JP2022068044A - Resin composition, masterbatch and sheet - Google Patents

Abstract

To provide a resin composition that achieves both of high impact resistance and high rigidity.SOLUTION: A resin composition contains a styrene-(meth)acrylic acid resin, polypropylene resin, polystyrenic resin, and hydrogenated styrene-butadiene resin.SELECTED DRAWING: None

Description

The present invention relates to a resin composition, a masterbatch for the resin composition, and a sheet.

In recent years, there has been an increasing tendency for polymer materials to have conflicting properties such as heat resistance and moldability. Therefore, polymer alloys that blend multiple types of resins are attracting attention for the purpose of taking advantage of their strengths and improving their weaknesses. For example, polystyrene-based resins are used in a wide range of fields such as automobile parts, electrical parts, lighting equipment, and displays because they are excellent in transparency, gloss, and moldability, but they have low impact strength and heat resistance. Uses are limited. Various polymer alloys in which other resins such as polyphenylene ether-based resin (PPE), polyolefin-based resin, and styrene-acrylic acid copolymer resin (SMAA) are blended with such polystyrene-based resin have been studied. ..

For example, in Patent Document 1, a polypropylene resin film and a polyphenylene ether are used for the purpose of using scraps such as loss (hereinafter referred to as trimming loss) caused by cutting the end portion of a product in a post-process as a recycling raw material. A technique for blending a trimming loss containing a heat-resistant polystyrene-based resin contained therein, a virgin material (polyphenylene ether and a polystyrene resin), and a compatibilizer is disclosed. Further, Patent Document 2 discloses a technique of blending a styrene-acrylic acid copolymer resin (SMAA) with a polystyrene-based resin in a predetermined ratio for the purpose of ensuring heat resistance.

Japanese Unexamined Patent Publication No. 2012-40868 Japanese Unexamined Patent Publication No. 2018-44086

Since the technique of Patent Document 1 uses polyphenylene ether, which is highly compatible with polystyrene-based resin, as a raw material, it is easy to secure compatibility between the resins, but the impact strength, which is a disadvantage of polystyrene-based resin, is high. No improvement has been considered. Furthermore, since the technique of Patent Document 1 focuses on the compatibility between the polyphenylene ether, the compatibilizer, and the polystyrene-based resin, its use is limited to recycled raw materials containing the polyphenylene ether.

Further, the technique of Patent Document 2 is blended with a styrene-acrylic acid copolymer resin (SMAA) in order to improve the heat resistance which is a disadvantage of the polystyrene-based resin, but both the polystyrene-based resin and the styrene-acrylic acid are used. Since the compatibility with the polymer resin (SMAA) is low, a new problem arises in which the two are phase-separated and the impact strength is lowered.
Therefore, the present invention solves the above-mentioned problems, and an object of the present invention is to provide a resin composition having both excellent impact resistance and high rigidity.

As a result of diligent research to achieve the above object, the present inventors have made a resin containing a styrene- (meth) acrylic acid-based resin, a polypropylene-based resin, a polystyrene-based resin, and a hydrogenated styrene-butadiene-based resin. It has been found that the above-mentioned problems can be solved by the composition, and the present invention has been completed. That is, the present invention is as shown below.

[1] The present invention is a resin composition containing a styrene- (meth) acrylic acid-based resin, a polypropylene-based resin, a polystyrene-based resin, and a hydrogenated styrene-butadiene-based resin.

[2] In the present invention, the styrene- (meth) acrylic acid-based resin contains 69 to 97% by mass of a styrene monomer unit, 3 to 16 parts by mass of a (meth) acrylic acid monomer unit, and (meth). It is preferably composed of a styrene- (meth) acrylic acid- (meth) methyl acrylate copolymer having a methyl acrylate monomer unit of 0 to 15% by mass.

[3] In the present invention, the hydrogenated styrene-butadiene resin is hydrogenated with a part of an aliphatic double bond and one or more amino groups are introduced into at least one molecular chain. It is preferably composed of a styrene-butadiene-styrene block copolymer.

[4] In the present invention, a melt mixture containing a part of the styrene-butadiene-styrene block copolymer and the styrene- (meth) acrylic acid- (meth) methyl acrylate copolymer previously melt-kneaded. And the polypropylene-based resin or the polystyrene-based resin in contact with the molten mixture.

[5] In the present invention, at least one part of the resin selected from the group consisting of the styrene- (meth) acrylic acid-based resin, the polypropylene-based resin, and the polystyrene-based resin is derived from scraps of resin molded products. It is preferably a resin.

[6] In the present invention, with respect to a total of 100 parts by mass of the styrene- (meth) acrylic acid-based resin 10 to 40% by mass, the polypropylene-based resin 45 to 87% by mass, and the polystyrene-based resin 3 to 15% by mass. It is preferable that the hydrogenated styrene-butadiene resin is contained in an amount of 3 to 15 parts by mass.

[7] In the present invention, with respect to a total of 100 parts by mass of the styrene- (meth) acrylic acid-based resin 10 to 25% by mass, the polypropylene-based resin 2 to 5% by mass, and the polystyrene-based resin 70 to 90% by mass. It is preferable that the hydrogenated styrene-butadiene resin is contained in an amount of 3 to 15 parts by mass.

[8] The present invention is a masterbatch used for preparing the resin composition according to any one of the above [1] to [7].
It contains the hydrogenated styrene-butadiene resin and at least one resin selected from the group consisting of the styrene- (meth) acrylic acid resin, the polypropylene resin and the polystyrene resin. Master Badge.

[9] The present invention is a sheet obtained from the resin composition according to any one of the above [1] to [7].

According to the present invention, it is possible to provide a resin composition having both excellent impact resistance and high rigidity.

According to the present invention, even in a system containing a styrene- (meth) acrylic acid-based resin, which has low compatibility with a polystyrene-based resin, phase separation between the resins is suppressed, and excellent impact resistance and high rigidity are achieved. It is possible to provide a resin composition that is compatible with both.

According to the present invention, scraps containing styrene- (meth) acrylic acid-based resin, which has low compatibility with polystyrene-based resin, are reworked, and phase separation between the resins is suppressed, resulting in excellent impact resistance. It is possible to provide a resin composition having both high rigidity and high rigidity.

FIG. 1 is a drawing showing a transmission electron micrograph image of a sample formed by using the resin composition of Comparative Example 1. FIG. 2 is a drawing showing a transmission electron micrograph image of a sample formed by using the resin composition of Example 1.

Hereinafter, embodiments of the present invention (hereinafter referred to as “the present embodiment”) will be described in detail, but the present invention is not limited to the following description and is variously modified within the scope of the gist thereof. Can be carried out.

"Resin composition"
The resin composition of the present embodiment contains a styrene- (meth) acrylic acid-based resin, a polypropylene-based resin, a polystyrene-based resin, and a hydrogenated styrene-butadiene-based resin.
Thereby, it is possible to provide a resin composition having both excellent impact resistance and high rigidity. In particular, even in a system containing a styrene- (meth) acrylic acid-based resin, which has low compatibility with a polystyrene-based resin, phase separation between the resins is suppressed to achieve both excellent impact resistance and high rigidity. Since it is possible to provide a resin composition, it is useful for recycling offcuts such as trimming loss.

Conventionally, when a container is manufactured from a so-called heat-resistant PSP sheet containing, for example, a styrene- (meth) acrylic acid-based resin and a polystyrene-based resin, 20% to 20% of the heat-resistant PSP sheet is produced according to the shape of the container to be manufactured. About 30% of the scraps were generated. And, as mentioned above, since the styrene- (meth) acrylic acid-based resin has low compatibility with the polystyrene-based resin, it is said that about 20% to 30% of the scraps could not be reworked and were discarded. Was the actual situation. Therefore, as in the present invention, in the embodiment in which the resin composition as a whole contains a styrene- (meth) acrylic acid-based resin, a polypropylene-based resin, a polystyrene-based resin, and a hydrogenated styrene-butadiene-based resin, the resins are used with each other. It was confirmed that excellent impact resistance and high rigidity can be achieved at the same time by suppressing phase separation (= improving dispersibility). Therefore, in a preferred embodiment of the present embodiment, the scraps or used materials that have been discarded after punching the container can be reused as the raw material of the resin composition, so that the scraps or used materials can be reused. The product can be recovered in high yield with respect to the reduction of raw materials. As a method for recovering scraps or used materials that have been discarded after punching the container, conventionally known methods such as manual dismantling and machine sorting can be appropriately adopted.
Hereinafter, each component will be described in detail.

<Styrene- (meth) acrylic acid resin>
The resin composition of the present embodiment contains a styrene- (meth) acrylic acid-based resin. When the polystyrene-based resin composition contains a styrene- (meth) acrylic acid-based resin, the heat resistance is improved. In particular, when used in combination with a polystyrene-based resin (for example, a rubber-modified polystyrene-based resin) and a hydrogenated styrene-butadiene-based resin, dispersibility is improved, and a synergistic effect of achieving both excellent impact resistance and high rigidity is achieved. Is demonstrated. In particular, even in a system containing a styrene- (meth) acrylic acid-based resin, which has low compatibility with a polystyrene-based resin, it is possible to suppress phase separation between the resins and achieve both excellent impact resistance and high rigidity. Therefore, it is useful for rework technology for recycling scraps such as trimming loss. As a result, scraps containing styrene- (meth) acrylic acid-based resin, which has low compatibility with polystyrene-based resin, may be used as a raw material.

