RADIATIOIN-CURABLE MIXTURE CONTAINING LOW-FUNCTIONALISED, PARTIALLY SAPONIFIED POLYVINYL ACETATE

Abstract

The invention relates to a radiation-curable mixture for generating relief structures, comprising a) at least one functionalized, part-hydrolyzed polyvinyl acetate comprising (i) vinyl alcohol units, (ii) vinyl acetate units, and (iii) vinyl acrylate units, where the vinyl acrylate units, which can be substituted, have the general structure

##STR00001## where R is hydrogen or a linear or branched aliphatic or heteroaliphatic radical having 1 to 12 carbon atoms, or a cycloaliphatic, heterocyclic or aromatic radical having 3 to 12 carbon atoms, as component A, b) at least one initiator as component B, c) at least one ethylenically unsaturated compound different from component A, as component C, d) one or more adjuvants as component D, wherein the amount of vinyl acrylate units (iii) in the functionalized, part-hydrolyzed polyvinyl acetate a), based on all the units (i), (ii), and (iii), is 0.1 to <3 mol %, and component D comprises an additive capable of hydrogen bonding, in an amount of 0.001 to 30 wt %, based on the sum of components A to D.

Claims

1.-14. (canceled)

15. A radiation-curable mixture for generating relief structures, comprising a) at least one functionalized, part-hydrolyzed polyvinyl acetate comprising (i) vinyl alcohol units, (ii) vinyl acetate units, and (iii) vinyl acrylate units, where the vinyl acrylate units, which can be substituted, have the general structure ##STR00003## where R is hydrogen or a linear or branched aliphatic or heteroaliphatic radical having 1 to 12 carbon atoms, or a cycloaliphatic, heterocyclic or aromatic radical having 3 to 12 carbon atoms, as component A, b) at least one initiator as component B, c) at least one ethylenically unsaturated compound different from component A, as component C, d) one or more adjuvants as component D, wherein the amount of vinyl acrylate units (iii) in the functionalized, part-hydrolyzed polyvinyl acetate a), based on all the units (i), (ii), and (iii), is 0.1 to <3 mol %, and component D comprises an additive capable of hydrogen bonding, in an amount of 0.001 to 30 wt %, based on the sum of components A to D.

16. The radiation-curable mixture as claimed in claim 15, wherein the amount of vinyl alcohol units (i) in component A, based on all the units (i), (ii), and (iii), is 65 to 99 mol %.

17. The radiation-curable mixture as claimed in claim 15, wherein the amount of vinyl acetate units (ii) in component A, based on all the units (i), (ii), and (iii), is 5 to 35 mol %.

18. The radiation-curable mixture as claimed in claim 15, wherein component A is present in an amount of 5 to 75 wt %, based on the sum of components A to D.

19. The radiation-curable mixture as claimed in claim 15, wherein component B is present in an amount of 0.1 to 20 wt %, based on the sum of components A to D.

20. The radiation-curable mixture as claimed in claim 15, wherein the ethylenically unsaturated compound of component C comprises at least one vinyl ether group and/or acrylate group and/or methacrylate group.

21. The radiation-curable mixture as claimed in claim 15, wherein component C is present in an amount of 0.5 to 50 wt %, based on the sum of components A to D.

22. The radiation-curable mixture as claimed in claim 15, wherein the additives are selected from the group consisting of plasticizers, solvents, further binders, colorants, stabilizers, chain transfer agents, UV absorbers, dispersing assistants, non-radically crosslinking crosslinkers, viscosity modifiers, and hydrogen bond-accepting additives.

23. The radiation-curable mixture as claimed in claim 15, wherein component D is present in an amount of 1 to 50 wt %, based on the sum of components A to D.

24. The radiation-curable mixture as claimed in claim 15, wherein the additive capable of hydrogen bonding is selected from the group consisting of polyvinyl alcohol, polyvinyl acetate, polyethyleneimine, polyurethanes, polyethylene glycol, and polyvinyl alcohol/polyethylene glycol graft copolymer.

25. A radiation-curable multilayer element at least comprising a relief-foil ling layer of the radiation-curable mixture as claimed in claim 15 on a carrier.

26. The radiation-curable multilayer element as claimed in claim 25, comprising, on or under the relief-forming layer, at least one further layer selected from the group consisting of a protective layer, a release layer, a mask layer, a barrier layer, a layer for generating a surface structure, and a tie layer or any desired combinations thereof.

27. A method for producing the multilayer element having a relief-structure from a radiation-curable multilayer element as claimed in claim 25, comprising irradiating the relief-forming layer through an integral or appliable mask layer and removing the uncured regions of the relief-forming layer.

28. A method for producing the multilayer element having a relief structure from a radiation-curable multilayer element as claimed in claim 25, comprising irradiating the relief-forming layer and engraving a relief into cured regions of the relief-forming layer.

