KR101478027B1 - Acrylate-Styrene-Acrylonitrile Graft Copolymer Having Excellent Impact-resistance and Dyeability Property, and Method for Preparing Same - Google Patents

Abstract

The acrylonitrile-styrene-acrylate (ASA) graft copolymer according to the present invention comprises (A) a core layer comprising a polymer polymerized with an alkyl acrylate monomer having a weight average molecular weight of 200,000 to 10,000,000 g / mol and (B) ) A shell layer comprising a styrene monomer having a weight average molecular weight of 50,000 to 500,000 g / mol and a polymer polymerized with an acrylonitrile monomer, the core layer (A) comprising a first core layer formed by polymerizing an alkyl acrylate monomer, A third core layer formed by copolymerizing an alkyl acrylate monomer and a styrene monomer in a first core layer and a second core layer formed by copolymerizing an alkyl acrylate monomer and a styrene monomer in the second core layer; Is an ASA graft copolymer having a core-shell structure and is excellent in impact resistance and coloring property.

Description

TECHNICAL FIELD The present invention relates to an acrylonitrile-styrene-acrylate graft copolymer excellent in impact resistance and coloring property, and a process for producing the acrylonitrile-styrene-acrylate graft copolymer.

The present invention relates to an acrylonitrile-styrene-acrylate graft copolymer. More specifically, the present invention relates to an acrylonitrile-styrene-acrylate graft copolymer excellent in impact resistance and colorability.

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, automobile parts and general merchandise.

However, since the ABS resin contains a chemically unstable double bond in the rubber component in the resin, the rubber component can be easily aged by ultraviolet rays, so that the weather resistance and the light resistance are poor. In addition, when left outdoors for a long time, it is not suitable for outdoor use exposed to sunlight due to large discoloration and deterioration of physical properties over time.

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 extrusion processing of an ABS resin is used. However, the former method has a disadvantage in that the process is complicated and the defect rate is high, and the latter method has a disadvantage in that the production cost is not increased and satisfactory long-term weatherability is not obtained.

In order to overcome the limitation of the use of such an ABS resin, various resins known to have excellent weather resistance are used instead of ABS resin. A double acrylate-styrene-acrylonitrile resin (hereinafter referred to as ASA resin) It is the most widely used.

As the ASA resin, an acrylic graft polymer obtained by emulsion-graft-polymerizing a vinyl cyanide and an aromatic vinyl compound, and 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 controlling the physical properties and the content of the acrylic graft polymer and the vinyl cyanide-aromatic vinyl compound copolymer to be used and selectively adding a reinforcing agent having a specific role, a resin having a desired physical property can be obtained. 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, since heat resistance is indispensable for outdoor use, styrene-acrylonitrile resin, which is an alpha-methylstyrene matrix, has been conventionally used to improve the heat resistance of ASA resin, which is a weather resistant resin. However, a copolymer of a vinyl cyanide compound and an alpha-methyl styrene compound used for heat resistance has excellent heat resistance, but it causes a decrease in injection stability and deterioration of appearance characteristics due to a large amount of gas generation, The yellow color was poor in colorability.

Accordingly, the present inventors have developed an ASA graft copolymer having excellent impact resistance and colorability by controlling the core layer and shell layer structure of the ASA graft copolymer having a core-shell structure.

An object of the present invention is to provide an ASA graft copolymer excellent in impact resistance.

Another object of the present invention is to provide an ASA graft copolymer excellent in colorability.

Another object of the present invention is to provide an ASA graft copolymer excellent in fluidity.

Another object of the present invention is to provide an ASA graft copolymer excellent in heat resistance.

Another object of the present invention is to provide a process for producing an ASA graft copolymer excellent in impact resistance and coloring property.

These and other objects of the invention are all achievable by the invention which is described below.

The ASA graft copolymer according to the present invention comprises (A) a core layer comprising a polymer polymerized with an alkyl acrylate monomer having a weight average molecular weight of 200,000 to 10,000,000 g / mol and (B) a core layer having a weight average molecular weight of 50,000 to 500,000 g / mole of styrene monomer and a polymer polymerized with acrylonitrile monomer.

