US4539357A — Peroxide curing polysiloxane compositions having …

Claim 1

Independent Claim 190 words

A polysiloxane composition curable to a silicone elastomer comprising: (A) 60-95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having a viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of an organic peroxide free radical initiator curing agent.

Claim 2

Dependent Claim 190 words

A polysiloxane composition curable to a silicone elastomer comprising: (A) 60-95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having a viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of an organic peroxide free radical initiator curing agent.

Claim 3

Dependent Claim 75 words

The composition of claim 1 wherein the vinyl-terminated gum has the formula, ##STR7## where Vi is vinyl, R is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation, R 1 is a C 1-8 monovalent hydrocarbon radical, x and t vary such that the viscosity of the gum ranges from 1×10 6 to 20×10 7 centipoise at 25° C. and the vinyl concentration of the gum ranges from 0.005 to 0.1 mole percent vinyl.

Claim 4

Dependent Claim 15 words

The composition of claim 2 wherein the radical R 1 is free of aliphatic unsaturation.

Claim 5

Dependent Claim 20 words

The composition of claim 2 wherein the vinyl-terminated gum has a vinyl content varying from 0.01 to 0.08 mole percent.

Claim 6

Dependent Claim 75 words

The composition of claim 1 wherein the vinyl-containing gum has the formula, ##STR8## where R 2 and R 4 are C 1-8 monovalent hydrocarbon radicals, R 3 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation, w and z vary such that the viscosity of the gum ranges from 20×10 6 to 100×10 6 centipoise at 25° C. and wherein the vinyl concentration of the gum varies from 0.5 to 15.0 mole percent.

Claim 7

Dependent Claim 19 words

The composition of claim 5 wherein R 2 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation.

Claim 8

Dependent Claim 31 words

The composition of claim 1 wherein there is present from 10 to 200 parts by weight of a reinforcing filler selected from the group consisting of fumed silica and precipitated silica.

Claim 9

Dependent Claim 17 words

The composition of claim 7 wherein an extending filler is utilized in addition to the reinforcing filler.

Claim 10

Dependent Claim 23 words

The composition of claim 1 wherein the reinforcing filler is treated with treating agents selected from the class consisting of cyclopolysiloxanes and silazanes.

Claim 11

Dependent Claim 14 words

The composition of claim 1 wherein the curing agent is selected from organic peroxides.

Claim 12

Dependent Claim 20 words

The composition of claim 10 wherein the curing agent is selected from the group consisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide and 5-butylcumylperoxide.

Claim 13

Dependent Claim 20 words

The composition of claim 1 further comprising from 1 to 500 parts per million of a platinum catalyst cure accelerator.

Claim 14

Dependent Claim 64 words

The composition of claim 1 wherein the hydride-containing polysiloxane is a linear polysiloxane of the formula ##STR9## where R 5 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation, p and q vary such that the viscosity of the hydride polysiloxane ranges from 10 to 1000 centipoise at 25° C. and the hydride content varies from 0.05 to 2.0 percent by weight.

Claim 15

Dependent Claim 60 words

The composition of claim 1 where the hydride-containing polysiloxane is a hydride resin having ##STR10## and SiO 2 units where R 6 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation and the R 6 +H to Si ratio varies from 1.0 to 2.7 wherein the hydride content of the resin varies from 0.05 to 2.0 weight percent.

Claim 16

Dependent Claim 53 words

The composition of claim 1 wherein the hydride-containing polysiloxane is a hydride resin having ##STR11## and SiO 2 units and (R 6 ) 2 SiO units, where the R 6 +H to Si ratio varies from 1.2 to 2.7, and R 6 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation.

Claim 17

Dependent Claim 32 words

The composition of claim 1 wherein the curing agent is present at a concentration of at least 0.1 parts by weight for 100 parts by weight of the rest of the composition.

Claim 18

Dependent Claim 85 words

The composition of claim 1 further comprising from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R.sub.3.sup.8 --SiO.sub.0.5 units and SiO 2 units where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation with a ratio of R 3 8 --SiO 0 .5 units to SiO 2 units ranging from about 0.5 to 1 to 1 to 1, and where said copolymer contains about 2.5 to 10 mole percent vinyl groups.

Claim 19

Dependent Claim 130 words

The composition of claim 1 further comprising from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R 3 8 SiO 0 .5 units and SiO 2 units and R 2 8 SiO units where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of R 3 8 --SiO 0 .5 units to SiO 2 units is from about 0.5 to 1 to 1 to 1, and the R 2 8 --SiO units are present in an amount of from about 1 to 10 mole percent based on the total number of moles of siloxy units in the copolymer, and where the resinous copolymer contains from about 2.5 to 10.0 mole percent vinyl groups.

