KR20230099596A - Injection resin composition for home appliance and refrigerator using the same - Google Patents

Abstract

In the present specification, an injection resin composition for home appliances having excellent fluidity, high tensile strength, and chemical resistance, and a refrigerator to which the same is applied are disclosed.
A refrigerator according to an embodiment of the present invention includes a cabinet frame forming an exterior of the refrigerator; A liner that isolates the inside of the refrigerator and the insulation; and an insulating material provided between the outer casing and the inner casing, wherein the inner casing may include an injection high impact polystyrene (HIPS) material or an injection molding acrylonitrile butadiene styrene (ABS) ALLOY material.

Description

Injection resin composition for home appliance and refrigerator using the same {Injection resin composition for home appliance and refrigerator using the same}

The present invention relates to an injection-molded resin composition for home appliances and a refrigerator to which the same is applied, and more particularly, to a chemical-resistant, high-flow injection resin composition using an injection-type HIPS or injection-type ABS Alloy resin composition and a refrigerator to which the same is applied.

The inner box of the refrigerator is a part that isolates the inside of the refrigerator from foamed urethane for insulation.

Conventionally, the inner case of a refrigerator is manufactured by extrusion sheet production, vacuum forming, assembly, and urethane foaming processes. However, according to the conventional process, extrusion, vacuum forming equipment and process costs are excessively required. In addition, the product manufactured by vacuum forming has a problem in that it is difficult to process the edge corner, and the thin part is swollen due to the internal gas pressure during the foaming process, and the appearance quality is deteriorated.

In order to improve this, research on methods for manufacturing the inner case of the refrigerator by injection, assembly, and urethane foaming processes is increasing. On the other hand, as refrigerators become larger, high fluidity for thin film injection is required, and sufficient chemical resistance and tensile strength are required to improve quality.

However, the conventional resin composition for the injection process has poor chemical resistance, and cracks occur in the temperature cycle evaluation at -30 to 70 ° C, or surface quality is deteriorated due to contamination with vegetable oil. In addition, conventional resin compositions have a problem in that injection molding is difficult due to low fluidity.

An object of the present invention to solve the above problems is to provide an injection resin composition for home appliances, excellent in all of high fluidity, high tensile strength and chemical resistance, and a refrigerator to which the same is applied.

A refrigerator according to an embodiment of the present invention includes a cabinet frame forming an exterior of the refrigerator; A liner that isolates the inside of the refrigerator and the insulation; and an insulating material provided between the outer casing and the inner casing, wherein the inner casing may include an injection high impact polystyrene (HIPS) material or an injection molding acrylonitrile butadiene styrene (ABS) ALLOY material.

In addition, in the refrigerator according to an embodiment of the present invention, the inner case is composed of an upper part, a side part, and a lower part, the upper part and the side part of the inner case include an injection HIPS material, and the lower part of the inner case is an injection ABS ALLOY material. can include

In addition, in the refrigerator according to an embodiment of the present invention, the inner case may have a thickness of 1 mm to 2.5 mm.

In addition, in the refrigerator according to an embodiment of the present invention, the injection HIPS material may include 45 to 65 parts by weight of a chemical resistant HIPS material and 35 to 55 parts by weight of a high flow HIPS material based on 100 parts by weight of the injection HIPS material. there is.

In addition, in the refrigerator according to an embodiment of the present invention, the chemical resistant HIPS material includes 9.5 to 12% by weight of rubber and the remainder of PS (Polystyrene), and the rubber may have an average particle diameter of 6.0 to 8.5 μm. .

In addition, in the refrigerator according to an embodiment of the present invention, the high flow HIPS material includes 7.0 to 9.0% by weight of rubber and the rest and the rest PS (Polystyrene), and the average particle diameter of the rubber is 1.2 to 1.8 μm. can

In addition, in the refrigerator according to an embodiment of the present invention, the injection HIPS material may have a melt index (MI) of 6.0 to 9.5 g/10min.

In addition, in the refrigerator according to an embodiment of the present invention, the injection ABS ALLOY material is based on 100 parts by weight of the injection ABS ALLOY material, SAN (Styrene-Acrylonitrile) resin 65 to 85 parts by weight, g-AAS (acrylonitrile - Polybutylacrylic acid-styrene copolymer resin) 10 to 20 parts by weight, g-ABS (acrylonitrile-butadiene-styrene copolymer resin) 5 to 15 parts by weight and ethylene / alkyl (meth) acrylate 3 to 6 parts by weight can include

In addition, in the refrigerator according to an embodiment of the present invention, the SAN resin may include 25 to 29% by weight of acrylonitrile and the remainder polystyrene (PS), and may have a weight average molecular weight of 120,000 to 160,000.

