JPWO2020137843A1 - Resin composition and molded product - Google Patents

Abstract

Provided is a resin composition in which the die does not adhere to the die in the extrusion manufacturing process. We have found that a resin composition that does not generate eyebrows can be obtained by blending a specific acrylic resin with a resin composition containing a styrene resin and a polyester resin, and have reached the present invention. That is, the present invention is characterized in that the (C) polyester resin is contained in an amount of 0.1 part by mass or more and 2 parts by mass or less with respect to a total of 100 parts by mass of the (A) styrene resin and the (B) polyester resin. It is a resin composition.

Description

The present invention relates to a resin composition in which nails do not adhere to the die in the extrusion manufacturing process and a molded product thereof.

Styrene-based resins are used in a wide range of fields, including personal computers, printers, OA equipment such as copiers, and home appliances such as TVs and audios, taking advantage of their characteristics.

On the other hand, polyester-based resins are widely used in various industrial applications such as films, sheets, tableware, and packaging containers because they have excellent mechanical properties.

In recent years, there has been a demand for reduction of carbon dioxide due to the problem of global warming, and polylactic acid is attracting attention as one of the "carbon-neutral" polyester-based resins that apparently do not emit carbon dioxide. However, since polylactic acid is inferior in practicality as a durable consumer goods, polymer alloys with styrene-based resins and the like have been studied in recent years.

A polymer alloy of a styrene resin and polylactic acid is usually produced by extrusion molding, but at that time, a resin decomposition product, an undispersed additive, or the like is generated at the die outlet portion of the extruder. The generated mayani exists in a state of being accompanied by the strand and adhering to the pellet after pelletizing, but this not only deteriorates the appearance of the pellet itself, but also causes coloring spots on the surface of the molded body after molding such as injection molding. It is a problem because it remains as a poor appearance.

On the other hand, as a method for suppressing mayani, a method of adding a higher fatty acid amide or a higher fatty acid alkali metal salt to a styrene resin composition containing polyphenylene ether is exemplified (Patent Document 1). However, this method does not have a sufficient effect of suppressing eyebrows in a styrene-based resin composition containing a polyester-based resin such as polylactic acid.

Japanese Unexamined Patent Publication No. 2012-41502

An object of the present invention is to provide a resin composition in which the die does not adhere to the die in the extrusion manufacturing process.

As a result of diligent research to solve the above-mentioned problems, the present inventor can suppress the generation of eyebrows by blending a specific acrylic resin with a resin composition containing a styrene resin and a polyester resin. And arrived at the present invention.

That is, the present invention is as follows.
1. 1. A resin composition containing (A) a styrene resin and (B) a polyester resin, 0.1 part by mass with respect to 100 parts by mass of the total of (A) styrene resin and (B) polyester resin. A resin composition comprising (C) an acrylic resin of 2 parts by mass or less.
2. 2. (B) The resin composition according to 1 above, wherein the polyester-based resin is polylactic acid.
3. 3. In a total of 100 parts by mass of the (A) styrene resin and the (B) polyester resin, the (A) styrene resin is 55 parts by mass or more and 90 parts by mass or less, and the (B) polyester resin is 10 parts by mass or more and 45 parts by mass. The resin composition according to 1 or 2 above, which is characterized by having a mass of parts or less.
4. The acrylic resin (C) is a monomer having an alkyl group having a weight average molecular weight Mw of 50,000 or more and 400,000 or less and a carbon number of 1 or more and 20 or less, and a single amount copolymerizable with them. The resin composition according to any one of 1 to 3 above, which is a copolymer composed of a body.
5. Further, the above-mentioned characterized by containing 0.1 part by mass or more and 1.5 parts by mass or less of (D) polyolefin-based wax with respect to 100 parts by mass in total of (A) styrene-based resin and (B) polyester-based resin. The resin composition according to any one of 1 to 4.
6. A molded product comprising the resin composition according to any one of 1 to 5 above.

In the resin composition of the present invention, the meshi, which causes poor molding appearance in the extrusion manufacturing process, does not adhere to the die. Therefore, the molded body obtained by molding the resin composition of the present invention has an excellent appearance and can be effectively used in applications such as OA equipment, home appliances, tableware, and packaging containers.