The ASA graft copolymer comprises 30 to 80% by weight of the core layer (A) and 20 to 70% by weight of the shell layer (B).

The core layer (A) comprises a first core layer formed by polymerizing an alkyl acrylate monomer, a second core layer formed by copolymerizing an alkyl acrylate monomer and a styrene monomer in a first core layer, and a second core layer formed by copolymerizing an alkyl acrylate monomer And a third core layer formed by copolymerizing a styrene monomer.

The core layer (A) comprises 10 to 50% by weight of the first core layer, 10 to 50% by weight of the second core layer and 10 to 80% by weight of the third core layer.

The second core layer comprises 80 to 99% by weight of an alkyl acrylate monomer and 1 to 20% by weight of a styrene monomer, and the third core layer comprises 80 to 99% by weight of an alkyl acrylate monomer and 1 to 20% by weight of a styrene monomer have.

The first core layer, the second core layer, and the third core layer may further include a cross-linking agent. The first core layer may include 0 to 0.05 wt.% (Based on 100 parts by weight of the alkyl acrylate monomer contained in the core layer And the second core layer may further include 0.01 to 1 part by weight of a crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A), and the third core layer may include the core layer A ) May further include 0.01 to 1.5 parts by weight of a crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer.

The core layer (A) has an average particle diameter of 2,000 to 5,000 Å, a gel content of 70 to 95% by weight, and a swelling index of 5 to 20.

The crosslinking density of the core layer (A) is gradually increased in the order of the first core layer, the second core layer and the third core layer, and the particle size distribution is unimodal, bimodal or trimodal, This is possible without restrictions.

The alkyl acrylate monomer is an alkyl acrylate monomer having 2 to 20 carbon atoms. Styrene monomers are styrene,? -Ethylstyrene,? -Methylstyrene, p-methylstyrene, o-t-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, and mixtures thereof. The acrylonitrile monomers are acrylonitrile, methacrylonitrile, and mixtures thereof.

The shell layer (B) is composed of 20 to 90% by weight of styrene monomer, and 10 to 80% by weight of acrylonitrile monomer.

The thermoplastic resin composition according to the present invention comprises the ASA graft copolymer, and the molded article according to the present invention is produced from a thermoplastic resin composition.

A method for producing an ASA graft copolymer having a core-shell structure according to the present invention includes the steps of: forming a first core layer by polymerizing an alkyl acrylate monomer; And copolymerizing the styrene monomer to form a second core layer; and copolymerizing the alkyl acrylate monomer and the styrene monomer to the second core layer to form a third core layer, And graft-copolymerizing the monomer and the acrylonitrile monomer with the core layer.

Hereinafter, the present invention will be described in detail.

The ASA graft copolymer according to the present invention has an effect of providing an ASA graft copolymer excellent in impact resistance, coloring property, flowability and heat resistance.

The present invention relates to an acrylonitrile-styrene-acrylate graft copolymer, and more particularly to an acrylonitrile-styrene-acrylate graft copolymer excellent in impact resistance and colorability.

ASA Graft  Copolymer

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.

In order to obtain excellent impact resistance and colorability, the present invention forms a first core layer, a second core layer and a third core layer by stepwise using a crosslinking agent and a grafting agent in an alkyl acrylate monomer, The core layer, the second core layer, and the third core layer were formed in the order of gradually increasing the cross-linking density. Thereafter, the ASA graft copolymer of the present invention was prepared by graft-polymerizing a styrene monomer and an acrylonitrile monomer to a core layer to form a shell layer of a styrene-acrylonitrile (SAN) copolymer.

The ASA graft copolymer according to the present invention comprises (A) a core layer comprising a polymer polymerized with an alkyl acrylate monomer having a weight average molecular weight of 200,000 to 10,000,000 g / mol and (B) a core layer having a weight average molecular weight of 50,000 to 500,000 g / mol and a polymer polymerized with an acrylonitrile monomer, wherein the core layer (A) comprises a first core layer formed by polymerizing an alkyl acrylate monomer, an alkyl acrylate monomer and a second core layer formed on the first core layer, A second core layer formed by copolymerizing a styrene monomer, and a third core layer formed by copolymerizing an alkyl acrylate monomer and a styrene monomer in a second core layer, wherein the core-shell structure is a core-shell structure .

