JP2005272214A - Insulated container and its producing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insulated container where the temperature of a contained article with high or low temperature is difficult to be changed. <P>SOLUTION: The insulated container is provided with a glazed foaming layer on the wall of a ceramic container body and is formed with a glazed protecting layer on the outer face of the glazed foaming layer. The glazed foaming layer is produced by baking a glaze comprised of a glass forming material, a foaming agent, a plasticizer and a low thermal expanding agent. A method for producing the insulated container involves steps where the glaze mixed with the foaming agent generating a gas when heated is coated on the outer face of an unglazed container, fired and formed with the glazed foaming layer on the outer face. The glass forming material may contain feldspar and the low thermal expanding agent may contain petalite. The foaming agent can be selected from silicon carbide and iron oxide. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat-insulating container in which high-temperature or low-temperature contents are contained and the temperature of the contents hardly changes.

  When a hot drink such as tea is filled in a container, there is a need to prevent the container from being cooled by heat transfer from the wall of the container. Alternatively, when a hot beverage such as tea is contained in the container, there is a demand for preventing the outer wall surface of the container from becoming too hot to hold by hand. As a countermeasure, it is conceivable that the container is made of a porcelain that is porous and has a lot of pores to improve the heat insulation, and actually disclosed (for example, see Patent Document 1). A pottery with many parts is low in strength, has a thick container wall, and has a small internal volume with respect to a certain outer shape, which may not be preferable in practical use and design.

Moreover, it is disclosed that fine hollow foam particles are baked on the surface of the substrate using a normal glaze as a binder to form a heat insulating and heat insulating layer (see, for example, Patent Document 2). In this method, fine hollow foam particles are attached to the surface of the substrate using a glaze as a binder and then baked. Fine hollow foam particles are not easy to uniformly disperse in liquid glazes, and therefore it is difficult to adhere to the surface of the substrate in a uniform layer or to a predetermined thickness, making it uniform In addition, it is difficult to obtain a fired layer having a predetermined thickness. In particular, it is extremely difficult to uniformly attach the fine hollow foam particles to the surface of the substrate in a multilayer shape. In addition, since the bakable fine hollow foam particles such as Shirasu balloons have extremely low strength, the heat insulating and heat retaining layer obtained in this manner has low strength.
JP 2002-191454 A (Claims) Japanese Utility Model Publication No. 57-150531 (Claims)

  The object of the present invention is that the contents of the contents are not easily changed because the contents of high or low temperature are contained, and even if the container is grasped by hand immediately after containing a hot beverage such as tea, it is not too hot to grasp. It is to provide an insulated container. And it is providing the heat insulation container with easy manufacture and high surface strength.

  The gist of the present invention is that the container is a heat-insulating container provided with a layer of foamed foam on at least a part of the wall surface of the ceramic container base. In addition, in this invention, when a ceramic container has an accompanying part like the case with a handle, this accessory part shall be called a ceramic container. In addition, when a ceramic container is provided with attached parts as in the case with a lid, the attached parts are referred to as a ceramic container.

  A protective soot layer may be formed on the wall surface of the foam soot layer.

The layer of foamed foam may be formed by firing a glaze mixed with a foaming agent,
The glaze is
Glass forming material 30 to 100 parts by weight The foaming agent may comprise 0.5 to 10 parts by weight.

  In the heat insulating container, the glaze may further comprise 5 to 70 parts by weight of a low thermal expansion material.

  The glaze may further comprise 1 to 15 parts by weight of a plasticizer.

  The glass former may include feldspar.

  The low thermal expansion material may include petalite.

  The blowing agent can be selected from silicon carbide and iron oxide.

In addition, the gist of the present invention is that
Preparing an unbaked container,
Preparing a glaze mixed with a foaming agent that generates gas by heating,
Attaching the glaze mixed with the foaming agent to the wall surface of the unglazed container;
It is a manufacturing method of a heat-insulating container including a firing step of firing the unglazed container to which the glaze mixed with the foaming agent is adhered and forming a foamed foam layer on the wall surface.

  The manufacturing method may further include a step of glazing on the wall surface of the formed foamed cocoon layer.

  In the manufacturing method, the glaze may contain makeup mud.

  In the said manufacturing method, the baking in the said baking process may be made at 1100-1350 degreeC.

