JP2017155196A - Resin composition and foam molded body thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition excellent in foamability, heat resistance and fire retardancy.SOLUTION: Provided is a resin composition, to the total (100 pts.mass) of (a) a polyphenylene ether based resin and (b) a polystyrene resin, comprising the (a) component by 10-70 pts.mass and the (b) component by 30-90 pts.mass, and in which rubber having a cis ratio exceeding 96.0% is dispersed. It is preferable that (c) a phosphate ester based compound is included, and the (c) component is included by 7-35 pts.mass to the total (100 pts.mass) of the (a) component and the (b) component.SELECTED DRAWING: None

Description

  The present invention relates to a fat composition having excellent foamability and a foamed molded product thereof.

Conventionally, polyphenylene ether-based resins have been used in home appliances, OA equipment, automobile parts, etc. because they have excellent electrical insulation properties, as well as good heat resistance, hydrolysis resistance, and flame resistance. Yes.
In recent years, in order to reduce the size and precision of resin parts, resin products that are incorporated near heat-generating parts are required to have even better heat resistance and flame retardancy.

  For example, in order to improve the heat resistance of a polyphenylene ether resin, a heat resistant resin composition to which a styrene-methacrylic acid copolymer, a polyphenylene ether resin, and syndiotactic polystyrene are added has been proposed (see Patent Document 1). ).

Japanese Patent Laying-Open No. 2015-71678

In order to obtain a foamed molded article, usually, a combustible gas foaming agent (physical foaming) such as butane or propane, or a foaming agent (chemical foaming) such as sodium bicarbonate or citric acid is often used. However, physical foaming uses high-pressure combustible gas, and large-scale equipment and its management are necessary to ensure safety. Furthermore, in chemical foaming, unreacted foaming agents and decomposition products may remain in the resin and cause discoloration. Although a method using nitrogen gas or carbon dioxide gas is also disclosed, it is necessary to cope with safety in terms of handling high-pressure gas.
In Patent Document 1, such problems of equipment and safety are not taken into account, and foamability cannot be said to be sufficient, and in addition to excellent heat resistance and flame retardancy, polyphenylene ether type which is also excellent in foamability. The present condition is that the resin composition is not known.

  This invention is made | formed in view of the problem of the prior art mentioned above, and aims at providing the resin composition excellent in foamability, heat resistance, and a flame retardance.

As a result of intensive studies in order to solve the above problems, the present inventor, as a result of dispersing a rubber having a specific cis ratio in a resin composition containing a polyphenylene ether resin and a polystyrene resin, high pressure gas injection or It was found that a resin composition that can be foamed without using a chemical foaming agent and that has excellent heat resistance and flame retardancy can be obtained.
Furthermore, it has been found that by using a phosphoric ester compound, flame retardancy is further improved while maintaining a balance of foamability, heat resistance, and flame retardancy.

That is, the present invention is as follows.
[1]
10 to 70 parts by mass of component (a) and 30 to 90 parts by mass of component (b) with respect to the total (100 parts by mass) of (a) polyphenylene ether resin and (b) polystyrene resin, cis ratio A resin composition characterized in that a rubber exceeding 96.0% is dispersed.

[2]
The resin composition according to [1], wherein the cis ratio of the rubber is 96.4% or more.

[3]
[1] or [1] or [c] containing (c) a phosphoric ester compound, and containing 7 to 35 parts by mass of (c) component with respect to the total (100 parts by mass) of component (a) and component (b) 2].

[4]
A foamed molded article comprising the resin composition according to any one of [1] to [3].

  According to the present invention, foaming can be performed without using high-pressure gas injection or a chemical foaming agent, and a resin composition excellent in foamability, heat resistance and flame retardancy can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist.

In the resin composition of the present embodiment, 10 to 70 parts by mass of component (a) and 10 parts by mass of component (b) with respect to the total (100 parts by mass) of (a) polyphenylene ether resin and (b) polystyrene resin. A rubber containing 30 to 90 parts by mass and having a cis ratio exceeding 96.0% is dispersed.
With this configuration, the resin composition of the present embodiment can exhibit a physical property balance excellent in foamability, heat resistance, and flame retardancy.

  In the resin composition of the present embodiment, rubber having a cis ratio exceeding 96.0% is dispersed. The rubber having a cis ratio exceeding 96.0% may be uniformly dispersed or non-uniformly dispersed in the resin composition of the present embodiment.

  In the present specification, “the cis ratio exceeds 96.0%” refers to a rubber having an average cis ratio of all rubbers included in the resin composition of more than 96.0%. Among these, it is more preferable that the cis ratio of all rubbers contained in the resin composition is more than 96.0%.

  In the resin composition of the present embodiment, rubber (such as rubber having a cis ratio exceeding 96.0%) may be included, for example, in the component (b) or may be included separately from the polystyrene-based resin. . Examples of the former include a method using a rubber-modified styrene resin (hereinafter also referred to as an impact-resistant polystyrene resin) in which rubber is dispersed in a matrix made of a polystyrene resin.

  Hereinafter, it describes about the resin composition of the aspect in which rubber | gum is contained in (b) component.

Hereinafter, the components of the resin composition of the present embodiment will be described.
((A) polyphenylene ether resin)
The resin composition of this embodiment contains a polyphenylene ether-based resin (hereinafter sometimes simply referred to as “PPE”) as the component (a). Since it contains a polyphenylene ether-based resin, the resin composition of the present embodiment has excellent heat resistance and flame retardancy.

［式中、Ｒ₁、Ｒ₂、Ｒ₃、及びＲ₄は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１〜７の第一級アルキル基、炭素数１〜７の第二級アルキル基、フェニル基、ハロアルキル基、アミノアルキル基、炭化水素オキシ基、及び少なくとも２個の炭素原子がハロゲン原子と酸素原子とを隔てているハロ炭化水素オキシ基からなる群から選択される一価の基であり、互いに同一でも異なっていてもよい。］ As said polyphenylene ether-type resin, the homopolymer which consists of a repeating unit represented by following General formula (1), the copolymer containing the repeating unit represented by following General formula (1), etc. are mentioned.

[Wherein R ₁ , R ₂ , R ₃ , and R ₄ each independently represent a hydrogen atom, a halogen atom, a primary alkyl group having 1 to 7 carbon atoms, or a secondary alkyl group having 1 to 7 carbon atoms. A monovalent group selected from the group consisting of an alkyl group, a phenyl group, a haloalkyl group, an aminoalkyl group, a hydrocarbonoxy group, and a halohydrocarbonoxy group in which at least two carbon atoms separate a halogen atom and an oxygen atom Which may be the same or different. ]

In the above formula (1), the R _1, R _2, R _3, and R _4, halogen atom, a primary alkyl group having 1 to 7 carbon atoms, a phenyl group, are preferred.
In the above formula (1), examples of the halogen atom represented by R ₁ , R ₂ , R ₃ and R ₄ include a fluorine atom, a chlorine atom and a bromine atom, and a chlorine atom is preferred.
In the above formula _{(1), R 1, R} 2, R 3, and as the primary alkyl group of 1 to 7 carbon atoms represented by R _4, 1 to 6 carbon atoms straight or branched An alkyl group is preferable, and a linear or branched alkyl group having 1 to 3 carbon atoms is more preferable. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a pentyl group, and a hexyl group. An ethyl group is preferred.

The polyphenylene ether resin is not particularly limited, and examples thereof include poly (2,6-dimethyl-1,4-phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), and poly (2,6-dimethyl-1,4-phenylene ether). Homopolymers such as (2-methyl-6-phenyl-1,4-phenylene ether) and poly (2,6-dichloro-1,4-phenylene ether); 2,6-dimethylphenol and other phenols ( For example, copolymers such as copolymers with 2,3,6-trimethylphenol, 2-methyl-6-butylphenol, etc .; In particular, from the viewpoint of the balance between toughness and rigidity when used as a resin composition and easy availability, poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2, A copolymer with 3,6-trimethylphenol is preferred, and poly (2,6-dimethyl-1,4-phenylene ether) is more preferred.
The said polyphenylene ether-type resin may be used individually by 1 type, and may use 2 or more types together.

In addition to the homopolymer and the copolymer, the polyphenylene ether resin includes the homopolymer or the copolymer, a styrene monomer or a derivative thereof, and / or an α, β-unsaturated carboxylic acid or the It may be a known modified polyphenylene ether resin obtained by reacting with a derivative. Here, the graft amount or addition amount of the styrene monomer or derivative and / or α, β-unsaturated carboxylic acid or derivative thereof is 0.01 to 10 mass with respect to 100 mass% of component (a). % Is preferred. Examples of the reaction conditions include, but are not limited to, conditions including, for example, conditions performed in a molten state, a solution state, or a slurry state at a temperature of 80 to 350 ° C. in the presence or absence of a radical generator. .
The polyphenylene ether resin may be a mixture in which the homopolymer and / or the copolymer and the modified polyphenylene ether resin are mixed at an arbitrary ratio.

