JP2006056987A - Aliphatic polyester resin composition and molded product using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aliphatic polyester resin composition having excellent impact resistance and thermal stability, and also having excellent heat resistance; and to provide a molded product comprising the composition. <P>SOLUTION: The aliphatic polyester resin composition contains (A) an aliphatic polyester and (B) a graft copolymer obtained by grafting a vinylic monomer containing an alkyl acrylate and/or an aromatic vinyl monomer on an acrylic rubber and/or a silicone-acrylic rubber. A polylactic acid is preferably used as the aliphatic polyester. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an aliphatic polyester resin composition excellent in impact resistance and thermal stability, an aliphatic polyester resin composition excellent in heat resistance, and a molded article comprising the same.

  Recently, biodegradable polymers that are decomposed in the natural environment by the action of microorganisms existing in the soil and water have attracted attention from the viewpoint of global environmental conservation, and various biodegradable polymers have been developed. Among these, as a biodegradable polymer that can be melt-molded, for example, polyethylene comprising an aliphatic dicarboxylic acid component such as polyhydroxybutyrate, polycaprolactone, succinic acid or adipic acid and a glycol component such as ethylene glycol or butanediol. Aliphatic polyesters such as succinate, polybutylene adipate and polylactic acid are known.

  Among aliphatic polyesters, polylactic acid is relatively inexpensive and has a high melting point of about 170 ° C., and is expected as a biodegradable polymer that can be melt-molded. In addition, lactic acid, which is a monomer, has recently been manufactured at low cost by fermentation using microorganisms, and it has become possible to produce polylactic acid at a much lower cost, so that not only as a biodegradable polymer, Use as a general-purpose polymer has also been studied. However, on the other hand, it has physical defects such as low impact resistance and low flexibility, and an improvement is desired.

  In general, in order to improve the impact resistance of a resin, it is known to blend a rubbery polymer such as an olefin copolymer, and a method of adding a modified olefin compound to polylactic acid (for example, Patent Document 1). However, in these methods, the impact resistance improving effect is insufficient and further improvement is required.

  In addition, since the polylactic acid resin has a glass transition temperature of 60 ° C. and the temperature is higher than that, the rigidity is drastically lowered. Therefore, when used as a molded product, thermal deformation at a high temperature of 60 ° C. or more becomes large. There is also a problem that blending rubber-like polymers further increases thermal deformation and reduces heat resistance, which is not practical.

JP 9-316310 A JP 2001-123055 A

  The present invention has been achieved as a result of studying the solution of the above-described problems in the prior art as an object, and the object thereof is an aliphatic polyester resin composition excellent in impact resistance and thermal stability, Furthermore, it is providing the aliphatic polyester resin composition excellent also in heat resistance, and a molded article consisting thereof.

  The gist of the present invention is that (A) an aliphatic polyester and (B) an acrylic rubber and / or a silicone acrylic rubber are grafted with a vinyl monomer containing an alkyl acrylate ester and / or an aromatic vinyl monomer. And an aliphatic polyester resin composition containing the graft copolymer.

  According to the resin composition of the present invention, it is possible to provide an aliphatic polyester resin composition excellent in impact resistance, thermal stability and heat resistance, and a molded article comprising the same.

The (A) aliphatic polyester used in the present invention is not particularly limited, and a polymer mainly composed of an aliphatic hydroxycarboxylic acid, a main structure composed of an aliphatic polycarboxylic acid and an aliphatic polyhydric alcohol. Examples include polymers as components. Specifically, polymers having aliphatic hydroxycarboxylic acid as a main component include polyglycolic acid, polylactic acid, poly-3-hydroxybutyric acid, poly-4-hydroxybutyric acid, poly-4-hydroxyvaleric acid, poly-3- Hydroxyhexanoic acid or polycaprolactone, etc., and examples of the polymer mainly composed of aliphatic polycarboxylic acid and aliphatic polyhydric alcohol include polyethylene adipate, polyethylene succinate, polybutylene adipate, or polybutylene succinate. Is mentioned. These aliphatic polyesters can be used alone or in combination of two or more. Among these aliphatic polyesters, a polymer containing hydroxycarboxylic acid as a main constituent is preferable, and polylactic acid is particularly preferably used.
The polylactic acid is a polymer mainly composed of L-lactic acid and / or D-lactic acid, but may contain other copolymer components other than lactic acid as long as the object of the present invention is not impaired. .

  Examples of such other copolymer component units include polyvalent carboxylic acids, polyhydric alcohols, hydroxycarboxylic acids, lactones, and the like. Specifically, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid , Azelaic acid, sebacic acid, dodecanedioic acid, fumaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium sulfoisophthalic acid Polyhydric carboxylic acids such as ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerin, trimethyl Propanediol, pentaerythritol, bisphenol A, aromatic polyhydric alcohols obtained by addition reaction of ethylene oxide with bisphenol, polyhydric alcohols such as diethylene glycol, triethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, glycolic acid, Hydroxycarboxylic acids such as 3-hydroxybutyric acid, 4-hydroxybutyric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, hydroxybenzoic acid, glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ- Lactones such as butyrolactone, β- or γ-butyrolactone, pivalolactone, and δ-valerolactone can be used. These copolymer components can be used alone or in combination of two or more.

