Coated optical fibers

• US 20040013382A1
• Filed: 04/24/2003
• Published: 01/22/2004
• Est. Priority Date: 04/24/2002
• Status: Active Grant

• Current Assignee: DSM IP Assets BV (DSM-Firmenich AG)
• Original Assignee: DSM IP Assets BV (DSM-Firmenich AG)
• Inventors: Cao, Huimin, Alkema, Duurt, Buijsen, Paul, Johnson, Robert W., Nagelvoort, Sandra, Szum, David M., van Eekelen, Jan
• Granted Patent: US 6,961,508 B2
• Time in Patent Office: Days
• US Class Current: 385/128
• CPC Class Codes: C03C 25/1065 Multiple coatings
• CPC Class Codes: C08G 18/40 High-molecular-weight compounds C08G18/2805 takes precedence
• CPC Class Codes: C08G 18/48 Polyethers
• CPC Class Codes: C08G 18/4854 Polyethers containing oxyalkylene groups having four carbon atoms in the alkylene group
• CPC Class Codes: C08G 18/672 Esters of acrylic or alkyl acrylic acid having only one group containing active hydrogen
• CPC Class Codes: C09D 175/16 having terminal carbon-to-carbon unsaturated bonds
• CPC Class Codes: C09J 175/16 having terminal carbon-to-carbon unsaturated bonds
• CPC Class Codes: G02B 6/02395 Glass optical fibre with a protective coating, e.g. two layer polymer coating deposited directly on a silica cladding surface during fibre manufacture G02B6/02052, G02B6/02057, G02B6/024, G02B6/032, G02B6/105, G02B6/14 take precedence; coating on fibre gratings G02B6/02104; multilayer core or cladding G02B6/036; reinforcing splice joints G02B6/2558; optical cables, i.e. comprising protective structures external to the protective coating such as a jacket or plural coated optical fibres G02B6/44; coating of glass to obtain optical fibres C03C25/104
• CPC Class Codes: Y10S 525/932 Blend of matched optical properties

Abstract

The present invention provides a coated optical fiber having a primary coating and a secondary coating, wherein the primary coating has good microbending resistance and is obtained by curing a composition having high cure speed.

In one embodiment, the present invention provides a coated optical fiber comprising:

(i) an optical fiber;

(ii) a primary coating; and

(iii) a secondary coating;

wherein

(a) said coated optical fiber has an attenuation increase of less than 0.650 dB/km at 1550 nm;

(b) said primary coating has a modulus retention ratio after hydrolytic aging of at least 0.5 and/or a glass transition temperature below −35° C.; and

(c) said primary coating is obtained by curing a primary coating composition having a cure dose to attain 95% of the maximum attainable modulus of less than 0.65 J/cm².

Claims

1. A coated optical fiber comprising:

(i) an optical fiber;

(ii) a primary coating; and

(iii) a secondary coating;

wherein

(a) said coated optical fiber has an attenuation increase of less than 0.650 dB/km at 1550 nm;

(b) said primary coating has a modulus retention ratio after hydrolytic aging of at least 0.5 and/or a glass transition temperature below −

35°

C.; and

(c) said primary coating is obtained by curing a primary coating composition having a cure dose to attain 95% of the maximum attainable modulus of less than 0.65 J/cm².

2. The coated optical fiber of claim 1, wherein said primary coating has an in-situ modulus of less than 0.60 MPa.

3. The coated optical fiber of claim 1, wherein said primary coating has an in-situ modulus of less than 0.56 MPa.

4. The coated optical fiber of claim 1, wherein said attenuation increase is less than 0.5 dB/km.

5. The coated optical fiber of claim 1, wherein said primary coating composition comprises an ethylenically unsaturated oligomer.

6. The coated optical fiber of claim 5, wherein said oligomer is prepared by reacting the following components:

(1) one or more polyisocyanates;

(2) one or more polyols; and

(3) one or more hydroxyfunctional (meth)acrylates.

7. The coated optical fiber of claim 6, wherein said one or more polyols includes polypropylene glycol.

8. The coated optical fiber of claim 6, wherein said one or more polyols consists essentially of polypropylene glycol.

9. The coated optical fiber of claim 6, wherein said one or more polyols includes a polyester polyol.

10. The coated optical fiber of claim 6, wherein said one or more polyols each have a molecular weight of at least 3,000 g/mol.

11. The coated optical fiber of claim 6, wherein said one or more hydroxyfunctional (meth)acrylates includes hydroxyethyl acrylate.

12. The coated optical fiber of claim 1, wherein said primary coating composition comprises one or more monomers.

13. The coated optical fiber of claim 12, wherein said one or more monomers includes an alkoxylated acrylate monomer.

14. The coated optical fiber of claim 12, wherein said one or more monomers includes an alkoxylated aliphatic polyacrylate monomer.

15. The coated optical fiber of claim 1, wherein said cure dose is below 0.55 J/cm².

16. The coated optical fiber of claim 1, wherein said primary coating has a Tg below −

35°

C.

17. The coated optical fiber of claim 1, wherein said primary coating has a Tg below −

45°

C.

18. The coated optical fiber of claim 1, wherein said secondary coating has:

(a) a Tg of at least 40°

C.;

(b) a secant modulus of at least 400 MPa; and

(c) an elongation at break of at least 10%.

19. The coated optical fiber of claim 1, wherein said an optical fiber is an optical glass fiber.

20. An inner primary coating composition having:

(a) an in-situ modulus (after cure) of less than 0.6 MPa;

(b) a cure dose to attain 95% of the maximum attainable modulus of less than 0.65 J/cm²; and

(c) a modulus retention ratio (after cure) of at least 0.6 after hydrolytic aging.

21. The composition of claim 20, wherein said composition comprises a radiation-curable oligomer selected from the group consisting of:

(i) radiation-curable oligomers having a backbone derived from one or more polyether polyols; and

(ii) radiation-curable oligomers having a backbone derived from one or more polyether polyols in combination with one or more polyester polyols;

22. An inner primary coating composition having:

(i) an in-situ modulus (after cure) of less than 0.56 MPa;

(ii) a cure dose to attain 95% of the maximum attainable modulus of less than 0.65 J/cm²; and

(iii) a modulus retention ratio (after cure) of at least 0.5 after hydrolytic aging.