JP2926367B2 - Graft copolymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a graft copolymer of a polyorganosiloxane composite rubber which can be blended with various resins to give a molded article having excellent impact resistance and surface appearance.

[0002]

2. Description of the Related Art Generally, an impact-resistant resin comprises a rubber phase and a matrix phase, and a rubber phase having a glass transition temperature (hereinafter abbreviated as Tg) as low as possible is used. It is said to be advantageous in absorbing impact energy. Tg is -55 ° C
It has been demonstrated that a resin using a polybutadiene-based rubber having a Tg of -80 ° C., for example, an ABS resin, is superior in impact resistance to an impact-resistant resin using a polybutyl acrylate-based rubber. . From this, it is considered that if polydimethylsiloxane having a Tg of -123 ° C. can be used as a rubber source, an impact-resistant resin superior to ABS will be obtained. However, polyorganosiloxanes have poor reactivity with vinyl monomers and are difficult to form chemical bonds. Therefore, polyorganosiloxanes have sufficient performance even when polyorganosiloxane is used as a rubber source of impact-resistant resin. And it was difficult.

In an attempt to improve the impact resistance by forming a chemical bond between a polyorganosiloxane and a vinyl monomer, US Pat. No. 3,898,300 discloses a polydimethylsiloxane polymer containing vinylsiloxane or allylsiloxane. It is described that a graft copolymer is formed by polymerizing a vinyl monomer in an emulsion of US Pat. No. 4,071,577. It describes that a monomer is grafted, and JP-A-60-252613 describes a graft copolymer using a methacryloyloxy group-containing polyorganosiloxane. These have a certain effect of improving the impact resistance, but are required to have a higher improving effect, and there is a problem that the resin to which this is added is inferior in surface gloss.

In view of such circumstances, as a result of intensive studies, a composite obtained by graft-polymerizing a vinyl monomer with high efficiency to a composite rubber comprising a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component has been obtained. By combining the rubber-based graft copolymer with various thermoplastic resins, a molded article having excellent impact resistance, weather resistance and surface appearance is obtained, and a resin composition having excellent moldability and fluidity is obtained. (Japanese Patent Laid-Open No. 64-79)
257, 64-79255, and JP-A-1-
190746).

However, in these methods, a large amount of a polyalkyl (meth) acrylate rubber must be used in order to improve the compatibility between the polyorganosiloxane component and the thermoplastic resin. However, it is hard to say that it has fully utilized the impact strength-improving ability, and there is a demand for one having even higher impact resistance.

JP-A-64-6012 discloses that butadiene is first polymerized, and then an organosiloxane is polymerized in the presence of polybutadiene to form a polybutadiene core.
An attempt to obtain a rubber having a polyorganosiloxane shell and graft polymerize an ethylenically unsaturated monomer to the rubber is described. But in this way,
Perhaps because the polymerization of the organosiloxane does not proceed smoothly in the presence of polybutadiene, the polyorganosiloxane and polybutadiene cannot take a structure that is entangled so that they cannot be separated from each other, and the gel content of the resulting rubber decreases. There is a problem that even if such a graft copolymer is blended with a resin, the impact resistance does not become sufficiently high.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies in view of such a situation. As a result, polyorganosiloxane rubber is emulsion-polymerized, and when a conjugated diene is polymerized in the presence of the latex, polyorganosiloxane and polyorganosiloxane are mixed. The conjugated diene polymer is entangled with each other to form a structure that cannot be separated, so that a rubber having a high gel content can be obtained.When the swelling degree is controlled to a specific range, when the rubber is compounded with a thermoplastic resin, The impact resistance of the molded product becomes excellent, and the hardness of the resin can be maintained high, the appearance of the molding is improved, and when the particle size of the composite rubber is controlled to a specific range, the impact resistance is more excellent And arrived at the present invention.

That is, the gist of the present invention is that 1 to 99% by weight of a polyorganosiloxane rubber component and 99 to 100% of a conjugated diene rubber component
1% by weight, having a structure in which both components are entangled with each other so that they cannot be separated from each other, and have a gel content of 80% or more measured using a toluene solvent and a swelling degree of 10 to 40. A composite rubber-based graft copolymer obtained by graft-polymerizing one or more vinyl monomers onto a composite rubber.

Instead of the above-described composite rubber, one of a polyorganosiloxane rubber and a conjugated diene rubber or a simple mixture of both is used as a rubber source, and one obtained by grafting one or more vinyl monomers to the rubber source is used. It does not become an excellent impact modifier even if it is used as a rubber source because it uses a composite rubber that is entangled and combined as a rubber source so that the polyorganosiloxane rubber component and the conjugated diene rubber component cannot be separated. And is a compounding component.

When the content of the polyorganosiloxane rubber component in the composite rubber exceeds 99% by weight, the surface appearance of a molded article obtained from a composition obtained by adding a graft copolymer using the composite rubber to a resin tends to deteriorate. On the contrary, if the conjugated diene rubber component exceeds 99% by weight, the effect of improving the impact resistance of the obtained graft copolymer decreases.

The swelling degree of the composite rubber used in the present invention is 10 to 10.
It is required to be 40, and preferably 15 to 30. The degree of swelling is a value obtained by dividing the weight of toluene absorbed by the composite rubber when the composite rubber is immersed in toluene at 23 ° C. for 24 hours by the weight of the composite rubber before immersion. That is, when 1 g of the composite rubber occludes 10 to 40 g of toluene, the degree of swelling of the rubber is 10 to 40. If the degree of swelling of the composite rubber is less than 10, the impact resistance is reduced.
When the degree of swelling exceeds 40, the surface hardness of a molded article formed from a composition obtained by blending the same with a thermoplastic resin is reduced, and the appearance is deteriorated.

The gel content of the composite rubber used in the present invention measured by extraction with toluene at 90 ° C. for 12 hours is 80%.
% By weight or more, and preferably 85% by weight or more. When the gel content is less than 80% by weight, the effect of improving the impact resistance is also slightly lowered at the same time as the surface hardness is lowered.

The composite rubber has an average particle diameter of 0.18 μm.
The impact resistance of the resin composition containing the obtained graft copolymer tends to decrease when it is less than 0.4, and the impact resistance of the resin composition containing the graft copolymer decreases when it exceeds 0.4 μm. Since the surface appearance of the molded product tends to deteriorate, the average particle size is 0.18 to 0.4.
It is preferably in the range of μm. Emulsion polymerization is the most suitable method for producing composite rubber having an average particle size or less.
A latex of polyorganosiloxane rubber is prepared by emulsion polymerization, and a monomer for synthesizing a conjugated diene rubber is added to this latex, and the polyorganosiloxane rubber particles in the latex are impregnated. Preferably, a rubber is obtained.

The polyorganosiloxane rubber can be prepared by emulsion polymerization using the following organosiloxane and a crosslinking agent for polyorganosiloxane rubber (hereinafter referred to as crosslinking agent (I)). In this case, a grafting agent for polyorganosiloxane rubber is used. (Hereinafter, referred to as a graft crossing agent (I)).

Examples of the organosiloxane include cyclic organosiloxanes having three or more membered rings, and those having a three to six membered ring are preferably used. Hexamethylcyclotrisiloxane as specific examples of preferred cyclic organosiloxanes,
Octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane,
Tetramethyltetraphenylcyclotetrasiloxane,
Octaphenylcyclotetrasiloxane and the like can be exemplified,
These may be used alone or as a mixture of two or more.
The amount of the cyclic organosiloxane used is preferably 50% by weight or more in the polyorganosiloxane rubber.
It is more preferable that the content be not less than% by weight.

As the crosslinking agent (I), a trifunctional or tetrafunctional silane crosslinking agent, that is, a silane compound having three or four alkoxy groups is used. Specific examples thereof include trimethoxymethylsilane and triethoxy. Examples thereof include phenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, and tetrabutoxysilane. The crosslinking agent (I) is preferably a tetrafunctional one, and among the tetrafunctional crosslinking agents, tetraethoxysilane is particularly preferred. The amount of the crosslinking agent (I) to be used is preferably 0.1 to 30% by weight, more preferably 0.5 to 10% by weight in the polyorganosiloxane rubber.

