JP2593574B2 - Insulation box - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a heat insulating box using a urethane foam heat insulating material.

[Prior Art] First, a general configuration and a manufacturing method of a refrigerator box, which is a kind of a heat insulating box, are described in, for example, a publication (Polyurethane Resin Handbook, P238-243,248-250, published by Nikkan Kogyo Shimbun, plastics market and products). Design Electric / Electronic Equipment The explanation is based on those shown in Plastic Age Co., Ltd., pp. 58-67. FIG. 1 is a perspective view of a general refrigerator box, and FIG. 2 is a sectional view of the refrigerator box. In the figure, (1) is an outer box, (2) is an inner box, and (3) is a urethane foam heat insulating material. That is, the outer box (1) is manufactured by, for example, forming a painted or coated steel sheet into an outer box shape (a gate type or a reverse gate type). Next, the inner box (2) and the outer box (1) formed in a predetermined shape are combined, and a urethane stock solution which is a raw material of the urethane foam insulation material (3) is provided between the inner box (2) and the outer box (1). The outer box (1) and the inner box (2) are joined and integrated by the urethane foam heat insulating material (3), so that the urethane foam heat insulator (3) plays the role of heat insulator and structure. Used as a strength member as a body. The outer box and the inner box may be made of the same material depending on the purpose of use.

At the time of urethane foaming, the heat generated during the curing reaction of the urethane causes a high temperature of 60 ° C. or more at the center of the urethane foam heat insulating material (3). For this reason, after the urethane curing reaction, the urethane foam heat insulating material (3) shrinks during cooling, and shrinkage stress is generated. This collecting stress causes distortion in the urethane foam heat insulating material (3) and the inner box (2), and if the strength of the inner box material is insufficient, a whitening phenomenon and cracks occur in the inner box. Therefore, as an inner box material, the moldability is good, the adhesion to the urethane foam insulation material (3) is good, the stress resistance to low-temperature shrinkage is excellent, and the impact resistance to the falling of an article in a refrigerator or It is required to have excellent chemical resistance against contamination of edible oils, seasonings and the like in refrigerators, and ABS resin (acrylonitrile-butadiene-styrene terpolymer) and styrene resin containing butadiene rubber are required to satisfy these requirements. And vinyl chloride resin.

On the other hand, as a foaming agent for the urethane foam insulation material (3),
CFC-11 (CCl ₃ F), which is a fluorocarbon, is most commonly used in terms of heat insulation, toxicity, safety, workability, and cost. The CFC-11 is mixed in a liquid state with the urethane raw material, and is vaporized by the heat of reaction of the urethane resin during urethane foaming to form fine cells. This CFC-11 in the cell
Diffuses out of the foam cell over time. For this reason, the inner box (2) is affected by CFC-11 due to diffusion from inside the cell after foaming as well as during the injection of the urethane raw material.
The styrene resin currently used for the inner box (2) is CF
It has low resistance to C-11 and requires a protective film or a protective coat so that it does not come into direct contact with the foam material (3). Further, the vinyl chloride resin is less susceptible to the influence of CFC-11, but has a drawback that it has low heat resistance, is deformed by heat during the reaction of the heat insulating material (3), has a low impact strength, and is easily cracked. ABS resin is a material having an excellent balance of moldability, stress relaxation at low temperature shrinkage, impact resistance, solvent resistance, CFC-11 resistance, and the like, and is currently most widely used.

Meanwhile, as a cause of the emission of CFC-11 and other CFCs that deplete the ozone layer in the stratosphere, international regulations on the production and consumption of CFCs have begun. CFC-11 is
Since it is contained in these regulated substances, it becomes difficult to use urethane insulation as a foaming agent, and an alternative foaming agent is required. As alternative foaming agents for CFC-11, HCFC-123 (CHCl ₂ CF ₃ ) and HCFC-141b (CH ₃ CCl ₂ ) which are similar to CFC-11 in physical properties (boiling point, latent heat of evaporation, etc.)
F) there.

