JP2001133135A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator external appearance of which is improved by preventing its surface from being strained and deformed. SOLUTION: In a refrigerator provided with a heat insulator packed with rigid foamed polyurethane obtained by using at least polyol, aromatic isocyanate, and a mixed blowing agent composed of cyclopentane and water, the polyol contains three or more kinds of mixtures prepared by adding initiators respectively composed of m-tolylenediamine and o-tolylenediamine to polyol by using ethylene oxide and/or propylene oxide.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a refrigerator filled with rigid polyurethane foam.

[0002]

2. Description of the Related Art A heat insulating material using a rigid polyurethane foam having air bubbles in a space between an outer box and an inner box is used for a heat insulating box of a refrigerator. This 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. As a foaming agent, trichloromonofluoromethane, which has a low gas thermal conductivity and is hardly decomposable, has been used for a heat insulating box.

However, when released into the atmosphere, it is said that the ozone layer is depleted in the stratosphere and the surface temperature rises due to the greenhouse effect, and 1,1-dichloro-1-monofluoroethane as a substitute is used as a heat insulating material. It was used as a foaming agent, but is also subject to regulations and is scheduled to be completely abolished in 2003.

On the other hand, so-called non-fluorocarbon blowing agents, which have reduced the ozone layer depletion by not using fluorocarbons, have been used mainly in Europe as hydrocarbon-based compounds, for example, cyclopentane blowing agents, as heat insulating materials for refrigerators. . For example,
Refrigerator using rigid polyurethane foam with low density and improved fluidity using a mixed foaming agent of cyclopentane and isopentane or rigid polyurethane foam with low density and high fluidity using a mixed foaming agent of cyclopentane and water Insulated boxes and insulated doors for refrigerators and freezers have been proposed. Such a conventional technique is disclosed in Japanese Unexamined Patent Application Publication No. 11-14401.
No. 55, JP-A-11-201628 and JP-A-11-248344.

[0005]

However, hydrocarbon blowing agents such as cyclopentane and isopentane have a problem that the heat conductivity of the gas is high and the heat insulating performance is greatly inferior to conventional blowing agents. In particular, from the standpoint of global warming and protection of the global environment, the development of urethane materials that can save energy by improving heat insulation properties is demanded for rigid polyurethane foams using a mixed blowing agent of cyclopentane and water.

On the other hand, different sizes (-18 ° C, 0 ° C,
(5 ° C., 5 ° C., etc.), a refrigerator compartment is provided at the top, a vegetable compartment is provided at the middle, and an upper freezing compartment and a lower freezing compartment are provided below the compartment.

For this reason, in recent years, the space inside the cabinet wall has become narrower and more complicated due to demands for larger refrigerators and freezers and space savings, and copper pipes, aluminum tape, paper tape, polystyrene pieces, wiring, etc. There are many obstacles on the outer surface of the inner box, so that the foam does not easily flow through the inside of the refrigerator wall, and there is a problem that the filling of this portion is incomplete. To solve this problem, a urethane material having a low density and good fluidity is preferable in order to form a uniform foam in the bowl portion, the bottom portion, the back surface portion, the handle portion, and the hinge portion. For this reason, there is an urgent need to develop a urethane material which is a mixed foaming agent of cyclopentane and water, which has a low density and can reduce the thermal conductivity and secure the strength, similarly to the alternative chlorofluorocarbon.

[0008] Therefore, a low-density rigid polyurethane foam using a mixed blowing agent of cyclopentane and water has a small foam swelling amount, a small distortion deformation of an outer box surface iron plate when left at a low temperature, and a low heat resistance. It is required as a requirement for a heat insulating material that a reduction in conductivity and a compression strength and dimensional stability can be compatible.

[0009] The formation of cells foamed in the polyurethane resin involves only physical phenomena such as the generation and growth of bubbles controlled by the amount of the foaming agent, the amount of water, the catalyst and the foam stabilizer together with the chemical structure of the polyol or isocyanate. However, it is considered that the compatibility, reactivity, and fluidity during the foaming process of each raw material greatly affect the raw materials. For this reason, in order to satisfy the above requirements, optimization of each material is required.

However, the rigid polyurethane foam using a cyclopentane blowing agent has a lower saturated vapor pressure than the alternative fluorocarbon blowing agent, so that the pressure in the cells of the cells also decreases, and shrinkage after filling occurs. Easy to do. For this reason, if the filling density is too low, the deformation of the surface will occur and the yield of the product will decrease, or the strength of the box or door will decrease.

That is, in the case of a low-density rigid polyurethane foam, the expansion and contraction of the gas in the cells is affected, so that the linear expansion coefficient of the foam is increased. Here, when filling low-density rigid polyurethane foam, if the amount of filling is increased to maintain the shape as a product even if shrinkage occurs after filling, the expansion rate and swelling amount of the box or door at the time of filling are increased. Will increase. Also, until now,
Generally, high-density urethane materials have been mainly used,
Since the fluidity of the foam is inferior, a method of increasing the foaming pressure and increasing the urethane filling amount has been used to ensure the strength, but there is also a problem that the urethane foam tends to leak.

The inventors of the present invention used polyols and isocyanates as main raw materials, a foaming agent for forming air bubbles, water, a catalyst for controlling the reactivity, and a A foam stabilizer for controlling the phenomenon was studied. Specifically, the low-density rigid polyurethane foam reduces the amount of swelling during urethane foam demolding and reduces the amount of swelling even if the mold temperature fluctuates during foaming and the packing ratio fluctuates. The optimal composition of the raw material to find a rigid polyurethane foam with reduced compression ratio and excellent compressive strength and dimensional stability was variously performed, and the prospect of solving the problem was obtained.

An object of the present invention is to provide a refrigerator which is prevented from being deformed and deformed on the surface and has excellent appearance quality.

[0014]

An object of the present invention is to provide a rigid polyurethane foam in which at least a polyol, an aromatic isocyanate, and a mixed blowing agent of cyclopentane and water are used as a blowing agent in a space between an outer box and an inner box. In a refrigerator provided with a filled heat insulating material, m-
The heat insulating material is filled with the rigid polyurethane foam containing at least three components of a mixture obtained by adding an initiator consisting of tolylenediamine and o-tolylenediamine with ethylene oxide and / or propylene oxide.

Further, a mixture obtained by adding an initiator consisting of m-tolylenediamine, o-tolylenediamine, bisphenol A and triethanolamine with ethylene oxide and / or propylene oxide as the polyol component of the rigid polyurethane foam is 90%. % Of a polyether polyol having a thickness of at least about 2 mm from a plane portion at least 500 mm away from the urethane inlet.
The density of the core layer heat insulating material of 0 to 25 mm is 29 to 33 kg /
m3, thermal conductivity is 17.5 to 18.0 at an average temperature of 10 ° C.
This is achieved by using the heat insulating material having mW / m · K. Further, the aromatic isocyanate component of the rigid polyurethane foam uses a mixture of polyphenylene diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate, and further contains 1.2 to 1.6 parts by weight of water with respect to 100 parts by weight of polyol. This is achieved by using the thermal insulation material reacted in a mixed blowing agent in which 14 to 18 parts by weight of cyclopentane are combined.

