Laminate

Abstract

To provide a laminate that exhibits excellent fragrance retention regardless of the type of fragrance, as well as superior adhesion and lamination strength. [Solution] A laminate having, in this order, a base layer, a layer formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a curing agent, an adhesive layer, and a sealant layer.

Description

[Technical Field]

[0001] The present invention relates to laminates used for packaging alcoholic beverages, flavored beverages, coffee powder, fragrance powder, fabric softeners, liquid detergents, shampoos, conditioners, perfumes, and other beverages and foods containing fragrance components, as well as detergents and cosmetics. [Background technology]

[0002] For packaging beverages, foods, detergents, and cosmetics containing aromatic components such as alcoholic beverages, flavored beverages, coffee powder, fragrance powder, fabric softeners, liquid detergents, shampoos, conditioners, and perfumes, films with high fragrance retention properties (such as films laminated with highly barrier-type polyvinyl alcohol resin or ethylene-vinyl alcohol copolymer resin) have been used to prevent the fragrance from escaping the container. While the tendency of such films to prevent the permeation of fragrance components and maintain their properties seems related to their gas barrier properties, these tendencies do not always coincide in reality.

[0003] Furthermore, packaging materials that retain fragrance are known to consist of a resin film with a metal layer or a metal oxide layer. However, the metal foil layer or metal oxide layer contained in both types of packaging is not resin, and when they are collected and reused, it takes extra effort to separate the different materials. Furthermore, if items containing a large amount of aromatic compounds are stored in containers with insufficient fragrance retention, even if they are airtight, the aromatic compounds will leak out of the container over time. As a result, when aromatic compounds leak from products in a store with a large number of items on display, even if only a small amount of aromatic compounds permeates from one product, the total amount of leakage is large, and as a result, the entire sales floor becomes filled with fragrance.

[0004] Patent documents 1 and 2 describe polyester polyols that have low oxygen permeability, but whose permeability to fragrance components is unknown. Patent Document 3 describes a laminate for liquid packaging that has low oxygen permeability and excellent aroma retention, achieved by combining a specific heat-seal layer, a coating layer, and an adhesive layer. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 7207617 [Patent Document 2] Patent No. 7529179 [Patent Document 3] International Publication No. 2024 / 135510 [Overview of the project] [Problems that the invention aims to solve]

[0006] This invention has been made in view of the above circumstances, and aims to provide a laminate that has excellent lamination strength and excellent fragrance retention regardless of the type of fragrance. [Means for solving the problem]

[0007] The inventors of the present invention have conducted extensive research to solve the above problems and have found that the above problems can be solved by using the laminate shown below, thereby completing the present invention. 1. A laminate comprising, in this order, a base layer, a layer formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a curing agent, an adhesive layer, and a sealant layer. 2. The laminate according to claim 1, having a printed layer between the layer formed by curing an unsaturated polyester resin having a glass transition temperature of 35°C or higher with a curing agent and the adhesive layer. 3. The laminate according to claim 1 or 2, wherein the unsaturated polyester resin having a glass transition temperature of 35°C or higher is an unsaturated polyester resin containing structural units derived from fumaric acid and / or maleic acid. 4. The dry coating amount of the layer formed by curing the unsaturated polyester resin having a glass transition temperature of 35°C or higher with a curing agent is 0.05 to 5.0 g / m². 2 A laminate as described in any of 1 to 3. 5. A laminate for packaging films having a layer on top of a sealant layer, the layer being formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a curing agent. 6. A coating composition containing an unsaturated polyester resin having a glass transition temperature of 35°C or higher and a curing agent. [Effects of the Invention]

[0008] According to the present invention, a laminate exhibiting excellent aroma retention can be obtained. [Modes for carrying out the invention]

[0009] The present invention is based on a laminate comprising, in order, a base layer, a layer (fragrance-retaining layer) formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a curing agent, an adhesive layer, and a sealant layer. The aroma retention property in this invention is different from so-called gas barrier properties. Aroma retention is the property of preventing aroma components from leaking out of the container without allowing them to permeate, while gas barrier properties typically target carbon dioxide, oxygen, and sometimes water vapor, preventing their intrusion from outside the container and their volatilization to the outside of the container. Since aroma retention and gas barrier properties prevent the permeation of different gaseous components, a layer that simply has gas barrier properties cannot be said to have aroma retention properties. The present invention will be described below. Furthermore, a layer formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a curing agent is sometimes simply referred to as a "fragrance-retaining layer." Similarly, a layer formed by curing with a curing agent is sometimes simply referred to as a "cured layer." A coating agent composition that forms a layer formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher is sometimes simply referred to as a "fragrance-retaining coating composition," including cases where the unsaturated polyester resin layer with a glass transition temperature of 35°C or higher is cured with a curing agent as needed.

[0010] The hydroxyl value of polyester resins as used herein is defined as follows: The hydroxyl value of the polyester resin can be determined by applying the method specified in JIS K1557-1:2007. That is, after acetylating the hydroxyl groups by dissolving the polyester resin, which is the sample, in a pyridine solution containing an acetylating reagent (for example, acetic anhydride), the excess acetylating reagent is hydrolyzed with water, and the amount of acetic acid produced is determined by titration with potassium hydroxide. At this time, since the carboxyl groups contained in the polyester resin are also titrated with potassium hydroxide, the hydroxyl value (mgKOH / g) is calculated by subtracting the acid value of the polyester resin from the above titration result.

[0011] The glass transition temperature of the polyester resin in this specification is defined as follows. The glass transition temperature of the polyester resin is the measured glass transition temperature determined by thermal analysis. As a method of thermal analysis, in accordance with JIS K7121 (Method for Measuring Transition Temperature of Plastics), for example, using Pyris1 DSC manufactured by PerkinElmer, the glass transition temperature can be measured under the conditions of a heating rate of 20 °C / min and a nitrogen gas flow rate of 20 milliliters / min.

