JP2004222497A - Water stop material for underground buried cables with protective tube, and the water cut-off method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the water stop material for underground buried cables with a protective tube and the water stop method having excellent water stop performance over a long period even against ground water and sea water to be mounted by a simple method. <P>SOLUTION: This water stop material for underground buried cable with a protective tube is a tape-shaped and/or belt-shaped structural body sealed with nonionic water absorptive resin and/or cationic water absorptive resin by a METSUKE quantity of 500 to 5000 g/m<SP>2</SP>in a sheath material partly having water permeability, the structural body makes its thickness 0.1 to 5cm, its width 0.3 to 30cm, and its length 0.1 to 100m. In this invention, core materials for water cut-off and the water stop method used for these materials for water stop are included. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a water stopping material and a water stopping method for an underground cable with a protection tube.

In recent years, the number of cases where cables such as power cables and optical fiber cables are buried underground has increased. These cables are usually inserted and buried in protective tubes such as vinyl chloride, plastic, and metal pipes.However, groundwater or the like often enters the tubes due to joints in the protective tubes or cracks in the protective tubes. If water accumulates in the protection tube or manhole, the water in the protection tube will enter the manhole even if the water in the manhole is pumped up during cable inspection and repair. There are problems such as requiring labor and time, and the necessity of sequentially discharging and treating water constantly entering the manhole as sewage.
Therefore, (i) a method of providing mortar or rubber packing between the cable and the protection tube immediately before the exit to the manhole to prevent water from entering the manhole. (ii) a method of using a water-swellable urethane as a packing, (iii) a method of inserting a hydrophilic urethane prepolymer and a curing agent into a gap between a pipe and a cable and curing the inside, and (iv) an expansion rate of 8 times or more. Using a plate-like water-swelling material obtained by compressing water-absorbing fibers and the like (for example, Patent Document 1), (v) wrapping a sheet in which a water-absorbent resin is sandwiched between cloths around a cable to fill a gap with a protective tube In addition, a method of preventing water from entering a manhole (for example, Patent Document 2) has been proposed.
JP-A-6-292320 JP-A-10-051935

However, in the method (i), the mortar is often cracked and cannot have a water stopping performance, or a gap is formed between the packing and the protective tube and the cable, so that the leakage does not stop and water is deposited in the manhole in many cases. Further, in the method (ii), since the water-swellable urethane has several days until it swells and the water can be stopped, the time until the water is stopped is too long, and the size of the cable or the protective tube is usually reduced. There is a problem that the size of the water-swellable urethane needs to be adjusted according to the actual protective tube or cable because it is not standardized. In the method of (iii), usually, water is always present in the protective tube, and water is generated during curing, and the gap cannot be completely filled. was there.
Furthermore, in the method of (iv), (v), since the water-absorbing fiber and the water-absorbing resin mainly using a normal anionic system are used, although the initial water stoppage is good for normal groundwater, The water-absorbing resin is highly crosslinked over time due to polyvalent metal ions such as Ca, Mg, and Fe contained in the groundwater over a long period of time, and the amount of absorbed resin is significantly reduced, and water leakage gradually occurs. There was a problem that occurred. In addition, in places close to the coastline or in the past, such as reclaimed land, seawater containing a large amount of Ca and Mg ions or water close to seawater enters the protective tube in the usual anionic monomer configuration. A water-absorbing fiber or resin mainly composed of components has a problem that the swelling amount is insufficient and the water stopping property is insufficient even in the initial stage.

The present inventors have conducted intensive studies in order to obtain a water-stopping material that has improved the above-mentioned problems. As a result, a tape-shaped and / or belt-shaped water-stopping material in which a predetermined amount of a specific water-absorbent resin is sealed causes the above-mentioned problems. It has been found that almost complete water stoppage is possible without any problem, and the present invention has been reached.
That is, according to the present invention, the cationic water-absorbing resin and / or the nonionic water-absorbing resin have a basis weight of 500 to 5000 g / m ² (excluding 4000 g / m ² or less) in the exterior material having at least a part of water permeability. A tape and / or band-like structure enclosed in an amount, the structure having a thickness of 0.1 to 5 cm, a width of 0.3 to 30 cm, and a length of 0.1 to Waterproofing material for underground buried cable with protective tube of 100 m; At least a part of the water-permeable exterior material contains a cationic water-absorbing resin (a crosslinked copolymer of acrylamide and acryloyloxyethyltrimethylammonium chloride. And a nonionic water-absorbing resin (containing sodium acrylate) except that the amount of acrylamide is 34.88 to 80% by weight based on the total monomers. Excluding water absorbent resin amount comprising a crosslinked product of 0.8 to 10 wt% of acrylamide polymer), or a cationic water-absorbent resin and a nonionic water-absorbent resin is encapsulated with a basis weight of 1000~4000g / m ² A tape and / or band-shaped structure, wherein the thickness of the structure is 0.1 to 5 cm, the width is 0.3 to 30 cm, and the length is 0.1 to 100 m. Waterproofing material for underground cable with protective tube; At least a part of the water-permeable exterior material contains 500 to 5000 g / m2 of a cationic water-absorbing resin or a cationic water-absorbing resin and a nonionic water-absorbing resin. (Excluding 1000 g / m ² or more), a tape and / or a band-shaped structure, wherein the structure has a thickness of 0.1 to 5 cm and a width of 0.3 to 30 cm. And the length is 0.1 ~ This is a water-stopping material for an underground cable with a protection tube of 100 m; a water-stopping core material and a water-stopping method using these water-stopping materials.

