JP2021059080A - Laminate - Google Patents

Abstract

To provide a laminate that has high biodegradability, and has excellent adhesive strength even under a low humidity environment.SOLUTION: A laminate comprises a remoistening adhesive agent layer (I) 3 and a base material layer (II) 4, the remoistening adhesive agent layer (I) containing a modified starch (A) and a water-soluble polymer (B), and the modified starch (A) having an amylose content of at least 45 mass%. The water-soluble polymer (B) is a polyvinyl alcohol, or with respect to 100 pts.mass of the total of the modified starch (A) and the water-soluble polymer (B), the modified starch (A) content is 40-98 pts.mass and the water-soluble polymer (B) content is 2-60 pts.mass.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate containing a re-wet adhesive layer used for food packaging and the like, a multilayer laminate and an adhesive containing the laminate, a bag made of the adhesive, and a label, tape and the laminate made of the laminate. Regarding packaging materials such as lid materials and packaging auxiliary materials.

In food packaging, there are two methods for sealing the contents: a method of melt-adhering sealant layers such as heat seal and ultrasonic seal, and a method of joining with an adhesive material such as a hot melt adhesive. One of them is a sealing method using a re-wet adhesive layer typified by stamps, which is mainly used as a packaging auxiliary material. For example, as the re-wet adhesive layer, one using an acrylic polymer (Patent Document 1) and one using polyvinyl alcohol as a main component (Patent Document 2) are known. In addition, in food packaging, functions such as gas barrier properties are required to maintain the freshness of foods, and from the viewpoint of responding to environmental problems in recent years, the demand for biodegradability of packaging materials has increased remarkably. ing.

Japanese Patent No. 6423473 Japanese Patent Application No. 61-39354

However, although synthetic polymers such as polyvinyl alcohol have high strength, there is a problem that the biodegradability particularly required for packaging materials in recent years cannot be satisfied. On the other hand, starch, which is most often used as a re-wet adhesive layer, has a relatively high biodegradability and can be softened and dissolved in the presence of water. However, according to the study of the present inventor, the re-moisture adhesive layer is sufficiently brittle because it becomes extremely brittle in the humidity environment in which the food packaging material is placed, especially in a low humidity environment of 20 to 40% RH. It was found that the adhesive strength could not be obtained.

An object of the present invention is a laminate composed of a laminate having high biodegradability and excellent adhesive strength even when exposed to a low humidity environment, a multilayer laminate and an adhesive containing the laminate, and a bag composed of the adhesive. , And a label, tape and lid material made of the laminate.

As a result of diligent studies to solve the above problems, the present inventor has modified the re-wet adhesive layer (I) in the laminate containing the re-wet adhesive layer (I) and the base material layer (II). The present invention has been completed by finding that the above problems can be solved when the amylose content of the modified starch (A) containing the starch (A) and the water-soluble polymer (B) is 45% by mass or more. That is, the present invention includes the following aspects.

[1] A laminate containing a re-wet adhesive layer (I) and a base material layer (II).
A laminate in which the re-wet adhesive layer (I) contains a modified starch (A) and a water-soluble polymer (B), and the amylose content of the modified starch (A) is 45% by mass or more.
[2] The laminate according to [1], wherein the water-soluble polymer (B) is polyvinyl alcohol.
[3] Based on a total of 100 parts by mass of the modified starch (A) and the water-soluble polymer (B), the content of the modified starch (A) is 40 to 98 parts by mass, and the water-soluble polymer (B) is contained. The laminate according to [1] or [2], wherein the amount is 2 to 60 parts by mass.
[4] The laminate according to any one of [1] to [3], wherein the base material layer (II) is paper.
[5] A multilayer laminate containing the laminate according to any one of [1] to [4] and the layer (III), and having the re-wet adhesive layer (I) of the laminate on the outermost surface. , Multi-layer laminate.
[6] An adhesive in which the re-wet adhesive layer (I) and the adherend layer of the laminate according to any one of [1] to [5] are re-wet-bonded, and the adherend layer is: It is contained in a layer selected from the re-wet adhesive layer (I), the base material layer (II) and the layer (III) contained in the laminated body or another laminated body, or an adherend other than these laminated bodies. An adhesive that is a layer.
[7] The adhesive according to [6], wherein the adherend layer is a re-wet adhesive layer (I) contained in the laminated body or the other laminated body.
[8] A bag made of the adhesive according to [6] or [7].
[9] A label composed of the laminate according to any one of [1] to [5], and the outermost surface of the laminate opposite to the re-wet adhesive layer (I) is printed. ,label.
[10] A tape comprising the laminate according to any one of [1] to [5].
[11] A lid material made of the laminate according to any one of [1] to [5].

The laminate of the present invention is highly biodegradable and can have excellent adhesive strength even when exposed to a low humidity environment.

It is the schematic which shows the layer structure of the laminated body in one Embodiment of this invention. It is the schematic which shows the adhesive body (bag) and the manufacturing method thereof in one Embodiment of this invention. It is the schematic which shows the adhesive body (bag) and the manufacturing method thereof in one Embodiment of this invention. The schematic diagram of the twin-screw extruder used in an Example is shown.

[Laminate]
The laminate of the present invention is a laminate containing a re-wet adhesive layer (I) and a base material layer (II).
<Re-wet adhesive layer (I)>
The re-wet adhesive layer (I) is a layer that can be adhered by applying water. The laminate of the present invention can adhere the re-wet adhesive layer (I) at least partially by applying water.

The re-wet adhesive layer (I) contains the modified starch (A) and the water-soluble polymer (B), and the amylose content of the modified starch (A) is 45% by mass or more. Therefore, the laminate of the present invention is highly biodegradable and can have excellent adhesive strength even when exposed to a low humidity environment. Furthermore, it can also have excellent gas barrier properties. In the present specification, the adhesive strength indicates the adhesive strength when the re-wet adhesive layer is adhered to the adherend (adhesive layer) by re-wetting. Further, in the present specification, re-wetting means moistening (or wetting) the re-wet adhesive layer with water, and re-wet adhesion means moistening (or wetting) the re-wet adhesive layer with water. After that, it means to bond.

(Denatured starch (A))
As the modified starch (A), for example, at least one selected from the group consisting of etherified starch, esterified starch, cationized starch and crosslinked starch can be used.

Examples of starch include starch derived from cassava, corn, potato, sweet potato, sago, tapioca, morokoshi, beans, warabi, hass, hiss, wheat, rice, oat barley, arrowroot, pea and the like. Among them, starch derived from corn and cassava is preferable, and starch derived from high amylose corn is more preferable. Starch can be used alone or in combination of two or more.

