CN116568495A - Laminate, packaging bag, and self-standing pouch - Google Patents

Abstract

A laminate according to an aspect of the present disclosure includes: a substrate layer; a sealant layer; and an adhesive layer disposed between and in contact with the substrate layer and the sealant layer, wherein the substrate layer is composed of a material having a density of 0.940g/cm ³ The above unstretched film mainly composed of polyethylene is formed, and the sealant layer is formed of an unstretched film mainly composed of polyethylene, and the content of polyethylene in the laminate is 90 mass% or more.

Description

Laminate, packaging bag, and self-standing pouch

Technical Field

The present disclosure relates to laminates, packaging bags, and stand-up pouches. More specifically, the present disclosure relates to a laminate excellent in recyclability, and a packaging bag and a self-standing pouch using the laminate.

Background

A laminate comprising a biaxially stretched PET (polyethylene terephthalate) film having excellent heat resistance and toughness as a base film and a polyolefin film such as polyethylene or polypropylene as a sealant layer is known (for example, refer to patent document 1).

In addition, as the demand for construction of a circulating society increases, packaging materials having high recyclability are demanded. In general, it is considered that the recycling property is high when the proportion of the main resin contained in the packaging material is 90 mass% or more, but the conventional packaging material is constituted by a plurality of resin materials and does not satisfy the standard, so that the recycling is not performed at present.

In view of this problem, patent document 2 describes that the base material and the heat seal layer are made of polyethylene in a laminate including the base material, the adhesive layer and the heat seal layer. The above criteria are easily met by constructing the substrate and heat seal layer of the same material. As the base material, a stretched polyethylene film was used.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2017-178357

Patent document 2: japanese patent laid-open No. 2020-55157

Disclosure of Invention

Technical problem to be solved by the invention

[ first object ]

However, in recent years, due to the rising environmental awareness of the problem of marine plastic waste, etc., further improvement in efficiency of classification recycling and recycling of plastic materials has been demanded. That is, in the packaging laminate which has been conventionally improved in performance by combining various materials, a single material has been demanded.

In order to realize a single material in the laminate, it is necessary to make the constituent films of the same material. For example, polyethylene film, which is one of polyolefin films, is widely used as a packaging material, and thus it is expected to make use of a single material of the polyethylene film.

When the packaging material is formed into a single material using a polyethylene film, a stretched polyethylene film is used as the polyethylene film for the surface base material from the viewpoints of printing suitability and bag making suitability. However, the stretched polyethylene film has a problem that adhesion to other layers to be laminated is low and peeling is easy. Therefore, a packaging material which has been made into a single material by using a polyethylene film can be used only in a light packaging material which does not require high adhesion.

The present disclosure has been made in view of the problems of the prior art described above, and a first object thereof is to provide a laminate useful for realizing a single material using a polyethylene film and having excellent adhesion strength and bag making suitability, and a packaging bag using the laminate.

[ second object ]

The inventors found that when the laminate described in patent document 2 is applied to a packaging bag, a self-standing bag, or the like, impact resistance may be insufficient. The inventors have solved this problem while maintaining high recyclability.

A second object of the present disclosure is to provide a laminate which has sufficient impact resistance and is easily recycled when applied to a packaging bag, a self-standing bag, or the like.

Means for solving the technical problems

First aspect

In order to achieve the first object, the present disclosure provides a laminate comprising: a substrate layer; a sealant layer; and an adhesive layer disposed between the base material layer and the sealant layer and in contact with the sealant layer, wherein the base material layer is composed of a material having a density of 0.940g/cm ³ The above-mentioned unstretched film mainly composed of polyethylene is formed, and the above-mentioned sealant layer is formed from an unstretched film mainly composed of polyethylene, and the content of polyethylene in the above-mentioned laminate is 90% by mass or more.

According to the laminate, by using an unstretched film mainly composed of polyethylene in the base layer, good adhesion between the base layer and other layers can be obtained. In addition, the passing structureThe density of the polyethylene forming the substrate layer was 0.940g/cm ³ As described above, the bag making suitability and printing suitability become good. Further, by using an unstretched film containing polyethylene as a main component in the sealant layer, and the polyethylene content in the laminate is 90 mass% or more, a pure polyethylene packaging material having excellent recyclability, which is formed into a single material by using the polyethylene film, can be provided. Further, the laminate has improved adhesion strength and strength as a packaging material by using an unstretched polyethylene film for the base material layer, and therefore, even when a bag such as a self-standing bag is formed in which the content is filled with a liquid, the occurrence of bag breakage when the bag falls can be suppressed.

The laminate may further include a gas barrier layer disposed between the base material layer and the adhesive layer. The gas barrier layer is provided in the laminate, so that the gas barrier property of the laminate is improved.

The gas barrier layer may further comprise a vapor deposition layer. The vapor deposition layer may further include silicon oxide. The gas barrier layer may further include a gas barrier coating layer containing a water-soluble polymer. The gas barrier layer further improves the gas barrier property of the laminate by including the vapor deposition layer or the gas barrier coating layer.

The adhesive layer may be a layer formed of a cured product of a gas barrier adhesive. At this time, the gas barrier property of the laminate is further improved.

The laminate may further include a printed layer disposed between the base layer and the sealant layer. The laminate may further include a resin layer disposed between the base layer and the sealant layer and formed of an unstretched film mainly composed of polyethylene.

In the gas barrier laminate, the difference in the hot melt adhesion temperature between the base material layer and the sealant layer may be 10 ℃ or higher. By providing a difference in hot melt adhesion temperature of 10 ℃ or higher between the base material layer and the sealant layer, the bag making suitability is further improved, and the laminate can be easily formed into a packaging bag or the like by heat sealing.

The present disclosure also provides a packaging bag obtained by bagging the laminate of the present disclosure. The above packaging bag can also be boiled.

Second aspect

In order to achieve the second object, a first aspect of the present disclosure provides a laminate comprising: a substrate layer; an adhesive layer provided on the first surface side of the base material layer; and a sealant layer bonded to the adhesive layer. The base layer and the sealant layer are unstretched films containing polyethylene as a main component, and the polyethylene accounts for 90 mass% or more of the laminate.

A second aspect of the present disclosure is a packaging bag formed by joining sealant layers using the laminate of the first aspect.

A third aspect of the present disclosure is a self-standing pouch formed by joining sealant layers using the laminate of the first aspect.

Effects of the invention

According to the first aspect of the present disclosure, a laminate useful for realizing a single material using a polyethylene film and having excellent adhesion strength and bag making suitability, and a packaging bag using the laminate can be provided.

According to the second aspect of the present disclosure, a laminate which has sufficient impact resistance and is easily recycled when applied to a packaging bag, a self-standing pouch, or the like, and a packaging bag and a self-standing pouch using the laminate can be provided.

Drawings

Fig. 1 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 2 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 3 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 4 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 5 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 6 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 7 is a schematic cross-sectional view showing a laminate according to an embodiment.

Fig. 8 is a schematic cross-sectional view showing a stand-up pouch according to an embodiment.

Fig. 9 is a schematic cross-sectional view showing a laminate according to an embodiment.

Detailed Description

Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings, as the case may be. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and repetitive description thereof will be omitted. The dimensional ratios in the drawings are not limited to the ratios shown in the drawings.

In the following description, the constitution of the first aspect is also applicable to the second aspect, and the constitution of the second aspect is also applicable to the first aspect.

First aspect

< laminate >

Fig. 1 is a schematic cross-sectional view showing a laminate according to an embodiment. The laminate 100 shown in fig. 1 includes a base layer 1, an adhesive layer 2, and a sealant layer 3 in this order.

Fig. 2 is a schematic cross-sectional view showing a laminate according to another embodiment. The laminate 200 shown in fig. 2 further includes a print layer 4 between the base layer 1 and the adhesive layer 2 of the laminate 100 shown in fig. 1.

Fig. 3 is a schematic cross-sectional view showing a laminate according to still another embodiment. The laminate 300 shown in fig. 3 includes, in order, a base layer 1, an undercoat layer 5, a gas barrier layer 10 formed of a vapor deposition layer 6, an adhesive layer 2, and a sealant layer 3.

Fig. 4 is a schematic cross-sectional view showing a laminate according to still another embodiment. The laminate 400 shown in fig. 4 has the same structure as the laminate 300 shown in fig. 3, except that the gas barrier layer 10 is formed of the vapor deposition layer 6 and the gas barrier coating layer 7.

Fig. 5 is a schematic cross-sectional view showing a laminate according to still another embodiment. The laminate 500 shown in fig. 5 further includes a print layer 4 between the gas barrier layer 10 and the adhesive layer 2 of the laminate 400 shown in fig. 4.

Fig. 6 is a schematic cross-sectional view showing a laminate according to still another embodiment. The laminate 600 shown in fig. 6 includes, in order, a base material layer 1, a print layer 4, an adhesive layer 9, a resin layer 8, an undercoat layer 5, a gas barrier layer 10 formed of a vapor deposition layer 6, an adhesive layer 2, and a sealant layer 3.

In the laminated body 100, 200, 300, 400, 500, 600, the base material layer 1 and the sealant layer 3 are each formed of an unstretched film containing polyethylene as a main component. In the laminate 600, the resin layer 8 is formed of an unstretched film mainly composed of polyethylene. The "main component" herein means a component having a content of 50 mass% or more in the unstretched film. In the laminated body 100, 200, 300, 400, 500, 600, the base material layer 1 is one outermost layer of the laminated body, and the sealant layer is the other outermost layer of the laminated body. The layers constituting the laminate will be described below.

[ substrate layer 1]

The base material layer 1 is a layer serving as a support and has a density of 0.940g/cm ³ An unstretched film comprising the polyethylene as a main component is formed. The polyethylene content in the base material layer 1 may be 50 mass% or more, 80 mass% or more, or 100 mass% or more based on the total amount of the base material layer 1. From the viewpoint of recyclability, polyethylene is preferably used as the material of the base material layer 1. In addition, the higher the polyethylene content in the base material layer 1, the higher the recyclability.

The polyethylene contained in the base material layer 1 may be an acid-modified polyethylene obtained by graft-modifying polyethylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.

The polyethylene contained in the base material layer 1 had a density of 0.940g/cm ³ The above, preferably 0.945g/cm ³ The above, more preferably 0.950g/cm ³ The above. The density of the polyethylene was 0.940g/cm ³ In the above, when the laminate is formed into a bag shape, the sealing agent layer 3 alone is easily melt-bonded at the time of heat sealing, and therefore, the bag-making suitability is improved. In addition, when the density of the polyethylene is 0.940g/cm ³ In the above manner, when the print layer 4 is formed on the base material layer 1, the printability becomes good. In addition, the density of the polyethylene The degree of the reaction is 0.940g/cm ³ In the above, the substrate layer 1 is easily prevented from being stretched to generate wrinkles in the roll processing, and when the vapor deposition layer 6 is provided on the substrate layer 1, the occurrence of cracks in the vapor deposition layer 6 is easily prevented.

The base material layer 1 may be a multilayer structure including a plurality of unstretched films each including polyethylene having different densities as a main component. The base material layer 1 is preferably multilayered in view of suitability for processing, rigidity or stiffness strength, heat resistance, powder falling during conveyance, and the like of the film constituting the base material layer 1. In addition, when the density of the film as the base material layer 1 is measured, the density needs to be 0.940g/cm ³ The above. The layers may be laminated by changing the content of the slip agent, antistatic agent, or the like. The base material layer 1 having a plurality of layers may be laminated by extrusion coating, coextrusion coating, sheet molding, coextrusion blow molding, or the like to form a film. The total thickness of the base material layer 1 having a plurality of layers is preferably about 10 to 100. Mu.m, more preferably 15 to 50. Mu.m.

The molecular orientation degree (MOR) of the unstretched film constituting the base layer 1 may be 1.07 or less, may be 1.05 or less, or may be 1.04 or less. The lower the degree of molecular orientation, the more excellent the isotropy of the film. When the molecular orientation is 1.07 or less, the adhesion (peeling resistance) of the base material layer 1 in the laminate is easily improved. The degree of molecular orientation can be measured by a molecular orientation meter.

The heat shrinkage of the base material layer 1 in the advancing direction (MD direction) and the perpendicular direction (TD direction) after heating at 100 ℃ for 15 minutes is preferably 3% or less, more preferably 2% or less, and still more preferably 1.5% or less. When the heat shrinkage ratio of the base material layer 1 is within the above range, the base material layer 1 is easily suppressed from stretching to generate wrinkles in the roll processing, and the vapor deposition layer 6 is easily suppressed from generating cracks.

Here, the heat shrinkage (%) is a value calculated by the following formula.

The measurement sequence of the heat shrinkage (%) = { (length before heating-length after heating)/length before heating } ×100 heat shrinkage is as follows.

(1) The substrate layer 1 was cut into 20cm×20cm as a measurement sample.

(2) A line of 10cm (length before heating) was drawn in the MD or TD of the measurement sample.