The reduced viscosity of the polyphenylene ether resin is preferably 0.15 to 2.00 dL / g, more preferably 0.20 to 1.0 from the viewpoints of fluidity, toughness, and chemical resistance during molding. 00 dL / g, more preferably 0.30 to 0.70 dL / g. The reduced viscosity of the polyphenylene ether resin can be adjusted by production conditions such as the amount of catalyst during polymerization, temperature, and polymerization time.
The polyphenylene ether resin may be a mixture of two or more polyphenylene ether resins having different reduced viscosities.

  The polyphenylene ether resin can be produced by a known method. The method for producing PPE is not limited to the following, but, for example, Hay, described in US Pat. No. 3,306,874, uses a complex of cuprous salt and amine as a catalyst, and oxidative polymerization of 2,6-xylenol. A method described in U.S. Pat. Nos. 3,306,875, 3,257,357, 3,257,358, Japanese Patent Publication No. 52-17880, Japanese Patent Laid-Open No. 50-51197, or 63-152628. Etc.

  From the viewpoint of heat resistance and flame retardancy, the content of the component (a) in the resin composition of the present embodiment is 10 to 10 parts by weight when the total amount of the component (a) and the component (b) is 100 parts by mass. 70 parts by mass, preferably 15 to 70 parts by mass, and more preferably 15 to 65 parts by mass. If content of (a) component is the range of 10-70 mass parts, the balance of heat resistance and a flame retardance can fully be made favorable.

  Content of (a) component in the resin composition of this embodiment is 7.4-70 mass% with respect to a resin composition (100 mass%) from a heat resistant, a flame retardance, and a fluid viewpoint. It is preferable that

((B) polystyrene resin)
The resin composition of the present embodiment contains a polystyrene resin as the component (b).
In particular, in an embodiment in which rubber is included in the component (b), an impact-resistant polystyrene resin in which rubber is included in the component (b) is used.

Examples of the polystyrene resins include, but are not limited to, homopolymers of styrene compounds (homostyrene resins); copolymers of two or more styrene compounds, styrene compounds and styrene compounds. And a copolymer such as a copolymer with a compound that can be copolymerized with A; an impact-resistant polystyrene resin.
The said polystyrene resin may be used individually by 1 type, and may use 2 or more types together.

Examples of the styrene compound include, but are not limited to, styrene, α-methylstyrene, 2,4-dimethylstyrene, monochlorostyrene, p-methylstyrene, p-tert-butylstyrene, and ethylstyrene. Etc. Of these, styrene is preferred. The above styrenic compounds may be used alone or in combination of two or more.
The content of the unit derived from the styrene compound in the polystyrene resin is, for example, preferably 50% by mass or more, and more preferably more than 85% by mass.

The compound copolymerizable with the styrenic compound is not limited to the following. For example, methacrylic acid esters such as methyl methacrylate and ethyl methacrylate; unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; Acid anhydrides such as maleic anhydride; and the like. The compounds copolymerizable with the styrenic compound may be used alone or in combination of two or more.
The content of the unit derived from the copolymerizable compound in the polystyrene resin is preferably 20% by mass or less, and 15% by mass or less with respect to 100% by mass of the styrene compound from the viewpoint of balance of physical properties. More preferred.

Examples of the impact-resistant polystyrene resin include, in the presence of rubber, a monomer or monomer mixture containing a styrene compound as an essential component, known block polymerization, block suspension polymerization, solution polymerization, or emulsion polymerization. The resin obtained by doing is mentioned. Among them, a graft copolymer of rubber and a styrene resin is preferable, a dispersed phase (island) of rubber is dispersed in a continuous phase (sea) of the styrene resin, and styrene is further added in the dispersed phase of rubber. A resin having a structure in which a base resin is dispersed is more preferable.
The said impact-resistant polystyrene may be used individually by 1 type, and may use 2 or more types together.

Examples of rubber dispersed in the impact-resistant polystyrene resin include natural rubber; diene rubbers such as polyisoprene, poly (styrene-butadiene), poly (styrene-isoprene), and polybutadiene; and the diene rubber is hydrogenated. Saturated rubber; Isoprene rubber; Chloroprene rubber; Acrylic rubber such as polybutyl acrylate; Ethylene-propylene-diene monomer terpolymer (EPDM); and the like. Among them, natural rubber is preferable.
The said rubber | gum may be used individually by 1 type, and may use 2 or more types together.

