CN111836866A

CN111836866A - Reactive adhesive, laminated film and packaging material

Info

Publication number: CN111836866A
Application number: CN201980018507.0A
Authority: CN
Inventors: 德永千勇; 郑康云; 田边英男
Original assignee: DIC Corp
Current assignee: DIC Corp
Priority date: 2018-03-27
Filing date: 2019-03-14
Publication date: 2020-10-27
Anticipated expiration: 2039-03-14
Also published as: JPWO2019188334A1; WO2019188334A1; CN111836866B; JP6675595B2; TW201942296A

Abstract

A reactive adhesive comprising a polyisocyanate composition (X), a polyol composition (Y) and pyromellitic anhydride, wherein the reactive adhesive contains 0.2 to 2.0% by weight of pyromellitic anhydride based on the total solid content of the reactive adhesive; and a laminated film in which an adhesive layer is laminated between a first plastic film and a second plastic film, wherein the adhesive layer is a layer of the reactive adhesive described above. The reactive adhesive preferably further contains 3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furanyl) -1, 3-isobenzofurandione, or gallic acid.

Description

Reactive adhesive, laminated film and packaging material

Technical Field

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

Background

Laminated films (sometimes referred to as laminated films) used for various packaging materials, labels, and the like are laminated with various plastic films, metal foils, paper, and the like to impart appearance, functionality, storage stability, convenience, and transportability, and particularly, packages formed by forming the laminated films into a bag shape are used as packages for foods, pharmaceuticals, detergents, and the like. As an adhesive used for laminating these films, a reactive adhesive (also referred to as a two-component adhesive) in which a polyisocyanate composition and a polyol composition are combined is known.

An adhesive for a laminated film for food packaging is required to have excellent content resistance property, i.e., no influence on the appearance of a packaging film after a certain period of time has elapsed after a food packaging bag made of a food packaging film is filled with a content (e.g., a food) and subjected to a sterilization treatment. For these evaluations, acid resistance and oil resistance are generally evaluated, and for example, patent document 1 discloses that a composition for a polyurethane adhesive, which is obtained by blending an organic polyisocyanate, an oxyacid of phosphorus or a derivative thereof, a carboxylic acid compound or an anhydride thereof, and an epoxy resin with a polyol, exhibits high hot water resistance and acid resistance even for highly acidic foods. Patent document 2 discloses an adhesive for food packaging films, which contains a urethane resin obtained by blending (a) a polyol component, (B) an isocyanate component, and (C) an aromatic compound having both a phenolic hydroxyl group and a carboxyl group or an ester group, and which is excellent in peel strength and resistance after a hot water sterilization treatment under pressure for contents having a weight ratio of cereal vinegar/salad oil/tomato puree of 1/1/1.

However, there are various types of food additives, and ethyl maltol added to food as a flavor, for example, deteriorates the strength of an adhesive after retort sterilization. However, adhesives having resistance to ethyl maltol have not been examined so far.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2-84482

Patent document 2: japanese patent laid-open publication No. 2015-113411

Disclosure of Invention

Problems to be solved by the invention

The invention provides a reactive adhesive which improves the reduction of adhesive strength after retort sterilization caused by ethyl maltol.

Means for solving the problems

The present inventors have solved the above problems by providing a reactive adhesive comprising a polyisocyanate composition (X), a polyol composition (Y) and pyromellitic anhydride, wherein the reactive adhesive contains 0.2 to 2.0% by weight of pyromellitic anhydride based on the total solid content of the reactive adhesive.

That is, the present invention provides a reactive adhesive comprising a polyisocyanate composition (X), a polyol composition (Y) and pyromellitic anhydride, wherein the pyromellitic anhydride is contained in an amount of 0.2 to 2.0% by weight based on the total solid content of the reactive adhesive.

The present invention also provides a laminated film in which an adhesive layer is laminated between a first plastic film and a second plastic film, wherein the adhesive layer is the layer of the reactive adhesive described above.

The present invention also provides a packaged article obtained by forming a laminated film, in which an adhesive layer is laminated between a first plastic film and a second plastic film, into a bag-like shape, wherein the adhesive layer is the layer of the reactive adhesive described above.

Effects of the invention

Since the decrease in the adhesion strength after retort sterilization due to ethyl maltol is improved, the reactive adhesive of the present invention can be suitably used as a food packaging bag to which ethyl maltol as a flavor is added.

Detailed Description

(reactive adhesive)

The reactive adhesive is characterized by comprising a polyisocyanate composition (X), a polyol composition (Y) and pyromellitic anhydride, and is characterized by comprising 0.2-2.0 wt% of pyromellitic anhydride relative to the total solid content of the reactive adhesive.

Among them, the pyromellitic anhydride is preferably contained in an amount of 0.2 to 1.5 wt%, and most preferably 0.3 to 0.8 wt%, based on the total solid content of the reactive adhesive.

(pyromellitic anhydride)

Pyromellitic anhydride used in the present invention is a compound having the following structure.

In the present invention, in addition to the above pyromellitic anhydride, 3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furyl) -1, 3-isobenzofurandione or gallic acid is preferably used in combination.

When used in combination, the 3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furanyl) -1, 3-isobenzofurandione is preferably contained in an amount of 0.2 to 2.0% by weight, most preferably 0.3 to 1.0% by weight, based on the total solid content of the reactive binder.

The gallic acid is preferably contained in an amount of 0.2 to 2.0 wt%, and most preferably 0.3 to 1.0 wt%, based on the total solid content of the reactive adhesive.

In the present invention, the polyisocyanate composition (X) and the polyol composition (Y) used as the reactive adhesive can be used in combination without any particular limitation except that the pyromellitic anhydride is added in a specific amount.

(polyisocyanate composition (X))

The polyisocyanate composition (X) used in the present invention is a composition containing a polyisocyanate compound as a main component. The polyisocyanate compound used in the present invention is not particularly limited, and known ones can be used, and it may be used alone or two or more kinds may be mixed and used.

