JPH0780243B2 - Method and fitting for attaching joint to thermoplastic resin container - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of attaching a joint to a container made of thermoplastic resin, and more particularly to a method of heat fusion. The invention is also directed to a joint which is advantageously applied in such a method.

[0002]

2. Description of the Related Art For example, in a factory or the like, a tank having a diameter of 1 m or more, or more than 2 m is used to store water or liquid chemicals. Such a tank is made of polyethylene, for example, and is usually manufactured by rotational molding.

To take out the liquid from the tank as described above, a through hole is provided at a desired position on the outer peripheral wall of the tank, a joint is fitted in the through hole through a packing or the like, and a double nut bolt is used. The joint was attached to the tank by tightening it from the outside. Therefore, the necessary piping has been done through such a joint.

However, the above-mentioned method has a drawback that the work for mounting the joint takes a relatively long time. The material of the packing used must be selected according to the properties of the liquid contained in the tank. Furthermore, if the tightening with the double nut bolt is incomplete, or even if the tightening is complete,
When the fitting between the joint and the tank is incomplete, the packing does not serve its purpose, and liquid in the tank may leak from the joint between the tank and the joint. Leakage may also occur due to the deterioration of the packing and other changes over time in the joint. For this reason, in the field where the tank is used, it is the current situation that it is difficult to take measures against liquid leakage.

On the other hand, recently, when manufacturing a tank made of polyethylene, it has been partially adopted to integrally mold a portion having a shape as a joint. According to this method, unless the joint part is damaged, liquid leakage does not occur, reliability for liquid leakage prevention is improved, and no separate joint or packing is required, and these are mounted on the tank. Work is also unnecessary, so
The advantage is that it also leads to cost reduction.

However, it has been found that even if the above method is adopted, the following problems are encountered.

That is, when the tank is molded, the position and size of the joint portion are already determined, and due to the method of molding the tank such as rotational molding, the number of joint portions that can be formed is also limited. ing. Therefore, it is often not possible to ideally position the joints to fit the purpose at each of position, number and size. Therefore, in the field, it is necessary to pipe according to the position, number and dimensions of the joint part on the tank side, and as a result, unnecessary pipe parts are required, bypass piping is made, and unnecessary joint parts are removed. I may leave it.

[0008]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method of attaching a joint to a thermoplastic resin container which can solve all the problems described above, and a joint which is advantageously used in this method. Is to provide.

[0009]

The method for attaching a joint to a thermoplastic resin container according to the present invention comprises the following steps in order to solve the above-mentioned technical problems.
That is, (1) a container made of a thermoplastic resin is prepared, and the container is made of a thermoplastic resin that can be heat-sealed to the thermoplastic resin, and a flange and a projecting portion further projecting from the flange are provided at one end thereof. A step of preparing a joint in which a tapered taper is provided on the outer peripheral surface of the bulge portion, (2) The tip diameter of the taper of the bulge portion is approximately the same as a desired position of the container. Providing a through hole having a diameter and not having a taper, (3) heating and melting the peripheral portion of the through hole by a heater face having a taper in the same direction as the taper of the overhanging portion, and the through hole Heating and melting the end of the joint that is in contact with the peripheral edge of (4), while positioning the projecting portion in the melted through-hole, toward the peripheral edge of the through-hole. The step of pressing the end portion of the fused joint, thereby fusing the thermoplastic resin on the container side and the thermoplastic resin on the joint side together, and (5) Next, the fused container and the The step of cooling the joint with the joint is provided. Further, the present invention is also directed to a joint which is attached to a through hole provided in a thermoplastic resin container by thermal fusion bonding, and the joint is made of a thermoplastic resin and has an end to be thermally fused with the container. The portion is provided with a flange and a protruding portion that further projects from the flange, and a tapered taper is given to the outer peripheral surface of the protruding portion.

As the thermoplastic resin forming each of the above-mentioned container and joint, polyethylene, polypropylene, polycarbonate or the like can be used. In order to enhance the strength of fusion bonding between the container and the joint, it is preferable that the thermoplastic resin forming the container and the thermoplastic resin forming the joint are made of the same material.

[0011]

According to the present invention, the joint is attached to the container by melting the thermoplastic resin on the container side and the thermoplastic resin on the joint side together and press-bonding them. More specifically, one end of the joint is provided with a flange and a projecting portion further projecting from the flange, and since the outer peripheral surface of the projecting portion is provided with a taper, it is provided on the container. When the end portion of the joint is brought closer to the peripheral edge portion of the formed through hole, the overhanging portion can be smoothly positioned in the through hole while being guided by this taper. Further, the through hole provided in the container has a diameter substantially equal to the tip diameter of the taper of the overhang portion, and the through hole is not tapered,
On the other hand, the peripheral portion of the through hole is heated and melted by the heater face having a taper in the same direction as the taper of the overhang portion, so that the inner peripheral surface of the through hole is melted more on the side where the joint is attached. . In this way, when the flange of the joint is pressed toward the peripheral portion of the through hole, the thermoplastic resin on the container side and the thermoplastic resin on the joint side are heat-sealed.

[0012]

Therefore, according to the present invention, it is possible to attach any number of joints of any size to a container at any place. Therefore, depending on the application, the position and size of the joints can be adjusted. And you can choose the number freely. Therefore, unlike the conventional tank having a joint part formed by integral molding, there is no restriction that piping must be performed according to the position and size of the preformed joint part, and an extra joint part is left. It is possible to efficiently perform the optimum piping without the waste of.

Further, it becomes easy to properly align the joint with the through hole by the action of the taper given to the overhanging portion, and moreover, in the peripheral portion of the through hole, more joints are provided on the side where the joint is attached. Since it is melted, the molten thermoplastic resin can be efficiently used to form the joint between the container and the joint. Therefore, the joint portion between the container and the joint obtained by fusion bonding can provide strength comparable to or more than that of integral molding. Therefore, it is possible to expect high reliability in preventing liquid leakage. For example, when the joint portion is formed integrally with the container based on rotational molding as in the conventional art, the joint portion and the boundary between the joint portion and the container body are made thin, and accordingly mechanical strength becomes a problem. However, according to the present invention, there is no anxiety that such a thin portion undesirably occurs.

Further, as compared with the case where the joint is mounted with the double nut bolt using the conventional packing, the work for mounting the joint is completed in a short time, and the packing is not required. Therefore, the cost can be reduced.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 6 are for explaining one embodiment of the present invention.

In carrying out this embodiment, FIG.
The fusing apparatus 1 as shown in FIG. The fusing device 1 is
The vacuum pad 2, the heater 3, the holder 4, and the pressurizing mechanism 5 are provided. In this embodiment, the container has a capacity of 60.
A 00 liter polyethylene tank 6 is used,
As a joint to be attached to this, JIS 1
A joint 7 corresponding to a joint with a flange of 0K-50A is used.

In the fusing device 1, the vacuum pad 2 is attached to an arbitrary position on the outer peripheral wall 8 of the tank 6 based on vacuum adsorption.
Can be fixed. Such vacuum pressure is applied by turning on the switch 9 provided in the vacuum pad 2.

The vacuum pad 2 is also provided with a through hole 10 for exposing a predetermined portion of the outer peripheral wall 8 of the tank 6.
The size of the through hole 10 is selected so that the heater 3 or the joint 7 can be received.

Further, on both sides of the through hole 10 of the vacuum pad 2, there are provided bosses 13 and 14 for receiving the slide bars 11 and 12, respectively. Set bolts 15 and 16 are held on the bosses 13 and 14, respectively.

Further, a heater receiving plate 17 is attached to the upper end surface of the vacuum pad 2. A groove 18 is provided in the heater receiving plate 17.

The details of the holder 4 and the pressing mechanism 5 are shown in FIG.
Is shown in. The holder 4 is for holding the joint 7 in a positioned state, and the pressurizing mechanism 5 is for applying pressure to the joint 7 through the holder 4 in the direction toward the outer peripheral wall 8 of the tank 6. belongs to.

The joint 7 has flanges 19 and 20 of different sizes at each end, as is best shown in FIG. A relatively small flange 19 is provided at the end portion to be fused with the tank 6, and further projects from this flange 19 to form an overhanging portion 21 having a taper on its outer peripheral surface. It As shown in FIG. 1, the other relatively large flange 20 is provided with, for example, four mounting holes 22.
Further, the flange 20 is reinforced by a plurality of ribs 23.