The water-stopping material for underground cable with protection tube of the present invention has the following effects.
(i) The water-stopping material for underground buried cable with protection tube of the present invention has excellent water-stopping performance over a long period of time, which has not been obtained before, even for groundwater, seawater, and the like.
(ii) Since a flexible material is used and the size can be arbitrarily adjusted, the size can be easily adjusted even when the diameter of the protective tube or the diameter of the cable is different. In addition, since the water can swell along the gaps, the formation of the tap water, which has conventionally been likely to occur, can be prevented by the swelling.
(iii) Since water can be stopped by swelling the material using water in the protective tube, simply setting it at the initial stage, no matter when water enters the protective tube, A water stopping effect can be exhibited.
(iv) Further, by using a core material or the like, it is possible to sufficiently cope with water stoppage of a CVT cable having a plurality of cables in one protective tube.
(v) It can be used in a simple way as a waterproof material for underground cable with protection tube.
(vi) By using the water stopping method of the present invention, it is possible to greatly reduce the time and cost of drainage in manholes and the like that required enormous time and cost when replacing cables in the past.
That is, even when the water that has entered the cable protection tube reaches the water-stopping material of the present invention even if the water or seawater contains a polyvalent metal salt, the nonionic and / or cationic water-absorbing resin in the water-stopping material becomes By quickly absorbing water and swelling and maintaining the swelling for a long period of time, the gap in the protective tube can be closed, and sufficient water-stopping performance, which has not been obtained conventionally, can be exhibited.

In the present invention, a nonionic and / or cationic water-absorbing resin as a swelling agent is sealed in a packaging material having at least a part of water-permeability in order to stop water.
Examples of the nonionic water-absorbent resin used in the present invention include a crosslinked product of (meth) acrylamide polymer, a crosslinked product of vinyl alcohol polymer, a crosslinked product of ethylene oxide polymer, and polyhydroxyalkyl (2 to 5 carbon atoms) (meth) acrylate. Crosslinked polymer, polyethylene glycol (PEG, molecular weight: 200 to 4000) (meth) acrylate polymer crosslinked product, polymethoxy PEG (PEG molecular weight: 200 to 4000) (meth) acrylate crosslinked polymer, starch crosslinked product, hydroxyethyl cellulose crosslinked Isomers and crosslinked products of copolymers of these nonionic polymers and anionic monomers typified by (meth) acrylic acid (neutralized alkali metal salt) and the like. When using a cross-linked polymer, the anionic component Preferably 10 wt% or less of organic amount and usually water-absorbing resin, more preferably 5 wt% or less. When the content of the anionic component exceeds 10% by weight, the anionic component is gradually cross-linked by polyvalent metal ions contained in groundwater, seawater, etc., causing a decrease in the absorption amount of the water-absorbing resin, and water leakage occurs. There are cases.

  The cationic water-absorbing resin used in the present invention includes dialkylamino (meth) acrylate and its quaternary salt (reacted with alkyl halide or dialkyl sulfate), dialkylaminohydroxyalkyl (meth) acrylate and its quaternary salt, dialkyl Polymer of cationic monomer (a) represented by amino (meth) acrylamide and its quaternary salt, dialkylaminohydroxyalkyl (meth) acrylamide and its quaternary salt, N-alkylaminovinylpyridinium halide, trimethylallylammonium halide and the like Crosslinked product; these cationic monomers (a) and (meth) acrylamide, vinyl alcohol (saponified vinyl acetate), polyhydroxyalkyl (2 to 5 carbon atoms) (meth) acrylate, polyethylene glycol (PEG, molecular weight) (200-4000) (meth) acrylate, cross-linked copolymer with nonionic monomer (b) represented by polymethoxy PEG (PEG molecular weight: 200-4000) (meth) acrylate, etc .; the cationic monomer and the nonion Crosslinked copolymer of an anionic monomer (c) typified by a nonionic monomer and (meth) acrylic acid; and the like.