Examples thereof include: polyisocyanates having an aromatic structure in the molecular structure, such as toluene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (1, 5-naphthalene diisocyanate), triphenylmethane triisocyanate, and xylene diisocyanate, and compounds in which a part of the NCO groups of these polyisocyanates is modified with carbodiimide; allophanate (allophanate) compounds derived from these polyisocyanates; polyisocyanates having an alicyclic structure in the molecular structure, such as isophorone diisocyanate, 4' -methylenebis (cyclohexyl isocyanate), and 1, 3- (isocyanotomethyl) cyclohexane; linear aliphatic polyisocyanates such as 1, 6-hexamethylene diisocyanate, lysine diisocyanate and trimethylhexamethylene diisocyanate, and allophanate compounds thereof; isocyanurate bodies of these polyisocyanates; allophanate bodies derived from these polyisocyanates; biuret bodies derived from these polyisocyanates; adducts obtained by modifying trimethylolpropane; polyisocyanates which are reaction products of the above-mentioned various polyisocyanates with a polyol component, and the like.

In addition, it is preferable from the viewpoint of imparting flexibility to the laminate and improving practical packaging properties by reacting a polyisocyanate having an aromatic structure in the molecular structure and a linear aliphatic polyisocyanate with a polyol compound. In this case, the linear aliphatic polyisocyanate can be introduced into the polyisocyanate compound while forming a urethane bond or an allophanate bond when reacting with a hydroxyl group in the polyol compound. When the polyisocyanate having an aromatic structure and the linear aliphatic polyisocyanate are used in combination, the ratio of the polyisocyanate having an aromatic structure to the linear aliphatic polyisocyanate is preferably 99/1 to 70/30 on a mass basis from the viewpoint of lowering the viscosity.

Here, the reaction ratio of the polyisocyanate compound and the polyol compound is preferably in the range of 1.0 to 5.0 in terms of the balance between cohesive force and flexibility of the adhesive coating film [ isocyanate group/hydroxyl group ].

Specific examples of the polyol compound which reacts with the polyisocyanate having an alicyclic structure or an aromatic structure in the molecular structure include chain aliphatic diols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutylene glycol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, and bishydroxyethoxybenzene; alicyclic diols such as 1, 4-cyclohexanediol and 1, 4-cyclohexanedimethanol; trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane and pentaerythritol; bisphenols such as bisphenol a, bisphenol F, hydrogenated bisphenol a, and hydrogenated bisphenol F;

a dimer diol; polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as the above-mentioned diol or trifunctional or tetrafunctional aliphatic alcohol;

a polyester polyol (1) which is a reaction product of a polyester obtained by ring-opening polymerization of a cyclic ester compound such as propiolactone, butyrolactone, -caprolactone, sigma-valerolactone or β -methyl-sigma-valerolactone and the diol or trifunctional or tetrafunctional aliphatic alcohol;

a polyester polyol (2) obtained by reacting a polyhydric alcohol such as the chain aliphatic diol, the alicyclic diol, the dimer diol, the bisphenol, or the polyether polyol with a polycarboxylic acid;

a polyester polyol (3) obtained by reacting the trifunctional or tetrafunctional aliphatic alcohol with a polycarboxylic acid;

a polyester polyol (4) obtained by reacting a bifunctional polyol, the trifunctional or tetrafunctional aliphatic alcohol, and a polycarboxylic acid;

polyester polyol (5) which is a polymer containing a hydroxy acid such as dimethylolpropionic acid or castor oil fatty acid;

mixtures of the above polyester polyols (1), (2), (3), (4), (5) and polyether polyols;

castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil which is a hydrogenated product of castor oil, and 5 to 50 mol adducts of alkylene oxides of castor oil.

Here, as the polycarboxylic acid used for producing the polyester polyol (2), (3) or (4), for example: acyclic aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, and fumaric acid; alicyclic dicarboxylic acids such as 1, 3-cyclopentanedicarboxylic acid and 1, 4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, 1, 4-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and 1, 2-bis (phenoxy) ethane-p, p' -dicarboxylic acid; anhydrides or ester-forming derivatives of these aliphatic or aromatic dicarboxylic acids; and polybasic acids such as p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, ester-forming derivatives of these dihydroxy carboxylic acids, and dimer acid.

Among these, from the viewpoint of wettability to a substrate, preferred is a polyisocyanate compound obtained by reacting the polyether polyol with the polyisocyanate compound.

The polyisocyanate compound preferably has a weight average molecular weight (Mw) in the range of 3000 to 10000 from the viewpoint of shortening the curing time and ensuring appropriate practical packaging properties, and preferably has an isocyanate content of 5 to 20 mass% by a titration method (using di-n-butylamine) from the viewpoint of achieving an appropriate resin viscosity and excellent coatability.

(polyol composition (Y))

The polyol composition (Y) used in the present invention is a composition containing a polyol compound as a main component. The polyhydric alcohol compounds may be used alone or in combination of two or more.

Specific examples thereof include: glycols such as ethylene glycol, propylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, 1, 6-hexanediol, neopentyl glycol, methylpentanediol, dimethylbutylene glycol, butylethylpropanediol, diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, bishydroxyethoxybenzene, 1, 4-cyclohexanediol, 1, 4-cyclohexanedimethanol, and triethylene glycol; trifunctional or tetrafunctional aliphatic alcohols such as glycerin, trimethylolpropane and pentaerythritol; bisphenols such as bisphenol a, bisphenol F, hydrogenated bisphenol a, and hydrogenated bisphenol F; a dimer diol;

polyether polyols obtained by addition polymerization of alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide (styrene oxide), epichlorohydrin, tetrahydrofuran, and cyclohexylene in the presence of a polymerization initiator such as the above-mentioned diol or trifunctional or tetrafunctional aliphatic alcohol; polyether urethane polyol obtained by further subjecting the polyether polyol to high molecular weight polymerization with the aromatic or aliphatic polyisocyanate;