The styrene- (meth) acrylic acid-based resin in the resin composition in the present embodiment is the total of styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrogenated styrene-butadiene-based resin. The content is 5 to 40 parts by mass, preferably 7 to 35 parts by mass, and more preferably 10 to 30 parts by mass with respect to 100 parts by mass.

In the present specification, the "styrene- (meth) acrylic acid-based resin" is a copolymer indispensably containing a styrene-based monomer unit and a (meth) acrylic acid-based monomer unit. The (meth) acrylic acid-based monomer is preferably at least one selected from the group consisting of a (meth) acrylic acid monomer unit and a (meth) acrylic acid ester monomer unit. These styrene- (meth) acrylic acid-based resins may be used alone or in combination of two or more.

As used herein, the term "styrene-based monomer unit" means a repeating unit derived from a styrene-based monomer, and more specifically, the styrene-based monomer is subjected to a polymerization reaction or a cross-linking reaction to cause the monomer. A structural unit in which the unsaturated double bond inside becomes a single bond. The meaning of the other "monomer unit" has the same meaning as described above.
As the structure of the styrene- (meth) acrylic acid-based resin, both a random structure and a block structure can be used, and a random copolymer is preferable.

The styrene- (meth) acrylic acid-based resin in the present invention is not particularly limited, and may be a commercially available or synthesized styrene- (meth) acrylic acid-based resin alone, or a styrene- (meth) acrylic acid-based resin. It may be a material containing resin. Therefore, the origin of the styrene- (meth) acrylic acid-based resin, which is the raw material of the resin composition of the present embodiment, is not limited. Examples of the material containing the styrene- (meth) acrylic acid-based resin include used food packages, containers such as food containers; electric appliances such as microwave ovens, air conditioners, televisions, refrigerators, and washing machines; And not only used OA equipment, but also scraps (or skeletons) produced in the manufacturing process can be used.

In the present embodiment, at least one part of the resin selected from the group consisting of styrene- (meth) acrylic acid-based resin, polypropylene-based resin, and polystyrene-based resin may be a resin derived from scraps of a resin molded product. preferable. That is, a part of the resin constituting the resin composition of the present embodiment may be reused from the scrap material or the used material. In the present embodiment, when the resin composition according to the present invention is produced for the purpose of reusing the offcuts or used materials, the masterbatch described later is mixed with the offcuts or used materials. You may.

The scrap material or used material in the present invention is not particularly limited as long as it contains a styrene- (meth) acrylic acid-based resin and a polystyrene-based resin, and the type of scrap material to be used (foam or biaxially stretched sheet). The composition of the offcuts changes according to such factors.

For example, the preferred composition ratio of the offcuts is 10 to 70% by mass of styrene- (meth) acrylic acid-based resin (SMAA) and rubber-modified polystyrene-based resin (HIPS) with respect to the total amount of offcuts (100% by mass). ) A resin having 5 to 50% by mass, polystyrene (GPPS) 10 to 40% by mass, and polypropylene 1 to 20% by mass.

Further, the composition ratio of the scrap material of another preferable example is styrene- (meth) acrylic acid-based resin (SMAA) 40 to 65% by mass and rubber-modified polystyrene-based resin with respect to the total amount of the scrap material (100% by mass). (HIPS) 5 to 30% by mass, polystyrene (GPPS) 10 to 26% by mass, polypropylene 1 to 20% by mass. Another preferable composition ratio of the scrap material is styrene- (meth) acrylic acid-based resin (SMAA) 85-99.5% by mass, rubber-modified polystyrene-based, with respect to the total amount of the scrap material (100% by mass). Resin (HIPS) A resin having 0.5 to 15% by mass.

The styrene- (meth) acrylic acid-based resin (SMAA) contained in the offcuts or used materials that can be used in the present embodiment contains about 85 to 97% by mass of a styrene monomer unit and a methacrylic acid-based monomer. Unit: preferably about 3 to 15% by mass. The weight average molecular weight (Mw) of the styrene- (meth) acrylic acid-based resin (SMAA) is preferably about 100,000 to 200,000.

The rubber-modified polystyrene-based resin (HIPS) contained in the offcuts or used materials that can be used in the present embodiment may be one kind or a mixture of two or more kinds, and contains rubber-like polymer particles in the HIPS. The amount (= rubber amount) is preferably 4 to 15% by mass. The volume average particle diameter (D50) of the rubber-like polymer particles is preferably 0.7 to 3.0 μm. A preferred embodiment of the rubber-modified polystyrene-based resin (HIPS) contained in the offcuts or used materials that can be used in the present embodiment is a mixture of two types of HIPS, and one HIPS has a rubber amount of about about. 11 to 13%, volume average particle size (D50) of about 0.8 to 1.5 μm, while HIPS of the other has a rubber amount of about 5 to 7%, volume average particle size (D50) of about 2 to 2.8 μm. be.

The weight average molecular weight (Mw) of polystyrene (GPPS) contained in the offcuts or used materials that can be used in this embodiment is preferably about 80,000 to 350,000. More specifically, the weight average molecular weight (Mw) of polystyrene (GPPS) when rubber-modified polystyrene resin (HIPS) is mixed in the offcuts is preferably 80,000 or more and 300,000 or less. On the other hand, when the scrap material does not contain the rubber-modified polystyrene resin (HIPS), the weight average molecular weight (Mw) of polystyrene (GPPS) is preferably 200,000 or more and 350,000 or less.

The polypropylene contained in the offcuts or used materials that can be used in the present embodiment is preferably a homopolymer of propylene, and the MFR of the propylene is preferably about 0.1 to 15.

In the present disclosure, the melt mass flow rate of the rubber-modified polystyrene-based resin is a value measured under the condition of 200 ° C. and 5 kg load in accordance with JIS K 7210-1.

Examples of the (meth) acrylic acid monomer used in the styrene- (meth) acrylic acid-based resin in the present invention include methacrylic acid, acrylic acid, maleic anhydride, maleic acid, fumaric acid, and itaconic acid.

The (meth) acrylic acid ester monomer used for the styrene- (meth) acrylic acid-based resin in the present invention is a (meth) acrylic acid ester monomer having an alkyl chain having 1 to 6 carbon atoms as an ester substituent. Is preferable. When the (meth) acrylic acid-based monomer is represented by the chemical formula (1): CH ₂ = C (R ¹ ) -C (= O) -OR ² , the chemical formula (1) is R. ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or an ester substituent (a linear or branched alkyl group having 1 to 6 carbon atoms), and R ² is an ester substituent. In the case of, the (meth) acrylic acid-based monomer corresponds to the (meth) acrylic acid ester monomer.

The alkyl chain having 1 to 6 carbon atoms contains a linear, branched or cyclic alkyl group. Specific examples of the (meth) acrylic acid ester monomer include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, and n- (meth) acrylate. Examples thereof include butyl, s-butyl (meth) acrylate, isobutyl (meth) acrylate, and t-butyl (meth) acrylate. Among these, from an industrial point of view, the (meth) acrylic acid ester monomer is methyl (meth) acrylate, n-butyl (meth) acrylate, s-butyl (meth) acrylate, and (meth) acrylic acid. It is preferably isobutyl and t-butyl (meth) acrylate.

Examples of the styrene-based monomer used in the styrene- (meth) acrylic acid-based resin in the present invention include styrene, α-methylstyrene, α-methyl-p-methylstyrene, ο-methylstyrene, m-methylstyrene, and p. -Examples include methyl styrene, vinyl toluene, ethyl styrene, isobutyl styrene, and t-butyl styrene or styrene derivatives such as bromo styrene and inden. Styrene is particularly preferable from an industrial point of view. These styrene-based monomers can be used alone or in combination of two or more.

In the styrene- (meth) acrylic acid-based resin, the content of the styrene-based monomer unit in the entire styrene- (meth) acrylic acid-based resin is preferably 69 to 97% by mass, more preferably 69 to 94%. It is by mass, more preferably 74 to 91% by mass, and even more preferably 77 to 88% by mass. When the content of the styrene-based monomer unit is less than 69% by mass, the fluidity of the resin decreases, while when it exceeds 97% by mass, the methacrylic acid monomer unit and the methyl methacrylate monomer unit described later are used. The desired amount cannot be present.

In the styrene- (meth) acrylic acid-based resin, the content of the acrylic acid-based monomer unit in the entire styrene- (meth) acrylic acid-based resin is preferably 3 to 16% by mass, more preferably 6 to 6 to 16% by mass. It is 16% by mass, more preferably 7 to 14% by mass, and even more preferably 9 to 13% by mass. (Meta) acrylic acid plays a role in improving heat resistance. If the content of the acrylic acid-based monomer unit is less than 3% by mass, the effect of improving heat resistance is insufficient, while if it exceeds 16% by mass, gelled substances in the resin increase and the appearance becomes poor. Further, it is not preferable because it causes a decrease in the fluidity of the resin and a decrease in the mechanical properties.

In the styrene- (meth) acrylic acid-based resin, the content of the (meth) acrylic acid monomer unit in the entire styrene- (meth) acrylic acid-based resin is preferably 0 to 15% by mass, more preferably. It is 2 to 12% by mass, and even more preferably 3 to 10% by mass. Further, in a preferable form of the styrene- (meth) acrylic acid-based resin, the content of the (meth) acrylic acid ester monomer unit in the entire styrene- (meth) acrylic acid-based resin is preferably 0 to 15% by mass. It is more preferably 2 to 12% by mass, and even more preferably 3 to 10% by mass. However, the total content of the (meth) acrylic acid monomer unit and the (meth) acrylic acid ester monomer unit in the entire styrene- (meth) acrylic acid-based resin is preferably 0 to 15% by mass. It is more preferably 2 to 12% by mass, and even more preferably 3 to 10% by mass. When the content exceeds 15% by mass, the fluidity of the resin tends to decrease and the water absorption tends to increase, which is not preferable.