  In order to obtain high heat resistance with polylactic acid, it is preferable that the optical purity of the lactic acid component is high. Among the total lactic acid components, L-form or D-form is preferably contained at 80 mol% or more, and more preferably 90 mol%. It is preferably contained in an amount of 95 mol% or more.

  (A) As a manufacturing method of aliphatic polyester, a known polymerization method can be used. In particular, for polylactic acid, a direct polymerization method from lactic acid, a ring-opening polymerization method via lactide, or the like can be employed.

  (A) The molecular weight or molecular weight distribution of the aliphatic polyester is not particularly limited as long as it can be substantially molded, and the mass average molecular weight is preferably 10,000 or more, more preferably 40,000 or more. Particularly preferably, it should be 80,000 or more. The mass average molecular weight here is a mass average molecular weight in terms of polymethyl methacrylate (PMMA) measured by gel permeation chromatography (GPC) using hexafluoroisopropanol as a solvent.

  (A) Melting | fusing point of aliphatic polyester is not specifically limited, It is preferable that it is 90 degreeC or more, and it is more preferable that it is 150 degreeC or more.

  In the present invention, (B) a graft copolymer obtained by grafting an acrylic rubber and / or a silicone acrylic rubber with a vinyl monomer containing an alkyl acrylate and / or an aromatic vinyl monomer. use.

  The acrylic rubber can be synthesized using the following alkyl (meth) acrylate, a crosslinking agent and a graft crossing agent. Examples of the alkyl (meth) acrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and alkyl methacrylates such as hexyl methacrylate, 2-ethylhexyl methacrylate, and n-lauryl methacrylate. In particular, the use of 2-ethylhexyl acrylate and n-butyl acrylate is preferable.

  Examples of the crosslinking agent include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, and the like.

  Examples of the graft crossing agent include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate and the like. Allyl methacrylate can also be used as a crosslinking agent. These crosslinking agents and graft crossing agents may be used alone or in combination of two or more. The total amount of these crosslinking agents and grafting agents is 0.01 to 20% by mass in the polyalkyl (meth) acrylate component.

  The silicone acrylic rubber is preferably a polyorganosiloxane / acrylic composite rubber containing a polyorganosiloxane and an alkyl (meth) acrylate rubber. The composite rubber may be produced by any method, but the emulsion polymerization method is optimal.

  The polyorganosiloxane / acrylic composite rubber containing the polyorganosiloxane and the alkyl (meth) acrylate rubber described above has a polyorganosiloxane component of 0.1 to 99.9% by mass and an alkyl (meth) acrylate rubber component of 99. It is preferable that it is in the range of .9 to 0.1% by mass (the total amount of both components is 100% by mass). The polyorganosiloxane / acrylic composite rubber may be produced by any method, but the latex of the polyorganosiloxane is first prepared by emulsion polymerization, and then the monomer constituting the alkyl (meth) acrylate rubber is polymerized. It is preferred that the organosiloxane latex particles are impregnated and then polymerized.

  The polyorganosiloxane rubber component constituting the composite rubber can be prepared by emulsion polymerization using the following organosiloxane and, if necessary, a crosslinking agent. In that case, a graft crossing agent can also be used together. Examples of the organosiloxane include various cyclic members having a 3-membered ring or more, and a 3- to 6-membered ring is preferably used. Examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, and the like. These may be used alone or in combination of two or more. The amount of these used is 50% by mass or more, preferably 70% by mass or more in the polyorganosiloxane component.

  As the crosslinking agent, trifunctional or tetrafunctional silane-based crosslinking agents such as trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetrabutoxysilane are used. It is done. In particular, tetrafunctional crosslinking agents are preferred, and tetraethoxysilane is particularly preferred among these. The usage-amount of a crosslinking agent is 0-20 mass% in a polyorganosiloxane component.

As the graft crossing agent, a compound capable of forming a unit represented by the following formula is used.
^{_{CH 2 = C (R 2)}} -COO- (CH 2) p-SiR 1 n O (3-n) / 2 (GI-1)
_{^{CH 2 = C (R 2)}} -C 6 H 4 -SiR 1 n O (3-n) / 2 (GI-2)
_{^{CH 2 = CH-SiR 1 n}} O (3-n) / 2 (GI-3)
_{^{HS- (CH 2) p-SiR}} 1 n O (3-n) / 2 (GI-4)
(Wherein R1 is a methyl group, an ethyl group, a propyl group, or a phenyl group, R2 is a hydrogen atom or a methyl group, n is 0, 1 or 2, and p is a number from 1 to 6). (Meth) acryloyloxysiloxane capable of forming a unit of GI-1) is capable of forming an effective graft chain because of its high grafting efficiency, and is advantageous in terms of impact resistance.

  In addition, methacryloyloxysiloxane is particularly preferable as the unit capable of forming the unit of the above formula (GI-1). Specific examples of methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropyl. Examples include ethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, and γ-methacryloyloxybutyldiethoxymethylsilane. A vinyl siloxane is mentioned as what can form the unit of the said formula (GI-2), As a specific example, a tetramethyltetravinylcyclotetrasiloxane is mentioned. As what can form the unit of the said formula (GI-3), p-vinylphenyl dimethoxymethylsilane is mentioned. Moreover, (gamma) -mercaptopropyl dimethoxymethylsilane, (gamma) -mercaptopropyl methoxydimethylsilane, (gamma) -mercaptopropyl diethoxymethylsilane etc. are mentioned as what can form the unit of a formula (GI-4). The amount of the grafting agent used is 0.01 to 20% by mass, preferably 0.05 to 10% by mass in the polyorganosiloxane component.

