JP2712600B2 - High gloss impact resistant aromatic vinyl resin composition - Google Patents

Description

The present invention relates to a high-gloss impact-resistant aromatic vinyl resin, and more particularly, to an aromatic vinyl resin in the presence of a specific styrene-butadiene-based block copolymer. -Resistant aromatic vinyl resin having excellent impact resistance and appearance characteristics obtained by graft polymerization of an aromatic vinyl compound and adjusting the dispersed rubber particles in the obtained resin to a specific particle size and a specific particle form About.

b. Conventional technology Generally, aromatic vinyl resins such as styrene resins have many excellent properties such as easy flow during molding, transparency of shaped articles, and good surface gloss. There is a major drawback of poor impact resistance.

As a method for improving this defect, for example, a method of mechanically blending a rubber-like polymer in a resin, a method of graft-polymerizing an aromatic vinyl compound (for example, styrene) to the rubber-like polymer, and the like are known.

In particular, the method of graft-polymerizing an aromatic vinyl compound onto the rubbery polymer is generally carried out by a bulk polymerization method or a bulk-suspension polymerization method.For example, polybutadiene rubber is used as a rubbery polymer, and styrene is used as an aromatic vinyl compound. Is known as high impact polystyrene resin, which is used in televisions, radios,
It is widely used as a material for housings of household electric appliances such as cleaners and inner boxes of electric refrigerators. In that case, of course, it is practically excellent in impact resistance,
At the same time, excellent surface gloss is desired.

In general, the impact resistance of the resin produced by the above method can be improved by increasing the amount of the rubbery polymer or by increasing the particle size of the dispersed particles, but in this case, the surface gloss is deteriorated. .

On the other hand, the surface gloss can be improved by reducing the amount of the rubber-like polymer or reducing the particle size of the dispersed rubber particles, but in this case, the impact resistance is significantly reduced.

As described above, since impact resistance and surface gloss are contradictory characteristics, it has been difficult to obtain an impact-resistant aromatic vinyl resin having high impact resistance and excellent surface gloss.

Conventionally, methods for improving the properties of these impact-resistant aromatic vinyl resins have been disclosed in JP-B-61-50488 and JP-A-59-203.
No. 34, JP-A-60-203618 and the like have proposed a method for specifying specific properties such as solution viscosity, microstructure and branched structure of polybutadiene. However, when these methods are examined in detail, the gloss is certainly improved as compared with the case where conventional polybutadiene is used, but no practically satisfactory impact resistance has been obtained.

On the other hand, JP-B-42-17492, JP-B-48-18594, JP-A-61-143415, JP-A-63-48317, JP-A-63-16541
No. 3 proposes a method using a styrene-butadiene block copolymer having a strong affinity for an aromatic vinyl resin. According to these methods, the gloss of the obtained resin is improved, but the impact resistance is often significantly reduced, and the balance between the impact resistance and the gloss is insufficient. Was an issue.

c. Problems to be Solved by the Invention In view of such circumstances, the present inventors have intensively studied for the purpose of obtaining an impact-resistant aromatic vinyl resin in which impact resistance and gloss are highly balanced. As a result, in the presence of a styrene-butadiene-based block copolymer having a specific structure, radically polymerize an aromatic vinyl compound, and
The inventors have found that the above technical problem can be solved by adjusting the dispersed rubber particles in the obtained resin to a specific particle size range and particle morphology, and have reached the present invention.

d. Means for Solving the Problems The present invention relates to an aromatic vinyl containing as a dispersed particle a copolymer rubber phase obtained by polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene block copolymer rubber. (A) the styrene-butadiene block copolymer rubber content is 3 to 25% by weight; and (b) the rubber comprises a polystyrene block portion and a polybutadiene or butadiene / styrene copolymer block portion. The weight average molecular weight in terms of polystyrene (▲
▼) is 250,000 or more, molecular weight distribution (▲ ▼ / ▲ ▼) is 1.2 or more, ratio of peak molecular weight (PM) by GPC to ▲ ▼ (PM / ▲ ▼) is 1.02 or more, 25 ° C The viscosity of the 5% by weight styrene solution measured in the above is 50-100 centipoise, and the average vinyl bond content in the butadiene portion is 35%
Below, the total styrene content is 20-45% by weight, and the block styrene content is 85% of the total styrene content.
%, And (c) the dispersed particles dispersed in the aromatic vinyl resin composition have an average particle diameter of 0.25 to 1.0 micron, and have a shell-core structure or a shell-core structure.
An object of the present invention is to provide a high gloss impact-resistant aromatic vinyl resin composition characterized by being in a mixed state of a core structure and a spherical structure.

 Hereinafter, the present invention will be described.

The styrene-butadiene-based block copolymer rubber of the present invention comprises a polystyrene block portion and a polybutadiene or butadiene / styrene copolymer block portion. Although it can be obtained by a method as shown, other than this method, as long as a styrene-butadiene-based block copolymer rubber having the above specific structure can be obtained, two or more different block copolymers may be obtained by polymerization. What mixed the union rubber and what was obtained by any method can be used.

One of the preferred methods for producing the styrene-butadiene-based block copolymer rubber is to sequentially block copolymerize butadiene and styrene in a hydrocarbon solvent using an organolithium compound as an initiator. One or more anionic surfactants having a ₃ K group or an —OSO ₃ K group (K represents a potassium metal atom); and (ii) a general formula: CH ₂ ＣC ＝ CHR (where R is Represents a hydrogen atom or an alkyl group containing 1 to 3 carbon atoms.)
In this method, one or more 1,2-diene compounds coexist.

According to this production method, the 1,2-diene compound and -SO ₃ K
By adjusting the amount of the anionic surfactant having a group or —OSO ₃ K group, the preferred ▲ ▼ / ▲ ▼
And a styrene-butadiene-based block copolymer having the following formula:

The hydrocarbon solvent is not particularly limited, and aliphatic, alicyclic and aromatic hydrocarbon compounds which are liquid under the polymerization conditions can be used. Preferred hydrocarbon solvents include pentane, n-hexane, n-heptane, isooctane, n-decane, cyclohexane, methylcyclopentane, benzene, diethylbenzene and the like, and these are not only one kind but also a mixture of two or more kinds. There may be.

The organic lithium initiator has at least one lithium atom bonded to a hydrocarbon, and includes, for example, methyllithium, ethyllithium, n-propyllithium, n-butyllithium, sec-butyllithium, t-butyllithium.
Butyl lithium, n-hexyl lithium, cyclohexyl lithium, lithium benzene, lithium naphthalene,
1,4-dilithiobutane, 1,5-dilithiopentane, 1,10-
Dilithiodecane, 1,3,5-trilithiocyclohexane and the like, and preferred examples are n-butyllithium, se
Monolithium hydrocarbon compounds such as c-butyl lithium and t-butyl lithium.

In the above production method, the average vinyl bond content of the butadiene portion in the produced block copolymer rubber is 35%.
If it does not exceed the range, an ether or a tertiary amine compound can be added. Specific examples of ethers and tertiary amines include ethyl ether, tetrahydrofuran, dioxane, ethylene glycol methyl ether, diethylene glycol dimethyl ether, triethylamine, pyridine, NNN'N'-tetramethylethylenediamine, and the like. -SO ₃ K group or-
Examples of the anionic surfactant having an OSO ₃ K group include the following compounds.

(A) potassium alkylarylsulfonate; dodecylbenzenesulfonate, tetradecylbenzenesulfonate, hexadecylbenzenesulfonate,
Octadecyl benzene sulfonate, dibutyl naphthalene sulfonate, n-hexyl naphthalene sulfonate, dibutyl phenyl sulfonate, formalin condensate of naphthalene sulfonate, and the like.

