JP2002205351A - Dew condensation-proof sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lightweight and compact dew condensation-proof sheet with such advantages that a great deal of electric power can be saved and surface dew condensation outside a chest can be prevented from occurring. SOLUTION: This dew condensation-proof sheet is a laminate of a composite structure comprising a surface layer, a heat shield layer and a back layer. In addition, the sheet is characterized in that the surface layer is constituted of a sheet-like material and the back layer of an air-permeable sheet-like material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dew-prevention sheet for food display in supermarkets and the like.

[0002]

2. Description of the Related Art Refrigerators / refrigerators for food display in supermarkets and the like are open during the day without any lids or covers so that shoppers can easily pick up products. When the store is closed, it is covered with a hard plastic film sheet in which specific holes are opened at equal intervals in order to prevent cold air from leaking from the inside of the refrigerator and save power. Since such a cover is housed in a roll curtain system, it is easy to draw out and rewind the cover, and it is excellent in space saving.However, due to the holes for preventing dew condensation during use, air inside and outside of the refrigerator is blocked. It was not perfect, and the effect of power saving, the purpose of using the cover, was not sufficient. In addition, despite the fact that many holes are made, the actual situation is that it is not possible to suppress the condensation itself, and there has been a problem such as a product of dew condensation water falling on the floor.

[0003] As means for solving these problems, Japanese Patent Application Laid-Open No. H11-183023 proposes a cover sheet for a frozen / refrigerated showcase in which a metal layer is laminated on one side. This cover, compared with the film sheet cover, is recognized as having an effect on power saving and prevention of dew condensation on the inside of the refrigerator, but particularly when the temperature difference between the inside and the outside of the refrigerator is large, such as a freezer, the cover is formed on the outer surface of the refrigerator. There was a problem that dew condensation occurred and the dew water dropped on the floor.

[0004]

SUMMARY OF THE INVENTION In view of the background of the prior art, an object of the present invention is to provide a lightweight and compact dew condensation preventing sheet which has high power saving, prevents surface dew condensation on the outside of the refrigerator, and is lightweight. Things.

[0005]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the dew condensation preventing sheet of the present invention is a laminate having a composite structure including a surface layer, a heat shield layer, and a back surface layer, wherein the front surface layer is a sheet material, and the back layer is a sheet material having air permeability. It is characterized by comprising.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been made to thoroughly study the above-mentioned problem, that is, a lightweight and compact dew-prevention sheet which has high electric power and prevents surface dew condensation on the outside of the refrigerator, and has a surface layer and a heat shielding layer. When a specific sheet-shaped material having a composite structure composed of a back surface layer was produced, it was found that such a problem could be solved at once.

[0007] That is, in order to prevent dew condensation and enhance power saving, a laminate having a composite structure composed of a surface layer, a heat shield layer, and a back surface phase is used. In addition, it is essential that the back layer is formed of a sheet-like material having air permeability. In the laminated sheet having such a composite structure, it is preferable that the back surface layer is disposed on the inner side surface of the storage and used in order to enhance power saving and prevent dew condensation from occurring.

In order to prevent dew condensation and enhance power saving of the laminated sheet having a composite structure of the present invention, cloth is preferably used as a sheet having air permeability constituting the back surface layer. .

That is, the dew condensation preventing sheet of the present invention has the dew condensation preventing property described later, that is, the temperature and humidity in the room outside the refrigerator or freezer are 25 ° C. and 60 ° C.
% RH, and the amount of dew condensation when the temperature and humidity in the refrigerator or freezer are measured at −25 ° C., 10% RH, and in a state of blowing cold air based on the method described in the text. Is less than or equal to 1 g / m ² · hr. For example, the temperature difference between the inside and outside of the refrigerator is 0 to 50 ° C., the humidity difference is 0 to 70%, and the amount of dew condensation is 1
g / m ² · hr or less.

[0010] In order to impart such dew condensation preventing properties, the air permeability of a sheet-shaped material measured according to JIS L1096 is 0.6 to 100 [cc / cm ² /].
[sec] is preferably used. If the air permeability is less than 0.6 [cc / cm ² / sec], a temperature difference occurs between the front surface and the back surface of the fabric to cause dew condensation. If the air permeability exceeds 100 [cc / cm ² / sec], the anti-condensation property deteriorates.

