JPWO2019116903A1 - Solventless laminating adhesive, cured product thereof, laminate and package - Google Patents

Abstract

A non-solvent type laminating adhesive comprising a polyisocyanate component (A) and a polyol component (B) as essential components, wherein the polyol component (B) has a number average molecular weight of 1,000 or less and a tetra- or higher functional sugar alcohol or sugar. Solventless laminating adhesive containing polyol (b1) which is an alcohol derivative and polyalkylene glycol (b2) having a primary hydroxyl group and having a number average molecular weight of 2,500 to 7,000, said solventless laminating adhesive And a package using the laminate.

Description

  The present invention relates to a solventless laminating adhesive, and a laminate and a package using the same.

  Laminated films (also referred to as laminated bodies or laminated films) used for various packaging materials, labels, and the like are made of various kinds of plastic films, metal foils, papers, and the like, and are designed, designed, functionalized, and preserved. Convenience and transportability are imparted, and a package formed by molding the laminated film into a bag shape is used as a package for foods, pharmaceuticals, detergents, and the like.

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

  The solventless laminating adhesive has many advantages, such as no need to consider the residual solvent in the laminated film, and no need for a drying step. On the other hand, in the case of application using a roll coater which is a general-purpose application method, stringing is likely to occur between the film coated with the adhesive and the coater. In this case, if the adhesive in the form of a thread scatters and re-adheres to the already-coated surface, there are problems that the coated surface becomes rough and that the adhesive layer becomes easily trapped by air, thereby lowering the appearance of the laminated film. In particular, the decrease in the appearance of the laminated film due to air entrapment becomes more pronounced as the viscosity of the adhesive itself increases. Therefore, the viscosity of the solventless adhesive is limited, and the resin is generally designed to have a smaller molecular weight than the solvent type adhesive. However, when the molecular weight becomes small, there is a drawback that a time until sufficient adhesive strength and heat resistance are developed after lamination becomes long, and a long aging time is required. In addition, there is also a problem that the pot life after blending the main agent and the curing agent is shortened because of not involving the solvent.

  As a method of shortening the aging time of such a solventless adhesive, a method of combining an aromatic diisocyanate as a main agent and a polyester diol and a low molecular weight diol such as diethylene glycol as a curing agent is known (for example, Patent Document 1). reference). However, the adhesive of the combination of the aromatic isocyanate and the polyester diol still has a high viscosity, and therefore has a drawback that air bubbles are likely to be mixed in by air entrapment, especially during high-speed lamination. As a method for improving this, Patent Literature 2 discloses a method in which a castor oil or a castor oil derivative containing a hydroxyl group, a polyol containing polyalkylene glycol having a number average molecular weight of 2,500 to 7,000 and a polyisocyanate are combined. (For example, see Patent Document 2). According to this method, the appearance of the laminated film after lamination is good, and particularly, good appearance can be maintained even when high-speed lamination is performed. However, there is still room for improvement from the viewpoint of adhesive coating work and the like.

JP 2014-159548 A WO2016 / 152370

  The problem to be solved by the present invention is to use a solventless laminating adhesive in which the pot life after mixing the polyol and the isocyanate is stable, and which can complete aging in a shorter time after lamination, and the adhesive. It is to provide a laminate and a package.

Usually, a two-liquid solventless laminating adhesive containing the polyisocyanate component (A) and the polyol component (B) as essential components flows in two liquids, and the two liquids are mixed during the adhesive coating operation. After mixing, the reaction between the polyol and the isocyanate starts, but if the reaction rate is too high or not constant, the operation is hindered. In general, it is determined that the pot life is stable if the change in viscosity after 30 minutes at 40 ° C. after mixing the two liquids is small.
The present inventors diligently studied a combination of an isocyanate and a polyol which may cause a reaction rate, and as a result, as the polyol component (B), a tetrafunctional or more functional polyol (b1) having a number average molecular weight of 1,000 or less and a primary When a combination of a polyalkylene glycol (b2) having a hydroxyl group and a number average molecular weight of 2,500 to 7,000 is used in combination, the reaction rates of the polyol (b1) and the polyalkylene glycol (b2) with the respective isocyanates are different. To be presumed, it was found that an adhesive with a stable pot life could be obtained.

