JPH02206620A - Strip of water-swelling substance - Google Patents

Abstract

PURPOSE:To obtain the subject substance to be bonded to or filled in the gap of a joint, etc., of steel sheet piles to completely stop water with simple operation by applying a specific water-swelling coating material to a releasing paper and peeling the coating after drying. CONSTITUTION:The objective substance can be produced by dispersing and mixing (A) a highly water-absorbing polymer in (B) an organic solvent solution of a thermoplastic elastomer, applying the obtained water-swelling coating material to a releasing paper and peeling the coating after drying. Preferably, the component A is carboxymethyl cellulose, etc., and the component B is chloroprene rubber, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a strip of water-swellable material. More specifically, the present invention relates to a band-shaped water-swellable material that is bonded or filled into gaps such as joints of steel sheet piles, segments for civil engineering and building materials, or fillers in order to prevent water leakage during civil engineering work.

[Conventional technology]

Conventionally, for example, in civil engineering work to stop water using steel sheet piles,
Water leakage from the joints of the steel sheet piles was a major cause of construction delays.

As a countermeasure, methods such as double driving of steel sheet piles were used, but this had the disadvantage of requiring enormous construction costs. Therefore, currently, water-expandable paint is applied to the joints of steel sheet piles in advance, and then the water-expandable paint is poured into water or soil.The water-expandable paint comes into contact with water and expands, filling the gaps between the joints and stopping the joints. The method of watering is used.

On the other hand, as a method for water-stopping gaps such as segments or sealing parts for civil engineering and construction materials, methods of filling the gaps with synthetic resin paints such as epoxy, water-swellable paints, asphalt, etc. have been used.

[Problem to be solved by the invention]

However, since all of these conventional water-swellable paints are applied by brushing, it is extremely difficult to coat the inside of the joint to a uniform thickness.

If the coating film is too thin, the water-swellability will be low, resulting in insufficient water-stopping properties, and if it is too thick, there will be problems such as peeling of the coating film due to friction between the steel sheet piles when driving the steel sheet piles. Furthermore, it is necessary to dry the paint for at least one day after painting, and if there is a risk of rain during this time, the paint must be covered with a sheet or the like for protection.

In addition, segments for civil engineering construction materials or closures, etc.
Depending on the size and shape of the gap, it may be difficult to fill it with the above-mentioned paint, and it may take a long time to dry after filling.

[Means to solve the problem]

As a result of intensive research to resolve the drawbacks of the conventional water-swellable paints, the inventors of the present invention have developed a solution for civil engineering by forming the water-swellable paint into a strip of uniform thickness and adhering it to the joints of steel sheet piles. It was discovered that this purpose could be achieved by filling gaps in building material segments or closures, etc., and this led to the completion of the present invention.

That is, the present invention provides a water-swellable strip obtained by coating a release paper with a water-swellable paint prepared by dispersing and mixing a super absorbent polymer in an organic solvent solution of a thermoplastic elastomer, drying it, and then peeling it off from the release paper. Concerning matter.

The superabsorbent polymer used in the production of the water-swellable paint, which is the raw material for the water-swellable strip material of the present invention, is a polymer having a carboxyl group, such as carboxymethyl cellulose, vinyl acrylate alcohol copolymer, or polyacrylic acid. It is a sodium salt.

Similarly, the thermoplastic elastomer needs to be dissolved in an organic solvent to become a fluid, in order to uniformly disperse and mix the super absorbent polymer into the thermoplastic elastomer.

Furthermore, the thermoplastic elastomer has rubber elasticity and as a water-swellable strip material has a temperature of at least 2 k when expanded.
It is necessary to have water pressure resistance of g/Ci, and examples of materials that satisfy this requirement include chloroprene rubber, styrene-butadiene rubber, ethylene-vinyl acetate copolymer, and polystyrene-polybutadiene block copolymer.

As the organic solvent for dissolving these thermoplastic elastomers, aromatic hydrocarbons such as toluene and xylene are suitable.

To produce the band-shaped water-swellable material of the present invention, first, a superabsorbent polymer is dispersed and mixed in an organic solvent solution of a thermoplastic elastomer to form a water-swellable paint.

Furthermore, in order to make this into a strip, this water-swellable paint is applied to a release paper using a film applicator, roll coater, curtain flow coater, etc. so that the thickness of the dry film is about 1 inch, and after drying. , peel it off from the release paper and cut it to a certain width.

To bond this strip of water-swellable material to steel sheet pile joints,
First, a pressure-sensitive adhesive is applied to the joint of the steel sheet pile, and the water-swellable material strip obtained as described above is adhered thereon, or alternatively, a pressure-sensitive adhesive is first applied to a release paper, and then The uncut band-shaped water-swellable material is crimped on top of the material, and while both are in the crimped state, they are peeled off from the release paper, cut, and bonded to a joint of steel sheet piles.

In addition, if antifriction agents such as glass beads, molybdenum disulfide, zinc oxide, or fluororesin are sprayed and adhered to the surface of the release paper during the initial stage of drying in the production of water-swellable material strips, it may cause problems when driving steel sheet piles. Frictional resistance between the steel sheet piles can be reduced.

In addition, the band-shaped water-swellable material of the present invention is applicable not only to the above-mentioned steel sheet piles, but also to concrete sheet piles, Ill! Steel sheet piles can also be used for similar purposes, and are also effective as water-stopping materials for steel or concrete segments or sealing parts.

