JP2001199016A - Gas barrier laminate - Google Patents

Abstract

(57) Abstract: The present invention provides a gas barrier laminate having excellent gas barrier properties and coating strength. A gas barrier laminate having a gas barrier layer formed on at least one surface of a support, wherein the gas barrier layer is formed of one or more silicic acid condensates selected from colloidal silica or alkali metal silicate, A gas barrier laminate containing a pigment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas barrier laminate which is suitable as various packaging materials, molded articles or molding materials.

[0002]

2. Description of the Related Art In packaging materials used for packaging foods and the like, gas barrier properties, particularly oxygen, water vapor, carbon dioxide and aroma (aroma,
The flavor quality is an important quality. Packaging materials using such barrier materials include confectionery bags, bonito packs, retort pouches, meat packaging such as ham and sausage, seafood packaging, dairy packaging, miso packaging,
It is used in many fields such as packaging of tea and coffee, carbon dioxide beverage containers, packaging of cosmetics, agricultural chemicals and pharmaceuticals.

On the other hand, polyolefin resins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyamide resins such as nylon 6 and nylon 66, polystyrene, ethylene vinyl acetate copolymer and the like Thermoplastic resins are widely used as packaging materials because of their excellent strength, heat resistance, transparency and the like.

[0004]

However, when a film made of these thermoplastic resins is used as a packaging material,
Since the gas barrier property is insufficient, a method of laminating with a thermoplastic resin having gas barrier property, an aluminum foil, an aluminum vapor-deposited film, a silicon vapor-deposited film, or the like to form a packaging material is generally used.

[0005] Thermoplastic resins having high gas barrier properties include polyvinyl alcohol (PVA), ethylene vinyl alcohol (EVOH, saponified ethylene-vinyl acetate copolymer), polyalcohol (reduced polyketone), and vinylidene chloride (PVDC). ), Etc., but resins exhibiting barrier properties due to hydrogen bonding by hydroxyl groups such as PVA and EVOH are highly humid (for example, 20 ° C. 80%
(RH or higher), there is a problem that the barrier property is rapidly reduced. Further, PVDC is a chlorine compound, and it is a recent situation to try to avoid using it as a packaging material as much as possible because of increasing awareness of environmental issues. On the other hand, a packaging material using an aluminum foil or an aluminum vapor-deposited film has a drawback that a metal detector cannot be used or is opaque, in addition to environmental problems, and is used only for specific packaging. Further, a film on which an inorganic oxide such as silicon oxide or aluminum oxide is vapor-deposited has excellent gas barrier properties, but has a disadvantage of high cost due to vapor deposition. Also,
There is a problem that cracks occur in the vapor deposition layer due to bending or twisting, and the gas barrier properties are reduced.

In contrast to the prior art described above, there is a method in which an aqueous liquid comprising an alkali silicate solution and a coupling agent is applied to the surface of a polymer molded product to form a thin film, thereby obtaining a gas barrier laminate. JP-A-8-238711). This method has the advantage that the gas barrier laminate can be manufactured at low cost without performing operations such as vapor deposition, but has the problem that the gas barrier properties may still be insufficient and the strength of the coating film is weak.

On the other hand, as a method of developing gas barrier properties,
There is a method of dispersing and kneading a flattened inorganic material in a resin. For example, Japanese Patent Application Laid-Open No. 62-148532 discloses a method.
A coating liquid composition consisting of 25 parts by mass of mica fine powder and 60 parts by mass of dimethylformamide was added to 100 parts by mass of a polyurethane resin solution having a concentration of 30% by mass using 1,6-hexane polycarbonate diol on a release substrate. A production method of coating, drying, and then peeling off from a substrate is described. JP-A-64-043554 discloses that mica having an average length of 7 μm and an aspect ratio of 140 is added to a methanol aqueous solution of an ethylene / vinyl alcohol copolymer, and this is poured into cold water to precipitate. Filtration, drying, pelletizing, and then obtaining a film are described. Further, JP-A-3-93542 discloses that a coating composition in which a silyl group-containing modified polyvinyl alcohol and a synthetic hectorite are in a mass ratio of 50:50 is applied on biaxially stretched polyethylene terephthalate (OPET), A method of drying and heat treatment (130 to 150 ° C.) is described. JP-A-7-251489 exemplifies a gas barrier layer having a resin having a high hydrogen bonding property and an inorganic layered compound. However, films obtained by these techniques cannot always be said to have satisfactory gas barrier properties particularly under high humidity conditions. In particular, when cross-linking is performed to compensate for the lack of water resistance of the resin, the orientation of the plate-like pigment is disturbed, and the density of the resin is reduced, so that it is easy to create a space for transmitting oxygen molecules. That's not something. Therefore, an object of the present invention is to provide a gas barrier laminate having excellent gas barrier properties, particularly gas barrier properties under high humidity conditions, and excellent coating film strength.

