Plasticizers for biodegradable resins, biodegradable resin compositions and their molded articles

Abstract

To provide a plasticizer for biodegradable resin that has excellent compatibility with biodegradable resin, and can sufficiently plasticize the biodegradable resin.SOLUTION: The present invention provides a plasticizer for biodegradable resin that is polyester represented by the general formula (1) (where B11 and B12 independently represent an alcohol residue of a monoalcohol having an oxygen-containing heterocycle).SELECTED DRAWING: None

Description

[Technical Field]

[0001] This invention relates to a plasticizer for biodegradable resins, a biodegradable resin composition, and molded articles thereof. [Background technology]

[0002] General-purpose plastics such as polyvinyl chloride (PVC) are used in a wide range of applications, and these general-purpose plastics are typically made flexible by adding plasticizers before use. However, because general-purpose plastics are not easily biodegraded, there is a growing movement to switch from general-purpose plastics to biodegradable resins in recent years, driven by an emphasis on sustainability.

[0003] Because biodegradable resins are generally more polar than general-purpose plastics, there is a need for plasticizers suitable for biodegradable resins that differ from conventional plasticizers for general-purpose plastics. To meet this need, various plasticizers for biodegradable resins have been proposed (for example, Patent Documents 1-2). [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2017-218529 [Patent Document 2] International Publication No. 2014 / 061644 [Overview of the project] [Problems that the invention aims to solve]

[0005] When the plasticizers disclosed in Patent Documents 1-2 were added in large quantities to biodegradable resins, there was a problem of bleed-out due to insufficient compatibility. Thus, because the plasticizers in Patent Documents 1-2 had insufficient compatibility with biodegradable resins, there were limitations to the plasticizing effect that could be obtained.

[0006] The problem that this invention aims to solve is to provide a plasticizer for biodegradable resins that has excellent compatibility with biodegradable resins and can sufficiently plasticize biodegradable resins. [Means for solving the problem]

[0007] The present invention relates to a plasticizer for biodegradable resins, which is a polyester represented by the following general formula (1).

[0008] [ka] (In the above general formula (1), B 11 and B 12 These are, independently, alcohol residues of a monoalcohol having an oxygen-containing heterocycle. A is independently an alkylenedicarboxylic acid residue having 2 to 12 carbon atoms or an aryldicarboxylic acid residue having 6 to 18 carbon atoms. G is an alkylene glycol residue having 2 to 12 carbon atoms or an oxyalkylene glycol residue having 4 to 12 carbon atoms. n represents the number of repetitions. [Effects of the Invention]

[0009] The present invention provides a plasticizer for biodegradable resins that has excellent compatibility with biodegradable resins and can sufficiently plasticize biodegradable resins. [Modes for carrying out the invention]

[0010] The following describes one embodiment of the present invention. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications without impairing the effects of the present invention. Furthermore, the alcohols and carboxylic acids described below may be derived from petroleum or biomass.

[0011] [Plasticizer for biodegradable resins] The plasticizer for biodegradable resins of the present invention is a polyester represented by the following general formula (1) (hereinafter sometimes referred to as "the polyester of the present invention").

[0012] [Chemical formula] (In the general formula (1), B 11 and B 12 are each independently an alcohol residue of a monoalcohol having an oxygen-containing heterocyclic ring, A is each independently an alkylene dicarboxylic acid residue having 2 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 18 carbon atoms, G is an alkylene glycol residue having 2 to 12 carbon atoms or an oxyalkylene glycol residue having 4 to 12 carbon atoms, n represents the number of repetitions. The plurality of As within the parentheses may be the same as or different from each other. (The plurality of Gs within the parentheses may be the same as or different from each other.)

[0013] In the present invention, the "alcohol residue" refers to the remaining organic group obtained by removing the hydroxyl group from an alcohol. In the present invention, the "glycol residue" refers to the remaining organic group obtained by removing the hydroxyl group from a glycol. In the present invention, the "carboxylic acid residue" refers to the remaining organic group obtained by removing the carboxyl group from a carboxylic acid. Note that for the number of carbon atoms of the carboxylic acid residue, the carbon atom in the carboxyl group is not included.

[0014] In the plasticizer for biodegradable resins of the present invention, since the terminals are sealed with a compound having an oxygen-containing heterocyclic ring, it generally shows excellent compatibility with highly polar biodegradable resins.

[0015] B 11 and B 12A monoalcohol having an oxygen-containing heterocycle is a compound having an oxygen-containing heterocycle and one hydroxyl group, for example, a compound represented by the following general formula (2).

[0016] [ka] (In the above general formula (2), X is an oxygen-containing heterocycle that is an epoxy ring, oxetane ring, tetrahydrofuran ring, oxabicyclo ring, furan ring, or pyran ring. Y is a single bond or a divalent organic group. Z is a substituent other than a hydroxyl group, m is a non-negative integer.

[0017] The divalent organic group of Y is preferably an alkylene group having 1 to 10 carbon atoms or an alkylene oxy group having 1 to 10 carbon atoms.

[0018] Examples of alkylene groups of Y having 1 to 10 carbon atoms include methylene group, ethylene group, n-propylene group, n-butylene group, n-pentylene group, n-hexylene group, n-heptylene group, n-octylene group, n-nonylene group, n-decylene group, n-dodecylene group, isopropylene group, 2-methylpropylene group, 2-methylhexylene group, and tetramethylethylene group.

[0019] The alkylene group of Y having 1 to 10 carbon atoms is preferably an alkylene group having 1 to 6 carbon atoms, more preferably an alkylene group having 1 to 3 carbon atoms, and even more preferably a methylene group.