In addition, in the refrigerator according to an embodiment of the present invention, the g-AAS and g-ABS may include 50 to 60% by weight of rubber and the remaining SAN resin, and may have a core-shell shape.

In addition, in the refrigerator according to an embodiment of the present invention, the ethylene/alkyl (meth)acrylate may be represented by Formula 1 below.

Formula 1:

In Formula 1, R1 is hydrogen or a methyl group, and in Formula 1, R2 is an alkyl group of C1 to C12, which is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl group or isobutyl group, and in the above formula (1), m and n are degrees of polymerization, and the ratio of m and n is 300:1 to 10:90.

In addition, in the refrigerator according to an embodiment of the present invention, the injection molding ABS ALLOY material may have a melt index (MI) of 4.5 to 8.0 g/10min.

In addition, the injection HIPS material for home appliances according to an embodiment of the present invention is an injection HIPS material composition for home appliances, including a chemical resistant HIPS material and a high flow HIPS material, based on 100 parts by weight of the injection HIPS material, 45 to 65 parts by weight of a chemical HIPS material and 35 to 55 parts by weight of a high flow HIPS material, and a melt index (MI) may be 6.0 to 9.5 g/10min.

In addition, the injection HIPS material for home appliances according to an embodiment of the present invention may have a tensile strength of 180 to 300 kgf/cm ² and an impact strength of 7 to 16 kgf·cm/cm.

In addition, the injection HIPS material for home appliances according to an embodiment of the present invention, the flexural modulus may be 16000 to 24000 kgf / cm ² .

In addition, the injection-molded HIPS material for home appliances according to an embodiment of the present invention may have a heat deflection temperature (HDT) of 72 to 85 ° C under a load of 1.82 kg.

In addition, the injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention is SAN (Styrene-Acrylonitrile) resin, g-AAS (acrylonitrile-polybutylacrylic acid-styrene copolymer resin), g-ABS (acrylic acid) Ronitrile-butadiene-styrene copolymer resin) and ethylene / alkyl (meth) acrylate as an injection ABS ALLOY material composition for home appliances, based on 100 parts by weight of the injection ABS ALLOY material, SAN resin 65 to 85 parts by weight , 10 to 20 parts by weight of g-AAS, 5 to 15 parts by weight of g-ABS, and 3 to 6 parts by weight of ethylene/alkyl (meth)acrylate, and has a tensile strength of 400 to 520 kgf/cm ² , and an impact strength of It may be 18 to 30 kgf cm/cm.

In addition, the injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention may have a flexural modulus of 18000 to 26000 kgf/cm ² .

In addition, the injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention may have a heat deflection temperature (HDT) of 75 to 90 ° C. under a load of 1.82 kg.

In addition, the injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention may have a melt index (MI) of 4.5 to 8.0 g/10min.

According to an example of the present invention, it is possible to provide an injection resin composition for home appliances, which is excellent in all of high fluidity, high tensile strength, and chemical resistance, and a refrigerator to which the same is applied.

In addition, according to an example of the present invention, it is possible to provide an injection-molded resin composition for home appliances, which is easily processed at the edges and has improved appearance quality, at low cost.

However, the effects that can be achieved by the injection molding resin composition for home appliances according to the embodiments of the present invention and the refrigerator using the same are not limited to those mentioned above, and other effects not mentioned are described in the present invention from the following description. This will be clearly understood by those skilled in the art.

1 is a schematic diagram of a refrigerator according to an embodiment of the present invention.
2 is a flowchart of a refrigerator manufacturing process according to the prior art.
3 is a flowchart of a refrigerator manufacturing process according to an example of the present invention.
4 is a photograph showing the environmental stress cracking (ESC) evaluation results for Comparative Example 6.
5 is a photograph showing the environmental stress cracking (ESC) evaluation result for Example 4.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following examples are presented to sufficiently convey the spirit of the present invention to those skilled in the art. The present invention may be embodied in other forms without being limited to only the embodiments presented herein. In the drawings, in order to clarify the present invention, illustration of parts irrelevant to the description may be omitted, and the size of components may be slightly exaggerated to aid understanding.

Throughout the specification, when a certain component is said to "include", it means that it may further include other components without excluding other components unless otherwise stated.

Expressions in the singular number include plural expressions unless the context clearly dictates otherwise.

A refrigerator according to an embodiment of the present invention includes a cabinet frame forming an exterior of the refrigerator; A liner that isolates the inside of the refrigerator and the insulation; and an insulating material provided between the outer casing and the inner casing, wherein the inner casing may include an injection high impact polystyrene (HIPS) material or an injection molding acrylonitrile butadiene styrene (ABS) ALLOY material.