The grafting agent (I) is represented by the following formula:

[0018]

Embedded image

(In each formula, R ¹ represents a methyl group, an ethyl group, a propyl group or a phenyl group, R ² represents a hydrogen atom or a methyl group, n represents 0, 1 or 2, and p represents an integer of 1 to 6. A compound capable of forming the unit represented by the formula (1) is used.

(Meth) capable of forming a unit of the formula (I-1)
Acryloyloxysiloxane can form an effective graft chain because of its high grafting efficiency, and is advantageous in terms of exhibiting impact resistance. Note that methacryloyloxysiloxane is particularly preferable as a unit capable of forming the unit of the formula (I-1).

Specific examples of methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, and γ-methacryloyloxypropyltrimethoxysilane. Examples thereof include methacryloyloxypropylethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, and δ-methacryloyloxybutyldiethoxymethylsilane. The amount of the grafting agent (I) used is 0 to 10% by weight in the polyorganosiloxane rubber.

The polyorganosiloxane rubber can be produced by the methods described in, for example, US Pat. Nos. 2,891,1920 and 3,247,725. In the present invention, for example, a mixed solution of an organosiloxane, a crosslinking agent (I) and, if desired, a graft crosslinking agent (I) is mixed with a homogenizer in the presence of a sulfonic acid emulsifier such as alkylbenzenesulfonic acid or alkylsulfonic acid. It is preferable to produce by mixing with water using shearing. Alkylbenzene sulfonic acid is suitable because it acts as an emulsifier for the organosiloxane and also serves as a polymerization initiator. In this case, it is preferable to use an alkylbenzene sulfonic acid in combination with a metal salt of an alkylbenzene sulfonic acid, a metal salt of an alkyl sulfonic acid, or the like, since this is effective for stably maintaining the polymer during graft polymerization.

The latex obtained by the polymerization is neutralized with an aqueous alkali solution such as sodium hydroxide, potassium hydroxide, sodium carbonate or the like, thereby terminating the polymerization of the organosiloxane and obtaining a polyorganosiloxane rubber latex.

The conjugated diene rubber component used in the present invention is obtained by polymerizing 50 to 100% by weight of a conjugated diene monomer and 0 to 50% by weight of a vinyl monomer copolymerizable with the monomer. It is. Examples of the conjugated diene monomer include butadiene, chloroprene, and isoprene, and examples of the vinyl monomer copolymerizable with the conjugated diene monomer include styrene, α-methylstyrene, and aromatic alkenyl compounds such as vinyltoluene. Unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile; and alkyl (meth) acrylates having 1 to 12 carbon atoms in the alkyl group. These monomers may be used in combination of two or more.

The polymerization of the conjugated diene rubber component is carried out by adding the above-mentioned conjugated diene monomer or, if desired, into a latex of a polyorganosiloxane rubber neutralized by adding an aqueous solution of an alkali such as sodium hydroxide, potassium hydroxide or sodium carbonate. After adding a copolymerizable vinyl monomer and impregnating the polyorganosiloxane rubber particles,
The reaction is carried out by the action of a radical polymerization initiator. As the polymerization progresses, a crosslinked network of the polyorganosiloxane rubber forms a complex structure of conjugated diene rubbers entangled with each other, and a latex of a composite rubber of a polyorganosiloxane rubber component and a conjugated diene rubber component, which cannot be separated substantially from each other, is obtained. .

As the polymerization initiator used herein, any of a peroxide initiator, an azo initiator, and a redox initiator obtained by combining a peroxide and a reducing agent can be used. It is preferable to use a redox-based initiator, particularly, a sugar-containing sodium pyrophosphate-based initiator comprising a combination of ferrous sulfate, sodium pyrophosphate, dextrose, and a dialkyl peroxide, and ferrous sulfate, disodium ethylenediaminetetraacetate. -A sulfoxylate-based initiator composed of a combination of Rongalite and hydroperoxide is preferred.

