JP5270084B2 - Moisture-proof composition and moisture-proof sheet using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a moistureproof composition excellent in water vapor-barrier property, and to provide a moistureproof sheet using the same. <P>SOLUTION: The moistureproof composition comprises a reaction product of a water-soluble polymer and a tetraalkoxysilane hydrolyzate 5% or greater in the ratio of the number of nonsubstituted silicon atoms plus monosubstituted silicon atoms to the total number of nonsubstituted silicon atoms and mono- to trisubstituted silicon atoms: [(the number of nonsubstituted silicon atoms + the number of monosubstituted silicon atoms)/(the number of nonsubstituted silicon atoms + the number of mono- to trisubstituted silicon atoms)]&times;100(%). The moistureproof sheet using the above composition is also provided. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to a moisture-proof composition having excellent water vapor barrier properties and a moisture-proof sheet using the same.

In barrier packaging films for foods, electronic parts and medical parts, base films such as polyethylene terephthalate films, nylon films, polypropylene films and the like for the purpose of imparting functions such as gas barrier properties (oxygen barrier properties, water vapor barrier properties, etc.) A gas barrier composition (oxygen barrier composition, moisture-proof composition, etc.) or the like is applied to the surface.
For example, Patent Document 1 discloses a gas barrier composition such as a mixture of a partially hydrolyzed polycondensate of alkoxide and a water-soluble polymer or a reaction product of the partially hydrolyzed polycondensate and water-soluble polymer. The present invention proposes a laminated film in which a polymer gas barrier layer made of the gas barrier composition is disposed between two layers made of polyolefin resin.
Patent Document 2 discloses that a polyvinyl alcohol resin, silicon alkoxide, lower alcohol, water, and a silicon alkoxide hydrolysis catalyst have a polyvinyl alcohol resin / silicon alkoxide weight part ratio of 100/300 to 100/600. A gas barrier film is proposed in which a silicon alkoxide is hydrolyzed and then coated on a thermoplastic resin film with a coating liquid from which the silicon alkoxide hydrolysis catalyst has been removed.
Further, Patent Document 3 discloses that a composite polymer layer obtained by polycondensation of a coating composition containing alkoxysilane or a hydrolyzate thereof and polyvinyl alcohol and / or ethylene-vinyl alcohol copolymer is used as a thermoplastic resin substrate. A barrier laminate film laminated on at least one side of the film is proposed.
However, all of these inventions use alkoxysilane or a polycondensate of a hydrolyzate thereof as a gas barrier composition, particularly an oxygen barrier composition, and are satisfactory in terms of performance as a moisture-proof composition. It wasn't.

JP 2000-343659 A JP 2002-60525 A JP 2006-82239 A

  Under such circumstances, an object of the present invention is to provide a moisture-proof composition excellent in water vapor barrier properties and a moisture-proof sheet using the same.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that a composition containing a reaction product of a specific tetraalkoxysilane hydrolyzate and a water-soluble polymer exhibits remarkable moisture resistance. I found it. The present invention has been completed based on such findings.
That is, the gist of the present invention is as follows.
(1) Quantity ratio of unsubstituted silicon and 1-substituted silicon to the total number of unsubstituted silicon and 1 to 3 substituted silicon {(number of unsubstituted silicon + 1 number of substituted silicon) / (number of unsubstituted silicon + 1 to 3 substituted silicon)} A moisture-proof composition containing a reaction product of a tetraalkoxysilane hydrolyzate and a water-soluble polymer, wherein x100 (%) is 5% or more,
(2) The moisture-proof composition according to (1), wherein the tetraalkoxysilane is a silane selected from at least one silane represented by the following general formula (I).

上記一般式（Ｉ）中、Ｒ¹、Ｒ²、Ｒ³及びＲ⁴はそれぞれ炭素数１〜４のアルキル基であり、同じであっても異なっていてもよい。

In the general formula (I), R ¹ , R ² , R ³ and R ⁴ are each an alkyl group having 1 to 4 carbon atoms and may be the same or different.