The inner sleeve may include an upper portion, a side portion, and a lower portion, the upper portion and the side portion of the inner garment may include an injection HIPS material, and the lower portion of the inner injury may include an injection ABS ALLOY material.

1 is a schematic diagram of a refrigerator according to an embodiment of the present invention.

Referring to FIG. 1 , a refrigerator according to one embodiment of the present invention includes an outer box provided on the outermost part of the refrigerator to form an exterior, an inner box separating the inside of the refrigerator from a heat insulating material, and a heat insulating material provided between the outer box and the inner case. can do.

The inner bed may include an injection high impact polystyrene (HIPS) material or an injection acrylonitrile butadiene styrene (ABS) ALLOY material manufactured through an injection molding process.

The injection material manufactured by the injection molding process can implement an internal wound made of five sides by assembling five pieces in the form of a thin film. Here, the 5 surfaces mean the upper part of the uppermost surface, the left and right sides, the side parts of the rear surface, and the lower part of the lower surface.

Upper and side portions of the inner sleeve may include an injection HIPS material, and a lower portion of the inner sleeve may include an injection ABS ALLOY material.

The injection molding ABS ALLOY material has excellent physical properties such as tensile strength, impact strength, and flexural modulus. Therefore, it is preferable to use the injection-molded ABS ALLOY material for the lower part of the inner sleeve that comes in direct contact with items inside the refrigerator, such as food. On the other hand, since the injection HIPS material has a low manufacturing cost, it is preferable to use it for the top and side parts of the inner sleeve in order to secure price competitiveness. However, it is not limited thereto, and if necessary, at least one of an injection ABS ALLOY material and an injection HIPS material may be used to implement the upper, side, and lower parts of the inner sleeve.

In addition, since the outer case of the refrigerator is generally made of steel plate and the inner case of the refrigerator is made of a resin composition, the volume change rate due to external factors such as temperature change is different, and stress may act on the inner case. Therefore, when the stress is high, an injection ABS ALLOY material having excellent physical properties can be used, and when the stress is low, an injection HIPS material having excellent price competitiveness can be used.

For example, an injection ABS alloy material may be used for the inner case of a bulky refrigerator because stress may be high, and an injection HIPS material may be used for the inner case of a refrigerator with a small volume because stress may be small.

A vegetable oil having a similar solubility constant to that of the resin composition may easily penetrate into the resin composition and cause cracking. In particular, since the inner box of the refrigerator constitutes the inside of the refrigerator, vegetable oil is often stored for a long period of time. Therefore, sufficient chemical resistance is required. Meanwhile, examples of the vegetable oil include soybean oil, sesame oil, olive oil, and canola oil, but are not limited thereto.

In addition, the injection-molded ABS ALLOY material and the injection-molded HIPS material can be applied not only to refrigerators, but also to home appliances that require sufficient strength and chemical resistance, such as air conditioners and washing machines.

2 is a flowchart of a refrigerator manufacturing process according to the prior art, and FIG. 3 is a flowchart of a refrigerator manufacturing process according to an example of the present invention.

Referring to FIGS. 2 and 3 , conventional refrigerator inner cases are manufactured by extrusion sheet production, vacuum forming, refrigerator assembly, and urethane foaming processes. However, the inner case of the refrigerator according to one embodiment of the present invention is manufactured by injection molding, refrigerator assembly, and urethane foaming processes.

As described above, when manufacturing the inner case of a refrigerator by vacuum forming, problems such as excessive cost, difficult edge corner processing, and deterioration in external appearance may occur.

However, when manufacturing the inner case of a refrigerator by injection molding, it is possible to reduce equipment and process costs, and thus has excellent price competitiveness. In addition, when manufacturing the inner case of a refrigerator by injection molding, it is easy to process the edges and corners, and it is possible to improve the appearance quality because there is no surface noise caused by the foaming process.

In order to manufacture refrigerator inner cases by injection molding, high fluidity is essential. However, in general, chemical resistance and fluidity have a trade-off relationship and are difficult to satisfy at the same time. In the present invention, it is intended to provide an injection material capable of implementing sufficient chemical resistance while having high fluidity that is easy to injection mold through optimization of the composition.

The inner wound manufactured using the injected HIPS material or the injected ABS ALLOY material in the form of a thin film may have a thickness of 1 mm to 2.5 mm.

If the thickness is too thin, it may be difficult to secure sufficient strength. However, when the thickness is too thick, there is a possibility that the internal space becomes narrow.

Next, the injection HIPS material according to an example of the present invention will be described in detail.

