KR101441314B1 - Acrylate-Styrene-Acrylonitrile Graft Copolymer Having Excellent Impact-resistance, Weather-resistance, and Dyeability Property, and Method for Preparing The Same - Google Patents

Abstract

The present invention relates to an acrylonitrile-styrene-acrylate (ASA) graft copolymer having a core-shell structure and a process for preparing the same, wherein the core of the ASA graft copolymer is a copolymer of an alkyl acrylate monomer Wherein the shell is formed by graft-polymerizing a styrene-based monomer and an acrylonitrile-based monomer to the core. Wherein the ASA graft copolymer resin comprises: sequentially polymerizing an alkyl acrylate monomer to prepare a tri-core rubbery polymer latex; And graft-polymerizing the styrene-based monomer and the acrylonitrile-based monomer with the tri-core rubbery polymer to form a shell layer. The ASA resin of the present invention is excellent in impact resistance, weather resistance, and colorability.

Description

TECHNICAL FIELD The present invention relates to an ASA graft copolymer excellent in impact resistance, weather resistance, and coloring property, and a method for producing the ASA graft copolymer.

The present invention relates to an ASA graft copolymer and a process for producing the same, and relates to an ASA graft copolymer excellent in impact resistance, weather resistance, and coloring property, and a process for producing the same.

In general, acrylonitrile-butadiene-styrene resin (hereinafter referred to as "ABS resin") has excellent impact resistance, mechanical strength, surface characteristics and processability and is widely used in electric / electronic products, Resin. However, since the ABS resin contains a double bond chemically unstable in the rubber component in the resin due to the nature of the resin, the rubber component can be easily aged by the ultraviolet rays, and therefore the weather resistance and light resistance are poor. It is relatively unsuitable for outdoor use where exposure to sunlight is relatively large. Therefore, in order to compensate for this, a method of post-processing such as painting or plating on an ABS resin molded article, or adding a large amount of a UV stabilizer during the extrusion processing of an ABS resin is used. However, the former is disadvantageous in that the process is complicated and the defect rate is high, and the latter is disadvantageous in that the production cost is increased and satisfactory long-term weatherability is not obtained.

In order to overcome the limitation of the use of such ABS resin, various resins known to have excellent weather resistance are used instead of ABS resin. Among them, acrylate-styrene-acrylonitrile resin (hereinafter referred to as ASA resin) Widely used.

The ASA resin is generally prepared by copolymerizing an acrylic graft polymer obtained by graft-polymerizing a vinyl cyanide compound and an aromatic vinyl compound by an emulsion graft polymerization method on an acrylic synthetic rubber, a vinyl cyanide-aromatic vinyl copolymer obtained by copolymerizing a vinyl cyanide compound and an aromatic vinyl compound Are mixed and extruded. At this time, by regulating the physical properties and content of the acrylic synthetic rubber, the acrylic graft polymer, and the matrix polymer, the vinyl cyanide-aromatic vinyl compound copolymer, a reinforcing material having a specific role is selectively added, have. Since the ASA resin is excellent in weatherability, light resistance, chemical resistance and heat resistance, it is suitable for use in exterior parts for outdoor use such as outdoor electric / electronic products, automobile exterior parts, and construction materials.

On the other hand, in order to use heat-resistant properties for outdoor use such as automobiles, alpha-methylstyrene matrix SAN resin was conventionally used in order to improve heat resistance of ASA resin, which is a weather resistant resin. However, a copolymer of a vinyl cyanide compound and an alpha-methylstyrene compound used for heat resistance has excellent heat resistance characteristics, but it causes a problem of appearance problems such as lowered injection stability and loss of gloss due to a large amount of generated gas. There was a problem that the coloring was poor because the color was very yellow.

Accordingly, in order to solve the above problems, the present inventors have developed an ASA graft copolymer having improved impact resistance, weather resistance and coloring property by structurally modifying the core design of an ASA graft copolymer having a core-shell structure It is early.