Claim 20

Dependent Claim 18 words

The composition of claim 1 further comprising from 1 to 25 parts by weight of a process aid.

Claim 21

Dependent Claim 75 words

The composition of claim 19 wherein the process aid is a dihydrocarbon substituted polysiloxane oil having a hydrocarbon substituent silicon atom ratio from 1.0 to 2.0 and where such hydrocarbon substituents comprise at least one member selected from the class consisting of methyl, vinyl, ethyl, allyl, cyclohexenyl and phenyl groups, said polysiloxane oil comprising polysiloxane molecules containing an average of from 1 to 2 lower alkoxy groups bonded to each of the terminal silicon atoms.

Claim 22

Dependent Claim 12 words

The composition of claim 10 wherein the curing agent is 2,5 dimethyl-2,5-di(t-butylperoxy)hexyne-3.

Claim 23

Dependent Claim 50 words

The composition of claim 19 wherein the process aid is a hydroxylated organosiloxane, a hydroxylated silane, or mixture thereof, said process aid containing on average from 1.9 to 2.1 hydrocarbon radicals per silicon atom and from 1 silicon-bonded OH per 70 silicon atoms to 2 silicon-bonded OH per silicon atom.

Claim 24

Dependent Claim 31 words

The composition of claim 16 wherein the curing agent is present in a concentration of from 0.1 to 2 parts by weight per 100 parts of the rest of the composition.

Claim 25

Dependent Claim 198 words

A process for making a polysiloxane composition that is curable to a silicone elastomer comprising mixing: (A) 60-95 parts by weight of a vinyl-terminaed linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of a hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having a viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of an organic peroxide free radical initiator curing agent.

Claim 26

Dependent Claim 198 words

A process for making a polysiloxane composition that is curable to a silicone elastomer comprising mixing: (A) 60-95 parts by weight of a vinyl-terminaed linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of a hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having a viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of an organic peroxide free radical initiator curing agent.

Claim 27

Dependent Claim 195 words

A cured silicone elastomeric article formed by curing a mixture comprising: (A) 60 to 95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of hydride containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight an having a viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of an organic peroxide free radical initiator curing agent.

Claim 28

Dependent Claim 195 words

A cured silicone elastomeric article formed by curing a mixture comprising: (A) 60 to 95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent vinyl and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl concentration in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of hydride containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight an having a viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of an organic peroxide free radical initiator curing agent.

Claim 29

Dependent Claim 75 words

The article of claim 25 wherein the vinyl-terminated gum has the formula, ##STR12## where Vi is vinyl, R is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation, R 1 is a C 1-8 monovalent hydrocarbon radical, x and t vary such that the viscosity of the gum ranges from 1×10 6 to 20×10 7 centipoise at 25° C. and the vinyl concentration of the gum ranges from 0.005 to 0.1 mole percent vinyl.

Claim 30

Dependent Claim 15 words

The article of claim 26 wherein the radical R 1 is free of aliphatic unsaturation.

Claim 31

Dependent Claim 20 words

The article of claim 26 wherein the vinyl-terminated gum has a vinyl content varying from 0.01 to 0.08 mole percent.

Claim 32

Dependent Claim 75 words

The article of claim 25 wherein the vinyl-containing gum has the formula, ##STR13## where R 2 and R 4 are C 1-8 monovalent hydrocarbon radicals, R 3 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation, w and z vary such that the viscosity of the gum ranges from 20×10 6 to 100×10 6 centipoise at 25° C. and wherein the vinyl concentration of the gum varies from 0.5 to 15.0 mole percent.

Claim 33

Dependent Claim 19 words

The article of claim 29 wherein R 2 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation.

Claim 34

Dependent Claim 31 words

The article of claim 25 wherein there is present from 10 to 200 parts by weight of a reinforcing filler selected from the group consisting of fumed silica and precipitated silica.

Claim 35

Dependent Claim 17 words

The article of claim 31 wherein an extending filler is utilized in addition to the reinforcing filler.

Claim 36

Dependent Claim 23 words

The article of claim 25 wherein the reinforcing filler is treated with treating agents selected from the class consisting of cyclopolysiloxanes and silazanes.

Claim 37

Dependent Claim 14 words

The article of claim 25 wherein the curing agent is selected from organic peroxides.

Claim 38

Dependent Claim 20 words

The article of claim 34 wherein the curing agent is selected from the group consisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide and 5-butylcumylperoxide.

Claim 39

Dependent Claim 20 words

The article of claim 25 further comprising from 1 to 500 parts per million of a platinum catalyst cure accelerator.

