JP6693254B2 - Resin composition and molded article thereof - Google Patents

Description

  The present invention relates to a resin composition containing a polylactic acid polymer and a molded article thereof.

  The amount of plastic products made of polyethylene, polypropylene, polystyrene, polyethylene terephthalate, vinyl chloride, etc., has become enormous at present, and the treatment of these wastes has been highlighted as one of the environmental problems. That is, the current waste treatment is incineration or burial treatment, but when polyethylene or the like is incinerated, for example, the burning calories are high, which damages the incinerator and shortens the life. Further, when polyvinyl chloride or the like is incinerated, harmful gas is generated.

  On the other hand, land is limited for burying plastic products. Further, when discarded in a natural environment, these plastics have extremely high chemical stability, so that they are almost semi-permanently left without being decomposed by microorganisms. Therefore, problems such as damage to the landscape and pollution of the living environment of living things are caused.

  Under these circumstances, plastics that are biodegradable or that decompose in a natural environment have recently attracted attention. It is known that biodegradable plastics gradually disintegrate / decompose in soil or in water due to hydrolysis or biodegradation, and finally become harmless decomposition products by the action of microorganisms. Biodegradable plastics that are currently being put into practical use include natural material-based biocellulose and starch-based plastics, aliphatic polyesters, modified PVA (polyvinyl alcohol), cellulose ester compounds, starch modified products, and blends thereof. The body is roughly divided. Among these biodegradable plastics, aliphatic polyesters are relatively well-balanced in terms of processability, cost, mechanical properties, water resistance and the like and are easy to use for various purposes.

  As the aliphatic polyester, for example, poly (hydroxybutyric acid / valeric acid) is known as a microbial-produced polymer, and polycaprolactone or a condensate of an aliphatic dicarboxylic acid and an aliphatic diol is known as a synthetic polymer. A polylactic acid-based polymer is known as a semi-synthetic polymer.

  Polylactic acid-based polymers have been attracting attention as plant-based plastics that do not use petroleum resources, because they are synthesized using non-petroleum-based raw materials, such as sweet potatoes and corn, and so on. There is a strong movement to replace polylactic acid-based polymers in the applications that used.

  Polylactic acid-based polymers are used for film and sheet applications because of their transparency. However, the polylactic acid type polymer alone has a low strength, and there is a problem that sufficient strength cannot be obtained when used as a film or a sheet. As a method of improving this, Patent Document 1 discloses a method of adding a graft copolymer to a polylactic acid-based polymer. Further, as a method of improving the strength while utilizing the excellent transparency of the polylactic acid polymer, a method of adding a graft copolymer having a specific refractive index to the polylactic acid polymer has been proposed. There is. (See Patent Documents 2 to 3)

JP, 2003-2086396, A International Publication No. 05/123831 Pamphlet International Publication No. 05/085352 Pamphlet

However, strength can be improved by the method proposed in Patent Document 1, and strength can be improved by making use of the transparency of the polylactic acid-based polymer, while the method proposed in Patent Documents 2 and 3 can be obtained. In addition, there is a problem that a bent portion is whitened when the film or sheet is bent (hereinafter, referred to as folded whitening). Further, depending on the type of rubbery polymer used for the graft copolymer, the weather resistance is insufficient, and yellowing occurs when used outdoors or in a place exposed to sunlight. Therefore, it is not suitable for applications requiring low bending whitening property and weather resistance.
An object of the present invention is to provide a molded article which is excellent in weather resistance and has little whitening by bending.

That is, the gist of the resin composition of the present invention is as follows.
[1] Graft copolymer based on 100 parts by mass of polylactic acid polymer (A) 1 to 100% by mass and methyl methacrylate monomer unit-containing acrylic polymer (B) 0 to 99% by mass. A resin composition containing 1 to 50 parts by mass of (C),
The graft copolymer (C) is obtained by graft-polymerizing a vinyl monomer (c2) onto a rubbery polymer (C1) which is acrylic rubber or polyorganosiloxane / acrylic rubber. The mass average particle diameter of the polymer (C) is 10 to 120 nm, the refractive index Rc of the graft copolymer (C), and the total of the polylactic acid polymer (A) and the acrylic polymer (B). A resin composition having a refractive index Rab satisfying the following expression (1).
−0.03 ≦ Rc−Rab ≦ + 0.03 ... Formula (1)
[2] The resin composition according to [1], wherein the graft copolymer (C) has a mass average particle diameter of 10 to 100 nm.
[3] In [1] or [2], the content of the crosslinkable monomer is 0.3 to 10% by mass in the total 100% by mass of the monomers constituting the rubbery polymer (C1). The resin composition described.
[4] The content of the crosslinkable monomer is 1 to 10% by mass in the total 100% by mass of the monomers constituting the rubbery polymer (C1), [1] or [2]. Resin composition.
[5] The content of the crosslinkable monomer is 2 to 10% by mass in the total 100% by mass of the monomers constituting the rubbery polymer (C1), [1] or [2]. Resin composition.
[6] A molded product obtained by molding the resin composition according to any one of [1] to [5].

  According to the resin composition of the present invention, it is possible to provide a molded article which is excellent in weather resistance and has little whitening by bending, and particularly when the sheet or film is subjected to bending molding, blow molding, or vacuum molding, it has a good appearance. A molded product can be easily obtained. Such molded products are particularly suitably used for applications such as building materials, automobiles, toys, stationery and other miscellaneous goods, office automation equipment, home appliances, packages, face plates such as vending machines and pachinko machines that require these physical properties. Be done.

It is a typical sectional view showing one embodiment of bending whitening property evaluation of the present invention.

Hereinafter, the present invention will be described in detail.
The resin composition of the present invention,
Graft copolymer (C) based on 100 parts by mass of polylactic acid polymer (A) 1 to 100 mass% and methyl methacrylate monomer unit-containing acrylic polymer (B) 0 to 99 mass%. A resin composition containing 1 to 50 parts by mass of
The graft copolymer (C) is obtained by graft-polymerizing a vinyl monomer (c2) onto a rubbery polymer (C1) which is acrylic rubber or polyorganosiloxane / acrylic rubber. The mass average particle diameter of the polymer (C) is 10 to 120 nm, the refractive index Rc of the graft copolymer (C), and the total of the polylactic acid polymer (A) and the acrylic polymer (B). The refractive index Rab satisfies the following expression (1).
−0.03 ≦ Rc−Rab ≦ + 0.03 ... Formula (1)

The mass average particle diameter of the graft copolymer (C) can be measured with a capillary type particle size distribution meter.
The refractive index Rc of the graft copolymer (C) can be measured with an Abbe refractometer.
The total refractive index Rab of the polylactic acid-based polymer (A) and the acrylic-based polymer (B) is the mixture of the polylactic acid-based polymer and the acrylic-based polymer that constitute the resin composition in advance, and the Abbe The value obtained by measuring the refractive index with a refractometer.

  By making the graft copolymer (C) the above-mentioned predetermined one, it is possible to obtain a resin composition which gives a molded article having high transparency, excellent strength and weather resistance, and little whitening by bending.