a polyester polyol (1) which is a reaction product of a polyester obtained by ring-opening polymerization of a cyclic ester compound such as propiolactone, butyrolactone, -caprolactone, sigma-valerolactone, or β -methyl-sigma-valerolactone, and a polyhydric alcohol such as the above-mentioned diol, glycerin, trimethylolpropane, or pentaerythritol; a polyester polyol (2) obtained by reacting a bifunctional polyol such as the diol, dimer diol, or bisphenol with a polycarboxylic acid; a polyester polyol (3) obtained by reacting the trifunctional or tetrafunctional aliphatic alcohol with a polycarboxylic acid; a polyester polyol (4) obtained by reacting a bifunctional polyol, the trifunctional or tetrafunctional aliphatic alcohol, and a polycarboxylic acid; polyester polyol (5) which is a polymer containing a hydroxy acid such as dimethylolpropionic acid or castor oil fatty acid;

polyester polyether polyols obtained by reacting the polyester polyols (1) to (5) with the polyether polyol and an aromatic or aliphatic polyisocyanate; polyester-polyurethane polyols obtained by polymerizing the above polyester polyols (1) to (5) with an aromatic or aliphatic polyisocyanate; mixtures of the polyester polyols (1) to (5) with polyether polyols; castor oil-based polyols such as castor oil, dehydrated castor oil, hydrogenated castor oil which is a hydrogenated product of castor oil, and 5 to 50 mol adducts of alkylene oxides of castor oil. The weight average molecular weight (Mw) of the polyol used is preferably 400 to 5000.

Among them, as the polycarboxylic acid, for example: aliphatic dicarboxylic acids such as succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic anhydride, fumaric acid, 1, 3-cyclopentanedicarboxylic acid, and 1, 4-cyclohexanedicarboxylic acid; aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 1, 4-naphthalenedicarboxylic acid, 2, 5-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and 1, 2-bis (phenoxy) ethane-p, p' -dicarboxylic acid; and acid anhydrides or ester-forming derivatives of these aliphatic or dicarboxylic acids; polybasic acids such as p-hydroxybenzoic acid, p- (2-hydroxyethoxy) benzoic acid, ester-forming derivatives of these dihydroxy carboxylic acids, and dimer acids.

(solvent)

The reactive adhesive used in the present invention is an adhesive that is cured by a chemical reaction between an isocyanate group and a hydroxyl group, and a solvent-type or solvent-free adhesive can be used. In the present invention, the "solvent" of the solvent-type adhesive means an organic solvent having high solubility in which the polyisocyanate compound or the polyol compound used in the present invention can be dissolved, and the "solvent-free" means that the organic solvent having high solubility is not contained. Specific examples of the highly soluble organic solvent include toluene, xylene, methylene chloride, tetrahydrofuran, methyl acetate, ethyl acetate, n-butyl acetate, acetone, Methyl Ethyl Ketone (MEK), cyclohexanone, n-hexane, and cyclohexane. Among them, toluene, xylene, dichloromethane, tetrahydrofuran, methyl acetate, and ethyl acetate are known as organic solvents having extremely high solubility.

In the reactive adhesive used in the present invention, the blending ratio of the polyisocyanate composition (X) and the polyol composition (Y) is preferably in the range of 0.6 to 5.0 in the equivalent ratio [ isocyanate group/hydroxyl group ] of the isocyanate group in the polyisocyanate compound contained in the polyisocyanate composition (X) to the hydroxyl group in the polyol compound contained in the polyol composition (Y), from the viewpoint of excellent adhesive strength and heat resistance at the time of heat sealing, and is particularly preferably in the range of 1.0 to 3.5 from the viewpoint of remarkable these properties.

(aliphatic cyclic amide Compound)

As described in detail above, the reactive adhesive of the present invention contains the polyol component a and the isocyanate component B as essential components, but when an aliphatic cyclic amide compound is further mixed with either the polyol component a or the isocyanate component B, or added as the 3 rd component at the time of application, elution of harmful low-molecular-weight chemical substances such as aromatic amines into the contents in the laminated packaging can be effectively suppressed.

Examples of the aliphatic cyclic amide compound used herein include: valerolactam, caprolactam, omega-heptanolactam, eta-octanolactam (captam), beta-propiolactam (beta-propiolactam), and the like. Among these, caprolactam is preferable from the viewpoint of having an excellent effect of reducing the elution amount of low-molecular chemical substances. In addition, the amount of the aliphatic cyclic amide compound is preferably in the range of 0.1 to 5 parts by mass per 100 parts by mass of the polyol component a.

(catalyst)

In the present invention, by using a catalyst, elution of harmful low-molecular-weight chemical substances represented by aromatic amines into the contents in the laminate package can be effectively suppressed.

The catalyst used in the present invention is not particularly limited as long as it promotes the urethanization reaction, and for example, a metal-based catalyst, an amine-based catalyst, Diazabicycloundecene (DBU), an aliphatic cyclic amide compound, a titanium chelate complex, or the like can be used.

The metal-based catalyst includes metal complexes, inorganic metal-based catalysts, and organic metal-based catalysts, and the metal complexes are specifically selected from the group consisting of Fe (iron), Mn (manganese), Cu (copper), Zr (zirconium), and Th (B)Examples of acetylacetonates of metals in the group consisting of thorium), Ti (titanium), Al (aluminum), and Co (cobalt) include: iron acetylacetonate, manganese acetylacetonate, copper acetylacetonate, zirconium acetylacetonate, etc., but among these, from the viewpoint of toxicity and catalyst activity, iron acetylacetonate (fe (acac))₃) Or manganese acetylacetonate (Mn (acac)₂)。

Examples of the inorganic metal catalyst include catalysts selected from Fe, Mn, Cu, Zr, Th, Ti, Al, Co, and the like.

