Crosslinked resin particles and modifier for thermoplastic resin

Abstract

The present invention addresses the problem of providing brand new crosslinked resin particles having biodegradability. Provided are crosslinked resin particles containing a biodegradable resin having a glass transition temperature of less than 0 DEG C and having a gel fraction of 50% or more.

Description

Technical Field

[0001] This invention relates to crosslinked resin particles and modifiers for thermoplastic resins. Background Technology

[0002] Previously, in order to improve the mechanical strength of thermoplastic resins, such as impact resistance, a technique was known to be the addition of various modifiers (e.g., crosslinking particles) to thermoplastic resins.

[0003] Crosslinked resin particles are known, for example, to be composed of resins such as acrylic resins, silicone acrylic resins, and polystyrene (e.g., Patent Documents 1 and 2).

[0004] On the other hand, in recent years, from the perspective of environmental protection during and after the disposal of resin products, the development of biodegradable resins (hereinafter sometimes referred to as "biodegradable resins") has been actively underway. For example, Patent Document 3 describes a technique for crosslinking a biodegradable resin by melt-blending a poly(3-hydroxyalkanoate) as a biodegradable resin in the presence of an organic peroxide. However, although it describes that the crosslinked resin obtained by such melt-blending is used to form films and / or sheets, it does not describe at all how to manufacture crosslinked resin particles with small particle sizes.

[0005] [Existing technical documents]

[0006] (Patent Documents)

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-56770

[0008] Patent Document 2: Japanese Patent Application Publication No. 2003-82191

[0009] Patent Document 3: International Publication No. 2019 / 022008 Summary of the Invention

[0010] (The problem the invention aims to solve)

[0011] To date, no biodegradable cross-linked resin particles have been observed.

[0012] One embodiment of the present invention was made in view of the above-mentioned situation, with the aim of providing a novel cross-linked resin particle with biodegradability.

[0013] (Technical means used to solve the problem)

[0014] The inventors conducted in-depth research to solve the above-mentioned problems, and as a result, successfully used various biodegradable resins to manufacture novel cross-linked resin particles, thereby completing one embodiment of the present invention.

[0015] The crosslinked resin particles of one embodiment of the present invention comprise a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more.

[0016] The thermoplastic resin modifier of one embodiment of the present invention comprises cross-linked resin particles, said cross-linked resin particles comprising a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more.

[0017] (Invention Effects)

[0018] According to one embodiment of the present invention, it is possible to provide a novel cross-linked resin particle with biodegradability. Detailed Implementation

[0019] The following describes one embodiment of the present invention, but the present invention is not limited thereto. The present invention is not limited to the embodiments described below, and various modifications can be made within the scope of the technical concept shown throughout the specification. Furthermore, embodiments or examples obtained by combining the technical means disclosed in different embodiments or examples are also included within the technical scope of the present invention. Moreover, new technical features can be formed by combining the technical means disclosed in each embodiment. All academic and patent documents described in this specification are cited as references in this specification. In addition, unless otherwise specified, the expression "A~B" in this specification means "A and above (including A and greater than A), B and below (including B and less than B)".

[0020] [1. Cross-linked resin particles]

[0021] The crosslinked resin particles of one embodiment of the present invention comprise a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more.

[0022] In this specification, "glass transition temperature" is sometimes referred to as "Tg", and "crosslinked resin particles of one embodiment of the present invention" is sometimes referred to as "the crosslinked resin particles of this invention".

[0023] This cross-linked resin granule contains a biodegradable resin (A), thus possessing the advantage of biodegradability. Therefore, it is expected to be useful in addressing the plastic waste problem, thus having practical value as an environmentally friendly cross-linked resin granule. Furthermore, because this cross-linked resin granule is biodegradable, resin compositions and molded articles containing this cross-linked resin granule can help suppress soil pollution caused by waste. This can, for example, contribute to achieving Sustainable Development Goals (SDGs) such as Goal 12, "Ensuring sustainable consumption and production patterns." Moreover, since the biodegradable resin (A) is not only soil-degradable but also marine-degradable, resin compositions and molded articles containing this cross-linked resin granule can help suppress not only soil pollution caused by waste but also marine pollution.

[0024] In a preferred embodiment of the present invention, the molded article formed from the resin composition comprising the cross-linked resin particles and the thermoplastic resin also has the advantage of excellent elongation at break. In a more preferred embodiment of the present invention, the molded article formed from the resin composition comprising the cross-linked resin particles and the thermoplastic resin also has the advantage of excellent tensile impact strength.

[0025] <Biodegradable Resin (A)>

[0026] There are no particular limitations on biodegradable resins (A) as long as they have a Tg below 0°C and are biodegradable.

[0027] Examples of biodegradable resins (including both biodegradable resins with a Tg below 0°C and biodegradable resins with a Tg above 0°C) include aliphatic polyesters and aliphatic aromatic polyesters.

[0028] The aliphatic polyesters may include, for example: (i) polyhydroxyalkanoate resins (hereinafter sometimes also referred to as "PHA"), (ii) polylactic acid (hereinafter sometimes also referred to as "PLA"), (iii) polycaprolactone (hereinafter sometimes also referred to as "PCL"), and (iv) aliphatic polyesters other than PHA, PLA and PCL.

[0029] "PHA" is a general term for polymers containing hydroxyalkanoic acid as monomer units (monomer repeating units), and they are generally biodegradable. PHA is an aliphatic polyester, preferably a polyester without aromatic rings. In this specification, "PHA" refers to a polymer in which the content of hydroxyalkanoic acid repeating units accounts for more than 50 mol% of all monomer repeating units (100 mol%). PHA preferably contains more than 60 mol% and more preferably more than 70 mol% of hydroxyalkanoic acid repeating units in total monomer repeating units (100 mol%).

[0030] There are no particular limitations on PHA. Examples of PHAs include polyglycolic acid, poly(3-hydroxyalkanoate) resins (hereinafter sometimes referred to as "P3HA"), and poly(4-hydroxyalkanoate) resins. A single type of PHA may be used alone, or two or more types may be used in combination. PHA preferably contains a poly(3-hydroxyalkanoate) resin, and more preferably a poly(3-hydroxyalkanoate) resin (in other words, it is composed only of a poly(3-hydroxyalkanoate) resin).

[0031] "Polyglycolic acid" refers to a resin containing repeating units represented by [-CH2-CO-O-] accounting for more than 50 mol% of all monomer repeating units (100 mol%). Polyglycolic acid may contain repeating units represented by [-CH2-CO-O-] accounting for more than 60 mol%, more than 70 mol%, more than 80 mol%, or more than 90 mol% of all monomer repeating units (100 mol%).

[0032] Polyglycolic acid can be a homopolymer of glycolic acid or a copolymer of glycolic acid with monomers other than glycolic acid (such as copolymers of glycolic acid and lactic acid, and copolymers of glycolic acid and caprolactone).

[0033] Polyglycolic acid can be obtained by known methods such as the condensation polymerization of glycolic acid and the ring-opening polymerization of glycolide.

[0034] The P3HA contains a repeating 3-hydroxyalkanoic acid unit represented by the formula [-CHR-CH2-CO-O-] (where R is a C-hydroxyalkanoic acid compound). n H 2n+1 The term "P3HA" refers to a polyhydroxyalkanoate in which the alkyl group (n is an integer of 1 to 15) is used as a repeating unit. In this specification, "P3HA" means a resin containing at least 50 mol% of the aforementioned 3-hydroxyalkanoic acid repeating unit in all monomer repeating units (100 mol%). Preferably, the P3HA contains at least 60 mol% and more preferably at least 70 mol% of the aforementioned 3-hydroxyalkanoic acid repeating unit in all monomer repeating units (100 mol%).

[0035] P3HA is not particularly limited and can be a homopolymer containing the aforementioned repeating units or a copolymer containing the aforementioned repeating units. Examples of such copolymers include copolymers formed from one or more monomers selected from 3-hydroxybutyric acid (hereinafter sometimes also referred to as "3HB"), namely 3-hydroxypropionic acid, 3-hydroxyvalerate, 3-hydroxyhexanoic acid, 3-hydroxyheptanoic acid, 3-hydroxyoctanoic acid, 3-hydroxynonanoic acid, 3-hydroxydecanoic acid, 3-hydroxyundecanoic acid, 3-hydroxydodecanoic acid, 3-hydroxytridecanoic acid, 3-hydroxytetradecanoic acid, 3-hydroxyhexadecanoic acid, and 3-hydroxyoctadecanoic acid. Alternatively, as other examples of the above copolymers, one could cite a copolymer formed from 3HB and one or more monomers selected from 4-hydroxybutyric acid, 4-hydroxyvalerate, 4-hydroxyhexanoic acid, 4-hydroxyheptanoic acid, 4-hydroxyoctanoic acid, 4-hydroxynonanoic acid, 4-hydroxydecanoic acid, 4-hydroxyundecanoic acid, 4-hydroxydodecanoic acid, 4-hydroxytridecanoic acid, 4-hydroxytetradecanoic acid, 4-hydroxyhexadecanoic acid, and 4-hydroxyoctadecanoic acid.

[0036] Examples of P3HAs include: poly(3-hydroxybutyrate) (hereinafter sometimes referred to as "P3HB"), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (hereinafter sometimes referred to as "P3HB3HH"), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate) (hereinafter sometimes referred to as "P3HB3HH3HO"), and poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (hereinafter sometimes referred to as "P3HB4HB"), etc. Only one type of P3HA can be used, or two or more types can be used in combination. In this specification, "poly(X-co-Y)" refers to a copolymer containing repeating units X and Y, meaning a copolymer formed by copolymerizing the monomers that will be the source of the repeating units X and the monomers that will be the source of the repeating units Y. In addition, when P3HA is produced by microorganisms, there may be trace amounts (less than 1 mol%) of monomers participating in copolymerization. However, as long as this does not significantly affect the physical properties of the resulting P3HA, it can be considered that the monomer did not participate in copolymerization, and it can be called by a name that does not contain the monomer.

[0037] P3HA can be produced by microorganisms. P3HA produced by these microorganisms is typically composed solely of repeating 3-hydroxyalkanoic acid units in the D-body (R-body). Among microbially produced P3HAs, from the viewpoint of easier industrial production, P3HB, P3HB3HH, P3HB3HH3HO, and P3HB4HB are preferred, with P3HB3HH, P3HB3HH3HO, and P3HB4HB being more preferred.

[0038] P3HA preferably contains 3-hydroxybutyric acid (3HB) repeating units. When P3HA contains 3HB repeating units, from the viewpoint of balancing flexibility and strength, the composition ratio of the 3HB repeating unit in all monomer repeating units (100 mol%) is preferably 60 mol% to 99 mol%, more preferably 61 mol% to 97 mol%, and even more preferably 62 mol% to 95 mol%. When the composition ratio of 3HB repeating units in P3HA is 60 mol% or more, it has the advantage of further improving the rigidity of the cross-linked resin particles. On the other hand, when the composition ratio of 3HB repeating units in P3HA is 99 mol% or less, it has the advantage of further improving the flexibility of the cross-linked resin particles. Here, the monomer composition ratio of P3HA can be determined by gas chromatography or the like (for example, refer to International Publication No. 2014 / 020838). As P3HA, two or more different 3HB repeating unit composition ratios can also be used in combination.

[0039] There are no particular limitations on the microorganisms that produce P3HA, as long as they possess the ability to produce P3HA. For example, Bacillus megaterium, first discovered in 1925, is known as a P3HB-producing bacterium. Other naturally occurring microorganisms include Cupriavidus necator (formerly classified as Alcaligenes eutrophus, Ralstonia eutropha, and Alcaligenes latus). These microorganisms accumulate P3HB within their cells.

[0040] Furthermore, regarding bacteria that produce copolymers of 3HB with other hydroxyalkanoates, *Aeromonas caviae* is known as a P3HB3HH producing bacterium, and *Alcaligenes eutrophus* is known as a poly(3-hydroxybutyrate-co-4-hydroxybutyrate) producing bacterium. In particular, to improve the production rate of P3HB3HH, *Alcaligenes eutrophus* strain AC32 (FERM BP-6038) with the P3HA synthase group gene introduced is preferred (T. Fukui, Y. Doi, J. Bacteriol., 179, pp4821-4830 (1997)). Microbial cells containing P3HA accumulated in the cells can be used by culturing such microorganisms under appropriate conditions. In addition to the above, recombinant microorganisms with various P3HA synthesis-related genes introduced can also be used to produce the desired P3HA, as long as the culture conditions, including the type of substrate, are optimized.