The air permeability is 0.6 to 100 [cc / c].
m ² / sec] is not particularly limited as long as it has air permeability from the entire surface, such as a woven fabric, a knitted fabric, and a nonwoven fabric, and any fabric can be used. Among them, a fiber fabric such as a woven fabric or a knitted fabric having a high tear strength is preferable. Further, as a material constituting such a fabric, a synthetic resin such as polyester, polypropylene, polyamide, polyvinyl chloride, acrylonitrile, polychlor, and polyethylene, and synthetic fibers and cotton, and natural fibers such as wool can be formed alone or in combination. A polyamide having high strength is preferable.

In order to enhance power saving and prevent dew condensation from occurring, the heat shielding layer has a heat conductivity of 30 [mW /
m · K] or less. When the thermal conductivity is 30 [mW / m · K] or less, there is a heat blocking effect, and dew condensation can be prevented.
However, when it exceeds 30 [mW / m · K], there is no heat blocking effect, and dew condensation occurs. In order to make the heat conductivity 30 [mW / m · K] or less, a configuration in which an air layer is provided between the front surface layer and the back surface layer is preferably adopted. That is, an air layer exists between the surface layer and the back layer. The thickness of the air layer is preferably 0.7 cm to 10 cm. 0.7
When the diameter is less than cm, there is no heat insulating property and dew condensation occurs. If it is 10 cm or more, compactness is lost, and it is difficult to install in a refrigerator or freezer. The heat shielding layer may include an air layer, and for example, a fibrous structure or a corrugated structure containing a large amount of air, such as a woven fabric, a knitted fabric, or a nonwoven fabric, is preferably employed. Such an air layer can also be provided by making the respective surfaces of the fabric of the back layer and the sheet-like material of the front layer uneven, and the air amount can be increased by increasing the degree of the unevenness. In addition, it can be provided by installing a spacer. In this case, the air amount can be increased by increasing the thickness of the spacer. The thermal conductivity was measured according to JIS A
It was determined by 1412-2.

As the sheet constituting the surface layer of the laminated sheet having a composite structure of the present invention, a laminated sheet containing a metal layer in at least one selected from a fabric and a film is preferably used. Here, any material having a sheet form such as a film, a woven fabric, a knitted fabric, or a nonwoven fabric can be used without any particular limitation. However, a woven fabric or a knitted fabric having a high tear strength is preferably used.
The materials include polyester, polypropylene, polyamide, polyvinyl chloride, acrylonitrile,
Although synthetic resins such as polyclar and polyethylene and natural fibers such as synthetic fibers and cotton and wool can be used alone or in combination, polyesters having low hygroscopicity and excellent dimensional stability are preferred.

The metal layer laminated on at least one selected from the cloth and the film is not particularly limited as long as it has heat ray reflectivity, and may be a metal such as gold, silver, copper, aluminum or stainless steel. Although simple substances and alloys can be used, aluminum which is relatively inexpensive and has good moldability is preferably used. Also, the form is evaporation,
It is not particularly limited, such as a foil or a plate shape, but is preferably flexible since it is stored in a roll curtain system, and is preferably a vapor-deposited or foil-shaped.

The metal layer is preferably provided on the outermost layer of the laminated sheet in order to make maximum use of the heat ray reflectivity of the metal. Further, it is preferable to use the metal layer surface inside the refrigerator because it reflects the heat rays in the refrigerator and is effective for the cool keeping effect, and the power consumption of the refrigerator / freezer is reduced. Further, since the amount of heat transfer to the outer surface of the refrigerator becomes smaller, the effect of lowering the surface temperature of the outer surface of the refrigerator becomes smaller, and the occurrence of dew condensation can be prevented.

Further, when the metal layer is provided on the outermost layer of the laminate, as described above, it is possible to obtain a heat retaining effect, a power saving property, and a dew condensation preventing property. The metal layer is oxidized and the heat ray reflectivity decreases. In such a case, by further installing a transparent resin thin film coating layer on the metal layer, oxidation can be prevented, and a heat retaining effect,
It is preferable because power saving property and dew condensation preventing property can be obtained.

