JP2007161957A - Resin composition and molding comprising the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a resin composition that has excellent mechanical properties and heat resistance and exhibits excellent moldability by controlling occurrence of warpage in molding and reduction in weld strength and a molding obtained from the resin composition. <P>SOLUTION: The resin composition comprises a biodegradable thermoplastic resin (A), a fibrous reinforcing material (B) and a spherical reinforcing material (C) in which the biodegradable thermoplastic resin (A) is crosslinked with a (meth) acrylic acid ester compound (D) The molding comprises the resin composition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a resin composition comprising a crosslinked biodegradable polyester resin, a fibrous reinforcing material, and a spherical reinforcing material, and a molded article comprising the same. More specifically, the present invention relates to a resin composition excellent in mechanical properties and heat resistance, small in molding shrinkage anisotropy and warp deformation, and excellent in weld strength, and a molded body comprising the same.

In recent years, biodegradable polyester resins such as polylactic acid have attracted attention from the viewpoint of environmental conservation. Among the biodegradable resins, polylactic acid, polyethylene succinate, polybutylene succinate and the like are inexpensive and are highly useful because they can be mass-produced. However, these biodegradable polyesters have the disadvantage that they are inferior in mechanical properties and heat resistance compared to non-biodegradable resins such as polypropylene, polyethylene terephthalate, and polycarbonate.
Although polylactic acid has a high glass transition point (Tg) and excellent heat resistance as compared with other biodegradable resins, it cannot necessarily be said to have high heat resistance in the temperature range above Tg. In addition, since the crystallization speed is slow, normal molded products often have insufficient mechanical properties, heat resistance, etc., so it is necessary to increase the molding cycle of injection molding. It could not be said that the nature was high.

As a method for improving the mechanical properties of the biodegradable polyester resin, Patent Document 1 proposes a method of reinforcing polylactic acid by filling with an inorganic filler or a fibrous reinforcing material. However, although the rigidity at room temperature is improved to some extent, the crystallinity of polylactic acid itself is not high, so the rigidity and toughness are lowered in the temperature range exceeding the glass transition temperature, and it is difficult to obtain sufficient heat resistance. .
In addition, in order to accelerate the crystallization and improve the heat resistance and productivity, the present applicant adds a (meth) acrylic ester compound to the biodegradable polyester and crosslinks it first. This is proposed in Patent Document 2. However, although this method improves the crystallization speed, the effect may not be sufficient. In addition, when this crosslinked polylactic acid is reinforced with a fibrous reinforcing material such as glass fiber, there is a large difference in the molding shrinkage rate in the direction perpendicular to the arrangement direction (flow direction) and the arrangement direction of the fibrous reinforcement ( Anisotropy) and warpage of the molded product. For this reason, a plate-shaped molded product, a box-shaped molded product, a molded product with a large variation in wall thickness, and the like have a large warp deformation at the time of molding, and it has not been possible to obtain a molded product that can be used in appearance or practically. In addition, since the weld strength is remarkably reduced, there is a problem that it cannot be used for a part having a shape in which a lot of welds are generated at the time of molding.
JP 2002-105298 A JP 2003-128901 A

  The present invention solves the above-mentioned problems and is excellent in mechanical properties and heat resistance, and also has excellent moldability by suppressing warpage generation and weld strength reduction during molding. The object is to provide an article and a molded article obtained thereby.

As a result of intensive studies to solve the above problems, the present inventors have solved the above problems by using a cross-linked biodegradable polyester resin, a fibrous reinforcing material, and a spherical reinforcing material in combination. The present invention has been found.
That is, the gist of the present invention is as follows.
(1) Biodegradable polyester resin (A) 50 to 90 parts by mass, fibrous reinforcement (B) 5 to 45 parts by mass, spherical reinforcement (C) 5 to 45 parts by mass, biodegradable The resin composition, wherein the polyester resin (A) is crosslinked with a (meth) acrylic acid ester compound (D).
(2) 0.01 to 10 parts by mass of (meth) acrylic acid ester compound (D) is blended with respect to 100 parts by mass of biodegradable polyester resin (A). Resin composition.
(3) The resin composition according to (1) or (2), wherein the biodegradable polyester resin (A) contains a polylactic acid resin as a main component.
(4) The resin composition according to any one of (1) to (3), wherein the fibrous reinforcing material (B) is a glass fiber.
(5) The resin composition according to any one of (1) to (4), wherein the spherical reinforcing material (C) is a glass bead.
(6) The (meth) acrylic acid ester compound (D) has two or more (meth) acrylic groups in the molecule, or one or more (meth) acrylic groups and one or more glycidyl groups or vinyl. The resin composition according to any one of (1) to (5), which is a compound having a group.
(7) A molded article comprising the resin composition according to any one of (1) to (6) above.

