JP2020041103A - Two-component adhesive, laminated film and package - Google Patents

Abstract

An object of the present invention is to provide a two-part adhesive having an excellent curing speed and having a very small amount of unintentional substances eluted into the contents through a laminated film when used as a two-part adhesive.
SOLUTION: This composition has a polyol component A containing a polyol compound and an isocyanate component B containing an isocyanate compound, wherein the isocyanate component B is 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, and A two-part adhesive containing at least one diphenylmethane diisocyanate monomer selected from the group consisting of 2,2'-diphenylmethane diisocyanate and polymethylene polyphenylene isocyanate, and having an isocyanate group content of less than 33% by mass. Laminated film, package [selection diagram] None

Description

  The present invention relates to a two-component adhesive, a laminated film and a package using the same.

  Laminated films (sometimes referred to as laminated films) used for various packaging materials, labels, and the like are made of various kinds of plastic films, metal foils, papers, and the like, and are designed, functionally, storable, and convenient. A package provided with transportability, and particularly formed by forming the laminated film into a bag shape, is used as a package for foods, pharmaceuticals, detergents, and the like.

  Conventionally, an adhesive dissolved in a volatile organic solvent (sometimes called a solvent-type laminating adhesive) is applied to the film, and the organic solvent is volatilized in the process of passing through an oven. The mainstream is the one obtained by the dry lamination method in which the films are bonded, but in recent years, from the viewpoint of reducing the environmental load and improving the working environment, a reactive two-component type laminating adhesive containing no volatile organic solvent. Demand for agents (sometimes referred to as two-component adhesives or solventless laminating adhesives) is increasing. (For example, see Patent Document 1)

  Although the two-component adhesive described in Patent Document 1 is effective in reducing the adhesive strength and aging time in the solventless adhesive, the aromatic isocyanate as a curing agent and the polyester diol as a main agent are combined, The resin for the solventless adhesive had a relatively short pot life. If the pot life is short, variations in the amount of coating are likely to occur, resulting in the appearance of the laminate being significantly impaired. Work is required, and workability may be significantly impaired. In particular, when 4,4′-diphenylmethane diisocyanate (MDI), which is one of aromatic isocyanates, is used as a curing agent, the curing agent itself may be crystallized or precipitated because the compound has high crystallinity. .

  Furthermore, since the two-component adhesive uses a reactive monomer having a slightly lower molecular weight than the solvent-type laminate adhesive as a raw material, there is a possibility that the two-component adhesive is eluted into the contents through the laminated film. In particular, in recent years, regulations on components that elute (migrate) chemical substances from plastic containers have been finely defined, particularly in Europe, and there has been a demand for products with a small amount of chemical substances eluted from containers. In the elution of chemical substances generally used in adhesives, SML (Specific Migration Limit) is defined, and the eluted material can be easily controlled, but unintentional additive (NIAS) generated by synthesis or the like can be used. Elution is a problem that cannot be easily cleared.

  On the other hand, an isocyanate-terminated polyurethane resin which is a reaction product with a modified diphenylmethane diisocyanate (MDI) selected from the group consisting of carbodiimide-modified diphenylmethane diisocyanate, allophanate-modified diphenylmethane diisocyanate, biuret-modified diphenylmethane diisocyanate, polymer diphenylmethane diisocyanate and a combination thereof. It is known that an adhesive containing a polymer and a polyol is an adhesive that produces a low concentration of extractable primary aromatic amine (PAA) (for example, see Patent Document 2).

JP 2014-159548 A JP 2014-516321 A

  The problem to be solved by the present invention is to provide a two-part adhesive having an excellent curing rate and a very small amount of unintentional substances eluted into the contents through a laminated film when used as a two-part adhesive. To provide.

  The present inventors have found that a two-part adhesive using only crude MDI as an isocyanate component can solve the above-mentioned problems.

That is, the present invention has a polyol component A containing a polyol compound, and an isocyanate component B containing an isocyanate compound,
The isocyanate component B is a mixture of at least one diphenylmethane diisocyanate monomer selected from the group consisting of 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, and 2,2′-diphenylmethane diisocyanate, and polymethylene polyphenylene isocyanate. Provided is a two-part adhesive containing an isocyanate group content of less than 33% by mass.

  Further, the present invention is a laminated film obtained by laminating an adhesive layer between a first plastic film and a second plastic film, wherein the adhesive layer is a two-component adhesive layer as described above. Provide a laminated film.