[0041] The weight-average molecular weight of PHA is not particularly limited. Preferably, the weight-average molecular weight of PHA is 50,000 to 3,000,000, more preferably 100,000 to 2,000,000, and even more preferably 150,000 to 1,500,000. When the weight-average molecular weight of PHA is 50,000 or higher, it has the advantage of reducing or avoiding the tendency for the strength of crosslinked resin particles to decrease. Alternatively, when the weight-average molecular weight of PHA is 50,000 or higher, it has the advantage of reducing or avoiding the tendency for low molecular weight components to cause stickiness. On the other hand, PHA with a weight-average molecular weight of 3,000,000 or lower has the advantage of being easy to manufacture and / or easy to manipulate to achieve the objective of one embodiment of the present invention. The weight-average molecular weight value of PHA is obtained by measuring PHA before crosslinking treatment.

[0042] The determination of the weight-average molecular weight can be performed using a gel permeation chromatography (GPC) system (Shimadzu Corporation's "High Performance Liquid Chromatography 20A System"), with polystyrene gel (Showa Denko Corporation's "KG 4A", "K-806M", etc.) as the column packing material and chloroform as the mobile phase. The weight-average molecular weight can be determined by using a standard curve obtained from measuring polystyrene with a known molecular weight using the same method, and this standard curve can be used as the weight-average molecular weight. In this case, the standard curve can be prepared using polystyrene with weight-average molecular weights of 31,400, 197,000, 668,000, and 1,920,000. For the GPC column, a column suitable for determining the above molecular weights can be used.

[0043] In this specification, "polylactic acid" refers to a resin containing repeating units represented by [-CHCH3-CO-O-] accounting for more than 50 mol% of all monomer repeating units (100 mol%). Polylactic acid may also contain repeating units represented by [-CHCH3-CO-O-] accounting for more than 60 mol%, more than 70 mol%, more than 80 mol%, or more than 90 mol% of all monomer repeating units (100 mol%).

[0044] Polylactic acid (PLA) can be any conventionally known PLA. This PLA can be crystalline, amorphous, or a mixture of both.

[0045] Polylactic acid (PLA) can be a homopolymer of lactic acid or a copolymer of lactic acid with other monomers. Alternatively, it can be a blend of a homopolymer of lactic acid with a copolymer of lactic acid and other monomers.

[0046] Other monomers mentioned above include aliphatic hydroxycarboxylic acids other than lactic acid, aliphatic polyols, aliphatic polycarboxylic acids, polyfunctional polysaccharides, and caprolactones.

[0047] There are no particular limitations on the lactic acid raw materials used to manufacture polylactic acid (PLA). The following can be used: L-lactic acid, D-lactic acid, DL-lactic acid, or mixtures thereof; as well as L-lactide, D-lactide, meso-lactide, or mixtures thereof. Lactic acid obtained from plant-derived renewable raw materials such as starch through microbial fermentation can be utilized effectively.

[0048] There are no particular limitations on the methods for manufacturing polylactic acid, such as dehydration polycondensation and ring-opening polymerization.

[0049] The weight-average molecular weight of polylactic acid (PLA) is not particularly limited, but is preferably 50,000 to 1,000,000, more preferably 70,000 to 700,000, and even more preferably 100,000 to 400,000. When the weight-average molecular weight of PLA is 50,000 or higher, the crosslinked resin particles, the resin composition containing the crosslinked resin particles, and the molded articles thereof can obtain sufficient rigidity and / or strength. On the other hand, PLA with a weight-average molecular weight of 1,000,000 or less has the advantage of being easy to manufacture and / or easy to manipulate to achieve the purpose of one embodiment of the present invention.

[0050] Examples of "polycaprolactone" include, but are not limited to, polymers obtained by ring-opening polymerization of ε-caprolactone. In one embodiment of the invention, PCL obtained by other manufacturing methods may also be used. Organometallic catalysts may also be used to promote the polymerization of PCL. In this specification, "PCL" also includes copolymers formed by copolymerizing ε-caprolactone with monomers other than ε-caprolactone (e.g., lactide and glycolic acid).

[0051] PCL typically has a melting point of 50°C to 65°C, a crystallization temperature of 10°C to 30°C, and a glass transition point of -50°C to -60°C.

[0052] The weight-average molecular weight of PCL is preferably 30,000 to 500,000, more preferably 100,000 to 400,000. When the weight-average molecular weight of PCL is 30,000 or more, the cross-linked resin particles, the resin composition containing the cross-linked resin particles, and the molded articles thereof can obtain sufficient rigidity and / or strength. When the weight-average molecular weight of PCL is 500,000 or less, the cross-linked resin particles have the advantage of being easy to process.

[0053] Commercially available PCL products include, for example, “Capa6506” (powder, Mw=130,000), “Capa6500” (granules, Mw=130,000), “Capa6806” (powder, Mw=230,000), “Capa6800” (granules, Mw=230,000), and “FB100” (granules, Mw=300,000, containing PCL crosslinking agents) manufactured by Ingevity.

[0054] Examples of aliphatic polyesters other than PHA include (i) polycaprolactone (PCL), (ii) polylactic acid (PLA), and (iii) aliphatic polyesters comprising a structure formed by the condensation polymerization of an aliphatic diol and an aliphatic dicarboxylic acid. Specific examples of aliphatic polyesters comprising a structure formed by the condensation polymerization of an aliphatic diol and an aliphatic dicarboxylic acid include polyethyl succinate, polybutyl succinate (hereinafter sometimes also referred to as "PBS"), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene adipate succinate adipate (hereinafter sometimes also referred to as "PBSA"), polyethylene sebacate, and polybutylene sebacate.

[0055] In this specification, "PBS" refers to an aliphatic polyester copolymer synthesized by esterification and / or transesterification of an aliphatic diol component with 1,4-butanediol as the main component and an aliphatic dicarboxylic acid component with succinic acid and / or its derivatives as the main component, as well as by polycondensation.

[0056] PBS, for example, contains butyl succinate repeating units represented as [-CO-(CH2)2-CO-O-(CH2)4-O-].

[0057] PBS can be manufactured using petroleum as a raw material or non-petroleum-based materials (such as plants).

[0058] In this specification, "PBS" also includes copolymers formed by copolymerizing the above-mentioned PBS with monomers other than 1,4-butanediol and succinic acid (such as L-lactic acid and / or caprolactone), i.e., "PBS-based resins".

[0059] Commercially available products can also be used as PBS. Examples of commercially available PBS include "BioPBS FZ71" and "BioPBS FZ91" manufactured by Mitsubishi Chemical Corporation.

[0060] In this specification, "PBSA" refers to an aliphatic polyester copolymer synthesized by esterification of an aliphatic diol component with 1,4-butanediol as the main component, an aliphatic dicarboxylic acid component with succinic acid and / or its derivatives as the main component, and adipic acid, followed by polycondensation.

[0061] PBSA, as long as it can achieve the effects of one embodiment of the present invention, can not only have repeating units of butanediol, succinic acid, and adipic acid, but also repeating units of optional diols other than butanediol, repeating units of optional dicarboxylic acids other than succinic acid and adipic acid, and / or repeating units of hydroxyalkanoic acid. Examples of optional diols include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanediol. Examples of optional dicarboxylic acids include octanoic acid, sebacic acid, dodecanoic acid, succinic anhydride, and adipic anhydride.

[0062] In this specification, "PBSA" also includes copolymers formed by copolymerizing the above-mentioned PBSA with monomers other than 1,4-butanediol, succinic acid and adipic acid (e.g., lactic acid, terephthalic acid, malic acid, sebacic acid and azelaic acid, selected within the range that does not impair biodegradability), namely "PBSA-based resins".

[0063] Commercially available products can also be used as PBSA. Examples of commercially available PBSA include "BioPBS FD72" and "BioPBS FD92" manufactured by Mitsubishi Chemical Corporation.

[0064] As an aliphatic polyester, one of the above-mentioned resins can be used alone, or two or more can be used in combination. Furthermore, regarding the above-mentioned resins, one of each of the above-mentioned resins can be used alone, or two or more can be used in combination.

[0065] As an example of the aliphatic aromatic polyester, an aliphatic aromatic polyester obtained by copolymerizing both aliphatic and aromatic compounds as monomers is provided.

[0066] Examples of aliphatic aromatic polyesters include polybutylene adipate terephthalate (hereinafter sometimes also called "PBAT"), polybutylene sebacic acid terephthalate (hereinafter sometimes also called "PBSeT"), polybutylene azelaic acid terephthalate (hereinafter sometimes also called "PBAzT"), polybutylene succinate terephthalate (hereinafter sometimes also called "PBST"), and polybutylene succinate adipate terephthalate (hereinafter sometimes also called "PBSAT").

[0067] In this specification, "PBAT" refers to a random copolymer formed by polymerizing 1,4-butanediol with adipic acid and terephthalic acid.

[0068] PBAT is not particularly limited, but it is preferred to be obtained by reacting the following mixtures (a) and (b) as described in Japanese Patent Publication No. 10-508640, etc.: mixture (a) mainly contains 35 to 95 mol% of adipic acid or its ester-forming derivatives or mixtures thereof, and 5 to 65 mol% of terephthalic acid or its ester-forming derivatives or mixtures thereof (the sum of the mol% is 100 mol%); mixture (b) contains butanediol.

[0069] In one embodiment of the present invention, in the manufacture of PBAT, ethylene glycol, propylene glycol, heptaethylene glycol, hexanediol, octyl glycol, nonanediol, decanediol, 1,4-cyclohexanediol, neopentyl glycol, glycerol, pentaerythritol, bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and other diol compounds may be used to replace the aforementioned 1,4-butanediol. Furthermore, in one embodiment of the present invention, in the manufacture of PBAT, oxalic acid, succinic acid, azelaic acid, dodecanoic acid, malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis(p-carboxyphenyl)methane, anthracenedicarboxylic acid, 4,4'-diphenyl ether dicarboxylic acid, sodium 5-sulfonate isophthalate, tetrabutylphosphonium 5-isophthalate, and other dicarboxylic acids may be used to replace the aforementioned adipic acid.

[0070] Commercially available products can also be used as PBATs. Examples of commercially available PBATs include the "Ecoflex C1200" manufactured by BASF.

[0071] In this specification, "PBSeT" refers to a random copolymer formed by polymerizing 1,4-butanediol with sebacic acid and terephthalic acid. Regarding various embodiments of PBSeT, embodiments may be adopted by appropriately replacing "adipic acid" and "adipic acid or its ester-forming derivatives" with "sebacic acid" and "sebacic acid or its ester-forming derivatives" respectively, based on the above-described embodiments of PBSeT.

[0072] Commercially available products can also be used as PBSeTs. Examples of commercially available PBSeTs include "Ecoflex FS blend C2200" (registered trademark) manufactured by BASF.

[0073] In this specification, "PBAzT" refers to a random copolymer formed by polymerizing 1,4-butanediol with azelaic acid and terephthalic acid. Regarding various embodiments of PBAzT, embodiments may be adopted by appropriately replacing "adipic acid" and "adipic acid or its ester-forming derivatives" with "azelaic acid" and "azelaic acid or its ester-forming derivatives" respectively, based on the above-described embodiments of PBAT.

[0074] In this specification, "PBST" refers to the polymer obtained by introducing terephthalic acid ester units into the aforementioned PBS. More specifically, "PBST" refers to an aliphatic aromatic polyester copolymer synthesized by esterification and polycondensation of an aliphatic dicarboxylic acid component, with succinic acid and / or its derivatives as the main component, and terephthalic acid.

[0075] In this specification, "PBSAT" refers to a copolymer in which the ratio of succinic acid residues: adipic acid residues: phthalic acid residues in an aliphatic dicarboxylic acid group is preferably 70-90:5-15:5-15 mol%. Therefore, to manufacture PBSAT, for example, a method can be used whereby a mixture of dicarboxylic acids containing succinic acid, adipic acid, and phthalic acid in the above ratio, and 1,4-butanediol as an aliphatic diol, are used in an esterification reaction at a molar ratio of the dicarboxylic acid mixture to the aliphatic diol of 1:1.2-2.0, followed by a polycondensation reaction. The reactive groups and reaction conditions used in the reaction can be appropriately adopted from those used in existing biodegradable resins such as PBS.

[0076] As an aliphatic aromatic polyester, one of the above-mentioned resins can be used alone, or two or more can be used in combination. Furthermore, regarding the above-mentioned resins, one of each of the above-mentioned resins can be used alone, or two or more can be used in combination.

