Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B27/00—Layered products comprising a layer of synthetic resin
  • B32B27/40—Layered products comprising a layer of synthetic resin comprising polyurethanes
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
  • B32B7/04—Interconnection of layers
  • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
  • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
  • B65D65/00—Wrappers or flexible covers; Packaging materials of special type or form
  • B65D65/38—Packaging materials of special type or form
  • B65D65/40—Applications of laminates for particular packaging purposes
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
  • C09J175/00—Adhesives based on polyureas or polyurethanes; Adhesives based on derivatives of such polymers
  • C09J175/04—Polyurethanes

Definitions

• the present disclosure relates to a laminate, a packaging bag including the laminate, and a method for manufacturing the laminate.
• packaging bags made of plastic film are becoming popular to replace bottles and cans.
• flexible bags are made by pasting two or more films with adhesive to improve their performance, such as strength, water resistance, moisture permeability, gas barrier properties against oxygen and other gases, and heat resistance. It consists of a laminated body.
• Patent Document 1 proposes a solvent-free adhesive composition that can form a boilable laminate. has been done.
• the present invention has been made to solve this problem, and provides a laminate having excellent strength and physical properties, in which films, at least one of which is a gas barrier film, are bonded together using a solvent-free adhesive.
• the purpose is to Another object of the present invention is to provide a packaging bag including the laminate, and a method for manufacturing the laminate.
• the present invention relates to, for example, the following [1] to [12].
• a laminate comprising a first film, an adhesive layer, and a second film in this order, The first film and the second film are laminated via the adhesive layer, At least one of the first film and the second film has a gas barrier layer,
• the adhesive layer is a cured product of a solvent-free two-component curing polyurethane adhesive
• a laminate wherein the area ratio of air bubbles based on the area of the adhesive layer is 4% or less when the adhesive layer is observed from the lamination direction of the laminate.
• the laminate according to [1] wherein the number of bubbles is 10 to 90/cm 2 when the adhesive layer is observed from the lamination direction of the laminate.
• the number of bubbles having an area of 0.5 mm 2 or more when observing the adhesive layer from the lamination direction of the laminate is 10 pieces/cm 2 or less, [1] or [2] ]
• [4] The laminate according to any one of [1] to [3], wherein the bubbles have an average diameter of 400 ⁇ m or less when the adhesive layer is observed from the lamination direction of the laminate.
• [5] In the cross section of the adhesive layer, the ratio of the average diameter of the bubbles in the lamination direction of the laminate to the thickness of the adhesive layer (average diameter of bubbles/thickness of the adhesive layer) is 1. 5 or less, the laminate according to any one of [1] to [4].
• a method for producing a laminate comprising a first film, an adhesive layer, and a second film in this order, At least one of the first film and the second film has a gas barrier layer, a laminating step of laminating the first film and the second film together via a solvent-free two-component curing polyurethane adhesive to obtain a laminate; a curing step of curing the laminate at 25 to 80°C to obtain the laminate; Equipped with A method for manufacturing a laminate, wherein the area ratio of air bubbles based on the area of the adhesive layer is 4% or less when the adhesive layer is observed from the lamination direction of the laminate.
• the manufacturing method according to [10] wherein the curing step is carried out at 25 to 50°C for 1 hour or more.
• a laminate having excellent strength and physical properties in which films, at least one of which is a gas barrier film, are bonded together using a solvent-free adhesive. Further, according to the present invention, it is possible to provide a packaging bag including the laminate and a method for manufacturing the laminate. Films in which at least one of them is a gas barrier film means a gas barrier film and a non-gas barrier film, or a gas barrier film.
• FIG. 1 is a schematic cross-sectional view showing one embodiment of the laminate of the present invention.
• FIG. 2 is an enlarged view of the schematic cross-sectional view of FIG. 1.
• FIG. 3 is a schematic cross-sectional view showing another embodiment of the laminate of the present invention.
• a numerical range indicated using "-" indicates a range that includes the numerical values written before and after "-" as the minimum and maximum values, respectively. Furthermore, unless specifically specified, the units of numerical values written before and after " ⁇ " are the same.
• the upper limit or lower limit of the numerical range of one step may be replaced with the upper limit or lower limit of the numerical range of another step. Further, in the numerical ranges described in this specification, the upper limit or lower limit of the numerical range may be replaced with the value shown in the Examples.
