JP2001316437A - Manufacturing method of rubber-modified styrenic resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method which gives a rubber-modified styrenic resin having high impact resistance. SOLUTION: In manufacturing a rubber-modified styrenic resin by subjecting a solution comprising 75-98 wt.% of (A) starting material monomers comprising a styrenic monomer or a mixture of a styrenic monomer and a vinyl monomer copolymerizable therewith and (B) 25-2 wt.% of a rubbery polymer, a solution containing a part of the component (A) together with the component (B) is subjected to polymerization until rubber phase inversion occurs and subsequently the rest of the component (A) is added in a lump or in lots to the polymerization reaction system and further the polymerization reaction is continued.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a rubber-modified styrenic resin as a raw material of a molded article having excellent impact resistance, especially DuPont impact strength, and a rubber-modified styrenic resin containing the rubber-modified styrenic resin. Composition.

[0002]

2. Description of the Related Art
Rubber-modified styrenic resins are used in various fields such as food containers, packaging materials, home appliances, and office automation equipment because of their excellent impact strength as well as strength and moldability. Due to the demand for reduction, further reduction in the thickness of the molded product and speeding up of the molding cycle are required, and improvement of impact resistance is important to meet the demand.

[0003] The rubber particles contained in the rubber-modified styrenic resin have a higher impact resistance as the particle size is larger, but the outer appearance such as surface gloss is reduced. , Preferably about 0.5 to 4 μm. In addition, in order to improve the impact resistance, the content of the inclusion occlusion (the styrene resin dispersed and contained in the rubber particles, that is, the occluded styrene resin) contained in the rubber particles of the rubber-modified styrene resin is also important. The impact resistance can be improved as the content of the inclusion occlusion is higher.

[0004] Heretofore, there has been known a method in which a peroxide is used as a polymerization initiator to promote a graft reaction at an early stage of the reaction to increase inclusion occlusion (for example, Ounther E., et al.
Molau and Henno. Keskkula (J. Polymer. Sci. A4, 1595
(1966); Polymer. Sci. A3, 4235 (1965), Applied
Polymer Symposia 1, 35 (1968)). However, when a peroxide is used, the amount of the styrene-based polymer grafted on the rubber particles increases, and this acts as a surfactant between the rubber particles and the continuous phase of the styrene-based resin. Is difficult to control.

[0005] JP-A-10-330438 discloses a rubber-modified styrene-based polymer having a controlled particle size, that is, a core-shell structure, by adding an aromatic vinyl monomer before phase inversion during a polymerization reaction. It is disclosed that a resin is obtained. According to this method, a rubber-modified styrene-based resin having excellent surface gloss can be obtained because the particle diameter is small, but the impact resistance is remarkably reduced because the particle diameter is 0.4 μm or less.

Japanese Patent Application Laid-Open No. 4-366116 discloses that the main raw material solution is divided into two types, a first raw material solution containing rubber and a second raw material solution containing no rubber, and the first raw material solution is divided into the first raw material solution.
It is continuously supplied to the reactor, where it is maintained in the state before phase inversion, and the initial polymerization solution and the second raw material solution are continuously supplied together to the second reactor, where it is brought to the state after phase inversion. A continuous production method of a rubber-modified styrenic resin in which initial polymerization is performed and the initial polymerization liquid is post-polymerized in a subsequent main polymerization reactor is disclosed. However, even in this method, the addition of the rubber-free raw material solution is before the phase inversion, and it is insufficient to increase the included occlusion amount at the optimum rubber particle diameter and further improve the impact resistance.

The present invention relates to a method for producing a rubber-modified styrene-based resin which can increase the amount of encapsulated occlusion and obtain a molded article of a rubber-modified styrene-based resin having improved impact resistance, especially DuPont impact strength. It is an object of the present invention to provide a rubber-modified styrenic resin composition containing

[0008]

