Sakura Color Products Corporation

Threebond Co., Ltd.

National Maritime Research Institute

Tomio Onoguchi

Hidetoshi Fukuo

Ichihiko Takahashi

Mitsuhiko Uchida

Michio Ushijima

In a coating for the inspection of a crack in a structure wherein a coating layer having dispersed therein microcapsules with a visualizing liquid sealed therein is formed on the surface of the structure and when a crack is developed in the structure and propagated to the coating layer, the microcapsules dispersed in the coating layer are ruptured and the visualizing liquid flows out from the ruptured microcapsules and reaches the surface of the coating layer along the crack in the coating layer, thereby making it possible to detect the occurrence of the crack in the structure: at least one second coating layer not containing the microcapsules is formed over the first coating layer with the microcapsules dispersed therein, the second coating layer being transparent and having an outermost layer flexible enough to be prevented from being cracked even upon cracking in the first coating layer.

Coating for inspection of cracking in structure

A process for manufacturing microcapsules by dissolving or dispersing microcapsule contents in an aqueous solution of acrylic acid-methacrylic acid copolymer and/or acrylic acid-itaconic acid copolymer, then polymerizing urea and/or melamine and formaldehyde in the solution or dispersion adjusted to pH 2.5.about.6.0, and forming film of urea-formaldehyde copolymer, melamine-formaldehyde copolymer, or urea-melamine-formaldehyde copolymer around capusle contents. Microcapsules manufactured by this process are useful for colors for carbonless paper or thermo-changeable colors.

Microcapsule manufacture

Growing community of inventors

Tokyo, Japan

Tomio Onoguchi