JPH08239532A - Transparent rubber-modified styrene resin composition and method for producing the same - Google Patents

Abstract

(57) [Summary] [Structure] Styrene 5-50% by weight and butadiene 50-
4 to 30 parts by weight of a rubber-like polymer containing 95% by weight of the specific styrene-butadiene copolymer (A),
Styrene- (meth) acrylic acid alkyl ester copolymer 70 having a refractive index substantially equal to that of the rubber-like polymer
To 96 parts by weight, the rubber-like polymer dispersed in the styrene- (meth) acrylic acid alkyl ester copolymer has an average particle diameter of 0.1 to 2.0 μm and a particle diameter distribution index of 2.0. A transparent rubber-modified styrene resin composition having particles of ˜5.0. [Effect] The resin composition of the present invention has excellent transparency,
It has various uses from impact resistance, especially impact resistance after heat history, and has an extremely great industrial utility value.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rubber-modified styrene resin composition which is excellent in transparency and impact resistance, and particularly in retaining transparency during molding and hue after heat history and impact resistance. And a manufacturing method thereof.

[0002]

2. Description of the Related Art Styrenic resins are excellent in transparency, rigidity, and moldability, so that they can be used in home appliances, OA, etc.
It is used in various applications such as equipment and packaging materials. However, since the styrene resin alone has insufficient impact resistance, it is general to modify the styrene resin with a rubber-like polymer before use. Although this rubber-modified styrenic resin is greatly improved in impact resistance as compared with the unmodified resin, it loses the transparency characteristic originally possessed by the styrene-based resin. This is because the styrene resin and the rubber-like polymer have different refractive indexes.

Polymer Handbook (Third Edition, 〓
/ 451-461), the refractive index of polystyrene is 1.59-
1.592, the refractive index of polybutadiene is 1.516 to
It is 1.520, and generally, the styrene resin has a higher refractive index than the rubber-like polymer. However, there is a strong demand in the market for the transparency of styrene-based resins, and the development of transparent rubber-modified styrene-based resins, that is, maintaining transparency while imparting impact resistance to styrene-based resins, is an extremely important issue in industry. Has become. Especially in the use of transparent rubber-modified styrene-based resin in the field of packaging materials, a method is used in which the resin is primarily processed into a sheet shape, and then vacuum-formed or pressure-formed into a desired shape. Since the problem that the transparency of the resin decreases during the secondary processing occurs, there is a great demand on the market not only for the transparency of the resin itself but also for maintaining the transparency during molding.

Further, in recent years, a resin which can be easily recycled (material recycling) has been demanded due to the heightened awareness of environmental problems. In terms of productivity, for example, when secondary processing a resin sheet into a blister case, it is better to reuse the remaining resin after punching the processed product as the molding material for higher productivity It is important to develop an easy resin. To recycle the resin, the processed resin is crushed, heated by an extruder or the like, melted, kneaded, and then used again as a material, but the conventional transparent rubber-modified styrene resin is repeatedly heated. When added, there is a problem that the hue of the resin changes and the impact resistance decreases. Therefore, how to prevent the deterioration of the physical properties of the resin, especially the hue and impact resistance due to heat history, is an important issue in the development of transparent rubber-modified styrene resin.

Examples of conventional transparent rubber-modified styrene resin include polystyrene which is a styrene resin and styrene-butadiene block copolymer which is a rubber-like polymer as disclosed in JP-A-57-195139. Manufactured by blending. However, in the product by this blend, the method of blending polystyrene and styrene-butadiene block copolymer is changed (for example, even if the same material is used, the extruder type for blending is changed from a single-screw type to a twin-screw type). If the same material or the same extruder is used, the extrusion temperature, residence time, rotation speed, etc. will be changed) and the kneading state of the two materials, heat deterioration, and the degree of discoloration will change, and both transparency and impact resistance will increase. Change and there is a problem in reproducibility, depending on the extrusion conditions, the rubber-like polymer gels and becomes a big problem in molding processing such as generation of fish eyes. Furthermore, since the refractive indexes of both are originally different, the product Since transparency is naturally limited, it cannot fully meet the market demand. From the viewpoint of recycling of the resin, it is not preferable because deterioration of the resin progresses remarkably as the heat history increases and the impact resistance decreases. In order to improve transparency, there is a method of increasing the styrene content in the styrene-butadiene block copolymer to reduce the difference in the refractive index with polystyrene, but the copolymer has properties similar to polystyrene. And the physical properties of the product, especially the impact resistance, are significantly deteriorated, which is not preferable.

In order to solve the above-mentioned problems, for example, in JP-A-4-351649, it is obtained by copolymerizing one or more kinds of acrylic acid alkyl ester or methacrylic acid alkyl ester with a styrene monomer. A method of blending a styrenic copolymer having a refractive index similar to that of the rubber-like polymer with the rubber-like polymer is disclosed. According to this method, the styrene-based copolymer and the rubber-like polymer have substantially the same refractive index, so the transparency is improved to some extent, but the impact resistance, and further the impact resistance after thermal history, is improved. As a result, the problem due to the blending method has not been improved at all. That is, the impact resistance is low, and further, the impact resistance greatly changes depending on the degree of kneading, and the impact resistance decreases as the heat history increases, which is not preferable.

Therefore, as disclosed in, for example, Japanese Patent Publication No. 62-434507, a transparent rubber is obtained by emulsion-polymerizing a styrene monomer and a (meth) acrylic acid alkyl ester in a specific ratio in the presence of a rubber-like polymer latex. There is a method for producing a modified styrene resin. In addition, JP-A-4-22484
8, a graft polymer obtained by polymerizing a styrene monomer and a (meth) acrylic acid alkyl ester on a rubbery polymer by an emulsion polymerization method, and a styrene monomer produced by bulk or solution polymerization There is a method of producing a transparent rubber-modified styrene-based resin by blending a (meth) acrylic acid alkyl ester copolymer with an extruder or the like. However, the resins produced according to these methods contain impurities such as emulsifiers and coagulants, and due to these impurities, the transparency of the resin is low and the hue changes after heat history are large. When this resin is molded and processed, impurities remain in the mold and discolor, and eventually it is transferred to the resin, causing defective molding. Further, if the vent portion of the mold is clogged with impurities, the gas cannot escape from the mold, and the resin cannot be uniformly filled in the mold, resulting in a molding defect.

