KR20030022947A - Method for preparing thermoplastic resin having superior gloss and snow whiteness - Google Patents

Abstract

PURPOSE: A method for preparing an ABS-based thermoplastic resin is provided, to improve the brilliance and the whiteness without deterioration of the impact resistance, the chemical resistance and the formability. CONSTITUTION: The method comprises the steps of adding 11-25 parts by weight of an aromatic vinyl compound and 3-16 parts by weight of a vinyl cyano compound to 45-75 parts by weight of a large-caliber rubber latex continuously or separately and graft polymerizing them firstly; adding 6-15 parts by weight of an aromatic vinyl compound and 1-4 parts by weight of a vinyl cyano compound to the obtained graft polymer continuously or separately and graft polymerizing them secondly. Preferably the large-caliber rubber latex has a particle size of 2,500-4,000 Angstrom, a gel content of 70-95 and a swelling index of 12-30; the aromatic vinyl compound is at least one selected from the group consisting of styrene, α -methylstyrene, o-ethylstyrene, p-ethylstyrene, vinyl toluene and their derivatives; and the vinyl cyano compound is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile and their derivatives.

Description

Manufacturing method of thermoplastic resin excellent in gloss and whiteness {METHOD FOR PREPARING THERMOPLASTIC RESIN HAVING SUPERIOR GLOSS AND SNOW WHITENESS}

The present invention relates to a method for producing a thermoplastic resin, and more particularly, to a method for producing a thermoplastic resin having excellent glossiness and whiteness while being excellent in impact resistance, chemical resistance, molding processability, and the like.

Acrylonitrile-butadiene-styrene copolymer (hereinafter referred to as ABS resin) thermoplastic resin has excellent physical properties such as impact resistance, chemical resistance, molding processability, and is widely used in office equipment, electric / electronic parts, automobile interior materials, and the like. Methods for producing these are disclosed in US Pat. Nos. 3,928,494, 4,520,165, 5,955,540, 5,910,538, and European Patent Publication No. 0288298A. These technologies introduce techniques for improving physical properties such as impact strength, processability, glossiness, heat resistance, etc., but there is no mention of a technique for producing ABS resin having excellent glossiness and whiteness at the same time.

In general, the ABS resin is produced by the emulsion polymerization method, and part of it is produced by the bulk polymerization method. In the emulsion polymerization method, the graft ABS copolymer is prepared by the emulsion polymerization method, and the styrene-acrylonitrile copolymer (hereinafter referred to as SAN) prepared by the bulk polymerization method is finally mixed to prepare an ABS resin. ABS resin produced by this manufacturing method is excellent in impact resistance, processability, chemical resistance, glossiness, etc., but has physical properties such as whiteness and thermal stability due to the use of emulsifier and flocculant.

On the other hand, the ABS resin produced by the bulk polymerization method has excellent whiteness, processability, and thermal stability, but has a limited glossiness due to the use of large diameter rubber, and has a limited physical property such as impact resistance because it cannot contain a certain amount of rubber due to viscosity problems. Has

In view of the problems of the prior art, an object of the present invention is to provide a method for producing a thermoplastic resin that is excellent in impact resistance, chemical resistance, molding processability, and the like, and has excellent glossiness and whiteness.

In order to achieve the above object, the present invention provides an ABS thermoplastic resin comprising kneading an acrylonitrile-butadiene-styrene graft copolymer prepared by emulsion polymerization and a styrene-acrylonitrile copolymer prepared by bulk polymerization. In the manufacturing method of

The acrylonitrile-butadiene-styrene graft copolymer

a) first graft polymerization of 11 to 25 parts by weight of aromatic vinyl compound and 3 to 16 parts by weight of vinyl cyan compound in a continuous or divided dose to 45 to 75 parts by weight of large-diameter rubber latex; And

b) performing secondary graft polymerization by continuously or separately adding 6-15 parts by weight of aromatic vinyl compound and 1-4 parts by weight of vinylcyan compound to the first graft polymer;

It provides a method for producing an ABS-based thermoplastic resin produced by a method comprising a.

Hereinafter, the present invention will be described in detail.

