Organophosphorus compound

Abstract

[Problem] To provide: a flame retardant which has excellent flame retardancy and contains, as an active ingredient, an organic phosphoric acid compound reduced in environmental burden; a flame-retardant polyurethane resin composition containing the flame retardant; and a synthetic leather obtained using the flame-retardant polyurethane resin composition.　[Solution] A polyurethane resin composition containing a flame retardant that contains, as an active ingredient, an organophosphorus compound which is a salt obtained by reacting phytic acid with an aliphatic polyamine, preferably an aliphatic polyamine represented by R-(NH2)x (wherein R is a C2-C12 linear aliphatic hydrocarbon group and X is an integer of 2-4).　

Description

Organophosphorus compounds

[0001] The present invention relates to an organophosphorus compound useful as an active ingredient of a flame retardant used in resin products such as synthetic leather, a flame retardant containing the same, a flame-retardant polyurethane resin composition, and synthetic leather. More specifically, the present invention relates to an active ingredient of a flame retardant that uses plant-derived phytic acid and has a reduced environmental impact.

[0002] Flammable polymeric materials have traditionally been widely used in automotive parts, electrical appliances, textile products, packaging films, and other products, and flame retardants are often incorporated into these materials to ensure safety. For example, synthetic leather made from polyurethane resin, which is used in automotive seating, requires high flame retardancy, so the development of superior flame retardants has been sought. Furthermore, with the increasing attention being paid to measures against global warming and reducing environmental impact in recent years, safe materials with low environmental impact are desired.

[0003] Although chlorine-based and bromine-based flame retardants are available for polymer materials, phosphorus-based flame retardants are widely used due to the problem of generating harmful dioxins when materials are burned or incinerated. For example, one method of imparting flame retardancy to polyurethane resins is to incorporate a liquid flame retardant such as a phosphoric acid ester (Patent Document 1).

[0004] However, phosphorus-based flame retardants are generally volatile, and therefore there is a problem of pollution due to volatilized flame retardants, and there is also concern about the generation of toxic phosphine during combustion.

[0005] In response to this, flame retardants containing phytic acid, a plant-derived component, are known. For example, a flame retardant containing a nitrogen-containing basic organic compound salt of phytic acid is known (Patent Document 2). Also proposed are a flame retardant containing a salt of phytic acid and a cationic amphiphilic substance as an active ingredient (Patent Document 3), and a phytic acid derivative containing a phosphate ester substituent (Patent Document 4).

[0006] However, these conventional flame retardants using phytic acid have the following problems. The phytate salt of Patent Document 2 is a salt of phytic acid and an amino acid, and is a flame retardant with moisture-retaining properties derived from amino acids. When such a highly moisture-retaining flame retardant is used in a two-component polyurethane, the isocyanate raw material reacts with water, which may inhibit the polyurethane reaction. Furthermore, when used in synthetic resins, it may cause foaming during extrusion or injection molding, resulting in a decrease in the strength of the molded product.

[0007] Patent Document 3 describes a salt of phytic acid and a diamine having a glycol chain as the main chain, which has hydrophilicity derived from the glycol chain and may cause the same problems as described above. Patent Document 4 describes a compound in which one molecule of phytic acid is bound to one molecule of a substituent having an alkyl group.

[0008] In response to recent environmental issues, various polyurethane resins with a high biomass ratio that use plant-derived raw materials have been proposed (e.g., Patent Document 5). It is hoped that the biomass ratio can be further increased by developing a plant-derived flame retardant suitable for such biomass polyurethane resins.

[0009] Japanese Patent Application Laid-Open No. 2022-056074 Japanese Patent Application Laid-Open No. 2002-201475 Japanese Patent No. 4997440 Japanese Patent Application Laid-Open No. 2011-079950 Japanese Patent Application Laid-Open No. 2011-226047

[0010] The present inventors, in the course of extensive research aimed at contributing to carbon neutrality aimed at combating global warming and reducing the environmental burden, have developed a biomass polyurethane resin obtained using plant-derived components and have also diligently developed a flame retardant suitable for this resin and with low environmental impact. An object of the present invention is to provide a flame retardant that is excellent in flame retardancy, safe, and with low environmental impact, a flame-retardant polyurethane resin composition containing the flame retardant, and synthetic leather using the same.

[0011] As a result of extensive research, the present inventors have found that a salt of an aliphatic polyamine and phytic acid not only has excellent flame retardancy but also reduces the environmental load, and have thus completed the present invention.

[0012] That is, the present invention relates to the following phytic acid derivatives, a flame-retardant polyurethane resin composition containing the same, and synthetic leather: (1) An organophosphorus compound comprising a salt of a chain aliphatic polyamine and phytic acid.

[0013] (2) The chain aliphatic polyamine is R—(NH ２ )x (wherein R is a chain aliphatic hydrocarbon group having 2 to 12 carbon atoms which may include branches, and X is an integer of 2 to 4). (3) The organophosphorus compound according to (1), wherein the chain aliphatic polyamine is a linear aliphatic diamine having 2 to 12 carbon atoms.

[0014] (4) The organic phosphorus compound according to (1), which comprises a structure in which at least two structural units derived from phytic acid are crosslinked by a structural unit derived from a chain aliphatic polyamine. (5) The organic phosphorus compound according to (1), wherein the salt has a structure in which the structural units derived from a chain aliphatic polyamine and the structural units derived from phytic acid are present in a ratio of 1:1 to 8:1 (equivalent ratio).

[0015] (6) The organophosphorus compound according to (1), wherein the salt is a salt prepared by mixing a chain aliphatic polyamine and phytic acid in a molar ratio of 1:1 to 5:1. (7) The organophosphorus compound according to (1), wherein the organophosphorus compound has at least two decomposition temperatures, at least one of which is in the range of 200 to 400°C.

[0016] (8) A flame retardant comprising the organophosphorus compound according to any one of (1) to (7). (9) A flame-retardant polyurethane resin composition comprising the flame retardant according to (8).

[0017] (10) The flame-retardant polyurethane resin composition according to (9), wherein the content of the flame retardant is 25 mass % or less based on the total amount of the flame-retardant polyurethane resin composition. (11) Synthetic leather using the flame-retardant polyurethane resin composition according to (9).

[0018] <Regarding environmental impact> The organophosphorus compound of the present invention is made from plant-derived phytic acid and is useful as a flame retardant with low environmental impact. Furthermore, by forming a salt with a plant-derived polyamine, the biomass ratio of the flame retardant itself can be further increased. By blending this with a biomass-based polyurethane resin, a flame-retardant polyurethane resin composition with an extremely high biomass ratio and synthetic leather using the same can be obtained.

[0019] Furthermore, by blending it with a polyurethane resin that uses plant-derived polyisocyanate components and polyol components as raw materials, it is possible to obtain an environmentally friendly flame-retardant polyurethane resin composition that not only has excellent flame retardancy but also has an extremely high biomass ratio, and synthetic leather made from the same.

[0020] <Regarding decomposition temperature> The organophosphorus compound of the present invention contains a structure in which at least two structural units derived from phytic acid are crosslinked with a structural unit derived from a chain aliphatic polyamine (a structure in which at least two molecules of phytic acid are bonded via one molecule of a chain aliphatic polyamine), and is thought to form a three-dimensional polymeric compound salt containing a plurality of such structures, and has at least two decomposition temperatures.

[0021] Although the reason for the existence of at least two decomposition temperatures is not entirely clear, it is thought that as the temperature rises, cross-linking bonds are broken, followed by decomposition of phytic acid. Since the flame retardant effect is exerted when phytic acid decomposes, an excellent flame retardant effect can be exerted when the higher decomposition temperature is higher than the thermal decomposition temperature (melting temperature) of the resin to be imparted with flame retardancy.

[0022] The flame retardant using the organic phosphorus compound of the present invention has a decomposition temperature close to or higher than the thermal decomposition temperature of the resin, and therefore the flame retardant effect is not lost due to decomposition before the resin at high temperature decomposes or melts, and therefore the flame retardant effect can be efficiently exerted, thereby making it possible to obtain a resin composition in which the amount of flame retardant added is reduced while maintaining the flame retardant effect.

[0023] <Regarding Water Absorption and Deliquescence> Because the organophosphorus compound of the present invention has low water absorption, when used as a flame retardant in a synthetic resin, there is no risk of problems such as foaming during extrusion molding or injection molding, which can lead to a decrease in the strength of the molded product. In particular, when blended with a polyurethane resin, the isocyanate raw material component does not react with water to inhibit the polyurethane reaction. Furthermore, because the organophosphorus compound of the present invention does not have deliquescence, it has good dispersibility when blended with a synthetic resin, and excellent handleability and high flame retardancy can be expected.

[0024] FIG. 1 is a graph showing the NMR measurement results of the amine phytic acid salt synthesized with the raw material diamine in Example 1 of the present invention. FIG. 2 is a graph showing the DSC measurement results of the amine phytic acid salt in Example 1 of the present invention. FIG. 3 is a graph showing the DSC measurement results of the amine phytic acid salt in Example 2 of the present invention. FIG. 4 is a graph showing the DSC measurement results of the amine phytic acid salt in Example 3 of the present invention. FIG. 5 is a graph showing the DSC measurement results of the amine phytic acid salt in Example 4 of the present invention. FIG. 6 is a graph showing the DSC measurement results of the amine phytic acid salt in Comparative Example 1 of the present invention. FIG. 7 is a graph showing the DSC measurement results of the amine phytic acid salt in Comparative Example 2 of the present invention.

[0025] 1. Organic Phosphorus Compounds (1) Phytic Acid The phytic acid used in the present invention is a compound represented by the following formula (Chemical Formula 1).

[0026]

[0027] Phytic acid having the above structure and containing phosphorus element is a plant-derived substance, and is contained in large amounts in grains and beans in the form of water-insoluble calcium salts or magnesium salts. It can be easily extracted as water-soluble phytic acid by acid treatment. Since it is particularly abundant in rice bran, phytic acid produced by a known method using rice bran as a raw material can be used.

[0028] Phytic acid is a strongly acidic substance with an inositol hexaphosphate ester structure, and is far more acidic than phosphoric acid. However, because it is a natural product, it can be disposed of by simple neutralization.

[0029] (2) Linear Aliphatic Polyamine The linear aliphatic polyamine used in the present invention is not particularly limited as long as it is a compound having an aliphatic hydrocarbon group in the main chain and two or more amino groups, but is preferably a compound represented by the following formula (Chemical Formula 2):

[0030] (Chemical formula 2) R-(NH ２ ) x

[0031] In the above formula, R (main chain of the aliphatic polyamine) is a chain aliphatic hydrocarbon group which may contain a branched structure, and preferably has 2 to 12 carbon atoms, more preferably 6 to 12 carbon atoms, and even more preferably 10 to 12 carbon atoms.

[0032] The aliphatic hydrocarbon group of R may be linear or branched, but is preferably a linear aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be saturated or unsaturated, but is preferably a saturated aliphatic hydrocarbon group.

[0033] Specific examples of R include an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, and a dodecyl group.

[0034] In the above formula, X is an integer of 2 to 4. That is, X=2 (diamine), X=3 (triamine), and X=4 (tetramine) are included. X=2 (diamine) is particularly preferred.

[0035] The main chain (R) of the aliphatic polyamine is preferably composed of only a hydrocarbon chain, but R may also contain a urethane bond, an amide bond, an imide bond, or the like.

[0036] However, it is desirable that R does not contain functional groups containing oxygen atoms and / or sulfur atoms, such as carboxyl groups, hydroxyl groups, and sulfonic acid groups. Furthermore, even if R contains nitrogen-containing functional groups, it is desirable that R does not contain imino groups. Furthermore, from the viewpoint of water absorption, the main chain does not contain ether bonds such as alkylene glycol chains (e.g., ethylene glycol chains and propylene glycol chains).

[0037] The linear aliphatic polyamine used in the present invention is preferably a linear aliphatic diamine, specific examples of which include ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, tetramethylenediamine, 1,4-butanediamine, 1,5-pentamethylenediamine, hexamethylenediamine, 1,10-decanediamine, 1,11-undecanediamine, and 1,12-dodecanediamine.

[0038] Particularly preferred chain aliphatic polyamines are decanediamine and dodecanediamine. In addition to decanediamine, ethylenediamine and pentanediamine are also preferably used because they are derived from plants.

[0039] (3) Phytate (organic phosphorus compound) The organophosphorus compound of the present invention is a salt of a chain aliphatic polyamine and phytic acid (hereinafter referred to as "phytate"), which can be obtained by mixing a chain aliphatic polyamine and phytic acid in water, for example.

[0040] The phytate of the present invention thus obtained has a structure in which at least two structural units derived from phytic acid are crosslinked with a structural unit derived from a chain aliphatic polyamine, in other words, a structure in which at least two molecules of phytic acid are linked via one molecule of a chain aliphatic polyamine (hereinafter, sometimes referred to as a "1:2 adduct of polyamine and phytic acid").

[0041] The structure represented by the above chemical formula is formed by reacting a chain aliphatic polyamine with phytic acid in a predetermined ratio, and forming an ionic bond between the amino group of the chain aliphatic polyamine and the hydroxyl group of the phytic acid.

[0042] For example, when the chain aliphatic polyamine is a linear aliphatic diamine, one molecule of phytic acid can be bonded to each of the amino groups at both ends of the linear aliphatic diamine, for a total of two molecules of phytic acid. In this case, most of the amino groups of the linear aliphatic diamine are blocked by multiple molecules of phytic acid, and there are almost no free amino groups. In addition, considering the three-dimensional structure of the aliphatic hydrocarbon group that is the main chain of the linear aliphatic diamine, it is considered that there are few, or even almost no, cases in which the amino groups at both ends of the linear aliphatic diamine are bonded to different hydroxyl groups of the same phytic acid.

