JP2014019711A - Laminating adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminating adhesive excellent in resistance to a high polar solvent, alkali resistance and adhesive strength between a film and an adhesive layer.SOLUTION: The laminating adhesive includes a polyisocyanate component and a polyol component. The polyol component includes a polyurethane polyol obtained by reacting an allophanate group containing polyisocyanate and a polymer of a diene monomer having a hydroxyl group at a molecular terminal.

Description

  The present invention relates to a laminating adhesive, and more particularly to a laminating adhesive used for laminating composite films.

  Conventionally, it is widely known that composite films obtained by bonding various films with an adhesive are used as packaging bags for storing various solutions.

  Examples of such an adhesive include a polyisocyanate component and a polyol component, and the polyisocyanate component contains an allophanate group-containing polyisocyanate obtained from a monool having 4 or more carbon atoms and a polyisocyanate. And / or the polyol component contains an allophanate group-containing polyurethane polyol obtained from an allophanate group-containing polyisocyanate and a polyol, and the polyol component and / or the polyol contains a naphthalene ring. Have been proposed (see, for example, Patent Document 1).

JP 2011-102387 A

  However, the adhesive for laminating described in Patent Document 1 does not have sufficient resistance to a high-polarity solvent and cannot maintain the adhesiveness for a long time at a high temperature when containing a high-polarity solvent. There is a case. Further, the adhesive composition described in Patent Document 1 does not have sufficient alkali resistance. For example, delamination may occur when a strong alkaline solution is accommodated.

  Accordingly, an object of the present invention is to provide an adhesive for laminating which has excellent resistance to high polar solvents and alkali resistance and has excellent adhesive strength between a film and an adhesive layer.

  In order to achieve the above object, the laminate adhesive of the present invention is a laminate adhesive containing a polyisocyanate component and a polyol component, and the polyol component contains an allophanate group-containing polyisocyanate and a hydroxyl group at the molecular end. It has a polyurethane polyol obtained by reacting with a polymer of a diene monomer.

  In the laminate adhesive of the present invention, it is preferable that the average number of functional groups of the polyisocyanate component exceeds 2.

  In the laminate adhesive of the present invention, it is preferable that the polymer has a number average molecular weight of 4000 or more.

  In the laminate adhesive of the present invention, it is preferable that the polymer is a polybutadiene polyol.

  In the laminate adhesive of the present invention, it is preferable that the polyol component contains a low molecular weight diol.

  In the laminate adhesive of the present invention, it is preferable that the polyisocyanate component contains a modified aromatic diisocyanate.

  The composite film obtained by bonding each film using the laminating adhesive of the present invention is excellent in resistance to highly polar solvents. Adhesive strength can be maintained.

  Moreover, since the composite film obtained by adhere | attaching between each film using the adhesive agent for lamination of this invention is excellent also in alkali resistance, it can be used also when accommodating a strong alkaline solution.

  Furthermore, the adhesive for lamination of the present invention has excellent adhesive strength between the film and the adhesive layer.

  Therefore, according to the laminating adhesive of the present invention, a packaging bag having excellent reliability can be obtained.

  The laminating adhesive of the present invention contains a polyisocyanate component and a polyol component.

  As a polyisocyanate component, a polyisocyanate monomer, a polyisocyanate modified body, etc. are mentioned, for example.

  Examples of the polyisocyanate monomer include polyisocyanates such as aromatic polyisocyanate, araliphatic polyisocyanate, and aliphatic polyisocyanate.

  Examples of the aromatic polyisocyanate include tolylene diisocyanate (2,4- or 2,6-tolylene diisocyanate or a mixture thereof) (TDI), phenylene diisocyanate (m-, p-phenylene diisocyanate or a mixture thereof), 4, 4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), diphenylmethane diisocyanate (4,4'-, 2,4'- or 2,2'-diphenylmethane diisocyanate or mixtures thereof) (MDI), Examples include aromatic diisocyanates such as 4,4′-toluidine diisocyanate (TODI) and 4,4′-diphenyl ether diisocyanate.

  Examples of the araliphatic polyisocyanate include xylylene diisocyanate (1,3- or 1,4-xylylene diisocyanate or a mixture thereof) (XDI), tetramethylxylylene diisocyanate (1,3- or 1,4-tetra). Methyl xylylene diisocyanate or a mixture thereof (TMXDI), aromatic aliphatic diisocyanates such as ω, ω′-diisocyanate-1,4-diethylbenzene, and the like.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, 1,2-propylene diisocyanate, butylene diisocyanate (tetramethylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate), 1 , 5-pentamethylene diisocyanate (PDI), 1,6-hexamethylene diisocyanate (HDI), 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl capate Group diisocyanate and the like.

Aliphatic polyisocyanates include alicyclic polyisocyanates. Examples of the alicyclic polyisocyanate include 1,3-cyclopentane diisocyanate, 1,3-cyclopentene diisocyanate, cyclohexane diisocyanate (1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate), and 3-isocyanatomethyl-3. , 5,5-trimethylcyclohexylisocyanate (isophorodiisocyanate) (IPDI), methylenebis (cyclohexylisocyanate) (4,4'-, 2,4'- or 2,2'-methylenebis (cyclohexylisocyanate, these Trans, Trans - body, Trans, Cis body, Cis, Cis body, or mixtures _thereof)) (H 12 _MDI), methylcyclohexane diisocyanate (methyl-2,4-cyclohexane Isocyanate, methyl-2,6-cyclohexane diisocyanate), norbornane diisocyanate (various isomers or mixtures thereof) (NBDI), bis (isocyanatomethyl) cyclohexane (1,3- or 1,4-bis (isocyanatomethyl) cyclohexane Or a mixture thereof) (H ₆ XDI) and the like.