In the present invention, the styrene- (meth) acrylic acid-based resin contains 81 to 97% by mass of a styrene monomer unit, 3 to 12% by mass of a (meth) acrylic acid monomer unit, and methyl (meth) acrylic acid. It is preferably composed of a styrene- (meth) acrylic acid- (meth) acrylic acid methyl copolymer having a monomer unit of 0 to 7% by mass.

The (meth) acrylic acid ester monomer is used to suppress the dehydration reaction of the (meth) acrylic acid-based monomer by the molecular interaction with the (meth) acrylic acid-based monomer, and the resin machine. It can be used to improve the target strength. Furthermore, the (meth) acrylic acid ester monomer also contributes to the improvement of resin properties such as weather resistance and surface hardness.

When the (meth) acrylic acid-based monomer (unit) and the (meth) acrylic acid ester monomer (unit) are bonded side by side, a high-temperature, high-vacuum devolatilization device may be used depending on the conditions. A dealcohol reaction may occur and a six-membered cyclic acid anhydride may be formed. The styrene- (meth) acrylic acid-based resin of the present embodiment may contain this 6-membered cyclic acid anhydride, but since it reduces the fluidity, less 6-membered cyclic acid anhydride is produced. Is preferable.

In the present embodiment, examples of preferable forms of the styrene- (meth) acrylic and the acid-based resin include a styrene-based monomer unit, a (meth) acrylic acid monomer unit, and a (meth) acrylic acid ester unit. It is preferably a copolymer (A1) having a weight unit (hereinafter referred to as a copolymer (A1)). The copolymer (A1) is not particularly limited, and is, for example, a styrene-acrylic acid-methyl acrylate copolymer, a styrene-acrylic acid-ethyl acrylate copolymer, and a styrene-acrylic acid-acrylic acid. Co., Ltd., propyl copolymer, styrene-acrylic acid-isopropyl acrylate copolymer, styrene-acrylic acid-t-butyl acrylate copolymer, acrylate-n-butyl acrylate copolymer, acrylate-isobutyl acrylate Polymer, acrylate-acrylic acid s-butyl copolymer, styrene-acrylic acid-n-butyl acrylate copolymer, styrene-methacrylic acid-methyl acrylate copolymer, styrene-methacrylic acid-ethyl acrylate Polymer, styrene-methacrylic acid-propyl acrylate copolymer, styrene-methacrylic acid-isopropyl acrylate copolymer, styrene-methacrylic acid-t-butyl acrylate copolymer, styrene-methacrylic acid-isobutyl acrylate Polymer, styrene-methacrylic acid-acrylic acid s-butyl copolymer, styrene-methacrylic acid-n-butyl acrylate copolymer, styrene-methacrylic acid-methyl methacrylate copolymer, styrene-methacrylic acid-methacrylic acid Ethyl copolymer, styrene-methacrylic acid-propyl methacrylate copolymer, styrene-methacrylic acid-isopropyl methacrylate copolymer, styrene-methacrylic acid-t-butyl methacrylate copolymer, styrene-methacrylic acid-metharyl acid Examples thereof include an isobutyl copolymer, a styrene-methacrylic acid-methacrylic acid s-butyl copolymer, a styrene-methacrylic acid-n-butyl methacrylate copolymer and the like.

In the present embodiment, as another example of the preferred embodiment of the styrene- (meth) acrylic acid-based resin, a styrene-based monomer unit and one or more (meth) acrylic acid ester monomer units are used. , Is a repeating unit, and is preferably a copolymer (hereinafter, copolymer (A2)). The above-mentioned copolymer (A2) is not particularly limited, and is, for example, a styrene-methyl acrylate copolymer, a styrene-ethyl acrylate copolymer, a styrene-propyl acrylate copolymer, and a styrene-acrylic acid. Isopropyl copolymer, styrene-t-butyl acrylate copolymer, styrene-s-butyl acrylate copolymer, styrene-isobutyl acrylate copolymer, acrylate-n-butyl acrylate copolymer, styrene- Methyl methacrylate-methyl acrylate copolymer, styrene-methyl methacrylate-ethyl acrylate copolymer, styrene-methyl methacrylate-propyl acrylate copolymer, styrene-methyl methacrylate-isopropyl acrylate copolymer, Styrene-methyl methacrylate-t-butyl acrylate copolymer, styrene-methyl methacrylate-isobutyl acrylate copolymer, styrene-methyl methacrylate-s-butyl acrylate copolymer, and styrene-methyl methacrylate- Examples thereof include an n-butyl copolymer acrylate.

In the present embodiment, as another example of the preferred embodiment of the styrene- (meth) acrylic acid-based resin, a styrene-based monomer unit, one or more (meth) acrylic acid monomer units, and one or more (meth) acrylic acid monomer units are used. It is preferable that the copolymer has the above-mentioned as a repeating unit (hereinafter referred to as a copolymer (A3)). The copolymer (A3) is not particularly limited, and examples thereof include a styrene-acrylic acid copolymer and a styrene-methacrylic acid copolymer.

In the present embodiment, the polymer having a styrene-based monomer unit and a (meth) acrylic acid-based monomer unit is a styrene-based monomer unit with respect to all the monomer units of the copolymer. , The total ratio of the (meth) acrylic acid-based monomer units is preferably 95% by mass or more, and more preferably 98% by mass or more.

The molecular weight or molecular weight distribution of the styrene- (meth) acrylic acid-based resin is not particularly limited, but the weight average molecular weight (Mw) is preferably 10,000 or more and 500,000 or less, and more preferably 20,000 or more and 350,000 or less. If the molecular weight is less than 10,000, the impact strength of the composition may decrease, and if it exceeds 500,000, the dispersibility of the styrene- (meth) acrylic acid-based resin in the composition decreases, and the mechanical strength, especially the folding resistance, is reduced. The strength decreases.
The method for measuring the weight average molecular weight in the present invention is the method described in the "Examples" column.

The melt mass flow rate of the styrene- (meth) acrylic acid-based resin is preferably 0.3 to 7.0 g / 10 min, and particularly preferably 0.5 to 5.0 g / 10 min. The melt mass flow rate of the styrene- (meth) acrylic acid-based resin is a value measured at 200 ° C. and a load of 5 kg according to JIS K 7210-1.

In the present embodiment, the polymerization method of the styrene- (meth) acrylic acid-based resin is not particularly limited, but for example, a bulk polymerization method or a solution polymerization method can be preferably adopted as the radical polymerization method. The polymerization method mainly includes a polymerization step of polymerizing a polymerization raw material (monomer component) and a devolatile step of removing volatile components such as unreacted monomers and polymerization solvent from the polymerization product.
Hereinafter, an example of a styrene- (meth) acrylic acid-based resin polymerization method that can be used in this embodiment will be described.
When a polymerization raw material is polymerized to obtain a styrene- (meth) acrylic acid-based resin, a polymerization initiator and a chain transfer agent are typically contained in the polymerization raw material composition.

Examples of the polymerization initiator used for the polymerization of the styrene- (meth) acrylic acid-based resin include organic peroxides such as 2,2-bis (t-butylperoxy) butane and 1,1-bis (t-butylperoxy). ) Cyclohexane, peroxyketals such as n-butyl-4,4-bis (t-butylperoxy) valerate, dialkyl peroxides such as di-t-butyl peroxide, t-butyl peroxide, dicumyl peroxide, acetyl peroxide , Diacyl peroxides such as isobutyryl peroxide, peroxydicarbonates such as diisopropylperoxydicarbonate, peroxyesters such as t-butylperoxyacetate, ketone peroxides such as acetylacetone peroxide, and hydroperoxides such as t-butylhydroperoxide. Kind etc. can be mentioned. From the viewpoint of decomposition rate and polymerization rate, 1,1-bis (t-butylperoxy) cyclohexane is particularly preferable.

Examples of the chain transfer agent used for the polymerization of the styrene- (meth) acrylic acid-based resin include α-methylstyrene linear dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, and n-octyl mercaptan.

As a method for polymerizing the styrene- (meth) acrylic acid-based resin, solution polymerization using a polymerization solvent can be adopted, if necessary. Examples of the polymerization solvent used include aromatic hydrocarbons such as ethylbenzene and dialkyl ketones such as methyl ethyl ketone, which may be used alone or in combination of two or more. Other polymerization solvents such as aliphatic hydrocarbons can be further mixed with aromatic hydrocarbons as long as the solubility of the polymerization product is not reduced. It is preferable to use these polymerization solvents in a range not exceeding 25 parts by mass with respect to 100 parts by mass of all the monomers. When the amount of the polymerization solvent exceeds 25 parts by mass with respect to 100 parts by mass of all the monomers, the polymerization rate tends to be remarkably lowered and the mechanical strength of the obtained resin tends to be greatly lowered. It is preferable to add 5 to 20 parts by mass with respect to 100 parts by mass of all the monomers before the polymerization because the quality can be easily made uniform and the polymerization temperature can be controlled.