In the present invention, in order to manufacture an ABS resin having excellent gloss, whiteness, thermal stability, and the like at the same time by using an emulsion polymerization method, the rubber content is controlled as much as possible by controlling the particle size and gel content of the rubber used and grafting on the rubber. The graft ABS copolymer is manufactured by changing the composition ratio and administration method of styrene and acrylonitrile compound to be used (high rubberized) and grafted, and kneaded with general SAN manufactured by bulk polymerization method to be impact resistant, ABS resin has excellent chemical resistance, molding processability and excellent gloss and whiteness.

In the present invention, the rubber content, particle size, gel content and the like of the rubber latex used when preparing the ABS graft copolymer are very important for whiteness and glossiness. When the rubber content is low, the styrene and acrylonitrile compounds are relatively high, which makes the grafting a lot. However, the gloss is excellent, but when the final ABS resin is kneaded with a general SAN, the emulsifier is included in the product. And a problem that thermal stability is lowered, and if the rubber content is too large, styrene and acrylonitrile compounds are relatively low, so that grafting is not good, and thus glossiness is deteriorated. In addition, when the rubber particle size is large, a resin having excellent impact strength can be obtained, but glossiness is lowered due to a decrease in graft ratio. On the contrary, when the rubber particle size is small, the gloss is excellent but the impact strength is lowered. In addition, if the gel content is high, the styrene-acrylonitrile compound that swells into the rubber particles during grafting is less, so the glossiness is excellent, but the impact resistance is lowered. It has a problem of deterioration.

In addition, the method of administration of the reactants is very important. If grafting continues with a certain ratio of styrene and acrylonitrile compounds, the acrylonitrile component increases relatively as the reaction proceeds due to the difference in the reactivity ratio of the two components. Since the graft copolymer containing a relatively large number of ronitrile compounds is produced, the whiteness is lowered.

Hereinafter, the present invention will be described in more detail.

The present invention comprises a process for producing a rubber latex, a process for producing an ABS graft copolymer grafted with styrene and an acrylonitrile compound, a kneading process and the like.

First, the rubber latex manufacturing process will be described.

(Manufacture of rubber latex)

Rubber latex is made of large-diameter rubber latex after making the small-diameter rubber latex.

<Small Diameter Rubber Latex Manufacturing Process>

The small-diameter rubber latex used in the production of the large-diameter rubber latex of the present invention is a conjugated diene polymer such as an aliphatic conjugated diene compound or a mixture of an aliphatic conjugated diene compound and an ethylenically unsaturated compound, and preferably has a particle diameter of 600 to 1500 Pa. The gel content is 70 to 95% by weight, the swelling index is preferably 12 to 30. If the gel content is 95% by weight or more, the impact strength is lowered. If the gel content is 70% or less, the glossiness is deteriorated.

The specific manufacturing process of the small diameter rubber latex is as follows.

100 parts by weight of conjugated diene, 1 to 4 parts by weight of emulsifier, 0.1 to 0.6 parts by weight of polymerization initiator, 0.1 to 1.0 parts by weight of electrolyte, 0.1 to 0.5 parts by weight of molecular weight regulator, 90 to 130 parts by weight of ion-exchanged water, Reaction at 50 to 65 ° C. for hours

Next, 0.05 to 1.2 parts by weight of a molecular weight modifier was further added in a batch to react at 55 to 70 ° C. for 5 to 15 hours to have an average particle size of 600 to 1500 kPa, a gel content of about 70 to 95 wt%, and a swelling index. To prepare a small diameter conjugated diene rubber latex of about 12 to 30.

The emulsifiers used in the production of such small-diameter latexes may be alkyl aryl sulfonates, alkali methyl alkyl sulfates, sulfonated alkyl esters, fatty acid soaps, alkali salts of rosin acids, and the like. Can also be used.

As the polymerization initiator, a water-soluble persulfate or a peroxy compound can be used, and an oxidation-reduction system can also be used. The most suitable water-soluble persulfate is sodium or potassium persulfate, and fat-soluble polymerization initiators include cumenehydro peroxide, diisopropyl benzenehydroperoxide, azobis isobutylnitrile, tertiary butyl hydroperoxide and paramethane hydroperoxide. , Benzoyl peroxide and the like can be used alone or as a mixture of two or more thereof.

As electrolyte, KCl, NaCl, KHCO ₃ , NaHCO ₃ , K ₂ CO ₃ , Na ₂ CO ₃ , KHSO ₃ , NaHSO ₃ , K ₄ P ₂ O ₇ , K ₃ PO ₄ , Na ₃ PO ₄ , K ₂ HPO ₄ , Na ₂ HPO ₄ and the like can be used alone or in mixture of two or more thereof.