[0043] Phytic acid contains six phosphate ester groups, each of which has two hydroxyl groups, for a total of 12 hydroxyl groups, at least one of which bonds with the amino group of a linear aliphatic diamine.

[0044] The other hydroxyl groups of phytic acid can be bonded to the terminal amino groups of other linear aliphatic diamines. In the phytate of the present invention, any number of the 12 hydroxyl groups can bond with amino groups to form a salt. However, considering the bulkiness and steric hindrance between the molecules, not all of the 12 hydroxyl groups necessarily bond with the amino groups of the linear aliphatic diamine to form a salt. Preferably, in the phytate of the present invention, an average of 4 to 8 hydroxyl groups, more preferably an average of 6 to 8 hydroxyl groups, of the 12 hydroxyl groups of phytic acid form a salt with the amino groups.

[0045] The phytate of the present invention has a structure in which one phytic acid is bonded to another phytic acid via a linear aliphatic polyamine, and the other phytic acid is further bonded to a new phytic acid via another linear aliphatic polyamine. Furthermore, multiple hydroxyl groups of one phytic acid are bonded to a linear aliphatic diamine. Thus, the phytate of the present invention is considered to form a three-dimensional polymeric compound salt containing multiple structures in which multiple phytic acid molecules are crosslinked by a linear aliphatic diamine.

[0046] The phytate salt of the present invention having such a structure contains structural units derived from chain aliphatic polyamines and structural units derived from phytic acid in an equivalent ratio of preferably 4:1 to 8:1, more preferably 6:1 to 8:1. Particularly preferred is a structure in which two structural units derived from phytic acid are crosslinked by a structural unit derived from chain aliphatic polyamines, i.e., a 1:X adduct containing structural units derived from chain aliphatic polyamines and structural units derived from phytic acid in an equivalent ratio of 1:X (where X is 2 to 4). The molecular weight of the phytate salt is not necessarily limited.

[0047] (4) Preparation of Phytate The phytate of the present invention can be obtained by mixing a linear aliphatic polyamine and phytic acid in water. Preferably, the phytate is obtained by preparing the linear aliphatic polyamine and phytic acid in a molar ratio of 1:1 to 5:1. A more preferred ratio is 2:1 to 5:1, and an even more preferred ratio is 3:1 to 5:1.

[0048] The method for producing phytate is not particularly limited, but for example, an aqueous solution of phytic acid is prepared in a reaction vessel, and an aliphatic polyamine or its salt, or an aqueous solution thereof, or a water-soluble organic solution is added little by little while stirring, while taking care not to generate heat, to precipitate the phytate. The phytate obtained as a precipitate is separated by filtration or the like, washed with a solvent capable of dissolving the unreacted linear aliphatic polyamine, and then dried under reduced pressure to obtain the phytate.

[0049] (5) Decomposition Temperature The organophosphorus compound of the present invention, which is a phytate, preferably has at least two decomposition temperatures, namely, a relatively low first decomposition temperature and a higher second decomposition temperature.

[0050] Of the multiple decomposition temperatures, it is desirable that at least one decomposition temperature is preferably 200° C. or higher, more preferably 280° C. or higher, even more preferably 300° C. or higher, and particularly preferably 350° C. or higher. There is no particular upper limit to the decomposition temperature, but it is preferably 450° C. or lower, more preferably 420° C. or lower, and even more preferably 400° C. or lower.

[0051] Furthermore, it is desirable that the compound has at least two decomposition temperatures, with the relatively low first-stage decomposition temperature being in the range of preferably 120 to 300°C, more preferably 150 to 300°C, even more preferably 200 to 280°C, and particularly preferably 220 to 270°C, and the second-stage decomposition temperature being higher than the first-stage decomposition temperature being in the range of preferably 200 to 450°C, more preferably 280 to 420°C, even more preferably 300 to 400°C, and particularly preferably 350 to 400°C.

[0052] When there are two decomposition temperatures, the temperature difference between the relatively low first-stage decomposition temperature and the higher second-stage decomposition temperature is preferably 50°C or more, more preferably 70°C or more, even more preferably 100°C or more, and particularly preferably 120°C or more.

[0053] As described above, the organophosphorus compound of the present invention has at least two decomposition temperatures, and it is preferable that at least one of the decomposition temperatures is relatively high, thereby enabling the compound to exhibit excellent flame retardancy. Note that the decomposition temperature in the present invention is a value measured by thermogravimetry-differential scanning calorimetry (TG-DSC) in the temperature range of 50 to 500°C at a heating rate of 10°C / min.

[0054] The reason for the existence of at least two decomposition temperatures is not entirely clear, but it is thought that as the temperature rises, the bond between phytic acid and the linear aliphatic polyamine breaks in the first stage, causing the polymer compound structure to collapse, and then the decomposition of phytic acid occurs in the second stage.Since the flame retardant effect is exerted when phytic acid decomposes, a higher flame retardant effect can be exerted near the higher decomposition temperature.

[0055] When the organophosphorus compound of the present invention, consisting of phytate, is blended as a flame retardant in a resin, its decomposition temperature is close to or higher than the thermal decomposition temperature (or melting temperature) of the resin, and therefore the flame retardant effect is not lost due to decomposition before the resin is decomposed or melted at a high temperature, thereby efficiently exerting the flame retardant effect. Therefore, a flame-retardant resin composition can be obtained in which the amount of flame retardant added is reduced while maintaining the flame retardant effect.

[0056] (6) Water Absorbency (Deliquescence) The organophosphorus compound of the present invention exhibits low water absorbency. In particular, when a linear aliphatic polyamine that does not contain an ether bond, such as an alkylene glycol chain such as an ethylene glycol chain or a propylene glycol chain, in its main chain or that does not contain a functional group containing an oxygen atom and / or a sulfur atom is selected, the compound will not deliquesce even when left in air for a long period of time.

[0057] When such an organophosphorus compound having low water absorption is used as a flame retardant in a synthetic resin, there is no risk of problems such as foaming during extrusion or injection molding, which can lead to a decrease in the strength of the molded product. In particular, when the compound is added to a polyurethane resin, the isocyanate raw material component does not react with water to inhibit the polyurethane reaction. Therefore, the organophosphorus compound of the present invention can be suitably used as a flame retardant for resins.

[0058] 2. Flame Retardant The flame retardant of the present invention contains, as an active ingredient, an organophosphorus compound consisting of the above-mentioned phytate. The flame retardant of the present invention is suitable for use in flame retarding synthetic resins such as thermoplastic resins and thermosetting resins. There are no limitations on the synthetic resins that can be used, and examples include general-purpose synthetic resins such as polyester resins, polyamide resins, polyolefin resins, acrylic resins, polystyrene resins, and polyurethane resins. A particularly preferred synthetic resin is polyurethane resin.

