Low volatility radiation curable compositions for coating optical fibers - Patents.com

Abstract

Disclosed and claimed herein is an optical fiber primary coating composition containing an oligomer that is the reaction product of a hydroxy- or thiol-functional backbone compound, an isocyanate compound, and a hydroxyl-functional end capper, optionally a second oligomer, optionally a reactive diluent monomer, a photoinitiator, and optionally one or more additives. The oligomer is present in an amount of 60-98% by weight of the total coating composition and has a molar ratio of isocyanate groups to hydroxyl or thiol groups of 1.0 or less. Also disclosed are methods of coating optical fiber incorporating the compositions described herein, and coated optical fibers and cables produced therefrom.

Description

[Technical field]

[0001] The present invention relates generally to radiation curable formulations that are particularly suitable as optical fiber primary coating compositions, methods for coating optical fibers using the radiation curable formulations as primary coating compositions, and coated optical fibers produced therefrom. [CROSS REFERENCE TO RELATED APPLICATIONS]

[0002] none [Background technology]

[0003] An optical fiber is composed of a glass fiber obtained by hot-melt spinning of glass and one or more coating layers placed on the glass fiber for protection and reinforcement. Optical fibers are produced, for example, by first forming a flexible primary coating layer on the surface of the glass fiber and then forming a more rigid secondary coating layer, called a secondary coating, on the primary coating. Optical fiber ribbons or optical fiber cables are also known that have multiple optical fibers with coating layers bonded together with a bonding material.

[0004] Radiation-curable and thermosetting compositions have long been used to form primary and secondary coating layers because they are particularly fast curing and can impart desirable properties to optical fibers. Typically, radiation-curable optical fiber coatings are the cured product of a composition containing a mixture of one or more components having one or more ethylenically unsaturated (C=C) bonds that undergo crosslinking by free radical polymerization under the influence of irradiation. Such compositions also typically contain a photoinitiator to assist in the radiation curing, especially when the cure is effected by irradiation with ultraviolet (UV) wavelengths.

[0005] The relatively soft inner primary coating provides resistance to undesirable microbending, which would result in further attenuation (i.e., signal loss) of the signal transmission of the coated optical fiber. Microbends are microscopic curvatures in the optical fiber that involve local axial displacements of a few micrometers and spatial wavelengths of a few millimeters. Microbends can be induced by thermal stresses and / or mechanical lateral forces. Coatings can provide lateral force protection to protect the optical fiber from microbending, but the amount of protection provided decreases as the coating thickness decreases.

[0006] The primary coating preferably has a higher refractive index than the cladding of the associated optical fiber so that it can remove erroneous optical signals from the core of the optical fiber. The primary coating should maintain adequate adhesion to the glass fiber during thermal and hydrolytic aging, but can be strippable from the glass fiber for splicing purposes (if desired). Primary coatings typically have a thickness in the range of 20-50 μm (e.g., about 25 or 32.5 μm), with thinner thicknesses in the range of 15-25 μm for 200 μm fibers.

[0007] The harder secondary coating provides resistance to handling forces such as those encountered when the coated optical fiber is ribboned and / or cabled. Radiation-curable optical fiber secondary coating compositions also generally contain a mixture of ethylenically unsaturated compounds, including one or more acrylate-functional oligomers and a photoinitiator dissolved or dispersed in a liquid ethylenically unsaturated diluent. The coating composition is typically applied to the optical fiber in liquid form and then exposed to actinic radiation to effect cure.

[0008] A commonly used method for forming a coating layer on a glass fiber, for example, is to coat the glass fiber with a liquid curable resin composition and cure it with heat or light, especially ultraviolet light. Optical fiber coatings, including primary and secondary layers, are typically applied using one of two processes: wet-on-wet (WOW) and wet-on-dry (WOD). In the WOD process, the fiber first passes through a primary coating application that is cured by exposure to UV radiation. The fiber then passes through a secondary coating application, which is then cured by similar means. In the WOW process, the fiber passes through both the primary and secondary coating applications, after which the fiber proceeds to a curing step. In the wet-on-wet process, the curing lamp between the primary and secondary applications is omitted. Summary of the Invention [Problem to be solved by the invention]

[0009] There is a continuing drive for more sustainable and effective optical fiber coatings. Known optical fiber coatings that cure fast enough, impart sufficient on-fiber performance, and still adhere well to their associated optical fiber substrates still have room for improvement. Specifically, it would be desirable to provide optical fiber primary coatings that maintain acceptable cure speeds and on-fiber performance, as expected by the industry, yet have lower volatility, as evidenced by reduced content of monomers and / or diluent compounds contained therein. [Brief description of the drawings]

[0010] none [Means for solving the problem]

[0011] Several aspects and embodiments of the invention are described herein. A first aspect is an optical fiber primary coating composition comprising, by weight of the total primary coating composition: (a) 60% to 99% by weight of one or more oligomers that are the reaction product of (i) a hydroxy- or thiol-functional backbone compound, (ii) an isocyanate compound, and (iii) a hydroxyl-functional end capper further comprising an ethylenically unsaturated moiety, wherein the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl and thiol groups in (i) is 1.0 or less; (b) optionally, one or more urethane (meth)acrylate oligomers other than (a); (c) optionally, one or more reactive diluent monomers; (d) a photoinitiator; and (e) optionally, one or more additives. When (b) is not present, the one or more oligomers described in (a) preferably have at least two ethylenically unsaturated groups. More preferably, when (b) is absent, the one or more oligomers described in (a) have two ethylenically unsaturated groups.

[0012] In another embodiment according to the first aspect, the one or more oligomers (a) are present in the optical fiber primary coating composition in an amount greater than 60% by weight, such as 65% by weight or more, 70% by weight or more, 75% by weight or more, or 80% by weight or more and less than 96% by weight. In still other embodiments, the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl and thiol groups in (i) is 2 / 3 or more, such as between 2 / 3 (about 0.67) and 1.0. In various other embodiments of the first aspect, the one or more oligomers according to (a) have various urethane linkages, block structures, theoretical molecular weight values, terminal moieties, backbone types, isocyanate types, and hydroxyl functional end cap types. In still other embodiments, more specific types for elements (b)-(e) are described.

[0013] A second aspect of the present invention is a radiation curable formulation characterized in that the formulation comprises: (a) one or more monofunctional telechelic (meth)acrylate oligomers having 0-5 urethane groups and a molecular weight Mn of 750-20000 g / mol; (b) one or more di- or trifunctional telechelic urethane (meth)acrylate oligomers having at least 4 urethane groups and a number average molecular weight (Mn) of 750-100000 g / mol; wherein the molar ratio of (b) to (A) is 0.01-1.5; (c) optionally one or more reactive diluents having Mn<500; (d) optionally a photoinitiator; and (e) optionally one or more additives including adhesion promoters and / or stabilizers.

[0014] According to various other embodiments of the second aspect of the invention, more specific characteristics, compound genus and / or species, and other qualifying information regarding the radiation curable formulation are provided. In still further embodiments of the second aspect, the radiation curable formulation is configured to have specific values ​​for storage modulus and time to reach 30% of storage modulus when cured into a film by the process and dimensions specified elsewhere herein.

[0015] A third aspect of the invention is a method for coating an optical fiber, comprising the steps of providing a glass optical fiber, preferably by drawing the glass optical fiber through a draw tower; applying a primary coating composition onto a surface of the glass optical fiber; optionally applying a dose of UV light sufficient to at least partially cure said primary coating composition; applying a secondary coating composition to said primary coating composition; and exposing said primary coating composition and said secondary coating composition to at least one radiation source capable of emitting ultraviolet radiation to affect curing of said primary coating composition and said secondary coating composition to form a cured primary coating on the surface of the optical fiber and to form a cured secondary coating on the surface of the cured primary coating; wherein the primary coating composition is a composition according to either an embodiment of the first or second aspect of the invention.

[0016] A fourth aspect of the invention is a coated optical fiber comprising a glass core and a cladding layer in contact with and surrounding the glass core; a coating portion, the coating portion further comprising a primary coating layer in contact with and surrounding the cladding layer; and a secondary coating layer in contact with and surrounding the primary coating layer. According to this fourth aspect, the primary coating layer is a cured product of a radiation curable composition according to any of the embodiments of the first or second aspect, and the primary and secondary coatings are applied and cured according to any of the embodiments of the third aspect. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A first aspect of the present invention is a primary coating composition comprising, by weight of the total primary coating composition: (a) between 60% and 99% by weight of one or more oligomers that are the reaction product of (i) a hydroxy- or thiol-functional backbone compound, (ii) an isocyanate compound, and (iii) a hydroxyl-functional end capper further comprising an ethylenically unsaturated moiety, wherein the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl groups and thiol groups in (i) is 1.0 or less; (b) optionally, one or more urethane (meth)acrylate oligomers other than (a); (c) optionally, one or more reactive diluent monomers; (d) a photoinitiator; (e) optionally, one or more additives The optical fiber primary coating composition comprises, consists essentially of, or consists of: When (b) is not present, the one or more oligomers described in (a) preferably have at least two ethylenically unsaturated groups. More preferably, when (b) is not present, the one or more oligomers described in (a) have two ethylenically unsaturated groups.

[0018] However, a second aspect of the present invention also relates to a radiation curable formulation that may be suitable for use as an optical fiber primary coating composition. Specifically, the second aspect of the present invention relates to a radiation curable formulation, the radiation curable formulation comprising: (a) one or more monofunctional telechelic (meth)acrylate oligomers having 0-5 urethane groups and a number average molecular weight (Mn) of 750-20,000 g / mol; (b) one or more di- or trifunctional telechelic urethane (meth)acrylate oligomers having at least four urethane groups and a Mn of 750 to 100,000 g / mol; wherein the molar ratio of (b) to (a) is 0.01 to 1.5; (c) optionally, one or more reactive diluents having a Mn of less than 500 g / mol; (d) optionally, one or more photoinitiators; and (e) optionally, one or more additives including adhesion promoters and / or stabilizers; A radiation curable formulation comprising:

[0019] Thus, a radiation curable composition for coating an optical fiber according to the first and second aspects of the invention may contain an oligomer (a), a second oligomer (b), a reactive diluent component (c), a photoinitiator component (d), and an additive component (e). Such components, described below, may be used in a composition or formulation according to any of the aspects of the invention, including the optical fiber primary coating composition according to the first aspect, the radiation curable formulation according to the second aspect, the primary coating composition used in the method for coating an optical fiber according to the third aspect, and the composition applied and cured onto an optical fiber described in connection with the fourth aspect.

[0020] Surprisingly, it has been found that oligomer (a) tends to have lower viscosity values. Surprisingly, it has been found that the presence of such oligomers in an optical fiber primary coating composition beneficially contributes to the ability to reduce the volatile content of the optical fiber primary coating composition while remaining suitable for use in optical fiber coating applications, and in particular, maintains acceptable viscosity and cure speeds and performance on fiber as expected by the industry. Oligomer Components

[0021] The radiation curable composition according to the invention comprises an oligomeric component; i.e., a collection of one or more individual oligomers having one or more specific structures or types. Oligomer is used herein to mean a molecule of intermediate relative molecular weight, the structure of which actually or conceptually comprises a plurality of units derived from a molecule of lower relative molecular weight. As used herein, a component is considered to be oligomeric if it further has a number average molecular weight (Mn) of greater than about 1 kilodalton (kDa), preferably as measured by size exclusion chromatography (SEC) as described elsewhere herein. It will be understood by those skilled in the art that oligomers having Mn values ​​in this range are generally less volatile than their lower molecular weight analogues and therefore advantageously less likely to migrate from the primary coating composition to the glass tube surrounding the optical fiber during the drawing process.