(3) The moisture-proof composition according to (1) or (2), wherein the water-soluble polymer is polyvinyl alcohol and / or polyethylene vinyl alcohol,
(4) A moisture-proof sheet obtained by laminating the moisture-proof composition according to any one of (1) to (3) above on a base film,
(5) The moisture-proof sheet of the above (4), wherein the substrate film is made of a polyester resin and / or a polyamide resin, and (6) a metal thin film layer and a gap between the moisture-proof composition layer and the substrate film (4) The moisture-proof sheet according to (4) or (5), which is formed by laminating an inorganic compound thin film layer.

  ADVANTAGE OF THE INVENTION According to this invention, the moisture-proof composition excellent in water vapor | steam barrier property and a moisture-proof sheet using the same can be provided.

The moisture-proof composition of the present invention is a ratio of the number of unsubstituted silicon and 1-substituted silicon to the total number of unsubstituted silicon and 1 to 3 substituted silicon {(number of unsubstituted silicon + 1 number of substituted silicon) / (number of unsubstituted silicon + 1 to 1 The number of 3-substituted silicon)} × 100 (%) includes a reaction product of a tetraalkoxysilane hydrolyzate and a water-soluble polymer that is 5% or more. If it is less than 5%, the water vapor barrier property of the present invention cannot be enjoyed.
Here, unsubstituted silicon refers to silicon bonded to four hydroxyl groups, and monosubstituted silicon refers to silicon bonded to three hydroxyl groups and one siloxane group (—O—Si). Silicon refers to silicon bonded to two hydroxyl groups and two siloxane groups (—O—Si). Tri-substituted silicon refers to silicon bonded to one hydroxyl group and three siloxane groups (—O—Si).

  The tetraalkoxysilane used in the moisture-proof composition of the present invention is preferably a silane selected from at least one silane represented by the general formula (I). Examples of these tetraalkoxysilanes include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, tetrabutoxysilane, and dimethoxydiethoxysilane.

The tetraalkoxysilane is mixed with water and alcohol, and a hydrolysis catalyst is added to the mixed solution to cause hydrolysis. The obtained tetraalkoxysilane hydrolyzate is mixed and reacted with the water-soluble polymer, and the reaction product becomes a moisture-proof component of the moisture-proof composition.
Here, examples of the alcohol include isopropyl alcohol, n-propyl alcohol, ethanol, methanol and the like.
Hydrolysis catalysts include inorganic acids such as hydrochloric acid, nitric acid, sulfuric acid and phosphoric acid, organic phosphoric acid, formic acid, acetic acid, acetic anhydride, chloroacetic acid, propionic acid, butyric acid, valeric acid, citric acid, gluconic acid, succinic acid. Examples include acids, tartaric acid, lactic acid, fumaric acid, malic acid, itaconic acid, oxalic acid, mucous acid, uric acid, barbituric acid, and p-toluenesulfonic acid, and acidic catalysts such as acidic cation exchange resins.

In order to make the quantity ratio of unsubstituted silicon and 1-substituted silicon to 5% or more with respect to the total number of unsubstituted silicon and 1 to 3 substituted silicon of the above-mentioned tetraalkoxysilane hydrolyzate, dehydration condensation reaction after hydrolysis reaction is performed. It is desirable to take measures such as (1) shortening the reaction time, (2) lowering the reaction temperature, and (3) reducing the amount of hydrolysis catalyst so as not to proceed too much. As the dehydration condensation reaction proceeds, the generated silanol groups (—Si—OH) condense, increasing the siloxane bonds (Si—O—Si), reducing the reactivity of the tetraalkoxysilane hydrolyzate, and providing a water vapor barrier property. This is because of a decrease.
(1) to (3) preferably combine a plurality of measures as appropriate.

The water-soluble polymer used in the moisture-proof composition of the present invention is preferably polyvinyl alcohol and / or polyethylene vinyl alcohol.
The polyvinyl alcohol preferably has a saponification degree of 75 mol% or more, and the polyethylene vinyl alcohol preferably has 60 mol% or more of vinyl alcohol units.
The polyvinyl alcohol or polyethylene vinyl alcohol may be modified with a silyl group, an acetoacetyl group, or the like within a range not impairing the effects of the present invention. The degree of polymerization of the polyvinyl alcohol or polyethylene vinyl alcohol is preferably from 100 to 5,000, more preferably from 300 to 3,000, considering water vapor barrier properties and processability.