• the upper limit values and lower limit values described individually can be combined arbitrarily.
• the laminate forming the packaging bag is obtained by bonding together a plurality of films having functions such as mechanical strength, barrier properties, light resistance, and unsealability required for the packaging bag via an adhesive layer.
• the innermost layer of the laminate may include a film having sealant properties for sealing the bag.
• the laminate may include a film provided with a barrier layer for the purpose of improving oxygen, gas, and water vapor barrier properties and protecting the contents.
• Embodiments 1 and 2 shown below a laminate obtained by bonding two or three films each having functionality through an adhesive layer will be described. The material of each film and the type of gas barrier layer are appropriately adjusted so that the adhesive layer can be observed.
• a laminate in which films, at least one of which is a gas barrier film, are bonded together using a solvent-free adhesive, and which have excellent strength and physical properties include: A laminate in which a PET film provided with an inorganic vapor-deposited layer, a polyamide film on the inorganic vapor-deposited layer side of the PET film, and a polypropylene sealant film are laminated in this order, PET film and polyamide film are laminated with an adhesive layer, and polyamide film and polypropylene sealant film are laminated with another adhesive layer, The adhesive layer and the other adhesive layer are cured products of a solvent-free two-component curing polyurethane adhesive, Examples include a laminate in which the area ratio of air bubbles based on the area of the adhesive layer is 4% or less when the adhesive layer is observed from the lamination direction of the laminate.
• FIG. 1 is a schematic cross-sectional view showing one embodiment of the laminate of the present invention.
• the laminate 10 in FIG. 1 includes a first film 1, an adhesive layer S1, and a second film 2 in this order. They are laminated with the agent layer S1 interposed therebetween.
• the thickness of the laminate 10 is, for example, 10 to 300 ⁇ m, may be 30 to 160 ⁇ m, or may be 30 to 100 ⁇ m.
• the first film 1 may be a base film of the laminate 10, and includes, for example, a resin film such as a stretched resin film.
• the stretched resin film may be a uniaxially stretched resin film or a biaxially stretched resin film.
• resin films include polyesters such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate, polyamides such as nylon, and polyolefins such as polypropylene, polyethylene, polymethylpentene, ethylene-propylene copolymers, and propylene-butene copolymers.
• a stretched film of polystyrene, polyimide, polyvinyl alcohol, polyvinyl chloride, ethylene-vinyl alcohol copolymer, etc., a composite film of two or more of these films laminated, etc. can be used.
• the first film 1 may be formed by laminating a stretched resin film and an unstretched resin film.
• aluminum foil can also be used as the first film.
• the first film may be provided with a printed layer.
• the first film is not particularly limited, but may have transparency so that a pattern formed by the printed layer can be displayed.
• the printing layer is an ink layer formed of one or more inks.
• the ink for example, general gravure ink, flexographic ink, offset ink, and digital printing ink can be used.
• examples of the binder resin include a mixture of a urethane resin and a vinyl chloride-vinyl acetate copolymer resin.
• the color ink may contain various additives other than the pigment and the binder resin, and a solvent (for example, a volatile organic solvent).
• a solvent for example, a volatile organic solvent
• the color ink for example, vegetable oil ink, biomass ink, etc. can also be used.
• the ink may be a water-based ink.
• the thickness of the printed layer is, for example, 0.2 to 8 ⁇ m.
• At least one of the first film and the second film has a gas barrier layer. That is, at least one of the first film and the second film includes aluminum foil, a metal vapor deposited layer, an inorganic vapor deposited layer (an inorganic oxide vapor deposited layer (transparent vapor deposited layer)), a polyvinylidene chloride layer, a water-soluble resin, and an inorganic layer. It has a gas barrier layer such as a layer containing a compound, or a layer made of a film made by reacting a metal alkoxide or its hydrolyzate with an isocyanate compound. The gas barrier layer may be provided on one or both surfaces of the first film, and the gas barrier layer may be provided on one or both surfaces of the second film.
• the first film may be a gas barrier film having a printed layer and a gas barrier layer. Furthermore, depending on the application, the first film may have other functional layers such as a concealing layer.
• the thickness of the first film is, for example, 3 to 150 ⁇ m, may be 5 to 60 ⁇ m, or may be 10 to 60 ⁇ m.