[0022] In one embodiment, the oligomeric component comprises, consists of, or consists essentially of one or more oligomers having a Mn of at least 1 kilodalton (kDa), or at least 2 kDa, or at least 3 kDa, or at least 5 kDa, or at least 10 kDa, or at least 20 kDa, or at least 30 kDa, or at least 40 kDa, or from 20 to 150 kDa, or from 20 to 130 kDa, or from 20 to 100 kDa, or from 30 to 80 kDa, or from 35 to 55 kDa. According to other embodiments, the oligomeric component comprises, consists of, or consists essentially of one or more oligomers having a theoretical molecular weight (Mn, theo) of at least 1 kDa, or at least 5 kDa, or at least 10 kilodaltons (kDa), more preferably greater than 12 kDa, more preferably greater than 15 kDa, more preferably greater than 17 kDa, and / or less than 150 kDa, more preferably less than 140 kDa, more preferably less than 130 kDa, more preferably less than 120 kDa, or from 1 to 100 kDa, or from 1 to 50 kDa, or from 1 to 25 kDa, or from 15 to 120 kDa, or from 20 to 120 kDa, or from 25 to 120 kDa, or from 25 to 110 kDa, or from 25 to 100 kDa.

[0023] The oligomer component should include one or more reactive oligomers. As used herein, "reactive" means the ability to form a chemical reaction, preferably a polymerization reaction, with another molecule. Thus, a reactive compound is said to have at least one reactive group or functional group. Such reactive group or functional group is preferably a polymerizable group. Although some non-reactive oligomers may be used in certain embodiments of the invention, a large proportion of reactive oligomers is preferred. In one embodiment, the oligomer component consists of or consists essentially of reactive oligomers.

[0024] In other embodiments, the reactive oligomer is telechelic. As used herein, "telechelic" means that such a component (i.e., in this example, an oligomer) contains reactive end groups on all chain ends that can form intra- and intermolecular bonds.

[0025] The reactive oligomer component according to the present invention preferably comprises, consists essentially of, or consists of a reactive oligomer having at least one polymerizable group. In a preferred embodiment, the reactive oligomer component consists of a reactive oligomer having at least one polymerizable group. The polymerizable group may be of any known type. However, in one embodiment, the polymerizable group may comprise, consist essentially of, or consist of an acrylate group or a methacrylate group, or any combination thereof. The reactive oligomer is preferably an ethylenically unsaturated polymerizable compound containing one or more reactive ethylenic double bonds.

[0026] The polymerizable group may be present at any possible point along the length of the reactive oligomer, and may be present as a polymerizable backbone group or a polymerizable end group. A polymerizable backbone group is present along a linear chain or branched from a linear chain along the length of the oligomer, while a polymerizable end group is a polymerizable group present at the end of the oligomer. The polymerizable group may be present alone or directly or indirectly adjacent to other polymerizable groups, such as in a branched or forked pattern at the end of the oligomer (synonymously referred to herein as "end point"). In a preferred embodiment, the polymerizable group comprises, consists essentially of, or consists of a polymerizable end group.

[0027] The reactive oligomer according to the present invention may be of any known type consistent with the definitions specified elsewhere herein. However, according to the first and second aspects, the oligomer component comprises, consists of, or consists essentially of one or more urethane oligomers, preferably reactive urethane oligomers. The urethane oligomer comprises at least one urethane group or moiety, preferably comprising at least a backbone, a polymerizable group, and a urethane group linking the backbone to the polymerizable group. In various embodiments, the reactive oligomer contains 0-5 urethane groups, or 4 or more urethane groups. According to certain embodiments, the urethane oligomer comprises the reaction product of (i) a hydroxy- or thiol-functional backbone compound, such as a polyol; (ii) an isocyanate compound, preferably a polyisocyanate; and (iii) an isocyanate-reactive hydroxyl-functional end capper, preferably also having a (meth)acrylate moiety. In preferred embodiments, the urethane oligomer has a Mn of 1000 g / mol to 10,000 g / mol, or 1200 g / mol to 9,000 g / mol.

[0028] Examples of suitable hydroxy- or thiol-functional backbone compounds include polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, acrylic polyols, and other polyols. These polyols may be used alone or in combination of two or more. In a preferred embodiment, the backbone of the urethane oligomer comprises the reaction product of a polyether polyol. In one embodiment, the backbone comprises the reaction product of a polypropylene glycol (PPG). As used herein, compounds derived from polypropylene glycol include end-capped PPGs, such as EO end-capped PPGs. There is no particular restriction on the manner of polymerization of the structural units in these polyols. Random polymerization, block polymerization, or graft polymerization are each acceptable.

[0029] As used herein, block copolymer refers to a portion of an oligomer or polymer that contains many constitutional units, where at least one constitutional unit contains a feature that is not present in the adjacent portion. As used herein, mono-, di-, and triblock copolymers refer to the average amount of a particular block present in the oligomer. In a preferred embodiment, the particular block refers to a polyether block derived from one or more polyols, preferably polyether polyols, as described elsewhere herein. In one embodiment, the block to which mono-, di-, and / or triblock copolymer refers is a polyether block derived from one or more polyols, as described elsewhere herein. In one embodiment, a monoblock copolymer may be described as a copolymer having an average of only about 1 unit, or about 0.9 to 1.5 or less units, of a particular block, such as a polyether block. In one embodiment, a diblock copolymer may be described as a copolymer having an average of only about 2 units, or at least 1.5 to 2.5 or less units, of a particular block, such as a polyether block. In one embodiment, a triblock copolymer may be described as a copolymer having an average of about 3 units of a particular block, such as a polyether block, or at least 2.5 to less than 3.5 units. The number of polyether units in a given oligomer may be determined by the number of polyether polyol molecules utilized in the synthesis of a single oligomer.

[0030] Examples of polyether polyols include polyethylene glycol, polypropylene glycol, polypropylene glycol-ethylene glycol copolymer, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, and polyether diols obtained by ring-opening copolymerization of two or more ionically polymerizable cyclic compounds. Here, examples of the ionically polymerizable cyclic compounds include cyclic ethers such as ethylene oxide, isobutene oxide, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, isoprene monoxide, vinyl oxetane, vinyl tetrahydrofuran, vinyl cyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, and glycidyl benzoate. Specific examples of combinations of two or more ionically polymerizable cyclic compounds include combinations for producing binary copolymers, such as combinations of tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, and tetrahydrofuran and ethylene oxide; and combinations for producing terpolymers, such as combinations of tetrahydrofuran, 2-methyltetrahydrofuran, and ethylene oxide, combinations of tetrahydrofuran, butene-1-oxide, and ethylene oxide, etc. The ring-opening copolymers of these ionically polymerizable cyclic compounds may be random copolymers or block copolymers.

[0031] These polyether polyols include commercially available products such as PTMG1000, PTMG2000 (manufactured by Mitsubishi Chemical Corp.), PEG#1000 (manufactured by Nippon Oil and Fats Co., Ltd.), PTG650(SN), PTG1000(SN), PTG2000(SN), PTG3000, PTGL1000, and PTGL2000 (manufactured by Hodogaya Chemical Co., Ltd.), PEG400, PEG600, PEG1000, PEG1500, PEG2000, PEG4000, and PEG6000 (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.). Co., Ltd.), P710R, P1010, P2010, and 1044 Pluracol® P series (BASF), Acclaim® series and Acrol® including PPG725, PPG1000, PPG2000, PPG3000, PPG4000, and PPG8000, and MultranolAcclaim® series (Covestro) including PO / EO polyether diols with molecular weights of 2800 or 4000. Additionally, AGC Chemicals offers diols under the trade name Preminol®, such as Preminol S 4013F (Mw 12,000), Preminol 4318F (Mw 18,000), and Preminol 5001F (Mw 4,000).

[0032] The polyester polyol may be a polyester diol obtained by reacting a polyhydric alcohol with a polybasic acid. The polyhydric alcohol may be ethylene glycol, polyethylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, 2-methyl-1,8-octanediol, etc. The polybasic acid may be phthalic acid, dimer acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, etc.

[0033] These polyester polyol compounds are commercially available under trade names such as MPD / IPA500, MPD / IPA1000, MPD / IPA2000, MPD / TPA500, MPD / TPA1000, MPD / TPA2000, Kurapol (registered trademark) A-1010, A-2010, PNA-2000, PNOA-1010, and PNOA-2010 (manufactured by Kuraray Co., Ltd.).

[0034] Triols such as polyester triols or polyether triols are also known. Particularly preferred for use herein are those of the general formula: A(----OH) 3 where A is a chemical organic structure such as an aliphatic, cycloaliphatic, aromatic, or heterocyclic structure, "----" is an oligomer chain such as a polyether chain, a polyester chain, a polyhydrocarbon chain, or a polysiloxane chain, to name a few, and "OH" is a terminal hydroxy group. In one embodiment, the triol comprises, consists of, or consists essentially of a polyether triol, a PO homopolymer, a PE homopolymer, a PO-EO block copolymer, a random copolymer, or a hybrid block-random copolymer. In practice, the polyether triol can be based on glycerol or trimethylolpropane, a PO, EO, or a PO and EO copolymer with EO on the terminal or internal blocks and a MW of 500 to 15,000 Daltons. Another type of polyether triol is a copolymer based on glycerol or trimethylolpropane, such as THF-PO, THF-EO, THF-PO-EO or THF-EO-PO, with a molecular weight of about 500 to 15,000 g / mol. In one embodiment, the triol is derived from bio-based or natural reactants such as certain vegetable oils and fats.

[0035] Commercial examples of suitable triols include related propylene oxide-based polyether triols available from Carpenter under the Carpol® GP designation, such as GP-1000, GP-1500, GP-1500-60, GP-3000, GP-4000, GP-5017, GP-5017-60, GP-5171, GP-6015, GP-6015-60, GP-6037-60, and GP-700. Further triols are available from Covestro under the brand Arcol®, such as Arcol LHT-240 (molecular weight "Mw" declared by the manufacturer is about 700 g / mol), Arcol LHT-112 (Mw 1500 g / mol), Arcol LHT LG-56 (Mw 3000 g / mol) and Arcol LHT-42 (Mw 4200 g / mol), under the trade name Multranol®, such as Multranol 9199 (Mw 4525 g / mol), Multranol 3900 (Mw 4800 g / mol), Multranol 3901 (Mw 6000 g / mol) and Multranol 9139 (Mw 6000 g / mol), and under the trade name Acclaim®, such as Acclaim 703 (Mw 700 g / mol), Acclaim 803 (Mw 800 g / mol), Acclaim 903 (Mw 900 g / mol), Acclaim 1003 (Mw 1000 g / mol), Acclaim 1103 (Mw 1000 g / mol), Acclaim 1203 (Mw 1000 g / mol), Acclaim 1303 (Mw 1000 g / mol), Acclaim 1403 (Mw 1000 g / mol), Acclaim 1503 (Mw 1000 g / mol), Acclaim 1603 (Mw 1000 g / mol), Acclaim 1703 (Mw 1000 g / mol), Acclaim 1803 (Mw 1000 g / mol), Acclaim 1903 (Mw 1000 g / mol), Acclaim 2003 (Mw 1000 g / mol), Acclaim 2003 (Mw 1000 g / mol), Acclaim 2003 (Mw 10 Acclaim 3300N (Mw 3000 g / mol), Acclaim 6300 (Mw 6000 g / mol), and Acclaim 6320 (Mw 6000 g / mol) are commercially available. Additionally, AGC Chemicals offers triols under the trade name Preminol®, such as Preminol S 3011 (Mw 10,000 g / mol), Preminol 7001K (Mw 7,000 g / mol), and Preminol 7012 (Mw 10,000 g / mol).

