Polyester-polyurethane hybrid resin molding compositions comprising polyurethane with units derived from aliphatic isocyanates
View Patent ↗A hybrid resin composition is described, the composition comprising: A. An A part composition comprising an aliphatic polyfunctional isocyanate compound and a free radical polymerization initiator; and B. A B part composition comprising an ethylenically unsaturated, substantially water-free polyester polyol and a polyurethane catalyst. The A part composition can contain a non-interfering solvent, e.g., styrene, and the B part composition typically has an acid value of 5 or less (based on solids). For outdoor use, the B part composition is preferably free of tertiary hydrogens, ether glycols and terephthalic acid residues.
1. A curable hybrid resin composition for preparing a gel coat, the curable hybrid resin composition comprising:
A. An A part composition comprising an aliphatic polyfunctional isocyanate compound and a free radical polymerization initiator, and optionally a non-interfering solvent; and
B. A substantially water-free B part composition comprising an ethylenically unsaturated, substantially water-free, polyester polyol and a polyurethane catalyst, and having a hydroxyl number of about 120-170; and
either the A part or B part composition comprising a thixotropic agent and one or more additives;
wherein when the curable hybrid resin composition is cured at room temperature to form a cured composition, the polymer component of the cured composition consists of the hybrid resin and the hybrid resin consists of polyester and polyurethane units.
2. The composition of claim 1 wherein the isocyanate compound is at least one of 2,2,4-trimethyl-hexamethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and biuret and cyclic trimer derivatives thereof.
3. The composition of claim 2 wherein the isocyanate compound is hexamethylene diisocyanate.
4. The composition of claim 3 wherein the hexamethylene is a cyclic trimer derivative.
5. The composition of claim 2 wherein the polyester polyol comprises at least one dicarboxylic alkene moiety.
6. The composition of claim 5 wherein the polyester polyol comprises an oligomer of an α,β-ethylenically unsaturated dicarboxylic acid compound obtained by the condensation reaction of one or more saturated di- or polycarboxylic acid or anhydride and an unsaturated di- or polycarboxylic acid or anhydride with a glycol or a polyhydric alcohol.
7. The composition of claim 6 wherein the free radical polymerization initiator is at least one of a peroxide, persulfide, perborate, percarbonate, and azo compound.
8. The composition of claim 7 wherein the polyurethane catalyst is at least one of a tertiary amine, tertiary phosphine, strong base, acidic metal salt, and an organometallic compound.
9. A composite molded article, wherein it is made by curing the composition as defined according to claim 1 .
10. A gel coat, wherein it is made by curing a curable hybrid resin composition at room temperature, the curable hybrid resin composition comprising:
A. An A part composition comprising an aliphatic polyfunctional isocyanate compound and a free radical polymerization initiator, and optionally a non-interfering solvent; and
B. A substantially water-free B part composition comprising an ethylenically unsaturated, substantially water-free, polyester polyol and a polyurethane catalyst, and having a hydroxyl number of about 120-170; and
either the A part or B part composition comprising a thixotropic agent and at least one of a filler and a pigment; and
wherein the polymer component of the cured gel coat consists of the hybrid resin and the hybrid resin consists of polyester and polyurethane units.
11. A gel coat according to claim 10 , coated on a composite molded substrate made from a hybrid resin according to claim 1 or from an unsaturated polyester resin, vinyl ester or thermosetting resin.
12. An article comprising the gel coat of claim 10 .
13. An article comprising the gel coat of claim 11 .
14. The composition of claim 1 wherein the B part composition comprises less than about 2000 ppm of water, based on the total weight of the B part composition.
15. The composition of claim 1 , wherein the B part composition comprises less than about 1000 ppm of water, based on the total weight of the B part composition.
16. The gel coat of claim 10 , wherein the B part composition has an acid value of about 10 or less and a hydroxyl number of about 120-170.
17. The gel coat of claim 10 , wherein the A part composition comprises a non-interfering solvent selected from the group of ethylenically unsaturated monomers consisting of styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, methyl acrylate, methyl methacrylate, t-butylstyrene, divinyl benzene, diallyl phthalate, triallyl cyanurate, and mixtures thereof.
18. The gel coat of claim 10 , wherein the hybrid resin composition comprises about 10-50% by weight of the A part composition, and about 50-90% by weight of the B part composition.
19. The gel coat of claim 10 , wherein the B part composition further comprises said thixotropic agent at a weight content from about 0.2 to 5% by weight of the B part composition, said thixotropic agent selected from the group consisting of fumed silica, fatty acid amides and clays.