| YOSHINO GYPSUM CO., LTD Patent applications |
| Patent application number | Title | Published |
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| 20110135930 | PROCESS FOR CONTINUOUS MODIFICATION OF DIHYDRATE GYPSUM AND MODIFIED DIHYDRATE GYPSUM OBTAINED BY THE PROCESS - Disclosed is a process for the continuous modification of dihydrate gypsum. The process includes a hemihydration step of calcining the dihydrate gypsum as a raw material into hemihydrate gypsum and a recrystallization step of hydrating and recrystallizing the hemihydrate gypsum in an aqueous slurry to convert the hemihydrate gypsum into modified dihydrate gypsum of a crystalline form different from the dihydrate gypsum as the raw material. In the recrystallization step, the aqueous slurry in a recrystallization reaction tank is maintained at a constant temperature under stirring such that the aqueous slurry becomes uniform, and a feed rate of the hemihydrate gypsum to the recrystallization reaction tank and a discharge rate of the recrystallized and modified dihydrate gypsum from the recrystallization reaction tank are controlled such that the feed rate and the discharge rate become substantially equal to each other, whereby the feeding of the hemihydrate gypsum and the discharging of the recrystallized and modified dihydrate gypsum are conducted continuously or intermittently. According to the process, dihydrate gypsum as a starting raw material can be converted into high-purity, modified dihydrate gypsum of large crystals by recrystallizing the starting dihydrate gypsum after it is once calcined into hemihydrate gypsum although such modified dihydrate gypsum is not available in general. | 06-09-2011 |
| 20100190017 | GYPSUM BOARD HAVING MOLD RESISTANCE - A gypsum board having mold resistance includes a gypsum core containing a first anti-mold agent poorly soluble in water and a waterproofing agent; and gypsum board paper containing a second anti-mold agent poorly soluble in water. | 07-29-2010 |
| 20100048372 | SCORING DEVICE FOR GYPSUM BOARD PRODUCTION DEVICE - The invention provides a whetstone type of scoring device for production of gypsum boards which can accurately and stably form a groove of a constant depth on a sheet of paper for gypsum board liner, and which can prevent wear of a rotary blade and a backing block. The scoring device ( | 02-25-2010 |
| 20090256291 | METHODS FOR MANUFACTURING A CALCINED GYPSUM AND A GYPSUM BOARD - The present invention provides a method for manufacturing a calcined gypsum wherein the mixing water amount is reduced and the setting time does not increase. As a raw gypsum is compounded with a carboxylic acid-type material and calcined, a calcined gypsum can be manufactured wherein the mixing water amount is small and the setting time does not increase. Furthermore, a regular gypsum board can be manufactured without reducing the productivity of the gypsum board even if a large quantity of recycled gypsum causing increase of the mixing water amount is used as a raw gypsum, because the mixing water amount is small and the setting time does not increase for the calcined gypsum manufactured as described above. | 10-15-2009 |