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

First, (A) a styrene-based resin will be described. The (A) styrene-based resin used in the present invention is obtained by polymerizing an aromatic vinyl compound-based monomer. As the aromatic vinyl compound-based monomer, known ones such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, and 2,4-dimethylstyrene can be used, but preferably. It is styrene. These monomers may be used alone or in combination. In addition, monomers such as acrylonitrile, (meth) acrylic acid, (meth) acrylic acid ester, and maleic anhydride, which can be copolymerized with these monomers, do not impair the performance of the (A) styrene resin. If there is, it may be added and polymerized.

Further, the (A) styrene-based resin may be rubber-modified by adding a conjugated diene-based rubber-like polymer, if necessary. Conjugated diene rubber-like polymers used for rubber modification include polybutadiene, styrene-butadiene random or block copolymer, polyisoprene, polychloroprene, styrene-isoprene random, block or graft copolymer, and ethylene-propylene rubber. , Ethylene-propylene-diene rubber and the like, but polybutadiene, styrene-butadiene random, block or graft copolymers are particularly preferred. Further, these may be partially hydrogenated.

Examples of such (A) styrene-based resin include polystyrene (GPPS), rubber-modified polystyrene (HIPS), ABS resin (acrylonitrile-butadiene-styrene copolymer), AS resin (acrylonitrile-styrene copolymer), and MS. Examples thereof include a resin (methyl methacrylate-styrene copolymer), an AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), and an AES resin (acrylonitrile-ethylene propylene-styrene copolymer). Among these, HIPS is particularly preferable because it can increase the impact resistance of the resin composition.

The molecular weight of the matrix portion of HIPS is not particularly limited, but the reduction viscosity (ηsp / C) is preferably 0.5 or more and 1.0 or less. When it is 0.5 or more, the molten strand of the resin is less likely to be broken, which is advantageous for stable production, which is preferable. Further, when it is 1.0 or less, the fluidity of the molten resin can be ensured, which is preferable.

The content of the rubber-like polymer in HIPS is not particularly limited, but is preferably 3% by mass or more and 10% by mass or less. It is preferable that the content of the rubber-like polymer is in this range because the impact resistance and the rigidity of the molded product are well-balanced.

Next, (B) the polyester resin will be described. The (B) polyester-based resin used in the present invention is a general term for polymers having an ester bond obtained by polymerizing a polyvalent carboxylic acid and a polyalcohol.

(B) The polyester-based resin can be obtained, for example, by polymerization of a dicarboxylic acid and a diol. Such polyester-based resins include, for example, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, and further. Examples thereof include polyhexamethylene terephthalate and polyhexamethylene naphthalate, but the present invention is not limited thereto.

Examples of the dicarboxylic acid component include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 4,4'-diphenyldicarboxylic acid. , 4,4'-Diphenyl ether dicarboxylic acid, 4,4'-diphenylsulfone dicarboxylic acid and other aromatic dicarboxylic acids can be mentioned. In addition, aliphatic dicarboxylic acids such as adipic acid, suberic acid, sebacic acid, dimer acid, dodecandionic acid, cyclohexanedicarboxylic acid and their ester derivatives can be mentioned. Only one kind of these carboxylic acid components may be used, two or more kinds thereof may be used in combination, and an oxyacid such as hydroxybenzoic acid may be partially copolymerized.

Examples of the diol component include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, and 1,5-pentane. Diol, 1,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis (4) -Hydroxyethoxyphenyl) Propane, isosorbate, spiroglycol and the like can be mentioned.

On the other hand, the (B) polyester-based resin can also be obtained by polymerizing a monomer having both a carboxylic acid and an alcohol in a single compound, and examples of such a polyester-based resin include polylactic acid.

Among the polyester resins (B) mentioned above, polylactic acid is preferable from the viewpoint of carbon neutrality.

As polylactic acid, poly (L-lactic acid) is used. From the viewpoint of reducing carbon dioxide emissions, plant-derived raw materials are preferable.

In the case of poly (L-lactic acid), the crystallization rate differs depending on the ratio of the D-lactic acid component contained as the monomer component. Considering the heat resistance and moldability of the resin composition of the present invention, poly (L-lactic acid) composed only of L-lactic acid is preferable, and when a D-lactic acid component is contained, the ratio thereof is 5.0. It is preferably mol% or less. Particularly preferably, it is 1.5 mol% or less.

The molecular weight of polylactic acid preferably has a weight average molecular weight (Mw) of 50,000 or more and 400,000 or less, and is particularly preferably in the range of 100,000 or more and 300,000 or less.

The ratio of (A) styrene resin to (B) polyester resin is not particularly limited, but when the total of (A) styrene resin and (B) polyester resin is 100 parts by mass, (A) ) The styrene resin is preferably 55 parts by mass or more and 90 parts by mass or less, and (B) the polyester resin is preferably 10 parts by mass or more and 45 parts by mass or less. (B) It is preferable that the ratio of the polyester resin is in this range because the effect of reducing the environmental load and the price competitiveness can be achieved at the same time.

Next, (C) an acrylic resin will be described. In the present invention, the (C) acrylic resin refers to a polymer obtained by polymerizing an acrylic monomer or the like. The (C) acrylic resin has excellent compatibility with the (B) polyester resin, and in order to reduce the friction between the resin composition and the die outlet, etc., the resin composition containing (B) the polyester resin. However, by containing (C) an acrylic resin, an effect of preventing eyebrows can be obtained.

The content of the acrylic resin (C) is 0.1 part by mass or more and 2 parts by mass or less with respect to 100 parts by mass in total of (A) styrene resin and (B) polyester resin from the viewpoint of the effect of suppressing eyebrows. Is. (C) When the content of the acrylic resin exceeds 2 parts by mass, the acrylic resin bleeds out on the strand surface during extrusion production, and the acrylic resin itself transferred and adhered to the die outlet portion becomes a source of Mayani, which is unsuitable. Is.

(C) The type of the acrylic monomer constituting the acrylic resin is not particularly limited as long as the effect of the present invention is not impaired, and for example, methyl acrylate, ethyl acrylate, isopropyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like. Acrylate monomers such as benzyl acrylate, cyclohexyl acrylate, phenyl acrylate, and chloroethyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, and phenyl. A homopolymer of a methacrylate monomer such as a methacrylate or a chloroethyl methacrylate, or a copolymer obtained by copolymerizing two or more of these monomers can be used.

(C) The acrylic resin may be polymerized by adding a vinyl monomer copolymerizable with these, in addition to these acrylic monomers, as long as the effect of the present invention is not impaired. For example, α-olefin. , Vinyl aromatics, unsaturated nitriles, unsaturated carboxylic acids or esters thereof, polyunsaturated compounds such as ethylene glycol di (meth) acrylate may be added and polymerized.

(C) The acrylic resin is preferably a high molecular weight material. Specifically, it is preferable that the polystyrene-equivalent weight average molecular weight Mw measured by GPC is 50,000 or more and 400,000 or less. More preferably, it is 100,000 or more and 300,000 or less.

(C) The acrylic resin having higher performance as a lubricant is preferable from the viewpoint of the effect of reducing eyelids. That is, it is preferable that the copolymer is composed of an acrylic monomer having a chemical structure capable of further reducing friction with the die outlet and the like, and a monomer copolymerizable with the acrylic monomer.

The acrylic monomer having a chemical structure capable of reducing friction is more specifically a monomer having an alkyl group having 1 or more and 20 or less carbon atoms, and alkyl methacrylate or alkyl acrylate is preferable. Examples thereof include methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate and the like. It is preferable to use at least one of these.

Examples of the (C) acrylic resin satisfying such conditions include "Metabrene (registered trademark) L-1000" and "Metabrene (registered trademark) P-700" manufactured by Mitsubishi Chemical Corporation.

Next, (D) the polyolefin wax will be described. The resin composition of the present invention may contain (D) a polyolefin-based wax for the purpose of further enhancing the effect of (C) the acrylic resin on suppressing the generation of shavings. Examples of the polyolefin wax that can be used in the present invention include aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and paraffin wax.

