Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
  • C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F283/00—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G
  • C08F283/02—Macromolecular compounds obtained by polymerising monomers on to polymers provided for in subclass C08G on to polycarbonates or saturated polyesters
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G63/00—Macromolecular compounds obtained by reactions forming a carboxylic ester link in the main chain of the macromolecule
  • C08G63/91—Polymers modified by chemical after-treatment
  • C08G63/912—Polymers modified by chemical after-treatment derived from hydroxycarboxylic acids
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L51/00—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers
  • C08L51/08—Compositions of graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers grafted on to macromolecular compounds obtained otherwise than by reactions only involving unsaturated carbon-to-carbon bonds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/22—Mixtures comprising a continuous polymer matrix in which are dispersed crosslinked particles of another polymer

Definitions

• the present invention relates to a thermoplastic resin composition containing polylactic acid.
• Polylactic acid is a biodegradable polyester resin that can be produced by polymerizing lactic acid obtained through microbial fermentation of renewable plant-derived raw materials such as starch.
• the use of polylactic acid has been attracting attention in recent years from the perspective of building a recycling-oriented society and curbing climate change caused by increasing carbon dioxide emissions.
• Patent Document 1 describes a technique for improving the impact resistance of polylactic acid by blending it with an aliphatic polyester such as polycaprolactone or a condensation product of butanediol and succinic acid.
• Patent Document 1 makes it possible to improve the impact resistance of polylactic acid while ensuring the biodegradability of the resin composition as a whole, but this is still not sufficient and there is room for further improvement.
• the present invention aims to provide a thermoplastic resin composition in which the impact strength of polylactic acid is improved.
• the present invention relates to a thermoplastic resin composition that contains 40 to 99 parts by weight of polylactic acid (A) and 1 to 60 parts by weight of crosslinked resin particles (B) that contain a polyhydroxyalkanoate resin and have a gel fraction of 50% or more (provided that the total amount of (A) and (B) is 100 parts by weight).
• thermoplastic resin composition having improved impact strength of polylactic acid.
• the thermoplastic resin composition according to the present invention contains polylactic acid and crosslinked resin particles constituted by a polyhydroxyalkanoate-based resin, and is therefore advantageous in terms of biodegradability.
• the crosslinked resin particles can be utilized as a modifier or impact resistance improver for polylactic acid.
• a thermoplastic resin composition having good tensile elongation in addition to impact strength can be provided.
• thermoplastic resin composition contains at least polylactic acid (A) and crosslinked resin particles (B) containing a polyhydroxyalkanoate resin and having a gel fraction of 50% or more.
• the impact strength of the polylactic acid (A) is improved, and the composition exhibits good impact resistance.
• the crosslinked resin particles (B) will be described.
• the crosslinked resin particles (B) are particles composed of a polyhydroxyalkanoate resin as a main resin component.
• PHA polyhydroxyalkanoate resin
• PHA is a general term for polymers having hydroxyalkanoic acid as a monomer unit, and is generally biodegradable.
• PHA is an aliphatic polyester, preferably a polyester not containing an aromatic ring.
• PHA is not particularly limited, but examples include polyglycolic acid, poly(3-hydroxyalkanoate) resins, poly(4-hydroxyalkanoate) resins, etc. Only one type of PHA may be used, or two or more types may be used in combination. Of these, poly(3-hydroxyalkanoate) resins are preferred. In the following, poly(3-hydroxyalkanoate) resins may be abbreviated as "P3HA.”
• the P3HA is a polyhydroxyalkanoate containing, as an essential repeating unit, a 3-hydroxyalkanoic acid repeating unit represented by the formula: [-CHR-CH 2 -CO-O-] (wherein R is an alkyl group represented by C n H 2n+1 , and n is an integer of 1 to 15).
• the P3HA preferably contains 50 mol % or more, and more preferably 70 mol % or more, of the 3-hydroxyalkanoic acid repeating units out of all monomer repeating units (100 mol %).
• P3HA is not particularly limited, and may be a homopolymer containing the repeating unit described above, or a copolymer containing the repeating unit described above.
• the copolymer include copolymers of 3-hydroxybutanoic acid (hereinafter sometimes referred to as "3HB") and one or more monomers selected from the group consisting of 3-hydroxypropionic acid, 3-hydroxypentanoic acid, 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.
• 3HB 3-hydroxybutanoic acid
• copolymer examples include copolymers of 3HB and one or more monomers selected from the group consisting of 4-hydroxybutanoic acid, 4-hydroxypentanoic acid, 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.
• monomers selected from the group consisting of 4-hydroxybutanoic acid, 4-hydroxypentanoic acid, 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-hydroxyt
• copolymer examples include, but are not limited to, poly(3-hydroxybutyrate) (abbreviation: P3HB), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (abbreviation: P3HB3HH), poly(3-hydroxybutyrate-co-4-hydroxybutyrate) (abbreviation: P3HB4HB), and the like.
• P3HA poly(3-hydroxybutyrate)
• P3HB3HH poly(3-hydroxybutyrate-co-3-hydroxyhexanoate)
• P3HB4HB poly(3-hydroxybutyrate-co-4-hydroxybutyrate)
• poly(X-co-Y) refers to a copolymer containing an X repeating unit and a Y repeating unit, and is obtained by copolymerizing a monomer from which the X repeating unit is derived and a monomer from which the Y repeating unit is derived.
• a small amount (less than 1 mol%) of a monomer may be copolymerized. If this does not significantly affect the physical properties of the resulting P3HA, the monomer is considered to be not copolymerized, and the product will be called by a name that does not include that monomer.
• P3HA can be produced by microorganisms. Such microbially produced P3HA is usually P3HA composed only of D-form (R-form) hydroxyalkanoic acid repeating units. Among microbially produced P3HA, P3HB, P3HB3HH, and P3HB4HB are preferred, with P3HB3HH and P3HB4HB being more preferred, in terms of ease of industrial production.
