2K Curable Compositions for Composite and Tool Release
The present disclosure relates generally to two part adhesive compositions comprising a thiol part including a component having thiol functionality and a (meth)acrylate functional part including a polyolefin polymer having (meth)acrylate functionality. 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 thiol part comprising a compound comprising a thiol functional group;
a (meth)acrylate part comprising a (meth)acrylate functional polymer including one or more polyolefin segments and two or more (meth)acrylate functional groups, and reactive diluent;
optionally a filler, a catalyst, 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, preferably less than 600 psi and more preferably less than 300 psi, when tested using a lap shear test and the lap shear test sample exhibits at least some adhesive failure.
2 . The curable, two component, mold blocking material of claim 1 , wherein the thiol part compound is a mercaptan terminated oligomer or polymer.
3 . The curable, two component, mold blocking material of claim 1 , wherein the thiol part compound has an average functionality of 2 or more.
4 . The curable, two component, mold blocking material of claim 1 , wherein the polyolefin segments in the (meth)acrylate functional polymer are selected from polybutylene, polyisobutylene, polybutadiene, polyisoprene and combinations thereof.
5 . The curable, two component, mold blocking material of claim 1 , wherein the (meth)acrylate functional polymer comprises two polyolefin segments connected by an aryl group.
6 . The curable, two component, mold blocking material of claim 1 , wherein each (meth)acrylate functional group is terminally positioned and connected to a polyolefin segment by a-(phenyl-O-alkyl)-linking group
7 . The curable, two component, mold blocking material of claim 1 , wherein the filler, the catalyst, the additive or the combination thereof is in the thiol part, the (meth)acrylate part or both.
8 . The curable, two component, mold blocking material of claim 1 , wherein the reactive diluent consists of a polyfunctional methacrylate monomer.
9 . The curable, two component, mold blocking material of claim 1 , wherein the cured reaction products have an at least 70%, preferably 80% and more preferably greater than 90% adhesive failure mode.
10 . The mold blocking material of claim 1 , wherein the mixed mold blocking material has a gel time of 1 to 30 minutes; and/or a surface tack free time of 1 to 60 minutes; and/or a room temperature cure time of 1 hour to 168 hours.
11 . The curable, two component, mold blocking material of claim 1 , wherein the cured reaction products have a room temperature cure hardness of 20 to 80 Shore A; and/or a thermal resistance of 20 to 90 Shore A.
12 . (canceled)