Dow Corning Corporation

Joseph T Braun

Joseph Norbert Clark

Shawn K Mealey

Virgil J Johnson

Schuyler B Smith

William J Schoenherr

Peter Lamont

Madhu Baile

Edward Joseph Benson

The instant invention pertains to a method of producing silicone pressure sensitive adhesives wherein the method comprises (I) combining together (A) a benzene soluble, hydroxyl containing organopolysiloxane resin consisting essentially of R.sub.3 SiO.sub.1/2 siloxane units and SiO.sub.4/2 siloxane units, wherein R is a monovalent radical selected from the group consisting of hydrocarbon and halogenated hydrocarbon radicals having from 1 to 10 carbon atoms; there being from 0.5 to 1.5 R.sub.3 SiO.sub.1/2 units for every SiO.sub.4/2 units and there being 1.0 to 4 wt %, based on FTIR, hydroxyl functionality and (B) a hydroxyl containing polydiorganosiloxane having a viscosity of .gtoreq.100 mPa's and (C) a catalyst selected from the group consisting of a weak organic acid or metal salt thereof; and thereafter (II) heating the mixture of (A), (B) and (C) for a time sufficient to produce the silicone pressure sensitive adhesive.

Method of making silicone pressure sensitive adhesives

A pressure sensitive adhesive tape comprising a tape substrate having at least a portion of one or more sides coated with a silicone pressure sensitive adhesive is constructed using an adhesive which cures to a permanent adhesive. The adhesive is covered on the outer side with a release film, preferably coated with a fluorosilicone release layer, to allow storage of the tape. Preferably the curable silicone pressure sensitive adhesive is cured upon exposure to moisture, the tape therefore being stored in the absence of moisture. A silicone elastomeric structural glazing tape is made by using a silicone elastomer as the tape substrate. The tape can be used to bond glazing panels to building components without the use of other means of fastening.

Curable silicone pressure sensitive adhesive tape and bonding method

Moisture-curable silicone pressure sensitive adhesives can be covered with an addition-cured fluorosilicone release coating to provide a releasable laminate. The release force of the laminate is low to moderate and the subsequent adhesion and tack of the adhesive is high and all three values are stable with time. The laminate can be prepared by contacting the release coating with solvent-free or solvent-containing adhesive

Laminate article comprising moisture-curable silicone pressure sensitive

Improved primer compositions comprise (A) at least one member of a specified group of ethylenically unsaturated organosilicon compounds containing silicon-bonded alkoxy groups, (B) silicone/organic copolymers prepared from esters of ethylenically unsaturated organic acids and organosilicon compounds derived from these acids, (C) organohydrogensiloxane curing agents and (D) a solvent. The improvement resides in the presence in the solvent of an ethylenically unsaturated alcohol containing from 4 to 6 carbon atoms. The alcohol constitutes at least 50 percent by weight of the solvent.

Primer compositions

A silicone crumb in a fine particulate form has an extrusion rate of at least 50 grams per minute through an orifice of 0.5 inch diameter under a pressure of 345 kilopascals and compression points of less than 1035 kilopascals. This crumb is made from a vinyl-containing polyorganosiloxane, a silicon-bonded hydrogen containing polysiloxane, a platinum catalyst, and a heat stability additive compound containing zirconium, titanium, or hafnium and organosiloxane. The crumb is useful in hydraulic applications where it is exposed to temperatures above 500.degree. F. for prolonged periods of time.

Hydraulic silicone crumb with improved heat stability

A method of preparing a copolymer of methyl(2-phenylpropyl)siloxy units and dialkylsiloxy units is disclosed. The method hydrolyzes methyl(2-phenylpropyl)dichlorosilane to yield a reaction product of primarily methyl(2-phenylpropyl)disiloxanediol, then copolymerizes the reaction product with dialkylcyclosiloxane to give the copolymer. The copolymer has a crystallinity point of less than -50.degree. C. It is useful in producing silicone elastomers and sealants having a comparably low crystallinity point.

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Midland, MI, United States of America

Joseph T Braun