JPS59114504A - Material for coating optical plastic fiber - Google Patents

Abstract

PURPOSE:To coat a fiber without increasing loss of optical transmission by using a coating material composed essentially of a highly viscous liquid or solid compd. having a polymerizable -C=C- group, adding a reactive diluent to it, hardening them by irradiating of UV rays or electron beams, and giving tensile elastic modulus to a specified value or more. CONSTITUTION:An optical plastic fiber is coated with a solvent-free type material composed essentially of a highly viscous liquid or solid compd. having polymerizable -C=C- groups, such as polyester acrylate, diluted with a reactive agent, such as ethylene glycol di(meth)acrylate, copolymerizable with said compd. and hardenable by irradiation of UV rays or electron beams. They are hardened with said radiation to give 1,000-30,000kg/cm<2> tensile elastic modulus to the coating material. Since the optical fiber is not damaged by the heat generation during hardening, the optical fiber thus obtained is prevented from increase of optical transmission loss, and creap under load, and enhanced in strength.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a material for coating optical plastic coatings.

BACKGROUND ART Optical plus fibers (hereinafter referred to as optical fibers) such as polystyrene fibers and polymethyl methacrylate are used as optical transmission materials for short distances in automobiles, computers, and the like. This type of optical fiber is usually coated with a wear-resistant thermoplastic + M resin such as polyethylene or nylon in order to strengthen its mechanical properties.

However, since this coating process generally involves melt extrusion molding of polyethylene, nylon, etc. at a temperature of 200°C or higher, there is a risk that the optical fiber itself will thermally decompose, which may cause optical transmission loss. There was a problem of a significant increase.

In addition, the conventional materials described above have a creep phenomenon peculiar to thermo-J plastic resins, and have the problem of not being able to withstand loads for long periods of time.

Therefore, an attempt has been made to solve the above problem by wrapping aromatic organic fibers such as IJ and D-type fibers, glass tape, etc. around the surface of the optical fiber before coating it with the above-mentioned materials. However, in such a method, the coating process tends to be complicated, and there is a concern that the price of the optical fiber will rise.

In view of the above, the present invention provides a new and useful coating material that does not damage the optical fiber even if it is applied directly to the surface of the optical fiber without intervening a high elastic fiber or the like, and can withstand the load for a long time. This is what we are trying to provide.

That is, the present invention is a method of producing a compound which is cured by ultraviolet light, light beam or electron beam, and which has a main phase of an anti-blight liquid or solid compound having a d@ carbon-carbon double bond and a reactive diluent added thereto. The present invention relates to a covering material for optical fibers, which is a water-retaining, solvent-free material, and has a tensile modulus of elasticity after curing of 1,00 kq/c#1 or more.

The main material used in this invention is a high viscosity liquid or solid compound having a polymerizable carbon-carbon bond, and when it is a high viscosity liquid, the viscosity is generally 25°C.
and 1,000 centipoise or more. Typical examples of such main materials include polyester (meth)acrylate, urethane (meth)acrylate, epoxy (meth)acrylate, polyacetal (meth)acrylate, and *-silicone (meth)acrylate, which have an average molecular weight of 500 to 50. .0
It is a (meth)acrylate compound of about 0.00. Other unsaturated polyester resins and acrylic compounds can also be used.

The reactive diluent used in the present invention is used to reduce the viscosity of the recording material or act as a solvent to facilitate the coating operation, and it also reacts and hardens with the recording material itself. It plays the role of a crosslinking agent and becomes one of the components of the optical fiber coating layer. Therefore, various monomers or oligomers can be used as long as they are in a low viscosity liquid form and have a polymerizable carbon-carbon bond in one molecule. The garment used generally has a total weight of about 10 to 50 pieces including the main material.

The fourth material of this invention has the above-mentioned main material and a reactive diluent as essential components, and has the characteristic of being cured by ultraviolet light or electron beam due to the polymerized carbon-carbon double bond contained in both components. However, the tensile modulus after curing is 1.000.
ky/crl or higher. This is because if the tensile modulus is lower than this, the mechanical strength of the optical fiber cannot be sufficiently improved.

In some cases, such a tensile modulus can be achieved by selecting the type of main material, for example by using unsaturated polyester resin, which has a very high tensile modulus as a soil material. In general, the simplest method is to select a reactive diluent that increases the crosslinking density.

Representative examples of such reactive diluents include ethylene glycol di(meth)acrylate, ethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, Polypropylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate,
Examples include polyfunctional acrylates and methacrylates such as 1,6-hexanethiol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and trimethylolpropane tri(meth)acrylate.

By adjusting the usage of these acrylates or methacrylates and using them in combination with monofunctional monomers or oligomers as necessary, a desired tensile strength ratio can be obtained.

Note that the upper limit of the tensile modulus after increasing to 11ψ is usually 3
It is preferable to set it to 0,000 kg/cA. If it becomes too high, the coating layer becomes brittle and the mechanical strength is deteriorated, which is not preferable.

