Method for manufacturing adhesives and method for manufacturing laminates

Abstract

To provide an adhesive and a laminate that exhibit superior gas barrier property and adhesion, and also exhibit superior initial tack.SOLUTION: An adhesive comprises an isocyanate group-terminated prepolymer. The isocyanate group-terminated prepolymer comprises a reaction product of a polyisocyanate component containing xylylene diisocyanate and a polyol component containing a polyester polyol and a low molecular weight diol. The isocyanate group-terminated prepolymer comprises a skeleton represented by structural formula (A). The content ratio of the skeleton represented by structural formula (A) is 40 mass% or more relative to the total amount of the isocyanate group-terminated prepolymer. (In the formula below, X represents a low molecular weight diol residue.)SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to an adhesive and a laminate.

Background Art

[0002] In the field of packaging materials, a laminate in which a plastic film and a gas barrier layer are laminated is known. As the gas barrier layer, for example, a metal vapor deposition layer formed by vapor-depositing a metal layer and / or a metal oxide on a plastic film is known. In recent years, a polyurethane layer has been proposed as the gas barrier layer. It has also been proposed to laminate a polyurethane layer and a metal vapor deposition layer.

[0003] More specifically, for example, the following laminate is known. That is, the laminate includes a film and a gas barrier layer. The gas barrier layer includes a cured product of a gas barrier polyurethane resin composition. The gas barrier polyurethane resin composition includes an agent A and an agent B. Agent A includes an adduct of XDI and TMP. Agent B includes ethylene glycol and ethanol. Furthermore, as the film, a film provided with a metal vapor deposition layer is used (see, for example, Patent Document 1 (Example 13)).

[0004] In the above laminate, the gas barrier layer has excellent gas barrier properties and adhesion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] On the other hand, the gas barrier polyurethane resin composition is further required to have adhesion immediately after coating (initial tack).

[0007] The present invention provides an adhesive and laminate that exhibit excellent gas barrier properties and adhesion, as well as excellent initial tack. [Means for solving the problem]

[0008] The present invention [1] is an adhesive comprising an isocyanate-terminated prepolymer, wherein the isocyanate-terminated prepolymer comprises a reaction product of a polyisocyanate component comprising xylylene diisocyanate and a polyol component comprising a polyester polyol and a low molecular weight diol, and the isocyanate-terminated prepolymer comprises a skeleton represented by structural formula (A), wherein the content of the skeleton represented by structural formula (A) is 40% by mass or more relative to the total amount of the isocyanate-terminated prepolymer.

[0009] [ka] (In the formula, X represents a low molecular weight diol residue.)

[0010] The present invention [2] comprises the adhesive described in [1] above, wherein the low molecular weight diol comprises ethylene glycol and / or propylene glycol.

[0011] The present invention [3] includes the adhesive described in [1] or [2] above, wherein the number average molecular weight of the polyester polyol is 400 or more and 2000 or less.

[0012] The present invention [4] includes a moisture-curing adhesive, as described in any one of the above [1] to [3].

[0013] The present invention [5] is a two-component curing adhesive comprising the adhesive described in any one of the above [1] to [3], which comprises a first liquid containing the isocyanate group-terminated prepolymer and a second liquid containing a low molecular weight polyol.

[0014] The present invention [6] includes the adhesive according to [5] above, in which the content ratio of the skeleton represented by the structural formula (A) is 50% by mass or more with respect to the total amount of the cured product of the two-component curable adhesive.

[0015] The present invention [7] includes a laminate including a substrate, an adhesive layer disposed on the substrate, and an inorganic thin film disposed on the adhesive layer, wherein the adhesive layer is a cured product of the adhesive according to any one of [1] to [6] above.

[0016] The present invention [8] is a two-component curable adhesive including a first liquid containing an isocyanate group-terminated prepolymer and a second liquid containing a low molecular weight polyol. The isocyanate group-terminated prepolymer includes a reaction product of a polyisocyanate component containing xylylene diisocyanate and a polyol component containing a polyester polyol and a low molecular weight diol. The isocyanate group-terminated prepolymer includes a skeleton represented by the structural formula (A), and the content ratio of the skeleton represented by the structural formula (A) is 50% by mass or more with respect to the total amount of the cured product of the two-component curable adhesive.

Chemical formula

Advantages of the Invention

[0017] The adhesive of the present invention includes an isocyanate group-terminated prepolymer. The isocyanate group-terminated prepolymer includes a reaction product of a polyisocyanate component containing xylylene diisocyanate and a polyol component containing a polyester polyol and a low molecular weight diol. Therefore, the adhesive of the present invention has excellent initial tack. Further, the adhesive of the present invention contains the skeleton represented by the above structural formula (A) in the isocyanate group-terminated prepolymer at a ratio of a predetermined value or more. Therefore, the adhesive of the present invention has excellent gas barrier properties and adhesion.

[0018] Further, the adhesive of the present invention contains the skeleton represented by the above structural formula (A) at a ratio of a predetermined value or more with respect to the total amount of the cured product of the two-component curable adhesive. Therefore, the adhesive of the present invention is excellent in gas barrier properties and adhesion.

[0019] The laminate of the present invention includes an adhesive layer which is a cured product of the above adhesive. Further, an inorganic thin film is disposed on the adhesive layer. Therefore, the laminate of the present invention is excellent in the initial tack, gas barrier properties, and adhesion of the adhesive layer.

Brief Description of Drawings

[0020] [Figure 1] FIG. 1 is a schematic configuration diagram of a laminate film as an embodiment of the laminate of the present invention.

Embodiments for Carrying Out the Invention

[0021] The adhesive of the present invention is, although will be described in detail later, a two-component curable adhesive or a moisture curable (one-component curable) adhesive. The adhesive contains an isocyanate group-terminated prepolymer as an essential component.

