JPS597511B2 - Gooseiji Yushu-Bunai Menheno - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of applying an adhesive to the inner surface of a synthetic resin tube.

In particular, it relates to a method for easily and continuously applying a heat-activated adhesive to the inner surface of a synthetic resin tube to a desired thickness. Synthetic resin tubes, especially heat-shrinkable synthetic resin tubes with adhesive applied to the inner surface, are called cap sealing materials,
It has come to be used for applications such as electric wire covering materials. However, until now, there has been no method for efficiently and easily applying adhesive to the inner surface of a synthetic resin tube. The present inventors conducted various researches to develop a method for simply and efficiently applying adhesive to the inner surface of a synthetic resin tube, and as a result, they completed the present invention, which is significantly superior to conventional methods.

The method of applying adhesive to the inner surface of a synthetic resin tube of the present invention is as follows:
A heat-activated adhesive inserted into a synthetic resin tube in advance is melted by heating, and then the tube is continuously pulled through a gap between at least a pair of rolls to form a coated layer of adhesive on the inner surface of the tube. This method is characterized by forming.

When using this method, heat-activated adhesive can be easily applied continuously and quickly to the inner surface of a synthetic resin tube using a simple device and operation, and the coating thickness, coating position, and shape can be freely controlled. Can be adjusted.

The present invention will be explained in detail on the basis of the accompanying drawings, which show examples of embodiments thereof.

Fig. 1 is a schematic perspective view showing the state in which adhesive is applied to the inner surface of a synthetic resin tube according to the present invention, and Fig. 2 is an enlarged longitudinal sectional side view of the vicinity of the applicator roll in Fig. 1. It is. 1 and 2, 1 is a synthetic resin tube to which adhesive is applied, 2 is a take-up roll, 3 is a heating bath, 4 is an application roll, 5 is a cooling bath, 6 is a pair of application rolls 4 and 4, 7 is a nip roll, 8 is an adhesive-coated tube, 9 is a rolled roll thereof, 10 is a heat-activated adhesive in a molten state, and 11 is an adhesive coating layer applied to the inner surface of the tube. are shown respectively. Moreover, the arrow in the figure indicates the rotation direction of the roll. As shown in FIGS. 1 and 2, the synthetic resin tube 1 after passing between the take-up rolls 2 and 2 is filled with heat-activated inoculation material 1 and 2. The adhesive is kept in a molten state by a heating bath 3. In this way, when the synthetic resin tube 1 with the molten heat-activated adhesive sealed therein is passed through the gap 6 between the pair of applicator rolls 4 and 4 and taken off, the excess adhesive is squeezed out. After passing through the gap 6, an adhesive coating layer 11 having a thickness corresponding to the thickness of the gap 6 is formed on the inner surface of the tube. Next, a predetermined internal pressure is applied to the inside of the tube after passing through the gap 6 between the applicator rolls, so that the tube is stretched and maintained in a cylindrical shape.
When this tube, which is maintained in a cylindrical shape and has an adhesive coating layer 11 provided on its inner surface, is passed through a cooling bath 5, the adhesive coating layer 11 is cooled and solidified on the inner surface of the tube. The tube 8 with the solidified adhesive 11 is then passed between the nip rolls 7 and folded and wound into a roll 9. In this case, since the adhesive coating layer 11 is folded after being cooled and solidified, there is no risk of the adhesive coating layers adhering to each other. The thickness of the adhesive layer is determined by coating rolls 4 and 4.
It can be arbitrarily adjusted by adjusting the thickness of the gap 6 and controlling the melt flow state by adjusting the heating temperature of the adhesive. FIG. 3 is an enlarged front view of a pair of applicator rolls used in another embodiment.

Since the applicator rolls 4 and 4 are provided with two grooves 12 each having a predetermined width and depth at opposing positions, the gap 6 in the groove part is larger than that in the other part of the gap between the rolls 4 and 4. gap 6'. Therefore, if the application roll is used and the collection is carried out according to the method described above,
It is possible to easily apply adhesive to a predetermined width and thickness only to the inner surface of the film in the gap 6' without applying any adhesive to the inner surface of the film in the gap 6', and as a result,
Four vertical stripes of adhesive coating layer can be continuously formed on the inner surface of the tube. If a square can is heat-shrink wrapped using a tube having four adhesive coating layers,
Packaging can be carried out by bonding each corner of a square can with adhesive, resulting in an excellent package. The adhesive used in the present invention is a heat-activated solid adhesive, that is, an adhesive that melts when heated and exhibits adhesive properties.

Various heat-activated solid adhesives of this type are known and commercially available, so they can be used as appropriate in the present invention. For example, TOPC
O (trade name of Toyo Ink Co., Ltd.) can be used. Hereinafter, the present invention will be explained in more detail with reference to Examples.

In the embodiment shown in FIG. 1, a polyvinyl chloride tube 1 (diameter 25 mm, thickness 0.225 mm) is pre-filled with an ethylene monovinyl acetate copolymer-based heat-activated adhesive 10 having a softening point of 70°C. After that, the adhesive 1 is compressed with a rubber take-up roll 2, and steam is blown into the heating bath 3.
0 was heated to 98-100°C and kept in a molten state.

In this state, the tube 1 was passed between rubber applicator rolls 4 with a nip pressure of 1.5 k9/cm, and the adhesive 10 was applied to the inner surface of the tube 1. The tube 1 is then stretched to a diameter of 50 mm by air pressure between the nip rolls 7.
It is kept in an inflated state and cooled by spraying cooling water at 20° C. in a cooling bath 5 at a speed of 17.3 m/min.
It was taken over. The obtained adhesive coating tube 8 has 10
The shrinkage rate in the radial direction by heating at 0° C. for 5 minutes is 50%, and the thickness of the adhesive coating layer 11 is ? was approximately 10μ.

[Brief explanation of drawings]

Figures 1 and 2 illustrate one example of the embodiment of the present invention, with Figure 1 showing a schematic perspective view of the application state, and Figure 2 showing an enlarged view of the vicinity of the applicator roll in Figure 1. It is shown in a longitudinal side view. Further, FIG. 3 is a front view of a coating roll used in another embodiment. The symbols in each figure indicate the following. 1...Synthetic resin tube, 2
...Take-up roll, 3...Cut heat bath, 4
... Application roll, 5 ... Cooling bath, 6.
...Applying roll gap, 7...Nippro roll, 8...Adhesive application tube, 9...
・Rolled material of the same tube, 10... Heat-activated adhesive in molten state, 11... Adhesive coating layer, 12... Provided on the coating roll. groove.

Claims (1)

[Claims] 1 A heat-activated adhesive inserted into a synthetic resin tube in advance is melted by heating, and then the tube is passed through a gap between at least a pair of rolls and continuously taken off to form a coating layer of adhesive on the inner surface of the tube. A method of applying adhesive to the inner surface of a synthetic resin tube, characterized by forming an adhesive on the inner surface of a synthetic resin tube.