KR102001483B1 - Acrylic graft copolymer, process for the same, and thermoplastic resin composition - Google Patents

Abstract

A rubber polymer comprising a core comprising an alkyl (meth) acrylate-aromatic vinyl compound copolymer, and a core comprising an alkyl (meth) acrylate based polymer; And a shell layer formed by grafting an aromatic vinyl compound-unsaturated nitrile compound copolymer on the rubbery polymer, wherein the core is an acrylic graft copolymer containing at least two seeds, a process for producing the acrylic graft copolymer, A thermoplastic resin composition comprising a copolymer is provided.

Description

Acrylic graft copolymer, a process for producing the same, and a thermoplastic resin composition containing the same. {Acrylic graft copolymer, process for same, and thermoplastic resin composition}

The present invention relates to an acrylic graft copolymer. More specifically, the present invention relates to an acrylic graft copolymer excellent in impact resistance, coloring property, and process stability, a method for producing the same, and a thermoplastic resin composition containing the same.

The acrylonitrile-butadiene-styrene copolymer (ABS) resin containing an acrylonitrile-butadiene-styrene graft copolymer (g-ABS) in which styrene and acrylonitrile monomers are graft-copolymerized with butadiene rubber Impact strength, mechanical strength, surface characteristics and processability, and is widely used in electric / electronic products, automobile parts and office equipment.

However, since the ABS resin contains a chemically unstable double bond in the rubber component, the rubber component can easily aged by ultraviolet rays, so that the weather resistance and 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 improve this, a method of adding a weathering stabilizer during extrusion processing is used, but its effect is not so great and it still has properties that are vulnerable to ultraviolet rays. Therefore, in recent years, various methods have been proposed to overcome such problems. In particular, a method of using a chemically stable acrylic rubber instead of butadiene rubber, a method of using a rubbery polymer obtained by polymerizing butadiene and an acrylic polymerizable monomer, and the like have been widely used. A double acrylate-styrene-acrylonitrile resin (hereinafter referred to as 'ASA resin') is the most widely used.

As the ASA resin, an acrylic graft copolymer obtained by emulsion-graft-polymerizing an unsaturated nitrile compound and an aromatic vinyl compound and an unsaturated nitrile-aromatic vinyl copolymer obtained by copolymerizing an unsaturated nitrile compound and an aromatic vinyl compound are mixed and extruded . At this time, by adjusting the physical properties and the content of the acrylic graft copolymer and the unsaturated nitrile-aromatic vinyl compound copolymer to be used, and optionally adding a reinforcing agent having a specific role, a resin having desired properties can be obtained. The ASA resin thus produced is excellent in weatherability, chemical resistance and thermal stability since it does not have chemically unstable double bonds, and thus is widely used for electric / electronic products, automobile parts, construction and sports goods used for outdoor use. Or impact resistance at room temperature, application to electric / electronic parts, agricultural equipment, automobile interior materials and parts has been extremely limited. In order to meet such demands, research on weatherable resins having a small change in physical properties and excellent colorability according to the temperature conditions of use has been required.

Accordingly, the present inventors have come to develop an acrylic graft copolymer having excellent impact resistance, coloring property, and process stability by controlling the structure of a core layer and a shell layer of an acrylic graft copolymer having a core-shell structure.

One embodiment provides an acrylic graft copolymer having excellent impact resistance, colorability, and process stability.

Another embodiment provides a method of making the acrylic graft copolymer.

Another embodiment provides a thermoplastic resin composition comprising the acrylic graft copolymer.

According to one embodiment, a rubbery polymer comprising a core of an alkyl (meth) acrylate-aromatic vinyl compound copolymer and a core of an alkyl (meth) acrylate based polymer; And a shell layer formed by grafting an aromatic vinyl compound-unsaturated nitrile compound copolymer to the rubbery polymer, wherein the core comprises an acrylic graft copolymer containing at least two seeds.

The seeds may each have an average particle diameter of 50 nm to 80 nm.

The seed may contain an alkyl (meth) acrylate compound and an aromatic vinyl compound in a weight ratio of 1: 3 to 3: 1.

The rubbery polymer may have an average particle size of 150 nm to 200 nm, a gel content of 80% to 95% by weight, and a swelling index of 10 to 20.

The rubbery polymer may comprise from 15% to 30% by weight of the seed and from 70% to 85% by weight of the core, based on the total amount of rubbery polymer.

The acrylic graft copolymer may include 30% to 60% by weight of the rubbery polymer and 40% to 70% by weight of the shell layer, based on the total amount of the acrylic graft copolymer.

The shell layer may comprise 50% to 70% by weight of an aromatic vinyl compound and 30% to 50% by weight of an unsaturated nitrile compound.

The graft ratio of the acrylic graft copolymer may be 30% to 70%.

According to another embodiment of the present invention, there is provided a method for producing a rubbery polymer, comprising: preparing a rubbery polymer having a core containing at least two seeds; and grafting the aromatic vinyl compound-unsaturated nitrile compound copolymer to the rubbery polymer, The step of preparing the polymer is carried out by adding a crosslinking agent, an emulsifying agent and a solvent to a mixture of an alkyl (meth) acrylate compound and an aromatic vinyl compound, raising the temperature to 50 to 60 ° C, And the temperature is raised to 70 ° C to 80 ° C to form a seed; A second step of injecting an initiator, an emulsifier and a reducing agent into the same reactor in which the first step has been performed, and then dropping an alkyl (meth) acrylate compound and a crosslinking agent; And a third step of introducing an alkyl (meth) acrylate compound and a cross-linking agent into the same reactor in which the second step is performed, after the addition of a reducing agent and an initiator, wherein the grafting step includes the step of injecting an emulsifier into the rubber- To raise the temperature to 50 to 60 DEG C, and then to introduce the initiator; And heating the aromatic vinyl compound and the unsaturated nitrile compound to 70 占 폚 to 80 占 폚 with the dropwise addition of the initiator after the introduction of the initiator. The present invention also provides a method for producing the acrylic graft copolymer.

The initiator may include potassium persulfate, diisopropylbenzene hydroperoxide, or a combination thereof.

The reducing agent may include sodium formaldehyde sulfoxylate.

The emulsifying agent may include potassium rosinate, dioctyl sodium succinate, a mixture of palmitic acid and stearic acid, or combinations thereof.

The redox catalyst may comprise ferrous sulfate, sodium ethylenediaminetetraacetate, or a combination thereof.

The crosslinking agent may comprise triallyl isocyanate, allyl methacrylate or a combination thereof.

In the first step, the mixture of the alkyl (meth) acrylate compound and the aromatic vinyl compound may be mixed with the alkyl (meth) acrylate compound and the aromatic vinyl compound in a weight ratio of 1: 3 to 3: 1.

The pH after introducing the initiator in the first step may be 4.8 to 6.0.

In the second step, the electrolyte may be further charged together with the emulsifier and the reducing agent.

The electrolyte may include potassium carbonate, calcium carbonate, sodium pyrophosphate, potassium chloride, sodium chloride, or combinations thereof.

According to another embodiment of the present invention, there is provided a thermoplastic resin composition comprising the above-mentioned acrylic graft copolymer.

The thermoplastic resin composition may further include at least one additive selected from the group consisting of a heat stabilizer, a release agent, a dispersant, a weathering stabilizer, an inorganic filler, a dye / pigment, and a flame retardant.

A thermoplastic resin composition comprising an acrylic graft copolymer and an acrylic graft copolymer excellent in impact resistance, colorability, and process stability can be realized.

1 is a transmission electron microscope (TEM) photograph of a thermoplastic resin composition containing an ASA graft copolymer of Example 1. Fig.
2 is a transmission electron microscope (TEM) photograph of the thermoplastic resin composition containing the ASA graft copolymer of Comparative Example 2. Fig.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

In the present specification, "copolymerization" means block copolymerization or random copolymerization, and "copolymer" means block copolymer or random copolymer.