〔Effect of the invention〕

The band-shaped water-swellable material of the present invention can completely seal the joints of steel sheet piles with the simple operation of simply gluing it to the joints of steel sheet piles. There is no flammability or toxicity due to the use of organic solvents, unlike when applying water-swellable paints by brushing. After bonding, steel sheet piles can be driven immediately.

In addition, compared to the case where water-swellable paint is applied by brushing, there is no unevenness in the thickness of the paint film or unpainted areas, so excellent water-stopping properties can be maintained.

In this way, the band-shaped water-swellable material of the present invention not only improves the workability of retaining work using steel sheet piles, but also completely prevents water leakage from the joints of steel sheet piles. This is an excellent product that can improve the efficiency and safety of cofferdam construction in rivers and oceans.

Similarly, excellent effects can be exhibited in the construction of segments for civil engineering and building materials or in the construction of stoppers for sealing parts.

[Examples and comparative examples]

Hereinafter, the present invention will be explained in more detail with reference to Examples and Comparative Examples. In Examples, parts refer to parts by weight, and % refers to % by weight.

Example 1 As a thermoplastic elastomer, neoprene WRT (manufactured by Showa Den EduPont Co., Ltd.), which is chloroprene rubber, was used as a thermoplastic elastomer.
00 parts were dissolved in 400 parts of xylene. To this was added 250 parts of Celogen 3H (manufactured by Dai-Kogyo Seiyaku Co., Ltd.), which is carboxymethyl cellulose, as a super absorbent polymer, and the mixture was dispersed and mixed using Daysilver to obtain a water-swellable paint.

This was applied to release paper using a film applicator with a gap of 2.5 mm, dried at 80° C. for 30 minutes, and then peeled off from the release paper to obtain a strip of water-swellable material with a thickness of 0.8 am.

Next, 50 parts of neoprene WRT and 50 parts of rosin-modified glycerin ester Harinister T (manufactured by Kasei Kogyo Co., Ltd.) were dissolved in 400 parts of xylene to make a pressure-sensitive adhesive, and this was applied using a film applicator with a gap IIm. It was coated on release paper and dried at 80°C for 30 minutes.

The previously obtained strip of water-swellable material was layered and crimped onto this pressure-sensitive adhesive coating, peeled off from the release paper in the crimped state, cut to a diameter of 12 cSI, and coated with adhesive in the strip of water. An expansive material was obtained.

With this adhesive strip of water-swellable material.

The following water pressure test was conducted.

That is, first, a band-shaped water-swellable material with an adhesive was adhered to the inside and outside of a joint of two FSP type steel sheet piles each having a length of 50 aI, with the pressure-sensitive adhesive side facing inside.

Next, one of the two steel sheet piles was longitudinally fused into two pieces, and each joint portion was joined to the joints on both sides of the remaining uncut steel sheet piles.

The water pressure test was conducted using the testing apparatus shown in FIG.

That is, the steel sheet piles joined with the joints 3 are placed horizontally so that the steel sheet piles 1 that are not fused in the center are facing up, and on top of that, a semi-cylindrical sheet pile with a water/air inlet 5 in the center of the upper part is placed. The cover 4 is fixed to the welded steel sheet piles 2a and 2b with bolts 6 to seal the contact surface, and both cut surfaces of the joined steel sheet piles (also both cut surfaces of the cover 4) (perpendicular to the plane of the paper) (both end faces in the direction) were sealed with two sealing plates 7.

Thereafter, when water was injected from the water/air inlet 5, water leaked from the joint 3 at first, but water stopped leaking after one hour.

In addition, the water/air inlet 5 is equipped with a 24-hour compressor.
I pressurized the water surface by injecting air, but the pressure was 4 kg/, ff.
There was no water leakage even at a pressure of 1 liter.

Comparative Example 1 The water-swellable paint obtained in Example 1 was applied with a brush to the inside and outside of a joint between two steel sheet piles similar to those used in Example 1. The coating thickness was the same as the thickness of 0.8 mm in the case of the band-shaped water-swellable material in Example -.

After drying these two steel sheet piles in the air for 4 hours, one of them was cut vertically into two pieces according to Example 1 and joined to other steel sheet piles. Due to the non-uniformity, there was considerable frictional resistance during bonding and the coating partially peeled off.

When the steel sheet piles joined in this way were tested in accordance with the water pressure test in Example 1, it was found that water initially leaked from the joints as in Example 1, but after that the water leakage stopped. It took 3 hours. Furthermore, when air is injected after 24 hours.

Water leaked at a pressure of only 1 kg/a#.

This is due to the non-uniformity of the paint film thickness due to uneven brushing when applying the water-swellable paint, the peeling of the paint film when joining steel sheet piles due to the non-uniformity of the paint film thickness, and the drying time of the paint film of 4 hours. This is thought to be because the swollen coating film could not withstand water pressure because the coating film was too short to form a rubber-elastic coating.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of the testing apparatus used in the water pressure test of the present invention, showing the state when water no longer leaks from the joints of steel sheet piles. 1: Steel sheet piles that do not melt 2a, 2b: Melt-cut steel sheet piles 3: Joint 4: Cover 5: Water/air inlet 6: Bolt 7: Sealing plate

Claims (1)

[Claims] A band-shaped water-swellable material obtained by coating a release paper with a water-swellable paint made by dispersing and mixing a highly water-absorbing polymer in an organic solvent solution of a thermoplastic elastomer, drying it, and then peeling it off from the release paper.