JP3389048B2 - Waterproof tape - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof tape used for waterproofing optical fiber cables.

[0002]

2. Description of the Related Art Conventionally, when an outer cover member of an optical fiber cable is damaged and water intrudes from the outer cover member, the movement of the water is suppressed by absorbing the water that is trying to move in the longitudinal direction of the cable. There is known a water-stopping tape (for example, see JP-A-3-200206 and JP-B-7-119335).

FIG. 1 is an explanatory view showing a cross-sectional structure of an optical fiber cable on which a water blocking tape is mounted. In the optical fiber cable shown in the figure, a rod 13 having a groove 12 extending in the longitudinal direction (depth direction of the paper) is provided on the circumferential surface of a tensile body 11, and a water blocking tape 14 is provided on the circumferential surface of the rod 13. Is wound around, and the outer skin member 15 is formed on the peripheral surface of the water blocking tape 14.
An optical fiber core wire 16 is accommodated therein.

FIG. 2 is an explanatory view showing an example of a cross-sectional structure of the water blocking tape 14 mounted on the optical fiber cable shown in FIG. The water blocking tape 14 is composed of a support 17 made of a woven or non-woven fabric, a water absorbing layer 18 formed on the surface of the support 17, and a cover cloth 19 provided on the surface of the water absorbing layer 18. There is.

Water absorbing layer 18 formed on the surface of support 17
Is composed of water-absorbent resin particles dispersed in an organic polymer binder. The water-absorbent resin particles dispersed in the water-absorbent layer 18 absorb water to become swollen particles, and some of the water-absorbent resin particles are separated from the water-absorbent layer 18, permeate through the cover cloth 19 and move to the outside, and the gap in the cable It is filled with water and exerts a water blocking effect. The water absorbing layer 18 is formed by applying a composition containing water absorbing resin particles, a binder, and an organic solvent to the surface of the support 17 and drying the coating film to remove the organic solvent.

The cover cloth 1 on the surface of the water absorbing layer 18
9 is provided for preventing stickiness of the tape surface, blocking of the tape, and the like. The cover cloth 19 is made of coarse mesh fabric so as not to impede migration of water-absorbent resin particles (swelling particles). There is.

The waterproof tape 14 having the sectional structure as shown in FIG. 2 is mounted by being wound around the rod (13) with the cover cloth 19 inside (on the groove 12 side).

In the optical fiber cable having the structure shown in FIG. 1, when the outer cover member 15 is damaged and water enters into the cable from there, the water absorbing layer of the water blocking tape 14 wound around the position corresponding to the damaged portion ( 18) absorbs the invading water and swells, sealing the gap in the groove 12. At the same time, some of the water-absorbent resin particles (swelling particles) overcome the fixing force of the binder and move from the water-absorbing layer (18) into the groove 12 to seal the minute gap in the groove 12.

[0009]

However, from the viewpoint of exerting an excellent water blocking effect on the water blocking tape, it is desirable that the amount of the water absorbing resin particles contained in the water absorbing layer is as large as possible. It is desirable that the amount of the binder that inhibits the swelling of B is as small as possible.

However, when the proportion of the binder in the water-absorbent layer is low, for example, 10 parts by weight or less per 100 parts by weight of the water-absorbent resin particles, the water-blocking tape provided with such a water-absorbent layer is as follows. Causes problems such as.

(1) The water-absorbent resin particles cannot be fixedly held in the water-absorbent layer, and the water-absorbent resin particles fall off from the water-absorbent layer during cutting and construction of the water-stop tape (when wound around a rod). This leads to reduced workability and environmental pollution.

(2) Good adhesion may not be exhibited between the support and the water-absorbing layer, and the water-absorbing layer may peel off from the surface of the support during the production and construction of the waterproof tape. .

(3) When a cover cloth is provided on the surface of the water-absorbing layer, good adhesiveness is not exhibited between the water-absorbing layer and the cover cloth, and the surface of the water-absorbing layer is covered with the cover when the waterproof tape is applied. The cloth may peel off.

(4) In order to form a water-absorbing layer having a low binder content, a composition having a low binder content (high water-absorbent resin particle content) is applied to the surface of a support as a forming composition. There is a need to. However, a composition having a high proportion of water-absorbent resin particles has extremely low coating properties, and a coating film formed from such a composition has unevenness due to streak-like coating marks by a coater, leveling failure, etc. As a result, it is not possible to form a water absorbing layer that is homogeneous and has excellent surface smoothness.