[0020] The alkylene oxy group of Y having 1 to 10 carbon atoms is, for example, a group in which one or more of the -CH2- in the alkylene group are replaced with -O-. The alkylene oxy group of Y having 1 to 10 carbon atoms is preferably an alkylene oxy group having 1 to 8 carbon atoms, and more preferably a methylene oxy group, ethylene oxy group, propylene oxy group, oxytrimethylene group, butylene oxy group, oxytetramethylene group, pentylene oxy group, heptylene oxy group, or octylene oxy group.

[0021] If the divalent organic group of Y is an alkylene group having 1 to 10 carbon atoms or an alkylene oxy group having 1 to 10 carbon atoms, then some of the -CH2- in these divalent organic groups may be replaced by carbonyl groups (-C(=O)-) or phenylene groups.

[0022] The substituent of Z is not particularly limited as long as it is not a hydroxyl group, and examples include alkyl groups with 1 to 6 carbon atoms and aryl groups with 6 to 12 carbon atoms.

[0023] The upper limit of m is a number corresponding to the number of substitutions possible in the oxygen-containing heterocycle of X. For example, if X is a tetrahydrofuran ring, the upper limit of m is 7, and if X is a furan ring, the upper limit of m is 3.

[0024] B 11 and B 12 Examples of alcohol residues in monoalcohols having an oxygen-containing heterocycle include tetrahydrofurfuryl alcohol residues (tetrahydrofuran-2-methanol residues), furfuryl alcohol residues, tetrahydropyran-2-methanol residues, and tetrahydro-4-pyranol residues. Among these, from a sustainability perspective, tetrahydrofurfuryl alcohol residue, which is a plant-derived component, is preferred.

[0025] The fatty chain of aliphatic dicarboxylic acid residues of A having 2 to 12 carbon atoms may be linear or branched, and may contain an alicyclic structure and / or an ether bond (-O-).

[0026] Examples of aliphatic dicarboxylic acid residues of A with 2 to 12 carbon atoms include succinic acid residues, glutaric acid residues, adipic acid residues, maleic acid residues, pimelic acid residues, suberic acid residues, sebaciate residues, azelaic acid residues, and cyclohexanedicarboxylic acid residues.

[0027] Examples of aryldicarboxylic acid residues of A with 6 to 18 carbon atoms include phthalic acid residues, terephthalic acid residues, isophthalic acid residues, 1,4-naphthalenedicarboxylic acid residues, 2,3-naphthalenedicarboxylic acid residues, 2,6-naphthalenedicarboxylic acid residues, 2,7-naphthalenedicarboxylic acid residues, and 1,8-naphthalenedicarboxylic acid residues.

[0028] A is preferably an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms, more preferably an aliphatic dicarboxylic acid residue having 2 to 8 carbon atoms, even more preferably a succinic acid residue, a glutaric acid residue, an adipic acid residue, a sebacic acid residue, or an azelaic acid residue, and most preferably a succinic acid residue, a glutaric acid residue, or an adipic acid residue.

[0029] Examples of alkylene glycol residues of G with 2 to 12 carbon atoms include ethylene glycol residues, 1,2-propylene glycol residues, 1,3-propanediol residues, 1,2-butanediol residues, 1,3-butanediol residues, 2-methyl-1,3-propanediol residues, 1,4-butanediol residues, 1,5-pentanediol residues, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residues, and 2,2-diethyl-1,3-propanediol (3,3 Examples include residues such as dimethylolpentane, 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol.

[0030] The fatty chain of the alkylene glycol residue of G having 2 to 12 carbon atoms may include an alicyclic structure. Examples of aliphatic diol residues having 2 to 12 carbon atoms that include such an alicyclic structure include 1,3-cyclopentanediol residues, 1,2-cyclohexanediol residues, 1,3-cyclohexanediol residues, 1,4-cyclohexanediol residues, 1,2-cyclohexanedimethanol residues, and 1,4-cyclohexanedimethanol residues.

[0031] The alkylene glycol residue of G having 2 to 12 carbon atoms is preferably an alkylene glycol residue having 2 to 6 carbon atoms, and more preferably an ethylene glycol residue, a 1,2-propylene glycol residue, a 1,3-propanediol residue, a 1,2-butanediol residue, a 1,3-butanediol residue, a 2-methyl-1,3-propanediol residue, a neopentyl glycol residue, a diethylene glycol residue, or a dipropylene glycol residue.

[0032] The oxyalkylene glycol residues of G, which have 4 to 12 carbon atoms, are groups in which an ether bond (-O-) is inserted between any one carbon-carbon bond of an alkylene glycol residue. Examples include diethylene glycol residues, triethylene glycol residues, tetraethylene glycol residues, dipropylene glycol residues, and tripropylene glycol residues.

[0033] G is preferably an ethylene glycol residue, a 1,2-propylene glycol residue, a 1,3-propanediol residue, a 1,2-butanediol residue, a 1,3-butanediol residue, a 2-methyl-1,3-propanediol residue, a neopentyl glycol residue, a diethylene glycol residue, or a dipropylene glycol residue, and more preferably an ethylene glycol residue, a diethylene glycol residue, or a 1,2-propylene glycol residue.

[0034] The number of repetitions of n is, for example, an integer in the range of 0 to 20. The average value of the number of repetitions of n is preferably in the range of 0.2 to 10.0, more preferably in the range of 0.3 to 5.0, and more preferably in the range of 0.5 to 3.0. The average number of repeats of n can be calculated from the number-average molecular weight of the polyester of the present invention.

[0035] The number-average molecular weight (Mn) of the polyester of the present invention is, for example, in the range of 100 to 5,000, preferably in the range of 300 to 3,000, more preferably in the range of 350 to 2,000, and even more preferably in the range of 400 to 980. The above number-average molecular weight (Mn) is a value converted to polystyrene based on gel permeation chromatography (GPC) measurement, and is measured by the method described in the examples.

[0036] The acid value of the polyester of the present invention is, for example, 10 mg KOH / g or less, preferably 5 mg KOH / g or less, more preferably 3 mg KOH / g or less, and even more preferably 1 mg KOH / g or less. The lower limit of the acid value of the polyester of the present invention is not particularly limited, but for example, it is 0 mgKOH / g. The acid value of the above polyester is confirmed by the method described in the examples.

[0037] The properties of the polyester of the present invention vary depending on the number-average molecular weight and composition, but are typically liquid, solid, or paste-like at room temperature.

[0038] The polyester of the present invention may be any polyester that satisfies the above general formula (1), and for example, two or more polyesters with different structures may be used.

[0039] The polyester of the present invention is obtained by using reaction raw materials including a monoalcohol having an oxygen-containing heterocyclic ring, an alkylene dicarboxylic acid and / or an aryl dicarboxylic acid, and an alkylene glycol and / or an oxyalkylene glycol. Here, the reaction raw materials mean the raw materials constituting the polyester of the present invention, and do not include solvents and catalysts that do not constitute the polyester. The method for producing the polyester of the present invention is not particularly limited and can be produced by a known method, and can be produced by the production method described later.

[0040] The monoalcohol having an oxygen-containing heterocyclic ring used in the production of the polyester of the present invention is a monoalcohol corresponding to the alcohol residue of the monoalcohol having an oxygen-containing heterocyclic ring of B 11 and B 12 and the monoalcohol having an oxygen-containing heterocyclic ring to be used may be used alone or in combination of two or more. The alkylene dicarboxylic acid used in the production of the polyester of the present invention is an alkylene dicarboxylic acid corresponding to the alkylene dicarboxylic acid residue having 2 to 12 carbon atoms of A, and the alkylene dicarboxylic acid to be used may be used alone or in combination of two or more. The aryl dicarboxylic acid used in the production of the polyester of the present invention is an aryl dicarboxylic acid corresponding to the aryl dicarboxylic acid residue having 6 to 18 carbon atoms of A, and the aryl dicarboxylic acid to be used may be used alone or in combination of two or more. The alkylene glycol used in the production of the polyester of the present invention is an alkylene glycol corresponding to the alkylene glycol residue having 2 to 12 carbon atoms of G, and the alkylene glycol to be used may be used alone or in combination of two or more. The oxyalkylene glycol used in the production of the polyester of the present invention is an oxyalkylene glycol corresponding to the oxyalkylene glycol residue having 4 to 12 carbon atoms of G, and the oxyalkylene glycol to be used may be used alone or in combination of two or more.

[0041] The oxygen-containing heterocyclic monoalcohols, alkylenedicarboxylic acids, alkylene glycols, and oxyalkylene glycols used in the production of the polyester of the present invention can all be derivatives thereof. Examples of such derivatives include esterified compounds, acid chlorides, anhydrides, and cyclic esters.

[0042] The polyester of the present invention can be produced, for example, by reacting a monoalcohol having an oxygen-containing heterocycle, alkylenedicarboxylic acid and / or aryldicarboxylic acid, and alkylene glycol and / or oxyalkylene glycol, which constitute each residue of the polyester of the present invention, all at once under conditions in which the equivalent amount of hydroxyl groups contained in the reaction raw materials is greater than the equivalent amount of carboxyl groups. The polyester of the present invention can also be produced, for example, by reacting alkylenedicarboxylic acid and / or aryldicarboxylic acid, and alkylene glycol and / or oxyalkylene glycol, which constitute each residue of the polyester of the present invention, under conditions in which the equivalent amount of carboxyl groups contained in the reaction raw materials is greater than the equivalent amount of hydroxyl groups, thereby obtaining a polyester having carboxyl groups at the ends of the main chain, and then further reacting the obtained polyester with a monoalcohol having an oxygen-containing heterocycle.

[0043] In the production of polyester according to the present invention, the reaction of the reaction raw materials may be carried out in the presence of an esterification catalyst as needed, for example, in a temperature range of 170 to 250°C for 10 to 25 hours. Furthermore, the temperature, time, and other conditions for the esterification reaction are not particularly limited and may be set as appropriate.

[0044] Examples of the esterification catalysts include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate; zinc-based catalysts such as zinc acetate; tin-based catalysts such as tin octoate and dibutyltin oxide; and organic sulfonic acid-based catalysts such as p-toluenesulfonic acid.

[0045] The amount of esterification catalyst used can be set as appropriate, but it is usually used in the range of 0.0001 to 0.1 parts by mass per 100 parts by mass of the total amount of reaction raw materials.

[0046] [Biodegradable resin composition] The biodegradable resin composition of the present invention contains a plasticizer for biodegradable resins and a biodegradable resin. The biodegradable resin plasticizer of the present invention exhibits excellent compatibility with generally highly polar biodegradable resins because the polyester ends are sealed with a compound having an oxygen-containing heterocycle. Furthermore, the biodegradable resin plasticizer of the present invention has a longer chain than monoester and diester compounds commonly used as plasticizers, and therefore also exhibits excellent non-volatility (ability to remain in biodegradable resins).

