JPH08280511A - Heat retaining dish - Google Patents

Abstract

PURPOSE: To provide a heat retaining dish preventing its wall having a double- wall structure from being swollen, by welding or sticking the edge where an inner member and an outer member are kept in contact with each other, and storing a moisture absorbent in a hollow chamber formed between both members. CONSTITUTION: The connection section between an inner member 2 having the inner shape of a dish main body 1 and an outer member 3 having the outer shape is welded, and a hollow chamber 5 is formed inside. A moisture absorbent 6 is stored on the bottom face of the hollow chamber 5, and a heat insulating material 7 is filled in the portion other than the moisture absorbent 6 of the hollow chamber 5. The connection section 4 may be stuck. The outer member 3 and inner member 2 are formed out of a thermoplastic resin as raw material by injection molding, vacuum molding, or hollow chamber molding. A foam body made of continuous foam or independent foam, e.g. polyurethane, is used for the heat insulating material 7. A material capable of controlling the steam pressure and having moisture absorbing force can be used for the moisture absorbent 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic heat-insulating tableware used for meals in hospitals and the like.

[0002]

2. Description of the Related Art Conventionally, a tableware for warming, which is composed of a plastic tableware main body and a lid thereof used for lunch in hospitals, etc., is not only provided with a lid for keeping foods placed on the tableware warm. For the purpose of enhancing the heat retention effect, the lid of the tableware and / or the tableware main body has a double-wall structure formed of an inner shell member and an outer shell member, and both edges are abutted by welding or adhering the members. It is often practiced to form a hollow chamber between them. Regarding the plastic heat-insulating tableware having the hollow chamber, in order to further enhance the heat-retaining effect, elimination of air in the hollow chamber and / or filling of the hollow chamber with a heat insulating material is performed as a conventional means.

[0003]

Generally, after eating tableware for meals in hospitals and the like is eaten by consumers, it is repeatedly washed with washing water and heated and dried for sterilization / disinfection, and reused. The same applies to heat-insulating tableware.

A double-walled structure is formed by an inner shell member and an outer shell member, and the two members are welded or adhered to each other at their abutting edges to form a hollow chamber between them. When the plastic heat-insulating tableware is subjected to the usual use as described above and the washing with the washing water is repeated many times, the water is gradually permeated and stored in the hollow chamber. When the hollow chamber is filled with a hygroscopic heat insulating material such as polyurethane mat, the penetration of water into the hollow chamber is further promoted, and the hollow chamber is filled with a hygroscopic heat insulating material. In the heat-retaining tableware, the moisture in the ambient air is gradually absorbed and accumulated in the hygroscopic heat insulating material in the hollow chamber even during storage in a normal indoor environment.

On the other hand, heating and drying of plastic tableware after washing is carried out in a tableware storage, and the temperature is controlled at 100 ° C or lower, and is usually maintained in the temperature range of 70 to 90 ° C. Here, regarding the double-walled plastic heat-insulating tableware having water accumulated in the hollow chamber, when this is heated and dried in the tableware storage, since the hollow chamber is in a closed state, the hollow space is formed by vaporization and expansion of water. The internal pressure of the room rises, the inner shell side and / or outer shell side walls of the double-wall structure of the heat-insulating tableware swells convexly, and the appearance of the tableware is significantly impaired, and the tableware function is lost. There was a problem that it would not be achieved.

Conventionally, as a method for dealing with this problem,
The double-walled wall of the heat-insulating tableware, that is, the inner shell side and / or
Or increase the mechanical strength by increasing the thickness of the outer shell side wall,
It was designed to withstand an increase in the internal pressure of the hollow chamber, but if the wall thickness is increased, the weight of the heat-retaining tableware becomes heavier, making it difficult to perform various tasks during lunch, and the sense of use of the eating person is also increased. There was a problem that it was not desirable.

The bulging of the double-walled wall of the heat-insulating tableware is not limited to vaporization and expansion due to the heating of the water that has penetrated into the hollow chamber surrounded by the inner and outer double walls of the heat-insulating tableware, and It is also generated by the heat expansion of the trapped air. Therefore, in order to prevent the heat-insulating tableware from expanding due to the heat-expansion of the air, the lid of the heat-insulating tableware and / or the tableware main body is provided with an inner shell member and an outer shell member. With a double-wall structure formed by, when welding or bonding the edges where both members abut,
The device should be devised so that the air in the hollow chamber formed by the double wall structure wall is removed, and this is described in, for example, Japanese Patent Publication No. 14566/1992.

An object of the present invention is to provide a tableware for heat insulation that prevents the wall of a double wall structure from bulging.

