JPH0819317B2 - Polymer composition and optical fiber using the same as sheath material - Google Patents

Description

The present invention relates to a fluoropolymer composition and an optical fiber having the polymer composition as a sheath material.

[Conventional technology]

As the optical fiber, it is known that both the core and the sheath are made of plastic, the core is made of glass, the sheath is made of the plastic, and the core and the sheath are made of glass. Since it has flexibility and is easy to use, it is important for medium and short-distance information communication and displays.

Physical properties required for the sheath material of the optical fiber are low refractive index, good transparency and heat resistance, high adhesiveness with the core material, high mechanical strength and the like. Tokusho
53-21660 describes an optical fiber having a sheath of a copolymer of vinylidene fluoride and tetrafluoroethylene. The vinylidene fluoride copolymer film has good adhesion to, for example, a methacrylate resin and excellent processability, but is essentially a crystalline polymer and easily crystallizes by heating or cooling. Since spherulites grow, light passing through the core material of an optical fiber with a vinylidene fluoride copolymer as a sheath undergoes light scattering by the spherulites in the sheath layer, which lowers the optical transmission performance of the optical fiber. There are drawbacks. On the other hand, for example, a polymer containing a fluoroalkyl methacrylate as a main component as shown in Japanese Patent Publication No. 56-8321 is essentially an amorphous polymer, and an optical fiber having an amorphous polymer sheath is Although it retains good light transmission properties, it has the drawbacks that the light transmission properties tend to deteriorate due to poor adhesion between the sheath layer and the core material, and its workability and heat resistance are insufficient.

[Problems to be solved by the invention]

As described above, the conventional optical fiber sheath material has advantages and disadvantages, and each has its own points to be improved. The object of the present invention is to provide a fluoropolymer composition which satisfies the environmental resistance such as heat resistance and thermal decomposition resistance, and the good workability required when using an optical fiber, and the practical characteristics such as bending resistance, and the like. An object of the present invention is to provide an optical fiber having excellent optical transmission characteristics with a sheath.

[Means for solving problems]

The present invention relates to a comonomer selected from perfluoro-2,2-dimethyl-1,3-dioxole and ethylene, tetrafluoroethylene, chlorotrifluoroethylene, CF ₂ = CFOCF ₃ (hereinafter referred to as an ethylenically unsaturated monomer. 99.99 to 60% by weight of the non-crystalline polymer (I) and an aliphatic hydrocarbon residue, an alicyclic hydrocarbon residue or an aromatic hydrocarbon residue, with some or all of the hydrogen atoms being fluorine. fluorinated hydrocarbon residues and -OH was replaced by an atom, -SR ¹ (R ¹ is C ₁ -C ₅ - alkyl group), - COOH, -SO -, - SO 2 -, - CONH -, - COO -CO
-, -CONHCO-, -COO-, -CN, -NCO, -CO-, -SO
_{-, - NH 2, -SO 3} H, -NHNH 2, -CONH 2, -CH = CH 2, -
^{CH = CH -, (R 1} O) 3 SiO- (R 1 is C ₁ -C ₅ - alkyl group) compound having a functional group in the molecule selected from (II) 0.01 to
And 40% by weight. Polymer (I)
A composition consisting of 99.9 to 95% by weight and 0.1 to 5% by weight of compound (II) is particularly preferred.

The copolymer (I) of perfluoro-2,2-dimethyl-1,3-dioxole of the present invention and at least one ethylenically unsaturated monomer is, for example, described in US Pat. No. 3,978,030.
It can be produced by the method described in JP-A-58-38707.

To produce the copolymer (I), perfluoro-2,2
It is preferable to use -dimethyl-1,3-dioxole and the ethylenically unsaturated monomer in a ratio of 10 to 80 mol%: 90 to 20 mol%.

The copolymer (I) is a perfluoro-2,2-dimethyl-
It has good heat resistance due to the ring structure of 1,3-dioxole and exhibits a high glass transition temperature. However, when this copolymer (I) is used as a sheath material for an optical fiber, the copolymer (I) has poor adhesion to a transparent polymer used as a core material such as methacrylate resin, polycarbonate, etc., or multi-component glass, quartz glass, etc. It has a difficulty in flexibility as a fiber.

On the other hand, when the compound (II) is added to the copolymer (I), the adhesion to the core material and the flexibility are significantly improved.