[0036] While there is no inherent limit to the number of RH groups present in the hydroxyl or thiol functional backbone compound (OH and SH, respectively), preferably the hydroxyl or thiol functional backbone compound has 4 or fewer RH groups. In preferred embodiments, (i) comprises a hydroxyl functional backbone compound having at least 2 hydroxyl groups, or at least 3 hydroxyl groups, or 4 hydroxyl groups.

[0037] The theoretical molecular weight derived from the hydroxyl value of these polyols is usually about 50 g / mol to about 15,000 g / mol, preferably about 500 to 12,000 g / mol, or about 1,000 to about 8,000 g / mol.

[0038] In addition to hydroxy-functional compounds such as polyols, thiol-functional compounds can also be used as (i). Suitable thiol-functional compounds can be prepared from suitable hydroxyl-functional compounds by well-known methods.

[0039] In a preferred embodiment, (i) comprises, consists of, or consists essentially of a hydroxyl-functional backbone compound. In one embodiment, the hydroxyl-functional backbone compound comprises a polyether, polyester, polybutadiene, polycarbonate, or silicone moiety.

[0040] The reactive urethane oligomer also preferably comprises (ii) the reaction product of a (poly)isocyanate compound. The reaction product of a (poly)isocyanate compound, preferably a diisocyanate compound, can be utilized to generate urethane groups or moieties in the reactive urethane oligomer according to the first or second aspect of the present invention. As used herein, an isocyanate compound is defined as any organic compound having at least one isocyanate group per molecule. Examples of suitable isocyanates include diisocyanates, such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, (hydrogenated) xylylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, 3,3'-dimethyl-4,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'-biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylenebis(4-cyclohexylisocyanate), cyanate), 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, 2,4- and / or 4,4'-methylenedicyclohexyl diisocyanate, methylenediphenyl diisocyanate, tetramethylxylylene diisocyanate, 1,5-pentane diisocyanate, bis(2-isocyanato-ethyl) fumarate, 6-isopropyl-1,3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, and lysine isocyanate.

[0041] These diisocyanate compounds may be used alone or in combination of two or more. Preferred diisocyanates are isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, hexamethylene diisocyanate, 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate.

[0042] As used herein, "polyisocyanate" refers to an isocyanate compound having two or more isocyanate moieties per molecule. In one embodiment, the oligomeric component comprises, consists essentially of, or consists of a urethane oligomer that is the reaction product of one or more polyisocyanates. In addition to the diisocyanates mentioned above, polyisocyanates having three isocyanate groups per molecule, i.e., triisocyanates, can also be used. Known triisocyanates include biurets made from hexamethylene diisocyanate (HDI) or HDI trimer, which are commercially available from Covestro under the trade name Desmodur®, including, but not limited to, Desmodur N 3200, Desmodur N 3300, Desmodur N 3390, Desmodur N 3600, Desmodur N 3800, Desmodur N 3900, Desmodur N XP 2580, Desmodur XP 2599, Desmodur XP 2675, Desmodur XP 2731, Desmodur XP 2714, and Desmodur XP 2803.

[0043] Additional commercially available triisocyanates include the Vestanat® T (IPDI-trimer) and HT (HDI-trimer) series of polyisocyanate crosslinkers for 2k systems, available from Evonik.

[0044] The reactive urethane oligomer also preferably includes the reaction product of (iii) a hydroxyl-functional end capper. The compound according to (iii) is preferably reactive with the isocyanate compound from (ii). Preferably, the urethane oligomer also includes the reaction product of an isocyanate-reactive compound having an ethylenically unsaturated moiety as (iii). Preferably, the ethylenically unsaturated moiety is a (meth)acrylate moiety. Any suitable (meth)acrylate, including monomers and oligomers, can be used, but (meth)acrylate monomers are preferred. Such isocyanate-reactive (meth)acrylates preferably include hydroxyl-group-containing (meth)acrylate compounds, which are known to be reactive with isocyanates, including polyisocyanates of (ii). Examples of hydroxyl group-containing (meth)acrylates include (meth)acrylates derived from (meth)acrylic acid and epoxies, as well as (meth)acrylates containing alkylene oxides, more specifically, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and hydroxyethyl caprolactone acrylate, ethoxylated trimethylolpropane diacrylate, glycerol di(meth)acrylate, and glycerol acrylate methacrylate (i.e., 3-(acryloyloxy)-2-hydroxypropyl methacrylate). In a preferred embodiment, (iii) comprises, consists essentially of, or consists of hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, caprolactone (meth)acrylate, glycerol acrylate methacrylate, glycerol di(meth)acrylate, or combinations thereof.

[0045] The hydroxyl functional endcapper (iii) preferably further comprises one or two ethylenically unsaturated moieties, more preferably (iii) the hydroxyl functional endcapper further comprises one ethylenically unsaturated moiety. The compounds described in (iii) may have more than one hydroxyl group per molecule.

[0046] One or more urethanization catalysts are also preferably used in the reaction of the components used to produce the urethane oligomer. Such catalysts include, by way of example, copper naphthenate, cobalt naphthenate, zinc naphthenate, bismuth, di-n-butyltin dilaurate, triethyleneamine, and triethylenediamine-2-methyltriethyleneamine. The catalyst can be used in any suitable amount, or, for example, from about 0.01 to about 1% by weight of the total amount of reactants. The reaction can be carried out at any suitable temperature, such as a temperature of about 10 to about 90°C, preferably about 30 to about 80°C.

[0047] In one embodiment, the composition or formulation comprises at least one oligomer further comprising the reaction product of: (i) a single PPG diol; (ii) a single diisocyanate compound; and (iii) a hydroxyl-functional (meth)acrylate compound.

[0048] The oligomer (a) reactants (i), (ii), and (iii) are selected and configured in a predetermined ratio. The composition includes at least one oligomer (a) in which the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl and thiol groups in (i) is 1.0 or less. The one or more oligomers (a) are the reaction product of (iii) a hydroxyl-functional end capper further comprising an ethylenically unsaturated moiety, (ii) an isocyanate compound, and (i) a hydroxy- or thiol-functional backbone compound, where the molar amount of isocyanate groups in (ii) is equal to or less than the molar amount of hydroxyl and thiol groups in (i). Thus, the one or more oligomers (a) are hydroxy- or thiol-functional, since the oligomer described in (a) is the reaction product of all three components (iii), (ii), and (i). In one embodiment, the composition comprises at least one oligomer (a) in which the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl and thiol groups in (i) is 2:3 or more and 1:0 or less. Thus, in certain embodiments, the composition preferably has at least one oligomer (a) having the aforementioned molar ratio of about 0.67 to 1.0. Surprisingly, the inventors have discovered that oligomers so constructed (otherwise in accordance with the requirements and preferences set forth herein) tend to have lower viscosity values. This is useful because the use of such oligomers tends to minimize the need for large amounts of volatile diluents, which can be included in the overall composition in large amounts.

[0049] Thus, in one embodiment, the composition or formulation comprises at least one oligomer having a viscosity of less than 15 Pa·s, or less than 12, or less than 10 Pa·s, or between 1 and 15 Pa·s, or between 2 and 12 Pa·s, or between 3 and 10 Pa·s, where the viscosity is less than 25° C. and 2500 s. -1 The shear rate is measured.

[0050] The various oligomers of the first and / or second aspects can be configured to have a wide range of functionality. In one embodiment, at least one monofunctional oligomer is utilized. As used herein, "monofunctional" means having between 0.5 and 1.4 polymerizable groups per molecule, as determined, for example, by nuclear magnetic resonance spectroscopy (NMR) methods.

[0051] In one embodiment, difunctional and / or trifunctional oligomers may additionally or alternatively be used. As used herein, "difunctional" means having between 1.95 and 2.05 polymerizable groups per molecule, as determined, for example, by NMR methods. Similarly, "trifunctional" is used herein means an average of 2.95 to 3.05 polymerizable groups per molecule. In a preferred embodiment, the oligomeric component comprises, consists essentially of, or consists of one or more reactive urethane oligomers having an average (meth)acrylate functionality of 1.5 to 4.2, or 1.8 to 3.8, or 1.8 to 3.2, or 1.8 to 2.8. In one embodiment, the average (meth)acrylate functionality of the oligomeric component is 1.5 to 4.2, or 1.8 to 3.8, or 1.8 to 3.2, or 1.8 to 2.8.

[0052] In a preferred embodiment, the composition or formulation contains at least one oligomer that is difunctional or higher to promote suitable crosslinking for use as an optical fiber primary coating. In a further embodiment, the composition or formulation contains a mixture of different oligomers with different functionality, such as at least one monofunctional oligomer and at least one difunctional oligomer, or at least one monofunctional oligomer and at least one trifunctional oligomer, or at least one monofunctional oligomer, at least one difunctional oligomer, and at least one trifunctional oligomer. Of course, other combinations to which the present invention applies may be envisioned by those skilled in the art.

[0053] According to many embodiments of the first and second aspects, the composition or formulation contains more than one oligomer. In an embodiment of the first aspect, the optical fiber primary coating composition comprises (a) one or more oligomers that are reaction products of (i) a hydroxy- or thiol-functional backbone compound, (ii) an isocyanate compound, and (iii) a hydroxy-functional end capper further comprising an ethylenically unsaturated moiety, whereby the molar ratio of (ii) to (i) is equal to or less than 1.0 as described above, and optionally (b), one or more urethane (meth)acrylate oligomers other than those mentioned in (a). In an embodiment of the first aspect, the one or more oligomers according to (a) are present in a major amount relative to the relevant total composition, such as 60% to 99% by weight, or 70% to 99% by weight, or 80% to 96% by weight. If the optical fiber primary coating composition does not include oligomer (b) and one or more oligomers (a) present in the optical fiber primary coating composition are monofunctional with respect to the polymerizable group, one skilled in the art will understand that one or more reactive diluent monomers (c) must be present and at least a portion of (c) must be at least difunctional with respect to the polymerizable group to enable the optical fiber primary coating composition to form a network. If the optical fiber primary coating composition does not include oligomer (b) and does not include reactive diluent monomer (c) or one or more reactive diluent monomers (c) are monofunctional with respect to the polymerizable group, one skilled in the art will understand that at least a portion of the one or more oligomers (a) must be at least difunctional to enable the optical fiber primary coating composition to form a network.

[0054] Since the oligomer (a) is incorporated in such a large amount throughout the composition, it is preferably configured to have a sufficiently low viscosity to allow sufficient processing in optical fiber coating applications. As mentioned above, the aforementioned molar ratio of (ii) to (i) may beneficially contribute to this property of the oligomer (a). Alternatively or additionally, the total number of urethane bonds present in the oligomer (a) may also beneficially contribute thereto. Thus, in one embodiment, the oligomer according to (a) has 1.8 to 2.2 urethane bonds per molecule. Third, the inventors have surprisingly discovered that an oligomer having a sufficiently low viscosity can be obtained by configuring the oligomer to be terminated at one end with a hydroxyl or thiol group.

[0055] In another embodiment of the first aspect, the one or more oligomers (b) are preferably present in an amount of 29.95% by weight or less relative to the total relevant composition. The one or more oligomers (b) may also comprise a reaction product of (i) a hydroxy-functional backbone compound, (ii) an isocyanate compound, and (iii) a hydroxyl-functional end capper. However, in contrast to the oligomer (a), according to certain embodiments, the one or more oligomers (b) are urethane (meth)acrylate oligomers (b) in which the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl groups in (i) is greater than 1.0, or from about 1.5 to about 2.0.