The polyol component of the rigid polyurethane foam is a polyol having an OH value of 400 to 500 obtained by adding propylene oxide and ethylene oxide and propylene oxide to m-tolylenediamine.
5 to 55 parts by weight of OH obtained by adding propylene oxide and ethylene oxide to o-tolylenediamine
10-20 parts by weight of a polyol having an OH value of 450-500, and a polyol 10-20 having an OH value of 350-450 obtained by adding propylene oxide to triethanolamine.
Parts by weight, polyol 10 having an OH value of 250 to 300 obtained by adding propylene oxide to bisphenol A
To 20 parts by weight, 3 to 8 parts by weight of polyol having an OH value of 450 to 480 obtained by adding propylene oxide to diethanolamine, and OH value of trimethylolpropane to 12 parts by weight.
This is achieved by using the heat insulating material filled with a rigid polyurethane foam comprising a mixture of 2 to 5 parts by weight of 56 and having an average OH value of the polyol of 400 to 450.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have developed a low-density rigid polyurethane foam suitable for a heat insulating box used in refrigerators and freezers by reducing the amount of blister with a mixed blowing agent of cyclopentane and water. An optimal polyol was selected, which can achieve both a reduction in thermal conductivity and compressive strength and dimensional stability.

First, in order to reduce the foam swelling amount, reduce the thermal conductivity, and at the same time achieve both compressive strength and dimensional stability, an attempt was made to introduce a large amount of an initiator polyol having an aromatic ring which easily causes steric hindrance. Was.

However, when the addition polymer of the aromatic ring is used in a single component in a large amount, or when mixed with a different component such as a polyester polyol, the compatibility of the polyether polyol component is extremely reduced. . as a result,
There is a problem that turbidity is likely to occur during premixing, the varnish viscosity changes during storage stability, and the filling amount during foaming tends to fluctuate.

Therefore, as a result of examining various alkylene oxides and the amount of blister as the optimum polyol used in the present application, it has been found that those which are easily dissolved in the cyclopentane blowing agent are effective for foam blister. For this reason, an addition polymer of propylene oxide was mainly selected, and in order to make other physical properties compatible, a polyether polyol containing no heterogeneous components such as polyester polyol using ethylene oxide was also used.

Further, among aromatic rings, m-tolylenediamine is commonly used, and in order to achieve compatibility of various physical properties, m-tolylenediamine is used.
It was found that a three-component polyether polyol using an o-tolylenediamine addition polymer, which is highly reactive and expected to have cure properties, in combination with a tolylenediamine addition polymer, is effective for the amount of swelling.

However, the o-tolylenediamine adduct is
Since the varnish viscosity is higher than that of the m-tolylenediamine adduct and the reactivity is easily increased, there is a problem that voids and cracks are liable to occur when foaming is filled in the wall of the heat insulating box. For this reason, when mixing the o-tolylenediamine adduct, it is necessary to use a smaller amount than the m-tolylenediamine adduct in order to reduce the varnish viscosity and obtain a balance of reactivity. In order to improve the strength and compatibility of the amine adduct, a propylene oxide adduct and both propylene oxide and ethylene oxide adducts were used in combination.

Further, in order to obtain a balance of properties other than the initiator having an aromatic ring, bisphenol A is used as the third component.
The polymer added with propylene oxide using a triethanolamine-based initiator as the system and the fourth component was selected to be 90% or more of the optimum base component.

The isocyanate component is selected from a mixture of a commonly used polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate in order to achieve both a reduction in thermal conductivity and compressive strength and dimensional stability. The reason for this is that when polynuclear diphenylmethane diisocyanate is used, the initial reaction is slowed down, but the reaction tends to thicken rapidly when reacting, impeding flowability and coalescence association of bubbles is found to occur easily Because he did. Therefore, by mixing the prepolymer-modified tolylene diisocyanate, the thickening behavior is mild, the concentration of urethane bonds and urea bonds is increased, and the distance between crosslinking points is shortened to form uniform fine cells. Was selected.

Further, as a result of studying the optimum blending ratio of cyclopentane and water, the amount of swelling of the catalyst and the foam stabilizer, the reduction of thermal conductivity at low density, and the compatibility of compressive strength and dimensional stability, the results showed that cyclopentane The optimum mixing ratio of water and water is 1.2 to 1.6 parts by weight of water and 1 to 100 parts by weight of polyol.
Combining 4-18 parts by weight of cyclopentane, the main catalyst being trimethylaminoethylpiperazine, pentamethyldiethylenetriami and tris (3-dimethylaminopropylene) hexahydro-S-triazine such as
The present invention was completed by selecting a foam stabilizer having a low surface tension by increasing the reaction speed and curing property by using a quantification catalyst in combination.

In order to obtain a urethane material which achieves the object of the present invention, the amounts of water of the cyclopentane blowing agent and the auxiliary blowing agent are greatly affected. Further, generally, by using a large amount of cyclopentane and water in a large amount, the density can be easily reduced.

However, when the amount of water is increased, the swelling amount and the thermal conductivity are increased due to an increase in the partial pressure of carbon dioxide in the bubble cell, and when the amount of cyclopentane is increased, the compressive strength and dimensional stability are deteriorated. There is a tendency. Therefore, the optimal mixing ratio of cyclopentane and water is 1.2 to 1.6 parts by weight of water and 14 to 1 for 100 parts by weight of polyol.
It is preferred to combine 8 parts by weight of cyclopentane.

Further, as a result of examining the swelling amount of the foam, there is a tendency that the swelling amount increases as the thickness of the foam differs depending on the thickness of the heat insulating panel. It is considered that the thicker the panel, the higher the internal temperature of the foam when the heat insulating material reacts, the larger the temperature difference between expansion and contraction, and the amount of swelling increases. In addition, if urethane is injected into the boxes of the actual refrigerator and freezer and left at low temperature, there is a problem that the appearance of the iron plate on the left and right sides is easily deformed in the boxes.

The polyol used in the present invention includes:
For example, the polyhydric alcohol is a dihydric alcohol such as propylene glycol or dipropylene glycol, a trihydric alcohol such as glycerin or trimethylolpropane, or a trihydric or higher polyhydric alcohol such as diglycerin, methyl glucoside, sorbitol, or sucrose. Is mentioned. Examples of polyalkylene alkylene polyamines include ethylenediamine and diethylenetriamine; examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine, and isopropanolamine; and examples of aromatic polyamines such as 2,4-tolylenediamine and 2,3- Diaminodiphenylmethane, bisphenol A, polymethylene polyphenylpolyamine, and the like, such as tolylenediamine, 2,6-tolylenediamine, and 3,4-tolylenediamine, are used.

If the average OH value of the polyether polyol mixed composition is less than 400, the compressive strength and dimensional stability are poor, and if it exceeds 450, the foam becomes brittle.
An average OH value of 400 to 450 is a preferable result for producing a stable rigid polyurethane foam.