[0008]

The present invention has the following arrangement to solve the above-mentioned problems. 1: In a gas barrier laminate having a gas barrier layer formed on at least one surface of a support, the gas barrier layer has
A gas barrier laminate comprising one or more silicic acid condensates selected from colloidal silica or alkali metal silicate, and a tabular pigment. 2: The gas barrier laminate according to 1, wherein the alkali metal silicate contains lithium silicate. 3: The gas-barrier laminate according to 1 or 2, wherein the particle diameter of the tabular pigment is 10 nm to 5 μm. 4: The gas barrier laminate according to any one of 1 to 3, wherein the tabular pigment is an inorganic layered compound. 5: The gas barrier laminate according to 4, wherein the inorganic layered compound is a smectite clay. 6: The gas barrier laminate according to any one of 1 to 5, wherein the mass mixing ratio of the silicic acid condensate and the tabular pigment is from 95/5 to 5/95. 7: The gas barrier laminate according to any one of 1 to 6, wherein the support is a synthetic resin film. 8: The gas barrier laminate according to 7, wherein the support is a film mainly composed of at least one resin selected from a polyolefin resin, a polyester resin and a polyamide resin. 9: The gas barrier laminate according to 7, wherein the support is a polypropylene resin. 10: The gas barrier laminate according to 7, wherein the support is a laminated film formed by laminating one or more resin layers containing a polyamide resin or a polyester resin on a polyolefin resin layer. 11: The gas barrier laminate according to 7 to 10, wherein the support has a vapor deposition layer, and the gas barrier layer is formed on the vapor deposition layer. 12: The gas-barrier laminate according to any one of 1 to 11, wherein a heat-sealing resin layer is formed on at least one surface. 13: The gas barrier laminate according to any one of 1 to 6, wherein the support is a molded product formed of a material selected from a synthetic resin, glass, and metal.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In a first aspect of the present invention, in a gas barrier laminate having a gas barrier layer formed on at least one surface of a support, the gas barrier layer is formed of colloidal silica or one or more silicate condensates selected from alkali metal silicates. And a plate-like pigment. The support in the present invention is a film or plastic molded product, glass,
Refers to metals such as iron. Further, the gas barrier layer in the present invention contains a silicic acid condensate and a tabular pigment. The term "plate-like pigment" refers to a pigment having a generally flat property and a ratio of the major axis to the thickness (aspect ratio) of 2 or more. When these silicic acid condensates are combined with a flat pigment, gas molecules entering the gas barrier layer are hindered by the crystallinity of the flat pigment and have a curved effect in which the transmission path is bent. Furthermore, the silicic acid condensate has the property that it is easy to make the primary particles as small as about nanometers and has the property of packing very densely.The primary particles themselves are amorphous, but the gas molecules, especially oxygen and water vapor, Do not transmit such molecules. Further, the voids formed in the film formed by the particles of these silicic acid condensates also form a strong film because fusion occurs as the silanol groups on the surface of the silicic acid proceed to condense.

The silicic acid condensate in the present invention refers to colloidal silica or an alkali metal silicate. Colloidal silica is prepared by passing sodium silicate through a cation ion exchange resin layer, adjusting the pH with an alkali, and then heating to generate colloidal silica nuclei. Is slowly added dropwise. If the dropping speed is increased rapidly, condensation rapidly proceeds, and aggregation is generated, resulting in a porous structure, which is not preferable. When the solution is slowly dropped, monomers are sequentially deposited on silanol groups on the nucleus surface, and particles grow. By adjusting the pH appropriately and slowing down the dropping rate, it is possible to grow from several nm to several μm. On this occasion,
The coexistence of a salt is not preferable because it is likely to be aggregated. The particle diameter of the colloidal silica used in the present invention is several n
Those having a diameter of m to several hundreds of nm are preferred. Further, by using a combination of colloidal silicas having different particle diameters, the filling rate of the gas barrier layer can be increased. Further, in order to promote fusion between the colloidal silica particles, the surface of the gas barrier layer can be treated with an acid.

Next, the alkali metal silicate is M ₂ O · n
It is a compound represented by SiO ₂ (M is an alkali metal salt, n> 0). The molar ratio of M ₂ O to SiO ₂ SiO ₂ / M ₂ O =
n is also called a diatom ratio, and the molar ratio n is preferably from 0.4 to 10, more preferably from 1 to 8, and still more preferably from 2 to 8.
6. When the molar ratio n is less than 0.4, the film-forming ability due to the condensation of silicic acid is reduced and the barrier properties are reduced, and the moisture resistance and water resistance are reduced due to the excessive content of the alkali metal salt. If the molar ratio exceeds 10 and becomes large, it is not preferable because defects of the coated surface such as generation of cracks occur. The alkali metal M of the alkali metal silicate used in the present invention is an alkali metal such as lithium, sodium or potassium, or a cationic ion such as ammonia. The alkali metal silicate is usually handled as a concentrated aqueous solution.
A sodium silicate solution in which the alkali metal is sodium (sodium silicate solution) is generally called water glass, and powdered sodium silicate is also called anhydrous water glass. Also,
What is in an intermediate state between anhydrous water glass and water glass (alkali silicate containing a small amount of water) is water water glass. Sodium silicate has a molar ratio of 0.5
Sodium orthosilicate _{(Na 2 O · 1 / 2SiO} 2 or Na ₄ SiO _4), sodium sesquicarbonate silicate molar ratios 0.67 (3Na ₂ O · 2SiO ₂ or Na ₆ Si
₂ O ₇ ), sodium metasilicate (Na ₂ OS
iO ₂ or Na ₂ SiO ₃ ), and sodium disilicate (Na ₂ O · 2SiO ₂ or Na ₂ Si) having a molar ratio of 2
₂ O ₅ ), sodium tetrasilicate with a molar ratio of 4 (Na ₂ O · 4S)
iO ₂ or Na ₂ Si ₄ O ₉ , also known as sodium silicate 4)
However, in many cases, the composition of sodium silicate is not constant. Or Japanese Industrial Standard JIS-K
Sodium silicate No. 1 (molar ratio 2) specified in -1408,
No. 2 (molar ratio 2.5), No. 3 (molar ratio 3), one type of sodium metasilicate, and two types of sodium metasilicate. There are various aqueous solutions of sodium silicate depending on the difference in silicon dioxide content, sodium oxide content, molar ratio, Baume degree at 15 ° C. (Baume degree is an index of specific gravity), viscosity, and the like.

