JP2021095481A - Solvent-free adhesive composition and laminate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solvent-free adhesive composition in which an increase in viscosity after blending a main agent and a curing agent is suppressed, workability is excellent, and bending and floating resistance of a heat-sealed portion is excellent. Provided is a laminate having excellent bending floating resistance of a heat-sealed portion using the adhesive composition.
A two-component curable solvent-free adhesive composition containing a polyol component and a polyisocyanate component, wherein the polyol component is a polyester polyol having a primary hydroxyl group and a compound having an acid anhydride group. (A), and a polyol (B) having a secondary or tertiary hydroxyl group at the terminal and having a number average molecular weight of 1,000 or more and 10,000 or less, said reaction product (A). A solvent-free adhesive composition having a content of 10 to 60% by mass based on the total mass of the polyol component.
[Selection diagram] None

Description

INDUSTRIAL APPLICABILITY The present invention has an excellent adhesive function, which is suitably used when a plurality of various plastic films and metal-deposited films are laminated to produce a laminate for packaging of foods, pharmaceuticals, cosmetics, detergents, miscellaneous goods, etc. The present invention relates to a solvent-based adhesive composition. Furthermore, the present invention relates to a laminate used for packaging foods, pharmaceuticals, cosmetics, detergents, miscellaneous goods and the like.

In recent years, as a packaging material for foods, pharmaceuticals, cosmetics, detergents, miscellaneous goods, etc., a metal foil such as aluminum foil or a metal-deposited film and a plastic film such as polyethylene, polypropylene, vinyl chloride, polyester, nylon, etc. have been laminated and composited. The thing is used. As an adhesive for adhering these plastic films to a metal foil or a metal vapor-deposited film, those composed of a polyol obtained by reacting an aromatic polyvalent carboxylic acid anhydride and an organic isocyanate compound are known.

Further, conventionally, as a solvent type laminate adhesive used for a laminated composite film containing such a metal foil or a metal vapor deposition film, a two-component curable adhesive containing a polyol compound as a main agent and a polyisocyanate compound as a curing agent. Is preferably used, and for the purpose of imparting adhesion to a metal foil or a metal vapor deposition film, an acid group is introduced into the molecular terminal of a polyol compound (for example, Patent Document 1), and phosphoric acid and silane are used as additives. A method of using a coupling agent in combination is widely known.

On the other hand, in recent years, there has been an increasing demand for solvent-free adhesives due to the tightening of laws and regulations and consideration for environmental protection or safety, and there is no laminate adhesive used for bonding between metal foils and various plastic films. Solventification is being considered.

However, the solvent-free adhesive has a significantly faster curing reaction rate than the solvent-based adhesive. Therefore, for example, when an acid group is introduced into the main agent for the purpose of improving adhesion to a metal vapor deposition film, the acid group is introduced. Due to the urethanization catalytic effect of the above, curing is further promoted, and the viscosity increases sharply after the main agent and the curing agent are mixed, causing a problem that workability deteriorates.

In response to the above problems, Patent Document 1 improves workability by limiting the terminal hydroxyl groups of the acid-modified polyol with acid anhydride to secondary and tertiary, and suppressing the reactivity due to the influence of steric hindrance. A two-component curable solvent-free adhesive composition that has been prepared is described.

Japanese Unexamined Patent Publication No. 2005-89734

However, the laminate using the adhesive composition described in Patent Document 1 has a problem that floating occurs when the heat-sealed portion is bent because the metal adhesion and heat resistance are low.
Therefore, an object of the present invention is to provide a solvent-free adhesive composition which is excellent in workability and excellent in bending and floating resistance of a heat-sealed portion because an increase in viscosity after blending a main agent and a curing agent is suppressed. There is. Another object of the present invention is to provide a laminate having excellent bending and floating resistance of a heat-sealed portion using the adhesive composition.

As a result of diligent studies to solve the above problems, it was found that the above problems can be solved by the following embodiments, and the present invention has been completed.

An embodiment of the present invention is a two-component curable solvent-free adhesive composition containing a polyol component and a polyisocyanate component.
The polyol component has a reaction product (A) of a polyester polyol having a primary hydroxyl group and a compound having an acid anhydride group, and a secondary or tertiary hydroxyl group at the terminal, and has a number average molecular weight of 1,. Contains 000 or more and 10,000 or less polyol (B)
The present invention relates to a solvent-free adhesive composition in which the content of the reaction product (A) is 10 to 60% by mass with respect to the total mass of the polyol component.

Another embodiment of the present invention relates to the solvent-free adhesive composition, wherein the polyvalent carboxylic acid constituting the polyester polyol having a primary hydroxyl group contains adipic acid and an aromatic dicarboxylic acid.

Another embodiment of the present invention relates to the solvent-free adhesive composition in which the content of the aromatic dicarboxylic acid is 25 to 40% by mass with respect to the total mass of the polyester polyol having a primary hydroxyl group. ..

Another embodiment of the present invention relates to the solvent-free adhesive composition, wherein the polyisocyanate component contains an aromatic polyisocyanate or a derivative thereof.

Another embodiment of the present invention relates to the solvent-free adhesive composition in which the content of the reaction product (A) is 25 to 45% by mass with respect to the total mass of the polyol component.

Another embodiment of the present invention relates to a laminate in which an adhesive layer made of the solvent-free adhesive composition is laminated between at least two sheet-like substrates.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a solvent-free adhesive composition which is excellent in workability and excellent in bending and floating resistance of a heat-sealed portion because an increase in viscosity after blending a main agent and a curing agent is suppressed. Further, according to the present invention, it is possible to provide a laminate having excellent bending and floating resistance of a heat-sealed portion using the adhesive composition.

[Solvent-free adhesive composition]
The solvent-free adhesive composition of the present invention has a reaction product (A) of a polyester polyol having a primary hydroxyl group and a compound having an acid anhydride group, and a secondary or tertiary hydroxyl group at the terminal. A polyol component containing a polyol (B) having a number average molecular weight of 1,000 or more and 10,000 or less and a polyisocyanate component are contained, and the content of the reaction product (A) is based on the total amount of the polyol component. It is characterized by being 10 to 60% by mass.
The reaction product (A) of the polyester polyol having a primary hydroxyl group and the compound having an acid anhydride group has an acid value and improves the affinity with the surface of the substrate. Further, the reaction product (A) and the polyol (B) having a secondary or tertiary hydroxyl group at the terminal have different reactivity with the polyisocyanate component due to steric hindrance. Specifically, the polyisocyanate component reacts preferentially with the reaction product (A), and the reaction with the polyol (B) having a large steric hindrance proceeds with a delay.
Therefore, the adhesive composition of the present invention can provide a polyurethane resin in which segments having different hardness are unevenly distributed after curing, and the laminate using the adhesive suppresses the occurrence of floating due to bending of the heat-sealed portion. can do.
Further, by containing the polyol (B) having a large steric hindrance and a relatively slow reaction rate, the increase in viscosity after mixing and blending the polyol component and the polyisocyanate component is suppressed, and the effect of prolonging the pot life is exhibited. ..
As a result, the laminate using the solvent-free adhesive composition of the present invention can be used as a packaging material in various uses such as foods, pharmaceuticals, cosmetics, detergents, and miscellaneous goods.
Hereinafter, the present invention will be described in detail.