Examples of the etherified starch include alkyl etherified starch such as methyl etherified starch; carboxyalkyl etherified starch such as carboxymethyl etherified starch; for example, etherification having a hydroxyalkyl group having 2 to 6 carbon atoms. Hydroxyalkyl etherified starch such as starch; and the like. Further, allyl etherified starch and the like can also be used.

Examples of the esterified starch include esterified starch having a structural unit derived from a carboxylic acid such as esterified starch having a structural unit derived from acetic acid; for example, esterified starch having a structural unit derived from maleic acid anhydride, phthalic acid anhydride. Esterified starch having structural units derived from dicarboxylic acid anhydrides such as esterified starch having structural units derived from it, esterified starch having structural units derived from octenyl succinic anhydride; for example, nitrate esterified starch, phosphoric acid ester Examples thereof include esterified starch having a structural unit derived from oxo acid such as esterified starch and urea phosphate esterified starch. Other examples include xanthate esterified starch, acetoacetic esterified starch and the like.

Examples of the cationized starch include a reaction product of starch and 2-diethylaminoethyl chloride, a reaction product of starch and 2,3-epoxypropyltrimethylammonium chloride, and the like.

Examples of the crosslinked starch include formaldehyde crosslinked starch, epichlorohydrin crosslinked starch, phosphoric acid crosslinked starch, achlorine crosslinked starch and the like.

As the modified starch (A), an etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms, an esterified starch having a structural unit derived from dicarboxylic acid anhydride, or a combination thereof is preferable, and hydroxyethyl Esterified starch, hydroxypropyl etherified starch, hydroxybutyl etherified starch, esterified starch with structural units derived from maleic anhydride, esterified starch with structural units derived from phthalic acid anhydride, derived from octenyl succinic acid anhydride Esterified starch having the structural unit of, or a combination thereof is more preferable. The modified starch (A) can be used alone or in combination of two or more.

The modified starch (A) has an amylose content of 45% by mass or more in the modified starch (A). Surprisingly, the present inventor found that the amylose content in the modified starch (A) contained in the re-wet adhesive layer (I) was 45% by mass or more, even when exposed to a low humidity environment. It has been found to have excellent adhesive strength. Further, when the amylose content is 45% by mass or more, it is advantageous from the viewpoint of gas barrier property and biodegradability. On the other hand, if the content of the amylose is less than 45% by mass, it is difficult to exhibit sufficient adhesive strength in a low humidity environment. When two or more types of modified starch are used, the amylose content of the modified starch (A) means the average amylose content obtained by weighted averaging the amylose content of the two or more types of modified starch. In this case, if the average amylose content is 45% by mass or more, the modified starch having an amylose content of less than 45% by mass may be contained.

The content of amylose in the modified starch (A) is preferably 50% by mass or more, more preferably 55% by mass or more, and further preferably 60% by mass or more. When the content of amylose in the modified starch (A) is at least the above lower limit, it is easy to increase the adhesive strength in a low humidity environment, and it is easy to improve the gas barrier property and the biodegradability. The content of amylose in the modified starch (A) is usually 90% by mass or less. In this specification, the amylose content can be measured by, for example, the iodine coloration method described in "Starch 50 No. 4 158-163 (1998)".

The modified starch (A) has a water content of preferably 10 to 15% by mass in the modified starch (A).

The etherified starch having a hydroxyalkyl group having 2 to 6 carbon atoms may be obtained by reacting starch with an alkylene oxide such as ethylene oxide, propylene oxide or butylene oxide. The average number of hydroxy groups used for denaturation is preferably 0.05-2 per glucose unit in starch.

As the modified starch (A), commercially available ones can also be used. Examples of typical commercial products of the modified starch (A) include ECOFILM®, which is a hydroxypropyl etherified starch available from Ingrediоn.

(Water-soluble polymer (B))
The water-soluble polymer (B) is a polymer compatible with the modified starch (A). The water-soluble polymer (B) preferably has a melting point suitable for the processing temperature of the modified starch (A), and polyvinyl alcohol is preferable from the viewpoint of easily increasing the adhesive strength and gas barrier property in a low humidity environment. The water-soluble polymer (B) can be used alone or in combination of two or more.

The degree of saponification of the polyvinyl alcohol is preferably 80 to 99.8 mol%. When the degree of saponification of polyvinyl alcohol is within the above range, it tends to be easy to increase the adhesive strength and gas barrier property in a low humidity environment. The degree of saponification is more preferably 85 mol% or more, further preferably 88 mol% or more, and particularly preferably 90 mol% or more. The degree of saponification indicates the mole fraction of the hydroxyl group with respect to the total of the hydroxyl group and the ester group in polyvinyl alcohol. Polyvinyl alcohol is produced, for example, by hydrolyzing polyvinyl acetate obtained by polymerizing a vinyl acetate monomer.

The viscosity of a 4% aqueous solution of polyvinyl alcohol measured according to JIS Z 8803 at 20 ° C. is preferably 1 to 50 mPa · s. When the viscosity of polyvinyl alcohol is within the above range, it tends to be easy to increase the adhesive strength and gas barrier property in a low humidity environment. The viscosity is more preferably 3 mPa · s or more, further preferably 5 mPa · s or more, more preferably 45 mPa · s or less, still more preferably 35 mPa · s or less.

Polyvinyl alcohol can further contain other monomer units other than vinyl alcohol units. Examples of other monomer units include monomer units derived from ethylenically unsaturated monomers. Examples of the ethylenically unsaturated monomer include α-olefins such as ethylene, propylene, n-butyl, isobutylene, and 1-hexene; allyl acid and salts thereof; unsaturated monomer having an allyl ester group; methacrylic acid. And salts thereof; unsaturated monomers having a methacrylic acid ester group; acrylamide, N-methylacrylamide, N-ethylacrylamide, N, N-dimethylacrylamide, diacetoneacrylamide, acrylamide propanesulfonic acid and its salts, acrylamidepropyldimethyl Amin and its salts (eg, quaternary salts); methalkylamide, N-methylmethacrylate, N-ethylmethacrylate, methallylamide propanesulfonic acid and its salts, methacrylicamidepropyldimethylamine and its salts (eg, quaternary salts); Methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, i-propyl vinyl ether, n-butyl vinyl ether, i-butyl vinyl ether, t-butyl vinyl ether, dodecyl vinyl ether, stearyl vinyl ether, 2,3-diacetoxy-1-vinyloxypropane, etc. Vinyl ethers; vinyl cyanide such as acrylonitrile and methacrylonitrile; vinyl halides such as vinyl chloride and vinyl fluoride; vinylidene halides such as vinylidene chloride and vinylidene fluoride; allyl acetate, 2,3-diacetoxy- Allyl compounds such as 1-allyloxypropane and allyl chloride; unsaturated dicarboxylic acids such as maleic acid, itaconic acid and fumaric acid and salts or esters thereof; vinylsilyl compounds such as vinyltrimethoxysilane, isopropenyl acetate; vinyl formate, acetic acid Vinyl, vinyl propionate, vinyl butyrate, vinyl isobutyrate, vinyl pivalate, vinyl versaticate, vinyl caproate, vinyl carlylate, vinyl laurate, vinyl palmitate, vinyl stearate, vinyl oleate, vinyl benzoate, etc. Vinyl ester monomers are exemplified. The content of the other monomer unit is preferably 10 mol% or less, and more preferably 5 mol% or less.

