JP5396681B2 - Flame retardant polylactic acid-based thermoplastic resin composition and molded article thereof - Google Patents

Description

  The present invention relates to a flame retardant polylactic acid-based thermoplastic resin composition capable of providing a molded article having excellent mechanical properties such as impact resistance, heat resistance, flame retardancy, moldability, and appearance, and the flame retardant polylactic acid. The present invention relates to a molded product formed by molding a thermoplastic resin composition.

  In recent years, the problems faced by modern society and modern industry, such as the depletion of petroleum resources and global warming, have been highlighted, and it has been emphasized how to build an environmentally friendly system. Recycling is one of the measures to minimize the use of petroleum resources and to minimize the emission of carbon dioxide into the atmosphere. Recycling has been attracting attention because unnecessary resin that is discharged is reused without being discarded. Another approach that has attracted attention is the use of plant-derived resins. Since plants absorb carbon dioxide and release oxygen, it is thought that there is no increase or decrease in carbon dioxide in the atmosphere, and plant-derived resins produced using this plant as a raw material can stop global warming. It is also important to use only a small amount of petroleum resources.

  Plant-derived resins have been initially studied for use as biodegradable resins and have been commercialized in relation to films, sheets, fibers, etc., but are not sufficiently widespread in many fields. The major factors include drawbacks such as low impact resistance and heat resistance compared to conventional petroleum-derived resins.

  A typical example of such plant-derived resins is polylactic acid resin (PLA). In recent years, many studies have been conducted on polylactic acid resins, and the physical properties that are inferior to conventional petroleum-derived resins are not biodegradable, but are based on the fact that they are derived from plants. It is proceeding in the direction of solution.

  However, even if such alloying is attempted, it has not yet been possible to cover all fields of petroleum-derived resins. One of the major factors is the flame retardant field. Although high flame retardancy is required in the electric and electronic fields, it is difficult to improve flame retardancy because polylactic acid itself is easily burned. Therefore, it has been desired to develop a polylactic acid resin that can be used in the electric and electronic fields and has excellent properties such as flame retardancy, mechanical properties, heat resistance, and the appearance of a molded product.

  In general, various studies have been made to improve the flame retardancy of resins, and similar efforts have been made when polylactic acid resins are used.

  For example, Japanese Patent Laid-Open No. 2003-192925 discloses a method of adding a phosphorus-based flame retardant, and Japanese Patent Laid-Open No. 2004-256809 discloses a method of adding a flame-retardant PET. However, the flame retardancy is not sufficient for use in the electric / electronic field.

Patent Document 3 “Japanese Patent Laid-Open No. 2004-277575” discloses a method of adding a silicone compound, and Patent Document 4 “Japanese Patent Laid-Open No. 2004-190026” includes a method of adding a resin other than PLA. However, Patent Document 5 “Japanese Patent Application Laid-Open No. 2005-162872” discloses a method of adding polybutylene succinate and a phosphorus compound. However, all of these are good results in flame retardancy, but in terms of impact resistance, heat resistance, etc., they are not sufficiently functional compared to resins conventionally used in the electronic / electric field. .
JP 2003-192925 A JP 2004-256809 A JP 2004-277575 A JP 2004-190026 JP JP 2005-162872 A

  The present invention solves the above-described problems in the prior art and has a flame-retardant polylactic acid-based thermoplastic resin composition having mechanical strength such as practically sufficient impact strength, heat resistance, flame retardancy, moldability, and appearance. And it aims at providing the molded article formed by shape | molding this flame-retardant polylactic acid-type thermoplastic resin composition.

As a result of diligent efforts to verify and improve conventional techniques, the present inventors have blended impact modifiers and flame retardants with polylactic acid resin, rubber reinforced resin, and aromatic polycarbonate resin, thereby improving mechanical properties and heat resistance. As a result, it has been found that not only the properties but also the high flame retardancy can be obtained at the same time.

That is, the gist of the present invention is a total of 10 to 50 parts by weight of the polylactic acid resin (A), 5 to 35 parts by weight of the following rubber-reinforced resin (B), and 45 to 85 parts by weight of the aromatic polycarbonate resin (C). In addition, the impact modifier (D) described below is included with respect to a total of 100 parts by weight of the polylactic acid resin (A), the rubber-reinforced resin (B), and the aromatic polycarbonate resin (C). It exists in a flame-retardant polylactic acid-type thermoplastic resin composition characterized by including 0.1-8 weight part and a flame retardant (E) 0.1-25 weight part.
Rubber-reinforced resin (B): rubber-containing graft copolymer (b-1) obtained by graft-polymerizing a hard (co) polymer to a rubbery polymer, wherein the rubbery polymer is an acrylic rubber, A rubber reinforced resin containing a (meth) acrylic resin component in a hard (co) polymer,
Or a rubber-containing graft copolymer (b-1) obtained by graft-polymerizing a hard (co) polymer to a rubbery polymer, wherein the rubbery polymer is a butanediene rubber; and (meth) rigid (co) polymer containing an acrylic resin component (b-2) consisting of a rubber-reinforced resin impact modifier (D): a copolymer of acrylic and methacrylic acid esters, fluorine-based Mixed with (co) polymer

  According to the present invention, characteristics such as flame retardancy, mechanical characteristics, heat resistance, etc., which have been problems in the electric / electronic field, are solved, and a good molded product can be provided with a molding cycle equivalent to that of existing resins. .

  Moreover, in this invention, by mix | blending 0.1-60 weight part of flame retardant auxiliary materials (F) with respect to a total of 100 weight part of polylactic acid resin (A) and a flame retardant (E), it is more. Higher flame retardancy can be expressed.

Furthermore, by adding 1 to 18 parts by weight of the appearance improving material (G) to 100 parts by weight of the total of the polylactic acid resin (A) and the aromatic polycarbonate resin (C), flame retardancy and mechanical properties are obtained. It is possible to improve the appearance of the molded product, which has been one of the problems, without impairing the characteristics such as heat resistance, and to realize an excellent appearance equivalent to the ABS resin.

  The rubber-reinforced resin (B) used in the present invention includes 30 to 95% by weight of a rubber-containing graft copolymer (b-1) obtained by graft polymerization of a hard (co) polymer to a rubbery polymer. (B-2) 5 to 70% by weight (100% by weight in total of (b-1) and (b-2)), and (meth) in the hard (co) polymer (b-2) What contains an acrylic resin component is preferable, The content of the (meth) acrylic resin component in this hard (co) polymer (b-2) is 20 to 100% by weight, and this (meth) acrylic The monomer constituting the resin component includes a methacrylic acid ester and optionally an acrylic acid ester, and the weight ratio of the methacrylic acid ester to the acrylic acid ester is methacrylic acid ester / acrylic acid ester = 100/0 to 50/50. It is preferable.

As the impact modifier, as is used as the methacrylic acid ester and acrylic acid ester copolymer and a fluorine-based and (co) polymer was combined mixed, flame retardant auxiliary material (F), the average particle diameter 0 Inorganic particles of 0.5 to 15 μm are preferable, and as the appearance improving material (G), a hard (co) polymer containing a (meth) acrylic resin component is preferable.

  Another gist of the present invention resides in a molded article formed by molding such a flame-retardant polylactic acid-based thermoplastic resin composition of the present invention.

  In the present invention, “(meth) acrylic acid” is a general term for “acrylic acid” and “methacrylic acid”, and “hard (co) polymer” means “hard polymer (homopolymer)” and “hard copolymer”. It is a general term for “polymer”.

Further, in the present invention, acetone-soluble polylactic acid resin (A), aromatic polycarbonate resin (C), hard (co) polymer (b-2), and rubber-containing graft copolymer (b-1) described later are soluble in acetone. The weight-soluble molecular weight (Mw) of the minute, the acetone-soluble component of the hard (co) polymer (b-2), the appearance improving material (G), etc. are all determined by tetrahydrofuran (GPC) using tetrahydrofuran (GPC). What was measured by dissolving in THF) is shown in terms of polystyrene (PS).

