JP2002046185A - Plastic material welding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plastic material welding method capable of rapidly and certainly performing welding work to enable strong welding, eliminating necessity for drawing a welding material from a plastic material even after welding to treat the same, low in cost, requiring no labor and considering environment. SOLUTION: A plurality of substantially untwisted fiber bundles comprising carbon fiber filaments are intertwisted to form a welding material, and a groove having depth less than 1/2 of the apparent diameter of the welding material is provided to the surface of one of both plastic materials to be welded having at least smooth welding surfaces continuing over the whole thereof from a current inlet to reach a current outlet. After the welding material is continuously arranged in the groove, temporary fastening spots are formed to a plurality of proper places of the welding material and, subsequently, the welding surface of one plastic material is superposed on the other plastic material to be brought into contact therewith under pressure and, in this state, a current is passed through the end part of the welding material to heat the fiber bundles to mutually weld the plastic materials to be welded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for welding plastic materials mainly having thermoplasticity by heat.

[0002]

2. Description of the Related Art Conventionally, fusion of plastic materials mainly composed of thermoplastic materials by heat (hereinafter referred to as "welding") has been known.
Although it is performed in various places, for example, in the case of door parts of automobiles, body parts of audio equipment, water purifiers, etc. Was being done. In this conventional welding method of heat between plastic materials mainly composed of thermoplastics, a same-shaped groove having a width of, for example, 1.0 to 2.0 mm is dug in each of welding surfaces of a pair of welding plastic materials to be welded. A nichrome wire pre-molded in accordance with each groove is embedded, a pair of welded plastic materials is crimped with a nichrome wire interposed between the grooves, and then a current-carrying device is conducted to both ends of the nichrome wire, and a current is supplied to the current-carrying device. When the control is performed, a method has been used in which the nichrome wire is heated by energization and the welded plastic materials are melted and welded at the groove.
In addition, in the case of olefin resins such as polyethylene and polypropylene, the welding force by the energization of a nichrome wire is insufficient, and in this case, the bonding is performed using a chemical adhesive.

[0003]

According to the above prior art, the nichrome wire as the welding material remains as it is even after the welding plastic materials are welded by heat. In recent years, manufacturers have been required to separate metals and plastics from the viewpoint of recycling plastics. Therefore, a great deal of labor has been required to pull out and separate Nichrome wires from a molded product of welded plastic. In the case of bonding with an olefin-based resin using a chemical adhesive, the workability is poor, the adhesive strength is not sufficient, and harmful substances may be eluted in applications such as water purifiers, so that use thereof has been limited. The present invention overcomes these problems, enables the welding operation to be performed quickly and reliably, enables strong welding between a wide range of thermoplastic resins, and requires that the welding material be pulled out of the welding plastic material and processed after welding. It is an object of the present invention to obtain a plastic material welding method which is low in cost, requires no labor and is environmentally friendly.

[0004]

In order to achieve this object, according to the invention of claim 1, a plurality of substantially non-twisted fiber bundles composed of carbon fiber filaments are twisted to form a welding material. A groove having a depth shallower than 1/2 of the apparent diameter of the welded material which reaches the current outlet continuously from the current inlet to the whole surface of the one or other welded plastic material having at least a smooth welded surface. After the welding material is continuously arranged in the groove, temporary fixing spots are formed at a plurality of appropriate places of the welding material, and then the other welding surface of the welding plastic material is overlapped with the other welding surface while being pressed. The problem has been solved by a plastic material welding method in which a current is applied to an end of the welded material and the welded plastic materials are welded to each other by heating the fiber bundle. In the invention of claim 2,
The fiber bundle in which the welding material is substantially untwisted is impregnated with a cellulosic adhesive or a thermoplastic resin adhesive and dried to twist a plurality of yarns having a resin coating formed on at least the surface of the fiber bundle. It is preferable to use the method for welding a plastic material according to claim 1 which is formed by heating. In the invention of claim 3, the welding material is obtained by twisting a plurality of fiber bundles in a substantially non-twisted state, then impregnating with a cellulosic adhesive or a thermoplastic resin adhesive, and drying the fiber bundle. It is preferable to adopt the method for welding a plastic material according to claim 1, wherein a resin film is formed on a surface portion. According to the invention of claim 4, the twisting of the fiber bundle or the yarn is 20 times in the number of twists per meter and the twist coefficient calculated by the tex number.
It is preferable to use the plastic material welding method according to any one of claims 1 to 3, which is set to 00 to 5500. In the invention according to claim 5, it is preferable to adopt the method for welding plastic material according to any one of claims 1 to 4, wherein the cross-sectional shape of the groove is substantially symmetrical and concave downward. Claim 6
According to the invention, a scribe line extending continuously from the current inlet to the current outlet is provided in place of the groove provided on one surface of the welding plastic material, and the welding material is continuously arranged along the scribe line. The method for welding a plastic material according to any one of claims 1 to 4 may be provided. According to a seventh aspect of the present invention, in the method for welding a plastic material according to the sixth aspect, the method for welding a plastic material may include forming a plurality of sawtooth-shaped narrow grooves intersecting with the score line.

In the invention according to claim 8, the temporary fixing spot is formed by welding in which the welding material is locally heated by a spot-shaped heating element. can do. Claim 9
In the above invention, the temporary fixing spot is formed by bonding in which a small amount of a cellulose or thermoplastic resin adhesive is locally injected into a welding material by an injector. Can be a method. According to the tenth aspect of the present invention, instead of forming the temporary fixing spot, the plate-shaped main body member in which the slit having the upper opening is formed is provided at one of the grooves or the scored line of the welded plastic material. The welding member is pushed into the slit so as to protrude, and the main body member is fitted into the fitting groove by overlapping one of the welding plastic material with the other of the welding plastic material having a fitting groove formed in the lower surface. Item 7. A method for welding a plastic material according to any one of Items 1 to 7. According to the eleventh aspect of the present invention, one and the other of the welded plastics made of the base material that intersects in a substantially L-shape are used, and a linear groove provided on the upper end surface of each base material of the one of the welded plastics is A corner groove that is deeper than the arc-shaped groove when viewed from the front is formed at the intersection corner continuously with the groove, and the groove is formed from a current inlet at one end of one groove of the welded plastic material via the corner groove. A welding material is disposed continuously to the current outlet at the other end, and the other of the welded plastic materials provided with a corner projection to be loosely fitted corresponding to the corner groove is pressure-bonded to one side. The plastic material welding method according to any one of claims 1 to 5, wherein the welding plastic materials are welded to each other by energizing and heating the ends of the welding material while heating. According to the invention of claim 12, substantially L
Using one and the other of the welded plastic material consisting of the base material intersecting in the shape of a letter, a linear groove is provided to intersect the upper end surface of each base material of one of the welded plastic materials, and the one of the intersecting base materials is provided. A welding material is continuously disposed from a current inlet at one end of the groove to a current outlet at the other end of the groove, and a current outlet at the other end of the groove from the current inlet at the other end of the groove intersecting the base material. The welding material is disposed continuously until the other end of the welding plastic material is overlapped on one side and pressurized while first applying heat to the end of the welding material on one side of the base material, and then the other side of the base material The method of welding a plastic material according to any one of claims 1 to 5, wherein the welded plastic materials are welded to each other by energizing and heating the end of the welded material.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a method for welding a plastic material (hereinafter simply referred to as a welding method) according to the present invention will be described in detail in the following order with reference to the drawings. Figure 1
FIG. 2 is a schematic view schematically showing a part of an example of a welding material used in the welding method of the present invention. FIG. 2 is a schematic perspective view and a cross-sectional view of an example of a welding plastic material used in the welding method of the present invention and a preparation process of another example. FIG. 3 is an explanatory diagram of an example of a temporarily fixing step of the welding material in the welding method of the present invention. FIG. 4 is an explanatory view of another example of the temporary fixing step of the welding material in the welding method of the present invention. FIG. 5 is a schematic explanatory view of an example of the welding method according to the present invention, and is a left side view, a plan view, and a right side view of a welding material and a welding plastic material in each step, respectively. Welding material setting process,
The (c) welding material temporary fixing step and the (d) welding step are shown. FIG.
FIG. 4 is a schematic explanatory view of one example and another example at the intersection corner of the welding method of the present invention. In each of the drawings, the same components are omitted from description or the same reference numerals are assigned, and detailed description is omitted.

First, an example of a welding material used in the welding method of the present invention will be described with reference to FIG. The welding material 1 is obtained by twisting a plurality of yarns 11 each having a resin film 11b formed at least on the surface thereof on a carbon fiber filament fiber bundle 11a (two in this example), and has a substantially circular cross section with an apparent diameter d. . Here, the apparent diameter d is obtained by approximately selecting the circumcircle of each of the constituent yarns 11. The fiber bundle 11a used for one yarn 11 generally has a carbon fiber filament of one.
2,000 to 12,000 bundles with a thickness of 0.2 to 1.5 mm,
This is a case in which no special twisting treatment has been performed and there is only a slight twist of, for example, about 10 or less per meter so as to be easily twisted or bundled, that is, in a substantially untwisted state. The resin coating 11b is prepared and set as follows.
It is possible to temporarily fix any part of the welding material 1 by local welding, so that the work in the temporary fixing step can be easily performed. In order to obtain the resin film 11b in one yarn 11, a cellulose-based or thermoplastic resin adhesive is used. In the case of the cellulose-based adhesive, in the acetone solution, in the case of the thermoplastic resin adhesive, Is impregnated by immersing the fiber bundle 11a in a water-soluble emulsion solution, squeezed by a dice or a squeezing roller, and then dried to form a resin film 11b on at least the surface. The finished form of the yarn after the resin impregnation is wound in a relatively soft strand state, and a plurality of strands are twisted to obtain the welding material 1. The thickness of the resin film 11b is 0.0
It is preferable that the thickness is in the range of 1 mm to 0.08 mm. If the thickness is larger than 1 mm, the welding material 1 becomes rigid and hard to bend, and the heating by energization is hindered, and the welding force is weakened. May remain and the workability may deteriorate. Further, the raw yarn 11 obtained by drawing and twisting a plurality of unprocessed fiber bundles 11a before the resin coating 11b is formed is formed into a resin coating 11b with a cellulose-based or thermoplastic resin adhesive by the method described above. The welding material 1 can be obtained, but from the viewpoint of uniform resin impregnation, the welding material 1 in which a plurality of the raw yarns 11 processed by the resin are aligned and twisted as described above is preferable. Furthermore, the raw yarn 11 of the welding material 1 is
The unprocessed fiber bundle 11a without the resin film 11b formed thereon can be used as long as a plurality of strands are simply twisted, provided that strong twisting for suppressing loosening, fluffing, bending, and the like is performed. . However, in this case, the temporary fixing may be performed by local welding, but the welding force of the temporary fixing may be insufficient. Therefore, it is more preferable and more preferable to perform the temporary fixing by bonding or engaging with a locking tool, which will be described later. In each case,
The reason why the welding material 1 has a plurality of raw yarns 11 or fiber bundles 11a twisted is that air in the fiber bundles 11a is expelled as much as possible to form a high-density heating element to increase the efficiency of heat generation by energization.
This is because it is effective to improve the workability in the preparation, setting, and temporary fixing steps by minimizing unraveling, fluffing, bending, etc., and to improve the welding force. Twisting is preferably performed with a relatively strong twist of usually about 2000 to 5500 in terms of a twist coefficient calculated by the number of twists (per meter) and the count (tex). If the number of twists is too large, the cost increases, and usually two or three strands are used, and two strands are most frequently used. Here, if a plurality of single yarns that are not twisted are used, they are in a bulk state, and the welding force is insufficient due to the presence of internal air. In particular, the bent portions are easily peeled off, and the workability in the setting process is low, which is not suitable. Examples of the cellulose-based adhesive for the resin film include those using nitrocellulose as a main raw material, and examples of the thermoplastic resin adhesive include those using vinyl acetate, PVA, or the like as a main raw material. As a kind of plastic material that can be welded, a plastic material mainly composed of a thermoplastic resin is used, for example, polyvinyl chloride, polyester, polyacryl, polyamide, polystyrene, polycarbonate,
There are non-olefins such as ABS or polyethylene terephthalate and olefins such as polyethylene and polypropylene.

