Inner part for a refrigerating device

Abstract

An inner part for a refrigerating device, such as an inner wall, a refrigerating item support, or similar item ideally should be easy to clean. At least a surface of the inner part is provided with effective protection against microbes and/or fungi. Because the inner part inhibits the growth of microbes and/or fungi, it is easier to clean and maintain.

Claims

1. A refrigerating appliance, comprising: a housing encompassing an interior space of the refrigerating appliance, the housing including an outer wall, an inner wall, and an insulating foam layer in an intermediate space between the inner wall and the outer wall, the inner wall facing the interior space, the inner wall having a first layer of material that includes a plastic material and an admixture with a silver compound effective against at least one of microbes or fungi in the interior space of the refrigerating appliance, the first layer forming a surface layer of the inner wall, and a second layer of material, the second layer of material consists of the same plastic material as the first layer, the second layer of the inner wall facing the insulating foam layer.

2. The refrigerating appliance of claim 1, wherein the first layer and the second layer are bonded together by coextrusion of the first layer and the second layer.

3. The refrigerating appliance of claim 1, wherein the silver compound includes silver ions bonded in a zeolite material.

4. A refrigeration appliance, comprising: a housing having an outer wall, an inner wall, and an insulating foam layer in an intermediate space between the inner wall and the outer wall, the housing encompassing an interior space of the refrigeration appliance, wherein the inner wall has a surface layer and a carrier layer, the surface layer facing the interior space of the refrigeration appliance and the carrier layer facing the insulating foam layer; and is made from a divided-up plastics sheet material, the divided-up plastics sheet material being made by coextrusion of a first raw material charge and a second material charge; wherein the first raw material charge forms the surface layer of the inner wall and the second raw material charge forms the carrier layer of the inner wall; wherein the first raw material charge is made of one of a plastics material and a plastics material mixture; wherein the second material charge consists of the same plastics material as the first raw material charge; wherein the first raw material charge is admixed with a silver compound, the silver compound being effective against at least one of microbes or fungi in the interior space of the refrigeration appliance; and wherein the second raw material charge is free of the silver compound.

5. The refrigeration appliance of claim 4, wherein the plastics material comprises a polymer matrix, wherein the silver compound is embedded in the polymer matrix.

6. The refrigeration appliance of claim 4, wherein the plastics material comprises a zeolite material, wherein ions of the silver compound are interchangeably bonded in the zeolite material.

Description

PREFERRED EMBODIMENT OF THE INVENTION

(1) A refrigerating device, such as for example a refrigerator, contains a heat-insulating housing, which surrounds a cooled interior space and can be closed with a door. The housing and the door are constructed in the same way from an outer wall, for example made of painted sheet metal, an inner wall, which is generally produced by thermoforming from flat plastics material, and an insulating foam filling introduced into an intermediate space between the inner wall and the outer wall. Since this construction is generally known, it need not be explained here on the basis of a figure.

(2) In the case of a refrigerator according to the invention, the inner wall of the housing and of the door are provided with a finish that is effective against microbes and/or fungi. The inner wall has a two-layer structure, with a carrier layer that is substantially free from the effective chemical substance, which is facing the insulating foam layer, and a surface layer that is provided with the chemical substance, which is facing the interior space of the refrigerating device.

(3) For producing the inner wall, first a sheet of flat plastic material is produced by coextrusion of two batches of raw material. One batch, forms a carrier layer, of a plastic material or a material mixture which is substantially free from the effective chemical substance, i.e. if it contains the substance at all it is in trace amounts that are not adequate for a microbicidal or fungicidal effect, and a second batch, which contains the same plastic material or material mixture provided with the effective chemical substance, and forms the surface layer.

(4) Examples of suitable effective chemical substances are described in detail in European Patent EP 0 270 129 B1, corresponding to U.S. Pat. No. 4,938,958, which is hereby incorporated by reference herein. Synthetic resin compositions provided with such substances and also concentrations of the effective substances that are suitable for a microbicidal or fungicidal effect are discussed in European Patent EP 0 288 063 B1, corresponding to U.S. Pat. No. 4,759,599, which is hereby incorporated by reference herein. The exemplary embodiments described in these documents are suitable as effective chemical substances or as materials for the production of the surface layer within the scope of the present invention.

(5) The flat material sheet is thermoformed in a way known per se and divided up to form housing or door inner walls. The thickness of the surface layer produced during the coextrusion is dimensioned such that a closed surface layer with a material thickness required for a sustained microbicidal and/or fungicidal effect is retained even after thermoforming.

(6) The interior space of the refrigerating device contains various internal fittings, such as for instance refrigerated-item supports for mounting on the housing, refrigerated-item supports for mounting on the door inner wall, pull-out boxes, trays, etc. The refrigerated-item supports mounted on the housing are made up of glass plates that are enclosed in frame elements made of plastic. These frame elements may be injection-molded parts fitted onto the edges of the plate or be formed directly on the edges of the plate by encapsulation. The pull-out boxes and other boxes and trays fitted in the interior space of the refrigerator, the refrigerated-item supports mounted in the door and other accessories are injection-molded parts made of plastic.

(7) These frame elements and other injection-molded parts may be produced from synthetic resin compositions, as described in the exemplary embodiments of European Patent EP 0 228 063 B1 or defined in the patent claims of this document.

(8) In the production of these injection-molded parts, first a portion of polymer granules is melted and mixed in the molten state with a portion of the chemical substance that is effective against microbes and/or fungi. The portion is dimensioned such that the concentration of the substance in the mixture is a multiple of the concentration desired in the finished injection-molded parts.

(9) The mixture obtained in this way is granulated with a grain size that corresponds to the granules originally used. The granules obtained in this way, referred to as preliminary granules, are mixed with granules that are free from the substance in such a ratio that granules with the concentration configured for the finished inner parts result. Since the grain size of the granules introduced into the mixture is the same and the concentration of the substance in the preliminary granules is so low that the densities of the granules also do not markedly differ, a stable mixture without any segregation tendency is obtained. The mixture is used in a way known per se for producing the inner parts by injection-molding.