Japanese Patent Publication No. 55-25215 discloses a method for producing a transparent rubber-modified styrenic resin by dissolving a rubber-like polymer in a monomer consisting of styrene and methyl methacrylate, and then batchwise bulk polymerization. There is. The rubber-like polymer is a substance which has the ability to react with radicals and exhibits a rubber-like shape at room temperature, and polybutadiene, a butadiene-styrene random copolymer, a butadiene-styrene block copolymer and the like are used. Since this method does not contain an emulsifying agent or the like which is a problem in the production of a resin by emulsion polymerization or bulk-suspension polymerization, the above-mentioned problems due to impurities do not occur, but according to the patent publication, the diameter of the rubber-like polymer particles produced Is as large as 4 to 7 μm, and since the surface of the molded product is rough, light is scattered and the transparency is low. In addition, the molding process also causes a decrease in transparency. The impact resistance of the resin after heat history is significantly lower than before heat history,
There is also a problem that the hue changes greatly.

In order to improve the above problems, for example, Japanese Patent Publication No. 63-31488 discloses a method for producing a transparent rubber-modified styrene resin by continuous flow bulk polymerization. That is, a polymerization raw material in which a rubbery polymer is dissolved in a monomer containing methyl methacrylate as a main component is continuously supplied to a single reaction tank, and the temperature is 161 ° C. while continuously stirring the solution. 195 ° C, pressure 100-175 psig
In addition, it is a method for producing a transparent rubber-modified styrenic resin by performing polymerization while controlling the average residence time to be less than 90 minutes. As the rubber-like polymer, polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, ethylene-propylene-diene copolymer, isoprene polymer and copolymer are used. However, in order to produce a resin based on this method, it is necessary to control polymerization conditions such as polymerization temperature, reaction pressure, and average residence time extremely strictly, while the polymerization temperature is 161 ° C to 19 ° C.
Since the temperature is as high as 5 ° C, the polymerization reaction tends to run away easily, and it is difficult to maintain the polymerization conditions constant for a long period of time. Therefore, in order to operate as an actual plant, there is a big problem in the operational stability of the plant, and further in the ability to stably produce a resin having a high degree of transparency and impact resistance. In addition, the production cost is high because a great deal of labor is required to control the polymerization conditions. Further, since the polymerization temperature is high, many low-molecular weight copolymers are produced, and like the impurities contained in the resin produced by the emulsion or suspension polymerization described above, the transparency of the resin is reduced during the molding process, and the discoloration, It causes defective molding.

Another method for producing a transparent rubber-modified styrenic resin by continuous flow bulk polymerization is, for example, Japanese Patent Publication No.
-54484, a rubbery polymer, a styrene-based monomer,
A first stream in which a solution containing an alkyl (meth) acrylate and a solvent is polymerized and stopped until the polymerization conversion rate at which the rubber-like polymer becomes particles is not exceeded, a styrene-based monomer, ( A transparent rubber-modified styrenic resin, characterized in that a solution comprising a (meth) acrylic acid alkyl ester and a solvent is mixed with a second stream in the course of polymerization, and the rubber-like polymer is made into particles by the subsequent polymerization. A method of manufacturing is disclosed. As the rubber-like polymer, one kind or a mixture of two or more kinds selected from polybutadiene and butadiene-styrene copolymer is used. In this method, a considerable amount of polymerization is performed in each of the multiple reactors, but since the mixing ratio of the unreacted styrene-based monomer and the (meth) acrylic acid alkyl ester is different in each reactor, the styrene-based monomer produced is different. There is a problem in that the composition distribution of the monomer- (meth) acrylic acid alkyl ester copolymer tends to be wide, and strict control of polymerization conditions is required to ensure transparency. Further, no consideration is given to the retention of hue and impact resistance after thermal history.

In Japanese Patent Laid-Open No. 6-145443, a styrene-based resin composition in which a decrease in transparency is small in a molding process in which a rubber-modified styrene-based polymer, a styrene-butadiene block copolymer and a terpene-based resin are mixed, particularly in a secondary process The thing is disclosed. In this method, since the styrene-butadiene block copolymer and the terpene resin are added, the production cost of the resin composition is high, and the change in hue after thermal history has not been improved. In addition, impact resistance decreases as heat history increases, which is not preferable.

In Japanese Patent Laid-Open No. 4-180907, in the presence of a styrene-butadiene copolymer rubber in which the proportion of 1,2-vinyl bonds among the unsaturated bonds based on butadiene is 14 to 25%, a plurality of rubbers having no moving parts are disclosed. In a continuous bulk polymerization device incorporating a tubular reactor in which the mixing element is fixed, the styrene monomer and the (meth) acrylic acid alkyl ester are copolymerized while the polymerization liquid is statically mixed. The manufacturing method is shown. In this method, it is necessary to control the polymerization conversion rate for each of a plurality of complicated reactors according to the number of reactors, and there is a problem in controllability of polymerization and productivity at that time. Further, regarding the retention of impact resistance after thermal history, the impact resistance decreases as the thermal history increases, which is not preferable.

In order to obtain a transparent rubber-modified styrenic resin having high impact resistance as described above, emulsion polymerization, bulk-suspension polymerization to batch-type bulk or solution polymerization, continuous flow-type bulk or solution polymerization are used in the prior art. Although the transition of the manufacturing method to
A rubber-modified styrene-based resin composition and a method for producing the same that have simultaneously achieved the development of impact resistance, the deterioration of transparency during molding processing, the change of hue due to heat history, and the prevention of reduction in impact resistance have been developed. It has not been.

[0014]

The object of the present invention is to provide a transparent rubber-modified styrenic resin composition by continuous flow type bulk or solution polymerization, and a method for producing the same, that is, excellent transparency and impact resistance, and particularly molding process. A rubber-modified styrenic resin composition that realizes retention of transparency at the time and retention of hue and impact resistance after heat history, and a method for producing the same.

[0015]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, in a method for producing a rubber-modified styrene resin by a continuous flow type bulk or solution polymerization method, a specific structure Of a styrene- (meth) acrylate having a refractive index substantially equal to that of the rubber-like polymer by polymerizing a styrene-based monomer and an alkyl (meth) acrylate under a specific condition. )
After forming the acrylic acid alkyl ester copolymer, the rubbery polymer is transferred to particles dispersed in the continuous phase composed of the copolymer, and then unreacted monomers are removed under specific conditions. As a result, the rubber-modified styrenic resin composition produced had a high degree of transparency and impact resistance, but there was little decrease in transparency during molding, and even if heat history was repeated, the hue change and impact resistance The present invention has been completed based on the surprising fact that the deterioration is unlikely to occur.

That is, the present invention comprises 5 to 50% by weight of styrene and 50 to 95% by weight of butadiene, and the ratio of 1,2-vinyl bonds among unsaturated bonds based on butadiene is 1.0 to 13.8% by weight. %, A rubber-like polymer containing 4 to 30 parts by weight of a styrene-butadiene copolymer (A) having a viscosity of a 5% by weight styrene solution in the range of 3 to 60 centipoise at 25 ° C. of 70% by weight or more, Styrene- (meth) acrylic acid alkyl ester having a refractive index substantially equal to that of a rubber-like polymer and comprising 20 to 70% by weight of styrene monomer and 30 to 80% by weight of (meth) acrylic acid alkyl ester. Copolymer 70 to 96 parts by weight, and the rubbery polymer is dispersed in the styrene- (meth) acrylic acid alkyl ester copolymer to give an average particle diameter of 0.1 to 2.0. m, the particle diameter distribution index of 2.0 to 5.0
The present invention provides a transparent rubber-modified styrene-based resin composition which is a particle of the above, and a method for producing the same.

The manufacturing method of the present invention will be described in detail below.

The feature of the present invention is to use a rubber-like polymer having a specific molecular structure. In the present invention, 70% by weight or more, preferably 85% by weight of the rubber-like polymer dissolved in the styrenic monomer and the (meth) acrylic acid alkyl ester.
5% to 50% by weight of styrene and 5% of butadiene
0 to 95% by weight, and the ratio of 1,2-vinyl bonds among the unsaturated bonds based on butadiene is 1.0 to 13.
The styrene-butadiene copolymer (A) has a viscosity of a 8% by weight, 5% by weight styrene solution at 25 ° C. within the range of 3 to 60 centipoise. The rubber-like polymer (B) other than the copolymer (A) contained in the rubber-like polymer is not particularly limited, and examples thereof include commercially available polybutadiene, styrene-butadiene copolymer, and ethylene-propylene copolymer. A united product or a product obtained by hydrogenating these may be used alone or in combination of two or more. The resin using polybutadiene as the rubber-like polymer (B) has excellent impact resistance, the resin using styrene-butadiene copolymer has excellent moldability, ethylene-propylene copolymer, hydrogenated rubber-like polymer The resin using the coalescence has excellent weather resistance. When the proportion of the copolymer (A) in the rubber-like polymer is less than 70% by weight, a large number of rubber-like polymer particles having a particle size of more than 2 μm are produced regardless of the polymerization conditions, and the transparency of the resin is impaired. It is not preferable. When the proportion of the copolymer (A) in the rubber-like polymer is 85% by weight or more, the transparency of the resin is particularly high, and the transparency is less likely to decrease during molding.

The styrene-butadiene copolymer (A) used in the present invention comprises 5 to 50% by weight of styrene and 50% of butadiene.
˜95% by weight. The ratio of styrene is 5 to 3
The resin using 0% by weight of the rubbery polymer has excellent impact resistance, and the resin using the rubbery polymer having a styrene content of 30 to 50% by weight has excellent transparency. The ratio of styrene is 15
When the rubbery polymer is used in an amount of up to 35% by weight, a resin having a high balance of transparency and impact resistance can be obtained. The resin using the rubber-like polymer in which the proportion of styrene is 20 to 40% by weight has little change in hue due to heat history. When the proportion of styrene is less than 5% by weight, the diameter of rubber particles produced is remarkably large and the transparency of the resin is low, which is not preferable. The ratio of styrene is 5
If it exceeds 0% by weight, the impact resistance of the resin becomes low, which is not preferable. The styrene-butadiene copolymer (A) used in the present invention may be a random copolymer of styrene and butadiene, or a block copolymer composed of polystyrene and polybutadiene, but particularly from the viewpoint of controllability of particle diameter. Block copolymers are preferred. In the case of the block copolymer, the polystyrene part and the polybutadiene part may be bonded by a styrene-butadiene random copolymer.

In the present invention, the ratio of 1,2-vinyl bonds among the unsaturated bonds based on butadiene contained in the styrene-butadiene copolymer (A) is 1.0 to 13.8.
It is within the range of weight%. In the prior art, for example, as shown in JP-A-4-180907, when a styrene-butadiene copolymer having a 1,2-vinyl bond ratio of less than 14% by weight is used, a rubber-modified styrene resin is used. It was thought that it would not be possible to obtain those with excellent impact resistance. However, according to a study by the present inventors, a styrene-based resin using a styrene-butadiene copolymer having a 1,2-vinyl bond ratio of less than 14% by weight has a 1,2-vinyl bond ratio of 14% by weight. It has the same impact resistance as the styrene-based resin (C) using the styrene-butadiene copolymer described above, and also has a decrease in transparency during molding, a change in hue when heat history is accumulated on the resin, and resistance to heat. It has acquired a surprising characteristic that impact resistance is less likely to occur than the resin (C), which is not present in conventional resins. Particularly, a resin using a rubbery polymer having a 1,2-vinyl bond ratio of 4 to 12% by weight has high transparency, and a resin using a rubbery polymer of 9 to 13.8% by weight has impact resistance. The resin containing 1 to 10% of rubber-like polymer has a small change in hue due to heat history,
The resin using 1% of the rubber-like polymer is less likely to deteriorate the impact resistance due to the heat history, and the resin containing 7 to 12% by weight of the rubber-like polymer does not lower the transparency at the time of molding. preferable. The microstructure of the rubber-like polymer depends on the type of catalyst system used for producing the rubber-like polymer, the composition of the catalyst, additives,
It depends on factors such as reaction temperature. Therefore, the ratio of 1,2-vinyl bonds among the unsaturated bonds based on butadiene contained in the rubber-like polymer can be achieved at a desired ratio by appropriately controlling the above factors. The reason why the physical properties of the resin are improved by using the copolymer (A) in which the ratio of 1,2-vinyl bonds among unsaturated bonds based on butadiene is within a specific range is not clear, but it is a rubber-like polymer. It is surmised that the interaction between the 1,2-vinyl bond sites of the above or the 1,2-vinyl bond sites of the rubber-like polymer and the styrene- (meth) acrylic acid alkyl ester copolymer exerts some influence. .

The viscosity of a 5% by weight styrene solution of the styrene-butadiene copolymer (A) used in the present invention at 25 ° C. is 3 to 60 centipoise. When the solution viscosity is lower than 3 centipoise, the impact resistance of the resin becomes low, which is not preferable. When the viscosity of the solution is higher than 60 centipoise, the diameter of the rubber-like polymer particles formed is significantly increased and the transparency of the resin is lowered, which is not preferable. In particular, a resin using a rubber-like polymer having a solution viscosity of 3 to 30 centipoise is excellent in transparency, and a rubber-like polymer having a solution viscosity of 10 to 60 centipoise is excellent in impact absorbing ability of the rubber-like polymer particles. A resin using a rubber-like polymer having a solution viscosity of 3 to 40 centipoise, preferably 7 to 30 centipoise, and particularly preferably 7 to 20 centipoise has an excellent balance between transparency and impact resistance. The solution viscosity is 3 to 2
A resin using a rubbery polymer of 5 centipoise is less likely to change in hue due to heat history, and a resin using a rubbery polymer having a solution viscosity of 10 to 40 centipoise is less likely to reduce impact resistance due to heat history, which is preferable. .