  In the heat insulating container of the present invention, the temperature of the high-temperature or low-temperature contents contained in the container hardly changes.

  The heat insulating container of the present invention can prevent the outer wall surface of the container from becoming so hot that it is held by hand in a state where high temperature contents are contained.

  The heat-insulated container of the present invention can prevent the container from feeling too cold if the outer wall surface of the container is held by hand in a state where low-temperature contents are contained.

  The heat-insulated container of the present invention does not feel the cold touch unique to pottery when held by hand, and has a warm and relaxing touch.

  By the method for producing a heat-insulating container of the present invention, a layer of foamed rice cake having a low coefficient of thermal expansion can be formed, and the heat-insulating container of the present invention can also be applied to a container for cooking such as a clay pot.

  Embodiment of the heat insulation container of this invention is described using drawing. As shown in FIG. 1, the heat insulating container 2 of the present invention is provided with a layer 6 of foamed foam containing bubbles 7 on the outer surface of a ceramic container base 4.

  The heat-insulating container of the present invention is prepared by uncoating a molded body for ordinary ceramics to make an unglazed container, and applying a glaze mixed with a foaming agent to the outer surface of the container in a layered manner or by immersing it. The unglazed container to which the glaze has been applied and dried is preferably baked at 1100 to 1350 ° C., more preferably at 1150 to 1300 ° C., to form a decorative layer made of foamed candy on the outer surface. .

  Since the foamed soot layer 6 is excellent in heat insulation, when hot water is poured into the heat insulating container 2, the poured hot water is difficult to cool. Moreover, the temperature rise of the outer surface of the heat insulation container 2 after hot water is poured is small compared with the normal ceramic container. Therefore, it is possible to easily hold a container filled with hot water by hand. The foamed cocoon layer 6 may be formed on the entire outer surface of the ceramic container base 4, but may be formed on a predetermined part or a main part that is touched by the hand when the heat insulating container 2 is handled. Further, the foamed soot layer 6 may be formed on the inner surface of the ceramic container base 4 as in the heat insulating container 2b shown in FIG.

  Furthermore, since the layer 6 of foamed foam has a lower heat transfer coefficient when it comes into contact with an object such as a hand than a normal ceramic container, even if the surface is relatively hot, it can be handled by hand for a short time. Can have. Also, when it is left at room temperature, when the surface is lower than the body temperature, when it is touched with a finger, etc., the cold feeling felt with the fingertip when touching a normal ceramic container is hardly felt, The touch is warm.

  The foamed soot layer 6 is baked at a high temperature together with the baked base material and has a low coefficient of thermal expansion. Therefore, even if it is applied to a container for cooking using a base having a small coefficient of thermal expansion such as a clay pot to form a foamed rice cake layer, the foamed rice cake layer is unlikely to crack during use.

  Furthermore, the foamed soot layer 6 has air bubbles that are closed, and does not absorb water even when wet, so that water is not absorbed and remains in the air bubbles. Therefore, the bacteria and dirt contained in the moisture are not retained in the foamed soot layer 6 and are hygienic. As in the past, hollow spheres such as shirasu balloons were attached to the surface of the earthenware base and fired, and those that were burned with clay mixed with a burnable powder were fired. The bubbles in the formed foam layer are open cells, the foam layer absorbs water, and bacteria and dirt contained in moisture remain in the foam layer and remain difficult to remove by washing, which is a sanitary problem.

  The glaze mixed with the foaming agent used in the present invention may be a normal glaze mixed with the foaming agent.

  The glaze mixed with the foaming agent used in the present invention includes, as a glass forming material, feldspar such as potassium feldspar and soda feldspar, aplite (feldspar feldspar), granite, weathered granite (such as sandstone), volcanic ash, A material selected from glass powder may be used. In the experiment of the present invention, field feldspar or Nissan feldspar, which is a production resource and is inexpensive, was used.

  Moreover, it is preferable that a low thermal expansion material is mixed in the glaze mixed with the foaming agent used in the present invention. The low thermal expansion material is preferable because it can prevent cracking of the foamed soot layer 6 produced by firing in the firing step (at the time of cooling). Examples of the low thermal expansion material include lithium compounds such as petalite, spodumene, eucryptite, and lithium carbonate, cordierite, and the like. Among them, petalite is inexpensive and easily generates low expansion.

