KR20050015877A - Continuous Process for Preparing High Impact Polystyrene Resin - Google Patents

Abstract

PURPOSE: Provided is a continuous process for preparing a polystyrene resin having high impact property, high fluidity, excellent gloss and good graft proportion and falling dart impact strength. CONSTITUTION: The high impact polystyrene resin is prepared by continuous process comprising the steps of: (A) reacting a styrene-based monomer and a rubber component at 100-130 deg.C in a first reactor for 1-2 hours to produce a first polymeric product; (B) introducing the first polymeric product into a second reactor successively to produce a second polymeric product; (C) introducing the second polymeric product into a third reactor successively to produce a third polymeric product; (D) introducing the third polymeric product into a fourth reactor successively to produce a fourth polymeric product; and (E) introducing the fourth polymeric product into a volatile matter eliminator to remove unreacted monomer and solvent, thereby obtaining a polyester resin.

Description

Continuous Process for Preparing High Impact Polystyrene Resin

Field of invention

The present invention relates to a continuous manufacturing process of high impact polystyrene (HIPS) resin. More specifically, the present invention relates to a method for producing a high gloss, high flow, and high impact polystyrene resin by controlling the polymerization temperature and residence time of each reactor by connecting four reactors in series.

Background of the Invention

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

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, the resin manufacturer improves the practical impact strength by adding polydimethylsiloxane to the styrene-based resin, such as Japanese Patent Application Laid-Open No. 60-217254, to increase the flexibility of the resin. I've tried to, but I still have a problem. In addition, the conventional technique for increasing the practical impact strength to improve the practical impact strength by dispersing the particle size of the rubber phase, which is a dispersed phase of high-impact polystyrene (HIPS) resin in the form of bimodal or trimodal form High impact polystyrene (HIPS) resins having different rubber particle diameters were previously polymerized and then mixed 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 stage of phase change, but also have disadvantages in that the control for the polymerization is complicated and the practical impact strength is not sufficiently improved.

In addition, as a method for increasing the practical impact strength, there is a method of increasing the binding force of the rubber phase and the polystyrene phase in the continuous phase by improving the graft ratio. In the prior art, an initiator was used to improve the graft ratios of rubber and polyester phases, thereby improving practical impact strength, but continuous bulk polymerization was difficult due to an increase in reactivity due to the use of initiators, and a problem of appearance deterioration. have.

In order to overcome the above problems, the present inventors connect four reactors in series to vary the polymerization conditions of each reactor, and thus have high impact, high flow, or high gloss characteristics, and at the same time, excellent practical impact strength and high graft ratio. We have begun developing a process for the continuous production of high impact polystyrene (HIPS) resins.

An object of the present invention is to provide a continuous method for producing a high impact polystyrene resin with high impact strength.

Another object of the present invention is to provide a continuous production method of high impact polystyrene resin with high fluidity.

Still another object of the present invention is to provide a continuous production method of high impact polystyrene resin having excellent gloss.

Another object of the present invention is to provide a continuous production method of high impact polystyrene resin excellent in graft ratio and practical 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.

In the continuous production method of the high impact polystyrene resin according to the present invention, (A) 85 to 95 parts by weight of the styrene monomer and 5 to 15 parts by weight of the rubber component are mixed and dissolved in a dissolution tank and transferred to the first reactor, followed by a first reactor. Reacting at 100 to 130 ° C. for 1 to 2 hours to a point before the phase change to produce a first polymer having a conversion rate of 5 to 15% of the monomer, (B) continuously introducing the first polymer into the second reactor and then 125 Polymerizing at ˜140 ° C. for 1 to 2 hours to produce a second polymer having a monomer conversion rate of 15 to 30%, (C) continuously adding the second polymer to a third reactor to 0.5 at 140 to 155 ° C. Reacting for ˜1.5 hours to produce a third polymer having a monomer conversion of 30 to 60%, (D) continuously introducing the third polymer to the fourth reactor to provide a respective temperature at four zones within the fourth reactor. 150 over control Reacting in a range of 180 ° C. to produce a fourth polymer having a monomer conversion of 60 to 90%, and (E) adding the fourth polymer to a volatile remover to remove unreacted monomers and solvents, followed by final polystyrene resin. Characterized in that it comprises a step of producing.