[0022] The isocyanate group-terminated prepolymer includes a reaction product of a polyisocyanate component and a polyol component. Preferably, the isocyanate group-terminated prepolymer is a reaction product of a polyisocyanate component and a polyol component.

[0023] The polyisocyanate component includes xylylene diisocyanate as an essential component. Examples of xylylene diisocyanate include 1,2-xylylene diisocyanate (o-XDI), 1,3-xylylene diisocyanate (m-XDI), and 1,4-xylylene diisocyanate (p-XDI). These can be used alone or in combination of two or more. Preferably, 1,3-xylylene diisocyanate is mentioned.

[0024] Furthermore, xylylene diisocyanate may be a modified form, to the extent that it does not impair the excellent effects of the present invention. Examples of modified forms include uretdione modified form, isocyanurate modified form, iminooxadiazinedione, biuret modified form, allophanate modified form, polyol adduct, oxadiazinetrione modified form, and carbodiimide modified form.

[0025] The polyisocyanate component may optionally contain other isocyanates. These other isocyanates are isocyanates other than xylylene diisocyanate.

[0026] Other isocyanates include, for example, aliphatic polyisocyanates, alicyclic polyisocyanates, aromatic polyisocyanates, and aromatic aliphatic polyisocyanates (excluding xylylene diisocyanate). Examples of aliphatic polyisocyanates include trimethylene diisocyanate, tetramethylene diisocyanate, pentamethylene diisocyanate (PDI), hexamethylene diisocyanate (HDI), 1,2-propane diisocyanate, 1,2-butane diisocyanate, 2,3-butane diisocyanate, 1,3-butane diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, and 2,6-diisocyanate methyl caproate. Examples of alicyclic polyisocyanates include isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), and methylenebis(cyclohexyl isocyanate) (H 12 Examples include MDI and bis(isocyanatomethyl)cyclohexane (H6XDI). Examples of aromatic polyisocyanates include tolylene diisocyanate (TDI), diphenylmethane diisocyanate (MDI), toluidine diisocyanate (TODI), paraphenylenedi diisocyanate, and naphthalene diisocyanate (NDI). An example of an aromatic aliphatic polyisocyanate is tetramethylxylylene diisocyanate (TMXDI). Other polyisocyanates may be modified versions of those described above, as long as they do not impair the excellent effects of the present invention. These can be used individually or in combination of two or more.

[0027] The content of other isocyanates relative to the total amount of polyisocyanate components is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass. Furthermore, the content of xylylene diisocyanate relative to the total amount of polyisocyanate components is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. In other words, the polyisocyanate component is particularly preferably xylylene diisocyanate.

[0028] The polyol component includes macropolyols and low molecular weight polyols. Preferably, the polyol component consists of macropolyols and low molecular weight polyols.

[0029] Macropolyols are organic compounds with two or more hydroxyl groups in their molecule and a relatively high molecular weight. "Relatively high molecular weight" means a number-average molecular weight of 400 or more.

[0030] Macropolyols contain polyester polyols as an essential component.

[0031] Examples of polyester polyols include polycondensates obtained by reacting a polyhydric alcohol with a polybasic acid under known conditions.

[0032] Examples of polyhydric alcohols include low molecular weight polyols, which will be discussed later. More specifically, examples of polyhydric alcohols include dihydric alcohols, trihydric alcohols, and tetrahydric or higher alcohols, which will be discussed later. These can be used individually or in combination of two or more. From the viewpoint of initial tack, dihydric alcohols are preferred, more preferably ethylene glycol, diethylene glycol, 1,3-butanediol, and neopentyl glycol, and particularly preferred from the viewpoint of initial tack are diethylene glycol, butanediol, and neopentyl glycol.

[0033] Examples of polybasic acids include saturated aliphatic dicarboxylic acids, unsaturated aliphatic dicarboxylic acids, aromatic dicarboxylic acids, alicyclic dicarboxylic acids, other carboxylic acids, acid anhydrides, and acid halides. Examples of saturated aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, methylsuccinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, 3-methyl-3-ethylglutaric acid, azelaic acid, and sebacic acid. Examples of unsaturated aliphatic dicarboxylic acids include maleic acid, fumaric acid, and itaconic acid. Examples of aromatic dicarboxylic acids include orthophthalic acid, isophthalic acid, terephthalic acid, toluenedicarboxylic acid, and naphthalenedicarboxylic acid. Examples of alicyclic dicarboxylic acids include hexahydrophthalic acid. Examples of other carboxylic acids include dimer acids, hydrogenated dimer acids, and hetic acid. Examples of acid anhydrides include oxalic acid anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, alkyl succinic anhydride, tetrahydrophthalic anhydride, and trimellitic anhydride. Examples of acid halides include oxalic acid dichloride, adipic acid dichloride, and sebacate acid dichloride. These can be used individually or in combination of two or more. From the viewpoint of initial tack, saturated aliphatic dicarboxylic acids and aromatic dicarboxylic acids are preferred, and adipic acid and isophthalic acid are more preferred.

[0034] Furthermore, examples of polyester polyols include plant-derived polyester polyols. Specifically, plant-derived polyester polyols are obtained by condensing a hydroxycarboxylic acid of a hydroxyl group-containing vegetable oil fatty acid with a polyhydric alcohol as an initiator under known conditions.

[0035] Furthermore, lactone-based polyester polyols can be mentioned as examples of polyester polyols. Lactone-based polyester polyols can be obtained, for example, by ring-opening polymerization of lactones using a polyhydric alcohol as an initiator. Examples of lactones include ε-caprolactone and γ-valerolactone. More specifically, polycaprolactone polyols and polyvalerolactone polyols can be mentioned as examples of lactone-based polyester polyols. In addition, alcohol-modified lactone-based polyester polyols can be obtained by copolymerizing a lactone-based polyester polyol with the dihydric alcohols mentioned above.