• the composition ratio of the 3HB repeating units in all monomer repeating units is preferably 60 to 99 mol%, more preferably 61 to 97 mol%, and even more preferably 62 to 95 mol%, from the viewpoint of the balance between flexibility and strength.
• the composition ratio of the 3HB repeating units is 60 mol% or more, the crosslinked resin particles (B) are easy to handle.
• the composition ratio of the 3HB repeating units is 99 mol% or less, the flexibility of the crosslinked resin particles (B) tends to be easily ensured.
• the monomer composition ratio of P3HA can be measured by gas chromatography or the like (see, for example, International Publication No. 2014/020838). Two or more types of P3HA having different composition ratios of the 3HB repeating units may be used in combination.
• the microorganisms that produce P3HA are not particularly limited as long as they have the ability to produce P3HA.
• the first P3HB-producing bacterium was Bacillus megaterium, discovered in 1925, and other natural microorganisms are known, including Cupriavidus necator (formerly classified as Alcaligenes eutrophus, Ralstonia eutropha) and Alcaligenes latus. In these microorganisms, P3HB accumulates within the bacterial cells.
• Aeromonas caviae which produces P3HB3HH
• Alcaligenes eutrophus which produces poly(3-hydroxybutyrate-co-4-hydroxybutyrate)
• Aeromonas caviae which produces P3HB3HH
• Alcaligenes eutrophus which produces poly(3-hydroxybutyrate-co-4-hydroxybutyrate)
• Microorganisms such as these that have been cultured under appropriate conditions to accumulate P3HA within the cells are used.
• genetically modified microorganisms into which various P3HA synthesis-related genes have been introduced can be used depending on the P3HA to be produced, and culture conditions, including the type of substrate, can be optimized.
• the molecular weight of the PHA is not particularly limited, but the weight average molecular weight is preferably 50,000 to 3,000,000, more preferably 100,000 to 2,000,000, and more preferably 150,000 to 1,500,000.
• the weight average molecular weight is a value measured before the PHA is subjected to a crosslinking treatment.
• the weight average molecular weight can be measured using gel permeation chromatography (GPC) (Shimadzu Corporation's "High Performance Liquid Chromatograph 20A System"), a polystyrene gel (Showa Denko KK's "K-G 4A", “K-806M”, etc.) as a column, chloroform as the mobile phase, and the molecular weight calculated as polystyrene.
• GPC gel permeation chromatography
• a polystyrene gel Showa Denko KK's "K-G 4A", “K-806M”, etc.
• chloroform as the mobile phase
• a calibration curve can be created using polystyrene with weight average molecular weights of 31,400, 197,000, 668,000, and 1,920,000.
• the column used in the GPC can be a column appropriate for measuring the molecular weight.
• the crosslinked resin particles (B) have a crosslinked structure in which molecular chains of PHA are bonded to each other. Since the crosslinked resin particles (B) have a certain amount or more of such crosslinked structure, they show a high gel fraction, specifically, a gel fraction of 50% or more. By showing such a high gel fraction, the effect of improving the impact strength of the polylactic acid (A) can be enhanced.
• the gel fraction value is preferably 60% or more, more preferably 70% or more, even more preferably 75% or more, and particularly preferably 80% or more. It may also be 85% or more, or 90% or more. There is no particular upper limit to the gel fraction, and it may be 100% or less. However, from the viewpoint of production efficiency of the crosslinked resin particles (B) and improvement of impact strength, it is preferably 99.5% or less, more preferably 99% or less. It may also be 98% or less, 97% or less, or 96% or less.
• the gel fraction is a value measured as follows. A dried product of the crosslinked resin particles (B) is added to chloroform so as to have a concentration of 0.7% by weight, and dissolved at 60° C. for 30 minutes to obtain a chloroform solution. After that, the solution is left to stand at room temperature for 3 hours, and then the chloroform solution is filtered through a membrane filter having a pore size of 0.45 ⁇ m. The gel remaining on the filter is dried, and the weight of the gel and the filter are measured, and the gel fraction is calculated according to the following formula.
• Formula: Gel fraction (weight of filter including dry gel ⁇ weight of filter only)/weight of crosslinked resin particles used in measurement ⁇ 100(%)
• the crosslinked resin particles (B) preferably have a volume average particle diameter in the range of 0.1 ⁇ m or more and 10 ⁇ m or less. By having such a particle diameter, the impact strength of the polylactic acid (A) can be further improved. From the viewpoint of practical use, the lower limit of the particle diameter is preferably 0.1 ⁇ m or more, more preferably 0.3 ⁇ m or more, and even more preferably 0.5 ⁇ m or more. In addition, from the viewpoint of productivity (production of PHA, crosslinking treatment, etc.), the upper limit of the particle diameter is preferably 8 ⁇ m or less, more preferably 5 ⁇ m or less. However, by melt-kneading the crosslinked resin particles (B) with the polylactic acid (A), the original shape of the crosslinked resin particles (B) may collapse, and the volume average particle diameter may decrease.
• the volume average particle diameter is a value measured when the crosslinked resin particles (B) are dispersed in an aqueous solvent.
• a general-purpose measuring device can be used as the measuring device, and one example of such a device is the Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd.
• the crosslinking type of the crosslinked resin particles (B) is not particularly limited, but it is preferable that the crosslinking is performed using a peroxide.
• a peroxide When a peroxide is used, radicals generated by decomposition of the peroxide act on the PHA molecules to directly bond the molecular chains of the PHA to each other, thereby forming the crosslinked structure.
• the peroxide may be an organic peroxide or an inorganic peroxide.
• Organic peroxides are preferred because they can increase the gel fraction more efficiently.
• organic peroxide it is preferable to use at least one selected from the group consisting of diacyl peroxides, alkyl peroxy esters, dialkyl peroxides, hydroperoxides, peroxyketals, peroxycarbonates, and peroxydicarbonates, taking into consideration the heating temperature and time during the crosslinking treatment.
