KR100893873B1 - Continuous Process for Preparing Thermoplastic Copolymer Resin Having Excellent Heat Resistance - Google Patents

Abstract

The present invention provides a batch polymerization reaction by continuously adding a mixed raw material mixed with an aromatic vinyl monomer containing α-methylstyrene, a vinyl cyanide monomer and a polymerization initiator into a plurality of reactors connected in series; Injecting the reactant to the devolatilizer through a transfer tube to remove the unreacted monomer, maintaining the temperature of the transfer tube at 140 ℃ to 160 ℃, the temperature of the devolatilizer 235 ℃ to 255 ℃ It relates to a continuous production method of a thermoplastic copolymer resin having excellent heat resistance characteristics, characterized in that the control.

Thermoplastic resin, heat resistant copolymer resin, heat resistant ABS resin, continuous bulk polymerization, heat resistance, heat discoloration

Description

Continuous Process for Preparing Thermoplastic Copolymer Resin Having Excellent Heat Resistance

Field of invention

The present invention relates to a method for producing a copolymer resin having excellent heat resistance, and more particularly to a method capable of improving the heat resistance characteristic of a thermoplastic resin used as a matrix resin of a heat resistant ABS (acrylonitrile-butadiene-styrene) resin. It is about.

Background of the Invention

In general, ABS resin has excellent mechanical and thermal properties including physical properties such as processability of styrene, stiffness and chemical resistance of acrylonitrile, impact resistance of butadiene, etc. Although it has the advantage of being widely used in various applications such as devices, general office supplies, home appliances, toys, stationery, etc., this ABS resin is used in products requiring heat resistance such as interior and exterior materials due to heat deformation due to low heat resistance. There is a limit to this.

In order to overcome such low heat resistance, a method of introducing a monomer such as α-methylstyrene or maleimide having excellent heat resistance or adding an inorganic substance to a part of the composition constituting the ABS resin is used.

As another method, there is a method of mixing the heat-resistant copolymer resin containing the monomer having excellent heat resistance with ABS resin or butadiene rubber.

The heat-resistant ABS resin prepared by introducing some of the monomers having excellent heat resistance should not only have excellent heat resistance but also excellent physical properties. In addition, there should be no problems such as decomposition of the resin and discoloration when the product is processed by extrusion, injection, etc. at high temperature.

However, in the case of α-methylstyrene having a very low ceiling temperature (about 60 ° C.) due to the characteristics of the structure, depolymerization is predominant at high polymerization temperatures and polymerization does not occur well, thus making it difficult to increase molecular weight. In addition, due to the geometrical characteristic of the methyl group in the α position, the reaction is subject to a lot of restrictions and the reactivity is low, the content of the unreacted monomer in the resulting copolymer resin is high. These residual unreacted monomers adversely affect the heat resistance and other physical properties of the final product and cause difficulties in processing the product.

In addition, unreacted monomers in the resin are decomposed during molding such as extrusion and injection at a high temperature, causing adverse smells and harmful gas generation. Therefore, in the development of a heat resistant copolymer resin, it is urgent to prepare a countermeasure for the control of the chain structure in the copolymer resin of α-methylstyrene which is poor in reactivity and easily decomposes, and to remove the unreacted monomer in the final product.

Due to the properties of the α-methylstyrene, a method for preparing a heat resistant copolymer resin is usually prepared by emulsion polymerization in a batch process having a low reaction temperature and easy adjustment of reaction time. U.S. Patent No. 3,010,936 and U.S. Patent No. 4,774,287 disclose a process for producing a heat resistant copolymer resin by emulsion polymerization.

However, emulsion polymerization also has some problems. In general, emulsion polymerization has a polymerization, agglomeration, dehydration, and drying process. Therefore, the reaction temperature is lower than that of the bulk polymerization method to improve the molecular weight and heat resistance. However, the heat-resistant copolymer in which the emulsifier and flocculant used in the polymerization process are produced. It acts as an impurity in the resin, and during processing such as extrusion and injection, these impurities are easily decomposed to heat and cause discoloration.

