JPH11248344A - Insulated boxes and doors for refrigerators and freezers - Google Patents

Abstract

(57) Abstract: The present invention does not use CFC or HCFC as a foaming agent at all, and uses a mixed system of cyclopentane and water as a substitute, thereby reducing urethane loading and heat leakage with high strength. An object of the present invention is to provide a heat-insulating box and a heat-insulating door for a refrigerator and a freezer that can also save energy by reduction. A rigid polyurethane foam obtained by reacting water and a mixed composition having low solubility in cyclopentane as a foaming agent with cyclopentane, a polyol and an isocyanate component in the presence of a catalyst and a foam stabilizer is used as a refrigerator and a freezer. Insulated box and insulated door.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rigid polyurethane foam heat-insulating box and door product using a mixed blowing agent of cyclopentane and water for use in refrigerators and freezers.

[0002]

2. Description of the Related Art Conventionally, a rigid polyurethane foam having closed cells is filled in a heat insulating portion of a refrigerator and a freezer in a space between an outer box and an inner box, and in a heat insulating door portion in a outer iron plate and a space in an inner door wall. Insulation is used. A rigid polyurethane foam is obtained by reacting a polyol component and an isocyanate component in the presence of a foaming agent, a catalyst, and a foam stabilizer. Conventional foaming agents include chlorofluorocarbon (CFC), which has low gas thermal conductivity and is difficult to decompose.
Trichloromonofluoromethane (JP-A-59-84913) has been used for the insulation of refrigerators, but when released into the atmosphere, the ozone layer depletion in the stratosphere and the temperature rise on the ground surface due to the greenhouse effect occur. And alternatives are being selected. At present, 1,1-dichloro-1-monofluoroethane which is a kind of hydrochlorofluorocarbon (HCFC) as an alternative foaming agent (JP-A-3-258823,
Japanese Patent Application Laid-Open No. 7-25978) is used as a heat insulating material for refrigerators, but since the ozone depletion potential is not zero, it is subject to regulation in 2003 and is scheduled to be completely abolished. on the other hand,
Non-fluorocarbon blowing agents with zero ozone depletion potential are hydrocarbon compounds mainly in Europe (Japanese Patent Laid-Open No. 3-152160).
As a result, cyclopentane blowing agents have been used in the field of heat insulation of refrigerators in Japan. However, cyclopentane has a problem that the thermal conductivity of the gas is high and the heat insulation performance is greatly inferior to the conventional foaming agents. In recent years, as the demand for energy has increased, regarding rigid polyurethane foam materials with cyclopentane, urethane consumption has been improved from the standpoint of securing energy supply and demand balance, improving the heat insulation performance by saving energy in response to global warming issues, and protecting the global environment. The importance of the reduction is increasing, and from that point of view, the heat insulating materials for refrigerators and freezers using cyclopentane blowing agent have been entirely expanded, and higher performance is required.

[0003]

Rigid polyurethane foam materials include a polyol and an isocyanate, which are main raw materials, for controlling the chemical structure, a foaming agent for forming cells and water, and a foaming agent for controlling an interface phenomenon, for controlling the physical structure. The catalyst controls the reactivity. The reaction starts when the polyol and the isocyanate are mixed to form a polyurethane foam in which closed cells of a foaming agent are dispersed in the polyurethane resin. Polyurethane foam is required to have particularly high strength as well as heat insulation. These physical properties are considered to be determined by the physical structure of the polyurethane foam, such as the chemical structure and density of the polyurethane resin, the cell diameter and size of the resin skeleton surrounding the bubbles, and the like. The chemical structure of the polyurethane resin depends on the amount of the blowing agent, the amount of water, and the reactivity controlled by the catalyst together with the chemical structures of the raw materials, polyol and isocyanate. The physical structure of polyurethane foam depends not only on the chemical structure and reactivity of the raw materials, but also on physical phenomena such as the generation and growth of bubbles controlled by the foam stabilizer, and particularly the compatibility, reactivity and foaming process of each raw material. Of the reaction solution has an effect. Therefore, in order to improve the performance of the polyurethane foam, the chemical structure and composition of each raw material must be optimized.