In the present invention, these physical properties are not particularly limited. Generally, commercially available sodium silicate has a Baume degree at 15 ° C. of 5 to 70 and a silicon dioxide content (mass).
20-40%, sodium oxide content (mass) 5-30
%, Viscosity (20 ° C.) 0.5 to 2000 poise. Further, an aqueous alkali silicate solution in which dehydrated powdery sodium silicate is dissolved in water may be used.

Potassium silicate wherein the alkali metal salt is potassium
There are various compositions of um, but as an example
Potassium metasilicate (K_TwoO ・ SiO_Two), Potassium silicate
(K_TwoO ・ 4SiO_Two・ H_TwoO, also known as potassium disilicate
). Silica whose alkali metal salt is lithium
Even when the composition of lithium oxide is not constant,
In many cases, lithium orthosilicate (Li_TwoO1 / 2Si
O_Two), Lithium metasilicate (Li_TwoO ・ SiO_Two), Meta
Lithium silicate hydrate, hexalithium orthodisilicate (Li _Two
O.2 / 3SiO_Two)and so on. These alkali silicates
The degree of condensation varies depending on the molar ratio of the metal salt, and the particle size
Will also be different. The size of the liquid decreases as the molar ratio decreases.
It is difficult to determine clearly because the solubility in
Although not possible, the light scattering method estimates
It can be densely packed as a barrier layer. Ma
In addition, the formed particles are more easily condensed than colloidal silica.
It is preferable because a dense coating can be formed.

Such an aqueous solution or powder of an alkali metal silicate can be used at an arbitrary concentration by adding water. The preferred concentration range is 0.1 to 50% by mass, more preferably 0.5 to 30% by mass, and even more preferably 1 to 50% by mass.
20% by mass. When the concentration is less than 0.1% by mass,
After the coating, the amount of water evaporated during drying becomes very large, so that the productivity is greatly reduced. When the concentration exceeds 50% by mass, the viscosity of the aqueous solution becomes very large, and the coating suitability is lowered.

The paint containing an alkali metal silicate of the present invention may be composed of the aqueous solution of the alkali metal silicate or a mixture of two or more alkali metal silicates. Further, in the solution, resins such as synthetic resin emulsions, water-soluble resin emulsions and resin dispersions, color adjusting agents, viscosity adjusting agents, inorganic pigments, organic pigments (plastic pigments), and various curing agents for alkali metal silicates ( Inorganic salts such as carbonates, sulfates, hydrochlorides, nitrates, phosphates, and silicates; and mineral acids such as nitric acid, phosphoric acid, hydrochloric acid, and sulfuric acid; and organic acids such as lactic acid, humic acid, oxalic acid, boric acid, and gallic acid. Acid, phosphate compounds such as polyaluminum chloride, aluminum dihydrogen polyphosphate, sodium hexametaphosphate, metal oxides such as zinc oxide and titanium oxide, and metal hydroxides such as aluminum hydroxide and magnesium hydroxide), A coupling agent such as a silane coupling agent or an aluminum coupling agent may be included.

The silicic acid condensate used in the present invention has a low molecular weight silicate compound which elutes when a gas barrier layer formed by coating and drying on a support is poured out with water,
Specifically, the content is preferably 30% by mass or less based on the silicic acid condensate of the entire gas barrier layer. In general, silicic acid often contains low molecular weight monomers, dimers, tetramers, octomers, etc., and these low molecular weight silicate compounds are highly reactive and easily react with the silica particles to promote the growth of the silica particles. It is preferred in the drying step for forming a layer. However, after the gas barrier layer is formed on the support, if the low molecular weight silicate compound is present in the coating layer in a large amount, if the coating is left for a long time after the coating, condensation will proceed too much and the film will shrink, The presence of an acidic silicate compound is not preferred because the water resistance of the gas barrier layer is greatly reduced. Therefore, the water-soluble silicate compound eluted in a solution obtained by extracting the gas barrier layer obtained by the present invention with ion-exchanged water at 25 ° C. for 24 hours was determined by the molybdenum blue method (Analytical Chemistry Handbook, revised 4th edition, p. 266, Japan Society for Analytical Chemistry) When quantified by, the amount of the low molecular weight silicate compound that reacts with molybdic acid is preferably 30% by mass or less, more preferably 15% by mass or less, based on the silicic acid condensate in the gas barrier layer. To reduce the amount of the water-soluble low-molecular silicate compound, increase the drying temperature of the coating layer, adopt a film formation promoting method such as infrared drying or UV irradiation, or add various crosslinking agents to the gas barrier layer. That can be achieved.

A second aspect of the present invention is the gas barrier laminate according to the first aspect, wherein the alkali metal silicate contains lithium silicate. Among the alkali metal silicates, lithium silicate has an ionic radius of lithium smaller than an ionic radius of sodium of sodium silicate and potassium of potassium silicate, so that when silicic acid is condensed, it is easily taken into a silicate condensed network. Which are trapped in the silicic acid condensate of the above and are difficult for ions to move. For this reason, the water resistance of lithium silicate is much higher than that of sodium silicate or potassium silicate, which is preferable. Of course, when the molar ratio is high, the alkali content is small and the water resistance is good, but cracks and cracks are easily generated when the gas barrier layer is formed, so that it may be appropriately selected together with the selection of the tabular pigment. preferable.

A third aspect of the present invention is that the tabular pigment has a particle diameter of 1
The gas barrier laminate according to any one of the first and second aspects of the present invention, which has a thickness of 0 nm to 5 μm. The particle size of the tabular pigment used in the present invention is preferably from 10 nm to 5 μm.
m, more preferably about 20 nm to 1 μm. 1
If it is less than 0 nm, it is difficult to obtain flatness, it is difficult to arrange the coating layer in parallel with the support during drying, and it is difficult to exhibit a curved path effect. On the other hand, if the thickness exceeds 5 μm, the film-forming properties are undesirably reduced.

The tabular compound that can be used in the third aspect of the present invention is not particularly limited as long as it has a particle size of from 10 nm to 5 μm, but from the viewpoint of the transparency of the gas barrier laminate, the particle size is preferably It is preferably 1 μm or less. Further, when the gas barrier laminate is a film and is used for applications where transparency is important (for example, food applications), the particle size is particularly preferably 0.5 μm or less.
Note that the transparency is 8 in total light transmittance at a wavelength of 500 nm.
It is preferably at least 0%, more preferably at least 85%. Such transparency can be suitably measured with a commercially available spectrophotometer (eg, Shimadzu self-recording spectrophotometer UV-3100PC type, manufactured by Shimadzu Corporation). Next, from the viewpoint of gas barrier properties, the aspect ratio of the tabular pigment is 20.
It is preferable that it is above. When the aspect ratio is less than 20, the gas barrier property may be insufficiently developed depending on the application. On the other hand, it is technically difficult to obtain an inorganic layered compound having an aspect ratio of more than 1,000, and it is expensive. In terms of manufacturability, this aspect ratio is 100
It is preferably 0 or less. The particle size of such a plate-like pigment can be measured by a light scattering measuring device. In the present invention, the average particle size was determined by direct observation using a transmission electron microscope. The aspect ratio was determined by searching for a rod-like material other than scales in the field of view of a transmission electron microscope.

A fourth aspect of the present invention is the gas barrier laminate according to any one of the first to third aspects, wherein the plate-like pigment is an inorganic layered compound. The tabular pigment used in the fourth aspect of the present invention refers to an inorganic layered compound having a layered structure in which unit crystal layers are stacked on each other. In other words, a “layered compound” is a compound or substance having a layered structure, and a “layered structure” is a surface in which atoms are strongly bonded by covalent bonds or the like and densely arranged, such as van der Waals forces. Refers to pigments having a high flatness and a structure stacked in parallel with each other due to a weak bonding force or bonded with ions. Specific examples of the inorganic layered compound include graphite, phosphate derivative-type compounds (zirconium phosphate compounds), chalcogenides [Group IV (Ti, Zr, Hf), Group V (V, Nb, T
a) and Group VI (Mo, W) has dichalcogen products of, the formula MX ₂ (wherein, X is a chalcogen (S, Se, Te) shows a). Further, clay minerals and the like can be mentioned.

The clay mineral generally has a two-layered structure having an octahedral layer made of aluminum, magnesium or the like as a central metal on the tetrahedral layer of silica. It is classified into a type having a three-layer structure in which an octahedral layer made of magnesium or the like as a central metal is narrowed from both sides. The former two-layer structure type includes kaolinite group and antigolite group, and the latter three-layer structure type includes smectite group, vermiculite group and mica group depending on the number of interlayer cations. Can be.

More specifically, these clay minerals include kaolinite, dickite, nacrite, smectite, halloysite, antigorite, chrysotile, pyrophyllite, tetrasilyl mica, sodium teniolite, muscovite, Margarite, talc,
Vermiculite, phlogopite, zansophyllite, chlorite, synthetic mica and the like can be mentioned. Among these, smectite clay is composed of crystals having a three-layer structure, and the following compounds are known. 1 Montmorillonite X _0.33 (Al _1.67 Mg _0.33 ) Si ₄ O
₁₀ (OH) ₂・ nH ₂ O 2 Beiderite X _0.33 (Al ₂ ) (Al _0.33 Si _3.67 ) O
₁₀ (OH) ₂・ nH ₂ O 3 Nontrolite X _0.33 (Fe ₃ ⁺² ) (Al _0.33 Si _3.67 )
O ₁₀ (OH) ₂・ nH ₂ O 4 Saponite X _0.33 (Mg ₃ ) (Al _0.33 Si _3.67 ) O
₁₀ (OH) ₂・ nH ₂ O 5 Iron saponite X _0.33 (Mg, Fe) ₃ (Al _0.33 S
i _3.67 ) O ₁₀ (OH) ₂・ nH ₂ O 6 Hectorite X _0.33 (Mg _2.67 Li _0.33 ) Si ₄ O ₁₀
(OH) ₂・ nH ₂ O 7 Sauconite X _0.33 (Mg, Zn) ₃ (Al _0.33 S
i _3.67 ) O ₁₀ (OH) ₂ · nH ₂ O 8 Stipnsite X _{0.33 / 2} (Mg _2.97 ) Si ₄ O ₁₀ (OH) ₂
・ NH ₂ O 9 Hectite X _0.33 (Mg _2.67 Li _0.33 ) Si ₄ O
₁₀ (OH, F) ₂ .nH ₂ O X is a metal such as K, Na, ＣａCa, ＭｇMg or the like, but a commercially available product is Na. These smectite clays are fine powders of pale yellow or white, having a size of several μm or less, and swell in water to form a unique colloidal structure. For example, montmorillonite has a three-layer structure in which an alumina layer is sandwiched between two silicas as one unit, and the flakes are connected via water.In an aqueous solution, the water between the flakes causes the flakes to fall apart. Become.