[0012] The unsaturated polycarboxylic acid content of the unsaturated polyester resin in this specification is defined as follows. The molar ratio of the unsaturated aliphatic polycarboxylic acid component in all the polycarboxylic acid components constituting the unsaturated polyester resin.

[0013] <Amine value of the binder resin in the printing layer> The amine value of the binder resin in the printing layer means the amine value per 1 g of solid content, and after measurement by the potentiometric titration method (for example, COMTITE (AUTO TITRATOR COM-900, BURET B-900, TITSTATION K-900), manufactured by Hiranuma Sangyo Co., Ltd.) using a 0.1N hydrochloric acid aqueous solution, it refers to the value converted to the equivalent of potassium hydroxide.

[0014] <Base material layer> As the base material layer used in the laminate of the present invention, a known one may be used. A layer formed by curing an unsaturated polyester resin having a glass transition temperature of 35°C or higher is provided. On the printing layer provided as needed, a sealant layer is provided via an adhesive layer or the like. As a packaging material for foods, daily necessities, etc. having a fragrance component, it may be used as a layer located on the outermost layer side of the packaging container in a state where these are packaged. As the base material layer, polyolefins such as polyethylene, polypropylene, and ethylene-propylene copolymer, polyesters such as polyethylene terephthalate, unstretched films such as polyamide, uniaxially stretched resin films and biaxially stretched resin films such as polyolefins such as polyethylene and polypropylene, paper, woven fabrics or non-woven fabrics within the range where a printing layer can be formed, can be selected and used. Among them, uniaxially stretched resin films and biaxially stretched resin films are preferable. Moreover, a laminate of a plurality of these layers may be used as the base material layer, and corona discharge treatment or primer treatment may be performed in advance on the surface of the base material layer on the side where the fragrance retention layer is formed to improve the adhesion with the fragrance retention layer.

[0015] <Unsaturated polyester resin layer with a glass transition temperature of 35°C or higher> The layer formed by curing the unsaturated polyester resin having a glass transition temperature of 35°C or higher in the present invention is a fragrance retention layer. This fragrance retention layer may be a layer formed by applying a coating composition containing an unsaturated polyester resin having a glass transition temperature of 35°C or higher and a curing agent under normal conditions and then drying and / or curing. Also, an unsaturated polyester resin having a glass transition temperature of 35°C or higher and a curing agent may be reacted in advance, and a layer formed by applying and drying a fragrance retention coating composition containing this reaction product may also be used. In the present invention, by adopting an unsaturated polyester resin having a glass transition temperature of 35°C or higher, the formed resin layer has better adhesion with an adjacent layer than when using other resins.

[0016] (Unsaturated polyester resin) In the present invention, one or more unsaturated polyester resins having a glass transition temperature of 35°C or higher are used. The unsaturated polyester resin having a glass transition temperature of 35°C or higher in this invention is a condensate of the following low molecular weight polyol compound and / or high molecular weight polyol compound polyol compound, the following unsaturated aliphatic polycarboxylic acid, and a saturated aliphatic polycarboxylic acid and / or aromatic polycarboxylic acid. The glass transition temperature of the unsaturated polyester resin is 35°C or higher, preferably 40°C or higher, more preferably 50°C or higher, even more preferably 55°C or higher, and most preferably 60°C or higher. If the temperature is below 35°C, the aroma retention of the resulting laminate will decrease. In the present invention, the unsaturated polyester resin having a glass transition temperature of 35°C or higher preferably has a number-average molecular weight of 2,000 to 100,000. The unsaturated polycarboxylic acid content in the total polycarboxylic acid components of the unsaturated polyester resin is preferably 3.0% or more, more preferably 15.0% or more, even more preferably 25.0% or more, preferably 100% or less, more preferably 85.0% or less, and even more preferably 75.0% or less, in terms of molar ratio. Furthermore, 3.0 to 70% is preferred. Furthermore, it may or may not have hydroxyl groups. If it has hydroxyl groups, the hydroxyl value is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, and even more preferably 20 mg KOH / g or more. Alternatively, it is preferably 200 mg KOH / g or less, more preferably 100 mg KOH / g or less, and even more preferably 50 mg KOH / g or less.

[0017] (Low molecular weight polyols) The low molecular weight polyols mentioned above are not particularly limited, and when using low molecular weight polyols, one or more can be selected from the following aliphatic diols, alicyclic diols, aromatic diols, and polyols with three or more functions. Aliphatic diols and alicyclic diols include ethylene glycol, diethylene glycol, 1,2-propanediol, 1,3-propanediol, tripropylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, neopentyl glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 2-methyl-1,3-propanediol, 1,4-pentanediol, 3-methyl-1,5-pentanediol, 2, Low molecular weight diols with or without branched structures such as 5-hexanediol, 2-methyl-1,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2,2,4-trimethyl-1,3-pentanediol, 2,2,4-trimethyl-1,6-hexanediol, cyclohexanedimethanol, tricyclodecanedimethanol, and hydrogenated alicyclic compounds of the following aromatic diols.

[0018] Aromatic diols include hydroquinone, resorcinol, catechol, naphthalenediol, biphenol, bisphenol A, bisphenol F, and tetramethylbiphenol. Examples of polyols with three or more functionalities include glycerin, trimethylolpropane, trimethylolethane, tris(2-hydroxyethyl) isocyanurate, 1,2,4-butanetriol, pentaerythritol, and dipentaerythritol.

[0019] (Polymer polyol) The above-mentioned polymeric polyol is not particularly limited, and when using a polymeric polyol, one or more compounds from the following can be selected and used. Polyether diol compounds such as polyalkylene glycols including polyethylene glycol and polypropylene glycol, ethylene oxide extensions including bisphenol A, bisphenol F, and tetramethylbiphenol, alkylene oxide adducts including propylene oxide, and polyester polyols obtained by condensing one or more of the following polycarboxylic acids such as adipic acid, sebacic acid, and phthalic anhydride with one or more of the above low molecular weight polyols such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, and glycerin.

