JP2014206336A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To direct to a refrigerator in which an occupied area rate of a vacuum heat insulation material installed in a heat insulation box is set to be equal to or higher than 60%, and provide a refrigerator that can reduce heat conductivity of a thinner portion in which the vacuum heat insulation material is installed to improve the heat leakage quantity of the box, and that can preferably also improve the mechanical strength of the thinner portion.SOLUTION: The invention directs to a refrigerator in which an occupied area ratio of a vacuum heat insulation material is equal to or higher than 60%. Polyol premix that is a mixture of polyol comprising three or more components that are a mixture of at least 60% or more of sucrose-based polyol, 30% or less of toluene di-amine-based polyol, and 10% or more of polyester polyol, foam stabilizer, reaction catalyst, water, and cyclopentane, as well as each of or a combination of two or more of pentamethyldiethylenetriamine, triethylenediamine, N,N,N'-trimethylaminoethylethanolamine, and N,N, N',N'-tetramethylethylenediamine is filled, together with isocyanate, in a filled space of a heat insulation box of a refrigerator and foamed.

Description

  The present invention relates to a refrigerator that refrigerates or freezes food and beverages, and more particularly to a refrigerator in which a heat insulating box is filled with polyurethane foam.

As a social effort to prevent global warming, energy conservation is being promoted in various fields in order to control carbon dioxide (CO ₂ ) emissions. For example, even in recent refrigerators that are electrical products, particularly refrigerator-related home appliances, refrigerators with improved heat insulation performance have become mainstream from the viewpoint of reducing power consumption. For that purpose, a structure in which the cool air inside the refrigerator does not escape to the outside of the refrigerator is indispensable.

  A refrigerator is comprised by the heat insulation box which is a refrigerator main body, and the door which opens and closes the front opening part of the storage chamber provided in the heat insulation box. In order to prevent the cold air inside the refrigerator from escaping to the outside of the refrigerator, it is effective to improve the heat insulation performance of the heat insulation box and the heat insulation door. For this reason, polyurethane foam is filled in the heat insulation box and the heat insulation door, and a vacuum heat insulating material is disposed inside the polyurethane foam to suppress heat transfer.

  Generally, a heat insulating box of a refrigerator is composed of an outer box made of iron plate and an inner box made of synthetic resin, and a heat insulating material using polyurethane foam having air bubbles in the space between the outer box and the inner box. Filled. This polyurethane foam is obtained by reacting a polyol component and an isocyanate component in the presence of a foaming agent, a reaction catalyst, and a foam stabilizer. CFC-11, which has been widely used as a foaming agent for polyurethane foam, was completely abolished in Japan and the United States at the end of 1995, and HCFC-141c was abolished by the end of 2003. As a result, non-fluorocarbon foaming agents that are less likely to destroy the ozone layer have become active substitutes for hydrocarbon compounds, especially in Europe. In Japan, foaming agents such as cyclopentane are used in polyurethane foams as heat insulation materials for refrigerators. Have been used.

  However, cyclopentane has a problem that heat conductivity is high and heat insulation performance is greatly inferior to that of fluorocarbon foaming agents. Moreover, since the polyurethane foam of the cyclopentane formulation has a high density and poor fluidity, unless a large amount of polyurethane is used, the polyurethane is not filled in detail, and there is a problem that heat insulation performance and strength cannot be ensured sufficiently. . In response to this problem, a cyclopentane formulation has been developed which can increase the amount of water used in combination with cyclopentane as a foaming agent to achieve both low density and high strength properties.

  As an example of such a polyurethane foam using cyclopentane, Japanese Patent Application Laid-Open No. 2004-27074 (Patent Document 1) describes a polyurethane foam having reduced thermal conductivity (improved thermal insulation performance) and improved dimensional stability. A composition is disclosed.

JP 2004-27074 A

  By the way, in recent years, a refrigerator having further improved heat insulation performance has been demanded, and in order to meet this demand, a design for increasing the thickness of the vacuum heat insulating material has been studied. However, when the vacuum heat insulating material is thickened, the space in which the polyurethane foam raw material flows inside the heat insulating box narrows, and a phenomenon that makes it difficult to sufficiently fill the polyurethane foam has occurred. Similarly, due to demands for space saving in refrigerators, the space inside the heat insulation box narrows and the complicated shape occurs, and the space in which the urethane foam raw material flows inside the heat insulation box becomes narrow, making polyurethane foam sufficient The phenomenon became difficult to fill.

