JPH0570762A - Water absorbent composition and water stop material comprising the same - Google Patents

Abstract

PURPOSE:To provide a water absorbent composition and a water stop material which are excellent in initial and long-term water stop capacity even when salt water is penetrated into the sheath of a cable and also in heat stability. CONSTITUTION:A water absorbent composition comprising 100 pts.wt. crosslinked polymer obtained by polymerizing a monomer mixture containing at least one (meth)acrylic compound selected from the group consisting of (meth) acrylic acid and a (meth)acrylate and (meth)acrylamide in a molar ratio of 1:9-5:5 and 0.1-50 pts.wt. crosslinked poly(meth)acrylic acid (salt) obtained by polymerizing a (meth)acrylic monomer mixture containing (meth)acrylic acid and (meth)acrylate in a molar ratio of 2:8-10:0; and a water stop material prepared by impregnating a support with the composition. The water stop material can exhibit excellent water stop effect for an aqueous liquid containing salts, does not decrease in its water absorption ratio at high temperatures, and is excellent in heat resistance.

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 which is mainly used as a water-stopping agent and a water-stopping material comprising a base material carrying the water-absorbing agent composition. More specifically, the present invention provides
When water, especially high-concentration salt water such as seawater, enters the sheath of cables such as optical cables and metal cables such as communication cables and power cables, salt water moves inside the sheath and deteriorates cables and various devices. The present invention relates to a water-absorbing agent composition used as a water-stopping agent and the like for preventing such a phenomenon, and a water-stopping material obtained by supporting the water-absorbing agent composition on a substrate.

[0002]

2. Description of the Related Art When a sheath of a cable is damaged and water enters the sheath, the water quickly moves inside the sheath and deteriorates a communication cable such as an optical fiber, a power line or various devices. .. Then, in order to solve this problem, a method of inserting a substantially water-insoluble and water-swellable water-absorbing agent into the sheath has been proposed.

As such water-absorbing agents, conventionally, sodium polyacrylate crosslinked products, neutralized products of starch-acrylic acid graft copolymers, saponified products of vinyl acetate-acrylic acid ester copolymers, isobutylene-maleic anhydride. A water-absorbing resin such as a neutralized product of a cross-linked acid copolymer fixed to a non-woven fabric is used (Japanese Patent Laid-Open No. 64-76609).
No., No. 61-129228, Shokai Kai). However, the above water-absorbing agent has a slow water-absorption rate, does not have sufficient water-absorption capacity in salt water, or has an improper gel consistency of the water-absorbing resin used, so that the ground, seabed, etc. There is a problem that water cannot be prevented from entering when the cable is buried in the.

Further, a water-absorbent tape excellent in waterproofness against seawater is produced by impregnating a base material such as a non-woven fabric with a water-soluble polymer such as sulfoalkyl (meth) acrylate or acrylamide and a cross-linking agent and then heat-crosslinking. It has been proposed (Japanese Patent Laid-Open No. 2-1690). But,
The water-blocking tape in which the base material and the water-absorbent resin are strongly integrated has a problem that only a water-blocking tape having a low water-blocking ability can be obtained because of its low water-absorbing speed.

In order to solve these problems, the inventors of the present invention have proposed a specific polymer cross-linked product composed of a specific (meth) acrylamide and a (meth) acrylic acid salt (Japanese Patent Application No. Hei 10 (1999) -135242). 2-245424). However, since the cross-linked polymer has a high pH, there is a problem that the aqueous liquid that comes into contact with the solution becomes alkaline and corrodes the apparatus material during use. On the other hand, by copolymerizing this crosslinked polymer with (meth) acrylic acid, the pH can be lowered, but there is a problem of heat resistance that the water absorption capacity at high temperature is reduced.

[0006]

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

[0007]

[Means for Solving the Problems] These objects are to provide at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylic acid salt and (meth) acrylamide. The molar ratio is 1: 9 to 5: 5
(Meth) acrylic acid and (meth) acrylic acid based on 100 parts by weight of a cross-linked polymer (A) obtained by polymerizing a monomer mixture consisting of the (meth) acrylic compound and the (meth) acrylamide. The molar ratio with salt is 2: 8 to 1
The crosslinked poly (meth) acrylic acid (salt) (B) obtained by polymerizing 0: 0 (meth) acrylic monomer is
It is achieved by a water-absorbing agent composition blended in the range of 50 parts by weight and a water-stopping material having the substrate carrying the water-absorbing agent composition.

