Amino resin crosslinked particles and producing process thereof

Amino resin crosslinked particles that are obtained by condensation of an amino compound with formaldehyde,

• wherein the amino resin crosslinked particles generate formaldehyde in an amount of not more than 1000 ppm in a pyrolysis test, and
• wherein the amino resin crosslinked particles have a characteristic that a Hunter whiteness is not less than 85 percent.

Colored amino resin crosslinked particles that are produced by condensation of an amino compound with formaldehyde,

• the colored amino resin crosslinked particles having a characteristic that an area ratio of a carbon atom signal that originates from an —NH—CH2—NH— bond (C(II) bond) to a carbon atom signal that originates from an —NH—CH2O—CH2—NH— bond (C(I) bond) in a solid-state 13C-NMR analysis is not less than 2, and
• the colored amino resin crosslinked particles having a characteristic that a color difference is not more than 15 in a heat discoloring test.

Colored amino resin crosslinked particles that are obtained by condensation of an amino compound with formaldehyde,

• the colored amino resin crosslinked particles generating formaldehyde in an amount of not more than 1000 ppm in a pyrolysis test, and
• the colored amino resin crosslinked particles having a characteristic that a color difference is not more than 15 in a heat discoloring test.

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 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, so as to cure the amino resin precursor in an emulsion state to prepare a suspension that contains amino resin particles;
• and
• (2) heating the amino resin particles in an atmosphere of inert gas that contains oxygen in a concentration of not more than 10 percent by volume and in a temperature range of 130° C. to 230° C.