As sequentially described below, the welding method of the present invention includes a preparation step, a welding material setting step, a welding material temporary fixing step, and a welding step. First, first and second examples of the welding method of the present invention will be described with reference to FIGS. In FIGS. 3 and 5, the plan views are up, down, left, and right as viewed from the front. First, a first example of the welding method of the present invention will be described. 2 (a) and FIG. 5 (a), one welded plastic material 2 is entirely formed on a plate-shaped thermoplastic plastic base material 21 and a smooth surface of the base material 21 to be welded. A narrow groove 22 having an arcuate cross-section is formed continuously. The groove 22 has a straight portion 22a and a current inlet 22.
c and a current outlet 22d and, if necessary, a bent portion 22b, the shape of a plastic material to be welded to them,
In accordance with the size, the desired welding force, etc., each is arranged in combination to form a welding pattern, starting from the current inlet 22c and continuously formed over the entire surface of the substrate 21 and ending at the current outlet 22d. Have been. The current inlet 22c and the current outlet 22d are open at the ends of the base member 21 and can be connected to each other. However, the positions may be interchanged. It is more convenient to be in a close position for energization by. Here, the bent portion 22b is not limited to the bent in the illustrated right-angle direction, and may be an acute angle, an obtuse angle, an arc shape, or another curved shape. The cross-sectional shape of the groove 22 is usually formed in a symmetrical downwardly concave circular arc or other curved shape, and the depth h of the groove 22 is one of the apparent diameter d of the welding material 1 to be used as described later.
/ 2, the width w of the surface is the apparent diameter d of the welding material 1.
It is slightly larger. When the ends of the current inlet 22c and the current outlet 22d communicate with the through-holes 32 described later, the current inlet 22c and the current outlet 22d do not necessarily have to be opened at the ends of the base material 21. On the other hand, the separately welded plastic material 3 to be superimposed on the welded plastic material 2 shown in FIG. 2 (a) is a plate-like heat having the same shape and the same kind as the base material 21 to be welded in plan view. When the base material 31 made of a thermoplastic plastic and the welded plastic material 2 are overlapped, the groove 2 is formed.
Two current inlets 22c and 22d are provided with a pair of vertically penetrating through holes 32 having a diameter of several millimeters in the vertical direction and capable of communicating near terminals. The welding material setting step is shown in FIG.
In FIG. 5B, the welding material 1 is disposed along the groove 22 of the one welding plastic material 2 described with reference to FIG. The welding material 1 is provided with a combination of a straight portion 1a, a bent portion 1b, a current inlet 1c, and a current outlet 1d corresponding to the groove 22, and the current inlet 1c and the current outlet 1d are laid outward from the substrate 21. Do not protrude or the terminal is slightly protruding. When the welding material 1 is set, the welding material 1
FIG. 2 shows the groove 22 on the surface of the welded plastic material 2.
(A) As shown in ac), the upper part of which is more than 1/2 of the apparent diameter d is exposed. The welding material 1 has an appropriate plasticity due to the twist of the raw yarn 11 and the resin coating 11b on the surface thereof, and the dispersing, fluffing, bending, and the like are suppressed. And it can be performed reliably. However, in this state, when vibration, tension, or the like is applied, the linear portion 1a and the bent portion 1b are likely to come off from the groove 22, so that the next welding material temporary fixing step is required.

In the welding material temporary fixing step, in 5 (c),
For the sake of clarity, a description will be given also with reference to FIG. A plurality of spots indicated by solid circles of the welding material 1 disposed along the grooves 22 are pressed from above by a spot-shaped heating element having a sharp tip to locally heat the resin material of the resin film 11b of the welding material 1. To melt the groove 2
The temporary fixing spots 4 are formed by sequentially lightly welding the grooves 22 to such an extent that the position of the welding material 1 does not shift within the groove 2. At this time, not only the resin of the resin film 11b but also the groove 22 and its periphery are slightly melted to assist in forming the temporary fixing spot 4. The spot-like heating element is, for example, 180 to 200 using a hot iron.
It is simple to use one heated to a temperature of about ° C.
The temporary fixing spot 4 is usually a combination of a straight part 4a and a bent part 4b. For example, the straight part 4a has two places near a start point and an end point.
Although three places near the start point, the middle point, and the end point are selected for the bent portion 4b, the number can be reduced by also using each of them. In the example shown in FIGS. 3 and 5, the bent portions 4 b are all three places, and the lower left and right grooves 22 have a start point and an end point at one place of the right end straight part 4 a and one place of the left end bent part 4 b. Temporary spot 4
Are formed in the upper left and right grooves 22 at one location of the left end bent portion 4b and one location of the right end bent portion 4b. Spot 4
Is not provided. Usually, it is preferable to provide a linear portion 4a1 near the current inlet 1d and the outlet 1e for stabilization. The groove 22 is formed continuously by combining the straight portion 22a and the bent portion 22b. However, depending on the shape and size of the welded plastic materials 2 and 3, the straight portion 22a may need to be formed to intersect. There are cases. At this time, the temporary fixing spot 4 may be temporarily fixed at the intersection.
Further, here, the temporary fixing spot 4 may be formed by bonding instead of the welding. For example, a small amount (for example, 100 to 300 m) of a cellulosic or thermoplastic resin adhesive for temporary fixing is applied by a pressurized injector having a sharp inlet.
g) The temporary fixing spot 4 may be formed by locally injecting into the welding material 1 disposed along the groove 22 and lightly adhering to the groove 22 of the welding plastic material 2. As the thermoplastic resin adhesive for temporary fixing, a vinyl-based or acrylic-based adhesive is usually used. It is preferable to use a quick-drying adhesive for temporary fixing from the viewpoint of work efficiency. The final welding step is performed as shown by a two-dot chain line in FIG.
In (d), one welded plastic material 2 and the other welded partner welded plastic material 3 and the welded material 1 superposed thereon are combined, and the above-mentioned temporary fixing spot 4 is shown in FIG. The description is omitted to avoid congestion. Here, of the welding material 1 placed between the welding plastic materials 2 and 3, the upper part of the welding material 1 protruding from the groove 22 is an outer surface near the groove 22 due to the pressing of the base materials 21 and 31. As shown in FIG. 5 (d), the portion spreads slightly flatly as schematically shown by a broken line of a waveform. Crimping a smooth weld faces the base material 31 and the substrate 21 to fit heavy, but a pressure of about 1kg ^/ cm ² ~2kg / cm 2 by the entire normal welding surface for example pressing or spring-like presser It is preferable to press and bond,
3 is set according to the shape, size, and the like. If the pressure is insufficient, the welding force becomes uneven, and if the pressure is too large, the welded plastic material may be deformed. Next, current is passed through the through-holes 32 near the terminals of the current inlet 22c and the current outlet 22d of the base material 21 from the outside through a positive electrode and a negative electrode of an energizing device (not shown) separately prepared, and thereby both ends of the welding material 1 For example, a current of 80 to 110 volts
When electricity is supplied for a short time of about 0 second, the fiber bundle 11 of carbon fiber filaments is heated and generates heat, and the welded plastic material 2
3 are melted and welded to each other, and the vicinity of the through hole 32 is melted and closed by heating. The energizing conditions such as the current to be energized and the energizing time are set so that the welding surface can be firmly welded according to the length and thickness of the welding material 1 and the materials and sizes of the welding plastic materials 2 and 3. Is done. In this example,
Since the welding material 1 may be set along the groove 22, the welding material setting step can be performed efficiently and easily.
2 must be formed and it is for mass production.

