JPH0830180B2 - Water-swellable water blocking material - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a water-swellable water-stop material. More specifically, the present invention, when expanded by absorbing water, the gel does not fall off or elute, and has a good water absorbing ability even for an aqueous solution containing an electrolyte, such as expansion due to water quality. The present invention relates to a water-swellable water-stop material having a small difference in sex.

Conventional technology Water-stopping materials are used in civil engineering and construction work for mortar, concrete construction and cracks in water pipe connections.
It is widely used to stop water leakage by filling gaps that cause water leakage such as cracks and gaps.

As such a waterproof material, conventional rubber, plastic,
Although materials made of easily deformable water resistant materials such as Buchiyumen have been used, these materials cannot respond to changes in the gap when they are used for a long period of time, resulting in reduced impact resilience or creep phenomena. There is a drawback that the water effect is insufficient.

Therefore, as a remedy for such drawbacks,
Water-swellable composition, for example super absorbent resin, diene rubber,
A vulcanizing agent, a vulcanization accelerator, a filler, a vulcanized product of a mixture such as an antioxidant, a resin composition that expands in contact with water has been developed, or such a water-swellable composition,
It has been proposed to combine a non-swelling composition such as a diene rubber, a vulcanizing agent, a vulcanization accelerator, a filler, and a vulcanizate of a mixture of an anti-aging agent, etc. to stop water (Japanese Patent Application Laid-Open No. S60-187200).
57-108143, JP-A-57-135160).

Further, a water-swellable composition in which a highly water-absorbent resin is contained in a flexible plastic such as ethylene-vinyl acetate copolymer is also known (JP-A-55-3424).

Further, a water-swellable substance obtained by compounding a rubber with a water-swellable urethane resin and curing it (JP-A-57-23654), a soft resin or a rubber compounded with a highly water-absorbent resin and a water-swellable urethane prepolymer. Water-absorbing and water-retaining material (JP-A-59-
120653), a water-swellable elastomer composition (JP-A-60-55041) obtained by mixing an elastomer, a water-absorbent resin, and a water-soluble resin such as polyethylene oxide.

A water-stopping material composed of such a water-swellable composition rapidly expands by touching water and closes the leaking gap due to its high expansion pressure, so that effective water-stopping is performed, so It is desirable.

However, in a water-stopping material composed of a conventional water-swellable composition, when it absorbs water and expands, the gel of the superabsorbent resin contained therein falls off, or the water-soluble component elutes. There is a problem that the meat becomes lean and the water absorption capacity for an aqueous solution containing an electrolyte is remarkably smaller than that for ordinary water, resulting in poor water-stopping performance for seawater. are doing.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention improves the drawbacks of the water blocking material composed of such a conventional water-swellable composition, and when it absorbs water and expands,
The gel does not fall off or elute, and also has a good water absorption capacity for aqueous solutions containing electrolytes.
The purpose of the present invention is to provide a water-swellable water-stop material having a small difference in swellability depending on the water quality.

Means for Solving the Problems As a result of various researches, the present inventors have combined an elastomer with a hydrophilic urethane prepolymer, a liquid rubber of a certain kind, or polyethylene oxide and a co-absorbent resin in predetermined proportions. As a result, they have found that the object can be achieved, and have completed the present invention based on this finding.

That is, in the present invention, 50 to 150 parts by weight of the hydrophilic urethane prepolymer (B) is added to 100 parts by weight of the elastomer (A).
5 to 100 parts by weight of (C) hydroxyl group-containing liquid rubber or polyethylene oxide or both, and (D) 5 to 100 parts by weight of highly water-absorbent resin having a water absorption capacity of 20 times or more of its own weight against distilled water. The present invention provides a water-swellable water-stop material formed by molding a composition containing a part.

In the present invention, the elastomer used as the component (A) is a natural rubber, a synthetic rubber, a flexible synthetic resin, or the like, and examples of the synthetic rubber include polyisoprene rubber, polybutadiene rubber, and styrene-diene random copolymer rubber. , Acrylonitrile-diene highly polymerized rubber, chloroprene rubber, isobutylene-isoprene copolymer rubber, ethylene-propylene-diene copolymer rubber, and other diene rubbers. Further, as the flexible synthetic resin, for example, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene-vinyl acetate copolymer,
Examples thereof include soft polyvinyl chloride and polyurethane.
These elastomers may be used alone or in combination of two or more.

In the present invention, the hydrophilic urethane prepolymer used as the component (B) is a water-swellable urethane prepolymer containing a terminal isocyanate group, and examples thereof include ethylene oxide-prepylene having a hydroxyl equivalent of 400 to 6000. Oxide random or block polymer polyoxyalkylene glycol obtained by reacting a polyisocyanate compound by a conventional method, the propylene oxide component / ethylene oxide component weight ratio is 7/3 ~ 0
/ 10 and the free isocyanate group content is in the range of 1 to 12% by weight, preferably 2 to 8% by weight, but is not limited thereto.

This urethane prepolymer may be used as it is, or if desired, it may be partially cured by a conventional method with a curing agent such as water or an amine-based or polyol-based material to be used as a paste. As the curing agent used at this time,
For example, 4,4'-methylenebis (2-chloroaniline),
1,4-butanediol, hydroquinone-bis (β-hydroxyethyl) ether, resorcinol-bis (β-
Hydroxyethyl) ether, 1,2-bis (2-aminophenolthio) ethane, trimethylene glycol-di-p-aminobenzoate, and the like, which may be used alone or in combination of two or more. May be.

In the present invention, as the component (C), a liquid rubber containing a hydroxyl group, polyethylene oxide, or both are used.

Examples of the hydroxyl group-containing liquid rubber include liquid polybutadiene rubber, liquid styrene-butadiene rubber, liquid butadiene-acrylonitrile rubber, and liquid chloroprene rubber, which contain a hydroxyl group as a terminal functional group.

On the other hand, polyethylene oxide has the general formula HOCH a water-soluble resin having hydroxyl groups at both ends represented by _{2 CH 2 O n CH 2 CH} 2 OH, is used as a normal molecular weight from 100,000 to 5,000,000.

In the present invention, the highly water-absorbent resin used as the component (D) needs to have a water absorption capacity for distilled water of 20 times or more, preferably 50 to 800 times its own weight in order to improve water swellability. Is blended with.

Examples of such superabsorbent resin include commercially available starch-polyacrylate superabsorbent resin, cross-linked polyacrylate obtained by reverse phase polymerization in an organic solvent, vinyl alcohol and acrylic acid. And a super absorbent polymer obtained by cross-linking the reaction product of the basic substance of the copolymer of isobutylene and maleic anhydride. Among them, in particular, from the viewpoint of durability of the water blocking material to be obtained, an α, β-unsaturated compound having one or two carboxyl groups or groups capable of being converted in the molecule is a monomer component. A highly water-absorbent resin obtained by crosslinking the polymer contained as above with a crosslinking agent is suitable.

In the present invention, the mixing ratio of these components is 100 parts by weight of the elastomer (A),
50 to 150 parts by weight of the component (B) hydrophilic urethane prepolymer, 5 to 100 parts by weight of the component (C) liquid rubber or polyethylene oxide, or 5 to 100 parts of the component (D) superabsorbent resin. It is necessary to set the range of parts by weight.

An example of a preferred method for producing the water-swellable water-stop material of the present invention will be described. A hydrophilic urethane prepolymer, liquid rubber or polyethylene oxide, and a superabsorbent resin are mixed in predetermined amounts in an elastomer, and if necessary, For example, after adding additive components such as a curing agent, an antioxidant, an ultraviolet absorber, a reinforcing agent, an inorganic filler, a softening agent, a plasticizer and a coloring agent and thoroughly kneading, the resulting composition is extruded or pressed. The water blocking material is obtained by molding.

