Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Cellular products or processes of preparing a cellular...
Reexamination Certificate
1998-07-09
2002-06-04
Dye, Rena L. (Department: 1772)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Cellular products or processes of preparing a cellular...
C521S125000, C521S149000, C521S091000
Reexamination Certificate
active
06399668
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a gelling material for aqueous fluids, such as body fluids like urine, blood, etc., medical wastes like dental wastes, various industrial wastes, water-containing sludge-like wastes, meal wastes having high water content, etc.
BACKGROUND OF THE INVENTION
Known compounds for gelling aqueous fluids, such as body fluids like urine, blood, etc., medical wastes like dental wastes, various industrial wastes, water-containing sludge-like wastes, meal wastes having high water content, etc., include: an inorganic compounds such as bentonite, etc., water-soluble resins such as carboxymethyl cellulose (CMC), polyacrylic acid, etc., water-absorbent resins such as a partially neutralized crosslinked polymer of polyacrylic acid, etc.
To enable easy handling of the above-mentioned inorganic compounds, water-soluble resins, water-absorbent resins, etc., (hereinafter all referred to as water-absorbent resins), various gelling materials have been proposed, wherein water-absorbent resin in the form of powders is wrapped in a bag composed of a water-soluble sheet such as a polyvinyl alcohol film, etc., (hereinafter referred to as a water-absorbent bag), for example, as. disclosed in European Patent No. 494,599.
In order to make the aqueous fluids gel in a short period of time, it is important to bring the water-absorbent resin fully in contact with the aqueous fluid quickly. However, the described conventional gelling materials have the following problems. A long time is required for the water-soluble bag to be dissolved almost completely after the gelling material is added to the aqueous fluid, which causes an unfavorable result that the water-absorbent resin cannot be brought fully in contact with the aqueous fluid until the water-soluble bag is dissolved almost completely. Moreover, it is likely that the dissolved water-soluble bag forms a viscous film so as to surround the water-absorbent resin, which disturbs the expansion of the water-absorbent resin. The described water-absorbent resin has a relatively low water-absorbing rate. Therefore, the described conventional gelling materials have the following problems: Since it takes time for the aqueous fluids to be gelled, the aqueous fluids cannot be processed in a short period of time, and a troublesome operation of agitating the aqueous fluids is required when processing them.
When the gelling material is preserved for a long period of time, the water-absorbent resin absorbs moisture in the air and condenses (so-called caking), etc., which likely to causes a clod to be formed in the water-absorbent resin. For this reason, the water-absorbing capacity of the water-absorbent resin cannot be fully exhibited. The clod formed in the water-absorbent resin makes the gelling process of the aqueous fluids troublesome as the gelling process must be carried out while agitating the aqueous fluids.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a gelling material which permits aqueous fluids to be gelled in a short period of time by dispersing water-absorbent resin in the aqueous fluids quickly and uniformly and adjusting various water-absorbing properties of the water-absorbent resin.
In order to achieve the above object, the gelling material of the aqueous solution in accordance with the present invention is characterized by comprising:
water-absorbent resin wrapped in a bag that is water-soluble at least partially, the water-absorbent resin being prepared so as to enable the bag to be disintegrated by an inner pressure generated when an expanded volume of the water-absorbent resin by absorbing water through said bag exceeds a maximum volume capacity.
According to the described arrangement, since it will not take time for the aqueous fluids to be gelled, the aqueous fluids can be processed speedily. Therefore, even the aqueous fluids which are difficult to be processed by the conventional gelling materials can be gelled conveniently in a short period of time, thereby enabling an easy disposal of the aqueous fluids, i.e., gell. Moreover, the water-absorbent resin is spread in the aqueous fluids at a stroke and is dispersed therein uniformly, the troublesome operation of agitating the aqueous fluids during the gelling process of the aqueous fluids can be eliminated, thereby providing a simplified gelling process.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.
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Harada Nobuyuki
Miyake Koji
Odanaka Hiroshi
Dye Rena L.
Kubovcik & Kubovcik
Nippon Shokubai Co. , Ltd.
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