Plastic film

Abstract

To provide a sleeve which is a laminate that coats a resin pipe such as a water pipe embedded in the ground and has high transparency, is not damaged even by strongly contacting a sharp stone such as gravel, and is prevented from contacting the water supply pipe even when soil is contaminated with kerosene and a halogen compound.SOLUTION: A sleeve composed of a laminate using a plastic film has a sealant layer inside the sleeve of the laminate and a piercing resistant layer outside the sleeve, and has a barrier layer of kerosene resistant and / or halogen-based gas in a sleeve intermediate layer.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] To provide a highly transparent laminated sleeve for covering resin pipes such as water pipes buried underground, which is not broken even when it comes into strong contact with sharp stones such as gravel, and which does not come into contact with water pipes even when the soil is contaminated with kerosene or halogen compounds. [Background technology]

[0002] Generally, water pipes are widely used, being made of cast iron pipes or standardized plastic pipes such as polyethylene pipes and polyvinyl chloride pipes, due to their light weight, flexibility, and earthquake resistance, and are often buried underground. However, cast iron pipes are susceptible to rust caused by moisture and oxygen, which can lead to further corrosion, while plastic pipes are susceptible to the penetration of underground solvents and other contaminants into the pipe interior.

[0003] In order to address these issues, Patent Document 1 discloses a sleeve that is made up of, from the inside of the sleeve of a laminate, a sealant layer, a stretched polyamide film layer, a gas barrier film layer having an inorganic compound on its surface, and a stretched polyethylene terephthalate film layer, in that order. In particular, by placing a stretched polyamide film layer adjacent to the sealant layer and a stretched polyethylene terephthalate film layer as the outermost layer of the sleeve, tearing or holes in the seal edge are less likely to occur during installation and burial work, and deterioration over time, including of the sleeve itself, is also less likely.

[0004] Furthermore, Patent Document 2 discloses a laminated film made of a resin layer and a metal layer that covers water pipes buried underground at the points where they intersect above and below, preventing tap water from smelling like petroleum due to kerosene seeping out of corroded kerosene pipes. In particular, by forming a metal layer as part of the laminate, it is possible to achieve kerosene resistance. [Prior art documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-065912 [Patent Document 2] Patent No. 4230060 Publication Summary of the Invention [Problem to be solved by the invention]

[0006] Sleeves used for underground pipes are generally made of resin film, but since they may be exposed to kerosene or gasoline depending on the underground environment and burial work, they require puncture resistance and resistance to kerosene and gasoline.Furthermore, they also require barrier properties against soil contamination by halogenated organic compounds. To solve these problems, a film containing a metal layer may be considered, but this impairs transparency, making it impossible to clearly see the state of the piping from outside the sleeve. The present invention aims to solve these problems by providing a sleeve that is highly transparent, puncture-resistant, and kerosene- and gasoline-resistant, and also provides a novel sleeve that has barrier properties against soil contamination by halogenated organic compounds. [Means for solving the problem]

[0007] The present invention relates to a sleeve made of a laminate using a plastic film, which has a sealant layer on the inside of the sleeve of the laminate, a puncture-resistant layer on the outside of the sleeve, and a kerosene-resistant and / or halogen-based gas barrier layer in the middle layer of the sleeve.

[0008] The present invention relates to the above-mentioned sleeve, wherein the puncture-resistant layer is made of a polyamide film or a polyester film.

[0009] The present invention relates to the above-mentioned sleeve, wherein the kerosene and / or halogen gas resistant barrier layer is provided with a vapor-deposited layer of an inorganic compound.

[0010] The present invention relates to the above sleeve, characterized in that a kerosene-resistant adhesive layer is provided between the sealant layer on the inner side of the sleeve and the intermediate layer of the laminate. [Effects of the Invention]

[0011] The sleeve of the present invention has puncture resistance against sharp stones such as gravel, resistance to kerosene and gasoline caused by underground contamination, and barrier properties against halogenated organic compounds, even when exposed to buried construction or underground environments, and is transparent enough to allow the surface condition of the covered pipe to be clearly seen. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view schematically showing an example of a laminate sleeve of the present invention. [Figure 2] 1 is a cross-sectional view schematically showing an example of a sleeve provided with a kerosene-resistant adhesive layer of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] <Sleep> The laminate (A) constituting the sleeve of the present invention is a sleeve made of a laminate using a plastic film. In the example shown in Figure 1, the laminate (A) is composed of, from the outside of the sleeve, (1) an outer layer, which is a puncture-resistant film layer, (2) intermediate layers, (2-a) a barrier layer against halogen-based organic compounds, (2-b) a kerosene- and gasoline-resistant barrier layer, and (3) a sealant layer. By adopting this configuration, each of the problems can be solved simultaneously.

[0014] 2, the laminate (A) constituting the sleeve of the present invention has a (2-c) kerosene-resistant adhesive layer between the (2-b) kerosene- and gasoline-resistant barrier layer and the (3) sealant layer, which not only enhances the kerosene- and gasoline-resistant barrier effect but also improves the physical strength of the film. Specifically, this improves the tear strength, tensile strength, and peel strength between the sealant layer and the intermediate layer.

[0015] In particular, since the sleeve of the present invention uses a highly transparent film as a layer structure, the transparency of the sleeve itself is high.

[0016] The sleeve is formed by forming a laminate by a known method such as dry lamination or wet lamination, etc. In this embodiment, the dry lamination method is used.

[0017] <Outer layer> The puncture-resistant film layer (1), which is the outer layer of the present invention, can be suitably made of a stretched polyamide film or a stretched polypropylene film. It can also be made up of two film layers. The two layers can be made of the same type of plastic film or different plastic films, but it is more preferable to use different plastic films. This is because using different plastic films improves puncture resistance compared to using the same type of plastic film. Furthermore, this outer layer can be printed with ink, and if there are multiple outer layers, the ink can be applied to any of the layers.

[0018] That is, by providing a polyamide film, polypropylene film or polyester film that has excellent puncture resistance, it is possible to make the sleeve more resistant to external forces such as punctures.

[0019] Specifically, it is preferable to use a stretched polyamide film as the polyamide film, a stretched polypropylene film as the polypropylene film, or a stretched polyethylene terephthalate film as the polyester film. These films may also be laminated, for example, a laminate of a stretched polyamide film and a stretched polypropylene film, a laminate of a stretched polyamide film and a stretched polyethylene terephthalate film, or a laminate of a stretched polypropylene film and a stretched polyethylene terephthalate film. Furthermore, a laminate of a stretched polyamide film, a stretched polypropylene film, and a stretched polyethylene terephthalate film may also be used. However, from the viewpoint of handleability due to the increase in film thickness as well as the transparency of the entire sleeve, it is preferable to use the film as a single film.

[0020] <Middle class> The intermediate layer is composed of (2-a) a barrier layer against halogenated organic compounds, and (2-b) a barrier layer resistant to kerosene and gasoline. Furthermore, to increase the adhesive strength between the film's sealant layer and the intermediate layer, (2-c) a kerosene-resistant adhesive layer can be included. When the sleeve is buried underground, a gas barrier layer (2) is provided in the laminate (A) that constitutes the sleeve to protect the pipe from the effects of halogenated organic compounds and provide better internal protection. The sealant layer on the inside of the gas barrier layer is also protected from the effects of halogenated organic compounds, preventing the sealant layer from deteriorating and preventing peeling even after long periods of burial. In particular, by providing a barrier layer with a specific function as the middle layer, the sleeve can be more effectively used when buried underground.

[0021] (2-a) Barrier layer against halogenated organic compounds As a barrier layer against halogen-based organic compounds, a gas barrier film formed by providing a vapor-deposited layer of an inorganic compound on a plastic film can be used. In particular, in contaminated underground, there are many cases where contact with halogenated organic compounds is a concern, and barrier properties against this are also highly required.

[0022] Halogen-based organic compounds include chloromethane, dichloromethane, trichloromethane, tetrachloromethane, chloroethylene, dichloroethylene, trichloroethylene, tetrachloroethylene, chlorobenzene, dichlorobenzene, trichlorobenzene, etc. These are recognized as toxic and carcinogenic substances and should not be contained in water supplies.

[0023] Although it is possible to use a metal foil such as aluminum as the barrier layer, it is susceptible to the effects of moisture, etc., although it has gas barrier properties. Therefore, a gas barrier film provided with a vapor-deposited layer of an inorganic compound is preferably used.

[0024] In the case of a gas barrier film provided with a vapor-deposited layer of an inorganic compound, the plastic film used as the substrate is a film made of a polymer resin composition, such as polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (nylon-6, nylon-66, etc.), polyimide, etc., and the film can be selected appropriately depending on the application.

[0025] In particular, polypropylene, polyamide, and polyethylene terephthalate (PET) are preferable plastic film substrates in terms of film strength and cost.

