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US 4,060,032 AGranted
Substrate for composite printing and relief plate
AssigneeLaser Graphic Systems Corporation
InventorCharles P. Evans
Life of this patent
Estimating the term…
Abstract
A composite structure for making printing plates and other surfaces in relief is improved by reducing the density of a polymer substrate thereby increasing the amount of material removed per unit of time by a given total amount of energy. The density of the polymer substrate is reduced by making it cellular or poriferous using expandable micro capsules made of thermoplastic shell and a nucleus of a liquified blowing agent.
Claims5
A composite plate, comprising:
- a dimensionally stable cellular polymer substrate selectively removable on exposure to a developing radiation of first wavelength,
- a writing layer overlying the surface of said substrate selectively removable on exposure to a writing radiation of second wavelength but not removable on exposure to said developing radiation, and
- said polymer substrate being selected from the group consisting of cellulose nitrate, methyl methacrylate and ethyl cellulose and cross-linked with trimethylol propane trimethacrylate.
A composite plate, comprising:
- a dimensionally stable cellular polymer substrate selectively removable on exposure to a developing radiation of first wavelength,
- a writing layer overlying the surface of said substrate selectively removable on exposure to a writing radiation of second wavelength but not removable on exposure to said developing radiation,
- said polymer substrate being selected from the group consisting of cellulose nitrate, methyl methacrylate and ethyl cellulose and cross-linked with trimethylol propane trimethacrylate,
- a polymer barrier layer more absorptive of said developing radiation than said polymer substrate, and
- said barrier layer being interposed between said writing layer and polymer substrate.
2 more elements
Dependencies are inferred from the claim text.