(3) The assay sample was heated at 100℃for 15 minutes.

(4) The length (length after heating) of the drawn line in the MD direction or the TD direction was measured.

(5) The heat shrinkage was calculated using the above formula.

The thickness of the base material layer 1 is not particularly limited. The thickness may be set to 6 to 200. Mu.m, or 9 to 50. Mu.m, or 12 to 38. Mu.m, from the viewpoint of obtaining excellent impact resistance and excellent bag-making suitability, depending on the application.

The base material layer 1 may be subjected to various pretreatment such as corona treatment, plasma treatment, low-temperature plasma treatment, flame treatment, chemical agent treatment, solvent treatment, ozone treatment, or the like, or may be provided with a coating layer such as an easy-to-adhere layer, in order to improve adhesion to the adhesive layer 2, the print layer 4, the undercoat layer 5, or the vapor deposition layer 6, in a range not to impair barrier performance.

The base material layer 1 may further contain additives such as fillers, anti-blocking agents, antistatic agents, plasticizers, lubricants, antioxidants, and the like. These additives may be used singly or in combination of 2 or more.

[ bottom coating 5]

An undercoat layer (anchor coat layer) 5 may be provided on the surface of the laminated vapor deposition layer 6 of the base material layer 1. The primer layer 5 has effects of improving adhesion between the base material layer 1 and the vapor deposition layer 6, improving smoothness of the surface of the base material layer 1, and suppressing cracking of the vapor deposition layer 6 due to stretching of the base material layer 1. Further, the smoothness is improved, so that the vapor deposition layer 6 is easily and uniformly formed without defects, and a high barrier property is easily exhibited. The primer layer 5 may be formed using a primer layer forming composition (anchor coat).

Examples of the resin used for the anchor coating agent include acrylic resins, epoxy resins, urethane acrylate resins, polyester polyurethane resins, polyether polyurethane resins, and the like. The resin used in the anchor coating agent is preferably an acrylic urethane resin or a polyester urethane resin from the viewpoints of heat resistance and interlayer adhesion strength. The primer layer 5 may be formed using an anchor coating agent containing these resins or containing a component that reacts to form these resins.

The thickness of the undercoat layer 5 is not particularly limited, but is preferably in the range of 0.01 to 5. Mu.m, more preferably in the range of 0.03 to 3. Mu.m, and particularly preferably in the range of 0.05 to 2. Mu.m. When the thickness of the undercoat layer 2 is equal to or greater than the lower limit, the interlayer adhesion strength tends to be more sufficient, and when it is equal to or less than the upper limit, the desired gas barrier property tends to be easily exhibited.

As a method for coating the primer layer 5 on the base material layer 1, a known coating method can be used without particular limitation, and examples thereof include dipping methods; a method using a sprayer, a coater, a printer, a brush, or the like. Examples of the type of the coater and the printer used in these methods and the coating method thereof include gravure coaters such as direct gravure coater, reverse gravure coater, contact reverse gravure coater, offset gravure coater, reverse roll coater, micro gravure coater, closed blade coater, air knife coater, dip coater, bar coater, comma roll coater, die coater, and the like.

As the coating amount of the undercoat layer 5, the anchor coating agent was applied and dried every 1m ² Preferably 0.01 to 5g/m ² More preferably 0.03 to 3g/m ² . Every 1m after the anchor coating is coated and dried ² When the mass of (b) is equal to or more than the lower limit, film formation tends to be sufficient, and when it is equal to or less than the upper limit, sufficient drying tends to be facilitated, and solvent is less likely to remain.

The method for drying the undercoat layer 5 is not particularly limited, and a method using natural drying can be mentioned; a method of drying the mixture in an oven set to a predetermined temperature; a method using a dryer attached to the coater, such as an arch dryer, a suspension dryer, a drum dryer, or an infrared dryer. Further, the drying conditions may be appropriately selected depending on the method of drying the material, and for example, in the method of drying the material in an oven, drying at a temperature of 60 to 100℃for about 1 second to 2 minutes is preferable.

As the primer layer 5, a polyvinyl alcohol resin may be used instead of the resin described above. The polyvinyl alcohol resin may have a vinyl alcohol unit obtained by saponification of a vinyl ester unit, and examples thereof include polyvinyl alcohol (PVA) and ethylene-vinyl alcohol copolymer (EVOH).

Examples of PVA include resins obtained by homopolymerizing vinyl esters such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, and vinyl neodecanoate, followed by saponification. The PVA may also be a modified PVA which has been subjected to copolymerization modification or post-modification. The modified PVA can be obtained, for example, by copolymerizing a vinyl ester with an unsaturated monomer copolymerizable with the vinyl ester and then saponifying the resulting product. Examples of the unsaturated monomer copolymerizable with the vinyl ester include olefins such as ethylene, propylene, isobutylene, α -octene, α -dodecene, and α -octadecene; hydroxy-containing alpha-olefins such as 3-buten-1-ol, 4-penten-1-ol, 5-hexen-1-ol and the like; unsaturated acids such as acrylic acid, methacrylic acid, crotonic acid, maleic anhydride, itaconic acid, and undecylenic acid; nitriles such as acrylonitrile and methacrylonitrile; amides such as diacetone acrylamide, and methacrylamide; olefin sulfonic acids such as ethylene sulfonic acid, propylene sulfonic acid, and methacrylic sulfonic acid; vinyl compounds such as alkyl vinyl ether, dimethylallyl vinyl ketone, N-vinyl pyrrolidone, vinyl chloride, vinyl ethylene carbonate, 2-dialkyl-4-vinyl-1, 3-dioxolane, glycerol monoallyl ether, and 3, 4-diacetoxy-1-butene; vinylidene chloride, 1, 4-diacetoxy-2-butene, vinylene carbonate, and the like.

The polymerization degree of PVA is preferably 300 to 3000. When the polymerization degree is 300 or more, the barrier property tends to be improved, and when it is 3000 or less, the viscosity tends to be suppressed from being excessively high, and the coating suitability tends to be lowered. The saponification degree of PVA is preferably 90 mol% or more, more preferably 95 mol% or more, and still more preferably 99 mol% or more. The saponification degree of PVA may be 100 mol% or less, or 99.9 mol% or less. The polymerization degree and saponification degree of PVA can be measured according to the method described in JIS K6726 (1994).

EVOH is generally obtained by saponifying a copolymer of ethylene with an acid vinyl ester such as vinyl acetate, vinyl formate, vinyl propionate, vinyl valerate, vinyl caprate, vinyl laurate, vinyl stearate, vinyl pivalate, or vinyl neodecanoate.

The polymerization degree of EVOH is preferably 300 to 3000. When the polymerization degree is 300 or more, the barrier property tends to be improved, and when it is 3000 or less, the viscosity tends to be suppressed from being excessively high, and the coating suitability tends to be lowered. The saponification degree of the vinyl ester component of the EVOH is preferably 90 mol% or more, more preferably 95 mol% or more, and still more preferably 99 mol% or more. The saponification degree of the EVOH may be 100 mol% or less, or 99.9 mol% or less. The saponification degree of EVOH was obtained as follows: nuclear magnetic resonance ¹ H-NMR) was determined from the peak area of the hydrogen atom contained in the vinyl ester structure and the peak area of the hydrogen atom contained in the vinyl alcohol structure.

The content of the ethylenic unit in the EVOH is 10 mol% or more, more preferably 15 mol% or more, still more preferably 20 mol% or more, and particularly preferably 25 mol% or more. The content of the ethylenic unit in the EVOH is preferably 65 mol% or less, more preferably 55 mol% or less, and still more preferably 50 mol% or less. When the content of the ethylenic unit is 10 mol% or more, the gas barrier property and dimensional stability at high humidity can be well maintained. When the content of the ethylenic unit is 65 mol% or less, the gas barrier property can be improved. The content of the ethylenic unit in EVOH can be determined by NMR.

When a polyvinyl alcohol resin is used as the primer layer 5, examples of a method for forming the primer layer 5 include coating using a polyvinyl alcohol resin solution, multilayer extrusion, and the like.

[ vapor deposition layer 6]

Examples of the constituent material of the deposition layer 6 include inorganic oxides such as alumina, silica, magnesia, and tin oxide. From the viewpoint of transparency and barrier properties, the inorganic oxide may be selected from alumina, silica, and magnesia. In addition, from the viewpoint of excellent tensile ductility during processing, the deposition layer 6 is preferably a layer containing silicon oxide. By using the vapor deposition layer 6, high barrier properties can be obtained with an extremely thin layer in a range that does not affect the recyclability of the laminate.

The O/Si ratio of the deposition layer 6 is preferably 1.7 or more. When the O/Si ratio is 1.7 or more, the content of metallic Si can be easily suppressed to obtain good transparency. The O/Si ratio is preferably 2.0 or less. When the O/Si ratio is 2.0 or less, the crystallinity of SiO is prevented from being improved, and the vapor deposition layer 6 is prevented from becoming excessively hard, whereby good tensile properties can be obtained. This can suppress occurrence of cracks in the vapor deposition layer 6 when the adhesive layer 2 is laminated. In addition, in the packaging bag, the base material layer 1 may shrink by heat generated during the boiling treatment after the molding, but the vapor deposition layer 6 tends to follow the shrinkage due to the O/Si ratio of 2.0 or less, and the reduction in barrier property can be suppressed. From the viewpoint of obtaining these effects more sufficiently, the O/Si ratio of the vapor deposition layer 6 is preferably 1.75 or more and 1.9 or less, more preferably 1.8 or more and 1.85 or less.

The O/Si ratio of the deposition layer 6 can be obtained by X-ray photoelectron spectroscopy (XPS). For example, the measurement device may be an X-ray photoelectron spectroscopic analyzer (trade name: JPS-90MXV, manufactured by Japanese electric Co., ltd.), an X-ray source may be a non-monochromic MgK.alpha. (1253.6 eV), and the measurement may be performed with an X-ray power of 100W (10 kV-10 mA). For quantitative analysis to determine the O/Si ratio, a relative sensitivity factor of 2.28 may be used for O1s, and a relative sensitivity factor of 0.9 may be used for Si2 p.

The thickness of the deposition layer 6 is preferably 10nm to 50 nm. When the film thickness is 10nm or more, sufficient gas barrier properties can be obtained. When the film thickness is 50nm or less, occurrence of cracks due to deformation caused by internal stress of the thin film can be suppressed, and reduction in gas barrier properties can be suppressed. In addition, when the film thickness is 50nm or less, an increase in cost due to an increase in the amount of material used, a long film formation time, and the like is easily suppressed, and thus it is also preferable from an economical point of view. From the same viewpoint as described above, the film thickness of the vapor deposition layer 6 is more preferably 20nm or more and 40nm or less.

The deposition layer 6 can be formed by vacuum deposition, for example. In the vacuum film formation, a physical vapor deposition method or a chemical vapor deposition method may be used. Examples of the physical vapor deposition method include a vacuum deposition method, a sputtering method, and an ion plating method, but are not limited thereto. Examples of the chemical vapor deposition method include a thermal CVD method, a plasma CVD method, and a photo CVD method, but are not limited thereto.

Among the above vacuum film forming methods, a resistance heating type vacuum vapor deposition method, an EB (Electron Beam) heating type vacuum vapor deposition method, an induction heating type vacuum vapor deposition method, a sputtering method, a reactive sputtering method, a dual magnetron sputtering method, a plasma chemical vapor deposition method (PECVD method), or the like is particularly preferably used. However, in view of productivity, the vacuum vapor deposition method is currently most preferable. As the heating means of the vacuum vapor deposition method, any one of an electron beam heating system, a resistance heating system, and an induction heating system is preferably used.

[ adhesive layer 2]

The adhesive layer 2 is provided at a position contacting the sealant layer 3, and adheres the sealant layer 3 to other layers. The other layers are, for example, the base material layer 1, the print layer 4, the vapor deposition layer 6, or the gas barrier coating layer 7.

As the adhesive constituting the adhesive layer 2, a known adhesive can be used. As the material of the adhesive, for example, polyester-isocyanate resin, urethane resin, polyether resin, and the like can be used.

The adhesive layer 2 may be a gas barrier adhesive layer having gas barrier properties. By providing the gas barrier adhesive layer, the gas barrier property of the laminate can be improved. When the laminate does not have the gas barrier coating layer 7, the adhesive layer 2 is preferably a gas barrier adhesive layer. The oxygen permeability of the gas barrier adhesive layer is preferably 150cc/m ² Day atm or less, more preferably 100cc/m ² Day atm or less, more preferably 80cc/m ² Day atm or less, particularly preferably 50cc/m ² Day atm or less. By oxygenThe permeability is within the above range, and the gas barrier property of the laminate can be sufficiently improved. When the gas barrier adhesive layer is provided at a position in contact with the vapor deposition layer 6, the gas barrier adhesive layer is filled into the gap even when slight cracking occurs in the vapor deposition layer 6 by the oxygen permeability falling within the above range, and the decrease in the gas barrier property can be suppressed.

