KR0166399B1 - Process for high impact resistant graft polymer - Google Patents

Abstract

The present invention relates to a method for producing a graft polymer having excellent impact resistance, wherein a rubber having an average particle diameter of about 0.25-0.40 µm and a rubber of about 0.50-1.0 µm is simultaneously used, and the total butadiene-based rubbery polymer latex 30-60 weight 70-40 parts by weight of the monomer mixture and the first step, and the first stage of the reaction to prepare a first graft latex by the presence of a rubber latex having an average particle diameter of 0.25-0.40㎛ In the presence of the prepared primary graft latex, a rubber latex having an average particle diameter of about 0.50-1.0 μm is added, followed by a two-step reaction in which the remaining graft monomer mixture is continuously added. It features.

Description

Method for preparing graft polymer having excellent impact resistance

The present invention relates to a novel method for preparing a graft polymer having excellent impact resistance, and more particularly, to a graft copolymer containing two or more kinds of rubbery polymers having different particle diameters, and a novel graft polymer having excellent impact resistance properties. It relates to a manufacturing method of.

In general, the thermoplastic resin composition having improved impact resistance is characterized in that, in the presence of rubber latex such as polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, monomers such as styrene and acrylonitrile may be coagulated, suspended, and bulk-suspended polymerization It can be prepared by graft polymerization by emulsion polymerization method. Compared with emulsion polymerization method, other polymerization method has many disadvantages such as polymerization time and polymerization operation, and there are many difficulties in preparing graft polymer having high rubber content. The emulsion polymerization method is used.

In this case, the particle size and particle size distribution of the rubber and the graft copolymerization method in the emulsion polymerization method greatly influence the physical properties of the impact resistance and fluidity of the final product, and the larger the particle diameter of the rubber in the impact resistant resin such as ABS resin It is known that physical properties such as impact resistance and workability are excellent, and thus, various methods for increasing the rubber particle diameter are well known.

However, when the particle diameter of the rubber latex used is larger than necessary, the mechanical stability of the emulsion is deteriorated, so that a large amount of coagulum is generated during the graft polymerization, and there are many difficulties in the practical application, and the physical properties such as impact strength and the appearance of the resin surface This has the disadvantage of greatly falling.

Thus, a method of mixing rubber having a large particle diameter and a medium particle diameter of rubbery polymer latex is known to improve physical properties such as impact resistance and fluidity while maximally suppressing coagulum generated during graft polymerization. Examples include a method of mixing an appropriate amount in advance before the graft reaction and then polymerizing an aromatic vinyl monomer and an unsaturated nitrile monomer. However, a copolymer obtained by mixing and grafting two or more kinds of rubber latexes having different particle diameters in advance is a rubber latex. Since the smaller rubber particles are larger than the larger rubber particles in the surface area per volume diameter of the particles, the large rubber particles that do not sufficiently undergo the graft reaction with the matrix resin are formed. Due to the low dispersibility, the improvement of physical properties such as impact resistance was poor, and in particular, large amounts of unplasticized particles (SAND SURFACE, PINHOLE) were generated on the surface of the resin, and thus the physical properties of the present invention were not sufficiently satisfied.

In addition, a method of graft-polymerizing a large-diameter rubber and a small-diameter rubber and mixing graft latexes or mixing powders obtained through a solidification and drying process are known. However, in this mixing method, the graft reaction performed in the presence of rubber latex having a particle diameter of 0.50 µm or more is not practical due to deterioration of mechanical stability of the emulsion during polymerization, and it is not practical to use the coagulated product in the final resin composition. By mixing, unplasticized particles appear on the appearance of a molded article such as an extrusion sheet. On the other hand, if the amount of emulsifier is significantly increased to suppress the occurrence of such coagulants, the physical property decreases significantly due to the generation of gas on the surface of the molded article during injection molding due to the excessive amount of emulsifier, It is not preferable because the manufacturing cost rises.

The present inventors improve the industrially advantageous graft manufacturing method while making the above problems, and also produce a thermoplastic resin composition having excellent physical properties such as excellent impact resistance and fluidity, and thus, in various structural materials such as automobiles and buildings, etc. The present invention has been completed to provide a resin having excellent mechanical strength such as impact resistance, which is urgently required.

As a result of earnestly examining to achieve the above object, in preparing a graft polymer in which a rubber having an average particle diameter of about 0.25-0.40 μm and a rubber having an average particle size of about 0.50-1.0 μm are mixed, each rubber particle diameter In order to have an appropriate graft ratio in consideration of the surface area per unit volume, first, a rubber latex having a particle size of 0.25-.040㎛ is present in the graft polymerization system, and a part of the graft monomer mixture is added to polymerize to an appropriate conversion rate. Graft by a first step of preparing the first graft latex, and by adding a rubber having a particle size of about 0.50-1.0 μm in the presence of the first graft latex and continuously adding the remaining amount of the graft monomer mixture When the reaction is completed and combined into a two-step reaction to prepare a second graft latex, the reaction is uniform, resulting in increased polymerization stability. Due to this, the coagulum generated during the reaction may be minimized, and the uniform graft reaction may be performed on the large and small rubber particle diameters, thereby obtaining a thermoplastic resin composition having excellent physical properties such as impact resistance and fluidity.

Hereinafter, the present invention will be described in detail.

The rubbery polymer latex that can be used in the present invention contains 70% by weight or more of butadiene in a copolymer of an aromatic vinyl compound such as polybutadiene, butadiene-styrene, alphamethyl styrene, and a copolymer of acrylic compounds such as butadiene-acrylic acid and methacrylic acid. Latexes containing copolymers of butadiene and other copolymerizable monomers can be used.

The average rubber particle diameter of these rubbery polymer latexes is preferably about 0.25-0.40 µm in the primary graft reaction, and preferably about 0.50-1.0 µm in the secondary graft reaction. Particularly, rubber having a large particle diameter of 0.50-1.0 μm used in the secondary graft reaction is rubber latex prepared by agglomeration method after rubber or particle size distribution of 0.03-0.10 μm in advance. Although any one may be used, more preferably, the particle size distribution is distributed at the same time as the particle size of 0.1-0.18㎛ and the particle size of 0.5-1.0㎛, but 0.1-0.18㎛ particle: 0.5-1.0㎛ particle distribution Rubber latex with a ratio of 5-30: 95-70%.

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

1) Preparation of Primary Graft Latex

[First Method]

Butadiene-based rubbery polymer latex having an average particle diameter of 0.25-0.40 μm, an emulsifier, a redox composition, and ion-exchanged water were added and stirred, and the temperature of the reactor was raised to 60-75 ° C., and then the mixture temperature was 60-75 ° C. When reached, a portion of one or two or more monomer mixtures selected from an aromatic vinyl monomer and an unsaturated nitrile monomer, which are graft monomers, a molecular weight regulator and a polymerization initiator were added by continuous dosing for 30 minutes to 2 hours. By graft reaction in the temperature range of the first-grafted graft monomer is mostly polymerized to produce a first graft latex up to 90% conversion.

[Method 2]

In the presence of butadiene-based rubbery polymer 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, molecular weight modifiers, polymerization initiators and ions After adding and stirring the exchanged water, the temperature of the reactor was increased to 50-65 ° C, and when the temperature of the mixture reached 60-75 ° C, stirring was continued for 10 minutes to 1 hour 30 minutes, and most of the monomers swelled into the rubber particles. After graft reaction at a temperature range of 65-75 ° C. by adding a redox composition, most of the first-grafted graft monomers are polymerized to prepare a primary graft latex having a conversion rate of 90% or more.

2) Preparation of Secondary Graft Latex

In the presence of the prepared primary graft polymer latex, butadiene-based rubbery polymer latex having an average particle diameter of 0.50-.10 µm was added at a time to bring the reactor internal temperature to 50-70 ° C., followed by the remaining amount of the graft monomer mixture. And the first input residue of the molecular weight regulator and the polymerization initiator was continuously added over 1 to 5 hours, at which time the reaction temperature was in the range of 50-75 ° C., and the final polymerization conversion was 90-98% and the solid content was 38-44%. It is a method for producing a resin composition composed of a two-step graft reaction for preparing tea graft 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 the graft ratio was measured after basis weight.

