Low density UV-curable optical fiber coating, fiber made therewith, and method of fiber manufacture
Disclosed herein is a composition for coating an optical fiber comprising a free radically curable acrylate and/or a methacrylate functionalized oligomer having a density of less than 1.0 g/cm 3 ; where the acrylate and/or the methacrylate functionalized oligomer has a functionality of 1 or more; a photoinitiator; and optionally a free radically curable acrylate and/or methacrylate diluent monomer that has a density of less than 1.0 g/cm 3 ; where the coating composition is disposed and cured on an optical fiber; where the density of the cured coating is less than 1.0 g/cm 3 ; and where the average functionality of the composition is greater than one.
1. A composition for coating an optical fiber comprising:
a free radically curable acrylate and/or a methacrylate functionalized oligomer having a density of less than 1.0 g/cm 3 ; where the acrylate and/or the methacrylate functionalized oligomer has a functionality of 1 or more;
a photoinitiator; and
optionally a free radically curable acrylate and/or methacrylate diluent monomer that has a density of less than 1.0 g/cm 3 ; where the coating composition is disposed and cured on an optical fiber; where the density of the cured coating is less than 1.0 g/cm 3 ; and where the average functionality of the composition is greater than one; where a cured coating manufactured from the composition has an elastic modulus at 23° C. of 0.3 to 100 megapascals.
2. The composition of claim 1 , where the composition has a refractive index greater than silica and a viscosity of 1000 to 100,000 centipoise when measured at room temperature.
3. The composition of claim 1 , where the free radically curable acrylate and/or a methacrylate functionalized oligomer comprises a urethane (meth)acrylate, an epoxy (meth)acrylate, a polybutadiene (meth)acrylate, a polybutadiene urethane (meth)acrylate, a polybutadiene epoxy (meth)acrylate, a polyisoprene (meth)acrylate, a polyisoprene urethane (meth)acrylate, a polyisoprene epoxy (meth)acrylate, a hydrocarbon (meth)acrylate, a hydrocarbon urethane (meth)acrylate, a hydrocarbon epoxy (meth)acrylate, a hydrophobic (meth)acrylate ester, a hydrophobic urethane (meth)acrylate ester, a hydrophobic epoxy (meth)acrylate ester, a pentadiene (meth)acrylate, a pentadiene urethane (meth)acrylate, a pentadiene epoxy (meth)acrylate, or a combination thereof.
4. The composition of claim 1 , where the free radically curable acrylate and/or a methacrylate functionalized oligomer comprises a backbone that comprises a polybutadiene, a substituted polybutadiene, a polyisoprene, a polypentadiene, a polycyclopentadiene, hydrogenated variants of the foregoing dialkene oligomers, polyisobutylene, or a combination thereof.
5. The composition of claim 1 , where the free radically curable acrylate and/or a methacrylate functionalized oligomer comprises at least one of the structures of formulas (1)-(10)
where in formulas (1)-(10), R has a structure represented by formulas (11)-(13) below
where R 1 and R 2 are independently a C 2-10 alkyl, branched alkyl, cycloaliphatic group, an aromatic group one or more of the carbon atoms are substituted, R 3 is a hydrogen or a methyl group.
6. The composition of claim 5 , where R has the structure
7. The composition of claim 1 , where the acrylate oligomer is a polybutadiene diacrylate oligomer or a polybutadiene urethane acrylate oligomer.
8. The composition of claim 1 , where the acrylate or methacrylate oligomers are present in amounts of 60 to 99 wt %, based on the total weight of the composition prior to curing.
9. The composition of claim 1 , where the acrylate and/or methacrylate diluent monomers are compatible in a liquid phase with the acrylate and/or methacrylate oligomers.
10. The composition of claim 1 , wherein a ratio of methacrylate to acrylate functionalities is less than 0.5.
11. The composition of claim 9 , where the acrylate and methacrylate diluent monomers comprise alkyl acrylate and alkyl methacrylate monomers respectively.
12. The composition of claim 9 , where the alkyl acrylate and alkyl methacrylate diluent monomers comprise alkyl chains that are linear or branched.
13. The composition of claim 12 , where the alkyl chains are selected from the group consisting of octyl, nonyl, decyl, undecyl, dodecyl, isooctyl, isodecyl, tridecyl, and lauryl.
14. The composition of claim 9 , where the acrylate and/or methacrylate diluent monomers are present in amounts of 1 to 40 wt %, based on the total weight of the composition prior to curing.
15. An article comprising the composition of claim 1 .
16. The article of claim 15 where the article is an optical fiber.
17. A method comprising:
disposing onto an optical fiber the composition of claim 1 comprising:
a free radically curable acrylate and/or a methacrylate functionalized oligomer; a photoinitiator; and optionally a free radically curable acrylate and/or methacrylate diluent monomer; where the coating composition is disposed and cured on an optical fiber; and where the average functionality of the composition is greater than one; and
curing the composition using ultraviolet radiation to produce a coating that has a density of less than 1.0 g/cm 3 .
18. The method of claim 17 , where the primary coating has an elongation at break of greater than 15% and an elastic modulus of 0.3 to 100 megapascals.
19. The method of claim 18 , where the primary coating has an elastic modulus of 1 to 10 megapascals.
20. The method of claim 17 , further comprising disposing on the coating another UV curable coating or an extruded thermoplastic buffer.
21. The method of claim 17 , where the coating has a thickness on the optical fiber of less than 135 micrometers.
22. An optical fiber manufactured according to the method of claim 17 .