JP3151481B2 - Method for producing rubber-modified copolymer resin and rubber-modified copolymer resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an improved rubber-modified copolymer resin and a rubber-modified copolymer resin composition containing the same, and more particularly to a specific styrene-butadiene. Transparency obtained by graft copolymerization of a styrene monomer and an alkyl (meth) acrylate in the presence of a copolymer rubber, and excellent impact resistance, especially practical strength represented by falling weight impact strength, and The present invention relates to a method for producing a rubber-modified copolymer resin having good appearance and hue of a molded article, and a rubber-modified copolymer resin composition containing the same.

<Related Art> Conventionally, as a resin having transparency and impact resistance, a terpolymer resin obtained by graft copolymerizing styrene and methyl methacrylate in the presence of a rubbery polymer is known.

<Problem to be Solved by the Invention> In this case, for example, in a resin having a rubbery polymer content of 3 to 5% by weight and an average rubber particle diameter of about 1.0 μm,
Poor impact resistance, not satisfactory. However, when the amount of rubber in the resin is increased in order to increase the impact strength, the transparency is significantly reduced. Therefore, in order to obtain a material having excellent transparency, a method of reducing the average rubber particle diameter to a region of 0.1 to 0.2 μm to increase the amount of rubber, or a rubber phase and an average rubber having an average rubber particle diameter of 0.5 μm or less are used. A method of mixing a rubber phase having a particle diameter larger than 0.5 μm (Japanese Patent Publication No. 44-1954) is known, but the impact strength, particularly the falling weight impact strength, which is a practical physical property, is significantly improved. On the other hand, when the content of the rubbery polymer exceeds 10% by weight, there is a disadvantage that rigidity such as flexural strength and flexural modulus decreases and yellowing occurs during molding.

<Means for Solving the Problems> The inventors of the present invention have conducted intensive studies in view of such a situation, and have found that the ratio of 1,2-vinyl bonds among unsaturated bonds based on butadiene as a rubbery polymer is reduced. When a styrene-butadiene copolymer rubber, which is a block copolymer of 14 to 25% and 5 to 40% by weight of styrene and 95 to 60% by weight of butadiene, is used, the transparency is good and the impact strength, especially A rubber-modified copolymer resin having excellent practical strength represented by weight impact strength can be obtained, and the copolymer resin has a good balance between the degree of grafting and the degree of crosslinking of the copolymer rubber in the resin, The inventors have found that the toluene insoluble content, the swelling index with toluene, and the ratio thereof are within a specific range, and have completed the present invention.

That is, the present invention relates to a block copolymer comprising 14 to 25% of a 1,2-vinyl bond among butadiene-based unsaturated bonds, and 5 to 40% by weight of styrene and 95 to 60% by weight of butadiene. In the presence of the styrene-butadiene copolymer rubber (A), the styrene monomer (B) and the alkyl (meth) acrylate (C) have a weight ratio of (B) / (C) of 30 / 70-60. /
40, and the obtained resin has a toluene insoluble content at 25 ° C of 4 to 22% by weight, a toluene swelling index at 25 ° C of 11 to 19, and a toluene insoluble content /
A process for producing a transparent rubber-modified copolymer resin characterized by graft copolymerization such that the swelling index becomes 0.15 to 1.10% by weight; and a styrene monomer (B) in the presence of a styrene-butadiene copolymer rubber (A). ) And an alkyl (meth) acrylate (C) by graft copolymerization, and
The toluene-insoluble content at 25 ° C. is 4 to 22% by weight, and
A transparent rubber-modified copolymer resin having a swelling index with toluene at 25 ° C of 11 to 19 and a toluene insoluble content / swelling index of 0.15 to 1.10% by weight.

Is provided.