(5) In the step of forming the water absorbing layer, in order to improve the coating properties of the forming composition, it is necessary to use a large amount of an organic solvent to make the viscosity of the composition as low as possible. However, when such a composition having a low viscosity is applied to the surface of a support made of a woven fabric or a nonwoven fabric, the organic solvent in the composition and the binder component dissolved in the composition permeate the support and leak out. And
As a result, it is impossible to form a water absorbing layer (manufacture of a water blocking tape), or the resulting water blocking tape is prone to the problems (1) to (3).

The present invention has been made based on the above circumstances. A first object of the present invention is to provide a water blocking tape that is more excellent in water blocking performance than conventional ones. A second object of the present invention is to provide a water-stop tape in which water-absorbent resin particles are securely fixed and held and do not fall off during cutting and construction. A third object of the present invention is to provide a water blocking tape comprising a water absorbing layer having good adhesiveness to a support and a cover cloth. A fourth object of the present invention is to provide a water blocking tape having a water absorbing layer that is homogeneous and has excellent surface smoothness. The fifth object of the present invention is
An object of the present invention is to provide a water blocking tape in which the binder component does not leak from the support.

[0017]

The water-blocking tape of the present invention comprises:
A support (1) made of a woven or non-woven fabric, a sealing layer (2) formed on the surface of the support (1), and a water absorbing layer (3) formed on the surface of the sealing layer (2). The waterproofing tape (2), wherein the sealing layer (2) comprises 100 parts by weight of a rubber-based binder and 50 to 400 parts by weight of a non-organic filler having a particle diameter of 1 to 10 μm. The water-absorbent layer (3) contains 100 parts by weight of water-absorbent resin particles, 2 to 10 parts by weight of a rubber-based binder, and 0.
It is characterized by containing 5 to 20 parts by weight.

The waterproof tape of the present invention comprises 100 parts by weight of a rubber binder and 50 to 400 parts by weight of an inorganic filler having a particle size of 1 to 10 μm on the surface of a support (1) made of a woven or non-woven fabric. And a composition containing an organic solvent (hereinafter, also referred to as "composition for forming a sealing layer"). ] And the coating film is dried to form a sealing layer (2),
The surface of the sealing layer (2) contains 100 parts by weight of water-absorbent resin particles, 2 to 10 parts by weight of a rubber-based binder, 0.5 to 20 parts by weight of an isocyanate compound, and an organic solvent.
A composition having a viscosity of 20 poise or less at 5 ° C. [hereinafter,
It is also referred to as a "water absorbing layer forming composition". ] And the coating film is dried to form a water absorbing layer (3).

In the waterproof tape of the present invention, it is preferable that a cover cloth (4) is provided on the surface of the water absorbing layer (3).

[0020]

[Action]

[1] Since the proportion of the water-absorbent resin particles contained in the water-absorbent layer is extremely high and the proportion of the binder that inhibits the swelling of the water-absorbent resin particles is extremely low, as is clear from the results of Examples described later, It is possible to obtain a water blocking effect superior to that of the conventional tape.

[2] Even if the proportion of the binder contained in the water absorbing layer is extremely low, the water absorbing resin particles are surely contained in the water absorbing layer because the isocyanate compound is contained in the water absorbing layer. The water-absorbing layer has good adhesiveness to the support (sealing layer) and the cover cloth, while being firmly fixed and held on.

[3] By setting the viscosity of the water absorbing layer forming composition to 20 poise (25 ° C.) or less, the formed water absorbing layer becomes homogeneous and has excellent surface smoothness.

[4] Since the sealing layer is formed on the surface of the support, the binder component in the composition permeates the support even when a water absorbing layer forming composition having a low viscosity is applied in the production stage. It will not leak out.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION The water blocking tape of the present invention will be described in detail below. FIG. 3 is an explanatory view showing an example of the cross-sectional structure of the water blocking tape of the present invention. The waterproof tape shown in FIG. 1 includes a support 1 made of a woven fabric or a non-woven fabric, a sealing layer 2 formed on the surface of the support 1, and a water absorbing layer 3 formed on the surface of the sealing layer 2. , And a cover cloth 4 provided on the surface of the water absorbing layer 3.

[Support] As the support (1) constituting the waterproof tape of the present invention, synthetic fibers such as polyester, nylon, which are not broken by the tension when wound around the rod and are not decomposed by microorganisms, Woven and non-woven fabrics made of polypropylene, rayon, vinylon; composite materials such as polyester / polyethylene composites, polyester / aramid composites and the like can be preferably used.

[Sealing Layer] The sealing layer (2) constituting the waterproof tape of the present invention contains a rubber binder and an inorganic filler. In addition, a surfactant,
Antiaging agents, synthetic resins and the like may be contained.

