JPWO2017179564A1 - Styrenic resin composition and molded body using the same - Google Patents

Abstract

Without impairing the usefulness of each of the styrenic resin and polylactic acid, the styrenic resin composition that is excellent in mechanical strength and can be used as a food packaging material, etc. A molded product obtained by molding is provided. A styrene resin composition containing an impact-resistant styrene resin (A), a styrene-acrylate copolymer (B), and a polylactic acid (C), wherein the impact-resistant styrene resin (A ) And styrene-acrylic acid ester copolymer (B) in a total of 100 parts by mass, 1 to 5 parts by mass of polylactic acid (C) is blended, and the styrene-based resin composition.

Description

  The present invention relates to a styrene-based resin composition containing a styrene-based resin and polylactic acid from which a molded body excellent in mechanical strength can be obtained, and a molded body formed by molding the same.

  In recent years, it has also been recognized by general consumers that the use of plastic products containing various biodegradable polymers is preferable from the viewpoint of environmental protection and the use of plant-derived raw materials from the viewpoint of saving petroleum resources. Therefore, attempts to use biodegradable polymers and plant-derived polymers as raw materials have been widely applied to industrial products.

  In particular, polylactic acid is a plant-derived and biodegradable polymer, and among biodegradable polymers, it is practically superior because it has a relatively high melting point, toughness, transparency, and chemical resistance. Recognized as a polymer.

  On the other hand, the styrene resin is excellent in moldability and practical physical properties such as rigidity. In addition, a recycling system has been established for styrene resins, and the recycling rate is higher than other materials.

  From such a viewpoint, for example, studies have been made on blending a styrene resin and polylactic acid to ensure fluidity and improve mechanical properties (for example, see Patent Document 1). However, the compatibility between styrene-based resins and polylactic acid is very poor, and it is difficult to design products that take advantage of the physical properties required by the market and the characteristics of each resin by simply blending and melting and mixing.

JP 2008-50426 A

  In view of the above circumstances, the problem to be solved by the present invention is a molding that is excellent in mechanical strength and the like, and particularly suitable as a packaging material for foods, without impairing the usefulness of each of the styrene resin and polylactic acid. An object of the present invention is to provide a styrene resin composition capable of obtaining a body and a molded body obtained by thermoforming the composition.

  As a result of intensive research to solve the above-mentioned problems, the present inventors used an impact-resistant styrene resin and a styrene-acrylate copolymer as a styrene resin, and mixed polylactic acid in a specific amount. And the use of a styrene resin composition that is improved in impact resistance and elongation at break and can be suitably used as a packaging material, has led to the completion of the present invention.

  That is, the present invention is a styrenic resin composition containing an impact-resistant styrene resin (A), a styrene-acrylate copolymer (B), and polylactic acid (C), wherein the impact resistance Polystyrene (C) is blended in an amount of 1 to 5 parts by mass with respect to a total of 100 parts by mass of the styrene resin (A) and the styrene-acrylic acid ester copolymer (B). The present invention provides a resin composition and a molded body obtained by thermoforming the resin composition.

  The styrenic resin composition of the present invention has good mechanical strength of the resulting molded article, and can be suitably used particularly for food packaging applications.

  The impact-resistant styrenic resin (A) used in the present invention may be any polystyrene-based resin containing components such as rubber. For example, a rubber-like polymer is graft-polymerized on a continuous phase composed of a polymer of styrene alone. As the resin obtained by dispersing the particles, generally available resins can be used as they are. Examples of the rubber component contained in the impact-resistant styrene resin (A) include polybutadiene, styrene-butadiene copolymer, polyisoprene, and butadiene-isoprene copolymer. In particular, it is preferably contained as a polybutadiene or styrene-butadiene copolymer.

  The fluidity of the impact-resistant styrenic resin (A) used in the present invention is 1 to 10 g / 10 min. From the viewpoint of molding stability (thickness stability, molding processability). It is preferable that it exists in the range.

  Moreover, as a content rate of the said rubber-like polymer contained in an impact-resistant styrene-type resin (A), it is 1.5-15.0 mass% from a viewpoint of coexistence with impact strength and the processing characteristic at the time of stretch molding. It is preferable that As the impact-resistant styrene-based resin (A) having such characteristics, a commercially available product may be used as it is, as described above, and ordinary polystyrene is mixed with a resin having a high rubber component content. You may adjust and use the content rate and fluidity | liquidity of a rubber component in a suitable range.

  The styrene-acrylate copolymer (B) used in the present invention is a copolymer of a styrene monomer and an acrylate ester. The acrylic acid ester is preferably an acrylic acid alkyl ester, and more preferably an alkyl group having 1 to 20 carbon atoms. These may be used alone or in combination of two or more. Among these, it is preferable to use methyl acrylate, ethyl acrylate, and butyl acrylate, and it is more preferable to use butyl acrylate.

  The fluidity of the styrene-acrylic acid ester copolymer (B) used in the present invention is 1 to 10 g / 10 min. From the viewpoint of molding stability and kneadability. It is preferable that it exists in the range.

  Examples of the styrenic monomer include the following. Styrene and its derivatives; for example, styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, alkyl styrene such as octyl styrene, fluorostyrene, chlorostyrene , Halogenated styrene such as bromostyrene, dibromostyrene and iodostyrene, nitrostyrene, acetylstyrene, methoxystyrene and the like, which can be used alone or in combination of two or more. Further, a compound copolymerizable with the styrenic monomer (a1), for example, acrylonitrile, methacrylonitrile, maleic anhydride, maleimide, or a nucleus-substituted maleimide may be used in combination with the styrenic monomer.

  Further, it may be a styrene-acrylic acid ester copolymer having a branched structure formed by using a multi-branched macromonomer having a plurality of branches and having a plurality of polymerizable double bonds. By having a branched structure, it is possible to increase the molecular weight, and as a result, the mechanical strength of the obtained molded body can be further improved. As a result, the sheet obtained from the resin composition and the secondary molded product thereof can be thinned.

  As a use ratio of the multibranched macromonomer at this time, the multibranched macromonomer is obtained in a range of 100 to 2000 ppm as a mass ratio with respect to the total mass of the styrene monomer and the acrylate ester. The styrene-acrylic acid ester copolymer (B) is preferable from the viewpoint that the handling becomes good and the mechanical strength of the obtained molded body is excellent.