  Since the flame-retardant polylactic acid-based thermoplastic resin composition of the present invention has a good balance of flame resistance, mechanical properties such as impact strength, heat resistance, and good appearance of a molded product obtained by molding this composition. It is a material suitable not only for electronic / electrical fields but also for other fields.

  According to the present invention, by providing a practical flame retardant polylactic acid-based thermoplastic resin composition as described above, the use of polylactic acid resin, which is a plant-based resin, is expanded, and the practice of the philosophy of carbon neutral is promoted. Therefore, it can contribute to the reduction of environmental load.

  Hereinafter, embodiments of the present invention will be described in detail.

[Polylactic acid resin (A)]
The polylactic acid resin (A) applied to the resin composition of the present invention can be obtained by known means such as a method of directly dehydrating condensation polymerization of lactic acid or a method of ring-opening polymerization of lactide.

  There are three types of optical isomers, L-form, D-form, and DL-form, in the polylactic acid resin, and commercially available polylactic acid resins have L-form purity close to 100%. The polylactic acid resin (A) used in (1) does not particularly define its purity, and may be a copolymer containing other copolymerization components as long as the effects of the present invention are not impaired.

  Other copolymerization components contained in the polylactic acid resin (A) include ethylene glycol, propylene glycol, butanediol, heptanediol, hexanediol, octanediol, nonanediol, decanediol, 1,4-cyclohexanedimethano -Glycol compounds such as diol, neopentyl glycol, glycerin, pentaerythritol, bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol; oxalic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid , Malonic acid, glutaric acid, cyclohexanedicarboxylic acid, terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, bis (p-carboxyphenyl) methane, anthracene dicarboxylic acid, 4, Dicarboxylic acids such as' -diphenyl ether dicarboxylic acid, 5-sodium sulfoisophthalic acid, 5-tetrabutylphosphonium isophthalic acid; hydroxycarboxylic acids such as glycolic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, hydroxybenzoic acid Examples include acids; lactones such as caprolactone, valerolactone, propiolactone, undecalactone, and 1,5-oxepan-2-one. The content of such a copolymer component is usually preferably 30 mol% or less and more preferably 10 mol% or less in all monomer components in the polylactic acid resin (A).

  The molecular weight and molecular weight distribution of the polylactic acid resin (A) are not particularly limited as long as it can be substantially molded, but the weight average molecular weight (Mw) is usually 10,000 or more, preferably 5 It is desirable that it is 10,000 or more, and 100,000 or more. Although there is no restriction | limiting in particular about the upper limit of the weight average molecular weight of a polylactic acid resin (A), Usually, it is 400,000 or less.

  The molecular weight can be measured by GPC (solvent THF: tetrahydrofuran), but when polylactic acid is in the form of pellets, it may be difficult to dissolve in THF. In that case, after dissolving in chloroform, The polymer component is precipitated using methanol, and the dried polymer component is dissolved in THF, and the molecular weight of the soluble component can be measured. Further, it can be dissolved by heating as necessary.

In the present invention, the blending amount of the polylactic acid resin (A) in the flame retardant polylactic acid-based thermoplastic resin composition is the sum of the polylactic acid resin (A), the rubber-reinforced resin (B), and the aromatic polycarbonate resin (C). The range of 10 to 50 parts by weight with respect to 100 parts by weight, preferably 10 to 45 parts by weight, more preferably 15 to 35 parts by weight, is a carbon neutral viewpoint and a point of improving impact resistance. Is preferable. If the blending amount of the polylactic acid resin (A) is less than this range, the object of the present invention for effectively using the polylactic acid resin cannot be achieved. A thermoplastic resin molded product cannot be obtained.

In addition, a polylactic acid resin (A) may be used individually by 1 type, and 2 or more types may be mixed and used for it.
Specific examples of such a polylactic acid resin include, for example, “Lacia” manufactured by Mitsui Chemicals, Inc., “Nature Works” manufactured by Cargill-Dow, “Ecology” manufactured by Mitsubishi Plastics, Inc., and the like. Can be used.

[Rubber reinforced resin (B)]
The rubber-reinforced resin (B) used in the present invention is preferably 30% to 95% by weight of a rubber-containing graft copolymer (b-1) obtained by graft-polymerizing a hard (co) polymer to a rubbery polymer. ) Polymer (b-2) in an amount of 5 to 70% by weight (a total of 100% by weight of (b-1) and (b-2)), and at least in the hard (co) polymer (b-2) ( It contains a (meth) acrylic resin component.

<Rubber-containing graft copolymer (b-1)>
The rubber-containing graft copolymer (b-1) used in the present invention is generally expressed by ABS, ASA, AES, MBS, etc., and has a structure in which a hard (co) polymer is graft-polymerized to a rubbery polymer. It is what you have.

  Examples of the rubbery polymer forming the rubber-containing graft copolymer (b-1) include butadiene rubbers such as polybutadiene, styrene / butadiene copolymer, acrylate ester / butadiene copolymer, and styrene / isoprene. Conjugated diene rubbers such as copolymers; Acrylic rubbers such as polybutyl acrylate; Olefin rubbers such as ethylene / propylene copolymers; Silicone rubbers such as polyorganosiloxane, etc. It can be used alone or in admixture of two or more. These rubbery polymers can be used from monomers, and the structure of the rubbery polymer may take a core / shell structure. For example, a rubbery polymer having polybutadiene as the core and acrylic acid ester as the shell can be used.

  The gel content of the rubbery polymer is preferably 50 to 99% by weight, more preferably 60 to 95% by weight, and particularly preferably 70 to 85% by weight. When the gel content is within this range, the properties of the obtained flame-retardant polylactic acid-based thermoplastic resin composition, particularly the impact strength, can be improved.

  In order to measure the gel content of the rubber polymer, specifically, the weighed rubber polymer was dissolved in an appropriate solvent at room temperature (23 ° C.) over 20 hours, and then 100 mesh. After separating with a wire mesh, the insoluble matter remaining on the wire mesh is dried at 60 ° C. for 24 hours and then weighed. The ratio (% by weight) of the insoluble matter with respect to the rubber polymer before fractionation is determined and used as the gel content of the rubber polymer. As the solvent used for dissolving the rubbery polymer, for example, toluene is used for polybutadiene and acetone is used for polybutyl acrylate.

  The particle size of the rubbery polymer is not particularly limited, but is preferably 0.1 to 1 μm, and more preferably 0.2 to 0.5 μm. The average particle size of the rubbery polymer can be measured by an optical method before graft polymerization. Further, after graft polymerization, the average particle diameter can be calculated using a transmission electron microscope (TEM) after dyeing the rubber polymer with a dyeing agent.

  The rubber-containing graft copolymer (b-1) is preferably obtained by graft polymerization of 60 to 20% by weight of the graft-polymerizable monomer component in the presence of 40 to 80% by weight of the above rubbery polymer. (However, the total of the rubbery polymer and the monomer mixture is 100% by weight). Here, if the rubber polymer is less than 40% by weight, the impact resistance of the obtained flame-retardant polylactic acid-based thermoplastic resin molded product cannot be obtained, and if it exceeds 80% by weight, impact resistance, fluidity, etc. There is a risk of lowering.

  Examples of monomer components capable of graft polymerization include vinyl cyanide monomers, aromatic vinyl monomers, methacrylic acid ester monomers, acrylic acid ester monomers, and maleimide compounds. Each monomer can be used alone or in combination of two or more.