[0026] Barrier properties can be imparted by forming a vapor-deposited layer and a coating layer of an inorganic compound on a substrate. After providing an anchor coat on a plastic film, a vapor-deposited layer and a coating layer are formed in this order.

[0027] For example, urethane acrylate can be used for the anchor coat layer of the barrier film. The anchor coat layer can be formed by using a coating method that applies a printing technique such as gravure coating with a paint in which a resin is dissolved in a solvent, or by using a commonly known coating method to form a coating film.

[0028] The method for forming a vapor deposition layer is to coat inorganic compounds such as SiO2 or Al2O3 onto a plastic film with an anchor coat layer using vacuum deposition, and an inorganic compound layer can be formed using vacuum deposition. The thickness of the vapor deposition layer should be 15nm to 30nm. Aluminum vapor deposition can also be used in the same way.

[0029] The coating layer can be formed by applying a coating agent, the main component of which is an aqueous solution or a water / alcohol mixed aqueous solution containing a water-soluble polymer and at least one of (a) one or more alkoxides or their hydrolysates, or both, or (b) tin chloride, onto a film, and then heating and drying the coating agent to form an inorganic compound layer by the coating method.

[0030] In this case, by adding a silane monomer to the coating agent, it is possible to improve adhesion with the anchor coat layer.

[0031] Although the inorganic compound layer has barrier properties even when it is only a coating film formed by vacuum deposition, a barrier layer can also be formed by overlaying a coating layer, which is an inorganic compound layer formed by a coating method, on a vapor deposition layer, which is an inorganic compound layer formed by vacuum deposition.

[0032] By combining these two layers, a reaction layer between the inorganic compound layer formed by vacuum deposition and the inorganic compound layer formed by coating is generated at the interface between the two layers, or the inorganic compound layer formed by coating fills and reinforces defects or micropores such as pinholes, cracks, and grain boundaries that occur in the inorganic compound layer formed by vacuum deposition, thereby forming a dense structure.

[0033] Therefore, the film can achieve higher barrier properties, moisture resistance, and water resistance as a barrier film, and has flexibility that allows it to withstand deformation due to external forces, making it suitable as a material for forming a sleeve.

[0034] Furthermore, when SiO2 is used as the barrier layer, for example, the coating is transparent, so that the inside can be seen from the outside of the sleeve.

[0035] (2-b) Kerosene and gasoline resistant barrier layer For the kerosene- and gasoline-resistant barrier layer, silica-deposited polypropylene film, alumina-deposited polypropylene film, silica-deposited polyethylene terephthalate film, alumina-deposited polyethylene terephthalate film, nylon-based elastomer film (MXD6), ethylene-vinyl alcohol copolymer film (EVOH), polyvinylidene chloride copolymer resin film (PVDC), polyacrylonitrile film (PAN), etc. Aluminum-deposited or laminated aluminum film can also be used, but its use is not recommended from the standpoint of transparency and environmental impact. These resin films are known to have water vapor and oxygen barrier properties, but can also be used to provide resistance to kerosene and gasoline. The present invention can also exhibit high water vapor barrier properties. Further specific products that can be used include IB-FILM (registered trademark) manufactured by DNP, GL FILM (registered trademark) and GL BARRIER (registered trademark) manufactured by Toppan Printing Co., Ltd., Speren (registered trademark) manufactured by Ube Films, and Max Barrier (registered trademark) and V Barrier (registered trademark) manufactured by RM Tocello Co., Ltd.

[0036] The order of lamination is (2-a) a barrier layer against halogenated organic compounds, and (2-b) a kerosene- and gasoline-resistant barrier layer, with the layer adjacent to the outer layer, but the order of (2-a) and (2-b) may be reversed.

[0037] (2-c) Kerosene-resistant adhesive layer By providing a kerosene-resistant adhesive layer between the kerosene- and gasoline-resistant barrier layer and (3) the sealant layer, it is possible to reduce the weakening of the adhesive strength between the sealant layer and the kerosene- and gasoline-resistant barrier layer caused by kerosene and gasoline. As a result, it is possible not only to block kerosene and gasoline that have permeated the sealant layer from entering the intermediate layer, but also to prevent kerosene and other contaminants from leaking through the gap between the sealant layer and the kerosene- and gasoline-resistant barrier. Specifically, the kerosene-resistant adhesive layer is made of a modified polyolefin, such as modified polyethylene or modified polypropylene, which has adhesive properties imparted by introducing functional groups into the polyolefin. This is preferable because it has the characteristic of strongly adhering to barrier resin films, such as the silica-deposited polyethylene terephthalate film and EVOH film, as well as substrates such as metal, glass, and ceramics.

[0038] In principle, it is preferable to place the (2-c) kerosene-resistant adhesive layer between the kerosene-resistant and gasoline-resistant barrier layer and the (3) sealant layer, but in addition, it can also be placed between the two intermediate layers, the (2-a) barrier layer to halogen-based organic compounds and the (2-b) kerosene-resistant and gasoline-resistant barrier layer.

[0039] (3) Sealant layer The sealant layer is made by stacking two plastic films with the same layer structure so that the sealant layers face each other, and then heat-sealing them by applying heat and pressure to bond them together, making it possible to form a tubular sleeve around the outside of piping or wiring.

[0040] As the material for the sealant layer (3), linear low-density polyethylene resin (LLDPE) is preferably used from the viewpoint of long-term sealing properties as the sealant layer for the sleeve of the buried pipe, but other polyolefin resins etc. can also be generally used.

[0041] Specifically, ethylene-based resins such as low-density polyethylene resin (LDPE), medium-density polyethylene resin (MDPE), ethylene-vinyl acetate copolymer (EVA), ethylene-α-olefin copolymer, and ethylene-methacrylic acid resin copolymer can be used.

[0042] Also usable are blend resins of polyethylene and polybutene, and polypropylene-based resins such as homopolypropylene resin (PP), propylene-ethylene random copolymer, propylene-ethylene block copolymer, and propylene-α-olefin copolymer.

[0043] The sealant layer (3) can be formed by forming a film from a molten resin using an extruder or the like and forming a layer on the laminate (A). Alternatively, the sealant layer (3) can be formed on the surface of the laminate (A) by laminating a material that has already been formed into a film.

[0044] Inorganic oxides, such as oxides of inorganic elements other than alkali metals and alkaline earth metals, can be used in each layer to prevent penetration of organic halogens, kerosene, etc. These have excellent adsorption properties for organic halogen compounds. Specific examples of the inorganic oxide include Al2O3, SiO2, P2O5, hydrophilic zeolite, etc. Among these, Al2O3 and hydrophilic zeolite are preferred. However, since adding it to the sealant layer reduces the seal strength, it is preferable to avoid adding it in excess to the sealant layer.

[0045] <Haze measurement> The transparency of the sleeve is measured by haze (%). The haze was measured in accordance with JIS K 7136 (2000) using an NDH-5000 (manufactured by Nippon Denshoku Industries Co., Ltd.). The lower the value, the more transparent the film. A value of 10 or less is acceptable, preferably 8 or less, and particularly preferably 5 or less.

[0046] <Kerosene smell> The odor and taste of kerosene are confirmed using the odor test method specified in the leaching test of JIS K 6762.

[0047] <Detection of organic halogens> One side of the sleeve was contacted with an n-hexane solution of trichloroethylene, and the other side was contacted with an n-hexane solution, and the eluted trichloroethylene was detected using a gas chromatograph-electron capture detector (GC-ECD) analyzer.

[0048] <Penetration strength evaluation> The puncture strength is evaluated using the test method specified in JIS Z 2019.

[0049] As shown in Figures 1 and 2, the laminated sleeve made by the method of the present invention has excellent transparency, impact resistance, puncture resistance, kerosene and gasoline resistance, and barrier resistance to halogen-based organic compounds. The specific layer structure is shown below. [Example]

[0050] The outermost layer of the sleeve laminate was oriented polyethylene terephthalate, the inner layer was oriented nylon, the middle layer was silica-deposited polyethylene terephthalate, and the sealant layer was LLDPE. Each film thickness was 10 μm. The laminate had good transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties to halogen-based organic compounds. [Example]

[0051] The outermost layer of the sleeve laminate was unstretched polyethylene terephthalate, the inner layer was a stretched nylon layer, the middle layer was silica-deposited polyethylene terephthalate, and the sealant layer was LLDPE. Each film thickness was 10 μm. The transparency, impact resistance, and puncture resistance of the laminate were slightly inferior, but the resistance to kerosene and gasoline, and the barrier properties to halogen-based organic compounds were good. [Example]

[0052] The outermost layer of the sleeve laminate was oriented polyethylene terephthalate, the inner layer was oriented nylon, the middle layer was alumina-deposited polyethylene terephthalate, and the sealant layer was LLDPE. Each film thickness was 10 μm. The laminate had good transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties to halogen-based organic compounds. [Example]