The present invention relates to (A) a starting material which is a styrene monomer or a mixture of a styrene monomer and a vinyl monomer copolymerizable with the styrene monomer. 75 to 98% by weight of monomer and (B) rubbery polymer 25 to 2
In producing a rubber-modified styrenic resin by polymerizing a solution containing 1% by weight, a solution containing a part of the component (A) and a solution containing the component (B) are polymerized to a state of inversion of the rubber phase, and then the polymerization reaction system is started. Provided is a method for producing a rubber-modified styrenic resin, which comprises adding the remainder of the component (A) in a lump or in a divided manner, and subsequently performing a polymerization reaction.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The production method of the present invention is characterized in that the component (A) is dividedly added and the timing of the component (A) is dividedly added. The conditions are not particularly limited, and known polymerization means and polymerization conditions can be applied. For example, as a polymerization method, a bulk polymerization or a suspension polymerization is applied, and a polymerization reaction can be performed in a batch system or a continuous system.
To 180 ° C, preferably 90 to 150 ° C.

In the production method of the present invention, (A)
A part of a raw material monomer which is a styrene monomer as a component or a mixture of a styrene monomer and a vinyl monomer copolymerizable with the styrene monomer, and a rubber as a component (B) The polymerization reaction is carried out to the state of inversion of the rubber phase by using the polymer in the form and, if necessary, other components such as a polymerization initiator and a solvent.

The state of rubber phase inversion means the following state. At the initial stage when the raw material solution was charged and the reaction started,
The solution portion (resin phase) containing the styrene-based monomer and styrene-based polymer separates from the solution portion (rubber phase) containing the rubber-like polymer and the styrene-based monomer, and the rubber phase is a continuous phase. The phase becomes a dispersed phase. Thereafter, when the polymerization reaction is further advanced, the amount of the generated styrene-based polymer increases, and when the resin phase cannot remain as a dispersed phase, the resin phase becomes a continuous phase and the rubber phase becomes a dispersed phase (ie, The rubber-like polymer becomes particles), so-called phase inversion occurs, and a state in which such phase inversion occurs is called a rubber phase inversion state.

At the time of the rubber phase inversion, for example, monitoring the torque of the reactor, and observing a decrease in the torque due to the formation of the rubber particles by the styrene polymer phase becoming a continuous phase due to the phase inversion. The determination can be made by confirming the generation of rubber particles due to phase inversion by a method or a method of observing a particle size distribution curve by a laser diffraction / scattering type particle size distribution measuring device or the like using a polymerization solution sampled during the reaction. According to these methods, it was confirmed that the phase inversion occurred when the amount of the styrene-based polymer exceeded the amount of the rubbery polymer and became about 1.5 times.

Therefore, in the present invention, the timing of adding the remaining component (A) to the polymerization reaction system depends on the weight ratio (Aw) of the amount of styrene-based polymer produced (Aw) to the amount of rubbery polymer (Bw).
(w / Bw) is preferably in the range of 2 to 5.
When the weight ratio is 2 or more, the rubber particles in the polymerization reaction system are stably present, so that it is easy to control the particle diameter by adding the remaining component (A).
When the weight ratio is 5 or less, the viscosity of the polymerization reaction system can be appropriately maintained, so that the stirring operation during the subsequent polymerization reaction is smoothly performed. Incidentally, the amount of rubbery polymer,
It is the weight of the rubbery polymer at the time of charging.

Next, after the polymerization reaction is carried out until the rubber phase is inverted, the remainder of the component (A) is added to the polymerization
The above-mentioned portions are added in a divided manner, followed by a polymerization reaction to finally obtain a rubber-modified styrenic resin. At this stage, a polymerization initiator and a solvent can be added.

The balance of the component (A) added here is
It is preferably from 10 to 50% by weight, more preferably from 10 to 40% by weight, based on the total amount of the component (A). When the content is 10% by weight or more, the amount of inclusion occlusion can be increased,
When the content is 50% by weight or less, the dispersion state of the rubber particles in the polymerization reaction liquid can be easily controlled.

The styrene monomer of the component (A) used in the present invention includes styrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-t-butylstyrene, Alkyl-substituted styrenes such as 1,4-dimethylstyrene, α-methylstyrene, α
Α-alkyl-substituted styrenes such as -methyl-4-methylstyrene; halogenated styrenes such as 2-chlorostyrene and 4-chlorostyrene; and among these, styrene, 4-methylstyrene, α-methyl Styrene is preferred. These styrene monomers can be used alone or in combination of two or more.