The ASA graft copolymer comprises 30 to 80% by weight of the core layer (A) and 20 to 70% by weight of the shell layer (B).

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

(A) the core layer

The core layer (A) of the present invention comprises a polymer polymerized with an alkyl acrylate monomer having a weight average molecular weight of 200,000 to 10,000,000 g / mol, and has a structure of a triple core.

The core layer (A) comprises 10 to 50% by weight of the first core layer, 10 to 50% by weight of the second core layer and 10 to 80% by weight of the third core layer. When the content ranges of the first core layer to the third core layer are included in the ranges as described above, the impact resistance is excellent.

The first core layer is formed by polymerizing an alkyl acrylate monomer as an acrylic rubber. The second core layer is formed by copolymerizing the alkyl acrylate monomer and the styrene monomer together with the crosslinking agent in the first core layer and the third core layer is formed by copolymerizing the alkyl acrylate monomer and the styrene monomer together with the crosslinking agent in the second core layer do.

The second core layer comprises 80 to 99% by weight of an alkyl acrylate monomer and 1 to 20% by weight of a styrene monomer, and the third core layer comprises 80 to 99% by weight of an alkyl acrylate monomer and 1 to 20% by weight of a styrene monomer have. When the styrene content is less than the lower limit value, the coloring property is lowered, and when the styrene content is higher than the upper limit value, the impact resistance is lowered.

The first core layer, the second core layer and the third core layer may further comprise a crosslinking agent. The first core layer may further comprise 0 to 0.05 parts by weight, preferably 0 to 0.03 part by weight, of the crosslinking agent relative to 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A) The alkyl acrylate monomers may be polymerized alone without a cross-linking agent. The second core layer may further include 0.01 to 1 part by weight, preferably 0.01 to 0.5 part by weight, of a crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A). The third core layer may further include 0.01 to 1.5 parts by weight, preferably 0.01 to 1 part by weight, of a crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A). The content of the crosslinking agent contained in the third core layer is larger than the content of the crosslinking agent contained in the second core layer. When the content of the cross-linking agent exceeds the upper limit value, the effect of impact reinforcement is reduced.

The alkyl acrylate monomers include alkyl acrylates having 2 to 20 carbon atoms such as methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, t-butyl acrylate, n-butyl acrylate, n-octyl acrylate, Acrylate monomers such as methyl acrylate, ethyl acrylate, ethyl acrylate, ethyl acrylate, ethyl acrylate and ethylhexyl acrylate; and monomers such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, Methacrylate, and 2-ethylhexyl methacrylate. These monomers may be used singly or in combination. Of these, n-butyl acrylate or n-butyl methacrylate can be preferably used.

Styrene monomers include side chain alkyl substituted styrenes such as styrene, alpha -ethylstyrene and alpha -methylstyrene and alkyl substituted styrenes such as p-methylstyrene and ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene and the like These may be used alone or in combination. Of these, styrene can be preferably used.

The crosslinking agent may be at least one selected from the group consisting of aryl methacrylate, triarylisocyanurate, triarylamine, aryl maleate, diaryl fumarate, diarylamine, divinylbenzene, trivinylbenzene, ethylene glycol dimethacrylate, diethylene glycol di Methacrylate, triethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethyl And methane triacrylate, which may be used alone or in combination.

The core layer (A) has a structure in which the cross-linking density gradually increases in the order of the first core layer, the second core layer and the third core layer. The cross-linking density gradually increases toward the outside of the core layer (A), thereby having a structure in which the impact resistance is maximized. Due to the morphology of the acrylic rubber, the rubber structure can be well deformed so that the structure is easily deformed when an external impact is generated.

