JPH0476370A - Heat-insulating box - Google Patents

Abstract

PURPOSE:To produce a heat-insulating box which is excellent in strength, appearance, and adaptability to designs and to whose manufacture conventional manufacturing equipment is applicable by forming the product from a foamed polyurethane as heat-insulating material and a terpolymer of styrene-acrylonitrile-butadiene which is put in contact with said heat- insulating material, said heat-insulating material of foamed polyurethane using as a foaming agent at least one kind chosen from HCFC-123 and HCFC-141b and said styrene-acrylonitrile- butadiene terpolymer containing a copolymer of styrene-acrylonitrile in a quantity above a specific amount which contains alkyl acrylate rubber in a quantity in a specific range. CONSTITUTION:In a terpolymer of styrene-acrylonitrile-butadiene (ABS resin) the rubber component is composed of at least one kind of compound material from among butadiene, a copolymer of styrene-acrylonitrile resin containing a rubber component of alkyl acrylate the rubber component consists of a polymer formed from one kind or two or more kinds of compound materials from among, for example, methylacrylate, ethylacrylate, and n- propylacrylate by using as a cross-linking agent a vinyl compound having two or more unsturated bonds in one molecule, such as divinylbenzene, alkylidene norbornene, and alkenyl norboronene. The alkyl acrylate rubber is used in a proportion of 5-50 wt.%, desirably in the range of 15-50 wt.%. The styrene-acrylonitrile copolymer containing 5-50 wt.% of the alkyl acrylate rubber component is used in a proportion of over 5 wt.%, preferably in the range of 5-50 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a heat insulating box using a urethane foam heat insulating material.

[Prior Art] First, the general structure and manufacturing method of a refrigerator box, which is a type of heat insulating box, is described in the publication (Polyurethane Resin Handbook, Nikkan Kogyo Shimbun series P238-243゜248).
~250 and Plastic Market and Product Design Electrical and Electronic Equipment Published by Plastics Age Co., Ltd. P58-67)
The explanation will be based on what is shown in . Fig. 1 is a perspective view of a general refrigerator box, and Fig. 2 is a cross-sectional view of the refrigerator box. It is a foam insulation material. That is, the outer box (1
) is manufactured by forming a painted or coated steel plate into an outer box shape (gate-shaped or reverse-opening type, etc.) 6. Next, the inner box (2) and outer box (1) are formed into a predetermined shape. A urethane stock solution, which is the raw material for the urethane foam insulation material (3), is injected between the inner box (2) and the outer box (1) and then foamed, and the urethane foam insulation material (3) is used to form the outer box (1). ) and the inner box (2) are joined and integrated, and the urethane foam heat insulating material (3) is used as a heat insulating material and as a strength member of the structure. Further, depending on the purpose of use, the outer box and the inner box may be made of the same material.

During urethane foaming, the center of the urethane foam insulation material (3) reaches a high temperature of 60° C. or higher due to heat generated during the urethane curing reaction. Therefore, after the urethane hardening reaction, the urethane foam heat insulating material (3) contracts during cooling, and shrinkage stress is generated. This shrinkage stress causes urethane foam insulation (
3) and the inner box (2), and if the strength of the inner box material is insufficient, whitening or cracks will occur in the inner box. Therefore, it has good moldability as an inner box material.
P made from urethane? ! It has good adhesion with the insulation material (3) and has excellent stress resistance against low-temperature shrinkage, as well as impact resistance against falling items in the refrigerator and chemical resistance against contamination by cooking oil, seasonings, etc. inside the refrigerator. Materials that meet these requirements include ABS resin (acrylonitrile-butadiene-methicine ternary copolymer), butadiene rubber-containing styrene resin, and vinyl chloride resin.

On the other hand, is it made from urethane? ! ! As the foaming agent for the new thermal material (3), CFC-11 (CC13F), which is a fluorocarbon, has insulation properties,
It is most commonly used from the viewpoints of Ij# performance, safety, workability, and cost. This CFC-11 is mixed in liquid form into the urethane raw material, and is vaporized by the reaction heat of the urethane resin during urethane foaming, forming fine cells. This CFC-11 in the cells diffuses out of the foam cells over time.

