KR20140085261A - Expandable resin composition, method for preparing the same and foam using the same - Google Patents

Abstract

A foam resin composition according to the present invention includes: an aromatic vinyl-based resin; a rubber-modified vinyl-based graft copolymer; and a foam agent. The foam resin composition has excellent foaming properties, high compression strength and low conductivity. The rubber-modified vinyl-based graft copolymer is copolymerized by an aromatic vinyl-based monomer and a monomer mixture including a cyanate vinyl-based monomer.

Description

TECHNICAL FIELD [0001] The present invention relates to a foamable resin composition, a method for producing the same, and a foam using the foamable resin composition,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamable resin composition, a method for producing the same, and a foam using the same. More specifically, the present invention relates to a foamable resin composition excellent in foamability, excellent in compressive strength after foaming, and low in thermal conductivity, a method for producing the same, and a foam using the same.

BACKGROUND OF THE INVENTION [0002] Foamed resins, particularly polystyrene foamed resins, are excellent in molding processability, heat insulation, buffering properties, and warmth, and the foams (expanded molded articles) are widely used as packaging materials for consumer products, agricultural and marine products boxes, and house insulation materials. In recent years, there has been an increasing demand for foams having better heat insulating properties for the purpose of energy saving and the like. As a method for improving the heat insulating property, a heat insulating material (heat insulating property improving material) such as graphite, carbon black, metal oxide, A method of introducing it into a foam has been studied.

As a method for introducing the heat insulating material into the foam, styrene is polymerized in an aqueous suspension in the presence of graphite particles, which is one of the heat insulating materials, and a foaming agent is added before, during, or after the polymerization, in Korean Patent No. 10-0492199 Discloses a method of producing a foamable styrene polymer containing graphite particles (polymerization step 1). In Korean Patent No. 10-0703823, carbon particles are mixed with a styrene resin to prepare a pellet, Discloses a method of producing foamed polystyrene by extrusion (two-step method). European Patent EP 0072536 discloses a method of producing a foamed product by extrusion foaming by introducing an insulating material such as graphite or carbon black together with an olefin resin together with a foaming agent Method (extrusion single-step method) has been disclosed, and in addition, the surface of foamed polystyrene expanded particles or the fired The there is disclosed a method of coating or embedding the heat insulating material improves the polystyrene particles (coating method).

In addition, there is a size and distribution of fine cells formed in the foaming process as a factor greatly affecting the performance of the foam. The size of the cell is small and the distribution is uniform, which is advantageous for foam performance such as mechanical properties. In order to improve such cell quality (size, distribution, etc.), generally, high crystalline polyethylene wax is used as a nucleating agent in the cell formation process.

In the case of the extrusion one-step process in which the foaming agent and the heat insulating property improving material are mixed with the resin in the extrusion process and the foamed resin in the form of micropellets is produced by using an underwater pelletizing system, It is easy to inject a large amount of heat insulating material, and the process is simple and is widely used commercially.

However, the above-mentioned extrusion single-step method is incapable of uniformly dispersing and stabilizing the foaming agent in the foaming resin during the production process and time-hardening is absolutely insufficient as compared with the above-mentioned one-stage polymerization and extrusion double- The foamability of the foamable resin is lowered and the cells of the foamed body are relatively large and uneven, resulting in a problem that physical properties such as compressive strength are deteriorated. In order to solve this problem, an inorganic nucleating agent such as calcium carbonate is used. However, since it is difficult to ensure sufficient dispersibility in the extrusion process, the content of the nucleating agent and the foaming agent in the expandable resin particles (micropellets) The distribution of the foaming agent is not uniform, and the cell size between the foam itself (foamed lip) itself and the foam is still non-uniform.

An object of the present invention is to provide a foamable resin composition having excellent foamability, excellent compression strength of a foam, and low thermal conductivity, a process for producing the same, and a foam using the same.

These and other objects of the present invention can be achieved by the present invention which is described in detail.