In general, smectite clay easily forms a colloidal dispersion liquid, ie, a sol, when dispersed in water. However, as the concentration increases, it becomes easier to form a gel and exhibits remarkable thixotropic properties. For this reason, it is difficult to prepare a smectite clay dispersion having a high concentration. But,
The addition of a deflocculant is preferable because a stable fluid dispersion (sol) is obtained and the viscosity is reduced. Examples of the deflocculant include polyvalent phosphates such as hexametaphosphate and polyphosphate (such as sodium pyrophosphate). Particularly, sodium pyrophosphate is preferred.

A fifth aspect of the present invention is the gas barrier laminate according to the fourth aspect, wherein the inorganic layered compound is a smectite clay. When an inorganic layered compound is used as a tabular pigment, it is important that the solvent sufficiently penetrates between the layers and swells. However, smectite clay has a particularly strong tendency and tends to become isolated particles. For this reason, it is easy to disperse with the alkali silicate condensate, and a uniform coating film without aggregation is obtained.

A sixth aspect of the present invention is the first to fifth aspects of the present invention, wherein the weight ratio of the silicic acid condensate to the tabular pigment is from 95/5 to 5/95.
6. The gas barrier laminate according to any one of 5. Among the tabular pigments, smectite clay such as montmorillonite can easily form a film due to its tabularity and surface charge. However, the strength of the coating is low and it is necessary to reinforce it with a silicic acid condensate. On the other hand, if the silicic acid condensate alone is used, the coating is liable to crack with the condensation, but the addition of a tabular pigment can significantly reduce the occurrence of cracks. As described above, the silicic acid condensate and the tabular pigment work to compensate for each other. For this reason, the ratio of the silicic acid condensate to the tabular pigment can take a wide range. However, from the viewpoint of the strength of the gas barrier film, the greater the ratio of the silicate condensate, the higher the practicality, and the ratio of the silicate condensate to the tabular pigment is preferably about 90/10 to 40/60.

A seventh aspect of the present invention is the gas barrier laminate according to any one of the first to sixth aspects, wherein the support is a synthetic resin film. Examples of the synthetic resin film usable in the present invention include polyolefin resins such as polyethylene and polypropylene, and polyethylene terephthalate (PE).
T), films of polyester resins such as polyethylene naphthalate (PEN), polysuccinate, polylactic acid, polyamide resins such as nylon 6 and nylon 66, and thermoplastic resins such as polystyrene and ethylene vinyl acetate copolymer. Can be used. Also, a laminated film obtained by laminating a film made of these resins by an arbitrary method as necessary can be used. Further, as the above-mentioned film, a uniaxially stretched or biaxially stretched film can be used. Conventionally, when a functional layer is formed thereon using a thermoplastic resin or the like as a support, in order to improve the adhesion with the support, a chlorinated acid solution treatment, a corona discharge treatment,
A polar group is imparted to the support surface by a physical treatment or a chemical treatment such as a flame treatment, a silane coupling agent treatment, a titanium coupling agent treatment, an ionomer layer formation treatment, a polycation treatment, and the substrate surface is made hydrophilic. Methods are known. Examples of the hydrophilic group that can be introduced on the surface of the substrate include a hydroxyl group, a carbonyl group, a carboxyl group, and an amino group. By making the surface of the base material hydrophilic by such a method, it is possible to prevent the occurrence of repelling and bumps when applying a gas barrier paint, and to perform the surface treatment of the base material, And appearance.

In the present invention, the above-mentioned physical treatment or chemical treatment is applied to a support, and a hydrophilic polar group such as a hydroxyl group, a carbonyl group, a carboxyl group or an amino group is imparted to the surface of the support. A layer containing a nitrogen-containing compound that reacts with the substance is formed as a first layer on the surface of the support.

An eighth aspect of the present invention is the gas barrier property according to the seventh aspect, wherein the support is a film containing as a main component at least one resin selected from a polyolefin-based resin, a polyester-based resin, and a polyamide-based resin. It is a laminate. The polyester resin used in the present invention contains a repeating ester bond in the main chain, and the ester bond has dehydration condensation of dicarboxylic acid and diol, ring opening dehydration condensation of cyclic ester, and has a hydroxyl group and carboxylic acid in the molecule. Although it is obtained by a dehydration condensation reaction, it is usually produced industrially through a polycondensation step after an esterification or transesterification step. Depending on the selection of the monomer, there are a saturated or unsaturated aliphatic polyester, an aromatic polyester, a polyester composed of an aliphatic and an aromatic, and the like. More specifically, examples include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), polysuccinate, and polylactic acid. These resins may be used as a mixture, or a polyester partially modified with another monomer may be used.

The polyamide resin used in the present invention is a polymer having an amide bond repeatedly in the main chain, and is obtained by a condensation reaction between an amine and a carboxylic acid. Such polyamide resins include nylon 6, nylon 7, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, nylon 612 and the like. Also, these resins may be used in combination.
A polyester modified with some other monomer may be used. These polyester-based resins and polyamide-based resins are excellent in application suitability and adhesion of a coating film to an aqueous paint containing an alkali metal silicate. This is presumably because a hydrophilic portion such as an ester bond or an amide bond in the resin or a hydrophilic group such as a hydroxyl group, a carboxylic acid group, an amino group, or an amide group has a high affinity for alkali silicate. Also,
Since such a resin has a rigid molecular structure, it is characterized in that the rigidity of the film is higher than that of the polyolefin resin.

The polyolefin resin includes linear low density polyethylene (LLDPE) and low density polyethylene (LDO).
E), medium density polyethylene (MDPE), high density polyethylene (HDPE), polypropylene (PP), ethylene-α olefin copolymer, and the like. Polyolefin-based resins are excellent in heat sealability, strength, and cost, and are therefore consumed in large quantities as packaging materials.

A ninth aspect of the present invention is the gas barrier laminate according to the seventh aspect, wherein the support is a polypropylene resin. Polypropylene-based resins have higher transparency and rigidity than polyethylene-based resins, are less expensive than polyester-based resins and polyamide-based resins, and are preferably used for packaging applications and the like. In particular, a single package having a thickness of about 20 μm to 50 μm is usually used alone, and a composite film can be formed by coextrusion or dry lamination with a functional resin film described below.

In a tenth aspect of the present invention, the support is a laminated film formed by laminating one or more resin layers containing a polyamide resin or a polyester resin on a polyolefin resin layer. It is a gas barrier laminate. Polyamide resins are preferred because of their good piercing properties. Polyester resins are preferred because of their good printability and surface gloss. These layers may be dry-laminated in a separate step as the outer layer of the gas barrier laminate of the present invention,
It is also possible to form a composite film in which multiple layers are formed by co-extrusion. In addition, a gas barrier layer can be formed by previously laminating on a support using a polyolefin-based resin as a support.

An eleventh aspect of the present invention is the seventh aspect of the present invention, wherein the support has a vapor deposition layer and a gas barrier layer is formed on the vapor deposition layer.
10. The gas barrier laminate according to any one of claims 10 to 10. In an eleventh aspect of the present invention, a gas barrier layer is formed after forming a metal or metal oxide vapor deposition layer in advance. The metal or metal oxide forming the deposited layer is not particularly limited, but is preferably stable in the air, and aluminum or the like whose surface is oxidized and stabilized after the deposited layer is preferably used. As the metal oxide, aluminum oxide, silicon oxide, titanium oxide, zinc oxide and the like are preferable, and the oxidation state may be various. The thickness of these metal or metal oxide deposited layers is preferably 1 nm or more and 1000 nm or less. It is more preferably from 10 nm to 300 nm.
The method for forming a metal or metal oxide deposited film is not particularly limited, but may be a CVD method, in addition to a general vacuum deposition method,
A sputtering method or the like is used. Although there is no particular limitation on the synthetic resin film on which the deposited layer of metal or metal oxide is formed, biaxially stretched polyethylene terephthalate,
Biaxially oriented nylon, biaxially oriented polypropylene and the like are preferably used. A gas barrier paint containing a flat pigment and a silicate condensate is applied on the above-mentioned vapor-deposited layer, followed by drying, heat treatment and the like. The gas barrier layer of the present invention is formed. Further, the interface between the gas barrier layer of the present invention and the metal or metal oxide deposited layer may be treated with a corona treatment or an anchor coat agent.

A twelfth aspect of the present invention is the gas barrier laminate according to any one of the first to eleventh aspects, wherein a heat-sealing resin layer is formed on at least one surface. Examples of the heat-sealing resin layer include polyolefin resins such as polyethylene (low density, high density), ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-hexene copolymer, and ethylene-octene copolymer. , Polypropylene, ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ionomer resin and the like are preferably used. These heat seal layers are used by being laminated on at least one surface of the gas barrier laminate. For example, a heat-sealing layer may be formed on the gas barrier layer to form a lid for a cup container, or a heat-sealing layer may be formed on both sides of the gas-barrier laminate to form a bag-like container.

A thirteenth aspect of the present invention is that the support is made of a synthetic resin,
The gas barrier laminate according to any one of the first to sixth aspects of the present invention, which is a molded body formed of a material selected from glass and a metal. By forming the gas barrier layer of the present invention on the surface of a molded product, that is, a surface of a bottle, a container, a tray, a can, or the like, it becomes possible to impart a gas barrier property that cannot be achieved with a support material. In each of the present inventions as described above, an adhesive layer may be provided between the respective layers, if necessary. In particular,
It is preferable to provide an anchor layer between the support and the gas barrier layer. The anchor layer is a general method used to improve the adhesion between the support film and the gas barrier layer, and has a reactive coating layer such as polyethyleneimine, isocyanate, urethane, epoxy, or a polar group. It is formed with a polyester resin layer and the like. Of course, it is also effective to apply a treatment for forming an active group on the film surface in advance, such as a corona treatment, a plasma treatment, a flame treatment, etc., and these treatments may be considered as an anchor layer. Can also be formed.