As the styrene-butadiene copolymer rubber (A) used in the present invention, any of those having a 1,2-vinyl bond ratio of 14 to 25% among the unsaturated bonds based on butadiene as an essential component can be used. Yes, but especially 16-22%
Are preferred, the remainder being cis and trans bonds. Styrene containing less than 14% of 1,2-vinyl bonds
When butadiene copolymer rubber is used, the content of toluene-insoluble components in the rubber-modified copolymer resin decreases, and a product excellent in impact resistance cannot be obtained. Crosslinking at high temperature during production progresses, and the balance between the grafting rate and the degree of crosslinking is lost, and the toluene insoluble content / swelling index becomes larger than 1.10% by weight, and the rubber elasticity decreases. After all, those having excellent impact resistance cannot be obtained.

As the copolymer rubber (A), those having a 5% by weight styrene solution viscosity of 5 to 40 centipoise are more preferable because the effect of improving the impact strength is large and the rubber particle diameter can be easily controlled during production. In particular, the viscosity of a 5% by weight styrene solution at 25 ° C. is 10 to 30 centipoise, and
Those having a Mooney viscosity of 20 to 80 using an L rotor at 0 ° C are preferred.

The bonding mode of styrene and butadiene in the copolymer rubber (A) is block bonding, and the weight ratio of styrene / butadiene is 5 /
It should be 95-40 / 60.

The styrene monomer (B) used in the present invention includes:
For example, styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, ethylstyrene, isobutylstyrene, tertiarybutylstyrene, o-bromostyrene, m-bromostyrene,
Examples include p-bromostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene and the like, with styrene being preferred.

Examples of the alkyl (meth) acrylate (C) include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and iso-butyl (meth) acrylate. Of these, methyl methacrylate is particularly preferred.

The weight ratio of the copolymer rubber (A), the styrene monomer (B) and the alkyl (meth) acrylate (C) is usually (A) / [(B) + (C)] by weight. 99 ~
20/80, and the weight ratio of (B) / (C) is 30 / 70-60 / 40
Among them, (A) / A is excellent in transparency and impact resistance and high rigidity can be obtained.
It is preferable that the weight ratio of [(B) + (C)] is 3/97 to 15/85 and the weight ratio of (B) / (C) is 30/70 to 60/40.

To produce the transparent rubber-modified copolymer resin of the present invention,
In the presence of the copolymer rubber (A), the styrene monomer (B) and the alkyl (meth) acrylate (C) are used as essential components, and if necessary, other copolymerizable monomers (D ) May be graft-copolymerized by suspension polymerization, solution polymerization or bulk polymerization. Among them, bulk polymerization is preferable. In particular, a tubular reactor in which a plurality of mixing elements having no moving parts are fixed is incorporated. In a continuous bulk polymerization line, if continuous bulk polymerization is performed while performing static mixing by the tubular reactor, the rubber particle diameter can be easily controlled in a state where the rubber particle diameter distribution is narrow even if the rubber particle diameter is small. This is preferable in that a rubber-modified copolymer resin having excellent transparency and impact resistance can be efficiently produced.

Examples of other copolymerizable monomers (D) used herein include vinyl (meth) acrylonitrile and the like.
Cyan compounds; itaconic acid, maleic acid, fumaric acid,
Polymerizable unsaturated fatty acids such as crotonic acid and cinnamic acid; N-methylmaleimide, N-ethylmaleimide, N-butylmaleimide, N-octylmaleimide, N-isopropylmaleimide, N-phenylmaleimide, Np-bromophenylmaleimide , No-chlorophenylmaleimide,
Maleimides such as N-cyclohexylmaleimide; unsaturated carboxylic anhydrides represented by maleic anhydride, itaconic anhydride, citraconic anhydride and the like; allylamine;
Amino group-containing unsaturated compounds such as aminoethyl (meth) acrylate and aminopropyl (meth) acrylate; acrylamide compounds such as acrylamide and N-methylacrylamide; 2-hydroxyethyl-acrylate, 3
And hydroxy-containing unsaturated compounds such as -hydroxypropyl methacrylate and 4-hydroxy-2-butene. Among them, acrylonitrile is preferable.

In the following, a rubber modified copolymer using a continuous bulk polymerization line incorporating a tubular reactor having a plurality of mixing elements without moving parts fixed inside (hereinafter abbreviated as a tubular reactor having a static mixing element) will be described. An example of a method for producing a polymer resin will be described with reference to the drawings.

