JP2007219325A - Flame-retardant optical fiber wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-halogen humidity- and heat-resistant flame-retardant optical fiber wire, having proper appearance which is superior in productivity, has minimum protrusion of fibers in its practical use, is superior in adhesiveness with an epoxy resin, can be used even under hot and humid conditions, and will not emit a large amount of smoke or halogen, when it is incinerated. <P>SOLUTION: The optical fiber wire 5 comprises a primary coating layer 2 formed around the circumference of the optical fiber 1, and a secondary coating layer formed around the circumference of the primary coating layer. The secondary coating layer consists of two or more layers, the inner layer 3 of which is composed of a resin composition containing specified amounts of metal hydrate and red phosphorus to a base resin, consisting of a thermoplastic elastomer and/or an ethylene system copolymer, and the outer layer 4 of which is composed of a composition, consisting of specified amounts of metal hydrate and/or triazine derivative compound and/or clay with respect to a base resin, consisting of a polyester elastomer and/or a saponified ethylene vinyl-acetate copolymer. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical fiber, and more particularly to an optical fiber having high flame retardancy, excellent adhesion to an epoxy resin, and usable even under high temperature and high humidity.

As shown in FIG. 3, the optical fiber has a structure in which the outer periphery of the fiber 11 is covered with a primary coating material 12 and the outer periphery of the primary coating material 12 is further covered with a secondary coating material 13. The primary coating layer 12 is generally formed of two or more layers of silicone resin or ultraviolet curable resin. A secondary coating layer 13 is formed by coating the outer periphery with a resin such as polyester elastomer.
The optical fiber is fixed to the connector with an adhesive such as an epoxy resin, and the connector is abutted and joined. However, the optical fiber is not projected by the use environment such as heat cycle. The secondary coating layer and the primary coating layer are sufficiently adhered (see, for example, Patent Document 1 and Patent Document 2).

  Optical fiber strands are usually provided with flame retardancy by using a flame retardant resin composition in the secondary coating layer, but as a flame retardant contained therefor, harmful heavy metals and organophosphorus Currently, halogen compounds are used in addition to compounds. However, when a flame retardant wire in which a secondary coating material is coated with a resin composition containing a halogen-based flame retardant is incinerated, there arises a problem that a large amount of smoke or corrosive gas is generated. For this reason, examination of the technique which expresses a flame retardance without using a halogenated flame retardant is performed actively. As a general flame retardant method, there is a method containing a metal hydrate, but in order to impart high flame retardancy, it must be contained in a large amount, resulting in remarkable mechanical strength and other characteristics. The decline was inevitable.

JP-A-5-157950 JP 2002-162543 A

In particular, in a secondary coating layer used in an optical fiber, a significant decrease in adhesiveness with an epoxy resin used as an adhesive for the primary coating layer or a connector is fatal.
Therefore, it was confirmed that when a sufficient amount of metal hydrate satisfying the flame retardancy was contained in the polyester elastomer of the secondary coating layer, the mechanical strength and adhesive strength of the coating layer were remarkably lowered and could not be used. In that case, it is difficult to maintain the moisture and heat resistance, and it is difficult to maintain the moisture and heat resistance corresponding to 2000 hours at 85 ° C. and 85% shown in the Telcordia standard, which is a typical standard required for communication equipment. Met.

  The present invention has a good appearance, excellent productivity, very little fiber protrusion during actual use, excellent adhesion to epoxy resin, can be used under high temperature and high humidity, and a large amount of smoke and halogen gas during incineration. An object of the present invention is to provide a non-halogen, moisture-resistant, flame-retardant optical fiber that does not generate water.