[Polyol component]
The polyol component used in the present invention is a reaction product (A) of a polyester polyol having a primary hydroxyl group and a compound having an acid anhydride group, and a polyol (B) having a secondary or tertiary hydroxyl group at the terminal. including.

[Reaction product (A)]
The polyester polyol having a primary hydroxyl group used in the reaction product (A) is not particularly limited as long as it is a known polyester polyol having a primary hydroxyl group, and can be selected from conventionally known polyester polyols, either alone or in two kinds. The above can be mixed and used.

(Polyester polyol having a primary hydroxyl group)
The polyester polyol having a primary hydroxyl group is, for example, a polyester polyol obtained by reacting a polyvalent carboxylic acid or a dialkyl ester thereof or a mixture thereof with a polyhydric alcohol having a primary hydroxyl group at both ends; caprolactone. , Polyvalerolactone, or polyester polyol obtained by ring-opening polymerization of lactones such as poly (β-methyl-γ-valerolactone); These may be used alone or in combination of two or more.
Above all, from the viewpoint of reactivity, the polyester polyol preferably contains a polyester polyol obtained by reacting a polyvalent carboxylic acid with a glycol having a primary hydroxyl group at both ends.

Examples of the polyvalent carboxylic acid include acyclic aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecandicarboxylic acid, maleic anhydride, and fumaric acid; 1,3-cyclopentanedicarboxylic acid. , An alicyclic dicarboxylic acid such as 1,4-cyclohexanedicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, Aromatic dicarboxylic acids such as naphthalic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p'-dicarboxylic acid; anhydrides or ester-forming derivatives of these aliphatic or aromatic dicarboxylic acids; p Examples thereof include −hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid and ester-forming derivatives of these dihydroxycarboxylic acids, and polybasic acids such as dimer acid.
Among them, from the viewpoint of reactivity, the polyvalent carboxylic acid preferably contains acyclic aliphatic dicarboxylic acid and aromatic dicarboxylic acid, more preferably adipic acid and aromatic dicarboxylic acid, and further preferably adipic acid. And isophthalic acid.

The content of the aromatic dicarboxylic acid is preferably 25 to 40% by mass with respect to the total mass of the polyester polyol having a primary hydroxyl group. When it is 25% by mass or more, it is more preferable because it has excellent heat resistance and follows the heat of the heat seal treatment and further suppresses floating. When it is 40% by mass or less, the rigidity due to the aromatic skeleton does not become too high, and it is more preferable because it follows the elongation of the bent base material and further suppresses the floating.

Examples of the polyhydric alcohol having a primary hydroxyl group at both ends include a diol and a trifunctional or higher functional polyol.
Examples of the diol include ethylene glycol, diethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl1,5-pentanediol, neopentyl glycol, and 1,6. -Hexanediol, 3,3'-dimethylol heptane, aliphatic diols such as 1,4-bis (hydroxymethyl) cyclohesan; ether glycols such as polytetramethylene ether glycol and polyoxyethylene glycol; said aliphatic diols. And modified polyether diols obtained by ring-opening polymerization with various cyclic ether bond-containing compounds such as ethylene oxide and tetrahydrofuran; polycondensation of the aliphatic diol with various lactones such as lactanoids and ε-caprolactone. Examples thereof include a lactone-based polyester polyol obtained by the reaction; an alkylene oxide adduct of bisphenol obtained by adding ethylene oxide or the like to bisphenol such as bisphenol A and bisphenol F.

Examples of the trifunctional or higher functional polyol include aliphatic polyols such as trimethylolethane, trimethylolpropane, glycerin, hexanetriol and pentaerythritol; the aliphatic polyol and ethylene oxide, propylene oxide, tetrahydrofuran and ethylglycidyl ether. Modified polyether polyols obtained by ring-open polymerization with various cyclic ether bond-containing compounds such as propyl glycidyl ethers, butyl glycidyl ethers, phenyl glycidyl ethers, allyl glycidyl ethers; said aliphatic polyols and such as ε-caprolactone. Examples thereof include lactone-based polyester polyols obtained by polycondensation reaction with various lactones.

Among them, from the viewpoint of reactivity, the polyhydric alcohol preferably contains an aliphatic diol, and more preferably contains ethylene glycol or diethylene glycol.

(Compound having an acid anhydride group)
Examples of the compound having an acid anhydride group include phthalic anhydride, trimellitic anhydride, and trimellitic acid ester anhydride, and trimellitic anhydride is preferable.
The amount of the compound having an acid anhydride group used in obtaining the reaction product (A) is preferably 0.2 to 1.0 part by mass, based on 100 parts by mass of the polyester polyol having a primary hydroxyl group. It is preferably 0.4 to 0.7 parts by mass. When it is 0.4 parts by mass or more, the affinity between the reaction product (A) and the surface of the base material is improved, and excellent bending and floating resistance of the heat-sealed portion is exhibited, which is more preferable. When it is 0.7 parts by mass or less, the acid value of the reaction product (A) does not become too high and the pot life is excellent, which is more preferable.

The acid value of the reaction product (A) is preferably 1 to 20 mgKOH / g, more preferably 2 to 10 mgKOH / g, and even more preferably 3 to 8 mgKOH / g. When the acid value is 3 mgKOH / g or more, the affinity between the reaction product (A) and the surface of the base material is improved, and excellent bending and floating resistance of the heat-sealed portion is exhibited, which is more preferable. When it is 8 mgKOH / g or less, it is more preferable because the pot life of the reaction product (A) is excellent.

The hydroxyl value of the reaction product (A) is preferably 30 to 80 mgKOH / g, more preferably 40 to 60 mgKOH / g.

The number average molecular weight of the reaction product (A) is preferably 1,000 to 10,000, more preferably 1,500 to 5,000. When the number average molecular weight is 1,000 or more, the cohesive force of the resin is increased and excellent adhesive strength is exhibited, which is preferable. When the number average molecular weight is 10,000 or less, the viscosity increase after mixing with the curing agent becomes gradual, and the coatability does not deteriorate, which is preferable.

[Polyol (B) having a secondary or tertiary hydroxyl group at the end]
From the viewpoint of pot life, the solvent-free adhesive composition of the present invention contains a polyol (B) having a secondary or tertiary hydroxyl group at the terminal and having a number average molecular weight of 1,000 or more and 10,000 or less. .. The polyol (B) has a secondary or tertiary hydroxyl group at the terminal, and is not particularly limited as long as the number average molecular weight is 1,000 or more and 10,000 or less. For example, a polyester polyol, a polyether polyol, and the like. Examples thereof include polyether ester polyols, polyesteramide polyols, acrylic polyols, polycarbonate polyols, polyhydroxyalkanes, polyurethane polyols, castor oil or mixtures thereof. These may be used alone or in combination of two or more. Among them, polyester polyols are preferably contained from the viewpoint that the adhesive performance does not easily deteriorate with time.

Examples of the polyester polyol having a secondary or tertiary hydroxyl group at the terminal include a polyvalent carboxylic acid or a dialkyl ester thereof or a mixture thereof, and a polyhydric alcohol having a secondary or tertiary hydroxyl group at at least one terminal. Examples thereof include polyester polyols obtained by reacting with a polyhydric alcohol containing.
Examples of the polyvalent carboxylic acid include the same polyvalent carboxylic acids used in the production of the polyester polyol having a primary hydroxyl group as described above.
Among them, from the viewpoint of reactivity, the polyvalent carboxylic acid preferably contains a non-cyclic aliphatic dicarboxylic acid.

Examples of the polyhydric alcohol having a secondary or tertiary hydroxyl group at at least one end include glycol having a secondary or tertiary hydroxyl group at at least one end.
Glycols having a secondary hydroxyl group include propylene glycol, 1,3-butylene glycol, 2,2,4-trimethyl-1,3-pentanediol, 2,4-pentanediol, 2,5-hexanediol, and 1, , 2,6-Hexanetriol and the like.
Examples of the glycol having a tertiary hydroxyl group include 3-methyl-1,3-butylene glycol, 2,5-dimethyl-2,5-hexanediol and the like.

The polyhydric alcohol constituting the polyester polyol having a secondary or tertiary hydroxyl group at the terminal has a primary hydroxyl group at both ends in addition to the above-mentioned polyhydric alcohol having a secondary or tertiary hydroxyl group at at least one terminal. It may contain a polyhydric alcohol having. Further, a polyhydric alcohol having a secondary or tertiary hydroxyl group at at least one end may have a primary hydroxyl group.
Even if the polyhydric alcohol has a primary hydroxyl group, the primary hydroxyl group having a high reaction rate reacts preferentially with the above-mentioned polyvalent carboxylic acid, so that the secondary or tertiary hydroxyl group remains. Polyester polyol can be obtained.

The polyester polyol having a secondary or tertiary hydroxyl group at the terminal preferably has a secondary hydroxyl group at the terminal from the viewpoint of aging time and curability. When the terminal is a secondary hydroxyl group, the reaction rate does not become slower than necessary, the aging time is within an appropriate range, and curing failure is less likely to occur, which is preferable.

The polyester polyol having a secondary or tertiary hydroxyl group at the terminal may be acid-modified with a compound having an acid anhydride group. As the compound having an acid anhydride group, the compound having an acid anhydride group in the above-mentioned reaction product (A) can be incorporated.

The number average molecular weight of the polyester polyol having a secondary or tertiary hydroxyl group at the terminal is 1,000 to 10,000, preferably 3,000 to 7,000, and more preferably 4,000 to 6,. It is 000. When the number average molecular weight is 1,000 or more, the cohesive force of the polyol increases and excellent adhesive strength is exhibited, which is more preferable. When the number average molecular weight is 10,000 or less, the increase in viscosity after mixing with the curing agent becomes gradual, and the coatability does not deteriorate, which is more preferable.

The acid value of the polyester polyol having a secondary or tertiary hydroxyl group at the terminal is not particularly limited, but is preferably 0 to 20 mgKOH / g, more preferably 0 to 10 mgKOH / g. The hydroxyl value of the polyester polyol having a secondary or tertiary hydroxyl group at the terminal is not particularly limited, but is preferably 50 to 250 mgKOH / g, more preferably 80 to 220 mgKOH / g, and further preferably 100 to 200 mgKOH / g. ..

[Other polyols]
The polyol component may contain a polyol other than the above-mentioned (A) and (B). In particular, from the viewpoint of coatability, it is preferable to contain a low-viscosity polyol as a diluent, and more preferably, it contains at least one selected from the group consisting of methylpropanediol and a low molecular weight polyether polyol.

[Polyisocyanate component]
The solvent-free adhesive composition of the present invention contains a polyisocyanate component. Examples of the polyisocyanate component include aromatic polyisocyanates and aliphatic polyisocyanates, and aromatic polyisocyanates or derivatives thereof are preferably used. These polyisocyanate components can be used alone or in combination of two or more.

Examples of the aromatic polyisocyanate include m-phenylene diisocyanate, p-phenylenedi isocyanate, 4,4'-diphenyldiisocyanate, 1,5-naphthalenediisocyanate, 2,4-tolylene diisocyanate or 2,6-tolylene diisocyanate or 2,6-tolylene diisocyanate. The mixture, 4,4'-toluene diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate or a mixture thereof, ω, ω'-diisocyanate-1,4-diethylbenzene, 1,3-bis (1-isocyanate-1-methylethyl) benzene or 1,4-bis (1-isocyanate-1-methylethyl) benzene or a mixture thereof Aromatic diisocyanates such as triphenylmethane-4,4', 4''-triisocyanates, 1,3,5-triisocyanatebenzene, 2,4,6-triisocyanates Aromatic triisocyanates such as toluene; 4 , 4'-Diphenyldimethylmethane-2, 2'-5,5'-aromatic polyisocyanates such as tetraisocyanates;

Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, and 2 , 4,4-trimethylhexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methylcaproate, 1,3-xylylene diisocyanate or 1,4-xylylene diisocyanate.

The polyisocyanate component may be a derivative derived from the above-mentioned aromatic or aliphatic polyisocyanate. Examples of the derivative include a reaction product of an aromatic or aliphatic polyisocyanate and a known polyol.
Known polyols include, for example, ethylene glycol, propylene glycol, butylene glycol, hexylene glycol, neopentyl glycol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 3,3'-dimethylol. Low molecular weight polyols with a molecular weight of less than 200, such as propane, cyclohexanedimethanol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol; polypropylene glycol, polyester polyols, polyether ester polyols, polyesteramides. Polyols, polycaprolactone polyols, polyvalerolactone polyols, acrylic polyols, polycarbonate polyols, polyhydroxyalkanes, castor oil, polyols such as polyurethane polyols; may be used alone or in combination of two or more. Good.
The molar ratio of isocyanate groups to hydroxyl groups (NCO molar number / OH molar number) at the time of reaction between an aromatic or aliphatic polyisocyanate and a known polyol is preferably 2 or more.

