JPH05255496A - Fluorine-containing polyether di(meth)acrylate and photocurable composition - Google Patents

Abstract

PURPOSE:To provide the subject polymer consisting of a fluorine-contg. polyether di(meth)acrylate with specific molecular structure, low in refractive index, high in elongation, capable of giving cured products suitable as cladding materials for optical fiber, to be used for photocurable compositions etc. CONSTITUTION:A reaction vessel is charged with a fluorine-contg. alkylene glycol of e.g. formula I, fluorine-contg. alkylene oxide of e.g. formula II, fluorine- contg. alkyl glycidyl ether of e.g. formula III, and baron trifluoride-diethyl ether complex, followed by reaction at 70 deg.C for one hour to produce a fluorine- contg. polyetherdiol, which is, in turn, mixed with acrylic acid chloride and triethylamine followed by reaction at 50 deg.C for 30min, and the reaction product is subjected to a silica gel column to carry out separation and purification, thus giving the objective fluorine-contg. polyether di(meth)acrylate of formula IV (R<1> and R<2> are each H or CH3; R<3> is alkyl; Rf<1> is fluoralkyl; Rf<2> is fluoralkyl ether; a, b and c are each 1-100).

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel fluorine-containing polyether di (meth) acrylate and a photocurable composition containing the compound. The photocurable composition of the present invention is
It is suitable for use as a clad material for optical fibers.

[0002]

2. Description of the Related Art Optical fibers are mainly composed of a two-layer structure in which a core material having a high transparency and a high refractive index is combined with a clad material having a relatively low refractive index. Known clad materials include, for example, silicone resins, polyfluoroalkyl methacrylate copolymers, vinylidene fluoride / tetrafluoroethylene copolymers, and the like.

However, the conventional clad material cannot sufficiently meet the recent required performances such as reduction of transmission loss and simplification of connector attachment by the crimping method. For example, a silicone resin is inferior in mechanical strength and oil resistance, a polyfluoroalkylmethacrylate copolymer is excellent in transparency but has a low softening point, and a vinylidene fluoride / tetrafluoroethylene copolymer is
It has drawbacks such as poor transparency.

In addition, the silicone resin before curing has a short pot life, and it is necessary to strictly control the coating speed and the ambient temperature in order to uniformly coat the core wire (core material). Since the fluoropolymer is coated on the core wire by a melt composite spinning method or a method of coating a melt or a solution, scattering loss due to irregularities in the interface between the core and the clad, fluctuations in the core diameter, microbending, etc. There's a problem. Furthermore, the conventional melt-composite spinning method and coating method have problems that it takes a long time to cure the clad portion and that delamination is likely to occur.

On the other hand, recently, several proposals have been made for a clad material using an ultraviolet curable (photocurable) composition. JP-A-62-250047 discloses (I) a fluorine-containing copolymer, (II) a fluorine-containing (meth) acrylate, (III) a mono (meth) acrylate having an ester moiety substituent having 3 or more carbon atoms, And (IV) A resin composition comprising a polyfunctional monomer having two or more (meth) acryloyl groups is applied to the optical transmission fiber core wire and irradiated with an active energy ray to be cured to produce an optical transmission fiber. A method has been proposed.

Japanese Unexamined Patent Publication No. 64-62363 discloses that
An optical fiber is obtained by applying an ultraviolet-curable coating material comprising (a) an ethylene-based monoene, (b) an ethylenically unsaturated polyene, and (c) a curing initiator onto a core made of fused silica and irradiating the core with ultraviolet rays to cure the coating. Have been proposed.

JP-A-1-294704 discloses a photocurable composition in which a compound having two or more carbon-carbon double bonds and a photopolymerization initiator are combined without using a monofunctional unsaturated compound. It has been proposed to improve the crosslink density by using a material, improve the mechanical strength and the softening temperature as compared with the conventional one, and to form a clad material in which the swelling amount of water at high temperature is reduced. There is.

Since these photocurable compositions form a crosslinked structure by ultraviolet curing, they have excellent mechanical strength, good adhesion to the core material and good transparency, and improve the production rate of optical fibers. It has advantages such as.

However, these conventional photocurable compositions have a small elongation of the cured product, and therefore, the optical fiber using these as a clad material has a large allowable bending radius, which is a problem in manufacturing or using the optical fiber. It was

The clad material in the optical fiber is required to have a lower refractive index than the core material.
Therefore, a compound containing a fluorine atom is usually contained in the composition. However, if the photocurable composition is composed of only the monomer component, the viscosity of the composition is too low, and it is difficult to uniformly apply the composition to the core wire. On the other hand, a compound having a fluoroalkyl group in the side chain as shown in the following formula (III) becomes a solid substance when the degree of polymerization is large, and is not preferable in the production of optical fibers.

