JPH0649743B2 - Method for manufacturing impact resistant resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. TECHNICAL FIELD The present invention relates to a method for producing an impact resistant resin, and more specifically, in the presence of a rubber-like conjugated diene polymer and a small amount of a specific aromatic vinyl-conjugated diene block copolymer, By graft-polymerizing an aromatic vinyl compound and adjusting the dispersed rubber particles in the obtained resin to a specific particle size,
The present invention relates to a method for producing an impact resistant resin having excellent impact resistance and appearance characteristics.

b. Conventional Technology Generally, aromatic vinyl resins such as styrene resins are
It has many excellent properties such as ease of flow at the time of molding, transparency of the molded product, and good surface gloss, but the major drawback is inferior impact resistance.

As a method for improving this drawback, for example, a method of mechanically blending a rubber-like polymer in fat, 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 on the rubber-like polymer is generally a bulk polymerization method or a bulk-polymerization method.
It is carried out by a suspension polymerization method, for example, one using polybutadiene rubber as a rubber-like polymer and styrene as an aromatic vinyl compound is known as an impact-resistant polystyrene resin, and is a household electric appliance such as a television, a radio, a video and a cleaner. It is widely used as a material for housings and inner boxes of electric refrigerators. In that case, it is of course desirable that the surface impact is good, but at the same time, the surface gloss is good.

Generally, the impact resistance of the resin produced by the above method is improved by increasing the amount of the rubber-like polymer or increasing the particle size of the dispersed particles, but the surface gloss is deteriorated.

On the other hand, by reducing the amount of the rubber-like polymer or reducing the particle size of the dispersed rubber particles, the surface gloss is improved, but on the other hand, the impact resistance is significantly lowered.

As described above, since impact resistance and surface gloss are contradictory properties, it is difficult to obtain an impact-resistant aromatic vinyl resin having high impact resistance and good surface gloss.

Conventionally, as a method for improving the properties of impact-resistant aromatic vinyl-based resin, a method for improving the rubber-like polymer to be used (for example, Japanese Patent Publication No. 58-4934) or for making the particle size distribution of dispersed rubber particles specific (For example, JP-A-59-217712,
JP-A-60-130613) has been proposed.

Further, in general, for practical impact resistance, Izod impact strength alone is insufficient, and it is also necessary to have excellent falling weight impact strength.However, in conventional impact resistance aromatic vinyl resins, Izod impact strength, None of them showed satisfactory properties in simultaneously improving drop impact strength and surface gloss.

c. DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In view of such circumstances, the present inventors have earnestly aimed at obtaining an impact-resistant aromatic vinyl resin excellent in Izod impact strength, falling weight impact strength, and surface gloss. As a result of the study, in the presence of a small amount of a rubbery conjugated diene polymer and an aromatic vinyl-conjugated diene block copolymer having a specific structure, radical polymerization of an aromatic vinyl compound, and,
The inventors have found that the technical problem can be solved by adjusting the dispersed rubber particles in the obtained resin to have a specific particle size, and have reached the present invention.

d. Means for Solving the Problems That is, the present invention, a rubber-like conjugated diene-based polymer, the weight average molecular weight is 100,000 ~ 500,000, and the composition ratio of the aromatic vinyl compound and the conjugated diene is 35: 65 ~ 70. : 30
(A weight ratio) a mixture of the aromatic vinyl-conjugated diene block copolymer, the content of the aromatic vinyl-conjugated diene block copolymer in the mixture is 5 to 30 wt% conjugated diene Radical-polymerizing a monomer mainly composed of an aromatic vinyl compound in the presence of a system polymer, and the conjugated diene polymer particles dispersed in the obtained resin have a median particle diameter of 0.5 to 1.4 μm. The present invention provides a method for producing an impact resistant resin, which is characterized by adjusting the range to

The rubber-like conjugated diene-based polymer used in the present invention is mainly a polybutadiene rubber, which is generally obtained by polymerizing 1,3-butadiene with an organolithium compound as a catalyst and has a 1,4-cis bond content of 20 to 40. %, 1,2-
Low cis polybutadiene having a vinyl bond content of 10 to 40% and 1,4-cis bond content of 90 to 1, obtained by polymerizing 1,3-butadiene with a nickel or cobalt catalyst.
It is a high cis polybutadiene having a 1,2,5-vinyl bond content of 1 to 5%. Especially Mooney viscosity (ML _{1 + 4,100} ℃) is 20
˜70, 5% styrene solution viscosity (25 ° C.) of 30 to 200 can be preferably used.

A copolymer of a conjugated diene and another copolymerizable monomer can also be used.

