JPS6342859Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heat-retaining case that has better heat-retaining properties, consumes less electricity, is inexpensive, and has a transparent window compared to conventional products.

Insulating cases that are used to sell warm side dishes, steamed buns, and other foods at supermarkets or stores have been designed with openings on one to four sides to improve the visibility of the products mentioned above. They are made of extremely large pieces of transparent glass, and to increase heat retention, double or triple glazing is usually used with an air layer in between.

However, even when double glazing is used, the heat insulation effect is not sufficient, and there are drawbacks such as the fact that food that has been heated may become cold, especially in winter, and the amount of electricity used increases.

The present invention relates to an improvement of a heat-retaining case that has such drawbacks. The purpose of the present invention is to use a heat-reflecting transparent laminate mainly made of a plastic film laminated with a metal thin film and a metal oxide thin film on top of the plastic film as a heat-insulating sheet, to produce a heat-retaining showcase with a transparent window. This is achieved by bonding it to the transparent window.

According to the method of the present invention, an effect equivalent to that of triple glazing can be obtained by bonding to conventional double glazing. For example, the heat transmission coefficient K of double glass is 2.8 ~
3.5Kcal/m ²・hr・℃, but by bonding to double glass according to the present invention, K can be reduced to 1.7~
2.7Kcal/m ²・hr・℃, which is the K of triple glass.
(1.7-2.0Kcal/m ²・hr・℃). In addition, thermal display cases are prone to condensation, and the condensation clouds the transparent glass part, making it difficult to see through the products inside. However, with this method, when the bonding position is as shown in Figure 6 below, dew condensation on double-glazed glass occurs at an outside temperature of 31°C or lower.
Condensation only occurs below ℃, and this is as effective as condensation on triple-glazed glass.

The above is just one example, but according to the present invention, the heat retention of conventional thermal insulation cases can be significantly improved, the amount of electricity saved is large, the condensation resistance is increased, and the heating device for thermal insulation cases can be made smaller. and
Therefore, the entire display case becomes compact, and it is possible to manufacture the display case at low cost.

In the present invention, metals and metal oxides (hereinafter,
The metal layer (abbreviated as "metal layer") is one or more metals selected from the group consisting of gold, silver, copper, palladium and aluminum, and metal oxides such as _In2O3 , _SnO2 , CdZnO4 _, etc., and is formed to a thickness of _50-400 Å on an undercoat layer of 3μ or less made of, for example, a silicon- or titanium-based organometallic compound, which is formed directly on or on the surface of a transparent plastic film, and on a high refractive index dielectric layer (hereinafter abbreviated as "dielectric layer"), which is further formed on the surface of the undercoat layer. By forming a metal oxide thin film on a metal thin film in this way, it functions in the same way as the dielectric layer, which will be described later, and transparency is improved. The metal layer is formed to a thickness of 50-400 Å on an undercoat layer of 3μ or less made of, for example, a silicon- or titanium-based organometallic compound, which is formed directly on or on the surface of the transparent plastic film, and on a high refractive index dielectric layer (hereinafter abbreviated as "dielectric layer"), which will be described later. By forming a metal oxide thin film on a metal thin film in this way, it functions in the same way as the dielectric layer, which will be described later, and transparency is improved. The metal layer is formed to a thickness of 50-400 Å on an undercoat layer of 3μ or less made of, for example, a silicon- or titanium-based organometallic compound, which is further formed on the surface of the undercoat layer.
_Ti2O3 , _TiO2 , and its hydrates), bismuth oxide, zinc sulfide, tin oxide, indium oxide, etc. _, with a film thickness of 50 to
Although a structure sandwiching the metal oxide layer between dielectric layers of 600 Å is acceptable, this is not necessarily required in the present invention in which a metal oxide layer is formed. In addition, in order to improve the mechanical strength of the metal oxide layer or the dielectric layer, it is possible to protect the metal oxide layer or the dielectric layer with an organic or inorganic protective layer such as an acrylic resin, polyester resin, or silicone resin, and further a transparent heat insulating layer may be laminated.

The transparent plastic film that serves as the support on which the film is formed includes, for example, resins such as polyethylene terephthalate, polyethylene-2,6-naphthalate, and polybutylene terephthalate, polyolefin resins such as polyketone, polyethylene, and polypropylene, and polyvinyl chloride. ,
Polyamide resins such as polysulfone polyphenylene oxide, polymethyl methacrylate, and polystyrene, and films or sheets of cellulose resins such as cellophane and cellulose triacetate are used.

The present invention uses a heat-reflecting transparent laminate mainly made of a plastic film laminated with metal thin films and metal oxide thin films as a heat-insulating sheet, and is made of transparent glass with extremely large openings, as shown in FIGS. bonded to the transparent glass surface of the thermal insulation case.

Insulation cases are usually available in horizontal and vertical types.
Any of these may be used, but it is particularly effective in the case of a vertical type. This is because the temperature distribution in the longitudinal direction inside the heat retaining case is relatively uniform, making it particularly difficult to resist condensation, and the method of the present invention is effective.

The bonding is as shown in FIGS. 5 to 7, for example, and these are examples of bonding to double-glazed glass, but it is also possible to bond to triple-glazed or higher glass in the same way.
In particular, it is preferable to bond on the inner surface of the glass as shown in FIGS. 6 and 7, for example.

Of course, the effect will be further improved if the heat shielding film is bonded to two or more glass surfaces.

The bonding method may be to bond the plastic film of the heat shielding sheet to the glass, or to bond the heat ray reflective transparent laminate to the glass.

Bonding can be performed using a conventionally known method, such as an adhesive or a pressure-sensitive adhesive.

These heat insulating sheets can be applied to existing use cases as well as newly manufactured use cases.

[Brief explanation of the drawing]

Figures 1 to 4 are examples of thermal insulation cases.
Figures 1 and 3 show cross-sectional views, and Figures 2 and 4 show the external appearance. Further, FIGS. 5 to 7 show examples in which a heat-insulating sheet is bonded to the transparent double-glazed glass portion of a heat-retaining show case. In addition, 1 indicates transparent glass, 2 indicates a heat-insulating sheet, A indicates the outside of the heat-insulating display case, and B indicates the inside of the heat-insulating display case.

Claims (1)

[Scope of utility model registration request] A heat-reflecting transparent laminate mainly consisting of a plastic film on which a metal thin film and a metal oxide thin film are laminated is bonded as a heat shielding sheet to the transparent window portion of a heat-retaining show case having a transparent window. Also, a case for keeping warm.