  These polyisocyanate monomers can be used alone or in combination of two or more.

  Examples of the polyisocyanate-modified product include, for example, multimers, biuret-modified products, allophanate-modified products, oxadiazinetrione-modified products, polyol-modified products (alcohol-added (adduct) products), and the like. It is done.

  Examples of the multimer include dimer (uretdione group-containing polyisocyanate, dimer-modified product), trimer (isocyanurate group-containing polyisocyanate, trimer-modified product), pentamer, heptamer, or a mixture thereof. Is mentioned. The polyisocyanate monomer multimer is preferably a trimer of polyisocyanate monomer.

  The trimer can be obtained by reacting the above-described polyisocyanate monomer in the presence of a known isocyanurate-forming catalyst and trimerization.

  The biuret modified product is obtained by reacting the above-described polyisocyanate monomer with, for example, water, a tertiary alcohol (for example, t-butyl alcohol), a secondary amine (for example, dimethylamine, diethylamine) or the like. Then, it can be obtained by further reacting in the presence of a known biuretization catalyst.

  The allophanate-modified product will be described in detail later, but after the urethanation reaction of the above-described polyisocyanate monomer and monool (described later) in the presence of a known urethanization catalyst, further, the known allophanate formation. It can be obtained by carrying out an allophanatization reaction in the presence of a catalyst.

  The modified oxadiazine trione can be obtained by reacting a polyisocyanate monomer with carbon dioxide.

  The polyol-modified product can be obtained by a reaction between the polyisocyanate monomer described above and a low molecular weight polyol (described later).

  Of the polyisocyanate-modified products, a polyol-modified product is preferable.

  These polyisocyanate-modified products can be used alone or in combination of two or more.

  The polyisocyanate component is preferably a polyisocyanate-modified product, more preferably a modified product of aromatic diisocyanate, a modified product of araliphatic diisocyanate, and more preferably a modified product of aromatic diisocyanate.

  By using a modified aromatic diisocyanate as the polyisocyanate component, it is possible to ensure excellent resistance to high polar solvents and alkali resistance.

  Moreover, as a polyisocyanate component, the above-mentioned polyisocyanate monomer and polyisocyanate modified body can also be used together, for example. In the case where the polyisocyanate monomer and the polyisocyanate-modified product are used in combination, the blending ratio thereof is appropriately set according to the purpose and application.

  The average number of functional groups of the polyisocyanate component is, for example, 2 or more, preferably more than 2, more preferably 3 or more, and for example, 10 or less, preferably 5 or less.

  If the average number of functional groups of the polyisocyanate component exceeds 2, the resistance to highly polar solvents and the alkali resistance can be further improved.

  The isocyanate group content (NCO%) of the polyisocyanate component is, for example, 1 or more, preferably 5 or more, for example, 50 or less, preferably 30 or less.

  The isocyanate group content can be determined by an isocyanate group content test described in JIS K7301 (the same applies hereinafter).

  The polyisocyanate component can be diluted with an organic solvent (described later).

  Examples of the organic solvent include ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, nitriles such as acetonitrile, and alkyl esters such as methyl acetate, ethyl acetate, butyl acetate and isobutyl acetate, for example, Aliphatic hydrocarbons such as n-hexane, n-heptane and octane, for example, alicyclic hydrocarbons such as cyclohexane and methylcyclohexane, for example, aromatic hydrocarbons such as toluene, xylene and ethylbenzene, such as methyl Cellosolve acetate, ethyl cellosolve acetate, methyl carbitol acetate, ethyl carbitol acetate, ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3 Glycol ether esters such as methoxybutyl acetate and ethyl-3-ethoxypropionate, for example, ethers such as diethyl ether, tetrahydrofuran and dioxane, such as methyl chloride, methylene chloride, chloroform, carbon tetrachloride, methyl bromide, Halogenated aliphatic hydrocarbons such as methylene iodide and dichloroethane, for example, polar aprotics such as N-methylpyrrolidone, dimethylformamide, N, N′-dimethylacetamide, dimethyl sulfoxide, hexamethylphosphonamide, etc. It is done.

  These organic solvents can be used alone or in combination of two or more.

  When the polyisocyanate component is diluted with an organic solvent, the solid content concentration of the polyisocyanate component is, for example, 10% by mass or more, preferably 30% by mass or more, for example, 95% by mass or less, preferably 90%. It is below mass%.

  In addition, a polyisocyanate component can also be used without diluting with an organic solvent, ie, solid content concentration of 100 mass%.

  In the present invention, the polyol component contains a polyurethane polyol obtained by reacting an allophanate group-containing polyisocyanate with a polymer of a diene monomer having a hydroxyl group at the molecular terminal (hereinafter referred to as polydiene polyol). ing.

  The allophanate group-containing polyisocyanate is an allophanate-modified product of the above-described polyisocyanate monomer, and can be obtained, for example, by reacting the above-mentioned polyisocyanate monomer with monool and making it allophanate.