[0004] However, the heat insulating material of the box and door of the refrigerator and freezer of the cyclopentane formula is made of conventional CFC, HCF.
Since the heat insulation performance is significantly inferior to the C foaming agent and the fluidity is poor at high density, there is a problem that the heat insulation performance and strength cannot be sufficiently secured unless a large amount of urethane is used.
Furthermore, due to demands for space saving in refrigerators and freezers, urethane foam is hard to flow inside the walls as the space in the cabinet wall is narrowed and the number of boxes and drive wires of a complicated shape is increased. For this reason, the foam is difficult to stretch uniformly, and the overall density of the skin layer and the core layer density are greatly different at the ceiling, bottom, back, handle, and hinge of the refrigerator, and it is difficult to form a uniform foam. Neighboring bubbles are likely to become resinous (double skin) and voids are likely to occur. In addition, since the door portion is also less likely to flow, there is also a problem that the foaming pressure is increased and a large amount of urethane is used, so that urethane foam leaks. In order to meet such a problem, it is necessary to develop a new urethane material that can achieve both low density, high fluidity, and high strength characteristics even with a cyclopentane formulation. In other words, as a result of filling the refrigerator with a low-density, high-strength urethane material of cyclopentane formula, the cost and weight can be reduced with the use of less heat insulating material, and energy savings can be achieved by reducing the amount of heat leakage from high fluidity. It is possible to achieve high-quality refrigerators and other products using cyclopentane blowing agents from the standpoint of global warming and global environmental protection. However, polyurethane foams using cyclopentane foaming agents have a big problem that the saturated vapor pressure is lower than that of conventional foaming agents, so that the pressure in the cell decreases, the shrinkage easily occurs, and the strength decreases. is there. That is, the foam density and the compressive strength are generally in a proportional relationship, and the higher the density, the higher the compressive strength. This is because the higher the foam density, the higher the proportion of the polyurethane resin and the higher the compressive strength of the foam. For example, in order to make the compressive strength 0.1 MPa or more, the whole skin layer density is usually 38 kg / m ³ or more, and it is difficult to achieve both low density and high strength with the current urethane material of cyclopentane formulation. ing. Therefore, in order to mainly secure the strength of the current rigid polyurethane foam of cyclopentane formulation, urethane having a high density of 38 kg / m ³ or more is used, and a large amount of material is filled in the space inside the cabinet wall to produce a heat insulating material. It is carried out. For this reason, high-performance cyclopentane-form urethane is a heat insulating material that can significantly reduce urethane by foam-filling compatible materials with low density, high fluidity, and excellent compressive strength and dimensional stability. Is strongly desired from the standpoint of global environmental protection.

[0005] It is an object of the present invention to fill a urethane heat insulating material of cyclopentane formulation, which can achieve both low density and high strength characteristics, in a rigid polyurethane foam in which a heat insulating box and a door used for refrigerators and freezers are foam-filled. By reducing the amount of filling, the cost and weight are reduced and the compressive strength and dimensional stability are excellent, and because of the high fluidity, energy-saving products with a reduced amount of heat leakage are stably produced with high yield and high performance. Is to provide the body.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have developed a low-density, high-fluidity, and low-density composition required for a cyclopentane formulation to develop a rigid polyurethane foam most suitable for boxes and doors used in refrigerators or freezers. As a specific measure to improve the urethane resin skeleton (cell) strength, a rigid and low-solubility polyol and isocyanate can be used to completely seal the foaming agent in the cell by selecting the solvent and solvent plasticization of the cell. By using a large amount of water to be used in combination with the cyclopentane blowing agent,
As a result of intensive studies on a method of increasing the partial pressure of carbon dioxide in the gas in the cell to increase the pressure in the cell, the following findings were obtained, and the present invention was completed.

That is, the first and second inventions provide a mixed foaming agent of cyclopentane and water in a space inside a cabinet wall of an outer box and an inner box of a refrigerator or a freezer and a space inside an outer door iron plate and an inner door wall. In the heat-insulating box and the heat-insulating door filled with the used rigid polyurethane foam, the heat-insulating box and the foam and the heat-insulating door are separated from the urethane injection port by at least 500 mm or more from the outer surface of the urethane-filled portion.
The overall skin layer density of foam separated by more than 34.5 mm
37.5 kg / m ³ , core layer density 32.5-34.5 kg / m
³ and a rigid polyurethane foam insulation material having a compression strength of 0.15 to 0.2 MPa and a bending strength of 0.4 to 0.5 MPa.

The third and fourth aspects of the present invention relate to a mixture in which the isocyanate component of the rigid polyurethane foam contains 25% by weight or less of tolylene diisocyanate in a polynuclear body of diphenylmethane diisocyanate, and the polyol component is tolylene diamine, glycerin. , Shoe close,
The heat insulating box is made of a mixed foam obtained by combining a mixture obtained by adding ethylene oxide and / or propylene oxide to at least one selected from bisphenol A and triethanolamine with a catalyst, a foam stabilizer, water, and cyclopentane. At least 500mm from urethane inlet
The thermal conductivity of the core layer heat insulating material having a thickness of about 20 to 25 mm away from the foam part and the heat insulating core having a thickness of about 20 to 25 mm from the foam part at least 50 mm away from the outer surface of the urethane-filled part. The thermal conductivity of the material is 17.5 to 18.5 mW / m · K at an average temperature of 10 ° C., and the dimensional change rate when the material is left to deteriorate for 24 hours at 70 ° C. and −20 ° C. in air is 2%. % And a flowable rigid polyurethane foam having a foam elongation of at least 2.6 mm / g per resin.

The fifth and sixth inventions relate to a mixture in which the isocyanate component of the rigid polyurethane foam contains 25% by weight or less of tolylene diisocyanate in a polynuclear body of diphenylmethane diisocyanate, and the polyol component is ethylene oxide and 40-50% by weight of a polyol having an OH value of 380-480 obtained by adding propylene oxide, and 10-20 of a polyol having an OH value of 300-400 obtained by adding ethylene oxide and propylene oxide to triethanolamine.
% By weight, 15 to 25% by weight of a polyol having an OH value of 450 to 500 obtained by adding propylene oxide to glycerin, 5 to 10% by weight of a polyol having an OH value of 400 to 450 obtained by adding propylene oxide to shoelace. A polyol having an average OH value of 350 to 450, containing 5 to 15% by weight of a polyol having an OH value of 200 to 300 and obtained by adding ethylene oxide to bisphenol A, is mixed with 100 parts by weight of a catalyst, a foam stabilizer and a polyol mixture. Of hard polyurethane foam in which 2.0 to 2.5 parts by weight of water and 10 to 14 parts by weight of cyclopentane are combined.

The average OH value of the mixed polyol composition is 35.
If it is less than 0, the compressive strength and dimensional stability decrease, and if it exceeds 450, the foam tends to become brittle, and the average OH value is preferably from 350 to 450, which is preferable for producing a rigid polyurethane foam. Here, the OH value refers to sample 1
The number of mg of potassium hydroxide (mg KOH / g) required to neutralize acetic acid bound to the acetylated product obtained from g.

The rigid polyurethane foam of the present invention is obtained by reacting cyclopentane with isocyanate in the presence of water, a foam stabilizer and a reaction catalyst using a polyol component as a basic raw material. Since it is not clear why the low density, high fluidity and high strength of the cyclopentane formulation are compatible, the relationship between the solubility, compressive strength, and dimensional stability of cyclopentane blowing agent in various polyols was investigated. As a result, it has been found that compounds having lower solubility in polyols and isocyanates have higher compressive strength and dimensional stability of urethane foam than those having higher solubility in cyclopentane as a blowing agent. The solubility of cyclopentane in the polyol varies depending on the alkylene oxide to be added, and the property of adding propylene oxide is higher than that of ethylene oxide. From the viewpoint of premix stability, a system having high solubility in cyclopentane is desirable, while a system having low solubility tends to be preferable from the viewpoint of improvement in cell skeleton strength.
That is, it has been found that compatibility between the compatibility with the cyclopentane blowing agent and the foam strength is an important factor in selecting a polyol and isocyanate mixture composition.

The rigid polyurethane foam of the present invention uses a polyol system having a low solubility in cyclopentane, and conversely uses a polyol system having a low solubility to enhance the resin skeleton strength of the cell and to improve the premix stability. A suitable foam stabilizer was selected to obtain a balance. that time,
When the mixed polyol has a low solubility of less than 60 parts by weight of the polyol and the isocyanate, the compressive strength and the dimensional stability tend to decrease. The reason is that rigid polyols and isocyanates with low solubility have stronger urethane resin walls than cyclopentane, and the foaming agent is sufficiently sealed in the bubbles to reduce solvent plasticization to cyclopentane. it is conceivable that. Here, the polyol component having low cyclopentane solubility is referred to as a polyol component having low cyclopentane solubility when the polyol mixture system becomes opaque when 10% by weight of cyclopentane is mixed in the polyol.

[0013] It has also been found that a heat insulating material which reduces the thermal conductivity of the foam and reduces the difference in the surface condition between the skin layer and the core layer of the foam is excellent for reducing the amount of heat leakage from the refrigerator and the freezer. . The reason is that the low-density, high-flow urethane material is less likely to become resinous (double skin) in the skin layer as well as the core layer, and the shape inside the refrigerator cabinet wall is complicatedly bent. Therefore, it is considered that the urethane material having a low density and a high fluidity has a small difference in density between the skin layer and the core layer and a small difference in the cell diameter distribution of the foam.

