KR20240045769A - Expandable resin composition, method for preparing the same and foamed molded article produced therefrom - Google Patents

Abstract

The foamable resin composition of the present invention contains 40 to 85% by weight of polypropylene resin; 10 to 55% by weight of polyolefin-based elastomer; and 1.5 to 13% by weight of graphite; a foamable resin composition in the form of foamed particles obtained by foaming the resin composition to a foaming ratio of 20 to 50 times and an average cell size of 100 to 300 ㎛, measured according to ISO 845. It is characterized by a density of 20 to 45 g/L and a dynamic elastic modulus measured in accordance with KS F 2868 of 8 to 28 MN/m ³ . The foamable resin composition is excellent in sound insulation, heat insulation, compressive strength, etc.

Description

Foamable resin composition, manufacturing method thereof, and foam molded article manufactured therefrom {EXPANDABLE RESIN COMPOSITION, METHOD FOR PREPARING THE SAME AND FOAMED MOLDED ARTICLE PRODUCED THEREFROM}

The present invention relates to a foamable resin composition, a method for producing the same, and a foam molded article manufactured therefrom. More specifically, the present invention relates to a foamable resin composition having excellent sound insulation, heat insulation, compressive strength, etc., a manufacturing method thereof, and a foam molded article manufactured therefrom.

A foamable resin composition in the form of foam particles can be manufactured by putting the foamable resin composition in a high-pressure reactor along with water, using carbon dioxide gas, etc. as a foaming agent, and discharging under reduced pressure under certain temperature and pressure conditions. The produced foam particles can be molded into a mold. It can be manufactured into a molded product (foam molded body) by filling, heating and fusing it. The molded products manufactured in this way are excellent in rigidity, lightness, cushioning, waterproofing, heat retention, and insulation, and are used in various fields such as packaging materials for home appliances, boxes for agricultural and marine products, father and son, and insulation materials for building materials.

Among these, with regard to regulation of floor impact noise in the construction field, the problem of inconsistency between certificate notation and field performance (difference from field performance: 60%, 2019 Board of Audit and Inspection) was reported. Results were reported to be satisfactory for light impact, but unsatisfactory for heavy impact. As a result, after 2022, the regulation of floor impact noise will change from a pre-accreditation system to a post-evaluation system, and from July 2022 onwards, performance tests will be conducted on site before completion. However, there is a problem that it is difficult to pass field performance tests with existing materials.

Generally, in order to improve the sound insulation of a cushioning material (foam molded body), a method of lowering the dynamic elastic coefficient of the cushioning material is used. Methods for lowering the dynamic elastic coefficient include laminating two or more types of materials in succession or removing the surface that contacts the floor. You can try reducing the area, applying additives, or using a high-magnification (low-density) product.

However, when two or more types of materials are laminated, quality problems may occur during the adhesion process. In the case of a method that reduces the area of the surface in contact with the floor, there is a risk that the strength of the final product itself will be lowered, and in the case of a method of applying additives, the adverse effect of the additives being smeared during post-processing may occur. In addition, when using a high-magnification (low-density) product, it is not easy to withstand the weight of the concrete constructed on top of the cushioning material, and there is a risk of damage due to workers stepping on it. Furthermore, in the case of applying additives, if additives such as graphite are added during the polymerization of foam particles to make foam, or if additives are applied to the surface of a foam molded product made of general foam particles, the additive may fall off. There is a concern that the dynamic elastic coefficient of the cushioning material may vary from product to product.

Accordingly, there is a need to develop a foamable resin composition that has excellent sound insulation (blocks light and heavy impact sounds), heat insulation, etc. without these problems.

The background technology of the present invention is disclosed in Korean Patent Publication No. 10-2009-0121088, etc.

The purpose of the present invention is to provide a foamable resin composition with excellent sound insulation, heat insulation, compressive strength, etc.

Another object of the present invention is to provide a method for producing the foamable resin composition.

Another object of the present invention is to provide a foam molded article formed from the foamable resin composition.

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

1. One aspect of the present invention relates to a foamable resin composition. The foamable resin composition contains 40 to 85% by weight of polypropylene resin; 10 to 55% by weight of polyolefin-based elastomer; and 1.5 to 13% by weight of graphite; a foamable resin composition in the form of foamed particles obtained by foaming the resin composition to a foaming ratio of 20 to 50 times and an average cell size of 100 to 300 ㎛, measured according to ISO 845. It is characterized by a density of 20 to 45 g/L and a dynamic elastic modulus measured in accordance with KS F 2868 of 8 to 28 MN/m ³ .

2. In the first embodiment, the polypropylene resin may include one or more of propylene homopolymer, propylene-ethylene random copolymer, and ethylene-propylene copolymer.

3. In the first or second embodiment, the polyolefin-based elastomer may include one or more of ethylene-octene rubber, ethylene-propylene rubber, ethylene-butene rubber, and ethylene propylene diene monomer rubber.

4. In embodiments 1 to 3, the weight ratio of the polyolefin-based elastomer and the graphite may be 1:0.05 to 1:0.5.

5. Another aspect of the present invention relates to a method for producing a foamable resin composition. The manufacturing method includes preparing a mixture by mixing a dispersion medium containing water and a dispersant with a resin composition containing 40 to 85% by weight of polypropylene resin, 10 to 55% by weight of polyolefin elastomer, and 1.5 to 13% by weight of graphite; And adding a foaming agent to the mixture and foaming the mixture so that the foaming ratio is 20 to 50 times and the average cell size is 100 to 300 ㎛, and the density measured according to ISO 845 is 20 to 45 g/L. and the dynamic elastic modulus measured according to KS F 2868 is 8 to 28 MN/m ³ .

6. In the above 5 embodiments, the foaming involves heating and pressurizing the mixture into which the foaming agent is added to a temperature condition of 140 to 160°C and a pressure condition of 25 to 47 kgf/cm ² and then exposing it to room temperature and atmospheric pressure conditions. You can.

7. Another aspect of the present invention relates to a foam molded body. The foam molded body is characterized in that it is formed by filling a mold with the foamable resin composition according to any one of 1 to 4 above, followed by heating and fusing.

8. In the above 7 embodiments, the foam molded body may have a thermal conductivity of 0.032 to 0.035 W/m·K as measured according to ISO 8301.

9. In the 7th or 8th embodiment, the foam molded body is compressed in accordance with KS M ISO844 by compressing a foam molded body specimen with a size of 100 mm When deformed by 25 mm), the measured compressive strength can be more than 125 kPa.

The present invention has the effect of providing a foamable resin composition having excellent sound insulation, heat insulation, compressive strength, etc., a manufacturing method thereof, and a foam molded article manufactured therefrom.

Hereinafter, the present invention will be described in detail as follows.

The foamable resin composition according to the present invention includes (A) polypropylene resin; (B) polyolefin-based elastomer; and (C) graphite.

In this specification, “a to b” indicating a numerical range is defined as “≥a and ≤b”.

(A) Polypropylene resin

The polypropylene resin according to one embodiment of the present invention is a base resin for forming a foamable resin composition and a foam molded body, and is applied together with a polyolefin-based elastomer and graphite to provide heat insulation and sound insulation properties of the foamable resin composition (foamed particles) and the foam molded body. , compressive strength, etc. can be improved. The polypropylene resin is a propylene homopolymer; propylene-ethylene random copolymer; An ethylene-propylene copolymer in which the propylene homopolymerization portion and the ethylene-propylene copolymerization portion are stepwise polymerized in a reactor; Or it may include a combination thereof. For example, propylene-ethylene random copolymer can be used.

In a specific example, the polypropylene resin has a melt-flow index measured under ASTM D1238 at 230°C and a load of 2.16 kg of 1 to 50 g/10 minutes, for example, 5 to 30 g. /It could be 10 minutes. Within the above range, the mechanical strength, moldability, foamability, etc. of the foamable resin composition may be excellent.

In a specific example, the polypropylene resin may be included in 40 to 85% by weight, for example, 45 to 80% by weight, based on 100% by weight of the total foamable resin composition. If the content of the polypropylene resin is less than 40% by weight, there is a risk that the heat insulation and compressive strength of the foamable resin composition and the foam molded product may decrease, and if the content of the polypropylene resin exceeds 85% by weight, the sound insulation properties of the foamable resin composition and the foam molded product, There is a risk that insulation properties, etc., may deteriorate.

(B) Polyolefin-based elastomer

The polyolefin-based elastomer according to one embodiment of the present invention can be applied to polypropylene resin together with graphite to improve the heat insulation, sound insulation, compressive strength, etc. of the foamable resin composition (foamed particles) and the foam molded body. Polyolefin-based elastomers used in polyolefin foamable resin compositions can be used.

