JP3218195B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact resistant resin excellent in chemical resistance, flexural modulus, impact resistance, thermal stability, weather resistance and pigment coloring.

[0002]

2. Description of the Related Art Improving the impact resistance of a resin material is extremely useful in industrial applications, such as not only expanding the application of the material but also making it possible to cope with a thinner and larger molded product. The invention has been largely made by various methods.

[0003] In particular, resin materials in which a rubber component having a low glass transition temperature (Tg) and a low elastic modulus are dispersed in a resin matrix have been industrialized due to their excellent impact resistance.

[0004] Further, resin materials having such excellent impact resistance are used under particularly severe conditions as metal replacement parts in the field of home electric appliances and vehicles due to their excellent properties, and are exposed to various chemicals and solvents. Often need to be tolerated. For example, when it is used as an automobile part, it comes into contact with machine oil or wax remover, and when it is used for a handle or door cap of a refrigerator, it is exposed to chlorofluorocarbon which is a urethane foaming agent at the time of manufacturing a heat insulating material for the refrigerator. In such use environment, the resin material often cracks or fine cracks may occur on the surface, this phenomenon is called crack under environmental stress,
This is a phenomenon that occurs when the molding strain remaining inside the product is partially released by contact with the chemical. Also,
If a resin material is used without surface coating such as painting, discoloration or gloss reduction of the material surface due to light or rainfall becomes a problem. Since no treatment is required, the industrial value is extremely high.

Conventionally, in order to improve the impact resistance of a SAN (styrene-acrylonitrile) resin, a polyorganosiloxane having a lower Tg and a lower elastic modulus is used as a rubber component, and a graft copolymer obtained by graft-polymerizing a vinyl monomer with the polyorganosiloxane is used. It has been proposed in JP-A-60-252613 to disperse the coalescence in a SAN matrix.

[0006] However, in this method, a mat-like molded appearance defect derived from polyorganosiloxane occurs, and when the molded article appearance is improved by reducing the particle size of the graft copolymer, impact resistance is reduced. Since high impact resistance and good molded appearance cannot be compatible, the industrial value is low.

JP-A-1-190746 discloses that a vinyl monomer is graft-polymerized on a composite rubber comprising a polyorganosiloxane rubber and a poly (meth) acrylate rubber in order to improve the surface appearance of a resin molded product. A method of blending a graft copolymer with a SAN-based resin has been proposed.

[0008] Japanese Patent Application Laid-Open No. 6-25492 discloses that
As a method for improving the pigment coloring property of the impact resistant resin, a number average particle diameter of a composite rubber composed of polyorganosiloxane and (meth) acrylate obtained by graft polymerization of a vinyl monomer is 0.01 to 0.07 μm. A method has been proposed in which a graft copolymer having particles larger than 0.10 μm and 20% by volume or less is blended with a SAN-based resin.

Japanese Patent Application Laid-Open No. 62-280210 discloses a graft copolymer comprising a core of a crosslinked silicone, a first shell of a crosslinked acrylate rubber, and a second shell made of a vinyl polymer component. A method of blending the coalesced with the SAN-based resin has been proposed. Further, JP-A-64-6012 discloses a SAN-based resin comprising a graft copolymer obtained by graft-polymerizing an ethylenically unsaturated monomer on a rubber comprising a core of a crosslinked acrylate rubber and a polyorganosiloxane shell. Has been proposed.

[0010] In addition, a material that requires chemical resistance as described above also requires an excellent flexural modulus.

[0011]

However, in the conventional method of blending a graft copolymer containing a polyorganosiloxane with a SAN-based resin for the purpose of mainly improving the impact resistance, any of the resin compositions obtained can be obtained. There is no description about the chemical resistance and elastic modulus of the resin and no specific method for improving the same, and the SA used in the resin compositions shown in the respective examples is not described.
The acrylonitrile component content in the N-based resin is 25
Only 30% by weight is disclosed.
A resin composition using an N-based resin does not have sufficient chemical resistance, weather resistance and elastic modulus, and is particularly suitable for applications requiring a high degree of chemical resistance, weather resistance and elastic modulus in the field of home appliances or vehicles. Cannot be used.

That is, conventionally, in a resin composition comprising a SAN-based resin and a graft copolymer comprising a polyorganosiloxane component, a poly (meth) acrylate component and a graft component, and impact resistance, chemical resistance and elastic modulus. , A material excellent in weather resistance and pigment coloring has not been found,
The development of a resin material that satisfies these requirements at the same time has been strongly desired.

[0013]

Means for Solving the Problems The present inventors have developed a resin composition comprising a SAN-based resin and a graft copolymer containing a composite rubber comprising a polyorganosiloxane and an alkyl (meth) acrylate rubber, which is a matrix.
As a result of intensive studies on the acrylonitrile component amount in the N-based resin and the impact resistance and chemical resistance of the resin composition, surprisingly, by using a SAN-based resin having a specific acrylonitrile component amount as a matrix resin, The present invention was found to show excellent chemical resistance, weather resistance and elastic modulus.

That is, the gist of the present invention is as follows.
At least one monomer selected from the group consisting of aromatic alkenyl compounds, methacrylates, acrylates and vinyl cyanide compounds is grafted onto a composite rubber comprising a polyorganosiloxane and an alkyl (meth) acrylate rubber. A copolymer (B) comprising a polymerized graft copolymer (A) and at least acrylonitrile and styrene as constituent components, wherein the copolymer contains 33% by weight to 45% by weight of an acrylonitrile component. )).

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION The polyorganosiloxane constituting the graft copolymer (A) according to the present invention is not particularly limited, but a polyorganosiloxane containing a vinyl polymerizable functional group is preferred. More preferably, the vinyl polymerizable functional group-containing siloxane unit 0.3 to 0.3
3 mol% and 97-99.7 dimethylsiloxane units
Mol%, and silicon atoms having three or more siloxane bonds are 1 mol% or less based on all silicon atoms in the polydimethylsiloxane. When the siloxane unit containing a vinyl polymerizable functional group in the polyorganosiloxane is 0.3
If the amount is less than mol%, the complexation with the alkyl (meth) acrylate rubber becomes insufficient, resulting in poor appearance due to bleed out of the polyorganosiloxane on the surface of the resin composition molded article containing the graft copolymer. Cheap. Further, when the siloxane unit having a vinyl polymerizable functional group in the polyorganosiloxane exceeds 3 mol%, or when the silicon atom having three or more siloxane bonds exceeds 1 mol% with respect to the total silicon atom in the polyorganosiloxane. The impact resistance of the resin composition containing the graft copolymer tends to be low.

In consideration of both impact resistance and molded appearance of the resin composition containing the graft copolymer, preferably, the siloxane unit containing a vinyl polymerizable functional group in the polyorganosiloxane is 0.5 to 2 mol%. Preferably 0.
5 to 1 mol%.

The amount of the polyorganosiloxane in the composite rubber according to the present invention is preferably 1 to 20% by weight.
If the amount is less than 1% by weight, the impact resistance tends to be low because the amount of polyorganosiloxane is small, and if it exceeds 20% by weight, the pigment coloring property of the resin composition molded article containing the graft copolymer tends to decrease. Further, considering both the impact resistance and pigment coloring of the resin composition containing the graft copolymer,
The amount of polyorganosiloxane in the composite rubber is preferably 6 to 20% by weight, more preferably 10 to 20% by weight.

The polyorganosiloxane is prepared by mixing a mixture of dimethylsiloxane and a siloxane having a vinyl polymerizable functional group or, if necessary, a mixture containing a siloxane-based crosslinking agent with a latex obtained by emulsifying the mixture with an emulsifier and water. After homogenizing using a homomixer that atomizes by shearing force due to rotation or a homogenizer that atomizes by jetting power from a high-pressure generator, polymerize at high temperature using an acid catalyst, and then acidify with an alkaline substance. Is to neutralize. Examples of the method of adding the acid catalyst used for the polymerization include a method of mixing with a siloxane mixture, an emulsifier and water, and a method of dropping a latex in which the siloxane mixture is finely divided into a high-temperature acid aqueous solution at a constant rate. Considering the ease of controlling the particle size of the siloxane, a method of dropping a latex in which the siloxane mixture is finely divided into a high-temperature acid aqueous solution at a constant rate is preferable.

Although the size of the polyorganosiloxane particles is not particularly limited, the weight average particle diameter is 0.2 μm in consideration of the pigment coloring property of the resin composition containing the graft copolymer.
m or less, more preferably 0.1 μm or less.

The dimethylsiloxane used in the production of the polyorganosiloxane includes a dimethylsiloxane-based cyclic body having three or more membered rings, preferably a three- to six-membered ring. Specific examples include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, and the like. These may be used alone or as a mixture of two or more.

The siloxane containing a vinyl polymerizable functional group is a siloxane containing a vinyl polymerizable functional group and capable of bonding to dimethyl siloxane through a siloxane bond. Various alkoxysilane compounds containing a functional group are preferred. Specifically, β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, γ-
Methacryloyloxysiloxanes such as methacryloyloxypropyldiethoxymethylsilane and δ-methacryloyloxybutyldiethoxymethylsilane; vinylsiloxanes such as tetramethyltetravinylcyclotetrasiloxane; p-vinylphenyldimethoxymethylsilane; and γ-mercaptopropyldimethoxymethylsilane And mercaptosiloxanes such as γ-mercaptopropyltrimethoxysilane.

These vinyl polymerizable functional group-containing siloxanes can be used alone or as a mixture of two or more.

As the siloxane-based crosslinking agent, a trifunctional or tetrafunctional silane crosslinking agent, for example, trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane and the like are used.

As the emulsifier used in the production of the polyorganosiloxane according to the present invention, an anionic emulsifier is preferable, and an emulsifier selected from sodium alkylbenzenesulfonate, sodium polyoxyethylene nonylphenyl ether sulfate and the like. Is used.
Particularly, sulfonic acid emulsifiers such as sodium alkylbenzene sulfonate and sodium lauryl sulfonate are preferable. These emulsifiers are used in an amount of about 0.05 to 5 parts by weight based on 100 parts by weight of the siloxane mixture. If the amount used is small, the dispersion state becomes unstable and the emulsified state with a fine particle diameter cannot be maintained. On the other hand, if the amount is too large, the resin composition molded article caused by the emulsifier becomes extremely colored, which is inconvenient.

The method of mixing a siloxane mixture, an emulsifier, water and / or an acid catalyst includes mixing by high-speed stirring and mixing by a high-pressure emulsifying device such as a homogenizer. A method using a homogenizer is a method using a polyorganosiloxane. This is a preferred method because the particle size distribution of the latex becomes smaller.

Examples of the acid catalyst used for the polymerization of polyorganosiloxane include sulfonic acids such as aliphatic sulfonic acids, aliphatic substituted benzenesulfonic acids, and aliphatic substituted naphthalenesulfonic acids, and mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid. . These acid catalysts are used alone or in combination of two or more. Among these, aliphatic substituted benzenesulfonic acid is preferable because of excellent stabilizing action of the polyorganosiloxane latex, and n-dodecylbenzenesulfonic acid is particularly preferable. Also, n-
When dodecylbenzenesulfonic acid and a mineral acid such as sulfuric acid are used in combination, coloring of the resin composition due to the emulsifier component of the polyorganosiloxane latex can be reduced.

The polymerization temperature of the polyorganosiloxane is 5
The temperature is preferably 0 ° C or more, more preferably 80 ° C or more.

The polymerization time of the polyorganosiloxane is 2 hours or more, more preferably 5 hours or more, when the acid catalyst is mixed with a siloxane mixture, an emulsifier and water to form fine particles and polymerized. In the method of lowering the latex in which the siloxane mixture has been made finer, it is preferable to hold the latex for about 1 hour after the completion of dropping of the latex.

The termination of the polymerization can be carried out by cooling the reaction solution and neutralizing the latex with an alkaline substance such as caustic soda, caustic potash and sodium carbonate. The alkyl (meth) acrylate rubber constituting the graft copolymer (A) according to the present invention is an alkyl (meth)
The composite rubber is a polymer of acrylate and polyfunctional alkyl (meth) acrylate, and the composite rubber is made of polyorganosiloxane latex containing alkyl (meth) acrylate and polyfunctional alkyl (meth) acrylate. It can be produced by impregnating the (meth) acrylate component followed by polymerization. Examples of the alkyl (meth) acrylate include alkyl acrylates such as methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate and 2-ethylhexyl acrylate, and hexyl methacrylate. Rate,
Examples thereof include alkyl methacrylates such as 2-ethylhexyl methacrylate and n-lauryl methacrylate, and use of n-butyl acrylate is particularly preferable.

Examples of the polyfunctional alkyl (meth) acrylate include allyl methacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, and 1,3-butylene glycol dimethacrylate.
And 1,4-butylene glycol dimethacrylate, triallyl cyanurate, triallyl isocyanurate and the like. The amount of the polyfunctional alkyl (meth) acrylate used is 0.1 to 20% by weight, preferably 0.2 to 5% by weight in the alkyl (meth) acrylate component.
More preferably, it is 0.2 to 1% by weight. Alkyl (meth) acrylates and polyfunctional alkyl (meth) acrylates are used alone or in combination of two or more.

The composite rubber comprising the polyorganosiloxane and the alkyl (meth) acrylate rubber according to the present invention is:
It can be prepared by adding the above-mentioned alkyl (meth) acrylate component to the latex of the polyorganosiloxane component and polymerizing it by the action of a usual radical polymerization initiator. As a method for adding the alkyl (meth) acrylate, there is a method of mixing the poly (organosiloxane) component with the latex of the polyorganosiloxane component at once, or a method of dropping into the latex of the polyorganosiloxane component at a constant speed. In consideration of the impact resistance of the obtained resin composition containing the graft copolymer, a method of mixing the latex of the polyorganosiloxane component at a time is preferable. As the radical polymerization initiator used for the polymerization, a peroxide, an azo initiator, or a redox initiator obtained by combining an oxidizing agent and a reducing agent is used. Among these, a redox initiator is preferable, and a sulfoxylate initiator obtained by combining sodium salt, Rongalit and hydroperoxide with ferrous sulfate / ethylenediaminetetraacetic acid is particularly preferable.

In the graft copolymer (A) according to the present invention, at least one monomer selected from the group consisting of aromatic alkenyl compounds, methacrylates, acrylates and vinyl cyanide compounds is graft-polymerized. The amount of the graft component is not particularly limited, but is preferably 50 to 80% by weight, more preferably 50 to 70% by weight, and further preferably 50 to 60% by weight. If it is less than 50% by weight, the pigment coloring property of the resin composition molded article containing the graft copolymer tends to decrease,
On the other hand, if it exceeds 80% by weight, the impact resistance tends to be low because the amount of rubber is low.

Examples of the aromatic alkenyl compound include styrene, α-methylstyrene, vinyltoluene and the like, and examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate and 2-ethylhexyl methacrylate. Examples of the acrylate include methyl acrylate, ethyl acrylate, and butyl acrylate, and examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. Among them, a mixture of styrene and acrylonitrile is preferable in consideration of compatibility with the SAN-based resin matrix.