  The styrene-acrylic acid ester copolymer (B) used in the present invention is obtained by GPC when a multi-branched macromonomer having a plurality of branches and having a plurality of polymerizable double bonds is not used. The weight average molecular weight is preferably in the range of 100,000 to 400,000, and when the multibranched macromonomer is used in combination, the weight average molecular weight determined by the GPC-MALLS method is 150,000 to 700,000. Further, from the viewpoint of productivity and workability, it is more preferably in the range of 200,000 to 600,000. The styrene-acrylic acid ester copolymer (B) may be a single one or a mixture of a plurality of copolymers, and in the case of a mixture, the molecular weight of the mixture is in the above range. It is preferable that

[GPC-MALLS measurement]
The GPC-MALS measurement described above is performed under the conditions of Shodex HPLC, detector Wyatt Technology DAWN EOS, Shodex RI-101, column Shodex KF-806L × 2, solvent THF, and flow rate of 1.0 ml / min. is there. GPC-MALLS was analyzed using Wyatt's analysis software ASTRA. In addition to obtaining the weight average molecular weight of the styrene resin, the molecular weight of the resin obtained from GPC-MALLS was plotted on the horizontal axis and the inertial radius was plotted on the vertical axis. The slope in the region of molecular weight 250,000 to 10 million in the log-log graph with the axis (the slope of the approximate straight line automatically calculated by the software based on the measured value of only the linear portion obtained in the molecular weight range) )

[Multi-branched macromonomer]
As a multibranched macromonomer having a plurality of branches and having a plurality of polymerizable double bonds that can be used in the present invention, from the viewpoint of suppressing the generation of gel and ensuring fluidity, The macromolecular monomer having a weight average molecular weight (Mw) of preferably 1,000 to 15,000, more preferably 3,000 to 8,000 is used.

[GPC measurement]
The molecular weight of the hyperbranched macromonomer was measured by gel permeation chromatography (hereinafter abbreviated as “GPC”) using “HPLC 8010” manufactured by Tosoh Corporation, column Shodex KF802 × 2 + KF803 + KF804, solvent THF, flow rate 1.0 ml / The measurement was performed under the condition of min.

  The branched structure in the multi-branched macromonomer is not particularly limited, but a quaternary carbon atom in which all three bonds other than an electron withdrawing group and a bond to be bonded to the electron withdrawing group are bonded to a carbon atom. And those that form a branched structure by repeating structural units having an ether bond, an ester bond or an amide bond are preferred.

When the multibranched macromonomer forms a branched structure with the quaternary carbon, the electron withdrawing group content is 2.5 × 10 ⁻⁴ mmol to 5.5 g / g of the multibranched macromonomer. It is preferably in the range of 0 × 10 ⁻¹ mmol, more preferably in the range of 5.0 × 10 ⁻⁴ mmol to 5.0 × 10 ⁻² mmol.

  It is essential that the multi-branched macromonomer has two or more polymerizable double bonds per molecule. The content of the polymerizable double bond is preferably in the range of 0.1 to 5.5 mmol, and more preferably in the range of 0.5 to 3.5 mmol, per 1 g of the macromonomer. The polymerizable double bond is preferably present at the tip of the multi-branched macromonomer.

  The multi-branched macromonomer that can be used in the present invention includes a branched structure formed by repeating structural units having an ester bond, an ether bond or an amide bond, and two or more polymerizable double bonds in one molecule at the branch end. And a multi-branched macromonomer having

  A multi-branched macromonomer in which a structural unit having an ester bond is repeated to form a branched structure is a multi-branched polyester polyol in which the carbon atom adjacent to the carbonyl group of the ester bond forming the molecular chain is a quaternary carbon atom. A compound having a polymerizable double bond such as vinyl group or isopropenyl group introduced therein can be mentioned as a preferred embodiment. Introducing a polymerizable double bond into a multi-branched polyester polyol can be carried out by an esterification reaction or an addition reaction.

  In the multi-branched polyester polyol, a substituent may be introduced into a part of the hydroxy group in advance by an ether bond or other bond, and a part of the hydroxy group may be oxidized or other reaction. It may be denatured. Further, in the hyperbranched polyester polyol, a part of the hydroxy group may be esterified in advance.

  As the multi-branched macromonomer, for example, a compound having one or more hydroxy groups is reacted with a monocarboxylic acid having a quaternary carbon atom adjacent to a carboxy group and having two or more hydroxy groups. And a polymer obtained by reacting an unsaturated acid such as acrylic acid or methacrylic acid or an isocyanate group-containing acrylic compound with the hydroxy group which is the terminal group of the polymer. In addition, about the multibranched polymer which formed the branched structure by repeating the structural unit which has an ester bond, "Angew.Chem.Int.Ed.Engl.29" p138-177 (1990) by Mr. Tamalia etc. Have been described.

  Examples of the compound having at least one hydroxy group include a) aliphatic diol, alicyclic diol, or aromatic diol, b) triol, c) tetraol, d) sugar alcohols such as sorbitol and mannitol, e) anne Hydroenenea-heptitol or dipentaerythritol, f) α-alkyl glucoside such as α-methyl glycoside, g) monofunctional alcohol such as ethanol, hexanol, h) alkylene oxide having a weight average molecular weight of at most 8,000, or The hydroxy group containing polymer etc. which were produced | generated by making the derivative and the hydroxyl group in 1 or more types of compounds selected from any of said a) -g) react can be mentioned.

  Examples of the a) aliphatic diol, alicyclic diol and aromatic diol include, for example, 1,2-ethanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1, 6-hexanediol, polytetrahydrofuran, dimethylolpropane, neopentylpropane, 2-propyl-2-ethyl-1,3-propanediol, 1,2-propanediol, 1,3-butanediol, diethylene glycol, triethylene glycol , Polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol; cyclohexanedimethanol, 1,3-dioxane-5,5-dimethanol; 1,4-xylylenediethanol, 1-phenyl-1,2-ethanediol Etc. . Examples of the b) triol include trimethylolpropane, trimethylolethane, trimethylolbutane, glycerol, 1,2,5-hexanetriol, 1,3,5-trihydroxybenzene, and the like. Examples of c) tetraol include pentaerythritol, ditrimethylolpropane, diglycerol, and ditrimethylolethane.

  Examples of the monocarboxylic acid in which the carbon atom adjacent to the carboxyl group is a quaternary carbon atom and having two or more hydroxy groups include, for example, dimethylolpropionic acid, α, α-bis (hydroxymethyl) butyric acid, α , Α, α-tris (hydroxymethyl) acetic acid, α, α-bis (hydroxymethyl) valeric acid, α, α-bis (hydroxymethyl) propionic acid, and the like. By using the monocarboxylic acid, the ester decomposition reaction is suppressed and a multibranched polyester polyol can be formed.

  Further, it is preferable to use a catalyst when producing the multi-branched polyester polyol. Examples of the catalyst include organic tins such as dialkyltin oxide, halogenated dialkyltin, dialkyltin biscarboxylate, and stannoxane. Examples thereof include compounds, titanates such as tetrabutyl titanate, organic sulfonic acids such as Lewis acid and p-toluenesulfonic acid.

As a multi-branched macromonomer having a branched structure formed by repeating structural units having an ether bond, for example, a compound having at least one hydroxy group or a cyclic ether compound is reacted with a cyclic ether compound having at least one hydroxy group To form a multi-branched polymer, and then to the hydroxyl group which is the terminal group of the polymer, an unsaturated acid such as acrylic acid or methacrylic acid, an isocyanate group-containing acrylic compound, or a halogenated methylstyrene such as 4-chloromethylstyrene. Can be obtained by reacting. Further, as a method for producing the multi-branched polymer, a compound having one or more hydroxy groups, two or more hydroxy groups and a halogen atom, -OSO ₂ OCH ₃ or -OSO ₂ is based on Williamson's ether synthesis method. A method of reacting with a compound containing CH ₃ is also useful.

  As the compound having one or more hydroxy groups, any of those mentioned above can be used, and as the cyclic ether compound having one or more hydroxy groups, for example, 3-ethyl-3- (hydroxymethyl) Examples include oxetane, 2,3-epoxy-1-propanol, 2,3-epoxy-1-butanol, and 3,4-epoxy-1-butanol. The compounds having one or more hydroxy groups used in the Williamson ether synthesis method may be those described above, but aromatic compounds having two or more hydroxy groups bonded to an aromatic ring are preferred. Examples of the compound include 1,3,5-trihydroxybenzene, 1,4-xylylenediethanol, 1-phenyl-1,2-ethanediol and the like. Examples of the compound containing two or more hydroxy groups and a halogen atom, —OSO 2 OCH 3 or —OSO 2 CH 3 include 5- (bromomethyl) -1,3-dihydroxybenzene, 2-ethyl-2- (bromomethyl) -1 , 3-propanediol, 2-methyl-2- (bromomethyl) -1,3-propanediol, 2- (bromomethyl) -2- (hydroxymethyl) -1,3-propanediol, and the like. In addition, when manufacturing the said multi-branched polymer, it is preferable to use a catalyst normally, and examples of the catalyst include BF3 diethyl ether, FSO3H, ClSO3H, and HClO4.

  In addition, examples of the multi-branched macromonomer in which a structural unit having an amide bond is repeatedly formed to form a branched structure include those having a repeating structure having an amide bond via a nitrogen atom in the molecule. 2.0 (PAMAM dentrimer) is a typical one.

[Polymerization method of hyperbranched macromonomer with styrene monomer and acrylate ester]
When the hyperbranched macromonomer, styrenic monomer, acrylic ester, and other monomers used in combination are copolymerized as necessary, a hyperbranched resin and a linear resin that is simultaneously generated depending on the polymerization conditions And a resin mixture which is a mixture with a low-branched resin is obtained. At this time, the above-mentioned hyperbranched macromonomer is preferably used in a ratio of 50 ppm to 1%, more preferably 100 ppm to 2000 ppm (mass basis) with respect to the total amount of the other monomers. The resin can be easily produced, and the production of the styrene-acrylic acid ester copolymer (B) used in the present invention is facilitated.

  Various commonly used polymerization methods of styrene monomers can be applied to the polymerization reaction. The polymerization method is not particularly limited, but bulk polymerization, suspension polymerization, or solution polymerization is preferable. Among them, continuous bulk polymerization is particularly preferable from the viewpoint of production efficiency.For example, by performing continuous bulk polymerization incorporating one or more stirred reactors and a tubular reactor in which a plurality of mixing elements having no moving parts are fixed. An excellent resin can be obtained. Although thermal polymerization can be performed without using a polymerization initiator, it is preferable to use various radical polymerization initiators. Moreover, what is used for manufacture of a normal polystyrene can be used for polymerization adjuvants, such as a suspending agent and an emulsifier required for superposition | polymerization.

  In order to reduce the viscosity of the reaction product in the polymerization reaction, an organic solvent may be added to the reaction system. Examples of the organic solvent include toluene, ethylbenzene, xylene, acetonitrile, benzene, chlorobenzene, dichlorobenzene, and anisole. , Cyanobenzene, dimethylformamide, N, N-dimethylacetamide, methyl ethyl ketone and the like. In particular, when it is desired to increase the amount of the hyperbranched macromonomer, it is preferable to use an organic solvent from the viewpoint of suppressing gelation. Thereby, the addition amount of the multibranched macromonomer (a3) shown above can be dramatically increased to introduce a lot of branched structures, and gelation hardly occurs.

  The radical polymerization initiator is not particularly limited. For example, 1,1-bis (t-butylperoxy) cyclohexane, 2,2-bis (t-butylperoxy) butane, 2,2-bis (4 , 4-di-butylperoxycyclohexyl) propane and other peroxyketals, cumene hydroperoxide, hydroperoxides such as t-butyl hydroperoxide, di-t-butyl peroxide, dicumyl peroxide, di Dialkyl peroxides such as -t-hexyl peroxide, diacyl peroxides such as benzoyl peroxide and disinamoyl peroxide, t-butyl peroxybenzoate, di-t-butyl peroxyisophthalate, t-butyl peroxide Pao such as oxyisylpropyl monocarbonate Siesters, N, N′-azobisisobutylnitrile, N, N′-azobis (cyclohexane-1-carbonitrile), N, N′-azobis (2-methylbutyronitrile), N, N′-azobis ( 2,4-dimethylvaleronitrile), N, N′-azobis [2- (hydroxymethyl) propionitrile] and the like, and these can be used alone or in combination.