[0036] These polyester polyols can be used individually or in combination of two or more types. Preferably, the polyester polyols are polycondensates of polyhydric alcohols and polybasic acids.

[0037] The number-average molecular weight of the polyester polyol is, for example, 400 or more, preferably 500 or more. Alternatively, the number-average molecular weight of the polyester polyol is, for example, 20,000 or less, preferably 10,000 or less, more preferably 5,000 or less, even more preferably 2,000 or less, even more preferably 1,000 or less, and particularly preferably 800 or less. If the number-average molecular weight of the polyester polyol is within the above range, an adhesive with excellent gas barrier properties, adhesion, and initial tack can be obtained.

[0038] The average number of hydroxyl groups in polyester polyols is, for example, 1.8 or more, preferably 2 or more. Alternatively, the average number of hydroxyl groups in polyester polyols is, for example, 4 or less, preferably 3 or less, and more preferably 2.5 or less.

[0039] Macropolyols may optionally contain other macropolyols as components. These other macropolyols are macropolyols other than polyester polyols.

[0040] Other macropolyols include, for example, polyether polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. These can be used individually or in combination of two or more types.

[0041] The content of other macropolyols relative to the total amount of macropolyols is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass. Furthermore, the content of polyester polyols relative to the total amount of macropolyols is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. In other words, the macropolyols are particularly preferably polyester polyols.

[0042] The number-average molecular weight of the macropolyol is, for example, 400 or more, preferably 500 or more, from the viewpoint of gas barrier properties and initial tack. Alternatively, the number-average molecular weight of the macropolyol is, for example, 20,000 or less, preferably 10,000 or less, more preferably 5,000 or less, even more preferably 2,000 or less, even more preferably 1,000 or less, and particularly preferably 800 or less.

[0043] The average number of hydroxyl groups in a macropolyol is, for example, 1.8 or more, preferably 2 or more. Alternatively, the average number of hydroxyl groups in a macropolyol is, for example, 4 or less, preferably 3 or less, and more preferably 2.5 or less.

[0044] Low molecular weight polyols are organic compounds that have two or more hydroxyl groups in their molecule and have a relatively low molecular weight. "Relatively low molecular weight" means a molecular weight of less than 400. That is, the molecular weight of a low molecular weight polyol is less than 400, preferably 300 or less, and more preferably 150 or less. Furthermore, the molecular weight of a low molecular weight polyol is usually 40 or more.

[0045] In order to obtain excellent gas barrier properties and adhesive strength by incorporating a specific skeleton (structural formula (A)) described later into the isocyanate group-terminated prepolymer, the low molecular weight polyol contains a low molecular weight diol as an essential component. That is, the polyol component as a raw material for the isocyanate group-terminated prepolymer contains a low molecular weight diol as a low molecular weight polyol.

[0046] Low molecular weight polyols are preferably composed of low molecular weight diols. Examples of low molecular weight diols include dihydric alcohols. Examples of dihydric alcohols include ethylene glycol, propylene glycol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, diethylene glycol, triethylene glycol, and dipropylene glycol. In addition, polymers obtained by addition polymerization of alkylene oxide to a dihydric alcohol so that the number average molecular weight is 400 or less can also be used as dihydric alcohols.

[0047] These low molecular weight diols can be used alone or in combination of two or more. The low molecular weight diols preferably consist of ethylene glycol, propylene glycol, diethylene glycol and / or dipropylene glycol, more preferably consist of ethylene glycol, diethylene glycol and / or propylene glycol, even more preferably consist of ethylene glycol, diethylene glycol and / or propylene glycol, and particularly preferably consist of ethylene glycol and diethylene glycol.

[0048] Low molecular weight polyols may optionally contain low molecular weight polyols of trivalent or higher. Examples of low molecular weight polyols of trivalent or higher include trihydric alcohols and alcohols of tetravalent or higher. Examples of trihydric alcohols include glycerin and trimethylolpropane. Also, as trihydric alcohols, polymers obtained by addition polymerization of alkylene oxide to a trihydric alcohol so that the number average molecular weight is 400 or less are also included. Examples of alcohols of tetravalent or higher include diglycerin, pentaerythritol, and dipentaerythritol. These can be used individually or in combination of two or more.

[0049] The content of low molecular weight polyols with a valency of 3 or higher relative to the total amount of low molecular weight polyols is, for example, 50% by mass or less, preferably 30% by mass or less, more preferably 10% by mass or less, and particularly preferably 0% by mass. Furthermore, the content of low molecular weight diols relative to the total amount of low molecular weight polyols is, for example, 50% by mass or more, preferably 70% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. In other words, the low molecular weight polyols are particularly preferably composed of low molecular weight diols.

[0050] In the polyol component, the content ratio of macropolyols and the content ratio of low molecular weight polyols are appropriately set so that the ratio of the specific skeleton (structural formula (A)) described later in the isocyanate group-terminated prepolymer falls within a predetermined range.

[0051] For example, the macropolyol is, for example, 50% by mass or more, preferably 60% by mass or more, relative to the total amount of polyol components. Also, the macropolyol is, for example, 90% by mass or less, preferably 80% by mass or less. Also, the low molecular weight polyol is, for example, 10% by mass or more, preferably 20% by mass or more. Also, the low molecular weight polyol is, for example, 50% by mass or less, preferably 40% by mass or less.

[0052] Isocyanate-terminated prepolymers are obtained by urethane-forming a polyisocyanate component and a polyol component in a predetermined equivalent ratio.

[0053] More specifically, the equivalent ratio (NCO / OH) of isocyanate groups in the polyisocyanate component to hydroxyl groups in the polyol component is greater than 1, for example, 1.1 or more, preferably 1.5 or more, more preferably 2.0 or more, for example, 15.0 or less, preferably 10.0 or less, more preferably 8.0 or less.