The polyisocyanate component is preferably a reaction product of polyisocyanate and polypropylene glycol, and more preferably a reaction product of aromatic polyisocyanate and polypropylene glycol. It is preferable that the polyisocyanate component contains an aromatic skeleton because the heat resistance is improved and the occurrence of floating due to bending of the heat seal portion can be suppressed.
The number average molecular weight of polypropylene glycol is preferably 200 to 3,000.

[Manufacturing of adhesive composition]
The solvent-free adhesive composition of the present invention requires a polyol component containing the above-mentioned reaction products (A) and polyol (B) and a polyisocyanate component, and if necessary, contains a diluent. It can be produced by weighing the above components and stirring well with a spatula or the like. The molar ratio of isocyanate groups to hydroxyl groups (number of moles of NCO / number of moles of OH) in all the components of the adhesive composition is preferably 0.8 to 2.0, more preferably 1.0 to 1.5. Is.

The content of the reaction product (A) is 10 to 60% by mass, more preferably 15 to 55% by mass, and particularly preferably 25 to 45% by mass, based on the total amount of the polyol component. When it is 10% by mass or more, the occurrence of floating due to the bending of the heat-sealed portion can be suppressed, and when it is 60% by mass or less, the increase in viscosity after mixing and blending the polyol component and the polyisocyanate component is suppressed and the pot is used. You can extend your life. Further, when it is 25% by mass or more, it is preferable because the floating due to the bending of the heat seal portion can be particularly suppressed, and when it is 45% by mass or less, the pot life can be further extended, which is preferable.

From the viewpoint of adhesive performance, the content of the polyisocyanate component is preferably 40 to 120 parts by mass, and more preferably 70 to 90 parts by mass with respect to 100 parts by mass of the total polyol component.

The viscosity of the solvent-free adhesive composition is 100 to 10,000 mPa · s, more preferably 1,000 to 5,000 mPa · s at room temperature (25 ° C.) to 120 ° C., preferably room temperature to 80 ° C. .. When it is 100 mPa · s or more, the initial cohesive force of the adhesive is excellent. When it is 10,000 mPa · s or less, the coating appearance is excellent.

(Silane coupling agent)
The adhesive composition may contain a silane coupling agent from the viewpoint of improving the adhesive strength to a metal-based material such as a metal foil. Examples of the silane coupling agent include trialkoxysilanes having a vinyl group such as vinyltriethoxysilane and vinyltriethoxysilane; 3-aminopropyltriethoxysilane and N- (2-aminoethyl) -3-aminopropyltri. Trialkoxysilane having an amino group such as methoxysilane; glycidyl such as 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) -ethyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane Trialkoxysilanes having a group; These can be used alone or in any combination of two or more.
The content of the silane coupling agent is preferably 0.1 to 5 parts by mass, and more preferably 0.2 to 3 parts by mass with respect to 100 parts by mass of the total polyol component. Within the above range, the adhesive strength to the metal foil can be improved.

(Phosphoric acid or phosphoric acid derivative)
The adhesive composition may contain phosphoric acid or a phosphoric acid derivative from the viewpoint of improving the adhesive strength to a metal-based material such as a metal foil, and two or more kinds may be used in combination.
The phosphoric acid may be any phosphoric acid having at least one free oxygen acid, for example, phosphoric acids such as hypophosphoric acid, phosphoric acid, orthophosphoric acid, and hypophosphoric acid; metaphosphoric acid, Condensed phosphoric acids such as pyrophosphoric acid, tripolyphosphoric acid, polyphosphoric acid, ultraphosphoric acid; Examples of the phosphoric acid derivative include those obtained by partially esterifying the above-mentioned phosphoric acid with alcohols while leaving at least one free oxygen acid. Examples of the alcohols include aliphatic alcohols such as methanol, ethanol, ethylene glycol and glycerin; aromatic alcohols such as phenol, xylenol, hydroquinone, catechol and fluoroglycinol.
The content of phosphoric acid or a derivative thereof is preferably 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and particularly preferably 0.05 to 50% by mass, based on the total solid content of the adhesive composition. It is 1% by mass.

(Other additives)
The adhesive composition may contain various additives as long as the effects of the present invention are not impaired. Examples of the additive include inorganic fillers such as silica, alumina, mica, talc, aluminum flakes, and glass flakes, layered inorganic compounds, stabilizers (antioxidants, heat stabilizers, ultraviolet absorbers, hydrolysis inhibitors, etc.). ), Anticorrosives, thickeners, plasticizers, antistatic agents, lubricants, antiblocking agents, colorants, fillers, crystal nucleating agents, catalysts for adjusting the curing reaction.

[Laminated body]
The laminate of the present invention is obtained by laminating an adhesive layer made of the above-mentioned solvent-free adhesive composition between at least two sheet-like substrates, and specifically, a solvent-free adhesive composition. An object is applied to a first sheet-like base material to form an adhesive layer, a second sheet-like base material is superposed on the adhesive layer, and the adhesive layer is located between both sheet-like base materials. Is cured.
The sheet-shaped base material is not particularly limited, and examples thereof include conventionally known plastic films, papers, metal foils, and the like, and the two sheet-shaped base materials may be of the same type or different types.
As the plastic film, a film of a thermoplastic resin or a thermosetting resin can be used, and a film of a thermoplastic resin is preferable. Examples of the thermoplastic resin include polyolefins, polyesters, polyamides, polystyrenes, vinyl chloride resins, vinyl acetate resins, ABS resins, acrylic resins, acetal resins, polycarbonate resins, and fibrous plastics. The sheet-like base material may include a barrier film such as a thin-film deposition layer, and examples of the vapor-deposited layer include a thin-film deposition layer of aluminum, silica, alumina, or the like.

The first sheet-like base material is preferably a plastic film. Examples of the plastic film include those generally used for packaging materials, and polyester resin films such as polyethylene terephthalate (hereinafter, PET), polyethylene naphthalate (hereinafter, PEN), and polylactic acid (hereinafter, PLA); Polyethylene resin film such as polyethylene (hereinafter PE), polypropylene (hereinafter PP); polystyrene resin film; nylon 6, poly-p-xylylene adipamide (hereinafter MXD6 nylon) and other polyamide resin film; polycarbonate Resin film; polyacrylic nitrile resin film; polyimide resin film; these multilayer bodies (for example, nylon 6 / MXD6 / nylon 6, nylon 6 / ethylene-vinyl alcohol copolymer / nylon 6) and mixtures thereof can be mentioned. .. Among them, those having mechanical strength and dimensional stability are preferable.
The plastic film preferably has a thickness of 5 μm or more and 50 μm or less, and more preferably 10 μm or more and 30 μm or less.