The gas barrier adhesive layer may be a layer formed of a cured product of the gas barrier adhesive. The gas barrier adhesive layer is formed using a gas barrier adhesive that can exhibit gas barrier properties after curing. Examples of the gas barrier adhesive used for forming the gas barrier adhesive layer include epoxy adhesives and polyester-polyurethane adhesives. Specific examples of the GAS barrier adhesive that can exhibit GAS barrier properties after curing include "Maxive" manufactured by mitsubishi GAS chemistry, and "Paslim" manufactured by DIC corporation.

The logarithmic decrement at 30 ℃ of the surface of the gas barrier adhesive layer measured by a rigid pendulum type physical property tester is preferably 0.1 or less, more preferably 0.05 or less, and further preferably 0.03 or less. When the gas barrier adhesive layer is provided at a position in contact with the deposition layer 6, the logarithmic decrement of the surface of the gas barrier adhesive layer falls within the above range, whereby the gas barrier property of the laminate can be further improved and the decrease in the gas barrier property after bending can be further suppressed.

When the gas-barrier adhesive layer is provided at a position in contact with the vapor deposition layer 6, the thickness of the gas-barrier adhesive layer is preferably 50 times or more the thickness of the vapor deposition layer 6. When the thickness of the gas barrier adhesive layer is within the above range, cracking of the deposition layer 6 can be more sufficiently suppressed, and the gas barrier property of the laminate can be further improved. Further, when the thickness of the gas barrier adhesive layer is within the above range, cushioning properties for cushioning external impact can be obtained, and cracking of the vapor deposition layer 6 due to impact can be prevented. On the other hand, the thickness of the gas barrier adhesive layer is preferably 300 times or less the thickness of the vapor deposition layer 6 from the viewpoints of maintenance of flexibility, processing suitability, and cost of the laminate.

The thickness of the adhesive layer 2 is preferably 0.1 to 20. Mu.m, more preferably 0.5 to 10. Mu.m, still more preferably 1 to 5. Mu.m. By setting the thickness of the adhesive layer 2 to the above lower limit or more, the adhesion between the sealant layer 3 and other layers can be further improved. In addition, the thickness of the adhesive layer 2 is not less than the lower limit value, whereby cushioning properties for cushioning external impact can be obtained. On the other hand, the thickness of the adhesive layer 2 is equal to or less than the upper limit, so that flexibility of the laminate tends to be sufficiently maintained.

The adhesive used for forming the adhesive layer 2 may be applied by, for example, bar coating, dipping, roll coating, gravure coating, reverse coating, air knife coating, comma roll coating, die coating, screen printing, spray coating, gravure offset printing, or the like. The temperature of the coating film coated with the adhesive may be, for example, 30 to 200 ℃, preferably 50 to 180 ℃. The temperature at which the coating film is cured may be, for example, room temperature to 70 ℃, preferably 30 to 60 ℃. When the temperature at the time of drying and curing is within the above range, the occurrence of cracks in the vapor deposition layer 6 or the adhesive layer 2 can be further suppressed, and excellent gas barrier properties and excellent adhesion of the sealant layer 3 to other layers can be exhibited.

When the laminate is provided with the vapor deposition layer 6, the adhesive layer 2 and the vapor deposition layer 6 are preferably in direct contact (no other layer is present therebetween) from the viewpoint of preventing cracking of the vapor deposition layer 6. Therefore, the adhesive layer 2 is preferably formed by applying the adhesive to the vapor deposition layer 6, and drying and curing the adhesive. Similarly, the vapor deposition layer 6 and the undercoat layer 5 are preferably in direct contact (no other layer exists therebetween) from the viewpoint of preventing cracking of the vapor deposition layer 6.

[ gas Barrier coating layer 7]

The gas barrier coating layer 7 is a layer for improving the gas barrier property while protecting the vapor deposition layer 6, and thus exhibits a high gas barrier property due to the synergistic effect with the vapor deposition layer 6. The gas barrier coating layer 7 may contain a water-soluble polymer, at least one of a metal alkoxide and a hydrolysate thereof, and at least one of a water-soluble polymer, a metal alkoxide and a hydrolysate thereof. The water-soluble polymer may have a hydroxyl group. The gas barrier coating layer 7 may be formed by a step of forming a coating film containing the above components on the surface of the vapor deposition layer 6.

Examples of the water-soluble polymer include polyvinyl alcohol, polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, and sodium alginate. Among them, polyvinyl alcohol (hereinafter abbreviated as PVA) is preferable because it can make the gas barrier property of the gas barrier coating layer 7 excellent. The PVA mentioned here is generally obtained by saponifying polyvinyl acetate, and for example, so-called partially saponified PVA in which acetic acid groups remain in a few tens%, and complete PVA in which acetic acid groups remain in only a few% can be used. The water-soluble polymer may be hydrolyzed and dehydrated condensed (for example, sol-gel method) together with the metal alkoxide and/or the hydrolysate thereof to form an organic-inorganic composite.

The metal alkoxide is a compound represented by the following general formula.

M(OR) _n

(M represents a metal atom such as Si, ti, al, zr, R represents-CH ₃ 、-C ₂ H ₅ Alkyl, n represents an integer corresponding to the valence of M. )

Specifically, tetraethoxysilane [ Si (OC) ₂ H ₅ ) ₄ ]Triisopropoxyaluminum [ Al (O-iso-C) ₃ H ₇ ) ₃ ]Etc. Tetraethoxysilane and triisopropoxyaluminum are preferable because they are stable in an aqueous solvent after hydrolysis. Examples of the hydrolysates and polymers of metal alkoxides include the following compounds.

Hydrolysis or polymerization of tetraethoxysilane: silicic acid (Si (OH) ₄ ) Etc

Hydrolyzate or polymer of tripropoxy aluminium: aluminum hydroxide (Al (OH) ₃ ) Etc

The gas barrier coating layer 7 may further contain a silane coupling agent. The silane coupling agent may be a compound represented by the following general formula.

R ¹ Si(OR ² ) _n

(R ¹ Represents an organofunctional group, R ² Represents CH ₃ 、C ₂ H ₅ And alkyl groups. )

Specifically, examples thereof include silane coupling agents such as ethyltrimethoxysilane, vinyltrimethoxysilane, γ -chloropropylmethyldimethoxysilane, γ -chloropropyltrimethoxysilane, glycidoxypropyl trimethoxysilane, γ -methacryloxypropyl trimethoxysilane, and γ -methacryloxypropyl methyldimethoxysilane. Further, to the gas barrier coating layer 7, known additives such as an isocyanate compound, a dispersant, a stabilizer, a viscosity regulator, and a colorant may be added as necessary within a range that does not impair the gas barrier property.

The thickness (film thickness) of the gas barrier coating layer 7 is preferably in the range of 50 to 1000nm, more preferably in the range of 100 to 500 nm. When the film thickness is 50nm or more, a more sufficient gas barrier property tends to be obtained, and when it is 1000nm or less, a sufficient flexibility tends to be maintained due to the thin film.

Examples of the solvent used for forming the coating film include water, methanol, ethanol, isopropanol, n-propanol, n-butanol, n-pentanol, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, toluene, hexane, heptane, cyclohexane, acetone, methyl ethyl ketone, diethyl ether, dioxane, tetrahydrofuran, ethyl acetate, and butyl acetate. These solvents may be used alone in an amount of 1 or 2 or more. Among them, methanol, ethanol, isopropyl alcohol, toluene, ethyl acetate, methyl ethyl ketone, and water are preferable from the viewpoint of paintability. From the viewpoint of manufacturability, methanol, ethanol, isopropanol, and water are preferable.

The coating liquid may be optionally added with additives such as isocyanate compounds, silane coupling agents, dispersants, stabilizers, viscosity modifiers, and colorants, within a range that does not impair the gas barrier properties. For example, from the viewpoint of improving hot water resistance, the coating liquid may be added with the formula (R ¹ Si(OR ² ) ₃ ) A silane compound (silane coupling agent) represented by n. Organofunctional groups (R) ¹ ) Preferably a non-aqueous functional group such as vinyl, epoxy, methacryloxy, ureido, isocyanate, and the like. Specific examples of the silane coupling agent include 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate, 3-glycidoxypropyl trimethoxysilane, and 2- (3, 4-epoxycyclohexyl) ethyl trimethoxysilane.

The gas barrier coating layer 7 may be formed by a step of applying a coating liquid to the surface of the vapor deposition layer 6. As the coating method, conventionally known methods such as a casting method, a dipping method, a roll coating method, a gravure coating method, a screen printing method, a reverse coating method, a spray coating method, a sleeve coating method, a die coating method, a metal bar coating method, a closed knife coating method, a curtain coating method, and the like, which are generally used, can be used. The coating film formed by the application of the coating liquid is dried by heating, whereby the gas barrier coating layer 7 can be formed.

[ sealant layer 3]

The sealant layer 3 is a layer formed of an unstretched film mainly composed of polyethylene. The polyethylene content in the sealant layer 3 may be 50 mass% or more, 80 mass% or more, or 100 mass% or more based on the total amount of the sealant layer 3. The sealant layer 3 is a layer for imparting sealability to the laminate by heat sealing.

As a material of the sealant layer 3, specifically, a low density polyethylene resin (LDPE), a medium density polyethylene resin (MDPE), a linear low density polyethylene resin (LLDPE), or the like can be used. These polyethylene resins may be appropriately selected depending on the use and the temperature conditions such as boiling treatment.

The polyethylene contained in the sealant layer 3 may also be an acid-modified polyethylene obtained by graft-modifying polyethylene with an unsaturated carboxylic acid, an acid anhydride of an unsaturated carboxylic acid, an ester of an unsaturated carboxylic acid, or the like.

The polyethylene contained in the sealant layer 3 preferably has a density lower than that of the polyethylene contained in the base material layer 1, more preferably less than 0.94g/cm ³ More preferably 0.90 to 0.925g/cm ³ . By satisfying the above densityIn the case of heat-sealing the laminate to form a bag, only the sealant layer 3 is easily melt-bonded, and thus the bag-making suitability is improved.

The sealant layer 3 may be a multilayer structure including a plurality of unstretched films each including polyethylene having a different density as a main component. The sealant layer 3 may be suitably multilayered in consideration of processing suitability, rigidity or stiffness strength, heat resistance, powder falling during conveyance, and the like of a film constituting the sealant layer 3. In addition, when the density of the film as the sealant layer 3 is measured, the density is preferably smaller than that of the base material layer 1. The layers may be laminated by changing the content of an additive or the like described later. The sealant layer 3 having a plurality of layers may be laminated by extrusion coating, coextrusion coating, sheet molding, coextrusion blow molding, or the like to form a film.

Various additives such as flame retardant, slip agent, anti-blocking agent, antioxidant, light stabilizer, and adhesion imparting agent may be added to the sealant layer 3.

The thickness of the sealant layer 3 may be determined according to the mass of the contents, the shape of the package, and the like, and is preferably about 30 to 150 μm.

As a method for forming the sealant layer 3, a method of adhering an unstretched film mainly composed of polyethylene to an adhesive for forming the adhesive layer 2 is mentioned.

The sealant layer 3 may be subjected to various pretreatment such as corona treatment, plasma treatment, low-temperature plasma treatment, flame treatment, chemical agent treatment, solvent treatment, ozone treatment, etc. on the laminated surface thereof, or may be provided with a coating layer such as an easy-to-adhere layer, from the viewpoint of improving adhesion to the adhesive layer 2.

[ printing layer 4]

The printed layer 4 is provided at a position visible from the outside of the laminate for the purpose of improving display of information related to the contents, identification of the contents, or design of the package. The printing method and the printing ink are not particularly limited, and may be appropriately selected from known printing methods and printing inks in consideration of suitability for printing on films, design properties such as color tone, adhesion, safety as food containers, and the like. As the printing method, for example, a gravure printing method, an offset printing method, a gravure offset printing method, a flexography method, an inkjet printing method, or the like can be used. Among them, the gravure printing method can be preferably used from the viewpoint of productivity or high fineness of the pattern.

In order to improve the adhesion of the printed layer 4, various pretreatment such as corona treatment, plasma treatment, flame treatment, etc. may be applied to the surface of the layer (the base material layer 1 or the resin layer 8) on which the printed layer 4 is formed, or a coating layer such as an easy-to-adhere layer may be provided.

Here, the lamination position of the print layer 4 is not particularly limited. The print layer 4 may be formed on the surface of the base material layer 1 on the sealant layer 3 side, for example. When the laminate is provided with the gas barrier layer 10, the printed layer 4 may be formed on the surface of the gas barrier layer 10 on the sealant layer 3 side. When the laminate includes the resin layer 8, the print layer 4 may be formed on one surface of the resin layer 8. The print layer 4 may be formed on the surface of the base material layer 1 or the resin layer 8 in advance, and the base material layer 1 or the resin layer 8 on which the print layer 4 is formed may be laminated with other layers via the adhesive layer 2 or the adhesive layer 9.

