Dow Corning Corporation

Pierre Maurice Chevalier

Duan Li Ou

Bizhong Zhu

Russell Keith King

Duane R Bujalski

Kai Su

Katsuya Eguchi

Ronald Paul Boisvert

Yeong Joo Lee

John Albaugh

Iain A MacKinnon

Steven Robson

Genevieve Marie-Louise Emile Cerveau

Bertrand Francois Dabiens

Robert Jean-Pierre Corriu

Anne Dupont

A polysiloxane having a refractive index of about 1.56 measured at light wavelength 633 nm, characterized in that the polysiloxane includes siloxane T units of the formula where A represents an alkylene group having 1 to 4 carbon atoms: n=0 or 1; m is at least 1; and Ar is an aryl group substituted by at least one iodine, bromine or chlorine atom, or is a polynuclear aromatic group. The invention includes chlorosilanes having the formula (Ar) m-(A)nSiCl3, useful in forming high refractive index polysiloxanes.

High refractive index polysiloxanes and their preparation

A silicone resin, curable to a resin of low coefficient of thermal expansion, high glass transition temperature and high modulus, has the empirical formula(RSiO)(RSiO)(RSiO)(SiO)wherein each R is a hydrocarbon or substituted hydrocarbon group or a hydrogen atom; and a=0.02 to 0.8; b=0 to 0.4; and c+d=0.2 to 0.98, where a+b+c+d=1.0, characterized in that at least 2 mole % of the siloxane units in the resin are of the formula R'SiO, RR&#x2032;SiOor R&#x2032;SiO, wherein each R&#x2032; is an alkenyl group.

Silicone resins

A curable silicone resin composition comprises (A) an uncured silicone resin having units of the formula (R*) (R) SiO , where each R* is a functional group capable of reacting with Si&mdash;OH and/or Si-alkoxy groups and each R is a nonfunctional monovalent hydrocarbon group, a&plus;b is from 1.0 to 3.0 and each molecule of uncured silicone resin contains an average of at least two groups R*, and (B) a silanol or hydrolysable compound of the formula (I) where R&prime; represents a hydroxyl group or a hydrolysable group; each R&Prime; represents hydrogen, a monovalent hydrocarbon which optionally is substituted, or a group within the above definition of R&prime;; and Ar is a substantially nonflexible linkage including at least one para-arylene moiety, so that the groups (R&prime;) R&Prime;Si&mdash; are spatially separated.

Curable silicone resin composition and reactive silicon compounds

This invention pertains to a siloxane resin composition comprising R SiO siloxane units, R SiO siloxane units and (R O) SiO siloxane units wherein R is an alkyl group having 1 to 5 carbons, hydrogen, or mixtures thereof; R is a monovalent organic group having 6 to 30 carbons; R is a branched alkyl group having 3 to 30 carbons, b is from 1 to 3; and the siloxane resin contains from 2.5 to 85 mole percent R SiO units, 2.5 to 50 mole percent R SiO units and 5 to 95 mole percent (R O) SiO units. The siloxane resin is useful to make insoluble porous resin and insoluble porous coatings. Heating a substrate coated with the siloxane resin at a sufficient temperature effects removal of the R and R O groups to form an insoluble insoluble porous coating having a porosity of 1 to 60 volume percent and a dielectric constant in the range of 1.5 to 3.0.

Siloxane resins

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Penarth, United Kingdom

Pierre Maurice Chevalier