[0020] (Unsaturated aliphatic polycarboxylic acids that can react with the above polyol compounds) The above-mentioned unsaturated aliphatic polycarboxylic acid is not particularly limited. When using an unsaturated aliphatic polycarboxylic acid, one or more of the following compounds and their acid anhydrides or halides can be selected and used. Unsaturated linear aliphatic dicarboxylic acid compounds and their derivatives, such as maleic acid, fumaric acid, itaconic acid, citraconic acid, mesaconic acid, aconitic acid, and their acid anhydrides and halides; and unsaturated alicyclic polycarboxylic acid compounds and their derivatives, such as cyclohexenedicarboxylic acid, cycloheptenedicarboxylic acid, bicycloheptenedicarboxylic acid, and methyltetrahydrophthalic acid. Among the above, one or more selected from fumaric acid, maleic acid, and their acid anhydrides are preferred.

[0021] (Saturated aliphatic polycarboxylic acids that may be used in combination with unsaturated aliphatic polycarboxylic acid compounds) The saturated aliphatic polycarboxylic acid is not particularly limited, and when using a saturated aliphatic polycarboxylic acid, one or more of the following compounds and their acid anhydrides or halides can be selected and used. Aliphatic dibasic acids and aromatic dibasic acids such as adipic acid, succinic acid, sebacic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, superiric acid, azelaic acid, 1,2-hexahydrophthalic acid, 1,1-cyclobutanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid (cis- or trans-1,4-cyclohexanedicarboxylic acid), or derivatives thereof, etc.

[0022] (Aromatic polycarboxylic acid compounds that may be used in combination with unsaturated aliphatic polycarboxylic acid compounds) The above-mentioned aromatic polycarboxylic acid compounds are not particularly limited, and when using aromatic polycarboxylic acid compounds, one or more of the following compounds and their acid anhydrides or halides can be selected and used. Aromatic aliphatic polycarboxylic acid compounds such as phthalates (orthophthalic acid, isophthalic acid, terephthalic acid), trimellitic acid, pyromellitic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, trimellitic acid, and pyromellitic acid.

[0023] The unsaturated polyester resin does not necessarily have to be a polyester polyol having an isocyanuric ring; a polycarboxylic acid having three or more carboxylic acid groups in its molecule may also be used in combination. To obtain an unsaturated polyester resin by reacting the above polyol compound with a polycarboxylic acid, these are reacted in the presence of a catalyst. For this type of catalyst, commonly used catalysts for the reaction between polyol compounds and polycarboxylic acids can be employed.

[0024] (Hardening agent) As a curing agent that reacts with the unsaturated polyester resin, or a curing agent that reacts with the unsaturated polyester resin beforehand, a polyisocyanate curing agent (polyisocyanate compound) can be used in the fragrance-retaining coating composition. Examples of polyisocyanate compounds include aromatic aliphatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates. Among these, isocyanate curing agents with three or more functionalities are preferred. Furthermore, the laminate of the present invention may or may not contain residual unreacted curing agent in the aroma-retaining layer after curing. By using this curing agent in the present invention, the fragrance retention can be improved.

[0025] Specific examples of aromatic aliphatic diisocyanates include 1,3- and / or 1,4-phenylenediisocyanate, 4,4-diisocyanatobiphenyl, 3,3-dimethyl-4,4-diisocyanatobiphenyl, 1,3- or 1,4-xylylenediisocyanate, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene or mixtures thereof, ω,ω'-diisocyanato-1,4-diethylbenzene, α,α,α',α'-tetramethylxylylenediisocyanate, and the like.

[0026] Specific examples of aliphatic diisocyanates include 1,6-hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, lysine diisocyanate, and trioxyethylene diisocyanate. Specific examples of alicyclic diisocyanates include isophorone diisocyanate, cyclohexane diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated tetramethylxylene diisocyanate. Furthermore, it is acceptable to use a mixture of two or more such isocyanate compounds.

[0027] Furthermore, it is preferable to use components such as adducts obtained by reacting the above polyisocyanate compound with low molecular weight active hydrogen compounds such as ethylene glycol, propylene glycol, metaxylylene alcohol, 1,3-bishydroxyethylbenzene, 1,4-bishydroxyethylbenzene, trimethylolpropane, glycerol, pentaerythritol, erythritol, sorbitol, ethylenediamine, monoethanolamine, diethanolamine, triethanolamine, and metaxylylenediamine, and their alkylene oxide adducts, various polyester resins, polyether polyols, and high molecular weight active hydrogen compounds such as polyamides, biuret compounds obtained by trimerizing the above diisocyanate compound, and isocyanurate compounds obtained by isocyanurating the above diisocyanate compound. In particular, one or more selected from XDI-TMP adduct (trimethylolpropane adduct of xylylene diisocyanate), HDI-biuret (trimer of hexamethylene diisocyanate), and IPDI-isocyanurate (trimer of isophorone diisocyanate) are preferred.

[0028] From an environmental perspective, a biomass curing agent containing both a biomass polyol compound and a biomass polyisocyanate compound is preferred. However, a non-biomass curing agent is also acceptable. As a biomass curing agent, a trifunctional isocyanate compound having an isocyanurate ring obtained by isocyanurating biomass diisocyanate may also be used. Biomass isocyanates can also be obtained by using plant-derived amino acids as raw materials and converting their amino groups to isocyanate groups. For example, lysine diisocyanate (LDI) is obtained by methyl esterifying the carboxyl group of lysine and then converting the amino group to an isocyanate group. Similarly, 1,5-pentamethylene diisocyanate is obtained by decarboxylating the carboxyl group of lysine and then converting the amino group to an isocyanate group. Polymers or oligomers obtained by polymerizing the above isocyanate compounds and diol compounds so that the terminal ends are isocyanate groups can also be used. As a trifunctional isocyanate compound having an isocyanurate ring, a trifunctional isocyanate compound having an isocyanurate ring obtained by isocyanurating an isocyanate having two isocyanate groups in the molecule can be used. The chemical equivalent ratio of the hydroxyl groups of the polyol compound to the isocyanate groups of the polyisocyanate compound in the curing agent (isocyanate groups of the polyisocyanate compound) / (hydroxyl groups of the polyol compound) is preferably 100% to 500%.