In order to meet the object of the present invention, the graft rate should be 45-70% by weight. If the graft ratio is lower than the above range, 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 article during extrusion or injection, which lowers the surface glossiness. This can lead to a decrease in physical properties.

The monomers usable in the present invention include styrene, alpha methyl styrene and 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 polymer 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. Preferably, 70-40 parts by weight of the styrene and acrylonitrile monomer mixture (the styrene and acrylonitrile monomer composition ratio is 73:27) is preferable.

In more detail, the styrene and acrylonitrile monomer mixtures were mixed at a ratio of 10-40% with respect to the total monomer mixture 100 in the presence of 60-95% by weight of the total rubber latex of a rubber having an average particle diameter of 0.25-0.40 µm. In the first graft reaction, a residual amount of rubber (40-5% by weight) having an average particle diameter of 0.50-1.0 μm was added in the presence of the prepared first graft latex. It is preferable to copolymerize 90-60% of styrene and acrylonitrile monomer mixtures by continuous dosing.

If the content of the total rubbery latex is less than the above range, the impact resistance of the resin is lowered, and if it is exceeded, 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. The appearance is deteriorated. On the other hand, if the input amount of the large-diameter rubber of 0.25-0.40㎛ and the large-diameter rubber of 0.50-1.0㎛ is smaller than the above range, it is difficult to expect the physical properties such as the impact resistance. Due to the deterioration of a large amount of coagulated matter, which results in unplasticized particles appearing on the surface of the molded article, resulting in a deterioration in appearance and deterioration of glossiness and rather impact properties such as impact strength.

Of the monomers used in the graft reaction, when the input ratio of the monomers used in the first and second graft reactions is out of the above range, the composition and amount of the graft monomers inside and outside the rubber may not be appropriate. 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 is not preferable, and when the polymerization rate is high, the stability of the graft polymerization system is deteriorated. Problems tend to occur when coagulation occurs. 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. Examples thereof include fatty acid metals such as sodium laurate, sodium oleate and potassium oleate, sodium lauryl sulfate, sodium naphthalene sulfonate, Alkali metasulfonate of allyl sulfonic acid, such as sodium isopropyl naphthalene sulfonate, potassium rosinate, etc. are mentioned. Among them, one or two or more mixed emulsifiers selected from potassium oleate, sodium lauryl sulfate and potassium rosinate are preferable. The amount of these used is preferably 0.4-2.5 parts by weight, and if it is used less than the above range, a large amount of coagulant is generated in latex, which is not preferable, and when it is used excessively, it is difficult to control physical properties such as graft rate of graft polymer due to excessive generation of non-grafted polymer. In addition, the injection molding may cause physical properties deterioration due to gas generation on the appearance of the molded article.

As the molecular weight modifier that can be used in the present invention, it is preferable to use a molecular weight modifier such as a mercaptan having 8 to 18 carbon atoms or an organic halogen compound, and the amount of these used is 0.05-0.035 parts by weight in the first graft reaction and the second graft reaction. 0-0.35 parts by weight is preferred. The polymerization initiator may be a fat-soluble initiator such as cumene hydroperoxide, benzoyl peroxide, dicumyl peroxide, and water-soluble initiators such as ammonium persulfate, potassium persulfate, potassium carbonate, but preferably cumene hydroperoxide and benzoyl. 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 in the first graft reaction, 0.10-0.45 parts by weight in the second graft reaction, the molecular weight regulator and polymerization initiator used in the secondary graft reaction is uniform graft polymerization and molecular weight And continuous feeding over 1 to 5 hours in order to uniformly induce molecular weight distribution.

The prepared graft latex was solidified with 0.5-1.5% sulfuric acid aqueous solution and dried to obtain a white powder, followed by mixing the styrene-acrylonitrile copolymer (hereinafter referred to as SAN resin) in an appropriately prepared content. Through extrusion and injection processes, it is possible to produce ABS resin having excellent impact resistance and fluidity.

