KR100587650B1 - Continous Polymerization Process of Rubber-Modified Styrenic Resin with Good Falling Dart Impact - Google Patents

Abstract

The continuous production method of the rubber-modified styrene-based resin having excellent practical impact strength of the present invention comprises (1) a liquid feed material composition obtained by dissolving three different synthetic butadiene polymers in a styrene-based monomer at 90-130 ° C. in a first reactor. The phase change reaction was carried out for a period of ˜2 hours to produce a first polymer having a conversion rate of 5 to 15% of the monomer, and (2) the first polymer was continuously added to the second reactor for 1 to 2 hours at 110 to 145 ° C. Polymerization to produce a second polymer having a monomer conversion of 15 to 30%. (3) The second polymer was continuously added to a third reactor and reacted at 140 to 160 ° C. for 0.5 to 1.5 hours. A third polymer having 30 to 60% was produced, and (4) the third polymer was continuously added to the fourth reactor and reacted at a range of 150 to 180 ° C. to produce a fourth polymer having a monomer conversion of 60 to 90%. Let's do that (5) a step of removing the unreacted monomer and solvent by introducing a fourth polymer in the volatile content eliminator.

Styrene butadiene block copolymer, cis polybutadiene, trimodal

Description

Continous Polymerization Process of Rubber-Modified Styrenic Resin with Good Falling Dart Impact}             

1 is a process diagram schematically showing a continuous polymerization apparatus for producing a rubber-modified styrene resin having excellent practical impact strength according to the present invention.

Field of invention

The present invention relates to a continuous production method of rubber modified styrene resin. More specifically, the present invention is to graft the final product by introducing a suitable reactor before and after the phase transition of the liquid feed material composition in which the three different synthetic butadiene polymers in a specific ratio in the styrene monomer are introduced. The present invention relates to a method of continuously producing a rubber-modified styrene resin having high efficiency, having a rubber particle size distribution having a trimodal form, having an excellent practical impact strength, and having an excellent Izod impact strength.

Background of the Invention

Styrene-based resins have been produced commercially a lot of excellent transparency, thermal stability, processability. In particular, rubber modified polystyrene resins having enhanced impact resistance have been developed by introducing rubber particles into styrene resins. Such rubber-modified styrene resins disperse rubber, particularly polybutadiene particles, having low glass transition temperature (Tg) in monovinylidene aromatic compounds such as styrene, alpha-methyl styrene and ring-substituted styrene in a matrix of styrene polymers. The impact resistance is strengthened.

In particular, as consumer preferences for large products have increased in recent years, home appliance companies have increased the output of large products, and at the same time, there are attempts to reduce the thickness of products to reduce the weight and manufacturing cost of large products. However, if the thickness of the product is reduced, the practical impact strength is lowered, so there is a problem that a crack occurs in the appearance of the molded article even with a small impact. Therefore, the resin manufacturer is focusing on research and development of products with excellent practical impact strength to compensate for these disadvantages.

Therefore, in order to compensate for the disadvantage of low practical impact strength, a method of improving the practical impact strength by adding polydimethylsiloxane to the styrene resin to increase the flexibility of the resin, such as Japanese Patent Application Laid-Open No. 60-217254, has been tried. I have a problem.

Another conventional technique for increasing the practical impact strength is rubber modified styrene having different rubber particle diameters by dispersing the particle size of the rubber phase, which is a dispersed phase of the rubber modified styrene resin, in a bimodal or trimodal form. There is a method of pre-polymerizing the system and then mixing in a reactor after the phase transition. However, in order to make different particle diameters, not only reactors having different polymerization raw material costs are required in the previous phase transition, but also have disadvantages of complicated control for polymerization and insufficient practical impact strength, and satisfactory surface gloss. There is a disadvantage that it is difficult to obtain a product having a degree.

Another conventional technique for increasing the practical impact strength is a method of increasing the binding force of the rubber phase in the dispersed phase and the polystyrene phase in the continuous phase by improving the graft ratio. However, the method of increasing the graft ratio of the rubber phase and the polystyrene phase by using the initiator has a problem that the continuous bulk polymerization is difficult due to the increase of the reactivity with the use of the initiator, and the appearance of the product is deteriorated.

In order to overcome the above problems, the present inventors use a synthetic butadiene polymer having three different properties in a specific ratio, and the liquid feed material composition dissolved in the styrene-based monomer in the form of a full charge in the reaction before the phase transition. Grafting efficiency of the final product is high by using the full-charge reactor, the CSTR reactor in the phase transition stage, and the horizontal reactor and the flow-flow full charge reactor in the post phase transition phase. The particle size distribution has a tree modal shape, leading to the development of a continuous production method of rubber-modified styrene resin having excellent practical impact strength and excellent Izod impact strength.

An object of the present invention is to provide a continuous production method of a rubber-modified styrene resin having a high graft efficiency and a particle size distribution of a rubber phase in a dispersed phase having a trimodal form.

Another object of the present invention is to provide a continuous process for producing a rubber-modified styrene resin having a narrow molecular weight distribution and excellent practical impact strength.

Still another object of the present invention is to provide a continuous process for producing a rubber-modified styrene resin having a narrow molecular weight distribution and having an excellent Izod impact strength.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the content of the present invention will be described in detail.

The continuous production method of the rubber-modified styrene-based resin having excellent practical impact strength of the present invention comprises (1) a liquid feed material composition obtained by dissolving three different synthetic butadiene polymers in a styrene-based monomer at 90-130 ° C. in a first reactor. The phase change reaction was carried out for a period of ˜2 hours to produce a first polymer having a conversion rate of 5 to 15% of the monomer, and (2) the first polymer was continuously added to the second reactor for 1 to 2 hours at 110 to 145 ° C. To produce a second polymer having a monomer conversion of 15 to 30%. (3) The second polymer was continuously added to a third reactor and reacted at 140 to 160 ° C. for 0.5 to 1.5 hours. This 30-60% of the third polymer was produced, and (4) the third polymer was continuously introduced into the fourth reactor and reacted in the range of 150 to 180 DEG C to produce a fourth polymer having a monomer conversion of 60 to 90%. Create, draw And (5) removing the unreacted monomer and solvent by adding the fourth polymer to a volatile remover. Detailed description of each of these steps is as follows.

Preparation of First Polymer

The method for producing a rubber-modified styrene resin having excellent practical impact strength according to the present invention first dissolves a styrene monomer and three rubbers having different characteristics in a dissolution tank, and then transfers the rubber to a full charge reactor, which is a first reactor. The ratio of the styrene-based monomer and the rubber solution is added in a usual ratio, which can be easily carried out by those skilled in the art.

The styrene monomers include styrene, α-methyl styrene, α-ethyl styrene, p-methyl styrene, and the like. Monomers other than styrene may be mixed with unsaturated nitrile monomers and / or alkyl acrylate monomers, and specific examples thereof include alkyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, acrylonitrile and the like.

The rubber used in the present invention is a mixture of three types of rubbers such as Styrene-Rubber Copolymer, Low Cis Polybutadiene Rubber, and High Cis Polybutadiene Rubber. do.

The styrene butadiene copolymer has a polystyrene content of 35-45% and a viscosity of 30-40 centipoise of a rubber solution dissolved in a styrene monomer to prepare a 5% by weight solution.

The low seed polybutadiene rubber has a 1,4-cis content of 30-40% and a viscosity of 150-200 centipoise of a rubber solution dissolved in a styrene monomer to prepare a 5% by weight solution.

The high seed polybutadiene rubber has a 1,4-cis content of 95% or more and a viscosity of 140-170 centipoise of a rubber solution prepared by dissolving in a styrene monomer as a 5% by weight solution.

In the present invention, 15-30 parts by weight of the styrene butadiene block copolymer, 40-65 parts by weight of low sheath polybutadiene rubber, and 15-35 parts by weight of high sheath polybutadiene rubber are used.

In addition, as a solvent according to the present invention, aromatic compounds such as ethyl benzene (Ethyl Benzene), benzene, toluene, and methyl ethyl ketone may be used.

In the first polymerization reactor, additives such as an initiator and a molecular weight regulator are used, and tertiary butyl peroxyacetate, tertiary butyl peroxybenzoate, and the like are used as the initiator. As the molecular weight modifier, α-methyl styrene dimer, mercaptan, halide, terpene and the like are used.

