JP2020055210A - Laminate and retort packaging bag using the same - Google Patents

Abstract

To provide a laminate whose content can be seen through, the laminate applicable to a metal detector, having gas barrier properties, with excellent laminate strength even having gone through a retort treatment, etc. without a defective appearance, and also to provide a retort packaging bag using the same.SOLUTION: A laminate is obtained by laminating a surface substrate, a gas barrier layer, an adhesion layer, a substrate, an adhesion layer, and a thermofusion layer. The gas barrier layer includes an inorganic vapor-deposition layer and a coat layer. The adhesion layer is a solventless-type adhesion layer. The coat layer contains one of a silicon compound expressed by a general formula (1) below and a hydrolyzate thereof, one of a silicon compound expressed by a general formula (2) below and a hydrolyzate thereof, and a water-soluble polymer having a hydroxyl group: Si(OR)...(1), and (RSi(OR))...(2) (in which Rand Rare CH, CHor CHOCH, and Ris an organic functional group).SELECTED DRAWING: Figure 1

Description

  The present invention has a particularly high gas barrier property in a laminate made of a plastic film used in the field of packaging of foods and the like, thereby shielding the contents from oxygen and water vapor in the atmosphere and suppressing deterioration and deterioration of the contents. The present invention relates to a laminated body having a gas barrier property and a packaging bag for retort using the same.

  In recent years, packaging materials used for the packaging of foods, pharmaceuticals, etc., use oxygen, water vapor, and other gases (gases) that alter the contents so as to suppress the alteration of the contents and maintain their functions and properties. It is required to be able to cut off but have barrier properties.

  Therefore, conventionally, a metal foil made of a metal such as aluminum which is less affected by temperature, humidity and the like has been generally used as a gas barrier layer.

  However, packaging materials using metal foils made of metal such as aluminum have excellent gas barrier properties, but the contents cannot be checked through them. When disposed after use, they are treated as incombustibles. There is a problem that it has to be performed, a metal detector cannot be used when inspecting the packaged contents, and so on.

  Therefore, in order to overcome these disadvantages, for example, inorganic oxides such as silicon oxide, aluminum oxide, and magnesium oxide are formed by a thin film forming means such as a vacuum evaporation method or a sputtering method described in Patent Document 1 or Patent Document 2. A vapor deposition film formed by forming a vapor deposition thin film made of an oxide on a polymer film has been developed.

  However, a polymer film provided with a vapor-deposited thin film made of an inorganic oxide tends to deteriorate the adhesion between layers due to deterioration of the material of the vapor-deposited thin film and the like due to heat treatment. When the treatment is performed, delamination of the vapor-deposited thin film layer may occur, and the gas barrier property may decrease. Further, the vapor-deposited thin film layer is brittle because it is made of an inorganic oxide, and the vapor-deposited thin film layer is easily damaged by external force such as stretching or bending, and the gas barrier property is likely to be reduced.

In addition, for example, in Patent Document 3, a sol-gel method including an alkoxysilane such as Si (O—CH ₃ ) ₄ , a silane coupling agent such as an epoxysilane, and polyvinyl alcohol on a resin substrate is used. Laminated films obtained by condensation have been proposed.

  However, since this coating layer is formed by hydrogen bonding, it has a problem that it is easily swelled and dissolved by water, and there is a problem that the gas barrier property is easily deteriorated under severe conditions such as boiling and retorting.

  For this reason, for example, in Patent Document 4, a vapor-deposited layer made of an inorganic compound is used as a first layer, and (1) a water-soluble polymer and (2) I) one or more metal alkoxides or metal alkoxide hydrolysates Or II) a gas barrier packaging material in which a coating agent mainly containing an aqueous solution containing tin chloride or a mixed solution of water and alcohol is applied, heated and dried, and a gas barrier coating layer is sequentially laminated as a second layer. ing.

This gas barrier packaging material exhibits high gas barrier properties, and has water resistance and moisture resistance, and has a certain degree of heat resistance. However, the second layer of the gas barrier packaging material has a metal alkoxide hydrolyzate and an aqueous solution having a hydroxyl group. When it is used as a packaging material requiring boil and retort treatment, it has a problem that the coating layer swells and the gas barrier property is deteriorated because of hydrogen bonding with the hydrophilic polymer.

  On the other hand, as for a packaging material having a gas barrier layer, a dry lamination method using a solvent-based adhesive has been generally used when a plurality of layers are laminated to form a laminate.

  Since solvent-based adhesives contain volatile organic compounds as solvents, if this solvent remains, contamination of the contents due to an unpleasant odor, generation of air bubbles due to volatilization during lamination, and foreign matter on the bonding surface etc. There are adverse effects such as residual appearance which impairs the appearance, and further lowers the laminate strength and causes peeling, and has to be completely removed.

  For this purpose, it is necessary to heat the resin layer including the solvent-based adhesive and to volatilize and remove the solvent.However, during this heating, the resin layer may be thermally deformed. The appearance was adversely affected.

  Further, it is desired that the use of a solvent is not used from the viewpoint of environmental problems, and a packaging material laminated by solventless adhesion is required.

  In contrast to the dry lamination method, the non-solvent lamination method using a solventless adhesive does not require a drying oven and does not use a solvent, so there is no need to worry about residual solvents or thermal deformation of the resin layer. There is.

  However, the solventless adhesive does not use a solvent for adjusting the viscosity of the coating liquid, so that in order to improve the coating properties, the average molecular weight of the base resin and the curing agent is reduced to reduce the coating liquid. We are trying to increase the viscosity.

  For this reason, the initial cohesive force immediately after coating is small, and curing for several days is required in order to obtain adhesive strength by lamination.