In order to achieve a low-density, high-flowability and high-strength urethane material, which is the object of the present invention, the amounts of cyclopentane as a blowing agent and water in an auxiliary blowing agent are also greatly affected.
From the findings so far, it is known that the foam density can be easily reduced by using a large amount of both cyclopentane and water. Conventional foaming agents have a relatively high skeletal strength within the cell, so use a large amount of blowing agent such as chlorofluorocarbon and alternative chlorofluorocarbons, and use a small amount of water to adversely affect the thermal conductivity. , High fluidity and high strength characteristics were relatively easily compatible. However, in the case of cyclopentane formulations that are friendly to the global environment, unlike conventional foaming agents, the lower the foam density, the lower the saturated vapor pressure, the lower the skeletal strength in the cell and the lower the foam shrinkage, compressive strength and dimensional stability. There is. Therefore, as a means of increasing the saturated vapor pressure of the cyclopentane formulation, the amount of cyclopentane foaming agent is reduced, contrary to the conventional foaming agent, and the amount of water that adversely affects the thermal conductivity is increased. A study was made to increase the pressure inside the bubble cell by increasing the partial pressure of carbon dioxide and to achieve both low density and high strength. At that time, the amount of water to be mixed with cyclopentane is
If the solubility is close to the limit value, it may cause layer separation at the time of premixing, or may be a factor of deteriorating the thermal conductivity.
However, it has been found that the cyclopentane formulation has less effect of water on the thermal conductivity than the conventional blowing agent. The optimum mixing ratio of water and cyclopentane is preferably 7 parts by weight or less of cyclopentane per 1 part by weight of water. That is, it is more preferable to use 2.0 to 2.5 parts by weight of water and 10 to 14 parts by weight of cyclopentane with respect to 100 parts by weight of the polyol component. If the amount of water is less than 100 parts by weight of the polyol component, the compressive strength and dimensional stability are poor,
When the amount of water is higher, the thermal conductivity tends to be significantly deteriorated. If the amount of the cyclopentane blowing agent is too large, the compressive strength and dimensional stability will be poor.

Other polyols used in the present invention include polyester polyols. For example, a polyol of a polyhydric alcohol and polyhydric carboxylic acid condensation type and a cyclic ester ring-opening polymerization type polyol can also be used. Polyhydric alcohols are ethylene glycol, glycerin, trimethylolpropane, sugars are sucrose, sorbitol, alkanolamines are diethanolamine,
Triethanolamine, polyamines such as ethylenediamine and tolylenediamine, phenols such as bisphenol A, polycarboxylic acids such as adipic acid,
Phthalic acid, polycarboxylic acid and the like can be used. The amount of the polyester polyol is preferably a mixed system of 5 to 20 parts by weight.

As the reaction catalyst, for example, tertiary amines such as tetramethylhexamethylenediamine, trimethylaminoethylpiperazine, pentamethyldiethylenetriamine, and triethylenediamine, and formic acid of trimethylaminoethylpiperazine, and slow-acting properties such as combined use of dipropylene glycol. All conventionally known catalysts can be used as long as the reactivity, such as a catalyst, matches. The amount of the reaction catalyst is preferably 3 to 5 parts by weight per 100 parts by weight of the polyol component.

Further, as a foam stabilizer, for example, X-20-1548 and X-20-1614, manufactured by Shin-Etsu Chemical Co., Ltd.
From the viewpoint of the stability of premix compatibility such as X-20-1634, those having a Si molecular weight of 1800 to 3000 and a Si content of 25 to 30 suitable for relatively low emulsifying action are more preferable. That is, it is possible to use an alkylene oxide-modified polydimethylsiloxane having an OH group or an alkoxy group at its terminal, such as an organic silicone compound or a fluorine compound. The amount of the foam stabilizer is 100
1-4 parts by weight per part by weight is preferred.

The mixed composition for a rigid polyurethane foam may include a filler, a flame retardant,
Additives such as reinforcing fibers and colorants can also be included.