In the present invention, when the viscosity of a 5% by weight styrene solution of the styrene-butadiene copolymer (A) at 25 ° C. is 3 to 40 centipoise, particularly 3 to 30 centipoise or 3 to 20 centipoise, the copolymerization The number average molecular weight (M) of the weight average molecular weight (Mw) of the combination (A)
The ratio (Mw / Mn) with respect to n) is preferably 1 to 1.5 or less, and particularly preferably 1 to 1.3 or less from the viewpoint of maintaining the transparency of the resin and the transparency during molding. Generally, a styrene-butadiene block copolymer is usually produced by a living polymerization method and therefore has a narrow molecular weight distribution. However, the viscosity of a 5% by weight styrene solution at 25 ° C is 3-40, especially 3
If it is lowered to about 30 to 30 centipoise or about 3 to 20 centipoise, the produced rubber-like polymer mass undergoes large deformation called cold flow during storage and transportation at room temperature, which makes it difficult to handle industrially. It is considered not suitable for. Therefore, to prevent cold flow of rubbery polymers with low solution viscosity, improve the catalyst system, adjust the polymerization rate, divide the polymerization process, and add a coupling agent such as tin or zinc to broaden the molecular weight distribution and to make it cold. Many correspond to the flow. When Mw / Mn is more than 1.5, the particle size generated is large when the polymerization conversion rate when the rubbery polymer is made into particles is high, and the particle size fluctuates greatly due to a slight fluctuation in the polymerization conversion rate. However, it is not preferable because it is difficult to stably generate the same particle size. The weight average molecular weight (M
w) and the number average molecular weight (Mn) are measured by using a gel permeation chromatograph, and are values converted by comparison with a polystyrene standard sample whose molecular weight is already known.

The rubber-like polymer is used in an amount of 2 to 12 parts by weight, preferably 3 to 10 parts by weight, based on 100 parts by weight of the polymerization raw material. When the rubber-like polymer exceeds 12 parts by weight, it is difficult to form the rubber-like polymer particles in the reactor. If the amount of the rubber-like polymer is less than 2 parts by weight, the impact resistance of the resin is low, which is not preferable. The amount of the rubber-like polymer contained in 100 parts by weight of the produced resin is preferably 4 to 30 parts by weight.
When the amount of the rubbery polymer is 4 to 15 parts by weight, the transparency of the resin is excellent, and when the amount of the rubbery polymer is 10 to 30 parts by weight, the impact resistance of the resin is excellent. The amount of rubbery polymer is 6 to 20
In the case of parts by weight, the balance of impact resistance and transparency of the resin is excellent. If the amount of the rubber-like polymer exceeds 30 parts by weight, the transparency of the resin will be significantly reduced, which is not preferable. If the amount of the rubber-like polymer is less than 4 parts by weight, the impact resistance of the resin is low, which is not preferable.

The transparent rubber-modified styrenic resin composition of the present invention can be produced by blending the individually prepared rubber-like polymer and a styrene- (meth) acrylic acid alkyl ester copolymer, and the rubber. In the presence of a polymer
There is a method of emulsion polymerization, bulk polymerization or solution polymerization of styrene monomer and (meth) acrylic acid alkyl ester continuously or batchwise, but the continuous flow method is used because of low impurities and high transparency. Bulk or solution polymerization methods are preferred.

The styrenic monomer in the present invention has the general formula (I)

[0026]

Embedded image (In the above formula, R ¹ represents hydrogen, an alkyl group having 1 to 5 carbon atoms, halogen, R ² represents hydrogen, an alkyl group having 1 to 5 carbon atoms, halogen, an unsaturated hydrocarbon having 1 to 5 carbon atoms, R ² may be the same or different), and an unsaturated aromatic compound represented by the formula ( ² ) may be used, particularly styrene and derivatives thereof, such as styrene, α-methylstyrene, o
-Methylstyrene, m-methylstyrene, p-methylstyrene, α-methyl-p-methylstyrene, halogenated styrene, ethylstyrene, p-isopropylstyrene, pt-butylstyrene, 2,4-dimethylstyrene, divinyl. One or more of benzene and the like are used, and preferably styrene, α-methylstyrene, p-
Methylstyrene is used. You may use these individually or in mixture of 2 or more types. Styrene is the most versatile and inexpensive, and the use of α-methylstyrene or p-methylstyrene improves the heat resistance of the resin. The styrene-based monomer is usually in the range of 20 to 70 parts by weight, preferably 25 to 5 parts by weight, based on 100 parts by weight of the total amount of various monomers in the polymerization raw material.
Used in the range of 5 parts by weight.

The (meth) acrylic acid alkyl ester in the present invention has the general formula (II)

[0028]

Embedded image (In the above formula, R ³ represents hydrogen or an alkyl group having 1 to 5 carbon atoms, and R ⁴ represents an alkyl group having 1 to 5 carbon atoms), and a rubber-like compound described below. A compound having a lower refractive index than that of the compound is used, preferably methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate is used, and particularly preferably methyl methacrylate or ethyl acrylate is used. You may use these individually or in mixture of 2 or more types. The resin using methyl methacrylate has improved rigidity and weather resistance, and the resin using butyl acrylate has improved flexibility. When ethyl acrylate is used, the flexibility of the resin is improved, and at the same time, the impact resistance of the resin is high because it is easy to control the rubber particle size. The (meth) acrylic acid alkyl ester is used in the range of usually 30 to 80 parts by weight, preferably 45 to 75 parts by weight, based on 100 parts by weight of the total amount of various monomers in the polymerization raw material.

