Optical fiber coating composition

1. A coated optical fiber comprising:

a glass optical fiber comprising a glass core and a glass cladding disposed about the glass core; and

a cured reaction product of a radiation-curable optical fiber coating composition disposed about the glass optical fiber, the radiation-curable optical fiber coating composition comprising

at least 20 wt % of one or more at least trifunctional ethylenically unsaturated monomers, each having three or more free radical polymerizable ethylenic unsaturations;

at least 20 wt % of one or more at least trifunctional thiol monomers, each having three or more free radical polymerizable thiols; and

an effective amount of a free radical photoinitiator,

wherein a ratio of a number of polymerizable ethylenic unsaturations of the radiation-curable optical fiber coating composition to a number of polymerizable thiols of the radiation-curable optical fiber coating composition in a range of 1.90 to 5.00, and

wherein at least 50 wt % of a total amount of the one or more at least trifunctional ethylenically unsaturated monomer is made up of aromatic monomers and/or at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomers is made of up aromatic monomers.

2. The coated optical fiber according to claim 1 , wherein an amount of the one or more at least trifunctional ethylenically unsaturated monomers is at least 35 wt %.

3. The coated optical fiber according to claim 1 , wherein an amount of the one or more at least trifunctional thiol monomers is at least 35 wt %.

4. The coated optical fiber according to claim 1 , wherein a weight average molecular weight of the one or more at least trifunctional ethylenically unsaturated monomers is less than 900 g/mol.

5. The coated optical fiber according to claim 1 , wherein at least 50% of a total amount of the one or more at least trifunctional ethylenically unsaturated monomers is made up of 1,3,5-triallyl-1,3-5-triazine-2,4,6(1H,3H,5H)trione (triallyl isocyanurate); 2,4,6-triallyloxy-1,3,5-triazine (triallyl cyanurate); triallyl trimesate; trimethylolpropane tri(meth)acrylate; ethoxylated trimethylolpropane tri(meth)acrylate; propoxylated trimethylolpropane tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; ethoxylated pentaerythritol tetra(meth)acrylate; propoxylated pentaerythritol tetra(meth)acrylate; pentaerythritol tri(meth)acrylate; ethoxylated pentaerythritol tri(meth)acrylate; propoxylated pentaerythritol tri(meth)acrylate; ethoxylated glyceryl tri(meth)acrylate; propoxylated glyceryl tri(meth)acrylate; tris(2-hydroxyethyl)isocyanurate triacrylate; allylated or (meth)acrylated derivatives of hexamethoxymethylmelamine having the formula C 3 N 3 —(N(CH 2 OR) 2 ) 3 in which each R is H, C 4 alkyl)-, allyl-, or (meth)acryl(C 2 -C 4 alkyl)-, provided that at least 3 Rs are polymerizable; the compound of any of formulae (I)-(VI)

pentaerythritol allyl ether having at least 3 allyl substitutions; and/or trimethylolpropane triallyl ether.

6. The coated optical fiber according to claim 1 wherein at least 50 wt % of a total amount of the one or more at least trifunctional ethylenically unsaturated monomers is made up of aromatic monomers.

7. The coated optical fiber according to claim 1 , wherein a weight average molecular weight of the one or more at least trifunctional thiol monomers is less than 900 g/mol.

8. The coated optical fiber according to claim 1 , wherein at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomers is made up of tris(2-(3-mercaptopropionyloxy)ethyl)isocyanurate; tris(2-(3-mercaptobutyloxy)ethyl)isocyanurate; trimethylolpropane tris(3-mercaptoproprionate); pentaerythritol tetrakis(3-mercaptoproprionate); dipentaerythritol hexa(3-mercaptoproprionate); trimethylolpropane tris(thioglycolate); tris[2-(2-mercaptoacetyloxy)ethyl]isocyanurate; pentaerythritol tetrakis(3-thioglycolate); dipentaerythritol hexa(thioglycolate); 2,3-(dimercaptoethylthio)-1-mercaptopropane; and/or 1,2,3-trimercaptopropane.

9. The coated optical fiber according to claim 1 wherein at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomers is made up of aromatic monomers.

10. The coated optical fiber according to claim 1 , further comprising one or more monofunctional or difunctional ethylenically unsaturated monomers in a total amount of no more than 50 wt % of the radiation-curable optical fiber coating composition.