<Polylactic acid-based polymer (A)>
As the polylactic acid-based polymer (A) used in the present invention, a polylactic acid or a lactic acid copolymer obtained by copolymerizing a lactic acid monomer and another component can be used. It is also possible to use mixtures of these polymers.

  Polylactic acid can be synthesized by a conventionally known method. For example, direct dehydration condensation from lactic acid or lactic acid cyclic dimer as described in JP-A-7-33861, JP-A-59-96123, Proceedings of the Symposium on Polymers, Vol. 44, pages 3198-3199. It can be synthesized by ring-opening polymerization of body lactide.

  When performing direct dehydration condensation, any lactic acid of L-lactic acid, D-lactic acid, DL-lactic acid, or a mixture thereof may be used. When ring-opening polymerization is performed, any lactide of L-lactide, D-lactide, DL-lactide, meso-lactide, or a mixture thereof may be used.

  Regarding the synthesis, purification and polymerization operation of lactide, for example, US Pat. No. 4,057,537, Published European Patent Application No. 261572, Polymer Bulletin, 14, 491-495 (1985), and Makromol CheAG-187, 1611-1628 ( 1986) and various other documents.

  The constituent molar ratio (L / D) of the L-lactic acid unit and the D-lactic acid unit in the polylactic acid may be any of 100/0 to 0/100. L / D is preferably 100/0 to 60/40, more preferably 100/0 to 80/20.

  The lactic acid copolymer is a copolymer of a lactic acid monomer or lactide and other components copolymerizable therewith. Other copolymerizable components include dicarboxylic acids having two or more ester bond-forming functional groups, polyhydric alcohols, hydroxycarboxylic acids, lactones, and the like. Examples of the dicarboxylic acid include succinic acid, azelaic acid, sebacic acid, terephthalic acid, isophthalic acid and the like.

  Examples of the polyhydric alcohols include aromatic polyhydric alcohols such as those obtained by adding ethylene oxide to bisphenol; ethylene glycol, propylene glycol, butanediol, hexanediol, octanediol, glycerin, sorbitan, trimethylolpropane, neo. Aliphatic polyhydric alcohols such as pentyl glycol; ether glycols such as diethylene glycol, triethylene glycol, polyethylene glycol and polypropylene glycol.

  Examples of the hydroxycarboxylic acid include glycolic acid, hydroxybutylcarboxylic acid, 3-hydroxybutyric acid, 4-hydroxybutyric acid, 3-hydroxyvaleric acid, 4-hydroxyvaleric acid, 6-hydroxycaproic acid, and others. The thing etc. which are described in the 184417 publication are mentioned.

  Examples of the lactone include glycolide, ε-caprolactone glycolide, ε-caprolactone, β-propiolactone, δ-butyrolactone, β- or γ-butyrolactone, pivalolactone, δ-valerolactone and the like.

  The biodegradability of lactic acid copolymers is affected by the content of lactic acid units in the copolymer. Therefore, the content of lactic acid units in the lactic acid copolymer is preferably 50 mol% or more, more preferably 70 mol% or more, though it depends on the copolymerization component used. The mechanical properties and biodegradability of the obtained product can be improved by the content of the lactic acid unit and the copolymerization component.

  The polylactic acid-based polymer (A) is not particularly limited, but in the case of a crystalline polymer, one having a melting point of 60 to 200 ° C. and a mass average molecular weight of 50,000 to 500,000 is preferably used. The mass average molecular weight is more preferably 100,000 to 300,000.

  Further, for the purpose of obtaining the same effect as in the case of using the copolymer, polylactic acid may be simply blended with another aliphatic polyester. In this case, the content of polylactic acid contained in the blend is preferably 50 mol% or more, and more preferably 70 mol% or more in terms of mol.

  As the polylactic acid-based polymer (A), commercially available products can be used, and examples thereof include Ingeobiopolymers “2003D”, “4032D”, and “4043D” manufactured by Nature Works LLC.

<Acrylic polymer (B)>
The acrylic polymer (B) is a polymer containing a methyl methacrylate monomer unit, and uses a homopolymer of methyl methacrylate or a copolymer of methyl methacrylate and a monomer copolymerizable therewith. can do. When a copolymer is used, it is preferable to use a copolymer containing 50% by mass or more, preferably 70% by mass or more of a methyl methacrylate monomer unit.

  Other monomers copolymerizable with methyl methacrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate and butyl acrylate; other alkyl methacrylates such as ethyl methacrylate and butyl methacrylate; aromatic vinyl monomers such as styrene; Vinyl cyanide monomers such as acrylonitrile; cyclohexylmaleimide, phenylmaleimide, maleic anhydride, glutaric anhydride can also be used.

  Among the above-mentioned monomers, it is preferable to use a copolymer of methyl methacrylate and methyl acrylate from the viewpoint of high transparency and heat resistance.

  The method for producing the acrylic polymer (B) is not particularly limited, and various known methods such as suspension polymerization, bulk polymerization and emulsion polymerization can be applied. The molecular weight of the acrylic polymer (B) is not particularly limited, but a mass average molecular weight of 40,000 to 300,000 is preferable.

  As the acrylic polymer (B), commercially available products can be used, and examples thereof include Acrypet “VH”, “MF”, “MD”, and “UT-100” manufactured by Mitsubishi Rayon Co., Ltd.

  Examples of the acrylic polymer (B) copolymerized with phenylmaleimide include PMI resin "P35S" and "P60S" manufactured by Mitsubishi Rayon Co., Ltd.

<Graft copolymer (C)>
The graft copolymer (C) in the present invention is obtained by graft-polymerizing a vinyl monomer (c2) on a rubbery polymer (C1) which is acrylic rubber or polyorganosiloxane / acrylic rubber.

<Rubber polymer (C1)>
The rubbery polymer used in the graft copolymer of the present invention is acrylic rubber or polyorganosiloxane / acrylic rubber. By using these rubbers as the rubbery polymer, a graft copolymer having excellent weather resistance can be obtained, and yellowing does not occur even when it is used outdoors or in a place exposed to sunlight.

(Acrylic rubber)
The acrylic rubber of the present invention is a rubber obtained by polymerizing an alkyl (meth) acrylate. The acrylic rubber is obtained by polymerizing an alkyl (meth) acrylate, a crosslinking agent (CI) if necessary, and a graft crossing agent (GI) if necessary.

  Specific examples of the alkyl (meth) acrylate are not particularly limited, but methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, tridecyl acrylate, ethoxyethoxyethyl acrylate, methoxy. Examples include tripropylene glycol acrylate, 4-hydroxybutyl acrylate, lauryl acrylate, lauryl methacrylate, stearyl methacrylate and the like. These can be used alone or in combination of two or more. From the viewpoint of strength development, as the alkyl (meth) acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, tridecyl acrylate, lauryl methacrylate, tridecyl methacrylate, stearyl methacrylate and the like are particularly preferable. preferable. The amount of alkyl (meth) acrylate used is preferably 60% by mass or more, and more preferably 70% by mass or more based on 100% by mass of all the monomers constituting the acrylic rubber.