[0053] The outermost layer of the sleeve laminate was a stretched polypropylene film, the inner layer was a stretched nylon layer, the middle layer was silica-deposited polyethylene terephthalate, and the sealant layer was LLDPE. Each film was 10 μm thick. The laminate had good transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties to halogen-based organic compounds. [Example]

[0054] The outermost layer of the sleeve laminate was a stretched polypropylene film, the inner layer was a stretched nylon layer, the middle layer was alumina-deposited polyethylene terephthalate, and the sealant layer was LLDPE. Each film was 10 μm thick. The laminate had good transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties to halogen-based organic compounds. [Example]

[0055] The outermost layer of the sleeve laminate was a stretched polyethylene terephthalate film, the inner layer was a stretched nylon layer, the middle layer was silica-deposited polyethylene terephthalate, and the adhesive layer was LLDPE as a sealant layer. Each film thickness was 10 μm. The laminate had good transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties to halogen-based organic compounds. [Example]

[0056] The outermost layer of the sleeve laminate was a stretched polyethylene terephthalate film, the inner layer was a stretched nylon layer, the middle layer was silica-deposited polyethylene terephthalate, the adhesive layer was modified polyethylene, and the sealant layer was LLDPE. Each film was 10 μm thick. The laminate had excellent transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties against halogenated organic compounds. [Example]

[0057] The outermost layer of the sleeve laminate was a stretched polyethylene terephthalate film, the inner layer was a stretched nylon layer, the middle layer was alumina-deposited polyethylene terephthalate, the adhesive layer was modified polypropylene, and the sealant layer was LLDPE. Each film was 10 μm thick. The laminate had excellent transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties against halogenated organic compounds. [Example]

[0058] The outermost layer of the sleeve laminate was a stretched polyethylene terephthalate film, the inner layer was a stretched nylon layer, the middle layer was an EVOH film, the adhesive layer was modified polypropylene, and the sealant layer was LLDPE. Each film was 10 μm thick. The laminate had excellent transparency, impact resistance, puncture resistance, resistance to kerosene and gasoline, and barrier properties against halogenated organic compounds.

[0059] Comparative Example 1: The outermost layer of the sleeve laminate was LLDPE, the inner layer was a non-oriented polyethylene terephthalate layer, and the inner layer was an oriented nylon layer. There was no intermediate layer, and the sealant layer was LLDPE. Each film thickness was 10 μm. The laminate had good transparency, impact resistance, and puncture resistance, but poor resistance to kerosene and gasoline, and barrier properties against halogen-based organic compounds.

[0060] Comparative Example 2: The outermost layer of the sleeve laminate was LLDPE, the inner layer was a non-oriented polyethylene terephthalate layer, and furthermore, an oriented nylon layer, the middle layer was an EVOH layer, and the sealant layer was LLDPE. Each film thickness was 10 μm. The laminate had good transparency, impact resistance, puncture resistance, and resistance to kerosene and gasoline, but its barrier properties against halogen-based organic compounds were poor. [Industrial Applicability]

[0061] The plastic film of the present invention can be suitably used as an excellent film for packaging and transporting fisheries products (especially sharp seafood such as crabs and oysters), infrastructure components to be buried underground, covering materials for agricultural greenhouses, and construction materials. [Explanation of symbols]

[0062] A···Laminate (Sleeve) 1. Outer layer (puncture-resistant layer) 2. Middle class 2-a Barrier layer for halogenated organic compounds 2-b Kerosene and gasoline resistant barrier layer 2-c Kerosene-resistant adhesive layer 3. Sealant layer

Claims

1. A sleeve made of a laminate using a plastic film, which has a sealant layer on the inside of the sleeve of the laminate, a puncture-resistant layer on the outside of the sleeve, and a kerosene- and / or halogen-based gas barrier layer in the middle layer of the sleeve.

2. 2. The sleeve according to claim 1, wherein the puncture-resistant layer is a polyamide film or a polyester film.

3. 3. The sleeve according to claim 1, wherein the kerosene and / or halogen gas resistant barrier layer is provided with a vapor-deposited layer of an inorganic compound.

4. 4. The sleeve according to claim 1, wherein a kerosene-resistant adhesive layer is provided between the sealant layer on the inner side of the sleeve and the intermediate layer of the laminate.

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