  As described above, in recent heat insulation boxes of refrigerators, there are many examples in which at least a plurality of thick vacuum heat insulating materials are used to improve heat insulation performance. However, by arranging the vacuum heat insulating material, the gap between the heat insulating box and the wall surface of the heat insulating box is narrowed, and the flow of the polyurethane foam raw material is inhibited. For this reason, (1) variations in polyurethane properties such as thermal conductivity and mechanical strength occur, (2) voids due to unfilled polyurethane foam raw materials, and (3) density variation is suppressed by increasing the filling pressure of polyurethane. Then, the subject that the filling amount of a polyurethane foam raw material increases newly generate | occur | produces. In order to solve such a problem, it is necessary to improve the fluidity of the polyurethane foam raw material itself in order to smoothly flow and fill the polyurethane foam raw material into the narrowed flow space.

  Here, in particular, energy saving is strongly demanded, and in a refrigerator, it is important to improve the area occupied by the vacuum heat insulating material. Therefore, in order to improve the heat insulation performance, (1) increase the thickness of the vacuum heat insulating material, (2) increase the occupied area of the vacuum heat insulating material, the shape of the vacuum heat insulating material along the shape of the heat insulating box. It is thought that it is possible to cope with such methods as polygonalization, (3) the shape of the vacuum heat insulating material straddling the hot gas pipe, (4) the shape of the vacuum heat insulating material is three-dimensionally shaped along the shape of the heat insulating box. It is done.

  However, the gap between the wall surface of the heat insulation box is narrowed in any of the measures, which causes an obstacle to the flow of the polyurethane raw material, due to generation of unfilled voids and non-uniformity of the polyurethane foam properties. There was a problem in that the thermal insulation performance was uneven. In particular, since the space that has become narrow due to the installation of vacuum insulation is thinned, the thermal conductivity of polyurethane foam is usually due to the growth of skin layers (layers where polyurethane foam becomes dense due to insufficient foaming). The thickness tends to be significantly worse than the part where the thickness is secured. In general, the skin layer of polyurethane foam is considered to be formed by shear stress due to the difference in flow rate of polyurethane foam based on the difference in urethanization reaction between the central part and the wall surface in the thickness direction of polyurethane foam. ing. That is, the central portion generates reaction heat of 100 ° C. or more due to the urethanization reaction, and the catalytic activity is also activated to promote foaming, whereas the temperature of the urethanization reaction becomes closer to the wall surface side away from the central portion. The catalyst activity becomes inactive and the foaming tends to be weakened. In particular, since the internal heat generation of the polyurethane foam is reduced in the thinned portion, the catalytic function cannot be sufficiently exhibited, and there is a problem of adversely affecting the formation of the skin layer and the thermal conductivity. And if heat conductivity becomes high, the amount of heat leakage from which heat escapes from the heat insulation box will increase, and as a result, energy saving will be hindered.

  In addition to these problems, the following problems were newly found. Flow analysis simulation was conducted on the reactivity of the urethanization reaction that favors the filling property of the polyurethane foam material in the heat insulation box of the refrigerator where the area occupied by the vacuum insulation material increased and the flow space of the polyurethane foam material became narrow . As a result, it was found that when the reactivity is slow, the polyurethane foam raw material flows through the filling space in a liquid state, so that unevenness hardly occurs when the foam rises, and the polyurethane foam raw material can be filled to every corner without difficulty. For this reason, it turned out that a polyurethane foam raw material can be poured in the narrow space as mentioned above. However, when the reactivity of the urethanization reaction is slowed down in this way, the cells (bubbles) formed in the polyurethane foam grow by increasing the time until the reaction is completed, so the polyurethane foam has a large cell diameter. There is a possibility that new problems such as a decrease in heat insulation characteristics and a deterioration in strength may occur.

  By the way, in an actual refrigerator for energy saving, in order to obtain effective heat insulation performance, the occupation area ratio of the vacuum heat insulating material installed in the heat insulation box (with respect to the entire area filled with polyurethane of the heat insulation box) There is a strong demand for the ratio of the vacuum insulation to 60% or more. However, if a vacuum heat insulating material having such a large occupied area is arranged in the heat insulating box body, a large number of thin portions are formed between the heat insulating box body and the vacuum heat insulating material, so that a stable polyurethane foam may not be formed. was there. Therefore, in refrigerators that occupy 60% or more of the vacuum heat insulating material installed in the heat insulation box, heat insulation performance and mechanical properties are ensured by ensuring the fluidity of the polyurethane foam raw material and uniform foaming with few skin layers. The search and development of polyurethane raw materials that can improve strength is strongly desired.