  The polyorganosiloxane component latex can be produced by a method described in, for example, US Pat. Nos. 2,891,920 and 3,294,725. In the practice of the present invention, for example, a mixed solution of an organosiloxane, a crosslinking agent, and a graft crossing agent is sheared and mixed with water in the presence of a sulfonic acid-based emulsifier such as alkylbenzenesulfonic acid or alkylsulfonic acid, for example, using a homogenizer. It is preferable to manufacture by the method to do. Alkylbenzenesulfonic acid is suitable because it acts as an emulsifier for organosiloxane and at the same time serves as a polymerization initiator. In this case, it is preferable to use an alkylbenzene sulfonic acid metal salt, an alkyl sulfonic acid metal salt, or the like in combination because it has an effect of maintaining a stable polymer during graft polymerization.

  Next, the alkyl (meth) acrylate rubber component constituting the composite rubber can be synthesized using the following alkyl (meth) acrylate, a crosslinking agent, and a graft crossing agent. Examples of the alkyl (meth) acrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate, and alkyl methacrylates such as hexyl methacrylate, 2-ethylhexyl methacrylate, and n-lauryl methacrylate. In particular, the use of 2-ethylhexyl acrylate and n-butyl acrylate is preferable.

  Examples of the crosslinking agent include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, and the like. Examples of the graft crossing agent include allyl methacrylate, triallyl cyanurate, triallyl isocyanurate and the like. Allyl methacrylate can also be used as a crosslinking agent. These crosslinking agents and graft crossing agents may be used alone or in combination of two or more. The total amount of these crosslinking agents and grafting agents is 0.1 to 20% by mass in the polyalkyl (meth) acrylate component.

  The polymerization of the alkyl (meth) acrylate rubber component is carried out by adding the above alkyl (meth) acrylate and crosslinking agent into the latex of the polyorganosiloxane component neutralized by the addition of an aqueous alkali solution such as sodium hydroxide, potassium hydroxide or sodium carbonate. Further, after adding a graft crossing agent and impregnating the polyorganosiloxane particles, a normal radical polymerization initiator is allowed to act. As the polymerization proceeds, a latex of a composite rubber of a polyorganosiloxane component and a polyalkyl (meth) acrylate component is obtained. In carrying out the present invention, as the composite rubber, the main skeleton of the polyorganosiloxane rubber component has a repeating unit of dimethylsiloxane, and the main skeleton of a polyalkyl (meth) acrylate component has a repeating unit of n-butyl acrylate. Composite rubber is preferably used. The composite rubber thus prepared by emulsion polymerization can be graft copolymerized with a vinyl monomer, and the gel content measured by extraction with toluene at 90 ° C. for 4 hours should be 50% by mass or more. preferable.

In the graft copolymer (B) used in the present invention, a vinyl monomer containing an acrylic acid alkyl ester and / or an aromatic vinyl monomer is graft-polymerized on the above-mentioned acrylic rubber and / or silicone acrylic rubber. Is obtained.
In the present invention, the alkyl acrylate monomer used for graft polymerization is not particularly limited, but ethyl acrylate and n-butyl acrylate are preferably used. The aromatic vinyl monomer is not particularly limited, but styrene, α-methylstyrene, various halogen-substituted and alkyl-substituted styrenes are preferably used.

  The amount of the monomer or monomer mixture used for the graft polymerization is not particularly limited, but is 50 to 5% by mass with respect to 50 to 95% by mass of the acrylic rubber and / or silicone acrylic rubber polymer. Is preferred. When the amount of the monomer or monomer mixture used in the graft polymerization exceeds 50% by mass, the impact resistance improving effect may be lowered. When the amount is less than 5% by mass, the graft copolymer (B) Powder properties may be degraded.

  The alkyl acrylate and / or aromatic vinyl used in the graft part is preferably contained in an amount of 0.1 to 50% by mass with the entire graft part as 100%, and more preferably contained in a part of the outermost layer. .

  If the alkyl acrylate and / or aromatic vinyl is 0.1% by mass or less, the effects of the present invention, the thermal stability and impact resistance, may not be sufficiently exhibited, and if 50% by mass or more, the aliphatic polyester resin and Compatibility may be reduced, and physical properties such as impact resistance may be reduced. A more preferable content is 1 to 40% by mass.

  The graft copolymer used in the present invention is obtained by adding a vinyl monomer to a rubber polymer latex and polymerizing it in one or more stages by radical polymerization technology, and salting out and coagulating the obtained graft copolymer latex. Can be obtained by separation and recovery, or by direct recovery by a spray drying method or the like. As the coagulant, a metal compound is preferably used, and in particular, an alkaline earth metal salt compound such as magnesium sulfate, calcium acetate, calcium chloride, or the like is preferably used. Among them, although there is no particular limitation, in the present invention, it is more preferable to use calcium acetate from the viewpoint of thermal stability. In graft polymerization, a component corresponding to a branch of the graft copolymer is polymerized with only the branch component without grafting to the trunk component, and a free polymer is also partially produced as a mixture of the graft copolymer and the free polymer. Although obtained, in the present invention, these are collectively referred to as a graft copolymer.