11. The coated optical fiber according to claim 10 , wherein the one or more monofunctional or difunctional ethylenically unsaturated monomers are selected from the group consisting of trimethylolpropane diallyl ether, trimethylolpropane di(meth)acrylate, allyl- or (meth)acryl terminated polyols, allyl- or (meth)acryl-terminated urethane oligomers, maleimides, bisallyl bisphenol A; ortho,ortho-bisallyl bisphenol A, bisphenol A di(meth)acrylate, alkoxylated bisphenol A di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, isobornyl (meth)acrylate, phenoxyethyl (meth)acrylate, N,N-dimethylacrylamide, N,N-diethylacrylamide, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, 2-ethoxyethoxy-ethyl (meth)acrylate, lauryl vinyl ether, 2-ethylhexyl vinyl ether, N-vinyl formamide, isodecyl (meth)acrylate, isooctyl (meth)acrylate, vinyl-caprolactam, N-vinylpyrrolidone, ethyleneglycolphenylether (meth)acrylate, polyethyleneglycolphenylether (meth)acrylate, polypropyleneglycolphenylether (meth)acrylate, alkyl-substituted phenyl derivatives of the above monomers, polyethyleneglycolnonylphenyl-ether (meth)acrylate, C 2 -C 18 hydrocarbon-diol di(meth)acrylate, C 4 -C 18 hydrocarbon divinyl ethers, 1,6-hexanediol di(meth)acrylate, hexanedioldivinylether, triethylene-glycol di(meth)acrylate, ethoxylated bisphenol-A di(meth)acrylate, and tripropyleneglycol di(meth)acrylate and diallylphthalate.

12. The coated optical fiber according to claim 1 , further comprising one or more monofunctional or difunctional thiol monomers wherein a total amount of any monofunctional or difunctional thiol monomers is no more than 50 wt % of the radiation-curable optical fiber coating composition.

13. The coated optical fiber according to claim 12 , wherein the one or more monofunctional or difunctional thiol monomers are selected from the group consisting of 2,5-dimercaptomethyl-1,4-dithiane, 2,3-dimercapto-1-propanol, 2-mercapto-ethylsulfide, ethylene glycol bis(thioglycolate), ethylene glycol bis(3-mercaptopropionate), 1,6-hexanedithiol, 1,2-benzenedithiol, 1,3-benzenedithiol, and isophorone diurethane thiol.

14. The coated optical fiber according to claim 1 , further comprising one or more copolymerizable oligomers in a total amount of no more than 20 wt % of the radiation-curable optical fiber coating composition.

15. The coated optical fiber according to claim 1 , wherein the radiation-curable optical fiber coating composition is substantially solvent-free.

16. The coated optical fiber according to claim 1 , wherein the radiation-curable optical fiber coating composition includes at least 35 wt % of the one or more at least trifunctional thiol monomers, a weight average molecular weight of the one or more at least trifunctional thiol monomers being less than 900 g/mol; and at least 35 wt % of the one or more at least trifunctional ethylenically-unsaturated monomers, a weight average molecular weight of the one or more at least trifunctional ethylenically unsaturated monomers being less than 900 g/mol.

17. The coated optical fiber according to claim 1 , wherein the radiation-curable optical fiber coating composition exhibits no more than 4% weight loss at 500 hours and no more than 6% weight loss at 1000 hours at 200° C. in air when cured as a film 7 mm in thickness by exposure to a metal halide lamp and then allowed to age for at least one day before heat testing.

18. The coated optical fiber according to claim 1 ,

wherein an amount of the one or more at least trifunctional ethylenically unsaturated monomers is at least 35 wt %;

wherein an amount of the one or more at least trifunctional thiol monomers is at least 35 wt %;

wherein a weight average molecular weight of the one or more at least trifunctional ethylenically unsaturated monomers is less than 900 g/mol;

wherein at least 50 wt % of a total amount of the one or more at least trifunctional ethylenically unsaturated monomer is made up of aromatic monomers;

wherein a weight average molecular weight of the one or more at least trifunctional thiol monomers is less than 900 g/mol;

wherein at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomer is made up of aromatic monomers;

having no more than 30 wt % of monofunctional or difunctional ethylenically unsaturated monomers;

having no more than 20 wt % of copolymerizable oligomers; and

wherein the radiation-curable optical fiber coating composition is substantially solvent-free.