  The object of the present invention is to reduce the thermal conductivity in the thin wall portion where the vacuum heat insulating material is installed, targeting a refrigerator in which the occupation ratio of the vacuum heat insulating material installed in the heat insulating box is 60% or more. It is another object of the present invention to provide a refrigerator that improves the amount of heat leakage of the box body, and preferably improves the mechanical strength of the thin wall portion.

  A feature of the present invention is a refrigerator having an occupation area ratio of 60% or more of a vacuum heat insulating material installed in a heat insulating space formed between an outer box and an inner box of a heat insulating box, and at least a shoe-closed polyol 60% or more, toluenediamine-based polyol 30% or less, polyester polyol blended at least 10% three-component polyol, and premix polyol blended with foam stabilizer, water and cyclopentane In addition, a premix containing pentamethyldiethylenetriamine, triethylenediamine, N, N, N'-trimethylaminoethylethanolamine, N, N, N ', N'-tetramethylethylenediamine as a catalyst or a combination of two or more of them as a catalyst Fill the filling space of the refrigerator heat insulation box together with the isocyanate. To was foamed, it is in place.

  Furthermore, the polyurethane foam may be formed by using the same polyurethane raw material not only in the heat insulation box but also in the heat insulation door.

  According to the present invention, the foamed state of the polyurethane foam in each part of the heat insulation box is stabilized by improving the fluidity of the polyurethane foam raw material and suppressing the generation of the skin layer having inferior heat insulation performance. It is possible to improve the heat insulation performance by reducing the overall thermal conductivity. In addition, since the fluidity is improved, a stable foamed state can be secured even in a thin portion with a small amount of polyurethane foam raw material, thereby improving the mechanical strength.

It is explanatory drawing explaining the filling method which fills the polyurethane foam in the heat insulation box of a refrigerator. It is explanatory drawing explaining the composition and various characteristics of the polyurethane foam raw material of this invention, and the conventional polyurethane foam raw material.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiments, and various modifications and application examples are included in the technical concept of the present invention. Is also included in the range.

  First, the filling method of the polyurethane foam of the refrigerator in which a vacuum heat insulating material is used is demonstrated. In this figure, unnecessary devices are omitted for simplification. In FIG. 1, the heat insulating box 3 of the refrigerator is composed of an outer box 4 and an inner box 5 built in the outer box 4. Further, a vacuum heat insulating material 6 is disposed between the outer box 4 and the inner box 5. In the heat insulating box 3, the polyurethane foam raw material is injected from the polyurethane injection head 1 at four locations from the upper side of the polyurethane inlet 2 provided in the heat insulating box 3 with the side to which the heat insulating door is attached facing down. The injected polyurethane foam raw material flows and moves in the space between the outer box 4 and the inner box 5, and then sequentially reacts and hardens.

  And the composition of the polyurethane foam raw material filled between the outer box 4 and the inner box 5 is as follows. Next, the composition of the polyurethane foam raw material according to the present invention will be described in detail.

  The premix polyol mixed with the isocyanate is a premix polyol composition comprising a polyol, a foam stabilizer, a reaction catalyst, water and a blowing agent containing cyclopentane. This premix polyol composition is composed of one or more polyhydric alcohols having 4 to 8 hydroxyl groups and a polyhydric compound having an ester group that is incompletely dissolved in the polyol and a compound obtained by adding an alkylene oxide to the mixture. It is a premix polyol of at least 3 components including 1 type or 2 types or more of alcohol.

  Examples of the polyhydric alcohol having 7 to 8 hydroxyl groups include sugars such as sucrose and lactose, derivatives thereof, and phenols. Examples of the polyhydric alcohol having 4 hydroxyl groups include diglycerin, pentaerythritol, methyl glucoside, ethylenediamine, toluenediamine, diphenylmethanediamine, and tetramethylolcyclohexane. These may be used alone or in combination of two or more. In this embodiment, preferably, sucrose is used as the polyhydric alcohol having 7 to 8 hydroxyl groups, and toluenediamine is used as the polyhydric alcohol having 4 hydroxyl groups.

