KR100236773B1 - Process for the preparation of aromatic vinyl-vinyl cyanide copolymer resin - Google Patents

Abstract

(A) 65 to 90 parts by weight of an aromatic vinyl compound mainly composed of α-methylstyrene, 10 to 35 parts by weight of a vinyl cyanide compound, 5 to 10 parts by weight of other copolymerizable monomers, and 0.1 to 1.0 weight of a molecular weight regulator in ion-exchanged water And one or more reducing agents selected from the group consisting of reaction initiators, emulsifiers and sodium salts of ascorbic acid, sodium salts of formaldehyde, dextrose sodium salts, sodium salts of ethylene diamine tetraacetic acid, sodium pyrophosphate salts and ferrous sulfate Reacting for 30 minutes to 2 hours at 40 to 70 ° C. by adding an oxidation-reduction catalyst including at least one oxidant selected from the group consisting of cumene hydroperoxide, diisopropyl benzene hydroperoxide and tertiary butyl hydroperoxide Step, and (b) 10 to 20 weight of vinyl cyanide compound to the reaction product of step (a) According to the method for producing an aromatic vinyl compound-vinyl cyanide compound copolymer resin comprising the step of continuously adding and reacting a mixture of 0 to 1.0 parts by weight of the molecular weight regulator and the oxidation-reduction catalyst, the heat distortion temperature is high and heat resistance In addition to producing excellent resins, polymerization is carried out at low temperatures using highly active oxidation-reduction catalysts to minimize unreacted monomers, simplifying the manufacturing process, improving latex stability, and reducing reaction times, resulting in increased reaction productivity. Is increased.

Description

Production method of aromatic vinyl compound-vinyl cyanide compound copolymer resin {PROCESS FOR THE PREPARATION OF AROMATIC VINYL-VINYL CYANIDE COPOLYMER RESIN}

The present invention relates to a method for producing a thermoplastic resin having excellent heat resistance, and more particularly, to an aromatic vinyl compound-vinyl having excellent latex stability and thermal stability under high polymerization conversion by two-step emulsion polymerization of an aromatic vinyl compound and a vinyl cyanide compound monomer. A method for producing a cyanide compound copolymer resin.

Generally, ABS resin (acrylonitrile-butadiene-styrene copolymer) is widely used in parts of automobiles, electronics and office equipment because it has excellent balance of physical properties such as impact resistance, mechanical strength, molding processability and surface gloss. In recent years, as the demand for improving the heat resistance of plastics used in parts such as automobiles, electronic devices, office automation devices, and home appliances has rapidly increased, efforts have been made to develop heat-resistant resins having higher heat deformation temperatures. have.

Conventionally, one method that has been generally used to increase the heat deformation temperature of ABS resin is a method of blending with polycarbonate, which increases the polycarbonate content to increase the heat deformation temperature to 120 ° C. Since it should be maintained at about 50 to 60%, there is a disadvantage that the manufacturing cost is increased and cannot be used. There is another method of filling the inorganic material, but this method can increase the heat deformation temperature to 99 to 116 ℃ by filling the inorganic filler with 20 to 40% of the total resin, but the heat resistance is small compared to the filling amount and impact resistance There is a disadvantage of deterioration. Recently, a method of copolymerizing N-phenylmaleimide with styrene has been used to improve heat resistance. However, this method requires that at least 30% of expensive N-phenylmaleimide be added to prepare a resin having a heat distortion temperature of 125 ° C. or higher. Therefore, it is difficult to put practical use due to the rising cost. In addition, styrene and α-methylstyrene may be copolymerized to prepare a resin having a heat deformation temperature of 104 to 116 ° C. However, when the content of α-methylstyrene is increased, the heat deformation temperature is increased, but moldability is decreased and α-methyl is increased. Since styrene is a low reactive monomer, a complicated process is required to remove unreacted α-methylstyrene.

Accordingly, the present inventors have conducted studies to improve the moldability of the aromatic vinyl compound-vinyl cyanide compound copolymer and to increase the reactivity of the low-reacting monomer, α-methylstyrene, resulting in the emulsion polymerization by dividing the copolymer into two stages. The above object can be achieved, and in the second step, the polymerization is carried out at a low temperature by using an oxidation-reduction catalyst having excellent activity.

Accordingly, an object of the present invention is to provide a method for producing a thermoplastic resin having excellent heat deformation temperature, latex stability, and the like under high polymerization conversion.

In order to achieve the above object, in the present invention, (a) 65 to 90 parts by weight of an aromatic vinyl compound mainly composed of α-methylstyrene, 10 to 35 parts by weight of a vinyl cyanide compound, and other copolymerizable monomers 5 to ion-exchanged water 10 parts by weight, molecular weight regulator 0.1 to 1.0 part by weight, reaction initiator, emulsifier and sodium salt of ascorbic acid, sodium salt of formaldehyde, dextrose sodium salt, sodium salt of ethylene diamine tetraacetic acid, sodium pyrophosphate salt and sulfuric acid 40 to 70 by adding an oxidation-reduction catalyst comprising at least one reducing agent selected from the group consisting of ferrous iron and at least one oxidant selected from the group consisting of cumenehydro peroxide, diisopropyl benzene hydroperoxide and tertiary butyl hydroperoxide Reaction at 30 ° C. for 2 minutes to 2 hours, and (b) reaction of step (a) 10 to 20 parts by weight of a vinyl cyanide compound, 0 to 1.0 parts by weight of a molecular weight modifier, and a mixture of the redox catalyst and a mixture of the aromatic vinyl compound and vinyl cyanide compound It provides a manufacturing method.

Copolymer resin prepared according to the method of the present invention can be used in combination with the following heat-resistant copolymer (I) and graft copolymer (II) to obtain a resin composition excellent in moldability and impact resistance:

Copolymer (I): a copolymer comprising 73% by weight of a styrene monomer and 27% by weight of an acrylonitrile monomer;

Graft copolymer (II): The copolymer which grafted 43 weight% of styrene monomer and 17 weight% of acrylonitrile monomer to 40 weight% of rubber | gum.

Hereinafter, the present invention will be described in detail.

The aromatic vinyl compound used in the present invention includes α-methyl styrene, methyl styrene, m-methyl styrene, p-methyl styrene, dimethyl styrene, and the like, and α-methyl styrene is particularly preferable, and the vinyl cyanide compound is acryl. Unsaturated nitriles such as ronitrile, methacrylonitrile, methylmethacrylonitrile can be used. Other copolymerizable monomers may include acrylates such as methyl methacrylate and methyl acrylate.

As the emulsifier, anionic surfactants such as sodium salts and potassium salts of rosin acid and higher fatty acids, sodium salts and potassium salts of alkylsulfonic acid, and the like can be used alone or in combination of two or more thereof.

Polymerization catalysts are of great importance and it is suitable to use redox catalysts. The redox catalyst includes a reducing agent consisting of sodium salt of ascorbic acid, sodium salt of formaldehyde, sodium dextrose salt, sodium salt of ethylene diamine tetraacetic acid, sodium pyrophosphate salt and ferrous sulfate. And cumene hydroperoxide, diisopropyl benzene hydroperoxide and tertiary butyl hydroperoxide. Of these catalysts, ascorbate-based oxidation-reduction catalysts are preferred because they allow polymerization to be carried out in a low temperature range. The amount of reducing agents in the catalysts is based on the total amount of monomers, 0.01 to 5% by weight of sodium ascorbate or sodium of formaldehyde, 0 to 0.8% by weight of sodium salt of ethylene diamine tetraacetic acid, and ferrous sulfate It is preferable that it is 0 to 0.1 weight%. In the oxidation-reduction catalyst, as the oxidizing agent, cumene hydroperoxide, diisopropyl benzenehydro peroxide, t-butylhydroperoxide, etc. are preferable, and the amount of the oxidizing agent is 0.3 to 5% by weight based on the total amount of monomers. As the chain transfer agent, n-dodecyl mercaptan or tertiary dodecyl mercaptan can be used.

The polymerization reaction temperature is more preferably 65 ° C. or less in order to minimize the amount of latex and increase the amount of unreacted α-methylstyrene as the temperature increases.

The copolymer latex produced as described above is coagulated with calcium chloride, the copolymer is recovered, washed with water and dried. The powder thus obtained is dried and then kneaded with copolymer resin (I) or graft copolymer (II), followed by injection molding to prepare specimens to measure physical properties such as impact strength, fluidity, and heat deformation temperature.

Hereinafter, the present invention will be described in more detail based on Examples. However, these Examples are only for illustrating the present invention, the present invention is not limited to these. In the examples, "parts" and "%" refer to "parts by weight" and "% by weight", respectively.

Example 1

In a reactor substituted with nitrogen, a one-step component of the copolymer shown in Table 1 was added and emulsified with stirring under a nitrogen atmosphere. When the temperature inside the reactor reached 45 ° C, a solution of 0.01 part by weight of ferrous sulfate and 0.3 part by weight of ethylene diamine tetraacetic acid tetrasodium salt dissolved in 25 parts by weight of ion-exchanged water was added to the reactor, followed by 0.3 part by weight of cumene hydroperoxide. The polymerization was initiated by the addition. After the reaction was continued while the reactor internal temperature was raised to 58 ° C. for 1 hour, the second stage components of the copolymer of Table 1 were continuously added for 3 hours or more while maintaining the reactor internal temperature at 58 ° C. After the dosing was complete, the three stage components of the copolymer were administered and the reaction continued at the same temperature for 1 hour. Subsequently, the fourth stage component of the copolymer was administered and reacted for 1 hour to obtain a copolymer resin. The polymerization conversion rate at this time was found to be 96% or more. An antioxidant was added to the latex thus obtained, coagulated with a salt, washed and dried to obtain a white powder. Copolymer (I) comprising 73% by weight of styrene monomer and 27% by weight of acrylonitrile monomer and 43% by weight of styrene monomer and 17% by weight of acrylonitrile monomer in this powder (II). ) Was mixed and extruded and extruded at 230 ° C. to prepare specimens and the solid coagulum content, impact strength, flowability and heat deflection temperature were measured and the results are shown in Tables 3 and 4.

Stage 1 Ion exchange water 390 Sodium dodecyl sulfonate 6.0 Sodium ascorbate 0.8 α-methylstyrene 190 Styrene 2.5 Acrylonitrile 15 Class 3 dodecyl mercaptan 1.3 2 step Ion exchange water 200 Sodium dodecyl sulfonate 3.0 Acrylonitrile 35 Methacrylonitrile 2.5 Methyl methacrylate 2.5 Class 3 dodecyl mercaptan 0.3 Cumene Hydroperoxide 0.4 3 steps Ion exchange water 43 Sodium dodecyl sulfonate 0.3 Sodium ascorbate 0.3 Styrene 2.5 Ethylenediaminetetraacetic acid tetrasodium salt 0.13 Ferrous sulfate 0.005 Cumene Hydroperoxide 0.15 4 step Ion exchange water 23 Sodium ascorbate 0.15 Ethylenediaminetetraacetic acid tetrasodium salt 0.08 Ferrous sulfate 0.003 Cumene Hydroperoxide 0.08

Example 2

The copolymer was obtained in the same manner as in Example 1 except that the reducing agents ferrous sulfate and ethylene diamine tetraacetate tetrasodium salt were not used in the redox catalyst used in each step of Example 1 to obtain a copolymer. The results are shown in Table 4 below.

Example 3

Except for maintaining the reaction temperature at 58 ℃ in step 2 was carried out in the same manner as in Example 1 except that the temperature was increased from 58 ℃ to 70 ℃ to obtain a copolymer and the results are shown in Table 4.

Comparative Example 1

In a reactor substituted with nitrogen, a one-step component of the copolymer shown in Table 2 was added thereto, followed by emulsification with stirring under a nitrogen atmosphere. When the temperature inside the reactor reached 40 ° C, a solution of 0.0073 parts by weight of ferrous sulfate and 0.24 parts by weight of ethylene diamine tetraacetic acid tetrasodium salt dissolved in 36 parts by weight of ion-exchanged water was added to the reactor, followed by diisopropylbenzenehydroperoxide. 0.4 weight part was added and polymerization was started. After the reaction was continued while the reactor internal temperature was raised to 58 ° C. for 1 hour, the second stage components of the copolymers of Table 2 were continuously added for 4 hours while maintaining the reactor internal temperature at 58 ° C. After the dosing was complete, the third stage components of the copolymers of Table 2 were administered and the reaction continued at the same temperature for 1 hour. Subsequently, the fourth stage component of the copolymer was administered and reacted for 1 hour to obtain a copolymer resin. At this time, the polymerization conversion was found to be 96% or more, and the solid coagulum content was 0.3%. An antioxidant was added to the latex thus obtained, coagulated with a salt, washed and dried to obtain a white powder. 5 parts by weight of the same copolymer (I) and 45 parts by weight of the graft copolymer (II) were mixed with the powder and extruded and injected at 230 ° C. to prepare a specimen, and a solid coagulant content and impact strength were used. , Flowability and heat deflection temperature were measured and the results are shown in Table 3.

Stage 1 Ion exchange water 474 Sodium dodecyl sulfonate 3.6 α-methylstyrene 190 Styrene 2.5 Acrylonitrile 12 Class 3 dodecyl mercaptan 0.8 2 step Ion exchange water 132 Sodium dodecyl sulfonate 0.51 Methyl methacrylate 2.0 Class 3 dodecyl mercaptan 0.3 Diisopropyl benzenehydro peroxide 0.4 3 steps Ion exchange water 6 Sodium dodecyl sulfonate 0.51 Acrylonitrile 2.5 Ethylenediaminetetraacetic acid tetrasodium salt 0.04 Ferrous sulfate 0.0012 Diisopropyl benzenehydro peroxide 0.12 4 step Ion exchange water 35 Dodelyl Sodium Sulfonate 0.14 Acrylonitrile 9.1 Ethylenediaminetetraacetic acid tetrasodium salt 0.04 Ferrous sulfate 0.0012 Diisopropyl benzenehydro peroxide 0.012

Unit: parts by weight

Comparative Example 2

Except for using sodium formaldehyde sulfoxylate salt instead of sodium ascorbate in the same manner as in Example 1 to obtain a copolymer and the results were shown in Table 4.

Comparative Example 3

Except for using ascorbic acid instead of sodium ascorbate was carried out in the same manner as in Example 1 to obtain a copolymer and the results are shown in Table 4.

Example 1 Comparative Example 1 Copolymer (I) 5 parts by weight 5 parts by weight Graft Copolymer (II) 45 parts by weight 45 parts by weight Izod impact strength (kgkg / cm) (notched, 1/4 ") ASTM D256 18 18 Fluidity (g / 10min) (220 ℃, 10kg) ASTM D1238 7 5 Heat Deflection Temperature (℃) (Unannealed, 18.5kg / cm ² , 1/2 ") ASTM D648 100 98

Example 1 Example 2 Example 3 Comparative Example 2 Comparative Example 3 Polymerization Conversion Rate (%) 97 96 97 88 90 Solidified solids (%) 0 0.1 0.3 1 or more 1 or more

As can be seen from the above results, it can be seen that the thermoplastic resin prepared according to the present invention exhibits a high polymerization conversion and is excellent in balance in impact strength, fluidity and heat deformation temperature.

As described above, the reaction mixture, an oxidation-reduction catalyst, and an emulsifier are added to the monomer mixture of the aromatic vinyl compound, the vinyl cyanide compound, and other copolymerizable monomers and the molecular weight modifier, and then the vinyl cyanide compound, the molecular weight modifier, and the oxidation-reduction catalyst are reacted. According to the method of the present invention by mixing and adding two-step emulsion polymerization, not only a resin having a high heat deformation temperature and excellent heat resistance is produced, but also an unreacted monomer by polymerization at a low temperature using an oxidation-reduction catalyst having excellent activity. By minimizing the production process is simple, the latex stability is improved and the reaction time is shortened to increase the reaction productivity.

Claims (3)

(A) 65 to 90 parts by weight of an aromatic vinyl compound mainly composed of α-methylstyrene, 10 to 35 parts by weight of a vinyl cyanide compound, 5 to 10 parts by weight of other copolymerizable monomers, and 0.1 to 1.0 weight of a molecular weight regulator in ion-exchanged water And one or more reducing agents selected from the group consisting of reaction initiators, emulsifiers and sodium salts of ascorbic acid, sodium salts of formaldehyde, sodium dextrose sodium salts, sodium salts of ethylenediamine tetraacetic acid, sodium pyrophosphate salts and ferrous sulfate Reacting for 30 minutes to 2 hours at 40 to 70 ° C. by adding an oxidation-reduction catalyst including at least one oxidant selected from the group consisting of cumene hydroperoxide, diisopropyl benzene hydroperoxide and tertiary butyl hydroperoxide Steps, and (B) 10 to 20 parts by weight of the vinyl cyanide compound, 0 to 1.0 parts by weight of the molecular weight regulator and the redox catalyst mixed with the reaction product of step (a) by continuously adding Method for producing an aromatic vinyl compound-vinyl cyanide compound copolymer resin comprising a. The method of claim 1, Wherein said catalyst comprises from 0.01 to 5% by weight sodium ascorbate salt. In the copolymer prepared by the method of claim 1, a copolymer comprising 73% by weight of styrene monomer and 27% by weight of acrylonitrile monomer, and 43% by weight of styrene monomer and 17% by weight of acrylonitrile monomer in 40% by weight of rubber. A thermoplastic resin prepared by mixing the grafted copolymer.