Examples of the above-mentioned conjugated diene and other copolymerizable monomer include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, vinylethylbenzene, and vinylxylene, but preferably styrene. And generally obtained using an organolithium compound as a catalyst, the content of bound styrene is 5 to 35%, 1,4
-Cis bond content 20-40%, 1,2-vinyl bond content 10-
A 40% solution polymerized SBR can be preferably used.

The aromatic vinyl-conjugated diene block copolymer used in the present invention includes (AB) _n , (AB) _n- A,
Although various types of block copolymers such as (AB) _n X (n is an integer of 1 or more) can be used, among these, (A-
B) _n- type is preferable, and n = 1 is particularly preferable. This AB type diblock copolymer is obtained by sequentially polymerizing an aromatic vinyl compound and a conjugated diene compound using an organolithium compound according to a known method (for example, JP-A-36-19286). Can be obtained.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, vinylethylbenzene and vinylxylene, but preferably styrene and α-.
Methyl styrene and p-methyl styrene are preferred, and styrene is more preferred. Examples of the conjugated diene compound include 1,3-butadiene, 1,3-pentadiene, isoprene, 1,3-hexadiene, 2,4-hexadiene, 2,3-dimethyl-1,3-butadiene and 2-ethyl-1. , 3-butadiene, 1,3-pentadiene, and the like, and various branched conjugated diene compounds having 4 to 7 carbon atoms, preferably 1,3-butadiene, isoprene,
1,3-pentadiene, particularly preferably 1,3-butadiene.

The amount of the aromatic vinyl-conjugated diene block copolymer used is 5 to 30% by weight in the conjugated diene polymer (a mixture of a rubber-like conjugated diene polymer and an aromatic vinyl-conjugated diene block copolymer). is there. Preferably 6 to 25% by weight,
More preferably, it is 7 to 20% by weight. If it is less than 5% by weight, it is effective in improving the falling weight impact strength, but
The effect of improving Izod impact strength is not sufficient. On the other hand, if it exceeds 30% by weight, the shape of the dispersed rubber particles becomes unstable during the graft polymerization, so that only the one having inferior gloss can be obtained.

Aromatic vinyl-weight average molecular weight of the conjugated diene block copolymer is 100,000 ~ 500,000, preferably 150,000 ~ 45.
It is 0,000, more preferably 200,000 to 400,000. When the weight average molecular weight is less than 100,000, both the Izod impact strength and the falling weight impact strength are poor in improving effect. On the other hand, if the weight average molecular weight exceeds 500,000, the particle diameters of the dispersed rubber particles become uneven, and giant particles are likely to be generated, so that only those with poor gloss can be obtained.

In the aromatic vinyl-conjugated diene block copolymer,
The composition ratio of aromatic vinyl and conjugated diene is 35:65 to 70:30.
(Weight ratio). It is preferably 40:60 to 65:35, more preferably 45:55 to 60:40. When the amount of aromatic vinyl is less than 35% by weight, the effect of improving both Izod impact strength and falling weight impact strength is insufficient. On the other hand, when the amount of aromatic vinyl exceeds 70% by weight, the shape of dispersed rubber particles becomes unstable during graft polymerization, and only gloss is inferior.

In the present invention, the aromatic vinyl-conjugated diene block copolymer is used in a specific amount, and at the same time, the average particle diameter of the rubber particles dispersed in the obtained resin is 0.5 to 1.4 μm in median diameter. And need to. It is preferably 0.6 to 1.2 μm. When the median diameter is less than 0.5 μm, both Izod impact strength and falling weight impact strength are poor. When the median diameter exceeds 1.4 μm, only a resin having inferior surface gloss can be obtained, and the tensile strength sharply decreases, so that only a resin having a poor physical property balance can be obtained.

As described above, in order to adjust the particle size of the rubber particles, it is influenced by various factors such as the shape of the stirring device of the polymerization tank, the number of rotations of the stirrer, the stirring time, the polymerization temperature, etc., and should be uniquely determined. However, in general, the particle diameter can be reduced by stirring under the condition that stress is applied to the rubber during the graft polymerization, for example, by increasing the rotation speed.

Generally, in the above graft polymerization, since a rubber-like polymer is used, the viscosity of the polymerization system becomes very high and it is not easy to increase the stirring strength, but in the present invention, an aromatic compound having a specific structure is used. The presence of a specific amount of the vinyl-conjugated diene diblock copolymer has an advantage that the particle size of the resin obtained becomes small and a small particle size can be easily obtained.