  Furthermore, the polyhydric alcohol having an ester group has 2 to 3 functional groups, and includes a number of phthalic anhydrides, terephthalic acid, isophthalic acid, succinic acid, adipic acid, maleic acid, fumaric acid, sebacic acid, malic acid, and the like. A polyester polyol obtained by a condensation reaction between a polyvalent carboxylic acid and a polyhydric alcohol such as ethylene glycol, diethylene glycol, triethylene glycol, 1,4-butanediol, glycerin, or trimethylolpropane.

  In this embodiment, a premix polyol composed of at least a three-component system in which at least a shoe-closed polyol is 60% or more, a toluenediamine-based polyol is 30% or less, and a polyester polyol is 10% or more is used. Is.

  As the reaction catalyst, a foamed amine catalyst, a resinated amine catalyst, a trimerization catalyst or the like is generally used. In the present invention, the specific catalyst described below is blended with the premix polyol component having the above-described configuration. In this way, the fluidity and uniform foamability of the polyurethane foam raw material are ensured to improve the heat insulation performance and mechanical strength.

  As a specific reaction catalyst used in the present invention, pentamethyldiethylenetriamine is used as a foaming amine catalyst, and triethylenediamine, N, N, N′-trimethylaminoethylethanolamine, N, N, N ′, N′-tetramethylethylenediamine is used, and it is a great feature that each of them is blended alone or in combination. Further, it has been found by the inventors that the same action and effect cannot be achieved even when other catalysts than the above are used.

  Next, the polyisocyanate used in the present invention is not particularly limited as long as it is conventionally used. For example, there are diphenylmethane diisocyanate and derivatives thereof, which may be used alone or in combination with other polyisocyanates.

  Examples of diphenylmethane diisocyanate and its derivatives include a mixture of diphenylmethane diisocyanate and its polymer polyphenylpolymethylene diisocyanate, and a diphenylmethane diisocyanate derivative having a terminal isocyanate group.

  Other polyisocyanates include tolylene diisocyanate and its derivatives. Examples of the derivative include a mixture of 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate, a terminal isocyanate prepolymer derivative of tolylene diisocyanate, and the like.

  Examples of specific polyurethane foam raw materials using the specific reaction catalyst as described above in the above composition will be described.

  In this embodiment, three types of polyol components are used. As the first polyol component A, 60% of shoe-closed polyol is used, as the second polyol component B, 30% of toluenediamine-based polyol is used. Polyester polyol is 10% as the polyol component C, and these are mixed to make the polyol component 100%.

  And pentamethyldiethylenetriamine which is a foaming amine catalyst is used independently as a specific reaction catalyst. This pentamethyldiethylenetriamine is blended by 3%. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  And the refrigerator was produced by filling the polyurethane raw material which mixed these into the space | gap part of the outer box 4 and the inner box 5 of the heat insulation box which the occupation rate of a vacuum heat insulating material is 60% or more, and making it foam.

  The foaming process of the polyurethane foam raw material in the heat insulation box 3 of the refrigerator will be described. As shown in FIG. 1, the outer box 4 made of a steel plate and the inner box 5 made of a resin molded product are preliminarily adjusted to a predetermined temperature. Thereafter, the heat insulation box 3 is set on the foaming jig so that the front surface of the heat insulation box 3 is on the lower side and the back surface of the heat insulation box 3 is on the upper side. In this case, the foaming jig is also temperature-controlled in advance at a predetermined temperature. And a specified amount of polyurethane foam raw material (three kinds of polyol mixture, foaming agent composed of water and cyclopentane, pentamethyldiethylenetriamine as foaming amine catalyst, premixed polyol mixture composition and isocyanate premixed with foam stabilizer) Is injected into the gap. When injecting, a premix polyol mixture composition, which is a polyurethane foam raw material, and an isocyanate are collided and mixed in an injection head to promote a chemical reaction and pressurized by foaming pressure to form a polyurethane between the outer box 4 and the inner box 5. The foam is filled to complete the heat insulating box 3.

