JPH09208791A - Thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a thermoplastic resin having excellent balance among surface hardness, appearance of forming, pigment coloring properties and heat stability, and excellent in chemical resistance against various chemicals and good in weathering resistance and bending elasticity. SOLUTION: This thermoplastic resin composition is obtained by compounding (A) a graft copolymer obtained by subjecting a composite rubber consisting of a polyorganosiloxane and an alkyl (meth)acrylate rubber to graft polymerization with at least one kind of monomer selected from a group consisting of an aromatic alkenyl compound, a methacrylate, an acrylate and a vinyl cyanide compound with (B) a copolymer having the constituting components consisting of at least acrylonitrile and styrene, and containing an acrylonitrile component in an amount of 33-45wt.% in this copolymer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an impact resistant resin having excellent chemical resistance, flexural modulus, impact resistance, thermal stability, weather resistance and pigment coloring property.

[0002]

2. Description of the Related Art Improving the impact resistance of resin materials not only expands the applications of the materials, but also makes it possible to cope with thinner and larger molded products, which is of great industrial utility. The invention is large and has been invented by various methods.

Particularly, a resin material in which a rubber component having a low glass transition temperature (Tg) and a low elastic modulus is dispersed in a resin matrix has been industrialized because of its excellent impact resistance.

Further, such a resin material having excellent impact resistance is used under particularly severe conditions as a metal substitute component in the fields of home electric appliances and vehicles due to its excellent characteristics, and at that time, it is exposed to various chemicals and solvents. Tolerance to these may be necessary because they are often treated. For example, when it is used as an automobile part, it is exposed to mechanical oil or wax remover, and when it is used as a handle or a door cap of a refrigerator, it is exposed to Freon, which is a urethane foaming agent, during the production of a heat insulating material for a refrigerator. In such a usage environment, the resin material often cracks or fine cracks may occur on the surface, and this phenomenon is called environmental stress cracking.
This is a phenomenon that occurs when the molding strain remaining inside the product is partially released by contact with a chemical. Also,
When resin material is used without surface coating such as painting, discoloration or deterioration of luster on the material surface due to light and rainfall becomes a problem, and materials with improved weather resistance are suppressed as much as possible Its industrial value is extremely high because it does not require treatment.

In order to improve the impact resistance of conventional SAN (styrene-acrylonitrile) resins, polyorganosiloxane having a lower Tg and a lower elastic modulus is used as a rubber component, and a vinyl monomer is graft-polymerized to the graft copolymerization. Dispersing the coalesced in a SAN matrix is proposed in JP-A-60-252613.

However, according to this method, a matte appearance defect of molding derived from polyorganosiloxane occurs, and when the appearance of molding is improved by reducing the particle size of the graft copolymer, the impact resistance decreases. Since it is not possible to achieve both high impact resistance and good molding appearance, it has low industrial value.

In JP-A-1-190746, a vinyl monomer is graft-polymerized on a composite rubber composed of 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 resin has been proposed.

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

Further, JP-A-62-280210 discloses a graft copolymer composed of a core of crosslinked silicone, a first shell of crosslinked acrylate rubber, and a second shell of vinyl polymer component. A method of blending the coalescence with a SAN resin has been proposed. Further, in JP-A-64-6012, a graft copolymer obtained by graft-polymerizing an ethylenically unsaturated monomer onto a rubber composed of a core such as a crosslinked acrylate rubber and a shell of polyorganosiloxane is SAN-based resin. The method of blending with is proposed.

Further, the above-mentioned materials requiring chemical resistance are also required to have excellent flexural modulus.

[0011]

However, in the conventional method of blending a SAN-based resin with a graft copolymer containing a polyorganosiloxane for the main purpose of improving impact resistance, any resin composition obtained can be obtained. There is no description about the chemical resistance and elastic modulus of the above and a specific method for improving the same, and SA used in the resin composition shown in each example.
The content of acrylonitrile component in N resin is 25
Only 30% by weight is disclosed, and such SA
A resin composition using an N-based resin has insufficient chemical resistance, weather resistance and elastic modulus, and is suitable for applications requiring particularly high chemical resistance, weather resistance and elastic modulus in the fields of home appliances and vehicles. Cannot be used.