[0047] The biodegradable resins contained in the biodegradable resin composition of the present invention include cellulose ester resin, polylactic acid (PLA), polyethylene succinate (PES), polyethylene terephthalate succinate (PETS), polybutylene succinate (PBS), polybutylene adipate terephthalate (PBAT), polyethylene adipate terephthalate (PEAT), polybutylene succinate terephthalate (PBST), polyethylene succinate terephthalate (PEST), and polybutylene succinate adipate (PBSA). Examples include polybutylene succinate carbonate (PEC), polybutylene succinate adipate terephthalate (PBSAT), polyethylene succinate adipate terephthalate (PESAT), polytetramethylene adipate terephthalate (PTMAT), polyhydroxybutyrate (PHB), polyhydroxybutyrate-hydroxyhexanoic acid (PHBH), polyhydroxybutyrate-hydroxyvalate (PHBV), polycaprolactone (PCL), and polycaprolactone-butylene succinate (PCLBS). The biodegradable resin to be used can be determined according to the intended application, and one type of biodegradable resin may be used alone, or two or more types may be used in combination.

[0048] The biodegradable resin is preferably one or more selected from the group consisting of cellulose ester resin, polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polyhydroxybutyrate-hydroxyhexanoic acid, polybutylene succinate adipate, and polyethylene terephthalate succinate, and more preferably cellulose ester resin.

[0049] Examples of cellulose ester resins include cellulose acetate (CA), cellulose diacetate (DAC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), cellulose acetate phthalate, and polycaprolactone-grafted cellulose acetate. Among these, acetylated celluloses such as cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose acetate propionate, and cellulose acetate butyrate are preferred due to their good transparency, processability, and mechanical properties (tensile strength, flexural strength, flexural elasticity, etc.), with cellulose diacetate being the most preferred. Cellulose ester resins can be used individually or in combination of two or more types.

[0050] When the cellulose ester resin is acetylated cellulose, its degree of polymerization is preferably in the range of 100 to 400, and more preferably in the range of 100 to 200. Furthermore, when the cellulose ester resin is acetylated cellulose, the upper limit of the degree of substitution of acetyl groups is preferably 3.0 or less, more preferably 2.7 or less, and even more preferably in the range of 2.6 or less. The lower limit of the degree of substitution is preferably 1.0 or more, preferably 1.5 or more, and even more preferably 2.0 or more. If the degree of polymerization and substitution of the cellulose acetate are within the above range, a film with excellent mechanical properties can be obtained. In the present invention, it is more preferable to use so-called cellulose diacetate.

[0051] Furthermore, the "average degree of polymerization" can be measured in accordance with the intrinsic viscosity method by Uda et al. (Kazuo Uda, Hideo Saito, "Journal of the Textile Institute," Vol. 18, No. 1, pp. 105-120, 1962). Specifically, 0.2 g of oven-dried cellulose ester is accurately weighed and dissolved in 100 ml of a mixed solvent of methylene chloride:ethanol = 9:1 (mass ratio). The time it takes for this solution to fall is measured using an Ostwald viscometer in a constant temperature water bath at 25°C, and the average degree of polymerization is calculated using the following [Equation 1]. Average degree of polymerization=[η] / K m ... [Formula 1] [η]=(lnη rel ) / C η rel =T / T0 K m = 6 × 10 -4 T: Drop time of the measurement sample (seconds) T0: Solvent settling time (seconds) C: Sample concentration (g / l)

[0052] The cellulose ester resin may be a commercially available product, such as cellulose diacetates like "L-20" (average acetyl substitution degree 2.41, average degree of polymerization 145), "L-30" (average acetyl substitution degree 2.41, average degree of polymerization 160), "L-50" (average acetyl substitution degree 2.41, average degree of polymerization 180), and "L-70" (average acetyl substitution degree 2.41, average degree of polymerization 190) manufactured by Daicel Corporation, and "LT-35" manufactured by Daicel Corporation. Examples include cellulose triacetates such as "LT-105" (average acetyl substitution degree 2.87, average degree of polymerization 270), "CAP482-20" and "CAP141-20" from Eastman Chemical, cellulose acetate propionates such as "CAB381-20" and "CAB171-15", and cellulose acetates such as "CA398-30".

[0053] The content of the biodegradable resin plasticizer of the present invention in the biodegradable resin composition of the present invention is preferably in the range of 1 to 100 parts by mass, more preferably in the range of 5 to 60 parts by mass, more preferably in the range of 10 to 50 parts by mass, and even more preferably in the range of 20 to 45 parts by mass, per 100 parts by mass of biodegradable resin, from the viewpoint of compatibility with the biodegradable resin.

[0054] The total content of the biodegradable resin and the biodegradable resin plasticizer of the present invention in the biodegradable resin composition of the present invention is, for example, 80% by mass or more, 90% by mass or more, or 95% by mass or more of the solid content in the composition. The upper limit of the total content of the biodegradable resin and the biodegradable resin plasticizer of the present invention is not particularly limited, and is, for example, 100% by mass or less, 95% by mass or less, or 90% by mass or less.

[0055] The biodegradable resin composition of the present invention may contain a biodegradable resin and the biodegradable resin plasticizer of the present invention, and may also contain a non-biodegradable resin, a plasticizer other than the biodegradable resin plasticizer of the present invention (other plasticizers), other additives, etc.

