JP2982979B2 - Water barrier material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-blocking material, and more particularly to a water-blocking material suitably used for preventing water from entering into an optical communication fiber cable.

[0002]

Conventional optical fiber cables, in particular optical fiber cables of the quartz glass system is generally as shown in FIG. 2, a spacer 3 with a slot as the tension member 8 provided as a core in the outermost central portion around its There is an optical fiber ribbon 1 in the slot
Around it there is a jelly 9 filled as water blocking material consists of jacket layer 4 for further covering the aluminum tape 5 and the whole is provided around the Te.

Recently, optical fiber cables are increasing cases to be buried underground, in a conventional water blocking material
Required characteristics of that, that is with a buffer performance and packing ease,
Water running prevention is regarded as important.

Conventionally, as a material for preventing water running, petrolactam-based or polybutene-based jelly has been used as a water-blocking material for cables. However, while the jelly is excellent in preventing water running, it has drawbacks such as poor workability in connecting cables and increase in transmission loss due to microbending at extremely low temperatures.

In order to solve these problems, in recent years, attempts have been made to fill a cable with a polyacrylic acid-based or carboxymethylcellulose-based water-absorbing polymer to prevent water running. As a method of filling these water-absorbing polymers inside the cable, a method of directly filling the water-absorbing polymer powder, a method of blending the water-absorbing polymer powder with a non-water-soluble adhesive such as varnish, and applying it to a support such as paper or cloth. There is known a method of filling the material (Japanese Unexamined Patent Publication No.
2-249117, JP-A-63-26610, etc.). When the water-absorbing polymer is directly filled, the polymer powder is not fixed, so that the polymer powder easily falls off when connecting the cable, and the connection workability is poor.
In addition, there is a possibility that the polymer powder may move in the cable due to inclination, vibration and the like of the cable, and it is difficult to make the polymer powder uniformly exist in the cable for a long period of time. When filling a water-absorbing polymer coated on a support using a water-insoluble adhesive,
Since the water swellability of the water-absorbing polymer is impaired by the adhesive force of the adhesive, the water-absorbing polymer has a problem that the water-absorbing property is reduced and the water running-preventing property is reduced.

[0006] Thus, the water ran preventing property, fiber optic cable water blocking material having combined performance of easiness of operation in cable during production has not been reported at all so far. Here, the water running preventing property refers to the ability to instantaneously absorb and block water that tends to propagate in the longitudinal direction of the cable when the sheath of the optical fiber cable breaks and water enters for some reason. The water running prevention property indicates the water blocking performance. Here, the number of cm that water propagates in 24 hours is represented by a numerical value. The smaller the value, the better the performance. In addition, the coating buffering property refers to an external force reducing effect of protecting the communication cable core from external force on the cable.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a water-blocking material for an optical fiber cable which is excellent in water running prevention, coating buffering properties, etc., and which is excellent in cable formability during cable connection work and cable production. Is to do.

[0008]

The present inventors have Means for Solving the Problems] As a result of extensive studies to solve the above problems, alpha-olefin also
Is a reaction between a vinyl compound and maleic anhydride or a derivative thereof.
Copolymer (hereinafter referred to as maleic anhydride copolymer) and
And acrylic acid or methacrylic acid as the main monomer
From coalescing (hereinafter referred to as (meth) acrylic acid-based polymer)
One or more addition polymer systems selected from the group consisting of
A polymer carboxyl group-containing polymer (hereinafter, carbo
1) selected from the group consisting of a neutralized product (A) obtained by reacting a basic substance with a xyl group-containing polymer ), a polyvalent epoxy compound and a polyvalent amine compound.
The present inventors have found that the above object can be achieved by applying a mixture of a kind or two or more kinds of a crosslinking agent (B) and a polyhydric alcohol (C) to a support and providing a water-blocking material obtained by crosslinking treatment. Completed the invention.

In the above, the α-olefin means a linear or branched unsaturated hydrocarbon having 2 to 12, preferably 2 to 8 carbon atoms, such as ethylene, propylene, butene-1, Butene-2, isobutylene, 1-
Pentene, 2-methyl-1-butene, 1-hexene, 2
-Methyl-1-pentene, 3-methyl-1-pentene,
4-methyl-1-pentene, 2-ethyl-1-butene,
Diisobutylene, 2-methyl-4-dimethyl-1-pentene, 2-methyl-4-dimethyl-2-pentene and the like. Here, isobutylene also includes a mixture containing isobutylene as a main component, for example, a return BB.

