Flexographic printing form precursor and a method for making the precursor

Patent metadata

Field	Value
Publication number	US-2022016879-A1
Application number	US-201917413339-A
Country	US
Kind code	A1
Filing date	Dec 11, 2019
Priority date	Dec 11, 2018
Publication date	Jan 20, 2022
Grant date	—

Abstract

The invention pertains to a photosensitive element, particularly a photopolymerizable printing form precursor; and, a process of making the photosensitive element. The printing form precursor includes a cover sheet, a layer of a photosensitive composition, and a digital layer, or infrared ablation layer, that is adjacent to a side of the photosensitive layer. A microcell patterned is embossed onto the infrared ablation layer or an overcoat/barrier layer on the infrared ablation layer. Since the microcell pattern layer is integral with the printing form precursor, digital imaging can occur rapidly with relatively low resolution optics to form a mask without needing to also form a microcell pattern of the digital layer. The printing form precursor having the integrated microcell pattern layer facilitates the preparation of relief printing forms to have a print surface suitable for printing solids with uniform, dense coverage of ink.

First claim

We claim:

1 . A printing form precursor comprising:
(a) a photopolymerizable layer comprising a first binder, a monomer, and a photoinitiator, wherein said photopolymerizable layer is supported by a support layer; (b) an infrared ablation layer that is ablatable by infrared radiation and opaque to non-infrared actinic radiation, the infrared ablation layer comprising:
(i) at least one infrared absorbing material;
(ii) a radiation opaque material, wherein (i) and (ii) can be the same or different; and
(iii) at least one second binder;

wherein said infrared ablation layer is embossed with a microcell pattern on the side facing the photopolymerizable layer; and
(c) a coversheet.

2 . The printing form precursor of claim 1 , wherein said infrared ablation layer is embossed with a microcell pattern, and is applied by lamination to a surface of the photopolymerizable layer that is opposite the support.

3 . The printing form precursor of claim 1 , wherein said infrared ablation layer has a transmission optical density of greater than 2.0.

4 . The printing form precursor of claim 1 , wherein said microcell pattern comprises a plurality of features wherein each feature has an area of between 5 to 750 square microns.

5 . The printing form precursor of claim 1 , wherein said first binder is different from said second binder.

6 . A printing form precursor comprising:
(a) a photopolymerizable layer comprising a first binder, a monomer, and a photoinitiator, wherein said photopolymerizable layer is supported by a support layer; (b) an infrared ablation layer that is ablatable by infrared radiation and opaque to non-infrared actinic radiation, the infrared ablation layer comprising:
(i) at least one infrared absorbing material; and
(ii) a radiation opaque material, wherein (i) and (ii) can be the same or different; and
(iii) at least one second binder;

wherein said an infrared ablation layer contains an overcoat/barrier layer which is thermally embossable on the side facing the photopolymerizable layer and is embossed with a microcell pattern; and
(c) a coversheet.

7 . A printing form precursor comprising:
(a) a coversheet: (b) a release layer, wherein said release layer is embossed with a microcell pattern on the side opposite the coversheet; and (c) a photopolymerizable layer comprising a binder, a monomer, and a photoinitiator, wherein said photopolymerizable layer is between the release layer and a support layer.

8 . A method of making a printing form precursor comprising:
a) providing a clear thermal polymer cover sheet; b) providing an infrared ablation composition forming an infrared ablation layer on the cover sheet, the infrared ablation composition comprising (i) at least one infrared absorbing material; (ii) a radiation opaque material, wherein (i) and (ii) can be the same or different; and (iii) at least one second binder; c) embossing the infrared ablation layer with a microcell pattern on the side opposite the cover sheet; and d) applying a photopolymerizable composition forming a photopolymerizable layer between the infrared ablation layer and a support layer, the photopolymerizable composition comprising a first binder, a monomer, and a photoinitiator.

9 . A method of making a printing form precursor comprising:
a) providing a clear thermal polymer cover sheet; b) applying an infrared ablation composition onto the cover sheet to form an infrared ablation layer, the infrared ablation composition comprising (i) at least one infrared absorbing material; (ii) a radiation opaque material, wherein (i) and (ii) can be the same or different; and (iii) at least one second binder; c) applying an overcoat/barrier layer which is thermally embossable onto the infrared ablation layer; d) embossing the overcoat/barrier layer on the side opposite the cover sheet with a microcell pattern; and e) applying a photopolymerizable composition forming a photopolymerizable layer between the overcoat/barrier layer and a support layer, the photopolymerizable composition comprising a first binder, a monomer, and a photoinitiator.

10 . A method of making a printing form precursor comprising the steps of:
a) providing a clear thermal polymer cover sheet; b) applying a release layer that is thermally embossable; c) embossing the release layer on the side opposite the cover sheet with a microcell pattern; and d) applying a photopolymerizable composition forming a photopolymerizable layer between the release layer and a support layer, the photopolymerizable composition comprising a binder, a monomer, and a photoinitiator.

11 . The method of claim 9 , further comprising the steps of:
e) removing the coversheet; and f) applying a mask on top of the release layer.

Assignees

• Dupont Electronics Inc

Inventors

• Blomquist Robert M
• Lungu Adrian

Classifications

• B41C1/08 Primary

  by embossing, e.g. with a typewriter (typewriters adapted therefor B41J3/38) · CPC title

• G03F7/202

  Masking pattern being obtained by thermal means, e.g. laser ablation · CPC title

• G03F7/0002 Primary

  Lithographic processes using patterning methods other than those involving the exposure to radiation, e.g. by stamping · CPC title