In the present embodiment, the apparatus used in the polymerization step for obtaining the styrene- (meth) acrylic acid-based resin is not particularly limited, and may be appropriately selected according to the polystyrene-based resin described later or a known polymerization method. For example, when bulk polymerization is adopted, a polymerization apparatus in which one or a plurality of completely mixed reactors are linked can be used. Further, there are no particular restrictions on the devolatilization process. When bulk polymerization is adopted, the polymerization is finally advanced until the unreacted monomer is preferably 50% by mass or less, more preferably 40% by mass or less, and the volatile components of the unreacted monomer or the like are removed. Devolatile treatment by a known method. More specifically, for example, a normal volatilizer such as a flash drum, a twin-screw evaporator, a thin film evaporator, an extruder and the like can be used, but a devolatilizer having a small retention portion is preferable. The temperature of the devolatile treatment is usually about 190 to 280 ° C, more preferably 190 to 260 ° C. The pressure of the devolatilization treatment is usually about 0.13 to 4.0 kPa, preferably 0.13 to 3.0 kPa, and more preferably 0.13 to 2.0 kPa. As the devolatile method, for example, a method of removing volatile matter by reducing the pressure under heating and a method of removing volatile matter through an extruder designed for the purpose of removing volatile matter are desirable.

<Polypropylene resin>
The resin composition of the present embodiment contains a polypropylene-based resin. In particular, even in a system containing a styrene- (meth) acrylic acid-based resin, which has low compatibility with a polystyrene-based resin, it is possible to suppress phase separation between the resins and achieve both excellent impact resistance and high rigidity. Therefore, it is useful for rework technology for recycling scraps such as trimming loss. Therefore, it is preferable to use scraps containing polypropylene-based resin as a raw material.

In the present embodiment, the polypropylene-based resin is not particularly limited, and a homopolymer of a propylene-based monomer, a random polymer of propylene and another monomer, a block copolymer, or the like is used. Further, the polypropylene-based resin in the present invention includes a polypropylene-based resin having a linear structure (also referred to as linear PP) and a polypropylene-based resin having a branched structure (also referred to as branched PP). These propylene-based resins may be one kind or a mixture of two or more kinds.

The partial structure of the polypropylene-based resin according to the present invention may have steric regularity (tacticity). Specifically, it may have any stereoregularity of isotactic, syndiotactic and atactic, and may have a plurality of blocks having any of these stereoregularities.

The content of the polypropylene-based resin in the resin composition of the present embodiment can be appropriately changed depending on the purpose of use. More specifically, in the case of a form having a high content of polypropylene-based resin, the total content of styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrogenated styrene-butadiene-based resin is 100. The content of the polypropylene-based resin is 50 to 95 parts by mass, preferably 55 to 90 parts by mass, and more preferably 65 to 85 parts by mass with respect to parts by mass.

On the other hand, when the content of the polypropylene-based resin is low, the total content of the styrene- (meth) acrylic acid-based resin, the polypropylene-based resin, the polystyrene-based resin, and the hydrogenated styrene-butadiene-based resin is 100 parts by mass. On the other hand, the content of the polypropylene-based resin is 1 part by mass or more and less than 50 parts by mass, preferably 3 to 45 parts by mass, and more preferably 5 to 40 parts by mass.

For example, when the viewpoints of heat resistance, hinge characteristics, low temperature impact resistance, etc. are emphasized, the content of the polypropylene-based resin is styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrogenated. The total content of the styrene-butadiene resin is 50 to 95 parts by mass, preferably 60 to 95 parts by mass with respect to 100 parts by mass.

For example, when the viewpoints of dimensional stability, high synthesis, impact resistance, etc. are emphasized, the content of the polypropylene-based resin is styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrogenated resin. The total content of the styrene-butadiene resin is 100 parts by mass, preferably 1 to 50 parts by mass, preferably 1 to 40 parts by mass.

The polypropylene-based resin in the present embodiment is not particularly limited, and may be a commercially available or synthesized polypropylene-based resin alone, or may be a material containing a polypropylene-based resin. Therefore, the origin of the polypropylene-based resin which is the raw material of the resin composition of the present embodiment is not limited. Materials containing the polystyrene-based resin include, for example, used food packages, containers such as food containers; electric appliances such as microwave ovens, air conditioners, televisions, refrigerators, and washing machines; and used OA equipment. Not only the scraps (also referred to as skeletons) produced in the manufacturing process can be used.

The propylene-based monomer constituting the polypropylene-based resin is not particularly limited, but for example, a propylene homopolymer obtained by polymerizing only propylene, a random copolymer obtained by copolymerizing a small amount of ethylene, and a rubber component having a homo-random weight. Examples thereof include a block copolymer uniformly and finely dispersed in a coalescence. Propylene is particularly preferable from an industrial point of view. As the propylene-based monomer, these can be used alone or in combination.

The polypropylene-based resin in the present invention includes polypropylene, a propylene-α-olefin random copolymer which is a random copolymer of propylene and α-olefin, and propylene-α which is a block copolymer of propylene and α-olefin. -Examples include olefin block copolymers. Examples of the α-olefin used for the copolymer include ethylene, 1-butene, 1-hexene, 4-methyl / 1-pentene, 1-octene and the like.

In the present embodiment, the melt flow rate (MFR) of the propylene-based resin is easy to mold and is preferably 0.1 g / 10 min or more, and more preferably 0.3 g / 10 min or more. Further, it is preferably 15 g / 10 min or less, and more preferably 12 g / 10 min or less. The melt mass flow rate (g / 10 minutes) of the polypropylene-based resin was measured under a load condition of 230 ° C. and 2.16 kg as shown in the column of Examples.

<Polystyrene resin>
The resin composition of the present embodiment contains a polystyrene-based resin. By containing the polystyrene-based resin, the rigidity of the composition as a whole is improved. In particular, even in a system containing a styrene- (meth) acrylic acid-based resin, which has low compatibility with a polystyrene-based resin, it is possible to suppress phase separation between the resins and achieve both excellent impact resistance and high rigidity. Therefore, it is useful for rework technology for recycling scraps such as trimming loss. Therefore, it is preferable to use scraps containing polystyrene-based resin as a raw material.

In the present embodiment, the polystyrene-based resin is a homopolymer of a styrene-based monomer or another monomer ((meth) acrylic-based) that can be copolymerized with the styrene-based monomer, if necessary. It can be a copolymer with (excluding monomers).

The polystyrene-based resin is a rubber in which particles of a rubber-like polymer are dispersed in a matrix of a polystyrene-based resin, in other words, a rubber obtained by polymerizing a styrene-based monomer in the presence of the rubber-like polymer. It can also be a modified polystyrene-based resin.

The content of the polystyrene-based resin in the resin composition of the present embodiment can be appropriately changed depending on the purpose of use. More specifically, in the case of a form having a high content of polystyrene-based resin, the total content of styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrogenated styrene-butadiene-based resin is 100. The content of the polystyrene-based resin is 50 to 95 parts by mass, preferably 55 to 90 parts by mass, and more preferably 65 to 85 parts by mass with respect to parts by mass.

On the other hand, in the case where the content of the polystyrene-based resin is low, the total content of the styrene- (meth) acrylic acid-based resin, the polypropylene-based resin, the polystyrene-based resin, and the hydrogenated styrene-butadiene-based resin is 100 parts by mass. On the other hand, the content of the polystyrene-based resin is 1 part by mass or more and less than 50 parts by mass, preferably 3 to 45 parts by mass, and more preferably 5 to 40 parts by mass. When the polystyrene-based resin is present in the resin composition of the present embodiment, the heat resistance, mechanical properties, and the like of the molded product obtained from the resin composition can be ensured.

For example, when the viewpoints of dimensional stability, high synthesis, impact resistance, etc. are emphasized, the polystyrene-based resin is styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrated styrene. -The total content of the butadiene resin is 50 to 95 parts by mass, preferably 60 to 95 parts by mass with respect to 100 parts by mass.

For example, when the viewpoints of heat resistance, hinge characteristics, low temperature impact resistance, etc. are emphasized, the polystyrene-based resin is styrene- (meth) acrylic acid-based resin, polypropylene-based resin, polystyrene-based resin, and hydrogenated styrene-. The total content of the butadiene resin is 1 to 50 parts by mass, preferably 1 to 40 parts by mass with respect to 100 parts by mass.

The polystyrene-based resin in the present embodiment is not particularly limited, and may be a commercially available or synthesized polystyrene-based resin alone, or may be a material containing a polystyrene-based resin. Therefore, the origin of the polystyrene-based resin which is the raw material of the resin composition of the present embodiment is not limited. Materials containing the polystyrene-based resin include, for example, used food packages, containers such as food containers; electric appliances such as microwave ovens, air conditioners, televisions, refrigerators, and washing machines; and used OA equipment. Not only the scraps (also referred to as skeletons) produced in the manufacturing process can be used.

The styrene-based monomer constituting the polystyrene-based resin is not particularly limited, and examples thereof include styrene, α-methylstyrene, paramethylstyrene, ethylstyrene, propylstyrene, butylstyrene, chlorostyrene, and bromostyrene. .. Styrene is particularly preferable from an industrial point of view. As the styrene-based monomer, these can be used alone or in combination.

Further, as a copolymer of another monomer copolymerizable with the styrene-based monomer (excluding the (meth) acrylic acid-based monomer), particularly if it can be copolymerized with the styrene-based monomer. Not limited.

