Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Patent
1997-05-22
1998-06-30
Foelak, Morton
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
521114, 521130, C08G 1800
Patent
active
057734828
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a thermal insulating foamed material which is used for a refrigerator, freezer and the like, a method for producing the same, and a thermal insulating cabinet filled with the thermal insulating foamed material.
BACKGROUND ART
A thermal insulating foamed material of a foamed urethane resin wherein a blowing is performed by evaporating a blowing agent in the reaction process has hitherto been produced by mixing a polyol composition containing a blowing agent, a foam stabilizer and an urethane reaction catalyst with polyisocyanate with stirring.
Recently, environmental pollution or disruption such as depletion of ozone layer or global warming by chlorofluorocarbons (hereinafter abbreviated to "CFC") or hydrochlorofluorocarbons (hereinafter abbreviated to "HCFC") has been a social problem, and thus a reduction in or a complete abolishment of the use of specific CFC substances such as trichloromonofluoromethane (CFC-11), which is a blowing agent, has been contemplated. Therefore, a substance almost free from environmental pollution or disruption, for example, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) and hydrocarbon (hereinafter abbreviated to "HC") such as cyclopentane has been used as the blowing agent. However, a reduction in amount of HCFC used has been proceeded because HCFC has an ozone depletion coefficient. A HC blowing agent has a vapor thermal conductivity larger than that of conventional CFC-11, thereby to increase a thermal conductivity of the resultant polyurethane foamed material.
When the polyurethane foamed material is produced using the above-mentioned compound as a volatile blowing agent, water is used as a reactive blowing agent for the purpose of improving the blowing efficiency, in addition to the volatile blowing agent. In that case, carbon dioxide produced by the reaction between water and polyisocyanate exists in the closed cells of the polyurethane foamed material, in addition to a vapor of the volatile blowing agent. That is, water added reacts with an isocyanate group and the volatile blowing agent is evaporated by reaction heat, thereby to perform blowing. In addition, blowing is also performed by carbon dioxide evolving as a result of reaction between water and the isocyanate group. Even if water is not added, carbon dioxide evolves by the carbodiimide reaction wherein a part of isocyanate groups reacts with each other. However, the vapor thermal conductivity of carbon dioxide is generally higher than that of the volatile blowing agent. Therefore, there is a problem that carbon dioxide exists in the closed cells and a thermal insulating property of the polyurethane foamed material is deteriorated when a ratio of carbon dioxide in vapor increases.
In order to improve the thermal insulating property of the polyurethane foamed material, a trial of decreasing the proportion of carbon dioxide in the closed cells has hitherto been made. There is a proposal to improve the thermal insulating property of the polyurethane foamed material by fixing carbon dioxide having a poor thermal insulating property, which exists in the closed cells (Japanese Laid-Open Patent Publication Nos. Hei 7-53757 and Hei 7-173314). When using this technique, only carbon dioxide exists in the closed cells in the case of using water alone as the blowing agent and the inside of the closed cells becomes a vacuum state by fixing this carbon dioxide, thereby to improve the thermal insulating property. When using a volatile blowing agent having a low vapor thermal conductivity, the closed cells are filled with carbon dioxide, produced by the reaction between water added and the isocyanate group or carbodiimide reaction, and a vapor of the volatile blowing agent as mentioned above. Then, only the vapor of the volatile blowing agent having a low vapor thermal conductivity remains in the closed cells by fixing carbon dioxide, thereby to improve the thermal insulating property.
For example, in the proposal by Japanese Laid-Open
REFERENCES:
patent: 4578452 (1986-03-01), Kleeberg
patent: 5256726 (1993-10-01), Muller et al.
patent: 5389695 (1995-02-01), Jaster et al.
patent: 5464949 (1995-11-01), Markovitz
patent: 5567739 (1996-10-01), Ward, III
Hashida Takashi
Inagaki Fumihiro
Kishimoto Yoshio
Nakamoto Hideo
Sonoda Nobuo
Foelak Morton
Matsushita Electric - Industrial Co., Ltd.
Matsushita Refrigeration Company
LandOfFree
Thermal insulating foamed material, method for producing the sam does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Thermal insulating foamed material, method for producing the sam, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Thermal insulating foamed material, method for producing the sam will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1859907