  The (B) acrylic rubber-based and / or silicone acrylic rubber-based graft copolymer of the present invention may further contain a carboxyl group-containing copolymer in order to improve impact resistance. As the carboxylic acid group-containing copolymer, a mixture comprising an alkyl acrylate and at least one unsaturated acid monomer copolymerizable with the alkyl acrylate is used in the presence of at least one anionic surfactant. Latex having a pH of 4 or higher obtained by polymerization is preferably used. In addition, as for carbon number of an alkyl group, 1-12 are preferable.

  The alkyl acrylate is preferably 70% by mass or more and 99% by mass or less, and the unsaturated acid monomer is preferably 1% by mass or more and 30% by mass or less. When the unsaturated acid monomer is less than 1% by mass, the effect of improving the impact strength may not appear.

  Examples of the alkyl acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, and lauryl acrylate.

  As the unsaturated acid monomer, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, cinnamic acid, maleic anhydride, butenetricarboxylic acid and the like can be used.

  Also, other monomers can be copolymerized. As such a monomer, for example, one or more selected from styrene, methyl methacrylate, acrylonitrile, butadiene and the like can be used.

  The addition amount of the carboxyl group-containing copolymer is not particularly limited, but is preferably 0.01% by mass or more as a solid content with respect to 100% by mass of the acrylic rubber-based and / or silicone acrylic rubber-based graft copolymer. In order to avoid damage to other properties, the solid content is preferably 10 parts by mass or less.

As the graft polymerization method, an emulsion polymerization method is used. Although superposition | polymerization temperature is based also on the kind of polymerization initiator, it can carry out suitably in the range of about 40-80 degreeC. As the emulsifier, a known emulsifier can be appropriately used.
it can.

  The primary particle diameter of the (B) acrylic rubber-based and / or silicone acrylic rubber-based graft copolymer in the present invention is not particularly limited, but is preferably 0.01 μm or more and 1000 μm or less. More preferably, the thickness is from 0.05 μm to 2 μm, and most preferably from 0.1 μm to 1 μm.

  In the present invention, the mass ratio of (A) aliphatic polyester and (B) acrylic rubber-based and / or silicone acrylic rubber-based graft copolymer is not particularly limited, but is 99/1 to 50/50. More preferably, it is more preferably 99/1 to 60/40, and most preferably 99/1 to 70/30.

  In the present invention, (B) acrylic rubber and / or silicone acrylic rubber graft copolymer is finely dispersed in (A) aliphatic polyester, and the better the dispersion, the greater the effect of improving impact resistance. .

  In the present invention, it is preferable to further contain a crystal nucleating agent from the viewpoint of improving heat resistance.

  As the crystal nucleating agent to be used in the present invention, those generally used as a polymer crystal nucleating agent can be used without particular limitation, and any of an inorganic crystal nucleating agent and an organic crystal nucleating agent can be used. it can.

  Specific examples of inorganic crystal nucleating agents include talc, kaolinite, montmorillonite, mica, synthetic mica, clay, zeolite, silica, graphite, carbon black, zinc oxide, magnesium oxide, calcium oxide, titanium oxide, calcium sulfide, and nitriding. Examples thereof include metal salts of boron, magnesium carbonate, calcium carbonate, barium sulfate, aluminum oxide, neodymium oxide, and phenylphosphonate, and talc, kaolinite, montmorillonite, and synthetic mica are preferable from the viewpoint of a large effect of improving heat resistance. . These may be used alone or in combination of two or more. These inorganic crystal nucleating agents are preferably modified with an organic substance in order to enhance dispersibility in the composition.

  The content of the inorganic crystal nucleating agent is preferably 0.01 to 100 parts by mass, more preferably 0.05 to 50 parts by mass with respect to 100 parts by mass of the (A) aliphatic polyester resin, and 0.1 to 30 Part by mass is more preferable.

  Specific examples of organic crystal nucleating agents include sodium benzoate, potassium benzoate, lithium benzoate, calcium benzoate, magnesium benzoate, barium benzoate, lithium terephthalate, sodium terephthalate, potassium terephthalate, Calcium oxide, 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, salicylic acid , Metal salts of organic carboxylic acids such as aluminum dibenzoate, potassium dibenzoate, lithium dibenzoate, sodium β-naphthalate, sodium cyclohexanecarboxylate, organic sulfonates such as sodium p-toluenesulfonate, sodium sulfoisophthalate, stearic acid Amide, ethylenebislauric acid amide, palmitic acid amide, hydroxystearic acid amide, erucic acid amide, carboxylic acid amides such as trimesic acid tris (t-butylamide), low density polyethylene, high density polyethylene, polypropylene, polyisopropylene, polybutene Polymers such as poly-4-methylpentene, poly-3-methylbutene-1, polyvinylcycloalkane, polyvinyltrialkylsilane, and high melting point polylactic acid, Sodium salt or potassium salt of a polymer having a carboxyl group such as sodium salt of ethylene-acrylic acid or methacrylic acid copolymer, sodium salt of styrene-maleic anhydride copolymer (so-called ionomer), benzylidene sorbitol and its derivatives, sodium-2, Phosphorus compound metal salts such as 2'-methylenebis (4,6-di-t-butylphenyl) phosphate and sodium 2,2-methylbis (4,6-di-t-butylphenyl) From the viewpoint that the effect of improving the resistance is large, organic carboxylic acid metal salts and carboxylic acid amides are preferred. These may be used alone or in combination of two or more.

  The content of the organic crystal nucleating agent is preferably 0.01 to 30 parts by mass, more preferably 0.05 to 10 parts by mass with respect to 100 parts by mass of the (A) aliphatic polyester resin, and 0.1 to 5 parts. Part by mass is more preferable.

  In this invention, it is preferable to contain fillers other than an inorganic crystal nucleating agent from a viewpoint that heat resistance improves.

  As fillers other than the inorganic crystal nucleating agent used in the present invention, fibrous, plate-like, granular, and powdery materials that are usually used for reinforcing thermoplastic resins can be used. Specifically, glass fiber, asbestos fiber, carbon fiber, graphite fiber, metal fiber, potassium titanate whisker, aluminum borate whisker, magnesium whisker, silicon whisker, wollastonite, sepiolite, asbestos, slag fiber, zonolite , Elastadite, gypsum fiber, silica fiber, silica-alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber and boron fiber, etc., inorganic fiber filler, polyester fiber, nylon fiber, acrylic fiber, regenerated cellulose fiber, acetate fiber Organic fiber fillers such as kenaf, ramie, cotton, jute, hemp, sisal, flax, linen, silk, manila hemp, sugar cane, wood pulp, paper waste, waste paper and wool, glass flakes, graphite, metal foil, ceramic beads Sericite, bentonite, dolomite, fine silicic acid, feldspar powder, potassium titanate, shirasu balloon, aluminum silicate, silicon oxide, gypsum, novaculite, include plate-like or particulate filler, such as such as dawsonite and white clay. Among these fillers, inorganic fibrous fillers are preferable, and glass fibers and wollastonite are particularly preferable. Moreover, use of an organic fibrous filler is also preferable, and natural fiber and regenerated fiber are more preferable from the viewpoint of taking advantage of biodegradability of the aliphatic polyester resin. Further, the aspect ratio (average fiber length / average fiber diameter) of the fibrous filler used for blending is preferably 5 or more, more preferably 10 or more, and further preferably 20 or more. The filler may be coated or focused with a thermoplastic resin such as an ethylene / vinyl acetate copolymer or a thermosetting resin such as an epoxy resin, or may be a coupling agent such as aminosilane or epoxysilane. It may be processed.

  0.1-200 mass parts is preferable with respect to 100 mass parts of (A) aliphatic polyester resin, and, as for content of a filler, 0.5-100 mass parts is more preferable.

  In the present invention, it is preferable to further contain a plasticizer from the viewpoint of improving heat resistance.

  As the plasticizer used in the present invention, those generally used as polymer plasticizers can be used without particular limitation. For example, polyester plasticizer, glycerin plasticizer, polyvalent carboxylic ester plasticizer, polyalkylene Examples include glycol plasticizers and epoxy plasticizers.

  Specific examples of the polyester plasticizer include acid components such as adipic acid, sebacic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, propylene glycol, 1,3-butanediol, 1,4-butane. Examples thereof include polyesters composed of diol components such as diol, 1,6-hexanediol, ethylene glycol and diethylene glycol, and polyesters composed of hydroxycarboxylic acid such as polycaprolactone. These polyesters may be end-capped with a monofunctional carboxylic acid or monofunctional alcohol, or may be end-capped with an epoxy compound or the like.

  Specific examples of the glycerin plasticizer include glycerin monoacetomonolaurate, glycerin diacetomonolaurate, glycerin monoacetomonostearate, glycerin diacetomonooleate, and glycerin monoacetomonomontanate.

  Specific examples of polycarboxylic acid plasticizers include phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, diheptyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, and trimellitic acid. Trimellitic acid esters such as tributyl, trioctyl trimellitic acid, trihexyl trimellitic acid, sebacic acid esters such as diisodecyl adipate, n-octyl-n-decyl adipate adipate, triethyl acetylcitrate, tributyl acetylcitrate, etc. Citrate esters, azelaic acid esters such as di-2-ethylhexyl azelate, sebacic acid esters such as dibutyl sebacate, and di-2-ethylhexyl sebacate.

  Specific examples of the polyalkylene glycol plasticizer include polyethylene glycol, polypropylene glycol, poly (ethylene oxide / propylene oxide) block and / or random copolymer, polytetramethylene glycol, ethylene oxide addition polymer of bisphenols, bisphenols Polyalkylene glycols such as propylene oxide addition polymers, tetrahydrofuran addition polymers of bisphenols, or end-capped compounds such as terminal epoxy-modified compounds, terminal ester-modified compounds, and terminal ether-modified compounds.

  The epoxy plasticizer generally refers to an epoxy triglyceride composed of an alkyl epoxy stearate and soybean oil, but there are also so-called epoxy resins mainly made of bisphenol A and epichlorohydrin. Can be used.