Examples of the vinyl cyanide monomer include acrylonitrile and methacrylonitrile, and acrylonitrile is particularly preferable.
Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, bromostyrene, and the like, and styrene and α-methylstyrene are particularly preferable.
Examples of the methacrylic acid ester monomer include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, and derivatives thereof. Among these, methyl methacrylate is particularly preferable.
Examples of the acrylate monomer include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, and derivatives thereof. Among these, methyl acrylate is particularly preferable.
Examples of the maleimide compound include N-phenylmaleimide, N-cyclohexylmaleimide and the like.

  Moreover, the monomer modified | denatured by the functional group by the case may be included, for example, acrylic acid, methacrylic acid, itaconic acid, fumaric acid etc. are mentioned as unsaturated carboxylic acid. These can be used individually by 1 type or in mixture of 2 or more types. The proportion of use is preferably 30% by weight or less, particularly preferably 10% by weight or less, based on 100% by weight in the monomer mixture.

  The monomer component to be grafted of the rubber-containing graft copolymer (b-1) is preferably a vinyl cyanide monomer or an aromatic vinyl monomer among the above exemplified monomers. As the vinyl monomer, acrylonitrile is preferable, and as the aromatic vinyl monomer, styrene is particularly preferable from the viewpoint of further improving the impact resistance of the obtained flame-retardant polylactic acid-based thermoplastic resin molded article. In this case, the weight composition ratio of the vinyl cyanide monomer and the aromatic vinyl monomer is preferably in the range of 20/80 to 35/65, more preferably 25/75 to 30/70. Outside this range, dispersibility and thermal stability decrease.

  The weight-average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer (b-1) is preferably in the range of 50,000 to 600,000, more preferably 50,000 to 550,000, and still more preferably. It is in the range of 100,000 to 450,000. If the weight-average molecular weight of the acetone-soluble component is lower than this range, the resulting flame-retardant polylactic acid-based thermoplastic resin molded product will have insufficient impact resistance. The moldability of the lactic acid thermoplastic resin composition is reduced. The acetone-soluble component corresponds to a polymer product of a monomer that is not graft-polymerized to the rubbery polymer that is generated when the monomer is graft-polymerized to the rubbery polymer.

  The graft ratio of the rubber-containing graft copolymer (b-1) ((acetone insoluble matter weight / rubber polymer weight-1) × 100) is preferably 15 to 120% by weight, more preferably 20 to 85% by weight. Is more preferable. When the graft ratio is lower than 15% by weight, the dispersibility of the rubbery polymer is lowered and the impact strength is lowered. When the graft ratio is higher than 120% by weight, the impact strength and molding are reduced. Tend to decrease. The grafted copolymer may have a structure occluded not only inside but also inside the rubbery polymer.

  Graft polymerization can be carried out by known emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization, and may be a method combining these polymerization methods. As the rubber-containing graft copolymer (b-1), two or more kinds of rubber-containing graft copolymers having different polymerization methods and component compositions may be mixed and used.

<Hard (co) polymer (b-2)>
As a monomer component used for the hard (co) polymer (b-2) of the present invention, one or more of the monomers introduced in the above rubber-containing graft copolymer (b-1) are used. Can be used.
The weight average molecular weight of the hard (co) polymer (b-2) is preferably in the range of 30,000 to 300,000, and more preferably in the range of 50,000 to 250,000. When the weight average molecular weight of the hard copolymer (b-2) is lower than this range, the resulting flame-retardant polylactic acid-based thermoplastic resin molded article has insufficient impact resistance, and exceeds this range. In this case, the moldability is lowered.

  By blending the hard (co) polymer (b-2), characteristics such as heat resistance and fluidity can be improved, but the blending amount of the hard (co) polymer (b-2) is rubber-containing. If it exceeds 70% by weight with respect to the total of 100% by weight of the graft copolymer (b-1) and the hard (co) polymer (b-2), the rubber content in the rubber-reinforced resin (B) is reduced. As a result, the impact strength is reduced. For this reason, the compounding amount of the hard (co) polymer (b-2) is 100% by weight in total of the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2). 5 to 70% by weight, preferably 5 to 60% by weight, more preferably 5 to 50% by weight.

  Moreover, when mix | blending hard (co) polymer (b-2), the weight of acetone soluble part which match | combined the rubber-containing graft copolymer (b-1) and hard (co) polymer (b-2). The average molecular weight is in the range of 50,000 to 600,000, particularly in the range of 50,000 to 550,000, in particular 100,000, as shown in the description of the rubber-containing graft copolymer (b-1). A range of 450,000 is preferred. If the weight-average molecular weight of the acetone-soluble component is lower than this range, the resulting flame-retardant polylactic acid-based thermoplastic resin molded product will have insufficient impact resistance. The moldability of the lactic acid thermoplastic resin composition is reduced.

  In addition, a hard (co) polymer (b-2) may be used individually by 1 type, and may mix and use 2 or more types of a different composition and molecular weight.

<Rubber content>
In the present invention, the rubber content in the rubber-reinforced resin (B), that is, the rubber weight in the mixture of the rubber-containing graft copolymer (b-1) and the hard (co) polymer (b-2). It is preferable to adjust the coal content to be in the range of 5 to 80% by weight, particularly 10 to 70% by weight. If the content of the rubbery polymer in the rubber reinforced resin (B) is lower than this range, sufficient impact resistance cannot be obtained, and if it exceeds this range, the impact strength is reduced. . The content of the rubbery polymer in the rubber reinforced resin (B) can be measured by using an infrared spectrometer.

<(Meth) acrylic resin component>
The (meth) acrylic resin component is preferably contained in the hard (co) polymer (b-2) of the rubber-reinforced resin (B) used in the present invention in a proportion of 20 to 100% by weight. As described above, the (meth) acrylic resin component is contained in the hard (co) polymer (b-2) rather than the graft component of the rubber-containing graft copolymer (b-1). The improvement effect is more effectively exhibited.

  Thus, by using the hard (co) polymer (b-2) containing a (meth) acrylic resin component, the rubber-reinforced resin (B) used in the present invention contains a (meth) acrylic resin. It is preferable that the component is contained in an amount of 5 to 70% by weight, particularly 5 to 60% by weight, particularly 5 to 50% by weight. If the content of the (meth) acrylic resin component in the rubber reinforced resin (B) is less than 5% by weight, the effect of improving the impact resistance by blending the rubber reinforced resin (B) can be sufficiently exerted. Can not. Further, if the (meth) acrylic resin component in the rubber-reinforced resin (B) exceeds 70% by weight, impact resistance and moldability are lowered, which is not preferable.

As the (meth) acrylic resin component, a polymerization component of a methacrylic ester monomer such as methyl methacrylate, or an acrylate monomer such as methyl methacrylate monomer and methyl acrylate and / or A copolymerization component with other copolymerizable monomers is preferable, but the weight ratio of each monomer of methacrylic acid ester and acrylic acid ester is preferably 100/0 to 50/50, and more preferably 99/1 to A range of 80/20 is preferred. When the amount of acrylic ester exceeds this range, the thermal stability and heat resistance of the flame-retardant polylactic acid-based thermoplastic resin composition obtained tend to be impaired.
In addition, as a specific example of the monomer of methacrylic acid ester and acrylic acid ester, what is demonstrated by the impact modifier (D) mentioned later is used, but methyl methacrylate is acrylic acid as a methacrylic acid ester. It is preferable to use methyl acrylate as the acid ester.

  Examples of other monomers capable of co-polymerization include those introduced as monomer components capable of graft polymerization, and maleimide compounds and maleic anhydride are particularly preferred for the purpose of improving heat resistance. Etc. can be used. These monomers can be used alone or in combination of two or more.

