Plasticizer, composition, and molded article

Abstract

The purpose of the present invention is to provide: a plasticizer that imparts excellent plasticity to a biodegradable resin; and a composition and a molded article that contain the plasticizer.　The present invention provides a plasticizer that contains a dibenzoate compound represented by general formula (1), has a hydroxyl value of 0.1-20 mgKOH / g, and is used in biodegradable resin. In the formula, R1 represents a C1-8 alkanediyl group, and n represents an integer of 1-8.　R1 preferably represents a C2-3 alkylene group, and n preferably represents an integer of 1-3.

Description

Plasticizers, compositions, and molded articles

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

[0002] In recent years, there has been a demand for biodegradable resins and molded articles made from them that decompose in natural environments such as soil and the ocean, and research into biodegradable resins such as aliphatic polyesters has been actively conducted. In particular, polylactic acid resins have high melting points, can be melt-molded, and have excellent transparency, so they are highly anticipated for use as packaging materials and molded articles that take advantage of their transparency.

[0003] However, polylactic acid resins are highly crystalline and have poor flexibility, making them unsuitable for applications requiring flexibility, such as films and packaging materials. Addition of a plasticizer is known as a method for improving flexibility. For example, Patent Document 1 describes a technique for blending a polypropylene glycol dibenzoate plasticizer with a lactic acid-based polymer. Patent Document 2 proposes a plasticizer for lactic acid-based polymers consisting of polyethylene glycol dibenzoate having a number-average molecular weight of 150 or more.

[0004] JP 2000-136300 A JP 2003-105182 A

[0005] However, as a result of investigations by the present inventors, it has been found that the plasticizers described in the above Patent Documents 1 and 2 have room for improvement in terms of plasticity.

[0006] An object of the present invention is to provide a plasticizer that imparts excellent plasticity to a biodegradable resin, and a composition and molded article containing the same.

[0007] As a result of further investigations, the present inventors discovered that a plasticizer containing polyalkylene glycol and having a hydroxyl value within a specific range imparts excellent plasticity to a biodegradable resin, leading to the completion of the present invention.

[0008] The present invention provides a plasticizer for biodegradable resins, which contains a dibenzoate compound represented by the following general formula (1), has a hydroxyl value of 0.1 to 20 mgKOH / g, and is suitable for use in biodegradable resins.

[0009] In the formula, R１ represents an alkanediyl group having 1 to 8 carbon atoms, and n represents an integer of 1 to 8.

[0010] The plasticizer of the present invention is a compound represented by the general formula (1) R １ Preferably, represents an alkylene group having 2 to 3 carbon atoms.

[0011] In the plasticizer of the present invention, n in general formula (1) preferably represents an integer of 1 to 3.

[0012] The present invention also provides a composition containing a biodegradable resin and the above plasticizer.

[0013] The composition of the present invention preferably contains 0.1 to 50 parts by mass of the plasticizer relative to 100 parts by mass of the biodegradable resin.

[0014] The present invention also provides a molded article obtained from the above composition.

[0015] According to the present invention, it is possible to provide a plasticizer that imparts excellent plasticity to a biodegradable resin, and a composition and a molded article containing the same.

[0016] The present invention relates to a plasticizer, a composition, and a molded article. The present invention will be described below based on preferred embodiments thereof.

[0017] <Plasticizer> The plasticizer of the present invention contains a dibenzoate compound represented by the following general formula (1).

[0018] In the formula, R １ represents an alkanediyl group having 1 to 8 carbon atoms, and n represents an integer of 1 to 8.

[0019] The plasticizer of the present invention preferably has a hydroxyl value within a specific range. From the viewpoint of plasticity, the hydroxyl value is preferably 0.1 mgKOH / g or more, more preferably 0.3 mgKOH / g or more, even more preferably 0.5 mgKOH / g or more, and particularly preferably 1 mgKOH / g or more. Furthermore, from the viewpoint of heat resistance and plasticity, the hydroxyl value is preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less, even more preferably 10 mgKOH / g or less, and particularly preferably 7 mgKOH / g or less. The hydroxyl value can be measured by the method described in JIS K 1557.