[0011]

[Chemical 4] [In the formula, x: y: z = 1: 8: 1]

[0012]

SUMMARY OF THE INVENTION An object of the present invention is to photocure a clad material having a low refractive index, a large elongation, and excellent adhesion to a core material, mechanical strength and heat resistance. To provide a sex composition. Moreover, the objective of this invention is providing the novel fluorine atom containing compound used as a component of the said photocurable composition.

The inventors of the present invention have conducted extensive studies to achieve the above object, and as a result, have a specific chain containing an ether bond in the main chain and an alkyl group in the side chain and a fluoroalkyl group and a fluoroalkyl ether group. By using fluoropolyether di (meth) acrylate as a component of the photocurable composition, a cured product with a low refractive index and a large elongation was obtained, and it was found that it is suitable as a clad material, and based on this finding, The invention was completed.

[0014]

According to the present invention, the general formula (I) is thus obtained.

[0015]

[Chemical 5] [Wherein, R ¹ and R ² are H or CH ₃ , R ³ is an alkyl group, Rf ¹ is a fluoroalkyl group, Rf ² is a fluoroalkyl ether group, and a, b and c are 1 to It is an integer of 100. ] The fluorine-containing polyether di (meth) acrylate represented by these is provided.

According to the present invention, (A) the fluorine-containing polyether di (meth) acrylate represented by the general formula (I), and (B) the general formula (II).

[0017]

[Chemical 6] [In the formula, R ⁴ and R ⁵ are H or CH ₃ , and Rf is a fluorinated aliphatic group or a fluoroalkyl ether group-containing aliphatic group. ] The photocurable composition characterized by containing the fluoro di (meth) acrylate represented by these, and (C) photoinitiator is provided.

The present invention will be described in detail below. The fluorinated polyether di (meth) acrylate of the present invention is a compound represented by the above general formula (I), has an ether bond in the main chain, and has an alkyl group in the side chain and a fluoroalkyl group or a fluoroalkyl ether group. have.

Examples of the alkyl group (R ³ ) include-
_{CH 3, -C 2 H 5,} -C 3 H 7, and the like -C ₄ H _9. Examples of the fluoroalkyl group or fluoroalkyl ether group (Rf ¹ ) include —CH ₂ C ₈
Examples of F ₁₇ , —CH ₂ C ₆ F ₁₃ , and (Rf ² ) include:
And the like _{-CH 2 OCH 2 C 6 F 13} . R ¹
And R ² are each independently H or CH ₃ .

Each of a, b and c is an integer of 1-100. a is preferably 1 to 50, more preferably 1 to 20. b is preferably 1 to 50, more preferably 1 to 20. c is preferably 1 to 50,
More preferably, it is 1-20. a, b and c are 10
When it exceeds 0, the fluorine-containing polyether di (meth) acrylate has a too high molecular weight, and it becomes difficult to adjust the viscosity even when diluted with a reactive diluent, and it becomes difficult to uniformly coat the core material.

The compound represented by the general formula (I) includes, for example, ethylene glycol having a fluoroalkyl group or a fluoroalkyl ether group as a substituent, ethylene oxide having a fluoroalkyl group or a fluoroalkyl ether group as a substituent, and It can be obtained by reacting alkylene oxide to synthesize a fluorine-containing polyether diol, and then reacting this with (meth) acrylic acid halide.

By the way, the photocurable composition conventionally used as a raw material for the clad material uses alkyl (meth) acrylates or fluoroalkyl (meth) acrylates as the monofunctional or polyfunctional compounds. ,
Those cured products showed a relatively small elongation. On the other hand, a cured product of a polyether (meth) acrylate having an ether bond in the main chain has a relatively large elongation, and therefore a photocurable composition containing the same has a relatively large elongation. give.

On the other hand, the clad material of the optical fiber is required to have a smaller refractive index than the core material, so that the photocurable composition used for the optical material can give a cured product having a low refractive index. is necessary. Therefore, the component contained in the photocurable composition is preferably a compound containing a fluorine atom in the molecule. However, although the polymer represented by the general formula (III) has a fluoroalkyl group in its side chain, it becomes a solid substance when the degree of polymerization becomes high, which is not preferable in the production of optical fibers.