The ratio of the cationic monomer (a) to the nonionic monomer (b) and the optional anionic monomer (c) in the cationic water-absorbing resin is (a) 20 to 100% by weight / (b) 0 80% by weight / (c) 0 to 10% by weight. When the content of the anionic monomer is 10% by weight or more as in the case of the nonionic water-absorbing resin, the anionic component is gradually crosslinked by polyvalent metal ions contained in groundwater, seawater, etc., and the water-absorbing resin is absorbed. This may lead to a decrease in the volume and water leakage may occur.
Among these nonionic water-absorbent resins and cationic water-absorbent resins, cationic water-absorbent resins have higher absorption amounts to groundwater, seawater, water containing polyvalent metal salts and the like than nonionic water-absorbent resins. As a result, the degree of swelling of the water-stopping material also increases, so that it is possible to quickly stop the water with the same amount of addition, and it is even more preferable since the water-stopping is possible even with a small amount of addition.
In the present invention, these nonionic water-absorbing resins and / or cationic water-absorbing resins may be used alone or in combination of two or more.

The water-absorbing resin may be crosslinked by a conventional method, for example, a polymerizable crosslinking agent having two or more double bonds in the molecule [N, N'-methylenebisacrylamide, trimethylolpropane triacrylate, pentaerythritol triacrylate. A method of adding a copolymer at the time of polymerization of a monomer to obtain a crosslinked product; a reactive crosslinker [polyisocyanate (MDI, TDI, etc.) having two or more functional groups capable of reacting with a monomer or a polymer in a molecule. ), Polyglycidyl compounds (ethylene glycol diglycidyl ether, polyglycerol polyglycidyl ether, glycidyl methacrylate, etc.), polyols (glycerol, polyglycerol, etc.), polyamines (polyethyleneimine, ethylenediamine, tetraethylenepentamine, etc.)] A method of adding at an optional stage before, after polymerization or after preparing an uncrosslinked polymer and heating as necessary to obtain a crosslinked product; For example, a method of heating at a temperature of at least 130 ° C., preferably at least 130 ° C. to thermally crosslink to obtain a crosslinked product can be exemplified.
The shape of the water-absorbent resin is not particularly limited, but is, for example, granular, granular, granulated, scaly, massive, pearl-like, and the like.
The particle size distribution of the water-absorbent resin particles is not particularly limited either, but is usually 1 to 2,000 microns, preferably 50 to 1000 microns in average particle diameter.

In the present invention, the basis weight of the nonionic and / or cationic water-absorbing resin to be enclosed in the exterior material depends on the thickness and the material of the exterior material, the width of the exterior material, the type of the water-absorbing resin, and the like. It is 500 to 5000 g / m ² , preferably 1000 to 4000 g / m ² . If the basis weight of the water-absorbing resin is less than 500 g, depending on the type of the water-absorbing resin used, the water-stopping material may not swell sufficiently and may not be able to completely stop the water-stopping.
On the other hand, if the basis weight exceeds 5000 g, the water-absorbent resin may spill out of the exterior material, which is uneconomical.

The exterior material used in the present invention needs at least a part having water permeability so that water can contact the water-swellable water-absorbent resin. It is only necessary that water can enter from the gap of the exterior material, but in order to be able to quickly absorb water, at least a part of the exterior material has water permeability, and the water-absorbing resin swells. It is preferable that the material has a wet strength and a flexibility in a wet state to such an extent that the film does not tear even when it is broken. For this reason, fabrics and mesh films are preferred. The ratio of the area of the water-permeable portion to the area of the whole exterior material is at least 25%, preferably at least 50%, particularly preferably at least 75%. If the normal strength of the exterior material is 2 kg / cm or more, preferably 3 kg / cm or more in both length and width, there is no problem in handling. The wet strength (tensile strength after immersion in ion-exchanged water at 25 ° C. for 1 minute) needs to be 0.05 kg / cm or more, preferably 0.1 kg / cm or more.
The fabric is not particularly limited as long as it has the above-mentioned wet strength. Any synthetic fiber (polyester, polyamide, vinylon, acrylic fiber, etc.), semi-synthetic fiber (acetate, rayon, etc.), natural fiber (cotton, All fiber materials, such as silk and wool, and mixtures thereof (such as blended products) can be applied. It may be a woven or non-woven fabric. Examples of the mesh film include a sheet in which a number of fine holes are formed in a sheet of polyethylene, polypropylene, or the like. The size of the hole is not particularly limited as long as it has water permeability, but is preferably 0.1 to 2 mm, particularly preferably 0.1 to 1 mm.

In addition, in order for the water-swellable water-absorbent resin that has absorbed water to expand evenly in the packaging material, the water-absorbent resin is fixed to the exterior material while the amount of resin per area is almost uniformly sandwiched. Therefore, a felt-like nonwoven fabric is particularly preferable among the above-mentioned materials. The felt is generally referred to as felt, such as woven felt, press felt, needle punch felt, and the like, and is described in, for example, "Handbook of Industrial Textile Materials" (Japan Textile Machinery Society, pp. 362 to 381). Things can be used. The weight per unit area of the felt is not particularly limited, but is preferably 50 to 500 g / m ² , and particularly preferably 90 to 300 g / m ² .

In the present invention, there is no particular limitation on the method for producing the water-stopping material, as long as the water-absorbing resin can be sealed in a predetermined amount and the size of the structure can be set to the predetermined size. Preferred examples include those obtained by adding a water-absorbent resin between sheets of a desired size and cutting to a predetermined size as necessary, and those obtained by adding and enclosing a water-absorbent resin in a bag-shaped exterior material of a predetermined size. Can be.
In addition, the water-stopping material of the present invention is such that the water-absorbent resin is not pushed out of the water-stopping material even after swelling, so that at least the opening in the length direction of the water-stopping material is closed with the resin sandwiched. Is desirable.
Examples of the method of preventing the water-absorbent resin from being extruded during swelling include, for example, a method of heat-sealing some or all of the fibers constituting the fabric of the opening into a heat-sealing fiber, a method of sewing, a method of hot melt, and the like. Examples include a method of using an adhesive, a method of sandwiching the opening with a film-like material and fixing with a heat seal or an adhesive, and a method of attaching the opening with sewing or the like using a hem so as to wrap the opening. As long as the resin is not extruded after water absorption and swelling, any method may be selected. However, in order to almost completely prevent the water absorbent resin from being extruded, hemming is more preferable.
The material of the hem at this time is not particularly limited, but is preferably a material having wet strength and flexibility in a wet state to such a degree that the hem does not break even when swollen with water. For this reason, the above-mentioned cloth, mesh film and spun bond are preferred. Particularly, spunbond is preferable.
Further, the water-stopping material of the present invention is partially formed by a method such as needle punching or heat sealing between the exterior materials in a state where the water-swellable water-absorbent resin is almost uniformly added to the exterior materials. It is also possible to fix and prevent the flow and uneven distribution of the water-absorbent resin in the exterior material, and to expand the water-absorbent resin evenly in the sheet when absorbing water.

From the viewpoint of workability, the shape of the water-stopping material of the present invention is desirably a tape-like or band-like shape that can be cut into an appropriate size in accordance with the shape of the cross section to be water-stopped.
Regarding the dimensions of the water blocking material, it is usually desirable that the thickness is 0.1 to 5 cm, the width is 0.3 cm to 30 cm, and the length is 0.1 to 100 m. Preferably, the thickness is 0.2 to 3 cm, the width is 0.5 to 20 cm, and the length is 0.5 to 50 m. If the thickness is less than 0.1 cm, a predetermined amount of water-absorbing resin or water-absorbing fiber cannot be added, and the water-stopping effect may be insufficient. In some cases, the gap between the cable and the protection tube may not be filled with the waterproof material.
Regarding the width of the water-stopping material, if the width is less than 0.3 cm, the water-stopping material may be too thin and the water-stopping effect may be insufficient. It is necessary to push in the material, and the workability decreases.
Regarding the length, if the length is less than 0.1 m, the water-stopping material is too short to fill the gap between the cable and the protective tube, and the water-stopping effect becomes insufficient, while if the length exceeds 100 m, the water-stopping material becomes large. Workability in a narrow environment such as a manhole is significantly reduced.

  The water stopping method using the water stopping material of the present invention will be described. Underground cables such as power cables and optical fiber cables are usually protected by protective pipes such as PVC pipes, ceramic pipes, fume pipes, etc. Groundwater (or seawater in some cases) often enters the pipes. The water-stopping material can be wound around the seal portion of the protective tube and used to prevent water from penetrating. However, as shown in FIG. It is more effective to interpose the cable in the gap between the cable and the protective tube for the purpose of preventing water from entering the manhole. The reason is that no matter where the water enters from the protection tube, the water comes into contact with the waterproof material just before the entrance to the manhole, and the water-absorbing resin enclosed in the waterproof material swells and stops. This is because the expansion of the material completely closes the gap between the protective tube and the cable, and can prevent water from entering the manhole.

In the installation method of the waterproofing material described above, since the size of the protective tube and the cable is usually gusset, the waterproofing material before swelling in front of the protective tube is connected to the cable in the manhole as shown in FIG. After winding and cutting the tape or band-shaped waterproof material to a size that can almost fill the gap between the cable and the protective tube, inserting water between the cable and the protective tube provides more complete water blocking Preferred for.
Normally, in order to install the water-stopping material in this manner, it is preferable that the water-stopping material can be used in any size and shape according to the gap, and for that purpose, a tape-shaped or It is desirable that the shape be a belt. If it is in the form of a tape or a band, it can be wound around the cable and cut when it reaches almost the inner diameter of the protective tube. In addition, since the water-stopping material can be made compact by winding a tape-shaped or band-shaped material in a roll shape, the cable can be wound around the cable even in a narrow manhole environment where many cables exist.

As described above, underground cables such as power cables and optical fiber cables are usually protected by protective pipes such as polyvinyl chloride pipes, ceramic pipes, fume pipes, etc. Generally, there are two types of cables: a single cable and a triple cable (common name: CVT, hereinafter referred to as CVT) in which three cables are twisted.
In the case where the number of cables in the protective tube is one, water can be almost completely stopped by the above method. However, in the case of CVT, the water-stopping material is simply wound around the outer periphery of the cable and inserted into the protective tube. In many cases, even if the water blocking material swells, the gap between the protection cable and the cable or the gap between the water blocking material and the cable cannot be completely closed as shown in FIG. May occur.
Therefore, regarding the water stopping of CVT, in addition to winding the water stopping material of the present invention around the cable outer periphery, another water swellable core material or the like that fills the gap is inserted between the cables of the water stopping portion, and then the water stopping material is stopped. It is preferable to wrap the water material around the cable.

The water-swellable core material is not particularly limited as long as it is a water-swellable material similar to the water-stopping material and can fill the gap between the cables and the gap between the cable and the water-stopping material. However, for example, as shown in Fig. 4-1, the water-stopping material according to the present invention is cut into short pieces and wound around each cable to form a core material, and the water-stopping material is wound from the outside thereof. Then, another water-stopping material is wound around the cable after being inserted into the gap between the cables as shown in FIG. 4-2, and a core material to which the water-absorbing resin is added as shown in FIG. In addition, a method of winding the waterproof material after inserting it between the cables can be exemplified.
There is no particular limitation on the size of the core material as long as it is a size that can fill the gap. However, when a core material is used, a core having three sides of a splash slightly larger than the diameter of each cable of the CVT is used. It is preferable to use a core material having a Y-shaped cross section (FIG. 5-1), particularly a three-leaf core material (FIGS. 5-2 and 3), because it has a sufficient water stopping effect and can be installed in a short time. can do. The core material may be solid (for example, FIGS. 5-1 and 5-2) or hollow (for example, FIG. 5-3).
There is no particular limitation on the length of the core material, as long as the desired water-stopping property can be achieved. Therefore, it can be suitably used.

Hereinafter, the present invention will be further described with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
The initial and repeated water absorption tests for the model water and artificial seawater used for the water-absorbent resin and the water-absorbent fiber used in the present invention and the comparative water-stopping material were tested by the following methods. Hereinafter, unless otherwise specified,% indicates mass%.

[Initial and post-repeated absorption of model groundwater]
0.1 g of calcium chloride, 0.05 g of magnesium chloride and 0.05 g of ferrous sulfate were added to 1000 g of ion-exchanged water in a beaker and uniformly dissolved to obtain model groundwater.
After adding 1.00 g of water-absorbent resin or water-absorbent fiber to 1000 g of this model groundwater and stirring for 1 hour using a magnetic stirrer, the swollen water-absorbent resin and fiber were removed using a nylon screen having a 75 μm opening. Separately, excess groundwater was drained, and the weight of the water-absorbent resin and fibers on the nylon screen was measured to obtain the initial absorption amount (g / g) of the model groundwater.
Put the entire amount of the water-absorbent resin or fiber on the nylon screen into a beaker, add 1,000 g of newly created model groundwater, stir for 1 hour, and then use the 75 μm nylon screen to re-swell the water-absorbent resin and fiber. I filtered.
The same operation was repeated 10 times in total, and the absorption amount at the 10th time was taken as the absorption amount (g / g) after the repetition of the model groundwater.

[Initial absorption of artificial seawater and absorption after repetition]
After adding 1.00 g of water-absorbent resin or fiber to 1000 g of commercially available "Aquamarine" (trademark of artificial seawater, manufactured by Yasu Pharmaceutical Co., Ltd.), stirring the mixture for 1 hour using a magnetic stirrer, then opening the opening of 75 μm. The swollen water-absorbent resin and fibers are separated using a nylon screen, and excess groundwater is drained off. The weight of the water-absorbent resin and fibers on the nylon screen is measured to determine the initial absorption amount of artificial seawater (g / g). g).
Put the entire amount of the water-absorbent resin or fiber on the nylon screen into a beaker, further add 1,000 g of newly created artificial seawater, stir for 1 hour, and again use the 75 μm nylon screen to swell the water-absorbent resin and fiber again. I filtered.
The same operation was repeated 10 times in total, and the absorption amount at the 10th time was defined as the absorption amount (g / g) after the repetition of the artificial seawater.

Example 1
996 g of a 50% aqueous solution of acrylamide, 4 g of sodium acrylate, 0.1 g of methylenebisacrylamide and 1000 g of ion-exchanged water were added to a 3 liter adiabatic polymerization tank, and the contents were uniformly dissolved and cooled to 5 ° C.
After the dissolved oxygen was removed by passing nitrogen through the contents, 1 g of a 1% aqueous hydrogen peroxide solution, 2 g of a 0.1% L-ascorbic acid aqueous solution, and 3 g of a 1% azo V-50 aqueous solution (manufactured by Wako Pure Chemical Industries, Ltd.) were added. The polymerization was started.
After 10 hours, the content was taken out, the hydrogel was subdivided with a meat chopper, and dried using a ventilation dryer at 100 ° C., and the dried product was pulverized to 100 to 1000 μm to obtain a nonionic water-absorbent resin (1). ) Got. The initial absorption of the nonionic water-absorbent resin (1) in model groundwater and artificial seawater and the absorption after repetition were measured. Table 1 shows the results.
The nonionic water-absorbing resin (1) was evenly sprayed on a felt-like polyester nonwoven fabric (weight per unit area: 150 g / m ² , thickness: about 1 mm) so as to be 1200 g / m ² . Another nonwoven fabric was placed thereon, and the two nonwoven fabrics were fixed with a needle punch, and then cut into a width of 10 cm and a length of 3 m.
The outer periphery was hemmed using a polyester spun bond (approximately 3 cm in width) to prepare the water-stopping material (A) of the present invention. The thickness of the waterproof material was 4 mm.

Example 2
Performed except that PNVA NA-010 (a water-absorbing resin composed of a cross-linked polymer of N-vinylacetamide, manufactured by Showa Denko KK) was used as the nonionic water-absorbing resin (2) instead of the nonionic water-absorbing resin (1). A water-stopping material (B) of the present invention was prepared in the same manner as in Example 1. The initial absorption amount and the post-repetition absorption amount of the nonionic water-absorbent resin (2) in model groundwater and artificial seawater were measured. Table 1 shows the results.

Example 3
600 g of a 50% aqueous solution of acrylamide, 800 g of a 70% aqueous solution of acryloyloxyethyltrimethylammonium chloride, 0.1 g of methylenebisacrylamide and 600 g of ion-exchanged water were added to a 3-liter adiabatic polymerization tank, and the contents were uniformly dissolved. Cooled to ° C.
After nitrogen was passed through the contents to remove dissolved oxygen, 1 g of a 1% aqueous hydrogen peroxide solution, 2 g of a 0.1% L-ascorbic acid aqueous solution, and 3 g of a 1% azo V-50 aqueous solution were added to initiate polymerization.
After 10 hours, the content was taken out, the hydrogel was subdivided with a meat chopper, and dried using a ventilation dryer at 100 ° C., and the dried product was pulverized to 100 to 1000 μm to form a cationic water-absorbing resin (3). ) Got. The amount of initial absorption of this cationic water-absorbent resin (3) in model groundwater and artificial seawater and the amount of absorption after repetition were measured. Table 1 shows the results.
A water-stopping material (C) of the present invention was prepared in the same manner as in Example 1 except that a cationic water-absorbing resin (3) was used instead of the nonionic water-absorbing resin (1) used in Example 1.

Comparative Example 1
A comparison was made in the same manner as in Example 1 except that the nonionic water-absorbing resin (1) was replaced with an anionic water-absorbing resin (a) (Sunwet IM-5000D, manufactured by Sanyo Chemical Industries, Ltd.). Waterproof material (a) was created. The initial absorption amount and the repeated absorption amount of this anionic water-absorbent resin (a) in model groundwater and artificial seawater were measured. Table 1 shows the results.

Comparative Example 2
Instead of the nonionic water-absorbing resin (1), an anionic water-absorbing single fiber (b) (trade name: Bell Oasis, manufactured by Kanebo Gosen) was used. The initial absorption amount and the repeated absorption amount of this anionic water-absorbing single fiber (b) in model groundwater and artificial seawater were measured. Table 1 shows the results.
Polyester staple fiber (weight per unit area: 300 g / m ² ) and anionic water-absorbing single fiber (b) (weight per unit area: 1200 g / m ² ) are mixed and laminated, and heated and compressed to obtain a water-absorbent nonwoven fabric having a thickness of about 5 mm. Was. This water-absorbent nonwoven fabric was cut into a width of 10 cm and a length of 3 m to prepare a comparative water-stopping material (b).

Comparative Example 3
500 g of a 50% aqueous solution of acrylamide, 500 g of sodium acrylate, 0.1 g of methylenebisacrylamide and 1000 g of ion-exchanged water were added to a 3-liter adiabatic polymerization tank, and the contents were uniformly dissolved and cooled to 5 ° C.
After nitrogen was passed through the contents to remove dissolved oxygen, 1 g of a 1% aqueous hydrogen peroxide solution, 2 g of a 0.1% L-ascorbic acid aqueous solution, and 3 g of a 1% azo V-50 aqueous solution were added to initiate polymerization.
After 10 hours, the contents are taken out, the hydrogel is subdivided with a meat chopper, and dried using a ventilation dryer at 100 ° C., and the dried product is pulverized to 100 to 1000 μm to contain 50% of an anionic component. A comparative water-absorbent resin (c) was obtained. The initial absorption amount and the repeated absorption amount in the model groundwater and artificial seawater of the comparative water absorbent resin (c) were measured. Table 1 shows the results.
A comparative water-stopping material (c) was prepared in the same manner as in Example 1 except that a comparative water-absorbing resin (c) was used instead of the nonionic water-absorbing resin (1).

Using the waterproof materials (A) to (C) of the present invention and the comparative waterproof materials (a) to (c) prepared in Examples 1 to 3 and Comparative Examples 1 to 3, with model groundwater and artificial seawater Of the single cable was performed by the following method. Table 2 shows the results.
[Shutoff test of single cable]
A power cable having an outer diameter of 4 cm and a length of 3 m was inserted into a PVC pipe having an inner diameter of 13 cm and a length of 1 m assuming a protective tube.
The waterproof material was tightly wound while being pressed against the power cable outside the PVC pipe. When the diameter of the wound waterproof material reached about 13 cm, the waterproof material was cut.
Slide the cut waterproof material along the power cable and fix it so that the PVC pipe is vertical using clamps etc. that are inserted exactly into the PVC pipe that assumed the protective tube. The model groundwater was supplied from the upper portion of the PVC pipe at a rate of 1 liter / minute by using a pump.
After the supply of the model groundwater was started, the time during which the groundwater leaking from the lower part of the PVC pipe was completely stopped was defined as the initial stoppage time.
When the water leakage from the lower part stops completely, the supply of model groundwater is reduced to 1 liter / 10 minutes, the supply of model groundwater is continued for 140 hours, and it is checked whether water leakage from the lower part of the PVC pipe occurs again. Was observed. If a water leak occurred, the time was recorded.
Similar tests were performed using artificial seawater instead of model groundwater.

Example 4
The water-stopping material (A) prepared in Example 1 was cut into a length of 30 cm, and the central portion was collected and sewn about every 10 cm. As shown in FIG. 5-2, one side was about 4.5 cm and the width was 10 cm. Was prepared.
A CVT cable in which three power cables each having an outer diameter of 4 cm and a length of 3 m were inserted into a PVC pipe having an inner diameter of 13 cm and a length of 1 m assuming a protective tube.
The core material prepared in Example 4 was sandwiched between three cables inside a PVC pipe. The waterproof material (A) was tightly wound while being pressed against the power cable outside the PVC pipe. When the diameter of the wound waterproof material reached about 13 cm, the waterproof material was cut.
The cut water-stopping material was slid along the power cable, and was inserted exactly into a PVC pipe assuming a protective tube up to a position where the core was inserted between the cables.
Using a clamp or the like, fix the PVC pipe so that it is vertical (the inserted waterproof material is located at the bottom of the PVC pipe), and pump the model groundwater from the top of the PVC pipe at a rate of 1 liter / minute using a pump. Supplied.
After the supply of the model groundwater was started, the time during which the groundwater leaking from the lower part of the PVC pipe was completely stopped was defined as the initial stoppage time.
When the water leakage from the lower part stops completely, the supply of model groundwater is reduced to 1 liter / 10 minutes, the supply of model groundwater is continued for 140 hours, and it is checked whether water leakage from the lower part of the PVC pipe occurs again. Was observed. If a water leak occurred, the time was recorded.
Similar tests were performed using artificial seawater instead of model groundwater.

The following is clear from Tables 1 and 2.
(i) The nonionic water-absorbing resins (1) to (2) and the cationic water-absorbing resin (3) used in the water-stopping material of the present invention are more artificial than the comparative water-absorbing resins (a) to (b). Absorption to seawater is high, and absorption in groundwater and artificial seawater hardly changes over the long term.
(ii) The water-stopping materials (A) to (C) of the present invention can exhibit a stable water-stopping effect without causing water leakage over a long period of time as compared with the comparative water-stopping materials (a) to (c).
(iii) By using a swellable core material in combination, a stable water stopping effect can be exhibited for an underground cable with a protection tube using a CVT cable.

  From the above, the present invention is useful as a water-stopping material for underground buried cables with protective tubes such as power cables and optical fiber cables, a core material for water-stopping, and a water-stopping method.

It is sectional drawing which showed the position where the waterproof material of this invention is installed. It is the key map showing the method of installing the waterproof material of the present invention in a protection tube. It is sectional drawing which installed only the water stop material in the CVT cable. It is sectional drawing which inserted the short piece of the water stop material between CVT cables. It is sectional drawing and a perspective view which showed the structure of the core material, and the insertion method to a CVT cable.

Explanation of reference numerals

1: Manhole 2: Cable protection tube 3: Underground cable 4: Waterproof material 5: CVT cable structure 6: Waterproof material and gap between cable and cable 7: Short piece of waterproof material 8: Core material 9: Exterior Material 10: Water absorbent resin

Claims (12)

A cationic water-absorbing resin and / or a nonionic water-absorbing resin are enclosed in an exterior material having at least a part of water permeability at a basis weight of 500 to 5000 g / m ² (excluding 4000 g / m ² or less). , A protective tube having a thickness of 0.1 to 5 cm, a width of 0.3 to 30 cm, and a length of 0.1 to 100 m. Waterproofing material for underground cable with cable. At least a part of the exterior material having water permeability is provided with a cationic water-absorbing resin (a crosslinked product of acrylamide and acryloyloxyethyltrimethylammonium chloride, wherein the amount of acrylamide is 34. Excluding the cationic water-absorbing resin of 88 to 80% by weight) and nonionic water-absorbing resin (excluding the water-absorbing resin composed of a crosslinked acrylamide polymer having a content of sodium acrylate of 0.8 to 10% by mass) ) Or a tape and / or band-like structure in which a cationic water-absorbent resin and a nonionic water-absorbent resin are enclosed at a basis weight of 1000 to 4000 g / m ² , wherein the thickness of the structure is 0 Waterproofing material for underground buried cable with protective tube having a length of 0.1 to 5 cm, a width of 0.3 to 30 cm, and a length of 0.1 to 100 m. During exterior material having at least partially water permeable, cationic water-absorbing resin, or cationic water-absorbent resin and a nonionic water-absorbent resin, weight per unit area of 500 to 5000 g / m ² (except for 1000 g / m ² or more) A tape and / or band-like structure enclosed in an amount, the structure having a thickness of 0.1 to 5 cm, a width of 0.3 to 30 cm, and a length of 0.1 to 100m waterproof material for underground cable with protective tube. The cationic water-absorbing resin is a crosslinked copolymer of acrylamide and acryloyloxyethyltrimethylammonium chloride, and the amount of acrylamide is 34.88 to 80% by weight based on the total monomers. Waterproof material. The water-stopping material according to claim 3 or 4, wherein the nonionic water-absorbing resin is a water-absorbing resin comprising a crosslinked product of an acrylamide polymer having a content of sodium acrylate of 0.8 to 10% by mass. The water stopping material according to any one of claims 1 to 5, wherein the content of the anionic monomer component in the water absorbent resin is 10% by mass or less. A method for waterproofing an underground cable with a protective tube, wherein the waterproof material according to any one of claims 1 to 6 is interposed between the cable of the cable with an underground cable with a protective tube and the protective tube. 8. The water stopping method according to claim 7, wherein the periphery of the cable is wound with a water stopping material so as to block off between the cable and the protection tube. A method for stopping water of an underground cable having three structures in a protective tube, wherein the water stopping material and the water-swellable core material according to any one of claims 1 to 6 are used together. The core material has a cationic water-absorbing resin and / or a nonionic water-absorbing resin sealed in at least a part of an exterior material having water permeability, and fills a gap between cables and a gap between a cable and a water-blocking material. The method for stopping water according to claim 9, comprising a structure capable of operating. The water stoppage according to any one of claims 7 to 10, wherein a waterstop material is interposed between the cable and the protection tube immediately before the exit of the underground cable to the cable manhole to prevent water from entering the manhole. Method. At least a portion of the water-permeable exterior material contains a cationic water-absorbing resin (a water-absorbing resin composed of acrylamide and acryloyloxyethyltrimethylammonium chloride, wherein the amount of acrylamide is 34.88 to 80 with respect to the total monomer). Excluding the cationic water-absorbing resin of which weight percent is included) and / or nonionic water-absorbing resin (excluding the water-absorbing resin composed of a crosslinked acrylamide polymer having a sodium acrylate content of 0.8 to 10% by mass) ), Wherein the core section for underground buried cable having three structures in the protective tube is characterized in that the cross-section in which is enclosed is a Y-shaped or three-lobed structure.