JP2013071438A - Laminate and packing material using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate and a packing material using the same, provided that: firstly, a laminate strength is excellent; secondly, the laminate strength does not degrade between a substrate and a sealant layer and has a high gas barrier property when a volatile material or various highly penetrating contents are enclosed in a packing bag formed of the laminate, wherein the substrate has a thin film layer consisting a metal foil or a deposition film of inorganic oxide laid on a substrate material; and thirdly, an adhesive layer exhibiting the properties can further be stably processed.SOLUTION: The lamination has at least an adhesive layer 3 and a sealant layer 4 in this order laid on a substrate material 1, wherein the adhesive layer 3 consists of a metal alkoxide and an isocyanate compound. A thin film layer 2 consisting of the metal foil or the deposition film of inorganic oxide is laid on the substrate material 1 and the adhesive layer 3 laid on the thin film layer 2. The thickness of adhesive layer 3 is 1 μm or less. The sealant layer consists of either a polyethylene resin or a polypropylene resin.

Description

  The present invention relates to a laminate in which an adhesive layer and a sealant layer are provided in this order on a base material provided with a thin film layer made of a metal foil or an inorganic oxide vapor deposition film, and a packaging material using the same.

  Conventionally, articles that need to be sealed off from the outside air such as food and pharmaceuticals have been stored in metal cans and glass bottles. In recent years, packaging materials have been made using lightweight laminates due to environmental considerations and increased cost awareness. Such a laminate is desired by laminating a variety of different materials, such as (1) gas barrier properties that allow shut-off from the outside air, and (2) processing characteristics that allow various processing such as laminating. Product characteristics can be obtained. For example, a laminate in which a base material layer such as polyester, nylon, polypropylene, etc./an adhesive layer made of an isocyanate compound / sealant layer is laminated in this order has been proposed (see Patent Document 1).

  In the laminate as described above, a plastic film provided with a thin film layer made of a metal foil or an inorganic oxide vapor-deposited film is used in order to improve gas barrier properties against the outside air. However, since metals and inorganic oxides have poor wettability to organic solvents, it is difficult to firmly adhere to the millisealant layer through an adhesive layer made of an organic material such as an isocyanate compound. In particular, when the laminate is processed into a packaging bag (pouch) and the strong permeable substance is retained inside, the strong permeable substance penetrates from the sealant layer on the inner wall side and weakens the adhesion between the base material layer and the sealant layer. Therefore, it is difficult to fix the sealant layer firmly enough to withstand practical use. For this reason, the method of adhering suitably the layer which consists of a composition containing a metal, an inorganic substance, and resin (organic substance) has been sought.

  In addition, the addition of a metal alkoxide to the isocyanate compound has improved the laminate strength on the surface of the metal / inorganic oxide. It was confirmed that this could occur.

JP 2005-335374 A

  The present invention has excellent laminating strength first, and secondly, a laminated body is formed into a packaging bag, and even if a volatile substance or various strongly permeable contents are enclosed in this, the metal foil or inorganic oxide Laminate strength between the base material and the sealant layer provided with a thin film layer made of a vapor-deposited film does not decrease, and has a high gas barrier property. Third, the adhesive layer that expresses the above performance can be processed stably. It is an object of the present invention to provide a laminate and a packaging material using the same.

  The present invention made to solve the above-mentioned problems is a laminate comprising at least an adhesive layer and a sealant layer in this order on a substrate, and the adhesive layer is composed of a metal alkoxide and an isocyanate compound. .

  A thin film layer made of a metal foil or an inorganic oxide vapor deposition film is provided on the base material, and the adhesive layer is provided on the thin film layer. For example, the sealant layer is made of either a polyethylene resin or a polypropylene resin. The metal alkoxide includes any of silicon, aluminum, titanium, and zirconium. Furthermore, the metal alkoxide is an alcohol having an alkoxyl group of 2 or more carbon atoms, preferably the metal alkoxide is a silane coupling agent, and the silane coupling agent is preferably a silane coupling agent having an amino group. It is.