That is, the present invention is a solventless laminating adhesive comprising a polyisocyanate component (A) and a polyol component (B) as essential components,
The polyol component (B) is a polyol (b1), which is a sugar alcohol or sugar alcohol derivative having a number average molecular weight of 1,000 or less and having a functionality of 4 or more, and a polyalkylene having a number average molecular weight of 2,500 to 7,000 having a primary hydroxyl group. Provided is a solventless laminate adhesive containing glycol (b2).

  The present invention also provides a cured product obtained by curing the above-described solventless laminating adhesive.

  The present invention also provides a laminate using the above-described solventless laminating adhesive for an adhesive layer.

  The present invention also provides a package using the above-described laminate.

  According to the present invention, a solvent-free laminating adhesive having a stable pot life after mixing a polyol and an isocyanate and capable of completing aging in a shorter time after lamination, a laminate using the adhesive, and packaging Can provide body.

(Definition of solvent)
The solventless laminating adhesive of the present invention is a reactive two-pack type laminating adhesive as described above. Since no conventional volatile organic solvent is used, it is called a solventless type.
In the present invention, an adhesive that is cured by a chemical reaction between an isocyanate group and a hydroxyl group is used. The “solvent” of the solventless adhesive according to the present invention refers to a highly soluble and volatile organic solvent capable of dissolving the polyisocyanate or the polyol used in the present invention. "Means not containing these highly soluble organic solvents. Specific examples of highly soluble organic solvents include toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, acetone, methyl ethyl ketone (MEK), cyclohexanone, toluene, and xylol. , N-hexane, cyclohexane and the like. Among them, toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, and ethyl acetate are known as organic solvents having particularly high solubility.

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

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

(Polyol component (B))
The polyol component (B) used in the present invention is a 4-functional or more polyol (b1) having a number average molecular weight of 1000 or less, and a polyalkylene glycol (b2) having a primary hydroxyl group and a number average molecular weight of 2,500 to 7,000. And

(Polyfunctional or higher functional polyol (b1) having a number average molecular weight of 1,000 or less)
In the polyol (b1) having four or more functional groups having a number average molecular weight of 1,000 or less used in the present invention, the functional group represents a hydroxyl group, and the number of functional groups represents the number of hydroxyl groups.
In the present application, it is preferable to use a sugar alcohol or a sugar alcohol derivative as the polyol (b1). Note that a sugar alcohol derivative refers to a compound in which some hydroxyl groups have become a salt or a compound in which some hydroxyl groups have reacted with another functional group.
Specifically, sugar alcohols include pentaerythritol, sucrose, xylitol, sorbitol, isomalt, lactitol, maltitol, mannitol and the like.
Examples of the sugar alcohol derivatives include, for example, ethylene oxide adducts, propylene oxide adducts, and butylenes obtained by addition reaction of the sugar alcohols with polyoxyalkylenes such as polyoxyethylene (POE), polyoxypropylene (POP), and polyoxybutylene. And alkylene oxide adducts such as oxide adducts.
Among them, a polyol having six or more functional groups is preferable because aging can be completed in a short time because a crosslinked structure is formed in a short time.

(Polyalkylene glycol having a number average molecular weight of 2,500 to 7,000 having a primary hydroxyl group (b2))
Examples of the polyalkylene glycol (b2) having a primary hydroxyl group and having a number average molecular weight of 2,500 to 7,000 used in the present invention include, for example, polyethylene glycol which is a polymer of ethylene oxide and polypropylene which is a polymer of propylene oxide Glycol, polybutylene glycol which is a polymer of butylene oxide, polypropylene glycol, and ethylene oxide adduct of polybutylene glycol end, and the like. These polyalkylene glycols can be produced by polymerizing each alkylene glycol using water or alcohol as an initiator.

  Examples of the alcohol that can be used as the initiator herein include ethylene glycol, diethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, , 5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol Glycols such as dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and triethylene glycol ; And glycerin, trimethylolpropane, pentaerythritol, and polyfunctional alcohols having three or more functional like sorbitol.

  In the present invention, the polyalkylene glycol (b2) has a number average molecular weight (Mn) in the range of 2,500 to 7,000. By selecting one having a number average molecular weight (Mn) of 2,500 or more, the elastic modulus of the adhesive is increased, and the movement and aggregation of air bubbles that have entered the adhesive during lamination can be effectively suppressed. On the other hand, by setting the number average molecular weight (Mn) to 7,000 or less, it is possible to prevent the viscosity of the adhesive from becoming excessively high, and the workability as a solventless adhesive becomes excellent. Among these, the number average molecular weight (Mn) is preferably in the range of 3,000 to 7,000, in particular, from the viewpoint that the appearance of the laminate during high-speed lamination processing becomes favorable.

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

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

  The mixing ratio of the polyol (b1) and the polyalkylene glycol (b2) is preferably in the range of (b1) :( b2) = 10/90 to 60/40. Within this range, the composition is cured by aging for a short time, and the pot life becomes stable.

(Other polyol components (B)
In the present invention, as the polyol component (B), a general-purpose polyol may be used in addition to the polyol (b1) and the polyalkylene glycol (b2) as long as the effects of the present invention are not impaired. Other polyol components include ethylene glycol, propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 3-methyl-1 , 5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxy Glycols such as ethoxybenzene, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, and triethylene glycol; bisphenol A, bisphenol F, hydrogenated bisphenol A, bisphenols such as hydrogenated bisphenol F; dimer diols; polyalkylene glycols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as the above-mentioned glycol. A urethane bond-containing polyether polyol obtained by further increasing the molecular weight of the polyalkylene glycol with the aromatic or aliphatic polyisocyanate; propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, β-methyl-σ-valerolactone Polyester obtained by a ring-opening polymerization reaction of a cyclic ester compound such as glycol and a polyhydric alcohol such as glycol, glycerin, trimethylolpropane, pentaerythritol, etc. And polyester polyol which is a reaction product with the polyester. These other polyol components are desirably 10% by mass or less in the polyol component (B).

Further, when castor oil or a castor oil derivative containing a hydroxyl group is used in combination, the appearance of the laminated product after lamination is good, and in particular, good appearance can be maintained even when high-speed lamination is performed.
Here, commercially available caster oil can be used. Further, as the hydroxyl group-containing castor oil derivative, dehydrated castor oil, castor oil, hydrogenated castor oil, castor oil fatty acid, dehydrated castor oil fatty acid, castor oil fatty acid condensate, castor oil ethylene oxide 5 to 50 mol adduct, or castor oil-based polyol Is mentioned. Among them, castor oil is particularly preferable because it can reduce the viscosity of the adhesive.

When castor oil or a castor oil derivative containing a hydroxyl group is used in combination, the composition ratio is preferably 10% by mass or more based on the total of the polyisocyanate component (A) and the polyol component (B).
The final mass ratio of castor oil or the hydroxyl group-containing castor oil derivative (b1) to polyalkylene glycol (b2) is such that the mass ratio [(b1) / (b2)] is 90/10 to 20/80. It is preferable from the viewpoint of the appearance of the laminated product obtained from the viewpoint and prevention of misting. Among these, the number average molecular weight (Mn) of the polyalkylene glycol (b2) is 2,800 to improve the productivity of the laminate, even in the case of high-speed lamination, from which a good appearance of the laminate can be obtained. 6,000, and the mass ratio [(b1) / (b2)] of castor oil or a hydroxyl group-containing castor oil derivative (b1) to polyalkylene glycol (b2) is 75/25 to 25/75. It is preferably a ratio.

(Polyisocyanate component (A))
The polyisocyanate component (A) used as a main component in the present invention includes, for example, aromatic polyisocyanates such as tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, 1,5-naphthalenediisocyanate, and triphenylmethane triisocyanate; -Aliphatic polyisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-methylenebis (cyclohexyl isocyanate), lysine diisocyanate, trimethylhexamethylene diisocyanate, and 1,3- (isocyanatomethyl) cyclohexane; Polyisocyanate which is a reaction product of an aromatic polyisocyanate and a polyol; Examples thereof include ret bodies, derivatives (modified products) of polyisocyanates such as isocyanurates of these aromatic or aliphatic polyisocyanates, and adducts obtained by modifying these aromatic or aliphatic polyisocyanates with trimethylolpropane. .