• the second film 2 may be a metal film such as aluminum foil or a known resin film used for packaging bags, and may be the same as the first film 1. Further, the second film 2 may be an impact-resistant film, a sealant film, or the like. Examples of impact-resistant films include biaxially stretched resin films such as biaxially stretched nylon films and biaxially stretched polypropylene films. Examples of the sealant film include unstretched resin films such as unstretched polypropylene film and unstretched polyethylene film. The thickness of the second film is, for example, 3 to 150 ⁇ m, may be 5 to 110 ⁇ m, or may be 15 to 60 ⁇ m.
• the laminate may include, for example, a first resin film having gas barrier properties that includes a biaxially stretched resin film and an inorganic vapor deposited layer, and a second resin film that is a non-stretched resin film and has heat sealability.
• the laminate may include, for example, a first resin film having gas barrier properties including a biaxially stretched resin film and an inorganic vapor deposited layer, a second resin film having impact resistance that is a biaxially stretched nylon film, and a non-stretched resin film.
• a third resin film which will be described later and has heat-sealing properties, can be provided.
• the adhesive layer S1 is a cured product of a coating film obtained using a solvent-free adhesive.
• the adhesive layer S1 is formed, for example, by applying a solvent-free adhesive to at least one surface of the first film 1, bonding it to at least one surface of the second film 2, and then curing it. be able to.
• solvent-free adhesives include two-component curing polyurethanes in which an aromatic or aliphatic isocyanate compound having two or more functional groups acts as a curing agent on a main ingredient such as polyester polyol, polyether polyol, or acrylic polyol.
• solvent-free adhesives are adhesives that do not contain organic solvents or water. In such adhesives, each component reacts and is cured by heating or the like (for example, the hydroxyl group of the main ingredient reacts with the isocyanate group of the curing agent), thereby forming an adhesive layer. That is, the adhesive layer is a (reactive) cured product of a two-part curable polyurethane adhesive that is a solvent-free adhesive.
• the equivalent ratio of isocyanate groups in the curing agent to hydroxyl groups in the main ingredient can be set to 0.5 to 5.
• the fact that the adhesive layer was formed using a solvent-free adhesive rather than a solvent-based adhesive can be analyzed by, for example, Fourier transform infrared spectroscopy.
• the thickness of the adhesive layer S1 is, for example, 0.3 to 5.0 ⁇ m, may be 1.0 to 2.5 ⁇ m, or may be 1.2 to 2.0 ⁇ m.
• FIG. 2 is a schematic enlarged view of the cross-sectional view of FIG. This shows that air bubbles 4 remain in the adhesive layer S1 when the films are bonded together.
• bubbles 4 existing in the adhesive layer S1 there are various possible causes of bubbles 4 existing in the adhesive layer S1, such as bubbles caught in the adhesive during adhesive preparation and coating operations, or bubbles caused by the adhesive during coating. Examples include those caused by surface irregularities. Solvent-free adhesives tend to have higher viscosities than solvent-based adhesives. Therefore, it is difficult to remove air bubbles caught during work. In addition, air bubbles tend to remain because the irregularities on the surface of the adhesive, which are caused by living, cavitation, and stringing phenomena during adhesive application, are sandwiched between films without being sufficiently smooth.
• the first film 1 and/or the second film 2 is provided with an inorganic vapor-deposited layer for the purpose of improving barrier properties, it is difficult for air and gas in the bubbles to pass through the inorganic vapor-deposited layer. It becomes more difficult to pass through and desorb the bubbles.
• the air bubbles 4 present in the adhesive layer S1 affect the strength and physical properties of the laminate 10, such as progression of destruction of the adhesive layer due to concentration of stress around the air bubbles during peeling, Examples include deterioration of the adhesive due to stress caused by the difference in coefficient of thermal expansion between the gas in the bubbles and the surrounding adhesive when heated. In reality, it is thought that the air bubbles in the adhesive layer affect the strength and physical properties due to a combination of these mechanisms.
• the present inventors have found that the air bubbles 4 in the adhesive layer S1 generated during the processing process cause a decrease in the strength and physical properties of the laminate.
• the area of the adhesive layer S1 when the adhesive layer S1 is observed from the lamination direction of the laminate is reduced.
• a laminate with excellent strength and physical properties can be obtained by suppressing the area ratio of the bubbles 4 present in S1 (hereinafter referred to as the bubble area ratio) to a certain value or less, and have completed the present invention.