The said molecular weight regulator is preferably mercaptans.

Polymerization temperature and molecular weight modifiers are very important to control the gel content and swelling index of rubber latex, and initiator selection should also be considered.

<Large Diameter Rubber Latex Manufacturing Process (Small Diameter Rubber Latex Fusion Process)>

Since the large-diameter rubber latex particle diameter imparts high impact to the thermoplastic resin, its preparation is very important, and the particle size required to satisfy the physical properties in the present invention is suitably about 2500 to 4000 mm 3.

The specific manufacturing process of the large diameter rubber latex (small diameter rubber latex fusion process) is as follows.

The particle size was 600 to 1500Å, the gel content was 70 to 95% by weight and the swelling index 12 to 30 parts by weight of the small diameter rubber latex 2.5 to 4.5 parts by weight of acetic acid aqueous solution was gradually administered for 1 hour to enlarge the particles and then stirred By fusion to prepare a large diameter conjugated diene rubber latex for ABS graft copolymer having a particle diameter of 2500 to 4000 mm 3, a gel content of 70 to 95 wt%, and a swelling index of 12 to 30.

(Preparation of ABS Graft Copolymer)

The large-diameter rubber latex prepared by the above method is graft copolymerized with an aromatic vinyl compound and a vinyl cyan compound. In the graft polymerization, 0.2 to 0.6 parts by weight of an emulsifier, 0.2 to 0.6 parts by weight of a molecular weight regulator, 0.1 to 0.5 parts by weight of a polymerization initiator and the like are added to 45 to 75 parts by weight of a large diameter rubber latex.

At this time, the polymerization temperature is 45 to 80 ℃ is suitable, the polymerization time is suitable for 3 to 5 hours. The method of adding each component during graft polymerization is to administer each component in a batch, to divide into multiple stages, to continuously administer, and to control the ratio of each component during administration in consideration of the reactivity ratio of each component. There may be a method, but in order to improve the graft rate and to minimize the formation of coagulum, a multistage divided dose method or a continuous dose method is preferable. In particular, in order to prevent the problem that the acrylonitrile component enters a lot and lowers the whiteness, a method in which a large amount of acrylonitrile component having a low reactivity ratio is initially added and a small amount is added to the second half of the reaction.

To this end, a) 11 to 25 parts by weight of the aromatic vinyl compound and 3 to 16 parts by weight of the vinyl cyan compound are continuously or dividedly injected into 45 to 75 parts by weight of the large-diameter rubber latex, and the first graft polymerization is carried out to the primary graft polymer. 6 to 15 parts by weight of the aromatic vinyl compound and 1 to 4 parts by weight of the vinyl cyan compound are continuously or partially charged to prepare a graft copolymer to produce an ABS graft copolymer.

Emulsifiers used in such polymerization reactions are alkylaryl sulfonates, alkali methylalkyl sulfates, sulfonated alkyl esters, soaps of fatty acids, alkali salts of rosin acids, and the like, and these may be used alone or as a mixture of two or more thereof. .

As the molecular weight regulator, tertiary dodecyl mercaptan is mainly used.

Polymerization initiators include peroxides such as cumenehydroperoxide, diisopropylbenzenehydroperoxide, persulfate, sodium formaldehyde succilate, sodium ethylenediamine tetraacetate, ferrous sulfate, dextrose, sodium pyrrolate, sodium sulfite Oxidation-reduction catalyst systems in admixture with reducing agents such as and the like can be used.

The polymerization conversion rate of the latex obtained after the completion of the polymerization was 96% or more, and an antioxidant and a stabilizer were administered to the latex to coagulate with an aqueous sulfuric acid solution at a temperature of 80 ° C. or higher, followed by dehydration and drying to obtain a powder. Stability of the graft copolymer latex prepared above was determined by measuring the solidified solid content (%) as shown in Equation 1 below.

[Equation 1]

When the solid coagulum is 0.7% or more, latex stability is extremely low and a large amount of coagulum makes it difficult to obtain a graft polymer suitable for the present invention.

