laminate

Abstract

A laminate 10 is characterized by having a layer structure in which an adhesive layer 15 formed of an adhesive in which a polyrotaxane is incorporated is provided between two thermoplastic resin layers 11, 13, and contains 80 mass% or more of an olefin-based resin with respect to the total amount of the laminate 10.

Description

Technical Field

[0001] This invention relates to a laminate, and more specifically, to an olefin-based laminate comprising a large amount of an olefin resin, suitable for manufacturing pouches by heat sealing or ultrasonic sealing. Background Technology

[0002] Olefin resins, represented by propylene resins and ethylene resins, have been used in the packaging industry for a long time. In particular, due to their ease of heat sealing, small bags with unstretched olefin resin films as sealing resin layers are widely manufactured.

[0003] Furthermore, in packaging materials such as small bags, strength properties such as puncture resistance are required. Therefore, unstretched olefin resin films, as described above, are used in the form of laminates with reinforcing films such as stretched films. In such laminates, the reinforcing films are laminated onto the unstretched olefin resin film using dry lamination adhesives or the like.

[0004] Furthermore, in recent years, from an environmental perspective, there has been a growing demand for the recyclability of materials. Therefore, in laminates using unstretched olefin resins, there is a requirement to maximize the olefin resin content and to minimize the use of materials other than olefin resins. This is because laminates containing a large amount of olefin resins and exhibiting high single-material properties can be reused as olefin resins.

[0005] However, bags made using laminates containing large amounts of olefin resins have low impact resistance and drop strength, and often break when dropped from a certain height, requiring improvement.

[0006] Furthermore, in recent years, polymers with a molecular structure known as polyrotaxanes have been developed. These polymers are complexes of molecules with a chain-like axis molecule penetrating multiple cyclic molecules within the ring, and large groups bonded to both ends of the axis molecule; the cyclic molecules cannot detach from the axis molecule due to steric hindrance. Such complexes are called supramolecular structures. Various applications have been proposed for polyrotaxanes.

[0007] For example, Patent Document 1 proposes a laminate for vacuum insulation materials formed by bonding a thermally fused adhesive layer and a gas barrier layer using an adhesive containing polyrotaxane. In this laminate, because polyrotaxane is incorporated into the adhesive, the adhesive follows the expansion and contraction of each layer, resulting in no interlayer delamination and excellent gas barrier properties.

[0008] Furthermore, Patent Document 2 proposes a battery packaging material with an outer layer formed of polyrotaxane. In this battery packaging material, the outer layer is not composed of PET or Ny, but of polyrotaxane, thus improving abrasion resistance and scratch resistance.

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

[0010] Thus, various applications have been proposed for polyrotaxane, but its application in adhesives used in laminates containing large amounts of olefin resins with high single-material properties has not been studied at all. Existing technical documents Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2021-1650 Patent Document 2: Japanese Patent No. 6153183 Patent Document 3: Japanese Patent No. 6655555 Summary of the Invention The problem that the invention aims to solve

[0012] Therefore, the object of the present invention is to provide an olefin-based laminate containing a large amount of olefin resin, which is suitable for recycling and suitable for making small bags with excellent impact resistance and drop strength. Another object of the present invention is to provide an olefin-based laminate based on an olefin-based resin obtained by using an adhesive incorporating polyrotaxane. Technical solution

[0013] According to the present invention, a laminate is provided having a layer structure in which an adhesive layer is disposed between two thermoplastic resin layers, characterized in that the adhesive layer is formed of an adhesive formulated with polyrotaxane, and the laminate contains 80% by mass or more of an olefin resin relative to the total amount of the laminate.

[0014] In the laminates of the present invention (hereinafter referred to as olefin-based laminates), the following scheme is preferably applied. (1) The olefin resin is an ethylene resin or a propylene resin. (2) The olefin resin is a resin composition comprising ethylene resin and propylene resin. (3) In the adhesive layer, polyrotaxane is incorporated in an amount of less than 17% by mass. (4) In the adhesive layer, polyrotaxane is incorporated into the urethane adhesive. (5) In the polyrotaxane, the functional group at the end of the side chain of the cyclic molecule is a hydroxyl group. (6) Of the two thermoplastic resin layers, one thermoplastic resin layer is an unstretched sealing film formed from the olefin resin, and the other thermoplastic resin layer is formed from an unstretched film or a stretched film. (7) The other thermoplastic resin layer is formed by a stretch film, wherein an inorganic coating or an organic coating is provided on the stretch film. (8) An intermediate thermoplastic resin layer is provided between the thermoplastic resin layer of one party and the thermoplastic resin layer of the other party. (9) The other thermoplastic resin layer is a stretched film, the intermediate thermoplastic resin layer is an unstretched film or a stretched film, and at least one of the other thermoplastic resin layer or the intermediate thermoplastic resin layer is formed of the olefin resin. (10) An inorganic coating or an organic coating is provided on at least one of the stretch film forming the thermoplastic resin layer of the other party or the stretch film forming the intermediate thermoplastic resin layer.

[0015] According to the present invention, a small bag obtained from the above-described olefin-based laminate is also provided. Invention Effects

[0016] The olefin-based laminate of the present invention has a basic structure in which an adhesive layer is disposed between two thermoplastic resin layers, and contains 80% by mass or more of olefin-based resin relative to the total mass of the laminate. Therefore, the olefin-based resin exhibits high single-material properties and excellent recyclability.

[0017] Furthermore, in this invention, with the olefin resin content within the aforementioned range, a small amount of materials other than olefin resins are used, particularly adhesives formulated with polyrotaxane. As a result, the pouches (bag-shaped containers) formed from this laminate, although almost entirely composed of olefin resins, exhibit high drop strength and effectively prevent breakage caused by drops from heights.

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

[0019] Figure 1 This is a diagram illustrating the molecular structure of polyrotaxane used in this invention. Figure 2 This is a diagram illustrating the basic layer structure of the olefin-based laminate of the present invention. Figure 3 It means by Figure 2 A cross-sectional diagram of the small bag obtained from the laminated body. Detailed Implementation

[0020] <Polyrotaxane> First, in this invention, polyrotaxane incorporated in the adhesive layer will be described. Polyrotaxanes are well-known compounds, such as... Figure 1 As shown, the polyrotaxane molecule, represented as a whole by 1, has a composite molecular structure formed by chain-like axonal molecules 2 and cyclic molecules 3. That is, multiple cyclic molecules 3 enclose the chain-like axonal molecules 2, and the axonal molecules 2 penetrate the interior of the rings possessed by the cyclic molecules 3. Therefore, the cyclic molecules 3 can slide freely on the axonal molecules 2, but large terminal groups 4 are formed at both ends of the axonal molecules 2 to prevent the cyclic molecules 3 from falling off the axonal molecules 2.

[0021] That is, the cyclic molecule 3 can slide on the axial molecule 2. Therefore, the adhesive layer with polyrotaxane has a high degree of molecular freedom and can easily follow the expansion and contraction of the adjacent layer and the stress dispersion when a load is applied. This is the main reason for improving impact resistance.

[0022] In such polyrotaxanes, the chain-like axial molecule 2 is known to be of various types, for example, as long as it can pass through the ring of the cyclic molecule, it can be straight or branched, and is usually formed by polymers.

[0023] Polymers that form such axial molecules 2 include: polyvinyl alcohol, polyvinylpyrrolidone, cellulose 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 resins (polyethylene, polypropylene, etc.), polyester, polyvinyl chloride, styrene resins (polystyrene, acrylonitrile-styrene copolymer resins, etc.), acrylic resins (poly(meth)acrylic acid, ... Polymethyl methacrylate (PMMA), polymethyl acrylate (PMMA), acrylonitrile-methyl acrylate copolymer resin, etc., polycarbonate, urethane, 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, polyimide, polyacetic anhydride, polyurea, polysulfide, polyphosphazene, polyketone, polyphenylene, polyhalogenated olefins, etc. These polymers can be copolymerized appropriately or modified polymers.

[0024] In this invention, the polymer forming the axial molecule 2 is preferably polyethylene glycol, polyisoprene, polyisobutylene, polybutadiene, polypropylene glycol, polytetrahydrofuran, polydimethylsiloxane, polyethylene, polypropylene, polyvinyl alcohol, or polyvinyl methyl ether. Polyethylene glycol is most preferred from the perspective of affinity and reactivity with adhesives that combine with polyrotaxane. Furthermore, from the perspective of material properties, polyethylene and polypropylene are preferred.

[0025] Furthermore, examples of large terminal groups 4 formed at both ends of axis 2 include adamantyl, triphenylmethyl, fluorescein, dinitrophenyl, and pyrene matrix. In particular, adamantyl is preferred from the perspective of ease of introduction.

[0026] There is no particular limitation on the molecular weight of the axial molecule, but if it is too large, there is a tendency for its affinity with the adhesive components to decrease; if it is too small, there is a tendency for the mobility of the cyclic molecule to decrease and the effect of improving impact resistance to be reduced. From this point of view, the weight-average molecular weight Mw of the axial molecule 2 is preferably in the range of about 1,000 to 100,000.

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

[0028] Multiple ring molecules 3, as described above, are attached to one axial molecule 2. However, when the maximum number of ring molecules that can be attached to each axial molecule is set to 1, the number of ring molecules 3 attached is typically 0.001 to 0.6, more preferably 0.002 to 0.5, and even more preferably in the range of 0.003 to 0.4. If the number of ring molecules 3 attached is too large, the ring molecules 3 exist densely relative to one axial molecule, thus reducing their mobility and tending to reduce the effect of improving impact resistance. Furthermore, if the number of attached molecules is too small, the gap between the axial molecules 2 becomes narrower, still tending to reduce mobility and the effect of improving impact resistance.