The method for producing polyvinyl alcohol is not particularly limited. For example, a method of polymerizing a vinyl alcohol monomer and optionally another monomer and saponifying the obtained polymer to convert it into vinyl alcohol units can be mentioned. Examples of the polymerization method at the time of polymerization include batch polymerization, semi-batch polymerization, continuous polymerization, semi-continuous polymerization and the like. Examples of the polymerization method include known methods such as a massive polymerization method, a solution polymerization method, a suspension polymerization method, and an emulsion polymerization method. Known methods can be applied to the saponification of the polymer. For example, it can be carried out in a state where the polymer is dissolved in alcohol or hydrous alcohol. The alcohol that can be used at this time is a lower alcohol such as methanol or ethanol.

The re-wet adhesive layer (I) has a modified starch (A) content of 40 to 98 parts by mass based on a total of 100 parts by mass of the modified starch (A) and the water-soluble polymer (B). Preferably, the content of the water-soluble polymer (B) is 2 to 60 parts by mass. When the content of the modified starch (A) and the content of the water-soluble polymer (B) are in the above ranges, the adhesive strength, biodegradability and gas barrier property in a low humidity environment can be easily enhanced.

The content of the modified starch (A) is preferably 45 parts by mass or more, more preferably 55 parts by mass or more, still more preferably 55 parts by mass or more, based on a total of 100 parts by mass of the modified starch (A) and the water-soluble polymer (B). It is 65 parts by mass or more, preferably 95 parts by mass or less, more preferably 93 parts by mass or less, and further preferably 90 parts by mass or less. When the content of the modified starch (A) is at least the above lower limit, the biodegradability is likely to be improved, and when it is at least the above upper limit, the gas barrier property and the adhesive strength in a low humidity environment are likely to be improved.

The content of the water-soluble polymer (B) is preferably 5 parts by mass or more, more preferably 7 parts by mass or more, still more preferably, based on a total of 100 parts by mass of the modified starch (A) and the water-soluble polymer (B). Is 10 parts by mass or more, preferably 55 parts by mass or less, more preferably 45 parts by mass or less, and further preferably 35 parts by mass or less. When the content of the water-soluble polymer (B) is at least the above lower limit, the gas barrier property and the adhesive strength in a low humidity environment are likely to be improved, and when it is at least the above upper limit, the biodegradability is likely to be improved.

In the re-wet adhesive layer (I), the total ratio of the modified starch (A) and the water-soluble polymer (B) is preferably 10% by mass or more with respect to the mass of the re-wet adhesive layer (I). It is more preferably 40% by mass or more, further preferably 60% by mass or more, particularly preferably 80% by mass or more, and preferably 100% by mass or less. When the total ratio of the modified starch (A) and the water-soluble polymer (B) is within the above range, the adhesive strength, biodegradability and gas barrier property in a low humidity environment can be easily enhanced.

The re-wet adhesive layer (I) may further contain a fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof. Examples of fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof include stearic acid, calcium stearate, sodium stearate, palmitic acid, lauric acid, myristic acid, linoleic acid, and behenic acid. Among these, stearic acid, calcium stearate, and sodium stearate are preferable from the viewpoint of processability. Fatty acids having 12 to 22 carbon atoms and fatty acid salts thereof can be used alone or in combination of two or more.

When the re-wet adhesive layer (I) contains a fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof, the content in the re-wet adhesive layer (I) is the re-wet adhesive layer. It is preferably 0.01 to 3% by mass, more preferably 0.03 to 2% by mass, and further preferably 0.1 to 1% by mass with respect to the mass of (I). When the content of the fatty acid having 12 to 22 carbon atoms and / or the fatty acid salt thereof is in the above range, it tends to be advantageous in terms of processability.

The re-wet adhesive layer (I) may further contain clay. Clays include synthetic or natural layered silicate clays such as montmorillonite, bentonite, byderite, mica, hectorite, saponite, nontronite, saponite, vermiculite, lady kite, magadite, kenyaite, stephensite, volcons Examples include koito. Clay can be used alone or in combination of two or more.

When the re-wet adhesive layer (I) contains clay, the content in the re-wet adhesive layer (I) is preferably 0.1 to 1 with respect to the mass of the re-wet adhesive layer (I). It is 5% by mass, more preferably 0.1 to 3% by mass, and even more preferably 0.5 to 2% by mass. When the clay content is in the above range, it tends to be advantageous in terms of transparency and strength.

The re-wet adhesive layer (I) can further contain a plasticizer. When a plasticizer is contained, it is easy to improve the film forming property and the coatability when forming the re-wet adhesive layer (I), and as a result, the layer having high adhesive strength in gas barrier property, re-wet adhesive property and low humidity environment. It is preferable because it tends to be. Examples of the plasticizer include water, sorbitol, glycerol, maltitol, xylitol, mannitol, glycerol trioleate, epoxidized linseed oil, epoxidized soybean oil, tributyl citrate, acetyltriethyl citrate, glyceryl triacetate, 2,2. , 4-trimethyl-1,3-pentanediol diisobutyrate, polyethylene oxide, polyethylene glycol and the like. The plasticizer can be used alone or in combination of two or more. Among these plasticizers, water is preferable from the viewpoint of gas barrier property, re-wet adhesive property, and easy to form a layer having high adhesive strength in a low humidity environment.

