Adhesives for bonding optical elements

Claim 2

An adhesive adapted especially for bonding optical elements consisting essentially of a polyfunctional acrylate and a polythiol, which are major components, a free radical generating photoinitiator, a free radical generating heat-activated curing initiator, and a stabilizer, (A) said polyfunctional acrylate being di-pentaerythritol hexacrylate, di-pentaerythritol pentacrylate or a mixture thereof, (B) said polythiol being pentaerythritol tetrakis (thioglycolate), trimethylol ethanetris (β-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropylether), a mixture consisting of any two of the above mentioned compounds or a mixture of all of said compounds the weight ratio of said polythiol to said polyfunctional acrylate being from 10:1 to 1:10.

Claim 3

An adhesive as set forth in claim 1 wherein: (a) said polyfunctional acrylate is the mixture of di-pentaerythritol hexacrylate and pentaerythritol pentacrylate; (b) said polythiol is pentaerythritol tetra-thiopropionate; (c) the weight ratio between said multi-sensitive acrylate and said polythiol is from 1:2 to 2:1, (d) said photocuring initiator is 0.1-10% by weight of ' -isopropyl-2-hydroxy-2-methylpropiophenol, 2-hydroxy-2-methylpropiophenol or benzyldimethylketal; and (e) said heat-curing initiator is 1-10% by weight of benzopinacol.

Claim 4

An adhesive as set forth in claim 1, wherein said polyfunctional acrylate is di-pentaerythritol hexacrylate, dipentaerythritol pentacrylate or a mixture thereof.

Claim 5

An adhesive as set forth in claim 1, wherein said polythiol is pentaerythritol tetrakis (thioglycolate), trimethylol ethanetris (β-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropylether), a mixture consisting of any two of the above mentioned compounds or a mixture of all of said compounds.

Claim 6

An adhesive as set forth in claim 1, wherein said photocuring initiator is 4'-isopropyl-2-hydroxy-2-methylpropiophenol, 2-hydroxy-2-methylpropiophenol or benzyldimethylketal.

Claim 7

An adhesive as set forth in claim 1, wherein said stabilizer is phosphorous acid, pyrogallol, 2,6-di-t-butyl-4-methylphenol, hydroquinone, or phenothiazine.

Claim 8

An adhesive as set forth in claim 1, wherein said photocuring initiator is 4'-isopropyl-2-hydroxy-2-methylpropiophenol, 2-hydroxy-2-methylpropiophenol or benzyldimethylketal, in an amount of 0.1-10% by weight.

Claim 9

An adhesive as set forth in claim 7, further characterized in that said heat curing initiator is 1-10% by weight of benzopinacol.

Claim 10

An adhesive as set forth in claim 8 wherein said stabilizer is phosphorous acid, pyrogallol, 2,6-di-t-butyl-4-methylphenol, hydroquinone, or phenothiazine.

Claim 11

An adhesive as set forth in claim 1, consisting essentially of d-pentaerythritol hexacrylate and pentaerythritol tetra-thiopropionate in a weight ratio of 1:1 to 0.8:1, 1-5% by weight of 4'-isopropyl-2-hydroxy-2-methylpropiophenol, 2-hydroxy-2-methylpropiophenol, or benzyldimethylketal; 1-5% by weight of benzopinacol; and an effective amount of phosphorous acid, pyrogallol, 2,6-di-t-butyl-4-methylphenol, hydroquinone, or phenothiazine, as a stabilizer.

Claim 12

An adhesive adapted especially for bonding optical elements consisting essentially of a polyfunctional acrylate and a polythiol, which are major components, a free radical generating photoinitiator, a free radical generating heat-activated curing initiator and a stabilizer, (A) said polyfunctional acrylate being di-pentaerythritol hexacrylate, di-pentaerythritol pentacrylate or a mixture thereof, (B) said polythiol being pentaerythritol tetrakis (thiolglycolate), trimethylol ethanetris (β-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropylether), a mixture consisting of any two of the above mentioned compounds or a mixture of all of said compounds the weight ratio of said polythiol to said polyfunctional acrylate being from 10:1 to 1:10, (C) said photoinitiator being 4'-isopropyl-2-hydroxy-2-methylpropiophenol, 2-hydroxy-2-methylpropiophenol or benzyldimethylketal, in an amount of 0.1-10% by weight, (D) said heat-activated curing initiator being 1-10% by weight of benzopinacol, and (E) said stabilizer being phosphorus acid, pyrogallol, 2,6-di-t-butyl-4-methylphenol, hydroquinone, or phenothiazine.

Claim 13

An adhesive adapted especially for bonding optical elements consisting essentially of a polyfunctional acrylate and a polythiol, which are major components, a free radical generating photoinitiator, a free radical generating heat-activated curing initiator and a stabilizer, (A) said polyfunctional acrylate being di-pentaerythritol hexacrylate, di-pentaerythritol pentacrylate or a mixture thereof, (B) said polythiol being pentaerythritol tetrakis (thiolglycolate), trimethylol ethanetris (β-mercaptopropionate), pentaerythritol tetrakis (3-mercaptopropylether), a mixture consisting of any two of the above mentioned compounds or a mixture of all of said compounds the weight ratio of said polythiol to said polyfunctional acrylate being from 10:1 to 1:10, (C) said photoinitiator being 4'-isopropyl-2-hydroxy-2-methylpropiophenol, 2-hydroxy-2-methylpropiophenol or benzyldimethylketal, in an amount of 0.1-10% by weight, (D) said heat-activated curing initiator being 1-10% by weight of benzopinacol, and (E) said stabilizer being phosphorus acid, pyrogallol, 2,6-di-t-butyl-4-methylphenol, hydroquinone, or phenothiazine.