[0008]

The water absorbing agent composition according to the present invention comprises at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylic acid salt, and (meth).
Based on 100 parts by weight of a cross-linked polymer (A) obtained by polymerizing a monomer mixture consisting of the (meth) acrylic compound and the (meth) acrylamide having a molar ratio with acrylamide of 1: 9 to 5: 5. Crosslinked poly (meth) acrylic acid (salt obtained by polymerizing a (meth) acrylic monomer having a molar ratio of (meth) acrylic acid and (meth) acrylic acid salt of 2: 8 to 10: 0. ) (B) is blended in the range of 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight. The crosslinked poly (meth) acrylic acid (salt) (B)
If less than 0.1 part by weight, the water absorption capacity of the resulting water absorbing agent composition at high temperature may be insufficient, or the material of the device may be corroded during use. On the other hand, when it exceeds 50 parts by weight, the water absorption capacity of the resulting water absorbing agent composition at high temperature is lowered by the polyvalent metal ion in the aqueous liquid.

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

The crosslinked polymer (A) used in the present invention is
The molar ratio of at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylic acid salt to (meth) acrylamide is 1: 9 to.
It is necessary to be a cross-linked 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 absorption capacity and gel consistency decrease, stable water stopping performance cannot be obtained for a long period of time.

Examples of the (meth) acrylate used in the monomer mixture for synthesizing the crosslinked polymer (A) used in the present invention include sodium (meth) acrylate and potassium (meth) acrylate. , Metal salts of calcium (meth) acrylate, magnesium (meth) acrylate, ammonium (meth) acrylate, organic amine salts of (meth) acrylic acid, and the like. 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.
Is. When the molar ratio is in the range of 5: 5 to 10: 0, the water absorption capacity may decrease at high temperatures.

In addition, the monomer mixture for synthesizing the crosslinked polymer (A) used in the present invention includes, for example, a sulfo group such as sulfoethyl (meth) acrylate and 2-acrylamido-2-methylpropanesulfonic acid. A water-absorbing agent which can be obtained from a contained monomer and its salt, (meth) acrylic acid ester such as methyl (meth) acrylate, ethyl (meth) acrylate, hydroxyethyl (meth) acrylate, and unsaturated monomer such as acrylonitrile. It can be added within a range that does not impair the water blocking effect of the composition.

The crosslinked polymer (A) used in the present invention comprises
In order to have well-balanced conditions for water stopping such as water absorption rate, water absorption capacity against artificial seawater, and gel consistency, a water-containing gel polymer obtained by polymerization of monomers or its dried pulverized product is reduced. It is preferable to add an agent for treatment. Examples of the reducing agent include sodium sulfite, potassium sulfite, potassium hydrogen sulfite, sodium thiosulfate, ammonium thiosulfate, potassium thiosulfate, ammonium sulfite, ammonium hydrogen sulfite, sodium hydrogen sulfite, L-ascorbic acid, ammonia, monoethanolamine, Glucose and the like can be mentioned. Among them, the method of adding sodium sulfite, sodium hydrogen sulfite, or sodium thiosulfate is particularly preferable. The reducing agent is added in a molar ratio of 0.0001 to 0.02, preferably 0.001 to 0.01, based on the total amount of the monomers.

The crosslinked polymer (A) used in the present invention is
Absorption rate, that is, the equilibrium absorption capacity for artificial seawater of 90
The time to reach% is preferably 8 minutes or less, particularly preferably 5 minutes or less. If the water absorption rate is longer than 8 minutes and takes a long time, the initial water-stopping effect of the obtained water absorbing agent composition is lowered.

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

The gel consistency of the crosslinked polymer (A) used in the present invention is preferably 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 infiltrated water is insufficient, and it becomes difficult to maintain a sufficient water stopping ability for a long period of time. When the gel consistency exceeds 2.5 × 10 ⁵ dyne · s / cm ³ , the slidability of the gel swollen with salt water is lost, and as a result, the gel moves to the gap formed in the sheath and stops. It may not be possible to make it water, and the water-stopping ability of the resulting water-absorbent composition may decrease.

