Laminate

Abstract

A laminate 10 has a layered structure in which an adhesive layer 15 is provided between two thermoplastic resin layers 11, 13, and is characterized in that: the adhesive layer 15 is formed from an adhesive in which a polyrotaxane is mixed; and an olefin-based resin is included at a proportion of 80 mass% or more in relation to the total amount of the laminate 10.

Description

Laminate

[0001] The present invention relates to a laminate, and more particularly to an olefin-based laminate that contains a large amount of an olefin-based resin and is suitable for producing a pouch by bonding using heat sealing or ultrasonic sealing.

[0002] Olefin-based resins, such as propylene-based resins and ethylene-based resins, have long been used in the packaging field, and since they are particularly easy to heat-seal, pouches having an unstretched olefin-based resin film as a sealant resin layer are widely produced.

[0003] Furthermore, since packaging materials such as pouches require strength properties such as puncture resistance, the unstretched olefin resin film described above is used in the form of a laminate in which a reinforcing film such as a stretched film is laminated on the unstretched olefin resin film. In such a laminate, the reinforcing film is laminated on the unstretched olefin resin film with a dry lamination adhesive or the like.

[0004] In recent years, environmental concerns have led to increased demand for material recyclability. Therefore, laminates using unstretched olefin-based resins are required to have as high an olefin-based resin content as possible and to be monomaterial, eliminating materials other than olefin-based resins as much as possible. This is because highly monomaterial laminates containing a large amount of olefin-based resin can be reused as olefin-based resins.

[0005] However, pouches made using laminates containing a large amount of olefin-based resin have low impact resistance and drop strength, and often break when dropped from a certain height, so improvements are needed.

[0006] In recent years, polymers with a molecular structure called polyrotaxanes have been developed. These polymers are molecular complexes in which a chain-like axial molecule penetrates the rings of multiple cyclic molecules, bulky groups are attached to both ends of the axial molecule, and the cyclic molecules cannot escape from the axial molecule due to steric hindrance. Such complexes are called supramolecules. Various applications have been proposed for polyrotaxanes.

[0007] For example, Patent Document 1 proposes a laminate for a vacuum insulation material in which a heat-sealing layer and a gas barrier layer are bonded together with a polyrotaxane-containing adhesive. In this laminate, the adhesive contains polyrotaxane, so the adhesive follows the expansion and contraction of each layer, preventing delamination and exhibiting excellent gas barrier properties.

[0008] Furthermore, Patent Document 2 proposes a cell packaging material having an outer layer made of polyrotaxane. This cell packaging material has improved abrasion resistance and scratch resistance because the outer layer is made of polyrotaxane rather than PET or Ny.

[0009] Furthermore, Patent Document 3 proposes a thermoplastic elastomer composition comprising a thermoplastic urethane elastomer containing polyrotaxane. Because this elastomer composition contains polyrotaxane, it is possible to produce molded articles with excellent elongation and strength.

[0010] As described above, various uses of polyrotaxanes have been proposed, but no study has been conducted on their incorporation into adhesives used in highly monomaterial laminates containing a large amount of olefin-based resins.

[0011] JP 2021-1650 A Patent No. 6153183 Patent No. 6655555

[0012] Therefore, an object of the present invention is to provide an olefin-based laminate that contains a large amount of olefin-based resin, is suitable for recycling, and is suitable for producing pouches that are excellent in impact resistance and drop strength. Another object of the present invention is to provide an olefin-based laminate that is mainly composed of olefin-based resin and that is obtainable by using an adhesive containing polyrotaxane.

[0013] According to the present invention, there is provided a laminate having a layer structure in which an adhesive layer is provided between two thermoplastic resin layers, the adhesive layer being formed from an adhesive containing polyrotaxane, and the laminate containing an olefin-based resin in an amount of 80 mass% or more based on the total amount of the laminate.

[0014] The laminate of the present invention (hereinafter referred to as the olefin-based laminate) preferably employs the following aspects: (1) The olefin-based resin is an ethylene-based resin or a propylene-based resin. (2) The olefin-based resin is a resin composition containing an ethylene-based resin and a propylene-based resin. (3) The adhesive layer contains polyrotaxane in an amount of less than 17% by mass. (4) The adhesive layer contains polyrotaxane in a urethane-based adhesive. (5) In the polyrotaxane, the functional group at the end of the cyclic molecule side chain is a hydroxyl group. (6) Of the two thermoplastic resin layers, one thermoplastic resin layer is an unstretched sealant film made of the olefin-based resin, and the other thermoplastic resin layer is formed from an unstretched or stretched film. (7) The other thermoplastic resin layer is formed from a stretched film, and the stretched film is provided with an inorganic or organic coating. (8) An intermediate thermoplastic resin layer is provided between the one thermoplastic resin layer and the other thermoplastic resin layer. (9) The other thermoplastic resin layer is a stretched film, the intermediate thermoplastic resin layer is an unstretched or stretched film, and at least one of the other thermoplastic resin layer and the intermediate thermoplastic resin layer is made of the olefin-based resin. (10) At least one of the stretched film forming the other thermoplastic resin layer or the stretched film forming the intermediate thermoplastic resin layer is provided with an inorganic coating or an organic coating.

[0015] The present invention also provides a pouch obtained from the above olefin-based laminate.

[0016] The olefin-based laminate of the present invention has a basic structure in which an adhesive layer is provided between two thermoplastic resin layers, and contains an olefin-based resin in an amount of 80 mass % or more based on the total mass of the laminate, which results in a high mono-material property of the olefin-based resin and excellent recyclability.

[0017] Furthermore, in the present invention, provided that the olefin resin content is within the above range, small amounts of materials other than olefin resins are used, and in particular, an adhesive containing polyrotaxane is used. As a result, the pouch (bag-shaped container) formed from this laminate, although made mostly of olefin resin, exhibits high drop strength and is effectively prevented from breaking when dropped from a high place.

[0018] The olefin-based laminate of the present invention can improve various properties required for packaging materials such as pouches by employing various layer structures suitable for packaging materials within the scope of satisfying the above-mentioned basic structure, etc.

[0019] The present invention relates to a method for manufacturing a laminate of a polyrotaxane, a method for manufacturing a laminate of a polyrotaxane, and a method for manufacturing a laminate of a polyrotaxane.

[0020] <Polyrotaxane> First, the polyrotaxane to be incorporated into the adhesive layer in the present invention will be described. Polyrotaxane is a known compound, and as shown in Figure 1, the polyrotaxane molecule, generally designated 1, has a composite molecular structure formed from a chain-like axial molecule 2 and cyclic molecules 3. That is, the chain-like axial molecule 2 is enclosed by a plurality of cyclic molecules 3, and the axial molecule 2 penetrates the interior of the ring of the cyclic molecule 3. Therefore, the cyclic molecule 3 can slide freely on the axial molecule 2, but bulky terminal groups 4 are formed on both ends of the axial molecule 2, preventing the cyclic molecule 3 from falling off the axial molecule 2.

[0021] In other words, because the cyclic molecules 3 can slide on the axial molecules 2, the adhesive layer containing polyrotaxane has a high degree of molecular freedom, making it easier to follow the expansion and contraction of adjacent layers and to distribute stress when a load is applied, which is a factor in improving impact resistance.

[0022] In such polyrotaxanes, various types of chain-like axial molecules 2 are known, and for example, they may be linear or branched as long as they can pass through the rings of the cyclic molecules, and are generally formed of a polymer.

[0023] Examples of polymers that form such an axis molecule 2 include polyvinyl alcohol, polyvinylpyrrolidone, cellulose-based resins (carboxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, etc.), polyacrylamide, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinyl acetal, polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch, olefin-based resins (polyethylene, polypropylene, etc.), polyester, polyvinyl chloride, styrene-based resins (polystyrene, acrylonitrile-styrene copolymer resin, etc.), acrylic resins (poly(meth)acrylic acid, Examples of the polymer include polymethyl methacrylate, polymethyl acrylate, acrylonitrile-methyl acrylate copolymer resin, polycarbonate, polyurethane, vinyl chloride-vinyl acetate copolymer resin, polyvinyl butyral, polyisobutylene, polytetrahydrofuran, polyaniline, acrylonitrile-butadiene-styrene copolymer (ABS resin), polyamide (nylon, etc.), polyimide, polydienes (polyisoprene, polybutadiene, etc.), polysiloxane (polydimethylsiloxane, etc.), polysulfone, polyimine, polyacetic anhydride, polyurea, polysulfide, polyphosphazene, polyketone, polyphenylene, polyhaloolefin, etc. These polymers may be copolymerized or modified as appropriate.

[0024] In the present invention, preferred polymers for forming the axis molecule 2 are polyethylene glycol, polyisoprene, polyisobutylene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, polypropylene, polyvinyl alcohol, and polyvinyl methyl ether, with polyethylene glycol being the most preferred in terms of affinity and reactivity with the adhesive in which the polyrotaxane is blended. Furthermore, polyethylene and polypropylene are preferred in terms of monomateriality.

[0025] Furthermore, examples of the bulky terminal groups 4 formed on both ends of the axial molecule 2 include an adamantyl group, a trityl group, a fluoresceinyl group, a dinitrophenyl group, and a pyrenyl group, with the adamantyl group being particularly preferred in terms of ease of introduction.

[0026] The molecular weight of the axial molecule is not particularly limited, but if it is too large, the affinity with the adhesive component tends to be poor, and if it is too small, the mobility of the cyclic molecule tends to decrease, and the effect of improving impact resistance tends to decrease. From this perspective, it is preferable that the weight average molecular weight Mw of the axial molecule 2 is in the range of about 1,000 to 100,000.

[0027] The cyclic molecule 3 may be any molecule having a ring large enough to include the axial molecule 2. Examples of such a ring include a cyclodextrin ring, a crown ether ring, a benzocrown ring, a dibenzocrown ring, and a dicyclohexanocrown ring, and a cyclodextrin ring is particularly preferred.

[0028] A plurality of such cyclic molecules 3 are included in one axial molecule 2, and generally, when the maximum number of cyclic molecules that can be included per axial molecule is taken as 1, the inclusion number of the cyclic molecules 3 is preferably in the range of 0.001 to 0.6, more preferably 0.002 to 0.5, and even more preferably 0.003 to 0.4. If the inclusion number of the cyclic molecules 3 is too high, the cyclic molecules 3 are densely present per axial molecule, which tends to reduce their mobility and decrease the impact resistance improving effect. On the other hand, if the inclusion number is too low, the gap between the axial molecules 2 becomes narrow, which also tends to reduce mobility and decrease the impact resistance improving effect.

[0029] The maximum number of clathrates of cyclic molecules 3 in one axis molecule 2 can be calculated from the length of the axis molecule 2 and the thickness of the rings of the cyclic molecules 3. For example, in the case where the axis molecule 2 is formed of polyethylene glycol and the rings of the cyclic molecules 3 are α-cyclodextrin rings, the maximum number of clathrates can be calculated as follows. That is, the repeating unit [-CH ２ -CH ２The thickness of two α-cyclodextrin rings is approximately the thickness of one α-cyclodextrin ring. Therefore, the number of repeating units is calculated from the molecular weight of the polyethylene glycol, and half of this number of repeating units is determined as the maximum inclusion number of the cyclic molecules. This maximum inclusion number is set to 1.0, and the inclusion number of the cyclic molecules is adjusted to be within the above-mentioned range.