The content of the styrene-based monomer unit in the polystyrene-based resin is preferably 70% by mass or more, more preferably, when the total amount of the monomer units constituting the polystyrene-based resin is 100% by mass. Is 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 97% by mass or more. If the content is less than 70% by mass, the moldability and fluidity of the polystyrene-based resin, which are characteristic of the polystyrene-based resin, are lowered, which is not preferable.

When the polystyrene-based resin is a copolymer of a styrene-based monomer and a copolymerizable other monomer other than the (meth) acrylic acid-based monomer, the polystyrene-based resin may be used. The upper limit of the content of the styrene-based monomer unit is preferably 98% by mass, more preferably 95% by mass. When the polystyrene-based resin is a homopolymer of a styrene-based monomer such as polystyrene, the polystyrene-based resin is preferably composed of a styrene-based monomer unit, but for example, a styrene-based monomer unit. It is permissible that the monomer units other than the above are contained in an amount of 5% by mass or less, preferably 3% by mass or less, and more preferably 1% by mass or less.

When the polystyrene-based resin is a rubber-modified polystyrene-based resin, it refers to the content of the styrene-based monomer unit in the polystyrene-based resin excluding the rubber-like polymer.

The content of the styrene-based monomer unit and the other monomer-based unit in the polystyrene-based resin when the other monomers are copolymerized is when the resin is measured by a nuclear magnetic resonance measuring device ( ¹ H-NMR). It can be obtained from the integral ratio of the spectra of.

When the polystyrene-based resin is a rubber-modified polystyrene-based resin, as the rubber-like polymer, polybutadiene, polyisoprene, natural rubber, polychloroprene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like can be used. Among them, 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. Further, as the structure of the styrene-butadiene copolymer, both a random structure and a block structure can be used. One or more of these rubber-like polymers can be used.

The rubber-like polymer contained in the rubber-modified polystyrene-based resin may be one in which the polystyrene-based resin is encapsulated inside and the polystyrene-based resin is grafted on the outside.

Examples of such rubber-modified polystyrene-based resins include HIPS (high impact polystyrene), ABS resin (acrylonitrile-butadiene-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), and AES resin (Acrylonitrile-acrylic rubber-styrene copolymer). Acrylonitrile-ethylene propylene rubber-styrene copolymer) and the like. Further, it is preferable to use scraps containing rubber-modified polystyrene-based resin.

The content of the rubber component contained in the rubber-modified polystyrene-based resin is not particularly limited, but is preferably 2 to 10% by mass, more preferably 2.5 to 8% by mass, based on 100% by mass of the rubber-modified polystyrene-based resin. %. If the content of the rubber component is less than 2% by mass, the impact resistance is lowered and the molded product is easily cracked. Further, when the content of the rubber-like polymer exceeds 10% by mass, the mechanical strength and appearance tend to decrease.
In the present disclosure, the content of the rubber component contained in the rubber-modified polystyrene-based resin is a value calculated by using a pyrolysis gas chromatograph.

The average particle size of the rubber-like polymer dispersed particles contained in the rubber-modified polystyrene-based resin is not particularly limited, but is preferably 0.5 to 5.0 μm, more preferably 1.0 to 4.0 μm. be. If the average particle size of the rubber-like polymer dispersed particles is smaller than 0.5 μm, the impact resistance of the resin composition tends to be difficult to obtain, and if it is larger than 5.0 μm, the mechanical strength and appearance tend to deteriorate.

In the present disclosure, the average particle size of the dispersed particles of the rubber-like polymer contained in the rubber-modified polystyrene-based resin is, as described in Examples, a particle size distribution measuring machine (Multisizer III Beckman. Refers to the volume-based median diameter using (manufactured by Coulter).

The weight average molecular weight (Mw) of the rubber-modified polystyrene-based resin is not particularly limited, but is preferably in the range of 50,000 to 400,000, and more preferably in the range of 80 to 350,000. If the weight average molecular weight is less than 50,000, the impact strength tends to decrease, and if it exceeds 400,000, the moldability tends to deteriorate.

In the present disclosure, the weight average molecular weight (Mw) of the rubber-modified polystyrene-based resin is a value measured by gel permeation chromatography (GPC), and more specifically, in the section of [Example] described later. It is a value measured by the procedure described.

The melt mass flow rate of the rubber-modified polystyrene-based resin is not particularly limited, but is preferably in the range of 1.0 to 20 g / 10 min, and more preferably in the range of 1.5 to 16 g / 10 min. If it is lower than 1.0 g / 10 min, the moldability deteriorates, and if it exceeds 20 g / 10 min, the appearance of the molded product tends to be poor.

In the present disclosure, the melt mass flow rate of the rubber-modified polystyrene-based resin is a value measured under the condition of 200 ° C. and 5 kg load in accordance with JIS K 7210-1.
An example of a method for producing a rubber-modified polystyrene-based resin that can be used in the resin composition of the present embodiment is shown.

In a typical embodiment, the rubber-modified polystyrene-based resin polymerizes a styrene-based monomer in the presence of a rubber-like polymer to form a sea-island structure in which the rubber-like polymer is dispersed in the styrene-based polymer. It can be manufactured by a method including forming. There are no particular restrictions on the polymerization method of the styrene-based monomer, and ordinary bulk polymerization, solution polymerization, suspension polymerization and the like can be carried out using a solution in which rubber is dissolved in the styrene-based monomer. Further, it is preferable to appropriately select and use a solvent or a chain transfer agent for adjusting the melt flow rate. As the solvent, toluene, ethylbenzene, xylene and the like can be used. The amount of the solvent used is not particularly limited, but is preferably in the range of 0 to 50% by mass with respect to 100% by mass of the total amount of the polymerization raw material liquid. As the chain transfer agent, n-dodecyl mercaptan, t-dodecyl mercaptan, α-methylstyrene dimer and the like are used, and α-methylstyrene dimer is preferable. The amount of the chain transfer agent used is preferably 0.01 to 2% by mass, more preferably 0.03 to 1% by mass, and further preferably 0.05 to 0.2 with respect to 100% by mass of the total amount of the polymerization raw material liquid. It is in the range of% by mass. The polymerization reaction temperature is preferably in the range of 80 to 200 ° C, more preferably 90 to 180 ° C. When the reaction temperature is 80 ° C. or higher, the productivity is good and it is industrially suitable. On the other hand, when the reaction temperature is 200 ° C. or lower, it is preferable because a large amount of low molecular weight polymer can be avoided. If the target molecular weight of the styrene-based polymer cannot be adjusted only by the polymerization temperature, it may be controlled by the amount of the initiator, the amount of the solvent, the amount of the chain transfer agent, or the like. The reaction time is generally 0.5 to 20 hours, preferably 2 to 10 hours. If the reaction time is 0.5 hours or more, the reaction proceeds well, while if the reaction time is 20 hours or less, the productivity is good and industrially suitable.

In the above production method, the particle size of the dispersed particles of the rubber-like polymer in the rubber-modified polystyrene-based resin can be controlled by the rotation speed of the stirrer in the reactor, and the amount of toluene insoluble content is started. The swelling index for toluene insoluble in toluene can be controlled by the temperature of the extruder of the recovery system.

The amount of the rubber-like polymer of the rubber-modified polystyrene-based resin can be controlled by adjusting the content and the polymerization rate of the rubber-like polymer in the raw material so as to reach the target content. In the present embodiment, the rubber-modified polystyrene-based resin can be produced by the above-mentioned production method, but as another method, a polystyrene resin or the like that does not contain a rubber-like polymer in the rubber-modified polystyrene-based resin obtained by the above-mentioned production method or the like. It can also be produced by mixing and diluting the polystyrene-based resin of.

Examples of the organic peroxide used as a polymerization initiator include peroxyketals, dialkyl peroxides, diacyl peroxides, peroxydicarbonates, peroxyesters, ketone peroxides, hydroperoxides and the like. Can be mentioned.
As the polymerization solvent, ethylbenzene, toluene, xylene and the like can be used.

In the present embodiment, the object of the present invention is not impaired as necessary at any stage before and after the recovery step in producing the rubber-modified polystyrene-based resin, or at the stage of extrusion processing and molding processing of the rubber-modified polystyrene-based resin. Various additives in the range, such as ultraviolet absorbers, light stabilizers, antioxidants such as hindered phenols, phosphorus and sulfur, lubricants, plasticizers such as liquid paraffin, antistatic agents, flame retardants, various dyes. And pigments, fluorescent whitening agents, light diffusing agents, and selective wavelength absorbers may be added.

<Hydrogenated styrene-butadiene resin>
The resin composition of the present embodiment contains a hydrogenated styrene-butadiene resin.
This makes it possible to improve the mechanical strength of the molded product obtained by molding the resin composition. Further, by being contained in the resin composition in a predetermined content together with the above-mentioned styrene- (meth) acrylic acid-based resin, it is rich in dispersibility and has excellent impact resistance and rigidity. In particular, by adding the above-mentioned styrene- (meth) acrylic acid-based resin and the hydrogenated styrene-butadiene-based resin to the polystyrene-based resin and the resin composition containing the polypropylene-based resin, the resin composition can be obtained. As a whole, it was confirmed that the mechanical strength was improved.

The hydrogenated styrene-butadiene resin is a styrene-butadiene copolymer containing a conjugated diene and a styrene-based monomer unit as a repeating unit and having all or part of the unsaturated bond of the conjugated diene hydrogenated. Refers to a polymer.