[0054] In the urethane formation reaction, the reaction temperature is, for example, 20°C or higher, preferably 50°C or higher, and for example, 150°C or lower, preferably 120°C or lower. The reaction time is 0.5 hours or more, preferably 1 hour or more, and for example, 18 hours or less, preferably 10 hours or less.

[0055] Furthermore, organic solvents may be added to the urethane reaction as needed. Examples of organic solvents include ketones, nitriles, alkyl esters, aliphatic hydrocarbons, alicyclic hydrocarbons, aromatic hydrocarbons, ethers, glycol ether esters, halogenated aliphatic hydrocarbons, and polar aprotons. These can be used individually or in combination of two or more. The amount of organic solvent added should be appropriately determined according to the purpose and application.

[0056] Furthermore, a urethane catalyst may be added to the polymerization reaction described above, if necessary. Examples of urethane catalysts include amines, organometallic compounds, and potassium salts. These can be used individually or in combination of two or more types. The amount of urethane catalyst added should be set appropriately depending on the purpose and application.

[0057] The above components are then reacted until the isocyanate group content reaches a predetermined value. This yields an isocyanate group-terminated prepolymer.

[0058] The isocyanate group content of the isocyanate-terminated prepolymer is, for example, 5.0% by mass or more, more preferably 10.0% by mass or more, more preferably 15.0% by mass or more, for example 30.0% by mass or less, and preferably 25.0% by mass or less. The isocyanate group content can be determined by titration with di-n-butylamine and FT-IR analysis.

[0059] Furthermore, after the reaction described above, any unreacted polyisocyanate components can be removed by known removal methods. Examples of removal methods include distillation and extraction.

[0060] Furthermore, isocyanate-terminated prepolymers can be prepared as solutions of the organic solvents described above. In this case, the solid content concentration of the solution is set appropriately according to the purpose and application. The organic solvent may also be removed by the removal method described above, if necessary.

[0061] In the above method, if the polyisocyanate component, which is a raw material for the isocyanate-terminated prepolymer, contains xylylene diisocyanate, and the polyol component, which is a raw material for the isocyanate-terminated prepolymer, contains a dihydric alcohol, then the isocyanate-terminated prepolymer contains a urethane skeleton formed by xylylene diisocyanate and a dihydric alcohol. More specifically, the isocyanate-terminated prepolymer contains a skeleton shown in the following structural formula (A).

[0062] [ka] (In the formula, X represents a low molecular weight diol residue.)

[0063] In structural formula (A), X represents a low molecular weight diol residue. More specifically, X includes a low molecular weight diol residue contained in a low molecular weight polyol used as a raw material for the isocyanate-terminated prepolymer. Preferably, the above isocyanate-terminated prepolymer contains the skeleton shown in structural formula (A) in a predetermined amount or more.

[0064] More specifically, the content of the skeleton represented by structural formula (A) relative to the total amount of isocyanate group-terminated prepolymer is 40% by mass or more, preferably 45% by mass or more, and more preferably 50% by mass or more, from the viewpoint of gas barrier properties. Furthermore, the content of the skeleton represented by structural formula (A) relative to the total amount of isocyanate group-terminated prepolymer is, for example, 80% by mass or less, preferably 70% by mass or less, from the viewpoint of initial tack and adhesion.

[0065] The proportion of the skeleton shown in structural formula (A) can be calculated based on the amount and yield of the raw materials for the isocyanate group-terminated prepolymer described above.

[0066] In an isocyanate group-terminated prepolymer, if the content of the skeleton shown in the above structural formula (A) is above a predetermined amount, an adhesive is obtained that exhibits excellent gas barrier properties and adhesion, as well as excellent initial tack.

[0067] More specifically, adhesives include moisture-curing adhesives (hereinafter referred to as moisture-curing adhesives) and two-component curing adhesives (hereinafter referred to as two-component curing adhesives).

[0068] If the adhesive is a moisture-curing adhesive (one-component curing adhesive), it consists of only one component (one liquid) containing an isocyanate group-terminated prepolymer.

[0069] More specifically, the moisture-curing adhesive contains, as an essential component, an isocyanate-terminated prepolymer having the skeleton shown in the above structural formula (A).

[0070] Furthermore, moisture-curing adhesives may contain additives as optional components. Examples of additives include phosphoric acid, phosphoric acid derivatives, silane coupling agents, defoaming agents, epoxy resins, catalysts, coating properties improvers, leveling agents, antioxidants, UV absorbers, plasticizers, surfactants, pigments, fillers, organic microparticles, inorganic microparticles, and antifungal agents. The proportion of additives is determined appropriately depending on the purpose and application.

[0071] Furthermore, moisture-curing adhesives may contain the above-mentioned organic solvents as optional components. In other words, moisture-curing adhesives may also be solvent-based adhesives. The proportion of organic solvents used should be appropriately determined according to the purpose and application. Also, moisture-curing adhesives do not necessarily have to contain organic solvents. In other words, moisture-curing adhesives may also be solvent-free adhesives.

[0072] Moisture-curing adhesives cure in response to moisture, for example. That is, the isocyanate groups at the molecular ends of the isocyanate-terminated prepolymer react with moisture and cure. Moisture includes, for example, water in the atmosphere and amine vapors.

[0073] Such moisture-curing adhesives contain an isocyanate group-terminated prepolymer having the skeleton shown in the above structural formula (A). Therefore, the cured product of a moisture-curing adhesive cured by moisture contains the skeleton shown in the above structural formula (A).