  Examples of the polyisocyanate monomer include the above-described polyisocyanate monomers, and preferably include aliphatic polyisocyanates.

  Monools include, for example, butanol, pentanol, hexanol, heptanol, octanol, nonanol, decanol, undecyl alcohol, dodecyl alcohol (lauryl alcohol), tridecyl alcohol, tetradecyl alcohol (myristyl alcohol), pentadecyl alcohol, hexadecyl alcohol Decyl alcohol (cetyl alcohol), heptadecyl alcohol, octadecyl alcohol (stearyl alcohol, octadecanol), nonadecyl alcohol, and isomers thereof (including 2-methyl-1-propanol (iso-butanol)), and , Other alkanols (C20-50 alcohol), and alkenyl alcohols such as oleyl alcohol, for example alkadiene such as octadienol Nord, for example, aliphatic monool such as polyethylene butylene mono-ol. Examples of monools include alicyclic monools such as cyclohexanol and methylcyclohexanol, and aromatic monomonos such as benzyl alcohol.

  The monool has 4 or more carbon atoms, preferably 5 or more, more preferably 6 or more, and usually 50 or less.

  Monools can be used alone or in combination of two or more.

  Of these monools, an aliphatic monool having 4 or more carbon atoms is preferable.

  In order to obtain an allophanate group-containing polyisocyanate, first, the equivalent ratio of the isocyanate group of the polyisocyanate to the hydroxyl group of the monool (isocyanate group / hydroxyl group) is, for example, 2 or more. Preferably, they are blended and reacted at a ratio of 5 or more, for example, 100 or less, preferably 50 or less.

  Monool and polyisocyanate can be reacted under known reaction conditions.

  Specifically, the reaction temperature is, for example, 40 ° C. or higher and 100 ° C. or lower, and the urethanization reaction is performed under reaction conditions of 0.5 hour or longer and 100 hours or shorter.

  Subsequently, the reaction temperature is, for example, 0 ° C. or higher, preferably 20 ° C. or higher, for example, 160 ° C. or lower, preferably 120 ° C. or lower, and the reaction time is 0.5 hour or longer and 20 hours or shorter. Then, the allophanatization reaction is performed.

  In the above urethanation reaction, a known urethanization catalyst (described later) can be added as necessary. In the above allophanatization reaction, a known allophanatization catalyst can be added as necessary. In each of the reactions described above, the above-described known organic solvent can be added as necessary.

  Examples of the allophanatization catalyst include organic carboxylic acid bismuth salts such as bismuth octylate, and organic carboxylic acid lead salts such as lead octylate.

  These allophanatization catalysts can be used alone or in combination of two or more.

  The mixing ratio of the allophanatization catalyst is not particularly limited, and is appropriately set according to the purpose and application.

  In addition, before the allophanate reaction described above, a cocatalyst such as an organic phosphite ester (for example, tris (tridecyl) phosphite) is added to the reaction system in advance, so that the allophanate catalyst and the cocatalyst can coexist The allophanatization reaction can also be carried out.

  Further, when the allophanatization reaction is terminated, the allophanatization catalyst is deactivated by adding a known allophanatization reaction terminator to the reaction system. Examples of the allophanatization reaction terminator include phosphoric acid, monochloroacetic acid, benzoyl chloride, dodecylbenzenesulfonic acid, paratoluenesulfonic acid, orthotoluenesulfonamide and the like.

  Further, when the concentration of unreacted monool or polyisocyanate (residual monomer concentration) in the reaction system after the reaction is high, preferably, the unreacted monomers are removed from the reaction system to reduce the residual monomer concentration.

  Examples of the method for removing unreacted monool and polyisocyanate include a distillation method such as a thin film distillation method and an extraction method such as a liquid-liquid extraction method. Preferably, a thin film distillation method is used.

  In the thin film distillation method, for example, the degree of vacuum is adjusted to 0.02 to 0.2 kPa and temperature conditions of 100 to 200 ° C.

  Thereby, allophanate group containing polyisocyanate can be obtained.

  The isocyanate group content (NCO%) of the allophanate group-containing polyisocyanate is, for example, 1 or more, preferably 5 or more, for example, 50 or less, preferably 30 or less.

  In the polydiene polyol, examples of the diene monomer include conjugated diene monomers such as butadiene, isoprene, chloroprene, cyanobutadiene, and pentadiene. Preferably, butadiene is used.

  These diene monomers can be used alone or in combination of two or more.

  The polymer of the diene monomer can be obtained by polymerizing the above diene monomer by a known polymerization method such as suspension polymerization, bulk polymerization, solution polymerization, emulsion polymerization or the like. Examples of such a polymer include polybutadiene, polyisoprene, polychloroprene, polycyanobutadiene, and polypentadiene.

  Further, the polydiene polyol can be obtained by modifying the molecular end of the polymer of the diene monomer to a hydroxyl group by a known method. Specifically, as such a polydiene polyol, for example, Examples include polybutadiene polyol, polyisoprene polyol, polychloroprene polyol, polycyanobutadiene polyol, polypentadiene polyol, and the like, preferably polyisoprene polyol and polybutadiene polyol, and more preferably polybutadiene polyol.

  If polybutadiene polyol is used, it is possible to ensure excellent resistance to high polar solvents and alkali resistance.

  The hydroxyl value of the polydiene polyol is, for example, 4 mgKOH / g or more, preferably 5 mgKOH / g or more, for example, 250 mgKOH / g or less, preferably 100 mgKOH / g or less.

  In addition, a hydroxyl value can be calculated | required from the acetylation method based on the A method or B method of JISK1557-1, the phthalation method, etc.

  The number average molecular weight of the polydiene polyol is, for example, 500 or more, preferably 2000 or more, more preferably 4000 or more, for example, 25000 or less, preferably 20000 or less, more preferably 15000 or less. .

  When the number average molecular weight of the polydiene polyol is in the above range, particularly 4000 or more, excellent resistance to a highly polar solvent and alkali resistance can be ensured.

  In addition, the measuring method of a number average molecular weight is explained in full detail in the following Example.

  Moreover, in manufacture of a polyurethane polyol, a low molecular weight polyol can be made to react with an allophanate group containing polyisocyanate with a polydiene polyol.

  The low molecular weight polyol is a compound having two or more hydroxyl groups and a number average molecular weight of less than 400, such as ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butylene glycol (1,4-butanediol). ), 1,3-butylene glycol, 1,2-butylene glycol, 1,5-pentamethylene glycol, 1,6-hexanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,2, 2-trimethylpentanediol, 3,3-dimethylolheptane, alkane (C7-22) diol, 1,3- or 1,4-cyclohexanedimethanol and mixtures thereof, 1,3- or 1,4-cyclohexanediol And mixtures thereof, hydrogenated bisphenol A, 1,4-dihy Dihydric alcohols (low molecular weight diols) such as loxy-2-butene, 2,6-dimethyl-1-octene-3,8-diol, bisphenol A, diethylene glycol, triethylene glycol, dipropylene glycol, such as glycerin, tri Trihydric alcohol (low molecular weight triol) such as methylolpropane, for example, tetrahydrol methane (pentaerythritol), tetrahydric alcohol such as diglycerin, for example, pentahydric alcohol such as xylitol, for example, sorbitol, mannitol, allitol, iditol, Examples include hexavalent alcohols such as dulcitol, altritol, inositol, and dipentaerythritol, for example, 7-valent alcohols such as perseitol, and octavalent alcohols such as sucrose.

  These low molecular weight polyols can be used alone or in combination of two or more.

  As the low molecular weight polyol, a dihydric alcohol (low molecular weight diol) is preferably used.

  In the production of a polyurethane polyol, if a low molecular weight diol is used (that is, if the polyol component contains a low molecular weight diol), excellent adhesiveness can be ensured.

  In the case where the low molecular weight polyol is contained in the polyol component, the content ratio of the low molecular weight polyol is, for example, 1 part by mass or more, preferably 5 parts by mass or more with respect to 100 parts by mass of the polydiene polyol. For example, it is 200 parts by mass or less, preferably 100 parts by mass or less.

  In order to obtain a polyurethane polyol, first, the above-described allophanate group-containing polyisocyanate and polydiene polyol (and, if necessary, a low molecular weight polyol) are mixed with the polydiene polyol (further, the isocyanate group of the allophanate group-containing polyisocyanate). If necessary, the equivalent ratio of hydroxyl groups (low molecular weight polyol) (hydroxyl group / isocyanate group) is, for example, a ratio exceeding 1, preferably 2 to 100, and they are urethanized.

  Allophanate group-containing polyisocyanate and polydiene polyol (and low molecular weight polyol if necessary) can be reacted under known reaction conditions. Specifically, the reaction temperature is, for example, 40 to 100 ° C. The urethanization reaction is performed under the reaction conditions of 0.5 to 100 hours.

  In the urethanization reaction described above, a known urethanization catalyst can be added as necessary, and the above-described organic solvent can be added as necessary.

  Examples of the urethanization catalyst include known urethanization catalysts such as amines and organometallic compounds.

  Examples of the amines include tertiary amines such as triethylamine, triethylenediamine, bis- (2-dimethylaminoethyl) ether, N-methylmorpholine, and quaternary ammonium salts such as tetraethylhydroxylammonium, such as imidazole, Examples thereof include imidazoles such as 2-ethyl-4-methylimidazole.

  Examples of organometallic compounds include tin acetate, tin octylate, tin oleate, tin laurate, dibutyltin diacetate, dimethyltin dilaurate, dibutyltin dilaurate, dibutyltin dimercaptide, dibutyltin maleate, dibutyltin dilaurate, dibutyltin Organic tin compounds such as dineodecanoate, dioctyltin dimercaptide, dioctyltin dilaurate, dibutyltin dichloride, for example, organic lead compounds such as lead octoate and lead naphthenate, for example, organic nickel compounds such as nickel naphthenate, For example, organic cobalt compounds such as cobalt naphthenate, for example, organic copper compounds such as copper octenoate, for example, organic bismuth compounds such as bismuth octylate and bismuth neodecanoate, zirconium octylate and zirconium neodecanoate Organic zirconium compounds such as titanium, zirconium tetraacetylacetonate, zirconium tributoxy monoacetylacetonate, zirconium dibutoxybis (ethylacetoacetate), organic titanium such as titanium tetraacetylacetonate, titanium tetra-2-ethylhexoxide Examples thereof include zinc compounds, organic zinc compounds such as zinc octylate, zinc neodecanoate, acetylacetone zinc, dibutyldithiocarbamate zinc, and p-toluenesulfonate zinc.

  These urethanization catalysts can be used alone or in combination of two or more.

