A radiation-curable composition containing a polyfunctional long-arm oligomer for coating an optical fiber

Abstract

Disclosed and claimed herein are radiation-curable compositions for coating optical fibers, comprising an oligomer, a diluent, a photoinitiator, and optionally additives. The oligomer comprises a reactive urethane oligomer having at least three arms, each arm having a farthest end and bound together at a single junction, at least one arm comprising the reaction product of a polyol, a polyisocyanate, and an isocyanate-reactive (meth)acrylate. The reactive urethane oligomer may have a specific molecular weight and / or average functionality value and a specific chain length value along one or more arms between the oligomer junction and the far end. Also disclosed are coated optical fibers and cables made therefrom, as well as methods of coating optical fibers incorporating the compositions described herein.

Description

Detailed Description of the Invention

[0001] [Technical Field]

[0001] The present invention generally relates to a method for coating an optical fiber, a radiation curable primary coating suitable for use on an optical fiber having a polyfunctional long arm oligomer, and a coated optical fiber produced therefrom.

[0002] [Cross - Reference to Related Applications]

[0002] This application claims priority based on U.S. Provisional Patent Application No. 62 / 880679, filed on July 31, 2019 (which is hereby incorporated by reference in its entirety as if fully set forth herein).

[0003] [Background]

[0003] An optical fiber is composed of a glass fiber obtained by thermal melting spinning of glass and one or more coating layers disposed on the glass fiber for protection and strengthening. The optical fiber is manufactured, for example, by first forming a flexible primary coating layer on the surface of the glass fiber and then forming a more rigid secondary covering layer called a secondary coating on the primary coating. Also known are tape - like optical fibers or optical fiber cables having an optical fiber with a plurality of coating layers bound with a binding material.

[0004]

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

[0005]

[0005] The relatively soft inner primary coating provides resistance to undesirable microbending that results in increased attenuation (i.e., signal loss) of signal transmission in the coated optical fiber. Microbending refers to microscopic curvature of the optical fiber involving local axis displacement of a few micrometers and a spatial wavelength of a few millimeters. Microbending can be induced by thermal stress and / or mechanical lateral forces. The coating can provide lateral force protection that protects the optical fiber from microbending, but the amount of protection provided decreases with decreasing coating thickness.

[0006]

[0006] The primary coating preferably has a higher refractive index than the cladding of the associated optical fiber to enable removal of stray optical signals away from the core of the optical fiber. The primary coating should maintain proper adhesion to the glass fiber during thermal aging and hydrolysis aging and, if desired, should be peelable therefrom for splicing purposes. The primary coating typically has a thickness in the range of 20 to 50 μm (e.g., about 25 or 32.5 μm), and a thinner thickness in the range of 15 to 25 μm for 200 μm fibers.

[0007]

[0007] The harder secondary coating provides resistance to handling forces such as those encountered during ribbonization and / or cabling of the coated optical fiber. Radiation-curable optical fiber secondary coating compositions generally also include a mixture of ethylenically unsaturated compounds including one or more acrylate-functional oligomers dissolved or dispersed in a liquid ethylenically unsaturated diluent and a photoinitiator. The coating composition is typically applied to the optical fiber in liquid form and then cured by exposure to actinic radiation.

[0008]

[0008] In the methods commonly used to form a covering layer on glass fibers, for example, the glass fibers are coated with a liquid curable resin composition and cured by heat or light, especially ultraviolet light. Optical fiber coatings are typically applied using one of two processes, wet-on-wet (WOW) and wet-on-dry (WOD), including a primary layer and a secondary layer. In the WOD process, the fiber is first subjected to primary coating application and cured by exposure to UV light. The fiber is then subjected to secondary coating application and subsequently cured by similar means. In the WOW process, the fiber is subjected to both primary coating application and secondary coating application, and then the fiber proceeds to the curing step. In the wet-on-wet process, the curing lamp between primary coating application and secondary coating application is omitted.

[0009]

[0009] Radiation curable compositions for optical fibers are known, but it would be desirable to provide a coating composition, especially a primary coating composition, formulated to impart increased toughness and / or tear strength when applied and cured on glass optical fibers. Additionally or alternatively, it would be desirable to provide such a coating composition that can contribute to the manufacture of coated optical fibers having excellent microbend resistance approximated by those having a low elastic modulus value.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

[0011] [Simple Summary]

[0013] This specification describes several aspects and embodiments of the present invention. A first aspect is a radiation-curable composition for coating an optical fiber, comprising an oligomer component, a diluent component, a photoinitiator component, and optionally an additive component, wherein the oligomer component comprises, consists essentially of, or consists of a reactive urethane oligomer having at least three arms each having a distal end and bound and integrated at a single junction point, and at least one arm comprises a reaction product of a polyol, a polyisocyanate, and an isocyanate-reactive (meth)acrylate, and the reactive urethane oligomer has a number average molecular weight (Mn) and a Z average molecular weight (Mz), wherein Mn is about 10 kilodaltons (kDa) or more and Mz / Mn is 4.5 or more.

[0012]

[0014] In another embodiment according to the first aspect, the oligomer component has the following structure (I): [Chemical formula] (wherein P1 represents the reaction product of a polyether triol, P2 represents the reaction product of a polyether diol, I1 and I2 are the same or different and each represents the reaction product of a diisocyanate compound, and R1, R2, and R3 are the same or different and at least one of them is (a) a hydroxy-functional (meth)acrylate or (b) a reaction product of a C1-C 18 or C2-C 12 or C4-C 10 monohydric alcohol having no (meth)acrylic moiety) and comprises, consists of, or consists mainly of one or more oligomers represented by. In a preferred embodiment, at least one of R1, R2, and R3 represents the reaction product of (a).

[0013]

[0015] A second aspect of the present invention preferably provides a glass optical fiber by drawing the glass optical fiber through a drawing tower, applying a primary coating composition onto the surface of the glass optical fiber, optionally applying an amount of UV light irradiation sufficient to at least partially cure the primary coating composition, applying a secondary coating composition onto the primary coating composition, and exposing the primary coating composition and the secondary coating composition to at least one radiation source capable of emitting ultraviolet rays to cause curing of the primary coating composition and the secondary coating composition, thereby forming a cured primary coating on the surface of the optical fiber and a cured secondary coating on the surface of the cured primary coating. A method of coating an optical fiber, wherein the primary coating composition is a composition according to any of the embodiments of the first aspect of the present invention.

[0014]

[0016] A third aspect of the present invention is a coated optical fiber, the coated optical fiber comprising a glass core, a cladding layer in contact with and surrounding the glass core, and 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 third aspect, the primary coating layer is a cured product of a radiation-curable composition according to any of the embodiments of the first aspect, and the primary and secondary coatings are applied and cured according to any of the embodiments of the second aspect.

[0015]

[0017] According to an embodiment of the third aspect, the coated optical fiber has a specific tearing strength (G0) value, for example, at least 10 J / m 2 , or at least 15 J / m 2 , or at least 20 J / m 2It has. According to another embodiment, the coated optical fiber has a film elastic modulus of less than 1.5 MPa, or less than 1.0 MPa, or less than 0.6 MPa. In yet a further embodiment, the coated optical fiber has a ratio of G0 value (J / m 2 unit) to film elastic modulus value (in MPa units) greater than 70 or greater than 81.

[0016]

[0018] A fourth aspect of the present invention is an optical fiber cable, wherein the optical fiber includes at least one optical fiber according to the third aspect of the present invention, and / or the optical fiber is a cured product of the composition according to the first aspect of the present invention, and / or the optical fiber is coated according to the second aspect of the present invention, which is an optical fiber cable.

[0017] [Detailed Description]

[0019] The first aspect of the present invention is an oligomer component, a diluent component, a photoinitiator component, optionally an additive component, and is a radiation-curable composition for use as an optical fiber primary coating, comprising, consisting of, or consisting essentially of the oligomer component includes, consists essentially of, or consists of a reactive urethane oligomer having at least three arms each having a distal end and bound together at a single junction point, and at least one arm is a polyol, a polyisocyanate, an isocyanate-reactive (meth)acrylate, and contains the reaction product of the reactive urethane oligomer has a number average molecular weight (Mn) and a Z average molecular weight (Mz), Mn is at least about 10 kilodaltons (kDa), and Mz / Mn is at least 4.5, which is a radiation-curable composition.

[0018]

[0020] The radiation-curable composition for coating an optical fiber according to the first aspect of the present invention contains an oligomer component, a diluent component, a photoinitiator component, and optionally an additive component. In a preferred embodiment, the radiation-curable composition for coating an optical fiber according to the first aspect of the present invention consists of a reactive oligomer component, a reactive diluent monomer component, a photoinitiator component, and an additive component containing an adhesion promoter. The following-described components can be used in the composition according to the first aspect, the composition used in the method for coating an optical fiber according to the second aspect, and the composition cured as a coating described in relation to the coated optical fiber according to the third aspect, in any of the aspects of the present invention for the radiation-curable composition.

[0019] [Oligomer component]

[0021] The radiation curable composition according to the present invention includes an oligomer component, that is, one or more individual oligomers of a group having one or more specific structures or types. As used herein, an oligomer means a molecule of intermediate relative molecular mass having a structure containing a plurality of units actually or conceptually derived from molecules of lower relative molecular mass. When used herein, preferably when measured by the size exclusion chromatography (SEC) method described elsewhere in this specification, if it further has a number average molecular weight (Mn) of more than about 1 kilodalton (kDa), the component is regarded as an oligomer. In certain embodiments, the oligomer component comprises, consists of, or consists essentially of one or more oligomers having an Mn of at least 20 kDa, or at least 30 kDa, or at least 40 kDa, or 20 to 150 kDa, or 20 to 130 kDa, or 20 to 100 kDa, or 30 to 80 kDa, or 35 to 55 kDa. According to other embodiments, the oligomer component comprises, consists of, or consists essentially of one or more oligomers having a theoretical molecular weight (Mn,theo) of at least 10 kilodaltons (kDa), more preferably more than 12 kDa, more preferably more than 15 kDa, more preferably more 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 15 to 120 kDa, or 20 to 120 kDa, or 25 to 120 kDa, or 25 to 110 kDa, or 25 to 100 kDa.

[0020]

[0022] The oligomer component includes one or more reactive oligomers. As used herein, "reactive" means the ability to form a chemical reaction, preferably a polymerization reaction, with other molecules. For this reason, a reactive compound would be said to have at least one reactive group or functional group. Such a reactive group or functional group is preferably a polymerizable group. Although some non-reactive oligomers may be contemplated for use in the present invention, a high percentage of reactive oligomers is advantageous. In certain embodiments, the oligomer component consists of or consists essentially of reactive oligomers.