[0030] In the present invention, the ring of the cyclic molecule 3 may have a side chain introduced therein. This side chain is indicated by 5 in FIG. 1 . That is, by introducing such a side chain 5 into the ring, it is possible to more reliably form an appropriate space between adjacent axial molecules 2, which is advantageous for improving impact resistance. Furthermore, the introduction of the side chain 5 can impart reactivity to the adhesive component to which the polyrotaxane is blended, forming a crosslinked structure with the adhesive, thereby further improving the strength of the formed pouch.

[0031] The side chain 5 is preferably formed by repeating an organic chain having a carbon number in the range of 3 to 20, and the weight average molecular weight of such a side chain is about 300 to 10,000.

[0032] The side chains 5 described above are introduced by utilizing functional groups possessed by the rings of the cyclic molecules 3 and modifying these functional groups. For example, an α-cyclodextrin ring has 18 hydroxyl groups as functional groups, and side chains are introduced via these hydroxyl groups. In other words, a maximum of 18 side chains can be introduced to one α-cyclodextrin ring. For example, if side chains are bonded to 9 of the 18 hydroxyl groups on an α-cyclodextrin ring, the degree of modification is 50%. This degree of modification is set within an appropriate range depending on the adhesive components used in combination.

[0033] In the present invention, the side chain 5 (organic chain) may be linear or branched, as long as the characteristic of polyrotaxane, that is, the sliding of the cyclic molecule 3 on the axial molecule 2, is not impaired. A side chain of an appropriate size can be introduced by reacting an appropriate compound with the functional group of the ring using ring-opening polymerization, radical polymerization, cationic polymerization, anionic polymerization, RAFT polymerization, NMP polymerization, or the like.

[0034] For example, by ring-opening polymerization, it is possible to introduce a side chain derived from a cyclic compound such as a cyclic lactone, a cyclic ether, a cyclic acetal, a cyclic amine, a cyclic carbonate, a cyclic iminoether, or a cyclic thiocarbonate. Among these, cyclic ethers, cyclic siloxanes, lactones, and cyclic carbonates are preferred from the viewpoints of easy availability, high reactivity, and ease of adjusting the size (molecular weight).

[0035] Although the compound used to introduce the side chain 5 by utilizing radical polymerization is a radical polymerizable compound, the ring of the cyclic molecule 3 of the polyrotaxane 1 does not have an active site that serves as a radical initiation point. Therefore, prior to reacting with the radical polymerizable compound, it is necessary to form an active site that serves as a radical initiation point by reacting the functional group (hydroxyl group) of the ring with a compound that forms a radical initiation point, such as an organic halogen compound.

[0036] As the radically polymerizable compound used for introducing a side chain by radical polymerization, a compound having at least one functional group such as a group having an ethylenically unsaturated bond, for example, a (meth)acrylic group, a vinyl group, or a styryl group (hereinafter referred to as an ethylenically unsaturated monomer) is preferably used.

[0037] As can be understood from the above explanation, the side chain 5 introduced into the ring of the cyclic molecule 3 may have a repeating unit introduced therein by an -O- bond, an -NH- bond, an -S- bond, or the like, or may have a substituent such as a hydroxyl group, a carboxyl group, an acyl group, a phenyl group, a halogen atom, a silyl group, a mercapto group, a vinyl group, an NCO group, or an NCS group, depending on the method of introduction. Furthermore, depending on the type of functional group possessed by the compound used to introduce the side chain 5, a portion of this side chain may bond to a functional group of the ring of a cyclic molecule possessed by another axis molecule, forming a pseudo-crosslinked structure.

[0038] In the present invention, the most preferably used polyrotaxane 1 has an axis molecule 2 made of polyethylene glycol having an adamantyl group bonded as an end group 4, a cyclic molecule 3 having an α-cyclodextrin ring, and further has a side chain 5 (terminated by an OH group) of polycaprolactone or the like introduced therein.

[0039] <Basic Structure> Referring to FIG. 2 , the olefin-based laminate 10 of the present invention, in which the above-mentioned polyrotaxane is used, has a basic structure in which an adhesive layer 15 is provided between two thermoplastic resin layers 11 and 13, provided that the laminate contains 80% by mass or more of an olefin-based resin, and in particular, 90% by mass or more of an ethylene-based resin or a polypropylene-based resin.

[0040] That is, since the laminate 10 of the present invention contains a very large amount of olefin-based resin, it has a high mono-material property and is highly recyclable. For example, when it is collected as waste after use, it can be appropriately crushed, washed, dried, etc., and then reused as an olefin-based resin again, either alone or mixed with virgin olefin-based resin, thereby suppressing deterioration of physical properties due to recycled use.

[0041] Thermoplastic resin layers 11, 13: In Fig. 1, an olefin resin is typically used to form the thermoplastic resin layers 11, 13 in order to achieve the aforementioned olefin resin content. Examples of this olefin resin include ethylene resins such as low-density polyethylene, high-density polyethylene, and copolymer resins of ethylene and other olefins; and propylene resins such as polypropylene and copolymer resins of propylene and other olefins. Of course, other olefin resins can also be used, but ethylene resins and propylene resins, which are widely used in the field of packaging materials, are preferred.