FIG. 1 is a process diagram showing an example of a continuous bulk polymerization line incorporating a tubular reactor having a static mixing element.

The mixed solution containing (A), (B) and (C) as the essential components supplied by the plunger pump (1) is first sent to the stirred reactor (2) as necessary,
After initial graft polymerization under stirring, gear pump (3)
Feeds into a circulating polymerization line (I) having tubular reactors (4), (5) and (6) with static mixing elements and a gear pump (7).

The initial graft polymerization in the stirred reactor (2) is not always necessary, but if it is performed within a range in which extra shear is not applied to the rubber particles, the rubber particles can be more efficiently refined. From the viewpoint that the average residence time of the mixed solution in the circulation polymerization line (I) can be shortened. In the initial graft polymerization in this case, the total polymerization conversion of the styrene monomer (B) and the alkyl (meth) acrylate (C) is 10 to 28% by weight at the outlet of the reactor (2).
It is preferably carried out so as to be 14 to 24% by weight. Further, as the stirred reactor (2), for example, a stirred tank reactor,
Stirred tower reactors and the like can be mentioned. Examples of the stirring blades include anchor type, turbine type, screw type and double helical type stirring blades.

In the present invention, a solvent may be used to reduce the viscosity of the mixed solution in the reactor, and the amount of the solvent used is 5 to 20 parts by weight based on 100 parts by weight of the total amount of the raw material monomers. As the type of the solvent, toluene, ethylbenzene, xylene and the like which are usually used in the bulk polymerization method are suitable.

Further, in the present invention, it is preferable to add a chain transfer agent to the mixed solution for controlling the molecular weight of the rubber-modified copolymer resin. The amount of the chain transfer agent is usually in the range of 0.05 to 0.5 part (500 to 5000 ppm) based on 100 parts by weight of the total amount of the raw material monomers.

The mixed solution initially graft-polymerized with dynamic stirring as described above is then graft-polymerized while circulating in the circulation polymerization line (I), and part of the mixture is continuously static-mixed. The tubular reactors (8), (9) and (10) with elements are sent to a non-circulating polymerization line (II) incorporated in series.

The rubber particles in the mixed solution in the circulation polymerization line (I) are statically mixed and stabilized while circulating in the circulation polymerization line (I), and the particle diameter is also fixed. In this case, the important factors are the reflux ratio (R) of the mixed solution in the circulation polymerization line (I) and the total polymerization conversion rate of the styrene monomer (B) and the alkyl (meth) acrylate (C). .

The reflux ratio R is the flow rate of the mixed solution that refluxes in the circulation polymerization line (I) without flowing out to the non-circulation polymerization line (II).
₁ (/ hour) and the flow rate F ₂ (/ hour) of the mixed solution flowing from the circulation polymerization line (I) to the non-circulation polymerization line (II), R = F ₁ / F ₂ is usually 3 to 15 Above all, the pressure loss in the tubular reactor is small, the resulting rubbery polymer particles are stable, the particle size can be reduced, and the styrene monomer (B ) And (meth) acrylic acid alkyl ester (C) are particularly preferably in the range of R = 5 to 10 in that the content ratio can be kept constant.

Further, the graft polymerization in the circulating polymerization line (I) includes:
The total polymerization conversion of the styrene monomer (B) and the alkyl (meth) acrylate (C) at the outlet of the circulation polymerization line (I) is usually 35 to 55% by weight, preferably 40 to 55% by weight.
Polymerize so as to be ~ 55% by weight. The polymerization temperature is 12
0-135 ° C is suitable.

The mixed solution graft-polymerized in the circulation polymerization line (I) is then supplied to the non-circulation polymerization line (II),
Graft polymerization is carried out continuously at a polymerization temperature of 0 to 160 ° C. until the total conversion of the styrene monomer (B) and the alkyl (meth) acrylate (C) becomes 60 to 75% by weight.

Next, this mixed solution is sent to a preheater (not shown) by a gear pump (11), and then to a devolatilization tank (not shown).
After removing the unreacted monomer and the solvent under reduced pressure, the resulting transparent rubber-modified copolymer resin is obtained by pelletizing. At this time, it is preferable to perform the preheating and the devolatilization under the condition that the increase in the conversion rate in the preheater and the devolatilization tank is 7% by weight or less.

As the plurality of mixing elements fixed inside the tubular reactor having the static mixing element used in the present invention, for example, the division and the flow direction of the flow of the polymer solution flowing into the tube are repeated, and the division and the merge are repeated. For mixing the polymerization liquid. As such a tubular reactor, for example, SMX type, SMR type Sulzer type tubular mixer, Kenix type static mixer,
Toray-type tubular mixers and the like are preferred.

The number of these tubular reactors to be incorporated into the circulation polymerization line (I) or the non-circulation polymerization line (II) is not particularly limited in the case of the above-mentioned tubular reactor because it differs depending on the length thereof, the structure of the mixing element, and the like. And 4 to 15, preferably 6 to 10 tubular reactors each having four or more mixing elements. The number of the tubular reactors to be incorporated in the circulation polymerization line (I) is usually 1
1010, preferably 2-6.

To the mixed solution used as a raw material in the present invention, if necessary, by adding an organic peroxide that releases free radicals when decomposed as a polymerization initiator, kraft formation and reaction promotion at a relatively low temperature can be performed. It is preferred. The added amount is 0.005 to 0.04 with respect to 100 parts by weight of the total amount of the raw material monomers.
It is in the range of parts by weight (50-400 ppm).

The organic peroxide used here is preferably one having a temperature at which the half-life becomes 10 hours at 75 to 170 ° C., and specific examples thereof include 1,1-di-t-butylperoxycyclohexane, 1,1- Di-tert-butylperoxy-3,3,5-trimethylcyclohexane, 2,2-di-tert-butylperoxyoctane, n-butyl-4,4-di-tert-butylperoxyvalerate, 2, Peroxy ketals such as 2-di-t-butyl peroxybutane; t-butyl peroxy acetate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy laurate, t -Butylperoxybenzoate, di-t-butyldiperoxyisophthalate, 2,5-dimethyl-2,5-dibenzoylperoxyhexane, t-butylperoxymaleic acid, t-butylperoxyisopropyl car Bonate,
Peroxyesters such as di-t-butyl peroxide, sicumyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide and the like can be mentioned, and these are used alone or in combination of two or more.

Further, the mixed solution used in the present invention may contain, if necessary, a plasticizer such as a mineral oil, an antioxidant, a chain transfer agent, a release agent such as a long-chain fatty acid, an ester or a metal salt thereof, and a silicone oil. A known additive such as described above may be used in combination.

According to the production method of the present invention described above, the content of toluene-insoluble matter at 25 ° C. is 4 to 22% by weight, and the swelling index by toluene is
11-19 and the toluene insoluble content / swelling index is 0.15
A transparent rubber-modified copolymer resin having an average rubber particle diameter of 0.3 to 1.2 μm, particularly 0.4 to 0.8 μm is preferred.

The transparent rubber-modified copolymer resin includes a styrene-based monomer (B) which is a matrix phase in the resin.
Weight average molecular weight (w) of the copolymer of styrene and alkyl (meth) acrylate (C) is 100,000 to 180,000, and the ratio w / w of weight average molecular weight (w) to number average molecular weight (n)
Those having n of 1.8 to 2.5 are preferred, and those having a weight average molecular weight (w) of 130,000 to 160,000 are particularly preferred.

The transparent rubber-modified copolymer resin of the present invention thus obtained is further used as an antioxidant, a plasticizer,
An ultraviolet absorber, a lubricant, a flame retardant, an antistatic agent, a foaming agent, a reinforcing material, and the like can be added.

Among these, preferred are, for example, mineral oil, ester-based plasticizer, polyester-based plasticizer,
Examples thereof include organic polysiloxanes, higher fatty acids and metal salts thereof, hindered phenolic antioxidants, and glass fibers, which can be used alone or in combination. In particular, ester plasticizers and polyester plasticizers are effective as flow improvers during melting of the transparent rubber-modified copolymer resin of the present invention, and have the advantage of not lowering the transparency.

