Abstract: The present disclosure relates to aqueous gelling systems comprising an encapsulated polymerization accelerator with water soluble or dispersable monomers comprising acrylated or methacrylated polyethylene and/or polyoxypropylene monomers and a polymerization initiator dispersed in said monomers, useful i.a. for sealing subterranean environments or consolidation of a soil or sealing of a subterranean structure.

Abstract: The invention relates to a method for producing a (meth)acrylic anhydride A-C(?O)—O—(O?)C-A, comprising the following steps: a) a step of reacting an anhydride B—C(?O)—O—(O?)C—B with an acid A-COOH, resulting in the formation of mixed anhydride A-C(?O)—O—(O?)C—B and acid B—COOH; and b) a step of reacting the mixed anhydride with A-COOH, resulting in the (meth)acrylic anhydride. According to the invention, reaction steps (a) and (b) are carried out in the presence of hydrated triflic acid, and the anhydride A-C(?O)—O—(O?)C-A is isolated from the reaction medium produced in step (b) as follows: e1) heavy compounds having a volatility less than or equal to that of the anhydride A-C(?O)—O—(O?)C-A are separated from the reaction medium, said compounds including the anhydride and the hydrated triflic acid; e2) the anhydride is separated from the heavy compounds by difference in volatility.

Abstract: A process allowing the encapsulation of a polymerization accelerator comprising the steps of: a) providing an reverse emulsion containing, in an oil phase, a water solution/dispersion containing the polymerisation activator, the oil phase including a heat curable mixture of an isocyanate and a polyalkyldiene hydroxylated or polyol, b) pouring the reverse emulsion in a water phase to make a multiple emulsion water/oil/water, containing drops of activators as the internal water phase, and then, c) heating the multiple emulsion obtained in step b) to cure the polyisocyanate in polyurethane and obtain drops of activator enclosed in shells of polyurethane dispersed in water. The invention also relates to aqueous gelling systems comprising the encapsulated polymerization accelerator with water soluble or dispersable monomers and a polymerization initiator dispersed in said monomers, useful i.a. for sealing subterranean environments or consolidation of a soil or sealing of a subterranean structure.

Abstract: A process allowing the encapsulation of a polymerization accelerator comprising the steps of: a) providing an reverse emulsion containing, in an oil phase, a water solution/dispersion containing the polymerization activator, the oil phase including a heat curable mixture of an isocyanate and a polyalkyldiene hydroxylated or polyol, b) pouring the reverse emulsion in a water phase to make a multiple emulsion water/oil/water, containing drops of activators as the internal water phase, and then, c) heating the multiple emulsion obtained in step b) at a temperature of between 50 and 95° C., in order to cure the polyisocyanate in polyurethane and obtain drops of activator enclosed in shells of polyurethane dispersed in water. The invention also relates to aqueous gelling systems comprising the encapsulated polymerization accelerator with water soluble or dispersable monomers and a polymerization initiator dispersed in said monomers, useful i.a.

Abstract: The invention relates to a method for producing a (meth)acrylic anhydride A-C(?O)—O—(O?)C-A, comprising the following steps: a) a step of reacting an anhydride B—C(?O)—O—(O?)C—B with an acid A-COOH, resulting in the formation of mixed anhydride A-C(?O)—O—(O?)C—B and acid B—COOH; and b) a step of reacting the mixed anhydride with A-COOH, resulting in the (meth)acrylic anhydride. According to the invention, reaction steps (a) and (b) are carried out in the presence of hydrated triflic acid, and the anhydride A-C(?O)—O—(O?)C-A is isolated from the reaction medium produced in step (b) as follows: e1) heavy compounds having a volatility less than or equal to that of the anhydride A-C(?O)—O—(O?)C-A are separated from the reaction medium, said compounds including the anhydride and the hydrated triflic acid; e2) the anhydride is separated from the heavy compounds by difference in volatility.

Abstract: A process allowing the encapsulation of a polymerization accelerator comprising the steps of: a) providing an reverse emulsion containing, in an oil phase, a water solution/dispersion containing the polymerisation activator, the oil phase including a heat curable mixture of an isocyanate and a polyalkyldiene hydroxylated or polyol, b) pouring the reverse emulsion in a water phase to make a multiple emulsion water/oil/water, containing drops of activators as the internal water phase, and then, c) heating the multiple emulsion obtained in step b) at a temperature of between 50 and 95° C., in order to cure the polyisocyanate in polyurethane and obtain drops of activator enclosed in shells of polyurethane dispersed in water. The invention also relates to aqueous gelling systems comprising the encapsulated polymerization accelerator with water soluble or dispersable monomers and a polymerization initiator dispersed in said monomers, useful i.a.

Abstract: Unique masked isocyanates well suited for formulation into a variety of coating compositions, for example paint powers, are prepared by condensing an isocyanate with a ring-hydroxylated aromatic compound bearing at least one substituent which comprises a carbonyl or nitrile functional group and the apparent melting point of which being at least 30° C.