• the bubble area ratio the area ratio of the bubbles 4 present in S1
• the above-mentioned bubble area ratio is 4% or less, so that practically sufficient strength and physical properties of the laminate can be obtained. If the bubble area ratio exceeds 4%, there is a risk that sufficient strength and physical properties may not be obtained when the laminate is subjected to boiling or retorting. From the above viewpoint, the bubble area ratio can be less than 4%, may be 3% or less, may be 2% or less, and may be 1% or less. From the viewpoint of process suitability and work efficiency, the lower limit of the bubble area ratio can be, for example, 0.1% or more, may be 0.3% or more, or may be 0.5% or more. The bubble area ratio is calculated by the method shown below.
• an image of the laminate is taken from the stacking direction using a transmitted light source of an optical microscope (for example, Microscope VHX-7000 manufactured by Keyence Corporation) and is binarized, and the air bubbles photographed as dark contrast are occupied. Calculate the ratio of the number of pixels to the total number of pixels in the image.
• a known method can be used to set a threshold value during binarization, such as Otsu's binarization method.
• imaging may be performed by focusing on the adhesive layer to be observed.
• the number of bubbles when observing the adhesive layer from the lamination direction of the laminate can be 10 to 90 bubbles/cm 2 , may be 20 to 70 bubbles/cm 2 , and may be 40 to 60 bubbles/cm 2 . It may be cm2 .
• the number of bubbles is at least the above lower limit, it is easy to obtain good process suitability and work efficiency, and when it is below the above upper limit, it is easy to obtain excellent strength and physical properties.
• the number of bubbles having an area of 0.5 mm2 or more can be 10 bubbles/ cm2 or less, and 5 bubbles/cm2 or less.
• the number may be less than or equal to cm 2 , and may be 0 pieces/cm 2 .
• the number of these bubbles is calculated by the method shown below.
• the number of bubbles (number per unit area) is determined by counting the number of bubbles present in the entire measurement target area using the binarized image obtained when calculating the bubble area ratio. The measurement is performed at six randomly selected locations from the laminate, and the average value of the respective counts is taken as the number of bubbles.
• the number of large bubbles (number per unit area) is calculated by calculating the area from the number of pixels occupied by each bubble using the binarized image obtained when calculating the bubble area ratio, and calculating the number of large bubbles present in the entire measurement target area. Count the number of. The measurement is performed at six randomly selected locations from the laminate, and the average value of each count is taken as the number of large bubbles.
• the average diameter of the bubbles when observing the adhesive layer from the lamination direction of the laminate can be 400 ⁇ m or less, may be 300 ⁇ m or less, may be 200 ⁇ m or less, and may be 100 ⁇ m or less. This makes it easy to obtain excellent strength and physical properties.
• the lower limit of the average diameter of the bubbles can be set to, for example, 50 ⁇ m from the viewpoint of process suitability and work efficiency.
• the average bubble diameter is calculated by the method shown below.
• the diameters (longer diameters) of 10 bubbles are measured from an image taken of the laminate from the stacking direction using a transmitted light source of an optical microscope (for example, Keyence Microscope VHX-7000). Let the average value of each diameter be the average bubble diameter.
• imaging may be performed by focusing on the adhesive layer to be observed.
• the ratio of the average diameter of the bubbles in the lamination direction of the laminate to the thickness of the adhesive layer may be 1.5 or less. It may be 1.3 or less, and may be 1.1 or less. This prevents deterioration of the adhesive layer and peeling of the film from the adhesive layer due to stress caused by the difference in coefficient of thermal expansion between the gas in the bubbles and the surrounding adhesive when heat is applied. Furthermore, poor appearance due to swelling of the film is less likely to occur.
• the above ratio of more than 1 means that there are bubbles that are thicker than the thickness of the adhesive layer.
• the lower limit of the above ratio can be, for example, 0.8 or more from the viewpoint of process suitability and work efficiency. The above ratio is calculated by the method shown below.
• Method for calculating the average bubble diameter/adhesive layer thickness ratio Using an optical microscope (for example, Keyence Microscope VHX-7000), take a cross-sectional photograph of the laminate, and check the thickness of the adhesive layer (where no air bubbles are formed) and the presence of air bubbles in the lamination direction of the laminate. From the average diameter, the ratio of the average diameter of the bubbles to the thickness of the adhesive layer is calculated. The average diameter of the bubbles is determined from the diameters of 10 randomly selected bubbles.