In addition, since the unreacted monomer cannot be recovered due to the process characteristics, the unreacted monomer remains in the product, and the higher the content of the remaining unreacted monomer, the lower the heat resistance characteristics of the heat resistant copolymer resin.

Due to the problems of the emulsion polymerization method described above, a heat-resistant ABS resin produced using a heat-resistant copolymer resin produced by the emulsion polymerization method, when processed by extrusion or injection, inverse odor occurs due to decomposition of the resin, impurities and unreacted monomers. And there is a problem such as thermal discoloration of the injection molding.

In order to solve the problem of the emulsion polymerization method, US Patent No. 4,795,780 discloses a method for producing a heat-resistant copolymer resin by the continuous bulk polymerization method. Continuous bulk polymerization improves productivity through continuous product production without the use of emulsifiers and flocculants that can act as impurities in the resulting copolymer resin. The monomer mixture was continuously introduced into a reactor in which two stirred tank reactors were connected in series to perform a copolymerization reaction, and the monomer recovered from the condenser was returned to the first reactor to match the polymerization composition of low-reactivity α-methylstyrene and acrylonitrile. The method of injecting was devised to overcome the low conversion rate.

In addition, US Patent No. 6,593,424 and Korean Patent No. 0417066 further disclose a method of mixing a monofunctional or polyfunctional initiator that can improve the reactivity.

Since the above patents react at a higher temperature than emulsion polymerization due to the nature of the continuous bulk polymerization method, a solvent is used to prepare a heat resistant copolymer resin by controlling the polymerization temperature and the viscosity of the reactant, but the solvents used are heat resistant copolymer resins. It has been overlooked that it acts as a chain transfer agent in the chain, lowering its molecular weight, thereby lowering its heat resistance characteristics.

In addition, the above patents do not consider the chain scission in the delivery tube when transferring the reactants for the continuous process. Since the transfer pipe connecting the reactor to the reactor, the reactor and the devolatilizer has a small diameter due to the characteristics of the equipment, it receives a high shear stress during the transfer of the highly viscous reactant, resulting in chain breakage of the heat-resistant copolymer resin. The temperature of the feed tube set high for the flow of decomposes the heat resistant copolymer resin along with the shear stress and lowers the molecular weight.

In addition, the conditions of the devolatilizer through which the product passes for the removal of unreacted monomers before obtaining the final heat resistant copolymer resin are important not only in the heat resistance characteristics of the heat resistant copolymer resin, but also in odor and appearance characteristics during extrusion and injection processing. However, there is no mention of these in the above patents.

In preparing a heat-resistant copolymer resin containing α-methylstyrene, the various problems are caused by the properties of the material possessed by the α-methylstyrene monomer. The conventional methods have some effects in solving the problems. There is a limit to fundamental improvement.

In order to improve the heat resistance of the heat resistant copolymer resin, the present inventors can control the chain breakage by controlling the temperature of the transfer tube and the devolatilizer temperature of the continuous bulk polymerization reaction facility to develop a heat resistant copolymer having improved heat resistance. It is early.

An object of the present invention is to provide a method for continuously producing a copolymer resin having excellent heat resistance by the bulk polymerization method.

Another object of the present invention is to provide a continuous manufacturing method of a heat-resistant thermoplastic copolymer resin by inhibiting chain scission (improved heat resistance).

Another object of the present invention is to provide a continuous production method of a heat-resistant thermoplastic copolymer resin without decomposition or thermal discoloration of the resin during processing such as extrusion, injection at high temperature when used as a matrix resin of the heat-resistant ABS resin.

Another object of the present invention is to provide a continuous production method of a heat-resistant thermoplastic copolymer resin having an unreacted monomer content of less than 1500 ppm.

Another object of the present invention is to provide a continuous manufacturing method of environmentally friendly heat-resistant thermoplastic copolymer resin does not generate an adverse odor or flow gas due to the decomposition of impurities, unreacted monomer during processing of the heat-resistant ABS resin using the heat-resistant thermoplastic copolymer resin. It is to.

Another object of the present invention is to provide a continuous production method of a heat-resistant thermoplastic copolymer resin having a weight average molecular weight of 80,000 to 120,000.

The above object of the present invention can be achieved by the present invention described below.

Summary of the Invention

The present invention provides a batch polymerization reaction by continuously adding a mixed raw material mixed with an aromatic vinyl monomer containing α-methylstyrene, a vinyl cyanide monomer and a polymerization initiator into a plurality of reactors connected in series; Injecting the reactant to the devolatilizer through a transfer tube to remove the unreacted monomer, maintaining the temperature of the transfer tube at 140 ℃ to 160 ℃, the temperature of the devolatilizer 235 ℃ to 255 ℃ It relates to a continuous production method of a thermoplastic copolymer resin having excellent heat resistance characteristics, characterized in that the control. The heat-resistant copolymer resin prepared using the method of the present invention has a high heat resistance and has the advantage of reducing physical property changes such as heat discoloration after extrusion and injection molding.

Hereinafter, the content of the present invention will be described in detail below.

Detailed Description of the Invention

In the continuous production method of the thermoplastic copolymer resin of the present invention, a batch polymerization reaction is carried out by continuously adding a mixed raw material mixed with an aromatic vinyl monomer containing α-methylstyrene, a vinyl cyanide monomer and a polymerization initiator to a plurality of reactors connected in series. Injecting the reactant to the devolatilizer through a transfer tube to remove the unreacted monomer, maintaining the temperature of the transfer tube at 140 ℃ to 160 ℃, the temperature of the devolatilizer 235 ℃ to 255 ℃ It is characterized by adjusting to.

The aromatic vinyl monomers may be used alone or in combination of the above-mentioned α-methylstyrene and aromatic vinyl monomers such as styrene, α-ethyl styrene, p-methyl styrene, and vinyl toluene.

Acrylonitrile, methacrylonitrile, or the like may be used as the vinyl cyanide monomer, and these may be used alone or in a mixture. Preferred of these is acrylonitrile.

The ratio of the aromatic vinyl monomer and the vinyl cyanide monomer is not particularly limited, but preferably 60 to 80 parts by weight of the aromatic vinyl monomer and 20 to 40 parts by weight of the vinyl cyanide monomer.

As the polymerization initiator, a peroxide initiator or an AIBN initiator may be used. For example, benzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-bis (t-butylperoxy) cyclohexane (1,1-Bis (t-butylperoxy) cyclohexane), 2,2-bis (4,4-di-t-butylpooxy cyclohexane) propane (2,2-Bis (4,4-di-t-butylperoxy cyclohexane) propane), (t-hexyl per T-Bexyl peroxy isopropyl monocarbonate, t-Butyl peroxylaurate, t-Butyl peroxy isopropyl monocarbonate, t-butyl percarbonate T-Butyl peroxy 2-ethylhexyl monocarbonate, t-hexyl peroxybenzoate, t-Butyl peroxyacetate, 2,2-bis (t-butyl peroxy) butane (2,2-Bis (t-butyl peroxy) butane), t-butyl peroxybenzoate (t-Butyl peroxybenzoate), Dicumyl peroxide, 2,5- Dimethyl-2,5-bis (t-butyl Oxy) hexane (2,5-Dimethyl-2,5-bis (t-butyl peroxy) hexane), t-butyl cumyl peroxide, di-t-butyl peroxide butyl peroxide), Di-t-amyl peroxide, etc., but are not necessarily limited thereto, and may be used alone or in combination.

The polymerization initiator is used in the range of 0.05 to 0.3 parts by weight based on 100 parts by weight of the monomer mixture. If the amount of the polymerization initiator exceeds 0.3 parts by weight, it is difficult to effectively control the reaction temperature, residence time, etc. due to the rapid polymerization reaction, the molecular weight of the resulting polymer is lowered, the heat resistance may be lowered, less than 0.05 parts by weight In use, the polymerization reaction rate is lowered and the conversion rate to the polymer is lowered, thereby lowering productivity.