  Examples of the cross-linking agent (CI) include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, divinylbenzene, and polyfunctional methacryl group-modified silicone. Be done. The amount of the crosslinking agent (CI) used is preferably 0 to 10% by mass, more preferably 1 to 10% by mass, and more preferably 2 to 10% in 100% by mass of all the monomers constituting the acrylic rubber. It is more preferable that the content is% by mass.

  As the graft crossing agent (GI), an allyl group alone or a bifunctional or more functional monomer having an allyl group and a (meth) acryloyl group can be used. Examples of such a monomer include allyl methacrylate, Examples thereof include triallyl cyanurate and triallyl isocyanurate. These graft crossing agents (GI) also function as cross-linking agents. The amount of the graft crossing agent (GI) used is preferably 0 to 10% by mass, more preferably 1 to 10% by mass, and more preferably 2 to 10% based on 100% by mass of all the monomers constituting the acrylic rubber. It is more preferable that the content is% by mass.

  The crosslinking agent (CI) and the graft crossing agent (GI) can be used alone or in combination of two or more kinds.

When adjusting the acrylic rubber, an aromatic vinyl monomer may be further used in combination for the purpose of adjusting the refractive index of the graft copolymer (C).
Specific examples of the aromatic vinyl monomer include styrene, α-methylstyrene, vinyltoluene and the like. The amount of the aromatic vinyl monomer used is preferably 20% by mass or less, and more preferably 10% by mass or less, based on 100% by mass of all the monomers constituting the acrylic rubber.

  The acrylic rubber is preferably a polymer having a glass transition temperature of 0 ° C. or lower in terms of strength development. Here, the glass transition temperature of the acrylic rubber is measured as a transition point of Tan δ by a dynamic mechanical property analyzer (DMA).

  The method for producing the acrylic rubber is not particularly limited, but it can be polymerized by a known emulsion polymerization method.

<Polyorganosiloxane / acrylic rubber>
The polyorganosiloxane / acrylic rubber is a rubber composed of a polyorganosiloxane rubber obtained by polymerizing an organosiloxane and the above-mentioned acrylic rubber. The polyorganosiloxane rubber is obtained by polymerizing an organosiloxane, optionally a crosslinking agent (CII), and optionally a graft crossing agent (GII).

  Examples of the organosiloxane include various cyclic members having three or more membered rings, and examples thereof include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and trimethyltriphenylcyclotrisiloxane. , Tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, and the like. Of these, those having a 3- to 6-membered ring are preferably used. These may be used alone or in admixture of two or more. The amount of the organosiloxane used is preferably 80% by mass or more, and more preferably 90% by mass or more, based on 100% by mass of all the monomers constituting the polyorganosiloxane rubber.

  As the crosslinking agent (CII), a trifunctional or tetrafunctional silane-based crosslinking agent, for example, trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetrabutoxy. Examples include silane. In particular, a tetrafunctional crosslinking agent is preferable, and among these, tetraethoxysilane is particularly preferable. The amount of the cross-linking agent (CII) used is preferably 0 to 10% by mass, more preferably 1 to 10% by mass, based on 100% by mass of all the monomers constituting the polyorganosiloxane rubber. More preferably, it is from 10 to 10% by mass.

Examples of the graft crossing agent (GII) include compounds capable of forming a unit represented by the following formula.
^{_{CH 2 = C (R 2)}} -COO- (CH 2) p -SiR 1 n O (3-n) / 2 (GII-1)
^{_{CH 2 = C (R 2)}} -C 6 H 4 -SiR 1 n O (3-n) / 2 (GII-2)
^{_{CH 2 = CH-SiR 1 n}} O (3-n) / 2 (GII-3)
^{_{HS- (CH 2) p -SiR 1}} n O (3-n) / 2 (GII-4)
(In the formula, R ¹ is a methyl group, an ethyl group, a propyl group, or a phenyl group, R ² is a hydrogen atom or a methyl group, n is 0, 1 or 2, and p is 1 to 6. Indicates the number.)

  As the compound capable of forming the unit of the above formula (GII-1), methacryloyloxysiloxane is particularly preferable. Specific examples of methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyl. Examples thereof include ethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, and γ-methacryloyloxybutyldiethoxymethylsilane.

  Examples of the compound capable of forming the unit of the above formula (GII-2) include p-vinylphenyldimethoxymethylsilane.

  Examples of the compound capable of forming the unit of the above formula (GII-3) include vinylsiloxane, and specific examples thereof include tetramethyltetravinylcyclotetrasiloxane.

  Examples of the compound capable of forming the unit of the above formula (GII-4) include γ-mercaptopropyldimethoxymethylsilane, γ-mercaptopropylmethoxydimethylsilane and γ-mercaptopropyldiethoxymethylsilane.

  The amount of the graft crossing agent (GII) used is preferably 0 to 10% by mass, more preferably 0.5 to 5% by mass based on 100% by mass of all the monomers constituting the polyorganosiloxane rubber. preferable.

  The method for producing the polyorganosiloxane rubber is not particularly limited, but it is preferable to polymerize by emulsion polymerization.

  For the production of the latex of the polyorganosiloxane component, for example, the method described in US Pat. No. 2,891,920, US Pat. No. 3,294,725, etc. can be used. In the present invention, for example, a mixed solution of an organosiloxane, a crosslinking agent (CII) and optionally a graft crossing agent (GII) is added in the presence of a sulfonic acid-based emulsifier such as alkylbenzenesulfonic acid or alkylsulfonic acid, for example, a homogenizer or the like. It is preferable to manufacture by a method of shear mixing with water by using. Alkylbenzene sulfonic acid is suitable because it acts as an emulsifying agent for the organosiloxane and at the same time serves as a polymerization initiator. At this time, it is preferable to use a metal salt of alkylbenzene sulfonic acid, a metal salt of alkyl sulfonic acid and the like in combination because it is effective in maintaining the polymer stably during the graft polymerization.

  The acrylic rubber described above can be used as the acrylic rubber in the polyorganosiloxane / acrylic rubber.

The ratio of each rubber component in the polyorganosiloxane / acrylic rubber is 1 to 70% by mass of the polyorganosiloxane rubber and 99 to 30% by mass of the acrylic rubber from the viewpoint of transparency and strength (the total amount of both components is 100% by mass). %) Is preferred.

  The polyorganosiloxane / acrylic composite rubber preferably has a gel content of 80% by mass or more as measured by extraction with toluene at 90 ° C. for 4 hours, from the viewpoint of strength development.

  The method for producing the polyorganosiloxane / acrylic rubber is not particularly limited, but a latex of the polyorganosiloxane rubber is first prepared by emulsion polymerization, and then the monomer constituting the acrylic rubber is made into particles of the polyorganosiloxane rubber latex. Preferred is the method of impregnating with the above and polymerizing this.

<Content of crosslinkable monomer>
The content of the crosslinkable monomer contained in the rubbery polymer (C1) affects both the strength and the folding whitening property of the resin composition. Here, the crosslinkable monomer refers to a crosslinking agent (CI, CII) and a graft crossing agent (GI).