The present invention relates to the use of the above-mentioned gas barrier laminate for packaging, and for food applications, such as miso, pickles, side dishes, baby food, tsukudani, konjac, chikuwa, kamaboko, processed fishery products , Meatballs, hamburgers, genghis khan, ham, sausages, other processed meat products, green tea, coffee, black tea, bonito, oily confectionery such as kelp, potato chips and butter peanuts, rice crackers, biscuits, cookies, cakes, buns, castella It is used for cheese, butter, cut rice cake, soup, sauce, ramen and the like. In addition to pet foods, agricultural chemicals, fertilizers, infusion packs, etc., those used for a wide range of applications such as semiconductor packaging, oxidizing chemical packaging, precision material packaging, and other industrial material packaging such as medical, electronic, chemical, mechanical, etc. It is.

In the present invention, a molded article can be used as a support, and a gas barrier layer is formed on the surface of a bottle, box, tray or the like molded from PET, PEN, polycarbonate resin, glass, various metals and the like. Including things.

Further, each layer of the support of the present invention may contain an antioxidant, a weather stabilizer, a light stabilizer, an antistatic agent, a pigment, a dye,
Plasticizers, flame retardants, and inorganic fillers such as silica, alumina, calcium carbonate, talc, kaolin, clay, zeolite, mica, carbon black, and glass fibers may be included. Further, in order to further improve the adhesion of the coating film to the surface of the support, an anchor coat agent such as a polyethyleneimine-based, isocyanate-based, urethane-based, or acrylic-based coating may be used, and a dried support may be used.

In addition, a resin can be added to the gas barrier layer of the present invention as long as its properties are not impaired. Although the resin used in the present invention is not particularly limited, for example, polyvinyl alcohol (PVA), ethylene-vinyl alcohol copolymer (EVOH), polyvinylidene chloride (PVDC), polyacrylonitrile (PAN), polysaccharide, polyacryl Acids and esters thereof. Among them, those having a hydrogen-bonding or ionic-bonding functional group are preferable.Examples of the hydrogen-bonding group include a hydroxyl group, an amino group, a thiol group, a carboxyl group, a sulfonic acid group, and a phosphoric acid group. Include a carboxylate group, a sulfonate ion group, a phosphate ion group, an ammonium group, a phosphonium group and the like. More preferred examples include a hydroxyl group, an amino group, a carboxyl group, a sulfonic acid group, a carboxylate group, a sulfonic acid ion group, and an ammonium group.

As specific examples, for example, polyvinyl alcohol, an ethylene-vinyl alcohol copolymer having a vinyl alcohol fraction of 41 mol% or more, hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose, amylopectin, pullulan, curdlan, xanthan Polysaccharides such as, chitin, chitosan, cellulose, pullulan, chitosan, etc., polyacrylic acid, sodium polyacrylate, polybenzenesulfonic acid, sodium polybenzenesulfonate, polyethyleneimine, polyallylamine, its ammonium salt polyvinyl thiol, poly Glycerin, and the like. More preferred are polyvinyl alcohol and polysaccharides. The polysaccharide referred to here is a biopolymer synthesized in a biological system by polycondensation of various monosaccharides, and herein includes those chemically modified based on them. For example, cellulose and cellulose derivatives such as hydroxymethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, amylose,
Amylopectin, pullulan, curdlan, xanthan, chitin, chitosan and the like. For the purpose of improving the water resistance of these resins, a crosslinking agent for a hydrogen bonding group can be used.

The crosslinking agent for the hydrogen bonding group is not particularly restricted but includes, for example, titanium coupling agents, silane coupling agents, melamine crosslinking agents, epoxy crosslinking agents, isocyanate crosslinking agents, copper compounds, zirconia. Compounds, aldehyde compounds and the like are preferable, and zirconia compounds are more preferable.

Specific examples of the zirconia compound include, for example, zirconium halides such as zirconium oxychloride, zirconium hydroxychloride, zirconium tetrachloride and zirconium bromide, zirconium sulfate, basic zirconium sulfate and zirconium mineral acid such as zirconium nitrate. Salt, zirconium formate, zirconium acetate, zirconium propionate, zirconium caprylate, zirconium stearate, and other organic acids, zirconium ammonium carbonate, sodium zirconium sulfate, zirconium ammonium acetate, sodium zirconium oxalate, sodium zirconium citrate, sodium citrate Zirconium complex salts such as zirconium ammonium are exemplified.

The amount of the cross-linking agent for a hydrogen-bonding group is determined by the ratio (K) of the number of moles of the cross-linking group (CN) of the cross-linking agent to the number of moles of the hydrogen-bonding group (HN) of the high hydrogen bonding resin That is, K = C
[N / HN] is preferably in the range of 0.001 or more and 10 or less, more preferably 0.01 or more and 1 or less.

The gas barrier laminate of the present invention is obtained by applying a coating containing a silicic acid condensate and a plate-like pigment to the surface of the support or the molded product and drying the coating. The coating method includes a direct gravure method, a reverse gravure method, a microgravure method, a roll coating method such as a two roll beat coating method, a bottom feed three reverse coating method, and a doctor knife method, a die coating method, and a dip coating method. , Bar coating, kiss coating, lip coating, blade coating, air knife coating, dipping, and brush coating. Further, a method such as a coating method in which these are combined may be used. It is not limited to these methods. The thickness of the dried film of the gas barrier layer is preferably 0.01 μm to 30 μm, more preferably 0.03 μm.
μm to 10 μm, most preferably 0.05 μm to 7 μm
It is. When the thickness of the dried film is less than 0.01 μm, the gas barrier property becomes insufficient, and when the thickness exceeds 30 μm, the gas barrier property not only reaches a plateau, but also the film is easily cracked. Absent.