In specific examples, the polyolefin-based elastomer may include ethylene-octene rubber, ethylene-propylene rubber, ethylene-butene rubber, ethylene propylene diene monomer rubber, and combinations thereof. Preferably, ethylene-octene rubber can be used.

In a specific example, the polyolefin-based elastomer may have an ethylene content of 10 to 60% by weight, for example, 15 to 50% by weight, as measured using an IR analyzer. Within the above range, compatibility and bonding strength with constituents may be excellent, and the sound insulation properties of the foamable resin composition and foam molded body may be excellent.

In a specific example, the polyolefin-based elastomer may be included in an amount of 10 to 55% by weight, for example, 15 to 55% by weight, based on 100% by weight of the total foamable resin composition. If the content of the polyolefin-based elastomer is less than 10% by weight, there is a risk that the heat insulation and compressive strength of the foamable resin composition and the foam molded product may decrease, and if it exceeds 55% by weight, the sound insulation properties of the foamable resin composition and the foam molded product, There is a risk that insulation properties, etc., may deteriorate.

(C) Graphite

Graphite according to one embodiment of the present invention can be applied to polypropylene resin together with polyolefin-based elastomer to improve the heat insulation, sound insulation, compressive strength, etc. of the foamable resin composition (foamed particles) and foam molded body. , graphite applied to normal foamable resin compositions can be used.

In a specific example, the graphite may have an average particle size of 10 to 30 ㎛, for example, 15 to 25 ㎛, as measured by a scanning electron microscope (SEM), and may be in the form of a flake. You can have Within the above range, the heat insulation and sound insulation properties of the foamable resin composition and the foam molded body may be excellent.

In a specific example, the graphite may be included in an amount of 1.5 to 13% by weight, for example, 2 to 10% by weight, based on 100% by weight of the total foamable resin composition. If the graphite content is less than 1.5% by weight, there is a risk that the thermal insulation properties of the foamable resin composition and the foam molded product may be deteriorated, and if it exceeds 13% by weight, there is a risk that the thermal insulation properties of the foamable resin composition and the foam molded product may be deteriorated. .

In a specific example, the weight ratio of the polyolefin-based elastomer and the graphite may be 1:0.05 to 1:0.5, for example, 1:0.06 to 1:0.4. Within the above range, the sound insulation, heat insulation, compressive strength, and balance of physical properties of the foamable composition and the foam molded product may be superior.

The foamable resin composition according to one embodiment of the present invention is prepared by preparing the resin composition containing the polypropylene resin, polyolefin-based elastomer, and graphite so that the foaming ratio is 20 to 50 times and the average cell size is 100 to 300 ㎛. It is in the form of foamed particles manufactured by foaming.

In a specific example, the resin composition may be in the form of a pellet obtained by mixing the components and melt-extruding the mixture at 150 to 240°C, for example, 160 to 230°C using a conventional single-screw or twin-screw extruder.

In a specific example, the foamable resin composition (foamed particles) may have a foaming ratio of 20 to 50 times, for example, 25 to 45 times, and an average cell size of 100 to 300 ㎛, for example, 150 to 300 ㎛. there is. If the expansion ratio of the foamed particles (foamable resin composition) is outside the above range, there is a risk that sound insulation, heat insulation, foam moldability (fusibility), mechanical properties, etc. may be reduced. Here, the foaming ratio of the foamed particles can be measured by a direct immersion method. In detail, the weight and volume of the dried foamed particles are measured using a measuring cylinder and scale to calculate the density of the particles, and then the resin composition before foaming. It is a value converted by multiplying the particle density of 0.9 g/cm ³ by 1, and the average size of the cell is calculated by cooling the foamed particles with liquid nitrogen, cutting a cross section, and measuring the cells of the foamed particles using a SEM (Scanning Electron Microscope). This value is obtained by measuring more than 10 diameters (sizes) and then calculating the average value.

In a specific example, the foamable resin composition (foamed particles) may have a density of 20 to 45 g/L, for example, 25 to 40 g/L, as measured according to ISO 845. If the density of the foamable resin composition (foamed particles) is less than 20 g/L, there is a risk that compressive strength, etc. may decrease, and if it exceeds 45 g/L, there is a risk that sound insulation, heat insulation, etc. may decrease.

