Antistatic tarpaulin and manufacturing method thereof

Abstract

To provide a tarpaulin for flexible container bag, which is excellent in antistatic property and has explosion-proof property, and also to provide a manufacturing method thereof.SOLUTION: A tarpaulin constitutes a section of "ethylenic copolymer resin surface layer / mesh fabric / ethylene copolymer resin rear surface conductive layer" or a section of "ethylenic copolymer resin surface layer / mesh fabric / ethylene copolymer resin intermediate layer / ethylene copolymer resin rear surface conductive layer". The antistatic tarpaulin includes composite conductor in the ethylene copolymer resin rear surface conductive layer. The composite conductor consists of conductive powder and conductive liquid compound. A portion or whole of the conductive liquid compound is absorbed and carried by the conductive powder. The conductive powder is acetylene black alone or combination of acetylene black and oil furnace carbon black. The conductive liquid compound is ion pair of cation and anion.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tarpaulin base fabric used for manufacturing flexible container bags and a manufacturing method thereof, and particularly relates to a tarpaulin having antistatic properties and further explosion-proof properties, and a manufacturing method thereof.

Background Art

[0002] Flexible container bags are of cylindrical or square prism shapes, with a filling port at the ceiling part and a discharge port at the bottom floor part. They are large containers that can freely seal and release the filling port and the discharge port. An empty flexible container bag can be folded to reduce its volume, and it is easy to handle. Generally, these flexible container bags are used for storing and transporting food raw materials such as flour, rice, wheat, soybeans, adzuki beans, sesame seeds, sugar, and salt, and industrial materials such as resin pellets of polyethylene and polypropylene, vinyl chloride resin pellets, and calcium carbonate powder. As the tarpaulin base fabric used for these flexible container bags, a flexible sheet in which an open-weave fabric is used as a core material and ethylene-vinyl acetate copolymer resin layers are laminated on both sides thereof is used. The reasons for using flexible container bags made of ethylene-vinyl acetate copolymer resin are its light weight (20% - 30% lighter than those made of soft vinyl chloride resin), chemical stability (less likely to be altered by the acidity or alkalinity of the filling material), safety (the filling material is not contaminated by stabilizers, plasticizers, etc.), high-frequency adhesion, and printability.

[0003] However, flexible containers made of ethylene-vinyl acetate copolymer resin are prone to static electricity generation due to friction. Especially when discharging resin pellets such as polyethylene and polypropylene, or rice (free fall through the opening at the bottom of the flexible container bag), the resin pellets become charged due to the friction between the resin pellets and the inner wall of the flexible container bag, and the resin pellets and rice grains electrostatically adhere to the inner wall of the flexible container bag, requiring laborious removal work. Depending on the surrounding environment, it can cause electrostatic fires, and furthermore, dust such as flour and calcium carbonate during powder discharge has a risk of inducing dust explosions. Therefore, an explosion-proof flexible container bag with antistatic performance is essential. These include flexible containers containing a polyolefin resin layer compounded with conductive carbon black (Patent Document 1), and terpolymers composed of a resin layer containing 15 to 50 parts by mass of a polymer-type permanent antistatic agent with respect to 100 parts by mass of a resin component containing at least 10% by mass of an unsaturated ester unit (Patent Document 2), etc. are known. However, when using the conductive carbon black of Patent Document 1, there is a possibility of a dangerous accident in which an energized spark (ignition) occurs during high-frequency welding, causing charred holes in the terpolymer. The blending of 15 to 50 parts by mass of the polymer-type permanent antistatic agent (thermoplastic resin) in Patent Document 2 has an adverse effect on the physical properties of the polyolefin resin and also has an adverse effect on the high-frequency weldability. Therefore, there has not yet been a terpolymer base fabric with excellent antistatic properties for manufacturing a flexible container bag (JIS C61340 4-4) that has sufficient antistatic properties, safe high-frequency weldability, and further explosion-proof properties.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a tarpaulin for a flexible container bag that has excellent antistatic properties and further has explosion-proof properties, and a method for manufacturing the same.

Means for Solving the Problems

[0006] As a result of repeated considerations and examinations in view of such points, as a tarpaulin made of an ethylene-based copolymer resin, a composite conductor composed of a conductive powder and a conductive liquid compound is included in the back surface layer, and part or all of this conductive liquid compound is adsorbed and supported by the conductive powder. By doing so, it has been found that the obtained tarpaulin has excellent antistatic properties and further has explosion-proof properties, and the present invention has been completed.

[0007] That is, the antistatic tarpaulin of the present invention is a tarpaulin having a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin back conductive layer" or a tarpaulin having a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", wherein the ethylene-based copolymer resin back conductive layer contains a composite conductor, and this composite conductor is composed of a conductive powder and a conductive liquid compound, and a part or all of this conductive liquid compound is adsorbed and supported on the conductive powder, and the conductive powder is acetylene black alone or a combination of acetylene black and oil furnace carbon black, and the conductive liquid compound is preferably an ion pair of a cation and an anion. By adsorbing and supporting the conductive liquid compound on the conductive powder, a composite conductor in which the conductive powder particles are more densely adhered can be obtained. In the case of a tarpaulin having a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin back conductive layer", the content of the conductive powder is 2.5 to 10 parts by mass with respect to 100 parts by mass of the ethylene-based copolymer resin constituting the ethylene-based copolymer resin conductive layer, and 11 to 20 parts by mass at the explosion-proof level. In the case of a tarpaulin having a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", the content of the conductive powder is 5 to 20 parts by mass with respect to 100 parts by mass of the ethylene-based copolymer resin constituting the ethylene-based copolymer resin conductive layer when the thickness of the conductive layer is reduced by nearly half, and 21 to 30 parts by mass at the explosion-proof level. By means of the fine particles of the conductive powder (acetylene black, oil furnace carbon black), an antistatic tarpaulin capable of exhibiting antistatic properties and enabling safe high-frequency welding that is less likely to cause spark ignition can be obtained. Using these tarpaulins as the base fabric, it is possible to provide a flexible container bag with excellent antistatic properties and further a flexible container bag with explosion-proof properties.

[0008] The antistatic tarpolin of the present invention is such that the cation is one selected from imidazolium-based, imidazolinium-based, pyridinium-based, pyrazolium-based, pyrrolidinium-based, piperidinium-based, quaternary ammonium-based, phosphonium-based, sulfonium-based, and the anion is a chemical formula, BF4 - , PF6 - , TaF6 - , NbF6 - , SiF6 - , AlF4 - , AlCl4 - , NO2 - , NO3 - , F - , Cl - , Br - , I - , CN - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , CF3SO2 - , CF3SO4 - , (CF3SO2)2N - , p-CH3PhSO3 - , CH3CO2 - , HSO4 - , HSO3 - , CH3SO3 - , CH3SO4 - , CF3SO3 - , (CF3SO2)3C - , C3F7CO2 - , C4F9SO3 - , (C2F5SO2)2N - , (CF3SO2)(CF3CO)N - , (CN)2N - , and it is preferably one selected from. The content of the conductive liquid compound is in a blending amount of 20 to 100% by mass with respect to the blending amount of the conductive powder. As a result, the conductive liquid compound can penetrate into the conductive powder structure, suppressing the loss of antistatic performance due to the lubricant. By using this tarpolin, it is possible to obtain an antistatic flexible container bag that is safely high-frequency welded, and further an explosion-proof flexible container bag.