Hereinafter, the present invention will be described in detail through examples.

Example 1

1) Preparation of Primary Graft Copolymer Latex

40.0 parts of butadiene rubbery latex (hereinafter referred to as `` latex-1 '') having an average particle diameter of 0.32 µm and a gel content of 76 wt% in a 30L reactor equipped with a stirrer, a heating device, a cooling device, a condenser, a continuous input device of monomers and a polymerization initiator. (Parts by weight), 140 parts of ion-exchanged water, 0.8 part of potassium rosinate, 0.20 part of tetrasodium parophosphate, and 3.0 parts of acrylonitrile, 7.0 parts of styrene, 0.13 parts of tisheridodecyl mercaptan and cumene hydride while stirring. The reaction temperature was raised to 60 ° C while adding 0.13 parts of loper oxide. When the temperature of the mixture reaches 60 ° C, stirring is continued for 40 minutes, and then 0.05 part of ferrous sulfate and 0.30 part of dextrose are added and the reaction is started to reach 70 ° C. After the polymerization, the polymerization conversion reached 90% or more to terminate the reaction to prepare a first graft latex.

2) Preparation of Secondary Graft Copolymer Latex

In the presence of the prepared primary graft latex, 10.0 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 wt% were added at once. While the temperature in the reactor was brought to 65 ° C. and stirred for 20 minutes, 28.0 parts of styrene, 12.0 parts of acrylonitrile and 0.17 parts of tisoridodecyl mercaptan were placed in a stirred container, stirred for 10 minutes, and continuously added for 3 hours. 0.30 parts of hydroperoxide was continuously added over 3 hours to proceed with the secondary graft reaction. When the monomer and polymerization initiator were added, the reaction was continued for 40 minutes and the reaction was terminated. At this time, the reaction temperature was slowly 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 end of the polymerization was 97%, the solid content of the latex obtained was 40.7%. .

* 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 weighed.

The coagulum was 0.17 after completion | finish of reaction of Example 1. 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 and 60 parts of SAN (weight average molecular weight 130,000) and 60 parts of the graft copolymer were mixed with a stabilizer and a lubricant, followed by injection molding to prepare specimens for measurement of physical properties.

Example 2

1) Preparation of Primary Graft Copolymer Latex

40.0 parts of latex-1, 140 parts of ion exchange part, 0.8 part of potassium rosinate, 0.05 part of ferrous sulfate, 0.30 part of dextrose, and 0.20 part of tetrasodium parophosphate were introduced into the reactor, and the temperature was raised to 70 ° C while stirring. When the mixture reaches 70 ° C., 3.0 parts of acrylonitrile, 7.0 parts of styrene, and 0.13 parts of tisery dodecyl mercaptan are placed in a stirred container, stirred for 10 minutes, and continuously charged over 1 hour while cumene hydroperoxide 0.13 Part was continuously injected over 1 hour to proceed with the graft reaction. At this time, the reaction temperature is 70 ℃, the polymerization is continued for 10 minutes when the addition of the monomer, the molecular weight regulator, the polymerization initiator is completed, the reaction is terminated when the polymerization conversion rate reaches 93% or more to prepare a first graft latex.

2) Preparation of Secondary Graft Copolymer Latex

It carried out similarly to the conditions of Example 1.

Example 3

The same procedure as in Example 1 was conducted except that 10.5 parts of styrene and 4.5 parts of acrylonitrile were used for the first graft reaction, and 24.5 parts of styrene and 24.5 parts of acrylonitrile were used for the second graft reaction.

Example 4

The same procedure as in Example 2 was conducted except that 10.5 parts of styrene and 4.5 parts of acrylonitrile were used for the first graft reaction, and 24.5 parts of styrene and 24.5 parts of acrylonitrile were used for the second graft reaction.