The first core layer uses a polymer that is polymerized with an alkyl acrylate monomer having a weight average molecular weight of 200,000 to 10,000,000 g / mol. Since the polymer itself polymerized with an alkyl acrylate monomer has a low glass transition temperature and it is difficult to produce core particles, in order to give excellent impact resistance in the case of the first core polymerizing only the alkyl acrylate monomer alone, the weight average molecular weight The use of a polymer polymerized with a high alkyl acrylate monomer imparts rubber properties to the first core layer. When the weight average molecular weight of the polymer polymerized with the alkyl acrylate monomer is less than 200,000 g / mol, core particles are not produced. When the molecular weight exceeds 10,000,000 g / mol, polymerization of the polymer polymerized with the alkyl acrylate monomer is difficult and the polymerization time is long .

The second core layer and the third core layer can maintain the shape of the core layer (A) by lowering the strain caused by the alkyl acrylate monomer by copolymerizing the alkyl acrylate monomer and the minimum styrene monomer.

The core layer (A) preferably has an average particle diameter of 2,000 to 5,000 Å, a gel content of 70 to 95% by weight, and a swelling index of 5 to 20. When the average particle diameter of the core layer (A) is less than 2,000 ANGSTROM, the impact resistance is lowered. When the core layer (A) is more than 5,000 ANGSTROM, the impact strength is somewhat increased, but the mechanical stability is lowered during the production of the graft copolymer, The polymerization stability is affected, and the fluidity, glossiness and coloring property of the final molded product may be deteriorated.

The core layer (A) may be a triple-core rubbery polymer having a unimodal particle size distribution or may be a styrene-acrylonitrile graft polymerized in the shell layer (B) in the core layer (A) A bimodal or trimodal triple core rubbery polymer having a different particle diameter may be mixed and used.

(B) shell layer

In the present invention, a styrene-acrylonitrile-based copolymer (hereinafter referred to as 'SAN') in which a styrene monomer and an acrylonitrile monomer are graft-copolymerized with a core layer (A) forms a shell layer (B).

The SAN has a weight average molecular weight of 50,000 to 500,000 g / mol, preferably 100,000 to 300,000 g / mol. By using a SAN having a high weight average molecular weight in the shell layer (B), the strain caused by the alkyl acrylate monomer is lowered to maintain the ASA copolymer in the form of an impact modifier.

Styrene monomers include side chain alkyl substituted styrenes such as styrene, alpha -ethylstyrene and alpha -methylstyrene and alkyl substituted styrenes such as p-methylstyrene and ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene and the like , Which may be used alone or in combination. Of these, styrene may be preferably used.

Examples of the acrylonitrile monomer include acrylonitrile and methacrylonitrile, and these 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 90% by weight of a styrene monomer and 10 to 80% by weight of an acrylonitrile-based monomer to form a shell layer (B).

Hereinafter, a method for producing the ASA graft copolymer of the present invention will be described in detail.

ASA Graft  Process for producing a copolymer

Stage 1 - The core layer (A)  Produce

The method for producing the core layer (A) of the present invention comprises the steps of: (a) adding 10 to 50% by weight of an alkyl acrylate to 100% by weight of the entire alkyl acrylate monomer in the core layer (A) Exchanged water is added and stirred to raise the reaction 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; (b) (A) from 25 to 45% by weight of an alkyl acrylate based on 100% by weight of the total alkyl acrylate monomer, from 0.01 to 70% by weight of a styrene monomer based on 100% by weight of the alkyl acrylate monomer used in the second core layer, ) 0.01 to 1 part by weight of a crosslinking agent is added to 100 parts by weight of the whole alkyl acrylate monomer, and then a crosslinking agent, an emulsifier, an electrolyte, and ion exchange water are added thereto and stirred to adjust the reaction temperature to 55 to 65 ° C (C) a step of forming a core layer (A) on the entirety of the alkyl acrylate monomer by adding a polymerization initiator to the alkyl acrylate 0.01 to 70 parts by weight of a styrene monomer based on 100 parts by weight of the alkyl acrylate monomer used in the third core layer, and 0.01 to 1.5 parts by weight of a crosslinking agent based on 100 parts by weight of the entire alkyl acrylate monomer (A) The polymerization temperature is maintained at 70 to 75 占 폚, and the polymerization temperature is maintained at 70 to 75 占 폚. After the temperature is raised to 55 to 65 占 폚, Thereby forming a third core layer.