  Further, the present invention is a package formed by molding a laminated film obtained by laminating an adhesive layer between a first plastic film and a second plastic film into a bag shape, wherein the adhesive layer is the above-mentioned. And a package which is a layer of the two-component adhesive.

  The two-part adhesive of the present invention has an excellent curing rate and a very small amount of unintentional substances that elute into the contents through the film after lamination. Even after the lapse of time, it is possible to obtain a laminate having excellent adhesion and content resistance without causing peeling of the laminate structure such as delamination.

(Definition of solvent)
The two-part adhesive of the present invention is a reactive two-part type laminating adhesive as described above, and does not use a conventional volatile organic solvent. Also referred to as a laminating adhesive.
In the present invention, an adhesive that is cured by a chemical reaction between an isocyanate group and a hydroxyl group is used. The “solvent” of the solventless adhesive according to the present invention refers to a highly soluble and volatile organic solvent capable of dissolving the polyisocyanate or the polyol used in the present invention. "Means not containing these highly soluble organic solvents. Specific examples of highly soluble organic solvents include toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, and xylol. , N-hexane, cyclohexane and the like. Among them, toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, and ethyl acetate are known as organic solvents having particularly high solubility.

On the other hand, when there is a demand for a low viscosity or the like, the adhesive of the present invention may be appropriately diluted with the highly soluble organic solvent according to a desired viscosity before use. In that case, either one of the polyol component A and the isocyanate component B may be diluted, or both may be diluted. Examples of the organic solvent used in such a case include methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, xylol, n-hexane, cyclohexane and the like. . Among these, ethyl acetate and methyl ethyl ketone (MEK) are preferable from the viewpoint of solubility, and ethyl acetate is particularly preferable. The amount of the organic solvent used depends on the required viscosity, but is often used in the range of about 0.1 to 10% by mass.
Further, in order to achieve a low viscosity of the adhesive of the present invention, a solvent having a carbonyl group having no hydroxyl group and having a boiling point of 200 ° C. or more, such as triacetin and propylene carbonate, may be used. The amount of the organic solvent having a high boiling point depends on the required viscosity and physical properties of the coating film, but is generally used in the range of about 0.1 to 10% by mass.

(Definition of words main agent, curing agent)
In general, there are various expressions for "two-component" in a two-component adhesive, but in the present invention, an isocyanate component B containing an isocyanate compound is called a "curing agent" and a polyol containing a polyol compound is used. Component A is referred to as "base agent".

(Polyol component A containing main compound polyol compound)
As the polyol compound contained in the polyol component A, which is the main component in the present invention, a known polyol can be used without any particular limitation. For example, selected from polyester polyols, polyether polyols, polyurethane polyols, polyether ester polyols, polyester (polyurethane) polyols, polyether (polyurethane) polyols, polyester amide polyols, acrylic polyols, polycarbonate polyols, polyhydroxyalkanes, castor oil, or mixtures thereof. Polymer polyols.

  As the polyester polyol, for example, terephthalic acid, isophthalic acid, adipic acid, azelaic acid, dibasic acids such as sebacic acid or a dialkyl ester thereof or a mixture thereof, for example, ethylene glycol, propylene glycol, diethylene glycol, butylene glycol, neo Glycols such as pentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3′-dimethylolheptane, polyoxyethylene glycol, polyoxypropylene glycol, and polytetramethylene ether glycol; Ring opening weight of lactones such as polyester polyol or polycaprolactone, polyvalerolactone, poly (β-methyl-γ-valerolactone) obtained by reacting with these mixtures. Polyester polyols obtained in combination.

  As the polyether polyol, for example, ethylene oxide, propylene oxide, butylene oxide, an oxirane compound such as tetrahydrofuran, for example, water, ethylene glycol, propylene glycol, trimethylolpropane, a low-molecular-weight polyol such as glycerin is polymerized as an initiator. And the resulting polyether polyols. Examples of the polyether ester polyol include, for example, terephthalic acid, isophthalic acid, adipic acid, azelaic acid, dibasic acids such as sebacic acid or a dialkyl ester thereof, or a mixture thereof, and a polyether polyol obtained by reacting the above. Ether ester polyols may be mentioned.

  The polyurethane polyol is a polyol having a urethane bond in one molecule, for example, a reaction product of a polyether polyol having a number average molecular weight of 200 to 20,000 and an organic polyisocyanate, and NCO / OH is preferably less than 1, More preferably, it is 0.9 or less. As the organic polyisocyanate, a polyisocyanate compound described below, in particular, a diisocyanate compound can be used.

  Polyether (polyurethane) polyols and polyester (polyurethane) polyols are reaction products of polyester polyols, polyetherester polyols and the like with organic polyisocyanates, and preferably have an NCO / OH of less than 1, more preferably 0.9 or less. Can be mentioned.

The polyesteramide polyol can be obtained by using an aliphatic diamine having an amino group such as ethylenediamine, propylenediamine, or hexamethylenediamine as a raw material in the esterification reaction.
Examples of the acrylic polyol include hydroxyethyl acrylate, hydroxypropyl acrylate, acrylhydroxybutyl and the like containing one or more hydroxyl groups in one molecule, or their corresponding methacrylic acid derivatives, and, for example, acrylic acid and methacrylic acid. It is obtained by copolymerizing an acid or an ester thereof.

  Examples of the polycarbonate polyol include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, and 1,9-nonane. Diol, 1,8-nonanediol, neopentyl glycol, diethylene glycol, dipropylene glycol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, bisphenol A, one selected from hydrogenated bisphenol A or Examples include those obtained by reacting two or more glycols with dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, or the like.

Examples of the polyhydroxyalkane include butadiene or a liquid rubber obtained by copolymerizing butadiene with acrylamide.
Among them, polyether (polyurethane) polyol is particularly preferred.

  As the polyol compound used in the present invention, a reaction product of a polyisocyanate and a bis (hydroxyalkyl) amine having a urea bonding group at a terminal can also be preferably used.

  The number average molecular weight of the polyol component A is not particularly limited, but is usually adjusted in the range of 500 to 3,000 from the viewpoint of appropriate resin viscosity at the time of coating.

  In the present invention, the number average molecular weight (Mn) is a value measured by gel permeation chromatography (GPC) under the following conditions.

Measurement device: Tosoh Corporation HLC-8220GPC
Column: Tosoh Corporation TSK-GUARDCOLUMN SuperHZ-L
+ TSK-GEL SuperHZM-M x 4 manufactured by Tosoh Corporation
Detector: RI (differential refractometer)
Data processing: Tosoh Corporation Multi-station GPC-8020 model II
Measurement conditions: Column temperature 40 ° C
Solvent Tetrahydrofuran
Flow rate: 0.35 ml / min Standard: Monodispersed polystyrene sample: 0.2% by mass of resin in solid tetrahydrofuran solution filtered through a microfilter (100 μl)

(Curing agent Isocyanate component B containing isocyanate compound)
The isocyanate component B which is a curing agent in the present invention is crude MDI, that is, at least one kind selected from the group consisting of 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, and 2,2′-diphenylmethane diisocyanate. An isocyanate component containing diphenylmethane diisocyanate monomer and polymethylene polyphenylene isocyanate and having an isocyanate group content of less than 33% by mass is used.

The isocyanate group content of crude MDI is calculated as follows.
[NCO (% by mass)]
Approximately 1 g of isocyanate component B is precisely weighed in a 200 mL Erlenmeyer flask, 10 mL of 0.5 N di-n-butylamine (toluene solution), 10 mL of toluene and an appropriate amount of bromophenol blue are added, and then about 100 mL of methanol is added and dissolved. . The mixture is titrated with a 0.25N hydrochloric acid solution. NCO (% by mass) is determined by the following equation.

  Commercial products of Crude MDI are available from Yantai Wanhua, BASF IN @ AC Polyurethane Co., Ltd., and include Wannanate PM-200 manufactured by Yantai Wanhua, Luplanate M20S manufactured by BASF IN @ AC Polyurethane Co., Ltd., and the like.

  The polymethylene polyphenylene isocyanate contained in 100% by mass of crude MDI used in the present invention is preferably 50 to 70% by mass. When the polymethylene polyphenylene isocyanate content is within the above range, a laminate having a better appearance can be obtained when a film substrate having high gas barrier properties is used and applied and bonded at high speed.

  The mixing ratio of the polyol component A containing the polyol compound and the isocyanate component B containing the isocyanate compound is the equivalent of the hydroxyl equivalent of the solid content of the polyol compound (a) and the isocyanate equivalent of the solid content of the polyisocyanate compound (b). The ratio [(a) / (b)] is 1.0 to 5.0, more preferably 2.0 to 3.0. Details of the manufacture are described in the examples.

(viscosity)
It is preferable that the two-component adhesive of the present invention has a viscosity of 5000 mPa · s or less after the polyol component A and the isocyanate component B are blended at a weight ratio and left for 30 minutes in a 40 ° C. atmosphere. In the present invention, the viscosity is a value measured by a rotational viscometer under the following conditions.
Measuring device: MCR-302 manufactured by Anton Paar
Measurement conditions: temperature 40 ° C, cone plate Φ50mm

  The viscosity is preferably in the range of 500 to 5000 mPa · s, and more preferably in the range of 1500 to 4500 mPa · s.

  As described in detail, the two-part adhesive of the present invention contains the polyol component A and the isocyanate component B as essential components. Further, the aliphatic cyclic amide compound is further combined with the polyol component A and the isocyanate component B. By mixing with either one of these components, or blending it as a third component at the time of application, the elution of harmful low-molecular-weight chemicals represented by aromatic amines into the contents in the laminate package is effective. Can be suppressed.

  Examples of the aliphatic cyclic amide compound used here include δ-valerolactam, ε-caprolactam, ω-enanthol lactam, η-caprylactam, β-propiolactam and the like. Among them, ε-caprolactam is preferable because of its excellent effect of reducing the amount of low-molecular-weight chemical substance eluted. Moreover, it is preferable to mix the aliphatic cyclic amide compound in the range of 0.1 to 5 parts by mass per 100 parts by mass of the polyol component A.

  The two-part adhesive of the present invention may use a pigment, if necessary. The pigment that can be used in this case is not particularly limited. For example, extenders, white pigments, black pigments, gray pigments, and red pigments described in the 1970 Handbook of Paint Materials (edited by the Japan Paint Manufacturers Association) Examples of the pigment include organic pigments and inorganic pigments such as pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, and pearlescent pigments, and further, plastic pigments. Specific examples of these colorants include various pigments. Examples of organic pigments include various insoluble azo pigments such as benzidine yellow, Hansa yellow, and Lake 4R; and solubility of lake C, carmine 6B, Bordeaux 10 and the like. Azo pigments; various (copper) phthalocyanine pigments such as phthalocyanine blue and phthalocyanine green; various chlorinated dyeing lakes such as rhodamine lake and methyl violet lake; various mordant dye pigments such as quinoline lake and fast sky blue; anthraquinone Pigments, thioindigo pigments, perinone pigments, etc .; various vat dye pigments; various quinacridone pigments, such as Synchasia Red B; various oxazine pigments, such as oxazine violet; Pigment; aniline black, etc. And the like.

  Examples of the inorganic pigments include various chromates such as graphite, zinc chromate and molybdate orange; various ferrocyan compounds such as navy blue; titanium oxide, zinc white, mapico yellow, iron oxide, red iron oxide, chrome oxide Various metal oxides such as green and zirconium oxide; various sulfides or selenides such as cadmium yellow, cadmium red and mercury sulfide; various sulfates such as barium sulfate and lead sulfate; various types of calcium silicate and ultramarine blue Various carbonates such as calcium carbonate and magnesium carbonate; Various phosphates such as cobalt violet and manganese purple; Various metal powders such as aluminum powder, gold powder, silver powder, copper powder, bronze powder and brass powder Pigments; flake pigments of these metals, mica flake pigments; mica flakes coated with metal oxide Pigments, metallic pigments and pearl pigments such as micaceous iron oxide pigments; graphite, carbon black and the like.

  As the extender pigment, for example, precipitated barium sulfate, powder, precipitated calcium carbonate, calcium bicarbonate, dolomite, alumina white, silica, hydrated fine powdered silica (white carbon), ultrafine powdered anhydrous silica (Aerosil), silica sand (silica) Sand), talc, precipitated magnesium carbonate, bentonite, clay, kaolin, loess and the like.

  Further, examples of the plastic pigment include "Grandol PP-1000" and "PP-2000S" manufactured by DIC Corporation.

  As the pigment used in the present invention, inorganic oxides such as titanium oxide and zinc white as a white pigment, and carbon black as a black pigment are more preferable because of excellent durability, weather resistance and design.

  The mass ratio of the pigment used in the present invention is, with respect to 100 parts by mass of the total of the isocyanate component B and the polyol component A, from 1 to 400 parts by mass, preferably from 10 to 300 parts by mass, such as adhesion and blocking resistance. It is more preferable because it is excellent.

  The two-part adhesive of the present invention can also use an adhesion promoter. Examples of the adhesion promoter include a silane coupling agent, a titanate-based coupling agent, an aluminum-based coupling agent, and an epoxy resin.

  Examples of the silane coupling agent include γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-β (aminoethyl) -γ-aminopropyltrimethoxysilane, and N-β (aminoethyl) -γ Aminosilanes such as -aminopropyltrimethyldimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane; β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-gly Epoxysilanes such as sidoxypropyltriethoxysilane; vinylsilanes such as vinyltris (β-methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane; hexamethyldisilazane, γ-mel Hept trimethoxysilane and the like.

  Examples of titanate-based coupling agents include, for example, tetraisopropoxytitanium, tetra-n-butoxytitanium, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctylene glycol titanate, titanium lactate, and tetrastearoxy. Titanium and the like can be mentioned.

  Examples of the aluminum-based coupling agent include, for example, acetoalkoxyaluminum diisopropylate.

  Examples of the epoxy resin include generally commercially available bisphenol-type epoxy resins, novolak-type epoxy resins, β-methylglycidyl ether of bisphenol, β-methylglycidyl ether of novolak resins, cyclic oxirane-type epoxy resins, resorcinol-type epoxy resins, and the like. Of various epoxy resins.

  If necessary, the two-component adhesive used in the present invention may contain other additives other than those described above. Examples of the additive include a leveling agent; inorganic fine particles such as colloidal silica and alumina sol; organic fine particles of polymethyl methacrylate; an antifoaming agent; a sagging inhibitor; a wetting and dispersing agent; Deactivator; Peroxide decomposer; Flame retardant; Reinforcing agent; Plasticizer; Lubricant; Rust inhibitor; Fluorescent brightener; Inorganic heat ray absorber; Flame retardant; Antistatic agent; Is mentioned.

  These pigments, adhesion promoters, and additives can be mixed with either one of the isocyanate component B and the polyol component A, or can be used as a third component by being compounded during coating. Among these, it is possible to prepare a premix in which a pigment, an adhesion promoter, and an additive are previously blended with a polyol component A as a polyol composition for a laminate adhesive of the present invention, and to use it as a two-part adhesive. It is preferable from the viewpoint of workability.

(Laminated film)
The laminated film of the present invention is obtained by laminating an adhesive layer composed of the two-component adhesive between a first plastic film and a second plastic film. Specifically, it is obtained by applying the two-part adhesive to a first plastic film, then laminating a second plastic film on the applied surface, and curing the adhesive layer. For example, there is a method in which the two-component adhesive is applied to a first plastic film by a roll coater coating method, and then, another substrate is bonded without passing through a drying step. The coating conditions are such that, with a normal roll coater, the viscosity of the adhesive mixture is preferably about 300 to 3000 mPa · s at 40 ° C. while being heated to 30 ° C. to 90 ° C., but the adhesive of the present invention is not mixed. Since the viscosity after leaving for 30 minutes in an atmosphere of 40 ° C. is 5000 mPa · s or less, coating can be performed without any problem. Further, the coating amount is preferably 0.5 to 5 g / m ² , and more preferably about 0.5 to 3 g / m ² .

  In addition, a gravure or flexo-printed printing ink may be used on the first plastic film. Even in this case, a good laminate appearance can be exhibited. As the above-mentioned printing ink, a solvent type, aqueous type or active energy ray curable type ink can be used.

  When the two-component adhesive used in the present invention is used, after laminating, the adhesive cures at room temperature or under heating for 12 to 72 hours, and exhibits practical physical properties.

  As the first plastic film used herein, a PET (polyethylene terephthalate) film, a nylon film, an OPP (biaxially oriented polypropylene) film, a K coat film such as polyvinylidene chloride, a base film such as various vapor deposition films, and an aluminum foil. Examples of the second plastic film include, as the other substrate, a CPP (unstretched polypropylene) film, VMCPP (aluminum-deposited unstretched polypropylene film), LLDPE (linear low-density polyethylene), LDPE (Low-density polyethylene), HDPE (high-density polyethylene), and sealant films such as VMLDPE (aluminum-deposited low-density polyethylene film) films.

  In the present invention, an excellent laminated film appearance can be obtained even by high-speed laminating with a solventless laminating machine. For example, in the case of a PET (polyethylene terephthalate) film / VMCPP (aluminum-deposited unstretched polypropylene film) film structure A good appearance can be exhibited even at a high speed processing of 200 m / min or more, and in the case of an OPP / CPP film configuration of 350 m / min or more.

(Package)
The package of the present invention is formed by molding the laminated film into a bag shape. Specifically, the package is formed by heat-sealing the laminated film. In addition, when considering the use as a package, required performance (easy tearing property and hand-cutting property), rigidity and durability required for the package (for example, impact resistance and pinhole resistance, etc.), Other layers can be laminated as needed. Usually, it is used with a base material layer, a paper layer, a second sealant layer, a non-woven cloth layer and the like. As a method of laminating another layer, a known method can be used. For example, an adhesive layer may be provided between other layers and laminated by a dry lamination method, a heat lamination method, a heat sealing method, an extrusion lamination method, or the like. As the adhesive, the above-mentioned two-component adhesive may be used, or another one-component type urethane-based adhesive, epoxy-based adhesive, aqueous dispersion of acid-modified polyolefin, or the like may be used.

  Specific laminate structures include a first plastic film layer / adhesive layer / second plastic layer, and a first plastic layer, which can be suitably used for general packaging, lid materials, refill containers, and the like. Base layer / adhesive layer / first plastic film layer / adhesive layer / second plastic layer / paper which can be suitably used for paper containers, paper cups, etc. Layer / adhesive layer / first plastic film layer / adhesive layer / second plastic, second plastic layer / paper layer / polyolefin resin layer / substrate layer / first plastic layer / adhesive layer / second plastic Layer, paper layer / first plastic film layer / adhesive layer / sealant layer, second plastic layer / adhesive layer / first plastic which can be suitably used for tube containers, etc. Such as a layer / adhesive layer / second plastic layer. These laminates may have a print layer, a top coat layer, and the like, if necessary.

  The first plastic film layer includes, for example, a polyester resin film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), and polylactic acid (PLA); a polyolefin resin film such as polypropylene; a polystyrene resin film; Polyamide resin film such as p-xylylene adipamide (MXD6 nylon); polycarbonate resin film; polyacrylonitrile resin film; polyimide resin film; a multilayer body of these (for example, nylon 6 / MXD6 / nylon 6, nylon 6 / Ethylene-vinyl alcohol copolymer / nylon 6) or a mixture is used. Among them, those having mechanical strength and dimensional stability are preferable. In particular, among these, films stretched arbitrarily in the biaxial direction are preferably used.

  In addition, the first plastic film layer is formed of a soft metal foil such as an aluminum foil to provide a barrier function, as well as an evaporation layer such as aluminum evaporation, silica evaporation, alumina evaporation, and silica-alumina binary evaporation; An organic barrier layer made of modified polyvinyl alcohol, ethylene vinyl alcohol copolymer, MXD nylon, or the like can be used.

  As the second plastic film layer, a conventionally known sealant resin can be used. For example, polyethylene such as low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and high density polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, copolymerized polypropylene, ethylene-vinyl acetate Examples include copolymers, ethylene- (meth) acrylate copolymers, ethylene- (meth) acrylic acid copolymers, and polyolefin resins such as ionomers. Of these, polyethylene resins are preferred from the viewpoint of low-temperature sealing properties, and polyethylene is particularly preferred because of its low cost. The thickness of the sealant layer is not particularly limited, but is preferably in the range of 10 to 60 μm, and more preferably in the range of 15 to 40 μm, in consideration of workability into a packaging material, heat sealability, and the like. Further, by providing the sealant layer with unevenness having a height difference of 5 to 20 μm, it is possible to impart slipperiness and tearability of the packaging material to the sealant layer.

  Examples of the paper layer include natural paper and synthetic paper. The first and second sealant layers can be formed of the same material as the above-described sealant layer. A printing layer may be provided on the outer surface or the inner surface side of the base material layer and the paper layer as necessary.

  The “other layer” may contain known additives and stabilizers, for example, an antistatic agent, an easy-adhesion coating agent, a plasticizer, a lubricant, an antioxidant, and the like. The “other layer” is obtained by subjecting the film surface to a corona treatment, a plasma treatment, an ozone treatment, a chemical treatment, a solvent treatment, or the like as a pre-treatment in order to improve adhesion when laminated with another material. You may.

  Examples of the package of the present invention include a three-sided seal bag, a four-sided seal bag, a gusset packaging bag, a pillow packaging bag, a bottomed container of a Gebel top type, a tetra-classic, a Bruch type, a tube container, a paper cup, a lid material, and the like. There are various. Further, the package of the present invention may be provided with an easy-opening process or a re-sealing means as appropriate.

  The package of the present invention can be used industrially mainly as a package for filling a food, a detergent, and a medicine. Specific applications include detergents and pharmaceuticals such as laundry liquid detergents, kitchen liquid detergents, bath liquid detergents, bath liquid soaps, liquid shampoos, liquid conditioners, and pharmaceutical tablets. It can also be used for a secondary package for packaging the above container. In particular, since the two-component adhesive is used, it can be suitably used as a package for food and pharmaceutical applications where elution is a problem.

