JP2658295B2 - Method for producing impact-resistant aromatic vinyl resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Field of the Invention The present invention relates to a method for producing an impact-resistant aromatic vinyl-based resin, and more specifically, in the presence of a specific styrene-butadiene-based block copolymer, A method for producing an impact-resistant aromatic vinyl-based resin having excellent impact resistance and appearance characteristics by graft-polymerizing an aromatic vinyl compound and adjusting dispersed rubber particles in the obtained resin to a specific particle size. About.

b. Conventional technology Generally, aromatic vinyl resins such as styrene resins have many excellent properties such as good flowability during molding, transparency of molded 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, good 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 properties, it has been difficult to obtain an impact-resistant aromatic vinyl resin having high impact resistance and good 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
It has been 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 the present invention has been achieved.

d. Means for Solving the Problems The present invention provides a method for polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene-based block copolymer, wherein the styrene-butadiene-based block copolymer has a polystyrene equivalent weight average The ratio (▲ ▼ / ▲ ▼) between the molecular weight (▲ ▼) and the number average molecular weight (▲ ▼)
1.20 or more, gel permeation chromatography (GPC)
(PM / ▲ ▼) of peak molecular weight (PM) obtained by the method and weight average molecular weight in terms of polystyrene (▲ ▼)
Is 1.02 or more, Mooney viscosity (ML _{1 + 4 at} 100 ° C) is 20-100, and the viscosity of a 5% by weight styrene solution measured at 25 ° C is 10-
A styrene-butadiene-based block copolymer having 100 centipoise, a total styrene content of 3 to 20% by weight, a block styrene content of 90% or more of the total styrene content, and a vinyl bond content of a butadiene portion of 13 to 30%; Another object of the present invention is to provide a method for producing an impact-resistant aromatic vinyl resin, characterized in that the average particle size of the block copolymer particles dispersed in the obtained resin is adjusted to a range of 0.4 to 1.4 μm.

 Hereinafter, the present invention will be described in detail.

Conventionally, when styrene and butadiene are block-polymerized in a hydrocarbon solvent using a generally used batch polymerization method or continuous polymerization method using an organolithium catalyst, the present invention is limited to ▲ / ▲.
A styrene-butadiene-based block copolymer having values of ▼ and PM / ▲ ▼ cannot be obtained. Usually, for batch polymerization, ▲ ▼ / ▲ ▼ is 1.1 ~ 1.3, PM / ▲
▼ is 0.9 to 1.0, and in continuous polymerization, ▲ ▼ / ▲
▼ is 1.8 to 2.6, PM / ▲ ▼ is 0.7 to 0.8.

The styrene-butadiene-based block copolymer of the present invention can be obtained in a hydrocarbon solvent using an organolithium catalyst by the following method. As long as a butadiene-based block copolymer can be obtained, a method by polymerization, a mixture of two or more different block copolymers, or a method obtained by any method can be used.

The styrene - One preferred method for producing butadiene block copolymer, as an initiator an organolithium compound in a hydrocarbon solvent, upon sequentially block copolymer of butadiene and styrene, (i) -SO ₃ K group or -OS
One or more anionic surfactants having an O ₃ K group (K represents a potassium metal atom), and (ii) a general formula: CH ₂
ＣC ＝ CHR (wherein R represents a hydrogen atom or an alkyl group containing 1 to 3 carbon atoms).
This is a method in which one or more 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 desired ▲ ▼ / ▲
A styrene-butadiene block copolymer having ▼ and PM / ▲ ▼ can be obtained.

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, an ether or a tertiary amine compound can be added as long as the vinyl bond content of the butadiene portion in the produced block copolymer does not exceed 30%. Specific examples of ethers and tertiary amines include ethyl ether, tetrahydrofuran, dioxane, ethylene glycol methyl ether, diethylene glycol dimethyl ether, triethylamine,
Examples include pyridine, NNN'N'-tetramethylethylenediamine, and the like. Examples of the anionic surfactant having the -SO ₃ K groups or -OSO ₃ K group there are the following such 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-based block copolymer having a specific structure of the present invention will be described.