[0056] According to an embodiment of the second aspect, the radiation curable formulation also comprises at least two different oligomers (a) and (b), which are present in a molar ratio of (b) to (a) of 0.01 to 1.5, or 0.02 to 1.5, or 0.04 to 1.5, or 0.06 to 1.5, or 0.02 to 1.2, or 0.06 to 1.2, or 0.02 to 1.2, or 0.04 to 1, or 0.06 to 1, or 0.02 to 0.8, or 0.06 to 0.8, or 0.02 to 0.6, or 0.04 to 0.6, or 0.06 to 0.6. The one or more oligomers (a) according to the second embodiment are monofunctional telechelic (meth)acrylate oligomers having 0 to 3 urethane groups, preferably 1 to 3 urethane groups, and a Mn value of 750 to 20,000 g / mol, or at least 1000 g / mol, or at least 1250 g / mol, or at least 1500 g / mol, and / or up to 18,000 g / mol, or up to 16,000 g / mol, or up to 15,000 g / mol.

[0057] Alternatively, the one or more oligomers (b) according to the second aspect are di- or trifunctional telechelic urethane (meth)acrylate oligomers having at least four urethane groups and a Mn of 750 to 100,000 g / mol, or at least 1000 g / mol, or at least 1250 g / mol, or at least 1500 g / mol, or less than 60,000 g / mol, or less than 40,000 g / mol, or less than 30,000 g / mol, or between 1000 and 20,000 g / mol, or between 1500 and 15,000 g / mol. In a preferred embodiment, the one or more oligomers (b) are polyether oligomers.

[0058] Whether included in the first or second aspect, it is preferred that the total oligomer content (whether (a) alone or also including (b), if present) is very high, relative to the weight of the total composition to which such oligomer or oligomers relate. In one embodiment, the oligomer is present in an amount of at least 60%, or at least 65%, or at least 70%, or at least 80%, or at least 90%, or at least 95%, or at least 98% by weight, relative to the weight of the total composition. Reactive Diluent Component (c)

[0059] The compositions according to the first and / or second aspects of the invention also include a diluent component (c); i.e., a collection of one or more individual diluents having one or more particular structures or types. As used herein, "diluent" means a substance that reduces the viscosity of a larger composition to which it is added or with which it is associated. Various diluents are used to maximize the flowability, and therefore the processability, of the optical fiber coating composition with which they are associated.

[0060] To maximize the curability of the composition associated therewith, the diluent component preferably comprises, consists of, or consists essentially of a reactive diluent. As specified with respect to the qualification of the oligomeric building blocks described elsewhere herein, "reactive" means the ability to form a chemical reaction, preferably a polymerization reaction, with another molecule. Thus, a reactive compound is said to have at least one reactive or functional group. Such reactive or functional group is preferably a polymerizable group.

[0061] It is further preferred that the diluent component comprises, consists of, or consists essentially of reactive diluent monomers. Monomers are molecules of low relative molecular weight, the structure of which can undergo polymerization, thereby being building blocks that contribute to the essential structure of a macromolecule. As used herein, a component is considered a monomer if it further has a number average molecular weight (Mn) of less than about 1000 g / mol. In one embodiment, the reactive diluent component consists of one or more reactive diluent monomers having an Mn of about 86 g / mol (molar mass of methyl acrylate) to 750 g / mol, or 100 g / mol to 350 g / mol, as measured by NMR methods. In an embodiment according to the second aspect, the reactive diluent has an Mn of less than 500 g / mol.

[0062] The diluent component according to the invention comprises, consists essentially of or consists of a reactive diluent monomer having at least one polymerizable group. In a preferred embodiment, the reactive diluent monomer component consists of a reactive diluent monomer having on average one polymerizable group. The polymerizable group of the reactive diluent monomer is preferably capable of (co)polymerizing with the polymerizable group present in the associated reactive oligomer component.

[0063] The polymerizable group of the reactive diluent may be of any known type. However, in one embodiment, the polymerizable group may comprise, consist essentially of, or consist of an acrylate group, an acrylamide group, or an N-vinylamide group, or any combination thereof. The reactive diluent is preferably an ethylenically unsaturated polymerizable compound that contains at least one reactive olefin double bond.

[0064] The polymerizable group may be present at any possible location along the length of the reactive diluent, however, in preferred embodiments the polymerizable group comprises, consists essentially of, or consists of a polymerizable end group.

[0065] The diluent component according to the present invention may comprise any known type of compound or substance consistent with the definitions specified elsewhere herein, however, in preferred embodiments, the diluent component comprises, consists essentially of, or consists of one or more reactive diluent monomers containing a double bond.

[0066] Typical examples of such reactive diluent monomers containing one double bond are alkyl or hydroxyalkyl acrylates such as methyl, ethyl, butyl, 2-phenoxyethyl, 2-ethylhexyl, and 2-hydroxyethyl acrylate, isobornyl acrylate, methyl and ethyl acrylate, lauryl acrylate, ethoxylated nonyl-phenol acrylate, and diethylene-glycol-ethyl-hexyl acylate (DEGEHA). Further examples of these monomers are acrylonitrile, acrylamide, N-substituted acrylamide, vinyl esters such as vinyl acetate, styrene, alkylstyrenes, halostyrenes, N-vinylpyrrolidone, N-vinylamides such as N-vinylcaprolactam, vinyl chloride, and vinylidene chloride. Examples of monomers containing two or more double bonds are ethylene glycol diacrylate, propylene glycol diacrylate, tripropylene glycol diacrylate, neopentyl glycol diacrylate, hexamethylene glycol diacrylate, bisphenol A diacrylate, 4,4'-bis(2-acryloyloxyethoxy)diphenylpropane, trimethylolpropane triacrylate, pentaerythritol triacrylate and tetraacrylate, and vinyl acrylate.

[0067] In a preferred embodiment, component (c), if used, comprises 2-ethylhexyl acrylate, 2-phenoxyethyl acrylate, 2-(2-ethoxyethoxy)ethyl acrylate, n-vinylpyrrolidone, dimethylacrylamide, n-vinylcaprolactam, ethoxylated 2-phenoxyethyl acrylate, 4-hydroxybutyl acrylate, lauryl acrylate, isobornyl acrylate, caprolactone acrylate, ethoxylated nonylphenol acrylate, tridecyl acrylate, or isodecyl acrylate, or a combination thereof.

[0068] In a preferred embodiment, the diluent component comprises, consists essentially of, or consists of one or more monofunctional diluent monomers. In a preferred embodiment, the diluent component comprises, consists essentially of, or consists of functional monomers such as (meth)acrylic monomers.

[0069] One or more of the aforementioned diluents may be used in the compositions according to the invention in any suitable amount to adjust the viscosity of the relevant formulation suitable for the optical fiber coating process being used, according to methods well known in the art to which the invention applies, and may be selected alone or in combination of one or more of the types listed herein. In one embodiment, the diluent component is present in an amount from 20% to 85% by weight, or from 30 to 85% by weight, or from 30 to 80% by weight, or from 30 to 75% by weight, or from 30 to 70% by weight, or from 30 to 65% by weight, or from 30 to 60% by weight, or from 30 to 50% by weight, or from 35 to 85% by weight, or from 35 to 75% by weight, or from 35 to 65% by weight, or from 35 to 55% by weight, or from 40 to 85% by weight, or from 40 to 75% by weight, or from 40 to 65% by weight, or from 40 to 55% by weight, or from 50 to 85% by weight, or from 50 to 75% by weight, or from 50 to 65% by weight, based on the total weight of the radiation curable composition.

[0070] However, in various preferred embodiments, it is desirable to minimize the amount of low molecular weight components present in the composition or formulation. This is because such components are inherently more volatile than their higher molecular weight oligomeric analogues and have a greater tendency to evaporate or separate from the liquid composition during application. Such problems are particularly acute in situations where the composition is exposed to and maintained at higher temperatures, such as those experienced during high speed application and processing onto optical fibers. Evaporation of volatile materials during the optical fiber curing process is highly undesirable, as such volatile components subsequently condense or aggregate on the inner surface of the tube where the fiber coating process takes place. As more components are deposited on the tube surface, they inevitably inhibit the ability of the radiation source to efficiently cure the optical fiber coating composition, since they prevent a portion of the light from reaching the tube surface. In addition to this, such volatile materials can harden the inner surface of the tube, necessitating more frequent and inconvenient process stop cleaning operations. The inventors have surprisingly discovered that by formulating compositions or formulations of the type defined herein, such as by including the above-mentioned oligomers (a) and (b), it is possible to reduce the amount of reactive diluent present in the composition and still maintain sufficient cure speed, processability, and performance on the fiber.

[0071] Thus, in preferred embodiments, component (c) is present in an amount of less than 40% by weight, or less than 30% by weight, or no more than 29.95% by weight, or less than 30% by weight, or less than 20% by weight, or less than 10% by weight, or less than 5% by weight, or less than 2% by weight, based on the total weight of the composition or formulation with which it is associated. In yet other preferred embodiments, component (c) is not present in the composition or formulation at all. Photoinitiator component (d)

[0072] According to the first and second aspects, the composition and / or formulation preferably comprises a photoinitiator component; i.e., a collection of one or more individual photoinitiators having one or more specific structures or types. A photoinitiator is a compound that is chemically altered by the action of light or a synergistic action between the action of light and the electronic excitation of a sensitizing dye to generate at least one of a radical, an acid, and a base. Well-known types of photoinitiators include cationic photoinitiators and free radical photoinitiators. According to one embodiment of the present invention, the photoinitiator is a free radical photoinitiator.

[0073] In one embodiment, the photoinitiator component comprises, consists of, or consists essentially of one or more acylphosphine oxide photoinitiators. Acylphosphine oxide photoinitiators are known and are disclosed, for example, in U.S. Patents 4,324,744, 4,737,593, 5,942,290, 5,534,559, 6,020,529, 6,486,228, and 6,486,226. A preferred type of acylphosphine oxide photoinitiator for use in the photoinitiator component includes bisacylphosphine oxide (BAPO) or monoacylphosphine oxide (MAPO). More specifically, it includes 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide (CAS number 84434-11-7) or 2,4,6-trimethylbenzoyldiphenylphosphine oxide (CAS number 127090-72-6).

[0074] The photoinitiator component can also optionally comprise, consist of, or consist essentially of an α-hydroxyketone photoinitiator.For example, suitable α-hydroxyketone photoinitiators are α-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenylpropanone, 2-hydroxy-2-methyl-1-(4-isopropylphenyl)propanone, 2-hydroxy-2-methyl-1-(4-dodecylphenyl)propanone, 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]-phenyl}-2-methyl-propan-1-one, and 2-hydroxy-2-methyl-1-[(2-hydroxyethoxy)phenyl]propanone.

[0075] In another embodiment, the photoinitiator component is selected from the group consisting of α-aminoketones, such as 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone, 2-benzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone, 2-(4-methylbenzyl-2-(dimethylamino)-1-[4-(4-morpholinyl)phenyl]-1-butanone or 2-benzyl-2-(dimethylamino)-1-[3,4-dimethoxyphenyl]-1-butanone; benzophenones, such as benzophenone, 2,4,6-trimethylbenzophenone, 4-methylbenzophenone, 2-methylbenzophenone, 2-methoxycarbonylbenzophenone, 4,4′-bis(chloromethyl)-benzophenone, 4-chlorobenzophenone, 4-phenylbenzophenone, 4,4'-bis(dimethylamino)-benzophenone, 4,4'-bis(diethylamino)benzophenone, methyl 2-benzoylbenzoate, 3,3'-dimethyl-4-methoxybenzophenone, 4-(4-methylphenylthio)benzophenone, 2,4,6-trimethyl-4'-phenyl-benzophenone or 3-methyl-4'-phenyl-benzophenone; ketal compounds, for example 2,2-dimethoxy-1,2-diphenyl-ethanone; and monomeric or dimeric phenylglyoxylates, for example methylphenylglyoxylates, for example 5,5'-oxo-di(ethyleneoxydicarbonylphenyl) or 1,2-(benzoylcarboxy)ethane.