[ resin layer 8]

The resin layer 8 is a layer which is disposed between the base material layer 1 and the sealant layer 3 and is formed of an unstretched film mainly composed of polyethylene. The polyethylene content in the resin layer 8 may be 50 mass% or more, 80 mass% or more, or 100 mass% or more based on the total amount of the resin layer 8. The resin layer 8 may have the same structure as the base material layer 1. By providing the resin layer 8, a laminate having stiffness can be formed. Further, the print layer 4 is provided on one surface of the base material layer 1 and the resin layer 8, and the gas barrier layer 10 is provided on the other surface, so that the base material film forming the print layer 4 and the base material film forming the gas barrier layer 10 can be separated. In this case, the risk of occurrence of defects in forming the printed layer and the risk of occurrence of defects in forming the gas barrier layer can be distinguished, and the step of applying a thermal load to 1 sheet of the base material film can be reduced. In addition, by providing the resin layer 8, it becomes easy to provide the printed layer 4 on the inner surface other than the outer surface of the laminate.

Here, the lamination position of the resin layer 8 is not particularly limited as long as it is between the base material layer 1 and the sealant layer 3. When the laminate is provided with the gas barrier layer 10, the resin layer 8 may be disposed between the gas barrier layer 10 and the base material layer 1. The resin layer 8 may be laminated with other layers via an adhesive layer 9.

[ adhesive layer 9]

As the adhesive constituting the adhesive layer 9, a known adhesive can be used. As the material of the adhesive, for example, polyester-isocyanate resin, urethane resin, polyether resin, and the like can be used. As the adhesive, an adhesive for forming the adhesive layer 2 may be used.

[ thermal fusion bonding temperature of layers ]

In the laminate, the difference in the heat fusion bonding temperature between the base material layer 1 and the sealant layer 3 is preferably 10 ℃ or higher, more preferably 15 ℃ or higher, and still more preferably 20 ℃ or higher. By making the difference in the hot melt bonding temperature within the above range, it becomes easy to form the laminate into a packaging bag or the like by heat sealing.

The heat-fusible bonding temperature of the base material layer 1 is preferably higher than the heat-fusible bonding temperature of the sealant layer, more preferably 100 ℃ or higher, and still more preferably 120 ℃ or higher. When the heat fusion bonding temperature is equal to or higher than the lower limit value, the laminate is easily formed into a packaging bag or the like by heat sealing.

The thermal fusion bonding temperature of the sealant layer 3 is preferably lower than the thermal fusion bonding temperature of the base material layer 1, more preferably 130 ℃ or lower, and still more preferably 110 ℃ or lower. When the heat fusion bonding temperature is equal to or lower than the upper limit, the laminate is easily formed into a packaging bag or the like by heat sealing.

Here, the hot melt bonding temperature of each layer is by the method based on JIS Z0238:1998, heat sealing temperature of the measuring object layer measured by the measuring method. Specifically, 2 measurement object layers were stacked, and a heat seal portion was formed by heating under a pressure of 0.2MPa for 1 second using a heat seal tester, and the lowest temperature at which heat fusion bonding can be performed to form a heat seal portion that was not peeled off was set as the heat fusion bonding temperature.

[ laminate ]

As described above, the films constituting the laminate may be entirely made of polyethylene film. Such a laminate can be said to be a packaging material (of a single material) formed from a single raw material excellent in recyclability. From this viewpoint, the content of polyethylene in the laminate is 90 mass% or more, preferably 92.5 mass% or more.

The thickness of the laminate may be appropriately determined according to the use. The thickness of the laminate may be, for example, 0.01 to 10mm, and preferably 0.1 to 1.0mm.

The laminate preferably has a lamination strength of 2.5N/15mm or more as measured by the peel adhesion strength test method under 180-degree peel (JIS K6854-2, ISO 8510-2) under the condition that the peeling speed is 300 mm/min. By having the lamination strength of 2.5N/15mm or more, even when a bag is formed in which the content is filled with a liquid, breakage of the bag can be suppressed when the bag falls.

The laminate is preferably used for various applications such as packaging products such as containers and bags, sheet-shaped products such as cosmetic sheets and trays, optical films, resin sheets, various label materials, cover materials, and laminate tubes, and particularly preferably used for packaging products. Examples of the packaged product include pillow bags, self-supporting bags, three-side sealed bags, four-side sealed bags, and the like.

< packaging bag >

The packaging bag is obtained by bagging the laminate. The packaging bag may be formed by folding 1 laminate into 2 sheets so that the sealant layers face each other and then heat-sealing 3 sides, or may be formed by folding 2 laminates so that the sealant layers face each other and then heat-sealing 4 sides. The packaging bag can contain contents such as foods and medicines as the contents. The packaging bag may be subjected to heat sterilization such as boiling treatment.

The boiling treatment is generally a method of performing wet heat sterilization for preserving foods, medicines, and the like. The package bag in which the food or the like is packaged is usually subjected to a wet heat sterilization treatment at 60 to 100 ℃ under atmospheric pressure for 10 to 120 minutes, depending on the content. The boiling treatment is usually performed at 100 ℃ or lower using a hot water tank. The method includes a batch type in which the substrate is immersed in a hot water tank at a predetermined temperature and then taken out after being treated for a predetermined period of time; and continuous treatment by tunnel-type feeding in the hot water tank. The package of the present embodiment is preferably used for boiling treatment.

The package bag may have a shape having a bent portion (bent portion), such as a stand-up pouch. The package bag according to the present embodiment can maintain high adhesion even in a shape having a curved portion.

Second aspect

< laminate >

Fig. 7 is a schematic cross-sectional view of a laminate 700 according to the present embodiment. The laminate 700 includes a base material layer (base material) 1, a gas barrier layer 10, an adhesive layer (adhesive layer) 2, and a sealant layer (heat seal layer) 3.

The base material layer 1 is an unstretched film made of polyethylene. This can suppress shrinkage or curling of the laminate 700 during processing, and stabilize the operability of the bag making, filling, and sealing steps. The haze value of the unstretched film is preferably 45% or less, more preferably 30% or less. The haze value of the present disclosure is defined as a value measured based on JIS K7105. The unstretched film may be produced by a method described later, or may be obtained from a film in circulation.

The base material layer 1 may also have an image formed on its surface. When an image is formed on the first surface 1a on the side where the gas barrier layer 10 is formed, it is preferable because deterioration with time due to contact with the external atmosphere can be prevented. The image to be formed is not particularly limited, and may be a character, a pattern, a symbol, a combination thereof, or the like.

The image formation on the substrate layer is preferably performed using an ink of biomass origin. Thus, a packaging material with less environmental load can be produced using the laminate 700. The image forming method is not particularly limited, and various printing methods known in the related art such as gravure printing method, offset printing method, and flexography method can be used. Among them, the flexible printing method is preferable from the viewpoint of environmental load.

As the polyethylene contained in the base material layer as a main component, high Density Polyethylene (HDPE), medium Density Polyethylene (MDPE), low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE), and ultra low density polyethylene (VLDPE) can be used.

As the high-density polyethylene, a density of 0.945g/cm may be used ³ The polyethylene above. As medium density polyethylene, a density of 0.925g/cm can be used ³ Above and below 0.945g/cm ³ Is a polyethylene of (a). As the low-density polyethylene, a polyethylene having a density of 0.900g/cm can be used ³ The above and below 0.925g/cm ³ Is a polyethylene of (a). As the linear low-density polyethylene, a polyethylene having a density of 0.900g/cm can be used ³ The above and below 0.925g/cm ³ Is a polyethylene of (a). As the ultra-low density polyethylene, a density of less than 0.900g/cm can be used ³ Is a polyethylene of (a). Among them, high-density polyethylene is preferable from the viewpoints of printability, strength and heat resistance.

The polyethylenes having different densities or branches as described above can be obtained by appropriately selecting the polymerization method. For example, preference is given to: the polymerization catalyst may be a multi-site catalyst such as a Ziegler-Natta catalyst or a single-site catalyst such as a metallocene catalyst, and may be carried out in one stage or two or more stages by any one of gas-phase polymerization, slurry polymerization, solution polymerization, and high-pressure ion polymerization.

The single-site catalyst is a catalyst capable of forming a uniform active species, and is usually produced by bringing a metallocene-based transition metal compound or a non-metallocene-based transition metal compound into contact with an activating co-catalyst. Compared with a multi-site catalyst, a single-site catalyst is preferable because the active site structure is uniform, and a polymer having a high molecular weight and a high uniformity structure can be polymerized. As single-site catalysts, particular preference is given to using metallocene catalysts. The metallocene catalyst is a catalyst comprising a group IV transition metal compound of the periodic table containing a ligand having a cyclopentadienyl skeleton, an auxiliary catalyst, an organic metal compound if necessary, and each catalyst component of a carrier.

In the above-mentioned transition metal compound of group IV of the periodic Table containing a ligand having a cyclopentadienyl skeleton, the cyclopentadienyl skeleton refers to a cyclopentdienyl group, a substituted cyclopentadienyl group or the like. The substituted cyclopentadienyl group is a group having at least one substituent selected from a hydrocarbon group having 1 to 30 carbon atoms, a silyl group-substituted alkyl group, a silyl group-substituted aryl group, a cyano group, a cyanoalkyl group, a cyanoaryl group, a halogen group, a haloalkyl group, a halosilyl group, and the like. The substituent of the substituted cyclopentadienyl group may have 2 or more substituents, and may be bonded to each other to form a ring, forming an indenyl ring, a fluorenyl ring, an azulenyl ring, a hydride thereof, or the like. The rings formed by bonding substituents to each other may further have substituents to each other.

Among the transition metal compounds of group IV of the periodic Table containing ligands having a cyclopentadienyl skeleton, zirconium, titanium, hafnium and the like are exemplified as the transition metal, and zirconium and hafnium are particularly preferable. In the transition metal compound, 2 ligands having a cyclopentadiene skeleton are usually used as the ligands, and each ligand having a cyclopentadiene skeleton is preferably bonded to each other through a crosslinking group. Examples of the crosslinking group include a substituted silylene group such as an alkylene group having 1 to 4 carbon atoms, a silylene group, a dialkylsilylene group, or a diarylsilene group, a substituted germylene group such as a dialkylgermylene group or a diarylmethylenegermylene group, and the like. Preferably a substituted silylene group. The above-mentioned transition metal compound of group IV of the periodic Table containing a ligand having a cyclopentadienyl skeleton may contain one or a mixture of two or more kinds as a catalyst component.

The auxiliary catalyst is a substance which can make the transition metal compound of group IV of the periodic table effective as a polymerization catalyst or can equalize ionic charges in a state of having been catalytically activated. Examples of the auxiliary catalyst include benzene-soluble aluminoxane of an organoaluminum oxy-compound or benzene-insoluble organoaluminum oxy-compound, ion-exchange layered silicate, boron compound, ionic compound composed of active hydrogen group-containing or active hydrogen group-free cation and noncoordinating anion, lanthanoid salt such as lanthanum oxide, tin oxide, fluorine group-containing phenoxy compound, and the like.

The transition metal compound of group IV of the periodic Table containing a ligand having a cyclopentadienyl skeleton may also be used as supported on an inorganic or organic compound. The support is preferably a porous oxide of an inorganic or organic compound, and examples thereof include montmorillonite-based plasma-exchanged layered silicate and SiO ₂ 、Al ₂ O ₃ 、MgO、ZrO ₂ 、TiO ₂ 、B ₂ O ₃ 、CaO、ZnO、BaO、ThO ₂ And mixtures thereof. As the organometallic compound used as needed, an organoaluminum compound, an organomagnesium compound, an organozinc compound, and the like can be exemplified. Among them, organoaluminum is preferably used.

Copolymers of ethylene with other monomers may also be used within a range that does not impair the properties of the present disclosure. The ethylene copolymer may be a copolymer of ethylene and an alpha-olefin having 3 to 20 carbon atoms. Examples of the α -olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-eicosene, 3-methyl-1-butene, 4-methyl-1-pentene, and 6-methyl-1-heptene. Further, the copolymer may be a copolymer with vinyl acetate, acrylic ester, or the like, as long as the object of the present disclosure is not impaired.

In the present disclosure, as a raw material for obtaining the above-described high-density polyethylene or the like, biomass-derived ethylene may also be used instead of ethylene obtained from fossil fuel. Since such biomass-derived polyethylene is a carbon-neutral material, it can be produced into a packaging material with less environmental load. Such biomass-derived polyethylene can be produced, for example, by the method described in Japanese patent application laid-open No. 2013-177531. Further, commercially available biomass-derived polyethylene (e.g., green PE commercially available from Braskem corporation, etc.) may be used.

Polyethylene recycled by mechanical recycling may also be used in the base material layer 1. Here, mechanical recycling generally refers to the following method: the recovered polyethylene film or the like is crushed and alkali-washed to remove dirt and foreign matter on the film surface, and then dried at a high temperature under reduced pressure for a certain period of time to diffuse and purify the contaminants remaining in the film, and the dirt of the film formed of polyethylene is removed to become polyethylene again.

