Resin composition and use for same

Abstract

The present invention addresses the problem of providing a resin composition with which a molded body having excellent impact resistance can be obtained. The problem is solved by a resin composition containing: a P3HA-based resin component (A) containing P3HA-based copolymers (a-1) having a weight-average molecular weight of 450,000 to 1,000,000 and P3HA-based copolymers (a-2) having a weight-average molecular weight greater than that of (a-1) by at least 100,000; and inorganic particles (B).

Description

Resin composition and use thereof

[0001] The present invention relates to a resin composition and its use.

[0002] BACKGROUND ART Conventionally, a technique of adding various modifiers (for example, crosslinked particles) to a thermoplastic resin in order to improve the mechanical strength, such as impact strength, of the thermoplastic resin has been known.

[0003] Known examples of crosslinked resin particles include crosslinked resin particles made of resins such as acrylic resins, acrylic silicone resins, and polystyrene (see, for example, Patent Documents 1 and 2).

[0004] Meanwhile, in recent years, from the viewpoint of consideration for the environment during and after the disposal of resin products, there has been active development of biodegradable resins (hereinafter, sometimes referred to as "biodegradable resins"). For example, Patent Document 1 describes a biodegradable and environmentally friendly thermoplastic resin composition containing poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), a type of biodegradable resin.

[0005] Japanese Patent Publication No. 2004-161802

[0006] However, conventional resin compositions such as those described in Patent Document 1 have room for improvement in terms of impact resistance of molded articles obtained by molding the resin compositions.

[0007] One embodiment of the present invention has been made in consideration of the above-mentioned current situation, and an object of the present invention is to provide a resin composition that can provide a molded article having excellent impact resistance.

[0008] In order to solve the above-mentioned problems, one embodiment of the present invention has the following configuration: A resin composition comprising a poly(3-hydroxyalkanoate)-based resin component (A) and inorganic particles (B), wherein the poly(3-hydroxyalkanoate)-based resin component (A) contains a poly(3-hydroxyalkanoate)-based copolymer (a-1) having a weight-average molecular weight of 450,000 to 1,000,000, and a poly(3-hydroxyalkanoate)-based copolymer (a-2) having a weight-average molecular weight 100,000 or more higher than that of the poly(3-hydroxyalkanoate)-based copolymer (a-1).

[0009] According to one embodiment of the present invention, it is possible to provide a resin composition that can provide a molded article having excellent impact resistance.

[0010] An embodiment of the present invention will be described below, but the present invention is not limited thereto. The present invention is not limited to the respective configurations described below, and various modifications are possible within the scope of the claims. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included in the technical scope of the present invention. Furthermore, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic literature and patent documents described in this specification are incorporated herein by reference. Furthermore, unless otherwise specified in this specification, "A to B" representing a numerical range means "A or more (including A and greater than A) and B or less (including B and less than B)."

[0011] [1. Resin Composition] A resin composition according to one embodiment of the present invention is a resin composition comprising a poly(3-hydroxyalkanoate)-based resin component (A) and inorganic particles (B), wherein the poly(3-hydroxyalkanoate)-based resin component (A) contains a poly(3-hydroxyalkanoate)-based copolymer (a-1) having a weight-average molecular weight of 450,000 to 1,000,000, and a poly(3-hydroxyalkanoate)-based copolymer (a-2) having a weight-average molecular weight 100,000 or more greater than that of the poly(3-hydroxyalkanoate)-based copolymer (a-1).

[0012] In this specification, a "poly(3-hydroxyalkanoate)-based resin" may be referred to as a "P3HA-based resin," a "poly(3-hydroxyalkanoate)-based copolymer" may be referred to as a "P3HA-based copolymer," and a "resin composition according to one embodiment of the present invention" may be referred to as the "present resin composition."

[0013] The present inventors have conducted extensive research into resin compositions containing P3HA-based resins and have discovered that the impact resistance of the resulting molded article can be improved by using a mixture of two P3HA-based resins (copolymers) with different molecular weights as the P3HA-based resin component, thereby completing the present invention. They have also discovered that the elastic modulus of the resulting molded article can be improved by further blending inorganic particles into the resin composition.

[0014] The resin composition is biodegradable because it contains a P3HA-based resin, which is a biodegradable plastic. Therefore, it is expected to be useful as an environmentally friendly resin composition and molded article that can address issues such as plastic waste. More specifically, according to one embodiment of the present invention, a biodegradable resin composition or molded article can be provided, thereby reducing soil and / or marine pollution when discarded. That is, one embodiment of the present invention is expected to contribute to the achievement of Sustainable Development Goals (SDGs), such as Goal 12 "Ensure sustainable consumption and production patterns" and / or Goal 14 "Conserve and sustainably use the oceans and marine resources for sustainable development."

[0015] Each component that may be contained in the resin composition will be described in detail below.

[0016] (P3HA-based resin component (A)) The present resin composition contains a P3HA-based resin component (A). Hereinafter, the "P3HA-based resin component (A)" may be referred to as "component (A)." Component (A) can also be said to be the matrix resin in the present resin composition.

[0017] Component (A) is a composition containing a poly(3-hydroxyalkanoate) copolymer (a-1) having a weight-average molecular weight of 450,000 to 1,000,000, and a poly(3-hydroxyalkanoate) copolymer (a-2) having a weight-average molecular weight 100,000 or more higher than that of the poly(3-hydroxyalkanoate) copolymer (a-1). Hereinafter, the "poly(3-hydroxyalkanoate) copolymer (a-1)" may be referred to as the "copolymer (a-1)," and the "poly(3-hydroxyalkanoate) copolymer (a-2)" may be referred to as the "copolymer (a-2)." Component (A) may be a composition containing at least two P3HA-based resins, copolymer (a-1) and copolymer (a-2), and may be a composition consisting of only the two P3HA-based resins, copolymer (a-1) and copolymer (a-2), or may contain other P3HA-based resins in addition to polymer (a-1) and copolymer (a-2).