As the styrene-butadiene-based block copolymer of the present invention, an AB type block copolymer is preferably used. The styrene-butadiene-based block copolymer of the present invention has a ▼ / ▲ ▼ of 1.2 or more, preferably 1.2 to 1.
9, more preferably 1.3 to 1.7. ▲ ▼ / ▲
When ▼ is less than 1.2, the resulting resin has poor impact resistance.
Further, the ratio (PM // ▼) of the peak molecular weight (PM) and the weight average molecular weight (▲) obtained by the GPU of the styrene-butadiene block copolymer of the present invention is 1.02 or more, preferably 1.04 to 1.30, More preferably 1.05-1.
25. When PM / ▲ ▼ is less than 1.02, the resulting resin has poor impact resistance.

The Mooney viscosity of the styrene-butadiene-based block copolymer of the present invention is 20 to 100, preferably 25 to 90. 20
If it is less than 10, the cold flow of the block copolymer itself becomes large, and it becomes difficult to handle as a rubber, and the resulting resin has poor impact resistance and gloss. Conversely, if it exceeds 100, the particle size of the dispersed rubber particles becomes irregular,
The gloss of the obtained resin is inferior.

The styrene-butadiene-based block copolymer of the present invention
The viscosity of the 5% by weight styrene solution at 25 ° C. is 10 to 100 centipoise, preferably 15 to 90 centipoise, more preferably 20 to 85 centipoise, and particularly preferably 25 to 80 centipoise. If it is less than 10 centipoise, not only the impact resistance is poor but also the gloss 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 total styrene content of the styrene-butadiene block copolymer of the present invention is 3 to 20% by weight, preferably 5 to 18% by weight. If the amount is less than 3% by weight, the cold flow of the block copolymer itself becomes remarkably large, and not only is it difficult to handle as a rubber, but also the resulting resin has poor impact resistance. If it exceeds 20% by weight, the resulting resin will have poor impact resistance.

The block styrene content of the styrene-butadiene block copolymer of the present invention is 90% of the total styrene content.
That is all. If it is less than 90%, the number of random bonds between styrene and butadiene increases, and the resulting resin has poor impact resistance.

The styrene-butadiene block copolymer of the present invention has a vinyl bond content of 13 to 30%, preferably 14 to 25%. If it is less than 13%, the resulting resin has poor impact resistance and gloss. If it exceeds 30%, the gloss is good but the impact resistance is poor.

In the present invention, it is necessary to use the specific styrene-butadiene-based block copolymer at the same time that the average particle diameter of the block copolymer particles dispersed in the obtained resin is in the range of 0.4 to 1.4 μm. And preferably 0.
Adjust to a range of 5 to 1.2 μm. If the average particle size is less than 0.4 μm, the Izod impact strength is poor, and if it exceeds 1.4 μm, only those having poor surface gloss can be obtained. Adjustment of the particle size of the block copolymer particles depends on 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 unambiguously determined. Generally, in the stirring at the time of the graft polymerization, the stirring can be carried out by reducing the particle size by applying a condition such that stress is applied to the rubber, for example, by increasing the number of revolutions.

In the method of the present invention, the specific styrene-butadiene-based block copolymer is used, and an aromatic vinyl compound is graft-polymerized on the block copolymer.

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 block copolymer is less than 3% by weight,
The impact resistance of the obtained resin is lowered, 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 becomes extremely 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 is not particularly limited. For example, an aromatic vinyl compound in which the styrene-butadiene-based block copolymer is dissolved The polymerization can be carried out by bulk polymerization of the solution or by radical polymerization using 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 degree of polymerization of the aromatic vinyl compound reaches about 30%, and particularly in the present invention, the particle size of the block copolymer is preferably not more than 30%. It is necessary to adjust the stirring so as to fall within the scope of the invention. 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, 50% by weight or more of the monomer used is preferably the aromatic vinyl compound, and less than 50% by weight of the monomer is an acrylic compound other than the compound. It may be replaced with an aliphatic vinyl compound such as nitrile, methacrylonitrile, acrylic acid, methyl acrylate and methyl methacrylate.

