Accelerated organoborane amine complex initiated polymerizable compositions
View Patent ↗The invention is a two part polymerizable composition comprising in one part an organoboron compound capable of forming free radical generating species amine complex and in the second part one or more compounds capable of free radical polymerization and a cure accelerator comprising a) at least one compound containing a quinone structure or b) at least one compound containing at least one aromatic ring and one or more, preferably two substituents on the aromatic ring selected from hydroxyl, ether and both, where there are two substituents they are located either ortho or para with respect to one another and a peroxide containing compound. The second part may further contain an agent capable of causing the organoboron compound to form free radical generating species upon contacting the two parts. The first part may further comprises one or more compounds capable of free radical polymerization. This facilitates formulating compositions that have commercially desirable volumetric ratios of the two parts. Adhesive compositions of the present formulation provide excellent adhesion to low surface energy substrates, such as plastics.
1. A two part polymerizable composition comprising in one part, an organoboron compound comprising an trialkylboron amine complex capable of forming free radical generating species and in the second part, one or more compounds capable of free radical polymerization and a cure accelerator comprising about 0.1 to about 4.0 percent by weight based on the weight of the two part polymerizable composition of at least one compound containing at least one alkyl ether of hydroquinone and the cure accelerator further comprising about 0.1 to about 4.0 percent by weight of a peroxide-containing compound selected from the group consisting of dialkyl peroxides, diaryl peroxides, diacyl peroxides, benzoyl peroxide and t-butylperbenzoate that reacts with the at least one compound containing at least one alkyl ether of hydroquinone to form free radicals; wherein the molar ratio of peroxide-containing compound to the at least one compound containing at least one alkyl ether of hydroquinone is one or less; and a decomplexing agent capable of decomplexing the organoboron amine complex upon containing of the two parts,
the cure accelerator is located only in the second part;
the parts of the polymerizable composition prior to contacting of the two parts exhibit a viscosity increase of less than 150 percent over 30 days when stored at 40° C. or less and the polymerizable composition exhibits a lap shear strength according to ASTM 03165-91 of 50 psi or greater 2 hours after contacting and application to a polypropylene substrate;
wherein:
the organoboron compound further comprises a compound having a primary amine and one or more hydrogen accepting groups, wherein the one or more hydrogen bond accepting groups is selected from ether or polyether, and there are at least one two carbon atoms between primary amine and the hydrogen bond accepting groups, wherein the compound having a primary amine and one or more hydrogen accepting groups is selected from the group consisting of methoxypropylamine, methoxybutylamine, methoxyethylamine, ethoxypropylamine, propoxypropylamine, and amine terminated polyalkylene ethers, and the compounds capable of free radical polymerization comprise acrylate or methacrylate monomers, polymers or a mixture thereof.
2. The composition according to claim 1 wherein the peroxide containing compound consists of t-butyl peroxide, benzoyl peroxide and t-butylperbenzoate.
3. The composition according to claim 1 wherein the peroxide containing compound consists of t-butylperbenzoate.
4. The composition according to claim 1 wherein the alkyl groups on the trialkyl boron compound are C 1-10 alkyl groups.
5. The composition according to claim 1 wherein the first part further comprises one or more compounds capable of free radical polymerization selected from the group consisting of acrylate or methacrylate monomers, polymers and mixtures thereof.
6. The composition according to claim 1 wherein said at least one alkyl ether of hydroquinone corresponds to the formula
wherein:
R 8 is separately in each occurrence R 9 ;
R 9 is separately in each occurrence C 1-10 alkyl or C 6-14 aryl;
R 10 is separately in each occurrence hydrogen or C 1-20 alkyl;
d is separately in each occurrence an integer of from 0 to 1 and e is 1.
7. The composition according to claim 1 , wherein said at least one alkyl ether of hydroquinone is a methyl ether of hydroquinone.