Coating composition, (meth)acrylic polymer and monomer mixture for producing the (meth)acrylic polymer
The present invention relates to a coating composition comprising at least one photo-initiator and at least one (meth)acryl-polymer having units that are derived from (meth)acryl-monomers that have at least one double bond and 8 to 40 carbon atoms in the alkyl residue. The present invention furthermore relates to a monomer mixture comprising at least one (meth)acryl-monomer having at least one double bond and 8 to 40 carbon atoms in the alkyl residue and at least one photo-initiator monomer and a (meth)acryl-polymer that can be obtained by polymerization of said monomer mixture. The present invention furthermore relates to a method for producing a coating. The present invention furthermore relates to a coated object comprising a coating obtained by said method.
1. A coating composition, comprising:
a photoinitiator; and
a (meth)acrylic polymer comprising, in polymerized form, a (meth)acrylic monomer of formula (IV):
wherein:
R 1 is hydrogen or methyl;
X is oxygen or a group of the formula NR′, wherein R′ is hydrogen or a radical comprising 1 to 6 carbon atoms; and
R 9 is a linear or branched alkyl radical comprising 8 to 40 carbon atoms and a C—C double bond,
wherein a maximum content of (meth)acrylic monomers comprising two or more (meth)acrylate groups, based on a total weight of polymerized monomers in the (meth)acrylate polymer, is 1% by weight, and
wherein the coating composition has a dynamic viscosity in a range from 10 to 500 mPas, measured in accordance with DIN EN ISO 2555 at 25° C.
2. The composition of claim 1 , wherein the photoinitiator is activable by exposure to light having a wavelength in a range from 200 to 800 nm.
3. The composition of claim 1 , wherein the photoinitiator is a compound having a molecular weight of less than 1000 g/mol.
4. The composition of claim 1 , wherein the photoinitiator is a compound having a molecular weight of greater than or equal to 1000 g/mol.
5. The composition of claim 1 , wherein the (meth)acrylic polymer comprises 0.5 to 60% by weight of the (meth)acrylic monomer.
6. The composition of claim 1 , wherein the (meth)acrylic polymer has an iodine number in a range from 1 to 300 g iodine.
7. The composition of claim 1 , wherein the (meth)acrylic polymer has a glass transition temperature in a range from −20 to 40° C.
8. The composition of claim 1 , wherein the (meth)acrylic polymer is an emulsion polymer.
9. The composition of claim 1 , wherein the (meth)acrylic polymer has a swelling factor of at least 2, measured at 20° C. with a tetrahydrofuran/water mixture.
10. The composition of claim 1 , wherein the photoinitiator and the (meth)acrylic polymer are joined to one another via a bond, and the (meth)acrylic polymer comprises, in polymerized form, the photoinitiator monomer.
11. The composition of claim 1 , wherein the (meth)acrylic polymer has an acid number in a range from 0.1 to 40 mg KOH/g, measured in accordance with DIN EN ISO 2114.
12. The composition of claim 1 , further comprising:
an amine accelerant.
13. The composition of claim 1 , in the form of an aqueous dispersion.
14. A process for producing a coating, the process comprising:
applying the coating composition of claim 1 to a substrate, to obtain a coated substrate; and
curing the coated substrate.
15. The process of claim 14 , wherein the coating composition applied to the substrate is cured by exposure to light having a wavelength in a range from 200 to 800 nm,
wherein a luminous intensity of the light is in a range from 0.1 to 100 mW/cm 2 .
16. A coated article, obtained by the process of claim 14 .
17. The composition of claim 1 , comprising a maximum of 0.5% by weight of (meth)acrylic monomers comprising two or more (meth)acryl ate groups, based on a total weight of monomers.
18. The composition of claim 1 , comprising a maximum of 0.1% by weight of (meth)acrylic monomers comprising two or more (meth)acrylate groups, based on a total weight of monomers.
19. The composition of claim 1 , wherein the photoinitiator is a photoinitiator monomer of formula (I) or a photoinitiator polymer comprising, in polymerized form, the photoinitiator monomer of formula (I):
wherein:
R 1 is hydrogen or methyl;
R 2 is hydrogen, halogen, hydroxyl, or a radical comprising 1 to 20 carbon atoms;
R 3 is a radical comprising 1 to 20 carbon atoms;
X is oxygen or a group of formula NR′, wherein R′ is hydrogen or a radical comprising 1 to 6 carbon atoms;
m is an integer in the range from 0 to 4; and
Z is a bond or a linking group of formula (II):
wherein:
R 4 is a bond, oxygen, sulphur, or a group of the formula NR′, wherein R′ is hydrogen or a radical comprising 1 to 6 carbon atoms, O—CO—O, HN—CO—O, HN—CO—NH, or a linking group comprising 1 to 20 carbon atoms;
R 5 , R 6 , and R 7 are each independently a hydrogen or methyl;
n is an integer from 0 to 200; and
o and p are each independently an integer from 0 to 2.
20. The composition of claim 19 , wherein, in formula (I), R 3 is an aromatic or heteroaromatic radical.
21. The composition of claim 20 , wherein the photoinitiator monomer of formula (I) has formula (III):
wherein:
R 8 is hydrogen, halogen, hydroxyl, or a radical comprising 1 to 20 carbon atoms; and
r is an integer from 0 to 5.
22. The composition of claim 21 , wherein, in formula (III), Z is a linking group of formula (II), and wherein, in formula (II), n is an integer from 1 to 20.
23. The composition of claim 21 , wherein, in formula (III), Z is a bond.