• organic peroxides include butyl peroxy neododecanoate, octanoyl peroxide, dilauroyl peroxide, succinic peroxide, a mixture of toluoyl peroxide and benzoyl peroxide, benzoyl peroxide, bis(butylperoxy)trimethylcyclohexane, butyl peroxy laurate, dimethyl di(benzoylperoxy)hexane, bis(butylperoxy)methylcyclohexane, bis(butylperoxy)cyclohexane, butyl peroxybenzoate, butyl bis(butylperoxy)valerate, dicumyl peroxide, di-t-hexyl peroxide, and t-butylperoxy 2-ethylhexanoate.
• t-butyl peroxyisobutyrate t-butyl peroxypivalate, t-hexyl peroxypivalate, t-butyl peroxymethyl monocarbonate, t-pentyl peroxymethyl monocarbonate, t-hexyl peroxymethyl monocarbonate, t-heptyl peroxymethyl monocarbonate, t-octyl peroxymethyl monocarbonate, 1,1,3,3-tetramethylbutyl peroxymethyl monocarbonate, t-butyl peroxyethyl monocarbonate, t-pentyl peroxyethyl monocarbonate, t-hexyl peroxyethyl monocarbonate, t-heptyl peroxyethyl monocarbonate, t-octyl peroxyethyl monocarbonate, 1, 1,3,3-tetramethylbutylperoxyethyl monocarbonate, t-butylperoxy n-propyl monocarbonate,
• t-butylperoxyisopropyl monocarbonate t-pentylperoxyisopropyl monocarbonate, t-hexylperoxyisopropyl monocarbonate, t-butylperoxy2-ethylhexyl monocarbonate, t-pentylperoxy2-ethylhexyl monocarbonate, t-hexylperoxy2-ethylhexyl monocarbonate, t-amylperoxyisopropyl monocarbonate, di-t-hexyl peroxide, t-butylperoxy2-ethyl Hexanoate, t-butylperoxyisobutyrate, t-hexylperoxy2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy2-ethylhexanoate, t-butylperoxypivalate, t-hexylperoxypivalate, t-hex
• the peroxide is preferably a compound having a one-hour half-life temperature of 200°C or less, more preferably 170°C or less, and even more preferably 140°C or less, so that the heating temperature during the crosslinking treatment can be set low.
• the lower limit may be 50°C or more, 60°C or more, or 70°C or more.
• Particularly preferred organic peroxides exhibiting such a one-hour half-life temperature are t-butylperoxyisopropylmonocarbonate, t-butylperoxy2-ethylhexylmonocarbonate, di-sec-butylperoxydicarbonate, t-butylperoxy2-ethylhexanoate, t-butylperoxyisobutyrate, t-hexylperoxy2-ethylhexanoate, 1,1,3,3-tetramethylbutylperoxy2-ethylhexanoate, t-butylperoxypivalate, t-hexylperoxypivalate, t-butylperoxyneodecanoate, t-hexylperoxyneodecanoate, and 1,1,3,3-tetramethylbutylperoxyneodecanoate.
• examples of the inorganic peroxide include hydrogen peroxide, potassium peroxide, calcium peroxide, sodium peroxide, magnesium peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate, taking into consideration the heating temperature and time during the crosslinking treatment.
• hydrogen peroxide, potassium persulfate, sodium persulfate, and ammonium persulfate are preferred in that they are easy to handle and have decomposition temperatures suitable for the heating temperature during the crosslinking treatment.
• the inorganic peroxide may be used alone or in combination of two or more types. Also, an organic peroxide and an inorganic peroxide may be used in combination.
• the crosslinked structure in the crosslinked resin particles (B) may be introduced using only a peroxide, or may be introduced using both a peroxide and a polyfunctional compound, since the latter method makes it possible to increase the gel fraction of the crosslinked resin particles (B) with a smaller amount of peroxide.
• the polyfunctional compound refers to a compound having two or more functional groups in one molecule that can crosslink PHA.
• a compound that is reactive with radicals generated from a peroxide is preferred, and a compound having two or more radical reactive groups in one molecule is particularly preferred.
• the radical reactive group is preferably at least one selected from the group consisting of a vinyl group, an allyl group, an acryloyl group, or a methacryloyl group.
• Such polyfunctional compounds are not particularly limited, but examples thereof include allyl (meth)acrylate; allyl alkyl (meth)acrylates; allyloxy alkyl (meth)acrylates; polyfunctional (meth)acrylates having two or more (meth)acrylic groups, such as ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, and pentaerythritol (meth)acrylate; divinylbenzene, diallyl phthalate, triallyl cyanurate, triallyl isocyanurate, and divinylbenzene. Allyl methacrylate, triallyl isocyanurate, butanediol di(meth)acrylate, and divinylbenzene are preferred, and ally
• the resulting crosslinked resin particles (B) may usually contain a structure derived from the polyfunctional compound.
• the molecular chains of the PHA are bonded to each other via the structure derived from the polyfunctional compound.
• the crosslinked resin particles (B) may be composed only of PHA having a crosslinked structure, or may further contain components other than PHA having a crosslinked structure.
• components other than PHA having a crosslinked structure include resins other than PHA, antioxidants, hydrolysis inhibitors, antiblocking agents, crystal nucleating agents, lubricants, ultraviolet absorbers, etc.
• the proportion of PHA in the crosslinked resin particles (B) is not particularly limited, but may be 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more, even more preferably 90% by weight or more, and particularly preferably 95% by weight or more. It may also be 99% by weight or more. There is no particular upper limit, and it may be 100% by weight or less.
• resins other than PHA include polycaprolactone (PCL), polylactic acid (PLA), aliphatic polyesters consisting of a structure in which aliphatic diols and aliphatic dicarboxylic acids are polycondensed, and aliphatic aromatic polyesters having both aliphatic and aromatic compounds as monomers.
• PCL polycaprolactone
• PLA polylactic acid
• aliphatic polyesters consisting of a structure in which aliphatic diols and aliphatic dicarboxylic acids are polycondensed
• aliphatic aromatic polyesters having both aliphatic and aromatic compounds as monomers examples of the former include polyethylene succinate, polybutylene succinate (PBS), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene succinate adipate (PBSA), polyethylene sebacate, and polybutylene sebacate.