It is an object of the present invention to provide an ASA graft copolymer excellent in impact resistance, weather resistance, and colorability.

It is an object of the present invention to provide a process for producing an ASA graft copolymer excellent in impact resistance, weatherability, and colorability.

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

According to one embodiment of the present invention, there is provided an acrylonitrile-styrene-acrylate (ASA) graft copolymer having a core-shell structure, wherein the core is formed by sequentially polymerizing an alkyl acrylate monomer Wherein the shell is formed by graft-polymerizing a styrene-based monomer and an acrylonitrile-based monomer on the core. The present invention also provides an ASA graft copolymer.

According to another embodiment of the present invention, the core has an average particle diameter of 1,500 ANGSTROM to 4,500 ANGSTROM or less, a gel content of 80 to 95 wt.%, And a swelling index of 15 to 30.

According to another embodiment of the present invention, the cross-linking density of the triple-core rubbery polymer gradually increases in the order of the first core layer, the second core layer, and the third core layer.

According to another embodiment of the present invention, the particle size distribution of the triple core rubbery polymer may be unimodal, bimodal or trimodal.

According to another aspect of the present invention, there is provided a method for preparing a rubber composition, comprising: sequentially polymerizing an alkyl acrylate monomer to prepare a tri-core rubbery polymer latex; And graft-polymerizing the styrene-based monomer and the acrylonitrile-based monomer with the tri-core rubbery polymer to form a shell layer. The present invention also provides a method for producing the ASA graft copolymer.

According to another embodiment of the present invention, the step of preparing the triple-core rubbery polymer latex comprises the steps of (1) feeding an alkyl acrylate monomer into a reactor, stirring and stirring an emulsifier and ion- Lt; 0 > C, adding a polymerization initiator and maintaining the polymerization temperature at 70 to 75 DEG C to form a first core layer; (2) further adding an alkyl acrylate monomer, a crosslinking agent and a grafting agent to form a second core layer; And (3) further adding an alkyl acrylate monomer, a crosslinking agent and a grafting agent to form a third core layer to prepare a tri-core rubbery polymer.

According to another embodiment of the present invention, in the step of forming the shell layer, the redox-based catalyst mixture is added to the triple-core rubbery polymer latex and after stirring for 5 to 10 minutes, the styrene-based monomer, acrylonitrile- A polymerization initiator and a polymerization initiator at a polymerization temperature of 70 to 75 캜 for 2 to 5 hours, followed by polymerization to form a shell layer of the ASA graft copolymer.

The ASA graft copolymer of the present invention is excellent in impact resistance, weather resistance, and colorability.

Hereinafter, the present invention will be described in detail.

Acrylate - styrene- Acrylonitrile Graft  Copolymer (g- ASA )

As a representative example of the acryl-based graft copolymer, acrylate-styrene-acrylonitrile (hereinafter referred to as 'ASA') graft copolymer is obtained by grafting a monomer mixture composed of an aromatic vinyl compound and a vinyl cyanide compound onto an acrylic rubber, Are well known to those of ordinary skill in the art. ASA resin has better weather resistance and chemical resistance than ABS resin but has poor impact resistance and colorability. To overcome this problem, the inventors of the present invention have found that the crosslinking agent and the grafting agent can be used in a stepwise manner to crosslink the alkyl acrylate monomer Wherein the first core layer, the second core layer and the third core layer are formed on the first core layer, the second core layer and the third core layer, and the cross-linking density gradually increases in this order from the first core layer to the third core layer. . Thereafter, the styrene-acrylonitrile (SAN) copolymer shell layer is formed by graft-polymerizing the styrene-based monomer and the acrylonitrile-based monomer to the triple-core rubbery polymer, so that the ASA graft copolymer of the present invention is completed .

The ASA graft copolymer of the present invention has a weight ratio of triple core: shell of 20:80 to 80:20.

