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

[Technical Field]

[0001] The present invention relates to a laminate, and more particularly to an olefin-based laminate containing a large amount of olefin resin, which is suitable for manufacturing pouches by heat sealing or ultrasonic sealing. [Background technology]

[0002] Olefin resins, such as propylene resins and ethylene resins, have been used in the packaging field for a long time, and pouches with unstretched olefin resin films as a sealant resin layer are widely manufactured, especially because they are easy to heat seal.

[0003] Furthermore, since packaging materials such as pouches require strength characteristics such as puncture resistance, the unstretched olefin resin films described above are used in the form of laminates in which reinforcing films such as stretched films are laminated. In such laminates, the reinforcing film is laminated to the unstretched olefin resin film using a dry laminating adhesive or the like.

[0004] Incidentally, in recent years, the recyclability of materials has become a requirement from an environmental perspective. Therefore, in laminates using unstretched olefin resins, it is necessary to maximize the olefin resin content and eliminate as many other materials as possible to create a monomaterial structure. This is because a highly monomaterial laminate containing a large amount of olefin resin can be reused as olefin resin again.

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

[0006] In recent years, polymers with a molecular structure called polyrotaxanes have been developed. These polymers are complex molecules in which a chain-like axial molecule penetrates the rings of multiple cyclic molecules, and bulky groups are bonded to both ends of the axial molecule. This steric hindrance prevents the cyclic molecules from detaching from the axial molecule. Such complexes are called supramolecules. Various applications have been proposed for these polyrotaxanes.

[0007] For example, Patent Document 1 proposes a laminate for vacuum insulation in which a heat-sealable layer and a gas barrier layer are bonded together with a polyrotaxane-containing adhesive. In such a laminate, because polyrotaxane is incorporated into the adhesive, the adhesive follows the expansion and contraction of each layer, resulting in no delamination between layers and excellent gas barrier properties.

[0008] Furthermore, Patent Document 2 proposes a cell packaging material having an outer layer made of polyrotaxane. In this cell packaging material, the outer layer is made of polyrotaxane instead of PET or Ny, which improves abrasion resistance and scratch resistance.

[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 manufacture molded articles with excellent elongation and strength.

[0010] As described above, various applications for polyrotaxanes have been proposed, but their incorporation into adhesives for highly monomaterial laminates containing a large amount of olefin resin has not been considered at all. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2021-1650 [Patent Document 2] Patent No. 6153183 [Patent Document 3] Patent No. 6655555 [Overview of the project] [Problems that the invention aims to solve]

[0012] Therefore, the 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 creating pouches with excellent impact resistance and drop strength. Another object of the present invention is to provide an olefin-based laminate mainly composed of an olefin resin obtained by using an adhesive containing polyrotaxane. [Means for solving the problem]

[0013] According to the present invention, a laminate having a layer structure in which an adhesive layer is provided between two thermoplastic resin layers, The aforementioned adhesive layer is formed from an adhesive containing polyrotaxane. The provided laminate is characterized in that, in the laminate, olefin resin is contained in an amount of 80% by mass or more of the total amount of the laminate.

[0014] In the laminate of the present invention (hereinafter referred to as the olefin-based laminate), the following embodiments are preferably adopted. (1) The olefin resin is an ethylene resin or a propylene resin. (2) The olefin resin is a resin composition containing an ethylene resin and a propylene resin. (3) The adhesive layer contains polyrotaxane in an amount of less than 17% by mass. (4) The adhesive layer contains polyrotaxane in the urethane adhesive. (5) In the polyrotaxane, the functional group at the end of the cyclic molecular side chain is a hydroxyl group. (6) 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. (7) 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. (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 or the intermediate thermoplastic resin layer is made of the olefin resin. (10) 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.

[0015] According to the present invention, there is also provided a pouch obtained from the above olefin-based laminate.

Effect of the Invention

[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 resin in an amount of 80% by mass or more based on the total mass of the laminate. Therefore, the monomer material property of the olefin resin is high and the recyclability is excellent.

[0017] Further, in the present invention, although a small amount of a material other than the olefin resin is used on the condition that the olefin resin content is within the above range, an adhesive containing polyrotaxane is particularly used. As a result, the pouch (bag-like container) formed of this laminate shows high bag-drop strength while being mostly formed of the olefin resin, and effectively prevents bag breakage due to dropping 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 range of satisfying the basic structure described above. [Brief explanation of the drawing]

[0019] [Figure 1] A diagram illustrating the molecular structure of the polyrotaxane used in this invention. [Figure 2] A diagram showing the basic layer structure of the olefin-based laminate of the present invention. [Figure 3] Figure 2 shows the cross-sectional structure of the pouch obtained from the laminate. [Modes for carrying out the invention]

[0020] <Polyrotaxane> First, we will explain the polyrotaxane incorporated into the adhesive layer in this invention. Polyrotaxanes are known compounds, and as shown in Figure 1, the polyrotaxane molecule represented as 1 has a complex molecular structure formed from a chain-like axial molecule 2 and a cyclic molecule 3. That is, multiple cyclic molecules 3 enclose the chain-like axial molecule 2, and the axial molecule 2 penetrates the inside of the rings of the cyclic molecules 3. Therefore, the cyclic molecules 3 can slide freely on the axial molecule 2, but bulky terminal groups 4 are formed at both ends of the axial molecule 2, preventing the cyclic molecules 3 from detaching from the axial molecule 2.

[0021] In other words, because the cyclic molecule 3 can slide on the axial molecule 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 distribute stress when a load is applied. This is a factor that improves impact resistance.

[0022] In such polyrotaxanes, various types of chain-like axial molecules 2 are known. For example, they can be linear or branched, as long as they can penetrate the rings of the cyclic molecule, and are generally formed from polymers.

[0023] Polymers that form such axis molecules 2 include polyvinyl alcohol, polyvinylpyrrolidone, cellulose resins (carboxymethylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, etc.), polyacrylamide, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinyl acetal, polyvinyl methyl ether, polyamine, polyethyleneimine, casein, gelatin, starch, olefin resins (polyethylene, polypropylene, etc.), polyester, polyvinyl chloride, styrene resins (polystyrene, acrylonitrile-styrene copolymer resin, etc.), acrylic resins (poly(meth)acrylic acid, Examples of polymers 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, polydiene (polyisoprene, polybutadiene, etc.), polysiloxane (polydimethylsiloxane, etc.), polysulfone, polyimine, polyacetic anhydride, polyurea, polysulfide, polyphosphazene, polyketone, polyphenylene, and polyhaloolefin. These polymers may be copolymerized or modified as appropriate.

[0024] In the present invention, suitable polymers for forming the axis molecule 2 are polyethylene glycol, polyisoprene, polyisobutylene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, polypropylene, polyvinyl alcohol, or polyvinyl methyl ether. Polyethylene glycol is the most suitable in terms of affinity and reactivity with adhesives containing polyrotaxane. Polyethylene and polypropylene are also suitable in terms of monomaterial properties.

[0025] Furthermore, the bulky terminal groups 4 formed at both ends of the axial molecule 2 include adamantyl group, trityl group, fluoresceinyl group, dinitrophenyl group, and pyrenyl group. base Among the various options, the adamantyl group is particularly preferred due to its ease of introduction.

[0026] While the molecular weight of the axial molecule described above is not particularly limited, if it is too large, the affinity with the adhesive component tends to decrease, and if it is too small, the mobility of the cyclic molecule decreases, which tends to reduce the impact resistance improvement effect. From this perspective, the weight-average molecular weight Mw of axial molecule 2 is preferably in the range of approximately 1,000 to 100,000.

[0027] The cyclic molecule 3 can have any ring that is large enough to enclose the axial molecule 2. Examples of such rings include a cyclodextrin ring, a crown ether ring, a benzocrown ring, a dibenzocrown ring, and a dicyclohexanocrown ring, with a cyclodextrin ring being particularly preferred.

[0028] As described above, multiple cyclic molecules 3 are encapsulated within a single axial molecule 2. Generally, when the maximum number of cyclic molecules that can be encapsulated per axial molecule is defined as 1, the number of cyclic molecules 3 encapsulated 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 number of cyclic molecules 3 encapsulated is too large, the cyclic molecules 3 are densely packed around a single axial molecule, which reduces its mobility and tends to decrease the impact resistance improvement effect. Conversely, if the number of cyclic molecules 3 encapsulated is too small, the gaps between the axial molecules 2 become narrower, which also reduces mobility and tends to decrease the impact resistance improvement effect.

