Foaming material and refrigeration device

Abstract

The embodiment of the invention provides a foaming material and a refrigerating device. The foaming material comprises the following components in parts by weight: 80-120 parts of combined polyether, 12-20 parts of a first foaming agent and 130-160 parts of isocyanate, wherein the first foaming agent comprises a high-boiling-point alkane foaming agent and a low-boiling-point alkane foaming agent, the mass ratio of the high-boiling-point alkane foaming agent to the low-boiling-point alkane foaming agent is 10: (3-10), the high-boiling-point alkane foaming agent comprises cyclopentane, and the low-boiling-point alkane foaming agent comprises at least one of isopentane and propylene. The foaming material provided by the embodiment of the invention can be used for preparing a thermal insulation layer of a refrigerator, the first foaming agent of the foaming material adopts a mixture of a high-boiling-point alkane foaming agent and a low-boiling-point alkane foaming agent, the obtained foaming material has relatively low molding density, and under the condition that the volume of the thermal insulation layer is kept to be certain, the molding density is relatively high; by reducing the density, the mass of the used foaming material can be reduced, namely, the use amount of the foaming material can be reduced, so that the production cost of the refrigerator can be reduced.

Description

Technical Field

[0001] The present application relates to the field of polymer materials, and in particular to a foaming material and a refrigeration device. Background Art

[0002] With the improvement of people's living standards, refrigerators have become one of the indispensable electrical appliances in modern family life. The refrigerator body and door are usually equipped with an insulation layer, which can isolate the temperature exchange between the inside and outside of the refrigerator and prevent the external temperature from affecting the internal temperature of the refrigerator, thereby maintaining the internal temperature of the refrigerator constant, reducing the working times of the compressor, and achieving the purpose of energy saving.

[0003] The material of the heat-insulating layer is usually a foam material. However, the molding density of the existing foam material is relatively high, which results in a large amount of foam material used in the refrigerator, and further leads to a high production cost of the refrigerator. Summary of the invention

[0004] Based on this, an embodiment of the present application provides a foaming material and a refrigeration device.

[0005] In a first aspect, an embodiment of the present application provides a foaming material, which comprises, by weight: 80 to 120 parts of a combined polyether, 12 to 20 parts of a first foaming agent, and 130 to 160 parts of an isocyanate;

[0006] Wherein, the first foaming agent comprises a high boiling point alkane foaming agent and a low boiling point alkane foaming agent in a mass ratio of 10:(3-10), the high boiling point alkane foaming agent comprises cyclopentane, and the low boiling point alkane foaming agent comprises at least one of isopentane and propylene.

[0007] In some embodiments, the combined polyether includes, by weight, 30-50 parts of polyether polyol, 20-40 parts of polyester polyol, 20-40 parts of polymer polyol, 4-6 parts of catalyst, 1-2 parts of foam stabilizer, 15-25 parts of flame retardant, 15-20 parts of second foaming agent and 1-3 parts of water.

[0008] In some embodiments, the polymer polyol includes at least one of POP36 / 28, HPOP40, POP93 / 28 and EP3600; and / or,

[0009] The polyether polyol includes at least one of Puranol RF4110A, Puranol RF8310, Puranol RF6282, Puranol RF6482, Donol C305 and Donol 204E; and / or,

[0010] The polyester polyol is an aromatic polyester polyol.

[0011] In some embodiments, the functionality of the aromatic polyester polyol is 2-3, the hydroxyl value of the aromatic polyester polyol is 200KOH / g-250mgKOH / g, and the viscosity of the aromatic polyester polyol is 3000mPa·s-4500mPa·s.

[0012] In some embodiments, the catalyst comprises at least one of POLYACAT 303, POLYACAT 8, Dabco BX405, K15, POLYCAT 41, and DABCOT; and / or,

[0013] The foam stabilizer comprises at least one of M-6688LV, M-6680 and AK-8860; and / or,

[0014] The flame retardant comprises at least one of TCPP, TEP and TCEP; and / or,

[0015] The second blowing agent includes HFC-245fa.

[0016] In some embodiments, the isocyanate comprises polymethylene polyphenyl isocyanate.

[0017] In some embodiments, the viscosity of the polymethylene polyphenyl isocyanate is 180 mPa·s to 220 mPa·s, and the isocyanate content of the polymethylene polyphenyl isocyanate is 30 wt % to 32.2 wt %.

[0018] In some embodiments, the foaming material includes, by weight: 100 parts of combined polyether, 16 parts of first foaming agent and 145 parts of isocyanate.