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

Examples of the (meth) acrylate used in the monomer mixture for synthesizing the crosslinked poly (meth) acrylic acid (salt) (B) of the present invention include sodium (meth) acrylate and ( (Meth) potassium 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) acrylic acid salt is 2: 8 to 10: 0, preferably 5: 5.
It is: 10 to 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) is used.
The effect of addition of does not appear.

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

The average particle size of the crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention is preferably 250.
It is not more than μm, particularly preferably not more than 20 μm, more preferably not more than 5 μm. If the average particle size exceeds 250 μm, it may not be possible to 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 polymerizing the above-mentioned monomers, the polymerization is carried out in the presence of a crosslinking agent. It is preferable to use a crosslinking agent. By using a cross-linking agent, the cross-linking density of the cross-linked polymer (A) and 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 absorption of water into artificial seawater. It becomes easy to balance the conditions necessary for water stoppage such as the magnification and the gel consistency.

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

Examples of the cross-linking agent that can be used in the production of the cross-linked polymer (A) and cross-linked 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. have two or more ethylenically unsaturated groups in one molecule. Compounds; ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, polyglycerin, propylene glycol, diethanolamine, triethanolamine, polypropylene glycol, polyvinyl alcohol, pentaerythritol, sorbit, sorbitan, glucose, mannitol, mannitane, syrup 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 these can be used alone or in combination of two or more. As a cross-linking 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 the cross-linking agent, it is preferable to carry out heat treatment after polymerization at 150 to 250 ° C., and in the case of a polyepoxy compound, at 50 to 250 ° C.

When the cross-linked polymer (A) is synthesized, the amount of the cross-linking agent used is preferably in the range of 0.00005 to 0.05, particularly 0.0001 in terms of molar ratio with respect to the monomer. The range of 0.005 is preferable. When the amount of the cross-linking agent used is more than 0.05 in terms of molar ratio, the water absorption capacity of the resulting cross-linked polymer (A) tends to decrease, and the gel consistency tends to increase too much. On the contrary, 0.00005
When the amount is less than the following, when the obtained crosslinked polymer (A) becomes sticky and has a problem in handleability, or the gel viscosity becomes too small, the water-stopping ability of the resulting water-absorbing agent composition decreases. There is. Cross-linked poly (meth) acrylic acid (salt)
The amount of the cross-linking agent used when synthesizing (B) is 0.00001 to 0.10, especially 0.0
The range of 001-0.01 is preferable.

The polymerization method for obtaining the crosslinked polymer (A) and the 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 with radiation, electron beam or ultraviolet ray, and a method using a radical polymerization catalyst is usually 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. A redox-based initiator obtained by combining a radical generator such as persulfate and the like and a reducing agent such as sodium bisulfite, L-ascorbic acid, and ferrous salt is used.

Examples of the polymerization solvent include water, methanol, ethanol, acetone, dimethylformamide,
It is possible to use dimethyl sulfoxide, hexane, cyclohexane, etc., or a mixture thereof.

The temperature at the time of polymerization varies depending on the kind of the catalyst used, but a relatively low temperature is preferable because the molecular weight of the crosslinked polymer becomes large. However, it takes 20 to complete the polymerization.
It is preferably at least ℃, more preferably 20 to 10
It is in the range of 0 ° C.

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

Although various forms can be adopted as the polymerization form, suspension polymerization, casting polymerization, precipitation polymerization, and a method of polymerizing while subdividing the gel-like water-containing polymer by the shearing force of a double-arm kneader (Japanese Patent Application Laid-open No. Sho-62-1994). 57-34101) is preferred.

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

The crosslinked polymer (A) and crosslinked poly (meth) acrylic acid (salt) (B) used in the present invention are synthesized by the above-mentioned polymerization method and the like, and if necessary, filtered and dried,
It can be obtained by pulverizing into fine particles to obtain a desired particle shape. When drying after the polymerization, the drying temperature is 50.
~ 180 ° C, preferably 100-170 ° C. Crosslinked poly (meth) acrylic acid (salt) used in the present invention
As (B), in particular, sodium polyacrylate (partially neutralized product) cross-linked product (Aqualic C manufactured by Nippon Shokubai Co., Ltd.)
A), crosslinked polyacrylic acid (Carbopol manufactured by BF Goodrich, Hibiswako manufactured by Wako Pure Chemical Industries, Ltd.,
Junron manufactured by Nippon Pure Chemical Co., Ltd.) is preferable.

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

(1) If necessary, an organic polymer binder, inorganic or organic fine particles, a fibrous substance, a surfactant, a solvent and the like are added to the water-absorbing agent composition to prepare a fixing mixture, which is then applied to a non-woven fabric, woven fabric or paper. , A sheet-like film such as a film, a tape-like or a yarn-like substrate is coated on one side or both sides, or the substrate is impregnated with the fixing mixture. Then, when a solvent is used, it is dried, and when a thermosetting binder or a heat-sealable binder is used, heat treatment is performed.

(2) The above fixing mixture is sandwiched between two or more sheet-like or tape-like substrates such as non-woven fabrics, woven fabrics, papers and films. Then, when a solvent is used, it is dried, and when a thermosetting binder or a heat-sealable binder is used, heat treatment is performed.

(3) A water-absorbent composition is added to a base material such as rubber or plastic and kneaded, and processed by a roll, an extruder or the like to obtain a sheet-shaped or tape-shaped waterproof material. When rubber is used, it may be vulcanized if necessary.

In order to produce the water blocking material of the present invention, a binder is not always necessary, and a mixture obtained by dispersing the water absorbing composition in an organic solvent is used as a nonwoven fabric, woven fabric, paper, film,
The water-absorbent composition can be fixed to the substrate by merely impregnating the sheet-shaped, tape-shaped or yarn-shaped substrate made of synthetic fiber or natural fiber. At this time, cross-linked poly (meth)
The acrylic acid (salt) (B) also has a function as a binder.

In order to prevent the water absorbing agent composition from falling off the base material, 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.
The amount is 300 parts by weight, more preferably 10 to 80 parts by weight. If the amount of the organic polymer-based binder used exceeds 300 parts by weight, the water-absorption rate of the water-blocking material may decrease and the water-blocking ability may decrease. When the amount of the organic polymer-based binder used is less than 5 parts by weight, the adhesive strength to the base material is lowered, 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, polyacrylic acid ester, polyalkylene oxide, polyurethane, hydrophilic polyurethane, polyester, polyamide, polyethylene, ethylene-vinyl acetate copolymer, polyvinyl alcohol. ,
Examples thereof include carboxymethyl cellulose, hydroxyethyl cellulose, polyacrylic acid, and polyacrylic acid crosslinked products.

In producing the water blocking material of the present invention, various additives can be added for the purpose of improving the water blocking ability. The additive is not particularly limited, for example, asbestos, pulp, synthetic fibers, fibrous substances such as natural fibers, silica, alumina, synthetic silicates, 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, the inorganic fine particles are effective in improving the flame retardancy of the waterproof material.

The average particle size 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 water blocking ability of the obtained water blocking material may be reduced, or the obtained water blocking material may become thick, so that it may not be able to enter the fine cable gap.

The amount of the inorganic fine particles added depends on the water absorbing 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 it is less than 0.05 parts by weight, the substantial addition effect will not be exhibited, and if it exceeds 100 parts by weight, the swelling ratio of the water blocking material may be low and the water blocking effect may be lowered.

The base material used for the water blocking material of the present invention is not particularly limited, but for example, a non-woven fabric made of acrylic such as polyolefin, polyester, polyamide, polyacrylonitrile, polycarbonate, cellulose, or the like,
Woven cloth, paper, film, yarn and the like can be mentioned. Among them, long-fiber non-woven fabric sheets such as polyester and acrylic produced by the spunbond method are preferable in terms of strength, water-stopping performance and non-biodegradability.

The weight of the water-absorbent composition adhered to the water-stopping material of the present invention is not particularly limited, but in the case of the water-stopping tape,
The dry weight is preferably 5 to 300 g / m ² , and particularly preferably 30 to 150 g / m ² . When the adhesion amount is less than 5 g / m ^{2, the} water blocking effect of the obtained water blocking tape may be low. On the other hand, if the amount of adhesion exceeds 300 g / m ² , the flexibility of the resulting water-blocking tape becomes poor, and the workability may deteriorate. In the case of the waterproof yarn, the dry weight is preferably 0.05 to 30 g / m, particularly preferably 0.1 to 5 g / m. If the adhesion amount is less than 0.05 g / m, the water blocking effect of the water blocking yarn obtained may be low. Further, when the adhesion amount exceeds 30 g / m, workability may be deteriorated due to poor flexibility of the water blocking yarn obtained.

[0046]

The present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to these examples.

