JP6206711B2 - Styrenic resin composition and method for producing the same - Google Patents

Description

  The present invention relates to a styrene resin composition containing a styrene resin, polylactic acid, and epoxidized oil.

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

  In particular, polylactic acid is a plant-derived and biodegradable polymer, and among the 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. Therefore, studies have been made to make use of the characteristics of these resins. For example, studies have been made on blending a specific 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. Patent Document 1 describes that compatibility can be improved by using a styrene resin composed of a copolymer of an aromatic vinyl monomer and an unsaturated carboxylic acid compound in combination with a general-purpose styrene resin. However, the fluidity and mechanical properties of the composition do not reach practical levels, and further improvements are required.

JP 2008-050427 A

  In view of the above circumstances, the problem to be solved by the present invention is to provide a styrenic resin composition using these in combination without impairing the usefulness of the styrenic resin and polylactic acid.

  As a result of intensive studies to solve the above problems, the present inventors solved a dispersibility failure by containing a styrene-methacrylic acid copolymer, other styrene resin, polylactic acid, and epoxidized oil. The inventors have found that a styrenic resin composition excellent in moldability, strength, heat resistance, oil resistance, and the like can be provided, and have completed the present invention.

  That is, the present invention provides a styrene-based resin composition and a production method comprising a styrene-methacrylic acid copolymer, polylactic acid, epoxidized oil, and a styrene-based resin other than the styrene-methacrylic acid copolymer. Is.

  The styrenic resin composition of the present invention has good moldability, mechanical strength, oil resistance, and the like. Moreover, it can reduce an environmental load by mix | blending a plant-derived resin, and can also be used for various general purpose molded objects, and is preferable from a viewpoint of environmental protection.

The present invention is described in detail below.
The styrene-methacrylic acid copolymer (A) used in the present invention is a copolymer of a styrene monomer and methacrylic acid, and the copolymerization type may be block or random. From the viewpoint of dispersibility (compatibility) with polylactic acid (B) described later, the content ratio derived from the methacrylic acid component is preferably 2 to 20% by mass, and more preferably 5 to 15% by mass. . Examples of styrenic monomers include 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, octyl styrene, and other alkyl styrenes. , Halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene, and further nitrostyrene, acetylstyrene, methoxystyrene, and the like. These may be used alone or in combination of two or more. Among these, it is preferable to use a styrene monomer from the viewpoint of excellent versatility.

  The fluidity of the styrene-methacrylic acid copolymer (A) used in the present invention is 1 to 20 g / 10 min. It is preferable to be in the range of (230 ° C., 37.3 N).

  The polylactic acid (B) used in the present invention is obtained by, for example, saccharifying starch obtained from corn, potatoes, etc., further obtaining lactic acid by lactic acid bacteria, and then cyclizing the lactic acid to form lactide. Generally available polylactic acid (B) obtained by ring polymerization can be used. Also, 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.

  The lactic acid constituting the polylactic acid can also be used by mixing L-lactic acid and D-lactic acid. However, from the viewpoint of excellent heat resistance of the molded product when the resulting composition is used as a molded product, L -It is preferable that it consists of any one isomer of lactic acid or D-lactic acid. Specifically, the D isomer content rate (ratio of D-lactic acid to the total mass of lactic acid used as a raw material) is 3.0%. The following are preferred.

  Furthermore, other components may be copolymerized with polylactic acid (B) 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 (B) 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.

  Although the oil component used for the epoxy modification of the epoxidized oil (C) is not particularly limited, it is naturally derived from the viewpoint that the composition obtained in the present invention can be suitably used as a food packaging material. It is preferably an oil component, and examples include animal oils such as beef tallow, pork tallow and fish, and vegetable oils.

  Vegetable oil is mainly composed of fatty acid triglyceride, which is a triester (triglyceride) between fatty acid and glycerin, and unsaturated fatty acid (carbon--) such as oleic acid, linolenic acid and linoleic acid as the fatty acid component. A fatty acid having a carbon double bond in the main chain). This carbon-carbon bond can generally be easily epoxidized using peracids (percarboxylic acids) or other peroxy compounds.