&Quot; (Meth) acrylic acid "refers to both" acrylic acid "and" methacrylic acid " "It means both are possible.

One embodiment provides an acrylic graft copolymer having excellent impact resistance, colorability, and process stability.

Hereinafter, each component will be described in more detail.

Acrylic Graft  Copolymer

The acrylic graft copolymer is obtained by graft-polymerizing an acrylic rubber-like polymer with a monomer mixture comprising an aromatic vinyl compound and an unsaturated nitrile compound, and is well known to those skilled in the art.

The present invention forms seeds and cores in order to improve impact resistance, coloring property, and process stability, and in particular, the core is formed to contain at least two seeds. At this time, the seed and core formation proceeds in a one-pot reaction, and the pH is changed stepwise during the reaction, and a point reaction is induced together with the association reaction of the seed, so that a core including the associated seed can be formed. As the reaction proceeds in a one-pot rather than a two-pot, the pH can be easily changed during the reaction so that two or more, for example two to five, seeds can be associated in the core. When two or more seeds are present in combination in the core, they have a high refractive index, so that impact resistance and coloring property can be improved.

Thereafter, the acrylic graft copolymer of the present invention was prepared by graft-polymerizing an aromatic vinyl monomer and an unsaturated nitrile monomer to a core layer to form a shell layer of an aromatic vinyl-unsaturated nitrile copolymer.

The acrylic graft copolymer according to the present invention comprises a rubbery polymer comprising a core composed of an alkyl (meth) acrylate-aromatic vinyl compound copolymer and a core composed of an alkyl (meth) acrylate based polymer; And a shell layer formed by grafting an aromatic vinyl compound-unsaturated nitrile compound copolymer on the rubbery polymer, wherein the core contains at least two seeds.

The seeds in the acrylic graft copolymer may independently have an average particle size of 50 nm to 80 nm. When the average particle diameter of the seed is within the above range, it is easy to couple two or more seeds in the core during the reaction, and the average particle diameter of the core can be controlled. For example, the rubber polymer composed of the seed and the core containing the seed may have an average particle diameter of 150 nm to 200 nm.

The reason why the average particle diameter of the rubbery polymer is important is that the reflectivity changes when the particle diameter changes, and the color change occurs in the final thermoplastic resin composition containing the same. Therefore, in order to obtain a thermoplastic resin composition of uniform mass production quality, More important than anything else.

By thus having a uniform average particle diameter of the rubbery polymer, process stability can be improved.

The seed may contain an alkyl (meth) acrylate compound and an aromatic vinyl compound in a weight ratio of 1: 3 to 3: 1. If the content of the alkyl (meth) acrylate compound exceeds 3 times the content of the aromatic vinyl compound, the coloring property may be deteriorated. If the content of the aromatic vinyl compound exceeds 3 times the content of the alkyl (meth) The impact resistance may be deteriorated.

The alkyl (meth) acrylate compound may be at least one selected from the group consisting of methyl acrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate, t-butyl acrylate, n-butyl acrylate, n- Acrylate compounds such as octyl acrylate and 2-ethylhexyl acrylate, and acrylate compounds such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, t-butyl methacrylate, n- Methacrylate compounds such as methacrylate, n-octyl methacrylate, and 2-ethylhexyl methacrylate. These may be used singly or in combination. Of these, n-butyl acrylate or n-butyl methacrylate can be preferably used.

The aromatic vinyl compound may be at least one selected from the group consisting of a side chain alkyl-substituted styrene such as styrene,? -Ethylstyrene,? -Methylstyrene and the like and an alkyl-substituted styrene such as p-methylstyrene and ot-butylstyrene, bromostyrene, chlorostyrene, trichlorostyrene and the like These can be used alone or in combination. Of these, styrene can be preferably used.

The rubbery polymer may comprise from 15% to 30% by weight of the seed and from 70% to 85% by weight of the core.