[0059] 3. Flame-Retardant Polyurethane Resin Composition The flame-retardant polyurethane resin composition of the present invention contains at least a reaction product obtained by reacting raw material components for a polyurethane resin, including a polyisocyanate component and a polyol component, and a flame retardant.

[0060] (1) Polyisocyanate Component Examples of the polyisocyanate component include diisocyanates such as aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates.

[0061] The aliphatic or alicyclic diisocyanate preferably has a carbon number of 4 to 30. Examples of the aliphatic diisocyanate include tetramethylene diisocyanate, 1,5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), 2,2,4- (or 2,4,4-) trimethyl-1,6-hexamethylene diisocyanate, and lysine diisocyanate.

[0062] Examples of alicyclic diisocyanates include isophorone diisocyanate, hydrogenated xylene diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, 1,4-diisocyanate cyclohexane, 1,3-bis(diisocyanate methyl) cyclohexane, and 4,4'-dicyclohexylmethane diisocyanate.

[0063] Examples of aromatic diisocyanates include 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, phenylene diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, and polymethylene polyphenyl polyisocyanate.

[0064] These diisocyanates may be used alone or in combination. Of these, 1,6-hexamethylene diisocyanate is preferred because of its weather resistance and ease of industrial availability. Furthermore, in consideration of the impact on the environment, it is also preferred to use environmentally friendly 1,5-pentamethylene diisocyanate, which is a plant-derived isocyanate.

[0065] The content of the polyisocyanate component is preferably 35 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more, per 100 parts by mass of the polyurethane resin raw material component of the present invention, and is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and particularly preferably 70 parts by mass or less.

[0066] (2) Polyol Component The polyol component is used as a raw material component of the reaction product that constitutes the flame-retardant polyurethane resin composition of the present invention.

[0067] Examples of the polyol component include aromatic polyols, alicyclic polyols, aliphatic polyols, polyether polyols, polyester polyols, polylactone polyols, acrylic polyols, epoxy polyols, polycarbonate polyols, urethane polyols, etc. These may be used alone or in combination of two or more.

[0068] Examples of aromatic polyols include bisphenol A, bisphenol F, phenol novolac, and cresol novolac.

[0069] Examples of alicyclic polyols include cyclohexanediol, methylcyclohexanediol, isophoronediol, dicyclohexylmethanediol, and dimethyldicyclohexylmethanediol.

[0070] Examples of the aliphatic polyol include ethylene glycol, propylene glycol, butanediol, pentanediol, and hexanediol.

[0071] Examples of polyether polyols include polymers obtained by ring-opening polymerization of at least one alkylene oxide, such as ethylene oxide, propylene oxide, or tetrahydrofuran, in the presence of at least one low-molecular-weight active hydrogen compound having two or more active hydrogens. Examples of low-molecular-weight active hydrogen compounds having two or more active hydrogens include diols such as bisphenol A, ethylene glycol, propylene glycol, butylene glycol, and 1,6-hexanediol, triols such as glycerin and trimethylolpropane, and amines such as ethylenediamine and butylenediamine.

[0072] Examples of polyester polyols include polyester polyol resins obtained by a condensation reaction of a dibasic acid selected from carboxylic acids such as succinic acid, adipic acid, sebacic acid, dimer acid, maleic anhydride, fumaric anhydride, isophthalic acid, and terephthalic acid, either alone or in combination, with a polyhydric alcohol such as ethylene glycol, propylene glycol, diethylene glycol, neopentyl glycol, trimethylolpropane, and glycerin, either alone or in combination; polycaprolactone obtained by ring-opening polymerization of ε-caprolactone and a polyhydric alcohol; and esters of an aliphatic compound having a hydroxyl group, such as castor oil, with a polyhydric alcohol.

[0073] Examples of polylactone polyols include polypropiolactone glycol, polycaprolactone glycol, and polyvalerolactone glycol.

[0074] Examples of acrylic polyols include those obtained by copolymerizing a polymerizable monomer having one or more active hydrogen atoms in one molecule with a monomer copolymerizable therewith. For example, (i) a single or mixture of acrylic acids selected from acrylic esters having active hydrogen atoms, such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxybutyl acrylate; methacrylic esters having active hydrogen atoms, such as 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and 2-hydroxybutyl methacrylate; methacrylic acids and acrylic acids having polyvalent active hydrogen atoms, such as acrylic acid monoester or methacrylic acid monoester of glycerin, and acrylic acid monoester or methacrylic acid monoester of trimethylolpropane; and (ii) methyl acrylate, ethyl acrylate, isopropyl acrylate, acrylic acid monoester ... Examples of the acrylic polyol resins include acrylic polyol resins obtained by polymerizing, alone or in combination, a monomer selected from the group consisting of acrylic acid esters such as n-butyl methacrylate and 2-ethylhexyl acrylate; and methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, and n-hexyl methacrylate, in the presence or absence of (iii) a monomer selected from the group consisting of unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and itaconic acid, unsaturated amides such as acrylamide and N-methylolacrylamide, and polymerizable monomers such as styrene, vinyltoluene, vinyl acetate, and acrylonitrile, alone or in combination.

[0075] Examples of epoxy polyols include novolak-type, β-methylepichlorohydrin-type, cyclic oxirane-type, glycidyl ether-type, glycidyl ester-type, glycol ether-type, epoxidized aliphatic unsaturated compound-type, epoxidized aliphatic ester-type, polycarboxylic acid ester-type, aminoglycidyl-type, and resorcinol-type epoxy resins.

[0076] Examples of polycarbonate polyols include polyols obtained by dealcoholization reaction of hydroxyl group-containing compounds such as ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, octanediol, and nonanediol with diethylene carbonate, dipropylene carbonate, etc. Further examples include polycarbonate polyols obtained using aromatic polyhydric alcohols such as bisphenol A and aliphatic / alicyclic polyhydric alcohols such as 1,6-hexanediol as raw materials.

[0077] Examples of urethane polyols include those having urethane bonds in the polymer produced by the polyaddition reaction of aromatic, aliphatic, or alicyclic diisocyanates with active hydrogen compounds, and having hydroxyl groups on the polymer side chains or terminals.

[0078] Examples of polyol components other than those mentioned above include polybutadiene polyol, modified polyol of polyhydric alcohol, and hydrogenated products thereof.

[0079] Examples of modified polyols of polyhydric alcohols include those obtained by modifying raw material polyhydric alcohols by reacting them with alkylene oxides. Examples of polyhydric alcohols include trihydric alcohols such as glycerin and trimethylolpropane; tetrahydric to octahydric alcohols such as pentaerythritol, sorbitol, mannitol, sorbitan, diglycerin, and dipentaerythritol, as well as sucrose, glucose, mannose, fructose, methyl glucoside, and derivatives thereof; phenol polybutadiene polyols such as phenol, phloroglucin, cresol, pyrogallol, catechol, hydroquinone, bisphenol A, bisphenol F, bisphenol S, 1-hydroxynaphthalene, 1,3,6,8-tetrahydroxynaphthalene, anthrol, 1,4,5,8-tetrahydroxyanthracene, and 1-hydroxypyrene; castor oil polyols; polyfunctional polyols (e.g., having 2 to 100 functional groups) such as (co)polymers of hydroxyalkyl (meth)acrylates and polyvinyl alcohol; and condensates of phenol and formaldehyde (novolaks).

