Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Patent
1991-12-26
1994-11-29
Michl, Paul R.
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
523344, 528481, 528483, 425222, 525 5426, 525 5424, C08F 600, B01J 216
Patent
active
053691482
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a method for the continuous agglomeration of an absorbent resin powder by agglomerating minute particles contained in the absorbent resin powder thereby adjusting particle sizes of the resin powder within a fixed range and to an apparatus for the execution of this method.
BACKGROUND ART
In recent years, the absorbent resin powder has come to find utility in various fields specializing in such hygienic articles as sanitary napkins and disposable diapers and water-retaining agents. The absorbent resin of this quality has been generally produced by polymerizing a resinous raw material, drying the resultant polymer, and pulverizing the dry polymer with a pulverizer. The absorbent resin powder resulting from the pulverization, therefore, contains minute particles short of desired particle sizes. When the absorbent resin powder containing the minute particles is put to use, it has the disadvantage that the minute particles are drifted.
Thus, the practice of incorporating a drift-preventing agent in the resin powder for the purpose of improving the dry flowing property of the resin powder as disclosed in the specification of JP-A-52-121,658 and the practice of incorporating a dust-proofing agent in the resin powder for the purpose of curbing the drifting of minute particles contained in the resin powder as taught in the specification of JP-A-63-39,934 have been heretofore followed.
Further, the method for effecting removal of the minute particles from the resin powder by the use of a sieve and the method for enlarging only the minute particles in the resin powder by the use of a binder have been conceived. The former method, however, is undesirable on account of poor economy. The latter method generally requires use of an organic solvent type binder and, therefore, not only entails the danger of ignition during the step of drying subsequent to the size enlargement but also jeopardizes the biological safety owing to the residue of the organic solvent. The latter method is liberated from this problem when the binder to be used therein is in the form of an aqueous solution. Since the absorbent resin powder produced by pulverization with a binder has the nature of quickly absorbing the aqueous solution, however, the aqueous solution encounters difficulty in allowing uniform dispersion and mixture of the minute particles therein and the agglomeration tends to form large lumps of high density. When the large lumps are to be pulverized, this pulverization entails occurrence of minute particles and produces uniformly aggregated particles only with difficulty.
For the solution of this problem, the method which as taught in JP-A-61-97,333 and JP-A-61-101,536 comprises uniformly mixing the absorbent resin powder and an aqueous liquid and agglomerating the resultant mixture by the use of a specific mixing device such as, for example, a high-speed rotary paddle type mixer or an air current type mixer and then crushing the produced agglomerate has been heretofore tried.
It has been found, however, that the method which effects the mixture of the absorbent resin powder with the aqueous liquid by virtue of the shearing force of the high-speed rotary type mixer as described above produces a powder of an unduly small basic particle diameter. This adverse phenomenon may be logically explained by a supposition that when the resin powder is mixed by stirring in the mixer, the component particles of this powder undergo repetitious mutual collision and, at the same time, yield to fracture due to mechanical shear. When the particles of the resin powder having the particle surface thereof specially treated in advance for the purpose of qualitative improvement are fractured as described above, the fractured particle surface poses a problem of qualitative degradation.
When the air current type mixer mentioned above is to be adopted, it has a problem of unfitness for commercial production of an absorbent resin powder because it is incapable of continuous stirring. Moreover, the mixer has another
REFERENCES:
patent: 3632257 (1972-01-01), Ashizawa
patent: 4259053 (1981-03-01), Wahli
patent: 4539936 (1985-09-01), Yasui et al.
patent: 4640839 (1987-02-01), Hsu
patent: 4734478 (1988-03-01), Tsubakimoto et al.
patent: 5002986 (1991-03-01), Fujiura et al.
Akihisa Kazumi
Fujiwara Teruaki
Irie Yoshio
Kakita Hiroyuki
Takahashi Hitoshi
Merriam Andrew E. C.
Michl Paul R.
Nippon Shokubai Co. , Ltd.
LandOfFree
Method for continuous agglomeration of an absorbent resin powder does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for continuous agglomeration of an absorbent resin powder, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for continuous agglomeration of an absorbent resin powder will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-74609