# US 9,751,353 B2 · Method of improving surface cure in digital flexographic printing plates

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- Number: US 9,751,353 B2
- Document ID: US9751353B2
- Status: Granted
- Kind: B2
- Application number: 15/086,402
- Filed: 2016-03-31
- Published: 2016-07-21
- Granted: 2017-09-05
- Earliest claimed: 2012-08-22
- Applicants: MacDermid Printing Solutions, LLC
- Inventors: Jonghan Choi; Kerry O'Brate
- Web page: https://patentgrep.com/patent/US9751353B2

## CPC

- B41N 1/12: non-metallic other than stone {, e.g. printing plates or foils comprising inorganic materials in an organic matrix (B41N1/003, B41N1/006 take precedence)}
- G03F 7/027: Non-macromolecular photopolymerisable compounds having carbon-to-carbon double bonds, e.g. ethylenic compounds (G03F7/075 takes precedence)
- G03F 7/09: characterised by structural details, e.g. supports, auxiliary layers (supports for printing plates in general B41N)
- G03F 7/20: Exposure; Apparatus therefor (photographic printing apparatus for making copies G03B27/00)
- G03F 7/202: {Masking pattern being obtained by thermal means, e.g. laser ablation}
- G03F 7/325: {Non-aqueous compositions}
- G03F 7/36: Imagewise removal not covered by groups G03F7/30 - G03F7/34, e.g. using gas streams, using plasma
- B41N: PRINTING PLATES OR FOILS (photosensitive material G03); MATERIALS FOR SURFACES USED IN PRINTING MACHINES FOR PRINTING, INKING, DAMPING, OR THE LIKE; PREPARING SUCH SURFACES FOR USE AND CONSERVING THEM
- G03F: PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR; (phototypographic composing devices B41B; photosensitive materials or processes for photographic purposes G03C; electrophotography, sensitive layers or processes therefor G03G)

## Abstract

A photocurable relief image printing element is described. The photocurable relief image printing element comprises (a) a support layer; (b) one or more photocurable layers disposed on the support layer, wherein the one or more photocurable layers comprise: (i) a binder; (ii) one or more monomers; (iii) a photoinitiator; and (iv) an additive selected from the group consisting of phosphites, phosphines, thioether amine compounds, and combinations of one or more of the foregoing; (c) a laser ablatable masking layer disposed on the one or more photocurable layers, the laser ablatable masking layer comprising a radiation opaque material; and (d) optionally, a removable coversheet. The photocurable relief image printing element provides improved surface cure in digital relief image printing elements.

## Claims

### Claim 1

A relief image printing element produced from a photocurable printing blank, wherein the photocurable printing blank comprises:
a) a support layer;
b) one or more photocurable layers disposed on the support layer, wherein the one or more photocurable layers comprise:
i) a binder;
ii) one or more monomers;
iii) a photoinitiator; and
iv) an additive selected from the group consisting of phosphites, thioether amine compounds, and combinations of one or more of the foregoing;
c) a laser ablatable masking layer disposed on the one or more photocurable layers, the laser ablatable masking layer comprising a radiation opaque material; and
d) optionally, a removable coversheet,
wherein the relief image printing element comprises a plurality of relief printing dots which relief printing dots comprise at least one of the following characteristics;
(i) edge sharpness of the relief printing dots, defined as the ratio of the radius of curvature re at the intersection of a shoulder and the top of the relief printing dot to the width of the dot's top printing surface p is less than 5%; or
(ii) average shoulder angle, measured as the angle between a shoulder of the dot across the width of the dot's top printing surface, is less than 30°.

### Claim 2 (depends on 1)

The photocurable relief image printing element according to claim 1, wherein the additive is a phosphite selected from the group consisting of tris(nonylphenyl)phosphite, triphenyl phosphite, diphenyl phosphite, tridecyl phosphite, triisodecyl phosphite, tris(tridecyl)phosphite, trilauryl phosphite, disteraryl pentaerythriol diphosphite, diisodecyl phenyl phosphite, diphenyl isodecyl phosphite, diphenyl octyl phosphite, diphenyl isooctyl phosphite, diphenyl tri isodecyl monophenyl dipropyleneglycol diphosphite, alkyl bisphenol A phosphite, tetraphenyl dipropyleneglycol diphosphite, poly(dipropyleneglycol) phenyl phosphite, tris(dipropylene glycol) phosphite, and dioleyl hydrogen phosphite and combinations of one or more of the foregoing.

### Claim 3 (depends on 2)

The photocurable relief image printing element according to claim 2, wherein the additive comprises tris(nonylphenyl)phosphite.

