JPS63308017A - Curable composition - Google Patents

Abstract

PURPOSE:To obtain a curable composition suitable for forming clad of optical fiber, having low refractive index, excellent hardness, flexibility and flexing characteristics, comprising a specific polymerizable unsaturated bond-containing resin and a specific fluoroalkyl (meth)acrylate. CONSTITUTION:A copolymer containing a fluoroalkyl (meth)acrylate [preferably 1H, 1H, 2H, 2H-heptadecafluorodecyl (meth)acrylate] shown by the formula (R is H or methyl; X is H or F; n is 1-12) and a carboxyl group-containing vinyl monomer [e.g. (meth)acrylic acid] is blended with preferably 20-80wt.% polymerizable unsaturated bond-containing resin obtained by esterifying an epoxy group-containing vinyl monomer [e.g. glycidyl (meth)acrylate] or a hydroxyl group-containing vinyl monomer [e.g. hydroxyethyl (meth)acrylate] and preferably 80-20wt.% fluoroalkyl (meth)acrylate shown by the formula to give a curable composition.

Description

[Detailed description of the invention] 1st l upper 2nd yu ± 1 The present invention relates to novel curable compositions.

Conventional technology and its problems Optical fiber technology has developed significantly in recent years, and has been widely used in communication, control,
It has been put into practical use in a wide range of fields such as various optical applied measurements. This technology includes, for example, a system that converts various signals into optical signals, transmits them through optical fibers, converts the transmitted optical signals into target signals, and receives the signals.

Optical fibers consist of a central core and a peripheral cladding. The core usually has a refractive index of about 1.43 to 1.60, is made of stretched glass such as quartz glass, or a plastic fiber such as polymethyl methacrylate, and has a thickness of about 5 to 1000 μm. Often. The cladding is formed around the core and has a thickness of about 3 to 1
It is a transparent coating layer with a refractive index lower than that of the core of about 00μ.

Optical signals propagate through the core while undergoing repeated total reflection at the interface between the core and cladding. At this time, in order to efficiently transmit long distances without leaking the optical signals to the outside, the cladding is The forming material is required to have various properties as described below.

(1) It has a lower refractive index than the core.

(2) Good adhesion to the core.

(3) Good flexibility and bendability.

(4) No crystallinity.

(5) Avoid absorbing light as much as possible.

(6) No thermal decomposition or thermal shrinkage.

(7) Changes in physical properties due to temperature are small.

(8) Excellent water and oil resistance.

(9) Excellent curability and strength.

Conventionally, as a material for forming the cladding, for example, silicone resin, fluorine-containing resin, quartz glass containing boron, fluorine, etc. have been used. However, these materials
None of them have sufficient performance. That is, silicone resin has the disadvantage that it has a high refractive index, is prone to thermal decomposition and thermal contraction, exhibits large changes in physical properties with respect to temperature, and is inferior in hardenability and strength. In addition, as a fluorine-containing resin,
It is known to use non-crosslinked thermoplastic resins such as a copolymer of vinylidene fluoride and tetrafluoroethylene (Japanese Patent Publication No. 53-21660) or a fluoroalkyl methacrylate polymer (Japanese Patent Publication No. 43-8978). The former has residual crystallinity, which causes light to scatter at the interface between the core and cladding, reducing transmission performance, while the latter has insufficient adhesion with the core, flexibility, and bendability. Each has the drawback that physical properties change significantly depending on temperature. Furthermore, silica glass containing boron, fluorine, etc. has the disadvantage that it does not have sufficient flexibility and bendability, and is extremely expensive and economically undesirable.

Means for Solving the Problems The present inventor has conducted extensive research in order to develop a cladding material that eliminates the above-described deficiencies of conventional cladding materials and satisfactorily satisfies all of the above-mentioned required performances. As a result, a composition containing a specific fluorine-containing polymerizable unsaturated resin and a specific fluorine-containing unsaturated monomer is rapidly crosslinked and cured by irradiation with active energy rays such as ultraviolet rays and electron beams. Furthermore, the inventors have discovered that the cured product satisfactorily achieves the above-mentioned required performance, and have completed the present invention.

That is, the present invention provides (a) general formula % formula %) [wherein R represents a methyl group or a hydrogen atom, and X represents a fluorine atom or a hydrogen atom, respectively]. n represents an integer of 1 to 12. ]
A copolymer containing a fluoroalkyl (meth)acrylate represented by and a carboxyl group-containing vinyl monomer,
The main components are a polymerizable unsaturated bond-containing resin obtained by esterifying an epoxy group-containing vinyl monomer or a hydroxyl group-containing vinyl monomer, and (b) a fluoroalkyl (meth)acrylate represented by the above general formula. It concerns a curable composition.

