Process for the manufacture of photopolymer plates
First Claim
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1. A continuous process for the manufacture of photopolymer plates, comprising the steps of:
- (a) introducing into a screw extruder a photopolymerizable mixture comprising at least one thermoplastic elastomeric polymer, at least one ethylenically mono- or poly-unsaturated compound which can be polymerized by free radicals and has a boiling point of more than about 100°
C. at atmospheric pressure and at least one compound capable of initiating polymerization of said unsaturated compound upon exposure to actinic light;
(b) melting and degassing said mixture in said extruder to form a melt;
(c) metering said melt into a sheet die; and
then(d) conveying said melt into a roll gap of a two-roll calender at such a rate that substantially no rotating bead is formed in said roll gap.
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Abstract
A continuous process for the manufacture of photopolymer plates having a precise and constant thickness in which the components of the photopolymer layer are melted in a screw extruder, the melt is conveyed to the sheet die by means of a gear pump and then into a roll gap of a calender, wherein the melt leaving the sheet die does not form a rotating bead in the calender gap downstream therefrom. The photopolymer plates prepared in this manner have high homogeneity of the components of the photopolymerizable mixture, have a highly precise and constant thickness, are transparent, do not tend to form specks and guarantee a long shelf life.
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Citations
27 Claims
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1. A continuous process for the manufacture of photopolymer plates, comprising the steps of:
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(a) introducing into a screw extruder a photopolymerizable mixture comprising at least one thermoplastic elastomeric polymer, at least one ethylenically mono- or poly-unsaturated compound which can be polymerized by free radicals and has a boiling point of more than about 100°
C. at atmospheric pressure and at least one compound capable of initiating polymerization of said unsaturated compound upon exposure to actinic light;(b) melting and degassing said mixture in said extruder to form a melt; (c) metering said melt into a sheet die; and
then(d) conveying said melt into a roll gap of a two-roll calender at such a rate that substantially no rotating bead is formed in said roll gap. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification