Politecnico Di Milano

Prysmian S.p.a.

Peysmian S.p.a.

Pamela De Martino

Attilio Citterio

Lidia Terruzzi

Massimo Gola

Ehsan Fallahmohammadi

An optical fibre comprising: an optical waveguide comprising a glass core surrounded by a glass cladding; a coating surrounding said optical waveguide comprising a polymer material comprising a cured polyester obtained by: (a) esterification of a reactant (A) selected from carboxylic acids, triglycerides, and mixtures thereof, having a C16-C24 aliphatic chain comprising at least two conjugated double bonds, with a reactant (B) selected from polyols having at least 3 hydroxyl groups, the polyols being thermally stable up to 300&#xb0; C.; (b) curing of the 10 so obtained polyester, in the presence of a transition metal salt, the transition metal being selected from Mn, Fe, Co, Cu, and Ni. Preferably, the step of curing is a thermal curing, preferably up to 300&#xb0; C. The transition metal salt acts as curing accelerator, i.e. it increases the curing rate so as to match the optical fibre drawing speed, the temperature of the glass exiting the drawing step and the drawing tower height commonly used in industrial plants for optical fibre production.

Optical fibre having a crosslinked polyester coating

The present invention concerns an optical fibre comprising: an optical waveguide comprising a glass core surrounded by a glass cladding; a coating surrounding said optical waveguide comprising a cured polymer material comprising a polyester obtained by esterification of: a reactant A selected from an acid, a triglyceride, or a mixture of triglycerides having a C-Caliphatic chain comprising at least two conjugated double bonds; and a polyol made of at least one monomer comprising at least 3 hydroxyl groups, the polyol being thermally stable up to 300&#xb0; C. (reactant B). The present invention concerns also the above said polyester coating, a method for coating an optical fibre with said polyester coating and a method for obtaining predetermined mechanical properties of a coating for an optical fibre. The cured polymer forming the coating can be prepared by curing the polyester of the invention either thermally or by radiation.

Optical fibre coated with a polyester coating

An optical fibre comprising: an optical waveguide comprising a glass core surrounded by a glass cladding; a primary coating surrounding the optical waveguide; a secondary coating, surrounding the primary coating, comprising a cured polymer material obtained by curing a curable coating composition comprising: (a) a polyester obtained by esterification of a reactant A selected from carboxylic acids, triglycerides, and mixtures thereof, having a C-Caliphatic chain comprising at least two double bonds spaced by one carbon atom at most, with a reactant B selected from polyols having at least 3 hydroxyl groups, the polyols being thermally stable up to 300&#xb0; C.; (b) an aromatic glycidyl epoxy resin; (c) an aliphatic polyether hardener containing from 8 to 64 hydroxy groups and/or from 2 to 4 epoxy groups; and (d) a secondary amine compound as curing agent. Preferably, the step of curing is a thermal curing, preferably up to 300&#xb0; C. When cured by heat, the coating material can be applied during the drawing process of the fibre so as to exploit the heat of the just drawn glass fibre as heat source for curing.

Optical fibre having a crosslinked secondary coating

An optical fibre comprising: an optical waveguide comprising a core surrounded by a cladding; a primary coating surrounding the optical waveguide; and a coating, surrounding the primary coating, comprising a polymer material obtained by radiation curing a polymerizable composition, the polymer material having a degree of crystallinity of at most 12. The coating of the optical fiber according to the present invention exhibits enhanced resistance upon exposure to high temperature, preferably a temperature over 250&#xb0; C., while endowed with required features such as protective capability, elasticity, adhesion to underlying layer and simple manufacturing.

Optical fibre with enhanced high temperature resistance

A power cable having a metallic electrical conductor surrounded by one or more semiconductive layer and more or more insulating layer, wherein the cable has at least one metallic element made of aluminum, having a corrosion inhibitor provided in direct contact with the at least one metallic element made of aluminum.

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Milan, Italy

Pamela De Martino