D 1364 BT SECONDARY COATINGS ON OPTICAL FIBRE Russian patent published in 2011 - IPC C09D175/04 C09D175/16 C03C25/10 C03C25/26 

FIELD: chemistry.

SUBSTANCE: radiation curable secondary coating composition contains an Alpha-oligomer which does not contain urethane, obtained via reaction of (a) an acrylate compound selected from alcohol-containing acrylate or alcohol-containing methacrylate compound, (b) an anhydride compound, (c) an epoxide-containing compound, (d) an optional chain extender compound, and (e) an optional catalyst, where said composition additionally contains a Beta-oligomer, where said Beta-oligomer is different from said Alpha-oligomer, where said Beta-oligomer is obtained via reaction of (β1) hydroxyethyl acrylate; (β2) one or more diisocyanates; (β3) polyester polyol or polyether polyol with number-average molecular weight ranging from 300 g/mol to 10000 g/mol; and (β4) a catalyst. The secondary coating composition can additionally contain a Gamma-oligomer which is epoxy diacrylate. The invention also relates to a method coating an optical fibre involving a) using a glass drawing column to obtain optical glass fibre; and b) applying a radiation-curable primary coating composition onto said optical glass fibre; c) optional exposure of said radiation-curable primary coating composition to radiation in order to cure said coating; d) applying a radiation-curable secondary coating composition onto said optical glass fibre; e) and exposing said radiation-curable secondary coating composition to radiation in order to said coating. The invention also relates to a coated wire and a coated optical fibre. The radiation-curable secondary coating on the wire and optical fibre has the following properties after initial curing and after one month of ageing at 85°C and 85% relative humidity: A) % RAU from 80% to 98%; B) in-situ modulus of elasticity between 0.60 GPa and 1.90 GPa; and C) T_c of the tube from 50°C to 80°C.

EFFECT: improved coating properties.

8 cl, 5 tbl