[0042] The olefin-based resin may be a resin composition containing an ethylene-based resin and a propylene-based resin, or the thermoplastic resin layer 11 may be formed from an ethylene-based resin or a propylene-based resin, and the thermoplastic resin layer 13 may be formed from a propylene-based resin or an ethylene-based resin. However, in order to enhance the monomateriality and achieve a form that is most suitable for recyclability, it is preferable to form the thermoplastic resin layers 11 and 13 using the same olefin-based resin.

[0043] Furthermore, in the present invention, the laminate 10 is suitable for producing a pouch 20 by using one thermoplastic resin layer 11 as a sealant resin layer and bonding the sealant resin layers together by heat sealing or ultrasonic sealing, as shown in FIG. 3 . In this case, the one thermoplastic resin (olefin-based resin) layer 11 used as the sealant resin layer is formed from an unstretched olefin. Furthermore, the other thermoplastic resin (olefin-based resin) layer 13 laminated with the adhesive layer 15 is preferably stretched to improve strength and heat resistance. Note that, in order to obtain a pouch that exhibits excellent heat resistance, particularly against heat treatments such as retort sterilization, and also has high strength, it is most preferable to use a propylene-based resin as the olefin-based resin.

[0044] In the olefin laminate 10 used to form the pouch 20, the unstretched olefin resin layer 11 (cast film) typically has a thickness of 30 to 150 μm. The other stretched olefin resin layer 13 (stretched film) is stretched and heat-set to an extent that improves strength and heat resistance, and typically has a thickness of about 10 to 30 μm.

[0045] Adhesive layer 15: In the olefin-based laminate 10 described above, the adhesive layer 15 is formed from an adhesive containing the polyrotaxane described above. That is, one olefin-based resin layer 11 (unstretched film) and the other olefin-based resin layer 13 (stretched film) are bonded together by this adhesive, so that a pouch 20 having excellent heat resistance, impact resistance, etc. can be obtained. Note that the adhesive layer 15 only needs to be present between the thermoplastic resin layers 11, 13, and does not necessarily have to be adjacent to these resin layers 11, 13.

[0046] The adhesive to be blended with the polyrotaxane is not particularly limited, and a dry lamination adhesive such as a urethane-based adhesive or an epoxy-based adhesive can be used. However, in order to make the most of the properties of the polyrotaxane, it is preferable to use a urethane-based adhesive.

[0047] In particular, the urethane adhesive has a functional group such as an epoxy group, an episulfide group, a thietanyl group, an OH group, an SH group, or an NH group on the side chain 5 of the polyrotaxane. ２ This is effective when a group, an NCO group, or an NCS group is introduced into the side chain 5 of the polyrotaxane. For example, polyurethane is formed by the reaction of a polyol with a polyisocyanate. That is, when the above-mentioned functional group is introduced into the side chain 5 of the polyrotaxane, the side chain 5 of the polyrotaxane is incorporated into the polymer chain of polyurethane formed by the reaction of the polyol with the polyisocyanate, thereby forming a crosslinked structure, which is most suitable for improving the strength of the pouch.

[0048] The polyol used to form the polyurethane adhesive is a compound having two or more OH groups per molecule, such as di-, tri-, tetra-, penta-, or hexa-hydroxy compounds, polyesters containing two or more OH groups per molecule (polyester polyols), polyethers containing two or more OH groups per molecule (hereinafter referred to as polyether polyols), polycarbonates containing two or more OH groups per molecule (polycarbonate polyols), polycaprolactones containing two or more OH groups per molecule (polycaprolactone polyols), and acrylic polymers containing two or more OH groups per molecule (polyacrylic polyols). The most suitable polyol for the present invention is polyester polyol because of its high affinity with polyrotaxanes.

[0049] The polyester polyols described above are polymers obtained by the condensation reaction of a polybasic acid such as adipic acid or phthalic acid with a polyol. Examples of the polyol to be reacted with the polybasic acid include aliphatic polyols such as ethylene glycol, propylene glycol, neopentyl glycol, and pentaerythritol; aromatic alcohols such as dihydroxynaphthalene, trihydroxynaphthalene, and bisphenol A; and sulfur-containing polyols such as bis-[4-(hydroxyethoxy)phenyl]sulfide.

[0050] The polyisocyanate to be reacted with the polyol is a compound having two or more NCO groups in one molecule. Specific examples thereof include, but are not limited to, aliphatic isocyanates such as ethylene diisocyanate, trimethylene diisocyanate, and tetramethylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate, norbornane diisocyanate, bis(isocyanatemethyl)cyclohexane, and 2-isocyanatemethyl-3-(3-isocyanatepropyl)-5-isocyanatemethyl-bicyclo[2,2,1]-heptane; aromatic isocyanates such as xylylene diisocyanate, bis(isocyanateethyl)benzene, bis(isocyanatemethyl)naphthalene, and bis(isocyanatemethyl)diphenyl ether; sulfur-containing aliphatic isocyanates such as thiodiethyl diisocyanate; and bis[2-(isocyanatemethyl) aromatic disulfide isocyanates such as diphenyl disulfide-4,4'-diisocyanate; aromatic sulfone isocyanates such as diphenyl sulfone-4,4'-diisocyanate; sulfonic acid ester isocyanates such as 4-methyl-3-isocyanate benzenesulfonyl-4'-isocyanate phenol ester; aromatic sulfonic acid amide isocyanates such as 4-methyl-3-isocyanate benzenesulfonylanilide-3'-methyl-4'-isocyanate; sulfur-containing heterocyclic isocyanates such as thiophene-2,5-diisocyanate; and the like.

[0051] The above-mentioned polyisocyanate is usually used in an amount such that the amount of isocyanate groups (NCO groups) is about 0.8 to 1.2 moles per mole of hydroxyl groups contained in the above-mentioned polyol.

[0052] In the present invention, the polyrotaxane is preferably present in an amount of less than 17% by mass, particularly less than 10% by mass, in the adhesive layer 15 formed from the above-mentioned adhesive (for example, a urethane adhesive obtained from a polyester polyol and a polyisocyanate). When the polyrotaxane is present in such an amount, the stress dispersion effect due to the sliding of the cyclic molecules 3 of the polyrotaxane is fully exerted, improving, for example, impact resistance and effectively suppressing breakage of the pouch 20 due to dropping.

[0053] It has been confirmed in the examples described below that adhesive coatings containing polyrotaxane in the amounts described above have improved loss tangent (tan δ) and vibration absorption properties in a dynamic viscoelasticity test (10 Hz) at 5° C. For example, in Examples 1 to 4 described below, polyrotaxane is blended into a urethane adhesive, and adhesive coatings containing such polyrotaxane exhibit a loss tangent (tan δ) of 0.21 or more, particularly 0.23 or more, in a dynamic viscoelasticity test (10 Hz) at 5° C., thereby improving vibration absorption properties.

[0054] Furthermore, in order to function as a strong bond between films, an adhesive coating containing polyrotaxane in the amount described above and having improved vibration absorption properties preferably has an elastic modulus equivalent to that of an adhesive coating that does not contain polyrotaxane. However, as shown in the results of the Examples described below, the adhesive coatings of Examples 1 to 4 have a storage modulus E' in a dynamic viscoelasticity test (10 Hz) at 5°C of more than 1 GPa, similar to Comparative Example 1 in which an adhesive coating that does not contain polyrotaxane is used.

[0055] In the present invention, the adhesive containing the polyrotaxane described above is used by adding the polyrotaxane to the reactive components that form the adhesive (for example, a coating composition in which a polyester polyol and a polyisocyanate are dispersed in an organic solvent). That is, the polyrotaxane-containing coating composition is applied to a film that forms one of the olefin-based resin layers, and then a film that forms the other olefin-based resin layer is pressed onto the film and heated to an appropriate temperature to polymerize and harden the film and remove the solvent, thereby forming an adhesive layer 15 and forming an olefin-based laminate 10 shown in FIG. 2 in which the thermoplastic resin layer 11 and the thermoplastic resin layer 13 are bonded together by the adhesive layer 15.

[0056] In such a laminate 10, the thickness of the adhesive layer 15 is very thin, and of course, the thickness is within a range that satisfies the above-mentioned olefin-based resin content in the laminate 10. For example, it is generally 2 to 5 g / m ２ It is about that thick.

[0057] <Bag manufacturing of olefin-based laminate> The olefin-based laminate 10 of the present invention described above can be used for various purposes as a packaging material, but most preferably, it is manufactured into a bag by attaching the unstretched thermoplastic resin layer 11 by heat sealing or ultrasonic sealing, and used as a pouch (bag-like container) 20.

[0058] Bags are made by known means. For example, an empty pouch is made by sealing two sheets of the olefin-based laminate 10, 10 on three sides, the contents are filled through the opening, and the opening is finally closed by heat sealing. Alternatively, an empty pouch can be made by folding back a single sheet of the olefin-based laminate 10 and heat sealing both side edges. In this case, it is not necessary to heat seal the bottom. Furthermore, an empty pouch can be made using an olefin-based laminate 10 dedicated to the sides or bottom. Such a method is advantageous in increasing the volume of the pouch 20 or imparting standing properties.

[0059] The pouches thus produced from the olefin laminate 10 of the present invention and filled with contents have excellent mono-material properties with respect to olefin resins such as polypropylene and polyethylene, and because they contain a large amount of these olefin resins, they are highly recyclable as olefin resins. Furthermore, despite containing a large amount of olefin resin, they have high impact resistance and high drop strength, effectively preventing the bag from breaking when dropped from a high place.

[0060] <Preferred embodiments of the present invention> As long as the olefin-based laminate 10 of the present invention has the above-mentioned olefin-based resin content and basic structure, various embodiments can be adopted to improve the properties required for packaging materials such as packaging bags.

[0061] For example, one or more stretched olefin-based resin layers can be laminated on the olefin-based resin layer 13 (stretched olefin-based resin layer) via a polyrotaxane-containing adhesive layer 15, thereby achieving even higher strength.

[0062] Furthermore, an inorganic coating can be provided on at least one surface of the olefin resin layer 13 (stretched olefin resin layer) or the stretched olefin resin layer laminated thereon via the adhesive layer 15, thereby improving gas barrier properties against oxygen and the like. Such inorganic coatings include vapor-deposited films of various metals or metal oxides, coating films mainly composed of silicon oxide, coating films of metal alkoxide condensates, coating films formed by a crosslinking reaction between carboxylic acid and a metal, and coating films in which metal oxides are dispersed. Furthermore, it is preferable to provide the above-mentioned coating film as a protective film (so-called top coat layer) on the above-mentioned vapor-deposited film.

[0063] The vapor-deposited film is an inorganic vapor-deposited film formed by physical vapor deposition, such as sputtering, vacuum deposition, or ion plating, or chemical vapor deposition, such as plasma CVD, and is, for example, a film formed from various metals or metal oxides. Because such a vapor-deposited film is made of an inorganic substance, it exhibits higher oxygen barrier properties than gas barrier resins such as ethylene-vinyl alcohol copolymers.