  Furthermore, you may add a chain transfer agent so that the molecular weight of the resin obtained may not become too large. As the chain transfer agent, either a monofunctional chain transfer agent having one chain transfer group or a polyfunctional chain transfer agent having a plurality of chain transfer groups can be used. Examples of the monofunctional chain transfer agent include alkyl mercaptans and thioglycolic acid esters. Polyfunctional chain transfer agents include ethylene glycol, neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, sorbitol and the like, the hydroxy group in thioglycolic acid or 3-mercaptopropionic acid And the like esterified with.

  In addition, long chain alcohols, polyoxyethylene alkyl ethers, polyoxyethylene lauryl ethers, polyoxyoleyl ethers, polyoxyethylene alkenyl ethers, and the like can be used to suppress gel formation of the resulting resin.

  In addition, a lubricant, an antistatic agent, an antioxidant, a heat stabilizer, an ultraviolet absorber, a dye, a plasticizer, and the like can be used as long as the physical properties of the obtained resin and molded article are not impaired.

  The polylactic acid (C) used in the present invention is obtained by, for example, saccharifying starch obtained from corn or potatoes, further obtaining lactic acid by lactic acid bacteria, and then cyclizing the lactic acid to form lactide. Generally available polylactic acid (C) obtained by ring polymerization can be used. Further, polylactic acid obtained by synthesizing lactide from petroleum and ring-opening polymerization thereof, or polylactic acid obtained by obtaining lactic acid from petroleum and directly dehydrating and condensing it may be used.

  In addition, the lactic acid constituting the polylactic acid (C) can be used by mixing L-lactic acid and D-lactic acid, but when the obtained composition is a molded body, the molded body has excellent heat resistance. From the above, it is preferable that the isomer is composed of either isomer of L-lactic acid or D-lactic acid. Specifically, the content of D isomer (ratio of D-lactic acid to the total mass of lactic acid used as a raw material) is 3. A content of 0.0% or less is preferable.

  Furthermore, other components may be copolymerized with polylactic acid (C) in addition to D-lactic acid and L-lactic acid, which are main constituent monomers. Examples of other copolymer components include ethylene glycol, propylene glycol, butanediol, oxalic acid, adipic acid, and sebacic acid. Such a copolymer component is preferably contained in an amount of generally 0 to 30 mol%, more preferably 0 to 10 mol%, in all monomer components.

  The molecular weight and molecular weight distribution of polylactic acid (C) are not particularly limited as long as it can be substantially molded, but the weight average molecular weight is preferably 10,000 to 400,000, more preferably 40,000 to 200,000. It is a range.

  It is also possible to add an additive for suppressing the thermal degradation of polylactic acid (C). Specific examples include carbodiimide and epoxy additives.

  The use ratio of the impact-resistant styrene resin (A), the styrene-acrylate copolymer (B), and the polylactic acid (C) is as follows: the impact-resistant styrene resin (A) and the styrene-acrylate ester By using 1 to 5 parts by mass of polylactic acid (C) with respect to 100 parts by mass in total with the copolymer (B), the resin composition has good dispersibility, and an easily molded article having excellent mechanical strength can be easily obtained. Can get to. More preferably, the polylactic acid (C) is in the range of 1 to 3 parts by mass with respect to 100 parts by mass in total of the impact-resistant styrene resin (A) and the styrene-acrylic acid ester copolymer (B). Furthermore, it is preferable that the mass ratio represented by (A) / (B) in the total of (A) and (B) is in the range of 60/40 to 90/10.

  Moreover, in this invention, although impact-resistant styrene resin (A), a styrene-acrylic acid ester copolymer (B), and polylactic acid (C) are used, other resin and various addition are as needed. A styrenic resin composition may be used in combination with an agent.

  Examples of the various additives include an antistatic agent, an antioxidant, an ultraviolet absorber, a lubricant, an antiblocking agent, and a heat stabilizer.

  The molded body of the present invention can be processed into a sheet and then subjected to secondary processing to form a molded body. At this time, the thickness of the sheet is not particularly limited, but it is in the range of 0.5 to 6.0 mm from the viewpoint of ease of handling when obtaining a molded body by secondary processing and strength as a molded body. It is preferable to make it become, and it is more preferable that it is the range of 0.75-3 mm.

  Also, the order of mixing the resins is not particularly limited. For example, after the dry blending of the impact-resistant styrene resin (A), the styrene-acrylate copolymer (B) and the polylactic acid (C), After preparing a master batch in which an impact-resistant styrene resin (A) and polylactic acid (C) were melt-kneaded in advance, this master batch, the impact-resistant styrene resin (A), and styrene-acrylic Examples thereof include a method of molding after melt-kneading the acid ester copolymer (B).

  In addition, if necessary, a method of melt-kneading other additives at the same time, or preparing a master batch in which an impact-resistant styrene resin (A) and other additives are melt-kneaded in advance, A method of melt-kneading and molding the impact styrene resin (A), the styrene-acrylate copolymer (B) and the polylactic acid (C) may be used.

  Moreover, it is preferable that the temperature at the time of melt-kneading each component is in the range of 180 to 260 ° C. From the viewpoint of preventing deterioration of polylactic acid (C) due to heat, polylactic acid (C) and impact-resistant styrene resin ( A) It is preferable that it is 180-230 degreeC from a kneadable viewpoint of a styrene-acrylic acid ester copolymer (B).

  The die temperature of a circular die, a T die, or the like when processed into a sheet shape is preferably in the range of 120 to 150 ° C. for stable sheet forming.

  The sheet obtained above can be subjected to secondary processing by thermoforming to form a molded body. As the thermoforming method, a hot plate contact heat forming method, a vacuum forming method, a vacuum / pressure forming method, a plug assist forming method and the like are preferably used.

  The shape of the molded body is not particularly limited, such as various packs, cases, etc., but is preferably for food packaging from the viewpoint of the mechanical strength and the like that are the characteristics of the styrenic resin composition of the present invention and the molded body, Use as a container tray or a container is particularly preferable.

  A film or sheet can be bonded to the front and back of the obtained sheet or a molded body obtained by secondary molding for the purpose of imparting improved mechanical strength and chemical resistance. Specifically, it is also possible to thermally laminate a polystyrene-based inflation film or to bond an olefin-based film (CPP) using an adhesive. It is also possible to laminate films and sheets simultaneously in an in-line foam molding.

