JPH04459B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for jointing waterproof sheets underwater, and more specifically, adhesive tape is attached in advance to a pair of sheets that will become the joints of waterproof sheets in the air, and then the joints are jointed underwater. Regarding the method. (Prior Art) Conventionally, waterproof sheets such as vulcanized rubber sheets or resin sheets have been widely used in the field of civil engineering and construction. The other one is 200
Although it is possible to extend up to 300 meters, the width is at most 2 to 10 meters. Therefore, the reality is that these waterproof sheets are joined at a factory or transported to a construction site and then joined together at the site. However, in the case of offshore reclamation, the method of laying joined sheets on the seabed as described above requires joining a wide area of sheets on land, transporting them by ship, and sinking them to the seabed. However, it is extremely troublesome and time-consuming work.
Therefore, underwater jointing of waterproof sheets is the most rational method for construction work in which the above-mentioned wide-area sheets are laid on the seabed or underground. Conventionally, physical fixing methods have generally been used to create underwater joints, such as the riveting method in which adhesive is sandwiched between sheet wraps and metal plates are placed on both sides of the sheet and fixed with rivets; The fastener method, in which the pipe is joined with a fastener, and the concrete-in-pipe method, in which the end of the sheet is inserted into the pipe and filled with concrete, have been proposed, but the riveting method and concrete-in-pipe method require extremely time-consuming underwater work. However, the reality is that the Fastner construction method is currently only in practical use for something similar to a diving suit, so applying it to underwater joints would be expensive, and there would be problems with durability if kept underwater for a long time. It was hot. (Object of the Invention) The present invention addresses this situation and employs chemical fixing means instead of the above-mentioned physical fixing means, which facilitates jointing in water and requires special jigs. This provides a method that allows for easy underwater jointing without using. (Structure of the Invention) That is, the present invention is characterized by adding a vulcanizing agent and a vulcanization accelerator to a rubbery polymer made of ethylene-propylene terpolymer, butyl rubber, or a blend thereof, which has low water absorption in the air. After applying a self-adhesive self-vulcanizing adhesive tape containing a self-adhesive adhesive tape to the ends of both waterproof sheets, the waterproof sheet is submerged in water, and the waterproof sheet is placed in the water with the adhesive tape sandwiched between the waterproof sheets. The point is to join the lap portions by rolling them while overlapping them. The method of the present invention is based on the discovery that adhesive tape is hardly affected by moisture, that is, the adhesive strength between roofing sheets does not decrease in water, but rather improves as the adhesive tape hardens. It can be said that the unique feature is that the previous emphasis on adhesion only in the air was now applied to adhesion in an underwater environment. (Embodiment) The figure is a longitudinal cross-sectional view of an underwater seat joint structure in which the underwater joint method of the present invention is implemented.
First, a waterproof sheet 4 with adhesive tape 3 attached to the end thereof is submerged in water 1, usually on the ground 2 under a water pressure of 10 m or less. Next, the ends of the waterproof sheets 4 are overlapped, and at the same time, the release paper stuck to the surface of the adhesive tape 3 is removed, and the waterproof sheets 4 are joined together by rolling with a rolling pressure roller. Each of these tasks will be performed by divers. The waterproof sheet used in the present invention is, for example, a vulcanized rubber sheet made of ethylene-propylene terpolymer (EPT), butyl rubber (IIR), or a blend thereof, or a resin sheet such as EVA or PVC. In addition, adhesive tapes are naturally vulcanized and have low water absorption, such as EPT, IIR, or other adhesive tapes.
Blends of ERT and IIR are preferred, which include vulcanizing agents, vulcanization accelerators, adhesives and softeners, as well as stearic acid, carbon black,
Inorganic fillers, ZnO, etc. are mixed and blended as necessary. Among these, sulfur, morpholine,
Sulfur-based compounds consisting of sulfur-containing compounds such as disulfide, phosphorus-containing polysulfide, and sulfur chloride; oxime-based products such as p-quinone dioxime and p-p'-dibenzoyl quinone dioxime; or α-cumyl hydroperoxide; Methyl ethyl ketone peroxide, hydrogen peroxide, acetylacetone peroxide, t-butyl hydroperoxide, t
-Peroxides such as butyl peroxybenzoate are included, and the amount of these vulcanizing agents used is usually 1 to 6 parts by weight per 100 parts by weight of the rubbery polymer.
Parts by weight. In addition, 2-mercaptobenzothiazole, dibenzothiazole,
Thiazoles such as disulfide, thiurams such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, dipentamethylenethiuram hexasulfide, or dithiocarbamates such as Zn-di-n-butyldithiocarbamate; Examples include PbO ₂ and trimene base. The amount of these vulcanization accelerators used is usually