[0018] P3HA-based resins have the formula: [-CHR-CH ２ -CO-O-] (wherein R is C ｎ H ２ｎ＋１where n is an integer of 1 or more and 15 or less. ) as an essential repeating unit (hereinafter, "repeating unit" may be simply referred to as "unit"). The P3HA-based resin may be a copolymer consisting of two or more types of 3-hydroxyalkanoate repeating units, or a copolymer consisting of 3-hydroxyalkanoate repeating units and other repeating units. In this specification, "P3HA-based resin" refers to a polymer (copolymer) containing 50 mol % or more of 3-hydroxyalkanoate repeating units out of all monomer repeating units (100 mol %). In other words, copolymer (a-1) and copolymer (a-2) are copolymers containing 50 mol % or more of 3-hydroxyalkanoate repeating units out of all monomer repeating units (100 mol %).

[0019] The copolymer (a-1) and / or copolymer (a-2) preferably contains the 3-hydroxyalkanoate repeating units in an amount of 60 mol % or more, and more preferably 70 mol % or more, of all monomer repeating units (100 mol %).

[0020] The P3HA-based resin as copolymer (a-1) and / or copolymer (a-2) is not particularly limited and may be, for example, a copolymer composed of two or more monomers selected from the group consisting of 3-hydroxybutyrate, 3-hydroxypropionate, 3-hydroxyvalerate, 3-hydroxyhexanoate, 3-hydroxyheptanoate, 3-hydroxyoctanoate, 3-hydroxynanoate, 3-hydroxydecanoate, 3-hydroxydodecanoate, 3-hydroxydodecenoate, 3-hydroxytetradecanoate, 3-hydroxyhexadecanoate, and 3-hydroxyoctadecanoate. Alternatively, the copolymer may contain the above-mentioned monomer as the main monomer and, as a comonomer, a hydroxyalkanoate repeating unit other than the 3-hydroxyalkanoate repeating unit (e.g., 4-hydroxybutyrate, etc.). In this specification, a copolymer containing monomer X as a main monomer and monomer Y as a comonomer may be referred to as "poly(X-co-Y)." Poly(X-co-Y) can also be said to be a copolymer containing X repeat units and Y repeat units.

[0021] More specifically, examples of the P3HA resin as copolymer (a-1) and / or copolymer (a-2) include poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter, also referred to as "P3HB3HH"), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate). Copolymer (a-1) and copolymer (a-2) may be the same type of P3HA-based resin or different types of P3HA-based resins. Two or more types of P3HA-based resins may be used as copolymer (a-1) and / or copolymer (a-2).

[0022] Among P3HA-based resins, copolymer (a-1) and / or copolymer (a-2) can be industrially produced using microorganisms or plant raw materials, and are resins with a lower environmental impact that can contribute to resource circulation (carbon neutrality). Therefore, it is preferable that the copolymer (a-1) and / or copolymer (a-2) is a copolymer containing a 3-hydroxyalkanoate repeating unit in which R is an alkane having one carbon atom in the above formula, i.e., a 3-hydroxybutyrate (3HB) repeating unit, and another hydroxyalkanoate repeating unit.

[0023] When copolymer (a-1) and / or copolymer (a-2) are copolymers containing 3HB repeating units, from the viewpoint of the balance between flexibility and strength, the composition ratio of 3HB repeating units (the content ratio of 3HB repeating units) in all monomer repeating units (100 mol%) is preferably 77 to 99 mol%, more preferably 80 mol% to 97 mol%, even more preferably 85 mol% to 95 mol%, and particularly preferably 87 mol% to 92 mol%. When the composition ratio of 3HB repeating units in copolymer (a-1) and / or copolymer (a-2) is within the above range, it has the advantage of being able to provide molded articles that combine flexibility and strength (rigidity) and also have improved productivity. In particular, when the composition ratio of 3HB repeating units in copolymer (a-2) is 87 mol% to 92 mol%, the impact resistance improvement effect due to the inclusion of copolymer (a-2) tends to be further improved, and sufficient impact resistance can be achieved even when the content of copolymer (a-2) in the resin composition is relatively small. The monomer composition ratio in the copolymer that is the P3HA-based resin can be measured by gas chromatography or the like (see, for example, International Publication No. 2014 / 020838). As the copolymer (a-1) and / or the copolymer (a-2), a copolymer having the same composition ratio of 3HB repeating units may be used, or two or more different copolymers may be used in combination.

[0024] P3HA resins can be produced by microorganisms. Microorganisms that produce P3HA resins are not particularly limited as long as they are capable of producing P3HA resins. For example, the first P3HB-producing bacterium was Bacillus megaterium, discovered in 1925. Other known natural microorganisms include Cupriavidus necator (formerly classified as Alcaligenes eutrophus and Ralstonia eutropha) and Alcaligenes latus. These microorganisms accumulate P3HB intracellularly.

[0025] Furthermore, Aeromonas caviae, a P3HB3HH-producing bacterium, is known as a producer of copolymers of 3HB repeating units and other hydroxyalkanoate repeating units. In particular, Alcaligenes eutrophus AC32 (FERM BP-6038) (T. Fukui, Y. Doi, J. Bacteriol., 179, pp. 4821-4830 (1997)), into which genes encoding P3HA synthases have been introduced, is preferred for increasing P3HB3HH productivity. Microbial cells obtained by culturing such microorganisms under appropriate conditions and allowing P3HA-based resins to accumulate within the cells are used. In addition to the above, genetically modified microorganisms into which various P3HA synthesis-related genes have been introduced may be used in accordance with the desired P3HA-based resin, and the culture conditions, including the type of substrate, may be optimized.

[0026] The weight-average molecular weight of copolymer (a-1) is preferably 450,000 to 1,000,000, more preferably 500,000 to 900,000, and even more preferably 550,000 to 800,000. Having the weight-average molecular weight of copolymer (a-1) within the above range has the advantage of providing a molded article with excellent toughness. The weight-average molecular weight of copolymer (a-2) is not particularly limited as long as it is at least 100,000 greater than the weight-average molecular weight of copolymer (a-1). For example, it is preferably 550,000 to 3,000,000, more preferably 600,000 to 2,000,000, and even more preferably 70,000 to 1,500,000. Mixing copolymer (a-1) with copolymer (a-2) having a relatively high weight-average molecular weight can improve the impact resistance of the resulting molded article. In particular, when the weight average molecular weight of the copolymer (a-2) is within the above range, there is an advantage that a molded article having sufficient processability and excellent impact resistance can be provided.

