JPH01106001A - Resin composition for optical fiber sheath - Google Patents

Abstract

PURPOSE:To provide good transparency and mechanical characteristics to the title compsn. and to improve the heat resistance thereof by incorporating a specific crosslinkable oligomer therein. CONSTITUTION:This compsn. contains the crosslinkable oligomer having 1-100wt.% constituting unit expressed by formula I, 0-99wt.% constituting unit expressed by formula II and 0-50wt.% constituting unit consisting of other copolymerizable monomers. In formulas, R<1> and R<2> denote a hydrogen atom or methyl group; B denotes a group-CH2CH2-, etc. In formula II, R<3> denotes a hydrogen atom, fluorine atom or methyl group; A denotes a group (-CH2)-n, etc.; R1 denotes a perfluoroalkyl group of 1-21C; R<4> denotes a hydrogen atom or alkyl group of 1-12C; (n) denotes integer in the range of 1-4; (m) denotes integer in the range of 2-12. The mechanical properties and transparency are thereby improved and the heat resistance is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a resin composition for an optical fiber sheath material that can be used as an optical fiber core, an optical fiber cord, an optical fiber cable, etc.

[Conventional technology]

In an optical fiber having a core-sheath structure, it is important to select a sheath component that takes advantage of the characteristics of the core component. Japanese Patent Publication No. 515-21660 describes an optical fiber whose sheath is made of a copolymer of vinylidene fluoride and tetrafluoroethylene. Vinylidene fluoride copolymers have good adhesion to the core material and are excellent in processability, but they are essentially crystalline polymers and easily crystallize when heated or cooled to grow spherulites. As a result, light passing through the core material is subject to scattering due to the crystallization state of the sheath, resulting in a reduction in light transmission performance.

On the other hand, a polymer containing fluorinated alkyl methacrylate as a main component, such as that disclosed in Japanese Patent Publication No. 56-8321, is poor in quality and has excellent transparency, but it has poor adhesion to the core material and It has poor properties and heat resistance. Furthermore, the α-7 oroacrylate polymer described in JP-A-59-228604 has excellent mechanical properties and transparency;
Although it is said to have heat resistance, it has a strong tendency to thermally decompose when subjected to melt spinning, and has the drawback of easily causing problems such as foaming and coloring during the manufacturing process of optical fibers.

[Means to solve the problem]

The present inventors completed the present invention as a result of research aimed at providing a sheath material with good transparency and mechanical properties and excellent heat resistance.

The present invention is based on the general formula (wherein R1 and R2 are hydrogen atoms or methyl groups, B represents
1 to 100% by weight of the structural unit represented by the general formula % formula % (wherein R3 is a hydrogen atom, a fluorine atom or a methyl group, R,
represents a perfluoroalkyl group having 1 to 21 carbon atoms, where R4 is a hydrogen atom or an alkyl group having 1 to 12 carbon atoms,
n is an integer of 1 to 4, m is an integer of 2 to 12)) and other copolymerizable monomers ([1) are also present in an amount of 0 to 99% by weight. This is a resin composition for an optical fiber sheath material containing 50% by weight of a crosslinkable oligomer.

The resin composition of the present invention contains a fluoroalkyl (meth)acrylate oligomer having a polymerizable unsaturated group as a functional group, and by using this composition, it has low refraction, excellent transparency and mechanical properties. An optical fiber having a crosslinked structure and a sheath material with good heat resistance can be obtained.

The structural unit of formula (■) in the oligomer used in the present invention is:
For example, it can be introduced using the following compounds. C
H2=CHC00CH2CF3, CH2=CHC00C
H2(CF2)2H, CH2=CHC00CH(CF3
)! , CH2=CHC00CH2CH2(CF2)? C
F3, CH2=C(CH8) COOCH, CF8, CH
,=C(CH8) C○0CHtCF', CF'8, C
H,=C(CH,)COOCH,CF2CFHCF3,
CH2=C(CHs)COOCHz(CFJ*H-CH
,=C(CH,) C00CH,CH2(CF,)7C
F,,CH2-C(CHs) CO○CH2CH2N(
CH3) 302(CF2)70F3, CH2=C(C
H3)C00CH2CH2N(CsHJSOz(CF2
)yCFs and other fluoroalkyl (meth)acrylates, and CH2=CHC00CH2CF! , CH2=CF
α-fluoroacrylates such as COOCH2CzF5, etc.