  In this curing, fine bubbles and voids contained in the adhesive layer move and concentrate and grow, so that a spot (yuzu skin, satin) appearance defect may occur at the interface with the gas barrier layer in the laminate. . In particular, in a laminate having a high gas barrier property, bubbles are difficult to escape, and the problem is remarkable.

U.S. Pat. No. 3,442,686 JP-B-63-28017 JP-A-4-345841 Japanese Patent Application Laid-Open No. Hei 7-16491

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an inorganic vapor-deposited layer and a coat layer that solve problems such as residual solvent and thermal deformation of a resin layer during lamination. By providing a laminate having a gas barrier layer and a packaging bag for retort using the same, it is excellent in transparency, the contents can be seen through, and can be applied to a metal detector, has gas barrier properties, and has a gas barrier property. Another object of the present invention is to provide a laminate having excellent lamination strength even without heat treatment such as retort treatment and having no appearance defect, and a packaging bag for retort using the laminate.

The present invention has been made to solve these problems.
That is, the invention according to claim 1 is a laminate formed by laminating a surface substrate, a gas barrier layer, an adhesive layer, a substrate, an adhesive layer, and a heat sealing layer, wherein the gas barrier layer is an inorganic vapor-deposited layer. And a coating layer, wherein the adhesive layer is a solventless adhesive layer, and the coating layer comprises one of a silicon compound represented by the following general formula (1) and a hydrolyzate thereof, and the following general formula ( A laminate comprising: one of the silicon compound represented by 2) and a hydrolyzate thereof; and a water-soluble polymer having a hydroxyl group.

Si (OR ¹ ) ₄ ... (1)
(R ² Si (OR ³ ) ₃ ) _n (2)
(However, R ¹ and R ³ are CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OCH ₃ , and R ² is an organic functional group)
According to a second aspect of the present invention, the solventless adhesive layer includes a polyisocyanate component and a polyol component, the polyisocyanate component includes an araliphatic diisocyanate component, and the polyol component is partially acid-terminated. The laminate according to claim 1, wherein the laminate is formed.

  The invention according to claim 3 is the laminate according to claim 1 or 2, wherein the inorganic vapor-deposited layer contains at least one of aluminum oxide and silicon oxide.

  According to a fourth aspect of the present invention, there is provided a packaging bag for a retort, comprising the laminate according to any one of the first to third aspects.

  The gas barrier laminate according to the present invention has high hot water resistance, high pinhole resistance to physical impact, and can maintain excellent gas barrier properties even when subjected to retort treatment, boil treatment, heating cooking, and the like. By solving the processing problem of the laminating process for producing a body, a gas barrier laminate having no concern about residual solvent has been made possible.

FIG. 2 is a schematic cross-sectional view illustrating a configuration example of a laminate according to the present invention. It is the top view which showed an example of the packaging bag for retorts which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described in detail. In the following description, reference is made to the drawings as appropriate, but the embodiments described in the drawings are exemplifications of the present invention, and the present invention is not limited to the embodiments described in these drawings.

  FIG. 1 is a cross-sectional view illustrating a configuration example of the laminate of the present invention.

  As shown in FIG. 1, a laminate (10) according to an embodiment of the present invention includes a surface substrate (11), a gas barrier layer (12) including an inorganic vapor deposition layer (13) and a coat layer (14). , An adhesive layer (15), a base material (16), an adhesive layer (15 ′), and a heat sealing layer (17).

(Surface substrate)
The surface substrate (11) used in the present invention is made of a resin material processed into a film, and is preferably transparent. Specific examples of such a resin material include polyester films such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN); polyolefin films such as polyethylene and polypropylene; polystyrene films; polyamide films such as 66-nylon; Examples include engineering plastic films such as a polycarbonate film, a polyacrylonitrile film, and a polyimide film.

  As the resin material, those having mechanical strength and dimensional stability are preferably used, and may be stretched or unstretched. However, stretched ones are preferably used. Stretching is more preferred.

  Among the resin materials as described above, when used as a packaging material, in consideration of price, moisture resistance, filling suitability, texture, and disposability, polyamide films and polyester films are preferable, and polyester films are more preferable. .

  The thickness of the surface substrate (11) is not particularly limited, but is preferably 3 to 200 μm, more preferably about 6 to 30 μm in consideration of suitability as a packaging material and workability. It is.

  Various conventionally known additives and stabilizers, for example, an antistatic agent, a plasticizer, an antioxidant, and the like can be applied to the surface substrate (11) as necessary.

  The surface of the surface substrate (11) may be subjected to various treatments such as a corona treatment, a plasma treatment, and an ozone treatment as a pretreatment in order to improve the adhesion to the gas barrier layer (12). Furthermore, chemical treatment, solvent treatment, application of an anchor coat agent, and the like may be performed.

  When applying the anchor coating agent, various one-component or two-component curing materials can be used. For example, acrylic resin, epoxy resin, polyester resin, acrylic urethane resin, polyester urethane resin , Various materials such as those based on organic silane compounds such as polyether urethane resin, polyimide resin, melamine resin, phenol resin, inorganic silica such as organically modified colloidal silica, silane coupling agent and hydrolyzate thereof And various materials can be used alone or as a mixture or a composite. When a curing agent is used, any curing agent can be used depending on the material that is the main agent.

  The thickness of such an anchor coating agent is not particularly limited, but may be, for example, in the range of 0.01 to 5 μm, more preferably in the range of 0.03 to 3 μm, and more preferably in the range of 0.05 to 2 μm. It is particularly preferred that it is within the range.

(Gas barrier layer)
The gas barrier layer (12) includes an inorganic vapor deposition layer (13) and a coat layer (14).

  Examples of the inorganic compound used for the inorganic vapor deposition layer (13) include oxides such as silicon, aluminum, titanium, zirconium, tin, and magnesium, nitrides thereof, fluorides thereof, and mixtures thereof. However, silicon oxide or aluminum oxide is preferably used.

