JP6776497B2 - Gas barrier resin composition - Google Patents

Description

The present invention relates to a gas barrier resin composition, and more particularly, a gas barrier resin composition containing hexagonal plate-shaped alumina particles having all the following characteristics (a) to (d). Yes, the alumina particles are contained in an amount of more than 40 parts by weight, and the resin contains at least one selected from a water-soluble transparent resin, a water-insoluble transparent resin, and a silane coupling agent, and has a gas barrier property exceeding the conventional level. The present invention relates to a gas barrier resin composition having a gas barrier property, and a method for imparting a gas barrier property. (A) The ratio of the diagonal length to the thickness of the surface with the largest area is 20 or more and 1000 or less, (b) The diagonal length of the surface with the largest area is 100 nm or more and 5000 nm or less, and (c) the thickness is 1 nm or more and 20 nm or less, (d) Alumina particles whose alumina particles are gibsite

In recent years, in the fields of electronics and food packaging, high-performance films having excellent heat resistance and barrier properties have been demanded. In the former case, in addition to the demand for larger size and lighter weight such as electroluminescence (EL) and liquid crystal display element, the demand for flexibility is increasing, and a substrate that replaces the conventionally used glass is being developed. For example, attempts to replace plastic films are being actively made, and it is expected that they will lead to expansion of applications because they are lightweight and have excellent flexibility. Transparency is also a very important property, but it has been difficult to meet all of these requirements with a single resin alone.
Further, in packaging applications, high performance is required not only for food packaging but also for packaging materials for pharmaceuticals and the like for more stable quality.
In response to such a demand, a composite material film in which a filler is contained in a resin is known.

Patent Document 1 discloses a patent relating to a composite film having a fibrous filler made of a cellulose material contained in a resin film and having high dimensional stability and gas barrier properties. However, fibrous fillers made of cellulosic materials need to be co-existing with preservatives in order to be preserved to prevent spoilage, which has an effect when forming industrially usable compositions. May be given, and there is still room for improvement.

In Patent Document 2, an inorganic thin film is formed on a base film by vapor deposition, and defects are coated with a dispersion liquid composed of polymer silica particles due to physical factors such as foreign matter contamination, bending and rubbing in the vapor deposition process. A technique for improving gas barrier properties by closing the pinholes of a thin film is described. However, in this method, it is necessary to separately coat with polymer silica particles in order to make up for the defect of the formed vapor-film film, and there is still room for improvement in order to easily impart gas barrier properties.
The mechanism by which the gas barrier property is exhibited is that the added filler particles act as a barrier when the gas molecules permeate the film, so that the gas molecules have to sew through the gaps between the filler particles and permeate. The filler particle shapes used in the prior arts 1 and 2 are fibrous and spherical, respectively, and there is still room for improvement as a filler agent that imparts gas barrier properties.

Patent Document 3 discloses a barrier film using a swellable inorganic layered compound, for example, a clay mineral. However, clay particles have a problem of swelling and causing cracks and cracks under high humidity, and it is necessary to solve these problems in applications requiring high dimensional accuracy and stability.

JP 2006-2829223 Japanese Patent Application Laid-Open No. 2008-36863 JP-A-2002-293984

Provided is a gas barrier resin composition containing an inorganic oxide that has never existed before.

The means for solving the above problems is
(1) A gas barrier resin composition containing alumina particles having a hexagonal plate shape that satisfies all of the following (a) to (d).
(A) The ratio of the diagonal length to the thickness of the surface having the largest area of the alumina particles is 20 or more and 1000 or less (b) The diagonal length of the surface having the largest area of the alumina particles is 100 nm or more and 5000 nm or less (c) ) Alumina particle thickness is 1 nm or more and 20 nm or less (d) Alumina particle crystal is gibsite (2) The gas barrier resin composition according to (1) contains alumina particles in an amount of more than 40 parts by weight and 99 parts by weight or less. A composition characterized by.
(3) The gas barrier resin composition according to (1), wherein the resin contains at least one selected from a water-soluble transparent resin, a water-insoluble transparent resin, and a silane coupling agent.
(4) A method for imparting gas barrier properties, which comprises using a resin composition containing alumina particles having a hexagonal plate shape that satisfies all of the following (a) to (d).
(A) The ratio of the diagonal length to the thickness of the surface having the largest area of the alumina particles is 20 or more and 1000 or less (b) The diagonal length of the surface having the largest area of the alumina particles is 100 nm or more and 5000 nm or less (c) ) Alumina particle thickness is 1 nm or more and 20 nm or less (d) Alumina particle crystals are gibsite

