| Title of Invention | "OPTICAL FIBER COMPRISING AN INTERNAL GLASS PORTION" |
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| Abstract | Optical fiber comprising an internal glass portion, a first coating layer disposed to surround said glass portion and a second coating layer disposed to surround said first coating layer, wherein said first coating layer is formed from a cured polymeric material obtained by curing a radiation curable composition comprising a radiation curable oligomer comprising a backbone derived from polypropylene glycol and a dimer acid based polyester potyol, said cured polymeric material having: a) a hardening temperature (Th) of from -10°C to -20°C and a modulus measured at said Th lower than 5.0 MPa; or b) a hardening temperature (Th) of from -20°C to -30°C and a modulus measured at said Th lower than 20.0 MPa; or c) a hardening temperature (Th) lower than -30°C and a modulus measured at said Th lower than 70.0 MPa. |
| Full Text | The present invention relates to optical fiber comprising an internal glass portion. Field of the invention The present invention relates to an optical fiber having a reduced attenuation of the transmitted signal. Background art Optical fibers commonly consist of a glass portion (typically with a diameter of about 120-130 um), inside which the transmitted optical signal is confined, The glass portion is typically protected by an outer coating, typically of polymeric material. This protective coating typically comprises a first coating layer positioned directly onto the glass surface, also known as the "primary coating", and of at least a second coating layer, also known as "secondary coating", disposed to surround said first coating. In the art, the combination of primary coating and secondary coating is sometimes also identified as "primary coating system", as both these layer are generally applied during the drawing manufacturing process of the fiber, in contrast with "secondary coating layers" which may be applied subsequently. In this case, the coating in contact with the glass portion of the fiber is called "inner primary coating" while the coating on the outer surface of the fiber is called "outer primary coating". In the present description and claims, the two coating layers will be identified as primary and secondary coating, respectively, and the combination of the two as "coating system". The thickness of the primary coating typically ranges from about 25 µm to about 35 µm, while the thickness of the secondary coating typically ranges from about 10 µm to about 30 µm. These polymer coatings may be obtained from compositions comprising oligomers and monomers that are generally crosslinked by means of UV irradiation in the presence of a suitable photo-initiator. The two coatings described above differ, inter alia, in the mechanical properties of the respective We Claim: 1. Optical fiber comprising an internal glass portion, a first coating layer disposed to surround said glass portion and a second coating layer disposed to surround said first coating layer, wherein said first coating layer is formed from a cured polymeric material obtained by curing a radiation curable composition comprising a radiation curable oligomer comprising a backbone derived from polypropylene glycol and a dimer acid based polyester polyol, said cured polymeric material having: a) a hardening temperature (Th) of from -10°C to -20°C and a modulus measured at said Th lower than 5.0 MPa; or b) a hardening temperature (Th) of from -20°C to -30°C and a modulus measured at said Th lower than 20.0 MPa; or c) a hardening temperature (Th) lower than -30°C and a modulus measured at said Th lower than 70.0 MPa. 2. Optical fiber as claimed in claim 1 wherein said material forming said coating layer has: a) a hardening temperature (Th) of from -10°C to -20°C and a modulus measured at said Th lower than 4.0 MPa; or b) a hardening temperature (Th) of from -20°C to -30°C and a modulus measured at said Th tower than 15.0 MPa; or c) a hardening temperature (Th) lower than -30°C and a modulus measured at said Th lower than 50.0 MPa. 3. Optical fiber as claimed in claim 1 or 2 wherein the equilibrium modulus of said polymeric material is lower than 1.5 MPa. 4. Optical fiber as claimed in claim 1 or 2 wherein the equilibrium modulus of said polymeric material is lower than 1.4 Mpa. 5. Optical fiber as claimed in claim 1 or 2 wherein the equilibrium modulus of said polymeric material is lower than 1.3 Mpa. 6. Optical fiber as claimed in any of the preceding claims wherein the glass transition temperature of the polymeric material is not higher than -30°C. 7. Optical fiber as claimed in any of the preceding claims wherein the glass transition temperature of the polymeric material is not higher than -40°C. 8. Optical fiber as claimed in any of the preceding claims wherein the glass transition temperature of the polymeric material is not higher than -50°C. |
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3210-DELNP-2004-Abstract-(12-09-2008).pdf
3210-DELNP-2004-Assignment-(02-05-2008).pdf
3210-DELNP-2004-Claims-(12-09-2008).pdf
3210-DELNP-2004-Correspondence-Others-(02-05-2008).pdf
3210-DELNP-2004-Correspondence-Others-(12-09-2008).pdf
3210-delnp-2004-correspondence-others.pdf
3210-DELNP-2004-Description (Complete)-(12-09-2008).pdf
3210-delnp-2004-description (complete).pdf
3210-DELNP-2004-Drawings-(12-09-2008).pdf
3210-DELNP-2004-Form-1-(02-05-2008).pdf
3210-DELNP-2004-Form-1-(12-09-2008).pdf
3210-DELNP-2004-Form-2-(12-09-2008).pdf
3210-DELNP-2004-Form-5-(12-09-2008).pdf
3210-delnp-2004-form-6-(02-05-2008).pdf
3210-DELNP-2004-GPA-(12-09-2008).pdf
3210-DELNP-2004-Petition-138-(12-09-2008).pdf
3210-delnp-2004-petition-138.pdf
| Patent Number | 228685 | ||||||||||||||||||||||||||||||
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| Indian Patent Application Number | 3210/DELNP/2004 | ||||||||||||||||||||||||||||||
| PG Journal Number | 08/2009 | ||||||||||||||||||||||||||||||
| Publication Date | 20-Feb-2009 | ||||||||||||||||||||||||||||||
| Grant Date | 06-Feb-2009 | ||||||||||||||||||||||||||||||
| Date of Filing | 18-Oct-2004 | ||||||||||||||||||||||||||||||
| Name of Patentee | PRYSMIAN CAVI E SISTEMI ENERGIA S.r.l. | ||||||||||||||||||||||||||||||
| Applicant Address | VIALE SARCA 222,MILANO,ITALY | ||||||||||||||||||||||||||||||
Inventors:
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| PCT International Classification Number | C03C 25/10 | ||||||||||||||||||||||||||||||
| PCT International Application Number | PCT/EP02/04512 | ||||||||||||||||||||||||||||||
| PCT International Filing date | 2002-04-24 | ||||||||||||||||||||||||||||||
PCT Conventions:
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