JPWO2019103123A1 - Joined body, its manufacturing method and welding equipment - Google Patents

Abstract

Providing a bonded body with excellent scratch resistance. A bonded body in which at least two raw fabrics made of a thermoplastic resin film are joined, and a surface waviness shape measured at a position 50 mm outward from the outer edge in the width direction of the joint portion that joins adjacent raw fabrics. A joint characterized by having a root mean square height of 0.5 mm or less.

Description

The present invention relates to a bonded body, a method for producing the same, and a welding device.

Thermoplastic resin films are used in various applications such as coating materials for membrane structures and coating materials for agriculture. When the width of the thermoplastic resin film is less than the required width, the ends of the thermoplastic resin film in the width direction are joined to each other and used as a bonded body.
As a method for joining the thermoplastic resin film, a welding method is widely used industrially (for example, Patent Documents 1 to 3). For joining by the welding method, for example, a pair of endless strips in which two thermoplastic resin films are sandwiched and run with their widthwise ends overlapped, and a pair of endless strips are installed facing the running path. This is performed by using a welding device provided with a heating mechanism that heats the overlapping portion of the thermoplastic resin films while pressing the overlapping portion.

Japanese Patent No. 3952020 Japanese Patent No. 4063049 JP-A-2005-212111

Coating materials for membrane structures and agricultural coating materials are often used by being fixed to a frame. However, the conventional bonded body has a problem that the surface is easily scratched by rubbing against the frame or the like during transportation or fixing to the frame. Scratches on the surface of the joint cause poor appearance and reduced yield.

An object of the present invention is to provide a bonded body having excellent scratch resistance.
Another object of the present invention is to provide a method for producing a bonded body capable of suppressing the occurrence of wrinkles when bonding thermoplastic resin films to each other, and a welding device preferably used in the manufacturing method.

The present invention provides a bonded body, a method for producing the same, and a welding device having the following configurations [1] to [15].
[1] A bonded body in which at least two raw fabrics made of a thermoplastic resin film are bonded.
A joint body characterized in that the root mean square height of the surface waviness measured at a position 50 mm outward from the outer edge in the width direction of the joint portion between adjacent raw fabrics is 0.5 mm or less.
[2] The joint of [1] in which the root mean square height of the surface waviness measured at a position 1 mm outward from the outer edge in the width direction of the joint is 0.5 mm or less.
[3] The joint body of [1] or [2] in which the width of the joint portion is 1 to 40 mm.
[4] The bonded body according to any one of [1] to [3], wherein the thermoplastic resin film is a crystalline resin film.
[5] The bonded body according to any one of [1] to [4], wherein the thermoplastic resin film is a fluororesin film.
[6] The fluororesin is an ethylene-tetrafluoroethylene copolymer, perfluoro (alkyl vinyl ether) -tetrafluoroethylene copolymer, hexafluoropropylene-tetrafluoroethylene copolymer, chlorotrifluoroethylene polymer, vinyl fluoride. Dopolymer, vinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-vinylidene The conjugate of [5] which is at least one selected from the group consisting of a fluoride-propylene copolymer, an ethylene-chlorotrifluoroethylene copolymer and a propylene-chlorotrifluoroethylene copolymer.
[7] The bonded body according to any one of [1] to [6], which is a film for a membrane structure.
[8] A bonded body according to any one of [1] to [6], which is an agricultural film.
[9] A pair of endless strips are rotated so that the opposing portions travel forward, and two raw fabrics made of a thermoplastic resin film are overlapped with each other at the widthwise end portions of the raw fabrics. A region to be welded including a portion in which the two raw fabrics are in contact with each other when the pair of endless strips are sandwiched between the outer peripheral surfaces of the opposing portions of the pair of endless strips in a state of being brought into contact with each other. Is a method for producing a bonded body in which the two raw fabrics are welded at least once by heating and pressing the two raw fabrics from both sides and welding the two raw fabrics at least once.
When heating the welding target region, the temperature measured by a thermocouple arranged on the surface of the raw fabric at a position 50 mm outward from the outer edge in the width direction of the welding target region is set to 40 ° C. or less. A method for manufacturing a bonded body.
[10] The manufacturing method of [9], wherein the overlapping width of the two raw fabrics is 0 to 40 mm.
[11] The method for producing [9] or [10], wherein the thermoplastic resin film is a crystalline resin film.
[12] The production method according to any one of [9] to [11], wherein the thermoplastic resin film is a fluororesin film.
[13] At least a pair of hot plate type heating mechanisms are provided in the middle of the traveling path through which the two raw fabrics travel, and the welding target region is heated by the at least pair of hot plate type heating mechanisms, and the hot plate type heating is performed. The production method according to any one of [9] to [12], wherein the first cooling mechanism suppresses heat transfer from the mechanism to a region other than the welding target region of the two raw fabrics.
[14] The manufacturing method of [13], wherein the first cooling mechanism is a water cooling mechanism or an air cooling mechanism.
[15] A pair of endless strips arranged so that the portions facing each other travel forward when rotated, and a pair of welded portions are provided.
Two raw fabrics made of a thermoplastic resin film are brought into contact with each other by overlapping or abutting the widthwise ends of the raw fabrics between the outer peripheral surfaces of the opposite portions of the pair of endless strips. A traveling path is formed so that the traveling path is formed, and the pair of welded portions are arranged at positions inside the pair of endless strips facing the traveling path.
Each of the pair of welded portions includes at least one hot plate type heating mechanism, a first cooling mechanism arranged in the vicinity of the hot plate type heating mechanism, and a pressing roll arranged on the downstream side of the hot plate type heating mechanism. A second cooling mechanism arranged on the downstream side of the pressing roll is provided.
The first cooling mechanism is a welding device provided so as to suppress heat propagation from the hot plate type heating mechanism to a region other than the target region of the two raw fabrics.

The bonded body of the present invention has excellent scratch resistance.
According to the method for producing a bonded body of the present invention, it is possible to suppress the occurrence of wrinkles when bonding thermoplastic resin films to each other.
The welding apparatus of the present invention is suitably used in the method for producing the bonded body.

It is a figure explaining the method of measuring the thickness of the original fabric and the width of the joint part in a joint body. It is a figure explaining the method of measuring the thickness of the original fabric and the width of the joint part in a joint body. It is a figure explaining the calculation method of the root mean square root height (standard deviation in the height direction) of the surface swell shape. It is a schematic block diagram which shows an example of the welding apparatus of this invention. It is a partial cross-sectional view which shows a part of IV-IV cross section of the welding apparatus shown in FIG. It is a schematic block diagram which shows an example of an endless band. How to stack the raw fabrics when the raw fabrics are welded in Example 1, the position and width of heating and pressing (1st time: when heating with the 1st stage heating unit, 2nd time: heating with the 2nd stage heating unit It is a figure explaining time). How to stack the raw fabrics when the raw fabrics are welded in Example 2, the position and width of heating and pressing (1st time: when heating with the 1st stage heating unit, 2nd time: heating with the 2nd stage heating unit It is a figure explaining time). How to stack the raw fabrics when the raw fabrics are welded in Example 3, the position and width of heating and pressing (first time: when heating with the first stage heating unit, second time: heating with the second stage heating unit It is a figure explaining time). How to stack the raw fabrics when the raw fabrics are welded in Example 4, the position and width of heating and pressing (first time: when heating with the first stage heating unit, second time: heating with the second stage heating unit It is a figure explaining time).

The meanings of the following terms in the present specification are as follows.
"Tensile breaking strength" refers to the tensile breaking stress (tensile breaking stress) measured at a test speed of 200 mm / min based on JIS K7127: 1999 for a dumbbell-shaped No. 5 sample specified in JIS K6251: 2010 (ISO 37). MPa). In the measurement of the tensile breaking strength of the joint portion of the joint body, the sample is cut out from the joint body so that the length direction of the sample coincides with the TD of the joint body and the joint portion passes through the central portion in the length direction of the sample. Use the one.
"Melting point" means the temperature corresponding to the maximum value of the melting peak measured by the differential scanning calorimetry (DSC) method.
“Maximum height roughness Rz” refers to ISO4287: 1997, Amd. It is a value measured based on 1: 2009 (JIS B0601: 2001). The reference length rl (cutoff value λc) for the roughness curve when determining the maximum height roughness is 0.8 mm. In addition, in this specification, it may be simply described as "Rz".
The "raw fabric" is a film before post-processing such as welding. The raw fabric may be a long (strip-shaped) film wound into a roll or a sheet-fed film.
The "welding target region" is a region where the raw fabrics are welded to each other during the production of the bonded body, that is, a region where the raw fabrics are heated and pressed.
In the present specification, the flow direction is also referred to as "MD" (Machine Direction), and the direction orthogonal to MD is also referred to as "TD" (Transverse Direction). MD coincides with the length direction of the original fabric. Further, the MD is typically the traveling direction of the original fabric at the time of joining (welding), and is the direction in which the joint portion (original fabric welding portion) extends. The TD typically coincides with the width direction of the original fabric and the width direction of the joint.
The dimensional ratios in FIGS. 1, 2 and 4 to 10 are different from the actual ones for convenience of explanation.

[Joint body]
The bonded body of the present invention is formed by joining at least two raw fabrics made of a thermoplastic resin film, and has a joint portion for joining adjacent raw fabrics.
In the bonded body of the present invention, two or more original fabrics are typically arranged along the width direction, and the ends of adjacent original fabrics in the width direction are joined to each other. It is easy to increase the length of the original fabric, but there is a limit to increasing the width. By arranging two or more raw fabrics in the width direction and joining them, a wide and large area can be obtained.
The number of raw fabrics constituting the bonded body can be appropriately selected according to a desired width, and is not particularly limited, but is, for example, 2 to 10 sheets.

The joint portion is a portion where the ends of two adjacent raw fabrics are in contact with each other and has a thickness of 101% or more with respect to the thickness of the original fabric. The thickness of the joint is typically less than 200%, more preferably 150% or less with respect to the thickness of the original fabric.

The joint portion is typically a welded portion formed by overlapping the widthwise ends of the raw fabrics to be joined with each other and welding the overlapped portions.
In the present invention, since the overlapping portion is pressed from both sides at the time of welding, the thermoplastic resin is melted at the overlapping portion, a part of the melted thermoplastic resin is extruded to the outside of the overlapping portion, and the thickness of the overlapping portion is thin. The nearby part becomes thicker. Therefore, the joint is often formed wider than the overlap.
When the overlapping portion is well stretched to form a joint portion during manufacturing of the joint body, the crystallinity of the joint portion is increased by stretching, and the joint body has sufficient tensile strength even if the width of the joint portion is narrow. Is easy to obtain. Therefore, it is preferable that the thickness of the joint is thin.

The width of the joint is preferably 1 to 40 mm, more preferably 1 to 8 mm, even more preferably 1 to 5 mm, and particularly preferably 1 to 3 mm. If the width of the joint is 40 mm or less, even if the joint shrinks due to heat applied to the joint, the amount of dimensional change of the joint is relatively small because the width of the joint is narrow, and wrinkles (rear). Wrinkles in the process) are less likely to occur. In particular, when it is 8 mm or less, even if the joint portion is scratched during transportation or fixing to the frame, the number of scratches on the joint portion is relatively small because the width of the joint portion is narrow, and the scratches are not noticeable. Therefore, the appearance of the bonded body is unlikely to deteriorate, and the yield is also unlikely to decrease. When the width of the joint is 1 mm or more, the tensile breaking strength of the joint is excellent.

The thickness of the original fabric and the width of the joint in the joint are measured by the following measuring methods.
As shown in FIG. 1, the joint body 1 is cut into a square shape of 20 cm × 20 cm so that the joint portion 1a for joining the adjacent raw fabrics 3 at an arbitrary position of the MD passes through the center of the TD, and the sample 5 To get. The position of the joint portion 1a can be visually confirmed.
The TD cross section was observed with an optical microscope at a position 10 cm inward from one outer edge of the MD of the sample 5, and as shown in FIG. 2, positions b, e and 4 cm 2 cm inward from both outer edges of the TD cross section. The thickness of the sample 5 is measured at the positions c and d (4 locations in total), and the average value thereof is taken as the thickness of the original fabric 3.
A TD cross section was observed with an optical microscope at a position 10 cm inward from one outer edge of the MD of the sample 5, and as shown in FIG. 2, a portion having a thickness of 101% or more with respect to the thickness of the original fabric 3. Request width _{W a} of the (junction 1a). From each one of the outer edge of the MD of the sample 5 toward the other outer edge in the position of 5cm and 15cm above and in the same manner, the width W _a of the portion is thick 101% or more with respect to the thickness of the original fabric 3 Ask for. _Let the average value of those widths Wa be the width of the joint portion 1a.

The tensile breaking strength of the joint portion is preferably 50% or more, more preferably 60% or more, and particularly preferably 80% or more of the tensile breaking strength of the original fabric. When the tensile breaking strength of the joint portion is not more than the upper limit value, the scratch resistance and dimensional stability of the joint portion are more excellent. The upper limit of the tensile breaking strength of the joint is not particularly limited and may be 100%.

The Rz on the surface of the joint is preferably 15 μm or less, more preferably 5 μm or less, further preferably 1 μm or less, and particularly preferably 0.7 μm or less. When Rz is not more than the upper limit value, the scratch resistance of the joint is more excellent.
The smaller the Rz on the surface of the joint, the more preferable, and it may be 0 μm.

The raw fabric is made of a thermoplastic resin film.
The thermoplastic resin film contains a thermoplastic resin.
Examples of the thermoplastic resin include amorphous resins and crystalline resins.
Examples of the amorphous resin include polystyrene, polyvinyl chloride, polycarbonate, polymethyl methacrylate and the like.
Examples of the crystalline resin include fluororesin, polyester resin, and polyolefin resin.

Examples of the fluororesin include ethylene-tetrafluoroethylene copolymer (hereinafter, also referred to as “ETFE”), perfluoro (alkyl vinyl ether) -tetrafluoroethylene copolymer (hereinafter, also referred to as “PFA”), and hexafluoropropylene. -Tetrafluoroethylene copolymer (hereinafter, also referred to as "FEP"), chlorotrifluoroethylene polymer (hereinafter, also referred to as "PCTFE"), vinyl fluoropolymer (hereinafter, also referred to as "PVDF"). , Vinylidene fluoride polymer (hereinafter, also referred to as "PVF"), vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-propylene copolymer. Examples thereof include a combination, a tetrafluoroethylene-vinylidene fluoride-propylene copolymer, an ethylene-chlorotrifluoroethylene copolymer and a propylene-chlorotrifluoroethylene copolymer. Each of these fluororesins may further have other units.

Examples of the polyester resin include polyethylene terephthalate resin, polybutylene terephthalate resin, and polylactic acid resin.
Examples of the polyolefin resin include polyethylene, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polypropylene, ethylene-propylene copolymer and the like. Each of these polyolefin resins may further have other units.