Therefore, in order to obtain a cured product having a large elongation and a low refractive index, fluorine-containing polyether (meth) acrylates are preferable. Further, in order to obtain a cured product having excellent mechanical strength and heat resistance, it is desirable that the compound be a polyfunctional compound having two carbon-carbon double bonds, that is, a fluorine-containing polyether di (meth) acrylate. .. Further, the fluorine-containing polyether di (meth) acrylate does not become a solid matter, or even when it becomes a solid matter, when diluted with a reactive diluent,
It is required that the viscosity be easy to handle and that the cured product have good refractive index and elongation.

In the present invention, a copolymer having an ether bond in the main chain and a fluoroalkyl group or a fluoroalkyl ether group in the side chain is used as in the compound represented by the general formula (I). This has solved the above-mentioned problems such as easy handling, high elongation, and low refractive index.

The photocurable composition of the present invention comprises (A) a fluorine-containing polyether di (meth) acrylate represented by the general formula (I) and (B) a fluorodi (meth) acrylate represented by the general formula (II). , And (C) a photopolymerization initiator.

The fluorodi (meth) acrylate represented by the general formula (II) is added as a reactive diluent for adjusting the viscosity or the refractive index of the photocurable composition. In formula (II), R ⁴ and R ⁵ are each independently H or CH ₃ .

Rf ¹ in the general formula (II) is a fluorinated aliphatic group. Examples of such a fluorinated aliphatic group include various groups represented by the following formula.

[0029]

[Chemical 7] [In formula, c and d are 1-2, e is an integer of 1-6. ]

[0030]

[Chemical 8] [In formula, f is 1-2 and g is an integer of 0-7. Rf ² in the general formula (II) is a fluoroalkyl ether group-containing aliphatic group. Examples of such a fluoroalkyl ether group-containing aliphatic group include various groups represented by the following formula.

[0031]

[Chemical 9] [In formula, h is 1-2, i is 1-2, k is an integer of 0-7. ]

Fluorine-containing polyether di (meth) acrylate represented by (A) general formula (I) and (B) general formula (I)
The usage ratio (weight ratio of A: B) of the fluorodi (meth) acrylate represented by I) is usually 99.9: 0.1-1.
It is 0:90, preferably 90:10 to 20:80.

The (C) photopolymerization initiator used in the present invention is preferably a compound which easily generates a radical upon irradiation with ultraviolet rays. Examples thereof include benzophenone, acetophenone, benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether and benzoin isobutyl. Ether, benzyl dimethyl ketal, α, α'-
Azobisisobutyronitrile, benzoyl peroxide, 1-hydroxycyclohexyl phenyl ketone,
2,2-dimethoxy-2-methyl-1-phenylpropan-1-one and the like can be mentioned.

When the photocurable composition of the present invention is used as a clad material for an ultraviolet optical fiber, among them, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1-phenylpropane-1 are particularly preferable. -On is preferred. The photopolymerization initiator is usually used in a proportion of 0.01 to 10% by weight based on the total amount of the composition.

If desired, the photocurable composition of the present invention comprises a photosensitizer, a coupling agent, a light resistance stabilizer, a colorant, an antifoaming agent, a leveling agent, a solvent for adjusting the viscosity, a surfactant, and a surface. A modifier or the like can be added.

By adding a coupling agent to the photocurable composition of the present invention, the wettability and adhesion between the core and the clad when used as a clad material for an optical fiber can be improved. As the coupling agent,
Various types such as silane type and titanium type can be used, but silane type coupling agents are preferable.

Examples of silane coupling agents are trimethoxyvinylsilane, dimethylvinylmethoxysilane, γ-methacryloxypropyltrimethoxysilane,
3- (N-allyl-N-methacryloyl) aminopropyltrimethoxysilane, diethoxydivinylsilane, dimethoxydivinylsilane, dimethyldimethoxysilane,
Examples thereof include dimethyldiethoxysilane, phenyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glydoxypropyltrimethoxysilane, and γ-acryloxypropylmethyltrimethoxysilane. ..

When the photocurable composition of the present invention is used as a clad material, it has a uniform thickness in the core material and a thickness of 1 to 100 μm.
Since it is applied to a thin wall of m, its viscosity is usually 10
It is preferably 0 to 10000 cps (25 ° C.). The viscosity of the photocurable composition is adjusted within a desired range by adjusting the molecular weight of the compound represented by the general formula (I) and the mixing ratio of the reactive diluent represented by the general formula (II). be able to. Further, a solvent or other monofunctional or polyfunctional compound may be used as a diluent as long as the object of the present invention is not impaired.