[0080] The method for modifying the polyhydric alcohol is not particularly limited, but a method of adding alkylene oxide (hereinafter abbreviated as AO) is preferably used. Examples of AO include AOs having 2 to 6 carbon atoms, such as ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), 1,3-propylene oxide, 1,2-butylene oxide, and 1,4-butylene oxide. Among these, from the viewpoints of properties and reactivity, PO, EO, and 1,2-butylene oxide are preferred, and PO and EO are more preferred. When two or more AOs are used (for example, PO and EO), the addition method may be block addition or random addition, or a combination of these.

[0081] Among these, it is preferable to use polycarbonate polyol as the polyol component of the present invention from the viewpoint of durability.Furthermore, in consideration of the impact on the environment, it is also preferable to use sebacic acid polyol obtained from plant-derived sebacic acid or castor oil polyol derived from castor oil.

[0082] The content of the polyol component is preferably 35 parts by mass or more, more preferably 40 parts by mass or more, and particularly preferably 45 parts by mass or more, per 100 parts by mass of the polyurethane resin raw material components of the present invention, and is preferably 80 parts by mass or less, more preferably 75 parts by mass or less, and particularly preferably 70 parts by mass or less.

[0083] The content of the polyol component is preferably 30 parts by mass or more, more preferably 35 parts by mass or more, and particularly preferably 40 parts by mass or more, relative to 100 parts by mass of the polyurethane resin composition of the present invention, and is preferably 70 parts by mass or less, more preferably 65 parts by mass or less, and particularly preferably 60 parts by mass or less.

[0084] (3) Other Raw Material Components In the present invention, in addition to the polyisocyanate component and polyol component described above, the raw material components for the polyurethane resin may contain, as necessary, a crosslinking agent, a chain extender, a curing accelerator (catalyst component), an organic solvent, etc. In addition, foaming agents, antifoaming agents, thickeners, surface conditioners, surfactants, fillers, weather resistance improvers, UV absorbers, water, dispersants, color pigments, pH adjusters, etc. may also be contained.

[0085] The chain extender is not particularly limited, but generally a diol with a relatively low molecular weight is used. Examples include petroleum-derived diols such as ethylene glycol, diethylene glycol, propanediol, butanediol, hexanediol, and PEG, and plant-derived diols such as 1,3-propanediol and 1,2-hexanediol. These diols may be used alone, or two or more may be used in combination as needed. Diamines and the like can also be used as needed. The amount of chain extender used is not particularly limited, but is generally about 1 to 5 parts by mass per 100 parts by mass of the polyurethane resin composition of the present invention.

[0086] A curing accelerator (catalyst component) can also be used. Specific examples include metal catalysts such as titanium diisopropoxybis(ethylacetoacetate), amine catalysts, and DBU catalysts. The amount of the curing accelerator used is not particularly limited, but is generally about 0.01 to 1 part by mass per 100 parts by mass of the flame-retardant polyurethane resin composition of the present invention.

[0087] The organic solvent is not particularly limited, but examples thereof include polar solvents inactive to isocyanate groups, such as dimethylformamide (DMF) and dimethyl sulfoxide (DMSO), and organic solvents such as methyl ethyl ketone (MEK), toluene, and xylene.

[0088] (4) Reaction Product The reaction product contained in the flame-retardant polyurethane resin composition of the present invention is a polyurethane resin obtained by molding, as necessary, raw material components for a flame-retardant polyurethane resin, including the polyisocyanate component, the polyol component, and other raw material components used as needed, and then subjecting the molded product to treatments such as drying, heating, and curing.

[0089] The molar ratio of the polyisocyanate component to the polyol component is preferably polyisocyanate component / polyol component=0.6 / 1 to 1.8 / 1. If either the polyisocyanate component or the polyol component is too much, it becomes difficult to obtain a resin layer that exhibits durability and toughness.

[0090] The number average molecular weight of the polyurethane resin thus obtained is preferably 2000 or more, more preferably 2500 or more. There is no particular upper limit to the number average molecular weight, but it is usually 200,000,000 or less, preferably 100,000,000 or less. When the number average molecular weight of the polyurethane resin is within the above range, a resin suitable for forming a resin layer can be obtained.

[0091] (5) Flame Retardant The flame-retardant polyurethane resin composition of the present invention contains at least the above-mentioned reaction product (polyurethane resin) and a flame retardant consisting of the organophosphorus compound of the present invention. The content of the organophosphorus compound is not particularly limited, but is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, and most preferably 20% by mass or more, based on the total amount of the flame-retardant polyurethane resin composition (solid content) of the present invention. The upper limit is not particularly limited, but is preferably 40% by mass or less, more preferably 30% by mass or less, and particularly preferably 25% by mass or less.

[0092] In addition to the organic phosphorus compound of the present invention, a known flame retardant can also be used in combination. For example, organic phosphorus compounds include phosphate esters and salts thereof other than the organic phosphorus compound of the present invention, phosphite esters and salts thereof, phosphonic acid and derivatives thereof (including salts), phosphinic acid and derivatives thereof (including salts), phosphine, phosphine oxide, biphosphine, phosphonium salts, and phosphazene. Inorganic phosphorus compounds include phosphate salts, such as ammonium polyphosphate. In addition to the above-mentioned compounds, simple red phosphorus may also be used.

[0093] Examples of flame retardants other than phosphorus compounds include melamine compounds such as melamine cyanurate and melamine, metal hydrates such as aluminum hydroxide and magnesium hydroxide, and antimony compounds such as antimony trioxide and antimony pentoxide. Among these, phosphinates are preferred because they have good flame retardancy and little effect on physical properties.

[0094] When a flame retardant other than the organophosphorus compound of the present invention is used in combination, the proportion thereof is not particularly limited, but is preferably 10 to 50% by mass, more preferably 20 to 40% by mass, based on the total amount of flame retardants.

[0095] In the flame retardant of the present invention, phytic acid, which is effective in providing flame retardancy, decomposes at a temperature (second-stage decomposition temperature) close to or higher than the thermal decomposition temperature of the resin used. Therefore, the flame retardancy is not impaired by decomposition before the resin is thermally decomposed, and the flame retardancy can be exhibited extremely efficiently, allowing the amount of flame retardant added to the resin to be kept low.

[0096] The flame-retardant polyurethane resin composition of the present invention can reduce the amount of flame retardant by using the organophosphorus compound of the present invention containing a phytic acid structure that is decomposable at a decomposition temperature of 200 to 400° C., which is close to the thermal decomposition temperature (290° C.) of polyurethane resin. Specifically, the amount of flame retardant consisting of an organophosphorus compound in the flame-retardant polyurethane resin composition of the present invention can be reduced to 25% by weight or less, more preferably 10% by weight or less.