[0021]

[0023] The reactive oligomer component according to the present invention 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 can be of any known type. However, in certain embodiments, the polymerizable group can 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 olefinic double bonds.

[0022]

[0024] The polymerizable group can occur at any feasible location along the length of the reactive oligomer, such as a polymerizable backbone group or a polymerizable end group. The polymerizable backbone group is present along the length of the oligomer or is a branch from a straight chain along the length, while the polymerizable end group is a polymerizable group present at the end of the oligomer. The polymerizable group can be present, for example, at the end of the oligomer (synonymously referred to as the "end point" herein), in a branched pattern, a fork-like pattern, etc., spaced apart from or directly or indirectly adjacent to other polymerizable groups. In a preferred embodiment, the polymerizable group comprises, consists essentially of, or consists of a polymerizable end group.

[0023]

[0025] The reactive oligomer according to the present invention can be of any known type that conforms to the definitions specified elsewhere in this specification. However, according to a first aspect, the oligomer component comprises, consists of, or consists essentially of one or more urethane oligomers, preferably reactive urethane oligomers. The urethane oligomer contains at least one urethane group or moiety and preferably contains at least a backbone, a polymerizable group, and a urethane group linking the backbone to the polymerizable group. According to the first aspect, the urethane oligomer comprises the reaction product of a polyol, a polyisocyanate, and an isocyanate-reactive (meth)acrylate.

[0024]

[0026] Examples of suitable polyol compounds include polyether polyols, polyester polyols, polycarbonate polyols, polycaprolactone polyols, acrylic polyols, and other polyols. These polyols can be used individually or in combinations 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 polypropylene glycol (PPG). As used herein, compounds derived from polypropylene glycol include end-capped PPG such as EO end-capped PPG. The polymerization method of the structural units in these polyols is not particularly limited. Each of random polymerization, block polymerization, or graft polymerization is acceptable.

[0025]

[0027] As used herein, a block copolymer means a portion of an oligomer or polymer that contains many constitutional units and includes a feature in which at least one constitutional unit is not present in an adjacent portion. As used herein, mono-, di-, and triblock copolymers mean the average number of specific blocks present in the oligomer. In a preferred embodiment, a specific block means a polyether block derived from one or more of the polyols described elsewhere herein, preferably a polyether polyol. In one embodiment, the blocks meant by the mono-, di-, and / or triblock copolymers are polyether blocks derived from one or more of the polyols described elsewhere herein. In one embodiment, a monoblock copolymer can be described as a copolymer having on average only about 1 unit or less than about 0.9 to 1.5 units of a specific block, such as a polyether block. In one embodiment, a diblock copolymer can be described as a copolymer having on average about 2 units or at least 1.5 to less than 2.5 units of a specific block, such as a polyether block. In one embodiment, a triblock copolymer can be described as a copolymer having on average about 3 units or at least 2.5 to less than 3.5 units of a specific block, such as a polyether block. The number of polyether units in a given oligomer can be determined by the number of polyether polyol molecules utilized in the synthesis of a single oligomer.

[0026]

[0028] 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 ion-polymerizable cyclic compounds. Here, examples of ion-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 ion-polymerizable cyclic compounds include combinations that produce binary copolymers, such as tetrahydrofuran and 2-methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, and tetrahydrofuran and ethylene oxide, and combinations for producing terpolymers, such as combinations of tetrahydrofuran and 2-methyltetrahydrofuran and ethylene oxide, and combinations of tetrahydrofuran and butene-1-oxide and ethylene oxide. The ring-opening copolymers of these ion-polymerizable cyclic compounds can be either random copolymers or block copolymers.

[0027]

[0029] These polyether polyols include, for example, 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.), P710R, P1010, P2010, and 1044 Pluracol® P series (manufactured by BASF), Acrol® and Acclaim® series, for example, PPG725, PPG1000, PPG2000, PPG3000, PPG4000, and PPG8000, and further the Multranol® series, for example, PO / EO polyether diols having Mw of 2800 or 40000 (manufactured by Covestro), etc., which are commercially available products. In addition, AGC Chemicals provides diols under the trade names of Preminol®, for example, Preminol S4013F (Mw 12,000), Preminol 4318F (Mw 18,000), and Preminol 5001F (Mw 4,000).

[0028]

[0030] The polyester diol obtained by the reaction of a polyhydric alcohol and a polybasic acid is an example of a polyester polyol. Examples of polyhydric alcohols include ethylene glycol, polyethylene glycol, tetramethylene glycol, polytetramethylene glycol, 1,6 - hexanediol, 3 - methyl - 1,5 - pentanediol, 1,9 - nonanediol, 2 - methyl - 1,8 - octanediol, and the like. Examples of polybasic acids include phthalic acid, dimer acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, adipic acid, sebacic acid, and the like.

[0029]

[0031] 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.).

[0030]

[0032] Triols such as polyester triols and polyether triols are also known. Particularly preferred for use herein are oligotriols having the general formula: A(-----OH)3, where A is a chemical organic structure, such as an aliphatic structure, a cycloaliphatic structure, an aromatic structure, or a heterocyclic structure, and "-----" is an oligomeric chain, such as, by way of example, a polyether chain, a polyester chain, a polyhydrocarbon chain, or a polysiloxane chain, and "OH" is a terminal hydroxy group. In certain embodiments, 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, PO, EO, or a copolymer of PO and EO having an MW of 500 to 15,000 daltons with EO in the terminal block or internal block. 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, and having a molecular weight of about 500 to 15,000 g / mol. In a preferred embodiment, the triol is derived from a bio-based or natural reactant, such as a particular vegetable oil.

[0031]

[0033] Examples of commercially available suitable triols include related propylene oxide - based polyether triols available from Carpenter under the trade name Carpol® GP, 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 those of the brand Arcol®, such as Arcol LHT - 240 (molecular weight “Mw” specified by the manufacturer as approximately 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), those of 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 further those of the trade name Acclaim®, such as Acclaim 703 (Mw 700 g / mol), Acclaim 3300N (Mw 3000 g / mol), Acclaim 6300 (Mw 6000 g / mol), and Acclaim 6320 (Mw 6000 g / mol), which are commercially available from Covestro. In addition, AGC Chemicals offers triols under the trade name Preminol®, such as Preminol S3011 (Mw 10,000 g / mol), Preminol 7001K (Mw 7,000 g / mol), and Preminol 7012 (Mw 10,000 g / mol).

[0032]

[0034] The theoretical molecular weights derived from the hydroxyl values of these polyols are usually from about 50 g / mol to about 15,000 g / mol, preferably from about 500 to 12,000 g / mol, or from about 1,000 to about 8,000 g / mol.

[0033]

[0035] (Poly) isocyanate compounds, preferably the reaction products of diisocyanate compounds, can be used for the preparation of urethane groups or moieties in the reactive urethane oligomers according to the first 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, methylene bis(4-cyclohexyl isocyanate), 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, lysine isocyanate, and the like.

[0034]

[0036] These diisocyanate compounds can be used either individually or in combinations of two or more. Preferred diisocyanates are isophorone diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, and hexamethylene diisocyanate, 2,4-tolylene diisocyanate and 2,6-tolylene diisocyanate.

[0035]

[0037] As used herein, "polyisocyanate" means that the isocyanate compound has two or more isocyanate moieties per molecule. In certain embodiments, the oligomeric component comprises, consists essentially of, or consists of a urethane oligomer that is a reaction product of one or more polyisocyanates. In addition to the diisocyanates identified 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 trimers, which are commercially available from Covestro under the trade name Desmodur® and include, but are not limited to, Desmodur N3200, Desmodur N3300, Desmodur N3390, Desmodur N3600, Desmodur N3800, Desmodur N3900, Desmodur N XP2580, Desmodur XP2599, Desmodur XP2675, Desmodur XP2731, Desmodur XP2714, and Desmodur XP2803.

[0036]

[0038] Further commercially available triisocyanates include Vestanat® T (IPDI trimer) and polyisocyanate crosslinkers of the HT (HDI trimer) series for 2k systems available from Evonik.

[0037]

[0039] The urethane oligomer also includes the reaction product of an isocyanate-reactive (meth)acrylate. Any suitable (meth)acrylate can be used, including monomers and oligomers, but (meth)acrylate monomers are preferred. Such isocyanate-reactive (meth)acrylates preferably include hydroxyl group-containing (meth)acrylate compounds. This is because such compounds are known to be reactive with isocyanates, including polyisocyanates. Examples of hydroxyl group-containing (meth)acrylates include (meth)acrylates derived from (meth)acrylic acid and epoxy, and (meth)acrylates containing alkylene oxide, 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).

[0038]

[0040] In certain embodiments, the urethane oligomer also includes the reaction product of a non-functional end-capper. Such compounds form a terminal end along at least one arm of the urethane oligomer when reaction-introduced into the oligomer via a (poly)isocyanate compound and / or an isocyanate-reactive (meth)acrylate, along which no other polymerizable groups are present. Non-functional end-cappers can include non-UV curable compounds having an active hydrogen group, such as mercapto group-containing (-SH) compounds, amino group-containing (-NH2) compounds, and hydroxyl group-containing compounds.

[0039]

[0041] In a preferred embodiment, the urethane oligomer comprises a reaction product of a monohydric alcohol having no (meth)acrylic moiety. Such a compound is preferably reactive with the above-described (poly)isocyanate. The monohydric alcohol having no (meth)acrylic moiety can end-cap the oligomer with a hydroxyl group to render its arms or chains non-polymerizable. Further, according to this method, the oligomer can have more arms than functional groups. A three-arm oligomer in which one arm is end-capped with one hydroxyl group and the other two arms are end-capped with (meth)acrylic groups will be referred to herein as a three-arm difunctional oligomer.

[0040]

[0042] In one embodiment, the urethane oligomer component comprises, consists of, or consists essentially of at least one reactive urethane oligomer having at least one arm or two arms or three arms or more than three arms end-capped with a hydroxyl group. In one embodiment, the end-capping hydroxyl group is a reaction product of a monohydric alcohol compound having no (meth)acrylic moiety.

[0041]

[0043] In one embodiment, the monohydric alcohol compound having no (meth)acrylic moiety is a C1-C 18 or C2-C 12 or C4-C 10 aliphatic compound such as a linear or branched monohydric alcohol.

[0042]

[0044] Any suitable monohydric alcohol having no (meth)acrylic moiety can be used, but in a preferred embodiment, the monohydric alcohol having no (meth)acrylic moiety comprises, consists of, or consists essentially of methanol, ethanol, isopropyl alcohol, butanol, pentanol, 2-ethylhexanol, cetyl alcohol, geraniol, inositol, menthol, or any combination thereof.

[0043]

[0045] When reacting the components used to prepare the urethane oligomer, preferably one or more urethanization catalysts are also used. Examples of such catalysts include copper naphthenate, cobalt naphthenate, zinc naphthenate, bismuth, di-n-butyltin dilaurate, triethylamine, and triethylenediamine-2-methyltriethylenediamine. The catalyst can be used in any suitable amount, for example, about 0.01 to about 1 wt.% of the total amount of the reactants. The reaction can be carried out at any suitable temperature, for example, a temperature of about 10 to about 90 °C, preferably about 30 to about 80 °C.

[0044]

[0046] In certain embodiments, the urethane oligomer comprises a difunctional reactive urethane oligomer. As used herein, difunctional means having an average of 1.5 to 2.5 polymerizable groups per molecule, as determined, for example, by nuclear magnetic resonance spectroscopy (NMR). However, in other embodiments, the oligomer component comprises, consists essentially of, or consists of a trifunctional reactive urethane oligomer or an oligomer having an average of more than 2.5 to 3.5 polymerizable groups per molecule. In another embodiment, the oligomer component comprises a tetrafunctional oligomer or one having an average of more than 3.5 to 4.5 polymerizable groups per molecule. In a preferred embodiment, the oligomer 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 certain embodiments, the average (meth)acrylate functionality of the oligomer 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.

[0045]

[0047] The urethane oligomer component according to the first aspect of the present invention preferably comprises, consists essentially of, or consists of one or more types of reactive urethane oligomers having at least three arms or exactly three arms, each arm having a terminus, and each of the three arms being bound and integrated at a single junction. As used herein, an arm means a branch or straight chain of bonding atoms arising from a point, main chain, backbone, or central structure. Such an arm has a terminal or several termini at the end of a chain or branch that is not covalently bonded to other atoms in the unpolymerized state. As used herein, "junction" or "junction point" means any position along a structure where two or more arms intersect. As an example, glycerol has a junction point located at the central carbon atom to which all three arms terminating in hydroxyl groups are connected, as shown below.

Chemical formula

[0046]

[0048] However, in the case of star polymers, taking into account that the arms of the star polymer cannot cross directly, the junction will be located in the central core structure. Regardless, the oligomer having at least three arms according to the first aspect of the present invention may be of any suitable type, but a branched oligomer is preferred. The basic polymer structure is discussed in Chapter 1 of Rudin et al., The Elements of Polymer Science & Engineering (Third Edition), 2013. In certain embodiments, the oligomer having at least three arms is a star oligomer of a branched oligomer consisting of several straight chains linked to a central core. The star oligomer can have any suitable oligomeric architecture, including star-block copolymers, asymmetric, and miktoarm subtypes. Various star polymers and their syntheses are discussed in M. Pitsikalis, Reference Module in Chemistry, Molecular Sciences and Chemical Engineering, 2013.

[0047]

[0049] In a preferred embodiment, the junction points of the reactive urethane oligomers are located along the reaction product of the trifunctional core compound. This trifunctional core compound can easily facilitate the synthesis of reactive urethane oligomers having three arms. In another embodiment, the trifunctional core compound comprises, consists of, or consists essentially of a triisocyanate compound. In another embodiment, this trifunctional core compound comprises, consists of, or consists essentially of a triol such as a polyether triol. In certain embodiments, the triol has three individual arms even before oligomer synthesis, and thus contributes to the formation of the three individual arms of the oligomer in addition to its junction points. In certain embodiments, the theoretical molecular weight of one, more than one, or all of the arms of the trifunctional core compound is at least 2 kDa, or at least 3 kDa, or at least 5 kDa, or 2 - 10 kDa, or 2 - 8 kDa, or 2 - 7 kDa, or 3 - 10 kDa, or 3 - 7 kDa. In certain embodiments, the triol has a theoretical molecular weight of at least 3 kDa, or at least 5 kDa, or at least 6 kDa, or at least 9 kDa, or 5 kDa - 35 kDa, or 5 kDa - 30 kDa, 5 kDa - 20 kDa, or 6 kDa - 15 kDa.

[0048]

[0050] Regardless of whether the trifunctional or triol core compound contributes to the formation of one or more arms, at least one arm of the reactive urethane oligomer according to the first aspect of the present invention comprises the reaction product of a polyol, a polyisocyanate, and an isocyanate-reactive (meth)acrylate. In other embodiments, at least two arms or three arms comprise the reaction product of such reactants. In certain embodiments, the reactive urethane oligomer comprises the reaction product of a polyol, a polyisocyanate, and a monohydric alcohol having no (meth)acrylic moiety. In certain embodiments, the reactive urethane oligomer also comprises, if any, the reaction product of a urethanization catalyst. Suitable examples of polyols, polyisocyanates, isocyanate-reactive (meth)acrylates, monohydric alcohols having no (meth)acrylic moiety, and urethanization catalysts are described elsewhere in this specification above.

[0049]

[0051] In a preferred embodiment, the reactive urethane oligomer according to the first aspect, having at least three arms each having a farthest end point and bound and integrated at a single junction point, has a specific chain length between the junction point and the farthest end point along the three arms of the reactive urethane oligomer. As used herein, "chain length" is defined as the atomic weight of all individual atoms directly linked between two specific points along the chain. Referring again to the glycerol example used above, the chain lengths between the junction point and the three end points are 31, 17, and 31 atomic units, respectively, from left to right in the above figure.

[0050]

[0052] According to the first aspect of the present invention, the oligomer component includes a reactive urethane oligomer having at least three arms each having a farthest end point and bound and integrated at a single junction point, and the chain length between the junction point and the farthest end point along the three arms of the reactive urethane oligomer is at least 3 kilodaltons (kDa), or at least 4 kDa, or at least 5 kDa, or at least 6 kDa, or at least 7 kDa, or at least 8 kDa, or at least 10 kDa, and at most 60 kDa, or at most 50 kDa, or at most 40 kDa, or at most 35 kDa, or preferably 4 kDa to 35 kDa. Longer chain lengths are preferred, but if they become too long, the viscosity of the radiation-curable composition to which they are related may become too high, and it may not be possible to immediately promote the processability of the optical fiber coating.

[0051]

[0053] Compositions having such "long-arm" oligomers, especially those having long-arm trifunctional oligomers, are suitable for use in optical fiber coating applications and further impart industrially desirable properties to the coatings produced therefrom, as discovered by the inventors. Without wishing to be bound by any theory, the inventors theorize that such long-arm oligomers form "polymer loops" upon application and curing. These polymer loops form knots and entangle, facilitating the production of optical fiber coatings having improved tear strength. Thereby, the cavitation resistance of the optical fiber coating will be advantageously improved. Surprisingly, it has been observed that such oligomers can contribute to this improvement without sacrificing (i.e., without significantly increasing) the desirable low elastic modulus value, which is also an important feature of modern high-performance optical fiber primary coatings. It is hypothesized that the three arms on the oligomer promote the formation of polymer loops more readily than the two-arm oligomers, which are thought to form less effective "chain entanglements". Furthermore, it is considered important that such polymer loops are more readily formed if the arms of the trifunctional oligomer are sufficiently long, for example, those having the chain lengths specified above.

[0052]

[0054] In a preferred embodiment, the oligomer component has the following structure (I):

Chemical formula

[0053]

[0055] In Structure (I), the junction point of the oligomer is located at a point along the polyether triol P1 where each of the three polyether chains intersects. On the other hand, the chain length represents the sum of the molecular weights of all atoms corresponding to the portion of P1 of each arm and the molecular weights of the I1, P2, I2, and related R n groups.

[0054]

[0056] In an alternative embodiment, the oligomeric component has the following Structure (II):

Chemical formula

[0055]

[0057] In yet a further embodiment, the oligomer component has the following structure (III):

Chemical formula

[0056]

[0058] In yet a further embodiment, the oligomer component has the following structure (IV):

Chemical formula

[0057]

[0059] In certain embodiments, the chain length between the junction point and the outermost end point along at least one, more than one, or each of the arms of the reactive urethane oligomer of any of structures (I)-(IV) is at least 3 kilodaltons (kDa), or at least 4 kDa, or at least 5 kDa, or at least 6 kDa, or at least 7 kDa, or at least 8 kDa, or at least 10 kDa, and at most 60 kDa, or at most 50 kDa, or at most 40 kDa, or at most 35 kDa, or preferably 4 kDa to 35 kDa.

[0058]

[0060] In certain embodiments, the oligomer component comprises, consists of, or consists essentially of a reactive urethane oligomer shown in any of structures (I)-(IV), and the oligomer shown in any of structures (I)-(IV) has a theoretical molecular weight of at least 20 kilodaltons (kDa), or at least 30 kDa, or at least 40 kDa, or 20-100 kDa, or 30-80 kDa, or 35-55 kDa.

[0059]

[0061] According to one embodiment, it is explicitly contemplated that the oligomer component of the composition according to the present invention may have at least one oligomer having a structure corresponding to any of the above structures (I) to (IV). The oligomer component may further have at least one oligomer having more than one structure corresponding to formulas (I) to (IV). For example, by way of example, the oligomer component may have oligomers selected from (I) and (II), (I) and (III), (I) and (IV), (II) and (III), (II) and (IV), (III) and (IV), (I), (II), and (III), (I), (II), and (IV), (II), (III), and (IV), or (I), (III), and (IV). Of course, the oligomer component may further have each of the oligomers having structures corresponding to formulas (I), (II), (III), and (IV).

[0060]

[0062] One or more of the above-described reactive urethane oligomers can be employed in the composition according to the present invention in any suitable amount and can be selected alone or in one or more combinations of the types listed herein. Reactive urethane oligomers described elsewhere in this specification, particularly long-arm trifunctional and tetrafunctional reactive urethane oligomers, tend to have higher viscosity values than those typically used in optical fiber coating applications. Therefore, in order to ensure a composition having a viscosity suitable for a particular optical fiber coating application being employed, the total amount of their use in the entire formulation may need to be limited to an amount that would be understood by one of ordinary skill in the art to which the present invention pertains. Thus, in certain embodiments, the oligomer component or reactive urethane oligomer is present in an amount of less than 65 wt.%, or 10 - 65 wt.%, or 10 - 55 wt.%, or 10 - 50 wt.%, or 10 - 40 wt.%, or 15 - 65 wt.%, or 15 - 55 wt.%, 15 - 50 wt.%, or 15 - 40 wt.%, or 20 - 65 wt.%, or 20 - 55 wt.%, or 20 - 50 wt.%, or 20 - 40 wt.%, or 25 - 65 wt.%, or 25 - 55 wt.%, or 25 - 50 wt.%, or 25 - 40 wt.%, or 30 - 65 wt.%, or 30 - 55 wt.%, or 30 - 50 wt.%, or 30 - 40 wt.% based on the total weight of the composition.