The holder 4 includes a pedestal 24 that receives the flange 20 of the joint 7. The joint 7 is positioned with respect to the holder 4 by screwing the set bolt 25 into the pedestal 24 through a mounting hole 22 formed in the flange 20. The set bolt 25 preferably comprises a knurled head so that it can be rotated without the use of special tools.

The holder 4 is further provided with a spring casing 2
6 is formed. A coil-shaped compression spring 27 is arranged in the spring casing 26. Further, one end of the connecting shaft 28 is inserted into the spring casing 26. The coupling shaft 28 has a coil-shaped compression spring 27 disposed around the spring in the spring casing 26, and forms a flange 29 that abuts one end of the compression spring 27. The other end of the compression spring 27 is in contact with the end wall 30 of the spring casing 26. The connecting shaft 28 extends through the end wall 30 to the outside of the spring casing 26, and forms a flange 31 at the end located outside the spring casing 26. In this way, the connecting shaft 28 is
As indicated by an imaginary line in FIG. 3, the compression spring 27 can be displaced in the direction of the arrow 32 with respect to the holder 4 against the elasticity.

As shown in FIG. 2, the other end of the connecting shaft 28 is received in the cam casing 33 provided in the pressing mechanism 5. The connecting shaft 28 includes a cam casing 33.
A flange 34 serving as a cam follower is formed therein. In the cam casing 33, a cam 37 fixed to a handle shaft 36 that provides a rotation center of a rotatable handle 35 is arranged. As shown in FIG. 1, the handle 35 extends to the outside of the pressurizing mechanism 5 and can be rotated about 90 degrees in a direction indicated by an arrow 38. Thus, when the handle 35 is rotated, the cam 37 acts on the flange 34 to displace the connecting shaft 28 in the direction of the arrow 32 as described above, as indicated by an imaginary line in FIG.

Referring to FIG. 1, holder 4 and pressurizing mechanism 5 holding it are slidable along slide bars 11 and 12. The pressurizing mechanism 5 can be fixed at two specific places on the slide bars 11 and 12. As described above, the operation for fixing the pressurizing mechanism 5 on the slide bars 11 and 12 is given by the operation of the cam 37 by the handle 35 described above.

FIG. 3 is a top view showing a part of the fusing device 1 in which a part of the pressing mechanism 5 is shown in cross section. In FIG. 3, the cam 37, the handle shaft 36, and a part of the cam casing 33 described above are illustrated. Positioning rods 39 and 4 penetrate through each side wall of the cam casing 33.
0s are arranged respectively. Positioning rods 39 and 40
Are movably held in their longitudinal direction by guide sleeves 41 and 42 formed so as to project from the respective side walls of the cam casing 33. A positioning rod 39 is provided in each of the guide sleeves 41 and 42.
Around the circumferences of and 40, compression bars 43 and 44, for example on the coils, are arranged. Compression spring 43
One end of each of 44 and 44 abuts on a head portion 45 and 46 to be a cam follower formed at one end of each of positioning rods 39 and 40, respectively. The other ends of the compression springs 43 and 44 abut the end walls 47 and 48 of the guide sleeves 41 and 42, respectively. Therefore, by the action of the compression springs 43 and 44, the positioning rods 39 and 40 are displaced in the directions of the arrows 49 and 50, respectively, but the end of such displacement is the flange formed on the positioning rods 39 and 40. 51 and 52
Are defined by abutting end walls 47 and 48, respectively.

The heads 45 and 46 of the positioning rods 39 and 40 described above are provided with inclined surfaces 53 and 54 which are contact surfaces with the cam 37. Therefore, as described above, when the handle 35 is rotated so as to face upward, and thereby the cam 37 is rotated, as shown by the phantom line in FIG. 3, each side surface of the cam 37 has an inclined surface 53.
Acting on each of the positioning rods 39 and 4
0 is displaced in the directions of arrows 55 and 56 against the elasticity of the compression springs 43 and 44, respectively.