[0019] In a second aspect, an embodiment of the present application provides a refrigeration device, comprising a thermal insulation layer, wherein the thermal insulation layer comprises the foaming material as described above.

[0020] In some embodiments, the refrigeration device includes a box body, the box body includes a shell and a box liner, the box liner is arranged on the inner side of the shell, and the insulation layer is arranged between the shell and the box liner.

[0021] In some embodiments, the refrigeration device includes a door body, and the door body includes a door panel and a door liner that are spaced apart, and the insulation layer is provided between the door panel and the door liner.

[0022] The foaming material provided in the embodiment of the present application can be used to prepare the insulation layer of the refrigerator. The first foaming agent of the foaming material adopts a mixture of a high-boiling point alkane foaming agent and a low-boiling point alkane foaming agent. The obtained foaming material has a smaller molding density. While the volume of the insulation layer remains constant, the mass of the foaming material used can be reduced by reducing the density. In other words, the amount of foaming material used can be reduced, thereby reducing the production cost of the refrigerator. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present application are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0024] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0026] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0027] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0028] The embodiment of the present application provides a foaming material, which comprises, by weight: 80 to 120 parts of a combined polyether, 12 to 20 parts of a first foaming agent, and 130 to 160 parts of an isocyanate;

[0029] Wherein, the first foaming agent includes a high-boiling point alkane foaming agent and a low-boiling point alkane foaming agent in a mass ratio of 10:(3-10), the high-boiling point alkane foaming agent includes cyclopentane (CP), and the low-boiling point alkane foaming agent includes at least one of isopentane (IP) and propylene.

[0030] The foaming material of the embodiment of the present application needs to be mixed under a pressure of 3-5 bar before use, and then injected into a mold (such as a refrigerator body or a refrigerator door, etc.) using a gun tip to react the combined polyether and isocyanate into polyurethane foam. During the reaction, the first foaming agent evaporates to form pores. Since the polyurethane foam is a hard foam, it will form a closed cell rate of more than 95%. The pores will lock the foaming agent to prevent the foaming agent from evaporating and escaping.

[0031] For example, in parts by weight, the amount of the combined polyether in the foaming material may be 80 parts, 85 parts, 90 parts, 95 parts, 100 parts, 105 parts, 110 parts, 115 parts, 120 parts, etc.

[0032] Illustratively, in parts by weight, the amount of the first foaming agent in the foaming material may be 12 parts, 12 parts, 13 parts, 14 parts, 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, etc.

[0033] For example, in parts by weight, the amount of the isocyanate in the foaming material may be 130 parts, 135 parts, 140 parts, 145 parts, 150 parts, 155 parts, 160 parts, etc.

[0034] In some embodiments, the foaming material includes, by weight: 100 parts of combined polyether, 16 parts of first foaming agent and 145 parts of isocyanate.

[0035] Illustratively, in the first foaming agent, the mass ratio of the high-boiling-point alkane foaming agent to the low-boiling-point alkane foaming agent may be 10:3, 10:4, 10:5, 10:6, 10:7, 10:8, 10:9, 1:1, etc.

[0036] Exemplarily, when the low-boiling point alkane blowing agent comprises isopentane and propylene at the same time, the mass ratio of isopentane to propylene is 5:(1-5), such as 5:1, 5:2, 5:3, 5:4, 1:1, etc.

[0037] The foaming material provided in the embodiment of the present application can be used to prepare the insulation layer of the refrigerator. The first foaming agent of the foaming material adopts a mixture of a high-boiling point alkane foaming agent and a low-boiling point alkane foaming agent. The obtained foaming material has a smaller molding density. While the volume of the insulation layer remains constant, the mass of the foaming material used can be reduced by reducing the density. In other words, the amount of foaming material used can be reduced, thereby reducing the production cost of the refrigerator.

[0038] Illustratively, in parts by weight, the combined polyether includes 30-50 parts of polyether polyol, 20-40 parts of polyester polyol, 20-40 parts of polymer polyol, 4-6 parts of catalyst, 1-2 parts of foam stabilizer, 15-25 parts of flame retardant, 15-20 parts of second foaming agent and 1-3 parts of water.

[0039] Illustratively, in the combined polyether, the number of polyether polyols may be 30 parts, 35 parts, 40 parts, 45 parts, 50 parts, etc., the number of polyester polyols may be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc., the number of polymer polyols may be 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc., the number of catalysts may be 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, etc., the number of foam stabilizers may be 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, etc., the number of flame retardants may be 15 parts, 18 parts, 20 parts, 22 parts, 25 parts, the number of second foaming agents may be 15 parts, 16 parts, 17 parts, 18 parts, 19 parts, 20 parts, and the number of water may be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.