In a specific example, the foamable resin composition (foamed particles) may have a dynamic elastic coefficient of 8 to 28 MN/m ³ , for example, 10 to 27 MN/m ³ , as measured according to KS F 2868. If it is outside the above range, there is a risk that the sound insulation properties of the foamable resin composition and the foam molded article may decrease.

The foamable resin composition according to one embodiment of the present invention may further include additives used in conventional foamable resin compositions to the extent that they do not impair the purpose and effect of the present invention. Examples of the additive include, but are not limited to, antioxidants, light stabilizers, heat stabilizers, flame retardants, colorants, plasticizers, slip agents, and combinations thereof. When using the additive, its content may be 0.001 to 40% by weight, for example, 0.1 to 30% by weight, based on 100% by weight of the total foamable resin composition.

The foamable resin composition according to one embodiment of the present invention may be manufactured according to a known method for producing foamed particles. For example, preparing a mixture by mixing the resin composition with a dispersion medium containing water and a dispersant; Then, it can be manufactured by adding a foaming agent to the mixture and foaming it to have the foaming ratio and the average size of the cells.

In an embodiment, the dispersant may include one or more of higher fatty acids, higher fatty acid esters, and higher fatty acid amides.

In an embodiment, the resin composition may be introduced into a reactor in which a dispersion medium is present, or a dispersion medium may be introduced into the reactor together with the resin composition to form a mixture.

In a specific example, the foaming agent may be a foaming agent used in conventional foam particles, for example, carbon dioxide, propane, butane, hexane, pentane, heptane, cyclobutane, cyclohexane, methyl chloride, ethyl chloride, and methylene. Chloride, dimethyl ether, diethyl ether, methyl ethyl ether, nitrogen, argon, etc. can be used alone or in a mixture of two or more.

In a specific example, the foaming is performed by subjecting the mixture to which the foaming agent is added under temperature conditions of 140 to 160°C, for example, 140 to 155°C, and pressure conditions of 25 to 47 kgf/cm ² , for example, 25 to 45 kgf/cm ² This can be performed by heating and pressurizing and then exposing to room temperature and atmospheric pressure conditions. Under the above temperature and pressure conditions, foamed particles (foamable resin composition) with a foaming ratio of 20 to 50 times, for example, 25 to 45 times, and an average cell size of 100 to 300 ㎛, for example, 150 to 300 ㎛ are obtained. You can.

In a specific example, the foamed particles (foamable resin composition) may have an average particle diameter measured with a vernier caliper of 1 to 7 mm, for example, 2 to 6 mm, but is not limited thereto. Within the above range, foam moldability, etc. may be excellent.

The foam molded body according to the present invention can be formed by filling the foamable resin composition (foamed particles) into a mold and fusing it, and can be easily manufactured by those skilled in the art. For example, the foam molded body is filled (introduced) with the foam particles into a non-hermetic mold, and saturated steam (e.g., saturated steam at a pressure of 2.0 to 3.5 bar) is supplied to the mold for about 30 seconds, It can be manufactured by fusing the foamed particles together and drying them.

In a specific example, the foam molded body may have a thermal conductivity measured according to ISO 8301 of 0.032 to 0.035 W/m·K, for example, 0.033 to 0.035 W/m·K.

In a specific example, the foam molded body is compressed under the condition of 5 mm/min on a 100 mm × 100 mm × 50 mm size foam molded body specimen according to KS M ISO844, and is deformed to 50% (25 mm) of the initial thickness. The compressive strength measured may be 125 kPa or more, for example, 130 to 200 kPa.

In a specific example, the foam molded body has excellent sound insulation, heat insulation, compressive strength, etc., and is therefore useful as an interlayer sound insulating material for construction.

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

Example

Hereinafter, the specifications of each component used in the examples and comparative examples are as follows.

(A) Polypropylene resin

Propylene-ethylene random copolymer (manufacturer: Lotte Chemical, product name: SEP-550) was used.

(B) Polyolefin-based elastomer

Ethylene-octene rubber (manufacturer: LG Chemical, product name: LC100) was used.

(C) Insulating material

Graphite (manufacturer: Qingdao xinghe graphite, product name: Flake Graphite (fixed carbon 99%, 1200 Mesh)) was used.

