Epoxy-Functional Polysiloxanes, Silicone Composition, and Coated

a technology of polysiloxanes and polysiloxanes, applied in the field of polysiloxanes with polyfunctional properties, can solve the problems of fibers being susceptible to irreversible environmental degradation, time-consuming and expensive, and difficult to cure, and achieves good shelf-stability, low absorbance, and rapid cure

Inactive Publication Date: 2008-10-23
DOW CORNING CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0019]The epoxy-functional polysiloxanes of the present invention have very low absorbance in the ultraviolet region of the electromagnetic spectrum and good shelf-stability. Moreover, the polysiloxanes contain highly reactive epoxy groups and can be cured rapidly to produce durable cross-linked polysiloxanes.
[0020]The silicone composition of the present invention can be conveniently formulated as a one-part composition having good shelf-stability in the absence of ultraviolet light. Moreover, the composition can be applied to a substrate by conventional high-speed methods such as spin coating, in-line optical fiber coating, printing, and spraying. Furthermore, the silicone composition cures rapidly upon exposure to ultraviolet light.
[0021]The cured polysiloxane prepared by exposing the silicone composition to ultraviolet radiation exhibits high transparency, typically at least 70% transmittance, alternatively at least 80% transmittance, alternatively at least 85%, at a wavelength of 248 nm for a free-standing film (i.e., without a substrate) having a thickness of 60 μm. Moreover, the cured polysiloxane has good primerless adhesion to a variety of substrates. The cured polysiloxane also exhibits excellent durability, chemical resistance, and flexibility at low temperatures.
[0022]The coated optical fiber of the present invention exhibits good resistance to abrasion, organic solvents, water vapor, and oxygen. Moreover, the coated optical fiber has good thermal stability and mechanical strength.
[0023]The method of preparing the coated optical fiber of the present invention is scaleable to a high throughput manufacturing process. Also, the method employs conventional optical fiber fabrication techniques (e.g., coating and curing) and equipment. Importantly, the method can further comprise writing at least one Bragg grating on the core of the fiber directly through the silicone coating, thereby eliminating conventional stripping and recoating operations and the problems associated therewith.

Problems solved by technology

However, because most protective coatings are not transparent to ultraviolet light at the wavelengths (e.g., 193 nm and 240 nm) commonly used to write gratings, the coating must be removed before exposing the core to ultraviolet light.
These stripping and coating operations are problematic, time-consuming, and expensive.
For example, once stripped of the protective coating the fiber is susceptible to irreversible environmental degradation caused by humidity and debris.

Method used

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  • Epoxy-Functional Polysiloxanes, Silicone Composition, and Coated

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0114]Dimethylcyclosiloxanes (267.3 g, ˜3.61 mol of D4), 216.6 g (˜3.61 mol of DH4) of Methylhydrogencyclosiloxanes, and 9.97 g (0.074 mol) of 1,1,3,3-tetramethyldisiloxane were combined in a flask equipped with a condenser, agitator, and heating mantle. The mixture was treated with 5 g of Tonsil® Optimum clay catalyst. The mixture was heated to 65° C. with agitation and kept at this temperature for 2 h. The mixture was then heated to 80° C. and kept at this temperature until equilibrium was reached, as indicated by a constant ratio of cyclosiloxanes to linear polysiloxane in the 29Si NMR spectrum of the mixture. The mixture was allowed to cool to room temperature and then filtered through Grade 4 Whatman® filter paper to remove the catalyst. The filtrate was stripped (distilled) at 130° C. and 0.1 mm Hg (13.3 Pa) to remove most of the cyclosiloxanes. The residue consisted of a dimethylhydrogensiloxy-terminated poly[dimethylsiloxane-co-(methylhydrogensiloxane)] having the formula HM...

example 2

[0115]1-Octene (43.33 g, 0.39 mol) and 47.94 g (0.39 mol) of 4-vinyl-1-cyclohexene 1,2-epoxide were combined in a flask equipped with an agitator, thermometer, and addition funnel. The mixture was heated to 70° C. and 3.83 g of platinum (0.5%) on alumina was added to the flask. The dimethylhydrogensiloxy-terminated poly[dimethylsiloxane-co-(methylhydrogensiloxane)] of Example 1 (100 g, 0.77 mol silicon-bonded hydrogen atoms) was added to the mixture at such a rate as to keep the temperature below 100° C. The progress of the reaction was monitored by periodically withdrawing an aliquot of the mixture for FT-IR analysis. When the Si—H absorption at 2100-2200 cm−1 was no longer evident, the mixture was allowed to cool to room temperature. The mixture was filtered through a membrane (1 μm) to remove the catalyst, and the filtrate was passed through a Pope Wiped-Film Still at a temperature of 120° C. and pressure of 0.05 mm Hg (6.7 Pa) to give an epoxy-functional polysiloxane having the ...

example 3

[0116]An epoxy-functional polysiloxane having the formula:

where R is —C8H17 or

m is 54, n is 36, and p is 15, as determined by 29Si NMR, was prepared according to the method of Example 2, except 69.81 g (0.62 mol) of 1-octene and 23.41 g (0.1885 mol) of 4-vinyl-1-cyclohexene 1,2-epoxide were used in the reaction. In the preceding formula the subscripts m, n, and p denote mole fractions, which are based on the total number of moles of repeat (non-terminal) siloxane units in the polysiloxane. The polysiloxane was obtained as an colorless fluid having a refractive index, η20D, of 1.4689 and a viscosity of 578 cS (578 mm2 / s).

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Abstract

Epoxy-functional polysiloxanes containing epoxy groups and hydrocarbyl groups free of aliphatic unsaturation, a silicone composition containing a polysiloxane selected from the aforementioned epoxy-functional polysiloxanes, a cured polysiloxane prepared by exposing the silicone composition to ultraviolet radiation, a coated optical fiber containing a cured polysiloxane, and a method of preparing a coated optical fiber.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This application claims the benefit of U.S. Provisional Patent Application No. 60 / 670,364 filed 12 Apr. 2005 under 35 U.S.C. §119 (e). U.S. Provisional Patent Application No. 60 / 670,364 is hereby incorporated by reference.FIELD OF THE INVENTION[0002]The present invention relates to epoxy-functional polysiloxanes and more particularly to epoxy-functional polysiloxanes containing epoxy groups and hydrocarbyl groups free of aliphatic unsaturation. The present invention also relates to a silicone composition containing a polysiloxane selected from the aforementioned epoxy-functional polysiloxanes, a cured polysiloxane prepared by exposing the silicone composition to ultraviolet radiation, a coated optical fiber containing a cured polysiloxane, and a method of preparing a coated optical fiber.BACKGROUND OF THE INVENTION[0003]Coated optical fibers typically have at least three components: a core, a cladding surrounding the core, and a protectiv...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): G02B6/02C08G77/04C08L83/04G02B6/028C03B37/01
CPCC03C25/106C08G77/14C08G77/38Y10T428/2962C08L83/06C08L2666/46C08G77/04C08L83/04C03C25/36
Inventor BAHADUR, MANEESHGLOVER, SHEDRIC O'NEALNORRIS, ANN WALSTROM
Owner DOW CORNING CORP
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