Of these, potassium dodecylbenzenesulfonate, potassium tetradecylbenzenesulfonate, potassium hexadecylbenzenesulfonate and potassium octadecylbenzenesulfonate are preferred.

(B) potassium sulfonate having an amide bond; N-methyl-N-oleyltaurate, N-methyl-
N-lauryl taurate, N-phenyl-N-stearyl taurate, N-methyl-N-methanesulfonate laurylamide and the like.

Of these, potassium N-methyl-N-methanesulfonate laurylamide is preferred.

(C) potassium sulfonate having an ester bond; salts of condensates of oxy ethanesulfonic acid and oleic acid _{(C 17 H 38 COO CH 2} CH 2 SO 3 K), sulfosuccinate salts dioctyl salt, sulfo dioctyl maleate salt Such.

Preferred among these are the potassium salts of dioctyl sulfosuccinate.

(D) potassium salt of higher alcohol sulfate; sulfate of lauryl alcohol, sulfate of olein alcohol, sulfate of stearyl alcohol, and the like.

Of these, potassium salts of sulfates of lauryl alcohol are preferred.

(E) potassium salt of a sulfate having an ester bond; lauroyl trimethylene glycol sulfate (C ₁₁ H ₂₃ COO CH ₂ CH ₂ CH ₂ OSO ₃ K), caproyl ethylene glycol sulfate (C ₅ H
₁₁ COO CH ₂ CH ₂ OSO ₃ K) etc.

In addition, various sulfates and sulfonates such as polyoxyethylene alkyl ether sulfate and polyoxyethylene alkylphenyl ether sulfate can be used.

Of these, potassium salt of lauroyl trimethylene glycol sulfate is preferred.

Further, the formula used at the same time as the anionic surface active agent having such -SO ₃ K group or -OSO ₃ K group: CH ₂ = C = CHR (wherein, R represents a hydrogen atom or 1 to 3 carbon atoms Examples of the 1,2-diene compound represented by the following include propadiene and 1,2-butadiene.

Next, the styrene-butadiene block copolymer rubber having a specific structure of the present invention will be described.

As the styrene-butadiene-based block copolymer rubber, an AB type block copolymer is preferably used.

The styrene-butadiene block copolymer rubber has a weight average molecular weight in terms of polystyrene (ポ リ ス チ レ ン) of 250,00.
It is 0 or more, preferably 300,000. If it is less than 250,000, the particle size of the rubber particles may not be increased or rod-like particles may be formed, which is not preferable.

Of the styrene-butadiene block copolymer rubber
The 5% by weight styrene solution viscosity at 25 ° C. is 50-100 centipoise, preferably 60-90 centipoise, more preferably 60-80 centipoise. If it is less than 50 centipoise, the impact resistance is poor. If it exceeds 100 centipoise, the particle size of the dispersed rubber particles will be irregular, and the resulting resin will have poor gloss.

The average vinyl bond content in the butadiene portion of the styrene-butadiene block copolymer rubber is 35% or less, preferably 25% or less. If it exceeds 35%, the impact resistance is poor. From a manufacturing standpoint, the lower limit is 10%.

The styrene-butadiene-based block copolymer rubber has a total styrene content of 20 to 45% by weight, preferably 25 to 35% by weight. If the amount is less than 20% by weight, a salami structure of the block copolymer itself may be formed, which is not preferable. If the amount exceeds 45% by weight, a shell-core structure may not be formed and only a spherical structure may be formed.

When the block styrene content of the styrene-butadiene-based block copolymer rubber is less than 85% of the total styrene content, random bonds between styrene and butadiene increase, and the resulting resin has poor impact resistance.

