JP2010120224A - Method for manufacturing jointed sheet - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a jointed sheet which provides a jointed sheet with superimposition tabs and other parts made practically flat and enables continuous jointing even in cases where a sheet to be jointed is thick. <P>SOLUTION: The method for manufacturing the jointed sheet includes a temporary jointing process of superimposing individual ends of two thermoplastic resin sheets and fixing the superimposed parts temporarily, without melting entirely, so as to keep the superimposed state, and the heating/welding process of welding the superimposed parts entirely by heating/melting and rolling pressurization. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a sheet joined body obtained by welding and joining two thermoplastic resin sheets at end portions. In particular, the present invention relates to a method for producing a sheet joined body suitable for a thick sheet joined body such as a waterproof sheet and a water shielding sheet.

Since there are certain restrictions on the width and length of the original sheet, it is necessary to join the sheets in various situations.
Conventionally, welding of a water shielding sheet or the like has been performed by stacking the ends of two sheets to be joined, heating and melting the joining surfaces with a heat source such as a hot iron, hot air iron, hot air, etc. (Patent Documents 1 and 2).
On the other hand, a method has been proposed in which end portions of two sheets to be joined are overlapped and the entire overlapped portion is sandwiched by a heating plate at one time and heat-welded (Patent Document 3).
There has also been proposed a hot plate type continuous welding apparatus in which the end portions of two sheets to be joined are overlapped and run so that the overlapped portion passes between a pair of heating bodies (Patent Document 4).
International Publication No. 02/060675 Pamphlet JP 2001-12612 A Japanese Patent No. 2608856 JP-A-6-883

However, when the joining surfaces are heated and melted as in Patent Documents 1 and 2 above, the overlapped portion (overlap allowance) is twice as thick as the base material sheet, and the overlap allowance portion and the other portions. There was a step between the two. Therefore, there are the following problems.
(1) The shear tensile rupture strength of the stepped portion is reduced to about 30 to 70% of the shear tensile rupture strength of the base material itself, although it depends on the material and thickness of the base material sheet.
(2) The flow of water is obstructed by the step portion.
(3) When another sheet is welded again, a smoothing process is required, such as scraping off the overlap margin with a knife.
(4) It becomes difficult to wind in a roll shape.
In addition, since the joining is performed by melting only the joining surface, it is necessary to increase the welding width or to weld with a double wire so that the air can be checked. Therefore, the width of the stacking margin has to be taken large, and usually a stacking margin of 50 to 100 mm is necessary. Therefore, the loss of the sheet | seat by joining is large and it was disadvantageous also in cost.

On the other hand, according to the inventions of Patent Documents 3 and 4, since the entire overlap margin portion is melted, the step between the overlap margin portion and the other portions can be substantially eliminated and flattened. It is.
However, in Patent Document 3, the entire overlapped portion must be sandwiched with a heating plate at one time, and the sheet cannot be run and continuously processed. Therefore, it could not be used for wide processing of a long sheet.

Moreover, although the apparatus of patent document 4 can run a sheet | seat and can perform a joining process continuously, when the present inventors confirmed, it was used only for joining of a thin sheet | seat.
That is, when thick sheets are joined with the apparatus of Patent Document 4, the melted sheet material is pushed to the side, so that a force acts in the direction of opening the stacking margin (the direction in which the two sheets are moved away from both sides). As the sheet travels, the molten sheet material stays behind, so the force to open the stacking margin increases. For this reason, as the sheet travels, the overlap margin increases, the sheet travels in an oblique direction, and normal joining cannot be performed.

  The present invention has been made in view of the above circumstances, and a sheet joined body in which the overlap allowance and other portions are substantially flattened is obtained, and the sheet to be joined is thick. The manufacturing method of the sheet | seat joined body which can be continuously joined is provided.

In order to achieve the above object, the present invention employs the following configuration.
[1] Temporary joining step of obtaining a temporary joined body by superimposing each end of two thermoplastic resin sheets and temporarily fastening them so as to maintain the superposed state without melting the whole superposed part. When,
The manufacturing method of a sheet | seat joined body provided with the heat welding process which heat-melts and rolls and compresses the whole said overlapped part.
[2] The method for manufacturing a sheet bonded body according to [1], wherein the step of obtaining the temporary bonded body is a process of melting and bonding only the vicinity of the bonded surface of the overlapped portion.
[3] The method for manufacturing a sheet joined body according to [1] or [2], wherein the temporary joining step is a step of partially welding the overlapped portions in a plane direction.
[4] The heating and welding step is a step of running the temporary joined body in a certain direction so that the overlapped portion passes between a pair of heating bodies. The manufacturing method of the sheet joined body of description.
[5] The heating and welding step is a step of running the temporary joined body in a certain direction so that the overlapped portion sequentially passes between the pair of heating bodies and the pair of cooling bodies. [3] The method for producing a joined sheet according to any one of [3].
[6] The heating welding step is a step of causing the temporary joined body to travel in a certain direction so that the overlapped portion sequentially passes between a pair of heating bodies, a pair of rolling rolls, and a pair of cooling bodies. The method for producing a joined sheet according to any one of [1] to [3].
[7] The method for manufacturing a sheet joined body according to any one of [4] to [6], wherein the temporary joined body is caused to travel by being fed between opposing traveling portions of a pair of endless strips.
[8] The method for manufacturing a sheet joined body according to any one of [1] to [7], wherein a width of the overlapped portion is 2 to 20 mm.
[9] In [1] to [8], in the heating and welding step, welding is performed such that the maximum thickness of the joined portion is 1.05 to 1.60 times the thickness of the thermoplastic resin sheet. The manufacturing method of the sheet | seat joined body in any one.
[10] The method for producing a sheet joined body according to any one of [1] to [9], wherein the thickness of the thermoplastic resin sheet is 0.5 mm or more.

  According to the manufacturing method of the present invention, a sheet joined body in which the overlap allowance and the other portions are substantially flattened is obtained, and the joining process is continuously performed even if the sheets to be joined are thick. it can.

  The production method of the present invention is a method for producing a sheet joined body comprising a thermoplastic resin sheet. In the production method of the present invention, the end portions of the two thermoplastic resin sheets are overlapped and temporarily fastened so as to maintain the overlapped state (hereinafter referred to as “temporary joining step”). ) And a step of welding the whole overlapped portion by heating and melting and rolling (hereinafter referred to as a “heating welding step”).

[Thermoplastic resin sheet]
Examples of thermoplastic resin sheets (base materials) to be joined include polyvinyl chloride, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyvinyl acetate, polyester, and the like used for waterproof sheets, waterproof sheets, etc. Examples thereof include various thermoplastic resin sheets such as polytetrafluoroethylene, polyethylene terephthalate, and polystyrene.
Although there is no restriction | limiting in the thickness of a thermoplastic resin sheet, It is preferable that it is a thick thermoplastic resin sheet from the point which show | plays the effect of this invention notably. Specifically, it is preferably 0.5 mm or more, and more preferably 0.8 mm or more. Moreover, it is preferable that it is 2.0 mm or less from the track record of the sheet thickness generally used well as a resin sheet, and it is more preferable that it is 1.5 mm or less. The thicknesses of the two thermoplastic resin sheets are preferably substantially the same, and more preferably the same.
Although there is no restriction | limiting in the length and width | variety of a thermoplastic resin sheet, It is preferable that it is a long sheet | seat from the point which show | plays the effect of this invention notably.

[Temporary joining process]
The temporary bonding step is a step of obtaining a temporary bonded body by stacking the end portions of the two thermoplastic resin sheets and temporarily fixing the stacked states so as to maintain the stacked state.
According to the present invention, in the heating and welding step, which is the next step, the entire overlapped portion (stacking margin) of the two thermoplastic resin sheets is heated and melted and welded. Can be narrowed.
If the overlap width is too small, reliable joining becomes difficult. However, if the width of the stacking margin is too large, the amount of the sheet material melted in the heat-welding process will be excessively protruded from the stacking margin due to pressurization, which may cause the opening of the stacking margin or prevent flattening. Absent. Therefore, the overlap width is preferably 2 to 20 mm, and more preferably 4 to 10 mm.

Temporary fastening can be employed by any method as long as the positional relationship in which the overlapping allowances can be maintained in the “heating welding step” that is the next step. However, unlike the next step, it should not be a joining method that melts the entire stacking allowance. For example, a method of melting and bonding only the vicinity of the joining surface of the overlap allowance, a method of partially welding the overlap allowance in the form of dots, and a method by sewing can be mentioned.
Examples of the method of melting and bonding only the vicinity of the joining surface of the overlap allowance include a method in which the joining surface is heated and melted with a hot iron, hot air iron, hot air, etc., and then pressed from both sides.
Moreover, as a method of performing partial welding of the overlap margin in the surface direction, a method of performing partial welding in a dot shape using an ultrasonic welding machine, a high frequency welding machine, or the like can be given.
In the case of sewing, it is preferable to use a heat-resistant fiber yarn such as super aramid fiber (Kevlar sewing yarn manufactured by Toray DuPont, etc.) as a sewing yarn.

[Heat welding process]
The heat welding step is a step of welding by heating and melting and rolling the entire stacking allowance. In the present invention, the entire stacking allowance is heated and melted and welded, whereby a part of the melted stacking allowance sheet material can be pushed out to both sides of the overlap allowance. Therefore, it is possible to make the thickness of the overlap margin substantially equal to the thickness of the other portions, and flattening can be achieved. In addition, reliable bonding is possible even when the overlap margin is narrow.
In the heat welding process, a force in the direction of opening the stacking margin (direction of moving the two sheets away) works by pushing the sheet material of the stacking margin to both sides of the stacking margin. However, in the present invention, the provisional fastening allows the joining margin to be maintained and the two sheets to be joined while maintaining the positional relationship.

In the heat welding step, it is preferable to melt the entire overlap allowance so that the overlap allowance relatively passes between the pair of heating bodies.
The width of the heating element is at least equal to or larger than the width of the stacking allowance in order to melt the entire overlap allowance. Moreover, it is preferable that it is 2 times or more of the width | variety of overlap, and it is more preferable that it is 5 times or more. Heating including both sides of the stacking allowance is preferable because a part of the molten sheet material for the stacking allowance can be brought into close contact with the base material on both sides of the stacking allowance.
On the other hand, the width of the heating body is preferably 20 times or less, and more preferably 10 times or less the width of the stacking allowance. This is because if the width of the heating body is too wide, the strength in the vicinity of the overlap is insufficient, and it becomes difficult to run the entire temporary joined body. Further, excessive heating energy is consumed, which is not preferable.

  When the overlap allowance passes relatively between the pair of heating bodies, it is necessary to run either the temporary joined body or the pair of heating bodies, but it is suitable for joining long sheets. Therefore, it is preferable to run the temporary joined body. That is, it is preferable that the temporary joined body travels in a certain direction so that the overlap margin passes between the pair of heating bodies. As a result, the entire overlap allowance can be melted and joined. As the heating source, a hot plate hot plate, hot air, or the like can be used.

The overlap allowance is preferably passed between the pair of cooling bodies after passing between the pair of heating bodies. Thereby, after joining, the molten state can be eliminated at an early stage, and the strength of the stacking allowance can be recovered. As the cooling source, a water-cooled type, a cold air, or the like can be adopted.
The width of the cooling body is at least the width of the heating body in order to cool the melted portion. Moreover, it is preferable that it is 1 time or more of the width | variety of a heating body, and it is more preferable that it is 1.3 times or more. It is preferable to make the width wider than the width of the heating body because all the parts warmed by the heating body are cooled, and as a result, the cooling efficiency is improved.
On the other hand, the width of the cooling body is preferably not more than twice the width of the heating body, and more preferably not more than 1.6 times. This is because if the width of the cooling body is too wide, the width of the entire machine becomes wide. Further, excessive cooling energy is consumed, which is not preferable.