[0076] Further suitable photoinitiators for use in the photoinitiator component include oxime esters, such as those disclosed in U.S. Patent No. 6,596,445. Yet another class of photoinitiators suitable for use in the photoinitiator component includes, for example, phenylglyoxalates, such as those disclosed in U.S. Patent No. 6,048,660.

[0077] In another embodiment, the photoinitiator component can comprise, consist of, or consist essentially of one or more alkyl-, aryl-, or acyl-substituted compounds not described herein above.

[0078] According to another embodiment, the composition may contain a photoinitiator that is an alkyl-, aryl-, or acyl-substituted compound. In one embodiment, the alkyl-, aryl-, or acyl-substituted photoinitiator has or is centered on an atom in a carbon (group 14) group. In such a case, upon excitation (through absorption of radiation), the group 14 atom present in the photoinitiator compound forms a radical. Thus, such compounds may generate radicals that have or are centered on an atom selected from the group consisting of silicon, germanium, tin, and lead. In one embodiment, the alkyl-, aryl-, or acyl-substituted photoinitiator is an acylgermanium compound. Such photoinitiators are described in US9708442, assigned to Covestro (Netherlands) BV, the entirety of which is incorporated herein by reference. Specific known acylgermanium photoinitiators include benzoyltrimethylgermane (BTG), tetraacylgermanium, or bisacylgermanoyl (commercially available as Ivocerin® from Ivoclar Vivadent AG, 9494 Schaan / Liechtenstein).

[0079] The photoinitiator according to the present invention can be used alone or in one or more combinations as a blend.Suitable photoinitiator blends are disclosed, for example, in US Patent No. 6,020,528 and US Patent Application No. 60 / 498,848.According to one embodiment, the photoinitiator component comprises, for example, a photoinitiator blend of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (CAS No. 162881-26-7) and 2,4,6,-trimethylbenzoylethoxyphenylphosphine oxide (CAS No. 84434-11-7) in a weight ratio of about 1:11, 1:10, 1:9, 1:8 or 1:7.

[0080] Another particularly suitable photoinitiator blend is a mixture of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone (CAS number 7473-98-5), for example in a weight ratio of about 3:1:15 or 3:1:16 or 4:1:15 or 4:1:16. Another suitable photoinitiator blend is a mixture of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone, for example in a weight ratio of about 1:3, 1:4 or 1:5.

[0081] Any suitable amount of one or more of the aforementioned photoinitiators may be used for use in the photoinitiator component in the composition according to the first aspect of the invention and may be selected alone or in combination of one or more of the types listed herein. In a preferred embodiment, the photoinitiator component comprises, consists of, or consists essentially of a free radical photoinitiator. In one embodiment, the photoinitiator component is present in an amount of about 0.1% to about 10% by weight, or about 0.1% to about 5% by weight, or about 1% to about 5% by weight, based on the total weight of the composition. Additives (e)

[0082] Compositions and / or formulations according to the first and second aspects of the invention optionally include an additive component; i.e., a collection of one or more individual additives having one or more particular structures or types. Additives are also typically added to optical fiber coatings to achieve certain desired properties, such as improved adhesion to glass optical fibers, improved shelf life, improved coating oxidative and hydrolytic stability, etc. There are many different types of desirable additives, and the invention discussed herein is not intended to be limited by these, and they are nevertheless included in the contemplated embodiments as they have desirable effects.

[0083] Examples of additives for use in the additive component include thermal inhibitors intended to prevent premature polymerization, such as hydroquinone, hydroquinone derivatives, p-methoxyphenol, β-naphthol, or sterically hindered phenols, such as 2,6-di(tert-butyl)-p-cresol. Shelf life in the dark can be increased, for example, by using copper compounds, such as copper naphthenate, copper stearate, or copper octanoate, phosphorus compounds, such as triphenylphosphine, tributylphosphine, triethyl phosphite, triphenyl phosphite, or tribenzyl phosphite, and quaternary ammonium compounds, such as tetramethylammonium chloride or trimethylbenzylammonium chloride.

[0084] To prevent atmospheric oxygen during polymerization, additives such as paraffin or similar wax-like substances can be added; these migrate to the surface at the start of polymerization due to their low solubility in the polymer and form a transparent surface layer that prevents the ingress of air. Similarly, it is also possible to apply an oxygen barrier layer.

[0085] Further potentially suitable additives include light stabilizers. Light stabilizers include UV absorbers, for example well-known commercial UV absorbers of the hydroxyphenylbenzotriazole, hydroxyphenylbenzophenone, oxalamide or hydroxyphenyl-s-triazine type. It is possible to use such compounds individually or mixtures thereof, with or without sterically hindered relatively non-basic amine light stabilizers (HALS). Sterically hindered amines are, for example, based on 2,2,6,6-tetramethylpiperidine. UV absorbers and sterically hindered amines include, for example:

[0086] 2-(2-hydroxyphenyl)-2H-benzotriazoles, such as the known commercially available hydroxyphenyl-2H-benzotriazoles and benzotriazoles, which are disclosed in U.S. Pat. Nos. 3,004,896; 3,055,896; 3,072,585; 3,074,910; 3,189,615; 3,218,332; 3,230,194; 4,127,586; 4,226,763; 4,275,004; 4,278,589; 4,315,848; 4,347,1 Nos. 80; 4,383,863; 4,675,352; 4,681,905; 4,853,471; 5,268,450; 5,278,314; 5,280,124; 5,319,091; 5,410,071; 5,436,349; 5,516,914; 5,554,760; 5,563,242; 5,574,166; 5,607,987; 5,977,219; and 6,166,218, such as 2-(2-hydroxy-5-methylphenyl) -2H-benzotriazole, 2-(3,5-di-t-butyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(2-hydroxy-5-t-butylphenyl)-2H-benzotriazole, 2-(2-hydroxy-5-t-octylphenyl)-2H-benzotriazole, 5-chloro-2-(3,5-di-t-butyl-2-hydroxyphenyl)-2H-benzotriazole, 5-chloro-2-(3-t-butyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole, 2-(3-sec-butyl-5-t-butyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(2-hydroxy-4-octyloxyphenyl)-2H-benzotriazole, 2-(3,5-di-t-amyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(3,5-bis-α-cumyl-2-hydroxyphenyl)-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-(ω-hydroxy-octa-(ethyleneoxy)carbonyl-ethyl)-,phenyl)-2H-benzotriazole, 2-(3-dodecyl-2-hydroxy-5-methylphenyl)-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-octyloxycarbonyl)ethylphenyl)-2H-benzotriazole, dodecylated 2-(2-hydroxy-5-methylphenyl)-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-octyloxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole, 2-(3-tert-butyl-5-(2-(2-ethylhexyloxy)-carbonylethyl)-2-hydroxyphenyl)-5-chloro-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-methoxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole, 2-(3-t-butyl-5-(2-(2-ethylhexyloxy)carbonylethyl)-2-hydroxyphenyl)-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenyl-2H-benzotriazole, 2,2'-methylene-bis(4-t-octyloxycarbonylethyl)phenyl 2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole, 2-(2-hydroxy-3-t-octyl-5-α-cumylphenyl)-2H-benzotriazole, 5-fluoro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole, 5-chloro-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole, 5-chloro-2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole, 2-(3-t-butyl-2-hydroxy-5-(2-isooctyloxycarbonylethyl)phenyl)-5-chloro-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-5-t-octylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3,5-di-t-octylphenyl)-2H-benzotriazole, methyl 3-(5-trifluoromethyl-2H-benzotriazol-2-yl)-5- t-Butyl-4-hydroxyhydrocinnamate, 5-butylsulfonyl-2-(2-hydroxy-3-α-cumyl-5-t-octylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3-α-cumyl-5-t-butylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3,5-di-t-butylphenyl)-2H-benzotriazole, 5-trifluoromethyl-2-(2-hydroxy-3,5-di-α-cumylphenyl)-2H-benzotriazole, 5-butylsulfonyl-2-(2-hydroxy-3,5-di-t-butylphenyl)-2H-benzotriazole and 5-phenylsulfonyl-2-(2-hydroxy-3,5-di-t-butylphenyl)-2H-benzotriazole.

[0087] Further examples include 2-hydroxybenzophenones such as 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and 2'-hydroxy-4,4'-dimethoxy derivatives.

[0088] Yet another exemplary class includes substituted and unsubstituted esters of benzoic acid, such as 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol, benzoylresorcinol, 2,4-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl 3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl 3,5-di-tert-butyl-4-hydroxybenzoate.

[0089] Suitable additional additives for use in the additive component include compounds that promote photopolymerization, such as so-called photosensitizers, which shift or broaden the spectral sensitivity of the composition in which they are incorporated. Photosensitizers include, in particular, aromatic carbonyl compounds, such as benzophenone derivatives, thioxanthone derivatives, anthraquinone derivatives and 3-acylcumarine derivatives, as well as 3-(aroylmethylene)thiazolines, and eosin, rhodamine and erythrosine dyes. Alternatively, non-aromatic carbonyl compounds may be used. An example of a non-aromatic carbonyl is dimethoxyanthracene.

[0090] The curing procedure can be particularly assisted by the use of additives that produce or promote the production of colored compositions. Such additives include pigments such as titanium dioxide, additives that form free radicals under thermal conditions, such as azo compounds such as 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), triazenes, diazosulfides, pentazadienes or peroxy compounds such as hydroperoxides or peroxycarbonates, such as t-butyl hydroperoxide, as described in US Patent No. 4,753,817. Further suitable materials for this purpose include benzopinacol compounds.

[0091] The additive component can include photoreducible dyes, such as xanthene, benzoxanthene, benzothioxanthene, thiazine, pyronine, porphyrin or acridine dyes, and / or trihalomethyl compounds that can be cleaved by radiation. Such additives are described, for example, in U.S. Patent No. 5,229,253.

[0092] Other conventional additives may be used depending on the intended application. Examples include optical brighteners, fillers, pigments, dyes, wetting agents or leveling aids. Thickly pigmented coatings may also contain glass microbeads or powdered glass fibers, as described, for example, in U.S. Pat. No. 5,013,768.

[0093] In one embodiment, the additive component includes one or more of various additives used to enhance one or more properties of the primary coating, such as antioxidants (such as Irganox 1035, thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], or tert-butylhydroquinone), adhesion promoters, inhibitors (such as acrylic acid), photosensitizers, carrier surfactants, tackifiers, catalysts, stabilizers, surface agents, and optical brighteners.

[0094] In a preferred embodiment, the additive component comprises, consists of, or consists essentially of one or more adhesion promoter compounds. The adhesion promoter provides a bond between the polymeric primary coating and the surface of the optical glass fiber. Silane coupling agents that are hydrolyzable have been used as glass adhesion promoters. Silane coupling agents are described, for example, in U.S. Pat. No. 4,932,750. In one embodiment, the adhesion promoter is a hydrolyzable silane compound that contains a mercapto group and / or multiple alkoxy groups. Such adhesion promoters are known and are described in U.S. Patent Application No. 20020013383, the relevant portions of which are incorporated herein by reference.

