Desoto, Inc.

George I Pasternack

Timothy Edward Bishop

Orvid R Cutler, Jr

John Monroe Zimmerman

Robert E Ansel

Joseph J Stanton

Freshly drawn optical glass fiber is protected by coating it with an ultraviolet-initiated, cationically curable liquid coating composition comprising a cationically curable polyepoxide, a polysiloxane carrying a plurality of hydroxyalkyl groups, and a photoinitiator and/or photosensitizer for an ultraviolet-activated cationic cure. The coatings are of low modulus and retain a low modulus at temperatures as low as -60.degree. C.

Optical glass fiber coated with cationically curable polyepoxide mixtures

Radiation-curable linear addition polymers or copolymers are disclosed having a weight average molecular weight of from about 1,500 to about 15,000 of polymerized monoethylenically unsaturated monomers, which may include up to 25% by weight of an hydroxy-functional monomer, and which carries an hydroxyl group at most of its ends, reacted with a monoethylenically unsaturated monomer carrying a single functional group reactive with the hydroxyl group, so that the polymer carries monoethylenically unsaturated groups bonded to an average of from 1.6 to 5 of the hydroxyl groups per polymer molecule. The preferred radiation-curable polymers are liquid to slowly flowable at room temperature in the absence of organic solvent, and the monoethylenically unsaturated groups are preferably acrylate groups to enable an ultraviolet cure. The terminal hydroxyl groups and the unusually low molecular weight are provided using a bis hydroxyorganic xanthogen disulfide as a chain terminating catalyst when the polymers are formed, and a small proportion of additional hydroxy functionality can be incorporated into the polymers using a hydroxyl functional monomer.

Radiation-curable copolymers of monoethylenic monomers

Buffer-coated and overcoated optical glass fiber is disclosed in which the topcoat has the high strength and high tensile modulus combined with good elongation and solvent resistance associated with extruded jacket coatings, but which is applied by ordinary coating procedures and cured by exposure to ultraviolet radiation. The coating compositions which enable this to be achieved comprise 30% to about 80% of linear diethylenic polyester polyurethanes which are the linear polyurethane reaction product of an organic diisocyanate with hydroxy-functional polyester formed by reacting a diol, such as ethylene glycol, with certain dicarboxylic acids, such as adipic acid. This polyurethane is end capped with a monoethylenically unsaturated monohydric alcohol. At least 50% of this diethylenic polyester polyurethane is combined with at least 5% of liquid diethylenic diester of a diglycidyl ether of a bisphenol, and at least 5% of liquid monoethylenically unsaturated monomer having a glass transition temperature above about 55.degree. C., these proportions being based on total reactive components.

Optical fiber coated with an ultraviolet cured topcoating

Buffer-coated and overcoated optical glass fiber is disclosed in which the topcoat has the high strength and high tensile modulus combined with good elongation and water resistance associated with extruded jacket coatings, but which is applied by ordinary coating procedures and cured by exposure to ultraviolet radiation. The coating compositions which enable this to be achieved comprise 30% to about 80% of linear diacrylate-functional polyurethanes which are the linear polyurethane reaction product of polycarbonate diol with organic diisocyanate in molar proportions providing an average of at least about 2 urethane linkages per molecule, these linear polyurethanes being end-capped with acrylate groups, and these polyurethanes being used in combination with at least 15% of liquid monoethylenically unsaturated monomer having a glass transition temperature above about 55.degree. C.

Ultraviolet curable outer coatings for optical fiber

Radiation-curable coating compositions particularly adapted to reduce the adhesion of the radiation-cured coatings to glass optical fibers (and thereby enhance strippability) are disclosed. These comprise a radiation-curable polyethylenic organic compound and from about 2% to about 20% of the coating composition of an organic polysiloxane carrying a plurality of hydroxy-terminated groups which are joined to some of the silicon atoms in the polysiloxane chain by a carbon-to-silicon bond. The polysiloxane reduces the adhesion of the radiation-cured coating to the glass surface of the fiber. Ultraviolet cures using acrylates as the ethylenic group are preferred.

Strippable radiation-cured coatings for optical fiber and method

Radiation-curable coating compositions adapted for application to buffer-coated optical fibers are disclosed. These are intended to apply an adherent topcoat having greater toughness and greater hardness than the buffer coating. The new compositions comprise: (1) from 25% to 70% of diethylenic-terminated polyurethane, which may include urea linkages, the polyurethane being based on a diisocyanate having an average molecular weight of from 400 to 5000; (2) from 5% to 40% of a diethylenically unsaturated ester of a diglycidyl ether of a bisphenol, said ether having a molecular weight up to about 1000; and (3) from 5% to 30% of liquid radiation-curable monoethylenically unsaturated monomer having a T.sub.g above about 55.degree. C., especially N-vinyl pyrrolidone. Ultraviolet cures using acrylates as the ethylenic group are preferred.

Growing community of inventors

Lincolnshire, IL, United States of America

George I Pasternack