[0077] The cross-linked resin particles contain at least a biodegradable resin (A) with a glass transition temperature below 0°C as the biodegradable resin. The cross-linked resin particles may also contain not only a biodegradable resin (A) with a glass transition temperature below 0°C, but also a biodegradable resin with a glass transition temperature above 0°C. The glass transition temperature of the resin can be easily determined by the method described in the (Glass Transition Temperature (Tg)) section of the [Examples] column described later. In other words, the cross-linked resin particles contain a biodegradable resin (A) with a glass transition temperature below 0°C as determined by the method described later.

[0078] Typically, the Tg of PHA (excluding polyglycolic acid), PCL, PBS, PBSA, PBAT, PBSeT, PBAzT, PBST, and PBSAT is below 0°C. PCL typically has a Tg of -50°C to -60°C. PBS typically has a Tg of -30°C to -40°C. PBSA typically has a Tg of -40°C to -50°C. PBAT typically has a Tg of -30°C to -40°C. PBSeT typically has a Tg of -20°C to -40°C. PBAzT typically has a Tg of -20°C to -40°C. PBST typically has a Tg of -20°C to -40°C. PBSAT typically has a Tg of -20°C to -40°C.

[0079] Typically, the temperature gradient (Tg) of polyglycolic acid (PEG) and PLA is above 0°C. PEG typically has a Tg of 35°C to 40°C. PLA typically has a Tg of 55°C to 65°C.

[0080] On the other hand, the glass transition temperature of a resin depends on the constituent units that make up the resin. Therefore, for example, polyglycolic acid, a copolymer of glycolic acid and caprolactone, may have a Tg below 0°C, depending on the caprolactone content. Similarly, polylactic acid, a copolymer of lactic acid and caprolactone, may also have a Tg below 0°C, depending on the caprolactone content. Such polyglycolic acids with a glass transition temperature below 0°C and polylactic acids with a glass transition temperature below 0°C can also be considered biodegradable resins (A).

[0081] For example, in the P3HA class, the Tg of copolymers formed by copolymerizing 3HB with monomers other than 3HB may depend on the type and proportion of monomers other than 3HB in the copolymer. As another example, P3HB3HH, where the 3HH repeating unit accounts for more than 10 mol% of all repeating units in 100 mol%, has a Tg below 0℃. Similarly, P3HB4HB, where the 4HB repeating unit accounts for more than 6 mol% of all repeating units in 100 mol%, also has a Tg below 0℃.

[0082] As the biodegradable resin (A), one of the above-mentioned resins can be used alone, or two or more can be used in combination. Furthermore, regarding the above-mentioned resins, one of each of the above-mentioned resins can be used alone, or two or more can be used in combination. Relatedly, the biodegradable resin (A) can also be: (i) composed only of one or more aliphatic polyesters; (ii) composed only of one or more aliphatic aromatic polyesters; (iii) composed only of a mixture of one or more aliphatic polyesters and one or more aliphatic aromatic polyesters; or (iv) composed of a mixture of one or more aliphatic polyesters, one or more aliphatic aromatic polyesters, and one or more resins other than aliphatic polyesters and aliphatic aromatic polyesters.

[0083] The biodegradable resin (A) preferably comprises one or more selected from (i) poly(3-hydroxybutyrate-co-4-hydroxybutyrate), (ii) poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), (iii) polycaprolactone, (iv) an aliphatic polyester comprising a structure formed by the condensation of an aliphatic diol and an aliphatic dicarboxylic acid, and (v) an aliphatic aromatic polyester, more preferably one or more selected from these (consisting only of one or more selected from these).

[0084] The cross-linked resin particles preferably contain at least 60% by weight, more preferably at least 70% by weight, further preferably at least 80% by weight, and particularly preferably at least 90% by weight, of a biodegradable resin in 100% by weight of the resin component of the cross-linked resin particles. Alternatively, the cross-linked resin particles may contain 100% by weight of a biodegradable resin in 100% by weight of the resin component of the cross-linked resin particles. In other words, the resin component of the cross-linked resin particles may consist solely of a biodegradable resin.

[0085] The cross-linked resin particles preferably contain at least 60% by weight, more preferably at least 70% by weight, further preferably at least 80% by weight, and particularly preferably at least 90% by weight, of a biodegradable resin (A) with a glass transition temperature below 0°C, comprising 100% by weight of the resin component of the cross-linked resin particles. The cross-linked resin particles may also contain 100% by weight of biodegradable resin (A) comprising 100% by weight of the resin component of the cross-linked resin particles. In other words, the resin component of the cross-linked resin particles may consist solely of biodegradable resin (A).

[0086] In one embodiment of the present invention, the following cross-linked resin particles may be excluded: cross-linked resin particles containing 50% by weight or more of P3HB3HH as biodegradable resin (A); cross-linked resin particles containing 60% by weight or more of P3HB3HH as biodegradable resin (A); cross-linked resin particles containing 70% by weight or more of P3HB3HH as biodegradable resin (A); cross-linked resin particles containing 80% by weight or more of P3HB3HH as biodegradable resin (A); and cross-linked resin particles containing 90% by weight or more of P3HB3HH as biodegradable resin (A). In another embodiment of the present invention, the cross-linked resin particles may also be free of P3HB3HH; in other words, in one embodiment of the present invention, cross-linked resin particles containing P3HB3HH may be excluded.

[0087] In one embodiment of the present invention, the following cross-linked resin particles may be excluded: cross-linked resin particles containing 50% by weight or more of P3HA as the biodegradable resin (A); cross-linked resin particles containing 60% by weight or more of P3HA as the biodegradable resin (A); cross-linked resin particles containing 70% by weight or more of P3HA as the biodegradable resin (A); cross-linked resin particles containing 80% by weight or more of P3HA as the biodegradable resin (A); and cross-linked resin particles containing 90% by weight or more of P3HA as the biodegradable resin (A). In another embodiment of the present invention, the cross-linked resin particles may also be free of P3HA; in other words, in another embodiment of the present invention, cross-linked resin particles containing P3HA may be excluded.

[0088] In one embodiment of the present invention, the following cross-linked resin particles may be excluded: cross-linked resin particles containing 50% by weight or more of PHA as the biodegradable resin (A); cross-linked resin particles containing 60% by weight or more of PHA as the biodegradable resin (A); cross-linked resin particles containing 70% by weight or more of PHA as the biodegradable resin (A); cross-linked resin particles containing 80% by weight or more of PHA as the biodegradable resin (A); and cross-linked resin particles containing 90% by weight or more of PHA as the biodegradable resin (A). In another embodiment of the present invention, the cross-linked resin particles may also be PHA-free; in other words, in another embodiment of the present invention, cross-linked resin particles containing PHA may be excluded.

[0089] (Gel fraction)

[0090] In this specification, "crosslinked resin particles" refers to particles with the following crosslinking structure: the molecular chains of the resin constituting the resin particles are bonded to each other intramolecularly and / or intermolecularly. That is, these crosslinked resin particles possess a crosslinked structure formed by the molecular chains of the biodegradable resin (A) being bonded to each other. The amount of crosslinking structure in the crosslinked resin particles affects their gel fraction; specifically, the more crosslinking structures, the higher the gel fraction. These crosslinked resin particles possess a certain amount of crosslinking structures, thus exhibiting a high gel fraction, specifically a gel fraction of 50% or more. With a gel fraction of 50% or more, these crosslinked resin particles possess excellent hardness, heat resistance, and solvent resistance.

[0091] The gel fraction is preferably 60% or more, more preferably 70% or more, further preferably 75% or more, and particularly preferably 80% or more. Alternatively, it can be 85% or more, or 90% or more. There is no particular upper limit to the gel fraction; a gel fraction of 100% or less is acceptable. From the viewpoint of production efficiency of crosslinked resin particles, the gel fraction is preferably 99.5% or less, more preferably 99% or less. Alternatively, the gel fraction can be 98% or less, 97% or less, or 96% or less.

[0092] The gel fraction was measured as follows:

[0093] (1) The dried cross-linked resin particles were added to chloroform at a concentration of 0.7% by weight, and the resulting mixture was kept at 60°C for 30 minutes to obtain a chloroform solution.

[0094] (2) Subsequently, the chloroform solution was allowed to stand at room temperature for 3 hours, and then filtered using a membrane filter with a pore size of 0.45 μm.

[0095] (3) The gel remaining on the filter was dried, and the weight of the dried gel together with the filter was measured. The gel fraction was calculated using the following formula.

[0096] Formula: Gel fraction (%) = {(Weight of filter including dried gel - Weight of filter alone) / Weight of dried crosslinked resin particles for determination} × 100.

[0097] (Median particle size (D50))

[0098] The median particle size of the crosslinked resin particles is preferably 0.10 μm to 10.00 μm. According to this design, the crosslinked resin particles can be readily used for various applications described later. From the viewpoint of practical application, the median particle size is more preferably 0.15 μm or more, and even more preferably 0.20 μm or more. Furthermore, from a production perspective (e.g., production of biodegradable resin (A) and / or crosslinking treatment), the median particle size is more preferably 8.00 μm or less, and even more preferably 5.00 μm or less.

[0099] The median particle size is a value obtained by measuring a dispersion of cross-linked resin particles in an aqueous solvent. A general-purpose measuring device can be used, such as the Microtrac MT3300EXII manufactured by Nikkiso Corporation. More specifically, the particle size at which the large diameter side and the small diameter side of the measured cumulative particle size distribution are equal in amount (50%) is defined as the "median particle size (D50)".

[0100] <Peroxides>

[0101] The cross-linking structure in these cross-linked resin particles is not particularly limited, but it is preferable to use peroxides for cross-linking. That is, these cross-linked resin particles are preferably resin particles formed by cross-linking with peroxides. If peroxides are used, the free radicals generated by the decomposition of the peroxides will act on the molecules of the resin (e.g., biodegradable resin (A)) constituting the resin particles. As a result, the molecular chains of the resin constituting the resin particles are directly bonded to each other, thereby forming a cross-linked structure.

[0102] If cross-linked resin particles are cross-linked using a peroxide, the aqueous dispersion containing these particles may sometimes contain substances derived from the peroxide used to introduce the cross-linking structure (decomposition products of the peroxide and unreacted peroxides, etc.). Alternatively, if the cross-linked resin particles are cross-linked using a peroxide, the surface of the resulting cross-linked resin particles may sometimes be adhered with substances derived from the peroxide used to introduce the cross-linking structure (decomposition products of the peroxide and unreacted peroxides, etc.). In other words, if cross-linked resin particles are cross-linked using a peroxide, they may contain substances derived from the peroxide (decomposition products of the peroxide and unreacted peroxides, etc.). If the cross-linked resin particles contain substances derived from the peroxide, analysis of these particles will confirm that they are cross-linked using a peroxide.

[0103] The peroxide can be an organic peroxide or an inorganic peroxide. The peroxide is preferably an organic peroxide, which can more effectively improve the gel fraction.

[0104] Taking into account the heating temperature and / or time during the crosslinking process, it is preferable to use at least one of the following organic peroxides: diacyl peroxide, alkyl peroxide, dialkyl peroxide, hydrogen peroxide, peroxide ketal, peroxy carbonate, and peroxy dicarbonate.