Description

EXAMPLES

Methods

Method for Determining the Degree of Functionalization:

[0144] In a first step, the samples for measurement are purified in order to free them of reaction residues, especially monomer. This is done by purifying around 12 g of sample with 200 g of acetone for 6 h via Soxhlet extraction at 56 C. This is followed by drying under reduced pressure (around 100 mbar) for 2 h at 70 C. A 10% solution of the purified samples in n-propanol/water (w %, n-propanol=50%) is produced, with the exact solids content being recorded. 5 g of this solution are weighed out with 2 g of potassium hydroxide (aq. 2 mol/L) into a 50 mL vessel. The samples are placed in a drying cabinet at 93 C. for 4 h and conditioned. For neutralization, 3 g of hydrochloric acid (2 mol/L) are weighed in. The samples are subsequently shaken for 45 min on an IKA 130 basic shaker (IKA) at 450 rpm. The cap is removed and 35 g of acetone with decanol as internal standard (1500 g acetone/0.51 g 1-decanol) are weighed in. The samples are mixed for 1.5 h on an IKA 130 basic shaker (IKA) at 450 rpm. This solution is dispensed via a 0.25 m syringe filter into 2 mL GC vials for liquid injection. These vials are placed in the autosampler and analyzed with a TRACE 1300 GC with TriPlus 100LS gas chromatograph (Thermo Fisher Scientific) using the Chromeleon software (Version 7.2.), the output taking place in terms of methacrylic acid (MAA) and acetic acid (acetic) in mg/g. This is done using an FFAP column (Chromatographie Service GmbH) with a length of 50 m, an occupancy of 0.25 mm at 220 C. and 175 kPa, an FID detector, and hydrogen (6.0, Air Liquide) as carrier gas.

[0145] The results are evaluated on the assumption that the molar amount of the optionally substituted acrylic acid and the acetic acid corresponds to the molar amounts of the vinyl acrylate and vinyl acetate units, respectively, that are present in the polymer, and that the molar fractions of vinyl alcohol, vinyl acrylate and/or vinyl acetate units add up to 100%. This is illustrated below using vinyl methacrylate as an example. The values of the methacrylic acid (mg/g) and of the acetic acid (mg/g) from the GC analysis are converted for the overall solution of the functional polymer weighed in (in g), with the masses m.sub.MAA and m.sub.acetic being obtained in g. The molar masses are calculated as follows:

[00001]$n_{\mathrm{MAA}}=\frac{m_{\mathrm{MAA}}}{M_{\mathrm{MAA}}}.Math..Math.\mathrm{and}.Math..Math.n_{\mathrm{acetic}}=\frac{m_{\mathrm{acetic}}}{M_{\mathrm{acetic}}}.Math..Math.\mathrm{and}.Math..Math.\mathrm{therefore}$$n_{\mathrm{vinyl}.Math..Math.\mathrm{alcohol}}=\frac{\begin{array}{c}(m_{\mathrm{fumct}.Math.\mathrm{PVA}}-\left(n_{\mathrm{vinyl}.Math..Math.\mathrm{acetate}}{M}_{\mathrm{vinyl}.Math..Math.\mathrm{acetate}}\right)-\\ \left(n_{\mathrm{vinyl}.Math..Math.\mathrm{methacrylate}}{M}_{\mathrm{vinyl}.Math..Math.\mathrm{methacrylate}}\right)\end{array}}{M_{\mathrm{vinyl}.Math..Math.\mathrm{alcohol}}}$$\mathrm{where}.Math..Math.M_{\mathrm{vinyl}.Math..Math.\mathrm{acetate}}=86.Math..Math.\frac{g}{\mathrm{mol}}.Math..Math.M_{\mathrm{vinyl}.Math..Math.\mathrm{methacrylate}}=112.Math..Math.\frac{g}{\mathrm{mol}}$$M_{\mathrm{vinyl}.Math..Math.\mathrm{alcohol}}=44.Math..Math.\frac{g}{\mathrm{mol}}$

[0146] thus giving, for the degree of functionalization in %:

[00002]$\mathrm{Degree}.Math..Math.\mathrm{of}.Math..Math.\mathrm{functionalization}.Math.\left[\%\right]=\frac{n_{\mathrm{vinyl}.Math..Math.\mathrm{methacrylate}}100}{n_{\mathrm{vinyl}.Math..Math.\mathrm{methacrylate}}+n_{\mathrm{vinyl}.Math..Math.\mathrm{acetate}}+n_{\mathrm{vinyl}.Math..Math.\mathrm{alcohol}}}$

Stress-Strain Measurements.

