KR100478977B1 - Method of Preparing ABS Resin Using Agglomerated Rubber Latex - Google Patents

Abstract

Method for producing ABS resin using agglomerated rubber latex of the present invention comprises: (1) a first step of pretreatment of seed synthetic rubber latex by mixing and stirring anionic emulsifier and nonionic emulsifier in seed synthetic rubber latex; (2) a second step of pretreating the particle size-enhancing agent by mixing the unsaturated acid-containing copolymer latex with ion-exchanged water, a nonionic emulsifier and an electrolyte to adjust the solids content to 1 to 10% by weight and the pH to 5 to 11; (3) a third step of preparing a coagulated rubber latex by adding the pretreated particle size-enhancing agent to the pretreated seed synthetic rubber latex in a batch and re-adjusting the pH to 9 to 12; And (4) a fourth step of graft polymerization by adding a monomer mixture consisting of acrylonitrile and styrene to the agglomerated rubber latex prepared above.

Description

Method of Preparing ABS Resin Using Agglomerated Rubber Latex}

Field of invention

The present invention relates to a method for producing an ABS resin rule having excellent physical properties using agglomerated rubber latex. More specifically, the present invention relates to agglomerated rubber latex prepared by adding a particle size-enhancing agent pretreated at a solid content of 1-10% by weight and pH 5-11 to a seed synthetic rubber latex pretreated using an anionic emulsifier and a nonionic emulsifier. It relates to a method for producing an acrylonitrile-butadiene-styrene copolymer (hereinafter, referred to as ABS resin), which is prepared by adding a monomer mixture composed of acrylonitrile and styrene monomers at a predetermined ratio.

Background of the Invention

ABS resin is a copolymer of acrylonitrile monomer and butadiene monomer styrene monomer. They are in harmony with various physical properties such as stiffness, weather resistance, chemical resistance, impact resistance, glossiness, moldability in ABS resin.

In general, the ABS resin manufacturing process proceeds by graft polymerization with a certain amount of styrene and acrylonitrile to disperse polymerization of butadiene monomers through conventional emulsion polymerization to protect the compatibility of butadiene rubber with styrene and acrylonitrile. Or it is obtained through an extrusion process of mixing at a constant temperature with the styrene and acrylonitrile copolymer obtained through the bulk polymerization.

Butadiene rubber in ABS resin improves the impact resistance, but in the entire ABS resin manufacturing process, since it is manufactured by a conventional emulsion polymerization method with a long polymerization time, the ABS resin manufacturing time is influenced. That is, butadiene rubber should have a particle size of a predetermined size or more in order to exhibit impact resistance in the ABS resin, but when prepared through emulsion polymerization, a long time polymerization reaction time is required to polymerize the butadiene rubber of a predetermined particle size or more.

In order to reduce the production time of the rubber latex, the polymerization time has been shortened by copolymerization with styrene or acrylic monomers, but the polymerization time has not been drastically reduced.

Accordingly, various methods of enlarging the particle size in a short time after preparing butadiene rubber latex or copolymer rubber latex having a relatively short polymerization time have been proposed. These methods are freeze-incorporation of small particle rubber latex or enlarging the particle size by mechanical or chemical methods.

These methods are well known methods, but there is a problem that the stability after the particle size enlargement, or change over time occurs, and coagulum occurs a lot. In addition, even if these problems are solved, the synthetic rubber latex having a large particle size in a short time expresses high impact physical properties when applied to ABS resin, but causes problems such as reduced fluidity and reduced gloss.

In order to solve the above problems, the present inventors adjust the manufacturing conditions and the graft polymerization conditions of the cohesive rubber latex, thereby improving physical properties such as fluidity deterioration and glossiness deterioration generated when the cohesive rubber latex is applied to the ABS resin. Rather, it has begun to develop a method for producing an ABS resin that shortens the overall polymerization time.

An object of the present invention is to provide a method for producing an ABS resin having excellent reaction stability in the production of agglomerated rubber latex.

Another object of the present invention is to provide a method for producing an ABS resin in which coagulation product is reduced during the production of agglomerated rubber latex.

Still another object of the present invention is to provide a method for producing an ABS resin having a small change in particle diameter with time after aggregation.

Another object of the present invention is to provide a method for producing an ABS resin that shortens the overall polymerization time.

Still another object of the present invention is to provide a method for producing an ABS resin which improves physical properties such as impact strength, fluidity, glossiness, and the like.

The above and other objects of the present invention can be achieved by the present invention described below. Hereinafter, the details of the present invention will be described below.

Method for producing ABS resin of the present invention (1) a first step of pretreatment of the seed synthetic rubber latex by mixing and stirring anionic emulsifier and nonionic emulsifier in the seed synthetic rubber latex; (2) a second step of pretreating the particle size-enhancing agent by mixing the unsaturated acid-containing copolymer latex with ion-exchanged water, a nonionic emulsifier and an electrolyte to adjust the solids content to 1 to 10% by weight and the pH to 5 to 11; (3) a third step of preparing a coagulated rubber latex by adding the pretreated particle size-enhancing agent to the pretreated seed synthetic rubber latex in a batch and re-adjusting the pH to 9 to 12; (4) A fourth step of graft polymerization by adding a monomer mixture consisting of acrylonitrile and styrene to the agglomerated rubber latex prepared above. Hereinafter, a detailed description of each of these steps is as follows.

(1) First step: pretreatment of seed synthetic rubber latex

Seed synthetic rubber latex used in the present invention is prepared by a conventional emulsion polymerization method. As the emulsifier used in the polymerization step, an anionic emulsifier and a nonionic emulsifier are mixed and used, and at least one anionic emulsifier and a nonionic emulsifier are used. The mixing and stirring process can be easily carried out by those skilled in the art.

Examples of the seed synthetic rubber latex include, but are not limited to, polybutadiene, butadiene-styrene copolymer, butadiene-α-methylstyrene copolymer, butadiene-acrylate copolymer, butadiene-methacrylate copolymer, and the like. .

The particle size of the seed synthetic rubber latex is preferably in the range of 800 to 1,600 kPa. When the particle size is 800 kPa or less, the viscosity of the rubber latex is increased, not only the conveyance is easy, but also causes a problem of forming a local large particle size without uniform particle size enlargement when the particle size increasing agent is added. On the other hand, if the particle size is more than 1,600Å, the polymerization time of the seed synthetic rubber latex is increased.

In addition, the solid content of the seed synthetic rubber latex of the present invention is preferably 30 to 50 weight percent. If the solid content is less than 30% by weight, the solid content of the aggregated final synthetic rubber latex is low, which is disadvantageous for commercial ABS resin production. On the other hand, if the solid content of the seed synthetic rubber latex is 50% by weight or more, it is not only a problem of polymerization stability, but also a high viscosity after polymerization, which causes local large particle curing or coagulation.

The pretreatment of the seed synthetic rubber latex of the present invention comprises 1: 9 to 9: 1 weight ratio of anionic emulsifier and nonionic emulsifier in the seed synthetic rubber latex having the solid content of 30 to 50% by weight, preferably 2: Pretreatment is carried out by adding and stirring at a ratio of 8 to 8: 2.

The anionic emulsifier used in pretreatment of the seed synthetic rubber latex is rosin acid soap, sodium lauryl sulfate, sodium oleate, potassium oleate, dodecyl Sodium dodecyl benzene sulfonate and aerosols, which are succinic acid derivatives of various sulfonic acids.

The nonionic emulsifier may be a polyethylene oxide condensate, a polyethylimide condensate, a fatty acid ester of a polyoxy compound, or the like.

(2) Second step: pretreatment of particle size increasing agent

As the particle size increasing agent used in the present invention, copolymer latex containing unsaturated acid is applied. As the monomer for producing the copolymer latex, an unsaturated acid monomer having a carboxyl group is preferable.

Examples of the monomer having a carboxyl group include acrylic acid, methacrylic acid, methyl acrylic acid, itaconic acid, crotonic acid, fumaric acid, Methylene unsaturated carboxylic acids such as maleic acid; Acrylate monomers such as methyl methacrylate, methyl acrylate and ethyl acrylate copolymerizable with these; C4-6 conjugated double bond monomers, such as butadiene and isoprene; Monovinyl aromatic hydrocarbon monomers such as styrene, α-methylstyrene, vinyltoluene, and chlorostyrene; And acrylonitrile, methacrylonitrile monomers. The particle size-enhancing agent is preferably prepared by copolymerizing at least one or more unsaturated acid monomers.

In addition, the solid content of the unsaturated acid-containing copolymer latex of the present invention is not particularly limited, but usually 10 to 50% by weight is preferred.

The unsaturated acid-containing copolymer latex is mixed with an appropriate amount of ion-exchanged water, a nonionic emulsifier, and an electrolyte, followed by pretreatment by adjusting the solids content of the copolymer latex to 1 to 10% by weight and the pH to 5 to 11. It is preferable that the particle size-enhancing agent adjust the pH to 5 to 11 because it is most stable when the pH is in the above range.

As the nonionic emulsifier used to pretreat the unsaturated acid-containing copolymer latex, a polyethylene oxide condensate, a polyethylimide condensate, and a fatty acid ester of a polyoxy compound may be used.

In addition, it is preferable to use an aqueous potassium carbonate solution (2%) as the electrolyte.

(3) Step 3: Preparation of agglomerated rubber latex (enlarge particle size of seed synthetic rubber latex)

Agglomerated rubber latex of the present invention is prepared by a method of batch-injecting the particle size-adding agent pretreated in the second step to the seed synthetic rubber latex pretreated in the first step.

At this time, it is preferable to use the particle size-enhancing agent in the range of 0.1 to 20 parts by weight based on 100 parts by weight of the solid content of the seed synthetic rubber latex. If less than 0.1 parts by weight of synthetic rubber latex has a small capacity to enlarge, there is a lot of PASS latex, it is not necessary to control the enlargement capacity through pre-treatment, when used in excess of 20 parts by weight, the emulsifier used for pretreatment Since the content of ion-exchanged water and electrolytes increases, the solid content is low since the particle size enlargement is not preferable. More preferably, it is good to use in the range of 1-10 weight part.

The large particle size of the present invention was prepared by re-adjusting the pH from 9 to 12 with a batch of a particle size-enhancing agent adjusted to a solid content of 1 to 10% by weight and a pH of 5 to 11 in a pretreated seed synthetic rubber latex as described above. Synthetic rubber latex having can be prepared.

When the particle size-enhancing agent whose solid content is 1 to 10% by weight and the pH is adjusted to 5 to 11 is added to the pretreated seed synthetic rubber latex, it is preferable to rapidly add within 1 second to 10 minutes.

In addition, when the particle size-adding agent is added to the seed synthetic rubber latex, the temperature is preferably maintained at 50 ° C to 90 ° C.

The time for enlarging the particle size is preferably 10 minutes to 4 hours, and the pH is preferably adjusted to 9 to 12 while the particle size is enlarged.

(4) 4th step: Graft polymerization of agglomerated rubber latex

Polymerization of the cohesive rubber latex of the present invention is polymerized by mixing 5 to 20 parts by weight of acrylonitrile monomer and 20 to 50 parts by weight of styrene monomer to 40 to 70 parts by weight of the agglomerated rubber latex prepared in the third step. At this time, the composition of the mixture of acrylonitrile monomer and styrene monomer preferably has 30 to 50 parts by weight.

When the content of the agglomerated rubber latex in the graft polymerization is 40 parts by weight or less, the graft SAN formed on the surface of the rubber may be uniform, and thus the fluidity and gloss may be excellent. There is a problem in that the SAN generation amount is increased to reduce the graft copolymer production efficiency. On the other hand, when the content of agglomerated rubber latex is 70 parts by weight or more, due to the lack of a monomer forming graft copolymerization, the rubber surface cannot be uniformly graft-polymerized, thereby causing entanglement between rubbers and deterioration of compatibility with SAN in the manufacture of ABS resin. Problems occur such as to lower the overall physical properties of the ABS resin.

In the graft polymerization of agglomerated synthetic rubber latex, a mixture of monomers composed of acrylonitrile and styrene is added to the reactor with a molecular weight modifier, an emulsifier, a polymerization initiator, ion-exchanged water and a reducing agent. After raising the temperature, the catalyst compound is added to form a first graft polymerization, and then a residual amount of the monomer mixture is gradually added for 1 to 3 hours to form a second graft polymerization.