• PCL polycaprolactone
• PLA
• Examples of the latter include poly(butylene adipate-co-butylene terephthalate) (PBAT), poly(butylene sebacate-co-butylene terephthalate), poly(butylene azelate-co-butylene terephthalate), poly(butylene succinate-co-butylene terephthalate) (PBST), etc.
• PBAT poly(butylene adipate-co-butylene terephthalate)
• PBST poly(butylene sebacate-co-butylene terephthalate)
• PBST poly(butylene succinate-co-butylene terephthalate)
• the other resins may be used alone or in combination of two or more.
• the crosslinked resin particles (B) are different from the expanded resin particles disclosed in WO 2007/049694 and WO 2019/146555, and are preferably non-expanded, i.e., do not substantially contain air bubbles inside the particles.
• the crosslinked resin particles (B) When not expanded, the crosslinked resin particles (B) have a relatively large apparent density, preferably exceeding 0.6 g/cm 3 , more preferably 0.7 g/cm 3 or more, and even more preferably 0.9 g/cm 3 or more.
• the apparent density of the crosslinked resin particles (B) can be determined by the method described in JIS K0061 (Method for measuring density and specific gravity of chemical products) or JIS Z8807 (Method for measuring density and specific gravity of solids).
• the average weight per particle of the crosslinked resin particles (B) is not particularly limited, but since the crosslinked resin particles (B) have a small particle size with a volume average particle diameter of 10 ⁇ m or less, the value is far below 0.1 mg.
• the crosslinked resin particles (B) may be dried.
• the shape of the dried particles may be powder, pellets, crumbs, sheets, or the like.
• the crosslinked resin particles (B) can be produced by crosslinking PHA in the presence of peroxide in an aqueous dispersion containing PHA particles before crosslinking treatment. In order to efficiently crosslink PHA, it is preferable to heat the aqueous dispersion of PHA particles containing peroxide to a temperature suitable for decomposing the peroxide.
• the method for producing the crosslinked resin particles (B) preferably includes the steps of: (1) preparing an aqueous dispersion of PHA particles in which the PHA particles before crosslinking treatment are dispersed in water; (2) adding a peroxide to the aqueous dispersion of PHA particles to impregnate the PHA particles with the peroxide; and (3) heating the aqueous dispersion of PHA particles impregnated with the peroxide to a heating temperature to crosslink the PHA. It is even more preferable that the method further includes the step of (4) maintaining the heating temperature after all the peroxide has been added.
• the aqueous dispersion of PHA particles may be an aqueous dispersion obtained by culturing a PHA-producing microorganism to accumulate PHA in the cells, and then disrupting the cells in the culture medium to separate and remove the cell components, or an aqueous dispersion obtained by concentrating or diluting the aqueous dispersion.
• the process from producing PHA particles by culturing a PHA-producing microorganism to crosslinking treatment can be carried out without separating the PHA particles from water.
• an aqueous dispersion of PHA particles can be prepared by dispersing dried PHA particles in water.
• the aqueous dispersion may contain, in addition to water, the above-mentioned organic solvent that is compatible with water.
• the volume average particle diameter of the PHA particles is preferably within the same range as the volume average particle diameter of the crosslinked resin particles (B) described above.
• the volume average particle diameter can usually be within the above range, so that an aqueous dispersion of PHA particles having a desired volume average particle diameter can be obtained without carrying out a special process for adjusting the particle diameter.
• the concentration of PHA particles in the aqueous dispersion is not particularly limited and can be set as appropriate, but may be, for example, about 1 to 70% by weight, and preferably about 5 to 50% by weight.
• the aqueous dispersion of PHA particles preferably contains a dispersant to increase the dispersibility of the PHA particles and to allow the crosslinking reaction to proceed uniformly.
• dispersants include anionic surfactants such as sodium dioctyl sulfosuccinate, sodium dodecyl sulfate, sodium lauryl sulfate, and sodium oleate; cationic surfactants such as lauryl trimethyl ammonium chloride; nonionic surfactants such as glycerin fatty acid esters, sorbitan fatty acid esters, sucrose fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene alkyl phenyl ethers, and polyoxyethylene polyoxypropylene glycol; and water-soluble polymers such as polyvinyl alcohol, ethylene-modified polyvinyl alcohol, polyvinylpyrrolidone, methyl cellulose, ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl
• the amount added is not particularly limited, but may be, for example, 0.1 to 10 parts by weight, and preferably 0.5 to 5 parts by weight, per 100 parts by weight of PHA particles.
• a peroxide is added to the aqueous dispersion of PHA particles obtained in step (1) to impregnate the PHA particles with the peroxide.
• the peroxide may be any of those mentioned above.
• Peroxide may be added in various forms, such as solid or liquid. Alternatively, a liquid form diluted with a diluent may be added. The peroxide may be added all at once, or may be added continuously or in portions.
• the polyfunctional compound may be any of those mentioned above.
• the polyfunctional compound may be added in various forms, such as solid or liquid. A liquid diluted with a diluent or the like may also be added.
• the polyfunctional compound may be added all at once, or may be added continuously or in portions.
• the temperature of the aqueous dispersion is set to, for example, 0°C or higher but lower than a temperature suitable for the decomposition of the peroxide employed in the next step (3), and while stirring the aqueous dispersion, the temperature is maintained, for example, for about 1 minute to 5 hours.
• the temperature of the aqueous dispersion during impregnation may be about 10 to 60°C.
• the amount of peroxide used can be set appropriately taking into consideration the gel fraction of the crosslinked resin particles (B), but for example, it is preferably 0.01 to 10 parts by weight, more preferably 0.1 to 8 parts by weight, even more preferably 0.3 to 5 parts by weight, and particularly preferably 0.5 to 3 parts by weight, per 100 parts by weight of PHA particles.
• the manufacturing method of crosslinking PHA particles in an aqueous dispersion using a peroxide it is easy to obtain crosslinked resin particles by proceeding with crosslinking while maintaining the particle size (volume) before crosslinking.