  The inorganic vapor deposition layer (13) can be formed by a vacuum process such as a vacuum vapor deposition method, a sputtering method, an ion plating method, or a plasma vapor deposition method. When a vacuum evaporation method is used, as a heating means of the evaporation material, for example, a method such as electron beam heating, resistance heating, or induction heating can be used. When the electron beam heating method is used, it can be said that the degree of freedom in selecting the evaporation material is large.

  When the thickness of the inorganic vapor-deposited layer (13) is small, it is difficult to form the inorganic vapor-deposited layer (13) as a uniform continuous film, and sufficient gas barrier properties cannot be obtained. And the cracks may occur when the laminate (10) is bent or pulled. Based on these, the thickness of the inorganic vapor deposition layer (13) is, for example, in the range of 5 nm to 500 nm.

  The coat layer (14) is formed of one or more of a silicon compound represented by the following general formula (1) and a hydrolyzate thereof, and a silicon compound represented by the following general formula (2) and a hydrolyzate thereof. Among them, it is obtained by applying and drying one or more coating solutions containing a water-soluble polymer having a hydroxyl group.

Si (OR ¹ ) ₄ ... (1)
(R ² Si (OR ³ ) ₃ ) _n (2)
(However, R ¹ and R ³ are CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OCH ₃ , and R ² is an organic functional group)
In general, a film formed using a coating solution containing a polymer material and a metal alkoxide and / or a hydrolyzate thereof has higher flexibility and cracks and the like as compared with a film composed of only a metal oxide. It is difficult.

  However, in such a film, the metal oxide is not microscopically dispersed uniformly, and a high gas barrier property may not be obtained in some cases.

  However, by using a water-soluble polymer as the polymer material, a strong hydrogen bond is created between the hydroxyl group in the polymer and the hydroxyl group of the hydrolyzate of the metal alkoxide. Upon condensation, the metal oxide can be uniformly dispersed in the water-soluble polymer.

  Therefore, it is possible to achieve a gas barrier property close to a film made of only a metal oxide. Therefore, by forming such a coating layer (14) on the inorganic vapor-deposited layer (13), flexibility can be imparted, and a gas barrier property that is much higher than when these layers are used alone is obtained. It is possible to demonstrate.

However, the coating layer (14) is simply formed by using a coating solution containing only a metal alkoxide having no organic functional group such as Si (OR) ₄ or Al (OR) ₃ and / or a hydrolyzate thereof and a water-soluble polymer. ) Is formed only by hydrogen bonding, and when used in a harsh environment, it may swell due to intrusion of water and eventually cause dissolution.

  Therefore, when the coat layer (14) is formed with such a material configuration, the adhesion and gas barrier properties may easily deteriorate under severe conditions such as a high-temperature and high-humidity environment.

On the other hand, one or more of the above-described general formula (1) and its hydrolyzate, and one or more of the silicon compound and its hydrolyzate represented by the general formula (2) and a hydroxyl group By forming a coat layer (14) using a coating solution containing a water-soluble polymer having the following formula, the organic functional group (R ² ) represented by the general formula (2) crosslinks to form a network, Properties can be significantly improved.

Particularly when the organic functional group (R ² ) is a water-insoluble functional group such as a vinyl group, an epoxy group, a methacryloxy group, a ureide group, and an isocyanate group, higher water resistance can be achieved.

When the organic functional group (R ² ) is a vinyl group, a methacryloxy group, or the like, irradiation of ionizing radiation such as an ultraviolet ray or an electron beam can be performed in the production process.

When the silicon compound represented by the general formula (2) is a multimer, a trimer is preferable, and more preferably, a general formula (NCO-R ⁴ Si (OR ³ ) ₃ ) ₃ (wherein R ⁴ Is 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate represented by (CH ₂ ) _n , where n is 1 or more, and is a condensate of 3-isocyanatoalkylalkoxysilane.

  This 1,3,5-tris (3-trialkoxysilylalkyl) isocyanurate is generally added to an adhesive or the like as in the case of 3-isocyanatoalkylalkoxysilane, and is known to be used as an adhesion improver. Have been.

In the case of 3-isocyanatoalkylalkoxysilane, the reactivity of the isocyanate group, which is an organic functional group (R ² ), is high, and the stability of the coating liquid is low. The property is that the viscosity of the coating liquid is easily kept stable while ensuring the dispersibility of the coating liquid.

When two types of silicon compounds represented by the above general formulas (1) and (2) are used, the ratio of these silicon compounds is, for example, the weight of Si (OR ¹ ) ₄ in terms of SiO _2. and ^R 2 Si ratio of _{^{(OR 3) R 2 Si (}} OR 3) to the sum of the ^R 2 Si _{(OH) 3-equivalent} weight of _{3 3} of ^R 2 Si _{(OH) 3} in terms weight, from 1% to 50% May be set within the range.

This is because if it is less than 1%, the water resistance of the coat layer (14) decreases, and if it exceeds 50%, the organic functional group (R ² ) serves as a gas barrier hole, and the gas barrier property decreases.

  In order to further improve the water resistance and high gas barrier properties required for boil and retort treatments, the above ratio may be set to be 5% to 30%.

  In this way, the liquid contents or the water-containing contents are subjected to boiling sterilization treatment or pressurization / heat sterilization treatment, and also achieve sufficient water resistance and high gas barrier properties for long-term storage in a high-temperature and high-humidity environment. be able to.

  As the water-soluble polymer having a hydroxyl group used in the coat layer (14), for example, polyvinyl alcohol, starch, celluloses and the like can be preferably used. In particular, when polyvinyl alcohol is used, the gas barrier property is most excellent.