The vinyl compound refers to an unsaturated compound copolymerizable with maleic anhydride, for example, an aromatic olefin such as styrene, an unsaturated halogen compound such as vinyl chloride, an unsaturated ester such as vinyl acetate or vinyl propionate. , Unsaturated ethers such as methyl vinyl ether,
Examples include unsaturated nitriles such as acrylonitrile, acrylates, and vinyl alcohol obtained by saponifying vinyl acetate.

These monomers may be used alone,
Also, two or more types may be used in combination. Of these monomers, α-olefins such as ethylene and isobutylene, styrene and methyl vinyl ether are preferably used, but the use of α-olefins, especially isobutylene, is well suited to the purpose of the present invention.

The derivatives of maleic anhydride include maleic acid, maleic esters and the like. The composition ratio between the α-olefin or vinyl compound and maleic anhydride in the maleic anhydride-based copolymer is such that the reaction product (neutralized product) obtained by reacting the produced copolymer with a basic substance is Any amount can be used as long as it is soluble in water. In the case of each copolymer of ethylene, isobutylene, styrene or methyl vinyl ether and maleic anhydride preferably used in the present invention,
Ethylene, isobutylene, styrene or methyl vinyl ether is used in an amount of about 1 to 3 moles, usually about 1 mole, per mole of maleic anhydride.

[0013] The molecular weight of these copolymers, in dimethylformamide solution, and the intrinsic viscosity [eta] measured at 30 ° C.
And usually, 0.1~8 (dl / g), good Mashiku is 0.2
A 5 (dl / g). If the intrinsic viscosity is less than 0.1, the crosslinking is insufficient and the gel strength in the water-swelling state becomes extremely weak.
Problems such as dissolution of part of the coating layer in water
I will. On the other hand, when the intrinsic viscosity is larger than 8, the solution viscosity when it is made into a solution becomes too large, and there is a problem in workability and production.

The above (meth) acrylic acid polymer is a polymer obtained by polymerizing acrylic acid or methacrylic acid. In addition, poly (meth) acrylates, poly (meth) acrylates, Also included are those obtained by hydrolyzing acrylonitrile, poly (meth) acrylamide, and the like . (Meth) may be a small amount copolymerization copolymerizable vinyl compounds in the acrylic acid-based polymer.

The molecular weight of these (meth) acrylic polymers is 0.5 to 10 (dl / g), preferably 1 to 10, as the intrinsic viscosity [η] measured at 30 ° C. in an aqueous solution containing an electrolyte.
8 (dl / g).

Among these carboxyl group-containing polymers, isobutylene is preferred because it has a low viscosity of an aqueous solution, can react with a crosslinking agent at a high concentration, and has excellent durability of the obtained crosslinked product. copolymers of maleic anhydride is most preferred.

These carboxyl group-containing polymers are reacted with a basic substance to form a water-soluble neutralized product. This reaction is performed, for example, by adding a carboxyl group-containing polymer to an aqueous solution of a basic substance and causing the reaction to proceed.

The basic substance used herein is an alkali metal, alkaline earth metal hydroxide, carbonate, phosphate or ammonia or monoamine, and specifically, sodium hydroxide, potassium hydroxide. , Lithium hydroxide, magnesium hydroxide, sodium carbonate, trisodium phosphate, ammonia, methylamine, ethylamine and the like.

The reaction rate of the basic substance with respect to the carboxyl group-containing polymer is determined by the reaction product of the carboxyl group-containing polymer and the basic substance, since the obtained neutralized product must be water-soluble. It is desirable that the sum is 0.2 or more, preferably 0.4 or more. Here, the degree of neutralization is
In the case of a maleic anhydride copolymer, the degree of neutralization becomes 1 when 2 mole equivalents of a basic substance react with 1 mole of maleic anhydride groups in the copolymer, and the (meth) acrylic In the case of an acid-based polymer, the degree of neutralization is 1 when 1 mole equivalent of a basic substance reacts with 1 mole of carboxylic acid in the polymer.

The polyvalent epoxy compound used as the crosslinking agent (B) in the present invention means an epoxy compound having two or more epoxy groups in a molecule, which is soluble in water or has affinity for water. Examples thereof include ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, glycerin diglycidyl ether, and polyethylene glycol diglycidyl ether.
The polyvalent amine compound means a water-soluble polyamine having two or more amino groups in a molecule, and examples thereof include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and Polyethyleneimine having a chain or a branch is exemplified.