  According to the present invention, a resin composition having excellent mechanical properties and heat resistance, and having excellent moldability by suppressing generation of warpage during molding and reduction in weld strength is provided. Since this resin composition has reduced restrictions at the time of designing a molded product, it can be made into various molded products by various molding methods, and thus has an extremely high industrial utility value. In addition, if a biodegradable resin derived from a natural product is used, it can contribute to saving depleted resources such as petroleum.

Hereinafter, the present invention will be described in detail.
Examples of the biodegradable polyester resin (A) used in the present invention include polylactic acid such as poly (L-lactic acid) and poly (D-lactic acid), polyglycolic acid, poly (3-hydroxybutyric acid), and poly (3 -Hydroxyvaleric acid), poly (3-hydroxycaproic acid), polycaprolactone, polybutylene succinate, polyethylene succinate, polybutylene adipate terephthalate, polybutylene succinate terephthalate, etc., and mixtures and Coalescence can also be used. From the viewpoint of saving petroleum resources, plant-derived raw materials are preferable, and in particular, poly (L-lactic acid), poly (D-lactic acid), and a mixture or copolymer thereof are used in terms of heat resistance and moldability. desirable. A stereocomplex may be made by mixing L-lactic acid and D-lactic acid.

  The melting point (Tm) of polylactic acid mainly composed of poly (L-lactic acid) varies depending on the optical purity, but in the present invention, considering the mechanical properties and heat resistance of the molded product, Tm is It is preferable to set it to 160 degreeC or more. In order to make Tm 160 ° C. or higher in polylactic acid mainly composed of poly (L-lactic acid), the ratio of the D-lactic acid component may be less than about 3 mol%.

  The melt flow rate of the biodegradable polyester resin (A) at 190 ° C. and a load of 21.2 N is 0.1 to 50 g / 10 minutes, preferably 0.2 to 20 g / 10 minutes, and optimally 0.5 to 15 g. / 10 minutes. When the melt flow rate exceeds 50 g / 10 min, the melt viscosity is too low, and the mechanical properties and heat resistance of the molded product may be inferior. On the other hand, when the melt flow rate is less than 0.1 g / 10 minutes, the load during the molding process becomes too high, and the operability may be lowered.

  The biodegradable polyester resin (A) is produced by a known melt polymerization method and, if necessary, a solid phase polymerization method in combination.

  The molecular weight of the biodegradable polyester resin is not particularly limited, but the weight average molecular weight is preferably 50,000 or more and 1,000,000 or less, and more preferably 80,000 or more and 1,000,000 or less. When the weight average molecular weight is less than 50,000, the melt viscosity of the resin composition is too low, and the mechanical properties and heat resistance of the molded product may be inferior. Conversely, if it exceeds 1,000,000, the moldability of the resin composition may be reduced.

  As the (meth) acrylic acid ester compound (D), the reactivity with the biodegradable resin is high, the monomer hardly remains, the toxicity is relatively low, and the resin is less colored. Compounds having (meth) acrylic groups or having one or more (meth) acrylic groups and one or more glycidyl groups or vinyl groups are preferred. Specifically, glycidyl methacrylate, glycidyl acrylate, glycerol dimethacrylate, Methylolpropane trimethacrylate, trimethylolpropane triacrylate, allyloxy polyethylene glycol monoacrylate, allyloxy polyethylene glycol monomethacrylate, polyethylene glycol dimethacrylate, polyethylene glycol diacrylate, polypropylene glycol Dimethacrylate, Polypropylene glycol diacrylate, Polytetramethylene glycol dimethacrylate (The alkylene glycol part may be an alkylene copolymer of various lengths), Ethylene glycol dimethacrylate, Diethylene glycol dimethacrylate, Butanediol methacrylate And butanediol acrylate. Among them, polyethylene glycol dimethacrylate, polypropylene glycol dimethacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate and the like are preferable because of safety and reactivity.