The base material layer 1 may contain additives within a range that does not impair the characteristics of the present disclosure. Examples of the additives include a crosslinking agent, an antioxidant, an anti-blocking agent, a lubricant (slip agent), an ultraviolet absorber, a light stabilizer, a filler, a reinforcing agent, an antistatic agent, a pigment, and a modifying resin.

The thickness of the base material layer 1 is preferably 10 μm or more and 50 μm or less, more preferably 12 μm or more and 35 μm or less. By setting the thickness of the base material layer 1 to 10 μm or more, the strength of the laminate 700 can be improved. In addition, by setting the thickness of the base material layer 1 to 50 μm or less, the processing suitability of the laminate 700 can be improved.

The base material layer 1 can be produced by forming a film of polyethylene by a T-die method, an inflation method, or the like.

When the substrate layer 1 is produced by the T-die method, the Melt Flow Rate (MFR) of the polyethylene is preferably 3g/10 min or more and 20g/10 min or less. When the MFR is 3g/10 minutes or more, the processing suitability of the laminate 700 can be improved. In addition, when the MFR is 20g/10 min or less, breakage of the substrate layer to be produced can be prevented.

When the base material layer 1 is produced by the inflation method, the polyethylene preferably has an MFR of 0.5g/10 min or more and 5g/10 min or less. When the MFR is 0.5g/10 minutes or more, the processing suitability of the laminate 700 can be improved. In addition, the MFR is set to 5g/10 min or less, whereby the film forming property can be improved.

The substrate layer 1 is preferably subjected to surface treatment. The surface treatment method is not particularly limited, and examples thereof include corona discharge treatment, ozone treatment, low-temperature plasma treatment using oxygen and/or nitrogen, physical treatment such as arc discharge treatment, and chemical treatment such as oxidation treatment using a chemical agent.

When the laminate includes a gas barrier layer as in the present embodiment, an anchor coat layer (primer layer) may be formed on the first surface 1a on which the gas barrier layer is formed using a known anchor paint. This can improve the adhesion of the gas barrier layer formed of the metal oxide. Examples of the anchor coating agent include polyester polyurethane resin and polyether polyurethane resin. From the viewpoints of heat resistance and interlayer adhesion strength, polyester polyurethane resins are preferred.

The gas barrier layer 10 is provided on the first surface 1a side of the base material layer 1 directly or via another layer, and imparts oxygen barrier property or water vapor barrier property to the laminate 700.

Examples of the gas barrier layer include vapor deposition layers formed of metal oxides such as aluminum oxide, silicon oxide, magnesium oxide, and tin oxide. From the viewpoint of transparency and barrier properties, the metal oxide may be selected from aluminum oxide, silicon oxide, and magnesium oxide. Further, in view of printing suitability and cost, it may be selected from alumina and silica. Further, from the viewpoint of excellent tensile ductility during processing, it is more preferable to form a layer using silicon oxide. By using a vapor deposition layer formed of a metal oxide for the gas barrier layer, high barrier properties can be obtained with an extremely thin layer in a range that does not affect the recyclability of the gas barrier laminate.

The O/Al ratio when alumina is selected as the vapor deposition layer is preferably 1.4 or more. When the O/Al ratio is 1.4 or more, the content of unbound bonds of aluminum atoms is easily suppressed to obtain good transparency. The O/Al ratio is preferably 1.7 or less. When the O/Al ratio is 1.7 or less, the crystallinity of AlO can be prevented from being improved, and the vapor deposition layer becomes excessively hard, whereby good tensile properties can be obtained. In the packaging bag using the laminate 700, shrinkage may occur in the heat base layer 1 during the boiling treatment, but when the O/Al ratio of the gas barrier layer 10 is 1.7 or less, the shrinkage is easily followed, and the reduction in barrier properties due to occurrence of cracks or the like in the gas barrier layer 10 can be suppressed. From the viewpoint of obtaining these effects more sufficiently, the O/Al ratio of the deposition layer to be the gas barrier layer 10 is preferably 1.4 or more and 1.7 or less, more preferably 1.5 or more and 1.55 or less.

The O/Si ratio when silicon oxide is selected as the vapor deposition layer is preferably 1.7 or more. When the O/Si ratio is 1.7 or more, the content of unbound bonds of silicon atoms is easily suppressed, and good transparency is obtained. The O/Si ratio is preferably 2.0 or less. When the O/Si ratio is 2.0 or less, the crystallinity of SiO is prevented from being improved, and the vapor deposition layer is prevented from becoming excessively hard, whereby good tensile properties can be obtained. In addition, when the O/Si ratio of the gas barrier layer 10 is 2.0 or less, the shrinkage is easily followed, and the decrease in barrier property can be suppressed. From the viewpoint of obtaining these effects more sufficiently, the O/Si ratio of the deposition layer to be the gas barrier layer 10 is preferably 1.75 or more and 1.9 or less, more preferably 1.8 or more and 1.85 or less.

The thickness of the deposition layer formed of alumina is preferably 5nm to 30 nm. When the film thickness is 5nm or more, sufficient gas barrier properties can be obtained. When the film thickness is 30nm or less, occurrence of cracks due to deformation of the thin film due to internal stress can be suppressed, and reduction in gas barrier properties can be suppressed. In addition, when the film thickness exceeds 30nm, the cost tends to increase due to an increase in the amount of material used, a long film formation time, and the like, and therefore, it is not preferable from an economical point of view. From the same viewpoint as described above, the thickness of the deposition layer is more preferably 7nm to 15 nm.

The thickness of the deposition layer formed of silicon oxide is preferably 10nm to 50 nm. When the film thickness is 10nm or more, sufficient gas barrier properties can be obtained. When the film thickness is 50nm or less, occurrence of cracks due to deformation of the thin film due to internal stress can be suppressed, and reduction in gas barrier properties can be suppressed. In addition, when the film thickness exceeds 50nm, the cost tends to increase due to an increase in the amount of material used, a long film formation time, and the like, and therefore, it is not preferable from an economical point of view. From the same viewpoint as described above, the thickness of the deposition layer is more preferably 20nm to 40 nm.

The vapor deposition layer can be formed by vacuum deposition, for example. The vacuum film formation may be performed by physical vapor deposition or chemical vapor deposition. Examples of the physical vapor deposition method include, but are not limited to, a vacuum deposition method, a sputtering method, and an ion plating method. Examples of the chemical vapor deposition method include a thermal CVD method, a plasma CVD method, and a photo CVD method, but are not limited thereto.

Among the above vacuum film forming methods, a resistance heating type vacuum vapor deposition method, an EB (Electron Beam) heating type vacuum vapor deposition method, an induction heating type vacuum vapor deposition method, a sputtering method, a reactive sputtering method, a dual magnetron sputtering method, a plasma chemical vapor deposition method (PECVD method), or the like is particularly preferably used. However, in view of productivity, the vacuum vapor deposition method is currently most excellent. As the heating means of the vacuum vapor deposition method, any one of an electron beam heating system, a resistance heating system, and an induction heating system is preferably used.

The image may also be formed on the gas barrier layer when forming the image.

The adhesive layer 2 is a layer containing at least 1 adhesive, and is provided between the gas barrier layer 10 and the sealant layer 3 to join the two layers. Any adhesive such as one-component curing type or two-component curing type urethane type adhesive may be used in the adhesive layer 2. These adhesives may contain a lamellar inorganic compound for the purpose of further improving barrier properties.

The thickness of the adhesive layer 2 is preferably 0.5 μm or more and 6 μm or less, more preferably 0.8 μm or more and 5 μm or less, still more preferably 1 μm or more and 4.5 μm or less. By setting the thickness of the adhesive layer 2 to 0.5 μm or more, the adhesiveness of the adhesive layer 2 can be improved. By setting the thickness of the adhesive layer 2 to 6 μm or less, the workability of the laminate 700 can be improved.

The adhesive layer 2 can be formed by a known various methods such as a direct gravure roll coating method, a contact coating method, a reverse roll coating method, an ink fountain roll method, and a transfer roll coating method.

The sealant layer 3 is made of polyethylene, and is bonded by hot melt adhesion (heat sealing) when a packaging material such as a self-standing pouch is formed using the laminate 700.

The polyethylene constituting the sealant layer 3 is preferably selected from the group consisting of Low Density Polyethylene (LDPE), linear Low Density Polyethylene (LLDPE) and ultra low density polyethylene (VLDPE) from the viewpoint of heat sealability. The polyethylene of the base material layer 1 and the polyethylene of the sealant layer 3 may be the same or different. In addition, from the viewpoint of environmental load, biomass-derived polyethylene or recycled polyethylene is preferably used in the sealant layer.

In the sealant layer 3, a copolymer of ethylene and other monomers may be used within a range that does not impair the characteristics of the laminate 700.

The sealant layer 3 may be a single layer or may have a multilayer structure. When having a multilayer structure, the laminate may include a layer including at least one of medium-density polyethylene and high-density polyethylene.

The sealant layer 3 may be made of, for example, 3 layers including at least one of low density polyethylene, linear low density polyethylene, and ultra low density polyethylene, or at least one of medium density polyethylene and high density polyethylene, or at least one of low density polyethylene, linear low density polyethylene, and ultra low density polyethylene. By adopting such a structure, the bag making suitability and strength of the laminate 700 can be further improved while maintaining heat sealability.

The thickness of the sealant layer 3 may be appropriately changed according to the weight of the content filled in the produced packaging material, and the like. For example, in the case of manufacturing a package bag filled with 1g or more and 200g or less of the content, the thickness of the sealant layer 3 is preferably 20 μm or more and 60 μm or less. By setting the thickness to 20 μm or more, leakage of the filled content due to breakage of the sealant layer 3 can be prevented. By setting the thickness to 60 μm or less, the processing suitability of the laminate 700 can be improved.

As another example, in the case of manufacturing a self-standing pouch filled with contents of 50g or more and 2000g or less, the thickness of the sealant layer 3 is preferably 50 μm or more and 200 μm or less. By setting the thickness to 50 μm or more, leakage of the filled content due to breakage of the sealant layer 3 can be prevented. In addition, by setting the thickness to 200 μm or less, the processing suitability of the laminate 700 can be improved.

The laminate 700 of the present embodiment configured as described above is composed of polyethylene through the base material layer 1 and the sealant layer 3, and the proportion of polyethylene in the laminate 700 is 90 mass% or more. Thus, the laminate 700 has high recyclability.

The proportion (%) of polyethylene in the laminate 700 can be calculated by the following formula (1).

(mass of base material layer 1+mass of sealant layer 3)/mass of laminate as a whole×100 (1)

< packaging bag and self-standing bag >

When the sealant layers 3 in the peripheral portion are bonded by heat sealing with the filled portion of the content left in a state where 1 laminate 700 is folded with the sealant layers 3 facing each other or 2 laminates 700 are stacked with the sealant layers 3 facing each other, a package bag formed of the laminate 700 can be formed.

By performing the above-described bonding while sandwiching the folded base film, the laminate 700 can be used to form the self-standing pouch 900 shown in fig. 8.

The above-mentioned packaging bag or stand-alone pouch can contain various contents of solid, liquid, and gas.

The present inventors have found that a self-standing pouch using a laminate described in patent document 2 including a stretched high-density polyethylene film layer may be prone to bag breakage due to impact during falling. This phenomenon is particularly easy to occur when the contents are filled and sealed with a liquid having fluidity (including the case of containing a solid substance).

The present inventors have studied and found that, in a self-standing pouch which has been broken, a substrate layer breaks along a molecular chain. It is considered that the reason why the crystalline molecular chains are oriented in a certain direction in the stretched high-density polyethylene film as the base material layer is great. Further, it is also found that the crystalline molecular chains are aligned not only in the planar direction but also in the thickness direction, and thus delamination is likely to occur.

The details will be shown later in examples, but the present inventors succeeded in improving impact resistance while maintaining high recyclability by using an unstretched film in the base material layer. The orientation of the crystalline molecular chains in the unstretched film in both the plane direction and the thickness direction is not uniform in a certain direction. As a result, even when the impact is applied, breakage in one direction is difficult, and the adhesion strength between the layers can be preferably maintained.

In the present disclosure, an unstretched polyethylene film means a film which has not been subjected to stretching treatment, and means a polyethylene film in which spherical crystals (spherulites) of 10 to 100 μm degree composed of randomly-folded polyethylene molecular chains are changed to a structure connected by amorphous molecules. These structures can be confirmed by observation with a Scanning Electron Microscope (SEM) or observation with an X-ray diffraction method.

A second embodiment of the present disclosure is described with reference to fig. 9. In the following description, the same components as those already described are denoted by the same reference numerals, and the repetitive description thereof will be omitted.

Fig. 9 shows a laminate 800 according to the present embodiment. The laminate is provided with an adhesive layer 2A instead of the adhesive layer 2. The adhesive layer 2A is formed of a barrier adhesive (gas barrier adhesive) that can exhibit gas barrier properties after curing.