In the present embodiment, the content of the styrene-based monomer unit in the hydrogenated styrene-butadiene-based resin is preferably 10% by mass or more and 70% by mass or less, and more preferably 20% by mass or more and 60% by mass or less. When the content of the styrene-based monomer unit is less than 10% by mass, the rigidity of the resin composition tends to decrease, while when the content of the styrene-based monomer unit exceeds 70% by mass, the impact resistance is high. The improvement tends to be low.

In the present embodiment, the hydrogenation ratio of the double bond based on the conjugated diene compound of the hydrogenated styrene-butadiene resin is preferably 80% or more, more preferably 90% or more. If the hydrogenation rate is less than 80%, the rigidity of the resin composition tends to decrease.
The hydrogenation rate was calculated from ¹ H-NMR peak value and its area ratio and ¹³ C-NMR peak value as described in the column of Examples.

In the present embodiment, the content of the hydrogenated styrene-butadiene resin in the resin composition is styrene- (meth) acrylic acid resin, polypropylene resin, polystyrene resin, and hydrogenated styrene-butadiene. The total content of the based resin is 0.1 to 20 parts by mass, preferably 0.5 to 15 parts by mass with respect to 100 parts by mass. When the content is 20 parts by mass or less, the strength of the molded product obtained from the resin composition can be further improved, and when the content is 0.1 parts by mass or more, it can be obtained from the resin composition. The rigidity of the molded body can be maintained.

Further, when at least one part selected from the group consisting of styrene- (meth) acrylic acid-based resin, polypropylene-based resin and polystyrene-based resin is a resin derived from scraps of a resin molded product, heat resistance and hinge characteristics. In order to emphasize the viewpoint of low temperature impact resistance, the resin composition of styrene- (meth) acrylic acid-based resin 10 to 25% by mass, polypropylene-based resin 60 to 85% by mass, and polystyrene-based resin 5 to 15% by mass. It is preferable that the hydrogenated styrene-butadiene resin is contained in an amount of 3 to 15 parts by mass with respect to 100 parts by mass of the substance.

Further, when at least one part selected from the group consisting of styrene- (meth) acrylic acid-based resin, polypropylene-based resin and polystyrene-based resin is a resin derived from scraps of a resin molded product, dimensional stability and high performance are achieved. In order to emphasize the viewpoints of synthesis, impact resistance, etc., styrene- (meth) acrylic acid-based resin 10 to 25% by mass, polypropylene-based resin 2 to 5% by mass, and polystyrene-based resin 70 to 90% by mass. It is preferable that the hydrogenated styrene-butadiene resin is contained in an amount of 3 to 15 parts by mass with respect to 100 parts by mass of the composition.

In the present embodiment, the hydrogenated styrene-butadiene resin is a hydrogenated block obtained by hydrogenating a non-hydrogenated block copolymer containing a conjugated diene compound and a styrene monomer as repeating units. It is preferably a copolymer. The conjugated diene compound is a diolefin having a pair of conjugated double bonds, and examples thereof include 1,3-butadiene and 2-methyl-1,3-butadiene (isoprene). Examples of the styrene-based monomer include styrene, α-methylstyrene, and divinylbenzene. The most common hydrogenated block copolymer is a hydrogenated block copolymer composed of 1,3-butadiene and styrene, which is also called SEBS.

The hydrogenated styrene-butadiene resin in the present invention may have an amino group in the molecular chain constituting the resin. That is, the hydrogenated styrene-butadiene resin in the present invention is styrene-butadiene-styrene in which a part of the aliphatic double bond is hydrogenated and at least one amino group having one or more molecular chains is introduced. More preferably, it is composed of a block copolymer. If the polymer chain of the styrene-butadiene resin has an amino group, the polymers are likely to interact with each other, and it is considered that the dispersibility of each component in the composition is further improved.

Examples of the styrene-butadiene-styrene block copolymer include Tough Tech (trade name MP10 or trade name P1000) manufactured by Asahi Kasei Chemicals Co., Ltd. The presence of the amine introduced in the polymer chain can be identified by a known method such as NMR or IR.

Further, as a preferred embodiment of the present embodiment, a styrene-butadiene-styrene block copolymer and styrene which have been melt-kneaded in advance for the purpose of inducing an interaction such as a chemical bond with a styrene- (meth) acrylic acid-based resin. -A melt mixture containing a (meth) acrylic acid resin (eg, styrene- (meth) acrylic acid- (meth) methyl acrylate copolymer) and a polypropylene resin and / or polystyrene contacted with the melt mixture. It may be in the form of having a styrene resin.

That is, a styrene-butadiene-styrene block copolymer and a styrene- (meth) acrylic acid-based resin (for example, a styrene- (meth) acrylic acid- (meth) methyl acrylate copolymer) are melt-mixed in advance. By mixing the mixture with the polypropylene-based resin and / or the polystyrene-based resin, the dispersibility of the styrene- (meth) acrylic acid-based resin in the resin composition is improved, or the styrene- (meth) with respect to the polystyrene-based resin is improved. It is considered that the compatibility of the acrylic acid-based resin can be improved and the phase separation between the resins can be suppressed.

In the present embodiment, the method of block copolymerization of a conjugated diene and a styrene-based monomer for producing a hydrogenated styrene-butadiene resin and the method of hydrogenating the obtained block copolymer are A known method can be used.

In the present embodiment, the weight average molecular weight of the hydrogenated styrene-butadiene resin is not particularly limited. For example, when the viewpoint of molding processability is emphasized, the weight average molecular weight of the hydrogenated styrene-butadiene resin is preferably 600,000 or less. The weight average molecular weight of the hydrogenated styrene-butadiene resin is more preferably 70,000 to 500,000, still more preferably 80,000 to 400,000.
On the other hand, when the impact resistance of the entire resin composition is emphasized, the weight average molecular weight of the hydrogenated styrene-butadiene resin may be 600,000 or more.

In the present embodiment, the hydrogenated styrene-butadiene resin may be modified with a compound having a functional group. Examples of the functional group include a carboxyl group, an acid anhydride group, an isocyanato group, an epoxy group, a silanol group, an alkoxysilane group and the like.
In the present embodiment, a commercially available product can be used as the hydrogenated styrene-butadiene resin. An example is Tough Tech (trade name) manufactured by Asahi Kasei Chemicals Co., Ltd.

<Other ingredients>
Various general additives can be added to the resin composition of the present embodiment within a range not exceeding the gist of the present invention in order to achieve known actions and effects. For example, mold release agents, lubricants, antioxidants, UV absorbers, plasticizers, dyes, pigments, antistatic agents, anti-fog agents, various fillers, etc. may be added to achieve the desired effect. Can be done.
The above-mentioned various additives in the resin composition are preferably 1.0% by mass or less, more preferably 0.8% by mass or less, still more preferably more preferably 0.8% by mass or less with respect to 100% by mass of the resin composition. It is 0.5% by mass or less.

<Masterbatch for manufacturing resin compositions>
In the present embodiment, at least one part of the resin selected from the group consisting of styrene- (meth) acrylic acid-based resin, polypropylene-based resin, and polystyrene-based resin may be reused of scraps or used materials. good. At this time, in the case of producing the resin composition according to the present invention in the present embodiment, the masterbatch may be produced by mixing scraps or used materials.

The masterbatch is a masterbatch used for preparing the resin composition of the present invention, and is a hydrogenated styrene-butadiene resin, the styrene- (meth) acrylic acid resin, and the polypropylene resin. And at least one resin selected from the group consisting of the polystyrene-based resin is preferably contained.

Since the masterbatch in the present embodiment indispensably contains a hydrogenated styrene-butadiene resin, the dispersibility between different resins can be improved. Then, in the present embodiment, the hydrogenated styrene-butadiene resin 35 to 65% by mass, the styrene- (meth) acrylic acid resin 10 to 40% by mass, based on the total amount (100% by mass) of the master batch. It is preferable to contain 0 to 15% by mass of the polypropylene-based resin and 10 to 40% by mass of the polystyrene-based resin, 43 to 57% by mass of the hydrogenated styrene-butadiene-based resin, and 18 to 32% by mass of the styrene- (meth) acrylic acid-based resin. It is more preferable to contain% by mass, 0 to 7% by mass of the polypropylene-based resin, and 18 to 32% by mass of the polystyrene-based resin.

<Manufacturing method of resin composition>
In the present embodiment, the method for producing the resin composition is to blend, melt, knead, and granulate a styrene- (meth) acrylic acid-based resin, a polypropylene-based resin, a polystyrene-based resin, and a hydrogenated styrene-butadiene-based resin. The method is not particularly limited, and a method commonly used in the production of a resin composition can be used. For example, each of the above components mixed (mixed) with a drum tumbler, a Henschel mixer, etc. is melted and kneaded using a Banbury mixer, a single-screw extruder, a twin-screw extruder, a kneader, etc., and granulated with a rotary cutter, a fan cutter, etc. The resin composition can be obtained by the above. The resin temperature in melting and kneading is preferably 180 to 240 ° C. In order to reach the target resin temperature, it is preferable to set the cylinder temperature of the extruder or the like to a temperature 10 to 20 ° C. lower than the resin temperature. If the resin temperature is less than 180 ° C., mixing is insufficient, which is not preferable. On the other hand, if the resin temperature exceeds 240 ° C., thermal decomposition of the resin occurs, which is not preferable.