  Specific examples of other plasticizers include benzoic acid esters of aliphatic polyols such as neopentyl glycol dibenzoate, diethylene glycol dibenzoate, triethylene glycol di-2-ethylbutyrate, fatty acid amides such as stearamide, oleic acid Examples thereof include aliphatic carboxylic acid esters such as butyl, oxyacid esters such as methyl acetylricinoleate and butyl acetylricinoleate, pentaerythritol, various sorbitols, polyacrylic acid esters, silicone oils, and paraffins.

  Among the plasticizers used in the present invention, at least one selected from polyester plasticizers and polyalkylene glycol plasticizers is particularly preferable. The plasticizer used in the present invention may be used alone or in combination of two or more.

  Moreover, the range of 0.01-30 mass parts is preferable with respect to 100 mass parts of (A) aliphatic polyester resin, and, as for content of a plasticizer, the range of 0.1-20 mass parts is more preferable. A range of 5 to 10 parts by mass is more preferable.

  In the present invention, each of the crystal nucleating agent and the plasticizer may be used alone, but it is preferable to use both in combination.

  In the present invention, stabilizers (antioxidants, ultraviolet absorbers, etc.), lubricants, mold release agents, flame retardants, colorants including dyes or pigments, antistatic agents, etc. are added within a range not impairing the object of the present invention. be able to.

  In the present invention, other thermoplastic resins (for example, polyethylene, polypropylene, acrylic resin, polyamide, polyphenylene sulfide resin, polyether ether ketone resin, polyester, polysulfone, polyphenylene oxide, polyacetal, polyimide are used within the range not impairing the object of the present invention. , Polyetherimide, etc.) or thermosetting resin (eg phenol resin, melamine resin, polyester resin, silicone resin, epoxy resin etc.) or soft thermoplastic resin (eg ethylene / glycidyl methacrylate copolymer, polyester elastomer, polyamide elastomer, Ethylene / propylene terpolymer, ethylene / butene-1 copolymer, etc.) and the like.

  The method for producing the aliphatic polyester resin composition of the present invention is not particularly limited. For example, (A) aliphatic polyester, (B) acrylic rubber-based and / or silicone acrylic rubber-based graft copolymer, crystal nucleus After pre-blending agents, fillers, plasticizers and other additives as necessary, melt and knead uniformly with a single or twin screw extruder above the melting point or remove the solvent after mixing in solution A method or the like is preferably used.

In the present invention, the obtained composition can be molded by any method such as generally known injection molding or extrusion molding, and can be widely used as a molded product of any shape. Molded products are films, sheets, fibers / clothes, non-woven fabrics, injection molded products, extrusion molded products, vacuum / pressure molded products, blow molded products, or composites with other materials. It is useful for electronic equipment materials, agricultural materials, horticultural materials, fishery materials, civil engineering / architectural materials, stationery, medical supplies or other uses.

The following examples illustrate the invention.
Various evaluations and moldings were performed by the following methods.
(1) Extruder A compound in the present invention, such as an aliphatic polyester resin, was melt-kneaded using a twin screw extruder of φ30 mm and L / D = 28 to obtain thermoplastic resin composition pellets.
(2) Injection molding machine Using the thermoplastic resin composition pellets, Charpy impact strength evaluation specimens were molded by an injection molding method.
(3) Izod impact strength (initial impact value)
The Izod impact strength at 23 ° C. and 0 ° C. was evaluated according to ASTM D256.
(4) Impact value after retention After the molten resin was forcibly retained for 20 minutes in the cylinder of the molding machine, the molded product obtained by injecting the molten resin was measured by ASTM D256 at Izod impact strength.
(5) Impact value retention rate The impact value retention rate (%) was determined by the following formula. The higher the impact value retention rate, the better the thermal stability.
(Shock value retention) (%) = [(Shock value after staying) / (Initial impact value)] × 100
(6) Heat resistance According to ASTM D648, the heat deformation temperature (load 0.45 MPa) of a test piece of 12.7 mm × 6.4 mm × 127 mm was measured.
(7) Measurement of mass average particle diameter of latex Using the obtained latex diluted with distilled water as a sample, the latex was measured using a CHDF2000 type particle size distribution meter manufactured by MATEC USA. The measurement conditions were standard conditions recommended by MATEC. Using a special particle separation capillary cartridge and carrier liquid, diluted latex sample 0 with a concentration of 3% with neutrality of liquidity, flow rate of 1.4 mL / min, pressure of 28 MPa and temperature of 35 ° C. 1 mL was used for the measurement. As the standard particle size substance, a total of 12 monodisperse polystyrenes having a known particle size manufactured by DUKE Co., Ltd. in the United States were used in the range of 0.03 μm to 0.8 μm.

Production Example 1 Production of Polyorganosiloxane / Acrylic Composite Rubber Graft Copolymer (B-1) 2 parts of tetraethoxysilane, 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and octamethylcyclotetrasiloxane 97. 5 parts were mixed to obtain 100 parts of a siloxane mixture. 100 parts of a siloxane mixture is added to 200 parts of distilled water in which 0.67 parts of sodium dodecylbenzenesulfonate and 0.67 parts of dodecylbenzenesulfonic acid are dissolved, and the mixture is pre-stirred at 10,000 rpm with a homomixer, and then 200 kg / cm with a homogenizer. ^The mixture was emulsified and dispersed at a pressure of ² to obtain an organosiloxane emulsion. This was transferred to a separable flask equipped with a condenser and a stirring blade, heated at 80 ° C. for 5 hours with mixing and stirring, then allowed to stand at 20 ° C., and after 48 hours, the pH of the emulsion was adjusted to 7.0 with an aqueous sodium hydroxide solution. Thus, the polymerization was completed to obtain a latex containing polyorganosiloxane. The polymerization rate of the obtained polyorganosiloxane was 89.1%, and the average particle size of the polyorganosiloxane was 0.19 μm.

  8.0 parts of this polyorganosiloxane-containing latex is sampled as a solid, put into a separable flask equipped with a stirrer, added with 208 parts of distilled water, purged with nitrogen, heated to 50 ° C., and n -A mixture of 70.5 parts of butyl acrylate, 1.5 parts of allyl methacrylate and 0.3 part of tert-butyl hydroperoxide was charged and stirred for 30 minutes to allow the mixture to penetrate the polyorganosiloxane. Next, a mixture of 0.003 part of ferrous sulfate, 0.003 part of ethylenediaminetetraacetic acid disodium salt, 0.24 part of Rongalite and 10 parts of distilled water was charged to start radical polymerization. The polymerization was completed by holding for a time to obtain a latex of a polyorganosiloxane composite rubber. A part of this latex was sampled and the average particle size of the polyorganosiloxane composite rubber was measured and found to be 0.22 μm.

  Into the latex containing the polyorganosiloxane composite rubber, a mixture of 17.0 parts of methyl methacrylate, 3.0 parts of n-butyl acrylate and 0.13 parts of tert-butyl hydroperoxide was dropped at 60 ° C. over 50 minutes. Then, it was kept at 60 ° C. for 1 hour to complete the graft polymerization onto the polyorganosiloxane composite rubber. The average particle size of the graft copolymer (M-1) was 0.27 μm. To 200 parts of an aqueous solution containing 1.5 parts of calcium acetate at 50 ° C., 100 parts of latex (about 30% as a solid content) containing the obtained graft copolymer (B-1) was added, and then 90 After solidifying by heating to 0 ° C. and repeating washing with water, the solid content was separated and dried at 80 ° C. for 24 hours to obtain a graft polymer (B-1) powder.

Production Example 2 Production of Polyorganosiloxane / Acrylic Composite Rubber Graft Copolymer (B-2) The same method except that 3 parts of n-butyl acrylate used for graft polymerization in Production Example 1 was changed to 3 parts of styrene. A composite rubber graft copolymer (B-2) was obtained.

(Production Example 3) Production of polyorganosiloxane / acrylic composite rubber graft copolymer (B-3) The same as in Production Example 1 except that 3 parts of n-butyl acrylate used for graft polymerization was changed to 3 parts of methyl methacrylate. By the method, a composite rubber graft copolymer (B-3) was obtained.

(Production Examples 4 to 6) Production of polyorganosiloxane / acrylic composite rubber graft copolymers (B-4) to (B-6) Same as Production Example 1 except that the composition was changed as shown in Table 1. By the method, composite rubber graft copolymers (B-4) to (B-6) were obtained.

(Production Examples 7 and 8) Production of polyorganosiloxane / acrylic composite rubber graft copolymers (B-7) and (B-8) The coagulant used for powder recovery was calcium chloride and 5% aluminum sulfate aqueous solution, respectively. Except for the changes, composite rubber graft copolymers (B-7) to (B-8) were obtained in the same manner as in Production Example 1.

(Production Example 9) Production of polyorganosiloxane / acrylic composite rubber graft copolymer (B-9) In Production Example 1, a carboxyl group-containing copolymer (n-butyl acrylate / methacrylic acid = 85) after composite rubber polymerization. A composite rubber graft copolymer (B-9) was obtained in the same manner except that 2 parts by mass of / 15) was added as a solid content.

(Production Example 10) Production of acrylic rubber-based graft copolymer (B-10) 99.5 parts of 2-ethylhexyl acrylate and 0.5 parts of allyl methacrylate were mixed to obtain 100 parts of a (meth) acrylate monomer mixture. It was. As alkyl diphenyl ether disulfonate sodium, 100 parts of the above (meth) acrylate monomer mixture is added to 195 parts of distilled water in which 1.9 parts of the registered trademark Perex SS-L commercially available from Kao Corporation is dissolved. After pre-stirring at 10,000 rpm with a homomixer, the mixture was emulsified and dispersed with a homogenizer at a pressure of 300 kg / cm ² to obtain a (meth) acrylate emulsion. This mixed solution was transferred to a separable flask equipped with a condenser and a stirring blade, heated with nitrogen substitution and mixed stirring, and when the temperature reached 50 ° C, 0.5 part of tert-butyl hydroperoxide was added, and the temperature was raised to 50 ° C. Then, a mixed solution of 0.002 part of ferrous sulfate, 0.006 part of disodium ethylenediaminetetraacetate, 0.26 part of Rongalite and 5 parts of distilled water was added and left for 5 hours to complete the polymerization and acrylic rubber. (A-1) Component latex was obtained. The polymerization rate of the obtained acrylic rubber (a-1) component latex was 99.9%. Furthermore, 3.0 parts of PELEX SS-L as a solid content was added to the obtained latex.

