KR20020043764A - Continuous process for preparation of acrylonitrile-butadiene-styrene resins having superior impact strength - Google Patents

Abstract

The present invention relates to a continuous polymerization method of acrylonitrile-butadiene-styrene resin having excellent impact resistance, in particular rubber particles grafted by bulk or solution polymerization in two or more fully stirred tank reactors A method for continuously producing a rubber-modified styrene-acrylonitrile resin dispersed in a copolymer continuous phase of styrene.

The present invention for this purpose, in the method for producing an ABS resin excellent in impact resistance, a) i) aromatic vinyl monomer; Ii) vinyl cyanated monomers; Iii) a rubber polymer dissolved in the monomer mixture of iii) and ii) above; And iii) continuously supplying a liquid composition comprising a dilution solvent to the first fully stirred tank reactor and continuously polymerizing a grafting step to prepare a reaction mixture comprising a rubber graft copolymer and a glass copolymer; b) continuously feeding the reaction mixture of step a) to a second fully stirred tank reactor, and subjecting to continuous polymerization to increase the glass copolymer than the rubber graft copolymer to invert phase; c) continuously feeding the reaction mixture of step b) into at least one third liquid immersion reactor and continuously polymerizing to increase the conversion of unreacted monomers to the glass copolymer; And d) a post-treatment step of preparing an ABS resin by removing unreacted monomers and diluting solvents from the reactants of step c).

The method of preparing the ABS resin of the present invention enables the grafting of monomers to the rubber polymer evenly and in a large amount using a fully stirred tank reactor, and evenly dispersing the rubber particles and controlling the particle size by introducing an appropriate phase inversion reactor. This is possible to have an effect of providing a method for producing an ABS resin having excellent impact resistance and glossiness.

Description

CONTINUOUS PROCESS FOR PREPARATION OF ACRYLONITRILE-BUTADIENE-STYRENE RESINS HAVING SUPERIOR IMPACT STRENGTH}

[Industrial use]

The present invention relates to a continuous polymerization method of acrylonitrile-butadiene-styrene-based resin (hereinafter referred to as 'ABS resin') having excellent impact resistance, and in particular, two or more liquid-type stirred baths The present invention relates to a method for continuously producing a rubber-modified styrene-acrylonitrile resin in which rubber particles grafted by a bulk or solution polymerization reaction in a reactor are dispersed in a copolymer continuous phase of an aromatic vinyl monomer and a vinyl cyanide monomer.

[Private Technology]

A number of techniques for producing ABS resins by bulk or solution polymerization are known. For example, U.S. Patent No. 3,243,481 describes ABS resins using two vertical tower reactors in series in one continuous stirred tank reactor, the first reactor having a conversion rate of 10 wt. After polymerization in%, the temperature was increased in the remaining reactors to obtain a conversion of 90% by weight.

In addition, US Pat. No. 4,239,863 discloses a method for producing ABS resin using a mass or mass-suspension polymerization process. In the first reactor, a low decomposition temperature t-butyl peroxy initiator was used to react at a conversion rate of about 10% by weight while the reactant maintained a plug flow, and then 40% by weight through stirring in the next reactor. A degree of conversion is obtained and the polymerization is terminated at a conversion rate of about 60% by weight in the remaining reactors.

U. S. Patent No. 3,931, 356 also discloses a process for producing ABS resins by blending grafted diene rubbers prepared by emulsion polymerization to styrene-acrylonitrile copolymers prepared using a mass polymerization process. In the mass polymerization process, by using a stirred tank reactor having a constant liquid level, temperature control and uniform mixing are easy, and high conversion can be obtained.

EP 632,072A2 and U.S. Patent 5,506,304 describe a process for continuously producing rubber modified styrene resins from rubber, styrene monomers, and acrylonitrile monomers by continuous scalpel or solution polymerization. This method uses two or more successive polymerization apparatuses, in which the polymerization of the monomers is carried out so that the rubber phase does not become a dispersed phase in the first step, and then the polymerization of the monomers is continued in the second step so that the rubber phase becomes a dispersed phase. Configure. The second and subsequent reactors are also fed monomers for polymerization. ABS resin produced in this way is improved impact resistance and surface gloss.