[0029] (solvent) The solvent used in the fragrance-retaining coating composition containing an unsaturated polyester resin with a glass transition temperature of 35°C or higher and a curing agent may be an organic solvent and / or water, but one with a low boiling point is preferred. Examples of organic solvents include toluene, ketone-based organic solvents (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ester-based solvents (e.g., methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, isobutyl acetate, etc.), alcohol-based solvents (e.g., methanol, ethanol, n-propanol, isopropanol, butanol, etc.), and hydrocarbon-based solvents (e.g., toluene, methylcyclohexane, etc.). To reduce residual solvent, ketone-based organic solvents (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.) and ester-based organic solvents (e.g., ethyl acetate, etc.) are preferred. Since the laminate of the present invention has a fragrance-retaining layer formed from a fragrance-retaining coating composition between the base layer and the adhesive layer, even when it is used as a container, residual solvent does not pass through the base layer or sealant layer, nor does it diffuse the residual solvent outside the container or cause the contents inside the container to emit the odor of the residual solvent.

[0030] (Other ingredients) Other components that the fragrance-retaining coating composition may contain, to the extent that they do not impair the effects of the present invention, include hydroxyl group-containing polyester resins other than unsaturated polyester resins and other polyol compounds. It may also contain pigments such as known extender pigments and coloring pigments, pigment dispersants, dyes, and the like.

[0031] Furthermore, a catalyst can be used during the reaction between the polyester polyol and the isocyanate curing agent. Among these, organometallic compounds are preferred, and such organometallic compounds include titanium compounds such as dibutyltitanium dichloride, tetrabutyltitanate, and butoxytitanium trichloride, as well as dibutyltin sulfide, tributyltin sulfide, tributyltin oxide, dibutyltin dichloride, dibutyltin oxide, dibutyltin dibromide, dibutyltin dimaleate, dibutyltin dilaurate, dibutyltin diacetate, dioctyltin dilaurate, and tributyltin dichloromide. Examples include tin acetate, tributyltin chloride, triethyltin ethoxide, tributyltin ethoxide, dioctyltin oxide, tributyltin trichloroacetate, and tin 2-ethylhexanoate; lead compounds such as lead oleate, lead 2-ethylhexanoate, lead benzoate, and lead naphthenate; and iron 2-ethylhexanoate, iron acetylacetonate, cobalt benzoate, cobalt 2-ethylhexanoate, zinc naphthenate, zinc 2-ethylhexanoate, and zirconium naphthenate. Among these, titanium compounds such as tetrabutyl titanate are preferred. Tertiary amine compounds can also be used, for example, triethylamine, triethylenediamine, 1,4-diazabicyclo(2,2,2)octane, and 1,8-diazabicyclo(5,4,0)-undecene-7 (DBU).

[0032] <Method for forming a layer formed by curing an unsaturated polyester resin having a glass transition temperature of 35°C or higher> The fragrance-retaining layer in the present invention can be formed on the base material layer by known means using the above fragrance-retaining coating composition. The above-known means include roll coating methods using a gravure cylinder or the like, doctor knife methods, air knife / nozzle coating methods, bar coating methods, spray coating methods, dip coating methods, and coating methods combining these methods.

[0033] The dry coating amount (coating amount after drying) of the fragrance-retaining layer in the laminate of the present invention varies depending on the thickness and material of the above base material layer and the target fragrance-retaining level, but is preferably 0.05 to 5.0 g / m 2 is preferred. Also, from the viewpoint of reducing the residual solvent in the fragrance-retaining layer and obtaining appropriate fragrance retention, it is preferably 1.5 g / m 2 or less. When the coating amount is less than 0.05 g / m 2 , it may not be possible to obtain the target fragrance retention. Even if it exceeds 5.0 g / m 2 , it is difficult to further improve the fragrance retention, and moreover, a large amount of residual solvent derived from the components of the fragrance-retaining coating composition may remain in the fragrance-retaining layer. Preferably it is 0.05 g / m 2 or more, and more preferably 0.08 g / m 2 or more. The laminate of the present invention has sufficient fragrance retention even when the coating amount of the solid content of the fragrance-retaining layer is 0.05 to 1.5 g / m 2 , and further 0.05 to 1.0 g / m 2 and is a very thin layer.

[0034] (Sealant layer) The sealant layer can be a known sealant layer, and examples include polyolefins such as uniaxially oriented polyethylene, uniaxially oriented polypropylene, biaxially oriented polyethylene, biaxially oriented polypropylene, unoriented polyethylene, and unoriented polypropylene, ethylene-vinyl acetate copolymers, and films for dry lamination.

[0035] <Print layer> In the present invention, a printing layer may or may not be provided between the layer formed by curing a specific unsaturated polyester resin, which is the fragrance-retaining layer, and the adhesive layer, or between the substrate layer and the fragrance-retaining layer. The printing layer is formed by printing a printing ink composition containing a pigment, a binder resin, and a solvent, and drying and / or curing it under normal conditions, and is a layer having a pigment and a binder resin. The printing ink composition is not limited as long as it can exhibit the effects of the present invention, but it is preferable to use a printing ink composition for flexible packaging lamination. When a printed layer is provided between the base layer and the fragrance-retaining layer, a laminate for packaging film may be prepared in advance on top of the sealant layer, having a layer made of unsaturated polyester resin with a glass transition temperature of 35°C or higher that has been cured with a curing agent. The surface of this cured layer may then be laminated together with the surface of the printed layer of the pre-formed laminate of the base layer and printed layer. When a packaging container is made using the laminate of the present invention, the printed layer is a layer that can be seen from the outer surface of the packaging container through the base material layer. The printed layer consists of one or more layers on all or part of its surface. It is not necessary for the printed layer to be formed on the entire surface of the base material layer. In this case, the adhesive layer can be seen directly from the base material layer side. In the present invention, a printed layer formed using a printing ink composition for flexible packaging lamination will be specifically described as an example.