FIG. 2 shows the measurement results of physical properties and characteristics of the heat insulating material filled with polyurethane foam. The physical properties and characteristics shown in FIG. 2 were measured as follows.
(1) The thermal conductivity is a thick part A having a polyurethane foam thickness of 40 mm in this embodiment of the refrigerator in which the heat insulating box 3 filled with polyurethane raw material and foamed is formed. And the thermal conductivity in the thin-walled portion B where the thickness of the polyurethane foam is 15 mm (this portion is where the vacuum heat insulating material is present). For the measurement sample, a polyurethane foam having a predetermined width, length and thickness was cut out and evaluated by HC-073 type (heat flow meter method, average temperature 10 ° C.) manufactured by Eihiro Seiki.

Moreover, the deterioration rate of the thermal conductivity is a value obtained by calculating the difference between the thermal conductivity in the thin portion B and the thermal conductivity in the thick portion A and dividing the difference by the thermal conductivity in the thick portion A. And multiplied by 100%.
(2) The amount of heat leaked from the box is from the inside of the heat insulating box 3 by incorporating a refrigeration cycle component (compressor / condenser / evaporator) into the refrigerator in which the heat insulating box 3 filled with polyurethane foam and foamed is formed. The amount of heat leakage was measured. In FIG. 2, it represents with the ratio when the heat leak amount of a prior art example is set to 100.

And in Example 1, the thermal conductivity in the thick part A is 18.9 mW / m · K,
The thermal conductivity in the thin portion B was 19.2 mW / m · K. Moreover, the deterioration rate of the heat conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 1.6%. Furthermore, the heat leak rate ratio of the heat insulating box 3 was 93 points with respect to the case where the conventional example was 100 points, and an improvement effect of 7 points was obtained.

  Thus, in this example, shoe-closed polyol, toluene diamine, and polyester polyol are used, and pentamethyldiethylenetriamine is blended alone as a reaction catalyst, thereby making the amount of heat leakage smaller than before. It can be seen that there is an advantage.

  In this example, three types of polyol components are used. The first polyol component A is 63% sucrose-based polyol, the second polyol component B is 27% toluenediamine-based polyol, and the third Polyester polyol is 10% as the polyol component C, and these are mixed to make the polyol component 100%.

  And as a specific reaction catalyst, triethylenediamine which is a resinated amine catalyst is used alone. Only 3% of this triethylenediamine is blended. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

And in Example 2, the thermal conductivity in the thick part A is 19.2 mW / m · K,
The thermal conductivity in the thin portion B was 19.7 mW / m · K. Moreover, the deterioration rate of the heat conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 2.6%. Furthermore, the heat leak rate ratio of the heat insulation box 3 was 92 points compared to the case where the conventional example was 100 points, and an improvement effect of 8 points was obtained.

  Thus, in this example, shoe-closed polyol, toluene diamine, and polyester polyol are used, and triethylenediamine is blended alone as a reaction catalyst to this, so that the amount of heat leakage is smaller than conventional. It is greatly reduced and it can be seen that there is an advantage.

  In this example, three types of polyol components are used. The first polyol component A is 63% sucrose-based polyol, the second polyol component B is 27% toluenediamine-based polyol, and the third Polyester polyol is 10% as the polyol component C, and these are mixed to make the polyol component 100%.

  As a specific reaction catalyst, trimethylaminoethylethanolamine, which is a resinated amine catalyst, is used alone. This trimethylaminoethylethanolamine is blended by 3%. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

And in Example 3, the thermal conductivity in the thick part A is 19.5 mW / m · K,
The thermal conductivity in the thin portion B was 19.6 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 0.5%. Furthermore, the heat leak rate ratio of the heat insulation box 3 was 92 points compared to the case where the conventional example was 100 points, and an improvement effect of 8 points was obtained.

  Thus, in this example, shoe-closed polyol, toluene diamine, and polyester polyol are used, and trimethylaminoethylethanolamine is blended singly as a reaction catalyst. It can be seen that there is an advantage compared to

  In this example, three types of polyol components are used. As the first polyol component A, 60% of shoe-closed polyol is used, and as the second polyol component B, 25% of toluenediamine-based polyol is used. Polyester polyol is 15% as the polyol component C, and these are mixed to make the polyol component 100%.

  And as a specific reaction catalyst, tetramethylethylenediamine which is a resinated amine catalyst is used alone. This tetramethylethylenediamine is blended by 3%. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

And in Example 4, the thermal conductivity in the thick part A is 19.4 mW / m · K,
The thermal conductivity in the thin portion B was 19.7 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 1.5%. Furthermore, the heat leak rate ratio of the heat insulation box 3 was 92 points compared to the case where the conventional example was 100 points, and an improvement effect of 8 points was obtained.