[0095] In one embodiment, the adhesion promoter comprises one or more of γ-mercaptopropyltrimethoxysilane, trimethoxysilylpropyl acrylate, or 3-trimethoxysilylpropane-1-thiol. Alternatively, the silane coupling group can be reacted on the oligomer in the oligomer component; in such a case, the silane coupling group is considered as part of the oligomer component, not as an additive. Thus, in one embodiment, the adhesion promoter comprises an oligomeric adhesion promoter, preferably one having a urethane group and an acrylate group. When used, the oligomeric urethane acrylate adhesion promoter preferably comprises at least two urethane groups and is the reaction product of a monofunctional telechelic urethane acrylate oligomer containing a telechelic hydroxyl group, preferably by reaction with an isocyanate silane adhesion promoter or a diisocyanate having a hydroxy, mercapto or amino functional silane.

[0096] One or more of the aforementioned additives may be used in the composition according to the present invention in any suitable amount and may be selected alone or in combination of one or more of the types listed herein. In a desirable embodiment, the additive component is present at about 0% to 40% by weight, or 0% to 30% by weight, or 0% to 20% by weight, or 0% to 10% by weight, or 0% to 5% by weight, or 0.01% to 40% by weight, or 0.01% to 30% by weight, or 0.01% to 20% by weight, or 0.01% to 10% by weight, or 0.01% to 5% by weight, or 0.1% to 2% by weight, based on the total weight of the composition. According to another embodiment, the additive component is present at 1% to 40% by weight, or 1% to 30% by weight, or 1% to 20% by weight, or 1% to 10% by weight, or 1% to 5% by weight, based on the total weight of the radiation curable composition.

[0097] As discussed above, compositions formulated according to various embodiments of the first aspect of the invention and formulations of the second aspect can be configured to have certain desirable characteristics. Specifically, such compositions and / or formulations, in addition to having low amounts of volatile diluents, can form cured products that have sufficiently low modulus values ​​and / or are fast curing. This makes such coatings and / or formulations useful for optical fiber coating applications where microbend-induced attenuation resistance and high process speeds are desirable or required. As used herein, a proxy measure of microbend-induced attenuation is the storage modulus (G'). It is known that a primary coating composition with a lower modulus imparts better resistance to microbend-induced attenuation, other things being equal. Additionally, as used herein, a proxy measure of cure speed is the time it takes for a particular coating or formulation to reach 30% of its final storage modulus value.

[0098] Thus, in various further specific embodiments, the optical fiber primary coating composition according to any of the embodiments of the first aspect, and / or the radiation curable formulation according to any of the embodiments of the second aspect, when cured into a film according to the processes and dimensions specified elsewhere herein, is configured to have a storage modulus (G') of less than 600 kPa, or from 1 to 550 kPa, or from 10 to 500 kPa, or from 300 kPa, or from 1 to 200 kPa, or from 10 to 150 kPa.

[0099] Moreover, in various other specific further embodiments, the optical fiber primary coating composition according to any of the embodiments of the first aspect, and / or other radiation curable formulations according to any of the embodiments of the second aspect, when cured into a film according to the processes and dimensions specified elsewhere herein, are configured to have a time to reach 30% of the storage modulus increase in less than 1.2 seconds, or less than 1 second.

[0100] The compositions and / or formulations of the first and / or second aspect further preferably have viscosity values ​​suitable for use in optical fiber applications and curing processes. Thus, in yet other specific further embodiments, an optical fiber primary coating composition according to any of the embodiments of the first aspect, and / or a radiation curable formulation according to any of the embodiments of the second aspect, is configured to have a viscosity of at least >0.1 Pascal seconds (Pa·s), or at least 0.2, or at least 0.5, or at least 1 Pa·s, and / or less than 15 Pa·s, or less than 12, or less than 10 Pa·s; or between 1 and 15 Pa·s, or between 2 and 12 Pa·s, or between 3 and 10 Pa·s, where the viscosity is greater than 25° C. and 2500 s. -1 The shear rate is measured.

[0101] A third aspect of the invention is a method for coating an optical fiber, comprising the steps of providing a glass optical fiber, preferably by drawing the glass optical fiber through a draw tower; applying a primary coating composition onto a surface of the glass optical fiber; optionally applying a dose of UV light sufficient to at least partially cure said primary coating composition; applying a secondary coating composition to the primary coating composition; and exposing said primary coating composition and said secondary coating composition to at least one radiation source capable of emitting ultraviolet radiation to affect curing of said primary coating composition and said secondary coating composition to form a cured primary coating on the surface of the optical fiber and to form a cured secondary coating on the surface of the cured primary coating; wherein the primary coating composition is a composition according to either an embodiment of the first or second aspect of the invention.

[0102] A fourth aspect of the invention is a coated optical fiber comprising a glass core and a cladding layer in contact with and surrounding the glass core; a coating portion, the coating portion further comprising a primary coating layer in contact with and surrounding the cladding layer; and a secondary coating layer in contact with and surrounding the primary coating layer. According to this aspect, the primary coating layer is a cured product of a radiation curable composition according to any of the embodiments of the first or second aspect, and the primary and secondary coatings are applied and cured according to any of the embodiments of the third aspect.

[0103] According to one embodiment of the fourth aspect, the optical fiber comprises a core, a cladding, a primary coating in contact with and surrounding the outer annular cladding region, and a secondary coating. According to some embodiments of the fourth aspect, the core is made of pure silica glass (SiO 2 ) or silica glass having one or more dopants that increase the refractive index of the glass core relative to pure undoped silica glass. Suitable dopants for increasing the refractive index of the core include, but are not limited to, GeO 2 , Al 2 O 3 , P 2 O 5 , TiO 2 , ZrO 2 , Nb 2 O 5 , Ta 2 O 5 and / or combinations thereof.

[0104] The cladding layer is made of pure silica glass (SiO 2 ), or the cladding is "updoped" with one or more dopants that increase the refractive index (e.g., GeO 2 , Al 2 O 3 , P 2 O 5 , TiO 2 , ZrO 2 , Nb 2 O 5 and / or Ta 2 O5 ), or where the inner cladding is "down-doped", such as with a dopant that lowers the index of refraction, such as fluorine, provided that the maximum relative refractive index of the core [Δ 1MAX ] is the maximum relative refractive index of the cladding [Δ 4MAX According to one embodiment, the cladding is also pure silica glass.

[0105] According to some embodiments of the fourth aspect, the primary coating is a typical primary coating having an in situ (or on fiber) tensile modulus of less than 1.5 MPa, or less than 1.0 MPa, or less than 0.6 MPa, or less than 0.5 MPa, or less than 0.3 MPa, or between 0.15 and 0.8 MPa, and in other embodiments less than 0.2 MPa. Methods for describing the in situ modulus are well known in the art and are described, among others, in U.S. Pat. Nos. 7,171,103 and 6,961,508, each of which is assigned to Covestro (Netherlands) BV. In one embodiment, the cured primary coating has an in situ glass transition temperature of less than -35°C, or less than -40°C, or less than -45°C, and in other embodiments, less than or equal to -50°C. Primary coatings with low in situ modulus reduce microbending, which is a coupling mechanism between modes propagating in the fiber. The low in situ glass transition temperature ensures that the in situ modulus of the primary coating remains low even when the fiber is deployed in very cold environments.

[0106] The primary coating maintains adequate adhesion to the glass fiber during thermal and hydrolytic aging, and can even be peeled off from the glass fiber for splicing purposes (if necessary). The primary coating typically has a thickness in the range of 20 to 50 μm (e.g., about 25 or 32.5 μm), with a 200 μm fiber having a smaller thickness in the range of 15 to 25 μm. In other embodiments, the primary coating preferably has a thickness of less than about 40 μm, more preferably about 20 to about 40 μm, and most preferably about 20 to about 30 μm.

[0107] The secondary coating contacts and surrounds the primary coating. The secondary coating is, for example, a polymerization product of a coating composition in which the molecules are highly crosslinked upon polymerization. According to one embodiment, the secondary coating can have an in-situ tensile modulus of greater than 800 MPa, or greater than 1110 MPa, or greater than 1300 MPa, or greater than 1400 MPa, or greater than 1500 MPa. A secondary coating with a high in-situ modulus reduces microbending, which is a coupling mechanism between modes propagating in the fiber.

[0108] According to another embodiment, the secondary coating has a high in situ modulus (e.g., greater than about 800 MPa at 25° C.) and a high T g (e.g., greater than about 50° C.). In another preferred embodiment, the in situ secondary elastic modulus is from about 1000 MPa to about 8000 MPa, more preferably from about 1200 MPa to about 5000 MPa, and most preferably from about 1500 MPa to about 3000 MPa. g The temperature is preferably from about 50° C. to about 120° C., more preferably from about 50° C. to about 100° C. In one embodiment, the secondary coating has a thickness of less than about 40 μm, more preferably from about 20 to about 40 μm, and most preferably from about 20 to about 30 μm.

[0109] Materials suitable for use in the outer (or second) coating material, as well as considerations regarding the selection of these materials, are well known in the art and are described, for example, in U.S. Patent Nos. 4,962,992 and 5,104,433 to Chapin. Alternatively, high modulus coatings have also been obtained using low oligomer content coating systems, as described in U.S. Patent No. 6,775,451 to Botelho et al. and U.S. Patent No. 6,689,463 to Chou et al. Furthermore, non-reactive oligomer components have been used to achieve high modulus coatings, as described in U.S. Patent Application Publication No. 20070100039 to Schissel et al. The secondary coating may also include inks, as is well known in the art. In such cases, the secondary coating may be referred to as a "pigmented secondary coating."

[0110] The coated optical fiber may alternatively comprise one or more additional layers disposed on the secondary layer. Most notably, such layers include separate "ink" layers that are applied and cured separately from the secondary coating. Other multi-layer coating systems are known and are disclosed, for example, in WO2017173296.

[0111] Methods for formulating typical optical fiber coatings for primary and secondary coatings for fibers as described above, as well as inks and matrix materials for curing using broadband UV lamps, are known in the art. A good discussion of this technology and the associated chemistry and test methods can be found in Section 4.6 to the end of Chapter 4 of "Specialty Optical Fibers Handbook" by A. Mendez and TF Forse, published by Elsevier, © Elsevier Inc. 2007.

[0112] In the embodiment of the third aspect of the invention, any type of optical fiber can be used. However, in a preferred embodiment, the coated optical fiber has a mode field diameter of 8-10 μm at a wavelength of 1310 nm, or a mode field diameter of 9-13 μm at a wavelength of 1550 nm, and / or a mode field diameter of 20-200 μm. 2 Such fibers may be single mode and / or large effective area fibers, given the expected demands on coating processes for these fibers that utilize higher line or processing speeds. However, other fiber types such as multimode fibers may be used as well.

[0113] A fifth aspect of the present invention is a fiber optic cable, wherein the optical fiber comprises at least one optical fiber according to any embodiment of the fourth aspect of the present invention, and / or the optical fiber is a cured product of a composition according to the first or second aspect of the present invention, and / or the optical fiber has been coated according to the third aspect of the present invention.