19. A method for making a coated optical fiber according to claim 1 , the method comprising

providing a glass optical fiber comprising a glass core and a glass cladding disposed about the glass core;

disposing the radiation-curable optical fiber coating composition about the glass optical fiber; and

curing the radiation-curable optical fiber coating composition disposed about the glass optical fiber by exposing it to ultraviolet radiation.

20. A coated optical fiber comprising:

a glass optical fiber comprising a glass core and a glass cladding disposed about the glass core; and

a cured reaction product of a radiation-curable optical fiber coating composition disposed about the glass optical fiber, the radiation-curable optical fiber coating composition comprising

at least 20 wt % of one or more at least trifunctional ethylenically unsaturated monomers, each having three or more free radical polymerizable ethylenic unsaturations;

at least 20 wt % of one or more at least trifunctional thiol monomers, each having three or more free radical polymerizable thiols; and

an effective amount of a free radical photoinitiator,

wherein at least 50 wt % of a total amount of the one or more at least trifunctional ethylenically unsaturated monomer is made up of aromatic monomers and/or at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomers is made of up aromatic monomers, and

wherein at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomers is made of up aromatic monomers.

21. A coated optical fiber comprising:

a glass optical fiber comprising a glass core and a glass cladding disposed about the glass core; and

a cured reaction product of a radiation-curable optical fiber coating composition disposed about the glass optical fiber, the radiation-curable optical fiber coating composition comprising

at least 20 wt % of one or more at least trifunctional ethylenically unsaturated monomers, each having three or more free radical polymerizable ethylenic unsaturations;

at least 20 wt % of one or more at least trifunctional thiol monomers, each having three or more free radical polymerizable thiols; and

an effective amount of a free radical photoinitiator,

wherein a ratio of a number of polymerizable ethylenic unsaturations of the radiation-curable optical fiber coating composition to a number of polymerizable thiols of the radiation-curable optical fiber coating composition is at least about 1,

wherein at least 50 wt % of a total amount of the one or more at least trifunctional ethylenically unsaturated monomer is made up of aromatic monomers and/or at least 50 wt % of a total amount of the one or more at least trifunctional thiol monomers is made of up aromatic monomers, and

wherein at least 50% of a total amount of the one or more at least trifunctional ethylenically unsaturated monomers is made up of 1,3,5-triallyl-1,3-5-triazine-2,4,6(1H,3H,5H)trione (triallyl isocyanurate); 2,4,6-triallyloxy-1,3,5-triazine (triallyl cyanurate); triallyl trimesate; trimethylolpropane tri(meth)acrylate; ethoxylated trimethylolpropane tri(meth)acrylate; propoxylated trimethylolpropane tri(meth)acrylate; pentaerythritol tetra(meth)acrylate; ethoxylated pentaerythritol tetra(meth)acrylate; propoxylated pentaerythritol tetra(meth)acrylate; pentaerythritol tri(meth)acrylate; ethoxylated pentaerythritol tri(meth)acrylate; propoxylated pentaerythritol tri(meth)acrylate; ethoxylated glyceryl tri(meth)acrylate; propoxylated glyceryl tri(meth)acrylate; tris(2-hydroxyethyl)isocyanurate triacrylate; allylated or (meth)acrylated derivatives of hexamethoxymethylmelamine having the formula C 3 N 3 —(N(CH 2 OR) 2 ) 3 in which each R is H, (C 1 -C 4 alkyl)-, allyl-, or (meth)acryl(C 2 -C 4 alkyl)-, provided that at least 3 Rs are polymerizable; the compound of any of formulae (I)-(VI)

pentaerythritol allyl ether having at least 3 allyl substitutions; and/or trimethylolpropane triallyl ether.

22. The coated optical fiber according to claim 21 ,

wherein the radiation-curable optical fiber coating composition includes

at least 35 wt % of the one or more at least trifunctional thiol monomers, a weight average molecular weight of the one or more at least trifunctional thiol monomers being less than 900 g/mol, and

at least 35 wt % of the one or more at least trifunctional ethylenically-unsaturated monomers, a weight average molecular weight of the one or more at least trifunctional ethylenically unsaturated monomers being less than 900 g/mol; and

wherein the ratio of the number of polymerizable ethylenic unsaturations of the radiation-curable optical fiber coating composition to the number of polymerizable thiols of the radiation-curable optical fiber coating composition is 1.25-5.00.