[0029] Furthermore, the maximum number of cyclic molecules 3 that can be inclusioned by a single axial molecule 2 can be calculated from the length of the axial molecule 2 and the thickness of the rings of the cyclic molecule 3. For example, if the axial molecule 2 is formed of polyethylene glycol and the ring of the cyclic molecule 3 is an α-cyclodextrin ring, the maximum number of inclusions can be calculated as follows. In other words, two repeating units [-CH2-CH2O-] of polyethylene glycol approximate the thickness of one α-cyclodextrin ring. Therefore, the number of repeating units can be calculated from the molecular weight of polyethylene glycol, and half of this number of repeating units can be determined as the maximum number of inclusions for the cyclic molecule. This maximum number of inclusions is set to 1.0, and the number of inclusions for the cyclic molecule is adjusted to the aforementioned range.

[0030] Furthermore, in the present invention, the ring of the cyclic molecule 3 described above may have a side chain introduced into it. This side chain is shown as 5 in Figure 1. In other words, by introducing such side chains 5 into the ring, an appropriate space can be more reliably formed between adjacent axial molecules 2, which is advantageous for improving impact resistance. Furthermore, the introduction of side chains 5 imparts reactivity to the adhesive component containing polyrotaxane, forming a cross-linked structure with the adhesive, thereby further improving the strength when the pouch is formed.

[0031] The side chain 5 described above is preferably formed by repeating organic chains with 3 to 20 carbon atoms, and the average weight molecular weight of such a side chain is approximately 300 to 10000.

[0032] The side chain 5 described above is introduced by utilizing the functional groups of the ring possessed by the cyclic molecule 3 and modifying these functional groups. For example, the α-cyclodextrin ring has 18 hydroxyl groups as functional groups, and side chains are introduced via these hydroxyl groups. That is, a maximum of 18 side chains can be introduced to a single α-cyclodextrin ring. For example, if side chains are attached to 9 of the 18 hydroxyl groups of the α-cyclodextrin ring, the degree of modification is 50%. Such a degree of modification is set to an appropriate range depending on the adhesive component used in combination.

[0033] In the present invention, the side chain 5 (organic chain) described above may be linear or branched, as long as the polyrotaxane property of the cyclic molecule 3 sliding on the axis molecule 2 is not impaired. A side chain of 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, etc.

[0034] For example, ring-opening polymerization can introduce side chains derived from cyclic compounds such as cyclic lactones, cyclic ethers, cyclic acetals, cyclic amines, cyclic carbonates, cyclic iminoethers, and cyclic thiocarbonates. Among these, cyclic ethers, cyclic siloxanes, lactones, and cyclic carbonates are preferred because they are readily available, highly reactive, and their size (molecular weight) can be easily adjusted.

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

[0036] Furthermore, as radical polymerizable compounds used to introduce side chains by radical polymerization, compounds having at least one functional group having an ethylenically unsaturated bond, such as a (meth)acrylic group, vinyl group, or styryl group (hereinafter referred to as ethylenically unsaturated monomers), are preferably used.

[0037] As can be understood from the above explanation, the side chain 5 introduced into the ring of cyclic molecule 3 may have repeating units such as -O-bonds, -NH-bonds, or -S-bonds, depending on the method of introduction, or it may have substituents such as hydroxyl groups, carboxyl groups, acyl groups, phenyl groups, halogen atoms, silyl groups, mercapto groups, vinyl groups, NCO groups, NCS groups, etc. Furthermore, depending on the type of functional group present in the compound used to introduce side chain 5, a portion of this side chain may bond to a functional group on the ring of a cyclic molecule present in another axial molecule, forming a pseudo-crosslink structure.

[0038] In the present invention, the most preferably used polyrotaxane 1 has polyethylene glycol as the core molecule 2, to which an adamantyl group is bonded as terminal group 4, and the cyclic molecule 3 has a cyclic molecule 3 having an α-cyclodextrin ring, and further has a side chain 5 (terminally OH group) such as polycaprolactone introduced.

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

[0040] In other words, because the laminate 10 of the present invention contains a very large amount of olefin resin, it has high monomaterial properties and excellent recyclability. For example, if it is collected as waste after use, it can be reused as an olefin resin, either alone or mixed with virgin olefin resin, after being crushed, washed, and dried as appropriate, thereby suppressing the deterioration of physical properties due to recycled use.