  The isocyanate compound is, for example, a bifunctional isocyanate monomer or a bifunctional isocyanate monomer adduct, biuret compound, isocyanurate or adduct, burette, or a derivative of a trifunctional monomer of the isocyanurate type.

  Furthermore, the present invention is characterized in that the laminate is used as a packaging material.

  The laminate of the present invention comprises an adhesive layer and a sealant layer in this order on a base material provided with a thin film layer comprising a metal foil or an inorganic oxide vapor deposition film, and the adhesive layer comprises a mixture of a metal alkoxide and an isocyanate compound. The adhesive layer can be formed as a very thin and dense layer, and the thin film layer and the sealant layer can be firmly bonded. Furthermore, by using this laminate as a packaging material, even if an article containing a strong permeable substance is packaged in its contents, the adhesive layer is not affected by the strong permeable substance. Will not cause. Further, by using an alcohol having 2 or more carbon atoms as the alkoxyl group of the metal alkoxide, the stability of the mixture can be maintained and the processing can be performed for a long time when the adhesive layer is applied.

Sectional drawing which shows an example of the laminated body which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a schematic cross-sectional view of a laminate according to an embodiment of the present invention.

  The laminate 10 of the present invention includes an adhesive layer 3 and a sealant layer 4 in this order on a metal foil 2 (a lower side in the figure) as a thin film layer. The adhesive layer 3 is made of a metal alkoxide and an isocyanate compound. Here, the metal foil 2 is laminated | stacked on the base material 1 (lower side in a figure). Another adhesive layer (not shown) may be provided between the substrate 1 and the metal foil 2.

  The laminated body 10 of the present invention has the metal foil 2, the adhesive layer 3, and the sealant layer 4 as essential layer structures, and this layer structure may be used as long as the metal foil 2 has sufficient strength to support the laminated body itself. However, the base material 1 may be laminated | stacked on the opposite side (other side) of primer layer etc. formation surfaces of the metal foil 2. FIG.

  As the base material 1, it is only necessary to support the laminate, and for example, a polyester film having a thickness of 12 μm can be used. In the lamination of the base material 1 and the metal foil 2, for example, it can be bonded via an adhesive. By providing the base material 1 on the other surface of the metal foil 2, the laminate 10 can be given appropriate strength and flexibility, and the metal foil 2 can be prevented from being damaged or corroded.

  As the metal foil 2, for example, an aluminum foil can be used. The metal foil 2 may be subjected to surface treatment such as corona treatment, low pressure plasma treatment, atmospheric pressure plasma treatment, flame treatment, ion bombardment treatment, and chemical treatment as a pretreatment to improve the wettability of the coating liquid. Alternatively, surface treatment such as solvent treatment may be performed.

  Further, as the thin film layer provided on the substrate 1, an inorganic oxide vapor-deposited film may be used instead of the metal foil 2, and examples of the oxide include aluminum oxide, silicon oxide, magnesium oxide, tin oxide, and the like. In particular, aluminum oxide and silicon oxide are preferable from the viewpoint of oxygen permeability.

  An adhesive layer 3 is laminated on the metal foil 2 by application, for example. The preferable thickness of the adhesive layer 3 is not less than 0.1 μm and not more than 1.0 μm, more preferably about 0.5 μm.

  The material for the adhesive layer 3 is selected to contain a metal alkoxide. Metal alkoxide is a general term for compounds in which hydrogen in the hydroxy group of an alcohol is replaced with a metal. Since the metal alkoxide has both a functional group site that adheres to the resin and a functional group site that adheres to the metal, the metal alkoxide firmly bonds between the metal foil layer and the resin composition (such as an isocyanate compound or a resin composition of a sealant layer). I can do it.