Examples of the organometallic catalyst include tin acetate (tin diacetate), tin octylate (tin dioleate), tin oleate (tin dioleate), tin laurate (tin dilaurate), dibutyltin oxide (dibutyl tin oxide), dibutyltin diacetate (dibutyl tin diacetate), dibutyltin dilaurate, dibutyltin dichloride, dioctyltin dilaurate, nickel octylate, nickel naphthenate, cobalt octylate, cobalt naphthenate, bismuth octylate, and bismuth naphthenate. Among these, preferred compounds are organotin catalysts, and tin octylate and dibutyltin dilaurate are more preferred.

The tertiary amine catalyst is not particularly limited if it is a compound having the above structure, and examples thereof include: triethylenediamine, 2-methyltriethylenediamine, quinuclidine, 2-methyl quinuclidine, and the like. Among these, triethylene diamine and 2-methyltriethylene diamine are preferable because they have excellent catalytic activity and are industrially available.

Examples of the other tertiary amine catalyst include N, N, N ', N' -tetramethylethylenediamine, N, N, N ', N' -tetramethylpropylenediamine, N, N, N ', N' -pentamethyldiethylenetriamine, N, N, N ', N' -pentamethyl- (3-aminopropyl) ethylenediamine, N, N, N ', N' -pentamethyldipropylenetriamine, N, N, N ', N' -tetramethylhexamethylenediamine, bis (2-dimethylaminoethyl) ether, dimethylethanolamine, dimethylisopropanolamine, dimethylaminoethoxyethanol, N, N-dimethyl-N '- (2-hydroxyethyl) ethylenediamine, N, N-dimethyl-N' - (2-hydroxyethyl) propanediamine, N, N ', N' -tetramethylethylenediamine, N, N ', N' -pentamethyldiethylenetriamine, N, N, N ', N' -tetramethylhexamethylenediamine, bis (dimethylaminopropyl) amine, bis (dimethylaminopropyl) isopropanolamine, 3-quinuclidine, N, N, N ', N ' -tetramethylguanidine, 1, 3, 5-tris (N, N-dimethylaminopropyl) hexahydro-S-triazine, 1, 8-diazabicyclo [5.4.0] undecene-7, N-methyl-N ' - (2-dimethylaminoethyl) piperazine, N, N ' -dimethylpiperazine, dimethylcyclohexylamine, N-methylmorpholine, N-ethylmorpholine, 1-methylimidazole, 1, 2-dimethylimidazole, 1-isobutyl-2-methylimidazole, 1-dimethylaminopropylimidazole, N, N-dimethylhexanolamine, N-methyl-N ' - (2-hydroxyethyl) piperazine, N-quinoxalinone, N, N ' -dimethylhexanolamine, N-methyl-N ' - (2-hydroxyethyl) piperazine, N, N ', N ' -tetramethylguanidine, N-methyl-N ' - (2-dimethylaminoethyl) piperazine, N, N ' -dimethyl, 1- (2-hydroxyethyl) imidazole, 1- (2-hydroxypropyl) imidazole, 1- (2-hydroxyethyl) -2-methylimidazole, 1- (2-hydroxypropyl) -2-methylimidazole, and the like.

Examples of the aliphatic cyclic amide compound include: valerolactam, caprolactam, omega-enantholactam, eta-caprylolactam, beta-propiolactam, and the like. Of these, -caprolactam is more effective in promoting curing.

The titanium chelate complex is a compound whose catalytic activity is improved by irradiation with ultraviolet light, and is preferably a titanium chelate complex having an aliphatic or aromatic diketone as a ligand from the viewpoint of excellent curing acceleration effect. In the present invention, the ligand is preferably a ligand having an alcohol having 2 to 10 carbon atoms, in addition to an aromatic or aliphatic diketone, from the viewpoint of further enhancing the effect of the present invention.

In the present invention, the above-mentioned catalysts may be used alone or in combination.

The mass ratio of the catalyst is preferably in the range of 0.001 to 80 parts, and more preferably in the range of 0.01 to 70 parts, based on 100 parts of the mixed liquid of the polyisocyanate composition (X) and the polyol composition (Y).

The reactive adhesive of the present invention may be used in combination with a pigment as required. The pigment usable in this case is not particularly limited, and examples thereof include: the raw materials for the paint include organic pigments or inorganic pigments such as extender pigments, white pigments, black pigments, gray pigments, red pigments, brown pigments, green pigments, blue pigments, metal powder pigments, luminescent pigments, pearl pigments, etc., which are described in 1970 edition (edited by japan paint industries, inc.), and plastic pigments. As specific examples of these colorants, various colorants have been disclosed, and as organic pigments, for example: various insoluble azo pigments such as benzidine yellow, Hansayellow (Hansayellow), and lake red (lake red) 4R; soluble azo pigments such as lake red C, magenta (carmine)6B, and purplish red (Bordeaux) 10; various (copper) phthalocyanine-based pigments such as phthalocyanine blue and phthalocyanine green; various chlorine dye lakes such as rose bengal lake and methyl violet lake; various medium dye-based pigments such as quinoline lake and fast sky blue (fast sky blue); vat dye-based pigments such as anthraquinone-based pigments, thioindigo (thioindigo) -based pigments, perinone-based pigments, and the like; various quinacridone (quinacridone) pigments such as Cinquasia red B; various dioxazine pigments such as dioxazine violet (dioxazine violet); various azo condensation pigments such as Cromophtal; nigrosine and the like.

Examples of the inorganic pigment include: various chromates such as chrome yellow, zinc chromate, molybdate orange, etc.; various ferrocyanide compounds such as prussian blue; various metal oxides such as titanium oxide, zinc white, Mapico yellow, iron oxide red, chromium oxide 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 silicates such as calcium silicate and ultramarine; various carbonates such as calcium carbonate and magnesium carbonate; various phosphates such as cobalt violet and manganese violet; various metal powder pigments such as aluminum powder, gold powder, silver powder, copper powder, bronze powder, brass powder, and the like; these metallic flake pigments, mica flake pigments; metal pigments such as metal oxide-coated mica flake pigments and mica iron oxide pigments, and pearl pigments; graphite, carbon black, and the like.

