Resin composition

Abstract

To provide a resin composition which has improved impact resistance at low temperature.SOLUTION: A resin composition contains a 3-hydroxyalkanoic acid-based polymer represented by formula (I), and a polyester-based polymer, wherein the polyester-based polymer is composed of a monomer unit composed of only a polyhydric alcohol component and a dicarboxylic acid component, at least a part of a terminal of the polyester-based polymer is sealed with a residue of monoalcohol and / or a residue of a monocarboxylic acid, polyhydric alcohol of the polyhydric alcohol component is MPD(3-methyl-1,5-pendandiol) and / or TMP(trimethylol propane), a dicarboxylic acid of the dicarboxylic acid component is an adipic acid or a sebacic acid, the monoalcohol is 2-ethylhexanol, and the monocarboxylic acid is an acetic acid. In the formula (I), a ratio (k / p) is 70 / 30 to 99 / 1.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a resin composition. [Background technology]

[0002] In recent years, due to the demand for environmentally friendly, sustainable biomass resins and biodegradable resins, development of these resins has been actively carried out. Under these circumstances, polyhydroxyalkanoic acid polymers, which are biomass and biodegradable resins, are used in a wide range of fields, such as packaging, food service, biomedical, and agriculture. However, polyhydroxyalkanoic acid polymers are generally known to be more brittle than petroleum-based resins and to have poorer flexibility (elongation) and impact resistance. Therefore, the use of polyhydroxyalkanoic acid polymers as resin materials is sometimes limited. Under these circumstances, attempts to improve the physical properties of biomass resins and biodegradable resins have been made, for example, to impart flexibility while suppressing bleed-out (see, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-023091 [Patent Document 2] International Publication No. 2023 / 026758 Summary of the Invention [Problem to be solved by the invention]

[0004] However, Patent Documents 1 and 2, including the examples, only mainly consider polylactic acid polymers as biomass resins and biodegradable resins, and do not specifically or sufficiently consider polyhydroxyalkanoic acid polymers, particularly 3-hydroxyalkanoic acid polymers, from the viewpoint of imparting impact resistance at low temperatures, etc.

[0005] In view of the above, an object of the present invention is to provide a resin composition having improved impact resistance at low temperatures. [Means for solving the problem]

[0006] As a result of intensive research to solve the above problems, the present inventors have conceived the following invention and found that the problems can be solved. That is, the present invention is as follows.

[0007] [1] A resin composition comprising a 3-hydroxyalkanoic acid polymer represented by the following formula (I) and a polyester polymer, [ka] (In formula (I), the ratio of k to p (k / p) is 70 / 30 to 99 / 1.) The polyester polymer is It is composed of monomer units consisting only of polyhydric alcohol components and dicarboxylic acid components. At least a portion of the ends of the polyester polymer are blocked with a residue of a monoalcohol and / or a residue of a monocarboxylic acid, The polyhydric alcohol of the polyhydric alcohol component is MPD (3-methyl-1,5-pentanediol) and / or TMP (trimethylolpropane), the dicarboxylic acid of the dicarboxylic acid component is adipic acid or sebacic acid; the monoalcohol is 2-ethylhexanol; The resin composition, wherein the monocarboxylic acid is acetic acid. [2] The resin composition according to the above [1], which contains 5 to 30 parts by mass of the polyester polymer per 100 parts by mass of the 3-hydroxyalkanoic acid polymer. [3] The resin composition according to the above [1] or [2], wherein the weight-average molecular weight of the 3-hydroxyalkanoic acid polymer is 50,000 to 3,000,000. [4] The resin composition according to any one of the above [1] to [3], wherein the ratio of the molar amount of MPD to the total amount of the molar amount of MPD and the molar amount of TMP contained in the polyester polymer is 0.20 to 1.00, and the ratio of the molar amount of TMP to the total amount of the molar amount of MPD and the molar amount of TMP is 0 to 0.80. [5] The resin composition according to any one of the above [1] to [4], wherein the polyester polymer has a hydroxyl value of 20 mgKOH / g or less and an acid value of 15 mgKOH / g or less. [6] The resin composition according to any one of the above [1] to [5], wherein the polyester polymer has a number average molecular weight of 300 to 4,000. [7] The resin composition according to any one of the above [1] to [6], wherein the polyhydric alcohol contained in the polyester polymer is the MPD and the TMP. [8] The resin composition according to any one of the above [1] to [6], wherein the polyhydric alcohol contained in the polyester polymer is the MPD. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a resin composition having improved impact resistance at low temperatures. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present invention will be described below based on an example of an embodiment, but the embodiment shown below is merely an example for embodying the technical concept of the present invention, and the present invention is not limited to the following description. In this specification, preferred embodiments are shown, but a combination of two or more of the individual preferred embodiments is also a preferred embodiment. When there are several numerical ranges for matters shown as numerical ranges, the lower limit and upper limit can be selectively combined to form a preferred embodiment. Furthermore, when a numerical range is described as "XX to YY," it means "XX or more and YY or less." In this specification, the term "unit" (where "" indicates a polymer) means a "structural unit derived from". For example, a "monomer unit" means a "structural unit derived from a monomer".

[0010] [Resin composition] The resin composition of the present embodiment contains a 3-hydroxyalkanoic acid polymer represented by the following formula (I) and a polyester polymer. [ka] (In formula (I), the ratio of k to p (k / p) is 70 / 30 to 99 / 1.) The polyester polymer is composed of monomer units consisting only of polyhydric alcohol components and dicarboxylic acid components, and at least a portion of the terminals of the polyester polymer are blocked with a monoalcohol residue and / or a monocarboxylic acid residue. The polyhydric alcohol of the polyhydric alcohol component is MPD (3-methyl-1,5-pentanediol) and / or TMP (trimethylolpropane), and the dicarboxylic acid of the dicarboxylic acid component is adipic acid or sebacic acid. The monoalcohol is 2-ethylhexanol and the monocarboxylic acid is acetic acid. As a result of extensive investigations, the present inventors have found that a resin composition containing a 3-hydroxyalkanoic acid polymer and a specific polyester polymer can improve impact resistance at low temperatures.

[0011] The reason why the resin composition of the present embodiment has good elongation and impact resistance at low temperatures is not clear, but is presumed to be as follows. Since the polyester polymer contains an ester structure, it tends to have a suitable compatibility with the 3-hydroxyalkanoic acid polymer, which also contains an ester structure. Furthermore, by ester-modifying the terminal hydroxyl groups of the amorphous, flexible polyester polymer with a low glass transition temperature (Tg), it is believed that compatibility with the 3-hydroxyalkanoic acid polymer is further enhanced, improving elongation and impact resistance at low temperatures. In the present invention, amorphous refers to a polyester polymer that has been melted, dried, and kept at room temperature for 5 to 10 days, and then cooled using a differential scanning calorimeter (DSC) to a temperature of -50°C or lower, preferably -100°C or lower, at a rate of -10°C / min or faster, and then kept at that temperature for 5 to 15 minutes. When the DSC is then measured again at a temperature rising rate of 10°C / min up to a temperature at which melt processing is possible, preferably a temperature of 150°C or higher, no peak of at least 0.5 J / 40 g is observed other than a change in heat capacity due to glass transition. The glass transition temperature Tg of the polyester polymer is preferably −40° C. or lower, more preferably −50° C. or lower, and even more preferably −60° C. or lower.

[0012] <3-hydroxyalkanoic acid polymer> The 3-hydroxyalkanoic acid polymer of this embodiment is represented by the following general formula (I).

[0013] [ka]

[0014] 〈k / p〉 The ratio of k to p (k / p) represents the ratio of each structural unit and is 70 / 30 to 99 / 1. When k / p is 70 / 30 or more, a molded article produced using the resin composition has sufficient strength and is highly practical, and when k / p is 99 / 1 or less, the resin composition exhibits good impact resistance. In this specification, "k and p" are values ​​determined by gas chromatography measurement using the following method. To 20 mg of a 3-hydroxyalkanoic acid polymer, 2 mL of a sulfuric acid-methanol mixture (volume ratio 15:85) and 2 mL of chloroform were added, sealed, and heated at 100°C for 140 minutes to obtain the methyl ester of the 3-hydroxyalkanoic acid polymer decomposition product. After cooling, 1.5 g of sodium bicarbonate was added little by little to neutralize the mixture, and the mixture was left to stand until carbon dioxide generation ceased. Next, 4 mL of diisopropyl ether was added and mixed well, followed by centrifugation. The monomer unit composition ratio of the polyester decomposition product in the supernatant was analyzed under the following measurement conditions. (Measurement conditions) Equipment: Gas chromatograph GC-17A (Shimadzu Corporation) Capillary column: NEUTRA BOND-1 (GL Sciences, column length 25 m, column inner diameter 0.25 mm, liquid film thickness 0.4 μm)

[0015] <Number average molecular weight (Mn)> The number average molecular weight of the 3-hydroxyalkanoic acid polymer is preferably 20,000 to 1,000,000, and more preferably 50,000 to 700,000. When the number average molecular weight is within the above range, the viscosity of the resin composition is prevented from becoming too low or too high, improving the handling properties and productivity during molding.

[0016] <Weight average molecular weight (Mw)> The weight-average molecular weight of the 3-hydroxyalkanoic acid polymer is preferably 50,000 to 3,000,000, and more preferably 100,000 to 1,500,000. When the weight-average molecular weight is within the above range, the viscosity of the resin composition is prevented from becoming too low or too high, improving the handling properties and productivity during molding.

[0017] <Molecular weight distribution (Mw / Mn)> The molecular weight distribution (Mw / Mn) of the 3-hydroxyalkanoic acid polymer is preferably 1.0 to 3.0, more preferably 1.1 to 2.0, and even more preferably 1.2 to 1.8.

[0018] <Polyester polymer> The polyester polymer is composed of monomer units consisting only of a polyhydric alcohol component and a dicarboxylic acid component, and the terminals are capped with a residue of a monoalcohol and / or a residue of a monocarboxylic acid, or the terminals are capped with at least one residue selected from the residues of the monoalcohol and the residues of the monocarboxylic acid, and via monomer units consisting only of the polyhydric alcohol component and the dicarboxylic acid component. Specifically, for example, the ends may be capped only with acetic acid residues or only with 2-ethylhexanol residues. Furthermore, a part of the terminals may not be blocked with the residue of the monoalcohol or the residue of the monocarboxylic acid.

[0019] The polyhydric alcohol of the polyhydric alcohol component is MPD (3-methyl-1,5-pentanediol) and / or TMP (trimethylolpropane).

[0020] The dicarboxylic acid of the dicarboxylic acid component is adipic acid or sebacic acid.

[0021] The monoalcohol is 2-ethylhexanol and the monocarboxylic acid is acetic acid.

[0022] In an embodiment, the polyhydric alcohol contained in the polyester polymer is preferably MPD or TMP.

[0023] In another embodiment, the polyhydric alcohol contained in the polyester polymer is preferably MPD.

[0024] In still another embodiment, from the viewpoint of exhibiting even better biodegradability, it is preferable that only monomer units containing the above-mentioned polyhydric alcohol (MPD) component and dicarboxylic acid (adipic acid or sebacic acid) component exist, or that monomer units containing the above-mentioned polyhydric alcohol (MPD) component and dicarboxylic acid (adipic acid or sebacic acid) component and monomer units containing the above-mentioned polyhydric alcohol (TMP) component and dicarboxylic acid (adipic acid or sebacic acid) component coexist in the polyester polymer.

[0025] The ratio of the molar amount of MPD to the total amount of the molar amounts of MPD and TMP contained in the polyester polymer is preferably 0.20 to 1.00, and the ratio of the molar amount of TMP to the total amount of the molar amounts of MPD and TMP is preferably 0 to 0.80. When the ratio of the molar amount of MPD and the molar amount of TMP are within these ranges, impact resistance at low temperatures is easily exhibited.

[0026] In an embodiment, from the viewpoint of storage stability, the acid value of the polyester polymer is preferably 15 mgKOH / g or less, more preferably 10 mgKOH / g or less, and even more preferably 5 mgKOH / g or less. The acid value of the polyester polymer is measured according to JIS K1557-1:2007. In an embodiment, the hydroxyl value of the polyester polymer is preferably 20 mgKOH / g or less, more preferably 10 mgKOH / g or less, and even more preferably 5 mgKOH / g or less, from the viewpoint of compatibility. The hydroxyl value of the polyester polymer is measured according to JIS K1557-1:2007.

[0027] From the viewpoint of achieving both storage stability and compatibility, the acid value and hydroxyl value of the polyester polymer are preferably 15 mgKOH / g or less and 20 mgKOH / g or less, more preferably 10 mgKOH / g or less and 10 mgKOH / g or less, and even more preferably 5 mgKOH / g or less and 5 mgKOH / g or less.

