having 6 to 16 carbon atoms. Examples of the compound represented by the above chemical formula (i) include methylphosphonic acid, dimethyl methylphosphonate, diethyl methylphosphonate, ethylphosphonic acid, propylphosphonic acid, butylphosphonic acid, 2-methylpropylphosphonic acid, t-butylphosphonic acid, 2,3-dimethyl-butylphosphonic acid, octylphosphonic acid, phenylphosphonic acid, dioctylphenylphosphonate, dimethylphosphinic acid, methylethylphosphinic acid, methylpropylphosphinic acid, diethylphosphinic acid, dioctylphosphinic acid, phenylphosphinic acid, diethylphenylphosphinic acid, diphenylphosphinic acid, and bis(4-methoxyphenyl)phosphinic acid. The above phosphorus compounds may be used alone or in combination of two or more.

[0066] The upper limit of the melting point of the flame retardant is preferably 200°C or lower, more preferably 180°C or lower, even more preferably 160°C or lower, particularly preferably 140°C or lower, particularly preferably 120°C or lower, and most preferably 100°C or lower. The lower limit of the melting point of the flame retardant is preferably -50°C or higher, more preferably -30°C or higher, even more preferably 0°C or higher, particularly preferably 30°C or higher, particularly preferably 50°C or higher, and most preferably 70°C or higher. Controlling the melting point of the flame retardant can improve dispersibility during the heating process.

[0067] The melting point of the flame retardant (T ｍ，ＦＲ ) and the melting point (T ｍ，ＰＯ ) difference (T ｍ，ＦＲ -T ｍ，ＰＯ The upper limit of the melting point (T) of the flame retardant is preferably 100°C or less, more preferably 80°C or less, even more preferably 60°C or less, and particularly preferably 40°C or less. ｍ，ＦＲ ) and the melting point (T ｍ，ＰＯ ) difference (Tｍ，ＦＲ -T ｍ，ＰＯ The lower limit of the melting point (T) of the flame retardant is preferably −100° C. or higher, more preferably −50° C. or higher, even more preferably 0° C. or higher, and particularly preferably 10° C. or higher. ｍ，ＦＲ ) and the melting point (T ｍ，ＰＯ ) difference (T ｍ，ＦＲ -T ｍ，ＰＯ ) is preferably 0 to 100°C, more preferably 0 to 80°C, even more preferably 0 to 60°C, particularly preferably 0 to 40°C, and particularly preferably 0 to 20°C.

[0068] The melting point of the flame retardant (T ｍ，ＦＲ ) and the melting point (T ｍ，ＰＵ ) difference (T ｍ，ＦＲ -T ｍ，ＰＵ The lower limit of the melting point (T) of the flame retardant is preferably −100° C. or higher, more preferably −50° C. or higher, even more preferably 0° C. or higher, and particularly preferably 10° C. or higher. ｍ，ＦＲ ) and the melting point (T ｍ，ＰＵ ) difference (T ｍ，ＦＲ -T ｍ，ＰＵ ) is preferably 0 to 100°C, more preferably 0 to 80°C, even more preferably 0 to 60°C, particularly preferably 0 to 40°C, and particularly preferably 0 to 20°C.

[0069] (Dispersibility of Flame Retardant) The dispersibility of the flame retardant contained in the heat storage material can be measured by the following method (for example, JP 2007-331966 A). The more uniformly the flame retardant is dispersed in the heat storage material, the more stable the battery's fire spread prevention. In one embodiment, the ratio of the content based on XPS measurement to the content based on XRF measurement of the element corresponding to the flame retardant in the heat storage material measured by the following method is preferably 0.5 to 1.5, more preferably 0.6 to 1.4, even more preferably 0.7 to 1.3, particularly preferably 0.8 to 1.2, and particularly preferably 0.9 to 1.1. (Measurement Method) A test piece measuring 10 mm x 10 mm x 5.0 mm is cut from the heat storage material, and the content of the element corresponding to the flame retardant is measured using an X-ray fluorescence analyzer (XRF) and an X-ray photoelectron spectroscopy (XPS).

[0070] "Elements corresponding to flame retardants" refer to elements inherent in the chemical structure of flame retardants, such as bromine-based flame retardants, chlorine-based flame retardants, phosphorus-based flame retardants, boron-based flame retardants, silicone-based flame retardants, and nitrogen-based compounds. Since the purpose of the measurement is to quantitatively evaluate the dispersibility of the flame retardant, it is preferable to select elements that are only contained in the flame retardant. In this method, the element content on the surface of the cut-out heat storage material is measured by XPS, and the element content inside the cut-out heat storage material is measured by XRF. Therefore, if the ratio between these elements is within the above range, it can be determined that the flame retardant is uniformly dispersed. For XRF, an energy dispersive X-ray fluorescence analyzer EDX-700 manufactured by Shimadzu Corporation can be used.

[0071] In another embodiment, the coefficient of variation of the content of the element corresponding to the flame retardant in the heat storage material, measured by the following method, is preferably 0.15 or less, more preferably 0.13 or less, even more preferably 0.10 or less, particularly preferably 0.08 or less, and particularly preferably 0.05 or less. (Measurement Method) Five test pieces of 10 mm × 10 mm × 5.0 mm are cut out from the heat storage material, and the content of the element corresponding to the flame retardant is measured by an X-ray photoelectron spectroscopy (XPS).

[0072] In this method, the element contents on the surface of the cut-out heat storage material are measured by XPS, and if the coefficients of variation are within the above ranges, it can be evaluated that the flame retardant is uniformly dispersed. Note that XPS can be performed using an X-ray photoelectron spectrometer ESCA-3400 manufactured by Shimadzu Corporation.

[0073] <Adhesive> The heat storage material of the present invention may further contain an adhesive, and the content of the adhesive is preferably 0.001 to 5.0 mass%. By having the content of the adhesive within the above range, heat and cold storage can be performed efficiently. Examples of adhesives include acrylic adhesives, phenolic adhesives, and silane coupling agents, and among these, silane coupling agents are preferred.

[0074] The chemical structure of the silane coupling agent is represented by the following formula (2): X—Si—Y １ Y ２ Y ３ (2) (In formula (2), X is an organic group, and Y １ ~Y ３ are each independently a group capable of forming a bond with an adherend or a precursor group thereof.) The X is not particularly limited as long as it is an organic group, but is preferably a group capable of forming a bond with a partial structure of polyurethane, and is preferably at least one group selected from the group consisting of a vinyl group, an epoxy group, a (meth)acrylic group, an amino group, an isocyanate group, an isocyanurate group, a mercapto group, a polysulfide group, a ureido group, a hydrocarbon group which may have a fluorine atom, a carboxyl group, and a phosphoryl group. １ ~Y ３ (Y １ ~Y ３ are sometimes collectively referred to as Y.) are not particularly limited as long as they are each independently a group capable of forming a bond with the adherend or a precursor group thereof. For example, Si-Y may be a silanol group or a silanol precursor group. Y is preferably at least one group selected from the group consisting of a hydroxy group, an alkoxy group, an acyloxy group, a halogeno group, and a siloxane precursor group, more preferably a hydroxy group or an alkoxy group, and even more preferably an alkoxy group. In addition, Y １ ~Y ３It is preferable that all of the groups are the same. The silane coupling agents can be used alone or in combination of two or more.

[0075] In the heat storage material of the present invention, the ratio of the total equivalent number of isocyanate groups to the total equivalent number of active hydrogen groups contained in the structural unit (A), the structural unit (B), and the adhesive (functional group equivalent ratio) is preferably 0.4 to 1.1. By having such a functional group equivalent ratio within the above range, the heat storage material can have good heat storage properties and shape retention after melting. From the viewpoint of improving this effect, the lower limit is preferably 0.65, more preferably 0.70, and even more preferably 0.80. From the same viewpoint, the upper limit is preferably 1.10, more preferably 1.05, and even more preferably 1.00. The functional group equivalent ratio can be determined by nuclear magnetic resonance (NMR) analysis. Specifically, the active hydrogen group is preferably at least one selected from the group consisting of a hydroxy group, an amino group, a mercapto group, a ureido group, a carboxyl group, and a phosphoryl group, and more preferably a hydroxy group or an amino group.

[0076] The adhesive and the flame retardant can be used in combination. From the viewpoint of facilitating interface control by the adhesive, the heat storage material preferably contains an adhesive and a flame retardant having a melting point of 30° C. or higher. The preferred contents of the adhesive and the flame retardant are the same as the preferred contents of each alone.

[0077] The heat storage material according to one embodiment of the present invention may contain other components in addition to the flame retardant and adhesive. Examples of other components include additives and resins other than the polyurethane according to the present invention (hereinafter, appropriately referred to as "other resins"). Specifically, various additives can be added to the polyurethane for heat storage material as long as the effects are not impaired. Examples of additives include antioxidants, heat stabilizers, light stabilizers, UV absorbers, fillers, neutralizing agents, lubricants, antifogging agents, antiblocking agents, slip agents, dispersants, colorants, antistatic agents, conductivity-imparting agents, crosslinking agents, crosslinking aids, metal deactivators, molecular weight modifiers, antibacterial agents, antifungal agents, fluorescent brighteners, and light diffusing agents such as organic diffusing agents and inorganic diffusing agents.

[0078] <Physical Properties of Heat Storage Material> (Flammability) The heat storage material of the present invention is preferably configured to satisfy the physical properties measured by the following method in accordance with JIS C 60695-11-10 published in 2013. (1) Evaluation by 20 mm vertical combustion test specified in IEC 60695-11-10B, ASTM D3801, and UL94. In one embodiment of the heat storage material of the present invention, the combustion time is preferably 60 seconds or less, more preferably 30 seconds or less, more preferably 20 seconds or less, and more preferably 10 seconds or less. Specifically, a test piece (125 mm x 13 mm x 2.0 mm) made from a sheet prepared using the heat storage material of the present invention is attached vertically to a clamp, and exposed to a 20 mm flame for 10 seconds, and the combustion time is measured. The combustion time is preferably 60 seconds or less, more preferably 30 seconds or less, more preferably 20 seconds or less, and more preferably 10 seconds or less. Furthermore, in the above combustion test, it is preferable that there is no residual flame or afterglow that reaches the designated clamp. Furthermore, in the combustion test based on UL94, it is preferable that the criterion for V-2 is met, more preferably that for V-1, and even more preferably that for V-0 is met. In this judgment, in addition to the flaming combustion time after the first and second flame contacts performed on each of the five test pieces, the total flaming combustion time of the five specimens, the total flaming combustion time and flameless combustion time after the second flame contact, whether combustion reaches the clamp, and whether the cotton ignites.

[0079] (2) Evaluation by horizontal combustion test specified in IEC60695-11-10A method and ASTM D635 One embodiment of the heat storage material of the present invention preferably meets the HB judgment criteria in the combustion test. Specifically, a test piece (125 mm x 13 mm x 1.5 mm) made from a sheet prepared using the heat storage material of the present invention is held horizontally, exposed to a 20 mm flame for 30 seconds, and the burning rate at a 75 mm mark distance is measured. The burning rate is preferably 100 mm / min or less, more preferably 85 mm / min or less, more preferably 75 mm / min or less, more preferably 65 mm / min or less, and more preferably 55 mm / min or less.

[0080] (3) Evaluation by horizontal combustion test specified in IEC 60695-11-10A method and ASTM D635 One embodiment of the heat storage material of the present invention preferably meets the HB judgment criteria in the combustion test. Specifically, a test piece (125 mm x 13 mm x 3.0 mm) made from a sheet prepared using the heat storage material of the present invention is held horizontally, exposed to a 20 mm flame for 30 seconds, and the burning rate at a distance of 75 mm between the marks is measured. The burning rate is preferably 60 mm / min or less, more preferably 50 mm / min or less, more preferably 40 mm / min or less, and more preferably 30 mm / min or less.

[0081] (Tensile shear bond strength) The heat storage material of the present invention preferably has a tensile shear bond strength of 0.40 MPa or more, measured in accordance with Japanese Industrial Standard JIS K 6850:1999 "Test method for tensile shear bond strength between adhesive and rigid adherend" at a tensile speed of 5 mm / min. When the heat storage material satisfies these physical properties, it is possible to provide a heat storage material capable of fixing a heating element.

[0082] Specifically, the tensile shear adhesive strength is measured by the following procedure. First, two adherend test pieces measuring 25 mm x 100 mm x 1.6 mm are prepared. Next, a heat storage material is applied to the overlapping portions of the adherend test pieces so that the overlap length of the adherend test pieces is 12.5 mm and the thickness of the heat storage material is 0.2 mm, and then cured. Then, an area 50 mm or more away from the edge of the overlapping portion of each adherend test piece is fixed as a gripping portion, and the test is performed at a tensile speed of 5 mm / min to obtain a tensile shear load value in N. The obtained tensile shear load value is expressed as a function of the adhesive area (mm ２ The tensile shear bond strength can be converted into MPa units by dividing the tensile shear load by the tensile shear load. The tensile shear load value can be measured using a precision universal testing machine (such as the Autograph AG-X manufactured by Shimadzu Corporation). The curing conditions can be either a condition of holding at 23°C for 7 days or a condition of heating at 120°C for 30 minutes.

[0083] The lower limit of the tensile shear bond strength of the heat storage material of the present invention is 0.40 MPa or more, preferably 0.60 MPa or more, more preferably 0.80 MPa or more, even more preferably 1.0 MPa or more, even more preferably 1.5 MPa or more, and most preferably 2.0 MPa or more. The upper limit of the tensile shear bond strength is not particularly limited, but from the viewpoint of recycling, it is preferably 10 MPa or less.

[0084] (Evaluation of Thermal Properties) The thermal properties of the heat storage material of the present invention can be measured by the following method. (1) Measurement Conditions and Apparatus A sample of 2 to 10 mg is collected from the heat storage material and sealed in an aluminum pan for measurement. The measurement atmosphere is nitrogen, and the temperature is increased from 25°C to 80°C at a heating rate of 1°C / min, held for 1 minute, and then cooled from 80°C to 25°C at a heating rate of 1°C / min. Thereafter, the temperature is again increased from 25°C to 80°C at a heating rate of 1°C / min, held for 1 minute, and cooled to -10°C at a heating rate of 1°C / min and held for 1 minute. A differential scanning calorimeter (e.g., Q2000 model manufactured by TA Instruments) can be used for the measurement. (2) Measurement Items In the DSC measurement of the present invention, the following thermal properties are obtained: Melting point (Tm): the maximum point of the endothermic peak during the temperature rise process Melting enthalpy (ΔH): calculated in J / g by dividing the heat quantity corresponding to the area under the endothermic peak in the DSC curve by the mass of the sample.

[0085] The heat storage material according to the present invention preferably has a melting point of 20 to 80°C. The lower limit of the melting point is more preferably 20°C, even more preferably 30°C, even more preferably 40°C, and particularly preferably 45°C. The upper limit is more preferably 70°C, even more preferably 60°C. By having a melting point within the above range, heat and cold storage can be performed efficiently. Furthermore, when the heat storage material according to the present invention is used for a battery, the battery can efficiently absorb heat.

[0086] In the heat storage material according to the present invention, the fusion enthalpy in the range of 20 ° C. or higher and 80 ° C. or lower, as observed by differential scanning calorimetry, is preferably 20 J / g or higher. When the fusion enthalpy is 20 J / g or higher, it can be suitably used as a heat storage material. From the above viewpoint, the fusion enthalpy in the range of 20 ° C. or higher and 80 ° C. or lower is more preferably 30 J / g or higher, and even more preferably 35 J / g or higher. The upper limit is not particularly limited, and may be, for example, 500 J / g or lower.

[0087] <Method for producing a heat storage material> A method for producing a heat storage material according to one embodiment of the present invention comprises curing a composition containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and an adhesive, wherein the ratio of the total equivalents of isocyanate groups to the total equivalents of active hydrogen groups contained in the aromatic polyisocyanate compound having an average functionality of 2.1 or more, the polyalkylene ether glycol, and the adhesive is adjusted to 0.4 to 1.1. The aromatic polyisocyanate compound, the polyalkylene ether glycol, and the adhesive are as described above.

[0088] The adhesive preferably contains a silane coupling agent represented by formula (2): X—Si—Y １ Y ２ Y ３ (2) (In formula (2), X is an organic group, and Y １ ~Y ３ are each independently a group capable of forming a bond with an adherend or a precursor group thereof.

[0089] <Uses> The heat storage material of the present invention is excellent in heat storage properties, heat resistance, moldability, shape retention, etc., and is therefore suitable for use as a heat storage material. The heat storage material of the present invention can also be used in electrical appliances, assembled batteries, and semiconductor products. In particular, it is suitable for use as a battery material for vehicles, lithium battery modules, etc., and is suitable for cooling assembled batteries.

[0090] A preferred embodiment of the heat storage material of the present invention is a heat storage material containing polyurethane and a flame retardant, wherein the polyurethane contains structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyalkylene ether glycol, and the burning time of a test piece measured by the following measurement method is 60 seconds or less. Such a heat storage material can achieve both heat absorption and flame retardancy. <Measurement method> A test piece (125 mm x 13 mm x 2.0 mm) is attached vertically to a clamp and exposed to a 20 mm flame for 10 seconds, and the burning time is measured.