The first reactor of the present invention is a full charge type in which the polymerization mixture is fed to the bottom of the reactor (CSTR) in a continuous flow stirred reactor and the reactant is discharged upwards to the reactor. The polymerization temperature is carried out for 1-2 hours at 90-130 ℃. At this time, the conversion rate is 5-15% and the reaction is transferred to the second polymerization reactor after the phase change reaction.

The product of the first polymerization reactor is in the form of a polystyrene polymerized in a continuous rubber phase.

Preparation of Second Polymer

The first polymer is continuously introduced into a second reactor, which is a phase transfer reactor, to prepare a second polymer having a monomer conversion of 15-30%.

The second reactor of the present invention is a continuous flow stirred reactor as a phase transfer reactor.

The polymerization temperature in the second reactor is 110-145 ° C., and the polymerization proceeds for 1-2 hours with a conversion of 15% -30%.

An important role of the second polymerization reactor of the present invention is a phase transfer reactor in which rubber particles are dispersed on continuous polystyrene. The reactants of the first polymerization reactor are dispersed in a polystyrene phase on the continuous rubber, but the volume volume of the polystyrene produced by the polymerization of the second polymerization reactor and the volume of the initially charged rubber (including polystyrene grafted to rubber) become equal. At this point, the phase transition begins and a rubber dispersed phase is formed on the polystyrene continuous phase.

The particle diameter and distribution of the rubber particles produced through the phase transition process and the occlusion of polystyrene in the rubber particles are important factors for determining the physical properties of the rubber-modified styrene resin.

Preparation of Third Polymer

The second polymer is continuously introduced into a third reactor to prepare a third polymer having a monomer conversion of 30 to 60%.

The third reactor is a flow flow of reactants using a horizontal reactor, and reacts at 0.5-1.5 hours at a reaction temperature of 140-160 ° C., with a conversion rate of 30-60%.

Preparation of Fourth Polymer

The third polymer is continuously added to the fourth reactor to prepare a fourth polymer having a monomer conversion of 60 to 90%.

The fourth reactor is a final reactor of the polymerization stage and polymerizes at 60-90% conversion at a temperature of 150-180 ° C.

The fourth reactor of the present invention is divided into four zones from the inlet to the outlet, and is a full-charged flow flow reactor capable of temperature control and easy control of reaction heat generated by polymerization. The polymer having a conversion rate of 60-90% through the fourth reactor is transferred to a devolatilizer to remove unreacted monomers and solvents, thereby preparing a final rubber-modified styrene resin.

The invention can be better understood by the following examples, which are intended to illustrate the invention and are not intended to limit the scope of protection defined by the appended claims.

Example 1

87.0 parts by weight of styrene monomer, 8.0 parts by weight of polybutadiene rubber (20% by weight of styrene butadiene copolymer rubber, 50% by weight of low-seas polybutadiene rubber, and 30% by weight of high-seas polybutadiene rubber) and 5.0 parts by weight of ethyl benzene in a complete mixing tank After dissolving, a reaction raw material solution was prepared and fed to a full-charge continuous flow stirred reactor (Full-Charge CSTR) which is a first reactor. The reaction was carried out at 120 ° C. and 110 RPM for 1 hour in the first reactor. The reactant passed through the first reactor was reacted for 1.5 hours in a continuous flow stirred reactor, the second reactor at 135 ° C. and 35 RPM, and then introduced into a horizontal reactor, the third reactor. After reacting for 0.7 hours at 155 ° C. and 21 RPM in the third reactor, the third reactor was transferred to a floc flow-type full charge reactor. In the fourth reactor, the reaction was carried out by increasing the temperature step by step, and the reaction temperature was reacted at 160 ° C, 162 ° C, 164 ° C, and 166 ° C. The polymers passed through the four reactors were removed by pellets after removal of unreacted monomers and solvents through a volatilization tank, thereby preparing a final polymer.

Example 2

The same procedure as in Example 1 was carried out except that 25 wt% of styrene butadiene copolymer rubber, 45 wt% of low seas polybutadiene rubber, and 30 wt% of high seas polybutadiene rubber were changed.

Example 3

The same procedure as in Example 1 was performed except that 20 wt% of styrene butadiene copolymer rubber, 60 wt% of low seas polybutadiene rubber, and 20 wt% of high seas polybutadiene rubber were used.