In the present invention, benzoyl peroxide, lauroyl peroxide, t
-Butyl peroxypivalate, t-butyl peroxybenzoate, t-butyl peroxyisobutyrate,
t-butylperoxy (2-ethylhexanoate),
t-butyl peroxy octoate, cumyl peroxy octoate, 1,1-bis (t-butyl peroxy)
Organic peroxides such as 3,3,5-trimethylcyclohexane, 2,2-azobisisobutyronitrile, 2,2-
Azo compounds such as azobis (2-methylbutyronitrile) and 2,2-azobis (2,4-dimethylvaleronitrile) are used. The use of organic peroxide is preferred because of its high grafting efficiency. The type of polymerization initiator used is the polymerization temperature, the average residence time of the polymerization liquid, the target polymerization conversion rate,
It can be selected based on the half-life of the polymerization initiator.
For example, when the polymerization is performed at 80 to 100 ° C., a polymerization initiator having a half-life at 90 ° C. of 1 minute to 2 hours is added to 100 to 1
When performed at 40 ° C, the half-life at 90 ° C is 10 minutes to
When carrying out the polymerization initiator for 20 hours at 140 to 160 ° C., it is preferable to use the polymerization initiator having a half-life at 90 ° C. of 2 hours or more. t-butylperoxypivalate, t-butylperoxy (2-ethylhexanoate), 1,1-bis (t-butylperoxy) 3,3
The use of 5-trimethylcyclohexane is preferred, especially t-butylperoxy (2-ethylhexanoate),
The use of 1,1-bis (t-butylperoxy) 3,3,5-trimethylcyclohexane is preferred. The polymerization initiator is usually 0.001 to 5.0 parts by weight, preferably 0.001 to 100 parts by weight based on 100 parts by weight of the total amount of monomers in the polymerization raw material.
It is used in an amount of 3.5 parts by weight, preferably 0.001 to 2.0 parts by weight. If the amount of the polymerization initiator exceeds 5.0 parts by weight, the decomposition product of the unreacted polymerization initiator accumulates in the polymerization system and inhibits the polymerization, which is not preferable. When the amount of the polymerization initiator is less than 0.001 part by weight, the polymerization temperature becomes high, and the polymerization reaction tends to run away, which is not preferable.

In the present invention, an organic solvent may be added to the polymerization raw material, if necessary. Examples of the organic solvent include benzene, toluene, xylene, ethylbenzene, acetone, isopropylbenzene, methylethylketone, and dimethylformamide, and the use of ethylbenzene and toluene is particularly preferable. The organic solvent concentration is usually 5 to 50 parts by weight, preferably 5 to 30 parts by weight, based on 100 parts by weight of the total polymerization liquid.

In the present invention, various known chain transfer agents can be used to control the molecular weight of the styrene- (meth) acrylic acid alkyl ester copolymer.
For example, known chemical substances such as t-dodecyl mercaptan, n-dodecyl mercaptan, n-octyl mercaptan and α-methylstyrene dimer are used. The amount of the chain transfer agent used depends on its chain transfer ability and the target molecular weight of the copolymer, but is usually in the range of 0 to 10 parts by weight based on 100 parts by weight of the total amount of various monomers in the polymerization raw material. Used in.

The polymerization apparatus in the present invention is not particularly limited, and any type of reactor such as a tank reactor, a tubular reactor, a tower reactor can be used. The number of reactors constituting the polymerization apparatus is preferably 1 or more, and particularly preferably 1 from the viewpoint of uniformity and controllability of the styrene- (meth) acrylic acid alkyl ester copolymer composition. As a system for removing the heat of polymerization in the reactor, a system in which a heating medium is passed through a jacket or draft tube to remove heat is used, and low boiling point components such as monomers and organic solvents are evaporated from the polymerization liquid to produce the polymerization liquid by latent heat of vaporization. Those that incorporate a cooling system are preferred. The reactor is equipped with well-known stirring blades such as paddle blades, turbine blades, lattice blades, gate blades, propeller blades, screw blades, Fowler blades, and helical ribbon blades, and these blades may be used alone or in combination of two or more. Can also be used in combination. Further, the configuration of the blade may be a single-stage blade or a multistage blade. As a reactor for transferring the rubber-like polymer into particles, a complete mixing type reaction tank is particularly preferable because of the ease of controlling the diameter of the rubber-like polymer particles produced and the high ability to uniformly mix the polymerization liquid. The rotation speed of the stirring blade varies depending on the volume of the reactor, the viscosity of the polymerization solution, the required shearing force, etc., but is usually 3 rpm to 600 rpm.

In the present invention, the polymerization is usually carried out at 80 to 160 ° C.,
It is preferably carried out in the range of 100 to 140 ° C. When the polymerization temperature is lower than 80 ° C., the polymerization rate is low and the productivity is poor, and the heat load necessary for volatilizing the unreacted monomer and the organic solvent in the subsequent devolatilization apparatus is unfavorable. Further, at 160 ° C or higher, the polymerization reaction is likely to run away, and it is difficult to maintain the polymerization conditions for a long time.
In order to operate as an actual plant, there is a big problem in the operational stability of the plant, and further, in the ability to stably produce a resin having a high degree of transparency and impact resistance. Further, when the polymerization temperature is 160 ° C. or higher, a large amount of a low molecular weight copolymer is produced, which deteriorates the moldability of the product, which is not preferable.

The average residence time of the polymerization liquid in the reaction tank of the present invention is 0.2 to 10.0 hours, preferably 1.5 to 5.0 hours. When the average residence time is shorter than 0.2 hours, the phenomenon of passing through the reaction tank without polymerization of the polymerization raw material occurs and the physical properties of the product deteriorate, and when the average residence time is longer than 10.0 hours, the production amount. Is decreased, the manufacturing cost of the resin is increased, and the productivity is decreased, which is not preferable.

In the present invention, the solid content in the polymerization solution is 1
Particle size of 0 to 60% by weight or less, preferably 15 to 50% by weight or less, in which a rubber-like polymer is dispersed in a continuous phase composed of a styrene- (meth) acrylic acid alkyl ester copolymer .1 to 2.0 μm and a particle size distribution index of 2.0 to 5.0. The solid content in the polymerization solution means the sum of the rubber-like polymer and the styrene- (meth) acrylic acid alkyl ester copolymer contained in the polymerization solution. The main factor for the rubbery polymer to transfer to the dispersed phase is the weight ratio of the rubbery polymer and the styrene- (meth) acrylic acid alkyl ester copolymer produced, and the amount of the copolymer is A phase transition occurs when the amount exceeds about 2 times the amount of the rubber-like polymer, but in the present invention, the polymerization liquid is controlled under the above-mentioned specific rubber-like polymer molecular structure, rubber-like polymer concentration, amount of polymerization initiator and polymerization temperature. It has been found that the particle size and particle size distribution of the rubber-like polymer after phase transition can be controlled within a predetermined range by setting the solid content in the state to 10 to 60% by weight or less. If the solid content in the polymerization liquid is less than 10% by weight or exceeds 60% by weight, the particle size and particle size distribution of the rubber-like polymer become remarkably large and the transparency and impact resistance of the resin deteriorate, which is not preferable. Solid content in the polymerization liquid is 50
The phase transition in the state of not more than wt% improves the transparency of the resin, particularly the retention of transparency during molding, which is preferable.