As shown in FIGS. 1 and 3, the one slide bar 11 is provided with first and second positioning holes 57 and 58, the positions of which are different from each other. First and second positioning holes 59 and 60 are also provided at the corresponding positions of the other slide bar 12. Therefore, when in the state as shown in FIG.
And 40 are displaced in the directions of arrows 55 and 56, respectively, these positioning rods 39 and 40 respectively
Each first positioning hole 57 of the slide bars 11 and 12
And 59. As a result, the pressurizing mechanism 5
It is positioned and fixed with respect to the slide bars 11 and 12. Similarly, when the positioning rods 39 and 40 are fitted into the second positioning holes 58 and 60, respectively, the pressing mechanism 5 is positioned and fixed to the slide bars 11 and 12.

As shown in FIG. 1, legs 61 are provided so as to extend below the pressing mechanism 5. A handle 62 is attached to the upper surface of the pressing mechanism 5, a top plate 63 is attached to the handle 62, and a top plate 63 is attached to the top plate 63.
A protrusion 64 protruding upward is provided.

The heater 3 is shown in FIG. 4 in addition to FIG. The heater 3 includes a first heater face 65 and a second heater face 66 that are heated to a predetermined temperature, and these heater faces 65 and 66 are formed on the surfaces of the heater 3 that face each other. As shown in FIG. 4, the outer peripheral wall 8 of the tank 6 is provided with a through hole 67 corresponding to the position where the joint 7 is attached. The through hole 67 has a diameter substantially equal to the tip diameter of the taper formed on the outer peripheral surface of the overhanging portion 21 included in the joint 7 described above,
No taper is given. First heater face 65
Form a convex portion, and have a shape that comes into contact with the inner peripheral surface of the through hole 67 and the peripheral portion thereof. First
The heater face 65 is provided with a taper in the same direction as the overhang 21 of the joint 7 so that the right side portion of the inner peripheral surface of the through hole 67 in FIG. 4 is more melted. The second heater face 66 forms a recess and has a shape that contacts one end of the joint 7, that is, the outer peripheral surface and the end surface of the overhanging portion 21 and the one end surface of the flange 19.

As shown in FIG. 1, a grip 69 is attached to the heater 3 via a shaft 68. The shaft 68 has a cross-sectional dimension that can be inserted into the groove 18 of the heater receiving plate 17. An engagement plate 70 that engages with the heater receiving plate 17 is attached to the shaft 68. When the engagement plate 70 is engaged with the heater receiving plate 17, the central axis of the heater 3 is made to coincide with the central axis of the joint 7 held by the holder 4.

The temperature of the first and second heater faces 65 and 66 of the heater 3 is regulated by the temperature regulator 71 and kept constant.

Next, a method of attaching the polyethylene joint 7 to the outer peripheral wall 8 of the polyethylene tank 6 using the fusion bonding apparatus 1 as described above will be described.

First, the vacuum pad 2 is adsorbed and fixed to a desired position on the outer peripheral wall 8 of the tank 6. At this time, the center of the through hole 10 provided in the vacuum pad 2 corresponds to the position of the joint 7 to be attached. Providing the through hole 67 in the outer peripheral wall 8 may be performed before or after fixing the vacuum pad 2 on the outer peripheral wall 8. Vacuum pad 2
When the through hole 67 is formed after fixing the holes, if the through hole 67 is formed while positioning the drill using the bosses 13 and 14 of the vacuum pad 2, the vacuum of the through hole 67 It is easy to make the relative position to the pad 2 constant. It is preferable that the inner peripheral surface of the through hole 67 and its peripheral portion are processed to be as flat as possible to remove foreign matter.

Next, the tip portions of the slide bars 11 and 12 are inserted into the bosses 13 and 14, respectively, and then the set bolts 15 and 16 are tightened.

Next, the joint 7 is fixed to the holder 4 by the set bolt 25. On the other hand, the heater 3 is
The temperature of the heater 3 is raised in advance, and the heater 3 is held by the heater receiving plate 17 via the engaging plate 70.

Next, the pressurizing mechanism 5 together with the holder 4 holding the joint 7 is pushed through the handle 35 so as to slide along the slide bars 11 and 12 in the direction approaching the tank 6. In the middle of such an operation,
The protrusion 64 held by the pressurizing mechanism 5 enters into the groove 18 of the heater receiving plate 17 and pushes the engaging plate 70 so that the heater 3 also moves toward the tank 6 as the pressurizing mechanism 5 moves. Be moved.