[0064] The vapor-deposited film may be formed directly on the surface of the thermoplastic resin film described above. However, in order to improve the smoothness of the vapor-deposited film and its adhesion to the film surface, it is preferable to coat the film surface with a hydrophilic resin such as polyester, polyethyleneimine, acrylic resin, polyamide, or polyurethane, and then form the vapor-deposited film on the coating film (so-called anchor coat layer).

[0065] In the present invention, from the viewpoint of ensuring that the formed film is dense and particularly high oxygen barrier properties, it is preferable that the inorganic coating be formed from a vapor-deposited film formed from silicon oxide, aluminum oxide, silica-alumina composite oxide, or the like, and it is most preferable that the inorganic coating be formed from a vapor-deposited film of silicon oxide, since this ensures particularly good transparency (haze of 5% or less) and good visibility.

[0066] It is also preferable that the above-mentioned inorganic coating film be provided on the above-mentioned vapor-deposited film as a protective film layer (topcoat layer). Such a coating film functions as a protective film that penetrates into minute defects (cracks) that occur in the above-mentioned vapor-deposited film, prevents the growth of defects, and prevents the formation of new defects. Suitable coating films include metal alkoxides such as alkoxysilanes and alkoxytitanium, and partially condensed ones are suitable in terms of adhesion to the vapor-deposited film.

[0067] The thickness of the inorganic coating described above varies depending on the level of oxygen barrier property required. In the case of a vapor deposition film, the thickness is 1 cc / m² if the properties of the thermoplastic resin film that serves as the base for vapor deposition are not impaired and if the thickness is less than 1 cc / m² before retort treatment. ２ The thickness is preferably such that an oxygen permeability of 1000 to 10 nm, particularly 100 to 10 nm, can be ensured.

[0068] The thickness and constituent elements of the inorganic coating can be identified by depth profile analysis using X-ray photoelectron spectroscopy (XPS) or Auger electron spectroscopy (AES), or energy dispersive X-ray analysis (EDX).

[0069] Furthermore, instead of the inorganic coating described above, an organic coating may be provided to ensure gas barrier properties, such as a coating film mainly made of polyvinyl alcohol or an ethylene-vinyl alcohol copolymer. The coating may be formed directly on the surface of the thermoplastic resin film described above, but in order to improve the smoothness of the coating and its adhesion to the film surface, it is preferable to coat the film surface with a hydrophilic resin such as polyester, polyethyleneimine, acrylic resin, polyamide, or polyurethane, and then form an organic coating on the coating film (so-called anchor coat layer).

[0070] Furthermore, as long as the olefin-based resin content is within the aforementioned large amount range, it is also possible to provide a layer containing a resin other than the olefin-based resin. For example, in order to suppress a decrease in puncture strength or impact resistance due to orientation relaxation of the stretched layer by heat treatment, a layer of a stretched film of a resin with a higher melting point than the olefin-based resin, such as polyamide or ethylene-vinyl alcohol copolymer, can be provided as a strength reinforcing layer. The most suitable high-melting point resin for such a strength reinforcing layer is polyamide.

[0071] The polyamide is not particularly limited and various types can be exemplified, but generally, nylon 6, nylon 6,6, nylon 11, nylon 12, nylon 13, nylon 6 / nylon 6,6 copolymer, aromatic nylon (e.g., polymetaxylylene adipamide), amorphous nylon (e.g., nylon 6I / nylon 6T), etc. are preferably used.

[0072] Furthermore, in order to satisfy the mono-material nature (large amount of olefin-based resin content) of the olefin-based laminate 10, the stretched film forming the strength reinforcement layer described above may be blended with a high-melting point resin and an olefin-based resin (e.g., a propylene-based resin) to the extent that the high strength is not impaired, or a multilayer stretched film of a stretched film of an olefin-based resin and a stretched film of a high-melting point resin may be provided as the strength reinforcement layer.

[0073] For example, in the present invention, the propylene-based resin most preferably used as the olefin-based resin is represented by an unstretched layer as CPP, an oriented layer as OPP, a polyrotaxane-containing adhesive layer as AD, an inorganic coating as INOR, and a strength-reinforcing layer as PP / Ny. The layer structure of a suitable olefin-based laminate 10 is as follows: CPP / AD / (INOR)OPP CPP / AD / (INOR)OPP / AD / OPP CPP / AD / OPP / AD / (INOR)OPP CPP / AD / (PP / Ny) / AD / (INOR)OPP Note that (INOR) means that an inorganic coating may or may not be present, and this inorganic coating may be formed on either side of the OPP. PP represents the propylene-based resin, and Ny represents nylon.

[0074] The laminate of the present invention obtained by laminating the above-mentioned layers or films may also have a printed layer laminated between the layers or on the outside of the stretched layer.

[0075] The present invention-1 will be explained in the following experimental examples. The various materials used in the following experiments are as follows.

[0076] <One Thermoplastic Resin Layer (Unstretched Sealant Film)> CPP film: Torayfan ZK500 manufactured by Toray Advanced Film Co., Ltd. Thickness: 70 μm Resin composition of film: Polypropylene (PP) component: 80% by mass, polyethylene (PE) component: 20% by mass

[0077] <Other thermoplastic resin layer> Gas barrier stretched polypropylene film with an inorganic coating formed on one side: BAOPP film Thickness: 20 μm Structure: OPP / coating film (anchor coat) / inorganic coating Inorganic coating: vapor-deposited film mainly made of silicon oxide and protective film (top coat) mainly made of silicon or silicon oxide

[0078] <Adhesive> Urethane adhesive manufactured by Toyo-Morton Co., Ltd. Main component A: polyester-based (solid component 50% by mass) Curing agent B: polyisocyanate-based (solid component 70% by mass) Main component A:curing agent B=44:4 (mass ratio).

