Polyurethane (meth)acrylate oligomers and curable compositions comprising said oligomers
View Patent ↗A polyurethane (meth)acrylate oligomer, having a tri-block symmetric structure BAB, comprises a polyether central block A linked by two urethane bonds to respectively two terminal hydrophobic blocs B based on hydrophobic polyester oligomers having a terminal (meth)acryloyloxy alkylene group. A curable composition (1k) comprises the oligomer and may be used for soft touch coatings in electronics, consumer goods and vehicle manufacture, as the resulting cured soft touch coating.
1. A curable coating composition suitable for use in soft touch coatings, wherein the composition comprises at least one polyurethane (meth)acrylate oligomer, wherein the oligomer has a tri-block symmetric structure B—A—B, comprising a polyether central block A linked by urethane bonds of two diisocyanate molecules, to respectively two terminal hydrophobic blocks B, wherein polyether central block A is based on polyoxyethylene or oligomers of polyethoxy-propoxy copolymers and hydrophobic blocks B are based on hydrophobic polyester oligomers generated from a polycaprolactone comprising 6 to 30 ester repeating units, having a terminal (meth)acryloyloxy alkylene group.
2. The composition according to claim 1 , wherein the oligomer has the following general formula (I):
B—OCONH—R—NHCOO—A—OCONH—R—NHCOO—B (I)
with
A: the residue of a polyether diol OCONH—RNHCOO: urethane link or bond of a diisocyanate R—(NCO) 2 with R being the residue of said diisocyanate,
B: the residue of a hydrophobic polyester oligomer, bearing in terminal position a (meth)acryloyloxy alkylene group linked to said polyester oligomer, by an ester bond (—CO 2 —).
3. The composition according to claim 1 , wherein said alkylene in said (meth)acryloyloxy alkylene terminal group is a C2 to C8 alkylene.
4. The composition according to claim 1 , wherein said block B corresponds to the following formula (II) —((CH 2 ) 5 -CO 2 ) n —R 1 —CO 2 —C(R 2 )═CH 2: with R 1 : being C 2 to C 8 alkylene and R 2 : being H or methyl, and n is from 6 to 30.
5. The composition according to claim 1 , wherein the chain length of the polyether block A corresponds to an Mn a number average molecular weight calculated from OH value of from 150 to 3000, or alternatively it corresponds to an average number of repeating alkoxy units from 3 to 75.
6. Curable composition according to claim 1 , wherein it is a radiation-curable composition, said radiation being selected from UV, electron beam, laser, LED.
7. Curable composition according to claim 1 , further comprising in addition to said oligomer, a curable (meth)acrylic monomer with a (meth)acrylate functionality of at least 1.
8. A curable composition according to claim 1 , further comprising a photoinitiator.
9. A curable composition according to claim 1 , further comprising at least one additive selected from: dispersing agent, colorant, matting agent, de-foaming agent and leveling agent.
10. A curable composition according to claim 1 , wherein the composition is a varnish, ink or a paint composition.
11. Curable composition according to claim 1 , wherein the composition is suitable for use in soft touch coatings in electronics, consumer goods and vehicle internal parts.
12. Curable composition according to claim 1 , wherein it is a 1 K curable-composition.
13. A method of preparing a soft touch coating comprising curing the curable composition of claim 1 .
14. The method of claim 13 , wherein said soft touch coatings are for electronics, consumer goods and vehicle manufacture.
15. Cured coating, wherein it results from the cure of the curable composition claim 1 .
16. Cured coating according to claim 15 , wherein it is a soft touch coating for electronics.
17. Cured coating according to claim 16 , wherein the coating is applied to a substrate selected from metal, plastic, polyolefin, polyamide, cellulosic polymer, polystyrene, polyacrylic, rubber, polycarbonate, polyurethane, polymeric fiber-reinforced composite, wood, wood composite, particle board, cement, stone, glass, paper, cardboard, textile, synthetic or natural leather.
18. Cured coating according to claim 16 , wherein the coating is a soft touch coating for electronics which are consumer electronics selected from:
computers, notebooks, smartphones, tablets, televisions, gaming equipment, computer equipment, computer accessories, MP3 players, consumer goods including handles of gardening tools, kitchen tools and household products, and vehicle manufacture for the internal decoration and steering wheel.