The water content (moisture content) in the re-wet adhesive layer (I) is preferably 3 to 20% by mass, more preferably 4 to 18% by mass, and further, with respect to the mass of the re-wet adhesive layer (I). It is preferably 7 to 15% by mass. When the water content is in the above range, it is advantageous in terms of gas barrier property, re-wet adhesive property, and adhesive strength in a low humidity environment. The water content is, for example, the water content when the humidity is adjusted at a temperature of 23 ° C. and a relative humidity of 50% for 2 weeks and then measured at a temperature of 130 ° C. for 30 minutes using a heat-drying moisture content meter.

The re-wet adhesive layer (I) can be used as a filler, processing stabilizer, weathering stabilizer, colorant, ultraviolet absorber, light stabilizer, antioxidant, antistatic agent, flame retardant, etc. Additives such as thermoplastic resins, lubricants, fragrances, defoaming agents, deodorants, bulking agents, release agents, mold release agents, reinforcing agents, cross-linking agents, mold retardants, preservatives, crystallization rate retarders, etc. Can be further included.

The form of the re-wet adhesive layer (I) is preferably in the form of a film or a sheet. The thickness of the re-wet adhesive layer (I) is preferably 0.01 μm or more, more preferably 0.1 μm or more, from the viewpoints of re-wet adhesiveness, adhesive strength in a low humidity environment, gas barrier property, biodegradability, and the like. It is more preferably 0.5 μm or more, particularly preferably 1 μm or more, preferably 1000 μm or less, more preferably 100 μm or less, still more preferably 50 μm or less, and particularly preferably 10 μm or less. Further, the re-wet adhesive layer (I) may be provided in one or two or more layers, and may be a single layer or a multilayer. When the re-wet adhesive layer (I) is two or more layers, the thickness and composition of each layer may be different or the same.

<Base layer (II)>
The base material layer (II) is not particularly limited, and examples thereof include paper and resin films. The paper is not particularly limited, and examples thereof include kraft paper, high-quality paper, imitation paper, glassin paper, parchment paper, synthetic paper, white paperboard, Manila ball, milk carton base paper, cup base paper, ivory paper, and silver paper. Among these, kraft paper, glassin paper, or the like can be preferably used from the viewpoint of easily improving the adhesion to the re-wet adhesive layer (I). The resin film is not particularly limited, and examples thereof include polyethylene terephthalate (PET) film, polypropylene (BOPP) film, polyethylene (PE) film (preferably low density polyethylene (LDPE) film), and polylactic acid film. Among these, the PET film can be preferably used from the viewpoint of easily improving the adhesion with the re-wet adhesive layer (I). The base material layer (II) is more preferably paper from the viewpoint of easily enhancing the adhesion and biodegradability with the re-wet adhesive layer (I).

The thickness of the base material layer (II) is not particularly limited, and is preferably 1 to 1000 μm, more preferably 1 to 500 μm, still more preferably 5 to 300 μm, and particularly preferably 10 to 150 μm. The base material layer (II) may be provided in one or more, and may be a single layer or a multilayer. When the base material layer (II) is two or more layers, the thickness and material of each layer may be different or the same.

The laminate of the present invention includes the re-wet adhesive layer (I) and the base material layer (II). Therefore, it is possible to achieve both high biodegradability and excellent adhesive strength after exposure to a low humidity environment. Moreover, the laminate of the present invention can also have excellent gas barrier properties.
The laminate of the present invention is partially or wholly re-moistened (for example, water is partially or wholly applied) to the re-wet adhesive layer (I) in the re-wet portion (water-applied portion). Adhesive function can be exhibited. Furthermore, even when exposed to a low humidity environment, it is possible to suppress a decrease in adhesive strength and maintain excellent adhesive strength. Therefore, for example, when the laminated body is in the form of a film or a sheet, various forms of packaging material or the like can be formed, or a label, seal or lid material or the like can be formed. Therefore, the laminate of the present invention is particularly useful as a packaging material for foods, a packaging auxiliary material, and the like.

The laminate of the present invention may include one or more adhesive layers (X) other than the re-wet adhesive layer (I) and the base material layer (II). Examples of the adhesive constituting the adhesive layer (X) include acrylic adhesive, urethane adhesive, epoxy adhesive, vinyl acetate adhesive, ethylene-vinyl acetate adhesive, vinyl chloride adhesive, and silicone. Examples thereof include based adhesives, nitrile cellulose-based adhesives, phenol-based adhesives, polyvinyl alcohol-based adhesives, melamine-based adhesives, and styrene-based adhesives, and urethane-based adhesives and the like are preferable from the viewpoint of adhesiveness. The thickness of the adhesive layer (X) is preferably 0.1 to 10 μm, more preferably 1 to 5 μm.

In one embodiment of the invention, when the laminate of the invention has an adhesive layer (X), the adhesive layer (X) is disposed between the re-wet adhesive layer (I) and the substrate layer (II). Is preferable. In a preferred embodiment of the invention, the laminate has a re-wet adhesive layer (I), an adhesive layer (X) and a substrate layer (II) in that order, or the re-wet adhesive layer (I) and Adjacent to the substrate layer (II). FIG. 1 shows a laminate that is a preferred embodiment of the present invention, that is, a laminate 2 in which the re-wet adhesive layer (I) 3, the adhesive layer (X) 5, and the base material layer (II) 4 are laminated in this order. Is shown.

The laminate of the present invention is excellent in gas barrier property, particularly oxygen barrier property. Oxygen permeability at 23 ℃ · 50% RH of the laminate of the present invention (mL.20μm ^/ m 2 .day.atm) is preferably 8.0 or less, more preferably 5.0 or less, more preferably 4. It is 0 or less, more preferably 3.0 or less, particularly preferably 2.0 or less, and most preferably 1.0 or less. When the oxygen permeability in the laminated body is not more than the above upper limit, excellent oxygen barrier property can be exhibited. The oxygen permeability (mL. 20 μm / m ^2. day. Atm) is usually 0.1 or more. The oxygen permeability of the laminate can be measured by an oxygen permeation measuring device after storing at 23 ° C. and 50% RH for two weeks to control the humidity, and can be measured by, for example, the method described in Examples.

The laminate of the present invention exhibits excellent adhesive strength (adhesiveness) when the re-wet adhesive layer (I) is adhered by re-wet adhesion, and has sufficient adhesive strength even when exposed to a low humidity environment. Can have. The seal strength after storing the laminate of the present invention in a low humidity environment of 23 ° C. and 20% RH for 3 days and adjusting the humidity is preferably 5 N / 15 mm or more, more preferably 8 N / 15 mm or more, still more preferably. It is 10 N / 15 mm or more. As for the sealing strength, two laminates having the same seal strength are prepared, water is applied to the re-wet adhesive layer (I) of one laminate, and then the water-applied portion and the other laminate are re-wet-bonded. The agent layer (I) is overlapped and press-bonded, stored at 23 ° C. and 20% RH for 3 days to control the humidity, and then under the conditions of a speed of 50 mm / min, an initial chuck distance of 50 mm, and a peeling angle of 180 °. , The delamination strength measured using a tensile tester, and can be measured by, for example, the method described in Examples.