That is, hitherto, in a resin composition composed of a SAN-based resin and a graft copolymer composed of a polyorganosiloxane component, a poly (meth) acrylate component and a graft component, impact resistance, chemical resistance and elastic modulus are obtained. , No material excellent in weather resistance and pigment coloring has been found,
There has been a strong demand for development of a resin material that satisfies these requirements at the same time.

[0013]

SUMMARY OF THE INVENTION The inventors of the present invention have used a matrix SA for a resin composition composed of a SAN-based resin and a graft copolymer containing a composite rubber composed of a polyorganosiloxane and an alkyl (meth) acrylate rubber.
As a result of diligent studies on the amount of acrylonitrile component 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 amount of acrylonitrile as a matrix resin, The present invention has been accomplished by finding that they exhibit 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, methacrylic acid esters, acrylic acid esters and vinyl cyanide compounds is grafted onto a composite rubber composed of a polyorganosiloxane and an alkyl (meth) acrylate rubber. A graft copolymer (A) polymerized with at least acrylonitrile and styrene as constituent components, wherein the copolymer contains 33% by weight to 45% by weight of an acrylonitrile component. ) In the thermoplastic resin composition.

[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 preferable. More preferably, the vinyl polymerizable functional group-containing siloxane unit is 0.3 to
3 mol% and dimethylsiloxane units 97-99.7
The content of the silicon atom is 3 mol% or more, and the silicon atom having 3 or more siloxane bonds is 1 mol% or less with respect to all the silicon atoms in the polydimethylsiloxane. The vinyl-polymerizable functional group-containing siloxane unit in the polyorganosiloxane is 0.3.
If it is less than mol%, the compounding with the alkyl (meth) acrylate rubber will be insufficient, resulting in poor appearance due to bleed-out of polyorganosiloxane on the surface of the resin composition molded article containing the graft copolymer. Cheap. Further, when the vinyl-polymerizable functional group-containing siloxane unit in the polyorganosiloxane exceeds 3 mol% or the silicon atom having three or more siloxane bonds exceeds 1 mol% with respect to all the silicon atoms in the polyorganosiloxane. Impact resistance of the resin composition containing the graft copolymer tends to be low.

Further, considering both impact resistance and molding appearance of the resin composition containing the graft copolymer, preferably 0.5 to 2 mol% of the vinyl polymerizable functional group-containing siloxane unit in the polyorganosiloxane is further contained. Preferably 0.
5 to 1 mol%.

The amount of polyorganosiloxane in the composite rubber according to the present invention is preferably 1 to 20% by weight.
If it 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 impact resistance and pigment colorability 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.

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

The size of the polyorganosiloxane particles is not particularly limited, but considering the pigment colorability of the resin composition containing the graft copolymer, the weight average particle size is 0.2 μm.
m or less, and more preferably 0.1 μm or less.

As the dimethylsiloxane used for producing the polyorganosiloxane, there can be mentioned a dimethylsiloxane cyclic compound having a 3-membered ring or more, and a 3-membered to 6-membered ring is preferable. Specific examples thereof include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, etc. These may be used alone or in combination of two or more.

The vinyl-polymerizable functional group-containing siloxane has a vinyl-polymerizable functional group and can be bonded to dimethyl siloxane through a siloxane bond. Considering the reactivity with dimethyl siloxane, vinyl polymerization is possible. Various alkoxysilane compounds containing a functional group are preferred. Specifically, β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethylsilane, γ−
Methacryloyloxypropyldiethoxymethylsilane and δ-methacryloyloxybutyldiethoxymethylsilane and other methacryloyloxysiloxanes, tetramethyltetravinylcyclotetrasiloxane and other vinylsiloxanes, p-vinylphenyldimethoxymethylsilane and γ-mercaptopropyldimethoxymethylsilane. , Γ-mercaptopropyltrimethoxysilane and other mercaptosiloxanes.

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

As the siloxane-based crosslinking agent, a trifunctional or tetrafunctional silane-based crosslinking agent such as trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, etc. is used.

The emulsifier used in the production of the polyorganosiloxane according to the present invention is preferably an anionic emulsifier, and is selected from sodium alkylbenzenesulfonate, sodium polyoxyethylenenonylphenyl 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. When the amount used is small, the dispersion state becomes unstable, and it becomes impossible to maintain the emulsified state with a fine particle size. Further, if the amount used is large, the coloring of the resin composition molded product due to the emulsifier becomes extremely large, which is inconvenient.

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

Examples of the acid catalyst used for the polymerization of polyorganosiloxane include sulfonic acids such as aliphatic sulfonic acid, aliphatic substituted benzenesulfonic acid and aliphatic substituted naphthalenesulfonic acid, 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, and n-dodecylbenzenesulfonic acid is particularly preferable, because it is also excellent in stabilizing the polyorganosiloxane latex. Also, n-
The combined use of dodecylbenzene sulfonic acid and a mineral acid such as sulfuric acid can reduce the coloring of the resin composition due to the emulsifier component of the polyorganosiloxane latex.

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

The polymerization time of the polyorganosiloxane is 2 hours or more, more preferably 5 hours or more when the acid catalyst is mixed with the siloxane mixture, the emulsifier and water to be finely divided and polymerized. In the method of reducing the latex in which the siloxane mixture is made into fine particles, it is preferable to hold the latex for about 1 hour after the completion of the dropping of the latex.

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

Examples of polyfunctional alkyl (meth) acrylates 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. The alkyl (meth) acrylate and the polyfunctional alkyl (meth) acrylate may be 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 allowing a usual radical polymerization initiator to act. As a method of adding the alkyl (meth) acrylate, there are a method of mixing with the latex of the polyorganosiloxane component at once and a method of dropping it into the latex of the polyorganosiloxane component at a constant rate. Considering the impact resistance of the resulting resin composition containing the graft copolymer, a method of mixing the latex of the polyorganosiloxane component at once is preferable. As the radical polymerization initiator used for polymerization, a peroxide, an azo-based initiator, or a redox-based initiator in which an oxidizing agent and a reducing agent are combined is used. Among these, a redox type initiator is preferable, and a sulfoxylate type initiator in which ferrous sulfate / ethylenediaminetetraacetic acid is combined with sodium salt / Rongalite / hydroperoxide is particularly preferable.

At least one monomer selected from the group consisting of aromatic alkenyl compounds, methacrylic acid esters, acrylic acid esters and vinyl cyanide compounds was graft-polymerized in the graft copolymer (A) according to the present invention. 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 amount of rubber tends to be low, and the impact resistance tends to be low.

The aromatic alkenyl compound is, for example, styrene, α-methylstyrene, vinyltoluene, etc., and the methacrylic acid ester is, for example, methyl methacrylate, ethyl methacrylate, 2-ethylhexyl methacrylate and the like. Examples of the acrylic acid ester include methyl acrylate, ethyl acrylate and butyl acrylate, and examples of the vinyl cyanide compound include acrylonitrile and methacrylonitrile. Of these, a mixture of styrene and acrylonitrile is preferable in view of compatibility with the SAN resin matrix.

In the graft polymerization, at least one monomer selected from the group consisting of an aromatic alkenyl compound, a methacrylic acid ester, an acrylic acid ester and a vinyl cyanide compound is added to a latex of a composite rubber, and a step is further carried out by a radical polymerization technique. Although it can be carried out in multiple steps or in multiple steps, it is preferable to carry out the polymerization in two or more steps in consideration of impact resistance and pigment coloring of the resulting resin composition containing the graft copolymer.

Further, various chain transfer agents for adjusting the molecular weight and 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 resin composition containing the obtained graft copolymer are Considering that, the number average particle diameter is 0.10 to 0.5
μm is preferable, and 0.10 is more preferable.
~ 0.30 μm, more preferably 0.10 to 0.15
μm.

After the graft polymerization is completed, the latex may be poured into hot water in which a metal salt such as calcium chloride or aluminum sulfate is dissolved, salted out and coagulated to separate and recover the graft copolymer. it can.

The copolymer (B) according to the present invention is a copolymer containing at least acrylonitrile and styrene as constituent components, and the acrylonitrile component is contained in the copolymer at 33%.
% To 45% by weight. If the amount of the acrylonitrile component is less than 33% by weight, the chemical resistance and elastic modulus of the resulting resin composition will be poor, and the amount will be 45% by weight.
If it exceeds the above range, the thermal stability of the resulting resin composition becomes poor and a defective molding appearance occurs, so that the industrial value is low.
Considering both the chemical resistance and thermal stability of the resin composition, the preferred amount of acrylonitrile component in the copolymer (B) is 3
It is 5 to 42% by weight, and more preferably 35 to 40% by weight.

[0038] Acrylonitrile and a monomer copolymerizable with styrene, which is optionally used, are used.
For example, unsaturated cyanide compounds such as methacrylonitrile, fumaronitrile and maleonitrile, α-methylstyrene, vinyltoluene, 2,4-dimethylstyrene, p-
Aromatic alkenyl compounds such as bromostyrene and p-chlorostyrene, methacrylic acid esters such as methyl methacrylate, ethyl methacrylate, butyl methacrylate and 2-hydroxyethyl methacrylate, methyl acrylate,
Examples thereof include acrylic acid esters 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) include 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 copolymer (B) according to the present invention can be produced by a generally known emulsion polymerization method, suspension polymerization method, solution polymerization method or bulk polymerization method. Considering the thermal stability and productivity of the obtained copolymer, it is preferable to use the bulk polymerization method for production.

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

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

The resin composition according to the present invention can be produced by extrusion-molding the graft copolymer (A) and the copolymer (B) produced as described above by a commonly 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, a dye, a pigment, a stabilizer, a reinforcing agent, a filler, a flame retardant and the like can be added to the resin composition containing the graft copolymer, if necessary.

[0045]

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

The weight average particle size of the polyorganosiloxane in the latex and the weight average particle size of the graft copolymer in the latex in Reference Examples are the dynamic light scattering using DLS-700 manufactured by Otsuka Electronics Co., Ltd. Obtained by law.

The Izod impact strength in the examples and comparative examples was measured by the method according to ASTM D258.

The surface hardness (Rockwell hardness) in the examples and comparative examples was measured by the method according to ASTM D785.

The flexural modulus in the examples and comparative examples was measured by the method according to ASTM D790.

The evaluation of chemical resistance in Examples and Comparative Examples was carried out by the following procedure. A molded plate having a thickness of 2 mm was produced by a press molding method using the pellets of the resin composition extruded. From this, a 35x120 mm test piece was cut out, and the long diameter was 120 mm and the short diameter was 40 mm.
Attach to the elliptical jig. After the chemical was applied to the surface of the test piece, it was covered with a polyethylene film and exposed to the chemical at 23 ° C. for 4 hours. After exposure, observe the surface condition of the test piece,
The maximum stress-strain value without cracks was used as an index of chemical resistance. That is, it was judged that a material having a larger critical strain value regarding the occurrence of cracks has better chemical resistance. The following chemicals were used in the chemical resistance test.

Dioctyl phthalate Salad oil (manufactured by Nisshin Oil Co., Ltd.) Synthetic household detergent (Magiclin / Kao Corporation) Wax remover (ST-7 / manufactured by Yushiro Kagaku) Injection molding machine IS manufactured by Toshiba Machine Co., Ltd.
100mm x 100mm molded using -100EN
It was evaluated by a hue measurement according to JIS Z8729 using a 3 mm black colored plate. The appearance of the molding was evaluated by visually observing the presence or absence of molding burn and silver generation on the surface of a 100 mm × 100 mm × 3 mm white colored plate, which was molded using an injection molding machine IS-100EN manufactured by Toshiba Machine Co., Ltd. Further, the weather resistance of the resin compositions in Examples and Comparative Examples is 100 mm × 100 mm × 3 mm white colored plate with a sunshine weather meter (manufactured by Suga Test Instruments Co., Ltd.).
It was evaluated by the retention of glossiness after 1000 hours of treatment and the degree of color change (ΔE) measured by a color difference meter.