The structural unit of formula I contains a carboxylic acid group in the ester moiety, for example, by copolymerizing the monomer serving as the structural unit of formula (II) and the copolymerizable monomer (III) with acrylic acid or methacrylic acid. It can be introduced by preparing a polymer and reacting this polymer with glycidyl (meth)acrylate (GA) or 2-hydroxyethyl (meth)acrylate (2HEA).

Polymerization of the polymer is carried out in the presence of an initiator such as AIBN for about 30 min.
Preferably, the temperature is 80°C. The subsequent reaction was
It is generally preferred to carry out the reaction in an organic solvent at a temperature of about 60 to 100°C.

Further, as the copolymerizable monomer (III), for example, linear,
Alkyl (meth)acrylates, (meth)acrylic acid esters having a cyclic hydrocarbon group, vinyl monomers capable of forming hydrophilic homopolymers, and the like are used. Chain alkyl (
Examples of meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid.
n-propyl, (meth)acrylic acid-isopropyl, (
#I) 7-n-butyl acrylate, (meth)acrylic acid-
Examples include 2-ethylhexyl. Examples of (meth)acrylic esters having a cyclic hydrocarbon group include phenyl (meth)acrylate, cyclohexyl (meth)acrylate, adamantyl (meth)acrylate, and (yne).
Examples include bornyl (meth)acrylate and tricyclo(5,2゜1,o2.6]-]decar-8-yl (meth)acrylate. Examples of the vinyl monomer that can form a hydrophilic homopolymer include glycidyl ( meth)acrylate, methylglycidyl(meth)acrylate, acrylamide,
2-Hydroxyethyl acrylate), N, N
-dimethylaminoethyl (meth)acrylate and the like.

These copolymerizable monomers (III) are contained in an amount of 0 to 50% by weight.
If it exceeds 50% by weight, the refractive index will become high and it will be difficult to use it as a sheath material.

Examples of the structural unit composed of the copolymerizable monomer (III) are as follows.

-CH2-CR' - In this formula, R5 represents a hydrogen atom or a methyl group, and D represents, for example, an evaalkyl group, a cycloalkyl group, a phenyl group, a hydroxyalkyl group, an alkylaminoalkyl group, or the like.

The oligomer used in the present invention can be produced, for example, by the method described below. Monomer (hereinafter referred to as monomer (I[)] or monomer (II) and ([
The mixture of 1) is copolymerized with (meth)acrylic acid. The amount of these compounds used is based on the weight of the monomer (I[) or (
If and ■): (meth)acrylic acid = 99:1 to 1:9
9 is preferred.

The resulting copolymer is then reacted with GA or 2HEA to obtain a crosslinkable oligomer. GA or 2 HE
A is 0.8 to 1 mole of carboxyl group in the polymer
It is preferable to react at a ratio of 1.5 molar amount. ' The oligomer of the present invention may be used alone or dissolved in a polymerizable monomer for viscosity adjustment, and a polymerization initiator may be added thereto. After coating, the sheath component can be formed by polymerizing with radiation, ultraviolet light, or heating. Examples of the monomer used to adjust the viscosity include copolymerizable monomer Q[l), fluoroalkyl acrylate, and styrene.

The thus formed sheath component coats the core wire surface in an oligomer state, thereby providing good adhesion between the core and sheath, and also has good heat resistance by forming a crosslinkable structure.

Example 1 83 parts by weight of 2,2,2-)lifluoroethyl methacrylate, 12 parts by weight of 1,1,2,2-tetrahydroperfluorodecyl methacrylate, and 5 parts by weight of methacrylic acid, and these monomers A mixture of 0.1% of n-octyl mercaptan and 0.1% of 2.2'-azobisisobutyronitrile was prepared in the absence of oxygen.
Polymerization was carried out for 10 hours in a reactor maintained at 10°C. Next, polymerization was carried out at 120° C. for 2 hours to obtain a polymer (A).

To 100 parts by weight of the polymer (A) thus obtained, 10 parts by weight of 2-hydroxyethyl acrylate, 1 part by weight of hydroquinone, and 0.0 parts by weight of N,N-dimethyllaurylamine.
This was added to 300 parts by weight of a benzene-chloroform mixed solution (volume ratio 1:1) and heated at 80°C for 5 parts by weight.
Allowed time to react. After the reaction, the reaction solution was reprecipitated by adding it to methanol while stirring to obtain a crosslinkable oligomer (B).

Example 2 52 parts by weight of the oligomer obtained in Example 1, 44 parts by weight of trifluoroethyl acrylate, 4 parts by weight of trimethylolpropane triacrylate, and 6 parts by weight of benzyl dimethyl ketal (manufactured by Ciba Geigy, trade name Irgacure 651) as a photopolymerization initiator. Parts by weight were mixed at room temperature to obtain a resin composition (C) for optical fiber sheath material.

This resin composition was cast onto a glass plate to a thickness of 100 μm and tightly covered with a polyester film to prepare a sample. This sample was exposed to light at 80 W/crn for about 1 second using an ultraviolet exposure device equipped with a high-pressure mercury lamp to obtain a cured film. This cured product was a transparent film with a refractive index of 1.416. This film was heated at 150℃ for 10
Transparency did not change after 0 hours of treatment.

A quartz core fiber with an outer diameter of about 200 μm was passed through a coating bath made of the resin composition described above at a speed of about 1 m/sec, and irradiated with ultraviolet light using an ultraviolet exposure device equipped with a high-pressure mercury lamp with an output of 80 w/an. Outer diameter 300
A μm polymer-clad quartz optical fiber was obtained. The optical transmission loss of this optical fiber at a wavelength of 850 nm is 6
The optical transmission loss was good at dB/km, and the optical transmission loss did not change even after processing at 150° C. for 100 hours.

Examples 3 to 7 The component monomers of polymer (A) and the monomers to be reacted to synthesize the crosslinkable oligomer have the composition shown below,
Crosslinkable oligomer (B) was prepared in the same manner as in Example 1 except for 7.
I got it. An optical fiber resin composition was prepared by mixing these crosslinkable oligomers with the monomer composition shown in the table and the photopolymerization initiator used in Example 2, and a film-like cured product was prepared in the same manner as in Example 2. Obtained. All cured products were transparent. The refractive index of this cured product is also shown in the table.

The abbreviations in the table are as follows.

CH3 3FM: CH2=C-COCH2CF3! IFA
: CH,= CH-COCH2CF3+1 4FA : CH2=CH-C0CH2CF2CF2H
○Cl.

MAA: CH2=C-COH MA: CH,=CH-COH ・11 2HEA: CH,=CH-C0CH, CH20HB
DDA Nibutanediol diacrylate TMPTA
: Trimethylolpropane triacrylate NPOD
A: Neopentyl glycol diacrylate HDDA
:Hexanediol diacrylate Example 8 A polycarbonate core fiber with an outer diameter of 1000 μm was taken through a bath made of the resin composition for optical fiber sheath material of Example 6 at a speed of about 1 m/sec, and an ultraviolet exposure device equipped with a high-pressure mercury lamp was used. An optical fiber with an outer diameter of 1050 μm was obtained by irradiating the fibers at an irradiation energy level of 80 w/cm. This optical fiber had a loss of 900 dB/km at a wavelength of 770 nm. This is 13
The loss after 500 hours at 0°C was 770 nm.
It was good at 905 dB/km at this wavelength.

Comparative example

Claims (1)

[Claims] General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (I) (In the formula, R^1 and R^2 are hydrogen atoms or methyl groups, B is a group -CH_2CH_2-, ▲ Numerical formula, chemical formula, There are tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼)
1 to 100% by weight of the structural unit represented by the general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (II) (In the formula, R^3 is a hydrogen atom, a fluorine atom, or a methyl group, and A is a group ■CH_2■_n , ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼, R_f represents a perfluoroalkyl group having 1 to 21 carbon atoms, where R^4 is a hydrogen atom or a carbon number 1 ~12 alkyl groups, n
is an integer of 1 to 4, m is an integer of 2 to 12) and 0 to 99% by weight of a structural unit consisting of another copolymerizable monomer (III). A resin composition for an optical fiber sheath material containing a crosslinkable oligomer having %.