[0027] In this specification, the weight average molecular weight of the P3HA resin (i.e., copolymer (a-1) and copolymer (a-2)) is a value measured by gel permeation chromatography (GPC), for example, using a Shimadzu Corporation "High Performance Liquid Chromatograph 20A System", using a polystyrene gel (e.g., Showa Denko K.K. "K-G 4A", "K-806M", etc.) as a column, and chloroform as a mobile phase, and is a value measured in polystyrene equivalent. In the above measurement, a calibration curve obtained by measuring polystyrene of known molecular weight by GPC can be used, and in this case, the calibration curve can be created using polystyrene of weight average molecular weights of 31,400, 197,000, 668,000, and 1,920,000. In addition, as the column in GPC when creating the calibration curve, a column appropriate for measuring the molecular weight of polystyrene may be used.

[0028] The content of copolymer (a-1) in component (A) is not particularly limited, but is preferably 60 to 99 parts by weight, more preferably 70 to 97 parts by weight, and even more preferably 80 to 95 parts by weight, per 100 parts by weight of component (A). In particular, by setting the content of copolymer (a-1) to 60 to 99 parts by weight, preferably 80 to 95 parts by weight, per 100 parts by weight of component (A), the elastic modulus of the resulting molded article can be further improved, and a resin composition with a relatively low melt viscosity and excellent moldability can be provided. The content of copolymer (a-1) in component (A) may be 1 to 40 parts by weight, 3 to 30 parts by weight, or 5 to 20 parts by weight. The content of copolymer (a-2) in component (A) is not particularly limited, but may be 1 to 99 parts by weight, 20 to 99 parts by weight, or 40 to 99 parts by weight, preferably 60 to 99 parts by weight, more preferably 70 to 97 parts by weight, and even more preferably 80 to 95 parts by weight. In particular, by adjusting the content of copolymer (a-2) to 70 to 97 parts by weight per 100 parts by weight of component (A), the impact resistance of the resulting molded article can be further improved. The content of copolymer (a-2) in component (A) may be 1 to 40 parts by weight, 3 to 30 parts by weight, or 5 to 20 parts by weight.

[0029] As described above, from the viewpoint of further improving the elastic modulus of the obtained molded article and from the viewpoint of providing a resin composition having a relatively low melt viscosity and excellent moldability, it is preferable to increase the content ratio of copolymer (a-1) in component (A), while from the viewpoint of further improving the impact resistance of the obtained molded article, it is preferable to increase the content ratio of copolymer (a-2) in component (A). Therefore, in the present resin composition, it is preferable to appropriately adjust the content ratios of copolymer (a-1) and copolymer (a-2) in the resin composition according to the physical properties desired for the obtained molded article.

[0030] When the content of copolymer (a-1) in 100 parts by weight of component (A) is 60 to 99 parts by weight, that is, when the content ratio of copolymer (a-2) in component (A) is relatively low, from the viewpoint of further improving the impact resistance of the obtained molded article, it is preferable that the resin composition uses as copolymer (a-2) a copolymer that contains 3-hydroxybutyrate (3HB) repeating units and other hydroxyalkanoate repeating units, which has a greater effect of improving impact resistance, and in which the composition ratio of 3HB repeating units is 87 mol % to 92 mol %. That is, a resin composition according to a preferred embodiment of the present invention has the following configuration: a resin composition containing a poly(3-hydroxyalkanoate)-based resin component (A) and inorganic particles (B), wherein the poly(3-hydroxyalkanoate)-based resin component (A) is a poly(3-hydroxyalkanoate)-based copolymer (a-1) having a weight-average molecular weight of 450,000 to 1,000,000, and a poly(3-hydroxyalkanoate)-based copolymer (a-2) having a weight-average molecular weight 100,000 or more higher than that of the poly(3-hydroxyalkanoate)-based copolymer (a-1). A resin composition comprising a (3-hydroxyalkanoate) copolymer (a-2), wherein the content of the poly(3-hydroxyalkanoate) copolymer (a-1) is 60 to 99 parts by weight per 100 parts by weight of the poly(3-hydroxyalkanoate) resin component (A), the poly(3-hydroxyalkanoate) copolymer (a-2) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the composition ratio of the 3-hydroxybutyrate units is 87 to 92 mol %. This configuration makes it possible to provide a molded article having excellent impact resistance and a high elastic modulus, and also to provide a resin composition having a relatively low melt viscosity and excellent moldability.

[0031] The gel fraction of component (A) in the resin composition is not particularly limited, but is preferably less than 50% because this improves moldability, more preferably 40% or less, and even more preferably 30% or less. It may be 20% or less, 10% or less, or even 0%. The gel fraction of component (A) is affected by the amount of crosslinked structures contained in component (A) (in other words, in each P3HA-based resin contained in component (A)). Specifically, the lower the gel fraction of component (A), the smaller the amount of crosslinked structures contained in the P3HA-based resin contained in component (A). In other words, component (A) in the resin composition preferably contains a P3HA-based resin that has a small amount of crosslinked structures or does not have a crosslinked structure. The gel fraction of a P3HA-based resin that is not crosslinked during the production process is usually 0%.

[0032] From the above viewpoints, the gel fractions of both copolymer (a-1) and copolymer (a-2) are preferably less than 50%, more preferably 40% or less, and even more preferably 30% or less, and may be 20% or less, 10% or less, or even 0%. By controlling the gel fractions of the P3HA-based resins contained in component (A) (particularly copolymer (a-1) and copolymer (a-2)) within the above ranges, the gel fraction of component (A) can also be controlled within the same range.

[0033] In this specification, the gel fraction of the P3HA-based resin (composition), including copolymer (a-1) and copolymer (a-2), is a value measured by the following method: A dried P3HA-based resin (composition) to be measured is added to chloroform to a concentration of 0.7 wt % and dissolved at 60 ° C for 30 minutes to obtain a chloroform solution. After allowing to stand at room temperature for 3 hours, the chloroform solution is filtered through a membrane filter with a pore size of 0.45 μm. During filtration, chloroform is poured over the inside of the container and the filter multiple times to thoroughly wash while filtering, thereby preventing loss. The gel remaining on the filter is dried, and the weight together with the filter is measured, and the gel fraction is calculated using the following formula. Formula: Gel fraction = (weight of filter including dried gel - weight of filter only) / weight of P3HA resin (composition) used for measurement × 100 (%) Component (A) may contain a P3HA resin other than copolymer (a-1) and copolymer (a-2) (another P3HA resin). Examples of such other P3HA resins include various P3HA resins having a weight-average molecular weight of less than 450,000.

[0034] The content of the other P3HA-based resin in component (A) is not particularly limited as long as it does not impair the effects of the present invention, but is preferably 0.1 to 10 parts by weight, and more preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total amount of component (A).

[0035] (Inorganic particles (B)) The present resin composition contains inorganic particles (B). Hereinafter, the "inorganic particles (B)" may be referred to as "component (B)." When the present resin composition contains component (B), the elastic modulus of the obtained molded article can be improved.

[0036] The inorganic particles as component (B) are not particularly limited, and known inorganic particles can be used. Among them, component (B) is preferably one or more selected from the group consisting of talc, mica, kaolinite, montmorillonite, and smectite, because they have the advantage of being able to provide a molded product that has sufficient surface smoothness and excellent strength.

[0037] The average particle size of the inorganic particles as component (B) is not particularly limited, but is preferably 1 to 50 μm, more preferably 3 to 40 μm, and even more preferably 5 to 30 μm, because this has the advantage of being able to provide a molded product with superior strength while maintaining sufficient surface smoothness. The average particle size of the inorganic particles can be measured as the median diameter (D50) using a laser diffraction / scattering device such as the "Microtrac MT3100II" manufactured by Nikkiso Co., Ltd.

[0038] (Other Resins) The present resin composition may contain resin components (other resins) other than component (A). The other resins may be any known thermoplastic resins, i.e., resins that can be molded into a desired shape by melting them under heat and then solidifying them by cooling. Examples of such resins include polyolefin resins such as polyethylene and polypropylene, acrylic resins such as polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, and polymethyl methacrylate, AS resin, polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyester resins, and cyclic polyolefins. These other resins may be used alone or in combination of two or more. The other resins may also serve as the matrix resin in the present resin composition.

[0039] Among the other resins, polyester resins are preferred, and from the viewpoint of biodegradability, aliphatic polyesters and aliphatic aromatic polyesters other than P3HA resins are preferred.

[0040] Examples of other resins that are aliphatic polyesters other than P3HA-based resins include PHA-based resins such as polyglycolic acid, polycaprolactone, polylactic acid, and poly(4-hydroxyalkanoate)-based resins, as well as aliphatic polyesters other than PHA, such as polyethylene succinate, polybutylene succinate (hereinafter sometimes referred to as "PBS"), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene succinate adipate (hereinafter sometimes referred to as "PBSA"), polyethylene sebacate, and polybutylene sebacate.

[0041] Examples of other aliphatic aromatic polyester resins include poly(butylene adipate-co-butylene terephthalate) (PBAT), poly(butylene sebacate-co-butylene terephthalate), poly(butylene azelate-co-butylene terephthalate), and poly(butylene succinate-co-butylene terephthalate) (PBST).

[0042] The content of the other resin in the resin composition is not particularly limited as long as it does not impair the effects of the present invention, but it is preferably 1 to 50 parts by weight, more preferably 3 to 30 parts by weight, and even more preferably 5 to 10 parts by weight, per 100 parts by weight of component (A).

[0043] (Other Components) In addition to component (A) and component (B), and other resins that are optional components, the present resin composition may further contain other components such as a crystal nucleating agent, a lubricant, a plasticizer; an organic filler; an antioxidant; a hydrolysis inhibitor; an ultraviolet absorber; a colorant such as a dye or a pigment; and an antistatic agent, within the range that does not impair the functionality of the resulting molded article.

[0044] The resin composition may further contain a crystal nucleating agent. The crystal nucleating agent is not particularly limited, but examples thereof include sugar alcohol compounds derived from natural products such as erythritol, pentaerythritol, galactitol, mannitol, and arabitol; polysaccharides such as chitin and chitosan; polyols such as aliphatic alcohols (polyols), polyvinyl alcohol, and polyethylene oxide; sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, and myristate. metal salts of organic carboxylic acids such as calcium octacosanoate, sodium octacosanoate, calcium octacosanoate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanate, calcium montanate, sodium toluate, sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, and sodium cyclohexanecarboxylate; organic sulfonates such as sodium p-toluenesulfonate and sodium sulfoisophthalate;Carboxylic acid amides such as ethylene stearic acid amide, ethylene bislauric acid amide, palmitic acid amide, hydroxystearic acid amide, erucic acid amide, and trimesic acid tris(t-butylamide), lauric acid esters, palmitic acid esters, oleic acid esters, stearic acid esters, erucic acid esters, N-oleyl palmitic acid ester, N-oleyl oleic acid ester, N-oleyl stearate, N-stearyl oleic acid ester, N-stearyl stearate, N-stearyl erucic acid ester, methylene bisstearate, ethylene bislauric acid ester, ethylene biscapric acid ester, ethylene bisoleic acid ester, ethylene bisstearate, ethylene biserucic acid ester, ethylene Examples of suitable crystal nucleating agents include carboxylic acid esters such as butylene bisisostearate, butylene bisstearate, and p-xylylene bisstearate; dicarboxylic acid derivatives such as dimethyl adipate, dibutyl adipate, diisodecyl adipate, and dibutyl sebacate; cyclic compounds having a functional group C═O and one or more functional groups selected from the group consisting of NH, S, and O in the molecule, such as indigo, quinacridone, and quinacridone magenta; sorbitol derivatives such as bisbenzylidene sorbitol and bis(p-methylbenzylidene)sorbitol; compounds containing a nitrogen-containing heteroaromatic nucleus, such as pyridine, triazine, and imidazole; phosphate ester compounds, bisamides of higher fatty acids, and metal salts of higher fatty acids; branched polylactic acid; and low-molecular-weight poly(3-hydroxybutyrate). These crystal nucleating agents may be used alone or in combination of two or more.

