Abstract: 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 an ultraviolet curable coating composition comprising, based on total reactive components, from about 60% up to about 85% of a diepoxide polyacrylate combined with at least about 15% of an monacrylate-functional monomer having a glass transition temperature below 0.degree. C. to provide desired coating viscosity. The diepoxide is a diglycidyl ether of a bisphenol having a molecular weight in the range of about 560 to about 2000 and contains at least 1.8 oxirane groups per molecule, substantially all of these oxirane groups being consumed in the polyacrylate.

Abstract: Ultraviolet curing oligomers and liquid coating compositions based thereon are disclosed which cure with ultraviolet light in the presence of a photoinitiator. The coating compositions can provide either a single coating for optical glass fiber which resists microbending difficulties down to around -40.degree. C., or a topcoat for overcoating softer buffer coatings which resist microbending down to around -60.degree. C. The coating compositions consist essentially of the linear polyacrylate-terminated polyurethane polyurea oligomer in admixture with an ultraviolet curable liquid acrylate or polyacrylate to provide the liquidity needed for application and to adjust the hardness or softness of the cured coating for the selected single coat or topcoat utility. The linear polyacrylate-terminated polyurethane polyurea oligomer comprises a linear polyurethane terminated with an essentially monohydric adduct of low molecular weight diprimary amine with from about 1 to about 2.

Abstract: Ultraviolet curing oligomers and liquid coating compositions based thereon are disclosed which cure with ultraviolet light in the presence of a photoinitiator. The coating compositions can provide either a single coating for optical glass fiber which resists microbending difficulties down to around -40.degree. C., or a topcoat for overcoating softer buffer coatings which resist microbending down to around -60.degree. C. The coating compositions consist essentially of the linear polyacrylate-terminated polyurethane polyurea oligomer in admixture with an ultraviolet curable liquid acrylate or polyacrylate to provide the liquidity needed for application and to adjust the hardness or softness of the cured coating for the selected single coat or topcoat utility. The oligomer contains a linear polyurethane core terminated by urea formation with a polyhydroxy-functional amine containing a single isocyanate-reactive amino hydrogen atom.

Abstract: An ultraviolet curing liquid coating composition is disclosed which, when cured with ultraviolet light in the presence of a photoinitiator, provides a buffer coating for optical glass fiber having adequate strength at room or expected elevated temperature and stability at such elevated temperature, a high index of refraction above 1.48, and a low tensile modulus which remains low to resist microbending difficulties down to around -60.degree. C. This coating composition consists essentially of a linear polyacrylate-terminated polyurethane oligomer in admixture with a liquid linear aliphatic diacrylate in which the two acrylate groups are separated by a molecular weight of at least 400 up to about 4000, said liquid linear diacrylate providing said coating composition with a viscosity suitable for coating application.

Abstract: An ultraviolet curing liquid coating composition is provided which, when cured with ultraviolet light in the presence of an appropriate photoinitiator, provides a buffer coating for optical glass fiber having adequate strength at room or expected elevated temperature and stability at such elevated temperature, a high index of refraction above 1.48, and a low tensile modulus which remains low to resist microbending difficulties down to around -60.degree. C. This coating composition consists essentially of a linear acrylate-terminated polyurethane oligomer including urea groups introduced by the presence in the oligomer of the reaction product with isocyanate functionality of about 30% to about 90% by weight of the acrylate-terminated oligomer of a polyoxyalkylene diamine having a molecular weight in the range of from about 1000 to about 8000 in which the alkylene group contains from 2-4 carbon atoms.

Abstract: An ultraviolet curing liquid coating composition is disclosed which, when cured with ultraviolet light in the presence of an appropriate photoinitiator, provides buffer coatings for optical glass fiber having adequate strength at room or expected elevated temperature and stability at such elevated temperature, a high index of refraction above 1.48, and a low tensile modulus which remains low to resist microbending difficulties down to around -60.degree. C. This coating composition consists essentially of a linear polyacrylate-terminated polyurethane or polyurea oligomer having a room temperature tensile modulus of at least 100 psi., and a tensile modulus at -60.degree. C. which is less than 175,000 psi., when capped with 2-hydroxyethyl acrylate and cured with ultraviolet light, in admixture with a liquid acrylate-functional material which does not increase the low temperature hardness and which provides the liquidity needed for coating application.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.