  The foaming agent used in the present invention generates gas by decomposition or reduction during firing, and the gas is left in the soot to form pores. Silicon carbide, iron oxide (Bengara), calcium carbonate , Carbon (graphite, charcoal, etc.), aluminum nitride and the like. Among these, silicon carbide and iron oxide have a decomposition temperature suitable for the glass forming temperature of the glass forming material and the low thermal expansion material.

  The number and size of the bubbles in the foam layer 6 can be adjusted by the amount of the foaming agent mixed in the glaze and the firing temperature. When the firing temperature is increased to 1200 ° C. or higher, large bubbles having a diameter of 0.1 to 2 mm are obtained. By adjusting the amount of the foaming agent and the firing temperature, it is possible to easily adjust the feel and heat insulation of the foamed soot layer 6.

  It is preferable that a plasticizer is further blended in the glaze mixed with the foaming agent. This plasticizer is composed of clay consisting of Kibushi clay, Sasame clay, kaolin, bentonite, porcelain stone, etc., or organic paste such as carboxymethylcellulose, gum arabic, dextrin, methylcellulose, biopoly. In the manufacturing process of the heat insulating container 2, the glaze of the glaze mixed with the foaming agent or the layer dried by applying the glaze of the glaze uniformly to the wall surface of the ceramic container substrate 4 by coating or dipping. In order to obtain strength, it is blended in an amount as necessary.

  The composition ratio in the glaze mixed with the foaming agent is 0 to 25 parts by weight of the plasticizer and 0.5 to 15 parts by weight of the foaming agent with respect to 30 to 100 parts by weight of the glass forming material. A foamed soot layer 6 is preferably obtained. When the foaming agent is silicon carbide, the ratio is preferably 0.5 to 2% by weight, and when it is iron oxide, the ratio is preferably 5 to 15% by weight.

  The glaze mixed with the foaming agent is preferably blended with a maximum of 70 parts by weight, preferably 25 to 65 parts of the low thermal expansion material, in order to obtain a uniform foamed glaze layer 6 without cracking or peeling.

  A colorant may be mixed in the glaze mixed with the foaming agent. As the colorant, a colorant such as a pigment for ordinary ceramics such as cobalt oxide, chromium oxide, Taisho black, or ceramic red can be used. In addition, white clay can be mixed to provide a function as a decorative soil.

  In the present invention, by further glazing the surface of the heat insulating container 2, the surface state of the container can be improved and smoothed without impairing the heat insulating properties. In FIG. 3 showing this embodiment, the heat insulating container 2a of this embodiment of the present invention is provided with the foamed soot layer 6 on the wall surface of the ceramic container base 4, and further, the surface of the foamed soot layer 6 is provided with a protective soot. A makeup layer consisting of layer 8 is provided.

  The protective glaze layer 8 may be formed by further glazing on the surface of the heat insulating container 2 using a normal glaze. However, the glaze for forming the protective glaze layer 8 may be used as a glass forming material. A material selected from feldspar such as feldspar and soda feldspar, aplite (feldspar feldspar), granite, weathered granite (such as sandstone), volcanic ash, and glass powder may be used. Of these, field feldspar or Nissan feldspar is preferred.

  Also, the glaze mixed with the foaming agent for forming the foamed glaze layer 6 is applied to the wall surface of the unglazed ceramic container base to form a layer before baking of the glaze mixed with the foaming agent, A layer before the glaze for forming the protective glaze layer 8 is formed by further applying a glaze for forming the protective glaze layer 8 on the surface of the glaze before mixing with the foaming agent. A ceramic container base in an unglazed state, a layer before firing of the glaze mixed with a foaming agent, and a layer before firing of the glaze for forming the protective glaze layer 8 are simultaneously fired and fired. Thus, the heat insulating container 2a can be obtained. Thus, in the manufacturing method of this invention, the heat insulation container 2a can be obtained by one main baking baking, and a process is simple.

  Moreover, it is preferable that a low thermal expansion material is mixed in the glaze for forming the protective cover layer 8. The low thermal expansion material is preferable because it can prevent cracking of the protective filing layer 8 in the firing step (at the time of cooling). Examples of the low thermal expansion material include lithium compounds such as petalite, spodumene, eucryptite, and lithium carbonate, cordierite, and the like. Of these, petalite is preferable.