[Manufacturing method of laminate]
The method for producing the laminate of the present invention is not particularly limited, but for example, after producing the re-wet adhesive layer (I), the adhesive layer (X) is formed on the obtained re-wet adhesive layer (I). , A method of forming a base material layer (II) on the adhesive layer (X) can be mentioned.

The re-wet adhesive layer (I) is, for example, a step (1) of mixing at least the modified starch (A) and a water-soluble polymer (B) to obtain a mixture, a step of extruding the mixture (2), and extrusion. It can be produced by a method including the step (3) of cooling and drying the mixture.

Step (1) is a step of mixing at least the modified starch (A) and the water-soluble polymer (B), and optionally other components, for example, the fatty acid having 12 to 22 carbon atoms and / or a fatty acid salt thereof. The clay, the plasticizer, and the additive can be mixed together.

Step (1) is usually performed using an extruder. In the extruder, each component is subjected to shear stress by a screw, and is uniformly mixed while being heated by applying external heat to the barrel.

As the extruder, for example, a twin-screw extruder can be used. The twin screw extruder may be co-rotated or reverse-rotated. The screw diameter may be, for example, 20 to 150 mm, and the ratio L / D ratio of the extruder length (L) to the screw diameter (D) may be, for example, 20 to 50. The rotation speed of the screw is preferably 80 rpm or more, more preferably 100 rpm or more. The extrusion molding pressure is preferably 5 bar (0.5 MPa) or more, more preferably 10 bar (1.0 MPa) or more. Each component can be introduced directly into the extruder. Further, each of these components may be premixed using a mixer and introduced into the extruder.

In the step (1), from the viewpoint of the film-forming property and the gas barrier property of the mixture, the lower limit is preferably 0.1% by mass or more, more preferably 1% by mass or more, and further preferably 10% by mass with respect to the mass of the mixture. As described above, it is possible to mix the plastic agent particularly preferably 15% by mass or more, most preferably 20% by mass or more, and the upper limit is preferably 50% by mass or less, more preferably 45% by mass or less, still more preferably 40% by mass or less. preferable. Preferred plasticizers include water. Here, the mass of the mixture indicates the total mass of the mixture containing the plasticizer. In the step (1), the plasticizer may be introduced at the initial stage of extrusion, or the plasticizer may be introduced before reaching the temperature at which the cooking treatment described later is performed, for example, at 100 ° C. or lower. The modified starch (A) can be gelatinized (gel) by being cooked by a combination of moisture, heat and shear stress. Further, by separately introducing a plasticizer, preferably water, the water-soluble polymer (B) can be dissolved, the mixture can be softened, and the modulus and brittleness can be reduced.

In the step (1), the cooking process is carried out by heating to a temperature of preferably more than 100 ° C. and 150 ° C. or lower, more preferably 115 ° C. or higher and 140 ° C. or lower. Here, the cooking treatment is a treatment in which starch granules are crushed and gelled. Heating can be performed by applying heat to the barrel of the extruder from the outside. By applying a stepwise temperature to each barrel, it can be heated to the desired temperature. When the cooking process is performed at a temperature of more than 120 ° C., it is advantageous in terms of workability.

The cooked mixture is preferably pushed towards the die while lowering to a temperature of preferably 85-120 ° C, more preferably 90-110 ° C to prevent foaming. Further, by exhausting from the barrel, foaming can be prevented and water can be removed.

The residence time in the extruder can be set according to the temperature profile and the screw speed, and is preferably 1 to 2.5 minutes.

In the step (2) of extruding the mixture, the molten mixture that has been pushed through the extruder while being melt-kneaded is extruded from the die. The temperature of the die is preferably 85-120 ° C, more preferably 90-110 ° C.

In the step (3) of cooling and drying the extruded mixture, the re-wet adhesive layer (I) can be formed by extruding the mixture into a film or a sheet. The extruded mixture is usually a melt.

When extruding the mixture into a film, the mixture can be extruded from a film forming die and then cooled and dried while being wound by a take-up roller. It is preferable to cool between the die and the roller so as to prevent the mixture from adhering to the roller. For drying, the rolls may be warmed or supplied with dehumidified air during winding. Dehumidified air can be used to inflate the film as it exits the die in the case of the blow tube method. Talc can also be included in the air stream to prevent film blocking.

The method for forming the adhesive layer (X) on the re-wet adhesive layer (I) is not particularly limited, but for example, an adhesive constituting the adhesive layer (X) is applied on the re-wet adhesive layer (I). Then, a method of drying or the like can be mentioned.

The method of forming the base material layer (II) on the adhesive layer (X) is not particularly limited, but for example, a method of laminating the base material layer (II) on the adhesive layer (X) and then laminating or the like. Can be mentioned. The laminate of the present invention may be produced by extruding the mixture onto the base material layer (II) using the above-mentioned extruder. Further, it may be produced by a sand laminating method in which the adhesive layer (X) is extruded between the re-wet adhesive layer (I) and the base material layer (II).

[Multi-layer laminate]
The present invention includes the laminate (including the re-wet adhesive layer (I) and the base material layer (II)) and the layer (III), and the re-wet adhesive layer (I) of the laminate is the most suitable. Includes multi-layer laminates on the surface. Since the multilayer laminate of the present invention has the re-wet adhesive layer (I) on the outermost surface, it can be partially or wholly adhered to the adherend by re-wetting (for example, application of water).

The layer (III) is not particularly limited as long as it is a layer other than the re-wet adhesive layer (I), the base material layer (II) and the adhesive layer (X), and examples thereof include a protective layer and re-wet. Examples thereof include a gas barrier layer, a moisture-proof layer, a light-shielding layer, a printing layer, a reinforcing layer, etc., which are different from the adhesive layer (I). Examples of the material forming the layer (III) include polyethylene, polypropylene, ethylene-vinyl acetate copolymer, EVOH, polyvinyl chloride, polyurethane, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate and other polyesters and nylon. Such as polyamide, polyacrylonitrile, cellulose or a derivative thereof, glass, wood and the like. The layer (III) may be provided in one or more layers, and may be a single layer or multiple layers. When the layer (III) is two or more layers, the thickness and material of each layer may be different or the same. The layer (III) may be laminated on the re-wet adhesive layer (I) or the base material layer (II) via the adhesive layer (X).