Examples of the rubber-based binder constituting the sealing layer include styrene-butadiene rubber, butadiene rubber,
Isoprene rubber, chloroprene rubber, isobutylene rubber, butyl rubber, ethylene propylene rubber, chlorosulfonated polyethylene rubber, silicone rubber, trifluorochloroethylene rubber, vinylidene fluoride rubber, dihydroperfluoroalkyl acrylate rubber, polyurethane rubber, vinyl rubber, nitrile Examples thereof include rubber and acrylic rubber, and these can be used alone or in combination of two or more kinds.

Examples of the inorganic filler constituting the sealing layer include calcium carbonate, hydrous calcium silicate, aluminum oxide, aluminum hydroxide, hydrous aluminum silicate, magnesium oxide, magnesium hydroxide, magnesium carbonate, magnesium silicate, Powders of titanium oxide, zinc oxide, silica, bentonite, kaolinite, carbon black, zeolite, activated clay, clay, talc and the like can be mentioned, and these can be used alone or in combination of two or more kinds. .

The particle size of the inorganic filler is from 1 to 1 from the viewpoint of dispersibility in a rubber binder and a sufficient sealing effect.
It is set to 0 μm .

The content of the inorganic filler in the sealing layer is usually 50 to 400 parts by weight, preferably 100 to 300 parts by weight, based on 100 parts by weight of the rubber binder.
It is considered to be part by weight. When this proportion is less than 50 parts by weight, a sufficient sealing effect cannot be achieved, and when this proportion exceeds 400 parts by weight, the adhesiveness of the sealing layer to the support and the water absorbing layer is impaired. .

When a water-absorptive composition having a low viscosity is applied in the step of producing a water-stop tape (application step of a water-absorptive layer-forming composition) because a sealing layer is formed on the surface of the support. Even in this case, it is possible to reliably prevent the binder component in the composition from leaking through the support.

[Water Absorbing Layer] The water absorbing layer (3) constituting the water blocking tape of the present invention contains water absorbing resin particles, a rubber binder, and an isocyanate compound.

The water-absorbent resin particles constituting the water-absorbing layer include
There is no particular limitation as long as it is made of a synthetic resin that satisfies the conditions that it is insoluble in water, absorbs about 30 to 1000 times its own weight of water, swells, and is not decomposed by microorganisms. Any of the conventionally known waterproof tapes can be used. Specific examples of such water-absorbent resin particles include acrylic acid-based crosslinked products, saponified products of vinyl acetate-acrylic acid ester copolymers, reaction products of polyvinyl alcohol and maleic anhydride, polyvinyl alcohol-maleic acid copolymers. Examples include cross-linked products of polymers, acrylate-acrylamide copolymers, modified products of polyethylene oxide, cross-linked products of isobutylene-maleic anhydride copolymers, cross-linked products of sulfoalkyl acrylate-acrylic acid copolymers, and the like. These can be used alone or in combination of two or more.

The rubber binder constituting the water absorbing layer is selected from rubber materials having no reactivity with isocyanate compounds. Specific examples thereof include those exemplified as the binder constituting the sealing layer. Of these, synthetic rubbers containing no halogen atom are preferable, and butyl rubber, ethylene propylene rubber and butyl rubber / ethylene propylene are particularly preferable. It is a blended rubber.

The content of the rubber binder in the water absorbing layer is usually 2 to 10 parts by weight, preferably 5 to 10 parts by weight, based on 100 parts by weight of the water absorbing resin particles. When the content ratio of the rubber-based binder is less than 2 parts by weight, in a water-stop tape having such a water-absorbing layer, water-absorbing resin particles fall off, the water-absorbing layer peels off from the surface of the support, This may cause peeling of the cover cloth from the surface. On the other hand, when the content ratio of the rubber-based binder is more than 10 parts by weight, the water blocking tape having such a water absorbing layer cannot exhibit a water blocking effect superior to that of the conventional water blocking tape.