If the monomer mixture in the first graft polymerization is less than 15% of the total monomer mixture, the efficiency decreases due to the increase in the total polymerization time due to the increase in the amount of the monomer mixture used for the second graft polymerization. On the other hand, when 55% or more of the monomer mixture is added during the first graft polymerization, it is difficult to control the molecular weight of the graft polymerization SAN, which causes a decrease in physical properties when applied to the ABS resin.

However, when the amount of the monomer mixture added to the first graft polymerization is increased, the monomer mixture used in the second graft polymerization is reduced, thereby reducing the total graft polymerization time.

Therefore, only when the content of the monomer mixture, the molecular weight regulator, the initiator, and the like is properly adjusted during the first graft polymerization, the total graft polymerization time can be minimized without deteriorating the physical properties of the ABS resin.

Specific examples of molecular weight regulators introduced during the first graft polymerization in the present invention include mercaptans such as alpha methyl styrene duplex or tertiary dodecyl mercaptan, and 0.02% to 1.0% of the monomers used for the first graft polymerization. It is possible to minimize the total graft polymerization time without lowering the physical properties of ABS resin.

In addition, specific examples of the initiator include tertiary butyl peroxide, tertiary butyl peroxy benzoate, cumene hydroperoxide, and the like, in the range of 0.03% to 1.0% of the monomer used for the first graft polymerization. It is possible to minimize the total graft polymerization time without deteriorating the physical properties of the ABS resin to be added in the range of 0.8 times to 1.5 times based on the molecular weight regulator.

When graft polymerizing agglomerated rubber latex, the stirring conditions and polymerization temperature of the reactor change the graft copolymerization behavior. In the present invention, the graft polymerization of the coagulated rubber latex is preferably stirred in the range of 130 rpm to 400 rpm, and the polymerization temperature is preferably in the range of 50 ° C to 75 ° C.

In the case of graft polymerization, when the stirring rpm is 130 or less, stirring is locally performed to reduce the uniformity of the graft polymerization, and when the rpm is 400 or more, the polymerization graft polymerization stability is rapidly lowered to generate a coagulated product.

In addition, when the polymerization temperature is 50 ℃ or less, the polymerization stability is excellent, but the polymerization rate is reduced to reduce the graft polymerization production efficiency. The higher the polymerization temperature, the shorter the graft polymerization time. However, the polymerization stability of 80 ° C. or higher is 77.3 degrees at the boiling point of acrylonitrile, resulting in the breakdown of micelles due to the foaming, resulting in reduced polymerization stability.

In the stirring conditions of 130rpm to 400rpm, because the agglomerated rubber latex is metastable and the particle size is enlarged, the agglomerated particles are loosened depending on the stirring conditions and temperature, or the reaggregation phenomenon is caused by the activity of the particle size increasing agent. It can give a particle diameter change of 10Å to 2000Å depending on the temperature. The particle size change of the agglomerated rubber latex during the graft polymerization has a great influence on the physical properties of the ABS resin.

The present invention will be further illustrated by the following examples, which are only described for the purpose of illustrating the present invention and are not intended to limit the protection scope of the present invention.

Example

(1) Step 1: Preparation and pretreatment of seed synthetic rubber latex

Seed synthetic rubber latex is 130 parts by weight of ion-exchanged water, 100 parts by weight of butadiene, 0.7 parts by weight of t-dodecyl mercaptan (t-DDM), 3.0 parts by weight of alkylbenzenesulfonate, 1.0 part by weight of potassium carbonate and potassium persulfate 0.5 It was prepared by polymerizing parts by weight at a reaction temperature of 70 ° C. for 9 hours. The prepared synthetic rubber latex had a particle size of 1450 Å and a solid content of 45%. It was.

2 parts by weight of rosin acid soap, an anionic emulsifier, and 2 parts by weight of polyethylimide condensate as a nonionic emulsifier to 100 parts by weight of the seed synthetic rubber latex prepared as described above (solid content 45% by weight). Was pretreated.

