Plasticizer, thermoplastic polyurethane resin composition comprising said plasticizer, and molded article of same

Abstract

The present invention provides a plasticizer which reduces discoloration and odors in an obtained molded article. Specifically, provided is a plasticizer that is a diester for which glycol and benzoic acid are reaction starting materials, or a polyester for which glycol, dicarboxylic acid, and benzoic acid are reaction starting materials, wherein the content of components other than benzoic acid which are contained in the benzoic acid is not more than 1.0 mass%.

Description

Plasticizer, thermoplastic polyurethane resin composition containing said plasticizer, and molded article thereof

[0001] The present invention relates to a plasticizer, a thermoplastic polyurethane resin composition containing the plasticizer, and a molded article thereof.

[0002] Plasticizers are used when molding polyvinyl chloride resin (PVC), thermoplastic polyurethane resin (TPU), acrylic resin, polysulfide resin, nitrile rubber (NBR), acrylic rubber (ACM), triacetyl cellulose (TAC), diacetyl cellulose (DAC), polylactic acid (PLA), polybutylene succinate (PBS), polyhydroxyalkanoate (PHA), etc. The plasticizer is added for the purpose of lowering the processing temperature during molding and facilitating molding.

[0003] The performance required of a plasticizer includes various properties such as the number of colors, compatibility, and heat resistance when molded into a molded article, and plasticizers of ester compounds using benzoic acid as a reaction raw material are widely used (e.g., Patent Documents 1 to 3).

[0004] JP 2014-507514 A JP 2001-512150 A JP 2019-090022 A

[0005] Thermoplastic polyurethanes for use in the soles of sports shoes must be particularly flexible, and because sports shoes have become collectible in recent years, there is an increasing demand for aesthetic appearance.

[0006] The most common plasticizers for thermoplastic polyurethane resins are alkylene glycol dibenzoates such as dipropylene glycol dibenzoate (DPGDB) and polyesters end-capped with benzoic acid, but thermoplastic polyurethane resin molded articles obtained using these plasticizers often have a slightly yellowish tinge. Benzoate ester plasticizers also have the problem of having a distinctive odor.

[0007] The problem to be solved by the present invention is to provide a plasticizer that reduces the coloration and odor of the resulting molded article. Another problem to be solved by the present invention is to provide a molded article that reduces the coloration derived from the plasticizer.

[0008] As a result of intensive research to solve the above-mentioned problems, the present inventors have found that the above-mentioned problems can be solved by reducing the amounts of components other than benzoic acid, which are contained in trace amounts in benzoic acid, to a specific amount or less, and have completed the present invention.

[0009] That is, the present invention relates to the following plasticizers, etc.: 1. A plasticizer which is a diester made by reacting glycol and benzoic acid as reaction raw materials, or a polyester made by reacting glycol, dicarboxylic acid, and benzoic acid as reaction raw materials, wherein the content of components other than benzoic acid contained in the benzoic acid is 1.0 mass% or less. 2. The plasticizer according to 1, wherein the components other than benzoic acid are benzyl alcohol, benzaldehyde, biphenyl monocarboxylic acid, biphenyl dicarboxylic acid, and benzyl benzoate. 3. The plasticizer according to 1 or 2, wherein the glycol is an alkylene glycol having 2 to 18 carbon atoms and / or an oxyalkylene glycol having 2 to 18 carbon atoms. 4. The plasticizer according to any one of 1 to 3, wherein the glycol is one or more selected from the group consisting of 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol. 5. The plasticizer according to any one of 1 to 4, wherein the dicarboxylic acid is an aliphatic dicarboxylic acid having 2 to 12 carbon atoms. 6. The plasticizer according to any one of 1 to 5, wherein the dicarboxylic acid is one or more selected from the group consisting of succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, and hexahydrophthalic acid. 7. The plasticizer according to any one of 1 to 6, wherein the number average molecular weight of the polyester is in the range of 500 to 4,000. 8. 8. The plasticizer for thermoplastic polyurethanes according to any one of 1 to 7. 9. A thermoplastic polyurethane resin composition comprising a thermoplastic polyurethane resin and the plasticizer according to any one of 1 to 7. 10. A molded article of the thermoplastic polyurethane resin composition according to 9.

[0010] According to the present invention, a plasticizer can be provided that reduces the coloring and odor of the resulting molded article. According to the present invention, a molded article can be provided that reduces the coloring derived from the plasticizer.

[0011] An embodiment of the present invention will be described below. The present invention is not limited to the following embodiment, and can be carried out by making appropriate modifications within the scope that does not impair the effects of the present invention. The compounds in this specification may be derived from fossil resources or biological resources.