In addition, the graft ratio of the graft polymer is measured as follows. The graft polymer latex is coagulated, washed, and dried to obtain a powder form, 2 g of this powder is placed in 300 ml of acetone and stirred for 24 hours. The solution is separated using an ultracentrifuge, and then the separated acetone solution is dropped in methanol to obtain an ungrafted portion, which is dried and weighed. From these weights, the graft ratio is calculated according to the following equation.

[Equation 2]

At this time, if the graft ratio is 25% or less, the glossiness is lowered, which is not preferable.

(Kneading process)

General SAN (LG product, Grade name: 80HF, prepared by a bulk polymerization method), a lubricant, an antioxidant, and a light stabilizer were added to the ABS graft copolymer prepared above, and then 200 to 200 using a twin screw extruder. The pellet is prepared by kneading at 210 ° C. to produce the final ABS resin.

Physical properties were measured by injecting this pellet again. General physical properties were measured by the ASTM method, and the whiteness was measured by a Hunter (Hunter Lab.) Colorimeter (manufactured by Hunter Lab., USA) and compared.

In this case, in order to manufacture ABS-based resin having excellent whiteness, many general SANs without emulsifiers should be used. Therefore, a large amount of rubber is required when manufacturing ABS graft polymer, and thus, a large amount of general SAN may be contained in rubber having the same content in the final product. You should be able to.

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

(Manufacture of rubber latex)

a) Preparation of small diameter rubber latex

In a nitrogen-substituted polymerization reactor (autoclave) 100 parts by weight of ion-exchanged water, 100 parts by weight of 1,3-butadiene as monomer, 1.2 parts by weight of potassium rosin salt as emulsifier, 1.5 parts by weight of potassium oleate salt, sodium carbonate as electrolyte ₂ CO ₃ ) 0.1 parts by weight, 0.5 parts by weight of potassium hydrogen carbonate (KHCO ₃ ), 0.3 parts by weight of tertiary dodecyl mercaptan (TDDM) as a molecular weight regulator, and the reaction temperature was raised to 55 ℃, persulfate as an initiator 0.3 parts by weight of potassium was administered in a batch to initiate the reaction. After reacting for 10 hours, 0.05 parts by weight of tertiary dodecyl mercaptan was further administered again, and the reaction was terminated after reacting at 65 ° C. for 8 hours.

The particle size of the obtained small-diameter rubber latex was 1000 GPa, the gel content was 90%, the swelling index was 18.

The gel content, swelling index, and particle size of the small-diameter rubber latex were measured by the following method.

(Gel content and swelling index)

The rubber latex was coagulated with dilute acid or metal salt and washed, dried in a vacuum oven at 60 ° C. for 24 hours, and the resulting rubber mass was chopped with scissors, and then 1 g of the rubber piece was placed in 100 g of toluene for 48 hours. After storage in a dark room room temperature, the sol and the gel are separated and the gel content and the swelling index are measured according to the following Equations 3 and 4 below.

[Equation 3]

[Equation 4]

The particle diameter was measured using a Nicomp 370 HPL (manufactured by Nicomp, USA) by the dynamic laser light skating method.

b) Preparation of large diameter rubber latex (fusion of small diameter rubber latex)

100 parts by weight of the small-diameter rubber latex prepared above was added to the reactor, the stirring speed was adjusted to 10 rpm, and the temperature was adjusted to 30 ° C., and then 3.0 parts by weight of 7% by weight of acetic acid aqueous solution was gradually added for 1 hour, and then the stirring was stopped. And left for 30 minutes to fuse a small diameter rubber latex to prepare a large diameter conjugated diene rubber latex. The large-diameter rubber latex prepared by the fusion process was analyzed.

The rubber latex obtained at this time had a particle diameter of 3100 mm 3, a gel content of 90% and a swelling index of 17.

