JP3389049B2 - 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, and a water absorbing layer 18 formed on the surface of the support 17.

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 a part of the water-absorbent resin leaves the water-absorbent layer 18 and moves to the outside, where it is filled in a gap in the cable and has a water-stopping effect. Exert. This water absorption layer 1
8 is formed by applying a composition containing water-absorbent resin particles, a binder, and an organic solvent on the surface of the support 17 and drying the coating film to remove the organic solvent.

The waterproof tape 14 having the cross-sectional structure as shown in FIG. 2 has the water absorbing layer 18 inside (the groove 12 side),
It is mounted by being wound around the rod (13).

In the optical fiber cable having the structure shown in FIG. 1, when the outer cover member 15 is damaged and water enters the cable from there, the water-absorbing layer of the water-stop tape 14 wound around the position corresponding to the damaged part ( 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.

[0008]

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 absorbing layer is low, for example, 10 parts by weight or less per 100 parts by weight of the water absorbing resin particles, the water blocking tape having such a water absorbing layer has the following content. 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 production and construction of the waterproof tape. .

(3) 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.

(4) In the step of forming the water absorbing layer, in order to improve the coating characteristics 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 a water blocking tape), or the resulting water blocking tape is prone to the problems (1) and (2).

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 having a water absorbing layer having good adhesiveness to a support. 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. A fifth object of the present invention is to provide a water blocking tape in which a binder component for forming a water absorbing layer does not leak from a support in a manufacturing stage.

[0015]

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-absorbing layer (3) contains 100 parts by weight of water-absorbing resin particles and 2 to 10 parts by weight of a rubber-based binder, and 50% by weight or more of the water-absorbing resin particles is 10 parts by weight. The water-absorbent resin particles having a particle size of ˜50 μm and having a particle size exceeding 100 μm are substantially not contained.

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),
On the surface of the sealing layer (2), 50% by weight or more is 10-5.
100 parts by weight of water-absorbent resin particles having a particle size of 0 μm and substantially not containing particles having a particle size exceeding 100 μm,
A composition containing 2 to 10 parts by weight of a rubber-based binder and an organic solvent and having a viscosity of 20 poise or less at 25 ° C. [hereinafter, also referred to as a “water absorbing layer forming composition”. ] And the coating film is dried to form a water absorbing layer (3).

[0017]

[Action]

[1] 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. Further, particles having a small diameter (10 to 50 μm), which account for 50% by weight or more of the water-absorbent resin particles, have a large contact area with water and thus have a high swelling speed. Furthermore, the swelling particles derived from the small-diameter water-absorbent resin particles can penetrate into the minute gaps in the cable, and have excellent void filling properties. As a result, as is clear from the results of the examples described below, the water blocking tape of the present invention can exhibit a water blocking effect superior to that of the conventional tape.

[2] 50% by weight or more of the water-absorbent resin particles dispersedly contained in the water-absorbent layer are particles having a particle diameter of 10 to 50 μm, and the water-absorbent resin particles (aggregate) containing such small-diameter particles. Has a small volume per unit weight and thus is well compatible with the binder. Therefore, the water-absorbent resin particles can be securely fixed and held by a small amount of the rubber-based binder.

[3] "Excellent sticking / holding property due to binder" and "excellent water blocking performance due to water absorbing resin particles" are
It is exhibited for the first time by controlling the content ratio of the binder in the water absorbing layer and the particle size of the water absorbing resin particles. That is, when the content ratio of the binder in the water absorbing layer is high (when it exceeds 10 parts by weight per 100 parts by weight of the water absorbing resin particles), the water absorbing resin particles having a small diameter (10 to 50 μm) are buried in the binder, Contact between the water-absorbent resin particles and water is hindered, and water-stopping performance is significantly reduced. In addition, even if the content ratio of the binder is reduced, if the water-absorbent resin particles having a small diameter are not contained at a constant ratio,
There is a problem that the water-absorbent resin particles fall off during cutting and construction of the water blocking tape. By lowering the content ratio of the binder and containing a small diameter of water-absorbent resin particles at a constant ratio, the water-absorbent resin particles are not embedded in the binder and are fixedly held in a state where some of the small-diameter particles are exposed. It As a result, excellent sticking and holding performance and water stopping performance are exhibited in good balance.

[4] A water-absorbing layer having a low binder content and a small proportion of water-absorbing resin particles having a small diameter has a high apparent density (small porosity). The waterproof tape provided has good workability because of its small thickness.

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

[6] Since the sealing layer is formed on the surface of the support, even if a water absorbing layer forming composition having a low viscosity is applied at the production stage, the binder component in the composition permeates the support. The water-absorbent resin particles having a small diameter (particles having a size of 10 to 50 μm) do not leak.

[0023]

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. It is composed by.

[Support] As the support (1) constituting the waterproof tape of the present invention, a synthetic fiber such as polyester or nylon, which is not broken by the tension when wound around the rod and is 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 ratio 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) by forming a sealing layer on the surface of a support. Even in this case, it is possible to reliably prevent the binder component in the composition from permeating the support and leaking out. Furthermore, it is possible to prevent small-diameter water-absorbent resin particles (particles of 10 to 50 μm), which account for 50% by weight or more of the water-absorbent resin particles, 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 and a rubber binder.

The water-absorbent resin particles constituting the water-absorbent layer include
Being made of a synthetic resin that is insoluble in water and not decomposed by microorganisms, has a specific particle size distribution, and has a weight of 30-
It can be selected from the synthetic resin particles that satisfy the conditions such that about 1000 times as much water is absorbed to form swollen particles.

Specific examples of the synthetic resin constituting the water-absorbent resin particles include acrylic acid-based crosslinked products, saponified vinyl acetate-acrylic acid ester copolymers, and reaction products of polyvinyl alcohol and maleic anhydride. Polyvinyl alcohol-maleic acid copolymer cross-linked product, acrylic acid salt-acrylamide copolymer, polyethylene oxide modified product, isobutylene-maleic anhydride copolymer cross-linked product, sulfoalkyl acrylate-acrylic acid copolymer Examples thereof include crosslinked products, and these can be used alone or in combination of two or more kinds.

In the water blocking tape of the present invention, 50% by weight or more, preferably 55% by weight or more of the water absorbing resin particles contained in the water absorbing layer have a particle diameter of 10 to 50 μm, and The layer does not substantially contain water-absorbent resin particles having a particle size of more than 100 μm. Here, "substantially not contained" means that the proportion of the water-absorbent resin particles is less than 3% by weight.

When the proportion of small particles having a particle diameter of 10 to 50 μm is less than 50% by weight, particularly when the proportion of particles having a particle diameter of more than 50 μm is large, a small amount of a rubber binder is used. The particles cannot be sufficiently fixed and held, and the water-absorbent resin particles are likely to fall off during cutting and construction of the water blocking tape. Further, when the occupancy ratio of the fine particles having a particle diameter of less than 10 μm is large, the fine particles are buried in the rubber-based binder, and the water blocking performance is significantly deteriorated. The particle size is 1
It is extremely difficult to fix and hold the water-absorbent resin particles having a diameter of more than 00 μm with a small amount of a rubber-based binder, and it is necessary that such particles having a large diameter are not contained.

Examples of the rubber-based binder forming the water-absorbing layer include those exemplified as the binder forming the sealing layer. Of these, synthetic rubber containing no halogen atom is preferable, and butyl rubber is particularly preferable. It is a blend rubber of ethylene propylene rubber and butyl rubber / ethylene propylene 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 the water-stop tape including the water-absorbent layer, the water-absorbent resin particles may fall off or the surface of the support (sealing layer surface)
Causes the peeling of the water absorption layer. On the other hand, when the content ratio of the rubber-based binder exceeds 10 parts by weight, small-diameter water-absorbent resin particles (particles of 10 to 50 μm) are buried in the rubber-based binder, and the water-absorbent resin particles come into contact with water. Is impeded, and the water stopping performance is significantly reduced.

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. The content ratio of the antioxidant is
The amount is 0.2 to 2 parts by weight per 100 parts by weight of the water absorbent resin particles.

[Method for producing water-stop tape] The water-stop tape of the present invention can be produced by forming a waterproof layer on the surface of a support and forming a water-absorbing layer on the surface of the waterproof layer. .

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 the 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 water-absorbing layer-forming composition containing water-absorbent resin particles, a rubber-based binder, and an organic solvent to the surface of the sealing layer and drying the coating film.

The organic solvent contained in the composition for forming a water absorbing layer is not particularly limited as long as it can dissolve the rubber binder contained in the composition, and it is not specifically limited. Specifically, the organic solvents exemplified as those contained in the sealing layer forming composition can be mentioned.

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 5 to 100 g / m ² in terms of dry adhesion amount (adhesion amount as a water absorbing layer).

According to the above-mentioned production method, the low-viscosity water-absorbing layer-forming composition is not directly applied to the surface of the support, but is applied to the surface of the sealing layer formed on the surface of the support. Since the water-absorbing layer is formed, the binder component dissolved in the organic solvent is reliably prevented from leaking out through the support in the step of applying the composition for forming a water-absorbing layer. A rubber-based binder in an amount necessary for securing fixation and securing adhesiveness to the support can be contained as a constituent component of the water-absorbing layer. further,
Small-diameter water-absorbent resin particles (particles of 10 to 50 μm), which account for 50% by weight or more of the water-absorbent resin particles, are reliably prevented from leaking out through the support, thereby exhibiting excellent water-stopping performance. A sufficient amount of water-absorbing resin particles can be contained as a constituent component of the water-absorbing layer.

[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-stop tape 14 shown in FIG. It

The content ratio of the water-absorbent resin particles is extremely high, and the ratio of the binder that inhibits the swelling of the water-absorbent resin particles is extremely low (2 to 10 parts by weight per 100 parts by weight of the water-absorbent resin particles). According to the water-stop tape of the present invention, 50% by weight or more of the water-absorbent resin particles are small-diameter particles (particles of 10 to 50 μm) having a high swelling rate and excellent void filling properties. The pressure (void filling property) is obtained, and the amount of water-absorbent resin particles (swelling particles) that leave the water-absorbent layer and move into the gaps in the grooves of the rod is also increased, so that the water-stopping effect superior to that of the conventional tape is achieved. Played.

Moreover, by making the content ratio of the binder low so that the small-diameter water-absorbing resin particles are contained at a constant ratio, the small-diameter water-absorbing resin particles are not buried in the rubber-based binder, and the small-diameter water-absorbing resin is contained. The particles are fixedly held in a state where a part thereof is exposed (a state where contact with water is secured). As a result, excellent sticking and holding performance and water stopping performance are exhibited in good balance.

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.

[0052]

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".

In the following examples and comparative examples, the nonwoven fabric constituting the support is a polyester spunbonded nonwoven fabric "Marix 7060" (manufactured by Unitika Ltd .:
A basis weight of 60 g / m ² ] was used. As the water-absorbent resin particles, "Aqualic CS-6" (manufactured by Nippon Shokubai Co., Ltd.) is sieved to obtain three kinds of water-absorbent resin particles (particle A, particle B, particle C) having different particle size distributions. Prepared. The particle size distribution of these water-absorbent resin particles is as follows, and a more detailed particle size distribution is shown in FIG.

[Particle A] ・ Particle size less than 10 μm: 3% by weight ・ Particle size 10 to 50 μm: 59% by weight ・ Particle size 50 to 100 μm: 38% by weight

[Particle B] ・ Particle size less than 10 μm: 3% by weight ・ Particle size 10 to 50 μm: 45% by weight Particle size 50 to 100 μm: 7% by weight ・ Particle size 100 to 200 μm: 45% by weight

[Particle C] ・ Particle size less than 10 μm: 52% by weight ・ Particle size 10 to 50 μm: 45% by weight Particle size 50 to 100 μm: 3% by weight

<Example 1> (1) Preparation of composition for forming sealing layer: 100 parts of butyl rubber (rubber-based binder) and 200 parts of calcium carbonate (average particle diameter 2.5 μm) were kneaded with a roll. The rubber composition obtained was dissolved in 250 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 (particle A), and anionic surfactant "Nikkor"
2 parts of OTP-100 "(manufactured by Nikko Chemicals Co., Ltd.) in about 100 parts of toluene, and 20 poise (25 ° C)
A composition for forming a water absorbing layer having a viscosity adjusted to 1. 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 to
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,
The coating film is dried at 100 ° C for 5 minutes to obtain a water-absorbing layer (Basis weight 50 g /
m ² ) to form a water-stop tape of the present invention having a thickness of 0.25 mm, which comprises a support, a sealing layer, and a water-absorbing layer.

<Examples 2 to 3> 20 poises were obtained in the same manner as in Example 1 except that the amount of butyl rubber used was changed according to the formulation shown in Table 1 below, and the amount of toluene was changed as necessary. The water-stop tape of the present invention was prepared in the same manner as in Example 1 except that a water-absorbing layer-forming composition having a viscosity adjusted to 25 ° C.) was prepared and each of the prepared water-absorbing layer-forming compositions was used. Was manufactured.

Example 4 The procedure of Example 1 was repeated, except that the amount of toluene used was changed to prepare a water-absorbing layer-forming composition adjusted to a viscosity of 50 poise (25 ° C.). An inventive waterproofing tape was produced.

<Comparative Examples 1 and 2> 20 poises (in the same manner as in Example 1) except that the amount of butyl rubber used was changed according to the formulation shown in Table 2 below, and the amount of toluene used was changed as necessary. A water absorbing layer forming composition having a viscosity adjusted to 25 ° C.) was prepared, and each of the prepared water absorbing layer forming compositions was directly applied to the surface of a non-woven fabric support. It was not possible to produce a tape because the solvent and the binder component leaked out through the support.

<Comparative Examples 3 to 6> 20 poises were obtained in the same manner as in Example 1 except that the amount of butyl rubber used was changed according to the formulation shown in Table 2 below, and the amount of toluene used was changed as necessary. A water blocking tape for comparison was prepared in the same manner as in Example 1 except that a water absorbing layer forming composition having a viscosity adjusted to 25 ° C.) was prepared and each of the prepared water absorbing layer forming compositions was used. Was manufactured.

Comparative Examples 7 to 9 Comparative water blocking tapes were produced in the same manner as in Examples 1 to 3 except that 100 parts of particles B were used as the water absorbing resin particles according to the formulation shown in Table 2 below.

Comparative Examples 10 to 12 Comparative water blocking tapes were produced in the same manner as in Examples 1 to 3 except that 100 parts of particles C were used as the water absorbing resin particles according to the formulation shown in Table 2 below.

<Evaluation Test of Water-Proof Tape> Example 1 above
4 and Comparative Examples 3 to 12, each of the water blocking tapes was tested for the following items 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 the evaluation criteria, "x" was given when the processing could not be performed due to peeling of the water-absorbing layer or falling-off of the water-absorbing resin particles, and "○" was given when the processing could be performed without these problems.

(2) Sticking retention (abrasion amount): A water blocking tape was cut into 3 cm × 22 cm to prepare a test piece, and the weight of the test piece after 100 friction rotations was performed using a Gakushin type friction tester. From the change, the amount of wear (the amount of water absorbent resin particles dropped off) was measured. As the base fabric for friction, a warp yarn and a weft yarn each made of a polyester yarn of 250 denier and having a striking length of 50 yarns / inch were used.

(3) Water absorption / withdrawal amount: Water-stop tape 5 cm ×
A test piece was prepared by cutting it into 5 cm, 0.2 ml of artificial seawater was injected into the water absorbing layer of this test piece, and after 5 minutes, the water absorbing resin particles (swelling particles) transferred to the surface were scraped off using a scraper, The weight of the water-absorbent resin particles was measured.

(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.

[0071]

[Equation 1]

(5) Running distance: FIG. 5 (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).
The optical fiber tape core wire (4 cores) P is housed in each of the grooves 21 to 25 (width 1.5 mm, depth 2.5 mm) formed so as to extend in the longitudinal direction of the groove 21 to
A water blocking tape T is placed with the water absorbing layer facing the groove side (lower side) so as to block 25, and a synthetic resin plate 28 (width 10 cm, length 20 m) is placed on the water blocking tape T. It is configured by mounting and fixing. The synthetic resin plate (2
The liquid tightness between 0, 28) is the side plate 26 extending in the longitudinal direction,
It is ensured by providing 27. Using the apparatus having such a configuration, the synthetic resin plates (20,
28) and the side plates 26, 27, and a pipe 29 is connected to one end 20A of the device so as to communicate with the device internal passage S in which the water blocking tape T is accommodated. Artificial seawater was infiltrated into S. Here, the water pressure of the artificial seawater was set to 0.1 kgf / cm ² . This state is 2
After holding for 4 hours, this 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) Blocking resistance: Water-proof tape 3
10 test pieces were prepared by cutting into cm × 15 cm, and these test pieces were placed in a thermo-hygrostat (temperature: 25 ° C., relative humidity: 85).
%) For 5 hours. Then, the test pieces were taken out from the constant temperature and humidity chamber and laminated to produce a laminated body, and then both sides of the laminated body were sandwiched by glass plates to obtain 50 g.
A compressive load of f / cm ² was applied, and in this state, it was left again in the constant temperature and humidity chamber. After the lapse of 24 hours, the laminated body of the test pieces was taken out from the constant temperature and humidity chamber, the glass plate was removed, and the test pieces were peeled off one by one. As an evaluation criterion, "○" was given when the film could be easily peeled off, and "△" was shown when a little tackiness was observed.

(7) Surface state of water absorbing layer: The surface state of the water absorbing layer of the water blocking tape 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.

[0075]

[Table 1]

[0076]

[Table 2]

As is clear from the results shown in Table 1, the water blocking tapes according to Examples 1 to 4 had good winding workability and good sticking and holding properties. Furthermore, the water blocking tapes according to Examples 1 to 4 had excellent water absorption performance / water blocking performance. In addition, since the water blocking tape according to Example 4 had a high viscosity of the water absorbing layer forming composition used in the manufacturing stage, the water blocking layer of the water blocking tape had poor surface smoothness. It was

On the other hand, in Comparative Examples 1 and 2 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. Further, as is clear from the results shown in Table 2, the water-stop tape according to Comparative Example 3 obtained by using the composition for forming a water-absorbing layer in which the content ratio of butyl rubber was too small, the winding processability, the sticking retention And the surface smoothness of the water absorbing layer were inferior. In addition, the water blocking tapes according to Comparative Examples 4 to 6 obtained by using the water absorbing layer forming compositions having an excessively large butyl rubber content were inferior in water absorbing performance and water blocking performance. Also, the particle size is 50μ
All of the water blocking tapes according to Comparative Examples 7 to 9 in which the water absorbing resin particles (particles B) containing a large amount of particles exceeding m are contained in the water absorbing layer are inferior in sticking retention property, and Comparative Example 7
The water blocking tape according to No. 1 was also poor in winding workability. Further, Comparative Example 1 in which the water-absorbent layer contains water-absorbent resin particles (particles C) containing a large amount of particles having a particle size of less than 10 μm.
All of the water blocking tapes of 0 to 12 were inferior in water absorption performance and water blocking performance.

[0079]

The water-stop tape of the present invention comprises a water-absorbing layer having an extremely high content of water-absorbent resin particles and an extremely low content of binder, and more than 50 water-absorbent resin particles.
Since the weight% or more is a small diameter particle (particle of 10 to 50 μm) having a high swelling rate and excellent void filling property, the water blocking tape of the present invention has a water blocking effect superior to that of the conventional tape. Can be demonstrated.

Further, the water-absorbent resin particles containing small-diameter particles (particles of 10 to 50 μm) in a proportion of 50% by weight or more have a large bulk density and are well compatible with rubber-based binders. Can be fixedly held.

Since the content ratio of the binder in the water absorbing layer is low and the small diameter water absorbing resin particles (particles of 10 to 50 μm) are contained at a constant ratio, the small diameter water absorbing resin particles are contained in the rubber binder. It is fixed and held in a state where a part of the particles is exposed (a state where contact with water is secured) without being buried. As a result, excellent sticking and holding performance and water stopping performance are exhibited in good balance.

Furthermore, since the water blocking tape of the present invention has a sealing layer formed on the surface of the support, the binder component in the water absorbing layer forming composition and the water absorbing resin particles (10 ˜50 μm particles) do not leak out.

[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. 4 is a graph showing a particle size distribution of water-absorbent resin particles used in Examples and Comparative Examples.

FIG. 5A is a front view of an apparatus used for measuring a running distance, and FIG. 5B is a sectional view taken along line AA in FIG.

[Explanation of symbols]

1 support 2 stop layers 3 water absorption layer 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 front page (72) Inventor Naoki Okada 1440 Rokuzaki, Sakura City, Chiba Fujikura Co., Ltd. Sakura Factory (56) References JP-A-2-183911 (JP, A) JP-A-2-207410 (JP, A) JP 4-222261 (JP, A) JP 6-118286 (JP, A) JP 63-241507 (JP, A) (58) Fields investigated (Int. Cl. ⁷⁾ , DB name) G02B 6/44

Claims (2)

(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.
0 parts by weight, the water absorbing layer (3) contains 100 parts by weight of water absorbing resin particles, and 2 to 10 parts by weight of a rubber-based binder, and 50% by weight or more of the water absorbing resin particles. Has a particle size of 10 to 50 μm, and substantially does not contain water-absorbent resin particles having a particle size of more than 100 μm. 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), 50% by weight or more is 10-5.
100 parts by weight of water-absorbent resin particles having a particle size of 0 μm and substantially not containing particles having a particle size exceeding 100 μm,
It is obtained by applying a composition containing 2 to 10 parts by weight of a rubber binder and an organic solvent and having a viscosity of 20 poise or less at 25 ° C. and drying the coating film to form a water absorbing layer (3). A water-stop tape characterized in that