[0097] (6) Other Additives The flame-retardant polyurethane resin composition of the present invention may contain, as necessary, foaming agents, antifoaming agents, thickeners, surface conditioners, surfactants, fillers, weather resistance improvers, ultraviolet absorbers, organic solvents, water, dispersants, color pigments, pH adjusters, and the like, within limits that do not impair the physical properties of the polyurethane resin obtained by curing.

[0098] In addition, optional components such as urethanization catalysts, silane coupling agents, thixotropy-imparting agents, tackifiers, waxes, heat stabilizers, light resistance stabilizers, fluorescent brighteners, thermoplastic resins, thermosetting resins, dyes, pigments, conductivity-imparting agents, antistatic agents, moisture permeability improvers, water repellents, oil repellents, hollow foams, crystal water-containing compounds, water absorbents, moisture absorbents, deodorizers, foam stabilizers, antifungal agents, preservatives, anti-algae agents, pigment dispersants, inert gases, antiblocking agents, and hydrolysis inhibitors can also be used as needed. These additives can be used alone or in combination of two or more.

[0099] (7) Flame-retardant polyurethane resin composition The flame-retardant polyurethane resin composition of the present invention can be obtained by molding, if necessary, a flame-retardant polyurethane resin raw material blend containing the above-mentioned flame-retardant polyurethane resin raw material components, a flame retardant, and other additives, followed by heat curing. The heat curing conditions are preferably a temperature of 80 to 140°C and a time of 1 to 10 minutes.

[0100] If necessary, a step of removing liquid components such as organic solvents (drying step) can be included. For example, the raw materials for the flame-retardant polyurethane resin, the flame retardant and other additives can be blended, followed by molding, drying, and heat curing. Drying and heat curing can be performed in a single step or separately.

[0101] For example, when a layer made of a flame-retardant polyurethane resin composition is formed on a support (such as a base fabric) of the synthetic leather of the present invention as described below, a raw material blend for the flame-retardant polyurethane resin can be applied to the support, and then the mixture can be subjected to treatments such as drying and heat curing.

[0102] Alternatively, the polyisocyanate component and a part or all of the polyol component may be reacted in advance, preferably in the presence of a chain extender, and then a flame retardant and other additives may be mixed in. In this case, an organic solvent may also be added.

[0103] When applying the raw material composition for a flame-retardant polyurethane resin to a substrate, it is preferable to adjust the formulation so that it has a viscosity that can be applied without the addition of a solvent, although if necessary, the addition of an organic solvent to achieve a viscosity suitable for application is not excluded.

[0104] 4. Synthetic Leather The synthetic leather of the present invention includes at least a support (base fabric) and a surface layer. The synthetic leather of the present invention also includes so-called artificial leather. The synthetic leather of the present invention has high flame retardancy and can be added in small amounts, which has the advantage of not impairing the flexibility of the resin. Therefore, as a synthetic leather that combines flexibility and flame retardancy, it can be suitably used as a material for automobile seats, etc.

[0105] (1) Support The support (base fabric) used in the synthetic leather of the present invention can be any conventionally known synthetic leather substrate, and is not particularly limited. Examples include fibrous fabrics such as woven or knitted fabrics made of twill or plain weave, raised fabrics obtained by mechanically raising the cotton fabric of such woven fabrics, rayon fabric, nylon fabric, polyester fabric, Kevlar fabric, nonwoven fabrics (polyester, nylon, various latexes, etc.), various synthetic resin films and sheets, natural leather, etc. These may be selected appropriately depending on the purpose. Preferred examples include fibrous fabrics such as woven fabrics, knitted fabrics, and nonwoven fabrics.

[0106] The thickness of the support can be appropriately set taking into consideration the material, structure, texture of the resulting synthetic leather, and application, but is preferably 100 to 2000 μm, and particularly preferably 200 to 1000 μm.

[0107] (2) Surface Layer The synthetic leather of the present invention has a surface layer containing the flame-retardant polyurethane resin composition on at least one surface of a support. The surface layer may be either a porous layer or a non-porous layer.

[0108] The thickness of the surface layer can be appropriately set taking into consideration the texture and use of the resulting synthetic leather, the material and shape of the support, etc., but is preferably 5 to 300 μm.

[0109] In the present invention, the surface layer may be colored, gloss adjusted, or patterned with an uneven surface, for the purpose of improving the surface strength and design of the synthetic leather. Furthermore, the synthetic leather may be configured with two or more layers, if necessary. When the synthetic leather is configured with two or more layers, examples of the layer other than the layer made of the flame-retardant polyurethane resin composition of the present invention include a heat-insulating layer and a foam layer.

[0110] (3) Method for Producing Synthetic Leather The synthetic leather of the present invention is produced by a method including the steps of laminating the above-mentioned raw material blend for a flame-retardant polyurethane resin, which is capable of forming the flame-retardant polyurethane resin composition of the present invention, on a support and heat-treating the resulting laminate to form a surface layer.

[0111] The surface layer can be formed, for example, by applying a raw material composition for a flame-retardant polyurethane resin to at least one surface of a support using a coating method. Examples of coating methods include coating the raw material composition for a flame-retardant polyurethane resin directly onto fabric using a knife coater, comma coater, roll coater, die coater, or lip coater. The thickness of the applied raw material composition for a flame-retardant polyurethane resin is not particularly limited, but is preferably 5 to 300 μm.

[0112] It is preferable to adjust the formulation of the raw material compound for the flame-retardant polyurethane resin so that it has a viscosity that can be applied without the addition of a solvent, but if necessary to adjust the viscosity, a solvent can be added. Examples of solvents include known organic solvents such as DMF, DMSO, MEK, toluene, and xylene. In this case, it is preferable to use a solution in which the solid content is dispersed at a concentration of about 60 to 100 parts by mass.

[0113] After the coating process, the formed coating layer is dried and heat-treated to heat-cure the raw material blend for the flame-retardant polyurethane resin, forming a layer made of a flame-retardant polyurethane resin composition. The drying and heat-cure can be performed in one step or in separate steps. For example, after forming the coating layer, it is preferable to perform the treatment at a temperature of 80 to 140°C for 1 to 10 minutes.

[0114] Alternatively, the flame-retardant polyurethane resin may be produced by a dipping method in which a support is impregnated with the raw material blend for the flame-retardant polyurethane resin.

[0115] Furthermore, the flame-retardant polyurethane resin may also be produced by a lamination method in which a separately formed surface layer is laminated to a support, for example, by forming a surface layer by coating the raw material formulation for a flame-retardant polyurethane resin on a releasable substrate, laminating the surface layer to a support, and then peeling off the releasable substrate.

[0116] Examples of bonding methods include a method using an adhesive or the like, in which the raw material composition for a flame-retardant polyurethane resin of the present invention is semi-cured by heating to leave it adhesive, and then bonded to a support, and the raw material composition for a flame-retardant polyurethane resin is then heated again to fully cure it.