  The total amount of these crosslinkable monomers used is preferably 0.3 to 10% by mass in the total 100% by mass of the monomers constituting the rubbery polymer (C1), and preferably 1 to 10% by mass. %, More preferably 2 to 10% by mass. By setting the total amount of the crosslinkable monomers to be used within this range, bending whitening can be effectively suppressed while maintaining strength.

<Graft>
The graft copolymer (C) can be obtained by graft-polymerizing the vinyl monomer (c2) in the presence of the rubbery polymer (C1) described above.

  The vinyl monomer (c2) is not particularly limited. Specific examples thereof include aromatic vinyl monomers such as styrene, α-methylstyrene and vinyltoluene; methacrylic acid esters such as methyl methacrylate and 2-ethylhexyl methacrylate; acryl such as methyl acrylate, ethyl acrylate and n-butyl acrylate. Acid ester; various vinyl monomers such as vinyl cyanide compounds such as acrylonitrile and methacrylonitrile. These vinyl monomers may be used alone or in combination of two or more.

  The vinyl monomer may contain a crosslinkable monomer in terms of strength and heat resistance. Specific examples thereof include ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, divinylbenzene, and polyfunctional methacryl group-modified silicone, which function as a crosslinking agent. Monomers: Allyl methacrylate, triallyl cyanurate, triallyl isocyanurate and the like.

  A general dropping polymerization can be used for the graft polymerization. Further, the polymerization can be carried out in one stage or in multiple stages.

<Graft copolymer (C)>
The ratio of the rubbery polymer (C1) to the graft in the graft copolymer is preferably 60 to 99 parts by mass, and 70 to 95 parts by mass, based on 100 parts by mass in total of both. More preferably, it is a part. The amount of graft is preferably 1 to 40 parts by mass, more preferably 5 to 30 parts by mass. When the amount of the graft portion is 1 part by mass or more, the dispersibility of the obtained graft copolymer in the resin composition is good and the processability of the resin composition is improved. On the other hand, when the amount of the graft portion is 40 parts by mass or less, the strength development of the graft copolymer is improved.

  The particle size of the graft copolymer (C) affects strength, transparency, and bending whitening property. In order to suppress bending whitening while maintaining strength and transparency, the mass average particle diameter of the graft copolymer (C) is 10 to 120 nm, preferably 10 to 100 nm, and preferably 50 to 100 nm. Is more preferable.

  Examples of the method of adjusting the mass average particle diameter of the graft copolymer (C) to a desired range include a method of adjusting the amount of an emulsifier used during the production of the rubbery polymer (C1).

  The graft copolymer (C) is usually obtained as a latex. The graft copolymer obtained as the latex is preferably recovered as powder or granules by spray recovery or wet coagulation with a coagulant such as acid or salt. However, when it contains a functional group, wet coagulation with an acid is not preferable. This is because when an acid is used, the functional group may be deactivated or the functional group may be adversely affected. When performing wet coagulation using salts, it is preferable to use an alkaline earth metal salt such as calcium acetate, calcium chloride, magnesium sulfate or the like. By using an alkaline earth metal, deterioration such as decomposition of the matrix resin due to moisture and heat can be suppressed as much as possible. If the deterioration of the matrix resin can be suppressed, the wet heat resistance of the molded article made of the resin composition is improved. Moisture and heat resistance affects the strength development of the molded product, and greatly affects the recyclability of the molded product.

  Further, as a recovery method in consideration of recyclability, a spray recovery method that does not include salts for the coagulant itself is effective. At the time of spray recovery, in addition to the graft copolymer, fillers or other polymers can be co-sprayed at the same time and recovered as a powder in which both are combined. By selecting the type of substance to be co-sprayed, it is possible to realize more preferable handleability of the powder property. Examples of components to be co-sprayed include calcium components, silica, and hard vinyl copolymers.

<Resin composition>
The resin composition of the present invention is based on 100 parts by mass of the polylactic acid-based polymer (A) 1 to 100% by mass and the acrylic polymer (B) containing a methyl methacrylate monomer unit 0 to 99% by mass. , 1 to 50 parts by mass of the graft copolymer (C).

  The composition ratio of the polylactic acid polymer (A) and the acrylic polymer (B) can be arbitrarily adjusted within the above range. For example, the higher the amount of the polylactic acid-based polymer (A) is, the more preferable it is for the use where the demand for reducing the environmental load is high, and the higher the amount of the acrylic-based polymer (B) is the preferable for the use where the demand for the heat resistance is high.

  The blending amount of the graft copolymer (C) can be arbitrarily adjusted within the above range, but from the viewpoint of reducing the environmental load, 1 to 30 parts by mass is preferable, and 1 to 20 parts by mass is more preferable. Preferably, 1 to 15 parts by mass is more preferable.

  Rc-Rab, which is the difference between the refractive index Rc of the graft copolymer (C) and the total refractive index Rab of the polylactic acid polymer (A) and the acrylic polymer (B), determines the transparency of the resin composition. affect. The value of Rc-Rab satisfies the following equation (1), and more preferably satisfies the following equation (2).

−0.03 ≦ Rc−Rab ≦ + 0.03 ... Formula (1)
−0.025 ≦ Rc−Rab ≦ + 0.025 ... Formula (2)

  The following method is used in order to keep the refractive index Rc of the graft copolymer (C) and the total refractive index Rab of the polylactic acid polymer (A) and the acrylic polymer (B) within a predetermined range.

  That is, for example, for a resin composition having a high content of the acrylic polymer (B) and a high Rab, an acrylic rubber and a polyorganosiloxane / acrylic rubber having a high acrylic rubber content are used. It is preferable to use the obtained graft copolymer. In this case, it is possible to further increase the refractive index Rc of the graft copolymer by including an aromatic vinyl monomer having a higher refractive index as a copolymerization component when polymerizing the acrylic rubber.

  On the contrary, for a resin composition having a low Rab value, it is preferable to use a graft copolymer obtained by using a polyorganosiloxane / acrylic rubber having a high content ratio of polyorganosiloxane rubber. Furthermore, by using an alkyl (meth) acrylate having a long alkyl chain as the acrylic rubber in the polyorganosiloxane / acrylic rubber, the refractive index Rc of the graft copolymer can be lowered. When a graft copolymer obtained by using an acrylic rubber is used, an acrylic rubber using an alkyl (meth) acrylate having a long alkyl chain is used to lower the refractive index Rc of the graft copolymer. can do.

  Furthermore, the refractive index Rc of the graft copolymer (C) can be adjusted by adjusting the type and amount of the vinyl-based monomer that is graft-copolymerized with the rubber polymer.

  In the present invention, polystyrene, HIPS, ABS, AS, MS resins and other styrene resins, polyphenylene ether resins, polycarbonate resins, polyester resins, polyacetal resins, polyvinyl chloride resins are used as long as the transparency is not impaired. Other thermoplastic resins such as polyolefin resins such as polyethylene, polypropylene and the like can be added.