[0020] The plasticizer of the present invention has the effect of imparting excellent plasticity to biodegradable resins. The reason for this effect is not clear, but is presumed to be as follows.

[0021] Generally, plasticizers penetrate between resin molecules, weakening the intermolecular forces of the resin and facilitating the movement of each molecular chain, thereby lowering the resin's glass transition temperature and imparting plasticity to the resin. The plasticizer of the present invention has a polyoxyalkylene structure, which is the structure in parentheses of general formula (1), and has a hydroxyl value within a specific range, so that it has a moderate affinity for biodegradable resin molecules, making it easy to penetrate between resin molecules, and can appropriately suppress strong bonds such as hydrogen bonds that occur between hydroxyl groups derived from the plasticizer and atoms derived from the biodegradable resin, thereby imparting excellent plasticity to the resin. This effect is particularly exhibited in combination with structures characteristically contained in biodegradable resins, such as polyester structures and polyvinyl alcohol structures.

[0022] R in the above general formula (1) １Examples of the alkanediyl group having 1 to 8 carbon atoms represented by the formula (I) include alkylene groups such as methylene, ethylene, propylene, butylene, pentylene, hexylene, heptylene, and octylene; and alkylidene groups such as ethylidene, propylidene, butylidene, and hexylidene. The alkanediyl group may be linear or branched. The alkanediyl group may contain an isomer. Among these, from the viewpoints of heat resistance and plasticity, alkylene groups having 2 to 4 carbon atoms such as ethylene, propylene, and butylene are preferred, alkylene groups having 2 to 3 carbon atoms such as ethylene and propylene are more preferred, propylene is even more preferred, and 1,2-propylene is particularly preferred.

[0023] In the above general formula (1), n ​​is preferably an integer of 1 to 4, more preferably an integer of 1 to 3, even more preferably an integer of 2 or 3, and particularly preferably 2, from the viewpoints of heat resistance and plasticity.

[0024] Examples of the compound represented by the general formula (1) include ethylene glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol dibenzoate, polyethylene glycol dibenzoate, propylene glycol dibenzoate, dipropylene glycol dibenzoate, tripropylene glycol dibenzoate, polypropylene glycol dibenzoate, butylene glycol dibenzoate, dibutylene glycol dibenzoate, tributylene glycol dibenzoate, and neopentyl glycol dibenzoate. Among these, from the viewpoints of heat resistance and plasticity, ethylene glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol dibenzoate, propylene glycol dibenzoate, dipropylene glycol dibenzoate, and tripropylene glycol dibenzoate are preferred, ethylene glycol dibenzoate, diethylene glycol dibenzoate, propylene glycol dibenzoate, and dipropylene glycol dibenzoate are more preferred, diethylene glycol dibenzoate and dipropylene glycol dibenzoate are even more preferred, and dipropylene glycol dibenzoate is particularly preferred.

[0025] The content of the compound represented by the general formula (1) in the plasticizer of the present invention is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, even more preferably 90 parts by mass or more, and particularly preferably 95 parts by mass or more, per 100 parts by mass of the plasticizer, thereby enabling the plasticizing effect of the plasticizer to be sufficiently obtained.

[0026] The compound represented by the general formula (1) can be produced by a conventionally known production method. For example, benzoic acid or a benzoic acid derivative can be combined with a glycol corresponding to the structure in parentheses in the general formula (1) and reacted. Specifically, direct esterification of benzoic acid with glycol, transesterification of methyl benzoate with glycol, reaction of benzoic acid halide with glycol, etc. are possible. The compound represented by the general formula (1) obtained by the above method or the like may be further separated and purified, as necessary, by separation and purification means such as filtration, concentration, distillation, extraction, crystallization, recrystallization, adsorption, and column chromatography, or a combination of these means.

[0027] The plasticizer of the present invention is preferably used in a biodegradable resin, since the effect as a plasticizer can be easily obtained. Examples of the biodegradable resin include those exemplified as the biodegradable resin contained in the composition described below. Among them, it is preferable to use the plasticizer in a polylactic acid resin, since the effect of improving plasticity can be sufficiently obtained.