As the thermoplastic resin, a crystalline resin is preferable because it is excellent in scratch resistance, chemical resistance and the like, and high strength can be easily obtained by stretching or the like. That is, it is preferable that the thermoplastic resin film is a crystalline resin film.
Among the crystalline resins, fluororesins are preferable because they are excellent in weather resistance and chemical resistance. That is, it is preferable that the thermoplastic resin film is a fluororesin film.
Among the fluororesins, at least one selected from the group consisting of ETFE, PFA, FEP, PCTFE, PVDF and PVF is preferable in terms of excellent weather resistance, specific gravity and price, and from the group consisting of ETFE, PFA and FEP. At least one selected is more preferred, and ETFE is particularly preferred.

The thermoplastic resin film may further contain components other than the thermoplastic resin, if necessary. Examples of other components include flame retardants, ultraviolet light absorbers, ultraviolet blocking agents, fillers, pigments and the like.

The Rz on the surface of the thermoplastic resin film is typically 5 μm or less, but this is not the case when embossing or the like is performed.
The thickness of the thermoplastic resin film is typically 10 to 1,000 μm.
The width of the thermoplastic resin film is typically 0.5 to 3 m.

The root mean square height of the surface waviness measured at a position 50 mm outward from the outer edge in the width direction of the joint portion of the joined body of the present invention that joins adjacent raw fabrics (hereinafter, "root mean square height"). (50 mm from the outer edge) ”is 0.5 mm or less, preferably 0.45 mm or less, and particularly preferably 0.40 mm or less. When the root mean square height (50 mm from the outer edge) is not more than the above upper limit value, the scratch resistance of the joint is excellent. The smaller the root mean square height (50 mm from the outer edge), the more preferable, and 0 mm may be used.
The "root mean square height of the surface swell shape" is an index indicating the size of wrinkles, and is measured by the following measuring method.
When the raw fabrics are welded to each other by heating and pressing the welding target region, if the heat is applied to a region other than the welding target region of the raw fabrics, the root mean square height (50 mm from the outer edge) becomes large. The root mean square height (50 mm from the outer edge) is set to 0 by setting the temperature measured by the thermocouple placed on the surface of the original fabric at a position 50 mm outward from the outer edge in the width direction of the welding target region to 40 ° C or less. It can be 1.5 mm or less.

(Measuring method of root mean square height)
Horizontally, from a line laser installed at a position 80 mm directly above a joint having a width of 250 mm and a length of 700 mm in which both ends in the flow direction are stretched with a tension of 73.7 g, in the width direction of the joint of the joint. A laser beam having a wavelength of 635 nm is irradiated at a position 50 mm outward from the outer edge with a length of 150 mm along the flow direction. The portion of the bonded body irradiated with the laser beam is used as the irradiation portion. It is projected onto the irradiation area by an area camera (resolution 0.08 mm, shutter speed 10 ms, F value F16, focal length 55 mm) installed at a position 250 mm outside the irradiation area and 25 mm above the height direction. The image is taken horizontally in the width direction of the joint with the irradiation part as the focus position. The swell of the captured image is geometrically transformed to obtain the surface swell shape. In the geometric transformation, the pixel coordinates are multiplied by 0.08 (resolution) and converted to the mm coordinates. Calculate the standard deviation of the obtained surface swell shape in the height direction, and use that value as the root mean square height.

A method of calculating the standard deviation in the height direction will be described in more detail with reference to FIG. FIG. 3 is a diagram schematically showing the surface waviness shape obtained by geometrically transforming the pixel coordinates of the captured image.
The average value of the height data X _i (integer of i = 1 to n) of n mm coordinates obtained by geometrically transforming the n pixel coordinates is defined as the average height X _ave, and the standard in the height direction is calculated by the following equation 1. Calculate the deviation. n is the number of pixels, and n = 710.

The root mean square height of the surface waviness measured at a position 1 mm outward from the outer edge of the joint in the width direction of the joint of the present invention (hereinafter, also referred to as "root mean square height (1 mm from the outer edge)"). ) Is preferably 0.5 mm or less, and particularly preferably 0.45 mm or less. When the root mean square height (1 mm from the outer edge) is not more than the upper limit value, the scratch resistance of the joint is more excellent. The smaller the root mean square height (1 mm from the outer edge) is, the more preferable, and 0 mm may be used.
When the raw fabrics are welded to each other by heating and pressing the welding target region, if the heat is applied to a region other than the welding target region of the raw fabric, the root mean square height (1 mm from the outer edge) tends to increase. .. The root mean square height (1 mm from the outer edge) is set to 0 by setting the temperature measured by the thermocouple placed on the surface of the original fabric at a position 50 mm outward from the outer edge in the width direction of the welding target region to 40 ° C or less. It can be 1.5 mm or less.

The root mean square height of the surface waviness measured at a position 50 mm outward from the center of the width direction of the joint of the joint of the present invention (hereinafter, also referred to as "root mean square height (50 mm from the center)"). ) Is preferably 0.5 mm or less. When the root mean square height (50 mm from the center) is not more than the upper limit value, the scratch resistance of the joint is more excellent. The smaller the root mean square height (50 mm from the center), the more preferable, and 0 mm may be used.
When the raw fabrics are welded to each other by heating and pressing the welding target region, if the heat is applied to a region other than the welding target region of the raw fabrics, the root mean square height (50 mm from the center) becomes large. Further, the wider the joint portion, the larger the root mean square height (50 mm from the center) tends to be. The root mean square root is obtained by setting the temperature measured by the thermocouple placed on the surface of the original fabric at a position 50 mm outward from the outer edge in the width direction of the welding target region to 40 ° C or lower and the width of the joint to 8 mm or lower. The height (50 mm from the center) can be 0.5 mm or less.

The tensile breaking strength of the bonded body is preferably 25 MPa or more, more preferably 35 MPa or more, and particularly preferably 45 MPa or more. When the tensile breaking strength is at least the above lower limit value, it can be used in applications where the strength of the bonded body is required, for example, for membrane structures.
The upper limit of the tensile breaking strength of the bonded body is not particularly limited, and is, for example, 60 MPa.

The bonded body of the present invention can be produced by the method for producing a bonded body of the present invention described later.
In the manufacturing method, the width of the joint can be adjusted by the overlapping width of the two raw fabrics and the width of the target region to be heated and pressed. The larger the overlap width, the wider the width of the joint. Usually, the overlapping width is narrower than the width of the target area, and the maximum width of the target area roughly matches the width of the joint. When obtaining a bonded body having a joint portion width of 1 to 8 mm, the overlapping width is preferably 0 to 5 mm, particularly preferably more than 0 mm and 5 mm or less.
However, the method for producing the bonded body of the present invention is not limited to this.

The joint body of the present invention has excellent scratch resistance because the root mean square height of the surface waviness at a position 50 mm outward from the outer edge in the width direction of the joint portion is 0.5 mm or less.
According to the study by the present inventors, the larger the wrinkles in the vicinity of the joint, the greater the variation in the crystallinity of the raw fabric in the vicinity of the joint. The portion having a low degree of crystallinity is easily scratched, and the presence of such a portion reduces the scratch resistance of the bonded body. Further, since the wrinkles are large, the joints are easily rubbed with other members, so that the scratch resistance of the joint is lowered.
In the bonded body of the present invention, since the root mean square height of the surface waviness shape at the above position is 0.5 mm or less, the variation in crystallinity in the vicinity of the joint portion is small and scratches are likely to occur. There are few parts. In addition, since the swell is small, it does not easily rub against other members. Therefore, it is considered to be excellent in scratch resistance.

