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Title:
RADIATION CURABLE LIQUID RESIN COMPOSITION FOR OUTERMOST LAYER OF OPTICAL FIBER
Document Type and Number:
WIPO Patent Application WO/2008/120981
Kind Code:
A1
Abstract:
A curable liquid resin composition for coating an optical fiber outermost layer comprising: (Al) a urethane (meth) aery late having a bisphenol structure; (A2) a urethane (meth)acrylate obtained by reacting an aliphatic polyether polyol, a polyisocyanate, and a hydroxyl group -containing (meth) aery late; (B) a compound having a bisphenol structure and an ethylenically unsaturated group; (C) a compound having an ethylenically unsaturated group other than the components (A1), (A2), and (B); and (D) a polyol compound with a number average molecular weight of 1,500 or more is described and claimed. This composition is suitable for use in coating an optical fiber outermost layer which functions excellently as an optical fiber coating material and produces an optical fiber outermost layer which is hard enough not to be damaged easily and has excellent peelability from the adjacent coating layer.

Inventors:
YAMAGUCHI, Hiroshi (5-6-10 Tsukij, Chuo-ku Tokyo, 104-8410, JP)
KAMO, Satoshi (5-6-10 Tsukij, Chuo-ku Tokyo, 104-8410, JP)
KUROSAWA, Takahiko (5-6-10 TsukijiChuo-ku, Tokyo, 104-8410, JP)
Application Number:
NL2008/050176
Publication Date:
October 09, 2008
Filing Date:
March 28, 2008
Export Citation:
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Assignee:
DSM IP ASSETS B.V. (Het Overloon 1, TE Heerlen, NL-6411, NL)
JSR CORPORATION (5-6-10, TsukijiChuo-ku, Tokyo, 104-8410, JP)
YAMAGUCHI, Hiroshi (5-6-10 Tsukij, Chuo-ku Tokyo, 104-8410, JP)
KAMO, Satoshi (5-6-10 Tsukij, Chuo-ku Tokyo, 104-8410, JP)
KUROSAWA, Takahiko (5-6-10 TsukijiChuo-ku, Tokyo, 104-8410, JP)
International Classes:
C09D4/06; C03C25/00; C08F299/06; C09D11/00; C09D175/00; G02B6/00; G02B6/44
Domestic Patent References:
WO2006049488A1
WO2006025734A1
WO2005026228A1
Foreign References:
US20030119934A1
US20030021943A1
Attorney, Agent or Firm:
HATZMANN, M.J. (Vereenigde, Johan de Wittlaan 7, JR Den Haag, NL-2517, NL)
Download PDF:
Claims:

Claims

1. A curable liquid resin composition for coating an optical fiber outermost layer comprising: (Al) a urethane (meth)acrylate having a bisphenol structure; (A2) a urethane (me th) aery late obtained by reacting an aliphatic poly ether polyol, a polyisocyanate, and a hydroxyl group -containing (meth) acrylate; (B) a compound having a bisphenol structure and an ethylenically unsaturated group; (C) a compound having an ethylenically unsaturated group other than the components (Al), (A2), and (B); and (D) a polyol compound with a number average molecular weight of about 1,500 or more.

2. The curable liquid resin composition according to claim 1, wherein the components (Al) and (B) have a bisphenol A structure.

3. The curable liquid resin composition according to claim 1 or 2, further comprising (E) a silicone compound with an average molecular weight of from about 1500 to about 35,000.

4. An optical fiber outermost coating layer obtained by curing the curable liquid resin composition according to any one of claims 1 to 3.

5. An optical fiber comprising the outermost coating layer according to claim 4.

6. A process to coat one or more optical fibers with the radiation curable liquid resin composition of Claim 1, comprising: a) providing one or more optical fibers coated with one or more curable liquid resin compositions;

b) applying radiation to cure the liquid resin compositions on the one or more optical fibers; c) arranging one or more optical fibers from step b) in a desired configuration; d) applying the radiation curable liquid resin composition of Claim 1 to the one or more optical fibers in the desired configuration of step c); and e) applying radiation to cure the liquid resin composition of Claim 1.

Description:

Title: Radiation curable liquid resin composition for outermost layer of optical fiber

FIELD OF THE INVENTION

The present invention relates to a radiation curable liquid resin composition for coating an optical fiber outermost layer.

BACKGROUND OF THE INVENTION

In the manufacture of optical fibers, a glass fiber is produced by spinning molten glass, and a resin coating is provided over the glass fiber for protection and reinforcement. This step is referred to as fiber drawing. As the resin coating, a structure is known in which a flexible primary coating layer is formed on the surface of an optical fiber and a rigid secondary coating layer is applied over the primary coating layer. A structure is also known in which the resin-coated optical fibers are placed side by side in a plane and bundled with a bundling material to produce a ribbon-shaped coating layer for practical use. A resin composition for forming the primary coating layer is called a primary material, a resin composition for forming the secondary coating layer is called a secondary material, and a resin composition for forming the ribbon-shaped coating layer is called a ribbon matrix material.

The outside diameter of an optical fiber is usually around 250 μm, but is enlarged from about 500 μm to about 900 μm by covering the optical fiber with another resin layer to improve manipulation by hand. Such a resin coating layer is usually referred to as an upjacket layer. Since the upjacket layer itself does not need to have optical properties, transparency is not required. The upjacket layer may be colored to enable visual identification. It is important for the upjacket layer to be peeled off easily without damaging the underlying primary coating layer or secondary coating layer when connecting the optical fiber.

The outermost layer of the optical fiber (i.e. upjacket layer and overcoat layer) may be exposed to air and easily damaged by wind, rain, insects, birds, and the like. Thus, these layers are desired to have a high degree of hardness and not be damaged easily. A curable resin used as an optical fiber coating material including an upjacket layer material is required to have properties such as excellent applicability which allows high-speed fiber drawing, sufficient strength and flexibility, excellent heat resistance, excellent weatherability, excellent resistance to acids and alkalis, excellent oil resistance, low water absorption and hygroscopicity, excellent weatherability, minimal amount of hydrogen gas production, and excellent storage stability in a liquid state.