When the second sheet-like base material is the outermost layer of the laminate, the second sheet-like base material is preferably a sealant base material.
Examples of the sealant base material include polyethylene such as low-density polyethylene (hereinafter, LDPE), linear low-density polyethylene (hereinafter, LLDPE) and high-density polyethylene (hereinafter, HDPE), acid-modified polyethylene, polypropylene, and acid-modified polypropylene. , Copolymerized polypropylene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylic acid ester copolymer, ethylene- (meth) acrylic acid copolymer, ionomer.
The thickness of the sealant base material is not particularly limited, and is preferably 10 to 150 μm, more preferably 20 to 70 μm, in consideration of processability to the packaging material, heat sealability, and the like. Further, by providing the sealant base material with irregularities having a height difference of about several μm, slipperiness and tearability of the packaging material can be imparted.
When the second sheet-like base material serves as an intermediate layer of the laminated body, the above-mentioned plastic film, paper, metal foil, or the like can be preferably used as the second sheet-like base material.

The sheet-like base material may have a printing layer on the base material.
The printing layer is used for decoration, display of contents, display of expiration date, display of manufacturers, sellers, etc., and for display of other things and giving aesthetics, such as letters, numbers, patterns, figures, symbols, patterns, etc. A layer that forms any desired print pattern, including a solid print layer. The print layer can be formed by using a conventionally known pigment or dye, and the method for forming the print layer is not particularly limited.
Generally, the printing layer is formed by using a printing ink containing a colorant such as a pigment or a dye. The method of applying the printing ink is not particularly limited, and the printing ink can be applied by a method such as a gravure coating method, a flexographic coating method, a roll coating method, a bar coating method, a die coating method, a curtain coating method, a spin coating method, or an inkjet method. .. The printed layer can be formed by leaving it as it is or, if necessary, by blowing air, heating, drying under reduced pressure, or irradiating with ultraviolet rays.
The printed layer preferably has a thickness of 0.1 μm or more and 10 μm or less, more preferably 1 μm or more and 5 μm or less, and further preferably 1 μm or more and 3 μm or less.

Examples of the method for producing the laminate include conventionally known methods. For example, an adhesive is applied to one side of one sheet-like base material using a laminator to form an uncured adhesive layer, and then applied. Examples thereof include a method of bonding the surface and the other sheet-like substrate, and then curing the adhesive layer at room temperature or heating. The amount of the adhesive composition applied after drying is preferably ^{about 1 to 4 g / m 2} , and the thickness of the laminate is preferably 10 μm or more.

An example of the structure of the laminated body of the present invention is given below, but the present invention is not limited thereto.
Biaxially stretched polypropylene (hereinafter, OPP) / printing layer / adhesive layer / unstretched polypropylene (hereinafter, CPP),
OPP / printing layer / adhesive layer / AL vapor deposition CPP,
OPP / printing layer / adhesive layer / PE,
Print layer / OPP / Adhesive layer / CPP,
NY / printing layer / adhesive layer / PE,
Print layer / NY / Adhesive layer / CPP
NY / printing layer / adhesive layer / CPP,
PET / printing layer / adhesive layer / CPP,
Print layer / PET / Adhesive layer / CPP
PET / printing layer / adhesive layer / NY / adhesive layer / CPP,
Transparent vapor deposition PET / printing layer / adhesive layer / NY / adhesive layer / CPP,
PET / printing layer / adhesive layer / AL vapor deposition PET / adhesive layer / PE,
PET / printing layer / adhesive layer / AL / adhesive layer / CPP,
PET / printing layer / adhesive layer / AL / adhesive layer / PE,
PET / printing layer / adhesive layer / NY / adhesive layer / AL / adhesive layer / CPP,
PET / printing layer / adhesive layer / AL / adhesive layer / NY / adhesive layer / CPP

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples. “Parts” and “%” in Examples and Comparative Examples mean “parts by mass” and “% by mass” unless otherwise specified.

[Measurement method of number average molecular weight (Mn)]
The number average molecular weight (Mn) was measured using GPC (gel permeation chromatography) "Shodex GPC System-21" manufactured by Showa Denko KK. GPC is a liquid chromatography in which a substance dissolved in a solvent is separated and quantified by the difference in its molecular size. The solvent is tetrohydrofuran, and the molecular weight is determined in terms of polystyrene.

[Measurement method of acid value (AV)]
Approximately 1 g of the sample was precisely weighed into a stoppered Erlenmeyer flask, and 100 mL of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution was added and dissolved. Phenolphthalein test solution was added to this as an indicator and lasted for 30 seconds. Then, it was titrated with 0.1N alcoholic potassium hydroxide solution until the solution became pink. The acid value was determined by the following (Equation 1). (Unit: mgKOH / g).
(Equation 1) Acid value (mgKOH / g) = [{(ba) × F × 28.25} / S]
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (mL)
b: Consumption (mL) of 0.1N alcoholic potassium hydroxide solution in the blank experiment
F: Titer of 0.1N alcoholic potassium hydroxide solution

[Measurement method of hydroxyl value (OHV)]
Approximately 1 g of the sample was precisely weighed into a stoppered Erlenmeyer flask, and 100 mL of a toluene / ethanol (volume ratio: toluene / ethanol = 2/1) mixed solution was added and dissolved. Further, exactly 5 mL of an acetylating agent (a solution in which 25 g of acetic anhydride was dissolved in pyridine to make a volume of 100 mL) was added, and the mixture was stirred for about 1 hour. Phenolphthalein TS is added as an indicator to this and lasts for 30 seconds. Then, it was titrated with 0.1N alcoholic potassium hydroxide solution until the solution became pink. The hydroxyl value was determined by the following (Equation 2). The hydroxyl value was taken as the value of the dry state of the resin (unit: mgKOH / g).
(Equation 2) Hydroxy group value (mgKOH / g) = [{(ba) × F × 28.25} / S] / (nonvolatile content concentration / 100) + D
S: Sample collection amount (g)
a: Consumption of 0.1N alcoholic potassium hydroxide solution (mL)
b: Consumption (mL) of 0.1N alcoholic potassium hydroxide solution in the blank experiment
F: Titer of 0.1N alcoholic potassium hydroxide solution D: Acid value (mgKOH / g)

