Adhesive bonding method

Claim 2

In a method for the adhesive bonding of two surfaces, the steps comprising: (1) forming a stable nonanaerobic adhesive composition comprised of: (a) a monomeric acrylic ester capable of free-radical polymerization to produce, upon polymerization thereof, an adhesive solid, (b) a monomer-soluble elastomeric filler material for toughening and/or strengthening the cured adhesive composition, and (c) a latent catalyst system consisting, in amounts based upon the weight of said ester, essentially of about 1 to 10 parts per hundred of an aromatic perester free-radical precursor, about 0.5 to 10 parts per hundred of an organic acid capable of cyclic tautomerism, and up to about 500 parts per million of a soluble compound of a transition metal cure accelerator, said composition being free from any organic hydroperoxide catalyst; (2) applying said adhesive composition to at least one surface to be bonded; (3) effecting contact of said one surface with a second surface to be bonded thereto; (4) activating said perester catalyst to generate free radicals; and (5) maintaining such contact for a period of time and under such conditions as to effect curing of said adhesive composition.

Claim 3

The method of claim 1 wherein said conditions include the presence of oxygen between said surfaces.

Claim 4

The method of claim 1 wherein said surfaces are separated by a gap in excess of about 15 mils.

Claim 5

In a method for the adhesive bonding of two surfaces, the steps comprising: (1) forming a stable nonanaerobic adhesive composition comprised of: (a) a monomeric acrylic ester capable of free-radical polymerization to produce, upon polymerization thereof, an adhesive solid, (b) a monomer-soluble elastomeric filler material for toughening and/or strengthening the cured adhesive composition, and (c) a latent catalyst system consisting, in amounts based upon the weight of said ester, essentially of about 1 to 10 parts per hundred of an aromatic perester free-radical precursor, about 0.5 to 10 parts per hundred of an organic acid capable of cyclic tautomerism, and up to about 500 parts per million of a soluble compound of a transition metal cure accelerator, said composition being free from any organic hydroperoxide catalyst; (2) applying said adhesive composition to at least one surface to be bonded; (3) applying to at least one surface to be bonded an aminealdehyde adduct activator for said perester free radical precursor of said composition, said activator being capable of activating said perester catalyst so as to generate free radicals; (4) effecting contact of said two surfaces; and (5) maintaining such contact for a period of time and under such conditions as to effect curing of said adhesive composition.

Claim 6

In a method for the adhesive bonding of two surfaces, the steps comprising: (1) forming a stable nonanaerobic adhesive composition comprised of: (a) a monomeric acrylic ester capable of free-radical polymerization to produce, upon polymerization thereof, an adhesive solid, (b) a monomer-soluble elastomeric filler material for toughening and/or strengthening the cured adhesive composition, and (c) a latent catalyst system consisting, in amounts based upon the weight of said ester, essentially of about 1 to 10 parts per hundred of an aromatic perester free-radical precursor, about 0.5 to 10 parts per hundred of an organic acid capable of cyclic tautomerism, and up to about 500 parts per million of a soluble compound of a transition metal cure accelerator, said composition being free from any organic hydroperoxide catalyst; (2) applying said adhesive composition to at least one surface to be bonded; (3) applying to at least one surface to be bonded an aminealdehyde adduct activator for said perester free radical precursor of said composition, said activator being capable of activating said perester catalyst so as to generate free radicals; (4) effecting contact of said two surfaces; and (5) maintaining such contact for a period of time and under such conditions as to effect curing of said adhesive composition.

Claim 7

In a method for the adhesive bonding of two surfaces, the steps comprising: (1) forming a stable nonanaerobic adhesive composition including an adhesive comprising: a. about 40 to 90 parts per hundred of an acrylic ester monomer capable of free-radical polymerization, and b. about 60 to 10 parts per hundred of an elastomeric filler that is soluble in said monomer and is reactive therewith to produce intermolecular bonding upon polymerization thereof, and thereby producing strengthening and/or toughening in the cured adhesive, said filler being selected from the group consisting of vinyl polymers, acrylic elastomer, polyester elastomers, glycol polymers, urethane elastomers, urethane prepolymers, and natural and synthetic rubbers, and a catalyst system consisting, in amounts based upon the weight of said adhesive, essentially of: c. about 1 to 10 parts per hundred of an aromatic perester free-radical precursor, d. about 0.5 to 10 parts per hundred of an organic acid capable of cyclic tautomerism, and e. up to about 500 parts per million of a soluble compound of a transition metal cure accelerator, said composition being free from any organic hydroperoxide catalyst; (2) applying said adhesive composition to one surface to be bonded; (3) applying to another surface to be bonded to said one surface an amine-aldehyde adduct curing agent for said composition; (4) effecting contact of said surfaces to activate said perester catalyst with said curing agent so as to generate free radicals; and (5) maintaining such contact for a period of time and under such conditions as to effect curing of said adhesive composition.

Claim 8

In a method for the adhesive bonding of two surfaces, the steps comprising: (1) forming a stable nonanaerobic adhesive composition including an adhesive comprising: a. about 40 to 90 parts per hundred of an acrylic ester monomer capable of free-radical polymerization, and b. about 60 to 10 parts per hundred of an elastomeric filler that is soluble in said monomer and is reactive therewith to produce intermolecular bonding upon polymerization thereof, and thereby producing strengthening and/or toughening in the cured adhesive, said filler being selected from the group consisting of vinyl polymers, acrylic elastomer, polyester elastomers, glycol polymers, urethane elastomers, urethane prepolymers, and natural and synthetic rubbers, and a catalyst system consisting, in amounts based upon the weight of said adhesive, essentially of: c. about 1 to 10 parts per hundred of an aromatic perester free-radical precursor, d. about 0.5 to 10 parts per hundred of an organic acid capable of cyclic tautomerism, and e. up to about 500 parts per million of a soluble compound of a transition metal cure accelerator, said composition being free from any organic hydroperoxide catalyst; (2) applying said adhesive composition to one surface to be bonded; (3) applying to another surface to be bonded to said one surface an amine-aldehyde adduct curing agent for said composition; (4) effecting contact of said surfaces to activate said perester catalyst with said curing agent so as to generate free radicals; and (5) maintaining such contact for a period of time and under such conditions as to effect curing of said adhesive composition.

Claim 9

The method of claim 5 wherein said adhesive in said composition comprises about 50 to 80 parts per hundred of said acrylic ester monomer and about 50 to 20 parts per hundred of said elastomeric filler, and wherein the amount of said organic acid is at least about 1.0 part per hundred of said adhesive.

Claim 10

The method of claim 6 wherein said filler is a monomeric polyacrylate ester prepolymer having terminal acrylate radicals linked by at least two divalent polyurethane or polyureide groups.

Claim 11

The method of claim 4 or 5 wherein said conditions include the presence of oxygen between said surfaces.

Claim 12

The method of claim 4 or 5 wherein said surfaces are separated by a gap in excess of about 15 mils.

Claim 13

The method of claim 1, 4 or 5 wherein said organic acid in said composition is selected from the group consisting of maleic, malic, salicylic, itaconic and phthalic acids, and mixtures thereof.

Claim 14

The method of claim 1, 4 or 5 additionally including in said composition at least 50 parts per million of a transition metal compound selected from the class consisting of iron, copper, cobalt, manganese, tin, titanium, chromium and antimony, said perester catalyst being selected from the group consisting of t-butyl perbenzoate, di-t-butyl diperphthalate and 2,5-dimethyl-2,5-bis(benzoylperoxy) hexane.

Claim 15

The method of claim 1, 4 or 5 wherein said acrylic ester monomer in said composition comprises hydroxyethyl methacrylate.