[0147] The stress-strain measurements are carried out on exposed, washed, and dried samples (without cover foil and carrier foil, which have been peeled off beforehand), using the total thickness of the plate (that is, the exposure is carried out from the facing side without structuring). The exposure, washout, and drying conditions are reported in the respective tests. After drying, the plates were stored at room temperature overnight and four samples each, with a measurement length of 20 mm and a measurement width of 4 mm, were punched out using a Zwick specimen form 5A (from Zwick Roell AG). It should be ensured here that there are no instances of damage (cracks etc.) and/or foreign bodies (e.g., air bubbles, particles, etc.) present in the samples. The measurements were carried out using a Zwick Roell 72.5 instrument (from Zwick Roell AG) and the testexpert software version V10.0, in a method based on DIN 53504, with a pre-tensioning force of 0.01 MPa and a strain rate of 100 mm/min at room temperature. 4 samples are measured in each case, and the arithmetic means of the elongation at break ER in % and also of the yield stress .sub.max in N/mm.sup.2 are reported.

Viscosity Measurements for the Part-Hydrolyzed Polyvinyl Acetates

[0148] Measurements of the viscosity took place using a falling-ball viscometer according to DIN 53 015 on a 4% aqueous solution at 20 C.

Viscosity Measurement for the Radiation-Sensitive Mixtures

[0149] The viscosity measurements took place using a HAAKE Viscotester 550 rotational viscometer with MV measuring cup according to DIN 53019 at 60 C. with a rotary speed of 64 revolutions/min.

Determination of Exposure Time

[0150] To determine the exposure time, plates had their protective foil removed and were then exposed for different times using a Nyloprint Combi CW 3550 (Flint Group), equipped with TL 09 tubes, and through a test negative (Reprofilm, Kstlin, 1C Testform nyloprint conventional, 2540 dpi, 45 angle). After washout with a Nyloprint Combi CW 3550 (Flint Group) using water, and after subsequent drying at 65 C. for 10 minutes, a determination was made of the exposure time for which the 2% halftone screen (59 L/cm) is reproduced without error.

Determination of Washout Time

[0151] For determination of the washout time, unexposed plates were washed using water in a Nyloprint Combi CW 3550 (Flint Group) until the photosensitive layer was completely removed. The time required to achieve this is reported as the washout time in minutes.

Drying

[0152] The washed plates were dried at 65 C. for 10 minutes in a Nyloprint Combi CW 3550 (Flint Group) dryer.

Curling Measurements

[0153] For determination of the curling, plates measuring 2020 cm had their protective layer removed and were then exposed using a Nyloprint Combi CW 3550 (Flint Group), equipped with TL 09 tubes, for the corresponding time to form the 2% halftone screen (59 L/cm) in minutes (without negative) and developed (corresponding washout time with water for the particular plate) and dried. The plates were subsequently stored at room temperature for 3 days. During this time, the 4 corners of the plates curled upward away from the substrate. At the 2 corners with the highest values, the distance of the corner from the substrate, in millimeters, was measured, and the arithmetic mean of these 2 measurement values was formed and reported.

Evaluation the Printing Results in Relation to the Highlights

[0154] Additionally, a printing test was carried out using a UV letterpress ink, UVONOVA (Flint Group). For this test, the printing plates were stretched onto a printing cylinder and printed on a conventional letterpress unit (printing machine: Nilpeter-F 2400). The print substrate was High Gloss White Premium paper with one-side coating from Avery Dennison. The printing speed was 25 m/min. The size of the halftone screen was 59 lines/cm. Measurements were made of the tonal value gain (1% to 10% halftone field) of the characteristic print lines in relation to the ideal tonal value original (1:1 curve). The results of the printing test are compiled in Table 4-5 and 6. After printing, the printing plates were inspected for cracks in the solid areas.

Example 1: Preparation of Polymer P1 with 1.0 Mol % Functionalization

[0155] In a vessel, with thorough mixing by means of a powerful stirrer, 82.5 parts by weight of polyvinyl acetate pellets (degree of hydrolysis 82%, viscosity: 5 mPas) were admixed with a mixture of 6.6 parts by weight of propylene carbonate, 6.6 parts by weight of ethylene carbonate, 3.3 parts by weight of methacrylic anhydride (VISIOMER MAAH, Evonik Industries, 94% grade), 0.9 part by weight of an esterification catalyst (N-methylimidazole) and 0.1 part by weight of 2,6-di-t-butylcresol as a thermal stabilizer (Kerobit TBK from BASF, Germany). The mixture is subsequently stirred at a temperature of 85 C. for 5 hours. After this time, free-flowing pellets are obtained which consist of a part-hydrolyzed, subsequently polymer-analogously functionalized polyvinyl acetate, the swelling agents, catalyst, stabilizer, and methacrylic acid.

[0156] In accordance with the method described above (in analogy to EP0962828A1), a copolymer with 1.0 mol % vinylmethacrylic acid units, 84.8 mol % vinyl alcohol units and 14.2 mol % vinyl acetate units was obtained.

Example 2: Preparation of Polymer P2 with 1.1 Mol % Functionalization

[0157] In analogy to Example 1, a copolymer was prepared, starting from a part-hydrolyzed polyvinyl acetate having a degree of hydrolysis of 88% and a viscosity of 3 mPas. The result obtained was a copolymer with 1.1 mol % vinylmethacrylic acid units, 86.2 mol % vinyl alcohol units and 12.7 mol % vinyl acetate units.

Example 3: Preparation of Polymer P3 with 1.9 Mol % Functionalization

[0158] In analogy to Example 1, starting from a part-hydrolyzed polyvinyl acetate (degree of hydrolysis of 82%, viscosity of 5 mPas) a copolymer was obtained with 1.9 mol % vinylmethacrylic acid units, 83.9 mol % vinyl alcohol units and 14.2 mol % vinyl acetate units.

Example 4; Preparation of Polymer P4 with 0.57 Mol % Functionalization

[0159] In analogy to Example 1, starting from a part-hydrolyzed polyvinyl acetate (degree of hydrolysis of 82%, viscosity of 5 mPas) a copolymer was obtained with 0.57 mol % vinylmethacrylic acid units, 82.4 mol % vinyl alcohol units and 17.03 mol % vinyl acetate units.

Comparative Example 5: Preparation of Polymer P5 with 3.4 Mol % Functionalization

[0160] The functionalized polyvinyl acetate was prepared in accordance with DE-A 33 22 994. For this purpose, 50 parts by weight of a part-hydrolyzed polyvinyl acetate (degree of hydrolysis 82 mol %, average molecular weight 30 000 g/mol) were suspended in 150 parts by weight of toluene and then admixed with 8 parts by weight of methyacrylic anhydride, 0.4 part by weight of methylimidazole and 0.05 part by weight of Kerobit TBK. The inhomogeneous reaction mixture was stirred at 85 C. for 5 h, after which the reaction product was separated off, washed with toluene and dried at 50 C. for 12 hours in a drying cabinet. This gave a copolymer with 3.4 mol % vinyl(meth)acrylic acid units, 81.0 mol % vinyl alcohol units and 15.6 mol % vinyl acetate units.

TABLE-US-00001 TABLE 1 Overview of the part-hydrolyzed functionalized polyvinyl acetates P1 to P4 Compar- Exam- Exam- Exam- Exam- ative ple 1 ple 2 ple 3 ple 4 example P1 P2 P3 P4 P5 Vinyl(meth)acrylic 1.0 1.1 1.9 0.57 3.4 acid units Vinyl alcohol units 84.8 86.2 83.9 82.4 81.0 (mol %) Vinyl acetate units 14.2 12.7 14.2 17.03 15.6 (mol %)

Printing Plate Precursors:

[0161] To produce photopolymerizable printing plates, the following procedure is performed with the copolymers obtained as per examples 1 to 5 and with the other constituents:

[0162] Corresponding parts by weight (see following examples) of a part-hydrolyzed, subsequently polymer-analogously functionalized polyvinyl acetate (described in examples 1 to 5) and of a polyvinyl alcohol/polyethylene glycol graft copolymer, obtainable by grafting vinyl acetate onto polyethylene glycol with molecular weights of between 1000 and 50 000 and subsequently hydrolyzing to a degree of hydrolysis of between 80 and 100% (described for example in DE 2846647A1), were dissolved in a mixture of 276 parts by weight of water and 184 parts by weight of n-propanol at a temperature of 85 C. and the solution was stirred until it was homogeneous. Subsequently, as ethylenically unsaturated compound, corresponding parts by weight of a phenyl glycidyl ether acrylate (2-hydroxy-3-phenoxypropyl acrylate) and, as initiator, 1.5 parts by weight of benzil dimethyl ketal, as thermal inhibitor 0.3 part by weight of the potassium salt of N-nitrosocyclohexalhydroxylamine, and also, as dye, 0.01 part by weight of safranin T (C.I. 50240) and 0.01 part by weight of acriflavin (C.I. 46000) were added and the solution was stirred at a temperature of 85 C. until it was homogeneous. This solution was then cast onto a foil carrier so as to give a light-sensitive layer 600 m thick after drying. This material was laminated onto a coated PET foil, and the resulting layer, with a total thickness of 1050 m, was dried in a drying cabinet at 60 C. for three hours.

[0163] The conventional production of printing plates takes place using a photographic negative. For this purpose, the protective foil is first peeled away from the printing plate, after which the photosensitive layer is exposed through a test negative in a UV vacuum exposure unit (Nyloprint Combi CW 3550, Flint Group) and washed out with water (see Determination of washout time), dried, and aftertreated.

Example 6: Mixture Comprising Polymer P1 with 1.0 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

[0164] A photopolymerizable formulation consisting of:

[0165] 45 parts by weight of the functionalized copolymer P1 prepared in example 1,

[0166] 20 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0167] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0168] 1.5 parts by weight of benzil dimethyl ketal,

[0169] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt, 0.01 part by weight of safranin T (C.I. 50240),

[0170] 0.01 part by weight of acriflavin (C.I. 46000),

[0171] was produced as described above and processed into a print precursor. The measured viscosity on application was 3500 mPas (60 C.).

Example 7: Mixture Comprising Polymer P1 with 1.0 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

[0172] A photopolymerizable formulation consisting of:

[0173] 45 parts by weight of the functionalized copolymer P1 prepared in example 1,

[0174] 20 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 86% and a viscosity of 4 mPas

[0175] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0176] 1.5 parts by weight of benzil dimethyl ketal,

[0177] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0178] 0.01 part by weight of safranin T (C.I. 50240),

[0179] 0.01 part by weight of acriflavin (C.I. 46000),

[0180] was produced as described above and processed into a print precursor.

Example 8: Mixture Comprising Polymer P2 with 1.1 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

[0181] A photopolymerizable formulation consisting of:

[0182] 55 parts by weight of the functionalized copolymer P2 prepared in example 2,

[0183] 10 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 86% and a viscosity of 4 mPas

[0184] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0185] 1.5 parts by weight of benzil dimethyl ketal,

[0186] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0187] 0.01 part by weight of safranin T (C.I. 50240),

[0188] 0.01 part by weight of acriflavin (C.I. 46000),

[0189] was produced as described above and processed into a print precursor.

Example 9: Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

[0190] A photopolymerizable formulation consisting of:

[0191] 45 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0192] 20 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0193] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0194] 1.5 parts by weight of benzil dimethyl ketal,

[0195] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0196] 0.01 part by weight of safranin T (C.I. 50240),

[0197] 0.01 part by weight of acriflavin (C.I. 46000),

[0198] was produced as described above and processed into a print precursor. The measured viscosity on application was 4770 mPas (60 C.).

Example 10; Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyamine)

[0199] A photopolymerizable formulation consisting of:

[0200] 45.17 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0201] 17.5 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0202] 2.5 parts by weight of a polyethyleneimine (polyamine) having a molecular weight of (GPC) around 25 000 g/mol, a viscosity (50 C., DIN 53015) of around 15 500 mPas and a pH of around 13,

[0203] 33 parts by weight of phenyl glycidyl ether acrylate,

[0204] 1.5 parts by weight of benzil dimethyl ketal,

[0205] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0206] 0.01 part by weight of orasol blue (C.I. Solvent Blue 70),

[0207] 0.02 part by weight of acriflavin (C.I. 46000),

[0208] was produced as described above and processed into a print precursor. The measured viscosity on application was 4310 mPas (60 C.).

Example 11: Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyamine)

[0209] A photopolymerizable formulation consisting of:

[0210] 45.17 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0211] 17.5 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0212] 2.5 parts by weight of a 50% aqueous solution of a polyethyleneimine (polyamine, cationic) having a viscosity (20 C., ISO 2431, No. 4) of around 100 mPas and a pH of around 11,

[0213] 33 parts by weight of phenyl glycidyl ether acrylate,

[0214] 1.5 parts by weight of benzil dimethyl ketal,

[0215] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0216] 0.01 part by weight of orasol blue (C.I. Solvent Blue 70),

[0217] 0.02 part by weight of acriflavin (C.I. 46000),

[0218] was produced as described above and processed into a print precursor. The measured viscosity on application was 3920 mPas (60 C.).

Example 12: Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyurethane)

[0219] A photopolymerizable formulation consisting of:

[0220] 43 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0221] 20 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0222] 2.0 parts by weight of a polyurethane acrylate PUA BIN 200 (BASF)

[0223] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0224] 1.5 parts by weight of benzil dimethyl ketal,

[0225] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0226] 0.01 part by weight of safranin T (C.I. 50240),

[0227] 0.01 part by weight of acriflavin (C.I. 46000),

[0228] was produced as described above and processed into a print precursor. The measured viscosity on application was 4670 mPas (60 C.).

Example 13: Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol)

[0229] A photopolymerizable formulation consisting of:

[0230] 45 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0231] 20 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0232] 6.5 parts by weight of glycerol,

[0233] 33.17 parts by weight of phenyl glycidyl ether acrylate,

[0234] 1.5 parts by weight of benzil dimethyl ketal,

[0235] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0236] 0.02 part by weight of orasol blue (C.I. Solvent Blue 70),

[0237] 0.01 part by weight of acriflavin (C.I. 46000),

[0238] was produced as described above and processed into a print precursor. The measured viscosity on application was 3990 mPas (60 C.).

Example 14: Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyether)

[0239] A photopolymerizable formulation consisting of:

[0240] 45 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0241] 20 parts by weight of a PEG 400 polymer (polyethylene glycol),

[0242] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0243] 1.5 parts by weight of benzil dimethyl ketal,

[0244] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0245] 0.01 part by weight of safranin T (C.I. 50240),

[0246] 0.01 part by weight of acriflavin (C.I. 46000),

[0247] was produced as described above and processed into a print precursor. The measured viscosity on application was 4340 mPas (60 C.).

Example 15 Mixture Comprising Polymer P5 with 3.4 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

[0248] A photopolymerizable formulation consisting of:

[0249] 45 parts by weight of the functionalized copolymer P5 prepared in example 5,

[0250] 20 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0251] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0252] 1.5 parts by weight of benzil dimethyl ketal,

[0253] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0254] 0.01 part by weight of safranin T (C.I. 50240),

[0255] 0.01 part by weight of acriflavin (C.I. 46000),

[0256] was produced as described above and processed into a print precursor.

Comparative Example 16: Mixture Comprising Polymer P5 with 3.4 Mol % Functionalization with Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

[0257] A photopolymerizable formulation consisting of:

[0258] 24 parts by weight of the functionalized copolymer P5 prepared in example 5,

[0259] 24 parts by weight of a polyvinyl alcohol/polyethylene glycol graft copolymer having a degree of hydrolysis of 97% and a viscosity of 5 mPas

[0260] 21.84 parts by weight of part-hydrolyzed polyvinyl acetate (degree of hydrolysis 88%, viscosity of 3 mPas),

[0261] 28 parts by weight of phenyl glycidyl ether acrylate,

[0262] 1.5 parts by weight of benzil dimethyl ketal,

[0263] 0.4 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0264] 0.01 part by weight of safranin T (C.I. 50240),

[0265] 0.25 part by weight of BYK 370 (BYK-Chemie GmbH),

[0266] was produced as described above and processed into a print precursor. The measured viscosity on application was 7500 mPas (60 C.).

Examples without Hydrogen Bond-Forming Additive (Polyol/Polyether Graft Copolymer)

Example 17. Mixture Comprising Polymer P1 with 1.0 Mol % Functionalization

[0267] A photopolymerizable formulation consisting of:

[0268] 65 parts by weight of the functionalized copolymer P1 prepared in example 1,

[0269] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0270] 1.5 parts by weight of benzil dimethyl ketal,

[0271] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0272] 0.01 part by weight of safranin T (C.I. 50240),

[0273] 0.01 part by weight of acriflavin (C.I. 46000),

[0274] was produced as described above and processed into a print precursor.

Example 18: Mixture Comprising Polymer P3 with 1.9 Mol % Functionalization

[0275] A photopolymerizable formulation consisting of:

[0276] 65 parts by weight of the functionalized copolymer P3 prepared in example 3,

[0277] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0278] 1.5 parts by weight of benzil dimethyl ketal,

[0279] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0280] 0.01 part by weight of safranin T (C.I. 50240),

[0281] 0.01 part by weight of acriflavin (C.I. 46000),

[0282] was produced as described above and processed into a print precursor.

Comparative Example 19: Mixture Comprising Polymer P5 with 3.4 Mol % Functionalization

[0283] A photopolymerizable formulation consisting of:

[0284] 65 parts by weight of the functionalized copolymer P5 prepared in example 5,

[0285] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0286] 1.5 parts by weight of benzil dimethyl ketal,

[0287] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0288] 0.01 part by weight of safranin T (C.I. 50240),

[0289] 0.01 part by weight of acriflavin (C.I. 46000),

[0290] was produced as described above and processed into a print precursor,

Example 20: Mixture Comprising Polyvinyl Alcohol without Functionalization

[0291] A photopolymerizable formulation consisting of:

[0292] 65 parts by weight of part-hydrolyzed polyvinyl acetate (degree of hydrolysis 82%, viscosity 5 mPas),

[0293] 33.18 parts by weight of phenyl glycidyl ether acrylate,

[0294] 1.5 parts by weight of benzil dimethyl ketal,

[0295] 0.3 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt,

[0296] 0.01 part by weight of safranin T (C.I. 50240),

[0297] 0.01 part by weight of acriflavin (C.I. 46000),

[0298] was produced as described above and processed into a print precursor.

TABLE-US-00002 TABLE 2a Photopolymerizable formulations with hydrogen bond-forming additive, standardized to comparative example 16 Comparative Comparative Example 6 Example 7 Example 8 Example 9 example 15 example 16 Vinyl(meth)acrylic 1.0 1.0 1.1 1.9 3.4 3.4 acid units (mol %) Vinyl alcohol units 84.8 84.8 86.2 83.9 81.0 81.0 (mol %) Vinyl acetate units 14.2 14.2 12.7 14.2 15.6 15.6 (mol %) Graft copolymer 20 20 10 20 20 24 additive (wt %) Additive polyol polyol polyol polyol polyol polyol Curling * 0.42 0.5 0.64 0.13 1.10 1.00 Exposure time * 1.00 0.86 1.43 0.86 0.86 1.00 Washing time * 0.88 1.00 0.63 0.88 1.00 1.00 Quality after good good satis. very good good good washing Well depth * 1.29 1.19 1.00 1.52 1.38 1.00 Printing behavior good good very good satis. satis. .sub.max * 0.41 0.46 0.51 0.74 1.00 R * 1.70 1.80 1.19 0.81 1.00 * standardized to comparative example 16

[0299] As is evident from Table 2a, all of examples 6 to 9 exhibit relatively low curling, unchanged or lower exposure and washing times, greater well depths, better printing behavior, lower yield stress and hence higher elasticity and higher tensile strength.

TABLE-US-00003 TABLE 2b Photopolymerizable formulations with hydrogen bond-forming additive, standardized to comparative example 16 Comparative Example 10 Example 11 Example 12 Example 13 Example 14 example 16 Vinyl(meth)acrylic 1.9 1.9 1.9 1.9 1.9 3.4 acid units (mol %) Vinyl alcohol units 83.9 83.9 83.9 83.9 83.9 81.0 (mol %) Vinyl acetate units 14.2 14.2 14.2 14.2 14.2 15.6 (mol %) Total additives 20 20 22 26.5 20 24 (wt %) Additive polyamine, polyamine, polyol, polyol polyol polyol polyol polyol polyamide Curling * 0.25 0.22 0.21 0.13 0.17 1.00 Exposure time * 1.00 1.14 1.14 1.43 1.00 1.00 Washing time * 1.00 1.25 1.13 0.75 1.00 1.00 Quality after good good good good satis. good washing Well depth * 1.04 0.93 1.13 1.28 1.41 1.00 Printing behavior good good good good satis. satis. .sub.max * 0.34 0.50 1.00 R * 0.81 1.02 1.00 * standardized to comparative example 16

[0300] As is evident from Table 2b, all of examples 10 to 14 exhibit relatively low curling, unchanged or lower exposure and washing times, greater well depths, better printing behavior, lower yield stress and hence higher elasticity and higher tensile strength.

TABLE-US-00004 TABLE 3 Photopolymerizable formulation without hydrogen bond-forming additive, standardized to comparative example 16 Compar- Compar- Compar- ative ative ative Exam- Exam- example example example ple 17 ple 18 19 20 16 Vinyl(meth)acryl- 1.0 1.9 3.4 0 3.4 ic acid units (mol %) Vinyl alcohol 84.8 83.9 81.0 18.0 81.0 units (mol %) Vinyl acetate 14.2 14.2 15.6 82.0 15.6 units (mol %) Curling * 0.29 0.14 1.18 nm 1.00 Exposure time * 0.86 1.00 1.14 >1.43.sup. 1.00 Washing time * 1.38 1.50 1.63 0.88 1.00 Quality after good good satis. very good washing poor Well depth * 1.45 1.17 1.36 nm 1.00 Printing behavior good good satis. nm satis. .sub.max * 0.72 0.52 1.21 0.4 1.00 R * 0.97 0.80 0.61 1.95 1.00 * standardized to comparative example 16 nm = not measurable .sup.no stable halftone field/screen is formed

[0301] As is evident from Table 3, all of examples 17 and 18 exhibit relatively low curling, unchanged or lower exposure and washing times, greater well depths, better printing behavior, lower yield stress and hence higher elasticity and higher tensile strength. Only comparative example 20, without functionalization, shows no stably formed halftone field (ablated by the brushes during washout) and therefore does not allow further data to be measured either.

TABLE-US-00005 TABLE 4 Direct comparison of the photopolymerizable formulations with and without hydrogen bond-forming additive Exam- Exam- Exam- Exam- Exam- ple 6 ple 7 ple 17 ple 9 ple 18 Funct. PVA P1 P1 P1 P3 P3 Hydrogen bond polyether, polyether, polyether, additive polyol polyol polyol Curling * 0.42 0.5 0.29 0.13 0.14 Exposure 1.00 0.86 0.86 0.86 1.00 time * Washing time * 0.88 1.00 1.38 0.88 1.50 Quality after good good good very good washing good Well depth * 1.29 1.19 1.45 1.52 1.17 Printing good good good very good behavior good Cracking crack- little moderate crack- little free free .sub.max * 0.41 0.46 0.72 0.51 0.52 R * 1.70 1.80 0.97 1.19 0.80 * standardized to comparative example 16

[0302] A comparison of the results (Table 4) of the formulations with P1 from examples 6 and 7 (with hydrogen bond-forming additive) with example 17 (without additive), and of formulations of example 9 with example 18 (without additive), shows that the addition of hydrogen bond-forming additive results in a shorter washout time, less cracking during printing, lower yield stress and hence higher elasticity and also a higher tensile strength.

TABLE-US-00006 TABLE 5 Measured tonal values (printing results) of analog plates of examples 6 to 16 Compar- Exam- Exam- Exam- Exam- ative TV ple 6 ple 7 ple 9 ple 15 example original (P1) (P1) (P3) (P5) 16 (P5) 1.00% 1.5% 7.0% 14.2% 2.00% 4.5% 3.2% 9.2% 8.5% 19.6% 3.00% 8% 5.1% 9.3% .sup.10% 23.4% 4.00% 13.2% .sup.7% 9.9% 11.9% 23.4% 5.00% 16.5% 9.3% 11.4% 12.6% 26.5% 10.00% 22.3% 17.7% 19.0% 21.3% 30.6%

[0303] Table 5 shows that in particular the low tonal values are better maintained and the deviations relative to the target value are smaller.

Example 21: Digital Plates

[0304] Digital photopolymerizable printing plates are produced with polymers from examples 1 to 5 and photopolymerizable formulations produced from them, of examples 6 to 16, but with the application of a laser-ablatable mask layer, which was obtained from a suspension consisting of 2 parts of carbon black (Printex U from Orion Engineered Carbons GmbH) and 8 parts of a part-hydrolyzed polyvinyl acetate (KP 5-88 from Kuraray) in 80 parts of water and 20 parts of n-propanol.

[0305] The plates were mounted onto the drum of an IR laser (ESKO CDI Spark 2530) and laser-treated. The laser-treated motif corresponded to the test negative from the preceding examples. Exposure then took place in a UV vacuum exposure unit (Nyloprint Combi CW 3550, Flint Group) and was followed by washout with water, drying, and aftertreatment.

[0306] Ultimately, the digital plates with laser-ablatable mask layer behaved similarly to the conventional plates and, in comparison to the comparative formulations, exhibited significant improvements (higher resolution, reduced curling, unchanged or lower exposure and washing times, higher well depths, better printing behavior, higher elasticity, and higher tensile strength).

TABLE-US-00007 TABLE 6 Measured tonal values (printing results) of digital plates of examples 6, 9 and 16 Tonal Compar- value Exam- Exam- ative original ple 6 ple 9 example 16 1.00% 2.4% 2.4% 2.4% 2.00% 4.0% 3.9% 5.5% 3.00% 6.1% 4.7% 6.9% 4.00% 7.6% 6.2% 7.0% 5.00% 9.8% 8.4% 9.2% 10.00% 20.0% 15.5% 15.5%

[0307] Table 6 shows that in particular the low tonal values are better maintained and the deviations relative to the target value are smaller.

Example 22: Laser Engraving

[0308] Plates according to example 3, functionalized PVA from KP 5-82 with 1.9 mol % functionalization, were produced as described above and processed to give a print precursor.

[0309] A photopolymerizable formulation consisting of:

[0310] 58.78 parts by weight of the functionalized copolymer P3 prepared in example 3

[0311] 33.4 parts by weight of glycerol dimethacrylate

[0312] 5.2 parts by weight of finely ground quartz with an average grain size of 3 m

[0313] 2.0 parts by weight of benzil dimethyl ketal

[0314] 0.6 part by weight of N-nitrosocyclohexylhydroxylamine, potassium salt

[0315] 0.01 part by weight of safranin T (C.I. 50240).

[0316] 0.01 part by weight of acriflavin (C.I. 46000).

[0317] UV exposure took place for 2.5 minutes using a nyloprint combi CW 3550 exposure unit. The plates were then mounted onto the drum of a CO.sub.2 laser (Agrios, Stork Prints Austria GmbH) and laser-treated with a resolution of 2032 dpi. The laser-treated motif included various halftone wedges, with the resolution of the halftone screen selected being 60 L/cm. The surface coverage was varied from 70 to 90%. Surface coverage in pad printing refers to the percentage area removed by engraving, in comparison to the total area.

[0318] The power of the laser was 500 watts. The optimum distinctness of image was achieved at a rotary speed of 250 revolutions per minute.

[0319] The engraved plates were subsequently mounted on a pad printing machine (Morlock, closed blade pot), The pad printing ink used was a solvent-based pad printing ink, Marabu TPY980 (white). The ink contains hydrocarbons, ketones, and acetates as solvents. The curing agent added was 10% isocyanate curing agent H1 from Marabu. On printing onto the printing body, it was possible with all of the plates to image fine elements up to a surface coverage of 90%.