Laminate

Abstract

This laminate comprises: a first substrate layer made of paper or cloth; a first barrier layer made of a degradable resin containing at least one type of substance selected from the group consisting of a polyvinyl alcohol, an aliphatic polyester, and cellulose; and a second substrate layer made of paper or cloth, or a second barrier layer made of a biodegradable resin.

Description

Laminate

[0001] This invention relates to a laminate. This application claims priority based on Japanese Patent Application No. 2024-196388, filed in Japan on November 11, 2024, the contents of which are incorporated herein by reference.

[0002] Traditionally, many industrial products have used plastic (synthetic resin) materials synthesized from petroleum-derived raw materials. Due to their functionality and productivity, plastic materials are widely used in both daily life and industrial sectors. Therefore, when industrial products are no longer used, they have traditionally been disposed of as waste through landfill or incineration. However, some waste is disposed of through unauthorized methods such as dumping or open burning, which causes serious environmental pollution of the soil, water, and air, negatively impacting not only humans but also wildlife and plants, and posing a critical threat to their survival. For this reason, some industrial products using plastic (synthetic resin) materials are being reused, recycled, and reduced, with waste reduction measures being implemented through the circulation of the plastic materials themselves or a reduction in their usage. However, compared to cases where no waste reduction measures are taken, there have been difficulties (obstacles) in the widespread adoption and implementation of reduction measures, such as the costs of materials and processing required for reuse, recycling, and replacement, as well as potential problems with quality and functionality.

[0003] And in recent years, carbon dioxide (CO2), a greenhouse gas, has been identified as one of the causes of global warming. ２ The increase in carbon dioxide emissions is cited as a reason, and reducing carbon dioxide emissions requires setting national-level reduction targets. This is beginning to affect the way we live and work, and companies and other providers of products and services are taking steps to reduce carbon dioxide emissions. However, the progress of these measures varies depending on the circumstances of the company and the market, and in particular, companies, industries, and countries are required to develop policies that are adapted to carbon dioxide emission reduction technologies, the application environment of products, and the costs that arise from them.

[0004] In particular, materials used in the civil engineering and construction industry require durability, strength, and ease of installation under external environmental conditions, but until now, no materials have been available that meet the requirements for reducing carbon dioxide emissions. As a result, much of the plastic (synthetic resin) material that is used and discarded at civil engineering and construction sites is incinerated, and in recent years, the CO2 emissions from its combustion have become a concern. ２ This is becoming an environmental problem.

[0005] Materials used on civil engineering and construction sites include, for example, sheets used to cure concrete during construction (hereinafter referred to as concrete curing sheets) so that the concrete in buildings, facilities, and equipment can acquire the required strength and durability as a structural material. During concrete construction, it is necessary to maintain a temperature suitable for the hydration reaction of the cement contained in the concrete and to maintain a moist state that provides the moisture necessary for the hydration reaction, so that the concrete can sufficiently react and harden to achieve the required strength. The curing period for concrete varies depending on the composition of the cement and the environment during construction (temperature, humidity, sunlight, wind, weather), but generally, it is said that the longer the curing period under favorable conditions, the better the quality of the concrete.

[0006] However, conventional concrete curing sheets are often made of plastic (synthetic resin). And since most used concrete curing sheets are incinerated, a large amount of CO2 is released into the atmosphere as a result. ２ It emits waste, and it's hard to say that the environmental impact during disposal is small.

[0007] Furthermore, cement bags are used as materials for filling cement, the raw material for concrete, at civil engineering and construction sites. Cement bags are required to have water vapor barrier properties to prevent moisture absorption during cement storage, and mechanical strength to withstand drops from high places without tearing. However, no products are known that possess these functions while also having a low environmental impact when disposed of.

[0008] Patent Document 1 proposes a method for treating biodegradable resin molded products, characterized by immersing the resin molded product, which mainly consists of a biodegradable resin having ester bonds, in a weakly alkaline treatment solution as a pretreatment for biodegradation. According to Patent Document 1, this pretreatment, which generates less waste, can shorten the decomposition period in the natural environment, especially in the soil environment (promote decomposition).

[0009] Japanese Patent Publication No. 2024-89322

[0010] However, the treatment method described in Patent Document 1 requires the use of a weakly alkaline treatment solution, ultimately resulting in the generation of alkaline wastewater. Furthermore, the resins treated with alkali are limited to those containing ester bonds, making it unsuitable for use with biodegradable resins other than polyester. Additionally, biodegradable plastic films are less rigid than conventional polyethylene films, requiring bonding to increase their rigidity as a laminate. On the other hand, bonding the entire surface makes the film rigid and inflexible, making construction and bag making difficult. Thus, the issue of rigidity and flexibility in the use of biodegradable plastic films is a trade-off, making it difficult to achieve both simultaneously.

[0011] In view of the above circumstances, the present invention aims to provide a laminate that is highly degradable by microorganisms and enzymes in the soil, while also possessing both rigidity and flexibility.

[0012] The present invention provides a laminate containing a layer made of biodegradable resin, in which the entire surface is not bonded and unglued portions are left, thereby achieving both rigidity and flexibility in addition to biodegradability by microorganisms and enzymes in the soil. The present invention has the following embodiments. [1] A laminate comprising: a first base layer made of paper or cloth; a first barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and celluloses; and a second base layer made of paper or cloth, or a second barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and celluloses, wherein the laminate comprises: (i) the first base layer, the first barrier layer, and the second base layer in this order, wherein at least a portion between the first base layer and the first barrier layer is not bonded, and at least a portion between the first barrier layer and the second base layer is not bonded; or (ii) the first barrier layer, the first base layer, and the second barrier layer in this order, wherein at least a portion between the first barrier layer and the first base layer is not bonded, and at least a portion between the first base layer and the second barrier layer is not bonded. [2] The laminate according to [1], wherein the degradable resin is at least one resin selected from the group consisting of polyvinyl alcohol, polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polycaprolactone, polyhydroxybutyrate, polyethylene adipate, polyethylene terephthalate succinate, polyhydroxyalkanoate, polyglycolic acid, polytetramethylene adipate, methylcellulose, ethylcellulose, and acetylcellulose. [3] The laminate according to [1] or [2], wherein the degradable resin, when measured in accordance with ISO 17556, undergoes biodegradation of 90% or more within two years in soil under a composting environment at 25°C.[4] The laminate according to any one of [1] to [3], wherein the degradable resin is degraded into monomer units by at least one enzyme selected from the group consisting of lipase, cutinase, esterase, protease, lysophospholipase, amylase, glucoamylase, peptidase, serine hydrolase, cellulase, chitinase, xylanase, pectinase, peroxidase, monooxygenase, dioxygenase, and laccase. [5] The laminate according to [4], wherein the enzyme is derived from at least one microorganism selected from the group consisting of Pseudomonas, Pseudozyma, Cryptococcus, Bacteroides, Mucor, Fumicola, Thermomyces, Talaromyces, Cetomium, Torula, Sporotricum, Malbrancea, and Acidoborax. [6] The first barrier layer is a resin layer that prevents at least one selected from the group consisting of water vapor, gas, and heat, and has a water vapor transmission rate of 150 g / m at a temperature of 40 ± 0.5 °C and a relative humidity difference of 90 ± 2%. ２ - The oxygen permeability is 200 g / m³ or less, or at a temperature of 23°C and relative humidity of 0%. ２- A laminate according to any one of [1] to [5], wherein the thermal conductivity is 1.5 W / m·K or less, or measured in accordance with JIS A 1412-1:2016. [7] A laminate according to any one of [1] to [6], wherein the first base material layer includes at least one selected from the group consisting of fine paper, medium paper, kraft paper, coated paper, Kruppak paper, semi-bleached kraft paper, glassine paper, semi-glassine paper, clay coated paper, alkaline paper, cardboard, cotton cloth, silk cloth, wool cloth, linen cloth, jute cloth, hemp cloth, modal cloth, bamboo cloth, pineapple cloth, and ramie cloth. [8] A laminate according to any one of [1] to [7], wherein the first base material layer includes paper or cloth that is decomposed by cellulase or protease. [9] The laminate according to any one of items [1] to [8], wherein, when the laminate is formed into a bag, it does not rupture in a drop test method measured in accordance with JIS Z 0217, with a drop height of 1.2 m and fewer than 10 drops.

