JPH06158005A - Production of pressure-sensitive tape - Google Patents

Abstract

PURPOSE:To improve production efficiency, etc., in producing a pressure-sensitive tape by successively joining base sheets laminated with a thermoplastic resin in such a manner that the front end of each base sheet overlies the rear end of the preceding one, with the thermoplastic resin layer facing downward, and the overlaps are bonded by heating. CONSTITUTION:The front end of a base sheet 2 obtained by laminating a thermoplastic resin (e.g. polyethylene resin) to one side of a nonwoven fabric is sent to the lower side of the heater of a joining device 3, with the thermoplastic resin layer 22 facing downward. Simultaneously therewith, the rear end of a base sheet 1 is placed under the heater, with its thermoplastic resin layer 12 facing downward, so that the front end overlies the rear end over about 20mm. The overlap is bonded by hot-pressing with the heater. A release agent solution 41 is applied to the resulting continuous sheet on the thermoplastic resin layer side with a coater 4 and dried with a dryer 42. A pressure-sensitive adhesive 51 is then applied thereto on the other side 11 with a coater 5 and dried with a dryer 52. The coated continuous sheet is wound around a winder 6 to obtain a product 61.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an adhesive tape which joins base sheets of adhesive tape without using a splicing tape.

[0002]

2. Description of the Related Art Adhesive tapes having a thermoplastic resin layer such as polyethylene laminated on one side of a woven or non-woven fabric and an adhesive layer on the other side of the base sheet are widely used for packaging. Such a base material sheet is formed as a rolled body wound around a paper tube, and is unwound and applied with an adhesive on the exposed woven or non-woven fabric surface and dried, or an adhesive layer is laminated by a transfer method. Made with adhesive tape. Since the base material sheet is made into a wound body by winding a certain length,
When the base material sheet of one roll is lost in the manufacturing process, the end of the roll is joined to the start of the next new roll.

In the conventional joining method described above, the end portion and the starting end portion of the next new winding body are overlapped, and a splicing tape is stuck on the end portion and joined. The joining method using the above splicing tape is intended to continuously apply the adhesive without stopping the apparatus for replacing with the next roll of the new base sheet, and this method is used. After the adhesive is applied, the joint portion of is removed without becoming a product.

Therefore, even if the pressure-sensitive adhesive is continuously applied, the length of the base sheet of the original roll is equal to or shorter than the length of the base sheet. When manufactured, the last one will be a short product that is less than the standard size. For this short product, for example,
As described in Japanese Patent No. 669, it has been practiced that the ends of an adhesive tape provided with an adhesive layer are overlapped and bonded to each other to have a prescribed length.

[0005]

The joining method using the splicing tape requires the splicing tape. The part where the splicing tape is attached and joined is discarded as it is not used as a product and is discarded, and the base sheet becomes shorter than the original length, and the product is wound in a small size to meet the specified length. There are many short products. The method described in the above-mentioned publication for making this short product a prescribed length has a problem that the bonding strength is weak because the adhesive layer is simply laid on the back surface of the base material sheet, and is easily detached during use.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, does not require a splicing tape, has little waste of discarding a joint portion, and has a prescribed length. An object of the present invention is to provide a method for producing an adhesive tape that can produce an adhesive tape having less strength than a short product and having a large strength at a bonded portion.

According to the method for producing an adhesive tape of the present invention, in producing an adhesive tape comprising a thermoplastic resin layer laminated on one side of a woven or non-woven fabric and an adhesive layer provided on the other side of the base sheet, The end portion of one base material sheet and the end portion of the other base material sheet are overlapped so that the woven or non-woven fabric at the end portion of one base material sheet and the thermoplastic resin layer of the other base material sheet are in contact with each other. The thermoplastic resin layer of the other base material sheet is melted by heating and pressurizing the superposed part and impregnated into the woven fabric or the non-woven fabric at the end portion of the one base material sheet It is characterized in that the end portion is joined to the end portion of the other base material sheet, and then the adhesive layer is formed on the woven or non-woven fabric of the base material sheet thus joined.

The details of the present invention will be described below. Woven or non- woven fabrics As woven or non- woven fabrics, synthetic resin fibers such as polypropylene, polyethylene, polyester, nylon, cotton,
Natural fibers such as hemp and wool, or fibers obtained by blending and mixing these fibers are not particularly limited.

Thermoplastic resin layer This thermoplastic resin layer is originally a sealing layer for preventing the adhesive applied to the other surface of the woven or non-woven fabric from seeping out to the opposite surface. A release agent layer such as a silicone resin is formed on the surface of the plastic resin layer to facilitate the development of the pressure-sensitive adhesive tape as a roll. The present invention also utilizes this thermoplastic resin layer for melt bonding. As the thermoplastic resin layer, polyethylene, polypropylene, an ethylene-vinyl acetate copolymer or the like may be used as long as it can be heat-sealed, such as a mixture of two or more thereof, but polyethylene is particularly preferable.

The base sheet in which the thermoplastic resin layer is laminated on one surface of the woven or non-woven fabric is usually wound around a paper tube to form a rolled body. An adhesive layer is formed by applying an adhesive to one surface of the base sheet while unwinding the roll from the roll and then drying it, or by transferring an adhesive layer separately formed on the release paper surface. When the edge of the previous base sheet appears,
The woven or non-woven fabric at the end portion and the thermoplastic resin layer of the other base material sheet to be joined next are overlapped so as to be in contact with each other.
This superposition may be performed in the opposite manner to the above, in which the thermoplastic resin layer of the previous base material sheet is brought into contact with the woven or non-woven fabric of the other base material sheet to be subsequently bonded.

The superposed portion is heated and pressed, and the thermoplastic resin layer at this time may be on the upper side or the lower side. The heating and pressing may be performed from the surface of the thermoplastic resin layer of the overlapping portion, or may be performed from the surface of the woven fabric or the non-woven fabric. When heating from the surface of the thermoplastic resin layer, a film such as a fluororesin is interposed to prevent the molten resin from adhering to the heater. The heating and pressurizing method is not particularly limited, and examples thereof include a method of pressing a sheet-shaped electric heater against the overlapping portion with a cylinder, and a method of rolling while pressing an electric heating roller against the overlapping portion.

The heating temperature varies depending on the kind of the thermoplastic resin, but is preferably higher than the melting temperature of the thermoplastic resin. The pressurization needs a pressing force such that at least a part of the molten thermoplastic resin is impregnated between the fibers of the woven or non-woven fabric in contact with the thermoplastic resin. The time required for heating and pressing is appropriately selected depending on the heating temperature and the fiber density of the woven or non-woven fabric. After this heating and pressurization, when this portion is cooled, the thermoplastic resin of one base material sheet solidifies while being entangled with the fibers of the other base material sheet, so that a highly anchoring effect can be achieved.

A pressure-sensitive adhesive layer is formed on the exposed woven or non-woven surface of the base sheet joined as described above. The pressure-sensitive adhesive layer can be formed by directly applying a pressure-sensitive adhesive layer to a woven or non-woven fabric surface with a roll coater or the like, or by separately applying a pressure-sensitive adhesive agent on the release paper surface and then transferring and forming the pressure-sensitive adhesive layer. The method can be adopted.

[0014]

Since the woven or non-woven fabric at the end of one base sheet and the thermoplastic resin layer of the other base sheet are superposed on each other and the superposed portion is heated and pressed, one base sheet Since the thermoplastic resin layer is melted by heat and is impregnated between the fibers of the woven or non-woven fabric of the other base material sheet that is in contact with the thermoplastic resin layer, a joint having high joint strength can be obtained. In addition, the splicing tape can be joined without using it, and a waste portion unlike when using the splicing tape does not occur. Continuous operation is possible without stopping the production line.

[0015]

EXAMPLE (Example) FIG. 1 is an explanatory view showing an embodiment of the method of the present invention, in which a warp yarn of 30 count is used and 50 warp yarns / inch,
A base material sheet 1 obtained by laminating polyethylene resin with a thickness of 70 μm on one side of a woven fabric woven with 30 wefts / inch, with the polyethylene resin layer 12 facing down, is fed out, and a release agent liquid is applied by a release agent liquid coating device 4. 41 is applied to the polyethylene resin layer 12 side, the release agent liquid is dried by the dryer 42, and the adhesive 51 is applied by the adhesive coater 5 to the exposed woven fabric 11 side opposite to the polyethylene resin layer 12 side. Then, the pressure-sensitive adhesive is dried by the dryer 52, and wound into a small roll by the winder 6 to obtain the product 61.