At this time, the hydrophilic urethane prepolymer may be partially cured with a curing agent in advance and used in the form of a paste. When a diene rubber, for example, is used as an elastomer, the composition may further contain diene. It is preferable to vulcanize and mold by adding other additive components that are usually used for rubbers, vulcanizing agents for diene rubbers, vulcanization accelerators, vulcanization aids and the like.

By this molding operation, the hydroxyl group or carboxyl group in the liquid rubber or the hydroxyl group in polyethylene oxide reacts with the isocyanate group in the urethane prepolymer, and the water-swellable substance is uniformly dispersed in the elastomer.

EFFECT OF THE INVENTION The water-swellable water-stop material of the present invention has good water-swellability, and when it absorbs water and expands, the gel does not fall off or elute, and an aqueous solution containing an electrolyte. It also has a good water-absorbing ability and has excellent characteristics such as no difference in expandability depending on the water quality.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples.
The present invention is not limited in any way by these examples.

 The expansion ratio and the retention rate were determined as follows.

That is, a sample having a thickness of 3 mm and a size of 20 × 20 mm was cut out from the obtained molded body, dipped in each water for 30 days, and the expansion ratio and the retention rate were determined by the following equations.

Example 1 and Comparative Examples 1 and 2 Using the respective components in the proportions shown in the attached table, roll kneading was carried out at room temperature for 15 minutes, followed by press molding at 170 ° C. for 10 minutes to obtain a molded body having a thickness of 3 mm.

Physical properties such as tensile strength, elongation, and hardness, weight expansion ratio, and retention rate of this molded product were determined. The results are shown in the table.

Examples 2, 3 and Comparative Examples 3, 4 Chloroprene, natural rubber, additive components such as vulcanizing agent, and polyethylene oxide were roll-kneaded at 80 ° C. for 15 minutes at a ratio shown in another table, and then the remaining components shown in the table at room temperature. The ingredients were further roll kneaded. Then, a molded body having a thickness of 3 mm was prepared in the same manner as in Example 1, and the physical properties, the weight expansion ratio and the retention rate were determined. The results are shown in the table.

Example 4 Each urethane prepolymer component and LCR in advance
FH-050 was mixed in the proportions shown in the attached table and stirred for 1 hour to prepare a paste-like cured product.

The remaining components other than the above components were roll-kneaded at a ratio shown in the attached table at 80 ° C. for 15 minutes, and then the paste-like cured product was further roll-kneaded at room temperature. Then, a molded body having a thickness of 3 mm was prepared in the same manner as in Example 1, and the physical properties, the weight expansion ratio and the retention rate were determined. The results are shown in the table.

The composition of synthetic seawater used in the test is as follows.

Synthetic seawater NaCl 27.213g / MgCl ₂ 3.807 MgSO ₄ 1.658 CaSO ₄ 1.260 K ₂ SO ₄ 0.863 CaCO ₃ 0.123 MgBr ₂ 0.076 As can be seen from this table, all of Examples 1 to 4
The retention rate with respect to the 3.5 wt% NaCl aqueous solution and the 2.5 wt% Ca (OH) ₂ aqueous solution is 40% or more, but all the comparative examples except No. 5 have low retention rates. Comparative Example 5 has a high retention rate,
Water absorption itself is low and not practical.

Claims (2)

[Claims] Claims: (A) 100 parts by weight of the elastomer,
(B) 50 to 150 parts by weight of a hydrophilic urethane prepolymer,
(C) Hydroxyl group-containing liquid rubber and / or polyethylene oxide (5 to 100 parts by weight) and (D) 5 to 100 parts by weight of super absorbent resin having a water absorption capacity of 20 times or more of its own weight against distilled water. A water-swellable water-stop material formed by molding a composition. 2. The waterproof material according to claim 1, wherein the highly water-absorbent resin has a water absorption capacity for distilled water of 50 to 800 times its own weight.