  Specific examples of the copolymer of methyl methacrylate and methyl acrylate include, for example, “Parapet G” manufactured by Kuraray Co., Ltd., “Acrypet VH”, “Acrypet” manufactured by Mitsubishi Rayon Co., Ltd. MD ”and the like. Therefore, by blending these in the flame-retardant polylactic acid-based thermoplastic resin composition of the present invention as a hard (co) polymer (b-2), the rubber-reinforced resin (B) A (meth) acrylic resin component can be contained.

<Blending amount>
In the present invention, the blending amount of the rubber reinforced resin (B) in the flame retardant polylactic acid-based thermoplastic resin composition is the sum of the polylactic acid resin (A), the rubber reinforced resin (B), and the aromatic polycarbonate resin (C). Although it is in the range of 5 to 35 parts by weight with respect to 100 parts by weight, preferably 5 to 30 parts by weight, more preferably 5 to 25 parts by weight, in view of carbon neutral and improvement in impact resistance. It is preferable in terms. If the blending amount of the rubber reinforced resin (B) is less than this range, it is not preferable because the impact resistance is deteriorated and the appearance is inferior.

[ Aromatic polycarbonate resin (C)]
The weight average molecular weight of the aromatic polycarbonate resin are use in the present invention (C) (Mw) is preferably 10,000 to 50,000, in particular the range of 13,000～40,000. When the weight average molecular weight (Mw) of the aromatic polycarbonate resin (C) is lower than this range, the impact resistance tends to decrease, and when it exceeds this range, the fluidity is deteriorated and the moldability is inferior. Product appearance tends to be inferior.

Said aromatic polycarbonate resin may be used individually by 1 type, or may mix and use 2 or more types.

In this invention, the compounding quantity of aromatic polycarbonate resin (C) in a flame-retardant polylactic acid-type thermoplastic resin composition is polylactic acid resin (A), rubber reinforced resin (B), and aromatic polycarbonate resin (C). Although it is in the range of 45 to 85 parts by weight with respect to 100 parts by weight in total, it is preferably 50 to 85 parts by weight, more preferably 55 to 80 parts by weight, from the viewpoint of carbon neutral, impact resistance and difficulty. It is preferable in terms of improving the flame resistance and heat resistance. If the blending amount of the aromatic polycarbonate resin (C) is larger than this range, the object of the present invention for effectively using the polylactic acid resin cannot be achieved, and if it is less, the impact resistance, flame retardancy and heat resistance are excellent. A flame-retardant polylactic acid-based thermoplastic resin molded article cannot be obtained.

[Impact modifier (D)]
In the present invention, examples of the impact modifier (D) include those obtained by copolymerization or mixing of a methacrylic acid ester, an acrylic acid ester copolymer, and a fluorine-based (co) polymer. Among these, in the case of copolymerization, for example, there is a method of emulsion polymerization while adding a methacrylic acid ester or an acrylic acid ester to a fluorine-based (co) polymer. In the case of a mixture of a methacrylic acid ester, an acrylic acid ester copolymer and a fluorine-based (co) polymer, the mixing method includes latex and latex blend, latex and powder blend, beads and latex blend, A blend of beads and powder can be mentioned, and a latex blend is more preferable.
Specific examples of such an impact modifier (D) include, for example, commercially available “Maybrene A-3000” and “Metbrene A-3800” manufactured by Mitsubishi Rayon Co., Ltd.

  Examples of the acrylate ester include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, n-hexyl acrylate, n-heptyl acrylate, N-octyl acrylate, 2-ethylhexyl acrylate, nonyl acrylate, decyl acrylate, dodecyl acrylate, stearyl acrylate, and the like, acrylate aliphatic hydrocarbon (e.g., alkyl having 1 to 18 carbon atoms) ester; cyclohexyl acrylate Acrylic acid alicyclic hydrocarbon esters such as isobornyl acrylate; Acrylic aromatic hydrocarbon esters such as phenyl acrylate and toluyl acrylate; Aralkyl acrylates such as benzyl acrylate; 2-methoxyethyl acrylate Esters of acrylic acid such as 3-methoxybutyl acrylate and functional group-containing alcohols having etheric oxygen; trifluoromethyl methyl acrylate, 2-trifluoromethyl ethyl acrylate, 2-perfluoroethyl ethyl acrylate, acrylic 2-perfluoroethyl-2-perfluorobutylethyl acid, 2-perfluoroethyl acrylate, perfluoromethyl acrylate, diperfluoromethyl methyl acrylate, 2-perfluoromethyl-2-perfluoroethyl methyl acrylate And fluorinated alkyl acrylates such as 2-perfluorohexylethyl acrylate, 2-perfluorodecylethyl acrylate, 2-perfluorohexadecylethyl acrylate, and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

  Examples of the methacrylate ester include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-pentyl methacrylate, n-hexyl methacrylate, n-heptyl methacrylate, N-octyl methacrylate, 2-ethylhexyl methacrylate, nonyl methacrylate, decyl methacrylate, dodecyl methacrylate, stearyl methacrylate, and the like, methacrylic acid aliphatic hydrocarbon (eg, alkyl having 1 to 18 carbon atoms) ester; cyclohexyl methacrylate , Methacrylic acid alicyclic hydrocarbon esters such as isobornyl methacrylate; methacrylic acid aralkyl esters such as benzyl methacrylate; methacrylic acid aroma such as phenyl methacrylate and toluyl methacrylate Hydrocarbon esters; esters of methacrylic acid such as 2-methoxyethyl methacrylate and 3-methoxybutyl methacrylate with functional group-containing alcohols having etheric oxygen; trifluoromethyl methyl methacrylate, 2-trifluoromethyl ethyl methacrylate 2-perfluoroethylethyl methacrylate, 2-perfluoroethyl-2-perfluorobutylethyl methacrylate, 2-perfluoroethyl methacrylate, perfluoromethyl methacrylate, diperfluoromethyl methyl methacrylate, methacrylic acid 2 -Methacrylates such as perfluoromethyl-2-perfluoroethylmethyl, 2-perfluorohexylethyl methacrylate, 2-perfluorodecylethyl methacrylate, 2-perfluorohexadecylethyl methacrylate An acid fluorinated alkyl esters.

  Fluorine (co) polymers include ethylene difluoride polymers, ethylene trifluoride polymers, tetrafluoroethylene polymers, vinylidene fluoride polymers, tetrafluoroethylene / hexafluoropropylene copolymers, etc. Among these, a tetrafluoroethylene polymer is preferable, and the number average molecular weight (Mn) is 500,000 or more, for example, 600,000 to 10,000,000 is a balance between impact property and fluidity. Is preferred. The molecular weight can be calculated from the standard specific gravity.

  The ratio of methacrylic acid ester and acrylic acid ester of the methacrylic acid ester / acrylic acid ester copolymer constituting the impact modifier (D) is as follows: methacrylic acid ester: acrylic acid ester = 1: 0 to 1 (weight ratio) It is preferable that If the amount of acrylic acid ester is larger than this range and the amount of methacrylic acid ester is small, impact resistance is lowered and thermal stability is inferior.

  The ratio of the methacrylic acid ester / acrylic acid ester copolymer and the fluorine-based (co) polymer is as follows: methacrylic acid ester / acrylic acid ester copolymer: fluorinated (co) polymer = 1: 0.1 4 (weight ratio) is preferable. If there is more methacrylic acid ester / acrylic acid ester copolymer than this range and there are few fluorine-type (co) polymers, there will be little impact-modifying effect, and also flammability will fall, and conversely fluorine-type (co) polymers If the amount of the methacrylic acid ester / acrylic acid ester copolymer is small, the fluidity is deteriorated and the appearance is deteriorated. Moreover, combustibility is also reduced.