[0091] Another preferred embodiment of the heat storage material of the present invention is a heat storage material containing polyurethane, wherein the polyurethane contains a structural unit (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and a structural unit (B) derived from a polyalkylene ether glycol, and the tensile shear adhesive strength measured by the following measurement method is 0.40 MPa or more. Such a heat storage material can fix a heating element. (Measurement method) Two adherend test pieces measuring 25 mm x 100 mm x 1.6 mm were prepared, and the heat storage material was applied to the overlapping portions of the adherend test pieces so that the overlapping length of the adherend test pieces was 12.5 mm and the thickness of the heat storage material was 0.2 mm, and the heat storage material was cured. An area 50 mm or more away from the edge of the overlapping portion of each adherend test piece was fixed as a gripping portion, and the tensile shear load value obtained by testing at a tensile speed of 5 mm / min was measured. The tensile shear load value was measured based on the adhesive area (mm ２ ) to obtain the tensile shear bond strength value.

[0092] [Composition] The composition of the present invention contains an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and a flame retardant and / or adhesive. The isocyanate index of the composition containing the aromatic polyisocyanate compound having an average functionality of 2.1 or more, the polyalkylene ether glycol, and the flame retardant is preferably 0.4≦(II) / (I)≦1.1. The ratio of the total number of equivalents of isocyanate groups to the total number of equivalents of active hydrogen groups contained in the aromatic polyisocyanate compound having an average functionality of 2.1 or more, the polyalkylene ether glycol, and the adhesive is preferably 0.4 to 1.1. The mass fraction of the polyalkylene ether glycol is preferably 50% by mass or more and 99% by mass or less relative to the total mass of the aromatic polyisocyanate compound having an average functionality of 2.1 or more and the polyalkylene ether glycol. The aromatic polyisocyanate compound, polyalkylene ether glycol, flame retardant, and adhesive are as described above.

[0093] The adhesive preferably contains a silane coupling agent represented by formula (2): X—Si—Y １ Y ２ Y ３ (2) (In formula (2), X is an organic group, and Y １ ~Y ３ are each independently a group capable of forming a bond with an adherend or a precursor group thereof.) Specifically, the active hydrogen group is preferably at least one selected from the group consisting of a hydroxy group, an amino group, a mercapto group, a ureido group, a carboxyl group, and a phosphoryl group, and more preferably a hydroxy group or an amino group.

[0094] The composition of the present invention can be prepared by mixing an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and an adhesive contained in the composition so as to achieve a predetermined functional group equivalent ratio. By ensuring that the functional group equivalent ratio is within the above range, a heat storage material can be obtained that exhibits good heat storage properties and shape retention after melting. From the viewpoint of improving this effect, the lower limit is preferably 0.65, more preferably 0.70, and even more preferably 0.80. From the same viewpoint, the upper limit is preferably 1.10, more preferably 1.05, and even more preferably 1.00. The functional group equivalent ratio can be determined by nuclear magnetic resonance (NMR) analysis.

[0095] The catalyst (c) used to produce the polyurethane of the present invention is preferably an organic catalyst, such as an amine or an imidazole. When an aromatic polyisocyanate compound is used, the use of an organic catalyst can improve the activity of the urethanization reaction, thereby enabling control of the curing time and productivity during production. Examples of organic catalysts that can be used include base catalysts (basic compounds) such as amine catalysts (e.g., triethylenediamine, triethylamine, N-ethylmorpholine), imidazole catalysts (e.g., 1,2-dimethylimidazole), and acid catalysts (e.g., acetic acid, phosphoric acid, sulfuric acid, hydrochloric acid, sulfonic acid). Among these, base catalysts are preferred, and nitrogen-containing compounds are more preferred. It is more preferred to include at least one of an amine catalyst and an imidazole catalyst, and it is preferred to include at least one of triethylenediamine and imidazole. The catalyst may be used alone or in combination of two or more types. From the perspective of controlling the curing time, it is preferable to include two or more organic catalysts. The amount of the catalyst added is preferably 10 ppm to 1000 ppm based on 100 parts by weight of the total solids content in the composition for producing the polyurethane of the present invention (details will be described later). By setting the amount of catalyst added within this range, polyurethane can be produced efficiently.

[0096] <Flame Retardant> The flame retardant in the composition of the present invention can be any of the flame retardants described above. From the viewpoint of imparting flame retardancy, it is preferable to uniformly disperse the flame retardant in the heat storage material. Other methods for imparting flame retardancy include, for example, a chemical method in which a chemical structure that is likely to exhibit flame retardancy is introduced into the chemical structure of polyurethane. Physical methods include a method of designing the particle structure of the flame retardant and a method of improving the mixing process of the flame retardant.

[0097] (Improvement of dispersibility by coating or surface treatment) The surface of the flame retardant particles is coated with TiO ２ One possible method is to coat the surface of the polymer with a material such as titanium dioxide or melamine resin to introduce hydrophilic groups and reduce the interfacial energy with the polyalkylene ether glycol. The coating layer acts by forming hydrogen bonds with the OH groups of the PEG while suppressing moisture absorption and phosphoric acid generation. This method is advantageous in terms of suppressing aggregation, improving moisture resistance, and reducing coloration. For example, US Pat. No. 5,026,757 discloses a method using TiO ２ It is disclosed that red phosphorus is stabilized by a double coating of red phosphorus and resin, thereby improving compatibility with the resin.

[0098] (Improving Dispersibility by Nanoparticle Formation) One possible nanoparticle formation technique involves using a ball mill or sand mill to reduce flame retardant particles to 100 nm or less and simultaneously adsorbing a hydrophobic modifier. As the particle size decreases, Brownian motion becomes dominant, allowing the flame retardant to diffuse uniformly in the polyalkylene ether glycol without settling. This method is advantageous in that even with a small amount of addition, the flame retardant efficiency is improved due to the high specific surface area effect. For example, CN111138717 discloses a manufacturing method for producing nano-sized coated red phosphorus using a ball mill / sand mill in the presence of a hydrophobic surface modifier, thereby improving dispersibility and safety.

[0099] (Improving Dispersibility Through Blending Technology) One possible method is to masterbatch a flame retardant at a high concentration into a liquid polymer, such as castor oil or a polyol, that is compatible with polyalkylene ether glycol, and then blend this into a polyalkylene ether glycol composition. The liquid carrier acts by reducing interfacial tension. This method is advantageous in terms of dust suppression and shortening mixing time. For example, WO 2017 / 029337 discloses that dispersibility and flame retardancy can be simultaneously imparted by using a polymer-polyol dispersion in which olamine having a phosphate ester group is reacted in a base polyol.

[0100] (Improving Dispersibility Through Physical Dispersion Processes, Such as Ultrasonic and High-Shear Mixing) One possible method is to disperse a flame retardant in polyalkylene ether glycol while finely pulverizing it using ultrasonic homogenization or a rotor-stator high-shear mixer. This works by using cavitation shock waves or strong shear stress to break down agglomerates, and then rewetting the particle surfaces with polyalkylene ether glycol. This method is advantageous in that it does not require chemical modification and can achieve a uniform submicron dispersion in a short period of time. For example, US Pat. No. 4,623,583 discloses the use of a high-shear mixer to obtain a stabilized dispersion of flame retardant with an average particle size of 5 μm or less.

[0101] [Two-component curing composition] The two-component curing composition of the present invention comprises a composition (a) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more and a polyol composition (b) containing a polyalkylene ether glycol. The aromatic isocyanate compound and the polyalkylene ether glycol are as described above.

[0102] By forming the composition of the present invention into a two-component curing composition, storage stability can be improved. Specifically, the mass ratio of the polyol composition (b) to the composition (a) containing an aromatic isocyanate compound is preferably 0.9 to 1.1, more preferably 0.95 to 1.05. Thus, by setting the mass ratio of the composition (a) to the composition (b) to 1 or close to 1, preparation of a mixture of the composition (a) and the composition (b) becomes easier. The flame retardant is preferably contained in the composition (b). If the adhesive has an isocyanate group, it is preferably contained in the composition (a), and if it does not have an isocyanate group, it is preferably contained in the composition (b). When a catalyst (c) is used, the polyol composition (b) containing the polyalkylene ether glycol preferably contains the catalyst. By including a catalyst in the composition (b), the aromatic polyisocyanate compound and the polyalkylene ether glycol have excellent storage stability before mixing, and after mixing, the reaction is accelerated, allowing them to cure rapidly, resulting in various good physical properties of the cured product obtained by curing.

[0103] [Composition Kit] The composition kit of the present invention comprises a first container filled with an isocyanate composition (a) (sometimes simply referred to as composition (a)) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a second container filled with a polyol composition (b) (sometimes simply referred to as composition (b)) containing a polyalkylene ether glycol, and the isocyanate composition (a) or the polyol composition (b). The aromatic polyisocyanate compound and the polyalkylene ether glycol are as described above. Examples of containers include syringes, cartridges, SUS cans, pails, and drums. The composition kit can suppress the settling of fillers, additives, and the like contained in compositions (a) and (b) while the compositions (a) and (b) are stored in the containers. From the viewpoint of productivity, the ratio of the volume of the second container to the volume of the first container is preferably 5 to 15, more preferably 6 to 14, and even more preferably 7 to 13.

