Resin plasticizer and resin composition

Abstract

A polyester obtained by reacting the following components (A)-(C). (A) A dicarboxylic acid represented by general formula (1) or an acid anhydride thereof. (B) A trialkylene glycol having an optionally branched C1-8 alkylene group. (C) An alcohol represented by general formula (2).

Description

Plasticizer for resin and resin composition

[0001] The present invention relates to a novel polyester and a resin composition containing the same.

[0002] Plastics such as polyester, polyolefin, polyamide, polyacetal, vinyl resin, styrene-based resin, acrylic resin, and cellulose-based resin are used in a wide range of fields, including food packaging, construction materials, and home appliances. In addition, various plasticizers are used to impart flexibility and other properties to these plastics, and plastic products with improved functionality are used in a variety of applications.

[0003] As examples of plastic products containing such plasticizers, Patent Document 1 describes a polyester-based plasticizer having a structure in which both ends of a polymer chain having repeating units of an aliphatic dicarboxylic acid and a diol are blocked with an aliphatic monoalcohol, a polyester resin composition containing the plasticizer, and a sheet and film made of the resin composition. It is disclosed that these products have good transparency, heat resistance, and bleeding resistance due to the inclusion of the polyester-based plasticizer.

[0004] JP 2013-199637 A

[0005] However, the above-mentioned polyester plasticizers still do not have sufficient bleeding resistance. An object of the present invention is to provide a polyester plasticizer with even better bleeding resistance.

[0006] The present inventors have conducted extensive research to solve the above-mentioned problems, and as a result have found that a polyester (plasticizer) obtained by reacting a specific dicarboxylic acid, a diol, and a monoalcohol, which will be described later, has excellent bleeding resistance and can solve the above-mentioned problems, thereby completing the present invention.

[0007] [1] A polyester obtained by the reaction of the following components (A) to (C): (A) a polyester represented by the following general formula (1):

[0008] (In the formula, R １(B) a dicarboxylic acid or an acid anhydride thereof having an alkylene group having 1 to 8 carbon atoms, which may be branched. (C) a dicarboxylic acid or an acid anhydride thereof represented by the following general formula (2):

[0009] (In the formula, R ２ is an alkyl group having 1 to 4 carbon atoms which may be branched or a phenoxy group, and n is an integer of 0 to 2. When n is 2, there are multiple R ２ may be the same or different.) Alcohols represented by the formula:

[0010] [2] The polyester according to [1], wherein in component (B), the trialkylene glycol having an alkylene group having 1 to 8 carbon atoms, which may have a branch, is at least one trialkylene glycol selected from the group consisting of triethylene glycol, tripropylene glycol, and trimethylene glycol.

[0011] [3] A resin composition comprising the polyester according to [1] or [2] and a resin other than the polyester.

[0012] [4] The resin composition according to [3], wherein the other resin is a biodegradable resin.

[0013] [5] The resin composition according to [3], wherein the other resin is a polylactic acid-based resin.

[0014] According to the present invention, a polyester (plasticizer) having excellent bleeding resistance can be provided. Furthermore, when the polyester of the present invention is added to a resin (e.g., a polylactic acid-based resin), the resulting resin composition exhibits effects of little bleeding out (i.e., excellent bleeding resistance) and excellent transparency and plasticity.

[0015] The present invention will be described in detail below. In this specification, when a numerical range is expressed as "A to B," it means A or more and B or less. In addition, in this specification, the term "comprise" is a concept that also encompasses "consist essentially of" and "consist only of."

[0016] [Polyester] The polyester of the present invention is obtained by the reaction of the following components (A) to (C), and can be used as a plasticizer as it is. (A) A polyester represented by the following general formula (1):

[0017] (In the formula, R １ (B) a dicarboxylic acid or an acid anhydride thereof having an alkylene group having 1 to 8 carbon atoms, which may be branched. (C) a dicarboxylic acid or an acid anhydride thereof represented by the following general formula (2):

[0018] (In the formula, R ２ is an alkyl group having 1 to 4 carbon atoms which may be branched or a phenoxy group, and n is an integer of 0 to 2. When n is 2, there are multiple R ２ may be the same or different.) Alcohols represented by the formula:

[0019] The polyester of the present invention is a polyester containing the structural unit (a) derived from the component (A), the structural unit (b) derived from the component (B), and the structural unit (c) derived from the component (C), and typically consists essentially of the structural units (a), (b), and (c). The polyester of the present invention is a copolymer of the component (A) which is a dicarboxylic acid component and the component (B) which is a diol component, and has a structure in which at least one polymer end is blocked with the component (C).