[0040] For example, the polymer polyol includes at least one of POP36 / 28, HPOP40, POP93 / 28 and EP3600. For example, Puranol RF4110A, PuranolRF8310, Puranol RF6282 and Puranol RF6482 are all purchased from PolyOne Corporation of the United States, and Donol C305 and Donol 204E are purchased from Shanghai Dongda Chemical Co., Ltd.

[0041] Illustratively, the polyether polyol includes at least one of Puranol RF4110A, Puranol RF8310, Puranol RF6282, Puranol RF6482, Donol C305 and Donol 204E. Illustratively, POP36 / 28, HPOP40, POP93 / 28 and EP3600 are all purchased from Jiahua Chemical Co., Ltd.

[0042] Exemplarily, the polyester polyol is an aromatic polyester polyol.

[0043] Illustratively, the functionality of the aromatic polyester polyol is 2 to 3, such as 2, 2.2, 2.5, 2.8, 3, and the like.

[0044] Illustratively, the hydroxyl value of the aromatic polyester polyol is 200KOH / g to 250mgKOH / g, for example, 200KOH / g, 210KOH / g, 220KOH / g, 230KOH / g, 240KOH / g, 250mgKOH / g, etc.

[0045] Illustratively, the viscosity of the aromatic polyester polyol is 3000 mPa·s to 4500 mPa·s, for example, 3000 mPa·s, 3200 mPa·s, 3500 mPa·s, 3800 mPa·s, 4000 mPa·s, 4200 mPa·s, 4500 mPa·s, etc.

[0046] Illustratively, the aromatic polyester polyol is purchased from Jiahua Chemical Co., Ltd.

[0047] Exemplarily, the catalyst includes at least one of POLYACAT 303, POLYACAT 8, Dabco BX405, K15, POLYCAT 41 and DABCOT. Exemplarily, POLYACAT 303, POLYACAT 8, Dabco BX405, K15, POLYCAT 41 and DABCOT are all purchased from Xindian Chemical Materials (Shanghai) Co., Ltd.

[0048] Exemplarily, the foam stabilizer includes at least one of M-6688LV, M-6680 and AK-8860. Exemplarily, M-6688LV, M-6680 and AK-8860 are all purchased from Weifang Huapu Chemical Co., Ltd.

[0049] Exemplarily, the flame retardant includes at least one of TCPP, TEP and TCEP. Exemplarily, TCPP, TEP and TCEP are all purchased from Taizhou Ruishite New Materials Co., Ltd.

[0050] Exemplarily, the second blowing agent includes HFC-245fa. Exemplarily, HFC-245fa is purchased from Sinochem Blue Sky Honeywell New Materials Co., Ltd.

[0051] Exemplarily, the water is deionized water.

[0052] Illustratively, the water content of the composite polyether is 1.5 wt% to 3.1 wt%, for example, 1.5 wt%, 1.7 wt%, 2.0 wt%, 2.3 wt%, 2.5 wt%, 2.8 wt%, 3.0 wt%, 3.1 wt%, etc.

[0053] Illustratively, the viscosity of the combined polyether is 5500 mPa·s to 6100 mPa·s, for example, 5500 mPa·s, 5600 mPa·s, 5800 mPa·s, 6000 mPa·s, 6100 mPa·s, etc.

[0054] Exemplarily, the isocyanate includes polymethylene polyphenyl isocyanate.

[0055] Exemplarily, the viscosity of the polymethylene polyphenyl isocyanate is 180 mPa·s to 220 mPa·s, for example, 180 mPa·s, 190 mPa·s, 200 mPa·s, 210 mPa·s, 220 mPa·s, etc.

[0056] Illustratively, the isocyanate (HNCO) content of the polymethylene polyphenyl isocyanate is 30 wt% to 32.2 wt%, for example, 30 wt%, 30.5 wt%, 31.1 wt%, 31.6 wt%, 32.2 wt%, and the like.

[0057] Illustratively, the polymethylene polyphenyl isocyanate is purchased from Wanhua Chemical Group Co., Ltd.

[0058] An embodiment of the present application further provides a refrigeration device, comprising a thermal insulation layer, wherein the thermal insulation layer comprises the foaming material as described above.

[0059] Exemplarily, the refrigeration device may be a refrigerator, a freezer, a cold drink machine, a refrigerated wine cabinet, a freezer, an ice cream machine, an ice maker, etc.

[0060] Exemplarily, the refrigeration device includes a box body, the box body includes a shell and a box liner, the box liner is arranged on the inner side of the shell, and the insulation layer is arranged between the shell and the box liner.