[0061] [Diluent Component]

[0063] The composition according to the first aspect of the present invention also includes a diluent component, i.e., one or more individual diluents of a group having one or more specific structures or types. As used herein, "diluent" means a substance that reduces the viscosity of the larger composition to which it is added or with which it is associated. Various diluents are used to maximize the flowability and thus the processability of the associated optical fiber coating.

[0062]

[0064] To maximize the curability of the related composition, the diluent component preferably comprises, consists of, or consists essentially of a reactive diluent. As specified in connection with the identification of the oligomer component described elsewhere herein, "reactive" means the ability to form a chemical reaction, preferably a polymerization reaction, with other molecules. For this reason, a reactive compound will be said to have at least one reactive group or functional group. Such a reactive group or functional group is preferably a polymerizable group.

[0063]

[0065] More preferably, the diluent component comprises, consists of, or consists essentially of a reactive diluent monomer. A monomer is a low relative molecular mass molecule having a structure capable of contributing to the structural unit of the essential structure of a macromolecule by undergoing polymerization. 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 certain embodiments, 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 800 g / mol or 100 g / mol to 350 g / mol as determined by NMR method.

[0064]

[0066] The diluent component according to the present 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 an average of one polymerizable group. The polymerizable group of the reactive diluent monomer is preferably (co)polymerizable with the polymerizable group present in the related reactive oligomer component.

[0065]

[0067] The polymerizable group of the reactive diluent can be of any known type. However, in certain embodiments, the polymerizable group can include, consist essentially of, or consist of acrylate groups, acrylamide groups, or N-vinylamide groups, or any combination thereof. The reactive diluent is preferably an ethylenically unsaturated polymerizable compound containing at least one reactive olefinic double bond.

[0066]

[0068] The polymerizable group can be present at any feasible location along the length of the reactive diluent. However, in a preferred embodiment, the polymerizable group includes, consists essentially of, or consists of polymerizable end groups.

[0067]

[0069] The diluent component according to the present invention can include any known type of compound or substance that conforms to the definitions specified elsewhere in this specification. However, in a preferred embodiment, the diluent component includes, consists essentially of, or consists of one or more reactive diluent monomers containing one double bond.

[0068]

[0070] 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 nonylphenol acrylate, and diethylene glycol ethylhexyl acrylate (DEGEHA). Further examples of these monomers are acrylonitrile, acrylamide, N-substituted acrylamide, vinyl esters such as vinyl acetate, styrene, alkylstyrene, halostyrene, N-vinylpyrrolidone, 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.

[0069]

[0071] In a preferred embodiment, the diluent component comprises, consists essentially of, or consists of one or more monofunctional diluent monomers. As used herein, "monofunctional" means having an average of 0.5 to 1.4 polymerizable groups per molecule as determined by NMR method. In a preferred embodiment, the diluent component comprises, consists of, or consists essentially of a functional monomer such as a (meth)acrylic monomer.

[0070]

[0072] One or more of the above diluents can be employed in the composition according to the present invention in any suitable amount to adjust the viscosity of the associated formulation to be suitable for an optical fiber coating process used according to methods well known in the art to which the present invention is applied, and can be selected alone or in combination with one or more of the types listed herein. In certain embodiments, the diluent component is present in an amount of 20 wt.% to 85 wt.%, or 30 to 85 wt.%, or 30 to 80 wt.%, or 30 to 75 wt.%, or 30 to 70 wt.%, or 30 to 65 wt.%, or 30 to 60 wt.%, or 30 to 50 wt.%, 35 to 85 wt.%, or 35 to 75 wt.%, or 35 to 65 wt.%, or 35 to 55 wt.%, or 40 to 85 wt.%, or 40 to 75 wt.%, or 40 to 65 wt.%, or 40 to 55 wt.%, or 50 to 85 wt.%, or 50 to 75 wt.%, or 50 to 65 wt.% based on the total weight of the radiation curable composition.

[0071] [Photoinitiator component]

[0073] According to a first aspect, the radiation curable composition comprises a photoinitiator component, i.e., one or more individual photoinitiators of a group having one or more specific structures or types. A photoinitiator is a compound that undergoes a chemical change upon the action of light or by the synergistic effect of the action of light and the electronic excitation of a sensitizing dye to produce 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 an embodiment of the present invention, the photoinitiator is a free radical photoinitiator.

[0072]

[0074] 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. Patent Nos. 4,324,744; 4,737,593; 5,942,290; 5,534,559; 6,020,529; 6,486,228; and 6,486,226. Preferred types of acylphosphine oxide photoinitiators for use in the photoinitiator component include bisacylphosphine oxide (BAPO) or monoacylphosphine oxide (MAPO). More specifically, by way of example, 2,4,6-trimethylbenzoyl ethoxyphenylphosphine oxide (CAS#84434-11-7), or 2,4,6-trimethylbenzoyl diphenylphosphine oxide (CAS#127090-72-6) may be mentioned.

[0073]

[0075] The photoinitiator component may also optionally include, consist of, or consist essentially of an α-hydroxyketone photoinitiator. For example, suitable α-hydroxyketone photoinitiators are α-hydroxycyclohexyl phenyl 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-methylpropionyl)-benzyl]phenyl}-2-methylpropane-1-one, and 2-hydroxy-2-methyl-1-[(2-hydroxyethoxy)phenyl]propanone.

[0074]

[0076] In another embodiment, the photoinitiator component includes, consists of, or consists essentially 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’ - phenylbenzophenone, or 3 - methyl - 4’ - phenylbenzophenone; ketal compounds such as 2,2 - dimethoxy - 1,2 - diphenyl - ethanone; and monomeric or dimeric phenylglyoxylate esters such as methyl phenylglyoxylate, 5,5’ - oxo - bis(ethylenedioxycarbonylphenyl), or 1,2 - (benzoylcarboxy)ethane).

[0075]

[0077] Further suitable photoinitiators for use in the photoinitiator component include oxime esters such as those disclosed in U.S. Patent No. 6,596,445. Another class of suitable photoinitiators for use in the photoinitiator component includes, for example, phenylglyoxalates such as those disclosed in U.S. Patent No. 6,048,660.

[0076]

[0078] In another embodiment, the photoinitiator component may comprise, consist of, or consist essentially of one or more alkyl-substituted, aryl-substituted, or acyl-substituted compounds not listed above herein.

[0077]

[0079] According to another embodiment, the composition may contain a photoinitiator of an alkyl-substituted, aryl-substituted, or acyl-substituted compound. In certain embodiments, the alkyl-substituted, aryl-substituted, or acyl-substituted photoinitiator has or is centered on an atom of Group 14 (carbon group) of the Periodic Table. In such instances, upon excitation (via absorption of radiation), the Group 14 atom present in the photoinitiator compound forms a radical. Thus, such compounds generate radicals having or centered on an atom selected from the group consisting of silicon, germanium, tin, and lead. In certain embodiments, the alkyl-substituted, aryl-substituted, or acyl-substituted photoinitiator is an acylgermanium compound. Such photoinitiators are described in U.S. Patent No. 9,708,442, issued to DSM IP Assets B.V., the entire disclosure of which is incorporated herein by reference. Known specific acylgermanium photoinitiators include benzoyltrimethylgermanium (BTG), tetraacylgermanium, or bisacylgermanoyl (commercially available as Ivocerin® from Ivoclar Vivadent AG, 9494 Schaan / Liechtenstein).

[0078]

[0080] The photoinitiators according to the present invention can be employed singly or in one or more combinations as a blend. Suitable photoinitiator blends are disclosed, for example, in U.S. Patent No. 6,020,528 and U.S. Patent Application No. 60 / 498,848. According to certain embodiments, the photoinitiator component comprises, for example, a photoinitiator blend of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide (CAS#162881-26-7) and 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide (CAS#84434-11-7) in a weight ratio of about 1:11, 1:10, 1:9, 1:8, or 1:7.

[0079]

[0081] Other particularly suitable photoinitiator blends are, for example, mixtures of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, 2,4,6-trimethylbenzoylethoxyphenylphosphine oxide, and 2-hydroxy-2-methyl-1-phenyl-1-propanone (CAS#7473-98-5) in a weight ratio of about 3:1:15, 3:1:16, 4:1:15, or 4:1:16). Other suitable photoinitiator blends are, for example, mixtures of bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide and 2-hydroxy-2-methyl-1-phenyl-1-propanone in a weight ratio of about 1:3, 1:4, or 1:5.

[0080]

[0082] One or more of the above-described photoinitiators can be employed in any suitable amount for use as the photoinitiator component of the composition according to the first aspect of the present invention and can be selected singly or in combination with 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 certain embodiments, the photoinitiator component is present in an amount of about 0.1 wt.% to about 10 wt.%, or about 0.1 wt.% to about 5 wt.%, or about 1 wt.% to about 5 wt.% based on the total weight of the composition.

[0081] [Additive]

[0083] The radiation curable composition according to the present invention optionally contains an additive component, i.e., one or more individual additives of a group having one or more specific structures or types. Typically, additives are also added to the optical fiber coating in order to achieve certain specific desirable properties, such as improved adhesion to glass optical fibers, improved shelf life, improved oxidation stability and hydrolysis stability of the coating. There are many different types of desirable additives, and although the present invention discussed herein is not intended to be limited thereby, they have desirable effects and are included in the envisioned embodiments.

[0082]

[0084] Examples of additives for use in the additive component include heat suppressants intended to prevent premature polymerization, such as hydroquinone, hydroquinone derivatives, p-methoxyphenol, beta-naphthol, or sterically hindered phenols such as 2,6-di(tert-butyl)-p-cresol. The dark storage life can be increased by using, for example, copper compounds such as copper naphthenate, copper stearate, or copper octoate, phosphorus compounds such as triphenylphosphine, tributylphosphine, triethyl phosphite, triphenyl phosphite, or tribenzyl phosphite, or quaternary ammonium compounds such as tetramethylammonium chloride or benzyltrimethylammonium chloride.

[0083]

[0085] Additives such as paraffin or similar waxy substances can be added to expel atmospheric oxygen during polymerization. Since these have low solubility in the polymer, they migrate to the surface when polymerization begins and form a transparent surface layer that prevents the entry of air. Similarly, it is possible to apply an oxygen barrier layer.

[0084]

[0086] Further potentially suitable additives include light stabilizers. Examples of light stabilizers include UV absorbers, such as well-known commercially available UV absorbers of the hydroxyphenylbenzotriazole type, hydroxyphenyl-benzophenone type, oxamide type, or hydroxyphenyl-s-triazine type. It is possible to use such individual compounds or mixtures thereof, with or without the concomitant use of a sterically hindered relatively non-basic amine light stabilizer (HALS). The sterically hindered amine is based, for example, on 2,2,6,6-tetramethylpiperidine. Examples of UV absorbers and sterically hindered amines include the following.