[0045] The resin composition may further contain a lubricant. Examples of the lubricant include, but are not limited to, fatty acid metal salts such as magnesium stearate and calcium stearate; fatty acid amides such as behenic acid amide, stearic acid amide, erucic acid amide, oleic acid amide, methylene bis-stearic acid amide, and ethylene bis-stearic acid amide; polyethylene wax, oxidized polyester wax, glycerin mono-fatty acid esters such as glycerin monostearate, glycerin monobehenate, and glycerin monolaurate; organic acid monoglycerides such as succinic acid saturated fatty acid monoglycerides; sorbitan fatty acid esters such as sorbitan behenate, sorbitan stearate, and sorbitan laurate; polyglycerin fatty acid esters such as diglycerin stearate, diglycerin laurate, tetraglycerin stearate, tetraglycerin laurate, decaglycerin stearate, and decaglycerin laurate; and higher alcohol fatty acid esters such as stearyl stearate. The lubricants may be used alone or in combination of two or more.

[0046] The resin composition may further contain a plasticizer. The plasticizer is not particularly limited, but examples thereof include polyester-based plasticizers such as polypropylene glycol sebacate ester; aliphatic dibasic acid ester-based plasticizers such as di-1-butyl adipate, di-n-butyl sebacate, and di-2-ethylhexyl azelate; glycerin-based plasticizers such as glycerin diacetomonolaurate, glycerin diacetomonocaprylate, and glycerin diacetomonodecanoate; polycarboxylic acid ester-based plasticizers such as tri-2-ethylhexyl acetylcitrate and tributyl acetylcitrate; polyethylene glycol, polypropylene glycol, poly(ethylene oxide-propylene oxide) block and / or random copolymers, and polytetramethylene glycol. polyalkylene glycol-based plasticizers such as those listed above; phosphate ester-based plasticizers such as diphenyl-2-ethylhexyl phosphate and diphenyloctyl phosphate; epoxy-based plasticizers such as epoxidized soybean oil and epoxidized linseed oil fatty acid butyl ester; and castor oil-based plasticizers such as castor oil fatty acid esters, methyl ricinoleate, ethyl ricinoleate, isopropyl ricinoleate, butyl ricinoleate, ethylene glycol monoricylate, propylene glycol monoricylate, trimethylolpropane monoricylate, sorbitan monoricylate, castor oil fatty acid polyethylene glycol esters, castor oil ethylene oxide adducts, castor oil-based polyols, castor oil-based toluene, and castor oil-based diols. These plasticizers may be used alone or in combination of two or more.

[0047] The resin composition may further contain an organic filler. The organic filler is not particularly limited, but examples thereof include fillers composed of naturally occurring materials such as wood-based materials (e.g., wood chips, wood flour, sawdust, etc.), rice husks, rice flour, starch, corn starch, rice straw, wheat straw, and natural rubber; organic fibers such as natural plant fibers, natural animal fibers, and synthetic fibers; and fillers composed of synthetic resin materials such as polyester, polyacrylic, polyamide, nylon, polyethylene, polyolefin, polyvinyl alcohol, polyvinyl chloride, polyurethane, polyacetal, aramid, PBO (poly-p-phenylene benzobisoxazole), polyphenylene sulfide, acetyl cellulose, polybenzazole, polyarylate, polyvinyl acetate, and synthetic rubber.

[0048] The resin composition may further contain natural plant fibers. Examples of natural plant fibers include, but are not limited to, kenaf fiber, abaca fiber, bamboo fiber, jute fiber, hemp fiber, linen fiber, henequen (sisal), ramie fiber, hemp, cotton, banana fiber, coconut fiber, palm, paper mulberry, Mitsumata, and bagasse. Other examples include regenerated fibers such as pulp, cellulose fiber, and rayon processed from plant fibers. Examples of natural animal fibers include wool, silk, cashmere, and mohair.

[0049] The resin composition may further contain an antioxidant. The antioxidant is not particularly limited, but examples thereof include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These antioxidants may be used alone or in combination of two or more.

[0050] The resin composition may further contain a hydrolysis inhibitor. The hydrolysis inhibitor is not particularly limited, but examples thereof include carbodiimide compounds, epoxy compounds, isocyanate compounds, and oxazoline compounds. These hydrolysis inhibitors may be used alone or in combination of two or more.

[0051] The resin composition may further contain an ultraviolet absorber. The ultraviolet absorber is not particularly limited, but examples thereof include benzophenone compounds, benzotriazole compounds, triazine compounds, salicylic acid compounds, cyanoacrylate compounds, and nickel complex salt compounds. These ultraviolet absorbers may be used alone or in combination of two or more.

[0052] The resin composition may further contain a colorant such as a pigment or dye. The colorant, such as a pigment or dye, is not particularly limited, but examples thereof include inorganic colorants such as titanium oxide, calcium carbonate, chromium oxide, cuprous oxide, calcium silicate, iron oxide, carbon black, graphite, titanium yellow, and cobalt blue; soluble azo pigments such as lake red, lithol red, and brilliant carmine; insoluble azo pigments such as dinitrian orange and fast yellow; phthalocyanine pigments such as monochlorophthalocyanine blue, polychlorophthalocyanine blue, and polybromophthalocyanine green; condensed polycyclic pigments such as indigo blue, perylene red, isoindolinone yellow, and quinacridone red; and dyes such as oracet yellow. These colorants may be used alone or in combination of two or more.

[0053] The resin composition may further contain an antistatic agent. The antistatic agent is not particularly limited, but examples thereof include low-molecular-weight antistatic agents such as fatty acid ester compounds, aliphatic ethanolamine compounds, and aliphatic ethanolamide compounds, and polymeric antistatic agents. These antistatic agents may be used alone or in combination of two or more.