[Measurement method of NCO content (mass%)]
About 1 g of the sample was weighed in a 200 mL Erlenmeyer flask, and 10 mL of a toluene solution of 0.5 N-n-butylamine and 10 mL of toluene were added and dissolved. Next, a phenolphthalein test solution was added as an indicator, held for 30 seconds, and then titrated with a 0.25N hydrochloric acid solution until the solution turned pink. The NCO content (mass%) was determined by the following (Equation 3).
(Equation 3): NCO (mass%) = {(ba) × 4.202 × F × 0.25} / S
However, S: sample collection amount (g)
a: Consumption of 0.25N hydrochloric acid solution (ml)
b: Consumption of 0.25N hydrochloric acid solution in blank experiment (ml)
F: Titer of 0.25N hydrochloric acid solution

[Synthesis of reaction product (A)]
(Synthesis Example 1) Reaction product (A-1)
40 parts of ethylene glycol, 240 parts of diethylene glycol, 200 parts of isophthalic acid, and 200 parts of adipic acid are charged in a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe, and stirred under a nitrogen stream. While doing so, the temperature was raised to 260 ° C. After continuing the reaction until the acid value becomes 5 or less, the pressure is gradually reduced, the reaction is continued at 1 mmHg, excess alcohol is removed, and the polyester has a primary hydroxyl group at the terminal and no secondary hydroxyl group. A polyol was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.5 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 5.0 mgKOH / g, a hydroxyl value of 53 mgKOH / g, and a number average molecular weight of 2,000 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. The reaction product (A-1) of and trimellitic anhydride was obtained.

(Synthesis Example 2) Reaction product (A-2)
Similar to the reaction product (A-1), a polyester polyol having a primary hydroxyl group at the terminal and no secondary hydroxyl group was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.3 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 3.8 mgKOH / g, a hydroxyl value of 54 mgKOH / g, and a number average molecular weight of about 2,000 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. A reaction product (A-2) of and trimellitic anhydride was obtained.

(Synthesis Example 3) Reaction product (A-3)
Similar to the reaction product (A-1), a polyester polyol having a primary hydroxyl group at the terminal and no secondary hydroxyl group was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.8 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 7.2 mgKOH / g, a hydroxyl value of 51 mgKOH / g, and a number average molecular weight of about 2,000 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. A reaction product (A-3) of and trimellitic anhydride was obtained.

(Synthesis Example 4) Reaction product (A-4)
50 parts of ethylene glycol, 150 parts of diethylene glycol, 80 parts of 1,4-butanediol, 140 parts of isophthalic acid, 260 parts of adipic acid in a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe. The temperature was raised to 260 ° C. while stirring under a nitrogen stream. After continuing the reaction until the acid value becomes 5 or less, the pressure is gradually reduced, the reaction is continued at 1 mmHg, excess alcohol is removed, and the polyester has a primary hydroxyl group at the terminal and no secondary hydroxyl group. A polyol was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.5 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 5.1 mgKOH / g, a hydroxyl value of 58 mgKOH / g, and a number average molecular weight of about 1,800 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. A reaction product (A-4) of and trimellitic anhydride was obtained.

(Synthesis Example 5) Reaction product (A-5)
60 parts of ethylene glycol, 140 parts of diethylene glycol, 100 parts of 1,4-butanediol, 180 parts of terephthalic acid, 250 parts of adipic acid in a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe. The temperature was raised to 260 ° C. while stirring under a nitrogen stream. After continuing the reaction until the acid value becomes 5 or less, the pressure is gradually reduced, the reaction is continued at 1 mmHg, excess alcohol is removed, and the polyester has a primary hydroxyl group at the terminal and no secondary hydroxyl group. A polyol was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.5 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 5.1 mgKOH / g, a hydroxyl value of 56 mgKOH / g, and a number average molecular weight of about 1,900 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. A reaction product (A-5) of and trimellitic anhydride was obtained.

(Synthesis Example 6) Reaction product (A-6)
50 parts of ethylene glycol, 100 parts of diethylene glycol, 100 parts of 1,4-butanediol, 110 parts of isophthalic acid, 140 parts of terephthalic acid in a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe. A part and 120 parts of adipic acid were charged, and the temperature was raised to 260 ° C. while stirring under a nitrogen stream. After continuing the reaction until the acid value becomes 5 or less, the pressure is gradually reduced, the reaction is continued at 1 mmHg, excess alcohol is removed, and the polyester has a primary hydroxyl group at the terminal and no secondary hydroxyl group. A polyol was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.5 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 5.0 mgKOH / g, a hydroxyl value of 49 mgKOH / g, and a number average molecular weight of about 2,100 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. A reaction product (A-6) of and trimellitic anhydride was obtained.

(Synthesis Example 7) Reaction product (A-7)
40 parts of ethylene glycol, 80 parts of diethylene glycol, 100 parts of 1,4-butanediol, 120 parts of isophthalic acid, 140 parts of terephthalic acid in a reaction vessel equipped with a stirrer, a temperature system, a reflux condenser, a dropping tank and a nitrogen gas introduction pipe. 100 parts of adipic acid was charged, and the temperature was raised to 260 ° C. while stirring under a nitrogen stream. After continuing the reaction until the acid value becomes 5 or less, the pressure is gradually reduced, the reaction is continued at 1 mmHg, excess alcohol is removed, and the polyester has a primary hydroxyl group at the terminal and no secondary hydroxyl group. A polyol was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.5 part of trimellitic anhydride was added. A polyester polyol having a primary hydroxyl group having an acid value of 5.0 mgKOH / g, a hydroxyl value of 48 mgKOH / g, and a number average molecular weight of about 2,200 after raising the temperature to 150 ° C. with stirring under a nitrogen stream and reacting for 3 hours. A reaction product (A-7) of and trimellitic anhydride was obtained.

The obtained reaction product (A) is shown in Table 1.

[Synthesis of polyol (B) having a secondary or tertiary hydroxyl group at the end]
(Synthesis Example 8) Polyol (B1-1)
110 parts of terephthalic acid, 250 parts of adipic acid, 200 parts of diethylene glycol, 75 parts of neopentyl glycol, and 200 parts of propylene glycol were charged into a reaction vessel and heated to 200 ° C. while stirring under a nitrogen gas stream to carry out an esterification reaction. .. When the acid value becomes 10.0 mgKOH / g or less, the reaction temperature is set to 200 ° C., the inside of the reaction vessel is gradually depressurized, and the reaction is carried out at 1.3 kPa or less. The acid value is 0.4 mgKOH / g and the hydroxyl value is 120 mgKOH / g. , A polyol (B1-1) which is a polyester polyol having a secondary hydroxyl group at the terminal and having a number average molecular weight of about 5,800 was obtained.