[0104] [Supply Form] The present invention can also provide a supply form of the two-component curing thermally conductive material comprising a first container filled with the above-described composition (a) and a second container filled with the above-described composition (b). As described above, examples of the container include a syringe, a cartridge, a pail, and a drum. This supply form also provides excellent workability when removing the compositions (a) and (b) by discharging or the like. From the viewpoint of productivity, the ratio of the volume of the second container to the volume of the first container is preferably 5 to 15, more preferably 6 to 14, and even more preferably 7 to 13.

[0105] [Heat storage molding] The heat storage molding of the present invention is a molding of the above-mentioned heat storage material (sometimes referred to as a "support structure having heat absorption properties" or simply as a "support structure"). The density of the heat storage molding (support structure) is 1.0 to 2.5 g / cm3 from the viewpoint of increasing thermal conductivity. ３ is preferably 1.0 to 2.0 g / cm ３ In addition, from the viewpoint of improving heat storage performance, the thermal conductivity of the heat storage molded body is preferably 0.2 to 5.0 W / (m K), more preferably 1.0 to 5.0 W / (m K), and even more preferably 1.0 to 3.0 W / (m K).

[0106] The heat storage molded body is made of a heat storage material and is obtained, for example, by molding the heat storage material. Specifically, it is produced by molding the heat storage material into various shapes such as a sheet, plate, granules, pellets, or tube. Common molding methods are used for molding, specifically extrusion molding and injection molding (e.g., insert molding, two-color molding, sandwich molding, gas injection molding, etc.). More specifically, the components are mixed and melted during the production of the heat storage material, and the mixture can be poured into a mold as is (e.g., at the molten temperature) or slightly cooled and then molded. Furthermore, since the heat storage material solidifies at a temperature lower than its flow initiation temperature, it can be molded into a block shape and then cut into a sheet or plate shape. Furthermore, the heat storage material can be attached, coated, or impregnated onto a film, cloth, fiber, particle board, or the like to produce a sheet or plate shape. Alternatively, the heat storage material can be packed in a polyethylene bag or the like and cooled to produce a sheet, plate, or rod shape. Alternatively, the material may be extruded into a sheet or plate using an extruder. The material may be extruded into a rod or pipe shape and then cut into granules or pellets. In each of the extrusion methods, the apparatus and processing conditions are not particularly limited.

[0107] The shape of the heat storage molded body is not particularly limited, and examples thereof include a sheet, film, plate, particulate, lump, fiber, rod, porous body, foam, etc., with a sheet, film, or plate being preferred. Furthermore, the heat storage molded body may be subjected to a surface treatment such as corona discharge treatment, flame treatment, plasma treatment, or ozone treatment, which is commonly used industrially. When using the heat storage molded body as a support structure for unit cells included in a battery pack, the support structure is usually manufactured by filling the spaces between multiple unit cells with the above-mentioned composition and curing it, but a support structure including recesses and / or hollows into which the unit cells can be attached may also be manufactured in advance.

[0108] <Uses of heat storage molded bodies> The uses of the heat storage molded bodies are not particularly limited, but because they have excellent heat storage performance, heat resistance, moldability, and shape retention, they are suitably used, for example, as products or components thereof that directly or indirectly require heat or cold insulation performance.

[0109] Examples of products or components thereof that directly or indirectly require heat or cold insulation performance include building materials, furniture, interior goods, bedding, bathroom materials, vehicles, air conditioning equipment, electrical appliances, thermal containers, food packaging films, clothing, daily necessities, agricultural materials, fermentation systems, thermoelectric conversion systems, heat transfer media, electronic devices, heat pumps, and lithium battery modules. Among these, the material is suitable for use as a building material, specifically as a heat storage building material installed around pipes for delivering heat sources for underfloor heating or central heating, or for keeping heat sources warm in planar heating devices such as electric blankets. Furthermore, among these, the material is particularly suitable for use as a battery material for vehicles and lithium battery modules, and for cooling battery packs, as described in detail below. In the present invention, the heat source is not limited as long as it generates heat, and examples include heat transfer media such as water, oil, and gas, and electric heating wires.

[0110] Furthermore, because the heat storage molding can maintain a solid state above the endothermic peak, it can be molded into the shape of a building material. Once solidified, it does not return to a liquid state, so it can be incorporated into porous materials or poured around a heat source for solidification. Furthermore, because the heat storage molding can be molded without solvents, it can be poured directly into equipment or modules for solidification. Furthermore, because the heat storage material reduces damage to equipment and modules due to temperature changes, it can contribute to extending the life of the equipment and modules.

[0111] [Battery Pack] The battery pack is applied to battery packs mounted in, for example, electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), electric heavy machinery, electric motorcycles, electrically assisted bicycles, ships, aircraft, trains, uninterruptible power supplies (UPSs), home energy storage systems, storage battery systems for stabilizing power systems that utilize renewable energy sources such as wind power, solar power, tidal power, and geothermal power. However, the battery pack can also be used as a power source that supplies power to devices other than the above-mentioned EVs.

[0112] One embodiment of the present disclosure is a battery pack including a plurality of unit cells and a support structure having a heat absorption mechanism. The support structure is formed from a heat storage material containing the polyurethane of the present invention. The battery pack formed using the plurality of unit cells includes the support structure and the plurality of unit cells attached to the support structure.

[0113] From the viewpoint of cooling the unit cells, it is preferable that the heat storage molding contains a thermosetting polyurethane and that the melting temperature of the heat storage molding is 20 to 80°C. From the viewpoint of efficiently cooling the unit cells, it is preferable that the heat storage molding has a single endothermic peak temperature. From the viewpoint of efficiently cooling the unit cells, it is preferable that the distance between any two adjacent unit cells is 1.0 mm or more, more preferably 1.5 mm or more, even more preferably 2.0 mm or more, and even more preferably 2.5 mm or more. Furthermore, it is more preferable that it is 1.0 to 10 mm, and even more preferably 2.0 to 5.0 mm. The distance between the unit cells means the closest distance between the two adjacent batteries.

[0114] The support structure preferably includes a plurality of recesses and / or hollows. The recesses and hollows may be hollows that are not open to any end face, recesses that have an opening on the same plane as one end face, or recesses that have openings on the same plane as two or more end faces. From the viewpoint of facilitating attachment of the unit cells, the support structure preferably includes a plurality of recesses, and more preferably the recesses have an opening on the same plane as at least one end face.

[0115] From the viewpoint of efficiently cooling the unit cells, the center-to-center distance between the two closest open surfaces on the same plane and / or the center-to-center distance between the hollow portions is preferably 1.0 cm or more, more preferably 1.5 cm or more, more preferably 2.0 cm or more, and even more preferably 2.5 cm or more, more preferably 1.0 to 10 cm, and even more preferably 2.0 to 5.0 cm.

[0116] From the viewpoint of efficiently cooling the unit cells, it is preferable that the recesses and / or hollows of the support structure surround the unit cells. When the surface area of ​​the unit cells is taken as 100%, the lower limit of the proportion of the surface area of ​​the unit cells that contacts the recesses and / or hollows of the support structure is usually 10% or more, preferably 25% or more, more preferably 50% or more, and even more preferably 75% or more. The larger the contact area between the support structure and the unit cells, the more easily the unit cells are fixed and cooled efficiently. Furthermore, the upper limit of the proportion of the area in contact with the unit cell surface is usually 100% or less, preferably 95% or less.

[0117] A detailed description will be given of the case where the unit cell is a cylindrical battery. From the viewpoint of efficiently cooling the unit cell, it is preferable that the support structure contacts the outer peripheral surface of the cylindrical battery over 360°. That is, it is preferable that the recessed and / or hollow portion included in the support structure has a cylindrical shape corresponding to the cylindrical battery. When the support structure includes multiple recessed portions having openings on the same plane as at least one end face, it is preferable that the openings have a circular shape. The diameter of the circle of the openings is not particularly limited as long as it can contact the outer peripheral surface of the cylindrical battery, but is preferably 10 to 50 mm, more preferably 25 to 50 mm.

[0118] As one embodiment of the present invention, a case in which a support structure includes a plurality of recesses is shown in Fig. 1. A plurality of recesses 200 having openings on the same plane on one end surface of a support structure 610 surround a cylindrical battery (single cell) 400, and the distance between the two closest recesses is the center-to-center distance L between the opening surfaces of the recesses. １ The distance between two adjacent cylindrical batteries (single cells) 400 is the distance L ２ As another embodiment, a case where the support structure includes a plurality of hollow bodies is shown in FIG. 2. A plurality of hollow sections 300 having no openings on any end face of the support structure 610 surround the cylindrical battery (cell) 400, and the distance between the two closest hollow sections is the center-to-center distance L ３ The distance between two adjacent cylindrical batteries (single cells) 400 is the distance L ２ is.