[0074] The content of the skeleton represented by structural formula (A) relative to the total amount of cured product of the moisture-curing adhesive is, for example, 40% by mass or more, preferably 45% by mass or more, and more preferably 50% by mass or more, from the viewpoint of gas barrier properties. Furthermore, the content of the skeleton represented by structural formula (A) relative to the total amount of cured product of the moisture-curing adhesive is, for example, 80% by mass or less, preferably 70% by mass or less, from the viewpoint of initial tack and adhesion.

[0075] The proportion of the skeleton shown in structural formula (A) can be calculated based on the preparation and yield of the raw materials for the moisture-curing adhesive described above.

[0076] In such a moisture-curing adhesive, the isocyanate-terminated prepolymer contains a reaction product of a polyisocyanate component containing xylylene diisocyanate and a polyol component containing a polyester polyol and a low molecular weight diol, and the isocyanate-terminated prepolymer contains the skeleton shown in the above structural formula (A) in a predetermined amount or more. Therefore, the moisture-curing adhesive has excellent initial tack, gas barrier properties, and adhesion. In particular, the above moisture-curing adhesive can exhibit excellent gas barrier properties by adhering to an inorganic thin film described later.

[0077] Furthermore, if the adhesive is a two-component curing adhesive, it is a resin kit containing the first and second components separately. The first and second components are prepared as a set and mixed together at the time of use.

[0078] In a two-component curing adhesive, the first liquid contains the above-mentioned isocyanate-terminated prepolymer as an essential component. The content of the above-mentioned isocyanate-terminated prepolymer is, for example, 80% by mass or more, preferably 90% by mass or more, relative to the total amount of the first liquid. The first liquid may also contain additives and organic solvents as needed. In other words, the first liquid preferably consists of the above-mentioned isocyanate-terminated prepolymer, additives as needed, and organic solvents as needed.

[0079] In a two-component curing adhesive, the second component includes, for example, the low molecular weight polyol described above, and preferably the low molecular weight diol described above.

[0080] In the second liquid, the low molecular weight diol preferably comprises ethylene glycol, propylene glycol and / or dipropylene glycol, more preferably comprises ethylene glycol and / or propylene glycol, even more preferably comprises ethylene glycol and / or propylene glycol, and particularly preferably comprises ethylene glycol.

[0081] The low molecular weight diol contained in the second solution may be of a different type from, or the same as, the low molecular weight diol contained in the isocyanate group-terminated prepolymer. That is, the low molecular weight diol contained in the second solution and the low molecular weight diol used as a raw material for the isocyanate group-terminated prepolymer may contain the same type of dihydric alcohol, or they may contain different types of dihydric alcohols. Preferably, the low molecular weight diol contained in the second solution and the low molecular weight diol used as a raw material for the isocyanate group-terminated prepolymer contain the same type of dihydric alcohol, and more preferably, they consist of the same type of dihydric alcohol.

[0082] The second liquid may further contain the above-mentioned low molecular weight polyols of trivalentity or higher. Preferably, the second liquid does not contain the above-mentioned low molecular weight polyols of trivalentity or higher. The second liquid may also further contain the above-mentioned macropolyols. Examples of macropolyols include polyester polyols, polyether polyols, polycarbonate polyols, polyurethane polyols, epoxy polyols, vegetable oil polyols, polyolefin polyols, acrylic polyols, and vinyl monomer-modified polyols. Preferably, the second liquid does not contain macropolyols.

[0083] Furthermore, the second liquid may contain additives and organic solvents as needed. In other words, the second liquid preferably consists of the low molecular weight diol mentioned above, additives as needed, and organic solvents as needed.

[0084] Furthermore, the two-component curing adhesive may contain the above-mentioned additives as optional components. The additives may be added to the first component, to the second component, or to both the first and second components. The mixing ratio of the additives is determined appropriately depending on the purpose and application.

[0085] Furthermore, the two-component curing adhesive may contain the above-mentioned organic solvent as an optional component. The organic solvent may be contained in the first liquid, in the second liquid, or in both the first and second liquids. Also, when mixing the first liquid, which does not contain an organic solvent, with the second liquid, which does not contain an organic solvent, the first liquid and / or the second liquid can be dissolved in the organic solvent. In other words, the two-component curing adhesive may be a solvent-based adhesive. The blending ratio of the organic solvent is set appropriately according to the purpose and application. Also, the two-component curing adhesive does not have to contain an organic solvent. In other words, the two-component curing adhesive may be a solvent-free adhesive.

[0086] Two-component curing adhesives harden when the first and second components are mixed, as the isocyanate groups at the molecular ends of the isocyanate-terminated prepolymer in the first component react with the hydroxyl groups of the low molecular weight polyol in the second component.

[0087] When using a two-component curing adhesive, the mixing ratio of the first and second liquids is appropriately set according to the purpose and application. For example, the equivalent ratio R(NCO / OH) of the isocyanate groups of the isocyanate-terminated prepolymer in the first liquid to the hydroxyl groups of the low molecular weight polyol in the second liquid is, for example, 0.5 or more, preferably 0.8 or more. Also, the equivalent ratio R(NCO / OH) of the isocyanate groups of the isocyanate-terminated prepolymer in the first liquid to the hydroxyl groups of the low molecular weight polyol in the second liquid is, for example, 5 or less, preferably 2 or less, more preferably 1.5 or less, and even more preferably 1.2 or less.

[0088] Such a two-component curing adhesive contains the above-mentioned isocyanate group-terminated prepolymer in the first component. Therefore, the cured product obtained by curing the two-component curing adhesive by mixing the first and second components contains the skeleton shown in structural formula (A). Furthermore, if the second component contains a low molecular weight diol, the skeleton shown in structural formula (A) is formed by the reaction of the first and second components. Therefore, the cured product obtained by curing the two-component curing adhesive can contain, as the skeleton shown in structural formula (A), the skeleton contained in the above-mentioned isocyanate group-terminated prepolymer, as well as the skeleton formed by the reaction of the first and second components.