Each polymerization condition of Example 1-3 is shown in Table 1.

division Example 1 Example 2 Example 3 Input Styrene Monomer Content 87 parts by weight Input polybutadiene rubber content 8 parts by weight Input ethyl benzene content 5 parts by weight Rubber type and composition ratio Styrene Butadiene Copolymer Rubber 20 wt% 25% by weight 20 wt% Low Seas Poly Butadiene Rubber 50 wt% 45 wt% 60% by weight High Seas Poly Butadiene Rubber 30 wt% 30 wt% 20 wt% First reactor Temperature 120 ℃ RPM 110 Residence time 1.0 hours Second reactor Temperature 135 ℃ RPM 35 Residence time 1.5 hours Third reactor Temperature 155 ℃ RPM 21 Residence time 0.7 hours Fourth reactor Temperature (1 zone / 2 zones / 3 zone / 4 zones) 160 ℃ / 162 ℃ / 164 ℃ / 166 ℃ Residence time 0.6 hours

Comparative Example 1

The same procedure as in Example 1 was performed except that 0 wt% of styrene butadiene copolymer rubber, 50 wt% of low seas polybutadiene rubber, and 50 wt% of high seas polybutadiene rubber were changed.

Comparative Example 2

The same procedure as in Example 1 was performed except that 50 wt% of styrene butadiene copolymer rubber, 0 wt% of low seas polybutadiene rubber, and 50 wt% of high seas polybutadiene rubber were changed.

Comparative Example 3

The same procedure as in Example 1 was performed except that 50 wt% of styrene butadiene copolymer rubber, 50 wt% of low seas polybutadiene rubber, and 0 wt% of high seas polybutadiene rubber were changed.

Comparative Example 4

The same procedure as in Example 1 was conducted except that 100 wt% of styrene butadiene copolymer rubber, 0 wt% of low seas polybutadiene rubber, and 0 wt% of high seas polybutadiene rubber were changed.

Comparative Example 5

The same procedure as in Example 1 was performed except that 0 wt% of styrene butadiene copolymer rubber, 100 wt% of low seas polybutadiene rubber, and 0 wt% of high seas polybutadiene rubber were changed.

Each polymerization condition of Comparative Example 1-5 is shown in Table 2.

division Comparative Example One 2 3 4 5 Input Styrene Monomer Content 87 parts by weight Input polybutadiene content 8 parts by weight Input ethyl benzene content 5 parts by weight Rubber type and composition ratio Styrene Butadiene Copolymer Rubber 0% by weight 50 wt% 50 wt% 100 wt% 0% by weight Low Seas Poly Butadiene Rubber 50 wt% 0% by weight 50 wt% 0% by weight 100 wt% High Seas Poly Butadiene Rubber 50 wt% 50 wt% 0% by weight 0% by weight 0% by weight First reactor Temperature 120 ℃ RPM 110 Residence time 1.0 hours Second reactor Temperature 135 ℃ RPM 35 Residence time 1.5 hours Third reactor Temperature 155 ℃ RPM 21 Residence time 0.7 hours Fourth reactor Temperature (1 zone / 2 zones / 3 zones / 4 zones) 160 ℃ / 162 ℃ / 164 ℃ / 166 ℃ Residence time 0.6 hours

Physical property analysis of the final polymer prepared in Examples 1-3 and Comparative Example 1-5 was performed and the results are shown in Table 3. The physical property evaluation method is as follows.

(1) Izod impact strength (kgcm / cm): Measured by ASTM D-256.

(2) Flowability (g / 10 min, 5 kg, 200 ° C.): measured by ASTM D-1238.

(3) Measurement of rubber particle size and distribution of final product: It was measured using Malvern's Mastersizer S Ver 2.14.

(4) Practical impact strength: measured by ASTM D-3029.