  As described above, in this example, shoe-closed polyol, toluene diamine, and polyester polyol are used, and tetramethylethylene diamine is blended alone as a reaction catalyst. It can be seen that there is an advantage.

  In this example, three types of polyol components are used. The first polyol component A is 63% sucrose-based polyol, the second polyol component B is 27% toluenediamine-based polyol, and the third Polyester polyol is 10% as the polyol component C, and these are mixed to make the polyol component 100%.

  And as a specific reaction catalyst, pentamethyldiethylenetriamine which is a foaming amine catalyst, triethylenediamine which is a resinated amine catalyst, and tetramethylethylenediamine are used in combination. And, the blending ratio is 3% as a whole, 1% pentamethyldiethylenetriamine, 1% triethylenediamine and 1% tetramethylethylenediamine are blended. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

And in Example 5, the thermal conductivity in the thick part A is 19.4 mW / m · K,
The thermal conductivity in the thin portion B was 19.4 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 0% because the thermal conductivity did not change. Furthermore, the heat leak rate ratio of the heat insulation box 3 was 92 points compared to the case where the conventional example was 100 points, and an improvement effect of 8 points was obtained.

  Thus, in this example, shoe-closed polyol, toluenediamine, and polyester polyol are used, and pentamethyldiethylenetriamine, triethylenediamine, and tetramethylethylenediamine are blended in combination as a reaction catalyst. Thus, it can be seen that the amount of heat leakage is greatly reduced as compared with the prior art, and there is an advantage. In particular, in this example, it can be understood that a uniform foamed state is obtained because the heat conductivity of the thick portion A and the thin portion B is the same.

  In this example, three types of polyol components are used. The first polyol component A is 63% sucrose-based polyol, the second polyol component B is 27% toluenediamine-based polyol, and the third Polyester polyol is 10% as the polyol component C, and these are mixed to make the polyol component 100%.

  As a specific reaction catalyst, pentamethyldiethylenetriamine, which is a foaming amine catalyst, triethylenediamine, which is a resinated amine catalyst, and trimethylaminoethylethanolamine are used in combination. Moreover, pentamethyldiethylenetriamine is 1%, triethylenediamine is 1%, and trimethylaminoethylethanolamine is 1% so that the total content is 3%. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

And in Example 5, the thermal conductivity in the thick part A is 19.3 mW / m · K,
The thermal conductivity in the thin portion B was 19.3 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 0% because the thermal conductivity did not change. Furthermore, the heat leak rate ratio of the heat insulation box 3 was 92 points compared to the case where the conventional example was 100 points, and an improvement effect of 8 points was obtained.

  Thus, in this example, shoe-closed polyol, toluenediamine, and polyester polyol are used, and pentamethyldiethylenetriamine, triethylenediamine, and trimethylaminoethylethanolamine are combined in combination as a reaction catalyst. As a result, the amount of heat leakage is greatly reduced as compared with the prior art, and it can be seen that there is an advantage. In particular, it can be understood that a uniform foamed state is obtained also in the present embodiment because the thermal conductivity of the thick portion A and the thin portion B is the same as in the fifth embodiment.

In Example 5 and Example 6, pentamethyldiethylenetriamine, which is a foaming amine catalyst, and triethylenediamine, which is a resinated amine catalyst, are commonly used. Even if ethylenediamine and trimethylaminoethylethanolamine in Example 6 are not used, sufficient effects can be obtained.
≪Comparative example 1≫
In the comparative sample, two types of polyol components are used. The first polyol component A is 70% sucrose-based polyol, the second polyol component B is 30% toluene diamine-based polyol, and these are mixed. The polyol component is 100%.

  As a reaction catalyst for comparison, dimethylcyclohexylamine, which is a resinated amine catalyst, is used alone. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

  In Comparative Example 1, the thermal conductivity at the thick part A was 19.8 mW / m · K, and the thermal conductivity at the thin part B was 20.1 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 1.5%. Furthermore, the heat leak rate ratio of the heat insulating box 3 was 102 points with respect to the case where the conventional example was 100 points, and a deterioration of 2 points was recognized.