[0009]

According to the present invention, in a double-walled tableware formed of an inner shell member having an inner surface shape and an outer shell member having an outer surface shape, both members abut. A hygroscopic agent is contained in a hollow chamber formed between the members by welding or adhering the edges.

As the hygroscopic agent, a material capable of controlling the vapor pressure of water vapor is used.

The above-mentioned inner and outer shell members are welded by ultrasonic welding, spin welding, high-frequency induction heating welding, or the like.

A heat insulating material is filled in the hollow chamber.

The tableware for heat insulation is composed of a tableware body.

The tableware for heat retention comprises a tableware body and a lid thereof.

[0015]

In the heat-retaining tableware constructed as described above, even if water is dried in a state where water is accumulated in the hollow chamber, vaporization of water is suppressed by the hygroscopic agent stored in the hollow chamber, and the internal pressure of the hollow chamber is reduced. The rise is suppressed small. Therefore, the bulging of the wall of the double wall structure is prevented.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, the tableware for heat retention is composed of a tableware body and a lid, which are generally designated by reference numerals 1 and 1A, respectively.

In the tableware body 1, a joint 4 between an inner shell member 2 having an inner surface shape and an outer shell member 3 having an outer surface shape is welded, and a hollow chamber 5 is defined inside. . A hygroscopic agent 6 is stored on the bottom surface of the hollow chamber 5, and a portion of the hollow chamber 5 other than the hygroscopic agent 6 is filled with a heat insulating material 7. However, the joint portion 4 may be adhered. The outer shell member 3 and the inner shell member 2 are manufactured using a thermoplastic resin as a raw material by an injection molding method, a vacuum molding method, a hollow chamber molding method, or the like. The thermoplastic resin is not particularly limited, but includes polyethylene, polypropylene and other polyolefins, acrylonitrile-butadiene-styrene copolymer resin, polycarbonate, polyamide, saturated polyester, polyacetal, polyphenylene ether, polyetherimide, polysulfone, and mixtures thereof. (Including a polymer alloy) may be exemplified. Of these, polypropylene, polycarbonate, polysulfone and the like are most preferable in consideration of the easiness of welding work and the usability of tableware for heat insulation. Further, both members may be preheated to 50 to 120 ° C. and welded prior to welding.

As the heat insulating material 7, an open cell or closed cell such as polyurethane or polystyrene is used. It is essential that these bubbles are heated to a high temperature, specifically 50 ° C. or higher, preferably 80 to 150 ° C., before welding or bonding the joint portions 4 of the inner and outer shell members 2 and 3. If the temperature is 50 ° C. or lower, the effect of reducing the pressure inside the hollow chamber 5 is small when the temperature inside the hollow chamber 5 returns to room temperature. Conversely 1
When heated to 50 ° C or higher, the heat insulating material 7 and the inner and outer shell members 2, 3
It is not preferable because it causes the heat deterioration of.

The inner and outer shell members 2 and 3 are welded by ultrasonic welding, spin welding, vibration welding, high frequency induction heating welding, or the like. In addition, depending on the material of both members 2 and 3, they may be bonded using an adhesive.

The hygroscopic agent 6 is a material capable of controlling the vapor pressure of water vapor, and is not particularly limited as long as it has a hygroscopic power (water holding capacity, holding capacity), but a material having a large hygroscopic power, such as calcium chloride or chloride. Magnesium, silica gel, synthetic zeolite and the like are preferable, and sodium acetate, potassium acetate, potassium nitrate, sodium bromide, potassium chloride, sodium chlorate, ammonium sulfate and the like are also effective.
The storage amount of the hygroscopic agent 6 is determined in consideration of the amount of water accumulated in the hollow chamber 5 and the hygroscopic force, but is usually 0.05 to 10 grams, preferably 0.1 to 5 grams. Is. The storage of the hygroscopic agent 6 in the hollow chamber 5 is performed by a simple method of placing the hygroscopic agent 6 on the center of the inner surface of the outer shell member 3 of the hollow chamber 5 before welding both shell members 2 and 3.

On the other hand, the lid 1A has substantially the same configuration, and the reference numeral is appended with the subscript A to omit duplicated description.

[0023]

[Experimental Example 1] A heat insulation sheet made of expanded polypropylene and 1.5 g of powdered calcium chloride preformed in conformity with the shape of the hollow chamber 5 were placed in the hollow of the tableware body 1, and the whole was placed in an air thermostat at 130 ° C. After heating for 30 minutes, it is taken out and quickly mounted on a vibration welding machine, and the joint portion 4 of the inner shell member 2 and the outer shell member 3 is fitted and vibration welding is performed.