The reactor of the present invention uses 2 to 10 reactors, preferably 2 to 6 reactors. The plurality of reactors are preferably connected in series with each other.

It is preferable that the conversion rate of the monomer converted to the polymer is controlled to less than 30% while passing through each continuous polymerization reactor, and the final conversion rate after passing through the last reactor is 50% to 70%. If the conversion is more than 30%, the content of relatively reactive acrylonitrile increases in the resulting polymer chain, thereby lowering the heat resistance characteristics and generating a substance such as a gel insoluble in the solvent. In addition, when the conversion rate is increased to more than 30%, it is difficult to transfer due to the rise of the viscosity of the resin in the continuous bulk polymerization process without using a solvent. In order to maintain the conversion rate in the reactor at a level of less than 30%, the reaction temperature, residence time, type and content of the polymerization initiator may be adjusted.

In the embodiment of the present invention, it is preferable to maintain the temperature conditions inside the respective reactors from 110 ℃ to 130 ℃. If the reaction temperature is less than 110 ℃ the polymerization reaction is not active, the conversion rate into the polymer is low, the productivity may be lowered. If the reaction temperature exceeds 130 ℃, the conversion rate to the polymer is increased due to the rapid reaction, The viscosity may increase, making transfer difficult in subsequent processes. In addition, the high temperature reaction results in lower molecular weight, resulting in lower heat resistance and physical properties of the copolymer resin.

In an embodiment of the invention the total residence time through each reactor is adjusted to 4 to 6 hours. Final conversion after the last reactor is between 50% and 70%.

The reactant is fed to the devolatilizer through a transfer tube. At this time, the transfer tube temperature is maintained at 140 ℃ to 160 ℃. If the conveying tube temperature is lower than 140 ℃, the viscosity of the resin to be conveyed becomes high, the flowability is poor and smooth conveyance is not achieved, if the conveying tube temperature between the reactor and the devolatilizer is higher than 160 ℃, chain breakage occurs It lowers the molecular weight and eventually lowers the heat resistance characteristics.

The devolatilizer removes unreacted monomers, and the temperature of the devolatilizer is adjusted to 235 ° C to 255 ° C. If the temperature of the devolatilizer is lower than 235 ° C, the content of unreacted monomers in the resulting copolymer resin is increased, which adversely affects the heat resistance and physical properties of the heat-resistant copolymer resin. If the temperature is higher than 255 ° C, thermal decomposition of the resin occurs due to high temperature. It affects physical properties such as heat discoloration and heat resistance.

Since this invention does not use a solvent, a copolymer resin with a heat resistance of 115 degreeC or more can be obtained without a molecular weight falling.

In one embodiment of the present invention, the copolymer resin has a weight average molecular weight of 80,000 to 120,000, and a heat resistance measured at 5 kgf and 50 ° C./hr according to ISO R306 at 115 to 120 ° C.

In addition, the copolymer resin prepared through the production method of the present invention can reduce the unreacted monomer content in the copolymer resin produced by the temperature condition of the devolatilizer to 235 ℃ to 255 ℃ to less than 1500 ppm, and improve the heat resistance characteristics of the copolymer resin It can improve physical properties such as thermal discoloration after extrusion and injection molding.

The thermoplastic copolymer resin having excellent heat resistance characteristics according to the present invention may be used as a matrix resin of a heat resistant ABS (acrylonitrile-butadiene-styrene) resin to prepare a heat resistant ABS resin.

In one embodiment, the heat-resistant ABS resin is composed of 50 to 90 parts by weight of acrylonitrile-butadiene-styrene graft copolymer in 10 to 50 parts by weight of the thermoplastic copolymer resin prepared by the above method.