The average particle size of the rubber-like polymer particles contained in the rubber-modified styrenic resin in the present invention is 0.1-2.
0 μm, the particle size distribution index is 2.0 to 5.0. The method for measuring the rubber-like polymer particle size and particle size distribution index is described in Example 1. If the particle size is smaller than 0.1 μm, the impact resistance of the resin is low, and if it is larger than 2.0 μm, both transparency and impact resistance are low, which is not preferable. In particular, the average particle size is 0.
Resin of 1 to 1.0 μm is excellent in transparency and 0.4 to 2.0
The resin of μm has excellent impact resistance, and the resin of 0.2 to 1.3 μm, preferably 0.3 to 0.8 μm has excellent balance of transparency and impact resistance. If the particle size distribution index is smaller than 2.0, the impact resistance of the resin is low, and if it is larger than 5.0, the transparency of the resin is low, which is not preferable. Particularly, a resin having a particle size distribution index of 2.0 to 4.0, preferably 2.0 to 3.0 is excellent in transparency and retention of transparency during molding,
The resin of 5.0, preferably 2.5 to 4.0 has excellent impact resistance, and the resin of 2.2 to 3.5 has excellent balance of transparency and impact resistance.

The polymerization liquid continuously withdrawn from the reaction tank is, for example, Japanese Patent Publication No. 48-29798 and Japanese Patent Laid-Open No. 61-22.
8012, JP-A-62-179508, JP-B-3-56
242 and the like are continuously supplied to a devolatilization apparatus to remove volatile substances such as unreacted monomers and organic solvents from the polymerization liquid. At this time, the solid content in the polymerization solution is 2
It is 0 to 75% by weight, preferably 20 to 60% by weight.
When the solid content is less than 20% by weight, the amount of heat for evaporating the volatile substance is large and the productivity is low, which is not preferable. When the solid content exceeds 75% by weight, the viscosity of the polymerization liquid is high and the operation of the devolatilization device becomes difficult, which is not preferable.

The production step following the devolatilization step is not particularly limited, but the extrusion step, the additive supply step, the production step which are usually carried out in the continuous flow type bulk or solution polymerization method for producing a styrene resin. A transparent styrene resin composition is manufactured through the granulating process.

The transparent styrenic resin composition obtained by the present invention has excellent transparency, impact resistance and molding processability, and is a sheet / packaging material for IC cases, blister cases, etc .; washing machines, air conditioners, refrigerators. , Home appliances such as AV equipment; general machines such as office automation equipment, telephones, musical instruments; miscellaneous goods such as toys and cosmetic containers; structural materials for automobiles, housing materials, etc., and their industrial utility value is extremely high.

[0040]

The present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

The analysis and physical property evaluation of the styrene resin composition were carried out by the following methods. (A) Average particle size and particle size distribution index of rubber-like polymer: An ultrathin section of a resin composition dyed with osmic acid was photographed with a transmission electron microscope, and the rubber-like polymer particles 50 in the photograph were taken.
The average particle diameter is obtained by measuring the particle diameters of 0 to 700 particles and averaging them according to the following equation (Equation 1). However, n is the number of rubber-like polymer particles having a particle diameter D.

[0042]

[Equation 1] Average particle size of rubber-like polymer = ΣnD ⁴ / ΣnD ³ I Further, the particle size distribution index is the particle size when the cumulative volume fraction of the particle sizes from the larger particle size is 10%. Where DA is DA and the particle diameter when the cumulative volume fraction of the particle diameters from the larger particle diameter is 90% is DB, it is an index represented by the following equation (Equation 2).

[0043]

## EQU00002 ## Particle size distribution index of rubber-like polymer = DA / DB II (b) Preparation of test piece: The obtained resin composition was molded at a molding temperature of 2.
Injection molding was performed at 40 ° C. and a mold temperature of 50 ° C., and test pieces for measuring haze and hue (length 15 cm × width 10 cm × thickness 2.
5 mm) and a test piece for practical impact strength measurement having the shape shown in FIG. (C) Haze: Measured according to ASTM-D1003. The smaller the haze value, the better the transparency. (D) Practical impact strength: A drop weight impact strength test was performed on three sites (site S, site T, site U) of the test piece having the shape shown in FIG. The tip of the falling weight was R = 6.4 mm, and the inner diameter of the loading platform was 25 mm. The falling weight impact strength is 5 of the test piece.
0% is the energy at the time of destruction, and is represented by the value obtained by multiplying the weight of the falling weight and the fall distance of the falling weight. In FIG. 1, the gate portion, that is, the inlet where the molten resin flows into the mold is G
The site S is a site where the thickness changes due to the position of the gate part, the site T is a site near the corner, and the site U is a standard site. Generally, the impact strength tends to increase in the order of the part S, the part T, and the part U. (E) Change in transparency during molding: The resin was primarily processed into a sheet having a thickness of 0.3 mm using a 30 mm sheet extruder. This sheet is vacuum formed by 15 cm in length x 10 in width
Fabricated into a food package of cm x 5 cm deep. The side surface of this food package was cut out and the haze (H) was measured, and the ratio (H / H) of the original sheet to the haze (h) was measured.
h) were compared. A resin whose H / h value is close to 1 is excellent in maintaining transparency during molding. (F) Hue: A test piece was prepared before and after the thermal history of the resin, and the Lab-based color difference was measured according to JIS-K7105. The smaller the color difference value is, the better the resin is.

