JPS5955401A - Plastic optical fiber - Google Patents

Abstract

PURPOSE:To enhance light transmission efficiency, by using prescribed resins for a core component and a sheath component, highly purifying the sheath component through a specified method, and improving molecular structural compatibility between the core and the clad. CONSTITUTION:The plastic optical fiber consists of a methyl methacrylate polymer as a core material and a copolymer of methacrylate and fluorinated methacrylate as a sheath component. Dust contained in the monomers of the sheath component are controlled to <=100 particles per 1mm.<3>, and they are block copolymerized in the absence of oxygen in a closed system at <=100 deg.C polymn. temp. so as to produce a copolymer contg. 5-50wt% methacrylate component, and <=0.5wt% remaining monomers, and having 50,000-150,000 weight average mol.wt. Optional methacrylate can be selected in accordance with intended physical properties, such as heat resistance strength, or light transmission efficiency, but methyl methacrylate is the most desirable from the view point of the molecular structural compatibility.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a plastic ossidical fiber that has improved optical transmission efficiency through the use of improved fiber resistance and component resins.

Compared to plastic side Butei Calfiher'ri, K machine glass, especially quartz glass fiber IC, it has excellent flexibility even if it has a J diameter, is lightweight, and can easily be obtained with a number of 1" between surfaces. It is said that the connection loss with the light source is small, and it can be mass-produced manually, making it extremely cheap. It has been applied to the f, 11IIII internal transmission system. However, plastic ossidical fibers have the drawback of being inferior in optical transmission efficiency compared to quartz J-laser fibers, and various technological efforts have been made to improve the efficiency.

Conventionally, the core component resin was comi, air/fi,! Efforts have been made to improve optical transmission efficiency by thoroughly removing , transition metals, colored substances, etc., and achieving high purity. However, the present inventors have found that not only the high purity of the core resin, but also the improvement of the molecular structural compatibility between the core-crat resins and the high purity of the core component resin contribute to the direction of optical transmission efficiency. As a result of intensive studies, we have discovered the profound fact that light transmission efficiency can be dramatically improved by using the sheath component resin as shown in the present invention, and have arrived at the present invention. It is something.

That is, the present invention provides a glass fiber fiber having a methyl methacrylate polymer as a core component and a copolymer of Nisdel tutaacrylate and Nisdel fluorinated methacrylic acid as a core component. The above sheath component resin is mixed with the dust of original 4-I11J.
7 is sealed and heated to +00°C J, 1.'- in substantially no acid barley in a sealed system with 100 pieces or less per t+''.
It undergoes bulk polymerization at a polymerization temperature of
Zoshistenokopudikano L is recommended for use with an amount of 50,000 to 150,000, and a residual monomer of 05 to 60,000 yen or less.
It is fiber. 1; Detailed edition 1 contains J2 details.

The core component methyl methacrylate polymer used in the present invention is methacrylic acid (methacrylate) p, 71 menal and ac 1 depending on the optical transmission efficiency, thermal properties, strength, and other desired properties.
Copolymers of other monomers such as 7-notyl norate may also be used. 10% by weight of other monomers in the copolymer
is desirable. In order to increase the light transmission efficiency of the methyl methacrylate polymer as the core component, it is necessary to prepare the monomer and prepare the cloth in a manner that minimizes dust, impurities, etc. in the final composite. From this point of view, it is preferable to carry out polymerization by bulk polymerization method.

A copolymer of a sheath component tsucrylic acid ester and a fluorinated methacrylic acid ester used in the present invention (d, molecular structure compatible with the core component methyl methacrylate polymer)
From the second point of view, it is necessary to use a polymer having an intermediate concentration of Nisder methacrylate. When using a sheath component resin in which the monomer of Nisdel tuccrylate is used, one unit of the Nisder tuccrylate monomer has a molecular structure of FJ-1 with the core component methyl tsutaacrylate.
It is possible to obtain a plastic ossidical fiber with high mutual molecular structural compatibility, improved core-to-sheath adhesion and adhesion, and excellent light transmission efficiency.

As the tsutsuya acrylate ester used in the resin component of the present invention, any tsuta acrylate ester may be selected depending on heat resistance, strength, light transmission strength, and other desired physical properties. For example, methyl methacrylate may be selected. , ethyl methacrylate, tsutakuri 2-glovir silica, butyl methacrylate, etc. Butyl methacrylate is most preferred from the point of molecular structural compatibility.

The fluorinated Nisdel of methacrylic acid used in the sheath component resin of the present invention typically has the following structural formula: H3 1 cI-i2=c CC00CCH2) n (cF2) X (where n = 1 ~2, m21~10, X=H or F
) They may be used alone or in combination in any proportion depending on heat resistance, strength, optical transmission efficiency, and other desired physical properties.

In the present invention, tutaacrylic acid ester and fluorinated ester of tutaacrylic acid ester have heat resistance, refractive index, strength,
Depending on spinnability, light transmission efficiency, and other desired physical properties,
The proportion of methane 1-norate ester in the final polymer is 5-5
0% by weight, preferably 20 to 30% by weight, and 1% in a closed system in a substantially oxygen-free state.
It is necessary to perform bulk polymerization at a polymerization temperature of 00'C or less.

In other words, in order to improve the light transmission efficiency, it is necessary to substantially eliminate the presence of oxygen so that the final polymer does not deteriorate and cause coloration during polymerization, and at +00'C.
It is necessary to polymerize at the following relatively mild polymerization temperature.