[0085]

[0087] 2-(2-Hydroxyphenyl)-2H-benzotriazoles, such as known commercially available hydroxyphenyl-2H-benzotriazoles, and those disclosed in U.S. Patent 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, 4,347,180, 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-hydroxyocta-(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)-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-octyl-(6-2H-benzotriazol-2-yl)phenol), 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.,

[0086]

[0088] As another class of examples, 2-hydroxybenzophenones such as derivatives of 4-hydroxy, 4-methoxy, 4-octyloxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2’,4’-trihydroxy, and 2’-hydroxy-4,4’-dimethoxy can be mentioned.

[0087]

[0089] As yet another class of examples, there may be mentioned esters of substituted and unsubstituted benzoic acids, for example, 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoyl resorcinol, bis(4-tert-butylbenzoyl) resorcinol, benzoyl resorcinol, 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.

[0088]

[0090] Additional additives suitable for use as additive components include compounds that promote photopolymerization, for example, so-called photosensitizers that shift or broaden the spectral sensitivity of the composition being incorporated. Specific examples of photosensitizers include aromatic carbonyl compounds such as benzophenone derivatives, thioxanthone derivatives, anthraquinone derivatives, and 3-acylcoumarin derivatives, further including 3-(aroylmethylene)thiazolines, further including eosin dyes, rhodamine dyes, and erythrosine dyes. Alternatively, non-aromatic carbonyl compounds may be used. An example of a non-aromatic carbonyl is dimethoxyanthracene.

[0089]

[0091] The curing procedure can be assisted, specifically, by using additives that produce or facilitate the production of a pigmented composition. Such additives include pigments such as titanium dioxide as described in U.S. Patent No. 4,753,817, as well as additives that form free radicals under thermal conditions, for example, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), triazene, diazosulfide, pentaazadiene, or peroxy compounds such as hydroperoxides or peroxyesters, for example, t-butyl hydroperoxide. Further suitable substances for this purpose include benzopinacol compounds.

[0090]

[0092] As the additive component, a photoreductive dye such as a xanthene dye, a benzoxanthene dye, a benzothioxanthene dye, a thiazine dye, a pyronin dye, a porphyrin dye, an acridine dye, and / or a trihalomethyl compound cleavable by radiation can be mentioned. Such additives are described, for example, in U.S. Patent No. 5,229,253.

[0091]

[0093] Depending on the intended use, other conventional additives can be used. Examples include optical brighteners, fillers, pigments, dyes, wetting agents, or leveling aids. Also, as described in, for example, U.S. Patent No. 5,013,768, a thick coating with added pigment can contain glass microbeads or powdered glass fibers.

[0092]

[0094] In certain embodiments, the additive component includes one or more various additives used to improve one or more properties of the primary coating. Such additives include antioxidants (e.g., Irganox 1035, thiodiethylene bis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], or tert-butylhydroquinone), adhesion promoters, inhibitors (e.g., acrylic acid), photosensitizers, carrier surfactants, tackifiers, catalysts, stabilizers, surface agents, and optical brighteners.

[0093]

[0095] 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 linkage between the polymer primary coating and the surface of the optical glass fiber. Hydrolyzable silane coupling agents have been used as glass adhesion promoters. Silane coupling agents are described in particular in U.S. Patent No. 4,932,750. In certain embodiments, the adhesion promoter is a hydrolyzable silane compound containing a mercapto group and / or plural alkoxy groups. Such adhesion promoters are known and are described in U.S. Patent Application Publication No. 20020013383 (the relevant portions of which are incorporated herein by reference).

[0094]

[0096] In certain embodiments, examples of the adhesion promoter include one or more of gamma-mercaptopropyltrimethoxysilane, trimethoxysilylpropyl acrylate, or 3-trimethoxysilylpropane-1-thiol. The silane coupling group can alternatively react on the oligomer in the oligomer component, and in such a case, it is regarded as part of the oligomer component rather than as an additive.

[0095]

[0097] One or more of the above-described additives can be employed in any suitable amount in the composition according to the present invention and can be selected alone or in combination with one or more of the types listed herein. In a preferred embodiment, the additive component is present in an amount of about 0 wt.% to 40 wt.%, or 0 wt.% to 30 wt.%, or 0 wt.% to 20 wt.%, or 0 wt.% to 10 wt.%, or 0 wt.% to 5 wt.%, or 0.01 wt.% to 40 wt.%, or 0.01 wt.% to 30 wt.%, or 0.01 wt.% to 20 wt.%, or 0.01 wt.% to 10 wt.%, or 0.01 wt.% to 5 wt.%, or 0.1 wt.% to 2 wt.%, based on the total weight of the composition. According to another embodiment, the additive component is present in an amount of 1 wt.% to 40 wt.%, or 1 wt.% to 30 wt.%, or 1 wt.% to 20 wt.%, or 1 wt.% to 10 wt.%, or 1 wt.% to 5 wt.%, based on the weight of the total radiation curable composition.

[0096]

[0098] As described, the compositions formulated according to the various embodiments of the first aspect of the present invention can have excellent properties. Specifically, such compositions have the ability to form a cured coating having a low elastic modulus and / or high tear strength. Thus, in certain embodiments, the compositions according to the first aspect of the present invention have a low elastic modulus of less than 1.5 megapascals (MPa), or less than 1.0 MPa, or less than 0.5 MPa, or less than 0.4 MPa, or less than 0.3 MPa, or from 0.15 to 1.0 MPa, or from 0.2 to 1.0 MPa, or from 0.25 to 0.75 MPa, or from 0.25 to 0.5 MPa, or from 0.25 to 0.8 MPa, or from 0.6 to 0.8 MPa, as measured by the segment elastic modulus (E) of the cured film formed from the composition.

[0097]

[0099] In certain embodiments, the composition has a strain energy release rate G0 value of at least 5 J / m, or at least 9 J / m, or at least 10 J / m, or at least 15 J / m, or at least 25 J / m, or more than 28 J / m, or more than 30 J / m, or more than 33 J / m, or at least 35 J / m, or at least 40 J / m, or from 5 to 50 J / m, or from 5 to 40 J / m, or from 5 to 35 J / m, or from 5 to 25 J / m, or from 5 to 15 J / m, or from 5 to 10 J / m, or from 5 to 9 J / m, or from 9 to 40 J / m, or from 9 to 35 J / m, or from 9 to 25 J / m, or from 9 to 15 J / m, as measured by the strain energy release rate G0 value of the film made from the composition when measured in accordance with ISO 816 (2nd edition dated 1983 - 12 - 01). 2 、 or at least 9 J / m 2 、 or at least 10 J / m 2 、 or at least 15 J / m 2 、 or at least 25 J / m 2 、 or more than 28 J / m 2 、 or more than 30 J / m 2 、 or more than 33 J / m 2 、 or at least 35 J / m 2 、 or at least 40 J / m 2 、 or from 5 to 50 J / m 2 、 or from 5 to 40 J / m 2 、 or from 5 to 35 J / m 2 、 or from 5 to 25 J / m 2 、 or from 5 to 15 J / m 2 、 or from 5 to 10 J / m 2 、 or from 5 to 9 J / m 2 、 or from 9 to 40 J / m 2 、 or from 9 to 35 J / m 2 、 or from 9 to 25 J / m 2 、 or from 9 to 15 J / m 2、 or 10 to 40 J / m 2 、 or 10 to 25 J / m 2 、 or 10 to 15 J / m 2 、 or 25 to 40 J / m 2 has a high tear strength.

[0098]

[0100] In a preferred embodiment, the composition has both a low elastic modulus and a high tear strength. This can be quantitatively determined as the ratio of the strain energy release rate (G0) value (in J / m 2 units) divided by the segment elastic modulus (E) value (in MPa) of the film formed from the radiation curable composition. In certain embodiments, the composition has such a ratio greater than 20, or greater than 25, or greater than 30, or greater than 35, or greater than 50, or greater than 60, or greater than 70, or greater than 75 or greater than 81, or greater than 90, or greater than 100, or greater than 150, or greater than 170, or from 20 to 70, or from 20 to 60, or from 20 to 50, or from 20 to 35, or from 20 to 30, or from 20 to 25, or from 25 to 70, or from 25 to 60, or from 25 to 50, or from 25 to 35, or from 25 to 30, or from 30 to 70, or from 30 to 60, or from 30 to 50, or from 30 to 35, or from 70 to 250, or from 75 to 250, or from 82 to 250, or from 82 to 200, or from 90 to 250, or from 90 to 200 when expressed as G0 / E in units of J / (m 2 ·MPa).

[0099]

[0101] A second aspect of the present invention preferably provides a glass optical fiber by drawing the glass optical fiber through a drawing tower, applying a primary coating composition onto the surface of the glass optical fiber, optionally applying an amount of UV light irradiation sufficient to at least partially cure the primary coating composition, applying a secondary coating composition to the primary coating composition, and exposing the primary coating composition and the secondary coating composition to at least one radiation source capable of emitting ultraviolet rays to cause curing of the primary coating composition and the secondary coating composition, thereby forming a cured primary coating on the surface of the optical fiber and a cured secondary coating on the surface of the cured primary coating. A method for coating an optical fiber, wherein the primary coating composition is a composition according to any of the embodiments of the first aspect of the present invention.

[0100]

[0102] A third aspect of the present invention is a coated optical fiber, wherein the optical fiber to be coated includes a glass core, a cladding layer in contact with and surrounding the glass core, and a coating portion. The coating portion further includes 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 third aspect, the primary coating layer is a cured product of a radiation-curable composition according to any of the embodiments of the first aspect, and the primary and secondary coatings are applied and cured according to any of the embodiments of the second aspect.

[0101]

[0103] According to an embodiment of the third aspect, the optical fiber includes a core, a cladding, a primary coating that contacts and surrounds the outer annular cladding region, and a secondary coating. According to some embodiments, the core includes silica glass having one or more dopants that increase the refractive index of the glass core compared to pure silica glass (SiO2) or pure undoped silica glass. Suitable dopants for increasing the refractive index of the core include, but are not limited to, GeO2, Al2O3, P2O5, TiO2, ZrO2, Nb2O5, Ta2O5, and / or combinations thereof.

[0102]

[0104] The cladding layer has a maximum relative refractive index of the core [Δ 1MAX , as long as it is greater than the maximum relative refractive index of the cladding [Δ 4MAX , it may include pure silica glass (SiO2), silica glass having one or more dopants that increase the refractive index (such as GeO2, Al2O3, P2O5, TiO2, ZrO2, Nb2O5, and / or Ta2O5) in cases where the cladding is "up-doped", or silica glass having a dopant that decreases the refractive index such as fluorine in cases where the inner cladding is "down-doped". According to one embodiment, the cladding is also pure silica glass.

[0103]

[0105] According to some embodiments of the third 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 from 0.15 to 0.8 MPa, or from 0.15 to 0.8 MPa, or less than 0.2 MPa in other embodiments. Methods of describing the in-situ modulus are well known in the art and are described, in particular, in U.S. Patent No. 7,171,103 and U.S. Patent No. 6,961,508, each assigned to DSM IP Assets B.V. In certain embodiments, 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, or -50°C or less in other embodiments. A primary coating having a low in-situ modulus reduces microbending, which is a coupling mechanism between the modes propagating within 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 placed in an extremely cold environment. In a preferred embodiment, the primary coating according to the third aspect also has a high tear strength value, for example, at least 5 J / m 2 or at least 9 J / m 2 or at least 10 J / m 2 or at least 15 J / m 2 or at least 25 J / m 2 or 28 J / m 2 or more than 30 J / m 2 or more than 33 J / m 2 or more than 35 J / m 2 or at least 40 J / m 2 or from 5 to 50 J / m 2 or from 5 to 40 J / m 2 or from 5 to 35 J / m 2 or from 5 to 25 J / m 2 or from 5 to 15 J / m 2 or from 5 to 10 J / m 2 or from 5 to 9 J / m 2 or from 9 to 40 J / m 2 or from 9 to 35 J / m 2 or from 9 to 25 J / m2 or 9 - 15 J / m 2 or 10 - 40 J / m 2 or 10 - 25 J / m 2 or 10 - 15 J / m 2 or 25 - 40 J / m 2 has a tearing strength G0 of. Also, since it is beneficial for the coated optical fiber to maintain both a low elastic modulus and a high tearing strength, in a preferred embodiment, the coated optical fiber according to the third aspect has the following ratio of tearing strength to in - situ elastic modulus (in units of J / (m 2 ·MPa)).

[0104]

[0106] Greater than 30, or greater than 60, or greater than 70, or 75 or more or greater than 81, or greater than 90, or greater than 100, or greater than 150, or greater than 170, or greater than 200, or 70 - 300, or 75 - 300, or 82 - 300, or 82 - 200, 90 - 250, or 90 - 200.

[0105]

[0107] The primary coating maintains proper adhesion to the glass fiber during heat aging and hydrolysis aging and can be peeled therefrom (if required) for splicing purposes. The primary coating typically has a thickness in the range of 20 - 50 μm (for example, about 25 or 32.5 μm), and for a 200 μm fiber, a thinner thickness in the range of 15 - 25 μm. In other embodiments, the primary coating preferably has a thickness of less than about 40 μm, more preferably about 20 - about 40 μm, and most preferably about 20 - about 30 μm.

[0106]

[0108] The secondary coating contacts and surrounds the primary coating. The secondary coating is, for example, a polymerization product of a coating composition in which molecules become in a cross - linked state during polymerization. The secondary coating according to certain embodiments can have an in - situ tensile elastic modulus greater than 800 MPa, or greater than 1110 MPa, or greater than 1300 MPa, or greater than 1400 MPa, or greater than 1500 MPa. The secondary coating having a high in - situ elastic modulus reduces micro - bending, which is a coupling mechanism between modes propagating within the fiber.

[0107]

[0109] According to other embodiments, the secondary coating has a high in-situ elastic modulus (e.g., greater than about 800 MPa at 25° C.) and a high T g (e.g., greater than about 50° C.). In other preferred embodiments, 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. The in-situ T g of the secondary coating 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.

[0108]

[0110] Suitable materials for use as the outer (or secondary) coating material, and requirements regarding the selection of such materials, are well known in the art and are described, for example, in U.S. Pat. Nos. 4,962,992 and 5,104,433, both issued to Chapin. Alternatively, as described in U.S. Pat. No. 6,775,451 issued to Botelho et al. and U.S. Pat. No. 6,689,463 issued to Chou et al., high elastic modulus coatings have been obtained using coating systems with low oligomer contents. Additionally, as described in U.S. Patent Application Publication No. 20070100039 issued to Schissel et al., non-reactive oligomer components have been used to achieve high elastic modulus coatings. As is well known in the art, the secondary coating may also include ink. In such cases, the secondary coating is referred to as a "colored secondary coating."

[0109]

[0111] The coated optical fiber may alternatively include one or more additional layers disposed on the secondary layer. Most notably, such layers include a stand-alone "ink" layer applied and cured separately from the secondary coating. Other multilayer coating systems are known, for example, as disclosed in WO 2017 / 173296 pamphlet.

[0110]

[0112] For curing using a broadband UV lamp, how to formulate typical optical fiber coatings for the primary and secondary coatings for the fiber described above, as well as for inks and matrix materials, is known in the art. A good consideration of such techniques and related chemistry and test methods can be found in Chapter 4, Section 4.6 to the end of the book "Specialty Optical Fibers Handbook" published by Elsevier, written by A. Mendez and T.F. Morse, (Copyright) Elsevier, 2007.

[0111]

[0113] Any type of optical fiber can be used in the embodiments of the third aspect of the present invention. However, in a preferred embodiment, the coated optical fiber has a mode field diameter of 8 to 10 μm at a wavelength of 1310 nm or 9 to 13 μm at a wavelength of 1550 nm and / or an effective area of 20 to 200 μm 2 . Such fibers can be single-mode and / or large effective area fibers considering the expected demand for fiber coating processes that utilize higher line speeds or processing speeds. However, other fiber types such as multimode fibers can also be used similarly.

[0112]

[0114] A fourth aspect of the present invention is an optical fiber cable, wherein the optical fiber includes at least one optical fiber according to the third aspect of the present invention, and / or the optical fiber is a cured product of the composition according to the first aspect of the present invention, and / or the optical fiber is coated according to the second aspect of the present invention.

[0113]

[0115] The improved compositions of the present invention (and the coated optical fibers manufactured therefrom) can be formulated by selecting the components specified above in this specification. Further, those skilled in the art to which the present invention pertains can easily adjust them according to the formulation guidelines in this specification and, furthermore, by extrapolating from the general methods employed in the embodiments illustrated in the following examples. The following such examples further illustrate the present invention, but of course, should not be construed as limiting its scope in any way.

[0114] [Examples]

[0116] These examples illustrate embodiments of the present invention. Table 1 describes the various components of the compositions used in this example. Table 2 describes various further aspects of the oligomers prepared from the reagents in Table 1, and the synthesis thereof is further described below. Table 3 shows the test results of all formulations prepared from the components described in Table 1 and the oligomers characterized in Table 2.

[0115]

Table 1

[0116] [Synthesis of Oligomers]

[0117] The oligomers used in this specification were prepared in TDA as a reactive diluent (which itself was used at 25% by weight) by methods well known in the art to which the present invention pertains. After charging the diisocyanate, catalyst (DBTDL), and stabilizers (BHT and acrylic acid) into the reactor, the hydroxy-functional compound was added following the completion of the previous urethane formation.

[0117]

[0118] Oligomer 1: For the HEA-functionalized triol oligomer 1, 6 mol eq. of diisocyanate (Desmodur T-100), 3 mol eq. of monohydroxy-functional compound (HEA), 3 mol eq. of dihydroxy-functional compound (diol) Acrylim 8200, and 1 mol eq. of trihydroxy-functional compound (triol) Acrylim 6320N(C) were used. The "ideal" structure is, P6000(triol)-(T-P8000-T-H)3 wherein, "P6000(triol)" represents the reaction product of polyol Acrylim 6320N (through which the junction points of the oligomer are located), "T" represents the reaction product of the diisocyanate compound TDI, "H" represents the reaction product of the acrylate compound HEA having a polymerizable acrylate group, and "P8000" represents the reaction product of Acrylim 8200 polyol. The suffix 3 on "(T-P8000-T-H)" indicates that the oligomer has three distinguishable arms branching from the junction points along the triol core. As shown, this oligomer has three polymerizable acrylate end groups. Further characterization of this oligomer is shown in Table 2. The SEC plot of oligomer 1 obtained by the experimental method described elsewhere in the present specification below is depicted in FIG. 1.

[0118]

[0119] Oligomer 2: For the HEMA-functionalized triol oligomer 2, 6 mol eq. of diisocyanate (Desmodur T-100), 3 mol eq. of monohydroxy-functional compound (HEMA), 3 mol eq. of dihydroxy-functional compound (diol) Acrylim 8200, and 1 mol eq. of trihydroxy-functional compound (triol) Acrylim 6320N(C) were used. The "ideal" structure is, P6000(triol)-(T-P8000-T-HM)3 It is as follows. In the formula, "P6000 (triol)" represents the reaction product of polyol acrylmere 6320N (through which the junction point of the oligomer is located), "T" represents the reaction product of diisocyanate compound TDI, "HM" represents the reaction product of methacrylate compound HEMA having a polymerizable methacrylate group, and "P8000" represents the reaction product of acrylmere 8200 polyol. The suffix 3 on "(T-P8000-T-H)" indicates that the oligomer has three distinguishable arms branching from the junction point along the triol core. As can be seen, this oligomer has three polymerizable methacrylate end groups. Further characterization of this oligomer is shown in Table 2.

[0119]

[0120] Oligomer 3: For the lower molecular weight linear HEA-functionalized diol oligomer 3, 3 mol eq. of diisocyanate (Desmodur T-100), 2 mol eq. of monohydroxy-functional compound (HEA), and 2 mol eq. of bis-hydroxy-functional compound (diol) acrylmere 8200 were used. The "ideal" structure is H-(T-P8000)2-T-H It is as follows. In the formula, "P8000", "T", and "H" are defined herein in relation to the above oligomers 1 and 2. The suffix 2 on "(T-P8000)" indicates that the oligomer has two distinguishable linear blocks containing the reaction product of P8000 diol. As can be seen, this oligomer is linear with two arms originating from the core and has two polymerizable acrylate end groups. Further characterization of this oligomer is shown in Table 2. The SEC plot of oligomer 3 obtained by the experimental method described elsewhere in the following specification is depicted in Figure 2.

[0120]

[0121] Oligomer 4: For the higher molecular weight linear HEA-functionalized diol oligomer 4, 5 mol eq. of diisocyanate (Desmodur T-100), 2 mol eq. of monohydroxy-functional compound (HEA), and 4 mol eq. of bis-hydroxy-functional compound (diol) acrylmere 8200 were used. The "ideal" structure is H-(T-P8000)4-T-H wherein, "P8000", "T", and "H" are as defined in the above description related to oligomers 1 and 2. The suffix 4 on "(T-P8000)" represents that the oligomer has four distinguishable linear blocks containing the reaction product of P8000 diol. As can be seen, this oligomer is linear with two arms originating from the core and has two polymerizable acrylate end groups. Further characterization of this oligomer is shown in Table 2. The SEC plot of oligomer 4 obtained by the experimental methods described elsewhere in the following specification is depicted in Figure 3.

[0121] [Characterization of Oligomers]

[0122] Each of the oligomers synthesized above was further characterized by several parameters evaluated in the experiments listed below. For each oligomer, the ideal structure, particularly, the functionality, the number of arms, the chain length between the junction point and the farthest end point, and the total theoretical oligomer molecular weight were determined with respect to the relevant ideal structure. The functionality represents the number of (meth)acrylic groups on the oligomer, and the number of arms will be apparent to those skilled in the art related to the present invention by referring to the ideal structure. The chain length of the longest arm (the theoretical value shown in Table 2 as "theoretical chain length of the longest arm") was determined by adding the atomic weights of all the reactants used in the preparation of a specific arm from the junction point to the farthest end point in the ideal oligomer structure. In the case of an oligomer end-capped with an -OH group instead of an HEA group (by a reactant such as 2-ethylhexanol) (not shown), for example, since the molecular weight of 2-ethylhexanol (130.23 g / mol) is larger than that of HEA (116.12 g / mol), typically, this arm will be represented as the longest arm. The total theoretical oligomer molecular weight (described as "Mn,theo" in Table 2) was determined by taking the sum of the atomic weights of all the atoms in the ideal structure of each oligomer. The chain length and Mn,theo are reported in kilodaltons (kDa) rounded to the specified 0.1 kDa or 0.01 kDa place.

[0122]

[0123] Next, to determine the number average molecular weight (Mn), weight average molecular weight (Mw), and z average molecular weight (Mz) of the oligomers produced, each of the oligomers described above produced herein was analyzed via SEC by the methods described in the following section. Details regarding each of these parameters can be found in Polymer Molecular Weight Distribution and Definitions of MW Averages, Agilent Technologies, April 30, 2015, 5990-7890EN (https: / / www.agilent.com / cs / library / technicaloverviews / Public / 5990-7890EN.pdf). Finally, other values were derived therefrom, including the measured chain length of the longest arm (described in Table 2 as the "experimental chain length longest arm") and the ratio of the measured Mz to Mn values. When all arms of the oligomers had a theoretical equivalent structure in all examples of Table 2, the "experimental chain length longest arm" was determined by dividing Mn by the number of arms. Values for the parameters considered herein are all reported in Table 2 as required.

[0123] [Characterization by SEC]

[0124] Next, using the synthesized various reactive oligomers, the size exclusion chromatography (SEC) method was evaluated in accordance with ASTM: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). In addition, ASTM standard D5226-98: "Standard Practice for Dissolving Polymer Materials", ASTM International, West Conshohocken, PA, (2010) was used to facilitate the definition of solvents suitable for polymer analysis.

[0124]

[0125] Specifically, all size exclusion chromatography measurements were performed using a Waters APC (Advanced Polymer Chromatography) system equipped with an RI detector, a Wyatt microDawn multi-angle light scattering device, and a Wyatt microViscoStar capillary-bridge differential viscometer. For chromatographic separation, columns: 4.6×76 mm, Acquity APC XT450 2.5 μm, 125 2.5 μm, 45 1.7 μm 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 a concentration in the range of 1.0 to 1.5 mg / ml. This THF solution was also used as the eluent at a flow rate of 0.5 ml / min in SEC analysis.

[0125]

[0126] Once dissolution was complete, the molar mass and molar mass distribution were then determined by the triple detection method referenced above using refractive index, differential viscosity, and right angle light scattering signals. For the calculation of the molecular weight average and molar mass distribution, a refractive index increment (dn / dc) of approximately 0.07 ml / g was used. Specifically, the dn / dc values for oligomers 1-4 were determined to be 0.0695, 0.0708, 0.0780, and 0.0792, respectively. The refractive index increment and molecular weight average as well as the molar mass distribution were determined by integration over the entire refractive index chromatogram. The integration limits were set using the IV-DP signal. The recovery rate of the sample from the column varied from 95 to 105%. This is typical of values obtained by size exclusion chromatography.

[0126]

[0127] Using the method defined above, the values of Mn, Mw, and Mz were recorded and reported.

[0127]

Table 2

[0128] [Formulations 1-10]

[0128] Using one or more of the oligomers described above and characterized in Table 2, each of the formulations described in Table 3 below was prepared by mixing 100 g of the sample in a 100 ml mixing cup suitable for use with a SpeedMixer (trademark). Specifically, a photoinitiator was added to the amounts of oligomers specified in Table 3 below, followed by the addition of a specified amount of monomer to make a total of 100 g. Then, the mixture was pre-mixed by hand to ensure good mixing and introduction of the oligomers into the monomers used. The cup was then closed and mixed vigorously in a SpeedMixer (trademark) DAC150FVZ at 3500 rpm for 3 minutes. After that, it was stopped and heated to 55 °C in an oven to ensure complete dissolution of all components and maintained at this temperature for about 1 hour. Finally, the sample was removed from the oven and remixed in the SpeedMixer again for 30 seconds by the same method.

[0129]

[0129] These formulations were tested according to the methods described below to determine the initial viscosity, segment elastic modulus (E), tear strength (G0), and G0 / E ratio for each sample. Viscosity values were rounded to the nearest 0.01 Pascal-second, while segment elastic modulus values were rounded to the second or third decimal place and presented herein. Finally, the G0 value was calculated and rounded to the first decimal place and presented herein. The values of these measured properties are reported in Table 3 below.

[0130] [Viscosity]

[0130] Viscosity was measured using an Anton Paar Rheolab QC. The instrument was configured to match the previously used Z3 system. For each measurement, an amount of 14.7 ± 0.2 g of sample was loaded into a disposable aluminum cup. If the sample in the cup was inspected and determined by visual inspection to contain bubbles, both the sample and the cup were subjected to centrifugation or allowed to stand for a sufficient time for the bubbles to escape from most of the liquid. Bubbles appearing on the top surface of the liquid were considered acceptable.

[0131]

[0131] Next, the bob was gently loaded into the liquid in the measuring cup, and then the cup and bob were placed inside the instrument. The sample temperature was equilibrated with the temperature of the circulating liquid (which itself was maintained at 25 degrees Celsius) by waiting for 5 minutes. Then, the rotational speed was set to a specific value to generate a desired shear rate of 50 sec -1 of.

[0132]

[0132] Subsequently, the measurement readings were obtained. When the apparatus panel presented a viscosity value and the viscosity value varied very slightly over 15 seconds (relative variation less than 2%), the measurement was aborted. When a relative variation exceeding 2% was observed, the sample was further equilibrated for 5 minutes and then the test was resumed. If sample variation remained after the additional equilibration time, the shear rate was corrected according to methods well known in the art to which the present invention pertains in order to more accurately grasp the viscosity of the sample. The reported results were represented by the average viscosity values of three individual test samples. Unless otherwise specified, values were expressed and recorded in units of Pascal seconds (Pa·s). The results of each example are reported in Table 3 below.

[0133] [Preparation of all film samples for measurement]

[0133] Samples were cured with a UV dose of 1 J / cm of a conveyor fusion unit model DRS-10 / 12QN, UV lamp system having a 1600M radiator equipped with an R500 reflector (D bulb with a power of 600 W / inch equal to 240 W / cm) as the lamp. Subsequently, the UV dose was measured using an International Light 390 radiometer. The UV peak dose measured under the condition of 1 J / cm 2 was 8.1 W / cm 2 The conditions measured were 2 as follows.

[0134] [Test methods for tensile strength, elongation, and modulus of elasticity]

[0134] The method for determining the segment modulus of elasticity used herein is found in European Patent No. 2089333 B1 granted to DSM IP Assets B.V., the entire content of which is incorporated herein by reference. The tensile properties (tensile strength, percent elongation at break, and modulus of elasticity) of the cured sample were determined using an MTS Criterion (trademark) model 43.104. Samples were prepared for testing by curing a 150 μm film of the material using a Fusion UV processor. The samples were cured in a nitrogen atmosphere at 1.0 J / cm 2It is cured. Test specimens having a width of 1.27 cm (0.5 inches) and a length of 12.7 cm (5 inches) are cut from the film. The exact thickness of each specimen is measured with a micrometer.

[0135]

[0135] Since these are relatively soft coatings (e.g., those having a modulus of elasticity of less than about 10 MPa), the coating is drawn down on a glass plate and cured, and individual specimens are cut from the glass plate with a scalpel. A 0.9 kg (2 lb) load cell is used with an Instron to calculate the modulus of elasticity at 2.5% elongation by least squares fitting of the stress-strain plot. The cured film is conditioned at 23.0 ± 0.1 °C and 50.0 ± 0.5% relative humidity for at least 16 - 24 hours prior to testing.

[0136]

[0136] In the testing of specimens, the gauge length is 5.1 cm (2 inches) and the crosshead speed is 2.54 cm / min (1 inch / min). All tests are conducted at a temperature of 23.0 ± 0.1 °C and a relative humidity of 50.0 ± 0.5%. All measurements are determined from the average of at least six test specimens.

[0137]

[0137] The values of the segment modulus of elasticity (E) are recorded for each example and reported in Table 3 below.

[0138] [Measurement of Strain Energy Release Rate or Tear Strength (G0)]

[0138] The distortion energy release rate G0 was measured in accordance with the international standard ISO 816 (Second Edition 1983-12-01), "Vulcanized Rubber - Determination of Tear Strength of Small Specimens (Delft Specimens)". The test specimens used were prepared in accordance with ISO 816. The length between the grips was 20 mm. The thickness (d) was 0.15 mm (6 mils) and was measured with a Mitutoyo micrometer having a resolution of 0.001 mm. The cured samples were cut using an ASTM D1822 type L die manufactured by MS Instrument Company Inc., the slit length (b) was 4.70 mm of the initial crack, and the fixed sample width was 9.1 mm and the length was 60 mm.

[0139]

[0139] Regarding the equipment used, the test was conducted with an RSA-G2 machine manufactured by TA instruments. The force sensor used was an FRT transducer adapted to a maximum force of 3500 grams (34.32 N) connected to a linear air bearing motor having a frequency up to 100 Hz and an amplitude of ±1.5 mm. The elongation was measured with a clamp at a speed of approximately 0.01 mm / s obtaining data points every second. The test speed was a Hencky strain rate of 4.5e -4 / s. The test was conducted at a temperature of 23 ± 2 °C and a relative humidity of 50 ± 10%. All the equipment used was calibrated in accordance with ISO 9001.

[0140]

[0140] In each of the reported examples, 5 to 8 samples were used. The reported G0 values were the average values of these samples.

[0141]

[0141] The distortion energy release rate G0 is the energy required per crack for a cured primary coating initially containing small cracks equal to the slit length b defined in ISO 816 in the test specimens described above. In that case, G0 is calculated as follows. 2 That is, G0 is calculated as follows.

Equation

[0142]

[0142] Next, the G0 value (reported in units of J / m 2 ) of each tested sample was recorded and reported in Table 3 below.

[0143] [Ratio of Tear Strength (G0) to Segment Elastic Modulus (E)]

[0143] First, the ratio of tear strength (G0) to segment elastic modulus was determined by the method described elsewhere in the present specification above. Then, the ratio of these two values was determined by dividing the G0 value of a particular example by its E value. The unit is expressed as J / (m 2 ·MPa). The values for each example were calculated and reported in Table 3 below.

[0144] [Table 3]

[0145] [Discussion of Results] As will be appreciated, the 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, specifically as primary optical fiber coatings, taking into account their tear strength values and / or the ratio of tear strength to segment modulus (G0 / E). Specifically, it has been shown that compositions consisting of reactive oligomers having three arms exhibit significantly higher tear strength than those consisting of reactive oligomers having two arms. This holds regardless of whether the chain length of the longest arm of the two-arm oligomer is shorter or longer than that of the three-arm oligomer.

[0146] Unless otherwise specified, the term wt.% means the amount on a mass basis of a particular component incorporated relative to the entire liquid radiation curable composition.

[0147] In connection with the description of the present invention (especially in connection with the following claims), the use of the terms "a", "an", and "the" and similar reference terms should be construed to include both the singular and the plural forms, unless specifically stated otherwise in this specification or there is an obvious contradiction in the context. The terms "comprising", "having", "including", and "containing" should be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise specified. The recitation of a range of values herein is merely intended to serve as a shorthand notation for referring individually to each value within the range, and each individual value is incorporated herein as if it were individually recited herein. All methods described herein can be performed in any suitable order, unless specifically stated otherwise in this specification or there is an obvious contradiction in the context. The use of any example or exemplary representation provided herein (e.g., "such as") is merely intended to make the present invention better understood and is not intended to limit the scope of the present invention, unless there are claims. No representation in this specification should be construed as suggesting that any non-claim element is essential to the practice of the present invention.

[0148]

[0147] Preferred embodiments of the present invention are described herein, including the best mode known to the inventors for carrying out the present invention. Variations of such preferred embodiments will be apparent to those skilled in the art upon reading the above description. The inventors expect those skilled in the art to utilize such variations as appropriate, and intend for the present invention to be practiced in forms other than those specifically described herein. Accordingly, the present invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Further, all combinations of the elements described above in all possible variations are included in the present invention, unless otherwise specified herein or clearly inconsistent in 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 claimed invention.

Claims

1. An oligomer component, a diluent component, a photoinitiator component, A radiation-curable composition for use as a primary coating for an optical fiber, comprising: The oligomer component includes a reactive urethane oligomer having at least three arms each having a distal end and bound and integrated at a single junction point, and at least one arm is a polyol, a polyisocyanate, an isocyanate-reactive (meth)acrylate, including the reaction product of The reactive urethane oligomer has a number average molecular weight (Mn) and a Z average molecular weight (Mz), The Mn is 10 to 100 kDa, and Mz / Mn is 4.5 to 15, Mn and Mz are measured by size exclusion chromatography (SEC) method, The reactive urethane oligomer has an average (meth)acrylate functionality of 2.2 to 3.8, a radiation-curable composition.

2. The reactive urethane oligomer has an average (meth)acrylate functionality of 2.2 to 3.2, the radiation-curable composition according to claim 1.

3. The theoretical chain length between the junction point and the distal end along the three arms of the reactive urethane oligomer is 4 to 45 kDa, the radiation-curable composition according to claim 1 or 2.

4. The reactive urethane oligomer or oligomer component is present in an amount of 10 to 65 wt.% based on the weight of the total composition, the radiation-curable composition according to any one of claims 1 to 3.

5. At least one arm of the reactive urethane oligomer includes a reaction product of a polyol, a polyisocyanate, and a monohydric alcohol having no (meth)acrylic moiety, the radiation-curable composition according to any one of claims 1 to 4.

6. The reactive urethane oligomer strictly contains three arms, the radiation-curable composition according to any one of claims 1 to 5.

7. The oligomer component includes a reactive urethane oligomer having a theoretical molecular weight of 20 to 100 kDa, the radiation-curable composition according to any one of claims 1 to 6.

8. The junction point of the reactive urethane oligomer is located at the reaction product of a trifunctional core compound, the radiation-curable composition according to any one of claims 1 to 7.

9. The trifunctional core compound includes a polyether triol, the radiation-curable composition according to claim 8.

10. The radiation-curable composition according to claim 9, wherein the polyether triol has a theoretical molecular weight of 5 kDa to 20 kDa.

11. The radiation-curable composition according to any one of claims 8 to 10, wherein the trifunctional core compound contains a triisocyanate.

12. The oligomer component has the following structure (I): 【Chemical 1】 (In the formula, P １ represents the reaction product of a polyether triol, P ２ represents the reaction product of a polyether diol, I １ and I ２ are the same or different and each represents a reaction product of a diisocyanate compound, R １ , R ２ , and R ３ are the same or different and each represents a reaction product of (a) a hydroxy-functional (meth)acrylate or (b) a C １ to C １８ monohydric alcohol having no (meth)acrylic moiety). The radiation-curable composition according to any one of claims 1 to 11, which contains a reactive oligomer represented by.

13. P １ :(I １ + I ２ ):P ２ :(R １ + R ２ + R ３ The radiation-curable composition according to claim 12, wherein the molar ratio of (R ３ + R ２ + R １ ):(I ２ + I １ ):P ２ ):P １ P is 1:6:3:3 to 1:12:9:

3.

14. The oligomer component has the following structure (II): [Chemical 2] (In the formula, I １ represents the reaction product of a triisocyanate compound, P １ represents the reaction product of a polyether polyol, I ２ represents the reaction product of a polyisocyanate compound and R １ 、R ２ 、and R ３ are the same or different, and at least one is (a) a hydroxy-functional (meth)acrylate or (b) a reaction product of a C １ to C １８ monohydric alcohol having no (meth)acrylic moiety). The radiation-curable composition according to any one of claims 1 to 13, which contains a reactive oligomer represented by.

15. The oligomer component has the following structure (III): 【Chemical Formula 3】 (In the formula, P １ represents the reaction product of polyether tetraol, P ２ represents the reaction product of a polyether diol, I １ and I ２ are the same or different and each represents a reaction product of a diisocyanate compound, and R １ 、 R ２ 、 R ３ 、 and R ４ are the same or different, and at least one is (a) a hydroxy-functional (meth)acrylate or (b) a C １ to C １８ monohydric alcohol reaction product). The radiation-curable composition according to any one of claims 1 to 14, which contains a reactive oligomer represented by.

16. The oligomer component has the following structure (IV): [Chemical Formula 4] (In the formula, I １ represents the reaction product of a tetraisocyanate compound, P １ represents the reaction product of a polyether diol, I ２ represents the reaction product of a diisocyanate compound and R １ 、R ２ 、R ３ 、and R ４ are the same or different, and at least one is (a) a hydroxy-functional (meth)acrylate or (b) a C １ to C １８ monovalent alcohol reaction product). The radiation-curable composition according to any one of claims 1 to 15, which contains a reactive oligomer represented by.

17. The radiation-curable composition according to any one of claims 1 to 16, wherein the reactive urethane oligomer has an experimental chain length of 2.5 kDa to 20 kDa, and the experimental chain length is obtained by dividing the Mn of the reactive urethane oligomer by the number of arms.

18. The radiation-curable composition according to any one of claims 1 to 17, wherein the polyol contains polypropylene glycol and / or a copolymer of propylene oxide and ethylene oxide, and one or more of the polyols each have a theoretical molecular weight of 3,000 to 30,000 g / mol.

19. The radiation-curable composition according to any one of claims 1 to 18, wherein the polyisocyanate contains isophorone diisocyanate, 2,4-isomer toluene diisocyanate, 4,4'-methylenedicyclohexyl diisocyanate, 1,5-pentane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, or hexamethylene diisocyanate, or a combination thereof.

20. The radiation-curable composition according to any one of claims 1 to 19, wherein the isocyanate-reactive (meth)acrylate comprises 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 a combination thereof.

21. The radiation-curable composition according to any one of claims 5 to 20, wherein the monohydric alcohol having no (meth)acrylic moiety comprises methanol, ethanol, isopropyl alcohol, butanol, pentanol, 2-ethylhexanol, cetyl alcohol, geraniol, inositol, menthol, or a combination thereof.

22. The diluent component comprises a reactive diluent monomer, and the reactive diluent monomer 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, isodecyl acrylate, or a combination thereof, and / or The photoinitiator component comprises 2,4,6-trimethylbenzoyl ethoxyphenylphosphine oxide, 2,4,6-trimethylbenzoyl diphenylphosphine oxide, α-hydroxycyclohexyl phenyl 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-methylpropan-1-one, or 2-hydroxy-2-methyl-1-[(2-hydroxyethoxy)phenyl]propanone, or a combination thereof, and the radiation-curable composition according to any one of claims 1 to 21.

23. The radiation curable composition is based on the weight of the total radiation curable composition, 10 to 65 wt. % of the urethane oligomer according to any one of claims 1 to 22, 30 wt. % to 85 wt. % of a diluent component, 1 wt. % to 5 wt. % of a photoinitiator component, 1 wt. % to 10 wt. % of an additive component, and comprises the radiation curable composition according to any one of claims 1 to 22.

24. A step of drawing a glass optical fiber through a drawing tower, A step of applying a primary coating composition onto the surface of the glass optical fiber, and Optionally, a step of applying an amount of UV light irradiation sufficient to at least partially cure the primary coating composition, A step of applying a secondary coating composition onto the primary coating composition, By exposing the primary coating composition and the secondary coating composition to at least one radiation source capable of emitting ultraviolet light to cause curing of the primary coating composition and the secondary coating composition, forming a cured primary coating on the surface of the optical fiber and a cured secondary coating on the surface of the cured primary coating, A method for coating an optical fiber, comprising: the primary coating composition being the radiation curable composition according to any one of claims 1 to 23.

25. A primary coating for an optical fiber, which is a cured product of the composition according to any one of claims 1 to 23 and / or is coated by the method according to claim 24.

26. A coated optical fiber comprising a reaction product of the composition according to any one of claims 1 to 23.

27. The coated optical fiber according to claim 26, having an in-situ elastic modulus of 0.15 to 0.8 MPa.

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