The ASA graft copolymer of the present invention preferably has an impact strength of not less than 30 kgcm / cm (1/8 "knotched) when measured according to ASTM 256 of a resin composition compounded with a SAN copolymer in a weight ratio of 4: 6, According to SAE J 1960, the value of DELTA E is preferably 3.0 or less.

Hereinafter, the acrylonitrile-styrene-acrylate (ASA) graft copolymer of the present invention will be described in more detail.

(A) a tri-core rubbery polymer

(a1) acrylate monomers

The core of the present invention is formed by polymerizing an acrylate monomer as an acrylic rubber. The acrylate monomer is an alkyl acrylate having 2 to 8 carbon atoms and is exemplified by acrylates such as methyl, ethyl, propyl, isopropyl, t-butyl, n-butyl, n-octyl, Methacrylates such as isopropyl, t-butyl, n-butyl, n-octyl and 2-ethylhexyl, and n-butyl acrylate and n-butyl methacrylate are preferred.

In particular, the core structure of the present invention has the structure of a triple-core rubbery polymer having a first core layer, a second core layer, and a third core layer. The first core layer is formed by polymerizing an alkyl acrylate monomer alone by including a crosslinking agent as an acrylic rubber. The second core layer and the third core layer are formed by crosslinking the alkyl acrylate monomer, the cross-linking agent and the grafting agent to the first core layer in a stepwise manner to form a first core layer, a second core layer, And has a structure in which the cross-linking density gradually increases in the order of layers, and the cross-linking density is gradually increased, thereby maximizing the impact resistance. The rubber structure is well deformed to easily deform the structure due to the morphology of the acrylic rubber when an external impact is generated.

The alkyl acrylate polymer having the triple-core structure preferably has an average particle diameter of 1,500 ANGSTROM to 4,500 ANGSTROM or less, a gel content of 80 to 95 wt.%, And a swelling index of 15 to 30. When the diameter of the alkyl acrylate polymer particle is less than 1,500 angstroms, there is a problem that the impact strength improving efficiency is lowered. When the particle diameter is more than 4,500 angstroms, the impact strength is slightly increased. However, when the graft copolymer is manufactured, An excessive amount of solidification product is generated to affect the polymerization stability, and the low-temperature impact resistance, fluidity and gloss of the final molded product may be lowered, and particularly the coloring property may be lowered.

In order to improve the coloring property of the styrene-acrylonitrile graft polymer, which is a shell layer, the core particle diameter distribution may be a combination of two kinds of bimodal or trimodal triple core rubbery polymers having different average particle diameters have. As an example, when the particle diameter distribution of the core is bimodal, it is most preferable to include two different kinds of cores having an average particle size of 1,600 to 2,000 and 2,800 to 3,500 angstroms.

The alkyl acrylate monomer is preferably contained in an amount of 30 to 100 parts by weight based on 100 parts by weight of the total weight of the styrene-based monomer and the acrylonitrile-based monomer forming the shell layer on a solid basis. When the content of the alkyl acrylate rubbery polymer is less than 30 parts by weight, the polymerization reaction proceeds more than necessary according to the increase of the graft monomer, so that it is difficult to secure the physical properties of the low temperature impact strength and high coloring property, and the occurrence of solidification product may increase. On the other hand, if it is contained in an amount exceeding 100 parts by weight, the grafting rate can not be sufficiently secured due to the reduction of the graft monomer, and the graft reaction on the inside of the core and the surface of the core proceeds unevenly, As a result, it is not easy to recover in the form of powder, which may adversely affect the surface gloss and appearance of the final molded product, and may cause problems in caking and blocking during long-term storage of the powder.

(B) shell layer (styrene-acrylonitrile copolymer)

In the present invention, a styrene-acrylonitrile-based copolymer in which a styrene-based monomer and an acrylonitrile-based monomer are graft-copolymerized with the tri-core rubbery polymer (A) forms a shell layer.