The compound (II) having in its molecule a fluorinated hydrocarbon residue containing at least one fluorine atom and a functional group is an aliphatic hydrocarbon residue such as a methyl group, an ethyl group or a propyl group in its structure, cyclobutyl Group, cyclopentyl group, cyclohexyl group and other alicyclic hydrocarbon residues or aromatic hydrocarbon residues in which some or all of the hydrogen atoms have been replaced by fluorine atoms I have.

-OH, -SR ¹ (R ¹ is _{C 1 to 5} - alkyl group), - COO
_{H, -SO -, - SO 2} -, - CONH -, - COO-CO -, - CONHC
O-, -COO-, -CN, -NCO, -CO-, -HCOO-, -N
_{H 2, -SO 3 H, -NHNH} 2, -CONH 2, -CH = CH 2, -CH = CH
_{^{-, (R 1 O) 3}} SiO- (R 1 is _{C 1 to 5} - alkyl group).

The following compounds are particularly preferable as the compound (II).
C ₆ F ₁₃ CH ₂ CH ₂ OH, C ₉ F ₁₉ CH ₂ OH, C ₁₀ F ₂₁ CH ₂ CH ₂ OH, HOCH ₂ (C
F ₂ ) ₃ CH ₂ OH, C ₆ F ₁₃ COOH, C ₉ F ₁₉ COOH, C ₈ F ₁₇ CH ₂ CH ₂ COOH,
HOOC (CF ₂ ) ₄ COOH, (C ₇ F ₁₅ CO) ₂ O, C ₈ F ₁₇ SO ₂ NHCH ₂ CH ₃ , C ₈
F ₁₇ SO ₂ N (C ₂ H ₅ ) CH ₂ CH ₂ OH, C ₈ F ₁₇ SO ₃ H, C ₆ F ₁₃ CH ₂ CH ₂ SO
₃ H, C ₆ F ₁₃ SH, C ₈ F ₁₇ NCO, C ₈ F ₁₇ COOC ₂ H ₅ , C ₃ F ₇ OCF (CF ₃ ) C
OOCH ₃ , C ₃ F ₇ O 〔CF (CF ₃ ) CF ₂ O) CF (CF ₃ ) COOCH ₃ , CF ₇ O 〔CF
(CF ₃ ) CF ₂ O) ₂ C (CF ₃ ) COOCH ₃ , (C ₅ F ₁₁ ) ₃ N, C ₇ H ₁₅ CH ₂ N
H ₂ , C ₇ F ₁₅ CONH ₂ , C ₆ F ₅ NHNH ₂ , C ₆ F ₅ SH, C ₆ F ₅ COCH ₃ , H ₂ NC
OCF ₂ CF ₂ CONH ₂ , CF ₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₈ F ₁₇ CH ₂ CH ₂ Si (OC
_{H 3) 3, CH 2 =} CHCOOCH 2 CH 2 C 10 F 21, CH 2 = C (CH 3) COOCH 2 CH 2
C ₁₀ F ₂₁ etc.

As the core material of an optical fiber which can use the polymer composition of the present invention as a sheath material, multi-component glass, inorganic material such as quartz glass, polymethylmethacrylate resin, polystyrene resin, polycarbonate resin, poly-4
Examples include transparent organic polymer materials such as methylpentene-1, deuterated polymethylmethacrylate and polystyrene. Among the transparent organic polymer materials, polymethylmethacrylate resins such as polymethylmethacrylate, copolymers containing at least 70% by weight of methylmethacrylate units, and deuterated resins thereof are preferable from the viewpoint of light transmission performance. Examples of the copolymerization component with methyl methacrylate include acrylic acid esters such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate and 2-ethylhexyl acrylate, methacrylic acid such as cyclohexyl methacrylate, benzyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate. Examples thereof include acid esters. As the polymethylmethacrylate resin, for example, those produced by a continuous bulk polymerization method as disclosed in JP-B-53-42260 are preferable. Other formula A polymer comprising 2% by weight or more of a ring structural unit represented by the formula (wherein R represents an alkyl group or a cycloalkyl group) and 98% by weight of a monomer unit containing methyl methacrylate as a main component is used as a core component. You can also

In the case of producing an optical fiber, the sheath material composition of the present invention is preferably dissolved in a fluorine-based solvent, and the core material surface may be coated with the sheath material composition by immersing the core material in this solution. -A sheath composite spinning nozzle may be used to spin the core polymer and simultaneously extrude the sheath component. The optical fiber thus obtained is coated with a protective layer or a coating layer using an organic polymer, if desired, and further, a tension member such as polyester fiber, polyamide fiber, metal fiber or carbon fiber is used in combination to produce an optical fiber core wire. It can also be used as a product such as an optical fiber cord and an optical fiber cable.