As the isocyanate compound constituting the water absorbing layer, one or more isocyanate groups (NCO) are used.
Can be selected from compounds having: and derivatives thereof. Specific examples of the isocyanate compound include monoisocyanate compounds such as ethyl isocyanate and phenyl isocyanate; diphenylmethane diisocyanate, methylene diisocyanate, ethylene diisocyanate, trimethylene diisocyanate, 1-methylethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate, 2- Methyl butane-1,4-diisocyanate, hexamethylene diisocyanate, heptamethylene diisocyanate, 2,2′-dimethylpentane-1,5-diisocyanate, octamethylene diisocyanate,
2,5-dimethylhexane-1,6-diisocyanate, 2,2,4-trimethylpentane-1,5-diisocyanate, nonamethylene diisocyanate, 2,
2 ', 4-trimethylhexane diisocyanate, 2,
4,4′-trimethylhexane diisocyanate, decamethylene diisocyanate, undecamethylene diisocyanate, dodecamethylene diisocyanate, tridecamethylene diisocyanate, tetradecamethylene diisocyanate, pentadecamethylene diisocyanate, hexadecamethylene diisocyanate, butene diisocyanate, 1,3-butadiene Diisocyanate compounds such as -1,4-diisocyanate and 2-butynylene-1,4-diisocyanate; 1-methylbenzol-2,
4,6-triisocyanate, 1,3,5-trimethylbenzol-2,4,6-triisocyanate, naphthalene-1,3,7-triisocyanate, biphenyl-
2,4,4'-triisocyanate, diphenylmethane-2,4,4'-triisocyanate, methyldiphenylmethane-4,6,4'-triisocyanate, triphenylmethane-4,4 ', 4'-triisocyanate,
Triisocyanate compounds such as polymeric-diphenylmethane-4,4'-diisocyanate;4,4'-
A tetraisocyanate compound such as dimethyldiphenylmethane-2,2 ′, 5,5′-tetraisocyanate can be exemplified, and a block type isocyanate compound can also be used. These isocyanate compounds can be used alone or in combination of two or more.

The content of the isocyanate compound in the water absorbing layer is usually 0.5 to 20 parts by weight, preferably 1 to 1 with respect to 100 parts by weight of the water absorbing resin particles.
It is set to 0 parts by weight. When the content ratio of the isocyanate compound is less than 0.5 parts by weight, in the water-stop tape comprising the water-absorbing layer, the water-absorbing resin particles fall off, the water-absorbing layer peels off from the surface of the support, and the surface of the water-absorbing layer. It causes the peeling of the cover cloth from the. On the other hand, when the content of the isocyanate compound exceeds 20 parts by weight, the water absorbing layer becomes brittle and the workability of the water blocking tape is significantly impaired.

The water-absorbing layer constituting the water-stop tape of the present invention may contain a surfactant, an antioxidant, a resin binder and other components. Here, as the surfactant, fatty acid soap, sodium linear alkylbenzene sulfonate, α-olefin sulfonate, alcohol sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, alkyl methyl tauride, dialkyl sulfosuccinate. Anionic surfactants such as nates; ether type, alkylphenol type, ester type,
Examples thereof include nonionic surfactants such as sorbitan ester type, sorbitan ester ether type, alkylamine type, and oxyethylene-oxypropylene block polymers. The content ratio of the surfactant is 0.1 to 5 parts by weight per 100 parts by weight of the water absorbent resin particles.

As the antiaging agent, alkylated diphenylamine, octylated diphenylamine, 4,
4 '-(α, α-dimethylbenzyl) diphenylamine, N, N'-di-2-naphthyl-P-phenylenediamine, 2,6-di-tert-butyl-4-methylphenol, 2,6-di- tert-Butyl-4-ethylphenol, mono (α-methylbenzyl) phenol, di (α-methylbenzyl) phenol, tri (α-methylbenzyl) phenol, 2,2′-methylenebis (4-
Ethyl-6-tert-butylphenol), 2,2 '
-Methylenebis (4-methyl-6-tert-butylphenol), 4,4'-butylidenebis (3-methyl-)
6-tert-butylphenol), 4,4′-thiobis (3-methyl-6-tert-butylphenol),
2,5-di-tert-butylhydroquinone, 2,5
-Di-tert-amylhydroquinone, 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, 2-mercaptomethylbenzimidazole, zinc salt of 2-mercaptomethylbenzimidazole, 1,3-bis (dimethylaminopropyl) 2-thiourea, tributylthiourea, tris (nonylphenyl) phosphite, dilauryl thiotupropionate and the like can be mentioned, and these can be used alone or in combination of two or more kinds. The content ratio of the antioxidant is 0. 0 per 100 parts by weight of the water-absorbent resin particles.
It is 2 to 2 parts by weight.

[Cover Cloth] In the water blocking tape of the present invention, it is preferable that the surface of the water absorbing layer is provided with a cover cloth (4), which prevents stickiness of the water absorbing layer in a high humidity environment. The tape blocking can be prevented. This cover cloth has a coarse mesh, for example, a low basis weight made of synthetic fibers (for example, a yarn having a diameter of 20 to 30 μm, 8 in order to prevent the water absorbent resin particles (swelling particles) from penetrating.
-15 g / m ² ) of non-woven fabric can be preferably used.

[Production method of water-stop tape] The water-stop tape of the present invention comprises a support having a sealing layer formed on the surface thereof, and a water-absorbing layer formed on the surface of the sealing layer, and if necessary, the water-absorbing layer. It can be manufactured by providing a cover cloth on the surface of the.