[0119] <Single Cell> An example of a single cell is a rectangular parallelepiped having height, width, and thickness directions, with terminals provided on its upper surface. The single cell is, for example, a lithium-ion secondary battery equipped with a positive electrode and a negative electrode capable of absorbing and releasing lithium ions, and an electrolyte. In addition to lithium-ion secondary batteries, secondary batteries such as all-solid-state lithium-ion batteries, nickel-metal hydride batteries, nickel-cadmium batteries, and lead-acid batteries can also be used. Examples of the single cell include prismatic batteries, pouch-type batteries, and cylindrical batteries. To achieve a cooling effect, the single cell and the heat storage molding need only be in contact with each other at least partially, and the heat storage molding may be in contact with the single cell via a packaging material covering the heat storage molding. Among the above-mentioned single cells, cylindrical batteries are preferred due to their ease of handling. The shape of the heat storage molding can be appropriately designed to match the single cell.

[0120] [Battery Pack] One embodiment of the present invention is a battery pack including a battery assembly and a housing. That is, the battery pack is one in which the battery assembly is housed in the housing. The housing has a bottom plate and side plates extending along the outer periphery of the bottom plate. The number of cells can be selected as appropriate, and the positive and negative terminals of adjacent (opposing) cells are electrically connected in series by a bus bar via the support structure, thereby allowing the battery assembly to output a predetermined power. From the viewpoint of efficiently cooling the cells, it is preferable that the heat storage molding body has a continuous structure within the housing. That is, when the heat storage molding body is used as the support structure, it is preferable that the support structure be an integrally molded product. From the viewpoint of efficiently cooling the cells, it is preferable that the support structure be in contact with the inner wall of the housing and the cells.

[0121] In one embodiment of the battery pack, a heat transfer plate is disposed between the upper surface of the bottom plate of the housing and each of the cells (prismatic cells). From the viewpoint of efficiently cooling the cells, it is preferable that the heat transfer plate contacts the cells and the support structure, and it is more preferable that the heat transfer plate is disposed at the bottom of the heat storage material. In other words, it is more preferable that the support structure contacts the inner wall of the housing, the cells, and the heat transfer plate.

[0122] <Method for Manufacturing a Battery Pack> A method for manufacturing a battery pack according to one embodiment of the present invention involves filling a housing containing a plurality of unit cells (cylindrical batteries) with a two-component curing composition as a potting material through a nozzle. The potting material is a two-component curing composition containing a polyalkylene ether glycol and an aromatic polyisocyanate compound having an average functionality of 2.1 or more before heating (before the curing reaction), and becomes polyurethane after heating (after the curing reaction). The polyurethane may be a heat storage material further containing an antioxidant and a filler, or may be a heat storage molded body filled into a housing of a specific shape. A preferred embodiment of the battery pack manufacturing method involves filling a housing containing a plurality of unit cells with a composition containing an aromatic compound having an average functionality of 2.1 or more isocyanate groups, a polyalkylene ether glycol, a flame retardant, and a catalyst. From the perspective of efficient filling, the method preferably includes at least one of the following steps: (1) heating the composition to or above the melting point of the polyalkylene ether glycol, (2) heating the housing, and (3) heating the unit cells. In the steps (1) to (3), heating is preferably performed at a temperature above the melting point of the polyalkylene ether glycol, more preferably at 20 to 120°C, even more preferably at 40 to 120°C, and even more preferably at 60 to 120°C. The composition is filled using a nozzle. From the viewpoint of efficient filling, it is preferable to fill the composition from at least two locations. At least two nozzles for filling the composition may be provided, or one nozzle may be moved to fill from multiple locations, or a combination of these may be used. In the example shown in FIG. 3 , a housing 500 in which multiple cylindrical batteries 400 are arranged is filled with the composition 600 using a nozzle 800, thereby producing an assembled battery including multiple cylindrical batteries 400 and a support structure 610, and a battery pack 700 including the housing 500.

[0123] The variables in the potting process, namely, cell-to-cell distance, viscosity of the potting material, and flow rate, control the fill time. Small cell-to-cell distance, high viscosity of the potting material, and high flow rate reduce manufacturing efficiency.

[0124] From the viewpoint of enhancing cooling efficiency, the composition is preferably filled to 50% or more, more preferably 60% or more, more preferably 70% or more, and more preferably 80% of the height of the battery (100%), and is preferably filled to 100% or less, more preferably 97% or less, more preferably 95% or less, more preferably 90% or less, and more preferably 85% or less. From the viewpoint of efficient filling, the viscosity (Pa s) of the composition at the time of filling, the filling volume flow rate (m ３ It is preferable to adjust F in formula (I), which is defined by the viscosity of the composition ( / s) and the minimum distance (m) between the batteries arranged in the housing, to 1.5 N or less. F = (viscosity of the composition) ０．５３ × (filling volume flow rate) ０．６２ / (minimum distance between multiple batteries placed inside the housing) １．３ ... (I)

[0125] From the viewpoint of efficiently cooling the cells, the method of using the battery pack preferably includes raising the temperature to an endothermic temperature and cooling at 100° C. / min or less, more preferably 75° C. / min or less, even more preferably 50° C. / min or less, still more preferably 25° C. / min or less, particularly preferably 10° C. / min or less, even more preferably 5° C. / min or less, and particularly preferably 1° C. / min or less. Preferably, the method includes maintaining the temperature at or above the endothermic temperature for 1 minute or more.

[0126] The present invention will be described in more detail below using examples and comparative examples, but the present invention is not limited to the following examples and comparative examples as long as it does not deviate from the gist of the present invention.

[0127] [Evaluation Method] <Measurement Method by Differential Scanning Calorimetry> (Melting Point (Melting Temperature)) An aluminum pan containing about 5 mg of sample was heated under a nitrogen atmosphere from 25°C to 90°C at a heating rate of 5°C / min. The pan was then cooled to -20°C at a heating rate of 1°C / min. Thereafter, the pan was heated again to 90°C at a heating rate of 1°C / min. The endothermic peak temperature (melting point) was determined from the DSC data (DSC curve) obtained from the second heating. Specifically, the maximum point of the endothermic curve in the range of 20°C to 80°C was determined, and the temperature at this maximum point was taken as the melting point (melting temperature).

[0128] (Crystallization Temperature (Solidification Temperature)) An aluminum pan containing about 5 mg of sample was heated under a nitrogen atmosphere from 25°C to 90°C at a temperature increase rate of 5°C / min. The pan was then cooled to -20°C at a temperature decrease rate of 1°C / min. Thereafter, the pan was heated again to 90°C at a temperature increase rate of 1°C / min. The exothermic peak temperature (crystallization temperature) was determined from the DSC data (DSC curve) obtained during this temperature decrease. Specifically, the maximum point of the exothermic curve in the range of -10°C to 60°C was determined, and the temperature at this maximum point was taken as the crystallization temperature (solidification temperature).

[0129] (Melting enthalpy ΔH) DSC data (DSC curve) was obtained by the same method as in the endothermic peak temperature measurement. This DSC data was used as the measurement curve. A straight line was drawn between the measurement point at 20°C and the measurement point at 80°C on the measurement curve. The total amount on the endothermic side of this line was used as the melting enthalpy. The total amount is expressed as the area of ​​the region surrounded by the straight line and the DSC curve. If there was no peak in the measurement curve between 20°C and 80°C, the melting enthalpy was considered to be 0.

[0130] <Polyol Ratio (PEG Ratio)> This is the content ratio (mass ratio) of structural units derived from polyol in polyurethane.

[0131] <Bleed-out evaluation> The sheets produced in each example were stored in a natural convection dryer set at 200°C for 4 hours (240 minutes), and then the sheets were visually inspected and evaluated according to the following evaluation criteria: (Evaluation criteria) 1: No change 2: No liquid visible, but glossy surface 3: Liquid visible on the surface 4: Liquefied and solid areas mixed (between evaluations 3 and 5) 5: Completely liquefied

[0132] <Phase state at 80°C> If the heat storage material is kept at a temperature higher than the endothermic peak temperature and liquefies, it may leak out and cause a loss of heat storage function. Therefore, the phase state after melting was evaluated. The sheet was cut into 30 x 30 mm pieces to be used as test samples, which were placed on a hot plate at 80°C and covered with a glass petri dish. After holding for 15 minutes, the test sample was checked for fluidity when touched with a spatula, and the phase state was evaluated according to the following criteria. Evaluation criteria Solid: No fluidity, can maintain shape. Liquid: Fluidity exists and cannot maintain shape.