Example 1 A styrene resin was produced using a continuous polymerization apparatus consisting of one complete mixing type reaction vessel having a capacity of 20 liters. Styrene was used as the styrene-based monomer, and a mixture of methyl methacrylate and ethyl acrylate was used as the (meth) acrylic acid alkyl ester. The rubbery polymer is composed of 25% by weight of styrene and 75% by weight of butadiene, and the proportion of 1,2-vinyl bonds among the unsaturated bonds based on butadiene is 10% by weight, and 5% by weight at 25 ° C.
A styrene-butadiene block copolymer having a styrene solution viscosity of 12 centipoise and Mw / Mn of 1.1 was used. The copolymer was prepared by a solution polymerization method using a lithium catalyst. Further, as a polymerization initiator, t-
Butyl peroxy (2-ethylhexanoate) was used. Styrene 30 parts by weight, methyl methacrylate 36 parts by weight, ethyl acrylate 9 parts by weight, ethylbenzene 20 parts by weight, rubber polymer 5 parts by weight, t-dodecyl mercaptan 0.07 parts by weight, polymerization initiator 0.03 parts by weight. Polymerization raw material consisting of 10 kg / h is continuously supplied to the reaction vessel using a plunger pump to carry out the polymerization, and the polymerization temperature is adjusted so that the solid content at the outlet of the reaction vessel is 4
The polymerization conversion rate was 7.0% by weight and the polymerization conversion rate was 56.0% by weight. The polymerization temperature at this time was 137 ° C. The stirring speed of the reaction tank was 150 rpm, and the polymerization temperature was at the top of the reaction tank.
When the thermocouple was put into the three places of the middle part and the lower part and it measured,
The temperatures at the three locations are controlled within the range of an average value ± 0.2 ° C, and it is considered that the polymerization liquid is uniformly mixed. The proportions of styrene, methyl methacrylate and ethyl acrylate in the polymerization raw materials are 40% by weight, 48% by weight and 12% by weight, respectively. Following polymerization, the polymerization liquid continuously withdrawn from the reaction tank is supplied to a devolatilization device to separate volatile substances such as unreacted monomers and organic solvents, and then the resin is passed through an extruder. Pelletized. In this experiment, the solid content at the time of phase inversion and before devolatilization was 47% with respect to the polymerization liquid.

Table 1 shows the results of analysis and evaluation of physical properties of the obtained styrene resin. Compared with Comparative Example 1 described below, the change in transparency during molding is small, and even if the ratio of 1,2-vinyl bonds among unsaturated bonds based on butadiene in the rubber-like polymer is less than 14% by weight. It is recognized that the resin has sufficient impact resistance. In order to observe changes in physical properties due to thermal history, the following model experiments were conducted. 40mm single screw extruder (L / D =
30, where L is the length of the full flight screw and D is the diameter of the cylinder) and was heated and melted, cooled with water, solidified again, and pelletized with a pulverizer. The cylinder temperature of the extruder was 220 ° C., the die temperature was 230 ° C., and the screw rotation speed was 100 rpm. Table 1 shows the results of evaluating the physical properties of the styrene resin after repeating this operation 5 times. It can be seen that, as compared with Comparative Example 1 described later, the retention rate of impact resistance is high and the change in hue is small. Among the examples, it is particularly excellent in maintaining transparency during molding.

Comparative Example 1 As a rubbery polymer, 23% by weight of styrene and 77% by weight of butadiene were used, and the proportion of 1,2-vinyl bonds among the unsaturated bonds based on butadiene was 20% by weight. The viscosity of a 5 wt% styrene solution at 11 ° C is 11
A styrene-based resin was manufactured in exactly the same manner as in Example 1 except that a styrene-butadiene block copolymer (manufactured by Nippon Zeon Co., Ltd., trade name NIPOL: NS310S) having a centipoise and Mw / Mn of 1.1 was used. . In this experiment, the solid content at the time of phase inversion and before devolatilization was 47% with respect to the polymerization liquid. The copolymer was prepared by a solution polymerization method using a lithium catalyst. The analysis and physical property evaluation of the obtained styrene resin are shown in Table 1.

Example 2 A styrene resin was produced using a continuous polymerization apparatus in which two complete mixing type reaction tanks used in Example 1 were connected. Styrene was used as the styrene-based monomer, and a mixture of methyl methacrylate and ethyl acrylate was used as the (meth) acrylic acid alkyl ester. The same rubber-like polymer as in Example 1 was used as the rubber-like polymer. Also, 1,1-bis (t-butylperoxy) 3,3,5-as a polymerization initiator
Trimethylcyclohexane was used. Styrene 30 parts by weight, methyl methacrylate 36 parts by weight, ethyl acrylate 9 parts by weight, ethylbenzene 20 parts by weight, rubbery polymer 5
Parts by weight, 0.07 parts by weight of t-dodecyl mercaptan, and 0.03 parts by weight of a polymerization initiator are continuously supplied to the first reaction tank at 10 kg / h using a plunger pump to carry out the polymerization. Then, the polymerization temperature was adjusted so that the solid content at the outlet of the first reaction tank was 23.0% by weight and the polymerization conversion rate was 24.0% by weight based on the polymerization liquid. The polymerization temperature at this time was 110 ° C. The stirring rotation speed of the reaction tank is 150 rpm. The polymerization liquid continuously withdrawn from the first reaction tank is fed to the subsequent second reaction tank to further supply 150 rp.
Polymerization is carried out while stirring at m.
The solid content at the outlet of the reaction tank was 47.0 based on the polymerization liquid.
% By weight, and the polymerization conversion rate was 56.0% by weight. The polymerization temperature at this time was 130 ° C. Then, the polymerization liquid continuously withdrawn from the second reaction tank is supplied to a devolatilization device to separate volatile substances such as unreacted monomers and organic solvents,
The resin was pelletized through the extruder. In this experiment, the solid contents at the time of phase inversion and before devolatilization were 23% and 47% with respect to the polymerization liquid, respectively. Table 1 shows the results of analysis and evaluation of physical properties of the obtained styrene resin. Comparative Example 2 described below
Compared with the above, it can be seen that the change in transparency during molding is small and that it has sufficient impact resistance. It can be seen that the impact resistance is prevented from lowering due to heat history, and the change in hue is small. Among the examples, it is particularly excellent in retaining impact resistance and impact resistance after heat history.

Comparative Example 2 A styrene resin was produced in exactly the same manner as in Example 2 except that the same rubbery polymer as in Comparative Example 1 was used as the rubbery polymer. In this experiment, the solid contents at the phase inversion and before the devolatilization were 26% and 47% of the polymerization liquid, respectively. The analysis and physical property evaluation of the obtained styrene resin are shown in Table 1.

Example 3 A styrene resin was produced using the same continuous polymerization apparatus as in Example 1. Styrene as the styrene monomer,
Methyl methacrylate was used as the (meth) acrylic acid alkyl ester. The same rubber-like polymer as in Example 1 was used as the rubber-like polymer. 1,1-as a polymerization initiator
Bis (t-butylperoxy) 3,3,5-trimethylcyclohexane was used. 27 parts by weight of styrene, 48 parts by weight of methyl methacrylate, 20 parts by weight of ethylbenzene,
5 parts by weight of rubber-like polymer, t-dodecyl mercaptan 0.
A polymerization raw material consisting of 2 parts by weight and 0.03 part by weight of a polymerization initiator is continuously supplied to the reaction tank at 10 kg / h by using a plunger pump to carry out polymerization, and the polymerization temperature is adjusted to exit the reaction tank. The solid content was 47.0% by weight and the polymerization conversion rate was 56.0% by weight based on the polymerization liquid. The polymerization temperature at this time was 141 ° C. The stirring rotation speed of the reaction tank is 15
It is 0 rpm. The proportions of styrene and methyl methacrylate in the polymerization raw materials are 36% by weight and 64% by weight, respectively. After separation of volatile substances from the polymerization liquid following polymerization,
The resin was pelletized through the extruder. In this experiment, the solid content at the time of phase inversion and before devolatilization was 47 with respect to the polymerization liquid.
%Met. Table 1 shows the results of analysis and evaluation of physical properties of the obtained styrene resin. Compared with Comparative Example 3 described later,
It is recognized that the change in transparency during molding is small and that it has sufficient impact resistance. Among the examples, it is particularly excellent in that there is little change in hue due to heat history.

