Dual cure composite resins containing uretdione and unsaturated sites
The present invention provides a dual-cure composition containing multifunctional polyols, uretidiones, peroxide curable monomers containing unsaturation and crosslinking agents. The dual-cure composition may be used to form a high modulus material useful as the matrix in a prepreg material and in composites. The present invention also relates to methods for the production of the dual-cure composition, prepreg materials comprising the dual-cure composition and a fibrous support, and composites made from the prepreg material.
1. A process for the production of a dual-cure composite comprising:
homogenizing a pre-polymer composition comprising:
(A) a multifunctional polyol;
(B) a curing agent containing uretdione groups;
(C) a low viscosity unsaturated reactive diluent;
(ii) heating the pre-polymer composition to a temperature above the Tg of said component (B);
(iii) cooling the heated pre-polymer composition to a temperature of less than 110° C.;
(iv) mixing the cooled pre-polymer composition with a dual-cure catalyst composition to form a dual-cure composition, the catalyst composition comprising:
(D) at least one reactively activatable catalyst; and
(E) a thermal crosslinking initiator;
(v) curing the dual-cure composition at a temperature of from 80° C. to 130° C. for a period of time sufficient to form a cured composite.
2. The process for the production of a dual-cure composite of claim 1 , further comprising the additional step of:
(vi) adding a component (F), which is a fibrous support material to said pre-polymer composition during and/or after step (i) but before step (v).
3. The process for the production of a dual-cure composite of claim 1 , wherein the final density of the cured composite is less than 1.15 g/ml.
4. The process for the production of a dual-cure composite of claim 1 , wherein the dual-cure composition has a Tg of from −20° C. to +20° C. and the cured composite has a Tg of from 70° C. to 130° C.
5. The dual-cure composite made according to the process of claim 1 .
6. A prepreg material comprising:
(i) at least one fibrous material support, and
(ii) a dual-cure composition comprising:
(A) a multifunctional polyol;
(B) a curing agent containing uretdione groups;
(C) a low viscosity unsaturated reactive diluent;
(D) at least one reactively activatable catalyst; and
(E) a thermal crosslinking initiator.
7. The prepreg material of claim 6 , wherein said fibrous material support comprises at least one of carbon, aramid, glass, ceramic, quartz, boron, polyester, polyethylene, polyoxazoline or natural fibers.
8. The prepreg material of claim 6 , wherein the heat of polymerization of the dual-cure composition is less than 130 J/g.
9. The prepreg material of claim 6 , wherein the prepreg is converted to a composite component by exposure to a temperature of from 80° C. to 130° C. for a period of time sufficient to form a cured composite.