The content of the polyolefin-based wax (D) is preferably 0.1 parts by mass or more and 1.5 parts by mass or less with respect to 100 parts by mass in total of the (A) styrene-based resin and (B) polyester-based resin. .. Within this range, (C) the effect of enhancing the suppression of shavings by the combined use with the acrylic resin can be sufficiently exhibited, and the amount of gas generated during processing can be suppressed.

Other additives such as plasticizers, spreading agents, solvents, UV absorbers, antioxidants, antioxidants, light stabilizers, stabilizers, antistatic agents, colorants, as long as the object of the present invention is not impaired. Dyeing pigments, fillers, color inhibitors, reinforcing agents, compatibilizers, crystallization accelerators, flame retardants, flame retardant aids, etc. can be added.

In particular, MBS as a reinforcing agent, talc as a crystallization accelerator, and liquid paraffin as a spreading agent can be preferably added. MBS is a copolymer of methyl methacrylate, butadiene, and styrene, and is well-suited to any of (B) polyester-based resin, (A) styrene-based resin, and (C) acrylic-based resin, and the resin composition of the present invention. It is preferable because the impact resistance of the above can be efficiently reinforced. Talc is preferable because it can promote the crystallization of the polyester resin (B) in the present invention and can improve the mechanical strength of the resin composition. Liquid paraffin is a saturated hydrocarbon purified by removing impurities such as aromatic hydrocarbons and sulfur compounds contained in the lubricating oil fraction of petroleum with anhydrous sulfuric acid or fuming sulfuric acid, and is used when mixing the resin composition of the present invention. In addition, since it is possible to suppress classification between resins having different specific gravities, it is possible to suppress quality variation of the resin composition during extrusion production, which is preferable.

The method of adding the above-mentioned additive is not particularly limited, and it may be added by a known method. For example, a method of adding a raw material during the production of (A) styrene resin or (B) polyester resin, a polymerization step, a finishing step, or a step of mixing a resin composition using an extruder or a molding machine. The method of adding in can be applied.

Next, a method for producing the resin composition of the present invention will be described.
The method for producing the resin composition of the present invention is not particularly limited, and known mixing techniques can be applied. For example, a uniform resin composition is produced by mixing various raw materials in advance using a mixing device such as a mixer-type mixer, a V-type blender, and a tumbler-type mixer, and melting and kneading the mixture. Can be done. The melt-kneading device is also not particularly limited, and examples thereof include a Banbury type mixer, a kneader, a roll, a single-screw extruder, a special single-screw extruder, and a twin-screw extruder. Further, there is also a method of separately adding another additive from the middle of a melt-kneading device such as an extruder.

The molding method for obtaining a molded product from the resin composition of the present invention is not particularly limited, and is calender molding, hollow molding, extrusion foam molding, deformed extrusion molding, laminate molding, inflation molding, T-die film molding, sheet molding, vacuum molding. , A known molding method such as an extrusion molding method such as pressure molding and an injection molding method such as injection molding, RIM molding, and injection foam molding can be preferably used, but injection molding or sheet molding is preferable.

Hereinafter, the present invention will be described in detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The materials used in the examples and comparative examples are as follows.
〔material〕
(A) Styrene-based resin Rubber-modified impact-resistant polystyrene resin (rubber-like polymer is polybutadiene rubber, reduction viscosity of matrix portion is 0.70 dl / g, rubber-like polymer content is 9.2% by mass)
(B) Polyester-based resin Polylactic acid: "REVODE190" manufactured by Zhejiang Hisun Biomaterials Co., Ltd. (D-lactic acid component ratio 0.5 mol%, weight average molecular weight (Mw) 200,000)
PET: Eastman "PET-G GN001"
(C) Acrylic resin "Metabrene L-1000" manufactured by Mitsubishi Chemical Corporation (weight average molecular weight (Mw) 250,000)
"Metabrene P-700" manufactured by Mitsubishi Chemical Corporation (weight average molecular weight (Mw) 450,000)
(D) Polyolefin wax "viscowax115" manufactured by Inospec Inc.
(E) Zinc stearate "Zinc stearate GP" manufactured by NOF CORPORATION