  The metal alkoxide contained in the adhesive layer 3 contains a metal. As the metal contained in the metal alkoxide, silicon, aluminum, titanium, or zirconium can be used. Although there are various metal alkoxides, silicon alkoxides can be more preferably used in consideration of handling property, cost, and the like, and silane coupling agents are most preferable. As the silane coupling agent, a silane coupling agent containing an amino group or the like is suitable.

  The metal alkoxide used as the adhesive layer 3 reacts with a part of the molecule that bonds with a metal such as aluminum on the metal foil 2 side and a resin laminated as an isocyanate or sealant layer 4 in the component of the adhesive layer 3. Functional group. Therefore, it is possible to form a strong bond between the metal foil 2 and the isocyanate component of the adhesive layer 3. In particular, in a silane coupling agent containing an amino group, it is possible to form a urea bond with an isocyanate to obtain a stronger bond.

  Due to the strong bond obtained by providing an adhesive layer 3 containing a metal alkoxide between the metal foil 2, volatile substances such as fragrances, medicinal components and alcohols, surfactants, acidic substances, Even when a strongly permeable article containing an alkaline substance or the like acts on the laminate of the present invention, the cohesive force on the interface between the adhesive layer 3 and the metal foil 2 does not decrease, and the metal foil 2 and the sealant layer 4 The strength of the laminate is reduced, and the initial strength and the resistance to the strongly permeable article are both provided.

  Since the adhesive layer 3 containing a metal alkoxide and an isocyanate has good reactivity as described above, a precipitate is formed when a long time has elapsed after mixing. Therefore, the alkoxyl group of the metal alkoxide needs to have 2 or more carbon atoms, and generally has an ethoxy group that is ethanol and a propoxy group that is propanol which are generally distributed. As the number of alkoxyl group molecules increases, the alcohol is less likely to be removed, and it takes time for the hydrolysis reaction of the metal alkoxide to occur. Therefore, it is possible to prevent polymerization between silane coupling agents generated by hydrolysis and reaction with isocyanate caused by generation of hydroxyl groups.

  The isocyanate compound contained in the adhesive layer 3 is a compound having an isocyanate group in its molecule. Examples of such compounds include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-diphenylmethane diisocyanate, and hydrogenated products thereof. Specific examples include various diisocyanate monomers. Among these, a bifunctional isocyanate monomer (diisocyanate) having two isocyanate groups in the molecule is preferable.

  In addition, adduct (addition product) type obtained by reacting these diisocyanate monomers with trifunctional active hydrogen-containing compounds such as trimethylolpropane and glycerol, biuret type obtained by reacting with water, and self-polymerization of isocyanate groups. A trifunctional diisocyanate derivative such as a trimer (isocyanurate) type used or a polyfunctional derivative higher than that is also preferred.

  In the present invention, the metal alkoxide and the isocyanate are not applied, but are mixed and made into one solution, thereby reducing the cost by simplifying the processing, reducing the overall layer thickness, and between the metal alkoxide and the isocyanate. By promoting the reaction, there is an advantage that strength and tolerance can be improved.

  A sealant layer 4 is laminated on the adhesive layer 3 by, for example, T-die extrusion. The material constituting the sealant layer 4 is a layer made of polyethylene resin or polypropylene resin. Specifically, ethylene resins such as high density polyconylene, low density polyethylene, medium density polyethylene, ethylene-α olefin copolymer, homo-block / random polypropylene resins, propylene-α olefin copolymer, etc. Propylene resins, ethylene-α, β unsaturated carboxylic acid copolymers such as ethylene-acrylic acid copolymer and ethylene-methacrylic acid copolymer, ethylene-methyl acrylate, ethylene-ethyl acrylate, ethylene-methacrylic acid Esterified products of ethylene-α, β unsaturated carboxylic acid copolymers such as methyl acrylate and ethylene-ethyl methacrylate, ethylene-α, β unsaturated carboxylic acid copolymer with carboxylic acid moiety cross-linked with sodium ion and zinc ion Ionic cross-linked products, ethylene-maleic anhydride graft copolymer, Selected from acid anhydride-modified polyolefins typified by terpolymers such as ethylene-ethyl acrylate-maleic anhydride, epoxy compound-modified polyolefins such as ethylene-glycidyl methacrylate copolymers, and ethylene-vinyl acetate copolymers For example, a single resin or a blend of two or more resins may be used. To these constituent materials, various additives (such as an antioxidant, a tackifier, a filler, and various fillers) may be added as necessary.