In the polymerization of a conjugated diene rubber in the presence of a polyorganosiloxane rubber latex, a composite rubber having a relatively small particle diameter is easily produced, and the particle diameter is 0.1%.
It may be less than 8 μm. Even if this composite rubber is used as it is to produce a graft copolymer, the obtained graft copolymer has a certain degree of impact resistance-imparting effect, but the particle size of the obtained rubber is increased due to enlargement and the like. It is preferable to set the thickness within the range of 0.18 to 0.4 μm because the effect of imparting impact resistance is further enhanced.

The enlargement method is to partially agglomerate rubber latex to increase the particle size of rubber, and to add a copolymer latex of unsaturated organic acid and alkyl acrylate and to add a salt such as sodium sulfate. There is a method, in the case of the enlargement of the composite rubber of polyorganosiloxane and conjugated diene rubber as in the present invention, it is preferable to use the former method, as the unsaturated organic acid acrylic acid,
One or more selected from methacrylic acid, itaconic acid and crotonic acid are used, and one or more alkyl acrylates having an alkyl group having 1 to 12 carbon atoms are used. The alkyl acrylate may be partially substituted with a monomer such as alkyl methacrylate, styrene, acrylonitrile or the like as long as it is not more than half the amount. The ratio of the organic acid to the alkyl acrylate in the copolymer of the copolymer latex for enlargement is 3 to 30% by weight in the former and 9 in the latter.
What is 7 to 70 weight% is used preferably. If the organic acid content is less than 3% by weight, the swelling ability is small,
Exceeding the weight percent is not preferable because a large amount of coagulation is generated during the emulsion polymerization of the copolymer.

The particle size of the enlarged composite rubber can be adjusted by the amount of the copolymer latex added. The amount of the copolymer latex to be added depends on the particle diameter of the composite rubber before the enlargement and the particle diameter of the composite rubber to be obtained by the enlargement. ~ 1
It is preferable to add 0 parts by weight. If the amount is less than 0.1 part by weight, the effect of enlargement is small.

The particle size of the composite rubber can be determined by measuring the particle size of an ultrathin section of the composite rubber using a transmission electron microscope. In the present invention, the particle diameter of 150 to 200 ultra-thin section particles was measured using an electron micrograph at a magnification of 20,000, and the number average particle diameter was calculated.

In the practice of the present invention, the main skeleton of the polyorganosiloxane rubber component has a repeating unit of dimethylsiloxane, the conjugated diene rubber component is butadiene, and the repeating unit of trans-1,4-polybutadiene is a main component. The composite rubber obtained by enlarging the composite rubber to be used with a latex of a copolymer of butyl acrylate and methacrylic acid is preferably used. Such a composite rubber can be subjected to graft polymerization with a vinyl monomer.

Examples of the vinyl monomer to be graft-polymerized on the composite rubber include aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyl toluene; methacryl such as methyl methacrylate and 2-ethylhexyl methacrylate. Acid esters; acrylic esters such as methyl acrylate, ethyl acrylate and butyl acrylate;
Examples include various vinyl monomers such as vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and these may be used alone or in combination of two or more.

The ratio of the composite rubber to the vinyl monomer in the composite rubber-based graft copolymer is 15 to 95% by weight of the composite rubber and 5 to 85% by weight based on the weight of the graft copolymer. %, More preferably 25 to 90% by weight of the composite rubber and 10 to 75% by weight of the vinyl monomer. 5% by weight of vinyl monomer
Less than, when this copolymer is blended with another thermoplastic resin, the dispersion of the graft copolymer in the resin is not sufficient,
On the other hand, when the content exceeds 85% by weight, the effect of imparting impact resistance is undesirably reduced. The composite rubber-based graft copolymer is obtained by adding the above-mentioned vinyl monomer to the composite rubber latex and polymerizing the composite rubber-based graft copolymer latex by one-step or multi-step polymerization by radical polymerization technology, using calcium chloride or aluminum sulfate. Such a metal salt is poured into hot water in which it is dissolved, and salted out and coagulated to be separated and recovered. At this time, it is preferable to add antioxidants and stabilizers such as hindered phenol and thioether.

The composite rubber-based graft copolymer obtained in the present invention can be used as an impact-resistant resin by itself, but can be used by mixing with various thermoplastic resins.