Examples of the extender pigment include precipitated barium sulfate, shell powder (ご powder), precipitated calcium carbonate, heavy calcium carbonate, limestone (japanese: calcite), alumina white (alumina white), silica, hydrous fine silica (white carbon), ultrafine anhydrous silica (AEROSIL), silica sand (silica sand), talc, precipitated magnesium carbonate, bentonite, clay, kaolin, and loess.

Further, as the plastic pigment, for example: "GRANDOLL PP-1000" and "PP-2000S" available from DIC corporation.

The pigment used in the present invention is more preferably titanium oxide, an inorganic oxide such as zinc white, or carbon black as a black pigment, because of its excellent durability, weather resistance, and appearance.

The mass ratio of the pigment used in the present invention is 1 to 400 parts by mass relative to 100 parts by mass of the total of the isocyanate component B and the polyol component a, and more preferably 10 to 300 parts by mass in view of excellent adhesion, blocking resistance (blocking resistance) and the like.

(adhesion promoter)

In addition, an adhesion promoter may be used in combination with the reactive adhesive used in the present invention. Examples of the adhesion promoter include silane coupling agents, titanate coupling agents, aluminum coupling agents, and epoxy resins.

Examples of the silane coupling agent include: aminosilanes such as γ -aminopropyltriethoxysilane, γ -aminopropyltrimethoxysilane, N- β (aminoethyl) - γ -aminopropyltrimethyldimethoxysilane, and N-phenyl- γ -aminopropyltrimethoxysilane; epoxysilanes such as beta- (3, 4-epoxycyclohexyl) ethyltrimethoxysilane, gamma-glycidoxypropyltrimethoxysilane and gamma-glycidoxypropyltriethoxysilane; vinyl silanes such as vinyltris (β -methoxyethoxy) silane, vinyltriethoxysilane, vinyltrimethoxysilane and γ -methacryloxypropyltrimethoxysilane; hexamethyldisilazane, gamma-mercaptopropyltrimethoxysilane, and the like.

Examples of the titanate-based coupling agent include: titanium tetraisopropoxide, titanium tetra-n-butoxide, butyl titanate dimer, tetrastearyl titanate, titanium acetylacetonate, titanium lactate, tetraoctanediol titanate, titanium lactate, titanium tetrastearoxy, and the like.

Examples of the aluminum-based coupling agent include: aluminum (acetoacetoxy) diisopropoxide, and the like.

Examples of the epoxy resin include various epoxy resins such as general commercially available epi-bis (epi-bis) type, novolak type, β -methylepichlorohydrin type, cyclic oxirane type, glycidyl ether type, glycidyl ester type, polyglycol ether type, glycol ether type, epoxidized fatty acid ester type, polycarboxylic acid ester type, aminoglycidyl group type, resorcinol type, triglycidyl tris (2-hydroxyethyl) isocyanurate, neopentyl glycol diglycidyl ether, 1, 6-hexanediol diglycidyl ether, glycidyl acrylate, 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, phenol glycidyl ether, p-tert-butylphenyl glycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, glycidyl methacrylate, epoxy resin, Butyl glycidyl ether and the like.

(other additives)

The reactive adhesive used in the present invention may contain other additives than those described above, if necessary. Examples of the additive include a leveling agent, inorganic fine particles such as colloidal silica or alumina sol, polymethyl methacrylate-based organic fine particles, a defoaming agent, a sag inhibitor, a wetting dispersant, a viscosity modifier, an ultraviolet absorber, a metal deactivator, a peroxide decomposer, a flame retardant, a reinforcing agent, a plasticizer, a lubricant, a rust inhibitor, a fluorescent brightener, an inorganic infrared absorber, a flame retardant, an antistatic agent, a dehydrating agent, a known and conventional thermoplastic elastomer, a tackifier, a phosphoric acid compound, a melamine resin, and a reactive elastomer. The content of these additives can be appropriately adjusted and used within a range not impairing the function of the reactive adhesive used in the present invention.

These adhesion promoters and additives may be mixed with any of the components of the polyisocyanate composition (X) and the polyol composition (Y), or may be used as the 3 rd component to be mixed at the time of coating. Usually, a premix obtained by blending components other than the polyisocyanate composition (X) in the polyol composition (Y) is prepared in advance, and the premix is mixed with the polyisocyanate composition (X) immediately before application.

(laminated film)

The laminate film of the present invention is obtained by laminating an adhesive layer formed of the reactive adhesive between a first plastic film and a second plastic film. Specifically, the adhesive layer is obtained by applying the reactive adhesive to a first plastic film, laminating a second plastic film on the applied surface, and curing the adhesive layer. The coating may be carried out by any known method, but is generally carried out by gravure roll coating. The coating amount of the adhesive is 1.0 to 5.0g/m in terms of solid content²Preferably 1.5 to 4.0g/m²The coating conditions of (1) are used.

Further, a laminated film obtained by subjecting the first plastic film to gravure printing, flexo printing, inkjet printing or offset printing (offset printing) with a printing ink can be used, and even at this time, a good laminated appearance can be exhibited. The printing ink may be solvent-based, aqueous, or active energy ray-curable.

When the reactive adhesive used in the present invention is used, the adhesive is cured at normal temperature or under heating for 12 to 72 hours after lamination, and practical properties are exhibited.

Examples of the first plastic film used in this case include PET (polyethylene terephthalate) films, nylon films, OPP (biaxially stretched polypropylene) films, K-COAT films such as polyvinylidene chloride films, base films such as various vapor deposited films, and aluminum foils, and examples of the second plastic film include sealing films such as CPP (non-stretched polypropylene) films, VMCPP (aluminum vapor deposited non-stretched polypropylene) films, LLDPE (linear low density polyethylene), LDPE (low density polyethylene), HDPE (high density polyethylene), and VMLDPE (aluminum vapor deposited low density polyethylene) films.