  Examples of vegetable oils include dry oils such as dehydrated castor oil, tung oil, linseed oil, sunflower oil, rosehip oil, coconut oil, and semi-dry oils such as soybean oil, rapeseed oil, safflower oil, cottonseed oil, sesame oil, and corn oil. It is done. Among these, linseed oil or soybean oil is preferable. That is, the epoxidized vegetable oil is preferably epoxidized linseed oil obtained by epoxy-modifying linseed oil or epoxidized soybean oil obtained by epoxy-modifying soybean oil. Linseed oil and soybean oil are highly stable as starting materials, and also have a relatively large number of carbon-carbon double bonds in the structure.

  As the epoxidized oil, commercially available ones can be used as they are. For example, as epoxidized soybean oil, “ADEKA SIZER O-130P” manufactured by ADEKA Corporation, “New Sizer 510R” manufactured by NOF Corporation, Kapo Co., Ltd. “Capox S-6”, DIC Corporation “Epocizer W-100-EL”, etc., ADEKA Co., Ltd. “Adeka Sizer O-180A” as an epoxidized linseed oil, NOF Corporation “New Sizer” 512 "," Eposizer W-109 "manufactured by DIC Corporation, and the like.

  As the styrene resin (D) other than the styrene methacrylic acid copolymer used in the present invention, a homopolymer of a styrene monomer or a vinyl monomer copolymerizable with a styrene monomer (excluding methacrylic acid) Examples thereof include a copolymer and a rubber-modified styrene resin.

  Examples of the styrenic monomer include, in addition to styrene, α-methylstyrene, α-methyl-p-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, ethylstyrene, isobutyl. Examples include styrene, and t-butyl styrene or bromostyrene, chlorostyrene, and indene. In particular, it is preferable to use a styrene homopolymer.

  Examples of the vinyl monomer copolymerizable with the styrene monomer (excluding methacrylic acid) include various acrylic esters and multi-branched macro monomers provided in JP-A No. 2003-292707.

  Examples of the rubber-modified styrenic resin include a resin in which rubbery polymer particles are dispersed in a styrenic resin matrix, and the aforementioned styrenic monomer is polymerized in the presence of the rubbery polymer. Can be manufactured.

  As the rubbery polymer, for example, polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like can be used, but polybutadiene or styrene-butadiene copolymer is preferable. . As the polybutadiene, both high cis polybutadiene having a high cis content and low cis polybutadiene having a low cis content can be used. Moreover, as a structure of a styrene-butadiene copolymer, both a random structure and a block structure can be used. These rubber-like polymers can be used alone or in combination of two or more. A saturated rubber obtained by hydrogenating a butadiene rubber can also be used.

  The rubber content contained in the rubber-modified styrenic resin is preferably 5 to 15% by mass, more preferably 6 to 14% by mass, from the viewpoint of the balance between mechanical strength and heat resistance of the molded article to be obtained. .

  The rubber particle diameter is 0.5 to 5.0 μm, preferably 0.7 to 4 μm, more preferably 1.0 to 3.0 μm, from the viewpoint of the balance between mechanical strength and appearance of the obtained molded body. . The rubber-modified styrenic resin is obtained by polymerizing a styrene monomer in a reactor equipped with a stirrer in the presence of a rubbery polymer. The rubber particle diameter is determined by the number of revolutions of the stirrer, the rubbery polymer used. The molecular weight can be adjusted.

  The method for producing the rubber-modified styrenic resin is not particularly limited, but bulk polymerization (or solution polymerization) in which a styrene monomer (and solvent) is polymerized in the presence of a rubbery polymer, or suspension during the reaction. It can be produced by bulk-suspension polymerization that shifts to turbid polymerization or emulsion graft polymerization in which a styrene monomer is polymerized in the presence of a rubber-like polymer latex. In bulk polymerization, a rubber-like polymer, a styrenic monomer, and a mixed solution to which an organic solvent, an organic peroxide, and / or a chain transfer agent are added as a complete mixing reactor or tank reactor. It can be produced by continuously supplying a plurality of tank reactors connected to a polymerization apparatus connected in series.

  The swelling index of the toluene-insoluble portion of the rubber-modified styrene resin is 8.0 to 14.0 from the viewpoint of excellent impact strength of the obtained molded article, and the toluene-insoluble portion relative to the rubber content in the toluene-insoluble portion. The mass ratio (toluene insoluble content / rubber content in the toluene insoluble content) is preferably 1.5 to 4.0. The swelling index is more preferably 9.0 to 13.0, still more preferably 9.5 to 12.5, and the ratio of the rubber content in the toluene insoluble content / toluene insoluble content is more preferably 2.0. -3.5, more preferably 2.5-3.5

  Regarding kneading of styrene methacrylic acid copolymer (A), polylactic acid (B), epoxidized oil (C), and styrene resin (D), dried styrene methacrylic acid copolymer (A) and poly After dry blending the lactic acid (B) with the epoxidized oil (C), the styrene resin (D) can be further blended and adjusted using an extruder.

  Further, as means for improving dispersibility and physical properties, those containing a compound (E) obtained by reacting a styrene-methacrylic acid copolymer (A), a polylactic acid (B) and an epoxidized oil (C) are more preferable.

  The following method (process) is mentioned as a method of obtaining the said compound (E).

Step (1): Dry polylactic acid (B) [non-terminal-modified (carboxyl group remaining)] and epoxidized oil (C) are dry-blended and polylactic acid (B) in a melt kneader. The carboxylic group of the epoxidized oil (C) is reacted with the carboxyl group.
Step (2): The dry styrene-methacrylic acid copolymer (A) is dry blended into the reaction mixture obtained in the step (1), and the epoxy remaining in the reaction mixture obtained in the step (1) The group is reacted with the carboxyl group of the styrene-methacrylic acid copolymer (A).

  As a condition for obtaining the compound (E), the molar ratio of the polylactic acid (B) and the epoxidized oil (C) can be expressed by the carboxyl group in the polylactic acid (B) / the epoxy group in the epoxidized oil (C). The ratio is preferably 1 / 1.1-1 / 20. This is because if the amount of carboxy group is large, the epoxy group to be reacted in the next step is insufficient, and if the amount of carboxy is small, it is difficult to obtain the compound (D) efficiently. In addition, each mole number was calculated | required using the molecular weight of each substance, the addition amount, the carboxy group number of polylactic acid, and the epoxy group number in 1 molecule of epoxidized oil.

  As a condition for suitably obtaining the compound (E), the theoretical residual epoxy group when the total amount of carboxy groups in the polylactic acid (B) reacts with the epoxy group in the epoxidized oil (C) in the step (1). It is preferable to use it so that the number of moles of the carboxy group in the styrene-methacrylic acid copolymer (A) is in the range of 0.1 to 150 times the number of moles. If it is this range, the reaction efficiency with the number-of-moles of the carboxyl group of a styrene methacrylic acid copolymer (A) and an epoxy group can be improved, intermolecular bridge | crosslinking can be suppressed and gelatinization can be prevented. In addition, about the mole number, about the styrene-methacrylic acid copolymer (A), it calculated | required from the addition amount, the methacrylic acid ratio in a styrene-methacrylic acid copolymer, and the molecular weight of a styrene-methacrylic acid copolymer. The number of moles of the theoretical residual epoxy group in step (1) is obtained by subtracting the total number of carboxy groups of polylactic acid from the total number of epoxy groups of the epoxidized oil added in step (1).

  When the compound (E), polylactic acid (B), and styrene resin (D) are added and melt-kneaded, the mass ratio of the polylactic acid (B) is 0. 0 with respect to the theoretical mass of the compound (E). It is preferably 5 to 5.0 times, and the styrene resin (D) is preferably in the range of 0.5 to 10.0 times the theoretical mass of the compound (E). If the ratio of the compound (E) with respect to the total mass is within this range, the dispersibility is improved and the mechanical properties of the resulting molded article are improved.

  There is no particular limitation on the mixing order of the resins. For example, after isolating the compound (E), the polylactic acid (B) and the styrene resin (D) are dry blended and further supplied to a melt kneader, After preparing a master batch in which the styrene resin (D), the isolated compound (E), the polylactic acid (B) and the isolated compound (E) were melt-kneaded, this master batch and the styrene resin (D) Or a method of melt-kneading polylactic acid (B). A method of adding the styrene resin (D) or the polylactic acid (B) in a state containing unreacted components without removing the compound (E) from the melt kneader may be used.

  In addition, if necessary, a method of melt-kneading other additives at the same time, or preparing a master batch in which styrene-methacrylic acid copolymer (A) or polylactic acid (B) and other additives are previously melt-kneaded Alternatively, a method of melt-kneading the master batch, the styrene resin (D) and the polylactic acid (B) may be used.

  Moreover, it is preferable that the temperature at the time of melt-kneading each component is in the range of 180 ° C. to 260 ° C. From the viewpoint that the compound (E) can be efficiently generated in the process, and deterioration of the polylactic acid (B) due to heat. From the viewpoint of prevention and from the viewpoint of kneadability of the polylactic acid (B) and the styrene resin (D), the temperature at which each component is melt-kneaded is more preferably in the range of 190 ° C to 240 ° C.

  In the present invention, the styrene-methacrylic acid copolymer (A), polylactic acid (B), epoxidized oil (C), styrenic resin (D), and compound (E) are used in the above blending ratio. However, if necessary, other resins and various additives may be used in combination to form a styrene resin composition.

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

  The obtained styrene-based resin composition has particularly improved compatibility between the styrene-based resin (D) and the polylactic acid (B), has excellent moldability, and the mechanical properties of the resulting molded body are good. . Therefore, it is possible to use molding methods such as injection molding, sheet extrusion molding, foam molding, vacuum molding, and blow molding. Moreover, it can use for various uses. Specifically, it can be suitably used for parts for electric / electronic devices, automobile parts, packaging applications, daily commodities, and the like.

  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.

  The raw materials, intermediate raw materials, and physical properties of the obtained styrene resin composition were measured and evaluated by the following methods.

(1) Molecular weight measurement [styrene methacrylate copolymer, polylactic acid, styrene resin (polystyrene (GPPS) and multi-branched polystyrene)]
Using a high-speed GPC HLC-8220 (manufactured by Tosoh Corporation) and a column (TSK-GELGMHXL × 2), a solution prepared by dissolving 5 mg of a sample in 10 g of THF was injected into the apparatus (200 μL), and a flow rate: 1 ml / min (THF ), Thermostat temperature: 40 ° C., measured with an RI detector.

(2) Dispersion state (compatibility) observation The sample was cut out and the cross section was produced with an ultramicrotome, and confirmed with an optical microscope. Good dispersibility was indicated by ◯, substantially good dispersibility by Δ, and poor dispersibility by x.

(3) Bending test A measurement sample (shape: width 10 mm, thickness: 2.0 mm) was measured with a bending tester (Instron). (Conditions: Span ratio: 40 mm, speed: 2.0 mm / min) Less than 75 MPa was evaluated as x, 75 MPa or more and less than 80 MPa was evaluated as Δ, and 80 MPa or more was evaluated as ◯.

(4) Oil resistance Using a hot plate press (230 ° C.), a styrenic resin composition is used to produce a sheet having a thickness of 100 μm, cut into a 100 × 20 mm strip, wound around a paper tube having a diameter of 90 mm, and edible oil ( White F-2 (manufactured by Fuji Seiki Co., Ltd.) was applied and allowed to stand in a thermostatic device at 60 ° C., and the crack condition after 1 hour was confirmed. The case with cracks was rated as x, the case with some cracks as Δ, and the case without change as ○.

  As the styrene-methacrylic acid copolymer (A), (A-1): styrene / methacrylic acid = 90/10 (mass%), weight average molecular weight (Mw): 320,000, fluidity: 2.5 g / 10 min. . (230 ° C., 37.3 N) and (A-2): styrene / methacrylic acid = 98/2 (mass%), weight average molecular weight (Mw): 300,000, fluidity: 4.5 g / 10 min. (230 ° C., 37.3 N) was used.

  As polylactic acid (B), fluidity 10 g / 10 min (190 ° C., 21.2 N), D-form: 1.4 mol%, weight average molecular weight: 180,000, terminal unmodified (carboxy group remaining) raw material is used. did.

  As the epoxidized oil (C), “Eposizer W-100-EL” (molecular weight: 933) manufactured by DIC Corporation as epoxidized soybean oil, and “Eposizer W-109” (molecular weight: manufactured by DIC Corporation) as epoxidized linseed oil. 975) was used.

  As the styrene resin (D), (D-1): polystyrene (GPPS) weight average molecular weight (Mw): 320,000, fluidity: 1.5 g / 10 min. (200 ° C., 49N), (D-2): Multi-branched polystyrene [Product name: High Branch HP-500M (manufactured by DIC Corporation)] Weight average molecular weight (Mw): 270,000, Fluidity: 2.8 g / 10 min. (200 ° C., 49N) and (D-3): Rubber-modified polystyrene (HIPS): Fluidity: 2.0 g / 10 min. (200 ° C., 49 N), a rubber component content of 7% in the resin was used.

A method for synthesizing rubber-modified polystyrene (HIPS) is as follows.
Add 90 parts of styrene monomer, 10 parts of toluene, 6 parts of butadiene rubber, 300 ppm of t-butyl peroxybenzoate (monomer ratio), and in a stirred reaction vessel, 1.5 hours at 130 ° C., 140 ° C. to 180 ° C. The mixture is reacted for 3.5 hours, and unreacted monomers and toluene are heated at 230 ° C. and the degree of vacuum is 70-30 Torr. And purified by purification.

Reference Example 1 (Synthesis of Compound E-1)
Step (1): Laboplast mill [Mixer (R-60) (Toyo Seiki), all of which are the same for Laboplast Mill), dried polylactic acid: 50 g, Eposizer W-100-EL: 0.1 g was added. (Mole ratio of carboxyl group / epoxy group = 1 / 1.15), and melt-kneaded at 210 ° C for 30 minutes.

  Step (2): The reaction mixture obtained in Step (1): 0.212 g and styrene-methacrylic acid copolymer (A-1): 50 g were added to Laboplastmill (theoretical residual epoxy group in Step (1)). Mole number / Carboxy group mole number of styrene / methacrylic acid copolymer = 1 / 85.7), 210 ° C., melt-kneaded for 30 minutes to obtain a mixture containing compound E-1.

Reference Example 2 (Synthesis of Compound E-2)
Step (1): Polylactic acid dried in a lab plast mill: 50 g, Eposizer W-100-EL: 0.3 g was added (carboxyl group / epoxy group molar ratio = 1 / 3.46), 210 ° C., Melted and kneaded for 30 minutes.

  Step (2): The reaction mixture obtained in Step (1): 0.212 g and styrene-methacrylic acid copolymer (A-1): 50 g were added to Laboplastmill (theoretical residual epoxy group in Step (1)). Mole number / Carboxy group mole number of styrene / methacrylic acid copolymer = 1 / 5.4), 210 ° C., melt-kneaded for 30 minutes to obtain a mixture containing compound E-2.

Reference Example 3 (Synthesis of Compound E-3)
Step (1): Laboplast mill-dried polylactic acid: 50 g, Eposizer W-109: 0.15 g was added (carboxyl group / epoxy group molar ratio = 1 / 3.32), and melted at 210 ° C. for 30 minutes. Kneaded.

  Step (2): The reaction mixture obtained in Step (1): 0.53 g and styrene methacrylic acid copolymer (A-1): 50 g were added to Laboplastmill (theoretical residual epoxy group in Step (1)). Mole number / Carboxy group mole number of styrene / methacrylic acid copolymer = 1 / 2.3), 210 ° C., melt-kneaded for 30 minutes to obtain a mixture containing compound E-3.

Reference Example 4 (Synthesis of Compound E-4)
Step (1): Polylactic acid dried to Laboplast Mill: 50 g, Eposizer W-109: 0.45 g was added (carboxyl group / epoxy group molar ratio = 1 / 9.97), 210 ° C., 30 minutes Melted and kneaded.