  This is presumably because polyvinyl alcohol is a polymer containing the most hydroxyl group in the monomer alone.

  Polyvinyl alcohol is generally obtained by saponifying polyvinyl acetate, and is obtained from a so-called partially saponified polyvinyl alcohol in which acetic acid groups remain tens of percent, to a completely saponified polyvinyl alcohol in which only a few percent acetic acid groups remain. Up to and including.

  In addition, there are various types of molecular weights of polyvinyl alcohol having a degree of polymerization of about 300 to several thousands, but there is no problem in the effect of using any of the molecular weights. However, high-molecular-weight polyvinyl alcohol having a high degree of saponification and a high degree of polymerization generally has high water resistance and can be said to be preferable.

In order to promote the hydrolysis reaction of Si (OR ¹ ) ₄ or the like, an acid or alkali catalyst is added to the coating liquid for the coating layer (14) as described above, in addition to alcohol, water, etc., preferably. Hydrolysis with an acid is preferred because it is easy to control. At this time, a generally known catalyst such as tin chloride or acetylacetonate may be added to further control the hydrolysis.

  Such a method of mixing the coating liquid for the coating layer (14) may be mixed in any order. For example, the silicon compound represented by the general formula (1) and the silicon compound represented by the general formula (2) are separately hydrolyzed, and then added to a solution containing a water-soluble polymer. Is also good. This method is excellent in terms of the dispersibility of the silicon compound and the efficiency of hydrolysis.

  The coating liquid for the coating layer (14) is used to improve the wettability and adhesion between the coating layer (14) and the adhesive layer or various inks, and to prevent the occurrence of cracks due to shrinkage of the coating layer (14). Considering this, various additives may be added.

  As the additives, for example, isocyanate compounds, clay minerals such as colloidal silica and smectite, stabilizers, coloring agents, rheology modifiers, and mixtures thereof can be used.

  Examples of the method for forming the coat layer (14) include dipping, roll coating, gravure coating, reverse gravure coating, air knife coating, comma coating, die coating, screen printing, spray coating, and gravure. The coating liquid can be applied by an offset method or the like.

  As the drying method at this time, it is possible to dry by a hot air drying method, a hot roll drying method, a high frequency irradiation method, an infrared irradiation method, an ionizing radiation irradiation method such as an ultraviolet ray or an electron beam, or a combination thereof.

  When the thickness of such a coating layer (14) is small, it is difficult to form the coating layer (14) as a uniform continuous film, and sufficient gas barrier properties cannot be obtained. When the thickness is large, cracks and the like are easily generated in the film. The thickness of the coat layer (14) can be, for example, in the range of 0.01 μm to 50 μm.

(Adhesive layer <solvent-free adhesive>)
The adhesive layers (15, 15 ') are adhesive layers using a solventless adhesive. The solventless adhesive is an adhesive composition containing a polyisocyanate component and a polyol component, and may be a so-called two-component curing type in which the polyisocyanate component and the polyol component are mixed at the time of use, or a polyisocyanate component. And a so-called one-pack type in which the polyol component and the polyol component are mixed in advance.

  In addition, the adhesive layer (15) and the adhesive layer (15 ') may be different from each other in adhesive composition, but there is no problem even if the same material is used in consideration of workability and the like.

  The adhesive composition of the present invention is preferably of a two-part curing type. Further, in the adhesive composition of the present invention, a plurality of types of the polyisocyanate component and the polyol component may be used respectively. The polyol component may be a mixture of a polyol and a monofunctional alcohol, or may be a polyol alone.

<Polyisocyanate component>
Examples of the polyisocyanate include a polyisocyanate monomer, a polyisocyanate derivative, and a polyisocyanate-terminated prepolymer.

Examples of the polyisocyanate monomer include an aliphatic diisocyanate, an alicyclic diisocyanate, an araliphatic diisocyanate, and an aromatic diisocyanate.

  Examples of the aliphatic diisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (also called HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 2,3-butylene diisocyanate, 1,3-butylene diisocyanate, Examples thereof include dodecamethylene diisocyanate and 2,4,4-trimethylhexamethylene diisocyanate, but are not limited thereto.

  Examples of the alicyclic diisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate, isophorone diisocyanate (also known as IPDI), 1,3-cyclopentane diisocyanate, 1,3-cyclohexane diisocyanate, and 1,4. -Cyclohexane diisocyanate, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 4,4'-methylenebis (cyclohexylisocyanate), 1,4-bis (isocyanatomethyl) cyclohexane and the like. However, the present invention is not limited to these.

  As the araliphatic diisocyanate, for example, 1,3- or 1,4-xylylene diisocyanate or a mixture thereof (alias: XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate or a mixture thereof (alias: TMXDI), ω, ω'-diisocyanato-1,4-diethylbenzene, 1,3- or 1,4-bis (1-isocyanato-1-methylethyl) benzene or a mixture thereof, and the like. Not limited.

  Examples of the aromatic diisocyanate include m- or p-phenylene diisocyanate or a mixture thereof, methylenebis (4,1-phenylene) diisocyanate (also called MDI), 2,4- or 2,6-tolylene diisocyanate or a mixture thereof ( Other names include, but are not limited to, 4,4-toluidine diisocyanate (also known as TODI), 4,4′-diphenylether diisocyanate, 1,5-naphthalenediisocyanate (also known as NDI).

  Examples of the polyisocyanate derivative include multimers of polyisocyanate monomer (for example, dimer, trimer, and pentamer), burette, adduct, allophanate, and the like. It is not limited to.

