JPH0699531B2 - Method for producing impact resistant styrene resin - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention provides a shock-resistant styrenic resin having impact resistance and improved appearance characteristics by uniformly dispersing a rubber-like substance in a granular form. The present invention relates to a manufacturing method of.

[Prior Art] Copolymer resin of acrylonitrile, butadiene and styrene, that is, ABS resin, has excellent oil resistance, rigidity, heat resistance and impact resistance, and also has a good appearance, so it is used for various electrical products, automobile parts, Although it is used as a housing product, it is unavoidable that the cost will increase because acrylonitrile is used as a raw material, and there is a limit to its use as a general-purpose material.

Therefore, there has been proposed a method for producing an impact-resistant styrene resin by polymerizing styrene stepwise in the presence of a rubber-like substance without using an acrylic monomer (Japanese Patent Publication No. No. 7343), the impact-resistant styrene resin thus obtained is inferior in appearance and rigidity and is unsuitable as a material for household electric appliances and audio equipment.

Further, in the production of a rubber-modified styrene-based polymer resin, it has been attempted to improve the physical properties by adding a polymerization catalyst and a chain transfer agent in several divided portions (Japanese Patent Laid-Open Publication No. Sho.
57-141414), there is a limit to the improvement of impact resistance and other physical properties by this method, and a resin comparable to the ABS resin cannot be obtained.

[Problems to be Solved by the Invention] The present invention has excellent physical properties comparable to ABS resin without using an acrylonitrile-based monomer, that is, excellent impact resistance, heat resistance, rigidity, and good appearance characteristics. The present invention has been made for the purpose of providing a method for continuously producing a rubber-modified styrenic resin exhibiting processing fluidity.

[Means for Solving Problems] As a result of various studies on the method for obtaining a rubber-modified styrenic resin having excellent physical properties, the present inventors have found that a styrene-based monomer is present in the presence of a rubber-like substance. By stepwise polymerizing while controlling the polymerization rate under specific conditions,
It was found that a rubber-modified styrenic resin having a physical property comparable to or excellent in ABS resin can be obtained without containing an acrylonitrile component, and the present invention has been completed based on this finding.

That is, the present invention, impact resistance by continuously polymerizing a styrenic monomer containing a rubber-like substance in the presence of a solvent, using an organic oxide or organic peroxide and a chain transfer agent as a polymerization initiator. In the production of styrene-based resin, (a) the amount of the solvent in the raw material mixture should be 25% by weight or less and the amount of the rubber-like substance should be 3 to 12% by weight, (b) 0.001 per 100 parts by weight of the raw material mixture. ~ 0.20 parts by weight of organic peroxide is used, at least a part of which is added to the raw material mixture at the start of the polymerization, and (c) in the first step, 0.1 to 1.5 times the weight of the rubber substance is produced. (D) In the second step, continue bulk polymerization while stirring until the polymerization conversion rate of all monomers reaches 18-40%, and convert the rubber-like substance into particles in the polymer. Disperse,
And (e) Impact-resistant styrene-based resin, characterized in that it is polymerized by bulk polymerization and / or suspension polymerization in the third stage until a styrene-based polymer having a rubber-like substance content of 3 to 20% by weight is obtained. And a monomer mixture mainly comprising a styrene monomer containing a rubber-like substance in the presence of a solvent, using an organic oxide as a polymerization initiator, and a chain transfer agent. In the case of producing impact resistant styrene resin by continuously polymerizing in the presence of (a), (a) the amount of the solvent in the raw material mixture is 25% by weight or less, and the amount of the rubber-like substance is 3 to 12% by weight. (B) 0.001 to 0.20 parts by weight of organic peroxide is used per 100 parts by weight of the raw material mixture, and at least a part of the organic peroxide is added to the raw material mixture at the start of polymerization, (c) the raw material in the first step Decomposition of organic peroxides per 100 parts by weight of the mixture When (parts by weight) of the X _1, amount of the chain transfer agent (parts by weight) was Y _1, was added such that _{1.0 ≦ X 1 / Y 1 ≦} 3.0 by weight of the rubber material 0.1-1.5 Bulk polymerization is carried out until twice as many polymers are produced. (D) In the second stage, the total amount of the raw material mixture is 10
Decomposition amount (parts by weight) of organic peroxide per 0 parts by weight is X ₂ ,
When the added amount (parts by weight) of the chain transfer agent is Y ₂ , add it so that 1.0 ≦ X ₂ / Y ₂ ≦ 4.5 and stir until the polymerization conversion rate of all monomers is 18-40%. By continuing the bulk polymerization to disperse the rubber-like substance into particles in the polymer, and (e) by the bulk polymerization and / or suspension polymerization in the third step, the rubber-like substance content of 3 to 20% by weight is obtained. It is intended to provide a method for producing an impact-resistant styrene-based resin, which comprises polymerizing until a styrene-based polymer is obtained.