  The blending amount of these polymers is preferably 10 parts by mass or less, more preferably 5 parts by mass, and most preferably 100 parts by mass with respect to the total of 100 parts by mass of the polylactic acid polymer (A) and the acrylic polymer (B). Is 0 part by mass.

  When preparing the resin composition of the present invention, as long as it does not impair the physical properties, at the desired stage of compounding the thermoplastic resin, kneading, molding, etc., conventionally known various flame retardants, stabilizers, etc. Can be added.

  The flame retardant that can be used in the resin composition of the present invention is not particularly limited, but when a halogen-based flame retardant, a phosphoric acid-based flame retardant, or a silicone-based flame retardant is used, high flame retardancy is exhibited without impairing the strength or the like. It is possible to do so, which is preferable. Examples of such flame retardants include halogen-containing compounds, phosphoric acid compounds, silicone compounds, halogen-containing organic metal salt compounds, and the like.

  Specific examples of the flame retardant include phosphoric acid compounds such as phosphoric acid ester compounds, phosphorous acid ester compounds and condensed phosphoric acid ester compounds; aluminum hydroxide; acid antimony compounds such as antimony trioxide and antimony pentoxide; Halogen-containing compounds such as halogenated phosphoric acid ester compounds, halogen-containing condensed phosphoric acid ester compounds, chlorinated paraffins, brominated aromatic triazines, brominated aromatic compounds such as brominated phenylalkyl ethers; sulfone or sulfate compounds; epoxy System reactive flame retardants; and the like.

  From the viewpoint of transparency, the blending amount of the flame retardant is preferably 10 parts by mass or less, and more preferably 5 parts by mass with respect to 100 parts by mass as the total of the polylactic acid polymer (A) and the acrylic polymer (B). However, the most preferable amount is 0 part by mass.

  Examples of the stabilizer include metallic stabilizers and other stabilizers.

  Examples of the metal stabilizer include lead stabilizers such as tribasic lead sulfate, dibasic lead phosphite, basic lead sulfite, and lead silicate; potassium, magnesium, barium, zinc, cadmium, lead, etc. Metal soaps derived from the following metals and fatty acids such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, hydroxystearic acid, oleic acid, ricinoleic acid, linoleic acid, and behenic acid. Stabilizers: Organotin stabilizers derived from alkyl groups, ester groups, etc. and fatty acid salts, maleates, sulfides, etc .; Ba-Zn series, Ca-Zn series, Ba-Ca-Sn series, Ca-Mg-Sn-based, Ca-Zn-Sn-based, Pb-Sn-based, Pb-Ba-Ca-based and other complex metal soap-based stabilizers; metals such as barium and zinc; and 2-ethylhexa Acids, isodecanoic acid, branched fatty acids such as trialkylacetic acid, unsaturated fatty acids such as oleic acid, ricinoleic acid and linoleic acid, alicyclic acids such as naphthenic acid, carboxylic acids such as carboxylic acid, benzoic acid, salicylic acid and substituted derivatives thereof. Stabilizers derived from two or more kinds of organic acids such as aromatic acids; dissolved in organic solvents such as petroleum hydrocarbons, alcohols, glycerin derivatives, etc., and further phosphites and epoxy compounds Examples of the metal salt liquid stabilizer include a color-developing agent, a transparency improver, a light stabilizer, an antioxidant, a plate-out inhibitor, and a stabilizing aid such as a lubricant.

  Other stabilizers include epoxy compounds such as epoxy resin, epoxidized soybean oil, epoxidized vegetable oil, and epoxidized fatty acid alkyl ester; phosphorus is substituted with an alkyl group, an aryl group, a cycloalkyl group, an alkoxyl group, and propylene. Organic phosphite having a dihydric alcohol such as glycol, hydroquinone, and an aromatic compound such as bisphenol A; 2,4-di-t-butyl-3-hydroxytoluene (BHT), dimerized with sulfur or methylene group UV absorbers such as hindered phenols such as bisphenol, salicylic acid esters, benzophenone and benzotriazole; light stabilizers of hindered amines or nickel complex salts; UV shielding agents such as carbon black and rutile titanium oxide; trimerol propane, penta Erythritol Polyhydric alcohols such as sorbitol and mannitol, nitrogen-containing compounds such as β-aminocrotonic acid esters, 2-phenylindole, diphenylthiourea and dicyandiamide; sulfur-containing compounds such as dialkylthiodipropionic acid esters; acetoacetic acid esters and dehydroacetic acid , Β-diketones and other keto compounds; organosilicon compounds; boric acid esters; and the like. These stabilizers can be used alone or in combination of two or more kinds.

  From the viewpoint of transparency, the amount of the stabilizer used is preferably 5 parts by mass or less, and more preferably 2 parts by mass with respect to 100 parts by mass as the total of the polylactic acid polymer (A) and the acrylic polymer (B). However, the most preferable amount is 0 part by mass.

  In the resin composition of the present invention, other, processing aids, plasticizers, lubricants, flame retardants, heat resistance improvers, release agents, crystal nucleating agents, fluidity improvers, colorants, antistatic agents, conductivity imparting Agents, surfactants, antifogging agents, antibacterial agents and the like can be added.

  Examples of the processing aid include (meth) acrylic acid ester-based copolymers. From the viewpoint of transparency, the amount of the processing aid used is preferably 15 parts by mass or less, and more preferably 5 parts by mass, based on 100 parts by mass of the polylactic acid polymer (A) and the acrylic polymer (B). Preferred, but most preferred is 0 parts by weight.

  As the plasticizer, for example, dibutyl phthalate, dioctyl phthalate, diisodecyl phthalate, diisononyl phthalate, diundecyl phthalate, trioctyl trimellitate, alkyl ester of aromatic polybasic acid such as triisooctyl trimellitate; dibutyl adipate, dioctyl. Alkyl esters of fatty acid polybasic acids such as adipate, disiononyl adipate, dibutyl azelate, dioctyl azelate, diisononyl azelate; phosphoric acid esters such as tricresyl phosphate; adipic acid, azelaic acid, sebacic acid, phthalic acid And polyhydric carboxylic acids such as ethylene glycol, 1,2-propylene glycol, 1,2-butylene glycol, 1,3-butylene glycol, and 1,4-butylene glycol Polyester plasticizer such as a compound obtained by sealing the end of a polycondensate having a molecular weight of about 600 to 8,000 with a monohydric alcohol or a monocarboxylic acid; epoxidized soybean oil, epoxidized linseed oil, epoxidized tall oil Epoxy plasticizers such as fatty acid-2-ethylhexyl; chlorinated paraffins and the like. From the viewpoint of transparency, the amount of the plasticizer used is preferably 30 parts by mass or less, and more preferably 10 parts by mass with respect to 100 parts by mass as the total of the polylactic acid polymer (A) and the acrylic polymer (B). However, the most preferable amount is 0 part by mass.