[0028] <Composition> The composition of the present invention contains a biodegradable resin and the plasticizer described above. Examples of the biodegradable resin include microbially produced resins, natural product resins, and chemically synthesized resins.

[0029] Examples of microbially produced resins include polyhydroxyalkanoates. Examples of natural product resins include cellulose derivatives and starch derivatives. Examples of chemically synthesized resins include polyester biodegradable resins such as polylactic acid resin, polybutylene succinate, polybutylene succinate adipate, polybutylene adipate terephthalate, polyethylene succinate, polyglycolic acid, polycaprolactone, and poly(3-hydroxybutyrate-co-hydroxyhexanoate), hydroxyl group-containing biodegradable resins such as polyvinyl alcohol, and partially acetylated cellulose resins. Among these, chemically synthesized resins are preferred, polyester biodegradable resins are more preferred, and polylactic acid resins are particularly preferred, in terms of being able to fully achieve the effect of improving plasticity.

[0030] The following describes the case where a polylactic acid resin is used as the biodegradable resin. Examples of the polylactic acid resin used in the present invention include polylactic acid homopolymers, polylactic acid copolymers, and blend polymers of polylactic acid homopolymers and polylactic acid copolymers.

[0031] The weight-average molecular weight (Mw) of the polylactic acid resin is preferably 50,000 to 500,000, and more preferably 100,000 to 250,000, as determined by gel permeation chromatography analysis in terms of polystyrene. This is because a weight-average molecular weight within the above range results in excellent physical properties and moldability. Specific examples of such polylactic acid include the "Ingeo" series manufactured by NatureWorks and the "Luminy" series manufactured by Total Corbion.

[0032] Furthermore, the molar ratio (L / D) of L-lactic acid units to D-lactic acid units in the polylactic acid resin is not particularly limited and can be selected from the range of 100 / 0 to 0 / 100. To obtain a polylactic acid resin composition with a high melting point, it is preferable that either the L-lactic acid units or the D-lactic acid units account for 75 mol% or more, and to obtain a polylactic acid resin composition with an even higher melting point, it is preferable that either the L-lactic acid units or the D-lactic acid units account for 90 mol% or more.

[0033] Furthermore, the polylactic acid resin may be a copolymer of lactic acid monomer or lactide with other copolymerizable components, such as dicarboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, lactonic acids, and various polyesters, polyethers, and polycarbonates containing these as constituent components, each having two or more ester bond-forming functional groups.

[0034] Examples of the dicarboxylic acid include succinic acid, adipic acid, azelaic acid, sebacic acid, terephthalic acid, and isophthalic acid.

[0035] Examples of the polyhydric alcohol include aromatic polyhydric alcohols such as those obtained by addition reaction of bisphenol with ethylene oxide, aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, glycerin, sorbitan, trimethylolpropane, and neopentyl glycol, and ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol, and polypropylene glycol.

[0036] Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutyric acid, hydroxybutylcarboxylic acid, hydroxypentanoic acid, hydroxycaproic acid, and hydroxyheptanoic acid.

[0037] Examples of the lactone acid include glycolide, ε-caprolactone glycolide, ε-caprolactone, ε-propiolactone, δ-butyrolactone, β-butyrolactone, γ-butyrolactone, pivalolactone, and δ-valerolactone.

[0038] There are no particular limitations on the method for synthesizing the polylactic acid resin used in the present invention, and it can be synthesized by a conventionally known method, for example, by direct dehydration condensation from lactic acid monomers or by ring-opening polymerization of lactic acid cyclic dimer lactide.

[0039] When direct dehydration condensation is carried out, any of L-lactic acid, D-lactic acid, DL-lactic acid, and mixtures thereof may be used. When ring-opening polymerization is carried out, any of L-lactide, D-lactide, DL-lactide, meso-lactide, and mixtures thereof may be used.

