JPH0423901B2 - - Google Patents

Description

[Detailed description of the invention]

"Industrial Application Field" The present invention is a composite film in which a soft vinyl chloride resin film is used as the base layer, in which a vinyl chloride resin is laminated with another resin that cannot be processed by high frequency welding. It concerns an improved method of processing. ``Conventional technology'' In recent years, farmers have been promoting the cultivation of useful plants in agricultural greenhouses (greenhouses) or tunnels in order to increase profitability.
Suppressed cultivation methods are widely used. As coating materials for agricultural greenhouses, tunnels, etc., soft vinyl chloride resin films, polyethylene films, ethylene-vinyl acetate copolymer films, polyethylene terephthalate films, etc. are used. Among these, soft vinyl chloride resin film is easier to mix with various additives than other synthetic resin films, and depending on the type of these additives, it has excellent weather resistance, anti-fog properties, heat retention, transparency, and toughness. It is most commonly used because it produces a film with excellent properties and durability. However, since the soft vinyl chloride resin film with these characteristics contains various additives such as plasticizers, antifogging agents, and stabilizers, these plasticizers and other substances may damage the film surface during use. As a result, dust particles adhere to the film surface, reducing light transmittance.
The weather resistance deteriorates, and the handleability becomes worse due to stickiness during width joint processing, stretching work, and ventilation work. As a method to solve these drawbacks, for example, to prevent dust particles from adhering to the surface of a soft vinyl chloride resin film, for example, coating the surface of the soft vinyl chloride resin film with an acrylic ester resin. A method of laminating a vinylidene fluoride resin on the surface of a soft vinyl chloride resin film via an adhesive layer has been proposed and put into practical use. On the other hand, a method has been proposed in which a polyolefin resin is laminated onto a soft vinyl chloride resin film via an adhesive layer as a method for improving handling efficiency during adhesion processing and stretching work of the soft vinyl chloride resin film. The above-mentioned soft vinyl chloride laminated film, which improves the various drawbacks of soft vinyl chloride resin films, is manufactured by calendering, inflation molding, and T-die molding, but the thickness accuracy of the film,
There are limitations in terms of the size of processing machinery, and typically the maximum width of film produced is 4.6 m. In recent years, houses have become larger, and house widths of 5.4 to 12 meters or more are now required. For this reason, when a soft vinyl chloride-based laminated film is expanded into a house or the like, a width splicing process is performed to finish it to a predetermined size. Conventionally, high-frequency welding using a high-frequency sewing machine or a high-frequency welder, ultrasonic welding, etc. have been used as width seaming methods for soft PVC resin films, but high-frequency sewing machines are mainly used from the viewpoint of processing efficiency and quality of finish. has been done. The welding process using a high-frequency sewing machine takes advantage of the large dielectric loss of a soft vinyl chloride resin film and heat-seals the film using internal heat generation of the film placed in a high-frequency electric field. However, the edge of a soft vinyl chloride resin film coated with an acrylic ester resin or a soft vinyl chloride laminated film with a vinylidene fluoride resin layered on the surface of a soft vinyl chloride resin film via an adhesive layer Even if you simply overlap the parts and try to bond them with a high-frequency sewing machine, it is difficult to raise the acrylic ester resin surface and vinylidene fluoride resin surface above the thermal melting temperature due to internal heat generation, and the acrylic ester resin surface Even if the vinylidene fluoride resin surface and the soft vinyl chloride resin surface are directly placed on top of each other, they cannot be thermally welded. In addition, a soft vinyl chloride laminated film, in which a polyolefin layer is laminated on a soft vinyl chloride resin film via an adhesive layer, has a weak interlayer adhesive strength between the polyolefin layer and the soft vinyl chloride laminated film layer, so it is possible to directly stack the polyolefin layer and heat it. Even if it is welded, it is not practical. For this reason, the width splicing method for soft vinyl chloride laminated films involves butting the ends of the vinyl chloride surfaces of the soft vinyl chloride laminated films together, and welding them together with a soft vinyl chloride laminated strip film interposed. (bridge processing) is adopted. However, in the currently practiced bridging process, for example, the width of the upper roller electrode of a high-frequency sewing machine bonding machine is as narrow as 3 to 10 mm, so it is impossible to bridge two laminated films at once. For this reason, a method has been adopted in which a flexible vinyl chloride resin strip film is first heat-welded to the vinyl chloride resin layer of one soft vinyl chloride laminated film, and then the other soft vinyl chloride laminated film is bridge-processed. There is. This method has the disadvantage that processing efficiency is poor because heat welding is performed twice, and when heat welding is performed for the first time, flare tends to occur in the welded part of the soft vinyl chloride resin strip film, making it difficult to perform bridge processing on the other side. There is also. Moreover, compared to the upper roller electrode of the high-frequency sewing machine adhesive processing machine,
Because the soft vinyl chloride resin strip film is adhesively processed with a fairly wide width, unwelded parts remain on the soft vinyl chloride resin strip film, and these parts may be exposed to water droplets or This causes dust to accumulate, resulting in a decrease in anti-fog or dust-proof properties due to extraction of the anti-fog agent or accumulation of dust. As described above, there are many problems with the width joints performed by the conventional bridge processing method, and no satisfactory solution has yet been found. "Problems to be Solved by the Invention" The present inventors have developed a method using a soft vinyl chloride resin film laminated with a resin that cannot be processed by high-frequency welding as a base layer between a pair of roller electrodes of a high-frequency welding machine such as a high-frequency sewing machine. After intensive study on an improved method for bridge welding composite films, we found that by widening the width of the pair of roller electrodes, and making one of the rollers at least 18 mm or more wide, and making the other wider, we found that The inventors discovered that the composite films described above can be bridged and completed the present invention. That is, an object of the present invention is to provide an improved method for bridging composite films each having a base layer of a vinyl chloride resin film laminated with resins that cannot be subjected to high-frequency welding. "Means for Solving the Invention" Therefore, the gist of the present invention is as follows. The ends of the two composite films are butted against each other so that the base layer is on the same surface, and a soft vinyl chloride resin strip film is overlaid on this abutting surface, and a width seam is processed using a high-frequency welding machine. In the method, the abutment is performed between the pair of roller electrodes of a high frequency welding machine equipped with a pair of roller electrodes, one of which has a width of at least 18 mm and the other of which has a width greater than this. A width joining processing method characterized by welding a base layer of a portion and a band-shaped film having a width slightly wider than the width of one of the roller electrodes at the same time in a bridge shape. (2) The width splicing method according to claim 1, wherein the flexible vinyl chloride resin strip film has a width 2 to 5 mm wider than the narrow roller electrode. The method of the present invention will be explained in detail. The vinyl chloride resin film that serves as the base layer of the composite film used in the method of the present invention has a composition mainly composed of a vinyl chloride resin, a plasticizer, and a stabilizer, and optionally an antifogging agent, a UV absorber, and an antioxidant. The polyvinyl chloride resin may contain various additives that can be incorporated into the vinyl chloride resin, such as additives, processing aids, lubricants, antistatic agents, antifungal agents, and antialgal agents. Vinyl chloride resin is
It is produced from vinyl chloride or a mixture of vinyl chloride and a monomer copolymerizable therewith by methods such as suspension polymerization, emulsion polymerization, fine suspension polymerization, and bulk polymerization. Other resins that cannot be high-frequency welded to vinyl chloride resins include acrylic ester resins such as polymethyl acrylate, polyethyl acrylate, polymethyl methacrylate, and polyethyl methacrylate, polyvinylidene fluoride, and vinylidene fluoride. and copolymers with monomers that can be copolymerized therewith, vinylidene fluoride resins such as polymer alloys of these resins and acrylic acid ester resins, low density polyethylene, linear low density polyethylene, ethylene-acetic acid. Examples include olefin resins such as vinyl copolymers, ethylene-acrylic acid ester copolymers, and ionomer resins. In order to produce a composite film, for example, each film is produced from a composition containing the above-mentioned vinyl chloride resin as a main component or another resin, and these films are bonded via an adhesive. For example, a method of coating a film with a solution of an acrylic ester resin, a method of coextruding a vinyl chloride resin composition and another resin with or without an adhesive, or one of the films, for example, a vinyl chloride resin film. Various methods are employed, such as a method of laminating while extruding another resin with or without an adhesive. In addition, the vinyl chloride resin strip film used in the method of the present invention is a film manufactured from the same composition as the vinyl chloride resin composition constituting the base layer.
As will be described later, the film is cut into an appropriate width, preferably 2 to 5 mm wider than the roller electrode width, and used as a strip-shaped film. The high frequency welding machine used in the method of the present invention is equipped with a pair of roller electrodes, and the width of one of the roller electrodes must be at least 18 mm and narrower than the flexible vinyl chloride resin strip film, and the width of the other roller electrode must be at least 18 mm. The width of the roller needs to be wider than the width of the one roller. One roller electrode width, for example, the upper roller electrode width
If it is smaller than 18 mm, it is necessary to increase the voltage of the high-frequency welding machine to obtain the required adhesive strength per unit, and if one of the composite films loosens or bends during welding, bridge processing must be started once. If this occurs, the welded part may meander, the width of the welded part becomes narrow, sparks may occur, and areas with weak tensile strength etc. are created, which causes practical problems. Also,
Even if the width of the upper roller electrode is 18 mm or more, if the width of the flexible vinyl chloride resin strip film is narrower than the width of the upper roller electrode, the tensile strength, etc. at the end of the weld will tend to become extremely weak due to fpark, etc. be. Therefore, it is preferable that the width of the flexible vinyl chloride resin strip film is 2 to 5 mm wider than the width of the upper roller electrode. If the width of the strip film is not 2 mm or more wider than the roller electrode width, it will easily come off from the roller electrode during welding, causing sparks and weakening the strength as described above. on the other hand,
If the width of the film strip is 5 mm or more wider than the width of the roller electrode, unwelded areas will occur, and the accumulation of water droplets and dust will likely adversely affect the anti-fog and dust-proof properties. Furthermore, if the width of the other roller electrode, for example the width of the lower roller electrode, is narrower than the soft vinyl chloride resin band film, the band film tends to be held incompletely, causing meandering or sparks. Therefore, it is desirable that the width of the lower roller electrode is larger than the width of the strip film. To carry out the method of the present invention, composite films each having a base layer of a vinyl chloride resin film laminated with another resin that cannot be subjected to high frequency welding are butted together so that the vinyl chloride resin film layers are on the same surface, and then After a soft vinyl chloride resin strip film is superimposed on the abutting surfaces of the vinyl chloride resin layer film, it is sandwiched between a pair of roller electrodes, and the base layer and the strip film are welded at once in a bridge shape, and a width splicing process is performed. conduct. It is desirable that the abutment interval between the ends of the composite film be in the range of 0 to 2 mm. If this interval becomes wide, for example, when used outdoors as an agricultural film, dust particles tend to adhere to portions of the strip-shaped film, which tends to reduce the dustproof properties. "Effects of the Invention" According to the width joint processing (bridge processing) method of the present invention, the following effects are achieved, and its industrial utility value is extremely large. One roller electrode used in the method of the present invention, for example, the upper roller electrode width is 18 mm or more and narrower than the width of the flexible vinyl chloride resin strip film, and the other roller electrode, for example, the lower roller electrode width is smaller than the width of the flexible vinyl chloride resin strip film. By widening the width, bridge processing can be performed at one time, and problems with the strength and quality (anti-fog, dustproof, etc.) of the welded part can be solved.The surface is made of soft vinyl chloride resin and the back side is made of soft vinyl chloride resin It is most suitable as a width splicing method for agricultural film, which is formed from a resin that cannot be welded by high