As the isocyanate, any known isocyanate can be used, but most generally, tolylene diisocyanate (TDI) and diphenylmethane diisocyanate (MDI). TDI is a mixture of isomers, that is, 2,4-isomer 100%, 2,4-isomer / 2,6-isomer = 80/20, 65/35 (weight ratio) as well as trade name Mitsui Cosmonate Co., Ltd. TRC TD containing polyfunctional tar such as Takeda 4040 from Takeda Pharmaceutical Co., Ltd.
I can also be used. As MDI, in addition to pure products containing 4,4'-diphenylmethane diisocyanate as a main component, Mitsui Cosmonate Co., Ltd. M-200, which contains polyhedra of three or more nuclei, Takeda Pharmaceutical Co., Ltd. ) Can be used. In addition, prepolymerized isocyanates such as aromatic or aliphatic polyfunctional isocyanates such as 1,6-hexamethylene diisocyanate, toluidine isocyanate, and xylylene diisocyanate, urethane-modified tolylene diisocyanate, and carbodiimide-modified diphenylmethane diisocyanate are also used. can do. In particular, among the above, 80 parts of polymethylene polyphenyl diisocyanate (NCO% = 31) and 25 parts of a mixed system of 2,4-form, 2,6-form of modified tolylene diisocyanate, and polyfunctional prepolymerization The following are optimal. If the modified tolylene diisocyanate is used in an amount of 25 parts or more, a problem occurs in that the adhesiveness is significantly reduced.

The foam of the rigid polyurethane foam of the present invention is formed by a usual foaming machine used in the art.
For example, PU-30 foaming machine manufactured by Promart is used. The foaming conditions vary somewhat depending on the type of foaming machine, but usually the liquid temperature is 18 to 30 ° C and the discharge pressure is 80 to 150 kg / c.
m ² , discharge rate 15-30kg / min, mold box temperature 35 ~
45 ° C is preferred. More preferably, the liquid temperature is 20 ° C., the discharge pressure is 100 kg / cm ² , the discharge rate is 25 kg / min, and the temperature of the mold box is around 45 ° C.

The rigid polyurethane foam to be foam-filled in the refrigerator and the freezer thus obtained is filled with a urethane material which has both low density, high fluidity and high strength, thereby reducing the foam filling amount. Thus, cost reduction and weight reduction can be achieved. Further, since the foam has excellent compressive strength and dimensional stability and high fluidity, the amount of heat leakage is reduced and energy saving is achieved.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the present invention will be described in more detail in comparison with comparative examples. In addition, in description of an Example, a part and% show a weight part.

(Examples 1 to 6) (Comparative Examples 1 to 3) Average hydroxyl (OH) value is 380 to 48
Tolylenediamine-based polyether polyol (hereinafter referred to as polyol A) added with propylene oxide and ethylene oxide having an average hydroxyl value of 300 to 400
Triethanolamine-based polyether polyol (hereinafter referred to as polyol B) added with propylene oxide and ethylene oxide, having an average hydroxyl value of 450 to 50
Glycerin-based polyether polyol (hereinafter, referred to as polyol C) added with propylene oxide of 0, a shoe-closed-based polyether polyol (hereinafter, referred to as polyol D) added with propylene oxide having an average hydroxyl value of 400 to 450, and an average hydroxyl value of Is a bisphenol A-based polyether polyol (hereinafter referred to as polyol E) added with ethylene oxide of 200 to 300, and a trimethylolpropane-based polyether polyol (hereinafter referred to as polyol F) added with propylene oxide having an average hydroxyl value of 400 to 750. Having an average hydroxyl value of 250 to 45
A mixed polyol component of tolylenediamine-based polyester polyol (hereinafter referred to as polyol G) added with ethylene oxide of 0 (average hydroxyl value is 350 to 450) 1
Using 2.0 parts of water, 2.0 parts of water and 13 parts of cyclopentane (manufactured by Zeon Corporation) as a foaming agent, and trimethylaminoethylpiperazine (manufactured by Kao Corporation) as a reaction catalyst.
1.6 parts, 2.4 parts of trimethylaminoethylpiperazine (manufactured by Tosoh Corporation), 0.4 part of a dipropylene glycol solution of triethylenediamine (manufactured by Tosoh Corporation), and an organic silicone compound (X- 20-1548, manufactured by Shin-Etsu Chemical Co., Ltd., 2 parts, polymethylene polyphenyl diisocyanate (NCO% = 3) as an isocyanate component
1) 80 parts and the modified tolylene diisocyanate system
A rigid polyurethane foam was prepared by filling and foaming a mixed system of 2,4-form, 2,6-form, and polyfunctional prepolymer using 20 parts. First, Table 1 shows the results of physical properties and characteristics of the heat insulating material filled with the hard polyurethane foam of the heat insulating door shown in FIG. In addition, each physical property and characteristic of Table 1 were measured as follows.