Detailed description of each of these steps is as follows.

Preparation of First Polymer

In the manufacturing method of HIPS resin according to the present invention, first, the styrene-based monomer and the rubber are dissolved in the dissolution tank, and then the first reactor is transferred to a full charge reactor.

The styrene monomers include styrene, α-methyl styrene, α-ethyl styrene, p-methyl styrene, and the like. Preferably, the rubber is made of polybutadiene rubber, such as Low Cis Polybutadiene Rubber, High Cis Poly Butadiene Rubber, Styrene-Rubber Copolymer, etc. Use mixed.

In addition, as the solvent according to the present invention, an aromatic compound 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 proceeds at 100 to 130 ° C. for 1 to 2 hours. At this time, the conversion rate is 5 to 15% and the reaction is transferred to the second polymerization reactor after the phase transfer reaction.

The product of the first polymerization reactor is a polystyrene polymerized in a continuous rubber phase in the dispersed 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 to 30%. The second reactor is a continuous flow stirred reactor (CSTR) as a phase transfer reactor.

The polymerization temperature is carried out for 1 to 2 hours at 125 to 140 ℃, the conversion rate is 15 to 30%.

An important role of the second polymerization reactor of the present invention is to disperse the rubber particles on the continuous polystyrene. The reactant of the first polymerization reactor has a polystyrene phase dispersed on the continuous rubber, but the volume volume of the polystyrene produced by the polymerization through the second polymerization reactor and the volume of the initially charged rubber (including polystyrene grafted to rubber) are the same. Phase transition starts at and the rubber dispersed phase is formed in 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 physical properties of the HIPS 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 a reaction temperature of 140 to 155 ° C. for 0.5 to 1.5 hours, and the conversion rate is 30 to 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 of the present invention is divided into four regions 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% to 90% through the fourth reactor is transferred to a devolatilizer to remove unreacted monomers and solvents, thereby preparing a final HIPS resin. The fourth reactor is a final reactor in the polymerization step and polymerizes at a conversion rate of 60 to 90% at a temperature of 150 to 180 ° C.

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

Example

In Examples 1 to 3, high gloss, high flow, and high impact polystyrene resins were prepared in Examples 1 to 3 according to the continuous production method according to the present invention, and the process conditions are shown in Table 1.

Example 1 Continuous Production of High Gloss HIPS

In each reactor was reacted according to the polymerization conditions of Table 1 to prepare a high-gloss HIPS. 89.2 parts by weight of styrene monomer, 5.8 parts by weight of polybutadiene rubber (trade name 730A of Asahi, Japan) and 5.0 parts by weight of solvent and ethyl benzene were dissolved in a complete mixing bath to prepare a reaction raw material solution, which was then supplied to the first reactor. The first reactor was reacted at 116 ° C. for 1 hour. The reactant passed through the first reactor was reacted for 2 hours in a second reactor at 125 ° C. and 50 RPM, and then introduced into the third reactor. The third reactor was continuously charged with 200 ppm / hour of tertiary dodecyl merethane (TDDM), which is a molecular weight regulator, reacted for 0.8 hours at 150 ° C., and then transferred to the fourth reactor. The fourth reactor reacts by raising the temperature step by step, and the reaction temperature is reacted at 161, 168, 175, and 182 ° C, respectively. The polymers passed through the four reactors were removed through pelleting and unreacted monomers and solvent, and then pelletized to prepare a final polymer. Resin characteristic analysis and physical property analysis of the injection molded product were performed on the final polymerized product, and the results are shown in Table 3.