Other monomers copolymerizable with the styrene monomer include acrylic acid or methacrylic acid, methyl acrylate or methyl methacrylate, ethyl acrylate or ethyl methacrylate, butyl acrylate or butyl methacrylate. , Acrylic acid (C1-C8) such as 2-ethylhexyl acrylate or 2-ethylhexyl methacrylate
Maleic acid such as ester or methacrylic acid (C1 to C8) ester, acrylonitrile, maleic anhydride, maleimide, N-methylmaleimide, N-substituted maleimide such as N-ethylmaleimide, and derivatives thereof; Among them, acrylates or methacrylates are preferred, and methyl methacrylate is particularly preferred. These monomers can be used alone or in combination of two or more.

When another monomer copolymerizable with the styrene-based monomer is used in combination, the content of the styrene-based monomer is 50 to 50%.
99% by weight is preferred.

Examples of the rubbery polymer as the component (B) used in the present invention include non-polymers such as butadiene rubber, butadiene-isoprene rubber, butadiene-acrylonitrile rubber, ethylene-propylene rubber, isoprene rubber, acrylic rubber and ethylene-vinyl acetate rubber. Styrene rubber, styrene
Styrene-based rubbers such as butadiene rubber and styrene-isoprene rubber can be mentioned. Among them, rubbers containing a butadiene unit in a molecule such as butadiene rubber and styrene-butadiene rubber are preferable. These rubbers can be used alone or in combination of two or more. The butadiene rubber may be a high cis type having a high content of cis-1,4 structure or a low cis type having a low content of cis-1,4 structure. Further, the polymerization form in the case of the copolymer is not particularly limited, and may be a block copolymer, a random copolymer, or a copolymer having a tapered block structure.

The amounts of the components (A) and (B) used are as follows:
75-98% by weight of component (A), preferably 85-98%
% By weight, more preferably 90 to 97% by weight, and the component (B) content is 25 to 2% by weight, preferably 15 to 2% by weight, and more preferably 10 to 3% by weight. 2% by weight of component (B)
When it is more than the above, the impact resistance can be increased, and 25% by weight
When it is less than the above, a decrease in rigidity can be prevented. The amount of the component (A) used means the total amount used.

In the present invention, (A) and (B)
A polymerization initiator can be added together with the components. As the polymerization initiator, cyclohexanone peroxide,
Ketone peroxides such as 3,3,5-trimethylcyclohexanone peroxide, methylcyclohexanone peroxide, di-t-butylperoxy-3,
3,5-trimethylcyclohexane, 1,1-bis (t
-Butylperoxy) cyclohexane, n-butyl-
Peroxy ketals such as 4,4-bis (t-butylperoxy) valerate, cumene hydroperoxide, diisopropylbenzene peroxide, 2,5-
Hydroperoxides such as dimethylhexane-2,5-dihydroperoxide, di-t-butylperoxydiisopropylbenzene, t-butylcumyl peroxide, α, α'-bis (t-butylperoxy-m-
Isopropyl) benzene, 2,5-dimethyl-2,5-
Dialkyl peroxides such as di (t-butylperoxy) hexine-3, decanoyl peroxide, lauroyl peroxide, benzoyl peroxide,
Diacyl peroxides such as 2,4-dichlorobenzoyl peroxide; peroxycarbonates such as bis (t-butylcyclohexyl) peroxydicarbonate; t-butylperoxybenzoate;
Organic peroxides such as peroxyesters such as dimethyl-2,5-di (benzoylperoxy) hexane can be mentioned. In addition, 2,2-azobis (2-
Examples thereof include azo compounds such as methylbutyronitrile) and 1,1-azobis (cyclohexane-1-carbonitrile) These polymerization initiators can be used alone or in combination of two or more.

The amount of the polymerization initiator to be used is 100 parts of the component (A).
The amount is preferably from 0.005 to 1.0 part by weight, particularly preferably from 0.01 to 0.2 part by weight, based on part by weight.

In the present invention, (A) and (B)
A solvent can be added together with the components. As the solvent, those inert to the reaction, for example, hexane, heptane, aliphatic hydrocarbons such as octane, cyclohexane,
Alicyclic hydrocarbons such as cycloheptane and cyclooctane; aromatic hydrocarbons such as toluene, xylene and ethylbenzene; ketones such as dimethyl ketone, methyl ethyl ketone and methyl isobutyl ketone; and esters such as ethyl acetate. be able to. These solvents are:
Species or a combination of two or more can be used.

The amount of the solvent used is preferably 0 to 100 parts by weight of the total amount of the styrene monomer 1 and the rubber as raw materials in order to maintain an appropriate polymerization reaction rate and reduce the burden of recovering the solvent. 0.1 to 50% by weight, particularly preferably 0.1 to 20% by weight.

In the present invention, in addition to the above components, chain transfer agents such as α-methylstyrene dimer, mercaptans, terpenes, and halogen compounds can be added as molecular weight regulators.

The rubber particles contained in the rubber-modified styrenic resin thus obtained are contained in the resin.
It may be dispersedly contained in various forms such as a single occlusion structure such as a core / shell structure or a capsule structure, a salami structure, and a maze structure.

The average particle diameter (volume average particle diameter) of the rubber particles contained in the rubber-modified styrene resin is determined in consideration of the impact resistance and surface gloss of the molded article, and the content of the included occlusion. It is desirable to set. The volume average particle diameter of the rubber particles is preferably 0.01 to 5.0 μm.
And more preferably 0.5 to 3.0 μm.

The particle size distribution of the rubber particles is not particularly limited, and a particle size distribution having a single peak,
A particle diameter distribution having a plurality of peaks having two or more peaks may be used, but a particle having a single particle diameter distribution is preferable.

The average particle diameter of rubber particles in such a rubber-modified styrene resin is determined by the type and molecular weight of rubber, the amount of rubber used, the type and amount of chain transfer agent, the polymerization temperature,
It can be adjusted by factors such as the stirring speed during polymerization.

The rubber-modified styrenic resin obtained by the production method of the present invention may be blended with other components to form a rubber-modified styrenic resin composition. Other components in this case include zinc stearate, higher fatty acid salts such as calcium stearate, higher fatty acid amides, lubricants such as bisamides such as ethylene bisstearyl amide, plasticizers such as mineral oil, phenolic compounds, and phosphorus compounds. Antioxidants, UV absorbers, flame retardants, antistatic agents, fillers,
Examples include a colorant and a release agent such as silicone oil.

The composition of the present invention is preferably such that a molded article obtained from the composition has one or both of the following properties.

The flexural modulus is 1400 MPa or more, preferably 1500 MPa or more.

The DuPont impact strength is 1.0 J or more, preferably 2.0 J or more.

[0034]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. Each measurement method described below is as follows. (1) Conversion rate of styrene-based monomer to styrene-based polymer The monomer remaining in the polymerization reaction solution sampled at appropriate times was subjected to gas chromatography (GC-14B, manufactured by Shimadzu Corporation).
Column PEG-20M) was used for the determination, and the reduction rate of the monomer was calculated as the conversion rate to the polymer. The production amount of the styrene-based polymer was calculated from the conversion rate and the monomer amount of the raw material charge. (2) Volume-average rubber particle diameter About 50 ml of a methyl ethyl ketone / acetone = 1/1 (volume ratio) solution was dissolved in about 50 mg of a rubber-modified styrene resin, and the resulting mixture was measured with a laser diffraction / scattering type particle size distribution analyzer (LA910, Horiba, Ltd.). It was determined from the obtained particle size distribution curve. (3) Content of inclusion occlusion 1.0 g of rubber-modified styrene resin pellets were precisely weighed, and 35 ml of a mixed solution of methyl ethyl ketone / acetone (volume ratio 1/1) was added thereto and shaken for 2 hours to dissolve. The solution was centrifuged in a refrigerated centrifuge for 20 minutes (-4 ° C,
15000 rpm). Discard the supernatant and remove the precipitate,
After vacuum drying at 60 ° C. for 3 hours, the gel content is determined from the following formula: gel content (%) = (weight of dried gel / weight of resin pellet) × 100, and further, the inclusion occlusion content is determined from the following formula. Was. The titration rubber content was determined by an iodine titration method. Inclusion occlusion content (%) = [gel content (%)
-Titration rubber content (%)] / Titration rubber content (%) (4) Flexural modulus, DuPont impact strength The flexural modulus is measured according to JIS K7203,
The DuPont impact strength was obtained by measuring a 50% breaking energy of a test piece having a thickness of 2 mm according to JIS K7211.