In addition, the molten stacking allowance can be joined by the pressure when sandwiched between a pair of heating bodies, but in order to join more reliably, after passing the heating body, the cooling body Before passing, it is preferable to pass between a pair of rolling rolls and pressurize with a rolling roll.
In this case, the width of the rolling roll is at least equal to or greater than the width of the stacking margin in order to roll the entire stacking margin. Moreover, it is preferable that it is 2 times or more of the width | variety of overlap, and it is more preferable that it is 5 times or more. It is preferable to roll the sheet including both sides of the stacking allowance because a part of the molten sheet material of the stacking allowance can be brought into close contact with the base material on both sides of the stacking allowance.
On the other hand, the width of the rolling roll is preferably 20 times or less, and more preferably 10 times or less, the width of the stacking allowance. This is because if the width of the rolling roll is too wide, the width of the entire machine becomes wide.

Moreover, it is preferable that the temporary joined body is caused to travel by being fed between the traveling portions facing each other of the pair of endless belts. That is, it is preferable that the pair of heating bodies, rolling rolls, and cooling bodies sandwich a temporary joined body that travels via an endless belt-like body.
The temporary joined body can be driven by a pair of rotating roller groups.

The heating temperature is a temperature exceeding the melting point of the material of the thermoplastic resin sheet.
The pressure at the time of pressurization is preferably adjusted so that the maximum thickness of the joined portion is 1.05 times or more the thickness of the thermoplastic sheet as the base material. If the ratio is less than 1.05 times, the molten resin in the overlap margin portion must be extruded not only on both sides but also in the traveling direction. For this reason, the molten resin gradually accumulates in the rolling roller portion, which tends to hinder the welding operation. The maximum thickness is more preferably 1.1 times or more, and further preferably 1.2 times or more.
On the other hand, the maximum thickness of the joined portion is preferably close to 1.0 times from the viewpoint of improving flatness. Therefore, the maximum thickness of the joined portion is preferably 1.60 times or less, and more preferably 1.45 times or less.
Specific welding conditions such as heating temperature, heating time, cooling temperature, cooling time, pressure, and pressurization time are appropriately set depending on the material, thickness, and the like of the thermoplastic resin sheet. Even if the material, thickness, etc. of the thermoplastic resin sheet are the same, these conditions are related to each other and are not uniquely determined. For example, if the heating temperature is high, the pressurization time tends to be short (the traveling speed of the temporary joined body should be high). Further, if the heating temperature is high, the pressure during pressurization tends to be low.

In the case where another sheet is laminated on the thermoplastic resin sheet, the heat-welding step is performed after the other sheet that overlaps the stacking margin is rolled in advance.
For example, as in the case of the water shielding sheet described in Japanese Patent No. 4036100, when a buffer sheet made of a nonwoven fabric is laminated on the thermoplastic resin sheet, the buffer sheet of the portion overlapping the stacking margin is rolled up, A heat welding process is performed so that it may not be pinched | interposed between a heating body, a rolling roller, and a cooling body.

The heat welding step can be performed using, for example, an open arm type hot plate type continuous welding machine LHP-W708-OA type manufactured by Quinlight Electronics Seiko Co., Ltd.
In this welding apparatus, as shown in FIG. 1, an endless belt-like body 2A is attached to a machine base 1 via a plurality of rolls 3A, and the endless belt-like body 2A travels horizontally in the arrow X direction. A traveling portion 21A and a backward traveling portion 22A that travels in the direction opposite to the arrow X direction are formed. Further, an endless belt 2B is attached to a mounting frame 5 attached to the machine base 1 via a support shaft 4 via a plurality of rolls 3B, and the endless belt 2B travels horizontally in the direction of the arrow X. The forward traveling portion 21B and the backward traveling portion 22B traveling in the direction opposite to the arrow X direction are formed. The mounting frame 5 can swing up and down between the horizontal posture shown by the solid line in FIG. 1 and the inclined posture shown by the phantom line with the support shaft 4 as the center. In the state in which the mounting frame 5 is in the horizontal posture, the forward travel portion 21A of the endless strip 2A disposed on the lower side and the endless strip 2B disposed on the upper side opposite thereto are arranged. The feed path 6 of the temporary joined body S is formed between the forward travel part 21B.