In the present invention, n in the fluoroalkyl (meth)acrylate of the above general formula used in component (a) is 2 to
Particularly preferred is an integer of 8.

Preferred specific examples of the fluoroalkyl (meth)acrylate of the above general formula include IH, 1B, 3H-tetrafluoropropyl (meth)acrylate (n=2), IH
, IH, 5H-octafluoropentyl (meth)acrylate (n = 4), 11'', 1H-)-lysosylfluorohebutyl (meth)acrylate (n = 6>, IH, I
Examples include H,2H,2H-heptadecafluorodecyl (meth)acrylate (n-8), among which 11-1. IH,5H-octafluoropentyl (meth)acrylate, IH,1
1-1,2H,2)-1-heptadecafluorodecyl (
meth)acrylate.

In addition, examples of carboxyl group-containing vinyl single ω substances include (meth)acrylic acid, 2-(meth)acryloyloxyedylsuccinic acid, 2-(meth)acryloyloxyethylmaleic acid, and 2-(meth)acryloyloxyethyl Examples include unsaturated basic acids such as phthalic acid, 2-(meth)acryloyloxyethylhexahydrophthalic acid, and β-carboxyethylate, and at least one of these is used.

The copolymer used in component (a) must use the above-mentioned fluoroalkyl (meth)acrylate and carboxyl group-containing vinyl monomer as monomers, but may also contain other monomers other than these as necessary. Can also be used together. Other monomers include, for example, esterified products of (meth)acrylic acid and monohydric alcohol (1 to 24 carbon atoms), hydroxyalkyl (2 to 8 carbon atoms) esters of (meth)acrylic acid, styrene and its Examples include derivatives, (meth)acrylonitrile, vinyl acetate, vinyl chloride, etc., and one or more of these can be used.

The copolymer used in component (a) is obtained by copolymerizing one or more of the above fluoroalkyl (meth)acrylates and one or more carboxyl group-containing vinyl monomers by a conventional method such as solution polymerization or suspension polymerization. obtained by. From the viewpoint of curability, refractive index, etc. of the composition of the present invention, the ratio of these two components is determined based on the sum of the two components, and the former is 50 to 97.
Weight M% especially 70-95% by weight, #z! person is 50~3 D
%, particularly preferably 30 to 5% by weight. Further, when using other monomers as necessary, it is appropriate to use them in a proportion of 100 parts by weight or less per 100 parts by weight of the above-mentioned two components. The number average molecular weight of these copolymers is about 3,000 to 50,000, especially about 50.
It is preferably in the range of 00 to 300001Ii degrees.

Component (a) used in the present invention is obtained by adding an epoxy group-containing vinyl monomer or a hydroxyl group-containing vinyl monomer to the carboxyl group contained in the above copolymer by esterification. 17 by introducing a polymerizable unsaturated bond into.

Preferred examples of the epoxy group-containing vinyl monomer include acrylic monomers such as glycidyl (meth)acrylate and metaglycidyl (meth)acrylate. Preferred examples of the hydroxyl group-containing vinyl monomer include acrylic spinning wheel omega forms such as hydroxyethyl (meth)acrylate, hydroxypropyl meth)acrylate, and cabrolactan-modified (meth)acrylate.

The amount of addition is not particularly limited, but the degree of unsaturation (the number of equivalents of polymerizable unsaturated bonds per 1,000 number average molecular groups) of the addition reaction product is 0.2 to 3.0, particularly 0.3 to 2.0. It is preferable that the angle be within the range of 0. The number average molecular weight of the resin of component (a), which has been reduced by introducing polymerizable unsaturated bonds, is about 3,100 to 62,000, particularly about 5,100 to 3
Preferably, it is in the range of about 1,000.

In the polymerizable unsaturated bond-containing resin of the component (a), the fluoroalkyl (meth)acrylate lowers the refractive index of the cured product (cured film) together with the following components and maintains the physical strength of the cured product. Has a function. Furthermore, when the content (1) of polymerizable unsaturated bonds is increased within the range of the degree of unsaturation mentioned above, the molecular weight between crosslinks decreases, and the hardness of the cured product can be increased.