Izod impact strength was measured by ASTM D-256, fluidity by ASTM D-1238, glossiness by ASTM D-523, practical impact strength by ASTM D-3029, and the graft rate (%) can be obtained by Equation 1 below. have.

[Equation 1]

Example 2: Continuous Preparation of High Flow HIPS

In each reactor was reacted according to the polymerization conditions of Table 1 to prepare a high flow HIPS. 88.4 parts by weight of styrene monomer, 6.6 parts by weight of polybutadiene rubber (trade name 730A of Asahi Japan), 5.0 parts by weight of solvent, and ethyl benzene were dissolved in a complete mixing tank to prepare a reaction raw material solution, which was then supplied to the first reactor. In the first reactor, tertiary butyl peroxy acetate as an initiator was reacted at 106 ° C. for 1 hour while continuously inputting 100 ppm per hour. The reactant passed through the first reactor was reacted for 2 hours in a second reactor at 117 ° C. and 70 RPM, and then introduced into the third reactor. The third reactor was continuously charged with 500 ppm per hour TDDM, a molecular weight regulator, and reacted for 0.8 hours at 154 ° C., and then transferred to the fourth reactor. The fourth reactor was reacted by increasing the temperature step by step, and the reaction temperature was reacted at 165, 172, 179, and 186 ° C, respectively. The polymers passed through the four reactors were removed through pelleting and unreacted monomers and solvent, and then pelletized to prepare a final polymer. Resin characteristic analysis and physical property analysis of the injection molded product were performed on the final polymerized product, and the results are shown in Table 2.

Example 3: Continuous Preparation of High Impact HIPS

In each reactor was reacted according to the polymerization conditions of Table 1 to prepare a high-impact HIPS. 85.4 parts by weight of styrene monomer, 9.6 parts by weight of polybutadiene rubber (trade name 710S of Kumho Petrochemical Co., Ltd.), 5.0 parts by weight of solvent, and ethyl benzene were dissolved in a complete mixing tank to prepare a reaction raw material solution, which was then supplied to the first reactor. After the first reactor was reacted at 101 ° C. for 1 hour, the reactants passed through the first reactor were reacted at 119 ° C. for 2 hours in a 70 rpm second reactor, and then introduced into a third reactor. The third reactor was continuously charged with 300 ppm per hour TDDM, a molecular weight regulator, and reacted for 0.7 hours at 161 ° C., and then transferred to the fourth reactor. The fourth reactor was reacted by increasing the temperature step by step, and the reaction temperature was reacted at 152, 154, 156 and 158 ° C, respectively. The polymers passed through the four reactors were removed through pelleting and unreacted monomers and solvent, and then pelletized to prepare a final polymer. Resin characteristic analysis and physical property analysis of the injection molded product were performed on the final polymerized product, and the results are shown in Table 2.

Comparative Example

Using the same raw materials and compounding ratios as in Examples 1 to 3, polymerization was carried out through the second reactor and the third reactor, followed by removal of unreacted monomers and solvents through a volatilization tank, and then pelletized to give high gloss, high flow, and high impact polystyrene resin Was prepared and the process conditions are shown in Table 2.

Comparative Example 1: Continuous manufacture of high gloss HIPS

After the reaction of the second reactor at 130 ° C. and the stirring RPM 60 for 2.1 hours, the reactor was continuously added to the third reactor. After the reaction at 0.8 ° C. for 187 ° C., the final polymerized product was analyzed for resin properties and the injection molded product. The results are shown in Table 3.

Comparative Example 2: High Flow HIPS Continuous Production

After reaction for 2.3 hours at the reaction temperature of the second reactor at 116 ° C., stirring RPM 70, and 200 ppm per hour of initiator, the reactor was continuously added to the third reactor and reacted for 0.6 hours at 199 ° C., followed by analysis of resin properties and physical properties of the injection molded product. The analysis was performed and the results are shown in Table 3.