  Two heating units 71A, 72A and a cooling unit 73A are provided on the machine base 1, and two heating units 71B, 72B and a cooling unit 73B are also provided on the mounting frame 5. The heating units (that is, the lower heating units) 71A and 72A on the machine base 1 side are arranged in two stages in front and rear so as to oppose the opposite side surface of the feed path 6 in the forward travel portion 21A of the lower endless belt-like body 2A. In addition, the cooling unit 73A (that is, the lower cooling unit) is provided on the sheet feeding direction side facing the arrow X direction from the installation position of the downstream lower heating unit 72A. The lower cooling unit 73A is opposed to the opposite side surface of the forward travel portion 21A from the feed path 6.

  The heating units (that is, the upper heating units) 71B and 72B on the mounting frame 5 side are arranged in two stages in the front and rear direction so as to oppose the opposite side surfaces of the feed path 6 in the forward travel portion 21B of the upper endless strip 2B. The cooling unit (ie, the upper cooling unit) 73B is provided on the sheet feeding direction side of the installation position of the upper heating unit 72B in the subsequent stage. The upper cooling unit 73B faces the opposite side surface of the forward travel portion 21B from the feed path 6.

  The lower heating units 71A and 72A in the front and rear two stages and the upper heating units 71B and 72B in the front and rear two stages are opposed to each other, and the lower cooling unit 73A and the upper cooling unit 73B are also opposed to each other. Furthermore, a pair of rolling rollers 8B and 8A are provided above and below the feed path 6 between the upper and lower heating units 72B and 72A and the upper and lower cooling units 73B and 73A on the rear side.

Reference numeral 10 denotes an operation panel. By operating this operation panel 10, the set temperatures of the upper and lower heating units 71B and 71A and the upper and lower heating units 72B and 72A can be independently adjusted. It is possible to adjust the traveling speed of the endless strips 2A and 2B.
Reference numeral 91 denotes a guide roller for feeding the temporarily joined body S, and 92 and 93 denote guide rollers for feeding the temporarily joined body S.

  When the apparatus of FIG. 1 is used, when the temporary joined body S is fed into the feed path 6 through the guide roller 91, the temporary joined body S moves along the feed path 6 at the same speed as the upper and lower endless strips 2A and 2B travel. It is sent in the X direction, and the temporary bonded body S is heated by the upper and lower heating units 71A and 71B, followed by the heating by the upper and lower heating units 72A and 72B. In this case, the temporary joined body S is heated through the forward traveling portions 21A and 21B of the upper and lower endless strips 2A and 2B.

  After pressure is applied to the temporary bonded body S that has passed through the heating zone by the upper and lower rolling rolls 8A and 8B, cooling is performed by the upper and lower cooling units 73B and 73A. Further, the forward traveling portions 21A and 21B of the endless strips 2A and 2B are cooled by the upper and lower cooling units 73A and 73B after passing through the heating regions of the heating units 71A, 71B, 72A and 72B.

[Inspection method]
According to the present invention, it is possible to obtain a sheet joined body that is securely joined even if it is a thick sheet or a long welding distance.
As the quality control of the sheet joined body obtained by the present invention, it is preferable to confirm that there are no holes (pinholes) and that there are no portions that are significantly thinner than the base material.
Specific inspection methods include a method using a high-voltage pinhole tester, a method in which strong light is applied from the back surface and the transmitted light is turned into an angle, and the thickness near the overlap margin is continuously measured with an ultrasonic thickness measuring instrument. It is possible to adopt a method for measuring the temperature.

  The present invention will be specifically described below with reference to examples. Of course, the present invention is not limited to these examples.

[Example 1]
Two end portions of an ethylene-vinyl acetate copolymer sheet having an average thickness of 0.82 mm ("NATM tunnel water-stop sheet", hereinafter referred to as EVA sheet manufactured by CI Kasei Co., Ltd.) are overlapped with a width of 5 mm. A temporary joined body was obtained by repeatedly applying a hot air of 350 ° C. and welding of a 50 mm-long welded portion at a pitch of 20 mm with a triac type manual hot air type welder manufactured by Leister.

Next, this temporary joined body was heat-welded with an open arm type hot plate type continuous welding machine LHP-W708-OA type manufactured by Quinn Light Electronics Co., Ltd. in FIG. 1 to obtain a sheet joined body. Specific specifications of each unit of the welder are as follows.
The heating units 71A and 71B have a width of 20 mm and a length of 400 mm.
The heating units 72A and 72B have a width of 30 mm and a length of 400 mm.
The cooling units 73A and 73B have a width of 40 mm and a length of 400 mm.
The rolling rolls 8A and 8B are made of synthetic rubber and have a width of 40 mm.
Endless strips 2A and 2B are made of polytetrafluoroethylene and have a width of 40 mm.

  The temperatures of the heating units 71A, 72A, 71B, 72B were all 190 ° C., and the temperatures of the cooling units 73A, 73B were all 10 ° C. The pressing of the rolling roll was 0.6 MPa, and the line speed was 3.0 m / min.

About three obtained samples, as shown in FIG. 2, the thickness of five places of ae was measured along the width direction. c is the center of the overlap margin, b and d are positions 5 mm from c, and a and e are positions 10 mm from c. Moreover, about the EVA sheet | seat which is not joined as each sample and a blank, a 2 dumbbell is cut out according to JISK6773, and the part containing ae of FIG. 2 or FIG. A test was conducted. The results are shown in Table 1.
As shown in Table 1, the welded part was joined without a distortion and with a maximum thickness of 1.15 mm (1.4 times that of the blank). The ratio of the tensile strength of the sample of Example 1 to the blank tensile strength (residual rate) was 88%, and similarly, the ratio of the elongation of the sample of Example 1 to the blank elongation (residual rate) was 96%. .

[Example 2]
A temporary joined body was obtained in the same manner as in Example 1 except that the overlap margin width was 10 mm. Next, the temperature of the heating units 71A, 72A, 71B, 72B is 200 ° C., the temperature of the cooling units 73A, 73B is 5 ° C., the pressure of the rolling roll is 0.6 MPa, and the line speed is 2.5 m / min. Obtained a sheet joined body in the same manner as in Example 1.
About the obtained three samples, the thickness of five places ae shown in FIG. A tensile test was performed in the same manner as in Example 1. The results are shown in Table 1.
As shown in Table 1, the welded portion was joined without a distortion and with a maximum thickness of 1.08 mm (1.32 times that of the blank). The ratio of the tensile strength of the sample of Example 2 to the blank tensile strength (residual ratio) was 93%, and similarly the ratio of the elongation of the sample of Example 1 to the blank elongation (residual ratio) was 97%. .

[Comparative Example 1]
A sheet joined body was made in the same manner as in Example 1 except that the temporary joining was not made and the overlap margin was 5 mm and was heat-welded with an open arm type hot plate type continuous welding machine manufactured by Quinlight Electronics Co., Ltd. Got.
The welded portion was joined with a maximum thickness of 1.05 mm, but the welded portion spread toward the welded direction, and the sheet joined body was bent at the welded portion.

[Comparative Example 2]
The ends of the EVA sheet used in Example 1 were overlapped with an overlap margin width of 140 mm. For this stacking allowance, two 15mm wide welds (central unwelded part width of 15mm) were applied at a hot air temperature of 400 ° C with a Tween T-type self-propelled hot air soldering type welding machine manufactured by Leister. A sheet joined body was obtained. The welding part was joined as shown in FIG.
About three obtained samples, as shown in FIG. 3, the thickness of five places of ae was measured along the width direction. c is the center of the overlap margin, b and d are positions 5 mm from c, and a and e are positions 10 mm from c. A tensile test was performed in the same manner as in Example 1. The results are shown in Table 1.
As shown in Table 1, the ratio of the tensile strength of the sample of Comparative Example 2 to the blank tensile strength (residual rate) was 40%, and similarly the ratio of the elongation of the sample of Comparative Example 2 to the elongation of the blank (residual rate). ) Was 50%.
This is presumed to be a low value because there are two points where the thickness is sharply changed, and stress is concentrated at one of the two points to cut.

[Example 3]
The two end portions of a polyvinyl chloride sheet having an average thickness of 1.53 mm ("Binon civil engineering sheet", hereinafter referred to as a PVC sheet, manufactured by C-I Kasei Co., Ltd.) are stacked with an overlap width of 5 mm. Similarly, a temporary joined body was obtained.
Next, the temperature of the heating units 71A, 72A, 71B, 72B is 270 ° C., the temperature of the cooling units 73A, 73B is 5 ° C., the pressure of the rolling roll is 0.6 MPa, and the line speed is 3.3 m / min. Obtained a sheet joined body in the same manner as in Example 1.
About the obtained three samples, the thickness of five places ae shown in FIG. Moreover, the tensile test was done like Example 1 about the obtained three samples and the PVC sheet | seat which is not joined as a blank. The results are shown in Table 2.
As shown in Table 2, the welded part was joined without a distortion and with a maximum thickness of 1.9 mm (1.27 times that of the blank). The ratio of the tensile strength of the sample of Example 3 to the blank tensile strength (residual ratio) was 88%, and similarly the ratio of the elongation of the sample of Example 3 to the blank elongation (residual ratio) was 89%. .

[Comparative Example 3]
The edge part of the PVC sheet used in Example 3 was overlapped with an overlap margin width of 140 mm. For this stacking allowance, two 15mm wide welds (center unwelded part width of 15mm) are applied at a hot air temperature of 460 ° C with a Leister Tween T-type self-propelled hot air soldering type welding machine, A sheet joined body was obtained. The welding part was joined as shown in FIG.
About the obtained three samples, the thickness of five places of ae shown in FIG. A tensile test was performed in the same manner as in Example 1. The results are shown in Table 2.
As shown in Table 2, the ratio of the tensile strength of the sample of Comparative Example 3 to the blank tensile strength (residual rate) was 59%, and similarly the ratio of the elongation of the sample of Comparative Example 3 to the elongation of the blank (residual rate). ) Was 51%.
This is presumed to be a low value because there are two points where the thickness is sharply changed, and stress is concentrated at one of the two points to cut.

[Example 4]
Two end portions of a linear low density polyethylene sheet having an average thickness of 1.55 mm (CAI Kasei Co., Ltd., “metallobarrier”, hereinafter referred to as LLDPE sheet) are stacked 5 mm in the same manner as in Example 1. A temporary joined body was obtained.
Next, the temperature of the heating units 71A, 72A, 71B, 72B is 250 ° C., the temperature of the cooling units 73A, 73B is 5 ° C., the pressure of the rolling roll is 0.6 MPa, and the line speed is 2.0 m / min. Obtained a sheet joined body in the same manner as in Example 1.
About three obtained samples, it carried out similarly to Example 1, and measured the thickness of five places of ae. Moreover, the tensile test was done like Example 1 about the obtained 3 samples and the LLDPE sheet | seat which is not joined as a blank. The results are shown in Table 3.
As shown in Table 3, the welded portion was joined without a distortion and with a maximum thickness of 1.75 mm (1.13 times that of the blank). The ratio of the tensile strength of the sample of Example 3 to the blank tensile strength (residual rate) was 83%, and similarly the ratio of the elongation of the sample of Example 3 to the blank elongation (residual rate) was 99%. .