Claim 40

Dependent Claim 64 words

The article of claim 25 wherein the hydride-containing polysiloxane is a linear polysiloxane of the formula, ##STR14## where R 5 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation, p and q vary such that the viscosity of the hydride polysiloxane ranges from 10 to 1000 centipoise at 25° C. and the hydride content varies from 0.05 to 2.0 percent by weight.

Claim 41

Dependent Claim 61 words

The article of claim 25 where the hydride containing polysiloxane is a hydride resin having ##STR15## and SiO 2 units where R 6 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation and the R 6 +H to Si ratio varies from 1.0 to 2.7 wherein the hydride content of the resin varies from 0.05 to 2.0 weight percent.

Claim 42

Dependent Claim 53 words

The article of claim 25 wherein the hydride-containing polysiloxane is a hydride resin having ##STR16## and SiO 2 units and (R 6 ) 2 SiO units where the R 6 +H to Si ratio varies from 1.2 to 2.7 and R 6 is a C 1-8 monovalent hydrocarbon radical free of aliphatic unsaturation.

Claim 43

Dependent Claim 32 words

The article of claim 25 wherein the curing agent is present at a concentration of at least 0.1 parts by weight per 100 parts by weight of the rest of the composition.

Claim 44

Dependent Claim 85 words

The article of claim 25 further comprising from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R.sub.3.sup.8 --SiO.sub.0.5 units and SiO 2 units where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation with a ratio of R 3 8 SiO 0 .5 units to SiO 2 units ranging from about 0.5 to 1 to 1 to 1, and where said copolymer contains about 2.5 to 10 mole percent vinyl groups.

Claim 45

Dependent Claim 123 words

The article of claim 25 further comprising from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R.sub.3.sup.8 --SiO.sub.0.5 units and SiO.sub.2 units and R.sub.2.sup.8 --SiO units where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of R 3 8 --SiO 0 .5 units to SiO 2 units is from about 0.5 to 1 to 1 to 1, and the R 2 8 --SiO units are present in an amount of from about 1 to 10 mole percent based on the total number of moles of siloxy units in the copolymer, and where the resinous copolymer contains from about 2.5 to 10.0 mole percent vinyl groups.

Claim 46

Dependent Claim 18 words

The article of claim 25 further comprising from 1 to 25 parts by weight of a process aid.

Claim 47

Dependent Claim 74 words

The article of claim 43 wherein the process aid is a dihydrocarbon substituted polysiloxane oil having a hydrocarbon substituent silicon atom ratio from 1.0 to 2.0 and where such hydrocarbon substituents comprise at least one member selected from the class consisting of methyl, vinyl, ethyl, allyl, cyclohexenyl and phenyl groups, said polysiloxane oil comprising polysiloxane molecules containing an average from 1 to 2 lower alkoxy groups bonded to each of the terminal silicon atoms.

Claim 48

Dependent Claim 11 words

The article of claim 34 wherein the curing agent is 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3.

Claim 49

Dependent Claim 50 words

The article of claim 43 wherein the process aid is a hydroxylated organosiloxane, a hydroxylated silane or mixtures thereof, said process aid containing on average from 1.9 to 2.1 hydrocarbon radicals per silicon atom and from 1 silicon-bonded OH per 70 silicon atoms to 2 silicon-bonded OH per silicon atom.

Claim 50

Dependent Claim 31 words

The article of claim 25 wherein the curing agent is present in a concentration of from 0.1 to 2 parts by weight per 100 parts of the rest of the composition.

Claim 51

Dependent Claim 14 words

The process of claim 24 wherein the curing agent is selected from organic peroxides.

Claim 52

Dependent Claim 20 words

The process of claim 48 wherein the curing agent is selected from the group consisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide and 5-butylcumylperoxide.

Claim 53

Dependent Claim 24 words

The process of claim 24 further comprising mixing from 1 to 500 parts per million of a platinum catalyst curing accelerator into the mixture.

Claim 54

Dependent Claim 27 words

The process of claim 24 wherein the curing agent is present at a concentration of at least 0.1 parts by weight per 100 parts by weight composition.

Claim 55

Dependent Claim 91 words

The process of claim 24 further comprising mixing from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R 3 8 SiO 0 .5 units and SiO 2 units, where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation and having a ratio of R 3 8 SiO 0 .5 units to SiO 2 units ranging from about 0.5 to 1 to 1 to 1, and where said copolymer contains about 2.5 to 10 mole percent vinyl groups.

Claim 56

Dependent Claim 130 words

The process of claim 24 further comprising mixing from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R 3 8 SiO 0 .5 units, SiO 2 units and R 2 8 SiO units, where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of R 3 8 SiO 0 .5 units to SiO 2 units is from about 0.5 to 1 to 1 to 1 and the R 2 8 SiO units are present in an amount of from about 1 to 10 mole percent based on the total number of moles of siloxy units in the copolymer, and where the resinous copolymer contains from about 2.5 to 10.0 mole percent vinyl groups.