[0105] Examples of such organic peroxides include: butyl peroxyneodecayl, octanoyl peroxide, dilauroyl peroxide, succinic acid peroxide, a mixture of tolueneyl peroxide and benzoyl peroxide, benzoyl peroxide, bis(butylperoxy)trimethylcyclohexane, butyl peroxylaurate, dimethyldi(benzoylperoxy)hexane, bis(butylperoxy)methylcyclohexane, bis(butylperoxy)cyclohexane, butyl peroxybenzoate, butyl bis(butylperoxy)valerate, dicumyl peroxide, ditert-hexyl peroxide, tert-butyl 2-ethylperoxyhexanoate, tert-butyl peroxyisobutyrate, tert-butyl peroxyneopentarate, tert-hexyl peroxyneopentarate, tert-butyl peroxymonocarbonate, tert-butyl peroxymonocarbonate, tert-amyl peroxymonocarbonate, etc. Methyl peroxide monocarbonate tert-hexyl ester, methyl peroxide monocarbonate tert-heptyl ester, methyl peroxide monocarbonate tert-octyl ester, methyl peroxide monocarbonate 1,1,3,3-tetramethylbutyl ester, ethyl peroxide monocarbonate tert-butyl ester, ethyl peroxide monocarbonate tert-pentyl ester, ethyl peroxide monocarbonate tert-hexyl ester, ethyl peroxide monocarbonate tert-octyl ester, ethyl peroxide monocarbonate 1,1,3,3-tetramethylbutyl ester, n-propyl peroxide tert-butyl ester, n-propyl peroxide monocarbonate tert-pentyl ester, n-propyl peroxide monocarbonate tert-hexyl ester, n-propyl peroxide monocarbonate tert-heptyl ester, n-propyl peroxide monocarbonate tert-octyl ester, n-propyl peroxide monocarbonate 1,1,3,3-tetramethylbutyl ester, isopropyl peroxide monocarbonate tert-butyl ester, isopropyl peroxide monocarbonate tert-pentyl ester, ... Isopropyl carbonate tert-hexyl ester, Isopropyl peroxymonocarbonate tert-heptyl ester, Isopropyl peroxymonocarbonate tert-octyl ester, Isopropyl peroxymonocarbonate 1,1,3,3-tetramethylbutyl ester, Isopropyl peroxymonocarbonate n-butyl tert-butyl ester, Isopropyl peroxymonocarbonate n-butyl tert-pentyl ester, Isopropyl peroxymonocarbonate tert-hexyl ester, Isopropyl peroxymonocarbonate n-butyl tert-octyl ester, Isopropyl peroxymonocarbonate 1,1,3,3-tetramethylbutyl ester, Isopropyl peroxymonocarbonate tert- ... Butyl ester, sec-butyl ...3-Tetramethylbutyl ester, diisobutyl peroxide, cumyl peroxyneodecanate, di-n-propyl peroxydicarbonate, diisopropyl peroxydicarbonate, di-sec-butyl peroxydicarbonate, 1,1,3,3-tetramethylbutyl peroxyneodecanate, bis(4-tert-butylcyclohexyl peroxydicarbonate), bis(2-ethylhexyl peroxydicarbonate), tert-hexyl peroxyneodecanate, tert-butyl peroxyneodecanate, tert-butyl peroxyneoheptanoate, tert-hexyl peroxyneopentaate, tert-butyl peroxyneopentaate, di(3,5,5-trimethylhexanoyl peroxide), dilauroyl peroxide, 1,1,3,3-tetramethylbutyl peroxyhexanoate, peroxy Examples of organic peroxides include disuccinic acid, 2,5-dimethyl-2,5-bis(2-ethylhexanoylperoxy)hexane, tert-hexyl 2-ethylperoxyhexanoate, bis(4-methylbenzoyl peroxide), benzoyl peroxide, tert-butyl 2-ethylhexyl percarbonate, tert-butyl isopropyl percarbonate, 1,6-bis(tert-butylperoxycarbonyl)hexane, tert-butyl 3,5,5-trimethylperoxyhexanoate, tert-butyl peracetate, tert-butyl peroxybenzoate, tert-amyl 3,5,5-trimethylperoxyhexanoate, 2,2-bis(4,4-di-tert-butylperoxycyclohexyl)propane, and 2,2-di-tert-butylperoxybutane. Organic peroxides can be used alone or in combination of two or more.

[0106] Among these, tert-butyl peroxymonocarbonate, tert-pentyl peroxymonocarbonate, tert-hexyl peroxymonocarbonate, tert-butyl 2-ethylhexyl peroxymonocarbonate, tert-pentyl 2-ethylhexyl peroxymonocarbonate, tert-hexyl 2-ethylhexyl peroxymonocarbonate, tert-pentyl peroxymonocarbonate, di-tert-hexyl peroxide, tert-butyl 2-ethylperoxyhexanoate, tert-butyl peroxyisobutyrate, tert-hexyl 2-ethylperoxyhexanoate, 1,1,3,3-tetramethylbutyl 2-ethylperoxyhexanoate, tert-butyl peroxyneoplastate, tert-hexyl peroxyneoplastate, tert-butyl peroxyneoplastate, tert-hexyl peroxyneoplastate, and 1,1,3,3-tetramethylbutyl peroxyneoplastate are preferred organic peroxides because they can effectively promote the crosslinking of the resins constituting the resin particles.

[0107] For the purpose of setting a lower heating temperature during the crosslinking process, among the above-mentioned peroxides, compounds with a 1-hour half-life temperature of 200°C or lower are preferred, compounds with a 1-hour half-life temperature of 170°C or lower are more preferred, and compounds with a 1-hour half-life temperature of 140°C or lower are even more preferred. The 1-hour half-life temperature of the peroxide can be 50°C or higher, 60°C or higher, or 70°C or higher.

[0108] As an organic peroxide exhibiting this 1-hour half-life temperature, the following are particularly preferred: tert-butyl peroxymonocarbonate, tert-butyl peroxymonocarbonate, disec-butyl peroxydicarbonate, tert-butyl peroxyhexanoate, tert-butyl peroxyisobutyrate, tert-hexyl peroxyhexanoate, 1,1,3,3-tetramethyl butyl peroxyhexanoate, tert-butyl peroxyneoplastate, tert-hexyl peroxyneoplastate, tert-butyl peroxyneodecanate, tert-hexyl peroxyneodecanate, and 1,1,3,3-tetramethyl butyl peroxyneodecanate.

[0109] The case where the aforementioned peroxide is an inorganic peroxide will be explained. Considering the heating temperature and / or time during the crosslinking process, examples of such inorganic peroxides include hydrogen peroxide, potassium peroxide, calcium peroxide, sodium peroxide, magnesium peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate. Among these, hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate are preferred from the viewpoint of ease of operation and having a decomposition temperature suitable for the heating temperature during the crosslinking process. One inorganic peroxide can be used alone, or two or more can be used in combination. Furthermore, organic peroxides and inorganic peroxides can also be used in combination.

[0110] <Multifunctional Compounds>

[0111] The cross-linking structure in this cross-linked resin particle can be introduced using only peroxide, or by using both peroxide and a multifunctional compound simultaneously. That is, the cross-linked resin particle can also be formed in the presence of both peroxide and a multifunctional compound. When both peroxide and a multifunctional compound are used simultaneously, a smaller amount of peroxide can be used to increase the gel fraction of the cross-linked resin particle compared to using only peroxide.

[0112] The multifunctional compound refers to a compound having two or more functional groups (e.g., free radical reactive groups) in one molecule that are capable of crosslinking the resin (e.g., biodegradable resin (A)) constituting the resin particles. While there is no particular limitation on the multifunctional compound, it is preferably a compound that reacts with free radicals generated by peroxides, and particularly preferably a compound having two or more free radical reactive groups in one molecule. The free radical reactive group is preferably selected from at least one of vinyl, allyl, acryloyl, and methacryloyl groups.

[0113] Such multifunctional compounds are not particularly limited, but examples include: allyl methacrylates; allyl alkyl methacrylates; allyloxyalkyl methacrylates; ethylene glycol dimethacrylate, butylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, pentaerythritol methacrylate, and other multifunctional (meth)acrylates having two or more (meth)acryloyl groups; divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, divinylbenzene, etc. Preferably, the compounds are selected from one or more of allyl methacrylate, triallyl isocyanurate, butylene glycol dimethacrylate, and divinylbenzene, and particularly preferably, they are selected from one or more of allyl methacrylate and triallyl isocyanurate.

[0114] If a cross-linked structure is formed in the presence of a multifunctional compound, the resulting cross-linked resin particles typically contain structures derived from that multifunctional compound. In this case, the molecular chains of the resin constituting the resin particles are linked together by structures derived from the multifunctional compound.

[0115] The cross-linked resin particles may consist solely of a biodegradable resin (A) having a cross-linked structure, or may include components other than the biodegradable resin (A) having a cross-linked structure. Examples of components other than the biodegradable resin (A) having a cross-linked structure include, for instance, the aforementioned biodegradable resin with a glass transition temperature of 0°C or higher, resins other than biodegradable resins, antioxidants, hydrolysis inhibitors, anti-blocking agents, crystallizing nucleating agents, lubricants, and ultraviolet absorbers.

[0116] The cross-linked resin particles are preferably non-foamed resin particles, unlike the foamed resin particles disclosed in International Publication Nos. 2007 / 049694 and 2019 / 146555. In other words, the cross-linked resin particles are preferably substantially free of air bubbles inside. "Substantially free of air bubbles inside" means that the volume of air bubbles (voids) in 100% of the cross-linked resin particle volume is less than 10%.

[0117] When the cross-linked resin particles are not foamed, they exhibit a relatively high apparent density. Preferably, the apparent density of these cross-linked resin particles exceeds 0.6 g / cm³. 3 More preferably 0.7 g / cm³ 3 The above is further preferred to be 0.9 g / cm³. 3The apparent density of cross-linked resin particles can be determined by the methods described in JIS K0061 (Determination of density and specific gravity of chemical products) or JIS Z8807 (Determination of density and specific gravity of solids).

[0118] There is no particular limitation on the average weight of each cross-linked resin particle. For example, when the median particle size of the cross-linked resin particles is less than 10.00 μm, the average weight of each cross-linked resin particle may be much lower than 0.1 mg.

[0119] These cross-linked resin particles can be dried. The shape after drying varies depending on the drying method; they can be in the form of powder, granules, fragments, film, or flakes.

[0120] <Aqueous Dispersion>

[0121] In one embodiment of the present invention, an aqueous dispersion is provided, which is formed by dispersing the crosslinked resin particles in an aqueous medium.

[0122] The aqueous dispersion may contain only water, or it may be a mixture of water and an organic solvent that is miscible with water. In this mixture, the concentration of the organic solvent that is miscible with water is simply below the solubility of the organic solvent relative to water, and is not particularly limited.

[0123] The organic solvent is not particularly limited, and examples include: alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, pentanol, hexanol, and heptanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; nitriles such as acetonitrile and propionitrile; amides such as dimethylformamide and acetamide; dimethyl sulfoxide; pyridine; and piperidine. From the viewpoint of easy removal, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, acetonitrile, and propionitrile are preferred. From the viewpoint of easy availability, methanol, ethanol, 1-propanol, 2-propanol, butanol, and acetone are more preferred. Furthermore, methanol, ethanol, and acetone are particularly preferred.

[0124] The water content in the total aqueous medium (100 wt%) constituting the above-mentioned aqueous dispersion is preferably 5 wt% to 100 wt%. More preferably, the water content in 100 wt% of the aqueous medium is 10 wt% or more, more preferably 30 wt% or more, even more preferably 50 wt% or more, and particularly preferably 70 wt% or more. The water content in 100 wt% of the aqueous medium can be 90 wt% or more, or 95 wt% or more.

[0125] The concentration of the crosslinked resin particles in the above-described aqueous dispersion is not particularly limited, but may be, for example, 1% to 60% by weight. Furthermore, the aqueous dispersion may also contain the dispersant described later.

[0126] <Method for manufacturing cross-linked resin particles>

[0127] The following describes one example of a method for manufacturing these cross-linked resin particles. These cross-linked resin particles can be obtained by cross-linking the molecular chains of the resin with each other in an aqueous dispersion containing the resin particles before cross-linking treatment, in the presence of a peroxide. Furthermore, "resin particles" refers to particles composed of the resin components that substantially constitute the cross-linked resin particles. When the resin component consists only of PHA, the resin particles can also be called PHA particles. To achieve efficient cross-linking of the resin molecular chains, it is preferable to heat the aqueous dispersion of resin particles containing the peroxide to a temperature suitable for the decomposition of the peroxide.

[0128] More specifically, the method for manufacturing the crosslinked resin particles preferably includes: a step (1) of preparing an aqueous dispersion of resin particles (e.g., PHA particles) dispersed in water; a step (2) of adding a peroxide to the aqueous dispersion of resin particles to impregnate the resin particles with the peroxide; and a step (3) of heating the aqueous dispersion of resin particles impregnated with the peroxide to a heating temperature to crosslink the molecular chains of the resin (e.g., the molecular chains of PHA) with each other. More preferably, it further includes a step (4) of maintaining the heating temperature after all the peroxide has been added.

[0129] In step (1), for example, the aqueous dispersion of PHA particles can be obtained by: culturing PHA-producing microorganisms to accumulate PHA within the cells, then disintegrating the cells in the culture medium and separating and removing the cell components; or by concentrating or diluting the aqueous dispersion to obtain an aqueous dispersion. According to this method, the process from obtaining PHA particles by culturing PHA-producing microorganisms to the crosslinking treatment can be carried out without separating the PHA particles from the water.

[0130] In addition, an aqueous dispersion of resin particles (e.g., PHA particles) can also be prepared by dispersing dried resin particles (e.g., PHA particles) in water.

[0131] The aqueous dispersion may contain only water, or it may be a mixture of water and an organic solvent that is miscible with water. In this mixture, the concentration of the organic solvent that is miscible with water is simply below the solubility of the organic solvent relative to water, and is not particularly limited.

[0132] The organic solvent is not particularly limited, and examples include: alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, pentanol, hexanol, and heptanol; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran and dioxane; nitriles such as acetonitrile and propionitrile; amides such as dimethylformamide and acetamide; dimethyl sulfoxide; pyridine; and piperidine. From the viewpoint of easy removal, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, acetonitrile, and propionitrile are preferred. From the viewpoint of easy availability, methanol, ethanol, 1-propanol, 2-propanol, butanol, and acetone are more preferred. Furthermore, methanol, ethanol, and acetone are particularly preferred.

[0133] The water content in the total aqueous medium (100 wt%) constituting the above-mentioned aqueous dispersion is preferably 5 wt% to 100 wt%. More preferably, the water content in 100 wt% of the aqueous medium is 10 wt% or more, more preferably 30 wt% or more, even more preferably 50 wt% or more, and particularly preferably 70 wt% or more. The water content in 100 wt% of the aqueous medium can be 90 wt% or more, or 95 wt% or more.

[0134] In the aqueous dispersion, the median particle size of the resin particles is preferably within the same range as the median particle size of the aforementioned crosslinked resin particles. Regarding PHA particles produced by PHA-producing microorganisms, their median particle size is generally within the aforementioned range; therefore, even without performing special processes to adjust the particle size, an aqueous dispersion of PHA particles with a desired median particle size can be obtained.

[0135] The concentration of resin particles in the aqueous dispersion is not particularly limited and can be set appropriately, but for example it can be about 1 to 70% by weight, preferably about 5 to 50% by weight.

[0136] The aqueous dispersion of resin particles preferably contains a dispersant, thereby improving the dispersibility of the resin particles and ensuring uniform crosslinking reaction. Examples of dispersants include: anionic surfactants such as sodium dioctyl sulfosuccinate, sodium dodecyl sulfate, sodium lauryl sulfate, and sodium oleate; cationic surfactants such as lauryl trimethylammonium chloride; nonionic surfactants such as glycerol fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, and polyoxyethylene polyoxypropylene glycol; and water-soluble polymers such as polyvinyl alcohol, ethylene-modified polyvinyl alcohol, polyvinylpyrrolidone, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, polyacrylic acid, sodium polyacrylate, potassium polyacrylate, polymethacrylic acid, and sodium polymethacrylate. Only one of these dispersants may be used, or two or more may be used in combination.

[0137] If a dispersant is used, there is no particular limitation on the content (amount) of the dispersant in the aqueous dispersion. The content of the dispersant in the aqueous dispersion relative to 100 parts by weight of resin particles can be, for example, 0.1 parts by weight to 10 parts by weight, preferably 0.5 parts by weight to 5 parts by weight, and particularly preferably 0.5 parts by weight to 3 parts by weight.

[0138] In step (2), a peroxide is added to the aqueous dispersion of resin particles obtained in step (1) to allow the peroxide to permeate the resin particles. The peroxide described above can be used. The peroxide can be added in various forms, such as solid or liquid. Furthermore, it can also be added as a liquid prepared by dilution with a diluent. The peroxide can be added all at once, continuously, or in batches.

[0139] If the peroxide and the aforementioned multifunctional compound are used together, it is preferable to add the multifunctional compound to the aqueous dispersion of resin particles in step (2). The aforementioned multifunctional compound can be used as the multifunctional compound. The multifunctional compound can be added in various forms, such as solid or liquid. Furthermore, it can also be added as a liquid prepared by dilution with a diluent. The multifunctional compound can be added all at once, continuously, or in stages.

[0140] In step (2), as a method for impregnating the peroxide and optionally the multifunctional compound into the resin particles, an example can be given as follows: after adding these compounds to the aqueous dispersion of the resin particles, or while adding these compounds, the temperature of the aqueous dispersion is controlled to, for example, above 0°C and below the temperature suitable for peroxide decomposition used in the subsequent step (3), and this temperature is maintained, for example, for about 1 minute to 5 hours while stirring the aqueous dispersion. Specifically, the temperature of the aqueous dispersion during impregnation can be about 0°C to 80°C, or about 10°C to 60°C.

[0141] The amount of peroxide can be appropriately set according to the desired gel fraction of the crosslinked resin particles. For example, the amount of peroxide is preferably 0.01 parts to 10 parts by weight relative to 100 parts by weight of resin particles, more preferably 0.1 parts to 8 parts by weight, further preferably 0.3 parts to 5 parts by weight, and particularly preferably 0.5 parts to 3 parts by weight.

[0142] A manufacturing method that uses peroxides to crosslink resin particles in an aqueous dispersion allows for easy crosslinking while maintaining the particle size (volume) before crosslinking, resulting in crosslinked resin particles. On the other hand, methods that crosslink resins through melt mixing in the presence of peroxides sometimes fail to achieve the same effect.

[0143] In addition, the manufacturing method that uses peroxide to crosslink resin particles in an aqueous dispersion has the following advantages: it is easy to control the temperature rise caused by the heat generated during the crosslinking reaction, and it is possible to efficiently obtain crosslinked resin particles with a safe and stable crosslinked structure (quality).

[0144] Furthermore, the amount of the multifunctional compound can be appropriately set according to the desired gel fraction of the crosslinked resin particles. For example, the amount of the multifunctional compound relative to 100 parts by weight of the resin particles is preferably 0.01 parts by weight to 20 parts by weight, more preferably 0.05 parts by weight to 15 parts by weight, even more preferably 0.1 parts by weight to 10 parts by weight, even more preferably 0.2 parts by weight to 5 parts by weight, and particularly preferably 0.3 parts by weight to 3 parts by weight.

[0145] In step (3), the aqueous dispersion of resin particles impregnated with peroxide is heated to a temperature suitable for peroxide decomposition. The heating temperature is preferably within a range of approximately 25°C above and below the 1-hour half-life temperature exhibited by the aforementioned peroxide (1-hour half-life temperature -25°C to 1-hour half-life temperature +25°C). Specifically, the heating temperature is preferably 30°C to 140°C, more preferably 50°C to 135°C, and even more preferably 60°C to 130°C. According to this method, the resin can be crosslinked at a temperature lower than the melting temperature of the resin (e.g., PHA), thus avoiding resin deterioration caused by heating during the crosslinking process. Furthermore, the melting temperature of PHA is, for example, 50°C to 210°C.

[0146] In the subsequent step (4), it is preferable to maintain the heating temperature. This allows the crosslinking reaction, when using peroxide, to proceed sufficiently. The duration of maintaining the heating temperature is not particularly limited, but is preferably 1 minute to 15 hours, more preferably 1 hour to 10 hours.

[0147] After the crosslinking reaction is complete, dried crosslinked resin particles can be obtained by separating the crosslinked resin particles from the aqueous dispersion and removing water from the separated particles. There are no particular limitations on the method for separating the crosslinked resin particles from the aqueous dispersion; for example, filtration, centrifugation, heat drying, freeze drying, and spray drying can be used. For example, when using spray drying, dried crosslinked resin particles can be obtained directly from the aqueous dispersion. Furthermore, after separating the crosslinked resin particles from the aqueous dispersion, granular crosslinked resin particles can be obtained by extruding the crosslinked resin particles individually, while completely removing residual water. Additionally, a coagulation process using a coagulant and / or adjusting the pH can also be implemented.

[0148] The aqueous dispersion after the crosslinking reaction is completed, or an aqueous dispersion obtained by concentrating the aqueous dispersion after the crosslinking reaction to increase the concentration of crosslinking resin particles, or an aqueous dispersion diluted by adding an aqueous medium after the crosslinking reaction, also constitutes a method of the present invention. Additionally, (i) an aqueous dispersion with adjusted pH, and / or (ii) an aqueous dispersion with added dispersants, antioxidants, hydrolysis inhibitors, anti-blocking agents, crystallization nucleating agents, ultraviolet absorbers, or other additives, also constitute a method of the present invention.

[0149] <Applications of Cross-linked Resin Particles>

[0150] The uses of the crosslinked resin particles according to one embodiment of the present invention are not particularly limited, and can be used for applications previously known to be applicable to crosslinked resin particles. Specifically, they can be used, for example, as resin modifiers, rheology modifiers for coatings or adhesives, paint pigments, paper coating agents, matting agents, anti-blocking agents, cosmetic additives, printing additives, liquid crystal spacers, coating agents, tape fillers, fiber processing agents, particles for medical diagnostic examinations, fillers, water-based coatings, coated paper, resin tubes, foamed particles, packaging materials, containers, cosmetic containers, antifouling resin compositions, heat-sealing paper, handle molded bodies, forks, films, resin films for twisted packaging materials, bags, gloves, bundling materials, multilayer films, stretch films, fibers, multifilaments, meltblown nonwoven fabrics, masks, fleece fabrics, coffee filter bags, blow-molded bodies, blow-molded bodies, calendered sheet molded bodies, injection-molded bodies, laminates, films, sheets, etc. The uses of the crosslinked resin particles are not limited to these.

[0151] [2. Resin Composition]

[0152] The thermoplastic resin composition of one embodiment of the present invention comprises a thermoplastic resin and the cross-linked resin particles described in the aforementioned [1. Cross-linked resin particles] section.

[0153] In this specification, "the thermoplastic resin composition of one embodiment of the present invention" is sometimes referred to as "the resin composition".

[0154] Because of the aforementioned technical configuration, this resin composition can fully achieve the improved mechanical strength, such as impact strength, resulting from the cross-linked resin particles. Consequently, the molded articles of this thermoplastic resin composition exhibit excellent impact resistance.

[0155] A molded body can be obtained by molding the thermoplastic resin composition using a known method.

[0156] The content of cross-linked resin particles in this resin composition is not particularly limited. The content of cross-linked resin particles in this resin composition may be 0.1 parts by weight or more, 0.3 parts by weight or more, 0.5 parts by weight or more, 1 part by weight or more, 5 parts by weight or more, 7 parts by weight or more, 10 parts by weight or more, 20 parts by weight or more, 25 parts by weight or more, or 30 parts by weight or more, out of a total of 100 parts by weight of thermoplastic resin and cross-linked resin particles. The content of cross-linked resin particles in this resin composition is preferably 60 parts by weight or less, more preferably 55 parts by weight or less, further preferably 53 parts by weight or less, and particularly preferably 50 parts by weight or less, out of a total of 100 parts by weight of thermoplastic resin and cross-linked resin particles. The content of cross-linked resin particles in this resin composition may be less than 45 parts by weight, less than 40 parts by weight, less than 30 parts by weight, less than 20 parts by weight, less than 15 parts by weight, less than 12 parts by weight, or less than 10 parts by weight in a total of 100 parts by weight of thermoplastic resin and cross-linked resin particles.

[0157] <Thermoplastic Resins>

[0158] In this resin composition, the thermoplastic resin can also be referred to as the matrix resin. There are no particular limitations on the thermoplastic resin, as long as it is a resin that can be melted by heating and then cured by cooling to form a desired shape. Specific examples of thermoplastic resins include polyolefin resins such as polyethylene and polypropylene, polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, acrylic resins such as polymethyl methacrylate, AS resin, polyamide, polyoxymethylene, polycarbonate, modified polyphenylene ether, polyester resins, and cyclic polyolefins. Only one of these thermoplastic resins can be used, or two or more can be used in combination. The gel fraction of the thermoplastic resin is preferably less than 50%. The thermoplastic resin is preferably uncrosslinked.

[0159] Polyester-based resins are particularly preferred as thermoplastic resins. Examples of such polyester-based resins include aliphatic polyesters (such as PHA, PLA, PCL, and aliphatic polyesters containing structures formed by the condensation of aliphatic diols and aliphatic dicarboxylic acids) and aliphatic aromatic polyesters.

[0160] The specific methods for aliphatic polyesters and aliphatic aromatic polyesters are the same as those described in the aforementioned <Biodegradable Resins (A)> section, therefore the relevant records are cited and their descriptions are omitted here.

[0161] Since the crosslinked resin particles contain a biodegradable resin (A), the thermoplastic resin preferably also contains a biodegradable resin, i.e., a biodegradable resin. For ease of explanation, the biodegradable resin contained in the thermoplastic resin is sometimes referred to as "biodegradable resin (B)". In other words, the thermoplastic resin preferably contains biodegradable resin (B). According to this approach, it has the advantage of improving the overall biodegradability of the thermoplastic resin composition and the overall biodegradability of the molded body of the thermoplastic resin composition.

[0162] The biodegradable resin (B) contained in the thermoplastic resin can be a biodegradable resin with a glass transition temperature below 0°C, a biodegradable resin with a glass transition temperature above 0°C, or a mixture of a biodegradable resin with a glass transition temperature below 0°C and a biodegradable resin with a glass transition temperature above 0°C. For the purpose of maximizing the effects of the cross-linked resin particle formulation (e.g., improved impact resistance), the biodegradable resin (B) contained in the thermoplastic resin preferably includes a biodegradable resin with a glass transition temperature above 0°C. The biodegradable resin (B) contained in the thermoplastic resin preferably comprises: 50% or more by weight, more preferably 60% or more by weight, further preferably 70% or more by weight, and particularly preferably 80% or more by weight of a biodegradable resin with a glass transition temperature above 0°C, out of 100% by weight. The biodegradable resin (B) may also consist solely of a biodegradable resin with a glass transition temperature above 0°C.

[0163] Furthermore, when the crosslinked resin particles contain resin made from plant-derived raw materials, from the viewpoint of resource recycling, the thermoplastic resin preferably also contains resin made from plant-derived raw materials, and more preferably consists only of resin made from plant-derived raw materials.

[0164] The following describes a scheme where the thermoplastic resin includes a biodegradable resin (B). Preferably, the thermoplastic resin includes 10% to 100% by weight of the biodegradable resin (B) in 100% by weight of the thermoplastic resin. More preferably, the thermoplastic resin includes 30% or more by weight, more preferably 50% or more by weight, even more preferably 70% or more by weight, and particularly preferably 90% or more by weight of the biodegradable resin (B) in 100% by weight of the thermoplastic resin. The thermoplastic resin may also consist solely of the biodegradable resin (B).

[0165] For the reason that the thermoplastic resin composition and its molded body can obtain more of the impact resistance improvement effect brought about by cross-linked resin particles, the biodegradable resin (B) preferably includes a polyester resin, more preferably an aliphatic polyester, and particularly preferably includes PHA and / or polylactic acid. Here, the PHA used as the thermoplastic resin preferably has a gel fraction of less than 50%. In addition, the PHA used as the thermoplastic resin preferably does not have a cross-linked structure.

[0166] Therefore, an embodiment of the thermoplastic resin comprising PHA and / or polylactic acid as a biodegradable resin (B) will be described. The thermoplastic resin preferably comprises PHA and polylactic acid comprising a total of 10% to 100% by weight, more preferably 30% or more by weight, further preferably 50% or more by weight, even more preferably 70% or more by weight, and particularly preferably 90% or more by weight in 100% of the thermoplastic resin.

[0167] There are no particular limitations on the types of PHAs that can be used as thermoplastic resins; examples include polyglycolic acid, P3HA, and poly(4-hydroxyalkanoate) resins. Only one type of PHA can be used, or two or more can be used in combination. Among PHAs used as thermoplastic resins, P3HA is particularly preferred.

[0168] The following describes a scheme where both the crosslinked resin particles and the thermoplastic resin contain P3HA. The P3HA that can be used as the thermoplastic resin can be any of the aforementioned P3HAs, just as the P3HA in the crosslinked resin particles. The P3HA contained in the thermoplastic resin can be a resin with the same composition as the P3HA contained in the crosslinked resin particles, or it can be a resin with a different composition and / or properties. Preferably, the P3HA contained in the thermoplastic resin has a different composition and / or properties than the P3HA-containing resin in the crosslinked resin particles, and more preferably, it is a resin that is harder than the P3HA contained in the crosslinked resin particles.

[0169] The following describes a scheme for P3HA, used as a thermoplastic resin, containing repeating units of 3-hydroxybutyric acid (3HB). In this case, from the viewpoint of balancing flexibility and strength, the composition ratio of 3HB repeating units in all monomer repeating units (100 mol%) of P3HA is preferably 80 mol% to 99 mol%, more preferably 82 mol% to 97 mol%. When the composition ratio of 3HB repeating units in P3HA is 80 mol% or more, the rigidity of P3HA is further improved. On the other hand, when the composition ratio of 3HB repeating units in P3HA is 99 mol% or less, P3HA tends to have further improved flexibility. As P3HA, two or more types with different composition ratios of 3HB repeating units can also be used together.

[0170] The weight-average molecular weight of the PHA used as a thermoplastic resin is not particularly limited, but is preferably 50,000 to 3,000,000, more preferably 100,000 to 2,000,000, and even more preferably 150,000 to 1,500,000. When the weight-average molecular weight of the PHA is 50,000 or higher, the resin composition and its molded articles can obtain sufficient rigidity and / or strength. On the other hand, PHA with a weight-average molecular weight of 3,000,000 or less has the advantages that the PHA is easier to manufacture and / or easier to handle to achieve the object of one embodiment of the present invention.

[0171] Regarding PHA and polylactic acid used as thermoplastic resins, the methods other than those described above are the same as those described in the aforementioned <Biodegradable Resins (A)> section, therefore the relevant records are cited and their descriptions are omitted here.

[0172] The content of thermoplastic resin in this resin composition is not particularly limited. Preferably, the content of thermoplastic resin in this resin composition is 40 parts by weight to 99.9 parts by weight, more preferably 40 parts by weight to 99.7 parts by weight, even more preferably 40 parts by weight to 99.5 parts by weight, even more preferably 40 parts by weight to 99 parts by weight, and even more preferably 40 parts by weight to 95 parts by weight, out of a total of 100 parts by weight of thermoplastic resin and crosslinked resin particles. According to this embodiment, the thermoplastic resin composition can be used to provide molded articles with excellent impact resistance. The content of thermoplastic resin in this resin composition may also be 45 parts by weight to 93 parts by weight, 47 parts by weight to 90 parts by weight, 50 parts by weight to 80 parts by weight, 50 parts by weight to 75 parts by weight, or 50 parts by weight to 70 parts by weight, out of a total of 100 parts by weight of thermoplastic resin and crosslinked resin particles. The content of thermoplastic resin in this resin composition may be 55 parts by weight or more, 60 parts by weight or more, 70 parts by weight or more, 80 parts by weight or more, 85 parts by weight or more, 88 parts by weight or more, or 90 parts by weight or more, out of a total of 100 parts by weight of thermoplastic resin and crosslinked resin particles.

[0173] <Crystallization nucleating agent>

[0174] This resin composition may further contain a nucleating agent. By including a nucleating agent in the above-mentioned thermoplastic resin composition, crystallization during molding can be promoted when the thermoplastic resin is a crystalline resin, thereby improving molding processability, productivity, etc. When this resin composition contains a nucleating agent, it also has the advantage of obtaining a thermoplastic resin composition and its molded articles with excellent heat resistance or mechanical properties.

[0175] The nucleating agent is not particularly limited, and conventionally known nucleating agents can be used. Examples of nucleating agents include: inorganic substances such as talc, kaolinite, montmorillonite, mica, synthetic mica, clay, zeolite, silicon dioxide, carbon black, graphite, boron nitride, zinc oxide, titanium dioxide, tin oxide, calcium carbonate, magnesium carbonate, aluminum oxide, neodymium oxide, barium sulfate, sodium chloride, and metal phosphates; naturally derived sugar alcohols such as erythritol, pentaerythritol, galactitol, mannitol, and arabinitol; polysaccharides such as chitin and chitosan; aliphatic alcohols (polyols), polyvinyl alcohol, and polyethylene oxide; and sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, and magnesium benzoate. Barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, sodium octacosanate, calcium octacosanate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanate, calcium montanate, sodium benzoate, sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthylcarboxylate, sodium cyclohexanecarboxylate, and other organocarboxylic acid metal salts; sodium p-toluenesulfonate, sodium sulfoisophthalate, and other organosulfonates; ethylidene stearyl... Amines, ethylene dilaurate, palmitamide, hydroxystearamide, erucamide, tris(tert-butylamide) and other carboxylic amides; laurate, palmitate, oleate, stearate, erucic acid, N-oleopalmitate, N-oleooleate, N-oleostearate, N-stearyloleate, N-stearylstearate, N-stearylerucic acid, methylene distearate, ethylene dilaurate, ethylene didecanoate, ethylene dioleate, ethylene distearate, ethylene dierucic acid, ethylene diisostearate, butylene distearate, distearate Carboxylic acid esters such as p-dimethyl benzyl ester; dicarboxylic acid derivatives such as dimethyl adipate, dibutyl adipate, diisodecyl adipate, and dibutyl sebacate; cyclic compounds with functional groups such as C=O (found in indigo, quinacridone, and quinacridone fuchsin) and one or more functional groups selected from NH, S, and O; sorbitol derivatives such as dibenzylidene sorbitol and bis(p-methylenebenzylidene)sorbitol; compounds containing nitrogen-containing aromatic nuclei such as pyridine, triazine, and imidazole; phosphate esters, higher fatty acid diamides, and higher fatty acid metal salts; branched polylactic acid; and low molecular weight poly3-hydroxybutyrate, etc. These nucleating agents can be used alone or in combination of two or more.

[0176] The content of the nucleating agent is not particularly limited as long as it promotes the crystallization of the thermoplastic resin. The content of the nucleating agent is preferably 0.05 parts by weight to 12.00 parts by weight relative to 100 parts by weight of the thermoplastic resin, more preferably 0.10 parts by weight to 10.00 parts by weight, and even more preferably 0.50 parts by weight to 8.00 parts by weight. When the content of the nucleating agent is within the above range, the viscosity and physical properties of the molded article during molding can be suppressed, and the corresponding effects of the nucleating agent can be achieved.

[0177] Lubricant

[0178] This resin composition may further contain a lubricant. By containing a lubricant in the above-mentioned thermoplastic resin composition, the surface smoothness of the resulting molded article can be improved. The lubricant is not particularly limited. Examples of the lubricant include: fatty acid metal salts such as magnesium stearate and calcium stearate; fatty acid amides such as behenamide, stearamide, erucamide, oleamide, methylene bis-stearamide, and ethylene bis-stearamide; polyethylene wax and oxidized polyester wax; glyceryl monostearate, glyceryl monobehenate, and glyceryl monolaurate, etc.; organic acid monoglycerides such as succinic acid saturated fatty acid monoglycerides; sorbitan fatty acid esters such as behenate sorbitan, stearate sorbitan, and laurate sorbitan; polyglycerol fatty acid esters such as diglyceryl stearate, diglyceryl laurate, tetraglyceryl stearate, tetraglyceryl laurate, decaglyceryl stearate, and decaglyceryl laurate; and higher alcohol fatty acid esters such as stearate, etc., but not limited to these. One type of lubricant can be used alone, or two or more types can be used in combination.

[0179] The content of the lubricant (or the total content if multiple lubricants are used) is not particularly limited as long as it imparts slipperiness to the molded article. Preferably, the content of the lubricant is 0.01 parts by weight to 20.00 parts by weight relative to 100 parts by weight of the thermoplastic resin, more preferably 0.05 parts by weight to 10.00 parts by weight, even more preferably 0.10 parts by weight to 10.00 parts by weight, even more preferably 0.20 parts by weight to 5.00 parts by weight, and particularly preferably 0.30 parts by weight to 4.00 parts by weight. When the lubricant content is within the above range, it is possible to prevent the lubricant from seeping from the surface of the molded article and to achieve the corresponding effect of the lubricant.

[0180] <Other Ingredients>

[0181] Without impairing the function of the resulting molded article, this resin composition may contain plasticizers, organic fillers, inorganic fillers, antioxidants, hydrolysis inhibitors, ultraviolet absorbers, dyes, pigments and other colorants, antistatic agents and other components.

[0182] The plasticizer is not particularly limited. Examples of plasticizers include: polyester plasticizers such as polypropylene glycol sebacate; aliphatic diester plasticizers such as di-1-butyl adipate, di-n-butyl sebacate, and di-2-ethylhexyl azelate; glycerol plasticizers such as glyceryl diacetyl monolaurate, glyceryl diacetyl monooctanoate, and glyceryl diacetyl monodecanoate; polycarboxylic acid ester plasticizers such as tri-2-ethylhexyl acetyl citrate and tributyl acetyl citrate; and polyalkylene glycol plasticizers such as polyethylene glycol, polypropylene glycol, poly(ethylene oxide·propylene oxide) block copolymers and / or random copolymers, and polytetramethylene glycol. Plasticizers include: phosphate ester plasticizers such as 2-ethylhexyl diphenyl phosphate and octyl diphenyl phosphate; epoxy 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 castor oil ester, ethyl castor oil ester, isopropyl castor oil ester, butyl castor oil ester, ethylene glycol monocastor oil ester, propylene glycol monocastor oil ester, trimethylolpropane monocastor oil ester, sorbitan monocastor oil ester, castor oil fatty acid polyethylene glycol ester, castor oil ethylene oxide adduct, castor oil polyols, castor oil triols, or castor oil diols. These plasticizers can be used alone or in combination of two or more.