[0009] The antistatic tarp of the present invention is mainly composed of the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin intermediate layer, and the ethylene-based copolymer resin back conductive layer, and this ethylene-based copolymer resin is an ethylene-vinyl acetate copolymer resin, an ethylene-acrylic acid copolymer resin, an ethylene-acrylic acid ester copolymer resin, an ethylene-methacrylic acid copolymer resin, or an ethylene-methacrylic acid ester copolymer resin. It is preferably one or more selected from the group consisting of these, and the content of ethylene units is preferably 65 to 85% by mass. By having 15 to 35% by mass of a polar component, high-frequency welding is enabled.

[0010] It is preferable that the antistatic tarp of the present invention contains conductive fiber yarns in a part of the open-weave fabric. This can improve the antistatic property and explosion-proof property.

[0011] The manufacturing method of the antistatic tarp of the present invention is a method for manufacturing a tarp having a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin back conductive layer" or a tarp having a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", wherein the ethylene-based copolymer resin back conductive layer contains a composite conductor composed of a conductive powder and a conductive liquid compound, and in the production of the ethylene-based copolymer resin back conductive layer or in the preparation stage of the production, a part or all of the conductive liquid compound is adsorbed and supported on the conductive powder to be processed into the composite conductor. The method includes a step of molding an ethylene-based copolymer resin layer film containing this composite conductor and laminating it on the open-weave fabric or the ethylene-based copolymer resin intermediate layer. It is preferable that the conductive powder is acetylene black alone or a combination of acetylene black and oil furnace carbon black, and the conductive liquid compound is an ion pair of a cation and an anion.

[0012] The method for manufacturing the antistatic tarpolin of the present invention is such that the cation is one selected from imidazolium-based, imidazolinium-based, pyridinium-based, pyrazolium-based, pyrrolidinium-based, piperidinium-based, quaternary ammonium-based, phosphonium-based, sulfonium-based, and the anion is a chemical formula, BF4 - , PF6 - , TaF6 - , NbF6 - , SiF6 - , AlF4 - , AlCl4 - , NO2 - , NO3 - , F - , Cl - , Br - , I - , CN - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , CF3SO2 - , CF3SO4 - , (CF3SO2)2N - , p-CH3PhSO3 - , CH3CO2 - , HSO4 - , HSO3 - , CH3SO3 - , CH3SO4 - , CF3SO3 - , (CF3SO2)3C - , C3F7CO2 - , C4F9SO3 - , (C2F5SO2)2N - , (CF3SO2)(CF3CO)N - , (CN)2N - , and it is preferably one selected from them.

[0013] The method for manufacturing the antistatic tarpolin of the present invention preferably includes conductive fiber yarns in a part of the open-weave fabric.

Effects of the Invention

[0014] The present invention enables the provision of an antistatic tarpaulin having antistatic properties and further explosion-proof properties (JIS C61340 4-4), and a method for manufacturing the same.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0016] The antistatic tarpaulin of the present invention is a tarpaulin having a cross-section of "ethylene-based copolymer resin surface layer / open-mesh fabric / ethylene-based copolymer resin back conductive layer" or a tarpaulin having a cross-section of "ethylene-based copolymer resin surface layer / open-mesh fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", wherein the ethylene-based copolymer resin back conductive layer contains a composite conductor, and this composite conductor is composed of a conductive powder and a conductive liquid compound, and a part or all of this conductive liquid compound is adsorbed and supported on the conductive powder, and a part of the open-mesh fabric contains conductive fiber yarns. In these manufacturing methods, the ethylene-based copolymer resin back conductive layer contains a composite conductor composed of a conductive powder and a conductive liquid compound, and in the manufacturing of the ethylene-based copolymer resin back conductive layer or in the preparation stage of manufacturing, a part or all of the conductive liquid compound is adsorbed and supported on the conductive powder to be processed into a composite conductor, and a step of molding an ethylene-based copolymer resin layer film containing this composite conductor and laminating it on the open-mesh fabric or the ethylene-based copolymer resin intermediate layer is essential.

[0017] The open-mesh fabric used in the antistatic tarpaulin of the present invention has a porosity of 10 to 25% and a basis weight of 125 to 325 g / m woven by warp yarn groups and weft yarn groups. 2In this case, examples of the fabric structures for both the warp and weft yarn groups include plain weave, twill weave, crepe weave, imitation gauze weave, basket weave, etc. in which 15 to 30 multifilament yarns are arranged per inch. In particular, a plain woven fabric is preferable because it has an excellent balance of physical properties in the warp and weft directions of the tarpaulin. However, for the entire flexible container bag formed by three-dimensionally sewing a plurality of tarpaulin parts, triaxial fabrics, four-axis fabrics, etc. that can provide an even stress dispersion effect against internal pressure loads can also be used. The multifilament yarn is a twisted yarn with a fineness of 555 to 1665 dtex (twist number 100 to 300 turns / m), the filament has a fineness of 2.2 to 11 dtex, particularly 2.2 to 5.5 dtex, and the number of filaments is preferably 50 to 757, particularly 100 to 300. Here, the twisted yarn with a fineness of 555 dtex may be a combined twisted yarn of two 277 dtex twisted yarns, and further, the twisted yarn with a fineness of 1665 dtex may be a combined twisted yarn of three 277 dtex twisted yarns. Also, bulky yarns such as Taslan yarns and crimped yarns can be used as the multifilament yarn. These are used in combination with non-bulky multifilament yarns in a range of yarn number ratios of 1 (bulky):1 (non-bulky) to 1 (bulky):5 (non-bulky). When used as a partially bulky fabric, due to the anchor effect in which the filaments in the bulky part penetrate into the ethylene-based copolymer resin layer, the adhesion between the open-weave fabric and the ethylene-based copolymer resin layer increases, and as a result, the creep resistance of the joint of the flexible container bag improves and the quality becomes stable. Alternatively, a combined twisted yarn of a multifilament yarn and a bulky yarn can also obtain a similar anchor effect, but the effect may be insufficient due to the combined twisting. Taslan yarns are produced by a method of opening multifilaments in a high-pressure turbulent air flow to generate loop-shaped fluff. The degree of bulkiness (the swollen state of the yarn diameter is 1.2 to 1.6 times) can be variously adjusted by the overfeed rate, false twist number, dry heat setting temperature (near the softening temperature of the fiber), etc. Core-sheath type Taslan yarns with a bulky sheath part in a loop shape can also be used.The crimped yarn is obtained by subjecting a false-twisted multifilament yarn to dry heat setting, then forcibly untwisting the set twist and performing a bulk processing so that the curls are intertwined. The degree of crimp (the swollen state of the yarn diameter is 1.2 to 1.6 times) can be variously controlled by combinations such as the number of false twists, the dry heat setting temperature (near the softening temperature of the fiber or lower), the untwisting rate, the overfeed rate, the yarn take-up speed, the number of twists, the relaxation heat treatment temperature, and the like.

