JP2606988B2 - Water-absorbing agent composition and water-stopping material comprising the water-absorbing agent composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-absorbing agent composition mainly used as a water-stopping agent and a water-stopping material having the water-absorbing agent composition supported on a substrate. More specifically, the present invention provides
When water, particularly high-concentration salt water such as seawater enters the sheath of a cable such as a communication cable such as an optical cable or a metal cable or a power cable, the salt water moves in the sheath and deteriorates the cables and various devices. The present invention relates to a water-absorbing agent composition used as a water-stopping agent or the like for preventing the water-absorbing agent, and a water-stopping material having the water-absorbing agent composition supported on a substrate.

[0002]

2. Description of the Related Art When water enters the sheath due to trauma of the sheath of the cable, the water moves quickly in the sheath, and there is a problem that a communication cable such as an optical fiber, a power line, or various devices is deteriorated. . To solve this problem, a method has been proposed in which a water-insoluble and water-swellable water-absorbing agent is inserted into the sheath.

[0003] As such water absorbing agents, there have hitherto been used a crosslinked product of sodium polyacrylate, a neutralized product of a starch-acrylic acid graft copolymer, a saponified product of a vinyl acetate-acrylic acid ester copolymer, isobutylene-maleic anhydride. A product in which a water-absorbing resin such as a neutralized acid copolymer crosslinked product is fixed to a nonwoven fabric or the like is used (JP-A-64-76609).
No., Japanese Utility Model Laid-Open No. 61-129228). However, the water-absorbing agent has a low water-absorbing rate, does not have a sufficient water-absorbing ability with salt water, or has an insufficient gel viscosity of a water-absorbing resin used. However, there is a problem that water cannot be prevented when the cable is buried.

[0004] Further, a water-soluble polymer such as sulfoalkyl (meth) acrylate or acrylamide and a crosslinking agent are impregnated into a base material such as a nonwoven fabric, and then heat-crosslinked to produce a water-absorbing tape having excellent water-stopping property against seawater. (Japanese Patent Laid-Open No. 2-1690). But,
In such a water-stopping tape in which the base material and the water-absorbing resin are firmly integrated, there is a problem that only a tape having a low water-stopping ability can be obtained because the water-absorbing speed is low.

[0005] In order to solve these problems, the present inventors have proposed a specific polymer crosslinked product comprising a specific (meth) acrylamide and a (meth) acrylate (Japanese Patent Application No. Hei 10-214,878). 2-245424). However, since the crosslinked polymer has a high pH, the contacted aqueous liquid becomes alkaline, and there is a problem that the material of the apparatus is corroded during use. On the other hand, by copolymerizing the crosslinked polymer with (meth) acrylic acid, the pH can be lowered, but there is a problem of heat resistance such that the water absorption capacity at high temperatures is reduced.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a sufficient initial water stopping effect even when a high concentration of salt water enters the cable sheath, and a stable water stopping ability for a long period of time. Demonstrate, and the pH is in the neutral range,
An object of the present invention is to provide a water-absorbing composition having excellent thermal stability capable of maintaining performance even at a high temperature, and a water-stopping material containing the water-absorbing composition.

[0007]

SUMMARY OF THE INVENTION The objects of the present invention are to provide at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylic acid salt with (meth) acrylamide. Molar ratio of 1: 9 to 5: 5
(Meth) acrylic acid and (meth) acrylic acid with respect to 100 parts by weight of a crosslinked polymer (A) obtained by polymerizing a monomer mixture comprising the (meth) acrylic compound and the (meth) acrylamide The molar ratio with the salt is 2: 8 to 1
The crosslinked poly (meth) acrylic acid (salt) (B) obtained by polymerizing the (meth) acrylic monomer of 0: 0 is 0.1 to 0.1%.
This is achieved by a water-absorbing agent composition formulated in a range of 50 parts by weight and a water-stopping material having the water-absorbing agent composition supported on a substrate.

[0008]

The water-absorbing composition according to the present invention comprises at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylate, and (meth) acrylic acid.
With respect to 100 parts by weight of a crosslinked polymer (A) obtained by polymerizing the (meth) acrylic compound having a molar ratio with acrylamide of 1: 9 to 5: 5 and a monomer mixture of the (meth) acrylamide. And a cross-linked poly (meth) acrylic acid (salt) obtained by polymerizing a (meth) acrylic monomer having a molar ratio of (meth) acrylic acid to (meth) acrylate of from 2: 8 to 10: 0. ) (B) in an amount of 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight. The crosslinked poly (meth) acrylic acid (salt) (B)
Is less than 0.1 part by weight, the resulting water-absorbing agent composition may have an insufficient water absorption capacity at high temperatures, or may corrode device materials during use. On the other hand, if it exceeds 50 parts by weight, the water absorption capacity of the resulting water-absorbing agent composition at a high temperature is reduced by polyvalent metal ions in the aqueous liquid.

The crosslinked polymer (A) used in the present invention comprises:
It is substantially insoluble in water and exerts a water stopping effect by swelling upon contact with an aqueous solution.

The crosslinked polymer (A) used in the present invention comprises:
The molar ratio of at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylate to (meth) acrylamide is 1: 9 to
It is necessary to be a crosslinked polymer obtained by polymerizing a monomer mixture having a ratio of 5: 5, preferably 2: 8 to 4: 6. The molar ratio is 5: 5 (excluding 5: 5) to 1
In the range of 0: 0, the water blocking effect of the crosslinked polymer (A) becomes insufficient due to the polyvalent metal salt in seawater. When the molar ratio is in the range of 1: 9 (excluding 1: 9) to 0:10,
Since the water absorbing ability and the gel consistency are reduced, stable water stopping ability cannot be obtained for a long period of time.

The (meth) acrylate used in the monomer mixture for synthesizing the crosslinked polymer (A) used in the present invention includes, for example, sodium (meth) acrylate and potassium (meth) acrylate. And metal salts such as calcium (meth) acrylate and magnesium (meth) acrylate, ammonium (meth) acrylate, and organic amine salts of (meth) acrylic acid. The mixing ratio of (meth) acrylic acid and (meth) acrylic acid salt is not particularly limited, but the molar ratio of (meth) acrylic acid and (meth) acrylic acid salt is considered in consideration of water absorption capacity, thermal stability, and the like. The ratio is 0:10 to 5: 5, preferably 0:10 to 2: 8.
It is. When the molar ratio is in the range of 5: 5 to 10: 0, the water absorption capacity may decrease at high temperatures.

The monomer mixture for synthesizing the crosslinked polymer (A) used in the present invention includes, for example, sulfonyl groups such as sulfoethyl (meth) acrylate and 2-acrylamido-2-methylpropanesulfonic acid. A water-absorbing agent which can be obtained from a monomer and its salt, (meth) acrylates such as methyl (meth) acrylate, ethyl (meth) acrylate and hydroxyethyl (meth) acrylate, and unsaturated monomers such as acrylonitrile; It can be added within a range that does not impair the water stopping effect of the composition.

The crosslinked polymer (A) used in the present invention comprises:
In order to have a well-balanced condition of water absorption such as water absorption rate, water absorption ratio to artificial seawater and gel consistency, it is necessary to reduce the water-containing gel-like polymer obtained by monomer polymerization or its dry and crushed product. It is preferable to add an agent for treatment. Examples of the reducing agent include sodium sulfite, potassium sulfite, potassium bisulfite, sodium thiosulfate, ammonium thiosulfate, potassium thiosulfate, ammonium sulfite, ammonium bisulfite, sodium bisulfite, L-ascorbic acid, ammonia, monoethanolamine, Glucose and the like. Among them, a method of adding sodium sulfite, sodium hydrogen sulfite, and sodium thiosulfate is particularly preferable. The amount of the reducing agent to be added is preferably in the range of 0.0001 to 0.02, particularly preferably in the range of 0.001 to 0.01 in terms of molar ratio to all monomers.

The crosslinked polymer (A) used in the present invention comprises:
The water absorption rate, ie, the equilibrium water absorption magnification of 90 for artificial seawater.
% Is preferably 8 minutes or less, particularly preferably 5 minutes or less. If the water absorption rate is longer than 8 minutes, the initial water-stopping effect of the obtained water-absorbing agent composition is reduced.

The crosslinked polymer (A) used in the present invention comprises:
The water absorption capacity with respect to artificial seawater is 8 times or more of its own weight, preferably 12 to 50 times. When the water absorption ratio is less than 8 times its own weight, the initial water-stopping effect and the long-term water-stopping effect of the obtained water-absorbing agent composition may be reduced.

The gel consistency of the crosslinked polymer (A) used in the present invention is preferably from 0.6 × 10 ^{5 to} 2.5 × 10 ^5
5 dyne · s / cm ³ , particularly preferably 1.0 × 10
^{It is 5 to} 1.8 × 10 ⁵ dyne · s / cm ³ . When the gel consistency is less than 0.6 × 10 ⁵ dyne · s / cm ³ , the water stopping power against infiltration water is insufficient, and it becomes difficult to maintain a sufficient water stopping ability for a long period of time. If the gel consistency exceeds 2.5 × 10 ⁵ dyne · s / cm ³ , the gel swelled by the salt water loses its slipperiness, so that the gel moves to the gap created in the sheath and stops. It may not be able to be watered, and the water-stopping ability of the resulting water-absorbing agent composition may decrease.

The average particle size of the crosslinked polymer (A) used in the present invention is preferably from 5 to 250 μm, particularly preferably from 10 to 100 μm. When the average particle diameter exceeds 250 μm, the water-absorbing agent composition may not be able to enter fine gaps or the water absorption rate may decrease. When the average particle diameter is less than 5 μm, the obtained water-absorbing agent composition The water stopping effect may be reduced.

The (meth) acrylate used in the monomer mixture for synthesizing the crosslinked poly (meth) acrylic acid (salt) (B) of the present invention includes, for example, sodium (meth) acrylate, ( Potassium (meth) acrylate,
Examples thereof include metal salts such as calcium (meth) acrylate and magnesium (meth) acrylate, ammonium (meth) acrylate, and organic amine salts of (meth) acrylic acid. The molar ratio of (meth) acrylic acid to (meth) acrylate is 2: 8 to 10: 0, preferably 5: 5
-10 to 10: 0, particularly preferably 7: 3 to 10: 0.
When the molar ratio is in the range of 0:10 to 2: 8 (excluding 2: 8), the crosslinked poly (meth) acrylic acid (salt) (B)
Does not show the effect of addition.

The monomer mixture for synthesizing the crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention includes, for example, sulfoethyl (meth) acrylate, 2-acrylamido-2-methyl Sulfone group-containing monomers such as propanesulfonic acid and salts thereof, (meth)
Methyl acrylate, ethyl (meth) acrylate, (meth) acrylates such as hydroxyethyl (meth) acrylate, unsaturated monomers such as acrylonitrile,
The water-absorbing agent composition can be added within a range that does not impair the water-stopping effect.

The average particle size of the crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention is preferably 250
μm or less, particularly preferably 20 μm or less, more preferably 5 μm or less. If the average particle size exceeds 250 μm, the particles may not enter the fine gaps or the effect of adding the crosslinked poly (meth) acrylic acid (salt) (B) may not be sufficiently obtained. .

When the crosslinked polymer (A) or crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention is produced by polymerization of the above-mentioned monomers, polymerization is carried out in the presence of a crosslinking agent. Preferably, a crosslinking agent is used. By using a cross-linking agent, the cross-linking density of the cross-linked polymer (A) or cross-linked poly (meth) acrylic acid (salt) (B) can be easily controlled, and therefore, the water absorption rate of these cross-linked products and the water absorption of artificial seawater It becomes easy to balance the conditions required for water stoppage, such as magnification and gel consistency.

There is no particular limitation on the timing of addition of the crosslinking agent.
For example, a cross-linking agent is added when polymerizing at least one monomer of (meth) acrylic compound and (meth) acrylamide selected from the group consisting of (meth) acrylic acid and (meth) acrylate. Alternatively, after the monomer is polymerized to obtain a substantially water-soluble polymer, a treatment such as heating may be performed by adding a crosslinking agent.

Examples of the crosslinking agent that can be used in producing the crosslinked polymer (A) or the crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention include divinylbenzene and ethylene glycol. Di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (Meth) acrylate, pentaerythritol di (meth) acrylate, N, N-methylenebisacrylamide, triallyl isocyanurate, trimethylolpropane diallyl ether, etc. Compounds; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbit, sorbitan, glucose, mannitol, mannitan, Polyhydric alcohols such as sugar and glucose; ethylene glycol diglycidyl ether, glycerin diglycidyl ether,
Polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, trimethylolpropane triglycidyl ether, glycerin Examples thereof include polyepoxy compounds such as triglycidyl ether, and one or more of these can be used in combination. As a crosslinking agent,
Among them, ethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, N,
N-methylenebisacrylamide and polyethylene glycol diglycidyl ether are preferred.

When a polyhydric alcohol is used as a cross-linking agent, it is preferable to carry out a heat treatment after polymerization at 150 to 250 ° C., and for a polyepoxy compound at 50 to 250 ° C.

When the cross-linking agent is used, when the cross-linked polymer (A) is synthesized, the amount of the cross-linking agent is preferably in the range of 0.00005 to 0.05, more preferably 0.0001, in a molar ratio with respect to the monomer. The range of -0.005 is preferable. When the amount of the cross-linking agent used exceeds 0.05 in molar ratio, the water absorption capacity of the obtained cross-linked polymer (A) tends to decrease and the gel viscosity tends to be too large. Conversely, 0.00005
When the amount of the water-absorbing agent composition is too small, the resulting cross-linked polymer (A) becomes sticky and causes a problem in handleability, or the gel viscosity becomes too small, and the water-stopping ability of the obtained water-absorbing agent composition decreases. There is. Crosslinked poly (meth) acrylic acid (salt)
The amount of the crosslinking agent used when synthesizing (B) is 0.00001 to 0.10, particularly 0.0
The range of 001 to 0.01 is preferred.

The polymerization method for obtaining the crosslinked polymer (A) or crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention may be any conventionally known method, for example, radical polymerization. Examples thereof include a method using a catalyst and a method of irradiating radiation, electron beam or ultraviolet ray, and a method using a radical polymerization catalyst is generally used.

Examples of the radical polymerization catalyst include peroxides such as hydrogen peroxide, benzoyl peroxide and cumene hydroperoxide, azo compounds such as azobisisobutyronitrile, ammonium persulfate, sodium persulfate and potassium persulfate. And redox initiators obtained by combining these with radical reducing agents such as persulfates and reducing agents such as sodium bisulfite, L-ascorbic acid and ferrous salts.

Examples of the polymerization solvent include water, methanol, ethanol, acetone, dimethylformamide,
Dimethyl sulfoxide, hexane, cyclohexane and the like, and a mixture thereof can be used.

The temperature at the time of polymerization depends on the type of the catalyst used, but a relatively low temperature is preferred because the molecular weight of the crosslinked polymer becomes large. However, for the polymerization to be complete, 20
C. or more, more preferably 20 to 10 ° C.
It is in the range of 0 ° C.

The concentration of the monomer in the polymerization system is not particularly limited, but may be in the range of 20 to 80% by weight, preferably 30 to 50% by weight in consideration of easy control of the polymerization reaction and yield and economy. Is preferred.

Although various forms can be adopted as a polymerization form, a method of polymerizing a gel-like hydropolymer while subdividing it by the shear force of a suspension polymerization, a casting polymerization, a precipitation polymerization, or a double-arm kneader (Japanese Patent Application Laid-Open No. No. 57-34101) is preferred.

In the case where the crosslinked polymer (A) or the crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention is produced by polymerization according to the above-mentioned method, a foaming agent or an inorganic substance is required before the polymerization. May be added. These additions have the effect of improving the initial water stopping ability of the obtained water absorbing agent composition.

The crosslinked polymer (A) and the crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention are synthesized by the above polymerization method and the like, and then, if necessary, filtered and dried.
It is obtained by pulverization or the like to obtain a desired particle shape. When drying after polymerization, the drying temperature is 50.
To 180 ° C, preferably 100 to 170 ° C. Crosslinked poly (meth) acrylic acid (salt) used in the present invention
As (B), particularly, a crosslinked product of sodium polyacrylate (partially neutralized product) (Nippon Shokubai's Aquaric C)
A), cross-linked polyacrylic acid (Carbopol manufactured by BF Goodrich, Hibiswako manufactured by Wako Pure Chemical Industries, Ltd.)
Junron manufactured by Nippon Pure Chemical Co., Ltd.) is preferred.

By fixing the water-absorbing agent composition thus obtained to a substrate, a water-blocking material such as a water-blocking tape or a water-blocking yarn can be obtained. There are various methods for fixing the water-absorbing agent composition to the base material to form a water-stopping material. For example, the following method can be employed.

(1) A fixing mixture containing an organic polymer binder, inorganic or organic fine particles, a fibrous substance, a surfactant, a solvent, and the like, if necessary, is added to the water-absorbing agent composition. It is applied to one or both sides of a sheet-like, tape-like or yarn-like substrate such as a film, or the substrate is impregnated with a fixing mixture. Thereafter, when a solvent is used, drying is performed, and when a thermosetting binder or a heat sealing binder is used, heat treatment is performed.

(2) The above fixing mixture is sandwiched between two or more sheets or tape-like base materials such as nonwoven fabric, woven fabric, paper and film. Thereafter, when a solvent is used, drying is performed, and when a thermosetting binder or a heat sealing binder is used, heat treatment is performed.

(3) A water-absorbing agent composition is added to a base material such as rubber or plastic, kneaded, and processed with a roll or an extruder to form a sheet- or tape-shaped water-stopping material. When rubber is used, it may be vulcanized if necessary.

To produce the water-stopping material of the present invention, a binder is not necessarily required, and a mixture obtained by dispersing a water-absorbing agent composition in an organic solvent can be used as a nonwoven fabric, woven fabric, paper, film,
The water-absorbing agent composition can be fixed to the base material simply by impregnating the base material into a sheet, tape, or yarn made of synthetic fibers, natural fibers, or the like. At this time, the cross-linked poly (meth)
Acrylic acid (salt) (B) also has a function as a binder.

In order to prevent the water absorbing agent composition from falling off the substrate, an organic polymer binder can be used.
At this time, the amount of the organic polymer binder used is preferably 5 to 100 parts by weight of the water absorbing agent composition.
It is 300 parts by weight, more preferably 10 to 80 parts by weight. If the amount of the organic polymer-based binder exceeds 300 parts by weight, the water-absorbing speed of the water-stopping material may decrease, and the water-stopping ability may decrease. If the amount of the organic polymer binder used is less than 5 parts by weight, the adhesive force to the base material is reduced, so that the water absorbing agent composition may fall off during handling such as incorporation into a cable. .

Examples of the organic polymer binder include synthetic rubber, natural rubber, polyacrylate, polyalkylene oxide, polyurethane, hydrophilic polyurethane, polyester, polyamide, polyethylene, ethylene-vinyl acetate copolymer, and polyvinyl alcohol. ,
Examples include carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, crosslinked polyacrylic acid, and the like.

In producing the water-stopping material of the present invention, various additives can be added for the purpose of improving the water-stopping ability and the like. Additives are not particularly limited, for example, asbestos, pulp, synthetic fibers, fibrous substances such as natural fibers, silica, alumina, synthetic silicate, magnesium carbonate, magnesium silicate, magnesium hydroxide, aluminum hydroxide,
Examples thereof include inorganic or organic fine particles such as calcium hydroxide, calcium carbonate, bentonite, kaolinite, zeolite, titanium oxide, activated clay, borax, zinc borate, and carbon black. In particular, inorganic fine particles are also effective in improving the flame retardancy of the waterproof material.

The average particle diameter of the inorganic fine particles is preferably 200 μm or less, particularly preferably 50 μm or less.
If the average particle size exceeds 200 μm, the obtained water-stopping material may have a reduced water-stopping capability, or the obtained water-stopping material may be too thick, so that it may not be possible to enter a fine cable gap.

The amount of addition of the inorganic fine particles depends on the water absorbing agent composition 1
The amount is preferably 0.05 to 100 parts by weight, particularly preferably 1 to 50 parts by weight, based on 00 parts by weight. If the amount is less than 0.05 parts by weight, the substantial addition effect is not exhibited, and if it exceeds 100 parts by weight, the swelling ratio of the water-stopping material is reduced, and the water-stopping effect may be reduced.

The substrate used for the water-stopping material of the present invention is not particularly limited. For example, a nonwoven fabric made of acrylic, polycarbonate, cellulose, etc., such as polyolefin, polyester, polyamide, polyacrylonitrile, etc.
Examples include woven fabric, paper, film, and yarn. Among them, a long-fiber non-woven fabric sheet made of polyester, acrylic or the like manufactured by a spun bond method is preferable in view of strength, water stopping performance, and non-biodegradability.

The weight of the water-absorbing agent composition fixed to the water-stopping material of the present invention is not particularly limited.
The dry weight is preferably from 5 to 300 g / m ² , particularly preferably from 30 to 150 g / m ² . If the adhesion amount is less than 5 g / m ^{2, the} water-stopping effect of the obtained water-stopping tape may be low. On the other hand, if the amount exceeds 300 g / m ² , the flexibility of the obtained water-stopping tape becomes poor, so that the workability may be deteriorated. In the case of a waterproof yarn, the dry weight is preferably 0.05 to 30 g / m, particularly preferably 0.1 to 5 g / m. When the adhesion amount is less than 0.05 g / m, the water stopping effect of the obtained water stopping yarn may be low. On the other hand, if the adhesion amount exceeds 30 g / m, the workability may be deteriorated because the flexibility of the obtained waterproof yarn becomes poor.

[0046]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited only to these Examples.

The water absorption capacity, water absorption rate, gel consistency, heat resistance, p of the obtained water absorbing agent composition or crosslinked polymer (A)
H and the water stopping performance of the water stopping material were measured by the following method.

(1) Method of Measuring Water Absorption Ratio A 0.2 g sample of the water absorbing agent composition or the crosslinked polymer (A) was placed in a non-woven tea bag type bag (40 mm × 150 mm).
, And immersed in artificial seawater having a salt concentration shown in Table 1. One hour after immersion, the tea bag-type bag was pulled up, drained for 10 seconds, weighed, and the water absorption capacity was calculated by the following equation (1).

[0049]

[Table 1]

[0050]

(Equation 1)

(2) Method of Measuring Water Absorption Rate The water absorption rate is measured using the measuring device shown in FIG.
First, a depth of 40 mm and a low area of 50.2 cm in FIG.
^The nonwoven fabric 2 was spread on the bottom of the cylindrical container 1 of No. 2, and 0.5 g of the sample 3 of the water-absorbing agent composition or the crosslinked polymer (A) was evenly dispersed, and the nonwoven fabric 4 was placed thereon. Then, add 9
A perforated lid 5 weighing 1.6 g was placed, and a distance sensor 6 was installed on the top. 50 g of artificial seawater having a salt concentration shown in Table 1 was added to the container 1 to allow the sample 3 to absorb water and swell,
The height at which the distance that the swollen sample 3 pushed up the perforated lid 5 reached the maximum value was measured. The time at which the height reached 90% of the height when the maximum value was reached was defined as the water absorption rate.

(3) Method for Measuring Gel Viscosity A 2.5% sample of the water-absorbing agent composition or the crosslinked polymer (A) was mixed with 35 g of a 3.5% aqueous NaCl solution to prepare a water-absorbing gel. The water-absorbing gel was placed in a container having a depth of 6 cm and a bottom area of 9 cm ² , and the viscosity of the gel was measured with a neocard meter manufactured by Iio Electric Co., Ltd. Here, the gel consistency refers to an apparent viscosity acting in the form of a frictional force against flowing the gel.

(4) Heat Resistance Evaluation Method The water-absorbing agent composition or the crosslinked polymer (A) was heated at 160 ° C. for 4 days, and the rate of decrease in the water absorption capacity at that time was calculated by the following formula (2). The heat resistance was evaluated.

[0054]

(Equation 2)

(5) Method of measuring pH 0.5 g of sodium chloride was dissolved in 200 ml of deionized water, and 0.5 g of a sample of the water-absorbing agent composition or the crosslinked polymer (A) was dispersed therein and measured with a pH meter. .

(6) Method of Evaluating Water-Stopping Ability of Water-Stopping Material A water-stopping tape as a water-stopping material is wrapped around a glass rod having an outer diameter of 13.5 mm and a length of 2000 mm, and the glass rod is placed in a glass tube having an inner diameter of 15 m. A simulated cable for measuring the water-stopping ability of the water-stopping material was prepared.

The simulated cable was held horizontally, and a container filled with artificial seawater having a salt concentration shown in Table 1 was connected to one end of the simulated cable by a rubber tube, and the liquid level in the container was changed from the simulated cable. It was kept at a height of 1000 mm. Next, the cock at the bottom of the container was opened to guide the artificial seawater to the simulated cable, and it was observed that the artificial seawater entered the simulated cable.
The distance from the end of the simulated cable to the tip into which artificial seawater had penetrated was measured 1 hour and 14 days after the introduction of the artificial seawater to evaluate the water stopping ability of the water stopping tape.

Comparative Example 1 In a 500 ml cylindrical separable flask, 31.3 g (0.33 mol) of sodium acrylate, 55.2 g (0.78 mol) of acrylamide, and 0.20 g (0%) of N, N-methylenebisacrylamide .0013 mol) and 165 g of water were charged and uniformly dissolved. After the atmosphere in the flask was replaced with nitrogen, the flask was heated to 25 ° C. on a hot water bath, and 1.94 g of a 20% aqueous solution of sodium persulfate and 1.94 g of a 2% aqueous solution of L-ascorbic acid were added. . The obtained polymer was finely divided, and after adding 2.1 g of 35% sodium bisulfite, the polymer was dried at 160 ° C. for 3 hours and pulverized to obtain crosslinked polymer particles having an average particle diameter of 46 μm (A
-1) was obtained. The physical properties of the obtained crosslinked polymer particles (A-1) were measured by the methods described above, and the results are shown in Table 2.

Example 1 To 100 parts by weight of the crosslinked polymer particles (A-1) obtained in Comparative Example 1, 2 parts by weight of a crosslinked polyacrylic acid (Hibiswako 104, manufactured by Wako Pure Chemical Industries, Ltd.) was added. Thus, a water absorbing agent composition (1) of the present invention was obtained. Table 2 shows the physical property measurement results of the water absorbing agent composition (1).

Comparative Example 2 In place of 31.3 g of sodium acrylate, 55.2 g of acrylamide, 0.20 g of N, N-methylenebisacrylamide and 165 g of water used in Comparative Example 1, 23.5 g of sodium acrylate (0.25 g) was used. Mol), 5.76 g (0.08 mol) of acrylic acid, 55.
2 g (0.78 mol), N, N-methylenebisacrylamide 0.23 g (0.0015 mol) and water 165
Except for using g, the procedure of Example 1 was repeated to obtain crosslinked polymer particles (A-2) having an average particle diameter of 43 µm. The physical properties of the obtained crosslinked polymer particles (A-2) were measured by the methods described above, and the results are shown in Table 2.

Example 2 100 parts by weight of the crosslinked polymer particles (A-1) obtained in Comparative Example 1 were added to a crosslinked polymer of acrylic acid-sodium acrylate (acrylic acid: sodium acrylate = 80: 20,
20 parts by weight (average particle size: 15 μm) were added to obtain a water absorbing agent composition (2) of the present invention. Table 2 shows the measurement results of physical properties of the water absorbing agent composition (2).

[0062]

[Table 2]

Examples 3 to 4 A polymer having an average molecular weight of 60,000 obtained by polymerizing a monomer mixture comprising 35% by weight of methyl methacrylate, 40% by weight of butyl acrylate, 15% by weight of acrylic acid and 10% by weight of hydroxyethyl methacrylate. 20 parts by weight of an acrylate ester, 100 parts by weight of the water absorbing agent composition (1) or (2) obtained in Examples 1 and 2, 50 parts by weight of white carbon as inorganic fine particles, and nonylphenol ethoxylate (Asahi 0.5 parts by weight of Adecitol NP-650 manufactured by Denka Kogyo Co., Ltd.) and 40 parts by weight of isopropyl alcohol were mixed to prepare a fixing composition.

This fixing composition was applied to both sides of a polyester film having a thickness of 50 μm and dried to obtain water-stopping tapes (1) and (2) as the water-stopping material of the present invention. The thickness of the water-stop tape was about 140 μm, and the amount of the water-absorbing agent composition attached was about 60 g / m ² . The water stopping performance of the obtained water stopping tape was evaluated by the method described above, and the results are shown in Table 3.

Comparative Example 3 31.3 g (0.33 mol) of sodium acrylate and acrylic acid 1 were placed in a 500-ml cylindrical separable flask.
0.3 g (0.11 mol), 47.3 g of acrylamide
(0.67 mol) and 350 g of water were charged and uniformly dissolved. After the atmosphere in the flask was replaced with nitrogen, the temperature was 25 ° C on a hot water bath.
4 g of a 20% aqueous sodium persulfate solution and 2 g
4 g of a% L-ascorbic acid aqueous solution was added, and stirring was stopped to carry out polymerization. 400 g of water and 0.90 g of ethylene glycol diglycidyl ether were added to the obtained polymer.
(0.0052 mol) was added to obtain an aqueous solution for fixing. A polyester long fiber spunbond nonwoven fabric sheet (ELTAS E5030 manufactured by Asahi Kasei Kogyo Co., Ltd.) is added to this aqueous solution for fixing.
, And then pulled up, heated and dried at a temperature of 120 ° C. Further, the impregnation and the heating and drying were repeated to obtain a sheet to which the water absorbing agent composition was adhered. The thickness of this sheet was 50 μm, and the amount of the water-absorbing agent composition formed by heating and drying the fixing aqueous solution was 20 g / m ² .
Three sheets were stacked to obtain a comparative water-stop tape (1).
The water-stopping ability of the obtained comparative water-stop tape (1) was evaluated by the above method, and the results are shown in Table 3.

[0066]

[Table 3]

[0067]

The water-absorbing agent composition of the present invention and the water-stopping material supporting the water-absorbing agent composition include seawater, groundwater, blood,
Exhibits an excellent water-stopping effect even for aqueous liquids containing salts such as urine and cement water, has a neutral pH range, and does not decrease the water absorption capacity even at high temperatures and has excellent heat resistance. . Therefore, the water stopping effect is maintained for a long period of time and other materials are not damaged, so the holding tape for optical cable, the water absorbing tape for optical cable, the water stopping tape for power cable, the water stopping tape for communication cable Suitable for tape, waterproof tape for concrete, seal tape for civil engineering, seal tape for agricultural and horticultural use, seal tape for medical use, etc.

[Brief description of the drawings]

FIG. 1 is a partially broken explanatory view showing an apparatus for measuring a water absorption rate of a water absorbing agent composition or a crosslinked polymer (A) in the present invention.

[Explanation of symbols]

 1. . . Container 2. . . Non-woven fabric 3. . . 3. Sample of water-absorbing agent composition or crosslinked polymer (A) . . Non-woven fabric 5. . . Perforated lid 6. . . Distance sensor

 ────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-58-125748 (JP, A) JP-A-61-263639 (JP, A) Table of Japanese Patent Publication No. 61-500150 (JP, A)

Claims (6)

(57) [Claims] 1. The molar ratio of at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylate to (meth) acrylamide is 1: 9 to 5: 5. (Meth) acrylic acid and (meth) acrylic acid with respect to 100 parts by weight of a crosslinked polymer (A) obtained by polymerizing a monomer mixture comprising the (meth) acrylic compound and the (meth) acrylamide Crosslinked poly (meth) acrylic acid (salt) obtained by polymerizing a (meth) acrylic monomer having a molar ratio with a salt of 2: 8 to 10: 0
A water-absorbing composition comprising (B) in an amount of 0.1 to 50 parts by weight. 2. (Meth) in the crosslinked polymer (A)
The molar ratio of acrylic acid and (meth) acrylate is 5: 5
The composition according to claim 1, wherein the ratio is ０0:10. 3. The crosslinked polymer (A) has a water absorption rate of not more than 8 minutes represented by a time required to reach 90% of an equilibrium water absorption capacity with respect to artificial seawater, and has a water absorption capacity with respect to artificial seawater of at least 8 times its own weight. And the gel consistency is 0.6 × 1
0 ⁵ ~2.5 × 10 ⁵ A composition according to claim 1 which is dyne · s / cm ^3. 4. The crosslinked poly (meth) acrylic acid (salt)
The composition according to claim 1, wherein the molar ratio of (meth) acrylic acid to (meth) acrylate in (B) is from 7: 3 to 10: 0. 5. A composite water-stopping material comprising the water-absorbing agent composition supported on a substrate. 6. The composite waterproof material according to claim 5, wherein the base material is a tape.