Sanyo Electric Co., Ltd.

Yuji Kishi

Akihiro Morita

Minoru Takezawa

Fumihisa Endo

Shigeo Yatsu

Hiroshi Naganuma

Yoshirou Ishizaka

Kenji Sato

Yoshihisa Ishida

Kiyokazu Goto

A method for the mixing of a polyol with a low-boiling foaming agent for the manufacture of a rigid foamed polyurethane. The polyol is blended in advance with a specific amount of the low-boiling foaming agent such as chlorodifluoromethane (designated by HCFC-22) or the like in a liquid state. In this case, it is possible to uniformly supply the polyol and the specific amount of HCFC-22 to a polyurethane foaming system, resulting in a homogeneous foaming reaction whereby a rigid foamed polyurethane having excellent cell uniformity without any voids may be obtained.

Method for the mixing of low-boiling foaming agent

According to the present invention, there is provided a rigid foamed polyurethane and a process for the manufacture of the polyurethane wherein the polyurethane is made up substantially of closed cells which contain at least a foaming agent designated by HCFC-22 and CO.sub.2 gas therein. The foamed polyurethane can be obtained by using HCFC-22 or a blend of the HCFC-22 with HCFC-142b as foaming agent which has a short life in the atmosphere because of having hydrogen atoms in their molecules. Thus, according to the present invention, it is possible to avoid the use of conventional foaming agents which are suspected of being substances eating a hole in the atmospher's layer of ozone and consequently linking to global warming. The rigid foamed polyurethanes of the present invention, which contain a foaming agent designated by HCFC-22 having a boiling point of -40.8.degree. C. in their closed cells, can retain their good thermal insulating properties over a temperature of from about -30.degree. to -40.degree. C., and can be used for most applications in the extremely cold conditions. Further, when employing a HCFC-22 blend containing a specific amount of HCFC-142b as foaming agent, there is provided a rigid foamed polyurethane having a less change in thermal insulating properties on standing while retaining good flame resistance of the rigid foam.

Rigid foamed polyurethane and process for the manufacture of the same

A refrigeration showcase comprising a display case, a machine case and an air duct connecting the display case to the machine case, the display case comprising a display table for displaying commodities as placed thereon, a cover member openably covering the display table from above to define a commodity chamber above the display table and permitting the commodity chamber to be seen therethrough from outside, and an air passage member disposed under the display table and providing a cold air supply portion for supplying cold air therethrough to the commodity chamber and a cold air discharge portion independent of the supply portion for discharging cold air from the commodity chamber therethrough, the machine case comprising a case body, a refrigerator housed in the case body and providing a refrigeration cycle and a cold air circulating blower for supplying air cooled by the evaporator in circulation, the air duct having a forward air channel for transporting the cold air, and a return air channel independent of the forward air channel.

Refrigeration showcase

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Ohta, Japan

Yuji Kishi