  The blending amount of the (meth) acrylic acid ester compound (D) is preferably 0.01 to 10 parts by mass, more preferably 0 with respect to 100 parts by mass of the biodegradable polyester resin (A). .05 to 10 parts by mass, more preferably 0.05 to 5 parts by mass. If it is less than 0.01 parts by mass, the heat resistance and moldability intended by the present invention cannot be obtained, and if it exceeds 10 parts by mass, the degree of crosslinking may be too strong, which may impair operability. .

  When the (meth) acrylic acid ester compound (D) is melt-kneaded with the biodegradable polyester resin (A), it is preferable to add a peroxide as a crosslinking aid because the degree of crosslinking can be increased. As the peroxide, an organic peroxide having good dispersibility in the resin is preferable. Specifically, benzoyl peroxide, bis (butylperoxy) trimethylcyclohexane, bis (butylperoxy) methylcyclododecane, butylbis (Butylperoxy) valerate, dicumyl peroxide, butylperoxybenzoate, dibutyl peroxide, bis (butylperoxy) diisopropylbenzene, dimethyldi (butylperoxy) hexane, dimethyldi (butylperoxy) hexyne, butylperoxycumene Etc. 0.1-10 mass parts is preferable with respect to 100 mass parts of biodegradable polyester resins, and, as for the compounding quantity of the said peroxide, More preferably, it is 0.1-5 mass parts. If it is less than 0.1 parts by mass, the effect of increasing the degree of crosslinking is low, and if it exceeds 10 parts by mass, it is not preferable in terms of cost.

  The method for crosslinking with the (meth) acrylate compound (D) is not particularly limited, but a method of melt-kneading the biodegradable polyester resin (A) and the (meth) acrylate compound (D) is possible. The simplest. In order to improve the kneading state, it is preferable to use a twin screw extruder. The kneading temperature is preferably in the range of (Tm + 5 ° C. of biodegradable polyester resin) to (Tm + 100 ° C. of biodegradable polyester resin), and the kneading time is preferably 20 seconds to 30 minutes. If the temperature is lower or shorter than this range, kneading or reaction becomes insufficient, and if the temperature is higher or longer, the resin may be decomposed or colored. In blending, if the (meth) acrylic acid ester compound (D) is in a solid state, a method using a dry blend or a powder feeder is preferable. If in a liquid state, an extruder using a pressure pump is used. A method of injecting from the middle is preferable.

  As a preferable method when the (meth) acrylic ester compound (D) and the peroxide are used in combination, the (meth) acrylic ester compound (D) and / or the peroxide is dissolved or dispersed in a medium and mixed in a kneader. The method of inject | pouring is mentioned and operativity can be improved significantly. That is, during melt-kneading of the biodegradable polyester resin (A) and the peroxide, a solution or dispersion of the (meth) acrylic ester compound (D) is injected, or the biodegradable polyester resin ( During melt kneading of A), a solution or dispersion of (meth) acrylic acid ester compound (D) and peroxide can be injected and melt kneaded.

  As the medium for dissolving or dispersing the (meth) acrylic acid ester compound (D) and / or the peroxide, a conventionally known medium is used, and is not particularly limited, but the biodegradable polyester resin (A) of the present invention and A plasticizer having excellent compatibility is preferred. For example, one or more selected from aliphatic polycarboxylic acid ester derivatives, aliphatic polyhydric alcohol ester derivatives, aliphatic oxyester derivatives, aliphatic polyether derivatives, aliphatic polyether polycarboxylic acid ester derivatives, etc. Examples include plasticizers. Specific examples of the compound include dimethyl adipate, dibutyl adipate, triethylene glycol diacetate, methyl acetyl ricinoleate, acetyl tributyl citric acid, polyethylene glycol, and dibutyl diglycol succinate. As a usage-amount of a plasticizer, 30 mass parts or less are preferable with respect to a total of 100 mass parts of a biodegradable polyester resin (A), a fibrous reinforcement (B), and a spherical reinforcement (C), 0.1-20 Part by mass is more preferable. When the reactivity of the crosslinking agent is low, it is not necessary to use a plasticizer. However, when the reactivity is high, it is preferable to use 0.1 parts by mass or more. In addition, since this medium may volatilize at the time of mixing with resin, even if it uses it at the time of manufacture, this medium may not be contained in the obtained resin composition.