  Here, as the polyol used for the reaction with the aromatic or aliphatic polyisocyanate, specifically, ethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutanediol, butylethylpropanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol, etc. Bisphenols such as bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F; dimer diol; bishydroxyethoxybenzene; diethylene glycol, triethylene glycol; Other polyalkylene glycols such as polyethylene glycol, polypropylene glycol and polybutylene glycol; urethane bond-containing polyether polyols obtained by further increasing the molecular weight of the polyalkylene glycol with the aromatic or aliphatic polyisocyanate; the alkylene glycol or polyalkylene Glycol has carbon atoms such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, fumaric acid, maleic acid, suberic acid, azelaic acid, sebacic acid, undecandioic acid, dodecandioic acid, tridecandioic acid, etc. Polyester polyols obtained by reacting aliphatic dicarboxylic acids in the range of 2 to 13; cyclic esters such as propiolactone, butyrolactone, ε-caprolactone, σ-valerolactone, and β-methyl-σ-valerolactone Examples of the polyester polyol include a polyester obtained by a ring-opening polymerization reaction of a compound and a polyhydric alcohol such as glycol, glycerin, trimethylolpropane, and pentaerythritol.

  As the polyol used for the reaction with the aromatic or aliphatic polyisocyanate, among these, a polyalkylene glycol or a polyester polyol is preferable because the adhesive strength can be increased while reducing the viscosity of the adhesive itself. The polyalkylene glycol preferably has a number average molecular weight (Mn) in the range of 200 to 6,000. On the other hand, the polyester polyol is preferably obtained by reacting the alkylene glycol or the polyalkylene glycol having a molecular weight of 300 or less with an aliphatic polycarboxylic acid having 2 to 30 carbon atoms. In the latter polyester polyol, a tri- or higher functional alcohol such as glycerin, trimethylolpropane or pentaerythritol may be used as a raw alcohol component in a proportion of 10% by mass or less in the polyol component.

  Among the polyisocyanate components (A) described above in detail, for a soft packaging base material, a polyisocyanate obtained by reacting an aromatic polyisocyanate with a polyalkylene glycol having a number average molecular weight in the range of 200 to 6,000, A polyisocyanate obtained by reacting an aromatic polyisocyanate with a polyester polyol having a number average molecular weight in the range of 200 to 3,000 is preferable because it can impart appropriate flexibility to the cured product. Those having an isocyanate content of 5 to 20% by mass (using di-n-butylamine) are preferable because they have an appropriate resin viscosity and are excellent in coatability.

  On the other hand, for a hard base material of a solventless adhesive, a polyisocyanate obtained by reacting an aromatic polyisocyanate with a polyester polyol having a number average molecular weight in the range of 200 to 3,000; Polyisocyanates obtained by reacting a mixture of a polyester polyol having a molecular weight in the range of 200 to 3,000 and a polyalkylene glycol having a number average molecular weight in the range of 200 to 6,000 are preferred from the viewpoint of excellent adhesive strength, and Among them, those having an isocyanate content of 5 to 20% by mass by a titration method (using di-n-butylamine) are preferable because they also have an appropriate resin viscosity and are excellent in coatability.

  Here, the reaction ratio of the mixture of the aromatic polyisocyanate and the polyalkylene glycol or the polyester polyol is such that the equivalent ratio [isocyanate / hydroxyl group] of the isocyanate in the aromatic polyisocyanate to the hydroxyl group in the polyol is 1.5 to 1.5. The range of 5.0 is preferable from the viewpoint that the viscosity of the adhesive is in an appropriate range and the coating property is good.

  Further, in the solventless laminate adhesive of the present invention, the ratio of the polyisocyanate component (A) and the polyol component (B) used is as follows: the isocyanate group in the polyisocyanate component (A) and the polyol component. The equivalent ratio [isocyanate group / hydroxyl group] to the hydroxyl group in (B) is appropriately selected usually in a range where the isocyanate group is excessive in consideration of the fact that the isocyanate group is consumed by moisture or active hydrogen in the printing ink. For example, the ratio is preferably 1.0 to 5.0, and particularly preferably 1.5 to 3.5, from the viewpoint that the degree of crosslinking becomes appropriate and the heat resistance becomes good. preferable.