Examples of the reaction catalyst include tertiary amines such as trimethylaminoethylpiperazine, pentamethyldiethylenetriamine, tetramethylhexamethylenediamine, triethylenediamine and tetramethylethylenediamine, and tris (3-dimethylaminopropylene) hexahydro-S-. Trimerization catalyst such as triazine,
If the reactivity matches, such as a slow-acting catalyst used in combination with dipropylene glycol, it can be used.

The blending amount of the reaction catalyst is 10
2 to 5 parts by weight per 0 parts by weight is preferred. Further, foam stabilizers are, for example, B-8462, B-
8461, X-20-1614, F
For example, SZ-1127 manufactured by Nihon Unica Co., Ltd. has a Si molecular weight of 1800 to 3
Those which are suitable for a relatively low emulsifying action of 000 and a Si content of 25 to 30 are preferable. The compounding amount of the foam stabilizer is 1.5 to 4 parts by weight per 100 parts by weight of the polyol component.

As the isocyanate, polynuclear diphenylmethane diisocyanate and prepolymer-modified tolylene diisocyanate are mainly used. Tolylene diisocyanate is a mixture of isomers, ie, 2,4-isomer 10
0%, 2,4-form / 2, 6-form = 80/20, 65/3
5 (weight ratio) and Mitsui Cosmonate TR
C. Prepolymer urethane-modified tolylene diisocyanate, allophanate-modified tolylene diisocyanate, biuret-modified tolylene diisocyanate, isocyanurate-modified tolylene diisocyanate and the like such as Takenate 4040 manufactured by Takeda Pharmaceutical Co., Ltd. can also be used.

As the 4,4'-diphenylmethane diisocyanate, a Mitsui Cosmonate M-20 (trade name) containing a polyhedron having three or more nuclei in addition to a pure product as a main component.
0, polynuclear diphenylmethane diisocyanate such as Millionate MR manufactured by Takeda Pharmaceutical Co., Ltd. can be used. Others
Aromatic polyfunctional isocyanates such as polymethylene polyphenyl isocyanate, toluidine isocyanate, and xylylene diisocyanate, and isocyanates such as carbodiimide-modified diphenylmethane diisocyanate can also be used.

The rigid polyurethane foam of the present invention can be prepared by using a commonly used foaming machine such as P-Mart
It can be formed with a U-30 type foaming machine. The foaming conditions vary somewhat depending on the type of foaming machine, but the liquid temperature is 18-30 ° C,
Discharge pressure 80-150kg / cm2, discharge amount 15-30
kg / min, and the temperature of the mold box is preferably 35 to 45 ° C.
More preferably, the liquid temperature is 20 ° C. and the discharge pressure is 100 kg /
cm2, discharge rate 25 kg / min, mold box temperature is 45 ° C
It is near.

In this way, there are bubbles having an independent structure,
A rigid polyurethane foam using a mixed blowing agent of cyclopentane and water, the amount of swelling when filling is small,
In addition, by filling a rigid polyurethane foam, which is low in density and excellent in thermal conductivity, compressive strength, and dimensional stability, as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. Further, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator can be reduced, and a refrigerator having excellent appearance quality can be provided.

Now, the present invention will be described in detail with reference to Examples and Comparative Examples. In the following Examples and Comparative Examples, parts and% represent parts by weight and% by weight, respectively.

Example 1 As the polyol component, propylene oxide having an average hydroxyl value of 450 and m-added with propylene oxide and ethylene oxide were used.
Tolylenediamine polyetherpolyol (Polyol)
50 parts of o-tolylenediamine polyetherpolyol (referred to as Polyol B) added with propylene oxide having an average hydroxyl value of 480, and 13 parts.
15 parts of triethanolamine-based polyetherpolyol (referred to as polyol c) added with propylene oxide having an average hydroxyl value of 400, and diethanolamine-based polyetherpolyol added with propylene oxide having an average hydroxyl value of 460. 4 (referred to as polyol D)
Parts, bisphenol A-based polyetherpolyol (referred to as Polyol E) added with propylene oxide having an average hydroxyl value of 280, 15 parts, and an average hydroxyl value of 1256.
Of trimethylolpropane (referred to as Polyol F)
To 100 parts of the mixed polyol component, 16 parts of a cyclopentane blowing agent, 1.5 parts of water, 1.7 parts of trimethylaminoethylpiperazine as a reaction catalyst, 0.2 parts of pentamethyldiethylenetriamine, 0.2 parts of tris ( 3-dimethylaminopropylene) 0.4 parts of hexahydro-S-triazine, F-392 of an organic silicone as a foam stabilizer
Was blended in two parts.

137 parts of a mixture of a polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate were used as the isocyanate component. At that time, the liquid temperature of the polyol and the isocyanate was adjusted to 20 ° C. First, the polyol and the isocyanate were stirred, and the mixture was adjusted to 45.degree.
It was poured into a 5 mm aluminum mold and the amount of swelling affecting the distortion of the outer plate iron plate of the refrigerator and freezer box was measured. At this time, since the bulging amount becomes larger as the overpack becomes larger, the 75% insulated panel made of hard polyurethane foam from which the molded product is removed from the mold after 5 minutes at both the pack ratio of 115% and 125%. The swelling amount due to the change in the pack ratio was measured. Table 1 shows the results.

[0040]

[Table 1]

In this table, the physical properties of the heat insulating material (the foam swelling amount, the core layer density, the thermal conductivity, the compressive strength, the low-temperature dimensional change rate, the high-temperature dimensional change rate, the distortion before and after the test, and the distortion before and after the test) The difference in the amount and the maximum strain after the test). From Table 1, the swelling amount after 5 minutes of demolding is 2.3 mm at a pack rate of 115% and 2.7 at a pack rate of 125%.
mm, which is smaller than that of a conventional heat insulating material.

Next, an evaluation was made on a box of an actual machine using the above materials, and the results will be described below. The description will be made below with reference to the drawings.

FIG. 1 is a longitudinal sectional view in which a refrigerator compartment door 6, a vegetable compartment door 7, an upper freezer compartment door 8, and a lower freezer compartment door 9 are installed on a box 1 of a refrigerator and a freezer. First, after setting the outer box iron plate and the inner box resin wall box in a urethane foam foaming jig, the polyol and isocyanate liquid temperature is set to 20 ° C and the jig temperature is set to 45 ° C, and the rigid polyurethane foam is foamed in the voids. Fill. At that time, the polyol and the isocyanate of the urethane foam caused a chemical reaction, and the foamed urethane foam was injected and filled into the space in the wall of the box by the pressurization by the foaming pressure, thereby producing an insulated box. At that time, a zero-pack (minimum injection amount required for filling in the actual machine) of the urethane material was set in a box having an injection volume of about 200 liters, and then an overpack was injected at a 110% packing ratio.