The acrylic graft copolymer may comprise 30 wt% to 50 wt% of the rubbery polymer and 50 wt% to 70 wt% of the shell layer.

The shell layer may comprise 50% to 70% by weight of an aromatic vinyl compound and 30% to 50% by weight of an unsaturated nitrile compound.

The shell layer is formed by grafting an aromatic vinyl compound-unsaturated nitrile compound copolymer to a rubbery polymer.

The aromatic vinyl compound-unsaturated nitrile compound copolymer has a weight average molecular weight of 50,000 g / mol to 500,000 g / mol, preferably 100,000 g / mol to 300,000 g / mol. By using an aromatic vinyl compound-unsaturated nitrile compound copolymer having a high weight average molecular weight in the shell layer, the degree of deformation due to the rubbery polymer is lowered, thereby maintaining the acrylic graft copolymer in the form of an impact modifier.

The aromatic vinyl compound may be a styrene-based monomer, and the styrene-based monomer may include a side chain alkyl-substituted styrene such as styrene,? -Ethylstyrene,? -Methylstyrene, and the like, an alkyl-substituted styrene such as p- Bromostyrene, chlorostyrene, trichlorostyrene and the like, which may be used alone or in combination. Of these, styrene may be preferably used.

Examples of the unsaturated nitrile compound include acrylonitrile, methacrylonitrile, and fumaronitrile, which may be used alone or in combination. Of these, acrylonitrile can be preferably used.

The graft ratio of the acrylic graft copolymer may be 30% to 70%.

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

Acrylic Graft  Process for producing a copolymer

The acrylic graft copolymer of the present invention is produced by preparing a rubbery polymer having a core containing at least two seeds, and grafting the aromatic vinyl compound-unsaturated nitrile compound copolymer to the rubbery polymer.

The step of preparing the rubbery polymer may be carried out by adding a crosslinking agent, an emulsifier and a solvent to a mixture of an alkyl (meth) acrylate compound and an aromatic vinyl compound, raising the temperature to 50 to 60 ° C, And an initiator, and heating the mixture to 70 to 80 캜 to form a seed; A second step of injecting an initiator, an emulsifier and a reducing agent into the same reactor in which the first step has been performed, and then dropping an alkyl (meth) acrylate compound and a crosslinking agent; And a third step of introducing an alkyl (meth) acrylate compound and a cross-linking agent after the reducing agent and the initiator are charged into the same reactor in which the second step is performed.

The grafting may be performed by injecting an emulsifying agent into the rubbery polymer, raising the temperature to 50 to 60 ° C, and then introducing an initiator; And heating the aromatic vinyl compound and the unsaturated nitrile compound to 70 占 폚 to 80 占 폚 with the dropwise addition of the initiator.

The types of the alkyl (meth) acrylate compound and the aromatic vinyl compound are as described above.

The initiator may include potassium persulfate, diisopropylbenzene hydroperoxide, or a combination thereof.

The reducing agent may include sodium formaldehyde sulfoxylate.

The emulsifying agent may include potassium rosinate, dioctyl sodium succinate, a mixture of palmitic acid and stearic acid, or a combination thereof, but any conventional emulsion polymerization method may be used without limitation.

The redox catalyst may comprise ferrous sulfate, sodium ethylenediaminetetraacetate, or a combination thereof.

The crosslinking agent may comprise triallyl isocyanate, allyl methacrylate or a combination thereof.

The electrolyte may include potassium carbonate, calcium carbonate, sodium pyrophosphate, potassium chloride, sodium chloride, or combinations thereof.

Step 1

The mixture of the alkyl (meth) acrylate compound and the aromatic vinyl compound may be a mixture of an alkyl (meth) acrylate compound and an aromatic vinyl compound in a weight ratio of 1: 3 to 3: 1.

The crosslinking agent may be added to the mixture in an amount of 1 part by weight to 5 parts by weight, for example, 1 part by weight to 4 parts by weight based on 100 parts by weight of the mixture. If the content of the crosslinking agent is less than 1 part by weight based on 100 parts by weight of the mixture, the crosslinking effect is lowered. If the amount of the crosslinking agent exceeds 5 parts by weight based on 100 parts by weight of the mixture, the effect of impact reinforcement may be deteriorated.