The tableware body 1 thus formed was immersed in boiling water for 50 hours, placed in a constant temperature dryer at 120 ° C. for 1 hour, then taken out and allowed to cool, and the degree of swelling was measured, but there was no change.

On the other hand, a tableware body molded in the same manner as in Experimental Example 1 was tested in the same manner as in Experimental Example 1 except that the powdery calcium chloride was not placed in the hollow chamber. As a result, the inner bottom portion of the tableware body was swollen, and the maximum movement distance of the inner shell member was 17 mm.

[0026]

[Experimental Example 2] In the molding of heat-insulating tableware, the tableware body 1 was molded in the same manner as in Experimental Example 1 except that the foamed polypropylene insulation sheet was replaced with a foamed polyurethane insulation sheet. The test was conducted, but there was no swelling.

On the other hand, a tableware body molded in the same manner as in Experimental Example 2 except that the powdered calcium chloride was not placed in the hollow chamber was tested in the same manner as in Experimental Example 1. As a result, the inner bottom of the tableware was swollen, and the maximum movement distance of the inner shell member was 14.5 mm.

[0028]

[Experimental Example 3] In the molding of heat-retaining tableware, Experimental Example 1
Put the tableware body 1 molded in the same manner as in 1 above into a steam bath at 80 ° C for 8 hours, then take it out and keep it in a constant temperature dryer at 60 ° C for 16 hours as one cycle. After repeating this cycle 30 times, 120 ° C It was put in a constant temperature dryer and kept for 1 hour, then taken out and allowed to cool, and the degree of swelling was measured, but there was no change.

On the other hand, after molding in the same manner as in Experimental Example 1 except that the powdered calcium chloride was not put in the hollow chamber,
The test was conducted in the same manner as in Experimental Example 3. As a result, the inner bottom of the tableware bulged, but the maximum movement distance of the inner shell member was 2 mm.
Met.

[0030]

[Experimental Example 4] Experimental example 2 was used for forming the tableware for heat retention.
The tableware body 1 molded in the same manner as in 1. was tested in the same manner as in Experimental Example 3. As a result, the swelling of the inner bottom portion of the tableware body 1 was 1 mm or less with respect to the maximum movement distance of the inner shell member 2.

On the other hand, a tableware body molded in the same manner as in Experimental Example 2 except that the powdery calcium chloride was not placed in the hollow chamber was tested in the same manner as in Experimental Example 3. As a result, the inner bottom of the tableware was swollen, and the maximum movement distance of the inner shell member was 9.5 mm.

[0032]

As described above, according to the present invention, the following excellent effects are exhibited. (1) By storing a hygroscopic agent in the hollow chamber, even if it is heated and dried with water accumulated in the closed hollow chamber,
Since the vaporization of water is suppressed and the rise of the internal pressure in the hollow chamber is reduced, it is possible to prevent the inner shell side and / or the outer shell side wall of the double-wall structure of the tableware for heat retention from bulging in a convex shape.

(2) As a method for dealing with the problem that the inner wall and / or the outer wall of the double wall structure of the tableware for heat retention bulges in a convex shape, the double wall of the tableware for heat retention has hitherto been known. The wall of the structure, that is, the wall on the inner shell side and / or the outer shell side is made thicker to increase the mechanical strength so as to withstand the increase in the internal pressure of the hollow chamber. No need. As a result, if the wall is made thicker, the weight of the tableware for heat retention becomes heavier, which makes it difficult to carry out various tasks during lunch, and there is no problem that the eating sensation of the eating person becomes unpleasant. Further, the material cost can be reduced by reducing the wall thickness.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tableware main body 1A ... Lid 2, 2A ... Inner shell member 3, 3A ... Outer shell member 4, 4A ... Joint part 5, 5A ... Hollow chamber 6, 6A. ..Hygroscopic agents 7, 7A ... Insulation materials

Claims (6)

[Claims] 1. A double-walled tableware formed of an inner shell member having an inner surface shape and an outer shell member having an outer surface shape, wherein both edges are welded or bonded to each other. A tableware for heat retention, characterized in that a hygroscopic agent is housed in a hollow chamber formed between members. 2. The tableware for heat retention according to claim 1, wherein a material capable of controlling the vapor pressure of water vapor is used as the hygroscopic agent. 3. The inner and outer shell members are welded by ultrasonic welding,
The tableware for heat retention according to claim 1, which is performed by spin welding, high frequency induction heating welding, or the like. 4. The tableware for heat retention according to claim 1, wherein the hollow chamber is filled with a heat insulating material. 5. The tableware for heat insulation according to claim 1, wherein the tableware for heat insulation is composed of a tableware body. 6. The tableware for heat insulation according to claim 1, wherein the tableware for heat insulation comprises a tableware body and a lid thereof.