[Problems to be Solved by the Invention] However, HCFC-123 and HCFC-141b have higher solubility in a polymer material than CFC-11, and are not suitable for box material such as butadiene rubber-containing styrene resin and ABS resin. Swelling and dissolving ability is large, and replacement of these foaming agents leads to reduction in strength, breakage, and poor appearance of the box. When HCFC-123 and HCFC-141b are used as the foaming agent of the urethane foam heat insulating material (3), the ABC resin conventionally used for the box body includes:
There is a problem that the attack of the foaming agent is large and cracks occur in the box. For this reason, the thickness of the box material is made very thick, or a film having excellent resistance to HCFC-123 and HCFC-141b is laminated, but the thickness of the box material is increased. It is affected by HCFC over time, and in the long term, the quality of refrigerator boxes and the like deteriorates, which is not an essential solution. Further, when the plate thickness is increased, there are disadvantages that the molding time is increased and productivity is reduced, and the weight of the material is increased and the weight of the refrigerator box is increased. In addition, laminates of materials with excellent HCFC resistance
Although it has the effect of preventing the attack from HCFC with the minimum necessary thickness, it requires a separate process for laminating, resulting in an increase in cost and being affected by HCFC because the cutout part of the box is not laminated Therefore, there is a problem that protection for preventing the attack of the HCFC is required, which complicates the production, and that the material is difficult to recycle because it is composed of different materials.

It is also common practice to mix fillers such as glass fiber (GF) and carbon fiber (CF) to improve the mechanical properties of the material, but both GF and CF have a fiber diameter of 5%. ~ 20μm and length is 100μm ~ several mm and shape is big,
There is a drawback that the surface smoothness and surface design of the molded article are significantly reduced. It also has the disadvantage that the formability of the material is reduced by the fibers.

The present invention has been made in order to solve such a problem, and can be obtained by using a conventional manufacturing facility.
An object of the present invention is to provide a heat insulating box excellent in strength, appearance and design even when a urethane foam heat insulating material using at least one of -123 and HCFC-141b as a foaming agent is used.

[Means for Solving the Problems] The heat insulating box of the present invention comprises HCFC-123 and HCFC-141.
b) a urethane foam insulating material using at least one of b as a foaming agent, and a box in contact with the heat insulating material, wherein the box is made of a styrene-acrylonitrile copolymer containing 5 to 50% by weight of an alkyl acrylate rubber. It is formed of a styrene-acrylonitrile-butadiene terpolymer blended in an amount of 5% by weight or more.

Further, a urethane foam heat insulating material using at least one of HCFC-123 and HCFC-141b as a foaming agent, and a box in contact with the heat insulating material, wherein the box contains 0.25 to 25% by weight of an alkyl acrylate rubber. Of styrene-acrylonitrile-butadiene terpolymer.

[Operation] The styrene-acrylonitrile resin containing the alkyl acrylate rubber used in the present invention is a known material,
Absorbs HCFC-123 and HCFC-141b and swells. In the present invention, the solvent resistance of the styrene-acrylonitrile-butadiene terpolymer (ABS resin) blended with the above-mentioned alkyl acrylate rubber greatly changes depending on the copolymerization ratio of acrylonitrile as a constituent.
When acrylonitrile is 40 parts by weight or less with respect to 0 parts by weight, acrylonitrile is dissolved in HCFC-123 (unlimited swelling) and HCFC-141 is dissolved.
Swells against b. Thus, the styrene-acrylonitrile resin and the ABS resin each containing the alkyl acrylate rubber used in the present invention alone are not necessarily preferable in terms of the solvent resistance to HCFC-123 and HCFC-141b, but are not necessarily preferable. Is a blend of the two resins in the mixing ratio shown in the claims, to form a box body in contact with a urethane foam insulation material using at least one of HCFC-123 and HCFC-141b as a foaming agent, When a test (heat cycle test) of repeatedly maintaining the high-temperature and low-temperature conditions on the heat-insulating box body using the box body was performed, it was possible to prevent cracks from being generated in the box body in contact with the urethane foam insulating material. In addition, styrene-acrylonitrile resin containing alkyl acrylate rubber has a molding temperature range close to that of ABS resin in sheet extrusion molding and sheet vacuum molding, and has a stable tensile strength over a wide range in tensile behavior at high temperatures of 100 ° C or higher. And elongation characteristics,
Even if it is blended with the ABS resin, the above-mentioned box can be molded without impairing the excellent vacuum moldability of the ABS resin. Further, since the styrene-acrylonitrile resin containing the alkyl acrylate rubber is milky white, even if it is blended with the ABS resin, the coloring property comparable to the ABS resin can be obtained without inhibiting the coloring property of the ABS resin. Styrene-acrylonitrile resin containing an alkyl acrylate rubber has light resistance,
The ABS resin blended with a styrene-acrylonitrile resin containing an alkyl acrylate rubber has excellent long-term stability because of its excellent weather resistance and heat-resistant oxidative deterioration under a natural environment. Thus, the alkyl acrylate rubber component is
By using an ABS resin containing 5% by weight or more of a styrene-acrylonitrile resin containing 50% by weight in a box, and containing an alkyl acrylate rubber in an amount of 0.25 to 25% by weight.
The intended purpose can be achieved by using the ABS resin for the box.