Since the photocurable composition of the present invention has a large elongation and a low refractive index, it is particularly suitable as a clad material for an optical fiber. Further, since the photocurable composition of the present invention has a large curing density and excellent mechanical strength and heat resistance, it can be used as a protective film for various base materials other than the clad material.

When the photocurable composition of the present invention is used as a clad material for an optical fiber, it is applied onto a core material made of quartz glass, optical glass or synthetic resin by a die coating method or a spray coating method, It may be cured by irradiating with actinic rays such as ultraviolet rays and electron beams. The irradiation dose can be appropriately determined according to the type and amount of the components contained in the composition.

[0041]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples.

Example 1 The following components were charged in a reaction vessel.

[0043]

[Chemical 10] 24.9 parts by weight

[0044]

[Chemical 11] 60 parts by weight

[0045]

[Chemical 12] 37 parts by weight Butylene oxide 6.4 parts by weight Boron trifluoride diethyl ether complex 0.1 parts by weight After reacting at 70 ° C. for 1 hour, the product is separated and purified by a silica gel column to give a fluorine-containing polyether diol of the following formula. Got

[0046]

[Chemical 13] [However, a is 3, b is 2, and c is 1. ]

Then, 30 parts by weight of the obtained fluorine-containing polyether diol, 4 parts by weight of acrylic acid chloride and 4.5 parts by weight of triethylamine were charged, reacted at 50 ° C. for 30 minutes, and then separated and purified by a silica gel column. A fluorine-containing polyether diacrylate of the following formula was obtained.

[0048]

[Chemical 14] [However, a is 3, b is 2, and c is 1. ]

Example 2 48 parts by weight of the fluorine-containing polyether diacrylate obtained in Example 1,

[0050]

[Chemical 15] 45 parts by weight, 2 parts by weight of trimethoxyvinylsilane, 2-
Hydroxy-2-methyl-1-phenylpropane-1-
5 parts by weight of ON was mixed to prepare a photocurable composition A.

The photocurable composition A thus obtained was applied to a glass plate so as to have a thickness of 100 μm, and then 120 W / cm.
After irradiating with ultraviolet rays using a metal halide lamp to cure and peeling from the glass plate, the cured product was measured for refractive index and elongation at break (measurement method: tensile test). The results are shown in Table 1.
Shown in.

Comparative Example 1 A photocurable composition was prepared in the same manner as in Example 2 except that 48 parts by weight of the polymer represented by the general formula (III) was used instead of 48 parts by weight of the fluorine-containing polyether diacrylate. Prepare the product B, and similarly,
The refractive index and elongation at break of the cured product were measured, and the results are shown in Table 1.

[0053]

[Table 1] As is clear from Table 1, the cured product of the photocurable composition of the present invention has a lower refractive index and a large elongation.

[0054]

The photocurable composition of the present invention has a low refractive index and a large elongation. Therefore, the photocurable composition of the present invention is suitable as a clad material for plastic optical fibers and plastic clad optical fibers. Further, the fluorinated polyether di (meth) acrylate of the present invention is useful as a component of such a photocurable composition.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical indication C08F 220/26 MML 7242-4J 299/02 MRS 7442-4J C08L 71/02 LQC 9167-4J LQE 9167 -4J G02B 6/04 G03F 7/004 521 7/027 501

Claims (2)

[Claims] 1. A compound represented by the general formula (I): [Wherein, R ¹ and R ² are H or CH ₃ , R ³ is an alkyl group, Rf ¹ is a fluoroalkyl group, Rf ² is a fluoroalkyl ether group, and a, b and c are 1 to It is an integer of 100. ] Fluorine-containing polyether di (meth) acrylate represented by these. 2. (A) general formula (I): [Wherein, R ¹ and R ² are H or CH ₃ , R ³ is an alkyl group, Rf ¹ is a fluoroalkyl group, Rf ² is a fluoroalkyl ether group, and a, b and c are 1 to It is an integer of 100. ] Fluorine-containing polyether di (meth) acrylate represented by the following: (B) General formula (II) [In the formula, R ⁴ and R ⁵ are H or CH ₃ , and Rf is a fluorinated aliphatic group or a fluoroalkyl ether group-containing aliphatic group. ] The photocurable composition characterized by containing the fluoro di (meth) acrylate represented by these, and (C) photoinitiator.