[Manufacturing method of bonded body]
In the method for manufacturing a bonded body of the present invention, a pair of endless strips are rotated so that opposing portions travel forward, and two raw fabrics made of a thermoplastic resin film are formed into the width of each raw fabric. In a state where the ends in the directions are overlapped or abutted against each other and brought into contact with each other, the pair of endless strips are sandwiched between the outer peripheral surfaces of the opposing portions, and the two original fabrics come into contact with each other. The step of welding the two raw fabrics by heating and pressing the welding target area including the portion to be welded from both sides is performed at least once.
Hereinafter, a case where the welding device 100 illustrated in FIG. 4 is used will be described as an example of the method for producing the bonded body of the present invention.

(Welding device)
FIG. 4 is a schematic configuration diagram of the welding device 100. FIG. 5 is a partial cross-sectional view showing a part of the IV-IV cross section in FIG.
As shown in FIGS. 4 to 5, the welding device 100 includes a pair of endless strips 10A and 10B and a pair of welding portions 20A and 20B.

The endless band-shaped body is a member in which the band-shaped body is made into an annular shape by joining the ends in the length direction to each other.
The pair of endless strips 10A and 10B are arranged one above the other. Further, the endless strip-shaped bodies 10A and 10B are each rotatably supported in the first direction (direction of arrow X in FIG. 4) by a plurality of support rolls 11.
When the pair of endless strips 10A and 10B are rotated in the first direction, the pair of endless strips 10A and 10B face each other, that is, the portion of the endless strip 10A facing the endless strip 10B and the endless. The portions of the strip 10B facing the endless strip 10A are arranged so as to travel in the forward direction. The forward travel is to travel from the upstream side to the downstream side of the MD. By traveling in the forward direction in this way, two traveling paths of the original fabric 3 are formed between the outer peripheral surfaces 10a and 10b of the opposite portions of the pair of endless strips 10A and 10B. The traveling path is such that the two original fabrics 3 are traveled in a state where the ends in the width direction of each are overlapped or abutted against each other and brought into contact with each other. FIG. 5 shows an example in which the widthwise ends of the two original fabrics 3 are overlapped with each other and brought into contact with each other.

The welded portion 20A is arranged at a position facing the traveling path inside the endless strip-shaped body 10A. The welded portion 20A includes two heating units 21A and 23A (heating mechanism), two cooling units 31A and 33A (first cooling mechanism) arranged in the vicinity of the heating units 21A and 23A, and heating units 21A and 23A. A pressing roll 25A arranged on the downstream side of the pressing roll 25A and a cooling unit 27A (second cooling mechanism) arranged on the downstream side of the pressing roll 25A are provided. Of the two heating units 21A and 23A, the heating unit 23A is arranged on the downstream side of the heating unit 21A.

The welded portion 20B is arranged at a position facing the traveling path inside the endless strip-shaped body 10B. The welded portion 20B includes two heating units 21B and 23B (heating mechanism), two cooling units 31B and 33B (first cooling mechanism) arranged in the vicinity of the heating units 21B and 23B, and heating units 21B and 23B. A pressing roll 25B arranged on the downstream side of the pressing roll 25B and a cooling unit 27B (second cooling mechanism) arranged on the downstream side of the pressing roll 25B are provided. Of the two heating units 21B and 23B, the heating unit 23B is arranged on the downstream side of the heating unit 21B.

Of the two heating units of the welded portions 20A and 20B, the heating unit 21A and the heating unit 21B on the upstream side are arranged at positions facing each other with the traveling path in between. Similarly, the heating unit 23A and the heating unit 23B on the downstream side are also arranged at positions facing each other with the traveling path in between. That is, two pairs of heating units 21A, 21B and 23A, 23B are provided in the middle of the traveling path on which the two raw fabrics travel, and the welding target area of the two raw fabrics traveling on the traveling route is divided into two stages from both sides. Can be heated.
The four cooling units 31A, 31B, 33A, and 33B are attached to the four heating units 21A, 21B, 23A, and 23B, respectively, and from each heating unit, other than the welding target area of the two raw fabrics 3 traveling on the traveling path. Heat transfer to the region can be suppressed.
The pressing roll 25A and the pressing roll 25B are arranged at positions facing each other via the traveling path, and can press the welding target regions of the two raw fabrics 3 heated on the upstream side traveling on the traveling path from both sides. The widths of the pressing rolls 25A and 25B are the same as or less than the widths of the endless strips 10A and 10B.
The cooling unit 27A and the cooling unit 27B are arranged at positions facing each other via the traveling path, and cool the welding target regions of the two raw fabrics heated and pressed on the upstream side traveling on the traveling path from both sides. Can be solidified. The cooling units 27A and 27B are, for example, water cooling plate type cooling units.

<Endless band>
FIG. 6 shows an example of an endless band-shaped body that can be used as the endless band-shaped bodies 10A and 10B.
The endless band-shaped body 10 shown in FIG. 6 includes an endless band-shaped woven fabric layer 13 and a polytetrafluoroethylene (hereinafter, also referred to as “PTFE”) layer 15 laminated on the outer peripheral surface of the woven fabric layer 13. .. The PTFE layer 15 has a multilayer structure in which the PTFE coat layer 17 and the PTFE film layer 19 are laminated in this order from the woven fabric layer 13 side. The Rz of the outer peripheral surface 10c of the endless strip 10, that is, the outer peripheral surface of the PTFE layer 15 is preferably 15 μm or less, more preferably 5 μm or less, further preferably 1 μm or less, and particularly preferably 0.7 μm or less.
The surface of the woven fabric layer 13 is uneven due to the fibers. Since the PTFE layer 15 is provided on the woven fabric layer 13, the outer peripheral surface 10c of the endless strip-shaped body 10, that is, the surface in contact with the original fabric 3 is flattened, and Rz is equal to or less than the upper limit value.
The width of the endless strip 10 is, for example, 1 to 10 cm.

When the Rz of the outer peripheral surface 10c of the endless band-shaped body 10, that is, the Rz of the outer peripheral surfaces 10a and 10b of the endless band-shaped bodies 10A and 10B is not more than the upper limit value, the welding strength of the two raw fabrics 3 is excellent. For example, even if the width of the area to be welded, that is, the width of the raw fabric welded portion (joint portion) where the raw fabrics are welded to each other is 1 to 8 mm, the tensile breaking strength of the raw fabric welded portion is 50, which is the tensile breaking strength of the original fabric 3. Can be over%. The smaller the maximum height roughness Rz of the outer peripheral surfaces 10a and 10b is, the more preferable, and 0 μm may be used.
Generally, when welding is performed with a wide welding width, the resin melted in the welding process adheres to the outer peripheral surfaces 10a and 10b of the endless strips 10A and 10B, and the welding strength is rather weakened by the influence of the adhesive force. Therefore, it can be said that it is preferable to increase Rz.
However, in the present invention, when the width of the raw fabric welded portion is 1 to 8 mm, the molten resin is relatively difficult to adhere to the outer peripheral surfaces 10a and 10b, and the adhesive force is also small. The adhesion can be suppressed by a cooling unit or the like. It is considered that by reducing Rz, the overlapping portion of the original fabric is effectively extended, which leads to an increase in crystallinity.

Examples of the fibers constituting the woven fabric layer 13 include glass fibers, aramid fibers, carbon fibers and the like. Any one of these fibers may be used alone or two or more thereof may be used in combination. Among the above, glass fiber is preferable because it has excellent heat resistance and is inexpensive.
Examples of the type of weaving of the woven fabric layer 13 include plain weave, twill weave, satin weave and the like.
The thickness of the woven fabric layer 13 is, for example, 10 to 100 μm.
The Rz on the surface of the woven fabric layer 13 is usually more than 15 μm and less than 100 μm.

The mass per unit area of the PTFE coat layer 17 (the amount of PTFE applied) is, for example, 50 to 150 g / m ² .
The thickness of the PTFE film layer 19 is preferably 10 to 200 μm, particularly preferably 50 to 150 μm. When the thickness of the PTFE film layer 19 is equal to or greater than the lower limit, the unevenness on the surface of the woven fabric layer 13 is less likely to be reflected on the outer peripheral surface of the PTFE film layer 19, and the Rz of the outer peripheral surface 10c of the endless strip 10 is the upper limit. It tends to be as follows. As a result, the Rz on the surface of the raw fabric welded portion becomes equal to or less than the upper limit value, and the scratch resistance and tensile breaking strength of the raw fabric welded portion are excellent. When the thickness of the PTFE film layer 19 is not more than the upper limit value, the handleability is excellent.

As a method for producing the endless band-shaped body 10, for example, a PTFE dispersion liquid containing PTFE and a dispersion medium is applied to the outer peripheral surface of the endless band-shaped woven fabric (woven fabric layer 13) and dried to form a PTFE coat layer 17. , A method of laminating a PTFE film on the PTFE coat layer 17 can be mentioned.
The endless strip-shaped woven fabric is obtained by joining one end and the other end of the strip-shaped woven fabric in the length direction to form an annular shape. The woven fabrics can be joined by a conventional method. An existing endless band-shaped woven fabric may be used.
Examples of the method for applying the PTFE dispersion liquid include a method of applying the PTFE dispersion liquid by die coating, dip coating, spray coating or the like. A commercially available product may be used as the PTFE dispersion. The drying method is, for example, heating above the boiling point of the dispersion medium.
The Rz on the surface of the PTFE film is preferably 15 μm or less, and a more preferable range is as described above. The preferred thickness of the PTFE film is similar to the preferred thickness of the PTFE film layer 19.
Examples of the method for laminating the PTFE film include thermal laminating and laminating using an adhesive layer.
The PTFE coat layer 17 may be formed before the strip-shaped woven fabric is made into an endless strip.

The endless band-shaped body used in the present invention is not limited to the endless band-shaped body 10.
For example, the PTFE layer 15 may consist of only the PTFE film layer 19 or only the PTFE coat layer 17.
The PTFE coat layer 17 may be provided on both sides of the woven fabric layer 13. The PTFE film layer 19 may be provided on both sides of the woven fabric layer 13.

In a single application of the PTFE dispersion, a part of the PTFE is usually impregnated into the woven fabric, and the surface of the PTFE coat layer 17 is uneven. By repeating the application of the PTFE dispersion liquid, it is possible to set Rz to the above upper limit value or less only with the PTFE coat layer 17, but the process is complicated and costly. Therefore, the method of laminating the PTFE film is convenient and preferable.
The PTFE film may be directly laminated on the outer peripheral surface of the woven fabric layer 13 without forming the PTFE coat layer 17.
The endless band-shaped woven fabric layer 13 may be used as it is as the endless band-shaped body.

<Heating unit>
The heating unit 21A is a hot plate type heating unit (hot plate type heating mechanism), and includes a hot plate 29 and a heater (not shown) for heating the hot plate 29.
The hot plate 29 has a flat plate-shaped base portion 29a and a convex portion 29b protruding from the base portion 29a toward the endless band-shaped body 10A, and has a T-shaped TD cross section.
The convex portion 29b has a front end surface 29c and a first side surface 29d and a second side surface 29e extending from both ends of the TD of the tip surface 29c in the direction of the base portion 29a. The hot plate 29 is arranged with the tip surface 29c facing the traveling path side. The tip surface 29c is in contact with the inner peripheral surface of the endless band 10A, and when the hot plate 29 is heated to an arbitrary temperature by the heater, the portion in contact with the tip surface 29c of the endless band 10A is heated and the heat thereof is generated. Heats the welding target region of the original fabric 3 traveling on the traveling path.
Width of the end surface 29c is the same as the width W ₁ of the two raw 3 of the welding target area. The width W ₁ of the region to be welded is typically wider than the overlapping width W _{2 of the two} original fabrics 3. Therefore, the width of the tip surface 29c in TD is also typically wider than the overlapping width W _{2 of the two} original fabrics 3.

The other heating units 21B, 23A, and 23B are also hot plate type heating units, and each has the same configuration as the heating unit 21A.

The width of the tip surface 29c of the heating units 21A and 21B on the upstream side and the width of the tip surface 29c of the heating units 23A and 23B on the downstream side may be the same or different. For example, the width of the tip surface 29c of the heating units 21A and 21B may be narrower than the width of the tip surface 29c of the heating units 23A and 23B.
The widest of the width of the tip surface 29c of the heating units 21A and 21B and the width of the tip surface 29c of the heating units 23A and 23B is the width of the raw fabric welded portion of the obtained bonded body.

<Cooling unit>
As shown in FIG. 5, the cooling unit 31A is a water cooling plate type cooling unit (water cooling mechanism) including a pair of water cooling plates 35 and 37 arranged on both sides of the TD of the heating unit 21A.
On the other hand, the water cooling plate 35 has an L-shaped TD cross section, and is arranged on the first side surface 29d side (left side in FIG. 5) of the convex portion 29b of the hot plate 29 at a distance from the hot plate 29. .. The water cooling plate 35 covers the surface and side surface of the base 29a on the endless band 10A side, the surface on the first side surface 29d side, and the first side surface 29d.
The other water-cooled plate 37 has a TD cross section L-shaped symmetrical with that of the water-cooled plate 35, and is located on the second side surface 29e side (right side in FIG. 5) of the convex portion 29b of the hot plate 29 and between the hot plate 29. Arranged at intervals. The water-cooled plate 37 covers the surface and side surface of the base 29a on the endless strip 10A side, the surface on the second side surface 29e side, and the second side surface 29e.
Examples of the water cooling plates 35 and 37 include those using a chiller.

In the cooling unit 31A, the water cooling plates 35 and 37 cool the atmosphere between the hot plate 29 and the endless strip 10A, so that the heat radiated from the surface other than the tip surface 29c of the hot plate 29 is released. It can be prevented from propagating to a region other than the welding target region of the raw fabric 3 and raising the temperature of the raw fabric 3.
Further, the water cooling plates 35 and 37 are arranged so that the tip of the convex portion 29b of the hot plate 29 protrudes toward the endless strip 10A side from the surfaces 35a and 37a on the endless strip 10A side of the water cooling plates 35 and 37. Will be done. That is, when the tip surface 29c of the convex portion 29b comes into contact with the endless strip 10A, the water cooling plates 35 and 37 do not come into contact with the endless strip 10A. As a result, wear of the endless strip 10A due to contact of the water cooling plates 35 and 37 with the rotating endless strip 10A can be suppressed.

The distance between the first side surface 29d of the hot plate 29 and the water cooling plates 35 and 37 is preferably 0.1 to 10 mm, particularly preferably 0.5 to 5 mm. When this interval is within the above range, the effect of suppressing heat transfer to a region other than the welding target region is more excellent.

The difference between the surfaces 35a and 37a on the endless strip 10A side of the water cooling plates 35 and 37 and the tip surface 29c of the convex portion 29b is preferably 0.1 to 10 mm, particularly preferably 0.5 to 5 mm. When this difference is not more than the upper limit value, the effect of suppressing heat propagation to a region other than the welding target region is more excellent, and when it is more than the lower limit value, physical contact with the endless band is avoided. , The wear of the endless band is suppressed and the durability is excellent.