[0183] The organic filler is not particularly limited. Examples of such organic fillers include: fillers made from naturally derived materials such as wood materials (e.g., wood chips, wood flour, sawdust, etc.), rice husks, starch, corn stalks, rice straw, wheat straw, and natural rubber; organic fibers such as plant-based natural fibers, animal-based natural fibers, and synthetic fibers; and fillers made from synthetic resin materials such as polyester, polyacrylic acid, polyamide, nylon, polyethylene, polyolefin, polyvinyl alcohol, polyvinyl chloride, polyurethane, polyacetal, aromatic polyamide, PBO (poly(p-phenylenebenzobisoxazole)), polyphenylene sulfide, cellulose acetate, polybenzoazole, polyarylate, polyvinyl acetate, and synthetic rubber.

[0184] The term "plant-based natural fiber" is not particularly limited. Examples of such plant-based natural fibers include kenaf fiber, abaca fiber, bamboo fiber, jute fiber, hemp fiber, flax fiber, sisal fiber (yucatan sisal fiber), ramie fiber, hemp fiber, cotton fiber, banana fiber, coconut shell fiber, coconut palm fiber, palm fiber, paper mulberry fiber, trifoliate orange fiber, bagasse fiber, etc. Additionally, regenerated fibers such as pulp, cellulose fiber, and rayon, which are processed from plant fibers, can also be mentioned. Examples of animal-based natural fibers include wool, silk, cashmere, and mohair.

[0185] The inorganic filler is not particularly limited. Examples of such inorganic fillers include: silica-based inorganic fillers (e.g., quartz, fumed silica, anhydrous silica, fused silica, crystalline silica, amorphous silica, fillers formed by the condensation of alkoxysilanes, ultrafine random silica, etc.), alumina, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, silicon carbide, glass, silicone rubber, silicone resin, titanium oxide, carbon fiber, mica, graphite, carbon black, ferrite, graphite, diatomaceous earth, kaolin, clay, talc, calcium carbonate, manganese carbonate, magnesium carbonate, barium sulfate, silver powder, etc. These inorganic fillers can also be surface-treated to improve their dispersibility in the resin composition. Furthermore, one type of these inorganic filler can be used alone, or two or more can be used in combination.

[0186] The antioxidant is not particularly limited. Examples of antioxidants include phenolic antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These antioxidants can be used alone or in combination of two or more.

[0187] The hydrolysis inhibitor is not particularly limited. Examples of hydrolysis inhibitors include carbodiimide compounds, epoxy compounds, isocyanate compounds, and oxazoline compounds. These hydrolysis inhibitors can be used alone or in combination of two or more.

[0188] The ultraviolet absorber is not particularly limited. Examples of such ultraviolet absorbers include benzophenone compounds, benzotriazole compounds, triazine compounds, salicylic acid compounds, cyanoacrylate compounds, and nickel complex salt compounds. These ultraviolet absorbers can be used alone or in combination of two or more.

[0189] The pigments, dyes, and other colorants mentioned are not particularly limited. Examples of colorants include: inorganic colorants such as titanium dioxide, calcium carbonate, chromium oxide, cuprous oxide, calcium silicate, iron oxide, carbon black, graphite, titanium yellow, and cobalt blue; soluble azo pigments such as American red, lisol red, and brilliance red; insoluble azo pigments such as dinitro orange and fast yellow; phthalocyanine pigments such as monochlorophthalocyanine blue, polychlorophthalocyanine blue, and polybrominated phthalocyanine green; fused polycyclic pigments such as indigo, perylene red, isoindolinone yellow, and quinacridone red; and dyes such as Oraset yellow. These colorants can be used individually or in combination of two or more.

[0190] The antistatic agent is not particularly limited. Examples of antistatic agents include low-molecular-weight antistatic agents such as fatty acid ester compounds, aliphatic ethanolamine compounds, and aliphatic ethanolamide compounds, as well as high-molecular-weight antistatic agents. These antistatic agents can be used alone or in combination of two or more.

[0191] In addition, this resin composition may also contain: catalyst deactivators (hindered phenolic compounds, thioether compounds, vitamin compounds, triazole compounds, polyamine compounds, hydrazine derivative compounds, phosphorus compounds, etc.), release agents (monadine and its salts, monadine esters, monadine half-esters, stearyl alcohol, stearamide, and polyethylene wax, etc.), anti-staining agents (phosphites, hypophosphites, etc.), silane coupling agents (epoxysilane coupling agents, aminosilane coupling agents, (meth)acryloylsilane coupling agents, isocyanate silane coupling agents, etc.), and flame retardants (red phosphorus, phosphate esters, brominated polystyrene, brominated polyphenylene ether, brominated polycarbonate). Esters, aluminum hydroxide, magnesium hydroxide, melamine and cyanuric acid or their salts, silicon compounds, etc.), conductive agents (carbon black, etc.), lubrication modifiers (graphite, fluororesins, etc.), epoxy compounds (glycidyl ether compounds, glycidyl ester compounds, polymers formed by grafting or copolymerizing glycidyl-based compounds, etc.), acid anhydride compounds (maleic anhydride, succinic anhydride, polymers formed by grafting or copolymerizing acid anhydrides, etc.), carbodiimide compounds (N,N'-bis(2,6-diisopropylphenylcarbodiimide), 2,6,2',6'-tetraisopropyldiphenylcarbodiimide, polycarbodiimide, etc.), etc.

[0192] The content of the other components described above is not particularly limited as long as it can achieve the effect of one embodiment of the present invention, and can be appropriately set by those skilled in the art.

[0193] <Method for manufacturing thermoplastic resin compositions>

[0194] This resin composition can be manufactured by known methods. Specifically, methods such as using an extruder, kneader, Banbury mixer, or mixing roller to melt-blend a thermoplastic resin, crosslinked resin particles, and, as optional components, a nucleating agent, lubricant, and other ingredients. When melt-blending, it is preferable to take care to avoid the decrease in molecular weight due to thermal decomposition during mixing. Alternatively, the thermoplastic resin composition can be manufactured by first dissolving all raw materials (components) in a soluble solvent and then removing the solvent.

[0195] When manufacturing thermoplastic resin compositions by melt mixing, each component can be fed separately into an extruder or the like, or a mixture obtained by premixing the components can be fed into an extruder or the like. For example, an aqueous dispersion of thermoplastic resin can be mixed with an aqueous dispersion of crosslinked resin particles, and then the resulting mixture can be dried in a dryer to obtain a mixed powder, which can then be fed into an extruder or the like.

[0196] When melt-blending is performed using an extruder, the resulting thermoplastic resin composition can also be extruded from the extruder into strips and cut, thereby processing the thermoplastic resin composition into granular shapes such as rods, cylinders, elliptical cylinders, spheres, cubes, and histograms.

[0197] The resin temperature during melt mixing depends on the melting point and melt viscosity of the resin used, and therefore cannot be generalized. From the viewpoint of avoiding thermal decomposition of the thermoplastic resin while uniformly dispersing the crosslinked resin particles in the thermoplastic resin, the resin temperature is preferably 140°C to 250°C, more preferably 150°C to 230°C, and even more preferably 160°C to 210°C.

[0198] <Manufacturing Method of Molded Components>

[0199] In one embodiment of the present invention, a molded article formed from the resin composition is provided. The molding method for the thermoplastic resin composition is not particularly limited, and commonly used molding methods can be used. Specifically, examples of molding methods include blow molding, extrusion blow molding, injection blow molding, extrusion molding, calendering, vacuum forming, and injection molding. The molded article formed from the thermoplastic resin composition may also be referred to as a molded article containing a thermoplastic resin composition.

[0200] By using this resin composition to carry out the above-described molding method, molded articles with excellent impact resistance can be provided with good manufacturability. Specifically, film-molded articles, sheet-molded articles, blow-molded articles, extruded articles, vacuum-molded articles, or injection-molded articles can be manufactured. Furthermore, in this specification, "film-molded article" refers to a thin film-like molded article with a thickness of less than 0.25 mm, according to JIS 20108: 2012. In this specification, "sheet-molded article" refers to a thin sheet-like molded article with a thickness of 0.25 mm or more, according to JIS 20108: 2012.

[0201] Molded bodies containing this resin composition are suitable for agriculture, fisheries, forestry, horticulture, medicine, hygiene products, food industry, clothing, non-clothing materials, packaging, automobiles, building materials, and other fields.

[0202] [3. Modifiers for thermoplastic resins]

[0203] One embodiment of the present invention provides a modifier for thermoplastic resins comprising cross-linked resin particles, said cross-linked resin particles comprising a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more. By incorporating the modifier for thermoplastic resins according to one embodiment of the present invention into a thermoplastic resin, a resin composition is provided that can be used to provide molded articles with excellent impact resistance.

[0204] Regarding various methods of using modifiers for thermoplastic resins, the description in the aforementioned section [1. Crosslinked resin particles] may be appropriately cited.

[0205] Another embodiment of the present invention may be as follows.

[0206] [1] A cross-linked resin particle comprising a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more.

[0207] [2] The cross-linked resin particles according to [1], wherein the cross-linked resin particles do not include: cross-linked resin particles containing more than 90% by weight of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as the biodegradable resin (A).

[0208] [3] According to the cross-linked resin particles of [1] or [2], wherein the biodegradable resin (A) is selected from one or more of (i) poly(3-hydroxybutyrate-co-4-hydroxybutyrate), (ii) poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), (iii) polycaprolactone, (iv) an aliphatic polyester comprising a structure formed by the condensation of an aliphatic diol and an aliphatic dicarboxylic acid, and (v) an aliphatic aromatic polyester.

[0209] [4] The cross-linked resin particles according to any one of [1] to [3], wherein the median particle size of the cross-linked resin particles is 0.10 μm to 10.00 μm.

[0210] [5] The cross-linked resin particles according to any one of [1] to [4], wherein the cross-linked resin particles are formed by cross-linking with peroxide.

[0211] [6] The cross-linked resin particles according to [5], wherein the cross-linked resin particles are formed by cross-linking in the presence of the peroxide and the polyfunctional compound.

[0212] [7] The cross-linked resin particles according to any one of [1] to [6], wherein the cross-linked resin particles are not foamed.

[0213] [8] A thermoplastic resin composition comprising a thermoplastic resin and cross-linked resin particles as described in any one of [1] to [7].

[0214] [9] The thermoplastic resin composition according to [8], wherein the thermoplastic resin comprises a biodegradable resin (B).

[0215]

[10] The thermoplastic resin composition according to [9], wherein the biodegradable resin (B) comprises a polyester resin.

[0216]

[11] The thermoplastic resin composition according to any one of [8] to

[10] further comprises a crystallizing nucleating agent and / or a lubricant.

[0217]

[12] A molded body formed from any one of the thermoplastic resin compositions described in [8] to

[11] .

[0218]

[13] The molded body according to

[12] , wherein the molded body is a film molded body, a sheet molded body, a blow molded body, an extruded molded body, a vacuum molded body or an injection molded body.

[0219]

[14] A thermoplastic resin modifier comprising crosslinked resin particles, the crosslinked resin particles comprising a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more.

[0220]

[15] The thermoplastic resin modifier according to

[14] , wherein the crosslinked resin particles do not include: crosslinked resin particles containing more than 90% by weight of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as the biodegradable resin (A).

[0221] [Example]

[0222] The following examples illustrate one embodiment of the invention in more detail, but the invention is by no means limited to these examples.

[0223] [Measurement conditions]

[0224] (Median particle size (D50))

[0225] The median particle size of cross-linked resin particles was determined using an aqueous dispersion of the particles as a sample. A Microtrac MT3300 EX II manufactured by Nikkiso Corporation was used as the measuring apparatus. More specifically, the particle size at which the large diameter side and the small diameter side of the measured cumulative particle size distribution are equal in amount (50%) was defined as the "median particle size (D50)".

[0226] (Gel fraction)

[0227] The dried cross-linked resin particles were added to chloroform at a concentration of 0.7% by weight and kept at 60°C for 30 minutes to obtain a chloroform solution. The solution was then allowed to stand at room temperature for 3 hours and filtered through a membrane filter with a pore size of 0.45 μm. The container and the filter were thoroughly washed multiple times with chloroform while filtration to prevent loss of gel residue on the filter. The weight of the solution, including the filter, was measured, and the gel fraction was calculated using the following formula.

[0228] Formula: Gel fraction (%) = {(Weight of filter including dried gel - Weight of filter alone) / Weight of cross-linked resin particles for measurement} × 100.

[0229] (Solubility in chloroform)

[0230] The dried cross-linked resin particles were added to chloroform at a concentration of 0.7% by weight, and the solubility was visually confirmed. If the dried particles did not dissolve but swelled in chloroform and remained suspended, they were considered insoluble, and this was used as an indicator of gelation.