Further, the transparent rubber-modified copolymer resin of the present invention can be used as various molded articles by a molding method such as injection molding, extrusion molding, vacuum molding, pressure molding, blow molding and the like. Its applications are wide-ranging, such as parts for household appliances and appliances such as radio cassettes, audio players, video tape recorders, etc .; cameras, printers,
Used as various parts of OA equipment such as facsimile and personal computers; food containers; parts of medical instruments and the like. Further, the transparent rubber-modified copolymer resin of the present invention, if necessary, AS resin, ABS resin, styrene-methyl methacrylate copolymer resin, rubber-modified styrene-methyl methacrylate copolymer resin, acrylic resin, styrene-anhydride A thermoplastic resin such as a maleic acid copolymer resin or a vinyl chloride resin may be appropriately added.

The method for measuring the average particle size of the rubbery polymer, the content of toluene-insoluble matter and the swelling index with toluene is described below.

Average particle size of rubbery polymer in resin A transmission electron micrograph was taken of the resin by an ultra-thin section method, the particle size of 1000 particles in the photograph was measured, and the average particle size was determined by the following formula.

(However, n _i is the number of rubber particles having a particle size D _i.) It was precisely weighed swelling index rubber-modified copolymer resin 1g with toluene insolubles content and toluene, toluene 100 ml 25
After dissolving at 24 ° C. for 24 hours, the lysate was transferred to a centrifuge tube, centrifuged at 10 ° C. or lower at 8500 rpm for 15 minutes, and the supernatant was removed by decantation. Measure the weight. Next, it is dried in a vacuum dryer at 60 ° C. for 24 hours, the weight of the obtained toluene-insoluble component is measured, and the content of the toluene-insoluble component is calculated by the following equation.

<Example> Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples. However, all parts in the examples are parts by weight, and all percentages are percentages by weight except for the total light transmittance and the ratio of 1,2-vinyl bonds.

 The physical properties in the examples were measured as follows.

(1) Dropping weight impact strength Injection molding machine with cylinder temperature of 240 ° C (Japan Steel Works J150S
Box-shaped molded product (180mm × 126) injection-molded using SII A)
mm × 25mm, wall thickness 2mm) with the bottom facing up, drop a steel ball weighing 1kg at the center, and drop weight impact strength by the product of the height of the ball and the weight of the steel ball up to destruction I asked for it.

(2) Izod impact value, flexural strength and flexural modulus Based on JIS K-6871.

(3) Total light transmittance and haze A test piece with a thickness of 2 mm was prepared by injection molding, and subjected to ASTM D-1003.
The value was determined in accordance with.

(4) Yellowing of Molded Article After staying in a cylinder at 240 ° C. for 5 minutes, the degree of yellowing of the injection-molded box-shaped molded article was visually evaluated.

：: no yellowing Δ: slightly yellowing X: yellowing Example 1 In this example, devices arranged as shown in FIG. 1 were used. A mixed solution containing styrene, methyl methacrylate, a rubbery polymer and a solvent is supplied to a plunger pump (1).
To 20 stirred reactors (2) for initial graft polymerization under dynamic mixing with stirring blades. Next, the mixed solution is circulated by a gear pump (3) into a circulating polymerization line (I).
Send to The circulation polymerization line (I) has an inner diameter of 2.5
Inch tubular reactor (30 built-in static mixers, SMX type, manufactured by Gebruda Sulzer, Switzerland) (4), (5) and (6), and a gear pump (7) for circulating the mixed solution Have been. Between the tubular reactor (6) and the gear pump (7) there is an outlet following the acyclic polymerization line (II).
A tubular reactor (8), (9) and (10) similar to the above and a gear pump (11) are connected in series from the inlet to the non-circulation polymerization line (II).