The injection HIPS material may include 45 to 65 parts by weight of a chemical resistant HIPS material and 35 to 55 parts by weight of a high flow HIPS material based on 100 parts by weight of the injection HIPS material.

If the content of the chemical resistant HIPS material is too low, chemical resistance may be inferior. However, when the content of the chemical-resistant HIPS material is excessive, fluidity and tensile strength may be deteriorated.

In addition, if the content of the high-flow HIPS material is too low, the fluidity is poor and injection molding may be difficult. However, if the content of the high-flow HIPS material is excessive, chemical resistance and impact strength may be inferior.

The chemical-resistant HIPS material includes 9.5 to 12 wt% of rubber and the remainder of polystyrene (PS), and the rubber may have an average particle diameter of 6.0 to 8.5 μm. Since chemical resistance improves as the average particle diameter of rubber increases, the chemical resistant HIPS material implements excellent chemical resistance by utilizing rubber having a large average particle diameter.

In addition, the high-flow HIPS material includes 7.0 to 9.0 wt% of rubber and the rest and the rest of PS (Polystyrene), and the rubber may have an average particle diameter of 1.2 to 1.8 μm. The high-flow HIPS material realizes high-flowability with a melt index (MI) of 15 to 19 g/10min by adjusting the rubber content.

Both the chemical-resistant HIPS material and the high-flow HIPS material are rubber-modified polystyrene resins prepared by conventional bulk polymerization methods.

On the other hand, in the present invention, the average means the average of measurement values measured at five arbitrary locations.

By optimizing the contents of the chemical resistant HIPS material and the high flow HIPS material, the injection HIPS material according to the present invention may have a melt index (MI) of 6.0 to 9.5 g/10min.

If the flow index is too low, injection molding may be difficult. However, when the flow index is too high, mechanical properties such as tensile strength and impact strength may be deteriorated.

The injection HIPS material according to the present invention may have a tensile strength of 180 to 300 kgf/cm ² , an impact strength of 7 to 16 kgf cm/cm, and a flexural modulus of 16000 to 24000 kgf/cm ² .

When the tensile strength is low, deformation or cracking may occur during the assembly process. However, when the tensile strength is too high, the fluidity may be lowered and the productivity may be lowered.

When the impact strength is low, there is a concern that cracks may occur in the hook portion for assembly. However, when the impact strength is too high, the fluidity is lowered similarly to the tensile strength, and productivity may be lowered.

When the flexural modulus is low, deformation due to load on the substrate may occur. However, when the flexural modulus is too high, cracks may occur at the hook portion for assembly.

The injection HIPS material according to the present invention may have a heat deflection temperature (HDT) of 72 to 85 ° C under a load of 1.82 kg.

When the heat distortion temperature is low, there is a concern that deformation may occur during the high-temperature assembly process. However, if the heat deflection temperature is too high, the fluidity may decrease and productivity may decrease.

Next, the injection molding ABS ALLOY material according to an example of the present invention will be described in detail.

The injection ABS ALLOY material, based on 100 parts by weight of the injection ABS ALLOY material, SAN (Styrene-Acrylonitrile) resin 65 to 85 parts by weight, g-AAS (acrylonitrile-polybutylacrylic acid-styrene copolymer resin) 10 to 20 It may include 5 to 15 parts by weight of g-ABS (acrylonitrile-butadiene-styrene copolymer resin) and 3 to 6 parts by weight of ethylene/alkyl (meth)acrylate.

If the content of the SAN resin is too low, the tensile strength may decrease. However, if the SAN resin content is too excessive, the impact strength may be deteriorated.

If the content of g-AAS is too low, chemical resistance may deteriorate. However, if the content of g-AAS is too excessive, price competitiveness may deteriorate due to cost increase.

If the g-ABS content is too low, the impact strength may drop. However, if the g-ABS content is too excessive, the fluidity may deteriorate.

When the content of ethylene/alkyl (meth)acrylate is too low, chemical resistance may deteriorate, similar to g-AAS. However, if the content of ethylene/alkyl (meth)acrylate is too excessive, price competitiveness may decrease.

The SAN resin may include 25 to 29% by weight of acrylonitrile and the remainder polystyrene (PS), and may have a weight average molecular weight of 120,000 to 160,000.

If the acrylonitrile content is too low, chemical resistance may be poor. However, if the acrylonitrile content is too high, the impact strength may be lowered.

Meanwhile, the weight average molecular weight herein is a common term indicating the molecular weight of a polymer compound, and means an average molecular weight obtained by averaging the molecular weights of component molecular species of a polymer compound having a molecular weight distribution in terms of weight fraction.