[0012] [Plasticizer] The plasticizer of the present invention is a diester produced by reacting glycol and benzoic acid as reaction raw materials, and / or a polyester produced by reacting glycol, a dicarboxylic acid, and benzoic acid as reaction raw materials, wherein the content of components other than benzoic acid contained in the benzoic acid is 1.0 mass% or less. Here, the term "reaction raw materials" means raw materials that constitute the diester and polyester of the present invention, and does not include solvents or catalysts that do not constitute polyesters.

[0013] Benzoic acid is generally produced industrially by methods such as treating benzoyl chloride with a hot solution of calcium hypochlorite, directly oxidizing toluene with manganese persulfate or manganese dioxide, or decarboxylating phthalic acid. In these industrial production methods, the high temperature reaction results in the reaction of benzoic acid with itself to produce biphenyl compounds (biphenyl monocarboxylic acid, biphenyl dicarboxylic acid, benzyl benzoate) as by-products, or insufficiently oxidized benzyl alcohol and benzaldehyde as by-products. In the present invention, a plasticizer with reduced odor can be obtained by limiting the content of components other than benzoic acid contained in benzoic acid to 1.0% by mass or less.

[0014] The plasticizer of the present invention is a diester produced by reacting glycol and benzoic acid as reaction raw materials, and / or a polyester produced by reacting glycol, dicarboxylic acid, and benzoic acid as reaction raw materials. Hereinafter, the diester used as the plasticizer of the present invention may be referred to as the "diester of the present invention," and the polyester used as the plasticizer of the present invention may be referred to as the "polyester of the present invention." The reaction raw materials for the diester of the present invention and the polyester of the present invention are described below.

[0015] The benzoic acid used as the reaction raw material is benzoic acid having a content of components other than benzoic acid of 1.0% by mass or less. The content of components other than benzoic acid contained in benzoic acid is preferably 0.7% by mass or less, 0.6% by mass or less, 0.5% by mass or less, and 0.3% by mass or less, in that order. The lower limit of the content of components other than benzoic acid contained in benzoic acid is not particularly limited, but is, for example, 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more. The lower limit may be set appropriately taking into account the cost allowable for treating benzoic acid, etc. The content of components other than benzoic acid in benzoic acid is confirmed by the method described in the Examples.

[0016] The above-mentioned "components other than benzoic acid" preferably means benzyl alcohol, benzaldehyde, biphenyl monocarboxylic acid, biphenyl dicarboxylic acid, and benzyl benzoate. That is, the total content of benzyl alcohol, benzaldehyde, biphenyl monocarboxylic acid, biphenyl dicarboxylic acid, and benzyl benzoate contained in benzoic acid is preferably 1.0 mass% or less.

[0017] The content of components other than benzoic acid in benzoic acid can be reduced to 1.0 mass % or less, for example, by subjecting benzoic acid to a falling film crystallization treatment and a reduced pressure distillation treatment in combination.

[0018] The falling film crystallization process is, for example, a process that includes the following steps (1) to (3): (1) Flowing molten benzoic acid into a temperature-controllable vertical tube, and cooling the inside of the tube to temporarily solidify the benzoic acid. (2) Heating the inside of the tube containing the solidified benzoic acid to approximately the melting point of benzoic acid (122.35°C) (for example, 120-125°C) to melt a portion of the solidified benzoic acid. (3) Collecting the molten benzoic acid. This molten benzoic acid is highly pure and does not contain biphenyl compounds (biphenyl monocarboxylic acid, biphenyl dicarboxylic acid, benzyl benzoate) that have a melting point higher than that of benzoic acid.

[0019] Benzoic acid also contains components such as benzyl alcohol and benzaldehyde, which have melting points similar to those of benzoic acid. These can be removed by distillation under reduced pressure, which can be carried out at least either before or after the falling film crystallization treatment.

[0020] The reaction raw material benzoic acid may be further substituted with an alkyl group having 1 to 6 carbon atoms.

[0021] The glycol used as the reaction raw material is preferably a glycol having 2 to 18 carbon atoms, more preferably an alkylene glycol having 2 to 18 carbon atoms or an oxyalkylene glycol having 2 to 18 carbon atoms.

[0022] Examples of the alkylene glycol having 2 to 18 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,5-pentanediol, 2,2-diethyl-1,3-propanediol (3,3-dimethyl-1,3-propanediol). 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like.

[0023] The alkylene glycol having 2 to 18 carbon atoms is preferably an alkylene glycol having 3 to 10 carbon atoms, more preferably an alkylene glycol having 3 to 6 carbon atoms, and even more preferably 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, or 1,6-hexanediol.