(Synthesis Example 9) Polyol (B1-2)
100 parts of terephthalic acid, 200 parts of adipic acid, 250 parts of diethylene glycol, 50 parts of neopentyl glycol, and 300 parts of propylene glycol were charged in a reaction vessel and heated to 200 ° C. while stirring under a nitrogen gas stream to carry out an esterification reaction. .. When the acid value becomes 10.0 mgKOH / g or less, the reaction temperature is set to 200 ° C., the inside of the reaction vessel is gradually depressurized, and the reaction is carried out at 1.3 kPa or less. The acid value is 0.4 mgKOH / g and the hydroxyl value is 150 mgKOH / g. , A polyol (B1-2) which is a polyester polyol having a secondary hydroxyl group at the terminal and having a number average molecular weight of about 4,200 was obtained.

(Synthesis Example 10) Polyol (B1-3)
300 parts of polypropylene glycol with a number average molecular weight of about 400, 200 parts of polypropylene glycol with a number average molecular weight of about 2,000, 300 parts of triol with a number average molecular weight of about 400 obtained by adding polypropylene glycol to glycerin, 4,4'-diphenylmethane 150 parts of diisocyanate was charged into a reaction vessel and heated at 90 ° C. for 3 hours while stirring under a nitrogen gas stream to carry out a urethanization reaction. The disappearance of isocyanate groups was confirmed by IR, and the hydroxyl value was 150 mgKOH / g. A polyol (B1-3), which is a polyether polyurethane resin having a secondary hydroxyl group at the terminal and having a number average molecular weight of about 5,000, was obtained.

(Synthesis Example 11) Polyol (B1-4)
60 parts of terephthalic acid, 200 parts of adipic acid, 100 parts of 1,6-hexanediol and 150 parts of 1,3-butanediol are charged in a reaction vessel and heated to 200 ° C. while stirring under a nitrogen gas stream for esterification reaction. Was done. When the acid value becomes 10.0 mgKOH / g or less, the reaction temperature is set to 200 ° C., the inside of the reaction vessel is gradually depressurized, and the reaction is carried out at 1.3 kPa or less. A polyester polyol having a hydroxyl group was obtained.
Next, 100 parts of the obtained polyester polyol was placed in a separately prepared flask, and 0.5 part of trimellitic anhydride was added. Then, the temperature is raised to 150 ° C. with stirring under a nitrogen stream and reacted for 3 hours to have a secondary hydroxyl group having an acid value of 4.5 mgKOH / g, a hydroxyl value of 140 mgKOH / g, and a number average molecular weight of about 4,800. A polyol (B1-4), which is a reaction product of a polyester polyol and trimellitic anhydride, was obtained.

(Synthesis Example 12) Polyol (B2-1)
110 parts of terephthalic acid, 250 parts of adipic acid, 100 parts of diethylene glycol, 200 parts of 3-methyl-1,3-butylene glycol, 200 parts of 2,5-dimethyl-2,5-hexanediol were charged into the reaction vessel, and a nitrogen gas stream was added. The esterification reaction was carried out by heating to 200 ° C. with stirring underneath. When the acid value becomes 10.0 mgKOH / g or less, the reaction temperature is set to 200 ° C., the inside of the reaction vessel is gradually depressurized, and the reaction is carried out at 1.3 kPa or less. The acid value is 0.4 mgKOH / g and the hydroxyl value is 120 mgKOH / g. , A polyester polyol (B2-1) having a number average molecular weight of about 5,800 and having a tertiary hydroxyl group at the terminal was obtained.

The obtained polyol (B) is shown in Table 2.

The abbreviations in Table 2 are shown below.
PPG-400: Polypropylene glycol with a number average molecular weight of about 400 PPG-2000: Polypropylene glycol with a number average molecular weight of about 2,000 4,4'-MDI: 4,4'-diphenylmethane diisocyanate

[Manufacturing of polyisocyanate component]
(Synthesis Example 13) Polyisocyanate (C-1)
150 parts of polypropylene glycol having a number average molecular weight of about 400, 60 parts of polypropylene glycol having a number average molecular weight of about 2,000, 50 parts of triol having a number average molecular weight of about 400 with polypropylene glycol added to glycerin, 450 parts of 4,4'-diphenylmethane diisocyanate. Is charged into a reaction vessel and heated at 80 ° C. to 90 ° C. for 3 hours while stirring under a nitrogen gas stream to carry out a urethanization reaction, and a structure derived from polypropylene glycol having an isocyanate group content of 20.5% by mass. Polyisocyanate (C-1), which is an aromatic polyisocyanate having the above, was obtained.

(Synthesis Example 14) Polyisocyanate (C-2)
300 parts of a mixture of 2,4'-diphenylmethane diisocyanate and 4,4'-diphenylmethane diisocyanate (product name: Luplanate MI, manufactured by BASF), 300 parts of Polymeric MDI (product name: Luplanate M20S, manufactured by BASF), nitrogen gas stream. The mixture was uniformly mixed at 80 ° C. with stirring underneath to obtain polyisocyanate (C-2), which is an aromatic polyisocyanate.

(Synthesis Example 15) Polyisocyanate (C-3)
50 parts of the biuret body of xylylene diisocyanate and 450 parts of the trimer of hexamethylene diisocyanate obtained by reacting a part of the isocyanate group with isobutanol are uniformly mixed at 80 ° C. with stirring under a nitrogen gas stream. Obtained polyisocyanate (C-3), which is an aliphatic polyisocyanate.

[Manufacturing of solvent-free adhesive composition]
[Example 1] (Adhesive composition (D-1))
30 parts of the reaction product (A-1) and 60 parts of the polyol (B1-1) are charged in the flask, and 5 parts of polypropylene glycol having a number average molecular weight of about 400 and 2-methyl-1,3- are further charged as a diluent. Five parts of propanediol was charged and stirred at 80 ° C. for 30 minutes. After cooling the obtained mixture to room temperature, 100 parts of the mixture, 60 parts of polyisocyanate (C-1), and 20 parts of polyisocyanate (C-2) are mixed to form a solvent-free adhesive composition ( D-1) was obtained.

[Examples 2 to 16, Comparative Examples 1 to 6] (Adhesive Compositions (D-2 to D-22))
Solvent-free adhesive compositions (D-2 to D-22) were obtained by the same operations as in Example 1 except that the materials and blending amounts shown in Table 3 were used.

[Evaluation of solvent-free adhesive composition]
The following evaluation was carried out on the obtained solvent-free adhesive composition. The results are shown in Table 3.

[Pot life]
The viscosities of the obtained solvent-free adhesive composition immediately after compounding and after storage at 40 ° C. for 30 minutes after compounding were measured using a cone plate viscometer CV-1S manufactured by Toa Kogyo Co., Ltd., respectively. The temperature at the time of measurement was 40 ° C. Evaluation was performed according to the following criteria based on the change in viscosity before and after storage.
A: The viscosity after storage is less than twice the viscosity immediately after compounding (good).
B: The viscosity after storage is 2 times or more and less than 3 times the viscosity immediately after compounding (usable).
C: The viscosity after storage is 3 times or more and less than 4 times the viscosity immediately after compounding (cannot be used).
D: The viscosity after storage is 4 times or more and less than 5 times the viscosity immediately after compounding (defective).