Next, as the (oral) component, fluoroalkyl (meth)acrylates represented by the above general formula can be used, and among them, IH. 1H. 2H. 21(,-hebutadecafluorodecyl (meth)acrylate, 1 1-1, I H
．． 5H-octafluoropentyl (meth)acrylate is preferred. Furthermore, in the present invention, a part of the fluoroalkyl (meth)acrylate of component (1), usually about 50% or less, is added to other monomers and oligomers thereof as exemplified in component (a) above. Can be replaced. Examples of the oligomer include polyol (meth)acrylates, polyester (meth)acrylates, polyurethane (meth)acrylates, and silicone (meth)acrylates.
Examples include those having polymerizable unsaturated bonds such as acrylates.

The composition of the present invention is obtained by mixing the above-mentioned (a) component and (b) component, and the composition ratio of these two components is based on the total weight of the two components, and the component (a) is 5% ~95
It is preferable that the content of the component (b) is 2% by weight, especially 20 to 80% by weight, and the component (b) is 95 to 5% by weight, especially 80 to 20% by weight. In the composition of the present invention, if the proportion of the component used as a reactive diluent exceeds 95% by weight, the compatibility and mechanical properties of the cured product tend to decrease; on the other hand, 5!1! If the amount is less than %, the refractive index tends to decrease and the function as a cladding tends to be impaired, which is not preferable.

The thus obtained curable composition of the present invention rapidly undergoes a crosslinking reaction and is cured by irradiation with active energy rays such as ultraviolet rays and electron beams.

When the composition of the present invention is cured by irradiation with ultraviolet rays, it is preferable to add a photopolymerization initiator to the composition in advance. Examples of the photopolymerization initiator include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin n-butyl ether, benzyl, benzophenone, p-methylbenzophenone, diacetyl, eosin, thionin, Michler's ketone, acetophenone, 2-chlorothioxanthone,
Anthraquinone, chloroanthraquinone, 2-methylanthraquinone, α-hydroxyisobutylphenone, p
-isopropyl-α-hydroxyisobutylphenone,
α, α′-dichloro-4-phenoxyacetophenone,
1-hydroxy-1-cyclohexylacetophenone,
2.2-dimethoxy-2-phenylacetophenone, methylbenzoinformate, 2-methyl-1-[4-
(Methylthio)phenyl-2-morpholinopropene, dichlorothioxanthone, diisobrobyldioxanthone, phenyl disulfide-2-nitrosofluorene, butyroin, anisoin dielether, azobisisobutyronitrile, tetramethylthiuram disulfide, etc. One type or a combination of two or more of these can be used. The photopolymerization initiator M used is per 100 parts by weight of the total of components (a) and (b),
It is generally preferable to set it to about 0.1 to 10 parts.

Furthermore, a photopolymerization accelerator can be used in combination with the initiator for the purpose of promoting the photocrosslinking reaction by the photopolymerization initiator,
Typical examples include tertiary amines such as triethylamine, triethanolamine, and 2-dimethylamineethanol, alkylphosphines such as triphenylphosphine, and thiols such as β-thioglycol. can.

Examples of irradiation sources for curing by ultraviolet irradiation include mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, carbon arcs, metal halide lamps, sunlight, and the like. The atmosphere in which ultraviolet rays are irradiated is preferably air or an inert gas. Moreover, when the atmosphere to be irradiated is air, it is particularly preferable to use a high-pressure mercury lamp as the irradiation source. The amount of ultraviolet rays irradiated is not particularly limited, but is usually 10 to 2000 m.
It is appropriate to set it to about J/12.

Examples of electron beam accelerators used for curing by electron beam irradiation include Cockcroft type, Cockcroft-Walton type, resonant transformer type, transformer type, insulated core transformer type, Dynamidron type, linear filament type, and broadband type. Examples include beam type, area beam type, cathode electronic type, and high frequency type. Further, the irradiation of electron beams is not limited as long as the dose necessary to cure the composition is given, but
Generally about 100 to 2000 keys and about 0.5 to 20M
irradiate with a dose of rad. The atmosphere in which the electron beam is irradiated is
Preferably it is an inert gas.

The curable composition of the present invention is particularly suitable for forming the cladding of optical fibers, in which case the various defects of the conventional cladding materials are eliminated, and furthermore, it fully satisfies all the performances required of the cladding material. It is something to do. That is, for example, when a core made of quartz-based glass or the like is stretched into a thread shape, the composition of the present invention is coated by a method known per se such as line drawing or dip coating, and then irradiated with active energy rays such as ultraviolet rays or electron beams. By rapidly crosslinking and curing the film, a cladding can be easily formed.

