Insulation body, insulation box body, insulation door, and refrigerator

Abstract

To provide an urethane foam insulation material for a refrigerator reducing a carbon dioxide discharge amount and using a next-generation HFO-system foaming agent for achieving carbon neutral.SOLUTION: An insulation body includes a foamed polyurethane resin filled and formed in a space. The foamed polyurethane resin is formed by mixing at least a polyol component, a polyisocyanate component and a foaming agent as a hydro-fluoro-olefin having a boiling point of 15°C or lower under the atmospheric pressure so as to have about 18°C, injecting the mixture into a space, and foaming and curing the mixture.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a heat insulator having foamed polyurethane resin filled inside, an insulated box having the heat insulator, an insulated door having the heat insulator, and a refrigerator-freezer constructed from these. [Background technology]

[0002] In recent years, from the perspective of protecting the global environment, there has been a growing social demand for the development of technologies that efficiently utilize thermal energy. Against this background, efforts are being made to develop high-performance insulation technologies for refrigerator-freezers, in addition to energy-saving designs for various components and the entire device. Polyurethane foam resin is generally used as an insulation material in refrigerator-freezers.

[0003] Polyurethane foam resin is produced by adding a blowing agent to the raw materials, polyol and polyisocyanate. Previously, CFCs and HCFCs were used as blowing agents, but due to concerns about ozone depletion and global warming, foamed polyurethane resins using cyclopentane, a non-fluorocarbon, have become mainstream in recent years. However, due to the high gas thermal conductivity of cyclopentane compared to conventional fluorocarbon-based blowing agents, foamed polyurethane resins using cyclopentane as a blowing agent have a lower insulation performance than conventional foamed polyurethane resins, making it difficult to improve the insulation performance to the same level. Furthermore, the high boiling point of cyclopentane (49.3°C) compared to room temperature reduces the foaming efficiency of the urethane foam. Furthermore, the high affinity between cyclopentane and urethane resin reduces the strength of the urethane foam, making it difficult to reduce the density of foamed insulation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-2629 Summary of the Invention [Problem to be solved by the invention]

[0005] This disclosure aims to achieve carbon neutrality by reducing carbon dioxide emissions and providing a urethane foam insulation material for refrigerators that uses a next-generation HFO-based blowing agent. [Means for solving the problem]

[0006] The heat insulator of the present invention has a foamed polyurethane resin that is foamed and filled into a space. The foamed polyurethane resin is made by mixing at least a polyol component, a polyisocyanate component, and a foaming agent that is a hydrofluoroolefin having a boiling point of 15°C or less under atmospheric pressure, heating the mixture to about 18°C, injecting it into the space, and foaming and curing it. [Effects of the Invention]

[0007] The present invention suppresses vaporization of the blowing agent at room temperature and pressure, allowing the blowing agent to vaporize relatively slowly during foaming and foaming without generating large bubbles (voids), thereby improving the heat insulating performance of the foamed polyurethane resin. [Brief explanation of the drawings]

[0008] [Figure 1] Cross-sectional view of a heat-insulating door according to the first embodiment of the present invention. [Figure 2] 1 is a schematic diagram showing a method for manufacturing an insulated door according to a first embodiment of the present invention; [Figure 3] 10 is a cross-sectional view of a refrigerator-freezer according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

[0010] (Embodiment 1) Fig. 1 is a cross-sectional view of a heat-insulating door which is a heat insulator in accordance with embodiment 1 of the present invention, and Fig. 2 is a schematic diagram showing a method for manufacturing a heat-insulating door which is a heat insulator in accordance with embodiment 1 of the present invention.

[0011] As shown in Figures 1 and 2, the insulated door 101 of this embodiment is composed of an outer surface material 102 that forms the insulated door 101, an inner surface material 103, and foamed polyurethane resin 104 that is foamed in place and filled in the space between the outer surface material 102 and the inner surface material 103.

[0012] The manufacturing method of the insulated door 101 begins by mixing a first blowing agent with polyol 108. The first blowing agent is trans-1-chloro-2,3,3,3-tetrafluoropropene (HFO1224yd). HFO1224yd has a boiling point of 15°C at atmospheric pressure and a gas thermal conductivity of 9.1mW / mK at 25°C.

