Radiation-curable compounds
The invention relates to low-viscosity formulations of radiation-curable compounds, to processes for preparing them, to their use, and to inks, printing-inks, and print varnishes that comprise them.
1. A polyurethane composition, comprising:
a polyurethane A,
0.5% to 4% by weight of water, based on an amount of the polyurethane A, and
optionally, a polyfunctional polymerization compound B,
wherein the polyurethane A comprises, in reacted form:
(a) an organic polyisocyanate comprising an allophanate group and having an NCO functionality of at least 2, synthesized from an aliphatic C 4 to C 20 alkylene diisocyanate,
(b) a compound having at least one isocyanate-reactive group and at least one radically polymerizable unsaturated group,
(c) a photoinitiator having at least one isocyanate-reactive group,
(d) optionally, a further diisocyanate, polyisocyanate, or both, which is different from (a),
(e) optionally, a compound having at least two isocyanate-reactive groups, and
(f) optionally, a compound having precisely one isocyanate-reactive group,
wherein the polyurethane composition has a viscosity of not more than 400 Pas, measured according to DIN EN ISO 3219 (shear rate D. 100 s −1 ) at 23° C.
2. The polyurethane composition of claim 1 , wherein the photoinitiator having at least one isocyanate-reactive group (c) is a compound selected from the group consisting of
wherein
R 3 , R 4 , and R 5 each independently of one another are hydrogen, an alkyl group comprising 1 to 4 carbon atoms or an alkyloxy group comprising 1 to 4 carbon atoms,
p is 0 or an integer from 1 to 10,
Y i for i=1 to p independently of one another are selected from the group consisting of —CH 2 —CH 2 —O—, —CH 2 —CH(CH 3 )—O—, —CH(CH 3 )—CH 2 —O—, —CH 2 —C(CH 3 ) 2 —O—, —C(CH 3 ) 2 —CH 2 —O—, —CH 2 —CHVin-O—, —CHVin-CH 2 —O—, —CH 2 —CHPh-O—, and —CHPh-CH 2 —O,
Ph is phenyl, and
Vin is vinyl.
3. The polyurethane composition of claim 1 , wherein the photoinitiator having at least one isocyanate-reactive group (c) is selected from the group consisting of 2-hydroxy-2-methyl-1-phenyl-propan-1-one, 1-hydroxycyclohexyl phenyl ketone, 1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-1-propan-1-one, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)benzyl]phenyl}-2-methylpropan-1-one, 2-hydroxy-1-[4-[hydroxy[4-(2-hydroxy-2-methylpropanoyl)phenyl]methyl]phenyl]-2-methyl-propan-1-one, [4-[3-(4-benzoylphenoxy)-2-hydroxypropoxy]phenyl]phenylmethanone, benzoin, benzoin isobutyl ether, benzoin tetrahydropyranyl ether, benzoin methyl ether, benzoin ethyl ether, benzoin butyl ether, benzoin isopropyl ether, 7H-benzoin methyl ether, 2-hydroxy-2,2-dimethylacetophenone, and 1-hydroxyacetophenone.
4. An ink, printing-ink or print varnish, comprising:
the polyurethane composition of claim 1 ,
the polyfunctional polymerizable compound B,
optionally, a pigment,
optionally, a further photoinitiator, and
optionally, an additive.
5. The ink, printing-ink or print varnish of claim 4 , comprising the further photoinitiator, which is selected from the group consisting of 2,4,6-trimethylbenzoyldiphenylphosphine oxide, ethyl 2,4,6-trimethylbenzoylphenylphosphinate, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2-benzyl-2-dimethylamino-4′-morpholinobutyrophenone, 2-(dimethylamino)-1-(4-morpholinophenyl)-2-(p-tolylmethyl)butan-1-one, 2-hydroxy-1-[4-[[4-(2-hydroxy-2-methylpropanoyl)phenyl]methyl]phenyl]-2-methylpropan-1-one, a polymeric benzophenone derivative, a polymeric thioxanthone derivative, a polymeric α-amino ketone, and a silsesquioxane compound having at least one initiating group.
6. A method of printing on a material selected from the group consisting of polyamide, polyethylene, polypropylene, polyester, polyethylene terephthalate, polystyrene, paper, paperboard, cardboard, plastics-coated paper, plastics-coated paperboard, plastics-coated cardboard, aluminum, and an aluminum-coated polymeric films, comprising contacting the ink, printing-ink or varnish of claim 4 with the material.
7. The method of claim 6 , wherein the material is a food packaging, a cosmetic packaging material, or a pharmaceutical packaging material.
8. The method of claim 6 , further comprising treating the ink, printing-ink or print varnish with actinic radiation.
9. The polyurethane composition of claim 1 , wherein the C 4 to C 20 alklene diisocyanate is hexamethylene diisocyanate.
10. The polyurethane composition of claim 1 , wherein (b) is bonded via allophanate groups to (a).
11. The polyurethane composition of claim 1 , which comprises (d).
12. The polyurethane composition of claim 1 , which comprises (e).
13. The polyurethane composition of claim 1 , which comprises (f).
14. The polyurethane composition of claim 1 , which comprises 0.75% to 4% by weight of water, based on an amount of the polyurethane A.
15. The polyurethane composition of claim 1 , which comprises 1% to 4% by weight of water, based on an amount of the polyurethane A.
16. The polyurethane composition of claim 1 , which comprises 1.25% to 4% by weight of water, based on an amount of the polyurethane A.
17. The polyurethane composition of claim 1 , which comprises 1.5% to 3% by weight of water, based on an amount of the polyurethane A.
18. The composition of claim 1 , which has a viscosity of less than 300 Pas, measured according to DIN EN ISO 3219 (shear rate D, 100 s −1 ) at 23° C.
19. The composition of claim 1 , which has a viscosity of less than 250 Pas, measured according to DIN EN ISO 3219 (shear rate D, 100 s −1 ) at 23° C.
20. The composition of claim 1 , which has a viscosity of less than 200 Pas, measured according to DIN EN ISO 3219 (shear rate D, 100 s −1 ) at 23° C.
21. A method of preparing the polyurethane composition of claim 1 , comprising adding 0.5% to 4% by weight of water to polyurethane A, based on an amount of the polyurethane A.