One aspect of the present invention relates to a foamable resin composition. Wherein the foamable resin composition comprises an aromatic vinyl resin; Rubber-modified vinyl-based graft copolymer; And a foaming agent.

In an embodiment, the rubber-modified vinyl-based graft copolymer may be one obtained by graft-copolymerizing a mixture of a monomer containing an aromatic vinyl monomer and a vinyl cyan monomer with a rubbery polymer.

Preferably, the average particle size (Z-average) of the rubbery polymer may be 0.2 to 0.35 탆.

Preferably, the gel content of the rubbery polymer may be from 70 to 90% by weight.

In an embodiment, the aromatic vinyl resin may be a resin obtained by polymerizing a monomer containing at least one of styrene, -methylstyrene, vinyltoluene, and chlorostyrene.

In an embodiment, the foaming agent may include at least one hydrocarbon compound and fluorohydrocarbons.

In an embodiment, the content of the rubber-modified vinyl-based graft copolymer is 0.1 to 10 parts by weight based on 100 parts by weight of the aromatic vinyl resin, and the content of the blowing agent is 100 parts by weight, 2 to 10 parts by weight.

In an embodiment, the foamable resin composition may further include a heat insulating material.

Preferably, the adiabatic material may include at least one of graphite, carbon black, carbon nanotubes, halloysite, hydrolytic bentonite, and metallic aluminum powder.

Preferably, the content of the heat insulating material may be 0.5 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin.

In an embodiment, when the foamable resin composition is heated for 5 minutes using steam at a pressure of 0.2 kg / cm < ² >, the expansion ratio may be 70 to 130 times.

Another aspect of the present invention relates to a method for producing the foamable resin composition. The method for producing the foamable resin composition comprises mixing an aromatic vinyl resin and a rubber-modified vinyl-based graft copolymer to form a mixed composition; Then, the foaming agent is injected into the mixed composition and extruded; The method comprising the steps of:

In an embodiment, the mixed composition may further comprise a heat insulating material.

Another aspect of the invention relates to foams. In one embodiment, the foam comprises an aromatic vinyl-based resin; And a rubber-modified vinyl-based graft copolymer.

In an embodiment, the foam may further comprise a heat insulating material.

In embodiments, the number of days to the thermal conductivity of the foam according to KS L 9016, 20 ± 1.5 kg / m density and 300 mm of the ³ × 300 mm × a specimen based on having a 50 mm size 0.030 to 0.033 W / m * K have.

In an embodiment, the compressive strength of the foam may be 8 to 12 N / cm ² on a specimen having a size of 50 mm x 50 mm x 50 mm, according to KS M ISO 844.

In another embodiment, the foam has a structure in which a dispersed phase containing a rubber-modified vinyl-based graft copolymer is dispersed in a continuous phase containing an aromatic vinyl resin, and the average cell size is 100 to 250 탆.

In another embodiment, the foam is formed by foaming the foamable resin composition.

The present invention particularly relates to a foamable resin composition excellent in foaming property, excellent in compressive strength after foaming and low in thermal conductivity even when it is manufactured by applying the one-stage extrusion method, a method for producing the foamed resin composition, and a foamed article using the same .

Hereinafter, the present invention will be described in detail.

The foamable resin composition according to the present invention comprises an aromatic vinyl-based resin; Rubber-modified vinyl-based graft copolymer; And a foaming agent.

(A) an aromatic vinyl resin

As the aromatic vinyl resin used in the present invention, any conventional aromatic vinyl resin used in the foamable resin composition (foamable resin particle) can be used without limitation, and examples thereof include styrene,? -Methylstyrene, vinyltoluene, But are not limited to, styrene resins such as general-purpose polystyrene (GPPS) and high-impact polystyrene resin (HIPS) resins obtained by polymerizing a monomer mixture containing at least one kind of monomer such as styrene.