Since an upjacket layer formed of a known upjacket material firmly adheres to a cable layer in the upper layer or to the primary or secondary coating layer in the lower layer, the upjacket layer is often damaged when the ribbon layer is peeled off to expose the optical fiber, or the primary or secondary coating layer is often damaged when the upjacket layer is peeled off from the optical fiber. This problem lowers workability when connecting the optical fiber.

A composition containing three types of polysiloxane compounds for use as curable liquid resin compositions for forming an upjacket that have improved peelability has been disclosed in JP-A- 10-287717. Compositions containing particles produced from an organic or inorganic material in a resin material have been disclosed in JP-A-9-324136 and JP-A-2000-273127. However, the peelability of the upjacket layer formed of the above compositions is not necessarily sufficient. When covering the upjacket layer with a cable layer which is generally formed of a thermoplastic resin and is provided in the upper layer of the upjacket layer, since the optical fiber is generally heated at about 80 to 120 0 C, the removability of the upjacket layer deteriorates due to the heat history.

SUMMARY OF THE INVENTION

The first aspect of the instant claimed invention is a radiation curable liquid resin composition for coating an optical fiber outermost layer comprising: (Al) a urethane (meth)acrylate having a bisphenol structure;

(A2) a urethane (meth)acrylate obtained by reacting an aliphatic polyether polyol, a polyisocyanate, and a hydroxyl group-containing (meth) acrylate; (B) a compound having a bisphenol structure and an ethylenically unsaturated group; (C) a compound having an ethylenically unsaturated group other than the components (Al), (A2), and (B); and

(D) a polyol compound with a number average molecular weight of about 1,500 or more.

The Second aspect of the instant claimed invention is an optical fiber outermost coating layer obtained by curing the curable liquid resin composition of the first aspect of the instant claimed invention.

The Third aspect of the instant claimed invention is an optical fiber comprising the outermost coating layer of the first aspect of the instant claimed invention. The Fourth aspect of the instant claimed invention is a process to coat one or more optical fibers with the radiation curable liquid resin composition of the First aspect of the instant claimed invention, comprising: a) providing one or more optical fibers coated with one or more curable liquid resin compositions; b) applying radiation to cure the liquid resin compositions on the one or more optical fibers; c) arranging one or more optical fibers from step b) in a desired configuration;

d) applying the radiation curable liquid resin composition of the First aspect of the instant claimed invention to the one or more optical fibers in the desired configuration of step c); e) applying radiation to cure the liquid resin composition of the First aspect of the instant claimed invention.

An object of the present invention is to provide a curable liquid resin composition for coating an optical fiber outermost layer which functions excellently as an optical fiber coating material and produces an optical fiber outermost layer which is hard enough not to be damaged easily and has excellent peelability from the adjacent coating layer.

The inventors of the present invention have prepared urethane (meth)acrylate-containing curable liquid resin compositions using various components, and have evaluated the strength, functions, and peelability of the cured product as the optical-fiber coating layers. As a result, the inventors have found that the above object can be achieved by using a urethane

(me th) aery late having a bisphenol structure, a compound having a bisphenol structure and an ethylenically unsaturated group, compound having an ethylenically unsaturated group, and a specific polyol compound in combination. The inventors of the present invention have prepared urethane

(meth)acrylate-containing curable liquid resin compositions using various components, and have evaluated the strength, functions, and peelability of the cured product as the optical-fiber coating layers. As a result, the inventors have found that the above object can be achieved by using a urethane (meth)acrylate having a bisphenol structure, a compound having a bisphenol structure and an ethylenically unsaturated group, compound having an ethylenically unsaturated group, and a specific polyol compound in combination.

Since, the coating obtained from the curable liquid resin composition of the present invention has very high Young's modulus of elasticity and small

breaking elongation, peelability from the adjacent coating layer is excellent and the coating is not damaged easily. The resin composition is therefore suitable for a coating of the outermost layer of optical fibers, that is, an upjacket layer and an overcoat layer.

Brief Description of the Drawings

FIG. 1 is a conceptual view illustrating a tensile tester. FIG. 2 is a conceptual view illustrating the coating removal stress when removing an upjacket layer.

DETAILED DESCRIPTION OF THE INVENTION

The first aspect of the instant claimed invention is a curable liquid resin composition for coating an optical fiber outermost layer comprising: (Al) a urethane (me th) aery late having a bisphenol structure; (A2) a urethane (meth) aery late obtained by reacting an aliphatic polyether polyol, a polyisocyanate, and a hydroxy 1 group -containing (meth) aery late; (B) a compound having a bisphenol structure and an ethylenically unsaturated group; (C) a compound having an ethylenically unsaturated group other than the components (Al), (A2), and (B); and (D) a polyol compound with a number average molecular weight of about 1,500 or more.

The urethane (meth) aery late used as the component (Al) of the present invention has a bisphenol structure, and is produced by, for example, reacting a polyol having a bisphenol structure, a polyisocyante, and a (meth) aery late containing a hydroxy 1 group. Specifically, the urethane (meth) aery late is produced by reacting isocyanate groups of the diisocyanate with hydroxyl groups of the polyol and the hydroxyl group-containing (meth) aery late.

As the method of reacting these compounds, a method of reacting the polyol, the diisocyanate, and the hydroxyl group -containing (meth) aery late all together; a method of reacting the polyol with the diisocyanate, and reacting the resulting product with the hydroxyl group-containing (meth) aery late; a

method of reacting the diisocyanate with the hydroxyl group -containing (meth)acrylate, and reacting the resulting product with the polyol; a method of reacting the diisocyanate with the hydroxyl group -containing (meth)acrylate, reacting the resulting product with the polyol, and further reacting the resulting product with the hydroxyl group -containing (me th) aery late; and the like can be given.