[0089] The content of the skeleton represented by structural formula (A) relative to the total amount of cured product of the two-component curing adhesive is, for example, 50% by mass or more, preferably 55% by mass or more, and more preferably 60% by mass or more, from the viewpoint of gas barrier properties. Furthermore, the content of the skeleton represented by structural formula (A) relative to the total amount of cured product of the two-component curing adhesive is, for example, 80% by mass or less, preferably 70% by mass or less, from the viewpoint of initial tack and adhesion.

[0090] The proportion of the skeleton shown by structural formula (A) can be calculated based on the amount and yield of the raw materials for the two-component curing adhesive described above, and the mixing ratio of the first and second components.

[0091] In such a two-component curing adhesive, the isocyanate-terminated prepolymer contains a reaction product of a polyisocyanate component containing xylylene diisocyanate and a polyol component containing a polyester polyol and a low molecular weight diol, and the isocyanate-terminated prepolymer contains the skeleton shown in the above structural formula (A) in a predetermined amount or more. Therefore, the two-component curing adhesive has excellent initial tack, gas barrier properties, and adhesion. In particular, the above two-component curing adhesive can exhibit excellent gas barrier properties by adhering to an inorganic thin film described later.

[0092] Furthermore, if the content ratio of the skeleton represented by structural formula (A) relative to the total amount of cured product of the two-component curing adhesive is within the above range, the content ratio of the skeleton represented by structural formula (A) of the isocyanate group-terminated prepolymer in the first liquid may be less than 40% by mass.

[0093] Such adhesives also contain the skeleton represented by the above structural formula (A) in a predetermined or greater proportion relative to the total amount of cured product of the two-component curing adhesive. Therefore, the adhesive of the present invention exhibits excellent gas barrier properties and adhesion.

[0094] The above-mentioned adhesives (moisture-curing adhesives and two-component curing adhesives) are suitably used in the manufacture of laminates.

[0095] In Figure 1, the laminate film 1 as a laminate comprises a base material 2, an adhesive layer 3 placed on the base material 2, an inorganic thin film 4 placed on the adhesive layer 3, and a film 5 placed on the inorganic thin film 4.

[0096] Examples of the base material 2 include a resin film and a paper base material having a resin layer. In the resin film, examples of the resin include olefin polymers, polyester polymers, polyamide polymers, and vinyl polymers. Examples of olefin polymers include polyethylene and polypropylene. Examples of polyester polymers include polyalkylene terephthalate and polyalkylene naphthalate. Examples of polyamide polymers include nylon 6 and nylon 66. Examples of vinyl polymers include polyvinyl chloride, ethylene-vinyl acetate copolymer and ethylene-vinyl alcohol copolymer. A paper base material having a resin layer comprises, for example, a paper base material and a resin layer formed on at least one side of the paper base material. The resin layer is formed, for example, by a coating resin. Examples of coating resins include styrene-butadiene copolymer, acrylic polymer and styrene-acrylic copolymer. These can be used alone or in combination of two or more. Preferably, a resin film is used.

[0097] The resin film may be surface-treated as needed. Examples of surface treatments include corona discharge treatment and primer treatment.

[0098] Furthermore, the resin film may be an unstretched film or a stretched film. Examples of stretched films include uniaxially oriented films and biaxially oriented films. The resin film may also be a single-layer film or a multi-layer film.

[0099] The thickness of the base material 2 is not particularly limited, but for example, it is 5 μm or more, preferably 10 μm or more. Alternatively, the thickness of the base material 2 may be 200 μm or less, preferably 100 μm or less.

[0100] The adhesive layer 3 is the cured product of the adhesive described above. The adhesive layer 3 is placed between the substrate 2 and the inorganic thin film 4, and adheres the substrate 2 and the inorganic thin film 4 together. Furthermore, the adhesive layer 3 exhibits gas barrier properties by adhering closely to the inorganic thin film 4. If the substrate 2 is a paper substrate having a resin layer, the adhesive layer 3 is placed on top of the resin layer.

[0101] As will be described in more detail later, such an adhesive layer 3 is obtained by applying the above-mentioned adhesive (moisture-curing adhesive and / or two-component curing adhesive) to the substrate 2, laminating an inorganic thin film 4 (composite film 6) onto the coating, and then curing the adhesive.

[0102] The thickness of the adhesive layer 3 is not particularly limited, but is, for example, 5 μm or more, preferably 10 μm or more. Alternatively, the thickness of the adhesive layer 3 may be 200 μm or less, preferably 100 μm or less.

[0103] The inorganic thin film 4 is a thin film of an inorganic material. Examples of inorganic materials include metals and metal oxides. Examples of metals include magnesium, calcium, barium, titanium, zirconium, aluminum, indium, silicon, germanium, and tin. Examples of metal oxides include magnesium oxide, titanium oxide, aluminum oxide, indium oxide, silicon oxide, tin oxide, and silicon oxide nitride. These can be used individually or in combination of two or more. From the viewpoint of gas barrier properties and production efficiency, aluminum, silicon, and their oxides are preferred.

[0104] The thickness of the inorganic thin film 4 is not particularly limited, but is, for example, 1 nm or more, preferably 2 nm or more. Alternatively, the thickness of the inorganic thin film 4 may be 500 nm or less, preferably 300 nm or less.

[0105] Film 5 is a plastic film prepared separately from the base material 2. Examples of film 5 include the resin film described above as the base material 2.

[0106] The thickness of film 5 is not particularly limited, but for example, it is 5 μm or more, preferably 10 μm or more. Alternatively, the thickness of film 5 may be 200 μm or less, preferably 100 μm or less.

