Bonding surfaces with permanent-bond adhesive

Claim 1

A method of providing both an initial bond and a permanent bond with one adhesive between two surfaces, at least one surface being a resin selected from the group consisting of an elastoplastic organopolysiloxane resin and a polytetrafluoroethylene resin, consisting essentially of (A) applying to the surfaces to be bonded a sufficient amount of a single permanent-bond adhesive to yield a coating of at least 0.1 mm thickness per surface, the adhesive consisting essentially of the product obtained by mixing (i) 9 to 70 percent by weight of a hydroxyl radical containing solid benzene soluble resin copolymer consisting essentially of R 3 SiO 1/2 units and SiO 4/2 units where R is a monovalent hydrocarbon radical containing no more than 6 carbon stoms, there being from 0.6 to 0.9 inclusive R 3 SiO 1/2 units for every SiO 4/2 units, at least 95 percent of all R radicals in (i) being methyl, (ii) 30 to 91 percent by weight of a polydiorganosiloxane of the formula HO(R.sub.2 SiO).sub.a H where R is as defined above, a has an average value such that (ii) has a viscosity of greater than 10,000 Pa.s at 25° C., (iii) 0.75 to 8 parts by weight based upon 100 parts by weight of (i) plus (ii) of an organohydrogenpolysiloxane compatible with the mixture of (i) and (ii) and having an average unit formula R.sub.b H.sub.c SiO(4-b-c)/2 where R is as defined above, b has a value of from 1.00 to less than 2.00, c has a value of from 0.3 to 1.00, the sum of b plus c being from 1.30 to less than 3.00, there being an average of greater than two silicon bonded hydrogen atoms per molecule of (iii), no silicon atom bearing more than one silicon bonded hydrogen atom, the mole ratio of SiH units in (iii) to SiOH units in (i) and (ii) being from 0.2/1 to 1/1, and the weight of hydrogen atoms present on silicon being less than 0.05 g per 100 g of (i) plus (ii), (iv) 0.5 to 2 parts by weight based upon 100 parts by weight of (i) plus (ii) of a soluble tin catalyst, and (v) sufficient non-reactive solvent for the mixture of (i), (ii), (iii), and (iv), to yield a flowable adhesive having a combination of viscosity and solids content such that a single application of adhesive can yield an adhesive thickness at least 0.1 mm, (B) allowing the solvent to evaporate until tacky adhesive surfaces are formed, then (C) placing the adhesive surfaces together while the adhesive is tacky, obtaining an initial load-bearing bond then (D) allowing the adhesive to further cure to give a permanent bond.

Claim 2

A method of providing both an initial bond and a permanent bond with one adhesive between two surfaces, at least one surface being a resin selected from the group consisting of an elastoplastic organopolysiloxane resin and a polytetrafluoroethylene resin, consisting essentially of (A) applying to the surfaces to be bonded a sufficient amount of a single permanent-bond adhesive to yield a coating of at least 0.1 mm thickness per surface, the adhesive consisting essentially of the product obtained by mixing (i) 9 to 70 percent by weight of a hydroxyl radical containing solid benzene soluble resin copolymer consisting essentially of R 3 SiO 1/2 units and SiO 4/2 units where R is a monovalent hydrocarbon radical containing no more than 6 carbon stoms, there being from 0.6 to 0.9 inclusive R 3 SiO 1/2 units for every SiO 4/2 units, at least 95 percent of all R radicals in (i) being methyl, (ii) 30 to 91 percent by weight of a polydiorganosiloxane of the formula HO(R.sub.2 SiO).sub.a H where R is as defined above, a has an average value such that (ii) has a viscosity of greater than 10,000 Pa.s at 25° C., (iii) 0.75 to 8 parts by weight based upon 100 parts by weight of (i) plus (ii) of an organohydrogenpolysiloxane compatible with the mixture of (i) and (ii) and having an average unit formula R.sub.b H.sub.c SiO(4-b-c)/2 where R is as defined above, b has a value of from 1.00 to less than 2.00, c has a value of from 0.3 to 1.00, the sum of b plus c being from 1.30 to less than 3.00, there being an average of greater than two silicon bonded hydrogen atoms per molecule of (iii), no silicon atom bearing more than one silicon bonded hydrogen atom, the mole ratio of SiH units in (iii) to SiOH units in (i) and (ii) being from 0.2/1 to 1/1, and the weight of hydrogen atoms present on silicon being less than 0.05 g per 100 g of (i) plus (ii), (iv) 0.5 to 2 parts by weight based upon 100 parts by weight of (i) plus (ii) of a soluble tin catalyst, and (v) sufficient non-reactive solvent for the mixture of (i), (ii), (iii), and (iv), to yield a flowable adhesive having a combination of viscosity and solids content such that a single application of adhesive can yield an adhesive thickness at least 0.1 mm, (B) allowing the solvent to evaporate until tacky adhesive surfaces are formed, then (C) placing the adhesive surfaces together while the adhesive is tacky, obtaining an initial load-bearing bond then (D) allowing the adhesive to further cure to give a permanent bond.