  The glaze for forming the protective glaze layer 8 is preferably further mixed with a plasticizer. Examples of the plasticizer include clays composed of Kibushi clay, Sasame clay, kaolin, bentonite, porcelain stone, and the like, or organic pastes such as carboxymethylcellulose, gum arabic, dextrin, methylcellulose, and biopoly.

  The proportion of the composition in the glaze for forming the protective glaze layer 8 is that the plastic glaze layer 8 is thin and uniform, being 0 to 40 parts by weight of the plasticizer with respect to 30 to 100 parts by weight of the glass forming material. Obtained and preferred.

  The glaze for forming the protective glaze layer 8 is further preferably blended with a maximum of 70 parts by weight, preferably 25 to 65 parts of a low thermal expansion material.

  A colorant may be mixed in the glaze for forming the protective glaze layer 8. As the colorant, a colorant such as a pigment for ordinary ceramics such as cobalt oxide, chromium oxide, Taisho black, and ceramic red can be used. In addition, white clay can be mixed to provide a function as a decorative soil.

  Table 1 shows compounding examples (units: parts by weight) of glaze mixed with a foaming agent used in the present invention as A to E.

  Table 2 shows compounding examples (units: parts by weight) of glazes further applied to the surface of the heat insulating container 2 used in the present invention as AA to EE.

Example 1
A pottery fabric using Shigaraki's porcelain clay was formed into a bottle shape of the shape shown in FIG. The height of the molded body 12 was 15 cm, the maximum diameter was 10 cm, and the thickness of the peripheral wall was 8 mm.

  Two molded bodies 12 were fired at 800 ° C. to obtain two unglazed containers. One unglazed container was baked by applying a normal glaze to the inner and outer wall surfaces to obtain a glazed porcelain container. The other unglazed container was baked by applying a normal glaze to the inner wall and a glaze containing a foaming agent to the outer wall. The blend of the glaze containing the foaming agent was 100 parts of field feldspar, 3 parts of bentonite, and 0.5 part of silicon carbide, and was adjusted to the same viscosity as that of a normal glaze by adding water. The main baking was performed under the condition that the temperature was raised to 1000 ° C. over 5 hours, raised to 1250 ° C. over 5 hours and maintained at 1250 ° C. for 30 minutes. Thereby, the heat insulation container in which the layer of the foaming ridge with a thickness of 4 mm was uniformly formed on the surface of the main body substrate was obtained.

  While this glazed ceramic container feels cold when it is held, this insulated container is warm to the touch. In the foamed soot layer, the bubbles were closed cells.

  After simultaneously pouring 90 ° C. hot water into each of the glazed ceramic container and the heat insulating container, the surface temperature of the outer peripheral wall surface was measured by a thermograph (manufactured by Nippon Avionics Co., Ltd.) after 2 minutes. The surface temperature of the central portion 14 of the outer peripheral wall surface as measured in the height direction of the container was 71 ° C. for the glazed porcelain container and 63 ° C. for the heat-insulated container.

  Further, the thermal conductivity W / (mk) of the surface of the glazed porcelain container and the heat insulating container at 30 ° C. was 0.901 and 0.879, respectively. Thermal conductivity was measured using a Chemthern QTM-D3 rapid thermal conductivity meter.

  A steel ball having a diameter of 10 mm was dropped from a height of 1 m to a horizontal portion of the foamed slag layer with this heat insulating container turned sideways, but no visible damage occurred on the surface of the foamed slag layer.

Example 2
In order to form a protective layer on the heat insulating container similar to the heat insulating container obtained in Example 1, glaze was applied again to obtain a glazed heat insulating container. The composition of the glaze was 50 parts of field feldspar, 50 parts of petalite, and 2 parts of bentonite, and water was added to adjust the viscosity to be the same as that of a normal glaze and applied in the same manner as a normal glaze. This glazed heat insulating container had almost the same feel as the glazed porcelain container of Example 1. After the pouring of 90 ° C. hot water is completed, the surface temperature at the center of the outer peripheral wall surface in the height direction of the container after 2 minutes has passed is 63 ° C., almost the same as that of the heat insulating container of Example 1. Met.