• the first suppression method is based on the viewpoint of suppressing the occurrence of unevenness on the surface of the adhesive, such as reducing the amount of adhesive applied, increasing the processing temperature to lower the viscosity of the adhesive, and reducing the amount of adhesive applied. Examples include lowering the coating speed to encourage leveling of the adhesive. From the viewpoint of process suitability and work efficiency, it is preferable to reduce the amount of adhesive applied.
• the second suppression method is based on the viewpoint of reducing the unevenness that occurs on the adhesive surface, and is caused by increasing the roll temperature at the nip and increasing the nip pressure when bonding films using adhesive. Smooth out unevenness by increasing the amount of heat applied by lowering the adhesive application speed and increasing the amount of heat applied by increasing the time in contact with the roll at the nip, or smooth out unevenness by increasing the pressure during winding. For example, methods include ensuring sufficient curing time at relatively low temperatures to smooth out unevenness.
• one of the causes of bubbles 4 is bubbles caught in the adhesive, and by taking measures based on the above points, it is possible to increase the smoothness of the adhesive surface and reduce the amount of bubbles caught in the adhesive. The amount can be reduced.
• the adhesive may generate gas during its curing process.
• the adhesive component reacts with moisture in the air, generating reactive gas such as carbon dioxide gas. Due to the generation of this reactive gas, air bubbles may be included in the adhesive after bonding (after the curing reaction). Such bubbles may also cause a decrease in strength properties (laminate strength, impact strength, etc.).
• the above-described suppression method makes it easier to deal with bubbles originating from the reaction gas.
• FIG. 3 is a schematic cross-sectional view showing another embodiment of the laminate of the present invention.
• the laminate 20 shown in FIG. 3 includes a third film 3 in addition to the first film 1 and the second film 2.
• the third film 3 is placed on the second film 2 (that is, on the opposite side of the second film 2 to the first film 1) with another adhesive layer S2 interposed therebetween.
• the laminate 20 in FIG. 3 includes a first film 1, an adhesive layer S1, a second film 2, another adhesive layer S2, and a third film 3 in this order.
• the second film 2 and the third film 3 are laminated via an adhesive layer S1 that adheres them together, and another adhesive layer S2 that adheres them together.
• the laminate 20 is made of films other than the first film and the second film in order to provide mechanical strength, barrier properties, light resistance, unsealability, heat sealability, etc. required for the packaging bag. It may further include one or more other films (third film 3 in FIG. 3).
• the other film may be placed on the side of the second film opposite to the first film, or on the side of the first film opposite to the second film.
• the type of other film is not particularly limited, and those exemplified as the second film can be used, and in particular, a film without a gas barrier layer can be used.
• the laminate includes a sealant film, it is preferable that the film constituting the outermost layer (one of the two outermost layers) of the laminate is a sealant film.
• another adhesive layer (another adhesive layer S2 in FIG. 3) may be used for laminating other films.
• the details of the other adhesive layer used for laminating other films may be the same as the adhesive layer S1 between the first film 1 and the second film 2.
• a method for manufacturing a laminate includes a first film, an adhesive layer, and a second film in this order, wherein at least one of the first film and the second film has a gas barrier layer.
• the process includes a lamination step in which the first film and the second film are bonded together via a solvent-free two-component curing polyurethane adhesive to obtain a laminate, and the laminate is heated at 25 to 80°C. a curing step of curing to obtain a laminate.
• the adhesive layer is observed from the lamination direction of the laminate, the area ratio of air bubbles based on the area of the adhesive layer is 4% or less.
• lamination process In the lamination step, first, a solvent-free two-component curing polyurethane adhesive is applied to one surface of the first film or the second film. Thereafter, the adhesive-coated surface of one film is made to face the other film, which is not coated with adhesive, and the films are bonded together.
• the lamination step can be performed using a processing device equipped with a delivery roll and a take-up roll, and specifically, can be performed using a forward transfer type coating device or a reverse transfer type coating device (reverse coater).
• a processing device equipped with a delivery roll and a take-up roll can be performed using a forward transfer type coating device or a reverse transfer type coating device (reverse coater).
• reverse coater reverse transfer type coating device
• the first film is sent out from a delivery roll, and the adhesive is applied to one surface of the first film using a roll coater or the like. Then, the adhesive-coated surface of the first film is bonded to one surface of the second film fed out from the other feeding roll.
• the laminate in which the films are bonded together in this manner is wound up with a take-up roll.