The sealing layer constituting the waterproof tape of the present invention is
It can be formed by applying a composition for forming a sealing layer containing a rubber binder, an inorganic filler and an organic solvent on the surface of a support, and drying the coating film to remove the organic solvent. .

The organic solvent contained in the sealing layer-forming composition is not particularly limited as long as it can dissolve the rubber-based binder contained in the composition. For example, benzene, toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, n-hexane, cyclohexane, octane, dioxane, methyl alcohol, ethyl alcohol, isopropyl alcohol, ethyl acetate, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, diethyl ether. , Ethylene dichloride, carbon tetrachloride, chloroform and the like.

The coating method of the composition for forming a sealing layer is as follows:
The coating method is not particularly limited, and a known coating method using a floating knife coater, a knife over roll coater, a reverse roll coater, or the like can be adopted. The coating amount is 10 to 30 g / m ² in terms of dry adhesion amount (adhesion amount as a sealing layer).

The water absorbing layer constituting the water blocking tape of the present invention is
It can be formed by applying a composition for forming a water-absorbing layer containing water-absorbent resin particles, a rubber-based binder, an isocyanate compound, and an organic solvent on the surface of the sealing layer and drying the coating film.

The organic solvent contained in the water absorbing layer forming composition can be selected from organic solvents capable of dissolving the rubber binder contained in the composition. Examples of the organic solvent include the organic solvents exemplified as those contained in the composition for forming a sealing layer, excluding alcohols having reactivity with an isocyanate compound.

The viscosity (25 ° C.) of the water absorbing layer forming composition is
It is usually 20 poises or less, preferably 3 to 10 poises. When the viscosity of the composition exceeds 20 poise, the coating properties of the composition are significantly deteriorated, and it is not possible to form a water absorbing layer that is homogeneous and has excellent surface smoothness. Here, the viscosity of the water absorbing layer forming composition can be easily controlled by adjusting the content ratio of the organic solvent. The method for applying the composition for forming a water absorbing layer is not particularly limited, and a known application method using a floating knife coater, a knife over roll coater, a reverse roll coater or the like can be adopted. Also,
The coating amount is 50 to 150 g / m ² in terms of dry adhesion amount (adhesion amount as a water absorbing layer).

As a method of providing a cover cloth on the surface of the water absorbing layer, from the viewpoint of increasing the peel strength between the water absorbing layer and the cover cloth, after coating the composition for forming a water absorbing layer and before drying treatment of the coating film. In addition, it is preferable to employ a so-called wet laminating method in which a tape material (support / sealing layer / wet coating film) and a cover cloth are bonded together.
Here, the peel strength between the water absorbing layer and the cover cloth is 2
It is preferably 0 gf / 25 mm or more, more preferably 30 gf / 25 mm or more.

According to the above-mentioned production method, the low-viscosity water-absorbing layer-forming composition is not applied directly to the support surface, but is applied to the surface of the sealing layer formed on the support surface. Since the water absorbing layer is formed, it is possible to reliably prevent the binder component contained in the composition from leaking through the support in the step of applying the water absorbing layer forming composition. As a result, a rubber-based binder can be contained as a constituent component of the water-absorbing layer in an amount necessary for fixing and holding the water-absorbent resin particles and ensuring adhesiveness with the support or the cover cloth.

[Method of Mounting Water-Proof Tape] The water-proof tape of the present invention is mounted on an optical fiber cable by being wound around the peripheral surface of the rod (13) in the same manner as the water-proof tape 14 shown in FIG. It

Further, the water-absorbing layer is provided with a water-absorbing layer having a very high content ratio of the water-absorbing resin particles and a very low ratio of the binder inhibiting the swelling of the water-absorbing resin particles (2 to 10 parts by weight per 100 parts by weight of the water-absorbing resin particles). According to the water-stop tape of the present invention, a high swelling pressure (void filling property) is obtained by water absorption, and the amount of water-absorbent resin particles (swelling particles) that separate from the water-absorbing layer and move into the groove in the groove of the rod is also obtained. Since the number of the tapes increases, the water blocking effect is superior to that of the conventional tape.

Moreover, since the water-absorbent layer contains the isocyanate compound in a specific ratio, the water-absorbent resin particles are surely fixed and held in the water-absorbent layer despite the low binder content. As a result, it is possible to reliably prevent the water-absorbent resin particles from falling off during cutting and construction of the water blocking tape. Further, the water absorbing layer containing the isocyanate compound has good adhesiveness to the support (sealing layer) and the cover cloth.

Although one embodiment of the water blocking tape of the present invention has been described above, the present invention is not limited to these embodiments and various modifications can be made. For example, a sealing layer and a water absorbing layer may be formed on both surfaces of the support, respectively. Further, the water blocking tape of the present invention can be suitably used not only for optical fiber cables, but also for waterproofing measures (waterproofing measures) of various communication cables and power cables.

[0054]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited thereto. In the following, "part" means "part by weight".
Further, in the following Examples and Comparative Examples, as the non-woven fabric constituting the support, polyester spun-bonded non-woven fabric “Marix 7045” (manufactured by Unitika Ltd .: Mitsuke 4)
5 g / m ² ], and as the non-woven fabric composing the cover cloth, polyester spun-bonded non-woven fabric “Elves S0153 WGE” [manufactured by Unitika Ltd .: basis weight 15 g /
m ² ].

Example 1 (1) Preparation of Composition for Forming Sealing Layer: 100 parts of butyl rubber (rubber-based binder) and 300 parts of calcium carbonate (average particle diameter 2.5 μm) were kneaded with a roll. The obtained rubber composition was dissolved in 300 parts of toluene to give a viscosity (25
A composition for forming a sealing layer having a porosity of 300 poise was prepared.

(2) Preparation of composition for forming water-absorbing layer: 2 parts of butyl rubber (rubber-based binder), 100 parts of water-absorbing resin particles "Aqualic CS-6" (manufactured by Nippon Shokubai Co., Ltd.), and diphenylmethane diisocyanate ( 1 part of an isocyanate compound and 1 part of an anionic surfactant "Nikkor OTP-100" (manufactured by Nikko Chemicals Co., Ltd.) are dissolved in about 100 parts of toluene to give 20 poise (25
A composition for forming a water absorbing layer having a viscosity adjusted to (° C.) was prepared.

(3) Production of waterproof tape: The composition for forming a sealing layer was applied to the surface of a support made of a non-woven fabric, and a coating film was applied
By drying at 00 ° C. for 5 minutes, a sealing layer (weight per unit area: 20 g / m ² ) was formed on the surface of the support. Then, the water-absorbing layer forming composition is applied to the surface of the formed sealing layer,
After laminating a cover cloth made of a non-woven fabric by a wet laminating method, a coating film of the composition for forming a water-absorbing layer
By drying at 0 ° C. for 5 minutes to form a water absorbing layer (100 g / m ^{2 of} basis weight), a support, a sealing layer, a water absorbing layer,
A water blocking tape of the present invention having a thickness of 0.35 mm, which is composed of a cover cloth, was produced.

<Examples 2 to 9> The same as Example 1 except that the amounts of butyl rubber and / or isocyanate compound used were changed and the amounts of toluene used were changed according to the formulation shown in Table 1 below. In the same manner as in Example 1 except that a water-absorbing layer-forming composition having a viscosity adjusted to 20 poise (25 ° C.) was prepared, and each of the prepared water-absorbing layer-forming compositions was used, The water blocking tape of the present invention was produced.

Comparative Example 1 A water absorbing layer forming composition having the same composition as that prepared in Example 7 was prepared according to the formulation shown in Table 2 below, and this water absorbing layer forming composition was used as a support made of a nonwoven fabric. When it was directly applied to the surface of the composition, the organic solvent and the binder component in the composition permeated the support and leaked out, making it impossible to produce a tape.

Comparative Example 2 A water absorbing layer forming composition having the same composition as that prepared in Example 8 was prepared according to the formulation shown in Table 2 below, and the water absorbing layer forming composition was used as a support made of a nonwoven fabric. When it was directly applied to the surface of the composition, the organic solvent and the binder component in the composition permeated the support and leaked out, making it impossible to produce a tape.

Comparative Example 3 A water absorbing layer forming composition having the same composition as that prepared in Example 9 was prepared according to the formulation shown in Table 2 below, and this water absorbing layer forming composition was used as a support made of a nonwoven fabric. When it was directly applied to the surface of the composition, the organic solvent and the binder component in the composition permeated the support and leaked out, making it impossible to produce a tape.

Comparative Example 4 A water blocking tape for comparison was produced in the same manner as in Example 1 except that a composition for forming a water absorbing layer was prepared according to the formulation shown in Table 2 below without using an isocyanate compound. did.

Comparative Example 5 Same as Example 1 except that the amount of butyl rubber used was changed to 5 parts and a water absorbing layer forming composition was prepared without using an isocyanate compound according to the formulation shown in Table 2 below. Then, a water blocking tape for comparison was manufactured.

Comparative Example 6 A comparative example was prepared in the same manner as in Example 1 except that the amount of the isocyanate compound used was changed to 30 parts to prepare a water absorbing layer forming composition according to the formulation shown in Table 2 below. Water-stop tape was manufactured.