[0020] Component (A) is a dicarboxylic acid represented by the above general formula (1) or an acid anhydride thereof. １ is an alkylene group having 1 to 12 carbon atoms, which may be branched. １ Examples of the alkylene group having 1 to 12 carbon atoms, which may have a branch, include an ethylene group, a propylene group, a trimethylene group, and a tetramethylene group. １is preferably an alkylene group having 1 to 8 carbon atoms which may be branched, more preferably an alkylene group having 1 to 4 carbon atoms which may be branched, and further preferably an ethylene group or a tetramethylene group. １ When a polyester obtained using a dicarboxylic acid (e.g., maleic acid, fumaric acid, etc.) in which the alkylene group is an alkenylene group or an anhydride thereof is used as a resin composition described below, it is not preferable because it may not only plasticize other resins but may also react with them to harden them.

[0021] Specific examples of component (A) include malonic acid, methylmalonic acid, ethylmalonic acid, dimethylmalonic acid, succinic acid, methylsuccinic acid, 2,2-dimethylsuccinic acid, 2,2,3-trimethylsuccinic acid, 2-ethyl-2-methyl-succinic acid, glutaric acid, 2-methylglutaric acid, 2,2-dimethylglutaric acid, 2,4-dimethylglutaric acid, 3,3-dimethylglutaric acid, 3-ethyl-3-methylglutaric acid, adipic acid, 3-methyladipic acid, 2,2-dimethyladipic acid, pime Examples thereof include phosphoric acid, suberic acid, azelaic acid, heptane-4,4-dicarboxylic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, brassylic acid, tetradodecanedioic acid, 1,1-cyclopropanedicarboxylic acid, 1,1-cyclobutanedicarboxylic acid, 1,3-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,1-cyclopentanediacetic acid, and acid anhydrides thereof. These may be used alone or in combination of two or more.

[0022] Component (B) is a trialkylene glycol having an optionally branched alkylene group having 1 to 8 carbon atoms. Examples of the optionally branched alkylene group having 1 to 8 carbon atoms include an ethylene group, a propylene group, and a trimethylene group. Among these, an optionally branched alkylene group having 1 to 4 carbon atoms is preferred, and an ethylene group, a propylene group, or a trimethylene group is more preferred.

[0023] Specific examples of component (B) include triethylene glycol, tripropylene glycol, trimethylene glycol, etc. These may be used alone or in combination of two or more.

[0024] Component (C) is an alcohol represented by the above general formula (2). In the above general formula (2), R ２ is an optionally branched alkyl group having 1 to 4 carbon atoms or a phenoxy group. Examples of the optionally branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, an isobutyl group, and a tert-butyl group. Of these substituents, a methyl group is preferred.

[0025] In the above general formula (2), n is an integer of 0 to 2, preferably 0 or 1. When n is 2, a plurality of R ２ may be the same or different.

[0026] Specific examples of component (C) include benzyl alcohol (n=0), 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 2-ethylbenzyl alcohol, 3-ethylbenzyl alcohol, 4-ethylbenzyl alcohol, 2,3-dimethylbenzyl alcohol, 2,4-dimethylbenzyl alcohol, 3,5-dimethylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 4-isopropylbenzyl alcohol, 2,4,6-trimethylbenzyl alcohol, 3,4,5-trimethylbenzyl alcohol, 3-phenoxybenzyl alcohol, etc. These may be used alone or in combination of two or more.

[0027] The polyester of the present invention has, for example, a number average molecular weight of 300 to 10,000, preferably 350 to 4,000, and more preferably 400 to 2,000. The number average molecular weight can be measured, for example, by the method described in the Examples section below.

[0028] [Method for Producing Polyester] The polyester of the present invention can be obtained, for example, by subjecting the above components (A) to (C) to an esterification reaction using a conventional method. Examples of reaction methods include a single-stage method in which the above components (A) to (C) are reacted simultaneously, and a multi-stage method in which component (A) is reacted with component (B) and then component (C) is reacted. Multi-stage methods are preferred. The reaction is carried out, for example, at a temperature of 100°C to 300°C, in the presence of an acid and / or catalyst as needed, and in the presence of a solvent such as toluene or xylene, while removing the generated water from the system. The reaction is preferably carried out under an inert gas atmosphere such as nitrogen or helium, or under a stream of air. The product obtained by the reaction may be distilled to remove unreacted raw materials, by-products, solvent, etc., using conventional methods, and may also be purified by washing, adsorption, etc.