[0133] [Experimental Example 1] <Example 1-1> Polycarbonate diol 1 (molecular weight 2000, hydroxyl value 56 mgKOH / g, viscosity 650 to 1300 mPa·s, melting point 50 to 60°C, bio content 92, R of structural unit (B)) heated to 65°C was placed in a disposable cup. １ 100 g of 1,10-decanediol (n: 9.9), a hydrocarbon having 10 carbon atoms, was weighed out. 0.05 g of a urethanization catalyst solution prepared by weighing triethylenediamine and polypropylene glycol in a 1:9 ratio, dissolving them at 80°C, and returning them to room temperature was added and mixed. The mixture was then thoroughly mixed using a three-one motor. 11.6 g of polymethylene polyphenyl polyisocyanate (p-MDI) (average functionality 2.8) was added and allowed to react for 1 minute while stirring using a three-one motor. A silicone release film was then placed on a glass plate, and the resulting mixture was poured into a 2 mm thick mold made with a silicone release film. The mixture was cured for 30 minutes and aged at room temperature for 1 week, yielding a 2 mm thick sheet. The evaluation results are shown in Table 2.

[0134] (Evaluation of Heat Resistance) The produced sheet was cut into a size of 1 cm x 1 cm and stored for 4 hours in a natural convection dryer set at 200° C. Evaluation was carried out by differential scanning calorimetry before and after storage.

[0135] Examples 1-2 to 1-4 Sheets having a thickness of 2 mm were obtained in the same manner as in Example 1-1, except that the amount of p-MDI added was changed as shown in Table 1. The evaluation results are shown in Table 2.

[0136] <Example 1-5> As the polycarbonate polyol, polycarbonate polyol 2 (molecular weight 3000, hydroxyl value 37 mgKOH / g, viscosity 5000 to 7000 mPa·s, melting point 52°C, R of structural unit (B) １ A sheet having a thickness of 2 mm was obtained in the same manner as in Example 1-1, except that a 1,6-hexanediol (a hydrocarbon having 6 carbon atoms, n: 22.5) was used and the blending amounts of each component were changed as shown in Table 1. The evaluation results are shown in Table 2.

[0137] <Example 1-6> As the polycarbonate polyol, polycarbonate polyol 3 (molecular weight 3000, hydroxyl value 37 mgKOH / g, viscosity 2000 to 4000 mPa·s, melting point 50 to 60°C, R of structural unit (B) １ A sheet having a thickness of 2 mm was obtained in the same manner as in Example 1-1, except that a 1,10-decanediol (n: 15.4, a hydrocarbon having 10 carbon atoms) was used and the blending amounts of each component were changed as shown in Table 1. The evaluation results are shown in Table 2.

[0138] Comparative Example 1 A sheet having a thickness of 2 mm was obtained in the same manner as in Example 1-1, except that polytetramethylene ether glycol (PTMG4000) manufactured by Mitsubishi Chemical Corporation and 1,4-butanediol as a chain extender were used instead of polycarbonate polyol, and the blending amounts of each component were changed as shown in Table 1. The evaluation results are shown in Table 2.

[0139]

[0140]

[0141] The results shown in Table 2 indicate that in Comparative Example 1-1, which used PTMG as the polyol, the bleed-out evaluation after 4 hours at 200°C showed a mixture of liquefied and solid areas, indicating that the polyol component had partially liquefied and was therefore unsuitable for use at high temperatures and could not be used repeatedly. In contrast, the polyurethanes of the present invention in Examples 1-1 to 1-6 did not liquefy the polyol, and maintained their crystallization and melting temperatures even after 4 hours of heat treatment at 200°C, and also showed good results in the bleed-out evaluation.

[0142] Experimental Example 2 Example 2-1 100 g of polyalkylene ether glycol (B-1) heated to 65°C was weighed into a disposable cup. Separately, triethylenediamine manufactured by Tokyo Chemical Industry Co., Ltd. and Sannix PP-2000, a polypropylene glycol manufactured by Sanyo Chemical Industries, Ltd., were weighed in a ratio of 1:9 as a urethanization catalyst, dissolved at 80°C, and returned to room temperature. 0.13 g of the catalyst solution was charged and stirred thoroughly using a Three-One motor. A-1 described above was added as an aromatic isocyanate compound, and the reaction was carried out while stirring and mixing at 500 rpm for 2 minutes. The evaluation results are shown in Table 3. The NCO Index, which is the ratio of the isocyanate equivalent to the hydroxyl group equivalent, was set to 0.8, and the isocyanate mass was calculated using Equation 1.

[0143]

[0144] (Pot Life) An isocyanate was added to a polyalkylene ether glycol and stirred at 300 rpm, and the time until the viscosity reached 10,000 mPa·s was measured.

[0145] (Temperature Rise After 1 Minute) Isocyanate was added to polyalkylene ether glycol, and the temperature rise after 1 minute was measured.

[0146] Examples 2-2 and 2-3 and Comparative Example 2-1 Polyurethanes were obtained in the same manner as in Example 2-1, except that the raw materials used in Example 2-1 were changed to those shown in Table 3. The evaluation results are shown in Table 3.

[0147] (Materials Used) (A) Isocyanate A-1: ​​Polymethylene polyphenyl polyisocyanate (p-MDI) [Millionate MR-200, manufactured by Tosoh Corporation, NCO content 30.8%]

[0148] (B) Polyalkylene ether glycols B-1: Polyethylene glycol (hydroxyl value 33 mg KOH / g, number average molecular weight 3,400, metal content potassium less than 1 ppm, sodium 23 ppm) B-2: Polyethylene glycol (hydroxyl value 36 mg KOH / g, number average molecular weight 3,100, metal content potassium 87 ppm, sodium less than 1 ppm) B-3: Polyethylene glycol (hydroxyl value 28 mg KOH / g, number average molecular weight 4,000, metal content potassium 425 ppm, sodium 3 ppm) B-4: Polyethylene glycol (hydroxyl value 33 mg KOH / g, number average molecular weight 3,400, metal content potassium 745 ppm, sodium 23 ppm) Urethane catalyst: Triethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.) Polypropylene glycol (Sanyo Chemical Industries, Ltd., Sannix PP-2000)

[0149]

[0150] The results shown in Table 3 indicate that by keeping the metal components, such as alkali metals, at 500 ppm by mass or less, the phase state at 80°C is good and the pot life is maintained. In particular, Examples 2-1 and 2-2, in which the metal content is 100 ppm by mass or less, exhibit extremely long and sufficient pot life. On the other hand, Example 2-3, due to its relatively high metal content, exhibited a shorter pot life than Examples 2-1 and 2-2. In contrast, the polyurethane of Comparative Example 2-1 exhibited an extremely short pot life due to the presence of metal components, such as alkali metals, exceeding 500 ppm by mass. Furthermore, at the temperature 1 minute after the start of the urethanization reaction, the polyurethane of Comparative Example 2-1 exhibited an extremely high value, while the polyurethanes of the Examples exhibited low values. In particular, Examples 2-1 and 2-2 exhibited extremely low values. Therefore, it was demonstrated that the polyurethanes of the present invention are capable of suppressing heat generation during the urethanization reaction and preventing runaway. As described above, the polyurethane of the present invention is shown to be a polyurethane that does not go out of control during the urethanization reaction, can suppress heat generation, and has a long pot life.

[0151] Experimental Example 3 Production of Polyurethane Elastomer for Heat Storage Material 170.0 g of commercially available polyalkylene ether glycol (PEG4000S manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value 33 mg KOH / g (number average molecular weight 3400)) heated to 65°C was weighed into a disposable cup. Separately, triethylenediamine manufactured by Tokyo Chemical Industry Co., Ltd. and Sannix PP-2000 (polypropylene glycol manufactured by Sanyo Chemical Industries, Ltd.) were weighed in a ratio of 1:9 as urethanation catalysts, dissolved at 80°C, and returned to room temperature. 0.26 g of this catalyst solution was then charged and thoroughly mixed by stirring using a Three-One motor. To this was added 8.2 g of Millionate MR-200 (NCO content 30.8%), a polymethylene polyphenyl polyisocyanate (hereinafter referred to as "p-MDI") manufactured by Tosoh Corporation, as an aromatic compound having a polyfunctional isocyanate group (average number of functional groups: 2.8), and the mixture was reacted while stirring at 300 rpm for 5 minutes. The NCO Index, which is the ratio of the isocyanate equivalent to the hydroxyl group equivalent, was set to 0.6, and the isocyanate weight was calculated using the above formula 1.