This cladding fully satisfies all of the above-mentioned required performances. In particular, in the composition of the present invention, the fluorine atom-containing layer can be adjusted to about 25 to 60% by weight, and thereby the refractive index can be adjusted in the range of about 1.45 to 1.36, so it is easy to make the refractive index low. and therefore more light can be transmitted. In addition, it is hard and has excellent flexibility and bendability, and its physical properties change little due to temperature, so it has characteristics such as improved fixation of the core. Also, NA(
Numerical aperture, defined by the formula NI N2. Here, N1 represents the refractive index of the core, and N2 represents the refractive index of the cladding. ) can be obtained, so the acceptance angle becomes large and more light can be taken into the optical fiber.

Therefore, when this is used as a light guide for lighting, decoration, etc., the emitted light becomes stronger and the inner light increases. An image fiber such as a single mirror can brighten the screen, and for communication purposes, the signal strength increases, reducing the exchange loss between light and electricity on the incident side and the light receiving side, so that low-cost replacement elements can be used.

Therefore, an optical fiber having a cladding made of the composition of the present invention can be suitably used in various optical fiber technologies such as communications, image guides, light guides, optical fiber-based measurement, and the like.

Furthermore, since the composition of the present invention has properties of low surface tension and low refractive index, it can be used in water repellents, surface conditioning agents, anti-reflection coatings, piezoelectric elements, UV resists, EB resists, ion exchange membranes, etc. can do. Furthermore, the composition of the present invention has good weather resistance and can be used as an exterior paint.

EXAMPLES Next, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples. In each example, parts and percentages are, in principle, based on weight 1.

Production Example 1 (A) Production of component (A)-I: Put 60 parts of methyl isobutyl ketone and 60 parts of meta-xylene hexafluoride into a 2Q four-bottle flask, raise the temperature to 110°C, and then heat for 1H.
, IH, 2H, 2H-170 parts of hebutadecafluorodecyl acrylate, 20 parts of acrylic acid, and 6 parts of t-butylperoxy-2-ethylhexanoate were added dropwise using a dropping funnel over 3 hours. Aged.

Next, 1 part of t-butylperoxy-2-ethylhexanoate and 13 parts of methyl isobutyl ketone were added dropwise over 1 hour and aged for 7 hours to give a number average molecular weight of about 1400.
A copolymer of 0 was obtained.

To this, 0.1 part of hydroquinone, 1 part of triethylamine
110 parts and 35 parts of glycidyl methacrylate were added.
By keeping it at ℃ for 5 hours, the number average molecular weight is about 15,000
, an acryloyl group-containing resin with an unsaturation degree of 1.1 was obtained. This resin solution was dried under reduced pressure at 40° C. to remove the solvent, resulting in a resin with a solid content of 100%.

(i)-n: In the same way as (i)-I, ill, IH,
A number average molecule m approximately 17, which is obtained by adding 10 parts of glycidyl methacrylate to a copolymer consisting of 190 parts of 5H-octafluoropentyl acrylate and 7.5 parts of methacrylic acid.
000. An acryloyl group-containing resin with an unsaturation degree of 0.4 was synthesized.

This was similarly made into a resin with a solid content of 100%.

(a)-I [[: In the same way as (i)-I, 1H91H
, 80 parts of glycidyl methacrylate was added to a copolymer consisting of 80 parts of 2H,2H-hebutadecafluorodecyl acrylate, 80 parts of 1H,IH,5H-octafluoropentyl acrylate, and 20 parts of acrylic M, with a number average molecular weight of about 19,000, An acryloyl group-containing resin with an unsaturation degree of 1.3 was synthesized. Similarly, the solid content is 100%
made of resin.

(A>-rv:<A)-I Similarly, 1H918,
28,21-1-heptadecafluorodecyl acrylate-1-170 parts and acrylic! To the copolymer consisting of 20 parts, 32 parts of 2-hydroxyethyl methacrylate and p
- By adding 2 parts of toluenesulfonic acid and keeping it at 130°C for 3 hours, the number average molecular m is about 14,500 and the degree of unsaturation is 1.
A 7-acryloyl group-containing resin of 0 was synthesized. This was similarly made into a resin with a solid content of 100%.

