US4469775A — Multi-layer elements with polyvinyl alcohol overc…

Claim 1

Independent Claim 182 words

A process for improving the production, drying and shelf life of a multi-layer element which is suitable for the production of a relief printing plate and comprises (a) a dimensionally stable base B and (b) a photosensitive layer R which has a bulk density of from 100 to 70,000 mg/dm 2 and contains a mixture which is soluble or dispersible in an aqueous solvent and comprises (b1) a 2-hydroxyalkyl acrylate and/or methacrylate where alkyl is of 2 or 3 carbon atoms, with or without one or more further photopolymerizable, ethylenically unsaturated monomers, (b2) one or more polyvinyl alcohols which are soluble or dispersible in water and have a degree of hydrolysis of 74-88 mole% and an average degree of polymerization of 200-2,000, and (b3) one or more photoinitiators, wherein a top layer D which is about 0.1-10 μm thick when dry and essentially of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mole% and a viscosity of 2-8 mPa.s (measured as a 4% strength by weight aqueous solution at 20° C.) is applied to the layer R.

Claim 2

Dependent Claim 182 words

A process for improving the production, drying and shelf life of a multi-layer element which is suitable for the production of a relief printing plate and comprises (a) a dimensionally stable base B and (b) a photosensitive layer R which has a bulk density of from 100 to 70,000 mg/dm 2 and contains a mixture which is soluble or dispersible in an aqueous solvent and comprises (b1) a 2-hydroxyalkyl acrylate and/or methacrylate where alkyl is of 2 or 3 carbon atoms, with or without one or more further photopolymerizable, ethylenically unsaturated monomers, (b2) one or more polyvinyl alcohols which are soluble or dispersible in water and have a degree of hydrolysis of 74-88 mole% and an average degree of polymerization of 200-2,000, and (b3) one or more photoinitiators, wherein a top layer D which is about 0.1-10 μm thick when dry and essentially of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mole% and a viscosity of 2-8 mPa.s (measured as a 4% strength by weight aqueous solution at 20° C.) is applied to the layer R.

Claim 3

Dependent Claim 22 words

The process of claim 1, wherein the polyvinyl alcohol of the photosensitive layer R has an average degree of polymerization of 250-700.

Claim 4

Dependent Claim 22 words

The process of claim 1, wherein the polyvinyl alcohol of the photosensitive layer R has a degree of hydrolysis of 80-82 mole%.

Claim 5

Dependent Claim 16 words

The process of claim 1, wherein the top layer is from 0.5 to 5 μm thick.

Claim 6

Dependent Claim 14 words

The process of claim 1, wherein the polyvinyl alcohol is a hydrolyzed polyvinyl acetate.

Claim 7

Dependent Claim 15 words

The process of claim 1, wherein the top layer D contains a finely divided pigment.

Claim 8

Dependent Claim 16 words

The process of claim 6, wherein the top layer D contains a finely divided colored pigment.

Claim 9

Dependent Claim 23 words

The process of claim 6 or 7, wherein the top layer has a rough surface with a peak-to-valley height of about 1-5 μm.

Claim 10

Dependent Claim 79 words

The process of claim 1, wherein the top layer D is applied to the layer R by providing a plastics film with a 0.1-10 μm thick polyvinyl alcohol layer, and producing the layer R on the side bearing the polyvinyl alcohol layer, or bringing the coated film into contact with a layer R, in such a manner that the polyvinyl alcohol layer adheres to the layer R and the film can be peeled off without the polyvinyl alcohol layer.

Claim 11

Dependent Claim 45 words

The process of claim 1, wherein, in the production of the multi-layer element, the top layer D is applied to the photosensitive layer R which still contains water or is moist, and thereafter the water content of the photosensitive layer R is reduced by drying.

Claim 12

Dependent Claim 177 words

A multi-layer element for the production of a relief printing plate which comprises: (a) a dimensionally stable base (B); (b) a photosensitive layer (R) having a bulk density of from 100 to 70,000 mg/dm 2 , said layer (R) containing a mixture which is soluble or dispensible in an aqueous solvent, which mixture comprises: (b1) a 2-hydroxyalkyl acrylate and/or methacrylate, said alkyl having 2 or 3 carbon atoms, with or without one or more additional photopolymerizable, ethylenically unsaturated monomers, (b2) one or more polyvinyl alcohols which are soluble or dispersible in water and have a degree of hydrolysis of 74-88 mole% and an average degree of polymerization of 200-2000, and (b3) one or more photoinitiators; and (c) a layer D on top of layer R and applied to layer R, said layer D being from about 0.1-10 μm thick when dry and consisting essentially of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mole% and a viscosity of 2-8 mPa.s (measured as a 4% strength by weight aqueous solution at 20° C.).

Claim 13

Dependent Claim 177 words

A multi-layer element for the production of a relief printing plate which comprises: (a) a dimensionally stable base (B); (b) a photosensitive layer (R) having a bulk density of from 100 to 70,000 mg/dm 2 , said layer (R) containing a mixture which is soluble or dispensible in an aqueous solvent, which mixture comprises: (b1) a 2-hydroxyalkyl acrylate and/or methacrylate, said alkyl having 2 or 3 carbon atoms, with or without one or more additional photopolymerizable, ethylenically unsaturated monomers, (b2) one or more polyvinyl alcohols which are soluble or dispersible in water and have a degree of hydrolysis of 74-88 mole% and an average degree of polymerization of 200-2000, and (b3) one or more photoinitiators; and (c) a layer D on top of layer R and applied to layer R, said layer D being from about 0.1-10 μm thick when dry and consisting essentially of a polyvinyl alcohol having a degree of hydrolysis of not less than 95 mole% and a viscosity of 2-8 mPa.s (measured as a 4% strength by weight aqueous solution at 20° C.).

Claim 14

Dependent Claim 25 words

A multi-layer element as defined in claim 11, wherein the polyvinyl alcohol of the photosensitive layer R has an average degree of polymerization of 250-700.

Claim 15

Dependent Claim 24 words

A multi-layer element as defined in claim 11, wherein polyvinyl alcohol of the photosensitive layer R has a degree of hydrolysis of 80-82 mole%.

Claim 16

Dependent Claim 19 words

A multi-layer element as defined in claim 11, wherein the top layer is from 0.5 to 5 μm thick.

Claim 17

Dependent Claim 17 words

A multi-layer element as defined in claim 11, wherein the polyvinyl alcohol is a hydrolyzed polyvinyl acetate.

Claim 18

Dependent Claim 18 words

A multi-layer element as defined in claim 11, wherein the top layer D contains a finely divided pigment.

Claim 19

Dependent Claim 19 words

A multi-layer element as defined in claim 11, wherein the top layer D contains a finely divided color pigment.

Claim 20

Dependent Claim 25 words

A multi-layer element as defined in claim 11, wherein the top layer D has a rough surface with a peak-to-valley height of about 1-5 μm.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1987-09-04	1988-03-05	1988-09-04	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1991-09-04	1992-03-05	1992-09-04	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1995-09-04	1996-03-05	1996-09-04	$7700.00	Window Closed / Lapsed

Multi-layer elements with polyvinyl alcohol overcoat suitable for the production of relief printing plates

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag