JP3754904B2 - Thermal welding method for cylindrical plastic sheet materials - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention particularly relates to a thermal welding method for thermally welding a plastic sheet material formed in a cylindrical shape to another plastic sheet material.
[0002]
[Prior art]
In the processing of conventional pneumatic vinyl dolls, when the arm is attached to the torso and the head is attached to the torso, the “ring winding” method is used.
[0003]
As shown in FIG. 8A, the “ring winding” processing method inserts a cylindrical vinyl chloride sheet a1 inside a cylindrical metal heating jig 7 and heats its tip 10 for heating. The end of the jig 7 is fixed by wrapping around the outer surface, and is brought into contact with another polyvinyl chloride sheet a2, and then the tip of the heating jig 7 is heated by high frequency, ultrasonic waves, etc. The portion 10 is welded to the other plastic sheet a2.
[0004]
[Problems to be solved by the invention]
However, such a “ring winding” welding method has a problem that the welded portion by the overhanging portion 10 is exposed to the outside of the cylindrical portion of the PVC sheet, and the appearance is damaged, as shown in FIG. If the hole 11 is formed in the hole 10, even if it is small, the welded portion 10 is located outside the cylindrical portion, so that the air inside the hole 11 leaks as it is and is often punctured. Therefore, there is a production problem that the defective rate of the product becomes high.
[0005]
In addition, due to environmental problems such as dioxin, which has been regarded as a problem in recent years, vinyl chloride, which has been conventionally used for empty vinyl dolls, has been avoided. However, vinyl chloride is excellent in ductility, and there was no problem in “ring winding” processing. However, there are materials with poor ductility among alternative PVC materials, and “ring winding” is difficult. If this is the case, with a material with poor ductility, as a result, “ring winding” takes time and labor to wrap it outward, which is more time consuming and labor intensive, and is more costly to manufacture than vinyl chloride products. There was a problem that it would be expensive.
[0006]
The present invention solves the above-mentioned problems, and particularly has a good appearance, and the welded portion is on the inside, so even if some holes are opened during welding, the internal plastic sheet does not leak outside It is an object of the present invention to provide a method for thermally welding materials.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, a method for thermally welding a cylindrical plastic sheet material according to the present invention is a member that has a hole that communicates with a cylindrical plastic sheet and is filled with air. Is a method of welding to another plastic sheet material constituting the above , characterized by having the following requirements.
(B) The end portion on the welding side of the cylindrical plastic sheet material is disposed on the hole of the other plastic sheet.
(B) Inserting the cylindrical heating jig of the heat welding machine inside the cylindrical plastic sheet material
(C) The end portion on the welding side of the cylindrical plastic sheet material is bent toward the inside of the heating jig, and in this state, the heating jig is welded together with the end portion on the welding side. Abutting on a plastic sheet material and heat welding.
In addition, it is preferable that the cylindrical plastic sheet material is formed with a small diameter in the vicinity of the end portion on the welding side.
[0009]
Further, the cylindrical plastic sheet material may be a multilayer plastic sheet material in which a heat welding material is disposed in an intermediate layer.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of a pneumatic doll manufactured by a heat welding method according to the present invention. Reference numeral 1 denotes a body part, 2 denotes a head part, 3 denotes an arm part, and 4 denotes a foot part.
[0011]
The doll is made of PP (polypropylene), and the head portion 2, the arm portion 3, and the foot portion 4 are bonded to the body portion 1 by heat welding.
[0012]
Next, a method for thermally welding the arm 3 to the body 1 by high frequency welding will be described.
[0013]
The body part 1 and the arm part 3 are each formed by superposing and heat-sealing two PP sheet materials a, but as shown in FIG. 3a and the end portion 3b on the base side are not sealed. Thereby, it forms in the cylinder shape from the intermediate part 3a of the arm part 3 to the edge part 3b. Further, the end 3b is squeezed so as to have a small diameter toward the end. When using a material excellent in ductility, it is not always necessary to squeeze the end portion.
[0014]
A hole 5 is formed in the arm portion corresponding portion of the body portion 1.
[0015]
Next, as shown in FIGS. 3 and 4, a cylindrical heating jig 7 of a high-frequency heat welding machine (not shown) is inserted from the open portion 6 in the middle of the arm portion. At this time, since the end 3b of the arm 3 has a small diameter, it is bent inward of the heating jig 7.
[0016]
In this state, as shown in FIG. 5, the heating jig 7 is brought into contact with the plastic sheet material a of the body portion 1 to be welded together with the end portion 3b on the welding side. When the heat welding machine is operated to generate a high frequency from the heating jig 7, the plastic sheet material a and the end 3b that are in contact with each other are heated, and the end 3b of the arm 3 is the body part. 1 is bonded by heat welding.
[0017]
Thereafter, the heating jig 7 is extracted from the opening 6 of the arm 3 and the two sheet materials a of the opening 6 of the arm 3 are heat-sealed, whereby the arm 3 is completed. Accordingly, when air (other gas may be used) is blown from the body portion 1, the air is further blown into the arm portion 3 through the hole 5 corresponding to the arm portion as shown in FIG. 6 to expand as shown in FIG. .
[0018]
The plastic sheet material a may have a single-layer structure as described above. However, as shown in FIG. 7, a thin film material or sheet material a1, a2 of PP (polypropylene) or PE (polyethylene) is used. It is preferable to use a plastic sheet material having a multilayer structure in which a film material or sheet material a3 made of EVA resin having excellent heat weldability is sandwiched between the intermediate layers. EVA resin alone has good heat-weldability (low melting point) and good compatibility with PP and PE. Therefore, it is possible to improve heat-weld and promote adhesion and secure strength.
[0019]
By adopting a multilayer structure, the characteristics of the material constituting each layer can be utilized, so that various characteristics can be provided as compared with a single-layer structure. For example, it is possible to change the heat weldability, ductility, elasticity, strength, heat / cold resistance, gas barrier properties, and the like.
[0020]
As materials that can be used for the plastic sheet material described above, olefinic, polyamide-based, styrene-based, and vinyl acetate-based materials are mainly suitable. Also good.
[0021]
The same may be done when the body 1 and the head 2 are welded.
[0022]
As described above, since the end portion 3b to which the plastic sheet material is welded is bent inward of the cylindrical portion, the welded portion cannot be seen from the outside. Therefore, unlike the conventional “ring winding”, the welded portion of the plastic sheet material is not exposed and the appearance is not impaired.
[0023]
Also, even if a hole 8 that allows air to leak into the welded portion 3b at the time of welding is located inside the cylindrical portion, the possibility of air leaking out is very small as long as it is sealed. . Therefore, the defective rate of the product is lowered and the production efficiency is improved.
[0024]
In addition, as for the said cylindrical plastic sheet material, as FIG.3 and FIG.4 shows, it is preferable to make it form a small diameter near the edge part by the side of welding. According to this, even if it is a material with poor ductility like a polypropylene, since the bending to the inward of the heating jig | tool 7 is performed naturally, it can weld reliably.
[0025]
Furthermore, the above-mentioned heat welding method may be applied not only to heat welding using high frequency but also to welding using ultrasonic waves, and can also be applied to heat sealing that directly heats.
[0026]
【The invention's effect】
According to the invention according to claim 1, the cylindrical heating jig of the thermal welding machine is inserted inside the cylindrical plastic sheet material, and the end portion on the welding side of the cylindrical plastic sheet material is The heating jig is bent toward the inside, and in this state, the heating jig is brought into contact with another plastic sheet material to be welded, and heat welding is performed. Therefore, the welded portion is not visible from the outside, so the appearance is good.
[0027]
In addition, even if a small hole is opened or damaged that causes air to leak into a part of the weld during welding, it is located inside the cylindrical part of the plastic sheet material, so air can leak out. Sex is very small. Therefore, the defective rate of the product is lowered and the production efficiency is improved.
[0028]
Furthermore, since the above-mentioned heat welding method can be performed using a conventional “ring winding” processing machine as it is, no equipment cost is required.
[0029]
When the above-mentioned heat welding method is applied to a vinyl chloride material, not only can the work speed be improved, but also small diameters can be easily processed.
[0030]
According to the invention according to claim 2, since the vicinity of the end portion on the welding side is formed to have a small diameter toward the end portion, even a material having poor ductility such as polypropylene may be inward of the heating jig. Since the bending is naturally performed, welding can be surely performed. Therefore, it is possible to avoid the risk of providing products using the PVC-free material.
[0031]
According to the third aspect of the invention, the strength and gas barrier properties are superior to those of the single-layer structure. Therefore, once air is introduced, the expanded state is maintained for a long time, and the predetermined shape is maintained. Even if it receives rough handling, it is hard to be damaged.
[Brief description of the drawings]
FIG. 1 is a perspective view of a pneumatic doll manufactured by a heat welding method according to the present invention. FIG. 2 is a perspective view of a part of an arm part and a body part. FIG. 3 is a state in which a heating jig is put in the arm part. FIG. 4 is a cross-sectional view showing a state where a heating jig is put in the arm portion. FIG. 5 is a cross-sectional view showing a heat welding mode. FIG. 6 is a cross-sectional view showing a state where heat welding is completed. Partial enlarged cross-sectional view of sheet material [Fig. 8] (a) and (b) are explanatory diagrams of welding by conventional "ring winding"
1 Body 3 Arm 3b End 7 Heating Jig

Claims (3)

A method of welding a plastic sheet material formed into a cylindrical shape to another plastic sheet material that has a hole communicating with the cylindrical plastic sheet and constitutes a member to be filled with air, and has the following requirements: A thermal welding method for plastic sheet material, characterized by
(B) The end portion on the welding side of the cylindrical plastic sheet material is disposed on the hole of the other plastic sheet.
(B) Inserting the cylindrical heating jig of the heat welding machine inside the cylindrical plastic sheet material
(C) The end portion on the welding side of the cylindrical plastic sheet material is bent toward the inside of the heating jig, and in this state, the heating jig is welded together with the end portion on the welding side. Contact with plastic sheet and heat weld   The method for heat welding a plastic sheet material according to claim 1, wherein the cylindrical plastic sheet material is formed with a small diameter in the vicinity of the end portion on the welding side. The method for heat welding a plastic sheet material according to claim 1 or 2, wherein the cylindrical plastic sheet material is a multilayer plastic sheet material in which a heat welding material is disposed in an intermediate layer.

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