As examples of the polyol having a bisphenol structure, an alkylene oxide addition polyol bisphenol A, an alkylene oxide addition polyol bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, an alkylene oxide addition polyol of hydrogenated bisphenol A, alkylene oxide addition polyol of hydrogenated bisphenol F, and the like can be given. Of these, a polyol having a bisphenol structure, particularly an alkylene oxide addition polyol of bisphenol A is preferable. These polyols are commercially available as "Uniol DA400", "Uniol DA700", "Uniol DAlOOO", and "Uniol DB400" (manufactured by Nippon Oil and Fats Co., Ltd.), and the like.

As examples of the diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene 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'- dip he nylme thane diisocyanate, 3,3'-dimethylphenylene diisocyanate, 4,4'- biphenylene diisocyanate, 1,6-hexane diisocyanate, isophorone diisocyanate, methylenebis(4-cyclohexylisocyanate), 2,2,4-trimethylhexamethylene diisocyanate, bis(2-isocyanateethyl)fumarate, 6-isopropyl- 1, 3-phenyl diisocyanate, 4-diphenylpropane diisocyanate, lysine diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, tetramethylxylylene diisocyanate, 2,5(or 2,6)- bis(isocyanatemethyl)-bicyclo[2.2.1]heptane, and the like can be given. Of these, 2,4-tolylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, and methylenebis(4-cyclohexylisocyanate) are preferable.

These diisocyanates may be used either individually or in combination of two or more.

As examples of the hydroxyl group -containing (meth)acrylate, 2- hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenyloxypropyl (meth)acrylate, 1,4-butanepolyol mono(meth)acrylate, 2-hydroxyalkyl(meth)acryloyl phosphate, 4- hydroxycyclohexyl (meth) aery late, 1,6-hexanepolyol mono(meth)acrylate, neopentyl glycol mono(meth)acrylate, trimethylolpropane di(meth) aery late, trimethylolethane di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, and (meth)acrylates shown by the following formulas (1) and (2) can be given.

CH 2 =C(R 1 )- COOCH 2 CH 2 - (OCOCH 2 CH 2 CH 2 CH 2 CH 2 )Jr-OH (1)

(2) wherein R 1 represents a hydrogen atom or a methyl group and n is an integer from 1 to 15.

A compound obtained by the addition reaction of (meth)acrylic acid and a glycidyl group -containing compound such as an alkyl glycidyl ether, allyl glycidyl ether, or glycidyl (meth) aery late may also be used. Of these hydroxyl group -containing (meth)acrylates, 2-hydroxyethyl (meth)acrylate and 2- hydroxypropyl (meth)acrylate are preferable.

These hydroxyl group -containing (meth)acrylate compounds may be used either individually or in combination of two or more.

The polyol, the diisocyanate, and the hydroxyl group -containing (meth) aery late are preferably used so that the isocyanate groups included in the diisocyanate and the hydroxyl groups included in the hydroxyl group - containing (meth)acrylate are respectively 1.1 to 3 equivalents and 0.2 to 1.5 equivalents for one equivalent of the hydroxyl groups included in the polyol.

When reacting these compounds, it is preferable to use a urethanization catalyst such as copper naphthenate, cobalt naphthenate, zinc naphthenate, dibutyltin dilaurate, triethylamine, l,4-diazabicyclo[2.2.2]octane, or 2,6,7- trimethyl-l,4-diazabicyclo[2.2.2]octane in an amount of 0.01 to 1 part by mass for 100 parts by mass of the reactants. The reaction temperature is preferably 10 to 9O 0 C, and particularly preferably 30 to 80 0 C.

The hydroxyl group -containing (meth) aery late may be partially replaced with a compound having a functional group which can be added to an isocyanate group. As examples of such compound, y- mercaptotrimethoxysilane, γ-aminotrimethoxysilane, or the like can be given. Use of these compounds improves adhesion to a substrate such as glass.

The content of the urethane (meth)acrylate having a bisphenol structure of the component (Al) in the curable liquid resin composition is preferably from about 5 to about 40 mass%, more preferably from about 10 to about 30 mass%, and particularly preferably from about 15 to about 20 mass%, in order to maintain mechanical characteristics such as high Young's modulus of elasticity, breaking strength, and breaking elongation of the cured product.

The urethane (meth)acrylate obtained by reacting an aliphatic polyether polyol, a polyisocyanate, and a hydroxyl group -containing (meth)acrylate, which is the component (A2) of the present invention, can be produced by reacting the isocyanate group of the diisocyanate with the hydroxyl groups in the aliphatic polyether polyol and the hydroxyl group-containing (meth) aery late.

The urethane (meth)acrylate of the component (A2) can be prepared by the method of synthesizing urethane (meth)acrylate (Al) mentioned above by using an aliphatic polyether polyol instead of the polyol having a bisphenol A structure used in the synthesis of the urethane (meth)acrylate (Al).

As examples of the polyether polyol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, aliphatic polyether

polyols obtained by ring-opening copolymerization of two or more ion- polymerizable cyclic compounds, and the like can be given. As examples of the ion-polymerizable cyclic compound, cyclic ethers such as ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monoxide, isoprene monoxide, vinyloxetane, vinyltetrahydrofuran, vinylcyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, and glycidyl benzoate can be given. A polyether polyol obtained by ring-opening copolymerization of the above ion-polymerizable cyclic compound and a cyclic imine such as ethyleneimine, a cyclic lactonic acid such as β-propyolactone or lactide glycolic acid, or a dimethylcyclopolysiloxane may also be used. As examples of specific combinations of two or more ion-polymerizable cyclic compounds, tetrahydrofuran and propylene oxide, tetrahydrofuran and 2- methyltetrahydrofuran, tetrahydrofuran and 3-methyltetrahydrofuran, tetrahydrofuran and ethylene oxide, propylene oxide and ethylene oxide, butene-1-oxide and ethylene oxide, a ternary polymer of tetrahydrofuran, butene-1-oxide, and ethylene oxide, and the like can be given. The ring- opening copolymer of these ion-polymerizable cyclic compounds may be either a random copolymer or a block copolymer.