[Comparative Example 4]
The end portion of the LLDPE sheet used in Example 4 was made into a stacking allowance width of 140 mm, and two pieces of 15 mm width were welded at a hot air temperature of 500 ° C. with a twine-T type self-propelled hot air soldering type welding machine manufactured by Leister. A center unwelded portion width 15 mm) was applied to obtain a sheet joined body. The welding part was joined as shown in FIG.
About the obtained three samples, the thickness of five places of ae shown in FIG. A tensile test was performed in the same manner as in Example 1. The results are shown in Table 3.
As shown in Table 3, the ratio of the tensile strength of the sample of Comparative Example 4 to the blank tensile strength (residual rate) was 34%, and similarly the ratio of the elongation of the sample of Comparative Example 4 to the elongation of the blank (residual rate). ) Was 49%.
This is presumed to be a low value because there are two points where the thickness is sharply changed, and stress is concentrated at one of the two points to cut.

  The sheet assembly obtained by the present invention is, for example, a general / industrial waste landfill, a muddy water sedimentation basin, or a factory waste liquid treatment basin. Sludge pond, agricultural reservoir, residential land development pond, golf course, garden, park and other ornamental ponds, agricultural and industrial waterways, drainage channels, box tunnels, buildings, pools, tanks and other underground structures, earth dams Can be used in industrial fields such as rock-fill dams, water-impervious cores such as river dams and reservoir dams, desk mats, truck seats, tent warehouse fabrics, container bags, sheet shutters, sheet partition curtains, screens and blinds.

It is an example of the apparatus for performing the heat welding process of this invention. It is a figure which shows the thickness measurement position of the sample of an Example. It is a figure which shows the thickness measurement position of the sample of a comparative example.

Explanation of symbols

S Temporary joint X Arrow indicating the sheet feed direction 6 Feed paths 2A, 2B Endless strips 8A, 8B Rolling rolls 21A, 21B Forward travel parts 71A, 72A, 71B, 72B Heating units 73A, 73B Cooling units

Claims (10)

A temporary joining step of superimposing each end portion of the two thermoplastic resin sheets, and temporarily fixing so as to maintain the overlapped state without melting the entire overlapped portion;
The manufacturing method of a sheet | seat joined body provided with the heat welding process which heat-melts and rolls and compresses the whole said overlapped part.   The method for producing a sheet joined body according to claim 1, wherein the step of obtaining the temporary joined body is a process of melting and bonding only the vicinity of the joined surface of the overlapped portion.   The manufacturing method of the sheet joined body according to claim 1 or 2, wherein the temporary joining step is a step of partially welding the overlapped portions in a surface direction.   The sheet joined body according to any one of claims 1 to 3, wherein the heat welding step is a step of running the temporary joined body in a certain direction so that the overlapped portion passes between a pair of heating bodies. Manufacturing method. The heating welding step is a step of causing the temporary joined body to travel in a certain direction so that the overlapped portion sequentially passes between a pair of heating bodies and a pair of cooling bodies. A method for producing a sheet joined body according to claim 1.   The heating and welding step is a step of causing the temporary joined body to travel in a certain direction so that the overlapped portion sequentially passes between a pair of heating bodies, a pair of rolling rolls, and a pair of cooling bodies. Item 4. A method for producing a joined sheet according to any one of Items 1 to 3.   The method for manufacturing a sheet joined body according to any one of claims 4 to 6, wherein the temporary joined body is caused to travel by being fed between traveling portions facing each other of a pair of endless belt-like bodies.   The method for producing a sheet joined body according to any one of claims 1 to 7, wherein a width of the overlapped portion is 2 to 20 mm.   In the said heat welding process, it welds so that the maximum thickness of the joined part may be 1.05-1.60 times the thickness of the said thermoplastic resin sheet. Manufacturing method of sheet joined body.   The method for producing a sheet joined body according to any one of claims 1 to 9, wherein a thickness of the thermoplastic resin sheet is 0.5 mm or more.

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