[Examples] As the styrene-acrylonitrile-butadiene terpolymer (ABS resin) in which the alkyl acrylate rubber component according to the present invention is blended, the rubber component is a butadiene, a styrene-butadiene copolymer, an acrylonitrile-butadiene. Styrene as a glassy polymer composed of at least one mixture of copolymers and the like, in which these rubber components are dispersed in particles, and a part of which is chemically bonded to these rubber dispersed particles. , A continuous phase obtained by polymerizing at least one kind of monomer such as P-methylstyrene, α-methylstyrene, acrylonitrile, alkyl acrylate vinyl monomer, acrylate vinyl monomer, N-phenylmaleimide, etc. Is what is done.

In the styrene-acrylonitrile resin containing the alkyl acrylate rubber component according to the present invention, the rubber component is methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl. Acrylate, 2-methylpentyl acrylate, 2-ethylhexyl acrylate, n
A mixture of one or more of octyl acrylate and the like as a crosslinking agent, divinylbenzene, alkylidene norbornene, alkenyl norbornene, dicyclopentadiene, methylcyclopentadiene, butadiene,
A polymer made from a vinyl compound having two or more unsaturated bonds in one molecule, such as isoprene, in which a polymer is dispersed. As a glassy polymer having a chemically bonded part, at least one of styrene, P-methylstyrene, α-methylstyrene, acrylonitrile, alkyl acrylate-based vinyl monomer, acrylate-based vinyl monomer, N-phenylmaleimide, etc. It is composed of a continuous phase obtained by polymerizing monomers. That is, as the styrene-acrylonitrile resin containing the alkyl acrylate rubber component, for example, generally, ABS resin or AAS
Weatherfill, called resin, brand name, manufactured by Ube Sycon Co., Ltd., GELOY brand name, manufactured by General Electric,
Diamond rack A (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) or the like can be used. The content of the alkyl acrylate rubber of the styrene-acrylonitrile resin containing the alkyl acrylate rubber component is used in the range of 5 to 50% by weight, preferably 15 to 50% by weight. If the content is less than 5% by weight, the effect of the composition cannot be obtained, and when a urethane heat insulating material using HCFC as a foaming agent is used, a fracture phenomenon such as a crack occurs in the inner box. On the other hand, if the content exceeds 50% by weight, a large anisotropy occurs in the impact strength of the ABS resin compounded, and the impact resistance of the molded product is reduced. There is a drawback that lowers. When the styrene-acrylonitrile copolymer containing the alkyl acrylate rubber component in an amount of 5 to 50% by weight is contained in an amount of 5% by weight or more, preferably 5 to 50% by weight, the ABS resin forming the box of the present invention can be obtained. Can be If the amount is less than 5% by weight, no effect can be obtained. The ABS resin forming the box of the present invention can be obtained by containing the alkyl acrylate rubber component in an amount of 0.25 to 25% by weight of the ABS resin forming the box.

Example 1 A styrene-acrylonitrile resin containing an alkyl acrylate rubber was used as GELOY-GY1120 (trade name, Genera) using ABS resin EX200 (trade name, manufactured by Ube Sycon Co., Ltd.).
l Electric Corporation was used. G to the above ABS resin pellet
ELOY-GY1120 pellets were blended so as to have the blending amounts shown in Table 1, and were melt-mixed using a kneading extruder, which is a known method, to obtain pellets. Next, a sheet was formed using a sheet extruder having a coat hanger die, and the inner box of a refrigerator as a heat insulating box was formed using the sheet using a vacuum forming machine. This was foamed and molded using a urethane stock solution using HCFC-123 or HCFC-141b as a foaming agent, and the refrigerator box shown in FIG. 1 was assembled. A heat cycle test was performed. The results shown in Table 1 were obtained. The heat cycle test is a result of visually observing the state after 10 cycles of 12 hours at -20 ° C and 12 hours at + 50 ° C.

Example 2 GELOY-XP1001 (trade name, Genera) was used as a styrene-acrylonitrile resin containing an alkyl acrylate rubber using EX200 (trade name, manufactured by Ube Saikon Co., Ltd.) of ABS resin.
l Electric Corporation was used. G to the above ABS resin pellet
ELOY-XP1001 was blended so as to have the blending amount shown in Table 2,
The mixture was melt-mixed using a kneading extruder, which is a known method, to obtain pellets. Next, an inner box was manufactured in the same manner as in Example 1, and an evaluation test of the refrigerator was performed. Table 2 shows the results.