(packaging)

The package of the present invention is formed by forming the laminated film into a bag shape, and specifically, the laminated film is formed into a package by heat sealing. In addition, when considering the use as a package, required performance (easy tearability or hand cutting (hand cutting)) and rigidity or durability (for example, impact resistance, pinhole resistance and the like) required as a package, other layers may be laminated as necessary. Usually, it is used in conjunction with a base layer, a paper layer, a second sealant layer, a nonwoven fabric layer, and the like. As a method of laminating other layers, a known method can be used. For example, an adhesive layer may be provided between the other layers and laminated by a dry lamination method, a heat sealing method, an extrusion lamination method, or the like. As the adhesive, the above-mentioned reactive adhesive can be used, and other one-component type urethane-based adhesives, epoxy-based adhesives, aqueous dispersions of acid-modified polyolefins, and the like can also be used.

Specific examples of the laminate structure include a first plastic film layer/adhesive layer/second plastic layer, a base material layer/adhesive layer/first plastic film layer/adhesive layer/second plastic layer using the first plastic layer as a barrier layer, or a second plastic layer/paper layer/bonding layer/first plastic film layer/bonding layer/second plastic, a second plastic layer/paper layer/polyolefin resin layer/base material layer/first plastic layer/bonding layer/second plastic layer, a paper layer/first plastic film layer/bonding layer/sealant layer applicable to paper containers, paper cups, etc., or a second plastic layer/bonding layer/first plastic layer/bonding layer/second plastic layer applicable to tubular containers, etc. These laminates may also have a print layer, a top coat layer, or the like, as necessary.

As the first plastic film layer, for example, a polyester resin film such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polylactic acid (PLA), or the like; polyolefin resin films such as polypropylene; a polystyrene resin film; polyamide resin films such as nylon 6 and parylene adipamide (MXD6 nylon); a polycarbonate resin film; a polyacrylonitrile resin film; a polyimide resin film; multilayer composites thereof (e.g., nylon 6/MXD 6/nylon 6, nylon 6/ethylene vinyl alcohol/nylon 6), blends, and the like. Among them, a layer having mechanical strength and dimensional stability is preferable. Among these, a film arbitrarily stretched in the biaxial direction is preferably used.

In addition, in order to provide the barrier function, the first plastic film layer may be a vapor deposition layer such as aluminum vapor deposition, silicon oxide vapor deposition, aluminum oxide vapor deposition, or silicon oxide-aluminum oxide binary vapor deposition, in addition to a soft metal foil such as an aluminum foil; organic barrier layers comprising vinylidene chloride resins, modified polyvinyl alcohol, ethylene vinyl alcohol copolymers, MXD nylon and the like.

As the second plastic film layer, conventionally known sealant resins can be used. Examples thereof include: polyolefin resins such as polyethylene (e.g., Low Density Polyethylene (LDPE)), Linear Low Density Polyethylene (LLDPE), and High Density Polyethylene (HDPE), acid-modified polyethylene, polypropylene (PP), acid-modified polypropylene, copolymerized polypropylene, ethylene-vinyl acetate copolymer, ethylene- (meth) acrylate copolymer, ethylene- (meth) acrylic acid copolymer, and ionomer. Among them, a polyethylene resin is preferable from the viewpoint of low-temperature sealability, and polyethylene is particularly preferable from the viewpoint of low cost. The thickness of the sealant layer is not particularly limited, but is preferably 10 to 60 μm, and more preferably 15 to 40 μm in consideration of processability to a packaging material, heat sealability, and the like. Further, by providing projections and depressions having a height difference of 5 to 20 μm in the sealant layer, the sealant layer can be provided with slidability or tearability of the packaging material.

Examples of the paper layer include natural paper and synthetic paper. The first and second sealant layers may be formed of the same material as the sealant layer. A printing layer may be provided on the outer surface or the inner surface of the base material layer and the paper layer, as required.

The "other layer" may also contain known additives, stabilizers, such as antistatic agents, easy-adhesion coating agents, plasticizers, slip agents, antioxidants, and the like. In order to improve adhesion when the film is laminated with another material, the "other layer" may be a layer obtained by subjecting the film surface to corona treatment, plasma treatment, ozone treatment, chemical treatment, solvent treatment, or the like as a pretreatment.

Examples of the packing material of the present invention include various types such as a three-sided sealed bag, a four-sided sealed bag, a gusseted packaging bag (gassetpacking bag), a pillow-shaped packaging bag (pillow packing bag), a gable top (gable top) type bottomed container, a Tetra Classic bag (Tetra Classic), a brick type (brick type), a tubular container, a paper cup, and a lid material. In the package of the present invention, an easy-opening treatment or a resealability mechanism may be appropriately provided.

The package of the present invention is industrially applicable not only as a package for food subjected to retort sterilization treatment but also as a package filled with general food, detergent, and medicine. Specific applications include, in addition to food packages, detergents, liquid detergents for washing medicines, liquid detergents for kitchens, liquid detergents for bathrooms, liquid soaps for bathrooms, liquid shampoos, liquid hair lotions, pharmaceutical tablets, and the like. In addition, the packaging material can also be used for packaging the secondary packaging material of the container.

[ examples ]

The contents and effects of the present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples. In the examples, "part" means "part by weight".

(polyisocyanate composition (X))

Preparation example 1 polyisocyanate composition (X1)

100 parts of Desmodur L-75(TMP-3TDI adduct, manufactured by Sumika Covestro Urethane Co., Ltd.) and 1.5 parts of pyromellitic anhydride (product of Daicel Co., Ltd.) were charged into a flask equipped with a stirrer, a thermometer and a nitrogen introduction tube, and the mixture was diluted with ethyl acetate to obtain a polyisocyanate composition (X1) in the form of NV 45% solution.

Preparation example 2 polyisocyanate composition (X2)

Desmodur L-75(TMP-3TDI adduct, manufactured by Sumika Covestro Urethane Co., Ltd.) was used.

Preparation example 3 polyisocyanate composition (X3)

Lupranate MP102 (a diphenylmethane diisocyanate prepolymer manufactured by BASF INOAC URETHANE Co., Ltd.) was used.