[0107] The inorganic thin film 4 and the film 5 are preferably formed as a composite film 6. That is, the inorganic thin film 4 is preferably formed on the film 5. This gives a composite film 6 comprising the inorganic thin film 4 and the film 5. Examples of methods for forming the inorganic thin film 4 include vapor deposition (vacuum deposition, EB deposition, etc.), sputtering, ion plating, lamination, and plasma vapor deposition (CVD). From the viewpoint of manufacturing efficiency, vacuum deposition is preferred.

[0108] To obtain such a laminate film 1, for example, first prepare a substrate 2 and a composite film 6. Then, in this method, apply the adhesive to one side of the substrate 2 in the thickness direction. Examples of application methods include the bar coating method, curtain coating method, roll coating method, and blade coating method. The application temperature for solvent-based adhesives is, for example, room temperature. The application temperature for solvent-free adhesives is, for example, 35°C or higher, preferably 40°C or higher. The application temperature for solvent-free adhesives is, for example, 100°C or lower, preferably 90°C or lower. The application amount for both solvent-based and solvent-free adhesives is, for example, 0.5 g / m² in terms of solid content. 2 Preferably, 1.0 g / m 2 Above all, more comfortably, 1.5g / m 2 That's all. Also, the application amount is, for example, 5g / m². 2 The following applies:

[0109] Next, the composite film 6 is laminated onto the adhesive coating. More specifically, the inorganic thin film 4 of the composite film 6 is brought into close contact with the adhesive coating. If the adhesive contains an organic solvent, the organic solvent in the adhesive is evaporated at room temperature or under heating.

[0110] Subsequently, the adhesive coating is cured at room temperature or under heating. The curing temperature is, for example, 20°C or higher, preferably 30°C or higher. Alternatively, the curing temperature is, for example, 100°C or lower, preferably 80°C or lower. The curing time is, for example, 1 hour or more, preferably 5 hours or more. Alternatively, the curing time is, for example, 7 days or less, preferably 5 days or less.

[0111] As a result, an adhesive layer 3, consisting of a cured adhesive, is formed between the substrate 2 and the inorganic thin film 4. This results in a laminate film 1.

[0112] Such a laminate film 1 comprises an adhesive layer 3, which is a cured product of the adhesive described above. Furthermore, an inorganic thin film 4 is placed on top of the adhesive layer 3. Therefore, the laminate film 1 has excellent initial tack, gas barrier properties, and adhesion of the adhesive layer 3.

[0113] In the above description, the laminate film 1 includes film 5, but the laminate film 1 does not necessarily have to include film 5. In such cases, the inorganic thin film 4 is formed as a single thin film and laminated onto the adhesive coating. [Examples]

[0114] Next, the present invention will be described based on examples and comparative examples, but the present invention is not limited to the following examples. Unless otherwise specified, "parts" and "%" are based on mass. Furthermore, specific numerical values ​​such as blending ratios (content), physical properties, and parameters used in the following description may be replaced with the corresponding upper limits (numerical values ​​defined as "less than or equal to" or "less than") or lower limits (numerical values ​​defined as "greater than or equal to" or "greater than") of the blending ratios (content), physical properties, and parameters described in the "Modes for Carrying Out the Invention" above.

[0115] 1. Macropolyols Preparation Examples 1-3 (Polyester Polyol A-C) A polybasic acid and a polyhydric alcohol were mixed according to the formulations shown in Table 1. The mixture was esterified under a nitrogen atmosphere at 160-220°C. A predetermined amount of condensation water was then removed by distillation. This yielded polyester polyols. The number-average molecular weight (in polystyrene equivalent) of each polyester polyol was measured by gel permeation chromatography. The results are shown in Table 1.

[0116] Preparation Example 4 (Polyether Polyol D) As polyether polyol D, commercially available polytetramethylene ether glycol (trade name PTMEG-650, manufactured by Korea PTG, number average molecular weight 650) was prepared.

[0117] 2. Isocyanate-terminated prepolymers Synthesis Examples 1-8 and Comparative Synthesis Examples 1-3 Polyisocyanate components were mixed with low molecular weight polyols and macropolyols according to the formulations described in Tables 2 and 3. These mixtures were subjected to a urethane reaction at 80°C under a nitrogen atmosphere. Next, it was confirmed that the amine equivalent of the reaction solution reached a predetermined value (see Table (Before Distillation)). The reaction solution was then subjected to thin-film distillation to remove unreacted polyisocyanate components. This yielded isocyanate-terminated prepolymers. Tables 2 and 3 show the mass percentage (wt) of each raw material and the amine equivalent of the isocyanate-terminated prepolymer (after distillation).

[0118] The content of the skeleton represented by structural formula (A) in each isocyanate-terminated prepolymer (content of structural formula (A)) was calculated based on the amount charged and the yield. The results are shown in Tables 2 and 3.

[0119] 3.2-part curing adhesive Examples 1-12 and Comparative Examples 1-3 In the formulations described in Tables 4 to 6, an isocyanate-terminated prepolymer was prepared as the first liquid. A low molecular weight polyol was prepared as the second liquid. This prepared a two-component curing adhesive. The equivalent ratio (NCO / OH) of isocyanate groups in the first liquid to hydroxyl groups in the second liquid was set to approximately 1.5.

[0120] In Example 1, the first solution contained acetone as the organic solvent. In Examples 6, 8, 9-11 and Comparative Examples 1-3, the first solution contained ethyl acetate as the organic solvent. In other words, solvent-based adhesives were prepared as two-component curing adhesives.

[0121] Furthermore, in Examples 2-5, 7, and 12, the first and second liquids did not contain organic solvents. In other words, a solvent-free adhesive was prepared as a two-component curing adhesive.

[0122] Comparative Examples 4-5 In the formulation described in Table 7, an ethyl acetate solution (75% solids by mass) of the trimethylolpropane adduct of xylylene diisocyanate (XDI-TMP) was prepared as the first solution. A low molecular weight polyol was prepared as the second solution. Furthermore, in Comparative Example 7, ethanol was mixed with the second solution. This prepared a two-component curing adhesive.