[0114] The improved compositions of the present invention (and coated optical fibers produced therefrom) can be formulated by selection of the components identified herein above, and can be readily tailored by one skilled in the art to which the present invention applies by following the formulation guidelines herein, as well as by extrapolating from the general approach taken in the embodiments illustrated in the following examples. Such examples below further illustrate the present invention, but, of course, should not be construed as in any way limiting its scope. EXAMPLES

[0115] These examples illustrate embodiments of the present invention. Table 1 describes the various components of the compositions used in these examples. Table 2 describes the relative amounts of the reagents described in Table 1 that were used to synthesize the oligomers used in these examples. Table 3 provides a summary of further analysis of the oligomers so characterized in Table 2, and methods for analyzing such oligomers are further described herein below. Table 1 - Ingredients

[0116] [Table 1]

[0117] Synthesis of oligomers 1-16 First, the reactor was purged with dry lean air. Then, the specific amounts from Table 2 below were charged to the reactor (equipped with a stirrer, air inlet, dropping funnel, and condenser): first, (1) BHT (e.g., 1.28 parts for Oligomer 1); then (2) applicable isocyanate (e.g., 84.29 parts TDI for Oligomer 1), followed by (3) acrylic acid (e.g., 0.08 parts for Oligomer 1). After charging, the reactor was heated to 45° C. Then, half of the specified DBTDL catalyst (e.g., 0.06 g DBTDL), followed by the hydroxyl-functional end cap (e.g., HEA, 56.08 parts in Oligomer 1) were charged to the reactor with stirring. After waiting 1 hour for the reaction to start, the temperature was increased to 60° C. At 60° C., the hydroxyl- or thiol-functional backbone component (e.g., HO-PPG 1000 -OH, 650.0 g per oligomer) and a second portion of catalyst (eg, 0.07 g) were added, after which the reaction temperature was increased to 85°C and then maintained for an additional 2 hours. After this 2 hour reaction time, the isocyanate (NCO) content was measured by potentiometric titration and found to be less than 0.1% based on the total weight of the composition. If the isocyanate content did not fall below this value, the mixture was returned to the reaction chamber for additional increments of 15 minutes (again at 85° C.) and this process was repeated to check the isocyanate content until it was within the desired range. Finally, the resulting synthetic oligomer was slowly cooled and discharged for use in the experiments described elsewhere herein. The resulting oligomers had idealized structures as shown in Table 2, with Oligomer 1 having the following idealized structure (where "T" indicates the reaction product of a diisocyanate compound and "PPG 1000 " is a polyol PPG 1000 where "H-" indicates the reaction product of the hydroxy-functional end capper HEA): HT-PPG 1000 -OH Notes for Oligomer 16: A one-pot synthesis was applied to obtain two oligomers: 80%HT-PDMS3000-OH(a)+20%HT-PDMS3000-TH(b) Oligomer 17 This oligomer was prepared using 95.32 parts Acclaim 6320N, 6.15 parts HEA, 503 parts Acclaim 8200 N, 18.97 parts TDI, 0.3 parts DBTDL, 0.824 parts BHT, 0.29 parts acrylic acid, and 190.4 parts SR489D as described in WO2021021971 (Oligomer 1 in WO2021021971). The idealized structure was as follows, where "T" represents the reaction product of the diisocyanate compound TDI, "-H" represents the reaction product of the hydroxy-functional end capper HEA, and "PPG 6000 (Triol)" represents the reaction product of polyol Acclaim 6320N): PPG 6000 (Triol)-(T-PPG 8000 -TH) 3 Oligomer 18 First, the reactor was purged with dry lean air. Then, 0.28 g of BHT, 150.77 g of Oligomer 3 (HT-PPG4000-OH), and 0.02 g of acrylic acid were placed in the reactor (equipped with an agitator, air inlet, dropping funnel, and condenser). After charging, the reactor was heated to 75° C. Then, 0.03 g of DBTDL was added, followed by 8.65 g of 3-(triethoxysilyl)propyl isocyanate, after which the mixture was stirred for an additional 2 hours. After this 2-hour reaction time, the isocyanate (NCO) content was measured by potentiometric titration and found to be less than 0.1% based on the total weight of the composition. If the isocyanate content did not fall below this value, the mixture was returned to the reaction chamber for additional increments of 30 minutes (again at 85° C.) and this process was repeated to check the isocyanate content until it was within the desired range. Finally, the resulting synthetic oligomer was slowly cooled and discharged for use in the experiments described elsewhere herein. The resulting oligomer had the following idealized structure (where "T" represents the reaction product of a diisocyanate compound and "H-" represents the reaction product of a hydroxy-functional end capper HEA): HT-PPG 4000 -OC(O)NHC 3 H 5 Si(OC 2 H 5 ) 3 Oligomer 19 First, a 500 ml reactor was purged with dry lean air. Then, 0.5 parts of BHT, 0.03 parts of acrylic acid, and 300 parts of Acclaim 4200 were charged into the reactor (equipped with a stirrer, air inlet, dropping funnel, and condenser). After charging, the reactor was heated to 85°C, and 0.06 parts of DBTDL were added at that temperature. Then, 10.07 parts of 2-isocyanatoethyl acrylate were slowly added with stirring and kept at 85°C for another 2 hours, after which the NCO content was less than 0.1%. The resulting oligomer had the following idealized structure, where "A" is an acrylate group (i.e., CH 2 CHCO 2 ) (indicating AC 2 H 4 NHC(O)O-PPG 4000 -OH 138.87 g of this intermediate oligomer (AC 2 H 4 NHC(O)O-PPG 4000 The oligomer was prepared in the same manner as described above for Oligomer 18 using 7.3 g of 3-(triethoxysilyl)propyl isocyanate (III) and 7.3 g of 3-(triethoxysilyl)propyl isocyanate. The resulting oligomer had the following idealized structure: 2 CHCO 2 ) indicating that: AC 2 H 4 NHC(O)O-PPG 4000 -OC(O)NHC 3 H 6 Si(OC 2 H 5 ) 3 Table 2 - Oligomer synthesis

[0118] [Table 2]

[0119] Table 3 - Further oligomer characterization All units are in kilodaltons unless otherwise specified.

[0120] [Table 3]

[0121] SEC characterization

[0122] Various reactive oligomers were synthesized and then evaluated by size-exclusion chromatography (SEC) according to D5296-11: "Standard Test Method for Molecular Weight Averages and Molecular Weight Distribution of Polystyrene by High Performance Size-Exclusion Chromatography" ASTM International, West Conshohocken, PA, (2011). Additionally, ASTM norm D 5226-98: "Standard Practice for Dissolving Polymer Materials" ASTM International, West Conshohocken, PA, (2010) was used to facilitate the definition of suitable solvents for polymer analysis.

[0123] Specifically, all size exclusion chromatography measurements were performed on a Waters APC (Advanced Polymer Chromatography) system equipped with an RI detector, a Wyatt microDawn multi-angle light scattering instrument, and a Wyatt microViscoStar capillary bridge differential pressure viscometer. For chromatographic separation, columns: 4.6x76mm, Acquity APC XT 450 2.5μm, 125 2.5μm, 45 1.7μm were used. The detector and columns were operated at 40°C. Before performing SEC, each polymer was dissolved in tetrahydrofuran (THF) containing 1 wt% acetic acid at concentrations ranging from 1.0 to 1.5mg / ml. This THF solution was also used as the eluent in the SEC analysis at a flow rate of 0.5ml / min.

[0124] After dissolution was complete, the molar mass and molar mass distribution were determined using the triple detection method described above using refractive index, differential viscosity, and right-angle light scattering signals. A refractive index increment (dn / dc) of approximately 0.07 ml / g was used for calculation of the molecular weight average and molar mass distribution. Specifically, the dn / dc values ​​of oligomers 1-19 were determined accordingly and are reported in units of milliliters / gram in Table 3 herein. The refractive index increment and molecular weight average, as well as the molar mass distribution, were determined by integration of the entire refractive index chromatogram. The IV-DP signal was further used to set the integration limits. The recovery of the samples from the column was 95-105%, which is typical of values ​​obtained with size exclusion chromatography.

[0125] Using the methods described above, the values ​​of Mn, Mw, Mz, and dn / dc were recorded and reported. Oligomer Tg

[0126] The glass transition temperatures (Tg) of the synthesized oligomers were measured with a Mettler Toledo DSC3+ differential scanning calorimeter. The temperature range from -80 °C to 80 °C was employed. As a result, only Tg values ​​higher than -70 °C were reliably determined. The evaluation was performed with Stare software on the first derivative of the second heating curve, using a heating rate of 10 °C / min. Formulations 1-42

[0127] Each of the formulations described in Table 4 below was prepared by conventional methods by using a 50 ml mixing cup suitable for use with a Speedmixer™. Specifically, 1 part by weight of photoinitiator BAPO and 0.25 parts by weight of Irganox 1520L were added to the amounts of ingredients specified in Table 4 below to obtain a total of 10 g for each formulation. The cup was then closed and mixed vigorously in a Speedmixer™ DAC150FVZ for 30 seconds, stopped, and mixed again in the same manner for 30 seconds.

[0128] These samples were analyzed to determine the viscosity, T 30%,弾性率最大値The viscosity values ​​were reported in Pascal seconds (Pa s), rounded to two decimal places, and the T 30%,弾性率最大値 G' is reported in kilopascals (kPa) and rounded to the nearest whole unit. The values ​​of these measured properties are reported in Table 4 below. viscosity The viscosity of the formulations was measured on a Brookfield CAP 1000 at 750 rpm and recorded after 30 seconds. The measurements were performed at 25°C and a shear rate of 2500 s. -1 The measurements were performed three times (the average values ​​are shown in Table 4 below). Maximum elastic modulus (G') and T 30%,弾性率 最大 Measurement of values

[0129] The maximum elastic modulus (G') value was determined according to the following procedure described herein. The hardware / equipment used in this procedure was as follows: Rheometer + Accessories ARESG2-Rheometer (Manufacturer: TA Instruments) APS Temperature Control Device (Advanced Peltier System) APS Standard Flat Plate (Lower Geometry) ARESG2 UV curing accessories (top plate fixture, UV light-tight back & access door, collimating optics) Φ20mm acrylic plate with UV curing option top plate fixture (upper geometry)Φ Silverline UV radiometer, UV light sensor (not calibrated), UV sensor geometry, and disposable plate holder UV light source etc. Omnicure LX500 combined with 385nm LED and 8mm lens attached Moeller Easy 412-DC-TC Control Relay (Trigger Box) UV Power Puck II (Electronic Instrumentation & Technology, calibrated)

[0130] The hardware mentioned above was then set up and arranged as follows: First, UV curing measurements were performed on an ARESG2 rheometer (TA Instruments). The rheometer was equipped with an APS temperature controller, an APS Standard Flat Plate as the lower geometry, and an ARESG2 UV curing option. The upper geometry used was the upper plate fixture from the ARESG2 UV curing option combined with a 20 mm diameter acrylic plate. As the UV light source, an Omnicure LX500 spot curing system was used in combination with a 385 nm LED (8 mm lens). The 385 nm LED was then inserted into the collimating optical lens of the ARES G2 UV curing accessory. The collimating lens was secured to the light shield and aligned to the upper UV geometry mirror, and the alignment screws were tightened. The diameter of the original 5 mm light guide holder part of the collimating lens was increased to 12 mm to accommodate the 385 nm UV-LED.

[0131] An Omnicure LX500 spot curing system was then connected to the DIGITAL I / O connector of the ARESG2 via a Moeller Easy 412-DC-TC Control Relay. The control relay served as a trigger box for the UV light source. The trigger delay time was set to 1.5 seconds, which means that the 385 nm UV-LED was automatically switched on with a delay of 1.5 seconds after the start of data collection for the elastic modulus measurement on the ARESG2. The light intensity was set to 95% and the duration of the UV light was fixed at 128 seconds.

[0132] UV light alignment: Alignment was performed before installation of the APS temperature control unit. The UV sensor geometry was mounted on a disposable plate holder and installed as the lower geometry. The UV light sensor connected to a Silverline UV radiometer was placed in the outer hole of the UV sensor geometry. The upper geometry was placed on top of the UV light sensor by applying an axial force of about 100 grams. The light intensity was then measured at four positions by rotating the lower geometry by about 90° between each successive measurement. To achieve a light distribution as equal as possible at each point, the alignment of the collimating lens was adjusted with the alignment screws on the light shield. The difference in light intensity at the four different positions was kept below 10%.