  Next, the present invention will be specifically described with reference to Examples and Comparative Examples. Examples Unless otherwise noted, "parts" and "%" are on a mass basis.

Synthesis Example 1 [Synthesis of polyol component A1]
119 parts by mass of ethylene glycol and 290 parts by mass of diethylene glycol were charged into a reaction vessel and heated to 80 ° C. while stirring under a nitrogen gas stream. Further, while stirring, 590 parts by mass of adipic acid was charged into a reaction vessel and heated to 150 ° C. to 240 ° C. to perform an esterification reaction. When the acid value becomes 5 mgKOH / g or less, the pressure in the reaction vessel is gradually reduced, and the reaction is carried out at 200 to 240 ° C. for 3 hours at 1 mmHg or less, and a polyester polyol having an acid value of 2 mgKOH / g and a molecular weight of about 1350 and having hydroxyl groups at both ends is obtained. A resin (hereinafter, abbreviated as "polyol component A1") was obtained.

Synthesis Example 2 [Synthesis of polyol component A2]
129 parts by mass of ethylene glycol, 137 parts by mass of diethylene glycol, and 303 parts by mass of polypropylene glycol (molecular weight: about 1,000, diol form) were charged into a reaction vessel and heated to 80 ° C. while stirring under a nitrogen gas stream. Further, 106 parts by mass of phthalic anhydride and 324 parts by mass of adipic acid were charged into a reaction vessel while stirring, and heated to 150 ° C. to 220 ° C. to perform an esterification reaction. When the acid value became 8 mgKOH / g or less, the pressure in the reaction vessel was gradually reduced, and the reaction was carried out at 1 mmHg or less at 220 ° C. for 3 hours to obtain a polyester polyether polyol having an acid value of 3 mgKOH / g and a molecular weight of about 1170 and having hydroxyl groups at both ends. A resin (hereinafter, abbreviated as “polyol component A2”) was obtained.

Synthesis Example 3 [Synthesis of polyol component A3]
550 parts by mass of polypropylene glycol (molecular weight: about 3,000, triol form) and 450 parts by mass of castor oil (product name: refined castor oil Kakukoichi, manufactured by Ito Oil Co., Ltd.) are charged into a reaction vessel, and heated to 60 ° C. while stirring under a nitrogen gas stream to be uniform. Dissolved. A polyether castor oil polyol resin having a hydroxyl value of 95 mgKOH / g (hereinafter abbreviated as "polyol component A3") was obtained.

Comparative Synthesis Example 1 [Synthesis of Isocyanate Component C1 as Curing Agent]
200 parts of 4,4'-diphenylmethane diisocyanate, a 50/50 mixture of 2,4-diphenylmethane diisocyanate (product name, manufactured by Luplanate MI BIP), 4,4'-diphenylmethane diisocyanate (product name, manufactured by Millionate MT-F, manufactured by Tosoh Corporation) 339 parts 422 parts of polypropylene glycol (molecular weight: about 1000) and 39 parts of polypropylene glycol (molecular weight: about 400) are charged into a reaction vessel and heated to 80 ° C. while stirring under a stream of nitrogen gas to carry out a reaction. The vessel was cooled to obtain an isocyanate component C2 having an isocyanate group concentration of about 13.6%.

(Example of a two-part adhesive, comparative example)
According to the formulations in Tables 1 and 2, two-part adhesives of Examples 1 to 6 and Comparative Example 1 were obtained.

(Evaluation method)
[Evaluation of harmful component (PAA) elution amount]
The two-component adhesive compounded in the combination of Example or Comparative Example was applied to a PET film so that the applied amount became about 3.0 g / m ^{2 in} solid content, and the coated surface of this film and the LLDPE film were coated with a laminator. To produce a laminated film. This laminated film was stored in a thermostat at 40 ° C. for 3 days.
This laminated film was cut out at 120 mm × 220 mm, bent so that LLDPE was on the inside, and heat-sealed at 1 atm in three directions with a width of 10 mm at 180 ° C. for 1 second to produce a pouch in which the contents were in contact with ² dm ² . . For the contents, a 3% acetic acid vinegar solution was added. After the filled pouch was sterilized by boiling at 98 ° C. for 1 hour, PAA was measured by LC / MS / MS.