[0024]

[Table 1]

Skin Density: The weight (A) of a 50 mm × 50 mm × 35 tmm skin-equipped foam is measured from a urethane-filled insulating material portion at least 500 mm away from the urethane inlet. After adjusting the zero point of distilled water and the foam attached to the metal needle in the beaker with a balance, the volume (B) when the foam is submerged with the metal needle is measured, and the weight (A) is converted into the volume (B). The divided value was evaluated.

Core layer density: A 200 mm × 200 mm × 20 to 25 (t) mm foam is measured from a urethane-filled insulating material portion at least 500 mm away from the urethane inlet, and the weight is divided by the volume. The values are shown below.

Low temperature dimensional change: When a foam of 150 mm × 300 mm × 20 to 25 (t) mm is left at −20 ° C. for 24 hours from a urethane-filled heat insulating material portion at least 500 mm away from the urethane inlet. It was indicated by the thickness dimensional change rate.

High-temperature dimensional change rate: A thickness of a 150 mm × 300 mm × 20 to 25 (t) mm foam left at 70 ° C. for 24 hours from a urethane-filled insulating material portion at least 500 mm away from the urethane inlet. Dimensional change rate.

Thermal conductivity: A foam of 200 mm × 200 mm × 20 to 25 (t) mm is formed from a part of a urethane-filled heat insulating material at least 500 mm away from a urethane injection port by using a model HC-073 manufactured by Eiko Seiki (heat flow meter). Method, average temperature 1
0 ° C).

Compressive strength: A foam of 50 mm × 50 mm × 20 to 25 (t) mm is loaded at a feed rate of 4 mm / min from a urethane-filled heat insulating part at least 500 mm away from the urethane inlet, and is deformed by 10%. The load at the time was indicated by a value obtained by dividing the load by the original pressure receiving area. Flexural strength: 80 mm × 2 from urethane-filled heat insulating material at least 500 mm away from urethane inlet
50mm × 20 ～ 25 (t) mm form feed rate 10mm
/ Min, and the load at the time of foam breakage was divided by the square of the width and thickness of the foam.

Foam elongation: 550 mm × 580 mm × 3
It is shown by foam elongation per urethane filling when foamed in a 5 (t) mm inverted L panel.

The examples and comparative examples of the present invention will be described below based on the contents of hard polyurethane foam filling the space inside the cabinet wall of the outer box and the inner box of the refrigerator and the freezer, and the space inside the outer door faceplate and the inner door wall. explain. FIG. 1 is a schematic diagram of a heat-insulating box and a heat-insulating door, and FIG. First, assemble an iron outer box and a plastic inner box, and an iron outer door and a plastic inner door to produce a box and door before urethane foam foaming to be filled in a refrigerator, and then set it on a urethane foam foaming employment. By performing preheating, the rigid polyurethane foam is placed in the void portion (polyol mixture and water, cyclopentane,
The mixture is pre-mixed with a catalyst and a foam stabilizer and isocyanate). At that time, the polyol and the isocyanate of the urethane foam chemically react and are pressurized by the foaming pressure, and the foamed urethane foam is injected into a refrigerator cabinet and a door to form an insulating box.

After setting the urethane materials of Examples 1 to 6 and Comparative Examples 1 to 3 in a zero pack (referred to as a minimum injection amount required for filling in the actual machine), a box refrigerator in which the pack ratio was 110% was filled. At least 500 from urethane inlet
From the urethane-filled insulating material part at least 50 mm away from the door outer surface, a foam sample was collected from the urethane-filled insulating material part separated by at least 50 mm and injected at a pack ratio of 115 to 120%. And foam samples were taken and various physical properties and characteristics were evaluated. At that time, the temperature at the time of injection was about 45 ° C, and the temperature of the polyol liquid and the isocyanate liquid was about 20 ° C.
Table 1 shows the results. Table 1 shows that the heat insulating materials of Examples of the present invention have lower skin layer density and core layer density, lower low-temperature dimensional change rate, high-temperature dimensional change rate and bubble cell diameter distribution than the heat insulating materials of Comparative Examples, It was found that the conductivity was reduced, the compressive strength and the flexural strength were increased, and the foam elongation was improved.