The cis ratio of the rubber dispersed in the impact-resistant polystyrene resin is preferably more than 96.0%, more preferably 96.4% or more, from the viewpoint of further improving foamability. More preferably, it is 9% or more.
(B) When the impact resistant polystyrene resin and the polystyrene homopolymer are used in combination as the component, or when the polystyrene resin polymerized using natural rubber and synthetic rubber is used in combination, the heat resistance of the resulting resin composition From the viewpoint of further improving the balance between heat resistance and foamability, the cis ratio of the rubber dispersed in the impact-resistant polystyrene resin is preferably 96.4% or more, more preferably 97.5% or more. Preferably, it is 99.9% or more. In particular, it is more preferable to use only natural rubber having a cis ratio of 99.9% as the rubber.
The cis ratio can be measured by, for example, ¹ H-NMR (absolute method) according to JIS K6239. In the case of mixed rubber, the value obtained by dividing the sum of the product of the cis ratio and the content of each rubber in the mixed rubber by the total content of the mixed rubber is the cis ratio of the mixed rubber (average cis ratio). And

  The content of the rubber having a cis ratio of more than 96.0% in the impact-resistant polystyrene resin is from the viewpoint of obtaining a resin composition having further excellent heat resistance, foamability and flame retardancy. It is preferable that it is 5-50 mass% with respect to 100 mass%, and it is more preferable that it is 8-50 mass%.

The content of the component (b) in the resin composition of the present embodiment is 100 masses of the total amount of the component (a) and the component (b) from the viewpoint of improving the balance of heat resistance, foamability and flame retardancy. Parts, it is 30 to 90 parts by mass, preferably 30 to 85 parts by mass, and more preferably 35 to 85 parts by mass.
In the case of using an impact-resistant polystyrene resin as the component (b) and rubber is included in the component (b), the content of the component (b) refers to the content of the impact-resistant polystyrene. .

((C) Phosphate ester compound)
The resin composition of the present embodiment may further contain (c) a phosphoric ester compound.
When the resin composition of this embodiment contains the component (c), the flame retardancy improving effect by the component (a) and the flame retardancy imparting effect by the component (c) are combined to further improve the flame retardancy. .

［式中、Ｒ¹¹、Ｒ¹²、Ｒ¹³、及びＲ¹⁴は、それぞれ独立して、水素原子、ハロゲン原子、アルキル基、シクロアルキル基、アリール置換アルキル基、アリール基、ハロゲン置換アリール基、及びアルキル置換アリール基からなる群から選択される一価の基を表し、それぞれ同一であっても異なっていてもよい。Ｘはアリーレン基を表す。ｎは０〜５の整数である。］
なお、リン酸エステル系化合物が、上記ｎが異なるリン酸エステル及び／又はその縮合物の混合物である場合、ｎはそれらの平均値を表す。ｎ＝０である場合は、一般式（２）の化合物は、リン酸エステル単量体を示す。
上記リン酸エステル系化合物は、１種を単独で用いてもよいし、２種以上を併用してもよい。 Although the said phosphate ester type compound is not specifically limited, What has an effect as a flame retardant is preferable. The phosphate ester compound is preferably a condensed phosphate ester compound, and more preferably a condensed phosphate ester flame retardant. Although it does not limit to the following as said phosphate ester type compound, For example, the compound phosphate ester represented by following General formula (2), its condensate, etc. are mentioned.

[Wherein, R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ are each independently a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, an aryl-substituted alkyl group, an aryl group, a halogen-substituted aryl group, and Represents a monovalent group selected from the group consisting of alkyl-substituted aryl groups, which may be the same or different. X represents an arylene group. n is an integer of 0-5. ]
In addition, when a phosphate ester type compound is a mixture of the phosphate ester from which said n differs, and / or its condensate, n represents those average values. When n = 0, the compound of the general formula (2) represents a phosphate ester monomer.
The said phosphate ester type compound may be used individually by 1 type, and may use 2 or more types together.

  Representative phosphoric acid ester monomers include, but are not limited to, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, and the like.

  The component (c) is preferably a condensed phosphate ester compound, and more preferably a condensed phosphate ester compound in which n in Formula (2) is 1 to 5. As a condensate of a phosphate ester compound, n can usually take an average value of 1 to 5, but preferably an average value of 1 to 3.

Component (c) is at least one of R ¹¹ , R ¹² , R ^13, and R ¹⁴ from the viewpoints of flame retardancy and heat resistance that are expressed when kneaded into the resin composition of the present embodiment. Are preferably an aryl group, a halogen-substituted aryl group, or an alkyl-substituted aryl group, and more preferably all are an aryl group, a halogen-substituted aryl group, or an alkyl-substituted aryl group. From the same viewpoint, the preferred aryl group, halogen-substituted aryl group, and alkyl-substituted aryl group are preferably a phenyl group, a xylenyl group, a cresyl group, or a halogenated derivative thereof.