In another embodiment, the heat-resistant ABS resin is 20-50 parts by weight of the thermoplastic copolymer resin prepared by the above method, 20-40 parts by weight of acrylonitrile-butadiene-styrene graft copolymer and 20-40 parts of acrylonitrile-styrene copolymer. It consists of parts by weight.

The heat resistant ABS resin of the present invention may include general additives such as flame retardants, flame retardant aids, lubricants, mold release agents, nucleating agents, antistatic agents, stabilizers, organic or inorganic reinforcing materials, pigments or dyes according to the respective applications, the general additives added It can be used in the range of 0 to 40 parts by weight, preferably 0.01 to 20 parts by weight based on 100 parts by weight of the thermoplastic copolymer resin.

The heat-resistant ABS resin using the thermoplastic copolymer resin of the present invention as a matrix resin has excellent heat resistance, generates little toxic gas during processing, and does not cause discoloration.

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

Preparation of heat resistant copolymer resin

Example  One

70 parts by weight of α-methylstyrene, 30 parts by weight of acrylonitrile, and 1,1-bis (t-butylperoxy) cyclohexane (1,1-Bis) in a continuous polymerization apparatus in which two 2L and 3L reactors were connected in series. 0.15 parts by weight of t-butylperoxy) cyclohexane) was mixed uniformly, and then the mixture was continuously introduced at a constant rate into the first reactor to polymerize at a conversion rate of 30%, and the final conversion rate through the second reactor was 60%. Continuous bulk polymerization was carried out for a total of 5 hours. At this time, the reaction temperature was maintained at 115 ℃. The temperature of the tube in which the reactant is transferred to the devolatilizer in the last reactor is maintained at 150 ° C, and the transferred reactant is removed from the unreacted monomer at a temperature of 245 ° C and a vacuum pressure of 20 torr in the devolatilizer to which the heat exchanger is attached. Processed in pellet form.

The molecular weight, heat resistance, and residual monomer content of the heat-resistant copolymer resin processed into the pellets were measured by the following method.

(1) Molecular weight: After melting in a solvent, polystyrene was used as a reference and measured using gel chromatography.

(2) Heat resistance (Vicat Softening Temperature): According to ISO R306, it was measured under conditions of elevated temperature of 5 kgf and 50 ° C / hr.

(3) Residual monomer content: After heat-resistant copolymer resin pellets were melted in a solvent, they were measured by gas chromatography.

Comparative Example  One

70 parts by weight of α-methylstyrene and 30 parts by weight of acrylonitrile were added to a reactor equipped with a stirrer capable of withstanding 10 liters of pressure, and 0.5 parts by weight of initiator 1,1-bis (t-butylperoxy) cyclohexane. After the addition, the reactor was completely sealed, and then sufficiently substituted with nitrogen and stirred inside. After sufficiently stirring to confirm dispersibility, the temperature inside the reactor was raised to 95 ° C and polymerized for 12 hours. After completion of the polymerization, the inside of the reactor was cooled to terminate the reaction, and the obtained polymer was washed, dehydrated, and dried to prepare a heat resistant copolymer resin.

Comparative Example  2

The same process as in Example 1 was carried out except that the temperature of the feed tube between the reactor and the devolatilizer was operated at 185 ° C. and the devolatilizer temperature was 230 ° C.

Comparative Example  3

The same process as in Example 1 was carried out except that the temperature of the feed tube between the reactor and the devolatilizer was operated at 185 ° C. and the devolatilizer temperature was set at 260 ° C.

Comparative Example  4

Except for adding 10 parts by weight of methyl ethyl ketone to the same monomer composition as in Example 1 was carried out in the same manner as in Example 1.

The physical properties of the heat-resistant copolymer resin prepared in Examples and Comparative Examples above are shown in Table 1 below.

TABLE 1

Production of heat resistant ABS resin

Example  2

30 parts by weight of the polybutadiene rubber-grafted copolymer prepared by emulsion polymerization and 30 parts by weight of the general styrene-acrylonitrile copolymer resin were mixed with 40 parts by weight of the pellet prepared in Example 1, and 0.1 parts by weight of octadecyl 3- (3,5-di-tert butyl-4-hydroxyphenyl) propionate (Octadecyl 3- (3,5-di-tert butyl-4-hydroxyphenyl) propionate) 0.1 parts by weight of di-stearyl pentaeryl diphosphite, 0.3 parts by weight of chlorinated polyethylene, 0.02 parts by weight of dimethyl polysiloxane, decandioic acid bis (2,2) 0.15 parts by weight of 6,6-tetramethyl-4-piperidinyl) ester (2,2,6,6-tetramethyl-4-piperidinyl) ester was added. The mixture was made of a heat resistant ABS resin in pellet form using a twin screw extruder at 250 ° C. cylinder temperature. The flow index was measured according to ASTM D1238 (220 ℃, 10kg) with the manufactured heat-resistant ABS resin, the impact strength was measured according to ASTM D256, and the yellowness was obtained with the sheet specimen of 3mm thickness using the colorimeter set in the reflection mode. Was measured. The heat resistance (Vicat Softening Temperature) was measured under a temperature condition of 5kgf, 50 ℃ / hr according to ISO R306.

The polybutadiene rubber-grafted copolymer used in the heat-resistant ABS resin manufacturing process of Example 2 was prepared as follows.

Butadiene rubber latex was added so that the butadiene content was 58 parts by weight based on the total amount of monomers, 1 part by weight of potassium oleate, cumene hydroperoxide, an additive necessary for a mixture of 31 parts by weight of styrene, 11 parts by weight of acrylonitrile, and 150 parts by weight of deionized water. After adding 0.4 parts by weight, 0.3 parts by weight of t-dodecyl mercaptan chain transfer agent and reacted while maintaining at 75 ℃ for 5 hours to prepare an ABS graft copolymer. A 1% sulfuric acid solution was added to the resulting polymer latex, solidified and dried to prepare a rubber-modified vinyl graft copolymer resin having a core-shell form having an average particle diameter of 0.3 μm in powder form.

The styrene-acrylonitrile copolymer resin used in the heat-resistant ABS resin manufacturing process of Example 2 was prepared as follows.

To a mixture of 71 parts by weight of styrene, 29 parts by weight of acrylonitrile and 120 parts by weight of deionized water, 0.17 part by weight of azobisisobutyronitrile, 0.4 part by weight of t-dodecyl mercaptan chain transfer agent and 0.5 part by weight of tricalcium phosphate were added. Suspension polymerization was carried out for 5 hours at ℃ to prepare a SAN copolymer resin. The copolymer was washed with water, dehydrated and dried to obtain a SAN copolymer resin in powder form.

compare Example  5

A heat-resistant ABS resin in the form of pellets was prepared in the same manner as in Example 2 except that the heat-resistant copolymer resin processed into the pellets prepared in Comparative Example 1 was used.

compare Example  6

A heat-resistant ABS resin in the form of pellets was prepared in the same manner as in Example 2 except that the heat-resistant copolymer resin processed into the pellets prepared in Comparative Example 2 was used.

compare Example  7

A heat-resistant ABS resin in the form of pellets was prepared in the same manner as in Example 2 except that the heat-resistant copolymer resin processed into the pellets prepared in Comparative Example 3 was used.

compare Example  8

A heat-resistant ABS resin in the form of pellets was prepared in the same manner as in Example 2 except that the heat-resistant copolymer resin processed into the pellets prepared in Comparative Example 4 was used.

Physical properties of the heat resistant ABS resin are shown in Table 2 below.

TABLE 2

In Examples 1 and 2, as shown in Table 1 and Table 2, a heat resistant copolymer resin having excellent heat resistance characteristics and a heat resistant ABS resin prepared using the same could be prepared. Comparative Examples 1 and 5 are manufactured by a batch process, and have high molecular weight and excellent heat resistance in the process characteristics, but have a high number of unreacted monomers, and thus undergo several processing to show high yellowness due to heat discoloration. The degradation of was observed.