FIG. 2 shows a schematic diagram of foaming and filling urethane at four points in a heat insulating box and a schematic diagram of collecting a urethane measurement sample. Insulation foam samples were taken from the center of the bottom of the insulation box of the refrigerator and the freezer, and various physical properties were evaluated. First, the core layer density is 200mm x 200mm x
After measuring the sample size and weight of 20 mmt, the value obtained by dividing the weight by volume and the thermal conductivity were also evaluated by using a model HC-073 (Heat Flow Method, average temperature 10 ° C.) manufactured by Eiko Seiki Co., Ltd.

The compressive strength is 50 mm × 50 mm × 20 mm
The foam sample at t was deformed at a feed rate of 4 mm / min, and the stress at the time of 10% deformation was evaluated by dividing the stress by the original pressure receiving area. Low temperature dimensional change rate and high temperature dimensional change rate are 1
50mm x 300mm x 20mmt foam -20
The rate of change in thickness when left at 24 ° C. for 24 hours or at 70 ° C. for 24 hours was evaluated.

The results are shown in Table 1. From Table 1, it can be seen that the core layer density is as low as 29.2 kg / m 3, the thermal conductivity is as low as 17.6 mW / m · K, and the compressive strength is as low as 0.
It can be seen that the change is as small as 15 MPa, the low-temperature dimensional change is -1.1%, and the high-temperature dimensional change is 1.6%.

Further, the amount of distortion of the outer steel plate is 30 mm in length.
The measurement was carried out using a strain measuring instrument having a dial gauge attached to the center of a square bar having a smooth surface of 0 mm. The measurement method is expressed by the maximum value of the distortion when the measuring instrument is applied to the outer box surface iron plate surface. For the amount of strain on the side of the box, the strain before the test is first measured and its distribution is specified, and then the container is left in a constant temperature room at -10 ° C for 48 hours. Thereafter, the sample was taken out of the constant temperature chamber and immediately measured for the amount of strain in the same manner as before the test, and the difference in the amount of strain before and after the test and the maximum strain after the test were evaluated.

Table 1 also shows these results. From Table 1, the difference between the strain amount before and after the test is 0.1 mm and the maximum strain amount is 0.3 m.
It turns out that it shows a small value as m.

Further, as a result of incorporating a refrigeration cycle component (compressor / condenser / evaporator) into a refrigerator and a freezer in which a heat insulating box in which a rigid polyurethane foam was foam-filled was formed, the amount of heat leakage was reduced by 4%. As a result, the energy consumption was reduced by about 1 kWh / month.

From the above, the rigid polyurethane foam according to the present embodiment has a small swelling amount at the time of filling, has a low density, and has excellent heat conductivity reduction, compressive strength and dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

Comparative Example 1 Polyol A60 shown in Table 1
Parts, 20 parts of polyol C, 20 parts of polyol D, 12 parts of cyclopentane blowing agent, 1.7 parts of water, 1.8 parts of tetramethylhexamethylenediamine and 0.3 parts of pentamethyldiethylenetriamine as a reaction catalyst, tris (3-dimethyl Aminopropylene) hexahydro-S-
0.5 parts of triazine, B of organic silicone as a foam stabilizer
1.846 parts of -8462 was blended. In addition, polynuclear diphenylmethane diisocyanate is used as an isocyanate.
It foamed using 0 parts. The liquid temperature of the polyol and isocyanate at that time was adjusted to 20 ° C.

First, the polyol and isocyanate were stirred and poured into a 600 × 400 × 75 mmt aluminum mold adjusted to 40 ° C.
% And 125% of the pack ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the mold was measured.

The results are shown in Table 1. From Table 1, the swelling amount after 5 minutes of demolding was 4.9 m at a pack ratio of 115%.
m, the packing ratio is 5.6 mm when the packing ratio is 125%.

Next, as in the first embodiment, after the outer case iron plate and the inner case of the refrigerator and the freezer were set on the urethane foam foaming jig, the liquid temperature of the polyol and the isocyanate was lowered to 20.
C. and a jig temperature of 40.degree. At this time, the injection volume is about 20
After setting the zero pack in a 0 liter box, the pack rate is 11
The foam was filled with 0% to produce a heat insulating box for a refrigerator and a freezer. Take a foam sample from the center of the bottom of the heat insulation box and measure the core layer density, thermal conductivity, compressive strength,
The low-temperature dimensional change rate and the high-temperature dimensional change rate were evaluated, and a low-temperature storage test (−10 ° C./48 hours) of the heat-insulating box was performed. The amount of distortion was also evaluated.

The results are shown in Table 1. From Table 1, it can be seen that the core layer density is 34.5 kg / m 3 and the thermal conductivity is 1
As high as 8.5 mW / m · K, the compressive strength is 0.11
MPa, the low-temperature dimensional change rate is -2.1%, and the high-temperature dimensional change rate is 1.8%.

Further, as a result of leaving the heat-insulating boxes of the refrigerator and the freezer at low temperature, the difference in the amount of distortion between the outer door surface iron plate before and after the distortion test was 0.22 mm, and the maximum amount of distortion after the test was 0.66 mm.
mm, and distortion deformation occurred in the outer door iron plate of the heat insulating box.

Example 2 Polyol A40 shown in Table 1
Parts, 30 parts of polyol B, 28 parts of polyol E, 2 parts of polyol F, 17 parts of cyclopentane blowing agent, 1.3 parts of water, 1.5 parts of tetramethylhexamethylenediamine and 0.2 parts of pentamethyldiethylenetriamine as a reaction catalyst, Tris 0.6 parts of (3-dimethylaminopropylene) hexahydro-S-triazine and 2.2 parts of an organic silicone B-8461 as a foam stabilizer were blended. Further, 135 parts of a polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate were foamed as isocyanates. The liquid temperature of the polyol and isocyanate at that time was adjusted to 25 ° C.

First, the polyol and isocyanate were stirred and poured into a 600 × 400 × 75 mmt aluminum mold adjusted to 40 ° C.
% And 125% of the pack ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the mold was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after minutes is 2.4 mm at a pack rate of 115% and 2.9 mm at a pack rate of 125%, which can be reduced as compared with the conventional heat insulating material.

Next, after setting the boxes of the refrigerator and the freezer in the urethane foam foaming jig in the same manner as in Example 1, the liquid temperature of the polyol and isocyanate was set at 25.degree. The foam is foam-filled in the voids. At this time, a zero-pack was set in a box having an injection volume of about 200 liters, and then foam-filled at a pack rate of 115% to produce a heat-insulated box. A heat-insulating foam sample was taken from the center of the bottom of the heat-insulating box, and the core layer density, thermal conductivity, compressive strength, low-temperature dimensional change, and high-temperature dimensional change were evaluated. Furthermore, the heat insulation box is left at low temperature (−10
(° C./48 hours) test, and the difference in the amount of strain between the outer box surface iron plate before and after the strain test and the maximum amount of strain after the test were also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is as low as 31.8 kg / m 3, the thermal conductivity is as low as 17.8 mW / m · K, and the compressive strength is 0.14.
It can be seen that the MPa, the low-temperature dimensional change rate is -1.3%, and the high-temperature dimensional change rate is as small as 1.5%.