Styrene-butadiene block copolymer rubber [5% styrene solution viscosity at 25 ° C (hereinafter abbreviated as 5% SV): 20
Centipoise, ratio of 1,2-vinyl bonds: 17%, styrene / butadiene weight ratio: 25/75] 5 parts, styrene 32 parts, methyl methacrylate 62 parts and ethylbenzene 10 parts were prepared. 0.1 part of n-dodecyl mercaptan per 100 parts of the monomer mixture as a chain transfer agent and 0.0 parts per 100 parts of the monomer mixture as an organic peroxide.
Two parts of t-butyl peroxybenzoate were added, and continuous bulk polymerization was carried out using the above apparatus under the following conditions.

Continuous supply rate of mixed solution: 10 / hour Reaction temperature in stirred reactor (2): 120 ° C Reaction temperature in circulating polymerization line (I): 135 ° C Reaction temperature in acyclic polymerization line (II) : 140 ~ 160 ° C. The mixed solution obtained by polymerization is heated to 225 ° C. in a heat exchanger, after removing the volatile components under a reduced pressure of 50 mmHg, the pelletized transparent rubber modified copolymer resin of the present invention I got

Table 1 shows the analysis data and measurement results of physical properties of the resin.

Example 2 Styrene-butadiene block copolymer rubber [5% SV: 1
0 centipoise, 1,2-vinyl bond ratio: 20%, styrene / butadiene weight ratio: 30/70] except that a mixed solution consisting of 3 parts, styrene 39 parts, methyl methacrylate 58 parts and ethylbenzene 10 parts was used. A transparent rubber-modified copolymer resin of the present invention was obtained in the same manner as in Example 1. Table 1 shows the analysis data and the measurement results of the physical properties.

Example 3 Twenty three tank-type reactors (i), (ii) and (iii) equipped with helical stirring blades, a heat exchanger and a devolatilization tank were arranged in series. The polymerization reaction was carried out using a continuous reaction apparatus consisting of 6 parts of a styrene-butadiene block copolymer rubber similar to that used in Example 1, styrene 32
, A mixed solution consisting of 62 parts of methyl methacrylate and 10 parts of ethylbenzene, and 0.1 part of n-dodecylmercaptan and 100 parts of monomer as an organic peroxide were added to 100 parts of the monomer mixture as a chain transfer agent. 0.02 parts of t-butyl peroxybenzoate was added to 100 parts of the mixture,
Using the above apparatus, bulk polymerization was continuously performed under the following conditions.

Continuous supply of mixed solution: 7 / hour Reaction temperature in tank reactor (i): 125 ° C Reaction temperature in tank reactor (ii): 130 ° C Reaction in tank reactor (iii) Temperature: 145 ° C. A transparent rubber-modified copolymer resin of the present invention was obtained in the same manner as in Example 1 below. Table 1 shows the analysis data and measurement results of physical properties.

Comparative Example 1 As a styrene-butadiene block copolymer rubber, 5
% SV is 20 centipoise and the ratio of 1,2-vinyl bonds is 12
%, And a rubber-modified copolymer resin was obtained in the same manner as in Example 1 except that the weight ratio of styrene / butadiene was 25/75. Table 1 shows the analysis data and the measurement results of the physical properties.

<Effect of the Invention> The transparent rubber-modified copolymer resin obtained by the production method of the present invention has excellent transparency and impact resistance, and can be suitably used for various molded products.

[Brief description of the drawings]

FIG. 1 is a process diagram showing an example of a continuous bulk polymerization line incorporating a tubular reactor having a static mixing element. (1)... A plunger pump, (2). 3) a gear pump, (4) a tubular reactor having a static mixing element, (5) a tubular reactor having a static mixing element, and (6) a tubular reactor having a static mixing element. , (7) a gear pump, (8) a tubular reactor having a static mixing element, (10) a tubular reactor having a static mixing element, (I) a circulating polymerization line, (II)
...... Non-circulation polymerization line.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-132112 (JP, A) JP-A-2-34615 (JP, A) JP-A-59-84912 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C08F 279/02 C08F 279/06

Claims (13)