[0028] <Number average molecular weight of polyester polymer> From the viewpoint of improving impact resistance at low temperatures, the number average molecular weight of the polyester polymer is preferably 300 or more, more preferably 350 or more, even more preferably 400 or more, still more preferably 450 or more, and even more preferably 500 or more. From the viewpoint of moldability and compatibility with the 3-hydroxyalkanoic acid polymer, the number average molecular weight is preferably 4,000 or less, more preferably 3,500 or less, and even more preferably 3,000 or less. In one embodiment of the present invention, the number average molecular weight of the polyester polymer is preferably 300 to 4,000, more preferably 400 to 3,500, even more preferably 450 to 3,000, and still more preferably 500 to 2,500. The number average molecular weight of the polyester polymer can be determined by gel permeation chromatography (GPC) measurement in terms of standard polystyrene. When a commercially available product is used, the value listed in the catalog may be used.

[0029] <Content ratio> The resin composition of this embodiment contains preferably 5 to 30 parts by mass, more preferably 6 to 28 parts by mass, even more preferably 7 to 25 parts by mass, and even more preferably 8 to 20 parts by mass of the polyester polymer per 100 parts by mass of the 3-hydroxyalkanoic acid polymer. If the content is within this range, the resin composition can have even better impact resistance at low temperatures.

[0030] The total content of the 3-hydroxyalkanoic acid polymer and polyester polymer in the resin composition of this embodiment is 50% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 98% by mass or more, and may be 100% by mass. The effects of the present invention are more significantly exhibited at this content.

[0031] <Additives> The resin composition of this embodiment may contain additives in addition to the 3-hydroxyalkanoic acid polymer and the polyester polymer. Examples of additives include cellulose nanofibers, natural fibers such as straw, inorganic fillers, softeners, heat aging inhibitors, antioxidants, hydrolysis resistance inhibitors, light stabilizers, antistatic agents, release agents, flame retardants, foaming agents, pigments, dyes, brighteners, ultraviolet absorbers, lubricants, impact resistance improvers, etc. These may be used alone or in combination of two or more. When the above additives are used, the content of the additives in the resin composition may be appropriately determined depending on the desired physical properties of the resin composition.

[0032] <Method of manufacturing resin composition> The method for producing the resin composition of this embodiment is not particularly limited, and it can be produced, for example, by uniformly mixing the 3-hydroxyalkanoic acid polymer, the polyester polymer, and, if necessary, additives. Examples of the mixing method include a method of melt-kneading using a single-screw extruder, a multi-screw extruder, a Banbury mixer, a heated roll, a Brabender, various kneaders, etc., or a method of feeding each component through a separate inlet and melt-kneading the components. Alternatively, pre-blending may be performed before melt-kneading. Examples of pre-blending methods include methods using a mixer such as a Henschel mixer, high-speed mixer, V-blender, ribbon blender, tumbler blender, or conical blender. The upper limit of the temperature during melt-kneading is preferably about 185°C, taking into account the melting points and decomposition temperatures of the 3-hydroxyalkanoic acid polymer and polyester polymer. Therefore, the temperature may be, for example, about 100°C to 185°C, or may be selected arbitrarily from the range of 120°C to 180°C.

[0033] [Molded body] The present invention provides a molded article made of a resin composition. The shape of the molded article may be any molded article that can be produced using the resin composition of this embodiment, and examples of the molded article include molded articles of various shapes such as pellets, films, sheets, plates, pipes, tubes, bottles, fibers, rods, fine particles, particles, foams, etc. The method for producing these molded articles is not particularly limited, and they can be molded by known molding methods such as injection molding, blow molding, press molding, extrusion molding, calendar molding, and molding using a 3D printer.

[0034] [Application] The 3-hydroxyalkanoic acid polymer can be mixed with a polyester polymer to form a resin composition having improved impact resistance at low temperatures. Therefore, the present invention provides a modifier for a 3-hydroxyalkanoic acid polymer, which modifier comprises a polyester polymer. Another preferred embodiment is the use of a polyester polymer as a modifier for a 3-hydroxyalkanoic acid polymer.

[0035] The resin composition of this embodiment can be used for various purposes. The uses of the resin composition are not particularly limited, but include paper, film, sheet, tube, plate, rod, containers such as bottle containers, food trays, bags, parts, and the like. [Example]

[0036] The present invention will be specifically explained below with reference to examples and comparative examples, but the present invention is not limited to these.

[0037] [Measurement and evaluation methods] Various physical properties were measured or evaluated by the following methods.