Examples 1 to 4 and Comparative Examples 1 to 3 Curable compositions of Examples and Comparative Examples were obtained by mixing the components shown in Table 1 below.

All numerical values in Table 1 above indicate parts. In addition, rUV-7000BJ in Table 1 is a urethane acrylic oligomer specially manufactured by Nippon Gosei Chemical Industry, and has a number average molecular weight of ff130.
00 and the degree of unsaturation is 1.2.

[Darocur-1173J is a photopolymerization initiator manufactured by Merck & Co., which contains α-hydroxyisobutylphenone as an active ingredient. "Irgacure 651" is a photopolymerization initiator manufactured by Ciba Geigy that contains 2,2-dimethoxy-2-phenylacetophenone as an active ingredient. Comparative resin -■ is a resin with a number average molecular weight of about 15,000 obtained by replacing the acrylic acid in (a)-■ with methyl methacrylate-1- and omitting the addition reaction of glycidyl methacrylate.
It is a resin. Comparative resin -■ was the same as (A)-I except that 1t-1,1H,2H,2H-hebutadecafluorodecyl acrylate in (A)-I was replaced with 2-ethylhexyl acrylate. This is a resin with a number average molecular weight of about 14,000 and an unsaturation degree of 1.1.

Next, each of the curable compositions obtained in Examples and Comparative Examples was applied to a quartz glass with a diameter of 150 μm (20° C. using a sodium D line).
A core with a refractive index of 1.458) was line-painted using a die coater to the thickness listed in Table 2, and cured by irradiating it with the amount of ultraviolet rays listed in Table 2 using a high-pressure mercury lamp. Form the cladding and make the optical fiber (q).

Regarding the obtained optical fiber, the refractive index and NA of the cladding, and the transmission [1 loss] at the initial stage and after the cold and heat resistance test were measured. The test methods for the refractive index, transmission loss, and cold/heat resistance test of the cladding are as follows.

Refractive index of 0 cladding: Place the sample on a glass plate at approximately 60μ
The film was coated to a thickness of 1,000 ml, cured by UV irradiation, and then made into a free film and measured using an Atsube refractometer. NA was calculated using this result.

0 transmission loss: An optical fiber slightly longer than 1 km is used, and the light from the laser diode is transmitted through an input element at one end, and the output optical power (PO) is output from the other end.
was measured, a portion of IKm was cut from the output end to the input end, and the output optical power at that point was defined as the input optical power (Pi) from the cut portion to the output end tA, which was calculated using the following equation.

α-1 (10/L)・I OCJ+ o (Po/P
i) Here, α is the transmission loss (dB/Kl), and L
indicates the length of the optical fiber (Km).

0 Cold and heat resistance test: -30℃ for 12 hours, then +80℃
One cycle is to leave it for 12 hours, and this is 20 hours.
This was done by repeating the cycle.

The test results are shown in Table 2.

In addition, regarding Comparative Example 2 in Table 2 above, the test was conducted on a product that was dried at 50° C. for 30 minutes without being irradiated with ultraviolet rays.

Table 2 shows that the optical fiber whose cladding is formed using the curable composition of the present invention has a large NA, so the signal strength is large, the transmission loss is very small, and the transmission loss after the cold and heat resistance test is extremely low. It is clear that long-distance transmission can be carried out efficiently because the amount is small, and that it has excellent performance.

Example 5 IH, 11-1, 2H,
2H-hebutadecafluorodecyl acrylate 5
100 parts of titanium dioxide were mixed and dispersed to obtain a white enamel.

This paint was applied to an acrylic plate to a thickness of 50 μm, and the paint was cured and dried by irradiation with an electron beam of 5 Mrad.

This coating film was subjected to an accelerated weather resistance test using a Sunshine Weather Ometer. It showed very good results in both gloss retention and discoloration.

(that's all)

Claims (1)

[Claims] [1] (a) General formula CH_2=C(R)-COOCX_2(CF_2)_n
X [wherein R represents a methyl group or a hydrogen atom, and X represents a fluorine atom or a hydrogen atom, respectively. n represents an integer of 1 to 12. ] A polymerizable unsaturated bond obtained by esterifying an epoxy group-containing vinyl monomer or a hydroxyl group-containing vinyl monomer to a copolymer containing a fluoroalkyl (meth)acrylate and a carboxyl group-containing vinyl monomer represented by A curable composition containing as main components a containing resin and (b) a fluoroalkyl (meth)acrylate represented by the above general formula.