[0018] The fiber types of the yarns constituting the open-mesh fabric can include polypropylene fibers, polyethylene fibers, vinylon fibers, polyester (such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.) fibers, nylon fibers (such as 6-nylon, 6,6-nylon, 6,10-nylon, etc.), recycled fibers obtained by repolymerizing monomers obtained by depolymerizing these recycled fibers, etc., and two types of fiber types can be used as necessary. In particular, conductive carbon fibers or electroplated conductive fibers are used in a part of the multifilament yarn group and arranged in a stripe shape, preferably in a grid-like conductive network structure at a certain number interval to form a conductive structure with antistatic properties. A specific example of this is a case where polyester (polyethylene terephthalate) fibers are used for the main structure of the open-mesh fabric as multifilament yarns, and a part (n intervals: n is an integer from 1 to 100, for example, 24 or 49) of the multifilament yarns in the warp group and the weft group is replaced with conductive carbon fiber yarns, which is an aspect of enhancing the antistatic effect by a grid-like conductive network structure. At this time, the conductive carbon fiber yarn can be a two-layer structure yarn with a polyester fiber multifilament yarn as the core and a conductive carbon fiber yarn (or electroplated conductive fiber) as the sheath, or it can also be a blended yarn of a polyester fiber multifilament and a conductive carbon fiber (or electroplated conductive fiber). For the tarpaulin in these weaving specifications, it is essential to directly provide an ethylene-based copolymer resin back conductive layer on the open-mesh fabric to improve the antistatic property. Also, high-strength heat-resistant fiber yarns such as wholly aromatic polyester fibers (polyarylate fibers), wholly aromatic polyamide fibers (such as polyparaphenylene terephthalamide fibers, polyparabenzamide fibers, and copolyparaphenylene 3,4-oxydiphenylene terephthalamide fibers) can be used. These yarns can also be used to form a mode of significantly enhancing the tear prevention effect by replacing a part (n intervals: n is an integer) of the polyester (polyethylene terephthalate) fiber multifilament yarns in the warp group and / or the weft group with high-strength heat-resistant fiber yarns. It is also possible to use an open-mesh fabric in which conductive carbon fiber yarns and high-strength heat-resistant fiber yarns are used in combination and a part of the multifilament yarns is replaced with polyester (polyethylene terephthalate) fibers.For the eye-opening fabric used in the present invention, adhesive application, resin impregnation treatment, water repellent (waterproof) treatment, flame retardant treatment, etc. can be performed as necessary.

[0019] The ethylene-based copolymer resin surface layer and the ethylene-based copolymer resin back conductive layer used in the antistatic tarpaulin of the present invention are mainly composed of an ethylene-based copolymer resin, and their thickness is about 150 to 350 μm. It is preferable that the surface layer and the back conductive layer have the same thickness, but depending on the properties of the filler, the back conductive layer can be made thinner or thicker than the surface layer. In particular, by adopting a two-layer structure of "ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer" for the back resin layer, it is possible to densify the conductive powder and the conductive liquid compound in the thinner conductive layer, making it easier to meet the explosion-proof standards. This ethylene-based copolymer resin is selected from one or more of ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-acrylic acid ester copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-methacrylic acid ester copolymer resin, and preferably has an ethylene unit content of 65 to 85% by mass. By having 15 to 35% by mass of polar components such as vinyl acetate and (meth)acrylic acid, high-frequency welding is made possible. When the ethylene unit content exceeds 85% by mass, the high-frequency weldability deteriorates due to the small amount of polar components, and it becomes necessary to increase the energizing amperage. However, this high-output state may pose a danger to the operation. On the other hand, when the ethylene unit content is less than 70% by mass, the film strength of the ethylene-based copolymer resin surface layer and the ethylene-based copolymer resin back conductive layer decreases, and the wear resistance tends to deteriorate. As a means of improving the wear resistance of the ethylene-based copolymer resin surface layer and the ethylene-based copolymer resin back conductive layer, an ethylene-based copolymer resin surface layer and an ethylene-based copolymer resin conductive layer can be formed by blending the above ethylene-based copolymer resin with an ethylene-α-olefin copolymer resin (metallocene polyethylene). The blending amount of the ethylene-α-olefin copolymer resin is preferably within a range that maintains a content of 15 to 30% by mass of vinyl acetate, acrylic acid, acrylic acid ester, methacrylic acid, methacrylic acid ester, etc. in the ethylene-based copolymer resin surface layer and the ethylene-based copolymer resin back conductive layer and enables high-frequency welding.Also, the melt flow rate (MFR: 190 °C, load 2.16 kgf) of the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin intermediate layer, and the ethylene-based copolymer resin back conductive layer is preferably 0.5 to 5.0 g / 10 min, particularly preferably 1.0 to 3.5 g / 10 min. If the MFR is less than 0.5 g / 10 min, the texture of the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin intermediate layer, and the ethylene-based copolymer resin back conductive layer becomes hard, and the flexibility of the flexible container bag obtained is impaired. Also, if the MFR exceeds 5.0 g / 10 min, the heat resistance temperature of the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin intermediate layer, and the ethylene-based copolymer resin back conductive layer becomes low, deteriorating the heat resistance creep property of the joint (high-frequency welding part) of the flexible container bag obtained, and making it easy for bag breakage accidents to occur due to high-temperature fillers.

