KR0142629B1 - Thermoplaslic resin composifion - Google Patents

Abstract

The present invention relates to a method for producing a novel graft polymer for a thermoplastic resin composition having excellent impact resistance and elongation characteristics, and includes a graft in which a rubber having an average particle diameter of 0.25-0.40 µm and a rubber of 0.50-1.0 µm are mixed together. In preparing the copolymer, 30 to 60 parts by weight of the total butadiene rubbery polymer latex and 70 to 40 parts by weight of the monomer mixture are characterized in that the two-step reaction.

Description

Method for producing a thermoplastic resin composition excellent in impact resistance and elongation characteristics

The present invention relates to a method for producing a novel graft polymer for a thermoplastic resin composition having excellent impact resistance and elongation characteristics. More particularly, the present invention relates to a graft copolymer containing two or more rubbery polymers having different particle diameters. A method for producing a novel graft polymer of a thermoplastic resin composition having high elongation characteristics.

Acrylonitrile-butadiene-based rubber-styrene copolymer (hereinafter referred to as ABS resin) Resin is produced by bulk polymerization, suspension polymerization, block-suspension polymerization, emulsion polymerization, etc., but is produced by other polymerization method except emulsion polymerization. Resin has many disadvantages in polymerization rate and polymerization operation compared with emulsion polymerization method, and it is difficult to produce resin with high rubber content.

In general, a resin composition having high impact resistance and high elongation can be prepared by graft polymerization of a monomer such as styrene acrylonitrile in the presence of butadiene-based rubber latex. In this case, the particle diameter and particle size distribution of the rubber and emulsion polymerization method The graft copolymerization method in Essence greatly influences the mechanical strength and appearance of the resin surface such as impact resistance of the final product. Therefore, in the impact resistant resin such as ABS resin, it is known that the larger the particle size of the rubber, the better the physical properties such as impact resistance and workability, but when the particle diameter of the rubber latex becomes larger than necessary, a large amount of coagulum is generated during the graft polymerization. In practice, there are many difficulties, but rather physical properties such as impact strength are lowered.

Thus, in order to prepare a thermoplastic resin composition having excellent physical properties such as impact strength and high elongation, a particle diameter of rubbery polymer latex is mixed with a large particle diameter and a medium particle diameter and then graft polymerized to coagulate the solids generated during the graft polymerization. Methods to improve the physical properties such as impact resistance and elongation while suppressing as much as possible are known. However, the graft copolymer obtained by graft polymerization of a rubber having a large particle diameter and a rubber of a small particle size before the graft polymerization has been developed. Was not satisfactorily satisfied, and in particular, there are many unplasticized particles (SANDSURFACD, PINHOLE) on the resin surface, which has a disadvantage in that the product value of the final molded product is lowered.

In addition, a method of graft polymerizing a large-diameter rubber and a small-size rubber, respectively, to mix graft latexes or to mix powders obtained through a solidification and drying process are known. However, the graft reaction performed in the presence of rubber latex having a particle diameter of 0.50 µm or more in such a mixing method is not practical due to deterioration of the mechanical stability of the emulsion during polymerization, and the coagulum is not practical in the final resin composition. The particles are mixed and the plasticized appearance of the molded article such as an extrusion sheet (SHEET) is unplasticized. Therefore, in order to suppress the formation of coagulants, the amount of emulsifier, etc. is greatly increased. However, the improvement of the amount of coagulant is produced. It is not desirable to rise.

An object of the present invention is to provide a thermoplastic resin composition having an excellent impact resistance and high elongation while improving the graft manufacturing method by an emulsion polymerization method having industrial advantages while compensating for such disadvantages.

The present inventors have diligently studied to achieve the above object, and as a result of preparing graft polymers in which rubber having an average particle diameter of rubber latex of 0.25-0.40 µm and rubber having an average particle diameter of 0.50-1.0 µm are mixed, In consideration of the surface area per unit volume of rubber particle diameter, it has a suitable graft ratio. First, a rubber latex having a particle diameter of 0.25-0.40㎛ is present in the graft polymerization system and a part of the entire graft monomer mixture is added to polymerize to an appropriate conversion rate. Graft by a first step of preparing a first graft latex, and adding a rubber having a particle diameter of about 0.50-1.0 μm in the presence of the first graft latex, and then continuously adding the remaining graft monomer mixture. The reaction is uniform when combined in a two-step reaction to complete the wort reaction to produce a second graft latex. It has been found that it is possible to minimize the coagulum generated during the reaction during the reaction, and to obtain a thermoplastic resin composition having excellent physical properties such as impact strength and elongation properties due to the uniform graft reaction on the large and small rubber particles. .