[10] The laminate according to any one of items [1] to [9], wherein the anti-slip angle of the first barrier layer is 20 degrees or more, as measured in accordance with the inclination method described in JIS P8147:2010.

[11] The laminate according to any one of items [1] to

[10] , wherein, when measured in accordance with ISO 17556, the biodegradability in soil under a compost environment at 25°C is 90% or more within 5 years.

[12] The laminate according to any one of items [1] to

[11] , wherein the thickness of the first base material layer is 50 to 200 μm.

[13] The laminate according to any one of items [1] to

[12] , wherein the thickness of the first barrier layer is 10 to 100 μm.

[14] A laminate according to any one of items [1] to

[13] used in the manufacture of construction materials, agricultural materials, fishing materials, general packaging materials, or general containers.

[15] A bag characterized by being made by forming a bag from the laminate according to [1] to

[14] using cotton yarn and water-soluble glue.

[0013] According to the present invention, it is possible to provide a laminate that is highly resistant to degradation by microorganisms and enzymes, while also possessing both rigidity and flexibility.

[0014] This is a cross-sectional view showing an example of a laminate according to one embodiment of the present invention. This is a front view showing an example of a laminate according to one embodiment of the present invention. This is a cross-sectional view showing another example of a laminate according to one embodiment of the present invention. This is a front view showing another example of a laminate according to one embodiment of the present invention. This is a cross-sectional view showing another example of a laminate according to one embodiment of the present invention. This is a cross-sectional view showing another example of a laminate according to one embodiment of the present invention. This is a front view showing an example of a bag made of a laminate according to one embodiment of the present invention. This is a front view showing another example of a bag made of a laminate according to one embodiment of the present invention. This is a cross-sectional view showing an example of machine-stitched construction of a laminate according to one embodiment of the present invention. This is a cross-sectional view showing an example of adhesive construction of a bag made of a laminate according to one embodiment of the present invention. This is a front view showing an example of a cement bag made of a laminate according to one embodiment of the present invention. This is a cross-sectional view showing an example of machine-stitched construction of a cement bag made of a laminate according to one embodiment of the present invention. This is a table showing the types of cement bags made of laminate according to one embodiment of the present invention. This is a table showing the performance of cement bags made of laminate according to one embodiment of the present invention. This is a table showing the dimensions and dimensional tolerances of machine-stitched cement bags made of laminate according to one embodiment of the present invention. This is a table showing the dimensions and dimensional tolerances of adhesive cement bags made of laminate according to one embodiment of the present invention.

[0015] <Laminate> The laminate of the present invention is a laminate having at least three layers, including a first base layer made of paper or cloth, a first barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and cellulose, and a second base layer made of paper or cloth or a second barrier layer made of a biodegradable resin. Hereinafter, the laminate shown in Figure 1 will also be referred to as the "first laminate," and the laminate shown in Figure 3 will be referred to as the "second laminate."

[0016] <First Laminate> The first laminate 1 of the present invention shown in Figure 1 (hereinafter also simply referred to as laminate 1) comprises the first base material layer 11, the first barrier layer 12, and the second base material layer 13 in this order. In the laminate 1 of the present invention shown in Figure 1, at least a portion between the first base material layer 11 and the first barrier layer 12 is not bonded and the unbonded portion 16 forms an air layer consisting of air, and at least a portion between the first barrier layer 12 and the second base material layer 13 is not bonded and the unbonded portion 17 forms an air layer consisting of air. In the laminate 1 of the present invention shown in Figure 1, the first base material layer 11 and the first barrier layer 12 are bonded via adhesive layers 14a and 14b at both ends, and the first barrier layer 12 and the second base material layer 13 are bonded via adhesive layers 15a and 15b at both ends. Figure 2 is a front view of the laminate 1 of the present invention. In the laminate 1 shown in Figure 2, each layer is bonded at both ends via adhesive layers 14a, 14b, 15a, and 15b. In the laminate 1 of the present invention, the ends may be sutured together with sutures instead of adhesive layers.

[0017] (First base material layer) In the laminate 1 shown in Figures 1 and 2, the first base material layer 11 is made of paper or cloth. Examples of paper or cloth include fine paper, medium paper, kraft paper, coated paper, crumb paper, semi-bleached kraft paper, glassine paper, semi-glassine paper, clay coated paper, alkaline paper, cardboard, cotton cloth, silk cloth, wool cloth, linen cloth, jute cloth, hemp cloth, modal cloth, bamboo cloth, pineapple cloth, and ramie cloth. Among these, kraft paper is preferred because it is made from recycled paper, further reducing the environmental impact, and has long fiber length and excellent mechanical strength.

[0018] It is preferable that the first base material layer 11 contains paper or cloth that is decomposed by cellulase or protease. By using paper or cloth that is decomposed by these enzymes, it becomes easier to decompose the laminate by more than 90% in about two years, even when it is buried in the soil.

[0019] Although not shown in the diagram, a printed layer may be provided on one surface 11a (outer surface) of the first substrate layer 11. The image formed on the printed layer is not particularly limited and may be represented by, for example, letters, patterns, symbols, or combinations thereof. The printed layer on the first substrate layer 11 can be formed using biomass-derived ink. This further reduces the environmental impact. The ink may contain enzymes or microorganisms for decomposing the biodegradable resin contained in the first barrier layer, which will be described later.

[0020] Furthermore, one side 11a of the first substrate layer 11 may be treated with a release agent such as a silicone-based release agent, a long-chain alkyl-based release agent, or a fluorine-based release agent, or a back surface treatment agent to improve release properties. In this case, even if multiple sheet-like (single-leaf) laminates 1 are stacked or a long laminate 1 is wound into a roll, the overlapping laminates 1 can be easily separated from each other.

[0021] The first base material layer 11 is preferably decomposed by 90% by mass or more within two years in soil under a composting environment at 25°C, as measured in accordance with ISO 17556, and more preferably by 95% by mass or more within two years. The biodegradability of the first base material layer 11 as described above makes it easier to reduce the environmental burden.

[0022] The thickness of the first base material layer is preferably 50 to 200 μm, more preferably 70 to 170 μm, and even more preferably 100 to 130 μm. If the thickness of the first base material layer is below the upper limit, the laminate is easily decomposed by microorganisms, enzymes, etc. If the thickness of the first base material layer is above the lower limit, it becomes easier to increase the mechanical strength required when the laminate is made into a product such as a bag. In this specification, dimensions can be measured in accordance with JIS Z 1531-1.