[0152] A silicone release film was then placed on a glass plate, and a silicone mold (dimensions: 15 cm x 15 cm, thickness: 2 mm) was placed on top of that. The resulting mixture was poured into the mold, covered with a release film and then a glass plate, and then a weight was placed on the glass plate above the mold, and the mixture was allowed to cure for an additional 30 minutes. The next day, the mixture was removed from the silicone mold to obtain a polyurethane elastomer for heat storage materials (dimensions: 15 cm x 15 cm, thickness: 2 mm). The mixture was then aged at room temperature for one week and used for evaluation. The DSC curve of the produced polyurethane elastomer during heating is shown in Figure 4. The DSC curve during cooling is also shown in Figure 5. The endothermic peak temperature was 56°C, and the exothermic peak temperature was 41°C. Other evaluation results are shown in Table 4.

[0153]

[0154] <Examples 3-1 to 3-6> A simulation of the temperature rise suppression effect was performed under the following conditions. (Molded body) The temperature rise during 2C charging was calculated by simulation when a phase change material with a melting enthalpy of 100 J / g, which begins to appear at 40°C and has a peak at 53°C, was used as a potting material filled around a cylindrical cell. Computational fluid dynamics software (product name: STAR-CCM+, Siemens) was used for the simulation.

[0155] (Battery Cell and Charging Conditions) The cell dimensions were 21 mm in diameter and 70 mm in height, including the 0.3 mm case thickness. The cell's internal components consist of a positive electrode, a negative electrode, a separator, and an electrolyte. However, for simplicity, the simulation treated them as a single component, and calculations were performed with anisotropic thermal conductivity. A 1 / 6 cake-cut model, as shown in Figure 4, was used for the calculations. In Figure 4, the circles represent cells, and the space between the cells is filled with phase change material. The heat generated by each cell during 2C charging was set to a constant 4.4 W for 30 minutes, and the initial temperature of each component constituting the module was set to 35°C. Note that these conditions assume charging immediately after operation has ended. The bottom of the cell and the bottom of the phase change material (PCM) are assumed to be in contact with the cooling mechanism. The refrigerant temperature was 30°C, and the heat transfer coefficient was 800 W / m. ２ The boundary condition for forced convection was set at K. The upper surface was assumed to be a space, with an air temperature of 35°C and a heat transfer coefficient of 10 W / m ２ The boundary was set to K for natural convection. The cut surface was set to a symmetric boundary. Also, assuming that an insulating sheet was installed on the bottom surface inside the case and the cell contact area, the thermal resistance was set to 1.0 x 10 －４ m ２ The thermal conductivity of the phase change material compact was set to 4.0 W / m K, 8.0 W / m K, and 12.0 W / m K, respectively, and a charging simulation was performed to determine the average temperature of the cell after charging for 1,800 seconds at 2 C for each thermal conductivity. Table 6 shows the average temperature difference for Examples 3-1 to 3-6.

[0156]

[0157]

[0158] The above simulation was performed using the flame retardant content [vol%] in the phase change material molded body and the latent heat [kJ / kg] of the phase change material as variables. As the flame retardant content in the phase change material molded body increased, the proportion of the phase change material in the phase change material molded body decreased, and the latent heat of the phase change material molded body decreased. As the latent heat of the phase change material increased, the latent heat of the phase change material molded body also increased.

[0159] [Experimental Example 4] <Example 4-A-1> (Production of polyurethane elastomer for heat storage material) In a disposable cup, 100.0 g of commercially available polyalkylene ether glycol ("PEG4000S" manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value 33 mg KOH / g (number average molecular weight 3400)) heated to 65 ° C. was weighed. Separately, triethylenediamine manufactured by Tokyo Chemical Industry Co., Ltd. and Sannix PP-2000, a polypropylene glycol manufactured by Sanyo Chemical Industries, Ltd., were weighed in a ratio of 1:7 as a urethanization catalyst, dissolved at 80 ° C., and returned to room temperature. 0.16 g of the catalyst solution and 1.07 g of 3-(glycidyloxy)propyltrimethoxysilane (hereinafter referred to as "compound 1-1"), a silane coupling agent, were charged as an adhesive, and the mixture was stirred and thoroughly mixed using a three-one motor. To this was added 6.4 g of Millionate MR-200 (NCO content 30.8%), a polymethylene polyphenyl polyisocyanate (hereinafter referred to as "p-MDI") manufactured by Tosoh Corporation, an aromatic compound having a polyfunctional isocyanate group (average functional group number 2.8), and the mixture was allowed to react while stirring at 500 rpm for 1 minute to produce a heat storage material. The NCO Index of the polyurethane was set to 0.8, and the ratio of the total equivalent number of isocyanate groups to the total equivalent number of active hydrogen groups in the heat storage material (functional group equivalent ratio) was calculated taking into account the added adhesive.

[0160] (Preparation of test specimen) The mixture was applied to an aluminum adherend (A1050P (dimensions: 1.6 × 25 (±0.5) × 100 (±0.5)) manufactured by Nippon Test Panel Co., Ltd.) that had been preheated to 50°C on a hot plate, and the aluminum adherend was attached with an overlap length of 12.5 mm and fixed with clips. The specimen was left to age at room temperature for one week and used as a test specimen for evaluation.

[0161] (Tensile shear adhesive strength test) Using the test pieces prepared above, the tensile shear adhesive strength of the heat storage material was measured by the method described above. The evaluation results are shown in Table 7.

[0162] (Differential scanning calorimetry) 5 mg of the produced heat storage material was sampled and sealed in an aluminum pan for measurement. By heating under a nitrogen atmosphere, an aluminum pan containing about 5 mg of sample was heated from 25 ° C. to 80 ° C. at a heating rate of 1 ° C. / min and held for 1 minute, and then cooled from 80 ° C. to 25 ° C. at a heating rate of 1 ° C. / min. Then, the temperature was again raised from 25 ° C. to 80 ° C. at a heating rate of 1 ° C. / min and held for 1 minute, and the endothermic peak temperature (melting point) was determined from the DSC curve obtained by this heating. Specifically, the maximum point of the endothermic peak in the range of 30 ° C. to 60 ° C. was determined, and the temperature at this maximum point was taken as the endothermic peak temperature (melting point). Next, the sample was cooled to -10 ° C. at a heating rate of 1 ° C. / min and held for 1 minute. The heat quantity corresponding to the area under the endothermic peak in the DSC curve was divided by the sample mass, and the enthalpy of fusion ΔH was calculated in J / g units. The evaluation results are shown in Table 7.

[0163] <Examples 4-A-2 to 4-A-5> Heat storage materials were produced in the same manner as in Example 4-A-1, except that the adhesive described below was used and the amount of isocyanate was adjusted to achieve the functional group equivalent ratio of the heat storage material shown in Table 1. The evaluation results are shown in Table 7.

[0164] (Adhesive) Compound 1-2: 3-aminopropyltrimethoxysilane Compound 1-3: N,N',N''-tris(3-trimethoxysilylpropyl)isocyanuric acid Compound 1-4: 3-isocyanatopropyltriethoxysilane Compound 1-5: N-(2-aminoethyl)-3-aminopropyltrimethoxysilane

[0165]

[0166] <Examples 4-B-1 to 10> Heat storage materials were produced in the same manner as in Example 4-A-2, except that the amount of isocyanate was adjusted to achieve the functional group equivalent ratio of the heat storage material shown in Table 8 and the adherend for the tensile shear adhesive strength test shown in Table 8 was used. The evaluation results are shown in Table 8.

[0167]

[0168] Examples 4-A-1 to 4-A-5 demonstrated that adhesive heat storage materials can be provided. Therefore, adherends can be fixed using the heat storage material. Furthermore, heat storage materials (compounds 1-2 to 1-5) containing adhesives with groups capable of forming bonds with polyurethane partial structures were shown to have high tensile shear adhesive strength. Therefore, it is believed that the adherend can be maintained in a fixed state even against external impact, and efficient heat absorption by the adherend can be expected. Examples 4-A-1 to 4-A-10 demonstrated that tensile shear adhesive strength can be maximized by the relationship between the chemical structure of the adhesive and the type of adherend, and the adhesive content.

[0169] [Experimental Example 5] <Experimental Example 5-1> (Production of polyurethane elastomer for heat storage material) 100.0 g of commercially available polyalkylene ether glycol ("PEG4000S" manufactured by Sanyo Chemical Industries, Ltd., hydroxyl value 33 mg KOH / g (number average molecular weight 3400)) heated to 65 ° C. and 30 g of 1,3-phenylene bis (diphenyl phosphate) as a predetermined flame retardant were weighed into a disposable cup. Separately, triethylenediamine manufactured by Tokyo Chemical Industry Co., Ltd. and Sannix PP-2000, a polypropylene glycol manufactured by Sanyo Chemical Industries, Ltd., were weighed in a ratio of 1:7 as a urethanization catalyst, and 0.45 g of a catalyst solution dissolved at 80 ° C. and returned to room temperature was charged, and the mixture was stirred using a Three-One motor to thoroughly mix. To this was added 6.4 g of Millionate MR-200 (NCO content 30.8%), a polymethylene polyphenyl polyisocyanate (hereinafter referred to as "p-MDI") manufactured by Tosoh Corporation, which is an aromatic compound having a polyfunctional isocyanate group (average number of functional groups: 2.8). The mixture was reacted while stirring at 500 rpm for 1 minute to produce a heat storage material. The NCO Index of the polyurethane was 0.8.