The crosslinking agent (B) is usually 0.1 to 10% by weight based on the neutralized product (A) of the carboxyl group-containing polymer,
Preferably, it is used in a ratio of 0.5 to 5% by weight .

Examples of the polyhydric alcohol (C) used as a plasticizer in the present invention include (poly) such as ethylene glycol, diethylene glycol, propylene glycol and similar alkylene glycols, glycerin, diglycerin, triglycerin, and tetraglycerin. There are glycerins and low molecular weight polyethylene glycols. Among them, glycerin is most preferred in view of the plasticizing effect of the neutralized carboxyl group-containing polymer (A) on the crosslinked product by the crosslinking agent (B) and the compatibility with other components.

The amount of the polyhydric alcohol (C) to be added is 10 to 100 with respect to the neutralized product (A) of the carboxyl group-containing polymer.
Preferably it is in the range of weight% .

The polyhydric alcohol (C) appears to have a weak but chemical bond with the carboxyl group-containing polymer, and furthermore, is mixed with each other due to the wettability inherent to the alcohol, and exerts the respective effects, which is important for the present invention. Has a positive effect.

The support used in the present invention is a long-fiber or single-fiber thread, a string, a woven fabric, a knitted fabric, a wet nonwoven fabric, a dry nonwoven fabric, a spunbonded nonwoven fabric, a paper, a film, and the like. Although there is no particular limitation, acrylic synthetic fibers, nylon-based synthetic fibers, polyester-based synthetic fibers and the like are preferred.

The water-blocking material of the present invention is prepared by applying a mixed aqueous solution comprising a neutralized product of a carboxyl group-containing polymer (A), a crosslinking agent (B) and a polyhydric alcohol (C) to an appropriate support surface. After spraying, it is obtained by dry heat treatment. The heat treatment conditions are the carboxyl group-containing polymer used.
Although it depends on the type of the neutralized product (A) and the type of the cross-linking agent (B) and the amount of use thereof, the heat treatment time is usually about 1 minute to 2 hours under a temperature condition of 100 to 200 ° C. It is. If the heat treatment is insufficient, the crosslinking becomes insufficient, and the desired water-absorbing and swelling properties cannot be obtained, which is not suitable for the purpose of the present invention.

In producing the water-blocking material of the present invention, the mixture comprising the components (A), (B) and (C) contains a flame-retardant filler such as aluminum hydroxide. May be.

FIG. 1 is an enlarged sectional view of a slot type optical fiber cable using the water-blocking material of the present invention. This optical fiber cable has a tension member 8 as a core provided at the most central portion, a spacer 3 having a slot therearound, an optical fiber core tape 1 provided at the slot portion, and a water shielding tape 7 for a slot.
And a water-repellent tape 10 provided around the spacer 3 and a cover layer 4 covering the whole. In such a configuration, when a crack occurs in the jacket layer 4 and water infiltrates the optical fiber, the water that has penetrated causes the presser-wound water-impervious tape 6, the slot water-impervious tape 7, and the water-impervious prevention thread. 10 instantaneously absorbs water and swells, keeping water intrusion slightly and preventing further water intrusion for a long time.

Depending on the dimensions of the cable slot and the number of core wires, by increasing the weight of the water-absorbing coat layer of the press-winding water-impervious tape, for example, the slot water-impervious tape and the water-impervious protective yarn can be used. Even if it is omitted, sufficient water barrier performance can be obtained.

The water shielding material of the present invention can be widely applied not only to preventing water running of an optical fiber cable but also to other uses.

For example, sanitary materials such as diapers, napkins,
Thin and compact, it can be used for incontinence pads, breast milk pads , water-absorbing sheets for civil engineering construction, more specifically for various water-blocking materials, dew condensation prevention sheets, water-blocking mats, as well as freshness-keeping, drip-sheet cooling and heat storage materials. And water absorption capacity,
It can be widely used as a material for making products with excellent water blocking ability.

[0032]

The present invention will be described below in more detail with reference to examples.