[0023] The basis weight of the first substrate layer is 30 to 150 g / m². ２ Preferably, 50 to 120 g / m ２ More preferably, 70-90 g / m ２This is even more preferable. If the basis weight of the first base material layer is within the above range, it is easier to handle the contents when the bag is filled with material. The tensile strength of the first base material layer is preferably 2.0 to 9.0 kN / m in the longitudinal direction and 1.0 to 4.5 kN / m in the transverse direction, measured in accordance with the method described in JIS P8113:2006, more preferably 3.0 to 7.0 kN / m in the longitudinal direction and 1.5 to 3.5 kN / m in the transverse direction, and even more preferably 4.0 to 5.5 kN / m in the longitudinal direction and 2.0 to 2.7 kN / m in the transverse direction. If the tensile strength of the first base material layer is within the above range, it is less likely to tear when pulled. The elongation of the first base material layer is preferably 0.8 to 4.0% in the longitudinal direction and 1.6 to 8.0% in the transverse direction, more preferably 1.4 to 3.3% in the longitudinal direction and 2.7 to 6.6% in the transverse direction, and even more preferably 2.0 to 2.5% in the longitudinal direction and 3.8 to 5.0% in the transverse direction, as measured according to the method described in JIS P 8113:2006. When the elongation of the first base material layer is within the above range, the bag is less likely to tear when filled with contents. The tear strength of the first base material layer is preferably 300 to 1600 mN in the longitudinal direction and 300 to 1700 mN in the transverse direction, more preferably 500 to 1200 mN in the longitudinal direction and 550 to 1300 mN in the transverse direction, and even more preferably 700 to 950 mN in the longitudinal direction and 750 to 1000 mN in the transverse direction, as measured according to the method described in JIS P 8116:2000. If the tear strength of the first base material layer is within the above range, it is likely to exhibit resistance to horizontal external impacts. The air permeability of the first base material layer is preferably 30 seconds or less, more preferably 25 seconds or less, and even more preferably 15 seconds or less. If the air permeability of the first base material layer is within the above range, when the contents are filled into the bag and palletized, the air inside the bag escapes, making it less likely for the contents to collapse and easier to prevent oxidation of the contents. In this specification, basis weight, tensile strength, elongation, tear strength, and air permeability can be measured in accordance with JIS P 3401, 8. (Test Method). In this specification, moisture resistance can be measured in accordance with JIS Z 0208 or JIS K 7129.

[0024] The first substrate layer 11 may have a coating layer on its surface. The coating layer may be laminated on the first substrate layer 11 as a film or sheet, or as a coating film (coat layer) by a coating method. The coating agent constituting such a coating layer may be a resin composition that further enhances biodegradability and reduces environmental impact, mainly consisting of a resin containing biodegradable components such as cellulose ester, shellac, rosin, or cellulose ester, wax, rosin, and polyaspartic acid, and may be mixed with a solvent such as water, and optionally, additives such as organic fillers, inorganic fillers, antioxidants, heat stabilizers, UV absorbers and other stabilizers, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, nucleating agents, and tackifiers, either individually or in combination of two or more, to the extent that they do not impair the effects of the present invention. Furthermore, inorganic components such as layered clay minerals and metal oxides may be added to the coating agent for the purpose of providing gas barrier properties. Specific examples of coating agents made from biologically derived components include SEIKOAT T-EF104, SEIKOAT T-EF103, and SEIKOAT T-EF201 (manufactured by Seikoh PMC Co., Ltd.). The coating method and coating apparatus for the above-mentioned coating agents are not particularly limited, and the conventionally known methods and their respective coating apparatuses can be used.

[0025] From the viewpoint of ease of forming the coating layer by extrusion molding or coating method, the MFR of the coating agent (load 2.16 kg, temperature 190°C) is preferably 1.0 to 20 g / 10 min. The thickness of the coating layer is preferably 0.005 mm (5 μm) or more and 5.0 mm or less, and more preferably 0.01 mm (10 μm) or more and 3.0 mm or less.

[0026] (First barrier layer) The first barrier layer 12 is a layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and cellulose. The first barrier layer 12 may be a resin layer for blocking at least one selected from the group consisting of water vapor, gas, and heat.

[0027] The first barrier layer 12 may be a film or sheet containing at least one biodegradable resin selected from the group consisting of polyvinyl alcohol, polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polycaprolactone, polyhydroxybutyrate, polyethylene adipate, polyethylene terephthalate succinate, polyhydroxyalkanoate, polyglycolic acid, polytetramethylene adipate, methylcellulose, ethylcellulose, and acetylcellulose. Preferably, the biodegradable resin is decomposed into monomer units by enzymes such as lipase, cutinase, esterase, protease, lysophospholipase, amylase, glucoamylase, peptidase, serine hydrolase, cellulase, chitinase, xylanase, pectinase, peroxidase, monooxygenase, dioxygenase, and laccase. The enzyme is preferably derived from microorganisms such as Pseudomonas, Pseudozyma, Cryptococcus, Bacteroides, Mucor, Fumicola, Thermomyces, Talaromyces, Cetomium, Torula, Sporotrichum, Malbrancea, and Acidoborax.

[0028] The biodegradable resin is preferably decomposed by 90% or more by mass within two years in soil under a composting environment at 25°C, as measured in accordance with ISO 17556, and more preferably by 95% or more by mass within two years. The biodegradability of the biodegradable resin makes it easier to reduce the environmental burden.

[0029] The nominal strain of the first barrier layer 12, measured in accordance with K 7161-1:2014, is preferably 100%, more preferably 150%, and even more preferably 200%. When the nominal strain is within the above range, when the laminate is formed into a bag, filled with contents, and transported, stretching due to friction occurs between the first and second base material layers, and the barrier layer stretches, thereby preventing tearing due to abrasion.

[0030] The thickness of the first barrier layer 12 is preferably 10 to 100 μm, more preferably 60 μm or less, and even more preferably 20 to 30 μm. When the thickness of the first barrier layer 12 is below the upper limit value, the laminate is likely to be decomposed by microorganisms, enzymes, etc. When the thickness of the first barrier layer 12 is above the lower limit value, it becomes easier to enhance the mechanical strength required when the laminate is made into a product such as a bag. Also, since it becomes easier to remove as foreign matter in the pulper line, the recyclability is likely to be improved.

[0031] The basis weight of the first barrier layer is preferably 10 to 170 g / m ２ more preferably 15 to 130 g / m ２ and even more preferably 25 to 100 g / m. When the basis weight of the first barrier layer is within the above range, it is easy to perform operations such as transportation even when the bag is filled with the contents. The tensile elongation of the first barrier layer is preferably 100% or more, more preferably 150% or more, and even more preferably 200% or more. When the elongation of the first barrier layer is within the above range, the barrier layer is difficult to break because it stretches when the bag is filled with the contents or when it is pulled. It is also likely to show resistance to impacts from the outside in the horizontal direction. The moisture-proof property of the first barrier layer is preferably 100 g / (m ２ ·24 h) or less, more preferably 60 g / (m ２ ·24 h), and even more preferably 40 g / (m ２ ·24 h). When the moisture-proof property of the first barrier layer is within the above range, it is easy to prevent the contents from absorbing moisture when the bag is filled with the contents. ２ When the first barrier layer 12 is a waterproof layer having waterproof properties, in the sprinkling test measured in accordance with JIS Z0302:1955, it is preferably 5 minutes or more, more preferably 30 minutes or more, and even more preferably 60 minutes or more. When the waterproof property is within the above range, in the product obtained from the laminate, it becomes a water-resistant packaging (resistant to rainfall and splashing) and it becomes easier to suppress the deterioration of the contents due to moisture.