Examples of the drying method include drying with hot air, drying with dry air, drying with infrared rays, drying with microwaves, drying with a gas burner, and drying with a combination of two or more of these methods. However, the present invention is not limited to this. Further, the paint may be applied twice or more. There is no particular limitation on the drying temperature,
Preferably 50 ° C to 300 ° C, more preferably 70 ° C to
The temperature is 200C, more preferably 90C to 150C.
When a thermoplastic resin is used for the support, it is necessary to dry at a temperature lower than its melting point. Therefore, low-temperature drying is desirable, and the drying temperature is preferably 70 ° C to 120 ° C. Drying temperature is 50
If the temperature is lower than ℃, silicate ion condensation will be insufficient, and water resistance and barrier properties will be insufficient. If it exceeds 300 ° C., the strength of the support deteriorates and the color tone changes, which is not preferable.

[0046]

The present invention will be specifically described below with reference to examples.

Example 1 Montmorillonite (Kunipia F, particle size: 520 nm; manufactured by Kunimine Industries) was ion-exchanged with water (0.7 μs / cm or less) in a lithium silicate solution having a molar ratio of 3.5 (manufactured by Kanto Chemical Co., Ltd.). ) Was mixed at a solid content ratio of 100/20 to prepare a 10% by mass dispersion, which was used as a gas barrier paint containing an alkali metal silicate and a flat pigment. The obtained paint was applied to a polyester film (thickness: 12 μm) with a thickness of 2 μm using a Meyer bar.
μm and 110 ° C using a hot air drier
, And further dried at 130 ° C for 2 minutes to produce a gas barrier laminate.

Example 2 Colloidal silica (Snowtex N; manufactured by Nissan Chemical Industries, Ltd.) was used in place of lithium silicate of Example 1, and the colloidal silica and montmorillonite had a solid content ratio of 10/100 by mass. % Dispersion was prepared in the same manner as in Example 1 except that a gas-barrier coating material was prepared to prepare a gas-barrier coating.

<Comparative Example 1> Gas barrier properties were obtained in exactly the same manner as in Example 1 except that lithium silicate having a molar ratio of 3.0 was used and a 10% by mass dispersion was prepared to obtain a gas barrier paint. Although a laminate was produced, many cracks were generated in the coating film, and the coating film dropped off.

<Comparative Example 2> PVA (PVA107; manufactured by Kuraray Co., Ltd.) was used as a gas barrier paint, and the paint had a thickness of 3
μm polyester film (thickness 12μ)
m) was coated thereon with a Mayer bar and dried in the same manner as in Example 1 to produce a gas barrier laminate. The above Examples and Comparative Examples were evaluated by the following test methods, and the results are shown in Table 1.

<Test Method> 1) Oxygen Permeability Measured under the conditions of 20 ° C. and 80% RH with the coated surface facing the oxygen detector by JIS-K-7126 B method (isobaric method) (oxygen permeability measuring apparatus: OX-TRAN100 type, MOCO
N company). 2) Adhesion of coating film A cellophane tape was applied to the coating surface of the gas barrier laminate, and when the coating film was not peeled off by hand rapidly, it was evaluated as ○, and when peeled, it was evaluated as x.

[0052]

[Table 1]

[0053]

The gas barrier laminate according to the present invention comprises:
It has excellent gas barrier properties, especially excellent gas barrier properties under high humidity conditions and coating strength, and is useful as a material for various packaging.

Claims (13)

[Claims] 1. A gas-barrier laminate having a gas-barrier layer formed on at least one surface of a support, wherein the gas-barrier layer comprises one or more silicate condensates selected from colloidal silica or alkali metal silicates. A gas-barrier laminate comprising a pigment in the form of a gas barrier. 2. The gas barrier laminate according to claim 1, wherein the alkali metal silicate contains lithium silicate. 3. The gas barrier laminate according to claim 1, wherein the tabular pigment has a particle size of 10 nm to 5 μm. 4. The gas barrier laminate according to claim 1, wherein the tabular pigment is an inorganic layer compound. 5. The gas barrier laminate according to claim 4, wherein the inorganic layered compound is a smectite clay. 6. A mass ratio of the silicic acid condensate to the tabular pigment is 9
The ratio is from 5/5 to 5/95.
5. The gas-barrier laminate according to any one of 5. 7. The method according to claim 1, wherein the support is a synthetic resin film.
7. The gas barrier laminate according to any one of items 1 to 6. 8. The gas barrier property according to claim 7, wherein the support is a film mainly composed of at least one resin selected from a polyolefin resin, a polyester resin and a polyamide resin. Laminate. 9. The gas barrier laminate according to claim 7, wherein the support is a polypropylene resin. 10. A support comprising a polyolefin resin layer,
The gas barrier laminate according to claim 7, wherein the laminate is a laminated film formed by laminating one or more resin layers containing a polyamide resin or a polyester resin. 11. The support according to claim 7, wherein the support has a vapor deposition layer, and a gas barrier layer is formed on the vapor deposition layer.
11. The gas barrier laminate according to item 10. 12. The gas barrier laminate according to claim 1, wherein a heat-sealing resin layer is formed on at least one surface. 13. The gas barrier laminate according to claim 1, wherein the support is a molded article formed of a material selected from a synthetic resin, glass, and metal.