Further, the difference in the amount of distortion between the outer box surface iron plate of the heat insulating box body before and after the strain test was 0.09 mm, and the maximum strain amount after the test was as small as 0.29 mm. Furthermore, as a result of incorporating a refrigeration cycle component (compressor / condenser / evaporator) into a refrigerator and a freezer having a heat-insulated box formed by foam-filling a rigid polyurethane foam, the amount of heat leakage was reduced by 3% and consumed. Energy consumption was reduced by about 1Kwh / month.

From the above, the rigid polyurethane foam according to the present embodiment has a small amount of swelling at the time of filling and a low density, and has a low thermal conductivity, excellent compressive strength, and excellent dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

Comparative Example 2 Polyol B60 shown in Table 1
Parts, 10 parts of polyol C, 20 parts of polyol D, and 10 parts of polyol E, 11 parts of cyclopentane blowing agent, 1.4 parts of water, 1.2 parts of tetramethylhexamethylenediamine and 0.5 part of pentamethyldiethylenetriamine as a reaction catalyst, and tris 0.6 parts of (3-dimethylaminopropylene) hexahydro-S-triazine and 1.8 parts of organic silicone B-8462 as a foam stabilizer were blended. In addition, 137 parts of a mixture of a polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate was foamed as the isocyanate.
The liquid temperature of the polyol and isocyanate at that time was adjusted to 25 ° C.

First, a polyol and an isocyanate were stirred and poured into a 600 × 400 × 75 mmt aluminum mold adjusted to 40 ° C.
% And 125% of the pack ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the mold was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after one minute increases to 4.1 mm at a pack ratio of 115% and to 5.2 mm at a pack ratio of 125%.

Next, as in the first embodiment, the outer and iron boxes of the refrigerator and the freezer were set on a urethane foam foaming jig, and the liquid temperature of the polyol and isocyanate was lowered to 25%.
C. and a jig temperature of 40.degree. At this time, the injection volume is about 20
After setting the zero pack in a 0 liter box, the pack rate is 11
Insulation boxes for refrigerators and freezers were prepared by foam filling with 5%. Take a foam sample from the center of the bottom of the heat insulation box and measure the core layer density, thermal conductivity, compressive strength,
The low-temperature dimensional change rate and the high-temperature dimensional change rate were evaluated, and a low-temperature storage test (−10 ° C./48 hours) of the heat-insulating box was performed. The amount of distortion was also evaluated.

The results are shown in Table 1. From Table 1, it can be seen that the core layer density is 35.2 kg / m 3 and the thermal conductivity is 1
As high as 8.8 mW / m · K, and the compressive strength is 0.09
It can be seen that the temperature change is as low as MPa, the low-temperature dimensional change rate is -2.3%, and the high-temperature dimensional change rate is 2.2%.

Further, as a result of performing a low-temperature storage test on the heat insulating boxes of the refrigerator and the freezer, the difference in the amount of distortion between the outer door surface iron plate before and after the distortion test was 0.16 mm, and the maximum distortion amount after the test was also 0.
It became as large as 56 mm, and distortion deformation occurred in the outer door iron plate of the heat insulating box.

Example 3 Polyol A30 shown in Table 1
18 parts of cyclopentane blowing agent, 1.2 parts of water, 1.7 parts of tetramethylhexamethylenediamine and 0.1 part of pentamethyldiethylenetriamine as a reaction catalyst in 20 parts of polyol B, 20 parts of polyol C, 20 parts of polyol C, 10 parts of polyol E, and 20 parts of polyol E. 3 parts, 0.5 part of tris (3-dimethylaminopropylene) hexahydro-S-triazine, B-8461 of an organic silicone as a foam stabilizer
Was blended in 2.2 parts. Also, polynuclear diphenylmethane diisocyanate and 140 parts of a prepolymer-modified tolylene diisocyanate were foamed as isocyanates. The liquid temperature of the polyol and isocyanate at that time is 2
The temperature was adjusted to 0 ° C. First, a polyol and an isocyanate were stirred and adjusted to 45 ° C. at 600 × 400 × 75 mmt.
Into the aluminum mold of
Using the pack ratios of 15% and 125%, the swelling amount of the rigid polyurethane foam obtained by removing the foam molded product 5 minutes after the molding was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after a minute can be reduced to 2.4 mm at a pack ratio of 115% and to 3.1 mm at a pack ratio of 125%, as compared with the conventional heat insulating material.

Next, the refrigerator and freezer boxes were set in a urethane foam foaming jig in the same manner as in Example 1, and the temperature of the polyol and isocyanate was set to 20 ° C. and the jig temperature was set to 45 ° C. The foam is foam-filled in the voids. At that time, a zero-pack was set in a box having an injection volume of about 200 liters, and then foam-filled at a pack ratio of 110% to produce a heat-insulated box. A heat-insulating foam sample was taken from the center of the bottom of the heat-insulating box, and the core layer density, thermal conductivity, compressive strength, low-temperature dimensional change, and high-temperature dimensional change were evaluated. Furthermore, the heat insulation box is left at low temperature (−10
(° C./48 hours) test, and the difference in the amount of strain between the outer box surface iron plate before and after the strain test and the maximum amount of strain after the test were also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is as low as 32.5 kg / m 3, the thermal conductivity is as low as 17.5 mW / m · K, and the compressive strength is 0.13.
It can be seen that the low-temperature dimensional change rate is as low as -1.1% and the high-temperature dimensional change rate is as low as 1.4%.

Further, the difference between the strain amount of the outer case surface iron plate of the heat insulating box body before and after the strain test was 0.07 mm, and the maximum strain amount after the test was as small as 0.27 mm. Furthermore, as a result of incorporating a refrigeration cycle component (compressor / condenser / evaporator) into a refrigerator and a freezer having a heat insulating box formed by foam filling of a rigid polyurethane foam, the amount of heat leakage was reduced by 3.5%. As a result, energy consumption was reduced by about 1 kWh / month.

From the above, the rigid polyurethane foam according to the present embodiment has a small amount of swelling at the time of filling, has a low density, and is excellent in reduction of thermal conductivity, compressive strength and dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

Example 4 Polyol A45 shown in Table 1
Parts, 15 parts of polyol B, 10 parts of polyol C, 7 parts of polyol D, 20 parts of polyol E and 3 parts of polyol F, 16 parts of cyclopentane blowing agent, 1.5 parts of water, and tetramethylhexamethylenediamine as a reaction catalyst.
5 parts, pentamethyldiethylenetriamine 0.3 part, tris (3-dimethylaminopropylene) hexahydro-S-triazine 0.5 part, and 2.2 parts of organosilicone B-8461 as a foam stabilizer were blended. Further, 132 parts of a polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate were foamed as isocyanates. The liquid temperature of the polyol and isocyanate at that time was adjusted to 20 ° C.

First, the polyol and the isocyanate were stirred and poured into a 600 × 400 × 75 mmt aluminum mold adjusted to 40 ° C.
% And 125% of the pack ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the mold was measured.