The moisture-proof composition of the present invention can further contain a silane coupling agent.
A known organic reactive group-containing organoalkoxysilane can be used as the silane coupling agent.
In the present invention, an organoalkoxysilane having an epoxy group is particularly suitable, for example, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxy). (Cyclohexyl) ethyltrimethoxysilane and the like.
The above silane coupling agents may be used alone or in combination of two or more.
In this invention, the usage-amount of the above silane coupling agents can be used within the range of 1-20 weight part with respect to 100 weight part of said tetraalkoxysilane hydrolysates.

The moisture-proof composition of the present invention is applied to a substrate film and dried to form a coating film, whereby a moisture-proof sheet is obtained.
Although it does not specifically limit as a base film, Polyester resin, such as polyethylene terephthalate (henceforth PET), polybutylene terephthalate, polyethylene terephthalate, Polyamide resin, such as nylon 6, nylon 6, 6, Polyolefin, such as polypropylene and polyethylene A resin or the like, or a mixture obtained by melting and mixing two or more of these is preferable. Of these, polyester resins and / or polyamide resins are preferable because of their high mechanical strength. Among them, polyester resins are more preferable because they have sufficient heat resistance and mechanical strength, and PET is particularly preferable. The substrate film may be an unstretched film or a uniaxial or biaxially stretched film. Moreover, you may use what laminated | stacked two or more base film.
The drying conditions after coating are not particularly limited as long as they do not cause deformation of the base film, but are preferably 100 to 200 ° C. for 30 seconds to 10 minutes.

If desired, a metal thin film layer and / or an inorganic compound thin film layer may be laminated between the moisture-proof composition layer of the present invention and the substrate film.
The metal thin film layer is preferably formed by depositing a metal such as aluminum on a base film by a PVD method (physical vapor deposition method) (vacuum vapor deposition method, ion plating method, sputtering method, etc.).
Also, the inorganic compound thin film layer is made of PVD method (physical vapor deposition method) (vacuum vapor deposition method, ion plating method, sputtering method, etc.) on a base film with a metal oxide such as silica, zirconia (zirconium dioxide), alumina, etc. The thin film layer is preferably formed by a sol-gel method, an LPD method (liquid phase deposition method), or the like.
Here, the sol-gel method is a method in which alkoxysilane and other metal alkoxides are hydrolyzed and polycondensed, and the obtained coating solution is applied to a substrate film or a molded body. The LPD method is a boric acid (fluoride ion scavenger) that easily reacts with fluoride ions in a hydrolysis equilibrium reaction system (ligand substitution reaction) of a metal fluoro complex in an aqueous solution to form a more stable compound. ) To form a more stable complex ion with free fluoride ions in the system, shift the equilibrium reaction system to the oxide deposition side, and form an oxide thin film on the substrate immersed in the reaction aqueous solution. It is the method of making it precipitate.
The thickness of the metal thin film layer and / or the inorganic compound thin film layer is preferably 0.001 to 10 μm, and particularly preferably 0.01 to 1 μm. Further, by laminating a plurality of metal thin film layers and / or inorganic compound thin film layers, it is possible to further improve gas barrier properties.

Examples The present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
The ²⁹ Si-NMR measurement and the water vapor transmission rate were evaluated according to the following methods.
(1) ²⁹ Si-NMR measurement In a quartz NMR sample tube, tetraalkoxysilane hydrolyzate / acetone-D6 NMR / TMS mixed solution (tetraalkoxysilane hydrolyzate / acetone-D6 NMR / TMS = 60% by mass / 35 (Mass% / 5 mass%) 0.5 g was added, and the ²⁹ Si-NMR spectrum was measured using a nuclear magnetic resonance apparatus (manufactured by JEOL, FT NMR, JNM-AL400) at room temperature and 1200 times of integration. .
When tetramethylsilane (TMS) is used as a reference substance and the total peak area in the −70 ppm to −106 ppm region is 100, the peak area ratio in the −70 ppm to −80 ppm region indicates the quantity ratio of unsubstituted silicon, and from −81 ppm The peak area ratio in the −87 ppm region indicates the quantity ratio of 1-substituted silicon, the peak area ratio in the −88 ppm to −96 ppm area indicates the quantity ratio of the 2-substituted silicon, and the peak area ratio in the −97 ppm to −106 ppm region is 3 substitutions. The quantity ratio of silicon is shown.
(2) Measurement of water vapor transmission rate The water vapor barrier property of the resulting moisture-proof sheet was measured using a water vapor transmission rate measuring device (MOCON PERMATRAN-W3 / 33, manufactured by MOCON) at a temperature of 40 ° C, humidity of 100%, and carrier gas. The measurement was performed under the conditions of a flow rate (nitrogen gas) of 20 cm ³ / min and a measurement time of 4.5 hours.

Example 1
In a four-necked flask equipped with a reflux condenser and a stirrer, a water / isopropyl alcohol / tetraethoxysilane mixed solution (water / isopropyl alcohol / tetraethoxysilane = 38.6 mass% / 52.4 mass% / 9.0 mass) %) 98.8 parts by mass were stirred and brought to 25 ° C.
To this mixed solution, 1.2 parts by mass of 0.5 mol / L hydrochloric acid was added to hydrolyze tetraethoxysilane. By stirring at 25 ° C. for 30 minutes, a tetraalkoxysilane hydrolyzate was obtained as component (a). This tetraalkoxysilane hydrolyzate has a peak area of -70 ppm to -80 ppm when the ²⁹ Si-NMR spectrum is tetramethylsilane (TMS) as a reference substance and the total peak area of -70 ppm to -106 ppm is 100. The ratio is 2.7%, the peak area ratio in the −81 ppm to −87 ppm region is 38.7%, the peak area ratio in the −88 ppm to −96 ppm region is 49.7%, and the peak area ratio in the −97 ppm to −106 ppm region is It was 8.8%.
Next, 56.3 parts by mass of a water / isopropyl alcohol 4% solution of polyvinyl alcohol (water / isopropyl alcohol = 95% by mass / 5% by mass) as component (b) was placed in a reactor equipped with a stirrer and stirred. In this solution, 43.7 parts by mass of the above tetraalkoxysilane hydrolyzate was added as component (a) and stirred at 25 ° C. for 20 minutes to obtain the moisture-proof composition of the present invention. The obtained composition was applied to a bar coater no. The film was dried at 25 ° C. for 5 minutes and further dried in an oven at 190 ° C. for 10 minutes to form a coating film, thereby obtaining a moisture-proof sheet.
It was 0.09 g / m < ² > / day when the water-vapor-permeation rate of the obtained moisture-proof sheet | seat was measured.

Example 2
In a four-necked flask equipped with a reflux condenser and a stirrer, a water / isopropyl alcohol / tetraethoxysilane mixed solution (water / isopropyl alcohol / tetraethoxysilane = 38.6 mass% / 52.4 mass% / 9.0 mass) %) 98.8 parts by mass were stirred and brought to 25 ° C.
To this mixed solution, 1.2 parts by mass of 0.5 mol / L hydrochloric acid was added to hydrolyze tetraethoxysilane. By stirring at 25 ° C. for 4 hours, a tetraalkoxysilane hydrolyzate was obtained as component (a). This tetraalkoxysilane hydrolyzate has a peak area of -70 ppm to -80 ppm when the ²⁹ Si-NMR spectrum is tetramethylsilane (TMS) as a reference substance and the total peak area of -70 ppm to -106 ppm is 100. The ratio is 0%, the peak area ratio in the −81 ppm to −87 ppm region is 5.6%, the peak area ratio in the −88 ppm to −96 ppm region is 55.3%, and the peak area ratio in the −97 ppm to −106 ppm region is 39. 0%.
Next, using the tetraalkoxysilane hydrolyzate as the component (a), a moisture-proof composition and a moisture-proof sheet were obtained in the same manner as in Example 1.
It was 0.16 g / m < ² > / day when the water-vapor-permeation rate of the obtained moisture-proof sheet | seat was measured.