  Step (2): The reaction mixture obtained in Step (1): 0.53 g and styrene methacrylic acid copolymer (A-1): 50 g were added to Laboplastmill (theoretical residual epoxy group in Step (1)). The number of moles / the number of carboxy groups in the styrene-methacrylic acid copolymer = 1 / 0.6) was melt-kneaded at 210 ° C. for 30 minutes to obtain a mixture containing the compound E-4.

Reference Example 5 (Synthesis of Compound E-5)
Step (1): Laboplast mill [Mixer (R-60) (Toyo Seiki), all of which are the same for Laboplast Mill), dried polylactic acid: 50 g, Eposizer W-100-EL: 0.1 g was added. (Mole ratio of carboxyl group / epoxy group = 1 / 1.15), and melt-kneaded at 210 ° C for 30 minutes.

  Step (2): The reaction mixture obtained in Step (1): 0.212 g and styrene-methacrylic acid copolymer (A-2): 50 g were added to Laboplastmill (theoretical residual epoxy group in Step (1)) Mole number / Carboxy group mole number of styrene / methacrylic acid copolymer = 1 / 17.1), 210 ° C., melt-kneaded for 30 minutes to obtain a mixture containing compound E-5.

Example 1
Styrene methacrylic acid copolymer (A-1): 15 g, polylactic acid (B): 15 g, epoxidized soybean oil: 0.1 g, styrene-based resin (D-1): 15 g are dry blended, and Laboplast mill is used. And kneaded at 230 ° C. for 15 minutes to obtain a styrene resin composition.

Example 2
Polylactic acid (B): 15 g, Styrenic resin (D-1): 15 g, 15 g of a mixture containing the compound (E-1) obtained in Reference Example 1 was dry blended and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Example 3
Polylactic acid (B): 6.5 g, Styrenic resin (D-1): 32.5 g, a mixture containing compound (E-1) obtained in Reference Example 1: 6.5 g was dry blended, and Laboplast The styrene resin composition was obtained by kneading at 230 ° C. for 10 minutes using a mill.

Example 4
15 g of polylactic acid (B), 15 g of styrene-based resin (D-1), and 15 g of a mixture containing the compound (E-2) obtained in Reference Example 1 were dry blended and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Example 5
Polylactic acid (B): 6.5 g, Styrenic resin (D-1): 32.5 g, a mixture containing the compound (E-2) obtained in Reference Example 1: 6.5 g was dry blended, and Laboplast The styrene resin composition was obtained by kneading at 230 ° C. for 10 minutes using a mill.

Example 6
Polylactic acid (B): 15 g, Styrenic resin (D-1): 15 g, 15 g of a mixture containing the compound (E-3) obtained in Reference Example 1 was dry blended, and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Example 7
Polylactic acid (B): 6.5 g, Styrenic resin (D-1): 32.5 g, a mixture containing compound (E-3) obtained in Reference Example 1: 6.5 g was dry blended, and Laboplast The styrene resin composition was obtained by kneading at 230 ° C. for 10 minutes using a mill.

Example 8
15 g of polylactic acid (B), 15 g of styrene resin (D-1), and 15 g of a mixture containing the compound (E-4) obtained in Reference Example 1 were dry-blended and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Example 9
Polylactic acid (B): 6.5 g, Styrenic resin (D-1): 32.5 g, a mixture containing compound (E-4) obtained in Reference Example 1: 6.5 g was dry blended, and Laboplast The styrene resin composition was obtained by kneading at 230 ° C. for 10 minutes using a mill.

Example 10
15 g of polylactic acid (B), 15 g of styrene resin (D-1), and 15 g of a mixture containing the compound (E-5) obtained in Reference Example 1 were dry-blended and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Example 11
Polylactic acid (B): 6.5 g, Styrenic resin (D-1): 32.5 g, a mixture containing compound (E-5) obtained in Reference Example 1: 6.5 g was dry blended, and Laboplast The styrene resin composition was obtained by kneading at 230 ° C. for 10 minutes using a mill.

Example 12
Polylactic acid (B): 15 g, Styrenic resin (D-2): 15 g, 15 g of a mixture containing the compound (E-5) obtained in Reference Example 1 was dry blended and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Example 13
15 g of polylactic acid (B), 15 g of styrene resin (D-3), and 15 g of a mixture containing the compound (E-5) obtained in Reference Example 1 were dry-blended and used at 230 ° C. for 10 minutes. The styrene resin composition was obtained by kneading.