[0038] <Number average molecular weight of polyester polymer> The polyester polymers (A-1) to (A-6) obtained in the Production Examples were used as samples, and the number average molecular weight (Mn) was determined by gel permeation chromatography (GPC) in terms of standard polystyrene. The specific measurement method is as follows. A tetrahydrofuran (THF) solution was used as the eluent. 10 mg of the sample was weighed out in terms of resin and dissolved in 1 mL of the eluent. The solution was passed through a 0.2 μm membrane filter to prepare a measurement sample. The measurement conditions were as follows: (Measurement conditions) Device: HLC-EcoSEC8320GPC (Tosoh Corporation) Columns: Three columns, KF-803, KF-802.5, and KF-802 (manufactured by Showa Denko KK), were connected in series. Eluent: tetrahydrofuran Flow rate: 0.9mL / min Sample injection volume: 30 μL Column temperature: 40℃ Standard polystyrene: PSt Oligomer Kit (molecular weight 589 to 98,900) manufactured by Tosoh Corporation was used and approximated by a quintic equation. Detector: RI detector

[0039] <Weight-average molecular weight of 3-hydroxyalkanoic acid polymer> The weight average molecular weight (Mw) of the 3-hydroxyalkanoic acid polymer was determined by gel permeation chromatography (GPC) in terms of standard polystyrene. The specific measurement method is as follows. (Measurement conditions) Equipment: High-performance liquid chromatograph LC-20A (Shimadzu Corporation) Columns: KG 4A (1 column) and K-806M (2 columns) (manufactured by Showa Denko KK) were connected in series. Eluent: chloroform Flow rate: 1.0mL / min Sample injection volume: 100 μL Column temperature: 40℃ Standard polystyrene: Polystyrene standards (molecular weight: 2,880 to 6,570,000) manufactured by Agilent Technologies were used and approximated using a quintic equation. Detector: RI detector

[0040] <Hydroxyl value and acid value of polyester polymer> The hydroxyl value and acid value were measured by indicator titration according to Method A of JIS K 1557-1:2007.

[0041] <Impact resistance test> (1) Preparation of test specimens for impact resistance tests The resin compositions obtained in the examples and comparative examples were each subjected to a reduced pressure heat press ("IMC-183B" manufactured by Imoto Machinery Co., Ltd.) using an oil rotary pump to reduce the pressure to -0.1 MPaG, preheated at 165°C for 5 minutes, and pressed at 8 MPa for 3 minutes. They were then pressed at 8 MPa for 3 minutes using a cooling press equipped with water flow cooling to produce a 1.0 mm thick pressed plate. A 50 x 50 mm square piece was cut out from the resulting pressed plate to serve as a test specimen. (2) Impact resistance test The test pieces were conditioned by storing them for 10 hours or more in a low-temperature thermostatic chamber ("HIFLEX FL714C" manufactured by ETAC) adjusted to each test temperature (23°C, 0°C, -15°C) shown in Table 2. After conditioning, the test pieces were subjected to measurements using a DuPont impact resistance tester (manufactured by Taiyu Kizai Co., Ltd.) according to the following steps (a) to (d) to evaluate their impact resistance. (i) Using a support rod, set a 1 kg weight 0.5 m from the support base. (b) The test piece is removed from the thermostatic chamber and placed in an environment of 23°C and 49% humidity, and the test piece is placed between the support and the hammer. (c) The pressure rod is pulled out and the weight is dropped towards the hammer. The time from removing the test piece in (b) to dropping the weight in (c) must be 5 seconds or less. (d) After the weight is dropped, check whether the test piece breaks or not. The above operations (i) to (iv) were carried out on 20 test pieces, and the results were evaluated according to the following criteria. G: The number of test pieces that did not break was 10 or more. NG: The number of test pieces that did not break was less than 10.