[Action]

The fluoropolymer composition of the present invention is excellent in heat resistance, thermal decomposition resistance and adhesion to the core material, and an optical fiber having this fluoropolymer composition as a sheath has remarkably improved environmental resistance and reliability. Can be made.

Example 1. Perfluoro-2,2-dimethyl-1,3-dioxole 68
2 parts by weight of 3,3,3-trifluoropropyltrimethoxysilane was added to 100 parts by weight of a copolymer composed of mol% and 32 mol% of tetrafluoroethylene, and perfluoro (2-butyltetrahydrofuran) (Fluorinate manufactured by 3M) was added.
It was dissolved in FC-75) to prepare a solution having a solid content of 25% by weight.
The solution was applied to the surface of a silica glass fiber having a diameter of 200 μm, and then passed through a hot air oven at 100 ° C. to obtain an optical fiber having an outer diameter of 250 μm and a core-sheath structure.

The optical transmission loss of this optical fiber was 10.5 dB / km at 850 nm (NA = 0.25). When the minimum diameter of the cylinder that does not break when the optical fiber was wound 360 ° around the cylinder with no load was measured, it was possible to wind even a cylinder with a diameter of 4 mm. Moreover, the optical transmission loss increased less than 1 dB / km even after the optical fiber was kept in a constant temperature chamber at 150 ° C for 4000 hours.

Example 2. 3,3,3 perfluoro -2,5,8- trimethyl-3,6,9 trioxadodecanoic methyl dodecanoate ester instead of trifluoropropyl trimethoxy silane C ₃ F ₇ O [CF ( CF ₃ ) CF
₂ O] ₂ CF (CF ₃ ) COOCH ₃ 1.5 parts by weight was added, and an optical fiber was obtained in the same manner as in Example 1 except for the above. When the minimum winding diameter of this optical fiber was measured in the same manner as in Example 1, the diameter was 4 mm.

Comparative Example A copolymer solution was prepared without using 3,3,3-trifluoropropyltrimethoxysilane, and other conditions were the same as in Example 1 to obtain an optical fiber. The minimum winding diameter of this optical fiber is 10 mm, and it breaks when a cylinder smaller than that is used.

Example 3. Perfluoro-2,2-dimethyl-1,3-dioxole 82
Copolymer consisting of mol% and vinylidene fluoride 18 mol% 10
1.5 parts by weight of perfluorocapric acid was added to 0 parts by weight and dissolved in perfluoro (2-butyltetrahydrofuran) to prepare a solution having a solid content of 20% by weight. This solution has a diameter of 97
After being coated on the surface of a core fiber made of 0 μm polycarbonate, it was passed through a hot air drying oven at 100 ° C. to obtain an optical fiber having a diameter of 1000 μm.

The optical transmission loss of this optical fiber is 870 dB / k at 770 nm.
m. When this optical fiber was inserted into a cylinder with a diameter of 10 mm and bent at ± 90 degrees, and repeated bending tests were performed,
The increase in the optical transmission loss after repeating the bending 5000 times is 50
It was below dB / km. This optical fiber in a constant temperature bath at 125 ° C
The increase in optical transmission loss after holding for 2000 hours was less than 100 dB / km, indicating good heat resistance.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G02B 6/00 391 // C08F 234/02 MNW

Claims (2)

[Claims] 1. A non-crystalline polymer of perfluoro-2,2-dimethyl-1,3-dioxole and a comonomer selected from ethylene, tetrafluoroethylene, chlorotrifluoroethylene and CF ₂ ═CFOCF ₃ ( I) 99.99 to 60% by weight and a fluorinated hydrocarbon residue in which a part or all of the hydrogen atoms of an aliphatic hydrocarbon residue, an alicyclic hydrocarbon residue or an aromatic hydrocarbon residue is replaced with a fluorine atom. And --OH, --SR ¹ (R ¹ is C ₁
-C ₅ - alkyl group), - COOH, -SO -, - SO 2 -, - CON
H-, -COO-CO-, -CONHCO-, -COO-, -CN, -NC
O, -CO -, - SO - , - NH 2, -SO 3 H, -NHNH 2, -CON
_{H 2, -CH = CH 2,} -CH = CH -, (R 1 O) 3 SiO- (R 1 is C ₁ -C
_A polymer composition comprising 0.01 to 40% by weight of a compound (II) having in the molecule a functional group selected from ( ₅ -alkyl group). 2. An optical fiber comprising a translucent core and a sheath of the polymer composition according to claim 1.