Further, using a refrigerator insulation box having an inner volume of about 150 to 180 L in the interior space of the cabinet wall, the packing ratio was 110% for Examples 1 and 2 and Comparative Examples 1 and 2.
The actual filling amount of urethane at that time was evaluated. As a result, in a refrigerator box having an internal volume of about 180 L, which differs depending on the model, Comparative Examples 1 and 2 require a filling amount of 6.35 to 6.60 kg, whereas Examples 1 and 2 require a filling amount of 6.35 to 6.60 kg. For urethane materials, a filling amount of 5.45 to 5.90 kg is sufficient. Further, in a refrigerator box having an inner volume of about 150 L, the urethane material of Comparative Examples 1 and 2 was 5.35 to 5.65 kg, while that of Example 1,
In No. 2, it was confirmed that the filling amount could be reduced to 4.65 to 5.00 kg, and about 10 to 18% of the urethane material could be saved. On the other hand, the actual filling amount of urethane when the pack ratio was 115 to 120% was evaluated for Examples 1 and 2 and Comparative Examples 1 and 2 using a refrigerator door having an inner volume of about 12 to 20 L in the inner space of the door wall. As a result, in the refrigerator door having an internal volume of about 20 L, which differs depending on the model, the filling amount of 0.90 to 1.05 kg is required for Comparative Examples 1 and 2, whereas the urethane of Examples 1 and 2 is required. 0.76 to 0.8 for material
A filling amount of 2 kg is sufficient. In a refrigerator door having an inner volume of about 12 L, the urethane material of Comparative Examples 1 and 2 was 0.59.
0.47 to 0.52 kg in Examples 1 and 2,
, And it was confirmed that about 10 to 18% of the urethane material could be saved. In addition, the refrigerating cycle parts (compressor / condenser / evaporator) were re-arranged in the refrigerator box on which the heat insulating material was formed, the door was mounted, and the amount of heat leakage was measured. Reduces heat leakage by 3-6% and reduces power consumption by about 1-2KWh
/ Monthly energy saving. From the above, the rigid polyurethane foam of the present invention has low density, high fluidity and high strength characteristics, so that the cost reduction and weight reduction due to the effect of reducing the urethane foam filling amount, the compressive strength and dimensional stability of the foam are achieved. And energy savings were also achieved due to the effect of reducing the amount of heat leakage.

Table 1 shows the physical properties and characteristics of the rigid urethane foam (skin layer density, core layer density, dimensional change rate, cell diameter distribution, thermal conductivity, compressive strength, bending strength, foam elongation).
Is shown.

[0036]

According to the present invention, in a heat-insulating box and a heat-insulating door in which a low-density, high-flow and high-strength rigid polyurethane foam is foam-filled, cost reduction and weight reduction can be achieved by reducing urethane filling amount. In addition, the present invention provides a high-quality refrigerator and freezer product that has excellent compressive strength and dimensional stability, and can save energy by reducing the amount of heat leakage.

[Brief description of the drawings]

FIG. 1 is a schematic view of filling a rigid polyurethane foam with a heat insulating box.

FIG. 2 is a schematic diagram of filling a rigid polyurethane foam with a heat insulating door.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Insulated box, 2 ... Urethane injection head, 3 ... Urethane flow, 4 ... Urethane injection port, 5 ... Sample collection position,
6 ... measurement sample, 7 ... insulated door.

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Katsumi Fukuda, inventor, 800 Tomita, Ohira-cho, Ohira-cho, Shimotsuga-gun, Tochigi Pref.

Claims (6)

[Claims] 1. A refrigerator in which a space inside a cabinet wall of an outer box and an inner box and a space inside an outer door surface iron plate and an inner door wall are filled with a hard polyurethane foam using a mixed foaming agent of cyclopentane and water. Insulated boxes and insulated doors
At least 500 mm from the urethane inlet
The foam and the heat insulating door which are separated by at least 50 mm from the outer surface of the urethane-filled portion have an overall skin layer density of 34.5 to 37.5 kg / m ³ and a core layer density of 3
2.5 to 34.5 kg / m ³ and compressive strength of 0.15 to 0.2MP
(a) A heat insulating box and a heat insulating door for a refrigerator, comprising a heat insulating material of a rigid polyurethane foam having a bending strength of 0.4 to 0.5 MPa. 2. A freezer in which a space inside a cabinet wall of an outer box and an inner box of a freezer, and a space inside an outer door surface iron plate and an inner door wall are filled with a hard polyurethane foam using a mixed foaming agent of cyclopentane and water. Insulated boxes and insulated doors
At least 500 mm from the urethane inlet
The foam and the heat insulating door which are separated by at least 50 mm from the outer surface of the urethane-filled portion have an overall skin layer density of 34.5 to 37.5 kg / m ³ and a core layer density of 3
2.5 to 34.5 kg / m ³ and compressive strength of 0.15 to 0.2MP
a, a heat insulating box and a heat insulating door of a freezer, which are made of a heat insulating material of a rigid polyurethane foam having a bending strength of 0.4 to 0.5 MPa. 3. A rigid polyurethane foam wherein the isocyanate component is a mixture of polyphenylene diphenylmethane diisocyanate and 25% by weight or less of tolylene diisocyanate, and the polyol component is tolylene diamine,
It is composed of a mixed foam obtained by combining at least one selected from glycerin, pseudo rose, bisphenol A and triethanolamine with ethylene oxide and / or propylene oxide in combination with a catalyst, a foam stabilizer, water and cyclopentane. The heat conductivity of the core layer heat insulating material having a thickness of about 20 to 25 mm from the foam portion where the heat insulating box is at least 500 mm away from the urethane inlet and the heat insulating door is at least 5 mm from the outer surface of the urethane filled portion.
Approximately 20 to 25 mm thick from the foam part separated by 0 mm or more
The thermal conductivity of the core layer heat insulating material is 17.5 at an average temperature of 10 ° C.
１８18.5 mW / m · K, dimensional change rate of 2% or less when left to deteriorate for 24 hours at 70 ° C. and -20 ° C. in air, and foam elongation per resin of 2.6 mm
A heat insulating box and a heat insulating door for a refrigerator, comprising a heat insulating material of a rigid polyurethane foam having a fluidity of at least / g. 4. A mixture in which the isocyanate component of the rigid polyurethane foam contains 25% by weight or less of a tolylene diisocyanate in a polynuclear diphenylmethane diisocyanate, and the polyol component is tolylene diamine.
It is composed of a mixed foam obtained by combining at least one selected from glycerin, pseudo rose, bisphenol A and triethanolamine with ethylene oxide and / or propylene oxide in combination with a catalyst, a foam stabilizer, water and cyclopentane. The heat conductivity of the core layer heat insulating material having a thickness of about 20 to 25 mm from the foam portion where the heat insulating box is at least 500 mm away from the urethane inlet and the heat insulating door is at least 5 mm from the outer surface of the urethane filled portion.
Approximately 20 to 25 mm thick from the foam part separated by 0 mm or more
The thermal conductivity of the core layer heat insulating material is 17.5 at an average temperature of 10 ° C.
１８18.5 mW / m · K, dimensional change rate of 2% or less when left to deteriorate for 24 hours at 70 ° C. and -20 ° C. in air, and foam elongation per resin of 2.6 mm
A heat insulating box and a heat insulating door of a freezer, comprising a heat insulating material of a rigid polyurethane foam having a fluidity of at least / g. 5. A rigid polyurethane foam obtained by adding a diphenylmethane diisocyanate-based polynuclear compound containing 25% by weight or less of a tolylene diisocyanate-based isocyanate component and a polyol component obtained by adding ethylene oxide and propylene oxide to tolylenediamine. 40 to 50% by weight of a polyol having an OH value of 380 to 480, and an OH value of 300 to 50% obtained by adding ethylene oxide and propylene oxide to triethanolamine.
OH value of 450 to 5 obtained by adding propylene oxide to glycerin.
15 to 25% by weight of a polyol having an OH value of 400 to
450 to 5% by weight of polyol, bisphenol A
Value obtained by adding ethylene oxide to
A polyol having an average OH value of 350 to 450 containing 5 to 15% by weight of a polyol having a viscosity of 300, a catalyst, a foam stabilizer,
A heat-insulating box for a refrigerator, comprising a hard polyurethane foam heat-insulating material in which 2.0 to 2.5 parts by weight of water and 10 to 14 parts by weight of cyclopentane are combined with respect to 100 parts by weight of a polyol mixture. And insulated doors. 6. A rigid polyurethane foam wherein the isocyanate component is a mixture of polyphenylene diphenylmethane diisocyanate containing 25% by weight or less of tolylene diisocyanate, and the polyol component is obtained by adding ethylene oxide and propylene oxide to tolylene diamine. 40 to 50% by weight of a polyol having an OH value of 380 to 480, and an OH value of 300 to 50% obtained by adding ethylene oxide and propylene oxide to triethanolamine.
OH value of 450 to 5 obtained by adding propylene oxide to glycerin.
15 to 25% by weight of a polyol having an OH value of 400 to
450 to 5% by weight of polyol, bisphenol A
Value obtained by adding ethylene oxide to
A polyol having an average OH value of 350 to 450 containing 5 to 15% by weight of a polyol having a viscosity of 300, a catalyst, a foam stabilizer,
A heat insulating box for a freezer, comprising a hard polyurethane foam heat insulating material in which 2.0 to 2.5 parts by weight of water and 10 to 14 parts by weight of cyclopentane are combined with 100 parts by weight of a polyol mixture. And insulated doors.