An emulsifier and a solvent (ion-exchanged water; distilled water) are added together with the crosslinking agent to form a monomer mixture (alkyl (meth) acrylate compound and aromatic vinyl compound) The temperature is raised to 60 占 폚.

After the temperature is raised to the above temperature (50 to 60 ° C), stirring can be performed while maintaining the temperature for about 10 minutes.

Subsequently, a catalyst is then added for the redox reaction and an initiator is added thereto to initiate a polymerization reaction, and the temperature is raised to 70 ° C to 80 ° C to form a seed.

The initiator may be added in an amount of 0.2 part by weight to 1.0 part by weight based on 100 parts by weight of the monomer mixture (alkyl (meth) acrylate compound and aromatic vinyl compound). If the content of the initiator is less than 0.2 parts by weight, the desired grafting rate can not be achieved, unreacted monomers are increased, and the problem of excessive formation of the graft polymer may occur. On the other hand, when the content of the initiator is more than 1.0 part by weight, the polymerization rate is unstable due to an increase in the reaction rate, and the amount of the coagulum is increased.

The pH is lowered by the decomposition of the introduced initiator (pH 4.8 to 6.0), and thus the alkyl (meth) acrylate compound and the aromatic vinyl compound may be dispersed in a spherical random copolymer.

On the other hand, when the initiator is applied, degassing through bubbling with nitrogen gas (N ₂ gas) can be preceded. This is to prevent initiation inhibition by active oxygen.

After the temperature is raised to the above temperature (70 ° C to 80 ° C), the temperature can be maintained for about 10 minutes to 20 minutes.

Step 2

An initiator, an emulsifier and a reducing agent are added to the same reactor in which the first step is performed, and then an alkyl (meth) acrylate compound and a crosslinking agent are added dropwise.

The electrolyte may be further charged together with the emulsifier and the reducing agent. The electrolyte may be contained in an amount of 1.2 to 2.0 parts by weight based on 100 parts by weight of the alkyl (meth) acrylate compound. When the electrolyte is further added, several seeds, which are random copolymers of an alkyl (meth) acrylate compound and an aromatic vinyl compound, are more easily assembled.

Step 3

After the alkyl (meth) acrylate compound and the cross-linking agent are added dropwise, a reducing agent and an initiator are further added, and an alkyl (meth) acrylate compound and a cross-linking agent are further added.

The crosslinking agent may be included in an amount of 0.5 to 1.0 part by weight based on 100 parts by weight of the alkyl (meth) acrylate compound.

After the third step, the initiator may be further added at a temperature immediately after the end of the third step, and the reaction may be further performed for about 30 minutes to 60 minutes. In this case, the polymerization rate can be further increased. At this time, the initiator may be at least one selected from the group consisting of chlorodisopropylbenzene hydroperoxide, ditbutylisopropylbenzene hydroperoxide, para-cumene hydroperoxide, chloroisopropylbenzene peroxide, diisopro- teyl cumyl hydroperoxide, etc. But is not limited thereto.

Graft  step

An emulsifier is added to the rubbery polymer synthesized according to the above-mentioned production method, and the temperature is raised to 50 to 60 DEG C, and then an initiator is added. Ion exchanged water (distilled water) may be further added together with the emulsifier.

After the temperature is raised to the above-mentioned temperature (50 ° C to 60 ° C), an initiator is added.

After the introduction of the initiator, the aromatic vinyl compound and the unsaturated nitrile compound are heated to 70 ° C to 80 ° C for 2 hours to 5 hours while being dropwise added. At this time, a molecular weight regulator can be further added.

Thereafter, the temperature (70 ° C to 80 ° C) is maintained for 20 minutes to 120 minutes, and the polymerization is terminated to finally form an acrylic graft copolymer.

Thermoplastic resin composition

The present invention provides a thermoplastic resin composition comprising the acrylic 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.

For example, 40 parts by weight of the above-mentioned acrylic graft copolymer 15 parts by weight; And 60 to 85 parts by weight of an unsaturated nitrile compound-aromatic vinyl compound copolymer.

In particular, the unsaturated nitrile compound-aromatic vinyl compound copolymer can be prepared by copolymerizing a mixture containing 20 to 45% by weight of an unsaturated nitrile compound and 80 to 55% by weight of an aromatic vinyl compound.

The thermoplastic resin composition may further include at least one additive selected from the group consisting of a heat stabilizer, a releasing agent, a dispersing agent, a weathering stabilizer, an inorganic filler, a dye / pigment, and a flame retardant.

The content of the alkyl (meth) acrylate compound, the aromatic vinyl compound, the unsaturated nitrile compound, and the like can be all applied to the thermoplastic resin composition and is omitted in order to avoid duplication.

(Example)

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. However, the following examples and comparative examples are for illustrative purposes only and are not intended to limit the present invention.

Example  One

5 parts by weight of styrene and 15 parts by weight of n-butyl acrylate were added to 20 parts by weight of the total monomer, 0.7 part by weight of a crosslinking agent was added, and then an emulsifier and ion-exchanged water were added. When the temperature of the reaction system reached 50 ° C to 60 ° C, the mixture was stirred for 10 minutes while maintaining the temperature. 0.002 parts by weight of ferrous sulfate and 0.04 part by weight of sodium ethylenediaminetetraacetate were added as a redox catalyst, And 0.4 part by weight of persulfate were added in portions to initiate the polymerization reaction. At the same time as the reaction was initiated, the temperature of the reaction system was elevated. The internal temperature of the reactor was maintained at 70 ° C, and the reaction was continued for 10 minutes to 20 minutes to synthesize a seed having a polymerization conversion of 95% or more. At this time, the average grain size (Z-average) of the seeds measured using a dynamic light scattering grain size analyzer was 60 nm. (Step 1)

After the seed synthesis, it was allowed to stand for 10 minutes. Subsequently, an emulsifier and a reducing agent were added, and then an initiator was added thereto. Then, 40 parts by weight of n-butyl acrylate and 0.3 part by weight of a crosslinking agent were added dropwise so that the polymerization conversion rate reached 95% or more (second step)

Then, a reducing agent and an initiator were added, 40 parts by weight of n-butyl acrylate and 0.3 part by weight of a crosslinking agent were added, and when the polymerization conversion reached 98%, the polymerization of the rubbery polymer was completed. (Third step)

50 parts by weight of the rubber polymer, 50 parts by weight of an emulsifier, a molecular weight regulator and ion-exchanged water were added and stirred for 5 minutes to 10 minutes, and then the mixture was heated to 50 to 60 DEG C, and an initiator was added thereto. And 33 wt% of acrylonitrile, and the molecular weight regulator were heated to 70 DEG C to 80 DEG C over a period of 2 hours to 5 hours. Thereafter, the polymerization was terminated by maintaining the temperature at 70 to 80 캜 for 20 to 120 minutes, thereby obtaining an acrylic resin having an average particle size (Z-average) of 180 nm measured using a dynamic light scattering particle size analyzer Styrene-acrylonitrile (ASA) graft copolymer was prepared.

Example  2

In the second step, the same procedure as in Example 1 was carried out except that 0.6 parts by weight of the electrolyte was further added together with the reducing agent and the emulsifying agent. The average particle diameter of the seed was 65 nm, and the average particle diameter of the ASA graft copolymer was 173 nm.

Example  3

In the second step, the same procedure as in Example 2 was carried out, except that it was allowed to stand for 40 minutes after the seed synthesis. The average particle diameter of the seed was 63 nm, and the average particle diameter of the ASA graft copolymer was 176 nm.