[0041] Thermoplastic resin layer 11,13; figure 2 In this process, olefin resins are typically used to form the thermoplastic resin layers 11 and 13 in order to achieve the aforementioned olefin resin content. Examples of these olefin resins 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] Furthermore, the olefin resin may be a resin composition containing an ethylene resin and a propylene resin, or the thermoplastic resin layer 11 may be formed from an ethylene resin or a propylene resin, and the thermoplastic resin layer 13 may be formed from a propylene resin or an ethylene resin. However, in order to enhance monomateriality and obtain the form most suitable for recyclability, it is preferable to form the thermoplastic resin layers 11 and 13 using the same olefin resin.

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

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

[0045] adhesive layer 15; In the olefin-based laminate 10 described above, the adhesive layer 15 is formed of an adhesive containing the polyrotaxane mentioned earlier. That is, because one olefin-based resin layer 11 (unstretched film) and the other olefin-based resin layer 13 (stretched film) are bonded together by such an adhesive, a pouch 20 with excellent heat resistance and impact resistance can be obtained. Furthermore, the adhesive layer 15 only needs to be located between the thermoplastic resin layers 11 and 13, and does not necessarily need to be adjacent to these resin layers 11 and 13.

[0046] The adhesive containing polyrotaxane is not particularly limited, and dry laminating adhesives such as urethane-based adhesives and epoxy-based adhesives can be used. However, to make the most of the properties of polyrotaxane, it is preferable to use a urethane-based adhesive.

[0047] In particular, urethane adhesives are effective when an epoxy group, episulfide group, thietanyl group, OH group, SH group, NH2 group, NCO group, or NCS group is introduced as a functional group to the side chain 5 of the polyrotaxane. For example, polyurethane is formed by the reaction of a polyol and a polyisocyanate. That is, when the above functional groups are introduced to the side chain 5 of the polyrotaxane, the side chain 5 of the polyrotaxane is incorporated into the polymerization chain of the polyurethane formed by the reaction of the polyol and the polyisocyanate, forming a crosslinked structure, which is most suitable for improving the strength of the pouch.

[0048] Polyols used in the formation of polyurethane adhesives are compounds having two or more OH groups in one molecule. Examples include di-, tri-, tetra-, penta-, and hexa-hydroxy compounds, polyesters containing two or more OH groups in one molecule (polyester polyols), polyethers containing two or more OH groups in one molecule (hereinafter referred to as polyether polyols), polycarbonates containing two or more OH groups in one molecule (polycarbonate polyols), polycaprolactones containing two or more OH groups in one molecule (polycaprolactone polyols), and acrylic polymers containing two or more OH groups in one molecule (polyacrylic polyols). In the present invention, the most suitable polyol is polyester polyol due to its high affinity with polyrotaxanes.

[0049] The polyester polyols described above are polymers obtained by the condensation reaction of polyols with polybasic acids such as adipic acid and phthalic acid. Examples of polyols that react with polybasic acids 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] Furthermore, polyisocyanates that react with polyols are compounds having two or more NCO groups in one molecule. Specific examples, though not limited to these, include: aliphatic isocyanates such as ethylene diisocyanate, trimethylene diisocyanate, and tetramethylene diisocyanate; alicyclic isocyanates such as isophorone diisocyanate, norbornane diisocyanate, bis(isocyanate methyl)cyclohexane, 2-isocyanate methyl-3-(3-isocyanate propyl)-5-isocyanate methyl-bicyclo[2,2,1]-heptane; aromatic isocyanates such as xylylene diisocyanate, bis(isocyanate ethyl)benzene, bis(isocyanate methyl)naphthalene, and bis(isocyanate methyl)diphenyl ether; sulfur-containing aliphatic isocyanates such as thiodiethyl diisocyanate; and bis[2-(isocyanate methyl Examples include aliphatic sulfide isocyanates such as lutio(ethyl) sulfide; aromatic sulfide isocyanates such as diphenyl sulfide-2,4'-diisocyanate; 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 benzulfonyl-4'-isocyanate phenol ester; aromatic sulfonic acid amide isocyanates such as 4-methyl-3-isocyanate benzulfonylanilide-3'-methyl-4'-isocyanate; and sulfur-containing heterocyclic isocyanates such as thiophene-2,5-diisocyanate.

[0051] The polyisocyanates mentioned above are typically used in amounts such that the isocyanate groups (NCO groups) are approximately 0.8 to 1.2 moles per mole of hydroxyl groups present in the aforementioned polyol.

[0052] In the present invention, it is preferable that the polyrotaxane is 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 distribution effect due to the sliding of the cyclic molecules 3 of the polyrotaxane is fully exhibited, for example, impact resistance is improved, and bag rupture due to dropping when the pouch 20 is formed is effectively suppressed.

[0053] As confirmed in the examples described later, adhesive coatings containing polyrotaxane in the amounts described above exhibit improved loss tangent (tanδ) and vibration absorption in dynamic viscoelasticity tests (10 Hz) at 5°C. For example, in Examples 1 to 4 described later, polyrotaxane is added to the urethane adhesive. Such polyrotaxane-containing adhesive coatings show a loss tangent (tanδ) of 0.21 or higher, particularly 0.23 or higher, in a dynamic viscoelasticity test (10 Hz) at 5°C, indicating improved vibration absorption.

[0054] Furthermore, adhesive coatings containing polyrotaxane in the above-mentioned amounts, which have improved vibration absorption, preferably have an elastic modulus equivalent to that of adhesive coatings without polyrotaxane in order to firmly bond the films together. However, as shown in the results of the examples described later, the adhesive coatings of Examples 1 to 4, like Comparative Example 1 which uses an adhesive coating without polyrotaxane, have a storage modulus E' exceeding 1 GPa in a dynamic viscoelasticity test (10 Hz) at 5°C.

[0055] In the present invention, an adhesive containing the polyrotaxane described above is made available for use by adding the polyrotaxane to a reactive component that forms the adhesive (for example, a coating composition in which a polyester polyol and a polyisocyanate are dispersed in an organic solvent). Specifically, the polyrotaxane-containing coating composition is applied to a film that forms one olefin resin layer, then the film that forms the other olefin resin layer is pressed onto it, and the mixture is heated to an appropriate temperature to perform polymerization curing and solvent removal, thereby forming an adhesive layer 15, and an olefin laminate 10 shown in Figure 2 is formed in which the thermoplastic resin layer 11 and the thermoplastic resin layer 13 are bonded by the adhesive layer 15.

[0056] In such a laminate 10, the thickness of the adhesive layer 15 is very thin, and naturally, it is within the range that satisfies the aforementioned olefin resin content in the laminate 10. For example, generally, it is 2-5 g / m 2 It is of a certain thickness.

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

[0058] The pouch is made by known means. For example, an empty pouch is made by a three-sided seal using two olefin laminates 10,10, the contents are filled in from the opening, and finally the opening is closed by heat sealing. Furthermore, an empty pouch can also be made by folding a single olefin laminate 10 and heat-sealing both ends. In this case, it is not necessary to heat-seal the bottom. In addition, an empty pouch can also be manufactured using olefin laminate 10 specifically for the sides or bottom. Such methods are advantageous in increasing the volume of the pouch 20 or in providing standing ability.

[0059] In this way, pouches made from the olefin-based laminate 10 of the present invention and filled with contents exhibit excellent monomaterial properties with respect to olefin-based resins such as polypropylene and polyethylene, and because they contain a large amount of these olefin-based resins, they have excellent recyclability as olefin-based resins. Furthermore, despite containing a large amount of olefin-based resin, they also have high impact resistance and high drop strength, effectively suppressing bag rupture due to drops from heights.

[0060] <Preferred aspects of the present invention> As long as the olefin-based laminate 10 of the present invention has the above-described 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 resin layers can be laminated onto an olefin resin layer 13 (a stretched olefin resin layer) via a polyrotaxane-containing adhesive layer 15, thereby achieving 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 an adhesive layer 15 to improve gas barrier properties against oxygen and other elements. 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 crosslinking reactions between carboxylic acids and metals, and coating films in which metal oxides are dispersed. In addition, it is preferable to provide the above-mentioned coating film as a protective film (so-called topcoat layer) on the vapor-deposited film.