• the manufacturing method in which PHA particles are crosslinked in an aqueous dispersion using a peroxide makes it easy to control the temperature increase caused by the heat generated during the crosslinking reaction, which is advantageous for efficiently obtaining crosslinked resin particles having a safe and stable crosslinked structure (quality).
• the amount of the polyfunctional compound used may also be set appropriately taking into consideration the gel fraction of the crosslinked resin particles (B). For example, it is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 15 parts by weight, even more preferably 0.1 to 10 parts by weight, even more preferably 0.2 to 5 parts by weight, and particularly preferably 0.3 to 3 parts by weight, per 100 parts by weight of the PHA particles.
• step (3) the aqueous dispersion of PHA particles impregnated with peroxide is heated to a temperature suitable for decomposing the peroxide.
• the heating temperature is preferably within a range of about 25°C above or below the one-hour half-life temperature of the peroxide described above. Specifically, the heating temperature is preferably 30 to 140°C, more preferably 50 to 135°C, and even more preferably 60 to 130°C. According to this method, it is possible to crosslink the PHA at a temperature lower than the melting temperature of the PHA, so deterioration of the PHA due to heating during the crosslinking process can be avoided.
• the heating temperature is maintained. This allows the crosslinking reaction using peroxide to proceed sufficiently.
• the time for which the heating temperature is maintained is not particularly limited, but is preferably 1 minute to 15 hours, and more preferably 1 hour to 10 hours.
• the crosslinked resin particles (B) are separated from the aqueous dispersion and the water is removed to obtain dried crosslinked resin particles (B).
• the method for separating the crosslinked resin particles (B) is not particularly limited, and for example, filtration, centrifugation, heat drying, freeze drying, spray drying, etc. can be used.
• spray drying can be used to obtain dried crosslinked resin particles (B) directly from the aqueous dispersion.
• the crosslinked resin particles (B) can be obtained in pellet form while completely removing the remaining moisture.
• an aggregation process using a coagulant or pH adjustment may be performed.
• the amount of crosslinked resin particles (B) is 1 to 60 parts by weight per 100 parts by weight of the total of polylactic acid (A) and crosslinked resin particles (B).
• the amount is preferably 2 parts by weight or more, more preferably 3 parts by weight or more, and particularly preferably 5 parts by weight or more.
• the upper limit of the amount is preferably 55 parts by weight or less, more preferably 50 parts by weight or less, and particularly preferably 45 parts by weight or less.
• thermoplastic resin composition contains polylactic acid (A) as a thermoplastic resin that is a matrix resin.
• Polylactic acid is a polyester resin that contains lactic acid as a constituent monomer and has biodegradability.
• polylactic acid any conventionally known polylactic acid can be used, and it may be either crystalline or amorphous.
• the polylactic acid may be a homopolymer of lactic acid, a copolymer of lactic acid and another monomer, or a blend thereof.
• the other monomers include aliphatic hydroxycarboxylic acids other than lactic acid, aliphatic polyhydric alcohols, aliphatic polycarboxylic acids, and polyfunctional polysaccharides.
• the lactic acid constituting the polylactic acid may be either the L-form or the D-form, or may contain both. In the latter case, the ratio of the L-form to the D-form is not particularly limited.
• the polylactic acid which is a homopolymer may be any one of poly(L-lactic acid) resin, poly(D-lactic acid) resin, and poly(DL-lactic acid) resin, or may be a blend of these.
• aliphatic hydroxycarboxylic acid other than lactic acid examples include glycolic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 5-hydroxyvaleric acid, and 6-hydroxycaproic acid. Lactones such as caprolactone, valerolactone, propiolactone, and undecalactone can also be used.
• Examples of the aliphatic polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, decanediol, neopentyl glycol, tetramethylene glycol, 1,4-cyclohexanedimethanol, glycerin, pentaerythritol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc.
• Examples of the aliphatic polycarboxylic acid include oxalic acid, succinic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, sebacic acid, azelaic acid, and cyclohexanedicarboxylic acid.
• the aliphatic polycarboxylic acid may be an anhydride.
• polyfunctional polysaccharides examples include cellulose, cellulose nitrate, methylcellulose, ethylcellulose, celluloid, viscose rayon, regenerated cellulose, cellophane, cupra, cuprammonium rayon, cuprophane, Bemberg, hemicellulose, starch, acropectin, dextrin, dextran, glycogen, pectin, chitin, chitosan, gum arabic, guar gum, locust bean gum, and acacia gum.
• polylactic acid is a copolymer of lactic acid and other monomers
• the content of the other monomers is preferably about 0 to 3 mol %, and more preferably 0 to 2 mol %, of the total monomers contained in polylactic acid.
• the lactic acid raw material for producing polylactic acid is not particularly limited either, and L-lactic acid, D-lactic acid, DL-lactic acid, or a mixture thereof, or L-lactide, D-lactide, meso-lactide, or a mixture thereof, etc., can be used. Lactic acid obtained by microbial fermentation from renewable raw materials derived from plants such as starch can be suitably used.
• the method for producing polylactic acid is not particularly limited, and any known method such as dehydration condensation polymerization or ring-opening polymerization can be used.
• the molecular weight of polylactic acid (A) is not particularly limited, but the weight average molecular weight is preferably 50,000 to 1,000,000, more preferably 70,000 to 700,000, and more preferably 100,000 to 400,000. By making the weight average molecular weight 50,000 or more, sufficient rigidity and strength can be obtained in the thermoplastic resin composition according to this embodiment. On the other hand, polylactic acid with a weight average molecular weight of more than 1,000,000 may be difficult to prepare by itself or to handle in order to achieve the object of the present invention.
• the thermoplastic resin composition may contain a thermoplastic resin other than polylactic acid in addition to polylactic acid.