(polyol composition (Y))

(Synthesis example 1)

145 parts of terephthalic acid, 350 parts of isophthalic acid, 225 parts of adipic acid, 15 parts of sebacic acid, 85 parts of ethylene glycol, 310 parts of diethylene glycol, and 45 parts of neopentyl glycol were charged into a polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, a rectification tube, a moisture separator, and the like, and esterification was carried out at an internal temperature of 250 ℃. After the dehydration reaction, a polyester polyol a1 having a number average molecular weight of about 9000 was obtained.

(Synthesis example 2)

In a polyester reaction vessel equipped with a stirrer, a thermometer, a nitrogen inlet tube, a rectifying tube, a moisture separator and the like, 375 parts of isophthalic acid, 250 parts of adipic acid and 545 parts of diethylene glycol were charged, and an esterification reaction was carried out at an internal temperature of 240 ℃. After the dehydration reaction, a polyester polyol having a number average molecular weight of about 1500 was obtained. 100 parts of this polyester polyol and 78 parts of ethyl acetate were reacted with 18 parts of Cosmonate T-80 (manufactured by tolylene diisocyanate mitsui SKC polyurethane corporation) previously charged into a reaction vessel equipped with a stirrer, a thermometer, a nitrogen introduction tube, a cooling tube, and the like, to obtain a polyester-urethane polyol B1 having a number average molecular weight of about 4000.

Preparation example 4 polyol composition (Y1)

The polyester polyol a1 obtained in synthesis example 1 was dissolved and diluted with ethyl acetate to obtain a polyol composition (Y1) of a 70% solid content (hereinafter abbreviated as NV) solution.

Preparation example 5 polyol composition (Y2)

Pyromellitic anhydride (product of Daicel gmbh) was added to the polyester polyol a1 obtained in synthesis example 1 in an amount of 1.0% by weight in terms of solid content, and the mixture was dissolved and diluted with ethyl acetate to obtain a polyol composition (Y2) in the form of NV 70% solution.

Preparation example 6 polyol composition (Y3)

EPICLON B-4500(3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furanyl) -1, 3-isobenzofurandione, product of DIC Co., Ltd.) was added to the polyester polyol A1 obtained in Synthesis example 1 in an amount of 1% by weight as calculated as solid content, and the mixture was dissolved and diluted with ethyl acetate to obtain a polyol composition (Y3) as a NV 70% solution.

Preparation example 7 polyol composition (Y4)

Purified gallic acid (manufactured by DSP GOKYO FOOD & CHEMICAL Co., Ltd.) was added to the polyester polyol A1 obtained in Synthesis example 1 in an amount of 1.0% by weight in terms of solid content, and the resultant was dissolved and diluted with ethyl acetate to obtain a polyol composition (Y4) in the form of a NV 70% solution.

Preparation example 8 polyol composition (Y5)

Pyromellitic anhydride (product of Daicel Co., Ltd.) was added to the polyester-urethane polyol B1 obtained in Synthesis example 2 in an amount of 0.7% by weight in terms of solid content, and the mixture was dissolved and diluted with ethyl acetate to obtain a polyol composition (Y5) in the form of a NV 60% solution.

Comparative preparation example 1 polyol composition (YH1)

Purified gallic acid (manufactured by DSP GOKYO FOOD & CHEMICAL Co., Ltd.) was added to the polyester polyol A1 obtained in Synthesis example 1 in an amount of 1.0% by weight in terms of solid content, and the mixture was dissolved and diluted with ethyl acetate to obtain a polyol composition (YH1) in the form of NV 70% solution.

Comparative preparation example 2 polyol composition (YH2)

EPICLON B-4500(3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furanyl) -1, 3-isobenzofurandione, product of DIC Co., Ltd.) was added to the polyester polyol A1 obtained in Synthesis example 1 in an amount of 1% by weight as calculated as solid content, and dissolved and diluted with ethyl acetate to obtain a polyol composition (YH2) having NV 70%.

(mixing ratio)

The mixing ratios of the adhesives are shown in tables 1 and 2. In example 1, 1 part by weight of the isocyanate composition was added to 3 parts by weight of the polyol composition, and the NV 30% was adjusted with ethyl acetate. In examples 2, 3 and 4, the polyol composition and the isocyanate composition shown in table 1 were mixed in parts by weight, and the NV 30% was adjusted with ethyl acetate.

In comparative examples, as shown in table 2, 1 part by weight of the isocyanate composition was added to 5 parts by weight of the polyol composition, and the amount was adjusted to NV 30% with ethyl acetate.

(evaluation method of Peel Strength test after retort test and storage stability test)

(method of producing a multilayer film for evaluation)

Dry type using DL-600DXLaminator (ORIENT SOGYO CO., LTD., manufactured) was coated on the PET film printed with transparent or blue ink so that the solid content weight of the binder became 4.0g/m²After the solvent was volatilized by a drier (60 ℃/70 ℃/80 ℃), the aluminum foil was bonded to the surface of the aluminum foil. Then, the aluminum foil was coated on the surface opposite to the surface bonded to the PET film with the adhesive so that the solid content weight of the adhesive was 4.0g/m²After the solvent is dried, the CPP film is laminated to produce a laminated film. Subsequently, the laminated film was aged at 50 ℃ for 3 days to cure the adhesive coating film, thereby obtaining a laminated film of PET film/adhesive composition/aluminum foil/adhesive composition/CPP film.

The following films and inks were used.

PET film: e510212 μm manufactured by Toyobo STC corporation

Aluminum foil film: 9 μm aluminum foil O material manufactured by Toyo aluminum Co., Ltd

CPP membrane: trefin NO ZK-20770 μm manufactured by Toray corporation

Printing ink: DIC XS-853R 507Genshokuai K1

1. Post cure peel strength test

A test piece of 200 mm. times.15 mm was cut from the laminate film for evaluation prepared by the above method, and a T-peel test was performed at a peel speed of 300mm/min under an environment of 23 ℃ and 50% relative humidity by using a tensile strength tester (Shimadzu corporation) to measure the peel strength (N/15mm) of the aluminum foil/CPP film. The peel strength was satisfactory when it was 1N/15mm or more.