[0020] The ethylene-based copolymer resin back conductive layer contains conductive powder. As the conductive powder, acetylene black alone or a combination of acetylene black and oil furnace carbon black is used. In the case of a tarpulin constituting the cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin back conductive layer", the content is 2.5 to 10 parts by mass based on 100 parts by mass of the ethylene-based copolymer resin constituting the ethylene-based copolymer resin conductive layer, and 11 to 20 parts by mass at the explosion-proof level. In the case of a tarpulin constituting the cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", the content is 5 to 20 parts by mass based on 100 parts by mass of the ethylene-based copolymer resin constituting the ethylene-based copolymer resin conductive layer due to the thickness of the conductive layer being nearly halved, and 21 to 30 parts by mass at the explosion-proof level. The primary particles of these conductive powders are particles with a particle diameter of 10 to 200 nm in which 1000 to 2000 crystallites, each composed of 3 to 5 layers of plates with 30 to 40 carbon 6-membered rings bonded together, are aggregated. The conductive powder is a structure in which 20 to 100 of these primary particles are chemically and physically bonded. Acetylene black as such a conductive powder has a primary particle diameter of 20 to 50 nm and a BET specific surface area of 35 to 160 m 2 / g, a structure (pH 9 - 10) with a DBP oil adsorption amount of 140 - 220 ml / 100 g. The oil furnace carbon black has a primary particle size of 10 - 100 nm and a BET specific surface area of 50 - 300 m 2 / g, a structure (pH 7 - 8) with a DBP oil adsorption amount of 40 - 200 ml / 100 g, and in particular, by satisfying the characteristic of a DBP oil adsorption amount of 40 - 220 ml / 100 g, it is possible to adsorb and carry part or all of the conductive liquid compound used in combination. The reason why acetylene black is preferred as the conductive powder in the present invention is that due to its high - purity graphite structure and long - chain structure (aggregate, agglomerate) of the structure, the sudden increase in electrical resistance (PTC phenomenon) associated with the breakage of the chain structure due to the temperature rise during high - frequency welding is less likely to occur. This is because it is less likely to cause spark ignition during the high - frequency welding of the explosion - proof flexible container bag. Therefore, the combined use of acetylene black and oil furnace carbon black is such that the mass ratio of acetylene black:oil furnace carbon black is 10:1 - 1:1. If the amount of the conductive powder is less than 2.5 parts by mass (less than 5 parts by mass in the embodiment with an intermediate layer), sufficient antistatic property (explosion - proof property) cannot be obtained, and if it exceeds 10 parts by mass (exceeds 20 parts by mass in the embodiment with an intermediate layer), spark ignition may occur during high - frequency welding. Acetylene black and oil furnace carbon black are preferably used as pigment pellets highly dispersed in an ethylene - based (copolymer) resin from the viewpoints of uniform dispersibility and stabilization of conductivity. This pigment pellet also contains a conductive liquid compound at the same time. By adsorbing and carrying the conductive liquid compound in the conductive powder structure to form a composite conductor in which the conductive powder particles are in close contact, a higher level of antistatic property (explosion - proof property) can be obtained. At this time, it is preferable to adsorb the conductive liquid compound in the structure of the conductive powder and form a composite conductor paste with closer contact between the conductive powder particles.

[0021] The conductive liquid compound adsorbed and supported on the conductive powder is formed by an ion pair of a cation and an anion, and the cation is an imidazolium-based (such as 1-butyl-3-methylimidazolium, 1-allyl-3-methylimidazolium, 1-butyl-2,3-dimethylimidazolium, etc.), imidazolinium-based (such as 1-butyl-3-methylimidazolinium, 1-allyl-3-methylimidazolinium, 1-butyl-2,3-dimethylimidazolinium, etc.), pyridinium-based (such as 1-butylpyridinium, 1-ethylpyridinium, 1-butyl-4-methylpyridinium, etc.), pyrazolium-based (such as 1-butylpyrazolium, 1-ethylpyrazolium, 1-butyl-4-methylpyrazolium, etc.), pyrrolidinium-based (such as 1-butyl-1-methylpyrrolidinium, 1-methyl-1-propylpyrrolidinium, etc.), piperidinium-based (such as 1-butyl-1-methylpiperidinium, 1-methyl-1-propylpyrrolidinium, etc.), quaternary ammonium-based (such as amyltriethylammonium, butyltriethylammonium, benzyldimethylethylammonium, etc.), phosphonium-based (such as tetrabutylphosphonium, tributylmethylphosphonium, tributylhexylphosphonium, etc.), sulfonium-based (such as trimethylsulfonium, triethylsulfonium, tributylsulfonium, etc.), and is one selected from them. Also, the anion has the chemical formula BF4 - , PF6 - , TaF6 - , NbF6 - , SiF6 - , AlF4 - , AlCl4 - , NO2 - , NO3 - , F - , Cl - , Br - , I - , CN - , AsF6 - , SbF6 - , NbF6 - , TaF6 - , CF3SO2 - , CF3SO4 - , (CF3SO2)2N - , p-CH3PhSO3 - , CH3CO2- , HSO4 - , HSO3 - , CH3SO3 - , CH3SO4 - , CF3SO3 - , (CF3SO2)3C - , C3F7CO2 - , C4F9SO3 - , (C2F5SO2)2N - , (CF3SO2)(CF3CO)N - , (CN)2N - It is one selected from the group consisting of these. The blending amount of these conductive liquid compounds (ion pairs) is 20 to 100% by mass based on the blending amount of the conductive powder. By using the conductive powder and the conductive liquid compound in combination, particularly by forming a conductive composite (paste) in which the conductive liquid compound is adsorbed and supported in the structure of the conductive powder, excellent antistatic properties (explosion-proof properties) can be obtained. If the blending amount of the conductive liquid compound is less than 20% by mass, the amount of the conductive liquid compound penetrating into the conductive powder structure is insufficient, and the effect of suppressing the decrease in antistatic properties (explosion-proof properties) due to the penetration of the lubricant into the conductive powder structure may be insufficient. On the other hand, if the blending amount exceeds 100% by mass, the conductive liquid compound may bleed to the surface of the conductive layer on the back of the ethylene-based copolymer resin, contaminating the filling material in the flexible container bag.

[0022] Among the conductive liquid compounds, quaternary ammonium salts are particularly preferred. Specifically, (C2H5)5N + , (C3H7)4N + , (C4H9)4N + , (C5H 11 )4N + and other quaternary ammonium cations, and CF3SO4 - , CH3SO4 - , HSO4 - , CF3SO4 - , CH3SO3 - , HSO3 -Salts composed of anions containing sulfuric acid or sulfurous acid, such as, are included. Also, the four alkyl groups of the quaternary ammonium cation may be the same or different from each other. Among these, tetraalkylammonium hydrogen sulfates such as butyltriethylammonium and amyltriethylammonium are preferable, and tetrabutylammonium hydrogen sulfate [(C4H9)4N(HSO4)] is particularly preferable. These conductive liquid compounds are preferably adsorbed and supported on a conductive powder (acetylene black or a combination of acetylene black and oil furnace carbon black) in advance to make the space between the conductive powder particles more densely adhered, or granulated into a composite conductor (paste) or a concentrated pellet. This is preferable from the viewpoints of non-scattering property, dispersibility, and high antistatic property (explosion-proof property). The adsorption and support can be obtained by covering a specific amount of the conductive powder with a specific amount of the conductive liquid compound, stirring, and then allowing it to stand at normal temperature and pressure for several hours.