The aliphatic polyether polyol is commercially available as "PTMG650", "PTMGlOOO", and "PTMG2000" (manufactured by Mitsubishi Chemical Corp.), "PPG400", "PPGlOOO", "PPG2000", "PPG3000", "EXCENOL 720", "EXCENOL 1020", and "EXCENOL 2020" (manufactured by Asahi Glass Urethane Co.,

Ltd.), "PEGlOOO", "Unisafe DCIlOO", and "Unisafe DC1800" (manufactured by Nippon Oil and Fats Co., Ltd.), "PPTG2000", "PPTGlOOO", "PTG400", and "PTGL2000" (manufactured by Hodogaya Chemical Co., Ltd.), "Z-3001-4", "Z- 3001-5", "PBG2000A", and "PBG2000B" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the like. The copolymer diol of butene-1-oxide and

ethylene oxide is commercially available as "EO/BO500", "EO/BO1000", "EO/BO2000", "EO/BO3000", and "EO/BO4000" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the like.

The content of the urethane (meth)acrylate (A2) obtained by reacting an aliphatic polyether polyol, a polyisocyanate, and a hydroxyl group -containing (meth) aery late in the curable liquid resin composition is preferably from about 10 to about 50 mass%, more preferably from about 20 to about 50 mass%, and particularly preferably from about 20 to about 40 mass% from the viewpoint of mechanical characteristic of the cured product such as Young's modulus of elasticity, breaking strength, and breaking elongation.

In addition to the urethane (meth) aery late (Al) and urethane (meth)acrylate (A2), other urethane (meth) aery late s (urethane (meth) aery late (A3)) may optionally be added to the curable liquid resin composition of the present invention to the extent that the effects of the present invention are not impaired. Although not specifically limited, a urethane (meth)acrylate which does not contain a polyol component and is obtained by reacting a diisocyanate compound and a hydroxyl group-containing (meth)acrylate compound can be given as an example of the urethane (meth)acrylate (A3). As more specific examples of the urethane (meth)acrylate (A3), a urethane (meth)acrylate having a structure in which hydroxyethyl (meth)acrylates are bonded to both ends of 2,4-tolylene diisocyanate, an equimolar reaction product of 2,4-tolylene diisocyanate, hydroxyethyl (meth) aery late, and hydroxypropyl (meth)acrylate, and the like can be given.

The amount of the component (A3), that is, urethane (meth)acrylates other the component (Al) and the component (A2), added to the curable liquid resin composition of the present invention is preferably from about 0 to about 20 mass%, and more preferably from about 0 to about 10 mass%.

The component (B) is a compound having a bisphenol structure and an ethylenically unsaturated group. As examples of such a compound, a (meth)acrylic acid adduct to both ends of bisphenol A diglycidyl ether, a

di(meth)acrylate of polyol of an ethylene oxide or propylene oxide adduct to bisphenol A, a di(meth)acrylate of polyol of an ethylene oxide or propylene oxide adduct to hydrogenated bisphenol A, an epoxy (meth)acrylate obtained by adding (me th) aery late to bisphenol A diglycidyl ether, and the like can be given. Of these, a compound having a bisphenol A structure, particularly a di(meth) aery late of ethylene oxide addition bisphenol A is preferable.

The amount of the component (B) in the curable liquid resin composition is preferably from about 5 to about 50 mass%, more preferably from about 10 to about 40 mass%, and particularly preferably from about 10 to about 35 mass%.

The compound having an ethylenically unsaturated group of component (C) are compounds other than the components (Al), (A2), and (B). When the component (A3) is added, a polymerizable monofunctional compound or a polymerizable polyfunctional compound other than the components (Al), (A2), (A3), and (B) can be used. The polymerizable monofunctional compound refers to a compound having one ethylenically unsaturated group, and the polymerizable polyfunctional compound refers to a compound having two ore more ethylenically unsaturated groups. As examples of the monofunctional compound, vinyl group-containing lactams such as N-vinylpyrrolidone and N- vinylcaprolactam, alicyclic structure -containing (meth)acrylates such as isobornyl (me th) aery late, bornyl (meth)acrylate, tricyclodecanyl (meth)acrylate, and dicyclopentanyl (me th) aery late, benzyl (meth)acrylate, 4- butylcyclohexyl (meth)acrylate, acryloylmorpholine, vinylimidazole, vinylpyridine, and the like can be given. Further examples include 2- hydroxyethyl (meth) aery late, 2-hydroxypropyl (meth) aery late, 2-hydroxybutyl (me th) aery late, methyl (meth) aery late, ethyl (meth) aery late, propyl (meth) aery late, isopropyl (meth) aery late, butyl (meth) aery late, amyl (meth)acrylate, isobutyl (meth) aery late, t-butyl (meth) aery late, pentyl (meth)acrylate, isoamyl (meth) aery late, hexyl (meth) aery late, heptyl (meth)acrylate, octyl (meth) aery late, isooctyl (meth)acrylate, 2-ethylhexyl

(meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (me th) aery late, dodecyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, isostearyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, butoxyethyl (meth)acrylate, ethoxydiethylene glycol (me th) aery late, benzyl (me th) aery late, phenoxyethyl (meth)acrylate, polyethylene glycol mono(meth)acrylate, polypropylene glycol mono(meth) aery late, methoxyethylene glycol (me th) aery late, ethoxyethyl (meth)acrylate, methoxypolyethylene glycol (meth)acrylate, methoxypolypropylene glycol (meth)acrylate, diacetone (meth)acrylamide, isobutoxymethyl (meth)acrylamide, N,N-dimethyl (meth)acrylamide, t-octyl (meth)acrylamide, dimethylaminoethyl (me th) aery late, diethylaminoethyl (meth)acrylate, 7-amino-3,7-dimethyloctyl (meth)acrylate, N,N-diethyl (meth)acrylamide, N,N-dimethylaminopropyl (meth)acrylamide, hydroxybutyl vinyl ether, lauryl vinyl ether, cetyl vinyl ether, 2-ethylhexyl vinyl ether, and compounds shown by the following formulas (3) to (6).

