Claims
- 1. A curable organosiloxane resin composition, curable to a rigid resin which exhibits optical transparency in the crosslinked state, said composition comprising
- A. a first organosiloxane resin comprising 1) at least two of a first reactive group per molecule and 2) siloxane units of the average formula R.sub.n SiO.sub.(4-n)/2, wherein each R is individually selected from the group consisting of alkyl radicals containing from 1 to 18 carbon atoms, alkenyl and aryl radicals, and the value of n is greater than 0 and less than 2;
- B. a second organosiloxane resin comprising at least two of a second reactive group per molecule which reacts with said first reactive group to form a crosslinked resin, and siloxane units of the average formula R'.sub.m SiO.sub.(4-m)/2, wherein each R' is individually selected from the same group as R, and the value of m is greater than 0 and less than 2, and
- C. from 0.5 to 100 weight percent, based on the combined weights of said first and second resins, of a reinforcing silica exhibiting an average particle size of less than one micron.
- 2. A curable organosiloxane resin composition according to claim 1 wherein the hydrocarbon radicals represented by R and R' and the values of m and n provide a crosslinked resin exhibiting an index of refraction at a wavelength of 587.6 nm of from 1.410 to 1.460 and a variation of refractive index with temperature of less than 1.times.10.sup.-3 per degree centigrade.
- 3. A resin composition according to claim 1, wherein n and m are each greater than 1 and less than 1.8, each R and R' in each of said units is individually selected from the group consisting of methyl, phenyl and vinyl radicals and the viscosity of said first and second resins is from 10 to 100,000 cP (0.01 to 100 Pa.s) within the temperature range wherein said resins are liquid.
- 4. A resin composition according to claim 3 wherein each molecule of said first resin contains two or more alkenyl radicals and each molecule of said second resin contains two or more silicon-bonded hydrogen atoms.
- 5. A resin composition according to claim 4, wherein the crosslinked resin obtained by curing said composition exhibits a transmittance of at least 70 percent for light in the range from 400 nm to 850 nm and a variation of refractive index with temperature of less than 10.sup.-3 per degree Centigrade.
- 6. A resin composition according to claim 1, wherein the viscosity of said first resin is from 100 to 10,000 cP (0.1 to 10 Pa.s).
- 7. A resin composition according to claim 1, wherein the viscosity of said second resin is from 100 to 10,000 cP (0.1 to 10 Pa.s).
- 8. A method for preparing an crosslinked, optically transparent organosiloxane resin, said method comprising the sequential steps of
- I. blending to homogeneity
- A. a first organosiloxane resin comprising 1) at least two of a first reactive group per molecule and 2) siloxane units of the average formula R.sub.n SiO.sub.(4-n)/2, wherein each R is individually selected from the group consisting of alkyl radicals containing from 1 to 18 carbon atom, alkenyl and aryl radicals, and the value of n is greater than 0 and less than 2;
- B. a second organosiloxane resin comprising 1) at least two of a second reactive group per molecule which reacts with said first reactive group to form a crosslinked resin that is a solid at 25 degrees C., and 2) siloxane units of the average formula R'.sub.m SiO.sub.(4-m)2, wherein each R' is individually selected from the same group as R, and m is selected from the same group as n, and
- C. from 0.5. to 100 parts by weight, based on the combined weights of said first and second resins, of a reinforcing silica exhibiting an average particle size of less than one micron,
- II. curing said composition to yield an optically transparent crosslinked resin that is a solid a 25.degree. C.
- 9. A method according to claim 8 wherein the hydrocarbon radicals represented by R and R' and the values of m and n are selected to achieve a crosslinked resin exhibiting an index of refraction at a wavelength of 587.6 nm of from 1.410 to 1.460 and a variation of the refractive index with temperature of less than 1.times.10.sup.-3 per degree centigrade.
- 10. A method according to claim 8, wherein n and m are each greater than 1 and less than 1.8, each R and R' in each of said units is individually selected from the group consisting of methyl, phenyl and vinyl radicals and the viscosity of said first and second resins is from 10 to 100,000 cP (0.01 to 100 Pa.s) within the temperature range wherein said resins are liquid.
- 11. A method according to claim 10 wherein each molecule of said first resin contains two or more alkenyl radicals and each molecule of said second resin contains two or more silicon-bonded hydrogen atoms.
- 12. A method according to claim 11, wherein the crosslinked resin obtained by curing said composition exhibits a transmittance of at least 70 percent for light in the range from 400 nm to 850 nm and a variation of refractive index with temperature of less than 10.sup.-3 per degree centigrade.
- 13. A resin composition according to claim 7, wherein the viscosity of said first resin is from 100 to 10,000 cP (0.1 to 10 Pa.s).
Priority Claims (1)
Number |
Date |
Country |
Kind |
6-83100 |
Apr 1994 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 08/427,177 filed Apr. 21, 1995 which application is now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
4882398 |
Mbah |
Nov 1989 |
|
Non-Patent Literature Citations (1)
Entry |
Handbook of Fillers and Reinforcements for Plastics, Van Nostrand Reinhold Co., pp. 138-143, 1978. |
Continuations (1)
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Number |
Date |
Country |
Parent |
427177 |
Apr 1995 |
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