JPS62269906A - Optical transmission fiber - Google Patents

Abstract

PURPOSE:To obtain the title fiber having excellent flexibility and anti- environmental capability by composing a core component of a photopolymerized polymer of a photocurable liquid resin contg. silicone poly(meth)acrylate having >=2 (meth)acryloyl groups in one molecule, as a main component, and by composing a sheath component of a specific org. polymer respectively. CONSTITUTION:The core component is the photopolymerized polymer (A) composed of the photocurable liquid resin contg. silicone poly(meth)acrylate having >=2 (meth)acryloyl groups in the one molecule as the main component. The sheath component is composed of the org. polymer (B) which has a refractive index lower than that of the core component by >=0.01 and is substantially transparence and has the good flexibility. The silicone poly(meth)acrylate is preferably composed of a condensate of polymethyl phenyl methoxy siloxane and 2-hydroxy ethyl methacrylate, and has the high refractive index and the high transparence, and gives the core material having he good flexibility and heat-resisting property.

Description

DETAILED DESCRIPTION OF THE INVENTION Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a light transmitting fiber that has excellent flexibility and environmental resistance.

[Prior art]

Conventionally, inorganic glass-based fibers have been known to have excellent optical transmission properties over a wide range of wavelengths, but these fibers have poor processability, are susceptible to bending stress, and are expensive. , optically transmitting fibers based on synthetic resins have been developed. Optical transmitting fibers made of synthetic resin have a core-sheath structure, with a core made of a polymer with a high refractive index and good light transmittance, and a sheath made of a transparent polymer with a lower refractive index. It can be obtained by producing fibers with As a polymer useful as a core component having high light transmittance, an amorphous material is preferable, and polymethyl methacrylate or polystyrene is generally used.

Among these core component polymers, polymethyl methacrylate has excellent transparency, mechanical properties, thermal properties, weather resistance, etc., and is used industrially as a core material for high-performance plastic optical fibers. However, this plastic light transmitting fiber made mainly of polymethyl methacrylate does not have sufficient flexibility, and when the diameter exceeds 1 TIa, it becomes rigid and easy to break, making it suitable for use in light guides etc. that transmit a large amount of light. It cannot exhibit sufficient characteristics in applications that require a large diameter. For this reason, there is a need for the development of flexible optically transmitting fibers with large diameters. In addition, plastic light transmitting fibers mainly made of polymethyl methacrylate have a glass transition temperature of 100°C, so
If the environmental conditions exceed 100° C., they cannot be used at all, and their chemical resistance and hot water resistance are also poor, so the uses of plastic optical fibers are limited.

[Structure of the invention]

Therefore, the present inventors have overcome the drawbacks of conventional plastic light transmitting fibers, and have developed environmental resistance such as flexibility, corrosion resistance, heat resistance, cold resistance, moisture resistance, vibration resistance, radiation resistance, etc. As a result of extensive research into developing an all-plastic optical transmission fiber with significantly improved properties, we have arrived at the present invention.

The present invention uses a photopolymer (A) of a photocurable liquid resin as a core component, the main component of which is a silicone poly(meth)acrylate having two or more (meth)acryloyl groups in one molecule; The light transmitting fiber is characterized in that the sheath component is an organic polymer (B) which has a refractive index lower than the refractive index by 0.01 or more and is substantially transparent and has good flexibility.

Photopolymer (A) used as the core component of the optical transmission fiber of the present invention
) is obtained by photopolymerizing a photocurable liquid resin whose main component is silicone poly(meth)acrylate having two or more (meth)acryloyl groups in one molecule. Silico-boly(meth)acrylate is obtained by subjecting an alkoxy group-containing siloxane resin to a dealcoholization reaction with a hydroxy group-containing (meth)acrylate. Examples of the (meth)acrylate containing 7 hydroxy groups include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and monoepoxy compound (meth)acrylate.
Meth)acrylic acid adducts, etc., and mixtures of two or more of these are used. Silicone poly(meth)acrylate needs to have two or more (meth)acryloyl groups in one molecule. If the number of (meth)acryloyl groups is less than two, it is not preferable because not only the light activity of the resulting photocurable liquid resin decreases (but also the heat resistance of the photopolymer serving as the core component deteriorates).

As the silicone poly(meth)acrylate, for example, a condensate of polymethylphenylmethoxysiloxane and 2-hydroxyethyl (meth)acrylate, a condensate of polymethylmethoxysiloxane and 2-hydroxyalkyl (meth)acrylate, etc. are used. Particularly preferred is a condensate of polymethylphenylmethoxysiloxane and 2-hydroxyethyl methacrylate, which can provide a core material that exhibits a high refractive index and high light transmittance, and has good flexibility, good heat resistance, and good heat resistance.

The photocurable liquid resin used in the present invention may be the silicone poly(meth)acrylate alone, but may also be a monovinyl compound such as an alkyl(meth)acrylate having 1 to 12 carbon atoms, tetrahydrofurfuryl(meth)acrylate, Cyclohexyl (meth)acrylate, phenoxyethyl (meth)acrylate, etc. may be used in combination.

The sheath component used in the present invention needs to be a substantially transparent organic polymer CB) having a refractive index lower by 0.01 or more than the refractive index of the core component polymer. The difference in refractive index is 0
．． If it is less than 0.01, not only will the numerical aperture of the resulting light-transmitting fiber be small, but the transmission loss will be extremely large, and furthermore, if the refractive index of the sheath component is thicker than the refractive index of the core component, all of the light will not be transmitted. .