Example Comparative Example One 2 3 One 2 3 4 5 First reactor Monomer conversion 5.8 5.5 5.7 5.5 5.7 5.4 5.8 5.5 Second reactor Monomer conversion 28.5 28.0 28.3 28.9 28.1 28.3 28.5 28.7 Third reactor Monomer conversion 51.5 52.0 51.8 51.9 52.1 52.3 52.0 52.1 Fourth reactor Monomer conversion 72.0 72.3 72.1 72.3 71.9 71.8 72.0 72.3 Impact strength 21.2 20.1 22.5 15.5 16.2 14.0 7.0 12.2 liquidity 2.9 3.0 3.1 2.9 2.8 3.0 2.9 2.8 Rubber Particle Size (%) 0.2-0.6㎛ 15% 17% 16% 2% 42% 38% 95% 0% 1.2-2.2㎛ 65% 60% 69% 38% 3% 57% 5% 7% 3.0-4.5㎛ 20% 23% 15% 60% 55% 5% 0% 93% Practical Impact Strength (J) 26 25 27 14 16 15 5 10

As shown in Table 3, when three different types of rubber are used in an appropriate ratio, the rubber particle size has a trimodal form, and thus the impact strength is remarkably excellent, and the Izod impact strength is also excellent. Able to know.

The present invention uses a synthetic butadiene polymer having three different properties in a specific ratio, and a full-charge reactor, phase transition, in which a liquid feed material composition dissolved in a styrene-based monomer is used in a reaction before a phase change. By applying optimal reaction conditions using the CSTR reactor in the stage and the horizontal reactor and the flow-flow full charge reactor in the later phase transition, the rubber particle size distribution of the final product forms a trimodal shape, thus providing a practical impact strength. It has the effect of the invention which provides the continuous manufacturing method of the rubber-modified styrene resin which is excellent and also the Izod impact strength is excellent.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (7)

(1) A liquid feed material composition in which three different synthetic butadiene polymers were dissolved in a styrene monomer was reacted in a first reactor at 90 to 130 ° C. for 1 to 2 hours to a point before the phase change, and the monomer conversion rate was 5 to 15%. Producing a first polymer; (2) continuously introducing the first polymer into a second reactor to polymerize at 110 to 145 ° C. for 1 to 2 hours to produce a second polymer having a monomer conversion of 15 to 30%; (3) continuously adding the second polymer to the third reactor and reacting at 140 to 160 ° C. for 0.5 to 1.5 hours to produce a third polymer having a monomer conversion of 30 to 60%; (4) continuously adding the third polymer to the fourth reactor and reacting in the range of 150 to 180 ° C. to produce a fourth polymer having a monomer conversion of 60 to 90%; And (5) adding the fourth polymer to a volatile remover to remove unreacted monomers and solvents; Step 3, wherein the three synthetic butadiene polymer is a mixture of 15-30 parts by weight of styrene butadiene block copolymer, 40-65% by weight of low sheath polybutadiene rubber, and 15-35% by weight of high sheath polybutadiene rubber A continuous production method of a rubber-modified styrene resin having excellent practical impact strength. The method of claim 1, wherein the styrene monomer is a styrene monomer alone or a mixture with an unsaturated nitrile monomer and / or an alkyl acrylate monomer. delete The styrene butadiene block copolymer has a styrene content of 35-45% by weight, and the viscosity of the rubber solution prepared in a 5% by weight solution dissolved in styrene monomer is 30-40 centipoise. A continuous production method of a rubber-modified styrene resin having excellent practical impact strength. The rubber solution of claim 3, wherein the low seed polybutadiene rubber has a 1,4-cis content of 30-40%, and the viscosity of the rubber solution prepared by dissolving the low seed polybutadiene rubber in a styrene monomer is 5% by weight. A method for continuously manufacturing a rubber-modified styrene resin having excellent practical impact strength, characterized in that it is 200 centipoise. The rubber solution of claim 3, wherein the high seed polybutadiene rubber has a 1,4-cis content of 95% or more, and the viscosity of the rubber solution prepared by dissolving the high seed polybutadiene rubber in a styrene monomer to a 5% by weight solution is 140-170. A continuous production method of a rubber-modified styrene resin having excellent practical impact strength, characterized in that it is centipoise. The reactor according to claim 1, wherein the first reactor is a full charge continuous stirred tank reactor; The second reactor is a continuous stirred tank type reactor as a phase transfer reactor; The third reactor is a horizontal reactor for producing a flux flow type of reactant; And the fourth reactor is divided into four areas from the inlet to the outlet, each of which is a flow-flow full charge reactor characterized in that the temperature control is possible, and the control of the reaction heat generated by polymerization is easy. Excellent process for producing rubber-modified styrene resins.

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