[0024] The oxyalkylene glycol having 2 to 18 carbon atoms is, for example, an alkylene glycol having 2 to 18 carbon atoms in which one of the carbon atoms has been replaced with an oxygen atom, and examples thereof include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol.

[0025] The oxyalkylene glycol having 2 to 18 carbon atoms is preferably an oxyalkylene glycol having 3 to 10 carbon atoms, more preferably an oxyalkylene glycol having 4 to 10 carbon atoms, and even more preferably diethylene glycol, triethylene glycol, or dipropylene glycol.

[0026] The glycols used as reaction raw materials may be used alone or in combination of two or more.

[0027] The dicarboxylic acid used as the reaction raw material is preferably an aliphatic dicarboxylic acid having 4 to 14 carbon atoms, more preferably an alkylenedicarboxylic acid having 4 to 14 carbon atoms, and even more preferably an alkylenedicarboxylic acid having 6 to 12 carbon atoms.

[0028] Examples of the alkylene dicarboxylic acid having 4 to 14 carbon atoms include succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid (dodecanedioic acid), cyclohexanedicarboxylic acid, hexahydrophthalic acid, etc. Among these, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid are more preferred, adipic acid and sebacic acid are even more preferred, and adipic acid is particularly preferred.

[0029] The dicarboxylic acids used as reaction raw materials may be used alone or in combination of two or more.

[0030] The plasticizer of the present invention uses glycol, dicarboxylic acid, and benzoic acid as reaction raw materials, but reaction raw materials other than these may also be used as long as the effect of the present invention is not impaired.

[0031] The reactant materials for the diester of the present invention preferably consist essentially of glycol and benzoic acid, more preferably consist only of glycol and benzoic acid. The reactant materials for the polyester of the present invention preferably consist essentially of glycol, dicarboxylic acid, and benzoic acid, more preferably consist only of glycol, dicarboxylic acid, and benzoic acid. Here, "consist essentially of" means that the reactant materials other than the above account for, for example, 5% by mass or less, 3% by mass or less, or 1% by mass or less.

[0032] The diester of the present invention is, for example, a compound represented by the following general formula (1), and the polyester of the present invention is, for example, a compound represented by the following general formula (2).

[0033] (In the general formulas (1) and (2), G is a glycol residue having 2 to 18 carbon atoms, A is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms, B is a benzoic acid residue, and p represents the number of repeating units.)

[0034] In the present invention, the term "carboxylic acid residue" refers to the organic group remaining after removing the carboxyl group from a carboxylic acid. The number of carbon atoms in the "carboxylic acid residue" does not include the carbon atoms in the carboxy group. In the present invention, the term "glycol residue" refers to the organic group remaining after removing the hydroxyl group from a glycol.

[0035] The glycol residue of G having 2 to 18 carbon atoms is a group corresponding to the glycol having 2 to 18 carbon atoms, which is a reaction raw material for the diester and polyester of the present invention. The aliphatic dicarboxylic acid residue of A having 2 to 12 carbon atoms is a group corresponding to the aliphatic dicarboxylic acid having 4 to 14 carbon atoms, which is a reaction raw material for the polyester of the present invention. The benzoic acid residue of B is a group corresponding to benzoic acid, which is a reaction raw material for the diester and polyester of the present invention.

[0036] The upper limit of p is not particularly limited, but is, for example, 30, and the average value of p is, for example, in the range of 3 to 20. The average value of p can be confirmed from the number average molecular weight of the polyester.

[0037] The number average molecular weight (Mn) of the polyester of the present invention is, for example, in the range of 500 to 6,000, preferably in the range of 500 to 5,000, more preferably in the range of 500 to 4,000, and even more preferably in the range of 500 to 3,000. The number average molecular weight (Mn) of the polyester of the present invention is confirmed by the method described in the examples.

[0038] The acid value of the polyester of the present invention is preferably 2.0 or less, more preferably 1.0 or less. The hydroxyl value of the polyester of the present invention is preferably 15 or less, more preferably 10 or less. The viscosity of the polyester of the present invention is preferably 7,000 mPa·s or less, more preferably 5,000 mPa·s or less. The acid value, hydroxyl value, and viscosity of the polyester of the present invention are confirmed by the methods described in the examples.

[0039] The plasticizer of the present invention may be at least one of the diester of the present invention and the polyester of the present invention, and may also be a plasticizer composition comprising both the diester of the present invention and the polyester of the present invention.

[0040] [Method for Producing Plasticizer] The diester of the present invention can be produced, for example, by reacting benzoic acid with glycol by a known method, and it is preferable to charge an excess amount of benzoic acid.