[0023] If necessary, by containing 3 to 20% by mass of synthetic amorphous silica in the ethylene-based copolymer resin surface layer and / or the ethylene-based copolymer resin intermediate layer, the high-frequency weldability can be improved, and further the heat-resistant creep property can be improved. Synthetic amorphous silica (silicon dioxide) is obtained by a wet method in which sodium silicate, a mineral acid (sulfuric acid), and salts are reacted in an aqueous solution. The silanol group (R 1 R 2 R 3Hydrous silica having water molecules hydrogen-bonded to Si-OH groups (wherein R is hydrogen, an alkyl group, etc.) and water molecules present as hydroxyl groups contained in the silanol groups themselves as bound water, with an average agglomeration particle size (by Coulter counter method) of 1 to 20 μm, preferably 2 to 10 μm, and a water content of 3 to 15% by mass, preferably 5 to 10% by mass. If the blending amount of synthetic amorphous silica is less than 3% by mass, the effect of improving heat-resistant creep properties becomes insufficient. If the blending amount exceeds 20% by mass, it may reduce the processability and wear resistance strength of the ethylene-based copolymer resin surface layer and the ethylene-based copolymer resin intermediate layer. A conductive liquid compound is adsorbed onto this synthetic amorphous silica in an amount of 10 to 50% by mass based on the mass of the synthetic amorphous silica, and the antistatic property (anti-explosion property) can be enhanced. Also, if necessary, the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin intermediate layer, and the ethylene-based copolymer resin back conductive layer can contain about 10% by mass of rubber such as EPDM and EPM to improve wear resistance and heat-resistant creep properties. Further, known additives such as stabilizers, fillers, coloring pigments, flame retardants, flame inhibitors, ultraviolet absorbers, light stabilizers, mildew inhibitors, antibacterial agents, antistatic agents, and crosslinking agents can be arbitrarily blended into the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin intermediate layer, and the ethylene-based copolymer resin back conductive layer.

[0024] The film for the ethylene-based copolymer resin surface layer and the ethylene-based copolymer resin back conductive layer is, for example, a film formed to a thickness of about 150 to 350 μm by a known method such as the T-die extrusion method or the calendar method, and is suitable for a flexible container bag. In particular, when the back resin layer has a two-layer structure of "ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", the thickness of these two layers is about 150 to 350 μm. The ethylene-based copolymer resin back conductive layer contains a composite conductor composed of a conductive powder and a conductive liquid compound. This composite conductor is preferably obtained by a process of adsorbing and supporting part or all of the conductive liquid compound on the conductive powder during the production of the ethylene-based copolymer resin back conductive layer or in the preparation stage of the production to process it into a composite conductor. Next, it is preferable to include a step of molding an ethylene-based copolymer resin layer film containing this composite conductor and laminating it on a mesh fabric or an ethylene-based copolymer resin intermediate layer. Specifically, the antistatic tarpolin that becomes the raw material of the flexible container bag is obtained by laminating these films on both sides of a mesh fabric. Using the pre-formed two-layer film for the front side and the back side (or the intermediate layer), it is passed through a laminator equipped with a metal hot roll / rubber roll and a heater, and the film is thermocompression bonded onto the mesh fabric in a state of being semi-molten and softened by heating to obtain a thickness of about 0.5 to 1.2 mm. In the embodiment including the ethylene-based copolymer resin intermediate layer, it is passed through the laminator again to laminate the ethylene-based copolymer resin back conductive layer on the ethylene-based copolymer resin intermediate layer to a thickness of about 0.5 to 1.2 mm. In these cases, the films on the front side and the back side (in some cases, a two-layer structure) partially form a thermal melting bridge through the voids of the mesh fabric, thereby increasing the adhesive force between the ethylene-based copolymer resin surface layer, the ethylene-based copolymer resin back conductive layer (or the ethylene-based copolymer resin intermediate layer) and the mesh fabric, and improving the heat-resistant creep property of the joint of the flexible container bag.

[0025] The heat welding and sewing of flexible container bags can be achieved by methods such as high-frequency welder fusion method, hot air fusion method, and ultrasonic fusion method. The surface resistance value of the inner surface conductive layer of the ethylene-based copolymer resin of the obtained antistatic tarpaulin is 10 5 Ω to 10 8 Ω, and particularly for explosion-proof properties, 10 3 Ω to 10 4 Ω is preferred. Also, in the antistatic flexible container bag, and further in the explosion-proof flexible container bag, the inner ethylene-based copolymer resin inner surface conductive layer, and furthermore the conductive fibers contained in the fabric base fabric are connected to the ground wire, and it is essential to have an attached ground wire that protrudes outside the container bag, thereby ensuring explosion-proof properties.

[0026] Example The present invention will be further described with the following examples and comparative examples, but the present invention is not limited to the scope of these examples. 1) High-frequency fusion property The lower end of the tarpaulin and the upper end of the other tarpaulin were overlapped in parallel with a width of 9 cm, and a high-frequency welder (YTO-8A type manufactured by Yamamoto Vinita Co., Ltd.: high-frequency output 8 KW) equipped with a 9 cm width × 30 cm length welding bar (concave-convex tooth shape: convex part height 0.5 mm, 9 straight lines per inch, concave part depth 0.5 mm, 9 straight lines per inch) was used to high-frequency weld and join the tarpaulin with an anode current of 0.8 A (energization for 5 seconds / cooling for 5 seconds), and the presence or absence of spark generation was confirmed. 2) Antistatic property of tarpolin: Surface resistivity (conforming to JIS K7194) After leaving the film material piece standing for 24 hours at 23°C and a relative humidity of 50% RH, the surface resistivity was measured 3 times using the following resistivity meter (conforming to JIS K7194), and the average value was taken as the surface resistivity. The surface resistivity depends on the blending amount of the conductive material (conductive powder, conductive liquid compound), and the higher the blending amount, the more the explosion-proof level can be reached. A) High resistance · Resistivity meter "Hi Rester UP MCP-HT800 (range 103 ~10 14 Ω) B) Low resistance · resistivity meter Manufactured by Mitsubishi Chemical Analytech Co., Ltd., "Roresta GX MCP-T700 (range 10 -4 ~10 7 Ω)」