The acrylic rubber (a-1) component latex is sampled to 20 parts as the solid content of poly-2-ethylhexyl acrylate containing allyl methacrylate, placed in a separable flask equipped with a stirrer, and the amount of distilled water in the system is Added to 195 parts. Next, a mixed solution of 69 parts of n-butyl acrylate containing 2.0% of allyl methacrylate constituting the acrylic rubber (a-2) component and 0.32 part of tert-butyl hydroperoxide was charged and stirred for 10 minutes. The liquid was infiltrated into the acrylic rubber (a-1) component particles. After stirring for another 10 minutes, the atmosphere was replaced with nitrogen, the temperature in the system was raised to 50 ° C., 0.001 part of ferrous sulfate, 0.003 part of disodium ethylenediaminetetraacetic acid, 0.26 part of Rongalite and distilled water. 5 parts of the mixed liquid was charged to start radical polymerization, and then held at an internal temperature of 70 ° C. for 2 hours to complete the polymerization, and the polyalkyl (Acrylic rubber (a-1) component and Acrylic rubber (a-2) component) A latex of a meth) acrylate composite rubber was obtained.
To this polyalkyl (meth) acrylate composite rubber latex, a mixed solution of 0.06 part of tert-butyl hydroperoxide, 10 parts of methyl methacrylate and 2 parts of n-butyl acrylate was dropped at 70 ° C. over 15 minutes, and then Holding at 70 ° C. for 4 hours, the graft polymerization onto the composite rubber was completed.

  To 400 parts of an aqueous solution containing 5 parts of calcium acetate at 50 ° C., 100 parts of latex containing the obtained graft copolymer is added as a solid content, then heated to 90 ° C., solidified, and washed with water. After repeating the above, the solid content was separated and dried at 80 ° C. for 24 hours to obtain a powder of the graft polymer (B-10).

(Production Example 11) Production of acrylic rubber-based graft copolymer (B-11) Composite rubber was produced in the same manner as in Production Example 9 except that 2 parts of n-butyl acrylate used for graft polymerization was changed to 2 parts of methyl methacrylate. A graft copolymer (M-10) was obtained.

In Examples and Comparative Examples, the following materials were used in the formulations shown in the table.
(A) Aliphatic polyester A-1: Polylactic acid; Lacia H100 (Mitsui Chemicals)
(B) Polyorganosiloxane / acrylic composite rubber graft copolymer or acrylic rubber graft copolymer: The graft copolymers (B-1) to (B-11) produced above were used.
(C) Crystal nucleating agent C-1: LMS300 (talc; inorganic crystal nucleating agent) manufactured by Fuji Talc
C-2: Nippon Kasei's SLIPAX L (ethylene bislauric acid amide; organic crystal nucleating agent)
(D) Filler D-1: Nittobo CS3J948 (glass fiber)
(E) a plasticizer,
E-1: Pluronic F68 (polyethylene glycol / polypropylene glycol copolymer) manufactured by Asahi Denka

Examples 1-10 and Comparative Examples 1-2
After dry blending (A) aliphatic polyester acid and (B) polyorganosiloxane / acrylic composite rubber graft copolymer or acrylic rubber graft copolymer in the blending amounts shown in Table 1, the resin temperature was set to 200 ° C. Melt-mixing pelletization was performed using a set 30 mmφ twin screw extruder.
A test piece was molded at a mold temperature of 40 ° C. using a screw in-line injection molding machine in which the obtained pellets were set at 220 ° C.
Table 2 shows the physical property evaluation results of each sample.

  As Examples 1-10 show, since the aliphatic polyester resin composition of this invention is excellent in both impact resistance and the impact value after a residence, it is excellent in heat resistance and has favorable recyclability. On the other hand, as shown in Comparative Examples 1 and 2, when the aliphatic polyester resin composition of the present invention is not used, the impact strength and heat resistance are insufficient, and it is not suitable for recycling applications.

Examples 11 to 13 and Comparative Example 3
Dry blend of (A) aliphatic polyester, (B) polyorganosiloxane / acrylic composite rubber graft copolymer, acrylic rubber graft copolymer, crystal nucleating agent, filler and plasticizer in the blending amounts shown in Table 2. Then, melt mixing pelletizing was performed using a 30 mmφ twin screw extruder set at 240 ° C.
A test piece was molded at a mold temperature of 80 ° C. using a screw in-line injection molding machine in which the obtained pellets were set at 240 ° C.
Table 3 shows the physical property evaluation results of each sample.

  As shown in Examples 11 to 13, the aliphatic polyester resin composition of the present invention is excellent in both impact resistance and impact value retention after retention.

  On the other hand, as shown in Comparative Example 3, an aliphatic polyester resin composition using a polyorganosiloxane / acrylic composite rubber graft copolymer or an acrylic rubber graft copolymer outside the scope of the present invention has impact resistance and Both impact value retention after staying is inferior.

Claims (2)

(A) an aliphatic polyester and (B) a graft copolymer obtained by grafting a vinyl monomer containing an acrylic acid alkyl ester and / or an aromatic vinyl monomer to an acrylic rubber and / or silicone acrylic rubber. An aliphatic polyester resin composition containing a polymer.   A molded article formed by molding the aliphatic polyester resin composition according to claim 1.