[0032]

[0033] When the first barrier layer 12 is a thermal barrier layer having thermal barrier properties, the thermal conductivity measured in accordance with JIS A1412-1:2016 is preferably 1.5 W / m·K or less, more preferably 1.0 W / m·K, and even more preferably 0.3 W / m·K. When the thermal conductivity is within the above range, it becomes easier to suppress the deterioration of the contents due to heat in the product obtained from the laminate.

[0034] The first resin composition for forming the first barrier layer 12 for forming the first barrier layer may contain an additive. Examples of the additive include an enzyme, a microorganism, a coloring agent, a reinforcing agent (such as a glass filler), a slip agent, a stabilizer, a plasticizer, a flame retardant, an antistatic agent, a filler, a reinforcing agent, an antioxidant, an ultraviolet absorber, and a pigment.

[0035] Examples of the enzyme and the microorganism include those described above. The enzyme and the microorganism may be encapsulated in a capsule. It is preferable that they exhibit excellent physical properties without being biodegradable while the product made of the laminate of the present invention is being used, and biodegradation starts only when they flow out into the environment.

[0036] The MFR (Melt Flow Rate) (load 2.16 kg, temperature 190 °C) of the first resin composition for forming the first barrier layer 12 constituting the first barrier layer 12 is preferably 1.0 to 20.0 g / 10 min. In the case of film formation by inflation molding, it is more preferably 1.0 to 7.0 g / 10 min., and in the case of film formation by the T-die extrusion method, it is preferably 5.0 to 10 g / 10 min. When the MFR is within the above range, it is easy to form the first barrier layer 12 as a film.

[0037] With respect to the total mass of the resin composition for forming the first barrier layer, the content of the degradable resin is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 50% by mass or less. When the content of the degradable resin is within the above range, a large amount of the filler component to be contained as a filler can be filled. In particular, when the amount of the organic filler such as modified starch or wood powder increases, the surface area of the resin component of the obtained first barrier layer increases, which can promote the activities of enzymes and microorganisms and enhance the degradability, making it easier to reduce the environmental load. The content of the degradable resin may be 10% by mass or more, or may be 30% by mass or more. The first barrier layer can be produced by applying the resin composition for forming the first barrier layer to a substrate or the like and drying it, or can also be produced by extrusion molding.

[0038] The first barrier layer 12 may have a coating layer on its surface. Examples of the coating layer include the same ones as those described above.

[0039] (Second substrate layer) In the laminate 1 shown in FIGS. 1 and 2, the second substrate layer 13 is made of paper or cloth. Examples of the second substrate layer 13 include the same ones as those described for the first substrate layer 11.

[0040] The laminate 1 configured as described above may be in a sheet form (single leaf form) or may be a roll body formed by winding a long sheet, and its form is not limited, but can be appropriately selected in consideration of workability and handling properties.

[0041] (Air layer between the first substrate layer and the first barrier layer) In the laminate 1 of the present invention shown in FIG. 1, at least a part between the first substrate layer 11 and the first barrier layer 12 is not adhered, and at least a part between the first barrier layer 12 and the second substrate layer 13 is not adhered. In the laminate 1 of the present invention shown in FIG. 1, since at least a part between the first substrate layer 11 and the first barrier layer 12 is not adhered, an air layer composed of air is formed. By having the air layer, it is excellent in resistance to vertical impact, so that when the laminate is made into a bag and filled with contents, it is easy to prevent it from breaking and the contents from leaking.

[0042] The thickness of the air layer is preferably 2.0 mm or less, more preferably 1.0 mm, and even more preferably 0.1 to 0.5 mm. If the thickness of the air layer is below the upper limit, it becomes easier to increase the mechanical strength required when the laminate is made into a product such as a bag. If the thickness of the air layer is above the lower limit, the laminate is more likely to absorb moisture, and is more likely to decompose due to increased activity of microorganisms and enzymes.

[0043] (Adhesive layers 14a, 14b) In the laminate 1 of the present invention shown in Figure 1, the first base material layer 11 and the first barrier layer 12 are bonded together via adhesive layers 14a and 14b at both ends, and the first barrier layer 12 and the second base material layer 13 are bonded together via adhesive layers 15a and 15b at both ends. Figure 2 is a front view of the laminate 1 of the present invention. In the laminate 1 shown in Figure 2, each layer is bonded together at both ends via adhesive layers 14a, 14b, 15a, and 15b. The shape of the adhesive layers 14a and 14b is not particularly limited and may be continuous or discontinuous as shown in Figures 1 and 3. The position of the adhesive layers 14a and 14b is not limited to both ends, and may be near the four corners of the laminate or near the center of the laminate. If the laminate 1 can perform its function even without the adhesive layers 14a and 14b, then the adhesive layers 14a and 14b may not be provided. The laminate 1 of the present invention may have both ends sutured together with suture thread instead of an adhesive layer.

[0044] The adhesive layers 14a and 14b are formed from an adhesive. The adhesive may be a pressure-sensitive adhesive (also called a tack). The biomass content of the adhesive layers 14a and 14b is preferably 10% or more. Examples of biodegradable resins included in the adhesive layers 14a and 14b and the adhesive are the same as those mentioned for the first barrier layer 12 above. Examples of adhesives include the SAB20 series (20% biomass content), NS60 SBG85s SAB20, NS-PET50 SBG85s SAB20, NS80 SBG85S Super Strong CHR, NS80 SBG85S Super Strong CHR, NIPW55 C46S Super Strong CHR, Thermal B WHG65S Super Strong CHR (Elleair Texcel Co., Ltd.), TECHNOMELT PS 1212 series (Henkel Japan Ltd.), CHILL AT series (Lintec Corporation), and BPW6518 (Toyo-chem Co., Ltd.). These are usually supplied as adhesive sheets in roll form and can be bonded to the first barrier layer 12 by dry lamination. The thickness of the adhesive layers 14a and 14b is not particularly limited, but may be, for example, 5 to 100 μm.

[0045] The adhesive layers 14a and 14b can be laminated on the first barrier layer 12 as a coating film (coating layer). If the adhesive is in a form other than liquid or paste, for example, a heat-meltable solid adhesive such as powder, chip, or sheet, the solid adhesive can be placed on the surface of the first barrier layer 12 that is on the bonding side, and bonded by heat melting during bonding.

[0046] (Air layer between the first barrier layer and the second base material layer) In the laminate 1 of the present invention shown in Figure 1, at least a portion of the space between the first barrier layer 12 and the second base material layer 13 is not bonded. In the laminate 1 of the present invention shown in Figure 1, at least a portion of the space between the first barrier layer 12 and the second base material layer 13 is not bonded, which forms an air layer made of air. Having an air layer provides excellent impact resistance. The thickness of the air layer may be the same as that of the air layer described above.

[0047] (Adhesive layers 15a, 15b) In the laminate 1 of the present invention shown in Figure 1, the first barrier layer 12 and the second base material layer 13 are bonded together via adhesive layers 15a and 15b at both ends. Figure 2 is a front view of the laminate 1 of the present invention. In the laminate 1 shown in Figure 2, each layer is bonded together at both ends via adhesive layers 14a, 14b, 15a, and 15b. The adhesive layers 15a and 15b may be the same as those described above for adhesive layers 14a and 14b.

[0048] (Characteristics of the laminate) When laminate 1 is made into a bag, it is preferable that it does not rupture in a drop test method measured in accordance with JIS Z 0217 with a drop height of 1.2m and fewer than 10 drops, more preferably fewer than 15 drops, and even more preferably 20 drops or more. If the limit height is within the above range, it has excellent resistance to vertical impact, so when the laminate is made into a bag and filled with contents, it is easier to prevent it from rupturing and the contents from leaking.