  Examples of the lubricant include liquid hydrocarbons, pure hydrocarbons such as low molecular weight polyethylene, halogenated hydrocarbons, fatty acids such as higher fatty acids and oxyfatty acids, fatty acid amides, polyhydric alcohol esters of fatty acids such as glycerides, and fatty alcohol esters of fatty acids. (Ester wax), metal soap, fatty alcohol, polyhydric alcohol, polyglycol, polyglycerol, partial ester of fatty acid and polyhydric alcohol, ester of fatty acid and polyglycol, partial ester of polyglycerol, etc., (meth) acrylic acid ester Examples thereof include system copolymers. Examples of the heat resistance improver include (meth) acrylic acid ester-based copolymers, imide-based copolymers, and styrene-acrylonitrile-based copolymers. From the viewpoint of transparency, the amount of the lubricant used is preferably 5 parts by mass or less, and more preferably 1 part by mass with respect to 100 parts by mass as the total of the polylactic acid polymer (A) and the acrylic polymer (B). , And most preferably 0 part by mass.

  The method for producing the resin composition of the present invention is not particularly limited. Various conventionally known mixing methods can be used, and the melt mixing method is usually preferable. Also, a small amount of solvent may be used if necessary. As an apparatus used for mixing, an extruder, a Banbury mixer, a roller, a kneader and the like can be mentioned. These devices may be operated batchwise or continuously. The order of mixing the components is not particularly limited.

  The molded article of the present invention can be obtained by molding the resin composition described above. The molding method is not particularly limited, and a method suitable for the resin composition of the present invention may be selected from known molding methods. For example, a method of molding using various molding machines such as an extruder, an injection molding machine, a blow molding machine, an inflation molding machine and a calender molding machine can be mentioned. Of these, from the viewpoint of imparting particularly high transparency, it is preferable to mold by an extruder, an injection molding machine, a blow molding machine, or a calender molding machine. In addition, secondary processing such as bending and blow molding may be performed using a molded product that is primarily molded by the above method.

  The molded product thus obtained can be used for, for example, building materials, automobiles, toys, stationery and other miscellaneous goods, OA equipment, home appliances, packages, vending machines, face plates for pachinko machines, etc. Since it has excellent heat resistance and weather resistance, has little whitening by folding, and can easily obtain molded products with good appearance when folding, blow molding, or vacuum forming a sheet or film, it is especially suitable for packages, vending machines and pachinko machines. It is preferably used as a face plate for the above.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. The present invention is not limited to these examples.
Further, in this example, "parts" and "%" mean "parts by mass" and "% by mass" unless otherwise specified.
Various evaluations were performed by the following methods.

(1) Measurement of mass average particle diameter The latex of the graft copolymer was diluted with distilled water and used as a sample, and the measurement was carried out using a CHDF2000 type particle size distribution meter manufactured by MATEC, USA. The measurement conditions were standard conditions recommended by MATEC. Using a dedicated particle separation capillary type cartridge and carrier liquid, the liquidity is almost neutral, the flow rate is 1.4 ml / min, the pressure is about 4000 psi, the temperature is 35 ° C, and the diluted latex has a concentration of about 3%. A 0.1 ml sample was used for the measurement. As the standard particle size substance, a total of 12 points of monodisperse polystyrene with a known particle size manufactured by DUKE, USA were used within the range of 0.02 μm to 0.8 μm.

(2) Preparation of test piece for evaluation Using a different direction conical twin-screw extruder (Laboplast Mill, manufactured by Toyo Seiki Seisakusho, Ltd.) equipped with a slit die, polylactic acid polymer (A), acrylic polymer (B) and the graft copolymer (C) were melt-kneaded at a predetermined ratio and extrusion-molded to obtain a belt-shaped resin composition molded product having a width of 8 mm and a thickness of 0.7 mm.
The obtained strip-shaped resin composition molded body was cut into a length of 200 mm with scissors to obtain a test piece for evaluation.

(3) Measurement of refractive index / total refractive index Rab of polylactic acid polymer (A) and acrylic polymer (B) Resin composition prepared only from polylactic acid polymer (A) and acrylic resin (B) Using the molded article, a thin film having a thickness of about 1 mm was produced by a heating press method (190 ° C., preheating 3 minutes, pressurization 5 minutes, and then cooling 2 minutes). The obtained thin film was measured with an Abbe refractometer according to ASTM-D542. A saturated aqueous solution of zinc chloride was used as the contact liquid.
-Measurement of the refractive index Rc of the graft copolymer (C) From the powder of the graft copolymer (C) by a hot pressing method (150 ° C, 5 minutes of preheating, 1 minute of pressurization, then 2 minutes of cooling). A thin film of about 1 mm was prepared. Using the thin film, the refractive index was measured with an Abbe refractometer according to ASTM-D542. A saturated aqueous solution of zinc chloride was used as the contact liquid.

(4) Evaluation of strength The cut portion of the evaluation test piece was visually observed and evaluated based on the presence or absence of cracks.
＋: There is a crack in the cut part −: There is no crack in the cut part

(5) Evaluation of Transparency Using the above-mentioned evaluation test piece, the test piece prepared in Comparative Example 3 described later was designated as "+", and the evaluation was performed visually based on this.
++: Excellent in transparency +: Equivalent to Comparative Example 3 −: Poor in transparency

(6) Evaluation of Bending Whitening Property FIG. 1 is a schematic view of an apparatus used for a bending test. The folding whitening property was evaluated by the following method using the apparatus shown in FIG.
Both ends of the test piece 100 for evaluation are fixed to a metal spacer 101 having a thickness of 3 mm, and the spacer 101 is pressed together at room temperature at a speed of 750 mm / min to bend the center portion of the test piece 100 at a constant curvature and bending speed. It was After extending the bent portion of the test piece 100, the degree of whitening of the bent portion was visually observed, and the test piece manufactured in Comparative Example 3 described later was marked "-", and evaluation was performed based on this.
++: Significantly less whitening ++: Less whitening +: Slightly less whitening −: Equivalent Also, those in which the bent portion was broken were classified as “undecidable”.

(7) Evaluation of weather resistance In accordance with JIS K7350-4, the test piece for evaluation was exposed for 500 hours using a sunshine weather meter (condition: 63 ° C, 50%, water spraying time 12 minutes / 60 minutes). The color tone of the treated test piece and the untreated test piece were visually observed and evaluated.
+: No yellowing −: Yellowing

(Production Example 1) Production of acrylic rubber graft copolymer (M-1):
75 parts of butyl acrylate, 0.38 part of allyl acrylate (corresponding to 0.5% of butyl acrylate), 0.23 part of tert-butyl hydroperoxide (corresponding to 0.3 part of butyl acrylate) The amount) was mixed to obtain a monomer mixed liquid (MM1).

A separable flask equipped with a condenser and a stirring blade was charged with 174 parts of deionized water, 0.02 part of sodium carbonate, and 1.5 parts of sodium dodecylbenzenesulfonate, and heated to 80 ° C. with nitrogen substitution and mixing with stirring. , 0.8 × 10 ⁻⁴ parts of ferrous sulfate, 2.3 × 10 ⁻⁴ parts of ethylenediaminetetraacetic acid disodium salt, 0.23 parts of Rongalit and 3 parts of deionized water were added and held for 10 minutes. did. 2.5% of the monomer mixed solution (MM1) was added all at once, and then the mixture was kept at 80 ° C. for 15 minutes to complete the first-stage polymerization. Next, 97.5% of the monomer mixture liquid (MM1) was added dropwise over 240 minutes, and then the mixture was held at 80 ° C. for 120 minutes to complete the second-stage polymerization, and an acrylic rubber latex was obtained.