The styrene-based monomer used in the production method of the present invention,
For example, styrene, vinyltoluene, p-methylstyrene, t-butylstyrene, α-methylstyrene and the like.

Next, as the rubber-like substance used in the present invention, for example, polybutadiene, polyisoprene, styrene-butadiene random copolymer, styrene-butadiene block copolymer, styrene-butadiene-styrene block copolymer, chloroprene rubber, Examples include styrene-isoprene copolymer.

These may be used alone or in combination of two or more.

It is necessary to use these rubber-like substances with a concentration of 3 to 12% by weight in the raw material solution.

If this concentration is 3% by weight or less, the desired impact resistance cannot be obtained, and if it is 12% by weight or more, the solution viscosity becomes extremely high, and it becomes difficult to feed the raw material.

Although the present invention is carried out in the presence of a solvent, any solvent can be used as long as it has a high solubility in the reaction product. Particularly, aromatic hydrocarbons such as toluene, xylene, and ethylbenzene, either alone or as a mixture of two or more, are preferable.

Further, other solvents such as aliphatic hydrocarbons and dialkyl ketones may be used in combination with aromatic hydrocarbons within a range that does not impede the dissolution of the polymerization product from the rubber-like substance and the styrene-based monomer. it can.

It is necessary to use these solvents in the range of 25% by weight or less. If the amount used exceeds 25% by weight, the polymerization rate is remarkably reduced, the impact resistance of the obtained resin is greatly reduced, and the recovery energy of the solvent is large, resulting in poor economy, which is not preferable.

These solvents may be added after the progress of polymerization and the viscosity of the reaction liquid becomes high, or may be added from the start of the polymerization. It is preferable to add 5 to 15% by weight prior to the polymerization in terms of quality uniformity and polymerization temperature control.

Examples of the organic peroxide used as a polymerization initiator in the present invention include 2,2-bis (t-butylperoxy) butane, 2,2-bis (t-butylperoxy) octane and 1,1-bis (t -Butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl, 4,4-bis (t-butylperoxy)
Peroxyketals such as barrate, di-t-butyl peroxide, t-butylcumyl peroxide, di-cumyl peroxide, α, α′-bis (t-butylperoxyisopropyl) benzene, 2,5-dimethyl-2, 5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-
Butylperoxy) hexyne-3 and other dialkyl peroxides, acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, decanoyl peroxide, lauroyl peroxide, 3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, 2,
Diacyl peroxides such as 4-dichlorobenzoyl peroxide and m-toluoyl peroxide, di-isopropyl peroxydicarbonate, di-2-ethylhexyl peroxydicarbonate, di-n-propyl peroxydicarbonate, di-myristyl peroxydicarbonate, di- -2-ethoxyethyl peroxydicarbonate,
Di-methoxyisopropyl peroxydicarbonate,
Peroxydicarbonates such as di (3-methyl-3-methoxybutyl) peroxydicarbonate, t-butylperoxyacetate, t-butylperoxyisobutyrate,
t-Putyl peroxypivalate, t-Putyl peroxy neodecanoate, cumyl peroxy neodecanoate,
t-Putylperoxy-2-ethylhexanoate, t-Butylperoxy-3,5,5-trimethylhexanoate, t-Putylperoxynourate, t-Putylperoxybenzoate, Di-t-Putylperoxyisophthalate, 2,5-
Dimethyl-2,5-di (benzoylperoxy) hexane,
Peroxyesters such as t-butylperoxydiisopropyl carbonate, acetyl ascent peroxide, methyl ethyl ketone peroxide, cyclohexanone peroxide, 3,3,5-trimethylcyclohexanone peroxide, ketone peroxides such as methylcyclohexanone peroxide, t-butyl hydroperoxide, cumene hydro Hydroperoxides such as peroxides, di-isopropylbenzene hydroperoxide, p-methane hydroperoxide, 2,5-dimethylhexane-2,5-dihydroperoxide, 1,1,3,3-tetramethyl-butylhydroperoxide .

These may be used alone or in combination of two or more.

In the present invention, the amount of the organic peroxide to be used is 0.001 to 0.20 parts by weight per 100 parts by weight of the raw material mixture, and it is necessary to add a part thereof at the start of the polymerization.

In the first step of the production method of the present invention, the styrene-based monomer is graft-polymerized to the rubber-like substance in a weight range of 0.1 to 1.5 times, preferably 0.3 to 1.2 times.

In the first stage, the polymerization is carried out so that the rubber-like substance is below the critical polymerization conversion rate at which it is made into particles by the phase transition phenomenon.

In the first stage, usually 50 to 140 ° C, preferably 70 to 130
Polymerization is preferably carried out while maintaining a constant temperature in the temperature range of ° C.

At least a part of the organic peroxide added to the production method of the present invention may be added at the start of polymerization, and the rest may be added in the first stage, or the second stage or It may be added at a later stage.

Then, in the second stage, the reaction mixture obtained in the first stage is mixed with 50
The polymerization reaction is allowed to proceed continuously at a temperature of up to 160 ° C., preferably 60 to 150 ° C., and the polymerization conversion rate is 18 to 40%.

At this time, it is necessary to stir the rubber-like substance so that the finally obtained pellets have an average rubber particle size of 0.5 to 1.5 μm. The weight ratio of the polymer to the rubber-like substance in the system in the second stage was 16 or more,
At this stage, a phase transition occurs, and almost all the phases of the rubber-like substance are made into particles.

In the first step and the second step, as antioxidants, hindered phenols, hindered bisphenols, hindered trisphenols, etc., such as 2,6-di-t-butyl-4-methylphenol , Stearyl-β- (3,5-di-
t-Butyl-4-hydroxyphenyl) propionate can be added.

In the production method of the present invention, the polymerization mixture of the second stage obtained as described above is further polymerized in the third stage until a styrene polymer having a rubber-like substance content of 3 to 20% by weight is obtained. .

The polymerization reaction system in the present invention is carried out by a bulk polymerization method in the first step and the second step, but the third step may be either bulk polymerization or suspension polymerization or a combination of both.

The first step, the second step, and the third step in the present invention may be carried out using one reaction tank each, or each step may be carried out in two or more reaction tanks.

Next, when an organic peroxide and a chain transfer agent are used as the polymerization initiator of another invention, the chain transfer agent is a mercaptan, an α-methylstyrene linear dimer, or a terpinolene.

In the method of the present invention, it is advantageous that the chain transfer agent is dividedly added in each step, and the addition amount is selected in relation to the decomposition amount of the organic peroxide used as the polymerization initiator, and polymerization is advantageously performed.

That is, the first amount is based on 100 parts by weight of the raw material mixture
The addition amount Y ₁ (parts by weight) of the chain transfer agent in the step and the addition amount Y ₂ (parts by weight) of the chain transfer agent in the second step are selected within the following ranges.

1.0 ≦ X ₁ / Y ₁ ≦ 3.0 1.0 ≦ X ₂ / Y ₂ ≦ 4.5 where X ₁ and X ₂ are the decomposition amount per 100 parts by weight of the raw material mixture of the organic peroxide in the first step and the second step, respectively. (Parts by weight). For example, as the organic peroxide, 1,1-
When 0.04 parts by weight of bis (t-butylperoxy) -3,3,5-trimethylcyclohexane was charged in the first stage,
The amount of the organic peroxide decomposed in the step and the second step is
It is calculated by the following formula.

However, Kd is 1,1-bis (t-butylperoxy) -3,3,
Decomposition rate constant of 5-trimethylcyclohexane (mol / ・
hr · ° K) and the reaction temperature is T (° K), it can be calculated according to the following formula.

Kd = 6.969 × 10 ¹⁸ exp (−16720 / T) Further, θ is the residence time (hr).

Regarding the above, the reaction temperature of the first step was 99 ° C, the second
The reaction temperature in the step was 115 ° C., and the residence time was 1.2 hours in all calculations.

In the present invention, by selecting such reaction conditions, it is possible to obtain a rubber-modified styrenic resin having more excellent impact resistance and appearance characteristics.