  Specific examples of the fibrous reinforcing material (B) used in the present invention include glass fiber, carbon fiber, natural fiber typified by kenaf, etc. Among them, glass from the viewpoint of mechanical properties, heat resistance, and cost. Fiber is preferred. In order to improve the adhesion to the biodegradable polyester resin (A), the fibrous reinforcing material is a silane coupling agent, a titanium coupling agent, etc., for example, γ-aminopropyltrimethoxysilane, N-β- Aminosilanes such as (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyldimethoxymethylsilane, γ-glycidoxypropyltrimethoxysilane, γ-glycididoxypropyl Titanium couplings such as epoxysilanes such as ethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, isopropyltristearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, tetraisopropylbis (dioctylphosphite) titanate What was surface-treated with a coupling agent such as an agent is preferred. These may be used alone or in combination.

  The length of the fibrous reinforcing material (B) is preferably 1 to 25 mm, and more preferably 3 to 15 mm. The longer the fiber length, the greater the reinforcing effect and the higher the flexural modulus. If the fiber length is less than 1 mm, a sufficient reinforcing effect due to the fiber length cannot be obtained, and if the fiber length exceeds 25 mm, the fluidity is greatly lowered, which is not preferable in terms of moldability.

  The fiber diameter of the fibrous reinforcing material (B) is preferably 1 to 30 μm, and more preferably 5 to 20 μm. When the fiber diameter is less than 1 μm, a sufficient reinforcing effect cannot be obtained, and when the fiber diameter exceeds 30 mm, it is not preferable in terms of formability.

  The compounding quantity of a fibrous reinforcement (B) needs to be 5-45 mass parts with respect to 50-90 mass parts of biodegradable polyester resin (A), and it is preferable that it is 10-30 mass parts. . If the blending amount of the fibrous reinforcing material (B) is less than 5 parts by mass, sufficient mechanical properties and heat resistance cannot be obtained. When the blending amount of the fibrous reinforcing material (B) exceeds 45 parts by mass, the specific gravity of the mixture becomes too large and the fluidity is lowered, so that the moldability is deteriorated. In addition, since the fibers float on the surface at the time of molding, the appearance is deteriorated, which is not preferable.

  Specific examples of the spherical reinforcing material (C) used in the present invention include alkali glass beads, low alkali glass beads, spherical silica, spherical alumina, etc. Among them, glass beads are preferable from the viewpoint of cost, and biodegradable. Low alkali glass beads are more preferable in order to suppress degradation of the polyester resin as much as possible. Since the spherical reinforcing material (C) improves the adhesion to the biodegradable polyester resin (A), a silane coupling agent, a titanium coupling agent, etc., for example, γ-aminopropyltrimethoxysilane, N-β Aminosilanes such as-(aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyldimethoxymethylsilane, γ-glycidoxypropyltrimethoxysilane, γ-glycycidoxy Titanium cups such as epoxy silanes such as propylethoxysilane and β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, isopropyltristearoyl titanate, isopropyltridodecylbenzenesulfonyl titanate, tetraisopropylbis (dioctylphosphite) titanate Rin The surface treatment may be performed with a coupling agent such as an adhesive.

  The weight average particle diameter of the spherical reinforcing material (C) is preferably 1 to 300 μm, and more preferably 10 to 100 μm. If the weight average particle diameter is less than 1 μm, an agglomerate is likely to occur due to poor dispersion, and a uniform molded product cannot be obtained, and mechanical properties may be deteriorated. If the weight average particle size exceeds 300 μm, it may not be possible to obtain a sufficient warp reduction effect or weld strength reduction suppression effect, which is not preferable.

  The compounding amount of the spherical reinforcing material (C) needs to be 5 to 45 parts by mass, preferably 10 to 30 parts by mass with respect to 50 to 90 parts by mass of the biodegradable polyester resin (A). If the blending amount of the spherical reinforcing material (C) is less than 5 parts by mass, it may not be possible to obtain a sufficient warp reduction effect or weld strength reduction suppression effect, which is not preferable. When the blending amount of the spherical reinforcing material (C) exceeds 45 parts by mass, the specific gravity of the mixture becomes too large and the mechanical strength is lowered, which is not preferable.

  The total amount of the fibrous reinforcing material (B) and the spherical reinforcing material (C) is preferably 10 to 50 parts by mass with respect to 50 to 90 parts by mass of the biodegradable polyester resin (A). Within such a range, the mechanical properties, heat resistance, warp reduction, and the effect of suppressing the weld strength reduction are excellent.

  The blending ratio (B) / (C) of the fibrous reinforcing material (B) and the spherical reinforcing material (C) is preferably 10 to 90/90 to 10 (parts by mass), and 20 to 80/80 to 20 More preferably, it is (parts by mass). When the blending ratio of the spherical reinforcing material is less than 10 parts by mass, it is not preferable because a sufficient warp reduction effect and a weld strength reduction suppressing effect cannot be obtained. If the blending ratio of the spherical reinforcing material exceeds 80 parts by mass, the mechanical strength decreases, which is not preferable.

  The method for adding the fibrous reinforcing material (B) and the spherical reinforcing material (C) used in the present invention is not particularly limited, but in the extruder, it is added from a hopper or using a side feeder. Can do. Further, by subjecting the fibrous reinforcing material (B) and the spherical reinforcing material (C) to a master batch process, the fibrous reinforcing material (B) can be diluted with a base resin during molding.

  In the resin composition of the present invention, pigments, heat stabilizers, antioxidants, end-capping agents, weathering agents, flame retardants, plasticizers, lubricants, mold release agents, antistatic agents, as long as the properties are not significantly impaired. Further, a filler, a crystal nucleus material and the like can be added. Examples of heat stabilizers and antioxidants include hindered phenols, phosphorus compounds, hindered amines, sulfur compounds, copper compounds, alkali metal halides, and the like. Examples of the terminal blocking agent include carbodiimide compounds, epoxy compounds, oxazoline compounds and the like. As the flame retardant, a halogen-based flame retardant, a phosphorus-based flame retardant, and an inorganic flame retardant can be used. However, in consideration of the environment, it is desirable to use a non-halogen flame retardant. Non-halogen flame retardants include phosphorus flame retardants, hydrated metal compounds (aluminum hydroxide, magnesium hydroxide, etc.), nitrogen-containing compounds (melamine-based, guanidine-based), inorganic compounds (borates, Mo compounds, etc.) Is mentioned. Inorganic fillers include talc, layered silicate, calcium carbonate, zinc carbonate, wollastonite, silica, alumina, magnesium oxide, calcium silicate, sodium aluminate, calcium aluminate, sodium aluminosilicate, magnesium silicate, glass balloon , Carbon black, zinc oxide, antimony trioxide, zeolite, hydrotalcite, metal fiber, metal whisker, ceramic whisker, potassium titanate, boron nitride, graphite, and the like. Examples of the organic filler include naturally occurring polymers such as starch, cellulose fine particles, wood flour, okara, fir shell, bran, and modified products thereof. Examples of the inorganic crystal core material include talc and kaolin. Examples of the organic crystal core material include a sorbitol compound, benzoic acid and a metal salt of the compound, a phosphate metal salt, and a rosin compound. In addition, the method of mixing these with the biodegradable polyester resin composition of this invention is not specifically limited.

  Further, the resin composition of the present invention includes polyamide (nylon), polyethylene, polypropylene, polybutadiene, polystyrene, AS resin, ABS resin, poly (acrylic acid), poly (acrylic acid) and poly (acrylic acid), as long as they do not depart from the spirit of the present invention. Non-biodegradable resins such as acrylic ester), poly (methacrylic acid), poly (methacrylic ester), polyethylene terephthalate, polyethylene naphthalate, polycarbonate, and copolymers thereof may be added.

  The resin composition of the present invention can be formed into various molded products by molding methods such as injection molding, blow molding, extrusion molding, inflation molding, and vacuum molding, pressure molding, and vacuum / pressure molding after sheet processing. In particular, an injection molding method is preferable, and in addition to a general injection molding method, gas injection molding, injection press molding, or the like can be employed. If an example of the injection molding conditions suitable for the resin composition of this invention is given, cylinder temperature will be Tm or flow start temperature more than biodegradable polyester resin (A), Preferably it is 130-280 degreeC, More preferably, it is 140-270. It is suitable to be in the range of ° C. If the cylinder temperature is too low, the operability becomes unstable, such as defective filling in the molded product, and overload tends to occur. Conversely, if the cylinder temperature is too high, the resin composition decomposes and the resulting molded product Problems such as reduction in strength and coloring are likely to occur.

  Moreover, the resin composition of this invention can improve the heat resistance by promoting crystallization. As a method for this purpose, for example, crystallization can be promoted by devising cooling conditions in the mold at the time of injection molding. In this case, the mold temperature is adjusted to biodegradable polyester resin (A It is preferable that the temperature is kept at (Tg + 20 ° C.) or more and (Tm−20 ° C.) or less for a predetermined time, and then cooled to Tg or less. Further, as a method for promoting crystallization after molding, it is preferable to directly heat the sample at Tg or more and (Tm−20 ° C.) or less after cooling to Tg or less.

  Specific examples of molded articles include resin parts for electrical appliances such as various cases, agricultural materials such as containers and cultivation containers, resin parts for agricultural machinery, resin parts for fishery business such as floats and processed fishery products containers, dishes, Tableware and food containers such as cups and spoons, medical resin parts such as syringes and infusion containers, drain materials, fences, storage boxes, resin parts for housing, civil engineering, and building materials such as construction switchboards, cooler boxes, fan fans, and toys Such as resin parts for miscellaneous goods, automobile parts such as bumpers, instrument panels and door trims. Moreover, it can also be set as extrusion molded articles, such as a film, a sheet | seat, and a pipe, and a hollow molded article.

EXAMPLES Hereinafter, although an Example demonstrates this invention further more concretely, this invention is not limited only to an Example. The measuring method used for evaluation of the resin composition of an Example and a comparative example is as follows.
(1) Bending strength, flexural modulus:
Measured according to ISO 178.
(2) Tensile strength, tensile modulus:
Measured according to ISO 527.
(3) Charpy impact strength:
Charpy impact strength was measured with a notched test piece in accordance with ISO 179.
(4) Deflection temperature under load (DTUL):
Based on ISO75, the heat distortion temperature was measured with a load of 0.45 MPa and a load of 1.8 MPa.
(5) Weld strength retention:
The tensile strength of a molded product obtained by pouring resin from both ends of a mold so that a weld portion is formed at the center of the ASTM D638-1 dumbbell piece is measured according to ASTM D638-1 dumbbell piece without a weld portion. The percentage divided by the value of tensile strength is shown as a percentage. The tensile test was performed according to ASTM D638.
(6) Sled height:
A disk-shaped test piece having a thickness of 1.6 mm and a diameter of 100 mm was injection-molded and held in an atmosphere of a temperature of 23 ° C. and a humidity of 50% RH for 24 hours, and then the warp height of the test piece was measured using a height gauge.
(7) Mold shrinkage:
A 20 mm square, 3 mm thick flat test piece is injection-molded and held in an atmosphere at a temperature of 23 ° C. and a humidity of 50% RH for 24 hours, and then using a high-precision two-dimensional dimension measuring instrument (manufactured by KEYENCE). The molding shrinkage ratio (%) in the flow direction (MD) and flow direction perpendicular to the flow (TD) of the resin during molding of the test piece was measured.
Further, a value (TD / MD value) obtained by dividing the molding shrinkage ratio of TD by the molding shrinkage ratio of MD was obtained as an index representing anisotropy. The closer this TD / MD value is to 1, the lower the anisotropy.

The raw materials used in Examples and Comparative Examples of the present invention are shown below.
・ Biodegradable polyester resin (A)
(1) Polylactic acid (PLA): manufactured by NatureWorks, weight average molecular weight (MW) = 190,000, melting point 166 ° C., melt flate (MFR) = 3 g / 10 minutes (2) polybutylene succinate (PBS): Mitsubishi Chemical company AZ-71TN, MW = 150,000, MFR = 14 g / 10 min. Fibrous reinforcement (B)
Glass fiber (GF): manufactured by Asahi Fiber Glass Co., Ltd., fiber diameter 10 μm, fiber length 3 mm, γ-glycidoxypropyltrimethoxysilane treated product, spherical reinforcing material (C)
Glass beads (GB): Potters Barotini EGB731, weight average particle size 20 μm
(Meth) acrylic acid ester compound (D):
Ethylene glycol dimethacrylate (EGDM): manufactured by NOF Corporation / peroxide di-t-butyl peroxide: manufactured by NOF Corporation

Example 1
Using a twin screw extruder (Ikegai PCM-30, die diameter 4 mm 3 holes, extrusion head temperature 210 ° C., die outlet temperature 190 ° C.), the top feeder port is PLA 70 parts by mass, the side feeder port is A product obtained by dry blending 20 parts by weight of glass fiber and 10 parts by weight of glass beads, and 0.2 parts by weight of EGDM and 0.4 parts by weight of peroxide using a pump from the middle of the kneading machine 1 A solution dissolved in parts by mass was supplied, extruded, and processed into a pellet to obtain a resin composition.
After the pellets were vacuum dried at 70 ° C. for 24 hours, test pieces for measuring physical properties were prepared using an IS-100E injection molding machine manufactured by Toshiba Machine Co., Ltd., and subjected to various measurements. Table 1 shows the molding conditions at this time.

Examples 2-6, Comparative Examples 1-9
A resin composition was obtained in the same manner as in Example 1 except that the biodegradable polyester resin, GF, GB, EGDM, and peroxide were changed to the types and amounts shown in Table 1, respectively. Physical properties were measured.

  Table 1 summarizes the evaluation results of Examples 1 to 6 and Comparative Examples 1 to 9.

As is apparent from Table 1, in Examples 1 to 6, the mechanical properties and heat resistance were excellent, the anisotropy of the molding shrinkage ratio was small, and the effect of suppressing warp generation and weld strength reduction was excellent. .
In Comparative Examples 1 to 5, since glass beads were not blended, the mechanical properties and heat resistance were excellent, but the anisotropy and warpage of the molding shrinkage ratio were large, and the weld strength retention was also low.
In Comparative Example 6, since the polylactic acid was not crosslinked, the heat resistance was poor.
In Comparative Examples 7-9, since glass fiber was not blended, the mechanical properties and heat resistance were poor.

Claims (7)

  The biodegradable polyester resin (A) is composed of 50 to 90 parts by mass, the fibrous reinforcing material (B) is 5 to 45 parts by mass, and the spherical reinforcing material (C) is 5 to 45 parts by mass. A resin composition, wherein A) is crosslinked with a (meth) acrylic acid ester compound (D).   The resin composition according to claim 1, wherein 0.01 to 10 parts by mass of the (meth) acrylic acid ester compound (D) is blended with respect to 100 parts by mass of the biodegradable polyester resin (A). .   The resin composition according to claim 1 or 2, wherein the biodegradable polyester resin (A) contains a polylactic acid resin as a main component.   The resin composition according to any one of claims 1 to 3, wherein the fibrous reinforcing material (B) is a glass fiber.   The resin composition according to any one of claims 1 to 4, wherein the spherical reinforcing material (C) is a glass bead.   The (meth) acrylic acid ester compound (D) has two or more (meth) acryl groups in the molecule, or one or more (meth) acryl groups and one or more glycidyl groups or vinyl groups. It is a compound, The resin composition in any one of Claims 1-5 characterized by the above-mentioned. The molded object which consists of a resin composition in any one of Claims 1-6.