Example  4

In the first step, the same procedure as in Example 2 was carried out except that the internal temperature of the reactor was maintained at 75 캜 after the initiator was charged. The average particle diameter of the seed was 64 nm, and the average particle diameter of the ASA graft copolymer was 172 nm.

Example  5

In the second step, the same procedure as in Example 1 was carried out except that 0.8 parts by weight of the electrolyte was further added together with the reducing agent and the emulsifying agent. The average particle diameter of the seed was 63 nm, and the average particle diameter of the ASA graft copolymer was 197 nm.

Comparative Example  One

The procedure of Example 1 was repeated except that 1.0 part by weight of a crosslinking agent was used in the first step and no redox catalyst was used. The average particle diameter of the seed was 81 nm, and the average particle diameter of the ASA graft copolymer was 147 nm.

Comparative Example  2

The same procedure as in Comparative Example 1 was carried out except that the second step was left for 40 minutes after the seed synthesis. The average particle diameter of the seed was 95 nm, and the average particle diameter of the ASA graft copolymer was 168 nm.

evaluation

40 parts by weight of the ASA graft copolymer prepared in Examples 1 to 5 and Comparative Example 1 and Comparative Example 2 were mixed with styrene-acrylic acid copolymerized from a mixture containing 70% by weight of styrene and 30% by weight of acrylonitrile And 60 parts by weight of a rhenitrile copolymer (SAN), followed by extrusion to obtain a thermoplastic resin composition in the form of a pellet. The extrusion was performed using a biaxial extruder having L / D = 29 and a diameter of 45 mm, and the barrel temperature was set at 230 ° C. The pellets were dried at 80 DEG C for 2 hours, and then subjected to a 6 oz injection molding machine at a cylinder temperature of 240 DEG C and a mold temperature of 60 DEG C to prepare test specimens. The impact strength, flow index, tensile strength, flexural strength and flexural modulus of the specimens were measured, and the results are shown in Table 1 below.

(1) Izod Impact Strength (Unit: kgf · cm / cm): Measured by making a notch on a 1/8 inch thick Izod sample according to the evaluation method described in ASTM D256.

(2) Flow Index (Unit: g / 10 min): Measured at 300 ° C and 5 kg according to the evaluation method specified in ASTM D1238.

(3) Tensile strength (unit: kgf / cm ² ): The tensile strength of a 1/8 inch thick specimen was measured at a pulling rate of 5 mm / min according to the evaluation method specified in ASTM D638.

(4) Flexural Strength and Flexural Modulus (Unit: kgf / cm ² ): The flexural modulus and flexural strength of a 1/4 inch thick specimen were measured at a bending speed of 2.8 mm / min according to the evaluation method specified in ASTM D790 Respectively.

division Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Izod impact strength 48.9 48.6 48.5 48.8 47.9 35.1 38.3 Flow index 5.0 5.1 5.1 5.0 5.2 3.4 3.2 The tensile strength 430 430 430 430 440 440 430 Flexural strength 580 580 590 590 600 600 590 Flexural modulus 17,450 17,460 17,470 17,550 17,700 17,900 17,430

As can be seen from the above Table 1, the thermoplastic resin compositions comprising the ASA graft copolymers of Examples 1 to 5 according to the present invention contain the ASA graft copolymer of Comparative Example 1 and Comparative Example 2 It can be confirmed that it exhibits excellent impact resistance and fluidity as compared with the thermoplastic resin composition.

On the other hand, as shown in the transmission electron microscope (TEM) photographs of FIGS. 1 and 2, only one seed (black portion) was observed in the ASA graft copolymer core of Comparative Example 2 (FIG. 2) In Example 1 (Fig. 1) according to the invention, it is confirmed that at least two seeds are observed within the ASA graft copolymer core.