Examples 1 to 5 and Comparative Examples 1 to 8

Each of the above components was added in the amounts shown in Tables 1, 2, and 3 below, and then extruded at 220°C to prepare a resin composition (1.2 mg, in the form of a pellet with a diameter of 0.8 mm × thickness of 1.1 mm). For extrusion, a single-screw extruder (screw rotation speed: 700 rpm) with L/D = 34 and a diameter of 40 mm was used. Next, 100 parts by weight of the resin composition was added to an autoclave along with 300 parts by weight of a dispersion medium (water to which a dispersant was added). After carbon dioxide (CO ₂ ), a foaming agent, was added to the autoclave, the temperature and pressure (foaming temperature and foaming pressure) inside the autoclave were adjusted while stirring as shown in Tables 1, 2, and 3 below. Next, the contents of the autoclave were exposed to the air to prepare foamed particles (foamable resin composition). The foamed particles were dried at room temperature for 24 hours, then placed in a pressurized tank and pressurized from atmospheric pressure (1 bar) to 3 bar over 10 hours, and then filled into a mold (450 mm × 450 mm × 50 mm). Afterwards, saturated steam at 2.5 bar was supplied to the mold for 30 seconds, the foam particles were fused together, cooled, taken out, and dried in a 70°C convection oven for 12 hours to prepare a foam molded body. The physical properties of the manufactured foam molded body were evaluated by the following method, and the results are shown in Tables 1, 2, and 3 below.

How to measure physical properties

(1) Cell average size: A specimen of foamed particles (foamable resin composition) foamed at the expansion ratios shown in Tables 1, 2, and 3 below was cooled with liquid nitrogen, then cut into sections, and 10 cells were randomly selected. The diameter (size) of each cell was measured using a SEM (Scanning Electron Microscope), and then the average value of the cell diameter (average size, unit: ㎛) was calculated.

(2) Density (unit: g/L): The density of the foamed particle specimen was measured according to ISO 845.

(3) Dynamic elastic modulus (unit: MN/m ³ ): According to KS F 2868, the dynamic elastic modulus of the foam particle specimen was measured.

(4) Thermal conductivity (unit: W/m·K): The thermal conductivity of the foam molded specimen was measured according to ISO 8301.

(5) Compressive strength (unit: kPa): In accordance with KS M ISO844, a 100 mm × 100 mm × 50 mm foam molded specimen was compressed using UTM equipment under the condition of 5 mm/min, and the initial thickness was 50 mm. Compressive strength when deformed in % (25 mm) was measured.

Example One 2 3 4 5 (A) (parts by weight) 76 66 46 68 60 (B) (part by weight) 20 30 50 30 30 (C) (parts by weight) 4 4 4 2 10 Foaming temperature (℃) 145 145 145 145 145 Foaming pressure (kg/cm ² ) 40 40 40 40 40 Foaming ratio (fold) 30 30 30 30 30 Cell average size (㎛) 150 200 250 250 160 Density (g/L) 30 30 30 30 30 Dynamic elastic modulus (MN/m ³ ) 25 16 17 23 20 Thermal conductivity (W/m·K) 0.035 0.034 0.035 0.035 0.035 Compressive strength (kPa) 180 150 130 140 160

Comparative example One 2 3 4 (A) (parts by weight) 91 36 69 55 (B) (part by weight) 5 60 30 30 (C) (parts by weight) 4 4 One 15 Foaming temperature (℃) 145 145 145 145 Foaming pressure (kg/cm ² ) 40 40 40 40 Foaming ratio (fold) 30 30 30 30 Cell average size (㎛) 250 260 220 150 Density (g/L) 30 30 30 30 Dynamic elastic modulus (MN/m ³ ) 32 16 26 22 Thermal conductivity (W/m·K) 0.037 0.037 0.037 0.037 Compressive strength (kPa) 240 120 150 160

Comparative example 5 6 7 8 (A) (parts by weight) 66 66 66 66 (B) (part by weight) 30 30 30 30 (C) (parts by weight) 4 4 4 4 Foaming temperature (℃) 135 165 145 145 Foaming pressure (kg/cm ² ) 50 20 50 20 Foaming ratio (fold) 30 30 53 18 Cell average size (㎛) 90 350 300 150 Density (g/L) 30 30 17 50 Dynamic elastic modulus (MN/m ³ ) 31 33 25 40 Thermal conductivity (W/m·K) 0.038 0.038 0.034 0.038 Compressive strength (kPa) 130 150 60 370

From the above results, it can be seen that the foamable resin composition (foamed particles) of the present invention has excellent cell quality and can form a foam molded body with excellent sound insulation (dynamic elastic coefficient), heat insulation (thermal conductivity), and compressive strength. there is. In addition, since the average cell size is in the range of 100 to 300 ㎛, it can be seen that secondary processing is excellent due to an appropriate shrinkage rate, and the density is in the range of 20 to 45 g/L, so sound insulation (dynamic elastic coefficient ), insulation (thermal conductivity), compressive strength, and the balance of these physical properties are excellent.

