JPS61186906A - Plastic optical fiber - Google Patents

Abstract

PURPOSE:To improve a fiexibility, a mechanical strength and a light permeability of the titled fiber by using an acrylic elastomer having a specific light permeability as a core material, and by using a fluorine-contg. polymer or a silicone polymer having a lower refractive index than that of the core material as a clad material. CONSTITUTION:The core material of the optical fiber consists of the acrylic elastomer having the optical permability obtained by cross-linking the copolymer composed of 90-99.9mol.% at least one of monomers of the acrylate monomer having 1-8 C alkyl group or the acrylate monomer having 1-8 C alkoxyalkyl group and 0.1-10mol.% at least one of the monomers capable of cross-linking. The clad material comprises the fluorine-contg. polymer or the silicone polymer having the lower reflective index than that of the core material.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a highly flexible optical fiber made of plastic.

[Conventional technology]

Optical fibers have a fibrous structure in which a core with a high optical refractive index is covered with a cladding with a low optical refractive index, and light entering from the end is completely absorbed at the interface between the core and cladding. It travels while reflecting and transmits light.

Conventional optical fibers made of plastic have a core made of polystyrene resin or alkyl methacrylate resin and a cladding made of fluorine-containing resin, as disclosed in Japanese Patent Publication No. 43-8978. Alkyl methacrylate resin has better light transmittance than polystyrene resin or other transparent resins, and from this point of view it is suitable as a core material.

[Problem that the invention seeks to solve]

Traditionally known plastic optical fibers are in a glass state at room temperature, are not sufficiently flexible and are susceptible to bending and impact, and can crease or crack when bent at a sharp angle. The light is scattered there,
It has the disadvantage of poor light transmittance. Another drawback is that it easily breaks if pulled too hard.

The present invention eliminates these drawbacks of conventional plastic optical fibers and is highly flexible.

The object of the present invention is to provide an optical fiber that has excellent mechanical strength and is not inferior in terms of light transmittance to those made of alkyl methacrylate resin, which is the best known material.

[Means for solving problems]

In order to solve the above problems, the inventors of the present invention have conducted repeated research and have obtained the following knowledge. (2) Acrylate polymers having an alkyl group having 1 to 8 carbon atoms have excellent transparency.

(2) Acrylate polymers having an alkoxyalkyl group having 1 to 8 carbon atoms have excellent transparency. ■Above■・■
The copolymer also has excellent transparency. ■ Monomers with crosslinking properties in the above ■ to ■ 0. An acrylic elastomer obtained by crosslinking a copolymer to which 1 mol % or more is added has excellent flexibility. ■Two or more types of monomers having crosslinking properties in the above ■~■0. An acrylic elastomer obtained by crosslinking a copolymer to which 1 mol % or more is added has excellent flexibility. ■Above■
・■ Acrylic elastomer has crosslinking monomer 10
If it is below Mol%, there is no decrease in transparency.

From the above facts, the core of the optical fiber of the present invention is made of an acrylate monomer having an alkyl group having 1 to 8 carbon atoms or an acrylate monomer having an alkoxyalkyl group having 1 to 8 carbon atoms. At least one monomer 80-99. f1Mol% (main component) and at least one type of monomer among crosslinking monomers 0.1 to 10
A light-transmitting acrylic elastomer is obtained by crosslinking a copolymer with Mol% (crosslinking component).

Further, the cladding is a material having a lower optical refractive index than the core material, such as a fluorine-containing polymer or a silicone polymer.

[Effect]

In contrast to conventional optical fibers, in which linear polymer chains are physically entangled, in the optical fiber of the present invention, the entanglement points of polymer chains are chemically bonded through crosslinks in the acrylic elastomer. ing.

〔Effect of the invention〕

Since the optical fiber of the present invention has a three-dimensional network structure formed by crosslinking chemical bonds, it has excellent flexibility, rubber elasticity, and high tensile strength.

Therefore, even if you bend it at a sharp angle, there will be no reflux with creases, so light will not be scattered, and even if you pull it quite strongly, it will not break.

Furthermore, it is superior in terms of light transmittance compared to conventional optical fibers made of alkyl methacrylate resin.

〔Example〕

Examples of the present invention will be described in detail below.

Example 1. 800 parts by weight (l) of ethyl acrylate as an acrylate monomer having an alkyl group, which is the main component of the core material, purified by distillation after removing the polymerization inhibitor.
ol%) and 30 parts by weight (5.0 Mol%) of acrylic acid, which is a crosslinkable monomer that is a crosslinking component of the core material and has been distilled and purified by removing the polymerization inhibitor, and polymerized. 5 parts by weight of azobisisobutyronitrile (0
, 3 Mol %) is added, and this is subjected to bulk polymerization in a N2 stream. Further, 1% by weight of ethylene glycol diglycidyl ether is added to the total weight as a crosslinking agent to bond the crosslinking components of the core material.Next, this mixture is passed through an extruder to
Extrusion crosslinking is performed while heating to 80°C, and the product is wound onto a bobbin and spun. This is coated with polytrifluoroethyl methacrylate as a cladding material to obtain the desired optical fiber. The optical fiber may be protectively coated with vinyl chloride.

Example 2. The acrylic elastomer used as the core material was the same as in Example 1, vinyl methyl silicone was selected as the cladding material, and an optical fiber was obtained in the same manner.

Example 3. A core material is obtained in the same manner as in Example 1 except that methyl acrylate is selected as the acrylate monomer having an alkyl group. The cladding material was also the same as in Example 1, and an optical fiber was obtained by the same method.

Example 4. As an acrylate monomer having an alkyl group, which is the main component of the core material, 800 parts by weight of methyl acrylate was purified by distillation after removing the polymerization inhibitor as in Example 1.
94.7 Mol%) and 2-hydroxyethyl acrylate monomer after removing the polymerization inhibitor and purifying it by distillation.
0 parts by weight (5.0 Mol%) and 5 parts by weight (0.3 Mol%) of azobisisobutyronitrile as a polymerization initiator.
1%) and bulk polymerize in a N2 stream. Using the obtained acrylic elastomer as a core material and polytrifluoroethyl methacrylate as a cladding material, the core and cladding are simultaneously extruded while being heated to 1506C, and the core and cladding are wound onto a bobbin and spun. Note that the 7-acrylic elastomer of the core material in this example is not crosslinked.

The performance of the optical fibers obtained in Examples 1, 2, 3, and 4 is compared with that of commercially available optical fibers using the following table.

In Comparison 1 (commercial product) in the table, the core material is polymethyl methacrylate and the cladding material is a fluorine-containing polymer. Comparison 2 (commercial product) has a core material of polystyrene and a cladding material of polymethyl methacrylate. Transmission loss is at wavelength =
85On+s, opening number N, A, = φrotau foil - (nl is the refractive index of the core, n2 is the refractive index of the cladding), ■ is no crack, O is a small crack, Δ is a crack Occurrence, X is rupture.

The above Examples 1, 2, 3, and 4 are representative examples among those tested by the present inventor, and examples that provide substantially the same performance as these examples will be described below.

(a) Regarding the main components of the acrylic elastomer used as the core material ■ Ethyl acrylate as an acrylate monomer having an alkyl group (Example 1, Example 2, Example 4).

In addition to methyl acrylate (Example 3), n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl Acrylates having an alkyl group having 1 to 8 carbon atoms such as acrylate and 2-cyanoethyl acrylate can be used. Among them, ethyl acrylate and n-butyl acrylate are preferred.
Further, some of these 7 acrylate monomers may be combined and copolymerized.

■ Acrylate monomers having an alkoxyalkyl group include methoxymethyl acrylate, methoxymethyl acrylate, 2-methoxyethyl acrylate, 2-
Acrylates having an alkoxyalkyl group having 1 to 8 carbon atoms such as ethoxyethyl acrylate and 2-butoxyethyl acrylate can be used. Among these, 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate are preferred, and some of these flukoxyalkyl acrylate monomers may be combined and copolymerized.

(2) Some of the acrylate monomers having an alkyl group having 1 to 8 carbon atoms and the acrylate monomer having an alkoxyalkyl group having 1 to 8 carbon atoms may be combined and copolymerized.

■ Copolymerize some of the monomers selected from vinyl chloride, vinylidene chloride, acrylonitrile, styrene, vinyl acetate, ethyl vinyl ether, butyl vinyl ether, alkyl methacrylate, and alkoxy methacrylate to the main components of ■ to ■ above. You can also do this.