(2) second step: preparation and pretreatment of particle size increasing agent

The copolymer latex, which is a particle size-enhancing agent, contains 185 parts by weight of ion-exchanged water, 40 parts by weight of butadiene, 20 parts by weight of methacrylic acid, 40 parts by weight of ethyl acrylate, 5.0 parts by weight of potassium oleate, 0.5 parts by weight of potassium carbonate and 0.5 of potassium persulfate. The polymer was prepared by polymerization by weight at a reaction temperature of 70 ° C. for 6 hours. A copolymer latex having a particle size of 750 mm 3, a solid content of 35% by weight, and a pH of 2.5 was prepared.

To 100 parts by weight (35% by weight of solid content) of copolymer latex, the particle size-enhancing agent prepared above, 2 parts by weight of polyethylimide condensate as a nonionic emulsifier, 150 parts by weight of ion-exchanged water, and aqueous potassium carbonate solution (2%) Mixing and stirring were carried out to adjust the solid content to 10 wt% and the pH to 7.

(3) Step 3: Preparation of Cohesive Rubber Latex (Enlarged Particle Size)

100 parts by weight of the pretreated seed synthetic rubber latex was introduced into the reactor, and the temperature was raised to 65 ° C. while stirring at 150 rpm, and then 5 parts by weight of the pretreated particle size-enhancing agent was added at once. Aggregated particle size was measured by NICOMP 370 (particle size analyzer) from 1 hour to 96 hours after the particle size increasing agent. In the same manner, the particle diameter was increased twice, and the change in particle diameter is shown in Table 1 below.

Production Example Pretreated Seed Synthetic Rubber Latex Pretreated Particle Expense Agent pH control Size increase P / size (Å) 1hr 4hr 12hr 48hr 96hr One 100 parts by weight 5 parts by weight 11.0 3797 3830 3805 3901 3911 2 3758 3902 3897 3895 3897

(4) Step 4: Graft Polymerization of Cohesive Rubber Latex

60 parts by weight of the agglomerated rubber latex prepared in Preparation Examples 1 and 2 of Table 1 (average particle size particle size 3904 kPa) was added to the graft polymerization reactor, 60 parts by weight of acrylonitrile monomer, 3.3 parts by weight of styrene monomer, 10.5 parts by weight of frostery 0.14 part by weight of dodecyl mercaptan, 0.2 part by weight of cumene hydroperoxide, 0.2 part by weight of potassium stearate, 0.3 part by weight of sodium hydroxide, and 140 parts by weight of ion-exchanged water, and then the temperature of the reactor was raised to 60 ° C. 0.003 parts by weight of ferrous iron and 0.15 parts by weight of tetrasodium parophosphate were added to carry out the first graft polymerization.

Secondary graft polymerization was continuously performed immediately after the reactor temperature reached 70 ° C. due to the heat of polymerization generated during the first graft polymerization. 6.7 parts by weight of acrylonitrile monomer, 19.5 parts by weight of styrene monomer and 0.2 parts by weight of terceridodecylmercaptan were mixed and stirred in the primary graft polymer, 0.2 parts by weight of cumene hydroperoxide and a reactor for 2 hours and 30 minutes at a constant rate, respectively. To the second polymerization was carried out.

At this time, the graft polymerization was performed by varying the stirring speeds at 170, 220, 280 and 330 rpm, respectively.

After the completion of the second polymerization, natural cooling was performed for 1 hour, and then the graft polymerization was terminated by adding an antioxidant along with forced cooling. After the polymerization, the polymerization rate was 97%. After the polymerization, the latex was coagulated with 1.0% sulfuric acid in a high speed stirring solution and washed and dried to obtain graft-ABS powder.

The properties of the latex after graft polymerization according to the change of stirring conditions are shown in Table 2 below.

Example Agitation Conditions during Graft Polymerization Latex Properties after Graft Polymerization Coagulum Graft efficiency Particle diameter One 170 rpm 0.115% 89% 4050 yen 2 220 rpm 0.123% 88% 3725 yen 3 280 rpm 0.145% 89% 3133Å 4 330 rpm 0.23% 91% 2863Å

Comparative Example 1

Graft polymerization was carried out using agglomerated rubber latex (particle size 3200 mm 3) obtained through conventional emulsion polymerization. The coagulant amount, graft efficiency and particle diameter of the prepared latex are shown in Table 3 below.