A preferred method for producing the resin composition of the present invention is to mix a hydrogenated styrene-butadiene resin and a styrene- (meth) acrylic acid resin in a mass ratio of 1: 2 to 2: 1 and then mix them. If necessary, a step of melt-kneading at 200 to 260 ° C. to prepare a melt mixture using a twin-screw extruder, and

100 to 2000 parts by mass of a material selected from the group consisting of 100 parts by mass of chips obtained by crushing scraps or used materials of a resin molded product, and polystyrene-based resin and polypropylene-based resin, which are virgin materials added as necessary. And the process of preparing a resin mixture that is a mixture of
It comprises a step of mixing 1 to 20 parts by mass of the melt mixture with 100 parts by mass of the resin mixture to prepare a resin composition.

As the polystyrene-based resin and the polypropylene-based resin used as the virgin material, the description contents of the polystyrene-based resin and the polypropylene-based resin described above can be incorporated.
As the scrap material or used material of the resin molded product, the description contents of the scrap material or used material described above can be incorporated.

<Molded body>
The molded product of the present embodiment can be obtained by molding the resin composition of the above-described embodiment of the present invention. The molded product of the present embodiment is not particularly limited as long as it is obtained by molding the resin composition of the above-described embodiment of the present invention, but it is preferable that the molded product has a portion having a thickness of 1 mm or less. .. The above resin composition can be preferably used in a molded product having a portion having a thickness of 1 mm or less.

The molded product of the present embodiment is not particularly limited, but is preferably a container or a sheet. The container of the present embodiment may be manufactured (molded) directly from the resin composition, or may be manufactured by further molding a sheet obtained by molding the resin composition. Further, the sheet of the present embodiment can be used for manufacturing (molding) not only a container but also another molded body.

The sheet of the present embodiment is a non-effervescent extruded sheet, and the thickness is not particularly limited, but can be, for example, 1.0 mm or less, preferably 0.2 to 0.8 mm.

Further, the sheet of the present embodiment may be a sheet formed only by ordinary low-magnification roll stretching, but in particular, after stretching about 1.3 to 7 times with a roll, it is 1.3 to 7 times with a tenter. A sheet that has been stretched to some extent is preferable from the viewpoint of strength.

The sheet of the present embodiment may be used in a multi-layered manner with a styrene-based resin such as a polystyrene resin, or in addition to or in place of the layer of the styrene-based resin or the like, a multi-layered structure with a resin other than the styrene-based resin. It may be converted and used. Examples of the resin other than the styrene resin include PP resin, PP / PS resin, PET resin, nylon resin and the like.
The container of the present embodiment is a container obtained by injection blow molding using the above resin composition, or a container obtained by molding the above sheet.

Specifically, the container obtained by injection blow molding according to the present embodiment is not particularly limited, and examples thereof include a container for storing or accommodating a beverage such as a lactic acid bacterium beverage or a food such as fermented milk. , It can be a cylindrical vertical type having a flange surface at the opening and having the opening at the upper part. The container can be 50 to 120 mm in height, 30 to 60 mm in diameter, and 0.2 to 0.8 mm in thickness.

Further, the container obtained by molding the above-mentioned sheet of the present embodiment is not particularly limited, and examples thereof include a container for containing a lunch box lid or a side dish, which is formed from a sheet or a multilayer body containing the sheet. ..

In the present embodiment, the manufacturing method for obtaining a molded product from the resin composition is not particularly limited, and the molded product can be manufactured by a known molding method, for example, extrusion molding or injection molding. Specifically, the extrusion molding process includes, for example, extrusion molding, calender molding, hollow molding, extrusion foam molding, deformed extrusion molding, laminating molding, inflation molding, T-die film molding, sheet molding, vacuum molding, pressure molding, and direct molding. Blow molding and the like can be mentioned. In addition, examples of the injection molding process include injection molding, RIM molding, injection foam molding, injection blow molding, injection stretch blow molding and the like.

In the present embodiment, the method for manufacturing the sheet among the molded bodies is not particularly limited, but for example, the sheet is extruded by a short-screw or twin-screw extruder equipped with a T-die, and the sheet is extruded by a uniaxial stretching machine or a biaxial stretching machine. The method of picking up the product can be mentioned.
Further, in the present embodiment, the method for manufacturing a container obtained by molding from a sheet is not particularly limited, and examples thereof include vacuum forming.

Further, in the present embodiment, the method for manufacturing the container obtained by injection blow molding is not particularly limited, and the container can be molded by a known method. Specifically, in injection blow molding, an intermediate (for example, a bottomed parison) is first molded from the resin composition by injection molding, and then the intermediate is cored in a softened state (a male mold for injection molding). A hollow molded body (for example, a container) can be molded by moving it into a blow-molded mold while it is still attached to the mold, and then inflating it to the inner wall surface of the blow-molded mold by sending pressure from the core.

In the above molding method, at the stage of blow molding the intermediate, the mold temperature is preferably 20 to 70 ° C, more preferably 25 to 65 ° C, still more preferably 30 to 60 ° C. ..
The temperature of the rubber-modified polystyrene is preferably 180 to 280 ° C, more preferably 200 to 260 ° C.
The ratio of the volume of the container to the volume of the intermediate (volume stretching ratio) is preferably 1.5 to 7 times, more preferably 2 to 5 times.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above examples and can be appropriately modified.

1. 1. "Evaluation method of resin characteristics"
(1) Measurement of the content of each monomer unit in the styrene- (meth) acrylic acid-based resin and each monomer unit in the hydrogenated styrene-butadiene-based resin Nuclear magnetic resonance ( ¹ H-NMR) ) Quantified from the integral ratio of the spectrum measured by the device.
Sample preparation: 75 mg of resin was dissolved in 0.75 mL of d1 _- chloroform.
Measuring equipment: JEOL JNM ECA-500
Measurement conditions: Measurement temperature 60 ° C, observation nucleus 1H, integration count 32 ^times , repetition time 45 seconds

(2) Measurement of Weight Average Molecular Weight The weight average molecular weight (Mw) of the polystyrene-based resin was measured by gel permeation chromatography (GPC) under the following conditions.
Equipment: Tosoh HLC-8220
Sorting column: TSK gel Super HZM-H (inner diameter 4.6 mm) manufactured by Tosoh is connected in series. Guard column: TSK guard volume Super HZ-H manufactured by Tosoh
Measuring solvent: Tetrahydrofuran (THF)
Sample concentration: 5 mg of the measured sample was dissolved in 10 mL of solvent, and filtration was performed with a 0.45 μm filter.
Injection volume: 10 μL
Measurement temperature: 40 ° C
Flow velocity: 0.35 mL / min Detector: Ultraviolet absorption detector (UV-8020 manufactured by Tosoh, wavelength 254 nm)
To create a calibration curve, 11 types of TSK standard polystyrene manufactured by Tosoh (F-850, F-450, F-128, F-80, F-40, F-20, F-10, F-4, F-2) , F-1, A-5000) was used. A calibration curve was created using an approximate expression of a linear straight line.

(3) Measurement of Melt Mass Flow Rate (MFR) The melt mass flow rate (g / 10 minutes) of the produced polystyrene-based resin (composition) is measured under a load condition of 200 ° C. and 5.00 kg in accordance with ISO1133. bottom.
The melt mass flow rate (g / 10 minutes) of the polypropylene-based resin (composition) was measured at 230 ° C. under a load condition of 2.16 kg in accordance with ISO1133.

(4) Measurement of Vicat softening temperature The Vicat softening temperature of the produced polystyrene-based resin composition was measured in accordance with ISO306. The load was 50 N and the heating rate was 50 ° C./h.

(5) Measurement of flexural modulus The produced polystyrene-based resin composition was injection-molded into an ISO type A test piece, and the flexural modulus was measured according to ISO178.

(6) Measurement of DuPont Impact Strength Dart (weight 226.5 g) and dent (dent diameter 9.6 mm) of the striking core whose tip diameter was 9.5 mm for which the DuPont impact strength was measured according to ASTM D 2974. ) Is contact-fixed between the cradle having a thickness of 0.4 mm, a weight of 100 g is dropped on the dart from an appropriate height (maximum 100 cm), and an extruded plate which is a test piece is used. Then, the energy for cracking (weight of weight x height of drop) was obtained from the height of 50% fracture. The unit is kg · cm. As the test piece, a 0.3 mm thick sheet obtained by extruding the produced resin composition at 260 ° C. with a 20 mm sheet extruder was used as the test piece.

(7) Calculation of hydrogenation rate Measured by ¹ H-NMR using the polymer sampled at each step of the polymerization process of the modified block copolymer before hydrogenation and during the polymerization.
For vinyl bonds, the integral values per 1H of each bond mode are calculated from the integral values of the signals attributable to 1,4-bonds and 1,2-bonds, and then 1,4-bonds and 1,2-bonds are used. It was calculated from the ratio of.
Further, the hydrogenation rate was measured by ¹ H-NMR using the polymer after hydrogenation in the same manner as above. For the hydrogenation rate, the integral value of the signal derived from the residual double bond of 4.5 to 5.5 ppm and the signal derived from the hydrogenated conjugated diene was calculated, and the ratio was calculated.

2. 2. "Ingredients used"
The raw materials used in Examples 1 to 7 and Comparative Examples 1 to 4 below are as follows.
The styrene- (meth) acrylic acid-based resin (1) is a styrene-methacrylic acid copolymer of "G9001" manufactured by PS Japan Co., Ltd. (methacrylic acid monomer unit content 8% by mass, methyl methacrylate single amount). Body unit content 0% by mass) was used.