• thermoplastic resins are not particularly limited, but may include polyolefin resins such as polyethylene and polypropylene, acrylic resins such as polyvinyl chloride, polystyrene, polyvinyl acetate, polyurethane, polytetrafluoroethylene, and polymethyl methacrylic acid, AS resins, polyamides, polyacetals, polycarbonates, modified polyphenylene ethers, polyester resins, and cyclic polyolefins. These thermoplastic resins may be used alone or in combination of two or more.
• polyester resins are particularly preferred.
• polyester resins include PHAs such as polyglycolic acid, P3HA, and poly(4-hydroxyalkanoate) resins; aliphatic polyesters having a structure in which an aliphatic diol and an aliphatic dicarboxylic acid are polycondensed; and aliphatic aromatic polyesters having both an aliphatic compound and an aromatic compound as monomers.
• aliphatic polyesters other than PHAs include polycaprolactone, polyethylene succinate, polybutylene succinate (PBS), polyhexamethylene succinate, polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, polybutylene succinate adipate (PBSA), polyethylene sebacate, and polybutylene sebacate.
• PBS polybutylene succinate
• PBSA polyhexamethylene adipate
• PBSA polyhexamethylene adipate
• sebacate polybutylene sebacate
• polyesters examples include poly(butylene adipate-co-butylene terephthalate) (PBAT), poly(butylene sebacate-co-butylene terephthalate), poly(butylene azelate-co-butylene terephthalate), poly(butylene succinate-co-butylene terephthalate) (PBST), etc. These polyester resins may be used alone or in combination of two or more types.
• the content of the thermoplastic resin other than polylactic acid is not particularly limited, but may be, for example, about 0 to 100 parts by weight per 100 parts by weight of polylactic acid (A). In addition, the content may be 50 parts by weight or less, 30 parts by weight or less, 10 parts by weight or less, 5 parts by weight or less, or 1 part by weight or less.
• the thermoplastic resin composition may further contain a crystal nucleating agent.
• a crystal nucleating agent in the case where the polylactic acid (A) is a crystalline resin, crystallization during molding is promoted, and molding processability, productivity, etc. can be improved. Furthermore, a thermoplastic resin composition having excellent heat resistance or mechanical properties can be obtained.
• the crystal nucleating agent is not particularly limited, and conventionally known ones can be used, for example, inorganic substances such as talc, kaolinite, montmorillonite, mica, synthetic mica, clay, zeolite, silica, carbon black, graphite, boron nitride, zinc oxide, titanium oxide, tin oxide, calcium carbonate, magnesium carbonate, aluminum oxide, neodymium oxide, barium sulfate, sodium chloride, metal phosphates, etc.; sugar alcohol compounds derived from natural products such as erythritol, pentaerythritol, galactitol, mannitol, arabitol, etc.; polysaccharides such as chitin and chitosan; polyols such as aliphatic alcohols (polyols), polyvinyl alcohol, polyethylene oxide, etc.; sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzo
• organic carboxylic acid metal salts such as lithium, lithium terephthalate, sodium terephthalate, potassium terephthalate, calcium oxalate, sodium laurate, potassium laurate, sodium myristate, potassium myristate, calcium myristate, sodium octacosanoate, calcium octacosanoate, sodium stearate, potassium stearate, lithium stearate, calcium stearate, magnesium stearate, barium stearate, sodium montanate, calcium montanate, sodium toluate, sodium salicylate, potassium salicylate, zinc salicylate, aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium ⁇ -naphthalate, and sodium cyclohexanecarboxylate; p-toluenesulfone organic sulfonates such as sodium sulfoisophthalate and sodium stearate; carboxylic acid amides such as ethylene stearic acid
• the content of the crystal nucleating agent is not particularly limited as long as it can promote the crystallization of polylactic acid (A), but it is preferably 0.05 to 12 parts by weight, more preferably 0.1 to 10 parts by weight, and even more preferably 0.5 to 8 parts by weight, per 100 parts by weight of polylactic acid (A).
• the content of the crystal nucleating agent is within the above range, it is possible to obtain the effect of the crystal nucleating agent while suppressing the decrease in viscosity during molding and the physical properties of the molded product.
• the thermoplastic resin composition may further contain a lubricant.
• a lubricant By containing a lubricant, the surface smoothness of the obtained molded body may be improved.
• the lubricant is not particularly limited, but examples thereof include fatty acid metal salts such as magnesium stearate and calcium stearate, fatty acid amides such as behenic acid amide, stearic acid amide, erucic acid amide, oleic acid amide methylene bis stearic acid amide, and ethylene bis stearic acid amide; polyethylene wax, oxidized polyester wax, glycerin mono fatty acid esters such as glycerin monostearate, glycerin monobehenate, and glycerin monolaurate; organic acid monoglycerides such as succinic acid saturated fatty acid monoglycerides; sorbitan fatty acid esters such as sorbitan behenate, sorbitan stearate, and sorbit
• the content of the lubricant (the total content when multiple lubricants are used) is not particularly limited as long as it can impart lubricity to the molded body, but is preferably 0.01 to 20 parts by weight, more preferably 0.05 to 10 parts by weight, even more preferably 0.1 to 10 parts by weight, even more preferably 0.2 to 5 parts by weight, and particularly preferably 0.3 to 4 parts by weight, per 100 parts by weight of polylactic acid (A).
• the content of the lubricant is within the above range, it is possible to obtain the effect of the lubricant while avoiding bleeding out of the lubricant onto the surface of the molded body.
• thermoplastic resin composition according to this embodiment may contain other components, such as a plasticizer, an organic filler, an inorganic filler, an antioxidant, a hydrolysis inhibitor, an ultraviolet absorber, a colorant such as a dye or a pigment, and an antistatic agent, to the extent that the functionality of the resulting molded article is not impaired.
• the plasticizer is not particularly limited, but may be a polyester-based plasticizer such as polypropylene glycol sebacate; an aliphatic dibasic acid ester-based plasticizer such as di-1-butyl adipate, di-n-butyl sebacate, and di-2-ethylhexyl azelate; a glycerin-based plasticizer such as glycerin diacetomonolaurate, glycerin diacetomonocaprylate, and glycerin diacetomonodecanoate; a polyvalent carboxylic acid ester-based plasticizer such as tri-2-ethylhexyl acetyl citrate and tributyl acetyl citrate; polyethylene glycol, polypropylene glycol, poly(ethylene oxide-propylene oxide) block and/or random copolymer, polytetramethylene glycol, etc.