Comparative example Particle diameter of rubber latex Latex Properties after Graft Polymerization Coagulum Graft efficiency Particle diameter One 3200 yen 0.137% 88% 3590 yen

ABS resin composition preparation and evaluation

In order to evaluate the physical properties expressed in the ABS resin of the graft-ABS powder prepared in Examples 1-4 and Comparative Example 1, an ABS resin composition was prepared by the following method.

30 parts by weight of the graft copolymer, 27 parts by weight of acrylonitrile content, weight average molecular weight of 120,000, and 70 parts by weight of SAN copolymer having a molecular weight distribution of 1.88, 23 parts by weight of flame retardant, 1 part by weight of calcium stearate as stabilizer and ethylene 1 part by weight of bis steroidoid was mixed and extruded to prepare a test piece for measuring physical properties. The physical properties of each prepared specimen were evaluated and shown in Table 4 below.

Properties Example Comparative Example 1 One 2 3 4 Izod impact strength (1/4 "notch) ASTM D256 22 23 21 19 19 Flow Index (ASTM D1238) 6.6 6.5 6.7 6.6 6.5 Glossiness (ASTM D523) 99.0 99.2 99.3 99.2 98.0 Yellowness (ASTM D1925) 12.1 12.2 12.1 12.2 13.5 Whiteness (ASTM D1925) 89.9 90.2 90.5 90.1 88.9 Heat Deflection Temperature (ASTM D1525) 89 88 87 88 87 Specimen Surface Condition A A A A A

※ Specimen surface condition (A: Good B: Normal C: Poor)

As shown in Table 4, it can be seen that when agglomerated rubber latex is used in ABS resin, it exhibits physical properties equivalent to those of rubber latex prepared by conventional emulsion polymerization.

The present invention not only improves physical properties such as fluidity deterioration and glossiness deterioration generated by applying agglomerated rubber latex to ABS resin, but also shortens the overall polymerization time by controlling the conditions for producing agglomerated rubber latex and graft polymerization. It has the effect of providing the manufacturing method of an ABS resin.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (5)

(1) a first step of pretreating seed synthetic rubber latex by mixing and stirring anionic emulsifier and nonionic emulsifier to seed synthetic rubber latex; (2) a second step of pretreating the particle size-enhancing agent by mixing the unsaturated acid-containing copolymer latex with ion-exchanged water, a nonionic emulsifier and an electrolyte to adjust the solids content to 1 to 10% by weight and the pH to 5 to 11; (3) a third step of preparing a coagulated rubber latex by adding the pretreated particle size-enhancing agent to the pretreated seed synthetic rubber latex in a batch and re-adjusting the pH to 9 to 12; And (4) a fourth step of graft polymerization by adding a monomer mixture composed of acrylonitrile and styrene to the coagulated rubber latex prepared above; Method for producing an ABS resin using agglomerated rubber latex, characterized in that consisting of. The method of claim 1, wherein the seed synthetic rubber latex has a particle size of 800 to 1600 mm 3, the solid content is 30-50% by weight, the unsaturated acid-containing copolymer latex is characterized in that the solid content of 10-50% by weight. The manufacturing method of ABS resin using the coagulated rubber latex made into. The method of claim 1, wherein the anionic emulsifier is a rosin acid soap, sodium lauryl sulfate, sodium oleate, potassium oleate, dodecylbenzenesulfonate (sodium oleate) sodium dodecyl benzene sulfonate) and aerosol series which are succinic acid derivatives of various sulfonic acids. Method for producing an ABS resin using agglomerated rubber latex, characterized in that. The method of claim 1, wherein the ratio of the anionic emulsifier and the nonionic emulsifier of the first step is 1: 9 to 9: 1. The method according to claim 1, wherein the particle size-extension agent ranges from 0.1 to 20 parts by weight based on 100 parts by weight of the solid content of the seed synthetic rubber latex when the pretreated particle size-adding agent is added to the pretreated seed synthetic rubber latex of the third step. 1 second to within 10 minutes, the temperature is maintained at 50 to 90 ℃, the time for enlarging the particle size is 10 minutes to 4 hours, characterized in that the production method of ABS resin using agglomerated rubber latex.