  The diisocyanate-terminated prepolymer is a urethane prepolymer having two isocyanate groups at the molecular terminals, and includes a diisocyanate (a diisocyanate selected from a polyisocyanate monomer, a polyisocyanate derivative, and a diisocyanate-terminated prepolymer) and a polyol (described later). In particular, diol) can be obtained by a urethanization reaction at a ratio at which the equivalent ratio of diisocyanate to hydroxyl group of the diol (NCO / OH) is larger than 1.

  The polyisocyanate component is used as one or a mixture of two or more of a polyisocyanate monomer, a polyisocyanate derivative, and a diisocyanate-terminated prepolymer. The polyisocyanate component includes a diisocyanate containing an araliphatic diisocyanate, It is desirable to include a diisocyanate-terminated prepolymer obtained by reacting with a diol containing a macrodiol.

By including such a diisocyanate-terminated prepolymer, an increase in the viscosity of the adhesive composition can be suppressed, and the workability when manufacturing a laminate can be improved.

  Further, as the araliphatic diisocyanate used for the diisocyanate-terminated prepolymer desirably contained in the polyisocyanate component, XDI can be suitably used.

<Polyol component>
As the polyol component, for example, the average number of functional groups exceeds 2. That is, the polyol component contains a diol containing a macrodiol and a crosslinkable polyol having three or more hydroxyl groups, and / or a urethane-modified polyol in which the diol and the crosslinkable polyol are urethane-modified. It contains.

  For this reason, the average number of functional groups of the polyol component is more than 2, preferably 2.05 or more, more preferably 2.1 or more, and usually 5.0 or less.

  The diol is a polyol having two hydroxyl groups, and includes, for example, a low molecular weight diol and a macrodiol.

  The low molecular weight diol is a bifunctional polyol having two hydroxyl groups and having a number average molecular weight of, for example, less than 400, preferably less than 300, such as aliphatic diol, alicyclic diol, and aromatic diol. No.

  Examples of the aliphatic diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, 1,2-, 1,3- or 1,4-butanediol, and 2-methyl- Examples include, but are not limited to, 1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 12-hydroxystearyl alcohol, hydrogenated dimer diol, and the like.

  Examples of the alicyclic diol include, but are not limited to, hydrogenated bisphenol A, hydrogenated xylylene diol, and cyclohexanediol.

  Examples of the aromatic diol include, but are not limited to, bisphenol A, bishydroxyethyl terephthalate, catechol, resorcin, hydroquinone, 1,3- or 1,4-xylylene diol.

  Macrodiol has two hydroxyl groups, the number average molecular weight is, for example, 400 or more, preferably 500 or more, for example, polyester diol, polycaprolactone diol, polycarbonate diol, polyether diol and the like, It is not limited to.

  The polyester diol can be obtained by a condensation reaction between a dibasic acid and a low molecular weight diol as described above, or a transesterification reaction between an alkyl ester of a dibasic acid and a low molecular weight diol as described above.

  Examples of the dibasic acid include succinic acid, glutaric acid, adipic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, dodecane diacid, dimer acid, hexahydrophthalic acid, phthalic acid, isophthalic acid, and terephthalic acid. Such aliphatic, alicyclic, and aromatic dicarboxylic acids can be exemplified.

  Examples of polycaprolactone diol include, for example, polycaprolactone diol obtained by ring-opening polymerization of ε-caprolactone.

  Examples of the polycarbonate diol include, for example, a polycarbonate diol obtained by a condensation reaction of dimethyl carbonate, diethyl carbonate and the like with the low molecular weight diol as described above.

  The polyether diol can be obtained, for example, by subjecting an alkylene oxide such as ethylene oxide or propylene oxide to an addition reaction using the above-described low molecular weight diol as an initiator.

  Alternatively, for example, polytetramethylene ether glycol obtained by ring-opening polymerization of tetrahydrofuran or the like can be mentioned as an example of the polyether diol.

  The macrodiol as described above may be used alone or as a mixture of two or more without any problem.

  As the diol, one or two or more diols are selected from low molecular weight diols and macrodiols, and it is desirable to include macrodiols.

  The crosslinkable polyl includes a crosslinkable polyol having three or more hydroxyl groups and all of the hydroxyl groups being secondary or tertiary hydroxyl groups. More specifically, for example, trifunctional or higher functional polypropylene polyol, cyclohexane Triol, inositol and the like can be exemplified, and preferably a tri- or higher functional polypropylene polyol.

  A trifunctional or higher functional polypropylene polyol is a polypropylene polyol having three or more hydroxyl groups, and all of the hydroxyl groups are secondary or tertiary hydroxyl groups.

  As a method for obtaining such a polypropylene polyol, for example, a method in which a polyhydric alcohol having three or more hydroxyl groups is used as an initiator and an addition reaction of propylene oxide is given.

  Examples of the polyhydric alcohol having three or more hydroxyl groups include, for example, glycerin, 2-methyl-2-hydroxymethyl-1,3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,2 Examples include, but are not limited to, 6-hexanetriol, trimethylolpropane, pentaerythritol, diglycerin, xylitol, sorbitol, mannitol, allitol, iditol, dulcitol, altitol, inositol, and sucrose.

  As such a trifunctional or higher functional polypropylene polyol, a polypropylene polyol obtained by subjecting a polypropylene oxide to an addition reaction using a trihydric alcohol as an initiator can be preferably used.

  By using a trifunctional polypropylene polyol, it is possible to suppress an increase in the viscosity of the coating liquid due to a crosslinking reaction, thereby contributing to an improvement in workability.

  The crosslinkable polyol is not limited to the above as long as it has three or more secondary or tertiary hydroxyl groups. For example, while having three or more secondary or tertiary hydroxyl groups, A crosslinkable polymer having one or more primary hydroxyl groups may be used.

  The urethane-modified polyol can be obtained by subjecting the above-mentioned diol and crosslinkable polyol to a urethane-forming reaction with the above-mentioned polyisocyanate monomer and / or polyisocyanate derivative.