Step 2 - In the shell layer (B)  formation

30 to 80 parts by weight of the core layer (A) are charged with an emulsifying agent and ion-exchanged water, and the temperature is raised while stirring. Then, when the internal temperature of the reactor reaches 50 to 60 캜, a water-soluble polymerization initiator is added. Thereafter, 20 to 70 parts by weight of a monomer mixture containing 20 to 90% by weight of a styrene monomer and 10 to 80% by weight of an acrylonitrile monomer are mixed and stirred with a molecular weight adjuster, and then a core layer (A) into which a water- For 1 to 5 hours continuously to form the shell layer (B), thereby completing the ASA graft copolymer of the present invention.

The redox catalyst or the pyrolysis catalyst may be further used in forming the core layer (A) and the shell layer (B). As the redox-based catalyst, it is preferable to mix 0.0005 to 0.006 parts by weight of ferrous sulfate, 0.01 to 0.15 parts by weight of sodium pyrophosphate, and 0.05 to 0.15 parts by weight of dextrose. As the thermal decomposition catalyst, the above water-soluble polymerization initiator can be used.

The components used in the polymerization are described as follows.

The crosslinking agent may be at least one selected from the group consisting of aryl methacrylate, triarylisocyanurate, triarylamine, aryl maleate, diaryl fumarate, diarylamine, divinylbenzene, trivinylbenzene, ethylene glycol dimethacrylate, diethylene glycol di Methacrylate, triethylene glycol dimethacrylate, 1,3-butanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethyl And methane triacrylate. The first core layer may further comprise 0 to 0.05 parts by weight of a crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A), and the second core layer may include an alkyl acrylate The third core layer may further include 0.01 to 1.5 parts by weight of a crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A). The crosslinking agent may further include 0.01 to 1 part by weight of a crosslinking agent based on 100 parts by weight of the monomer. have.

The emulsifier can be used without limitation as long as it is used in ordinary 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 based on 100 parts by weight of the total alkyl acrylate monomers used in the core layer (A). If the content of the emulsifier is less than 0.3 part by weight, a large amount of coagulation in the core layer (A) may occur. If 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 the like.

The polymerization initiator may be a commonly used water-soluble polymerization initiator such as potassium persulfate, sodium persulfate, ammonium persulfate, and silver persulfate. The amount of the water-soluble polymerization initiator may be 0.2 to 100 parts by weight of the total alkyl acrylate monomer used in the core layer (A) To 1 part by weight. When the content of the polymerization initiator is less than 0.2 parts by weight, the desired grafting rate can not be achieved, unreacted monomers are increased, and a problem of excessive formation of the graft polymer may occur. On the other hand, when the content of the polymerization initiator is more than 1 part by weight, there is a problem that the polymerization system becomes unstable due to an increase in the reaction rate and the amount of the coagulum is increased.

The contents of the alkyl acrylate monomers, styrene monomers, acrylonitrile monomers and the like can all be applied to the production method of the ASA graft copolymer and are omitted in order to avoid duplication.

Thermoplastic resin composition

The present invention provides a thermoplastic resin composition comprising the ASA graft copolymer.

The thermoplastic resin composition according to the present invention can be produced by a known method for producing a resin composition. For example, the components of the present invention and other additives may be simultaneously mixed and then melt-extruded in an extruder to produce pellets or chips.

The content of the alkyl acrylate monomer, the styrene monomer, the acrylonitrile monomer and the like can be all applied to the thermoplastic resin composition and is omitted in order to avoid duplication.

Molded product

The present invention provides a molded article produced from the thermoplastic resin composition.

There is no particular limitation on the method of molding the molded article, and extrusion, injection molding or casting molding methods can be applied. Such molding can be easily carried out by a person having ordinary skill in the art to which the present invention belongs.