2-1. resistance test of Ethyl Maltol solution (Peel Strength evaluated immediately after retort Sterilization)

From the laminate film for evaluation prepared by the above method, pouches having a size of 120mm × 120mm were prepared, and a 0.3% ethyl maltol aqueous solution (mock food) was prepared as a content and filled with 50 g. For the fabricated pouches, retort sterilization treatment was performed at 121 ℃ for 30 minutes. Thereafter, the packaging bag was randomly selected, cut open, and cut into 100mm × 15mm test pieces.

2-2. resistance test of Ethyl Maltol solution (appearance evaluated immediately after retort Sterilization)

From the laminated film for evaluation prepared by the above method, a 120mm × 120 mm-sized pouch was prepared, and a 0.3% ethyl maltol aqueous solution (simulated food) as a content was prepared and filled with 50 g. For the fabricated pouches, retort sterilization treatment was performed at 121 ℃ for 30 minutes. Thereafter, the packaging bags were randomly selected to visually evaluate the appearance thereof.

2-3 resistance test for commercial food blended with Ethyl maltol (appearance evaluated immediately after retort sterilization)

The peel strength (N/15mm) between the aluminum foil and the CPP film of the test piece was measured in the same manner as in the above peel strength test, and the film appearance was visually evaluated immediately after sterilization.

Further, a commercially available food blended with ethyl maltol was changed to the above-described size in a small bag, and the film appearance after retort sterilization was visually evaluated.

3-1 resistance test of Ethyl Maltol solution (Peel Strength after 1 day at 80 ℃ after Sterilization)

From the laminated film for evaluation prepared by the above method, a 120mm × 120 mm-sized pouch was prepared, and a 0.3% ethyl maltol aqueous solution (simulated food) as a content was prepared and filled with 50 g. For the fabricated pouches, retort sterilization treatment was performed at 121 ℃ for 30 minutes. Thereafter, the packaging bag was stored in a thermostatic bath at 80 ℃ and, after 1 day, the peel strength (N/15mm) between the aluminum foil and the CPP film of the test piece was measured in the same manner as in the above peel strength test.

3-2 resistance test of Ethyl Maltol solution (appearance after 1 day at 80 ℃ C. after sterilization)

From the laminated film for evaluation prepared by the above method, a 120mm × 120 mm-sized pouch was prepared, and a 0.3% ethyl maltol aqueous solution (simulated food) as a content was prepared and filled with 50 g. For the fabricated pouches, retort sterilization treatment was performed at 121 ℃ for 30 minutes. Thereafter, the packaging bag was stored in a thermostatic bath at 80 ℃ to visually evaluate the film appearance after 1 day.

3-3. commercial food blended with Ethyl maltol (resistance test appearance after 1 week at 80 ℃ C.)

From the laminated film for evaluation produced by the above method, a 120mm × 120 mm-sized pouch was produced as a content, and a commercially available food mixed with ethyl maltol was changed to the above-sized pouch, and the retort-sterilized packaging bag was stored in a thermostatic bath at 80 ℃, and the film appearance after 1 week was visually evaluated.

3-4 commercial food blended with Ethyl maltol (resistance test appearance after 3 weeks at 80 ℃ C.)

From the laminated film for evaluation produced by the above method, a 120mm × 120 mm-sized pouch was produced as a content, and a commercially available food mixed with ethyl maltol was changed to the above-sized pouch, and the retort-sterilized packaging bag was stored in a thermostatic bath at 80 ℃, and the film appearance after 3 weeks was visually evaluated.

3-5 commercial food blended with Ethyl maltol (resistance test appearance after 4 weeks at 80 ℃ C.)

From the laminated film for evaluation produced by the above method, a 120mm × 120 mm-sized pouch was produced as a content, and a commercially available food mixed with ethyl maltol was converted into the above-sized pouch, and the retort-sterilized packaging bag was stored in a thermostatic bath at 80 ℃, and the film appearance after 4 weeks was visually evaluated.

Any visual evaluation is the following criteria.

O: no change in appearance

And (delta): between the aluminum foil/CPP film, a portion was layered.

X: and layering between the aluminum foil/CPP films.

TABLE 1

TABLE 2

As a result, the laminated film using the reactive adhesive obtained in example satisfied all the evaluation properties. In particular, in example 3 in which pyromellitic anhydride and 3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furyl) -1, 3-isobenzofurandione were used in combination, or in example 4 in which pyromellitic anhydride and gallic acid were used in combination, the resistance test of the ethyl maltol solution was good even after 4 weeks. On the other hand, the comparative example does not contain pyromellitic anhydride, and fails to satisfy all the evaluation properties.

Claims

1. A reactive adhesive comprising a polyisocyanate composition (X), a polyol composition (Y) and pyromellitic anhydride, wherein the pyromellitic anhydride is contained in an amount of 0.2 to 2.0 wt% based on the total solid content of the reactive adhesive.

2. The reactive adhesive according to claim 1, which contains 3a, 4, 5, 7 a-tetrahydro-7-methyl-5- (tetrahydro-2, 5-dioxo-3-furanyl) -1, 3-isobenzofurandione, or gallic acid.

3. The reactive adhesive according to claim 1 or 2, wherein the polyol composition (Y) is at least one or more polyols selected from the group consisting of polyester polyols, polyurethane polyols, polyether polyols, polyester polyurethane polyols, and polyether polyurethane polyols.

4. A laminated film comprising a first plastic film and a second plastic film laminated therebetween with an adhesive layer comprising the reactive adhesive according to any one of claims 1 to 3.

5. A packaged article formed by molding a laminated film in the form of a bag, the laminated film being formed by laminating an adhesive layer between a first plastic film and a second plastic film, the adhesive layer being the layer of the reactive adhesive according to any one of claims 1 to 3.