(b) Regarding the crosslinking component of the acrylic elastomer that becomes the core material, the monomers that have crosslinking properties include: ■vinyl monomer with a carboxyl group, ■vinyl monomer with an epoxy group, and vinyl with a zero-reactivity halogen group. At least one of the following is selected: (1) a diene vinyl monomer, (2) a vinyl monomer having a hydroxyl group, and (2) a vinyl monomer having an amide group. 0.1 to 10 Mol % of the selected crosslinking component monomer is 90 to 99.9% as the main component of the acrylic elastomer described in (a) above.
Copolymerize with 9Mol%. Preferably, the crosslinking component is 1
The crosslinking agent is added depending on the crosslinking reactive groups of the selected crosslinking component. The amount of crosslinking agent is suitably 0.1 to 10% by weight based on the total amount.Depending on the selected crosslinking component, heat crosslinking can be carried out without a crosslinking agent.

(2) Examples of the vinyl monomer having a carboxyl group include acrylic acid (Example 1, Example 2, and Example 3), methacrylic acid, and itaconic acid. In this case, the crosslinking agent may be, for example, polyepoxides (e.g., ethylene glycol diglycidyl ether and l,8-hexanediol diglycidyl ether used in Example 2 and Example 3), polyols (e.g.,
・4-butanediol, 1.1.i)limethylolpropane) are preferable; heat crosslinking without a crosslinking agent may also be used.

(2) Examples of vinyl monomers having epoxy groups include allyl glycidyl ether, glycidyl acrylate, and glycidyl methacrylate. In this case, the crosslinking agent is
For example, polyamines (eg diethylenetriamine, metaphenylenediamine), polycarboxylic acids (eg adipic acid).

Preferred are acid anhydrides (eg pyromellitic anhydride, maleic anhydride), polyamides, and sulfonamides.

(2) Examples of vinyl monomers having a reactive halogen group include 2-chloroethyl vinyl ether and monochlorovinyl acetate. In this case, the crosslinking agent may be, for example, polyamines (eg diethylenetriamine, triethylenetetramine) or polycarbamates (eg hexamethylenediamine carbamate).

■ Examples of diene vinyl monomers include divinylbenzene, piperylene isoprene, pentadiene, vinylcyclohexene, chloroprene butadiene, methylbutadiene, cyclopentadiene, methylpentadiene, ethylene glycol diacrylate, propylene glycol diacrylate, and ethylene. There are glycol dimethacrylate and propylene glycol dimethacrylate.

In this case, the crosslinking agent may be, for example, sulfur, organic peroxides (
(e.g. penzoyl peroxide, dicumyl peroxide), azo compounds (e.g. azobisisobutyronitrile), vinyl compounds (e.g. divinylbenzene, triallyl cyanurate, triallyl isocyanurate)
However, heat crosslinking without a crosslinking agent may be used.

(2) Vinyl monomers having hydroxyl groups include, for example, hydroxyalkyl acrylate (Example 4), hydroxyalkyl methacrylate, hydroxyalkoxy acrylate, and N-methylol acrylic acid amide. in this case,
Crosslinking agents include, for example, polyisocyanates (e.g. hexamethylene diisocyanate, tolylene diisocyanate), polycarbonates (e.g. adipic acid), alkoxymethylmelamines (e.g. methoxymethylmelamine).
Good.

(2) Vinyl monomers having an amide group include, for example, acrylamide and methacrylamide. In this case, the crosslinking agent may be, for example, amine formaldehyde. Heat crosslinking may be performed without a crosslinking agent.

Note that a low molecule or substance (for example, ethyl acetate) that does not reduce the light transmittance may be added to the acrylic elastomer of the core material obtained from the main component (a) and the crosslinking component (b).

(c) Regarding the polymer serving as the cladding material, the difference between the optical refractive index of the cladding material and the optical refractive index of the core material must be at least 3% for practical purposes of optical fibers. When the core material described above is used, the following fluorine-containing polymers or silicone polymers can be used.

■ At least one of vinyl fluoride, vinylidene fluoride, and tetrafluoroethylene as the fluorine-containing polymer
On the other hand, a copolymer with at least 30 mol % or more of hexafluoropropene has a good strength, but a copolymer with less than 30 mol % of hexafluoropropene is crystalline and opaque, making it unsuitable for use as a cladding material.

Further, as the fluorine-containing polymer, a polymer containing at least one of fluorinated acrylic ester and fluorinated methacrylic ester can be used. That is, it is a polymer of the following formula.

Y knee H1-CH3 Silicone can be used. That is, it is a polymer of the following formula.

R1: -CH3, -C2Hs, -R2 knee H1-CH3, -C2Hs R3: -CH3, -C2H5 2≦a<5000 (integer) 0≦a<5000 (integer) ・A (voluntary) procedural amendment in 1 1. Indication of the case 1985 Patent Application No. 27909 2. Name of the invention Plastic optical fiber 3. Person making the amendment Relationship to the case Patent applicant address 1-12-15 Shiba Daimon, Minato-ku, Tokyo Name
Japan Oil Seal Industry Co., Ltd. 4, Agent 160 Address 2-42-13 Mi 90, Kabukicho, Shinjuku-ku, Tokyo. Crosslinking of copolymers or copolymers...
Correct to J.

(o) Hage 5, from line 19 to page 6, delete lines 3 to 3 (from below [Actions] to above [Effects of the invention]) and insert the following sentence:

Since the optical fiber of the present invention is made of a copolymerized elastomer, it has rubber elasticity and is resistant to bending impact.

Furthermore, by crosslinking this copolymerized elastomer.

Because a three-dimensional network is created by chemical bonds within the molecule,
The rubber elasticity becomes even greater than before crosslinking. ”(c)6
Page, lines 5 and 8 "5119 of bridges. Because there is,"
Delete.

(d) r (Kgf) within the frame of breaking strength on page 8
/mm)J is corrected to r (Kgf1mm2)J.

(to) Page 17, line 9, correct "0≦a<5000 (integer)" to "0≦b<5000 (integer)".

2. Claim 1: At least one monomer of acrylate having an alkyl group having 1 to 8 carbon atoms or an acrylate monomer having a flukoxyalkyl group having 1 to 8 carbon atoms; 90 to 99.9 Mol% of the monomer and 0.1 to 10 Mo of at least one type of monomer having crosslinking properties.
A light-transmissive acrylic elastomer obtained by crosslinking a copolymer with 1% and 1% o4h is used as the core, and a fluorine-containing polymer or silicone polymer having a lower optical refractive index than the core material is used as the cladding. A plastic optical fiber characterized by:

2. Vinyl monomers with carboxyl groups, vinyl monomers with epoxy groups, vinyl monomers with reactive halogen groups, diene vinyl monomers, vinyl monomers with hydroxyl groups, amide groups 2. The plastic optical fiber according to claim 1, wherein at least one of the vinyl monomers is the crosslinking monomer.

3. The fluorine-containing polymer is vinyl fluoride, vinylidene fluoride, tetrafluoroethylene and at least 30 Ma
The plastic optical fiber according to claim 1, which is a copolymer with 1% hexafluoropropene.

4. The fluorine-containing polymer is at least one of acrylic acid fluorinated ester and methacrylic acid fluorinated ester
2. The plastic optical fiber according to claim 1, wherein the plastic optical fiber is a polymer comprising:

5. The plastic optical fiber according to claim 1, wherein the silicone polymer is methyl vinyl silicone, methyl phenyl silicone, or methyl vinyl phenyl silicone.

Claims (1)

[Scope of Claims] 1. At least one monomer of an acrylate monomer having an alkyl group having 1 to 8 carbon atoms or an acrylate monomer having an alkoxyalkyl group having 1 to 8 carbon atoms; 90 to 99.9 Mol% of monomer and 0.1 to 10 Mo of at least one type of monomer having crosslinking property.
A plastic characterized by having a core made of a light-transmitting acrylic elastomer obtained by crosslinking a copolymer with 1% and a cladding made of a fluorine-containing polymer or a silicone polymer having a lower optical refractive index than the core material. optical fiber. 2. Vinyl monomers with carboxyl groups, vinyl monomers with epoxy groups, vinyl monomers with reactive halogen groups, diene vinyl monomers, vinyl monomers with hydroxyl groups, amide groups 2. The plastic optical fiber according to claim 1, wherein at least one of the vinyl monomers is the crosslinking monomer. 3. The fluorine-containing polymer is vinyl fluoride, vinylidene fluoride, tetrafluoroethylene and at least 30Mo
The plastic optical fiber according to claim 1, which is a copolymer with 1% of hexafluoropropene. 4. The fluorine-containing polymer is at least one of acrylic acid fluorinated ester and methacrylic acid fluorinated ester
2. The plastic optical fiber according to claim 1, wherein the plastic optical fiber is a polymer comprising: 5. The plastic optical fiber according to claim 1, wherein the silicone polymer is methyl vinyl silicone, methyl phenyl silicone, or methyl vinyl phenyl silicone.