The thermoplastic resin which can improve the impact resistance by adding the composite rubber-based graft copolymer includes a mixture of a polyphenylene ether resin and a polystyrene resin,
70 to 100% by weight of at least one vinyl monomer selected from the group consisting of a polycarbonate resin and / or a polyester resin, an aromatic alkenyl compound, a vinyl cyanide compound and a (meth) acrylate ester %, And a homopolymer or copolymer obtained by polymerizing 0 to 30% by weight of another vinyl monomer copolymerizable therewith.

As a method for adding the graft copolymer of the present invention to a resin, a method of mechanically mixing and shaping into pellets using a known device such as a Banbury mixer, a roll mill, a twin screw extruder or the like. Can be mentioned. Extruded shaped pellets can be molded in a wide temperature range,
An ordinary injection molding machine is used for molding.

Further, a plasticizer, a lubricant, a flame retardant, a pigment, a filler, a fiber reinforcing agent, and the like can be added to the resin composition as required.

[0038]

The present invention will be described in detail with reference to the following examples. In the following description, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.
The methods for measuring the Izod impact strength and the surface hardness (Rockwell hardness) in each of the examples and comparative examples are as follows. Izod impact strength: According to the method of ASTM D-256. (With 1/4 "notch) Rockwell hardness: According to the method of ASTM D-785.

REFERENCE EXAMPLE 1 Polymerization of Latex for Enlargement In a separable flask equipped with a condenser and a stirrer, 200 parts of distilled water and 3 parts of an anionic emulsifier were dissolved.
° C., after replacing with nitrogen, ferrous sulfate 0.01 part,
After adding a mixture of 0.03 part of disodium ethylenediaminetetraacetic acid, 0.2 part of Rongalit and 5 parts of distilled water, 85 parts of n-butyl acrylate, 15 parts of methacrylic acid and 0.4 part of cumene hydroperoxide were added. Mix 2
After that, the mixture was kept at 70 ° C. for 3 hours and cooled to obtain a latex of a copolymer of n-butyl acrylate and methacrylic acid. The conversion of the monomer was 97% and the pH was 6.2. In the following examples, in the case of enlargement, this latex was used.

Example 1 2 parts of tetraethoxysilane, 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and 97.5 parts of octamethylcyclotetrasiloxane were mixed to obtain 100 parts of a siloxane mixture. Next, 200 parts of distilled water in which 0.67 part of dodecylbenzenesulfonic acid and 0.67 part of sodium dodecylbenzenesulfonate were dissolved was prepared, and 100 parts of the above siloxane mixture was added thereto.
The mixture was preliminarily stirred at 10,000 rpm and emulsified with a homogenizer at a pressure of 200 kg / cm ² to obtain an organosiloxane latex.

The organosiloxane latex was transferred to a separable flask equipped with a condenser and a stirring blade, and heated at 80 ° C. for 5 hours while stirring and mixing.
After standing at 20 ° C. for 8 hours, the pH of this latex was neutralized to 7.5 with an aqueous sodium hydroxide solution to obtain a polyorganosiloxane rubber latex (hereinafter referred to as polyorganosiloxane rubber latex-1). The polymerization rate of the obtained polyorganosiloxane rubber was 88.6%,
The average particle size of the polyorganosiloxane rubber is 0.12μ
m.

34.2 parts of this polyorganosiloxane rubber latex-1 was collected, placed in an autoclave equipped with a stirrer, and charged with 195 parts of distilled water and 2.0 parts of potassium oleate.
And a mixture of 0.2 parts of dextrose, and after the atmosphere was replaced with nitrogen, the pressure was reduced to 50 mmHg, and a mixture of 90 parts of butadiene, 0.24 part of cumene hydroperoxide and 0.6 part of tert-dodecyl mercaptan was autoclaved. And the temperature of the solution was raised to 55 ° C. When the temperature reached 50 ° C. during the heating, a mixed solution of 0.0036 parts of ferrous sulfate, 0.3 parts of sodium pyrophosphate and 5 parts of distilled water was introduced into an autoclave to start polymerization. Thereafter, the mixture was kept at an internal temperature of 55 ° C. for 7 hours to obtain a composite rubber latex. A part of this latex was collected and the average particle size of the composite rubber was measured.
It was 14 μm, and the conversion of butadiene was 92.8%.