[0054] The resin composition may further contain any of the following additives: catalyst deactivators (hindered phenol compounds, thioether compounds, vitamin compounds, triazole compounds, polyamine compounds, hydrazine derivative compounds, phosphorus compounds, etc.), mold release agents (montanic acid and its salts, esters thereof, half esters thereof, stearyl alcohol, stearamide, polyethylene wax, etc.), color inhibitors (phosphites, hypophosphites, etc.), silane coupling agents (epoxy silane coupling agents, amino silane coupling agents, (meth)acrylic silane coupling agents, isocyanate silane coupling agents, etc.), flame retardants (red phosphorus, phosphate esters, brominated polystyrene, brominated polyphenylene ether, brominated polyisocyanate, methyl methyl silane ... The composition may also contain: polycarbonate, aluminum hydroxide, magnesium hydroxide, melamine and cyanuric acid or salts thereof, silicon compounds, etc.), conductive agents (carbon black, etc.), sliding property improvers (graphite, fluororesin, etc.), epoxy compounds (glycidyl ether compounds, glycidyl ester compounds, polymer compounds grafted or copolymerized with a glycidyl compound, etc.), acid anhydride compounds (maleic anhydride, succinic anhydride, polymer compounds grafted or copolymerized with an acid anhydride, etc.), carbodiimide compounds (N,N'-di-2,6-diisopropylphenylcarbodiimide, 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, polycarbodiimide, etc.), etc.

[0055] The content of each of the other components described above is not particularly limited as long as the effect of one embodiment of the present invention is exhibited, and can be appropriately determined by a person skilled in the art.

[0056] [2. Method for producing a resin composition] In one embodiment of the present invention, there is provided a method for producing a resin composition, which includes a mixing step of mixing component (A) and component (B). In this specification, the "method for producing a resin composition according to one embodiment of the present invention" may be referred to as the "method for producing the present resin composition." The "method for producing the present resin composition" can be suitably used as a method for producing the "present resin composition."

[0057] Specific aspects of component (A), component (B), and other components used in the method for producing the resin composition are the same as those described in the above section [3. Resin composition]. Therefore, the description therein is incorporated by reference and will not be repeated in this section.

[0058] <Mixing Step> The method for producing the resin composition includes a mixing step of mixing component (A), component (B), and, if necessary, other components. The amount of each component blended in the mixing step determines the content of each component in the resulting resin composition. Therefore, in the mixing step, each component is mixed so that the content of each component in the resulting resin composition is the desired amount.

[0059] The mixing step is not particularly limited as long as it is a method for mixing component (A) and component (B), and can be carried out by a known method. The mixing step can be carried out, for example, by mixing the thermoplastic resin, crosslinked resin particles, optionally a crystal nucleating agent and / or nucleating agent, and other components using an extruder, kneader, Banbury mixer, kneading roll, or the like. The mixing step may include a melt-kneading step in which the crosslinked resin particles and the thermoplastic resin are melt-kneaded. When melt-kneading, it is preferable to mix while taking care to prevent a decrease in the molecular weight of component (A) due to thermal decomposition. Alternatively, the resin composition can be produced by dissolving each component in a soluble solvent and then removing the solvent.

[0060] When the resin composition is produced by melt-kneading, each component may be charged separately into an extruder or the like, or each component may be mixed in advance and then charged into an extruder or the like.

[0061] When melt-kneaded using an extruder, the resulting resin composition may be extruded into a strand shape and then cut to be processed into particle shapes such as a bar shape, a cylindrical shape, an elliptical cylinder shape, a sphere shape, a cube shape, a rectangular parallelepiped shape, or the like.

[0062] The resin temperature during melt-kneading cannot be generally specified because it depends on the melting point and melt viscosity of the resin used, but from the viewpoint of uniformly dispersing component (B) while avoiding thermal decomposition of component (A), it is preferably 140 to 220°C, more preferably 150 to 210°C, and even more preferably 160 to 200°C.

[0063] [3. Molded Article] In one embodiment of the present invention, a molded article containing the present resin composition is provided. Hereinafter, the "molded article according to one embodiment of the present invention" may be referred to as the "present molded article." The present molded article can also be said to be a molded article obtained by molding the present resin composition. In providing the present molded article, the molding method of the present resin composition is not particularly limited, and commonly used molding methods can be applied. Specific molding methods include inflation film molding, extrusion blow molding, injection blow molding, extrusion molding, calendar molding, vacuum molding, and injection molding. The molded article obtained by molding the present resin composition can also be said to be a molded article containing the present resin composition.

[0064] By carrying out the above-described molding method using the present resin composition, a molded article having excellent tensile impact strength, specifically a sheet, film, blow molded article, extrusion molded article, vacuum molded article, or injection molded article, can be produced with good productivity. In other words, the present molded article can be a sheet, film, blow molded article, extrusion molded article, vacuum molded article, or injection molded article.

[0065] The molded article can be suitably used in agriculture, fisheries, forestry, horticulture, medicine, hygiene products, the food industry, clothing, non-clothing, packaging, automobiles, building materials, and other fields.

[0066] (Impact Resistance) The present molded article is a molded article with excellent impact resistance. In this specification, the impact resistance of the molded article can be evaluated by a drop weight strength test. A specific test method for the drop weight strength test is as follows: A sheet-like molded article with a thickness of 700 μm is cut into a 40 mm square to prepare a measurement sample. The prepared sample is subjected to a drop weight test using a DuPont drop impact tester (shooting tip radius 7.93 mm) with a 300 g drop weight. The drop height is increased in 10 mm increments from 100 mm, and the drop height at which cracks or fractures occur in the sample is recorded.

[0067] The higher the drop height (hereinafter sometimes simply referred to as "drop height") at which cracks or breaks occur in the sample, measured using the above method, the more impact-resistant the molded body being measured is.

[0068] The drop height of the present molded body is preferably 260 mm or more, more preferably 280 mm or more, and even more preferably 300 mm or more. A drop height of 260 mm or more of the molded body means that the molded body has excellent impact resistance. The higher the drop height of the present molded body, the more preferable it is, and the upper limit is not particularly limited, but it can be, for example, 500 mm or less.