[Measurement method of reduced viscosity]
(A) A mixed solvent of 17.5 ml of methyl ethyl ketone and 17.5 ml of acetone is added to 1 g of a styrene resin, and the mixture is dissolved by shaking at a temperature of 25 ° C. for 2 hours, then the insoluble matter is precipitated by centrifugation, and the supernatant liquid is decanted. It was taken out, 250 ml of methanol was added to precipitate the resin component, and the insoluble component was filtered and dried. The resin component obtained by the same operation was dissolved in toluene to prepare a sample solution having a polymer concentration of 0.4% (mass / volume). This sample solution and pure toluene were measured at a constant temperature of 30 ° C. with a Ubbelohde viscometer for the number of seconds of solution flow, and calculated by the following formula.
ηsp / C = (t1 / t0-1) / C
t0: Number of seconds of pure toluene flowing down t1: Number of seconds of sample solution flowing down C: Polymer concentration

[Method for measuring the content of rubber-like polymer]
Dissolve a styrene resin in chloroform, add a certain amount of iodine monochloride / glacial acetic acid solution, leave it in the dark for about 30 minutes, add 15% by mass of potassium iodide solution and 50 ml of pure water, and add excess iodine monochloride. Was titrated with a 0.1 N sodium thiosulfate solution and calculated from the amount of iodine monochloride added.

〔Evaluation method〕
After 50 kg of the resin composition was extruded by a twin-screw extruder, the determination was made by visual observation of the die outlet portion. Of the criteria below, A and B were accepted, and C was rejected.
A: No meyani was observed.
B: A small amount of eyebrows was observed.
C: Obviously a problematic amount of eyebrows was observed.

(Examples 1 to 11 and Comparative Examples 1 to 4)
Tables 1 and 2 show (A) styrene resin, (B) polyester resin, (C) acrylic resin, (D) polyolefin wax, and (E) zinc stearate listed in the above [Material]. Premix with a Henshell mixer (“FM20B” manufactured by Mitsui Miike Kako Co., Ltd.) with the indicated compounding amount (part by mass), supply to a twin-screw extruder (“TEM26SS” manufactured by Toshiba Machine Co., Ltd.) to form strands, and cool with water. Was led to a pelletizer and pelletized. In the above step, the state of occurrence of shavings was observed by the above-mentioned evaluation method. The results are shown in Tables 1 and 2.

From the examples in Table 1, it can be seen that the resin composition of the present invention suppresses the generation of eyebrows during production. On the other hand, from the comparative examples in Table 2, it can be seen that the resin composition that does not satisfy the provisions of the present invention produces a large amount of eyebrows.

Claims (6)

A resin composition containing (A) a styrene resin and (B) a polyester resin, 0.1 part by mass with respect to 100 parts by mass of the total of (A) styrene resin and (B) polyester resin. A resin composition comprising (C) an acrylic resin of 2 parts by mass or less. The resin composition according to claim 1, wherein the polyester-based resin (B) is polylactic acid. In a total of 100 parts by mass of the (A) styrene resin and the (B) polyester resin, the (A) styrene resin is 55 parts by mass or more and 90 parts by mass or less, and the (B) polyester resin is 10 parts by mass and 45 parts by mass. The resin composition according to claim 1 or 2, wherein the resin composition is as follows. The acrylic resin (C) is a monomer having an alkyl group having a weight average molecular weight Mw of 50,000 or more and 400,000 or less and a carbon number of 1 or more and 20 or less, and a single amount copolymerizable with them. The resin composition according to any one of claims 1 to 3, wherein the resin composition is a copolymer composed of a body. Further, the claim is characterized in that (D) the polyolefin-based wax is contained in an amount of 0.1 part by mass or more and 1.5 parts by mass or less with respect to a total of 100 parts by mass of the (A) styrene resin and the (B) polyester resin. Item 6. The resin composition according to any one of Items 1 to 4. A molded product comprising the resin composition according to any one of claims 1 to 5.