Examples of the organic polymer CB) used as the sheath component of the light transmitting fiber of the present invention include polytetrafluoroethylene, tetrafluoroethylene/perfluoroalkyl vinyl ether copolymer, tetrafluoroethylene/hexafluoropropylene copolymer, Examples include ethylene-vinyl acetate copolymer, vinyl chloride resin, and silicone resin.

Since the optical transmission fiber of the present invention has excellent flexibility, the diameter of the core can be adjusted to 5 to 6000, which is within the range of conventional optical transmission fibers.
μm and even larger. For example, it is possible to manufacture an extremely thick optical transmission line with a core diameter of about 50 mm.

Although the thickness of the sheath layer is required to be 1 μm or more for the purpose of light emission, the upper limit of the thickness of the sheath layer can be appropriately selected depending on the purpose of use.

In order to reinforce the light transmitting fiber of the present invention, an optical fiber cable can be made by using a tension member of another type of polymer such as polyamide, polyester fiber, polyamide fiber, metal fiber, carbon fiber, etc. in combination.

The optical transmission fiber of the present invention can be produced by, for example, forming a photocurable liquid resin as a core component into a fiber, curing it, and then coating it with a sheath component polymer, or forming a sheath component polymer into a hollow fiber. One method is to shape the fiber, suck or press the core liquid resin into it, and then harden it with light to form a light-transmitting fiber.

"Parts" in the following examples mean "parts by weight."

Example 1 Methoxy group 1 of polymethylphenylmethoxysiloxane
per mole of 2-hydroxyethyl methacrylate 1.
Silicone methacrylate (1
(containing 1243 methacryloyl groups per molecule) was obtained.

0.2 parts of benzoin ethyl ether was mixed and dissolved in 100 parts of this silicone methacrylate to give a viscosity of 620 c.
A liquid photocurable resin of ps (25° C.) was obtained. This liquid photocurable resin was filtered in a clean room using a polytetrafluoroethylene filter with a pore size of 0.1 μm, and then defoamed to prepare a precursor for the bottom portion. This precursor was added to 0.
The UV intensity at 365 nanometers using a chemical lamp of 6 watts/(m") is 0.6 m'J watts/cm2.
Ultraviolet rays were irradiated for 60 minutes under the following conditions. The physical properties of the obtained photopolymer are as follows: refractive index nD1-56, tensile strength 3°5
kg/lyn' and elongation was 45%.

On the other hand, tetrafluoroethylene/hexafluoropropylene y85/15 copolymer (nDl, 34) was heated at 625°C.
The fibers were melt-extruded through a hollow nozzle to obtain hollow fibers with an inner diameter of 1°5 mm and an outer diameter of 2.3 m x φ.

This hollow fiber was cut into 100m lengths, one end was connected to a vacuum tube, and the above-mentioned core base precursor was added at 6kg/Crn2G from the other end.
I pressed it in. After the injection of the core material was completed, ultraviolet rays were irradiated for 40 minutes under the above-mentioned ultraviolet irradiation conditions to complete polymerization and to obtain a light transmitting fiber.

Table 1 shows the transmission loss and flexibility evaluation results at 660 nm for this optically transmitting fiber. This transparency,
Even if the fibers are heated at 180°C for 200 hours, or -
Even after being left at 40°C for 200 hours, the transmission loss remained unchanged.

Examples 2 to 4 Light transmitting fibers were obtained in the same manner as in Example 1 except that silicone poly(meth)acrylate shown in Table 1 was used in place of silicone polymethacrylate. Table 1 also shows the transmission loss and flexibility evaluation results at 660 mm of the obtained optically transmitting fiber.

Comparative Example 1 Methacrylic acid 2 instead of silicone polymethacrylate
A light transmitting fiber was obtained in the same manner as in Example 1 except that epoxy methacrylate derived from 1 mole of bisphenol A-type gepoxy resin with 190 mol of epoxy dipping was used.

The optical transmission loss of the obtained fiber was 1570 dE/km, which was considerably worse than that of Example 1, and it did not transmit any light after the flexibility test.

Comparative Example 2 2 moles of acrylic acid, 1 mole of phthalic anhydride, and 2 moles of neopentyl glycol instead of silicone polymethacrylate
A light transmitting fiber was obtained in the same manner as in Example 1 except that oligoester acrylate synthesized from mole was used.

The optical transmittance of the resulting fiber is 1010 dB/k
The optical transmission performance of Example 1 was 3050 dB/km, which was thicker than that of the fiber (and even after the flexibility test, the optical transmission performance was significantly lowered to 3050 dB/km).

Examples 5 to 8 Light transmitting fibers were obtained in the same manner as in Example 1 except that the hollow fibers of the sheath material were replaced with those shown in Table 2.

Table 2 also shows the transmission loss evaluation results of the optically transmittable fibers obtained.

Table 2

Claims (1)

[Scope of Claims] 1. A photopolymer (A) of a photocurable liquid resin whose main component is silicone poly(meth)acrylate having two or more (meth)acryloyl groups in one molecule as a core component, A light transmitting fiber characterized in that the sheath component is an organic polymer (B) that is substantially transparent and has good flexibility and has a refractive index that is 0.01 or more lower than the refractive index of the core component. 2. The light transmitting fiber according to claim 1, wherein the silicone poly(meth)acrylate is a condensate of polymethylphenylmethoxysiloxane and 2-hydroxyethyl methacrylate.