[0041] The polyester of the present invention can be produced by, for example, the following methods. Method 1: A method in which benzoic acid, a dicarboxylic acid, and a glycol are charged all at once and reacted. Method 2: A method in which a dicarboxylic acid and a glycol are reacted under conditions in which the equivalent of hydroxyl groups is greater than the equivalent of carboxyl groups to obtain a polyester having hydroxyl groups at the terminals of the main chain, and then the obtained polyester is reacted with benzoic acid.

[0042] In the case of the above-mentioned Method 1, by using an excess amount of glycol, a diester of benzoic acid and glycol can also be produced as a by-product, and a plasticizer composition comprising both the polyester of the present invention and the diester of the present invention can be obtained.

[0043] [Thermoplastic polyurethane resin composition] The thermoplastic polyurethane resin composition of the present invention comprises the plasticizer of the present invention and a thermoplastic polyurethane resin. The plasticizer of the present invention has high heat resistance, and a molded article obtained by hot molding the thermoplastic polyurethane resin composition of the present invention can be a molded article with reduced coloration derived from the plasticizer of the present invention.

[0044] The thermoplastic polyurethane resin may be a commercially available product or may be produced by a known method, for example, by reacting a polyisocyanate component with a polyol component.

[0045] Examples of the polyisocyanate component include linear or branched (acyclic) aliphatic diisocyanates such as 1,5-pentamethylene diisocyanate (PDI) and 1,6-hexamethylene diisocyanate (HDI); 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate; IPDI); 4,4'-, 2,4'-, or 2,2'-dicyclohexylmethane diisocyanate; cyclic aliphatic diisocyanates (alicyclic diisocyanates) such as 1,3- or 1,4-bis(isocyanatomethyl)cyclohexane; aromatic polyisocyanates such as 2,4- or 2,6-tolylene diisocyanate and 4,4'-, 2,4'-, or 2,2'-diphenylmethane diisocyanate; and araliphatic diisocyanates such as 1,3- or 1,4-xylylene diisocyanate.

[0046] The polyol component can be classified into, for example, low molecular weight polyols having a number average molecular weight of 60 or more but less than 400, and high molecular weight polyols having a number average molecular weight of 400 or more but less than 10,000.

[0047] Examples of low-molecular-weight polyols include linear diols such as 1,2-ethanediol (ethylene glycol), 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol; and branched diols such as 1,2-propanediol (propylene glycol), 1,2-butanediol, 1,3-butanediol, and 2,2-dimethyl-1,3-propanediol (neopentyl glycol).

[0048] Examples of high molecular weight polyols include polyether polyols such as polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene copolymers, and polytetramethylene ether glycol; polyester polyols such as polycaprolactone diol; and polycarbonate diols.

[0049] The polyisocyanate component and polyol component used in the production of the thermoplastic polyurethane resin may each be a single component or a combination of two or more components.

[0050] The content of the plasticizer of the present invention in the thermoplastic polyurethane resin composition of the present invention is preferably in the range of 10 to 100 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin, from the viewpoint of compatibility with the thermoplastic polyurethane resin, etc.

[0051] The thermoplastic polyurethane resin composition of the present invention only needs to contain a thermoplastic polyurethane resin and the plasticizer of the present invention, and may also contain other additives, etc. Examples of other additives include flame retardants, stabilizers, stabilizing aids, colorants, processing aids, fillers, antioxidants (antiaging agents), ultraviolet absorbers, light stabilizers, lubricants, antistatic agents, crosslinking aids, etc.

[0052] Examples of flame retardants include inorganic compounds such as aluminum hydroxide, antimony trioxide, magnesium hydroxide, and zinc borate; phosphorus compounds such as cresyl diphenyl phosphate, trischloroethyl phosphate, trischloropropyl phosphate, and trisdichloropropyl phosphate; and halogen compounds such as chlorinated paraffin. When a flame retardant is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 20 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0053] Examples of stabilizers include metal soap compounds such as lithium stearate, magnesium stearate, magnesium laurate, calcium ricinoleate, calcium stearate, barium laurate, barium ricinoleate, barium stearate, zinc octoate, zinc laurate, zinc ricinoleate, and zinc stearate; organotin compounds such as dimethyltin bis-2-ethylhexylthioglycolate, dibutyltin maleate, dibutyltin bisbutylmaleate, and dibutyltin dilaurate; antimony mercaptide compounds; and lanthanoid-containing compounds such as lanthanum oxide and lanthanum hydroxide. When a stabilizer is blended into the thermoplastic polyurethane resin composition, the blending amount is typically 0.1 to 20 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0054] Examples of stabilizing aids include phosphite compounds such as triphenyl phosphite, monooctyldiphenyl phosphite, tridecyl phosphite, etc.; beta-diketone compounds such as acetylacetone and benzoylacetone; polyol compounds such as glycerin, sorbitol, pentaerythritol, polyethylene glycol, etc.; perchlorate compounds such as barium perchlorate and sodium perchlorate; hydrotalcite compounds; zeolites, etc. When a stabilizing aid is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 20 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0055] Examples of colorants include carbon black, lead sulfide, white carbon, titanium white, lithopone, safflower, antimony sulfide, chrome yellow, chrome green, cobalt blue, molybdenum orange, etc. When a colorant is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 1 to 100 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0056] Examples of processing aids include liquid paraffin, polyethylene wax, stearic acid, stearamide, ethylene bisstearamide, butyl stearate, calcium stearate, etc. When a processing aid is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 20 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0057] Examples of fillers include metal oxides such as calcium carbonate, silica, alumina, clay, talc, diatomaceous earth, and ferrite; fibers and powders of glass, carbon, metal, and the like; glass spheres, graphite, aluminum hydroxide, barium sulfate, magnesium oxide, magnesium carbonate, magnesium silicate, and calcium silicate. When a filler is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 1 to 100 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0058] Examples of antioxidants include phenolic compounds such as 2,6-di-tert-butylphenol, tetrakis[methylene-3-(3,5-tert-butyl-4-hydroxyphenol)propionate]methane, and 2-hydroxy-4-methoxybenzophenone; sulfur compounds such as alkyl disulfides, thiodipropionic acid esters, and benzothiazole; phosphoric acid compounds such as trisnonylphenyl phosphite, diphenylisodecyl phosphite, triphenyl phosphite, and tris(2,4-di-tert-butylphenyl)phosphite; and organometallic compounds such as zinc dialkyldithiophosphate and zinc diaryldithiophosphate. When an antioxidant is incorporated into a thermoplastic polyurethane resin composition, the amount incorporated is typically 0.2 to 20 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0059] Examples of ultraviolet absorbers include salicylate-based compounds such as phenyl salicylate and p-tert-butylphenyl salicylate; benzophenone-based compounds such as 2-hydroxy-4-n-octoxybenzophenone and 2-hydroxy-4-n-methoxybenzophenone; benzotriazole-based compounds such as 5-methyl-1H-benzotriazole and 1-dioctylaminomethylbenzotriazole; and cyanoacrylate-based compounds. When an ultraviolet absorber is blended into a thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 10 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0060] Examples of the light stabilizer include hindered amine light stabilizers. Specific examples include bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidylsebacate (mixture), bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl)decanedioate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl]methyl]butylmalonate, bis(2,2,6,6-tetramethyl-4-piperidyl)decanedioate, bis(2,2,6,6-tetra ...sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)[[3,5-bis(1,1-dimethylethyl)- tetrakis(2,2,6,6-tetramethyl-4-piperidyl)ester and reaction products of 1,1-dimethylethyl hydroperoxide with octane, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine, ester mixture of 2,2,6,6-tetramethyl-4-piperidinol and higher fatty acids, tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethionyl) (2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, polycondensate of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, poly{(6-(1,1,3,3-tetramethylbutyl)amino-1,3,5-triazine-2,4-diyl){(2,2,6,6-tetramethyl-4-piperidyl)imino}hexamethylene{(2,2,6,6-tetramethyl-4-piperidyl)imino}}, dibutylamine Examples include a polycondensate of 1,3,5-triazine-N,N'-bis(2,2,6,6-tetramethyl-4-piperidyl-1,6-hexamethylenediamine and N-(2,2,6,6-tetramethyl-4-piperidyl)butylamine, and N,N',N'',N'''-tetrakis-(4,6-bis-(butyl-(N-methyl-2,2,6,6-tetramethylpiperidin-4-yl)amino)-triazin-2-yl)-4,7-diazadecane-1,10-diamine. When a light stabilizer is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 10 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0061] Examples of lubricants include silicone, liquid paraffin, paraffin wax, metal salts of fatty acids such as metal stearates and metal laurates, fatty acid amides, fatty acid waxes, higher fatty acid waxes, etc. When a lubricant is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 10 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0062] Examples of antistatic agents include anionic antistatic agents of the alkyl sulfonate type, alkyl ether carboxylic acid type, or dialkyl sulfosuccinate type; nonionic antistatic agents such as polyethylene glycol derivatives, sorbitan derivatives, and diethanolamine derivatives; cationic antistatic agents such as quaternary ammonium salts of the alkylamidoamine type, alkyldimethylbenzyl type, and alkylpyridinium type organic acid salts or hydrochlorides; and amphoteric antistatic agents such as alkylbetaine type and alkylimidazoline type. When an antistatic agent is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.1 to 10 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0063] Examples of crosslinking aids include polyfunctional monomers such as tetraethylene glycol dimethacrylate, divinylbenzene diallyl phthalate, triallyl isocyanurate, trimethylolpropane triallylate, tetramethylolmethane tetramethacrylate, and trimethoxyethoxyvinylsilane. When a crosslinking aid is blended into the thermoplastic polyurethane resin composition, the blending amount is usually 0.5 to 30 parts by mass per 100 parts by mass of the thermoplastic polyurethane resin.

[0064] The thermoplastic polyurethane resin composition of the present invention can be produced by a known method, for example, by mixing a thermoplastic polyurethane resin, the plasticizer of the present invention, and optional components (the other plasticizers and the other additives) using a kneader such as a blender, a planetary mixer, or a Banbury mixer.

[0065] The thermoplastic polyurethane resin molded article can be obtained by molding the thermoplastic polyurethane resin composition of the present invention by a known molding method such as vacuum molding, compression molding, extrusion molding, calendar molding, press molding, blow molding, or powder molding.

[0066] The method for obtaining a thermoplastic polyurethane resin molded product is not limited to the above. For example, a thermoplastic polyurethane resin molded product can also be obtained by introducing a polyisocyanate component and a polyol component, which are raw materials for a thermoplastic polyurethane resin, and the plasticizer of the present invention into an extruder, melt-kneading them and carrying out a polymerization reaction in the extruder, thereby simultaneously producing a thermoplastic polyurethane resin and molding the thermoplastic polyurethane resin.

[0067] Thermoplastic polyurethane resin molded articles can be used for belts, tubes, hoses, wire coating materials, cable coating materials, fire hoses, packing, bumpers, sheet materials, air mattresses, synthetic leather, shoe soles, watch bands, camera grips, smartphone cases, tablet cases, medical tubing, skis, rackets, etc.

[0068] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0069] The present invention will be specifically described below with reference to examples and comparative examples, but the present invention is not limited to the following examples.

[0070] In the examples, the acid value, viscosity, and freezing point were evaluated by the following methods. <Method for measuring acid value> Measured by a method conforming to JIS K0070-1992. <Method for measuring viscosity> Measured by a method conforming to JIS K6901-1986.

[0071] In the examples of the present application, the number average molecular weight of the polyester is a value calculated in terms of polystyrene based on GPC measurement, and the measurement conditions are as follows. [GPC measurement conditions] Measurement apparatus: High-speed GPC apparatus "HLC-8420GPC" manufactured by Tosoh Corporation Column: Two "TSKgel SuperMultiporeHZ-H" manufactured by Tosoh Corporation Detector: RI (differential refractometer) Data processing: "EcoSEC Data Analysis Version 1.07" manufactured by Tosoh Corporation Column temperature: 40°C Developing solvent: Tetrahydrofuran Flow rate: 0.35 mL / min Measurement sample: 20 mg of sample was dissolved in 10 ml of tetrahydrofuran, and the resulting solution was filtered through a microfilter to prepare a measurement sample. Sample injection volume: 20 μl Standard substance: "PStQuick MP-H" manufactured by Tosoh Corporation

[0072] (Synthesis Example 1: Synthesis of Ester Compound Plasticizer A1) 365 g (4.80 mol) of 1,2-propanediol, 976 g (8.00 mol) of benzoic acid A, and 0.402 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2-liter four-neck flask equipped with a thermometer, a stirrer, and a reflux condenser. The temperature was gradually increased to 230°C while stirring under a nitrogen stream, and heating was continued at 230°C until the acid value reached 4 or less, while water for purification was continuously removed. After the reaction, unreacted glycol was distilled off under reduced pressure at 230 to 200°C, yielding Ester Compound Plasticizer A1.

[0073] The benzoic acid A used in Synthesis Example 1 was benzoic acid that had been subjected to a falling film crystallization treatment and a reduced-pressure distillation treatment, and it was confirmed separately by gas chromatography that the total content of components other than benzoic acid, such as benzyl alcohol, benzaldehyde, biphenyl compounds, and benzyl benzoate, in the benzoic acid was 0.5% by mass.

[0074] The gas chromatography was carried out using a Shimadzu Corporation "GC-2030" under the following conditions: Column: Agilent Technologies Inc. capillary column DB-5 Detector: FID (flame ionization detector) Column temperature: 40 to 320°C Injection volume: 1 μL (tetrahydrofuran diluted solution)

[0075] Synthesis Example 2: Synthesis of Ester Compound Plasticizer A2 288 g (2.72 mol) of diethylene glycol, 158 g (2.08 mol) of 1,2-propanediol, 976 g (8.00 mol) of benzoic acid A, and 0.427 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2-liter four-neck flask equipped with a thermometer, a stirrer, and a reflux condenser. The temperature was gradually increased to 230°C while stirring under a nitrogen stream, and heating was continued at 230°C until the acid value of the reaction solution reached 4 or less, with the generated water being continuously removed. After the reaction, unreacted glycol in the reaction solution was distilled off under reduced pressure at 230 to 200°C to obtain Ester Compound Plasticizer A2.

[0076] Synthesis Example 3: Synthesis of Ester Compound Plasticizer A3 327 g (2.24 mol) of adipic acid (Asahi Kasei Chemicals Corporation), 401 g (5.28 mol) of 1,2-propylene glycol (Asahi Glass Co., Ltd.), 545 g (4.47 mol) of benzoic acid A, and 0.120 g of tetraisopropyl titanate as an esterification catalyst were charged into a 2-L four-neck flask equipped with a thermometer, a stirrer, and a reflux condenser, and the temperature was raised stepwise to 230°C while stirring under a nitrogen stream. Heating was continued at 230°C until the acid value reached 5 or less, and the generated water was continuously removed. After the reaction, unreacted 1,2-propylene glycol was distilled off under reduced pressure at 230 to 200°C to obtain 988 g of Ester Compound Plasticizer A3 (acid value 0.5, viscosity 672 mPa s (25°C)).

[0077] (Synthesis Comparative Example 1: Synthesis of Ester Compound Plasticizer B1) Ester compound plasticizer B1 was obtained in the same manner as in Synthesis Example 1, except that benzoic acid B was used instead of benzoic acid A. Benzoic acid B was commercially available benzoic acid (manufactured by WUHAN YOUJI INDUSTRIES CO., LTD.), and it was separately confirmed by gas chromatography in the same manner as in Synthesis Example 1 that the total content of components other than benzoic acid, such as benzyl alcohol, benzaldehyde, biphenyl compounds, and benzyl benzoate, in the benzoic acid was 1.5 mass%.

[0078] Comparative Synthesis Example 2: Synthesis of Ester Compound Plasticizer B2 Ester compound plasticizer B2 was obtained in the same manner as in Synthesis Example 1, except that benzoic acid B was used instead of benzoic acid A.

[0079] Comparative Synthesis Example 3: Synthesis of Ester Compound Plasticizer B3 Ester compound plasticizer B3 was obtained in the same manner as in Synthesis Example 1, except that benzoic acid B was used instead of benzoic acid A.

[0080] (Examples 1 to 6 and Comparative Examples 1 to 6: Evaluation of Plasticizers and Molded Articles) The plasticizers produced in the Synthesis Examples and Comparative Synthesis Examples were evaluated as follows. The results are shown in Tables 1 and 2.

[0081] The color number (Hazen unit color number, APHA) of the plasticizers prepared in the synthesis examples and comparative examples was evaluated in accordance with JIS K0071-1:2017. The results are shown in Table 1. A smaller color number indicates less coloration.

[0082] (Evaluation of plasticizer odor) 100 g of plasticizer was placed in a 225 ml glass bottle and left at room temperature for approximately 2 hours, after which the suction nozzle of a sensor (Shin Cosmos Electric Co., Ltd. Portable Odor Sensor XP-329) was inserted into an 8 mm hole in the inner lid to start measurement, and the value after 3 minutes was read and the plasticizer odor was evaluated according to the following evaluation criteria. The smaller the sensor value, the less odor there was. 1: Sensor value less than 100 2: Sensor value 100 or more but less than 300 3: Sensor value 300 or more but less than 500 4: Sensor value 500 or more

[0083] (Preparation of Thermoplastic Polyurethane (TPU) Resin Composition and Production of Molded Article) Two types of polyurethane resin compositions were prepared using the following two blending patterns: Blending pattern 1: 100 parts by mass of polyurethane resin (Pandex T-8180N (ether-based), manufactured by DIC Covestro Polymer Co., Ltd.), 20 parts by mass of plasticizer, and 0.5 parts by mass of lubricant (Licolub WE-4, manufactured by Clariant Chemicals Co., Ltd.) were mixed to prepare a polyurethane resin composition. Blending pattern 2: 100 parts by mass of polyurethane resin (Pandex T-1180N (ether-based), manufactured by DIC Covestro Polymer Co., Ltd.), 20 parts by mass of plasticizer, and 0.5 parts by mass of lubricant (Licolub WE-4, manufactured by Clariant Chemicals Co., Ltd.) were mixed to prepare a polyurethane resin composition.