[0056] The non-biodegradable resin is not particularly limited and includes polyolefins, polyesters, polysulfides, polyvinyl chlorides, modified polysulfides, silicone resins, modified silicone resins, acrylic urethane resins, epoxy resins, polyurethanes, acrylic resins, polyesters, unsaturated polyesters, and the like.

[0057] Other plasticizers include, for example, benzoic acid esters such as diethylene glycol dibenzoate; phthalate esters such as dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DOP), diisononyl phthalate (DINP), diisodecyl phthalate (DIDP), diundecyl phthalate (DUP), and ditridecyl phthalate (DTDP); terephthalate esters such as bis(2-ethylhexyl) terephthalate (DOTP); isof Isophthalate esters such as bis(2-ethylhexyl) talate (DOIP); pyromellitic acid esters such as tetra-2-ethylhexyl pyromellitic acid (TOPM); aliphatic dibasic acid esters such as di-2-ethylhexyl adipate (DOA), diisononyl adipate (DINA), diisodecyl adipate (DIDA), di-2-ethylhexyl sebacate (DOS), and diisononyl sebacate (DINS); tri-2-ethylhexyl phosphate Examples include phosphate esters such as syl (TOP) and tricresyl phosphate (TCP); alkyl esters of polyhydric alcohols such as pentaerythritol; polyesters with molecular weights of 800 to 4,000 synthesized by polyesterization of dibasic acids such as adipic acid with glycols; epoxidized esters such as epoxidized soybean oil and epoxidized linseed oil; alicyclic dibasic acids such as diisononyl hexahydrophthalate; fatty acid glycol esters such as 1,4-butanediol dicaprate; citrate esters such as triethyl acetyl citrate (ATEC), triethyl citrate (TEC), tributyl acetyl citrate (ATBC), and tributyl citrate (TBC); glycerin esters such as triacetin and diacetin; chlorinated paraffins obtained by chlorinating paraffin wax and n-paraffin; chlorinated fatty acid esters such as chlorinated stearate; and higher fatty acid esters such as butyl oleate.

[0058] When the biodegradable resin composition of the present invention uses the above-mentioned other plasticizers, the content of the other plasticizers is, for example, in the range of 10 to 300 parts by mass, preferably in the range of 20 to 200 parts by mass, per 100 parts by mass of the biodegradable resin plasticizer of the present invention.

[0059] Examples of the aforementioned other additives include flame retardants, stabilizers, stabilizing aids, colorants, processing aids, fillers, antioxidants (anti-aging agents), UV absorbers, light stabilizers, lubricants, antistatic agents, crosslinking aids, and the like.

[0060] [Method for producing biodegradable resin compositions] The method for producing the biodegradable resin composition of the present invention is not particularly limited. For example, a biodegradable resin, the biodegradable resin plasticizer of the present invention, and the above-mentioned other additives can be obtained by melt-kneading using a melt-kneading machine such as a single-screw extruder, twin-screw extruder, Banbury mixer, Brabender, or various kneaders.

[0061] [Molded articles made from biodegradable resin compositions] The biodegradable resin composition of the present invention can be molded by various molding methods applicable to general-purpose plastics. Examples of the above molding methods include compression molding (compression molding, lamination molding, stampable molding), injection molding, extrusion molding and co-extrusion molding (film molding, lamination molding, pipe molding, wire / cable molding, and shaped material molding using inflation or T-die methods), hot press molding, hollow molding (various blow molding methods), calendering, solid molding (uniaxial stretching, biaxial stretching, roll rolling, stretch-oriented nonwoven fabric molding, thermoforming (vacuum forming, pressure forming), plastic processing, powder molding (rotational molding), and various nonwoven fabric molding methods (dry method, adhesive method, entanglement method, spunbond method, etc.). Injection molding, extrusion molding, compression molding, or hot press molding are suitably applied. Specifically, sheets, films, and containers are preferred forms.

[0062] The molded product obtained above may be subjected to secondary processing. Examples of such secondary processing include embossing, painting, bonding, printing, metallizing (plating, etc.), machining, and surface treatment (antistatic treatment, corona discharge treatment, plasma treatment, photochromism treatment, physical vapor deposition, chemical vapor deposition, coating, etc.).

[0063] The molded articles obtained from the biodegradable resin composition of the present invention are composed of biodegradable resin and are therefore biodegradable, resulting in molded articles with a low environmental impact.

[0064] Molded articles obtained from the biodegradable resin composition of the present invention are suitable for a wide range of applications, such as packaging materials for liquids, powders, and solids, agricultural materials, and construction materials. Specific applications include injection-molded products (e.g., trays for fresh food, fast food containers, coffee capsule containers, cutlery, outdoor leisure products, etc.), extruded products (e.g., films, sheets, fishing lines, fishing nets, vegetation nets, sheets for secondary processing, water-retaining sheets, etc.), and hollow-molded products (bottles, etc.).

[0065] The uses are not limited to those listed above, and it can also be used for mending tape, eyeglass frames, aglets, agricultural films, coating materials, fertilizer coatings, seedling pots, laminate films, boards, stretched sheets, monofilaments, nonwoven fabrics, flat yarns, staples, crimped fibers, crimped tapes, split yarns, composite fibers, blow bottles, shopping bags, garbage bags, compost bags, cosmetic containers, detergent containers, bleach containers, ropes, binding materials, sanitary coverstock materials, insulated boxes, cushioning films, multifilaments, synthetic paper, and for medical use, such as surgical threads, sutures, artificial bones, artificial skin, microcapsules, and wound dressings. [Examples]

[0066] The present invention will be specifically described below with reference to examples and comparative examples. Furthermore, the present invention is not limited to the following embodiments.