[0231] (glass transition temperature (Tg))

[0232] The temperature determined by the following method (differential scanning calorimetry (DSC)) is defined as the glass transition temperature of the resin (uncrosslinked resin particles). (1) 2-3 mg of resin is packed into an aluminum dish; (2) The aluminum dish is provided to a differential scanning calorimeter, and the temperature of the analyzer is increased from -80°C to 180°C at a rate of 10°C / min under a nitrogen flow to completely melt the resin; (3) Then, the temperature of the analyzer is decreased from 180°C to -80°C at a rate of 10°C / min; (4) The temperature of the analyzer is increased from -80°C to 180°C again at a rate of 10°C / min; (5) According to the DSC curve obtained in (4), the intermediate temperature between the temperature at which the baseline shifts (changes) begins and the temperature at the end is taken as the glass transition temperature (Tg) of the resin (uncrosslinked resin particles).

[0233] (Tensive fracture ductility)

[0234] A 200 μm thick molded body (film molded body) prepared according to the method described later was used as a sample. The sample was cured at 23°C and 50%RH for 7 days. Then, the tensile ductility at 23°C was determined using a tensile testing machine (Shimadzu Corporation EZ-LX1kN) based on the method of JIS K 7127 at a test speed of 100 mm / min.

[0235] (Tensile impact strength)

[0236] The 500 μm thick molded body (sheet molded body) prepared by the method described later was cured for 7 days at 23°C and 50% RH, and then punched into the shape specified in JIS K71603, which was used as the test piece. Tensile impact tests were carried out on the test piece using the method based on JIS K7160A.

[0237] [Manufacturing of cross-linked resin particles]

[0238] (Raw material for cross-linked resin particles)

[0239] <Uncrosslinked resin particles>

[0240] The corresponding resin particles of the following biodegradable resins were used as uncrosslinked resin particles. The Tg of each biodegradable resin is shown in Table 1.

[0241] • PHA-1: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), with repeating unit composition of (3-hydroxybutyrate) / (3-hydroxyhexanoate) = 72 / 28 (mol / mol), and a weight-average molecular weight (Mw) of 500,000 to 1,500,000.

[0242] • PHA-2: Poly(3-hydroxybutyrate-co-4-hydroxybutyrate), with repeating unit composition of (3-hydroxybutyrate) / (4-hydroxybutyrate) = 65 / 35 (mol / mol), and a weight-average molecular weight (Mw) of 400,000 to 1,500,000.

[0243] • PHA-3: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), with a weight-average molecular weight (Mw) of 500,000 to 1,500,000.

[0244] • PHA-4: Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), with a weight-average molecular weight (Mw) of 500,000 to 1,500,000.

[0245] • PBAT: Ecoflex F blend C1200 manufactured by BASF (registered trademark) • PBSA: FD92 manufactured by Mitsubishi Chemical Corporation

[0246] • PCL: Capa 6800 manufactured by Ingevity

[0247] • PHA / PCL: A mixture of 50% by weight of the aforementioned PHA-1 and 50% by weight of the aforementioned PCL (total 100% by weight)

[0248] •PBS: "Bionolle (registered trademark)" manufactured by Showa Denko Co., Ltd.

[0249] <Peroxides>

[0250] • Di-sec-butyl percarbonate: "Luperox 225" manufactured by Arkema Corporation, with a 1-hour half-life temperature of 69°C.

[0251] <Multifunctional Compounds>

[0252] Triallyl isocyanurate

[0253] (Method for manufacturing cross-linked resin particles)

[0254] (Examples 1-7)

[0255] The cross-linked resin particles of Examples 1 to 7 were manufactured according to the steps described below.

[0256] The resins listed in Table 1 were completely dissolved in chloroform at a concentration of 10% to obtain raw material 1. Bacillus subtilis lipopeptide surfactantin (manufactured by Kaneka Corporation) and glycerol were mixed at a ratio of 6 / 94 by weight and stirred for 5-10 minutes to obtain raw material 2. Raw material 1 and raw material 2 were weighed to achieve a ratio of 86 / 14 by weight. While stirring raw material 2, raw material 1 was slowly added dropwise to raw material 2, and after all raw material 1 had been added, the mixture was stirred for another 30 minutes. Then, 100% by weight of deionized water (relative to the total 100% by weight of raw material 1 and raw material 2) was added to the mixture to obtain a dispersion of resin particles. Afterwards, the dispersion was stirred at 65°C for approximately 30 minutes to remove residual chloroform, thereby obtaining an aqueous dispersion of uncrosslinked resin particles.

[0257] An aqueous dispersion was prepared in a glass container equipped with a stirrer, baffle, nitrogen inlet, nitrogen outlet, and thermometer. The dispersion consisted of 100 parts by weight of an aqueous solution containing uncrosslinked resin particles dispersed in water, 200 parts by weight of deionized water, the amounts of peroxide listed in Table 1, 2 parts by weight of sodium dioctyl sulfosuccinate, and the amounts of a multifunctional compound listed in Table 1. The resulting aqueous dispersion was then stirred at room temperature while the glass container was purged with nitrogen.

[0258] The contents (aqueous dispersion) in the glass container were then stirred at room temperature for 1 hour. This process allowed the peroxide and multifunctional compounds to penetrate into the uncrosslinked resin particles. The aqueous dispersion was then heated to the temperature listed in the "Temperature" column of "Crosslinking Conditions" in Table 1. Once this temperature was reached, the aqueous dispersion was maintained at that temperature for the time listed in the "Time" column of "Crosslinking Conditions" in Table 1. This process allowed the crosslinking agent to react, resulting in an aqueous dispersion of crosslinked resin particles in water.

[0259] After adjusting the pH of the aqueous dispersion, it was dried in an oven. The resulting solid was washed several times with deionized water to remove residual glycerol from the crosslinked resin particles. The washed crosslinked resin particles were then dried again in an oven to obtain solidified crosslinked resin particles. The resulting crosslinked resin particles can also be referred to as a modifier for thermoplastic resins.

[0260] (Examples 14 and 15)

[0261] The crosslinked resin particles of Examples 14 and 15 were manufactured according to the steps described below. In a glass container equipped with a stirrer, baffle, nitrogen inlet, nitrogen outlet, and thermometer, an aqueous dispersion (100 parts by weight of solids) of uncrosslinked resin particles dispersed in water, 200 parts by weight of deionized water, the amount of peroxide listed in Table 1, 1 part by weight of sodium dioctyl sulfosuccinate, and the amount of multifunctional compound listed in Table 1 were added to prepare an aqueous dispersion. The resulting aqueous dispersion was then stirred at room temperature (25 ± 5 °C) while the glass container was purged with nitrogen.

[0262] The contents (aqueous dispersion) in the glass container were then stirred at room temperature for 1 hour. This process allowed the peroxide and multifunctional compounds to penetrate into the uncrosslinked resin particles. The aqueous dispersion was then heated to the temperature listed in the "Temperature" column of "Crosslinking Conditions" in Table 1. Once this temperature was reached, the aqueous dispersion was maintained at that temperature for the time listed in the "Time" column of "Crosslinking Conditions" in Table 1. This process allowed the crosslinking agent to react, resulting in an aqueous dispersion of crosslinked resin particles in water.

[0263] After adjusting the pH of the aqueous dispersion, the dispersion was dried in an oven to obtain solidified cross-linked resin particles. The resulting cross-linked resin particles can also be referred to as a modifier for thermoplastic resins.

[0264] The median particle size, gel fraction, and solubility in chloroform of the crosslinked resin particles obtained in each embodiment were determined according to the aforementioned method. The results are shown in Table 1.

[0265] [Preparation of thermoplastic resin compositions]

[0266] (Raw materials for thermoplastic resin compositions)

[0267] <Thermoplastic Resins>

[0268] • P3HB3HH (Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)): A biodegradable polymer PHBH (registered trademark) manufactured by Kaneka Corporation. Its repeating unit composition is (3-hydroxybutyrate) / (3-hydroxyhexanoate) = 94.4 / 5.6 (mol / mol), with a weight-average molecular weight (Mw) of 530,000 and a Tg of 3°C.

[0269] Cross-linked resin particles

[0270] Crosslinked resin particles prepared in Examples 1-5, 7, 14 and 15

[0271] <Crystallization nucleating agent>

[0272] • Pentaerythritol: NOILIZER P manufactured by Nippon Synthetic Chemical Industry Co., Ltd.

[0273] Lubricant

[0274] • Behenamide: BNT22H manufactured by Nippon Seika Co., Ltd.

[0275] (Method for manufacturing thermoplastic resin composition)

[0276] In each embodiment, the thermoplastic resin, crosslinking resin particles, crystallizing nucleating agent, and lubricant listed in Table 2 were mixed in the amounts listed in Table 2 to obtain a mixture. The resulting mixture was melt-mixed for 180 seconds using a twin-screw small mixer (DSM Xplore MC5) with the barrel temperature heated to 175 degrees Celsius and the screw speed at 100 rpm to obtain a melt-mixed compound. The resulting melt-mixed compound was dried in a dryer at 80 degrees Celsius for 4 hours to sufficiently reduce the moisture content, thereby obtaining the thermoplastic resin compositions of Comparative Example 1 and Examples 8-13, 16, and 17. The thermoplastic resin compositions of Comparative Example 1 and each embodiment were pressed into molded bodies (film molded bodies and sheet molded bodies) at 165 degrees Celsius to a specified thickness, thereby obtaining molded bodies (film molded bodies and sheet molded bodies).

[0277] The tensile ductility at break of the molded articles of Comparative Example 1 and each embodiment was measured according to the aforementioned method. Furthermore, the tensile impact strength of the molded articles of Comparative Example 1, Examples 11, 13, 16, and 17 was measured according to the aforementioned method. The results are shown in Table 2.

[0278] As can be seen from Table 2, the molded articles of the examples with added crosslinked resin particles exhibit better tensile ductility and tensile impact strength compared to the molded articles of the comparative examples without added crosslinked resin particles.

[0279] [Table 1]

[0280]

[0281] [Table 2]

[0282]

[0283] [Industry availability]

[0284] According to one embodiment of the present invention, cross-linked resin particles with excellent biodegradability, impact resistance, and tensile properties can be provided. Therefore, one embodiment of the present invention can be well applied to thermoplastic resin modifiers, spacers, anti-blocking agents, matting agents, etc.

Claims

1. A cross-linked resin particle, It contains a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of more than 50%.

2. The cross-linked resin particles according to claim 1, wherein, The cross-linked resin particles do not include: cross-linked resin particles containing more than 90% by weight of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as the biodegradable resin (A).

3. The cross-linked resin particles according to claim 1, wherein, The biodegradable resin (A) is selected from one or more of the following: (i) poly(3-hydroxybutyrate-co-4-hydroxybutyrate), (ii) poly(3-hydroxybutyrate-co-3-hydroxyhexanoate-co-3-hydroxyoctanoate), (iii) polycaprolactone, (iv) aliphatic polyesters comprising a structure formed by the condensation polymerization of aliphatic diols and aliphatic dicarboxylic acids, and (v) aliphatic aromatic polyesters.

4. The cross-linked resin particles according to claim 1, wherein, The median particle size of the cross-linked resin particles is 0.10 μm to 10.00 μm.

5. The cross-linked resin particles according to claim 1, wherein, The cross-linked resin particles are formed by cross-linking with peroxide.

6. The cross-linked resin particles according to claim 5, wherein, The cross-linked resin particles are formed by cross-linking in the presence of the peroxide and the polyfunctional compound.

7. The cross-linked resin particles according to claim 1, wherein, The cross-linked resin particles were not foamed.

8. A thermoplastic resin composition comprising a thermoplastic resin and crosslinked resin particles according to any one of claims 1 to 7.

9. The thermoplastic resin composition according to claim 8, wherein, The thermoplastic resin includes a biodegradable resin (B).

10. The thermoplastic resin composition according to claim 9, wherein, The biodegradable resin (B) comprises a polyester resin.

11. The thermoplastic resin composition according to claim 8, further comprising a crystallizing nucleating agent and / or a lubricant.

12. A molded body formed from the thermoplastic resin composition of claim 8.

13. The molded article according to claim 12, wherein, The molded body is a film molded body, sheet molded body, blow molded body, extruded molded body, vacuum molded body or injection molded body.

14. A modifier for thermoplastic resins, It contains cross-linked resin particles, The cross-linked resin particles contain a biodegradable resin (A) with a glass transition temperature below 0°C and a gel fraction of 50% or more.

15. The thermoplastic resin modifier according to claim 14, wherein, The cross-linked resin particles do not include: cross-linked resin particles containing more than 90% by weight of poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) as the biodegradable resin (A).

Images