  Moreover, the laminated body 10 of this invention may form other layers other than metal foil (or inorganic oxide vapor deposition film) layer / adhesion layer / sealant layer. By forming other layers, it is possible to improve the rigidity and durability required for the packaging material in consideration of the use as the packaging material.

  For example, it may be a laminate in which a base material layer / a base material adhesive layer / a metal foil (or inorganic oxide vapor deposition film) layer / an adhesive layer / a sealant layer are laminated in this order. By providing a base material layer on the other surface of the metal foil (or inorganic oxide vapor deposition film) layer, the laminate is given appropriate strength and flexibility, and the metal foil (or inorganic oxide vapor deposition film) layer is provided. Can prevent damage and corrosion. At this time, a film resin such as polyester, nylon, or polypropylene may be used as the base material layer.

  Examples of the present invention will be described below.

<Example 1>
First, the base material layer and the metal foil layer (thin film layer) were laminated with a dry laminator through a base material adhesive.

  At this time, a polyester film (thickness: 12 μm) was used as the base material layer. The metal foil layer was an aluminum foil (thickness = 7 μm). In addition, a two-component curable urethane adhesive was used as the base adhesive.

  Next, a liquid mixed composition is applied to the outer surface of the metal foil layer in the laminate in which the base material layer / the base material adhesive layer / the metal foil layer are laminated in this order by using an extrusion laminator and bonded. A layer was formed.

  At this time, the thickness of the adhesive layer was 0.5 μm. The composition of the mixed composition used for the adhesive layer is shown below.

(Example 1 = mixed composition)
Isocyanate-based silane coupling agent ethoxy group: 0.5 parts by mass Hexamethylene diisocyanate (HDD) burette: 5 parts by mass Ethyl acetate: 95 parts by mass Next, substrate layer / substrate adhesive layer / metal foil layer / adhesive layer However, the resin composition was laminated on the adhesive layer in the laminate laminated in this order by a T-die extrusion method to form a sealant layer.

  At this time, low-density polyethylene was used as a resin composition to be a sealant layer. The sealant layer had a thickness of 20 μm. Further, the printing plate was idled for 8 hours before processing, and the appearance of the mixture was confirmed. As described above, the metal foil layer and the sealant layer are fixed through the adhesive layer, and the base material layer / base material adhesive layer / metal foil layer / adhesive layer / sealant layer are laminated in this order. Got the body.

<Example 2>
A laminate was produced in the same manner as in Example 1. However, the following composition was used for the mixed composition in the adhesive layer.

(Example 2 = mixed composition)
Isocyanate-based silane coupling agent propoxy group: 0.5 parts by mass Hexamethylene diisocyanate (HDI) burette: 5 parts by mass Ethyl acetate: 95 parts by mass <Example 3>
A laminate was produced in the same manner as in Example 1. However, the thin film layer was an alumina vapor-deposited film, the polyester base material was 12 μm, and the mixed composition in the adhesive layer had the following composition.

(Example 3 = mixed composition)
Amino-based silane coupling agent ethoxy group 3.2 parts by mass Hexamethylene diisocyanate (HDI) burette 5 parts by mass ethyl acetate 95 parts by mass <Reference Example 1>
A laminate was produced in the same manner as in Example 1. However, the metal alkoxide in the adhesive layer was a methoxy group.