[0067] In the embodiments of this application, the acid value and hydroxyl value are values ​​evaluated by the following method. [Method for measuring acid value] Measurements were taken according to the method specified in JIS K0070-1992. [Method for measuring hydroxyl value] Measurements were taken according to the method specified in JIS K0070-1992.

[0068] In the embodiments of this invention, the number-average molecular weight of polyester is a value converted to polystyrene based on GPC measurement, and the measurement conditions are as follows. [GPC measurement conditions] Measurement device: Tosoh Corporation high-speed GPC system "HLC-8320GPC" Columns: Tosoh Corporation's "TSK GURDCOLUMN SuperHZ-L" + Tosoh Corporation's "TSK gel SuperHZM-M" + Tosoh Corporation's "TSK gel SuperHZM-M" + Tosoh Corporation's "TSK gel SuperHZ-2000" + Tosoh Corporation's "TSK gel SuperHZ-2000" Detector: RI (Differential Refractometer) Data processing: EcoSEC Data Analysis version 1.07 manufactured by Tosoh Corporation. Column temperature: 40℃ Developing solvent: tetrahydrofuran Flow rate: 0.35mL / min Measurement sample: 7.5 mg of the sample was dissolved in 10 ml of tetrahydrofuran, and the resulting solution was filtered through a microfilter to be used as the measurement sample. Sample injection volume: 20 μl Standard sample: In accordance with the measurement manual for "HLC-8320GPC" mentioned above, the following monodisperse polystyrenes with known molecular weights were used.

[0069] (Monodisperse polystyrene) "A-300" manufactured by Tosoh Corporation "A-500" manufactured by Tosoh Corporation "A-1000" manufactured by Tosoh Corporation "A-2500" manufactured by Tosoh Corporation "A-5000" manufactured by Tosoh Corporation "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation Tosoh Corporation's "F-10" F-20 manufactured by Tosoh Corporation Tosoh Corporation's "F-40" Tosoh Corporation's "F-80" Tosoh Corporation's "F-128" Tosoh Corporation's "F-288"

[0070] (Synthesis Example 1: Synthesis of Polyester (P1)) In a 1-liter four-necked flask, 202 g of diethylene glycol (hereinafter abbreviated as "DEG") as the glycol component, 337 g of succinic acid (hereinafter abbreviated as "SuA") as the dicarboxylic acid component, 213 g of tetrahydrofurfuryl alcohol (hereinafter abbreviated as "THFA") as the alcohol component, and 0.045 g of tetraisopropyl titanate (hereinafter abbreviated as "TIPT") as the catalyst were charged. The mixture was then heated stepwise to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours, and when the acid value fell below 1.0, unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P1). The obtained polyester (P1) was a pale yellow liquid at room temperature, with an acid value of 0.85, a hydroxyl value of 8, and a number-average molecular weight of 660.

[0071] (Synthesis Example 2: Synthesis of Polyester (P2)) In a 1-liter four-necked flask, 138 g of DEG as the glycol component, 307 g of SuA as the dicarboxylic acid component, 319 g of THFA as the alcohol component, and 0.045 g of TIPT as the catalyst were charged. The mixture was then heated stepwise to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours, and when the acid value fell below 1.0, unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P2). The obtained polyester (P2) was a pale yellow liquid at room temperature, with an acid value of 0.75, a hydroxyl value of 0, and a number-average molecular weight of 480.

[0072] (Synthesis Example 3: Synthesis of Polyester (P3)) In a 1-liter four-necked flask, 99 g of propylene glycol (hereinafter abbreviated as "PG") as the glycol component, 307 g of SuA as the dicarboxylic acid component, 319 g of THFA as the alcohol component, and 0.045 g of TIPT as the catalyst were charged, and the temperature was gradually raised to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours, and when the acid value fell below 1.0, the unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P3). The obtained polyester (P3) was a pale yellow liquid at room temperature, with an acid value of 0.65, a hydroxyl value of 20, and a number-average molecular weight of 400.

[0073] (Synthesis Example 4: Synthesis of Polyester (P4)) In a 1-liter four-necked flask, 138 g of DEG as the glycol component, 380 g of adipic acid (hereinafter abbreviated as "AA") as the dicarboxylic acid component, 319 g of THFA as the alcohol component, and 0.023 g of TIPT as the catalyst were charged, and the temperature was gradually raised to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours, and when the acid value fell below 1.0, the unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P4). The obtained polyester (P4) was a pale yellow liquid at room temperature, with an acid value of 0.77, a hydroxyl value of 4, and a number-average molecular weight of 490.

[0074] (Synthesis Example 5: Synthesis of Polyester (P5)) In a 1-liter four-necked flask, 138 g of DEG as the glycol component, 344 g of glutaric acid as the dicarboxylic acid component, 319 g of THFA as the alcohol component, and 0.023 g of TIPT as the catalyst were charged. The mixture was then heated stepwise to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours, and when the acid value fell below 1.0, unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P5). The obtained polyester (P5) was a pale yellow liquid at room temperature, with an acid value of 0.76, a hydroxyl value of 5, and a number-average molecular weight of 460.

[0075] (Synthesis Example 6: Synthesis of Polyester (P6)) In a 1-liter four-necked flask, 81 g of ethylene glycol (hereinafter abbreviated as "EG") as the glycol component, 380 g of AA as the dicarboxylic acid component, 319 g of THFA as the alcohol component, and 0.023 g of TIPT as the catalyst were charged, and the temperature was gradually raised to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours, and when the acid value fell below 1.0, unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P6). The obtained polyester (P6) was a pale yellow liquid at room temperature, with an acid value of 0.60, a hydroxyl value of 3, and a number-average molecular weight of 450.

[0076] (Synthesis Example 7: Synthesis of Polyester (P7)) In a 1-liter four-necked flask, 79 g of PG (glycol component), 342 g of AA (dicarboxylic acid component), 279 g of THFA (alcohol component), and 0.020 g of TIPT (catalyst) were charged. The mixture was then heated stepwise to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 210°C for 10 to 30 hours. When the acid value fell below 1.0, unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain polyester (P7). The obtained polyester (P7) was a pale yellow liquid at room temperature, with an acid value of 0.80, a hydroxyl value of 7, and a number-average molecular weight of 440.

[0077] (Synthesis Comparison Example 1: Synthesis of diester (D1')) In a 1-liter four-necked flask, 234 g of AA as the dicarboxylic acid component, 199 g of benzyl alcohol and 221 g of methyl carbitol as the alcohol components, and 0.020 g of TIPT as the catalyst were charged, and the temperature was gradually raised to 210°C under a nitrogen stream via a nitrogen inlet tube. The condensation reaction was carried out at 220°C for 10 to 30 hours, and when the acid value fell below 1.0, the unreacted components were removed from the reaction product under reduced pressure at 150°C to obtain the diester (D1'). The resulting diester (D1') was a pale yellow liquid at room temperature, with an acid value of 0.80, a hydroxyl value of 5, and a number-average molecular weight of 330.

[0078] (Synthesis Comparison Example 2: Synthesis of Polyester (P1')) In a 2-liter four-necked flask, 217 g of EG as the glycol component, 14 g of AA as the dicarboxylic acid component, 125 g of butanol as the monoalcohol component, and 0.057 g of TiPT as the catalyst were charged. The mixture was then heated stepwise to 220°C under a nitrogen stream via a nitrogen inlet tube while stirring. The condensation reaction was carried out at 220°C for 13 hours, and when the acid value fell below 1.0, the unreacted components were removed from the reaction product under reduced pressure at 200°C to obtain polyester (P1'). The obtained polyester (P1') was a pale yellow liquid at room temperature, with an acid value of 0.30, a hydroxyl value of 12, and a number-average molecular weight of 1,280.

[0079] (Synthesis Comparison Example 3: Synthesis of Polyester (P2')) In a 2-liter four-necked flask, 83g of EG and 102g of PG were charged as glycol components, 574g of AA as a dicarboxylic acid component, 482g of isononyl alcohol as a monoalcohol component, and 0.062g of TiPT as a catalyst. The mixture was then heated stepwise to 220°C under a nitrogen stream via a nitrogen inlet tube while stirring. The condensation reaction was carried out at 220°C for 13 hours, and when the acid value fell below 1.0, unreacted components were removed from the reaction product under reduced pressure at 200°C to obtain polyester (P2'). The obtained polyester (P2') was a transparent, pale yellow liquid with an acid value of 0.30, a hydroxyl value of 9, and a number-average molecular weight of 1,190.

[0080] (Example 1: Manufacturing and evaluation of cellulose resin molded products) 100 parts by mass of cellulose acetate resin (Daicel Corporation's "L-50") was mixed with 40 parts by mass of polyester (P1) and 0.1 parts by mass of IRGANOX-1076 as a stabilizer, and the mixture was stirred and mixed at a temperature of 70°C or higher. The resulting composition was kneaded using a small melt kneading device (laboplast mill), and 3 mm thick and 60 mm square press plates were produced using a hot press machine. The following evaluations were performed on the obtained press plates. The results are shown in Table 1.

[0081] (1) Transparency The surface of the press sheet was visually inspected, and its transparency was evaluated according to the following criteria. No cloudiness or foreign matter was observed on the surface of the pressed sheet: ○ Cloudiness and / or foreign matter can be observed on the surface of the pressed sheet: ×

[0082] (2) Compatibility after moist heat test The press plates were exposed to a 60°C, 90% relative humidity environment (humid heat environment) for 120 hours. The condition of the press plates after the humid heat test was visually inspected, and the compatibility of the plasticizer was evaluated according to the following criteria. No foreign matter bleed-out was observed on the surface of the press plate: ○ Bleed-out foreign matter can be observed on the surface of the press plate: ×

[0083] (3) Volatility (weight loss after moist heat test) A wet heat test was conducted on the press plate under the same conditions as described in (2) above for compatibility after the wet heat test. The weight of the press plate after 24 hours and after 120 hours of the wet heat test were compared, and the weight loss of the press plate after the wet heat test was evaluated by calculating (mass of press plate after 24 hours - mass of press plate after 120 hours) / mass of press plate after 24 hours of wet heat test. A lower value indicates better non-volatility of the plasticizer in the press plate, which is preferable.

[0084] (4) Melt flow rate (MFR) of the composition For the composition used in the manufacture of the press sheet, the MFR of the composition was measured in accordance with JIS K-7210:1999 at a temperature of 220°C and a load of 10 kg.

[0085] (Examples 2-7 and Comparative Examples 1-5: Manufacturing and Evaluation of Cellulose Resin Molded Products) Press plates were manufactured and evaluated in the same manner as in Example 1, except that the polyester shown in Table 1 was used in the quantities shown in Table 1. The results are shown in Table 1.

[0086] [Table 1]

[0087] In the table, "DAIFATTY-101" refers to a commercially available biodegradable plasticizer for resins (manufactured by Daihachi Chemical Co., Ltd.), and is a dibasic acid ester (diester), not a polyester. Also, "-" in the table indicates that evaluation has not been performed.

[0088] The results in Table 1 show that the polyester plasticizers in the examples have high compatibility with cellulose acetate resin and exhibit sufficient plasticizing effect. On the other hand, the plasticizers in Comparative Examples 1-5, which do not have oxygen-containing heterocycles at the terminals, do not show sufficient compatibility with cellulose acetate resin. Furthermore, in Comparative Examples 1 and 3, which use diesters with only two ester bonds, it can be seen that the non-volatility of the plasticizers is insufficient. Furthermore, the cellulose acetate resin used in the examples has such poor moldability that MFR measurement cannot be performed without the addition of a plasticizer.

[0089] (Example 8: Manufacturing and evaluation of polylactic acid molded products) 100 parts by mass of polylactic acid ("Luminy LX175" manufactured by Total EnergiesCorbion) was mixed with 11.1 parts by mass of polyester (P2) and 0.1 parts by mass of IRGANOX-1010 as a stabilizer, so that the plasticizer content was 10% by mass, and the mixture was stirred and mixed at a temperature of 70°C or higher. The resulting composition was kneaded using a small melt kneading device (laboplast mill), and 3 mm thick and 60 mm square press plates were produced using a hot press machine. The following evaluations were performed on the obtained press plates. The results are shown in Table 2.

[0090] (5) Transparency The surface of the press sheet was visually inspected, and its transparency was evaluated according to the following criteria. No cloudiness or foreign matter was observed on the surface of the pressed sheet: ○ Cloudiness and / or foreign matter can be observed on the surface of the pressed sheet: ×

[0091] (6) Compatibility after moist heat test The press plates were exposed to an environment of 85°C and 90% relative humidity (humid heat environment) for 6 hours. The condition of the press plates after the humid heat test was visually inspected, and the compatibility of the plasticizer was evaluated according to the following criteria. No foreign matter bleed-out was observed on the surface of the press plate: ○ Bleed-out foreign matter can be observed on the surface of the press plate: ×

[0092] (7) Melt flow rate (MFR) of the composition For the composition used in the manufacture of the press plate, the MFR of the composition was measured in accordance with JIS K-7210:1999 at a temperature of 190°C and a load of 2.16 kg.

[0093] (Example 9 and Comparative Example 6: Production and evaluation of polylactic acid molded products) Press plates were manufactured and evaluated in the same manner as in Example 8, except that the polyester shown in Table 2 was used in the quantities shown in Table 2. The results are shown in Table 2. Note that no plasticizer was added in Comparative Example 6.

[0094] [Table 2]

[0095] The results in Table 2 show that the polyester plasticizer in the examples has high compatibility not only with cellulose acetate resin but also with polylactic acid, and exhibits a sufficient plasticizing effect.

Claims

1. A plasticizer for biodegradable resins, which is a polyester represented by the following general formula (1). 【Chemistry 1】 (In the above general formula (1), B １１ and B １２ These are, independently, alcohol residues of a monoalcohol having an oxygen-containing heterocycle. A is independently an alkylenedicarboxylic acid residue having 2 to 12 carbon atoms or an aryldicarboxylic acid residue having 6 to 18 carbon atoms. G is an alkylene glycol residue having 2 to 12 carbon atoms or an oxyalkylene glycol residue having 4 to 12 carbon atoms. n represents the number of repetitions.

2. The biodegradable plasticizer for resins according to claim 1, wherein the alcohol residue of the monoalcohol having an oxygen-containing heterocycle is a tetrahydrofurfuryl alcohol residue.

3. The biodegradable plasticizer for resins according to claim 1, wherein A is a succinic acid residue, a glutaric acid residue, an adipic acid residue, a sebacic acid residue, or an azelaic acid residue.

4. The biodegradable plasticizer for resins according to claim 1, wherein G is an ethylene glycol residue, a 1,2-propylene glycol residue, a 1,3-propanediol residue, a 1,2-butanediol residue, a 1,3-butanediol residue, a 2-methyl-1,3-propanediol residue, a neopentyl glycol residue, a diethylene glycol residue, or a dipropylene glycol residue.

5. The biodegradable plasticizer for resins according to claim 1, wherein the polyester is a polyester obtained by reacting with a monoalcohol having an oxygen-containing heterocycle, an alkylenedicarboxylic acid having 4 to 14 carbon atoms and / or an aryldicarboxylic acid having 8 to 20 carbon atoms, and an alkylene glycol having 2 to 12 carbon atoms and / or an oxyalkylene glycol having 4 to 12 carbon atoms as reaction materials.

6. The biodegradable resin plasticizer according to claim 1, wherein the number average molecular weight of the polyester is in the range of 300 to 3,000.

7. A plasticizer for cellulose ester resins according to any one of claims 1 to 6.

8. A biodegradable resin composition comprising a biodegradable resin plasticizer and a biodegradable resin according to any one of claims 1 to 6, wherein the biodegradable resin composition contains the biodegradable resin plasticizer in an amount of 1 to 100 parts by mass per 100 parts by mass of the biodegradable resin.

9. The biodegradable resin composition according to claim 8, wherein the biodegradable resin is one or more selected from the group consisting of cellulose ester resin, polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polyhydroxybutyrate-hydroxyhexanoic acid, polyhydroxybutyrate-hydroxyvalate, polybutylene succinate adipate, and polyethylene terephthalate succinate.

10. A molded article of the biodegradable resin composition according to claim 8.

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