• the processing speed by the processing device can be 50 m/min or more from the viewpoint of process suitability and work efficiency, and may be 75 m/min or more.
• the upper limit of the processing speed can be 200 m/min or less, and may be 150 m/min or less, from the viewpoint of suppressing the occurrence of unevenness on the adhesive surface.
• the printing pressure (impression cylinder roll) by the processing device can be set to 0.3 MPa or more from the viewpoint of reducing unevenness generated on the adhesive surface.
• the upper limit of the printing pressure can be 0.55 MPa or less from the viewpoint of process suitability and work efficiency, and may be 0.5 MPa or less.
• the temperature of the lamirol by the processing equipment can be set to 50°C or higher from the viewpoint of reducing unevenness generated on the adhesive surface, and the upper limit of the lamirol temperature can be set to 80°C or lower from the viewpoint of process suitability and work efficiency. .
• the lamirol nip pressure by the processing device can be set to 0.3 MPa or more from the viewpoint of reducing unevenness generated on the adhesive surface.
• the upper limit of the lamirol nip pressure can be 0.55 MPa or less from the viewpoint of process suitability and work efficiency, and may be 0.5 MPa or less.
• the temperature of the adhesive during coating can be 35°C or higher from the viewpoint of lowering the viscosity, and may be 40°C or higher.
• the upper limit of the temperature is not particularly limited, but from the viewpoint of pot life it can be 100°C or lower, may be 90°C or lower, or may be 85°C or lower.
• a solvent-free adhesive that does not use a solvent has a certain degree of viscosity.
• the viscosity of the adhesive during coating can be 300 mPa ⁇ s or more, or 500 mPa ⁇ s or more at 80°C.
• the upper limit of the viscosity is not particularly limited, but from the viewpoint of coating suitability, it is preferably 2000 mPa ⁇ s or less, more preferably 1000 mPa ⁇ s or less.
• the amount of adhesive applied can be 0.5 g/m 2 or more from the viewpoint of adhesive strength, may be 1 g/m 2 or more, or may be 1.5 g/m 2 or more.
• the amount of adhesive applied can be 2.5 g/m 2 or less, and may be 2 g/m 2 or less, from the viewpoint of suppressing the occurrence of unevenness on the adhesive surface.
• the laminate obtained in the lamination process is cured (left) in an environment of 25 to 80°C.
• the curing process can also be called an aging process.
• the curing temperature may be adjusted as appropriate depending on the components of the adhesive.
• the adhesive is cured, and a laminate in which the first film and the second film are laminated via the cured adhesive can be obtained.
• the upper limit of the curing temperature is 80°C or less, but it may be 50°C or less, or it may be 40°C or less.
• the curing time can be 1 hour or more, but may also be 12 hours or more, or 24 hours or more.
• the upper limit of the curing time is not particularly limited, but from the viewpoint of manufacturing efficiency of the laminate, it can be set to, for example, about 72 to 192 hours.
• the laminate for packaging material further includes a third film
• the surface of the laminate of the first film and the second film on the first film side or the surface on the second film side A third film may be laminated thereon via an adhesive.
• the third film may be laminated before or after the laminate of the first film and the second film is cured.
• a packaging film according to one embodiment of the present invention includes the laminate (for example, laminate 10 or 20) of the above embodiment.
• the packaging film is, for example, a film whose innermost layer is made of a sealant film.
• a packaging bag can be manufactured by bonding the sealant films of the packaging film having such a configuration and performing bag-making processing.
• the laminate 10 or 20 described above can be suitably used, for example, to form a packaging bag (for example, a flexible bag) for packaging contents.
• a packaging bag for example, a flexible bag
• the laminate can be used as it is as a packaging film.
• a sealant film can be attached to the laminate to form a packaging film.
• a packaging bag can be manufactured by bonding sealant films of a packaging film including a laminate together and performing bag-making processing. Examples of the contents include liquid seasonings, toiletries, soups, liquid detergents and other liquids, boiled foods and other solids, and curry and other liquid and solid mixtures.
• the packaging bag of this embodiment is a packaging bag made from a packaging film containing the laminate of the above embodiment.
• Examples of the packaging bag include a flat pouch-shaped packaging bag and a self-supporting packaging bag (standing pouch).