[0170] (Evaluation of Dispersibility) The dispersibility of the flame retardant in the PEG prepared in each example was evaluated visually.

[0171] (Bleed-out evaluation) The sheets produced in each example were left to stand at 23°C for 24 hours, and then visually inspected and evaluated according to the following evaluation criteria: (Evaluation criteria) 1: No change 2: No liquid visible, but glossy surface 3: Liquid visible on the surface 4: Liquefied and solid areas mixed (between evaluations 3 and 5) 5: Completely liquefied

[0172] (Combustion test) Using the test specimen prepared above, evaluation is carried out by a 20 mm vertical combustion test based on UL94. Specifically, a test specimen (125 mm x 13 mm x 2.0 mm) prepared using the heat storage material of the present invention is attached vertically to a clamp, and a 20 mm flame is applied for 10 seconds to measure the combustion time. (Overall evaluation) ×: Combustion time in the combustion test is longer than 30 seconds or the test is unsuccessful △: Combustion time is longer than 10 seconds and 30 seconds or less ◯: Combustion time is 10 seconds or less ⊚: Combustion time is 10 seconds or less and bleed-out evaluation is 1

[0173] <Experimental Examples 5-2 to 5-4> In Experimental Example 5-2, a heat storage material was produced in the same manner as in Experimental Example 5-1, except that the flame retardant listed in Table 9 was used. In Experimental Examples 5-3 and 5-4, a heat storage material was produced in the same manner as in Experimental Example 5-1, except that the flame retardant listed in Table 9 was used and the PEG containing the flame retardant was heated to 60°C and mixed, and then cooled to room temperature. The heat storage material produced in Experimental Example 5 showed the same melting temperature and melting enthalpy as Experimental Example 3, converted into the polyurethane content. The evaluation results are shown in Table 9.

[0174]

[0175] Experimental Example 5 demonstrated that the dispersibility of the flame retardant correlates with the combustion time of the heat storage material. A combustion time of 30 seconds or less can be considered self-extinguishing, which is believed to contribute to preventing the spread of fire in the cell. Furthermore, it was shown that when blending a flame retardant into polyalkylene ether glycol, melting the flame retardant by heating facilitates dispersion of the flame retardant in the polyalkylene ether glycol. Note that under the manufacturing conditions of Experimental Example 5, the flame retardant precipitated in Experimental Example 5-4, so a combustion test was not performed. However, it is believed that heating the flame retardant to its melting point can enable dispersion in the polyalkylene ether glycol. Furthermore, a design that prevents the flame retardant from bleeding out can also be easily applied to the potting process of battery packs.

[0176] According to the present invention, a heat storage material that is both heat-absorbing and flame-retardant can be provided. That is, the heat storage material of the present invention is useful as a heat storage material that can improve heat storage performance and suppress shape change due to heating and cooling, and can maintain heat-absorbing properties while also being flame-retardant. Therefore, it is useful as a heat storage material, a heat storage molding, or a coolant in a battery pack, and is a technology of great industrial value.

[0177] 200 Recess 300 Hollow portion 400 Cylindrical battery (single cell) 500 Housing 600 Composition (before curing) 610 Polyurethane, polyurethane composition for heat storage material, heat storage molding (support structure) 700 Battery pack 800 Nozzle L １　 Distance between the centers of the recess openings L ２　 Distance between cells L ３　 Center distance of hollow section

Claims

1. A heat storage material containing polyurethane, wherein the polyurethane undergoes a solid-solid phase transition in the 20 to 80°C temperature range in differential scanning calorimetry, the enthalpy change associated with the phase transition is 20 J / g or more, and the burning time of a test piece measured by the following measurement method is 60 seconds or less. (Measurement method) A test piece (125 mm x 13 mm x 2.0 mm) is attached vertically to a clamp and exposed to a 20 mm flame for 10 seconds, and the burning time is measured.

2. The heat storage material according to claim 1, wherein the polyurethane contains structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyol having a melting point of 30°C or higher.

3. The heat storage material according to claim 2, wherein the mass fraction of the structural unit (B) is 50 mass % or more and 99 mass % or less relative to the total mass of the structural units (A) and (B).

4. The heat storage material according to claim 2, wherein the structural unit (A) includes a structural unit derived from polymethylene polyphenyl polyisocyanate.

5. The heat storage material according to claim 2, wherein the structural unit (B) includes a structural unit derived from a polyalkylene ether glycol.

6. The heat storage material according to claim 1, wherein the polyurethane comprises structural units (A) derived from an aromatic polyisocyanate compound having an average functionality of 2.1 or more and structural units (B) derived from a polyol having a melting point of 30°C or more, and the isocyanate index, which is the ratio of the isocyanate group equivalent (II) of the structural unit (A) to the hydroxyl group equivalent (I) of the structural unit (B), is 0.4≦(II) / (I)≦1.

1.

7. The heat storage material according to claim 1, further comprising a flame retardant, the melting point of which is 200°C or lower.

8. The heat storage material according to claim 1, further comprising a flame retardant, the melting point of which is 30 to 200°C.

9. The heat storage material according to claim 1, further comprising a flame retardant, wherein the absolute value of the difference between the melting point of said flame retardant and the melting point of said polyalkylene ether glycol is 0 to 100°C.

10. The heat storage material according to claim 1, further comprising a flame retardant, wherein the absolute value of the difference between the melting point of said flame retardant and the melting point of said polyurethane is 0 to 100°C.

11. The heat storage material according to claim 1, further comprising a flame retardant, wherein the ratio of the content of an element corresponding to the flame retardant in the heat storage material based on XPS measurement to the content based on XRF measurement, as measured by the following method, is 0.5 to 1.5: (Method of measurement) A test piece measuring 10 mm x 10 mm x 5.0 mm is cut out from the heat storage material, and the content of the element corresponding to the flame retardant is measured using an X-ray fluorescence analyzer (XRF) and an X-ray photoelectron spectroscopy (XPS).

12. The heat storage material according to claim 1, further comprising a flame retardant, wherein the coefficient of variation of the content of the element corresponding to the flame retardant in the heat storage material measured by the following method is 0.15 or less: (Measurement method) Five test pieces measuring 10 mm x 10 mm x 5.0 mm are cut out from the heat storage material, and the content of the element corresponding to the flame retardant is measured using an X-ray photoelectron spectroscopy (XPS).

13. The heat storage material according to claim 1, which has a tensile shear adhesive strength of 0.40 MPa or more as measured by the following measurement method: (Measurement method) Two adherend test pieces measuring 25 mm x 100 mm x 1.6 mm are prepared, and the heat storage material is applied to the overlapping portions of the adherend test pieces so that the overlapping length of the adherend test pieces is 12.5 mm and the thickness of the heat storage material is 0.2 mm, and then cured. Each adherend test piece is fixed at a region 50 mm or more away from the edge of the overlapping portion as a gripping portion, and tested at a tensile speed of 5 mm / min. The tensile shear load value obtained is expressed as the adhesive area (mm ２ ) to obtain the tensile shear bond strength value.

14. A battery pack comprising a plurality of cells and the heat storage material according to any one of claims 1 to 13.

15. A composition comprising an aromatic polyisocyanate compound having an average functionality of 2.1 or more, a polyalkylene ether glycol, and a flame retardant, wherein the mass fraction of the polyalkylene ether glycol is 50% by mass or more and 99% by mass or less relative to the total mass of the aromatic polyisocyanate compound having an average functionality of 2.1 or more and the polyalkylene ether glycol, and the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyalkylene ether glycol is 0 to 100°C.

16. The composition according to claim 15, wherein the melting point of the polyalkylene ether glycol is 30°C or higher and 100°C or lower.

17. The composition according to claim 15, wherein the absolute value of the difference between the melting point of said flame retardant and the melting point of said polyalkylene ether glycol is 0 to 60°C.

18. The composition according to claim 15, wherein the melting point of the polyalkylene ether glycol is 30°C or higher and 100°C or lower, and the absolute value of the difference between the melting point of the flame retardant and the melting point of the polyalkylene ether glycol is 0 to 60°C.

19. A composition kit comprising: a first container filled with composition (a) containing an aromatic polyisocyanate compound having an average functionality of 2.1 or more; and a second container filled with polyol composition (b) containing a polyalkylene ether glycol and a flame retardant, wherein the ratio of the volume of the second container to the volume of the first container is 5 to 15.

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