Examples of the styrene-based monomer include side-chain alkyl-substituted styrenes such as styrene,? -Ethylstyrene and? -Methylstyrene, alkyl-substituted styrenes such as p-methylstyrene and ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene And the like can be used alone or in combination. Of these, styrene may be preferably used. Examples of the acrylonitrile-based monomer include acrylonitrile and methacrylonitrile, which may be used alone or in combination. Of these, acrylonitrile can be preferably used.

The styrene-acrylonitrile-based copolymer is preferably formed by graft copolymerizing 20 to 40% by weight of a styrene-based monomer and 60 to 80% by weight of an acrylonitrile-based monomer to form a shell layer.

Hereinafter, a method for producing the ASA graft copolymer of the present invention will be described in detail. The entire contents of the ASA graft copolymer are included in the following production methods as a whole

ASA Graft  Process for producing a copolymer

Step 1 - Preparation of Tri-Core Rubbery Polymer

The tri-core rubbery polymer of the present invention is obtained by mixing (1) 25 to 40% by weight of 100% by weight of the total alkyl acrylate monomer and 0.01 to 0.2% by weight of a molecular weight modifier with respect to 100 parts by weight of the total alkyl acrylate monomer, , An emulsifier and ion-exchanged water are added and stirred to raise the temperature to 55 to 65 DEG C, and then a polymerization initiator is added to maintain the polymerization temperature at 70 to 75 DEG C to form a first core layer; ) A crosslinking agent, a grafting agent, and / or a molecular weight modifier are further added to 100 parts by weight of the total alkyl acrylate monomer in an amount of 25 to 40% by weight in 100% by weight of the total alkyl acrylate monomer, and polymerization (3) 25 to 40% by weight of 100% by weight of the total alkyl acrylate monomer, 100 to 50% by weight of a crosslinking agent, a grafting agent, and / or Jaryang modulators reulreul additional input to form a third core layer by the polymerization until the polymerization conversion rate reached 98% and the polymerization is completed through a step of preparing a core rubber polymer latex of the three.

Step 2 - Formation of Shell Layer

After the redox-based catalyst was added to the prepared tri-core rubbery polymer latex and stirred for 5 to 10 minutes, 20 to 40% by weight of the styrene-based monomer, 60 to 80% by weight of the acrylonitrile-based monomer, When the polymerization conversion rate reaches 93 to 98% at a temperature of 70 to 75 DEG C for 2 to 5 hours, the ASA graft copolymer of the present invention is cooled by forced cooling to terminate polymerization to form a shell layer of the ASA graft copolymer. Is completed.

The components used in the first and second polymerization stages will be described below.

The grafting agent may be selected from the group consisting of aryl methacrylate (AMA), triaryl isocyanurate (TAIC), triarylamine (TAA), aryl maleate (AM), diaryl fumarate (DAF) ), And the content thereof is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the total alkyl acrylate monomer.

The crosslinking agent may be selected from the group consisting of divinylbenzene, trivinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3 butanediol dimethacrylate, 1,6 hexanediol Dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, or trimethylolmethane triacrylate. The amount of the alkyl acrylate monomer is 0.01 to 100 parts by weight based on 100 parts by weight of the total alkyl acrylate monomer. 2 parts by weight.

Examples of the polymerization initiator include acetylchrohexylsulfonylperoxide, 2-2 'azobis-2,4-dimethylvaleronitrile, 2-2' azobis- (2-amidinopropane) dihydrochloride, , 2-2'-azobisisobutyronitrile, benzoyl peroxide, dimethyl-2,2'-azobisisobutylonitrile, 4,4'-azobis-4-cyanovaleric acid, cumene hydroperoxide Oxides and the like can be used, and the content thereof is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the total alkyl acrylate monomers.

The emulsifier can be used without limitation as long as it is used in conventional emulsion polymerization. Examples thereof include metal salts of potassium rosinate and sodium, metal salts of fatty acids such as sodium laureate, sodium oleate, potassium oleate and potassium stearate, sodium lauryl sulfate and potassium rosinate. Among them, potassium stearate or potassium rosinate can be used singly or in combination. The emulsifier is preferably used in an amount of 0.3 to 5 parts by weight. When the content of the emulsifier is less than 0.3 part by weight, a large amount of the coagulate in the rubbery polymer latex may be generated. When the amount of the emulsifier is more than 5 parts by weight, it may be difficult to secure physical properties such as graft rate and gas is generated on the appearance of the molded article during injection molding Can lead to problems.