The ratio of the styrene-butadiene block copolymer rubber in terms of polystyrene equivalent weight average molecular weight (重量) and number average molecular weight (▲) is (▲ / ▲) of 1.2.
Above, more preferably 1.2 to 1.9, still more preferably 1.3
~ 1.7. When ▲ ▼ / ▲ ▼ is less than 1.2, the obtained resin has poor impact resistance. The peak molecular weight (PM) of the styrene-butadiene block copolymer rubber obtained by (GPC) gel permeation chromatography and the weight average molecular weight in terms of polystyrene (▲
▼) and the ratio (PM / ▲ ▼) is 1.02 or more, preferably 1.0
It is 4 to 1.30, more preferably 1.05 to 1.25. PM / ▲
When ▼ is less than 1.02, the resulting resin has poor impact resistance. In the ordinary polymerization method, the value of PM / ▲ is 0.9 to 1.0 in the batch polymerization, and 0.7 to 0.8 in the continuous polymerization.

In the present invention, the specific styrene-butadiene-based block copolymer rubber is used, and at the same time, the average particle diameter of the dispersed particles (block copolymer particles) dispersed in the obtained resin is 0.25 to 1.0 μm. And preferably adjusted to a range of 0.3 to 0.7 microns. If the average particle size is less than 0.25 micron, the Izod impact strength is poor, and if it exceeds 1.0 micron, the surface gloss is poor. Adjustment of the particle size of the block copolymer particles is affected by various factors such as the shape of the stirring device in the polymerization tank, the number of rotations of the stirrer, the stirring time, and the polymerization temperature, and cannot be uniquely determined, Generally, in the stirring at the time of the graft polymerization, the stirring can be carried out by reducing the particle diameter by applying a condition such that stress is applied to the rubber, for example, by increasing the number of revolutions.

Further, when the structure of the dispersed particles is a shell-core structure or a mixed state of a shell-core structure and a spherical structure, excellent gloss is obtained, which is most preferable. Particles having a shell-core structure referred to here are Die Angewandte Makromolekulare C
hemie 58-59 The morphology can be observed with reference to pages 175-198 (1977), in which the shell is a styrene-butadiene block copolymer rubber and the core is a structure of an aromatic vinyl polymer.

For the method of making core-shell particles, for example, Die Ange
wandte Makromolekulare Chemie 58-59 pp. 175-198 (1
977), the styrene-butadiene block copolymer rubber used has a styrene block content,
It can be carried out by adjusting the molecular weight of the styrene block and the degree of polymerization of the aromatic vinyl compound.

In the present invention, an aromatic vinyl compound is graft-polymerized to a styrene-butadiene-based block copolymer rubber having a solution viscosity of a styrene-butadiene-based block copolymer rubber, a total styrene content, a block styrene content, and the like within a specified range. Thereby, core-shell particles can be obtained.

The composition of the present invention is obtained by using the above specific styrene-butadiene-based block copolymer rubber and graft-polymerizing an aromatic vinyl compound thereto.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, P-methylstyrene, vinyltoluene,
Vinyl naphthalene, vinyl ethyl benzene, vinyl xylene and the like can be mentioned, preferably styrene, α-methyl styrene, P-methyl styrene,
More preferably, it is styrene.

The mixing ratio between the styrene-butadiene-based block copolymer and the aromatic vinyl compound is 3 to 25% by weight, preferably 5 to 15% by weight, more preferably 7 to 13% by weight, and the latter is 97 to 75% by weight. %, Preferably 95 to 85% by weight, more preferably 93 to 87% by weight. If the amount of the styrene-butadiene-based block copolymer rubber is less than 3% by weight, the impact resistance of the obtained resin is reduced, and it is difficult to achieve the object of the present invention. If it exceeds 25% by weight, the viscosity of the graft polymerization solution is increased. Becomes very high, so that it becomes difficult to actually perform graft polymerization.

The method of radically copolymerizing an aromatic vinyl compound with the specific styrene-butadiene-based block copolymer rubber is not particularly limited. For example, an aromatic compound obtained by dissolving the styrene-butadiene-based block copolymer rubber is used. It can be carried out by bulk polymerization of a vinyl compound solution or radical polymerization by a combination of bulk polymerization and suspension polymerization.

When a styrene-butadiene-based block copolymer and an aromatic vinyl compound are radically polymerized by bulk polymerization, the styrene-butadiene-based block copolymer is dissolved in the aromatic vinyl compound, and then, if necessary, a molecular weight regulator. Is added.

Examples of the molecular weight regulator include α-methylstyrene dimer, n-decyl mercaptan, tert-dodecyl mercaptan, 1-phenylbutene-2-fluorene, mercaptans such as dipentene and chloroform, terpenes, and halogen compounds.

Furthermore, a general lubricant is added in order to improve the moldability of the obtained resin. For example,
Ester lubricants such as butyl stearate and butyl phthalate, and lubricants used in conventional resin processing such as mineral toyl and paraffin wax can be used.

After dissolving these molecular weight regulators and lubricants in the above polymer solution, as an initiator, for example, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, dicumyl peroxide, diisopropyl peroxydicarbonate, tar- Shari-butyl peroxyacetate,
Di-tert-butyl diperoxyisophthalate,
2,5-Dimethyl-2,5-di (t-butylperoxy) hexane or azobisisobutyronitrile is added, and the mixture is stirred under an inert gas atmosphere at a reaction temperature of 60 to 200 ° C. While the reaction is complete. In the case of performing thermal polymerization without a catalyst, the polymerization is usually performed by heating at 100 to 200 ° C. to complete the reaction.

During the bulk polymerization reaction, it is usually preferable to stir effectively until the polymerization rate of the aromatic vinyl compound reaches about 30%. In the present invention, the particle diameter of the block copolymer rubber is specified. It is necessary to adjust the agitation so as to fall within the range. On the other hand, after the conversion of the aromatic vinyl compound exceeds about 30%, it is preferable to reduce the stirring.

At this time, a hydrocarbon solvent such as toluene, ethylbenzene, or xylene may be added to reduce the viscosity of the polymerization system.

After completion of the polymerization, the monomer and the solvent are recovered by removing the monomer and removing the solvent by a vent-type ruder or steam stripping.

When radical polymerization is performed by a combination of bulk polymerization and suspension polymerization, first, bulk polymerization is performed until about 10 to 45% by weight of a monomer (aromatic vinyl compound) is converted into a polymer, and then the reaction solution is treated with polyvinyl alcohol. The suspension is dispersed in an aqueous solution in which a suspension stabilizer such as polymethacrylate or tricalcium phosphate is dissolved, and while maintaining the suspension, the reaction temperature is adjusted to 60 to 160 ° C. to complete the polymerization. After completion of the polymerization, the suspension stabilizer is sufficiently washed with water to remove and dry, and then the aromatic vinyl resin is recovered.

In addition, when the radical polymerization is performed by the bulk polymerization or the bulk-suspension polymerization, it is preferable that 50% by weight or more of the monomer used is the aromatic vinyl compound, and less than 50% by weight of the monomer is acrylonitrile other than the compound. , Methacrylonitrile, acrylic acid, methyl acrylate, methyl methacrylate and the like.

In addition, resins obtained by the above polymerization methods include known antioxidants, for example, 2,6-tert-butyl-4-methylphenol, 2- (1-methylcyclohexyl) -4,6-dimethylphenol, 2,2'-methylene-bis (4-ethyl-6-tert-butylphenol), 4,4'-thiobis-
(6-tert-butyl-3-methylphenol), dilaurylthiodipropionate, tris (di-nonylphenyl) phosphite, wax; known UV absorbers such as p-tert-butylphenyl salicylate, 2,2 '-
Dihydroxy-4-methoxybenzophenone, 2-
(2'-hydroxy-4'-n-octoxyphenyl)
Benzothiazole; known lubricants, for example, paraffin wax, stearic acid, hydrogenated oil, stearamide, methylenebisstearamide, n-butylstearate, ketone wax, octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride; known flame retardants, For example, antimony oxide, aluminum hydroxide, zinc borate, tricresyl phosphate, chlorinated paraffin, tetrabromobutane, hexabromobenzene, tetrabromobisphenol A; a known antistatic agent, for example, stearoamidopropyldimethyl-β-hydroxyethyl Ammonium nitrate; known colorants, such as titanium oxide, carbon black, and other inorganic or organic pigments; known fillers, such as calcium carbonate, clay, silica, glass fiber, glass Spheres, carbon fibers, and the like can be added as needed.

e. Examples Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples.

In the examples, parts and% indicate parts by weight and% by weight, respectively, unless otherwise specified.

The data shown in the examples were measured according to the following methods.

The microstructure of the styrene-butadiene-based block copolymer rubber was measured by an infrared method (Morello method), and the styrene solution viscosity was measured by a Cannon-Fenske viscometer.

The amount of bound styrene in the styrene-butadiene-based block copolymer was determined by measuring the intensity of an infrared absorption peak due to a phenyl group at a wave number of 699 cm ^-1 and determining the amount from a previously determined calibration curve.

The molecular weight distribution of the styrene-butadiene block-based copolymer rubber was determined by using HLC-812A type GPC manufactured by Toyo Soda Kogyo Co., Ltd.
Was measured under the following conditions.

Column: Toyo Soda Kogyo Co., Ltd. column GMHXL × 2
This mobile phase; tetrahydrofuran Sample concentration; 0.1% by weight Measurement temperature; 40 ° C Detector; differential diffractometer ▲ ▼ / ▲ ▼ and PM / ▲ ▼ are calculated by calculating ▲ ▼, ▲ ▼, PM converted to standard polystyrene respectively did. The amount of block styrene in the styrene-butadiene block copolymer was determined by H'-NMR according to Rubb. Chem, Tec.
h., 54 685 (1981).

The physical properties of the impact-resistant polystyrene resin were measured according to the following methods.

Izod Impact Strength (1/4 inch, notched); 8 _oz
Using an injection molding machine, a molded product obtained by molding at a cylinder temperature of 200 ° C. was measured according to ASTM D-256.

Tensile strength; using an 8 _oz injection molding machine, cylinder temperature 200
The molded product obtained by molding at ℃ was measured according to ASTM D-638.

Gloss; A molded article obtained by molding at a cylinder temperature of 200 ° C. using an 8 _oz injection molding machine was measured for the reflection glossiness at 60 ° according to ASTM D-523.

Measurement of median particle size of dispersed rubber particles; resin pellet 1
２2 grains were placed in about 50 ml of dimethylformamide and left for about 3 hours. Then, this dimethylformamide solution was added to the electrolyte solution (ISOTONII), and the resulting solution was measured with a Coulter counter to obtain a proper particle concentration. 50 from particle size distribution
% Median diameter.

When the particle diameter was 0.4 μm or less, the dimethylformamide solution was measured using a Coulter N4 type submicron particle analyzer.