In the graft polymerization, at least one monomer selected from the group consisting of an aromatic alkenyl compound, a methacrylate, an acrylate and a vinyl cyanide compound is added to the latex of the composite rubber, and one step is performed by a radical polymerization technique. The polymerization may be carried out in two or more stages in consideration of the impact resistance and pigment coloring of the obtained resin composition containing the graft copolymer.

Further, various chain transfer agents for adjusting the molecular weight and the graft ratio of the graft polymer can be added to the monomers used in the graft polymerization. The particle size of the graft copolymer (A) prepared as described above is not particularly limited, but both the impact resistance and the pigment coloring property of the obtained resin composition containing the graft copolymer are not limited. Considering the number average particle diameter is 0.10 to 0.5
μm, more preferably 0.10 μm.
0.30 μm, more preferably 0.10 to 0.15
μm.

After the completion of the graft polymerization, the latex is poured into hot water in which a metal salt such as calcium chloride or aluminum sulfate is dissolved, salted out and solidified to separate and collect the graft copolymer. it can.

The copolymer (B) according to the present invention is a copolymer comprising at least acrylonitrile and a styrene component, and the copolymer contains 33 parts of an acrylonitrile component.
% By weight to 45% by weight. If the amount of the acrylonitrile component is less than 33% by weight, the resulting resin composition has poor chemical resistance and elastic modulus, and has an amount of 45% by weight.
When the ratio exceeds the above range, the thermal stability of the obtained resin composition becomes poor, and the appearance of the molded product becomes poor, so that the industrial value is low.
Considering both the chemical resistance and the thermal stability of the resin composition, the preferred amount of the acrylonitrile component in the copolymer (B) is 3
It is 5 to 42% by weight, more preferably 35 to 40% by weight.

A monomer copolymerizable with acrylonitrile and styrene used as needed is used.
For example, unsaturated cyanide compounds such as methacrylonitrile, fumaronitrile and maleonitrile, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, p-
Bromostyrene, aromatic alkenyl compounds such as p-chlorostyrene, methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-hydroxyethyl methacrylate, methyl acrylate,
Examples include acrylates such as ethyl acrylate, butyl acrylate, and propyl acrylate; maleimide compounds such as N-phenylmaleimide and N-alkylmaleimide; and unsaturated acid anhydrides such as maleic anhydride.

Preferred examples of the copolymer (B) are an acrylonitrile styrene copolymer containing 33 to 45% by weight of an acrylonitrile component and an acrylonitrile styrene-N-phenylmaleimide containing 33 to 45% by weight of an acrylonitrile component. It is a copolymer.

The production of the copolymer (B) according to the present invention can be carried out by generally known emulsion polymerization, suspension polymerization, solution polymerization and bulk polymerization. In consideration of the thermal stability and productivity of the obtained copolymer, it is preferable to use the bulk polymerization method.

The copolymer (B) according to the present invention can be used alone or as a mixture of two or more copolymers.

The copolymer (B) according to the present invention can be blended in an appropriate amount with the graft copolymer (A).

The resin composition according to the present invention can be produced by extruding the graft copolymer (A) and the copolymer (B) produced as described above by a usual and known kneading machine. it can. Examples of such a molding machine include an extruder, an injection molding machine, a blow molding machine, a calender molding machine and an inflation molding machine.

Further, the resin composition containing the graft copolymer may contain a dye, a pigment, a stabilizer, a reinforcing agent, a filler, a flame retardant, and the like, if necessary.

[0045]

EXAMPLES The present invention will be described below with reference to examples. In addition,
In Reference Examples, Examples and Comparative Examples, "parts" and "%" are "parts by weight" and "% by weight" unless otherwise specified.
Means

The weight-average particle diameter of the polyorganosiloxane in the latex and the weight-average particle diameter of the graft copolymer in the latex in the Reference Example were determined by dynamic light scattering using a DLS-700 manufactured by Otsuka Electronics Co., Ltd. It was determined by the method.

The measurement of the Izod impact strength in the examples and comparative examples was performed by a method according to ASTM D258.

