JP3312397B2 - Waterproof tape for optical cable and method of manufacturing the same - 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-stop tape for an optical cable, which prevents water from running in the longitudinal or inward direction of the cable when water enters the cable.

[0002]

2. Description of the Related Art An optical cable as a communication cable is installed underground or on the seabed, and is always surrounded by water, and it is extremely important to improve waterproofness.

[0003] If a coating material such as an optical cable sheath installed underground or on the sea floor is broken due to cracks or pinholes, water penetrates and acts on the optical fiber to cause communication failure.

[0004] For this reason, a contrivance has been made to accommodate a waterproof material in an optical cable to impart water-blocking properties. More recently, a method has been proposed in which a water-absorbing tape coated with a high-molecular-weight water-absorbing resin is wound around the optical cable in order to prevent water that has entered the optical cable from running. In this method, the polymer water-absorbing resin absorbs water that has penetrated and swells or falls off, thereby filling the groove accommodating the optical fiber and preventing water running in the longitudinal direction and inward of the cable, An attempt is made to minimize a damaged portion in an optical cable.

[0005]

However, these water-absorbing tapes have the following problems.

(1) Powder or particles of a polymer water-absorbing resin is mixed with a binder resin solution in a thin nonwoven fabric or the like to form a coating liquid, and the coating liquid is applied and fixed. Excellent in the adhesiveness of the water-soluble resin, although the resin is hard to fall off, because the binder resin component is interposed on the surface of the polymer water-absorbing resin, when water invades,
Since it takes time for water to be absorbed by the polymer water-absorbing resin, there is a disadvantage that the distance until water is stopped is increased.

(2) The water-stop tape for an optical cable in which the polymer water-absorbent resin powder is sandwiched by a tape base material such as a thin nonwoven fabric, because the polymer water-absorbent resin powder is not exposed on the surface, Even if the tape absorbs moisture, it is easy to handle without stickiness, but because the polymer water-absorbent resin powder is sandwiched in the nonwoven fabric, it takes time to absorb water, and the distance to stop water is longer. become longer. Furthermore, since the polymer water-absorbent resin is not fixed to the nonwoven fabric, the polymer water-absorbent resin falls off when slitting from a wide sheet to a practical tape width or during work such as taping.
Further, since the so-called three-layer structure in which the powder of the polymer water-absorbing resin is sandwiched by a tape base material such as a thin nonwoven fabric, there is a problem that the thickness of the water-stopping tape is increased.

An object of the present invention is to solve the above problems and to provide a waterproof tape for optical cables which satisfies both the cable moldability and the waterproof property.

[0009]

The present invention employs the following configuration to achieve the above object. That is, the optical cable for waterproofing tape of the present invention, a resin having a self-weight of 60 times or more the absorption capacity (A) is, although absorption capacity is low, is coated with a water absorption rate of the large resin (B), and It is characterized in that such a coated structure is bonded to a fabric substrate with a binder resin (C).

[0010]

[0011]

[0012] Also, the manufacturing method of the optical cable for waterproofing tape of the present invention is low water absorption capacity, the absorption rate greater resin
(B) is dissolved in a solvent in which the resin (B) dissolves but the resin (A) described below does not dissolve, and then the resin (A) granules having a water absorption capacity of 60 times or more of its own weight are mixed. The mixture is mixed with a binder resin (C) to form a water-absorbent resin composition, and the composition is applied to at least one surface of a fabric substrate.

[0013]

The present invention focuses on maximizing the use of a resin (A) having excellent water absorption capacity, and has conducted intensive studies.
(A) and resin with low water absorption but high water absorption
It has been determined that three types of resin compositions containing (B) and further a binder resin (C) as essential components maximize the performance of the resin (A). That is, by enclosing the resin (A) with a specific resin (B) having a low water absorption capacity but a high water absorption rate, the stability of the resin (A) is improved, and at the same time, the tape made of the binder resin (C) is used. This has led to improvements in the adhesion to a substrate.

That is, in the present invention, the resin (A) is replaced with the resin (B)
The particles coated with the resin are fixed to the base material with the binder resin (C). By adopting such a structure, the properties of the resin (A) can be utilized 100% without lowering the water absorption capacity. Further, the present invention has succeeded in providing a water-stopping tape which can improve the adhesion to a base material, and exhibit a water-stopping function in a very short time.

The fabric substrate used in the present invention includes a woven fabric,
A nonwoven fabric is preferably used, but a long-fiber nonwoven fabric formed by a spunbond method is particularly preferable in terms of price, strength, and productivity. As a material constituting such a base material, for example, synthetic fibers such as polyester, polypropylene, and nylon can be used.
From the viewpoint of strength and rigidity during taping, a long-fiber nonwoven fabric made of polyester fiber is preferably used.