In the gas barrier property resin composition, a resin composition containing alumina particles having a hexagonal plate shape satisfying all of the following (a) to (d) can exhibit a special gas barrier property.
(A) The ratio of the diagonal length to the thickness of the surface with the largest area is 20 or more and 1000 or less (b) The diagonal length of the surface with the largest area is 100 nm or more and 5000 nm or less (c) The thickness is 1 nm or more 20 nm or less (d) Alumina particles crystal is gibbsite When the alumina particles having the above-mentioned characteristics are contained in an amount of more than 40 parts by weight and 99 parts by weight or less, it is possible to impart unprecedented high gas barrier properties. When the resin contains at least one selected from a water-soluble transparent resin, a water-insoluble transparent resin, and a silane coupling agent, it is transparent, has excellent followability with the substrate resin, and easily imparts gas barrier properties. be able to. By using a resin composition containing alumina particles having a hexagonal plate shape that satisfies all of the following (a) to (d), it is possible to provide a method for imparting a high gas barrier property that has never been seen before.
(A) The ratio of the diagonal length to the thickness of the surface with the largest area is 20 or more and 1000 or less (b) The diagonal length of the surface with the largest area is 100 nm or more and 5000 nm or less (c) The thickness is 1 nm or more Crystals of (d) alumina particles of 20 nm or less give Gibbsite The present invention relates to a resin composition in which alumina particles having a specific shape are added to a resin at a high filling rate, and exhibits an unprecedented excellent gas barrier property. It can contribute widely to the development of industry. Specifically, it can be expected to be developed as a gas barrier film that requires transparency, such as food packaging films, pharmaceutical packaging films, and display members.

FIG. 1 is a TEM photograph of the hexagonal plate-shaped alumina particles used in Example 1.

Most of the crystals (about 80% or more) of the hexagonal plate-shaped alumina particles constituting the present invention have a substantially hexagonal plate-like shape as primary particles, and in the dispersion liquid, the alumina particles are A part of the primary particles can be aggregated to form secondary particles within the range where the dispersed state can be maintained, and the average diagonal length (also called the long side) and the average of the surface having the largest area. The thickness (also referred to as the short side) ratio (also referred to as the aspect ratio) is 20 to 1000, and the preferred average aspect ratio is 30 to 900. When the average aspect ratio of the alumina particles is less than 20, the orientation of the particles is low due to self-organization, and a dense structure expressing high barrier properties cannot be obtained. When the average aspect ratio of the particles exceeds 1000, the particles are transparent. It is not preferable because it does not have an aspect ratio and cracks are likely to occur in the film and the composition is not dense. Further, since the alumina particles having a shape having no anisotropy do not have orientation, cracks are likely to occur in the composition and the composition does not become a dense composition having high strength, and a composition having a high barrier property can be obtained. Not preferable because it does not exist. Having anisotropy in the present invention means that the average diagonal length and thickness of the surface having the largest area of the particle are different, and the spherical shape having no side or the length of all the sides. Shapes such as regular triangular pyramids and squares with the same equality are not included. Further, having orientation in the present invention means a state in which most of the anisotropic particles are arranged with a specific surface equal to that on the base material in a certain direction, and the orientation of the particles is It does not include the state of being irregularly arranged on the substrate. Having anisotropy or orientation means that the surface or composition of the gas barrier composition is 30,000 times or more using a known scanning electron microscope (also referred to as SEM) or a transmission electron microscope (also referred to as TEM). It can be confirmed by magnifying the dispersion liquid used for forming the above and observing the alumina particles.

The thickness of the hexagonal plate-shaped alumina particles constituting the present invention is 1 to 20 nm, preferably 3 to 15 nm as the primary particles. If it is less than 1 nm, the dispersibility in the sol state in which the alumina particles are dispersed in the medium is low and it becomes difficult to form a uniform composition, which is not preferable. If it exceeds 20 nm, the transparency is lowered when compounded with the resin. However, it may be a problem in applications that require high transparency, which is not preferable. The average diagonal length of the surface having the largest area of the alumina particles constituting the present invention is 100 to 5000 nm, preferably 200 to 3000 nm as the primary particles. If it is less than 100 nm, it may not show sufficient gas barrier property, which is not preferable, and if it exceeds 5000 nm, the transparency is lowered, which may cause a problem in applications requiring high transparency, which is not preferable. The fact that the particles have the above-mentioned shape and size can also be confirmed by observing the particles at a magnification of 30,000 times or more using SEM or TEM.

The gas barrier resin composition constituting the present invention exhibits remarkable gas barrier properties by containing more than 40 parts by weight of alumina particles and 99 parts by weight or less of more than 40 parts by weight as the weight excluding the dispersion medium. be able to. If the content of alumina is 40 parts by weight or less or more than 99 parts by weight, sufficient gas barrier properties may not be exhibited, which is not preferable.

The crystal system of the alumina particles constituting the present invention has a main crystal form of gibbsite, and can include other crystal forms as long as it does not affect the gas barrier property. The main crystal form referred to in the present application means that 80% or more of the crystals constituting alumina are gibbsite, and the fact that the main crystal form is gibbsite forms the surface or composition of the gas barrier composition. It can be confirmed by comparing the peak intensity ratios obtained by X-ray diffraction of the dispersion liquid used for the crystallization. When the main crystal is another crystal system, it is not preferable to obtain a crystal having a shape characterized by the present application because it requires harsh reaction conditions and is difficult to provide easily.

Next, the method for producing the heat-resistant coating of the present invention will be described. A known method can be applied to the method for producing an alumina crystal used in the gas barrier resin composition of the present invention (for example, Japan Society of Color Material Vol. 50, No. 9, P500-504, etc.), and is particularly specified. Although not a typical example, the following method can be mentioned.

Hexagonal plate-shaped alumina hydrate particles having a thickness of 1 to 20 nm, an average diagonal length of the surface having the largest area of 100 to 5000 nm, and an aspect ratio of 20 to 1000 are dispersed. A method of mixing an aqueous alumina sol with a resin to prepare a dispersion liquid and applying it to a base material to remove an excess dispersion liquid and removing a dispersion medium will be described.

The aqueous alumina sol can be produced by hydrolyzing and degluing a hydrolyzable aluminum compound under acidic conditions to which an organic acid or an inorganic acid is added. By appropriately selecting the type of hydrolyzable aluminum compound and the conditions for hydrolysis and gelatinization by a known method, it is possible to produce an aqueous alumina sol composed of alumina hydrate particles which are gibbsite having a specific shape. it can.

As the hydrolyzable aluminum compound, an aluminum compound having various organic groups can be used. Examples of the aluminum compound having an organic group include aluminum alkoxides such as ammonium carbonate and aluminum acetate, aluminum ethoxydos, aluminum isopropoxides, aluminum n-butoxides, aluminum sec-butoxides and the like, and cyclic aluminum oligomers. , Aluminum chelate such as diisopropoxy (ethylacetacetate) aluminum, tris (ethylacetacetate) aluminum, organic aluminum compound such as alkylaluminum, and the like are exemplified.
Among these compounds, aluminum alkoxides are preferable, and those having an alkoxyl group having 2 to 5 carbon atoms are particularly preferable because they have appropriate hydrolyzability and can easily remove by-products. The amount of water required for hydrolysis is not particularly limited, but at least 3 mol is required for 1 mol of aluminum atoms, and this may be added at once or in stages. If the amount of water added is less than 3 mol, the hydrolysis reaction is not completed and it is difficult to obtain alumina particles having a certain shape, which is not preferable.