[0027] [Example 1] <Open-mesh fabric 1> Using a multifilament yarn (M) obtained by twisting 832 dtex (144 filaments) of 750-denier polyester (polyethylene terephthalate) at 150 T / m in S twist, a plain weave fabric with a void ratio of 20% and a mass of 136 g / m 2 was woven <Antistatic tarpolin 1> Ethylene-based copolymer resin surface layer: By the process of calendering and molding [Formulation 1] into a film (blue) with a thickness of 0.26 mm Ethylene-based copolymer resin back conductive layer: By the process of calendering and molding [Formulation 2] into a film (black) with a thickness of 0.22 mm A film (blue) of the ethylene-based copolymer resin surface layer was thermocompression bonded to the surface of the open-mesh fabric 1, and a film (black) of the ethylene-based copolymer resin back conductive layer was thermocompression bonded to the back surface between the metal hot roll / rubber roll at 150 °C of a laminator, bridging a part of the ethylene-based copolymer resin surface layer and a part of the ethylene-based copolymer resin back conductive layer through 20% of the voids of the open-mesh fabric 1, to obtain a tarpolin 1 with a thickness of 0.67 mm and a mass of 649 g / m 2 The obtained tarpolin 1 was excellent in antistatic properties. [Formulation 1] Ethylene-based copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (Vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Titanium oxide (white pigment) 1.4 parts by mass Phthalocyanine blue (blue pigment) 2 parts by mass [Composition 2] Ethylene copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (Vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle diameter 35 nm, specific surface area 69 m 2 / g, DBP absorption 160 ml / 100 g) 8 parts by mass Tetrabutylammonium hydrogen sulfate (quaternary ammonium-based conductive liquid compound ((C4H9)4N·(HSO4))) 4 parts by mass ※ Use a composite conductor in which 4 parts by mass of tetrabutylammonium hydrogen sulfate is adsorbed and supported on 8 parts by mass of acetylene black (acetylene B) conductive powder (including the step of stirring the conductive liquid compound on the conductive powder and allowing it to stand at room temperature for 3 hours, and the following Examples 2 to 8 also include the same steps)

[0028] [Example 2] [Antistatic tarp 2] Ethylene copolymer resin surface layer: Calender roll and mold [Composition 1] into a 0.28 mm thick film (blue), and also calender roll and mold the ethylene copolymer resin back conductive layer: [Composition 3] into a 0.28 mm thick film (black). In the same manner as in Example 1, a tarp 2 with a thickness of 0.67 mm and a mass of 649 g / m 2 was obtained. The obtained tarp 2 was excellent in antistatic properties. [Composition 3] Ethylene copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (Vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle diameter 35 nm, specific surface area 69 m 2 / g, DBP absorption 160 ml / 100 g) 5 parts by mass​​ Oil furnace carbon black (conductive powder: particle size 40 nm, specific surface area 58 m 2 / g, DBP absorption 168 ml / 100 g) 3 parts by mass Triethylsulfonium bis(trifluoromethanesulfonyl)imide (sulfonium -based conductive liquid compound: [(CH2CH3)3S·(CF3SO2)2 N]) 4 parts by mass ※ Use a composite conductor in which 5 parts by mass of acetylene black conductive powder and 3 parts by mass of oil furnace carbon black (F carbon B) conductive powder are adsorbed and supported with 4 parts by mass of triethylsulfonium bis (trifluoromethanesulfonyl)imide (trifluoromethanesulfonyl)imide body

[0029] [Example 3] <Open-weave fabric 2> Using the same multifilament yarn (M) as in Example 1 and the following carbon fiber yarn (E), the warp group arrangement and the weft group arrangement are such that the mixing ratio of 24 multifilament yarns (M): 1 carbon fiber yarn (E), "(M) 24 / (E) 1): E number 4%" is repeated, and the weaving density is 20 warp groups per inch and 19 weft groups per inch for plain weave, with a porosity of 20% and a mass of 136 g / m 2 of open-weave fabric 2. The carbon fiber yarn is a multifilament yarn (E) with 1188 denier (1320 dtex: 2000 filaments) twisted at 160 T / m in S twist, and its arrangement is the 1st, 25th, 50th, 75th, 100th,... in both the warp group and the weft group. <Antistatic tarp 3> Ethylene copolymer resin surface layer: [Formulation 1] is calendered and molded into a film (blue) with a thickness of 0.28 mm, and the ethylene copolymer resin back conductive layer: [Formulation 4] is calendered and molded into a film (black) with a thickness of 0.28 mm. In the same manner as in Example 1, using open-weave fabric 3 as the base material, with a thickness of 0.67 mm and a mass of 649 g / m 2The terpolymer 3 was obtained. The obtained terpolymer 3 was excellent in explosion-proof performance due to the conductivity of the carbon fiber yarn (E) of the open-mesh fabric 2 and the effect of the back conductive layer (containing a composite conductor at a high concentration) in contact with the carbon fiber yarn (E). [Formulation 4] Ethylene copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (Vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle diameter 35 nm, specific surface area 69 m 2 / g, DBP absorption 160 ml / 100 g) 16 parts by mass Butylpyridinium hexafluorophosphate (pyridinium-based conductive liquid compound: [CH3(CH2)3N·PF6]) 8 parts by mass ※ A composite conductor in which 4 parts by mass of butylpyridinium hexafluorophosphate is adsorbed and supported on 8 parts by mass of acetylene black conductive powder is used

[0030] [Example 4] [Open-mesh fabric 3] Using the same multifilament yarn (M) as in Example 1 and the carbon fiber yarn (E) of Example 3, the warp group arrangement and the weft group arrangement are such that the mixing ratio of 49 multifilament yarns (M): 1 carbon fiber yarn (E), "(M) 49 / (E) 1): E number 2%" is repeated, and the weaving density is 20 warp groups per inch and 19 weft groups per inch for plain weaving, with a porosity of 20% and a mass of 136 g / m 2 of the open-mesh fabric 2. The arrangement of the carbon fiber yarns is the 1st, 50th, 100th, 150th,... in both the warp group and the weft group. [Antistatic terpolymer 4] Ethylene-based copolymer resin surface layer: The [Formulation 1] was calendered and molded into a film (blue) with a thickness of 0.28 mm. Also, the ethylene-based copolymer resin back conductive layer: [Formulation 5] was calendered and molded into a film (black) with a thickness of 0.28 mm. In the same manner as in Example 1, a tarpolin 4 with a thickness of 0.67 mm and a mass of 649 g / m was obtained using the open-weave fabric 4 as the base material. 2 The obtained tarpolin 4 was excellent in explosion-proof properties due to the conductivity of the carbon fiber yarn (E) of the open-weave fabric 3 and the effect of the back conductive layer (containing a high-concentration composite conductor) in contact with the carbon fiber yarn (E). 〔Formulation 5〕Ethylene-based copolymer resin composition Ethylene-methyl methacrylate copolymer resin (EMMA) (Methyl methacrylate content 20% by mass, MFR 2.5) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle size 35 nm, specific surface area 69 m 2 / g, DBP absorption 160 ml / 100 g) 16 parts by mass 1-Butyl-3-methylimidazolium chloride (imidazolium-based conductive liquid compound: [CH3NC3H3N(CH2)3CH3·Cl]) 8 parts by mass ※A composite conductor in which 4 parts by mass of 1-butyl-3-methylimidazolium chloride is adsorbed and supported on 8 parts by mass of acetylene black conductive powder is used.