As the redox catalyst used in the graft polymerization of the core and the shell layer, 0.0005 to 0.006 part by weight of ferrous sulfate, 0.01 to 0.15 part by weight of sodium pyrophosphate, and 0.05 to 0.15 part by weight of dextrose are mixedly used .

When the type of the polymerization initiator used in the first stage, the second stage and the third stage of the polymerization initiator in the polymerization initiator is out of the above-mentioned conditions, the graft copolymer of the present invention can not be produced, The graft ratio can not be sufficiently secured, the amount of unreacted monomers increases, and the problem of excess amount of the graft polymer may occur. On the other hand, when the content of the polymerization initiator is higher than the above range, there is a problem that the polymerization rate is unstable and the amount of the coagulated product is increased due to the increase of the reaction rate.

Example

The specifications of each component used in the following examples and comparative examples are as follows.

Step 1 - Formation of cores

Example 1

(N-dodecylmercaptan) was mixed with 100 parts by weight of the total butyl acrylate monomer in an amount of 30% by weight based on 100% by weight of the total alkyl acrylate monomer, and the resultant mixture was added to 3.3 parts by weight of an emulsifier, After the exchanged water was added, the temperature was raised while stirring. When the reaction temperature reached 55 to 65 占 폚, the mixture was stirred for 10 minutes while maintaining the temperature, and 0.5 part by weight of the polymerization initiator was added thereto to initiate polymerization. When the polymerization reaction was initiated and the temperature of the reaction system reached 70 to 75 캜, the internal temperature of the reactor was maintained at 70 to 75 캜 using a cooler, and the reaction was continued for 10 to 20 minutes to form a first core layer. (2) To the prepared first core layer rubbery polymer latex, 35 weight% of butyl acrylate monomer, 0.2 weight part of a crosslinking agent (triallyl isocyanurate) and a grafting agent (allyl methacrylate), and a molecular weight adjusting agent were continuously And further added to polymerize until the conversion rate reached 95% to form a second core layer. (3) To the prepared second core layer rubbery polymer latex, 35 weight% of butyl acrylate monomer, 0.2 weight part of a crosslinking agent (triallyl isocyanurate) and a grafting agent (allyl methacrylate), and a molecular weight adjusting agent were gradually added And the mixture was further added to polymerize until the polymerization conversion reached 98% to form a third core layer to prepare a triple-core rubbery polymer having an average particle diameter of 1000 Å.

Example 2-3

A core rubbery copolymer was prepared in the same manner as in Example 1 except that each component was used in the contents shown in Table 1 below.

Comparative Example 1-3

A core rubbery copolymer was prepared by the same method as in Example 1, except that each component was used in the contents shown in Table 1 below.

Step 2 - Formation of Shell Layer

Example 4

0.5 part by weight of the redox-based catalyst mixture, 0.6 part by weight of the emulsifier and 0.7 part by weight of the polymerization initiator were added to 60 parts by weight of the rubbery polymer latex of Example 1 and stirred for 5 to 10 minutes. Then, 65% by weight of the styrene- 35% by weight were continuously fed at a polymerization temperature of 70 to 75 캜 for 2 to 5 hours. When the polymerization conversion reached 93 to 98%, the ASA graft copolymer latex was prepared by forced cooling to terminate polymerization. Strength, color index and weather resistance were measured, and the results are shown in Table 3.

Examples 5-8 and Comparative Examples 4 to 11

The ASA graft copolymer latex was prepared by the same method as in Example 4, except that the components and contents described in the following Table 2 were used, and the impact strength, color index and weatherability were measured after preparing the specimen, Table 3 shows the results.