In addition, the raw materials used for polymerization should be purified by distillation etc. to remove dust as much as possible by filtering, etc., and the dust in the raw materials is 100% per 1 mm3.
It is necessary to be lower than the individual.

The polymerization initiator to be used may be any initiator that initiates polymerization at 00'C or below and is resistant to heat. Examples include azobisisobutyronitrile, azobisisovaleronitrile, and benzoyl peroxide. etc. The amount to be used may be within the range possible through proper polymerization control. Any chain transfer agent used in the present invention may be selected as long as it does not have an adverse effect such as coloring on the final polymer. Examples include n-butyl mercaptan, L
-butyl mercaptan, 11-dodecyl mercaptan,
Examples include dotesyl mercaptan.

The amount used is such that the weight average molecular weight of the final polymer is 50,000 to 15.
It should be used within a range of 10,000.

The polymer thus obtained has a refractive index difference between the core and sheath resin,
In view of the balance of light transmission efficiency, spinnability, etc., it is necessary to contain tutaacrylic acid ester in the range of 5 to 50% by weight, and from the point of view of spinnability, the weight average molecular weight must be in the range of 50,000 to 150,000. Furthermore, from the point of view of improving optical transmission efficiency,
Is it necessary to keep it below 0.5% by weight?

Is it better to spin the fibers obtained in this way using the component resins, or to choose any method such as coating or melt-spinning? From an industrial perspective, the melt-spinning method is preferable. .

The plastic optical fiber obtained as described above has dramatically improved optical transmission efficiency and excellent mechanical strength, so it is possible to expand the range of applications for short-distance transmission systems.

The present invention will be explained below with reference to Examples.

The optical transmission efficiency was automatically measured between 400 and 700 nm using an optical fiber loss spectrometer manufactured by Operex, and was expressed in (dB/Km).

Example I 10% by weight of meccrylic acid butyl ester purified by distillation and 90% by weight of a fluorinated ester of lylic acid, purified by distillation of 4IBN 0.1
% by weight, 02% by weight of I]-butylnorcaptan purified by distillation was added, and the mixture was filtered through a Polyflon filter to remove dust, and the dust in the mixture was determined to be less than 100 particles per 1 mm3 by laser beam measurement. After cooling, it is charged into a Galanoa/Nor, and repeatedly frozen and degassed with liquid nitrogen, and then melt-sealed in a substantially oxygen-free state. Heat this at 60°C for 5
After polymerization for a period of time, polymerization was carried out at 90°C for 5 hours to complete the polymerization.

The copolymer methacrylic acid butyl ester obtained in this way is 10% by weight, the weight average molecular weight is 50,000, the remaining monomer is 04% by weight as a sheath component resin, polymethyl methacrylate is used as a core component resin, and is coated using a hot melt coating method.・
・It turned into -. Its optical transmission efficiency was 60 dB/K.

Example 2 30-fold P? The formula was purified by distillation of methyl acrylic acid and 7 (the formula purified by distillation of 10% of the fluorinated ester of acid). M
'L%, distilled V, thus purified 1]-Butyl mercap 2F02% by weight 7Jl] L, This t1 amount was filtered through a polyfluorocarbon filter to remove dust, and the dust in the mixture was removed. The sample is poured into a crow ampoule, and the sample is melt-sealed in a substantially oxygen-free state by repeating freezing and degassing with liquid nitrogen. 6 f
Polymerization was carried out at 1'C for 5116 hours, and then polymerization was carried out at 90C for 5 hours to complete the polymerization.

The copolymer obtained by such V filtration (30% by weight of methacrylic acid methyl ester, total average molecular weight 105.00
0. A fiber was formed by a composite melt spinning method using the residual monomer (045% by weight) as the resin component and methyl polytutyacrylate as the core component resin.

The optical transmission efficiency of this material was 90 dt.

Patent applicant: Makoto Asano, patent attorney, acting on behalf of I Kagaku Kogyo Co., Ltd. −

Claims (5)

[Claims] (1) In plastic optical fibers whose core component is methyl methacrylate polymer and whose sheath component resin is a copolymer of methacrylic acid ester and fluorinated ester of methacrylic acid, the sheath component resin is used to remove dust from the raw materials. Bulk polymerization is carried out at a polymerization temperature of 100 C or less in a closed system with substantially no oxygen, containing 5 to 50% by weight of a methacrylic acid ester component, and having a weight average molecular weight of 50,000 to 50,000. 150,000, a glass optical fiber characterized in that it is used with a residual monomer content of 0.5% by weight or less. (2) The plastic optical fiber according to claim 1, wherein the methacrylic acid ester component is 20 to 30% by weight in the copolymer of the sheath component methacrylic acid ester and fluorinated nysnal of methacrylic acid. (3) The plastic optical fiber according to claim 1, wherein the sheath component is a copolymer of a methacrylic acid ester and a fluorinated ester of methacrylic acid, and the methacrylic acid ester component is methyl methacrylate. (4) In the copolymer of methacrylic acid ester and fluorinated ester of methacrylic acid, the fluorinated ester component of methacrylic acid has the following structural formula (%) (in the formula, n-=1 to 2, The glass optical fiber according to claim 1, wherein m = I to I O5X = H or F. (5) In a copolymer of a methacrylic acid ester component and a fluorinated ester of methacrylic acid, the fluorinated ester component of methacrylic acid is the following? A mixture of l'7+ formula (I■3 CI (2=C ■ C0Q(CI2)n(,CF2)mX (in the formula, n, ITI, and X are the same as above) becomes!1', 'l'8'l: Claim 1
Flastinok original Budeikarufubu Ino-- as described in the section.