As a result of intensive studies, the present inventors have found that the secondary coating layer is composed of resin compositions having different compositions in order to achieve the above object.
That is, the present invention
(1) An optical fiber in which a primary coating layer is formed on the outer periphery of a fiber and a secondary coating layer is further formed on the outer periphery of the primary coating layer, and the secondary coating layer includes at least two layers. The inner layer of the secondary coating layer contains 50 to 200 parts by mass of metal hydrate and 0 to 15 parts by mass of red phosphorus with respect to 100 parts by mass of the base resin made of a thermoplastic elastomer and / or an ethylene copolymer. The outermost layer of the secondary coating layer is composed of a resin composition, and metal hydrates 0 to 70 with respect to 100 parts by mass of a base resin made of a polyester elastomer and / or an ethylene-vinyl acetate copolymer saponified product. A flame-retardant optical fiber comprising a resin composition comprising parts by mass, 0 to 60 parts by mass of a triazine derivative compound, and 0 to 30 parts by mass of clay Line,
(2) The flame retardant according to (1), wherein the total mass of the filler in the resin composition constituting the outermost layer is 0 to 70 parts by mass with respect to 100 parts by mass of the base resin of the outermost layer. Optical fiber,
(3) The total mass of the filler in the resin composition constituting the outermost layer is 0 to 45 parts by mass with respect to 100 parts by mass of the base resin of the outermost layer (1) or (2) The flame-retardant optical fiber as described,
(4) The base resin composition of the inner layer is 20 to 70% by mass of a thermoplastic elastomer and 80 to 30% by mass of an ethylene copolymer, wherein any one of (1) to (3) Flame retardant optical fiber,
(5) The metal hydrate in the resin composition constituting the inner layer is 2 or more in mass ratio with respect to the filler in the resin composition constituting the outermost layer (1) to ( 4) The flame-retardant optical fiber according to any one of
(6) The flame retardant optical fiber element according to any one of (1) to (5), wherein the thermoplastic elastomer is at least one selected from a polyester elastomer, a polyurethane elastomer, and a polyamide elastomer. Lines, and
(7) The flame retardant optical fiber according to any one of (1) to (6), wherein a thickness ratio of the inner layer to the outermost layer is 1 to 20.
Is to provide.

In addition to being composed of a non-halogen material, the flame-retardant optical fiber of the present invention can maintain excellent flame retardancy without deteriorating moisture and heat resistance and adhesion to an epoxy resin.
In the present invention, the secondary coating layer is composed of at least two layers, and the base resin of the outermost layer is made of a polyester elastomer and / or a saponified ethylene-vinyl acetate copolymer. The resin composition constituting the inner layer of the secondary coating layer can contain a metal hydrate so that sufficient flame retardancy can be secured using a thermoplastic elastomer and an ethylene copolymer as a base resin. In addition, there is an effect that the mechanical characteristics and moisture and heat resistance as a strand are not impaired. Further, in the present invention, by containing red phosphorus in the inner layer, the content of the metal hydrate can be greatly suppressed, and various properties are improved as compared with the case where only a large amount of the metal hydrate is contained. There is an effect that can be.

Hereinafter, the flame-retardant optical fiber of the present invention will be described in detail.
As shown in FIG. 1, a moisture and heat resistant flame retardant optical fiber 5 according to the present invention includes a primary coating layer 2 formed on the outer periphery of the optical fiber 1 and a secondary coating layer formed of at least two layers on the outer side. It consists of three and four.
First, the primary coating layer 2 formed on the outer periphery of the optical fiber 1 will be described.
The primary coating layer of the flame retardant optical fiber of the present invention is preferably formed of an ultraviolet curable resin. Although it does not specifically limit as ultraviolet curable resin, For example, polyether type, polyester type, an epoxy type, and a polybutadiene type urethane acrylate can be mentioned.
By using the above-described ultraviolet curable resin, the adhesive strength with the secondary coating layer described later is improved. Therefore, it functions to suppress the protruding amount of the fiber protruding from the end face when using the optical fiber.

Next, the secondary coating layer of the flame retardant optical fiber of the present invention will be described.
The secondary coating layer is composed of at least two layers 3 and 4 coated on the outside of the primary coating layer 2. These can be formed by a conventionally known method, and may be extrusion-coated at the same time, or may be further extrusion-coated after forming a coating layer once.
Among these, the base resin of the resin composition constituting the inner layer 3 of the secondary coating layer is composed of a thermoplastic elastomer and / or an ethylene copolymer. Here, each component will be described.

(1) Thermoplastic Elastomer The thermoplastic elastomer used in the present invention can be used without particular limitation as long as it has a hard segment and a soft segment, and among them, a polyester elastomer, a polyurethane elastomer, and a polyamide elastomer are preferable. Any one of these may be used alone, or two or more may be used in combination. When a thermoplastic elastomer is used for the outermost layer of the secondary coating layer described later, it is particularly preferable to use a polyester elastomer. In that case, it is preferable that a soft segment consists only of polyalkylglycol represented by following General formula (1). This is because when the aliphatic polyester is used as the soft segment, the heat and humidity resistance may be lowered.