[0117] Coating methods include known methods such as comma coating, knife coating, roll coating, gravure coating, die coating, and spray coating. After the film is formed, it is appropriately dried to form a surface layer. A fabric is directly pressed onto this surface layer, or an adhesive is applied by a known method, and then the surface layer is applied and pressed onto the support. The surface layer is then heat-cured by heat treatment (drying or heating), and then peeled off from the releasable substrate to obtain synthetic leather.

[0118] The pressure bonding conditions are preferably a temperature of 20 to 140°C, a pressure of 0.1 to 10 MPa, and a time of 0.0005 to 3 minutes. The heat treatment conditions are preferably a temperature of 80 to 140°C, and a time of 1 to 10 minutes.

[0119] When the surface layer is bonded to the support via an adhesive, examples of the adhesive that can be used include the flame-retardant polyurethane resin composition described above, as well as conventional adhesives based on polyurethane resins, acrylic resins, epoxy resins, etc., made from petroleum-based raw materials. The adhesive may be applied to either the surface layer side or the support side.

[0120] The releasable substrate is not particularly limited, and examples thereof include a film made of a resin (such as an olefin resin or a silicone resin; hereinafter referred to as a release agent) that has releasability against a polyurethane resin, and release paper, release cloth, or release film in which a release layer made of a release agent is laminated on a substrate such as paper, cloth, or film.

[0121] The releasable substrate may have an uneven pattern. By using such a releasable substrate, a resin film having an uneven pattern on its surface can be formed, which prevents blocking between film surfaces and allows the production of synthetic leather that feels good to the touch.

[0122] Among the above methods, the lamination method is preferably used in terms of the physical properties and texture of the resulting synthetic leather, but the present invention is not limited to these methods.

[0123] The synthetic leather of the present invention as described above is suitable for shoes, clothing, bags, furniture, vehicle interior materials (for example, instrument panels, doors, consoles, seats), etc.

[0124] The synthetic leather obtained in this manner can be subjected to further post-processing such as surface treatment and kneading, as necessary. In addition to the support and surface layer described above, an adhesive layer, a surface protective layer, etc. can also be provided. The adhesive layer is provided between the support and the surface layer, etc. The surface protective layer can be provided on the outside of the surface layer. Examples of the surface protective layer include a layer formed from a known polyurethane resin.

[0125] For example, a polyurethane resin to be used as a surface protective layer (outermost layer) is applied to a releasable substrate and dried, and the raw material composition for a flame-retardant polyurethane resin of the present invention is applied thereon, and the layer made of the flame-retardant polyurethane resin composition is semi-cured by heating to make it sticky, and then the layer made of the raw material composition for a flame-retardant polyurethane resin is laminated to a substrate, and the layer made of the raw material composition for a flame-retardant polyurethane resin is heat-treated to fully cure it, thereby obtaining synthetic leather having a surface protective layer as the outermost layer in addition to a substrate and a skin layer.

[0126] The flame retardancy of the coating forming the surface layer made of the flame-retardant polyurethane resin composition preferably has a maximum burning rate of 80 mm / min or less, as measured in accordance with the test method of U.S. automobile safety standard FMVSS 302. By providing a surface layer whose physical properties satisfy the above ranges, synthetic leather with high flame retardancy can be obtained.

[0127] The flame retardancy of synthetic leather formed from a surface layer made of the flame-retardant polyurethane resin composition and a support is preferably such that, like the flame retardancy of the coating, the maximum burning rate is 80 mm / min or less as measured in accordance with the test method of U.S. automobile safety standard FMVSS 302. Synthetic leather whose various physical properties satisfy the above ranges has high flame retardancy.

[0128] The present invention will be described below with reference to examples, but the present invention is not limited to these examples. Evaluations in the examples were carried out according to the following methods.

[0129] [Burning Rate] Evaluation was performed in accordance with the test method of the US Automobile Safety Standard FMVSS 302. A test piece (synthetic leather; thickness: 1000 μm) cut to a width of 100 mm and a length of 350 mm was ignited by applying a flame from a gas burner to the edge of the piece for 15 seconds, and the distance and time from when the ignited flame crossed a marked line 38 mm from the edge until it went out were measured to calculate the burning rate.

[0130] [Decomposition Temperature] A 2.5 mg powder sample of the amine phytate was subjected to simultaneous differential scanning calorimetry (TG-DSC) at a temperature range of 50 to 500°C and a heating rate of 10°C / min using a simultaneous thermal analyzer (trade name "NETZSCH STA 449 F3 Jupiter", manufactured by NETZSCH Japan Co., Ltd.). The mass loss initiation temperature was determined as the thermal decomposition temperature. The first-stage decomposition temperature was the decomposition initiation temperature, and the second-stage decomposition temperature was the extrapolated decomposition initiation temperature.

[0131] [Water absorption and deliquescence] 1 g of powder sample of amine phytate was dried under reduced pressure (vacuum degree: 0.1 Pa) at 40°C for 24 hours, and then left in a thermo-hygrostat at 25°C and 40% RH. After 24 hours, the weight was measured and the weight change was recorded as the amount of water absorption. After the weight measurement, the sample was touched with a hand to check whether it was sticky or not, which was used to evaluate deliquescence.

[0132] Example 1 Production of Phytic Acid Amine Salt An ethanol solution of 1,10-decanediamine (concentration 7% by mass, diamine 3 equivalents) was added dropwise to an aqueous phytic acid solution (concentration 50% by mass, phytic acid 1 equivalent). The resulting white precipitate was collected, purified by washing with ethanol (unreacted diamine was removed), and then vacuum dried to obtain phytic acid amine salt.

[0133] Furthermore, the raw material diamine and the synthesized amine salt of phytic acid were analyzed by solid-state high-resolution NMR measurement (15N CP / MAS NMR). As a result, in the raw material 1,10-decanediamine alone, a peak derived from the nitrogen atom of the diamine was detected at 33.823 ppm, but in the synthesized amine salt of phytic acid, the peak derived from 1,10-decanediamine disappeared and a new peak was detected at 39.043 ppm.

[0134] These results suggest that no free amino groups are present and that an amine salt has been formed. It also suggests that this product is composed of two molecules of phytic acid linked via one molecule of diamine (a 1:2 adduct structure of diamine and phytic acid). The results are shown in Figure 1. In Figure 1, the upper (solid line) shows the measurement results for the raw material 1,10-decanediamine alone, and the lower (dotted line) shows the measurement results for the synthesized phytic acid amine salt.

[0135] The decomposition temperatures of the resulting amine salt of phytic acid were measured and found to be 255° C. and 390° C. The results of DSC measurement of the decomposition temperatures are shown in FIG.