At the end of the above operation, as shown in FIG. 4, the first heater face 65 of the heater 3 contacts the outer peripheral wall 8 of the tank 6 and the second heater face 6 is in contact.
A state in which 6 contacts the end of the joint 7 is obtained. At this time, as shown in FIG. 3, the positioning rods 39 and 40 extending laterally from the pressurizing mechanism 5 are respectively attached to the slide bar 1.
1 and 12 first locating holes 57 and 59, respectively
It is brought to a position aligned with.

In the above-mentioned state, the handle 35 is
It is rotated about 90 degrees. As a result, the cam 37 is rotated, and the positioning rods 39 and 40 are displaced in the directions of the arrows 55 and 56, respectively, as shown by the phantom lines in FIG. Mating. In this way, the pressing mechanism 5
It is fixed to the slide bars 11 and 12.

At the same time, the cam 37 rotated as described above.
Also acts on the connecting shaft 28 to displace the connecting shaft 28 in the direction of the arrow 32 against the elasticity of the compression spring 27, as shown by the phantom line in FIG. Due to this reaction force, for example, a pressing force of about 65 kg / cm ² is applied to the joint 7
To the tank 6. FIG. 4 shows a state in which such a pressing force is applied.

In the state shown in FIG. 4, the first of the heater 3 is
The second heater faces 65 and 66 are set to a temperature of 270 ° C., for example, and this state is maintained for about 60 seconds. A buzzer or the like set by a timer may be used to notify the end of the holding time.

In the above-mentioned state, the first of the tank 6
Of the heater face 65 and the joint 7
Of the second heater face 66 is heated and melted together. At this time, due to the action of the taper applied to the first heater face 65, the through hole 67
4 is melted more in the right side portion in FIG.

When the above operation is completed, the handle 35 is returned to the original horizontal state. As a result, the positioning rod 3
9 and 40 escape from the first positioning holes 57 and 59, respectively, and the pressing force of the compression spring 27 is removed. Next, the pressing mechanism 5 is separated from the tank 6 along the slide bars 11 and 12 together with the holder 4 holding the joint 7. Then, the heater 3 is removed from the heater receiving plate 17 and placed in another place. In addition, it is preferable to perform the above-mentioned operation promptly.

As described above, after removing the heater 3,
Immediately again, by pushing the handle 35 toward the tank 6 again, the pressurizing mechanism 5 is slid along the slide bars 11 and 12 together with the holder 4 holding the joint 7, and the end of the joint 7 becomes Directly on the outer peripheral wall 8,
It is brought into contact. At this time, due to the action of the taper applied to the overhanging portion 21, the overhanging portion 21 smoothly moves through the through hole 6
It is inserted in 7.

In the above state, the pressurizing mechanism 5 is close to the tank 6 by the amount of the removed heater 3, and the positioning rods 39 and 40 protruding from the side of the pressurizing mechanism 5 are
It is brought into a position aligned with the second positioning holes 58 and 60 of the slide bars 11 and 12. In this state, the handle 35 is again rotated upward by about 90 degrees. As a result, the positioning rods 39 and 40 are fitted into the second positioning holes 58 and 60 of the slide bars 11 and 12, respectively, and the pressing mechanism 5 is fixed to the slide bars 11 and 12.

At the same time, according to the operation of the cam 37, the connecting shaft 28 is displaced in the direction of the arrow 32 against the elasticity of the compression spring 27, as shown by the phantom line in FIG. This state is shown in FIG.

With reference to FIG. 5, the reaction force of the compression spring 27 causes the joint 7 to move toward the tank 6, for example, about 65 k.
It is pressed by a pressing force of g / cm ² . As a result, the polyethylene on the tank 6 side and the polyethylene on the joint 7 side are fused and substantially integrated with each other. That is, the inner peripheral surface of the through hole 67 on the tank 6 side and its peripheral edge, the outer peripheral surface of the overhang 21 on the joint 7 side, and the flange 19 are formed.
And the end faces thereof are fused together to form a substantially integral joint 72.

The above-mentioned state is maintained for 60 seconds or longer, for example. Whether or not the proper fusion is achieved can be confirmed by, for example, whether or not the beads 73 are generated from the entire circumference of the joining portion 72.