Table 1 shows the results. From Table 1, demold 5
It was found that the swelling amount after minutes was 2.6 mm at a pack rate of 115% and 3.2 mm at a pack rate of 125%, which was smaller than that of a conventional heat insulating material.

Next, after setting the boxes of the refrigerator and the freezer in the urethane foam foaming jig in the same manner as in Example 1, the liquid temperature of the polyol and isocyanate was set to 20 ° C., and the jig temperature was set to 40 ° C. The foam is foam-filled in the voids. At that time, a zero-pack was set in a box having an injection volume of about 200 liters, and then foam-filled at a pack ratio of 110% to produce a heat-insulated box. A heat-insulating foam sample was taken from the center of the bottom of the heat-insulating box, and the core layer density, thermal conductivity, compressive strength, low-temperature dimensional change, and high-temperature dimensional change were evaluated. Furthermore, the heat insulation box is left at low temperature (−10
(° C./48 hours) test, and the difference in the amount of strain between the outer box surface iron plate before and after the strain test and the maximum amount of strain after the test were also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is as low as 30.5 kg / m3, the thermal conductivity is as low as 17.9 mW / mK, and the compressive strength is also 0.16.
MPa, the low-temperature dimensional change rate was -0.9%, and the high-temperature dimensional change rate was as small as 1.6%.

Further, the difference in the amount of strain between the outer iron plate and the outer iron plate of the heat insulating box before and after the strain test was 0.08 mm, and the maximum strain after the test was a small value of 0.29 mm. Furthermore, as a result of incorporating a refrigeration cycle component (compressor / condenser / evaporator) into a refrigerator and a freezer having a heat-insulated box formed by foam-filling a rigid polyurethane foam, the amount of heat leakage was reduced by 3% and consumed. Energy consumption was reduced by about 1Kwh / month.

From the above, the rigid polyurethane foam according to the present embodiment has a small amount of swelling at the time of filling, has a low density, and has excellent heat conductivity reduction, compressive strength and dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

Comparative Example 3 20 parts of m-tolylenediamine-based polyether polyol A, 30 parts of polyol B, 10 parts of polyol C, 10 parts of polyol D, 20 parts of polyol E and 10 parts of polyol F added with propylene oxide shown in Table 1 13 pentane blowing agent
Parts, water 1.1 parts, tetramethylhexamethylenediamine 1.8 parts as reaction catalyst and pentamethyldiethylenetriamine 0.3 parts, tris (3-dimethylaminopropylene) hexahydro-S-triazine 0.3 parts, foam stabilizer 1.8 parts of organic silicone B-8462 was blended. Further, 135 parts of polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate were foamed as isocyanates. The liquid temperature of the polyol and isocyanate at that time was adjusted to 20 ° C.

First, the polyol and the isocyanate were stirred and poured into a 600 × 400 × 75 mmt aluminum mold adjusted to 45 ° C.
% And 125% of the pack ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the mold was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after one minute increases to 4.5 mm at a pack ratio of 115% and 5.5 mm at a pack ratio of 125%.

Next, as in the case of Example 1, after the outer box iron plate and inner box of the refrigerator and the freezer were set on the urethane foam foaming jig, the liquid temperature of the polyol and isocyanate was lowered to 20.
C. and the jig temperature are set to 45.degree. At this time, the injection volume is about 20
After setting the zero pack in a 0 liter box, the pack rate is 11
Insulation boxes for refrigerators and freezers were prepared by foam filling with 5%. Take a foam sample from the center of the bottom of the heat insulation box and measure the core layer density, thermal conductivity, compressive strength,
The low-temperature dimensional change rate and the high-temperature dimensional change rate were evaluated, and a low-temperature storage test (−10 ° C./48 hours) of the heat-insulating box was performed. The amount of distortion was also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is 35.8 kg / m 3 and the thermal conductivity is 1
8.3mW / m · K, as high as 0.12
It can be seen that MPa, the low-temperature dimensional change rate is -1.9%, and the high-temperature dimensional change rate is 2.1%, which are large values.

Further, as a result of performing a low-temperature storage test of the heat insulating boxes of the refrigerator and the freezer, the difference in the amount of distortion between the outer door and front iron plate before and after the distortion test was 0.15 mm, and the maximum distortion after the test was also 0.
As a result, the outer door iron plate of the heat-insulating box was deformed and deformed.

Example 5 Polyol A30 shown in Table 1
Parts, 20 parts of polyol B, 20 parts of polyol C, 10 parts of polyol D, and 20 parts of polyol E, 14 parts of cyclopentane blowing agent, 1.6 parts of water, 1.5 parts of tetramethylhexamethylenediamine and 0.1 part of pentamethyldiethylenetriamine as a reaction catalyst. 3 parts, 0.5 part of tris (3-dimethylaminopropylene) hexahydro-S-triazine, B-8461 of an organic silicone as a foam stabilizer
Was blended in 2.2 parts. Also, polynuclear diphenylmethane diisocyanate and 140 parts of a prepolymer-modified tolylene diisocyanate were foamed as isocyanates. The liquid temperature of the polyol and isocyanate at that time is 2
The temperature was adjusted to 0 ° C.

First, the polyol and the isocyanate were stirred and poured into a 600 × 400 × 75 mmt aluminum mold adjusted to 40 ° C.
% And 125% of the pack ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the mold was measured.

Table 1 shows the results. From Table 1, demold 5
It was found that the swelling amount after min was 2.4 mm at a pack ratio of 115% and 2.9 mm at a pack ratio of 125%, which was smaller than that of a conventional heat insulating material.

Next, after setting the boxes of the refrigerator and the freezer in the foaming jig of urethane foam in the same manner as in Example 1, the liquid temperature of the polyol and isocyanate was set at 20 ° C., and the jig temperature was set. At 40 ° C., the rigid polyurethane foam is foam-filled in the voids. At that time, a zero-pack was set in a box having an injection volume of about 200 liters, and then foam-filled at a pack ratio of 110% to produce a heat-insulated box. A heat insulating foam sample was taken from the center of the bottom of the heat insulating box, and the core layer density, thermal conductivity, compressive strength, low-temperature dimensional change, and high-temperature dimensional change were evaluated.

Further, the heat insulating box was left at low temperature (−10 ° C. /
(48 hours) A test was performed, and the difference in the amount of distortion between before and after the distortion test of the outer steel plate and the maximum amount of distortion after the test were also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is as low as 32 kg / m 3, the thermal conductivity is as low as 18 mW / m · K, the compressive strength is as high as 0.12 MPa, the low-temperature dimensional change rate is -0.8%, and the high-temperature dimensional change. The ratio showed a small value of 1.5%. Further, the difference in the amount of distortion between the outer box surface iron plate before and after the distortion test of the outer insulation box body was 0.09 mm, and the maximum distortion amount after the test was a small value of 0.26 mm.

Further, a refrigerator and a freezer in which a heat insulating box was formed by foam-filling a rigid polyurethane foam and a refrigeration cycle component (compressor / condenser / evaporator) was incorporated and measured. The energy consumption was reduced by 4% and the power consumption was reduced by about 1 kWh / month.

From the above, the rigid polyurethane foam according to the present embodiment has a small amount of swelling at the time of filling, has a low density, and is excellent in reduced heat conductivity, compressive strength and dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

Comparative Example 4 25 parts of m-tolylenediamine polyetherpolyol A and 35 parts of polyol B added with propylene oxide shown in Table 1 and 35 parts of polyol
14 parts of cyclopentane blowing agent, 1.0 part of water and 1.2 parts of tetramethylhexamethylenediamine as a reaction catalyst were added to 20 parts of C, 10 parts of D and 5 parts of F.
Part and pentamethyldiethylenetriamine 0.5 part, tris (3-dimethylaminopropylene) hexahydro-S
-0.5 part of triazine and 1.8 parts of organic silicone B-8462 as a foam stabilizer were blended. Also, isocyanate
The polynuclear body of diphenylmethane diisocyanate and the prepolymer-modified tolylene diisocyanate were foamed using 140 parts. Polyol and isocyanate at that time
The liquid temperature of the sample was adjusted to 20 ° C.

First, the polyol and isocyanate were stirred and poured into an aluminum mold of 600 × 400 × 75 mmt adjusted to 40 ° C.
% And 125% of the packing ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the molding was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after one minute increases to 4.8 mm at a pack ratio of 115% and to 5.7 mm at a pack ratio of 125%.

Next, as in the first embodiment, after the outer box iron plate and inner box of the refrigerator and the freezer were set on the urethane foam foaming jig, the liquid temperature of the polyol and the isocyanate was set at 20.
C. and the jig temperature are set to 40.degree. C., and the rigid polyurethane foam is foam-filled in the voids. At this time, the injection volume is about 20
After setting the zero pack in a 0 liter box, the pack rate is 11
The foam was filled with 0% to produce a heat insulating box for a refrigerator and a freezer. A heat insulating foam sample was taken from the center of the bottom of the heat insulating box, and the core layer density, thermal conductivity, compressive strength,
The low-temperature dimensional change rate and the high-temperature dimensional change rate were evaluated, and a low-temperature storage test (−10 ° C./48 hours) of the heat-insulating box was performed. The amount of distortion was also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is 35.5 kg / m3 and the thermal conductivity is 1
As high as 8.4 mW / mK, the compressive strength is 0.11
It has a low value of MPa, a low-temperature dimensional change rate of -1.8%, and a high-temperature dimensional change rate of 1.9%.

Further, as a result of performing a low-temperature storage test on the heat insulating boxes of the refrigerator and the freezer, the difference in the amount of distortion between the outer door surface iron plate before and after the distortion test was 0.19 mm, and the maximum distortion amount after the test was 0.19 mm.
As a result, the outer door iron plate of the heat-insulating box was deformed and deformed.

Example 6 Polyol A40 shown in Table 1
Part, Polyol B23 part, Polyol C15 part, Polyol D5 part, Polyol E15 part and Polyol F2
15 parts of cyclopentane blowing agent, 1.4 parts of water, 1.5 parts of tetramethylhexamethylenediamine and 0.2 parts of pentamethyldiethylenetriamine as a reaction catalyst.
Parts, tris (3-dimethylaminopropylene) hexahydro-S-triazine, 0.4 part, and 2.2 parts of an organic silicone, B-8461, as a foam stabilizer. Further, as the isocyanate, polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate may be used.
It foamed using 35 parts. At that time, the liquid temperature of the polyol and the isocyanate was adjusted to 20 ° C.

First, the polyol and the isocyanate were stirred and poured into an aluminum mold of 600 × 400 × 75 mmt adjusted to 45 ° C.
% And 125% of the packing ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the molding was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after minutes can be reduced to 2.6 mm at a pack rate of 115% and 3.1 mm at a pack rate of 125%, as compared with the conventional heat insulating material.

Next, after setting the boxes of the refrigerator and the freezer in the urethane foam foaming jig in the same manner as in the first embodiment, the liquid temperature of the polyol and isocyanate was set at 20 ° C., and the jig temperature was set. At 45 ° C., the rigid polyurethane foam is foam-filled in the voids. At this time, a zero-pack was set in a box having an injection volume of about 200 liters, and then foam-filled at a pack rate of 115% to produce a heat-insulated box. A heat insulating foam sample was taken from the center of the bottom of the heat insulating box, and the core layer density, thermal conductivity, compressive strength, low-temperature dimensional change, and high-temperature dimensional change were evaluated. Furthermore, the heat insulation box is left at low temperature (−10
(° C./48 hours) test, and the difference in the amount of strain between the outer box surface iron plate before and after the strain test and the maximum amount of strain after the test were also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is as low as 31.5 kg / m 3, the thermal conductivity is as low as 17.9 mW / m · K, and the compressive strength is 0.15.
MPa, the low-temperature dimensional change rate was -1.2%, and the high-temperature dimensional change rate was as small as 1.3%. In addition, the difference in the amount of distortion between the outer box surface iron plate before and after the distortion test of the heat insulating box body was 0.08 m.
m, the maximum strain after the test also showed a small value of 0.27 mm.

Further, as a result of incorporating a refrigeration cycle component (compressor / condenser / evaporator) into a refrigerator and a freezer having a heat-insulated box formed by foam-filling a rigid polyurethane foam, the amount of heat leakage was found to be small. The energy consumption was reduced by 3% and the power consumption was reduced by about 1 kWh / month.

From the above, the rigid polyurethane foam according to the present embodiment has a small swelling amount at the time of filling and a low density, and is excellent in reduced thermal conductivity, compressive strength and dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

Example 7 Polyol A40 shown in Table 1
Parts, 20 parts of Polyol B, 20 parts of Polyol C, 10 parts of Polyol D, and 10 parts of Polyol E, 16 parts of cyclopentane blowing agent, 1.5 parts of water and tetramethylhexamethylenediamine as a reaction catalyst. 5 parts, pentamethyldiethylenetriamine 0.3 part, tris (3-dimethylaminopropylene) hexahydro-S-triazine 0.5 part, an organic silicone B-8461 as a foam stabilizer
Was blended in 2.2 parts. In addition, polynuclear diphenylmethane diisocyanate and 140 parts of a prepolymer-modified tolylene diisocyanate were foamed as isocyanates. At this time, the liquid temperature of the polyol and isocyanate was 2
The temperature was adjusted to 0 ° C.

First, the polyol and isocyanate were stirred and poured into an aluminum mold of 600 × 400 × 75 mmt adjusted to 45 ° C.
% And 125% of the packing ratio, the swelling amount of the rigid polyurethane foam from which the foam molded article was released after 5 minutes from the molding was measured.

Table 1 shows the results. From Table 1, demold 5
It can be seen that the swelling amount after minutes is 2.3 mm at a pack ratio of 115% and 2.8 mm at a pack ratio of 125%, which can be reduced as compared with the conventional heat insulating material.