Next, the present invention uses the above-mentioned specific conjugated diene-based polymer and graft-copolymerizes an aromatic vinyl compound to the polymer.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, p-methylstyrene, vinyltoluene, vinylnaphthalene, vinylethylbenzene, and vinylxylene, but preferably styrene,
α-Methylstyrene and p-methylstyrene, and more preferably styrene.

Regarding the mixing ratio of the conjugated diene polymer and the aromatic vinyl compound, the former is 3 to 25% by weight, preferably 5 to 15% by weight,
More preferably 7 to 13% by weight, the latter 97 to 75% by weight,
It is preferably 95 to 85% by weight, more preferably 93 to 87% by weight. If the amount of the conjugated diene polymer used is less than 3% by weight, the impact resistance of the resulting resin will be lowered, making it difficult to achieve the object of the present invention. Therefore, it becomes practically difficult to perform graft polymerization.

The method of radically copolymerizing the aromatic vinyl compound with the specific conjugated diene polymer is not particularly limited, but for example, bulk polymerization of an aromatic vinyl compound solution in which the conjugated diene polymer is dissolved is carried out. , Bulk polymerization-suspension polymerization are combined to carry out radical polymerization.

When radically polymerizing the conjugated diene-based polymer and the aromatic vinyl compound by bulk polymerization, the conjugated diene-based polymer is dissolved in the aromatic vinyl compound, and then a molecular weight modifier is added if necessary.

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

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

After dissolving these molecular weight regulators and lubricants in the above polymer solution, benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, methyl ethyl ketone peroxide, dicumyl peroxide, diisopropyl peroxydicarbonate, tertiary as an initiator. Butyl peroxyacetate, diethyl butyl peroxyisophthalate, 2,5-
Add dimethyl-2,5-di (t-butylperoxy) hexane or azobisisobutyronitrile,
The reaction is completed with stirring under an inert gas atmosphere at a reaction temperature of 60 to 200 ° C.

In bulk polymerization, it is also possible to initiate the polymerization by heat or light without using an initiator.

In the bulk polymerization reaction, it is usually preferable to effectively stir in the stage until the polymerization rate of the aromatic vinyl compound reaches about 30%, and particularly in the present invention, the dispersed rubber particle diameter is within the range of the present invention. It is necessary to adjust the agitation so that the polymerization rate of the aromatic vinyl compound is about
It is preferred to moderate the agitation after proceeding above 30%.

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

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

Next, in the case of radical polymerization by a combination of bulk polymerization-suspension polymerization, first, bulk polymerization is performed until about 10 to 45% by weight of the monomer (aromatic vinyl compound) is converted into a polymer, and then the reaction solution. Is dispersed in an aqueous solution in which a suspension stabilizer such as polyvinyl alcohol, polymethacrylic acid salt, and tricalcium phosphate is dissolved, and polymerization is completed at a reaction temperature of 60 to 160 ° C. while maintaining the suspension state. After the completion of the polymerization, the suspension stabilizer is sufficiently washed with water to remove and dried, and then the aromatic vinyl resin is recovered.

In the radical polymerization by the bulk polymerization or 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. ,
It may be replaced with an aliphatic vinyl compound such as methacrylonitrile, methyl acrylate, or methyl methacrylate.

In addition, the resins obtained by the above-mentioned polymerization methods include known antioxidants such as 2,6-di-tert-butyl-4-methylphenol and 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-octoxy. (Phenyl) benzothiazole; known lubricants such as paraffin wax, stearic acid, hydrogenated oil, stearamide, methylenebis stearamide, n-butyl stearate, ketone wax, octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride; Flame retardants such as antimony oxide, aluminum hydroxide, zinc borate, tricresyl phosphate, chlorinated paraffins, tetrabromobutane, hexabromobenzene, tetrabromobisphenol A; known antistatic agents such as stearoa Midopropyl dimethyl-β-hydroxyethyl ammonium nitrate; known colorants,
For example, titanium oxide, carbon black, and other inorganic or organic pigments; known fillers such as calcium carbonate, clay, silica, glass fibers, glass spheres, carbon fibers and the like can be added if 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% are parts by weight and% by weight, unless otherwise specified.

In addition, various measurements in the examples were as follows.

The microstructure of the polybutadiene rubber was measured by the infrared method (Morero method), and the viscosity of the styrene solution was measured by a Canon Fenske viscometer.

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

The molecular weight distribution of the styrene-butadiene block copolymer, Toyo Soda Industry Co., Ltd. HLC-802A type GPC,
The measurement was performed under the following conditions.