Comparative Example 1

40 parts of latex-1, 10 parts of latex-2, 140 parts of ion-exchanged water, 0.8 parts of potassium rosinate, and 0.3 parts of dextrose were added to the reactor, and then stirred, 3.0 parts of acrylonitrile, 7.0 parts of styrene, and tiserydodecylmer. 0.13 parts of captan and 0.15 parts of cumene hydroperoxide were 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 sodium parophosphate were added for polymerization for 1 hour. After completion of the first graft polymerization, 28.0 parts of styrene, 12.0 parts of acrylonitrile, and 0.17 parts of tisheridodecyl mercaptan were added to a stirred container for 10 minutes, followed by continuous injection for 3 hours, and 0.3 parts of cumene hydroperoxide. It was added continuously over 3 hours to proceed with the secondary graft reaction. When the monomer and polymerization initiator were added, the reaction was continued for 40 minutes and the reaction was terminated. At this time, the reaction temperature was gradually progressed to start the second graft reaction at 70 ℃ to reach 75 ℃, the evaluation after the end of the polymerization was measured in the same manner as in Example 1.

Comparative Example 2

The same procedure as in Comparative Example 1 was conducted except that 10.5 parts of styrene and 4.5 parts of acrylonitrile were used for the first graft reaction, and 24.5 parts of styrene and 24.5 parts of acrylonitrile were used for the second graft reaction.

Comparative Preparation Example 1

Except for using 50 parts of latex-1 in the graft reaction was prepared in the same manner as in Comparative Example 1, the coagulation after the reaction was 0.15%.

Comparative Preparation Example 2

Except for using 50 parts of the latex-2 graft reaction was prepared in the same manner as in Comparative Example 1, the coagulation after the reaction was 4.43%.

Comparative Example 3

The graft polymer of Comparative Example 1 and the graft polymer latex of Comparative Example 2 were mixed latex at 20:80, and then solidified and dried to evaluate various properties.

[Comparative Example 4]

After mixing the graft polymer of Comparative Preparation Example 1 and the graft polymer Latex of Comparative Preparation Example 2 by coagulation and drying at 20:80, the overall physical properties were evaluated.

Physical property evaluation results for Examples 1-4 and Comparative Example 4-1 are shown in Table 1 below.

Claims (6)

30-60 parts by weight of the total butadiene-based rubbery polymer latex and the monomer mixture 70-40 weight 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 together. 1) 140 parts of ion-exchanged water, an emulsifier and a redox composition are added to 60-75 ° C. in a state in which a rubber having an average particle diameter of 0.25-0.40 μm is present in 60-95% by weight of the total rubber latex. When the temperature of the mixture reaches 60-75 ° C. after the temperature is raised, 10-40% by weight of a styrene and acrylonitrile monomer mixture, a molecular weight regulator and a polymerization initiator are grafted in a continuous manner to obtain a polymerization conversion rate of 90% or more. 1 step reaction for preparing the primary graft latex, and 2) a mixture of the remaining amount of rubber (40-5% by weight) having an average particle diameter of 0.50-1.0 µm in the presence of the prepared primary graft latex at a time. of After the temperature is 50-70 ° C, the remaining amount (90-60% by weight) of styrene and acrylonitrile monomer mixture, molecular weight control agent and polymerization initiator are continuously added to prepare a second graft latex. A method for producing a graft polymer having excellent impact resistance. The method for producing a graft polymer having excellent impact resistance according to claim 1, wherein the monomer composition ratio of styrene and acrylonitrile is 73:27 for polymerization. The method of claim 1, wherein the graft monomer mixture, the molecular weight modifier, and the polymerization initiator are continuously added over 30 minutes to 2 hours when preparing the first graft latex. 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 μm is added at a time to bring the temperature of the reactor to 50-70 ° C. The manufacturing method of the graft polymer excellent in impact resistance. The method of producing a graft polymer having excellent impact resistance according to claim 1, wherein the molecular weight modifier, the secondary graft monomer mixture, and the polymerization initiator are continuously added for 1 to 5 hours during the preparation of the secondary graft latex. . The method of claim 1, wherein the reaction temperature is 60-75 ° C. and 50-75 ° C. for the first and second graft latexes.