Thus, the shoe-closed polyol, toluenediamine-based polyol, and polyester polyol specified in the present invention, and pentamethyldiethylenetriamine, triethylenediamine, N, N, N′-trimethylaminoethylethanolamine, N, N, It can be understood that when the catalyst of N ′, N′-tetramethylethylenediamine is not blended alone or in combination, the amount of heat leakage increases and the heat insulation performance decreases.
«Comparative example 2»
In the comparative sample, two types of polyol components are used. The first polyol component A is 70% sucrose-based polyol, the second polyol component B is 30% toluene diamine-based polyol, and these are mixed. The polyol component is 100%.

  As a reaction catalyst for comparison, N, N ′, N ″ -tris (3-dimethylaminopropyl) hexahydro-s-triazine, which is a trimerization catalyst, is used alone. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

  In Comparative Example 2, the thermal conductivity at the thick portion A was 19.5 mW / m · K, and the thermal conductivity at the thin portion B was 20.2 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 3.6%. Furthermore, the heat leak rate ratio of the heat insulating box 3 was 101 points with respect to the case where the conventional example was 100 points, and a deterioration of 1 point was recognized.

Thus, the shoe-closed polyol, toluenediamine-based polyol, and polyester polyol specified in the present invention, and pentamethyldiethylenetriamine, triethylenediamine, N, N, N′-trimethylaminoethylethanolamine, N, N, It can be understood that when the catalyst of N ′, N′-tetramethylethylenediamine is not blended alone or in combination, the amount of heat leakage increases and the heat insulation performance decreases.
«Comparative Example 3»
In the comparative sample, two types of polyol components are used. The first polyol component A is 70% sucrose-based polyol, the second polyol component B is 30% toluene diamine-based polyol, and these are mixed. The polyol component is 100%.

  As a reaction catalyst for comparison, tetramethylhexanediamine, which is a resinated amine catalyst, is used alone. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

  In Comparative Example 3, the thermal conductivity at the thick part A was 19.6 mW / m · K, and the thermal conductivity at the thin part B was 19.9 mW / m · K. Moreover, the deterioration rate of the thermal conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 1.5%. Furthermore, the heat leak rate ratio of the heat insulating box 3 was 101 points with respect to the case where the conventional example was 100 points, and a deterioration of 1 point was recognized.

  Thus, the shoe-closed polyol, toluenediamine-based polyol, and polyester polyol specified in the present invention, and pentamethyldiethylenetriamine, triethylenediamine, N, N, N′-trimethylaminoethylethanolamine, N, N, It can be understood that when the N ', N'-tetramethylethylenediamine catalyst is not blended alone or in combination, the amount of heat leakage increases and the heat insulation performance decreases.

Thus, as shown in Comparative Examples 1 to 3, when the polyol and reaction catalyst specified in the present invention are not used, it can be understood that the amount of heat leakage increases and the heat insulation performance decreases.
≪Conventional example≫
Further, samples of conventional examples were prepared using polyurethane foam raw materials conventionally used for evaluating the above-described Examples 1 to 6 and Comparative Examples 1 to 3.

  In the conventional example, two types of polyol components are used. The first polyol component A is 70% sucrose-based polyol, the second polyol component B is 30% toluenediamine-based polyol, and these are mixed. Thus, the polyol component is 100%.

  Then, as a reaction catalyst for comparison, pentamethyldiethylenetriamine as a foaming amine catalyst, dimethylcyclohexylamine as a resinated amine catalyst, and N, N ′, N ″ -tris (3-dimethyl) as a trimerization catalyst. Three types of catalysts are used: aminopropyl) hexahydro-s-triazine. In addition, water and cyclopentane are used as the foaming agent, organic silicone is used as the foam stabilizer, and polymethylene polyphenyl diisocyanate is used as the isocyanate component.

  The heat insulation box 3 of the refrigerator which filled these forms with the polyurethane foam between the outer box 4 and the inner box 5 like Example 1 was produced. The physical properties and characteristics of the heat insulating material filled with polyurethane foam were measured in the same manner as in Example 1.

  In the conventional example, the thermal conductivity in the thick part A was 19.4 mW / m · K, and the thermal conductivity in the thin part B was 19.9 mW / m · K. Moreover, the deterioration rate of the heat conductivity by thinning from the thick part A (40 mm) to the thin part B (15 mm) was 2.6%. Then, the heat leakage amount of this conventional example was set as 100 and was used as a reference.