[0063] The above-mentioned vapor-deposited films are inorganic films formed by physical vapor deposition methods such as sputtering, vacuum deposition, and ion plating, or by chemical vapor deposition methods such as plasma CVD. For example, they are films formed from various metals or metal oxides. Because such vapor-deposited films are made of inorganic materials, they exhibit higher oxygen barrier properties compared to gas barrier resins such as ethylene-vinyl alcohol copolymers.

[0064] Furthermore, while the vapor deposition film formation described above may be performed directly on the surface of the thermoplastic resin film, 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 deposition film on the coating film (so-called anchor coat layer) in order to improve the smoothness of the vapor deposition film and its adhesion to the film surface.

[0065] In this invention, the formed film is dense, and in particular, from the viewpoint of ensuring high oxygen barrier properties, the vapor-deposited film is made of silicon oxide, aluminum oxide, silica-alumina composite oxide, etc. covered It is preferable that a film is formed, and in particular, transparency is ensured (haze of 5% or less), and good visibility is observed, so a silicon oxide vapor-deposited film is used for inorganic systems covered It is most preferable that a film is formed.

[0066] Furthermore, it is preferable that the aforementioned inorganic coating film is provided on the vapor-deposited film as a protective film layer (topcoat layer). Such a coating film penetrates into the fine defects (cracks) that form in the vapor-deposited film, preventing the growth of defects and functioning as a protective film that prevents the formation of new defects. Suitable coating films for this purpose include those containing metal alkoxides such as alkoxysilanes and alkoxytitaniums, and in which a portion is condensed, as these are preferable in terms of adhesion to the vapor-deposited film.

[0067] The inorganic systems mentioned above coveredThe film thickness varies depending on the required level of oxygen barrier properties, but in the case of vapor-deposited films, the thickness should be 1 cc / m² before retort processing, provided that the properties of the thermoplastic resin film used as the base during deposition are not impaired. 2 / day / a tm It is best to use a thickness that ensures the following oxygen permeability, and generally, 1 0~ 10 00 nm, especially 1 0~ 10 0 A thickness of approximately nm is sufficient.

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

[0069] Furthermore, instead of the inorganic coating mentioned above, an organic coating may be provided to ensure gas barrier properties, such as a coating film mainly composed of polyvinyl alcohol or ethylene-vinyl alcohol copolymer. In addition, the coating may be formed directly on the surface of the thermoplastic resin film as described above, but in order to improve the smoothness of the coating and 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 organic coating on the coating film (so-called anchor coat layer).

[0070] Furthermore, as long as the olefin resin content remains within the aforementioned high-amount range, it is also possible to provide layers containing resins other than olefin resins. For example, to suppress the decrease in impact resistance due to puncture strength or relaxation of the orientation of the stretched layer due to heat treatment, a layer of stretched film made of a resin with a higher melting point than olefin resins, 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 polyamides mentioned above are not particularly limited, and various examples can be given, 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 preferred.

[0072] Furthermore, in order to satisfy the monomaterial properties (high olefin resin content) of the olefin laminate 10, the stretched film may be blended with a high-melting-point resin and an olefin resin (e.g., a propylene resin) to the extent that it does not impair the high strength, or a multilayer stretched film of a stretched olefin resin and a stretched high-melting-point resin may be provided as the strength-reinforcing layer.

[0073] For example, in the present invention, the unstretched layer of the propylene resin most preferably used as an olefin resin is represented as CPP, the stretched layer as OPP, the polyrotaxane-containing adhesive layer as AD, the inorganic coating as INOR, and the strength-reinforcing layer as PP / Ny. The layer structure of the preferred olefin 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 Furthermore, (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. Furthermore, PP refers to propylene resin, and Ny refers to nylon.

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

[0075] Invention 1 will be explained with the following experimental example. The materials used in the following experiment are as follows:

[0076] <One side: Thermoplastic resin layer (unstretched sealant film)> CPP film: Toray Film Processing Co., Ltd. Trefan ZK500 Thickness: 70 μm The resin composition of the film; Polypropylene (PP) content: 80% by mass Polyethylene (PE) component: 20% by mass

[0077] <The other thermoplastic resin layer> Inorganic material on one side covered Gas barrier stretched polypropylene film with a film formed on it: BAOPP film Thickness: 20 μm Composition: OPP / Coating film (anchor coat) / Inorganic coating Inorganic covered Film: Deposited film mainly composed of silicon oxide and silicon or A protective film (topcoat) primarily composed of silicon oxide.

