JPH08269392A - Active energy beam-curing type composition for primary coating of optical fiber - Google Patents

Abstract

PURPOSE: To obtain the subject composition having excellent curing property and giving a cured film having excellent heat resistance, hydrolysis resistance, water absorption resistance and low tensile elastic modulus, comprising a compound having an oxetane ring and a photo-cationic polymerization initiator. CONSTITUTION: The objective active energy beam-curing type composition for primary coating of an optical fiber having excellent curing property and giving a cured film having excellent resistances, against heat, hydrolysis and water absorption, etc., is obtained by mixing a compound having 1-4 pieces of oxetane rings expressed by formula I (R<1> is H or a 1-6C alkyl; R<2> is a 1-6C alkyl), formula II [R<3> is an alkylene, a poly(alkyleneoxy) or carbonyl, etc.] and formula III (R<9> is a trifunctional or a tetrafunctional organic group; (j) is 3 or 4), etc., with a photocationic polymerization initiator (e.g. benzophenone), and further, as necessary adding at least one kind among a compound having an epoxy group, a compound having a vinyl ether group and a compound having (meth) acryloyl group, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active energy ray-curable composition for optical fiber primary coating, which comprises a compound having an oxetane ring.
It is used in the field of use and information and communication. In addition, in this specification, an acryloyl group or a methacryloyl group is represented as a (meth) acryloyl group.

[0002]

2. Description of the Prior Art Optical fibers are very fragile and easily damaged.
Moreover, it is well known that optical transmission loss increases due to contamination. For this reason, it has been conventionally performed that an optical fiber is first coated with a material having a low elastic modulus immediately after spinning the optical fiber and then secondly coated with a material having a higher elastic modulus. There is. In recent years, as a material for primary coating of such an optical fiber, a composition which is cured by irradiation with an active energy ray has been used because of its excellent productivity. As the active energy ray-curable composition used for this purpose, a composition composed of unsaturated polyurethane that is cured by active energy ray-initiated radical polymerization, specifically, a composition composed of polyether urethane acrylate is often used. . Examples of the polyether polyol component which is a raw material of the polyether urethane acrylate used here include polyethylene glycol, polypropylene glycol,
Examples include polybutylene glycol, polytetramethylene glycol, copolymers of propylene oxide and ethylene oxide, copolymers of tetrahydrofuran and propylene oxide, and alkylene oxide adducts of bisphenol A. Among them, polyether urethane acrylates produced from polyethylene glycol as a raw material have been widely used, but compositions composed of the polyether urethane acrylates have not been sufficiently resistant to hydrolysis and water absorption, and thus have been recently used. In this regard, a polyether urethane acrylate produced from polypropylene glycol or polytetramethylene glycol, which has excellent physical properties, is widely used. However, a composition comprising polyether urethane acrylate produced using polypropylene glycol has a low viscosity and excellent workability, but has a drawback that curability and heat resistance of the cured film are not sufficient. There is. On the other hand, a composition made of polyether urethane acrylate produced using polytetramethylene glycol has excellent curability and heat resistance of the cured film, but has high crystallinity and becomes a solid at room temperature, and thus workability is improved. In addition, since the cured film has a high tensile modulus, it is necessary to add a reactive diluent such as low molecular weight (meth) acrylate in order to prepare a material with a low tensile modulus. The addition of the diluent has a problem that the heat resistance of the cured film of the composition is lowered. In order to improve these drawbacks, a composition comprising a polyether urethane acrylate produced by using a copolymer of tetrahydrofuran and propylene oxide as a polyether polyol component has been studied, but the curability, heat resistance and the like are still unsatisfactory. It is enough.