The measurement of the surface hardness (Rockwell hardness) in Examples and Comparative Examples was performed by a method according to ASTM D785.

The measurement of the flexural modulus in the examples and comparative examples was performed by a method based on ASTM D790.

The evaluation of chemical resistance in Examples and Comparative Examples was performed according to the following procedure. Using an extruded resin composition pellet, a molded plate having a thickness of 2 mm was produced by a press molding method. From this, a specimen of 35 × 120 mm was cut out, and 1/4 of the long diameter 120 mm and the short diameter 40 mm.
Attach to the elliptical jig. After the drug was applied to the surface of the specimen, the sample was covered with a polyethylene film and exposed to the drug at 23 ° C. for 4 hours. Observe the surface condition of the specimen after exposure,
The maximum stress-strain value without cracks was used as an index of chemical resistance. That is, it was determined that a material having a larger critical strain value related to the crack generation was more excellent in chemical resistance. The following chemicals were used in the chemical resistance test.

Dioctyl phthalate Salad oil (manufactured by Nisshin Oil Co., Ltd.) Home synthetic detergent (manufactured by Magiclin / Kao Corporation) Wax remover (ST-7 / Yushiro Chemical Co., Ltd.) Injection molding machine IS manufactured by Toshiba Machine Co., Ltd.
100mm x 100mm molded using -100EN
It was evaluated by hue measurement based on JIS Z8729 using a x3 mm black colored plate. The appearance of the molded product was evaluated by visually observing whether or not the surface of the 100 mm × 100 mm × 3 mm white colored plate surface was burnt or silver was formed using an injection molding machine IS-100EN manufactured by Toshiba Machine Co., Ltd. In addition, the weather resistance of the resin compositions in Examples and Comparative Examples was determined by using a 100 mm × 100 mm × 3 mm white colored plate with a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.).
And the degree of discoloration (ΔE) measured by a color difference meter after the treatment for 1000 hours.

Reference Example Production of Graft Copolymer (S-1) 98 parts of octamethylcyclotetrasiloxane and 2 parts of γ-methacryloyloxypropyldimethoxymethylsilane were mixed to obtain 100 parts of a siloxane-based mixture. To this was added 300 parts of distilled water in which 0.67 part of sodium dodecylbenzenesulfonate was dissolved, and 10 parts were added with a homomixer.
After stirring at 2,000 rpm for 2 minutes, the mixture was passed through a homogenizer once at a pressure of 300 kg / cm @ 2 to obtain a stable premixed organosiloxane latex.

On the other hand, 10 parts of dodecylbenzenesulfonic acid and 90 parts of distilled water were injected into a reactor equipped with a reagent injection container, a cooling pipe, a jacket heater and a stirrer.
A 0% dodecylbenzenesulfonic acid aqueous solution was prepared.

While the aqueous solution was heated to 85 ° C., the premixed organosiloxane latex was added dropwise over 4 hours, and after completion of the addition, the temperature was maintained for 1 hour and the system was cooled. The reaction was then neutralized with aqueous caustic soda.

The latex thus obtained was mixed with 17
When the solid content was determined by drying at 0 ° C. for 30 minutes, 17.
7%. The weight average particle diameter of the polyorganosiloxane in the latex was 0.05 μm.

Next, 53.3 parts of the above polyorganosiloxane latex and 0.3 part of N-lauroyl sarcosine sodium were collected in a reactor equipped with a reagent injection container, a cooling pipe, a jacket heater and a stirring device. , Distilled water 25
After adding and mixing 8.5 parts, butyl acrylate 57 was added.
Parts, allyl methacrylate 0.3 part, 1,3-butyleneglycol dimethacrylate 0.1 part and cumene hydroperoxide 0.14 part.

The atmosphere was replaced with nitrogen by passing a nitrogen stream through this reactor, and the temperature was raised to 60 ° C. When the internal liquid temperature reaches 60 ° C., ferrous sulfate 0.00
01 parts, ethylenediaminetetraacetic acid disodium salt 0.0
An aqueous solution in which 003 parts and 0.24 parts of Rongalite were dissolved in 10 parts of distilled water was added to initiate radical polymerization. The liquid temperature rose to 78 ° C. due to the polymerization of the acrylate component. This state was maintained for one hour to complete the polymerization of the acrylate component to obtain a latex of a composite rubber of polyorganosiloxane and butyl acrylate rubber.

After the temperature of the liquid inside the reactor has dropped to 60 ° C.,
An aqueous solution obtained by dissolving 0.4 part of Rongalite in 10 parts of distilled water is added, and then 12.9 parts of acrylonitrile, 38.8 parts of styrene and 0.1 part of cumene hydroperoxide are added.
23 parts of the mixture was added dropwise over 2 hours to carry out polymerization. After completion of the dropwise addition, the temperature of 60 ° C. was maintained for 1 hour, and then 0.0002 parts of ferrous sulfate, 0.0006 parts of disodium ethylenediaminetetraacetate and 0.23 parts of Rongalite were dissolved in 10 parts of distilled water. An aqueous solution was added, and then a mixture of 7.4 parts of acrylonitrile, 22.2 parts of styrene, and 0.13 part of cumene hydroperoxide was dropped and polymerized over 2 hours. After dropping, temperature 60 ° C
After holding for 1 hour, the mixture was cooled to form a composite rubber comprising polyorganosiloxane and butyl acrylate rubber.
A latex of a graft copolymer obtained by graft polymerization of acrylonitrile and styrene was obtained.

The weight average particle diameter of the graft copolymer in the latex determined by the dynamic light scattering method was 0.13 μm.

Next, 150 parts of an aqueous solution in which aluminum sulfate was dissolved at a rate of 7.5% was heated to 60 ° C. and stirred.
100 parts of the latex of the graft copolymer was gradually dropped into this, and solidified. Next, the precipitate was separated, washed and dried to obtain a graft copolymer (S-1).

Examples 1 and 2 and Comparative Examples In Examples and Comparative Examples, the following three types of SAN resins were used.

SAN-1: acrylonitrile component 35
%, A styrene component of 65%, and a reduced viscosity (ηsp / C) of 0.7 in dimethylformamide measured at 25 ° C.
SAN resin of 1 dl / g SAN-2: SAN resin consisting of 40% of acrylonitrile component and 60% of styrene component and having a reduced viscosity (ηsp / C) of 0.75 dl / g measured at 25 ° C. in dimethylformamide. 3: SAN resin having an acrylonitrile component of 29% and a styrene component of 71%, and having a reduced viscosity (ηsp / C) of 0.73 dl / g measured in dimethylformamide at 25 ° C. SAN-4: 48% of an acrylonitrile component and a styrene component SAN resin having a reduced viscosity (ηsp / C) of 0.69 dl / g measured in dimethylformamide at 25 ° C. The graft copolymer produced in Reference Example and the above SAN
The resins were mixed in the proportions shown in Table 1, and 0.3% of Adekastable C (manufactured by Asahi Denka Co., Ltd.) as a heat stabilizer.
Parts, 0.4 parts of barium stearate as a releasing agent, 0.4 parts of EBS as a lubricant, and 0.1 parts of carbon black (CB-960: manufactured by Mitsubishi Chemical Corporation) as a coloring agent.
After adding 8 parts, the mixture was sufficiently mixed using a Henschel mixer. These mixtures were shaped by a twin-screw extruder set at a barrel temperature of 230 ° C. to produce pellets. Test pieces were molded from the obtained pellets using an injection molding machine set at a cylinder temperature of 230 ° C. and a mold temperature of 60 ° C. The Izod impact strength, Rockwell hardness and pigment coloring were evaluated using the test pieces. Further, the coloring agent of the above resin composition is replaced with titanium oxide (CR60-) instead of carbon black.
2: Ishihara Sangyo Co., Ltd.) was added, and the same blending, shaping and injection molding were carried out to obtain 100 mm × 100
A white colored plate of mm × 3 mm was obtained. Using this plate, a molded appearance and weather resistance were evaluated.

Further, a chemical resistance test was performed using a test piece produced by press molding.

Table 1 shows the results.

[0065]

[Table 1]

The following has been made clear from the examples and comparative examples.

1) The resin compositions of Examples 1 and 2 and Comparative Example 1 all exhibit high Izod impact strength and surface hardness, as well as excellent molding appearance and pigment coloring by injection molding.

2) Since the resin compositions of Examples 1 and 2 contain a SAN resin in which the acrylonitrile component is in the range of 33 to 45%, a critical strain of crack generation in a chemical resistance test using each chemical is given. Value is 1.0%
(Not by weight), it can be used in an environment exposed to such chemicals without any particular restrictions on use, and exhibits excellent flexural modulus. 3) Since the resin compositions of Examples 1 and 2 contain a SAN resin having an acrylonitrile component in the range of 33 to 45%, the molded plate after the weather resistance test using a white-colored molded plate has high gloss. Degree of retention and low ΔE,
It can be used in applications exposed to light and rain without any particular restrictions on use.

4) Since the resin composition of Comparative Example 1 contains a SAN resin having an acrylonitrile component of less than 33%, the critical strain value for crack generation in a chemical resistance test using each chemical is 1.0. % (Not weight)
If it is smaller, the crack will occur even with relatively small distortion. Such a resin material cannot be used in an environment exposed to chemicals, or is used only in a state where distortion applied to the resin material is reduced as much as possible (for example, performing annealing of a molded product, changing part design, etc.). It cannot be used and has a low modulus of elasticity, and when it is used for various purposes, the industrial conditions are low because many restrictions are required for use conditions. In addition, this resin composition has a large ΔE on the plate surface after the weather resistance test, and in particular, in applications where it is exposed to light or rain, its use conditions require restrictions, so its industrial value is low. 5) Since the resin composition of Comparative Example 2 contains a SAN resin having an acrylonitrile component in a range of more than 45% as a component, it has poor thermal stability, burns on the surface of an injection molded plate, and has an appearance such as silver. Defectiveness occurred, and test pieces for performing the Izod impact test, Rockwell hardness, pigment coloring, chemical resistance test, and weather resistance test could not be obtained. In addition, such a resin material having poor thermal stability has a low industrial value because the design of a molded article is impaired.

[0070]

As described above, the present invention has the following remarkable effects, and its industrial value is extremely large.

1) The resin composition according to the present invention has excellent balance of impact resistance, surface hardness, molded appearance, pigment coloring property, and thermal stability, and has excellent chemical resistance, weather resistance and resistance to various chemicals. It has a flexural modulus.

2) Particularly, the chemical resistance, the weather resistance and the flexural modulus are extremely high, which cannot be obtained with a resin material using a conventionally known composite rubber composed of polyorganosiloxane and acrylate rubber as a rubber source. Therefore, its value as various industrial materials is extremely high.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-157629 (JP, A) JP-A-1-190746 (JP, A) JP-A-6-25492 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08L 51/00 C08L 25/12 C08L 51/08

Claims (1)

(57) [Claims] 1. A composite rubber comprising a polyorganosiloxane and an alkyl (meth) acrylate rubber, wherein at least one kind selected from the group consisting of an aromatic alkenyl compound, a methacrylate, an acrylate and a vinyl cyanide compound. A copolymer comprising a graft copolymer (A) obtained by graft-polymerizing a monomer and acrylonitrile and styrene as constituents of a copolymer, wherein the acrylonitrile component contains 33% by weight to 45% by weight of the copolymer.
A thermoplastic resin composition comprising the copolymer (B) containing the copolymer by weight.