### Claim 4

A relief image printing element produced from a photocurable printing blank, wherein the photocurable printing blank comprises:
a) a support layer;
b) one or more photocurable layers disposed on the support layer, wherein the one or more photocurable layers comprise:
i) a binder;
ii) one or more monomers;
iii) a photoinitiator; and
iv) an additive selected from the group consisting of phosphites, phosphines, thioether amine compounds, and combinations of one or more of the foregoing; and
v) an antioxidant selected from the group consisting of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, alkylated phenols, alkylated bis-phenols, polymerized trimethyldihydroquinone, dilauryl thiopropionate, and combinations of one or more of the foregoing;
c) a laser ablatable masking layer disposed on the one or more photocurable layers, the laser ablatable masking layer comprising a radiation opaque material; and
d) optionally, a removable coversheet;
wherein the relief image printing element comprises a plurality of relief printing dots which relief printing dots comprise at least one of the following characteristics;
(i) edge sharpness of the relief printing dots, defined as the ratio of the radius of curvature re at the intersection of a shoulder and the top of the relief printing dot to the width of the dot's top printing surface p is less than 5%; or
(ii) average shoulder angle, measured as the angle between a shoulder of the dot across the width of the dot's top printing surface, is less than 30°.

### Claim 5 (depends on 1)

The photocurable relief image printing element according to claim 1, wherein the additive is a thioether amine compound selected from the group consisting of 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 4-[[4,6-bis(nonylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octadecylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-bis(2-methylnonan-2-yl)phenol, 4-[[4,6-bis(hexylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(heptylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2-tert-butyl-6-methylphenol, 4-[[4,6-bis(ethylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(2,4,4-trimethylpentan-2-ylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(2-octylsulfanylethylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-dibutylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-dimethylphenol, 2,6-ditert-butyl-4-[[4-(3,5-ditert-butyl-4-hydroxyanilino)-6-octylsulfanyl-1,3,5-triazin-2-yl]amino]phenol, 4-[[4,6-bis(pentylsulfanyl)-1,3,5-triazin-2-yl]amino-2,6-dimethylphenol, 4-[[4,6-bis(hexylsulfanyl)-1,3,5-triazin-2-yl]amino]-2-tert-butylphenol, 2,6-ditert-butyl-4-[(4-octylsulfanyl-1,3,5-triazin-2-yl)amino]phenol, 4-[[4,6-bis(ethylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-dimethylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]-butylamino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]-cyclohexylamino]-2,6-ditert-butylphenol, 2-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-6-tert-butylphenol, 2-tert-butyl-6-methyl-4-[[4-octylsulfanyl-6-[(2,2,6,6,-tetramethylpiperidin-4-yl)amino]-1,3,5-triazin-2-yl]amino]phenol, 4-[[4,6-bis(octylsulfanylmethyl)-1,3,5-triazin-2-yl)amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl)methylamino]-2,6-ditert-butylphenol, 4-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-2,6-ditert-butylphenol, and 4-[(4-cyclohexyl-6-cyclohexylsulfanyl-1,3,5-triazin-2-yl)amino]-2,6-di(propan-2-yl)phenol.

### Claim 6 (depends on 5)

The photocurable relief image printing element according to claim 5, wherein the additive comprises 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol.

### Claim 7 (depends on 1)

The photocurable relief image printing element according to claim 1, wherein the one or more photocurable layers comprise an antioxidant selected from the group consisting of 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene, butylated hydroxytoluene, polymerized trimethyldihydroquinone, dilauryl thiopropionate, and combinations of one or more of the foregoing.

### Claim 8 (depends on 7)

The photocurable relief image printing element according to claim 7, wherein the antioxidant comprises 1,3,5-trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene.

### Claim 9 (depends on 1)

The photocurable relief image printing element according to claim 1, wherein the one or more photocurable layers comprise one or more materials selected from the group consisting of plasticizers, antiozonants, fillers, reinforcing agents, thermal polymerization inhibitors, UV absorbers and combinations of one or more of the foregoing.

### Claim 10 (depends on 9)

The photocurable relief image printing element according to claim 9, wherein the one or more materials comprise a plasticizer.

### Claim 11 (depends on 1)

The photocurable relief image printing element according to claim 1, wherein the photocurable relief image printing element has a Shore A hardness of between 45 and 70.

### Claim 12 (depends on 11)

The photocurable relief image printing element according to claim 11, wherein the photocurable relief image printing element has a Shore A hardness of between 50 and 65.

### Claim 13 (depends on 4)

The photocurable relief image printing element according to claim 4, wherein the additive is a phosphine selected from the group consisting of triphenyl phosphine, tri-p-tolylphosphine, diphenylmethylphosphine, diphenylethylphosphine, diphenylpropylphosphine, dimethylphenylphosphine, diethylphenylphosphine, dipropylphenylphosphine, divinylphenylphosphine, divinyl-p-methoxyphenylphosphine, divinyl-p-bromophenylphosphine, divinyl-p-tolylphosphine, diallylphenylphosphine, divinyl-p-bromophenylphosphine, and diallyl-p-tolylphosphine and combinations of one or more of the foregoing.