A particularly suitable range of tensile modulus is 1,000 to
It is 10,000 kg/crl.

When the f & coating material of this invention is made into an ultraviolet ray-facilitated type, the photopolymerization initiation of the above-mentioned materials and reactive diluent = 1
is used. Examples of these include benzoin argyl ether, benzophenone, acetophone, and thiogisanone λ. The amount used is usually 0.1 to 10 parts, preferably 1 to 5 parts per 100 parts of soil and reactive diluent. In addition, in the case of electron beam curing type, the above-mentioned heat-setting initiator is not required.

In addition to the above-mentioned components, the coating material of the present invention may optionally contain various modifying resins such as acrylic resin, polyamide resin, polyether, polyuretazo, polyamideimide, silicone resin, phenol 6n=, and epoxy resin. , curing accelerators, organosilicon compounds, surfactants, and other various additives may be added.

The coating material for optical fibers of the present invention having such a composition (components) is characterized by being solvent-free, and its viscosity is generally about 300 to 10,000 centipoise at 25°C. - When actually coating an optical fiber with a metal material, the material is first applied to the surface of the optical fiber and then irradiated with ultraviolet rays or electron beams to polymerize and harden it.

The coating layer after polymerization and curing weighs 1.000 kg/t:r! Since it has a tensile modulus higher than that, the strength of the optical fiber is significantly improved, and the creep phenomenon under load is almost eliminated. Moreover, the above-mentioned polymerization curing is achieved by irradiation with electron beams or ultraviolet rays, which can cause thermal damage to optical fibers caused by melt extrusion of conventional coating materials such as polyethylene and nylon. Increase in optical transmission loss is avoided.

It is also possible to further provide a surface coating layer of polyethylene, nylon, etc. on the cured coating layer formed as described above. In this case, the underlying cured coating layer can prevent thermal damage to the optical fiber during melt extrusion molding of the surface coating 1-. When the cured coating layer becomes too hard, the strength of the optical fiber can be further improved by providing the surface coating layer.

As described in detail above, the coating material of the present invention is a highly elastic material with a high tensile modulus, which increases the optical transmission loss at all because it does not generate heat when exposed. By using this method, the strength of the optical fiber can be greatly improved, and the creep phenomenon under load can be suppressed.

EXAMPLES Below, examples of the present invention will be described in more detail. In addition, in the following, the term ``part'' means ``@Okibe''.

Example 1 80 parts of polyester acrylate (synthesized from phthalate ester of 1,6-hexanediol with a number average molecular weight of 750), 20 parts of trimethylolpropane triacrylate, and 3 parts of benzoinisobutylnithythyl were dissolved and mixed. A coating material with a viscosity of 150.0 centipoise at 25°C was obtained. The tensile modulus of this cured product was 7.000 kg
/crA.

Using this material, diameter 1. After coating a Q mm optical fiber (polymethyl methacrylate fiber) with a thickness of 50 μm, it was irradiated with ultraviolet light (lamp output 2 KW) and cured at a line speed of 1001 n/min.

There was no increase in transmission loss after coating. Also, cart 25
No abnormalities were observed after the creep test at 9.1 o'clock [■].

Example 2 Urethane acrylate (synthesized from polyethylene adipate tolylene diisonanate and 2-hydroxyethyl acrylate, number average molecular number 1,200) 70
part, neopentyl glycol diacrylate +-aOS,
Three parts of penzoin isobutyl ether were dissolved and mixed to obtain a coating material having a viscosity (25° C.) of 9,000 centipoise. The tensile modulus of this h-treated material is 14,000 to 7/cm
Met.

Using this material, it was cured in the same manner as in Example 1 to a thickness of 70 μIn at a linear speed of 150 m/min.

There was no increase in transmission loss after the coating was cured. Ushita/load g2
No abnormalities were observed after a 5ky, 1 hour creep test.

Example 3 70 parts of epoxy acrylate (number average molecule synthesized from bisfutono/L/A diglycidyl ether! 1.000), 30 parts of pentaerythritol triacrylate, and 3 parts of benzoin isobutyl A coating material having a viscosity (25° C.) of 3,500 senvoids was obtained. The tensile modulus of this cured product is 22,500
kg/crl.

Using this material, it was cured in the same manner as in Example 1 to a thickness of 100 μm at a line speed of 100 m/min.

Thereafter, nylon 66 was melt-extruded at 230°C and the outer diameter was 2. Om'm optical fiber cable. There was no increase in transmission loss of the replaced. Also, the load 25 is 7/,
No abnormality detected even after a 1-hour creep test.
It was.

Claims (1)

[Claims] (1) A Jiff solvent-type material that can be cured by ultraviolet rays or electronics and is made of a highly viscous liquid or solid compound having a polymerizable carbon-carbon bond as a base material and a reactive diluent added thereto. The tensile modulus after curing is 1.000.
Coating material H0 for optical plastic fiber characterized by kg/cn1 or more