Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
1999-10-20
2001-10-09
Seidleck, James J. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S086000, C521S088000, C521S094000, C521S095000
Reexamination Certificate
active
06300385
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an organic porous material used for, for example, thermal insulators, and a method of manufacturing the same.
Foamed materials of organic polymers, such as polyurethane, have conventionally been used as porous materials for thermal insulators of, for example, refrigerators. The organic polymers have excellent flexibility but insufficient thermal insulating properties. Inorganic porous materials, especially those of silica material having excellent thermal insulating properties, have thus been produced and used for the thermal insulators.
The porous material of the silica material is obtained by drying a wet gel under supercritical condition and has pores of approximately 50 nm in diameter. The shorter void distance defined by the pores than a mean free path of oxygen and nitrogen depresses heat conduction of the gas and accordingly ensures the better thermal insulating properties than urethane foam even at atmospheric pressure.
The silica, which constitutes the aerogel, however, has disadvantages such as brittleness, difficulty in handling and the like.
Then, the object of the present invention is thus to provide an organic porous material having equivalent thermal insulating properties to those of a porous material of silica material and improved brittleness.
BRIEF SUMMARY OF THE INVENTION
In order to attain at least part of the above and the other related objects, the present invention is directed to an organic porous material comprising aggregated organogel fine particles having a particle diameter of 10 to 300 nm, in which aggregated particles have inter-particle crosslinkings therebetween. In other words, inter-particle crosslinking is formed between adjoining organogel fine particles.
It is preferable that each pore has a diameter of 5 to 100 nm.
It is further preferable that the organogel fine particles have a density of 0.05 to 0.3 g/cm
3
.
In the present invention, the organogel fine particle preferably has an intra-particle crosslinking whose molecular bonding structure is different from that of the inter-particle crosslinking.
In the above arrangement, it is preferable that the organogel fine particles comprises a vinyl polymer, and the inter-particle crosslinking is any one of urethane bond, amide bond, oxazolidone bond, siloxane bond, ester bond, and acetal bond.
The present invention is also directed to a method of producing an organic porous material comprising the steps of:
(a) swelling organogel fine particles having a crosslinkable functional group on surface thereof with a solvent;
(b) making the crosslinkable functional group on the surface of the fine particles to react in the solvent to form inter-particle crosslinking between adjoining organogel fine particles, thereby giving an aggregate of the organogel fine particles; and
(c) drying the aggregate to remove the solvent.
In accordance with one preferable application of the present invention, the method further includes the step of mixing a crosslinking agent after the step (a) and before the reaction of the crosslinking functional group in the solvent in the step (b).
In accordance with another preferable application of the present invention, the method further includes the step of mixing a crosslinking catalyst after the step (a) and before reacting the crosslinking functional group in the solvent in the step (b).
It is preferable that the aggregate is dried in the step (c) by a supercritical drying method.
The present invention is further directed to a method of manufacturing an organic porous material comprising the steps of:
(i) swelling organogel fine particles having a crosslinking functional group on surface thereof with a solvent;
(ii) drying the swelled organogel fine particles by a supercritical drying method; and
(iii) making the crosslinking functional group of the organogel fine particles react to form inter-particle crosslinking between adjoining organogel fine particles, thereby giving an aggregate of the organogel fine particles.
In accordance with one preferable application of the present invention, the method further includes the step of mixing a crosslinking agent after the step (ii) and before the reaction of the crosslinking functional group in the step (iii).
In accordance with another preferable application of the present invention, the method further includes the step of mixing a crosslinking catalyst after the step (ii) and before the reaction of the crosslinking functional group in the step (iii).
These and other objects, features, aspects, and advantages of the present invention will become more apparent from the following detailed description of the present invention with the accompanying drawings.
REFERENCES:
patent: 5102597 (1992-04-01), Roe et al.
patent: 5770631 (1998-06-01), Fukutomi et al.
patent: 5973015 (1999-10-01), Coronado et al.
patent: 07-138375 A (1995-05-01), None
K. Yakota et al. “Chemical industry symposium series” “Drying of Silica Alcogel with supercritica Fluid,” vol. 35, pp. 149-154 (1993) (English language Abstract included).
Hashida Takashi
Ono Yukiyoshi
Suzuki Masa-aki
Akin Gump Strauss Hauer & Feld L.L.P.
Bagwell M D
Matsushita Electric - Industrial Co., Ltd.
Seidleck James J.
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