In this invention, the compounding quantity of the impact modifier (D) in a flame-retardant polylactic acid-type thermoplastic resin composition is polylactic acid resin (A), rubber reinforced resin (B), and aromatic polycarbonate resin (C). Although it is in the range of 0.1 to 8 parts by weight with respect to 100 parts by weight in total, it is preferably 0.1 to 5 parts by weight, more preferably 0.5 to 5 parts by weight. Is preferable. If the blending amount of the impact modifier (D) is less than this range, the impact resistance reforming effect is not manifested, and if it is greater, there are problems in moldability, molded product appearance, and the like.

[Flame Retardant (E)]
The flame retardant (E) that can be used in the present invention is not particularly limited as long as it imparts flame retardancy. Phosphorus flame retardant, bromine flame retardant, nitrogen flame retardant and inorganic flame retardant A flame retardant selected from the flame retardants can be used alone or in admixture of two or more.

  Examples of the phosphorus-based flame retardant used in the present invention include red phosphorus and phosphorus compounds. Examples of the phosphorus compound include phosphine, phosphine oxide, bisphosphine, phosphonium salt, phosphinate, phosphate ester, and phosphite ester. Etc. Of these, phosphate ester-based flame retardants are preferred in that there is no problem of mold contamination or generation of corrosive gas during molding. Examples of the phosphate ester flame retardant include a phosphate ester compound represented by the following general formula (I) and a condensed phosphate ester compound represented by the following general formula (II).

（（Ｉ）式中、Ｒ¹、Ｒ²およびＲ³は、それぞれ相互に独立して選ばれる炭素数１〜８のアルキル基、またはアルキル置換されていても良い炭素数６〜２０のアリール基を表し、ｎは０または１である。）

(In the formula (I), R ¹ , R ² and R ³ are each independently an alkyl group having 1 to 8 carbon atoms or an aryl group having 6 to 20 carbon atoms which may be alkyl-substituted) And n is 0 or 1.)

（（II）式中、Ｒ⁴、Ｒ⁵、Ｒ⁶およびＲ⁷は、それぞれ相互に独立して選ばれるアリール基またはアルカリール基を表し、Ｘはアリーレン基を表し、ｊ、ｋ、ｌ、およびｍは、それぞれ相互に独立して０または１である。Ｎは１〜５の整数であるが、リン酸エステル化合物の混合物の場合は、Ｎは平均値（１≦Ｎ≦５）を表す。）

(In the formula (II), R ⁴ , R ⁵ , R ⁶ and R ⁷ each independently represent an aryl group or an alkaryl group, X represents an arylene group, j, k, l, And m are each independently 0 or 1. N is an integer of 1 to 5, but in the case of a mixture of phosphate ester compounds, N represents an average value (1 ≦ N ≦ 5). .)

  Specific examples of the phosphoric acid ester compound represented by the general formula (I) include bis- (phenyl) -methyl phosphate, bis- (ethyl) -phenyl phosphate, bis- (ethyl) -2,6-dimethylphenyl. Phosphate, bis- (phenyl) -ethyl phosphate, bis- (phenyl) -butyl phosphate, bis- (neopentyl) -phenyl phosphate, bis- (4-methylphenyl) -2-ethylhexyl phosphate, bis- (2-ethylhexyl) -Phenyl phosphate, bis- (phenyl) -2-ethylhexyl phosphate, bis- (phenyl) -octyl phosphate, bis- (octyl) phenyl phosphate, bis- (3,5,5-trimethylhexyl) phenyl phosphate, bis- ( 2,5,5-trimethyl Xyl) -4-methylphenyl phosphate, bis- (phenyl) -isodecyl phosphate, bis- (dodecyl) -4-methylphenyl phosphate, bis- (dodecyl) phenyl phosphate, tris- (phenyl) phosphate, tris- (2 -Methylphenyl) phosphate, tris- (4-methylphenyl) phosphate, bis- (2-methylphenyl) phenyl phosphate, bis- (4-methylphenylphenyl) phenyl phosphate, bis- (phenyl) -2-methylphenyl phosphate Bis- (phenyl) -4-methylphenyl phosphate, tris- (isopropylphenyl) phosphate, bis- (isopropylphenyl) phenyl phosphate, bis- (phenyl) -isopropylphenyl phosphate, Lis- (nonylphenyl) phosphate, tris- (2,6-dimethylphenyl) phosphate, bis- (2,6-dimethylphenyl) phenyl phosphate, bis- (2,6-dimethylphenyl) -2,6-dimethylphenyl Phosphate, bis- (2,6-dimethylphenyl) -4-t-butylphenyl phosphate, bis- (2,6-dimethylphenyl) -4-methylphenyl phosphate, bis- (2,6-dimethylphenyl) -3 -Methylphenyl phosphate, bis- (2,6-dimethylphenyl) -4-isopropylphenyl phosphate, bis- (2,6-dimethylphenyl) -2-isopropylphenyl phosphate, and these are used alone. Or two or more of them may be used in combination.

Moreover, the condensed phosphate ester compound represented by the general formula (II) may be used alone or in combination of two or more. Therefore, in the said general formula (II), the value of N does not necessarily need to be an integer, and in the case of a mixture, it represents the average value in the mixture of a condensed phosphate ester compound. In the general formula (II), R ⁴ , R ⁵ , R ⁶ and R ⁷ are preferably cresyl group, phenyl group, xylenyl group, propylphenyl group, butylphenyl group, and the arylene group of X is, for example, resorcinol, It may be a group derived from hydroquinone, bisphenol A and dihydroxy compounds such as chlorinated compounds and brominated compounds thereof, or may be a phenylene group.

  As the phosphoric flame retardant, the above phosphoric acid ester compound and the condensed phosphoric acid ester may be used in combination.

  The brominated flame retardant used in the present invention includes at least one flame retardant selected from brominated epoxy polymers. The brominated epoxy polymer refers to an addition polymer of a brominated bisphenol compound and epichlorohydrin or a brominated bisphenol compound diglycidyl ether. Here, examples of the brominated bisphenol compound include tetrabromobisphenol A, dibromobisphenol A, tetrabromobisphenol F, and tetrabromobisphenol S. The molecular weight of the brominated epoxy polymer ranges from several hundred to several tens of thousands depending on the degree of polymerization (the number of repetitions of brominated bisphenol compound and 2-hydroxypropane unit). The molecular end of the brominated epoxy polymer may be an epoxy group or may be modified with an aryl group or an alkyl group, and these aryl group or alkyl group may be substituted with bromine. Examples of the aryl group include a phenyl group, a xylyl group, and a tribromophenyl group. Examples of the alkyl group include a methyl group, an ethyl group, and a tribromoneopentyl group.

  Specific examples of the brominated epoxy polymer include tetrabromobisphenol A / epoxy polymer and tribromophenol-modified tetrabromobisphenol A / epoxy polymer.

  Examples of the nitrogen-based flame retardant used in the present invention include aromatic amine compounds, aliphatic amine compounds, aromatic amides, aliphatic amides, and nitrogen-containing heterocyclic compounds. Examples of the aromatic amine include aniline and phenylenediamine. Examples of the aliphatic amine include ethylamine, butylamine, ethylenediamine, triethylenetetramine, and 1,2-diaminocyclohexane. Examples of aromatic amides include N, N-diphenylacetamide. Examples of the aliphatic amide include N, N-dimethylacetamide. Examples of the nitrogen-containing heterocyclic compound include adenine, guanine, uric acid, melamine, melamine cyanate, melamine isocyanate, and triazine compound.

  Examples of the inorganic flame retardant used in the present invention include magnesium hydroxide, aluminum hydroxide, antimony trioxide, antimony pentoxide, zinc stannate, tin oxide, zinc sulfate, ferrous oxide, zinc borate, boric acid. Ammonium, a zirconium compound, a guanidine compound, etc. are mentioned.