In the multilayer laminate of the present invention, it is preferable that at least one layer (III) is arranged on the outermost surface opposite to the re-wet adhesive layer (I). In such an embodiment, by decorating the surface of the layer (III) with characters, patterns, or the like, labels, stickers, packaging with characters, decorations, or the like can be formed.

The layer structure of the multilayer laminate of the present invention is not particularly limited, but is, for example, a re-wet adhesive layer (I) / adhesive layer (X) / base material layer (II) / adhesive layer (X) / layer (III). Layer structure having the re-wet adhesive layer (I) / base material layer (II) / adhesive layer (X) / layer (III) in this order; re-wet adhesive layer (I) / group Examples thereof include a layer structure having a material layer (II) / layer (III) / in this order. The thickness of the layer (III) is not particularly limited, but is preferably 1 to 1000 μm, more preferably 5 to 500 μm.

[Adhesives and bags]
The present invention includes an adhesive in which the re-wet adhesive layer (I) of the laminate (including the multilayer laminate) and the adherend layer are re-wet-bonded. The adherend layer is a layer selected from the re-wet adhesive layer (I), the base material layer (II) and the layer (III) contained in the laminated body or another laminated body, or a layer other than these laminated bodies. Examples include the layer contained in the adherend of. In other words, the adherend layer is a layer selected from the re-wet adhesive layer (I), the base material layer (II) and the layer (III) contained in the laminate; other laminates that are not the laminate. A layer selected from a re-wet adhesive layer (I), a base material layer (II) and a layer (III) contained in the body; a layer contained in an adherend that is neither the laminate nor the other laminate; Can be mentioned.
The present invention also includes a bag made of the adhesive. The other laminated body means the laminated body on the side to be adhered when two or more laminated bodies of the present invention are used.

The adhesive of the present invention is a laminate of the present invention in which the re-wet adhesive layer (I) and the adherend layer are re-wet-bonded. Since the adhesive of the present invention can maintain sufficient adhesive strength even when exposed to a low humidity environment, it can exhibit high strength even in such an environment. Furthermore, it is also excellent in biodegradability and gas barrier property. Hereinafter, a specific example of the adhesive (bag) of the present invention will be described. The adhesive body (bag) is not limited to the following aspects.

The adhesive shown in FIG. 2 is a two-sided bag made of one laminated body (film or sheet), and the laminated body 2a is bent in two and both ends are re-wet-bonded. The laminated body 2a is a laminated body having the layer structure shown in FIG.
As shown in FIG. 2, in the adhesive body 1a, water is applied from the re-wet adhesive layer (I) 3a side to the vicinity of the corresponding two sides on one side when the laminated body 2a is bent in half. Then, by folding the laminated body 2a in half, the coating portion 6a and the other re-wet adhesive layer (I) 3a (adhesion layer 8a) facing the coating portion 6a are formed. It is obtained by re-wet-bonding the bonded portion 7a of the above. Since both ends of the adhesive body 1a are adhered by the re-wet adhesive portion 9a, the adhesive body 1a functions as a bag.

Although FIG. 2 shows an embodiment in which the adherend layer 8a is the re-wet adhesive layer (I) contained in the same laminate, the portion where the coating portion 6a of the re-wet adhesive layer (I) is formed is shown. May be appropriately changed to prepare an adhesive (for example, a bag) using the base material layer (II) contained in the same laminate as an adherend layer. Further, although water is not applied to the bonded portion 7a in FIG. 2, water may be applied to the bonded portion 7a. Further, by changing the laminate 2a to a multilayer laminate and appropriately adjusting the formation location of the coating portion, the re-wet adhesive layer (I), the base material layer (II) or the layer contained in the same multilayer laminate is formed. An adhesive (for example, a bag) may be produced using (III) as an adherend layer.

The adhesive body (bag) shown in FIG. 3 is a three-sided bag composed of two laminated bodies (films or sheets), and the portions of the two laminated bodies 2b and 2c near the three sides are re-wet-bonded to each other. .. The laminated bodies 2b and 2c are laminated bodies having the layer structure shown in FIG. 1, respectively.
As shown in FIG. 3, in the adhesive body 1b, water is applied from the re-wet adhesive layer (I) 3b side to the vicinity of three sides of one laminated body 2b to form a coating portion 6b, and then the other By superimposing the laminate 2c from the re-wet adhesive layer (I) 3c side, the re-wet adhesive layer (I) 3c (adhesive layer) of the coating portion 6b and the other laminate 2c facing the coating portion 6b It is obtained by re-wet-bonding the bonded portion 7c in 8c). The adhesive body 1b functions as a bag because the vicinity of three sides is adhered by the re-wet adhesive portion 9b.

Although FIG. 3 shows an embodiment in which the adherend layer 8c is the re-wet adhesive layer (I) contained in the other laminated body, the formation of the coating portion 6b of the re-wet adhesive layer (I) is shown. An adhesive (for example, a bag) may be produced by appropriately adjusting the locations and using the base material layer (II) contained in the other laminated body 2c as an adherend layer. Further, although water is not applied to the bonded portion 7c in FIG. 3, water may be applied to the bonded portion 7c. Further, by changing at least the laminate 2c to a multilayer laminate and appropriately adjusting the formation location of the coating portion, the re-wet adhesive layer (I) and the base material layer (II) contained in the other multilayer laminate are formed. Alternatively, an adhesive (for example, a bag) may be produced by using the layer (III) as an adherend layer.

A laminate can be formed by using an adherend other than the laminate or the multilayer laminate of the present invention. For example, in the embodiment shown in FIG. 3, the adherend may be used instead of one of the laminates. Good. The adherend does not have at least the re-wet adhesive layer (I), and may be, for example, a film made of a base material layer (II) (particularly paper).

The number of laminates forming the adhesive of the present invention is not particularly limited, and is preferably 1 to 3, more preferably 1 or 2. Further, in the adhesive of the present invention, from the viewpoint of easily increasing the re-wet adhesiveness and the adhesive strength in a low humidity environment, the adherend layer is the re-wet adhesive layer (I) contained in the laminated body or another laminated body. Is preferable. The aspect shown in FIG. 2 is a re-wet adhesive layer (I) in which the adherend layer is contained in the laminate, and the embodiment shown in FIG. 3 is a re-wet adhesive layer in which the adherend layer is contained in another laminate. The agent layer (I). Although a bag is shown as an example in FIGS. 2 and 3, the mode of the adhesive is not limited to the bag.