The g-AAS and g-ABS may include 50 to 60% by weight of rubber and the rest of the SAN resin, and may have a core-shell shape. The g-AAS and g-ABS can be obtained by graft emulsion polymerization of a rubbery polymer having a diameter of 0.3 μm. In the g-AAS and g-ABS, the core portion of the center may be made of rubber, and the shell portion surrounding the surface of the core may be made of SAN resin.

The ethylene/alkyl (meth)acrylate may be represented by Formula 1 below.

Formula 1:

In Formula 1, R1 is hydrogen or a methyl group, and in Formula 1, R2 is an alkyl group of C1 to C12, which is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl group or isobutyl group, and in the above formula (1), m and n are degrees of polymerization, and the ratio of m and n is 300:1 to 10:90.

The ethylene/alkyl (meth)acrylate may be a copolymer mixture of at least one of random, block, multiblock and graft copolymers.

The injection molding ABS ALLOY material may have a melt index (MI) of 4.5 to 8.0 g/10min.

Like the injection HIPS material, if the flow index of the injection ABS ALLOY material is too low, injection molding may be difficult. However, when the flow index is too high, mechanical properties such as tensile strength and impact strength may be deteriorated.

The injection molding ABS ALLOY material according to the present invention may have a tensile strength of 400 to 520 kgf/cm ² , an impact strength of 18 to 30 kgf cm/cm, and a flexural modulus of 18000 to 26000 kgf/cm ² .

When the tensile strength is low, deformation or cracking may occur during the assembly process. However, when the tensile strength is too high, the fluidity may be lowered and the productivity may be lowered.

When the impact strength is low, there is a concern that cracks may occur in the hook portion for assembly. However, when the impact strength is too high, the fluidity is lowered similarly to the tensile strength, and productivity may be lowered.

When the flexural modulus is low, deformation due to load on the substrate may occur. However, when the flexural modulus is too high, cracks may occur at the hook portion for assembly.

The injection molding ABS ALLOY material according to the present invention may have a heat deflection temperature (HDT) of 75 to 90 ° C under a load of 1.82 kg.

When the heat distortion temperature is low, there is a concern that deformation may occur during the high-temperature assembly process. However, if the heat deflection temperature is too high, the fluidity may decrease and productivity may decrease.

Next, an injection-molded HIPS material for home appliances and an injection-molded ABS ALLOY material for home appliances according to another aspect of the present invention will be described.

An injection HIPS material for home appliances according to an example of the present invention is an injection HIPS material composition for home appliances, including a chemical resistant HIPS material and a high flow HIPS material, based on 100 parts by weight of the injection HIPS material, a chemical resistant HIPS material 45 to 65 parts by weight and 35 to 55 parts by weight of a high flow HIPS material, and a melt index (MI) may be 6.0 to 9.5 g/10min.

In addition, the injection-molded HIPS material for home appliances according to an example of the present invention may have a tensile strength of 180 to 300 kgf/cm ² , an impact strength of 7 to 16 kgf cm/cm, and a flexural modulus of 16000 to 24000 kgf/cm ² .

In addition, the injection-molded HIPS material for home appliances according to an example of the present invention may have a heat deflection temperature (HDT) of 72 to 85° C. under a load of 1.82 kg.

The injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention is SAN (Styrene-Acrylonitrile) resin, g-AAS (acrylonitrile-polybutylacrylic acid-styrene copolymer resin), g-ABS (acrylonitrile) -Butadiene-styrene copolymer resin) and ethylene / alkyl (meth) acrylate as an injection ABS ALLOY material composition for home appliances, based on 100 parts by weight of injection ABS ALLOY material, SAN resin 65 to 85 parts by weight, g -AAS 10 to 20 parts by weight, g-ABS 5 to 15 parts by weight and ethylene / alkyl (meth) acrylate 3 to 6 parts by weight, tensile strength is 400 to 520 kgf / cm ² And impact strength is 18 to It may be 30 kgf·cm/cm, and the flexural modulus may be 18000 to 26000 kgf/cm ² .

In addition, the injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention may have a heat deflection temperature (HDT) of 75 to 90 ° C. under a load of 1.82 kg.

In addition, the injection molding ABS ALLOY material for home appliances according to an embodiment of the present invention may have a melt index (MI) of 4.5 to 8.0 g/10min.

The injection-molded ABS ALLOY material and the injection-molded HIPS material can be applied to all home appliances that require sufficient strength and chemical resistance, such as air conditioners and washing machines.

Hereinafter, Examples and Comparative Examples are described to aid in understanding the present invention. However, the following description only corresponds to an example of the contents and effects of the present invention, and the scope and effects of the present invention are not necessarily limited thereto.