CH 2 =C(R 2 )- CO— (R 3 O) r — R 4 (3) O wherein R 2 represents a hydrogen atom or a methyl group, R 3 represents an alkylene group having 2 to 6, and preferably 2 to 4 carbon atoms, R 4 represents a hydrogen atom or an alkyl group having 1 to 12, and preferably 1 to 9 carbon atoms, and r represents an integer from 0 to 12, and preferably from 1 to 8.

wherein R 5 represents a hydrogen atom or a methyl group, R 6 represents an alkylene group having 2 to 8, and preferably 2 to 5 carbon atoms, R 7 represents a hydrogen atom or a methyl group, and p represents an integer preferably from 1 to 4.

wherein R 8 , R 9 , R 10 , and R 11 individually represent H or CH3, and q represents an integer from 1 to 5.

Of these polymerizable monofunctional compounds, N-vinylpyrrolidone, vinyl group -containing lactam such as N-vinylcaprolactam, isobornyl (meth)acrylate, and lauryl acrylate are preferable.

As the commercially available products of these polymerizable monofunctional compounds, "IBXA" (manufactured by Osaka Organic Chemical Industry Co., Ltd.), "Aronix M-Hl", "Aronix M-113", "Aronix M-114", "Aronix M-117", abd "Aronix TO-1210" (manufactured by Toagosei Co., Ltd.) may be given.

Examples of the polymerizable polyfunctional compounds, trimethylolpropane tri(meth) acrylate, trimethylolpropanetrioxyethyl (meth)acrylate, pentaerythritol tri(meth) acrylate, triethylene glycol diacrylate, tetra-ethylene glycol di(meth) acrylate, tricyclodecanedimethylol diacrylate, 1,4-butanepolyol di(meth)acrylate, 1,6-hexanepolyol di(meth) acrylate, neopentyl glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, neopentyl glycol di(meth) acrylate, pentaerythritol tri(meth) acrylate, pentaerythritol tetra(meth)acrylate, polyester di(meth)acrylate, tris(2- hydroxyethyl)isocyanurate tri(meth) acrylate, tris(2-hydroxyethyl) isocyanulate di(meth)acrylate, tricyclodecanedimethylol diacrylate, triethylene glycol divinyl ether, and compounds shown by the following formula (7):

CH 2 =C(R 12 )-COO— (CH 2 - CH(R 13 )-O) n — CO— C(R l2 )=CH 2 (7)

wherein R 12 and R 13 individually represent a hydrogen atom or a methyl group, and n represents an integer from 1 to 100.

Of these polymerizable polyfunctional compounds, the compounds shown by the formula (7) such as ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, tricyclodecanedimethanol diacrylate, tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate, and tripropylene glycol di(meth) aery late are preferable, with tripropylene glycol di(meth) aery late being particularly preferable. As the commercially available products of these polymerizable polyfunctional compounds, "Yupimer UV" and "SA1002" (manufactured by Mitsubishi Chemical Corp.), "Aronix M-215", "Aronix M-315", and "Aronix M- 325" (manufactured by Toagosei Co., Ltd.), and the like can be given. "Aronix TO-1210" (manufactured by Toagosei Co., Ltd.) may also be used. The amount of the compound having an ethylenically unsaturated group in the curable liquid resin composition is preferably from about 5 to about 50 mass%, more preferably from about 10 to about 40 mass%, and particularly preferably from about 15 to about 40 mass%.

The component (D) which is used in the present invention is a polyol compound having a molecular weight of about 1,500 or more. The addition of the component (D) further improves the peelability of the optical fiber outermost layer formed using the resin composition of the present invention from the adjacent layer. If the molecular weight of the component (D) is less than 1,500, durability may be decreased due to entrance of the component (D) into the ink layer. The molecular weight of the polyol compound is more preferably from about 1,500 to about 10,000, and still more preferably from about 2,000 to about 8,000.

As examples of the polyol compound used as the component (D), a polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone

polyol, and other polyols can be given. There are no specific limitations to the manner of polymerization of the structural units of these polyols, which may be any of random polymerization, block polymerization, and graft polymerization. As examples of the polyether polyol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polydecamethylene glycol, aliphatic polyether polyols obtained by ring-opening copolymerization of two or more ion- polymerizable cyclic compounds, and the like can be given. As examples of the ion-polymerizable cyclic compound, cyclic ethers such as ethylene oxide, propylene oxide, butene-1-oxide, isobutene oxide, 3,3-bischloromethyloxetane, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, dioxane, trioxane, tetraoxane, cyclohexene oxide, styrene oxide, epichlorohydrin, glycidyl methacrylate, allyl glycidyl ether, allyl glycidyl carbonate, butadiene monoxide, isoprene monoxide, vinyloxetane, vinyltetrahydrofuran, vinylcyclohexene oxide, phenyl glycidyl ether, butyl glycidyl ether, and glycidyl benzoate can be given. A polyether polyol obtained by ring-opening copolymerization of the above ion-polymerizable cyclic compound and a cyclic imine such as ethyleneimine, a cyclic lactonic acid such as β-propyolactone or lactide glycolic acid, or a dimethylcyclopolysiloxane may also be used. As examples of the specific combinations of two or more ion-polymerizable cyclic compounds, a combination of tetrahydrofuran and propylene oxide, a combination of tetrahydrofuran and 2-methyltetrahydrofuran, a combination of tetrahydrofuran and 3-methyltetrahydrofuran, a combination of tetrahydrofuran and ethylene oxide, a combination of propylene oxide and ethylene oxide, a combination of butene-1-oxide and ethylene oxide, a ternary polymer of tetrahydrofuran, butene-1-oxide, and ethylene oxide, and the like can be given. The ring-opening copolymer of these ion-polymerizable cyclic compounds may be either a random copolymer or a block copolymer.

These aliphatic polyether polyols are commercially available as "PTMG2Q00" (manufactured by Mitsubishi Chemical Corp.), "PPG2000", "PPG3000", and "EXCENOL 2020" (manufactured by Asahi Glass Urethane Co., Ltd.), "DC1800" (manufactured by Nippon OH and Fats Co., Ltd.), "PPTG2000" and "PTGL2000" (manufactured by Hodogaya Chemical Co.,

Ltd.), "PBG2000A" and "PBG2000B" (manufactured by Daϋchi Kogyo Seiyaku Co., Ltd.), and the like.