[0049] The laminate 1 is preferably decomposed by 90% or more by mass within two years in soil under a composting environment at 25°C, and more preferably by 95% or more by mass within two years. The above-described biodegradability of the laminate makes it easier to reduce environmental impact.

[0050] When the laminate 1 is formed into a bag, it is preferable that the second base material layer 13 is arranged to face the second base material layer 13. This prevents the generation of static electricity due to friction between the bag and the contents when filled with dry powdered or particulate contents such as cement, wheat flour, or soybeans, thereby preventing a decrease in handling ease. Furthermore, since the first barrier layer 12 is laminated adjacent to the second base material layer 13, the first barrier layer 12 is positioned close to the contents. This makes it easier for the barrier properties (e.g., against water vapor, gas, and heat) to be exhibited, thus contributing to maintaining the quality of the contents.

[0051] <Second Laminate> The second laminate 2 of the present invention shown in Figure 3 (hereinafter also simply referred to as laminate 2) comprises the first barrier layer 21, the first base material layer 22, and the second barrier layer 23 in this order. In the laminate 2 of the present invention shown in Figure 3, at least a portion between the first barrier layer 21 and the first base material layer 22 is not bonded, and the unbonded portion 26 forms an air layer consisting of air, and at least a portion between the first base material layer 22 and the second barrier layer 23 is not bonded, and the unbonded portion 27 forms an air layer consisting of air. In the laminate 2 of the present invention shown in Figure 3, an air layer consisting of air is formed because at least a portion between the first barrier layer 21 and the first base material layer 22 is not bonded. In the laminate 2 of the present invention shown in Figure 3, an air layer consisting of air is formed because at least a portion between the first base material layer 22 and the second barrier layer 23 is not bonded. In the laminate 2 of the present invention shown in Figure 3, the first barrier layer 21 and the first base material layer 22 are bonded together via adhesive layers 24a and 24b at both ends, and the first base material layer 12 and the second barrier layer 23 are bonded together via adhesive layers 25a and 25b at both ends. The laminate 2 of the present invention may have both ends sutured together with sutures instead of adhesive layers. Figure 4 is a front view of the laminate 2 of the present invention. In the laminate 2 shown in Figure 4, each layer is bonded together at both ends via adhesive layers 24a, 24b, 25a, and 25b.

[0052] In the laminate 2 shown in Figures 3 and 4, the first barrier layer 21 and the second barrier layer 23 are the same as those described as the first barrier layer 12, respectively. In the laminate 2 shown in Figures 3 and 4, the first base material layer 22 is the same as those described as the first base material layer 11. In the laminate 2 shown in Figures 3 and 4, the air layer is the same as the air layer described in laminate 1. In the laminate 2 shown in Figures 3 and 4, the adhesive layers 24a, 24b, 25a, and 25b are the same as those described as adhesive layers 14a, 14b, 15a, and 15b.

[0053] When the laminated body 2 is formed into a bag, it is preferable that the second barrier layers 23 are arranged to face each other. This prevents liquid contents from seeping into the bag when it is filled, and also prevents leakage from the bag. Furthermore, since the first base material layer 22 is laminated adjacent to the second barrier layer 23, adhesion between the first barrier layer 21 and the second barrier layer 23 can be prevented. As a result, it is less likely to tear even when subjected to external impact.

[0054] The laminate of the present invention may have other layers. Other layers may be the same as the first base layer and the first barrier layer. The laminate of the present invention may also consist of multiple laminates stacked on top of each other. The laminate 10 shown in Figure 5 is formed by stacking two of the first laminates 1 shown in Figures 1 and 2. It is preferable that at least a portion between the first laminates 1 and the first laminates 1 is not bonded. It is preferable that an air layer made of air is formed between the first laminates 1 and the first laminates 1 by not bonding them. Adhesive layers 18a and 18b may be provided between the multiple laminates 1. Examples of adhesive layers 18a and 18b may be the same as adhesive layers 14a and 14b. If the laminate 10 can perform its function without adhesive layers 18a and 18b, then adhesive layers 18a and 18b may be omitted. The laminate 10 of the present invention may have both ends sutured together with sutures instead of adhesive layers. The laminate 20 shown in Figure 6 is formed by laminating two of the second laminates 2 shown in Figures 3 and 4. Preferably, at least a portion between the second laminates 2 is not bonded. Preferably, an air layer made of air is formed between the second laminates 2 by not bonding them. Adhesive layers 28a and 28b may be provided between the multiple laminates 2. Examples of adhesive layers 28a and 28b are the same as those for adhesive layers 14a and 14b. If the laminate 20 can perform its function without adhesive layers 28a and 28b, then adhesive layers 28a and 28b may be omitted. In the present invention, the laminate 20 may have both ends sutured together with suture thread instead of adhesive layers.

[0055] <Method for Manufacturing a Laminate> <Method for Manufacturing a First Laminate> The method for manufacturing a first laminate shown in Figure 1 of the present invention includes (i) laminating a first barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and cellulose onto a first base layer made of paper or cloth, and (ii) laminating a second base layer made of paper or cloth onto the side of the first barrier layer opposite to the first base layer.

[0056] Step (i) may include a step of providing an adhesive layer between the first substrate layer and the first barrier layer for bonding them together. Step (ii) may include a step of providing an adhesive layer between the first barrier layer and the second substrate layer for bonding them together.

[0057] If the first substrate layer has a coating layer, the process may include, before step (i), a step of forming a coating layer using a coating agent on both sides of the first substrate layer or on the side of the first substrate layer opposite to the side facing the first barrier layer. If the second substrate layer has a coating layer, the process may include, before step (ii), a step of forming a coating layer using a coating agent on both sides of the second substrate layer or on the side of the second substrate layer opposite to the side facing the first barrier layer.

[0058] <Method for manufacturing the second laminate> The method for manufacturing the second laminate shown in Figure 3 of the present invention includes (i') laminating a first base layer made of paper or cloth onto a first barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and cellulose; and (ii') laminating a second barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and cellulose onto the side of the first base layer opposite to the first barrier layer.

[0059] Step (i') may include a step of providing an adhesive layer between the first barrier layer and the first substrate layer for bonding them together. Step (ii') may include a step of providing an adhesive layer between the first substrate layer and the second barrier layer for bonding them together.

[0060] If the first substrate layer has a coating layer, the process may include a step of forming a coating layer on both or one side of the first substrate layer using a coating agent before step (i').

[0061] ≪Method for Decomposing the Laminate≫ The laminate of the present invention can be biodegraded by microorganisms and enzymes in the soil. While a biodegradation facility equipped with environmental control such as enzymes and temperature can be used for decomposition, it can also be decomposed by naturally growing bacteria by burying it in soil in a natural environment such as farmland or forest land. The soil should preferably contain microorganisms (biodegrading bacteria) that have the ability to decompose biodegradable resins, such as field soil or forest soil. Surface soil from a field or forest may be collected and moved to another location, or a standard soil may be prepared in accordance with JIS K 6955. Furthermore, compost may be mixed into the soil. It is desirable to perform prior measurements to determine the presence or absence of biodegrading bacteria or esterase activity. The compost is not particularly limited, but compost that has been sufficiently aerated in an aerobic composting plant is preferred.

[0062] Since microbial activity is temperature-dependent, the decomposition time varies depending on the season. However, for thin materials like film, more than 90% can be decomposed in about two years at an intermediate temperature of around 20°C. The decomposition properties of the laminate of this invention also include those certified A to E in the biodegradable resin certification conducted by TUV AUSTRIA.

[0063] Biodegradable resin certification is a system that certifies that a material meets the required standards, and test methods are described in standards such as ISO (JIS), EN, and ASTM. In Japan, there is a biodegradable plastic identification and certification system, and in Europe, there is the biodegradable resin certification implemented by TUV AustriA, among others. TUV AUSTRIA offers several certifications, listed in order of increasing difficulty in decomposition: OK compost INDUSTRIAL (biodegradable in urban waste disposal facilities, certified A), OK compost HOME (biodegradable in household compost, certified B), OK biodegradable SOIL (biodegradable using soil collected from fields and forests as a plant source, certified C), OK biodegradable WATER (biodegradable in activated sludge, certified D), and OK biodegradable MARINE (biodegradable in seawater, certified E). However, Japan's biodegradable plastic identification and certification system only covers those equivalent to certification A. In other words, Japanese certifications lump all biodegradable resins together as being equivalent to certification A, but this includes materials equivalent to certifications B and C. In Europe and the United States, this certification system is well-established, and there are systems in place to impose taxes on the use of materials and products that have not obtained certification. Therefore, some biodegradable resins distributed in Japan have obtained TUV AUSTRIA certification for global expansion. Some biodegradable resins are not only used individually, but also as composite materials, such as polymer alloys with other biodegradable resins, which possess properties that cannot be achieved individually. Some also have grades of biodegradability corresponding to each of the aforementioned certifications A to C. Therefore, regarding biodegradability, it is necessary to consider classifications based on the degree of biodegradability and appropriate processing methods for each classification, rather than the polymer name and its processing method. As a classification of biodegradability, using the requirements of the biodegradable resin certification implemented by TUV AUSTRIA is considered highly versatile and effective for industrial use, thus improving versatility. One of the requirements for certification A is that, when measured in accordance with ISO 14855 (JIS K 6953), "the degree of biodegradation becomes 90% or more within 6 months under an aerobic composting environment at 58°C."Certification B has a requirement that, when measured in accordance with ISO 14855 (JIS K 6953), "biodegradability reaches 90% or more within 12 months in a composting environment at 28°C." Certification C has a requirement that, when measured in accordance with ISO 17556, "biodegradability reaches 90% or more within 2 years in soil in a composting environment at 25°C." Certification D has a requirement that, when measured in accordance with ISO 14851 and ISO 14852, "biodegradability reaches 90% or more within 56 days in an aqueous culture solution (20°C to 25°C)." Certification E has a requirement that, when measured in accordance with ASTM D 6691, "biodegradability reaches 90% or more within 6 months in seawater (30°C)."

[0064] The biodegradable resin of the laminate of the present invention is not limited to biodegradable resins (those with certifications A to C) in Japanese certification, but also includes those with certifications A to E.

[0065] This invention can be implemented indoors or outdoors using simple temporary equipment, eliminating the need for dedicated processing facilities. It offers greater flexibility in terms of implementation location and shortens the biodegradation period (accelerating biodegradation) of degradable resins in natural environments, particularly soil environments, thus enabling low-cost processing. Furthermore, facilities such as final disposal sites can be utilized.

[0066] Examples of laminates of the present invention include combinations of the following layer configurations.

[0067]

[0068] ≪Applications of Laminates≫ The laminates of the present invention are used in the manufacture of construction materials, agricultural materials, fishing materials, general packaging materials, or general-purpose containers. Examples of construction materials include building packaging materials, protective films, packaging films, cushioning foams, packing materials, packing bags, bottles, pipe caps, rebar caps, and building material caps. Examples of agricultural materials include mulching films, tunnel films, greenhouse films, trellising nets, germination sheets, vegetation mats, seedling beds, and flower pots. Examples of fishing materials include fish boxes. Examples of general packaging materials include protective films, packaging materials, and packaging films. Examples of general-purpose containers include bags, trays, bottles, and cushioning foams. Many construction materials are one-way materials used at construction sites, such as cement bags, protective films, and protective sheets. Since these are generated at construction sites in various locations, collecting and centrally processing them requires time, effort, equipment, and high processing costs. Agricultural materials are generated at farms in various locations, so collecting and centrally processing them, like construction materials, requires time, effort, equipment, and high processing costs. This hinders the development of competitive agriculture. This invention is highly useful because it allows for the decomposition and processing of the laminated material at construction sites and near farms. Before decomposition, the material may be crushed into smaller pieces. Crushing increases the contact area with soil containing microorganisms and enzymes. This enhances the decomposition rate by microorganisms and enzymes, and makes it easier to shorten the time required for decomposition.

[0069] <Bag Body> Figures 7(a) to 7(i) are excerpts from "Figure 3 Types of Open-Top Bags" in JIS Z 0102:2004, and are front views showing examples of bag bodies formed from the laminate of the present invention. Note that JIS Z 0102:2004 is a standard for "Kraft paper bags - Vocabulary and types". As shown in Figures 7(a) to 7(i), the bag body formed from the laminate of the present invention may be a flat bag or a pleated bag. It may also be a machine-stitched bag or a glued bag. Furthermore, it may be an open-top bag. Here, a flat bag is a bag made of a flat tube. A pleated bag is a bag made of a gusseted tube. A machine-stitched bag is a bag that is closed on one or both ends by continuous machine stitching. A glued bag is a bag that is closed on one or both ends with glue. An open-type bag is a bag that is closed on only one end during the manufacturing process. The bags in Figures 8(a) to 8(i) are excerpts from "Figure 2 Types of bags with valves" in JIS Z 0102:2004. A bag with a valve is a bag that has a valve B formed as an opening for filling with contents, and is closed on both ends. Figures 9(a) to 9(f) are excerpts from "Figure 5 Sealing of machine-stitched bags" in JIS Z 0102:2004. As shown in Figures 9(a) to 9(f), the bag may be sealed by machine stitching after filling with contents. Figures 10(a) to 10(d) are excerpts from "Figure 6 Sealing of glued bags" in JIS Z 0102:2004. As shown in Figures 10(a) to 10(d), the contents may be filled and then sealed with adhesive.

[0070] <Cement Bag> Figures 11(a) and 11(b) are excerpts from "Figure 3 Shape and Dimensions of Paper Bags" in JIS Z 1505:2004. Note that JIS Z 1505:2004 is the standard for "Kraft paper bags - For cement". Figure 11(a) is an unfolded view showing an example of a cement bag formed from the laminate of the present invention, and Figure 11(b) is a front view of the cement bag when folded. Figure 12 is an excerpt from "Figure 1 Structure of the Sewing Section" in JIS Z 1505:2004. As shown in Figure 12, the cement bag of the present invention may be formed by folding the notch end on the valve side to form the valve opening, and then gluing crepe tape and reinforcing paper to the upper and lower ends and sewing them together.

[0071] Figure 13 is an excerpt from "Table 1 Types of Paper Bags" in JIS Z 1505:2004. In the cement bag of the present invention, the mass of the contents is preferably 50 kg or less, more preferably 40 kg or less, and even more preferably 25 kg or less. When the mass of the contents is below the above upper limit, the cement bag is less likely to tear, and the burden on the worker can be greatly reduced. The size of the cement bag of the present invention is preferably 1000 mm or less in length, 800 mm or less in width, and 100 mm or less in depth, more preferably 900 mm or less in length, 700 mm or less in width, and 90 mm or less in depth, and even more preferably 800 mm or less in length, 600 mm or less in width, and 80 mm or less in depth. When the length of the cement bag is within the above range, it is possible to make a cement bag that is less likely to tear, and a cement bag that is easy to handle.

