Highly absorbent composite and method of making the same

Abstract

A composite structure mainly composed of hydratable fine fibers in the form of microfibril and a water swellable solid body, the fibers being obtained from cellulose or derivatives thereof, and at least part of the surface of the solid body is covered with the fine fibers. The absorbent composite can be formed in various form of, for example, particle, pellet, sheet and the like, especially of a sheet type with a supporting sheet of a non-woven fabric. The present invention further provides a method of making the composite structure.

Description

[0001]This application is a division of U.S. patent application Ser. No. 09 / 242,482 filed Oct. 22, 1999 entitled “Highly Absorbent Composite Compositions, Absorbent Sheets Provided with the Compositions, and Process for Producing the Same” which is a 371 application of PCT / JP97 / 04606 filed Dec. 15, 1997 which claims priority of Japanese Patent Application Number 333520 / 1996 filed Dec. 13, 1996 and Japanese Patent Application Number 124623 / 1997 filed May 15, 1997 and Japanese Patent Application Number 192159 / 1997 filed Jul. 17, 1997 and Japanese Patent Application Number 213222 / 1997 filed Aug. 7, 1997 and Japanese Patent Application Number 313368 / 1997 filed Nov. 14, 1997 and Japanese Patent Application Number 329830 / 1997 filed Dec. 1, 1997, all the disclosures of which are herein incorporated by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a new type absorbent composite wherein a water swellable solid body, particularly co...

AI Technical Summary

Benefits of technology

[0044]The SAP which is used for these purposes should be particles, preferably, fine particles, so that it may be held stably in a small space, and specifically, the diameter of the particles should be 0.4 mm or less, or, more preferably, 0.3 mm to 0.1 mm. Very fine particles, such as those of 0.1 mm diameter, can be coexistent with coarser particles, such as those of 0.4 mm or coarser. In case fiber material such as wood pulp is made to coexist with the SAP, the more the content of the SAP, the better the result: the content of the SAP is preferably 50 percent or higher.

[0045]As discussed in the above, in making the composite absorbent of the present invention, the HFFM, the SAP and, as required, a short-cut staple fiber component are dispersed in a dispersion medium. A particularly effective dispersion medium is a polyvalent alcohol, which has the tendency to be highly viscous at a low temperature and logarithmically to reduce in viscosity as heated. Specifically, by utilizing the behavior in the relation between temperature and viscosity of a mixed system of a polyvalent alcohol and water, the transferring and forming are carried out while the system is stably maintained which is made at a low temperature and highly viscous at the time of dispersion and storing, and the forming and removal of the liquid component are made easier while the system is heated and hydrated at the time of removing the liquid component so that the viscosity is decreased and the liquidity is increased.

Problems solved by technology

Thus, the absorbent product does not work as designed.

However, so far, no successfully commercialized examples have been reported because of high costs of raw materials and high capital investments involved.

However, an absorbent product in which the content of the SAP is made high or the SAP alone is used in order to secure high absorbency has a serious drawback; upon a liquid being discharged at first the SAP starts to absorb it all at once and thus an initial absorbing is very speedy but as the discharging is repeated, the absorbing speed drastically decreases.

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