In this invention, the compounding quantity of the flame retardant (E) in a flame retardant polylactic acid-type thermoplastic resin composition is a total of 100 of polylactic acid resin (A), rubber reinforced resin (B), and aromatic polycarbonate resin (C). Although it is in the range of 0.1 to 25 parts by weight with respect to parts by weight, preferably 0.1 to 22 parts by weight, more preferably 5 to 22 parts by weight, flame retardancy, impact resistance, heat resistance From the viewpoint of sex. If the blending amount of the flame retardant (E) is less than this range, sufficient flame retardancy will not be exhibited, and if it is large, problems will arise in heat resistance, impact resistance and the like.

[Flame retardant auxiliary material (F)]
Examples of the flame retardant auxiliary material (F) that can be used in the present invention include inorganic particles such as talc and mica, and preferably inorganic particles such as talc and mica that have been surface-treated with a silane coupling agent.
In the case of inorganic particles surface-treated with a silane coupling agent, the coating amount of the silane coupling agent is usually 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on the base particles. is there. As the silane coupling agent, one having a functional group such as an epoxy group, an amino group, a vinyl group, or a hydroxyl group can be used. As this functional group, an epoxy group or an amino group is preferable.

  By using such a flame retardant auxiliary material (F), flame retardancy, particularly high flame retardancy, can be imparted without impairing mechanical properties and heat resistance. As the flame retardant auxiliary material (F), talc, particularly talc surface-treated with a silane coupling agent is particularly preferable.

The flame retardant auxiliary material (F) used in the present invention has an effect of assisting in flame retardancy, particularly high flame retardancy, by uniformly dispersing in the flame retardant polylactic acid-based thermoplastic resin composition. Demonstrate. Accordingly, the preferred average particle diameter is 0.5 to 15 μm, preferably 1 to 15 μm, more preferably 1.3 to 13 μm. When the average particle size of the flame retardant auxiliary material (F) is less than 0.5 μm, it tends to agglomerate when kneaded into the resin, so that not only the appearance of the molded product is lowered but also the flame retardancy is stabilized. To lose. When the average particle diameter exceeds 15 μm, not only the physical properties such as impact resistance are deteriorated, but also the stabilization of flame retardancy is impaired.
The particle size of the flame retardant auxiliary material (F) can be measured by a sedimentation method, a laser diffraction method, or the like, but is particularly easy to perform the laser diffraction method.

  The blending ratio of the flame retardant auxiliary material (F) is preferably in the range of 0.1 to 60 parts by weight with respect to 100 parts by weight in total of the polylactic acid resin (A) and the flame retardant (E), but more preferably. Is preferably from 30 to 30 parts by weight, particularly preferably from 3 to 25 parts by weight, in terms of flame retardancy and mechanical properties. If the blending amount of the flame retardant auxiliary material (F) is less than this range, a sufficient flame retardant auxiliary effect cannot be obtained, and if it is large, there is a problem in impact resistance.

[Appearance improving material (G)]
Examples of the appearance improving material (G) that can be used in the present invention include a hard (co) polymer containing a (meth) acrylic resin component. By using such a hard (co) polymer, weld lines and flow marks can be improved, and the appearance of the molded product can be remarkably improved.

  The appearance improving material (G) preferably contains 60 to 100% by weight of the (meth) acrylic resin component, and the (meth) acrylic resin component in the appearance improving material (G) is contained. As the constituting monomer, methacrylic acid ester and / or acrylic acid ester are preferable. Specific examples of the methacrylic acid ester and the acrylic acid ester include those exemplified as the methacrylic acid ester and the acrylic acid ester as constituents of the impact modifier (D), and one or more of them are used. be able to.

  Furthermore, it is preferable to contain 0 to 40% by weight of other resin components in the appearance improving material (G). Examples of other monomer components constituting the resin component include vinyl cyanide monomers, aromatic vinyl monomers, and maleimide compounds. Examples of vinyl cyanide monomers include acrylonitrile and methacrylonitrile. Among them, acrylonitrile is particularly preferable. Examples of the aromatic vinyl monomer include styrene, α-methylstyrene, p-methylstyrene, bromostyrene, and the like, and styrene and α-methylstyrene are particularly preferable. Examples of the maleimide compound include N-phenylmaleimide, N-cyclohexylmaleimide and the like. These monomer components can be used singly or in combination of two or more.

  The weight average molecular weight (Mw) of the appearance improving material (G) is preferably 50,000 to 300,000, particularly preferably 100,000 to 200,000. When the weight average molecular weight (Mw) of the appearance improving material (G) is lower than this range, the impact property is lowered, and when it exceeds this range, the fluidity is deteriorated and the appearance tends to be inferior.

The blending ratio of the appearance improving material (G) in the flame-retardant polylactic acid-based thermoplastic resin composition of the present invention is preferably 100 parts by weight in total of the polylactic acid resin (A) and the aromatic polycarbonate resin (C). 1 to 18 parts by weight, more preferably 1 to 12 parts by weight, particularly preferably 3 to 12 parts by weight, from the viewpoint of impact resistance and heat resistance. If the blending amount of the appearance improving material (G) is less than this range, a sufficient improvement in the appearance of the molded product is not observed, and if it is too large, problems arise in heat resistance, impact resistance and the like.

[Other ingredients]
The flame retardant polylactic acid-based thermoplastic resin composition of the present invention includes the polylactic acid resin (A), rubber-reinforced resin (B), aromatic polycarbonate resin (C), impact modifier (D), flame retardant ( In addition to E) and the flame retardant auxiliary material (F) and the appearance improving material (G) blended as necessary, various additives and other resins can be blended. In this case, various additives include known antioxidants, ultraviolet absorbers, lubricants, plasticizers, stabilizers, mold release agents, antistatic agents, colorants (pigments, dyes, etc.), carbon fibers, glass fibers, One type or two or more types of fillers such as wollastonite, calcium carbonate and silica, anti-drip agents, antibacterial agents, anti-fungal agents, silicone oils and coupling agents may be mentioned.

  Other resins include rubber-reinforced styrene resins such as HIPS resin, ABS resin, ASA resin, AES resin, AS resin, polystyrene resin, polyacetal resin, nylon resin, methacrylic resin, polyvinyl chloride resin, Examples include polyphenylene ether resin. Also, a blend of two or more of these may be used, and the above resin modified with a compatibilizer or a functional group may be blended.

[Production and molding of polylactic acid-based thermoplastic resin composition]
The method for pelletizing the flame retardant polylactic acid-based thermoplastic resin composition of the present invention is not particularly limited, and for example, a twin-screw extruder, a Banbury mixer, a heating roll, etc. can be used. Melt kneading by an extruder is preferable, and if necessary, resin and other additives can be blended by side feed or the like.

  The flame-retardant polylactic acid-based thermoplastic resin composition of the present invention can be molded into various molded products by ordinary molding methods such as injection molding, blow molding, sheet molding, and vacuum molding. In particular, injection molding is preferred.

  Although there is no restriction | limiting in particular as a use of the obtained molded article, The electric / electronic field, an automobile field, an optical field, a building material field etc. are mentioned, Especially suitable for the use as various housing | casings and structural members, such as an electronic / electric field. Can be used.

  In addition, the molded product formed by molding the flame-retardant polylactic acid-based thermoplastic resin composition of the present invention has good secondary decorating properties such as painting, plating and vapor deposition, and secondary workability such as welding and cutting. Yes, it can be expanded to wider fields and members.

  In addition, when preparing each component of the flame-retardant polylactic acid-based thermoplastic resin composition of the present invention, or when mixing, kneading, or molding these components, the resin waste, etc. is left as it is or when Can be crushed and subjected to a melt regeneration process. In this case, it can be recovered during molding, but it can also be recovered separately and used as a raw material in the above-described pellet manufacturing process.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to synthesis examples, examples, and comparative examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
In the following, “part” means “part by weight”.