  The arylene group of X is preferably a residue obtained by removing two hydroxyl groups from resorcinol, hydroquinone, bisphenol A, biphenol, or a halogenated derivative thereof.

  Examples of the phosphate ester compounds include, but are not limited to, resorcinol-bisphenyl phosphate compounds, bisphenol A-polyphenyl phosphate compounds, bisphenol A-polycresyl phosphate compounds, and the like.

  The content of the component (c) in the resin composition of the present embodiment is the total amount of the component (a) and the component (b) from the viewpoint of obtaining a resin composition that is further excellent in foamability, heat resistance, and flame retardancy. Is preferably 7 to 35 parts by mass, more preferably 7 to 30 parts by mass, and even more preferably 10 to 30 parts by mass. (C) If content of a component is the range of 7-35 mass parts, the balance of foamability, heat resistance, and a flame retardance can be made more fully favorable.

(Other ingredients)
In addition to the components described above, the resin composition of the present embodiment may contain other components as necessary within a range that does not impair the foamability, heat resistance, and flame retardancy of the resin composition.
Examples of the other components include, but are not limited to, for example, antioxidants, metal deactivators, flame retardants (phosphate ester compounds not corresponding to the component (c), ammonium polyphosphate compounds) , Silicone flame retardant, phosphazene flame retardant, etc.), plasticizer (low molecular weight polyethylene, epoxidized soybean oil, polyethylene glycol, fatty acid esters, etc.), weather resistance (light) improver, slip agent, inorganic or organic filling Examples thereof include materials and reinforcing materials (mica, talc, chlorite, glass flakes, glass fibers, wollastonite, carbon fibers, polyacrylonitrile fibers, aramid fibers, etc.), various colorants, release agents and the like.

In this embodiment, it is good also as a resin composition of the aspect in which rubber | gum was included separately from the polystyrene-type resin as above-mentioned.
In an embodiment in which rubber is included separately from the polystyrene resin, the rubber mixed with the polystyrene resin includes the same rubber as the rubber dispersed in the above-mentioned impact-resistant polystyrene resin.
In this embodiment, the rubber having a cis ratio of more than 96.0% dispersed in the resin composition is included separately from the rubber and the polystyrene resin included in the component (b). The average cis ratio of all rubbers including rubber is referred to, and the content of component (b) refers to the total content of polystyrene resin and rubber.
In this embodiment, the content of the rubber having a cis ratio of more than 96.0% in the resin composition is such that the resin composition 100 is obtained from the viewpoint of obtaining a resin composition having more excellent heat resistance, foamability and flame retardancy. It is preferable that it is 11-45 mass% with respect to mass%, and it is more preferable that it is 15-40 mass%.
In this embodiment, the cis ratio of the rubber dispersed in the resin composition exceeds 96.0%, and is preferably 96.4% or more from the viewpoint of foamability. From the viewpoint of obtaining a resin composition with even better foamability, it is more preferable that natural rubber having a cis ratio of 99.9% or more is dispersed in the resin composition.

  The deflection temperature under load measured according to JIS K7191-1 of the resin composition of the present embodiment is preferably 60 to 150 ° C, and more preferably 80 to 140 ° C.

Charpy notched impact strength was measured according to JIS K7111-1 of the resin composition of the present embodiment is preferably 3~20kJ / m ^2, and more preferably 5~18kJ / m ² .

[Method for producing resin composition]
The resin composition of the present embodiment can be produced by melt-kneading the above-described component (a), component (b), and further component (c) as necessary.

  The melt kneader for performing the melt kneading is not limited to the following, for example, a single screw extruder, a multi screw extruder including a twin screw extruder, a roll, a kneader, a Brabender plastograph, a heat melt kneading by a Banbury mixer, etc. Among them, a twin screw extruder is particularly preferable from the viewpoint of kneadability. Specific examples include the ZSK series manufactured by WERNER & PFLEIDERER, the TEM series manufactured by Toshiba Machine Co., Ltd., and the TEX series manufactured by Nippon Steel Works.

  A preferred production method using an extruder will be described below.

  The L / D (barrel effective length / barrel inner diameter) of the extruder is preferably in the range of 20 or more and 60 or less, more preferably 30 or more and 50 or less.

  Although it does not specifically limit about the structure of an extruder, For example, the 1st raw material supply port is provided in the upstream with respect to the flow direction of a raw material, the 1st vacuum vent is provided downstream from this, and the 2nd raw material supply port is provided downstream ( If necessary, third and fourth raw material supply ports may be further provided), and a second vacuum vent provided downstream thereof is preferable. In particular, a kneading section is provided upstream of the first vacuum vent, a kneading section is provided between the first vacuum vent and the second raw material supply port, and between the second to fourth raw material supply ports and the second vacuum vent. A kneading section is more preferable.