Comparative Example 7 A water absorbing layer forming composition was prepared according to the formulation shown in Table 2 below, except that the amount of butyl rubber was changed to 5 parts and the amount of isocyanate compound was changed to 30 parts. A waterproof tape for comparison was manufactured in the same manner as in Example 1.

Comparative Example 8 Same as Example 1 except that the amount of butyl rubber used was changed to 20 parts and a composition for forming a water absorbing layer was prepared without using an isocyanate compound according to the formulation shown in Table 2 below. Then, a water blocking tape for comparison was manufactured.

Comparative Example 9 The procedure of Example 1 was repeated except that the amount of butyl rubber used was changed to 20 parts to prepare a water-absorbing layer-forming composition according to the formulation shown in Table 2 below.
A water blocking tape for comparison was manufactured.

Comparative Example 10 Except that the amount of butyl rubber was changed to 20 parts and the amount of isocyanate compound was changed to 5 parts according to the formulation shown in Table 2 below to prepare a composition for forming a water absorbing layer. A waterproof tape for comparison was manufactured in the same manner as in Example 1.

<Evaluation Test of Water-Proof Tape> Example 1 above
9 to 9 and each of the water blocking tapes obtained in Comparative Examples 4 to 10, the following items were tested to evaluate the performance. The evaluation results are also shown in Tables 1 and 2.

(1) Winding workability: A water blocking tape was wound around a glass rod (pseudo cable) having a diameter of 25 mm to evaluate workability. As an evaluation criterion, when the processing could not be performed due to peeling of the water-absorbing layer or the dropping of the water-absorbing resin particles, it was possible to wind, but when it was extremely difficult to process due to lack of flexibility, “B” was given, and “O” was given when the work could be performed without these problems.

(2) Peeling force of the cover cloth: A waterproof tape was cut into a size of 25 mm × 300 mm to prepare a test piece, and a peeling force (gf) of the cover cloth was measured using a tensile tester at a pulling speed of 200 mm / min. / 25 mm) was measured.

(3) Water absorption / withdrawal amount: Water-stop tape 5 cm ×
A test piece was prepared by cutting it into 5 cm, and 0.2 ml of artificial seawater was injected into the water absorbing layer of this test piece. After 5 minutes, the water absorbing resin particles (swelling particles) that had permeated the cover cloth and moved to the surface were scraped. The water-absorbent resin particles were weighed off.

(4) Water absorption capacity: About 1 g of water-stop tape was precisely weighed (weight at this time is A), and this water-stop tape was 2
It was immersed in artificial seawater at 0 ° C. After the lapse of 10 minutes, the water blocking tape was taken out and weighed (the weight at this time is B ₁ ), and the water absorbing resin particles separated from the water absorbing layer of the water blocking tape and transferred to the artificial seawater were filtered. Separately collected and weighed (the weight at this time is B ₂ ), the water absorption capacity (W) was calculated according to the following formula.

[0074]

[Equation 1]

(5) Running distance: FIG. 4 (a) is a front view of the apparatus used to measure the running distance.
6B is a sectional view taken along line AA in FIG. This device is made of synthetic resin plate 20 (width 10 cm, length 20 m).
10 optical fiber tape cores (8 cores) P are stacked in each of the grooves 21 to 25 (width 3.0 mm, depth 4.5 mm) formed so as to extend in the longitudinal direction, and then,
A water blocking tape T is placed with the cover cloth facing the groove side (lower side) so as to close the grooves 21 to 25, and the synthetic resin plate 28 (width 10 cm, long length) is placed on the water blocking tape T. 20 m) is mounted and fixed. The liquid tightness between the synthetic resin plates (20, 28) is ensured by providing the side plates 26, 27 extending in the longitudinal direction. Using the device having such a configuration, it is partitioned by the synthetic resin plates (20, 28) and the side plates 26, 27 that are arranged to face each other, and is inside the device inner path S in which the water blocking tape T is housed (mounted). A pipe 29 is connected to one end 20A of the device so as to communicate with each other.
Was connected, and artificial seawater was made to infiltrate into the device internal passage S from this pipe 29. Here, the artificial seawater pressure is 0.1 kgf /
It was set to cm ² . After maintaining this state for 24 hours, the device was disassembled, and the distance (running distance) of the artificial seawater that moved in the internal passage S of the device from one end 20A to the other end 20B of the device was measured.

(6) Surface condition of water absorbing layer: Each of the water absorbing layer forming compositions prepared in Examples 1 to 9 and Comparative Examples 4 to 10 was applied to the surface of the sealing layer, and then a cover cloth was applied. Without pasting, the coating film is dried and the water absorption layer
g / m ² ) was formed, and the surface state of the water absorbing layer was visually observed. As the evaluation criteria, “Δ” was given when streaky scratches or irregularities were formed on the surface, and “◯” was given when these defects were not observed and the surface was homogeneous and smooth.