  A mixture of 0.05 parts Rongalit and 0.6 parts deionized water was added to the latex of acrylic rubber, and the mixture was held for 15 minutes, then 0.04 parts of tert-butyl hydroperoxide and 24.9 of methyl methacrylate were added. Part and a mixed solution of 0.1 part of n-butyl acrylate were added dropwise at 80 ° C. for 90 minutes, and then the mixture was maintained at 80 ° C. for 60 minutes to complete the graft polymerization, and the acrylic rubber graft copolymer (M- A latex of 1) was obtained.

  A 0.5% calcium acetate aqueous solution was added to the latex of the graft copolymer (M-1) to cause coagulation, and the mixture was heat-treated and solidified at 90 ° C. Then, the coagulated product was washed with deionized water and dried at 75 ° C. for 16 hours to obtain a powdery acrylic rubber graft copolymer (M-1).

(Production Examples 2-3) Production of acrylic rubber graft copolymers (M-2) to (M-3):
A latex and powder of acrylic rubber graft copolymers (M-2) to (M-3) were prepared in the same manner as in Production Example 1 except that (MM2) to (MM3) shown in Table 1 were used as the monomer mixed liquid. Acrylic rubber graft copolymers (M-2) to (M-3) were obtained.

(Production Example 4) Production of acrylic rubber graft copolymer (M-4):
A latex of the acrylic rubber graft copolymer (M-4) and a powdery acrylic rubber graft copolymer (M were prepared in the same manner as in Production Example 3 except that the amount of sodium dodecylbenzenesulfonate charged was 1.0 part. -4) was obtained.

(Production Example 5) Production of acrylic rubber graft copolymer (M-5):
In a separable flask equipped with a condenser and a stirring blade, deionized water 200 parts, Rongalit 0.28 parts, ferrous sulfate 0.3 × 10 ⁻⁴ parts, ethylenediaminetetraacetic acid disodium salt 0.8 × 10 ^−4. Part, sodium carbonate 0.03 part and phosphanol RS-610NA (manufactured by Toho Kagaku Co., Ltd.) 0.31 part were charged, and the mixture was heated while being replaced with nitrogen and mixed and stirred. When the temperature reached 80 ° C, a monomer mixture liquid (MM5) containing the following components was added dropwise over 180 minutes, and the mixture was kept at 80 ° C for 120 minutes to complete the polymerization.

(Monomer mixture (MM5))
Styrene 11.6 parts n-Butyl acrylate 50.9 parts Allyl methacrylate 0.56 parts Tertiary butyl hydroperoxide 0.19 parts Phosphanol RS-610NA 0.69 parts

  Then, a mixed solution of 0.08 part of Rongalit and 3 parts of deionized water was added, and after holding for 15 minutes, 35.6 parts of methyl methacrylate, 1.9 parts of methyl acrylate, and 0.16 parts of tert-butyl hydroperoxide. , Octyl mercaptan 0.16 parts and phosphanol RS-610NA 0.25 parts were added dropwise over 120 minutes, and the graft polymerization was completed by holding the mixture at 80 ° C. for 60 minutes to complete the acrylic rubber graft copolymer. A latex of (M-5) was obtained.

  A 1.6% calcium acetate aqueous solution was added to the latex of the graft copolymer (M-5) to cause coagulation, and the mixture was heat-treated and solidified at 90 ° C. Then, the coagulated product was washed with deionized water and dried at 75 ° C. for 16 hours to obtain a powdery acrylic rubber graft copolymer (M-5).

(Production Example 6) Production of acrylic rubber graft copolymer (M-6):
A monomer mixture liquid (MM6) consisting of the following components was added to 157 parts of deionized water in which 1.9 parts of disodium dodecyldiphenyl ether sulfonate was dissolved, pre-stirred at 10,000 rpm with a homomixer, and further 20 MPa with a homogenizer. It was emulsified and dispersed under the pressure of to obtain a (meth) acrylate emulsion.

(Monomer mixture (MM6))
2-Ethylhexyl acrylate 99.5 parts Allyl methacrylate 0.50 parts

This emulsion was transferred to a separable flask equipped with a condenser and a stirring blade, 0.5 part of tert-butyl hydroperoxide was added, and then the mixture was heated while being replaced with nitrogen and mixed and stirred. At 50 ° C., a mixed solution of 0.1 × 10 ⁻² parts of ferrous sulfate, 0.3 × 10 ⁻² parts of ethylenediaminetetraacetic acid disodium salt, 0.24 parts of Rongalit and 3 parts of deionized water. Was charged and held at 60 ° C. for 90 minutes to complete the first-stage polymerization step to obtain an acrylic rubber latex.

In a separable flask equipped with a condenser and a stirring blade, 20 parts of the latex of the acrylic rubber in terms of solid content, 0.28 part of tertiary butyl hydroperoxide, 68.6 parts of n-butyl acrylate and 1. 4 parts were charged, nitrogen substitution and heating with mixing and stirring were performed, and when the temperature reached 45 ° C., ferrous sulfate 0.1 × 10 ⁻² parts, ethylenediaminetetraacetic acid disodium salt 0.3 × 10 ⁻² parts, A mixed solution of 0.3 parts of Rongalit and 3 parts of deionized water was added, and the mixture was kept at 65 ° C. for 60 minutes.

  Then, a mixed solution of 10 parts of methyl methacrylate and 0.05 part of tert-butyl hydroperoxide was added dropwise at 65 ° C. for 30 minutes and then kept at 65 ° C. for 60 minutes to complete the graft polymerization. A latex of copolymer (M-6) was obtained.

  A 0.6% calcium acetate aqueous solution was added to the latex of the graft copolymer (M-6) to cause coagulation, and the mixture was heat-treated and solidified at 90 ° C. Then, the coagulated product was washed with deionized water and dried at 75 ° C. for 16 hours to obtain a powdery acrylic rubber graft copolymer (M-6).

(Production Example 7) Production of butadiene / acrylic rubber graft copolymer (M-7):
(1) Production of butadiene / acrylic rubber polymer latex A 70 L autoclave was charged with the following components and heated.

1,3-Butadiene 20 parts n-Butyl acrylate 80 parts Beef tallow fatty acid potassium 0.93 parts M-lauroyl sarcosine sodium 0.39 parts Diisopropylbenzene peroxide 0.22 parts Deionized water 200 parts

At 43 ° C., ferrous sulfate 0.2 × 10 ⁻² parts, dextrose 0.16 parts, sodium pyrophosphate 0.24 parts, ethylenediaminetetraacetic acid disodium salt 0.9 × 10 ⁻³ parts Then, a mixture of 5 parts of deionized water was added to start the reaction, and the temperature was further raised to 60 ° C. and kept for 300 minutes.