[0078] <Adhesive> Urethane adhesive Manufactured by Toyo Morton Co., Ltd. Main component A: Polyester-based (50% by mass of solid components) Hardener B; Polyisocyanate-based (70% by mass of solid components) The ratio of main component A to hardener B was set to 44:4 (by mass).

[0079] <Polyrotaxane> Polyrotaxane-1 Manufactured by ASM (Advanced Soft Materials) Co., Ltd. SeRM Super Polymer SH1300P Axial molecular weight; 11000 Modified functional groups; hydroxyl groups Polyrotaxane-2 SeRM Super Polymer SH2400P, manufactured by ASM Corporation. Axial molecular weight; 20000 Modified functional groups; hydroxyl groups

[0080] The preparation of the laminated material (laminate film), the fabrication of bags, and the measurement of various physical properties were carried out as follows.

[0081] <Laminate fabrication (lamination)> A laminate was obtained by laminating an unstretched sealant film (CPP film) and a gas barrier stretched film (BAOPP film) using the dry lamination method. The adhesive was applied using a bar coater. The application amount was approximately 3-3.5 g / m² of solid components. 2 The mixture was adjusted with ethyl acetate to achieve the desired result. Furthermore, the CPP film was laminated so that it faced the inorganic coating of the BAOPP film. After lamination, the material was cured at 50°C for 4-5 days.

[0082] <Bag making> Two sheets of the laminated material (laminate film) obtained above were cut to 140mm x 180mm, filled with 200g of water, and formed into pouches. The sealing was performed using an impulse sealer manufactured by Fuji Impulse Co., Ltd. under the following conditions. Sealing conditions: 185°C, 1.4(s) Seal width: Approximately 5mm

[0083] <Pouch drop strength> Pouches cooled overnight at 5°C were dropped horizontally from a height of 120 cm in stacks of two pouches for measurement. The bottom pouch was designated as the test pouch. The average number of unbroken pouches was measured, with N (number of tests) ≥ 3.

[0084] <Dynamic viscoelasticity of adhesive coatings> A dynamic viscoelasticity measuring device manufactured by Seiko Instruments Inc. was used. The test conditions were as follows: Test film: Length 20mm, width 10mm Chuck spacing: 5mm Temperature range: -20℃ to 40℃ Heating rate: 2°C / min Frequency: 10Hz tanδ(loss tangent): It was calculated as the loss modulus (E'') / storage modulus (E') at 5°C. E' (storage modulus): Calculated using the value at 5°C.

[0085] <Amount of olefin resin per total laminated mass> The amount of olefin resin (mass%) was calculated using the following formula.

number

[0086] In the above formula, the adhesive is applied at a rate of 3.25 g / m². 2 Assuming a thickness of 3.5 μm, the density is 0.93 g / cm³. 3 We will perform the calculation assuming this. Polypropylene (PP) has a density of 0.90 g / cm³. 3 We will perform the calculations assuming the following. Also, the density of polyethylene (PE) is 0.93 g / cm³. 3 We will perform the calculation assuming this.

[0087] <Example 1> A urethane-based adhesive (main component A 44g, hardener B 4g) and polyrotaxane-1 (0.48g) were mixed to create an adhesive containing 1.9% by mass of polyrotaxane-1 relative to the solid component of main component A, hardener B, and polyrotaxane-1 combined. The dynamic viscoelasticity of the adhesive coating was evaluated and is shown in Table 1. (As explained earlier, the application amount of this adhesive is approximately 3-3.5g / m² of the solid component.) 2 It is prepared with ethyl acetate to achieve this.

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

[0089] <Example 2> An adhesive (containing 5.6% by mass of polyrotaxane-1) 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. Laminates and pouches were then manufactured 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> The adhesive was prepared in the same manner as in Example 1, except that polyrotaxane-2 was used instead of polyrotaxane-1. Laminates and pouches were then fabricated, and various properties were evaluated. The results are shown in Tables 1 and 2.

[0091] <Example 4> The adhesive was prepared in the same manner as in Example 2, except that polyrotaxane-1 was replaced with polyrotaxane-2. Laminates and pouches were then fabricated, and their various properties were evaluated. The results are shown in Tables 1 and 2.