frequency, and whose front and back surfaces cannot be simply welded by high frequency. "Examples" Next, the method of the present invention will be explained in detail based on Examples, but the present invention is not limited to the following examples unless the gist thereof is exceeded. (Film Preparation Example) 1 Composite film: A composite film in which a thin film of vinylidene fluoride resin was laminated on the surface of a soft vinyl chloride resin film via an adhesive layer was prepared by the following method. Pellet A; Vinyl chloride resin (PVC) composition (parts by weight) Polyvinyl chloride (average degree of polymerization = 1050) 100 Di-2-ethylhexyl phthalate (DOP)
47 Tricresyl phosphate (TCP) 5 Epoxidized soybean oil 3 Sorbitan monostearate (antifogging agent) 2 Benzotriazole ultraviolet absorber 0.1 Barium-zinc liquid stabilizer 1 Barium-zinc powder stabilizer 0.5 Bisamide 0.5 Above The composition components were mixed using a Henschel mixer, cooled, and then kneaded using a co-kneader manufactured by Buss to obtain pellets A that were extruded at a temperature of 170°C. Pellet B: Pellets of acrylic acid ester resin (manufactured by Mitsubishi Rayon Co., Ltd., trade name: ACRYPET MF) were used as pellets for the adhesive layer. Pellet C: Vinylidene fluoride resin (manufactured by Pennwalt, trade name: KYNAR)
1120 pellets were used. The pellets A, B, and C were melted and fed to a composite T-die for three-layer coextrusion using separate extruders, respectively. Pellet A was extruded at 180℃ using a 65φ extruder, pellet B was extruded at 250℃ using a 40φ extruder, pellet C was extruded at 250℃ using a 40φ extruder, and pellet C was extruded at 250℃ using a 40φ extruder. A molten film consisting of three layers sandwiching a resin layer based on pellets B was formed by cooling the film, which was guided onto a casting roll at 50°C placed close to the die, and a layer based on pellets A (chloride) was formed. The thickness of the layer based on pellet B (vinyl resin film) is 80μ, and the thickness of the layer based on pellet B (acrylic ester resin adhesive) is
10μ, the thickness of the layer based on pellet C (vinylidene fluoride resin) is 10μ, width 1000mm, length
A 50 m roll of composite film was obtained. 2. Composite film: A composite film in which a thin polyethylene film was laminated on the surface of a soft vinyl chloride film via an adhesive layer was prepared in the following manner. Pellet D: PVC composition (parts by weight) Polyvinyl chloride (=1300) 100 Plasticizer DOP 45 Tricresidyl phosphate (TCP) 5 Epoxy plasticizer (epichlorohydrin)
Condensate of bisphenol A, molecular weight 380) 3 Stabilizer Barium-zinc composite stabilizer 1.5 Barium stearate 0.5 Zinc stearate 0.5 Bisamide 0.5 Antifog agent (sorbitan monostearate) 2.0 Benzotriazole UV absorber 0.1 Above Mix the composition in a Henschel mixer,
After cooling, the mixture was kneaded using a co-kneader manufactured by Buss and extruded at a temperature of 170°C to obtain pellets D. Pellet E: Ethylene-vinyl acetate copolymer (EVA) (commercial product) EVA pellets with a vinyl acetate content of 28 wt% and a melt index of 7 g/10 min were used. Pellet F: Polyethylene (commercial product) Polyethylene pellets having a density of 0.918 g/cm ³ and a melt index of 12 g/10 min were used. Pellet D was extruded using a 65φ extruder, pellet E was extruded using a 40φ extruder, and pellet F was extruded using a 40φ extruder at 180°C, and then fed to a composite T-die for three-layer coextrusion. A molten film consisting of three layers was formed, and the film was cooled by being guided onto a 50°C casting roll placed close to the die. 14μ
A composite film with a width of 1000 mm and a length of 50 m was obtained. 3. Soft vinyl chloride resin strip film: Commercially available Noviace (100μ) manufactured by Mitsubishi Kasei Vinyl Co., Ltd. was cut into a film width of 12 mm to 20 mm, and used as a soft vinyl chloride resin strip film. Example 1 Upper roller electrode width 18 mm, lower roller electrode width