  As the hard segment of the polyester elastomer, either a polyalkylene terephthalate represented by the following general formula (2) or a polyalkylene isophthalate represented by the general formula (3) may be used. Both may be included.

  Further, when a polyester elastomer is used as the thermoplastic elastomer for the inner layer of the secondary coating layer, the melting point is preferably 200 ° C. or less. In such a case, the heat and moisture resistance and the workability during wiring are good, and the primary coating layer is less likely to foam when the coating layer is coated. The melting point of the polyester elastomer is preferably 120 ° C to 195 ° C, more preferably 150 ° C to 190 ° C. This is because, if the melting point is too low, the wiring performance may be significantly reduced.

  In the present invention, the base resin component of the inner layer may be composed only of a thermoplastic elastomer, but from the viewpoint of adhesion to the primary coating layer and flame retardancy, the thermoplastic elastomer is preferably 20 to 20 in the resin component. 70 mass%, More preferably, it is good to contain 30-60 mass%.

(2) Ethylene-based copolymer In the present invention, an ethylene-based copolymer is used in addition to the thermoplastic elastomer for the base resin of the resin composition used as the inner layer of the secondary coating layer.
Specific examples of the ethylene copolymer that can be used in the present invention include an ethylene-vinyl acetate copolymer, an ethylene-acrylic acid copolymer, an ethylene-ethyl acrylate copolymer, and an ethylene-methacrylate copolymer. Etc. These may be used alone or in combination of two or more. From the viewpoint of improving flame retardancy, an ethylene-vinyl acetate copolymer is preferred. Further, in order to improve flame retardancy, the content of copolymerized components copolymerized with ethylene (for example, VA content for ethylene-vinyl acetate copolymer, EA content for ethylene-ethyl acrylate copolymer) is 40% or more of the ethylene copolymer is preferable, more preferably 60% or more, and particularly preferably 70% or more.

In the present invention, the resin component of the inner layer may be composed only of an ethylene copolymer, but from the viewpoints of adhesion to the primary coating layer and flame retardancy, the ethylene copolymer is preferably among the resin components. It is good to contain 80-30 mass%, More preferably 70-40 mass%.
For the secondary coating inner layer, a thermoplastic elastomer and / or an ethylene copolymer is used as a base resin. The thermoplastic elastomer can improve the adhesion strength between the primary coating layer and the secondary coating outermost layer. On the other hand, ethylene-based copolymers can reduce the content of metal hydrates contained in order to exhibit flame retardancy, avoid a significant decrease in mechanical strength, and also have hydrolysis resistance. Can be improved.

(3) Metal Hydrate The inner layer of the secondary coating layer in the present invention contains metal hydrate and red phosphorus with respect to 100 parts by mass of the base resin composed of the thermoplastic elastomer and / or ethylene copolymer. The resin composition is used.
The type of metal hydrate that can be used in the present invention is not particularly limited. For example, aluminum hydroxide, magnesium hydroxide, hydrated aluminum silicate, hydrated magnesium silicate, basic magnesium carbonate, aluminum orthosilicate, Examples thereof include a metal compound having a hydroxyl group or crystal water such as hydrotalcite, which may be used alone or in combination of two or more. Of these metal hydrates, aluminum hydroxide and magnesium hydroxide are preferred.

  The metal hydrate may be untreated or surface-treated. Examples of the aluminum hydroxide that can be used in the present invention include those that have not been surface-treated (Hidilite H42M (trade name, manufactured by Showa Denko), etc.), those that have been surface-treated with fatty acids such as stearic acid and oleic acid (Hijilite) H42S (trade name, manufactured by Showa Denko) and the like. Magnesium hydroxide that can be used in the present invention is a surface-untreated one (Kisuma 5 (trade name, manufactured by Kyowa Chemical Co., Ltd.)), a surface-treated one with a fatty acid such as stearic acid, oleic acid ( Kisuma 5A (trade name, manufactured by Kyowa Chemical Co., Ltd.), phosphate-treated (Kisuma 5J (trade name, manufactured by Kyowa Chemical Co., Ltd.), etc.), silane coupling agent having a vinyl group or epoxy group at the terminal There is a surface-treated product (Kisuma 5L (trade name, manufactured by Kyowa Chemical Co., Ltd.)).