Comparative Example 3 A styrene resin was produced in exactly the same manner as in Example 3 except that the same rubbery polymer as in Comparative Example 1 was used as the rubbery polymer. In this experiment, the solid content at the time of phase inversion and before devolatilization was 47% with respect to the polymerization liquid. The analysis and physical property evaluation of the obtained styrene resin are shown in Table 1.

[0051]

[Table 1]

[0052]

INDUSTRIAL APPLICABILITY The present invention provides a transparent impact-resistant styrene resin composition composed of a rubbery polymer having a specific molecular structure and a styrene- (meth) acrylic acid alkyl ester copolymer, and its production. To provide a way,
The resin composition according to the present invention is excellent in transparency, impact resistance, and particularly impact resistance after heat history, as a sheet / packaging material for IC cases, blister cases, etc .; washing machines, air conditioners, refrigerators, AV equipment, etc. Home appliances; general machines such as office automation equipment, telephones, musical instruments; miscellaneous goods such as toys and cosmetics containers; structural materials such as automobiles and housing materials. .

[Brief description of drawings]

FIG. 1 is a test piece used for evaluation of practical impact strength, (a) is a plan view and (b) is a sectional view.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Masato Takahisa 1-6 Takasago, Takaishi, Osaka Prefecture Mitsui Toatsu Kagaku Co., Ltd. (72) Nao Morita 1-6 Takasago, Takaishi, Osaka Mitsui Toatsu Kagaku Co., Ltd. (72) Inventor Koji Kawano 1-6-6 Takasago, Takaishi-shi, Osaka Mitsui Toatsu Chemical Co., Ltd.

Claims (7)

[Claims] 1. 5 to 50% by weight of styrene and 5 of butadiene
0 to 95% by weight, and the ratio of 1,2-vinyl bonds among the unsaturated bonds based on butadiene is 1.0 to 13.
4 to 30 parts by weight of a rubbery polymer containing 70% by weight or more of a styrene-butadiene copolymer (A) having a viscosity of a 8% by weight, 5% by weight styrene solution at 25 ° C. within a range of 3 to 60 centipoise. , Having a refractive index substantially equal to that of the rubber-like polymer and having a styrene monomer content of 20 to 70% by weight.
And 70 to 96 parts by weight of a styrene- (meth) acrylic acid alkyl ester copolymer consisting of 30 to 80% by weight of (meth) acrylic acid alkyl ester, the rubbery polymer being the styrene- (meth) acrylic. Average particle size of 0.1 to 2.0 dispersed in acid alkyl ester copolymer
A transparent rubber-modified styrene-based resin composition, which is particles having a particle size distribution index of 2.0 to 5.0 μm. 2. The viscosity of a 5% by weight styrene solution of the styrene-butadiene copolymer (A) at 25 ° C. is 3 to 40.
Within the range of centipoise, and the ratio of its weight average molecular weight (Mw) to number average molecular weight (Mn) (Mw /
The transparent rubber-modified styrene resin composition according to claim 1, wherein Mn) is 1.5 or less. 3. A rubber-like polymer is substantially obtained by continuously supplying a polymerization raw material obtained by dissolving a rubber-like polymer in a styrene-based monomer and an alkyl (meth) acrylate to a polymerization apparatus to carry out polymerization. Having the same refractive index
After generating the (meth) acrylic acid alkyl ester copolymer, the rubber-like polymer was transferred to the particles dispersed in the continuous phase composed of the copolymer, and the unreacted monomer was removed from the polymerization solution. (1) 70% by weight or more of the rubbery polymer is 5 to 50% by weight of styrene and 50% of butadiene.
˜95% by weight, and the ratio of 1,2-vinyl bonds among the unsaturated bonds based on butadiene is 1.0 to 13.8.
% By weight, the viscosity of a 5% by weight styrene solution at 25 ° C. is occupied by a styrene-butadiene copolymer (A) having a range of 3 to 60 centipoise, and (2) a rubbery polymer concentration of 2 to 12% by weight. The total amount of the monomer composed of 20 to 70% by weight of the styrene-based monomer and 30 to 80% by weight of the (meth) acrylic acid alkyl ester in the polymerization raw material adjusted to 100
0.001 to 5.0 parts by weight of a polymerization initiator is added to parts by weight, polymerization is performed at a polymerization temperature of 80 to 160 ° C., and a rubber-like substance is obtained in a state where the solid content in the polymerization liquid is 60% by weight or less. The polymer has a particle size of 0.1 to 2.0 μm and a particle size distribution index of 2.0.
To 5.0 particles, and (3) removing unreacted monomer from the polymerization liquid in a state where the solid content in the polymerization liquid is 75% by weight or less, a transparent rubber-modified styrene resin. Continuous manufacturing method. 4. The styrene monomer is styrene,
The continuous transparent rubber-modified styrenic resin according to claim 3, wherein the (meth) acrylic acid alkyl ester is one kind or a mixture of two or more kinds selected from methyl methacrylate, methyl acrylate, ethyl acrylate, and butyl acrylate. Manufacturing method. 5. The styrene-based monomer is styrene,
The continuous method for producing a transparent rubber-modified styrene resin according to claim 3, wherein the (meth) acrylic acid alkyl ester is methyl methacrylate alone or a mixture of methyl methacrylate and ethyl acrylate. 6. The styrene-butadiene copolymer (A) is a block copolymer, and its content at 25 ° C. is 5% by weight.
The viscosity of the styrene solution is in the range of 3 to 40 centipoise, and the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is 1.5 or less. Continuous method for producing a rubber-modified styrene resin. 7. The rubber-like polymer is transferred to dispersed particles in a state where the solid content in the polymerization liquid is 50% by weight or less, and the unreacted unit is reacted from the polymerization solution in the state where the solid content in the polymerization liquid is 60% by weight or less. The method for continuously producing a transparent rubber-modified styrenic resin according to claim 6, wherein the monomer is removed.