157 parts of this composite rubber latex were collected, and 3 parts of the latex for enlargement obtained in Reference Example 1 was added thereto at room temperature, and the mixture was stirred for 30 minutes to enlarge the particles, and then potassium oleate was added. An aqueous solution of 1.0 part dissolved in distilled water was added to stop the enlargement. A part of the composite rubber latex after the enlargement was sampled, dropped into methanol to separate the composite rubber, and dried to obtain a solid substance.
Extracted at 12 ° C. for 12 hours and measured for gel content.
The swelling degree after immersion in toluene at 23 ° C. for 24 hours was 32.6%. The number average particle diameter of the composite rubber after the enlargement was 0.24 μm.

The temperature of the composite rubber latex was raised to 70 ° C., and 12.5 parts of acrylonitrile, 37.5 parts of styrene, and 0.225 part of cumene hydroperoxide were added thereto as the first stage of graft polymerization. The liquid was added dropwise over 60 minutes, and then the liquid temperature was maintained at 75 ° C. for 50 minutes. Then, 12.5 parts of acrylonitrile, 37.5 parts of styrene, 0.1 part of octyl mercaptan were used as the second stage of graft polymerization. Cumene hydroperoxide 0.225
Of the mixture was dropped over 60 minutes, and then the solution temperature was maintained for 60 minutes to complete the polymerization. The polymerization rates of acrylonitrile and styrene were 98.9% and 98.1%, respectively, and the number average particle diameter of the graft copolymer was 0.27 μm.

The graft copolymer latex obtained above was gradually added dropwise to the heated 5% by weight sulfuric acid aqueous solution while stirring, and the graft copolymer was coagulated, filtered and dried. This was supplied to a twin-screw extruder (ZSK-30, manufactured by Werner & Faudler), and the cylinder temperature was set to 240.
The mixture was melted and kneaded at ℃, shaped into pellets, and the obtained pellets were subjected to injection molding machine (Promat 165 type: Sumitomo Heavy Industries, Ltd.) at a cylinder temperature of 240 ° C. and a mold temperature of ℃ ″ at 60 ° C. , 1/8 "thick test pieces were injection molded and measured for Izod impact strength (23 ° C, 1/4" notch) and Rockwell hardness. Izod impact strength was 39.
5 kg · cm / cm, Rockwell hardness (R scale)
It was 6.

Examples 2 to 6 The ratio of polyorganosiloxane rubber latex-1 to polybutadiene was adjusted to be as shown in Table 1, and cumene hydroperoxide and te were used during the polymerization of polybutadiene.
The amount of rt-dodecyl mercaptan was 0.27 parts each;
An enlarged composite rubber latex was obtained in the same manner as in Example 1 except that the amount was 67 parts, and the gel content, the degree of swelling, and the number average particle diameter of the composite rubber latex were measured. A composite rubber-based graft copolymer was obtained in the same manner as in Example 1, and a test piece was prepared from these graft copolymers and evaluated. Table 1 shows the results.

[0047]

[Table 1]

From the above table, it can be seen that good performance is exhibited when the ratio of polyorganosiloxane rubber to polybutadiene in the composite rubber is wide.

Comparative Examples 1 and 2 The same procedure as in Example 1 was repeated except that polyorganosiloxane rubber latex-1 (gel content: 90.8, swelling degree: 19.9) was used instead of using the composite rubber latex. Graft polymerization was performed (Comparative Example 1). The performance of the obtained graft copolymer was such that the Izod impact strength was 18.7 kg.
-Rockwell hardness (R scale) of 85.7 in cm / cm
Met.

Also, butadiene was polymerized in the same manner as in Example 1 except that the amount of butadiene introduced into the autoclave was changed to 100 parts without using the polyorganosiloxane rubber latex-1. The number average particle diameter of the obtained polybutadiene was 0.07 μm, and the conversion of butadiene was 95.7%. Enlargement and graft polymerization were carried out in the same manner as in Example 1 except that the same amount of the polybutadiene latex obtained above was used instead of the composite rubber latex, and the performance of the obtained graft copolymer was measured. The gel content, degree of swelling, and number average particle diameter of the enlarged polybutadiene are 89.0%, 31.7, and 0.29 μm, respectively.
The Izod impact strength of the graft copolymer is 15.8 kg · c
m / cm and Rockwell hardness (R scale) were 76.9 (Comparative Example 2).