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, 300 parts of distilled water in which 0.67 part of sodium dodecylbenzenesulfonate was dissolved was added, and the mixture was mixed with a homomixer to obtain 10 parts.
After stirring at 000 rpm for 2 minutes, the homogenizer was passed 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 tube, a jacket heater and a stirring device, and
A 0% dodecylbenzenesulfonic acid aqueous solution was prepared.

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

The latex thus obtained was
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-lauroylsarcosine sodium were collected in a reactor equipped with a reagent injection container, a cooling tube, a jacket heater and a stirrer. , Distilled water 25
After adding and mixing 8.5 parts, butyl acrylate 57
Part, 0.3 part allyl methacrylate, 0.1 part 1,3-butylene glycol dimethacrylate and 0.14 part cumene hydroperoxide.

By passing a nitrogen stream through this reactor, the atmosphere was replaced with nitrogen, and the temperature was raised to 60.degree. When the internal liquid temperature reaches 60 ° C., ferrous sulfate 0.00
01 parts, ethylenediaminetetraacetic acid disodium salt 0.0
An aqueous solution obtained by dissolving 003 parts and 0.24 parts of Rongalit in 10 parts of distilled water was added to start radical polymerization. The liquid temperature rose to 78 ° C. due to the polymerization of the acrylate component. This state was maintained for 1 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 liquid temperature inside the reactor dropped to 60 ° C.,
An aqueous solution prepared by dissolving 0.4 parts of Rongalite in 10 parts of distilled water was added, and then 12.9 parts of acrylonitrile, 38.8 parts of styrene and 0.1 parts of cumene hydroperoxide.
23 parts of the mixed solution was added dropwise over 2 hours for polymerization. After the dropping, the temperature of 60 ° C. was maintained for 1 hour, and then 0.0002 parts of ferrous sulfate, 0.0006 parts of ethylenediaminetetraacetic acid disodium salt and 0.23 parts of Rongalit were dissolved in 10 parts of distilled water. An aqueous solution was added, and then a mixed solution of 7.4 parts of acrylonitrile, 22.2 parts of styrene, and 0.13 part of cumene hydroperoxide was added dropwise over 2 hours for polymerization. After dropping, the temperature is 60 ℃
After maintaining the state of 1 hour for 1 hour, it is cooled to a composite rubber composed of polyorganosiloxane and butyl acrylate rubber,
A latex of a graft copolymer obtained by graft-polymerizing 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.

Then, 150 parts of an aqueous solution in which aluminum sulfate was dissolved in a ratio 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 Example) In Examples and Comparative Examples, the following three kinds of SAN resins were used.

SAN-1: acrylonitrile component 35
%, The styrene component is 65%, and the reduced viscosity (ηsp / C) measured at 25 ° C. in dimethylformamide is 0.7.
SAN resin of 1 dl / g SAN-2: SAN resin consisting of 40% acrylonitrile component and 60% styrene component and having a reduced viscosity (ηsp / C) of 0.75 dl / g measured at 25 ° C. in dimethylformamide. 3: SAN resin comprising 29% acrylonitrile component and 71% styrene component and having a reduced viscosity (ηsp / C) of 0.73 dl / g measured in dimethylformamide at 25 ° C. SAN-4: 48% acrylonitrile component, styrene component SAN resin consisting of 52% and having a reduced viscosity (ηsp / C) of 0.69 dl / g measured at 25 ° C. in dimethylformamide and the graft copolymer prepared in Reference Example and the above SAN.
Resins were mixed at the ratios shown in Table 1, and 0.3% of ADEKA STABLE C (manufactured by Asahi Denka Co., Ltd.) was further used as a heat stabilizer.
Parts, 0.4 parts of barium stearate as a release agent, 0.4 parts of EBS as a lubricant, and carbon black (CB-960: manufactured by Mitsubishi Chemical Corporation) as a coloring agent.
After adding 8 parts, they were thoroughly mixed using a Henschel mixer. The mixture was shaped by a twin-screw extruder set to a barrel temperature of 230 ° C. to prepare pellets. The obtained pellets were molded into a test piece by an injection molding machine in which the cylinder temperature was 230 ° C and the mold temperature was 60 ° C. This test piece was used to evaluate Izod impact strength, Rockwell hardness and pigment colorability. In addition, the colorant of the above resin composition was replaced with titanium oxide (CR60-
2: Ishihara Sangyo Co., Ltd.) was added in an amount of 3.0 parts, 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, the molding appearance and weather resistance were evaluated.