The flame retardant test methods include horizontal flame retardant, inclined flame retardant and vertical flame retardant tests, but when maintaining vertical flame retardant, the content of metal hydrate in the resin composition is It is necessary to set it as 50-200 mass parts with respect to 100 mass parts of base resin of an inner layer, Preferably it is 80-180 mass parts. If the content is too large, mechanical strength and adhesiveness may be reduced, hydrolysis resistance may be deteriorated, and the appearance may be deteriorated. If the content is too small, flame retardancy is problematic.
Moreover, if it is a grade which does not inhibit adhesiveness with an epoxy resin, you may contain a metal hydrate in the outer layer of a secondary coating layer, and in this case, it is 0 with respect to 100 mass parts of resin components which comprise an outer layer. It is preferable to add about 70 parts by mass.

(4) Red phosphorus In the present invention, it is preferable that the inner layer of the secondary coating layer contains red phosphorus as a flame retardant aid. Red phosphorus can be used in combination with a flame retardant such as a metal hydrate, so that the content of metal hydrate can be greatly reduced even with a small amount.
The content of red phosphorus in the present invention is 0 to 15 parts by mass, preferably 3 to 10 parts by mass with respect to 100 parts by mass of the inner layer base resin. This is because if the content of red phosphorus exceeds 15 parts by mass, the mechanical strength is significantly reduced.

(5) Polyester elastomer In the present invention, a polyester elastomer and / or a saponified ethylene-vinyl acetate copolymer is used as a base polymer in the resin composition constituting the outermost layer of the secondary coating layer.
The polyester elastomer in the present invention generally has a structure of an (AB) n-type multi-block copolymer composed of a crystalline (hard) segment A and an amorphous (soft) segment B, and is structurally hard. The segments are polyesters such as polybutylene terephthalate and polybutylene isophthalate, and the soft segment includes two types of polyether types such as polyethylene glycol and polypropylene glycol and polyester types such as aliphatic polyesters, both of which should be used. Can do.

The polyester elastomer used for the outermost layer of the secondary coating layer is not particularly limited for both the hard segment and the soft segment, but it is preferable to use a polyester elastomer consisting only of the general formula (1) as the soft segment. .
Furthermore, the melting point of the polyester elastomer used for the outermost layer of the secondary coating layer can be used without any particular limitation.
In the present invention, the polyester elastomer may be used alone or in combination of two or more. Moreover, you may mix and use the following ethylene-vinyl acetate copolymer saponified material for the outermost layer of a secondary coating layer, There is no limitation in particular in the ratio, It can mix freely.

(6) Saponified ethylene-vinyl acetate copolymer In the present invention, a saponified ethylene-vinyl acetate copolymer in which a part or all of the acetate groups of the vinyl acetate copolymer is substituted with a hydroxyl group is used in the outermost layer. be able to.
In the present invention, the saponified ethylene-vinyl acetate copolymer may be used alone or in combination of two or more. Further, as described above, it may be used by mixing with the above polyester elastomer, and the mixing ratio is not limited and can be freely mixed.

(7) Triazine derivative compound The triazine derivative compound can be contained in the material constituting the outermost layer of the secondary coating layer of the present invention. The particle size of the triazine derivative compound that can be used here is preferably as small as possible. The average particle size is preferably 10 μm or less, more preferably 7 μm or less, and even more preferably 5 μm or less.
Moreover, it does not specifically limit as a triazine derivative compound which can be used by this invention, Cyanuric acid, a melamine, a melamine derivative, a melamine cyanurate compound, etc. are mentioned. For example, as the melamine cyanurate compound, MCA-0, MCA-1 (both are trade names, manufactured by Mitsubishi Chemical Corporation), Chemie
Some are marketed by Linz GmbH and Nissan Chemical Co., Ltd.
Examples of the melamine cyanurate compound surface-treated with a fatty acid and the silane surface-treated melamine cyanurate compound include MC610, MC440, MC640 (all trade names, manufactured by Nissan Chemical Co., Ltd.). It is preferable to use a melamine cyanurate compound that has been surface-treated from the viewpoint of dispersibility in the resin.
Furthermore, as a triazine derivative, STI-300 (trade name, manufactured by Shikoku Kasei Kogyo Co., Ltd.) and the like are marketed.
The melamine cyanurate compound is represented by the following structural formula, for example.