Claim 29

A method of providing both an initial bond and a permanent bond with one adhesive between two surfaces at least one surface being a resin selected from the group consisting of an elastoplastic organopolysiloxane resin and a polytetrafluoroethylene resin, consisting of (A) applying to the surfaces to be bonded a sufficient amount of a single permanent-bond adhesive to yield a coating of at least 0.1 mm thickness per surface, the adhesive consisting essentially of the product obtained by mixing (i) 9 to 70 percent by weight of a hydroxyl radical containing solid benzene soluble resin copolymer consisting essentially of R 3 SiO 1/2 units and SiO 4/2 units where R is a monovalent hydrocarbon radical containing no more than 6 carbon atoms, there being from 0.6 to 0.9 inclusive R 3 SiO 1/2 units for every SiO 4/2 units, at least 95 percent of all R radicals in (i) being methyl, (ii) 30 to 91 percent by weight of a polydiorganosiloxane of the formula HO(R.sub.2 SiO).sub.a H where R is as defined above, a has an average value such that (ii) has a viscosity of greater than 10,000 Pa.s at 25° C., (iii) 0.75 to 8 parts by weight based upon 100 parts by weight of (i) plus (ii) of an organohydrogenpolysiloxane compatible with the mixture of (i) and (ii) and having an average unit formula R.sub.b H.sub.c SiO(4-b-c)/2 where R is as defined above, b has a value of from 1.00 to less than 2.00, c has a value of from 0.3 to 1.00, the sum of b plus c being from 1.30 to less than 3.00, there being an average of greater than two silicon bonded hydrogen atoms per molecule of (iii), no silicon atom bearing more than one silicon bonded hydrogen atom, the mole ratio of SiH units in (iii) to SiOH units in (i) and (ii) being from 0.2/1 to 1/1, and the weight of hydrogen atoms present on silicon being less than 0.05 g per 100 g of (i) plus (ii), (iv) 0.5 to 2 parts by weight based upon 100 parts by weight of (i) plus (ii) of a soluble tin catalyst, and (v) sufficient non-reactive solvent for the mixture of (i), (ii), (iii), and (iv), to yield a flowable adhesive having a combination of viscosity and solids content such that a single application of adhesive can yield an adhesive thickness at least 0.1 mm, (B) allowing the solvent to evaporate until tacky adhesive surfaces are formed, then (C) placing the adhesive surfaces together while the adhesive is tacky, obtaining an initial load-bearing bond then (D) allowing the adhesive to further cure to give a permanent bond.

Claim 30

A method of providing both an initial bond and a permanent bond with one adhesive between two surfaces at least one surface being a resin selected from the group consisting of an elastoplastic organopolysiloxane resin and a polytetrafluoroethylene resin, consisting of (A) applying to the surfaces to be bonded a sufficient amount of a single permanent-bond adhesive to yield a coating of at least 0.1 mm thickness per surface, the adhesive consisting essentially of the product obtained by mixing (i) 9 to 70 percent by weight of a hydroxyl radical containing solid benzene soluble resin copolymer consisting essentially of R 3 SiO 1/2 units and SiO 4/2 units where R is a monovalent hydrocarbon radical containing no more than 6 carbon atoms, there being from 0.6 to 0.9 inclusive R 3 SiO 1/2 units for every SiO 4/2 units, at least 95 percent of all R radicals in (i) being methyl, (ii) 30 to 91 percent by weight of a polydiorganosiloxane of the formula HO(R.sub.2 SiO).sub.a H where R is as defined above, a has an average value such that (ii) has a viscosity of greater than 10,000 Pa.s at 25° C., (iii) 0.75 to 8 parts by weight based upon 100 parts by weight of (i) plus (ii) of an organohydrogenpolysiloxane compatible with the mixture of (i) and (ii) and having an average unit formula R.sub.b H.sub.c SiO(4-b-c)/2 where R is as defined above, b has a value of from 1.00 to less than 2.00, c has a value of from 0.3 to 1.00, the sum of b plus c being from 1.30 to less than 3.00, there being an average of greater than two silicon bonded hydrogen atoms per molecule of (iii), no silicon atom bearing more than one silicon bonded hydrogen atom, the mole ratio of SiH units in (iii) to SiOH units in (i) and (ii) being from 0.2/1 to 1/1, and the weight of hydrogen atoms present on silicon being less than 0.05 g per 100 g of (i) plus (ii), (iv) 0.5 to 2 parts by weight based upon 100 parts by weight of (i) plus (ii) of a soluble tin catalyst, and (v) sufficient non-reactive solvent for the mixture of (i), (ii), (iii), and (iv), to yield a flowable adhesive having a combination of viscosity and solids content such that a single application of adhesive can yield an adhesive thickness at least 0.1 mm, (B) allowing the solvent to evaporate until tacky adhesive surfaces are formed, then (C) placing the adhesive surfaces together while the adhesive is tacky, obtaining an initial load-bearing bond then (D) allowing the adhesive to further cure to give a permanent bond.