[0069] (Elastic Modulus) The present molded article is also excellent in elastic modulus. In this specification, the elastic modulus of the molded article can be evaluated by the tensile modulus. A specific test method for the tensile modulus is as follows: a sheet-like molded article having a thickness of 700 μm is cut into a dumbbell shape conforming to JIS K 7127 TYPE 5 to prepare a measurement sample. A tensile test is performed on this sample using a tensile tester (Shimadzu Corporation: EZ-LX 1kN) in accordance with JIS K 7127 at a tension speed of 100 mm / min. The tensile modulus is calculated based on the S-S curve obtained by the tensile test.

[0070] The higher the tensile modulus calculated by the above method, the more excellent the elastic modulus of the molded article being measured.

[0071] The tensile modulus of the present molded body is preferably 1,500 MPa or more, more preferably 2,000 MPa or more, even more preferably 2,500 MPa or more, and even more preferably 3,000 MPa. A tensile modulus of the molded body of 1,500 MPa or more means that the molded body has an excellent modulus of elasticity. The higher the tensile modulus of the present molded body, the more preferable it is, and the upper limit is not particularly limited, but it can be, for example, 5,5000 MPa or less.

[0072] [4. Others] One aspect of the present invention may include the following configuration.

[0073] [1] A resin composition comprising a poly(3-hydroxyalkanoate)-based resin component (A) and inorganic particles (B), wherein the poly(3-hydroxyalkanoate)-based resin component (A) contains a poly(3-hydroxyalkanoate)-based copolymer (a-1) having a weight-average molecular weight of 450,000 to 1,000,000, and a poly(3-hydroxyalkanoate)-based copolymer (a-2) having a weight-average molecular weight 100,000 or more higher than that of the poly(3-hydroxyalkanoate)-based copolymer (a-1).

[0074] [2] The resin composition according to [1], wherein the poly(3-hydroxyalkanoate) copolymer (a-2) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the composition ratio of the 3-hydroxybutyrate units is 77 to 99 mol%.

[0075] [3] The resin composition according to [1] or [2], wherein the content of the poly(3-hydroxyalkanoate)-based copolymer (a-1) in 100 parts by weight of the poly(3-hydroxyalkanoate)-based resin component (A) is 60 to 99 parts by weight.

[0076] [4] The resin composition according to any one of [1] to [3], wherein the poly(3-hydroxyalkanoate) copolymer (a-1) and / or (a-2) is at least one selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate), and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate).

[0077] [5] The resin composition according to any one of [1] to [4], wherein the poly(3-hydroxyalkanoate) copolymer (a-1) and / or (a-2) is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).

[0078] [6] The resin composition according to any one of [1] to [5], wherein the poly(3-hydroxyalkanoate) copolymer (a-1) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the composition ratio of the 3-hydroxybutyrate units is 77 to 99 mol%.

[0079] [7] The resin composition according to any one of [1] to [6], wherein the inorganic particles (B) are one or more selected from the group consisting of talc, mica, kaolinite, montmorillonite, and smectite.

[0080] [8] A molded article comprising the resin composition according to any one of [1] to [7].

[0081] [9] The molded article according to [8], which is a sheet, a film, a blow molded article, an extrusion molded article, a vacuum molded article, or an injection molded article.

[0082]

[10] The resin composition according to [2], wherein the composition ratio of the 3-hydroxybutyrate unit is 87 to 92 mol%.

[0083] The present invention will be specifically explained below with reference to examples, but the technical scope of the present invention is not limited to these examples.

[0084] [Materials] The materials used in the examples and comparative examples are shown below.

[0085] (Component (A)) (A-1): Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), obtained in accordance with the method described in WO 2008 / 010296, having a composition ratio of 3-hydroxyhexanoate (3HB) units of 94.2 mol% and a weight-average molecular weight of 530,000. (A-2): Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH), obtained in accordance with the method described in WO 2008 / 010296, having a composition ratio of 3-hydroxyhexanoate (3HB) units of 94.2 mol% and a weight-average molecular weight of 760,000. (A-3): Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) having a composition ratio of 3HB units of 89.5 mol% and a weight-average molecular weight of 540,000, produced in accordance with the method described in WO 2013 / 147139. (A-4): Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) having a composition ratio of 3HB units of 89.5 mol% and a weight-average molecular weight of 780,000, produced in accordance with the method described in WO 2013 / 147139. (A-5): Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (P3HB3HH) having a composition ratio of 3HB units of 89.5 mol% and a weight average molecular weight of 1,300,000, produced in accordance with the method described in WO 2013 / 147139. The gel fraction of each of the P3HAs (A-1) to (A-5) was 0%.

[0086] <Measurement of Monomer Composition Ratio of Copolymer> The monomer composition ratio of each copolymer serving as component (A) was determined as follows. 1 mL of a concentrated sulfuric acid (98%)-methanol mixture (15:85) and 1 mL of chloroform were added to 20 mg of the target copolymer, the mixture was sealed, and heated at 100°C for 140 minutes to obtain methyl esters, which were decomposition products of the copolymer. After cooling, 0.5 mL of deionized water was added to the mixture, and the mixture was mixed thoroughly and allowed to stand until the aqueous and organic layers separated. The monomer unit composition of the copolymer decomposition product in the separated organic layer was then analyzed by capillary gas chromatography. The monomer composition ratio of the target copolymer was calculated from the obtained peak area.

[0087] <Measurement of Weight Average Molecular Weight> The weight average molecular weight of each copolymer (component (A)) was determined by first dissolving the copolymer to be measured in chloroform, heating it in a hot water bath at 60°C for 0.5 hours, and filtering the soluble matter through a disposable PTFE filter with a 0.45 µm pore size. After filtration, the filtrate was subjected to GPC measurement under the following conditions to determine the polystyrene-equivalent weight average molecular weight of the copolymer. GPC measurement device: High performance liquid chromatograph 20A system manufactured by Shimadzu Corporation Column: K-G 4A (1 column), K-806M (2 columns) manufactured by Showa Denko K.K. Sample concentration: 1 mg / ml Free liquid: Chloroform solution Free liquid flow rate: 1.0 ml / min Sample injection amount: 100 μL Analysis time: 30 minutes Standard sample: Standard polystyrene (Inorganic particles (B)) (B-1): Mica (manufactured by Yamaguchi Mica Co., Ltd.: A-21S, average particle size 22 μm) (B-2): Talc (manufactured by Nippon Talc Co., Ltd.: Micro Ace K-1, average particle size 8 μm).