  Although the raw material supply method to the said 2nd-4th raw material supply port is not specifically limited, Extruder side opening is open rather than only addition supply from the open port of an extruder 2nd-4th raw material supply port. The method of supplying from the mouth using a forced side feeder is preferable because it tends to be supplied more stably.

  In particular, when the raw material contains powder and it is desired to reduce the generation of cross-linked products and carbides due to the thermal history of the resin, a method using a forced side feeder supplied from the extruder side is more preferable. A method of providing at the fourth raw material supply port and supplying powders of these raw materials in a divided manner is more preferable.

  Moreover, when adding a liquid raw material, the method of adding in an extruder using a plunger pump, a gear pump, etc. is preferable.

  And the upper open port of the extruder 2nd-4th raw material supply port can also be used as an open port for extracting the air to carry.

  Although it does not specifically limit regarding the melt-kneading temperature and screw rotation speed in the melt-kneading process of a resin composition, Usually, melt-kneading temperature shall be 240-310 degreeC, and screw rotation speed shall be 100-1200 rpm.

  Furthermore, when reducing the generation of cross-linked products and carbides due to thermal history in the presence of oxygen in the resin, the oxygen concentration of each process line in the route of addition of each raw material to the extruder is kept below 1.0% by volume. It is preferable. Although it does not specifically limit as a specific example of the said addition path | route, The structure of a weight type feeder holding a piping, a refill tank, piping, a supply hopper, a twin screw extruder can be mentioned in an order from a stock tank. The method for maintaining the low oxygen concentration as described above is not particularly limited, but a method of introducing an inert gas into individual process lines with improved airtightness is effective. Usually, it is preferable to introduce nitrogen gas and maintain the oxygen concentration at less than 1.0% by volume.

  In the method for producing the resin composition described above, when the polyphenylene ether-based resin as the component (a) is in a powder form (volume average particle size is less than 10 μm), the resin composition of the present embodiment is obtained using a twin screw extruder. In producing, the effect of further reducing the residue in the screw of the twin-screw extruder, and further in the resin composition obtained by the above-described production method, the effect of reducing the occurrence of sunspot foreign matter, carbides, etc. Bring.

As a specific method for producing the resin composition of the present embodiment, an extruder in which the oxygen concentration of each raw material supply port is controlled to be less than 1.0% by volume is used, and any one of the following methods 1 to 5 is performed. It is preferable to do.
1. The total amount of the component (a) contained in the resin composition of the present embodiment, a part of the component (b) is melt-kneaded (first kneading step), and the optional components are added to the kneaded product obtained in the first kneading step. (C) The total amount of component (c) and the remaining amount of component (b) are supplied in the order of melt kneading (second kneading step). A manufacturing method in which an object is in a molten state.
2. The total amount of component (a) and the total amount of component (b) contained in the resin composition of the present embodiment are melt-kneaded (first kneading step), and as an optional component for the kneaded product obtained in the first kneading step. A manufacturing method in which the entire amount of component (c) is supplied and melt-kneaded (second kneading step), wherein the kneaded product is in a molten state from the first kneading step to the second kneading step.
3. A total amount of component (a) contained in the resin composition of the present embodiment, a part of component (b) is melt-kneaded to produce pellets, and the total amount of component (c) as optional components in the pellets, ( b) A production method in which the components are supplied in the order of the remaining amount and melt kneaded.
4). A pellet is prepared by melt-kneading the total amount of component (a), a part of component (b), and the total amount of component (c) as an optional component contained in the resin composition of the present embodiment. b) A production method in which the remaining amount of the component is supplied and melt kneading is performed.
5. The manufacturing method of melt-kneading the whole quantity of (a) component contained in the resin composition of this embodiment, the whole quantity of (b) component, and the whole quantity of (c) component as an arbitrary component.

  In particular, the resin composition obtained by the production method 1 is superior to the resin composition obtained by the production methods 2 to 5 above in the mixing property of the polyphenylene ether resin as the component (a). ) It is possible to prevent thermal deterioration of the component. For this reason, the production amount of the resin composition per hour can be increased, there is no melt, the generation of cross-linked products and carbides due to thermal history can be reduced, and the resin composition with excellent productivity and quality Is more preferable.

  As described above, from the viewpoint of improving the productivity and the quality of the obtained resin composition, the method for producing a resin composition according to this embodiment includes the component (a) contained in the resin composition of this embodiment. The total amount, the first kneading step in which a part of the component (b) is melt-kneaded, the kneaded product obtained by the first kneading step, the total amount of the component (c) and the remaining amount of the component (b) And a second kneading step in which a resin composition is obtained by melt kneading, and the kneaded product is preferably in a molten state in the first kneading step to the second kneading step. Here, “the kneaded product is in a molten state from the first kneading step to the second kneading step” is intended to exclude an aspect in which the component (a) is once melted and pelletized and then melted again. .

[Foamed molded product]
The foamed molded product of the present invention contains the above-described resin composition.
A desired foam can be obtained by molding the resin composition of the present embodiment. Examples of the molding method include, but are not limited to, molding methods such as extrusion molding, sheet molding, hot press molding, rotational molding, and lamination molding, without using high-pressure gas injection or a foaming agent. A foam can be obtained. Specific examples of the molding method include a method by T-die extrusion, a method of obtaining a multilayer sheet of a foamed molded article containing the resin composition of the present embodiment and a layer made of another resin by multilayer T-die extrusion. Can be mentioned. The expansion ratio is preferably less than 5 times from the viewpoint of impact.
The foamed molded product of the present embodiment can also be produced by an extrusion tubular method (also called inflation method). In the extruded tubular method, the thickness of the foamed molded product can be controlled by appropriately selecting the temperature of the parison from the temperature range of 50 to 290 ° C. so that the parison coming out of the cylinder does not cool immediately. It is extremely important to make uniform. Moreover, the multilayer sheet of the foaming molding containing the resin composition of this embodiment and the layer which consists of another resin can also be obtained by the inflation method using a multilayer die.
From the viewpoint of reducing the occurrence of cross-linked products and carbides due to the thermal history of the resin in the presence of oxygen, it is preferable to use a molding machine having an oxygen concentration of less than 1% by volume even during film molding.

  The foamed molded product of the present embodiment preferably has a flame retardance of not less than HB, more preferably not less than V-2, as evaluated according to UL94 vertical combustion test.

  In the foamed molded product of the present embodiment, the specific gravity measured according to JIS K7112 is preferably 1.03 or less, and more preferably 1.00 or less.

  The foam molded body of this embodiment includes optical device mechanism parts, parts around light source lamps, sheets or films for metal film laminated substrates, hard disk internal parts, optical fiber connector ferrules, printer parts, copier parts, automobile radiator tank parts, etc. It can be widely used as a foam molded article for automobile engine compartment parts and automobile lamp parts.

  Hereinafter, the present embodiment will be described with specific examples and comparative examples, but the present embodiment is not limited thereto.

The measuring method of the physical property used for the Example and the comparative example is shown below.
(1) Deflection temperature under load (℃)
It measured based on JISK7191-1. The higher the deflection temperature under load, the better the heat resistance.

(2) Notched Charpy impact strength (kJ / m ² )
It measured based on JISK7111-1. The larger the notched Charpy impact strength, the better the impact resistance.

(3) Flame retardancy In accordance with UL94 (standard established by Under Writers Laboratories Inc., USA), a test piece having a length of 125 mm, a width of 13.0 mm, and a thickness of 1.0 mm was prepared using the obtained sheet, and a vertical combustion test was performed. Went.

(4) Specific gravity Measured according to JIS K7112 A method. It was evaluated that the smaller the specific gravity, the better the foamability.

The raw materials used in the examples and comparative examples are shown below.
<(A) Component: Polyphenylene ether resin>
(A1): PPE having a reduced viscosity of 0.51 (dL / g) obtained by oxidative polymerization of 2,6-xylenol.
<(B) Component: Polystyrene resin>
(B1): Natural rubber impact-resistant polystyrene resin (NRGS rubber 50% manufactured by IRPC, rubber cis ratio 99.9%).
(B2): Natural rubber impact-resistant polystyrene resin (IRGS NRGS rubber 30%, rubber cis ratio 99.9%).
(B3): Polybutadiene rubber impact-resistant polystyrene resin (butadiene rubber 10%, rubber cis ratio 96.0%, MFR 5 g / 10 min impact-resistant polystyrene resin was synthesized).
(B4): Homopolystyrene (PS Japan, polystyrene 680).
<(C) Component: Phosphate ester compound>
(C1) Aromatic condensed phosphate ester (CR-741: manufactured by Daihachi Chemical Industry Co., Ltd.).

[Examples 1 to 12, Comparative Examples 1 to 3]
The resin composition was produced using a twin screw extruder ZSK-40 (manufactured by WERNER & PFLIDEERER). In this twin-screw extruder, a first raw material supply port is provided on the upstream side with respect to the flow direction of the raw material, and a first vacuum vent, a second raw material supply port, and a third raw material supply port are provided downstream from this, A second vacuum vent was provided downstream thereof.
In addition, the supply of raw materials to the second and third raw material supply ports is performed using a forced side feeder from the extruder side opening for solid raw materials, and a gear pump from the upper opening of the extruder for liquid raw materials. It was.
Using the extruder set as described above, (a) polyphenylene ether-based resin, (b) polystyrene-based resin, and (c) phosphate ester-based compound were blended in the compositions shown in Tables 1 and 2 below, and the extrusion temperature Melting and kneading were performed under the conditions of 240 to 310 ° C., screw rotation speed of 300 rpm, and discharge rate of 100 kg / hour to produce resin composition pellets corresponding to each example. In addition, since the extruder provided with the deaeration port was used at the time of manufacture of the pellet of a resin composition, the pellet was not foamed.
In addition, the mass part in Tables 1-2 is a value with respect to a total of 100 mass parts of (a) component and (b) component.

Furthermore, using pellets of resin compositions obtained in Examples and Comparative Examples, the pellets were supplied to a screw in-line type injection molding machine set at 200 to 280 ° C., and JIS K7152-1 and a mold temperature of 60 ° C. In accordance with K7313-2, a JIS K7139 test piece was manufactured, and a Charpy impact strength measurement test piece and a load deflection temperature measurement test piece were obtained. Since gas escapes during injection molding, the test piece is not foamed at this time.
Using the obtained test piece, (1) deflection temperature under load and (2) Charpy impact strength were measured. The results are shown in Tables 1-2.

Moreover, the sheet | seat was manufactured as follows using the pellet of the resin composition obtained by the Example and the comparative example. For the production of the sheet, a single screw extruder having a screw diameter of 65 mm set at a cylinder temperature (240 to 300 ° C.) was used. Similarly to the case of the twin screw extruder in the production of the resin composition, nitrogen gas was supplied to the raw material supply line of the single screw extruder, and the oxygen concentration at the raw material supply port was controlled to be less than 1.0% by volume. As detailed manufacturing conditions, the discharge rate was 60 kg / Hr, the thickness of the T-die slit was 1.0 to 1.3 mm, the width of the die slit was 650 mm, and the surface temperature of the rolling roll was 60 to 100 ° C. Under the production conditions, the take-up speed was adjusted to produce a 1.0 mm thick sheet (foamed molded product). Since a twin screw extruder without a deaeration port was used, the obtained sheet was foamed.
About the obtained sheet | seat, each evaluation of (3) flame retardance and (4) specific gravity was performed. The results are shown in Tables 1-2.

  As shown to Tables 1-2, it turned out that the resin composition of Examples 1-12 is excellent in foamability and heat resistance, and also excellent in balance with a flame retardance. Comparative Examples 1 to 3 resulted in a poor balance of foamability, heat resistance and flame retardancy as compared to the Examples. Compared to Example 2, in Comparative Example 2 in which the content of the component (a) was reduced and the content of the component (b) was increased, the deflection temperature under load was low, and the Charpy impact strength was reduced. However, the balance of physical properties was inferior.

  The resin composition of the present invention includes a compact disc / read only memory (CD-ROM), a digital versatile disc / read only memory (DVD-ROM), a compact disc / recordable (CD-R), and a digital versatile disc / recordable. -R Standard (DVD-R), Digital Versatile Disc Recordable + R Standard (DVD + R), Compact Disc Rewritable (CD-RW), Digital Versatile Disc Rewritable -R Standard (DVD-RW), Digital Versatile Optical equipment mechanisms such as discs, rewritables, + R standard (DVD + RW), digital versatile discs, random access memory (DVD-RAM) chassis and cabinet, optical pickup slide base, etc. , Parts around the light source lamp, sheet or film for metal film laminated substrate, hard disk internal parts, laser beam printer internal parts (toner cartridge, etc.), inkjet printer internal parts, copier internal parts, automobile engine room internal parts, electric circuit board, etc. It has industrial applicability.

Claims (4)

(A) 10-70 mass parts of (a) component and 30-90 mass parts of (b) component are included with respect to the total (100 mass parts) of polyphenylene ether resin and (b) polystyrene resin,
A resin composition, wherein a rubber having a cis ratio exceeding 96.0% is dispersed.   The resin composition according to claim 1, wherein the cis ratio of the rubber is 96.4% or more. And (c) a phosphate ester compound,
The resin composition of Claim 1 or 2 containing 7-35 mass parts of (c) component with respect to the sum total (100 mass parts) of (a) component and (b) component.   A foam molded article comprising the resin composition according to any one of claims 1 to 3.