The other cooling units 31B, 33A, and 33B have the same configuration as the cooling unit 31A, respectively.

(Manufacturing of joints)
In the method for manufacturing a bonded body using the welding device 100, the pair of endless strip-shaped bodies 10A and 10B are rotated so that the opposing portions travel forward. A pair of endless strips 10A and 10B face each other in a state where two raw fabrics 3 made of a thermoplastic resin film are brought into contact with each other by overlapping or abutting the ends of the original fabrics 3 in the width direction. A pair of heating units arranged above and below the traveling path in a welding target region including a portion where the two raw fabrics 3 are in contact with each other while traveling on a traveling path formed between the outer peripheral surfaces 10a and 10b of the portion. 21A and 21B are heated from both sides via the endless strips 10A and 10B to be fused (first heating step).
Next, the welding target region is heated from both sides by a pair of heating units 23A and 23B arranged above and below the traveling path via the endless band-shaped bodies 10A and 10B to be fused (second heating step).
Next, the welding target region is pressed from both sides by pressing rolls 25A and 25B arranged above and below the traveling path, and crimped (pressing step).
Next, the welding target region is cooled from both sides by cooling units 27A and 27B arranged above and below the traveling path and solidified (solidification step).
In the first heating step, the cooling units 31A and 31B transfer heat from the heating units 21A and 21B to a region other than the welding target region (hereinafter, also referred to as “other region”) of the two raw fabrics 3. It is suppressed, and the temperature measured by the thermocouple arranged on the surface of the original fabric 3 at a position 50 mm outward from the outer edge in the width direction of the welding target region is set to 40 ° C. or less.
In the second heating step, the cooling units 33A and 33B suppress the heat propagation of the two raw fabrics 3 from the heating units 23A and 23B to the other region, and from the outer edge in the width direction of the welding target region to the outside. The temperature measured by the thermocouple placed on the surface of the original fabric 3 at the position of 50 mm is set to 40 ° C. or lower.
As a result, a joined body in which two raw fabrics 3 are joined is continuously manufactured.

If necessary, the obtained bonded body is used in place of either one or both of the two raw fabrics 3, and each of the above steps is repeated. As a result, a bonded body in which three or more original fabrics 3 are bonded can be obtained.
The obtained bonded body may be subjected to a treatment such as a corona treatment or a drip treatment, if necessary.

The region to be welded after solidification is also referred to as a raw fabric welded portion. The raw fabric welded portion may be a joint portion. When running two raw fabrics with their widthwise ends overlapped with each other, at least a part of the raw fabric welded portion has a thickness of 101% or more of the thickness of the original fabric, that is, a joint. .. When two raw fabrics are run with their widthwise ends abutting against each other, the thickness of the raw fabric welded portion is less than 100% of the thickness of the original fabric.

The rotation speed of the endless strips 10A and 10B, that is, the transport speed of the two raw fabrics 3, is, for example, 0.5 to 10 m / min, preferably 1.0 to 9.0 m / min, and more preferably. Is 2.0 to 8.0 m / min. Within the above range, the tensile breaking strength of the raw fabric welded portion tends to be excellent.
The overlapping width of the two raw fabrics is preferably 0 to 40 mm, more preferably 0 to 8 mm, further preferably more than 0 mm and 8 mm or less, particularly preferably 1 to 7 mm, and most preferably 1 to 3 mm.
Here, the overlapping width of 0 mm means that the two original fabrics are run in a state where the ends in the width direction are butted against each other. When the overlapping width is more than 0 mm, it means that the two original fabrics are run in a state where the ends in the width direction are overlapped with each other.
When the overlapping width is not more than the upper limit value, the width of the raw fabric welded portion (joint portion) is narrow, so that the amount of dimensional change of the raw fabric welded portion is relatively small, and wrinkles are less likely to occur in the subsequent process. In particular, if it is 8 mm or less, even if the raw fabric welded portion is scratched during transportation or fixing to the frame, the number of scratches on the raw fabric welded portion is relatively small because the width of the raw fabric welded portion is narrow. The scratches are inconspicuous. Therefore, the appearance of the bonded body is unlikely to deteriorate, and the yield is also unlikely to decrease. When the overlapping width is 1 mm or more, the tensile breaking strength of the joint is excellent.

The heating temperatures in the first heating step and the second heating step are preferably (T-20) ° C. or higher and (T + 20) ° C. or lower, respectively, when the melting point (° C.) of the thermoplastic resin constituting the raw fabric is T. , (T-10) ° C. or higher and (T + 10) ° C. or lower are more preferable, and (T-5) ° C. or higher and (T + 5) ° C. or lower are particularly preferable.
The pressure at the time of pressing in the first heating step and the second heating step is not particularly limited and may be, for example, 0.1 to 0.5 MPa.
The heating temperature and pressure in each heating step may be the same or different.

In the first heating step and the second heating step, the temperature measured by the thermocouple arranged on the surface of the raw fabric 3 at a position 50 mm outward from the outer edge in the width direction of the welding target region of the two raw fabrics 3 is , 40 ° C. or lower, preferably 35 ° C. or lower, and particularly preferably 30 ° C. or lower. When the temperature is not more than the upper limit value, the tensile breaking strength of the raw fabric welded portion can be 50% or more of the tensile breaking strength of the raw fabric even if the overlapping width of the two raw fabrics 3 is narrow. The lower limit of the temperature is not particularly limited, and is, for example, 10 ° C.

The pressure at the time of pressing in the pressing step is preferably 0.1 to 5 MPa, particularly preferably 0.5 to 2.5 MPa.
The temperature at the time of pressing in the pressing step, that is, the surface temperature of the pressing rolls 25A and 25B is not particularly limited, and is, for example, 25 ° C.
In the cooling in the solidification step, the temperature measured by the thermocouple arranged on the surface of the original fabric 3 at a position 50 mm outward from the outer edge in the width direction of the welding target region after cooling is 10 to 40 ° C. It is preferably carried out at 15 to 35 ° C., more preferably 20 to 30 ° C., and particularly preferably 20 to 30 ° C.

In the manufacturing method of the present invention, when heating is performed by the heating units 21A, 21B, 23A, 23B, the raw fabric 3 is located 50 mm outward from the outer edge in the width direction of the welding target region of the two raw fabrics 3. Since the ambient temperature in the vicinity measured by the thermocouple arranged on the surface of the above upper limit is set to be equal to or lower than the upper limit, the occurrence of wrinkles can be suppressed.
The outer peripheral surfaces of the endless strips 10A and 10B are pressed against the surface of the heated welding target region.
In the conventional technique, when heat propagates to a region other than the welding target region (other region), orientation relaxation due to heat shrinkage occurs in the other region, especially in a portion close to the welding target region to be heated, and sink marks and swells associated therewith occur. It becomes wrinkled. Specifically, in a part of another region, the temperature rises due to the propagated heat, exceeds the glass transition temperature (Tg) of the thermoplastic resin, that portion becomes an amorphous region, the molecular chain moves, and then recrystallization occurs. As a result, it is considered that the crystal region partially grew and the crystallinity varied, resulting in wrinkles.
In the manufacturing method, the temperature measured by the thermocouple arranged on the surface of the original fabric 3 at a position 50 mm outward from the outer edge in the width direction of the target region is set to be equal to or lower than the upper limit value, so that the two sheets are formed. The heat propagation of the original fabric 3 to other regions is sufficiently suppressed, and the relaxation of orientation in other regions is suppressed. Therefore, a joint with less wrinkles can be obtained. In addition, variations in crystallinity in the vicinity of the joint can be suppressed.