[0088] [Evaluation Methods] The methods for evaluating the various physical properties used in the Examples and Comparative Examples are described below.

[0089] <Tensile Modulus> Measurement samples were prepared by cutting the sheet-like molded articles prepared in the Examples and Comparative Examples into dumbbell shapes conforming to JIS K 7127 TYPE 5. A tensile test was performed on these samples using a tensile tester (Shimadzu Corporation: EZ-LX 1kN) at a tension speed of 100 mm / min conforming to JIS K 7127. The tensile modulus was calculated based on the S-S curve obtained from the tensile test.

[0090] <Drop Weight Strength> The sheet-like molded articles prepared in the Examples and Comparative Examples were cut into 40 mm squares to serve as measurement samples. The prepared samples were subjected to a drop weight test using a DuPont drop impact tester (7.93 mm tip radius) with a 300 g drop weight. The drop height was increased in 10 mm increments from 100 mm, and the drop height at which cracks or fractures occurred in the sample was recorded.

[0091] Example 1: 90 parts by weight of (A-1) and 10 parts by weight of (A-4) were mixed as component (A), and 30 parts by weight of (B-1) was mixed as component (B), and the mixture was melt-kneaded for 3 minutes at 16 rpm using a two-roll mill set at 145°C to obtain a resin composition containing the above components. This resin composition was placed in a calendar roll at 130-140°C, and the thickness was adjusted while rolling to obtain a sheet-like molded product with a thickness of 700 μm. The tensile modulus and drop weight strength of the obtained molded product were evaluated, and the results are shown in Table 1. In Example 1, (A-1) corresponds to copolymer (a-1), and (A-4) corresponds to copolymer (a-2).

[0092] Examples 2 to 4, Comparative Examples 1 and 2 Resin compositions and sheet-like molded articles were prepared in the same manner as in Example 1, except that the compounding ratios of the components were changed as shown in Table 1. The tensile modulus and drop weight strength of the obtained molded articles were evaluated in the same manner as in Example 1, and the results are shown in Table 1. In Examples 2 and 3, (A-1) corresponds to the copolymer (a-1), and (A-5) corresponds to the copolymer (a-2). In Example 4, (A-3) corresponds to the copolymer (a-1), and (A-2) corresponds to the copolymer (a-2).

[0093] A comparison of Examples 1 to 3 with Comparative Example 1 shows that a molded article having excellent impact resistance can be provided by mixing (A-1) with (A-4) or (A-5) having a relatively high molecular weight. Furthermore, in Examples 1 to 3, it can be seen that the elastic modulus of the molded article is also improved by increasing the content ratio of copolymer (a-1). A comparison of Example 4 with Comparative Example 2 shows that a molded article having excellent impact resistance can also be provided by mixing (A-3) with (A-2) having a relatively high molecular weight. Furthermore, in Example 4, it can be seen that the impact resistance of the molded article is further improved by increasing the content ratio of copolymer (a-2).

[0094] According to one embodiment of the present invention, a novel resin composition capable of providing a molded article having excellent impact resistance can be provided, and therefore, this embodiment of the present invention can be suitably used in fields such as agriculture, fisheries, forestry, horticulture, medicine, hygiene products, the food industry, clothing, non-clothing, packaging, automobiles, building materials, and the like.

Claims

1. A resin composition comprising a poly(3-hydroxyalkanoate)-based resin component (A) and inorganic particles (B), wherein the poly(3-hydroxyalkanoate)-based resin component (A) contains a poly(3-hydroxyalkanoate)-based copolymer (a-1) having a weight average molecular weight of 450,000 to 1,000,000, and a poly(3-hydroxyalkanoate)-based copolymer (a-2) having a weight average molecular weight 100,000 or more higher than that of the poly(3-hydroxyalkanoate)-based copolymer (a-1).

2. The resin composition according to claim 1, wherein the poly(3-hydroxyalkanoate) copolymer (a-2) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the composition ratio of the 3-hydroxybutyrate units is 77 to 99 mol %.

3. The resin composition described in claim 1, wherein the content of the poly(3-hydroxyalkanoate)-based copolymer (a-1) in 100 parts by weight of the poly(3-hydroxyalkanoate)-based resin component (A) is 60 to 99 parts by weight.

4. The resin composition according to claim 1, wherein the poly(3-hydroxyalkanoate) copolymer (a-1) and / or (a-2) is at least one selected from the group consisting of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), poly(3-hydroxybutyrate-co-3-hydroxypropionate), poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyoctanoate), poly(3-hydroxybutyrate-co-3-hydroxyoctadecanoate), poly(3-hydroxybutyrate-co-3-hydroxydecanoate) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate-co-3-hydroxyhexanoate).

5. The resin composition according to claim 1, wherein the poly(3-hydroxyalkanoate) copolymer (a-1) and / or (a-2) is poly(3-hydroxybutyrate-co-3-hydroxyhexanoate).

6. The resin composition according to claim 1, wherein the poly(3-hydroxyalkanoate) copolymer (a-1) is a copolymer of 3-hydroxybutyrate units and other hydroxyalkanoate units, and the composition ratio of the 3-hydroxybutyrate units is 77 to 99 mol %.

7. The resin composition according to claim 1, wherein the inorganic particles (B) are one or more types selected from the group consisting of talc, mica, kaolinite, montmorillonite, and smectite.

8. A molded article comprising the resin composition according to any one of claims 1 to 7.

9. The molded article according to claim 8, which is a sheet, a film, a blow molded article, an extrusion molded article, a vacuum molded article, or an injection molded article.

10. The resin composition according to claim 2, wherein the composition ratio of the 3-hydroxybutyrate unit in the poly(3-hydroxyalkanoate) copolymer (a-2) is 87 to 92 mol %.

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