Hereinafter, the present invention will be described in detail.

The rubbery polymer which can be used in the present invention contains 70% by weight or more of butadiene such as copolymers of aromatic vinyl compounds such as polybutadiene, butadiene-styrene, alphamethylstyrene, copolymers of acrylic compounds such as butadiene-acrylic acid and methacrylic acid And latex containing copolymers of butadiene and other copolymerizable monomers.

The average rubber particle diameter of these rubbery polymer latexes is preferably about 0.25-0.40 µm for the primary graft reaction, and preferably about 0.50-1.0 µm for the secondary graft reaction. Particularly, the rubber of 0.50-1.0㎛ large particle size used in the secondary graft reaction can be prepared by adjusting the particle size and the particle size distribution in advance or by coagulating the small particle size rubber of 0.03-0.10㎛ (e.g. Agglomerated rubber, agglomerated by shear force, agglomerated by electrolyte, agglomerated by cold freezing, etc.). The rubber latex with the particle size and the particle size of 0.5-1.0㎛ is distributed at the same time but the distribution ratio of 0.1-0.18㎛ particle: 0.5-1.0㎛ particle is about 5-30: 95-70%.

The graft copolymer production method in the presence of two kinds of rubbery polymer latex satisfying the above properties is as follows.

1) Preparation of Primary Graft Latex

In the presence of butadiene-based rubber latex having an average particle diameter of 0.25-0.40 µm, a part of one or two or more monomer mixtures selected from aromatic vinyl monomers and unsaturated nitrile monomers as graft monomers, emulsifiers, polymerization initiators, molecular weight regulators, and ion exchanges The solution was added by dividing the water and stirred, and the temperature was raised to 50-65 ° C., and when the mixture temperature reached 50-65 ° C., the stirring was continued for 10 minutes to 1 hour 30 minutes, and the monomers were mostly introduced into the rubber particles. Swelling is followed by addition of a redox composition to polymerize the first-grafted graft monomer in the range of 60-75 ° C. to produce a primary graft latex with a conversion of at least 90%.

2) Preparation of Secondary Graft Latex

In the presence of the prepared primary graft latex, butadiene-based rubbery latex having an average particle diameter of 0.50-1.0 μm was added at a time to bring the reactor internal temperature to 50-70 ° C., followed by the remaining graft monomer mixture and molecular weight. Continuous addition of the first input residue of the regulator and polymerization initiator over 1 to 5 hours, at which time the reaction temperature is in the range of 50-75 ℃, the final polymerization conversion of 90-98%, solid content of 38-44% secondary graph It is prepared by a two-step graft reaction to prepare the latex.

The graft polymer latex was coagulated with isopropyl alcohol to obtain a white powder, which was dissolved in acetone, centrifuged, and the insolubles were washed, dried, and measured after grafting.

The graft rate formula is as follows.

In order to meet the purpose of the present invention, the graft rate must be 45-70% by weight. If the graft ratio is lower than this, it is difficult to recover the powder having a uniform particle size distribution during solidification and drying, and unplasticized particles appear on the surface of the molded product during extrusion injection, which lowers the surface glossiness. May result.

The monomers usable in the present invention include styrene, alpha methyl styrene, alpha chloro styrene, copolymerizable with 30 to 60 parts by weight of the total butadiene rubber polymer latex (the solid content of the total butadiene rubber latex and the monomer mixture is 100 parts by weight). Aromatic vinyl monomers such as divinylbenzene and unsaturated nitrile monomers such as acrylonitrile and methacrylonitrile are preferable. Among them, 70-40 parts by weight of a styrene and acrylonitrile monomer mixture (the styrene and acrylonitrile monomer composition ratio is 70:30) is preferable.

In more detail, the styrene and acrylonitrile monomer mixtures were first made into 10-40% of the total monomer mixture 100 in the presence of 60-95% by weight of the rubbery latex in a rubber having an average particle diameter of 0.25-0.40 µm. In the presence of the prepared graft latex, the remaining amount of rubber (40-5% by weight) having an average particle diameter of 0.50-1.0 µm was added thereto, and the remaining amount of styrene and acrylonitrile monomer mixture was 90-60. It is good to copolymerize by the method of continuously adding%.

When the content of the total rubbery latex is less than the above range, the impact resistance of the resin is lowered, and when used in excess, it is difficult to sufficiently increase the graft rate of the graft polymer, and it is difficult to recover the fine powder during solidification and drying. And appearance deteriorate. On the other hand, when the amount of the large-diameter rubber is used in the range of 0.25-0.40㎛ medium-diameter rubber and 0.50-1.0㎛ large-diameter rubber is smaller than the above range, it is difficult to expect the desired properties such as high elongation and impact resistance. When used, a large amount of coagulum is generated due to deterioration of the safety during polymerization, and thus unplasticized particles appear on the surface of the molded article, resulting in deterioration in appearance and deterioration in glossiness, but rather in physical properties such as impact strength.

Among the monomers used in the graft reaction, the monomer used in the first graft reaction swells the rubber latex particles so that more monomers are polymerized in the rubber, thereby affecting properties such as impact strength and continuously injected graft. The graft reaction proceeds uniformly around the rubber, and after half, the rubber structure maintains the equilibrium state between the inside and the outside of the rubber particles by the graft monomers, thereby obtaining the desired physical properties of the monomer. When the ratio of the input ratio is out of the above range, the composition and amount of the graft monomer inside and outside the rubber are not appropriate, and thus the object of the present invention cannot be achieved.

In addition, the reaction temperature should also be controlled during the graft polymerization. If the polymerization temperature is lower than the above range during the first and second graft reactions, the polymerization rate becomes slow, which is undesirable. There is a problem that water is likely to occur. In addition, the type and amount of the emulsifier, the molecular weight regulator, and the polymerization initiator and the addition rate thereof are also very important.

As the emulsifier usable in the present invention, those used in a conventional emulsion polymerization method may be used, and examples thereof include fatty acid metals such as sodium laurate, sodium oleate, and potassium oleate, sodium lauryl sulfate, sodium naphthalene sulfonate, and the like. And alkali methsulfonate of allyl sulfonic acid such as sodium isopropyl naphthalene sulfonate, potassium rosinate and the like. Preferably, one or two or more mixed emulsifiers selected from potassium oleate, sodium lauryl sulfate, and calcium rosinate are preferable. The amount of these used is preferably 0.4-2.5 parts by weight, and when used in a smaller amount than the above range, a large amount of coagulant is generated in latex, which is not preferable, and when used in excess, it is difficult to control physical properties such as graft rate of graft polymer due to excessive generation of non-graft polymer. In addition, in injection molding, the appearance of the molded article may be deteriorated due to gas generation or the like.

As the molecular weight regulator which can be used in the present invention, it is preferable to use a molecular weight regulator such as a mercaptan having 8 to 18 carbon atoms or an organic activator compound, and the amount of these used amount is 0.05-0.35 parts by weight for the first graft reaction and the second graft. 0-0.35 parts by weight is preferred for the reaction. As the polymerization initiator, fat-soluble initiators such as cumene hydroperoxide, benzoyl peroxide, and cumyl peroxide, and water-soluble initiators such as ammonium persulfate, potassium persulfate, and potassium carbonate can be used, but cumene hydroperoxide and benzoyl are preferred. One or two or more polymerization initiators selected from peroxide and potassium persulfate are preferred.

The amount of these used is 0.10-0.25 parts by weight for the first graft reaction, 0.10-0.45 parts by weight for the second graft reaction, and the molecular weight modifier and polymerization initiator used in the second graft reaction are uniform graft polymerization and molecular weight. And it is preferable to continuously inject over 1 hour to 5 hours in order to induce a molecular weight distribution uniformly.

The graft latex prepared above was solidified with 0.5-1.5% sulfuric acid aqueous solution and dried to obtain a white powder, and then separately adjusted after adjusting the content of a separately produced styrene-acrylonitrile copolymer (hereinafter referred to as SAN resin). And through the injection process it can be produced ABS resin excellent in impact resistance and elongation.

Embodiments of the present invention are as follows.

Example 1

1) preparing the first graft copolymer latex

45.0 parts of butadiene rubbery latex (hereinafter referred to as `` latex-1 '') having a stirrer, a heating device, a cooling device, a condenser, a continuous input device of monomers and a polymerization initiator, and an average particle diameter of 0.30 µm and a gel content of 76% by weight. The following parts are by weight), 140 parts of ion-exchanged water, 1.0 part of potassium rosinate, 0.30 part of dextrose and then stirred into 4.5 parts of acrylonitrile, 10.5 parts of styrene, 0.15 parts of tertiary dodecyl mercaptan and cumene After 0.13 parts of hydroperoxide was added, stirring was continued for 40 minutes, and then 0.05 parts of ferrous sulfate and 0.20 parts of tetrasodium parophosphate were added. The reaction was initiated to 70 ° C. and reached 70 ° C. for 20 minutes. After the polymerization was continued and the polymerization conversion rate reached 93% or more, the reaction was terminated to prepare a first graft latex.

2) Preparation of Secondary Graft Copolymer Latex

5.0 parts of butadiene rubber latex (hereinafter referred to as Latex-2: KSL-341 manufactured by Kumho Petrochemical Co., Ltd.) having an average particle diameter of 0.60 µm and a gel content of 35% by weight in the presence of the prepared primary graft latex. Into the reactor, the temperature was brought to 65 ° C. and stirred for 20 minutes, followed by 24.5 parts of styrene, 10.5 parts of acrylonitrile, and 0.15 parts of tertiary dodecyl mercaptan in a stirred container, followed by stirring for 10 minutes, followed by continuous feeding for 3 hours. At the same time, 0.30 part of cumene hydroperoxide was continuously added over 3 hours to proceed with the secondary graft reaction. When the monomer and polymerization initiator are added, the reaction is continued for 40 minutes and the reaction is terminated. At this time, the reaction temperature was gradually proceeded to start the second graft reaction at 65 ℃ to reach 75 ℃, the content of the total rubber polymer was 50 parts by solid content, the conversion rate after the completion of the polymerization was 98%, the solid content of the latex obtained was 40.9%. .

* Measurement of produced coagulum

After the completion of the first and second graft polymerization reaction, the graft latex was filtered through a 200 mesh (MESH) wire mesh, and the coagulum which did not pass through the mesh was dried at 100 ° C. for 12 hours, and then weighed.

The coagulum after the reaction of Example 1 was 0.15%. In all the following Examples and Comparative Examples, the coagulum was measured by the method of Example 1.

40 parts of the powder obtained by the solidification and drying process, 40 parts of SAN-1 (weight average molecular weight 180,000) and 20 parts of SAN-2 (weight average molecular weight 120,000) are mixed with a stabilizer and a lubricant, followed by injection molding. A test piece for measuring the physical properties was prepared to measure the overall physical properties.

Example 2

Same as Example 1 except that 42.5 parts of latex-1 was used for the first graft reaction and 7.5 parts of latex-2 were used for the second graft reaction.

Example 3

Same as Example 1 except for using 40 parts of latex-1 for the first graft reaction and 10 parts for latex-2 for the second graft reaction.

Example 4

Same as Example 1 except that 35 parts of latex-1 was used for the first graft reaction and 15 parts of latex-2 were used for the second graft reaction.

Example 5

Same as Example 1 except that 30 parts of latex-1 was used for the first graft reaction and 20 parts of latex-2 were used for the second graft reaction.

Comparative Example 1

50 parts of latex-1 (based on solids), 140 parts of ion-exchanged water, 1.0 part of potassium rosinate, and 0.3 part of dextrose were added to the reactor, followed by stirring. 4.5 parts of acrylonitrile, 10.5 parts of styrene, tertiary dodecyl mercaptan 0.13 parts, 0.15 parts of cumene hydroperoxide was added thereto, and the temperature was raised to 60 ° C. When the temperature of the mixture reached 60 ° C, 0.05 part of ferrous sulfate and 0.2 part of tetrasodium parophosphate were added to proceed with polymerization for 1 hour. After completion of the first graft polymerization, 24.5 parts of styrene, 10.5 parts of acrylonitrile and 0.15 parts of tertiarydecyl mercaptan at 70 ° C. were added to a stirred container, stirred for 10 minutes, and continuously added for 3 hours, followed by 0.30 cumene hydroperoxide. Part was continuously added over 3 hours to proceed with the secondary graft reaction. When the monomer and polymerization initiator are added, the reaction is continued for 40 minutes and the reaction is terminated. At this time, the reaction temperature was slowly progressed to start the second graft reaction at 70 ℃ to reach 75 ℃, after the polymerization was evaluated in the same manner as in Example 1.

Comparative Example 2

Same as Comparative Example 1 except 50 parts of Latex-2 were used.

Comparative Example 3

Same as Comparative Example 1 except that 42.5 parts of Latex-1 and 7.5 parts of Latex-2 (50 parts of total rubber content based on solids) were premixed before the graft reaction.

Comparative Example 4

Same as Comparative Example 1 except that 35.0 parts of Latex-1 and 15.0 parts of Latex-2 (50 parts of total rubber content) were mixed before use for the graft reaction.

Comparative Example 5

The graft polymer of Comparative Example 1 and the graft polymer of Comparative Example 2 were latex mixed at 15:85, and then solidified and dried to evaluate various properties.

Quantity: Very poor.

The above facts can be seen from the above table.

That is, the graft copolymer obtained by graft polymerization of a rubber having a particle size of 0.25-0.40 μm and a rubber of 0.50-1.0 μm, respectively, showed physical properties such as impact resistance, fluidity, and appearance. Rubbers having a diameter of about 0.50-1.0 μm have a large amount of coagulants generated during the reaction due to deterioration of stability during graft polymerization, and thus have difficulty in using the rubber.

In addition, the graft copolymer obtained by mixing the rubber of 0.25-0.40㎛ and the rubber of 0.50-1.0㎛ in advance before the graft polymerization and performing the graft reaction has a difference in surface area per volume between the small rubber and the large rubber during the graft reaction. Due to the difficulty in uniform graft reaction to each particle, the impact resistance and high elongation were not satisfied at the same time.

However, the graft polymer prepared according to the present invention was excellent in the impact resistance and elongation characteristics of the resin finally obtained by allowing a uniform graft reaction to the particle size of each different rubber. On the other hand, when the total rubber latex used for the first and second graft reactions is 30-60 parts by weight, optimum physical properties can be obtained, and the rubber having a particle diameter of 0.25-0.40㎛ and the rubber of 0.50-1.0㎛ are 60- 95 parts by weight: It was found that the thermoplastic resin composition having excellent impact resistance and elongation characteristics was obtained when the graft polymer mixed with 40-5 parts by weight.

Claims (8)

In preparing a graft copolymer in which a rubber having an average particle diameter of 0.25-0.40 µm and a rubber of 0.50-1.0 µm are mixed, 30-60 parts by weight of the total butadiene rubbery polymer latex and 70-40 parts by weight of the monomer mixture A method for producing a thermoplastic resin composition having excellent impact resistance and elongation characteristics, comprising the following two-step reactions. 1) When the rubber having a particle size of 0.25-0.40㎛ is 60-95% by weight of the total rubbery polymer latex, 140 parts by weight of ion-exchanged water, a molecular weight regulator, and a polymerization initiator are added and then stirred with all the styrene and acryl. When some of the nitrile monomer mixture is added to reach 50-65 ° C., it is stirred for 10 to 1 hour and 30 minutes to swell most of the monomer into the rubber particles, followed by addition of a redox composition to prepare a primary graft latex. Step 1 and 2) in the presence of the first graft latex, the remaining amount of rubber (40-5% by weight) having an average particle diameter of 0.50-1.0 μm was added at a time, and then the temperature of the mixture was brought to 50-70 ° C. Next, a two-step reaction in which a residual amount of styrene and acrylonitrile monomer mixture, a molecular weight regulator, and a polymerization initiator are continuously added to prepare a secondary graft latex. The impact resistance and elongation of claim 1, wherein the monomer injection ratio during the first and second graft polymerization is polymerized at a first 10-40% and a second 90-60% of the total graft monomer mixture 100. A method for producing a thermoplastic resin composition having excellent characteristics. The method of manufacturing a thermoplastic resin composition having excellent impact resistance and elongation characteristics according to claim 1, wherein the redox composition is composed of ferrous sulfate and tetrasodium parophosphate. The method of claim 1, wherein in the preparation of the secondary graft latex, the polymerization temperature of the primary graft latex is at least 90% while the rubber temperature of 0.50-1.0㎛ is added at a time, the reactor temperature is characterized in that 50-70 ℃ A method for producing a thermoplastic resin composition having excellent impact resistance and elongation characteristics. The method of claim 1, wherein in the preparation of the secondary graft latex, 0.05-0.35 parts by weight of tertiary dodecyl mercaptan, which is a molecular weight regulator, is mixed with the secondary graft monomer mixture and continuously injected for 1 hour to 5 hours. A method for producing a thermoplastic resin composition having excellent impact resistance and elongation characteristics. According to claim 1, 0.1-0.45 parts by weight of the polymerization initiator Qman hydroperoxide during the preparation of the secondary graft latex is continuously added over 1 hour to 5 hours of the thermoplastic resin composition excellent in impact resistance and elongation characteristics Manufacturing method. The method of claim 1, wherein the production temperature of the thermoplastic resin composition excellent in impact resistance and elongation, characterized in that the reaction temperature at the first 60-75 ℃, the second 50-75 ℃ when producing the first and second graft latex Way. The method of manufacturing a thermoplastic resin composition having excellent impact resistance and elongation characteristics according to claim 1, wherein the solid content of the final graft latex is 38-44% after the completion of the graft reaction.