  The blending ratio of the urethanization catalyst is not particularly limited, and is appropriately set according to the purpose and application.

  In this method, preferably, the disappearance of the isocyanate group is confirmed by a known method such as titration with di-n-butylamine or FT-IR analysis, and the end point of the reaction is determined.

  Thereby, the polyurethane polyol containing an allophanate group can be obtained.

  The number average molecular weight of the polyurethane polyol thus obtained is, for example, 550 to 45000, preferably 600 to 35000.

  The polyol component can be diluted with the above organic solvent.

  When the polyol component is diluted in an organic solvent, the solid content concentration of the polyol component is, for example, 10% by mass or more, preferably 30% by mass or more, for example, 95% by mass or less, preferably 90% by mass or less. is there.

  In addition, a polyol component can also be used without diluting with an organic solvent, ie, solid content concentration of 100 mass%.

  In addition, other polyols, specifically, for example, the above-described low molecular weight polyols, for example, the above-mentioned polydiene polyols and hydrogenated products thereof are added to the polyol component separately from the polyurethane polyols. You can also.

  In such a case, the mixing ratio of the other polyol is, for example, 1 part by mass or more, preferably 5 parts by mass or more, for example, 100 parts by mass or less, preferably 100 parts by mass of the polyurethane polyol. 90 parts by mass or less.

  And in the adhesive for lamination of this invention, a polyisocyanate component and a polyol component are mix | blended at the time of the lamination process mentioned later, and it mixes and stirs and uses it.

  The mixing ratio of the polyisocyanate component and the polyol component is such that the equivalent ratio of the isocyanate group of the polyisocyanate component to the hydroxyl group of the polyol component (isocyanate group / hydroxyl group) is, for example, 0.4 or more, preferably 0.5 or more. For example, the ratio is adjusted to 10.0 or less, preferably 5.0 or less.

  In addition, the polyisocyanate component and the polyol component may include, for example, an epoxy resin, a curing catalyst, a coating improver, a leveling agent, an antifoaming agent, an antioxidant, You may mix | blend additives, such as stabilizers, such as a ultraviolet absorber, a plasticizer, surfactant, a pigment, a filler, organic or inorganic microparticles, an antifungal agent, and a silane coupling agent. The mixing ratio of these additives is appropriately determined depending on the purpose and application.

  The laminating adhesive is used for laminating a composite film, specifically, bonding between each film of the composite film.

  That is, in laminating, for example, after diluting and blending a polyisocyanate component and a polyol component with a known organic solvent to prepare a laminating adhesive, the laminating adhesive is applied to each film surface by a solvent laminator. After coating and volatilizing the solvent, the coated surfaces are bonded together, and then cured at room temperature or under heating, or the blending viscosity of the polyisocyanate component and the polyol component is from room temperature to 100 ° C. For example, in the case of about 100 to 10000 mPa · s, preferably about 100 to 5000 mPa · s, for example, a polyisocyanate component and a polyol component are blended as they are to prepare an adhesive for lamination, and then a solventless type This laminating adhesive is applied to each film surface with a laminator. Bonding the coated surface, then, a method of curing by curing at room temperature or under heating is employed.

Usually, for example, in the case of a solvent type, the coating amount is about 2.0 to 8.0 g / m ² in basis weight (solid content) after solvent evaporation, about 1.0 to ³ in a solventless type. 0.0 g / m ² .

  Examples of films to be adhered include plastic films made of polyethylene terephthalate, nylon, polyethylene, polypropylene (for example, unstretched polypropylene or stretched polypropylene), polyvinyl chloride, polyvinylidene chloride, etc., for example, aluminum, stainless steel, iron, copper And metal foil made of lead and the like. Further, the surface of the above-described film can be subjected to known activation treatment such as corona treatment, UV treatment, plasma treatment, etc., if necessary.

  The thickness of each film is, for example, 5 μm or more, preferably 9 μm or more, for example, 200 μm or less, preferably 100 μm or less.

  The laminating adhesive of the present invention is excellent in resistance to highly polar solvents, and therefore, when containing a highly polar solvent, the adhesive can be maintained for a long time even at high temperatures. Since it is excellent in alkalinity, it can also be used when a strongly alkaline solution is accommodated.

  Moreover, the composite film in which the adhesive for laminating was used for adhesion between the films was 168 hours at 85 ° C. in a mixed solvent containing ethylene carbonate, diethyl carbonate and dimethyl carbonate in a mass ratio of 1/1/1. The adhesive strength after immersion (immediately after) is, for example, 1.0 N / 15 mm or more, preferably 1.5 N / 15 mm or more, more preferably 2.0 N / 15 mm or more, and usually 20 N / 15 mm or less. is there.

  Further, the adhesive strength after being immersed and dried for 24 hours as described above is, for example, 3.5 N / 15 mm or more, preferably 5.0 N / 15 mm or more, and more preferably 6.5 N / 15 mm or more. Yes, usually 20 N / 15 mm or less.

  In addition, the adhesive strength of the composite film before dipping, that is, immediately after laminating is, for example, 2.0 N / 15 mm or more, preferably 4.0 N / 15 mm or more, more preferably 6.0 N / 15 mm or more, Usually, it is 20 N / 15 mm or less.

  And the composite film in which the adhesive agent for lamination was used for adhesion | attachment between each film is excellent in alkali resistance. Specifically, the composite film in which the adhesive for laminating was used for adhesion between the films was heat-sealed and filled with a strongly alkaline (for example, pH 10.0 to 14.0) solution. Even when stored for a week, an excellent appearance can be maintained without causing delamination.

  In such a case, the adhesive strength of the composite film is, for example, 2.0 N / 15 mm or more, preferably 3.0 N / 15 mm or more, more preferably 4.0 N / 15 mm or more, and usually 20 N / It is 15 mm or less.

  The method for measuring the adhesive strength of the composite film described above will be described in detail in the following examples.

  Therefore, the above-mentioned composite film is used as, for example, a packaging bag used in various industrial fields that enclose an alkaline solution, and specifically, food, beverages, agricultural chemicals, pharmaceuticals, quasi drugs, and the like. It is used as a packaging bag or an exterior bag for electronic parts, and further as an exterior bag for a secondary battery such as a lithium ion battery.

  The composite film obtained by adhering each film using the laminating adhesive of the present invention is excellent in resistance to highly polar solvents, and therefore, even when containing highly polar solvents, it is long even at high temperatures. Its adhesive strength can be maintained over time.

  Moreover, since the composite film obtained by adhere | attaching between each film using the adhesive agent for lamination of this invention is excellent also in alkali resistance, it can be used also when accommodating a strong alkaline solution.

  Furthermore, the adhesive for lamination of the present invention has excellent adhesive strength between the film and the adhesive layer.

  Therefore, according to the laminating adhesive of the present invention, a packaging bag having excellent reliability can be obtained.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but these do not limit the present invention in any way. “Part” and “%” are based on mass unless otherwise specified.

  Moreover, the number average molecular weight described below was measured as follows.

That is, after dissolving 40 mg of a sample in 4 mL of tetrahydrofuran and preparing it as a 1 w / v% solution, it was measured by gel permeation chromatography (GPC) under the following conditions, and the number average molecular weight (Mn) was calculated in terms of standard polystyrene. It was measured.
Data processing device: product number EMPOWER2 (manufactured by Waters)
Differential refractive index detector: 2414 type differential refractive detector column: PLgel 5 μmMixed-C product number 1110-6500 (manufactured by Polymer Laboratories) 3 mobile phases: tetrahydrofuran column flow rate: 1 mL / min
Sample concentration: 10 g / L
Injection volume: 100 μL
Measurement temperature: 40 ° C
Molecular weight calibration: TSK standard Polystyrene manufactured by TOSOH
<Preparation of polyisocyanate component>
Preparation Example 1
(Preparation of polyisocyanate component A)
Tolylene diisocyanate modified ("Takenate D-103H", alcohol modified with trimethylolpropane, average functional group number 3 or more, isocyanate group content 12.6%, solid content 75% (ethyl acetate solvent), Mitsui Chemicals, Inc. Manufactured) was designated as polyisocyanate component A.

Preparation Example 2
(Preparation of polyisocyanate component B)
250.0 g of toluene is added to 750 g of a hexamethylene diisocyanate modified (“Takenate D-170N”, trimer, average functional group number 3 or more, isocyanate group content 21.0%, manufactured by Mitsui Chemicals, Inc.), and mixed uniformly. As a result, a polyisocyanate component B having a solid content of 75% and an isocyanate group content of 15.8% was prepared.

Preparation Example 3
(Preparation of polyisocyanate component C)
Tolylene diisocyanate monomer (“Cosmonate T-80”, 2,4-isomer / 2,6-isomer ratio = 80/20 tolylene diisocyanate, average number of functional groups 2, manufactured by Mitsui Chemicals, Inc.) Was polyisocyanate component C.
<Synthesis of allophanate group-containing polyisocyanate>
Synthesis example 1
(Synthesis of polyisocyanate a)
In a 4-liter flask having a capacity of 1 liter equipped with a stirrer, a thermometer, a condenser, and a nitrogen gas introduction tube, 860 g of hexamethylene diisocyanate (HDI), 139.5 g of octadecanol, and tris (tridecyl) were added under a nitrogen atmosphere. 0.5 g of phosphite was charged and urethanized at 80 ° C. for 2 hours. Next, 0.05 g of bismuth octylate (Bi content: 18% by mass) was added to the reaction solution, and an allophanatization reaction was performed at 100 ° C. for 10 hours, indicating that the conversion of urethane bonds to allophanate bonds was almost complete. Confirmed by FT-IR, 0.03 g of orthotoluenesulfonamide was added to stop the allophanatization reaction.

  Unreacted octadecanol and hexamethylene diisocyanate were removed from the resulting reaction solution using a thin-film distillation apparatus (degree of vacuum: 0.05 kPa, temperature 150 ° C.), and allophanate group-containing polyisocyanate (HDI / C18OH allophanate modified product) To obtain a polyisocyanate a. The isocyanate group content (NCO%) of polyisocyanate a was 13.1%.

NCO% was measured by an isocyanate group content test described in JIS K7301.
<Synthesis of polyurethane polyol>
Synthesis example 2
(Synthesis of polyol a)
Polybutadiene polyol (“Poly bd R-45HT”, hydroxyl value 46.6 mg KOH / g, molecular weight 4877, manufactured by Idemitsu Kosan Co., Ltd.) 270.4 g, ethylene glycol 27.2 g, polyisocyanate a 302.4 g were added, respectively, and nitrogen stream Then, the urethanization reaction was carried out for 1 hour while adjusting the reaction temperature in the range of 60 to 70 ° C. Next, 0.06 g of tin octylate was added to the reaction solution, and a urethanization reaction was further performed while adjusting the reaction temperature in the range of 70 to 80 ° C. Reaction was carried out by FT-IR until the peak of the isocyanate group disappeared completely to obtain polyol a.