When the target region is at a high temperature due to heating, the original fabric 3 is likely to adhere to the outer peripheral surfaces of the endless strips 10A and 10B. When this adhesive force is high, a part of the original fabric 3 adheres to the endless strips 10A and 10B, so that a part of the original fabric 3 is missing and unevenness is generated, or a part of the joint portion is peeled off. It causes. In addition, the original fabric 3 is locally pulled and easily distorted, which causes wrinkles.
In the manufacturing method, when the welding target region is narrowed, for example, 8 mm or less, the adhesive force generated between the outer peripheral surfaces of the endless strips 10A and 10B and the original fabric 3 can be suppressed to a low level. Further, even if the temperature of the heated target region is rapidly lowered, the raw fabric 3 is less likely to adhere to the endless strips 10A and 10B. By suppressing the adhesion between the outer peripheral surfaces of the endless strips 10A and 10B and the original fabric 3, wrinkles are less likely to occur.

(Other embodiments)
The method for producing a bonded body of the present invention is not limited to the method using the welding device 100 of the illustrated example.
For example, an example of using a water cooling plate type cooling mechanism (cooling units 31A, 31B, 33A, 33B) as the first cooling mechanism for suppressing heat transfer from the heating mechanism has been shown, but other water cooling mechanisms may also be used. Often, an air cooling mechanism may be used. For example, in the case of an air cooling mechanism, heat propagation to other regions can be suppressed by sending an air flow of an arbitrary temperature to the atmosphere between the heating units 21A, 21B, 23A, 23B and the endless strips 10A, 10B.
An example is shown in which the welding portions 20A and 20B each have two heating mechanisms (heating units 21A and 21B, heating units 23A and 23B) and the welding target region is heated in two stages, but each of the welding portions 20A and 20B has. The heating mechanism may be one or three or more, and the welding target region may be heated in one step or three steps or more.

Hereinafter, the present invention will be described in detail with reference to examples. However, the present invention is not limited to the following description. “%” Indicates “mass%” unless otherwise specified.
Example 1 is an example, and Examples 2 to 5 are comparative examples.
The evaluation methods and materials used in each example are shown below.

[Maximum Height Roughness Rz and Arithmetic Mean Roughness Ra]
ISO4287: 1997, Amd. Based on 1: 2009 (JIS B0601: 2001), Rz and the arithmetic mean roughness Ra were measured with the reference length rl (cutoff value λc) for the roughness curve set to 0.8 mm.

[Square mean square root height of surface swell shape]
A 250 mm wide joint was horizontally stretched with a length of 700 mm by applying a tension of 73.7 g to both ends of the MD. From a line laser installed 80 mm directly above the stretched joint, a laser with a length of 150 mm along the MD and a wavelength of 635 nm, 50 mm outward from the outer edge of the joint in the width direction of the joint. Irradiated with light. An area camera (resolution 0.08 mm, shutter speed 10 ms, F value F16) installed at a position 250 mm outward in the width direction and 25 mm upward in the height direction from the irradiation part (the part of the junction irradiated with the laser beam). , The focal length is 55 mm), and the image projected on the irradiation portion was photographed horizontally in the width direction of the joint portion with the irradiation portion as the focus position. The swell of the photographed image was geometrically transformed to obtain a surface swell shape. In the geometric transformation, the coordinates of 710 pixels were each multiplied by 0.08 (resolution) and converted into mm coordinates. The average value of the height data X _i (integer of i = 1 to 710) of these mm coordinates is defined as the average height X _ave , the standard deviation (mm) in the height direction is calculated by the above equation 1, and the value is used as the value. The root mean square height was used.
The root mean square height was obtained in the same manner as described above for the position 1 mm outward from the outer edge of the joint portion in the width direction and the position 50 mm outward from the center in the width direction of the joint portion.
When welding itself was impossible, it was described as "x".

〔material〕
The following items were prepared as the original fabric.
ETFE film: An ETFE film having a thickness of 100 μm (melting point: about 270 ° C.).

The following items were prepared as endless strips.
Endless band shape 1: Endless band shape having the structure shown in FIG. 6 (woven fabric layer: glass fiber woven fabric, plain weave. Thickness of PTFE film layer: 100 μm, Rz of outer peripheral surface: 0.63 μm, arithmetic average coarseness of outer peripheral surface Ra: 0.1 μm).

[Example 1]
A bonded body was manufactured by the following procedure using the welding device 100 having the configuration shown in FIGS. 4 to 5. As the endless band-shaped bodies 10A and 10B, the endless band-shaped body 1 was used. The width of the tip surfaces of the first-stage heating units 21A and 21B was 3 mm, and the width of the tip surfaces of the second-stage heating units 23A and 23B was 5 mm.
As shown in FIG. 7, the ends of the two ETFE films (width 250 mm) are overlapped with each other with an overlapping width of 1 mm, and the outer peripheral surfaces 10a of the opposing portions of the pair of endless strips 10A and 10B that rotate. The traveling path formed between 10b was traveled. The first-stage heating units 21A and 21B and the second-stage heating units 23A and 23B sequentially heat from both sides, press the pressing rolls 25A and 25B from both sides, and cool the cooling units 27A and 27B from both sides. And obtained a joint. During heating in the heating units 21A, 21B, 23A, 23B, the cooling units 31A, 31B, 33A, 33B suppressed heat transfer from each heating unit to other regions of the two raw fabrics.
The rotation speed of the endless strips 10A and 10B, that is, the transport speed of the original fabric was set to 2 m / min, 5 m / min, or 8 m / min. The heating conditions in the heating units 21A and 21B were a heating temperature of 270 ° C., 275 ° C. or 280 ° C., and a pressure of 0 MPa. The heating conditions in the heating units 23A and 23B were the same as those in the heating units 21A and 21B except that the pressure was 0.1 MPa. The pressing conditions on the pressing rolls 25A and 25B were a temperature of 25 ° C. and a pressure of 2.5 MPa. For cooling in the cooling units 27A and 27B, the surface temperature of the target area was set to 30 ° C. The cooling in the cooling units 31A, 31B, 33A, 33B is performed by thermoelectrics arranged on the surface of the original fabric 3 at a position 50 mm outward from the outer edge in the width direction of the target region during heating in the first heating step and the second heating step. The temperature measured in pairs was set to the temperature shown in Table 1. As the thermocouple, a data logger GL220 manufactured by GLARHTEC was used. The width of the joint portion of the obtained joint body was 3.9 mm, and the thickness of the joint portion was 120 μm (120% of the original fabric).

[Example 2]
In the welding device 100, the cooling units 31A, 31B, 33A, 33B were removed, and the heat transfer from each heating unit to the other region of the two raw films was not suppressed, and the first stage heating units 21A, 21B The width of the tip surface (width of the area to be heated for the first time) was set to 25 mm, and the width of the tip surface (width of the area to be heated for the second time) of the second stage heating units 23A and 23B was set to 30 mm, and two sheets. As shown in FIG. 8, the ends of the ETFE film (width 250 mm) are overlapped with an overlapping width of 20 mm, and the ETFE film having a width of 30 mm is overlapped on the overlapping portion so as to straddle the overlapping portion. A joint was produced in the same manner as in Example 1 except that The width of the joint portion of the obtained joint body was 28.6 mm, and the thickness of the joint portion was 280 μm (280% of the original fabric thickness).