[0061] Exemplarily, the refrigeration device includes a door body, the door body includes a door panel and a door liner that are spaced apart, and the thermal insulation layer is provided between the door panel and the door liner.

[0062] The foaming material of the present application is described in detail below in the form of specific embodiments.

[0063] Example 1

[0064] A foaming material, comprising, by weight, 100 parts of a combined polyether, 16 parts of a first foaming agent, and 145 parts of an isocyanate, wherein the first foaming agent comprises a high-boiling-point alkane foaming agent and a low-boiling-point alkane foaming agent in a mass ratio of 10:7.8, wherein the high-boiling-point alkane foaming agent is cyclopentane, and the low-boiling-point alkane foaming agent comprises isopentane and propylene in a mass ratio of 5:2;

[0065] In parts by weight, the composite polyether includes 40 parts of polyether polyol, 30 parts of polyester polyol, 30 parts of polymer polyol, 5 parts of catalyst, 1.5 parts of foam stabilizer, 20 parts of flame retardant, 17.5 parts of second foaming agent and 2 parts of water; wherein the polymer polyol is POP36 / 28, the polyether polyol is Puranol RF4110A, the polyester polyol is an aromatic polyester polyol, the catalyst is POLYACAT 303, the foam stabilizer is M-6688LV, the flame retardant is TCPP, and the second foaming agent includes HFC-245fa.

[0066] Example 2

[0067] A foaming material, compared with Example 1, the difference is that the parts of the combined polyether, the first foaming agent and the isocyanate are different;

[0068] In this embodiment 2, the foaming material includes 80 parts of the combined polyether, 12 parts of the first foaming agent and 130 parts of the isocyanate, based on parts by weight.

[0069] Example 3

[0070] A foaming material, compared with Example 1, the difference is that the parts of the combined polyether, the first foaming agent and the isocyanate are different;

[0071] In this embodiment 3, the foaming material includes 120 parts of the combined polyether, 20 parts of the first foaming agent and 160 parts of isocyanate, based on parts by weight.

[0072] Example 4

[0073] A foaming material, compared with Example 1, the difference is that: in the first foaming agent, the mass ratio of the high boiling point alkane foaming agent to the low boiling point alkane foaming agent is different;

[0074] In this Example 4, the mass ratio of the high boiling point alkane foaming agent to the low boiling point alkane foaming agent is 10:6.

[0075] Example 5

[0076] A foaming material, compared with Example 1, the difference is that: in the first foaming agent, the mass ratio of the high boiling point alkane foaming agent to the low boiling point alkane foaming agent is different;

[0077] In this Example 5, the mass ratio of the high boiling point alkane foaming agent to the low boiling point alkane foaming agent is 10:3.

[0078] Example 6

[0079] A foaming material, compared with Example 1, the difference is that: in the first foaming agent, the mass ratio of the high boiling point alkane foaming agent to the low boiling point alkane foaming agent is different;

[0080] In this Example 6, the mass ratio of the high boiling point alkane foaming agent to the low boiling point alkane foaming agent is 1:1.

[0081] Comparative Example 1

[0082] A foaming material, compared with Example 1, the difference is that: the first foaming agent is composed only of a high-boiling-point alkane foaming agent, and the high-boiling-point alkane foaming agent is cyclopentane.

[0083] Comparative Example 2

[0084] A foaming material, compared with Example 1, the difference is that: the first foaming agent is only composed of a low-boiling-point alkane foaming agent, and the low-boiling-point alkane foaming agent is isopentane.

[0085] Comparative Example 3

[0086] A foaming material, compared with Example 1, the difference is that: the first foaming agent is composed only of a low-boiling-point alkane foaming agent, and the low-boiling-point alkane foaming agent is propylene.

[0087] The foaming materials of Examples 1-6 and Comparative Examples 1-3 of the present application were tested, and the testing method was as follows:

[0088] (1) Free cell density (kg / m 3 ): The density of the foam prepared by foaming in a free state (without a mold), measured according to ASTM D 1622-88.

[0089] (2) Molding density (kg / m3 ): The density of the foam foamed in the mold excluding the skin, measured according to ASTM D1622-88.

[0090] (3) Compression strength (KPa): measured according to DIN 53421-06-84 using Shimadzu AGS-J (500N).

[0091] (4) Thermal conductivity (mW / m·K): Measured at an average temperature of 10°C (upper plate 2°C, lower plate 18°C) using an EKO HC-074-200 thermal conductivity meter according to ISO 12939-01 / DIN 52612. Foam samples were cut from the center of the molded part 24 hours after the foam was prepared, and the samples were measured immediately after cutting.