The bag of the present invention is made of an adhesive in which the re-wet adhesive layer (I) of the laminated body and the adherend layer are re-wet-bonded (for example, FIGS. 2 and 3). In the bag of the present invention, of the total area of the re-wet adhesive layer (I) of the laminate, the area of re-wet adhesion with the adherend layer is preferably 1 to 90%, more preferably 5 to 40%. Is. When the area is within the above range, the volume as a bag can be secured while maintaining the adhesive strength.

The shape of the bag of the present invention is not particularly limited, but for example, a two-sided bag (FIG. 2), a three-sided bag (FIG. 3), a three-sided bag with a chuck, a gassho bag, a gusset bag, a bottom gusset bag, a stand bag, and a stand chuck bag. , Two-sided bag, four-sided pillar flat-bottomed gusset bag, side-seal bag, and bottom-seal bag.

[Labels, tapes and lids]
The present invention includes a label composed of the laminate and having a printed surface on the outermost surface of the laminate opposite to the re-wet adhesive layer (I). The present invention also includes a tape or a lid material made of the laminated body.

The label of the present invention functions as an adhesive label by re-wet bonding of the re-wet adhesive layer (I). Further, the decoration such as printed characters and patterns is not particularly limited. The printing method for forming the label of the present invention is not particularly limited, and examples thereof include a screen printing method, a flexographic printing method, and a gravure printing method. Since the label and tape of the present invention have the re-wet adhesive layer (I), they are excellent in re-wet adhesiveness.

The use of the lid material of the present invention is not particularly limited, and is preferably used for, for example, a lid material for a container. When used as a lid material for a container, the inside of the container can be sealed by combining with the container body. In particular, the lid material of the present invention is useful as a lid material for food containers because it has excellent gas barrier properties. Further, since the lid material of the present invention is also excellent in biodegradability, the environmental load can be reduced.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited to these aspects.

<Test method>
(1) Measurement of oxygen permeability The laminates obtained in Examples and Comparative Examples were stored at 23 ° C. and 50% RH for two weeks to adjust the humidity, and then attached to an oxygen permeability measuring device to measure oxygen permeability. did. The measurement conditions were as follows.
Equipment: "MOCON OX-TRAN2 / 20" manufactured by Modern Control Co., Ltd.
Temperature: 23 ° C
Humidity on oxygen supply side and carrier gas side: 50% RH
Oxygen pressure: 1.0 atm
Carrier gas pressure: 1.0 atm

(2) Biodegradability of the re-wet adhesive layer (I) Regarding the re-wet adhesive layer (I) obtained in Examples and Comparative Examples, carbon dioxide in biodegradation under aerobic conditions based on ISO14885-1. The following degree of biodegradation was derived from the amount of water generated.
Biodegradation (%) = (CO ₂ ) T-(CO ₂ ) B / MToT × CToT × 44/12 × 100
(CO ₂ ) T: Cumulative CO ₂ generation amount (g) discharged from the compost container
(CO _{2 ) B: Cumulative CO 2} generation amount (g) discharged from the blank test container
MToT: Amount of dry solids (g) of test material placed in compost container
CToT: Relative amount of total organic carbon (TOC) in the dry solid of the test material (g / g)

(3) Seal Strength under Low Humidity Two laminates obtained in Examples and Comparative Examples were cut out to a size of 150 mm × 150 mm. ^{On the re-wet surface of one of the two} sections, apply 5 g / m 2 of water to a region of 150 mm x 50 mm from the end of one side, and then overlap the other section with each side. The re-wet surfaces were overlapped with each other and pressed at a pressure of ^{1 kg / cm 2 to adhere them.} The pressed section was stored at 23 ° C. and 20% RH for 3 days to control the humidity, and then cut into a strip of 15 mm × 150 mm including an adhesive surface of 15 mm × 50 mm at the end to obtain a test piece. Delamination strength was measured with a tensile tester (Instron 3667, manufactured by Instron) under the conditions of a speed of 50 mm / min, an initial chuck distance of 50 mm, and a peeling angle of 180 °. The same test was performed a total of 5 times, and the average value was taken as the seal strength value.

(4) Material used <Modified starch (A)>
-ECOFILM (registered trademark): corn starch modified with propylene oxide, amylose content 70% by mass, obtained from Ingredition-National 7 (registered trademark): cassava starch modified with propylene oxide, amylose content 20% by mass, Obtained from Ingredion

<Example 1>
(Re-wet adhesive layer)
ECOFILM (registered trademark) (9.00 kg) and polyvinyl alcohol (solution viscosity 30 mPa · s, saponification degree 99%, 1.00 kg) were mixed in a tumbler mixer for 2 hours as raw materials, and the obtained mixture was used in a liquid pump. It was used in a connected twin-screw extruder. FIG. 4 shows a schematic view of the twin-screw extruder used in Example 1, and the screw diameter, L / D ratio, screw rotation speed, operation method, and temperature profile (Table 1) of the extruder are shown below. ..

Screw diameter: 27 mm
L / D ratio: 48
Screw rotation speed 500 rpm
Operation method: Co-rotation (engagement self-wiping) method

When the mixture was subjected to the twin-screw extruder, it was supplied into the barrel through the hopper in C1 at a speed of 3.5 kg / hour via the weight feeder of the twin-screw extruder. Water was injected into the barrel through a liquid pump (L) at C4 at a flow rate of 26 g / min. The temperature range of C5 to C9 is the cooking range, and complete gelatinization is completed within these bands. The take-up speed of the film extruded from the die was set so that the film had a thickness of 20 μm after cooling and drying. In this way, a re-wet adhesive layer (I) was obtained. The water content in the re-wet adhesive layer (I) is 12% by mass with respect to the mass of the re-wet adhesive layer (I). The water content is the water content when the humidity is adjusted at a temperature of 23 ° C. and a relative humidity of 50% for 2 weeks and then measured at a temperature of 130 ° C. for 30 minutes using a heat-drying moisture content meter.

(Laminated body)
An adhesive layer (X) is formed on the obtained re-wet adhesive layer (I) so that the thickness after drying is 3 μm, and kraft paper (basis weight 100 g / m ² ) is formed on the adhesive layer (X). A laminate was obtained by laminating (thickness 120 μm). The adhesive layer (X) was formed by applying a two-component adhesive using a bar coater and drying it. The two-component adhesive is a two-component reaction polyurethane adhesive consisting of "Takelac (registered trademark) A-520" manufactured by Mitsui Chemicals, Inc. and "Takenate (registered trademark) A-50" manufactured by Mitsui Chemicals, Inc. is there.