  As in the conventional examples and Comparative Examples 1 to 3, the shoe-closed polyol, toluenediamine-based polyol, and polyester polyol specified in the present invention, and pentamethyldiethylenetriamine, triethylenediamine, N, N, N ′ -It can be understood that when the catalyst of trimethylaminoethylethanolamine, N, N, N ', N'-tetramethylethylenediamine is not blended alone or in combination, the amount of heat leakage increases and the heat insulation performance decreases.

  In particular, in Example 5 and Example 6, since the thermal conductivity of the thick part A and the thin part B hardly changes, it can be understood that the polyurethane foam is uniformly foamed in a narrow space.

  In the above, the physical properties and characteristics of each example, comparative example, and conventional example are shown in FIG. As can be seen from the results of FIG. 2, in Examples 1 to 6, the shoe-closed polyol, toluenediamine-based polyol, and polyester polyol specified in the present invention, and pentamethyldiethylenetriamine, triethylenediamine, N, N , N'-trimethylaminoethylethanolamine, N, N, N ', N'-tetramethylethylenediamine catalyst is mixed alone or in combination, it can be seen that the heat leakage can be reduced and the heat insulation performance is improved. . In addition, it can be said in common in each example that the polyurethane foam is uniformly foamed in a narrow space, and it can be seen that the mechanical strength is also improved.

  Summarizing the present invention, the present invention is directed to a refrigerator having an occupation area ratio of 60% or more of a vacuum heat insulating material installed in a heat insulating space formed at least between an outer box and an inner box of a heat insulating box, A polyol composed of at least a three-component system in which at least a shoe-closed polyol is 60% or more, a toluenediamine-based polyol is 30% or less, and a polyester polyol is 10% or more, and a foam stabilizer, a reaction catalyst, water, A premix polyol blended with cyclopentane, pentamethyldiethylenetriamine, triethylenediamine, N, N, N'-trimethylaminoethylethanolamine, N, N, N ', N'-tetramethylethylenediamine, each alone or in combination Premix polyol blended in combination with isocyanate in refrigerator It is obtained by foaming by filling the filling space of the hot box body.

  According to this, the foaming state of the polyurethane foam in each part of the heat insulation box is stabilized by improving the fluidity of the polyurethane foam raw material and suppressing the generation of the skin layer having poor heat insulation performance. The overall thermal conductivity can be reduced and the heat insulation performance can be improved. In addition, since the fluidity is improved, a stable foamed state can be secured even in a thin portion with a small amount of polyurethane foam raw material, thereby improving the mechanical strength.

  DESCRIPTION OF SYMBOLS 1 ... Polyurethane injection head, 2 ... Polyurethane injection port, 3 ... Thermal insulation box, 4 ... Outer box, 5 ... Inner box, 6 ... Vacuum heat insulating material.

Claims (4)

In the filling space between the outer box and the inner box forming the heat insulating box, the vacuum heat insulating material is disposed so that the occupation area of the vacuum heat insulating material exceeds 60%, and the outer box of the heat insulating box and the In the refrigerator filled with polyurethane foam between the inner boxes,
The polyurethane foam comprises a polyol composed of at least a three-component system blended with at least a sucrose-based polyol at 60% or more, a toluenediamine-based polyol at 30% or less, and a polyester polyol at 10% or more, and a foam stabilizer. As a catalyst, pentamethyldiethylenetriamine, triethylenediamine, N, N, N'-trimethylaminoethylethanolamine, N, N, N ', N'-tetramethylethylenediamine are added to the premix polyol containing water and cyclopentane, respectively. Alternatively, the refrigerator is characterized in that the premix polyol blended in combination of two or more types is filled with the isocyanate into the filling space of the heat insulating box and foamed. The refrigerator according to claim 1,
The refrigerator is characterized in that at least two types of pentamethyldiethylenetriamine and triethylenediamine are combined in the remix polyol. The refrigerator according to claim 2,
The refrigerator is characterized in that, in addition to the pentamethyldiethylenetriamine and the triethylenediamine, the tetramethylethylenediamine is combined and blended in the remix polyol. The refrigerator according to claim 2,
The refrigerator is characterized in that, in addition to the pentamethyldiethylenetriamine and the triethylenediamine, the trimethylaminoethylethanolamine is combined with the remix polyol.

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