• a flat pouch-shaped packaging bag is made by, for example, folding a sheet of packaging film (packaging film containing a sealant film) in half so that the sealant film faces each other, and then heat-sealing the three sides to form a bag shape. It may be a bag shape by stacking two packaging films (packaging films including a sealant film) so that the sealant films face each other and then heat-sealing the four sides. .
• a self-supporting packaging bag is made by placing two packaging films (packaging films containing a sealant film) facing each other, and placing one packaging film (packaging film containing a sealant film) between these films. After stacking a total of three packaging films by folding them in half so that they face outward and inserting them, the packaging films may be heat-sealed on four sides to form a bag shape.
• packaging bag of this embodiment is made of the laminate of the above embodiment which has excellent strength and physical properties, and can be suitably used for boiling and retort applications.
• Example 1 First film (film with gas barrier properties) consisting of printed transparent vapor-deposited barrier film "GL-ARH” (manufactured by Toppan Printing Co., Ltd., thickness 12 ⁇ m), ONY film “ONMB-RT” (manufactured by Unitika Co., Ltd.) , thickness 15 ⁇ m) (impact-resistant film), and a third film (heat sealable film) consisting of PP sealant film “ZK207” (manufactured by Toray Film Processing Co., Ltd., thickness 60 ⁇ m).
• a laminate was manufactured by laminating the following films (having properties) in this order. Lamination processing was performed so that the printed layer of the first film and the second film faced each other.
• a mixture of solvent-free adhesive "TSN-4864A/TSN-4864B3" manufactured by Toyo Morton Co., Ltd.
• the solvent-free adhesive was coated with a roll coater at an adhesive temperature of 80°C (viscosity of approximately 600 mPa ⁇ s) under the processing conditions shown in Table 1 (the adhesive between the first film and the second film layer S1 and the other adhesive layer S2 between the second film and the third film (common).
• the printing layer was previously provided on the laminate surface (the surface on the inorganic vapor deposition layer side) of "GL-ARH" by gravure printing.
• the color ink used was "Rio Alpha White” manufactured by Toyo Ink Co., Ltd.
• the printed pattern is arranged in the following order in the width direction of a 350 mm wide film: unprinted area 50 mm wide, white 50 mm wide, unprinted area 150 mm wide, white 50 mm wide, unprinted area 50 mm wide, and colored ink.
• a uniform strip-shaped pattern with a thickness of 1 ⁇ m was made continuous in the flow direction.
• the diameters (longer diameters) of 10 bubbles were measured from an image taken of the laminate from the stacking direction using a transmitted light source of a microscope VHX-7000 manufactured by Keyence Corporation. The average value of each diameter was defined as the average bubble diameter.
• the laminate was cut parallel to the lamination direction using a microtome.
• a cross-sectional photograph of the adhesive layer was taken using a Keyence Microscope VHX-7000, and the thickness b of the adhesive layer (where no air bubbles were formed) and the average diameter a of air bubbles in the lamination direction of the laminate were measured. From this, the ratio a/b of the average diameter a of the bubbles to the thickness b of the adhesive layer was calculated.
• the average bubble diameter a was determined from the diameters of 10 randomly selected bubbles.
• the laminate was folded in half with the PP sealant film side facing inside, and the two sides were heat-sealed to form a bag.
• the size of the bag was 297 mm x 420 mm.
• the remaining side was similarly heat-sealed to prepare a sample while preventing air from entering.
• the sample was immersed in hot water at 95°C for 90 minutes, boiled, taken out, cooled, and the contents were discharged. The sample was cut out from the unprinted part into a strip of 15 mm in the width direction and 50 mm in the machine direction.
• the lamination strength between -ARH and the ONY film was measured at a peeling speed of 300 mm/min and a peeling angle of 90 degrees, and evaluated using the following index.
• the laminate strength of samples subjected to retort treatment at 135° C. for 40 minutes was similarly measured and evaluated using the following index. ⁇ : Less than 1N/15mm ⁇ : 1N/15mm or more, less than 2N/15mm ⁇ : 2N/15mm or more
• the laminate of the example has no evaluation items of "x" in any of the evaluation items of appearance and laminate strength, indicating that it is a laminate with good appearance and excellent strength and physical properties. was confirmed. From the results in Tables 2 and 3, it is understood that the present invention solves the problem that was not found when bonding non-gas barrier films together using a solvent-free adhesive.

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• 2023
  • 2023-08-21 JP JP2024507870A patent/JPWO2024048347A1/ja active Pending
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