[0029] It should be noted that the maximum number of ring molecules 3 encapsulated relative to an axial molecule 2 can be calculated from the length of the axial molecule 2 and the thickness of the rings possessed by the ring molecules 3. For example, taking the case where the axial molecule 2 is formed from polyethylene glycol and the cyclic molecule 3 has an α-cyclodextrin ring, the maximum number of inclusions is calculated as follows. That is, the amount of two repeating units [-CH2-CH2O-] in polyethylene glycol 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 taken as the maximum number of inclusions in the cyclic molecule. This maximum number of inclusions is set to 1.0, and the number of inclusions in the cyclic molecule is adjusted to the range described above.

[0030] Furthermore, in this invention, the rings of the aforementioned cyclic molecule 3 can also be incorporated into side chains. These side chains... Figure 1 The number 5 represents the middle. That is, by introducing such a side chain 5 into the ring, a suitable space can be more reliably formed between adjacent axial molecules 2, which is beneficial to improving impact resistance. In addition, by introducing the side chain 5, the adhesive component that is coordinated with polyrotaxane can be made reactive, forming a cross-linked structure with the adhesive, thereby further improving the strength when the bag is formed.

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

[0032] The aforementioned side chain 5 is introduced by modifying the functional groups of the ring in the cyclic molecule 3. For example, an α-cyclodextrin ring has 18 hydroxyl groups as functional groups, and the side chain is introduced through these hydroxyl groups. That is, a maximum of 18 side chains can be introduced for one α-cyclodextrin ring. For example, if a side chain is bonded to 9 of the 18 hydroxyl groups of the 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.

[0033] In this invention, the side chain 5 (organic chain) described above can be linear or branched, as long as it does not impair the polyrotaxane property of the cyclic molecule 3 sliding on the axial molecule 2. The side chain of appropriate size can be introduced by reacting an appropriate compound with the functional groups of the ring using ring-opening polymerization, free radical polymerization, cationic polymerization, anionic polymerization, RAFT polymerization, NMP polymerization, etc.

[0034] For example, side chains from cyclic compounds such as cyclic lactones, cyclic ethers, cyclic acetals, cyclic amines, cyclic carbonates, cyclic imino ethers, and cyclic thiocarbonates can be introduced through ring-opening polymerization. Among these, cyclic ethers, cyclic siloxanes, lactones, and cyclic carbonates are preferred from the viewpoints of easy availability, high reactivity, and ease of size (molecular weight) adjustment.

[0035] It should be noted that the compound used to introduce side chain 5 via free radical polymerization is a free radical polymerizable compound, but the ring of the cyclic molecule 3 of polyrotaxane 1 does not have an active site that can become a free radical initiation site. Therefore, before reacting the free radical polymerizable compound, the functional group (hydroxyl group) of the ring needs to be reacted with a compound used to form a free radical initiation site, such as an organohalogen compound, to form an active site that can become a free radical initiation site.

[0036] Furthermore, as a free radical polymerizable compound for introducing side chains through free radical polymerization, it is preferable to use a compound having at least one functional group having an ethylene unsaturated bond, such as (meth)acryloyl, vinyl, styrene, etc. (hereinafter referred to as an ethylene unsaturated monomer).

[0037] As can be understood from the above description, the side chain 5 introduced into the ring of cyclic molecule 3 may sometimes be a repeating unit such as -O-bond, -NH-bond or -S-bond, or have substituents such as hydroxyl, carboxyl, acyl, phenyl, halogen atom, silyl, mercapto, vinyl, NCO group, NCS group, etc., depending on the way it is introduced. Furthermore, depending on the type of functional groups possessed by the compound used to introduce side chain 5, a portion of the side chain may sometimes bond with the functional groups of the rings of cyclic molecules possessed by other axial molecules, forming a pseudo-crosslinked structure.

[0038] In this invention, the most preferred polyrotaxane 1 is a polyethylene glycol with adamantyl group as the terminal group 4 bonded to it as the axial molecule 2, and a cyclic molecule 3 having an α-cyclodextrin ring, and then introducing a polyrotaxane with side chains 5 such as polycaprolactone (terminally OH group).

[0039] <Basic Structure> Reference Figure 2 The olefin-based laminate 10 of the present invention, which uses the above-mentioned polyrotaxane, 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 an olefin resin, particularly 90% by mass or more of an ethylene resin or a polypropylene resin.

[0040] That is, the laminate 10 of the present invention contains a large amount of olefin resin, thus exhibiting high single-material properties and excellent recyclability. For example, when it is recycled as waste after use, it can be reused as an olefin resin, either alone or mixed with unused olefin resin, after appropriate crushing, washing, drying, etc., thus suppressing the degradation of physical properties caused by recycling.

[0041] Thermoplastic resin layers 11 and 13; exist Figure 2 In the formation of thermoplastic resin layers 11 and 13, olefin resins are typically used to achieve the required olefin resin content. Examples of such olefin resins include ethylene resins such as low-density polyethylene, high-density polyethylene, and copolymers of ethylene with other olefins; and propylene resins such as copolymers of polypropylene, propylene with other olefins. While other olefin resins may also be used, ethylene resins and propylene resins, which are widely used in the packaging materials industry, are preferred.

[0042] Furthermore, the olefin resin can be a resin composition comprising ethylene resin and propylene resin. Additionally, the thermoplastic resin layer 11 can be formed from ethylene resin and propylene resin, and the thermoplastic resin layer 13 can be formed from propylene resin and ethylene resin. However, to improve the properties of a single material and achieve the most suitable form for recyclability, it is preferable to use the same olefin resin to form the thermoplastic resin layers 11 and 13.

[0043] Furthermore, in this invention, the aforementioned laminate 10 uses one of the thermoplastic resin layers 11 as a sealing resin layer, such as... Figure 3 As shown, the pouch 20 is suitable for manufacturing by bonding the sealing resin layers together using heat sealing or ultrasonic sealing. In this case, the thermoplastic resin (olefin resin) layer 11 used as the sealing resin layer is formed from an unstretched olefin resin. Furthermore, the other thermoplastic resin (olefin resin) layer 13, which is laminated by the adhesive layer 15, is preferably stretched to improve its strength and heat resistance. It should be noted that, especially for heat treatments such as distillation sterilization, it also exhibits excellent heat resistance and produces bags with high strength. From this perspective, propylene resin is the preferred choice as an olefin resin.

[0044] It should be noted that in the olefin-based laminate 10 used in the molding of the small bag 20, the unstretched olefin-based resin layer 11 (cast film) typically has a thickness of 30 to 150 μm. In addition, the stretched olefin-based resin layer 13 (stretched film) is stretched and heat-fixed to improve 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 by the previously described adhesive containing polyrotaxane. That is, by means of such an adhesive, one olefin-based resin layer 11 (unstretched film) and the other olefin-based resin layer 13 (stretched film) are bonded together, thereby obtaining a small bag 20 with excellent heat resistance, impact resistance, etc. It should be noted that the adhesive layer 15 only needs to exist between the thermoplastic resin layers 11 and 13, and does not necessarily have to be adjacent to these resin layers 11 and 13.

[0046] There are no particular limitations on the adhesives used in conjunction with polyrotaxane; dry lamination adhesives such as urethane adhesives and epoxy adhesives can be used. However, to maximize the utilization of the properties of polyrotaxane, urethane adhesives are preferred.

[0047] In particular, urethane-based adhesives are effective when epoxy, cyclosulfide, thiocyclobutyl, OH, SH, NH2, NCO, or NCS groups are introduced as functional groups into the side chain 5 of the polyrotaxane. For example, urethanes are formed through the reaction of polyols and polyisocyanates. That is, when the aforementioned functional groups are introduced into the side chain 5 of the polyrotaxane, a cross-linked structure is formed by introducing the side chain 5 of the polyrotaxane into the polymer chain of the urethane formed by the reaction of polyols and polyisocyanates, which is most preferably beneficial for improving the strength of the bag.

[0048] The polyols used in the formation of urethane adhesives are compounds having two or more OH groups per molecule. Representative examples include di-, tri-, tetra-, penta-, and hexa-hydroxy compounds; polyesters (polyester polyols) containing two or more OH groups per molecule; polyethers (hereinafter referred to as polyether polyols) containing two or more OH groups per molecule; polycarbonates (polycarbonate polyols) containing two or more OH groups per molecule; polycaprolactones (polycaprolactone polyols) containing two or more OH groups per molecule; and acrylic polymers (polyacrylic acid polyols) containing two or more OH groups per molecule. Considering high affinity for polyrotaxane, polyester polyols are the most preferred polyols in this invention.

[0049] The polyester polyols described above are polymers obtained through the condensation reaction of polyacids such as adipic acid and phthalic acid with polyols. Examples of polyols that react with polyacids 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, 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, and 2-isocyanate methyl-3-(3-isocyanate propyl)-5-isocyanate methyl-bicyclo[2,2,1]-heptane; aromatic isocyanates such as phenylenediethylene diisocyanate, bis(isocyanate ethyl)benzene, bis(isocyanate methyl)naphthalene, and bis(isocyanate methyl)diphenyl ether; and sulfur-containing aliphatic isocyanates such as thiodiethyl diisocyanate. Aliphatic sulfide isocyanates such as bis[2-(isocyanate-methylthio)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; sulfonate isocyanates such as 4-methyl-3-isocyanate-benzenesulfonyl-4'-isocyanate-phenol ester; aromatic sulfonamide isocyanates such as 4-methyl-3-isocyanate-benzenesulfonylaniline-3'-methyl-4'-isocyanate; sulfur-containing heterocyclic isocyanates such as thiophene-2,5-diisocyanate, etc.

[0051] In the polyisocyanate, the isocyanate group (NCO group) is typically used in an amount of about 0.8 to 1.2 moles relative to 1 mole of hydroxyl groups in the polyol.