Synthesis example 3
(Synthesis of polyol b)
159.8 g of polybutadiene polyol (“Poly bd R-15HT”, hydroxyl value 102.7 mg KOH / g, molecular weight 2281, manufactured by Idemitsu Kosan Co., Ltd.), 36.2 g of ethylene glycol, 404.0 g of polyisocyanate a were added, and a nitrogen stream was added. Then, the urethanization reaction was carried out for 1 hour while adjusting the reaction temperature in the range of 60 to 70 ° C. Next, 0.06 g of tin octylate was added to the reaction solution, and a urethanization reaction was further performed while adjusting the reaction temperature in the range of 70 to 80 ° C. Reaction was carried out by FT-IR until the peak of the isocyanate group completely disappeared to obtain polyol b.

Synthesis example 4
(Synthesis of polyol c)
Polyisoprene polyol (“Poly ip”, hydroxyl value 46.6 mg KOH / g, molecular weight 4162, manufactured by Idemitsu Kosan Co., Ltd.) 270.4 g, ethylene glycol 27.2 g, and polyisocyanate a 302.4 g were added, respectively, The urethanization reaction was carried out for 1 hour while adjusting the reaction temperature within the range of 60 to 70 ° C. Next, 0.06 g of tin octylate was added to the reaction solution, and a urethanization reaction was further performed while adjusting the reaction temperature in the range of 70 to 80 ° C. Reaction was carried out until the peak of the isocyanate group disappeared completely by FT-IR to obtain polyol c.

Synthesis example 5
(Synthesis of polyol d)
"Poly bd R-45HT" 518.2g and polyisocyanate a81.8g were added, respectively, and urethanation reaction was performed for 1 hour, adjusting reaction temperature in the range of 60-70 degreeC under nitrogen stream. Next, 0.06 g of tin octylate was added to the reaction solution, and a urethanization reaction was further performed while adjusting the reaction temperature in the range of 70 to 80 ° C. The reaction was carried out by FT-IR until the isocyanate group peak completely disappeared to obtain polyol d.

Synthesis Example 6
(Synthesis of polyol e)
Add 390.7 g of dimethyl 2,6-naphthalenedicarboxylate (NDCM), 67.3 g of propylene glycol (PG), 137.5 g of neopentyl glycol (NPG), and 0.1 g of titanium tetrabutoxide, respectively, under a nitrogen stream The transesterification reaction was carried out at 180 to 220 ° C. After distilling a predetermined amount of methanol, the inside of the system was gradually depressurized and subjected to a condensation reaction at 13.3 Pa or less and 220 ° C. to form a naphthalenedicarboxylic acid-containing polyester polyol (NDCM // PG / NP) having a number average molecular weight of about 5000. A polyol e consisting of NPG) was obtained.

Synthesis example 7
(Synthesis of polyol f)
In a four-necked flask with a capacity of 1 liter equipped with a stirrer, thermometer, condenser and nitrogen gas inlet tube, 314 g of polyoxypropylene glycol ("Diol-1000", number average molecular weight 1000, manufactured by Mitsui Chemicals, Inc.) 36 g of propylene glycol, 147 g of polyisocyanate a and 81 g of Cosmonate T-80 were charged, and the urethanization reaction was performed for 1 hour while adjusting the reaction temperature in the range of 60 to 70 ° C. in a nitrogen stream. Next, 0.06 g of tin octylate was added to the reaction solution, and the urethanization reaction was further performed for 4 hours while adjusting the reaction temperature in the range of 70 to 80 ° C. Thereafter, 22 g of 1,4-butylene glycol and 0.12 g of tin octylate were added. Reaction was carried out until the peak of the isocyanate group disappeared completely by FT-IR to obtain polyol f.

<Preparation of polyol component>
Preparation Examples 4 to 10
(Preparation of polyol components A to F)
600 g of polyols a to f of Synthesis Examples 2 to 8 were diluted with 400 g of toluene to prepare polyol components A to F of Preparation Examples 4 to 10 having a solid content of 60%.

Preparation Example 12
(Preparation of polyol component G)
“Poly bd R-45HT” was used as the polyol component G.
<Production of composite film>
Example 1
750 parts by mass of polyol component A was mixed with 100 parts by mass of polyisocyanate component A to obtain an adhesive for laminating. Dilute the laminating adhesive with toluene, and apply it on a 40 μm thick aluminum foil (untreated surface) at room temperature to a basis weight of 4 g / m ² (solid content) using a bar coater. The organic solvent was stripped. Then, the laminating adhesive surface on the aluminum foil and the corona-treated surface of an unstretched polypropylene film (single-sided corona-treated product) with a thickness of 60 μm are bonded together and cured at 60 ° C. for 5 days. The composite was cured by curing the aluminum foil and the unstretched polypropylene film.