Although there is no difference in composition, in the case of Comparative Example 2 in which the temperature of the transfer tube between the reactor and the devolatilizer is 160 ° C. or higher and the temperature of the devolatilizer is 235 ° C. or lower, the chain cutting phenomenon occurs in the transfer tube between the reactor and the devolatilizer. It was found that the molecular weight is lowered and the heat resistant properties of the heat resistant copolymer resin and the heat resistant ABS resin of Comparative Example 6 prepared using the same were not reduced because the unreacted monomer was not effectively removed from the devolatilizer.

In addition, in the case of Comparative Example 3 manufactured by the temperature of the transfer tube between the reactor and the devolatilizer being 160 ° C. or higher, and the temperature of the devolatilizer operating at the temperature of 255 ° C. or higher, the chain cutting phenomenon occurred in the transfer tube between the reactor and the devolatilizer. Due to the decrease in molecular weight, it was observed that the thermal discoloration and the heat resistance of the heat-resistant ABS resin of Comparative Example 7 prepared by using the same due to the thermal decomposition of the resin in the devolatilizer.

In Comparative Example 4, the solvent used for the reaction temperature control and process stabilization under the same conditions as in Example 1 lowered the molecular weight by acting as a chain transfer agent, and thus the heat resistant copolymer resin and the heat resistant ABS of Comparative Example 8 prepared using the same. It was observed that the heat resistance and the physical properties of the resin were reduced.

When using the heat-resistant copolymer resin prepared by the production method of the present invention as a matrix resin of the heat-resistant ABS resin through the above examples and comparative examples it was confirmed that a product having excellent heat resistance characteristics can be prepared.

The present invention provides an effect of providing a method for continuously producing a copolymer resin having excellent heat resistance characteristics which can improve the change in the heat resistance and physical properties such as heat discoloration after extrusion and injection molding of a thermoplastic resin used as a matrix resin of a heat resistant ABS resin. Has

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)

A bulk polymerization reaction is continuously carried out by continuously adding a mixed raw material in which an aromatic vinyl monomer including α-methylstyrene, a vinyl cyanide monomer and a polymerization initiator are mixed into a plurality of reactors connected in series; Injecting the reactants into the devolatilizer through a transfer pipe to remove unreacted monomers; Consisting of a step, the temperature of the transfer pipe is maintained at 140 ℃ to 160 ℃, the temperature of the devolatilizer is continuous manufacturing method of the thermoplastic copolymer excellent in heat resistance, characterized in that to adjust the temperature to 235 ℃ to 255 ℃. The method of claim 1, wherein the aromatic vinyl monomer is selected from the group consisting of styrene, α-methylstyrene, α-ethyl styrene, p-methyl styrene or vinyl toluene; The vinyl cyanide monomer is a continuous method of producing a thermoplastic copolymer resin having excellent heat resistance, characterized in that selected from the group consisting of acrylonitrile, methacrylonitrile and mixtures thereof. The thermoplastic copolymer of claim 1, wherein the aromatic vinyl monomer is 60 to 80 parts by weight, the vinyl cyanide monomer is 20 to 40 parts by weight, and the polymerization initiator is used in the range of 0.05 to 0.3 parts by weight. Continuous production method of resin. The method of claim 1, wherein each of the reactors are polymerized at a conversion rate of less than 30% and the final conversion rate after the final reactor is 50 to 70%, characterized in that the continuous production method of thermoplastic copolymers having excellent heat resistance characteristics. The method of claim 1, wherein the temperature conditions inside the reactors are maintained at 110 ° C to 130 ° C. The method of claim 1, wherein the total residence time through each of the reactors is 4 to 6 hours. The weight average molecular weight prepared according to the method of any one of claims 1 to 6 is 80,000 to 120,000, and the heat resistance measured under the conditions of 5kgf, 50 ℃ / hr according to ISO R306 is 115 ~ 120 ℃ Thermoplastic copolymer resin with excellent heat resistance.