The molded article of the present invention has an impact strength of 7 to 15 kgf · cm / cm measured at a temperature of 23 ° C. and a thickness of 1/4 inch according to ASTM 256, a temperature of 23 ° C. and a viscosity of 1/8 " inch < / RTI > thickness is 20 to 50 kgf · cm / cm.

The molded product was placed on a test piece having a melt flow index of 18 to 23 g / 10 min measured at a temperature of 200 캜 and a load of 5 kg according to ASTM D 1238, a thickness of 3 to 6.4 mm and an area of 10 mm x 10 mm or more in accordance with ASTM D1525 The Vicat softening point measured when the needle is placed on the specimen with a depth of 1 mm while applying a load is 94 to 97 占 폚.

The molded product has an L value of 23 to 25 and a b value of -1.55 to -3.75 as measured by CCM of Minolta.

The content of the alkyl acrylate monomer, the styrene monomer, the acrylonitrile monomer, and the like may all be applied to a molded article and is omitted in order to avoid duplication.

Example

The specifications of each component used in the following Production Examples and Comparative Production Examples are as follows.

Manufacturing example  One

Stage 1 - The core layer (A)  formation

10 parts by weight of butyl acrylate was added to the reactor, and 0.5 part by weight of the emulsifier, 0.1 part by weight of the electrolyte and 150 parts by weight of ion-exchanged water were added to 100 parts by weight of the butylacrylate and stirred. After the temperature was raised, a polymerization initiator was added and the polymerization temperature was maintained at 60 캜 to form a first core layer. To the produced first core layer, 45 weight% of butyl acrylate and 0.2 weight part of crosslinking agent to 100 weight part of the butylacrylate monomer were added to the reactor. At this time, 0.5 part by weight of the emulsifier and 0.1 part by weight of the electrolyte were charged and stirred to raise the reaction temperature to 70 DEG C, and then the polymerization initiator was added to maintain the polymerization temperature at 70 DEG C to form the second core layer. To the produced second core layer, 45 weight% of butyl acrylate and 0.6 weight part of crosslinking agent to 100 weight part of the butylacrylate monomer were added to the reactor. At this time, 0.5 part by weight of the emulsifier and 0.1 part by weight of the electrolyte were charged and stirred to raise the reaction temperature to 70 DEG C, and then the polymerization initiator was added to maintain the polymerization temperature at 70 DEG C to form the third core layer.

Step 2 - In the shell layer (B)  formation

50 parts by weight of the prepared core layer (A) was charged with 0.5 part by weight of an emulsifier and 50 parts by weight of ion-exchanged water, and the temperature was raised while stirring. Then, when the internal temperature of the reactor reached 70 캜, 0.1 part by weight of a water- Then, 50 parts by weight of a monomer mixture containing 70% by weight of a styrene monomer and 30% by weight of an acrylonitrile monomer was mixed with 0.01 part by weight of a molecular weight modifier and stirred. Then, the core layer (A) To form a shell layer (B), whereby the ASA graft copolymer of the present invention was completed.

Manufacturing example  2 to 4

ASA copolymer was prepared by the same production method as Production Example 1 with the contents shown in Table 1 below.

Comparative Manufacturing Example  1 to 4

The cross-linking agent was added during the production of the first core layer and the ASA copolymer was prepared in the same manner as in Production Example 1 with the contents shown in Table 1 below.

Comparative Manufacturing Example  5

An ASA copolymer was prepared in the same manner as in Production Example 1, except that styrene monomer was added only to the second core layer.

In Table 1 below, the amounts of butyl acrylate in the first to third core layers are expressed as% by weight based on 100% by weight of the total butyl acrylate in the core layer, and TAIC and styrene in the first to third core layers are Styrene and acrylonitrile in the shell layer are expressed as parts by weight based on 100% by weight of styrene and acrylonitrile. will be.