[0040] The catalyst used in the polymerization reaction to obtain the polylactic acid resin is not particularly limited, and known catalysts for lactic acid polymerization can be used. Examples include tin compounds such as tin lactate, tin tartrate, tin dicaprylate, tin dilaurate, tin dipalmitate, tin distearate, tin dioleate, tin α-naphthoate, tin β-naphthoate, and tin octoate; tin powder, tin oxide, zinc powder, zinc halide, zinc oxide, organic zinc compounds; titanium compounds such as tetrapropyl titanate; zirconium compounds such as zirconium isopropoxide; antimony compounds such as antimony trioxide; bismuth compounds such as bismuth(III) oxide; and aluminum compounds such as aluminum oxide and aluminum isopropoxide. Among these, catalysts made of tin or tin compounds are particularly preferred in terms of activity. The amount of the catalyst used is, for example, about 0.001 to 5 parts by mass per 100 parts by mass of lactide when ring-opening polymerization is carried out.

[0041] The polymerization reaction can be carried out in the presence of the above catalyst, usually at 100 to 220° C., although this temperature varies depending on the type of catalyst. It is also preferable to carry out the two-stage polymerization described in, for example, JP-A-7-247345.

[0042] Although the above description has been given of the case where polylactic acid resin is used as the biodegradable resin, the biodegradable resin used in the present invention is not limited to polylactic acid resin, and any biodegradable resin can be used.

[0043] In the composition of the present invention, the biodegradable resin may be blended with a general-purpose resin other than the biodegradable resin, if necessary, in order to improve impact strength, etc. Preferred general-purpose resins are elastic resins such as ethylene-propylene copolymer rubber and ethylene-propylene-diene copolymer.

[0044] The content of the biodegradable resin in the composition of the present invention is preferably 60 parts by mass or more, more preferably 65 parts by mass or more, even more preferably 70 parts by mass or more, and particularly preferably 75 parts by mass or more, relative to 100 parts by mass of the composition. This allows the plasticizer and the biodegradable resin to be sufficiently compatible with each other. The content of the biodegradable resin in the composition of the present invention is preferably 99 parts by mass or less, more preferably 95 parts by mass or less, even more preferably 90 parts by mass or less, and particularly preferably 85 parts by mass or less, relative to 100 parts by mass of the composition. This allows the plasticizing effect of the plasticizer to be sufficiently obtained.

[0045] The content of the plasticizer in the composition of the present invention is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more, relative to 100 parts by mass of the biodegradable resin. This allows the plasticizing effect of the plasticizer to be fully obtained. The content of the plasticizer in the composition of the present invention is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less, relative to 100 parts by mass of the biodegradable resin. This allows the plasticizer and the biodegradable resin to be fully compatible with each other.

[0046] The content of the plasticizer in the composition of the present invention is preferably 1 part by mass or more, more preferably 5 parts by mass or more, even more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more, relative to 100 parts by mass of the composition. This allows the plasticizing effect of the plasticizer to be fully obtained. The content of the plasticizer in the composition of the present invention is preferably 50 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 25 parts by mass or less, and particularly preferably 20 parts by mass or less, relative to 100 parts by mass of the composition. This allows the plasticizer and the biodegradable resin to be fully compatible with each other.

[0047] The composition of the present invention may contain optional components together with the plasticizer of the present invention. The optional components that can be contained in the composition of the present invention are described below. It is preferable to add various additives that are typically used in each resin to the composition of the present invention as needed to stabilize the composition. Examples of the additives include antioxidants such as phenolic antioxidants, sulfur-based antioxidants, and phosphorus-based antioxidants, ultraviolet absorbers, and hindered amine light stabilizers.

