JPS5976212A - Manufacture of thermally contractile tube - Google Patents

Abstract

PURPOSE:To continuously obtain a thermally contractile tube whose contraction ratio, thickness and length can be freely selected, by supplying a flat adhesive tape and a substrate tape onto a rotary shaft, and connecting this part of said wound tape to its preceding part to form the tube. CONSTITUTION:An adhesive tape B is continuously wound, and the front side of said adhesive tape B to be wound at the following time is connected to the rear side of the adhesive tape B wound at the preceding time. By pressing the connected parts with a press roll 11, an inner tube A comprising an adhesive layer is continuously formed on the periphery of a rotary shaft body 1. A substrate tape D after being sheeted is drawn, supplied along a helical direction onto the periphery of the inner tube A and continuously wound. At the same time, the front side of the substrate tape D to be wound at the following time is laid upon the rear side of the substrate tape D wound at the preceding time, and said lapping parts are pressed with a press roll 11' to form an outer tube C.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a heat-shrinkable tube from a flat base tape such as a thermoplastic resin or a rubber composition and a flat adhesive tape such as a hot-melt adhesive. More specifically, heat shrinkable tubes that have excellent adhesion to coverings and that allow for the continuous production of heat shrinkable tubes whose shrinkage rate, thickness, length, etc. can be freely selected according to the purpose of use. The present invention relates to a method for manufacturing a tube.

Conventionally, this type of heat-shrinkable tube has been manufactured by pressurizing a raw material tube extruded from an annular die of an extruder by injecting gas, liquid, or solid material into the tube at a temperature above the softening point and below the melting point. This method is used to expand the diameter and solidify by cooling, or to manufacture thick-walled heat-shrinkable tubes.The raw material tube is heated above the heat distortion temperature and one end of the cylindrical molded product is sealed, and then gas or liquid is Generally, a method has been adopted in which the material is press-fitted into the tube, expanded until it comes into close contact with the inner wall of the sizing vibe, and then cooled and solidified.

However, since all of the above methods are molded using an annular die, the diameter and wall thickness of the heat-shrinkable tube obtained are naturally limited to the shape of the die. Since dies must be prepared each time according to the type of product to be molded, this not only increases the manufacturing cost of the product but also complicates the manufacturing process, especially in the latter method, which requires continuous molding. As a result, manufacturing becomes extremely complicated, and the uses of the resulting products are also limited.Furthermore, pinholes that occur during molding impair waterproof and anticorrosive effects.

The present invention was invented in view of the above, and is a heat-shrinkable tube that can be continuously molded into a heat-shrinkable tube whose shrinkage rate, thickness, length, etc. can be freely selected depending on the purpose of use. The purpose of the present invention is to provide a manufacturing method, and while conventional heat shrinkable tubes have been manufactured using circular raw material tubes discharged from an annular die, the present invention provides a method for manufacturing heat shrinkable tubes using flat material tubes discharged from a flat die. An object of the present invention is to provide a method for manufacturing a heat shrinkable tube by supplying adhesive tape and base material tape to a rotating shaft body, and joining or weight joining the tapes as they are wound back and forth.

Embodiments of the present invention shown in the drawings will be described below, and its features will be explained in detail. FIG. This is a die for molding a flat adhesive tape B such as a hot-melt adhesive, which is rolled around the circumferential surface of the rotating shaft body 1 to mold an inner tube A made of an adhesive layer. A die is shown for molding a flat base tape D made of thermoplastic resin or rubber composition, which is wound around the circumferential surface of the rotating shaft body 1 to mold the outer tube C.

The rotating shaft body 1 shown here consists of a set of a plurality of rolls 1a, each of which is arranged in parallel along one virtual circumference so as to maintain a constant distance between adjacent rolls. One end of each shaft is rotatably supported by a base plate 3, and the other end is rotatably supported by a bearing plate 4 provided opposite to the base plate 3, so that the entire combination substantially constitutes one rotating shaft body 1. It's Nishide.

Further, in this embodiment, each of the rolls la is made into a hollow body, and the shaft 5 at one end thereof is also made into a hollow shaft to communicate with each other.
A water supply pipe 6 for cooling water is connected to each end of the shaft 5, and the other end of each roll 1a and the center shaft 7 are connected with a pipe material (not shown) to communicate the inside. Cooling water pumped through the water pipe 6 is supplied to each roll 1a to cool it, and at the same time, the sent cooling water is collected in the hollow part of the central shaft 7 through the pipe material and drained from the end of the central shaft 7. This allows the rotating shaft body 1 to be internally cooled.