Examples 11-15 and Comparative Examples 10-17

The ASA copolymers prepared in Examples 4 to 8 and Comparative Examples 4 to 11 were compounded with a SAN copolymer and extruded / processed to obtain thermoplastic resins in the form of pellets. The extrusion was carried out using a twin-screw extruder having L / D = 29 and 45 mm in diameter, and the barrel temperature was set at 230 ° C. The pellets were dried at 80 DEG C for 2 hours, and then a specimen having a size of 9 cm x 5 cm x 0.2 cm was produced at a cylinder temperature of 240 DEG C and a mold temperature of 60 DEG C using a 6 Oz injection molding machine. The specimens were measured for impact strength, color index and weather resistance. The results are shown in Table 2.

Property evaluation method

Izod impact strength (knotched): measured according to ASTM D256.

Coloring property: The L value and the b value of the coloring property test piece were measured using CCM (Minolta). The lower the L value is, the lower the brightness and the darker the black color, the better the color pigmentation.

Weatherability: Measured according to SAE J 1960 (2000 hr, dE / db).

* Particle size distribution: 1 is unimodal, 2 is bimodal, 3 is trimodal

As a result of the experiment, it was confirmed that the tri-core rubbery copolymers of Examples 1 to 3 were made into ASA graft copolymers of Examples 11 to 15 which were prepared with unimodal, bimodal, and trimodal particle size distributions Were measured by compounding with a SAN copolymer and the physical properties were measured. As a result, it was found that the weatherability and the impact strength were excellent and the coloring property was improved as compared with Comparative Examples 10 to 17 using the double core ASA copolymer.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (26)