In addition, a resin obtained by each of the above polymerization methods may contain a known antioxidant, for example, 2,6-di-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 such as paraffin wax, stearic acid, hydrogenated oil, stearamide, methylenebisstearamide, n-butyl stearate,
Ketone wax, octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride; known flame retardants such as antimony oxide, aluminum hydroxide,
Zinc borate, tricresyl phosphate, chlorinated paraffin, tetrabromobutane, hexabromobenzene, tetrabromobisphenol A; known antistatic agents, for example, stearoamidopropyldimethyl-β-hydroxyethylammonium nitrate; known colorants For example, titanium oxide, carbon black, and other inorganic or organic pigments; known fillers such as calcium carbonate, clay, silica, glass fiber, glass sphere, and carbon fiber can be added as necessary.

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 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 copolymer was measured using HLC-802A type GPC manufactured by Toyo Soda Kogyo Co., Ltd. under the following conditions.

Column: 2 columns from Toyo Soda Kogyo Co., Ltd. GMHXL Mobile phase: Tetrahydrofuran Sample concentration; 0.1% by weight Measurement temperature; 40 ° C Detector: Differential segregation analyzer ▲ ▼ / ▲ ▼ and PM / ▲ ▼ are converted to standard polystyrene ▲ ▼, ▲ ▼, PM were calculated. The block styrene content of the styrene-butadiene-based block copolymer was determined by H ¹ -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, with notch); Measured according to ASTM D-256 for a molded product obtained by molding at a cylinder temperature of 200 ° C. using an 8 _oz injection molding machine.

Tensile strength; cylinder temperature 200 ° C using 8 _oz injection molding machine
The molded article obtained by molding was measured according to ASTM D-638.

Gloss; For a molded product obtained by molding at a cylinder temperature of 200 ° C. using an 8 _oz injection molding machine, 6 parts were obtained in accordance with ASTM D-523.
The reflection gloss of 0 ° was measured.

Measurement of median particle diameter of dispersed rubber particles; resin pellet 1
Two grains were put in about 50 ml of dimethylformamide and left for about 3 hours. Then, the dimethylformamide solution was added to the electrolyte solution (ISOTON II), and the resulting solution was measured for a proper particle concentration by a Coulter counter to obtain. 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 having an inner volume of 50 and equipped with a jacket and a stirrer was charged with 18 kg of cyclohexane, 2.7 kg of butadiene, and 1.3 kg of tetrahydrofuran.
kg, 0.4 g of 1,2-butadiene and 0.7 g of potassium dodecylbenzenesulfonate were charged, the temperature was adjusted to 45 ° C., and 2.4 g of n-butyllithium was added to carry out polymerization. Ten minutes after the maximum temperature reached 93 ° C, 0.3 kg of styrene was added, and 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 then the solvent was removed by steam stripping.
It dried with the hot roll of ° C, and obtained 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. The solution was transferred to a reactor equipped with a jacket / stirrer having an internal volume of 10 and 0.05 parts of tert-dodecyl mercaptan was added.
Polymerization was carried out until it reached 0%. The stirring at this time is 2
The rotation was performed at 50 rpm. Then, 0.05 parts of dicumyl peroxide was added per 100 parts of the polymerization solution, and 3 parts of tribasic calcium phosphate was further added as a suspension stabilizer, and sodium dodecylbenzenesulfonate 0.000 was added as a surfactant.
150 parts of water containing 5 parts were added and 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.