Manufacturing example Comparative Manufacturing Example One 2 3 4 One 2 3 4 5 Core layer The first core layer Butyl acrylate 10 20 30 30 10 10 20 30 10 TAIC - - - 0.02 0.1 0.2 0.2 0.2 - The second core layer Butyl acrylate 45 40 35 35 45 45 40 35 45 Styrene 5 5 5 5 - - - - 5 TAIC 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 The third core layer Butyl acrylate 45 40 35 35 45 45 40 35 45 Styrene 5 5 5 5 - - - - - TAIC 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 Shell layer Styrene 70 70 70 70 70 70 70 70 70 Acrylonitrile 30 30 30 30 30 30 30 30 30

* TAIC: triallyl isocyanurate

Example  1-3 and Comparative Example  1-5

40 parts by weight of the ASA copolymer prepared in Production Examples 1 to 4 and Comparative Production Examples 1 to 5 was compounded with 60 parts by weight of a copolymer containing 70% by weight of a styrene monomer and 30% by weight of an acrylonitrile monomer, And then a thermoplastic resin in the form of a pellet was obtained. 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. After the specimens were prepared, the impact strength, melt flow index, heat resistance and coloring degree were measured and the results are shown in Table 2.

(1) Izod impact strength (knotched, kgf · cm / cm): Measured according to ASTM 256 at a temperature of 23 ° C and a thickness of 1/4 "and 1/8 inch.

(2) Melt flow index (MI, g / 10 min): Measured according to ASTM D1238 at a temperature of 200 캜 and a load of 5 kg.

(3) Heat resistance (Vicat softening point, 占 폚): A needle was placed on a test piece having a thickness of 3 to 6.4 mm and an area of 10 mm 占 10 mm or more in accordance with ASTM D1525.

(4) Coloration degree: L value, a value and b value were measured using CCM of Minolta Co.

Example Comparative Example One 2 3 4 One 2 3 4 5 Impact strength 1/4 " 8.5 9.0 10.2 9.5 6.4 6.5 6.9 6.2 8.5 1/8 " 20.5 29.0 39.7 34.2 16.5 15.2 15.2 16.1 25.4 Melt flow index 19.7 20.9 21.3 21.1 15.2 13.7 16.2 17.4 19.9 Heat resistance 94.5 95.0 95.9 95.8 95.2 95.2 95.3 95.4 95.6 Coloration degree L value 23.28 23.20 23.41 23.45 24.85 24.90 24.92 24.68 23.90 a value 0.10 0.11 -0.04 -0.01 0.10 0.12 0.13 -0.58 0.10 b value -2.36 -2.51 -2.45 -2.35 -1.52 -1.56 -1.77 -1.75 -2.20

In Examples 1 to 3 using a styrene monomer for the second core layer and the third core layer without using a crosslinking agent in the production of the first core layer, a crosslinking agent was used in the production of the first core layer, The impact strength and fluidity are superior to those of Comparative Examples 1 to 4 in which no styrene monomer is used in the core layer. In addition, in Example 4 using the crosslinking agent in the content range of the present invention even when using the crosslinking agent in the production of the first core layer, the impact strength and fluidity great.

In Comparative Example 5 using the styrene monomer only in the second core layer, the degree of discoloration was lower than that in Example 1 in which the styrene monomer was used for the second core layer and the third core layer.

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 (20)