(57) [Claims] 1. An unsaturated bond based on butadiene, comprising:
In the presence of a styrene-butadiene copolymer rubber (A) which is a block copolymer having a 2-vinyl bond ratio of 14 to 25% and 5 to 40% by weight of styrene and 95 to 60% by weight of butadiene, The weight ratio of the monomer (B) and the alkyl (meth) acrylate (C) is (B) / (C).
In the range of 30/70 to 60/40, and the obtained resin is 25
The graft copolymer has a toluene insoluble content of 4 to 22% by weight at 25 ° C, a toluene swelling index of 11 to 19 at 25 ° C, and a toluene insoluble content / swelling index of 0.15 to 1.10% by weight. A process for producing a transparent rubber-modified copolymer resin characterized by polymerizing. 2. A styrene-butadiene copolymer rubber (A)
Is a copolymer rubber having a 5% by weight styrene solution viscosity at 25 ° C. of 5 to 40 centipoise. 3. The weight of (A) / [(B) + (C)] of styrene-butadiene copolymer rubber (A), styrene monomer (B) and alkyl (meth) acrylate (C). 3. The process according to claim 1, wherein the ratio is from 3/97 to 15/85 and the weight ratio of (B) / (C) is from 30/70 to 60/40. 4. The process according to claim 1, wherein the styrene monomer (B) is styrene and the alkyl (meth) acrylate (C) is methyl methacrylate. 5. A styrene-based monomer (B) and an alkyl (meth) acrylate (C) in the presence of a styrene-butadiene copolymer rubber (A), and a plurality of mixing elements having no movable parts are fixed inside. The process according to claim 1, wherein the graft polymerization is carried out in a continuous bulk polymerization line incorporating the tubular reactor. 6. A styrene-butadiene copolymer rubber (A)
6. The process according to claim 5, wherein the copolymer is a copolymer rubber having a 5% by weight styrene solution viscosity at 25 DEG C. of 5 to 40 centipoise. 7. A styrene-butadiene copolymer rubber (A)
Is a block polymer of 5 to 40% by weight of styrene and 95 to 60% by weight of butadiene. 8. The weight of (A) / [(B) + (C)] of styrene-butadiene copolymer rubber (A), styrene monomer (B) and alkyl (meth) acrylate (C). The ratio is 3 / 97-15 / 85 and the weight ratio of (B) / (C) is 3
The method according to claim 5, 6 or 7, which is used in a range of 0/70 to 60/40. 9. The process according to claim 5, wherein the styrene monomer (B) is styrene and the alkyl (meth) acrylate (C) is methyl methacrylate. 10. A mixed solution containing a styrene-butadiene copolymer rubber (A), a styrene monomer (B) and an alkyl (meth) acrylate (C) in a graft copolymerization in a continuous bulk polymerization line. Is graft-copolymerized while circulating in a circulating polymerization line (I) incorporating a tubular reactor in which a plurality of mixing elements without moving parts are fixed, and a part of the polymerization solution is circulated. 6. A non-circulating polymerization line (II) incorporating a tubular reactor, in which a plurality of mixing elements without moving parts, which follow from the polymerization line, are fixed therein, for further graft copolymerization. ,
The production method according to 6, 7, 8 or 9. 11. A styrene-butadiene copolymer rubber (A)
A mixed solution containing styrene-based monomer (B) and alkyl (meth) acrylate (C) is initially graft-copolymerized with stirring, and then further graft-copolymerized in a continuous bulk polymerization line. Item 10. The production method according to Item 10. 12. A graft copolymerization of a styrene monomer (B) and an alkyl (meth) acrylate (C) in the presence of a styrene butadiene copolymer rubber (A), which is insoluble in toluene at 25 ° C. A transparent rubber modified material having a content of 4 to 22% by weight, a swelling index with toluene at 25 ° C. of 11 to 19, and a toluene insoluble content / swelling index of 0.15 to 1.10% by weight. Copolymer resin. 13. The resin according to claim 12, wherein the weight average particle diameter of the styrene-butadiene copolymer rubber (A) in the thermoplastic resin is 0.3 to 1.2 μm.