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

(1) Method for measuring water absorption ratio 0.2 g of a sample of the water absorbent composition or the crosslinked polymer (A) was used as a tea bag type bag (40 mm × 150 mm) made of a non-woven fabric.
And then immersed in artificial seawater having the salt concentration shown in Table 1. After one hour from the immersion, the tea bag type bag was pulled up, drained for 10 seconds, then weighed, and the water absorption capacity was calculated by the following formula (1).

[0049]

[Table 1]

[0050]

[Equation 1]

(2) Water absorption rate measuring method The water absorption rate is measured using the measuring apparatus shown in FIG.
First, the depth in FIG. 1 is 40 mm and the low area is 50.2 cm.
² the bottom of the cylindrical container 1 laid nonwoven fabric 2, carrying the nonwoven fabric 4 over the water-absorbent agent composition or crosslinked polymer sample 3 (A) and 0.5g uniformly scattered. Then 9 on this
A perforated lid 5 weighing 1.6 g was placed on top of which a distance sensor 6 was installed. 50 g of artificial seawater having the salt concentration shown in Table 1 was added to the container 1 to absorb and swell the sample 3 described above,
The height when the swollen sample 3 pushed up the perforated lid 5 and reached the maximum distance was measured. The time taken for the height to reach 90% of the height when the maximum value was reached was defined as the water absorption rate.

(3) Method for measuring gel viscosity A water absorbing gel was prepared by mixing 2.5 g of a sample of the water absorbent composition or the crosslinked polymer (A) with 35 g of a 3.5% NaCl aqueous solution. The water-absorbent gel was placed in a container having a depth of 6 cm and a bottom area of 9 cm ² , and the consistency of the gel was measured by a neocard meter manufactured by Iio Denki Co., Ltd. Here, the gel consistency means an apparent viscosity that works in the form of frictional force for causing the gel to flow.

(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 water absorption capacity at that time was calculated by the following formula (2). The heat resistance was evaluated.

[0054]

[Equation 2]

(5) Method for 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 inside a glass tube having an inner diameter of 15 m. Then, a simulated cable for measuring the water-stopping ability of the water-stopping material was prepared by inserting the cable into the slab so that the gaps would be uniform.

This simulated cable was held horizontally, and a container filled with artificial seawater with salt concentration shown in Table 1 was connected to one end of the simulated cable with 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 water-stopping ability of the water-stop tape was evaluated by measuring the distance from the end of the simulated cable to the tip into which the artificial seawater penetrated, 1 hour and 14 days after the introduction of the artificial seawater.

Comparative Example 1 Sodium acrylate 31.3 g (0.33 mol), acrylamide 55.2 g (0.78 mol), N, N-methylenebisacrylamide 0.20 g (0) were placed in a 500 ml cylindrical separable flask. (.0013 mol) and 165 g of water were charged and uniformly dissolved. After replacing the inside of the flask with nitrogen, the flask was heated to 25 ° C. in a water bath, 1.94 g of 20% sodium persulfate aqueous solution and 1.94 g of 2% L-ascorbic acid aqueous solution were added, and stirring was stopped to polymerize. .. The obtained polymer was subdivided, and after adding 2.1 g of 35% sodium hydrogen sulfite, it was dried at 160 ° C. for 3 hours and pulverized to obtain crosslinked polymer particles (A having an average particle diameter of 46 μm).
-1) was obtained. The physical properties of the resulting 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 polyacrylic acid crosslinked product (Hibiswako 104, manufactured by Wako Pure Chemical Industries, Ltd.) was added. Thus, the water absorbing agent composition (1) of the present invention was obtained. Table 2 shows the results of measuring the physical properties of the water absorbent composition (1).

Comparative Example 2 Instead of 31.3 g of sodium acrylate used in Comparative Example 1, 55.2 g of acrylamide, 0.20 g of N, N-methylenebisacrylamide and 165 g of water, 23.5 g (0.25) of sodium acrylate was used. ), Acrylic acid 5.76 g (0.08 mol), acrylamide 55.
2 g (0.78 mol), N, N-methylenebisacrylamide 0.23 g (0.0015 mol) and water 165
The procedure of Example 1 was repeated except that g was used to obtain crosslinked polymer particles (A-2) having an average particle diameter of 43 μm. The physical properties of the resulting 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 was added to a crosslinked polymer of acrylic acid-sodium acrylate (acrylic acid: sodium acrylate = 80: 20,
20 parts by weight of an average particle diameter of 15 μm) was added to obtain a water absorbent composition (2) of the present invention. Table 2 shows the results of measuring the physical properties of the water absorbent composition (2).

[0062]

[Table 2]

Examples 3 to 4 Polyimide having an average molecular weight of 60,000 obtained by polymerizing a monomer mixture consisting of 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 acrylic acid ester, 100 parts by weight of the water absorbent composition (1) or (2) obtained in Examples 1 and 2, 50 parts by weight of white carbon as inorganic fine particles, nonylphenol ethoxylate (Asahi A fixing composition was prepared by mixing 0.5 parts by weight of ADEKA TOL NP-650 manufactured by Denka Kogyo Co., Ltd. and 40 parts by weight of isopropyl alcohol.

This fixing composition was applied on both sides of a polyester film having a thickness of 50 μm and dried to obtain water-stop tapes (1) and (2) which are water-stop materials of the present invention. The thickness of this water blocking tape was about 140 μm, and the amount of the water absorbing composition deposited was about 60 g / m ² . The water blocking ability of the obtained water blocking tape was evaluated by the above method, and the results are shown in Table 3.

Comparative Example 3 31.3 g (0.33 mol) of sodium acrylate and 1 part of acrylic acid were placed in a 500 ml cylindrical separable flask.
0.3 g (0.11 mol), acrylamide 47.3 g
(0.67 mol) and 350 g of water were charged and uniformly dissolved. After replacing the inside of the flask with nitrogen, 25 ° C on a hot water bath
Heat to 4 g of 20% aqueous sodium persulfate solution and 2
% L-ascorbic acid aqueous solution (4 g) was added, stirring was stopped, and polymerization was performed. 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 a fixing aqueous solution. Polyester long-fiber spunbonded non-woven fabric sheet (ELTAS E5030 manufactured by Asahi Kasei Corporation) was added to this fixing aqueous solution.
Was impregnated, then pulled up, heated at 120 ° C. and dried. Further, this impregnation and heat drying were repeated to obtain a sheet to which the water absorbing agent composition was attached. The thickness of this sheet was 50 μm, and the amount of the water absorbing agent composition produced by heating and drying the fixing aqueous solution was 20 g / m ² .
Three sheets of this sheet were stacked to form a comparative waterproof tape (1).
The water blocking ability of the obtained comparative water blocking 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 blocking material carrying the water absorbing agent composition are seawater, groundwater, blood,
It has an excellent water-stopping effect even for aqueous liquids containing salts such as urine and cement water, its pH is in the neutral range, its water absorption capacity does not decrease even at high temperatures, and it has excellent heat resistance. .. Therefore, the water-stopping effect is maintained for a long period of time and other materials are not damaged. Suitable for tape, waterproof tape for concrete, seal tape for civil engineering, seal tape for agriculture and horticulture, seal tape for medical use.

[Brief description of 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 absorbent composition or crosslinked polymer (A) ． ． Non-woven fabric 5. ． ． Perforated lid 6. ． ． Distance sensor

Claims (6)

[Claims] 1. A molar ratio of at least one (meth) acrylic compound selected from the group consisting of (meth) acrylic acid and (meth) acrylic acid salt to (meth) acrylamide is 1: 9 to 5: 5. (Meth) acrylic acid and (meth) acrylic acid based on 100 parts by weight of a cross-linked polymer (A) obtained by polymerizing a monomer mixture consisting of 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 agent composition comprising (B) in an amount of 0.1 to 50 parts by weight. 2. The (meth) in the crosslinked polymer (A).
The molar ratio of acrylic acid to (meth) acrylate is 5: 5
The composition of claim 1, wherein the composition is ˜0: 10. 3. The crosslinked polymer (A) has a water absorption rate of 8 minutes or less, which is represented by the time required to reach 90% of the equilibrium water absorption capacity for artificial seawater, and a water absorption capacity for the artificial seawater of 8 times or more of its own weight. And the gel consistency is 0.6 × 1
The composition according to claim 1, which is 0 ^{5 to} 2.5 × 10 ⁵ 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) acrylic acid salt in (B) is 7: 3 to 10: 0. 5. A composite waterproof material in which the water absorbing agent composition is supported on a base material. 6. The composite waterproof material according to claim 5, wherein the base material is a tape-shaped material.