The resin (A) having excellent water absorption capacity used in the present invention
Is a resin having a water absorption capacity of 60 times or more of its own weight, in other words, at least 50 ml / g, preferably 100 to 100 ml / g.
A resin having a water absorption capacity of 1000 ml / g, especially a synthetic resin, which is not corroded or decomposed by microorganisms.

The above-mentioned water absorption ratio is determined by filling a tea pack with a certain amount of resin (average particle diameter: 60 μm), immersing the bag in artificial seawater (Aquamarine; manufactured by Yasu Yakuhin Co., Ltd.) for 5 minutes, The rate of weight increase when draining for 5 minutes.

Examples of the resin having such a water absorbing ability include, for example, a starch or cellulose, a water-soluble monomer containing a carboxylic acid group or a sulfonic acid group and / or a monomer which becomes water-soluble by hydrolysis. A copolymer containing an agent as an essential component, an acrylate-based crosslinked product, an acrylate / acrylamide copolymer, an isobutylene / maleic acid copolymer, or the like can be used.

These copolymers include, for example, a hydrolyzate of a starch-acrylonitrile graft copolymer and a hydrolyzate of a cellulose-acrylonitrile graft copolymer, for example, a cross-linked starch or cellulose such as a cross-linked carboxymethyl cellulose. , Cross-linked acrylic acid-acrylamide copolymer, cross-linked sulfonated polystyrene, saponified vinyl ester-unsaturated carboxylic acid copolymer, cross-linked polyacrylate, cross-linked acrylic acid-acrylate copolymer, cross-linked isobutylene-maleic anhydride An acid copolymer, a cross-linked carboxylic acid-modified polyvinyl alcohol, a self-cross-linked polyacrylate, or the like can be used.

Among these copolymers, partially hydrolyzed cross-linked polyacrylamide, cross-linked acrylic acid-acrylamide copolymer, cross-linked polyacrylate, cross-linked acrylic acid-acrylate copolymer, cross-linked isobutylene-anhydride The maleic acid copolymer and the crosslinked carboxylic acid-modified polyvinyl alcohol may have excellent water absorption capacity.

Such a copolymer is used in the resin composition of the present invention as a granular material. In this case, the average particle size is about 100 μm or less, preferably 20 to 80 μm, particularly preferably 40 to 75 μm, from the viewpoint of the water absorption ratio, coating properties and film properties.

The resin (B) having a low water absorption capacity but a high water absorption rate used in the present invention includes, for example, a block copolymer or a copolymer having a hydrophilic group and a hydrophobic polymer chain or a copolymer chain. Graft copolymers can be used. As such a copolymer,
Specifically, for example, a (polystyrene)-(polybutadiene)-(polystyrene) block copolymer is dissolved in a solvent such as an organic solvent, and acrylic acid, methacrylic acid, or the like is added to the double bond or addition polymerization (grafting is performed). And then neutralized with an alkali. Such copolymers are not limited to those dissolved in a solvent, but include those of a dispersion system such as fine dispersion.

The above resin (B) is dissolved, but the later resin
As the solvent in which (A) does not dissolve, for example, acetone,
Ordinary organic solvents such as methyl ethyl ketone, methyl isobutyl ketone, and isopropyl alcohol,
Furthermore, cycloparaffinic compounds such as cyclohexane and methylcyclopentane, and thinners, toluene, and petroleum aromatic compounds such as xylene can be used, and preferably at least one selected from toluene, dimethylformamide, xylene, and isopropyl alcohol. One type can be used according to the solubility (difference in solubility) between the resin (A) and the resin (B). The above resin (B) of the present invention
The resin solution of (1) requires at least 5% by weight as a solid content from the viewpoint of protection of the resin (A),
It is adjusted within the range of 50% by weight according to the viscosity of the final resin composition. The viscosity of the resin composition is preferably at least 1000 cps, and more preferably in the range of 2000 to 5000 cps, from the viewpoint of coating properties and properties of the coating film.

The present invention is characterized in that the resin (A) is present in the resin composition as a granular material. By keeping such a shape, the resin (A)
The water absorption capacity function was exhibited 100%.
For this purpose, the resin (A) is protected by covering it with a resin (B) having a low water absorption capacity but a high water absorption rate. That is, it is important in the present invention to protect the resin (A) with the resin (B) so that the resin (A) is not contaminated with the binder resin (C). Due to the presence of the resin (B), the water absorption capacity function of the resin (A) is stably maintained, and the resin (A) is surely and firmly reinforced by the binder resin (C) via the resin (B). To
It was able to adhere to the fabric substrate.

In order to exhibit such protective properties, a resin
(A) and the resin (B) in the combined resin solid content, the resin (B)
Is preferably at least 15% by weight, more preferably 20 to 60% by weight, particularly preferably 30 to 40% by weight.
It is blended in the range.

If the water absorption rate of the resin (B) of the present invention is increased, the water stoppage can be improved. In order to improve the water absorption rate, it is preferable to add a surfactant to the resin (B). The compounding amount is at least 1% by weight, preferably 3 to 10% by weight.

As such a surfactant, any surfactant can be used as long as it lowers the interfacial tension of artificial seawater (aquamarine), and any of nonionic, anionic, cationic and amphoteric surfactants can be used. However, among them, it is preferable to use a nonionic surfactant, particularly a nonionic surfactant such as a polyoxyalkylene, an ester, or an alkylolamide. Among these nonionic surfactants, polyoxyalkylene-based surfactants are particularly preferable, and further, an oxyethylene chain, an oxypropylene chain,
Those having an oxybutylene chain or an oxystyrene chain are preferred. Such a surfactant is preferably added in an amount of 3% by weight or more, particularly preferably in the range of 5 to 8% by weight.

The binder resin (C) used in the present invention may be any resin that dissolves in the above-mentioned solvent that dissolves (B), such as an acrylic resin, a polyurethane resin,
Although there are unsaturated polyester resins, rubber resins such as isobutylene rubber, etc., 100% synthetic products having no biodegradability are preferably used.

The amount of the binder resin in the resin composition is preferably 5 to 25% by weight, more preferably 7 to 25% by weight.
The range of 20% by weight is good from the viewpoint of sticking property, water absorption rate and water stoppage. If the amount of the binder resin is too large, the water stopping property and the water absorption rate tend to decrease.

As described above, the water-blocking tape for an optical cable according to the present invention can be produced. The resin (B) having a low water absorption ratio but a high water absorption rate dissolves (B), but
After dissolving in a specific solvent in which (A) described below does not dissolve, a surfactant is added if necessary, and the above resin (A) granular material is mixed with such a resin solution. Binder resin (C) is blended with this mixture to form a water-absorbing resin composition,
This composition is to be applied to at least one surface of a fabric substrate.

The coating method may be any method.
Preferably, a knife coating method in which the thickness of the coating film can be accurately determined is preferable.

The water-stop tape of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of a water-stopping tape 1 of the present invention, and shows an example of a structure in which a water-absorbing resin composition is applied to a fabric substrate 3.

FIG. 2 is a schematic sectional view when the water-stop tape 1 of FIG. 1 is used for an optical fiber cable. The optical fiber cable has a structure in which an optical fiber tape 5 is accommodated in a concave portion provided in a slot rod 6, covered with a waterproof tape 1, and further covered with a sheath 4. 7 is a tension member.
When the sheath 4 is damaged and water enters, the water-absorbent resin composition of the water-stop tape 1 absorbs water and expands, thereby exhibiting an action of stopping the entry of water.

[0034]

The present invention will be further described with reference to examples.

Examples 1 to 5 and Comparative Examples 1 and 2 The following compositions were prepared to obtain a water-absorbent resin composition having a viscosity of 2000 to 2500 cps. (Resin composition) Resin (A): Crosslinked acrylate polymer (average particle size 60
μ) Resin (B): Alkaline neutralized product of acrylic acid graft copolymer of styrene butadiene block copolymer (60% by weight)
(Toluene solution) Binder resin (C): polyurethane resin (9% by weight toluene solution) Surfactant (D): polyoxyalkylene adduct of phenylnonyl alcohol The compounding ratio of the above composition is shown in Table 1. The compounding method is as follows.

That is, the resin (B) was added to the toluene solution of the resin (B).
(A) is mixed and mixed, and a binder resin (C) is added to the mixed solution.
Was mixed and prepared. When mixing the surfactant (D), mix the surfactant (D) with the resin (B) beforehand,
(A) was mixed.

The water-absorbent resin dispersion thus obtained was applied to a polyester long-fiber nonwoven fabric (single fiber fineness: 2 d, basis weight: 70 g / m ² , thickness: 0.2 mm) by a knife coating method at a coating amount of 100 g / m 2. After applying on one side with ² ,
After drying, a substrate for a waterproof tape was obtained.