As examples of the polyether polyol, cyclic polyether polyols such as alkylene oxide addition polyol of bisphenol A, alkylene oxide addition polyol of bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, alkylene oxide addition polyol of hydrogenated bisphenol A, alkylene oxide addition polyol of hydrogenated bisphenol F, alkylene oxide addition polyol of hydroquinone, alkylene oxide addition polyol of nap hthohydroquinone, alkylene oxide addition polyol of anthrahydroquinone, 1,4-cyclohexanepolyol and alkylene oxide addition polyol thereof, tricyclodecanepolyol, tricyclodecanedimethanol, pentacyclopentadecanepolyol, and pentacyclopentadecanedimethanol can be given. As examples of the cyclic polyether polyol, xylene oxide addition polyol, alkylene oxide addition polyol of bisphenol F, alkylene oxide addition polyol of 1,4-cyclohexanepolyol, and the like can be given. These polyols may be a linear molecule or may have a branched structure. A linear molecule and a branched structure may be present in combination.

It is preferable that the composition contain a polyol having a branched structure, such as an alkyl group represented by a methyl group or an ethyl group, and a hydroxyl group at the terminal of each branched chain, and that the value obtained by dividing the molecular weight of the polyol by the number of hydroxyl groups at the branched chain terminals be from about 500 to about 2,000 (hereinafter called "polyol having a branched structure").

As specific examples of the polyol having a branched structure, polyols obtained by ring-opening polymerization of glycerol, sorbitol, or the like and at

least one compound selected from ethylene oxide, propylene oxide, and butylene oxide are preferable, with polypropylene glycol and a copolymer of butene-1-oxide and ethylene oxide being particularly preferable.

The value obtained by dividing the molecular weight of the polyol by the number of hydroxyl groups at the branched chain terminals is preferably from about 500 to 2,000, and still more preferably from about 1,000 to 1,500. The number average number molecular weight of the polyol is preferably from about 1,500 to about 12,000, more preferably from about 2,000 to about 10,000, and particularly preferably from about 2,500 to about 8,000 as a polystyrene- reduced molecular weight determined by gel permeation chromatography.

The polyol having a branched structure preferably has three to six branched-chain-terminal hydroxyl groups in the molecule.

These polyols are commercially available as "PPG2000", "PPG3000", and "EXCENOL 2020" (manufactured by Asahi Glass Urethane Co., Ltd.), and the like. The copolymer diol of butene-1-oxide and ethylene oxide is commercially available as "EO/BO2000", "EO/BO3000", and "EO/BO4000" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the like.

As the commercially available products of the polyol having a branched structure, "Sunnix GP-3000", "Sunnix GP-3700M", "Sunnix GP-4000", "Sunnix GEP-2800", and "Newpol TL4500N" (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Asahi Glass Urethane Co., Ltd., and Sanyo Chemical Industries, Ltd.), and the like can be given.

The component (D) is added to the composition in an amount of preferably from about 0.1 to about 30 mass%, more preferably from about 5 to about 25 mass%, and particularly preferably from about 5 to about 20 mass% from the viewpoint of ensuring peelability, strength, and weather resistance of the outermost layer.

The curable liquid resin composition of the present invention may further comprise a silicone compound having an average molecular weight of from about 1,500 to about 35,000 as a component (E). The component (E)

plays an important role in obtaining effects of improving peelability for removing the outermost layer optical fibers formed from the resin composition of the present invention from the adjacent layer thereof. If the average molecular weight of the component (E) is less than about 1,500, sufficient effects of improving peelability may not be obtained. If the average molecular weight of the component (D) exceeds about 35,000, the effects of improving peelability may be insufficient. The average molecular weight is more preferably from about 1,500 to about 20,000, still more preferably from about 1,500 to about 20,000, and particularly preferably from about 3,000 to about 15,000.

It is preferable that the component (E) not include a polymerizable group such as an ethylenically unsaturated group. If the component (E) does not contain a polymerizable group, excellent peelability can be maintained even after subjecting the optical fibers to a heat history. As examples of the silicone compound, polyether-modified silicone, alkyl- modified silicone, urethane acrylate-modified silicone, urethane-modified silicone, methylstyryl-modified silicone, epoxy polyether-modified silicone, alkylaralkyl polyether-modified silicone, and the like can be given. Of these, polyether-modified silicone is particularly preferable. As the polyether- modified silicone, a polydimethylsiloxane compound in which at least one silicon atom is bonded to a group R 14 -(R 15 O) S -R 16 - (wherein R 14 represents a hydroxyl group or an alkoxy group having 1 to 10 carbon atoms, R 15 represents an alkylene group having 2 to 4 carbon-atoms (R 15 may have two or more different alkylene groups), R 16 represents an alkylene group having 2 to 12 carbon atoms, and s is an integer of 1 to 20) is preferably used. As R 15 in the above, an ethylene group and a propylene group are preferable, with an ethylene group being particularly preferable. As the commercially available products of the silicone compound which does not include a polymerizable group such as an ethylenically unsaturated group, "SH28PA" (manufactured by Dow Corning Toray Co., Ltd., dimethylpolysiloxane-polyoxyalkylene

copolymer), "Paintad 19" and "Paintad 54" (manufactured by Dow Corning Toray Co., Ltd., dimethylpolysiloxane-polyoxyalkylene copolymer), "Silaplane FM0411" (manufactured by Chisso Corp.), "SF8428" (manufactured by Dow Corning Toray Co., Ltd., dimethylpolysiloxane-polyoxyalkylene copolymer (including side chain OH)), "BYKUV3510" (manufactured by BYK-Chemie Japan., dimethylpolysiloxane-polyoxyalkylene copolymer), "DC57" (manufactured by Dow Corning Toray Co., Ltd., dimethylpolysiloxane- polyoxyalkylene copolymer), and the like can be given. As the commercially available products of the silicone compound which has a polymerizable group such as an ethylenically unsaturated group, "TegoRad 2300" and "TegoRad 2200N" (manufactured by Tego Chemie Service) can be given.