[0042] [Each material] The materials used in the examples and comparative examples are as follows:

[0043] (3-hydroxyalkanoic acid polymer) [Manufacturing example I] Alcaligenes eutrophus AC32 (accession number FERM BP-6038), into which polyhydroxyalkanoate synthase genes derived from Aeromonas caviae had been introduced, was cultured according to the method described in Example 1 of Japanese Patent Application Laid-Open No. 2001-340078 to produce a 3-hydroxyalkanoic acid polymer. Specifically, Alcaligenes eutrophus AC32 (accession number FERM BP-6038) (hereinafter abbreviated as "AC32") was cultured as follows. The medium consisted of 1 w / v% meat extract, 1 w / v% Bacto-Trypton, 0.2 w / v% yeast extract, 0.9 w / v% Na2HPO4·12H2O, and 0.15 w / v% KH2PO4 (pH 6.7). The polyester production medium consisted of 1.1 w / v% Na2HPO4·12H2O, 0.19 w / v% KH2PO4, 0.6 w / v% (NH4)2SO4, 0.1 w / v% MgSO4·7H2O, 0.5 v / v% trace metal salt solution (1.6 w / v% FeCl3·6H2O, 1 w / v% CaCl2·2H2O, 0.02 w / v% CoCl2·6H2O, 0.016 w / v% CuSO4·5H2O, 0.012 w / v% NiCl3·6H2O, and 0.01 w / v% CrCl3·6H2O dissolved in 0.1 N hydrochloric acid), 2 w / v% Proex AP-12 (Banshu Seasoning Co., Ltd.), 5 × 10 -6The culture medium was oil-only, with palm oil, palm kernel oil, or coconut oil (4 w / v%) added in three separate portions. A glycerol stock of AC32 strain was inoculated into the preculture medium and cultured for 20 hours. The culture was then inoculated into a 10-L jar fermenter (MD-500, Marubishi Bioengineering Co., Ltd.) containing 6 L of production medium at a concentration of 1.5 v / v%. The operating conditions were a culture temperature of 30°C, an agitation speed of 400 rpm, and an aeration rate of 1.8 L / min. The pH was controlled between 6.6 and 6.8. 5N sulfuric acid and sodium hydroxide were used to control the pH. Culture was continued for up to 72 hours. The cells were collected by centrifugation, washed with methanol, and then freeze-dried. The 3-hydroxyalkanoic acid polymer was extracted from the dried cells using chloroform, and then the chloroform solution containing the 3-hydroxyalkanoic acid polymer was filtered to remove the bacterial components. Methanol was added to the filtrate to precipitate the 3-hydroxyalkanoic acid polymer. The supernatant was then removed by centrifugation, and the resulting precipitate was dried to obtain the 3-hydroxyalkanoic acid polymer. The obtained 3-hydroxyalkanoic acid polymer (hereinafter sometimes referred to as "P3HB3HH-1") was represented by the above-mentioned general formula (I), had a weight-average molecular weight of 590,000, and a ratio of k to p (k / p) of 83.8 / 16.2.

[0044] (Polyester polymer (A)) [Manufacturing example A-1] A flask equipped with a vacuum pump and an apparatus for distilling off the generated liquid was charged with 3-methyl-1,5-pentanediol and adipic acid in a molar ratio of 3-methyl-1,5-pentanediol / adipic acid = 1.6 / 1, and the mixture was heated under a nitrogen atmosphere at normal pressure at 160°C for 3 hours and then at 220°C for 3 hours, while distilling off water. Next, 150 μL of tetraisopropyl titanate was added, and the mixture was reacted for 3 hours at a reduced pressure of 2,000 Pa, and then further reacted for 3 hours at a reduced pressure of 80 Pa, yielding a polyester polyol with the desired molecular weight. Next, 200.0 g of the obtained polyester polyol and 94.3 g of toluene were added to a 1000 mL four-neck glass flask, and 196.1 g (1.9 mol) of acetic anhydride was added to the solution. Next, 9.7 g (80 mmol) of 4-dimethylaminopyridine dissolved in 97.7 g of toluene was added, and the mixture was stirred at 40°C for 60 minutes to obtain a reaction solution with acetylated terminals. The resulting reaction solution was extracted with toluene and water and purified by distillation to obtain 210.0 g of a polyester polymer (A-1).

[0045] <Ratio of each component of polyester polymer (molar ratio)> In the production examples, the ratio of each component of the obtained polyester polymer is as follows: 1 The molar ratio was determined from the spectrum obtained by H-NMR measurement, based on the area ratio of the signal at 4.05-4.18 ppm derived from 3-methyl-1,5-pentanediol, the signal at 4.00-4.05 ppm derived from trimethylolpropane, and the signal at 2.02-2.08 ppm derived from adipic acid and / or sebacic acid. (Measurement conditions) Device: 400YH (manufactured by JEOL Ltd.) Solvent: deuterated chloroform (CDCl3) Measurement temperature: 23℃ Accumulation count: 32 times

[0046] [Manufacturing example A-2] A polyester polymer (A-2) was obtained in the same manner as in Production Example A-1, except that the molar ratio of 3-methyl-1,5-pentanediol to adipic acid was changed to 3-methyl-1,5-pentanediol / adipic acid=1.26 / 1.

