Asahi Glass Company, Limited

Hitachi, Ltd.

Masami Yamashita

Takao Doi

Noriko Itaya

Tatsuro Asawa

Haruhisa Miyake

Nobuaki Kunii

Motoyuki Suzuki

Masuo Oku

Yoshio Sugaya

Yoshio Miura

Haruhisa Miyaka

A condensed resin dispersion having fine particles of a condensed resin dispersed stably in a polyether polyol (c), the condensed resin being a reaction product of an aldehyde and a compound condensable with the aldehyde, or of their precondensate, wherein the fine particles of the condensed resin are fine condensed resin particles formed by the reaction and precipitation conducted in an isocyanate-modified polyether (b) obtained by reacting an organic polyisocyanate to a polyether (a) having at least one active hydrogen group reactive with an isocyanate group, or to such a polyether (a) and a low molecular weight active hydrogen-containing compound having at least one active hydrogen group, and having substantially no free isocyanate group.

Condensed resin dispersion and process for its production

A process for producing a condensed resin dispersion, which comprises subjecting an aldehyde and a compound condensable with the aldehyde, or their precondensate, to a condensation reaction in a dispersion medium consisting essentially of water and/or an organic solvent, to precipitate fine condensed resin particles which hardly settle in said dispersion medium, and then replacing the water and/or the organic solvent by an active hydrogen-containing compound having at least two active hydrogen-containing groups reactive with isocyanate groups.

Process for producing a condensed resin dispersion

A focus servo system for an optical video disc player. A pair of signals generated by two pairs of photo-cells are supplied to an adder and a differential amplifier, an output signal of the adder is supplied to a first comparator and an output signal of the differential amplifier is supplied to a second comparator. When an output signal of the adder reaches a reference voltage of the first comparator, a focus servo pull-in range is detected. Thereafter, when an output signal of the differential amplifier reaches a reference voltage of the second comparator, a stable operation condition of the focus servo system is detected and a servo system loop is closed so that a malfunction is prevented.

Focus servo system having object lens protection circuit for an optical

A modified polytetrafluoroethylene is produced by polymerizing tetrafluoroethylene in an aqueous medium containing a dispersing agent with a polymerization initiator source and then, copolymerizing tetrafluoroethylene and a fluorinated monomer having an acid type functional group as a copolymerizable modifier in the presence of the resulting polytetrafluoroethylene to obtain a modified polytetrafluoroethylene having the modifier component of 0.001 to 10 mol %.

Process for producing modified polytetrafluoroethylene

A fluorinated copolymer having ion-exchange group is produced by copolymerizing a fluorinated ethylenic unsaturated monomer and a functional monomer having a functional group of carboxylic acid group or a group which can be converted to carboxylic acid group in an aqueous medium in the presence of a polymerization initiator source and in the presence of a specific molecular weight regulator. The specific molecular weight regulator is selected from the group consisting of aliphatic alkanes alicyclic alkanes and water soluble organic solvents and controls the molecular weight without lowering the copolymerization velocity and without lowering the stability of the aqueous latex.

Process for producing fluorinated polymer having ion-exchange groups

A fluorinated copolymer having ion-exchange group is produced by copolymerizing a fluorinated ethylenic unsaturated monomer and a functional monomer having a functional group of carboxylic acid group or a group which can be converted to carboxylic acid group in an aqueous medium in the presence of a polymerization initiator source. The fluorinated copolymer obtained by the copolymerization is treated with an alcohol at higher than 20.degree. C. in the form of particles before a molding. The melt flowability of the fluorinated copolymer is improved.

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Yokohama, Japan

Masami Yamashita