The acidic conditions are not particularly limited, but are generally pH 1 to 6, and a range of pH 1 to 4 is particularly preferable, but alkaline conditions are not preferable because thick crystals are formed. Examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid and the like, and examples of the organic acid include alkylcarboxylic acids typified by formic acid and acetic acid, methanesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, dodecylsulfonic acid and dodecylbenzene. Sulfonic acids such as sulfonic acid can be used, and the inorganic acid is preferably nitrate which does not erode stainless steel, and the organic acid is preferably formic acid or acetic acid which is inexpensive and easily available. The thawing temperature can be selected from the range of -10 to 130 ° C., the reaction time can be selected from 0.5 to 48 hours, and the desired aging time after the reaction is completed. It can be selected in a timely manner according to the situation. When the reaction temperature exceeds 130 ° C., gibbsite decreases and the proportion of γ-alumina increases, and when the reaction temperature is lower than -10 ° C., the reaction may not be completed in an industrially available time, which is not preferable. If the reaction time is less than 0.5 hours, the reaction may not be completed, and a reaction time of more than 48 hours is not suitable for industrial mass production, which is not preferable. If the reaction time is extended or the aging time after the reaction is completed, the aspect ratio of the crystals is increased, and if the reaction time is shortened or the aging time is shortened, crystals with a small aspect ratio are obtained, and these should be adjusted in a timely manner. A crystal of a desired size can be obtained.

The concentration of the reaction is preferably adjusted so that the gibbsite particles in the aqueous alumina sol are 0.1 to 30 parts by weight, more preferably 0.5 to 20 parts by weight.
When the concentration of alumina particles in the aqueous alumina sol is 0.1 part by weight or less, it is necessary to repeat the coating-drying operation in order to obtain an appropriate film thickness, which is not preferable because the operation becomes complicated and 30 weight by weight. In the case of more than one part, the viscosity of the dispersion liquid is high and it is difficult to mix with the resin, and not only is it difficult to obtain a film with a uniform thickness, but also the stress after removing the dispersion medium by forming a thick film at one time. Is not preferable because the amount of particles increases, cracks occur, and the film peels off.

In the production of the gas barrier resin composition of the present invention, the pH of the hexagonal plate-shaped alumina dispersion used is preferably 2 to 9 because a stable dispersion can be formed, and a pH adjusting reagent is preferable. As, organic amines such as sodium hydroxide, potassium hydroxide, sodium carbonate, sodium hydrogen carbonate, ammonia, alkylamines, alkanolamines, tetramethylammonium hydroxides, ureas, and aromatic amines can be used.
Inorganic hydroxides, carbonates, and the like may impair transparency when the dispersion medium is removed. Therefore, it is preferable to use organic amines in order to use them in undesired applications. Furthermore, if the substrate to be coated and / or the coating operation is not affected by pH, the addition of this type of regulator is not particularly required and the pH adjusting additive is not particularly limited and is particularly limited. It is not something that is done.
In addition to the pH adjustment described above, it is also possible to perform deionization treatment using an ion exchange resin, RO membrane, or the like to adjust the pH.