Moreover, the adhesive for laminating is diluted with toluene, and a corona-treated surface in a nylon film (single-sided corona-treated product) having a thickness of 15 μm so as to have a basis weight of 3.5 g / m ² (solid content) using a bar coater. The organic solvent was volatilized by coating at room temperature. Then, the coated surface of the adhesive for laminating on the nylon film and the corona-treated surface of an unstretched polyethylene film (single-sided corona treatment) having a thickness of 130 μm are bonded together and cured at 40 ° C. for 5 days, whereby the laminating adhesive is obtained. The composite film II was obtained by curing and bonding between the nylon film and the unstretched polyethylene film.

Example 2
Composite film I and composite film II were obtained in the same manner as in Example 1, except that polyisocyanate component B was used instead of polyisocyanate component A in Example 1.

Examples 3-5
A composite film I and a composite film II were obtained in the same manner as in Example 1 except that the polyol components B to D were used instead of the polyol component A of Example 1.

Example 6
Example 100 was used in the same manner as in Example 1 except that 100 parts by mass of polyisocyanate component C in Example 1 was used instead of 100 parts by mass of polyisocyanate component A, and 3000 parts by mass of polyol component A was used in place of 750 parts by mass of polyol component A. Thus, composite film I and composite film II were obtained.

Comparative Examples 1 and 2
A composite film I and a composite film II were obtained in the same manner as in Example 1 except that the polyol components E and F were used instead of the polyol component A of Example 1.

Comparative Example 3
Composite film I and composite film II were obtained in the same manner as in Example 1, except that 250 parts by mass of polyol component G was used instead of 750 parts by mass of polyol component A in Example 1.

(Evaluation)
(1) Adhesive strength Composite films I and II were cut out to a size of 150 mm in length and 15 mm in width, and a T-type peel test was carried out at a crosshead speed of 300 mm / min using a universal tension measuring device. The adhesive strength of the film was measured. The results are shown in Tables 1 and 2. Moreover, the fracture mode at the time of peeling is shown together.
(2) Content resistance test 1
The composite film I was immersed in a mixed solvent containing ethylene carbonate, diethyl carbonate and dimethyl carbonate at a 1/1/1 mass ratio at 85 ° C. for 168 hours. After immersion, the composite film was taken out and the mixed solvent was wiped off. Thereafter, a T-type peel test was performed immediately using a universal tension measuring device at a crosshead speed of 300 mm / min, and the adhesive strength of the composite film after immersion was measured. Further, after the mixed solvent was wiped off and dried for 24 hours, the adhesive strength of the composite film was measured in the same manner. The results are shown in Tables 1 and 2. Moreover, the fracture mode at the time of peeling is shown together.
(3) Content resistance test 2
One end of the composite film II was heat-sealed to prepare a 170 mm × 65 mm pouch, and this pouch was filled with a strong alkaline detergent (“Magicrin”, manufactured by Kao Corporation). This was stored at 50 ° C. for 2 weeks, and the appearance of the pouch after storage was observed. Further, the adhesive strength of the pouch after storage (composite film II) was measured in the same manner as in the adhesive test. The results are shown in Tables 1 and 2. Moreover, the fracture mode at the time of peeling is shown together.

The details of the abbreviations in the table are as follows.
TDI adduct: Alcohol modified product of tolylene diisocyanate with trimethylolpropane, average number of functional groups of 3 or more, Takenate D-103H (Mitsui Chemicals, Inc.)
HDI trimer: trimer of hexamethylene diisocyanate, average number of functional groups of 3 or more, Takenate D-170N (manufactured by Mitsui Chemicals, Inc.)
TDI monomer: monomer of tolylene diisocyanate (2,4-isomer / 2,6-isomer ratio = 80/20), average number of functional groups 2, Cosmonate T-80 (manufactured by Mitsui Chemicals, Inc.)
HDI allophanate: Polyisocyanate a obtained in Synthesis Example 1 (modified HDI / C18OH allophanate)
Naphthalene-containing allophanate: Polyol e obtained in Synthesis Example 6 (Naphthalenedicarboxylic acid-containing polyester polyol (NDCM // PG / NPG))
PPG: Polyoxypropylene glycol, Diol-1000 (Mitsui Chemicals)
Details of the abbreviations in the fracture mode at the time of peeling are as follows.
Ad: Adhesive for laminating CPP: Unstretched polypropylene film AL: Aluminum foil NY: Nylon film LLDPE: Unstretched polyethylene film “: (colon)” in the table is an interface in the layers (interfaces) described on both sides Indicates that it was peeled off.

  In addition, “NY surface peeling” indicates that the laminate was peeled between the laminating adhesive and the nylon film, but the surface layer of the nylon film was thinly attached to the laminating adhesive, and “NY cut” was peeled off. Indicates that the nylon film layer was broken during the test.

Claims (6)

A laminating adhesive containing a polyisocyanate component and a polyol component,
The polyol component is
A laminate adhesive comprising a polyurethane polyol obtained by reacting an allophanate group-containing polyisocyanate with a polymer of a diene monomer having a hydroxyl group at a molecular end.   The laminate adhesive according to claim 1, wherein the average number of functional groups of the polyisocyanate component is more than two.   The laminate adhesive according to claim 1 or 2, wherein the number average molecular weight of the polymer is 4000 or more.   The laminate adhesive according to any one of claims 1 to 3, wherein the polymer is a polybutadiene polyol.   The laminate adhesive according to any one of claims 1 to 4, wherein the polyol component contains a low molecular weight diol.   The laminate adhesive according to any one of claims 1 to 5, wherein the polyisocyanate component contains a modified aromatic diisocyanate.