[0029] The molar ratio of the components (A) to (C) during the reaction is, for example, 1.0 mole of the component (A), 0.3 to 0.9 moles of the component (B), and 0.2 to 3.0 moles of the component (C).

[0030] [Resin Composition] The resin composition of the present invention contains the polyester of the present invention described above and a resin. Examples of the resin include polyester resins other than the polyester of the present invention, polyolefin resins, polyamide resins, polyacetal resins, vinyl resins, styrene-based resins, and acrylic resins.

[0031] Examples of the polyolefin resin include olefin homopolymers such as polyethylene, polypropylene, poly-1-butene, polymethylpentene, and polymethylbutene, and olefin copolymers such as propylene-ethylene random copolymers.

[0032] Examples of the polyamide resin include aliphatic polyamides such as nylon-6, nylon-66, nylon-10, nylon-12, and nylon-46, and aromatic polyamides produced from aromatic dicarboxylic acids and aliphatic diamines.

[0033] Examples of the polyacetal resin include polyformaldehyde, polyacetaldehyde, polypropionaldehyde, and polybutylaldehyde.

[0034] Examples of the vinyl resin include homopolymers such as polyvinyl chloride and polyvinylidene chloride, and vinyl compound copolymers such as copolymers of vinyl chloride or vinylidene chloride with vinyl acetate.

[0035] Examples of the styrene-based resin include polystyrene, AS resin, and ABS resin.

[0036] Examples of the acrylic resin include polyacrylic ester and polymethyl methacrylate.

[0037] Examples of the other polyester resins include aromatic polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; aliphatic aromatic copolyesters such as polybutylene succinate / terephthalate, polybutylene adipate / terephthalate, and polytetramethylene adipate / terephthalate; polycaprolactone, polyhydroxybutyrate (PHB), poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV), and poly(hydroxybutyrate-co-hydroxyhexamethyl). Examples of the polyhydroxyalkanoate include polyhydroxyalkanoates (PHAs) such as polybutylene succinate, polybutylene succinate-adipate copolymer, polyethylene succinate, polylactic acid resins, polymalic acid, polyglycolic acid, polydioxanone, and poly(2-oxetanone); and mixtures of natural polymers such as starch, cellulose, chitin, chitosan, gluten, gelatin, zein, soybean protein, collagen, and keratin with the above-mentioned aliphatic polyesters or aliphatic aromatic copolyesters.

[0038] Among these resins, polyester resins that are decomposed into low molecular weight compounds in nature with the involvement of microorganisms (biodegradable) based on JIS K6953 (ISO14855) "Test for aerobic and ultimate biodegradability and disintegration under controlled aerobic compost conditions" are preferred, biodegradable aliphatic polyesters are more preferred, and polylactic acid resins are particularly preferred.

[0039] The polylactic acid resin is not particularly limited as long as it is a polyester resin obtained by polymerizing lactic acid, and examples thereof include a polylactic acid homopolymer, copolymer, blend polymer, etc. Examples of copolymers include copolymers of lactic acid with hydroxycarboxylic acids such as glycolic acid, hydroxypropionic acid, hydroxyheptanoic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, and hydroxybenzoic acid, dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, glutaric acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, and anthracenedicarboxylic acid, polyhydric alcohols such as ethylene glycol, propylene glycol, butanediol, octanediol, dodecanediol, neopentyl glycol, glycerin, pentaerythritol, sorbitan, bisphenol A, and polyethylene glycol, and lactones such as glycolide, caprolactone, butyrolactone, valerolactone, propylolactone, and undecalactone. Examples of blend polymers include mixtures of polylactic acid homopolymers and / or copolymers with celluloses, glycogen, chitin, chitosan, etc. The lactic acid used in the polymerization may be L-lactic acid, D-lactic acid, or a mixture thereof. These resins listed as resins contained in the resin composition of the present invention may be used alone or in combination of two or more.

[0040] In the resin composition of the present invention, the content of the polyester of the present invention is, for example, 1 to 100 parts by weight, preferably 1 to 50 parts by weight, and more preferably 5 to 30 parts by weight, per 100 parts of resin.

[0041] In the present invention, the method for blending the ester compound of the present invention with a resin is not particularly limited, and examples thereof include a method of mixing using a blender, a mixer, etc., and a method of melt-kneading using an extruder, a Banbury mixer, a kneader, etc. Alternatively, a plasticizer may be mixed into the resin from the resin production stage.

[0042] In addition to the polyester of the present invention and the above-described resin, the resin composition of the present invention may contain other additives such as antiblocking agents, lubricants, antistatic agents, antifogging agents, ultraviolet absorbers, heat stabilizers, antioxidants, coloring inhibitors, fillers, pigments, dyes, dispersants, and flame retardants, depending on the intended use, within the scope of not impairing the object of the present invention. Furthermore, a compound generally used as a plasticizer other than the polyester of the present invention may also be used in combination.

[0043] The resin composition of the present invention can be molded using extrusion molding, injection molding, stretch film molding, blow molding, and other molding methods, just like general thermoplastic plastics, and is therefore useful in a wide range of applications, including food containers, electrical parts, electronic parts, automotive parts, medical materials, film and sheet materials, fiber materials, paint resins, ink resins, toner resins, and adhesive resins.

[0044] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The number average molecular weights of the polyesters described in the examples are polystyrene-equivalent number average molecular weights measured by gel permeation chromatography (GPC) according to the measurement method described below.

[0045] Example 1: 445.1 g (3.03 mol) of adipic acid, 229.8 g (1.52 mol) of triethylene glycol, 153 g of toluene, 12.0 g of paratoluenesulfonic acid monohydrate, and 2.5 g of sodium hypophosphite monohydrate were placed in a four-neck flask equipped with a stirrer, a nitrogen inlet tube, a thermometer, and a condenser. The mixture was heated to 110-120°C and subjected to an esterification reaction while removing the generated water from the system. After the theoretical amount of water was produced, 339.3 g (3.11 mol) of benzyl alcohol was added, the mixture was heated to 120-130°C, and the esterification reaction was continued under reduced pressure until the theoretical amount of water was produced. The mixture was cooled to 80°C, neutralized with a 24% aqueous sodium hydroxide solution, and washed with water. Then, toluene and excess alcohol were removed under reduced pressure, followed by washing with an alkali and washing with water, and the water was removed under reduced pressure to obtain 827.9 g of a polyester (reaction product A) having a number average molecular weight of 495.

[0046] Comparative Synthesis Example 1 Using a reaction apparatus similar to that used in Example 1, 268.0 g (2.27 mol) of succinic acid, 171.3 g (1.14 mol) of triethylene glycol, 95 g of toluene, 14.0 g of paratoluenesulfonic acid monohydrate, and 3.2 g of sodium hypophosphite monohydrate were added, and an esterification reaction was carried out at 110 to 120°C while removing the produced water from the system. After the theoretical amount of water was produced, 253.6 g (3.42 mol) of normal butanol was added, and the mixture was heated to 100 to 120°C. The esterification reaction was continued until the theoretical amount of water was produced. The mixture was cooled to 80°C, neutralized with a 24% aqueous sodium hydroxide solution, and washed with water. Next, toluene and excess alcohol were removed under reduced pressure, followed by alkali washing and water washing, and the water was removed under reduced pressure to obtain 332.3 g of a polyester (reaction product B) having a number average molecular weight of 778.

[0047] Comparative Synthesis Example 2 Using the same reaction apparatus as in Example 1, 236.9 g (1.62 mol) of adipic acid, 161.3 g (0.81 mol) of polyethylene glycol #200 (average degree of polymerization n = 4), 102 g of toluene, 10.1 g of paratoluenesulfonic acid monohydrate, and 2.1 g of sodium hypophosphite monohydrate were added, and an esterification reaction was carried out at 110 to 120 °C while removing the produced water from the system. After the theoretical amount of water was produced, 269.3 g (1.66 mol) of diethylene glycol monobutyl ether was added, and the mixture was heated to 120 to 130 °C. The esterification reaction was continued until the theoretical amount of water was produced. The mixture was cooled to 80 °C, neutralized with a 24% aqueous sodium hydroxide solution, and washed with water. Next, toluene and excess alcohol were removed under reduced pressure, followed by alkali washing and water washing, and the water was removed under reduced pressure to obtain 522.1 g of a polyester (reaction product C) having a number average molecular weight of 966.

[0048] Comparative Synthesis Example 3 Using the same reaction apparatus as in Example 1, 476.1 g (4.02 mol) of succinic acid, 125.3 g (2.01 mol) of ethylene glycol, 159 g of toluene, 6.3 g of paratoluenesulfonic acid monohydrate, and 1.3 g of sodium hypophosphite monohydrate were added, and an esterification reaction was carried out at 110 to 120°C while removing the produced water from the system. After the theoretical amount of water was produced, 449.9 g (4.12 mol) of benzyl alcohol was added, and the mixture was heated to 120 to 130°C. The esterification reaction was continued until the theoretical amount of water was produced. The mixture was cooled to 80°C, neutralized with a 24% aqueous NaOH solution, and washed with water. Next, toluene and excess alcohol were removed under reduced pressure, followed by alkali washing and water washing, and the water was removed under reduced pressure to obtain 761.5 g of a polyester (reaction product D) having a number average molecular weight of 343.

[0049] [Number Average Molecular Weight Measurement] Using polystyrene of known molecular weight as a standard substance, the number average molecular weight was measured by GPC under the following conditions: Instrument used: HLC-8320 (manufactured by Tosoh Corporation) Columns: TSKgel Super HZ1000 + TSKgel Super HZ2500 + TSKgel Super HZ4000 + TSKgel guard column Super HZ-L, one each in series Solvent (carrier): THF (tetrahydrofuran) Flow rate: 0.350 mL / min Column temperature: 40°C Detector: RI Injection volume: 10 μL Sample preparation: Approximately 0.1 g of the polyester to be measured was dissolved in 5 mL of THF. Method for calculating number average molecular weight (Mn): The multimodal peaks obtained by the GPC measurement were treated as a single group, and the peaks corresponding to the organic solvent were excluded to calculate the number average molecular weight (Mn) of the polyester.

[0050] Example 2 and Comparative Examples 1 to 6 A plasticizer was added to 100 parts by weight of a polylactic acid (PLA) resin (Ingeo 4032D (Nature Works)) as shown in Table 1, and the mixture was melt-kneaded using a Labo Plastomill (Toyo Seiki Seisaku-Sho, Ltd.) at a set temperature of 190°C to obtain a resin composition. This resin composition was compression-molded at 180°C and a cooling temperature of 25°C to prepare a test sheet with a thickness of approximately 1 mm. Performance evaluation was carried out using this test sheet under the conditions described below. The evaluation results are summarized in Table 1.

[0051] [Transparency Evaluation] A test sheet having a thickness of approximately 1 mm was left for 24 hours in an environment of 23°C and 50% humidity, and then the haze value of the test film was measured using a haze meter NDH4000 (manufactured by Nippon Denshoku Industries Co., Ltd.) Note that if the haze value is equal to or lower than that of Comparative Example 1 (no plasticizer added), it indicates that the inherent transparency of the polylactic acid resin is not impaired and the transparency is excellent.

[0052] [Plasticity Evaluation] A test sheet approximately 1 mm thick was punched out using a No. 3 dumbbell, and the dumbbell was left standing in a thermostatic chamber at 23°C and 50% RH for 24 hours. After that, a tensile test was performed at a pulling rate of 200 mm / min, and the tensile breaking elongation (%) was calculated from the elongation at which the sample broke. Note that a larger value for the tensile breaking elongation (%) indicates higher plasticity.

[0053] [Bleeding property evaluation] A test sheet with a thickness of about 1 mm was prepared, and the weight of the sheet was measured. Then, the test sheet was left standing in an atmosphere of 80°C for 24 hours, and the plasticizer that bled out from the surface of the test sheet was wiped off, and the weight of the test sheet was measured, and the weight loss rate was calculated from the weight before and after the test. Note that a smaller weight loss rate indicates higher bleeding resistance.

[0054]

[0055] ATBC: acetyl tributyl citrate (manufactured by Taoka Chemical Co., Ltd.) SR-86A: butoxyethoxyethyl adipate (manufactured by Taoka Chemical Co., Ltd.)

Claims

1. A polyester obtained by the reaction of the following components (A) to (C): (A) a polyester represented by the following general formula (1): (In the formula, R １ (B) a dicarboxylic acid or an acid anhydride thereof having an alkylene group having 1 to 8 carbon atoms, which may be branched. (C) a dicarboxylic acid or an acid anhydride thereof represented by the following general formula (2): (In the formula, R ２ is an alkyl group having 1 to 4 carbon atoms which may be branched or a phenoxy group, and n is an integer of 0 to 2. When n is 2, there are multiple R ２ may be the same or different.) Alcohols represented by the formula:

2. The polyester according to claim 1, wherein in component (B), the trialkylene glycol having an alkylene group having 1 to 8 carbon atoms, which may be branched, is at least one trialkylene glycol selected from the group consisting of triethylene glycol, tripropylene glycol, and trimethylene glycol.

3. A resin composition comprising the polyester according to claim 1 or 2 and a resin other than said polyester.

4. The resin composition according to claim 3, wherein the other resin is a biodegradable resin.

5. The resin composition according to claim 3, wherein the other resin is a polylactic acid resin.

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