A chemical resistance test was conducted using a test piece prepared by press molding.

The results are shown in Table 1.

[0065]

[Table 1]

From the examples and comparative examples, the following has been clarified.

1) The resin compositions of Examples 1 and 2 and Comparative Example 1 all show high Izod impact strength and surface hardness, and at the same time, show excellent molding appearance and pigment colorability by injection molding.

2) Since the resin compositions of Examples 1 and 2 have the acrylonitrile component as the constituent component of the SAN resin in the range of 33 to 45%, the critical strain of crack generation in the chemical resistance test using each chemical Value is 1.0%
Since it is not (weight) or more, it can be used without any restrictions in use even in an environment exposed to such chemicals, and exhibits an excellent flexural modulus. 3) Since the resin compositions of Examples 1 and 2 have the acrylonitrile component as a constituent component of the SAN resin in the range of 33 to 45%, the molded plate after the weather resistance test using the white colored molded plate has a high gloss. Degree retention and low ΔE,
It can also be used without particular restrictions in applications where it is exposed to light and rainfall.

4) Since the resin composition of Comparative Example 1 contains SAN resin having an acrylonitrile content of less than 33% as a constituent, the critical strain value for crack generation in the chemical resistance test using each chemical is 1.0. % (Not weight)
If the strain is relatively small, cracks will occur. Such a resin material cannot be used in an environment exposed to chemicals, or only in a state where the strain applied to the resin material is reduced as much as possible (for example, the annealing of molded products, the change of part design, etc.). It cannot be used and has a low elastic modulus, and when it is intended to be used for various purposes, its industrial value is low because many restrictions are imposed on its usage conditions. Further, this resin composition has a large ΔE on the surface of the plate after the weather resistance test, and particularly in applications where it is exposed to light and rainfall, it has a low industrial value because use conditions must be restricted. 5) Since the resin composition of Comparative Example 2 contains SAN resin whose acrylonitrile component exceeds 45% as a constituent component, it has poor thermal stability and has a burnt or silver appearance on the surface of the injection molded plate. Defects occurred, and it was not possible to obtain test pieces for the Izod impact test, Rockwell hardness, pigment coloring, chemical resistance test and weather resistance test. In addition, such a resin material having poor thermal stability impairs the design of the molded product and has a low industrial value.

[0070]

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

1) The resin composition according to the present invention has an excellent balance of impact resistance, surface hardness, molding appearance, pigment colorability, and thermal stability, as well as excellent chemical resistance to various chemicals, weather resistance and Has a flexural modulus.

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Yanagase 20-1 Miyuki-cho, Otake-shi, Hiroshima Mitsubishi Rayon Co., Ltd.

Claims (1)

[Claims] 1. A composite rubber comprising a polyorganosiloxane and an alkyl (meth) acrylate rubber, and at least one selected from the group consisting of aromatic alkenyl compounds, methacrylic acid esters, acrylic acid esters and vinyl cyanide compounds. A graft copolymer (A) in which a monomer is graft-polymerized, and a copolymer comprising acrylonitrile and styrene as constituent components of the copolymer, wherein the acrylonitrile component is contained in an amount of 33% by weight to 45% by weight.
A thermoplastic resin composition comprising a copolymer (B) contained in a weight percentage.