Curable Compositions for Composite and Tool Release
The present disclosure relates generally to two part adhesive compositions comprising a resin part including a curable resin selected from multifunctional, hydroxyl di-terminated polymer having alkene segments and epoxide segments in the polymer chain; an epoxy di-terminated block copolymer having siloxane moieties and bisphenol A moieties in the backbone and combination thereof and a hardener part including a curative for the curable resin. When mixed the compositions cure to a form that provides hardness but relatively low bond strength to a substrate and which can be removed from metal and other surfaces easily and simply with little residue.
1 . A curable, two component, mold blocking material, including:
a resin part comprising,
a curable resin selected from multifunctional, hydroxyl di-terminated polymer having alkene segments and epoxide segments in the polymer chain; an epoxy di-terminated block copolymer having siloxane moieties and bisphenol A moieties in the backbone and combinations thereof;
optionally a reactive diluent, a non-reactive diluent, a release agent, a filler, an additive or a combination thereof;
a hardener part comprising,
at least one curative;
optionally a non-reactive diluent, a release agent, filler, an additive or a combination thereof;
wherein cured reaction products of the mixed mold blocking material have an adhesion strength of less than or equal to 1,000 psi when tested using a lap shear test and the lap shear test sample exhibits at least some adhesive failure.
2 . The mold blocking material of claim 1 wherein the resin part comprises at least one of the non-reactive diluent or the release agent.
3 . The mold blocking material of claim 1 comprising both up to 25 wt. % release agent and up to 30 wt. % non-reactive diluent in the resin part, in each case by weight of the resin part.
4 . The mold blocking material of claim 1 having no material comprising a backbone with more than 15 mole % of an aryl moiety.
5 . The mold blocking material of claim 1 having no material comprising a backbone with more than 15 mole % of bisphenol A moieties.
6 . The mold blocking material of claim 1 wherein non-reactive diluent is present in the resin part in an amount of up to 30 wt. % of non-reactive diluent by weight of the resin part.
7 . The mold blocking material of claim 1 further comprising release agent in the resin part or the hardener part.
8 . The mold blocking material of claim 1 wherein the mixed mold blocking material has an open time of 2 to 40 minutes; and/or a gel time of 1 to 30 minutes; and/or a room temperature cure time of 2 to 12 hours.
9 . Cured reaction products of the mixed mold blocking material of claim 1 having a tensile strength of less than 1,000 psi.
10 . Cured reaction products of the mixed mold blocking material of claim 1 having a room temperature cure hardness of greater than 10 Shore A.
11 . Cured reaction products of the mixed mold blocking material of claim 1 having a heat cure hardness of greater than 30 Shore A.
12 . (canceled)