<Example 2>
A re-wet adhesive in the same manner as in Example 1 except that ECOFILM (registered trademark) (4.00 kg) and polyvinyl alcohol (solution viscosity 30 mPa · s, saponification degree 99%, 6.00 kg) were used as raw materials. A layer (I) and a laminate were obtained.

<Example 3>
A re-wet adhesive in the same manner as in Example 1 except that ECOFILM (registered trademark) (9.80 kg) and polyvinyl alcohol (solution viscosity 30 mPa · s, saponification degree 99%, 0.20 kg) were used as raw materials. A layer (I) and a laminate were obtained.

<Example 4>
Example 1 and Example 1 except that ECOFILM (registered trademark) (5.40 kg), National7 (3.6 kg) and polyvinyl alcohol (solution viscosity 30 mPa · s, saponification degree 99%, 1.00 kg) were used as raw materials. In the same manner, a re-wet adhesive layer (I) and a laminate were obtained.

<Example 5>
A re-wet adhesive layer (I) and a laminate were obtained in the same manner as in Example 1 except that ^{glassine paper (70 g / m 2} , thickness 70 μm) was used as the base material layer (II).

<Example 6>
A re-wet adhesive layer (I) and a laminate were obtained in the same manner as in Example 1 except that ^{thick paper (400 g / m 2} , thickness 570 μm) was used as the base material layer (II).

<Example 7>
The re-wet adhesive layer was the same as in Example 1 except that "Lumirror (registered trademark) P60" (thickness 12 μm) manufactured by Toray Industries, Inc., which is a stretched polyethylene terephthalate film, was used as the base material layer (II). (I) and a laminate were obtained.

<Comparative example 1>
Polyvinyl alcohol (solution viscosity 30 mPa · s, saponification degree 99%, 1.00 kg) is dissolved in hot water to a concentration of 10% by weight, and then placed in a mold on a flat plate to volatilize the water content to form a 20 μm film. Was obtained, and this was used as a re-wet adhesive layer (I). A laminate was obtained in the same manner as in Example 1.

<Comparative example 2>
A re-wet adhesive layer (I) and a laminate were obtained in the same manner as in Example 1 except that National 7 (10.0 kg) was used as a raw material.

<Comparative example 3>
A re-wet adhesive layer (I) and a laminate were obtained in the same manner as in Example 1 except that ECOFILM (registered trademark) (10.0 kg) was used as a raw material.

<Comparative example 4>
The re-wet adhesive layer (I) was the same as in Example 1 except that National 7 (9.0 kg) and polyvinyl alcohol (solution viscosity 30 mPa · s, saponification degree 99%, 1.00 kg) were used as raw materials. And a laminate was obtained.

Relates laminates of Examples 1-7 and Comparative Examples 1-4, its structure, and an oxygen permeability (mL.20μm ^/ m 2 .day.atm), rewetting adhesive layer biodegradability of (I) ( %) And the results of measuring the seal strength under 20% RH humidity control are shown in Table 2.

As shown in Table 2, the laminates obtained in Examples 1 to 7 have a higher degree of biodegradation than Comparative Example 1 and a higher sealing strength under low humidity than Comparative Examples 2 to 4. It was confirmed that. Therefore, it was confirmed that the laminates obtained in Examples 1 to 7 have high biodegradability and excellent re-wet adhesion even in a low humidity environment. Furthermore, it was confirmed that the laminates obtained in Examples 1 to 7 were also excellent in oxygen barrier properties.

<Making a bag>
Using the laminate obtained in Example 1, a two-sided bag as shown in FIG. 2 was produced. More specifically, the laminate obtained in Example 1 was cut out to a size of 150 mm × 300 mm, and the re-moisture adhesive layer (I) was placed inside and bent in the long side direction. ^{Next, after applying an amount of water of 5 g / m 2} with a width of 10 mm to the entire region of 6a shown in FIG. 2, the other section and each side overlap (the coated portion 6a and the adhered portion 7a). ^{A two-} sided bag was prepared by superimposing the re-wet surfaces on top of each other and pressing and adhering them at a pressure of 1 kg / cm 2. It was confirmed that this bag also has high biodegradability and excellent re-wet adhesion even in a low humidity environment.

1,1a, 1b ... Adhesive 2,2a, 2b, 2c ... Laminated 3,3a, 3b, 3c ... Re-wet adhesive layer (I)
4,4a, 4b ... Base material layer (II)
5 ... Adhesive layer (X)
6a, 6b ... Coating part 7a, 7c ... Adhesive part 8a, 8c ... Adhesion layer 9a, 9b ... Re-wet adhesive part

Claims (11)

A laminate containing a re-wet adhesive layer (I) and a base material layer (II).
A laminate in which the re-wet adhesive layer (I) contains a modified starch (A) and a water-soluble polymer (B), and the amylose content of the modified starch (A) is 45% by mass or more. The laminate according to claim 1, wherein the water-soluble polymer (B) is polyvinyl alcohol. Based on a total of 100 parts by mass of the modified starch (A) and the water-soluble polymer (B), the content of the modified starch (A) is 40 to 98 parts by mass, and the content of the water-soluble polymer (B) is 2. The laminate according to claim 1 or 2, which is ~ 60 parts by mass. The laminate according to any one of claims 1 to 3, wherein the base material layer (II) is paper. A multilayer laminate containing the laminate according to any one of claims 1 to 4 and the layer (III).
A multilayer laminate having the re-wet adhesive layer (I) of the laminate on the outermost surface. A bonded body in which the re-wet adhesive layer (I) and the adherend layer of the laminate according to any one of claims 1 to 5 are re-wet-bonded, and the adherend layer is the laminate or the like. Adhesive, which is a layer selected from the re-wet adhesive layer (I), the base material layer (II) and the layer (III) contained in the laminate, or a layer contained in an adherend other than the laminate. body. The adhesive according to claim 6, wherein the adherend layer is a re-wet adhesive layer (I) contained in the laminated body or the other laminated body. A bag made of the adhesive according to claim 6 or 7. A label made of the laminate according to any one of claims 1 to 5, wherein the outermost surface of the laminate opposite to the re-wet adhesive layer (I) is printed. A tape comprising the laminate according to any one of claims 1 to 5. A lid material comprising the laminate according to any one of claims 1 to 5.

Images