{Example}

For the various injection HIPS material compositional contents shown in Table 1 below, after adding a small amount of antioxidant, they were prepared in the form of pellets at 220 ° C. After drying the prepared pellets at 75 ° C. for 2 hours, specimens were prepared by injection molding at a molding temperature of 230 ° C. and a mold temperature of 60 ° C. in a small injection machine.

division Injection HIPS material composition
(parts by weight) Injection HIPS material Chemical resistant HIPS material High flow HIPS material Generic HIPS material Example 1 100 50 50 - Example 2 100 60 40 - Comparative Example 1 100 40 60 - Comparative Example 2 100 70 30 - Comparative Example 3 100 10 - 90 Comparative Example 4 100 - - 100

Table 2 below shows flow index, tensile strength, impact strength, flexural modulus, heat deflection temperature, environmental stress cracking (ESC) evaluation results, and temperature cycle evaluation results.

Melt Index (MI) was measured at 200° C. and a load of 5 kg based on the ASTM D1238 standard.

Tensile strength, based on the ASTM D638 standard, was measured at room temperature for a specimen having a thickness of 3.2 mm under a tensile rate of 50 mm/min.

Impact strength, based on the ASTM D256 standard, was measured at room temperature with a specimen having a thickness of 3.2 mm.

The flexural modulus was measured for a specimen having a thickness of 6.4 mm at room temperature at a test speed of 5 mm/min, based on the ASTM D790 standard.

Heat deflection temperature (HDT) was measured under a load of 1.82 kg based on the ASTM D648 standard.

The environmental stress cracking evaluation results are measured by placing a specimen on a strain 1% jig with a band strip test device conforming to the ISO-4599 standard, applying gauze, and visually checking whether cracks occur 24 hours after applying soybean oil. did.

In the environmental stress cracking evaluation results in Table 2 below, 'O' means the case where cracks occur, and 'X' means the case where no cracks occur. When cracks do not occur, chemical resistance can be evaluated as excellent.

The temperature cycle evaluation results were measured by visually checking whether cracks occurred after 5 cycles, in which the finished refrigerator product was placed in the chamber and stored for 17 hours at a temperature range of -30 to 70 ° C.

In the temperature cycle evaluation results of Table 2 below, 'O' means a case where a crack occurs, and 'X' means a case where a crack does not occur. When cracks do not occur, it can be evaluated that sufficient physical properties have been secured as an inner refrigerator.

division liquidity index
(g/10min) tensile strength
(kgf/cm ² ) impact strength
(kgf cm/cm) Flexural modulus
(kgf/cm ² ) heat deflection temperature
(℃) Environmental stress cracking evaluation result Temperature cycle evaluation result Example 1 9.5 225 10 19500 75 X X Example 2 7.5 235 10 20500 77 X X Comparative Example 1 11.6 245 9 22000 78 O O Comparative Example 2 5.5 220 11 18500 74 X X Comparative Example 3 5.1 250 11 21500 80 O O Comparative Example 4 5.5 265 12 22500 81 O O

Referring to Table 2, Examples 1 and 2 satisfied all of the component ranges presented in the present invention. Therefore, Examples 1 and 2 had a flow index of 6.0 to 9.5 g/10 min, a tensile strength of 180 to 300 kgf/cm ² , an impact strength of 7 to 16 kgf cm/cm, a flexural modulus of 16000 to 24000 kgf/cm ² , and thermal deformation. Temperatures of 72 to 85 ° C were all satisfied. In addition, Examples 1 and 2 did not generate cracks as a result of environmental stress cracking evaluation and temperature cycle evaluation. That is, Examples 1 and 2 were able to secure sufficient physical properties as an inner refrigerator while simultaneously satisfying high fluidity and excellent chemical resistance.

However, in Comparative Example 1, the chemical resistant HIPS material content was low, and cracks occurred as a result of environmental stress cracking evaluation, and cracks occurred as a result of temperature cycle evaluation. That is, Comparative Example 1 was inferior in chemical resistance and could not be evaluated as having sufficient physical properties as an inner refrigerator.

Comparative Example 2 did not satisfy the flow index of 6.0 to 9.5 g/10 min due to the low content of the high flow HIPS material. That is, Comparative Example 2 could not secure sufficient fluidity for injection molding.

Comparative Examples 3 and 4 did not satisfy both the content of the chemical resistant HIPS material and the high flow HIPS material. Therefore, Comparative Examples 3 and 4 generated cracks as a result of environmental stress cracking evaluation, and did not satisfy the flow index of 6.0 to 9.5 g/10 min. In Comparative Examples 3 and 4, cracks occurred as a result of temperature cycle evaluation. That is, Comparative Examples 3 and 4 were inferior in chemical resistance, could not secure sufficient fluidity for injection molding, and could not be evaluated as having sufficient physical properties as an inner refrigerator.