In the first example of the welding method described above, the shapes of the welded plastic materials 2 and 3 are the same in plan view. However, this is not necessarily required, and at least the welded surfaces to be overlapped need only be smooth to each other. The shape of the surface opposite to the surface on which the welded plastic materials 2 and 3 are welded to each other is not limited to a flat surface as long as pressure can be applied to the entire welded surface. These are the second to fifth welding methods described later.
The same applies to the plastic materials used in the examples,
The same description below is omitted. The cross-sectional shape of the groove 22 does not necessarily have to be strictly symmetrical, but is preferably substantially symmetrical in terms of machining and uniform welding. The cross-sectional shape of the groove 22 is formed in a downwardly concave circular arc or other curve, the depth h is smaller than 1/2 of the apparent diameter d of the welding material 1 used as described above, and the width w of the surface is 1 mm. Although it is slightly larger than the apparent diameter d, in the welding step shown in FIG. The upper portion of the protruding welding material 1 spreads flatly on the left and right sides of the outer surface in the vicinity of the groove 22, and the widened portion allows the heating area by energizing the welding material 1 to be secured as much as possible. In order to reduce the air produced, the cross-sectional shape of the groove 22 is selected so that the air gap is reduced as much as possible.
This is achieved by a plurality of twists. On the other hand, if the depth h of the groove 22 is larger than 1/2 of the apparent diameter d of the welding material 1, a gap is formed around the groove, the welding is hindered, and the welding becomes insufficient.
The through hole 32 formed on the side of the welding plastic material 3 is omitted, and the current inlet 1d and the current outlet 1e of the welding material 1 are slightly protruded outward from the base 21 from the current inlet 22c and the current outlet 22d. In this state, the positive electrode and the negative electrode of the energizing device may be connected and conductive to energize, but in some cases, post-processing of a slightly protruding portion to the outside of the terminal may be necessary, and The use of the holes 32 is preferable because a beautiful finish can be obtained without the need for post-processing.

A second example of the welding method according to the present invention will be described. In the preparation process of the second example, in FIG.
The welded plastic material 2 ′ has a welding pattern of a plate-like thermoplastic base material 21 ′ and a portion to be welded over the smooth surface of the base material 21 ′, that is, a portion on which the welding material 1 is placed. A number of scribe lines 22 'continuously written along the scribe line and a large number of serrated narrow grooves 23' intersecting at right angles to the scribe line 22 'are engraved by, for example, a roller-type hot iron. . Here, the base material 21 'is of the same quality and shape as the base material 21 of the first example, and the score line 22' is
The pattern is the same as the pattern No. 2. It is preferable that the narrow grooves 23 'are provided orthogonally from the viewpoint of production and uniform effect, but they need not necessarily be orthogonal. Welding plastic material 3 'on the other side mated to welding plastic material 2'
As shown in FIGS. 2 (b) and 2 (b), the base member 31 includes a base material 31 'and a through hole 32' having the same configuration as the plastic material 3 to be welded. In the welding material setting and temporary fixing process, FIG.
(B) As shown in bc), the welding material 1 is placed along the score line 22 ', and the temporary fixing spot 4 is formed by welding or bonding as in the first example. Here, since the tip portion of the sawtooth of the narrow groove 23 'is thin, heat is transmitted well, and the surface area is increased, so that the temporary fixing spot 4 can be quickly formed by welding. As shown in FIGS. 2 (b) and bc), the welding material 1 is completely exposed on the surface of the welding plastic material 2 '. In the welding step, as shown by a two-dot chain line in FIG.
The flat welding surface is overlapped and pressure-bonded, and the electrode is heated from the outside through the through-hole 32 'through the electrodes of the current-carrying device. The pressure condition is usually set higher than in the first example. This is welding material 1
Is completely exposed on the surface of the welded plastic material 2 ′ and spreads to the left and right of the scored line 22 ′ by applying pressure so that a heating area can be ensured as much as possible by energizing the welded material 1. . The energization conditions are usually set in the same manner as in the first example. Welded plastic material 2 'and 3'
The shape, through-hole 32 ', etc. are the same as described in the first example. In this example, the welding material 1 is moved along the score line 22 '.
The welding pattern can be set and changed efficiently and easily, but the positioning of the welding material 1 in the welding material setting and temporary fixing step may become unstable, so it must be performed carefully.

Referring to FIG. 4, a description will be given of a third example of the welding method of the present invention using another method instead of forming the temporary fixing spot 4 in the above-mentioned temporary fixing step. In the following description, only one location is described.
Other portions corresponding to the second bent portion 22b are similarly used at a plurality of appropriate positions. In the preparation step, in FIG. 4 (a), two score lines 22 'perpendicular to the upper surface corners of the base material 21' are drawn using the one welded plastic material 2 ', and the score lines 22 are formed. 'Divide the right angle of intersection 4
Width a, depth b, which is opened with a longitudinal portion in the direction of 5 degrees,
A rectangular fitting groove 53 having a depth f is formed. FIG.
(B) shows a locking tool 5, which is made of plastic of the same quality as the welded plastic material 2 ', and has a width a, a depth b, and a height c, which is the upper center of a rectangular main body 51. Rectangular slit 5 with width s, depth b, and depth e with an opening at the part
2 are drilled. Here, each dimension is approximately “f
= Ce ”. The width s of the slit 52 is usually set to 0.3 to 0.5 mm, and is set to be equal to or less than the apparent diameter d of the welding material 1 which is usually used.
Then, as shown in FIG.
The lower part 1 is press-fitted and embedded so that the upper part of the main body 51 including the slit 52 is protruded from the surface of the base 21 ′. As shown in FIG. 4D, an opening is formed at a corner corresponding to the fitting groove 53 of the welded plastic material 2 'at the lower corner of the base material 31' using the other welded-side welded plastic material 3 '. A rectangular fitting groove 54 having a width a ′, a depth b ′, and a depth e is formed, and a ′> a,
b '> b. The portion corresponding to the fitting groove 54 and the upper portion of the main body 51 including the slit 52 of the locking tool 5 fitted to the fitting groove 54 has a slightly larger fitting groove 54 side to facilitate fitting. is there. Here, the main body 51 may be bonded to the base material 21 'of the welded plastic material 2' or may be integrally formed without being embedded in the rectangular groove 53. Although the installation of the locking device 5 has been described for the portion corresponding to the bent portion, the current inlet 22c and the current outlet 22d
The surface of the main body 51 is orthogonal to the score line 22 ', and the inside of the slit 52 is marked with the score line 22'.
Are arranged to pass in a straight line. The welding material setting and the temporary fixing step are performed from above the slit 52 having the width s.
The middle part is pushed in while applying some tension, and both ends are arranged along the score line 22 'and temporarily fixed in the same manner as in the second example, and the welding material 1 is sequentially inserted into the slit 52 of another adjacent main body part 51. To temporarily fix the welding material and complete the welding material setting and the temporary fixing. The width s of the slit 52 is set to be equal to or less than the apparent diameter d of the welding material 1 and the welding material 1 has an appropriate bulky property. Is held. In the welding step, the upper part of the locking tool 5 projecting into the fitting groove 54 is fitted, and the fitting groove 54 is sequentially fitted to the other adjacent locking tool 5 as well. And 3 'can be easily, quickly and reliably welded by pressing and energizing the through-hole 32' through the electrode of the energizing device from the outside while pressing the same as in the second example. The pressure and energization conditions are set in the same manner as in the second example. The locking device 5 is of the same quality as the welded plastic material 2 ',
Eventually, there is no quality problem because it is melted and homogenized inside the substrates 21 'and 31'. The shapes of the welded plastic materials 2 'and 3', the function of the welded material 1, the through-holes 32 'and the like are the same as in the second example. In this example, it is necessary to prepare and embed the stopper 5, but it is suitable for mass production because the welding material setting step is simple.

Referring to FIG. 6, fourth and fifth examples of a welding method suitable for welding plastic materials having narrow welding surfaces and corners crossing substantially in an L-shape will be described. First, a fourth example of the welding method of the present invention will be described with reference to FIG. One welded plastic material 7 is made of a pair of base materials 71 that intersect at a substantially right angle.
A narrow groove 72 having a width w and a depth h similar to that of the groove 22 and having an arc-shaped cross section is cut into the upper end surface 74 of the base material 71 to be welded. As shown in FIG. 6 (a) ad), the length n of each side on the surface of the intersection corner of
An arc-shaped corner groove 73 having a depth k and a width w which is tapered at the bottom and viewed from the front is formed, and is continuous from the current inlet 72a of the base material 71 to the current outlet 72b via the corner groove 73. The other welding partner-side welded plastic material 6 has a pair of base materials 61 intersecting at substantially right angles and a lower end face 63 at the intersection corner as shown in FIG.
As shown in (a) ac), each side has a lower end tapered corner projection 62 having a length j, height i, and width w. In this example, the corner projection 62 is embedded in the groove formed in the base material 61 from the lower end face 63 side with an extended portion above the corner projection 62, but is not necessarily limited to this configuration. The corner protrusion 62 may be formed in advance integrally with the base material 61 or may be formed by bonding or welding. Where k> h, n> j,
k> i, and a clearance is provided between the corner groove 73 and the corner protrusion 62 so that the corner groove 73 and the corner protrusion 62 can be loosely fitted.
Corresponding to the volume. Then, FIG.
(A) As shown in ab), the welding material 1 is successively placed in the groove 72 and the corner groove 73 in the order of the linear portion 1a → the bent portion 1b → the linear portion 1a, and is placed near the current inlet 72a and the current outlet 72b. A temporary fixing spot is formed at both ends of the linear portion 1a, and the bent portion 1b of the welding material 1 is temporarily fixed to the corner groove 73 by pushing a spot-like heating element. Then, the lower end face 6 of the welded plastic material 6
3 is superposed on the upper end surface 74 of the welded plastic material 7 with the welding material 1 interposed therebetween, and is pressed and heated from both ends on the outside of the welding material 1 through the electrodes of the current-carrying device. At this time,
A current inlet 72a and a current outlet 72 are provided at both end surfaces of the base material 61.
It is preferable that a pair of through holes 64 is formed obliquely toward the vicinity of b, and the electrodes are passed through the through holes 64 and heated by heating. Here, the pressure condition is usually 0.5 kg / cm ^{2 to} 1 kg / c.
It is set rather low of about m ^2, energization conditions, for example 30
The current of 80 volts is set as low as about 5 to 10 seconds, in order to cope with welding of the welded plastic materials 6 and 7 on a thin surface. Since the welding material 1 has high elasticity, it is difficult to bend when bent at a substantially right angle.
By pushing the bent portion 1b of the welding material 1 into the deeper corner groove 73, the two-dimensional bending can be alleviated by the three-dimensional bending, and exists between the corner groove 73 and the corner projection 62. Since the clearance corresponds to the volume of the welding material 1, easy, quick,
Can be securely set and welded. Here, the base materials 61 and 71 intersect at a substantially right angle, but the intersection angle is not limited to the substantially right angle. The shapes of the welded plastic materials 7 and 8, the operation of the welded material 1, the through holes 64, and the like are the same as those described in the first example. The intersecting bases 61 do not necessarily have to be a pair of the same shape and the same size, and the same applies to the base 71. According to the present embodiment, it is possible to perform firm welding of the welded plastic materials 6 and 7 on a thin surface.

Next, a fifth embodiment of the welding method according to the present invention will be described with reference to FIG. One welded plastic material 9 has a pair of bases 91 that intersect at a substantially right angle, and an upper end surface 93 of each base 91 to be welded having a width w and a depth h similar to the linear grooves 22 throughout the entirety. A continuous narrow groove 92 having an arc-shaped cross section is engraved, and each groove 92 intersects in a substantially cross shape at the surface of the intersection corner of the upper end surface 93 as shown in FIG. The other welding partner side welding plastic material 8 is
As shown in FIGS. 6A and 6B, the lower end surfaces 82 of the pair of base materials 81 that intersect at substantially right angles are flat and have a size that can be overlapped with the upper end surface 93. As shown in FIGS. 6 (b) and bb), the welding material 1 is continuously and linearly placed in one of the grooves 92, and is temporarily fixed to the vicinity of the current inlet 92a and the current outlet 92b by a spot-shaped heating element. The welding material 1 is continuously and linearly placed in the other groove 92 intersecting at the current inlet 9.
2c and near the current outlet 92d are temporarily fixed by a spot-shaped heating element. The lower end surface 82 of the welded plastic material 8 is interposed between the lower end surface 82 of the welded plastic material 8 and the upper end surface 93 of the welded plastic material 9.
Heating is performed through both electrodes on the outside of the welding material 1 through the electrodes of the current applying device while being overlapped and pressed, or four through holes are formed in both side end surfaces of the base material 81 similar to the through holes 64 although not shown. Then, the welding plastic materials 8, 9 can be easily, quickly and reliably set and welded by applying an electric current to the through holes through electrodes. The pressure and energization conditions are set in the same manner as in the fourth example. Here, the base materials 81 and 91 intersect at a substantially right angle, but the intersection angle is not limited to the substantially right angle. The shapes of the welded plastic materials 8 and 9 and the operation of the welded material 1 are the same as those described in the fourth and first examples. The intersecting bases 81 do not necessarily have to be a pair of the same shape and the same size, and the same applies to the base 91. According to the present embodiment, it is possible to perform firm welding of the welded plastic materials 8 and 9 on a thin surface. Comparing the fourth and fifth examples, the fourth example requires only one energization, but the fifth example requires two energizations. However, in the fourth example, the corner groove 73 and the corner projection 62 must be provided, and in the fifth example, only a pair of linear grooves 92 need to be provided.

[0015]

[Embodiment 1] The welding method of the first embodiment described with reference to FIGS. First, in the preparation process,
1000 filaments, 66 tex count (g
/ 1000 m) of carbon fiber bundle 11a (Torae T300, manufactured by Toray Industries, Inc.) is impregnated by immersing in a water-soluble emulsion solution of a polyvinyl acetate resin (for Bond A woodworking, manufactured by Konishi Co., Ltd.) and squeezed by a squeezing roller. After drying, a raw yarn 11 having a resin coating 11b on at least the surface was obtained.
The resin impregnation amount at this time was 80 mg / m, and the resin coating 11
The thickness of b was in the range of 0.01 mm to 0.02 mm. The raw yarn 11 is twisted 394 times / m (10 times / inch)
Thus, a welded material 1 of a two-ply strong twist twin yarn was obtained. The apparent diameter d of the welding material 1 was a substantially circular cross section of 0.5 mm.
A pair of polyacrylic welded plastic materials 2 and 3 having a smooth surface of length 100 mm, width 65 mm and thickness 2 mm
And a continuous width of 0.5 mm and a depth of 0.2 on the whole surface of the base material 21 of one of the welded plastic materials 2.
An arc-shaped thin groove 22 shallower than 1/2 of the apparent diameter d of the welding material 1 of mm was cut. The groove 22 has a straight portion 22a, a bent portion 22b, and a current inlet 22c substantially similar in shape to FIG.
And a current outlet 22d are formed.
R of about m is attached. Next, in the welding material setting and temporary fixing step, the welding material 1 is placed along the groove 22 and
a, the bent portion 1b, the current inlet 1c, and the current outlet 1d, the portions as described above with reference to FIGS. 3 and 5 (c) are selected as the temporary fixing spots 4 and the linear portions 4a and the bent portions 4b have 160 to 200 points. Using a hot iron heated to about ° C., the tip is pushed in such a manner as to pierce the center of the welding material 1, lightly welded to the plastic material 2 to be welded, and temporarily fixed to the welding material 1 along the groove 22. Was formed. In the final welding step, the smooth welding surface of the other welding plastic 3 and the surface of the welding plastic material 2 on the groove 22 side are overlapped with each other, and a pressure of 1.5 kg / cm ² is applied with a spring-like presser to give a diameter of 2 mm. When a current of 80 volts is applied to the current inlet 1c and the current outlet 1d for 8 seconds through the through hole 32 by the current applying device for 8 seconds, the fiber bundle 11a is heated, and the carbon fibers generate heat. The resin film layer 11b was melted at the peripheral portion and at the same time, the resin coating layer 11b was also melted and the welded plastic materials 2 and 3 could be firmly welded into the twist. [Comparative Example] For comparison, using the same welding plastic materials 2 and 3 and the welding material 1 as in Example 1, the depth of the groove 22 continuously cut into the entire surface of the base material 21 was set to the depth of the welding material 1. 0.4 mm deeper than の of the apparent diameter d, where temporary fixing, pressing and welding were performed under the same conditions as in Example 1, the welding power was weak, and the welded plastic materials 2 and 3 were peeled off. I destroyed it and examined it. As a result, when the depth of the groove 22 is large, a gap is formed around the groove 22 when the welded plastic materials 2 and 3 are overlapped and pressurized, and it is considered that the remaining air there is a factor inhibiting welding.

Embodiment 2 The welding method of the second embodiment described with reference to FIG. 2B was used. First, a pair of polyacrylic welded plastic materials 2 'and 3' having the same dimensions and the same quality as those in Example 1 are prepared, and the base material 2 of one welded plastic material 2 'is prepared.
A scribe line 22 'was written in substantially the same pattern as the groove 22 of the first embodiment as a portion to be welded over the entire surface of the 1' (the portion on which the welding material is to be placed) to form a welding line. Sawtooth-shaped width 3 mm orthogonal to this score line 22 ′
Were formed by a roller-type hot trowel. The configuration of the welded plastic material 3 'is the same as that of the welded plastic material 3 of the first embodiment, and the formation of the temporary fixing spot 4 by heating is performed in the same manner as in the first embodiment along the welding line sequentially.
A welding material setting and temporary fixing step were performed. In the welding step, a pressure of 2.0 kg / cm ² is applied to the welded plastic materials 2 ′ and 3 ′ using a spring-like presser, and
When an electric current of 80 volts is applied for 8 seconds by an energizing device through 2 ', the fiber bundle 11a is heated and the carbon fibers generate heat,
The welded plastic materials 2 'and 3' could be firmly welded. [Embodiment 3] Although not shown, using the same polyacrylic welding plastic materials 2 'and 3' as in the embodiment 2, the temporary fixing spot 4 was formed by a small amount of an acrylic resin-based adhesive without using a hot iron. 100 to 300 mg) In the same manner as in Example 2, except that local injection was performed by a pressurized injector and lightly adhered along the score line 22 ′ of the base material 21 ′, the welded plastic material 2 ′ and 3 'could be firmly welded.

Example 4 The welding method of the third example described with reference to FIG. 4 was used. Using the same polyacrylic welding plastic materials 2 'and 3' as in Example 2,
In addition, width a: 3 mm, depth b: 0.5 mm, depth f:
A fitting groove 53 of 0.5 mm was provided. The locking member 5 is made of polyacryl of the same quality as the welded plastic material 2 'and has a width a: 3.
mm, depth b: 0.5 mm, height c: 2 mm, and a rectangular main body 51 having a width s: 0.5 mm, a depth b: 0.5 mm, and a depth e: 1.5 mm in the upper central portion. The main body 51 was press-fitted into the fitting groove 53 and embedded therein. On the other hand, a rectangular fitting groove having a width a ': 3.5 mm, a depth b': 0.8 mm, and a depth e: 1.5 mm is formed in the base material 31 'at a position corresponding to the fitting groove 53. 54 were drilled. In the welding step, the welded plastic materials 2 'and 3' are superimposed on each other and 2.0 k
When a pressure of g / cm ² is applied and a current of 80 volts is passed through the through-hole 32 ′ for 8 seconds by a current-carrying device, the fiber bundle 11 a is heated and the carbon fibers generate heat, and the welded plastic materials 2 ′ and 3 ′ are firmly welded. We were able to. The fastener 5 of the same quality as the welded plastic material 2 '
It was homogenized inside 1 ', 31'.

Embodiment 5 The welding method of the fourth embodiment described with reference to FIG. 6A was used. A polyacrylic welded plastic material 7 having a pair of base materials 71 having a side length of 60 mm, a vertical width of 20 mm, and a thickness of 2 mm crossing at a substantially right angle intersects a pair of base materials 61 of the same shape, the same size and the same at a substantially right angle. A welded plastic material 6 was prepared. Most of the upper end surface 74 of the base material 71 is straight and has a continuous arc-shaped groove 72 having a width w: 0.5 mm and a depth h: 0.2 mm.
As shown in (a) ad), a bottom groove 73 having a tapered bottom portion having a length n: 2 mm, a depth k: 1 mm, and a width w: 0.5 mm and having an arc shape as viewed from the front was formed. On the other hand, on the lower end face 63 at the intersection corner of the base material 61, the length j of each side is 1.8 mm, the height i is 0.8 mm, and the width w is as shown in FIG.
A 0.5 mm corner projection 62 was projected. In the welding material setting and temporary fixing step, first, the welding material 1 is temporarily fixed to the vicinity of the current inlet 72a by a hot iron, and the corner groove 73 is pressed temporarily into a deep groove by a hot iron and temporarily fixed. The welding material 1 was temporarily fixed to the vicinity of 72 b by a hot iron and placed along the groove 72. In the welding step, the welded plastic materials 6 and 7 are superimposed on each other and a pressure of 0.5 kg / cm ² is applied by a spring-shaped retainer. Current of 8
When electricity was supplied for 2 seconds, the fiber bundle 11a was heated and the carbon fibers generated heat, and the welded plastic materials 6 and 7 could be firmly welded on the surface having a thickness of 2 mm.

Embodiment 6 The welding method of the fifth embodiment described with reference to FIG. 6B was used. Welded plastic materials 8 and 9 of the same shape, size and quality as in Example 5 were prepared. A linear width w over the entire upper end surfaces 93 of the pair of base materials 91:
A continuous narrow groove 92 having an arc-shaped cross section of 0.5 mm and a depth h: 0.2 mm was formed. The grooves 92 intersect at a substantially right-angle cross as shown in FIG. 6B and bc) on the surface of the intersection corner. On the other hand, as shown in FIG. 6 (a) and ba), the lower end surface 82 of the mating side is flat and can be overlapped with the upper end surface 93. In the welding material setting and temporary fixing step, FIG.
As shown in b), the welding material 1 is linearly placed in one groove 92 while continuously applying tension thereto, and temporarily fixed to the vicinity of the current inlet 92a and the current outlet 92b by a hot trowel. Similarly, the welding material 1 is placed linearly and the current inlet 9
2c and near the current outlet 92d were temporarily fixed by a hot iron. In the welding step, the welded plastic materials 8 and 9 are superimposed and a pressure of 0.5 kg / cm ² is applied by a spring-like presser. First, one of the welded materials 1 is placed near the current inlet 92 a and the current outlet 92 ^{b by} a current supply device. A current of 30 volts is applied for 8 seconds to weld one of the base materials 81 and 91, and then a current of 30 volts is applied to the other welding material 1 in the vicinity of the current inlet 92a and the current outlet 92b by a current supply device for 8 seconds. Thus, the other base materials 81 and 91 were welded, and the welded plastic materials 8 and 9 could be firmly welded on a surface having a thickness of 2 mm.

[Example 7] Two fiber bundles 11a having the same structure as in Example 1 were used as raw yarns without forming the resin coating 11b, and the number of twists was 472 times / m (12 times / inch). A twisted strong twisted double yarn welding material was obtained. Using the same polyacrylic welding plastic materials 2 and 3 as in Example 1, the formation of the temporary fixing spots 4 was performed by using a small amount (100 to 300 mg) of an acrylic resin-based adhesive by a pressurized injector without using a hot iron. The welding was carried out in the same manner as in Example 1 except that the injection was performed and lightly adhered to the groove 22. The welding material used was a strong twist twin yarn of the original yarn, and although looseness and fluffiness were considerably suppressed, there was still a little left because it did not have the resin coating 11b, so handling in the setting process required some attention. However, the welded plastic materials 2 and 3 could be firmly welded.

[0021]

According to the method for welding plastic materials of the present invention, since carbon fibers which are organic substances remain in the welded portions of the welded plastic materials at the time of recycling, they can be reused together with conventional nichrome. There is no need to pull out and process from the welded plastic material as in welding by using wires, and it is environmentally friendly, low cost and requires no labor. or,
The welding material to be used is a strong twist of carbon fiber bundles. It has a moderate degree of plasticity that suppresses loosening, fluffing, bending, etc., and is easy to handle. The set, temporary fixing and welding steps are excellent in workability and can be easily and reliably performed.

