Polyester hybrid resins
This invention relates to a polyester urethane hybrid resin casting resin composition which comprises a mixture ABCD of an unsaturated polyester ABC which has moieties derived from at least one alcohol A, moieties derived from a mixture B of carboxylic acids, wherein at least 10% of the mass of at least one of the said carboxylic acids B or of the said alcohols A have at least one olefinic unsaturation in their molecules, and moieties derived from a monoepoxide C having at least four carbon atoms, which polyester ABC is dissolved in a compound D, and which has at least one olefinic unsaturation and which is radically copolymerizable with the unsaturated polyester oligomer ABC and a second liquid component EF comprising a polyfunctional isocyanate E and a radical initiator F, a process for its production, and a method of use thereof to form large moulded parts.
1. A two-pack polyester urethane hybrid resin casting resin composition comprising:
a first constituent comprising a mixture ABCD of an unsaturated polyester ABC which has moieties derived from:
(i) at least one alcohol A,
(ii) a mixture of carboxylic acids B, wherein the alcohols A and carboxylic acids B form a resulting polyester AB having an acid number of at least 15 mg/g, and wherein at least 10% of the mass of at least one of the carboxylic acids B or of the alcohols A have at least one olefinic unsaturation in their molecules; and
(iii) a monoepoxide C having at least four carbon atoms,
which polyester ABC is dissolved in a compound D having at least one olefinic unsaturation and being radically copolymerisable with the unsaturated polyester ABC; and
a second constituent comprising a liquid component EF comprising a polyfunctional isocyanate E and a radical initiator F.
2. The two-pack polyester urethane hybrid resin casting resin composition of claim 1 wherein the first constituent additionally comprises a catalyst G for promoting radical formation, which catalyst G is selected from the group consisting of aromatic amines and metal salts.
3. The two-pack polyester urethane hybrid resin casting resin composition of claim 1 wherein the amount of alcohols A, carboxylic acids B, and monoepoxides C are chosen in a way to ensure that in the resulting polyester ABC, substantially all of the carboxyl groups are consumed by reaction with the monoepoxide C.
4. The two-pack polyester urethane hybrid resin casting resin composition of claim 1 wherein the monoepoxide is selected from the group consisting of the glycidyl and methyl glycidyl esters of branched aliphatic carboxylic acids having from 5 to 20 carbon atoms.
5. A process for the production of a two-pack polyester urethane hybrid casting resin composition according to claim 1 , comprising the steps of
reacting at least one alcohol A and a mixture of carboxylic acids B as defined in claim 1 to form an unsaturated polyester AB,
reacting the acidic unsaturated polyester AB formed in the first step with a monoepoxide C as defined in claim 1 to form a hydroxy functional polyester oligomer ABC,
dissolving the polyester ABC in a liquid compound D as defined in claim 1 to form a solution of a hydroxy functional polyester oligomer ABCD, and
adding a liquid isocyanate composition EF as defined in claim 1 to the mixture ABCD to form a casting resin composition.
6. A process for the production of a two-pack polyester urethane hybrid casting resin composition according to claim 1 , comprising the steps of
reacting at least one alcohol A and a mixture of carboxylic acids B as defined in claim 1 , to form an unsaturated polyester AB,
dissolving the acidic polyester AB in a liquid compound D as defined in claim 1 ,
reacting the acidic unsaturated polyester AB dissolved in D with a monoepoxide C as defined in claim 1 , to form a solution of a hydroxy functional polyester oligomer ABCD, and
adding a liquid isocyanate composition EF as defined in claims 1 to the mixture ABCD to form a casting resin composition.
7. The process of claim 5 further comprising adding a catalyst G to the solution of the hydroxy functional polyester oligomer ABCD to promote radical formation in the radical initiator F.
8. A method of use of the two-pack polyester urethane hybrid resin casting resin composition of claim 1 for the fabrication of moulded parts comprising
mixing the unsaturated polyester oligomer ABC as defined in claim 1 with a compound D as defined in claim 1 ,
adding thereto the liquid component EF as defined in claim 1 ,
casting the mixture thus obtained into a mould,
heating the mould to cure the contents of the mould to form a cured part,
opening the mould, and
removing the cured part.
9. The method of claim 8 further comprising adding a catalyst G to the mixture of ABCD to promote radical formation.
10. The process of claim 6 further comprising adding a catalyst G to the solution of the hydroxy functional polyester oligomer ABCD to promote radical formation in the radical initiator F.