The gas barrier adhesive used for the adhesive layer 2A includes an epoxy adhesive, a polyester-polyurethane adhesive, and the like. Specific examples include "Maxive" manufactured by Mitsubishi GAS chemical corporation, and "Paslim" manufactured by DIC corporation.

The laminate 800 according to the present embodiment exhibits the same effects as the laminate 700 according to the first embodiment. Further, by providing the adhesive layer 2A, the adhesive layer 2A protects the gas barrier layer and exhibits barrier properties independently of the gas barrier layer. Therefore, even if physical impacts such as friction generated during the production of the laminate, thermal shock due to heat sealing during the production of the self-supporting bag or filling of the content, and falling impact of the packaging bag filled with the content during the circulation are received, the occurrence of cracks in the gas barrier layer can be suppressed, and even if cracks are generated, the decrease in barrier properties can be suppressed to the minimum.

In either of the first and second embodiments, the gas barrier layer may further include a gas barrier coating layer (cap coating layer). The gas barrier coating layer may be provided between the vapor deposition layer and the adhesive layer. The gas barrier coating layer protects the vapor deposition layer and exhibits barrier properties independently of the vapor deposition layer.

The gas barrier coating layer can be formed using an aqueous solution containing at least 1 selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide, a silane coupling agent, and a hydrolysate thereof, or a composition for forming a gas barrier coating layer (hereinafter also referred to as a coating agent) containing a water/alcohol mixed solution as a main component.

The coating agent preferably contains at least a silane coupling agent or a hydrolysate thereof, more preferably contains at least 1 selected from the group consisting of a hydroxyl group-containing polymer compound, a metal alkoxide and a hydrolysate thereof, and a silane coupling agent or a hydrolysate thereof, and even more preferably contains a hydroxyl group-containing polymer compound or a hydrolysate thereof, a metal alkoxide or a hydrolysate thereof, and a silane coupling agent or a hydrolysate thereof, from the viewpoint of maintaining gas barrier properties after hot water treatment such as high temperature retort treatment more sufficiently. The coating agent can be prepared, for example, as follows: the metal alkoxide and the silane coupling agent are directly mixed or mixed with a solution in which a hydroxyl group-containing polymer compound, which is a water-soluble polymer, is dissolved in an aqueous solvent (water or water/alcohol mixture), or a product obtained by subjecting the metal alkoxide and the silane coupling agent to a treatment such as hydrolysis in advance.

Each component contained in the coating agent is described in detail. Examples of the hydroxyl group-containing polymer compound used in the coating agent include polyvinyl alcohol (PVA), polyvinylpyrrolidone, starch, methylcellulose, carboxymethylcellulose, and sodium alginate. When PVA is used as the coating agent, the gas barrier property of the gas barrier coating layer is particularly excellent, and thus it is preferable.

The gas barrier coating layer is preferably formed of a composition containing at least 1 selected from the group consisting of metal alkoxides represented by the following general formula (I) and hydrolysates thereof, from the viewpoint of obtaining excellent gas barrier properties.

M(OR ³ ) _m (R ⁴ ) _n-m (I)

In the general formula (I), R is ³ R is R ⁴ Each independently represents a 1-valent organic group having 1 to 8 carbon atoms, and is preferably an alkyl group such as a methyl group or an ethyl group. M represents Si, ti,N-valent metal atoms such as Al and Zr. m is an integer of 1 to n, when R ³ Or R is ⁴ When there are plural, R ³ Each other or R ⁴ May be the same as or different from each other.

Specific examples of the metal alkoxide include tetraethoxysilane [ Si (OC) ₂ H ₅ ) ₄ ]Triisopropoxyaluminum [ Al (O-2' -C) ₃ H ₇ ) ₃ ]Etc. Tetraethoxysilane and triisopropoxyaluminum are preferred because they are stable in an aqueous solvent after hydrolysis.

The silane coupling agent may be a compound represented by the following general formula (II).

Si(OR ¹¹ ) _p (R ¹² ) _3-p R ¹³ (II)

In the general formula (II), R is ¹¹ Represents an alkyl group such as a methyl group or an ethyl group. R is R ¹² Represents a 1-valent organic group such as an alkyl group, an aralkyl group, an aryl group, an alkenyl group, an alkyl group substituted with an acryloyloxy group, or an alkyl group substituted with a methacryloyloxy group. R is R ¹³ Represents a 1-valent organic functional group. p represents an integer of 1 to 3. R is R ¹¹ Or R is ¹² When there are plural, R ¹¹ Each other or R ¹² May be the same as or different from each other. As R ¹³ Examples of the 1-valent organic functional group include glycidoxy, epoxy, mercapto, hydroxyl, amino, alkyl substituted with halogen atom, and 1-valent organic functional group containing isocyanate group.

Specific examples of the silane coupling agent include silane coupling agents such as vinyltrimethoxysilane, γ -chloropropylmethyldimethoxysilane, γ -chloropropyltrimethoxysilane, glycidoxypropyl trimethoxysilane, γ -methacryloxypropyl trimethoxysilane, and γ -methacryloxypropyl methyldimethoxysilane.

The silane coupling agent may be a polymer obtained by polymerizing a compound represented by the general formula (II). The polymer is preferably a trimer, more preferably 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate. This is a polycondensate of 3-isocyanatoalkylalkoxysilane. The 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate is known to be chemically inactive at the isocyanato, but the reactivity is ensured by the polarity of the allophanate moiety. In general, 3-isocyanate alkylalkoxysilane is added to an adhesive or the like as in the case of the 3-isocyanate alkylalkoxysilane, and is known as an adhesion improver. Thus, by adding 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate to the hydroxyl group-containing polymer compound, the water resistance of the gas barrier coating layer can be improved by hydrogen bonding. The 3-isocyanate alkylalkoxysilane has high reactivity and low liquid stability, but the urethane part of 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate is insoluble in water due to its polarity, but is easily dispersed in an aqueous solution, and can stably maintain the liquid viscosity. In addition, 3-isocyanatoalkylalkoxysilane and 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate are equivalent for water resistance.

The 1,3, 5-tris (3-trialkoxysilylalkyl) isocyanurate is produced by thermal condensation of 3-isocyanate propyl alkoxysilane, and may contain 3-isocyanate propyl alkoxysilane as a raw material, and is not particularly problematic. More preferably 1,3, 5-tris (3-trialkoxysilylpropyl) isocyanurate, and still more preferably 1,3, 5-tris (3-trimethoxysilylpropyl) isocyanurate. Since the hydrolysis rate of the methoxy group is high and the hydrolysis rate is relatively inexpensive for those containing a propyl group, 1,3, 5-tris (3-trimethoxysilylpropyl) isocyanurate is practically advantageous.

The coating agent may be added with an isocyanate compound, or a known additive such as a dispersant, a stabilizer, a viscosity modifier, or a colorant, as necessary, within a range that does not impair the gas barrier property.

The thickness of the gas barrier coating layer is preferably 50 to 1000nm, more preferably 100 to 500nm. When the thickness of the gas barrier coating layer is 50nm or more, a more sufficient gas barrier property tends to be obtained, and when it is 1000nm or less, a sufficient flexibility tends to be maintained.

The coating liquid for forming the gas barrier coating layer can be applied by, for example, dip coating, roll coating, gravure coating, reverse gravure coating, air knife coating, comma roll coating, die coating, screen printing, spray coating, gravure offset printing, or the like. The coating film obtained by applying the coating liquid may be dried by, for example, a hot air drying method, a hot roll drying method, a high frequency irradiation method, an infrared irradiation method, a UV irradiation method, or a combination thereof.

The temperature at which the coating film is dried may be, for example, 50 to 150 ℃, and preferably 70 to 100 ℃. When the temperature at the time of drying is within the above range, the occurrence of cracks in the inorganic oxide layer (vapor deposition layer) or the gas barrier coating layer can be further suppressed, and excellent barrier properties can be exhibited.

The gas barrier coating layer may be formed using a coating agent containing a polyvinyl alcohol resin and a silane compound. The coating agent may be optionally added with an acid catalyst, a base catalyst, a photopolymerization initiator, and the like.

The polyvinyl alcohol resin may be any of the above resins. The silane compound may be a silane coupling agent, polysilazane, siloxane, or the like, and specifically may be tetramethoxysilane, tetraethoxysilane, glycidoxypropyl trimethoxysilane, acryloxypropyl trimethoxysilane, hexamethyldisilazane, or the like.

Examples

The present disclosure will be further described in detail with reference to the following examples, but the present disclosure is not limited to these examples.

[ preparation of composition for Forming primer layer ]

The acrylic polyol and toluene diisocyanate were mixed so that the number of OH groups of the acrylic polyol and the number of NCO groups of the toluene diisocyanate became equal, and diluted with ethyl acetate so that the total solid content (total amount of acrylic polyol and toluene diisocyanate) became 5 mass%. To the diluted mixed solution, 5 parts by mass of β - (3, 4-epoxycyclohexyl) trimethoxysilane was further added to 100 parts by mass of the total amount of the acrylic polyol and toluene diisocyanate, and these were mixed to prepare an undercoat layer-forming composition (anchor paint) AC-1. In tables 2 and 3, the primer layer is described as "AC layer".

[ preparation of adhesive for Forming adhesive layer ]

(adhesive A)

LX500/KR500 (trade name) manufactured by DIC Graphics corporation as the urethane-based adhesive was used as the adhesive A.

(adhesive B)

In the mass ratio of 1:1 to 23 parts by mass of a solvent containing ethyl acetate and methanol, 16 parts by mass of Maxive C93T manufactured by mitsubishi GAS chemical company and 5 parts by mass of Maxive M-100 manufactured by mitsubishi GAS chemical company were mixed to prepare an adhesive B as an epoxy adhesive.

[ preparation of composition for Forming gas Barrier coating layer ]

(OC-1)

The following solutions were prepared to prepare a coating liquid for forming a gas barrier coating layer. As the hydroxyl group-containing polymer compound, polyvinyl alcohol resins (PVA, trade name: selvol-325 (degree of saponification 98 to 99%, degree of polymerization 1700), sekisui Specialty Chemicals America, manufactured by LLC. Co., ltd.) were used. Mixing the polyvinyl alcohol resin and water, heating to 95 ℃, and dissolving the polyvinyl alcohol resin in the water. After cooling the mixture to room temperature, the mixture was diluted with water and isopropyl alcohol (mass ratio: 1:1) so that the final solid content became 5 mass%, to prepare a gas barrier coating layer-forming composition OC-1. In tables 2 and 3, the gas barrier coating layer is referred to as "OC layer".

(OC-2)

An aqueous solution in which a polyvinyl alcohol resin (PVA, trade name: poval PVA-105, polyvinyl alcohol having a degree of saponification of 98 to 99% and a degree of polymerization of 500 manufactured by Kuraray Co., ltd.) was dissolved was prepared; tetraethoxysilane (TEOS) and gamma-glycidoxypropyl trimethoxysilane (GPTMS, trade name: KBM-403, manufactured by Xinyue chemical Co., ltd.) were hydrolyzed with 0.02mol/L hydrochloric acid, respectively. The aqueous solution comprises PVA in mass ratio before hydrolysis: TEOS: GPTMS reaches 40:50: 10. Isopropanol as a diluting solvent is added to the aqueous solution, and water is added in a mass ratio of the solvent components: isopropanol reaches 90:10, and a gas barrier coating layer-forming composition OC-2 having a solid content concentration of 5 mass% was prepared.

Examples 1 to 1

An A4-size unstretched high-density polyethylene film (unstretched HDPE having a density of 0.956 g/cm) ³ A thickness of 32 μm), the adhesive a was coated with a wire rod, and dried at 60 ℃ to form an adhesive layer having a thickness of 3 μm. Next, an unstretched film (unstretched LLDPE-1, density 0.920 g/cm) of 60 μm thickness made of a linear low-density polyethylene resin was stuck as a sealant layer ³ Trade name, manufactured by TOHCELLO corporation, three well chemistry: TUX-MCS). Thereafter, aging was performed at 40℃for 4 days. Thus, a laminate having a laminate structure of a base material layer, an adhesive layer, and a sealant layer was obtained.

Examples 1 to 2

Except that a corona-treated A4-size unstretched medium-density polyethylene film (unstretched HDPE, density of 0.940 g/cm) ³ Manufactured by tamopo corporation, trade name: UB-3, thickness of 40 μm), a laminate having a laminate structure of a base material layer, an adhesive layer, and a sealant layer was obtained in the same manner as in example 1-1.

Examples 1 to 3

Except that an unstretched film (unstretched LLDPE-2, density of 0.920 g/cm) having a thickness of 60 μm formed of a linear low-density polyethylene resin was used as the sealant layer ³ Manufactured by tamopo corporation, trade name: UB-106), a laminate having a laminate structure of a base material layer, an adhesive layer, and a sealant layer was obtained in the same manner as in example 1-1.