Comparative Example 1
In a four-necked flask equipped with a reflux condenser and a stirrer, a water / isopropyl alcohol / tetraethoxysilane mixed solution (water / isopropyl alcohol / tetraethoxysilane = 38.6 mass% / 52.4 mass% / 9.0 mass) %) 98.8 parts by mass were stirred and brought to 25 ° C.
To this mixed solution, 1.2 parts by mass of 0.5 mol / L hydrochloric acid was added to hydrolyze tetraethoxysilane. By stirring at 25 ° C. for 24 hours, a tetraalkoxysilane hydrolyzate was obtained as component (a). This tetraalkoxysilane hydrolyzate has a peak area of -70 ppm to -80 ppm when the ²⁹ Si-NMR spectrum is tetramethylsilane (TMS) as a reference substance and the total peak area of -70 ppm to -106 ppm is 100. The ratio is 0%, the peak area ratio in the -81 ppm- to 87 ppm region is 0%, the peak area ratio in the -88 ppm to -96 ppm region is 35.5%, and the peak area ratio in the -97 ppm to -106 ppm region is 64.5% Met.
Next, using the tetraalkoxysilane hydrolyzate as the component (a), a moisture-proof composition and a moisture-proof sheet were obtained in the same manner as in Example 1.
It was 0.50 g / m < ² > / day when the water-vapor-permeation rate of the obtained moisture-proof sheet | seat was measured.

Comparative Example 2
In a four-necked flask equipped with a reflux condenser and a stirrer, a water / isopropyl alcohol / tetraethoxysilane mixed solution (water / isopropyl alcohol / tetraethoxysilane = 39.8 mass% / 51.7 mass% / 9.3 mass) %) 96.0 parts by mass were stirred and brought to 25 ° C.
To this mixed solution, 4.0 parts by mass of 4.8 mol / L hydrochloric acid was added to hydrolyze tetraethoxysilane. By stirring at 25 ° C. for 4 hours, a tetraalkoxysilane hydrolyzate was obtained as component (a). This tetraalkoxysilane hydrolyzate has a peak area of -70 ppm to -80 ppm when the ²⁹ Si-NMR spectrum is tetramethylsilane (TMS) as a reference substance and the total peak area of -70 ppm to -106 ppm is 100. The ratio is 0%, the peak area ratio in the -81 ppm to -87 ppm region is 0%, the peak area ratio in the -88 ppm to -96 ppm region is 17.9%, and the peak area ratio in the -97 ppm to -106 ppm region is 82.1% Met.
Next, using the tetraalkoxysilane hydrolyzate as the component (a), a moisture-proof composition and a moisture-proof sheet were obtained in the same manner as in Example 1.
It was 0.66 g / m < ² > / day when the water-vapor-permeation rate of the obtained moisture-proof sheet | seat was measured.

  As is clear from comparison of the water vapor transmission rates of Examples 1 and 2 and Comparative Examples 1 and 2, the moisture-proof composition and moisture-proof sheet of the present invention exhibit excellent water vapor barrier properties.

  The moisture-proof composition and moisture-proof sheet of the present invention are suitably used as a moisture-proof packaging film for various uses such as foods, electronic members, and medical members.

Claims (2)

Tetraalkoxysilane, water and alcohol are mixed, an acidic catalyst is added to the mixture, and the tetraalkoxysilane is hydrolyzed to obtain a tetraalkoxysilane hydrolyzate. The resulting tetraalkoxysilane hydrolyzate and polyvinyl A method for producing a moisture-proof sheet in which a moisture-proof composition containing a reaction product obtained by reacting with an alcohol is laminated on a base film to form a moisture-proof composition layer, wherein the tetraalkoxysilane comprises , At least one silane selected from silanes represented by the following general formula (I), and unsubstituted silicon and monosubstituted with respect to the total number of unsubstituted silicon and 1-3 substituted silicon in the tetraalkoxysilane hydrolyzate Quantity ratio of silicon = {(number of unsubstituted silicon + 1 number of substituted silicon) / (number of unsubstituted silicon + 1-3 number of substituted silicon)} × 1 0 (%) is Ri der 5% or more, the laminated metal thin film layer and / or an inorganic compound thin layer between the moisture barrier composition layer and the substrate film, method of manufacturing the moisture-proof sheet.

(In the formula, R ¹ , R ² , R ³ and R ⁴ are each an alkyl group having 1 to 4 carbon atoms and may be the same or different.)   The method for producing a moisture-proof sheet according to claim 1, wherein the base film is made of a polyester resin and / or a polyamide resin.