As the resin thin film transparent coating layer here,
There is no particular limitation on general synthetic resins such as acryl, urethane, fluorine, polyester, and silicone. It is important that the thickness of the resin thin film transparent coating layer does not hinder the heat ray reflectivity of the metal layer, and is preferably 1 μm or less, and more preferably 500 Å or less. Such a resin thin film transparent coating layer is preferably a transparent film, since the color impairs the heat ray reflectivity of aluminum.

The thickness of the sheet-like material constituting the surface layer is 1 mm since it is stored in a roll curtain system.
Or less, more preferably 500 μm or less.

The dew-condensation-preventing property referred to herein means that the temperature difference between the inside and outside of the refrigerator or freezer is 0 to 50 ° C., the humidity difference between the inside and outside of the refrigerator is 0 to 70% RH, and the condition of dew condensation is blown by an air curtain. It means that the amount is 1 g / m ² · hr or less. Specifically, it is measured by the following measurement method.

That is, the temperature difference and humidity difference between the inside and outside of the refrigerator or freezer (Medical Freezer manufactured by Sanyo Electric Co., Ltd.) were measured at room temperature of 25 ° C., 60% RH, -25 ° C.
Installed so as to be 10% RH and keep it constant. In addition, a fan is installed in the refrigerator or freezer so that the cool air hits the upper part. With the upper door of the refrigerator or freezer opened, the dew condensation preventing sheet is attached as a cover so as to cover the opening, and 12 hours later,
The amount of water droplets adhering to the cover surface is measured and defined as the amount of dew condensation. However, the unit is converted to g / m ² · hr.

The prevention of dew condensation referred to here means that the temperature difference between the inside and outside of the refrigerator is zero.
-50 ° C, 0-70% humidity difference between the inside and outside of the refrigerator, and means that the amount of dew condensation is 1 g / m ² · hr or less under the condition of blowing cold air with an air curtain. Is measured by

Further, it is preferable to apply a fungicide / antibacterial treatment so that mold does not grow on the cloth. The fungicide / antibacterial agent is not particularly limited, but a metal salt of an organic acid or an inorganic silver is preferred. These antifungal and antibacterial agents are applied to the fabric by bath treatment or coating.

[0023]

Next, the present invention will be described in more detail by way of examples.

Various evaluations in the examples were performed according to the following methods.

Air permeability: JIS L1096 (8.
27.1A method).

The air permeability was measured on the fabric before lamination.

Dew condensation: Temperature difference and humidity difference between inside and outside of the room are 25 ° C, 60% RH in the room, -25 ° C in the room, 10%
The freezer / refrigerator (Medical Freezer manufactured by Sanyo Electric Co., Ltd.) is kept constant so as to obtain RH. Attach a fan inside the freezer / refrigerator so that cool air hits the upper part. With the upper door of the refrigerator / freezer opened, the cover is attached so as to cover the opening, and after 12 hours, the amount of water droplets adhering to the surface is measured. However, the unit is converted to g / m ² · hr.

Example 1 The back layer had a total fineness of 470 dtex, 72 filaments, a strength of 8.8 g / decite, and an elongation of 23.0.
% Of nylon 6.6 fiber filament yarn and a warp yarn and weft yarn density of 36 / 2.54 cm. The air layer was 8 cm as a heat shield layer. The surface layer was a polyester film having a thickness of 50 μm, and a dew condensation preventing sheet in which these three layers were laminated in the order of a surface layer, a heat shield layer, and a back layer was obtained. The air layer was formed by providing a spacer having a thickness of 8 cm above and below the surface layer and the back layer of the dew condensation preventing sheet. The rear surface layer of the dew condensation prevention sheet is disposed on the inner side surface of the refrigerator.