The alumina particles according to the present invention can be used in a state of being dispersed in the water used at the time of production, but it is difficult to mix with the resin or apply to the base material because the dispersion medium of the metal oxide is water. In this case, in addition to improving the coatability by adding a monovalent alcohol having 1 to 3 carbon atoms or a water-soluble organic solvent such as DMF, ethyl acid phosphate, butyl acid phosphate, butyl pyrophosphate, butoxyethyl acid phosphate, etc. 2-Ethylhexyl acid phosphate, oleyl acid phosphate, tetracosyl acid phosphate, phenyl acid phosphate, diphenyl acid phosphate, benzyl acid phosphate, n-octyl acid phosphate, (2-hydroxyethyl) methacrylate acid phosphate, dibutyl phosphate, bis (2) -Ethylhexyl) phosphate, lauryl acid phosphate, stearyl acid phosphate, ethylene glycol monoethyl ether acid phosphate, triethylene glycol monoethyl ether acid phosphate, phosphorus compounds such as triethylene glycol monobutyl ether acid phosphate, methanesulfonic acid, ethanesulfon Alkyl sulfonic acids such as acids, benzene sulfonic acids, p-toluene sulfonic acids, styrene sulfonic acids, aromatic sulfonic acids such as alkyl benzene sulfonic acids, and esters with these lower alcohols, alkali metal salts, ammonium salts and the like Alumina by a known method using an acid, a polyhydric alcohol, a carboxylic acid compound, a surfactant, etc. so as to disperse in a water-insoluble organic solvent such as toluene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, acetic acid ester, etc. It can also be used as an organosol by modifying the surface of.

When the dispersion medium is water, the alumina particle dispersion liquid can form a film by mixing one or more of less than 40 parts by weight of the resin with respect to the alumina particles, and the resin to be mixed. There is no problem whether the polymerized resin is mixed or the monomer is mixed and then polymerized. As the water-soluble resin, polyvinyl alcohol, polyvinyl acetate, polyvinylpyrrolidone, polyacrylic acids, polyethyleneimine, polyimide and the like can be used, and polyvinyl alcohol is particularly preferable. Further, the synthetic resin constituting the gas barrier resin composition of the present invention is known as 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyl. Trimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxy A silane coupling agent such as silane, 3-methacryloxypropylmethyldiethoxysilane, or 3-methacryloxypropyltriethoxysilane can be used. When the dispersion medium is an organosol which is an organic solvent, polycarbonate and acrylic resin can be used in the same manner. If the amount of the resin composition exceeds 40 parts by weight or less than 1 part by weight with respect to alumina, the gas barrier property is lowered, which is not preferable.

The alumina resin composition liquid can be applied to various general base materials, and the base material is a curable resin such as a thermosetting resin or a high-energy ray-curable resin, or a thermoplastic. The resin is a resin in which the curable resin precursor is cross-linked and cured by heat, and the high-energy ray-curable resin is a resin that is cross-linked and cured by high-energy rays such as ultraviolet rays and electron beams. A plastic resin is a resin that softens and melts when heated, and includes epoxy resin, thermosetting polyimide, phenol resin, amino resin such as melamine resin and urea resin, unsaturated polyester, and polyurethane, and high energy ray curing. Examples of the sex resin include acrylic resins and epoxy resins obtained by utilizing photocationic polymerization, and examples of the thermoplastic resin include polyethylene, polypropylene, ethylene oxide-propylene oxide copolymer, polyvinyl chloride, polyvinyl acetate, and the like. Saturated polyesters such as polyethylene glycol, polyethylene oxide, polyvinyl alcohol (including partially saponified products), polyvinyl acetal (including partially acetal products), polyvinylpyrrolidone, polytetrafluoroethylene, acrylic resin, polyethylene terephthalate, polyamide, polycarbonate, polyamideimide , Thermoplastic polyimide, polyether sulfone and the like can be used. As the base material other than the resin, a ceramic member such as glass can be selected.

Examples of the coating method on the base material include a method of uniformly coating the support with an alumina dispersion dispersed in water, a method of coating on the surface by a roll coat or the like, or a uniformly dispersed alumina-resin. Examples thereof include a dip method in which the base material is immersed in the dispersion for a certain period of time, then pulled up at a constant speed to remove excess alumina dispersion, and then dried.

As a method for removing the dispersion medium after applying the dispersion liquid to the base material, a known evaporation method is preferable, and the resin used from room temperature or the desired temperature range below the heat resistance limit of the base material, whichever is lower. The temperature suitable for the working environment can be selected, and the gas barrier resin composition of the present invention can be obtained by drying for about 1 minute to 24 hours according to the evaporation time of the dispersion medium.