[0036] (Pigment) As the above-mentioned pigments, for example, various inorganic pigments, organic pigments, or extender pigments commonly used in printing inks can be used. As the inorganic pigments mentioned above, colored pigments such as titanium dioxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, Prussian blue, ultramarine, carbon black, and graphite can be used. Examples of the above-mentioned organic pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, and condensed polycyclic pigments. Examples of extender pigments include silica particles, calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, and talc. Among these, titanium dioxide is preferred as the white pigment. The content of these pigments in printing ink compositions for flexible packaging laminations is typically around 1 to 50% by mass. Furthermore, a pigment dispersant may be used in combination. Examples of such pigment dispersants include polyester-based pigment dispersants that can be used in gravure printing ink compositions containing organic solvents. Specifically, examples include Azisper PB821, PB822, PB824, PB881 (manufactured by Ajinomoto Fine Techno Co., Ltd.), Solspers 24000, 56000 (manufactured by Nippon Lubrizol Co., Ltd.), and among these, basic group-containing polyester-based polymer dispersants can be preferably used. When including a pigment dispersant, the amount is usually preferably 1 to 200 parts by mass, and more preferably 1 to 60 parts by mass, per 100 parts by mass of the total pigment.

[0037] (Binder resin) The binder resin in the printed layer preferably contains amino groups and hydroxyl groups to ensure excellent adhesion to the substrate layer. The amine value is preferably 1.00 to 13.00 mgKOH / g, and the hydroxyl value is preferably 0.50 to 12.00 mgKOH / g. A hydroxyl group-containing polyurethane resin with amino groups at its ends is preferred as such a binder resin. From an environmental perspective, it is preferable that the polyurethane resin be a biomass polyurethane resin. Furthermore, one of the following may be used as the binder resin: a vinyl chloride / vinyl acetate copolymer resin having hydroxyl groups, a vinyl chloride / acrylic copolymer resin having hydroxyl groups, or a cellulose resin. The printing ink composition for flexible packaging lamination used to form the printed layer in the present invention preferably contains one or more selected from adhesion improvers and blocking inhibitors, preferably an adhesion improver and a blocking inhibitor, to the extent that it does not degrade the performance targeted by the present invention.

[0038] (Adhesion enhancer) As adhesion enhancers, rosin and its derivatives, chlorinated polypropylene, dammar resin, etc., can be used. (Blocking prevention agent) As anti-blocking agents, silica particles, polyethylene wax, fatty acid amides, etc., can be used.

[0039] (solvent) (Organic solvents) Among the solvents used in the above-mentioned printing ink composition for flexible packaging lamination, various organic solvents can be used, such as ketone-based organic solvents like acetone, methyl ethyl ketone, and methyl isobutyl ketone; ester-based organic solvents like methyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, and isobutyl acetate; alcohol-based organic solvents like methanol, ethanol, n-propanol, isopropanol, and butanol; and hydrocarbon-based solvents like toluene and methylcyclohexane. From an environmental perspective, it is preferable to use a mixed solvent of ester-based organic solvents, alcohol-based organic solvents, and ketone-based organic solvents, or a mixed solvent of ester-based organic solvents and alcohol-based organic solvents that are more environmentally friendly. From a monosolvent perspective, it is even more preferable not to use alcohol. (water) The solvent used in the above-mentioned printing ink composition for flexible packaging lamination preferably contains water to mitigate printing defects caused by static electricity, prevent plate overhang, and improve cell reproducibility. When water is included, the content in the printing ink composition for packaging lamination is preferably 10.0% by mass or less, and more preferably 0.1 to 5.0% by mass.

[0040] (Other materials that may be contained in the printing layer and methods for manufacturing printing ink compositions for packaging lamination) The printing ink composition for packaging lamination used to form the printed layer in the present invention may further contain various additives such as antistatic agents and plasticizers. Known methods can be used to produce such printing ink compositions for packaging lamination. Specifically, for example, a mixture of pigment, binder resin, organic solvent, and optionally a pigment dispersant can be kneaded using a high-speed mixer, ball mill, sand mill, attritor, etc., and then the remaining materials, such as predetermined additives, can be added and mixed.

[0041] (Method for forming the printed layer) The method for forming a printed layer according to the present invention will be described. For example, a substrate such as a resin film is printed once or more times using a gravure printing method with a packaging laminate printing ink composition other than white. Then, on the non-white printed layer formed by this printing (on the opposite side of the substrate layer from the perspective of the printed layer (the side on which the sealant layer will be formed thereafter)), a white packaging laminate printing ink composition is printed once or more times using a gravure printing method to obtain the printed layer according to the present invention. Note that only one of the non-white printed layer and the white printed layer may be formed. The substrate such as a resin film may be the resin film itself or a resin film whose surface has been treated with a known treatment.

[0042] <Adhesive layer> The adhesive layer is formed between the printed layer or the layer formed by curing unsaturated polyester resin and the sealant layer, and has the function of making these layers adhere tightly to each other. The adhesive used to form such an adhesive layer is not particularly limited as long as it performs the functions described above. The adhesive layer is formed by known means, such as applying an adhesive composition onto the printed layer, and is obtained by curing as necessary. In particular, a layer formed from a two-component curing polyurethane resin adhesive is preferred because it exhibits an even better balance between adhesion and the overall fragrance retention of the laminate. Especially, using an adhesive containing a polyol compound and a polyisocyanate compound, and having the adhesive layer contain a reaction product of the polyol compound and polyisocyanate compound, is preferable for further enhancing this effect. From an environmental perspective, a two-component, curable biomass polyurethane resin-based adhesive is more preferable as the adhesive composition. To obtain particularly good adhesion, adhesive compositions used in dry lamination may be used.