The weight average molecular weight was measured by a standard PS (polystyrene) conversion method using Tosoh Co., Ltd. product: GPC (gel permeation chromatography, solvent; THF).
The average particle diameter of the rubber polymer was determined by a dynamic light scattering method using Nikkiso Co., Ltd .: Microtrac Model: 9230UPA.
The weight composition ratio of the monomer was determined using FT-IR manufactured by Horiba Ltd.

[Polylactic acid resin]
Polylactic acid resin (a-1): biodegradable polymer (L-form / D-form = 98/2 (weight ratio),
(Weight average molecular weight = 140,000, melting point = 171 ° C.)

[Rubber reinforced resin]
[Rubber-containing graft copolymer (b-1)]
Synthesis Example 1: Production of rubber-containing graft copolymer (b-1-1) A rubber-containing graft copolymer was synthesized by the emulsion polymerization method with the following composition.
[Combination]
Styrene (ST) 25 parts Acrylonitrile (AN) 10 parts Polybutadiene latex 65 parts (as solids)
Disproportionated potassium rosinate 1 part Potassium hydroxide 0.03 part Tertiary decyl mercaptan (t-DM) 0.04 part Cumene hydroperoxide 0.3 part Ferrous sulfate 0.007 part Sodium pyrophosphate 0.1 Part Crystalline glucose 0.3 part Distilled water 190 part

  An autoclave is charged with distilled water, disproportionated potassium rosinate, potassium hydroxide and polybutadiene latex (gel content 80% by weight, average particle size 0.3 μm), heated to 60 ° C., ferrous sulfate, sodium pyrophosphate Crystalline glucose was added and ST, AN, t-DM and cumene hydroperoxide were continuously added over 2 hours while maintaining the temperature at 60 ° C., and then the temperature was raised to 70 ° C. and maintained for 1 hour to complete the reaction. . An antioxidant was added to the ABS latex obtained by this reaction, then coagulated with sulfuric acid, sufficiently washed with water, and dried to obtain an ABS graft copolymer (b-1-1).

Synthesis Example 2: Production of rubber-containing graft copolymer (b-1-2) In the raw material formulation of Synthesis Example 1, polybutadiene (average particle size 0.3 μm) 50 having a gel content of 97% by weight as a rubbery polymer. The graft polymerization was carried out in the same manner as in Synthesis Example 1 except that 37 parts of styrene and 13 parts of acrylonitrile were reacted as a monomer using a part (as a solid content), and an ABS graft copolymer (b-1- 2) was obtained.

Synthesis Example 3: Production of rubber-containing graft copolymer (b-1-3) In the raw material formulation of Synthesis Example 1, polybutyl acrylate (gel content 65%, average particle size 0.34 μm) 60 was used as the rubbery polymer. Graft polymerization was performed in the same manner as in Synthesis Example 1 except that 36 parts of methyl methacrylate (MMA) and 4 parts of methyl acrylate (MA) were reacted as a monomer. A polymer (b-1-3) was obtained.

The rubber content, the weight composition ratio of the monomer, the graft ratio, and the weight-average molecular weight of the acetone-soluble component of the rubber-containing graft copolymer produced in Synthesis Examples 1, 2, and 3 were measured. there were.
Rubber-containing graft copolymer (b-1-1): rubber content = 66.2% by weight
AN / ST = 28/72
Graft ratio = 40% by weight
Weight average molecular weight (Mw) = 154,000
Rubber-containing graft copolymer (b-1-2): rubber content = 52.4% by weight
AN / ST = 26/74
Graft ratio = 57% by weight
Weight average molecular weight (Mw) = 145,000
Rubber-containing graft copolymer (b-1-3): rubber content = 62.3 wt%
MMA / MA = 90/10
Graft ratio = 35% by weight
Weight average molecular weight (Mw) = 70,000

The following commercially available products were used as the rubber-containing graft copolymer (b-1-4).
Rubber-containing graft copolymer (b-1-4): “Metablene S-20” manufactured by Mitsubishi Rayon Co., Ltd.
01 "(rubber polymer (made of silicone / butyl acrylate
Composite rubber) is graft polymerized with methyl methacrylate, etc.
Copolymer. Rubber content = approx. 65% by weight)

[Hard (co) polymer]
Synthesis Example 4: Production of Rigid (Co) polymer (b-2-1) A rigid (co) polymer was synthesized by suspension polymerization as follows.
In a nitrogen-substituted reactor, 120 parts of water, 0.002 part of sodium alkylbenzene sulfonate, 0.5 part of polyvinyl alcohol, 0.3 part of azoisobutylnitrile, 0.5 part of t-DM, 25 parts of acrylonitrile, 25 parts of styrene, A monomer mixture consisting of 50 parts of methyl methacrylate was used, and after heating at a starting temperature of 60 ° C. for 5 hours while gradually adding a portion of styrene, it was allowed to reach 120 ° C. Furthermore, after reacting at 120 ° C. for 4 hours, the polymer was taken out to obtain a hard (co) polymer (b-2-1).

Synthesis Example 5: Production of hard (co) polymer (b-2-2) Polymerization was conducted in the same manner as in Synthesis Example 4 except that a monomer mixture consisting of 98 parts of methyl methacrylate and 2 parts of methyl acrylate was added. To obtain a hard (co) polymer (b-2-2).

Synthesis Example 6 Production of Hard (Co) polymer (b-2-3) A monomer mixture consisting of 79 parts of methyl methacrylate, 1 part of methyl acrylate, and 20 parts of N-phenylmaleimide (NPMI) was added. Except for this, polymerization was carried out in the same manner as in Synthesis Example 4 to obtain a hard (co) polymer (b-2-3).

Synthesis Example 7: Production of hard (co) polymer (b-2-4) A monomer mixture consisting of 25 parts of acrylonitrile and 75 parts of styrene was used, except that a portion of styrene was added sequentially. Polymerization was conducted in the same manner as in Example 4 to obtain a hard (co) polymer (b-2-4).

When the weight composition ratio and weight average molecular weight (Mw) of the monomers of the hard (co) polymer produced in Synthesis Examples 4, 5, 6, and 7 were measured, they were as follows.
Hard (co) polymer (b-2-1): AN / ST / MMA = 25/25/50
Weight average molecular weight (Mw) = 113,000
Hard (co) polymer (b-2-2): MMA / MA = 98/2
Weight average molecular weight (Mw) = 136,000
Hard (co) polymer (b-2-3): MMA / MA / NPNI = 79/1/20
Weight average molecular weight (Mw) = 170,000
Hard (co) polymer (b-2-4): AN / ST = 25/75
Weight average molecular weight (Mw) = 150,000

The following polycarbonate resin was used as the aromatic polycarbonate resin (C).
Aromatic polycarbonate resin (c-1): “Panlite L-12” manufactured by Teijin Chemicals Ltd.
25L "
(Weight average molecular weight (Mw) 19,000)
Aromatic polycarbonate resin (c-2): made by Mitsubishi Engineering Plastics Co., Ltd.
"Iupilon S-3000"
(Weight average molecular weight (Mw) 23,000)

The impact modifier (D) was prepared as follows.
<Preparation of impact modifier (d-1)>
In the raw material composition of Synthesis Example 1, the rubbery polymer was not used, and except that 96 parts of methyl methacrylate (MMA) and 4 parts of methyl acrylate (MA) were reacted as monomers, Similarly, an emulsified MMA / MA copolymer was obtained (solid content: 40% by weight).
Next, this emulsified MMA / MA copolymer and emulsified polytetrafluoroethylene (Asahi Glass Co., Ltd. “FLUON AD1” solid content 60 wt%, number average molecular weight 3 million) of 50:50 in terms of solid content Mix in proportion and warm to 60 ° C. with thorough stirring. Thereafter, a 20% by weight sulfuric acid aqueous solution was gradually added and solidified while stirring, and the resulting solid content was dehydrated and dried to obtain an impact modifier (d-1).

