Elf Atochem Italia S.r.l.

Atofina

Elf Atochem S.r.l.

Daniele Becchi

Leo Mario Saija

Ezio Montessoro

Carlo Sempio

Massimo Cesana

Ivan Fuso Nerini

Mario Lugli

Stefano Finocchiaro

The process comprises the following phases: formation of a pre-emulsion of monomers in water; transfer into the polymerisation reactor with stirring, of (1) reaction stock consisting of a water solution of a surfactant, in an amount by weight relative to the weight of final polymer dispersion of 1&#x2013;15%; (2) a portion of the pre-emulsion prepared in the previous phase, in an amount of 1%&#x2013;10% by weight of the initial pre-emulsion; phase C.1: initiation of the polymerisation ; phase C.2: polymerisation of the monomer mixture at 30&#x2013;90&#xb0; C., by gradually adding into the reactor, separately, the initiator solution and the remaining portion of the pre-emulsion with an added salt, which is soluble in water at 25&#xb0; C. to at least 1% by weight, in an amount so as to have a salt concentration in the added pre-emulsion of 0.02&#x2013;0.25% by weight; phase C.3: scrubbing of the residual monomers.

Process for obtaining aqueous polymer dispersions

Aqueous polymer dispersions

Process for reducing the content of residual monomers, expressed as total VOC lower than 600 ppm and deriving from the monomers utilized to obtain the emulsion lower than 100 ppm; having an amount of wet coagula lower or equal to 500 ppm after wet filtering on 125 micron filter of the emulsion at the outlet after the various dropping phases, in polymrizations and copolymerizations in dispersion or emulsion in aqueous phase based on acrylic monomers, characterized in that it comprises as redox couple the utilization of a reducing agent selected from ascorbic acid or an aldehyde having a number of carbon atoms equal to or higher than 4 and containing at least a salifiable hydrogen, organic or inorganic, or its salts and the inorganic salifiable hydrogen being added to a carboxylic group; the aldehyde reducing agent or its salts being soluble in water for at least 5% by weight, preferably 10% by weight; and from an oxidizing agent consisting of an organic hydroperoxide in aqueous solution, excluding those soluble in H,O for more than 10% by weight, or its salts.

Low VOC emulsion

Process for reducing the content of residual monomers, expressed as total VOC lower than 600 ppm and deriving from the monomers utilized to obtain the emulsion lower than 100 ppm; having an amount of wet coagula lower or equal to 500 ppm after wet filtering on 125 micron filter of the emulsion at the outlet after the various dropping phases, in polymrizations and copolymerizations in dispersion or emulsion in aqueous phase based on acrylic monomers, characterized in that it comprises as redox couple the utilization of a reducing agent selected from ascorbic acid or an aldehyde having a number of carbon atoms equal to or higher than 4 and containing at least a salifiable hydrogen, organic or inorganic, or its salts and the inorganic salifiable hydrogen being added to a carboxylic group; the aldehyde reducing agent or its salts being soluble in water for at least 5% by weight, preferably 10% by weight; and from an oxidizing agent consisting of an organic hydroperoxide in aqueous solution, excluding those soluble in H.sub.2 O for more than 10% by weight, or its salts.

Aqueous emulsions based on acrylic polymers and their use for preparing films to be used in processes of preparation of cathode ray tubes, having filming temperature between about 20 and 40.degree. C. which after drying produce films which, submitted to heating in nitrogen atmosphere, have a weight loss, for films having a thickness of 1-2 mm, and for the following cycle of heating:

Emulsions based on acrylic polymers

This invention relates to aqueous emulsions based on acrylic polymers and their use for preparing films to be used in processes of preparation of cathode ray tubes, having filming temperature between about 20.degree. and 40.degree. C. which after drying produce films which, submitted to heating in nitrogen atmosphere, have a weight loss, for films having a thickness of 1-2 mm, and for the following cycle of heating:

This invention relates to aqueous emulsions based on uncured and uncurable acrylic polymers and their use for the forming process of the cathode ray tube comprising as comonomers the following components:

Process for reducing the content of residual monomers, expressed as total VOC lower than 600 ppm and deriving from the monomers utilized to obtain the emulsion lower than 100 ppm; having an amount of wet coagula lower or equal to 500 ppm after wet filtering on 125 micron filter of the emulsion at the outlet after the various dropping phases, in polymerizations and copolymerizations in dispersion or emulsion in aqueous phase based on acrylic monomers, characterized in that it comprises as redox couple the utilization of a reducing agent selected from ascorbic acid or an aldehyde having a number of carbon atoms equal to or higher than 4 and containing at least a salifiable hydrogen, organic or inorganic, or its salts and the inorganic salifiable hydrogen being added to a carboxylic group; the aldehyde reducing agent or its salts being soluble in water for at least 5% by weight, preferably 10% by weight; and from an oxidizing agent consisting of an organic hydroperoxide in aqueous solution, excluding those soluble in H.sub.2 O for more than 10% by weight, or its salts.

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Reggio Emilia, Italy

Daniele Becchi