Example 1 1.1 kg of polybutadiene (Diene 55AE, manufactured by Asahi Kasei Kogyo Co., Ltd.) was added to 10.0 kg of 15.1 kg.
A raw material solution dissolved in kg of styrene monomer and 1.8 kg of ethylbenzene was charged into a reactor, and the temperature was raised to 135 ° C. to start a polymerization reaction. One hour and 40 minutes after the start of the polymerization, when the conversion of the styrene monomer became 30%,
Add 5.1 kg of the remaining styrene monomer into the reactor,
Further, the polymerization reaction was continued. When the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin.
Table 1 shows the measurement results.

Example 2 1.1 kg of polybutadiene (Diene 55AE, manufactured by Asahi Kasei Corporation) was used in 11.3 kg of 15.1 kg.
A raw material solution dissolved in kg of styrene monomer and 1.8 kg of ethylbenzene was charged into a reactor, and the temperature was raised to 135 ° C. to start a polymerization reaction. One hour and 40 minutes after the start of the polymerization, when the conversion of the styrene monomer reached 32.5%, 3.8 kg of the remaining styrene monomer was added into the reactor, and the polymerization reaction was further continued. . When the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

EXAMPLE 3 0.8 kg of polybutadiene (Diene 55AE, manufactured by Asahi Kasei Corporation) was converted into 10.3 kg of styrene monomer and 1.8 kg of ethylbenzene in a total amount of 15.4 kg of styrene monomer. Charge the dissolved raw material solution into the reactor,
The temperature was raised to 135 ° C. to start the polymerization reaction. One hour and 20 minutes after the start of the polymerization, the conversion of the styrene monomer was 25.1%.
At that time, 5.1 kg of the remaining styrene monomer was added to the reactor, and the polymerization reaction was continued. 70 conversion
%, The extruder with the degassing function was used,
Unreacted monomers and solvents were removed at ℃. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

Example 4 1.1 kg of polybutadiene (Diene 55AE, manufactured by Asahi Kasei Kogyo Co., Ltd.) was converted into 10.0 kg of styrene monomer and 1.8 kg of ethylbenzene in a total amount of 15.1 kg of styrene monomer. Charge the dissolved raw material solution into the reactor,
The temperature was raised to 135 ° C. to start the polymerization reaction. One hour and 40 minutes after the start of the polymerization, the conversion of the styrene monomer was 29.3%.
2.6 k of the remaining styrene monomer
g was added to the reactor, and after 15 minutes, the remaining 2.5 kg of the styrene monomer was added, and the polymerization reaction was continued. When the conversion exceeds 70%, use an extruder with a degassing function
At 30 ° C., unreacted monomers and solvent were removed. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

Example 5 1.1 kg of polybutadiene (Diene 55AE, manufactured by Asahi Kasei Kogyo Co., Ltd.) was converted to 10.0 kg of styrene monomer and 1.8 kg of ethylbenzene in a total amount of 15.1 kg of styrene monomer. Charge the dissolved raw material solution into the reactor,
Further, 200 ppm of t-butyl peroxybenzoate (Perbutyl Z, manufactured by NOF Corporation) was added to the styrene-based monomer, and the temperature was raised to 130 ° C. to initiate a polymerization reaction. One hour and 15 minutes after the start of the polymerization, when the conversion of the styrene monomer reached 37.8%, 5.1 kg of the remaining styrene monomer was added to the reactor, and the polymerization reaction was further continued. . When the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

Example 6 1.1 kg of polybutadiene (available from Asahi Kasei Kogyo KK, diene 55AE) was used for 14.3 kg of 15.1 kg.
A raw material solution dissolved in kg of styrene monomer and 1.8 kg of ethylbenzene was charged into a reactor, and the temperature was raised to 135 ° C. to start a polymerization reaction. One and a half hours after the start of the polymerization, when the conversion of the styrene monomer reached 20.9%, 0.8 kg of the remaining styrene monomer was added into the reactor, and the polymerization reaction was further continued. . When the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