  As described in detail, the solventless laminating adhesive of the present invention contains the polyisocyanate component (A) and the polyol component (B) as essential components. A harmful low molecule represented by an aromatic amine in a laminate package by being mixed with either one of the component (A) and the polyol component (B), or being compounded at the time of coating as a third component. Elution of the chemical substance into the contents can be effectively suppressed.

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

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

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

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

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

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

  The mass ratio of the pigment used in the present invention is 1 to 400 parts by mass, preferably 10 to 300 parts by mass, based on 100 parts by mass of the total of the polyisocyanate component (A) and the polyol component (B). It is more preferable because of its excellent blocking resistance and the like.

  Further, an adhesion promoter may be used in the solventless laminate adhesive of the present invention. Examples of the adhesion promoter include a silane coupling agent, a titanate-based coupling agent, an aluminum-based coupling agent, an epoxy resin, a polybasic acid anhydride, phosphoric acids, and phosphoric esters.

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

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

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

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

Examples of polybasic acid anhydrides include, for example, phthalic anhydride, succinic anhydride, hetanoic anhydride, hymic anhydride, maleic anhydride, tetrahydrophthalic anhydride, hexahydraphthalic anhydride, tetraprom Phthalic anhydride, tetrachlorophthalic anhydride, trimellitic anhydride, pyromellitic anhydride, benzophenotetracarboxylic anhydride, 2,3,6,7 naphthalenetetracarboxylic dianhydride, 5- (2,5-oxotetrahydrofuryl) -3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride, styrene-maleic anhydride copolymer and the like. These polybasic acid anhydrides have the effect of improving the adhesiveness of the adhesive to the aluminum foil, and also include the aluminum foil and acetic acid, particularly when the interface between the aluminum foil and the adhesive is in contact with an organic acid containing acetic acid. It has the effect of inhibiting the formation of salts with organic acids.

  Examples of the phosphoric acids include phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, hypophosphoric acid, and the like, such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, and ultraphosphoric acid.

Examples of the phosphate esters include monomethyl orthophosphate, monoethyl orthophosphate, monopropyl orthophosphate, monobutyl orthophosphate, mono-2-ethylhexyl orthophosphate, monophenyl orthophosphate, monomethyl phosphite, monomethyl phosphite, and monoethyl phosphite. Monopropyl phosphite, monobutyl phosphite, mono-2-ethylhexyl phosphite, monophenyl phosphite, di-2-ethylhexyl orthophosphate, diphenyl orthophosphite, dimethyl phosphite, diethyl phosphite, dipropyl phosphite, Mono-, di-esterified products such as dibutyl phosphite, di-2-ethyl hexyl phosphite, di-phenyl phosphite, mono- and di-esterified products from condensed phosphoric acid and alcohols, for example, the above-mentioned phosphorus and acids, for example, ethylene oxide, Such as propylene oxide Those obtained by adding epoxy compounds, for example, be aliphatic or aromatic epoxy phosphate esters obtained by addition of the phosphorus acids diglycidyl ether and the like exemplified.

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

  These pigments, adhesion promoters and additives may be mixed with either one of the polyisocyanate component (A) and the polyol component (B), or may be used by mixing as a third component during coating. Can be. Among them, a premix in which a pigment, an adhesion promoter, and an additive are previously blended with a polyol component (B) is prepared as a polyol composition for a laminate adhesive of the present invention, and used as a two-component adhesive. However, it is preferable from the viewpoint of workability.

  The solvent-free type laminating adhesive of the present invention becomes the cured product of the present invention by being cured at a temperature of 20 ° C. to 60 ° C. after the adherends are bonded to each other, and its use should be specified. Although not a particular example, it is particularly useful as an adhesive when a substrate such as a plurality of films is laminated to form a laminate.

(Laminate)
The laminate of the present invention is obtained by applying the solventless laminating adhesive of the present invention to a first substrate, then laminating a second substrate on the application surface, and curing the adhesive layer.