[0013] Next, in a mixing head 107, polyisocyanate 109 is mixed with polyol 108 mixed with HFO1224yd106, and the mixture is poured onto the outer surface material 102. Immediately thereafter, the inner surface material 103 is attached, and HFO1224yd106 is foamed in the space between the outer surface material 102 and the inner surface material 103 to form the foam.

[0014] Although not shown, foam molding is performed with the inner surface material 103 and the outer surface material 102 fixed on the opposite side of the foamed polyurethane resin 104 with a foaming jig so that the inner surface material 103 and the outer surface material 102 do not deform due to the foaming pressure of the foamed polyurethane resin 104.

[0015] Alternatively, an injection port may be provided in either the outer surface material 102 or the inner surface material 103, and the polyol 108 may be injected through the injection port into a space formed by previously attaching the outer surface material 102 and the inner surface material 103. The polyol 108 may be mixed in advance with water, a foam stabilizer, a catalyst, etc.

[0016] In the insulated door 101 of this embodiment configured as described above, the foamed polyurethane resin 104 filled and foamed in the space between the outer surface material 102 and the inner surface material 103 is formed by injecting a mixture of at least polyol 108, polyisocyanate 109, and HFO1224yd 106 having a boiling point of 15°C or less under atmospheric pressure into the space, foaming it, and hardening it.

[0017] Since HFO1224yd106, which has a lower thermal conductivity in a gaseous state than conventional cyclopentane, is used, the thermal conductivity of the foamed polyurethane resin 104 is lowered, and the thermal insulation performance of the insulating door 101 can be improved.

[0018] Although HFO1224yd106 has a boiling point of approximately 15°C, it has high solubility in the polyol 108 component of the urethane raw material, so it vaporizes relatively slowly during foaming and can foam without generating large bubbles. This improves the insulating performance of the foamed polyurethane resin 104 and the insulating performance of the insulated door 101.

[0019] If the raw material temperature in the box manufacturing process is high, the foaming agent HFO1224yd106 will vaporize at room temperature as soon as the urethane raw material is injected, causing the injected urethane raw material to turn into a hair mousse-like substance, which may take a long time to spread throughout the entire outer surface material 102, or in the worst case, may begin to harden before it has spread.

[0020] Therefore, it is necessary to inject the urethane raw material in a liquid state, which requires improving the solubility of HFO1224yd106 and the polyol component, and improving the temperature control of the raw material components.

[0021] (Embodiment 2) FIG. 3 is a schematic diagram of a refrigerator-freezer according to the second embodiment of the present invention.

[0022] The method for manufacturing the heat-insulating door of the second embodiment is the same as that of the first embodiment shown in FIG. 2, and therefore a description thereof will be omitted.

[0023] As shown in FIG. 3, the refrigerator-freezer 201 of this embodiment is composed of an insulated box body 202 having an opening in one direction, an insulated door 203 arranged to close the opening of the insulated box body 202, and a cooling device 205 that cools an enclosed space (storage chamber 204) formed by the insulated box body 202 and the insulated door 203.

[0024] The space formed by the insulated box body 202 and the insulated door 203 is used as a storage room 204 such as a vegetable room, a refrigerator room, a freezer room, etc. A plurality of insulated doors 203 are arranged to close the openings of the insulated box body 202, and a plurality of storage rooms 204 are formed.

[0025] At least the insulated door 203 of the refrigerator compartment, which is the topmost storage compartment 204 of the refrigerator-freezer 201, is composed of an outer surface material 102 that forms the door, an inner surface material 103 that is an inner surface, and foamed polyurethane resin 104 that is foam-filled and formed in the substantially closed space between the outer surface material 102 and the inner surface material 103, and the inner surface material 103 has a convex portion on the outer periphery of the surface opposite to the surface that comes into contact with the foamed polyurethane resin 104.

[0026] For ease of use, the refrigerator compartment has shelves on the insulated door 203 for placing items such as plastic bottles, glass bottles, and eggs, and the inner surface is provided with protrusions necessary for fixing the shelves. In addition to the protrusions, recesses may also be provided to fix the shelves. When the insulated door 203 is closed, the protrusions on the outer periphery fit inside the refrigerator compartment, preventing cold air from leaking to the outside. Furthermore, although not shown, it is effective to attach a gasket or the like to the outer periphery of the protrusions to prevent cold air from leaking.