Therefore, the inner N(2) is affected by CFC-11 due to diffusion from within the cell not only during the injection of the urethane raw material but also after foaming. The styrene resin currently used for the inner box (2) has low resistance to CFC-11 and requires a protective film or protective coat to prevent direct contact with the foam material (3). In addition, vinyl chloride resin is CF
Although it is less susceptible to the effects of C-11, it has the drawbacks of low heat resistance, causing deformation due to the heat generated during the reaction of the heat insulating material (3), and low impact strength, making it easy to break. ABS resin is a material with an excellent balance of moldability, stress relaxation during low-temperature shrinkage, impact resistance, solvent resistance, CFC-11 resistance, etc., and is currently the most widely used material.

Incidentally, the production and consumption of fluorocarbon substances, including CFC-11, has begun to be internationally regulated because the release of fluorocarbons destroys the ozone layer in the stratosphere.

CFC-11 is included in this regulated substance, and it is difficult to use it as a foaming agent for urethane insulation materials, and an alternative foaming agent is required. An alternative blowing agent for CFC-11 is HCFC-123 (CIC
12CF3) and ICPC-141b (CH3CC1
2F).

[The problem that the invention tries to solve! ! g] However, ICFC-123 and HCFC-141b have higher solubility in polymeric materials than CFC-11, and have a greater ability to swell and dissolve in butadiene rubber-containing styrene resin and ABS resin, which are the box materials. Substitution of these foaming agents leads to a decrease in the strength of the box, breakage, and poor appearance.

HCFC-1 as a foaming agent for urethane foam insulation material (3)
23 and ICFC-141b, the ABS resin conventionally used for the box body has a problem in that the attack of the foaming agent is large and cracks occur in the box body. Therefore, the wall thickness of the box material must be made very thick, or I
Films that exhibit excellent resistance to CFC-123 and HCFC-141b are laminated, but even if the thickness of the box material is increased, it will be affected by ICFC over time, and in the long term, refrigerator boxes, etc. 1. This is not an essential solution as it will reduce the quality of the plate.In addition, increasing the plate thickness will lengthen the forming time and reduce productivity, and the weight of the material will increase, increasing the weight of the refrigerator box. There is also a drawback. In addition, laminating materials with excellent HCFC resistance is effective in preventing attacks from ICFC with the minimum necessary thickness, but it requires a separate process for lamination, which increases costs, and the case that there are notches in the box body. Since the parts are not laminated, they are affected by ICFC.
There are problems such as the need for protection to prevent the attack of the metal, which makes the structure complicated, and the fact that it is made of different materials, making it difficult to recycle the 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. It has a large shape with a length of 100 .mu.m to 100 .mu.m and a length of 100 .mu.m, and has the drawback that it significantly reduces the surface smoothness and surface design of the molded product. It also has the disadvantage that the fibers reduce the moldability of the material.

This invention was made to solve this problem, and can be obtained using conventional manufacturing equipment, and ICF
It is an object of the present invention to provide a new heating box that has excellent strength, appearance, and design even when using a urethane foam insulation material using at least one of C-123 and ICPC-141b as a foaming agent.

[Means for Solving the Problems] The heat insulating box of the present invention uses ICFC-123 and HC
Urethane foamed P@insulating material using at least one of PC-141b as a blowing agent, and containing 5% by weight or more of a styrene-acrylonitrile copolymer containing 5 to 50% by weight of alkyl acrylate rubber in contact with this heat insulating material It is equipped with a box made of a styrene-acrylonitrile-butadiene terpolymer.

[Function] The styrene-acrylonitrile resin containing alkyl acrylate rubber used in this invention is a known material,
(CFC-123 and ICFC-141b are absorbed and swells.On the other hand, the solvent resistance of the styrene-acrylonitrile-butadiene terpolymer (ABS resin) used in this invention is determined by the copolymerization ratio of the constituent acrylonitrile. If the amount of acrylonitrile is 40 parts by weight or less for 100 parts by weight of styrene, ICF
Dissolved in C-123 (unlimited swelling) L, , HCFC-
141b. In this way, the styrene-acrylonitrile resin containing the alkyl acrylate rubber used in this invention and the ABS resin alone cannot
Although the solvent resistance to FC-123 and HCFC-141b is not necessarily preferable, the inventors have blended the above resins at the blending ratio shown in the claims,
A box body is formed in contact with a urethane foam insulation material using at least one of the above as a foaming agent, and the heat insulation box body using this box body is subjected to a test (heat cycle test) in which it is repeatedly held in high and low temperature conditions. When I went there, I found that the above urethane P@
It was possible to prevent cracks from forming in the box that came into contact with the new thermal material. In addition, styrene containing alkyl acrylate rubber
Acrylonitrile resin has a molding temperature range close to that of ABS resin in sheet extrusion molding and sheet vacuum forming.
ABS
Even when blended with resin, the excellent vacuum formability of ABS resin is not impaired, and the above-mentioned box can be formed. In addition, styrene-acrylonitrile resin containing alkyl acrylate rubber has a milky white color, so even when blended with ABS resin, it does not inhibit the coloring properties of ABS resin.
Coloring properties comparable to resins can be obtained. In addition, styrene-acrylonitrile resin containing alkyl acrylate rubber,
Styrene containing alkyl acrylate rubber has excellent light resistance, weather resistance in natural environments, and heat oxidation resistance.
ABS resin blended with acrylonitrile resin exhibits excellent long-term stability. Thus, an ABS resin containing 5% by weight or more of styrene-acrylonitrile resin containing 5 to 50% by weight of an alkyl acrylate rubber component is used for the box body. By doing so, the intended purpose can be achieved.

[Example] In the styrene-acrylonitrile-butadiene terpolymer (ABS resin) according to the present invention, the rubber component is at least one of butadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, etc. Styrene, P-methylstyrene, α-methyl is a glassy polymer composed of a mixture of these rubber components dispersed in the form of particles, and a part of which is chemically bonded to these rubber dispersed particles. It is composed of a continuous phase obtained by polymerizing at least one monomer selected from styrene, acrylonitrile, an alkyl acrylate vinyl monomer, an acrylic acid vinyl monomer, N-phenylmaleimide, and the like.

The styrene-acrylonitrile resin containing an alkyl acrylate rubber component according to the present invention is characterized in that the rubber component is methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isoamyl acrylate, n- Xyl acrylate, 2-methylpentyl acrylate, 2-ethylhexyl acrylate, n-
Divinylbenzene, alkylidenenorbornene, alkenylnorboronene, dicyclopentadiene, methylcyclopentadiene, butadiene, isoprene, etc., using one or a mixture of two or more of octyl acrylate etc. as a crosslinking agent. It is made into a polymer using a vinyl compound with unsaturated bonds of A continuous compound obtained by polymerizing at least one monomer selected from styrene, P-methylstyrene, α-methylstyrene, acrylonitrile, alkyl acrylate vinyl monomer, acrylate vinyl monomer, N-phenylmaleimide, etc. It is composed of phases. That is, the styrene-acrylonitrile resin containing the alkyl acrylate rubber component is generally 1, for example, ASA* resin or A
Weatherfill (product name, manufactured by Ube Scicon Co., Ltd.) called AS resin, GELOY (product name, Genera
1 Electric Co., Ltd.), Diarack A (trade name, manufactured by Mitsubishi Rayon Co., Ltd.), etc. can be used.

The amount of the alkyl acrylate rubber in the styrene-acrylonitrile resin containing the alkyl acrylate rubber component is preferably 5 to 50% by weight, preferably 15 to 50% by weight. If the amount is less than 5% by weight, no effect will be obtained, and if a urethane heat insulating material using HCFC as a foaming agent is used, destruction phenomena such as cracks will occur in the inner box. Also,
If it exceeds 50% by weight, a large anisotropy will occur in the impact strength of the blended ABS resin, reducing the impact resistance of the molded product, reducing workability when assembling the insulation box, and reducing the box strength. There are drawbacks to doing so.

The styrene-acrylonitrile copolymer containing 5 to 50% by weight of this alkyl acrylate rubber component is 5 to 50% by weight or more, preferably 5 to 50% by weight. Note that if the amount is less than 5% by weight, no effect will be obtained.

Example I ABSII! ? Fatino EX200 (Product name, Ube Dai: 2
GELOY- is a styrene-acrylonitrile resin containing alkyl acrylate rubber.
GY1120 (product name.

General (manufactured by Electric) was used.

GELOY-GY1120 pellets were blended with the above ABS resin pellets in the amounts shown in Table 1, and melt-mixed using a kneading extruder, which is a known method, to form pellets. First, a coat-hanger die was used. A sheet was formed using a sheet extruder, and this sheet was used to form an inner box of a refrigerator as a heat insulating box using a vacuum forming machine. This was foam-molded using a urethane stock solution using HCFC-123 or ICFC-141b as a foaming agent, and the refrigerator box shown in Figure 1 was assembled.A heat cycle test was conducted, and the results shown in Table 1 were obtained. . The heat cycle test is the result of visual observation of the state after 10 cycles of 12 hours at -20°C and 12 hours at 150°C.

Table 1 General (manufactured by Electric) was used.

GELOY-XPlooI was blended into the above ABS resin pellets in the amounts shown in Table 2, and melt-mixed using a kneading extruder, which is a known method, to form pellets.6 Next, the same method as in Example 1 was carried out. We manufactured an inner box and conducted an evaluation test on the refrigerator.

The results are shown in Table 2.

Table 2 ○: Good Δ: Usable Example 2 GELOY-XP is a styrene-acrylonitrile resin containing alkyl acrylate rubber using ABS resin EX200 (trade name, Ube Scicon Co., Ltd. ml).
looI (product name.

○: Good Δ: Usable Example 3 ABS resin EX200 (product name, Ube Scicon Co., Ltd.)
Weatherfill MD120(
(trade name, Ube Scicon Co., Ltd. II) was used. Above A
Weatherfill MD120 was blended with BS resin pellets in the amounts shown in Table 3, and the mixture was melt-mixed using a kneading extruder, which is a known method, to form pellets.

An inner box was manufactured in the same manner as in Example 1, and an evaluation test of the refrigerator was conducted. The results are shown in Table 3.

Table 3 Example 4 Using ABS resin EX200 (trade name, manufactured by Ube Scicon Co., Ltd.), Dialac A-57 was used as a styrene-acrylonitrile resin containing alkyl acrylate rubber.
10 (trade name, manufactured by Mitsubishi Rayon Co., Ltd.) was used. Dialac A-8710 was blended with the above ABS resin pellets in the amount shown in Table 4, and the mixture was melt-mixed into pellets using a kneading extruder, which is a known method.
Table 4 O: Good Δ: Usable 0: Good Δ: Usable An inner box was manufactured in the same manner as in Example 1, and a refrigerator evaluation test was conducted. The results are shown in Table 4.

Comparative Example] For comparison, Table 5 shows conventional extrusion molding ABS resin Teal Gs%1. asE, EX200. Ex201. EX
245 (all manufactured by Ube Scicon Co., Ltd. II), the inner box was manufactured and evaluated as a refrigerator in the same manner as in Example 1. The results are shown below.

In the case of any ABS resin, ICFC-123, ICF
Announcement of C-141b 5 0: Good, Δ: Usable, R: Crack White: Whitening phenomenon In the heat cycle test used for foaming agents, cracks, etc. occurred in the inner box, making it unsuitable as a material for refrigerator inner boxes.

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

Incidentally, in the above embodiments, the case of a refrigerating box was described as an example of the heat insulating box of the present invention.

It is not limited to this, and the same effect can be obtained even when applied to a heat-retaining warehouse, for example.Mari HCFC-123 and HCFC-1
It goes without saying that the urethane foamed new thermal material using No. 41b as a foaming agent also exhibits the same effects as in the above embodiments.

Further, in the above embodiment, the composition described above was used only for the inner box of the heat insulating box, but the same effect can be obtained even if it is used for the outer box as well.

[Effects of the invention] As explained above, this invention provides ICFC-123 and
A urethane foamed new thermal material using at least one type of ICFC-141b as a blowing agent, and a styrene-acrylonitrile copolymer containing 5 to 50% by weight of alkyl acrylate rubber in contact with this new thermal material, containing 5% by weight or more. By using a face piece made of styrene-acrylonitrile-butadiene terpolymer, II.
CFC-123 and Natsu ICFC-141b 6. Even when using urethane foam insulation with at least one type of foaming agent, we can produce insulation boxes with excellent strength, appearance, and design using conventional manufacturing equipment. can be obtained.

[Brief explanation of the drawing]

Figure w1 also shows the needles of a typical refrigerator box, and figure 2 shows the needles of a typical refrigerator box.
It is a diagram. In the figure, (1) is the outer box, (2) is the inner box, and (3) is the urethane foam insulation material. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Claims] Urethane foam insulation material using at least one of HCFC-123 and HCFC-141b as a foaming agent,
and alkyl acrylate rubber in contact with this insulation material.
Styrene-acrylonitrile containing 5% by weight or more of a styrene-acrylonitrile copolymer containing ~50% by weight
A heat insulating box with a box made of butadiene terpolymer.