[0092] The test results are shown in Table 1.

[0093] Table 1

[0094]

[0095] It can be seen from Table 1 that the molding density of the foaming materials of Examples 1-6 of the present application is less than the molding density of the foaming materials of Comparative Examples 1-3. It is known that the difference between Examples 1-6 of the present application and Comparative Examples 1-3 is that the first foaming agent in Examples 1-6 of the present application uses a high-boiling point alkane foaming agent and a low-boiling point alkane foaming agent in a mass ratio of 10:(3 to 10), while the first foaming agent in the foaming materials of Comparative Examples 1-3 uses only a high-boiling point alkane foaming agent or a low-boiling point alkane foaming agent. This shows that the present application can significantly reduce the molding density of the foaming material by mixing a high-boiling point alkane foaming agent with a low-boiling point alkane foaming agent.

[0096] It can also be seen from Table 1 that when the foaming materials of Examples 1-6 of the present application and Comparative Examples 1-3 are injected into refrigerator door bodies of the same size, the mass of the foaming materials injected into the door bodies in Examples 1-6 of the present application is less than the mass of the foaming materials injected into the door bodies in Comparative Examples 1-3. This shows that the present application can significantly reduce the mass of the foaming material used in the refrigerator, thereby reducing the cost of the foaming material, and thus reducing the production cost of the refrigerator.

[0097] The foaming material and refrigeration device provided in the embodiments of the present application are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the present application. At the same time, for those skilled in the art, according to the idea of ​​the present application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present application.

Claims

1. A foaming material, characterized in that: In parts by weight, the foaming material comprises: 80 to 120 parts of a combined polyether, 12 to 20 parts of a first foaming agent, and 130 to 160 parts of an isocyanate; Wherein, the first foaming agent comprises a high boiling point alkane foaming agent and a low boiling point alkane foaming agent in a mass ratio of 10:(3-10), the high boiling point alkane foaming agent comprises cyclopentane, and the low boiling point alkane foaming agent comprises at least one of isopentane and propylene.

2. The foam material according to claim 1, characterized in that: In parts by weight, the composite polyether includes 30-50 parts of polyether polyol, 20-40 parts of polyester polyol, 20-40 parts of polymer polyol, 4-6 parts of catalyst, 1-2 parts of foam stabilizer, 15-25 parts of flame retardant, 15-20 parts of second foaming agent and 1-3 parts of water.

3. The foam material according to claim 2, characterized in that: The polymer polyol comprises at least one of POP36 / 28, HPOP40, POP93 / 28 and EP3600; and / or, The polyether polyol includes at least one of Puranol RF4110A, Puranol RF8310, Puranol RF6282, Puranol RF6482, Donol C305 and Donol 204E; and / or, The polyester polyol is an aromatic polyester polyol.

4. The foam material according to claim 3, characterized in that: The functionality of the aromatic polyester polyol is 2 to 3, the hydroxyl value of the aromatic polyester polyol is 200 KOH / g to 250 mg KOH / g, and the viscosity of the aromatic polyester polyol is 3000 mPa·s to 4500 mPa·s.

5. The foam material according to claim 2, characterized in that: The catalyst comprises at least one of POLYACAT 303, POLYACAT 8, Dabco BX405, K15, POLYCAT 41 and DABCOT; and / or, The foam stabilizer comprises at least one of M-6688LV, M-6680 and AK-8860; and / or, The flame retardant comprises at least one of TCPP, TEP and TCEP; and / or, The second blowing agent includes HFC-245fa.

6. The foaming material according to any one of claims 1 to 5, characterized in that: The isocyanate includes polymethylene polyphenyl isocyanate.

7. The foam material according to claim 6, characterized in that: The viscosity of the polymethylene polyphenyl isocyanate is 180 mPa·s to 220 mPa·s, and the isocyanate content of the polymethylene polyphenyl isocyanate is 30 wt % to 32.2 wt %.

8. A refrigeration device, characterized in that: It comprises a heat-insulating layer, wherein the heat-insulating layer comprises the foaming material according to any one of claims 1 to 7.

9. The refrigeration device according to claim 8, characterized in that: The refrigeration device comprises a box body, and the box body comprises a shell and a box liner. The box liner is arranged on the inner side of the shell, and the heat insulation layer is arranged between the shell and the box liner.

10. The refrigeration device according to claim 8, characterized in that: The refrigeration device comprises a door body, and the door body comprises a door panel and a door liner which are arranged at intervals, and the heat-insulating layer is arranged between the door panel and the door liner.

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