[0079] <Polyrotaxane> Polyrotaxane-1: SeRM Super Polymer SH1300P manufactured by ASM (Advanced Soft Materials) Co., Ltd. Axial molecular weight: 11,000 Functional group modification: hydroxyl group Polyrotaxane-2: SeRM Super Polymer SH2400P manufactured by ASM Co., Ltd. Axial molecular weight: 20,000 Functional group modification: hydroxyl group

[0080] The preparation of the laminate (laminate film), bag making, and measurement of various physical properties were carried out as follows.

[0081] <Preparation of Laminate (Lamination)> An unstretched sealant film (CPP film) and a gas barrier stretched film (BAOPP film) were laminated by dry lamination to obtain a laminate. The adhesive was applied using a bar coater. The amount of adhesive applied was approximately 3 to 3.5 g / m2 in terms of solid content. ２ The CPP film was laminated so that it faced the inorganic coating of the BAOPP film. After lamination, the film was cured at 50°C for 4 to 5 days.

[0082] <Bag Manufacturing> Two pieces of 140 mm x 180 mm were cut out of the laminate (laminate film) obtained above, and filled with 200 g of water to form pouches. Sealing was performed using an impulse sealer manufactured by Fuji Impulse Co., Ltd. under the following conditions: Sealing conditions: 185°C, 1.4 (s) Sealing width: approximately 5 mm

[0083] <Pouch Drop Strength> Two pouches, cooled overnight at 5°C, were dropped horizontally from a height of 120 cm to measure the drop strength. The bottom pouch was used as the test pouch. The number of tests (N) was set to 3 or more, and the average number of unbroken pouches was measured.

[0084] <Dynamic viscoelasticity of adhesive coating film> A dynamic viscoelasticity measuring device manufactured by Seiko Instruments Inc. was used. The test conditions were as follows: Test piece film: length 20 mm, width 10 mm Distance between chucks: 5 mm Temperature range: -20°C to 40°C Heating rate: 2°C / min Frequency: 10 Hz Tan δ (loss tangent): Calculated by dividing the loss modulus at 5°C (E'') by the storage modulus (E'). E' (storage modulus): Calculated as the value at 5°C.

[0085] <Amount of Olefin-Based Resin Per Total Amount of Laminate> The amount of olefin-based resin (mass %) was calculated using the following formula.

[0086] In the above formula, the adhesive is applied in an amount of 3.25 g / m ２ , thickness is 3.5 μm, density is 0.93 g / cm ３ The calculation is based on the assumption that polypropylene (PP) has a density of 0.90 g / cm ３ The calculation is made assuming that polyethylene (PE) has a density of 0.93 g / cm ３ The calculation is made assuming that:

[0087] Example 1 A urethane adhesive (44 g of base agent A, 4 g of curing agent B) was mixed with polyrotaxane-1 (0.48 g) to prepare an adhesive containing 1.9% by mass of polyrotaxane-1 relative to the total solid components of base agent A, curing agent B, and polyrotaxane-1. The dynamic viscoelasticity of the adhesive coating was evaluated, and the results are shown in Table 1. (As explained above, the coating amount of this adhesive was approximately 3 to 3.5 g / m2 in terms of solid components.) ２ It is adjusted with ethyl acetate so that

[0088] Next, the adhesive was applied to a CPP film, and a BAOPP film was laminated on top of this using a dry lamination method to obtain a laminate. The laminate was cured at 50°C for 4 days, and then pouches (filled with 200g of water) were made using this laminate, and the drop strength was evaluated. The olefin resin content per total laminate was also calculated. The results are shown in Table 2.

[0089] Example 2 An adhesive (polyrotaxane-1 content: 5.6% by mass) was prepared in the same manner as in Example 1, except that the amount of polyrotaxane-1 was increased to 1.48 g, and the dynamic viscoelasticity of the adhesive coating was evaluated. Furthermore, a laminate and a pouch were produced in the same manner as in Example 1, except that this adhesive was used, and various properties were evaluated. The results are shown in Tables 1 and 2.

[0090] Example 3 Except for using polyrotaxane-2 instead of polyrotaxane-1, an adhesive was prepared, a laminate and a pouch were produced, and various properties were evaluated in the same manner as in Example 1. The results are shown in Tables 1 and 2.

[0091] Example 4 Except for changing polyrotaxane-1 to polyrotaxane-2, an adhesive was prepared, a laminate and a pouch were made, and various properties were evaluated in the same manner as in Example 2. The results are shown in Tables 1 and 2.

[0092] Comparative Example 1 An adhesive (polyrotaxane content 0% by mass) was prepared in the same manner as in Example 1, except that polyrotaxane-1 was not used, and a laminate and a pouch were produced in the same manner as in Example 1, except that this adhesive was used, and various properties were evaluated. The results are shown in Table 2.

[0093] In Tables 1 and 2, adhesives are indicated by AD, polyrotaxane-1 is indicated by PR1, and polyrotaxane-2 is indicated by PR2. AD(PR1) means that polyrotaxane-1 is blended into a urethane adhesive, and AD(PR2) means that polyrotaxane-2 is blended into a urethane adhesive. PO represents an olefin resin.