  Next, 0.39 part of tallow fatty acid potassium and 0.16 part of M-lauroyl sarcosine sodium were added to obtain a rubber polymer latex.

(2) Polymerization of carboxyl group-containing copolymer An emulsion of the carboxyl group-containing copolymer was prepared by charging the following components in a separable flask equipped with a condenser and a stirring blade and polymerizing at 63 ° C for 4 hours. ..

n-Butyl acrylate 85 parts Methacrylic acid 15 parts Sodium oleate 1.75 parts Sodium dioctyl sulfosuccinate 3.75 parts Potassium persulfate 0.3 parts Deionized water 200 parts

  The conversion of the obtained carboxyl group-containing copolymer emulsion was 98%, and the pH was 5.0.

(3) Production of butadiene / acrylic rubber graft copolymer (M-7) In a separable flask equipped with a condenser and a stirring blade, the butadiene / acrylic rubber polymer latex obtained in (1) was converted to a solid content of 80. Parts, 2.0 parts of the carboxyl group-containing copolymer obtained in (2) in terms of solid content was charged, and the mixture was stirred at room temperature for 30 minutes.

  Next, 2.0 parts of potassium vinyl succinate and 0.6 parts of sodium formaldehyde sulfoxylate were added, the internal temperature was kept at 70 ° C., and 19 parts of methyl methacrylate and 1.0 part of n-butyl acrylate were added, After a mixed solution with 0.08 part of cumene hydroxy peroxide was added dropwise over 70 minutes, the mixture was held for 90 minutes to complete the graft polymerization, and a latex of a butadiene / acrylic rubber graft copolymer (M-7) was obtained.

  After adding 0.5 part of butylated hydroxytoluene to the graft copolymer latex, an aqueous solution of 18.8% calcium acetate was added to cause coagulation and heat treatment at 90 ° C. to solidify. Then, the coagulated product was washed with deionized water and dried at 75 ° C. for 16 hours to obtain a powdery butadiene / acrylic rubber graft copolymer (M-7).

  Of the graft copolymers obtained in the above Production Examples 1 to 7, of the monomers constituting the rubbery polymer and the crosslinkable monomer in 100% of the total of the monomers constituting the rubbery polymer. Table 2 shows the content, the mass average particle diameter, and the refractive index.

The abbreviations in the table indicate the following monomers, respectively.
n-BA; n-butyl acrylate AMA; allyl methacrylate BDMA; 1,3-butylene glycol dimethacrylate St; styrene 2EHA; 2-ethylhexyl acrylate Bd; 1,3-butadiene

[Examples 1 to 4, Comparative Examples 1 to 3]
As the polylactic acid polymer (A), Ingeo biopolymer 4032D (manufactured by Nature Works LLC) was used. Graft copolymers (M-1) to (M-6) were used as the graft copolymer (C). After hand-blending each material in the ratio shown in Table 3, using a different direction conical twin screw extruder (Laboplast Mill, manufactured by Toyo Seiki Seisakusho, Ltd.) equipped with a slit die, barrel temperature 185 ° C., slit die Extrusion molding was performed at a temperature of 180 ° C. and a screw rotation speed of 30 rpm, and the obtained strip-shaped resin composition molded body was cut to prepare a test piece, which was provided for each evaluation. The results are shown in Table 3.

[Example 5, Comparative Examples 4 to 5]
As the polylactic acid polymer (A), Ingeo biopolymer 4032D (manufactured by Nature Works LLC) was used. As the acrylic polymer (B), Acrypet VH (manufactured by Mitsubishi Rayon Co., Ltd., methyl methacrylate (MMA) -methyl acrylate (MA) copolymer, mass average molecular weight (GPC measurement) = 60,000) was used. .. As the graft copolymer (C), the graft copolymers (M-5) and (M-7) were used. After hand-blending each material at the ratio shown in Table 4, using a different direction conical twin-screw extruder (Laboplast Mill, manufactured by Toyo Seiki Seisakusho, Ltd.) equipped with a slit die, barrel temperature 185 ° C., slit die Extrusion molding was performed at a temperature of 180 ° C. and a screw rotation speed of 30 rpm, and the obtained strip-shaped resin composition molded body was cut to prepare a test piece, which was provided for each evaluation. The results are shown in Table 4.

  From the results of this example and comparative examples, it is understood that the resin composition of the present invention gives a molded product which is excellent in strength, transparency and weather resistance and has little whitening by folding.

(Comparative Example 1 and Comparative Example 4)
Since the thermoplastic resin compositions of Comparative Example 1 and Comparative Example 4 did not contain the graft copolymer, the strength was insufficient, and the test piece broke during bending whitening evaluation.

(Comparative example 2)
In the thermoplastic resin composition of Comparative Example 1, the Rc-Rab value was greater than 0.03, so the transparency was low and the test piece became cloudy.

(Comparative example 3)
Since the thermoplastic resin composition of Comparative Example 3 had a large particle diameter of the graft copolymer, whitening in bending whitening evaluation was large.

(Comparative example 5)
The thermoplastic resin composition of Comparative Example 5 contained no crosslinkable monomer in the rubber-like polymer, and thus showed a large amount of whitening in the bending whitening evaluation. Further, since the rubber-like polymer contained a diene rubber, yellowing was observed in the weather resistance test.

  According to the resin composition of the present invention, it is possible to provide a molded product which is excellent in strength, transparency, and weather resistance, and has little whitening by bending, and particularly when the sheet or film is bent, blow-molded, or vacuum-formed. A molded product having a good appearance can be easily obtained. Therefore, the resin composition of the present invention can be used as a substitute for petroleum-based general-purpose plastics such as transparent polyvinyl chloride resin and polyethylene terephthalate that have been conventionally used, and can be used as building materials, automobiles, toys, stationery and other miscellaneous goods, and OA. It can be widely used for appliances, home appliances, packages, and face plates for vending machines and pachinko machines.

100 test piece 101 metal spacer

Claims (3)

With respect to a total of 100 parts by mass of 1 to 100% by mass of the polylactic acid polymer (A) and 0 to 99% by mass of the acrylic polymer (B) containing a methyl methacrylate monomer unit,
A resin composition containing 1 to 50 parts by mass of a graft copolymer (C),
The graft copolymer (C) is
It is obtained by graft-polymerizing a vinyl monomer (c2) onto a rubbery polymer (C1) which is an acrylic rubber ,
The total content of the cross-linking agent and the graft crossing agent is 1 to 2.44% by mass in 100% by mass of the total amount of the monomers constituting the rubbery polymer (C1),
The mass average particle diameter of the graft copolymer (C) is 10 to 120 nm,
A resin in which the refractive index Rc of the graft copolymer (C) and the total refractive index Rab of the polylactic acid polymer (A) and the acrylic polymer (B) satisfy the following formula (1): Composition.
−0.03 ≦ Rc−Rab ≦ + 0.03 ... Formula (1)   The resin composition according to claim 1, wherein the graft copolymer (C) has a mass average particle diameter of 10 to 100 nm. Molded article obtained by molding the resin composition according to any one of claims 1 or 2.