The weight average molecular weight of the aromatic vinyl resin may be, for example, 120,000 to 400,000 g / mol, preferably 150,000 to 350,000 g / mol. The foamability and strength can be maintained within the above range.

(B) a rubber-modified vinyl-based graft copolymer

The rubber-modified vinyl-based graft copolymer used in the present invention serves as a cell controlling agent (nucleating agent) of a foam, and is obtained by copolymerizing a monomer mixture comprising an aromatic vinyl monomer and a vinyl cyanide monomer Is a graft copolymer of a graft copolymerized core-shell structure, and if necessary, a monomer capable of imparting processability and heat resistance can be further copolymerized.

The average particle size (Z-average) of the rubbery polymer may be, for example, 0.2 to 0.35 mu m, preferably 0.25 to 0.3 mu m, and the gel content may be 70 to 90 wt%, preferably 75 to 85 wt% . In the above range, the rubber-modified vinyl-based graft copolymer is uniformly dispersed in the aromatic vinyl-based resin, and a foam having excellent properties such as compressive strength and low thermal conductivity can be obtained.

Specific examples of the rubbery polymer include diene rubbers such as polybutadiene, poly (styrene-butadiene) and poly (acrylonitrile-butadiene) and saturated rubbers hydrogenated with the diene rubbers, isoprene rubber, polybutylacrylic acid Acrylic rubber, ethylene-propylene-diene monomer terpolymer (EPDM), and the like. Of these, a diene rubber is preferable, and a butadiene rubber is more preferable. The content of the rubbery polymer may be 40 to 70% by weight based on the total weight of the rubber-modified vinyl-based graft copolymer.

The aromatic vinyl-based monomer may be graft-copolymerized with the rubbery copolymer. Examples of the aromatic vinyl monomer include styrene,? -Methylstyrene,? -Methylstyrene, p-methylstyrene, pt-butylstyrene, , Monochlorostyrene, dichlorostyrene, dibromostyrene, vinylnaphthalene, and the like, but the present invention is not limited thereto. Of these, styrene is preferable. The content of the aromatic vinyl-based monomer may be 10 to 15% by weight based on the total weight of the rubber-modified vinyl-based graft copolymer.

Examples of the vinyl cyanide monomer include acrylonitrile, methacrylonitrile, and ethacrylonitrile. These monomers may be used singly or in combination of two or more. However, the present invention is not limited thereto. The content of the vinyl cyanide monomer may be 35 to 40% by weight based on the total weight of the rubber-modified vinyl-based graft copolymer.

Examples of the monomer for imparting the above processability and heat resistance include, but are not limited to, alkyl (meth) acrylate, (meth) acrylic acid, maleic anhydride and N-substituted maleimide.

Specific examples of the alkyl (meth) acrylate include alkyl (meth) acrylates having 1 to 12 carbon atoms, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate , Methacrylic acid esters such as phenyl methacrylate, phenoxyethyl methacrylate and benzyl methacrylate, and acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and 2-ethylhexyl acrylate Esters may be used, but are not limited thereto. These may be used alone or in admixture of two or more, preferably methyl methacrylate.

The content of the monomer for imparting workability and heat resistance may be 0 to 15% by weight, preferably 0.1 to 10% by weight, based on the total weight of the rubber-modified vinyl-based graft copolymer. The workability and heat resistance can be imparted without deteriorating the other properties within the above range.

Preferred examples of the rubber-modified vinyl-based graft copolymer include acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS), methyl methacrylate-acrylonitrile-butadiene-styrene graft copolymer Copolymer resin (g-MABS), and the like, and more preferably g-ABS can be used.

The content of the rubber-modified vinyl-based graft copolymer is 0.1 to 10 parts by weight, preferably 0.2 to 5.0 parts by weight, based on 100 parts by weight of the aromatic vinyl resin. In the above range, the rubber-modified vinyl-based graft copolymer is uniformly dispersed in the aromatic vinyl-based resin, and a foam having excellent properties such as compressive strength and low thermal conductivity can be obtained.