[0052] In this invention, polyrotaxane is present in the adhesive layer 15 formed from the adhesive (e.g., a urethane-based adhesive obtained from polyester polyol and polyisocyanate) in an amount of less than 17% by mass, particularly less than 10% by mass. When polyrotaxane is present in such an amount, the stress-dispersing effect resulting from the sliding of the cyclic molecules 3 of polyrotaxane can be fully utilized, for example, improving impact resistance, and effectively suppressing bag breakage caused by dropping during the fabrication of the pouch 20.

[0053] In a dynamic viscoelasticity test (10 Hz) at 5°C, adhesive coatings containing polyrotaxane in the amounts described above exhibited increased loss tangent (tanδ) and improved vibration absorption, as confirmed in the examples described later. For example, in Examples 1 to 4 described later, polyrotaxane was incorporated into the urethane adhesive. The loss tangent (tanδ) of such polyrotaxane-incorporated adhesive coatings in a dynamic viscoelasticity test (10 Hz) at 5 °C was 0.21 or higher, and particularly preferably 0.23 or higher, indicating improved vibration absorption.

[0054] Furthermore, in order to achieve the effect of firmly adhering the films together, the adhesive coating containing polyrotaxane in the aforementioned amount and with improved vibration absorption should preferably have the same elastic modulus as the adhesive coating without polyrotaxane. However, as shown in the results of the examples described later, the adhesive coatings of Examples 1 to 4, like Comparative Example 1 which used an adhesive coating without polyrotaxane, had a storage modulus E' exceeding 1 GPa in the dynamic viscoelasticity test (10 Hz) at 5°C.

[0055] In this invention, the adhesive containing polyrotaxane as described above is supplied for use by adding polyrotaxane to the reactive components that form the adhesive (e.g., a coating composition in which polyester polyol and polyisocyanate are dispersed in an organic solvent). Specifically, the coating composition containing polyrotaxane is coated onto a film forming one olefinic resin layer, then the film forming the other olefinic resin layer is pressed together, heated to a suitable temperature, and subjected to polymerization curing and solvent removal, thereby forming an adhesive layer 15. The thermoplastic resin layer 11 and thermoplastic resin layer 13 are bonded together by the adhesive layer 15. Figure 2 The olefin-based laminate 10 shown.

[0056] In such a laminate 10, the adhesive layer 15 is very thin, which is within the range that satisfies the content of the olefin resin in the laminate 10. For example, it is typically 2 to 5 g / m³. 2 The thickness on the left and right sides.

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

[0058] Bag making can be carried out using known methods. For example, an empty pouch can be made by using a three-sided seal of two olefin-based laminates 10, 10, filling the contents through the opening, and finally closing the opening by heat sealing. Alternatively, an empty pouch can be made by folding a sheet of olefin-based laminate 10 in half and heat-sealing both ends. In this case, it is not necessary to heat-seal the bottom. Moreover, an olefin-based laminate 10 specifically for the sides or bottom can be used to make the empty pouch. This method is advantageous in increasing the volume of the pouch 20 or in imparting uprightness.

[0059] Thus, the bag filled with contents, made from the olefin-based laminate 10 of the present invention, exhibits excellent single-material properties for olefin-based resins such as polypropylene and polyethylene. Because it contains a large amount of these olefin-based resins, it also has excellent recyclability as an olefin-based resin. Furthermore, although it contains a large amount of olefin-based resin, it also has high impact resistance and high drop strength, effectively suppressing bag breakage caused by drops from heights.

[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, it can be used in various ways to improve the properties required by packaging materials such as packaging bags.

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

[0062] Furthermore, by providing an inorganic coating on at least one surface of the olefin resin layer 13 (the stretched olefin resin layer) or a stretched olefin resin layer laminated thereon via the adhesive layer 15, it is possible to improve the barrier properties against oxygen and the like. Such inorganic coatings include vapor-deposited films of various metals or metal oxides, coatings primarily composed of silicon oxides, coatings of metal alkoxide condensates, coatings formed through the crosslinking reaction of carboxylic acids and metals, and coatings formed by the dispersion of metal oxides. Moreover, the aforementioned coating is preferably provided as a protective film (so-called top coating) on ​​the vapor-deposited film.

[0063] This vapor-deposited film is an inorganic film formed through physical vapor deposition methods such as sputtering, vacuum evaporation, and ion plating, or chemical vapor deposition methods such as plasma CVD (chemical vapor deposition). For example, it may be a film formed from various metals or metal oxides. Because such vapor-deposited films are formed from inorganic materials, they exhibit higher oxygen barrier properties compared to gas-barrier resins such as ethylene-vinyl alcohol copolymers.

[0064] Furthermore, the above-mentioned vapor-deposited film can be formed directly on the surface of the thermoplastic resin film. 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 urethane, and form the vapor-deposited film on the coating (so-called tackifying coating).

[0065] In this invention, from the viewpoint of forming a dense film and ensuring particularly high oxygen barrier properties, it is preferable to form an inorganic coating by vapor deposition of a film formed of silicon oxide, aluminum oxide, silicon dioxide-alumina composite oxide, etc. In particular, from the viewpoint of ensuring transparency (haze of less than 5%) and displaying good visual visibility, it is most preferable to form an inorganic coating by vapor deposition of a silicon oxide film.

[0066] Furthermore, on the aforementioned vapor-deposited film, it is preferable to provide the inorganic coating as a protective film layer (top coating). This coating penetrates into the fine defects (cracks) generated within the vapor-deposited film, functioning as a protective film to prevent the growth of existing defects and the formation of new ones. From the viewpoint of adhesion to the vapor-deposited film, a coating containing metal alkoxides such as alkoxysilanes or alkoxytitanium, and partially condensed, is preferred.

[0067] The thickness of the aforementioned inorganic coating 1b varies depending on the required level of oxygen barrier properties. However, in the case of vapor-deposited films, the thickness is designed to ensure that the properties of the thermoplastic resin film 1a, which serves as the substrate during vapor deposition, are not impaired, and that 1cc / m is maintained. 2 A thickness with an oxygen permeability of less than / day / atom is preferable, typically around 1000nm to 10nm, especially 100nm to 10nm.

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

[0069] Furthermore, to ensure gas barrier properties, an organic coating can be used instead of the aforementioned inorganic coating, such as a coating based on polyvinyl alcohol or ethylene-vinyl alcohol copolymer. While the coating can be formed directly on the surface of the thermoplastic resin film, to improve the smoothness 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 urethane, thus forming an organic coating on the coating (the so-called tackifying coating layer).

[0070] Furthermore, as long as the olefin resin content is within the aforementioned large range, layers containing resins other than olefin resins can also be provided. For example, to suppress the decrease in impact resistance caused by the relaxation of orientation of the tensile layer due to puncture strength and heat treatment, a layer of a tensile film containing a resin with a higher melting point than olefin resins such as polyamide and ethylene-vinyl alcohol copolymer can be provided as a strength reinforcing layer. Polyamide is the most preferred high-melting-point resin as such a strength reinforcing layer.

[0071] It should be noted that there are no particular limitations on the polyamides mentioned above, and various polyamides can be exemplified, but nylon 6, nylon 6,6, nylon 11, nylon 12, nylon 13, nylon 6 / nylon 6,6 copolymers, aromatic nylons (e.g., poly(m-phenylene adipamide)), amorphous nylons (e.g., nylon 6I / nylon 6T), etc., are generally preferred.

[0072] Furthermore, in order to satisfy the single material properties (large amount of olefin resin content) of the olefin laminate 10 in the stretch film forming the above-mentioned strength enhancement layer, olefin resin (e.g., acrylic resin) can be mixed in the high melting point resin within a range without impairing the high strength. Alternatively, a multilayer stretch film of olefin resin stretch film and high melting point resin stretch film can be provided as the strength enhancement layer.

[0073] For example, in this invention, the unstretched layer of the propylene resin, which is most preferably used as an olefin resin, is represented by CPP, the stretched layer by OPP, the adhesive layer containing polyrotaxane by AD, the inorganic coating by INOR, and the strength reinforcing layer by PP / Ny. The preferred olefin laminate 10 has the following layer structure. CPP / AD / (INOR)OPP CPP / AD / (INOR)OPP / AD / OPP CPP / AD / OPP / AD / (INOR)OPP CPP / AD / (PP / Ny) / AD / (INOR)OPP It should be noted that (INOR) means that an inorganic coating may or may not be present, and the inorganic coating may be formed on either side of the OPP. In addition, PP represents acrylic resin and Ny represents nylon.

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

[0075] The present invention-1 is illustrated by the following experimental examples. The materials used in the following experiments are described below.

[0076] <One side of the thermoplastic resin layer (unstretched sealing film)> CPP membrane: TORAYFAN ZK500 manufactured by TORAY ADVANCED FILM Co., Ltd. Thickness: 70μm. The resin composition of the membrane; Polypropylene (PP) content is 80% by mass. Polyethylene (PE) component 20% by mass.

[0077] <Thermoplastic resin layer of the other party> An inorganic-coated gas-barrier stretched polypropylene film is formed on one side of the surface: BAOPP membrane. Thickness: 20μm. Composition: OPP / coating (tackifying coating) / inorganic coating. Inorganic coatings: vapor-deposited films mainly composed of silicon oxide and protective films (top coatings) mainly composed of silicon or silicon oxide.

[0078] <Adhesive> Carbamate adhesives Made by Toyo Morton Co., Ltd. Main agent A: Polyester-based (50% by mass of solids). Curing agent B; polyisocyanate system (70% by mass of solids). Main agent A : Curing agent B = 44 : 4 (mass ratio).

[0079] <Polyrotaxane> Polyrotaxane-1 Made by ASM (Advanced Soft Materials) Co., Ltd. SeRM Super Polymer SH1300P. Axial molecular weight: 11000. 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 groups

[0080] The fabrication of the laminate (laminated film), bag making, and the determination of various physical properties are carried out as follows.