  At this time, the urethanization reaction is performed at a ratio at which the equivalent ratio (NCO / OH) of the isocyanate group of the polyisocyanate monomer and / or the polyisocyanate derivative to the hydroxyl group of the diol and the crosslinkable polyol becomes smaller than 1.

  In the urethane-modified polyol, the polyisocyanate monomer and / or the polyisocyanate derivative preferably include an araliphatic diisocyanate.

  Further, the hydroxyl equivalent of the urethane-modified polyol is, for example, 150 to 1000, preferably 200 to 750, and the number average molecular weight can be, for example, 300 to 2,000.

  The polyol component contains the above-mentioned diol and crosslinkable polyol and / or contains the above-mentioned urethane-modified poly.

  Then, after blending each of the above-mentioned components, that is, the diol and the crosslinkable polyol, and / or the urethane-modified polyol, the terminal hydroxyl group of each of the components contained in the polyol component is partially acid-terminated. Thus, it can be prepared.

  By modifying the polyol component with a terminal acid as described above, it is possible to improve the adhesive strength, and as a result, it is possible to prevent a decrease in the content resistance due to boiling or retorting.

  Examples of the method of terminal-modifying the polyol component with a terminal acid include a method of reacting an acid anhydride with a terminal hydroxyl group of each component contained in the polyol component.

  Examples of the anhydride include, but are not limited to, trimellitic anhydride, phthalic anhydride, maleic anhydride, and pyromellitic anhydride.

  The urethane-modified polyol is prepared by, for example, blending the diol and the crosslinkable polyol described above, and blending the above-mentioned polyisocyanate monomer and / or polyisocyanate derivative, and subjecting them to a urethane-forming reaction. Can be blended.

  In this case, the mixing ratio of the diol and the crosslinkable polyol and the urethane-modified polyol in the polyol component is appropriately determined according to the mixing ratio of the polyisocyanate monomer and / or the polyisocyanate derivative to the diol and the crosslinkable polyol. It will be.

  Here, the acid value (mgKOH / g) can be determined based on JIS K0070.

  In the solventless adhesive as described above, if necessary, for example, an oxygen acid of phosphorus or a derivative thereof or a silane coupling agent is added to one or both of the polyisocyanate component and the polyol component. And, if necessary, a monofunctional alcohol may be added to the polyol component.

  Examples of the oxygen acid of phosphorus include phosphoric acids such as hypophosphorous acid, phosphorous acid, orthophosphoric acid, hypophosphoric acid, and condensed phosphoric acids such as metaphosphoric acid, pyrophosphoric acid, tripolyphosphoric acid, and polyphosphoric acid. Can be.

  Examples of the silane coupling agent include, but are not limited to, chlorosilanes, epoxysilanes, aminosilanes, and isocyanatosilanes.

  Examples of the monofunctional alcohol include aliphatic monols, alicyclic monols, araliphatic monols, polyoxyalkylene monols, oxycarboxylic acid esters, and the like.

  In the adhesive layer (15, 15 ′) made of such a solventless adhesive, in addition to the above components, a filler, a softener, an antioxidant, a stabilizer, an adhesion promoter, a leveling agent, if necessary. Coloring of antifoaming agents, plasticizers, inorganic fillers, tackifying resins, fibers, usable time extenders, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, fungicides, thickeners, pigments, etc. Various additives such as an agent can be contained.

  The adhesive layer (15, 15 ′) composed of the solventless adhesive as described above may be used in combination with the gas barrier layer (12) composed of the inorganic vapor-deposited layer (13) and the coat layer (14) described above. is important.

  That is, by using a non-solvent type adhesive as the adhesive layer (15, 15 '), there is provided an environmentally friendly packaging material which does not cause contamination such as solvent odor to the contents and does not use a solvent. In addition, a combination of a film having a high gas barrier property and a solventless adhesive while ensuring high adhesive strength by combining with a gas barrier layer (12) composed of an inorganic vapor deposition layer (13) and a coat layer (14). It is possible to suppress spot-like (pear-skin, yuzu-skin) appearance defects that have sometimes been a problem in the past.

  In the laminate of the present invention, by providing an adhesive layer (15) made of a solventless adhesive on the above-mentioned coat layer (14), it is possible to suppress the spot-like defective appearance which has conventionally been a problem. The reason for this cannot be elucidated.

  However, it seems that the following can be guessed.

  The spot-like appearance defect that has been a problem in the past, in order to improve the coatability of the coating solution is a solvent-free adhesive, for example, by reducing the average molecular weight of the polyisocyanate component and the polyol component, the coating solution It is necessary to reduce the viscosity of the adhesive layer. Therefore, the initial cohesive force immediately after coating is small, and curing is required for several days to obtain the adhesive strength by lamination. The fine bubbles and voids contained therein were generated at the interface between the adhesive layer and the gas barrier layer by moving and concentrating and growing.

  On the other hand, the coat layer (14) in the present invention contains a water-soluble polymer having a hydroxyl group and the like, and a part of the reactive hydroxyl groups contained in the water-soluble polymer and the like becomes part of the coat layer ( In the case where it remains near the coating surface of 14), a urethanization reaction occurs with the polyisocyanate component contained in the solventless adhesive applied from above, and the coating layer (14) and the adhesive layer (15) , There is a possibility that a strong adhesion including a crosslinked structure is made.

For this reason, even if the adhesive layer contains fine air bubbles, the interface between the coat layer (14) and the adhesive layer (15) is firmly adhered to, so that the air bubbles move and concentrate during the curing process. It is considered that growth and the like due to growth are unlikely to occur, and spot-like poor appearance is unlikely to occur.