[0048] Examples of the phenolic antioxidants include 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, distearyl (3,5-di-tert-butyl-4-hydroxybenzyl) phosphonate, tridecyl-3,5-di-tert-butyl-4-hydroxybenzyl thioacetate, thiodiethylene bis[(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], and 4,4'-thiobis(6-tert-butyl-m-cresol). , 2-octylthio-4,6-di(3,5-di-tert-butyl-4-hydroxyphenoxy)-s-triazine, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butylic acid]glycol ester, 4,4'-butylidenebis(4,6-di-tert-butylphenol), 2,2'-ethylidenebis(4,6-di-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, bis[2-tert-butyl-4-methyl -6-(2-hydroxy-3-tert-butyl-5-methylbenzyl)phenyl] terephthalate, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl) isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene, 1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl] isocyanurate, pentaerythritol Examples of such phenols include tolfol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], 2-tert-butyl-4-methyl-6-(2-acroyloxy-3-tert-butyl-5-methylbenzyl)phenol, 3,9-bis[2-(3-tert-butyl-4-hydroxy-5-methylhydrocinnamoyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane], and triethylene glycol bis(β-(3-tert-butyl-4-hydroxy-5-methylphenyl)propionate).The amount of the phenolic antioxidant used is preferably 0.001 to 10 parts by mass, more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the biodegradable resin.

[0049] Examples of the sulfur-based antioxidant include dialkyl thiodipropionates such as dilauryl thiodipropionate, dimyristyl thiodipropionate, and distearyl thiodipropionate, and β-alkyl mercaptopropionate esters of polyols such as pentaerythritol tetra(β-dodecyl mercaptopropionate). The amount of the sulfur-based antioxidant used is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the biodegradable resin.

[0050] Examples of the phosphorus-based antioxidants include trisnonylphenyl phosphite, tris(2,4-di-tert-butylphenyl)phosphite, tris[2-tert-butyl-4-(3-tert-butyl-4-hydroxy-5-methylphenylthio)-5-methylphenyl]phosphite, tridecyl phosphite, octyldiphenyl phosphite, didecyl monophenyl phosphite, bis(tridecyl)pentaerythritol diphosphite, bis(nonylphenyl)pentaerythritol diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4,6-tri-tert-butylphenyl)pentaerythritol diphosphite, bis(2,4-dicumylphenyl)pentaerythritol diphosphite, tetrakis(tridecyl)isopropylidenediphenol diphosphite, tetrakis(tridecyl)-4 , 4'-n-butylidenebis(2-tert-butyl-5-methylphenol) diphosphite, hexakis(tridecyl)-1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane triphosphite, tetrakis(2,4-ditert-butylphenyl)biphenylene diphosphonite, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2,2'-methylenebis(4,6-tert-butylphenyl)-2-ethylhexyl Examples of suitable phosphorus-based antioxidants include octadecyl phosphite, 2,2'-methylenebis(4,6-tert-butylphenyl)-octadecyl phosphite, 2,2'-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite, tris(2-[(2,4,8,10-tetra-tert-butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]ethyl)amine, and phosphite of 2-ethyl-2-butylpropylene glycol and 2,4,6-tri-tert-butylphenol. The amount of the phosphorus-based antioxidant used is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the biodegradable resin.

[0051] Among these antioxidants, phenol-based antioxidants and phosphorus-based antioxidants are particularly preferred because they prevent the biodegradable resin from becoming discolored.

[0052] Examples of the ultraviolet absorber include 2-hydroxybenzophenones such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-tert-butyl-4'-(2-methacryloyloxyethoxyethoxy)benzophenone, and 5,5'-methylenebis(2-hydroxy-4-methoxybenzophenone); 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-tert-octylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di-tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'-dodecyl-5'-methylphenyl)benzotriazole, and 2-(2'-hydroxy-3'-tert-butyl-5'-C ７～９2-(2'-hydroxyphenyl)benzotriazoles such as mixed alkoxycarbonylethylphenyl)triazole, 2-(2'-hydroxy-3',5'-dicumylphenyl)benzotriazole, and polyethylene glycol esters of 2-(2'-hydroxy-3'-tert-butyl-5'-carboxyphenyl)benzotriazole; 2-(2-hydroxy-4-hexyloxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-1,3,5-triazine, 2-(2-hydroxy-4-octoxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-acryloyloxyethoxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, 2-(2-hydroxy-4-(2-ethylhexyloxyloyloxyethoxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine, triaryltriazines such as 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-di-tert-butylphenyl)-1,3,5-triazine, and 2-(2-hydroxy-4-propoxy-5-methylphenyl)-4,6-bis(2,4-di-tert-butylphenyl)-1,3,5-triazine; phenyl salicylate, resorcinol monobenzoate, 2,4-di-tert-butylphenyl-3,5-di-tert-butyl-4-hydroxybenzoate, 2,4-di-tert-amylphenyl Examples of the ultraviolet absorber include benzoates such as hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate and hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate; substituted oxanilides such as 2-ethyl-2'-ethoxyoxanilide and 2-ethoxy-4'-dodecyloxanilide; and cyanoacrylates such as ethyl-α-cyano-β,β-diphenylacrylate and methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate. The amount of the ultraviolet absorber used is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the biodegradable resin.

[0053] Examples of the hindered amine light stabilizer include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)sebacate, bis(1-octoxy-2,2,6,6-tetramethyl-4-piperidyl)sebacate, and 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate. tetrakis(2,2,6,6-tetramethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidyl)-1,2,3,4-butanetetracarboxylate, bis(2,2,6,6-tetramethyl-4-piperidyl)bis(tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)bis(tridecyl)-1,2,3,4-butanetetracarboxylate carboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, 3,9-bis(1,1-dimethyl-2-[tris(2,2,6,6-tetramethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy]ethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 3,9-bis(1,1-dimethyl-2-[tris(1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyloxy)butylcarbonyloxy]ethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, ]ethyl)-2,4,8,10-tetraoxaspiro[5.5]undecane, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / 2,4-dichloro-6-tert-octylamino-s-triazine polycondensate, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazin-6-yl]-1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazin-6-yl]-1,5,8,12-tetraazadodecane, 1,6,11-tris[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazin-6-ylamino]undecane, 1 , 6,11-tris[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino)-s-triazin-6-ylamino]undecane, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane / dibromoethane polycondensate, etc. The amount of the hindered amine light stabilizer used is preferably 0.001 to 10 parts by mass, and more preferably 0.01 to 5 parts by mass, per 100 parts by mass of the biodegradable resin.

[0054] The composition of the present invention may further contain, as necessary, additives that are commonly used in synthetic resins, such as processing aids, crosslinking agents, antistatic agents, antifogging agents, anti-plate-out agents, surface treatment agents, plasticizers other than those of the present invention, fillers, lubricants, nucleating agents, clarifying agents, reinforcing materials, flame retardants, fluorescent agents, antifungal agents, bactericides, foaming agents, metal deactivators, release agents, pigments, silicone oils, and silane coupling agents, within limits that do not impair the effects of the present invention.

[0055] Methods for adding the above-mentioned optional components include adding them to the biodegradable resin separately from the plasticizer of the present invention, mixing the above-mentioned plasticizer in advance in the desired ratio with a binder, wax, solvent, granulation aid such as silica, etc., which are used as needed, and then granulating the mixture to form a one-pack composite additive, which is then added to the biodegradable resin, and preparing a masterbatch containing the plasticizer of the present invention and the above-mentioned optional components, which is then added to the biodegradable resin.

[0056] The timing of blending the plasticizer of the present invention and optional components into the composition of the present invention is not particularly limited. For example, two or more selected from the blending components other than the biodegradable resin may be packed together and then blended with the biodegradable resin, or each component other than the biodegradable resin may be blended sequentially with the biodegradable resin. When multiple components are packed together, each component may be crushed and then mixed, or mixed and then crushed. When the biodegradable resin is a polymer blend, each component other than the biodegradable resin may be added to a pre-blended compound, or may be added during the blending process.

[0057] The method for producing the composition of the present invention is not particularly limited, and known methods can be applied. Specific production methods include a method of mixing using a conventional blender, mixer, etc., a method of melt-kneading using an extruder, etc., a method of mixing together with a solvent and then solution-casting, etc.

[0058] The shape of the composition of the present invention is not particularly limited, and various shapes can be used, such as pellets, granules, powder, lumps, flakes, and strands, and from the viewpoint of handleability, pellets or granules are preferred.

[0059] <Molded Article> The molded article of the present invention is obtained by molding the above-mentioned composition. The molding method of the above-mentioned composition is not particularly limited and can be appropriately selected depending on the application, and examples thereof include injection molding, extrusion molding, co-extrusion molding, blow molding, press molding, cast molding, roll molding, vacuum molding, rotational molding, calendar molding, slush molding, dip molding, foam molding, additive manufacturing, T-die casting molding, inflation molding, thermoforming molding, etc.

[0060] The use of the molded article of the present invention is not particularly limited, and it can be used for various purposes, such as daily necessities, packaging materials, agricultural materials, electric and electronic parts, machine parts, optical instruments, building materials, and automobile parts.

[0061] The molded article of the present invention can be used in a wide range of industrial fields, such as electricity, electronics, and communications, agriculture, forestry, and fisheries, mining, construction, food, textiles, clothing, medicine, coal, petroleum, rubber, leather, automobiles, precision instruments, wood, building materials, civil engineering, furniture, printing, and musical instruments. Specifically, the composition of the present invention and molded articles thereof can be used for window envelopes, plastic envelopes, twist packaging, printed laminated paper, laminated bags, labels, garbage bags, shopping bags, heavy-duty bags, sanitary materials, general packaging and the like, overwrapping, tableware containers, blister packs, clear cases, trays, boards, cushioning materials, slit yarns, sandbags, flexible container bags, ropes, strings, packing bands, fishing line, woven and knitted fabrics, nets, filters, clothing, industrial materials, braided cords, spun yarns, multi-layered yarns, interior decoration, wadding, staple fiber nonwoven fabrics, agricultural materials, gardening materials, civil engineering materials, bags, carpet backings, bag-making materials, packaging materials, household materials, household goods, electronic and office automation equipment housings, automotive interior materials, bottles, and the like.

[0062] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various other configurations may be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of achieving the object of the present invention are included in the present invention.

[0063] The present invention will be specifically illustrated below with examples and comparative examples. The materials, substances, blending amounts and ratios, operations, etc. shown in the following examples can be appropriately changed without departing from the spirit of the present invention. Therefore, the present invention is not limited in any way by the following examples. In the following examples, unless otherwise specified, the blending amounts of components are based on mass.

[0064] Details of each component used in the examples and comparative examples are shown below. Biodegradable resin: polylactic acid resin (trade name: Ingeo 2003D, manufactured by Nature Works, weight average molecular weight: 180,000, melt mass flow rate [210°C, load 2.16 kg]: 6 g / 10 min) Plasticizer 1: main component: dipropylene glycol dibenzoate (content 99.2%, hydroxyl value: 2 mg KOH / g) Plasticizer 2: main component: dipropylene glycol dibenzoate (content 93.6%, hydroxyl value: 15 mg KOH / g) Plasticizer 3: main component: diethylene glycol dibenzoate (content 99.0%, hydroxyl value: 2 mg KOH / g) Plasticizer 4: main component: diethylene glycol dibenzoate (content 92.9%, hydroxyl value: 15 mg KOH / g) Comparative plasticizer C1: Main component: dipropylene glycol dibenzoate (content 86.4%, hydroxyl value: 32 mg KOH / g) Comparative plasticizer C2: Main component: diethylene glycol dibenzoate (content 85.7%, hydroxyl value: 30 mg KOH / g) Comparative plasticizer C3: Main component: bis[2-(2-butoxyethoxy)ethyl] adipate (content 99.0%, hydroxyl value: 2 mg KOH / g) Comparative plasticizer C4: Main component: bis[2-(2-butoxyethoxy)ethyl] adipate (content 84.5%, hydroxyl value: 30 mg KOH / g)

[0065] <Heat Resistance Evaluation> The heat resistance of the above-mentioned plasticizers 1 to 4 and comparative plasticizers C1 and C2 was evaluated using a thermogravimetric / differential thermal analyzer (device name: Thermo plus EVO, manufactured by Rigaku). Approximately 10 mg of plasticizer was precisely weighed and heated from 30°C to 400°C at a heating rate of 10°C / min in a nitrogen atmosphere, and the weight loss rate (wt%) was measured. The temperature (°C) at which the weight had decreased by 5 wt% from the weight at the start of the measurement was determined. This temperature is referred to as the 5% weight loss temperature. The results are shown in Table 1.

