| 摘要 |
Radiation-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 DEG C., or a topcoat for overcoating softer buffer coatings which resist microbending down to around -60 DEG C. The coating compositions consist essentially of a polyacrylate-terminated oligomer which contains a plurality of urethane and/or urea groups and which is formed from components including: (1) hydroxyl or amine functional polymer having a molecular weight of from about 300 to about 4000 and a functionality of 3 or 4, or a mixture thereof; (2) hydroxyl or amine functional polymer having a molecular weight of from about 200 to about 4000 and a functionality of two; (3) a monohydric acrylate; and (4) organic diisocyanate in an amount sufficient to react with all of the reactive groups in components (1), (2) and (3). The monohydric acrylate is used in an amount to react with all of the reactive groups on component (1) less from 10% to 80% of the last reactive group thereon, and component (2) is used in an amount corresponding to the deficiency of monohydric acrylate. The polyacrylate-terminated oligomer is used 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, but solvent can be used in electron beam-curing compositions.
|