According to the method of the present invention, the rubber-like substance content is 3 to 20% by weight,
It has an average rubber particle size of 0.5 to 1.5 μm, a rubber particle size distribution of 1.2 to 1.4, a gel content of 14 to 53% by weight, and a swelling degree of 6 to 14, and is excellent in impact resistance, processing fluidity, heat resistance and rigidity, and A rubber-modified styrenic resin exhibiting good surface gloss can be obtained.

The rubber-modified styrenic resin thus obtained is blended with an antioxidant, a colorant, a lubricant, a filler, a release agent, a plasticizer, an antistatic agent, etc., if desired, and used for various purposes. It

EFFECTS OF THE INVENTION According to the present invention, without containing an acrylonitrile component,
It is possible to obtain a rubber-modified styrene-based resin that has physical properties comparable to or better than ABS resin, that is, a rubber-modified styrene-based resin that has an excellent overall quality balance such as impact resistance, appearance characteristics, processing fluidity, heat resistance and rigidity. It can be widely used in home appliances, audio equipment, etc.

[Examples] The present invention will be described in more detail with reference to Examples.

In the examples and comparative examples, the following measuring methods were used.

(1) Measurement of dispersed particle size A transmission electron micrograph (magnification of 10,000) of an ultrathin section method of a resin was taken, and dispersed particles in the photograph were about 800-2,000.
It is determined by measuring the number of individual particles.

Since the dispersed particles shown in the electron micrograph are not perfectly circular, the particle diameter is calculated by the following equation by measuring the particle diameter in the longitudinal direction a and the particle diameter in the short width direction b.

Average particle size Ds (μ) = ΣniDi ³ / ΣniDi ² Particle size distribution Ds / Dn = (ΣniDi ³ / ΣniDi ² ) / (ΣniDi / Σni) where ni is the number of dispersed particles having the particle size Di.

(2) Gel amount and degree of swelling Add 200 ml of toluene to a resin of 2 g and shake vigorously for 3 hours to dissolve or swell. Next, the gel is settled by a centrifuge, the supernatant is discarded by decantation, and the settled gel is weighed. The toluene swollen gel thus obtained was naturally dried at room temperature for 24 hours, then at 60 ° C. for 3 to 5 mmHg.
Dry under reduced pressure for 6 hours, cool in a desiccator and weigh. The gel content is given in wt% by dividing the weight of dry gel by the weight of resin. The swelling index is indicated by a quotient obtained by dividing the weight of the toluene swelling gel by the weight of the dry gel.

(3) Melt flow rate (g / 10 minutes) Measured according to JIS K 7210 (200 ° C, 5 kg).

(4) Izod impact strength Measured according to JIS K 7110 (notched).

(5) Flexural modulus Measured according to ASTM D 790.

(6) Gloss Measured according to JIS Z 8741 (incident angle 60 °).

(7) Heat distortion temperature Measured according to JIS K 6871.

Example 1 The following mixture was mixed with the first of 13 at a feed rate of 10 / hour:
Liquid is continuously fed to the polymerization vessel (first stage).

Low cis polybutadiene rubber (Asahi Kasei, trade name; NF35A
S: Mooney viscosity of 35 at 100 ° C) 7.5 parts by weight Styrene 87.5 parts by weight Ethylbenzene 5.0 parts by weight Total 100 parts by weight 1,1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane 0.040 parts by weight n-dodecyl mercaptan 0.013 parts by weight mineral oil 0.5 parts by weight Antioxidant (Ciba-Geigy Co .: trade name: Irganox 1076) 0.070 parts by weight The first polymerization vessel is set to a temperature of 93 ° C.
It was 0.53 times (weight ratio) with respect to the amount of rubber charged. Observation with a phase-contrast microscope revealed black polystyrene particles in the white rubber continuous phase, and the rubber phase had not yet been formed into particles.

Next, a mixture of this rubber graft solution and n-dodecyl mercaptan (0.030 parts by weight) is continuously fed to the 13th second polymerization vessel (second stage). Adjust the rubber particle size at a temperature of 112 ° C and a stirring speed of 300 rpm. The polymerization conversion rate at the outlet was 24.3%.

This product was further fed to a third polymerization vessel 19 and then a fourth polymerization vessel 20 and polymerized at a temperature of 128 to 180 ° C. The polymerization conversion rate at the outlet was 90.4%.