[Example 3]
The width of the tip surfaces of the first-stage heating units 21A and 21B (width of the region to be heated for the first time) is 10 mm, and the width of the tip surfaces of the second-stage heating units 23A and 23B (width of the region to be heated for the second time). ) Was set to 20 mm, and as shown in FIG. 9, a bonded body was produced in the same manner as in Example 2 except that the ETFE film having a width of 30 mm was not superposed on the overlapping portion of the two ETFE films. The width of the joint portion of the obtained joint body was 18.9 mm, and the thickness of the joint portion was 170 μm (170% of the original fabric thickness).

[Example 4]
The width of the tip surface of the first-stage heating units 21A and 21B (width of the region to be heated for the first time) and the width of the tip surface of the second-stage heating units 23A and 23B (width of the region to be heated for the second time). A bonded body was manufactured in the same manner as in Example 2 except that the respective ends were set to 30 mm and the edges of the two ETFE films were butted without overlapping as shown in FIG. The ETFE film having a width of 30 mm was arranged so that the central position in the width direction coincided with the abutting position of the two ETFE films. The width of the joint portion of the obtained joint body was 29.1 mm, and the thickness of the joint portion was 180 μm (180% of the original fabric thickness).

[Example 5]
In the welding device 100, the cooling units 31A, 31B, 33A, and 33B were removed, and the bonded body was formed in the same manner as in Example 1 except that the heat transfer from each heating unit to the other region of the two raw fabrics was not suppressed. Manufactured. The width of the joint portion of the obtained joint body was 3.9 mm, and the thickness of the joint portion was 130 μm (130% of the original fabric thickness).

The root mean square height of the surface swell shape at positions 50 mm and 1 mm outward from the outer edge of the joint portion in the width direction of the joints obtained in Examples 1 to 5 and at a position 50 mm outward from the center in the width direction of the joint portion. The results are shown in Table 1.

The joint of Example 1 has a root mean square height of 0.5 mm at both positions 50 mm and 1 mm outward from the outer edge in the width direction of the joint and 50 mm outside the center in the width direction of the joint. It was below, and there were few wrinkles.
The bonded body of Examples 2 to 5 in which the temperature measured by a thermocouple placed on the surface of the original fabric at a position 50 mm outward from the outer edge in the width direction of the target region when heating the target region was over 40 ° C. The root mean square height at a position 50 mm outward from the outer edge in the width direction of the joint exceeded 0.5 mm, and wrinkles were large.

The bonded film of the present invention can be used as a film for a film structure (for example, an outer coating film for a film structure) or an agricultural film (for example, an agricultural house coating film).
Membrane structures are structures such as roofs, outer walls, and facilities that use film. Examples of facilities include sports facilities (pools, gymnasiums, tennis courts, soccer fields, etc.), warehouses, meeting places, exhibition halls, and horticultural facilities (horticultural houses, agricultural houses, etc.).
The entire contents of the specification, claims, abstract and drawings of Japanese Patent Application No. 2017-226590 filed on November 27, 2017 are cited here as the disclosure of the specification of the present invention. It is something to incorporate.

1 assembly, 1a joints, 3 raw, 5 samples, _{W a} junction width, 10, 10A, 10B endless strip, 10a, 10b, the outer peripheral surface of 10c the endless strip, 11 the support rolls, 20A, 20B Welding part, 21A, 21B, 23A, 23B heating unit (heating mechanism), 25A, 25B pressing roll, 27A, 27B cooling unit (second cooling mechanism), 29 heating plate, 29a base, 29b convex part, 29c tip surface , 29d 1st side surface, 29e 2nd side surface, W ₁ width of welding target area, W ₂ overlapping width, 30 cooling mechanism, 31A, 31B, 33A, 33B cooling unit (first cooling mechanism), 35, 37 water cooling plate , 100 Welding device

Claims (15)

It is a bonded body in which at least two raw fabrics made of a thermoplastic resin film are bonded.
A joint body characterized in that the root mean square height of the surface waviness measured at a position 50 mm outward from the outer edge in the width direction of the joint portion between adjacent raw fabrics is 0.5 mm or less. The joint according to claim 1, wherein the root mean square height of the surface waviness measured at a position 1 mm outward from the outer edge in the width direction of the joint is 0.5 mm or less. The joint according to claim 1 or 2, wherein the width of the joint is 1 to 40 mm. The bonded body according to any one of claims 1 to 3, wherein the thermoplastic resin film is a crystalline resin film. The bonded body according to any one of claims 1 to 4, wherein the thermoplastic resin film is a fluororesin film. The fluororesin is an ethylene-tetrafluoroethylene copolymer, perfluoro (alkyl vinyl ether) -tetrafluoroethylene copolymer, hexafluoropropylene-tetrafluoroethylene copolymer, chlorotrifluoroethylene polymer, vinyl fluoride polymer. , Vinylidene fluoride copolymer, vinylidene fluoride-hexafluoropropylene copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride copolymer, tetrafluoroethylene-propylene copolymer, tetrafluoroethylene-vinylidene fluoride- The conjugate according to claim 5, which is at least one selected from the group consisting of a propylene copolymer, an ethylene-chlorotrifluoroethylene copolymer and a propylene-chlorotrifluoroethylene copolymer. The bonded body according to any one of claims 1 to 6, which is a film for a film structure. The bonded body according to any one of claims 1 to 6, which is an agricultural film. A pair of endless strips are rotated so that the opposing portions travel forward, and two raw fabrics made of a thermoplastic resin film are overlapped with each other at the widthwise end portions of the raw fabrics. In a state of being in contact with each other, the pair of endless strips are sandwiched between the outer peripheral surfaces of the opposing portions of the pair of endless strips, and the welding target region including the portion where the two raw fabrics are in contact with each other is covered from both sides. It is a method of producing a bonded body in which the two raw fabrics are welded at least once by performing the step of heating and pressing and welding the two raw fabrics at least once.
When heating the welding target region, the temperature measured by a thermocouple arranged on the surface of the raw fabric at a position 50 mm outward from the outer edge in the width direction of the welding target region is set to 40 ° C. or less. A method for manufacturing a bonded body. The manufacturing method according to claim 9, wherein the overlapping width of the two raw fabrics is 0 to 40 mm. The production method according to claim 9 or 10, wherein the thermoplastic resin film is a crystalline resin film. The production method according to any one of claims 9 to 11, wherein the thermoplastic resin film is a fluororesin film. At least a pair of hot plate type heating mechanisms are provided in the middle of the traveling path through which the two raw fabrics travel, and the welding target region is heated by the at least pair of hot plate type heating mechanisms, and the hot plate type heating mechanism is used to heat the region. The production method according to any one of claims 9 to 12, wherein the heat transfer of the two raw fabrics to a region other than the welding target region is suppressed by the first cooling mechanism. The manufacturing method according to claim 13, wherein the first cooling mechanism is a water cooling mechanism or an air cooling mechanism. It is provided with a pair of endless strips arranged so that opposing portions travel forward when rotated, and a pair of welded portions.
Two raw fabrics made of a thermoplastic resin film are brought into contact with each other by overlapping or abutting the widthwise ends of the raw fabrics between the outer peripheral surfaces of the opposite portions of the pair of endless strips. A traveling path is formed so that the traveling path is formed, and the pair of welded portions are arranged at positions inside the pair of endless strips facing the traveling path.
Each of the pair of welded portions includes at least one hot plate type heating mechanism, a first cooling mechanism arranged in the vicinity of the hot plate type heating mechanism, and a pressing roll arranged on the downstream side of the hot plate type heating mechanism. A second cooling mechanism arranged on the downstream side of the pressing roll is provided.
The first cooling mechanism is a welding device provided so as to suppress heat propagation from the hot plate type heating mechanism to a region other than the target region of the two raw fabrics.

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