[0047] [Manufacturing example A-3] A polyester polymer (A-3) was obtained in the same manner as in Production Example A-1, except that 3-methyl-1,5-pentanediol was changed to a mixture of 3-methyl-1,5-pentanediol / trimethylolpropane in a molar ratio of 2 / 1.

[0048] [Manufacturing example A-4] A polyester polymer (A-4) was obtained in the same manner as in Production Example A-2, except that 3-methyl-1,5-pentanediol was changed to a mixture of 3-methyl-1,5-pentanediol / trimethylolpropane in a molar ratio of 4 / 1.

[0049] [Manufacturing example A-5] A polyester polymer (A-5) was obtained in the same manner as in Production Example A-1, except that sebacic acid was used instead of adipic acid.

[0050] [Manufacturing example A-6] A polyester polymer (A-6) was obtained in the same manner as in Production Example A-1, except that the molar ratio of raw materials charged was changed to 3-methyl-1,5-pentanediol / adipic acid / 2-ethylhexanol = 0.61 / 1 / 0.78 and the terminal modification step was not performed.

[0051] [Table 1]

[0052] [Examples 1 to 12] The polyester polymers (A-1) to (A-6) obtained in Production Examples A-1 to A-6 and the 3-hydroxyalkanoic acid polymer (P3HB3HH-1) obtained in Production Example I were each charged into a twin-screw kneader (manufactured by Technovel Co., Ltd., product name "ULTnano50") in the formulations shown in Table 2, extruded into strands at a cylinder temperature of 170°C, a screw rotation speed of 50 rpm, and a residence time of 1 minute. The resulting strands were then cut into pellets to obtain resin compositions. The resulting resin compositions were evaluated as described above. The results are shown in Table 2.

[0053] [Comparative Example 1] A resin composition was obtained in the same manner as in Example 1, except that the polyester polymer (A-1) was not used. The obtained resin composition was evaluated as described above. The results are shown in Table 2.

[0054] [Table 2]

[0055] Comparison of Examples 1 to 12 with Comparative Example 1 reveals that the resin compositions obtained in the Examples are excellent in impact resistance, particularly at temperatures below 0°C.

Claims

1. A resin composition comprising a 3-hydroxyalkanoic acid polymer represented by the following formula (I) and a polyester polymer, 【Chemical 1】 (In formula (I), the ratio of k to p (k / p) is 70 / 30 to 99 / 1.) The polyester polymer is It is composed of monomer units consisting only of polyhydric alcohol components and dicarboxylic acid components. At least a portion of the ends of the polyester polymer are blocked with a residue of a monoalcohol and / or a residue of a monocarboxylic acid, The polyhydric alcohol of the polyhydric alcohol component is MPD (3-methyl-1,5-pentanediol) and / or TMP (trimethylolpropane), the dicarboxylic acid of the dicarboxylic acid component is adipic acid or sebacic acid; the monoalcohol is 2-ethylhexanol; The resin composition, wherein the monocarboxylic acid is acetic acid.

2. 2. The resin composition according to claim 1, wherein the polyester polymer is contained in an amount of 5 to 30 parts by mass per 100 parts by mass of the 3-hydroxyalkanoic acid polymer.

3. 3. The resin composition according to claim 1, wherein the 3-hydroxyalkanoic acid polymer has a weight average molecular weight of 50,000 to 3,000,000.

4. 3. The resin composition according to claim 1, wherein a ratio of the molar amount of MPD to the total amount of the molar amounts of MPD and TMP contained in the polyester polymer is 0.20 to 1.00, and a ratio of the molar amount of TMP to the total amount of the molar amounts of MPD and TMP is 0 to 0.

80.

5. The resin composition according to claim 1 or 2, wherein the polyester polymer has a hydroxyl value of 20 mgKOH / g or less and an acid value of 15 mgKOH / g or less.

6. 3. The resin composition according to claim 1, wherein the polyester polymer has a number average molecular weight of 300 to 4,000.

7. The resin composition according to claim 1 or 2, wherein the polyhydric alcohol contained in the polyester polymer is the MPD and the TMP.

8. The resin composition according to claim 1 or 2, wherein the polyhydric alcohol contained in the polyester polymer is the MPD.

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