The obtained polymerization reaction liquid was introduced into the degassing step and was subjected to a conventional method,
Volatile components were removed to obtain cylindrical pellets.
Next, this pellet was injection-molded and the physical properties of the molded product were measured. The results are shown in Table 1.

Examples 2 and 3 The same operation as in Example 1 was carried out except that the amount of n-dodecyl mercaptan added and the temperature in the first polymerization vessel (first stage) were changed as shown in Table 1.

The physical properties of the injection-molded product of this product are shown in Table 1.

Example 4 As a rubber-like substance, high-cis polybutadiene (BR15HB manufactured by Ube Industries, Ltd .: having a Mooney viscosity of 40 at 100 ° C. of 40) was used. The same procedure as in Example 1 was carried out except that the stirring speed was changed. The physical properties of the obtained injection-molded product were measured, and the results are shown in Table 1.

Example 5 Example 5 was repeated except that the amount of the rubber-like substance charged was changed as shown in Table 1. The physical properties of the obtained resin injection-molded product were measured, and the results are shown in Table 1.

Example 6 In Example 5, the polymerization reaction liquid obtained in the second polymerization vessel was sent to the third polymerization vessel 6 in the figure. The polymerization conversion rate was 41.3% at a polymerization temperature of 131 ° C.

100 parts by weight of this polymer was suspended in 150 parts by weight of water containing 3 parts by weight of tricalcium phosphate and 0.02 parts by weight of sodium dodecylbenzenesulfonate, and 0.3 parts by weight of benzoyl peroxide and di-t were added to this suspension. -Butyl peroxide (0.05 parts by weight) was added, and the mixture was polymerized at 80 ° C for 2 hours, 110 ° C for 2 hours, and 140 ° C for 3 hours to complete the polymerization. The obtained suspended particles were separated by filtration, dried, and injection-molded as pellets with an extruder to measure physical properties.

The results are shown in Table 1.

Example 7 Charge amount of rubber-like substance and charge amount of solvent and organic peroxide species, charge amount, charge time and chain transfer agent charge amount, charge time, mineral oil charge amount and second polymerization reactor temperature, stirring speed, polymerization conversion Example 1 was repeated except that the rate was changed as shown in Table 1. The physical properties of the obtained resin injection-molded product were measured, and the results are shown in Table 1.

Example 8 In Example 7, the polymerization reaction liquid obtained in the second polymerization vessel was fed to the third polymerization vessel 6. At a temperature of 131 ° C, the polymerization conversion rate was 41.3%.

100 parts by weight of this polymer was suspended in 150 parts by weight of water containing 3 parts by weight of tricalcium phosphate and 0.02 parts by weight of sodium dodecylbenzenesulfonate, and 0.3 parts by weight of benzoyl peroxide and di-t were added to the suspension. -Butyl peroxide
Add 0.05 parts by weight, 80 ° C for 2 hours, 110 ° C for 2 hours,
Polymerization was further completed at 140 ° C. for 3 hours to complete the polymerization.

The obtained suspended particles were separated by filtration, dried, pelletized by an extruder and injection-molded to measure the physical properties. The results are shown in Table 1.

Example 9 Charge amount of rubber-like substance, solvent charge amount, organic peroxide species, charge amount, charge time, chain transfer agent charge amount, charge time, mineral oil charge amount and temperature of second polymerization vessel, stirring speed,
Example 1 except that the polymerization conversion was changed as shown in Table 1.
I went the same way. The physical properties of the obtained resin injection-molded product were measured, and the results are shown in Table 1.

Example 10 A rubbery substance was used as a styrene-butadiene copolymer (manufactured by Asahi Kasei Corp., trade name; Tafden 2000A: 5% styrene solution 3).
Same as Example 1 except that the solution viscosity at 0 ° C. was 50 centistokes rubber content 75% by weight). The physical properties of the obtained resin injection-molded product were measured, and the results are shown in Table 1.

Comparative Example 1 In Example 1, the charged amount of n-dodecyl mercaptan was 0.
The raw material of 030 parts by weight was passed through the first polymerization vessel,
Liquid is sent to the second polymerization vessel. Stirring speed 3 at temperature 118 ° C
The speed was set to 00 rpm, and the obtained polymerization product was 3.2 times (weight ratio) the amount of the charged rubber. Observation with a phase-contrast microscope revealed white rubber particles in the black polystyrene continuous phase, which were formed into particles.

The subsequent polymerization steps were the same as in Example 1. The physical properties of the resulting resin injection-molded product were measured and are shown in Table 2.