  In the present invention, the resin composition constituting the outermost layer of the secondary coating layer may or may not contain a triazine derivative compound, and its content is 0 to 100 parts by mass of the outermost resin component. 60 parts by mass, preferably 5 to 40 parts by mass. If the amount of the triazine derivative compound is too small, it does not contribute much to the improvement of flame retardancy. However, if the amount is too large, the mechanical strength and adhesive strength are lowered, and the appearance of the fiber strand is markedly deteriorated.

(8) Clay The outermost layer of the secondary coating layer of the present invention can contain clay.
Clay (clay mineral) is a silicate mineral or the like having a layered structure and is a substance having a layered structure formed by laminating a large number of sheets. Among the above sheets, some are tetrahedron sheets formed by bonding a large number of tetrahedrons made of silicic acid in the plane direction, and some are bonded by a large number of octahedrons containing Al, Mg, etc. in the plane direction. It is an octahedron sheet formed as described above. The layered structure of the sheet, the types of elements constituting the sheet, and the like vary depending on the individual clay. In the present invention, among such clays, for example, montmorillonite, saponite, hectorite, beidellite, stevensite, nontronite, vermiculite, halloysite, mica, fluorinated mica, kaolinite, pyrophyllolite, etc. are used. can do. The clay may be natural or synthetic.

  For the resin composition constituting the outer layer of the secondary coating layer of the present invention, an organized clay obtained by organizing clay (clay mineral) with an organic agent may be used. Various onium ions can be used as the organic agent. These various onium ions are primary to quaternary ammonium ions, such as hexyl ammonium ion, octyl ammonium ion, 2-ethylhexyl ammonium ion, dodecyl ammonium ion, lauryl ammonium ion, octadecyl ammonium ion, dioctyl dimethyl ammonium ion, trioctyl ammonium ion. Ions, dioctadecyldimethylammonium ions, trioctylammonium ions, dioctadecyldimethylammonium ions, trioctadecylammonium ions, and the like can be used.

In this invention, content of clay is 0-30 mass parts with respect to 100 mass parts of outermost layer resin components, Preferably it is 3-15 mass parts. If the clay content is too low, the effect as a flame retardant aid will not be exhibited, and if it is too high, the mechanical strength and adhesive strength will be significantly reduced.
Further, in the present invention, by using a melamine cyanurate compound in addition to a metal hydrate as a flame retardant and clay as a flame retardant aid in the outer layer of the secondary coating layer, generation of water due to the metal hydrate, melamine shear The generation of nitrogen gas by the nurate compound and the clay uniformly dispersed in the resin composition play a role of slowing down the burning rate of the resin composition, and thus are considered to have high flame retardancy. In addition, because of this effect, high flame retardancy can be maintained even if the metal hydrate is reduced, so that the mechanical strength, the adhesive strength between the primary coating layer and the epoxy resin are higher than when containing a large amount of metal hydrate. Can be improved.

  In the present invention, the inclusions excluding the base resin in the resin composition are collectively referred to as a filler, and when the inner layer resin composition can maintain sufficient flame retardancy, a filler that is a flame retardant is provided in the outermost layer. Although it is not necessary to contain, when the flame retardancy contained in the inner layer is insufficient to maintain the flame retardancy, the outermost layer is filled with a filler. The total content of the filler is preferably 0 to 70 parts by mass, more preferably 0 to 45 parts by mass with respect to 100 parts by mass of the base resin in the resin composition constituting the outermost layer. And in order to satisfy the flame resistance / moisture and heat resistance effect by the inner layer and the adhesion effect with the epoxy resin by the outermost layer in a balanced manner, the metal hydrate in the resin composition constituting the inner layer is a resin constituting the outermost layer. The mass ratio is 2 or more with respect to the filler in the composition.

  The resin composition forming the coating layer of the present invention has various additives commonly used in electric wires and cables, such as antioxidants, metal deactivators, and flame retardant (auxiliary) agents. In addition, a filler, a lubricant, and the like can be appropriately contained within a range that does not impair the object of the present invention. Further, a resin other than the polyester elastomer can be mixed as long as the characteristics are not impaired. The range in which mixing is possible is not particularly limited, but is generally 30% by mass or less in the base resin.