(Preparation of ABS Graft Copolymer)

60 parts by weight of the large-diameter rubber latex prepared by the fusion method in the nitrogen-substituted polymerization reactor, 65 parts by weight of ion-exchanged water, 0.35 parts by weight of potassium rosinate emulsifier, 0.1 parts by weight of sodium ethylenediaminetetraacetate, 0.005 parts by weight of ferrous sulfate And 0.23 parts by weight of formaldehyde sodium sulfoxylate were administered to a batch reactor, and the temperature was raised to 70 ° C. In addition, 40 parts by weight of ion-exchanged water, 0.5 parts by weight of potassium rosinate, 19.2 parts by weight of styrene, 8.2 parts by weight of acrylonitrile, 0.3 parts by weight of T-dodecyl mercaptan, and 0.3 parts by weight of diisopropylene hydroperoxide were mixed. After continuous addition for 10 hours, 10 parts by weight of ion-exchanged water, 0.1 parts by weight of potassium rosinate, 9.6 parts by weight of styrene, 3.0 parts by weight of acrylonitrile, 0.1 parts by weight of T-dodecyl mercaptan, and diisopropylene hydride 0.1 parts by weight of the mixed emulsion of loperoxide was continuously added for 1 hour, and then heated to 80 ° C, and aged for 1 hour to terminate the reaction.

At this time, the polymerization conversion rate was 97.5% by weight, solid coagulation content was 0.2%, graft rate was 37%.

The latex was also coagulated with an aqueous sulfuric acid solution, washed, and then a powder was obtained.

(Kneading)

0.5 parts by weight of lubricant, 0.3 parts by weight of antioxidant, 0.1 parts by weight of light stabilizer was added to 30 parts by weight of the ABS graft copolymer prepared by the above method and 70 parts by weight of general SAN (Grdae name: 80HF), followed by kneading. Pellets were prepared using a screw extruder, the pellets were injected again to measure physical properties, and the results are shown in Table 1 below.

Comparative Example 1

(Manufacture of large diameter rubber latex)

A large diameter rubber latex was prepared in the same manner as in Example 1.

(Preparation of ABS Graft Copolymer)

76 parts by weight instead of 60 parts by weight of the large diameter rubber latex used in the ABS graft copolymer process, 19.2 parts by weight of styrene used in the first step of the reaction, 8.2 parts by weight of styrene instead of 8.2 parts by weight of acrylonitrile ABS graft copolymer was prepared in the same manner as in Example 1, except that 4.2 parts by weight of nitrile was used. The graft rate at this time was 24%.

(Kneading)

In the kneading process, kraft ABS copolymer was kneaded in the same manner as in Example 1 except for kneading using 25 parts by weight instead of 30 parts by weight and 75 parts by weight instead of general SAN 70 parts by weight.

The physical property results compared are shown in Table 1.

As a result of the physical property comparison, gloss was decreased due to the low graft ratio.

Comparative Example 2

In the same manner as in Example 1, 40 parts by weight instead of 60 parts by weight of the large diameter rubber latex used in the graft ABS copolymer process, 19.2 parts by weight of styrene used in the first step of the reaction, acrylonitrile 8.2 A comparison was made using 33.2 parts by weight of styrene and 14.2 parts by weight of acrylonitrile instead of parts by weight. The graft rate at this time was 45%. In the kneading process, the graft ABS copolymer was kneaded using 45 parts by weight instead of 30 parts by weight and 55 parts by weight instead of 70 parts by weight of a general SAN. The physical property results compared are shown in Table 1.

As a result of the physical property comparison, the low rubber content of the graft ABS copolymer contained a large amount of copolymer prepared by emulsion polymerization during the production of the final ABS resin, resulting in a decrease in whiteness due to the emulsifier and the flocculant.

Comparative Example 3

The same method as in Example 1 was carried out, but the styrene and acrylonitrile compound used in the graft ABS copolymer process were mixed in two stages, mixed at once, and reacted for 3 hours while continuously being administered at the same ratio. The physical property results compared are shown in Table 1.

As a result of the physical property comparison, a copolymer containing a large amount of acrylonitrile component was prepared in the latter part of the reaction, which brought a limitation of whiteness.

Comparative Example 4

In the same manner as in Example 1, 60 parts by weight of the small-diameter rubber latex prepared in the small-diameter rubber latex manufacturing process instead of 60 parts by weight of the large-diameter rubber latex used in the graft ABS copolymer process was compared.

The physical property results compared are shown in Table 1.

As a result of the physical property comparison, the particle size of the rubber latex is small, which brings a limit of impact strength.

Comparative Example 5

Perform the same method as in Example 1 except that the amount of acetic acid used for fusion in the large-diameter rubber latex manufacturing process by fusion using 4.0 parts by weight instead of 3.0 parts by weight to produce an ultra large diameter rubber latex having a particle diameter of 4500 하고 and Instead of 60 parts by weight of the large diameter rubber latex used in the manufacture of the graft ABS copolymer, 60 parts by weight of the ultra large diameter rubber latex thus obtained was compared. The graft rate was 20%.