Comparative Example 2 Same as Example 1 except that the temperature of the first polymerization vessel was 114 ° C. The polymerization product obtained in the first polymerization step was 1.93 times (weight ratio) the amount of the charged rubber. Observation with a phase-contrast microscope revealed white rubber particles in the continuous phase of black polystyrene, which were formed into particles. The physical properties of the resulting resin injection-molded product were measured and are shown in Table 2.

Comparative Example 3 The temperature of the second polymerization reactor was 123 ° C., and the polymerization conversion rate at the outlet was 44.8.
The same procedure was performed as in Example 3 except that the percentage was%. The physical properties of the resulting resin injection-molded product were measured and are shown in Table 2.

Comparative Example 4 The temperatures of the first polymerization reactor and the second polymerization reactor were 117 ° C and 117 ° C, respectively.
The ratio of the polymerization product obtained in the first polymerization reactor to the amount of the charged rubber was 2.96 (weight ratio), and the same as in Example 1 except that the polymerization conversion rate at the outlet of the second polymerization reactor was 45.2%. Went to. The physical properties of the obtained resin injection-molded product were measured and are shown in Table 2.

Comparative Example 5 The procedure of Example 6 was repeated except that the amount of rubber charged was 2.0% by weight. The physical properties of the obtained resin injection-molded product were measured and are shown in Table 2.

Comparative Example 6 As the rubber-like substance, low cis polybutadiene (manufactured by Asahi Kasei Corp., trade name; NF55A, Mooney viscosity 55) was used.
Charged amount is 3% by weight, and ethylbenzene charged amount is 9.
The content was 7% by weight, 0.05 parts by weight of n-dodecyl mercaptan and 4.7 parts by weight of mineral oil were added, and the reaction was carried out by so-called thermal polymerization without adding an organic peroxide. At this time, the temperature of the first polymerization vessel was 103 ° C., and the ratio of the obtained polymerization product to the charged rubber amount was 1.47 (weight ratio). Then, the temperature of the second polymerization vessel was 130 ° C., and the stirring speed was 300 rpm. The polymerization conversion rate at the outlet of the reaction tank is
It was 25.3%.

The subsequent steps were performed in the same manner as in Example 1. The physical properties of the obtained resin injection-molded product were measured and are shown in Table 2.

Comparative Example 7 The procedure of Comparative Example 1 was repeated except that a styrene-butadiene copolymer (trade name: Tuffden 2000A) was used as the rubber-like substance. The physical properties of the obtained resin injection-molded product were measured and are shown in Table 2.

Comparative Example 8 The amount of the rubber-like substance charged was 6.4% by weight, the amount of ethylbenzene charged was 8.0 parts by weight, and the mineral oil was 2.0 parts by weight. Furthermore, organic peroxide and a chain transfer agent were not added, and so-called thermal polymerization was performed. It was made to react.

The ratio of the polymerization product in the first polymerization vessel to the charged amount of the rubber-like substance was 1.05 times (weight ratio), the stirring speed of the second polymerization vessel was 450 rpm, the temperature was 130 ° C, and the polymerization conversion rate at the outlet was The same procedure as in Example 1 was performed except that the amount was 26.5%. The physical properties of the resulting resin injection-molded product were measured and are shown in Table 2.

Comparative Example 9 At a feed rate of 10.8 / hour, the following mixture was continuously fed directly to the second polymerization reactor 13 without passing through the first polymerization reactor.

Rhocis polybutadiene [Asaple Chemical Co., Ltd .: trade name; Asaprene 700A: Mooney viscosity (100 ° C)] 6.0 parts by weight Styrene 55.5 parts by weight Acrylonitrile 18.5 parts by weight (weight ratio with styrene 75/25) Ethylbenzene 20.0 parts by weight Total 100.0 Parts by weight benzoyl peroxide 0.025 parts by weight 2,6-di-t-butylphenol 0.020 parts by weight n-dodecyl mercaptan 0.030 parts by weight antioxidant (manufactured by Ciba-Geigy: trade name; Irganox 1076) 0.070 parts by weight In this case, the temperature is 111 ° C. Then, the stirring speed is set to 220 rpm and the rubber particle size is adjusted. The polymerization conversion rate at the outlet was 26.8%.

The product was further fed to a third polymerization vessel of 19 and then to a fourth polymerization vessel of 20, and polymerized at a temperature of 120 to 170 ° C. The conversion rate at the outlet was 73.2%.