As an active energy ray curing technique other than the active energy ray initiated radical polymerization, an active energy ray initiated cationic polymerization technique has been put into practical use. In particular, the active energy ray-initiated cationic polymerization is not inhibited by oxygen, so there is no limitation that it must be carried out in an inert atmosphere, and it has the advantage that rapid and complete polymerization can be carried out in air. To date, active energy ray initiated cationic polymerization techniques have focused on the polymerization of two types of monomers: epoxy resins and vinyl ethers. In particular, the photocurable epoxy resin has excellent adhesiveness, and the cured film has good heat resistance and chemical resistance. However, many conventional photocurable epoxy resins have a relatively slow photopolymerization rate, which causes a problem in production efficiency. on the other hand,
Many photocurable vinyl ethers are volatile and have a strong odor, shrinkage during curing is recognized as compared with photocurable epoxy, adhesion is not sufficient, and water resistance and hydrolysis resistance are also high. Was not enough.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have solved these problems and have excellent curability, and the cured film has long-term reliability such as heat resistance, hydrolysis resistance and water absorption resistance. The inventors have made earnest studies to find an active energy ray-curable composition suitable for a primary coating of an optical fiber having excellent and low tensile modulus.

[0005]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted various studies to find that a composition comprising a cyclic ether having a specific structure has been identified as an active energy ray-curable composition for primary coating of optical fibers. They have found that they can be solved and completed the present invention. That is, the first invention of the present invention is an active energy ray-curable composition for optical fiber primary coating, which comprises a compound having 1 to 4 oxetane rings and a photocationic polymerization initiator, and the second invention is a compound having an epoxy group. An active energy ray-curable composition for optical fiber primary coating of the first invention, further comprising: an active energy ray for optical fiber primary coating of the first invention or the second invention, further comprising a compound having a vinyl ether group. Curable composition, 4th invention is 1st which further contains the compound which has a (meth) acryloyl group, and a photoradical polymerization initiator.
The active energy ray-curable composition for optical fiber primary coating of the invention, the second invention or the third invention. Hereinafter, the present invention will be described in detail.

Compound Having 1 to 4 Oxetane Rings The compound having an oxetane ring used in the present invention has 1 to 4 oxetane rings. When a compound having 5 or more oxetane rings is used, the cured film of the composition loses flexibility, and physical properties suitable for use as an optical fiber primary coating cannot be obtained. As the compound having an oxetane ring used in the present invention, various compounds can be used as long as they are compounds having 1 to 4 oxetane rings. Examples of the compound having one oxetane ring include compounds represented by the following general formula (1).

[0007]

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In the formula (1), R ¹ is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, a fluoroalkyl group having 1 to 6 carbon atoms, It is an allyl group, an aryl group, a furyl group or a thienyl group. R ² is an alkyl group having 1 to 6 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, 1-
Alkenyl having 2 to 6 carbon atoms such as propenyl group, 2-propenyl group, 2-methyl-1-propenyl group, 2-methyl-2-propenyl group, 1-butenyl group, 2-butenyl group or 3-butenyl group. Group, phenyl group, benzyl group,
A group having an aromatic ring such as fluorobenzyl group, methoxybenzyl group or phenoxyethyl group, alkylcarbonyl group having 2 to 6 carbon atoms such as ethylcarbonyl group, propylcarbonyl group or butylcarbonyl group, ethoxycarbonyl group, propoxycarbonyl group Alternatively, it is an alkoxycarbonyl group having 2 to 6 carbon atoms such as butoxycarbonyl group, or an N-alkylcarbamoyl group having 2 to 6 carbon atoms such as ethylcarbamoyl group, propylcarbamoyl group, butylcarbamoyl group or pentylcarbamoyl group. .

Next, examples of the compound having two oxetane rings include compounds represented by the following general formula (2).

[0010]

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In the formula (2), R ¹ is the same group as in the general formula (1). R ³ is, for example, a linear or branched alkylene group such as ethylene group, propylene group or butylene group, poly (ethyleneoxy)
Group or a linear or branched poly (alkyleneoxy) group such as a poly (propyleneoxy) group, a propenylene group, a linear or branched unsaturated hydrocarbon group such as a methylpropenylene group or a butenylene group, a carbonyl group, An alkylene group containing a carbonyl group, an alkylene group containing a carboxyl group, an alkylene group containing a carbamoyl group, and the like.
R ³ is also a polyvalent group selected from the groups represented by the following formulas (3), (4) and (5).