  Moreover, it is also possible to obtain a molded body by injection molding using the styrene resin composition of the present invention as it is. The shape of the mold at this time is not particularly limited, and can be appropriately selected depending on the application. The temperature during injection molding is preferably in the range of 180 to 260 ° C., from the viewpoint of preventing deterioration of polylactic acid (C) due to heat, polylactic acid (C) and impact-resistant styrene resin (A), styrene -It is preferable that it is 180-230 degreeC from a kneadable viewpoint of the acrylic ester copolymer (B).

  EXAMPLES Hereinafter, although an Example is given and this invention is further demonstrated, this invention is not limited to these Examples at all. Unless otherwise indicated, both parts and% are based on mass.

〔Liquidity〕
The impact resistant styrene resin and styrene-acrylic acid ester copolymer were measured at 200 ° C. and 5 kg load, and the polylactic acid was measured at 210 ° C. and 2.16 kg load.

[Molding method]
Impact-resistant polystyrene (A), styrene-acrylic acid ester copolymer (B) and polylactic acid (C) were melt-kneaded with a twin-screw extruder (230 ° C.) to obtain a pellet-shaped sample. The obtained sample was molded by an injection molding machine (melting temperature 230 ° C.) to obtain a sample for evaluation (dumbbell shape).

  The mechanical properties of the obtained sample for evaluation were measured and evaluated by the following methods.

(Tensile fracture stress)
The sample for evaluation was measured with a tensile tester (Toyo Seiki) and evaluated according to the following evaluation criteria.
◎: 30 Mpa or more Δ: 20 Mpa or more and less than 30 Mpa ×: less than 20 Mpa

[Elongation at break]
The sample for evaluation was measured with a tensile tester (Toyo Seiki) and evaluated according to the following evaluation criteria.
◎: 35% or more △: 20% or more and less than 35% ×: less than 20%

[Bending strength]
The sample for evaluation was measured with a bending tester (Instron) and evaluated according to the following evaluation criteria.
A: 55 Mpa or more Δ: 50 Mpa or more and less than 55 Mpa ×: less than 50 Mpa

(Bending elastic modulus)
The sample for evaluation was measured with a bending tester (Instron) and evaluated according to the following evaluation criteria.
A: 2400 Mpa or more Δ: 2200 Mpa or more and less than 2400 ×: less than 2200 Mpa

[Charpy impact strength measurement test]
After the evaluation sample was cut to a predetermined size with a notching tool, the strength was measured with an impact tester (Toyo Seiki) and evaluated according to the following evaluation criteria.
A: 15 kJ / m ² or more Δ: 10 kJ / m ² or more and less than 15 kJ / m ² ×: less than 10 kJ / m ²

The following were used as impact-resistant styrene resin (A).
(A-1): Styrenic resin having a fluidity of 2.0 g / 10 min and a rubber component content of 7% in the resin (A-2): Fluidity of 4.0 g / 10 min, containing a rubber component in the resin Styrenic resin with an amount of 10% (A-3): Styrene resin with a fluidity of 10.0 g / 10 min and a rubber component content of 3% in the resin

The method for synthesizing the resin is as follows.
(A-1): 90 parts of styrene monomer, 10 parts of toluene, 6 parts of butadiene rubber, 300 ppm of t-butyl peroxybenzoate (monomer ratio), and 1.5 hours at 130 ° C. in a stirred reaction vessel The reaction was carried out at 140 ° C. to 180 ° C. for 3.5 hours. And purified by purification.

  (A-2): Under the conditions of (A-1), the above resin was obtained by synthesis under the same conditions except that the butadiene rubber was changed to 8 parts.

  (A-3): Under the conditions of (A-1), the above resin was obtained by synthesis under the same conditions except that butadiene rubber was changed to 2.5 parts.

Reference Example 1 Synthesis of Multibranched Macromonomer (Mm-1) <Synthesis of Multibranched Polyether Polyol 1>
To a 2 liter flask equipped with a stirrer, a thermometer, a dropping funnel and a condenser, 50.5 g of ethoxylated pentaerythritol (5 mol-ethylene oxide-added pentaerythritol) and 1 g of BF ₃ diethyl ether solution (50%) were added at room temperature. Heated to 110 ° C. To this, 450 g of 3-ethyl-3- (hydroxymethyl) oxetane was slowly added over 25 minutes while controlling the exotherm due to the reaction. When the exotherm had subsided, the reaction mixture was further stirred at 120 ° C. for 3 hours and then cooled to room temperature. The resulting multi-branched polyether polyol had a weight average molecular weight of 3,000 and a hydroxyl value of 530.

<Synthesis of Multibranched Polyether 1 Having Methacryloyl Group and Acetyl Group>
In a reactor equipped with a Dean-Stark decanter equipped with a stirrer, a thermometer, a condenser, and a gas introduction tube, 50 g of the multi-branched polyether polyol obtained in the above-mentioned <Synthesis of multi-branched polyether polyol 1>, methacrylic acid 13 .8 g, 150 g of toluene, 0.06 g of hydroquinone and 1 g of paratoluenesulfonic acid, and stirring under normal pressure while blowing 7% oxygen-containing nitrogen (v / v) into the mixed solution at a rate of 3 ml / min. Heated. The amount of heating was adjusted so that the amount of distillate in the decanter was 30 g per hour, and heating was continued until the amount of dehydration reached 2.9 g. After completion of the reaction, the mixture was cooled once, 36 g of acetic anhydride and 5.7 g of sulfamic acid were added, and the mixture was stirred at 60 ° C. for 10 hours. Thereafter, in order to remove the remaining acetic acid and hydroquinone, it was washed with 50 g of 5% aqueous sodium hydroxide solution four times, and further washed once with 50 g of 1% aqueous sulfuric acid solution and twice with 50 g of water. To the obtained organic layer, 0.02 g of methoquinone was added, the solvent was distilled off while introducing 7% oxygen-containing nitrogen (v / v) under reduced pressure, and 60 g of a multibranched polyether having an isopropenyl group and an acetyl group was obtained. Obtained. The weight average molecular weight of the obtained multibranched polyether was 3,900, and the introduction ratios of isopropenyl group and acetyl group into the multibranched polyether polyol were 30 mol% and 62 mol%, respectively.