[0133] Light intensity measurements: Prior to RT-DMA measurements, UV intensity was measured using a calibrated UV Power Puck II. To accomplish this, the sensor of the UV Power Puck II was placed directly under the surface of the 20 mm acrylic plate in the top plate fixture, with the surface of the acrylic plate completely covering the sensor surface (distance <0.5 mm). The Omnicure LX500 UV source (intensity value set to 95%) was then manually turned on for 10 seconds. During these 10 seconds, the UVA2 intensity (i.e., radiation between wavelengths of 380-410 nm) was measured using the UV Power Puck II instrument. The measured UVA2 intensity was between 60-70 mW / cm. 2 The actual value was determined to be 67 mW / cm 2 It was recorded that:

[0134] Determining the actual delay time: When starting the measurements, there was a delay between the start of data sampling and the start of UV exposure. In the settings of the Moeller Easy 412-DC-TC Control Relay, the delay was set to 1.5 seconds, which means that UV exposure started 1.5 seconds after the start of data sampling.

[0135] The actual delay time of 1.519 seconds was measured using a light dependent resistor (LDR) and an oscilloscope (PicoScope 3424) and was the average of 10 individual measurements with a standard deviation of 0.004 seconds.

[0136] RT-DMA Measurements: RT-DMA UV curing measurements were then performed using an ARESG2 rheometer, APS Flat Plate, and ARESG2 UV curing accessory setup paired with an Advanced Peltier System as the temperature control device. A 385nm LED with an 8mm lens connected to an Omnicure LX500 was used as the UV light source.

[0137] Sample loading: Before loading each sample, the temperature of the bottom plate was set to 50 °C. When 50 °C was reached, the surface of the top plate (a 20 mm thick acrylic plate) was brought into contact with the bottom plate (with a gap of 0 mm) by applying an axial force of 200-400 g, allowing the top parallel plate to equilibrate to the set temperature of 50 °C. The system was allowed to further equilibrate its temperature for at least 5 minutes after the initial contact. Next, a zero fixture procedure was performed according to well-known methods to determine the gap = 0 position. After determining the gap = 0 position, the top plate was moved to a position 10 mm away. Next, a portion of each sample was transferred to the center of the bottom plate with the tip of a small spatula, after which the top geometry was lowered to a position of gap = 0.120 mm. The amount of sample had to be sufficient to ensure that the excess amount was pushed outside the gap covering the entire circumference of the top parallel plate after the top geometry was lowered to the reduced gap. The excess sample that had moved outside the gap was then removed, and the top geometry was further lowered to the measurement position (with gap = 0.100 mm). Once loaded into the measurement position, the temperature of the sample was allowed to equilibrate to 50 °C. Finally, when the sample temperature was measured stably between 49.90 and 50.10 °C, the measurement process was started by starting the trigger box (Moeller Easy 412-DC-TC) and using the interfaces and interconnections provided by the TRIOS software package.

[0138] Measurements: The actual UV-cured RT-DMA measurements were so-called "fast sampling" measurements performed at 50 °C, i.e. oscillatory fast sampling performed for 128 seconds at 50 °C with a strain of 1%, a rotation speed of 52.36 rad / s and a measurement frequency of 50 points per second (i.e. an interval of 0.020 seconds between each successive measurement point).

[0139] Measurements were then initiated via the start button in the TRIOS software. Once data sampling was initiated, the rheometer sent a signal to the control relay which in turn activated the Omnicure LX500 UV light source to irradiate each sample with the aforementioned delay of 1.519 seconds after data sampling began. Samples were illuminated with 385 nm UV light (intensity 60-70 mW / cm) during the 128 seconds of rapid sampling data collection as described above. 2 After the measurements were completed, the TRIOS data files were exported to Microsoft Excel. The samples were then removed, after which the plate was thoroughly washed with ethanol before the next sample was loaded.

[0140] Data Analysis: As mentioned above, TRIOS data was exported to Microsoft Excel. Excel was used to plot graphs and calculate various parameters for characterization of cure speed performance of the tested formulations as described below. Graphs included graphs corresponding to storage modulus (G') as a function of UV time (UV time was calculated by subtracting the delay time (1.519s) from the actual time for each data point), relative storage modulus (rel G') as a function of UV time (rel G' was calculated by the quotient of the G' value measured at a particular UV time and the maximum G' value obtained during the cure measurement). The maximum observed value of the G' graph was determined by taking the average of the G' values ​​between 110-120 seconds and is reported in Table 4 below in the column headed by "Maximum G'". For samples that were not fully cured during the test time, this column is marked with the designation "NFC", indicating that the maximum G' could not be achieved with the test procedure and time limits employed.

[0141] Meanwhile, the characteristic parameters included (1) the time to reach 30% of the total storage modulus (G') increase, and (2) the average G' of 110-120 s (the average storage modulus value of six data points toward the end of the cure measurement). The results of (1) for each compound are shown in Table 4 below. 30%,弾性率 最大 This is reported in the title block of the report. Table 4 All amounts are in parts by weight.

[0142] [Table 4] TIFF2025514927000005.tif34168

[0143] Discussion of results

[0144] As can be seen, compositions according to various aspects of the present invention tend to have properties that make them particularly suitable for use in optical fiber coating applications, particularly as optical fiber primary coatings. First, it is apparent that compositions that contain little or no reactive diluents (EOEOA, DMA, and / or nVC are used in the above examples) are more preferred for use in optical fiber coating applications in that, all other things being equal, the volatile content is minimized.

[0145] Furthermore, compositions having such low volatile content are particularly advantageous in terms of cure speed (low T 30%,弾性率 最大 It has been shown that the compositions can be configured in a variety of different ways to exhibit further suitability for use in optical fiber coating applications in terms of low elastic modulus (as measured by G-value, particularly less than 1.2 seconds, more preferably less than 1.0 seconds), low elastic modulus (as measured by G-value, particularly less than 600 kPa, more preferably less than 500 kPa, more preferably less than 400 kPa, more preferably less than 300 kPa), and / or low viscosity (particularly less than 9 Pascal-seconds, more preferably less than 5 Pascal-seconds).

[0146] The aforementioned effects are demonstrated using a variety of oligomer types, amounts, combinations, and diluents.

[0147] Unless otherwise specified, the term weight percent refers to the amount by weight of a particular component relative to the total liquid radiation curable formulation in which it is incorporated.

[0148] The use of the terms "a" and "an" and "The" and similar referents in the context of describing the present invention (particularly in the context of the accompanying claims) should be construed to include both the singular and the plural, unless otherwise indicated herein or clearly contradicted by the context. The terms "comprises," "has," "includes," and "comprises" are construed as open-ended terms (i.e., meaning "including, but not limited to"), unless otherwise indicated. The recitation of numerical ranges herein is intended merely to serve as a shorthand method for individually referring to each value falling within the range, unless otherwise indicated herein, and each value is incorporated into the specification as if it were individually recited herein. All methods described herein may be performed in any suitable order, unless otherwise indicated herein or clearly contradicted by the context. Any examples or exemplary language used herein (e.g., "etc.") are intended merely to better illustrate the present invention and do not pose limitations on the scope of the present invention, unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[0149] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of these preferred embodiments may become apparent to those of skill in the art upon reading the foregoing description. The inventors expect that such variations will be accommodated by those of skill in the art, and intend to practice the invention otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, all combinations of the above-described elements in all possible variations thereof are encompassed by the present invention unless otherwise indicated herein or clearly contradicted by context. Although the present invention has been described in detail with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention as claimed.

Claims

1. A primary coating composition for optical fibers, wherein the weight of the entire primary coating composition is: (a) One or more oligomers which are reaction products of (iii) a hydroxyl-functional end capper further comprising an ethylenically unsaturated moiety between 60% and 99% by weight, (ii) an isocyanate compound, and (i) a hydroxyl-functional or thiol-functional main chain compound; Here, the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl and thiol groups in (i) is 1.0 or less; (b) Optionally, one or more urethane (meth)acrylate oligomers other than those in (a); (c) Optionally, one or more reactive diluent monomers; (d) One or more photoinitiators; (e) Optionally, one or more additives A primary coating composition for optical fibers, comprising [a specific component].

2. The optical fiber primary coating composition according to claim 1, wherein, in the absence of (b), one or more oligomers described in (a) have at least two ethylenically unsaturated groups, more preferably two ethylenically unsaturated groups.

3. The optical fiber primary coating composition according to claim 1, wherein one or more oligomers described in (a) are present in an amount of 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more and 96% by weight or less, and (i) comprises a polyether, polyester, polybutadiene, polycarbonate or silicone portion.

4. The optical fiber primary coating composition according to claim 1, wherein the hydroxy-functional or thiol-functional main chain compound (i) comprises a polyether polyol, preferably polypropylene glycol.

5. The optical fiber primary coating composition according to claim 1, wherein the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl groups and thiol groups in (i) is 2 / 3 or more.

6. The oligomer described in (a) has 1.8 to 2.2 urethane bonds, and further / or (a) One or more oligomers have a diblock or triblock structure, The optical fiber primary coating composition according to claim 1.

7. The optical fiber primary coating composition according to claim 1, wherein one or more oligomers described in (a) have a number average molecular weight (Mn) of 1,000 g / mol to 10,000 g / mol, preferably 1,200 g / mol to 9,000 g / mol.

8. The optical fiber primary coating composition according to claim 1, wherein one or more oligomers described in (a) are terminated with a hydroxyl group at one end and optionally terminated with a silane group.

9. The optical fiber primary coating composition according to claim 1, wherein one or more oligomers described in (a) end with a hydroxyl group at one end.

10. The optical fiber primary coating composition according to claim 1, wherein the (iii) hydroxyl-functional end capper further comprises one or two ethylenically unsaturated moieties, preferably the (iii) hydroxyl-functional end capper further comprises one ethylenically unsaturated moiety.

11. (i) The optical fiber primary coating composition according to claim 1, wherein the hydroxyl-functionalized main chain compound comprises at least two hydroxyl groups, or at least three hydroxyl groups, or four hydroxyl groups.

12. The optical fiber primary coating composition according to claim 1, wherein one or more oligomers described in (a) comprises a reaction product of a single PPG diol as (i); a single diisocyanate compound as (ii); and a hydroxyl-functionalized (meth)acrylate compound as (iii).

13. The optical fiber primary coating composition according to claim 1, wherein the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl groups in (i) is equal to 1.

0.

14. The optical fiber primary coating composition according to claim 1, wherein (ii) comprises, essentially consists of, or comprises isophorone diisocyanate, 2,4-isomerized toluene diisocyanate, 4,4'-methylenedicyclohexyl diisocyanate, 1,5-pentane diisocyanate, 2,2,4-trimethyl-hexamethylene diisocyanate, 2,4,4-trimethyl-hexamethylene diisocyanate, or hexamethylene diisocyanate, or a combination thereof.

15. The optical fiber primary coating composition according to claim 1, wherein (iii) comprises, essentially consists of, or comprises hydroxyethyl methacrylate, hydroxyethyl acrylate, 2-hydroxypropyl methacrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 4-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, caprolactone methacrylate, caprolactone acrylate, glycerol acrylate methacrylate, glycerol dimethacrylate, glycerol diacrylate, or a combination thereof.

16. One or more urethane (meth)acrylate oligomers (b) are present in an amount of 29.95% by weight or less, and (b) also includes reaction products of (i) a hydroxyl-functional main chain compound, (ii) an isocyanate compound, and (iii) a hydroxyl-functional end capper. In the urethane (meth)acrylate oligomer (b), the molar ratio of the number of isocyanate groups in (ii) to the number of hydroxyl groups in (i) is greater than 1.0, and more preferably about 1.5 to about 2.

0. The optical fiber primary coating composition according to claim 1.