The component (E) is added to the composition in an amount of preferably from about 0.1 to about 50 mass%, more preferably from about 5 to about 40 mass%, and particularly preferably from about 1 to about 20 mass% from the viewpoint of ensuring peelability, strength, and weather resistance of the outermost layer.

The curable liquid resin composition of the present invention may further comprise a polymerization initiator (F). As the polymerization initiator, a heat polymerization initiator or a photoinitiator may be used. When the curable liquid resin composition of the present invention is heat curable, a heat polymerization initiator such as a peroxide or azo compound is usually used. As specific examples of the heat polymerization initiator, benzoyl peroxide, t-butyloxybenzoate, azobisisobutyronitrile, and the like can be given. A photoinitiator is used when the curable liquid resin composition of the present invention is photo -curable. It is preferable to use a photosensitizer in combination, if required. As examples of the photoinitiator, 1- hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenylacetophenone, xanthone, fluorenone, benzaldehyde, fluorene, anthraquinone, triphenylamine, carbazole, 3-methylacetophenone, 4-chlorobenzophenone, 4,4'-

dimethoxybenzophenone, 4,4'-diaminobenzophenone, Michler's ketone, benzoin propyl ether, benzoin ethyl ether, benzyl methyl ketal, l-(4-isopropylphenyl)-2- hydroxy-2-methylpropan- 1-one, 2-hydroxy-2-methyl- 1-phenylpropan- 1-one, thioxanethone, diethylthioxanthone, 2-isopropylthioxanthone, 2- chlorothioxanthone, 2-methyl- 1- [4-(methylthio)phenyl] -2-morphohno-propan- 1- one, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis-(2,6- dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide; "IRGACURE 184", "IRGACURE 369", "IRGACURE 651", "IRGACURE 500", "IRGACURE 907", "CGI 1700", "CGI 1750", "CGI 1850", "CG24-61", "Darocure 1116", and "Darocure 1173" (manufactured by Ciba Specialty Chemicals Co.); "Lucirin TPO" (manufactured by BASF); "Ubecryl P36" (manufactured by UCB); and the like can be given.

As examples of the photosensitizer, trie thyl amine, diethylamine, N- methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4- dime thy laminobenzoate, ethyl 4-dimethylaminobenzoate, isoamyl 4- dimethylaminobenzoate; Ubecryl P102, 103, 104, 105 (manufactured by UCB); and the like can be given.

When curing the curable liquid resin composition of the present invention using heat and ultraviolet rays, the heat polymerization initiator and the photoinitiator can be used in combination. The content of the polymerization initiator in the composition is preferably from about 0.1 to about 10 mass%, and particularly preferably from about 0.3 to about 7 mass%.

Various additives such as antioxidants, coloring agents, UV absorbers, light stabilizers, silane coupling agents, heat polymerization inhibitors, leveling agents, surfactants, preservatives, plasticizers, lubricants, solvents, fillers, aging preventives, wettability improvers, and coating surface improvers may be optionally added to the curable liquid resin composition of the present invention insofar as the characteristics of the present invention are not adversely affected.

The composition of the present invention is cured by applying heat or radiation. Radiation used herein refers to infrared rays, visible light, ultraviolet rays, X-rays, electron beams, α-rays, β-rays, γ-rays, and the like.

A cured film obtained by curing the curable liquid resin composition preferably has Young's modulus of elasticity preferably of from about 600 to about 1,500 MPa, and more preferably from about 700 to about 1,300 MPa. In addition, the cured product has breaking elongation preferably of from about 5 to about 50%, and more preferably from about 15 to about 40%.

The instant claimed invention also includes a process to coat one or more optical fibers with the radiation curable liquid resin composition of this invention, comprising: a) providing one or more optical fibers coated with one or more curable liquid resin compositions; b) applying radiation to cure the liquid resin compositions on the one or more optical fibers; c) arranging one or more optical fibers from step b) in a desired configuration; d) applying the radiation curable liquid resin composition of this invention to the one or more optical fibers in the desired configuration of step c); and e) applying radiation to cure the liquid resin composition of this invention.

It is known in the art how to manufacture optical fibers and coat them with one or more radiation curable liquid resin compositions. The one or more radiation curable liquid resin compositions may include a Primary Coating, a Secondary Coating and an Ink Coating. Primary Coatings, Secondary Coatings and Ink Coatings for optical fiber are commercially available from JSR Corporation in Japan, http://www.jsr.co.;ip/]sr e/ and are also commercially available from DSM Desotech in the United States, http://www.dsm.com/en US/html/dsmd/desotech home.htm

and other countries.

It is also known in the art how to cure the one or more radiation curable liquid resin compositions. When forming an upjacket layer, the composition is applied to a thickness of from about 100 to about 350 μm. One or more optical fibers coating with the radiation curable liquid resin composition of the instant claimed invention would have good utility in the optical fiber industry.

A cable layer formed of a thermoplastic resin may be provided on the outer surface of the optical fiber upjacket layer.

The present invention will be described in more detail by way of examples, which should not be construed as limiting the present invention.

EXAMPLES Preparation Example 1: synthesis 1 of urethane (me th) aery late (Al)

A reaction vessel equipped with a stirrer was charged with 0.120 g of 2,6-di-t-butyl-p-cresol, 354.86 g of 2,4-tolylene diisocyanate, and 0.240 g of dibutyltin dilaurate. The mixture was cooled to 15 0 C while stirring. After the addition of 236.60 g of hydroxyethyl acrylate dropwise while controlling the temperature at 2O 0 C or less, the mixture was stirred at 4O 0 C in a water bath for one hour. Then, after cooling to 2O 0 C, 407.51 g of ethylene oxide addition diol of bisphenol A ("DA400" manufactured by NOF Corp.) was added. After confirming generation of heat, the mixture was stirred at 65 0 C for three hours and the reaction was terminated when the remaining isocyanate was reduced to 0.1 mass% or less. The resulting urethane (meth) acrylate (A) is referred to as "UA-I".

The resulting urethane (meth) acrylate has a structure having 2- hydroxyethyl acrylate bonded to both ends of a diol having a bisphenol A structure via 2,4-tolylene diisocyanate.

Preparation Example 2: synthesis 1 of urethane (meth)acrylate (A2)

A reaction vessel equipped with a stirrer was charged with 0.240 g of 2,6-di-t-butyl-p-cresol, 271.72 g of tolylene diisocyanate, and 546.07 g of polypropylene glycol with a number average molecular weight of 700. The mixture was cooled to 15 0 C. After the addition of 0.799 g of dibutyltin dilaurate, the mixture was stirred for one hour while controlling the liquid temperature at less than 4O 0 C. The mixture was cooled with ice to 15 0 C or less with stirring. After the drop wise addition of 181.17 g of hydroxyethyl aery late, the mixture was allowed to react for one hour with stirring while controlling the liquid temperature at 2O 0 C or less. The mixture was then stirred at 70 to 75 0 C for three hours. The reaction was terminated when the residual isocyanate content became 0.1 mass% or less. The resulting urethane (meth)acrylate (A) is referred to as "UA-2".

The resulting urethane (meth)acrylate has a structure having 2- hydroxyethyl acrylate bonded to both ends of propylene glycol via 2,4-tolylene diisocyanate.

Preparation Example 3: synthesis of urethane (meth) acrylate (A3)

A reaction vessel equipped with a stirrer was charged with 0.240 g of 2,6-di-t-butyl-p-cresol, 428.10 g of 2,4-tolylene diisocyanate, and 0.799 g of dibutylin dilaurate. The mixture was cooled to 15 0 C while stirring. After the addition of 570.86 g of hydroxyethyl acrylate dropwise while controlling the temperature at 2O 0 C or less, the mixture was stirred at 4O 0 C in a water bath for one hour. After confirming that the temperature does not increase, the mixture was stirred at 65 0 C for three hours and the reaction was terminated when the remaining isocyanate was reduced to 0.1 mass% or less. The resulting urethane (meth) acrylate (A) is referred to as "UA-3".

The resulting urethane (meth)acrylate has a structure having 2- hydroxyethyl acrylate bonded to both ends of 2,4-tolylene diisocyanate. Examples 1 to 3 and Comparative Examples 1 to 3

A reaction vessel equipped with a stirrer was charged with the components listed in Table 1. The mixture was then stirred for one hour while controlling the liquid temperature at 5O 0 C to obtain a curable liquid resin composition.

Test Example

The curable liquid resin compositions obtained in the above examples and comparative examples were cured using the following method to prepare specimens. The specimens were evaluated as follows. The results are shown in Table 1.

1. Young's modulus

The curable liquid resin composition was applied to a glass plate using applicator bar for a 250 μm thickness film. The coating was cured by applying ultraviolet rays at a dose of 1 J/cm 2 in air to obtain a film for measuring the Young's modulus. The film was cut into a strip-shaped sample with a width of 6 mm and a length of 25 mm (portion to be pulled). The sample was subjected to a tensile test at a temperature of 23 0 C and a humidity of 50%. The Young's modulus was calculated from the tensile strength at a strain of 2.5% and a tensile rate of 1 mm/min. 2. Breaking strength and breaking elongation

Breaking strength and breaking elongation of the test sample were measured using a tensile tester ("AGS-50G" manufactured by Shimadzu Corp.) Tensile rate 50 mm/min

Benchmark distance (measurement distance) 25 mm Measurement temperature 23 0 C

Relative humidity 50% RH

3. Peelability

A primary coating material ("Rl 164" manufactured by JSR Corporation), a secondary coating material ("R3180" manufactured by JSR Corporation), and an ink material ("FS blue ink" manufactured by T & K Toka

Company) were applied to a glass fiber and cured by applying ultraviolet rays using a rewinder model (manufactured by Yoshida Kogyo Co., Ltd.) to produce a resin-coated optical fiber with an outer diameter of 250 μm. An upjacket layer was formed over the resin-coated optical fiber by applying the curable composition listed in Table 1 and curing the applied composition using ultraviolet rays to obtain an upjacketed optical fiber with an outer diameter of 500 μm. A resin sheet with a thickness of 1 mm was formed using magnesium hydroxide -containing flame -retardant polyethylene resin pellets by hot pressing (press conditions: press pressure 60 kgf/cm 2 , 180 0 C x 3 min). The upjacketed optical fiber was placed between the flame -retardant polyethylene resin sheets and hot-pressed (press conditions: press pressure 1 kgf/cm 2 , 18O 0 C x 1 min) to produce a cable-like measurement specimen.

As shown in FIG. 1, the cable-like specimen was held using a hot stripper (manufactured by Furukawa Electric Co., Ltd.) at a position 3 cm from the end. The specimen was then pulled at a tensile rate of 50 m/min using a tensile tester (manufactured by Shimadzu Corp.) to measure the coating removal stress (maximum stress shown in FIG. 2) when removing the upjacket layer. The measurement was carried out immediately after the preparation of the cable-like measurement specimen.

In Table 1,

"Irgacure 184": 1-hydroxycyclohexyl phenyl ketone (manufactured by Ciba Specialty Chemicals Co., Ltd.)

"Lucirin TPO": 2,4,6-trimethylbenzoyldiphenylphosphine oxide (manufactured by Ciba Speciality Chemicals Co., Ltd.)

"Irganox 245": ethylenebis(oxyethylene)bis[3-(5-tert-butyl-4-hydroxy-m-toly l)- propionate] (manufactured by Ciba Specialty Chemicals Co., Ltd.) "SH28PA": dimethylpolysiloxane polyoxyalkylene copolymer (manufactured by Toray-Dow Corning Co., Ltd.)

As shown in Table 1, since the cured product formed from the resin composition of the present invention has high Young's modulus of elasticity and small breaking elongation, the coating layer exhibits excellent peelability from the adjacent layer and is damaged only with difficulty. The resin composition of the present invention is therefore suitable for a coating of the outermost layer of optical fibers such as an upjacket layer, an overcoat layer, and the like.

All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non- claimed element as essential to the practice of the invention.

Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention.

Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above- described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.