[0012]

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In the formula (3), R ⁴ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, a methoxy group, an ethoxy group, a propoxy group or a butoxy group. An alkoxy group having 1 to 4 carbon atoms such as, a halogen atom such as a chlorine atom or a bromine atom,
It is a nitro group, a cyano group, a mercapto group, a lower alkylcarboxyl group, a carboxyl group, or a carbamoyl group.

[0014]

[Chemical 4]

In the formula (4), R ⁵ is an oxygen atom, a sulfur atom, a methylene group, NH, SO, SO ₂ , C (C
F ₃ ) ₂ or C (CH ₃ ) ₂ .

[0016]

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In the formula (5), R ⁶ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or an aryl group. n is 0 to 20
00 is an integer. R ⁷ is an alkyl group having 1 to 4 carbon atoms such as methyl group, ethyl group, propyl group or butyl group,
Or, it is an aryl group. R ⁷ is also a group selected from the groups represented by the following formula (6).

[0018]

[Chemical 6]

In the formula (6), R ⁸ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group and a butyl group, or an aryl group. m is 0 to 100
Is an integer. Specific examples of the compound having two oxetane rings include compounds represented by the following formulas (7) and (8).

[0020]

[Chemical 7]

The compound represented by the formula (7) is a compound of the formula (2) in which R ¹ is an ethyl group and R ³ is a carboxyl group.

[0022]

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The compound represented by the formula (8) is the compound of the general formula (2), wherein R ¹ is an ethyl group and R ³ is a group represented by the formula (5).
^A compound in which ⁶ and R ⁷ are methyl groups and n is 1.

Of the compounds having two oxetane rings, preferred examples other than the above compounds include compounds represented by the following general formula (9). In the formula (9), R ¹ is the same group as in the general formula (1).

[0025]

[Chemical 9]

Examples of the compound having 3 to 4 oxetane rings include compounds represented by the following general formula (10).

[0027]

[Chemical 10]

In the formula (10), R ¹ is the same group as in the general formula (1). R ⁹ represents, for example, a group represented by the following formulas (11) to (13) having 1 to 1 carbon atoms.
And 12 branched alkylene groups, branched poly (alkyleneoxy) groups such as the group represented by the following formula (14), branched polysiloxy groups such as the group represented by the following formula (15), and the like. j is 3 or 4.

[0029]

[Chemical 11]

[In the formula (11), R ¹⁰ is a methyl group,
A lower alkyl group such as an ethyl group or a propyl group. ]

[0031]

[Chemical 12]

[0032]

[Chemical 13]

[0033]

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[In the formula (14), l is an integer of 1 to 10. ]

[0035]

[Chemical 15]

Specific examples of the compound having 3 to 4 oxetane rings include compounds represented by the following formula (16).

[0037]

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Further, as an example of the compound having 1 to 4 oxetane rings other than the above, there is a compound represented by the following formula (17).

[0039]

[Chemical 17]

In the formula (17), R ⁸ is the same group as in the formula (6). R ¹¹ is an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a propyl group or a butyl group, or a trialkylsilyl group, and r is 1 to 4.

Specific preferred examples of the oxetane compound used in the present invention include the compounds shown below.

[0042]

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[0043]

[Chemical 19]

[0044]

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[0045]

[Chemical 21]

In addition to these, the molecular weight is from 1000 to 5
A compound having a high molecular weight of about 000 and having 1 to 4 oxetane rings is also included. Examples of these include the following compounds.

[0047]

[Chemical formula 22]

Here, p is 20 to 200.

[0049]

[Chemical formula 23]

Here, q is 15 to 100.

[0051]

[Chemical formula 24]

Here, s is 20 to 200.

Photocationic Polymerization Initiator As the photocationic polymerization initiator used in the composition of the present invention, various kinds can be used. Preferred examples of these initiators include diaryliodonium salts and triarylsulfonium salts. A typical cationic photopolymerization initiator is shown below.

[0054]

[Chemical 25]

[0055]

[Chemical formula 26]

[0056]

[Chemical 27]

[0057]

[Chemical 28]

In the formula, R ¹² is a hydrogen atom and has 1 to 18 carbon atoms.
Or an alkoxy group having 1 to 18 carbon atoms, R ¹³ is a hydrogen atom, a hydroxyalkyl group or a hydroxyalkoxy group, and preferably a hydroxyethoxy group. M is a metal, preferably antimony,
X is halogen, preferably fluorine, and k is the valence of the metal, for example 5 in the case of antimony. The cationic photopolymerization initiator is a compound having an oxetane ring and / or a compound having an epoxy group.
Alternatively, when a compound having a vinyl ether group is contained, it is preferably contained in a proportion of 0.1 to 20% by weight, more preferably 0.1 to 20% by weight based on the total amount thereof.
It is 10% by weight. If the amount is less than 0.1% by weight, the curability is not sufficient. On the other hand, if the amount exceeds 20% by weight, the light transmittance is poor and uniform curing cannot be performed or the coating surface is not smooth. The sex may be lost.

In each of the above chemical formulas showing a compound having 1 to 4 oxetane rings or a photocationic polymerization initiator, each group represented by the same symbol existing in one molecule may be the same as each other. It can be different.

Other Blends In addition to the above-mentioned essential ingredients, other ingredients may be blended in the composition of the present invention, if necessary. A second invention of the present invention is an active energy ray-curable composition for optical fiber primary coating, which further comprises a compound having an epoxy group in the composition of the first invention. In this case, by including an epoxy compound in the composition, the curing rate of the composition can be further improved. Various compounds can be used as the compound having an epoxy group. For example, examples of the epoxy compound having one epoxy group include phenylglycidyl ether and butylglycidyl ether, and examples of the epoxy compound having two or more epoxy groups include hexanediol diglycidyl ether, tetraethylene glycol diglycidyl ether, triglyceride. Examples thereof include methylolpropane triglycidyl ether, bisphenol A diglycidyl ether and novolac type epoxy compounds. Particularly in the present invention, it is preferable to use an alicyclic epoxy compound, and examples thereof include the compounds shown below.

[0061]

[Chemical 29]

[0062]

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[0063]

[Chemical 31]

In this case, the compounding ratio of the compound having an epoxy group is 5 to 95 parts by weight based on 100 parts by weight of the total amount of the compound having 1 to 4 oxetane rings and the compound having an epoxy group. preferable.

A third invention of the present invention is an active energy ray-curable composition for optical fiber primary coating, which further comprises a compound having a vinyl ether group in the composition of the first invention or the second invention. In this case, by including the compound having a vinyl ether group in the composition, the curing rate of the composition can be further improved. Various compounds can be used as the compound having a vinyl ether group.
For example, examples of the compound having one vinyl ether group include hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, dodecyl vinyl ether, propenyl ether propylene carbonate and cyclohexyl vinyl ether. 2 vinyl ether groups
Examples of the compound having two or more thereof include cyclohexanedimethanol divinyl ether, triethylene glycol divinyl ether, and novolac type divinyl ether. In this case, as the compounding ratio of the compound having a vinyl ether group, the total amount of the compound having 1 to 4 oxetane rings and the compound having a vinyl ether group is 1
5 to 95 parts by weight is preferable with respect to 00 parts by weight.

The fourth invention of the present invention is for the primary coating of an optical fiber, which comprises the composition of the first invention, the second invention or the third invention, further containing a compound having a (meth) acryloyl group and a photoradical polymerization initiator. It is an active energy ray-curable composition. In this case, by including a compound having a (meth) acryloyl group in the composition, the composition viscosity can be adjusted and the coating film hardness of the composition can be modified. Various compounds can be used as the compound having a (meth) acryloyl group. For example, a (meth) acryloyl group is 1
Examples of the compound having an individual include (meth) acrylates of phenol, nonylphenol and 2-ethylhexanol, and (meth) acrylates of alkylene oxide adducts of these alcohols. (Meta)
Examples of the compound having two acryloyl groups include bisphenol A, isocyanuric acid, di (meth) acrylate of ethylene glycol and propylene glycol, and di (meth) acrylate of an alkylene oxide adduct of these alcohols. Examples of compounds having three (meth) acryloyl groups include penta (erythritol), tri (meth) acrylate of trimethylolpropane and isocyanuric acid, and tri (meth) acrylate of an alkylene oxide adduct of these alcohols. Examples of the compound having four or more acryloyl groups include pentaerythritol and poly (meth) acrylate of dipentaerythritol. Further, conventionally known acrylic-based monomers / oligomers such as urethane acrylate having a urethane bond as a main chain, polyester acrylate having an ester bond as a main chain, and epoxy (meth) acrylate obtained by adding acrylic acid to an epoxy compound are also included. In this case (meta)
The compounding ratio of the compound having an acryloyl group is preferably 5 to 95 parts by weight based on 100 parts by weight of the total amount of the compound having 1 to 4 oxetane rings and the compound having a (meth) acryloyl group. In the fourth aspect of the present invention, a photoradical polymerization initiator is added to the composition.
As the photo-radical polymerization initiator, various ones can be used, and preferred ones are benzophenone and its derivatives, benzoin alkyl ether, 2-methyl [4- (methylthio) phenyl] -2-morpholino-
1-propanone, benzyl dimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, alkylphenyl glyoxylate, diethoxyacetophenone, 2-benzyl-2-dimethyl Amino-1- (4-
Examples thereof include morpholinophenyl) -1-butanone and acylphosphine oxide. The content of these photoradical polymerization initiators is preferably 0.01 to 20% by weight based on the compound having a (meth) acryloyl group.

Further, in the present invention, the composition of the first invention contains one or more selected from the compounds having an epoxy group, the compound having a vinyl ether group and the compound having a (meth) acryloyl group. It can also be blended. In this case, as the compounding ratio of these, the total amount of the compound having a curable component having 1 to 4 oxetane rings, the compound having an epoxy group, the compound having a vinyl ether group and the compound having a (meth) acryloyl group is used. The amount of the compound having 1 to 4 oxetane rings is preferably 5 to 95 parts by weight based on 100 parts by weight.

The composition of the present invention comprises inactive ingredients such as inorganic fillers, dyes, pigments, viscosity modifiers, treating agents and UV blockers in amounts of up to 100 parts by weight per 100 parts by weight of curable components. It can be blended.

In addition to the photocationic polymerization initiator and / or the photoradical polymerization initiator, a photosensitizer may be added to the composition of the present invention to adjust the wavelength in the UV region. Typical sensitizers that can be used in the present invention include Clevero [JV Crivello, Adv. In Polymer Sc
i., 62, 1 (1984)], and specific examples thereof include pyrene, perylene, acridine orange, thioxanthone, 2-chlorothioxanthone and benzoflavin.

○ Production and Use Method The production method of the composition of the present invention is not particularly limited, and the essential components of the present invention, or the essential components and other components as necessary are stirred by a commonly used method. Alternatively, it can be obtained by mixing. The method of using the composition of the present invention may also be according to the method conventionally used for the optical fiber primary coating.
For example, a method of applying the composition of the present invention to the surface of an optical fiber and then irradiating it with an active energy ray to cure the composition may be used. The optical fiber to which the composition of the present invention is applied can be applied to various types, and the film thickness of the composition may be appropriately selected according to the purpose of use. Examples of active energy rays include ultraviolet rays, X-rays, and electron rays. As a light source that can be used when curing with ultraviolet rays,
Various materials can be used, and examples thereof include a pressurized or high-pressure mercury lamp, a metal halide lamp, a xenon lamp, an electrodeless discharge lamp or a carbon arc lamp.
In the case of curing with an electron beam, various irradiation devices can be used, and examples thereof include Cockloft-Waltsin type, Van de Graaff type, and resonance transformer type.
Those having an energy of 0 to 1000 eV are preferable,
More preferably, it is 100 to 300 eV. In the present invention, it is preferable to use ultraviolet rays for curing the composition, because an inexpensive device can be used.

[0071]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. The parts in the following examples are based on weight.

Example 1 Preparation of Composition As a compound having an oxetane ring, the following compound (32) having the following two oxetane rings (hereinafter referred to as component A)
100 parts and 4 parts of the following compound (33) (hereinafter referred to as component G) as a photocationic polymerization initiator were stirred and mixed to produce an active energy ray-curable composition for primary coating of optical fibers.

[0073]

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[0074]

[Chemical 33]

The following evaluations were performed on the obtained composition and cured film. The results are shown in Table 2 below.

Evaluation ○ Curability The obtained composition was applied onto a plurality of glass plates using a bar coater so that the coating thickness was 10 μm, to prepare a plurality of test plates. 80W / c for each test plate
m, ultraviolet rays were radiated at different irradiation doses at a position 10 cm from the bottom of the parallel light type high pressure mercury lamp. The irradiation dose at which the applied composition loses its tackiness is determined by the minimum ultraviolet irradiation dose (J / c).
m ² ).

The composition was applied onto a glass plate using an applicator so that the coating thickness would be 250 μm, and the composition was irradiated with ultraviolet rays until the tackiness was lost, using the same apparatus as described above.
A cured film was obtained. This was peeled from the glass plate and the tensile modulus, heat resistance, hydrolysis resistance and water absorption were examined by the methods described below.

Tensile Modulus The tensile modulus (kgf / cm ² ) of the obtained cured film was measured according to JIS K7113.

Heat resistance After the cured film was stored in air at 120 ° C. for 3 days, the tensile modulus was measured in the same manner as above. The measured value was divided by the value before the test. The larger this value is, the better the heat resistance is.

Hydrolysis resistance After the cured film was stored in water at 80 ° C. for 30 days, the tensile elastic modulus was measured in the same manner as above. The measured value was divided by the value before the test. The larger this value is, the better the hydrolysis resistance is.

Water Absorption The water absorption (%) of the obtained cured film was measured according to JIS K7209 (method B). A material with a low water absorption rate has excellent water absorption.

Examples 2 to 7 Active energy ray-curable compositions for primary coating of optical fibers were produced in the same manner as in Example 1 except that the components having the compositions shown in Table 1 were used. The obtained composition and cured film were evaluated in the same manner as in Example 1. Table 2 shows the results.

Comparative Examples 1 to 3 Active energy ray curable compositions for primary coating of optical fibers were produced in the same manner as in Example 1 except that the components having the compositions shown in Table 1 were used. The obtained composition and cured film were evaluated in the same manner as in Example 1. Table 2 shows the results.

[0084]

[Table 1]

In Table 1, each numeral indicates a part. Further, in Table 1, components B to H represent the following compounds.

Component B [compound of formula (34) below having 3 oxetane rings]

[0087]

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Component C [compound of formula (35) below having one oxetane ring]

[0089]

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Component D [compound of formula (36) having two epoxy groups]

[0091]

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Component E [compound of the following formula (37) having two vinyl ether groups]

[0093]

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Component F [compound of formula (38) below having two acryloyl groups]

[0095]

[Chemical 38]

Component H (compound of the formula (39) below, which is a photoradical polymerization initiator)

[0097]

[Chemical Formula 39]

[0098]

[Table 2] 1) Unit: J / cm ² 2) Unit: kgf / cm ²

[0099]

The active energy ray-curable composition for primary coating of optical fibers of the present invention has a fast curing rate, and its cured film has excellent heat resistance, hydrolysis resistance and water absorption resistance, and further has low tensile elasticity. It has a high rate and is extremely highly practical.

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI Technical display location C09D 5/00 PNW C09D 5/00 PNW G02B 6/44 301 G02B 6/44 301A

Claims (4)

[Claims] 1. An active energy ray-curable composition for optical fiber primary coating, comprising a compound having 1 to 4 oxetane rings and a photocationic polymerization initiator. 2. The active energy ray-curable composition for optical fiber primary coating according to claim 1, further comprising a compound having an epoxy group. 3. The active energy ray-curable composition for primary coating of optical fibers according to claim 1 or 2, which further contains a compound having a vinyl ether group. 4. The active energy ray-curable composition for primary coating of optical fibers according to claim 1, 2 or 3, further comprising a compound having a (meth) acryloyl group and a photoradical polymerization initiator.