For the composition contents of the various injection molding ABS ALLOY materials shown in Table 3 below, after adding a small amount of antioxidant, they were prepared in the form of pellets at 220 ° C. After drying the prepared pellets at 80 ° C. for 2 hours, specimens were prepared by injection molding at a molding temperature of 240 ° C. and a mold temperature of 60 ° C. in a small injection machine.

In Table 3 below, SAN1 is a SAN having an acrylonitrile content of 20% by weight, and SAN2 is a SAN having an acrylonitrile content of 27% by weight.

division Injection HIPS material composition
(parts by weight) Injection ABS ALLOY material SAN1 SAN2 g-AAS g-ABS Ethylene/alkyl(meth)acrylates Example 3 100 75 - 12 10 3 Example 4 100 77 - 10 10 3 Comparative Example 5 100 75 - - 25 - Comparative Example 6 100 75 - 8 17 - Comparative Example 7 100 74 - 23 - 3 Comparative Example 8 100 - 75 15 10 -

Table 4 below shows flow index, tensile strength, impact strength, flexural modulus, heat deflection temperature, environmental stress cracking (ESC) evaluation results, and temperature cycle evaluation results.

The measurement method of the flow index, tensile strength, impact strength, flexural modulus, heat deflection temperature, environmental stress crack evaluation result and temperature cycle evaluation result of the injection molding ABS ALLOY material specimen is the same as the measurement method of the injection molding HIPS material specimen.

division liquidity index
(g/10min) tensile strength
(kgf/cm ² ) impact strength
(kgf cm/cm) Flexural modulus
(kgf/cm ² ) heat deflection temperature
(℃) Environmental stress cracking evaluation result Temperature cycle evaluation result Example 3 5.6 450 24 22500 82 X X Example 4 6.0 460 25 23000 83 X X Comparative Example 5 5.7 440 27 22000 82 O O Comparative Example 6 5.6 460 25 23000 83 O O Comparative Example 7 4.5 470 17 24000 84 X X Comparative Example 8 5.6 450 24 22500 82 O O

Referring to Table 4, Examples 3 and 4 satisfied all of the component ranges presented in the present invention. Therefore, Examples 3 and 4 had a flow index of 4.5 to 8.0 g/10 min, tensile strength of 400 to 520 kgf/cm ² , impact strength of 18 to 30 kgf cm/cm, flexural modulus of 18000 to 26000 kgf/cm ² and thermal deformation. Temperatures of 75 to 90 ° C were all satisfied. In addition, Examples 3 and 4 did not generate cracks as a result of environmental stress cracking evaluation and temperature cycle evaluation. That is, Examples 3 and 4 were able to secure sufficient physical properties as an inner refrigerator while simultaneously satisfying high fluidity and excellent chemical resistance.

However, in Comparative Example 5, g-AAS was not added, and cracks occurred as a result of environmental stress cracking evaluation, and cracks occurred as a result of temperature cycle evaluation. That is, Comparative Example 5 was inferior in chemical resistance.

In Comparative Example 6, the g-AAS content was less than 10 parts by weight. Therefore, in Comparative Example 6, cracks occurred as a result of environmental stress cracking evaluation, and cracks occurred as a result of temperature cycle evaluation. That is, Comparative Example 6 was inferior in chemical resistance.

In Comparative Example 7, g-ABS was not added, and the impact strength did not satisfy 18 to 30 kgf cm/cm. That is, in Comparative Example 7, despite being an injection molding ABS ALLOY material, it was difficult to secure sufficient strength.

In Comparative Example 8, SAN having a low acrylonitrile content was used, and cracks occurred as a result of environmental stress cracking evaluation, and cracks occurred as a result of temperature cycle evaluation. That is, Comparative Example 8 was inferior in chemical resistance.

4 is a photograph showing the environmental stress cracking (ESC) evaluation result for Comparative Example 6, and FIG. 5 is a photograph showing the environmental stress cracking evaluation result for Example 4.

Referring to FIGS. 4 and 5 , in Comparative Example 6, cracks occurred as a result of environmental stress cracking evaluation, and in Example 4, cracks did not occur. That is, it was confirmed that cracks may occur due to vegetable oil when the chemical resistance is poor.

