A sealant material for sealing threaded pipe joints that is a multifilament or spun polyphenylene sulfide yarn and a joint sealing composition comprising a silicone oil or a natural oil with a smoke point of about 230 C. or higher. The polyphenylene sulfide yarn is coated with the joint sealant composition. The material forms an effective seal and is resistant even when used in systems in which it is exposed to temperatures in excess of 280 C. The material may be provided in a dispenser.

The present invention provides: a room temperature curable organopolysiloxane composition which has curability equivalent to the curability of conventional dealcoholization type or deoximation type room temperature curable organopolysiloxane compositions even if various catalysts are used therefor, while reducing harmful effects on human bodies and burden on the environment, and which enables the achievement of a cured product that has good rubber properties, adhesiveness and durability if cured; various articles which comprise this composition or a cured product that is obtained by curing this composition; a novel hydrolyzable organosilane compound which is useful as a curing agent for this composition; and a method for producing this novel hydrolyzable organosilane compound. A room temperature curable organopolysiloxane composition which contains, as a curing agent, a hydrolyzable organosilane compound that is represented by general formula (2) and releases/discharges a cyclic ketone compound as a leaving group and/or a partial hydrolysis-condensation product of the hydrolyzable organosilane compound.

##STR00001##

(In the formula, R.sup.2 represents a monovalent hydrocarbon group having from 1 to 10 carbon atoms; n represents a number from 1 to 8; and m represents 3 or 4.)

Provided is a curable organopolysiloxane composition from which highly heat-resistant cured products can be obtained, the curable organopolysiloxane composition comprising: (A) 100 parts by mass of a novel organopolysiloxane represented by formula (1) ##STR00001##
(R.sup.1 is an alkyl group or an alkoxy substituted alkyl group having 1 to 6 carbon atoms, R.sup.2 is a group selected from an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and a group in which a portion of the hydrogen atoms of those groups is substituted with a halogen atom, Ar is an arylene group having 6 carbon atoms or more, a is 1 to 1,000, b is 1 to 5,000, and n is 1 to 3, the total of n in an unsubstituted or substituted alkoxysilyl group on both ends of the molecular chain being 3 or more); and (B) 0.01 to 10 parts by mass of a curing catalyst. Also provided are electrical and electronic components, a vehicle oil seal, a building sealant, etc. which use the cured product of the composition.

Process for producing PU foams by reacting at least one polyol component with at least one isocyanate component in the presence of one or more catalysts that catalyse the isocyanate-polyol and/or isocyanate-water reactions and/or isocyanate trimerization, and optionally one or more chemical or physical blowing agents, with use of SiOC-bonded polyether siloxanes having branching in the siloxane moiety, prepared from branched siloxanes bearing acetoxy groups, wherein a sufficient amount of the SiOC-bonded polyether siloxane having branching in the siloxane moiety is added that the proportion by mass of this polyether siloxane (e) based on the finished PU foam is from 0.0001% to 10% by weight.

Provided are a novel acrylic polymer that has moderate crosslinking reactivity and is suitable for sealant applications and a sealant using the polymer. The (meth)acrylic acid alkyl ester polymer according to the invention has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) method of 30,000 to 150,000 and a number average molecular weight (Mn) of less than 20,000 and has 1.1 to 3.0 methyldimethoxysilyl groups, more than 0.5 methyldimethoxysilyl groups at side chains of a molecular chain, and more than 0.5 methyldimethoxysilyl groups at molecular chain terminals, per one molecule of the polymer.

A two part curable composition comprising organosiloxane polymer; water; an organosilane such as hexamethyldisilazane (HMDS) or vinyltrimethoxysilane; crosslinker; adhesion promoter and catalyst; and optionally comprising plasticizer; colorant and filler. The first part can comprise organosiloxane polymer and water. The second part can comprise crosslinker; adhesion promoter and catalyst. Either or both parts can optionally further comprise an organosilane such as hexamethyldisilazane (HMDS) or vinyltrimethoxysilane; plasticizer; colorant and filler. Cured reaction products of the two part curable organosiloxane composition has good adhesion to metallic sealing surfaces and good resistance engine oil and other automotive fluids. Cured reaction products of the two part curable organosiloxane composition can surprisingly retain physical properties after long-term exposure to temperatures between 200 C. and 250 C. and can retain physical properties after exposure to temperatures between 250 C. to 300 C. for short periods.

The invention provides a composition capable of providing a molded article that has excellent heat resistance and a small weight change against oxygen plasma exposure and fluorine plasma exposure during a semiconductor manufacturing step. The composition contains a fluorine-containing polymer and a hyperbranched polymer of a cage silsesquioxane with a specific structure.

The present invention relates to a hydrosilylation-curable silicone composition comprising: a maleate compound, and a hydrosilylation inhibitor other than the maleate compound, wherein the content of the maleate compound is in an amount of 50 to 6,000 ppm and the content of the hydrosilylation inhibitor is in an amount of 200 to 20,000 ppm, with respect to the present composition in terms of mass units, respectively. The hydrosilylation-curable silicone composition exhibits good storage stability, and can be cured to form a cured product that suffers no surface wrinkling.

An isocyanate-functional silicone-polyether copolymer having a particular structure is disclosed. A method of preparing the isocyanate-functional silicone-polyether copolymer is also disclosed, the method comprising reacting a polyether compound and an organosilicon compound to give the isocyanate-functional silicone-polyether copolymer. A silicone-polyether-urethane copolymer formed therewith, as well as a method of preparing the silicone-polyether-urethane copolymer, are also disclosed. Sealants comprising the isocyanate-functional silicone-polyether copolymer and/or the silicone-polyether-urethane copolymer are further disclosed.

A silicone-polyether copolymer has the formula XY, where X is a silicone moiety having a particular structure and Y is a polyether moiety. An isocyanate-functional silicone-polyether copolymer formed therewith is also disclosed. Further, a silicone-polyether-urethane copolymer formed with the isocyanate-functional silicone-polyether copolymer is disclosed. Related methods of preparation as well as sealants and cured products thereof are further disclosed.