The obtained polymerization reaction liquid is passed through a devolatilization step, and in a conventional manner,
Volatile components were removed to obtain cylindrical pellets.
The physical properties of the obtained pellets and the physical properties of the injection molded product were measured, and the results are shown in Table 2.

Comparative Example 10 The procedure of Comparative Example 9 was repeated, except that a styrene-butadiene copolymer (trade name: Tuffden 2000A) was used as the rubber-like substance and the amount of benzoyl peroxide charged was 0.02 part by weight. The polymerization conversion rate at the outlet of the second polymerization vessel was 26.2%.
Met. The physical properties of the obtained resin injection molded product are measured,
It is shown in Table 2.

Comparative Example 11 As a rubber-like substance, a styrene-butadiene copolymer [manufactured by Asahi Kasei Corporation: trade name; Califlex TR-1102: solution viscosity of 25% toluene solution at 25 ° C., 1200 centistokes,
A rubber content of 72% by weight was used, and the procedure of Comparative Example 9 was repeated except that the temperature of the second polymerization vessel, the stirring speed, and the polymerization conversion rate were changed as shown in Table 2. The outlet polymerization conversion rate of the second polymerization vessel was 29.4%. The physical properties of the obtained resin injection molded product were measured and are shown in Table 2.

Comparative Example 12 In Example 8, the amount of chain transfer agent charged and the ratio of the polymerization product and the rubber-like substance reacted by so-called thermal polymerization without adding an organic peroxide are shown in Table 2. I changed it. The physical properties of the resulting resin injection-molded product were measured and are shown in Table 2.

Claims (2)

[Claims] 1. A method for producing an impact-resistant styrene resin by continuously polymerizing a styrene monomer containing a rubber-like substance in the presence of a solvent, using an organic peroxide as a polymerization initiator, (A) The amount of the solvent in the raw material mixture is 25% by weight or less, and the amount of the rubber-like substance is 3 to 12% by weight, (b) 0.001 to 0.20 part by weight of organic peroxide per 100 parts by weight of the raw material mixture. And at least a part thereof is added to the raw material mixture at the start of the polymerization, and (c) bulk polymerization is carried out until a polymer of 0.1 to 1.5 times the weight of the rubber substance is produced in the first step. ) Further, in the second step, the bulk polymerization is continued while stirring until the polymerization conversion rate of all the monomers reaches 18 to 40%, and the rubber-like substance is dispersed in the polymer into particles.
And (e) Impact-resistant styrene-based resin, characterized in that it is polymerized by bulk polymerization and / or suspension polymerization in the third stage until a styrene-based polymer having a rubber-like substance content of 3 to 20% by weight is obtained. Manufacturing method. 2. Impact resistance is obtained by continuously polymerizing a styrene monomer containing a rubber-like substance in the presence of a solvent, using an organic peroxide as a polymerization initiator, and in the presence of a chain transfer agent. (A) The amount of the solvent in the raw material mixture is 25% by weight or less, and the amount of the rubber-like substance is 3 to 12% by weight, (b) per 100 parts by weight of the raw material mixture. 0.001 to 0.20 parts by weight of organic peroxide is used, and at least a part thereof is added to the raw material mixture at the initiation of polymerization. (C) In the first step, the total amount of the organic peroxide per 100 parts by weight of the raw material mixture is 100% by weight. When the amount of decomposition (parts by weight) is X ₁ and the amount of addition of the chain transfer agent (parts by weight) is Y ₁ , it is added so that 1.0 ≦ X ₁ / Y ₁ ≦ 3.0. Perform bulk polymerization until 1.5 times the amount of polymer is produced. (D) In the second step, 10
Decomposition amount (parts by weight) of organic peroxide per 0 parts by weight is X ₂ ,
When the added amount (parts by weight) of the chain transfer agent is Y ₂ , 1.0 ≦ X ₂ / Y ₂ ≦ 4.5 is added, and the mixture is agitated until the polymerization addition rate of all monomers reaches 18-40%. Polymerization is continued to disperse the rubber-like substance into particles in the polymer, and (e) styrene having a rubber-like substance content of 3 to 20% by weight by bulk polymerization and / or suspension polymerization in the third step. A method for producing an impact-resistant styrene-based resin, which comprises polymerizing until a system-based polymer is obtained.