[0084] The polyurethane resin composition prepared was kneaded for 5 minutes using two rolls heated to 140-150°C, and then the kneaded polyurethane resin composition was molded using a mold capable of producing a molded product with a thickness of 1.0 mm (a 1.0 mm-thick mold) and a press machine heated to 140-150°C to prepare a sheet with a thickness of 1.0 mm.

[0085] (Evaluation of Plasticizing Performance of Plasticizer) From the sheet obtained above, dumbbell-shaped No. 3 dumbbell test pieces were prepared in accordance with JIS K7311:1995. The 100% modulus (tensile stress at 100% elongation) and elongation at break of these test pieces were evaluated in accordance with JIS K7311:1995. Specifically, a tensile test was conducted using a 1.0 mm thick sheet under the following conditions to evaluate the 100% modulus and elongation at break. The results are shown in Table 1. The elongation at break was calculated as a percentage by subtracting the initial chuck distance of 20 mm from the chuck distance at which the 1.0 mm thick sheet broke by dividing the value by the chuck distance of 20 mm. Measuring equipment: Tensilon universal material testing machine (manufactured by Orientec Co., Ltd.) Sample shape: Dumbbell No. 3 Gauge distance: 20 mm Chuck distance: 60 mm Tensile speed: 200 mm / min Measurement atmosphere: Temperature 23°C, humidity 50%

[0086] A lower 100% modulus value indicates a higher effect of plasticizing the polyurethane resin, and a higher breaking elongation percentage indicates a higher effect of plasticizing the polyurethane resin.

[0087] (Evaluation of heat resistance of molded article) The sheet obtained above was cut into a sheet sample measuring 30 mm in length, 30 mm in width, and 1 mm in thickness, and the initial yellowness YI value (initial YI value) of the sheet sample was measured in accordance with JIS K7373:2006 using a color difference meter ("TZ-7700" manufactured by Nippon Denshoku Industries Co., Ltd.). After measuring the initial YI value, the sheet sample was heated at 120°C for 72 hours, and the post-heating yellowness YI value (post-heating YI value) of the sheet sample was measured again. The difference between the initial YI value and the post-heating YI value was taken as the ΔYI value. The ΔYI value is a numerical representation of the degree of yellowing, and a smaller value indicates less color change (yellowing).

[0088]

[0089]

[0090] The amounts of components other than benzoic acid differ by only about 1% by mass between benzoic acid A and benzoic acid B in the examples and comparative examples. However, the results in Tables 1 and 2 confirm that by reducing the amounts of components other than benzoic acid in benzoic acid, the odor of the plasticizer obtained using the benzoic acid can be significantly reduced, and the coloring due to the plasticizer in the molded article using the plasticizer can also be significantly reduced.

Claims

1. A plasticizer that is a diester made from glycol and benzoic acid as reaction raw materials, or a polyester made from glycol, a dicarboxylic acid, and benzoic acid as reaction raw materials, The plasticizer is a plasticizer in which the benzoic acid is treated by falling film crystallization and vacuum distillation, and the content of components other than benzoic acid contained in the benzoic acid is 1.0 mass% or less.

2. 2. The plasticizer according to claim 1, wherein the components other than benzoic acid are benzyl alcohol, benzaldehyde, biphenyl monocarboxylic acid, biphenyl dicarboxylic acid, and benzyl benzoate.

3. 2. The plasticizer according to claim 1, wherein the glycol is an alkylene glycol having 2 to 18 carbon atoms and / or an oxyalkylene glycol having 2 to 18 carbon atoms.

4. The plasticizer according to claim 1, wherein the glycol is at least one selected from the group consisting of 1,2-propanediol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, 2-methyl-1,3-propanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, diethylene glycol, and dipropylene glycol.

5. 2. The plasticizer according to claim 1, wherein the dicarboxylic acid is an aliphatic dicarboxylic acid having 2 to 12 carbon atoms.

6. 2. The plasticizer according to claim 1, wherein the dicarboxylic acid is at least one selected from the group consisting of succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, cyclohexanedicarboxylic acid, and hexahydrophthalic acid.

7. 2. The plasticizer according to claim 1, wherein the number average molecular weight of the polyester is in the range of 500 to 4,000.

8. The plasticizer according to claim 1, which is a plasticizer for thermoplastic polyurethanes.

9. A thermoplastic polyurethane resin composition comprising a thermoplastic polyurethane resin and the plasticizer of claim 1.

10. A molded article of the thermoplastic polyurethane resin composition according to claim 9.