On the other hand, in the case of Comparative Example 1 in which an excessive amount of polypropylene resin was used and a small amount of polyolefin-based elastomer, it can be seen that the sound insulation and heat insulation properties were reduced, and in the case of Comparative Example 1 in which a small amount of polypropylene resin was used and an excessive amount of polyolefin-based elastomer was used, In the case of 2, it can be seen that the thermal insulation properties, compressive strength, etc. were decreased, and in the case of Comparative Example 3, where a small amount of graphite was used, the thermal insulation properties, etc., were found to be decreased, and in the case of Comparative Example 4, where an excessive amount of graphite was used, the thermal insulation properties, etc. were decreased. Able to know. In the case of Comparative Example 5, where the average cell size is below the range of the present invention, it can be seen that the sound insulation, heat insulation, etc. are reduced, and in the case of Comparative Example 6, where the average cell size is beyond the range of the present invention, the sound insulation, heat insulation, etc. are reduced. You can see that it has been done. In addition, in the case of Comparative Example 7, where the expansion ratio exceeds the range of the present invention and the density is below the range of the present invention, it can be seen that the compressive strength, etc. is decreased, and the expansion ratio is below the range of the present invention, and the density is less than the range of the present invention. In the case of Comparative Example 8, which exceeds the range, it can be seen that sound insulation, heat insulation, etc. are deteriorated.

So far, the present invention has been examined focusing on the embodiments. A person skilled in the art to which the present invention pertains will understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed embodiments should be considered from an illustrative rather than a restrictive perspective. The scope of the present invention is indicated in the claims rather than the foregoing description, and all differences within the equivalent scope should be construed as being included in the present invention.

Claims (9)

40 to 85% by weight of polypropylene resin; 10 to 55% by weight of polyolefin-based elastomer; and 1.5 to 13% by weight of graphite; a foamable resin composition in the form of expanded particles obtained by foaming the resin composition to a foaming ratio of 20 to 50 times and an average cell size of 100 to 300 ㎛,
The density measured according to ISO 845 is 20 to 45 g/L,
A foamable resin composition characterized in that the dynamic elastic modulus measured according to KS F 2868 is 8 to 28 MN/m ³ .
The foamable resin composition according to claim 1, wherein the polypropylene includes at least one of propylene homopolymer, propylene-ethylene random copolymer, and ethylene-propylene copolymer.
The foamable resin composition according to claim 1, wherein the polyolefin-based elastomer includes one or more of ethylene-octene rubber, ethylene-propylene rubber, ethylene-butene rubber, and ethylene propylene diene monomer rubber.
The foamable resin composition according to claim 1, wherein the weight ratio of the polyolefin-based elastomer and the graphite is 1:0.05 to 1:0.5.
Preparing a mixture by mixing a dispersion medium containing water and a dispersant with a resin composition containing 40 to 85% by weight of polypropylene resin, 10 to 55% by weight of polyolefin-based elastomer, and 1.5 to 13% by weight of graphite; and
Adding a foaming agent to the mixture and foaming the mixture so that the foaming ratio is 20 to 50 times and the average cell size is 100 to 300 ㎛,
The density measured according to ISO 845 is 20 to 45 g/L,
A method for producing a foamable resin composition, characterized in that the dynamic elastic modulus measured according to KS F 2868 is 8 to 28 MN/m ³ .
The method of claim 5, wherein the foaming is performed by heating and pressurizing the mixture containing the foaming agent to a temperature of 140 to 160°C and a pressure of 25 to 47 kgf/cm ² and then exposing the mixture to room temperature and atmospheric pressure. A method of producing a foamable resin composition.
A foam molded article, which is formed by filling a mold with the foamable resin composition according to any one of claims 1 to 4, followed by heating and fusing.
The foam molded article according to claim 7, wherein the foam molded article has a temperature of 0.032 to 0.035 W/m·K as measured according to ISO 8301.
The method of claim 7, wherein the foam molded body is compressed in accordance with KS M ISO844 by compressing a 100 mm A foam molded body, characterized in that the compressive strength measured when deformed is 125 kPa or more.