Example 3 Weatherfil MD120 (trade name) was used as a styrene-acrylonitrile resin containing an alkyl acrylate rubber, using ABS resin EX200 (trade name, manufactured by Ube Saikon Co., Ltd.).
Ube Saikon Co., Ltd. was used. Weatherfill MD120 was blended with the ABS resin pellets so as to have the blending amount shown in Table 3, and was melt-mixed using a kneading extruder, which is a known method, to obtain pellets. Next, an inner box was manufactured in the same manner as in Example 1, and an evaluation test of the refrigerator was performed. Table 3 shows the results.

Example 4 Using EX200 (trade name, manufactured by Ube Sycon Co., Ltd.) of ABS resin, Dialac A-S710 (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) was used as a styrene-acrylonitrile resin containing an alkyl acrylate rubber. used. Diarac A-S710 was blended with the ABS resin pellets so as to have a blending amount shown in Table 4, and melt-mixed using a kneading extruder, which is a known method, to obtain pellets. next, An inner box was manufactured in the same manner as in Example 1, and an evaluation test of the refrigerator was performed. Table 4 shows the results.

Comparative Example 1 For comparison, Table 5 shows that the inner box was manufactured using GSW, GSE, EX200, EX201, and EX245, which are conventional ABS resins for extrusion molding, all manufactured by Ube Sycon Corporation. The result when evaluating as a refrigerator like 1 was shown. HCFC-123 and HCFC-141b are emitted for all ABS resins. In the heat cycle test used for the foaming agent, cracks and the like occur in the inner box, which is unsuitable as a refrigerator inner box material.

As can be seen from the above results, the heat-insulating box of the embodiment of the present invention can be put to practical use, and the intended purpose has been achieved.

In the above-described embodiment, a refrigerator box was described as an embodiment of the heat insulating box of the present invention. However, the present invention is not limited to this. It goes without saying that the same effect as in the above embodiment can be obtained also in the case of a urethane foam heat insulating material using 123 and HCFC-141b as a foaming agent.

Further, in the above-described embodiment, the above-described composition is used only for the inner box of the heat insulating box, but the same effect is exhibited when used for the outer box.

[Effects of the Invention] As described above, the present invention provides HCFC-123 and HCFC-1
41b, comprising a urethane foam heat insulating material using at least one of the foaming agents as a foaming agent and a box in contact with the heat insulating material, wherein the box is made of a styrene-acrylonitrile copolymer containing 5 to 50% by weight of an alkyl acrylate rubber. By using a styrene-acrylonitrile-butadiene terpolymer blended at 5% by weight or more, HCFC-123
Even if a urethane foam heat insulating material using at least one of HCFC-141b as a foaming agent is used, a box for heat insulation excellent in strength, appearance and design can be obtained using conventional production equipment. Further, a urethane foam heat insulating material using at least one of HCFC-123 and HCFC-141b as a foaming agent, and a box in contact with the heat insulating material, wherein the box contains 0.25 to 25% by weight of an alkyl acrylate rubber. HCFC-123 and HCFC-1 by using the styrene-acrylonitrile-butadiene terpolymer.
Even if a urethane foam heat insulating material using at least one of 41b as a foaming agent is used, a heat insulating box excellent in strength, appearance and design can be obtained using conventional production equipment.

[Brief description of the drawings]

FIG. 1 is a perspective view of a general refrigerator box, and FIG. 2 is a sectional view. In the figure, (1) is an outer box, (2) is an inner box, and (3) is a urethane foam heat insulating material. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuing from the front page (72) Inventor Kosuke Shimamura 3-18-1, Oka, Shizuoka-shi, Shizuoka Mitsubishi Electric Corporation Shizuoka Works (72) Inventor Junhisa Akahoshi 525-14 Oki Obe, Ube-shi, Yamaguchi Prefecture Ube Sicon Ube Factory (72) Inventor Hiroshi Igarashi 525-14 Oki Obe, Oji, Ube City, Yamaguchi Prefecture Ube Factory (72) Inventor Koji Hirata 525-14 Oki Ube, Ube City, Ube City, Yamaguchi Prefecture Ube Sicon Corporation Ube Inside the factory (56) References JP-A-2-78885 (JP, A) JP-A-55-38404 (JP, A)

Claims (2)

(57) [Claims] 1. A urethane foam heat insulating material using at least one of HCFC-123 and HCFC-141b as a foaming agent, and a box in contact with the heat insulating material. A heat-insulating box made of a styrene-acrylonitrile-butadiene terpolymer containing 5% by weight or more of a styrene-acrylonitrile copolymer containing 5% by weight. 2. A urethane foam insulating material using at least one of HCFC-123 and HCFC-141b as a foaming agent, and a box in contact with the heat insulating material. A heat-insulating box made of a styrene-acrylonitrile-butadiene terpolymer containing 1% by weight.