Example 2 The amount of butadiene was 2.85 kg and the amount of 1,2-butadiene was 0.3.
5 g, the amount of potassium dodecylbenzenesulfonate 0.60
g, the amount of n-butyllithium is 0.21 g, and the amount of styrene is
A block polymer B was obtained in the same manner as in Example 1 except that the weight was changed to 15 kg. Table-Properties of block polymer B
1 is shown. Next, an impact-resistant styrene resin was obtained in the same manner as in Example 1 using the block polymer B. Table 2 shows the physical properties of this resin.

Example 3 A block polymer C was obtained in the same manner as in Example 1, except that the amount of butadiene was changed to 2.55 kg, the amount of styrene was changed to 0.45 kg, and the amount of tetrahydrofuran was changed to 9.0 g. Table 1 shows the properties of the block polymer C. Next, an impact-resistant styrene resin was obtained in the same manner as in Example 1 using the block polymer C. Table 2 shows the physical properties of this resin.

Example 4 A block polymer D was obtained in the same manner as in Example 1, except that the amount of 1,2-butadiene was changed to 0.90 g and the amount of potassium dodecylbenzenesulfonate was changed to 1.05 g. Table 1 shows the properties of the block polymer D. Next, an impact-resistant styrene resin was obtained in the same manner as in Example 1 using the block polymer D. Table 2 shows the physical properties of this resin.

Comparative Examples 1-2 Except that the charged amounts of butadiene and styrene were changed,
Block polymers E and F having different total styrene contents were obtained in the same manner as in Example 1. Table 1 shows the properties of these block polymers. Using the block polymer E or the block polymer F, an impact-resistant styrene resin was produced in the same manner as in Example 1. Table 2 shows the physical properties of these resins.

Comparative Examples 3 and 4 Block polymers G and H having different vinyl bond contents were obtained in the same manner as in Example 1 except that the charged amount of tetrahydrofuran was changed. Table 1 shows the properties of these block polymers. Next, using the block polymer G or the block polymer H, an impact-resistant styrene resin was produced in the same manner as in Example 1. Table 2 shows the physical properties of these resins.

Comparative Examples 5-6 Example 1 except that the amount of n-butyllithium was changed.
In the same manner as in the above, block polymers I and J having different Mooney viscosities and solution viscosities were obtained. Table 1 shows the properties of these block polymers. Next, using the block polymer I or the block polymer J, an impact-resistant styrene resin was produced in the same manner as in Example 1.
Table 2 shows the physical properties of these resins.

Comparative Example 7 A block polymer K obtained by ordinary batch polymerization was obtained in the same manner as in Example 1 except that 1,2-butadiene and potassium dodecylbenzenesulfonate were not used. Table 1 shows the properties of the block polymer K. Next, an impact-resistant styrene resin was produced in the same manner as in Example 1 using the block polymer K. Table 2 shows the physical properties of this resin.

Comparative Example 8 Two reactors with a jacket stirrer having an internal volume of 15 were connected in series, and the bottom of the first reactor was cyclohexane 12 kg / hr, butadiene 1.8 kg / hr, n-butyllithium 1.7 g / hr and tetrahydrofuran 0.9 g. / hr was supplied by a metering pump and polymerized at 102 ° C. To the polymerization solution overflowing from the top of the reactor, 0.2 kg / hr of styrene and 1.0 kg / hr of cyclohexane were added and fed to the bottom of the second reactor. The polymerization temperature was adjusted to 108 ° C, and 0.5% by weight based on the produced polymer
2,6-di-tert-butyl-4-methylphenol was added to obtain a block polymer L. Block polymer L
Table 1 shows the properties. Then, in the same manner as in Example 1, an impact-resistant styrene resin was obtained using the block polymer L. Table 2 shows the physical properties of this resin.

Comparative Example 9 A partial block type block polymer M was obtained in the same manner as in Example 1 except that butadiene and styrene were simultaneously charged and polymerized. Next, in the same manner as in Example 1, an impact-resistant styrene resin was obtained using the block polymer M. Table 2 shows the physical properties of the resin.