[Brief description of the drawings]

FIG. 1 is a schematic view schematically showing a part of an example of a welding material used in a welding method of the present invention, wherein (a) is a front view, and (b) is AA.
It is sectional drawing.

FIG. 2 is a schematic perspective view of a step of preparing a welded plastic material used in the welding method of the present invention, and (a) a of the first example;
a) One side, ab) a welding partner side, ac) a schematic sectional view around a groove in which a welding material is set. Also, (b) b of the second example
FIG. 3 is a schematic cross-sectional view around a score line where a) one side, bb) a welding partner side, and bc) a welding material is set.

FIG. 3 is an explanatory view of a welding material temporary fixing step in a first example of the welding method of the present invention and a plan view.

FIG. 4 is an explanatory view of a welding material temporary fixing step in a third example of the welding method according to the present invention, wherein (a) a base material before fitting of a locking tool, (b) a locking tool, and (c) a fitting of a locking tool. It is a perspective view of the base material after adhesion | attachment, and (d) each one part of the welding partner side.

5 is a left side view, a plan view, and a right side view of a welding material and a welding plastic material in each step from the left side in the schematic explanatory view of the first example of the welding method of the present invention, and FIG. One side plastic material, (b) one side plastic material in the welding material setting step, (c) one side plastic material in the welding material temporary fixing step, and (d) one side of the welding step and the other side plastic material are shown.

FIG. 6 is a schematic explanatory view of the welding method according to the present invention in the case where the welding method has a crossing corner, and (a) aa) a welding partner side, ab) of the fourth example.
FIG. 2 is a perspective view of one side, partially enlarged view of ac) aa), and partially enlarged view of ad) ab). In the fifth example, (b) ba) welding partner side, bb) one side, bc) bb)
3 is a partially enlarged view of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Welding material 11 Yarn 11a Fiber bundle 11b Resin coating 2, 2 ', 3, 3', 6, 7, 8, 9 Welding plastic material 21, 21 ', 31, 31', 61, 71, 81, 91
Substrates 22, 72, 92 Grooves 22 'Ruled lines 23' Fine grooves 11a, 22a, 4a Linear portions 11b, 22b, 4b Bend portions 1c, 22c, 72a, 92a, 92c Current inlets 1d, 22d, 72b, 92b, 92d Current outlet 4 Temporary fixing spot 5 Locking tool 51 Main body 52 Slit 53, 54 Fitting groove 62 Corner projection 73 Corner groove d Apparent diameter s Slit width

Claims (12)

[Claims] 1. A welding material in which a plurality of substantially untwisted fiber bundles made of carbon fiber filaments are twisted to form a welding material, and a current is applied to at least one surface of one and the other welding plastic materials having a smooth welding surface. 1 / of the apparent diameter of the welding material reaching the current outlet continuously from the inlet to the whole.
A groove having a depth shallower than 2 is provided, the welding material is continuously arranged in the groove, and temporary fixing spots are formed at a plurality of appropriate places of the welding material. A method for welding plastic materials, characterized in that currents are applied to the ends of the welding material while the surfaces are overlapped and pressed together, and the welded plastic materials are welded to each other by heating the fiber bundle. 2. A fiber yarn in which a fiber bundle in which a welding material is substantially untwisted is impregnated with a cellulosic adhesive or a thermoplastic resin adhesive and dried to form a resin film on at least a surface portion of the fiber bundle. 2. The method for welding plastic materials according to claim 1, wherein a plurality of fibers are twisted. 3. A fiber bundle in which a welding material is substantially untwisted, a plurality of fiber bundles are twisted, and then a cellulose-based adhesive or a thermoplastic resin adhesive is impregnated and dried to form a resin coating on at least a surface portion of the fiber bundle. Is formed.
2. The method for welding plastic materials according to item 1. 4. The twisting of the fiber bundle or the raw yarn is set to 2000 to 5500 in the number of twists per meter and the twisting factor calculated by the tex count. 2. The method for welding plastic materials according to item 1. 5. The method for welding a plastic material according to claim 1, wherein a cross-sectional shape of the groove is a substantially symmetrical downward concave shape. 6. A scribe line extending continuously from the current inlet to the current outlet is provided in place of the groove provided on one surface of the welding plastic material, and the welding material is continuously arranged along the scribe line. The method for welding a plastic material according to claim 1, wherein: 7. The method of welding a plastic material according to claim 6, wherein a plurality of serrated narrow grooves intersecting with the scribe line are formed. 8. The welding method for a plastic material according to claim 1, wherein the temporary fixing spot is formed by locally heating the welding material with a spot-shaped heating element. 9. The plastic according to claim 1, wherein the temporary fixing spot is formed by bonding in which a small amount of a cellulosic or thermoplastic resin adhesive is locally injected into a welding material by an injector. Material welding method. 10. A welding material in which a plate-shaped main body member provided with a slit having an upper opening is protruded in one groove or a plurality of appropriate positions on a scribe line of a welding plastic material instead of forming a temporary fixing spot. The main body member is fitted into the fitting groove by overlapping one of the welding plastic material with the other of the welding plastic material having a fitting groove formed in the lower surface thereof. Item 8. The method for welding a plastic material according to any one of Items 1 to 7. 11. A welded plastic material composed of a base material that intersects substantially in an L-shape, wherein one and the other of the welded plastic material are used. A corner groove deeper than the arc-shaped groove is formed in continuity with the groove, and a current at the other end of the groove is formed from a current inlet at one end of the one groove of the welded plastic material via the corner groove. The welding material is disposed continuously to the outlet, and the other of the welding plastic materials provided with corner projections to be loosely fitted corresponding to the corner grooves is overlapped with one of the welding plastic materials and press-bonded. 6. An electric heating is applied to an end of the base material to weld the plastic materials to each other.
The method for welding a plastic material according to any one of the above. 12. Using one and the other of a welding plastic material made of a base material that intersects substantially in an L-shape, a linear groove is provided in the upper end surface of one of the base materials of the welding plastic material so as to intersect therewith. A welding material is continuously arranged from the current inlet at one end of the groove where the material intersects to the current outlet at the other end of the groove, and the welding is performed from the current inlet at the other end of the groove where the base intersects. The welding material is disposed continuously to the current outlet at the other end of the groove, and the other end of the welding plastic material is first applied to one end of the welding material on the one side of the base material while being press-bonded while being overlapped with one, The method for welding plastic materials according to claim 1, wherein the welding plastic materials are welded to each other by applying electric current to the end of the welding material on the other side of the base material.