Example 1 A reactor with a jacket and a stirrer having an inner volume of 50 was charged with 18 kg of cyclohexane, 2.1 kg of butadiene, and 0.9 of tetrahydrofuran.
g, 0.4 g of 1,2-butadiene and 0.5 g of potassium dodecylbenzenesulfonate were added, and after adjusting the temperature to 45 ° C., 1.47 g of n-butyllithium was added to carry out polymerization. 15 minutes after reaching the maximum temperature, 0.9 kg of styrene is added,
The polymerization was continued for another 30 minutes. To this polymer solution, 2,6-di-tert-butyl-4-methylphenol was added as a stabilizer at a ratio of 0.5% to the polymer, and the solvent was removed by steam stripping. To obtain a block polymer A. Table 1 shows the properties of the obtained polymer. A mixture of 10 parts of the block polymer A and 90 parts of styrene was stirred at room temperature for 8 hours and uniformly dissolved. This solution was transferred to a reactor equipped with a jacket and a stirrer having an internal volume of 10, 0.04 parts of tert-dodecyl mercaptan was added, and the mixture was polymerized at 95 ° C. until the conversion of styrene became about 30%. The stirring at this time is 400 rpm
At a rotation speed of Next, 0.05 parts of dicumyl peroxide was added per 100 parts of the polymerization solution, and 3 parts of tricalcium phosphate as a suspension stabilizer, and 150 parts of water containing 0.005 part of sodium dodecylbenzenesulfonate as a surfactant were added, The solution was suspended under stirring. This suspension mixture was heated with stirring at 120 ° C. for 4 hours and at 140 ° C. for 4 hours to carry out polymerization. The obtained beaded resin was separated by filtration, washed with water, dried with hot air, and then pelletized using an extruder. The impact-resistant styrene resin thus obtained was injection molded to prepare a test piece for measuring physical properties. Table 2 shows the measurement results of the properties.

Examples 2 to 5 According to the method of Example 1 described above, while changing the amounts and ratios of the chemicals used, the copolymers in Table 1 were obtained, and the physical properties were evaluated. Table 2 shows the results.

Comparative Example 1 A copolymer was prepared in the same manner as in Example 1 except that 1,2-butadiene and potassium dodecylbenzenesulfonate were not used and the amount of n-butyllithium was changed to 1.6 g. Obtained and measured physical properties. Table 2 shows the results.

Comparative Examples 2 to 5 According to the method of Example 1, the amounts and ratios of the chemicals used were changed to obtain the copolymers shown in Table 1, and the physical properties were evaluated. Table 2 shows the results.

As is clear from the results shown in Table 2, Examples 1 to 5
Are made of shell / core with large rubber particle diameter
It has a spherical structure, excellent gloss, and excellent impact resistance.

On the other hand, since the resin of Comparative Example 1 has a sharp molecular weight distribution, it has poor impact resistance and is somewhat poor in gloss.

The resin of Comparative Example 2 had a too low styrene content,
No core structure is obtained, resulting in poor gloss.

The resin of Comparative Example 3 has a too high styrene content, has a spherical structure, and has very poor impact resistance.

The resin of Comparative Example 4 is slightly inferior in gloss because the styrene block ratio is too low.

The resin of Comparative Example 5 has a shell
Core structure cannot be formed, and gloss is very poor.

f. Effects of the Invention According to the present invention, an aromatic vinyl resin having high gloss and excellent impact resistance can be obtained, and parts of household electric appliances such as a television, a refrigerator, an air conditioner, and a washing machine, a personal computer, and a word processor. It is useful for office equipment parts, building materials, sundries, packaging materials, etc.

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Claims (1)

(57) [Claims] 1. An aromatic vinyl resin composition containing, as dispersed particles, a copolymer rubber phase obtained by polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene block copolymer rubber, comprising: (B) the styrene-butadiene block copolymer rubber content is 3 to 25% by weight; (b) the rubber comprises a polystyrene block portion and a polybutadiene or butadiene / styrene copolymer block portion; Molecular weight (▲ ▼) is 25
The molecular weight distribution (▲ ▼ / ▲ ▼) is 1.2 or more, and the ratio of peak molecular weight (PM) by GPC to ▲ ▼ (PM /
▲) is 1.02 or more, and the viscosity of the 5% by weight styrene solution measured at 25 ° C. is 50 to 50%.
100 centipoise, the average vinyl bond content of the butadiene portion is 35% or less, the total styrene content is 20 to 45% by weight, the block styrene content exceeds 85% of the total styrene content, and (c) The dispersed particles dispersed in the aromatic vinyl resin composition have an average particle diameter of 0.25 to 1.0 μm, and the structural form is a shell-core structure or a mixed state of a shell-core structure and a spherical structure. High gloss impact resistant aromatic vinyl resin composition.