[0123] 4. Laminate (two-component curing adhesive) As the first substrate, a corona-treated biaxially oriented polypropylene film (product name Pyrene® Film OT P-2161, thickness 20 μm, manufactured by Toyobo, hereinafter referred to as OPP film) was prepared.

[0124] In addition, an unstretched polypropylene film treated with aluminum vapor deposition (product name MLCP WS, thickness 25 μm, manufactured by Mitsui Chemicals Tohcello, hereinafter referred to as VM-CPP film) was prepared as a second substrate.

[0125] Furthermore, the first and second components of a two-component curing adhesive were mixed. The two-component curing adhesive (mixture) was then applied to the corona-treated surface of the OPP film. In addition, a solvent-based adhesive was applied using a bar coater. A solvent-free adhesive was also applied using a solvent-free laminator. The application amount is 2.0 g / m² of solid content weight. 2 That was the case.

[0126] Subsequently, the adhesive-coated surface of the OPP film and the aluminum-deposited surface of the VM-CPP film were bonded together to obtain a laminate. Furthermore, the laminate was cured at 40°C for 3 days.

[0127] 5. Moisture-curing adhesive Examples 13-14 An isocyanate-terminated prepolymer was prepared as a moisture-curing adhesive using the formulations described in Table 8.

[0128] In Example 13, the isocyanate group-terminated prepolymer contained ethyl acetate as an organic solvent. In other words, a solvent-based adhesive was prepared as a moisture-curing adhesive.

[0129] Furthermore, in Example 14, the isocyanate group-terminated prepolymer did not contain an organic solvent. In other words, a solvent-free adhesive was prepared as a moisture-curing adhesive.

[0130] 6. Laminate (moisture-curing adhesive) A corona-treated OPP film was prepared as the first substrate. A VM-CPP film was prepared as the second substrate. A moisture-curing adhesive was then applied to the corona-treated surface of the OPP film. The application amount was 2.0 g / m² of solids weight. 2 That was the case.

[0131] Subsequently, the adhesive-coated surface of the OPP film and the aluminum-deposited surface of the VM-CPP film were bonded together to obtain a laminate. Furthermore, the laminate was cured at 40°C for 3 days.

[0132] 7. Evaluation (1) Oxygen permeability The oxygen permeability of the laminate was measured using an oxygen permeability meter (OX-TRAN2 / 20, MOCON). The measurement temperature was 20°C and the relative humidity was 80% (80%RH). The unit is cc / m 2 • 24 hours • 1 atm

[0133] (2) Initial tack (initial adhesive strength) Immediately after lamination of the OPP film and the VM-CPP film, the two films were peeled apart by hand. This allowed for evaluation of the tack (initial tack) of the adhesive-coated surface. The evaluation criteria are as follows. ○: There was clearly a tuck. △: There was a slight tuck. ×: There was no tuck.

[0134] (3) Adhesive strength The adhesive strength of the laminate was measured by a T-peel test in accordance with JIS K 6854 (1999).

[0135] [Table 1]

[0136] [Table 2]

[0137] [Table 3]

[0138] [Table 4]

[0139] [Table 5]

[0140] [Table 6]

[0141] [Table 7]

[0142] [Table 8]

[0143] The details of the abbreviations used in the table are as follows. XDI: Xylylene diisocyanate XDI-TMP: Ethyl acetate solution of the trimethylolpropane adduct of xylylene diisocyanate (75% solids by mass) EG: Ethylene glycol PG: Propylene glycol DEG: Diethylene glycol DPG: Dipropylene glycol MF: Substrate fracture (OPP film rupture, OPP film surface delamination, transfer of inorganic thin film of VM-CPP) [Explanation of symbols]

[0144] 1. Laminating film 2 Base material 3 Adhesive layer 4. Inorganic Thin Films 5 Film 6. Composite film

Claims

1. A method for producing an adhesive containing an isocyanate group-terminated prepolymer, The method for producing the isocyanate-terminated prepolymer is as follows: A step of obtaining a reaction solution by reacting a polyisocyanate component with a polyol component in a urethane reaction, The process includes distilling the reaction solution to obtain an isocyanate-terminated prepolymer. The aforementioned polyisocyanate component consists of xylylene diisocyanate. The aforementioned polyol component consists of a polyester polyol and a low molecular weight diol. The low molecular weight diol is present in an amount of 10% by mass or more and 40% by mass or less relative to the total amount of the polyol components. The amine equivalent of the reaction solution is 141 or more and 151 or less. A method for producing an adhesive, wherein the amine equivalent of the isocyanate group-terminated prepolymer is 328 or more and 403 or less.

2. The method for producing an adhesive according to claim 1, wherein the isocyanate group-terminated prepolymer includes a skeleton represented by structural formula (A). [Case 1] (In the formula, X represents a low molecular weight diol residue.)

3. The method for producing an adhesive according to claim 1, wherein the number average molecular weight of the polyester polyol is 500 or more and 1600 or less.

4. The method for manufacturing an adhesive according to claim 1, wherein the adhesive is a moisture-curing adhesive.

5. The adhesive is a two-component curing adhesive, A step of preparing a first liquid containing the isocyanate group-terminated prepolymer, A method for producing an adhesive according to claim 1, comprising the step of preparing a second liquid containing a low molecular weight polyol.

6. A method for manufacturing a laminate, The process of preparing the base material, The steps include: applying an adhesive obtained by the adhesive manufacturing method described in any one of claims 1 to 5 onto the substrate, and then arranging an adhesive layer obtained by curing the adhesive; A method for manufacturing a laminate, comprising the step of placing an inorganic thin film on the adhesive layer.

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