FIG. 2 is an enlarged view of the splicing device 3 of FIG.
FIG. 3 is an enlarged side view showing an overlapping portion of the terminal end portion 13 of the base material sheet 1 and the starting end portion 23 of the base material sheet 2. When the end portion 13 of the base material sheet 1 approaches the splicing device 3, the next new base material sheet 2 having the same structure as the base material sheet 1 is supplied from the turret T to the splicing device 3 with the polyethylene resin layer 22 on the lower side. . 21 is a woven fabric of the base sheet 2. A fusion preventing film 35 made of fluororesin is provided on the upper surface of the frame 31.
A heater 32 having a width of 20 mm and having a length larger than the width of the base sheets 1 and 2 is vertically movable by a piston 33 of an air cylinder 34. It is supported.

The starting end portion 23 of the base sheet 2 is attached to the heater 32.
Under the heater 32 by pulling the upper surface of the base sheet 2 with the suction 36 and lifting it, and then the end portion 13 of the base sheet 1 is positioned below the heater 32 by the slide rolls R1 and R2. Therefore, the base material sheet 2 is separated from the suction 36, and as shown in FIG. 3, the starting end portion 23 of the base material sheet 2 is overlapped with the end portion 13 of the base material sheet 1 by 20 mm, and then the heater 32 is lowered to overlap it. Was heated and pressed at the temperature and heating time shown in Table 1. Pressing force is 3kg / cm ²
Is.

Woven fabrics 11 and 2 of the bonded base sheets 1 and 2
The adhesive tape obtained by applying an adhesive to one surface and drying it did not break at the joint even when used for packaging a corrugated cardboard box, and the joint was inconspicuous so that the position could not be known. Table 1 shows the results of examining the appearance and strength of the joint.

(Comparative Examples 1 and 2) Substrate sheets were joined in the same manner as in Examples except that the heating temperature was 200 ° C and the heating time was 5 seconds and 10 seconds. Table 1 shows the results of examining the appearance and strength of the joint.

[0020]

[Table 1]

[0021]

EFFECTS OF THE INVENTION Since the method of the present invention is constructed as described above, splicing tape is not required for joining the base material sheets, the amount of the adhesive tape to be discarded can be reduced, and the length of the adhesive tape is less than the specified length. It is also possible to reduce the production of goods. Further, since the thermoplastic resin layer of one base sheet is melted by heat and impregnated between the fibers of the woven or non-woven fabric of the other base sheet which is in contact with it, an adhesive tape having a high bonding strength can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining an example of a method for producing an adhesive tape of the present invention.

2 is an enlarged side view of the splicing device 3 of FIG. 1. FIG.

FIG. 3 is a cross-sectional view showing an overlapping portion of base material sheets.

[Explanation of symbols]

 1, 2: Base material sheet 3: Splicing device 11: Woven fabric 12: Polyethylene resin layer 13: Starting end portion 23: End portion 51: Adhesive

Claims (1)

[Claims] 1. An end portion of one base material sheet for producing a pressure-sensitive adhesive tape comprising a base material sheet in which a thermoplastic resin layer is laminated on one surface of a woven or non-woven fabric, and an adhesive layer is provided on the other surface of the base material sheet. The woven or non-woven fabric of No. 1 and the thermoplastic resin layer of the other base material sheet are in contact with each other, and one end of the base material sheet is overlapped with the end of the other base material sheet, and the overlapped portion is heated. The thermoplastic resin layer of the other base sheet is melted by applying pressure to impregnate the woven or non-woven fabric at the end of the one base sheet to impregnate one end of the base sheet and the other base sheet. A method for producing a pressure-sensitive adhesive tape, comprising the steps of: joining to an end portion of, and then forming a pressure-sensitive adhesive layer on the woven or non-woven fabric of the base material sheet thus joined.