[0027] The cooling device 205 is composed of a compressor 205a, a condenser 205b, an expansion means (not shown), and an evaporator 205c. An expansion means such as a capillary tube or an expansion valve is disposed between the condenser 205b and the evaporator 205c. The compressor 205a, the condenser 205b, and the evaporator 205c are connected by piping to form a refrigeration cycle. The cold air generated by this refrigeration cycle is supplied to the storage section to cool the interior.

[0028] The foamed polyurethane resin 104 is formed by foam molding using HFO1224yd106, as in the first embodiment. When filling the insulating box 202 with the raw material for the foamed polyurethane resin 104, there are generally two methods for filling the insulating box 202: a method in which an injection port is provided on the back or bottom of the insulating box 202, an opening is placed downward, and the raw material is injected downward, or a method in which the raw material is injected horizontally.

[0029] In refrigerator 201 configured as above, insulated box 202 and insulated door 203 of the present embodiment configured as above, foamed polyurethane resin 104 filled and foamed in the space between outer surface material 102 and inner surface material is formed by injecting a mixture of at least polyol 108, polyisocyanate 109, and HFO1224yd106, which is an HFO having a boiling point of 15°C or less at atmospheric pressure, into the space, foaming, and hardening.

[0030] Because HFO1224yd106, which has a lower thermal conductivity in a gaseous state than cyclopentane, which has been used conventionally, is used, the thermal conductivity of the foamed polyurethane resin 104 is lower, thereby improving the thermal insulation performance of the insulated door 203. Furthermore, although the boiling point of HFO1224yd106 is 15°C, it has a higher solubility in the polyol 108 component than cyclopentane, so it vaporizes relatively slowly during foaming and can foam without generating large bubbles (voids). This increases the thermal insulation performance of the foamed polyurethane resin 104, thereby improving the thermal insulation performance of the refrigerator-freezer 201.

[0031] Furthermore, the thermal conductivity of polyurethane foam becomes lower with HFO1224yd than with cyclopentane at lower temperatures, so it is desirable to use the polyurethane foam at a low temperature. For example, by placing the vacuum insulation material on the outer surface and the polyurethane foam on the inner surface, the polyurethane foam can be used at a temperature closer to the temperature inside the refrigerator than outside, further improving the insulation performance. [Example]

[0032] The relationship between the thermal conductivity and voids with respect to the temperature of the urethane raw material of a polyurethane foam resin applicable to a refrigerator / freezer will be described below with reference to examples and comparative examples.

[0033] The evaluation was carried out by cutting out the foamed polyurethane resin 104 from the refrigerator-freezer 201 and evaluating the thermal conductivity and voids.

[0034] The voids are air bubbles larger than the average diameter of the air bubbles in foamed polyurethane resin 104. The number of voids was measured by cutting foamed polyurethane resin 104 in the foaming direction, observing the cross section, and counting the number of voids. In the case of refrigerator-freezer 201, the foaming direction is the direction perpendicular to the wall thickness.

[0035] Examples are shown in (Table 1).

[0036] [Table 1]

[0037] The urethane raw material temperature described here refers to the temperature of the mixed polyol and polyisocyanate immediately after injection. In Examples 1 to 4, 1224 yd of HFO was used as the first blowing agent. In Comparative Example 1, the urethane raw material temperature was 22°C.

[0038] In Example 1, the urethane raw material temperature is 14°C. Compared to Comparative Example 1, in Example 1, the urethane raw material temperature is low, so there are fewer voids, but because the temperature is too low, the reaction between polyol and polyisocyanate is reduced, resulting in high thermal conductivity.

[0039] In Example 2, the urethane raw material temperature is 16°C. At this temperature, evaporation of HFO1224yd immediately after discharge can be suppressed, allowing for relatively slow foaming, resulting in fewer voids and lower thermal conductivity.

[0040] In Example 3, the urethane raw material temperature is 18°C. At this temperature, evaporation of HFO1224yd immediately after discharge can be suppressed, allowing for relatively slow foaming, resulting in fewer voids and lower thermal conductivity.

[0041] In Example 4, the urethane raw material temperature is 20° C. At this temperature, evaporation of HFO1224yd immediately after discharge can be suppressed, allowing for relatively slow foaming, resulting in fewer voids and lower thermal conductivity.

[0042] In terms of overall evaluation, Examples 2 to 4, ie, urethane raw material temperatures of 16°C or higher and 20°C or lower, are preferred.