[0043] (Polyol compounds) The polyol compound contained in the aforementioned two-component curable polyurethane resin adhesive is preferably a polyol component that is an aromatic polyol, aliphatic polyol, aliphatic polyester, or aliphatic polyester compound having at least two hydroxyl groups in its molecule. Examples of such polyol components include aromatic or aliphatic polyurethane polyols, polyester polyols, polyether polyols, and acrylic polyols, and two or more of these polyol components may be mixed and used. Among these, aromatic or aliphatic polyurethane polyols, polyester polyols, and polyether polyols are preferred because their glass transition temperature and storage modulus are easily controlled. From an environmental perspective, biomass polyol components are preferred as polyol components. Particularly preferred are biomass polyether polyols and biomass polyester polyols.

[0044] (Polyisocyanate compounds) Similarly, the polyisocyanate compound is preferably a polyisocyanate compound having at least two or more isocyanate groups in its molecule. Examples of such polyisocyanate compounds include aromatic aliphatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates, and two or more such polyisocyanate compounds may be used in mixture form. Examples of aromatic aliphatic diisocyanates include 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, 1,3- or 1,4-bis(1-isocyanato-1-methylethyl)benzene or mixtures thereof, ω,ω'-diisocyanato-1,4-diethylbenzene, and the like.

[0045] Examples of aliphatic diisocyanates include hexamethylene diisocyanate, tetramethylene diisocyanate, 2-methylpentane-1,5-diisocyanate, 3-methylpentane-1,5-diisocyanate, lysine diisocyanate, and trioxyethylene diisocyanate. Examples of alicyclic diisocyanates include isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated diphenylmethane diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated tetramethylxylene diisocyanate. Furthermore, two or more of these polyisocyanate compounds may be used in combination. It is also preferable to use an isocyanate component with three or more functionalities.

[0046] Examples of adhesive compositions used in dry lamination include DIC Dry LX-401A, 75A, 719, 703VL, 500, 510, etc. (manufactured by DIC Graphics, DIC Dry is a registered trademark of DIC Graphics), Takelac / Takenate A-969 / A-5, A-909 / A-5, A-977 / A-92, A-606 / A-50, A-515 / A-50, A-626 / A-50, A-525 / A-52, A-666 / A-65, etc. (manufactured by Mitsui Chemicals, Inc.), and RU-77, 771, 3600, 3900, etc. (manufactured by Rock Paint Co., Ltd.). Furthermore, from an environmental and safety standpoint, it is preferable to use biomass polyol compounds and biomass polyisocyanate compounds for the above-mentioned polyol compounds and polyisocyanate compounds.

[0047] (Sealant layer) The sealant layer can be a known sealant layer, and examples include polyolefins such as uniaxially oriented polyethylene, uniaxially oriented polypropylene, biaxially oriented polyethylene, biaxially oriented polypropylene, unoriented polyethylene, and unoriented polypropylene, ethylene-vinyl acetate copolymers, and films for dry lamination.

[0048] <Laminate> To obtain the laminate of the present invention, the fragrance-retaining coating composition is applied to a substrate and dried as described above. Then, a printed layer is optionally formed by any means, an adhesive layer is provided thereon, and then a sealant layer is dry-laminated by a conventional method. Alternatively, the packaging film laminate may be obtained by laminating the polyester resin side of a laminate having a layer of unsaturated polyester resin with a glass transition temperature of 35°C or higher, which has been cured with a curing agent, onto the sealant layer.

[0049] (Other functional layers) Furthermore, the laminate of the present invention may or may not have one or more functional layers between the base layer and the sealant film, provided that such layers do not impair the effects of the present invention, for the purpose of improving gas barrier properties or reinforcing strength. Examples of such functional layers include vapor-deposited layers or inorganic thin films of silica, alumina, or metal, or other resin layers, for the purpose of improving gas barrier properties such as oxygen; stretched nylon film layers for the purpose of reinforcing the strength of the laminated film; and nylon-based metaxylenediamine resin film layers for the purpose of improving both of the above functions. These various functional layers can be formed by vapor deposition onto any layer such as a substrate layer or sealant layer, by forming a coating film, or by laminating films. The laminate of the present invention may or may not have a layer made of ethylene-vinyl alcohol copolymer, polyvinyl alcohol, or polyamide, an inorganic compound layer such as a metal layer or a metal oxide layer, or a layer containing a metal-containing pigment. Furthermore, a desorption layer may be provided in any of the layers in the present invention. By providing a desorption layer, the laminate can be broken down into smaller pieces after use and decomposed by immersing it in water with a basic solution, etc.

[0050] (Applications of the laminate of the present invention) The laminate of the present invention, comprising a base layer, a layer of unsaturated polyester resin that has hardened to retain fragrance, a printing layer, an adhesive layer, and a sealant layer in that order, is exclusively for packaging films, and in particular for containers such as bags that airtightly package solid or liquid items containing fragrance components, such as foods that naturally contain fragrance components, foods with added fragrances, cosmetics, detergents, shampoos, and conditioners. To achieve this, the sealant layers of the laminate are pressed together by heating or other means to seal the packaged items and prevent the fragrance components from being released outside the container. Therefore, when the laminate of the present invention is used in a container that can be airtightly sealed, it is possible to prevent the fragrance from leaking out of the container by allowing the fragrance components to penetrate or permeate at least the laminate of the present invention.

