A method of extracting (meth)acrylic acid from an aqueous reaction medium into an organic phase in contact therewith is described. The aqueous reaction medium is formed from at least one base catalyst and at least one dicarboxylic acid selected from maleic, fumaric, malic, itaconic, citraconic, mesaconic, and citramalic acid or mixtures thereof in aqueous solution and contains the base catalyzed decarboxylation products of the base catalyzed reaction. The method includes either the addition of at least one of the said dicarboxylic acids and/or a pre-cursor thereof to the aqueous reaction medium to enhance the solvent extraction of the (meth)acrylic acid into the organic solvent or maintaining the level of base catalyst to dicarboxylic acid and/or pre-cursor at a sub-stoichiometric level during the extraction process. The method extends to a process of producing (meth)acrylic acid, its esters and polymers and copolymers thereof.

The present invention describes the preparation of highly-performing Acrylamide Free polyelectrolytic polymers by using not toxic monomers and the way such new monomers can be advantageously used in the field of several civil and/or industrial applications. The new polyelectrolytic polymers developed herein can be then used both as replacement of the common acrylamide-based polymers and in the applications wherein the absence of residual toxic polymerization monomers is requested.

The present invention describes the preparation of highly-performing Acrylamide Free polyelectrolytic polymers by using not toxic monomers and the way such new monomers can be advantageously used in the field of several civil and/or industrial applications. The new polyelectrolytic polymers developed herein can be then used both as replacement of the common acrylamide-based polymers and in the applications wherein the absence of residual toxic polymerization monomers is requested.

In one embodiment, a resist material to be used in an imprint process includes a diluent monomer having a hydroxyl group and at least one functional group selected from a vinyl ether group, an epoxy group and an oxetanyl group. The material further includes a dendrimer having at least two reactive groups for photo-cationic polymerization, The material further includes a photo-acid generator as a polymerization initiator.

A colored composition is provided having higher heat resistance as compared with a conventional colored composition using triarylmethane derivative.

The present invention relates to a compound represented by the following general formula (1), and a polymer having a monomer unit derived from the compound, and the like.

##STR00001##

(wherein R.sub.1 to R.sub.4 each independently represent an alkyl group or the like; R.sub.5 to R.sub.7 each independently represent a hydrogen atom or a methyl group; n pieces of R.sub.8 each independently represent a halogen atom, an alkyl group, an aryl group, a hydroxy group, a nitro group, a sulfo group, an alkoxy group, or the like; and n represents an integer of 0 to 4. A.sub.1 represents an alkylene group, or the like; A.sub.2 represents NH or O. An.sup. represents an anion containing an aryl group having an electron-withdrawing substituent, a sulfonyl group having an electron-withdrawing substituent, or a halogenated alkyl group.)

Superabsorbent material, comprising clay-crosslinked superabsorbent polymers, obtainable by polymerizing in a spray-stream, polymerizable compounds in the presence of a polymerization initiator system, and nano-sized or individual clay particles, which are all introduced into a vessel by a spraying step in the form of a said spray-stream thereof, whereby said clay particles crosslink said polymers during polymerization. The invention also relates to such a process and absorbent articles comprising such superabsorbent material.

Superabsorbent material, comprising clay-crosslinked superabsorbent polymers, obtainable by polymerizing in a spray-stream, polymerizable compounds in the presence of a polymerization initiator system, and nano-sized or individual clay particles, which are all introduced into a vessel by a spraying step in the form of a said spray-stream thereof, whereby said clay particles crosslink said polymers during polymerization. The invention also relates to such a process and absorbent articles comprising such superabsorbent material.

The present invention describes the preparation of highly-performing Acrylamide Free polyelectrolytic polymers by using not toxic monomers and the way such new monomers can be advantageously used in the field of several civil and/or industrial applications.

The new polyelectrolytic polymers developed herein can be then used both as replacement of the common acrylamide-based polymers and in the applications wherein the absence of residual toxic polymerization monomers is requested.

The present invention describes the preparation of highly-performing Acrylamide Free polyelectrolytic polymers by using not toxic monomers and the way such new monomers can be advantageously used in the field of several civil and/or industrial applications.

The new polyelectrolytic polymers developed herein can be then used both as replacement of the common acrylamide-based polymers and in the applications wherein the absence of residual toxic polymerization monomers is requested.

A method for producing a copolymer for semiconductor lithography containing less metal impurities, and a method for purifying a polymerization initiator for production of the copolymer, are provided. The method for purifying a polymerization initiator to be used for production of a polymer includes a filtering step wherein a solution of a polymerization initiator dissolved in an organic solvent is allowed to pass through a filter having a nominal pore size of not more than 1.0 m, to reduce the sodium content of the polymerization initiator solution to not more than 300 ppb with respect to the weight of the polymerization initiator. Further, the method for producing a copolymer for semiconductor lithography includes a polymerization step wherein the polymer for semiconductor lithography is synthesized by a radical polymerization reaction in the presence of a polymerization initiator purified by the above purification method.