Example 2 An aluminum-evaporated polyester film obtained by evaporating aluminum to a thickness of 600 Å on a 50 μm-thick polyester film, a total fineness of 56 dtex,
A polyester multifilament having 24 single yarns was obtained by using a warp yarn density of 60 yarns / 2.54 cm and a weft yarn density of 50 yarns / 2.
A plain fabric having a size of 54 cm was bonded and laminated so that the aluminum-deposited surface was the outermost layer on the inside of the refrigerator. The air layer was 5 cm as a heat shield layer. The back layer is made of nylon 6.6 filament yarn having a total fineness of 470 dtex, 72 filaments, a strength of 8.8 g / decitex, and an elongation of 23.0%, and a warp yarn and a weft yarn density of 36.
This was a plain woven fabric having a size of 2.54 cm. These three layers were laminated in the order of a surface layer, a heat shield layer, and a back surface layer to obtain a dew condensation preventing sheet. The air layer was formed by providing a spacer having a thickness of 5 cm on upper and lower portions of the surface layer and the back surface layer of the dew condensation preventing sheet. The rear surface layer of the dew condensation prevention sheet is disposed on the inner side surface of the refrigerator.

Comparative Example 1 A roll curtain type dew-prevention sheet was obtained by coating a soft polyurethane material having moisture permeability on one surface of a cloth with a knife coater.

Comparative Example 2 A roll curtain type dew-prevention sheet having specific holes formed at regular intervals in a hard plastic film was obtained.

The anti-condensation sheets obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were placed indoors at 25 ° C., 60% RH, and
The measurement was carried out under the conditions of 25 ° C. and 10% RH by the above-described method for measuring the amount of dew. The power consumption during that time was measured with a wattmeter. Table 1 shows the results.

[0033]

[Table 1]

It can be seen that the dew-prevention sheets of Examples 1 and 2 did not cause any dew condensation on the inner and outer surfaces of the sheets as compared with those of Comparative Examples 1 and 2. It can also be seen that the amount of power is small and the power saving is excellent.

[0035]

According to the present invention, it is possible to provide a dew condensation preventing sheet which has a high power saving effect, prevents dew condensation on the surface, and is lightweight and compact, and in particular, prevents dew condensation on the outer surface of the refrigerator.

 ──────────────────────────────────────────────────続 き Continued on front page F term (reference) 3L102 JA04 KA01 MA03 MB20 4F100 AB01A AB10A AK01A AK41 AK48 AR00A AR00C BA03 BA05 BA07 BA10A BA10C DD21D DD21E DG11A DG11C GB48 JD02C JJ02B JL07 JN01YYY00B

Claims (11)

[Claims] 1. A laminate having a composite structure consisting of a surface layer, a heat shield layer and a back surface layer, wherein the surface layer is a sheet material and the back layer is a breathable sheet material. An anti-condensation sheet, characterized in that: 2. The air-permeable sheet material constituting the back layer has an air permeability of 0.6 to 100 [cc / cm ^2, measured according to JIS L1096 8.27.1A method.
/ Sec], the dew condensation preventing sheet according to claim 1. 3. The heat shield layer according to claim 1, wherein said heat shield layer has a thermal conductivity of 30 [mW / m · K] or less.
Or the dew condensation preventing sheet according to 2. 4. The dew condensation prevention according to claim 1, wherein said heat shielding layer is formed by providing an air layer between said front surface layer and said back surface layer. Sheet. 5. The sheet according to claim 1, wherein the sheet-like material constituting the surface layer is a laminated sheet containing a metal layer in at least one selected from a fabric and a film. Condensation prevention sheet. 6. The dew condensation preventing sheet according to claim 5, wherein said metal layer is disposed on an outermost layer of said laminated sheet. 7. The dew condensation preventing sheet according to claim 5, wherein said metal layer is provided with a resin thin film transparent coating layer thereon. 8. The dew condensation preventing sheet according to claim 5, wherein said metal layer is aluminum. 9. The sheet according to claim 5, wherein the thickness of the laminate is 1 mm or less. 10. The sheet according to claim 1, wherein the sheet is used as a cover for a refrigerator or a freezer. 11. The dew condensation preventing sheet has a temperature and humidity in a room outside a refrigerator or a freezer of 25 ° C. and 60% RH.
The temperature or humidity in the refrigerator or freezer is -25 ° C, 1
The amount of dew condensation measured at 0% RH under the condition of blowing cold air based on the method described in the text is 1 g / m2.
The condensation prevention sheet according to any one of claims 1 to 10, wherein the sheet has a viscosity of ² hr or less.