Specifically, the solvent-free type laminating adhesive of the present invention is applied to a first substrate by, for example, a roll coater coating method, and then the second substrate is bonded without passing through a drying step. Method. The coating conditions are preferably about 300 to 3000 mPa · s at a viscosity of 40 ° C. in a heated state of 30 ° C. to 90 ° C. in a usual roll coater. Further, the coating amount is preferably 0.5 to 5 g / m ² , and more preferably about 0.5 to 3 g / m ² .

  Further, when the laminate of the present invention is used for package packaging, an adhesive may be applied on the printing surface of the plastic film on which the printing ink is printed as the base material. A good laminate appearance can be exhibited.

  When the solventless laminating adhesive of the present invention is used, after laminating, the adhesive hardens at room temperature or under heating for 6 to 24 hours, and exhibits practical physical properties.

  When the laminate is used as a packaging material, a flexible film such as a plastic film or a metal foil is used as the first base material or the second base material used in the present invention. Specifically, examples of the first substrate include a base film such as a PET (polyethylene terephthalate) film, a nylon film, an OPP (biaxially oriented polypropylene) film, various vapor-deposited films, an aluminum foil, and the like. Examples of the second substrate include sealant films such as CPP (unstretched polypropylene) film, VMCPP (aluminum-deposited unstretched polypropylene film), and LLDPE (linear low-density polyethylene) film.

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

  The laminated film thus obtained can be used industrially mainly as a packaging material for filling foods, detergents and drugs. Specific applications include detergents and chemicals such as laundry liquid detergents, kitchen liquid detergents, bath liquid detergents, bath liquid soaps, liquid shampoos, and liquid conditioners.

  The packaging material manufactured using the solventless laminating adhesive of the present invention not only has an excellent appearance, but also at the time of filling contents such as detergents and chemicals, after the lapse of time after filling, delamination and the like. It does not cause peeling of the laminate structure of Example 1 and has excellent adhesiveness and content resistance.

  Hereinafter, the contents and effects of the present invention will be described in more detail with reference to examples. In the examples, “parts” indicates “parts by mass”. The number average molecular weight (Mn) shown in each of Production Examples, Examples and Comparative Examples is a value measured by gel permeation chromatography (GPC) under the following conditions.

Production Example 1 [Synthesis of polyisocyanate (A-1)]
36 parts of 4,4-diphenylmethane diisocyanate and 19 parts of 2,4′-diphenylmethane diisocyanate were charged into a flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, and stirred under nitrogen gas at 60 ° C. Until heated. 11 parts of polypropylene glycol having a number average molecular weight of 400 (hereinafter abbreviated as “PPG”), 22 parts of PPG having a number average molecular weight of 1000, and 11 parts of PPG having a number average molecular weight of 2,000 were dropped in several portions. The mixture was stirred for 5 to 6 hours to complete the urethanization reaction. The NCO group content of the obtained polyisocyanate was 13.5%, and the viscosity was 1500 mPa.s. s. Hereinafter, this polyisocyanate is abbreviated as “A-1”.

Production Example 2 [Synthesis of polyisocyanate (A-2)]
60.7 parts of adipic acid, 28.2 parts of ethylene glycol, and 11.1 parts of diethylene glycol were placed in a polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a rectification tube, a water separator, and the like. The internal temperature was maintained at 220 ° C. by gradually heating the charged and rectifying tube so that the upper temperature did not exceed 100 ° C. When the acid value became 2.0 mgKOH / g or less, the esterification reaction was terminated to obtain a polyester polyol (referred to as “polyester polyol“ intermediate PE (i) ”).
30 parts of 4,4-diphenylmethane diisocyanate and 30 parts of 2,4′-diphenylmethane diisocyanate were charged into a reaction vessel in a flask equipped with a stirrer, a thermometer, and a nitrogen gas introduction tube, and stirred under nitrogen gas. Until heated. The intermediate PE (i) was added dropwise over several times, and the mixture was stirred for 5 to 6 hours to complete the urethanization reaction. The NCO group content of the obtained polyisocyanate was 14.0%, and the viscosity was 3000 mPa.s. s. Hereinafter, this polyisocyanate is abbreviated as “A-2”.