  Antioxidants include amine-based antioxidants such as 4,4'-dioctyl diphenylamine, N, N'-diphenyl-p-phenylenediamine, 2,2,4-trimethyl-1,2-dihydroquinoline polymer Agents, pentaerythrityl-tetrakis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate), octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate , 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene and other phenolic antioxidants, bis (2-methyl-4- ( 3-n-alkylthiopropionyloxy) -5-t-butylphenyl) sulfide, 2-mercaptobenzimidazole and its zinc salt, pentaerythritol-tetrakis (3-lauryl-thiopropione) Sulfur-based antioxidants such as theft), and the like.

  Metal deactivators include N, N'-bis (3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyl) hydrazine, 3- (N-salicyloyl) amino-1,2,4 -Triazole, 2,2'-oxamidobis- (ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate).

Fillers and other flame retardants include carbon, clay, zinc oxide, tin oxide, titanium oxide, magnesium oxide, molybdenum oxide, antimony trioxide, silicone compounds, quartz, talc, calcium carbonate, magnesium carbonate, white carbon, etc. Is given.
Examples of lubricants include hydrocarbons, fatty acids, fatty acid amides, esters, alcohols, and metal soaps. Among these, wax E, wax OP (both trade names, manufactured by Clariant), etc. Examples include ester-based, alcohol-based, and metal soap-based materials that exhibit both lubricity and external lubricity. However, if these lubricants, antioxidants, and metal deactivators are added too much, the adhesion with the underlying fiber strands will be significantly reduced, causing problems such as protruding fibers during actual use.

  In the present invention, the problem of die scum is solved by adopting a method of simultaneously extruding the inner layer material and the outer layer material as a method of manufacturing an optical fiber. This is because the inner layer material containing a large amount of additives such as metal hydrates due to die scum is extruded while being covered with the outer layer material having relatively less additives. The thickness ratio of the inner layer to the outermost layer is preferably 1 to 20, and preferably 2 to 10 because the flame retardant / moisture and heat resistance effect by the inner layer and the adhesion effect with the epoxy resin by the outermost layer can be satisfied in a balanced manner. .

Examples 1-22 and Comparative Examples 1-9
A polyether-based urethane acrylate UV curable resin (thickness 0.14 mm) was applied to the outer periphery of an optical fiber having a diameter of 0.125 mm, and a primary coating layer was formed by irradiating 300 mJ / cm ³ of UV light. Thereafter, the thicknesses of 0.25 mm to 0.30 mm at an extrusion temperature of 210 ° C. to 260 ° C. with the contents shown in the table for each material described in Tables 1 to 4 (the numerical values in the table are parts by mass). Now, optical fiber strands each having a secondary coating layer composed of two layers of an inner layer and an outer layer were produced.

Each component material shown in the table is as follows.
1) Hytrel 4777 (Product name: Toray DuPont Co., Ltd.)
Polyester elastomer Melting point: 200 ° C
Hard segment: only the general formula (2)
Soft segment: Polyethylene glycol 2) Hytrel 2551 (trade name: Toray DuPont Co., Ltd.)
Polyester elastomer Melting point: 164 ° C
Hard segment: General formula (2) and general formula (3)
Soft segment: Polyethylene glycol 3) Hytrel 4057 (trade name: Toray DuPont Co., Ltd.)
Polyester elastomer Melting point: 163 ° C
Hard segment: General formula (2) and general formula (3)
Soft segment: Polyethylene glycol 4) Mersen H6960 (trade name: Tosoh Corporation)
Saponified ethylene-vinyl acetate copolymer 5) Resamine P-2288 (trade name: Dainichi Seika Kogyo Co., Ltd.)
Polyurethane elastomer 6) Pebax 4033 (trade name: Atofina)
Polyamide elastomer 7) Revaprene 800HV (Brand name: Bayer)
Ethylene-vinyl acetate copolymer
VA content: 80%
8) Kisuma 5A (trade name: Kyowa Chemical Industry Co., Ltd.)
Magnesium hydroxide 9) Hishiguard LP-F (trade name: Nippon Chemical Industry Co., Ltd.)
Red phosphorus 10) Melamine cyanurate MC860 (trade name: Nissan Chemical Industries, Ltd.)
Melamine cyanurate 11) SP33 (trade name: Engelhard)
Calcined clay