[0077]

[Table 1]

[0078]

[Table 2]

As is clear from the results shown in Table 1, the water blocking tapes of Examples 1 to 10 have good wrapping workability, and the water absorbing layer and the cover cloth constituting the tape adhere to each other. The property was also good. Furthermore, Examples 1-10
The water-stop tape according to (1) had excellent water absorption performance / water stop performance.

On the other hand, in Comparative Examples 1 to 3 in which the water absorbing layer forming composition was directly applied to the surface of the support, the water blocking tape could not be produced. In addition, the water blocking tapes according to Comparative Examples 4 to 5 obtained by using the composition for forming a water absorbing layer containing no isocyanate compound have adhesiveness between the water absorbing layer forming the tape and the cover cloth. Further, the water blocking tape according to Comparative Example 4 was poor in winding workability, and the water absorbing layer of the water blocking tape had poor surface smoothness. Further, in the water blocking tapes according to Comparative Examples 6 to 7 obtained by using the water absorbing layer forming composition containing the isocyanate compound in excess, the water absorbing layer is embrittled in all of the winding processability. It was inferior. In addition, the water blocking tapes according to Comparative Examples 8 to 10 obtained by using the water absorbing layer forming compositions having an excessively large content of butyl rubber were inferior in water absorbing performance and water blocking performance.

[0081]

The water-stop tape of the present invention has a very high proportion of water-absorbent resin particles contained in the water-absorbent layer and a very low proportion of a rubber-based binder which inhibits the swelling of the water-absorbent resin particles. It is possible to obtain a better waterproof effect than that of the tape. Moreover, since the water-absorbent layer contains an isocyanate compound, the water-absorbent resin particles are firmly fixed and held in the water-absorbent layer, and the water-absorbent layer has good adhesiveness to the support and the cover cloth. Will have.

Further, since the water blocking tape of the present invention has the sealing layer formed on the surface of the support, the binder component in the water absorbing layer forming composition does not leak from the support during the production stage. Absent.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a cross-sectional structure of an optical fiber cable.

FIG. 2 is an explanatory diagram showing an example of a cross-sectional structure of a conventional waterproof tape.

FIG. 3 is an explanatory view showing an example of a cross-sectional structure of the water blocking tape of the present invention.

FIG. 4A is a front view of an apparatus used for measuring a running distance, and FIG. 4B is a sectional view taken along line AA in FIG.

[Explanation of symbols]

1 support 2 stop layers 3 water absorption layer 4 cover cloth 11 Tensile body 12 grooves 13 rod 14 Water stopping tape 15 Skin material 16 Optical fiber cores 17 Support 18 Water absorption layer 19 cover cloth 20 synthetic resin plate 21-25 groove 26,27 side plate 28 Synthetic resin plate 29 plumbing

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Naoki Okada 1440 Rokuzaki, Sakura City, Chiba Prefecture Fujikura Sakura Factory (56) References JP-A-5-174636 (JP, A) JP-A-4-222261 (JP, A) JP-A-2-207410 (JP, A) JP-A-2-183911 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02B 6/44

Claims (3)

(57) [Claims] 1. A support comprising a woven or non-woven fabric (1)
And a sealing layer (2) formed on the surface of the support (1)
And a water absorbing layer (3) formed on the surface of the sealing layer (2)
A water-blocking tape comprising: the sealing layer (2), wherein 100 parts by weight of a rubber binder and 50 to 40 of an inorganic filler having a particle diameter of 1 to 10 μm.
The water absorbing layer (3) contains 100 parts by weight of water absorbing resin particles, 2 to 10 parts by weight of a rubber binder, and 0.5 to 20 parts by weight of an isocyanate compound. A water-stop tape characterized by 2. A support (1) made of a woven or non-woven fabric.
100 parts by weight of the rubber-based binder and the particle size
50 to 400 parts by weight of an inorganic filler having a size of 1 to 10 μm,
A composition containing an organic solvent is applied and the coating film is dried to form a sealing layer (2). On the surface of the sealing layer (2), 100 parts by weight of water-absorbent resin particles and a rubber binder are formed. 2 to 10 parts by weight, 0.5 to 20 parts by weight of an isocyanate compound, and an organic solvent, 2
Apply a composition having a viscosity at 20C of 5 poise or less,
A water blocking tape obtained by forming a water absorbing layer (3) by drying a coating film. 3. The water blocking tape according to claim 1, wherein a cover cloth (4) is provided on the surface of the water absorbing layer (3).