[0043] From the above results, it can be seen that by setting the temperature of the urethane raw material at 16°C or higher and 20°C or lower, bumping during injection can be suppressed, and the generation of large bubbles and voids in the polyurethane foam 104 can be reduced, thereby suppressing the heat insulating performance of the polyurethane foam 104. This improves the heat insulating performance of the refrigerator-freezer.

[0044] Another example is shown in (Table 2).

[0045] [Table 2]

[0046] The relationship between voids and filling ability as a function of the temperature of a foaming jig applicable to a refrigerator / freezer is explained below with reference to examples and comparative examples. Filling ability refers to the ease with which a foamed polyurethane resin can be filled. If filling ability is low, there is a possibility that unfilled portions will occur.

[0047] In Comparative Example 1, the foaming jig temperature is 47° C. Because the temperature is high, HFO1224yd bumps, resulting in many voids.

[0048] In Example 5, the foaming jig temperature is 28°C. Compared to Comparative Example 1, in Example 5, the low temperature can suppress bumping of HFO1224yd and reduce voids. However, because the temperature is too low, the reaction between polyol and polyisocyanate is reduced, resulting in reduced filling properties.

[0049] In Example 6, the foaming jig temperature is 30° C. With this amount added, compared to Comparative Example 1, the temperature is lower, so bumping of HFO1224yd can be suppressed and voids can be reduced.

[0050] In Example 7, the foaming jig temperature is 35° C. Because the temperature is low, bumping of HFO1224yd can be suppressed, and voids can be reduced.

[0051] In Example 8, the foaming jig temperature is 40° C. Because the temperature is low, bumping of HFO1224yd can be suppressed, and voids can be reduced.

[0052] In Example 9, the foaming jig temperature is 45° C. Because the temperature is high, HFO1224yd bumps, resulting in many voids.

[0053] In overall evaluation, Examples 6 to 8, in other words, the foaming jig temperature of 30° C. to 40° C., are most preferable. The foaming jig temperature of Examples 6 to 9 of 30° C. to 45° C. is also acceptable.

[0054] From the above results, by setting the foaming jig temperature between 30°C and 45°C, it is possible to suppress bumping during foaming and reduce the generation of large bubbles in foamed polyurethane resin 104, thereby suppressing the heat insulating performance of foamed polyurethane resin 104. This improves the heat insulating performance of the refrigerator-freezer. [Industrial Applicability]

[0055] The present invention can reduce the thermal conductivity of foamed polyurethane resin, and is therefore applicable to refrigerators and freezers. [Explanation of symbols]

[0056] 101 Insulated Door 102 External material 103 Inner surface material 104 Polyurethane foam resin 106 HFO1224yd 108 Polyol 109 Polyisocyanate 201 Refrigerator-freezer 202 Insulated box 203 Insulated Door 204 Storage Room 205 Cooling device

Claims

1. The space is filled with foamed polyurethane resin, The foamed polyurethane resin is a heat insulator characterized in that it is produced by mixing at least a polyol component, a polyisocyanate component, and a first foaming agent which is a hydrofluoroolefin having a boiling point of 15°C or less under atmospheric pressure, heating the mixture to approximately 18°C (±2°C), injecting the mixture into the space, and foaming and curing the mixture.

2. 2. The thermal insulator according to claim 1, wherein the thermal conductivity of the first blowing agent is 11.0 mW / mK or less, which is lower than that of cyclopentane.

3. 3. The insulation of claim 1, wherein the first blowing agent is HFO 1224 yd.

4. The core density of the foamed polyurethane resin is 50 kg / m ３ 4. The thermal insulator of claim 3, wherein:

5. 5. A heat insulating box body in which the heat insulator according to claim 4 is box-shaped.

6. An insulated door comprising the insulator of claim 5.

7. 6. A refrigerator-freezer comprising a box body having an opening in one direction, a door arranged to close the opening of the box body to form an airtight space, and a cooling device that cools the airtight space formed by the box body and the door, wherein the box body is the insulated box body according to claim 5.

8. 7. A refrigerator-freezer comprising a box body having an opening in one direction, a door arranged to close the opening of the box body to form an airtight space, and a cooling device that cools the airtight space formed by the box body and the door, wherein the door is an insulated door according to claim 6.

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