(A) a core layer comprising a polymer polymerized with an alkyl acrylate monomer having a weight average molecular weight of 200,000 to 10,000,000 g / mol; And
(B) a shell layer comprising a styrene monomer having a weight average molecular weight of 50,000 to 500,000 g / mol and a polymer polymerized with an acrylonitrile monomer;
/ RTI >
Wherein the core layer (A) comprises a first core layer formed by polymerizing an alkyl acrylate monomer, a second core layer formed by copolymerizing the alkyl acrylate monomer and the styrene monomer in the first core layer, and a second core layer formed by copolymerizing alkyl Styrene-acrylate (ASA) graft copolymer of core-shell structure, characterized in that it is a triple core rubbery polymer comprising a third core layer formed by copolymerizing an acrylate monomer and a styrene monomer.
The ASA graft copolymer according to claim 1, comprising 30 to 80% by weight of the core layer (A) and 20 to 70% by weight of the shell layer (B).
The method of claim 1, wherein the core layer (A) comprises 10 to 50 wt% of the first core layer, 25 to 45 wt% of the second core layer, and 25 to 45 wt% of the third core layer By weight based on the weight of the graft copolymer.
The method of claim 1, wherein the second core layer comprises 80 to 99% by weight alkyl acrylate monomer and 1 to 20% by weight styrene monomer, the third core layer comprises 80 to 99% by weight alkyl acrylate monomer, 1 to 20% by weight of monomers.
The ASA graft copolymer according to claim 1, wherein the first core layer, the second core layer and the third core layer further comprise a crosslinking agent.
6. The method of claim 5, wherein the first core layer further comprises 0 to 0.05 parts by weight of the crosslinking agent relative to 100 parts by weight of the alkyl acrylate monomer contained in the core layer (A) The first core layer further comprises 0.01 to 1 part by weight of the crosslinking agent based on 100 parts by weight of the alkyl acrylate monomer contained in the layer (A), and the third core layer comprises 100 parts by weight of the alkyl acrylate monomer And 0.01 to 1.5 parts by weight of the cross-linking agent relative to 100 parts by weight of the ASA graft copolymer.
The ASA graft copolymer according to claim 1, wherein the core layer (A) has an average particle diameter of 2,000 to 5,000 Å, a gel content of 70 to 95% by weight, and a swelling index of 5 to 20.
The ASA graft copolymer according to claim 1, wherein the core layer (A) is gradually increased in cross-linking density in the order of the first core layer, the second core layer, and the third core layer.
The method according to claim 1, wherein the core layer (A) has a unimodal particle size distribution. Characterized in that it is bimodal or trimodal. ≪ RTI ID = 0.0 > 21. < / RTI >
The ASA graft copolymer according to claim 1, wherein the alkyl acrylate monomer is an alkyl acrylate monomer having 2 to 20 carbon atoms.
The method according to claim 1, wherein the styrene monomer is selected from the group consisting of styrene,? -Ethylstyrene,? -Methylstyrene, p-methylstyrene, ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene, ≪ RTI ID = 0.0 > ASA < / RTI > graft copolymer.
The ASA graft copolymer according to claim 1, wherein the acrylonitrile monomer is at least one selected from the group consisting of acrylonitrile, methacrylonitrile, and mixtures thereof.
The ASA graft copolymer according to claim 1, wherein the shell layer (B) comprises 20 to 90% by weight of a styrene monomer, and 10 to 80% by weight of an acrylonitrile monomer.
14. A thermoplastic resin composition comprising an ASA graft copolymer according to any one of claims 1 to 13.
A molded article produced from the thermoplastic resin composition of claim 14.
The molded article according to claim 15, wherein the molded article has an impact strength of 7 to 15 kgf · cm / cm measured at a temperature of 23 ° C. and a thickness of 1/4 inch according to ASTM 256, a temperature of 23 ° C. according to ASTM 256, Wherein the impact strength measured at a thickness of 1/8 inch is 20 to 50 kgf cm / cm.
The molded article according to claim 15, wherein the molded article has a melt flow index of 18 to 23 g / 10 min measured at a temperature of 200 캜 and a load of 5 kg according to ASTM D1238.
The molded article as set forth in claim 15, wherein the molded article has a Vicat softening point measured at a depth of 1 mm when a needle is placed on a test piece having a thickness of 3 to 6.4 mm and an area of 10 mm x 10 mm or more in accordance with ASTM D1525, Lt; RTI ID = 0.0 > 97 C. < / RTI >
The molded article according to claim 15, wherein the L value measured using CCM of Minolta Co. is 23 to 25, and the b value is -1.55 to -3.75.
In a method for producing an ASA graft copolymer having a core-shell structure,
The method of producing a core layer comprises polymerizing an alkyl acrylate monomer to form a first core layer; Copolymerizing the alkyl acrylate monomer and the styrene monomer with the first core layer to form a second core layer; And copolymerizing the alkyl acrylate monomer and the styrene monomer with the second core layer to form a third core layer,
Wherein the shell layer comprises graft-copolymerizing a styrene monomer and an acrylonitrile monomer with the core layer.