[0092] <Comparative Example 1> An adhesive (with a polyrotaxane content of 0% by mass) was prepared in the same manner as in Example 1, except that polyrotaxane-1 was not used. Laminates and pouches were then manufactured 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 by PR1, and polyrotaxane-2 by PR2. AD(PR1) means that polyrotaxane-1 is added to the urethane adhesive, and AD(PR2) means that polyrotaxane-2 is added to the urethane adhesive. PO indicates an olefin-based resin.

[0094] [Table 1]

[0095] [Table 2]

[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 was increased to 5.33 g. Pouches were then prepared in the same manner as in Example 1 or Example 3, and a bag drop test was conducted. As a result, the number of unbroken bags was not significantly different from Comparative Example 1, which did not contain polyrotaxane, and it was found that a polyrotaxane content of less than 17% by mass in the adhesive is optimal.

[0097] Invention 2 will be explained with the following experimental example. The materials used in the following experiment are as follows: <Sealant polyethylene film> A linear low-density polyethylene film with a thickness of 150 μm was used.

[0098] <Polyethylene base film> A biaxially oriented polyethylene film with a thickness of 25 μm was used.

[0099] <Adhesive> Urethane adhesive Manufactured by Toyo Morton Co., Ltd. Main component C: Polyester-based (60% by mass of solid components) Hardener D; Polyisocyanate-based (52.5% by mass of solid components) The ratio of main component C to hardener D was set to 18:4 (by mass).

[0100] <Polyrotaxane> Polyrotaxane-1 Manufactured by ASM (Advanced Soft Materials) Co., Ltd. SeRM Super Polymer SH1300P Axial molecular weight; 11000 Functional group modification; hydroxyl group

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

[0102] <Production of laminate (lamination)> By the dry lamination method, a sealant polyethylene film and a biaxially stretched polyethylene film were laminated to obtain a laminate. At this time, the adhesive was applied using a bar coater. The coating amount was adjusted with ethyl acetate so as to be about 3 - 3.5 g / m 2 After lamination, it was cured at 50°C for 4 - 5 days. After lamination, it was cured at 50°C for 4 - 5 days.

[0103] <Bag making> The laminate (laminate film) obtained above was made into a bag with a width of 130 mm × a height of 175 mm × a bottom material folding width of 36 mm and filled with 330 g of water. Sealing was carried out under the following conditions using a hot plate heat sealer. Sealing conditions: upper surface heating 200°C, 1.0 (s), 0.3 MPa Sealing width: about 5 mm

[0104] <Drop strength of the pouch> The pouch cooled overnight at 5°C was dropped vertically from a height of 150 cm for measurement.

[0105] <Example 5> A urethane-based adhesive (main agent C; 18 g, curing agent D; 4 g) and polyrotaxane-1 (0.26 g) were mixed to prepare an adhesive containing 2.0 mass% of polyrotaxane-1 with respect to the solid content of the combined main agent C and curing agent D and polyrotaxane-1. (As described above, the coating amount of this adhesive was adjusted with ethyl acetate so as to be about 3 - 3.5 g / m 2 .)

[0106] Next, the above adhesive was applied to a biaxially oriented polyethylene film (BAOPE), and a sealant polyethylene film (LLDPE) was laminated on top of it by dry lamination to obtain a laminate. After curing the laminate at 50°C for 4 days, pouches were made using this laminate (filled with 330g of water), and then dropped. bag The strength was evaluated.

[0107] <Comparative Example 2> An adhesive (with a polyrotaxane content of 0% by mass) was prepared in the same manner as in Example 5, except that polyrotaxane-1 was not used. Laminates and pouches were then manufactured 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] [Table 3] [Explanation of Symbols]

[0109] 1: Polyrotaxane 2: Axial molecule 3: Cyclic molecules 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 layered structure in which an adhesive layer is provided between two thermoplastic resin layers, The aforementioned adhesive layer is formed from an adhesive containing polyrotaxane. The laminate is characterized in that it contains 80% by mass or more of an olefin resin 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 comprising an ethylene resin and a propylene resin.

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

5. The laminate according to claim 1, wherein the adhesive layer contains a polyrotaxane in the urethane adhesive.

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

7. The laminate according to claim 1, wherein one of the two thermoplastic resin layers 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 the stretched film is provided with an inorganic coating or an organic coating.

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

12. A pouch obtained from the laminate described in claim 1.

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