When the fusion bonding is completed, the handle 35 is returned to the original horizontal state again. As a result, the positioning rods 39 and 40 are released from the second positioning holes 58 and 60, respectively, and the pressing force of the compression spring 27 is removed. In this state, the joint portion 72 is cooled for about 10 minutes, for example.

After confirming the solidification of the joint portion 72, the joint 7
The set bolt 25 fixing the to the holder 4 is removed. Then, by pulling the handle 35, the holder 4
At the same time, the pressurizing mechanism 5 causes the slide bars 11 and 12 to move.
Is slid along and is separated from the tank 6 and the joint 7. Then, the switch 9 of the vacuum pad 2 is turned off,
The suction force of the vacuum pad 2 is removed. As a result, the vacuum pad 2 is separated from the tank 6 and the holder 4
The vacuum pad 2 is removed together with the pressurizing mechanism 5. At this time, the vacuum pad 2 is prevented from hitting the joint 7.

FIG. 6 shows the tank 6 after the above operation is completed.
The state where the joint 7 is attached is shown. The polyethylene on the side of the joint 7 is fused with the polyethylene on the side of the tank 6 at the joint portion 72, thus achieving a firm mounting state. In the experiment conducted to confirm the strength of the joint portion 72, when the joint 7 was pulled at a predetermined speed so as to be separated from the tank 6, no fracture occurred at the joint portion 72 and the outer peripheral wall 8 of the tank 6 It was confirmed that the reliability of the strength of the joint portion 72 was high.

The above-described embodiment is only a preferred example for carrying out the present invention. For example, the heating temperature and holding time by the heater, the pressing force exerted on the joint portion at the time of fusion, and the like are used. Type of plastic resin,
It depends on the shape on each side of the tank and the joint, the area to be fused, etc., and these may be determined in consideration of the strength after fusion.

[Brief description of drawings]

FIG. 1 is a perspective view showing an entire fusing apparatus 1 for carrying out an embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view showing a holder 4 and a pressure mechanism 5 included in the fusion bonding device 1 shown in FIG.

FIG. 3 is a pressurizing mechanism 5 included in the fusion bonding apparatus 1 shown in FIG.
3 is a top view showing the relationship between the slide bars 11 and 12 and is shown in a partial cross section. FIG.

FIG. 4 is an enlarged cross-sectional view showing a state in which a fusing step by a heater 3 is being performed using the fusing device 1 shown in FIG.

5 is an enlarged cross-sectional view showing a state in which a fusion step is being performed using the fusion device 1 shown in FIG.

FIG. 6 is an enlarged cross-sectional view showing a state in which a joint 7 is attached to the tank 6.

[Explanation of symbols]

 1 Fusing Device 2 Vacuum Pad 3 Heater 4 Holder 5 Pressurizing Mechanism 6 Tank (Container) 7 Joint 19,20 Flange 21 Overhang 27 Compression Spring 28 Connecting Shaft 35 Handle 37 Cam 39,40 Positioning Rod 57,59 1st Positioning hole 58, 60 Second positioning hole 65, 66 Heater face 72 Joint part

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area B29L 23:00

Claims (2)

[Claims] 1. A container made of a thermoplastic resin is prepared, and the container is made of a thermoplastic resin that can be heat-sealed to the thermoplastic resin, and a flange and a projecting portion further projecting from the flange are provided at one end thereof. A joint is provided, in which a tapered taper is provided on the outer peripheral surface of the bulging portion, and the joint has a diameter substantially equal to the tip diameter of the taper of the bulging portion at a desired position of the container. A through hole not provided with a taper is provided, the peripheral portion of the through hole is heated and melted by a heater face having a taper in the same direction as the taper of the overhang portion, and the joint is in contact with the peripheral portion of the through hole. The end portion of is melted by heating, while positioning the protruding portion in the molten through hole,
The end of the melted joint is pressed toward the peripheral edge of the through hole, whereby the container-side thermoplastic resin and the joint-side thermoplastic resin are fused to each other, and then the fusion is performed. A method for mounting a joint on a thermoplastic resin container, comprising the steps of cooling the joint between the container and the joint. 2. A joint, which is attached to a through hole provided in a thermoplastic resin container by heat fusion, and is made of thermoplastic resin, and has a flange and the flange at an end to be heat fused with the container. A joint that is further provided with a protruding portion, and the outer peripheral surface of the protruding portion is tapered.