[0094]

[0095]

[0096] Reference Example An adhesive containing 17.7% by mass of polyrotaxane-1 or polyrotaxane-2 was prepared in the same manner as in Example 1 or Example 3, except that the amount of polyrotaxane-1 or polyrotaxane-2 added was increased to 5.33 g, and pouches were fabricated and subjected to a bag drop test in the same manner as in Example 1 or Example 3. As a result, the number of unbroken pouches was not significantly different from that of Comparative Example 1, in which no polyrotaxane was added, and it was found that the optimal polyrotaxane content in the adhesive was less than 17% by mass.

[0097] The present invention-2 will be explained in the following experimental examples. The materials used in the following experiments are as follows: <Sealant polyethylene film> A linear low-density polyethylene film having a thickness of 150 μm was used.

[0098] <Polyethylene Film Substrate> A biaxially oriented polyethylene film having a thickness of 25 μm was used.

[0099] <Adhesive> Urethane adhesive manufactured by Toyo-Morton Co., Ltd. Main component C: polyester-based (solid component 60% by mass) Curing agent D: polyisocyanate-based (solid component 52.5% by mass) Main component C:curing agent D = 18:4 (mass ratio).

[0100] <Polyrotaxane> Polyrotaxane-1: SeRM Super Polymer SH1300P manufactured by ASM (Advanced Soft Materials) Co., Ltd. Axial molecular weight: 11,000 Functional group modification: hydroxyl group

[0101] The preparation of the laminate (laminate film), bag making, and measurement of various physical properties were carried out as follows.

[0102] <Preparation of Laminate (Lamination)> A sealant polyethylene film and a biaxially oriented polyethylene film were laminated by dry lamination to obtain a laminate. The adhesive was applied using a bar coater. The amount of adhesive applied was approximately 3 to 3.5 g / m2 in solid content. ２ After lamination, the film was cured at 50°C for 4 to 5 days.

[0103] <Bag Manufacturing> The laminate (laminate film) obtained above was made into a bag measuring 130 mm in width, 175 mm in height, and 36 mm in width when the base material was folded, and 330 g of water was filled into the bag. Sealing was performed using a thermal plate heat sealer under the following conditions: Sealing conditions: top surface heating 200°C, 1.0 (s), 0.3 MPa, sealing width: approximately 5 mm

[0104] <Pouch Drop Strength> A pouch cooled overnight at 5°C was dropped vertically from a height of 150 cm to measure the drop strength.

[0105] Example 5 A urethane adhesive (main component C: 18 g, curing agent D: 4 g) was mixed with polyrotaxane-1 (0.26 g) to prepare an adhesive containing 2.0 mass % of polyrotaxane-1 relative to the total solid components of main component A, curing agent B, and polyrotaxane-1. (As explained above, the coating amount of this adhesive was approximately 3 to 3.5 g / m2 in terms of solid components.) ２ It is adjusted with ethyl acetate so that

[0106] Next, the adhesive was applied to a biaxially oriented polyethylene film (BAOPE), and a sealant polyethylene film (LLDPE) was laminated thereon by a dry lamination method to obtain a laminate. The laminate was cured at 50°C for 4 days, and then a pouch (filled with 330 g of water) was made using the laminate, and the dropping strength was evaluated.

[0107] Comparative Example 2 An adhesive (polyrotaxane content 0% by mass) was prepared in the same manner as in Example 5, except that polyrotaxane-1 was not used, and a laminate and a pouch were produced in the same manner as in Example 1, except that this adhesive was used, and various properties were evaluated. The results are shown in Table 3.

[0108]

[0109] 1: Polyrotaxane 2: Axial molecule 3: Cyclic molecule 4: Terminal group 5: Side chain 10: Olefin-based laminate 11: Thermoplastic resin layer 13: Thermoplastic resin layer 15: Adhesive layer 20: Pouch

Claims

1. A laminate having a layer structure in which an adhesive layer is provided between two thermoplastic resin layers, wherein the adhesive layer is formed from an adhesive containing polyrotaxane, and in the laminate, an olefin resin is contained in an amount of 80% by mass or more based on the total amount of the laminate.

2. The laminate according to claim 1, wherein the olefin resin is an ethylene resin or a propylene resin.

3. The laminate according to claim 1, wherein the olefin resin is a resin composition containing an ethylene resin and a propylene resin.

4. The laminate according to claim 1, wherein in the adhesive layer, polyrotaxane is blended in an amount of less than 17% by mass.

5. The laminate according to claim 1, wherein in the adhesive layer, polyrotaxane is blended in a urethane-based adhesive.

6. The laminate according to claim 1, wherein in the polyrotaxane, the functional group at the end of the cyclic molecular side chain is a hydroxyl group.

7. The laminate according to claim 1, wherein among the two thermoplastic resin layers, one thermoplastic resin layer is an unstretched sealant film made of the olefin resin, and the other thermoplastic resin layer is formed from an unstretched or stretched film.

8. The laminate according to claim 7, wherein the other thermoplastic resin layer is formed of a stretched film, and an inorganic film or an organic film is provided on the stretched film.

9. The laminate according to claim 7, wherein an intermediate thermoplastic resin layer is provided between the one thermoplastic resin layer and the other thermoplastic resin layer.

10. The laminate according to claim 9, wherein the other thermoplastic resin layer is a stretched film, the intermediate thermoplastic resin layer is an unstretched or stretched film, and at least one of the other thermoplastic resin layer or the intermediate thermoplastic resin layer is made of the olefin resin.

11. The laminate according to claim 10, wherein an inorganic film or an organic film is provided on at least one of the stretched film forming the other thermoplastic resin layer or the stretched film forming the intermediate thermoplastic resin layer.

12. A pouch obtained from the laminate according to claim 1.