Column: Toyo Soda Kogyo Co., Ltd. column G-4000HXL Mobile phase: Tetrahydrofuran Sample concentration: 0.1% by weight Measurement temperature: 40 ° C Detector: Differential refractometer For the weight molecular weight, the molecular weight distribution obtained by the above measurement is used. Based on the product, manufactured by Waters, using a monodisperse styrene polymer, using a calibration curve previously obtained by GPC to determine the relationship between the molecular weight of the peak of the monodisperse styrene polymer and the count number of GPC, the styrene-butadiene block copolymer The weight average molecular weight of the polymer in terms of polystyrene was determined.

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

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

Tensile strength; 8 _oz injection molding machine, cylinder temperature 20
About the molded product obtained by molding at 0 ° C, ASTM D-638
It was measured according to.

Gloss; Cylinder temperature 200 ℃, using _8oz injection molding machine
The 60 ° reflection gloss of the molded product obtained by molding in accordance with ASTM D-523 was measured.

Drop weight impact strength; 8 _oz injection molding machine, cylinder temperature 200 ℃, molded product 40 mm × 80 mm × 30 mm square plate, 1 kg as the impact core, the energy when the sample cracked ( It is expressed as (height x weight weight).

Measurement of median particle size of dispersed rubber particles; resin pellets 1 to
2 grains are put in about 50 ml of dimethylformamide and left for about 3 hours. Next, add this dimethylformamide solution to the electrolyte (ISOTON II) and measure it with a Coulter counter to obtain an appropriate particle concentration. From the particle size distribution obtained,
A median diameter of 50% was calculated.

The properties of the polybutadiene rubber and styrene-butadiene block copolymer used in Examples and Comparative Examples are shown in Tables 1 and 2.

Example 1 A mixture of polybutadiene, a styrene-butadiene block copolymer, and styrene having the compositions shown in Table 3 was stirred at room temperature for 8 hours and uniformly dissolved. The volume of this solution is 5
Transfer to a polymerization reactor equipped with a stirrer, and add white mineral oil 1
Part, tert-dodecyl mercaptan 0.04 part and benzoyl peroxide 0.04 part were added and polymerized at 95 ° C. until the polymerization rate of styrene was about 25%. The dispersed rubber particle diameter was adjusted by the stirring rotation speed so as to be 0.7 μm.

Then, 2,5-dimethyl 2,5 per 100 parts of this solution
-0.08 parts of di (t-butylperoxy) hexane was added, and tricalcium phosphate 2 was added as a suspension stabilizer.
And 150 parts of water containing 0.005 part of sodium dodecylbenzenesulfonate as a surfactant were added, and the solution was suspended with stirring. Stir this suspension mixture at 120 ° C.
Polymerization was carried out by heating at 140 ° C for 2 hours and at 160 ° C for 2 hours.

The obtained bead-shaped resin was filtered, washed with water, dried and pelletized using an extruder. The impact-resistant styrene-based resin thus obtained was injection-molded, and test pieces for measuring physical properties were measured.

Table 3 shows the measurement results of each physical property.

Examples 2 to 4 and Comparative Examples 1 to 2 In the same manner as in Example 1, polybutadiene rubber having the composition shown in Table-3, styrene-butadiene block copolymer,
An impact-resistant polystyrene resin was obtained from a monomer mixture composed of styrene. Dispersed rubber particle size is 0.5-1.4 μm
The stirring speed was adjusted so that

Table 3 shows the measurement results of each physical property.

As is clear from the results of Examples 1 to 4 shown in Table-3,
It can be seen that the resin of the present invention obtained by using the specific amount of the specific styrene-butadiene block copolymer is excellent in any of Izod impact strength, falling weight impact strength and gloss. On the other hand, as is clear from Comparative Example 1 shown in Table-3, when the amount of the styrene-butadiene block copolymer used is less than the range of the present invention, the Izod impact strength is poor and the styrene-butadiene block copolymer is poor. It can be seen that the resin obtained in Comparative Example 2 in which the proportion of the polymer used exceeds the range of the present invention has poor gloss.

Comparative Examples 3 to 6 In the same manner as in Example 1, polybutadiene rubber having the composition shown in Table-4, styrene-butadiene block copolymer,
A monomer mixture composed of styrene was polymerized by adjusting the stirring rotation speed so that the median particle diameter of the dispersed rubber particles was 0.4 to 1.7 μm to obtain an impact-resistant polystyrene resin.

Table 4 shows the measurement results of each physical property.

As is apparent from Table 4, even when a specific styrene-butadiene block copolymer is used in a limited amount within the range of the present invention, Comparative Example 3 in which the median particle diameter of the dispersed rubber particles is less than the range of the present invention. In Comparative Example 4, the Izod impact strength and the falling weight impact strength are inferior, and the median particle diameter of the dispersed rubber particles exceeds the range of the present invention, Comparative Example 4 is inferior in gloss and tensile strength.