Abstract: Provided is a composition useful for obtaining a high gloss coating, for example, a high gloss paint. The composition includes an isocyanate which is at least partially masked by one or more masking agent, and having a degree of liberation with respect to the masking agent at 120 ° C. of 5 % or less. A polyol has a glass transition temperature of about 40° C. or more, a hydroxyl number of about 20 mg KOH/g or more and an average molecular weight Mn of about 500 g/mol or more. Also provided is a process for preparing the composition, wherein the isocyanate, the polyol and any other components are preblended in a blender. The polyol and other meltable components of the blend are melted, homogenized and dispersed in an extruder having one or more screws. Further provided are paint compositions, wherein the paint is a high gloss paint. The compositions are environmentally friendly and result in high gloss coatings having beneficial mechanical properties.

Abstract: Unique masked isocyanates well suited for formulation into a variety of coating compositions, for example paint powders, are prepared by condensing an isocyanate with a ring-hydroxylated aromatic compound bearing at least one substituent which comprises a carbonyl or nitrile functional group and the apparent melting point of which being at least 30° C.

Abstract: The present invention relates to a composition, particularly useful in paint. This composition is defined in that it contains, for successive or simultaneous addition: an isocyanate which is at least partially masked, having a glass transition temperature (sometimes denoted by the abbreviation Tg) of at least 20° C., advantageously of at least 40° C., and a degree of liberation at 120° C. of not more than 5%; a polyol having the following characteristics: a glass transition temperature (sometimes denoted by the abbreviation Tg) which is at least equal to about 40° C., advantageously at least equal to about 50° C.; a hydroxyl number at least equal to about 10 mg/g, advantageously at least equal to about 15 mg/g; an average molecular mass Mn at least equal to about 1000 g/mol and advantageously to 2000 g/mol.

Abstract: The present invention relates to a composition, particularly useful in paint.

Abstract: Unique masked isocyanates well suited for formulation into a variety of coating compositions, for example paint powders, are prepared by condensing an isocyanate with a ring-hydroxylated aromatic compound bearing at least one substituent which comprises a carbonyl or nitrile functional group and the apparent melting point of which being at least 30° C.

Abstract: The present invention relates to a composition, particularly useful in paint. This composition is defined in that it contains, for successive or simultaneous addition: an isocyanate which is at least partially masked, having a glass transition temperature (sometimes denoted by the abbreviation Tg) of at least 20° C., advantageously of at least 40° C., and a degree of liberation at 120° C. of not more than 5%; a polyol having the following characteristics: a glass transition temperature (sometimes denoted by the abbreviation Tg) which is at least equal to about 40° C., advantageously at least equal to about 50° C.; a hydroxyl number at least equal to about 10 mg/g, advantageously at least equal to about 15 mg/g; an average molecular mass Mn at least equal to about 1000 g/mol and advantageously to 2000 g/mol.

Abstract: Organometallic boron/nitrogen polymers, precursors of boron nitride, are prepared by reacting at least one trihalogenoborane with at least one silazane compound containing at least one .tbd.Si--NH--Si.tbd. group, by gradually introducing the silazane compound into the trihalogenoborane, while maintaining the reaction medium at a temperature ranging from -100.degree. to 0.degree. C. and wherein the ratio of the gram equivalents of the .tbd.Si--NH--Si.tbd. groups of the silazane to the number of moles of trihalogenoborane is greater than 1; the resulting organometallic polymers are facilely pyrolyzed into boron nitride ceramic materials.

Abstract: Boron/nitrogen/silicon preceramic polymers are prepared by copolymerizing at least one trihaloborane with at least one disilazane and at least one B-trichloroborazine; the resulting polymers, advantageously in fibrous form, are then facilely crosslinked and pyrolyzed into boron nitride ceramic materials.

Abstract: Organometallic boron/nitrogen polymers, precursors of boron nitride, include recurring structural units of the formulae (I) and (II): ##STR1## wherein X is N-R.sup.3, Y is NR.sup.1 R.sup.2 and Z is N-R, in which R, R.sup.1, R.sup.2 and R.sup.3, which may be identical or different, are each a hydrogen atom, an optionally substituted hydrocarbon radical, or an organosilyl or hydrogenoorganosilyl radical and are prepared by reacting (a) at least one cyclic compound (compound A) containing recurring structural units of the formula (1): ##STR2## wherein A is a halogen atom and R is a hydrogen atom, an optionally substituted hydrocarbon radical, or an organosilyl or hydrogenoorganosilyl radical, with (b) at least one compound including at least one boron atom to which two halogen atoms are directly bonded (compound B), and (c) at least one compound containing at least one NH.sub.2 group compound C); the resulting organometallic polymers are facilely pyrolyzed into boron nitride ceramic materials.

Abstract: Highly pure boron nitride ceramic material, devoid of silicon values and having low carbon content, is prepared by pyrolyzing, under an atmosphere of ammonia, the product of the reaction between (i) at least one B-trihalogeno-borazole having the formula: ##STR1## and (ii) at least one primary amine having the formula:H.sub.2 N--Rin which formulae X is a halogen atom and R is an optionally substituted hydrocarbon radical having from 1 to 6 carbon atoms.

Abstract: Boron/nitrogen preceramic polymers are prepared by reacting (a) the product of mass thermolysis of a compound of Formula (1): ##STR1## in which A is a halogen atom and R is a hydrogen atom, a hydrocarbon radical, or an organosilyl or hydrogenoorganosilyl radical, with (b) an amino compound containing at least one --NH.sub.2 group; the resulting polymers are facilely pyrolyzed into boron nitride ceramic materials.