Further, each roll 1a rotates a bearing plate 4 in one direction by a required angle with respect to the substrate 3, and one end of each roll 1a that is supported on the substrate 3 is supported on the bearing plate 4, and the bearing plate 4 on the other end is By shifting the rolls 1a, that is, by twisting and tilting each roll 1a about the center line of the rotating shaft 1, the tape B wound on the rotating shaft 1 is wound in a spiral shape.

A sprocket (not shown) is provided at the shaft end of each roll 1a on the substrate 3 side, and each roll 1a is rotated in the same direction at a constant speed by the operation of a chain (not shown) attached to the sprocket. Substantially, the circumferential surface of the rotating shaft body 1 rotates.

A flat adhesive tape B made of hot-melt adhesive or the like discharged from the die 2 of an extruder is supplied to the rotating shaft body 1 configured in this manner along the circumferential surface of the rotary shaft body 1 in a spiral direction. .

Next, the adhesive tape B was continuously wound, and at the same time, the leading edge side of the adhesive tape B that was wound later was joined to the trailing edge side of the adhesive tape B that was wound earlier. By pressing the parts together with a pressure roll 11, an inner tube A made of an adhesive layer is continuously formed on the circumferential surface of the rotary shaft body 1.

Next, the flat base tape D made of thermoplastic resin, rubber composition, etc. discharged from the die 2° of the extruder is once sheeted and then stretched, and is rolled onto the circumferential surface of the inner tube A along the spiral direction. Supplied.

Immediately, this flat base tape D is discharged from the die 2° of the extruder, and while being wound onto the inner tube A on the rotating shaft 1, it is formed by the sheeting roll 8, and then stretched. After being maintained at a required temperature, the tape is stretched 2 to 8 times in the machine direction by adjusting the speed ratio between the rolls of the stretching rolls 9 to form the base tape D.

The reason why the draw ratio of the base tape D is set to 2 to 8 times is that if the draw ratio is less than 2 times, a heat-shrinkable tube with the desired shrinkage ratio cannot be obtained, whereas if it is 8 times or more, the However, it is difficult to stretch and has poor formability.

Next, the base tape D is heated to the optimum temperature for fusion using a preheat roll 10 or the like, and is supplied onto the inner tube A wound around the circumferential surface of the rotating shaft body 1 while being taken off, and is continuously wound. At the same time, the front edge side of the base tape D to be wound backward is overlapped with at least the upper surface of the rear edge side of the base tape D wound earlier, and this overlapping part is pressed with a pressure roll 11. By forming the outer tube C, the rotating shaft body 1
A tube body having an adhesive layer on the inner circumferential surface is continuously molded on the circumferential surface of the tube, and is taken off while being cooled.

As for the molecular orientation of the base tape D, as shown in FIG. 2, instead of the above-mentioned stretching process, it may be carried out by applying a predetermined draft rate and drawing it down. In this case, a draft rate of 200 to 1000% is applied while being discharged from the die 2 and wound onto the inner tube A on the rotating shaft body 1.
oriented longitudinally. Here, the draft rate is 20
The reason why it is set as 0 to 1000% is that if it is 200% or less, a heat-shrinkable tube with the desired shrinkage rate will be obtained, whereas if it is 1000% or more, the base tape D will break during drafting, etc. Poor moldability.

The present invention has been described above with reference to embodiments, but as is clear from the above, the present invention applies a flat adhesive tape such as a heat-meltable bot-melt adhesive discharged from a die of an extruder onto a rotating shaft. A portion that is joined by supplying it along the helical direction and turning it continuously tS, and at the same time joining the leading edge side of the adhesive tape that is wound later to the trailing edge side of the adhesive tape that was wound earlier. An inner tube made of an adhesive layer is continuously molded on the circumferential surface of the rotating shaft by pressing it with a pressure roll, and the thermoplastic resin or rubber composition that is heated and melted is discharged from the die of another extruder. A flat base material tape for objects, etc. is drawn down at a predetermined draft rate, or once it is sheeted, it is stretched at a predetermined magnification in the flow direction depending on the speed ratio between the rolls, and then it is first drawn onto the rotating shaft. At the same time, the leading edge side of the base tape to be wound later is overlapped with at least the upper surface of the trailing edge side of the base tape wound earlier. At the same time, the overlapping portions are pressed together using a pressure roll to form an outer tube, and a tube body having an adhesive layer on the inner circumferential surface is continuously formed on the circumferential surface of the rotating shaft body. Since shrinkable tubes are manufactured, the thickness and length of the tube can be freely selected depending on the purpose of use.Therefore, the length of the tube is not limited as in the past, and the die can be changed according to the diameter and wall thickness. There is no need to make any selections, and the shrinkage rate is selected by the stretching ratio or draft rate applied to the flat tape, which greatly improves moldability, eliminating the disadvantages of limited use and high cost of conventional products. Furthermore, by layering an adhesive layer on the inner circumferential surface of the tube, it not only improves bonding with the coating, but also seals pinholes caused by molding, making it waterproof and corrosion-proof. The effects can also be improved.

The present invention will be described below with reference to Examples, but the present invention is not necessarily limited to these Examples.

Example 1 A flat adhesive tape such as a hot-melt adhesive that can be heated and melted is discharged from an extruder die having a diameter of 45 mm in width and 0.6 mm in thickness, and is placed on a rotating shaft along a spiral direction. At the same time, the leading edge side of the adhesive tape to be wound later is joined to the trailing edge side of the adhesive tape that was wound earlier, and the joined part is placed on a pressure roll. By crimping the inner tube with an adhesive layer on the circumferential surface of the rotating shaft body, an inner tube with a width of 120 mm is formed.
It is discharged from an extruder die with a diameter of 1.15 mm in thickness, and is applied to a sheeted flat polyvinyl chloride base tape with a stretching roll at a temperature of 110°C to give a 2.0 to 6.0 times the strength. After being stretched, the adhesive tape is supplied along the spiral direction onto the above-mentioned adhesive tape that is wound on the rotating shaft body, and is continuously wound, and at the same time, from behind the upper surface of at least the trailing edge side of the previously wound tape is supplied. The front edges of the wound tapes were overlapped and the overlapping portion was cooled while being pressed with a pressure roll to obtain a heat-shrinkable tube having an adhesive layer on the inner peripheral surface as shown in Table 1.

Example 2 A flat adhesive tape such as a hot-melt adhesive that can be heated and melted is discharged from an extruder die having a diameter of 45 mm in width and 0.6 mm in thickness, and is placed on a rotating shaft along a spiral direction. At the same time, the leading edge side of the adhesive tape to be wound later is joined to the trailing edge side of the adhesive tape that was wound earlier, and the joined part is placed on a pressure roll. By crimping the inner tube with an adhesive layer on the circumferential surface of the rotating shaft body, an inner tube with a width of 54 m is formed.
A polyvinyl chloride base tape with a resin temperature of 160°C discharged from an extruder die having a diameter of 1.15 mm in thickness was oriented while applying a draft rate of 182 to LO94%, and the obtained base The material tape is supplied along the helical direction onto the adhesive tape wound on the rotating shaft body, and at the same time as it is continuously wound, it is applied from behind to at least the upper surface of the trailing edge side of the previously wound tape. The front edges of the wound tapes were overlapped, and the overlapping portion was cooled while being pressed with a pressure roll to obtain a heat-shrinkable tube having an adhesive layer on the inner peripheral surface as shown in Table 2.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIGS. 1 and 2 are explanatory perspective views showing the tape supply state, and FIGS. 3 and 4 show the manufactured shrink tube along the axial direction. FIG.

Claims (1)

[Claims] +1) A flat adhesive tape such as a hot-melt adhesive that can be heated and melted discharged from a die of an extruder is supplied onto a rotating shaft along a spiral direction and continuously wound. At the same time, the leading edge side of the adhesive tape wound later is joined to the trailing edge side of the adhesive tape wound earlier, and the joined part is pressed with a pressure roll, thereby forming the rotating shaft body. An inner tube consisting of an adhesive layer is continuously molded on the circumferential surface, and a flat base material tape made of heat-melting pJ f4 Ti resin or rubber composition discharged from the die of another extruder is placed in a predetermined shape. The adhesive tape is drawn down by multiplying the draft rate, or after it is once sheeted, it is stretched at a predetermined magnification in the flow direction depending on the speed ratio between the rolls, and then it is continuously supplied onto the adhesive tape that has been previously wound on the rotating shaft. At the same time, the leading edge side of the base tape to be wound later is overlapped with at least the upper surface of the trailing edge side of the base tape previously wound, and this overlapping part is pressed with a pressure roll. A method for producing a heat-shrinkable tube, comprising the steps of: forming an outer tube to continuously mold a tube body having an adhesive layer on the inner circumferential surface on the circumferential surface of a rotating shaft body; (2) The draft rate of the base tape is 200 to 1000
%. The method for manufacturing a heat-shrinkable tube according to claim 1. (3) The method for producing a heat-shrinkable tube according to claim 1, wherein the stretching ratio of the base tape is 2 to 8 times.