Table 1 shows the results of evaluation of the performance of the base material for water-stopping tape in terms of sticking property, water absorption rate, water absorption ratio, and water-stopping property. (Evaluation method) Sticking property: Evaluated by the state of the coating film when a cellophane tape was stuck to the coating film surface and peeled in the vertical direction. ：: No change was observed in the coating film even after peeling. ：: Part of the coating film was peeled off by sticking to the tape. X: All of the coating film was peeled off by sticking to the tape. Water absorption rate: artificial seawater (Aquamarine) Swelling and gelling time when 0.5 ml was dropped.

Water absorption ratio: A sample of 5 cm square was immersed in 100 ml of artificial seawater (aquamarine) for 10 minutes, then drained with a 300 mesh sieve for 5 minutes, weighed, and the ratio to the initial weight was calculated by the following formula. Determined by

Water absorption ratio (%) = (weight after draining / initial weight) × 10
0 Water-stopping property: A water-stopping tape sample was stuck on a 1.5 mm × 2.0 mm × 8 m hollow groove with the resin coating surface facing down, and one end of the water groove and 1 m 2 of water column When the artificial seawater was supplied at the height, dropped, and supplied to the groove, the distance until the running water stopped was evaluated.

[0041]

[Table 1] As is clear from Table 1, Examples 1 to 5 are Comparative Examples 1 to 5.
It can be seen that the required function as a waterproof tape for optical cables is superior to that of No. 2. That is, in Comparative Example 1, since the binder resin covers the surface of the resin (A), there is no problem in the adhesion to the nonwoven fabric, but the water absorption capacity, the water absorption speed and the water stopping property are inferior. In Comparative Example 2, the resin (A) and the resin
In the system of only (B), there is no problem in water absorption rate, water absorption capacity, and water stoppage, but it is not practical because it has no sticking property to the nonwoven fabric.

Example 1 is slightly inferior to the other examples 2 to 5 in water-stopping property, but it is not practically impossible. From the viewpoint of practicality, those of Examples 2 to 5, particularly those of Example 2, are excellent.

[0043]

The water-sealing tape for optical cables of the present invention has excellent performances of sticking property of ○, water absorption speed of 50 seconds or less, water absorption ratio of 600% or more, and water-stopping of 7 m or less. In addition to having the ability to immediately stop water when water enters the cable, the resin coating does not fall off during work such as taping to the cable, and has the effect of being excellent in workability.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a water-stopping tape of the present invention.

FIG. 2 is a schematic sectional view showing an example of an optical fiber cable using the water-stopping tape of the present invention.

[Explanation of symbols]

 1: Water-blocking tape 2: Water-absorbing resin composition 3: Fabric base material 4: Sheath 5: Optical fiber tape 6: Slot rod 7: Tension member

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C09K 3/00 G02B 6/44 H01B ⁷ /18-7/282

Claims (8)

(57) [Claims] 1. A resin (A) having a water absorption capacity of at least 60 times its own weight, a resin having a low water absorption capacity but a high water absorption rate
A water-stop tape for an optical cable, wherein the tape is coated with (B), and the coated structure is bonded to a fabric substrate with a binder resin (C). 2. The resin (A) is a crosslinked polyacrylamide.
Partial hydrolyzate, cross-linked acrylic acid-acrylamide
Polymer, cross-linked polyacrylate, cross-linked acrylic acid
Lylic acid ester copolymer, cross-linked isobutylene-anhydromale
Inic acid copolymer and cross-linked carboxylic acid-modified polyvinyl alcohol
At least one type of granular material selected from
The waterproof tape for optical cables according to claim 1. 3. The polymer according to claim 1, wherein said resin (B) has a hydrophilic group.
Or copolymers and hydrophobic polymer chains or copolymer chains
Block copolymer or graft copolymer consisting of
The waterproof tape for optical cables according to claim 1. 4. The resin (B) is a combination of the resin (A) and the resin (B) .
At least 15 % by weight in the resin solids
Optical cable according to any one of claims 1 to 3 is intended
For waterproof tape. 5. The water-stop tape for an optical cable according to claim 1, wherein the resin (A) has a particle size of 100 μm or less. 6. The waterproof tape for optical cables according to claim 1, wherein said fabric substrate is a polyester long-fiber non-woven fabric. 7. A resin (B) having a low water absorption capacity but a high water absorption rate is dissolved in a solvent in which the resin (B) dissolves but the resin (A) described below does not dissolve. A granular material of the resin (A) having the above-mentioned water absorption capacity is mixed, a binder resin (C) is mixed with the mixed solution to form a water-absorbing resin composition, and the composition is coated on at least one surface of the fabric substrate. A method for producing a waterproof tape for optical cables, characterized by being applied. 8. The waterproof tape for optical cables according to claim 7, wherein the solvent is at least one selected from toluene, dimethylformamide, xylene, and isopropyl alcohol.