[0136] When gas generation during decomposition was monitored, the generation of diamine was detected around 250°C, but no phosphorus was detected, while the generation of phosphorus was detected around 390°C. From this, it is believed that the bond between phytic acid and diamine was broken around 250°C, causing the 1:2 adduct structure to decompose, and that the decomposition of phytic acid occurred around 390°C. The water absorption and deliquescence of the obtained amine salt of phytic acid were evaluated. The results are shown in Table 1.

[0137] [Preparation of Synthetic Leather] 20.2 parts by mass of the phytic acid amine salt obtained above as a flame retardant was blended with 100 parts by mass of a polycarbonate-based polyurethane resin (trade name "CRISBON TA-205", solid content 70% by mass, manufactured by DIC Corporation) and stirred to obtain a flame-retardant polyurethane blend liquid.

[0138] On the other hand, 100 parts by mass of a polycarbonate-based polyurethane resin (trade name "CRISBON NY-328", solid content 20% by mass, manufactured by DIC Corporation) was applied to a release paper so as to give a wet coating thickness of 200 μm, and the applied resin was heat-treated in a dryer at 100°C for 2 minutes to dry and solidify, thereby forming a surface layer having a thickness of 40 μm.

[0139] Next, the flame-retardant polyurethane liquid mixture obtained above was applied onto the surface layer so as to give a wet coating thickness of 200 μm, and then pre-dried in a dryer at 130° C. for 3 minutes, and then overlaid with a polyester tricot fabric and subjected to a pressure of 4 kgf / cm ２ (39.2 N / cm ２ The resulting synthetic leather was subjected to a flame-retardant polyurethane resin composition. The resulting synthetic leather was evaluated for burning rate.

[0140] The resulting synthetic leather had a flame-retardant polyurethane resin composition content of 22.4% by mass. The flame-retardant content was calculated as the proportion of flame retardant in the flame-retardant polyurethane resin composition after drying the flame-retardant polyurethane liquid blend (solid content 70% by mass) [flame retardant / (resin solid content + flame retardant)]. The results are shown in Table 1. The resulting synthetic leather had a thickness of 850 μm, of which the layer made of the flame-retardant polyurethane resin composition had a thickness of 160 μm.

[0141] Example 2 A polyurethane resin film was obtained in the same manner as in Example 1, except that an amine salt of phytic acid was prepared using 1,12-dodecanediamine instead of 1,10-decanediamine and used as a flame retardant. The results are shown in Table 1. The decomposition temperature measurement results of the obtained amine salt of phytic acid are shown in Figure 3.

[0142] Example 3 Synthetic leather was obtained in the same manner as in Example 1, except that an amine salt of phytic acid was prepared using ethylenediamine instead of 1,10-decanediamine and used as a flame retardant. The results are shown in Table 1. The decomposition temperature of the obtained amine salt of phytic acid is measured and the results are shown in Figure 4.

[0143] Example 4 Synthetic leather was obtained in the same manner as in Example 1, except that an amine salt of phytic acid was prepared using 2-methyl-1,5-pentanediamine instead of 1,10-decanediamine and used as a flame retardant. The results are shown in Table 1. The decomposition temperature of the obtained amine salt of phytic acid is measured and the results are shown in Figure 5.

[0144] Example 5 Synthetic leather was obtained in the same manner as in Example 1, except that 7.8 parts by mass of amine phytic acid salt was added as a flame retardant in the production of the flame-retardant polyurethane resin composition. The results are shown in Table 1.

[0145] Example 6 Synthetic leather was obtained in the same manner as in Example 1, except that 3.7 parts by mass of amine phytic acid salt was added as a flame retardant in the production of the flame-retardant polyurethane resin composition. The results are shown in Table 1.

[0146] Comparative Example 1 Synthetic leather was obtained in the same manner as in Example 1, except that phytic acid amine salt was prepared using "JEFFAMINE D-230" (polyoxypropylene diamine; manufactured by HUNTSMAN) instead of 1,10-decanediamine and used as a flame retardant. The obtained phytic acid amine salt easily deliquesced and was difficult to disperse in polyurethane resin. The results are shown in Table 1. The decomposition temperature measurement results of the obtained phytic acid amine salt are shown in Figure 6.

[0147] Comparative Example 2 Synthetic leather was obtained in the same manner as in Example 1, except that an amine salt of phytic acid was prepared using dodecylamine (aliphatic monoamine) instead of 1,10-decanediamine and used as a flame retardant. The results are shown in Table 1. The results of measuring the decomposition temperature of the obtained amine salt of phytic acid are shown in Figure 7. As is clear from Figure 7, the amine salt of phytic acid in Comparative Example 2 has only one decomposition temperature at 220°C.

[0148]

[0149] The organophosphorus compound of the present invention has low water absorption and a high decomposition temperature. Therefore, it can be used as a flame retardant that does not decompose at the thermal decomposition temperature of resins and efficiently exhibits flame retardant effects. Furthermore, since it is made from plant-derived phytic acid, by forming a salt with plant-derived polyamine, the biomass ratio of the flame retardant itself can be further increased.

[0150] By blending this with a biomass-polyurethane resin, a flame-retardant polyurethane resin composition with an extremely high biomass ratio and synthetic leather using the same can be obtained. The synthetic leather of the present invention can be used in a variety of fields, such as clothing, bags, shoes, and vehicle interior materials, and is suitable for use in vehicle interior materials, including automobile seats, ceiling materials, dashboards, door linings, and steering wheels.

Claims

1. An organophosphorus compound consisting of a salt of a chain aliphatic polyamine and phytic acid.

2. The aliphatic polyamine is R—(NH ２ 2. The organic phosphorus compound according to claim 1, wherein R is a chain aliphatic hydrocarbon group having 2 to 12 carbon atoms which may have a branched structure, and X is an integer of 2 to 4.

3. The organophosphorus compound according to claim 1, wherein the chain aliphatic polyamine is a straight-chain aliphatic diamine having 2 to 12 carbon atoms.

4. The organophosphorus compound according to claim 1, which comprises a structure in which at least two structural units derived from phytic acid are crosslinked by a structural unit derived from a linear aliphatic polyamine.

5. The organophosphorus compound according to claim 1, wherein the salt has a structure in which structural units derived from a chain aliphatic polyamine and structural units derived from phytic acid are present in a ratio of 1:1 to 8:1 (equivalent ratio).

6. The organophosphorus compound according to claim 1, wherein the salt is a salt prepared by mixing a chain aliphatic polyamine and phytic acid in a molar ratio of 1-1:5-1.

7. The organophosphorus compound according to claim 1, which has at least two decomposition temperatures, at least one of which is in the range of 200 to 400°C.

8. A flame retardant comprising the organophosphorus compound according to any one of claims 1 to 7.

9. A flame-retardant polyurethane resin composition containing the flame retardant according to claim 8.

10. A flame-retardant polyurethane resin composition according to claim 9, wherein the content of the flame retardant is 25 mass % or less based on the total amount of the flame-retardant polyurethane resin composition.

11. Synthetic leather made using the flame-retardant polyurethane resin composition according to claim 9.

Images