[0072] Figure 14 is an excerpt from "Table 2 Properties of Paper Bags" in JIS Z 1505:2004. The seam strength of the cement bag of the present invention, in accordance with JIS Z 0215:1996, is preferably 1.0 kN or more, more preferably 1.3 kN or more, and even more preferably 2.0 kN or more. If the seam strength is above the above lower limit, the seams of the cement bag are less likely to tear, even when the mass of the contents of the cement bag is large, making it easier to prevent leakage of the contents. The bottom adhesive strength of the cement bag of the present invention, in accordance with JIS Z 1532:1998, is preferably 1.0 kN or more, more preferably 1.3 kN or more, and even more preferably 1.5 kN or more. If the bottom adhesive strength is above the above lower limit, the bottom adhesive of the cement bag is less likely to tear, even when the mass of the contents of the cement bag is large, making it easier to prevent leakage of the contents.

[0073] Figure 15 is an excerpt from "Table 3 Dimensions and Dimensional Tolerances for Machine-Sewn Bags" in JIS Z 1505:2004. The dimensional tolerance for the length of the bag is preferably ±30 mm or less, more preferably ±20 mm or less, and even more preferably ±10 mm or less. The dimensional tolerance for the width of the bag is preferably ±10 mm or less, more preferably ±8 mm or less, and even more preferably ±5 mm or less. The dimensional tolerance for the pleat width (depth) of the bag is preferably ±10 mm or less, more preferably ±8 mm or less, and even more preferably ±5 mm or less.

[0074] Figure 16 is an excerpt from "Table 4 Dimensions and Dimensional Tolerances of Adhesive Bags" in JIS Z 1505:2004. The dimensional tolerance for the length of the bag is preferably ±30 mm or less, more preferably ±20 mm or less, and even more preferably ±10 mm or less. The dimensional tolerance for the width of the bag is preferably ±10 mm or less, more preferably ±8 mm or less, and even more preferably ±5 mm or less. The dimensional tolerance for the pleat width (depth) of the bag is preferably ±10 mm or less, more preferably ±8 mm or less, and even more preferably ±5 mm or less.

[0075] <Concrete Curing Sheet> The concrete curing sheet formed from the laminate of the present invention can be used by attaching it to the surface of concrete. The first barrier layer 12, in particular, can suppress the evaporation and dissipation of moisture in the concrete during curing. In other words, it is possible to appropriately maintain the temperature and moisture state of the concrete during curing. As a result, it is possible to obtain concrete with a predetermined strength and durability while shortening the concrete curing period.

[0076] The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0077] The test and evaluation methods for each item are as follows: 1) Recyclability Test Method The test sample was placed in a sealed container and left for 8 hours to allow the paper to absorb sufficient moisture to facilitate defibration. At that time, sodium carbonate (soda ash) was added, and the pH was set to around 10, similar to the pulper process used in recycled paper recycling, and the water temperature was set to 40°C to promote the softening and defibration of the fibers. After 8 hours, the sealed container was stirred, and the defibration state of the pulp was observed using a mixer. The recyclability of the test sample was judged as appropriate according to the following evaluation items. ・Recyclability Evaluation Items Evaluation "○": The pulp fibers were defibrated and in a state where papermaking is possible, and even if there were foreign matter, it was small in amount and could be removed. Evaluation "×": A considerable amount of barrier layer film, etc., remained, making it difficult to remove in the recycled paper line.

[0078] 2) Biodegradability Test Method The test sample was placed in a 4 mm mesh polyethylene drain net and buried 20 cm above the top of the sediment layer in a test tank containing culture medium, and then observed. The test tank was kept under aerobic conditions and static conditions, the ambient temperature around the test sample was maintained at 60°C, and the moisture content of the culture medium was maintained at approximately 35%. The biodegradability of the test sample was judged appropriately according to the following evaluation items. ・Biodegradability Test Evaluation Items Evaluation "○": It was estimated that approximately 90% would decompose within two years. Evaluation "×": It was estimated that it would not decompose to 90% within two years, or would not decompose at all.

[0079] 3) Overall Evaluation Based on the evaluation results of recyclability and biodegradability, judgments were made as appropriate according to the following evaluation items. Evaluation "◎": Two "〇" ratings. Evaluation "〇": One "〇" rating. Evaluation "×": No "〇" ratings.

[0080] (Example 1) In Example 1, a test sample was prepared and evaluated with the following configuration. First layer: Kraft paper (manufactured by Oji Materia, product name: unbleached kraft paper, basis weight: 75 g / m²) ２ 1st layer: Thickness: 107 μm, Length: 100 mm, Width: 100 mm) 2nd layer: PVA film (Kuraray Co., Ltd., Product name: Poval Film #3500 VF-H (123), Thickness: 35 μm, Length: 100 mm, Width: 100 mm) 3rd layer: Kraft paper (Oji Materia Co., Ltd., Product name: Unbleached Kraft Paper, Basis weight: 75 g / m²) ２ Thickness: 107 μm, Length: 100 mm, Width: 100 mm. Adhesion: Machine sewing with cotton thread and combined use of water-soluble adhesive.

[0081] In the recycling suitability tests, it was confirmed that the kraft paper could be completely defibrated and converted into pulp fibers. The PVA film was completely dissolved, and it was confirmed that it no longer retained its film shape. The sewing thread retained its thread shape, but the amount was small and small enough to be easily removed in the recycled paper line. Based on these results, the recycling suitability was judged as "○".

[0082] In the biodegradation test, observations were conducted every month, and it was confirmed that after two months, approximately 80% of the kraft paper had disappeared and decomposed, losing its shape. The PVA film also completely dissolved, losing its shape. Approximately 80% of the sewing thread had also disappeared and decomposed, losing its shape. Based on these results, the biodegradability was judged to be "good".

[0083] (Example 2) In Example 2, a test sample was prepared and evaluated with the following configuration. First layer: Kraft paper (manufactured by Oji Materia, product name: unbleached kraft paper, basis weight: 75 g / m²) ２(Thickness: 107 μm, Length: 100 mm, Width: 100 mm) Second layer: Biodegradable film (VASU, Product name: VS-90-2-A6-1, Polybutylene adipate terephthalate, Thickness: 40 μm, Length: 100 mm, Width: 100 mm) Third layer: Kraft paper (Oji Materia, Product name: Unbleached Kraft Paper, Basis weight: 75 g / m²) ２ Thickness: 107 μm, Length: 100 mm, Width: 100 mm) Adhesion: Machine sewing with cotton thread and combined use of water-soluble adhesive

[0084] In the recycling suitability test, it was confirmed that the kraft paper could be completely defibrated and converted into pulp fibers. Regarding the biodegradable film, it was confirmed that it did not dissolve and retained its film shape. Its size also remained almost unchanged from its dimensions before the test. However, because the film was sufficiently thick, it was determined that it could be removed in the pulper line if fed into the waste paper recycling line in the size of a heavy bag. Regarding the sewing thread, it retained its thread shape, but the amount was small and it was confirmed that it was large enough to be easily removed as foreign matter in the waste paper recycling line. Based on the above results, the recycling suitability was judged to be "△".