The physical property results compared are shown in Table 1.

As a result of the physical property comparison, gloss was decreased due to the low graft ratio.

Comparative Example 6

In the same manner as in Example 1 except that 0.6 parts by weight instead of 0.3 parts by weight of the third grade dodecyl mercaptan used in the small-diameter rubber latex process was compared by reacting for 13 hours instead of 10 hours .

The particle size of the obtained rubber latex was 1050 Pa, and the gel content was 68.

These were fused with acetic acid in the same manner as in Example 1 to prepare large-diameter rubber latex and used to prepare ABS graft copolymer.

The physical property results compared are shown in Table 1.

As a result of the physical property comparison, the low gel content brought the limit of gloss.

Comparative Example 7

In the same manner as in Example 1 except that 0.1 parts by weight instead of 0.3 parts by weight of tertiary dodecyl mercaptan, which is used first in the small-diameter rubber latex process, and the reaction time was compared by reacting for 9 hours instead of 10 hours .

The particle size of the obtained small-diameter rubber latex was 950 Pa and the gel content was 96.

These were fused with acetic acid in the same manner as in Example 1 to prepare large-diameter rubber latex and used to prepare ABS graft copolymer.

The physical property results compared are shown in Table 1.

As a result of the physical property comparison, the impact strength was lowered due to the high gel content.

Comparative Example 8

The ABS graft copolymer to be used in the same manner as in Example 1, but the ABS graft copolymer is not prepared by the emulsion polymerization was compared using the ABS graft copolymer prepared by the bulk polymerization method.

At this time, due to the viscosity problem, a rubber graft copolymer having a rubber content of 13% by weight was prepared, and was used as it is without kneading with general SAN.

The physical property results compared are shown in Table 1.

As a result of the physical property comparison, the use of ABS graft copolymer prepared by the bulk polymerization method brought a limit of gloss and impact strength.

division Notched Izod Impact Strength (ASTM D256) Glossiness (45 °) Whiteness Fluidity (ASTM D1238) Example 1 38 100 55 22 Comparative Example 1 40 85 60 18 Comparative Example 2 37 101 46 23 Comparative Example 3 39 100 50 22 Comparative Example 4 12 103 56 20 Comparative Example 5 43 80 53 16 Comparative Example 6 41 93 54 23 Comparative Example 7 32 101 56 22 Comparative Example 8 24 70 62 25

ABS-based thermoplastic resin produced by the method of the present invention is excellent in impact resistance, chemical resistance, molding processability, etc., but also excellent in glossiness and whiteness.

Claims (5)

In the manufacturing method of the ABS-based thermoplastic resin comprising the step of kneading the acrylonitrile-butadiene-styrene graft copolymer prepared by emulsion polymerization and the styrene-acrylonitrile copolymer prepared by bulk polymerization, The acrylonitrile-butadiene-styrene graft copolymer a) first graft polymerization of 11 to 25 parts by weight of aromatic vinyl compound and 3 to 16 parts by weight of vinyl cyan compound in a continuous or divided dose to 45 to 75 parts by weight of large-diameter rubber latex; And b) performing secondary graft polymerization by continuously or separately adding 6-15 parts by weight of aromatic vinyl compound and 1-4 parts by weight of vinylcyan compound to the first graft polymer; Method for producing an ABS-based thermoplastic resin produced by a method comprising a. The method of claim 1, The large-diameter rubber latex of step a) has a particle size of 2500 to 4000 mm 3, a gel content of 70 to 95, and a swelling index of 12 to 30. The method of claim 1, The large diameter rubber latex of step a) is an aliphatic conjugated diene compound or a mixture of an aliphatic conjugated diene compound and an ethylenically unsaturated compound. The method of claim 1, ABS system wherein the aromatic aromatic vinyl compounds of steps a) and b) are selected from the group consisting of styrene, α-methylstyrene, ο-ethylstyrene, Ρ-ethylstyrene, vinyltoluene, and derivatives thereof Method for producing a thermoplastic resin. The method of claim 1, The vinyl cyan compound of step a) and step b) is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, ethacrylonitrile, and derivatives thereof.