The styrene- (meth) acrylic acid-based resin (2) is a styrene-methacrylic acid-methyl methacrylate copolymer (methacrylic acid monomer unit content 11% by mass, methacrylic acid) of "MM290" manufactured by PS Japan Co., Ltd. Methyl monomer unit content 5% by mass) was used.

As the polypropylene-based resin (1), "Novatec PP FY6C" manufactured by Japan Polypropylene Corporation was used.
As the polystyrene resin (1), "PSJ-polystyrene HIPS 475D" manufactured by PS Japan Corporation was used.
As the polystyrene resin (2), "PSJ-polystyrene HIPS H0103" manufactured by PS Japan Corporation was used.
As the polystyrene resin (3), "PSJ-polystyrene GPPS G9305" manufactured by PS Japan Corporation was used.
As the hydrogenated styrene-butadiene resin (1), "Tough Tech MP10 (modified with a molecular chain single-ended amine)" manufactured by Asahi Kasei Corporation was used.
As the hydrogenated styrene-butadiene resin (2), "Tough Tech P1500 (without modification at one end of the molecular chain)" manufactured by Asahi Kasei Corporation was used.
As the styrene-butadiene-styrene block resin (1), "Toughprene 125" manufactured by Asahi Kasei Corporation was used.

The composition ratio of the scraps of the heat-resistant PSP (polystyrene paper) was 55% by mass of SMAA "G9001" manufactured by PS Japan Corporation, 16% by mass of HIPS, 16% by mass of GPPS, and 13% by mass of polypropylene.

3. 3. "Preparation of resin composition"
<Preparation of melt mixture and resin mixture>
<Preparation of molten mixture (1)>
The hydrogenated styrene-butadiene resin (1) and the styrene- (meth) acrylic acid resin (1) are mixed at a mass ratio of 1: 1 and then melted at 230 ° C. using a 20 mm twin-screw extruder. The melt mixture (1) was prepared by kneading.

<Preparation of molten mixture (2)>
The hydrogenated styrene-butadiene resin (1) and the styrene- (meth) acrylic acid resin (2) are mixed at a mass ratio of 1: 1 and then melted at 230 ° C. using a 20 mm twin-screw extruder. Kneading was performed to prepare a molten mixture (2).

<Preparation of molten mixture (3)>
The hydrogenated styrene-butadiene resin (2) and the styrene- (meth) acrylic acid resin (1) are mixed at a mass ratio of 1: 1 and then melted at 230 ° C. using a 20 mm twin-screw extruder. Kneading was performed to prepare a molten mixture (3).

<Preparation of resin mixture (4)>
Styrene-butadiene-styrene block copolymer (1) and styrene- (meth) acrylic acid resin (1) are mixed at a mass ratio of 1: 1 and then melted at 230 ° C. using a 20 mm twin-screw extruder. The resin mixture (4) was prepared by kneading.

<Mixing with melt mixture (1)-(3) or resin mixture (4)>
Examples 1 to 7 are obtained by mixing the melt mixture (1) to (4) or the resin mixture (4) prepared above, the scrap of the resin molded product, and the polypropylene-based resin or the polystyrene-based resin as follows. And the mixed composition of Comparative Examples 1 to 4 were prepared.

<< Example 1 >>
Melting of 10 parts by mass with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare the resin composition (1) of Example 1.

<< Example 2 >>
10 parts by mass of the melt mixture with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 80% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 20% by mass. (1) was mixed to prepare the resin composition (2) of Example 2.

<< Example 3 >>
Melting of 16 parts by mass with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare the resin composition (3) of Example 3.

<< Example 4 >>
Melting of 10 parts by mass with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (3) was mixed to prepare the resin composition (4) of Example 4.

<< Example 5 >>
Melting of 10 parts by mass with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (2) was mixed to prepare the resin composition (5) of Example 5.

<< Example 6 >>
Melting 16 parts by mass with respect to a mixture (100 parts by mass) in which the polystyrene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare the resin composition (6) of Example 6.

<< Example 7 >>
Melting of 24 parts by mass with respect to a mixture (100 parts by mass) in which the polystyrene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare the resin composition (7) of Example 7.

<< Comparative Example 1 >>
Melting of 2 parts by mass with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare a mixed composition (1) of Comparative Example 1.

<< Comparative Example 2 >>
Melting of 32 parts by mass with respect to the mixture (100 parts by mass) in which the polypropylene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare a mixed composition (2) of Comparative Example 2.

<< Comparative Example 3 >>
10 parts by mass of the resin with respect to the mixture (100 parts by mass) in which the polypropylene-based resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (4) was mixed to prepare a mixed composition (3) of Comparative Example 3.

<< Comparative Example 4 >>
Melting of 2 parts by mass with respect to a mixture (100 parts by mass) in which the polystyrene resin (1) is 70% by mass and the chips obtained by crushing the scraps of heat-resistant PSP (polystyrene paper) are 30% by mass. The mixture (1) was mixed to prepare a mixed composition (4) of Comparative Example 4.

4. "Manufacturing of molded products"
A dumbbell-shaped molded piece obtained by injection-molding the resin compositions (1) to (7) prepared in Examples 1 to 16 and the mixed composition prepared in Comparative Examples 1 to 4, respectively, under the injection conditions described later. Was used to evaluate the flexural modulus and the bicut softening temperature. Further, the resin compositions (1) to (7) prepared in Examples 1 to 16 and the mixed compositions prepared in Comparative Examples 1 to 4 are respectively molded into a sheet (thickness 0) under the extrusion conditions described later. A DuPont impact test was performed using (1.3 mm).

<Injection molding>
The obtained pellet-shaped styrene resin composition or resin composition was supplied to an EC60N injection molding machine manufactured by Toshiba Machine Co., Ltd. The temperature of the resin melting zone was set to 180 to 220 ° C., and injection was performed in a mold set to 50 ° C. to obtain a dumbbell mold test piece having a thickness of 4 mm.

<Extrusion molding>
The obtained pellet-shaped styrene resin composition or resin composition was supplied to a sheet extruder manufactured by Soken Co., Ltd. with a screw diameter of 30 mm. The temperature of the resin melting zone is set to 220 to 260 ° C., and after melt extrusion from a T die (coat hanger die) with a discharge rate of 10 kg / h, it is crimped to a cast roll or touch roll set at 90 ° C. and has a width of 300 mm. A sheet having a thickness of 0.3 mm was obtained. The results are shown below in Table 1-1, Table 1-2 and 2.

Further, transmission electron micrographs of the molded product formed by using the resin compositions of Comparative Example 1 and Example 1 are shown in FIGS. 1 and 2, respectively. As is clear from comparing the image of Comparative Example 1 shown in FIG. 1 with the image of Example 1 shown in FIG. 2, the molded product using the resin composition of Example 1 has a small area of the resin phase. Therefore, it can be confirmed that each component of the resin composition is well dispersed.

The present invention suppresses phase separation between resins even in a system containing a styrene-acrylic acid copolymer resin (SMAA), which has low compatibility with polystyrene resins, and has excellent impact resistance and high rigidity. Since it is possible to provide a resin composition that achieves both of these factors, it is useful in the field of recycling offcuts such as trimming loss.

Claims (9)

A resin composition containing a styrene- (meth) acrylic acid-based resin, a polypropylene-based resin, a polystyrene-based resin, and a hydrogenated styrene-butadiene-based resin. The styrene- (meth) acrylic acid-based resin contains 69 to 97% by mass of a styrene monomer unit, 3 to 16% by mass of a (meth) acrylic acid monomer unit, and a (meth) methyl acrylic acid monomer unit. The resin composition according to claim 1, which comprises a styrene- (meth) acrylic acid-methyl (meth) acrylic acid copolymer having 0 to 15% by mass. The hydrogenated styrene-butadiene resin is a styrene-butadiene-styrene block in which a part of an aliphatic double bond is hydrogenated and one or more amino groups are introduced into at least one molecular chain. The resin composition according to claim 1 or 2, which is composed of a polymer. A melt mixture containing a part of the styrene-butadiene-styrene block copolymer and the styrene- (meth) acrylic acid- (meth) methyl acrylate copolymer, which has been melt-kneaded in advance, is in contact with the melt mixture. The resin composition according to claim 3, further comprising the polypropylene-based resin or the polystyrene-based resin. Claim 1 that at least one part of the resin selected from the group consisting of the styrene- (meth) acrylic acid-based resin, the polypropylene-based resin, and the polystyrene-based resin is a resin derived from scraps of a resin molded product. The resin composition according to any one of 4 to 4. The water was added to a total of 100 parts by mass of the styrene- (meth) acrylic acid-based resin 10 to 40% by mass, the polypropylene-based resin 45 to 87% by mass, and the polystyrene-based resin 3 to 15% by mass. The resin composition according to any one of claims 1 to 5, which contains 3 to 15 parts by mass of a styrene-butadiene resin. The water was added to a total of 100 parts by mass of the styrene- (meth) acrylic acid-based resin 10 to 25% by mass, the polypropylene-based resin 2 to 5% by mass, and the polystyrene-based resin 70 to 90% by mass. The resin composition according to any one of claims 1 to 5, which contains 3 to 15 parts by mass of a styrene-butadiene resin. A masterbatch used to prepare the resin composition according to any one of claims 1 to 7.
It contains the hydrogenated styrene-butadiene resin and at least one resin selected from the group consisting of the styrene- (meth) acrylic acid resin, the polypropylene resin and the polystyrene resin. Master Badge. A sheet obtained from the resin composition according to any one of claims 1 to 7.

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