[0085] In the biodegradation test, observations were conducted every month. After two months, it was confirmed that approximately 80% of the kraft paper had disappeared and decomposed, losing its shape. It was also confirmed that approximately 80% of the sewing thread had disappeared and decomposed, losing its shape. After two months, the biodegradable film showed some decomposition, but still maintained its shape well. After about four months, it was confirmed that the biodegradable film had decomposed to the point where it could no longer maintain its shape. Based on the above results, the biodegradability was judged to be "good".

[0086] (Comparative Example 1) In the comparative example, a test sample was prepared and evaluated with the following configuration. First layer: Kraft paper (manufactured by Oji Materia, product name: unbleached kraft paper, basis weight: 75 g / m²) ２ (Thickness: 107 μm, Length: 100 mm, Width: 100 mm) Second layer: PE film (Made by Nippon Polyethylene, Product name: HF335, Basis weight: 19 g / m²) ２(Thickness: 20 μm, Length: 100 mm, Width: 100 mm) Third layer: Kraft paper (manufactured by Oji Materia, product name: Unbleached Kraft Paper, basis weight: 75 g / m²) ２ Thickness: 107 μm, Length: 100 mm, Width: 100 mm) Adhesion: Machine sewing using synthetic fiber yarn (polyester yarn) and combined use of water-soluble adhesive.

[0087] In the recycling suitability test, it was confirmed that the kraft paper could be completely defibrated and converted into pulp fibers. Regarding the PE film, it was confirmed that it did not dissolve and retained its film shape. Its size also remained almost unchanged from its dimensions before the test. Furthermore, because the PE film is thin and easily torn, it was determined that if it were fed into the waste paper recycling line in the size of a heavy bag, it might be difficult to remove in the pulper line. Regarding the sewing thread, while it retained its thread shape, the amount was small and it was confirmed that it was large enough to be easily removed as foreign matter in the waste paper recycling line. Based on the above results, the recycling suitability was judged as "×".

[0088] In the biodegradation test, observations were conducted every month, and after two months, it was confirmed that approximately 80% of the kraft paper had disappeared and decomposed, losing its shape. However, the PE film and sewing thread did not decompose at all, and it was confirmed that the film retained its shape. Its size also remained almost unchanged from the dimensions before the test. Based on the above results, the biodegradability suitability was judged as "fail".

[0089]

[0090] As is clear from Table 2, both Examples 1 and 2 showed a "○" for biodegradability. Furthermore, Example 1 also showed a "○" for recyclability. On the other hand, Comparative Example 1 showed a "×" for biodegradability. In addition, although the laminates of Examples 1 and 2 used biodegradable plastic, they were both rigid and easy to form into bags, thus achieving a balance between rigidity and flexibility.

[0091] According to the present invention, it is possible to provide a laminate that is highly resistant to degradation by microorganisms and enzymes, while also possessing both rigidity and flexibility.

[0092] 1, 2 Laminate 11, 22 First base layer 12, 21 First barrier layer 13 Second base layer 23 Second barrier layer 14a, 14b, 24a, 24b Adhesive layer 16, 17, 26, 27 Unadhesive part 18a, 18b Adhesive layer B Valve B0 Valve opening 31 Sewing 32 Bag layer 33 Tape 34 Reinforcement thread 35 Adhesive 36 Heat seal 37 Bottom decorative paper 38 Crepe tape 39 Seam line 40 Fold line 41 Pleats 42 Reinforcement paper 43 Reinforcement thread or paper 44 Sewing thread 45 Flash cut tube 46 Gluing

Claims

1. A laminate comprising: a first base layer made of paper or cloth; a first barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and celluloses; and a second base layer made of paper or cloth, or a second barrier layer made of a biodegradable resin containing at least one selected from the group consisting of polyvinyl alcohol, aliphatic polyester, and celluloses, wherein the laminate comprises: (i) the first base layer, the first barrier layer, and the second base layer in this order, wherein at least a portion between the first base layer and the first barrier layer is not bonded, and at least a portion between the first barrier layer and the second base layer is not bonded; or (ii) the first barrier layer, the first base layer, and the second barrier layer in this order, wherein at least a portion between the first barrier layer and the first base layer is not bonded, and at least a portion between the first base layer and the second barrier layer is not bonded.

2. The laminate according to claim 1, wherein the degradable resin is at least one resin selected from the group consisting of polyvinyl alcohol, polylactic acid, polybutylene succinate, polybutylene adipate terephthalate, polycaprolactone, polyhydroxybutyrate, polyethylene adipate, polyethylene terephthalate succinate, polyhydroxyalkanoate, polyglycolic acid, polytetramethylene adipate, methylcellulose, ethylcellulose, and acetylcellulose.

3. The laminate according to claim 1, wherein the biodegradable resin, when measured in accordance with ISO 17556, undergoes biodegradation of 90% or more within two years in soil under a composting environment at 25°C.

4. The laminate according to claim 1, wherein the degradable resin is decomposed into monomer units by at least one enzyme selected from the group consisting of lipase, cutinase, esterase, protease, lysophospholipase, amylase, glucoamylase, peptidase, serine hydrolase, cellulase, chitinase, xylanase, pectinase, peroxidase, monooxygenase, dioxygenase, and laccase.

5. The laminate according to claim 4, wherein the enzyme is derived from at least one microorganism selected from the group consisting of the genera Pseudomonas, Pseudozyma, Cryptococcus, Bacteroides, Mucor, Fumicola, Thermomyces, Talaromyces, Cetomium, Torula, Sporotrichum, Malbrancea, and Acidoborax.

6. The first barrier layer is a resin layer that prevents at least one selected from the group consisting of water vapor, gas, and heat, and has a water vapor transmission rate of 150 g / m³ at a temperature of 40 ± 0.5 °C and a relative humidity difference of 90 ± 2%. ２ - The oxygen permeability is 200 g / m³ or less, or at a temperature of 23°C and relative humidity of 0%. ２ The laminate according to claim 1, wherein the thermal conductivity is 1.5 W / m·K or less, or the thermal conductivity measured in accordance with JIS A 1412-1:2016 is 1.5 W / m·K or less.

7. The laminate according to claim 1, wherein the first base material layer includes at least one selected from the group consisting of fine paper, medium paper, kraft paper, coated paper, crumb paper, semi-bleached kraft paper, glassine paper, semi-glassine paper, clay coated paper, alkaline paper, cardboard, cotton cloth, silk cloth, wool cloth, linen cloth, jute cloth, hemp cloth, modal cloth, bamboo cloth, pineapple cloth, and ramie cloth.

8. The laminate according to claim 1, wherein the first substrate layer includes paper or cloth that is decomposed by cellulase or protease.

9. The laminate according to claim 1, which, when the laminate is formed into a bag, does not rupture when subjected to a drop test method measured in accordance with JIS Z 0217, with a drop height of 1.2 m and fewer than 10 drops.

10. The laminate according to claim 1, wherein the first barrier layer has an anti-slip angle of 20 degrees or more, as measured in accordance with the inclination method described in JIS P8147:2010.

11. The laminate according to claim 1, wherein, when measured in accordance with ISO 17556, the degree of biodegradation in soil under a composting environment at 25°C reaches 90% or more within two years.

12. The laminate according to claim 1, wherein the thickness of the first substrate layer is 50 to 200 μm.

13. The laminate according to claim 1, wherein the thickness of the first barrier layer is 10 to 100 μm.

14. The laminate according to claim 1, used in the manufacture of construction materials, agricultural materials, fishing materials, general packaging materials, or general-purpose containers.

15. A bag characterized by being made by forming a bag from the laminate described in claims 1 to 14 using cotton yarn and water-soluble glue.

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