Reference Example 2 Synthesis of Multibranched Macromonomer (Mm-2) <Synthesis of Multibranched Polyether Polyol 2>
In a 1000 mL three-necked flask connected with nitrogen, air reflux condenser, magnetic stir bar and thermometer, 1.24 g (8.7 mmol) of boron trifluoride diethyl ether complex was dried and the peroxide was removed. Dilute with 273 g of methyl-t-butyl ether. In a separate container, 140 g (1.21 mol) of 3-hydroxymethyl-3-ethyloxetane and 70.0 g (1.21 mol) of propylene oxide were mixed, and the above three-necked flask was consumed with a metering pump for 5.5 hours. And dripped. At this time, the system was cooled by an ice bath as needed to keep the temperature in the system at 20 ° C. After completion of the dropwise addition, 63.0 g (1.08 mol) of propylene oxide was further added dropwise over 3 hours while keeping the temperature in the system at 20 ° C., and the mixture was further stirred for 4 hours. Here, 0.620 g (4.4 mmol) of boron trifluoride diethyl ether complex was added, and the mixture was further stirred at 20 ° C. for 6 hours. The reaction mixture was adsorbed and removed by adding hydrotalcite 10 times the weight of boron trifluoride diethyl ether complex used in the reaction and refluxing for 1 hour. After the hydrotalcite was filtered off, methyl-t-butyl ether was removed to obtain 267 g of a transparent and highly viscous multi-branched polyether polyol. This multi-branched polyether polyol has Mn = 2,876 g / mol, Mw = 7,171 g / mol, hydroxyl value = 253 mg · KOH / g, and 3-hydroxymethyl-3-ethyl on a molar basis from proton NMR. Oxetane: propylene oxide = 1: 1.9.

<Synthesis of multi-branched polyether 2 having acryloyl group>
In a 500 mL four-necked flask equipped with a Dean-Stark tube, nitrogen and air introduction tube, a stirrer, and a thermometer, the multi-branched polyether polyol obtained in the above <Synthesis of multi-branched polyether polyol 2> 155 g, 51 g of acrylic acid, 200 g of cyclohexane, 0.21 g of hydroquinone monomethyl ether, and 4 g (12.3 mmol) of dodecylbenzenesulfonic acid as a catalyst were added, and the temperature was raised to 82 ° C. under a mixed gas flow of nitrogen and air 2 to 1. . Cyclohexane reflux began, and water flow began gradually. Thereafter, when the temperature was raised to 85 ° C. and reacted for 18 hours, 60% of the theoretical dehydration amount was reached, so cooling was started. After cooling to around 30 ° C., 5% sodium hydroxide aqueous solution and 15% NaCl aqueous solution were added for washing. The hydroxyl group value of the obtained polymerizable unsaturated group-containing multi-branched polyether was 70 mg · KOH / g, and the acrylic group introduction rate of all hydroxyl groups was 60%.

Reference Example 3 Synthesis of Multibranched Macromonomer (Mm-3) <Synthesis of Multibranched Polyether 1 Having Styryl Group and Acetyl Group>
In a reactor equipped with a stirrer, a condenser equipped with a drying tube, a dropping funnel and a thermometer, 50 g of the multibranched polyether polyol obtained in the above-mentioned <Synthesis of multibranched polyether polyol 1>, 100 g of tetrahydrofuran and sodium hydride 4.3 g was added and stirred at room temperature. To this was added dropwise 26.7 g of 4-chloromethylstyrene over 1 hour, and the resulting reaction mixture was further stirred at 50 ° C. for 4 hours. After completion of the reaction, the reaction mixture was once cooled, 34 g of acetic anhydride and 5.4 g of sulfamic acid were added, and the mixture was stirred at 60 ° C. for 10 hours. Thereafter, the tetrahydrofuran was distilled off under reduced pressure, the resulting mixture was dissolved in 150 g of toluene, washed with 50 g of 5% aqueous sodium hydroxide solution to remove the remaining acetic acid, and further 50 g of 1% aqueous sulfuric acid solution. And once with 50 g of water. The solvent was distilled off from the obtained organic layer under reduced pressure to obtain 70 g of a multi-branched polyether having a styryl group and an acetyl group. The obtained multi-branched polyether had a mass average molecular weight of 4,800, and the styryl group and acetyl group introduction rates into the multi-branched polyether polyol were 38 mol% and 57 mol%, respectively.

Reference Example 4 Synthesis of Multibranched Macromonomer (Mm-4) <Synthesis of Multibranched Macromonomer Having Methacryloyl Group and Acetyl Group>
A four-necked flask was equipped with a stirrer, pressure gauge, condenser and saucer, to which 308.9 g of ethoxylated pentaerythritol and 0.46 g of sulfuric acid were added. Then, it heated to 140 degreeC and 460.5g of 2, 2- di (hydroxymethyl) propionic acid was added over 10 minutes. After 2,2-di (hydroxymethyl) propionic acid is completely dissolved and becomes a transparent solution, the pressure is reduced to 30 to 40 mmHg and the reaction is continued for 4 hours while stirring and the acid value becomes 7.0 mgKOH / g. I let you. Thereafter, 921 g of 2,2-di (hydroxymethyl) propionic acid and 0.92 g of sulfuric acid were added to the reaction solution over 15 minutes to obtain a transparent solution, and then the pressure was reduced to 30 to 40 mmHg, while stirring. The polyester polyol was obtained by reacting for a period of time. In a reaction vessel equipped with a 7% oxygen introduction tube, a thermometer, a Dean-Stark decanter equipped with a condenser, and a stirrer, 10 g of the polyester polyol produced above, 1.25 g of dibutyltin oxide, and 100 g of methyl methacrylate having an isopropenyl group And 0.05 g of hydroquinone were added, and the mixture was heated with stirring while blowing 7% oxygen at a rate of 3 ml / min. The amount of heating is adjusted so that the amount of distillate in the decanter is 15 to 20 g per hour, the distillate in the decanter is taken out every hour, and the corresponding amount of methyl methacrylate is added for 4 hours. Reacted. After completion of the reaction, methyl methacrylate was distilled off under reduced pressure, and 10 g of acetic anhydride and 2 g of sulfamic acid were added to cap the remaining hydroxy groups, followed by stirring at room temperature for 10 hours. After removing sulfamic acid by filtration and distilling off acetic anhydride and acetic acid under reduced pressure, the residue was dissolved in 70 g of ethyl acetate and washed 4 times with 20 g of 5% aqueous sodium hydroxide to remove hydroquinone. Further, it was washed twice with 20 g of a 7% aqueous sulfuric acid solution and twice with 20 g of water. To the obtained organic layer, 0.0045 g of methoquinone was added, and the solvent was distilled off while introducing 7% oxygen under reduced pressure to obtain 11 g of a hyperbranched macromonomer (Mm-3) having an isopropenyl group and an acetyl group. It was. The resulting multi-branched macromonomer (Mm-3) has a weight average molecular weight of 3,000, a number average molecular weight of 2,100, and a double bond introduction amount of 2.00 mmol / g, an isopropenyl group and an acetyl group. The introduction rates were 55 mol% and 36 mol%, respectively.