[Preparation of laminate]
Printing ink (Rio Alpha R631 White, manufactured by Toyo Ink Co., Ltd.) is mixed with ethyl acetate / IPA solvent (mass ratio 70/30) so that the viscosity becomes 16 seconds (25 ° C, Zahn Cup No. 3). Diluted to. Diluted printing ink on a 12 μm-thick polyethylene terephthalate film (“Ester film E5102” manufactured by Toyobo Co., Ltd., hereinafter referred to as PET) is printed at a printing speed of 50 m / min using a gravure proofing machine equipped with a solid plate having a plate depth of 35 μm. After printing in, it was dried at 50 ° C. The thickness of the print layer was in the range of 0.5 to 1 μm.
Next, a solvent-free adhesive composition was applied onto the printed layer of the obtained laminate using a solvent-free test coater at a temperature of 60 ° C., a coating speed of 200 m / min, and a solid content coating amount of 2.0 g / m. ^It was applied in 2.
Next, using a laminator in a room temperature environment, an adhesive coating was applied to the aluminum-deposited surface of a 12 μm-thick aluminum vapor-deposited film (“Dialaster H27” manufactured by Reiko Co., Ltd., hereinafter referred to as VM-PET) and the obtained laminate. The faces were pasted together.
Next, the solvent-free adhesive composition was applied onto the PET on the VM-PET side of the obtained laminate in the same manner as before, and the coated surface was subjected to a thickness of 100 μm using a laminator in a room temperature environment. After laminating with a linear low-density polyethylene film (“TUX-FCD” manufactured by Mitsui Tocello Co., Ltd., hereinafter referred to as LLDPE) that has been subjected to surface corona discharge treatment, the adhesive is cured by keeping it warm at 40 ° C. for 2 days. A laminate having the composition of PET / printing layer / adhesive layer / VM-PET / adhesive layer / LLDPE was obtained.

[Floating resistance due to bending of the heat seal part]
The obtained laminate was cut into a size of 6 cm in width and 10 cm in length, and bent so as to overlap the LLDPE surfaces to obtain a size of 6 cm in width and 5 cm in length.
^{Next, a heat seal treatment (180 ° C., 2.0 kg / m 2} , 1.0 second) was performed on a range of 3 cm from the crease (width 6 cm, length 3 cm), and then the mixture was allowed to cool at room temperature for about 10 seconds.
Next, the heat-sealed portion was bent in half, and the bent portion was strongly handled 5 times back and forth at the corner of the desk, and when the crease was lightly widened, it was visually confirmed whether or not a white line was generated in the valley portion. Based on its appearance, it was judged according to the following criteria.
A: No white line or white line less than 1/30 of the crease occurs (good)
B: White lines are generated (usable) at 1/30 or more and less than 1/3 of the crease.
C: White lines occur in 1/3 or more of the creases (cannot be used)
D: Wide white line around the crease (defective)

From the evaluation results, the solvent-free adhesive composition of the present invention showed an excellent pot life and an effect of suppressing floating when the heat-sealed portion was bent.
In particular, using the aromatic polyisocyanate component, the content of the reaction product (A) with respect to the total mass of the polyol component is 25 to 45% by mass, and the number of NCO moles in all the components in the solvent-free adhesive composition. The ratio of / OH molar number is 1.0 to 1.5, and the amount of the compound having an acid anhydride group used is 0.4 to 0.7% by mass with respect to the polyester polyol having a primary hydroxyl group. 3, 11, 12, 14 to 16 have both excellent pot life and floating resistance.
On the other hand, since the content of the reaction product (A) in D-2 was less than the above range, the floating resistance was slightly lowered, and in D-4, the pot life was slightly deteriorated because it was more than the above range. In D-6, the ratio of the number of moles of NCO / the number of moles of NCO in all the components in the solvent-free adhesive composition is smaller than the above range, so that the floating resistance is slightly lowered, and in D-7, the pot life is larger than the above range. Has deteriorated slightly. Since the content of the compound having an acid anhydride group with respect to the polyester polyol having a primary hydroxyl group is less than the above range in D-8, the floating resistance is slightly lowered, and in D-9, the pot life is slightly deteriorated because it is more than the above range. .. In D-5, the aliphatic polyisocyanate could not satisfy the heat resistance, and the floating resistance was lowered. Since D-10 has a small amount of aromatic dicarboxylic acid in the reaction product (A), its heat resistance and floating resistance are slightly lowered, and D-12 and D-13 have a high viscosity due to its large amount of aromatic dicarboxylic acid. Pot life has deteriorated slightly. Since D-15 did not contain an ester in the polyol (B), the floating resistance was slightly lowered as well as the heat resistance.
Based on the above, the adhesive composition of the present invention exhibits resistance to floating that tends to occur when the heat-sealed portion is bent by containing an acid-modified terminal primary polyester polyol, and is concerned about acid modification. The increase in reactivity was suppressed by using a secondary or tertiary polyester polyol in combination, and both bending floating resistance and pot life were achieved.

Claims (6)

A two-component curable solvent-free adhesive composition containing a polyol component and a polyisocyanate component.
The polyol component has a reaction product (A) of a polyester polyol having a primary hydroxyl group and a compound having an acid anhydride group, and a secondary or tertiary hydroxyl group at the terminal, and has a number average molecular weight of 1,. Contains 000 or more and 10,000 or less polyol (B)
A solvent-free adhesive composition in which the content of the reaction product (A) is 10 to 60% by mass with respect to the total mass of the polyol component. The solvent-free adhesive composition according to claim 1, wherein the polyvalent carboxylic acid constituting the polyester polyol having a primary hydroxyl group contains adipic acid and an aromatic dicarboxylic acid. The solvent-free adhesive composition according to claim 2, wherein the content of the aromatic dicarboxylic acid is 25 to 40% by mass with respect to the total mass of the polyester polyol having a primary hydroxyl group. The solvent-free adhesive composition according to any one of claims 1 to 3, wherein the polyisocyanate component contains an aromatic polyisocyanate or a derivative thereof. The solvent-free adhesive composition according to any one of claims 1 to 4, wherein the content of the reaction product (A) is 25 to 45% by mass with respect to the total mass of the polyol component. A laminate in which an adhesive layer composed of the solvent-free adhesive composition according to any one of claims 1 to 5 is laminated between at least two sheet-like substrates.