[0081] <Lamination (Creation of Laminated Materials)> An unstretched sealing film (CPP film) and a gas-barrier stretched film (BAOPP film) are laminated using a dry lamination method to obtain a laminate. At this point, an adhesive is applied using a doctor blade coater. It should be noted that the coating amount is adjusted with ethyl acetate to approximately 3–3.5 g / m³ based on solids. 2 Furthermore, the CPP membrane is laminated using an inorganic coating method facing the BAOPP membrane. After lamination, allow it to cure at 50°C for 4-5 days.

[0082] Bag Making The laminated film obtained above was cut into two pieces measuring 140mm × 180mm, and 200g of water was added to make bags, resulting in small bags. Bag making was carried out using an Impulse sealing machine manufactured by Fuji Impulse Co., Ltd., under the following conditions. Sealing conditions: 185℃, 1.4(s). Sealing width: approximately 5mm.

[0083] <Small bag drop strength> The test was conducted by dropping two bags, stacked horizontally on top of each other, from a height of 120 cm after cooling at 5°C overnight. The lower bag was used as the test bag. N (number of tests) ≥ 3, and the average number of times the bag did not break was measured.

[0084] <Dynamic viscoelasticity of adhesive coatings> A dynamic viscoelasticity measuring apparatus manufactured by Seiko Instruments Co., Ltd. was used. The test conditions are as follows. Test film: 20mm in length and 10mm in width. Clamp spacing: 5mm. Temperature range: -20℃~40℃. Heating rate: 2℃ / min. Frequency: 10Hz. tanδ (loss tangent): It is calculated from the loss modulus (E”) / energy storage modulus (E’) at 5℃. E' (Storage Modulus): Calculated from the value at 5℃.

[0085] <Amount of olefinic resin relative to the total amount of the laminate> The amount (mass %) of olefin-based resin can be determined using the following formula. [Formula 1]

[0086] In the above formula, the adhesive application rate is 3.25 g / m². 2 The thickness is set to 3.5 μm, and the density is assumed to be 0.93 g / cm³. 3 Perform the calculation. The density of polypropylene (PP) is assumed to be 0.90 g / cm³. 3 Calculations were performed. Furthermore, the density of polyethylene (PE) was assumed to be 0.93 g / cm³. 3 Perform the calculation.

[0087] <Example 1> A urethane-based adhesive (44 g of main agent A and 4 g of curing agent B) and polyrotaxane-1 (0.48 g) were prepared, with polyrotaxane-1 comprising 1% (9% by mass) of the total solids of the combined main agent A, curing agent B, and polyrotaxane-1. The dynamic viscoelasticity of the adhesive coating was evaluated and is shown in Table 1. (As previously explained, the coating weight of this adhesive was adjusted with ethyl acetate to approximately 3–3.5 g / m² based on solids.) 2 ).

[0088] Next, the above-mentioned adhesive is coated on the CPP film, and a BAOPP film is laminated on it by dry lamination to obtain a laminate. After curing the laminate at 50°C for 4 days, the laminate was used to make small bags (filled with 200g of water), and the bag drop strength was evaluated. In addition, the olefin resin content relative to the total amount of the laminate was calculated. The results are shown in Table 2.

[0089] <Example 2> The amount of polyrotaxane-1 was increased by 1.48 g, and the adhesive (polyrotaxane-1 content was 5.6% by mass) was prepared in the same manner as in Example 1. The dynamic viscoelasticity of the adhesive coating was evaluated. Furthermore, in addition to using this adhesive, the laminate and pouches were manufactured in the same manner as in Example 1, 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. The laminate and bag were then fabricated, and various properties were evaluated. The results are shown in Tables 1 and 2.

[0091] <Example 4> Instead of polyrotaxane-1, polyrotaxane-2 was used. Otherwise, the adhesive was prepared in the same manner as in Example 2. The laminate and bag were then manufactured, and various properties were evaluated. The results are shown in Tables 1 and 2.

[0092] <Comparative Example 1> Without using polyrotaxane-1, the adhesive (polyrotaxane content 0% by mass) was prepared in the same manner as in Example 1. Except for the use of this adhesive, the laminate and bag were manufactured in the same manner as in Example 1, and various properties were evaluated. The results are shown in Table 2.

[0093] In Tables 1 and 2, adhesives are represented by AD, polyrotaxane-1 by PR1, and polyrotaxane-2 by PR2. Furthermore, AD(PR1) indicates that polyrotaxane-1 is incorporated into a urethane-based adhesive, and AD(PR2) indicates that polyrotaxane-2 is incorporated into a urethane-based adhesive. PO indicates olefin-based resin.

[0094] [Table 1]

[0095] [Table 2]

[0096] <Reference Example> The amount of polyrotaxane-1 or polyrotaxane-2 was increased to 5.33 g. Otherwise, the process was the same as in Example 1 or Example 3, to prepare an adhesive with a polyrotaxane-1 or polyrotaxane-2 content of 17.7% by mass. Small bags were made in the same manner as in Example 1 or Example 3, and bag-drop tests were conducted. The results showed that the number of bags that did not break was not significantly different from that in Comparative Example 1 without polyrotaxane. A polyrotaxane content of less than 17% by mass in the adhesive was optimal.