Reference Example 5 Synthesis of hyperbranched macromonomer (Mm-5) <Synthesis of PAMAM dendrimer having a styryl group>
To a reactor equipped with a stirrer, a condenser equipped with a drying tube, a dropping funnel and a thermometer, 50 g of a methanol solution (20%) of PAMAM dendrimer (Generation 2.0: manufactured by Dentritech) was added and stirred under reduced pressure. Methanol was distilled off. Subsequently, 50 g of tetrahydrofuran and 3.0 g of finely divided potassium hydroxide were added, and the mixture was stirred at room temperature. 4-chloromethylstyrene 7.0g was dripped at this over 10 minutes, and the obtained reaction mixture was further stirred at 50 degreeC for 3 hours. After completion of the reaction, the mixture was cooled and the solid was filtered, and then tetrahydrofuran was distilled off under reduced pressure to obtain 13 g of a PAMAM dendrimer having a styryl group. The resulting styryl group content of the dendrimer was 2.7 mmol / gram.

Reference Example 6 Synthesis of Multibranched Macromonomer (Mm-6) <Multibranched Polyether Polyol 2 Having Styryl Group and Acetyl Group>
A light-shielding reaction vessel equipped with a stirrer, a condenser, a light-shielding dropping funnel and a thermometer, and capable of nitrogen sealing. Under nitrogen flow, anhydrous 1,3,5-trihydroxybenzene 0.5 g, potassium carbonate 29 g, 18-crown -6 2.7 g and acetone 180 g were added, and a solution composed of 21.7 g of 5- (bromomethyl) -1,3-dihydroxybenzene and 180 g of acetone was added dropwise over 2 hours while stirring. Thereafter, the mixture was heated and refluxed with stirring until 5- (bromomethyl) -1,3-dihydroxybenzene disappeared. Thereafter, 9.0 g of 4-chloromethylstyrene was added, and the mixture was further heated and refluxed with stirring until the disappearance. Thereafter, 4 g of acetic anhydride and 0.6 g of sulfamic acid were added to the reaction mixture, and the mixture was stirred overnight at room temperature. After cooling, the solid in the reaction mixture was removed by filtration, and the solvent was distilled off under reduced pressure. The obtained mixture was dissolved in dichloromethane and washed three times with water, and then the dichloromethane solution was added dropwise to hexane to precipitate a multibranched polyether. This was filtered and dried to obtain 12 g of a multi-branched polyether polyol having a styryl group and an acetyl group. The mass average molecular weight was 3,200, and the styryl group content was 3.5 mmol / gram.

(Reference Example 7) Synthesis of hyperbranched macromonomer (Mm-7) <Synthesis of hyperbranched polyester polyol having methacryloyl group and acetyl group>
In a reaction vessel equipped with a 7% oxygen introduction tube, a thermometer, a Dean-Stark decanter equipped with a condenser, and a stirrer, 10 g of “Boltorn H20”, 1.25 g of dibutyltin oxide, and isopropenyl group as a functional group (B) 100 g of methyl methacrylate and 0.05 g of hydroquinone were added, and the mixture was heated with stirring while blowing 7% oxygen at a rate of 3 ml / min. The amount of heating is adjusted so that the amount of distillate in the decanter is 15 to 20 g per hour, the distillate in the decanter is taken out every hour, and the corresponding amount of methyl methacrylate is added for 6 hours. Reacted.

  After completion of the reaction, methyl methacrylate was distilled off under reduced pressure, and 10 g of acetic anhydride and 2 g of sulfamic acid were added to cap the remaining hydroxy groups, followed by stirring at room temperature for 10 hours. After removing sulfamic acid by filtration and distilling off acetic anhydride and acetic acid under reduced pressure, the residue was dissolved in 70 g of ethyl acetate and washed 4 times with 20 g of 5% aqueous sodium hydroxide to remove hydroquinone. Further, it was washed twice with 20 g of a 7% aqueous sulfuric acid solution and twice with 20 g of water. To the obtained organic layer, 0.0045 g of methoquinone was added, and the solvent was distilled off while introducing 7% oxygen under reduced pressure to obtain 12 g of a hyperbranched polyester having an isopropenyl group and an acetyl group. The obtained multibranched polyester had a mass average molecular weight of 2860 and a number average molecular weight of 3770, and the introduction rates of isopropenyl group and acetyl group into the multibranched polyester polyol (A) were 55% and 40%, respectively.

Reference Example 8 Synthesis of Multibranched Macromonomer (Mm-8) <Synthesis of Solvent-Soluble Polyfunctional Vinyl Compound Copolymer>
3.1 mol (399.4 g) of divinylbenzene, 0.7 mol (95.1 g) of ethylvinylbenzene, 0.3 mol (31.6 g) of styrene, 2.3 mol (463.5 g) of 2-phenoxyethyl methacrylate Then, 974.3 g of toluene was put into a 3.0 L reactor, 42.6 g of boron trifluoride diethyl ether complex was added at 50 ° C., and reacted for 6.5 hours. After stopping the polymerization reaction with a sodium hydrogen carbonate solution, the oil layer was washed three times with pure water, and the reaction mixture was poured into a large amount of methanol at room temperature to precipitate a polymer. The obtained polymer was washed with methanol, filtered, dried, and weighed to obtain 372.5 g of a polyfunctional vinyl aromatic copolymer. The weight average molecular weight Mw of this polyfunctional vinyl copolymer is 8000, the molar fraction of the structural unit containing a vinyl group derived from a divinyl compound is 0.44, and the double bond derived from the terminal 2-phenoxyethyl methacrylate is 0. 0.03, the combined molar fraction of both was 0.47.

  The following were prepared as the multi-branched styrene-acrylic acid copolymer (B).

  Hyperbranched styrene-butyl acrylate copolymer (B-1): 95 parts of styrene monomer, 5 parts of butyl acrylate, 10 parts of toluene, 200 ppm (monomer ratio) of t-butyl peroxybenzoate, obtained in Reference Example 1 The obtained multibranched macromonomer (Mm-1) was added at 500 ppm (monomer ratio), and reacted in a stirred reaction tank at 120 ° C. for 1.5 hours and from 130 ° C. to 170 ° C. for 3.5 hours, unreacted Monomer and toluene at 230 ° C., vacuum degree 70-30 Torr. And purified by purification.

  Hyperbranched styrene-butyl acrylate copolymer (B-2): Except that the macromonomer was changed to Mm-2 obtained in Reference Example 2, it was the same as (B-1).

  Multi-branched styrene-butyl acrylate copolymer (B-3): Except that the macromonomer was changed to Mm-3 obtained in Reference Example 3, it was the same as (B-1).

  Multi-branched styrene-butyl acrylate copolymer (B-4): Except that the macromonomer was changed to Mm-4 obtained in Reference Example 4, it was the same as (B-1).

  Multi-branched styrene-butyl acrylate copolymer (B-5): Except that the macromonomer was changed to Mm-5 obtained in Reference Example 5, all were the same as (B-1).

  Multi-branched styrene-butyl acrylate copolymer (B-6): Except that the macromonomer was changed to Mm-6 obtained in Reference Example 6, all were the same as (B-1).

  Multi-branched styrene-butyl acrylate copolymer (B-7): Except that the macromonomer was changed to Mm-7 obtained in Reference Example 7, all were the same as (B-1).

  Multi-branched styrene-butyl acrylate copolymer (B-8): Except that the macromonomer was changed to Mm-8 obtained in Reference Example 8, all were the same as (B-1).

  Linear styrene-butyl acrylate copolymer (B): 95 parts of styrene monomer, 5 parts of butyl acrylate, 10 parts of toluene, and 200 ppm (monomer ratio) of t-butyl peroxybenzoate were added and stirred in a reaction tank. The reaction was carried out at 120 ° C. for 1.5 hours and at 130 ° C. to 170 ° C. for 3.5 hours. And purified by purification.

  Polylactic acid (C) has a fluidity of 10 g / 10 min. (190 ° C., 21.2 N), D-form: 1.4 mol%, weight average molecular weight: 180,000).

Example 1
Impact-resistant styrene resin (A-1) / multi-branched styrene-acrylic acid ester copolymer (B-1) / polylactic acid (C) = 70/30/2 parts are dry blended and a twin screw extruder Was melt-kneaded at 230 ° C. and then molded with an injection molding machine to obtain a sample for evaluation.

Example 2
An evaluation sample was obtained under the same conditions as in Example 1 except that the impact-resistant styrene resin was changed to (A-2).

Example 3
An evaluation sample was obtained under the same conditions as in Example 1 except that the impact-resistant styrene resin was changed to (A-3).

Example 4
Impact-resistant styrene-based resin (A-1) / multi-branched styrene-acrylic acid ester copolymer (B-1) / polylactic acid (C) = 70/30/3 parts are dry blended and a twin screw extruder Was melt-kneaded at 230 ° C. and then molded with an injection molding machine to obtain a sample for evaluation.

Example 5
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-2).

Example 6
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-3).

Example 7
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-4).

Example 8
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-5).

Example 9
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-6).

Example 10
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-7).

Example 11
An evaluation sample was obtained under the same conditions as in Example 1 except that the hyperbranched styrene-acrylic acid ester copolymer was changed to (B-8).

Example 12
Impact blending styrene resin (A-1) / linear styrene-acrylic acid ester copolymer (B) / polylactic acid (C) = 70/30/2 parts are dry blended using a twin screw extruder The mixture was melt-kneaded at 230 ° C. and then molded with an injection molding machine to obtain a sample for evaluation.

Comparative Example 1
Impact-resistant styrenic resin (A-1) / polylactic acid (C) = 100/2 parts are dry blended, melt kneaded at 230 ° C. using a twin-screw extruder, and then molded by an injection molding machine for evaluation. A sample was obtained.

Comparative Example 2
Impact blended styrene resin (A-1) / multi-branched styrene-acrylic acid ester copolymer (B-1) = 70/30 parts are dry blended and melt kneaded at 230 ° C. using a twin screw extruder. After that, it was molded by an injection molding machine to obtain a sample for evaluation.

Comparative Example 3
The impact-resistant styrene resin (A-1) was melt-kneaded at 230 ° C. using a twin-screw extruder and then molded with an injection molding machine to obtain a sample for evaluation.

  The evaluation results are shown in Tables 1-2.

Claims (9)

  A styrene resin composition comprising an impact resistant styrene resin (A), a styrene-acrylic acid ester copolymer (B), and a polylactic acid (C), the impact resistant styrene resin A styrene-based resin composition comprising 1 to 5 parts by mass of polylactic acid (C) with respect to a total of 100 parts by mass of (A) and a styrene-acrylic acid ester copolymer (B). .   The ratio of use of the impact-resistant styrene resin (A) and the styrene-acrylate copolymer (B) is 60/40 to 90/10 as a mass ratio represented by (A) / (B). The styrenic resin composition according to claim 1, which is in a range.   The styrenic resin composition according to claim 1 or 2, wherein the impact-resistant styrenic resin (A) is obtained by graft polymerization of a rubbery polymer on a continuous phase composed of a polymer of styrene alone.   The composition of the raw material of the styrene-acrylic acid ester copolymer (B) is in the range of 95/5 to 85/15 as a mass ratio represented by styrene monomer / acrylic acid ester. The styrenic resin composition according to any one of claims   The styrene-acrylic acid ester copolymer (B) further contains a multibranched macromonomer as a copolymerization component, and the multibranched macromonomer is in a mass ratio with respect to the total mass of the styrene monomer and the acrylic ester. The styrenic resin composition according to any one of claims 1 to 4, which is contained in a range of 100 to 2000 ppm.   The styrene resin composition according to any one of claims 1 to 5, wherein the acrylate ester of the styrene-acrylate copolymer (B) is butyl acrylate.   The styrene resin composition according to claim 3, wherein the content of the rubber-like polymer in the impact-resistant styrene resin (A) is in the range of 1.5 to 15% by mass.   The molded object which is a molded article of the styrene resin composition in any one of Claims 1-7.   The molded product according to claim 8, which is used for food packaging.