(Base material)
As the base material (16), any material can be used as long as it is the same as that used in conventional packaging bags, and is not particularly limited. From the viewpoint of suitability as a packaging material, a polyester-based polymer, Examples thereof include polyamide polymers and polyolefin polymers.

  Examples of the polyester polymer include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyε-caprolactone, polyhydroxybutyrate, polyhydroxyvalerate, and copolymers thereof.

  Examples of the polyamide polymer include nylon 6, nylon 66, nylon 12, nylon 6,66 copolymer, nylon 6,12 copolymer, metaxylene adipamide / nylon 6 copolymer, and copolymers thereof. Coalescence and the like.

  Examples of the polyolefin-based polymer include low-density polyethylene, high-density polyethylene, linear low-density polyethylene, polypropylene, poly4-methylpentene, cyclic polyolefin, copolymers thereof, and acid-modified products thereof. Can be.

  The material used for the base material (16) may be unstretched or stretched. Further, the base material (16) may be composed of a single layer, or may be composed of a plurality of layers.

  As the substrate (16) in the present invention, a biaxially stretched nylon film (ONY) can be suitably used.

  The surface of such a base material (16) may be subjected to a surface activation treatment such as a corona treatment, a flame treatment, and a plasma treatment.

  The thickness of the base material (16) can be arbitrarily set according to the application, and can be, for example, in the range of 5 to 500 μm.

(Heat fusion layer)
The heat sealing layer (17) is a transparent resin layer having a thermal adhesive property. As a material for the heat-sealing layer (17), a resin film that can be melted by heat and can be mutually bonded can be used. Specifically, for example, low-density polyethylene (LDPE), medium-density polyethylene ( MDPE), high-density polyethylene (HDPE), linear (linear) low-density polyethylene (LLDPE), polypropylene, ethylene-vinyl acetate copolymer, ionomer resin, ethylene-acrylic acid copolymer, ethylene-ethyl acrylate Copolymer, ethylene-methacrylic acid copolymer, ethylene-methyl methacrylate copolymer, ethylene-propylene copolymer, methylpentene polymer, polybutene polymer, polyolefin resin such as polyethylene or polypropylene, acrylic acid, methacrylic acid, Maleic acid, maleic anhydride, fumaric acid, itako Can be used acid-modified polyolefin resin modified with an unsaturated carboxylic acid such as an acid, polyvinyl acetate resins, poly (meth) acrylic resin, a film of resin such as polyvinyl chloride resin.

  In the laminate (10) obtained as described above, a printing ink layer or the like may be interposed between any layers or the like according to the application and requirements.

  The printing layer is formed for practical use as a packaging bag or the like, and various pigments are added to conventionally used ink binder resins such as urethane, acrylic, nitrocellulose, rubber, and vinyl chloride. This is a layer composed of an ink to which an additive such as an extender, a plasticizer, a desiccant, a stabilizer, and the like are added, and on which characters, pictures, and the like are formed. As a forming method, for example, a known printing method such as an offset printing method, a gravure printing method, and a silk screen printing method can be used. The thickness is preferably from 0.1 to 2.0 μm.

(Packaging bag)
A method for manufacturing a package by forming a bag of the laminate (10) of the present invention will be described. For example, a laminate (10) having gas barrier properties produced by the above-described method is used, and the heat of the inner layer is used. With the surfaces of the fusion layer (17) facing each other and folding or overlapping the two sheets, and furthermore, the peripheral end thereof is thermally fused to provide a seal portion, and the liquid in various forms is formed. Filling bags can be manufactured.

  FIG. 2 shows an example of the retort packaging bag (20) manufactured as described above, and a heat-sealed seal portion (21) is provided at a peripheral end of the retort packaging bag (20). Is formed.

  The packaging bag using the laminate (10) of the present invention is not necessarily limited to the structure shown in FIG. 2, and various packaging bags can be manufactured. For example, a side seal type, a two-side seal type Heat sealing by three-sided seal type, four-sided seal type, envelope-attached seal type, gasoline-attached seal type (pillow seal type), pleated seal type, flat bottom seal type, square bottom seal type, etc. Various kinds of packaging bags can be manufactured. In addition, for example, it is also possible to manufacture as various packaging bags such as a self-supporting packaging bag (standing pouch).

  When filling the obtained retort packaging bag with food or the like, heat sterilization or the like is performed.

  Examples of the heat sterilization treatment method include a retort treatment and a boil treatment. In general, retort treatment is a method for pressurizing microorganisms such as mold, yeast, and bacteria in order to preserve foods and the like. Usually, the gas barrier laminate packaging material in which food is packaged is subjected to a pressure sterilization treatment at 105 to 140 ° C. and 0.15 to 0.30 MPa for 10 to 120 minutes.

  The retort apparatus is classified into a steam type using heated steam and a hot water type using heated pressurized water. The retort device is appropriately used depending on sterilization conditions of foods and the like as contents. The boil treatment is a method of performing heat and heat sterilization for preserving foods and the like.

  Usually, although depending on the contents, the gas barrier laminate packaging material packaged with food or the like is subjected to a wet heat sterilization treatment at 60 to 100 ° C. under atmospheric pressure for 10 to 120 minutes. The boiling treatment is usually performed using a hot water tank, and there are a batch type in which the steel sheet is immersed in a hot water tank at a certain temperature and is taken out after a certain period of time, and a continuous type in which the inside of the hot water tank is sterilized by passing through a tunnel.

  By using the laminate of the present invention, even in the post-treatment steps such as the bag making process and the heat sterilization process as described above, hot water resistance, retort treatment, boil treatment, excellent gas barrier properties even when subjected to heating and cooking. In addition, the present invention can provide a laminated body which can be maintained, solves the processing problem in the laminating step of producing the laminated body, has no concern about residual solvent, and has no spot-like defects in appearance.