The amount is 2 to 10 parts by weight per 100 parts by weight of the rubbery polymer. Furthermore, as adhesives to be mixed, aromatic hydrocarbon resins such as Petrozine (manufactured by Mitsui Petrochemicals), which is a petroleum-based hydrocarbon resin, and aliphatic cyclic carbonized resins such as Hiretsu (manufactured by Mitsui Petrochemicals) are used. Examples include hydrogen, unsaturated hydrocarbon polymers such as Escorets (manufactured by Etsu Chemical Co., Ltd.), hydrocarbon-based tackifying resins such as Taku Ace (manufactured by Mitsui Petrochemical Co., Ltd.), and phenol resins such as phenol formaldehyde resins. The amount of these adhesives used is 30 to 100 parts by weight per 100 parts by weight of the rubbery polymer. Also, known softeners are used with these adhesives, typical examples of which include process oil, polybutene, liquid paraffin, pine tar, and other petroleum-based high-boiling compounds. The amount of these softeners used is 30 to 150 parts by weight per 100 parts by weight of the rubbery polymer. In addition, as a compound for a self-vulcanizing type adhesive tape with a relatively fast vulcanization rate, an oxime such as P-quinone dioxime or P-P'-dibenzoyl quinone dioxime is added to 100 parts by weight of the rubbery polymer. 1-2 parts by weight of vulcanizing agent, 3-4 parts by weight of vulcanization accelerator of _PbO2
parts by weight, 30 to 100 parts by weight of an adhesive, and 30 to 150 parts by weight of a softener such as process oil may be added. On the other hand, the composition of a naturally vulcanizing adhesive tape with a relatively slow vulcanization rate is sulfur, morpholine disulfide,
1 to 3 parts by weight of a sulfur-based vulcanizing agent selected from phosphorus-containing polysulfide, sulfur chloride, etc., 2 to 6 parts by weight of a vulcanization accelerator selected from thiazole, thiuram, or dithiocarbamate, and adhesive. 30 to 100 parts by weight and 30 to 150 parts by weight of a softening agent such as process oil may be added. This adhesive tape must have an initial strength of the joint part of the waterproof sheet, that is, a self-adhesive force of about 1 to 3 kg/25cm.If this adhesive tape does not have this self-adhesive force, it will not be possible to pull the joined waterproof sheet during underwater joint construction. If this happens, the waterproof sheet will shift and deform at the joint. Therefore, in order to satisfy this self-adhesive strength, 30 to 100 parts by weight of an adhesive is added to 100 parts by weight of the rubbery polymer to provide surface tack, and 30 to 150 parts by weight of a softener is added to the adhesive tape. The Mooney viscosity (ML ₁ + ₅ 100°C) must be in the range 4-25. The thickness of this adhesive tape should be 0.5 to 2 mm; if it is more than 2 mm, a step will be created between the waterproof sheets at the joint, making them easy to peel off at the initial stage of joining, which is not preferable. In the present invention, adhesive tape is attached to the joints of both waterproof sheets, and a release paper is pasted thereon, and then these waterproof sheets are submerged in water such as freshwater or seawater. After that, the diver overlaps the joined ends of the waterproof sheets, and at the same time peels off the release paper and rolls the lap part with a rolling pressure roll. For example, it is desirable to improve the adhesive strength between the waterproof sheets and to remove moisture existing between the waterproof sheets. In addition, as time passes, the adhesive tape vulcanizes and the waterproof sheets become even more firmly bonded to each other, making underwater joint construction extremely safe. Since the adhesive tape is flexible and has a certain thickness, it evenly adheres to the waterproof sheet by rolling pressure and sufficiently performs its water-blocking function. Example: Thickness made of the rubber compound shown in Table 1 in the factory
A naturally vulcanized adhesive tape of 1.0 to 1.5 mm, width 100 mm, and Mooney viscosity 5 was formed, and after being stored at 25° C. for 2 days, it was brought to the bonding site. This adhesive tape was attached to the edge (200 mm) of a vulcanized rubber sheet made of a blend of EPT and IIR.
A release paper was attached. 2 pieces of the above waterproof sheets 15~17
The waterproof sheets were submerged in water at a depth of 40 to 50 cm at a temperature of 40 to 50 cm, and the ends of the waterproof sheets were overlapped and simultaneously the release paper was removed and the sheets were rolled using a rolling pressure roller (0.5 kg/cm). After bonding, it was taken out of the water and a peel test was conducted. still,
A test piece for the peel test was punched out of the bonded waterproof sheet to a size of 1 x 6 inches, and this test piece was subjected to a T-peel test using a tensile tester at 20-25°C at a speed of 50 mm/min. The results are shown in Table 2.

【table】

[Table] Destruction (Effects of the Invention) As described above, according to the underwater joint construction method of the present invention, it is possible to perform joints in an underwater environment using a naturally vulcanizable adhesive tape, and the joint construction method according to the present invention is effective against the passage of time. As the adhesive tape hardens as the adhesive tape hardens, the adhesive strength of the tarpaulin sheet increases, so there is no need to use physical fixing means, which has the effect of allowing easy underwater jointing. There is.

[Brief explanation of drawings]

The figure is a longitudinal sectional view of an underwater sheet joint structure in which the underwater joint construction method of the present invention was implemented. 3... Adhesive tape, 4... Waterproof sheet.

Claims (1)

[Claims] 1 Self-adhesive self-adhesive adhesive tape containing a rubbery polymer made of ethylene-propylene terpolymer, butyl rubber, or a blend thereof, which has low water absorption in the air, and a vulcanization agent and vulcanization accelerator. After affixing the waterproof sheets to the ends of both waterproof sheets, the waterproof sheets are submerged in water, and the lap parts are joined by rolling pressure while overlapping the waterproof sheets under water with the adhesive tape sandwiched between them. A method for underwater jointing of a tarpaulin sheet.