A core-shell structure of an acrylonitrile-styrene-acrylate (ASA) graft copolymer, wherein the core is a tri-core rubbery polymer in which alkyl acrylate monomers are sequentially polymerized, the shell is a styrene-based monomer and an acrylonitrile- Wherein the monomer is graft-copolymerized with the core to form an ASA graft copolymer.
The ASA graft copolymer according to claim 1, wherein the core has an average particle diameter of 1,500 ANGSTROM to 4,500 ANGSTROM, a gel content of 80 to 95 wt.%, And a swelling index of 15 to 30.
The ASA graft copolymer according to claim 1, wherein the tri-core rubbery polymer has a gradual increase in cross-linking density in the order of the first core layer, the second core layer, and the third core layer.
The ASA graft copolymer according to claim 1, wherein the weight ratio of the triple core to the shell is 20:80 to 80:20.
The ASA graft copolymer according to claim 1, wherein the triple core rubbery polymer has a particle size distribution of bimodal or trimodal.
The ASA graft copolymer according to claim 1, wherein the alkyl acrylate monomer is an alkyl acrylate monomer having 2 to 8 carbon atoms.
The method according to claim 1, wherein the styrenic monomer is selected from the group consisting of styrene,? -Ethylstyrene,? -Methylstyrene, p-methylstyrene, ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, Lt; RTI ID = 0.0 > ASA < / RTI > graft copolymer.
The ASA graft copolymer according to claim 1, wherein the acrylonitrile-based monomer is acrylonitrile, methacrylonitrile, or a mixture thereof.
[3] The method according to claim 1, wherein the alkyl acrylate monomer is contained in an amount of 30 to 100 parts by weight based on 100 parts by weight of the styrenic monomer and the acrylonitrile monomer forming the shell layer on a solid basis. Copolymer.
The ASA graft copolymer according to claim 1, wherein the shell is polymerized with 20 to 40% by weight of the styrene-based monomer and 60 to 80% by weight of an acrylonitrile-based monomer.
A thermoplastic resin composition comprising the ASA graft copolymer according to any one of claims 1 to 10.
An ASA resin molded article produced from the thermoplastic resin composition of claim 11.
The resin composition according to any one of claims 1 to 10, wherein the resin composition compounded with the ASA graft polymer and the SAN resin at a weight ratio of 4: 6 has an impact strength of 30 kgcm / cm (1 kg / cm 2) / 8 "knotched), and the value of? E measured according to SAE J 1960 is 3.0 or less.
Alkyl acrylate monomers to prepare a tri-core rubbery polymer latex; And
Graft copolymerizing the styrene-based monomer and the acrylonitrile-based monomer with the tri-core rubbery polymer to form a shell layer;
≪ / RTI >
The method of claim 14, wherein the step of preparing the triple-core rubbery polymer latex comprises the steps of (1) feeding an alkyl acrylate monomer into a reactor, stirring and stirring an emulsifier and ion- , Adding a polymerization initiator and maintaining the polymerization temperature at 70 to 75 캜 to form a first core layer; (2) further adding an alkyl acrylate monomer, a crosslinking agent and a grafting agent to form a second core layer; And (3) adding an alkyl acrylate monomer, a crosslinking agent and a grafting agent to form a third core layer to produce a triple-core rubbery polymer, crosslinking the first core layer, the second core layer, Wherein the density of the ASA graft copolymer is gradually increased.
16. The method according to claim 15, wherein the second core layer forming step is polymerized until the conversion rate reaches 95%, and the third core layer forming step is polymerized until the conversion rate reaches 98% By weight based on the total weight of the ASA graft copolymer.
15. The method of claim 14, wherein the shell layer is formed by adding a redox-based catalyst mixture to a triple-core rubbery polymer latex, stirring the resulting mixture for 5 to 10 minutes, and then adding the styrene-based monomer, acrylonitrile- Is continuously supplied at a polymerization temperature of 70 to 75 캜 for 2 to 5 hours and then polymerized to form a shell layer of the ASA graft copolymer.
18. The method for producing an ASA graft copolymer according to claim 17, wherein the shell layer forming step is carried out until polymerization conversion reaches 93 to 98%.
16. The method of claim 15, wherein each step of forming the core layer comprises from 25 to 40% by weight of 100% by weight of the total alkyl acrylate monomer, and wherein the forming of the second core layer and the third core layer comprises forming the alkyl acrylate monomer 100 And 0.01 to 2 parts by weight of a cross-linking agent and a grafting agent based on 100 parts by weight of the total amount of the graft copolymer.
15. The method according to claim 14, wherein the styrene-based monomer is contained in an amount of 90 to 70 parts by weight, and the acrylonitrile-based monomer is contained in an amount of 10 to 30 parts by weight.
16. The method of claim 15, wherein the grafting agent is selected from the group consisting of aryl methacrylate (AMA), triaryl isocyanurate (TAIC), triarylamine (TAA), aryl maleate (AM), diaryl fumarate (DAF) And a diarylamine (DAA). ≪ RTI ID = 0.0 > 21. < / RTI >
The method of claim 15, wherein the crosslinking agent is selected from the group consisting of divinylbenzene, trivinylbenzene, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1,3 butanediol dimethacrylate , 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, and trimethylolmethane triacrylate. The amount of the ASA graft ≪ / RTI >
16. The method according to claim 15, wherein the polymerization initiator is at least one selected from the group consisting of acetylchrohexylsulfonylperoxide, 2-2 'azobis-2,4-dimethylvaleronitrile, 2-2' azobis- (2-amidinopropane) dihydro Azobisisobutyronitrile, benzoyl peroxide, dimethyl-2,2'-azobisisobutylonitrile, and 4,4'-azobis-4-cyano Valeric acid, and valeric acid. The method for producing an ASA graft copolymer according to claim 1,
16. The method of claim 15, wherein the emulsifier is potassium stearate, potassium rosinate, or a mixture thereof.
18. The process according to claim 17, wherein the redox-based catalyst mixture comprises 0.0005 to 0.006 part by weight of ferrous sulfate, 0.01 to 0.15 part by weight of sodium pyrophosphate, and 0.05 to 0.15 part by weight of dextrose. ≪ / RTI >
25. An ASA graft copolymer prepared by the process of any one of claims 14 to 25.