Comparative Example 1 A raw material solution obtained by dissolving 1.1 kg of polybutadiene (manufactured by Asahi Kasei Kogyo Co., Ltd., Diene 55AE) in 15.1 kg of a styrene monomer and 1.8 kg of ethylbenzene was charged into a reactor. The polymerization reaction was carried out by elevating the temperature to 70 ° C., and when the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function.
The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

Comparative Example 2 A raw material solution obtained by dissolving 0.8 kg of polybutadiene (manufactured by Asahi Kasei Kogyo Co., Ltd., Diene 55AE) in 15.4 kg of a styrene monomer and 1.8 kg of ethylbenzene was charged into a reactor. The polymerization reaction was carried out by elevating the temperature to 70 ° C., and when the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function.
The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

Comparative Example 3 1.1 kg of polybutadiene (available from Asahi Kasei Kogyo Co., Ltd., Diene 55AE) was added to 10.0 kg of 15.1 kg.
A raw material solution dissolved in kg of styrene monomer and 1.8 kg of ethylbenzene was charged into a reactor, and the temperature was raised to 135 ° C. to start a polymerization reaction. Thirty minutes after the start of the polymerization, when the conversion of the styrene monomer reached 11.2%, 5.1 kg of the remaining styrene monomer was added into the reactor, and the polymerization reaction was further continued. When the conversion exceeded 70%, unreacted monomers and solvents were removed at 230 ° C. using an extruder with a degassing function. The molten strand was cooled and cut to obtain a pellet-shaped rubber-modified styrene resin. Table 1 shows the measurement results.

[0044]

[Table 1]

In Examples 1 to 5, since the component (A) was dividedly added and the subsequent addition was performed after the rubber phase had been inverted, the content of the occlusion included in the rubber particles could be increased. As a result, Dupont impact strength could be increased without lowering the flexural modulus. Example 6
Since the amount of the component (A) added at the time of the subsequent addition was small, the content of the included occlusion and the DuPont impact strength were lower than those of the other examples.

[0046]

According to the production method of the present invention, it is possible to obtain a rubber-modified styrenic resin as a raw material of a molded article having high rigidity and impact resistance by utilizing existing production equipment as it is.

Continued on the front page (72) Inventor Hirotaka Yamaguchi 157 Fukuzawa-cho, Himeji-shi, Hyogo F-term (reference) 4F071 AA10X AA22X AA33X AA67 AA71 AA77 AC09 AC12 AE04 AE05 AE07 AE09 AE11 AE16 AE17 AE22 AF17Y AF23Y AH04 AH04 AH04 AH07 AE052 BN061 BN071 BN141 BN151 BN161 BN211 CP032 EG036 EG046 EP016 EP026 FD016 FD022 FD056 FD076 FD096 FD106 FD136 FD136 FD162 FD176 GG01 GG02 BA01AC02 DB15 DB23 DB40 FA07 GA02

Claims (5)

[Claims] (A) 75 to 98% by weight of a raw material monomer which is a mixture of a styrene monomer or a styrene monomer and a vinyl monomer copolymerizable with the styrene monomer. When a rubber-modified styrene resin is produced by polymerizing a solution containing 25 to 2% by weight of the rubbery polymer (B), the solution containing a part of the component (A) and the component (B) is A method for producing a rubber-modified styrenic resin, which comprises polymerizing to a state, then adding the remainder of the component (A) to the polymerization reaction system in a lump or in a divided manner, and continuing the polymerization reaction. 2. When the weight ratio (Aw / Bw) of the amount (Aw) of the styrene-based polymer produced by the polymerization reaction and the amount (Bw) of the rubbery polymer is in the range of 2 to 5, (A) The method for producing a rubber-modified styrenic resin according to claim 1, wherein the remainder of the components is added to the polymerization reaction system. 3. The amount of the remaining component (A) added later is:
The method for producing a rubber-modified styrenic resin according to claim 1 or 2, wherein the amount is in the range of 10 to 50% by weight based on the total amount of the component (A). 4. A rubber-modified styrenic resin composition containing a rubber-modified styrenic resin obtained by the production method according to claim 1, 2 or 3. 5. The rubber-modified styrenic resin composition according to claim 4, wherein the molded article obtained from the composition has a flexural modulus of 1400 MPa or more and / or a DuPont impact strength of 1.0 J or more.