[0066]

[0067] From the results shown in Table 1, the plasticizers of the present invention had a higher 5% weight loss temperature than the comparative plasticizers, confirming that the plasticizers of the present invention have excellent heat resistance.

[0068] Examples 1 to 13, Comparative Examples 1 to 11 Production of Compositions Resin strands were obtained by melt-kneading the components in the proportions shown in Tables 2 and 3. Melt-kneading was carried out using a Laboplastomill (manufactured by Toyo Seiki Seisakusho) connected to a twin-screw segment extruder (device name: 2D30W2) at a melt temperature of 220°C and a screw speed of 40 rpm. The obtained resin strands were cut with a pelletizer to obtain pelletized compositions.

[0069] <Film Production> A cast film having a thickness of 200 μm was produced using the pellet-like composition obtained above. The film was produced using a Laboplastomill μ (manufactured by Toyo Seiki Seisakusho) connected to a single-screw extruder (device name: D1220B) and a T-die (device name: MT60B) under the following conditions: melt temperature 210°C, screw speed 20 rpm, T-die extrusion temperature 210°C, chill roll temperature 30°C, and roll rotation speed 0.30 to 0.35 m / min. The obtained film was allowed to stand for 48 hours under conditions of 23°C and 50% RH, and then subjected to the evaluation described below.

[0070] <Plasticity Evaluation 1: Tensile Elongation> JIS No. 5 dumbbell-shaped test pieces were punched out from the film obtained above, with the film take-up direction (MD) aligned vertically. The tensile elongation (%) was measured in accordance with JIS K7127 at a test speed of 100 mm / min, a chuck distance of 80 mm, and a gauge length of 25 mm. The results are shown in Tables 2 and 3.

[0071] <Plasticity Evaluation 2: Glass Transition Temperature> The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC-EVO, manufactured by Rigaku). A 4 mg sample was cut out from the film obtained above, and the Tg was determined by the midpoint method from the DSC curve obtained when the temperature was increased from -20°C to 190°C at a heating rate of 10°C / min under a nitrogen atmosphere. The results are shown in Tables 2 and 3.

[0072]

[0073]

[0074] As shown in the plasticity evaluation results of biodegradable resins shown in Tables 2 and 3, the compositions containing the plasticizer of the present invention (Examples 1 to 13) had higher tensile elongation and lower glass transition temperatures than the composition not containing the plasticizer of the present invention (Comparative Example 1) and the compositions containing dibenzoate compounds with high hydroxyl values ​​(Comparative Examples 2 to 7). This confirmed that the compositions of the present invention have excellent plasticity.

[0075] Furthermore, in the compositions (Comparative Examples 8 to 11) containing plasticizers that did not contain the dibenzoate compound represented by general formula (1), the difference in hydroxyl value did not affect plasticity, indicating that the effect of the present invention is specific to plasticizers that contain the dibenzoate compound represented by general formula (1).

Claims

1. A plasticizer for biodegradable resins, comprising a dibenzoate compound represented by the following general formula (1), having a hydroxyl value of 0.1 to 20 mgKOH / g: In the formula, R １ represents an alkanediyl group having 1 to 8 carbon atoms, and n represents an integer of 1 to 8.

2. The plasticizer according to claim 1, wherein R in general formula (1) １ represents an alkylene group having 2 to 3 carbon atoms.

3. The plasticizer according to claim 1, wherein n in the general formula (1) represents an integer of 1 to 3.

4. A composition comprising a biodegradable resin and the plasticizer according to any one of claims 1 to 3.

5. The composition according to claim 4, wherein the content of the plasticizer is 0.1 to 50 parts by mass per 100 parts by mass of the biodegradable resin.

6. A molded article obtained from the composition according to claim 4.