However, the methods listed above are not easy to control the size and dispersion of rubber particles, which are important in making the reaction process complicated, the operating conditions are difficult, and the desired impact resistance and surface glossiness. Therefore, the development of a method for producing a resin having excellent impact resistance and the like in a simpler process and operating conditions is required.

In consideration of the problems of the prior art, the grafting of monomers in the rubber polymer is made evenly and in a large amount, even in a simple reaction step, and the uniform dispersion of rubber particles and control of the particle size are achieved by introducing an appropriate phase inversion reactor. It is an object of the present invention to provide a method capable of producing an ABS resin having excellent impact resistance and glossiness.

[Means for solving the problem]

In order to achieve the above object, the present invention provides a method for producing an ABS resin excellent in impact resistance,

a) an aromatic vinyl monomer;

Ii) vinyl cyanated monomers;

Iii) a rubber polymer dissolved in the monomer mixture of iii) and ii) above; And

Iii) diluent solvent

Continuously supplying a liquid composition comprising a first fully liquid stirred tank reactor

High, continuous polymerization to include rubber graft copolymers, and glass copolymers

A grafting step of preparing a reaction mixture;

b) continuously supplying the reaction mixture of step a) to a second fully stirred tank reactor

And unpolymerized monomers were continuously polymerized to give the glass copolymer a rubber graft ball.

Phase inversion over polymer;

c) the reaction mixture of step b) is one or more third fully liquid stirred tank reactor

To the glass copolymer and continuously polymerized

Increasing the conversion rate of; And

d) ABS by removing the unreacted monomer and dilution solvent in the reactant of step c)

Post-Processing Step to Prepare Resin

It provides a method comprising a.

Hereinafter, the present invention will be described in detail.

[Action]

The present invention relates to a process using four successive fully liquid stirred tank reactor systems in the production of ABS resins from aromatic vinyl monomers, vinyl cyanide monomers, and rubber polymers using block or solution polymerization.

Specifically, the present invention consists of a) a grafting step, b) a phase inversion step, c) a conversion rate increase reaction step, and d) a post-treatment step.

When explaining the present invention step by step as follows.

In the first step, a) the grafting step, a liquid composition comprising (i) an aromatic vinylic monomer, ii) a vinyl cyanide monomer, iv) a rubber polymer dissolved in the monomer mixture of iii) and ii), and iii) a diluting solvent. Was continuously fed into a fully liquid stirred tank reactor to continuously polymerize to produce a rubber graft copolymer in which monomers were grafted into copolymers on the rubber particles, and at the same time, the rubber was not grafted on the rubber under the condition of being dispersed in the continuous phase of the rubber. Copolymers of the above monomers (hereinafter referred to as 'free copolymers') are also polymerized.

The reaction conditions in this step are adjusted to be considerably predominant than when the rubber graft copolymer forms an grafted glass copolymer. In order to achieve this object, the reaction temperature is maintained at about 80 to 125 ° C., more preferably at about 90 to 110 ° C., the stirring speed is 50 to 150 rpm, and the residence time is maintained at 1 to 4 hours. If this condition is satisfied, the conversion rate in the first step is kept within 10% by weight. Under the reactor conditions, the grafted rubber phase becomes a continuous phase, which occupies a large volume in the entire reaction system, and the glass copolymer phase becomes a dispersed phase in a relatively small amount. Therefore, no phase inversion occurs in the first stage.

(Iii) The aromatic vinyl monomer is at least one selected from the group consisting of styrene, α-methyl styrene, para-methyl styrene, vinyl toluene, t-butyl styrene, and chlorostyrene. Among the aromatic vinyl monomers listed above, styrene is particularly preferred. The aromatic vinyl monomer uses 50 to 80% by weight based on the total weight of the mixture used in step a).

The vinyl cyanide monomer of ii) is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, and ethacrylonitrile. Of the vinyl cyanated monomers listed above, acrylonitrile is particularly preferred. The vinyl cyanated monomer uses 5 to 45 wt% based on the total weight of the mixture used in step a).

As the rubber polymer of iii), an uncrosslinked linear butadiene polymer which can be dissolved in the monomer mixture, such as butadiene rubber or styrene-butadiene copolymer, is used. More preferably, the solution viscosity is 10 to 40 cps (centipoise), the cis content is 30% by weight or more, and the vinyl group content is 10 to 25% by weight in a styrene solvent to lower the viscosity of the reaction solution and to facilitate the dispersion of rubber particles. Phosphorus styrene-butadiene copolymer rubber is used. The content of diene rubber polymer used is 5-20% by weight of the total weight of the raw material mixture, more preferably 8-15% by weight.

The diluent of iii) performs the function of controlling the viscosity and controlling the molecular weight at high conversion rate. Specifically, ethylbenzene, toluene, ethylxylene, or benzene may be used in the raw material mixture, and based on the total weight of the raw material mixture, 5 to 25 It contains by weight.

The conversion rate is obtained according to the following equation.

[Equation 1]

The polymerization of step a) begins with an initiation reaction using heat or an initiator. As an initiator, a conventional organic peroxide initiator such as peroxyketal, dialkylperoxide, diacylperoxide, or peroxyester can be used. . When using an initiator, from 0.005 to 0.5% by weight, based on the total weight of the raw material mixture, is used.

The second step is b) a phase inversion reaction, in which the amount of glass copolymer polymerized in the second reactor increases, causing a phase inversion of the grafted rubber in the form of particles dispersed in the continuous phase of the glass copolymer. .

More specifically, the amount of glass copolymer is gradually increased under the reaction conditions in which the unreacted raw material mixture and reactant are continuously supplied to the second fully liquid stirred tank reactor in the first reactor so that the glass copolymer is polymerized. After a certain point, the glass phase becomes larger than the rubber phase, and the rubber phase undergoes a phase inversion in which the rubber phase is dispersed on the glass copolymer. For example, when styrene is used as the aromatic vinyl monomer and acrylonitrile is used as the vinyl cyanide monomer, the rubber particles are filled with styrene-acrylonitrile (hereinafter referred to as SAN) in the inner space of the rubber. It is a structure in which rubber surrounds the outside, and these single structures are often meshed in a single rubber particle. The reaction conditions of the second stage in which this phase inversion can take place are from 120 to 140 ° C., with a residence time of from 1 to 3 hours so that the conversion is from 10 to 50% by weight. The stirring speed is about 80 to 200 rpm in order for the rubber particles to be sufficiently dispersed.

The third step is to increase the conversion rate by c) increasing the conversion rate by continuously polymerizing the glass copolymer in the reactor.

Specifically, the reaction conditions are adjusted to further increase the reaction of the glass copolymer, for example free SAN, and to have a sufficiently high molecular weight using one or more fully stirred tank reactors. In this step, in order to adjust the temperature conditions of the reactor at 130 to 150 ℃, the conversion rate is 50 to 80% by weight, the residence time in the reactor is suitable for 2 to 6 hours, the stirring speed is 20 to 80 rpm Adjust

The fourth step is d) a post-treatment step to remove the unreacted monomer from the volatilization of the final polymer solution prepared through the previous steps to prepare an ABS resin having excellent impact resistance.

Specifically, the post-treatment step is carried out in the solid polymer polymer with the reaction monomer and diluent supplied in the third step and the resulting polymer polymer at a low pressure of 200 to 250 ° C. and a pressure of 30 Torr or less. It is a volatilization process to remove. After the granulation process after the volatilization process, the final ABS resin can be obtained.

The advantage of the present invention is that the degree of grafting on the rubber through the fully liquid stirred tank reactor can be obtained in an optimal state, that is, grafting on the rubber is made even and grafting as much as possible. The size of the particles can be adjusted to enable even dispersion of the rubber particles and to achieve good impact resistance and glossiness. This effect can be achieved by adjusting the operating conditions of the reaction step as described above even if the same rubber is used.

The present invention will be described in more detail with reference to the following examples and comparative examples. However, an Example is for illustrating this invention and is not limited only to these.

EXAMPLE

Example 1

(Grafting step)

8.0 parts by weight of styrene-butadiene rubber, 57.6 parts by weight of styrene, 14.4 parts by weight of acrylonitrile, and 20.0 parts by weight of ethylbenzene were added to a 200-l container having a stirrer to dissolve the styrene-butadiene rubber, and 200 liters of storage with a stirrer. The liquid composition was stored in a container.

The styrene-butadiene rubber used was a styrene-butadiene linear diblock copolymer having a styrene content of 15% by weight and a butadiene content of 85% by weight. The rubber solution viscosity was 10 cps in a styrene solution having a rubber concentration of 5% by weight at 25 ° C. .

The liquid composition was supplied to a 26 L liquid-type stirred tank reactor having a stirrer and an outer wall cooling device at a flow rate of 12 L / h through a 30 L raw material mixing vessel immediately before the reactor was charged, and the graft reaction was carried out at the time of opening. At this time, the reaction temperature was 110 ℃, the stirring speed was 100 rpm, the residence time was 2.2 hours, using a gravity-feed gear pump to maintain a constant feed amount.

(Phase switch phase)

The reactants and unreacted materials passed through the grafting step were continuously supplied to a 16 L fully stirred tank reactor having a stirrer and an outer wall cooling means to carry out a polymerization reaction. At this time, the reaction temperature was 120 ℃, the stirring speed was 150 rpm, the residence time was 1.3 hours.

(Increase your conversion rate)

The reactants and unreacted materials passed through the phase inversion step were continuously supplied in two successive 16 L fully liquid stirred tank reactors having a stirrer and outer wall cooling means to carry out the polymerization reaction. At this time, the first was 130 ℃ and the second reactor was maintained at 140 ℃, the stirring speed was 50 rpm, the residence time was 1.3 hours.

(Post-processing step)

The final polymer solution prepared through the previous steps was introduced into a generally used volatilizer to sufficiently remove unreacted monomers, etc., and then a final ABS resin was obtained through granulation. At this time, the temperature of the volatilization tank was 230 degreeC, and the pressure was maintained at 30 Torr.

The total residence time during these four steps was about 6.1 hours. A total of four reactors were run during the first three stages, with conversions at the reactor outlet after each reactor being 8%, 25%, 45%, and 60% by weight, respectively.

In addition, the average particle size of the rubber after completion of the reaction was measured through an electron micrograph (indicated here by Transmission Electron Microscopes (TEM)), and the Izod impact strength was 1/4 ″ at 23 ° C. using the ASTM D256 test method. The results of the measurement were shown in Table 1 below.

At this time, the size distribution of the rubber particle diameter did not show a large deviation, and the distribution of particles was generally spread evenly on the glass SAN continuous.

Example 2

The same procedure as in Example 1 was carried out in 4 steps, but in the grafting step, 0.01 part by weight of 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, which was a peroxide initiator, was added. And the temperature of the reactor was set at 100 ° C.

Subsequent phase inversion steps, increasing conversion rates, and post-treatment steps were carried out in the same manner as in Example 1.

Conversion rates at the reactor outlet after passing through each reactor were 10% by weight, 35% by weight, 50% by weight and 65% by weight, respectively.

In addition, the average particle size and the Izod impact strength of the rubber after the completion of the reaction was measured in the same manner as in Example 1 and the results are shown in Table 1 below.

Example 3

The procedure of Example 4 was carried out in the same manner as in Example 1, but in the (grafting step), 0.02 weight of 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane as a peroxide initiator was Part was added and the temperature conditions of the reactor were set at 100 ° C.

Subsequent phase inversion steps, increasing conversion rates, and post-treatment steps were carried out in the same manner as in Example 1.

Conversion rates at the reactor outlet after passing through each reactor were 10% by weight, 40% by weight, 55% by weight and 70% by weight, respectively.

In addition, the average particle size and the Izod impact strength of the rubber after the completion of the reaction was measured in the same manner as in Example 1 and the results are shown in Table 1 below.

TABLE 1

division Example 1 Example 2 Example 3 Type and amount of initiator (parts by weight) Thermal initiation 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, 0.01 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, 0.02 Maximum particle size of rubber particles (nm) 700 500 400 Dispersion of rubber particles pus pus pus Izod impact strength (kgcm / cm) 12.4 14.3 15.8

The method of preparing the ABS resin of the present invention enables the grafting of monomers to the rubber polymer evenly and in a large amount using a fully stirred tank reactor, and evenly dispersing the rubber particles and controlling the particle size by introducing an appropriate phase inversion reactor. This enables the production of ABS resin having excellent impact resistance and glossiness.

Claims (14)

a) an aromatic vinyl monomer; Ii) vinyl cyanated monomers; Iii) a rubber polymer dissolved in the monomer mixture of iii) and ii) above; And Iii) diluent solvent Continuously supplying a liquid composition comprising a first fully liquid stirred tank reactor High, continuous polymerization to include rubber graft copolymers, and glass copolymers A grafting step of preparing a reaction mixture; b) continuously supplying the reaction mixture of step a) to a second fully stirred tank reactor And unpolymerized monomers were continuously polymerized to give the glass copolymer a rubber graft ball. Phase inversion over polymer; c) the reaction mixture of step b) is one or more third fully liquid stirred tank reactor To the glass copolymer and continuously polymerized Increasing the conversion rate of; And d) ABS by removing the unreacted monomer and dilution solvent in the reactant of step c) Post-Processing Step to Prepare Resin Method for producing an ABS resin having excellent impact resistance comprising a. The method of claim 1, The liquid composition of step a) V) 50 to 80 wt% of an aromatic vinyl monomer; Ii) 5 to 45 wt% vinyl cyanated monomer; Iii) rubber polymers 5 to 20 dissolved in the monomer mixture of iii) and ii) above; weight%; And V) 5 to 25% by weight of diluent solvent Method for producing an ABS resin having excellent impact resistance comprising a. The method of claim 1, The method of manufacturing an ABS resin having excellent impact resistance, wherein the liquid composition of step a) further comprises 0.005 to 0.5 wt% of an initiator. The method of claim 3, wherein A method for producing an ABS resin having excellent impact resistance, wherein the initiator of (i) is peroxyketal, dialkylperoxide, diacylperoxide, or peroxyester. The method of claim 1, ABS resin having excellent impact resistance, wherein the aromatic vinyl monomer of step a) is selected from the group consisting of styrene, α-methyl styrene, para-methyl styrene, vinyl toluene, t-butyl styrene, and chlorostyrene. Method of preparation. The method of claim 1, The method of producing an ABS resin having excellent impact resistance, wherein the vinyl cyanated monomer of step a) is selected from the group consisting of acrylonitrile, methacrylonitrile, and ethacrylonitrile. The method of claim 1, The method of producing an ABS resin having excellent impact resistance, wherein the rubber polymer of step a) is a butadiene rubber or a styrene-butadiene copolymer. The method of claim 7, wherein The styrene-butadiene copolymer has a solution viscosity of 5 to 20 cps (centipoise) in a styrene solvent, a cis content of 30% by weight or more, and a styrene of 10 to 20% by weight. The method of claim 1, The method of producing an ABS resin having excellent impact resistance, wherein the dilution solvent of a) step iii) is ethylbenzene, toluene, ethyl xylene, or benzene. The method of claim 1, The grafting of step a) is a method of producing an ABS resin having excellent impact resistance at a reaction temperature of 80 to 125 ℃, a stirring speed of 50 to 150 rpm, and a residence time of 1 to 4 hours. The method of claim 10, A method for producing an ABS resin having excellent impact resistance, wherein the reaction temperature is 90 to 110 ° C. The method of claim 1, The phase inversion of step b) is a method of producing an excellent impact resistance ABS resin is carried out at a reaction temperature of 120 to 140 ℃, stirring speed of 80 to 200 rpm, and a residence time of 1 to 3 hours. The method of claim 1, The polymerization reaction of step c) is a method of producing an ABS resin having excellent impact resistance carried out under the conditions of reaction temperature 130 to 150 ℃, stirring speed 20 to 80 rpm, and residence time 2 to 6 hours. The method of claim 1, The post-treatment step of step d) is a method of producing an excellent impact resistance ABS resin is carried out by volatilizing the unreacted monomer and dilution solvent in the solid polymer at a reaction temperature of 200 to 250 ℃, pressure 30 Torr or less.