Using a high frequency sewing machine adhesive processing machine (model KL-1000 manufactured by Nippon Koshuha Co., Ltd.) with a 30 mm diameter, set two rolls of composite film on their respective feed roll supports, and then A flexible vinyl chloride resin strip film with a width of 20 mm was placed on the vinyl chloride resin surface (below), and width splicing was performed under the conditions of a roller electrode speed of 10 m/min, a voltage of 100 V, and a matching scale of 60. As a result, there was no meandering or sparking, there were no unwelded parts in the welded parts, and the strength was sufficient. Adhesive strength and anti-fog durability are shown in Table 1. Example 2 A composite film was used in place of the composite film used in Example 1, and width splicing was performed in the same manner as in Example 1. As a result, there was no meandering or sparking, there were no unwelded parts in the welded parts, and the strength was sufficient. Adhesive strength and anti-fogging durability are also listed in Table 1. Example 3 Width splicing was carried out in the same manner as in Example 1, except that the flexible vinyl chloride resin strip film in Example 1 was changed to 28 mm. There was no meandering or sparks, and the strength was sufficient. The test results for adhesive strength and anti-fog durability are shown in Table 1. Comparative Example 1 The width of the upper roller electrode used in Example 1 was 10 mm.
Width splicing was performed in the same manner as in Example 1, except that the width of the flexible vinyl chloride resin strip film was changed to 12 mm, and the voltage was changed to 130 V. As a result, the welded area between the composite film and the strip film was so narrow that adhesive strength for practical use could not be obtained. Comparative Example 2 The width of the soft vinyl chloride strip film of Example 1 was
Change to 16mm and change the voltage of the high frequency sewing machine adhesive processing machine.
Width joint processing was performed in the same manner as in Example 1, except that the voltage was changed to 110V. As a result, sparks were generated intermittently between the upper and lower roller electrodes, making it impossible to satisfactorily perform width joint processing. In addition, the strength of the welded end was poor. Comparative Example 3 Width joining was carried out in the same manner as in Example 1, except that the width of the lower roller electrode of the high-frequency sewing machine used in Example 1 was changed to 18 mm. As a result, it meandered and occasionally sparked, making it impossible to perform a satisfactory width joint.

[Table] The test method was as follows. 1 Adhesive Part Strength Test Method Using a dumbbell for measuring tensile cutting load shown in JIS-K6732, four test pieces were prepared so that the welded part was in the center of the test piece. The tensile cutting load of this test piece was measured using a chopper with a pulling speed of 200 mm/min. The average value of the four pieces was shown as the adhesive strength. 2 Anti-fogging durability test method The product was expanded in October 1959 to a single-roof type house with a width of 2 m and a depth of 10 m, with a roof slope of 30 degrees, so that the welded part was horizontal to 1/3 from the bottom of the roof surface. The droplet rising phenomenon was observed every three months. The anti-fogging durability was evaluated by the length of the droplet (droplet part). The smaller the value, the better the anti-fog durability.

Claims (1)

[Scope of Claims] 1 Composite films each having a vinyl chloride resin film as a base layer, which is a vinyl chloride resin film laminated with another resin that cannot be subjected to high-frequency welding, so that the base layers are flush with each other at the ends thereof. In this method, one side of the roller electrode has a width of at least 18 mm and the other side has a width of at least 18 mm. In a high-frequency welding machine equipped with a pair of roller electrodes having a width larger than this, between the pair of roller electrodes, a band-like shape having a width slightly wider than the base layer of the abutting part and the width of the one roller electrode is formed. A width joint processing method characterized by welding films together in a bridge shape. 2. The width joining method according to claim 1, wherein the flexible vinyl chloride resin strip film has a width 2 to 5 mm wider than the narrow roller electrode.