From a comparison between Comparative Examples 1 and 2 and each of the examples, it can be seen that when the rubber is not made into a composite rubber, the Rockwell hardness of the impact strength does not become a good performance.

Examples 7 to 9, Comparative Examples 3 to 5 A graft copolymer was obtained in the same manner as in Example 1 except that the amount of mercaptan used in the polymerization of butadiene was changed to the amount shown in Table 2, and Izod strength and Rockwell The hardness was measured. Table 2 shows the gel content and the degree of swelling of the obtained composite rubber. The number average particle size of the composite rubber after the enlargement was 0.24 μm regardless of the amount of mercaptan. Although the gel content was 80% by weight or more and the degree of swelling was 10 to 40, the impact resistance and Rockwell hardness were good.

[0053]

[Table 2]

Example 10 160 parts of the composite rubber latex prepared in Example 1 was collected and heated to 70 ° C. without any enlargement treatment, and 12.5 parts of acrylonitrile and 3 parts of styrene were added thereto.
A mixture of 7.5 parts and 0.225 parts of cumene hydroperoxide was added dropwise over 60 minutes.
After holding for 2 minutes, acrylonitrile 1
A mixture of 2.5 parts, 37.5 parts of styrene, 0.1 part of octyl mercaptan, and 0.225 part of cumene hydroperoxide was added dropwise over 60 minutes, and after the completion of the addition, the liquid temperature was further maintained for 60 minutes. The polymerization was terminated. The polymerization rates of acrylonitrile and styrene were 97.5% and 96.2%, respectively, and the number average particle diameter of the graft copolymer was 0.16 μm. The graft copolymer was recovered from this latex in the same manner as in Example 1 and subjected to extrusion molding and injection molding, and the Izod impact strength and Rockwell hardness (R scale) were measured. Izod impact strength is 24.8kg ・ cm /
cm and a Rockwell hardness of 104.

Example 11 157 parts of the composite rubber latex obtained in Example 1 were collected,
The swelling treatment was carried out in the same manner as in Example 1, the swelling composite rubber latex was heated to 70 ° C., and methyl methacrylate 30
And a mixture of 0.2 parts of cumene hydroperoxide was added dropwise over 60 minutes, and then graft polymerization was carried out at 70 ° C. for 60 minutes, and grafting was carried out from the obtained latex in the same manner as in Example 1. The copolymer was recovered, subjected to extrusion molding and injection molding, and the Izod impact strength and Rockwell hardness (R scale) were measured. Izod impact strength is 21.2 kg · cm / cm and Rockwell hardness is 91
Met.

As described above, the composite rubber-based graft copolymer of the present invention itself is a molded article having excellent impact resistance and surface hardness, and has improved impact resistance when added to other resins. It also shows excellent performance as an impact resistance improver.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-191661 (JP, A) JP-A-2-199109 (JP, A) JP-A-2-47152 (JP, A) JP-A-62-162 212406 (JP, A) JP-A-3-281561 (JP, A) JP-A-1-165657 (JP, A) JP-A-53-24347 (JP, A) JP-A-1-121131 (JP, A) Japanese Patent Application Laid-Open No. 4-1222763 (JP, A) Japanese Patent Application Laid-Open No. 3-231907 (JP, A) Japanese Patent Application Laid-Open No. 63-69859 (JP, A) Japanese Patent Application Laid-Open No. 60-252613 (JP, A) (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) C08F 251/00-292/00 C08F 299/00-299/08

Claims (1)

(57) [Claims] 1. A polyorganosiloxane rubber component 1 to 99.
% By weight and a conjugated diene rubber component of 99 to 1% by weight, having a structure in which both components are entangled with each other so that they cannot be separated from each other, and a gel content measured using a toluene solvent is 80% or more; A composite rubber-based graft copolymer obtained by graft-polymerizing one or more vinyl monomers onto a composite rubber having a swelling degree of 10 to 40.