[0051] If necessary, the laminate can be provided with another layer to prevent the permeation of, for example, oxygen, carbon dioxide, or water, thereby achieving both the prevention of fragrance component permeation and the prevention of oxygen, carbon dioxide, and water permeation as a whole. It may also have a layer to block ultraviolet rays. Laminates having these layers may be protected, sealed, and packaged to protect the contents without having a metal layer or metal oxide layer. Furthermore, it can be used to package contents that previously required a metal layer or similar to prevent the permeation of fragrance components. The form of the container using the laminate of the present invention is not particularly limited. The laminate of the present invention may be used for the entire container, or it can be used as a component such as a lid or seal that adheres tightly to the container body having aroma-retaining properties, such as a bag, glass container, or resin injection molded or extruded product.

[0052] (Fragrance components) The fragrance components whose permeation is prevented by the layer formed by the fragrance-retaining coating composition of the present invention are the fragrance components contained in the above-mentioned solids or liquids that are packaged in containers formed using the packaging material having this layer. Such fragrance components include fragrance components derived from raw materials used to obtain the solid or liquid (for example, if the solid or liquid is a food product, these may include spices, meat, vegetables, fruits, fish, dairy products, seasonings, oils, etc.), as well as natural and synthetic fragrance components added during the manufacturing of products such as food products, fabric softeners, liquid detergents, shampoos, conditioners, antiperspirants, wet wipes, cosmetics, air fresheners for rooms and cars, and scented stationery, for the purpose of adding fragrance. Furthermore, the definition is not limited to the fragrance components of these items. Furthermore, preventing the permeation of aromatic components does not necessarily mean preventing the permeation of substances other than aromatic components, such as oxygen and nitrogen. [Examples]

[0053] <Fabrication of laminates> (Examples 1-9, 10-1, 11-1-11-4) Coating agent compositions with the compositions shown in Examples 1-9 and Comparative Examples 1-3 were obtained to achieve the compositions shown in Table 1. Using these coating agent compositions, laminates were obtained by the following method to have the layer structure of base layer OPP / fragrance-retaining layer / adhesive layer / sealant layer CPP as shown in Example 10-1 in Table 2. These results are shown in Table 1. Example 10-1 in Table 2 and Example 11-1 in Table 3 are the same laminates as Example 1. Examples 11-2 to 11-4 in Table 3 are examples in which the amount of fragrance-retaining layer applied was changed compared to Example 11-1. In the table, NCO / OH represents the ratio of the number of moles of isocyanate groups in the curing agent to the number of moles of hydroxyl groups in the polyester resin. A coating agent composition was applied to the entire surface of one side of the base layer, which is OPP, using a wire bar, and dried to obtain a fragrance-retaining layer. After drying the adhesive with a wire bar, apply at a rate of 3.0g / m². 2 The material was applied in this manner and dried to obtain an adhesive layer. Each laminate was obtained by dry laminating a sealant layer, which is CPP, onto the adhesive layer and aging it at 40°C for 3 days. Similarly, the same results as the corresponding examples and comparative examples were obtained when the substrate layer was changed to MDOPE and the sealant layer to LLDPE.

[0054] (Examples 10-2 to 10-4) Examples 10-2 and 10-3 are examples in which a printing layer consisting of blue ink or white ink is provided between the fragrance-retaining layer and the adhesive layer compared to Example 10-1. Example 10-4 is an example in which a printing layer made of blue ink is provided between the base layer and the fragrance-retaining layer compared to Example 10-1. These examples are examples obtained by adding a printing step under the following printing conditions to the method for obtaining the laminate of Example 1 described above. In the printing process, the ink used was a mixture of blue ink and white ink diluted with a solvent of ethyl acetate / propyl acetate / isopropyl alcohol in a mass ratio of 50 / 30 / 20, and the viscosity was adjusted to 15 seconds using a Rigo cup No. 3. The ink was then applied as a solid color to the fragrance-retaining layer or substrate layer and dried to obtain the printed layer.

[0055] (Printing conditions for reverse-printing ink compositions) Coating machine: Gravure printing machine Coating speed: 100 m / min Printing plate: Helio 175 line / inch 15 (130°) solid plate Drying temperature: 55℃

[0056] (Application conditions for each fragrance-retaining layer composition) Coating machine: Gravure printing machine Coating speed: 100 m / min Printing plate: Helio 250 line / inch (130°) solid plate Drying temperature: 80℃ The amount of fragrance-retaining layer applied in the examples and comparative examples listed in Table 1 was 1.0 g / m². 2 That is the case.

[0057] (base material layer) OPP (Biaxially oriented polypropylene film (P2161, 25 μm thickness, Toyobo Co., Ltd.)) MDOPE (Uniaxially oriented polyethylene film (PE3K-H, 25 μm thickness, Futamura Chemical Co., Ltd.))

[0058] (Printing ink composition) Blue ink: Bellflora R Blue 800 (Sakata Inx Co., Ltd.) White ink: Bellflora R White 115 (Sakata Inx Co., Ltd.)

[0059] (glue) Adhesive: Takelac A-969V / Takenate A-5 (Mitsui Chemicals, Inc.) Solid content 30% by mass

[0060] (Main component for fragrance retention layer (polyester resin)) (The unsaturated polycarboxylic acid content is the unsaturated polycarboxylic acid content in the total polycarboxylic acids constituting the polyester resin.) Fumaric acid-containing polyester 1: Glass transition temperature 70°C, unsaturated polycarboxylic acid content 30%, hydroxyl value 25 mg KOH / g, molecular weight 2,000-3,000, solids content 100% Fumaric acid-containing polyester 2: Glass transition temperature 60°C, unsaturated polycarboxylic acid content 60%, hydroxyl value 32 mg KOH / g, molecular weight 6,000, solids content 100% Fumaric acid-containing polyester 3: Glass transition temperature 50°C, unsaturated polycarboxylic acid content 90%, hydroxyl value 35 mg KOH / g, molecular weight 4,000, solids content 100% Fumaric acid-containing polyester 4: Glass transition temperature 80°C, unsaturated polycarboxylic acid content 10%, hydroxyl value 25 mg KOH / g, molecular weight 5,000, solids content 100% Fumaric acid-containing polyester 5: Glass transition temperature 30°C, unsaturated polycarboxylic acid content 60%, hydroxyl value 30 mg KOH / g, molecular weight 6,000, solids content 100% Maleic acid-containing polyester 1: Glass transition temperature 65°C, unsaturated polycarboxylic acid content 40%, hydroxyl value 25 mg KOH / g, molecular weight 3,500, solids content 100% Unsaturated polycarboxylic acid-free polyester 1: Glass transition temperature 60°C, unsaturated polycarboxylic acid content 0%, hydroxyl value 25 mg KOH / g, molecular weight 5,000, solids content 100%

