The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 21, 1979
Filed:
Jan. 12, 1977
Paul R Raine, Cardiff, GB;
Lawrence Westcott, Bridgend, GB;
Wiggins Teape Limited, Hampshire, GB;
Abstract
A method of producing self-contained pressure-sensitive copying material having a coating which contains both a particulate mineral color-developing material and microcapsules enclosing a solution of a colorless color former which is reactive with the color developing material to produce a colored product, in which the particles of color developing material (e.g. an acidic clay) and optionally the microcapsules as well, are treated with a protective agent to inhibit premature color development. The protective agent may be a self-crosslinkable polymer, such as an aminoplast polymer (e.g. a urea-formaldehyde or melamine-formaldehyde polymer), or a epichlorohydrin polymer (e.g. an aminoepichlorohydrin or an amide/aminoepichlorohydrin polymer), or an anionic surfactant (e.g. a lauryl sulphate salt or a sulphonated ricinoleic acid derivative, a dodecyl benzene sulphonate salt, or a dibutyl or dioctyl ester of sulphosuccinic acid), or a fluorine-containing paper sizing agent, or a non-self-crosslinkable polymer which is a wet-strength agent for paper (e.g. a polyethylene imine resin).