As the flame retardant (E), the following were used.
Flame retardant (e-1): Brominated flame retardant “EC-20” manufactured by Dainippon Ink Co., Ltd.
Flame retardant (e-2): Phosphoric ester flame retardant “FP-500” manufactured by Asahi Denka Kogyo Co., Ltd.

The following materials were used as the flame retardant auxiliary material (F).
Flame retardant auxiliary material (f-1): “TP-A25” manufactured by Fuji Talc Kogyo Co., Ltd. (average particle diameter 5.1 μm by laser diffraction method) 100 parts by weight of epoxy silane (A-187) made of NUC silicone What was surface-treated with 1 part by weight was designated as a flame retardant auxiliary material (f-1).

  The appearance improving material (G) was synthesized by the suspension polymerization method as follows.

Synthesis Example 8 Production of Rigid (Co) polymer (b-2-5) 120 parts of water, 0.002 part of sodium alkylbenzene sulfonate, 0.5 part of polyvinyl alcohol, azoisobutyl nitrile Using a monomer mixture consisting of 3 parts, 0.5 parts t-DM, 12 parts acrylonitrile, 28 parts styrene, and 60 parts methyl methacrylate, a starting temperature of 60 ° C. to 5 ° C. was added while part of the styrene was added sequentially. After heating at elevated temperature, the temperature reached 120 ° C. Furthermore, after reacting at 120 ° C. for 4 hours, the polymer was taken out to obtain a hard (co) polymer (b-2-5).

The weight composition ratio and weight average molecular weight (Mw) of the monomer of the hard (co) polymer (b-2-5) produced in Synthesis Example 8 were measured and were as follows.
Hard (co) polymer (b-2-5): AN / ST / MMA = 12/28/60
Weight average molecular weight (Mw) = 113,000

[Production and evaluation of flame retardant polylactic acid-based thermoplastic resin composition pellets]
Each of the above components was mixed at the blending ratio shown in Table 1, and further mixed with 0.3 part of “Carbodilite HMV-8CA” manufactured by Nisshinbo Co., Ltd. as a stabilizer, followed by biaxial extrusion at 200 to 240 ° C. A pellet of a flame-retardant polylactic acid-based thermoplastic resin composition was prepared by melting and mixing with a machine (“TEX-30α” manufactured by Nippon Steel Works) and pelletizing.

These resin pellets were molded at 220-250 ° C. with a 2 ounce injection molding machine (manufactured by Toshiba Corporation), and the impact resistance (Charpy impact strength), flexural modulus, and heat resistance (load deflection temperature) were as follows: Measured by the method.
Charpy impact strength (KJ / m): ISO 179 (normal temperature)
Flexural modulus (MPa): ISO 178 (normal temperature)
Deflection temperature under load (° C.): ISO 75 (measurement load 1.82 MPa)

  Moreover, about combustibility, it molded at 220-250 degreeC using a 2 ounce injection molding machine (made by Toshiba Corporation), produced a 1.5 mm-thickness test piece, and performed a combustion test according to UL94. The flammability was investigated.

  As for the surface appearance of the molded product, visually observe the surface of the molded product, x indicates that there is a flow mark and the appearance is poor, x indicates that there is a weld line, etc. No appearance was judged as 外 観.

[Examples , Reference Examples and Comparative Examples]
Table 1 shows Examples 1 to 5 , 7 , Reference Examples 1 and 2 and Comparative Examples 1 to 4.

[Discussion]
As is apparent from Table 1, the flame-retardant polylactic acid-based thermoplastic resin compositions of Examples 1 to 5 and 7 that satisfy the requirements of the present invention have mechanical strength such as practically sufficient impact strength, heat resistance, It has flame retardancy and appearance, and in particular, it has an excellent balance of impact resistance, heat resistance, and flame retardancy.
In contrast, the polylactic acid resin alone of Comparative Example 1 has low impact strength. Even in the case where an aromatic polycarbonate resin is added, Comparative Example 2 which does not contain a rubber-reinforced resin and an impact modifier has low impact resistance and heat resistance, easily produces weld lines and flow marks, and the appearance is not good. In Comparative Examples 3 and 4 that do not contain an impact modifier, the impact resistance is low and the flame retardancy is not sufficient in terms of advanced electrical and electronic matters, compared to Examples 1 to 5 and 7. It is inferior to the physical property balance of the resin.

  Molded articles formed by molding the flame-retardant polylactic acid-based thermoplastic resin composition of the present invention have excellent mechanical strength such as impact resistance, flame resistance, and heat resistance, and are particularly excellent in heat resistance. The cycle can be shortened and the moldability is excellent, and the secondary decoration and secondary workability such as painting and vapor deposition are also excellent. In addition, it has an excellent appearance. For example, in applications related to electricity and electronics, it meets the needs of the market, such as notebook computers, mobile phones, printers, TVs, audio equipment and other office automation equipment, and exterior materials for home appliances. It can be used for a wide variety of purposes, and its industrial utility is very high, and it is also effective in reducing environmental impact.

Claims (7)

10 to 50 parts by weight of the polylactic acid resin (A), 5 to 35 parts by weight of the following rubber-reinforced resin (B), and 45 to 85 parts by weight of the aromatic polycarbonate resin (C) so as to be 100 parts by weight in total. Furthermore, with respect to a total of 100 parts by weight of the polylactic acid resin (A), the rubber-reinforced resin (B), and the aromatic polycarbonate resin (C), 0.1 to 8 parts by weight of the following impact modifier (D) A flame retardant polylactic acid-based thermoplastic resin composition comprising 0.1 to 25 parts by weight of a flame retardant (E).
Rubber-reinforced resin (B): rubber-containing graft copolymer (b-1) obtained by graft-polymerizing a hard (co) polymer to a rubbery polymer, wherein the rubbery polymer is an acrylic rubber, A rubber reinforced resin containing a (meth) acrylic resin component in a hard (co) polymer,
Or a rubber-containing graft copolymer (b-1) obtained by graft-polymerizing a hard (co) polymer to a rubbery polymer, wherein the rubbery polymer is a butanediene rubber; and (meth) rigid (co) polymer containing an acrylic resin component (b-2) consisting of a rubber-reinforced resin impact modifier (D): a copolymer of acrylic and methacrylic acid esters, fluorine-based Mixed with (co) polymer   Furthermore, 0.1-60 weight part of flame retardant auxiliary materials (F) are included with respect to a total of 100 weight part of a polylactic acid resin (A) and a flame retardant (E). Flame retardant polylactic acid-based thermoplastic resin composition.   The rubber-reinforced resin (B) contains 30 to 95% by weight of the rubber-containing graft copolymer (b-1) and 5 to 70% by weight of the hard (co) polymer (b-2) ((b-1) And (b-2) in total is 100% by weight). The flame-retardant polylactic acid-based thermoplastic resin composition according to claim 1 or 2,   The difficulty according to any one of claims 1 to 3, wherein the content of the (meth) acrylic resin component in the hard (co) polymer (b-2) is 20 to 100% by weight. A flame-retardant polylactic acid-based thermoplastic resin composition.   The monomer constituting the (meth) acrylic resin component contains a methacrylic acid ester and optionally an acrylic acid ester, and the weight ratio of the methacrylic acid ester to the acrylic acid ester is methacrylic acid ester / acrylic acid ester = 100/0. The flame-retardant polylactic acid-based thermoplastic resin composition according to any one of claims 1 to 4, wherein the composition is 50/50.   6. The flame retardant polylactic acid-based thermoplastic resin composition according to claim 2, wherein the flame retardant auxiliary material (F) is inorganic particles having an average particle diameter of 0.5 to 15 μm. .   A molded product formed by molding the flame-retardant polylactic acid-based thermoplastic resin composition according to any one of claims 1 to 6.