(C) foaming agent

As the foaming agent to be used in the present invention, a foaming agent used in a conventional foamable resin composition may be used. For example, hydrocarbon such as propane, butane, isobutane, normal pentane, isopentane, cyclopentane, hexane, compound; Hydrofluorocarbons such as hydrogen fluoride carbon (HCFC) such as HCFC-142b and HCFC-123, hydrogen fluoride (HFC) such as HFC-123, and mixtures thereof; And mixtures thereof, or a mixture of two or more thereof.

The content of the foaming agent is 2 to 10 parts by weight, preferably 3 to 8 parts by weight, based on 100 parts by weight of the aromatic vinyl resin. Within the above range, the foaming agent and the rubber-modified vinyl-based graft copolymer are uniformly dispersed in the aromatic vinyl-based resin, and a foam having excellent physical properties such as compressive strength and low thermal conductivity can be obtained.

The foamable resin composition according to the present invention may further include a heat insulating material in order to lower the thermal conductivity of the foam.

As the heat insulating material, a typical heat insulating material used in a foamable resin composition (foamable resin particle) can be used without limitation. Examples of the heat insulating material include graphite, carbon black, carbon nanotubes, halloysite, hydrolytic bentonite, May be used singly or in combination of two or more. The heat insulating material may have various shapes such as a spherical shape, a tubular shape, and the like, and the average particle size may be 100 nm to 10 탆, but is not limited thereto.

When the heat insulating material is used, the content thereof may be 0.5 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin. A foam having a low thermal conductivity can be obtained without lowering the physical properties in the above range.

The foamable resin composition according to the present invention may further contain conventional additives such as foam stabilizers, compatibilizers, surfactants, gas barrier resins, dispersants, antiblocking agents and flame retardants, if necessary have. For example, the above-mentioned foaming aid facilitates foaming and molding of the foamable composite resin particles, and a conventional foaming aid can be used. For example, a foaming aid such as toluene, cyclohexane, and ethylbenzene can be used have.

When the additive is used, the content may be 0.01 to 10 parts by weight based on 100 parts by weight of the foamable resin composition, but is not limited thereto.

The method for producing a foamable resin composition according to the present invention comprises mixing the aromatic vinyl resin and the rubber-modified vinyl-based graft copolymer in the above-mentioned amounts to form a mixed composition, injecting the foamed composition in the above- Extrusion step (extrusion one-step method).

In an embodiment, the mixed composition may further comprise the adiabatic material.

There is no particular limitation on the extruder used in the extrusion, but in order to obtain a desired grade, the diameter of the die plate hole may be 0.3 to 2 mm, preferably 0.5 to 1.2 mm, for example. The temperature of the melt kneading and extruder may be 135 to 230 캜, preferably 150 to 200 캜. Further, the temperature of the die plate may be 170 to 350 占 폚, preferably 190 to 300 占 폚. Within the above range, the foaming agent and the rubber-modified vinyl-based graft copolymer are uniformly dispersed in the aromatic vinyl-based resin, and a foam having excellent physical properties such as compressive strength and low thermal conductivity can be obtained.

In an embodiment, the foamable resin composition may be pelletized by an underwater cutting method during extrusion.

The above manufacturing method can be easily performed by a person having ordinary skill in the art to which the present invention belongs.

In a specific example, when the expandable polystyrene type resin beads are heated for 5 minutes with steam at a pressure of 0.2 kg / cm ² using a time booster (manufacturer: Daikin), the expansion ratio May be 70 to 130 times.

In one embodiment, the foam according to the present invention comprises the aromatic vinyl resin and the rubber-modified vinyl-based graft copolymer, and may further include the heat insulating material, if necessary.

In another embodiment, it is preferable that the resin composition has a structure in which a dispersed phase containing the rubber-modified vinyl-based graft copolymer is dispersed in a continuous phase containing the aromatic vinyl resin and has an average cell size of 100 to 250 탆, And may further include the heat insulating material.

In another embodiment, the foam may be formed by foaming the foamable resin composition.

Typically the foamable resin composition to the non-foam by fusing the airtight mold filling (introduction), and, for example, the foamable resin composition by using a hot air or steam at a pressure of 0.1 to 3 kgf / cm ² in a mold Can be manufactured. For example, the foamable resin composition to be introduced into the mold may be preliminarily foamed at a predetermined (volume) density, for example, 15 to 35 kg / m ³ by heating to a softening point or higher.

The foam may be easily manufactured by a person having ordinary skill in the art to which the present invention belongs.

In embodiments, the thermal conductivity of the foam according to KS L 9016, 20 ± 1.5 kg / m 3 density, and 300 mm × 300 mm × 50 mm size as with specimen standards, 0.030 to 0.033 W / m and K, And preferably 0.0310 to 0.0325 W / mK.

The compressive strength of the foam may be from 8 to 12 N / cm ² , preferably from 9 to 11 N / cm ² , on the basis of a specimen having a size of 50 mm x 50 mm x 50 mm, according to KS M ISO 844 .

In addition, the foam may have an average cell size of 100 to 250 탆 measured by using an optical microscope at a magnification of 200 by cutting the cross section of the foam.

Hereinafter, the present invention will be described in more detail by way of examples, but these examples are for illustrative purposes only and should not be construed as limiting the present invention.

Example

Example  One

1 part by weight of acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS, manufactured by Cheil Industries, Inc., product name: CHT) was added to 100 parts by weight of GPPS pellets (manufactured by FORMOSA CHEMICALS & FIBER CORPORATION, And 5 parts by weight of graphite having an average particle size of 6 占 퐉 (manufactured by TIMCAL Co., Ltd., product name: S-249) as an adiabatic and heat insulating material were mixed to prepare a mixed composition. A pentane mixture gas (45% isopentane, 55% A mini-pellet (foamable resin composition) having an average size of 1.2 mm was prepared by a twin-screw extruder equipped with a nozzle capable of injecting a mixed gas and an underwater pelletizing system having a die plate hole diameter of 1.0 mm . Here, the temperature of the mixed composition and the pentane mixture gas (final resin melt) was 180 ° C, the water temperature of the underwater pelletizer was 60 ° C, and the amount of the pentane mixed gas was 6.5 By weight.

Next, the obtained expandable resin composition was prepared pre-expanded beads by pre-expanded with steam of 0.2 kgf / cm ² pressure, density, using a vapor of from 0.2 to 1 kgf / cm ² pressure is 20 ± 1.5 ㎏ / m < ³ > (expansion ratio of 50 + 4 times) in a mold.

Example  2

Except that 0.5 part by weight of the acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS, trade name: Cheil Industries, CHT) was used in place of the acrylonitrile-butadiene-styrene graft copolymer resin .

Example  3

Except that 2 parts by weight of the above acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS, manufactured by Cheil Industries, Inc., product name: CHT) was used and the foamable resin composition and the foam .

Comparative Example  One

Except that the acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS, trade name: Cheil Industries, CHT, product name) was not used in the preparation of the foamable resin composition and the foam Respectively.

Comparative Example  2

Except that 1 part by weight of polyethylene wax (trade name: POLYWAX 1000, manufactured by Bakerhughes, Inc.) was used instead of the acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS manufactured by Cheil Industries, A foamable resin composition and a foamed product were prepared in the same manner as in Example 1 above.

Comparative Example  3

Except that 0.5 part by weight of polyethylene wax (manufactured by Bakerhughes, product name: POLYWAX 1000) was used in place of the above acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS manufactured by Cheil Industries, A foamable resin composition and a foamed product were prepared in the same manner as in Example 1 above.

Comparative Example  4

1 part by weight of calcium carbonate (manufacturer: OMYA KOREA Co., Ltd., product name: KRISTON-SS) was used instead of the acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS manufactured by Cheil Industries, , A foamable resin composition and a foamed product were prepared in the same manner as in Example 1.

Comparative Example  5

2 parts by weight of calcium carbonate (manufacturer: OMYA KOREA Co., Ltd., product name: KRISTON-SS) was used instead of the acrylonitrile-butadiene-styrene graft copolymer resin (g-ABS manufactured by Cheil Industries, , A foamable resin composition and a foamed product were prepared in the same manner as in Example 1.

Property evaluation method

(1) Average cell size of the foam (unit: 占 퐉): The cross-section of the foam prepared in the above Examples and Comparative Examples was cut and the cell size of the foam was confirmed using an optical microscope at a magnification of 200. The average cell size was arbitrarily selected / measured for 10 cell sizes in three or more foamed ribs, and the average value was obtained.

(2) Density (unit: kg / m ³ ): The foam prepared in the above Examples and Comparative Examples was cut into a size of 300 mm × 300 mm × 50 mm, dried at a temperature of 60 ° C. or higher for 48 hours or more, And the density was calculated by dividing the weight of the specimen by the volume before measuring the thermal conductivity.

(3) Thermal Conductivity (Unit: W / mK): The foam prepared in the above Examples and Comparative Examples was cut into a size of 300 mm × 300 mm × 50 mm, dried at a temperature of 60 ° C. or higher for 48 hours or more, After storing at room temperature for 24 hours, the initial thermal conductivity was measured according to KS L 9016 using a Heat Flow Meter (HFM 436, manufactured by NETZSCH Gerate bau GmbH) and the results are shown in Table 1 below.

(4) Compressive Strength (unit: N / cm ² ): The foam prepared in the above Examples and Comparative Examples was cut into a size of 50 mm 50 mm 50 mm, dried at a temperature of 60 ° C or higher for 48 hours or more, After being stored at room temperature for 24 hours, the compressive strength was measured by INSTRON UNIVERSAL TESTING MACHINE (model: 3365) according to KS M ISO 844.

(5) Foamability (unit: times): The foamed resin composition (mini pellet) prepared in the above Examples and Comparative Examples was supplied with steam at a pressure of 0.2 kg / cm ² for 5 minutes to perform foaming, After 2 hours of drying, the expansion ratio was measured. Measurement of the expansion ratio is a measuring cylinder, and then by measuring the weight and volume of the foamed granules (foamed), dried using the scale of calculating the density of the expanded granules, foam former density 1 g / basis cm ³ 1-fold by the expansion ratio Respectively.

Example Comparative Example One 2 3 One 2 3 4 5 Average cell size (탆) / distribution 122 /
Uniformity 154 /
Uniformity 117 /
Uniformity 758 /
Unevenness 453 /
Unevenness 524 /
Unevenness 461 /
Unevenness 439 /
Unevenness Density (kg / m ³ ) 19.4 20.2 19.8 20.6 20.1 19.3 20.2 20.4 Thermal conductivity (W / mK) 0.0316 0.0320 0.0317 0.0322 0.0320 0.0321 0.0322 0.0322 Compressive strength (N / cm ² ) 10.2 10.3 9.7 6.8 7.1 6.7 7.3 7.3 Foaming (times) 87 85 92 63 67 68 64 65

From the results shown in Table 1, it can be seen that the foamable resin composition and the foam (Examples 1 to 3) according to the present invention have a foam cell size of 154 μm or less and small and uniform, a compressive strength of 9.7 N / cm ² or more, a thermal conductivity of 0.0316 to 0.0320 W / m 占., and the foaming property of the foamable resin composition is 85 times or more. It is explained that a rubber-modified vinyl-based graft copolymer having good compatibility with an aromatic vinyl-based resin is used as a nucleating agent, indicating that sufficient dispersion has been achieved in the extrusion process.

On the other hand, in the case of Comparative Example 1-5 in which a nucleating agent is not used or a general nucleating agent is used, it can be confirmed that the cell is large in size and non-uniform, has low compressive strength and low foamability. Particularly, it is explained that even if foaming proceeds under the same conditions, the low foamability is due to the fact that the overall cell strength is low due to large and unevenness of the cells, so that shrinkage can easily occur during the foaming process. In addition, even when the inorganic nucleating agents (Comparative Examples 4 and 5) are used, the calcium carbonate in the form of fine powder is not dispersed sufficiently uniformly, and in some cases, the cell produces small foaming lips, but as a whole, Was found to be severe.

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 (19)

Aromatic vinyl resins;
Rubber-modified vinyl-based graft copolymer; And
blowing agent;
Wherein the foamable resin composition is a foamable resin composition.
The foamable resin composition according to claim 1, wherein the rubber-modified vinyl-based graft copolymer is obtained by graft-copolymerizing a rubber-like polymer with a monomer mixture comprising an aromatic vinyl monomer and a vinyl cyan monomer.
3. The foamable resin composition according to claim 2, wherein the rubber-like polymer has an average particle diameter (Z-average) of 0.2 to 0.35 mu m.
The foamable resin composition according to claim 2, wherein the rubbery polymer has a gel content of 70 to 90% by weight.
The foamable resin composition according to claim 1, wherein the aromatic vinyl resin is a resin obtained by polymerizing a monomer containing at least one of styrene,? -Methylstyrene, vinyltoluene, and chlorostyrene.
The foamable resin composition according to claim 1, wherein the foaming agent comprises at least one of a hydrocarbon compound and a fluorohydrocarbon.
The aromatic vinyl resin composition according to claim 1, wherein the content of the rubber-modified vinyl-based graft copolymer is 0.1 to 10 parts by weight based on 100 parts by weight of the aromatic vinyl-based resin, and the content of the blowing agent is 100 parts by weight of the aromatic vinyl- By weight, based on the total weight of the foamable resin composition.
The foamable resin composition according to claim 1, wherein the foamable resin composition further comprises a heat insulating material.
The foamable resin composition according to claim 8, wherein the heat insulating material comprises at least one of graphite, carbon black, carbon nanotubes, halloysite, hydrolytic bentonite, and metallic aluminum powder.
The foamable resin composition according to claim 8, wherein the content of the heat insulating material is 0.5 to 5 parts by weight based on 100 parts by weight of the thermoplastic resin.
The foamable resin composition according to claim 1, wherein the foamable resin composition has an expansion ratio of 70 to 130 when heated for 5 minutes with steam at a pressure of 0.2 kg / cm ² .
An aromatic vinyl resin and a rubber-modified vinyl-based graft copolymer to form a mixed composition; And
Injecting a foaming agent into the mixed composition and extruding the mixture;
Wherein the foamed resin composition is a foamed resin composition.
13. The method for manufacturing a foamable resin composition according to claim 12, wherein the mixed composition further comprises a heat insulating material.
Aromatic vinyl resins; And
A rubber-modified vinyl-based graft copolymer.
15. The foam of claim 14, wherein the foam further comprises a heat insulating material.
The method of claim 14, wherein the thermal conductivity of the foam according to KS L 9016, 20 ± 1.5 kg / m density and 300 mm of the ³ × 300 mm × 0.030 to a specimen based on having a 50 mm size 0.033 W / m * K ≪ / RTI >
The method of claim 14, wherein the compressive strength of the foam is a foam, characterized in that on the basis of KS M ISO 844, 50 mm × 50 mm × 50 mm as a sample based on having a size of 8 to 12 N / cm ^2.
Modified vinyl-based graft copolymer is dispersed in a continuous phase containing an aromatic vinyl resin,
A foam having an average cell size of 100 to 250 占 퐉.
12. A foamed article obtained by foaming a foamable resin composition according to any one of claims 1 to 11.