Production Example 3 (Synthesis of polyisocyanate (A-3))
55 parts of 4,4-diphenylmethane diisocyanate was charged into a reaction vessel in a flask equipped with a stirrer, a thermometer, and a nitrogen gas inlet tube, stirred under nitrogen gas, and heated to 60 ° C. 11 parts of PPG having a number average molecular weight of 400, 22 parts of PPG having a number average molecular weight of 1000, and 11 parts of PPG having a number average molecular weight of 2,000 were dropped in several portions, and the mixture was stirred for 5 to 6 hours to complete the urethanization reaction. Was. The NCO group content of the obtained polyisocyanate was 13.6%, and the viscosity was 2000 mPa.s. s. Hereinafter, this polyisocyanate is abbreviated as “A-3”.

Production Example 4 [Synthesis of polyisocyanate (A-4)]
60.0 parts of adipic acid and 56.0 parts of diethylene glycol were charged into a polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen gas inlet tube, a rectifying tube, a water separator, and the like. The internal temperature was maintained at 220 ° C. by gradually heating so as not to exceed 100 ° C. When the acid value became 2.0 mgKOH / g or less, the esterification reaction was terminated to obtain a polyester polyol (hereinafter, referred to as an obtained polyester polyol "intermediate PE (ii)").

  With respect to 180 parts by mass of the obtained “Intermediate PE (ii)”, 70 parts by mass of m-xylene diisocyanate and 100 parts by mass of a hexamethylene diisocyanate allophanate (“Basonat HA300” manufactured by BASF) were charged into a reaction vessel. The mixture was heated to 85 ° C. with stirring under a stream of nitrogen gas and reacted for about 10 hours to complete the urethanization reaction. The resulting polyisocyanate has an NCO group content of 10.0% and a viscosity of 3000 mPa.s. s. Hereinafter, this polyisocyanate is abbreviated as “A-4”.

Examples 1 to 13 and Comparative Examples 1 to 6
According to the formulation in the table, the polyisocyanate component (A) and the polyol component (B) were blended to obtain an adhesive of Example or Comparative Example. Various evaluations were performed using these.

(Curing speed: rise of adhesive properties)
Evaluation method: An adhesive prepared by blending a polyisocyanate component (A) and a polyol component (B) with a test laminator (manufactured by Tester Sangyo) so that the coating amount becomes 1.8 g / m ² in a plain biaxial manner. It was applied to a stretched nylon (“Emblem” manufactured by Unitika Ltd., 15 μm, hereinafter abbreviated as “ONy”) film. Thereafter, linear low-density polyethylene ("TUX-HC" manufactured by Tosello Co., Ltd., 60 μm; hereinafter, abbreviated as "LLDPE film") was laminated to prepare a laminate.
Next, the laminate was aged at 40 ° C., and the heat seal strength was measured after 3 hours and 6 hours, and the curability was evaluated according to the following criteria.
◎: 40 N / 15 mm or more ：: 20 N / 15 mm or more to less than 40 N / 15 mm ×: less than 20 N / 15 mm The sealing conditions were as follows: pressure: 0.1 MPa / cm ² , temperature: 180 ° C., sealing time: 1 second, The measurement conditions are seal strength: N / 15 mm, peeling speed: 300 mm / min, and measurement temperature: 25 ° C.

(Pot life)
About the adhesive which mix | blended the polyisocyanate component (A) and the polyol component (B), the viscosity after 30 minutes at 40 degreeC was measured. The change in viscosity immediately after blending and after 30 minutes was defined as the pot life, and evaluated according to the following criteria.
A: 3000 mPa. s: less than 3000 mPa.s. s or more to 5000 mPa.s. x: 5000 mPa.s. s or more

(Laminate appearance evaluation)
An adhesive prepared by blending the polyisocyanate component (A) and the polyol component (B) is coated in advance with a white printing ink (“Finart R794 White” manufactured by DIC) so that the applied amount is about 1.8 g / m ^{2 in} solid content. Was applied to a solid gravure-printed polyethylene terephthalate film (hereinafter abbreviated as “PET film”). Thereafter, an adhesive-coated surface of the film and an aluminum-deposited unstretched polypropylene (hereinafter abbreviated as “VMCPP film”) were laminated with a laminator to produce a laminated film. At this time, the laminating speed during lamination is 200 m / min.
Next, after the laminated film was aged at 40 ° C. for 1 day, the laminating appearance of the white printing ink portion of the 10 m portion outside the winding was evaluated according to the following criteria.
Using a scale loupe, the number of bubbles in a 1 cm ² scale was evaluated. ◎: 0 bubbles ○: 1 to 4 bubbles △: 5 to 16 bubbles ×: Number of bubbles: 17 or more

(Method of evaluating heat resistance)
An adhesive prepared by blending the polyisocyanate component (A) and the polyol component (B) is coated in advance with a white printing ink (“Finart R794 White” manufactured by DIC) so that the applied amount is about 1.8 g / m ^{2 in} solid content. Was coated with a test laminator (manufactured by Tester Sangyo) on a biaxially stretched nylon film (“Emblem” manufactured by Unitika Ltd., 15 μm; hereinafter abbreviated as “ONy”), which was gravure printed in a solid pattern. Next, an LLDPE film was laminated to produce a laminated film.
Next, the laminated film was aged at 40 ° C. for 3 days to cure the adhesive coating, thereby obtaining a two-layer composite film of ONy film / adhesive / LLDPE film.
A pouch having a size of 120 mm x 120 mm was prepared from the composite film after aging, and 70 g of a pseudo food in which vinegar, salad oil, and meat sauce were mixed at a mass ratio of 1: 1: 1 was filled. The prepared pouch was subjected to a boil sterilization treatment at 98 ° C. for 60 minutes, and the appearance of the white ink portion was visually evaluated according to the following criteria.
○: no change in appearance ×: delamination

  The results are shown in the table below.

The abbreviations in the table are as follows.
Actual: Example ratio: Comparative example GP-600: Sannics GP-600 (Sanyo Chemical Industries)
HD-402: Sannics HD-402 (Sanyo Chemical Industries)
HS-209: Sannics HD-209 (Sanyo Chemical Industries)
385SO: EXCENOL-385SO (AGC Asahi Glass)
PEG-2000: polyethylene glycol, molecular weight 2000
GP-3000: Sannics GP-3000 (Sanyo Chemical Industries)
GL-3000: Sannics GL-3000 (Sanyo Chemical Industries)
FA-702NS: Sannics FA-702NS (Sanyo Chemical Industries)
Castor oil: Kakukoichi (Ito Oil)
Castor oil derivative: URIC F-60 (Ito Oil)

  As a result, as the polyol component (B), a sugar alcohol or a sugar alcohol derivative (b1) having a number average molecular weight of 1,000 or less and four or more functional groups and a polyalkylene glycol having a number average molecular weight of 2,500 to 7,000 having a primary hydroxyl group are used. The non-solvent type laminating adhesive of the Example combining the above was able to achieve both a fast curing property (rapid rise in physical properties) and a stable pot life. In Example 8 in which castor oil was added, the laminate appearance was further improved.

Claims (7)

A solventless laminating adhesive comprising a polyisocyanate component (A) and a polyol component (B) as essential components,
The polyol component (B) is a polyol (b1), which is a sugar alcohol or sugar alcohol derivative having a number average molecular weight of 1,000 or less and having a functionality of 4 or more, and a polyalkylene having a number average molecular weight of 2,500 to 7,000 having a primary hydroxyl group. A non-solvent type laminating adhesive comprising glycol (b2). The said polyol component (B) contains the said polyol (b1) and the said polyalkylene glycol (b2) in the range of (b1) :( b2) = 10 / 90-60 / 40. Solvent type laminating adhesive. The usage ratio of the polyisocyanate component (A) and the polyol component (B) is such that the equivalent ratio of the isocyanate group in the polyisocyanate component (A) to the hydroxyl group in the polyol component (B) [isocyanate group / Hydroxyl group] in a ratio of 1.0 to 5.0. The solventless laminating adhesive according to any one of claims 1 to 3, wherein the polyol component (B) contains a castor oil or a castor oil derivative containing a hydroxyl group (b3). A cured product obtained by curing the solventless laminate adhesive according to claim 1. A laminate using the solventless laminating adhesive according to claim 1 for an adhesive layer. A package using the laminate according to claim 6.