The water absorption capacity and water running resistance in the examples were measured according to the following measuring methods. (1) water absorption ratio of distilled water or artificial sea water (Hachishu Pharmaceutical Co., Ltd., trade name: Aquamarine) was immersed for 30 minutes at room temperature the sample, the weight after draining for 10 minutes on a nylon cloth of 200 mesh Expressed as an increase factor. (2) Anti-water running property 1) Thread or string for vacant groove Drainage material is spread over a glass tube with an inner diameter of 5 mm over a length of 100 cm.
The glass tube was placed horizontally, and the end of the glass tube was connected to a vertically-standing glass tube having an inner diameter of 10 mm with a rubber tube, and the vertically-standing glass tube was placed 1 m from the horizontally placed glass tube.
Filled with water up to the height, horizontally placed after 24 hours
Penetration length of the water shield water material for glass tubes (water running length) is measured. Those with a short water running length have good water running preventing properties. 2) Holding tape The holding tape is wrapped around a glass rod of 10 mm in outer diameter and 1 m in length in a spiral shape so that it does not overlap and there is no gap, and is inserted into a glass tube having an inner diameter of 12 mm and an outer diameter of 15 mm to be horizontal. every, former and vertically erected inner diameter 10mm of the glass tube and the glass tube connected by a rubber tube, from the glass tube <br/> placed in a horizontal glass tube, which stands upright in the height of 1m The length of water penetration into the water-blocking material in the glass tube placed horizontally after 24 hours is measured. Those having a short water running length have good water running preventing properties. 3) Water impermeable tape for slot A 1.6 mm wide, 1.2 mm deep groove (slot) is formed along a length direction on a polyethylene cylindrical rod having a diameter of 1.5 cm.
Carved Ru. First, an optical fiber core tape having a thickness of 400 μm and a width of 1.4 mm is put into the groove of the slot bar, and then a water impermeable tape for a slot is put thereon, and then an optical fiber core tape is put thereon. The whole of the above (2)
In the water running prevention test according to 2) , cover the surface with a tape with a running water length of 50 cm or less, cover it with vinyl tape, place both ends open horizontally, and stand upright at the end with a 10 mm inner diameter glass. The tube was connected with a rubber tube, and a vertical glass tube was placed 1 m from the horizontal bar.
Filled with water up to the height, the horizontal after 24 hours
Measure the length of water infiltrated by the placed rod into the water barrier material.

Those having a short water running length have good water running preventing properties. Example 1 Alternating copolymer of isobutylene and maleic anhydride (intrinsic viscosity 1.0 , 30 ° C. , dimethylformaldehyde solution ,
100 parts by weight of Kuraray Co. , Ltd. , Isovan-10), 27 parts by weight of sodium hydroxide and 373 parts by weight of water were mixed and dissolved by heating, and the sodium salt of the copolymer (degree of neutralization: 0.
An aqueous solution of 52) was obtained.

Next, 0.5 parts by weight of polyethyleneimine having an average degree of polymerization of 1000 was added as a cross-linking agent to 500 parts by weight of the aqueous solution, followed by sufficient mixing. When a water-absorbent resin was prepared from this mixture solution, the resulting resin
The water absorption capacity was 220 times with distilled water and 27 times with artificial seawater.

30 parts by weight of glycerin was mixed with 500 parts by weight of the above mixture aqueous solution diluted to a solid content of 15% by weight, and this was added to a spun-like processed yarn LLW (trade name , manufactured by Kuraray Co. , Ltd.). Was applied so that the amount of adhering was 50% by weight / processed yarn, followed by heat treatment at 120 ° C. for 2 hours after air-drying to obtain a water-blocking yarn.

The water-imperviousness of the thus obtained water-impervious yarns
Examination by the method (1) of the above (2) showed that the running length of the artificial seawater was 25 cm, which was a good result. This water-impervious yarn was flexible, had good workability during cable production and cable connection work, did not fall off the coating layer due to bending or impact, and had excellent cushioning properties for optical fibers. Comparative Example 1 A water-impervious thread was produced in the same manner as in Example 1 except that glycerin as a plasticizer was not used in Example 1, and the water running length was measured. Was also large. In addition, the obtained impervious yarn is hard and lacks flexibility, so the workability during cable manufacturing and cable connection work is poor, the coating layer falls off due to bending and impact, and the cushioning property against optical fibers is poor. there were. Example 2 Polyester nonwoven 70500 / WSO (Unitika Ltd., basis weight 50 g / m ²⁾ sodium salt solution of a copolymer of isobutylene and maleic anhydride used in Example 1, a polyethylene imine, a mixed solution of glycerol (Solid content: 15% by weight) in terms of an attached amount (solid content conversion) of 70 g / m
² and then air-dried.
Heat treatment was performed for a time to obtain a water-absorbent sheet. The obtained sheet was slit into a width of 2.5 cm in the longitudinal direction to prepare a press- winding tape for water shielding.

