US 7,563,845 B2
Amino resin crosslinked particles and producing process thereof
Yasuhiro Yamamoto, Himeji (Japan); and Yasuhiro Shingai, Himeji (Japan)
Assigned to Nippon Shokubai Co., Ltd., Osaka (Japan)
Filed on Oct. 31, 2005, as Appl. No. 11/261,590.
Application 11/261590 is a division of application No. 10/253896, filed on Sep. 25, 2002, granted, now 7,026,050.
Claims priority of application No. 2001-304285 (JP), filed on Sep. 28, 2001.
Prior Publication US 2006/0051581 A1, Mar. 09, 2006
Int. Cl. C08L 61/00 (2006.01)
U.S. Cl. 524—843  [528/269; 528/499] 8 Claims
 
1. A producing process of amino resin crosslinked particles, comprising the steps of:
(1) adding a catalyst to an emulsion of an amino resin precursor that is obtained as an initial condensate by a reaction of an amino compound with formaldehyde, the emulsion being a mixture of a reaction solution containing the amino resin precursor with an aqueous solution of an emulsifier and/or a surfactant the reaction solution containing the amino resin precursor having a viscosity of 2×10−2 Pa·s to 5.5×10−2 Pa·s (20 cP to 55 cP) in a temperature range of 95° C. to 98° C., so as to cure the amino resin precursor in an emulsion state to prepare a suspension that contains amino resin particles;
(2) neutralizing the suspension that contains the amino resin particles obtained in said step (1); and
(3) separating the amino resin particles from the suspension after said step (2) and then heating the amino resin particles in a temperature range of 130° C. to 230° C., the suspension containing the amino resin particles being adjusted in said step (2) from a pH of 1.5 to 3 to a pH of not less than 5.