Prysmian S.p.a.

Politecnico Di Milano

Prysmian Cavi E Sistemi Energia S.r.l.

Pirelli & C. S. P. A.

Peysmian S.p.a.

Perelli & C. S.p.a.

Dsm IP Assets B.v.

Lidia Terruzzi

Sabrina Fogliani

Giacomo Stefano Roba

Attilio Citterio

Silvio Frigerio

Pamela De Martino

Luca Castellani

Johannes Adrianus Van Eekelen

Mauro Maritano

Raffaella Donetti

Giovanni Villani

Gouke Dirk Jan Geus

Adrianus Gijsbertus Maria Abel

Massimo Gola

Sandra Joanna Nagelvoort

Luigia Rossiello

Marco Arimondi

Andrea Pelizzoni

Ricardo Antunes De Camargo

Corrado Castoldi

Duurt Pieter Alkema

Gouke Dirk Geus

Adrianus Gijsbertus Abel

Ehsan Fallahmohammadi

Franco Peruzzotti

Giovanni Brandi

Emiliano Resmini

Lisa Grassi

Marco Armondi

Duurt Pieter Willem Alkema

Duurt Pleter Willem Alklma

Duurt Pleter Willem Alkema

Joannes Adrianus Van Eekelen

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.

Power cable having an aluminum corrosion inhibitor

A method of manufacturing an optical fiber preform includes: producing a core rod having a core rod diameter; inserting the core rod into a glass fluorine-doped intermediate cladding tube so as to form a core assembly, the intermediate cladding tube having an inner diameter and an outer diameter, wherein the inner diameter is larger than the core rod diameter, the radial difference between the inner diameter and the core rod diameter defining an annular gap; and applying a negative pressure inside the annular gap; and forming a core preform by heating the core assembly to collapse the intermediate cladding tube around the core rod while maintaining the negative pressure, wherein heating includes moving a heater outside the intermediate cladding tube and along an axial direction of the same, and forming an overcladding region surrounding the core preform so as to form an optical fiber preform.

Method of manufacturing an optical fibre glass preform

A single-mode transmission optical fiber includes a central core region radially outwardly from a centerline to a radius rand having a positive relative refractive index &#x394;; a first inner cladding region extending radially outwardly from the central core to a radius rand having a negative relative refractive index &#x394;; a second inner cladding region extending radially outwardly from the first inner cladding region to a radius rand having a non-negative relative refractive index &#x394;; an intermediate cladding region extending radially outwardly from the second inner cladding region to a radius rhaving a negative relative refractive index &#x394;larger in absolute value than the relative refractive index &#x394;; and an outer cladding region extending radially outwardly from the intermediate cladding region and having a non-negative relative refractive index &#x394;; wherein the relative refractive index &#x394;of the first inner cladding region is &#x2212;0.1&#xb7;10to &#x2212;1.0&#xb7;10and the relative refractive index &#x394;of the intermediate cladding is &#x2212;3.0&#xb7;10to &#x2212;5.0&#xb7;10.

Low macrobending loss single-mode optical fibre

A method of coloring optical fibers during the optical fiber drawing that includes the steps of feeding a natural fiber coating material and a colorant to a mixer; mixing the natural fiber coating material and the colorant in the mixer to obtain a colored coating material; and supplying the colored coating material to a coating die. The feeding step includes exerting on the natural fiber coating a first gas pressure variable with at least one fiber drawing parameter; and exerting on the colorant a second gas pressure variable with at least one fiber drawing parameter.

Method and apparatus for optical fiber coloring

An optical fiber includes a glass core and a protective coating consisting of a single coating layer disposed to surround the glass core, wherein the single coating layer is formed from a cured polymeric material obtained by curing a radiation curable composition including: (i) a radiation curable urethane (meth)acrylate oligomer, preferably including a backbone derived from polyoxytetramethylene glycol, (ii) at least one monofunctional reactive monomer, (iii) at least one multifunctional reactive monomer, and (iv) an adhesion promoter.

Optical fiber with single coating

An optical fiber includes an optical waveguide, a first coating layer disposed to surround the optical waveguide and a second coating layer disposed to surround the first coating layer, wherein the first coating layer is formed by a cured polymeric material obtained by curing a radiation curable composition including at least one (meth)acrylate monomer esterified with at least one branched alcohol having from 9 to 12 carbon atoms, and the second coating layer is formed by a cured polymeric material obtained by curing a radiation curable (meth)acrylate composition including from 0.8% to 1.5% by weight of silica, based on the total weight of the composition.

Optical fiber with double coating

An apparatus for coloring optical fibers, includes: a first reservoir for containing a natural coating material to be applied onto an optical fiber being drawn; a second reservoir for containing a colorant to be mixed with the natural coating material; a mixer in fluid communication with the first and second reservoirs to receive a first flow of natural coating material and a second flow of colorant and to mix the first and second flows to obtain a colored coating material; a coating die in fluid communication with the mixer to receive the flow of colored coating material and to apply it onto the optical fiber being drawn. A first gas pressure source is associated with the first reservoir, exerting on the natural coating material a first gas pressure variable as a function of at least one optical fiber drawing parameter, and a second gas pressure source is associated with the second reservoir, exerting on the colorant a second gas pressure variable as a function of at least one optical fiber drawing parameter. The first and second lines have relevant pressure drop in a ratio corresponding to the ratio of natural coating material and colorant providing the colored coating material.

An optical fiber having: a) a glass portion; and b) at least one protective coating layer disposed to surround the glass portion, the protective coating layer having a modulus of elasticity value between &#x2212;40&#xb0; C. and +60&#xb0; C. between 5 MPa and 600 MPa, preferably not higher than 500 MPa, more preferably not higher than 450 MPa and much more preferably not higher than 300. Preferably the protective coating layer is a single protective coating layer which is disposed in contact with the glass portion.

Optical fiber with cured polymeric coating

An optical fiber having an internal glass portion, a first coating layer surrounding the glass portion and a second coating layer surrounding the first coating layer. The first coating layer is formed from a cured polymeric material obtained by curing a radiation curable composition having a radiation curable oligomer having a backbone derived from polypropylene glycol and a dimer acid based polyester polyol. The cured polymeric material has: (a) a hardening temperature (Th) from &#x2212;10&#xb0; C. to about &#x2212;20&#xb0; C. and a modulus measured at the Th lower than 5.0 MPa; or (b) a hardening temperature (Th) from &#x2212;20&#xb0; C. to about &#x2212;30&#xb0; C. and a modulus measured at the Th lower than 20.0 MPa; or (c) a hardening temperature (Th) lower than about &#x2212;30&#xb0; C. and a modulus measured at the Th lower than 70.0 MPa.

Optical fiber with reduced attenuation loss

Optical fiber capable of controlling attenuation losses caused by microbending on the signal transmitted thereby. The optical fiber comprises: a) an internal glass portion; b) a first coating layer of a first polymeric material surrounding said glass portion; and c) a second coating layer of a second polymeric material surrounding said first coating layer, wherein said first polymeric material has a hardening temperature lower than &#x2212;10&#xb0; C., an equilibrium tensile modulus lower than 1.5 MPa, wherein said first coating layer has a thickness of from 18 &#x3bc;m to 28 &#x3bc;m and wherein said second coating layer has a thickness of from 10 &#x3bc;m to 20 &#x3bc;m.

Optical fiber

Optical fiber having a glass portion; at least one protective coating of thermoplastic material having at least one thermoplastic elastomer; the thermoplastic material having the following characteristics: a modulus of elasticity value at +25&#xb0; C. lower than 150 MPa, preferably at least 10 Mpa, more preferably higher than 20 Mpa, and a Vicat point higher than 85&#xb0; C., preferably higher than 120&#xb0; C., more preferably lower than 350&#xb0; C. Preferably, the coating is a single protective coating directly positioned onto the glass portion.

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Milan, Italy

Lidia Terruzzi