Example 3
A heat insulating container was obtained in the same manner as in Example 1 except that the composition of the glaze containing the foaming agent was 50 parts of field feldspar, 50 parts of petalite, and 0.5 parts of silicon carbide. The insulated container was warm to the touch. In addition, no cracks were observed on the surface of the foamed soot layer after firing of the main baking. After the pouring of 90 ° C. hot water was completed, the surface temperature of the central portion of the outer peripheral wall surface in the height direction of the container after 2 minutes was 63 ° C.

Example 4
A glaze containing a foaming agent having the same composition as that used in Example 1 is applied to the handle portion of the clay base for the clay pot, and the main baking is performed in the same manner as in Example 1 to form a foamed cocoon layer on the handle portion. An insulated container for a clay pot was obtained. Immediately after being heated at the time of cooking, the handle of the heat insulating container could be grasped by hand. Further, the foamed soot layer formed by heating during cooking did not crack.

Example 5
A glaze containing a foaming agent having the same composition as used in Example 1 is applied to the back surface of the clay base 22 of the clay pot lid 20 having the shape shown in FIG. Layer 6a was formed. An earthenware pot having a foamed cocoon layer formed on the back side of the lid was obtained. The clay pot using this lid had a shorter time until the charged contents were boiled than the clay pot using a normal lid, and the heated contents after heating were difficult to cool.

  In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.

  The insulated container of the present invention is widely applied not only to tableware and cookers such as bowls, cups, pots, mugs, and pans, but also to containers for storing, transporting, or processing hot or cold items. I can do it. Furthermore, the lids and handles of these containers are formed with a layer of foamed foam as in the present invention, and can be widely applied to containers for storing, transporting or processing high temperature or low temperature materials. .

It is a cross-sectional schematic diagram which shows an example of a structure of the heat insulation container of this invention. It is a cross-sectional schematic diagram which shows an example of a structure of the heat insulation container of the aspect different from FIG. 1 of this invention. It is a cross-sectional schematic diagram which shows the structure of the heat insulation container of the other aspect of this invention. It is a cross-sectional schematic diagram which shows an example of the structure of the cover of the earthenware pan of the heat insulation container of the further another aspect of this invention in Example 5. FIG. It is a perspective view which shows the shape of the molded object used for preparation of the heat insulation container of this invention in Example 1. FIG.

Explanation of symbols

2, 2a, 2b: Insulated container 4: Ceramic container base 6, 6a: Layer of foam
7: Air bubbles 8: Layer of protective gutter 12: Molded body

Claims (13)

A heat-insulating container comprising a layer of foamed foam on at least a part of a wall surface of a ceramic container base. The heat insulating container according to claim 1, wherein a protective ridge layer is formed on a wall surface of the foam ridge layer. The layer of foaming foam is obtained by firing a glaze mixed with a foaming agent,
The glaze is
The heat insulating container according to claim 1 or 2, comprising 30 to 100 parts by weight of a glass forming material and 0.5 to 10 parts by weight of the foaming agent. The glaze further comprises
The heat insulation container according to claim 3, comprising 5 to 70 parts by weight of a low thermal expansion material. The glaze further comprises
The heat insulating container according to claim 3 or 4, comprising 1 to 15 parts by weight of a plastic material. The heat insulation container in any one of Claims 3 thru | or 5 in which the said glass forming material contains a feldspar. The heat insulation container according to any one of claims 4 to 6, wherein the low thermal expansion material includes petalite. The heat insulating container according to any one of claims 3 to 7, wherein the foaming agent is selected from silicon carbide and iron oxide. The heat insulating container according to any one of claims 3 to 8, wherein the glaze contains makeup mud. Preparing an unbaked container,
Preparing a glaze mixed with a foaming agent that generates gas by heating,
Attaching the glaze mixed with the foaming agent to the wall surface of the unglazed container;
A method for producing a heat-insulating container, comprising a firing step in which the unglazed container with the glaze mixed with the foaming agent is fired to form a foamed foam layer on the wall surface. Furthermore, the manufacturing method of the heat insulation container of Claim 10 including the process of glazing on the wall surface of the layer of the formed said foam candy. The manufacturing method of the heat insulation container of Claim 10 or 11 in which the said glaze contains makeup mud. The manufacturing method of the heat insulation container in any one of Claims 10 thru | or 12 with which baking in the said baking process is made at 1100-1350 degreeC.

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