Comparative Example 3: High Impact HIPS Continuous Production

After 2.1 hours of reaction in the second reactor reaction temperature of 123 ℃, stirring RPM 70, 300 ppm per hour of initiator, the reactor was continuously added to the third reactor and reacted for 0.9 hours at 176 ℃, followed by analysis of resin properties and physical properties of the injection molded product. The analysis was performed and the results are shown in Table 3.

Example One 2 3 First reactor % Conversion 6.3 5.0 5.2 Reaction temperature (℃) 11.6 106 101 Stirring Speed (RPM) 110 110 110 Retention time (hr) One One One Initiator (ppm) - 100 - Molecular weight regulator - - - Second reactor % Conversion 28.2 25.4 30.2 Reaction temperature (℃) 125 117 119 Stirring Speed (RPM) 50 70 70 Retention time (hr) 2 2 2 Third reactor % Conversion 51.2 53.6 64.7 Reaction temperature (℃) 150 154 161 Retention time (hr) 0.8 0.8 0.7 Molecular weight regulator - 500 300

Comparative Example One 2 3 Second reactor Reaction temperature (℃) 130 116 123 Stirring Speed (RPM) 60 70 70 Retention time (hr) 2.1 2.3 2.1 Initiator (ppm) - 200 300 Third reactor Reaction temperature (℃) 187 199 176 Retention time (hr) 0.8 0.6 0.9

Example Comparative Example One 2 3 One 2 3 Impact Strength (kgfcm / cm) 11.5 11.0 16.8 11.7 10.8 15.3 Fluidity (g / 10min, 5kg, 200 ℃) 5.6 14.6 2.5 5.8 14.2 2.7 Glossiness (%, 60 °) 98 - - 97 - - Graft Rate (%) 145 173 162 98 135 127 Practical Impact Strength (J) 7.1 24 27 3.0 18 21

The present invention provides a continuous production method of high impact polystyrene resins having excellent impact strength, fluidity, or glossiness and excellent graft rate and practical impact strength by varying polymerization conditions of each reactor by connecting four reactors in series. It has the effect of the invention.

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.

1 is a process diagram schematically showing a continuous production apparatus for producing a high impact polystyrene resin according to the present invention.

Claims (5)

(A) 85 to 95 parts by weight of the styrene-based monomer and 5 to 15 parts by weight of the rubber component are mixed and dissolved in a dissolution tank, transferred to the first reactor, and then transferred to the first reactor for 1 to 2 hours at 100 to 130 ° C. Reacting to a time point to produce a first polymer having a monomer conversion of 5 to 15%; (B) continuously introducing the first polymer into the second reactor to polymerize at 125 to 140 ° C. for 1 to 2 hours to produce a second polymer having a monomer conversion of 15 to 30%; (C) continuously introducing the second polymer into the third reactor and reacting at 140 to 155 ° C. for 0.5 to 1.5 hours to produce a third polymer having a monomer conversion of 30 to 60%; (D) a fourth polymer having a monomer conversion of 60 to 90% by continuously introducing the third polymer into the fourth reactor and reacting in four regions within the fourth reactor through respective temperature control in the range of 150 to 180 ° C. Producing a polymer; And (E) preparing a final polystyrene resin by adding the fourth polymer to a volatile remover to remove unreacted monomers and solvents; A continuous production method of a high impact polystyrene resin, characterized in that consisting of. The method of claim 1, wherein the first reactor is a full-charge reactor, a continuous flow stirred reactor. The method of claim 1, wherein the second reactor is a continuous flow stirred reactor as a phase transfer reactor. The method of claim 1, wherein the third reactor is a horizontal reactor for producing a flow of a flow of reactants. The method of claim 1, wherein the styrene-based monomer is selected from the group consisting of styrene, α-methyl styrene, α-ethyl styrene, and p-methyl styrene, the rubber component is low seed poly butadiene rubber, high seed poly butadiene rubber And a styrene butadiene copolymer and a mixture of one or two or more selected from the group consisting of high impact polystyrene resins.