The running length of the water-repellent holding tape is set to the front.
According to the method described in (2) 2) above, 26
cm and good results were obtained. Further, the holding tape has good workability flexible during cable manufacturing and during cabling work, no falling of the coating layer due to bending and impact, and was excellent in cushioning properties for fiber optic cables. Comparative Example 2 In Example 2, except that glycerin as a plasticizer was not used, a water-repellent holding tape was produced in the same manner as in Example 2 and the water running prevention property was examined. The water running length was found to be artificial seawater. Was 42 cm, which was larger than that of Example 2.

Further, the obtained press-wrap tape is hard and lacks flexibility, so that the workability during cable manufacturing and cable connection work is poor, and the coating layer falls off due to bending or impact, and cushioning property for optical fibers is observed. Was inferior. Aqueous solution of the sodium salt of a copolymer of isobutylene and maleic anhydride used in Example 3 Example 1, polyethylene imine, a mixture of glycerol solution (solid content 15 wt%), thickness 40μ
5 m polyester film with a coating thickness of 5 on one side
Coating was performed to a thickness of 0 μm, followed by air drying and heat treatment at 120 ° C. for 2 hours.

The double-coated film thus obtained was slit to a width of 1.3 mm to obtain a water-blocking tape for slots.

The water running-preventing property of the water-blocking tape for slots was evaluated by using the water-repelling press-wrap tape prepared in Example 2.
The water running length was as good as 26 cm with artificial seawater when examined by the method of 3) of the above (2) . Further, the water-blocking tape for a slot was flexible, had good workability in cable production and cable connection work, did not fall off the coating layer due to bending or impact, and was excellent in cushioning properties for optical fibers. Example 4 500% 20% aqueous solution of sodium polyacrylate (manufactured by Wako Pure Chemical Industries, Ltd., degree of neutralization 1, degree of polymerization 2700-7500)
0.8 parts by weight of glycerin diglycidyl ether was added to parts by weight and mixed well. When a water-absorbing resin was prepared from this mixture solution, the water absorption of the obtained resin was 78 times with distilled water and 14 times with artificial seawater. A mixture obtained by adding and mixing 40 parts by weight of propylene glycol with respect to 500 parts by weight of the above mixed solution was applied to the same polyester nonwoven fabric as used in Example 2 so that the adhered amount was 100 in terms of solid content.
g / m ^2, and then air-dried.
For 1 hour to obtain a water-absorbent sheet. The resulting slit into 2.5cm wide sheet in the longitudinal direction, push for impermeable
A winding tape was produced.

[0042] before the water ran the length of the shielding water for holding tape
When measured by the method described in 2) of (2) above,
A good result of 0 cm was obtained. Further, the holding tape was flexible, had good workability during cable manufacturing and cable connection work, had little falling off of the coating layer due to bending and impact, and had excellent cushioning properties for optical fiber cables.

[0043]

According to the present invention, there is provided one or more compounds selected from the group consisting of a neutralized product (A) obtained by reacting a carboxyl group-containing polymer with a basic substance, a polyepoxy compound and a polyamine compound. Provided is a water-shielding material obtained by applying a mixture of two or more kinds of a crosslinking agent (B) and a polyhydric alcohol (C) to a support and performing a crosslinking treatment. This water-blocking material uses the above-mentioned neutralized product (A) and cross-linking agent (B) by using a polyhydric alcohol which is hydrophilic and has good compatibility with other components as a plasticizer.
It improves the hardness of the water-absorbing coat layer consisting of and is flexible without sacrificing the water-blocking performance, has good workability during cable manufacturing and cable connection work, and does not fall off the coating layer due to bending or impact. It also has excellent cushioning properties for optical fibers.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view of a slot type optical fiber cable using a water-blocking material of the present invention.

FIG. 2 is an enlarged cross-sectional view of a conventional water running prevention type optical fiber cable.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Optical fiber core tape 2 Optical fiber 3 Spacer 4 Jacket layer 5 Aluminum tape 6 Press- winding waterproofing tape 7 Slotting waterproofing tape 8 Tension member 9 Jelly 10 Waterproof thread

Claims (1)

(57) [Claims] Claims: 1. An α-olefin or vinyl compound and
Copolymers and polymers with maleic acid or its derivatives
From polymers containing lylic acid or methacrylic acid as the main monomer
One or more addition polymer systems selected from the group consisting of
One or more crosslinks selected from the group consisting of a neutralized product (A) obtained by reacting a basic substance with a carboxyl group-containing polymer as a polymer, a polyvalent epoxy compound and a polyvalent amine compound A water-blocking material obtained by applying a mixture of the agent (B) and the polyhydric alcohol (C) to a support and performing a crosslinking treatment.