### Claim 14

A photocurable printing blank comprising:
a) a support layer;
b) one or more photocurable layers disposed on the support layer, wherein the one or more photocurable layers comprise:
i) a binder;
ii) one or more monomers;
iii) a photoinitiator; and
iv) an additive, wherein the additive comprises a thioether amine compound, and combinations of one or more of the foregoing;
c) a laser ablatable masking layer disposed on the one or more photocurable layers, the laser ablatable masking layer comprising a radiation opaque material; and
d) optionally, a removable coversheet,
wherein the photocurable printing blank is capable of being selectively crosslinked and cured upon exposure to UV light and then developed to reveal a relief image therein, wherein the relief image comprises a plurality of relief printing dots, and
wherein the presence of the additive in the at least one photocurable layer enhances surface cure of the one or more photocurable layers without requiring a high intensity UV light source, an inert gas chamber, or a laminated membrane.

### Claim 15 (depends on 14)

The photocurable printing blank according to claim 14, wherein the additive further comprises a phosphite selected from the group consisting of tris(nonylphenyl)phosphite, triphenyl phosphite, diphenyl phosphite, tridecyl phosphite, triisodecyl phosphite, tris(tridecyl)phosphite, trilauryl phosphite, disteraryl pentaerythriol diphosphite, diisodecyl phenyl phosphite, diphenyl isodecyl phosphite, diphenyl octyl phosphite, diphenyl isooctyl phosphite, diphenyl tri isodecyl monophenyl dipropyleneglycol diphosphite, alkyl bisphenol A phosphite, tetraphenyl dipropyleneglycol diphosphite, poly(dipropyleneglycol) phenyl phosphite, tris(dipropylene glycol) phosphite, and dioleyl hydrogen phosphite and combinations of one or more of the foregoing.

### Claim 16 (depends on 14)

The photocurable printing blank according to claim 14, wherein the additive further comprises a phosphine selected from the group consisting of triphenyl phosphine, tri-p-tolylphosphine, diphenylmethylphosphine, diphenylethylphosphine, diphenylpropylphosphine, dimethylphenylphosphine, diethylphenylphosphine, dipropylphenylphosphine, divinylphenylphosphine, divinyl-p-methoxyphenylphosphine, divinyl-p-bromophenylphosphine, divinyl-p-tolylphosphine, diallylphenylphosphine, divinyl-p-bromophenylphosphine, and diallyl-p-tolylphosphine and combinations of one or more of the foregoing.

### Claim 17 (depends on 14)

The photocurable printing blank according to claim 14, wherein the thioether amine compound is selected from the group consisting of 2,6-di-tert-butyl-4-(4,6-bis(octylthio)-1,3,5-triazin-2-ylamino)phenol, 4-[[4,6-bis(nonylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octadecylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-bis(2-methylnonan-2-yl)phenol, 4-[[4,6-bis(hexylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(heptylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2-tert-butyl-6-methylphenol, 4-[[4,6-bis(ethylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(2,4,4-trimethylpentan-2-ylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(2-octylsulfanylethylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-dibutylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-dimethylphenol, 2,6-ditert-butyl-4-[[4-(3,5-ditert-butyl-4-hydroxyanilino)-6-octylsulfanyl-1,3,5-triazin-2-yl]amino]phenol, 4-[[4,6-bis(pentylsulfanyl)-1,3,5-triazin-2-yl]amino-2,6-dimethylphenol, 4-[[4,6-bis(hexylsulfanyl)-1,3,5-triazin-2-yl]amino]-2-tert-butylphenol, 2,6-ditert-butyl-4-[(4-octylsulfanyl-1,3,5-triazin-2-yl)amino]phenol, 4-[[4,6-bis(ethylsulfanyl)-1,3,5-triazin-2-yl]amino]-2,6-dimethylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]-butylamino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]-cyclohexylamino]-2,6-ditert-butylphenol, 2-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl]amino]-6-tert-butylphenol, 2-tert-butyl-6-methyl-4-[[4-octylsulfanyl-6-[(2,2,6,6,-tetramethylpiperidin-4-yl)amino]-1,3,5-triazin-2-yl]amino]phenol, 4-[[4,6-bis(octylsulfanylmethyl)-1,3,5-triazin-2-yl)amino]-2,6-ditert-butylphenol, 4-[[4,6-bis(octylsulfanyl)-1,3,5-triazin-2-yl)methylamino]-2,6-ditert-butylphenol, 4-[(4-amino-6-chloro-1,3,5-triazin-2-yl)amino]-2,6-ditert-butylphenol, and 4-[(4-cyclohexyl-6-cyclohexylsulfanyl-1,3,5-triazin-2-yl)amino]-2,6-di(propan-2-yl)phenol.