• a polyester-based plasticizer such as polypropylene glycol sebacate
• polyalkylene glycol-based plasticizers such as diphenyl-2-ethylhexyl phosphate and diphenyloctyl phosphate; epoxy-based plasticizers such as epoxidized soybean oil and epoxidized linseed oil fatty acid butyl ester; castor oil-based plasticizers such as castor oil fatty acid ester, methyl ricinoleate, ethyl ricinoleate, isopropyl ricinoleate, butyl ricinoleate, ethylene glycol monoricylate, propylene glycol monoricylate, trimethylolpropane monoricylate, sorbitan monoricylate, castor oil fatty acid polyethylene glycol ester, castor oil ethylene oxide adduct, castor oil-based polyol, castor oil-based toluol, and castor oil-based diol. These may be used alone or in combination of two or more.
• the organic filler is not particularly limited, but examples include fillers made of wood-based materials such as wood chips, wood flour, and sawdust, and naturally derived materials such as rice husks, rice flour, starch, corn starch, rice straw, wheat straw, and natural rubber; organic fibers such as natural plant fibers, natural animal fibers, and synthetic fibers; and fillers made of synthetic resin materials such as polyester, polyacrylic, polyamide, nylon, polyethylene, polyolefin, polyvinyl alcohol, polyvinyl chloride, polyurethane, polyacetal, aramid, PBO (poly-p-phenylene benzobisoxazole), polyphenylene sulfide, acetyl cellulose, polybenzazole, polyarylate, polyvinyl acetate, and synthetic rubber.
• wood-based materials such as wood chips, wood flour, and sawdust, and naturally derived materials such as rice husks, rice flour, starch, corn starch, rice straw, wheat straw, and natural rubber
• Examples of the natural plant fibers include kenaf fiber, abaca fiber, bamboo fiber, jute fiber, hemp fiber, linen fiber, henequen (sisal), ramie fiber, hemp, cotton, banana fiber, coconut fiber, palm, paper mulberry, mitsumata, bagasse, etc.
• Other examples include pulp and cellulose fibers processed from plant fibers, and regenerated fibers such as rayon.
• Examples of natural animal fibers include wool, silk, cashmere, mohair, etc.
• the inorganic filler is not particularly limited, but examples thereof include quartz, fumed silica, silicic anhydride, fused silica, crystalline silica, amorphous silica, fillers obtained by condensing alkoxysilanes, silica-based inorganic fillers such as ultrafine amorphous silica, alumina, zircon, iron oxide, zinc oxide, titanium oxide, silicon nitride, boron nitride, aluminum nitride, silicon carbide, glass, silicone rubber, silicone resin, titanium oxide, carbon fiber, mica, graphite, carbon black, ferrite, graphite, diatomaceous earth, white clay, clay, talc, calcium carbonate, manganese carbonate, magnesium carbonate, barium sulfate, silver powder, and the like. These may be surface-treated to increase dispersibility in the resin composition. These may be used alone or in combination of two or more.
• the antioxidant is not particularly limited, but examples thereof include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. These may be used alone or in combination of two or more.
• the hydrolysis inhibitor is not particularly limited, but examples thereof include carbodiimide compounds, epoxy compounds, isocyanate compounds, oxazoline compounds, etc. These may be used alone or in combination of two or more.
• the ultraviolet absorbing agent is not particularly limited, but examples thereof include benzophenone compounds, benzotriazole compounds, triazine compounds, salicylic acid compounds, cyanoacrylate compounds, nickel complex compounds, etc. These may be used alone or in combination of two or more.
• the colorants such as pigments and dyes are not particularly limited, but examples include inorganic colorants such as titanium oxide, calcium carbonate, chromium oxide, cuprous oxide, calcium silicate, iron oxide, carbon black, graphite, titanium yellow, and cobalt blue; soluble azo pigments such as lake red, lithol red, and brilliant carmine; insoluble azo pigments such as dinitrile orange and fast yellow; phthalocyanine pigments such as monochlorophthalocyanine blue, polychlorophthalocyanine blue, and polybromophthalocyanine green; condensed polycyclic pigments such as indigo blue, perylene red, isoindolinone yellow, and quinacridone red; and dyes such as oracet yellow. These may be used alone or in combination of two or more.
• the antistatic agent is not particularly limited, but examples thereof include low molecular weight antistatic agents such as fatty acid ester compounds, aliphatic ethanolamine compounds, and aliphatic ethanolamide compounds, and polymeric antistatic agents. These may be used alone or in combination of two or more.
• the thermoplastic resin composition according to this embodiment may also contain catalyst deactivators (hindered phenol compounds, thioether compounds, vitamin compounds, triazole compounds, polyamine compounds, hydrazine derivative compounds, phosphorus compounds, etc.), release agents (montanic acid and its salts, its esters, its half esters, stearyl alcohol, stearamide, polyethylene wax, etc.), color inhibitors (phosphites, hypophosphites, etc.), silane coupling agents (epoxy silane coupling agents, amino silane coupling agents, (meth)acrylic silane coupling agents, isocyanate silane coupling agents, etc.), flame retardants (red phosphorus, phosphate esters, brominated polystyrene, brominated polyphenylene ether, etc.), and the like.
• catalyst deactivators hindered phenol compounds, thioether compounds, vitamin compounds, triazole compounds, polyamine compounds, hydrazine derivative compounds, phosphorus compounds, etc.
• release agents
• thermoplastic resin composition according to the present embodiment can be produced by a known method. Specifically, the polylactic acid (A), the crosslinked resin particles (B), and other optional components can be melt-kneaded using an extruder, a kneader, a Banbury mixer, a kneading roll, or the like. When melt-kneading, it is preferable to mix while paying attention to the decrease in molecular weight due to thermal decomposition.
• the thermoplastic resin composition can also be produced by dissolving each component in a soluble solvent and then removing the solvent.
• each component When manufacturing by melt kneading, each component may be fed separately into an extruder, etc., or each component may be mixed in advance and then fed into an extruder, etc.
• an aqueous dispersion of polylactic acid (A) and an aqueous dispersion of crosslinked resin particles (B) may be mixed and then dried to obtain a mixed powder, which may then be fed into an extruder, etc.
• the resulting thermoplastic resin composition may be extruded into strands and then cut to process into particle shapes such as bars, cylinders, elliptical cylinders, spheres, cubes, rectangular prisms, etc.
• the resin temperature during melt kneading cannot be generally defined because it depends on the melting point and melt viscosity of the resin used, but from the viewpoint of uniformly dispersing the crosslinked resin particles (B) while avoiding thermal decomposition of the polylactic acid (A), it is preferably 140 to 250°C, more preferably 150 to 230°C, and even more preferably 160 to 210°C.
• a molded article can be produced from the thermoplastic resin composition according to the present embodiment.
• the molding method is not particularly limited, and any commonly used molding method can be used, specifically, inflation film molding, extrusion blow molding, injection blow molding, extrusion molding, calendar molding, vacuum molding, injection molding, press molding, etc.
• these molding methods can produce molded products with improved impact resistance, specifically, sheets, films, blow molded products, extrusion molded products, vacuum molded products, and injection molded products, with good productivity.
• the molded article made from the thermoplastic resin composition according to this embodiment can be suitably used in the fields of agriculture, fisheries, forestry, horticulture, medicine, hygiene products, the food industry, clothing, non-clothing, packaging, automobiles, building materials, and other fields.
• [Item 1] 40 to 99 parts by weight of polylactic acid (A), and A thermoplastic resin composition comprising: 1 to 60 parts by weight of crosslinked resin particles (B) containing a polyhydroxyalkanoate resin and having a gel fraction of 50% or more (wherein the total amount of (A) and (B) is 100 parts by weight).
• a thermoplastic resin composition comprising: 1 to 60 parts by weight of crosslinked resin particles (B) containing a polyhydroxyalkanoate resin and having a gel fraction of 50% or more (wherein the total amount of (A) and (B) is 100 parts by weight).
• thermoplastic resin composition according to item 1 or 2 wherein the crosslinked resin particles (B) have a volume average particle size of 0.1 ⁇ m or more and 10 ⁇ m or less.
• the thermoplastic resin composition according to any one of items 1 to 3 wherein the crosslinked resin particles (B) are crosslinked using a peroxide.
• the thermoplastic resin composition according to any one of items 1 to 4 wherein the crosslinked resin particles (B) are further crosslinked in the presence of a polyfunctional compound.
• thermoplastic resin composition according to any one of items 1 to 5 wherein the crosslinked resin particles (B) are not foamed.
• 7 7.
• thermoplastic resin composition according to any one of items 1 to 6, wherein the proportion of the polyhydroxyalkanoate resin in the crosslinked resin particles (B) is 80% by weight or more.
• 9 A molded article of the thermoplastic resin composition according to any one of items 1 to 8.
• 10 10. The molded article according to item 9, which is a sheet, a film, a blow molded article, an extrusion molded article, a vacuum molded article, or an injection molded article.
• a modifier for polylactic acid comprising crosslinked resin particles (B) which contain a polyhydroxyalkanoate resin and have a gel fraction of 50% or more.
• volume average particle diameter The volume average particle diameter of the crosslinked resin particles or the uncrosslinked resin particles was measured in the form of particle latex.
• the measuring device used was a Microtrac MT3300EXII manufactured by Nikkiso Co., Ltd.
• Peroxide PO-1 t-butyl peroxypivalate ("Luperox 11" manufactured by Arkema Yoshitomi Co., Ltd., 1-hour half-life temperature: 76°C)
• PO-2 t-butylperoxy-2-ethylhexyl monocarbonate ("Perbutyl E” manufactured by NOF Corporation, 1-hour half-life temperature: 119°C)
• PO-3 Di(secondary butyl) peroxydicarbonate ("Luperox 225" manufactured by Arkema Yoshitomi Co., Ltd., 1-hour half-life temperature: 69°C)
• PO-4 t-Butylperoxy-2-ethylhexanoate ("Luperox 26" manufactured by Arkema Yoshitomi Co., Ltd., 1-hour half-life temperature: 95°C) 2-3.
• CA-2 Triallyl isocyanurate
• the volume average particle size and gel fraction of the uncrosslinked resin particles before the crosslinking reaction were measured by the above-mentioned method, and the results are shown in Table 1 as Reference Example 1.
• the uncrosslinked resin particles were used in Comparative Example 5 described in Table 2.
• test pieces Examples 1 to 8 and Comparative Examples 1 to 5
• the mixture of (a) and (b) was kneaded for 180 seconds in a twin-screw small kneader (Xplore MC5 manufactured by DSM) with the barrel temperature heated to 175° C. and the screw rotation speed was 100 rpm to obtain a kneaded product.
• This kneaded product was dried in a dryer at 90° C. for 2 hours to sufficiently reduce the moisture content, and then press-molded to a predetermined thickness at 170° C. to prepare a test piece.
• Tensile test conditions The 200 ⁇ m thick sheet prepared by the above method was aged for 7 days under conditions of 23° C. and 50% RH, and then the tensile properties were measured at 23° C. at a test speed of 100 mm/min. using a tensile tester (Shimadzu Corporation: EZ-LX 1 kN) according to the method of JIS K 7127. The results are shown in Table 2.
• Tensile impact strength measurement conditions The 500 ⁇ m thick sheet prepared by the above method was aged for 7 days under conditions of 23° C. and 50% RH, and then punched into JIS K 71603 type test pieces and subjected to a tensile impact test according to JIS K 7160 A method. The results are shown in Table 2.

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• 2023
  • 2023-10-25 WO PCT/JP2023/038547 patent/WO2024090484A1/ja not_active Ceased
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