(Reference Example 1 = mixed composition)
Isocyanate-based silane coupling agent Methoxy group: 0.5 parts by mass Hexamethylene diisocyanate (HDI) burette: 5 parts by mass Ethyl acetate: 95 parts by mass <Reference Example 2>
A laminate was produced in the same manner as in Example 3. However, the metal alkoxide in the adhesive layer was a methoxy group.

(Reference Example 2 = mixed composition)
Amino-based silane coupling agent ethoxy group 3.2 parts by weight Hexamethylene diisocyanate (HDI) burette 5 parts by weight ethyl acetate 95 parts by weight Obtained in Examples 1 to 3 and Reference Examples 1 to 2 The laminate was measured for interlayer laminate strength [N / 15 mm]. At this time, the measurement conditions of the interlayer laminate strength were T-type peeling with a sample width of 15 mm and a peeling speed of 300 mm / min. The results are shown in Table 1 as [Initial Strength].

Moreover, about the laminated body obtained in Example 1-Example 3 and Reference Example 1-Reference Example 2, interlayer lamination strength [N / 15mm] was measured after the accelerated deterioration test. At this time, the measurement conditions of the interlayer laminate strength were T-type peeling with a sample width of 15 mm and a peeling speed of 300 mm / min. The accelerated deterioration test conditions were as follows: (1) the laminate was left to stand in a 50 ° C environment for 3 days, (2) a packaging bag was prepared with the sealant layer of the laminate inside, and (3) the packaging The bag was filled with a solid bath containing a volatile fragrance component as a strong permeable substance and sealed. (4) The packaging bag filled with the solid bath was left in a thermostatic chamber at 40 ° C. for one month. . The results are shown in Table 1 as [strength after test].

  As shown in Table 1, when the strengths of Examples 1 to 3 and Reference Examples 1 and 2 are compared, the initial interlayer laminate strength is sufficiently high with the same strength, and the interlayer laminate strength is hardly reduced even after the test. It was not seen. However, when the appearance of the mixture was confirmed, precipitation occurred in the reference example, and the example did not change.

  From these results, it was confirmed that the laminate of the present invention can withstand long-time processing since it has sufficient strength against a strong osmotic substance and no precipitate is observed.

  The laminate of the present invention is expected to be used in a wide range of fields as a packaging material used for the purpose of holding so as not to be affected by the surrounding environment. For example, it is expected to be used as a packaging material for foods, medical products, precision electronic parts, chemicals, and the like.

DESCRIPTION OF SYMBOLS 1 ... Base material 2 ... Metal foil 3 ... Adhesive layer 4 ... Sealant layer 10 ... Laminated body

Claims (10)

  A laminate comprising at least an adhesive layer and a sealant layer in this order on a substrate, wherein the adhesive layer comprises a metal alkoxide and an isocyanate compound.   The laminated body according to claim 1, wherein a thin film layer made of a metal foil or an inorganic oxide vapor deposition film is provided on the base material, and the adhesive layer is provided on the thin film layer.   The laminate according to claim 1 or 2, wherein the sealant layer is made of either a polyethylene resin or a polypropylene resin.   The laminate according to any one of claims 1 to 3, wherein the metal alkoxide includes any of silicon, aluminum, titanium, and zirconium.   The laminate according to any one of claims 1 to 4, wherein the metal alkoxide is an alcohol having an alkoxyl group having 2 or more carbon atoms.   The laminate according to any one of claims 1 to 5, wherein the metal alkoxide is a silane coupling agent.   The laminate according to claim 6, wherein the silane coupling agent is a silane coupling agent having an amino group.   The isocyanate compound is either a bifunctional isocyanate monomer or a bifunctional isocyanate monomer adduct, biuret compound, isocyanurate or adduct, burette, or a derivative of a trifunctional monomer of the isocyanurate type. The laminate according to any one of claims 1 to 7.   The laminate according to any one of claims 1 to 8, wherein the adhesive layer has a thickness of 1 µm or less.   The packaging material using the laminated body in any one of Claims 1 thru | or 9.

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