JPH0420850Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a heat-shrinkable tube roll that winds up a long heat-shrinkable tube.

(Prior Art) Conventionally, heat-shrinkable tubes are stored and transported in extremely long lengths, so they are handled in the form of rolls that are flattened and wound up. The winding end of the roll remained open as it had been cut.

(Problem to be solved by the invention) Heat-shrinkable tubes shrink significantly when heated, but they also tend to shrink somewhat even at room temperature. Therefore, conventional heat-shrinkable tube rolls tend to tighten over time due to shrinkage. When the heat-shrinkable tube is unwound due to this stress, short-cycle irregularities such as waving and meandering curvature occur, which subsequently causes problems in printing and packaging processes.

(Means for solving the problem) The inventors of the present invention conducted studies to solve the above problem, and found that air penetrated to a considerable depth from the winding end of the heat-shrinkable tube roll. The present invention was developed based on the discovery that the stress of winding acts irregularly due to air pockets and the like, causing undulations and curvature.Hereinafter, the present invention will be explained based on the attached drawings.

As shown in FIG. 1, the present invention is a heat-shrinkable tube roll in which a long heat-shrinkable tube 1 having no ventilation parts such as cuts is flattened and wound, and the winding end 11 is sealed. This article relates to a characteristic heat-shrinkable tube roll.

The heat-shrinkable tube 1 of the present invention is obtained by stretching an original tube obtained by melt-extruding polyvinyl chloride, polyethylene terephthalate, etc. through an annular die in the radial direction using internal air pressure at a temperature above the softening point and below the melting point. It is a normal continuous-walled tube with no ventilation parts such as cuts. The stretched tube is then flattened with a nip roll and wound to obtain a heat-shrinkable tube roll.

In the heat-shrinkable tube 1 that has been wound, the winding end 1 becomes the only air intrusion path, so the winding end 11 is quickly sealed. Due to this,
Air is prevented from entering from the end portion 11, and waving and the like are significantly reduced. As for the sealing method, it is preferable to heat seal in the width direction and melt-bond, since it can be completely sealed, but it can also be easily sealed by simply bending.

(Example) Thickness 70μ, folded diameter (width of crushed tube)
16.5mm, radial shrinkage rate 45 when heated to 100℃
%, heat shrink tube 1 made of polyvinyl chloride, which also has an axial shrinkage rate of 10%, is attached to a core with a diameter of 124 mm.
It was rolled up for 200 m and cut into a heat-shrinkable tube roll with an outer diameter of 280 mm. Immediately after cutting, the end portion 11 of the winding was sealed in the width direction by heat sealing in Example 1, the end portion 11 was bent and sealed in Example 2, and the end portion 11 was left open after being cut in Example 1. Comparative Example 1. Place these in an electric enclosure at 30℃75%RH for 24 hours.
After being left for a period of time, evaluation was performed using the method described later, and as a result, the tendency shown in FIG. 3 was shown.

As is clear from Figure 3, in Comparative Example 1 as cut, the waving W was at most 5 mm as shown by curve C.
, and waving was observed up to a position 70 m back from the winding end 11. On the other hand, in Example 2, in which the end portion 11 was simply bent, the maximum waving W was 3.5 mm, as shown by curve b, and it was only observed up to a position 40 m back. As shown in Figure 2, the maximum undulation W is 2mm, and it is only recognized up to a position 30m back. Further, in Examples 1 and 2, there was less curvature than in Comparative Example 1, and unwinding could be easily performed.

Evaluation method for corrugation: As shown in Fig. 2, when the heat shrink tube 1 is placed on a flat table 2 cut to a length l = 1 m,
The maximum value mm of the undulation height W was measured and defined as the undulation W.

(Effects of the Invention) The heat-shrinkable tube roll of the present invention has an excellent effect in that since the wound end is sealed, air does not enter from there, and there is less undulation or curvature when unwinding.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing an example of the heat-shrinkable tube roll of the present invention, Fig. 2 is an explanatory diagram showing a method for measuring corrugation, and Fig. 3 is a horizontal axis from the end of the roll of the heat-shrinkable tube. It is a graph showing the relationship between the length L and the undulation W on the vertical axis. 1...Heat-shrinkable tube roll, 11... End of winding.

Claims (1)

[Scope of utility model registration request] A heat-shrinkable tube roll comprising a long heat-shrinkable tube 1 having no ventilation portions such as cuts, crushed flat, and rolled up, the end portion 11 of which is sealed.