[0031]

Table 1

[0032] [Example 5] The back layer (0.22 mm) of the antistatic tarpolin 1 of Example 1 was made into "ethylene-based copolymer resin intermediate layer (0.12 mm) [Formulation 1] / ethylene-based copolymer resin back conductive layer (0.1 mm) [Formulation 6]". Otherwise, it was the same as in Example 1, with a thickness of 0.67 mm and a mass of 649 g / m. 2The obtained tarpaulin 5 had excellent antistatic properties. [Formulation 6] Ethylene-based copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (Vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle diameter 35 nm, specific surface area 69 m 2 / g, DBP absorption capacity 160ml / 100g) 16 parts by weight Tetrabutylammonium hydrogen sulfate (quaternary ammonium conductive liquid compound) Matter: [(C4H9)4N·(HSO4)]) 8 parts by mass *8 parts by weight of acetylene black conductive powder and tetrabutylammonium sulfate solution Uses a composite conductor that adsorbs and supports 4 parts by mass of sodium chloride

[0033] [Example 6] The antistatic tarpaulin 2 of Example 2 had a thickness of 0.67 mm and a mass of 649 g / m, except that the back layer (0.22 mm) of the antistatic tarpaulin 2 of Example 2 was changed to "ethylene copolymer resin intermediate layer (0.12 mm) [Blend 1] / ethylene copolymer resin back conductive layer (0.1 mm) [Blend 7]". 2 Thus, Tarpaulin 6 was obtained. The obtained Tarpaulin 6 had excellent antistatic properties. [Formula 7] Ethylene-based copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (Vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle diameter 35 nm, specific surface area 69 m 2 / g, DBP absorption capacity 160ml / 100g) 10 parts by weight Oil furnace carbon black (conductive powder: particle diameter 40 nm, specific surface area Total area: 58m 2 / g, DBP absorption amount 168 ml / 100 g) 6 parts by mass Triethylsulfonium bis(trifluoromethanesulfonyl)imide (sulf onium-based conductive liquid compound: [(CH2CH3)3S·(CF3SO2)2 N]) 8 parts by mass ※ 5 parts by mass of acetylene black conductive powder and oil furnace-based carbon 3 parts by mass of black conductive powder, and 4 parts by mass of triethylsulfonium bis(trifluoromethanesulfonyl)imide adsorbed and supported to obtain a composite conductor is used

[0034] [Example 7] The back layer (0.22 mm) of the antistatic tarpolin 3 of Example 3 was made into "ethylene-based copolymer resin intermediate layer (0.12 mm) [formulation 1] / ethylene-based copolymer resin back conductive layer (0.1 mm) [formulation 8]", and otherwise the same as Example 3 to obtain a tarpolin 7 with a thickness of 0.67 mm and a mass of 649 g / m 2 The obtained tarpolin 7 had excellent antistatic properties because a part of the carbon fiber yarn (E) contained in the cross-section of the voids of the open-weave fabric 2 was in contact with the back conductive layer [Formulation 8] Ethylene-based copolymer resin composition Ethylene-vinyl acetate copolymer resin (EVA) (vinyl acetate content 20% by mass, MFR 2.0) 100 parts by mass Organic phosphate ester-based compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle size 35 nm, specific surface area 69 m 2 / g, DBP absorption amount 160 ml / 100 g) 16 parts by mass Butylpyridinium hexafluorophosphate (pyridinium-based conductive liquid compound: [CH3(CH2)3N·PF6]) 8 parts by mass ※ 8 parts by mass of acetylene black conductive powder and 4 parts by mass of butylpyridinium hexafluorophosphate adsorbed and supported to obtain a composite conductor is used

[0035] [Example 8] The back layer (0.22 mm) of the antistatic tarpolin 4 of Example 4 was made into "ethylene-based copolymer resin intermediate layer (0.12 mm) [Formulation 1] / ethylene-based copolymer resin back conductive layer (0.1 mm) [Formulation 9]", and the same as in Example 4 except for this, a tarpolin 8 with a thickness of 0.67 mm and a mass of 649 g / m 2 was obtained. Since the obtained tarpolin 8 had a structure in which a part of the carbon fiber yarn (E) contained in the cross-section of the voids of the open-weave fabric 3 was in contact with the back conductive layer, it had excellent antistatic properties. [Formulation 9] Ethylene-based copolymer resin composition Ethylene-methyl methacrylate copolymer resin (EMMA) (methyl methacrylate content 20% by mass, MFR 2.5) 100 parts by mass Organic phosphate ester compound (liquid lubricant) 1 part by mass Acetylene black (conductive powder: particle size 35 nm, specific surface area 69 m 2 / g, DBP absorption 160 ml / 100 g) 16 parts by mass 1-Butyl-3-methylimidazolium chloride (imidazolium-based conductive liquid compound: [CH3NC3H3N(CH2)3CH3·Cl]) 8 parts by mass ※ Use a composite conductor in which 4 parts by mass of 1-butyl-3-methylimidazolium chloride is adsorbed and supported on 8 parts by mass of acetylene black conductive powder

[0036]

Table 2

[0037] [Comparative Example 1] 8 parts by mass of the acetylene black (conductive powder: particle size 35 nm, specific surface area 69 m 2 / g, DBP absorption 160 ml / 100 g) of [Formulation 2] in Example 1 was replaced with oil furnace-based carbon black (conductive powder: particle size 40 nm, specific surface area 58 m 2 ​Except that it was replaced with [Formulation 10] in which the DBP absorption amount was 168 ml / 100 g and the amount of the 8 mass parts was used, the same procedure as in Example 1 was carried out to obtain a tarpolin 9 with a thickness of 0.67 mm and a mass of 649 g / m 2 The obtained tarpolin 9 was excellent in antistatic properties. However, spark ignition occurred during high-frequency welding when preparing the heat-resistant creep test piece for the joint part, and it had a specification accompanied by the risk of an electrical accident.

[0038] [Comparative Example 2] Except that it was changed to [Formulation 11] in which 4 mass parts of tetrabutylammonium hydrogensulfate in [Formulation 2] of Example 1 was omitted, the same procedure as in Example 1 was carried out to obtain a tarpolin 10 with a thickness of 0.67 mm and a mass of 649 g / m 2 The obtained tarpolin 10 was inferior in antistatic properties to tarpolin 1. To obtain antistatic properties equivalent to those of tarpolin 1, it was uneconomical to increase the amount of 8 mass parts of acetylene black in [Formulation 11] to 12 mass parts.

[0039] [Comparative Example 3] Except that it was changed to [Formulation 12] in which 8 mass parts of acetylene black in [Formulation 2] of Example 1 was omitted, the same procedure as in Example 1 was carried out to obtain a tarpolin 11 with a thickness of 0.67 mm and a mass of 649 g / m 2 The obtained tarpolin 11 was inferior in antistatic properties to tarpolin 1. Not only could antistatic properties equivalent to those of tarpolin 1 not be obtained even when the amount of 4 mass parts of tetrabutylammonium hydrogensulfate in [Formulation 12] was increased to 12 mass parts, but also a problem of sticky contamination occurred where tetrabutylammonium hydrogensulfate bled out on the surface of tarpolin 11.