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 (22)

A rubber polymer comprising a core comprising an alkyl (meth) acrylate-aromatic vinyl compound copolymer, and a core comprising an alkyl (meth) acrylate based polymer; And
And a shell layer formed by grafting an aromatic vinyl compound-unsaturated nitrile compound copolymer to the rubbery polymer,
The core comprising at least two seeds,
The seeds each have an average particle diameter of 50 nm to 80 nm,
Wherein the seed comprises an alkyl (meth) acrylate compound and an aromatic vinyl compound in a weight ratio of 1: 1 to 3: 1.
delete delete The method according to claim 1,
Wherein the rubbery polymer has an average particle size of 150 nm to 200 nm, a gel content of 80 to 95 wt%, and a swelling index of 10 to 20.
The method according to claim 1,
Wherein the rubbery polymer comprises from 15% to 30% by weight of the seed and from 70% to 85% by weight of the core.
The method according to claim 1,
Wherein the acrylic graft copolymer comprises 30 wt% to 60 wt% of the rubbery polymer and 40 wt% to 70 wt% of the shell layer.
The method according to claim 1,
Wherein the shell layer comprises 50% to 70% by weight of an aromatic vinyl compound and 30% to 50% by weight of an unsaturated nitrile compound.
The method according to claim 1,
The graft ratio of the acrylic graft copolymer is 30% to 70%.
Preparing a rubbery polymer having a core containing at least two seeds, and grafting the aromatic vinyl compound-unsaturated nitrile compound copolymer to the rubbery polymer,
Wherein the step of preparing the rubbery polymer comprises:
A crosslinking agent, an emulsifying agent and a solvent are added to a mixture of an alkyl (meth) acrylate compound and an aromatic vinyl compound in a weight ratio of 1: 1 to 3: 1 and then the mixture is heated to 50 to 60 ° C, And an initiator, and raising the temperature to 70 占 폚 to 80 占 폚 to form a seed having an average particle diameter of 50 nm to 80 nm;
A second step of injecting an initiator, an emulsifier and a reducing agent into the same reactor in which the first step has been performed, and then dropping an alkyl (meth) acrylate compound and a crosslinking agent; And
And a third step of introducing an alkyl (meth) acrylate compound and a cross-linking agent after the reducing agent and the initiator are charged into the same reactor in which the second step is performed,
Wherein the grafting comprises:
Adding an emulsifying agent to the rubbery polymer, raising the temperature to 50 to 60 DEG C, and then introducing an initiator; And
Heating the aromatic vinyl compound and the unsaturated nitrile compound to 70 占 폚 to 80 占 폚 while the initiator is being added dropwise
Based on the weight of the graft copolymer.
10. The method of claim 9,
Wherein the initiator is selected from the group consisting of potassium persulfate, diisopropylbenzene hydroperoxide, or a combination thereof.
10. The method of claim 9,
Wherein the reducing agent comprises sodium formaldehyde sulfoxylate.
10. The method of claim 9,
Wherein the emulsifier comprises a mixture of potassium rosinate, dioctyl sodium succinate, palmitic acid and stearic acid, or a combination thereof.
10. The method of claim 9,
Wherein the redox catalyst comprises ferrous sulfate, ethylenediaminetetraacetic acid sodium salt or a combination thereof.
10. The method of claim 9,
Wherein the crosslinking agent comprises triallyl isocyanate, allyl methacrylate or a combination thereof.
delete 10. The method of claim 9,
In the second step,
Wherein the electrolyte is further charged together with the emulsifier and the reducing agent.
17. The method of claim 16,
Wherein the electrolyte comprises potassium carbonate, calcium carbonate, sodium pyrophosphate, potassium chloride, sodium chloride, or a combination thereof.
delete 10. The method of claim 9,
Wherein the rubbery polymer has an average particle diameter of 150 nm to 200 nm.
10. The method of claim 9,
Wherein the pH after the introduction of the initiator in the first step is 4.8 to 6.0.
9. A thermoplastic resin composition comprising the acrylic graft copolymer according to any one of claims 1 to 8.
22. The method of claim 21,
Wherein the thermoplastic resin composition further comprises at least one additive selected from the group consisting of a heat stabilizer, a releasing agent, a dispersing agent, a weathering stabilizer, an inorganic filler, a dye / pigment and a flame retardant.

Images