The thickness of the film when coating the gas barrier resin composition of the present invention can be easily adjusted by the concentration of alumina particles in the dispersion medium and the liquid film thickness at the time of coating. When the concentration of the alumina particles is low, a thin film is formed, and when the concentration is high, a thick film is formed, and the desired film thickness can be obtained by adjusting the concentration. The thickness of the film obtained by one application is not particularly limited, but in general, a film in the range of 0.01 to 100 μm can be produced, and the coating operation is repeated as necessary to obtain the desired thickness. It can also be a film. The thickness of the coating film is not limited, but generally 0.05 to 50 μm is preferable because a transparent coating film having sufficient gas barrier properties can be formed. The thickness of the coating film formed on the base material is measured by measuring the increased thickness of the coating material with respect to the base material using a known high-precision micrometer (for example, high-precision digital micrometer MDH-25M manufactured by Mitutoyo Co., Ltd.) or the like. Alternatively, it can be confirmed by observing the cross section at a magnification of about 10,000 times using a known scanning electron microscope (also referred to as SEM).

It can be confirmed that the present invention exhibits gas barrier properties by comparing the oxygen permeation rate of the gas barrier film in which the gas barrier resin composition is formed on the resin film and the resin film as the base material. The gas barrier property as used in the present invention refers to a resin composition having a gas barrier property that reduces the gas permeation rate by 30% or more as compared with the oxygen permeation rate of the base material alone. When the decrease in oxygen permeation rate is less than 30%, no significant difference may be seen when it is put into practical use, which is not preferable.

Next, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

(Example 1)
Hexagonal plate-shaped gibsite sol with an average degree of polymerization of 1,000 and a 10 wt% aqueous solution of completely saponified polyvinyl alcohol (PVA): 10 g and a solid content of 10 wt% (average thickness: 5 nm, average of the plane with the largest area) Diagonal length: 200 nm, aspect ratio 40) 90 g was mixed, stirred for 10 minutes, and then bubbles were removed under reduced pressure to prepare a milky white mixed dispersion. This mixed dispersion was applied onto a PET film having a thickness of 12 μm (oxygen permeation rate: 130 cc / m ² , day, atm) using a wire bar with a liquid thickness of 6 μm. A hexagonal plate-PVA transparent composite film was prepared on a PET film by drying at room temperature for 2 hours and at 50 ° C. for 30 minutes. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 43 cc / m ² · day · atm.

(Example 2)
A mixture of 40 g of a 10 wt% polyvinyl alcohol aqueous solution and 60 g of a hexagonal plate-shaped gibsite sol (average thickness: 5 nm, average diagonal length of the largest plane: 200 nm, aspect ratio 20) with a solid content of 10 wt%. A transparent hexagonal plate-silica composite film was prepared on the PET film by the same operation as in Example 1 except that the above was used. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 63 cc / m ² · day · atm.

(Example 3)
The procedure was the same as in Example 1 except that a 10 wt% 3-glycidoxypropyltrimethoxysilane (KBM403 manufactured by Shin-Etsu Polymer Co., Ltd.) methanol solution was used instead of polyvinyl alcohol, and a transparent hexagonal plate was formed on the PET film. -A silica composite film was prepared. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 86 cc / m ² · day · atm.

(Example 4)
1.0 g of 10 wt% polyvinyl alcohol aqueous solution and 99 g of hexagonal plate-shaped gibsite sol (average thickness: 5 nm, average diagonal length of the largest plane: 200 nm, aspect ratio 40) with a solid content of 10 wt%. A transparent hexagonal plate-PVA composite film was prepared on the PET film by the same operation as in Example 1 except that the mixed solution was used. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 82 cc / m ² · day · atm.

(Comparative Example 1)
The same procedure as in Example 1 was carried out except that the mixing ratio of polyvinyl alcohol was changed to 90 g and 10 g of hexagonal plate-shaped gibbsite sol to prepare a transparent hexagonal plate-PVA composite film on the PET film. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 131 cc / m ² · day · atm.