Next, each obtained optical fiber was evaluated for the following items. The results are shown in Tables 1 to 4.
(1) Flame retardancy:
The vertical combustion test of UL1581 was conducted on five samples, and the average time (unit: seconds) until the optical fiber strands disappeared was calculated. Within 60 seconds was accepted.
(2) Adhesiveness:
As shown in FIG. 2, the strength (unit: N) at which one end of the optical fiber 5 was embedded in an opening jig 7 with an epoxy resin 6 and the strand was pulled out was measured. An average of five samples was calculated. 10N or more was accepted. Preferably it is 20N, More preferably, it is 30N.
(3) Moist heat resistance:
It was left under 85 ° C. and 85% wet heat for 1000 hours and 2000 hours, wound around a 50 mm mandrel 6 times, and it was confirmed whether or not cracks occurred in the coated part. “X” indicates that a crack was generated after being left for 1000 hours, “◯” indicates that a crack was not generated after being left for 1000 hours, and “◎” indicates that no crack was generated after 2000 hours. "
(4) Overhang:
The optical fiber was cut to 1.00 m, and a heat shock test at −30 ° C./80° C. was performed on the cut line. The number of cycles was 100 cycles, and each holding time was 2 hours.
A case where the protruding amount from the cross section was less than 0.2 mm was indicated as “◯”, and a case where the protrusion amount was 0.2 mm or more was indicated as “x”.

As can be seen from the results in the table, Comparative Example 1 in which the content of the metal hydrate in the inner layer of the secondary coating exceeds 200 parts has a problem with moisture and heat resistance, and Comparative Example 2 with a content of less than 50 parts has a problem with flame retardancy. Produced. Further, Comparative Example 3 in which the content of red phosphorus in the secondary coating inner layer exceeded 15 parts and Comparative Examples 4 to 6 in which the content of each filler in the outer layer exceeded the specified amount also had a problem in heat and moisture resistance. In Comparative Examples 7 to 9 in which the secondary coating layer is composed of only one layer, sufficient adhesiveness was not obtained.
On the other hand, in Examples 1-22, there was no problem in any item and the favorable characteristic was shown as a flame-retardant optical fiber strand.

It is sectional drawing of the optical fiber strand of this invention. It is the schematic which shows the adhesiveness test method. It is sectional drawing of the conventional optical fiber strand.

Explanation of symbols

1. 1. Optical fiber Primary coating layer3. Secondary coating layer (inner layer)
4). Secondary coating layer (outer layer)
5). 5. Optical fiber strand Epoxy resin7. Hole jig

Claims (7)

  An optical fiber in which a primary coating layer is formed on the outer periphery of an optical fiber, and a secondary coating layer is formed on the outer periphery of the primary coating layer, the secondary coating layer comprising at least two layers, The inner layer of the secondary coating layer contains 50 to 200 parts by weight of metal hydrate and 0 to 15 parts by weight of red phosphorus with respect to 100 parts by weight of the base resin made of a thermoplastic elastomer and / or an ethylene copolymer. And the outermost layer of the secondary coating layer is 0 to 70 parts by mass of metal hydrate with respect to 100 parts by mass of the base resin composed of polyester elastomer and / or saponified ethylene-vinyl acetate copolymer. A flame retardant optical fiber comprising a resin composition comprising 0 to 60 parts by mass of a triazine derivative compound and 0 to 30 parts by mass of clay   The flame-retardant optical fiber according to claim 1, wherein the total mass of filler in the resin composition constituting the outermost layer is 0 to 70 parts by mass with respect to 100 parts by mass of the base resin of the outermost layer. Strands.   The flame retardancy according to claim 1 or 2, wherein the total mass of the filler in the resin composition constituting the outermost layer is 0 to 45 parts by mass with respect to 100 parts by mass of the base resin of the outermost layer. Optical fiber strand.   The flame retardant optical fiber according to any one of claims 1 to 3, wherein the base resin composition of the inner layer is 20 to 70% by mass of a thermoplastic elastomer and 80 to 30% by mass of an ethylene copolymer. Strands.   The metal hydrate in the resin composition constituting the inner layer is 2 or more in mass ratio with respect to the filler in the resin composition constituting the outermost layer. A flame-retardant optical fiber according to item 1.   The flame retardant optical fiber according to any one of claims 1 to 5, wherein the thermoplastic elastomer is at least one selected from a polyester elastomer, a polyurethane elastomer, and a polyamide elastomer. The flame retardant optical fiber according to any one of claims 1 to 6, wherein a thickness ratio of the inner layer to the outermost layer is 1 to 20.

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