[Viscosity measurement at 40 ° C.-30 minutes after compounding]
The viscosity was measured by a rotational viscometer under the following conditions, and the value was mPa · s.
Measuring device: MCR-302 manufactured by Anton Paar
Measurement conditions: temperature 40 ° C, cone plate Φ50mm
The viscosity evaluation was as follows.
Viscosity evaluation 1: 1000 to 3000 mPa · s
Viscosity evaluation 2: 3000 to 4000 mPa · s
Viscosity evaluation 3: 4000 to 5000 mPa · s
Viscosity evaluation 4: 5000 mPa · s or more

[Laminate strength]
A two-component adhesive prepared by combining the examples or comparative examples with a PET film obtained by gravure-printing a pattern using a printing ink Univia NT (manufactured by DIC) so that the applied amount becomes about 3.0 g / m ^{2 of} solid content. Applied. Thereafter, the coated surface of the film and the LLDPE film were bonded by a laminator to produce a laminated film. This laminated film was stored in a thermostat at 40 ° C. for 3 days to prepare a laminated film for a laminate strength test.
A test piece was cut out from the laminated film at a width of 15 mm, and the adhesive strength (N / 15 mm) was measured by T-peeling at a peeling speed of 300 mm / min using a tensile tester.

[Laminate strength and appearance after boiling]
A two-part adhesive prepared by combining the examples or comparative examples with a PET film having a gravure printed pattern with a printing ink (“Univia NT” manufactured by DIC Corporation) was applied at a solid content of 3.0 g / m 2. ^It was applied so as to be about ² . Thereafter, the coated surface of the film and the LLDPE film were bonded by a laminator to produce a laminated film. This laminated film was stored in a thermostat at 40 ° C. for 3 days.
This laminated film was cut into a size of 150 mm × 300 mm, bent so that LLDPE was on the inside, and heat-sealed at 1 atm at 180 ° C. for 1 second to produce a pouch. As the contents, 1/1/1 sauce (meat sauce: vegetable oil: vinegar = 1: 1: 1) was added.
The filled pouch was subjected to boiling sterilization at 98 ° C. for 1 hour. The content was removed, a test piece was cut out from the laminated film at a width of 15 mm, and the adhesive strength (N / 15 mm) was measured by T-type peeling at a peeling speed of 300 mm / min using a tensile tester.
In addition, the appearance of each pouch after removal was observed, and the following evaluation was performed based on the presence or absence of delamination.
Evaluation ：: No delamination Evaluation △: Delamination point 5 points or less Evaluation X: Delamination point 6 points or more

[Curing speed evaluation]
The two-component adhesive compounded in the combination of the example or the comparative example was applied to the plain nylon film so that the applied amount was about 3.0 g / m ^{2 of the} solid content. Thereafter, the coated surface of the film and the LLDPE film were bonded by a laminator to prepare a laminated film.
This laminated film was stored in a constant temperature bath at 40 ° C., and the NCO reaction rate (%) was calculated from the absorbance of the NCO peak on the first, second, and third days using an infrared spectrometer, and cured. A speed evaluation was performed.
The curing speed was evaluated as follows.
Curing rate evaluation 1: NCO conversion rate of 90% or more and curing rate evaluation 2: NCO conversion rate of 70% or more and less than 90% Curing rate evaluation 3: NCO conversion rate of 50% or more and less than 70% Curing rate evaluation 4: NCO conversion rate Is less than 50%

The evaluation results are shown in Tables 1 and 2.

Abbreviations in the table are as follows.
PPG1000 Exenol 1020 manufactured by Asahi Glass Co., Ltd.

As a result, it is clear that the two-part adhesive of the present invention has an excellent curing speed and a very small amount of PAA eluted.

Claims (3)

It has a polyol component A containing a polyol compound and an isocyanate component B containing an isocyanate compound, wherein the isocyanate component B is 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, and 2,2 ′ -A two-part adhesive comprising at least one diphenylmethane diisocyanate monomer selected from the group consisting of diphenylmethane diisocyanate and polymethylene polyphenylene isocyanate, and having an isocyanate group content of less than 33% by mass. A laminated film in which an adhesive layer is laminated between a first plastic film and a second plastic film, wherein the adhesive layer is a layer of the two-component adhesive according to claim 1. Characterized laminated film. 2. A package formed by forming a laminated film obtained by laminating an adhesive layer between a first plastic film and a second plastic film into a bag-like shape, wherein the adhesive layer is formed by the method according to claim 1. A package comprising a liquid adhesive layer.