[0040] [Comparative Example 4] In [Formulation 2] of Example 1, the step of adsorbing and supporting 4 parts by mass of tetrabutylammonium hydrogen sulfate on 8 parts by mass of acetylene black conductive powder was omitted, and 8 parts by mass of acetylene black conductive powder and 4 parts by mass of tetrabutylammonium hydrogen sulfate were directly compounded with 100 parts by mass of ethylene-vinyl acetate copolymer resin. An ethylene-based copolymer resin back conductive layer (thickness 0.67 mm, mass 649 g / m, the same as in Example 1 except that a black film with a thickness of 0.22 mm was calendered and molded) was obtained from the compound. 2 The obtained terpolymer 12 had a part of the organic phosphate ester compound of the liquid lubricant adhering to the surface of the acetylene black conductive powder, and the antistatic property was inferior to that of terpolymer 1 due to the adverse effect of inhibiting the conductivity of the acetylene black structure. To obtain the same antistatic property as terpolymer 1, there was the uneconomy of increasing the amount of 8 parts by mass of acetylene black in [Formulation 2] to 10 parts by mass.

[0041]

Table 3

Industrial Applicability

[0042] According to the present invention, it is possible to provide a terpolymer having antistatic property and further explosion-proof property (JIS C61340 4-4), and a method for manufacturing the same. Therefore, by using this terpolymer, it is possible to provide a flexible container bag having antistatic property and further explosion-proof property (JIS C61340 4-4) which is safely high-frequency welded.

Explanation of Symbols

[0043] 1: Antistatic terpolymer 2: Open-mesh fabric 2-1: Warp 2-1-1: Multifilament yarn (M) 2-1-2: Conductive fiber yarn (E) 2-2: Weft 2-2-1: Multifilament yarn (M) 2-2-2: Conductive fiber yarn (E) 3-1: Ethylene-based copolymer resin surface layer 3-2: Ethylene-based copolymer resin back conductive layer 3-3: Ethylene-based copolymer resin intermediate layer

Claims

1. A tarpolin constituting a cross-section of "ethylene-based copolymer resin surface layer / open-mesh fabric / ethylene-based copolymer resin back conductive layer", or a tarpolin constituting a cross-section of "ethylene-based copolymer resin surface layer / open-mesh fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", wherein the ethylene-based copolymer resin back conductive layer contains a composite conductor, and this composite conductor consists of a conductive powder and a conductive liquid compound, and a part or all of this conductive liquid compound is adsorbed and supported by the conductive powder, the conductive powder is acetylene black alone or a combination of acetylene black and oil furnace carbon black, and the conductive liquid compound is an ion pair of a cation and an anion, characterized in that it is an antistatic tarpolin.

2. The cation is one selected from the group consisting of imidazolium-based, imidazolinium-based, pyridinium-based, pyrazolium-based, pyrrolidinium-based, piperidinium-based, quaternary ammonium-based, phosphonium-based, sulfonium-based, and the anion has the chemical formula BF ４ - 、PF ６ - 、TaF ６ - 、NbF ６ - 、SiF ６ - 、AlF ４ - 、AlCl ４ - 、NO ２ - 、NO ３ - 、F - 、Cl - 、Br - 、I - 、CN - 、AsF ６ - 、SbF ６ - 、NbF ６ - 、TaF ６ - 、CF ３ SO ２ - , CF ３ SO ４ - , (CF ３ SO ２ ) ２ N - , p-CH ３ PhSO ３ - , CH ３ CO ２ - , HSO ４ - , HSO ３ - , CH ３ SO ３ - , CH ３ SO ４ - , CF ３ SO ３ - , (CF ３ SO ２ ) ３ C - , C ３ F ７ CO ２ - , C ４ F ９ SO ３ - , (C ２ F ５ SO ２ ) ２ N - , (CF ３ SO ２ )(CF ３ CO)N - , (CN) ２ N - 、The antistatic tarpolin according to claim 1, which is one selected from the following.

3. The surface layer of the ethylene-based copolymer resin, the intermediate layer of the ethylene-based copolymer resin, and the back conductive layer of the ethylene-based copolymer resin are mainly composed of the ethylene-based copolymer resin. This ethylene-based copolymer resin is one or more selected from ethylene-vinyl acetate copolymer resin, ethylene-acrylic acid copolymer resin, ethylene-acrylic acid ester copolymer resin, ethylene-methacrylic acid copolymer resin, ethylene-methacrylic acid ester copolymer resin, and the content of ethylene units is 65 to 85% by mass. The antistatic tarpolin according to claim 1 or 2.

4. The antistatic tarpolin according to any one of claims 1 to 3, wherein a part of the open-weave fabric contains conductive fiber yarns.

5. A method for manufacturing a tarpolin that forms a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin back conductive layer" or a tarpolin that forms a cross-section of "ethylene-based copolymer resin surface layer / open-weave fabric / ethylene-based copolymer resin intermediate layer / ethylene-based copolymer resin back conductive layer", The back conductive layer of the ethylene-based copolymer resin contains a composite conductor composed of a conductive powder and a conductive liquid compound. During the production of the back conductive layer of the ethylene-based copolymer resin or at the preparation stage of the production, a step of adsorbing and supporting part or all of the conductive liquid compound on the conductive powder to process it into the composite conductor, A step of molding an ethylene-based copolymer resin layer film containing this composite conductor and laminating it on the open-weave fabric or the intermediate layer of the ethylene-based copolymer resin is included, The manufacturing method of the antistatic tarpolin, wherein the conductive powder is acetylene black alone or a combination of acetylene black and oil furnace carbon black, and the conductive liquid compound is an ion pair of a cation and an anion.

6. The cation is one selected from imidazolium-based, imidazolinium-based, pyridinium-based, pyrazolium-based, pyrrolidinium-based, piperidinium-based, quaternary ammonium-based, phosphonium-based, sulfonium-based, and the anion has the chemical formula BF ４ - , PF ６ - , TaF ６ - , NbF ６ - , SiF ６ - , AlF ４ - , AlCl ４ - , NO ２ - , NO ３ - , F - , Cl - , Br - , I - , CN - , AsF ６ - , SbF ６ - , NbF ６ - , TaF ６ - , CF ３ SO ２ - , CF ３ SO ４ - , (CF ３ SO ２ ) ２ N - , p-CH ３ PhSO ３ - , CH ３ CO ２ - , HSO ４ - , HSO ３ - , CH ３ SO ３ - , CH ３ SO ４ - , CF ３ SO ３ - , (CF ３ SO ２ ) ３ C - , C ３ F ７ CO ２ - , C ４ F ９ SO ３ - , (C ２ F ５ SO ２ ) ２ N - , (CF ３ SO ２ )(CF ３ CO)N - , (CN) ２ N - The method for manufacturing an antistatic tarpaulin according to claim 5, which is one selected from the group consisting of

7. The method for manufacturing an antistatic tarpaulin according to claim 5 or 6, wherein a part of the open-weave fabric contains conductive fiber yarns.

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