Claims (20)

External appearance of the refrigerator (Cabinet Frame);
A liner that isolates the inside of the refrigerator and the insulation; and
Including a heat insulating material provided between the outer case and the inner case,
The inner case includes an injection high impact polystyrene (HIPS) material or an injection acrylonitrile butadiene styrene (ABS) ALLOY material. The method of claim 1,
The inner injury is composed of an upper part, a side part and a lower part,
The upper and side parts of the inner garment include an injection HIPS material,
The lower portion of the inner case includes an injection molding ABS ALLOY material. The method of claim 1,
The inner box has a thickness of 1 to 2.5 mm, the refrigerator. The method of claim 1,
The injection HIPS material,
Based on 100 parts by weight of the injected HIPS material,
A refrigerator comprising 45 to 65 parts by weight of a chemical resistant HIPS material and 35 to 55 parts by weight of a high flow HIPS material. The method of claim 4,
The chemical-resistant HIPS material includes 9.5 to 12% by weight of rubber and the remainder PS (Polystyrene),
The average particle diameter of the rubber is 6.0 to 8.5 μm, a refrigerator. The method of claim 4,
The high-flow HIPS material includes 7.0 to 9.0% by weight of rubber and the remainder PS (Polystyrene),
The average particle diameter of the rubber is 1.2 to 1.8㎛, the refrigerator. The method of claim 1,
The injection HIPS material has a melt index (MI) of 6.0 to 9.5 g/10min, a refrigerator. The method of claim 1,
The injection molding ABS ALLOY material,
Based on 100 parts by weight of injection molding ABS ALLOY material,
SAN (Styrene-Acrylonitrile) resin 65 to 85 parts by weight, g-AAS (acrylonitrile-polybutylacrylic acid-styrene copolymer resin) 10 to 20 parts by weight, g-ABS (acrylonitrile-butadiene-styrene copolymer resin ) 5 to 15 parts by weight and 3 to 6 parts by weight of ethylene / alkyl (meth) acrylate, a refrigerator. The method of claim 8,
The SAN resin contains 25 to 29% by weight of acrylonitrile and the remainder polystyrene (PS), and has a weight average molecular weight of 120,000 to 160,000, a refrigerator. The method of claim 8,
The g-AAS and g-ABS contain 50 to 60% by weight of rubber and the rest of the SAN resin, and have a core-shell shape. The method of claim 8,
The ethylene / alkyl (meth) acrylate is represented by Formula 1 below, a refrigerator:
Formula 1:

(In Formula 1, R1 is hydrogen or a methyl group,
In Formula 1, R2 is a C1 to C12 alkyl group, which is hydrogen, methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, t-butyl or isobutyl,
In Formula 1, m and n are degrees of polymerization, and the ratio of m and n is 300:1 to 10:90). The method of claim 1,
The injection molding ABS ALLOY material has a melt index (MI) of 4.5 to 8.0 g/10min, a refrigerator. An injection HIPS material composition for home appliances, including a chemical resistant HIPS material and a high flow HIPS material,
Based on 100 parts by weight of the injected HIPS material,
45 to 65 parts by weight of a chemical resistant HIPS material and 35 to 55 parts by weight of a high flow HIPS material,
An injection HIPS material for home appliances having a melt index (MI) of 6.0 to 9.5 g/10min. The method of claim 13,
A tensile strength of 180 to 300 kgf / cm ² and an impact strength of 7 to 16 kgf cm / cm, an injection HIPS material for home appliances. The method of claim 13,
An injection-molded HIPS material for home appliances having a flexural modulus of 16000 to 24000 kgf/cm ² . The method of claim 13,
An injection-molded HIPS material for home appliances with a heat deflection temperature (HDT) of 72 to 85 ° C at a load of 1.82 kg. SAN (Styrene-Acrylonitrile) resin, g-AAS (acrylonitrile-polybutylacrylic acid-styrene copolymer resin), g-ABS (acrylonitrile-butadiene-styrene copolymer resin) and ethylene/alkyl (meth)acrylates As an injection molding ABS ALLOY material composition for home appliances comprising a,
Based on 100 parts by weight of injection molding ABS ALLOY material,
65 to 85 parts by weight of SAN resin, 10 to 20 parts by weight of g-AAS, 5 to 15 parts by weight of g-ABS, and 3 to 6 parts by weight of ethylene/alkyl (meth)acrylate,
An injection-molded ABS ALLOY material for home appliances having a tensile strength of 400 to 520 kgf/cm ² and an impact strength of 18 to 30 kgf cm/cm. The method of claim 17
An injection-molded ABS ALLOY material for home appliances with a flexural modulus of 18000 to 26000 kgf/cm ² . The method of claim 17
An injection-molded ABS ALLOY material for home appliances with a heat deflection temperature (HDT) of 75 to 90 °C at a load of 1.82 kg. The method of claim 17
An injection molding ABS ALLOY material for home appliances with a melt index (MI) of 4.5 to 8.0 g/10min.

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