Comparative examples 1 to 1

Except that a corona-treated A4-sized stretched high-density polyethylene film (stretched HDPE-1, density of 0.960 g/cm) was used as the base layer ³ Manufactured by tokyo INK corporation, trade name: SMUQ, thickness 25 μm) was obtained in the same manner as in example 1-1, except that a substrate layer/adhesive was provided Laminate of laminate structure of adhesive layer/sealant layer.

Comparative examples 1 to 2

Except that a corona-treated A4-sized stretched high-density polyethylene film (stretched HDPE-2, density of 0.960 g/cm) was used as the base layer ³ Trade name, manufactured by Futamura Chemical company: PE3KH, thickness of 25 μm), a laminate having a laminate structure of a base layer, an adhesive layer and a sealant layer was obtained in the same manner as in example 1-1.

Comparative examples 1 to 3

Except that a corona-treated A4-size unstretched low-density polyethylene film (unstretched LLDPE-1, density of 0.920 g/cm) was used as the base layer ³ Trade name, manufactured by TOHCELLO corporation, three well chemistry: TUX-MCS, thickness 40 μm), and a laminate having a laminate structure of a base material layer, an adhesive layer, and a sealant layer was obtained in the same manner as in example 1-1.

Examples 1 to 4

A laminate having a laminate structure of a base layer, an adhesive layer, and a sealant layer was obtained in the same manner as in example 1-1, except that an adhesive B was used instead of the adhesive a.

Examples 1 to 5

Except that the film was formed of A4-size unstretched high-density polyethylene film (unstretched HDPE, density 0.956 g/cm) ³ A thickness of 32 μm), the primer layer-forming composition AC-1 was coated with a wire rod, dried and cured at 60℃to give a urethane acrylate resin having a coating weight of 0.1g/m ² Is a primer layer of (a).

A transparent vapor deposition layer (silicon oxide vapor deposition layer) of 30nm in thickness was formed on the undercoat layer by a vacuum vapor deposition apparatus using an electron beam heating system. As the silica vapor deposited film, a vapor deposited film having an O/Si ratio of 1.8 was formed by adjusting the vapor deposited material type.

The adhesive A was coated on the deposition layer with a wire rod, dried at 60℃to form an adhesive layer having a thickness of 3. Mu.m, and then a linear low density polyethylene resin (LLD) was applied as a sealant layerPE) into an unstretched film (unstretched LLDPE-1, having a density of 0.920 g/cm) having a thickness of 60. Mu.m ³ Trade name, manufactured by TOHCELLO corporation, three well chemistry: TUX-MCS). Thereafter, aging was performed at 40℃for 4 days. Thus, a laminate having a laminate structure of a base material layer/undercoat layer/vapor deposition layer/adhesive layer/sealant layer was obtained.

Examples 1 to 6

A laminate having a laminate structure of a base material layer, a primer layer, a vapor deposition layer, a gas barrier coating layer, an adhesive layer, and a sealant layer was obtained in the same manner as in examples 1 to 5, except that a gas barrier coating layer was formed on the vapor deposition layer in the following order. That is, the gas barrier coating layer forming composition OC-1 was coated on the undercoat layer with a wire rod, and dried at 60℃to form a gas barrier coating layer having a thickness of 0.3. Mu.m.

Examples 1 to 7

A laminate having a laminate structure of a base layer, an undercoat layer, a vapor deposition layer, a gas barrier coating layer, an adhesive layer, and a sealant layer was obtained in the same manner as in examples 1 to 6, except that the gas barrier coating layer-forming composition OC-2 was used in place of the gas barrier coating layer-forming composition OC-1.

Examples 1 to 8

A laminate having a laminate structure of a base layer, a primer layer, a vapor deposition layer, an adhesive layer, and a sealant layer was obtained in the same manner as in examples 1 to 5, except that an adhesive B was used instead of the adhesive a.

Examples 1 to 9

An A4-size unstretched high-density polyethylene film (unstretched HDPE having a density of 0.956 g/cm) ³ A thickness of 32 μm), a deposition layer of aluminum was formed with a thickness of 50nm by a vacuum deposition apparatus using an induction heating system.

The adhesive B was coated on the deposition layer with a wire rod, dried at 60℃to form an adhesive layer having a thickness of 3. Mu.m, and then an unstretched film (unstretched LLDPE-1, density of 0.920 g/cm) having a thickness of 60. Mu.m, which was a linear low density polyethylene resin (LLDPE) was adhered as a sealant layer ³ Trade name, manufactured by TOHCELLO corporation, three well chemistry: TUX-MCS). Thereafter, aging was performed at 40℃for 4 days. Thus, a laminate having a laminate structure of a base material layer/a vapor deposition layer/an adhesive layer/a sealant layer was obtained.

Examples 1 to 10

A laminate having a laminate structure of a base layer, an undercoat layer, a vapor deposition layer, an adhesive layer, and a sealant layer was obtained in the same manner as in examples 1 to 8, except that the vapor deposition layer was formed by the following method. That is, a transparent vapor-deposited layer (aluminum oxide vapor-deposited film) of aluminum oxide having a thickness of 15nm was formed on the undercoat layer by a vacuum vapor deposition apparatus using an electron beam heating system. As an alumina vapor-deposited film, a vapor-deposited film having an O/Al ratio of 1.5 was formed by adjusting the type of vapor-deposited material.

Comparative examples 1 to 4

Except that a corona-treated A4-sized stretched high-density polyethylene film (stretched HDPE-1, density of 0.960 g/cm) was used as the base layer ³ Manufactured by tokyo INK corporation, trade name: SMUQ, thickness of 25 μm)) was obtained in the same manner as in examples 1 to 7, except that a laminate having a laminate structure of a base material layer, a primer layer, a vapor deposition layer, a gas barrier coating layer, an adhesive layer, and a sealant layer was obtained.

Examples 1 to 11

Except that a printed layer was formed on a base layer in the following order, and an unstretched film (unstretched LLDPE-2, density 0.920 g/cm) having a thickness of 60 μm formed of a linear low-density polyethylene resin was used as a sealant layer ³ Manufactured by tamopo corporation, trade name: UB-106), a laminate having a laminate structure of a base layer, a print layer, an adhesive layer, and a sealant layer was obtained in the same manner as in example 1-1. That is, a pattern is printed on the base material layer by a printer, thereby forming a printed layer.

Examples 1 to 12

Except that a printed layer was formed on the gas barrier coating layer in the following order, and an unstretched film (unstretched LLDPE-1, density 0.920 g/cm) having a thickness of 60 μm formed of a linear low-density polyethylene resin was used as the sealant layer ³ Trade name, manufactured by TOHCELLO corporation, three well chemistry: TUX-MCS), and the real oneExamples 1 to 7 similarly obtained a laminate having a laminate structure of a base layer/undercoat layer/vapor deposition layer/gas barrier coating layer/print layer/adhesive layer/sealant layer. That is, a pattern is printed on the gas barrier coating layer by a printer to form a printed layer.

Examples 1 to 13

An A4-size unstretched high-density polyethylene film (unstretched HDPE having a density of 0.956 g/cm) ³ A thickness of 32 μm) was printed with a pattern using a printer to form a printed layer. Thereby, a first film with a printed layer was obtained.

An A4-size unstretched high-density polyethylene film (unstretched HDPE having a density of 0.956 g/cm) ³ The composition AC-1 for forming an undercoat layer was applied to a corona-treated surface having a thickness of 32 μm) by a filament bar, and dried and cured at 60℃to give a urethane acrylate resin having a coating weight of 0.1g/m ² Is a primer layer of (a).

A transparent vapor deposition layer (silicon oxide vapor deposition layer) of 30nm in thickness was formed on the undercoat layer by a vacuum vapor deposition apparatus using an electron beam heating system. As the silica vapor deposited film, a vapor deposited film having an O/Si ratio of 1.8 was formed by adjusting the vapor deposited material type.

The adhesive B was coated on the deposited layer with a wire rod, dried at 60℃to form an adhesive layer having a thickness of 3. Mu.m, and then an unstretched film (unstretched LLDPE-1 having a density of 0.920 g/cm) having a thickness of 60. Mu.m and formed of a linear low-density polyethylene resin was adhered as a sealant layer ³ Trade name, manufactured by TOHCELLO corporation, three well chemistry: TUX-MCS). Thereafter, aging was performed at 40℃for 4 days. Thereby obtaining a second film with a gas barrier layer.

The adhesive a was coated on the printed layer of the first film with the printed layer by a wire rod, dried at 60 ℃ to form an adhesive layer having a thickness of 3 μm, and then the second film with the gas barrier layer was adhered so that the resin layer was in contact with the adhesive layer, and aged at 40 ℃ for 4 days. Thus, a laminate having a laminate structure of a base material layer/a print layer/an adhesive layer/a resin layer/an undercoat layer/a vapor deposition layer/an adhesive layer/a sealant layer was obtained.

[ measurement of physical Properties ]

(Density)

The densities of the base material layer, the sealant layer, and the resin layer were determined based on JIS K7112:1999 assay method.

(degree of molecular orientation)

The molecular orientation degree of the base material layer and the sealant layer was measured using a molecular orientation meter (trade name: MOA-5012A, manufactured by prince measuring instruments Co., ltd.).

(Hot melt bonding temperature)

The heat-fusible bonding temperature of the base material layer and the sealant layer was set to be in accordance with JIS Z0238:1998, the heat sealing temperature of the layer to be measured. Specifically, 2 measurement object layers were stacked, and a heat seal portion was formed by heating under a pressure of 0.2MPa for 1 second using a heat seal tester, and the lowest temperature at which heat fusion bonding can be performed to form a heat seal portion that was not peeled off was set as the heat fusion bonding temperature. Table 1 to table 3 show the difference in the hot melt adhesion temperature between the base material layer and the sealant layer.

(oxygen Transmission Rate (OTR))

The oxygen permeability of the adhesive layer was measured by the following method. Adhesive a or adhesive B was coated with a wire rod on the corona treated surface of A4-size Polyethylene (PE) film (thickness 32 μm), and dried and cured at 60 ℃ to form a coating film (adhesive layer) having a thickness of 3 μm. An unstretched film (trade name: TUX-MCS, manufactured by Sanchi chemical TOHCELLO Co., ltd.) having a thickness of 60 μm, which was formed of a linear low density polyethylene resin (LLDPE), was stuck to the coating film to obtain a laminate. The oxygen permeability of the obtained laminate was measured at a temperature of 30℃and a relative humidity of 70% (JIS K7126-2 (isobaric method)). The measurement was performed using an oxygen permeability measuring apparatus (trade name: OX-TRAN2/20, manufactured by MOCON Co.). The detection limit of the measuring device was 200cc/m ² Day atm, so that when the measured value is not less than the detection limit, the oxygen permeability of the adhesive layer>200cc/m ² ·day·atm。

[ evaluation of laminate ]

(adhesion Strength (lamination Strength))

The laminate was cut into a long strip having a width of 15mm, and the laminate was peeled off at a speed of 300 mm/min by a Tensilon Universal materials tester (manufactured by Kagaku Co., ltd.) to measure the lamination strength. The measurement was performed according to the peel adhesion strength test method under 180-degree peel (JIS K6854-2, ISO 8510-2).

(bag making suitability)

2 laminates were prepared. The 2 laminated layers were stacked so that the sealant layers faced each other, and heat sealing was performed under variable temperature conditions for 0.2MPa and 1 second using a heat sealer. The heat-sealed test piece was cut into a 15mm wide long strip shape according to JIS Z0238: the "heat seal Strength test of bags" described in 1998 was used for the heat seal Strength measurement. The heat seal strength was measured using a Tensilon Universal materials tester (manufactured by Kagaku Co., ltd.) at a stretching speed of 300 mm/min. By performing heat sealing under variable temperature conditions, a heat seal curve formed by the heat seal temperature and the heat seal strength is produced. In the heat seal curve, a temperature range from a temperature at which a heat seal strength of 10N/15mm or more is obtained to a temperature at which the seal portion is deformed in appearance by fusion by hot melt adhesion is taken as a bag making suitability temperature, and a temperature range of 10 ℃ or more is determined to be good in bag making suitability. In the evaluations of the suitability for bag making in tables 4 to 6, the case where the suitability for bag making temperature range was 10℃or higher was designated "A", and the case where the suitability for bag making temperature range was less than 10℃was designated "B".

(oxygen Transmission Rate (OTR))

The oxygen permeability (cc/m) of the laminate was measured under an ambient gas at 30℃and 70% RH according to JIS K7126-2 (isobaric method) using an oxygen permeability measuring device (trade name: OX-TRAN2/20, manufactured by MOCON Co., ltd.) ² Day atm). Since the detection limit of the measuring device is 200cc/m ² Day atm, therefore, when the measured value is not less than the detection limit, the oxygen permeability of the laminate under an ambient gas of 30℃and 70% RH is measured according to JIS K7126-1 (differential pressure method) using a differential pressure type gas permeation rate measuring device (trade name: GTR-100G, gas: oxygen, manufactured by YANACO Co., ltd.)(cc/m ² ·day·atm)。

(impact resistance (bag drop test))

2 samples were prepared by cutting the laminate into 150mm longitudinal by 138mm transverse pieces. 2 samples were stacked so that each sealant layer was inside, and 1 side of each longitudinal end and 2 sides of each lateral end were heat sealed by a heat sealer to form a 10mm wide sealed portion, thereby producing a bag with one side of each longitudinal end open. Then, 150g of water was filled from the opening of the bag. Thereafter, the opening was heat-sealed over a width of 10mm by a heat sealer to form a sealed portion, and the bag was sealed.

The sealed bag was dropped horizontally from a height of 50 cm. The number of falling times was 10 times, and the number of bags horizontally fallen was 5. After 10 horizontal drops, the presence or absence of broken bags was visually confirmed for each of the 5 bags. Impact resistance was evaluated according to the following evaluation criteria. Further, the laminate in which the bag was not produced and the suitability for bag production was "B", was not evaluated for impact resistance.

A: after 10 horizontal drops, no bag breakage was seen in all 5 bags.

B: after 10 horizontal drops, a broken bag was visible in more than 1 bag.

(printing suitability)

The laminate having the printed layer formed thereon was visually checked for the printed layer after printing, and the printing suitability was evaluated according to the following evaluation criteria.

A: no deviation of the pitch of the printed pattern was seen, and no relaxation and wrinkles of the film were seen after printing.

B: at least one of the case of a pitch deviation of the printed pattern and the case of relaxation and wrinkling of the film after printing can be seen.

(boiling test)

The laminate was cut into a size of 15cm×21cm, and 2 cut laminates were stacked with the sealant layers facing each other, and 3-sided pulse sealed in a bag shape. 200ml of tap water was filled as the content in the bag, and the remaining 1 side was pulse-sealed to prepare a 4-side sealed bag (packaging bag). The obtained bag was subjected to boiling treatment using a boiling treatment apparatus at 80℃for 30 minutes or at 95℃for 30 minutes. After boiling, the bag was opened, tap water was discarded, and the laminate strength and oxygen permeability (OTR) were measured in a sufficiently dry state by the same method as described above. Further, the laminate of examples 1-11 to 1-13 was observed for appearance of the bag after boiling, and whether or not there was interlayer peeling or floating of the film was visually confirmed, but no problem was found in any of the bags.

TABLE 4 Table 4

TABLE 5

TABLE 6

[ preparation of composition for Forming primer (anchor coating agent) ]

A primer layer-forming composition (anchor coat) AC-1 was prepared in the same manner as described above.

[ preparation of composition for Forming gas Barrier coating layer (coating agent) ]

The following solutions A, B and C were mixed in a mass ratio of 70/20/10, respectively, to prepare a composition (a primer) for forming a gas barrier coating layer. In table 7, the gas barrier coating layer is referred to as "OC layer".

And (3) solution A: in tetraethoxysilane (Si (OC) ₂ H ₅ ) ₄ ) To 17.9g and 10g of methanol, 72.1g of 0.1N hydrochloric acid was added, and the mixture was stirred for 30 minutes to hydrolyze the solid content, which was 5 mass% (SiO) ₂ Converted) hydrolysis solution

And (2) liquid B: 5% by mass water/methanol solution of polyvinyl alcohol (water: methanol mass ratio 95:5)

And C, liquid: 1,3, 5-tris (3-trialkoxysilylpropyl) isocyanurate was diluted with a water/isopropanol mixture (water: isopropanol mass ratio: 1:1) to a hydrolysis solution having a solid content of 5 mass%

[ production of substrate A ]

On a corona-treated surface of an unstretched polyethylene film (3 layers of HDPE/MDPE/HDPE) having a thickness of 25 μm on one surface thereof subjected to corona treatment, the composition for forming an undercoat layer was applied by a gravure coating method and dried, and an undercoat layer having a thickness of 0.1 μm was provided. Next, a transparent deposition layer (alumina deposition film) of 10nm thickness formed of alumina was formed by a vacuum deposition apparatus using an electron beam heating system. The O/Al ratio of the alumina vapor deposited film was 1.5 by adjusting the vapor deposition material type. The gas barrier coating layer-forming composition was applied to the vapor deposited layer by gravure coating and dried to form a gas barrier coating layer having a thickness of 0.3 μm and having a gas barrier function. From the above, the substrate a having the vapor deposition layer and the gas barrier coating layer formed of alumina was obtained.

[ production of substrate B ]

The composition for forming an undercoat layer was applied by gravure coating to the same unstretched polyethylene film as the substrate A, and dried to provide an undercoat layer having a thickness of 0.1. Mu.m. Then, a transparent vapor deposition layer (silicon oxide vapor deposition layer) of 30nm thickness formed of silicon oxide was formed by a vacuum vapor deposition apparatus using an electron beam heating system. The O/Si of the silicon dioxide vapor deposition film was 1.8 by adjusting the vapor deposition material species. From the above, a base material B having a vapor deposition layer formed of silica was obtained.

[ production of substrate C ]

A substrate C having a vapor deposition layer made of alumina and a gas barrier coating layer formed thereon was obtained in the same manner as the substrate a except that a uniaxially stretched polyethylene film (3 layers of HDPE/MDPE/HDPE) was used in which one surface of the polyethylene film having a thickness of 25 μm was subjected to corona treatment and was stretched only in the MD (machine direction) direction (the flow direction of the film formation).

[ production of substrate D ]

A substrate D on which a vapor deposition layer formed of silica was formed was obtained in the same order as that of the substrate B except that a biaxially stretched polyethylene film (3 layers of HDPE/MDPE/HDPE) was used in which one side of the polyethylene film having a thickness of 25 μm was subjected to corona treatment and was stretched in the MD direction and the TD direction (transverse direction) (transverse direction): direction orthogonal to the MD direction on the side).

Example 2-1

An unstretched polyethylene film (composed of 3 layers of HDPE/MDPE/HDPE) having a thickness of 25 μm and a non-stretched polyethylene film (composed of a single layer of LLDPE) having a thickness of 40 μm as a sealant layer, each of which had been subjected to a corona treatment on one side, were laminated by a dry lamination method using a urethane adhesive. Thus, a laminate of example 2-1 was obtained. Example 2-1 is an example without a gas barrier layer.

Examples 2 to 2

The same sealant layer as in example 2-1 was laminated on the gas barrier coating layer side of the base material a by a dry lamination method using a urethane adhesive. The laminate of example 2-2 was obtained as described above.

Examples 2 to 3

On the vapor deposition layer side of the base material B, the same sealant layer as in example 2-1 was laminated by a dry lamination method using a gas barrier adhesive. The gas barrier adhesive was used in a mass ratio of 1: 1A solvent containing ethyl acetate and methanol was mixed with 23 parts by mass of an epoxy adhesive containing 16 parts by mass of Maxive C93T manufactured by Mitsubishi GAS chemical corporation and 5 parts by mass of Maxive M-100 manufactured by Mitsubishi GAS chemical corporation. The thickness of the gas barrier adhesive was 3. Mu.m. The laminates of examples 2 to 3 were obtained from the above.

Comparative example 2-1

A biaxially stretched polyethylene film (3 layers of HDPE/MDPE/HDPE) having a thickness of 25 μm, which was subjected to corona treatment on one side, and an unstretched polyethylene film (single layer of LLDPE) having a thickness of 40 μm, which was used as a sealant layer, were laminated by a dry lamination method using a urethane adhesive. From the above, a laminate of comparative example 2-1 was obtained. Comparative example 2-1 does not have a gas barrier layer.

Comparative examples 2-2

The same sealant layer as in example 2-1 was laminated on the gas barrier coating layer side of the base material C by a dry lamination method using a urethane adhesive. From the above, a laminate of comparative example 2-2 was obtained.

Comparative examples 2 to 3

The same sealant layer as in example 2-1 was laminated on the vapor deposition layer side of the substrate D by a dry lamination method using the same gas barrier adhesive as in example 2-3. The thickness of the gas barrier adhesive was 3. Mu.m. From the above, laminate of comparative examples 2 to 3 was obtained.

[ evaluation ]

The laminates of the examples and comparative examples were evaluated as follows. The results are shown in table 7.

(recyclability)

The polyethylene content (mass%) in each laminate was calculated from the above formula (1). The following 2 grades are evaluated.

A (good): contains polyethylene in an amount of 90% by mass or more.

B (bad): the content of polyethylene is less than 90 mass%.

(impact resistance)

10 packaging bags of 100mm by 150mm, each having a peripheral portion heat-sealed, were produced using the laminate of each example. The package was filled with 200g of distilled water, sealed by heat sealing, and stored at 5℃for 1 day. After storage, each package was dropped 50 times from a height of 1.5m, and the number of packages in which breakage occurred was recorded.

(oxygen permeability: OTR)

The oxygen permeability was measured by the Mocon method at 30℃and 70% RH (relative humidity). In the examples, in addition to the measurement of the oxygen permeability of the laminate monomer, the oxygen permeability of the packaging bag in which no bag breakage occurred in the impact resistance evaluation was also measured.

(Water vapor Transmission Rate: WVTR)

The water vapor permeability was measured by the Mocon method at 40℃and 90% RH. In the examples, the water vapor permeability of the packaging bag was measured in addition to the water vapor permeability of the laminate monomer, and the water vapor permeability of the packaging bag was measured without bag breakage in the impact resistance evaluation.

In all cases, recyclability was good. Examples and comparative examples provided with a gas barrier layer showed good OTR and WVTR, but comparative examples in which the base layer was a stretched film had a high rate of bag breakage in the impact resistance evaluation. On the other hand, the examples in which the base material layer was an unstretched film showed high impact resistance without bag breakage in the impact resistance evaluation. In addition, the packages of examples 2-3, in which the base material layer and the sealant layer were joined with a gas barrier adhesive, also maintained good OTR after severe impact resistance evaluation.

While the embodiments and examples of the present disclosure have been described above, specific configurations are not limited to the embodiments and examples, and modifications, combinations, and the like of configurations that do not depart from the scope of the gist of the present disclosure are also included in the present disclosure.

In addition, in the laminate of the present disclosure, a gas barrier layer is not necessary. That is, when used in a packaging material whose content does not require barrier properties, the gas barrier layer may be omitted. When the gas barrier layer is provided, a gas barrier coating layer is not necessarily required.

Symbol description

1 a base material layer, 2,9 an adhesive layer, 3 a sealant layer, 4 a print layer, 5 a primer layer, 6 a vapor deposition layer, 7 a gas barrier coating layer, 8 a resin layer, 9 an adhesive layer, 10 a gas barrier layer, 100, 200, 300, 400, 500, 600, 700, 800 a laminate, and 900 a stand-alone pouch.

Claims (15)

1. A laminate is provided with:

a substrate layer;

a sealant layer; and

an adhesive layer disposed between the base material layer and the sealant layer and in contact with the sealant layer,

wherein the substrate layer is composed of a material having a density of 0.940g/cm ³ An unstretched film comprising the polyethylene as a main component,

the sealant layer is formed of an unstretched film mainly composed of polyethylene,

The polyethylene is contained in the laminate in an amount of 90 mass% or more.

2. A laminate is provided with:

a substrate layer;

an adhesive layer provided on the first surface side of the base material layer; and

a sealant layer bonded to the adhesive layer,

wherein the base material layer and the sealant layer are unstretched films containing polyethylene as a main component, and the proportion of polyethylene in the laminate is 90 mass% or more.

3. The laminate according to claim 1 or 2, further comprising a gas barrier layer disposed between the base material layer and the adhesive layer.

4. A laminate according to claim 3, wherein the gas barrier layer comprises a vapour deposition layer.

5. The laminate of claim 4, wherein the evaporated layer comprises a metal oxide.

6. The laminate of claim 4, wherein the vapor deposition layer comprises silicon oxide.

7. The laminate according to any one of claims 4 to 6, wherein the gas barrier layer comprises a gas barrier coating layer disposed between the vapor deposition layer and the adhesive layer.

8. The laminate according to any one of claims 3 to 7, wherein the gas barrier layer comprises a gas barrier coating layer containing a water-soluble polymer.

9. The laminate according to any one of claims 1 to 8, wherein the adhesive layer is a layer formed of a cured product of a gas barrier adhesive.

10. The laminate according to any one of claims 1 to 9, further comprising a printed layer disposed between the base material layer and the sealant layer.

11. The laminate according to any one of claims 1 to 10, further comprising a resin layer which is disposed between the base layer and the sealant layer and is formed of an unstretched film mainly composed of polyethylene.

12. The laminate according to any one of claims 1 to 11, wherein a difference in thermal fusion bonding temperature between the base material layer and the sealant layer is 10 ℃ or higher.

13. A packaging bag obtained by bagging the laminate according to any one of claims 1 to 12.

14. The package of claim 13 which is for boiling.

15. A stand-up pouch formed using the laminate of any one of claims 1-12.