Hereinafter, the present invention will be described more specifically with reference to Examples. However, the following Examples do not limit the scope of the present invention.

(Example 1)
After forming an inorganic vapor-deposited layer (13) made of aluminum oxide on a PET film by using a vacuum vapor-deposition method, the inorganic vapor-deposited layer (13) contains polyvinyl alcohol as a water-soluble polymer having a hydroxyl group, A coating liquid for a coating layer (14) containing tetraethyl orthosilicate and a silane coupling agent was applied and dried to obtain a PET film having a gas barrier layer (12).

  For the PET film having the gas barrier layer (12) obtained, using the following coating solution 1 as a solventless adhesive, stretched nylon (ONY) as a substrate (16), and a heat-sealing layer ( 17) A laminate sample 1 was obtained by sequentially laminating a sealant film made of unstretched polypropylene (CPP) by a solventless lamination method.

<Coating liquid 1>
Polyol component: Main agent A
(Aliphatic ester adhesive Dick Dry HA Series DIC Corporation)
Polyisocyanate component: Curing agent A
(Aliphatic ester adhesive Dick Dry 2K-SF Series DIC Corporation)

(Example 2)
A laminate sample 2 was obtained in the same manner as in Example 1 except that the following coating liquid 2 was used as the solventless adhesive.

<Coating liquid 2>
Polyol component: Main agent B
(Aliphatic ester adhesive Dick Dry HA Series DIC Corporation)
Polyisocyanate component: Curing agent B
(Aliphatic ester adhesive Dick Dry 2K-SF Series DIC Corporation)

(Example 3)
A laminate sample 3 was obtained in the same manner as in Example 1, except that the following coating liquid 3 was used as the solventless adhesive.

<Coating liquid 3>
Polyol component: Main agent C
(Aliphatic ester adhesive Takelac series Mitsui Chemicals, Inc.)
Polyisocyanate component: Curing agent C
(Aliphatic ester adhesive Takenate series Mitsui Chemicals, Inc.)

(Example 4)
A laminate sample 4 was obtained in the same manner as in Example 1 except that the following coating liquid 4 was used as the solventless adhesive.

<Coating liquid 4>
Polyol component: Main agent D
(Aliphatic ester adhesive Takelac series Mitsui Chemicals, Inc.)
Polyisocyanate component: Curing agent D
(Aliphatic ester adhesive Takenate series Mitsui Chemicals, Inc.)

  Each of the laminate samples 1 to 4 obtained as described above was subjected to a retort treatment at a temperature of 130 ° C. for 60 minutes, and the following evaluation was performed before and after the retort treatment.

(Lamination strength test)
For each of the laminate samples 1 to 4 obtained in Examples 1 to 4, the lamination strength between the coat layer / ONY and between the ONY / CPP before and after the retort treatment was measured using a Tensilon universal testing machine RTC- It was measured using 1250 (based on JIS Z1707).

(Visual inspection)
About each laminated body sample 1-4 obtained by Examples 1-4, before and after the said retort processing, the visual inspection was performed about the external appearance, and it was determined whether there was a spot-like (pear-skin, citron-skin) defective portion. , Evaluation was carried out.

: No spot-like defective part X: Spot-like defective part present Table 1 shows the results of the above evaluations.

  From the results shown in Table 1, by using a gas barrier layer composed of an inorganic vapor-deposited layer and the following coat layer in combination with a solventless adhesive composed of a polyol component and a polyisocyanate component, spots were observed both before and after the retort treatment. It was found that a laminate having a laminate strength sufficient for use as a packaging bag for a retort without the occurrence of a defective appearance portion in a shape was obtained.

(Coat layer)
One of the silicon compound represented by the following general formula (1) and its hydrolyzate, one of the silicon compound represented by the following general formula (2) and its hydrolyzate, and water-soluble having a hydroxyl group It is obtained by applying and drying a coating solution containing a polymer.

Si (OR ¹ ) ₄ ... (1)
(R ² Si (OR ³ ) ₃ ) _n (2)
(However, R ¹ and R ³ are CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OCH ₃ , and R ² is an organic functional group)

DESCRIPTION OF SYMBOLS 10 ... Laminated body 11 ... Surface base material 12 ... Gas barrier layer 13 ... Inorganic vapor deposition layer 14 ... Coat layer 15, 15 '... Adhesive layer 16 ... Substrate 17 ... Heat fusing layer 20 ... Retort packaging bag 21 ... Seal part

Claims (4)

A surface laminate, a gas barrier layer, an adhesive layer, a substrate, an adhesive layer, a laminate formed by laminating a heat sealing layer,
The gas barrier layer comprises an inorganic vapor-deposited layer and a coat layer,
The adhesive layer is a solventless adhesive layer,
The coating layer includes one of a silicon compound represented by the following general formula (1) and a hydrolyzate thereof, one of a silicon compound represented by the following general formula (2) and a hydrolyzate thereof, and A laminate comprising a water-soluble polymer having a hydroxyl group.
Si (OR ¹ ) ₄ ... (1)
(R ² Si (OR ³ ) ₃ ) _n (2)
(However, R ¹ and R ³ are CH ₃ , C ₂ H ₅ , or C ₂ H ₄ OCH ₃ , and R ² is an organic functional group) The solventless adhesive layer contains a polyisocyanate component and a polyol component,
The polyisocyanate component contains an araliphatic diisocyanate component,
2. The laminate according to claim 1, wherein the polyol component is partially modified with a terminal acid. 3.   3. The laminate according to claim 1, wherein the inorganic vapor-deposited layer contains one or more of aluminum oxide and silicon oxide. 4.   A packaging bag for a retort, comprising the laminate according to any one of claims 1 to 3.

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