[0097] The present invention-2 will be described through the following embodiments. The materials used in the following experiments are described below. <Sealed polyethylene film> A straight-chain low-density polyethylene film with a thickness of 150μm was used.

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

[0099] <Adhesive> Carbamate adhesives Made by Toyo Morton Co., Ltd. Main agent C; polyester (60% by mass of solids). Curing agent D; polyisocyanate (solid content 52.5% by mass). Main agent C : Curing agent D = 18 : 4 (mass ratio).

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

[0101] The fabrication of the laminate (laminated film), bag making, and the determination of various physical properties are carried out as follows.

[0102] <Lamination (Creation of Laminated Materials)> A sealant polyethylene film and a biaxially stretched polyethylene film were laminated using a dry lamination method to obtain a laminate. At this point, an adhesive was applied using a doctor blade coater. It should be noted that the coating amount was adjusted with ethyl acetate to approximately 3–3.5 g / m³ (solids content). 2 . After lamination, allow it to cure at 50°C for 4-5 days.

[0103] Bag Making The laminate obtained above is made into a film with a width of 130mm × a height of 175mm × a substrate fold width of 36mm, and filled with 330g of water. Sealing is performed using a hot plate heat sealer under the following conditions. Sealing conditions: upper surface heated to 200℃, 1.0(s), 0.3MPa. Sealing width: approximately 5mm.

[0104] <Small bag drop strength> The test was conducted by dropping two bags, which had been cooled at 5°C overnight, from a height of 120 cm with the bags horizontally stacked.

[0105] <Example 5> A urethane-based adhesive (main agent C: 18g, curing agent D: 4g) and polyrotaxane-1 (0.26g), wherein the solid content of the combined main agent C, curing agent D, and polyrotaxane-1 is 2%, are prepared to produce an adhesive containing 0% by mass. (As previously explained, the coating amount of this adhesive is adjusted with ethyl acetate to approximately 3–3.5 g / m² based on the solid content.) 2 ).

[0106] Next, the adhesive is applied to a biaxially stretched polyethylene film (BAOPE), and a polyethylene film (LLDPE) is laminated and sealed on it using a dry lamination method to obtain a laminate. After curing the laminate at 50°C for 4 days, the laminate was used to make small bags (filled with 330g of water), and the bag drop strength was evaluated.

[0107] <Comparative Example 2> Without using polyrotaxane-1, the adhesive (polyrotaxane content 0% by mass) was prepared in the same manner as in Example 5. Except for using this adhesive, the laminate and bag were manufactured in the same manner as in Example 1, and various properties were evaluated. The results are shown in Table 3.

[0108] [Table 3] Explanation of reference numerals in the attached figures

[0109] 1: Polyrotaxane 2: Axial molecules 3: Cyclic molecules 4: Terminal groups 5: Side chain 10: Olefin-based laminates 11: Thermoplastic resin layer 13: Thermoplastic resin layer 15: Adhesive layer 20: Small bag

Claims

1. A small bag, characterized in that, It is obtained from a laminate, the laminate having a layer structure in which an adhesive layer is disposed between two thermoplastic resin layers, wherein, The adhesive layer is formed of an adhesive formulated with polyrotaxane. The laminate contains at least 80% by mass of an olefinic resin relative to the total amount of the laminate. The adhesive layer contains polyrotaxane in an amount of 5.6% by mass or less.

2. The pouch according to claim 1, wherein, The olefin-based resin is an ethylene-based resin or a propylene-based resin.

3. The pouch according to claim 1, wherein, The olefin resin is a resin composition comprising ethylene resin and propylene resin.

4. The pouch according to claim 1, wherein, In the adhesive layer, polyrotaxane is incorporated into the urethane-based adhesive.

5. The pouch according to claim 1, wherein, In the polyrotaxane, the functional group at the end of the cyclic molecular side chain is a hydroxyl group.

6. The pouch according to claim 1, wherein, Of the two thermoplastic resin layers, one thermoplastic resin layer is an unstretched sealing film formed from the olefin-based resin, and the other thermoplastic resin layer is formed from an unstretched film or a stretched film.

7. The pouch according to claim 6, wherein, The other thermoplastic resin layer is formed from a stretch film, wherein the stretch film is provided with an inorganic coating or an organic coating.

8. The pouch according to claim 6, wherein, An intermediate thermoplastic resin layer is provided between one thermoplastic resin layer and the other thermoplastic resin layer.

9. The pouch according to claim 8, wherein, The other thermoplastic resin layer is a stretched film, the intermediate thermoplastic resin layer is an unstretched film or a stretched film, and at least one of the other thermoplastic resin layer or the intermediate thermoplastic resin layer is formed from the olefin-based resin.

10. The pouch according to claim 9, wherein, At least one of the stretch film forming the thermoplastic resin layer of the other party or the stretch film forming the intermediate thermoplastic resin layer is provided with an inorganic coating or an organic coating.

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