Comparative Example 1
Styrene methacrylic acid copolymer (A-1): 15 g, polylactic acid (B): 15 g, and styrene resin (D-1): 15 g are dry blended and kneaded at 230 ° C. for 15 minutes using a lab plast mill. Thus, a styrene resin composition was obtained.

Comparative Example 2
25 g of polylactic acid (B) and 25 g of styrene resin (D-1) were dry blended and kneaded at 230 ° C. for 10 minutes using a lab plast mill to obtain a styrene resin composition.

Comparative Example 3
25 g of polylactic acid (B) and 25 g of styrene resin (D-2) were dry blended and kneaded at 230 ° C. for 10 minutes using a lab plast mill to obtain a styrene resin composition.

Comparative Example 4
25 g of polylactic acid (B) and 25 g of styrene resin (D-3) were dry blended and kneaded at 230 ° C. for 10 minutes using a lab plast mill to obtain a styrene resin composition.

Comparative Example 5
Evaluation similar to the said resin composition was performed about styrene-type resin (D-1).

Comparative Example 6
Evaluation similar to the said resin composition was performed about styrene-type resin (D-2).

Comparative Example 7
Evaluation similar to the said resin composition was performed about styrene-type resin (D-3).

  The evaluation results are shown in Tables 1-3.

Claims (10)

A styrene-based resin comprising a styrene-methacrylic acid copolymer (A), a polylactic acid (B), an epoxidized oil (C), and a styrene-based resin (D) other than the styrene-methacrylic acid copolymer. Resin composition. The styrenic resin composition according to claim 1, wherein the epoxidized oil (C) is epoxidized soybean oil or epoxidized linseed oil. The styrene-based resin composition according to claim 1 or 2, comprising a compound (E) obtained by reacting a styrene-methacrylic acid copolymer (A), a polylactic acid (B), and an epoxidized oil (C). The compound (E) reacts with the carboxy group in the polylactic acid (B) and a part of the epoxy group in the epoxidized oil (C), and then reacts with the styrene-methacrylic acid copolymer (A). The styrenic resin composition according to claim 3, which is a block copolymer obtained by reacting the remaining epoxy group and the carboxy group in the styrene methacrylic acid copolymer (A) in addition to the system. The styrene resin composition according to any one of claims 1 to 4, wherein the styrene resin (D) other than the styrene methacrylic acid copolymer is polystyrene, rubber-modified polystyrene, or hyperbranched polystyrene. (1) Melting and kneading polylactic acid (B) and epoxidized oil (C),
(2) After the step (1), a step of adding a styrene-methacrylic acid copolymer (A) and further melt-kneading,
(3) A styrenic resin comprising a step of adding and melt-kneading a styrene resin (D) other than the polylactic acid (B) and the styrene-methacrylic acid copolymer after the step (2). A method for producing the composition. The molar ratio in which the proportion of polylactic acid (B) and epoxidized oil (C) used in step (1) is represented by the carboxy group in polylactic acid (B) / the epoxy group in epoxidized oil (C). The method for producing a styrene-based resin composition according to claim 6, wherein the range is 1 / 1.1-1 / 20. The use ratio of the styrene-methacrylic acid copolymer (A) in the step (2) is that in the step (1), the total amount of carboxy groups in the polylactic acid (B) reacts with the epoxy groups in the epoxidized oil (C). The styrene methacrylic acid copolymer (A) is used so that the number of moles of carboxy groups in the styrene-methacrylic acid copolymer (A) is in the range of 0.1 to 150 times the number of moles of theoretical residual epoxy groups. Or the manufacturing method of the styrene-type resin composition of 7. The use ratio of polylactic acid (B) in the step (3) is in a range of 0.5 to 5.0 times the theoretical mass after the step (2). The manufacturing method of the styrene resin composition of description. The use ratio of the styrene resin (D) other than the styrene methacrylic acid copolymer in the step (3) is in the range of 0.5 to 10.0 times the theoretical mass after the step (2). The manufacturing method of the styrene-type resin composition in any one of Claims 6-9.