[0061] (Hardening agent for fragrance retention layer) Takenate D-110N: XDI-TMP Adduct (Mitsui Chemicals, Inc.) NCO content = 11.5% by mass, solid content 75% by mass Duranate 24A-90E: HDI-Biuret (Asahi Kasei Corporation) NCO content = 21.2% by mass, solid content 90% by mass Desmodur ultra Z4470BA: IPDI-isocyanurate (Sumika Covestro Co., Ltd.) NCO content = 11.9% by mass, solids content 70% by mass (Solvent for forming a fragrance-retaining layer) MEK: Methyl ethyl ketone

[0062] (Sealant layer used) CPP (Unoriented Polypropylene Film (P1128, 25μm thickness, Toyobo Co., Ltd.)) LLDPE (Linear low-density polyethylene unoriented film (Unilux LS-711C, 50 μm thickness, Idemitsu Unilux Co., Ltd.))

[0063] <Fragrance retention test method> The above laminate was cut into 7cm squares, and one side was folded in half, with the long and short sides heat-sealed. One of the following contents was placed in each of the four resulting bag-like objects: curry powder (1g), coffee powder (1g), fabric softener (4g), and liquid shampoo (4g). The remaining side was heat-sealed to create airtight bags. The prepared bags were placed in glass bottles and sealed, and the leakage of fragrance after storage at 23°C for 7 days was evaluated as follows. Five testers skilled in fragrance evaluation checked the fragrance atmosphere inside the glass bottles and judged according to the following criteria. The table below shows the amount of fragrance leakage that was evaluated as being most highly by the testers. Curry powder: Red can curry powder (S&B Foods Co., Ltd.) Coffee powder: Blendy Instant Coffee (Ajinomoto AGF Co., Ltd.) Liquid Shampoo: Pantene Effortless Complete Night Repair Shampoo (P&G) Fabric softener: Soflan Aroma Rich Sweet Floral Aroma scent (LION Corporation) Evaluation Criteria ◎: No fragrance leakage ○: Slight fragrance leakage present. △: Scent leakage present ×: Strong scent leaking out.

[0064] <Method for evaluating adhesion> After obtaining each printed OPP film, the adhesion was evaluated based on the degree to which the printed film peeled off the film when cellophane tape (registered trademark) was applied to the printed surface and rapidly peeled off. Evaluation Criteria A: Printed film that does not peel off the film at all. B: Less than 20% of the printed coating area is peeled off the film. C: Printed coatings where 20% to less than 50% of the surface area is peeled off from the film. D: Printed coating that peels off from the film by 50% or more in terms of surface area ratio.

[0065] <Method for measuring laminate strength> Each laminate was cut into 15 mm wide strips, and the T-type peel strength (N / 15 mm) was measured using a peel tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) as the peel strength. Evaluation Criteria ○:1.2N / 15mm or more △: Less than 1.2N / 15mm, less than 0.7N / 15mm ×: 0.7N / less than 15mm

[0066] [Table 1]

[0067] [Table 2]

[0068] [Table 3]

[0069] According to each example, it was possible to obtain laminates that possessed sufficient fragrance retention and excellent adhesion and lamination strength. In contrast, Comparative Example 1, which did not use a curing agent to form the fragrance-retaining layer, exhibited insufficient laminate strength. Comparative Example 2, which used an unsaturated polyester with a low glass transition temperature to form the fragrance-retaining layer, showed poor fragrance retention. Furthermore, Comparative Example 3, which did not use an unsaturated polyester, exhibited poor adhesion. Furthermore, in Examples 10-1 to 10-4, which used the fragrance-retaining coating composition of Example 1, kept the amount applied after drying the same, and varied the presence or position of the printed layer, all examples exhibited sufficient fragrance retention and laminate strength. Furthermore, in Examples 11-1 to 11-4, which used the fragrance-retaining coating agent composition of Example 1 but varied the amount applied and did not include a printed layer, all examples exhibited sufficient fragrance retention and lamination strength.

Claims

1. A laminate comprising, in this order, a base layer, a layer formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a polyisocyanate curing agent, an adhesive layer, and a sealant layer.

2. The laminate according to claim 1, having a printed layer between the layer obtained by curing the unsaturated polyester resin having a glass transition temperature of 35°C or higher with a polyisocyanate curing agent and the adhesive layer.

3. The laminate according to claim 1 or 2, wherein the unsaturated polyester resin with a glass transition temperature of 35°C or higher is an unsaturated polyester resin containing structural units derived from fumaric acid and / or maleic acid.

4. The dry coating amount of the layer formed by curing the unsaturated polyester resin having a glass transition temperature of 35°C or higher with a polyisocyanate curing agent is 0.05 to 5.0 g / m². ２ The laminate according to claim 1 or 2.

5. A laminate for packaging films having a layer on top of a sealant layer, the layer being formed by curing an unsaturated polyester resin with a glass transition temperature of 35°C or higher with a polyisocyanate curing agent.

6. It contains an unsaturated polyester resin with a glass transition temperature of 35°C or higher and a polyisocyanate curing agent. The aforementioned polyisocyanate curing agent is a coating composition comprising an aromatic aliphatic diisocyanate.

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