Claim 57

Dependent Claim 20 words

The process of claim 24 further comprising mixing from 1 to 25 parts of a process aid into the mixture.

Claim 58

Dependent Claim 29 words

The process of claim 24 wherein the curing agent is present in a concentration of from about 0.1 to 2 parts by weight per 100 parts by weight composition.

Claim 59

Independent Claim 222 words

A method of making an elastomeric silicone article comprising: (i) mixing: (A) 60-95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent, and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl content in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of a filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of a hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having an organic peroxide viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of a free radical initiator curing agent; (ii) forming the mixture of step (i) into the desired shape; and (iii) heating the shaped composition at an elevated temperature in order to effect curing of the composition.

Claim 60

Independent Claim 222 words

A method of making an elastomeric silicone article comprising: (i) mixing: (A) 60-95 parts by weight of a vinyl-terminated linear diorganopolysiloxane gum having a viscosity in the range of 1×10 6 to 20×10 7 centipoise at 25° C. and having a vinyl concentration in the range of 0.005 to 0.1 mole percent, and where the organo groups are monovalent hydrocarbon radicals; (B) 5.0 to 40.0 parts by weight of a vinyl-containing diorganopolysiloxane gum having a viscosity in the range of 20×10 6 to 100×10 6 centipoise at 25° C. and having a vinyl content in the range of 0.5 to 15.0 mole percent, wherein the organo groups are monovalent hydrocarbon radicals and the sum of (A) and (B) equals 100 parts by weight; (C) 10 to 300 parts by weight of a filler, at least part of which is a reinforcing silica filler; (D) 0.1 to 25 parts by weight of a hydride-containing polysiloxane having a hydride content ranging from 0.05 to 5.0 percent by weight and having an organic peroxide viscosity ranging from 10 to 1000 centipoise at 25° C.; and (E) an effective amount of a free radical initiator curing agent; (ii) forming the mixture of step (i) into the desired shape; and (iii) heating the shaped composition at an elevated temperature in order to effect curing of the composition.

Claim 61

Dependent Claim 14 words

The method of claim 56 wherein the curing agent is selected from organic peroxides.

Claim 62

Dependent Claim 20 words

The method of claim 57 wherein the curing agent is selected from the group consisting of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, di-t-butylperoxide and 5-butylcumylperoxide.

Claim 63

Dependent Claim 26 words

The method of claim 56 further comprising mixing 1 to 500 parts per million of a platinum catalyst curing accelerator into the mixture of step (i).

Claim 64

Dependent Claim 27 words

The method of claim 56 wherein the curing agent is present in a concentration of at least 0.1 parts by weight per 100 parts by weight composition.

Claim 65

Dependent Claim 94 words

The method of claim 56 further comprising mixing in step (i) from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R 3 8 SiO 0 .5 units and SiO 2 units, where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation and having a ratio of R 3 8 SiO 0 .5 units to SiO 2 units ranging from about 0.5 to 1 to 1 to 1, and where said copolymer contains about 2.5 to 10 mole percent vinyl groups.

Claim 66

Dependent Claim 131 words

The method of claim 56 further comprising mixing in step (i) from 1 to 50 parts by weight of an organopolysiloxane resin copolymer comprising R 3 8 SiO 0 .5 units, SiO 2 units and R 2 8 SiO units, where R 8 is selected from the group consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of R 3 8 SiO 0 .5 units to SiO 2 units is from about 0.5 to 1 to 1 to 1 and the R 2 8 SiO units are present in an amount of from about 1 to 10 mole percent based on the total number of siloxy units in the copolymer, and where the resinous copolymer contains from about 2.5 to 10.0 mole percent vinyl groups.

Claim 67

Dependent Claim 20 words

The method of claim 56 further comprising mixing in step (i) from 1 to 25 parts of a process aid.

Claim 68

Dependent Claim 28 words

The method of claim 56 wherein the curing agent is present in a concentration of from 0.1 to 2 parts by weight per 100 parts by weight composition.

Claim 69

Dependent Claim 16 words

The method of claim 56 wherein curing is effected at a temperature greater than 100° C.

Claim 70

Dependent Claim 14 words

The method of claim 56 further comprising the step of post curing the article.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1988-09-02	1989-03-04	1989-09-03	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1992-09-02	1993-03-04	1993-09-03	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1996-09-02	1997-03-04	1997-09-03	$7700.00	Window Closed / Lapsed

Peroxide curing polysiloxane compositions having a high tear strength

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