(Comparative Example 2)
A transparent boehmite-PVA composite film was prepared on a PET film by the same operation as in Example 1 except that the hexagonal plate-shaped gibbsite sol was changed to a 10 wt% boehmite sol having a primary particle size of 20 nm × 20 nm. did. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 132 cc / m ² · day · atm.

(Comparative Example 3)
The PET film was operated in the same manner as in Example 1 except that the hexagonal plate-shaped gibsite sol (average thickness: 5 nm, average diagonal length of the plane having the largest area: 200 nm) was used without using polyvinyl alcohol. A hexagonal plate-shaped gibsite film was prepared on the top. The film thickness of this film was 0.5 μm, and as a result of measuring the oxygen permeation rate, it was 98 cc / m ² · day · atm.

Comparing the results of Example 1 with the results of Comparative Example 1, when the amount of alumina added was reduced, no difference was observed from the oxygen permeation rate of the PET film as a base material alone, and no gas barrier property was exhibited. Comparing the results of Example 1 and the results of Comparative Example 2, when alumina particles having no specific shape were used, no difference was observed from the oxygen permeation rate of the PET film as a base material alone, and no gas barrier property was exhibited. It was. Similarly, when the results of Example 4 and the results of Comparative Example 3 were compared, when alumina alone containing no resin was used, the gas barrier property was improved but a sufficient value was not shown, but the resin was 1 wt. The addition of% showed a remarkable gas barrier effect.
From the above results, it was confirmed that the composition obtained by mixing alumina, which is a gibbsite having a specific shape, with a resin containing more than 40 parts by weight and 99 parts by weight or less, exhibits a transparent and remarkably gas barrier property. ..

Claims (5)

The gas barrier property of the gas barrier resin composition, which contains alumina particles having a hexagonal plate shape and a completely saponified polyvinyl alcohol satisfying all of the following (a) to (d) and excluding the dispersion medium. In 100 parts by weight of the resin composition, the content of the alumina particles exceeds 40 parts by weight and is 99 parts by weight or less, and the content of the completely saponified polyvinyl alcohol is 1 part by weight or more and 40 parts by weight or less. Stuff.
(A) The ratio of the diagonal length to the thickness of the surface having the largest area of the alumina particles is 20 or more and 1000 or less (b) The diagonal length of the surface having the largest area of the alumina particles is 100 nm or more and 5000 nm or less (c) ) Alumina particle thickness is 1 nm or more and 20 nm or less (d) Alumina particle crystals are gibsite The gas barrier resin composition according to claim 1, wherein the content of the alumina particles is 60 parts by weight or more and 99 parts by weight or less. The gas barrier resin composition according to claim 1 or 2, which is a coating film having a thickness of 0.05 μm or more and 50 μm or less. A gas-barrier resin composition containing alumina particles having a hexagonal plate shape and a completely saponified polyvinyl alcohol that satisfy all of the following (a) to (d), and the gas-barrier resin excluding the dispersion medium. Gas barrier property in which the content of the alumina particles exceeds 40 parts by weight and is 99 parts by weight or less in 100 parts by weight of the composition, and the content of the completely saponified polyvinyl alcohol is 1 part by weight or more and 40 parts by weight or less . A method for imparting gas barrier properties, which comprises using a resin composition .
(A) The ratio of the diagonal length to the thickness of the surface having the largest area of the alumina particles is 20 or more and 1000 or less (b) The diagonal length of the surface having the largest area of the alumina particles is 100 nm or more and 5000 nm or less (c) ) Alumina particle thickness is 1 nm or more and 20 nm or less (d) Alumina particle crystals are gibsite The method for imparting gas barrier properties according to claim 4, wherein a dispersion liquid in which the gas barrier resin composition is dispersed in a dispersion medium is applied and dried on a substrate to form a film having a thickness of 0.05 μm or more and 50 μm or less. ..