JPS6318983B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for reliably connecting sheets with each other with good workability, and in particular to a method of connecting sheets with each other using a hot melt adhesive or the like to connect large sheets such as waterproof sheets disposed in a tunnel. This invention relates to a method of connecting using an adhesive that melts.

Conventionally, in tunnel lining sections, as shown in Figure 1, in order to prevent spring water from the ground a side from leaking through the primary lining concrete b and into the secondary lining concrete c side, A waterproof sheet d is placed between the primary concrete lining b and the secondary concrete lining c.

When installing tarpaulin sheets, one tarpaulin sheet is connected to another tarpaulin sheet one after the other, but if there is even a slight gap at the connection point, spring water from the ground may leak. Since leakage occurs to the secondary lining concrete through this gap, it is desirable to connect the sheets in a watertight manner. Furthermore, when connecting sheets, it is also desired that the sheets be easily aligned with each other and that the sheets be connected reliably with a simple operation.

The present invention has been made in view of the above circumstances, and is made by forming at least the connecting portion of one or both of the sheets to be connected to each other transparent, and heating the connecting portion with a transparent material having a melting point lower than that of the sheet. At the same time as applying a melting adhesive, the entire surface or a portion of the surface of the adhesive layer is made opaque by forming fine irregularities with knurling or the like, and then the adhesive layer is made so that the opaque portions become opaque. By heating and bonding until it becomes transparent,
It is possible to carry out the connection work while checking whether or not the sheets are reliably adhered to each other using whether or not the opaque portion becomes transparent as an indicator.Therefore, this allows the sheets to be reliably adhered to each other without error. It is an object of the present invention to provide a method for connecting sheets that can connect the sheets reliably without forming any gaps or the like, thereby ensuring perfect watertightness at the connection point. do.

2 to 4 for one embodiment of the present invention.
This will be explained with reference to the figures.

In the figure, 1 and 1' are sheets that are connected to each other, and in the present invention, these sheets 1 and 1' may be a single plastic sheet such as polyethylene or polypropylene, a composite sheet of two or more types of plastic, or a metal sheet. Laminated sheets etc., which are appropriately combined, are used.

Adhesive layers 2 and 2' are formed on the sheets 1 and 1' at their connection points (in the drawings, one end in the width direction of one surface of the sheets 1 and 1').
Here, the connecting portions of the sheets 1, 1' are formed transparent so that the adhesive layers 2, 2' can be seen through when they are connected. In addition, adhesive layer 2,
2' is formed by continuously applying adhesive to one end in the width direction of one surface of the sheets 1, 1' from one end edge in the length direction to the other end edge in the length direction. As for sheet 1, 1'
An adhesive that has a melting point lower than that of the adhesive and melts when heated, such as a transparent hot melt adhesive, is used. In this case, adhesives include those whose main component is ethylene-vinyl acetate copolymer mixed with resins such as rosin ester, paraffin, and wax, and those whose main component is polyamide. Any material may be used as long as it has a melting point lower than that of the sheet and can be bonded by heating, and is appropriately selected depending on the type of sheet, but it is particularly preferable to have a melting point of 5° C. or lower than the melting point of the sheet. For example, when an ethylene-vinyl acetate copolymer sheet containing 15 mol% of ethylene-vinyl acetate is used as an adhesive, ethylene-vinyl acetate 30~
50 parts of rosin acid ester, 30 to 50 parts of rosin acid ester, and 10 to 30 parts of 145% wax are preferably used.

Further, the surfaces of the adhesive layers 2 and 2' are each formed with fine irregularities by knurling, thereby making the entire surface opaque.

When connecting the sheets 1 and 1', the adhesive layers 2 and 2' are brought into contact with each other as shown in FIG. (The heating temperature is preferably higher than the melting temperature of the adhesive layers 2, 2' and lower than the melting temperature of the sheets 1, 1'.) In this case, the sheet 1 or While observing the adhesive layers 2, 2' visually through the transparent connection point 1', heat the adhesive layers 2, 2' until the surface opaque portions (irregularities) 3, 3' become transparent. It is something that performs work.

According to the method for connecting the sheets 1 and 1', the adhesive layers 2 and 2' are bonded to the sheets 1 and 1' using an adhesive that melts when heated, such as a hot melt adhesive having a lower melting point than the sheets 1 and 1'. , and its surface is made opaque by forming fine irregularities by knurling, so when the adhesive layers 2 and 2' are bonded together by heating, the surface opaque portion (unevenness) is made opaque. ) It is possible to easily and clearly detect whether or not the adhesive layers 2 and 2' are melted and bonded to each other by using as an indicator whether or not the adhesive layers 2 and 3' are transparent. 2′ opaque portion 3,
By heating and bonding until the adhesive layer 3' becomes transparent, the adhesive layers 3 and 3' can be melted and bonded without error. Furthermore, in this case, the completion of the bonding work can be detected by detecting that the opaque portions 3, 3' have become completely transparent, and therefore the adhesive layers 2, 2' are completely mutually transparent. Of course, there is no need to make the mistake of stopping the process before the adhesive layer 2, 2' is completely bonded, and to continue the process after the adhesive layers 2, 2' are completely bonded, resulting in excessive connection (adhesive area) 4.
There is no inconvenience caused by heating.

Therefore, since the adhesive layers 2 and 2' can be completely bonded and integrated without any mistakes, the connecting part (adhesive part) 4 becomes completely watertight, and there is no possibility of water leaking from the connecting part 4. This is not the case at all, and for this reason, the method for connecting the sheets 1 and 1' described above can be suitably adopted as a method for connecting waterproof sheets disposed inside a tunnel.

On the other hand, if the adhesive layer does not have opaque parts due to minute irregularities, it is difficult to detect whether it has completely adhered or not, and therefore the adhesion work must be performed before the adhesive layer is completely adhered. The process may stop or may continue to work even after complete adhesion, resulting in the adhesive layer not bonding reliably and leaving gaps or gaps at the connection. , there is a risk of water leaking from the connection, and the object of the present invention cannot be achieved.

Furthermore, according to the above connection method, the sheets 1, 1'
Since the adhesive layers 2 and 2' are formed in advance on the
It can be easily bonded by simply heating at the construction site, and the adhesive layers 2, 2'
Mutual positioning can be easily performed, and bonding work can be performed using the transparency of the opaque parts 3 and 3' as a guide, so workability is good and the work of connecting sheets can be performed efficiently. It is something that can be done. Therefore, even when working inside a tunnel, the connection work can be carried out very efficiently, and it does not involve complicated or troublesome operations, so from this point of view, the use of waterproof sheets inside tunnels is very effective. This is a very advantageous connection method.

In the above embodiment, a case has been described in which the ends in the width direction of the sheets 1 and 1' are connected to each other, but the same applies to the case in which the ends in the length direction are connected to each other. Further, in the above embodiment, the adhesive layers 2, 2'
The opaque portion was formed on the entire surface by forming fine irregularities on the entire surface, but these fine irregularities are not limited to being formed by knurling, and can take various forms. The unevenness does not necessarily have to be formed on the entire surface, but may be formed partially to make the surface partially opaque.
However, in this case, it is preferable that the fine irregularities, and therefore the opaque portion 3, be formed continuously along the length of the adhesive layer 2, as shown in FIG. 5, so that complete adhesion can be achieved. It is possible to reliably judge whether the entire adhesive layer 2 has been applied or not. Furthermore, in the above embodiment, both sheets 1, 1'
Adhesive layers 2 and 2' are formed on each sheet, and these adhesive layers 2 and 2' are bonded to each other. However, in some cases, one adhesive layer 2 may be directly bonded to the other sheet 1'. In addition, when bonding the sheets 1 and 1', it is also possible to bond them by butting as shown in FIG. 6, and other configurations may be modified in various ways without departing from the gist of the present invention. No problem.

As explained above, the present invention is a method of connecting two sheets to be connected to each other using an adhesive that melts by heating, and in which at least the connecting portion of one or both of the sheets is made transparent. Then, an adhesive layer is formed at the connection point using a transparent adhesive that melts when heated and has a melting point lower than that of the sheet, and fine irregularities are formed on the surface of this adhesive layer to bond the area. to make it opaque,
Next, the adhesive layer was heated until the opaque portion became transparent while visually observing the adhesive layer through the transparent connecting portion of the sheet, so that the two sheets were connected to each other, so that the opaque portion became transparent. It is possible to perform the connection work while checking whether or not the sheets are reliably adhered to each other using whether or not the sheets are adhered to each other as an indicator. The watertightness at the connection part is good, and therefore it is suitably employed as a connection method for waterproof sheets, especially waterproof sheets disposed in tunnels.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the arrangement of waterproof sheets in the tunnel lining section, Fig. 2 is a perspective view showing an example of the sheet used in the implementation of the present invention, and Fig. 3 is a cross-sectional view showing the arrangement of the waterproof sheets in the tunnel lining section. FIG. 4 is a partially omitted cross-sectional view showing an example of a state in which two sheets are connected to each other; FIG. FIG. 6 is a plan view showing another example of the portion, and a partially omitted sectional view showing another manner of connecting two sheets. 1, 1'... Sheet, 2, 2'... Adhesive layer, 3... Opaqueized portion, 4... Connection portion.

Claims (1)

[Scope of Claims] 1. A method of connecting two sheets to be connected to each other using an adhesive that melts when heated, the method comprising forming at least the connecting portion of one or both of the sheets transparent, In addition, an adhesive layer is formed at the connection point using a transparent adhesive that melts when heated and has a melting point lower than that of the sheet, and fine irregularities are formed on the surface of this adhesive layer to make that part opaque. and then heating the adhesive layer until the opaque portion becomes transparent while visually observing the adhesive layer through a transparent connecting portion of the sheet, thereby connecting the two sheets to each other. . 2. The method according to claim 1, wherein the fine irregularities are continuously formed along the length direction of the adhesive layer.