Comparative Examples 10 to 11 When performing a graft reaction of a mixed solution of block polymer A and styrene at 105 ° C., the stirring rotation speed was 500 rpm (Comparative Example
Example 1 except for changing to 10) and 150 rpm (Comparative Example 11)
In the same manner as in the above, an impact-resistant styrene resin was produced. Table 2 shows the physical properties of these resins.

As is clear from the results shown in Tables 1 and 2,
The resins obtained in Examples 1 to 4 are excellent in all of Izod impact strength, gloss and tensile strength in a well-balanced manner.

On the other hand, the resins of Comparative Examples 1 and 2 used those having a total styrene content outside the range of the present invention as the block copolymer, and were inferior in Izod impact strength.

In the resins of Comparative Examples 3 and 4, the vinyl bond content of the block copolymer was out of the range of the present invention, and Comparative Example 3 was inferior in Izod impact strength and gloss, and Comparative Example 4 was inferior in Izod impact strength.

The resins of Comparative Examples 5 and 6 used block copolymers having Mooney viscosities and solution viscosities outside the scope of the present invention. Comparative Example 5 was inferior in Izod impact strength and gloss. Is inferior in gloss.

Comparative Example 7 has ▲ ▼ / ▲ ▼ and PM / ▲ ▼
Are those using a resin outside the scope of the present invention, and have poor Izod impact strength.

Comparative Example 8 uses a resin whose PM // is out of the range of the present invention, and is also inferior in Izod impact strength.

Comparative Example 9 uses a resin having a block styrene content outside the range of the present invention, and is inferior in Izod impact strength.

Comparative Examples 10 and 11, using a resin having a particle diameter of the block copolymer particles outside the range of the present invention, the Izod impact strength in Comparative Example 10 is poor in gloss and tensile strength in Comparative Example 11, and I have.

f. Effects of the Invention According to the present invention, a specific styrene-butadiene-based block copolymer is used, and by adjusting the particle size of rubber particles dispersed in a resin to a specific range, impact resistance and appearance gloss are improved. An excellent impact-resistant aromatic vinyl resin can be obtained, and the industrial significance of the present invention is extremely large.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Mikio Takeuchi 2--11-24 Tsukiji, Chuo-ku, Tokyo Japan Synthetic Rubber Co., Ltd. (56) References JP-A-61-143415 (JP, A) JP-A Sho 63-48317 (JP, A)

Claims (2)

(57) [Claims] 1. A method of polymerizing an aromatic vinyl compound in the presence of a styrene-butadiene-based block copolymer, wherein the styrene-butadiene-based block copolymer has a polystyrene equivalent weight average molecular weight (分子) and a number average The ratio of molecular weight (▲ ▼) (▲ ▼ / ▲ ▼)
1.20 or more, gel permeation chromatography (GPC)
(PM / ▲ ▼) of peak molecular weight (PM) obtained by the method and weight average molecular weight in terms of polystyrene (▲ ▼)
Is 1.02 or more, Mooney viscosity (ML _{1 + 4 at} 100 ° C) is 20-100, and the viscosity of a 5% by weight styrene solution measured at 25 ° C is 10-
A styrene-butadiene-based block copolymer having 100 centipoise, a total styrene content of 3 to 20% by weight, a block styrene content of 90% or more of the total styrene content, and a vinyl bond content of a butadiene portion of 13 to 30%; A method for producing an impact-resistant aromatic vinyl resin, comprising adjusting the average particle diameter of the block copolymer particles dispersed in the obtained resin to a range of 0.4 to 1.4 μm. Wherein the styrene - butadiene block copolymer, upon sequentially block copolymer of butadiene and styrene as an initiator an organolithium compound in a hydrocarbon solvent, (i) -SO ₃ K group or One or more anionic surfactants having an —OSO ₃ K group (K represents a potassium metal atom), and (ii) a general formula: CH ₂ ＣC ＝ CHR (where R is a hydrogen atom or 1 A styrene-butadiene block copolymer produced by coexisting at least one kind of a 1,2-diene compound represented by the following formula: Item (1).