Next, as in the case of the first embodiment, the boxes of the refrigerator and the freezer were set on a foaming jig of urethane foam, and the temperature of the liquid of polyol and isocyanate was set at 20 ° C., and the temperature of the jig was adjusted. At 45 ° C., the rigid polyurethane foam is foam-filled in the voids. At that time, a zero-pack was set in a box having an injection volume of about 200 liters, and then foam-filled at a pack ratio of 110% to produce a heat-insulated box. A heat insulating foam sample was taken from the center of the bottom of the heat insulating box, and the core layer density, thermal conductivity, compressive strength, low-temperature dimensional change, and high-temperature dimensional change were evaluated. Furthermore, the heat insulation box is left at low temperature (−10
(° C./48 hours) test, and the difference in the amount of strain between the outer box surface iron plate before and after the strain test and the maximum amount of strain after the test were also evaluated.

The results are shown in Table 1. From Table 1, the core layer density is as low as 32.9 kg / m3, the thermal conductivity is as low as 17.8 mW / mK, and the compressive strength is also 0.14.
It can be seen that the low-temperature dimensional change rate is as low as 1.4% and the high-temperature dimensional change rate is as low as 1.1%.

Further, the difference between the strain amount of the outer case surface iron plate before and after the strain test was 0.07 mm, and the maximum strain amount after the test was as small as 0.29 mm. Furthermore, as a result of incorporating a refrigeration cycle component (compressor / condenser / evaporator) into a refrigerator and a freezer having a heat-insulated box formed by foam-filling a rigid polyurethane foam, the amount of heat leakage was reduced by 3%. As a result, the energy consumption was reduced by about 1 kWh / month.

From the above, the rigid polyurethane foam according to the present example has a small amount of swelling at the time of filling and a low density, and has excellent heat conductivity reduction, compressive strength and dimensional stability. Becomes Also,
By filling the rigid polyurethane foam according to the present embodiment as a heat insulating material for a refrigerator, the amount of heat leakage can be reduced and the power consumption can be reduced. Further, the filling amount of the heat insulating material is reduced, and the cost of the refrigerator can be reduced. In addition, even if the refrigerator is left at a low temperature, distortion deformation of the refrigerator is reduced, and the appearance quality of the refrigerator is improved.

[0117]

According to the present invention, it is possible to provide a refrigerator excellent in appearance quality by preventing surface distortion deformation.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a heat insulating material in which a heat insulating box and a heat insulating door of a refrigerator and a freezer are filled with urethane.

FIG. 2 is a schematic diagram of foaming and filling urethane at four points in a heat insulating box and a schematic diagram of collecting a urethane measurement sample.

[Explanation of symbols]

1 ... refrigerator body, 2 ... inner box, 3 ... refrigerator compartment,
4 ... vegetable room, 5 ... freezer room, 6 ... refrigerator compartment door, 7
... Vegetable compartment door, 8 ... Upper freezer compartment door, 9 ... Lower freezer compartment door, 10 ... Urethane insulation material, 11 ... Urethane injection head, 12 ... Urethane flow, 13 ... Urethane injection port, 14 ... Sample collection position

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Atsushi Komuro, 800, Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Inside the Refrigeration Division, Hitachi, Ltd. (72) Hisao Yokokura 7-1-1, Omika-cho, Hitachi, Ibaraki Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Yutaka Ito 7-1-1, Omikacho, Hitachi City, Ibaraki Prefecture Within Hitachi Research Laboratory, Hitachi, Ltd. (72) Inventor Masayoshi Sugano 7, Omikamachi, Hitachi City, Ibaraki Prefecture No. 1-1 F-term in Hitachi Research Laboratory, Hitachi, Ltd. F-term (reference) 3L102 MB17 4F074 AA79 AA83 AA84 BA34 BA39 BB23 BC05 CA25 DA02 DA07 DA08 DA23 DA32 4J034 BA07 BA08 CA02 CA03 CA04 CA05 CA13 CA15 CA16 CA17 CB03 CB04 CB05 CB07 CB04 CB05 CB07 CC03 CC08 CC12 CC61 CC65 CC66 CC67 CD01 CD04 DG03 DG04 DG08 DG09 DG14 DG16 DG22 HA01 HA02 HA06 HA07 HB06 HB07 HB08 H C12 HC26 HC35 HC46 HC61 HC63 HC64 HC67 HC71 HC73 KA01 KB02 KD12 KE02 NA01 NA03 NA06 QA02 QB01 QB16 QB19 QC01 RA15

Claims (4)

[Claims] 1. A refrigerator comprising a heat insulating material filled in a space between an outer box and an inner box with a rigid polyurethane foam using at least a mixed blowing agent of cyclopentane and water as a foaming agent with an aromatic isocyanate and a foaming agent. A mixture obtained by adding an initiator consisting of m-tolylenediamine and o-tolylenediamine as a polyol component with ethylene oxide and / or propylene oxide;
A refrigerator comprising the heat insulating material filled with a rigid polyurethane foam containing at least one component. 2. A mixture obtained by adding an initiator consisting of m-tolylenediamine, o-tolylenediamine, bisphenol A and triethanolamine with ethylene oxide and / or propylene oxide as the polyol component of the rigid polyurethane foam. % Of a polyether polyol having a thickness of at least about 20 to 25 from a plane portion at least 500 mm away from the urethane inlet.
mm core layer heat insulating material has a density of 29 to 33 kg / m3 and a thermal conductivity of 17.5 to 18.0 mW / m at an average temperature of 10C.
The refrigerator according to claim 1, further comprising the heat insulating material having K. 3. An aromatic isocyanate component of the rigid polyurethane foam is a mixture of polynuclear diphenylmethane diisocyanate and a prepolymer-modified tolylene diisocyanate, and 1.2 to 1.6 parts by weight based on 100 parts by weight of polyol. The refrigerator according to claim 2, further comprising the heat insulating material obtained by reacting water in a mixed blowing agent obtained by combining 14 to 18 parts by weight of cyclopentane. 4. The polyol component of the rigid polyurethane foam is a polyol having an OH value of 400 to 500 obtained by adding propylene oxide and ethylene oxide and propylene oxide to m-tolylenediamine.
5 to 55 parts by weight of OH obtained by adding propylene oxide and ethylene oxide to o-tolylenediamine
10 to 20 parts by weight of a polyol having an OH value of 450 to 500, and a polyol 10 to 20 having an OH value of 350 to 450 obtained by adding propylene oxide to triethanolamine.
Parts by weight, polyol 10 having an OH value of 250 to 300 obtained by adding propylene oxide to bisphenol A
To 20 parts by weight, 3 to 8 parts by weight of a polyol having an OH value of 450 to 480 obtained by adding propylene oxide to diethanolamine, and trimethylolpropane OH value of 12
The refrigerator according to claim 3, comprising the mixture of 2 to 5 parts by weight of 56, and the heat insulating material filled with a rigid polyurethane foam having an average OH value of the polyol of 400 to 450.