From Table 3 and Table 4, when the specific styrene-butadiene block copolymer of the present invention is used, the median particle diameter of the dispersed rubber particles is within the range of the present invention, and the median particle diameter of the dispersed rubber particles is Although the impact resistance is excellent even when the value is small, on the other hand, in Comparative Examples 5 and 6 in which the specific styrene-butadiene block copolymer of the present invention is not used, when the median particle diameter of the dispersed rubber particles is decreased, the impact resistance is improved. It can be seen that it is significantly reduced.

Examples 5 to 6 and Comparative Examples 7 to 10 The styrene-butadiene block copolymer was composed of the polybutadiene rubber, the styrene-butadiene block copolymer, and the styrene having the composition shown in Table 5 in the same manner as in Example 1. The monomer mixture was polymerized by controlling the stirring rotation speed so that the dispersed rubber particles had a median particle diameter of 0.5 to 1.4 μm to obtain an impact-resistant polystyrene resin.

The measurement results of each physical property are shown in Table-5.

As is clear from Table 5, the resins of Examples 5 to 6 in which the weight average molecular weight of the styrene-butadiene block copolymer and the amount of bound styrene are within the scope of the present invention are Izod impact strength, falling weight impact strength, and gloss. It can be seen that both are excellent.

On the other hand, when the resin of Comparative Example 7 in which the weight average molecular weight of the styrene-butadiene block copolymer is less than the range of the present invention is used, both the Izod impact strength and the falling weight impact strength are inferior. It can be seen that the resin of Comparative Example 8 exceeding the range has a poor gloss.

Further, Comparative Example 9 in which the composition ratio of styrene and butadiene in the styrene-butadiene block copolymer is less than the range of the present invention.
Shows that both Izod impact strength and falling weight impact strength are inferior, and Comparative Example 10, which exceeds the range of the present invention, has an unstable shape of dispersed rubber particles and is inferior in gloss.

Example 7, Comparative Example 11 A polybutadiene rubber having the composition shown in Table 6 and a styrene-butadiene block copolymer were prepared in the same manner as in Example 1 except that the type of polybutadiene rubber used was changed to PBD-B. An impact-resistant polystyrene resin was obtained from a monomer mixture containing styrene.

The measurement results of each physical property are shown in Table-6.

As is clear from Table-6, the specific styrene-butadiene block copolymer of the present invention was used in a limited small amount range by changing the kind of polybutadiene rubber used, and Izod impact strength and falling weight impact strength It can be seen that it is excellent in both gloss and gloss.

Example 8 and Comparative Example 12 The rubber-like polymer used was solution-polymerized SBR (T manufactured by Asahi Kasei Corporation)
ofdene-2000: bonded styrene 25%, Mooney viscosity 46, solution viscosity (5% styrene cps) 52, 1,2-vinyl bond content 13%, 1,4-cis bond content 34%) A solution-polymerized SB having the composition shown in Table 7 in the same manner as in Example 1
An impact-resistant polystyrene resin was obtained from a monomer mixture of R, styrene-butadiene block copolymer, and styrene.

The results of measuring the physical properties of the obtained impact resistant polystyrene resin are shown in Table 7.

As is clear from Table 7, even if the rubber-like polymer used was replaced with a styrene-butadiene copolymer rubber, the one obtained by using the specific amount of the specific styrene-butadiene block copolymer of the present invention had an Izod impact. Strength, drop weight impact strength,
It can be seen that the gloss is excellent.

f. Effects of the Invention According to the present invention, a specific aromatic vinyl-conjugated diene block copolymer is used as a part of the conjugated diene polymer, and the median particle diameter of the conjugated diene polymer particles dispersed in the resin is By controlling within a specific range, an impact-resistant aromatic vinyl resin excellent in impact resistance and appearance characteristics can be obtained, and its industrial significance is extremely large.

Claims (1)

[Claims] 1. A rubber-like conjugated diene polymer, a weight average molecular weight of 100,000 to 500,000, and a composition ratio of an aromatic vinyl compound and a conjugated diene of 35:65 to 70:30 (weight ratio). A mixture with an aromatic vinyl-conjugated diene block copolymer, wherein the content of the aromatic vinyl-conjugated diene block copolymer in the mixture is 5 to 30% by weight in the presence of a conjugated diene polymer Radical polymerization of a monomer mainly composed of an aromatic vinyl compound, and adjusting the median particle diameter of the conjugated diene polymer particles dispersed in the obtained resin to the range of 0.5 to 1.4 μm. A method for producing an impact resistant resin, comprising: