JP2022157645A - Composite membrane having low moisture permeability, laminate using the same, and method for manufacturing laminate - Google Patents

Abstract

To provide a composite membrane having low moisture permeability and low environmental loads, a laminate using the same, and a method for manufacturing the same.SOLUTION: A composite membrane contains a resin having an OH group, and a hydrolysis polycondensate of alkoxysilane and/or its condensate.SELECTED DRAWING: None

Description

The present invention relates to membranes with low moisture permeability.

Conventionally, in order to obtain a film or package with low moisture permeability, it is necessary to use a resin with low moisture permeability, or to assist a deposited metal oxide film such as aluminum oxide or silicon dioxide under the organic compound layer. there were.

For example, Patent Document 1 discloses forming a deposited film containing alumina, silica, or the like on the surface of a polyester film, and Patent Document 2 discloses a film in which a specific aluminum oxide film is provided on a plastic substrate. disclosed. Further, Patent Document 3 discloses a gas barrier film using silicon nitride, which is transparent but cannot be easily produced.

JP-A-2005-053223 Japanese Patent Application Laid-Open No. 2021-45929 Patent No. 5394867

However, these vapor deposition films have drawbacks such as lack of transparency and easy entry of impurities during the vapor deposition process. Moreover, vapor deposition itself is not a simple process, and it is not easy to apply it over a wide area. Also, resins with low moisture permeability decompose very slowly in normal environments. For this reason, when used as wrapping paper, etc., if it is left in the environment by being blown away by the wind, it becomes a source of microplastics, etc., so it is possible to reduce the burden on the environment when left unattended. It has been demanded.
An object of the present invention is to provide a resin film having low moisture permeability without laminating a gas barrier film such as a metal deposition film.

Therefore, the present invention has found that these problems can be solved by using a specific composite film as a resin, and a resin film having excellent water vapor barrier properties can be provided.
That is, the gist of the present invention is as follows.

[1] A composite film containing a resin having an OH group and an alkoxysilane and/or a hydrolytic polycondensate of a condensate thereof.
[2] A composite film containing a resin having an OH group and silica particles having a particle size of 15 nm or less.
[3] The composite membrane according to [1] or [2], wherein the OH group is an alcoholic hydroxyl group or a carboxyl group.
[4] The composite membrane according to [1], wherein the alkoxysilane and/or the hydrolyzed condensate thereof are silica particles having an average particle size of 15 nm or less.
[5] The composite membrane according to any one of [1] to [4], which has a moisture permeability of 20 g/m ² ·day or less at 25°C and 90% RH.
[6] A laminate comprising the composite film according to any one of [1] to [5] laminated on a substrate. [7] The laminate according to [6], which has a moisture permeability of 20 g/m ² ·day or less at 25°C and 90% RH.
[8] The substrate is selected from the group consisting of polyethylene terephthalate, polycarbonate, polylactic acid, polybutylene succinate, acrylic resin, PVA, paper, nonwoven fabric, polyethersulfone, polypropylene, polyethylene, polyimide, and cellulose triacetate. The laminate according to [6] or [7].
[9] A step of mixing a solution containing an alkoxysilane and/or a hydrolytic polycondensate of its condensate with a resin having an OH group to form a composite liquid, and applying the obtained composite liquid to a substrate. and a drying step of drying the base material to which the composite liquid has been applied.
[10] The method for producing a laminate according to [9], wherein the drying step is performed at 90°C or higher.

According to the present invention, a composite film (also referred to as a hybrid film) having water vapor barrier properties can be provided without using a vapor deposited metal oxide layer. It is also easy to manufacture, since it does not need to use vapor deposition. In a preferred embodiment, the composite membrane can be made of biodegradable material and silica (sand), so by selecting a biodegradable resin as the base material, the impact on the environment due to residual plastic can be reduced.

Therefore, the present invention can be applied to various fields such as food, beverages, and pharmaceuticals. is the body.

One aspect of the present invention is a composite film containing a resin having an OH group and a hydrolytic polycondensate of an alkoxysilane and/or a condensate thereof.
A similar effect can also be obtained by forming a composite film containing a resin having an OH group and silica particles having a particle size of 15 nm or less.

The compounding of the composite membrane referred to in the present invention means that the OH groups of the hydrolytic polycondensate of a resin having an OH group and an alkoxysilane and/or a condensate thereof undergo a transesterification reaction to form Si—O—C A state in which a bond is formed. In addition, the laminate referred to in the present invention refers to a multilayer body obtained by coating a support such as a substrate with a composite membrane.
(Resin having OH group)
The resin having an OH group used in the present invention is a resin that reacts with the OH group present in the alkoxysilane and/or its decomposition condensate to form a state in which silicon and the resin are chemically bonded. Therefore, the OH group is preferably a carboxyl group or an alcoholic hydroxyl group, more preferably an alcoholic hydroxyl group.

As a specific resin, a biodegradable resin is preferable. Regarding the specific definition of biodegradability, the Biodegradable Plastic Study Group in 1989 defined it as "a plastic that decomposes into low-molecular-weight compounds that do not adversely affect the environment through the involvement of microorganisms in the natural world." rice field. This term is ambiguous, and at the 1993 Annapolis Summit, it was stated that ``biodegradable materials are materials that are completely consumed by microorganisms and produce only natural by-products (carbon dioxide, methane, water, biomass, etc.)''. there is Specifically preferred resins are those selected from the group consisting of polyvinyl alcohol resins, starch, cellulose, lignin, PBS (polybutylene succinate), and PLA (polylactic acid), most preferably polyvinyl alcohol resins.

The specific structure of the polyvinyl alcohol resin (hereinafter sometimes referred to as PVA-based resin) is not particularly limited as long as it is a resin having a vinyl alcohol structural unit. Although it can be obtained by saponifying polycarboxylic acid vinyl ester obtained by polymerizing an ester monomer, it is not limited to this.
Examples of the PVA-based resin include unmodified PVA and modified PVA-based resin. The modified PVA-based resin may be a copolymerized modified PVA-based resin synthesized by copolymerizing a monomer other than a vinyl ester-based monomer that provides a PVA structural unit, or may be a copolymerized modified PVA-based resin synthesized by synthesizing an unmodified PVA. It may be a modified PVA-based resin after modifying the chain or side chain with an appropriate compound.

Examples of copolymerizable monomers (unsaturated monomers) that can be used in the copolymerized modified PVA resin include olefins such as ethylene, propylene, isobutylene, α-octene, α-dodecene, and α-octadecene; hydroxy group-containing α-olefins such as buten-1-ol, 4-penten-1-ol, 5-hexene-1-ol and derivatives such as acylated products thereof; acrylic acid, methacrylic acid, crotonic acid, maleic acid, Unsaturated acids such as maleic anhydride, itaconic acid and undecylenic acid or salts thereof; monoesters or dialkyl esters; amides such as diacetoneacrylamide, acrylamide and methacrylamide; ethylenesulfonic acid, allylsulfonic acid, methallylsulfonic acid olefin sulfonic acids or salts thereof; quaternary ammonium salts such as diallyldimethylammonium chloride and diallyldiethylammonium bromide; substituted vinyl acetates such as isopropenyl acetate and 1-methoxyvinyl acetate; polyethylene glycol allyl ether, methoxypolyethylene glycol allyl allyl ether having a poly(oxyalkylene) group such as ether, polypropylene glycol allyl ether, polyethylene glycol-polypropylene glycol allyl ether;

Copolymerized modified PVA-based resins include PVA-based resins having primary hydroxyl groups in side chains. Examples of such PVA-based resins include side chain 1,2-diol-modified PVA-based resins obtained by copolymerizing 3,4-diacetoxy-1-butene, vinylethylene carbonate, glycerin monoallyl ether, and the like; Hydroxymethylvinylidene diacetate such as diacetoxy-2-methylenepropane, 1,3-dipropionyloxy-2-methylenepropane, 1,3-dibutyronyloxy-2-methylenepropane; A PVA-based resin having a hydroxymethyl group in the resulting side chain can be mentioned.
As a method for post-modifying the post-modified PVA-based resin, unmodified PVA or the modified PVA-based resin is subjected to acetoacetic esterification, acetalization, urethanization, etherification, grafting, phosphate esterification, or oxyalkylenation. etc.

In the present embodiment, both the above-mentioned unmodified PVA and modified PVA-based resins can be used, but in the case of unmodified PVA, a completely saponified product, and in the case of modified PVA-based resin, functional groups with excellent hydrophilicity in side chains, For example, an anionic modifying group-containing PVA having a carboxylic acid group or a sulfonic acid group, a cationic modifying group-containing PVA having a quaternary ammonium base or the like, and a nonionic modifying group-containing PVA having a hydroxyalkyl group or an oxyethylene group are preferable.

When considering the amount of OH groups that react with silanol groups as important, unmodified PVA is particularly preferable because of its high reactivity with silicate, which will be described later. When emphasizing the compatibility of the silicate and PVA solution, it is preferable to use a partially saponified product, and when emphasizing the bond between the silicate and PVA, that is, the Si—O—C bond, a fully saponified product is used. preferable.

The saponification degree of the PVA-based resin is usually 70 mol % or more, preferably 80 mol % or more, more preferably 98 mol % or more. The upper limit is usually 100 mol% or less, preferably 99.8 mol% or less. The degree of saponification is a value measured by the titration method of JIS K6726.
Although the average degree of polymerization of the PVA-based resin is not particularly limited, it is usually 200 or more and 3000 or less, preferably 250 or more and 2800 or less, and particularly preferably 300 or more and 2600 or less.
By setting it in this range, the time required for elution of the coated fertilizer can be lengthened. Also, it is usually 3500 or less, preferably 2800 or less, more preferably 500 or less. This range prevents the elution of the coated fertilizer from becoming too small, and makes it easier to prevent cracking of the coating film. This average degree of polymerization is a value measured by an aqueous solution viscosity measurement method (JIS K 6726).

As the PVA-based resin, only one resin may be used, or two or more resins may be blended and used. In this case, the structural units may differ, the degree of saponification may differ, and the average degree of polymerization may differ. The degree of saponification, the average degree of polymerization, etc. in the case of blending and using may be such that the average values of all the PVA-based resins are within the above ranges.

Moreover, the PVA-based resin may be partially modified. When denatured, the modification rate of the PVA-based resin is 60 after mixing 10 g of the resin particles with 100 g of water at 20° C. and dispersing them by stirring, and then raising the temperature to 90° C. at 1° C./min while stirring. A range in which 90% by weight or more is dissolved within minutes is preferable.
The type of modification is not particularly limited as long as it has an OH group, but when introducing a group having strong acidity or basicity in water, the amount of modification should be within a range that does not have a catalytic effect in the process of combining with silicate. is preferred.

(Alkoxysilane and/or its condensate)
The alkoxysilane and/or condensates thereof used in the present invention bond with resins having OH groups to form Si--O--C bonds.
Alkoxysilane is not particularly limited as long as it is a silane having an alkoxy group. Examples of alkoxy groups include aliphatic alkoxy groups having 1 to 10 carbon atoms such as methoxy, ethoxy, propoxy, and butoxy, phenoxy, aryloxy. aromatic alkoxy groups having 6 to 15 carbon atoms such as groups. Aliphatic alkoxy groups having 1 to 4 carbon atoms are desirable in terms of ease of hydrolysis reaction control.
Alkoxysilanes include monoalkoxysilanes, dialkoxysilanes, trialkoxysilanes, and tetraalkoxysilanes. More specifically, tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane,

Also, trialkoxysilanes having a hydrosilyl group such as trimethoxysilane: methyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, aryltriethoxysilane, aryltrimethoxysilane, 3-( 2-aminoethylamino)propyltriethoxysilane, 3-(2-aminoethylamino)propyltrimethoxysilane, [3-(6-aminohexylamino)propyl]trimethoxysilane, 3-aminopropyltriethoxysilane, 3 -aminopropyltrimethoxysilane, (11-azidodecyl)trimethoxysilane, benzyltriethoxysilane, 1,3-bis(triethoxysilyl)ethane, 1,3-bis(triethoxysilyl)hexane, 1,3-bis Alkyltrialkoxysilanes such as (trimethoxysilyl)ethane, 1,6-bis(trimethoxysilyl)hexane, bis[3-(trimethoxysilyl)propyl]amine, butyltriethoxysilane, cyclohexyltrimethoxysilane, cyclopentyltrimethoxysilane, decyltrimethoxysilane, [3-(diethylamino)propyl]trimethoxysilane, [3-(N,N-dimethylamino)propyl]trimethoxysilane, dodecyltriethoxysilane, dodecyltrimethoxysilane, 2 -(3,4-epoxycyclohexyl)ethyltrimethoxysilane, ethyltrimethoxysilane, [8-(glycidyloxy)-n-octyl]trimethoxysilane, 3-glycidyloxypropyltrimethoxysilane, hexadecyltrimethoxysilane, hexyltriethoxysilane, hexyltrimethoxysilane, octadecyltriethoxysilane, octadecyltrimethoxysilane, 2-propynyl[3-(triethoxysilyl)propyl]carbamate, triethoxy(3-glycidyloxypropyl)silane, triethoxy(isobutyl) Silane, triethoxy-n-octylsilane, triethoxy[2-(7-oxabicyclo[4,1,0]heptan-3-yl)ethyl]silane, triethoxy(propyl)silane, triethoxysilane, (triethoxysilyl) Methyl methacrylate, 3-(triethoxysilyl)propyl methacrylate, 2-[3-(triethoxysilyl)propyl]succinic anhydride, 1-[3-(triethoxysilyl)propyl]urea, triethoxy Di(p-tolyl)silane, triethoxyvinylsilane, triisopropoxy(vinyl)silane, trimethoxy[3-(methylamino)propyl]silane, trimethoxy(7-octen-1-yl)silane, trimethoxy-n-octylsilane , trimethoxy[3-(phenylamino)propyl]silane, trimethoxy(propyl)silane, trimethoxysilane, 1-(trimethoxysilyl)naphthalene, 3-(trimethoxysilyl)propyl acrylate, N-[3-(trimethoxy silyl)propyl]butan-1-amine, 3-(trimethoxysilyl)propyl methacrylate, [3-(trimethoxysilyl)propyl]succinic anhydride, 1-[3-(trimethoxysilyl)propyl]urea, triethoxy (p-tolyl)silane, trimethoxy(4-vinylphenyl)silane, vinyltrimethoxysilane, etc.

Also, dialkoxysilanes such as dimethyldimethoxysilane: dimethyldiethoxysilane, dimethyldimethoxysilane, diphenyldimethoxysilane, 3-diglycidyloxypropyl(dimethoxy)silane, 3-diglycidyloxypropyl(diethoxy)silane, 3- [Dimethoxy(methyl)silyl]propyl methanolate, 3-aminopropyldimethoxymethylsilane, dimethoxy(methyl)silane, dimethoxymethylvinylsilane, cyclohexyl(dimethoxy)methylsilane, 1,1,3,3,5,5,-hexa Ethoxy-1,3,5-trisilylacrohexane, 3-(2-aminoethylamino)propyldimethoxymethylsilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldiethoxymethylsilane, dicyclopentyl(dimethoxy) Silane, diethoxydiethylsilane, diethoxydiphenylsilane, diethoxy(3-glycidyloxypropyl)methylsilane, diethoxy(methyl)phenylsilane, diethoxymethylsilane, 3-[diethoxy(methyl)silyl]propyl methacrylate, diethoxymethyl vinylsilane, diisobutyldimethoxysilane, dimethoxydi-p-tolylsilane, dimethoxy(methyl)-n-octylsilane, dimethoxymethylphenylsilane, dimethoxy(methyl)silane, 3-[dimethoxy(methyl)silyl]propyl acrylate, 3-glycidyloxy such as propyl(dimethoxy)methylsilane,

Also, monoalkoxysilanes: aryloxytrimethylsilane, benzyloxytrimethylsilane, 3,5-bis(tert-butyldiphenylsilyloxy)benzyl alcohol, 1,2-bis(trimethylsilyloxy)cyclobutene, bis[2-(trimethylsilyl oxy)ethyl] ether, 1,3-bis(trimethylsilyloxy)propane, tert-butoxytrimethylsilane, (1E)-1-tert-butoxy-1-(trimethylsilyloxy)propane, dimethylethoxyvinylsilane, dimethylketene methyltrimethylsilyl acetal , ethoxytriethylsilane, ethoxytriphenylsilane, ethylenedioxybis(trimethylsilane), isopropenyloxytrimethylsilane, isopropoxytrimethylsilane, methoxy(dimethyl)octadecylsilane, methoxy(dimethyl)-n-octylsilane, methoxydimethylphenyl Silane, methoxytrimethylsilane, 1-methoxy-1-trimethylsilyloxypropene, methoxytriphenylsilane, trimethylethoxysilane, trimethyl(phenoxy)silane, 2-(trimethylsilyloxy)furan, trimethoxy(vinyloxy)silane, tris(trimethylsilyloxy) and ethylene. Although there is no particular limitation among these, it is preferable to have a biodegradable functional group.

Among these, tetraalkoxysilanes and trialkoxysilanes are preferred, and tetraalkoxysilanes are more preferred, from the viewpoint of low moisture permeability when composite particles with a resin having an OH group are formed. These alkoxysilanes may be used alone or in combination of two or more. In particular, it is preferable to use both tetraalkoxysilane and trialkoxysilane because cracking of the film is less likely to occur.

From the viewpoint of the object of the present invention to provide a composite film with low moisture permeability, monoalkoxysilane and dialkoxysilane, which are low crosslinkable components, are used as additives for imparting functionality, and OH groups in composite particles are used. It is preferable to use the minimum amount that does not promote swelling or dissolution of the resin component.

Alkoxysilane and/or its condensate hydrolyzes in a solvent to form a three-dimensional siloxane crosslinked structure as a hydrolytic polycondensate. The condensate of alkoxysilane may be a low condensate. The term "low condensate" as used herein means an oligomer of about 2- to 10-mer of alkoxysilane, and may be an oligomer of about 2- to 8-mer, or may be an oligomer of about 2- to 5-mer. As the solvent, lower alcohols having 1 to 4 carbon atoms, such as methanol, ethanol and propanol, and mixtures thereof with water are usually used.

The component containing alkoxysilane / or its condensate contained in the composite film of the present embodiment is usually 50% by weight or more, and 70% by weight or more in terms of _SiO2 , as the Si content with respect to the total weight of the composite film. It is preferably 100% by weight or less, preferably 90% by weight or less. The Si content with respect to the total weight of the composite film will be explained later in the description of <composite film>.

The alkoxysilane and/or the hydrolyzed condensate of its condensate used in the present invention preferably has a certain particle size. If the particle size is too small, a sufficient three-dimensional siloxane crosslinked structure cannot be obtained, and swelling of the resin having an OH group cannot be suppressed. The amount of bases decreases, and as a result, a dense three-dimensional siloxane structure cannot be obtained, and low moisture permeability cannot be obtained. The particle size for obtaining good low moisture permeability is preferably 15 nm or less, more preferably 12 nm or less, even more preferably 9 nm or less, particularly preferably 6 nm or less, and most preferably 3 nm or less. As a result, a Si--O--C bond, which will be described later, can be formed with the resin having an OH group, a three-dimensional crosslinked structure can be formed, and low moisture permeability can be obtained. Examples of the method for measuring the particle size of the hydrolyzed condensate of alkoxysilane and/or its condensate include a particle size distribution measuring device using a dynamic light scattering method. It can also be obtained by measuring by a method using

The resulting composite film preferably has a Si--O--C structure. This Si--O--C structure can be confirmed by Fourier transform infrared spectroscopy.
A method for confirming the presence of a Si—O—C bond in Fourier transform infrared spectroscopy (hereinafter referred to as FT-IR) is as follows. FT-IR measurement reveals the vibrational mode of each atomic group in the region of 1500 to 1200 cm ⁻¹ . According to Hitachi Review, Vol. 43, No. 5, 90-94 (S36.5), at 1430 ± 30 and 1326 ± 25 cm ^-1 there is coupling between the bending vibration of the OH group in PVA and other vibrations. appear. Silicate has no peak in the region between 2000 cm ⁻¹ and 1300 cm ⁻¹ . From this, it can be seen that when the Si--O--C structure is formed in the composite film, the number of OH groups is reduced and the coupling with other vibrations is reduced, so that this peak is reduced or disappeared.

The sample to be measured by FT-IR varies depending on the method of measurement, but the state of the film coated on the substrate described later or a single film prepared under the same conditions as the film coated on the substrate is used for measurement. can do When it is necessary to measure quickly, it is preferable to measure the state of the film coated on the substrate, and when it is necessary to analyze with high accuracy, it is preferable to measure the film alone.
When the film coated on the substrate is measured, it may be measured as it is, or it may be dried before the measurement. Although the drying temperature is not particularly specified, it is preferable not to affect the amount of Si--O--C bonds in the film. In this case, the temperature is preferably 120° C. or lower, more preferably 100° C. or lower, still more preferably 80° C. or lower, and most preferably 60° C. or lower. The drying time can be appropriately changed depending on the drying temperature. A single film can be obtained by adding usually 1 g of a coating liquid having the same composition as that of the film coated on the substrate onto a PTFE petri dish and applying the same drying and baking conditions as those for the film coated on the substrate.

Measurement methods include a transmission method and a reflection method, but the reflection method is preferred, and among the reflection methods, the ATR method, which is not affected by the shape of the sample to be measured, is particularly preferred. When the ATR method is used for measurement, a diamond prism is most preferable in terms of the measurable wavenumber region.

When analyzing with FT-IR, it is possible to obtain data by accumulating by one measurement. Accuracy of the obtained spectrum is improved by performing integration, and highly reliable values can be obtained. The number of accumulations is 2 to the nth power. Although the number of times is not particularly limited, it is preferably 32 times or more, particularly preferably 64 times or more, and most preferably 128 times or more.
Also, it is preferable to set the resolution of the spectrum to be measured. As the resolution is set smaller, the accuracy of the spectrum improves, and highly reliable values can be obtained. Although there is no particular limitation on the resolution setting value, it is preferably 32 cm ⁻¹ or less, more preferably 16 cm ⁻¹ or less, still more preferably 8 cm ⁻¹ or less, particularly preferably 4 cm ⁻¹ or less, and most preferably 2 cm ⁻¹ . It is below.

FT-IR preferably performs background measurement when measuring the object to be measured. Background measurement refers to correction for subtracting absorption components such as water vapor and carbon dioxide in the air. This eliminates measurement errors due to moisture and carbon dioxide in the air. A background measurement is taken prior to measurement.
The spectrum obtained by FT-IR is phase-corrected. Phase correction is automatically corrected by the FT-IR software during measurement. The method of phase correction is not particularly limited, but includes the absolute value method, multiplication method, convolution method, manual method, etc., and the method can be selected according to the characteristics of the sample to be measured. For example, in the case of an apparatus iN10MX manufactured by Thermo Fisher Scientific, the Mertz method or the Power Spectrum method can be selected. The Mertz method is usually used unless there are clearly strange results.

The intensity of the spectrum obtained by FT-IR is expressed as absorbance.
Baseline correction is performed when the spectrum obtained by FT-IR appears in absorbance. This is because an accurate peak intensity ratio and area value cannot be obtained when the baseline of the obtained spectrum is disturbed. The baseline correction method is not particularly limited, and an appropriate method is used according to the obtained spectrum. For example, Thermo Fisher Scientific software OMNIC (Version 8.3 or later) analyzes the obtained spectrum and automatically selects the most preferable correction method. The applicable software allows selection of linear (primary) interpolation, cubic spline interpolation (spline), and polynomial interpolation.

The spectrum obtained by FT-IR is smoothed. This is to prevent minute disturbances in the spectrum from being detected as peaks when performing peak separation, which will be described later. By performing smoothing, minute disturbances can be arranged, and more accurate peak separation calculation can be performed. The smoothing method is not particularly limited, and includes a simple moving average method, a Sacutzkey-Golay method, and the like, and an appropriate method is used depending on the spectrum obtained and, in the case of automation, the software used. For example, Thermo Fisher Scientific software OMNIC (Version 8.3 or later) analyzes the obtained spectrum and automatically selects the most preferable range. In addition, the corresponding software allows you to specify the interval between wavenumbers when performing smoothing. If the specified wavenumber interval is small, smoothing is performed while maintaining the shape of the original spectrum, but the spectral lines are not sufficiently smoothed. Conversely, if the specified wavenumber interval is large, the spectral line will be smoother, but the shape of the original spectrum will be changed. Therefore, it is important to specify an appropriate interval for smoothing. The specified interval is preferably 9.642 cm ⁻¹ or more and 48.212 cm ⁻¹ or less, but if it is considered that the influence of noise or impurities is large, it should be in the range of 13.499 cm ⁻¹ or more and 28.927 cm ⁻¹ or less. can be smoothed without losing spectral peaks.

A spectrum obtained by FT-IR is subjected to peak separation. This is because it is possible to prevent the actual peak intensity from increasing due to overlapping of peaks, making it impossible to make an accurate evaluation, and it is possible to calculate the Si—O—C bond from the area ratio of the separated peaks, which will be described later. be. There are various methods and techniques for peak separation, and automatic calculation using software is also possible. In the present invention, the software OMNIC (Version.8.3 or later) of Thermo Fisher Scientific was used for peak separation.

Specify the wave number to separate when detecting peaks with the software. The range used for drawing the baseline may be used as the specified range, and the range from 4000 cm ⁻¹ to 400 cm ⁻¹ is used. A range of 2000 cm ⁻¹ to 800 cm ⁻¹ is used if a baseline in this range is deemed inappropriate. Also, when detecting peaks in the specified range, set the initial value of the peaks to be detected. Peak detection is normally performed within the specified range by setting the half-value width to 3.857. At this time, peaks detected due to baseline disturbance may be removed. Voigt is usually used as a distribution function for peak detection, but Gaussian, Lorentzian, Gaussian-Lorentzian, and Log Normal are used depending on the situation. Also, it is possible to set the sensitivity for detecting the peak at the set half width. Normally, the sensitivity is set to low sensitivity using the program attached to the device to prevent unnecessary peak detection, but it is possible to set medium sensitivity or high sensitivity when peaks are not detected. Peak fitting is performed using the detected peaks. At this time, the permissible range of the standard deviation values of the original spectrum and the synthesized spectrum obtained can be set in advance and calculated. Treat this tolerance as noise. The noise can be set from 1 to 10, the higher the value the larger the standard deviation value i.e. the difference between the resulting synthesized spectrum and the original spectrum is larger, the lower the value the smaller the standard deviation value i.e. It becomes easier to obtain a spectrum in which the synthesized spectrum and the original spectrum match. The noise setting value is usually 10, but the value may be decreased when the standard deviation value of the synthesized spectrum obtained is large. Baseline correction can also be performed during peak fitting. Normally, first-order (linear) correction is performed, but second-order and third-order corrections can be performed depending on the synthesized spectrum obtained. The software used repeats the calculations, so even if the standard deviation value of the synthesized spectrum obtained in the first calculation is larger than the standard, by performing the calculation again under the same conditions, a synthesized spectrum closer to the original spectrum can be obtained. Calculate A composite spectrum as used herein refers to an IR spectrum obtained by summing the calculated isolated spectra. If the standard deviation value exceeds the standard even after repeated calculations, the half-value width of the peak to be detected may be different. Repeat this work and calculation until the deviation value is below the reference value. The standard deviation value is preferably 1.5 or less, but it is better to keep it as small as possible. range, most preferably 0.5 or less.

The software generally used in the present invention is Version. 8.3 or later OMINIC, any software capable of peak detection and calculation by setting the half width can be used.
By comparing the peak area of the stretching vibration of the Si—O—Si bond appearing at 1050 cm ⁻¹ ± 25 in the composite film and the peak area near 1430 ± 30 cm ⁻¹ or 1326 ± 25 cm ⁻¹ , the Si—O—C bond can be detected. can be confirmed. At this time, the wave number of each peak top may deviate depending on the measurement conditions and the state of the sample. The peak areas to be used can be compared with the area values of the isolated peaks calculated from the synthetic spectrum with a standard deviation of 1.0 or less. When the ratio of spectral peaks is PVA/Si—O—Si, the peak of PVA used is usually the peak at 1430 cm ⁻¹ , but when the detection sensitivity of the peak at 1430 cm ⁻¹ is low or the influence of other vibrational peaks is avoided. There is no problem using the peak at 1326 cm ⁻¹ when receiving. The smaller the value of PVA/Si—O—Si, the more Si—O—C bonds are formed, and the value is preferably 0.2 or less, more preferably 0.15 or less, and 0.1 Most preferred are:

In FT-IR, if the peak at 1430 ± 30 cm ^-1 or 1326 ± 25 cm ^-1 is not detected, or if the influence of baseline disturbance or spectral noise is large and accurate values cannot be obtained, ¹ H This problem can be solved by using nuclear magnetic resonance spectroscopy (hereinafter, ¹ H NMR).
Solution ¹ H NMR usually shows peaks due to dissolved species and no peaks for insoluble components. In addition, when OH and Si--OH of PVA are bonded through covalent bonds, they form a three-dimensional network structure and become insoluble in all solvents. Therefore, when the OH and Si—OH of PVA are bonded via a covalent bond, the peak due to ¹ H in PVA is no longer observed in solution ¹ H NMR, or the amount of PVA in the composite film indicates It is observed weaker than the peak intensity.

Since the measurement form is a solution, the form of the object to be measured for measurement is preferably a single film prepared by extracting the film from the substrate or under the same conditions as the film coated on the substrate. For the film coated on the substrate, in addition to obtaining a value by measuring the density of a single film according to JIS8807:2012, the weight per unit area is calculated from the film thickness of the coating film and the density of the composition of the film. can be done.

When preparing a measurement sample from the coating film of the base material, the cut base material is immersed in an organic solvent or water, and then the solvent is dried to obtain an eluted coating film. There is a method in which the substrate is immersed in the heavy solvent to be used and then taken out to obtain the heavy solvent containing the coating film. Measurement is possible with either method, but if analysis accuracy is important, it is preferable to extract the coating film with an organic solvent or water. The preferred method is to Each method will be explained.

When the cut substrate is immersed in an organic solvent or water, 50000% by weight of the organic solvent or water is added to 100% by weight of the coating film present on the cut substrate, and the substrate is immersed. At this time, the substrate may be immersed in either a shallow container such as a petri dish or a deep container such as a screw tube. Any solvent may be used as long as it dissolves the resin having an OH group that has not reacted with SiOH in the basic coating film and does not dissolve the substrate. For example, if the resin used is PVA, DMSO, water, and the like can be used. There is no specific time period for lack of extraction, but it is immersed for at least 30 minutes. When extracting with these solvents, the temperature may be increased as long as it does not affect the Si--O--C bond. This can accelerate the elution of the coating film on the substrate.

The temperature varies depending on the boiling point of the organic solvent, but is not particularly defined as long as it does not affect the Si--O--C bond. For example, in the case of water, the temperature at which the membrane is eluted is preferably 1° C. or higher and 100° C. or lower, more preferably 5° C. or higher and 95° C. or lower, further preferably 10° C. or higher and 80° C. or lower, and particularly preferably 15° C. or higher and 75° C. or lower. 20° C. or higher and 60° C. or lower is most preferable. By setting it within this range, it is possible to reduce the influence on the amount of Si--O--C bonds in the film.
The heating time varies depending on the temperature at that time. When the immersed substrate is removed, it is preferable to wash both sides of the substrate. The purpose of this is to collect the components of the coating film that may have adhered when the substrate is pulled up.
The solvent used for washing is usually the solvent used when the substrate was immersed, but other organic solvents or water may be used as long as they are compatible. There are no restrictions on the solvent used for washing, as long as a sufficient amount of eluate can be recovered from the base material for use in analysis.

Next, the process of removing the solvent used for relatives of the substrate and the solvent used for washing will be described. In this step, the solvent containing the eluted coating film is removed by heating or under reduced pressure to obtain the recovered film components. In this process, there are methods using devices such as constant temperature chambers, dryers, and rotary evaporators, and methods in which the solvent is dropped onto a watch glass and heated with a burner to remove the solvent. is preferred, and a rotary evaporator is particularly preferred from the standpoint of safety. When depressurizingly distilling with a rotary evaporator, heating may be used. The solvent used in the bath at this time is usually water. The temperature of water is not particularly defined as long as it does not affect the Si--O--C bond, but is preferably 80° C. or less, more preferably 70° C. or less.

After the solvent removal process is completed, the components of the coating film are solidified and precipitated. This is washed with an organic solvent or water in which the coating film is insoluble and compatible with the organic solvent used for the base material, and dried. This task is important when low volatility organic solvents are used for the extraction. As a result, the solvent that could not be completely removed during drying can be removed. Therefore, the organic solvent used for washing is preferably insoluble in the coating film, soluble in the solvent of the recovery liquid, and volatile. There are no particular restrictions as long as these conditions are met, but examples include lower alcohols such as methanol and ethanol, acetone, and aliphatic hydrocarbons.

The precipitate after washing with an organic solvent is preferably dried for a certain period of time. Since a volatile solvent is used, there is usually no problem with drying at room temperature, but when handling water, etc., drying using a device such as a constant temperature chamber may be performed as long as it does not affect the Si—O—C bond. do not have. The drying temperature is preferably a temperature that does not affect the amount of Si--O--C bonds in the film and can remove moisture in the film. This range is preferably 120° C. or lower, more preferably 100° C. or lower, still more preferably 80° C. or lower, and most preferably 60° C. or lower. The drying time can be changed by the drying temperature. Since a solid sample can be obtained by these steps, sampling is performed according to the NMR measurement method described later.

In the method of immersing the cut-out substrate in a heavy solvent, 1500% by weight of the heavy solvent is added to 100% by weight of the coating film present in the cut-out substrate, and the substrate is immersed. The immersion time is not particularly limited, but immersion for 1 minute or more is preferable. At this time, the heavy solvent to be used is preferably a solvent that dissolves the coating film on the substrate but does not dissolve the substrate. Moreover, the method of immersing the base material may be either in a shallow container such as a petri dish or in a deep container such as a screw tube. Any solvent may be used as long as it dissolves the resin having an OH group that has not reacted with SiOH in the basic coating film and does not dissolve the substrate.

A single film can be obtained by adding usually 1 g of a coating liquid having the same composition as that applied to the base material onto a PTFE petri dish, and applying the same drying and baking conditions as when producing the coated granular fertilizer. Alternatively, it is possible to use a substrate on which a coating film can be peeled off after coating, on which a film prepared by the same coating method and conditions and baking conditions is peeled off from the substrate.

The heavy solvent used in the measurement by ¹ H NMR is not particularly limited as long as the composite membrane is soluble, but usually aproton-donating heavy dimethyl sulfoxide (hereinafter, DMSO-d6) solvent is used. . By using this solvent, measurement can be performed without overlapping spectral peaks derived from the film. The ratio of the object to be measured and the heavy solvent is 100% by weight of the composite membrane and 1500% by weight of the heavy solvent. The weights obtained in this sampling are important for integral normalization later, and it is preferable that the weights be as uniform as possible.

When measuring with ¹ H NMR, the spectra obtained are preferably integrated. This is because the integration reduces noise on the spectrum and obtains a smoother and more accurate spectrum. The summation is usually performed in 2^n numerical values. There is no particular limit to the number of accumulations, and the more times you accumulate, the more accurate the spectrum can be obtained. is. It is preferably from 2 times to 128 times, more preferably from 4 times to 128 times, and most preferably from 8 times to 128 times.

When measuring with ¹ H NMR, it is necessary to set a waiting time (Relaxation Delay, hereinafter referred to as RD) for irradiating the next pulse in order to improve measurement accuracy. After the magnetization is excited, it is necessary to return to a thermal equilibrium state, and if it is too early, the next measurement will start before the thermal equilibrium state is sufficiently restored. Therefore, it is desirable to set an appropriate time. It is typically 5 seconds, but may be longer if a more precise spectrum is obtained.

Solution ¹ In HNMR, it is preferable to add a reference substance when preparing a measurement sample in order to integrally normalize peaks due to OH groups of resins having OH groups. Preferably, the reference substance does not overlap the spectrum of the composite membrane or the raw material of the composite membrane, is soluble in the deuterated solvent used, and more preferably is non-volatile. Volatile substances include N,N-dimethylformamide (DMF), benzene, benzaldehyde, acetone, acetonitrile, chloroform, diethyl ether, methyl ethyl ketone (MEK), heptane, hexane, 2-propanol, pyrrole, toluene, triethylamine (TEA ), nonvolatile substances such as dimethylacetamide, grease, hexamethylbenzene (HMB), imidazole, hexamethylphosphoric triamide, and pyridine. Normally, the normalized integrated value of the reference substance is 1, but when the integrated value of the signal due to the OH group of PVA is smaller than 1, it may be calculated and normalized as 10 or 100.

The normalized integral value of the peak due to the OH group of the resin having the OH group contained in the composite film is the normalized integral value of the peak due to the OH group of the PVA alone having the same mass as the PVA contained in the composite film. On the other hand, it is preferably 50% or less, more preferably 40% or less, particularly preferably 30% or less, and most preferably 20% or less. At this value, sufficient Si--O--C bonds are generated to exhibit low moisture permeability.

Although the method for obtaining the composite membrane according to the present embodiment is not particularly limited, it can usually be produced by the procedure shown below.
i) A method using an aqueous hydrolyzed solution of an alkoxysilane and/or its condensate ii) A method using an alkoxysilane and/or its condensate And another form of the present invention is an alkoxysilane and/or its condensate and a resin having an OH group to form a composite liquid, applying the resulting composite liquid to a substrate, and applying the composite liquid to the substrate. and a drying step of drying the laminate.
A composite film laminated on a substrate is called a laminate, and the same applies hereinafter.
In the following, as a representative example, (i) will be described using a PVA-based resin as the resin having an OH group. PVA-based resin is one of the most suitable examples in the present invention, but in terms of the structure of the present invention, the resin to be reacted with (i) is not particularly limited as long as it has an OH group, such as cellulose, Cellulose derivatives, starch and the like are also applicable.

A production method using a hydrolyzate of PVA-based resin, alkoxysilane and/or its condensate will be described in detail. In one example, the following steps 1) to 5) can be performed to obtain a laminate in which the composite film of the present invention is laminated and pressed onto a substrate.
1) Preparation of an aqueous solution (A) of an alkoxysilane and/or its condensate 2) Preparation of an aqueous solution (B) of a PVA-based resin 3) Mixing (A) and (B) (step of forming a composite solution)
4) Step of applying to substrate 5) Drying step

1) Preparation of Alkoxysilane and/or its Condensate Aqueous Solution (A) In this step, the alkoxysilane and/or its condensate is mixed with a catalyst and water in the presence or absence of a solvent for hydrolysis, and optionally water A dilutable liquid hydrolyzate composition is provided.
As the solvent, aliphatic lower alcohols having 1 to 4 carbon atoms, such as methanol, ethanol, and propanol, are usually used, but they have high compatibility with water, and precipitation of PVA occurs even when mixed with an aqueous PVA-based resin solution. Particularly preferred are methanol and ethanol, which are difficult to remove. Even if the alkoxysilane and/or its condensate and water for hydrolysis are mixed in the absence of a solvent, they are incompatible, but as the hydrolysis proceeds, the added water is consumed and the corresponding alcohol is produced. If the amount is small, the composition may eventually become uniform and transparent even without solvent. The amount of the solvent used is 60% to 75% by weight with respect to 20% by weight in terms of SiO ₂ of the hydrolyzed alkoxysilane contained in (A). It can be appropriately changed according to the solid content concentration, solvent type, and solvent ratio. After this, dilution may be carried out with water or alcohol so as to obtain the desired concentration, if necessary.

A catalyst and water are used to hydrolyze (and/or condense) the alkoxysilane and/or its condensate during the preparation of the aqueous solution (A).
Such catalysts are generally inorganic acid catalysts such as hydrochloric acid, sulfuric acid, nitric acid and hydrofluoric acid; organic catalysts such as formic acid, acetic acid, maleic acid, fumaric acid and p-toluenesulfonic acid; and basic catalysts such as ammonia. , metal alkoxides, organic tin compounds, metal chelate compounds containing any metal such as aluminum, titanium and zirconium, and boron compounds. The resulting hydrolyzate has many silanol groups, has a high affinity with the PVA-based resin, and the aqueous solution (A) is resistant to gelation in a short time and has excellent storage stability. Alkoxides, metal chelate compounds, boron compounds and the like.

The amount of such a catalyst is generally 0.001 to 0.3 mol%, preferably 0.002 to 0.2 mol%, particularly preferably It is 0.003 to 0.1 mol %. By using such an amount, the hydrolysis reaction proceeds at an appropriate rate and the storage stability of the aqueous solution (A) is enhanced.
The amount of water in preparing the aqueous solution (A) is generally 50 to 200 mol %, preferably 55 to 180 mol %, based on the total molar amount of the alkoxy groups of the alkoxysilane and/or its condensate. With such an amount, the hydrolysis reaction proceeds easily, and when (A) is diluted with water, it tends to be uniformly compatible with water. In addition, it is easy to avoid becoming porous when producing the desired composite membrane, and wasteful heat is not used for drying. A mixture of a catalyst and water is generally blended together with the alkoxysilane/or its condensate, but may be added separately.

The hydrolysis (and/or condensation) reaction of the alkoxysilane and/or its condensate during the preparation of the aqueous solution (A) is usually 10 to 80°C. If the temperature is too high, the hydrolysis reaction rate increases and (A) tends to gel. The reaction is usually carried out with stirring.
Also, the reaction time varies depending on the scale, but is usually 5 minutes to 24 hours, preferably 10 minutes to 8 hours. By setting it to such a time, the aqueous solution (A) is less likely to become highly viscous or gel, and the reaction is prevented from becoming insufficient, so that the aqueous solution (B) and the aqueous solution (B) can easily be transparently dissolved.

2) Preparation of PVA-based resin aqueous solution (B) In this step, PVA-based resin particles are added under stirring to water or a mixed solution of water and methanol, or in a state where these are heated as necessary, to obtain the above-described Resin particles are dissolved in water to obtain a PVA-based resin aqueous solution (B). The temperature of water is 10 to 100° C., particularly preferably 25 to 90° C., and is appropriately selected according to the dissolution characteristics. The PVA-based resin particles may be charged all at once or dividedly. In order to prevent lumps and completely dissolve the powder, the solution may be heated after the addition, if necessary. The mixture may be heated immediately after being added, but if it is stirred at room temperature for a certain period of time and then heated, it is easier to prevent the formation of lumps. The room temperature here refers to a range of 25±5°C. The time for stirring at room temperature is not particularly defined, but it is usually 1 to 3 hours, more preferably 20 to 40 minutes, particularly preferably 10 to 15 minutes, and is appropriately selected according to the properties of the PVA-based resin. . Moreover, you may inject|throw-in while heating.

The concentration of the aqueous solution (B) can be appropriately selected according to the viscosity of the aqueous solution (B), the solubility characteristics of the resin used, and the compatibility with the aqueous solution (A). 25% by weight. The solvent of the aqueous solution (B) is usually water, but it may contain a lower alcohol having 1 to 3 carbon atoms or an organic solvent such as acetone depending on the dissolution characteristics of the resin having an OH group. This results in faster drying of the coating film and faster production of the coated substrate. The content of the organic solvent is generally 1-9900% by weight, more preferably 10-400% by weight, particularly preferably 30-250% by weight, based on 100% by weight of water.

3) Step of making a composite liquid In this step, the aqueous solution (A) and the aqueous solution (B) prepared by the above method are mixed to form a uniform aqueous solution (composite liquid). The method of mixing may be dropwise addition or batch addition.
Here, when the alkoxysilane and/or its condensate in the aqueous solution (A) is in a partially hydrolyzed state, part of the water in (B) is It is used as water for hydrolyzing the silicate component, and further hydrolytic polycondensation proceeds. After the aqueous solution (A) and the aqueous solution (B) are mixed, the mixture is aged for 10 minutes to 24 hours at room temperature or under heating to the boiling point of the mixed liquid or less to obtain a homogeneous aqueous solution.

In addition, other components such as inorganic or organic fillers may be contained in the composite film as long as the low moisture permeability, which is the effect of the present invention, is not impaired. Examples of the filler include plate-like fillers such as talc, mica and hydrotalcite, calcium carbonate, silica, clay, various ore pulverized products, and sulfur.
In addition to fillers, other components include, for example, organic substances such as surfactants, polysaccharides and derivatives thereof. Examples of surfactants include polyethylene glycol, polypropylene glycol, polyalkylene glycol obtained by copolymerization of ethylene glycol and propylene glycol, water-soluble substances such as polyvinyl alcohol, and ethers such as polyethylene glycol-alkyl ether and polyethylene glycol-branched alkyl ether. type nonionic surfactants, polyethylene glycol-alkyl esters, ester-type nonionic surfactants such as polyethylene glycol-branched alkyl esters, cationic surfactants, anionic surfactants, zwitterionic surfactants and A mixture of these and the like are included. Polysaccharides or derivatives thereof include, for example, cellulose, agar, starch, chitin and its derivatives, and chitosan and its derivatives, among which starch is a preferred material due to its low cost. As starch, those derived from corn, tapioca, wheat, potato, rice and sweet potato can be used. Modified starch such as pregelatinized starch may also be used as these starches. In addition, a silicone-treated starch or the like in which the surface of the starch is treated with a silicone resin or the like to improve dispersibility and fluidity can also be used. These surfactants, polysaccharides or derivatives thereof can be used alone or in combination of two or more.

The particle size of the filler is preferably 100 μm or less, more preferably 1 to 50 μm. When the particle size is within the above range, problems such as peeling of the film during film formation due to the particle size being too large are less likely to occur. Even if the particle size of the filler is larger than the thickness of the coating and a part of the filler protrudes from the surface of the coating, the intended purpose can be achieved as long as the filler is partially incorporated into the coating and adheres to the coating. The particle size may be measured using a known method such as the laser diffraction particle size distribution analyzer. When the coating material contains the above fillers, etc., the ratio is not particularly limited, but is preferably 0.1 to 70% by mass, more preferably 1 to 60% by mass, based on 100% by mass of the coating material. When the coating material contains other components other than fillers such as surfactants, polysaccharides and derivatives thereof, the ratio is not particularly limited, but is 0.01 to 0.01 to 100% by mass of the coating material. 60% by mass is preferred, and 0.1 to 50% by mass is more preferred.

4) Step of Applying to Substrate In this step, the composite liquid obtained in the previous step is used to apply to the substrate. Although the bar coating method is used here, the coating method is not particularly limited, and an arbitrary one may be appropriately selected from conventionally known coating techniques. Specifically, spray method, roller coating method, bar coating method, spin coating method, gravure coating method, die coating method, inkjet method, dispenser method, comma coating method, curtain coating method, dip coating method, silk screen printing, flexo A method using various means such as printing can be mentioned. The method can be appropriately selected from the above methods depending on the thickness of the coating, the viscosity of the material, and the solid content. The base material to be used is not particularly limited, but paper, polyethylene, polyethylene terephthalate (PET), nonwoven fabric, polyethylene naphthalate, polyethersulfone, polypropylene, polyimide, polycarbonate, polybutylene succinate, polyvinyl alcohol, cellulose triacetate, etc. can be used. PET is preferable from the viewpoint of film adhesion and low moisture permeability of the substrate, and polybutylene succinate is particularly preferable from the viewpoint of environmental impact. In addition, the smaller the thickness of the substrate, the higher the moisture permeability, so the effects of the present invention are likely to be exhibited. The thickness of the substrate to be used is not particularly limited, but is preferably 100 μm or less, more preferably 75 μm or less, even more preferably 50 μm or less, and particularly preferably 30 μm or less.

Here, a polybutylene succinate film having a thickness of 30 μm is used as a base material to be coated, and the coating is performed by a bar coating method. A base material cut into 15 cm x 11.5 cm squares is pasted on cardboard with cellophane tape on each side. At this time, be careful not to distort the base material. The cardboard to which the base material is pasted is fixed on a horizontal table, and the coating liquid is added in a horizontal straight line on the upper part of the base material. In the bar coating method, the amount of coating liquid to be added is determined by the size of the substrate. Here, if 0.5 g or more and 1 g or less is added, it can be applied uniformly without spots. Coating is then performed using a bar coater. The type of bar coater to be used is not particularly limited, but a wireless bar coater (non-wire bar coater) that is less prone to clogging and has less film thickness unevenness is particularly preferred. Regarding the number of bar coaters, the smaller the theoretical film thickness, the less unevenness in film thickness, and the larger the theoretical film thickness, the thicker the coating film can be obtained. It can be appropriately selected depending on the solid content and viscosity of the liquid. In order to obtain a film thickness that can exhibit the effect of the present invention with less film thickness unevenness, the number is preferably 0.6 or more and 44 or less, more preferably 0.6 or more and 40 or less, and further preferably 1 or more and 29 or less. No. 1 to 26 is particularly preferred, and No. 2 to 22 is particularly preferred. A bar coater is gently placed on top of the base material at the position of the added coating liquid, and rotated in place two or three times so that the coating liquid permeates the entire coater. The bar coater is then pulled straight down to the bottom of the substrate without rotation. By doing so, a coating film having a uniform thickness can be obtained.

5) Drying step In this step, the coating film on the base material obtained in the previous step is dried to cure the coating film, and a film with low moisture permeability can be obtained. The temperature of the drying process is not particularly limited, but drying at a relatively low temperature in order not to cause cracks in the composite film and increasing the Si—O—C bonds in the film make the film more dense and moisture permeable. is preferably combined with drying at elevated temperatures to lower the . Specifically, it may include the following steps (a) and (b).
(A) Low temperature drying (B) High temperature drying The low temperature and high temperature referred to here are names for differentiating (A) and (B).

The device used for drying is not particularly limited as long as it can remove the solvent in the coating film and cure the coating film. For example, a constant temperature oven or a dryer is used, and the constant temperature oven is preferable because it has uniform temperature accuracy. When a dryer is used, a forced circulation dryer and a natural convection dryer can be mentioned, and the forced circulation dryer is preferable because of its excellent temperature accuracy. Here, DKN-402 blower constant temperature incubator manufactured by Yamato Scientific Co., Ltd. is used.

(a) Low temperature drying The temperature at this time is preferably room temperature or higher, preferably 40°C or higher, more preferably 60°C or higher and 89°C or lower. If the temperature is higher than this, the film may crack due to rapid loss of moisture in the film. Although the time required for baking varies depending on the baking temperature, it is preferable to bake for at least 15 minutes.

(b) High-temperature drying This step is a step of baking the coating film baked in (a) at a temperature higher than that in (a). As a result, Si--O--C bonds in the film increase, the film becomes denser, and elution can be suppressed. The drying temperature is not particularly limited as long as it does not affect the substrate, but is preferably 90°C or higher, preferably 100°C or higher and 120°C or lower. Although the time required for high-temperature drying varies depending on the drying temperature, it is preferable to bake for at least 15 minutes or longer.

<Composite membrane>
The composite membrane obtained through the two drying steps preferably has a certain thickness. The thickness is determined by the conditions of the coating method used when coating the base material, the viscosity of the coating liquid, the concentration of solids, etc., so there is no particular limitation, but increasing the thickness to a certain value or more will increase the transparency. It is possible to reduce the possibility of cracking of the composite membrane by lowering the wettability and setting the film thickness to an appropriate upper limit or less. is more preferable, and 0.5 μm or more and 100 μm or less is particularly preferable. There are various methods for checking the film thickness, but if the substrate or coating film is transparent, an optical non-contact film thickness measuring device can be used. When the base material is opaque, the film thickness can be confirmed by scraping the coating film and checking the difference in level with the base material with a laser microscope.

In addition, the Si content in the composite film is preferably 0.1% by weight or more, more preferably 1% by weight or more, further preferably 5% by weight or more in terms of _SiO2 , It is preferably less than 100% by weight, more preferably 95% by weight or less, even more preferably 90% by weight or less. Within this range, the coating is less likely to crack and a lower moisture permeability can be obtained.

<About moisture permeability>
The moisture permeability of the obtained composite film or laminate can be determined by the method defined in JIS Z 0208, and the temperature and humidity conditions can be set at 25° C. and 90% RH.

The composite membrane preferably has a moisture permeability of 30 g/m ² ·day or less at 25°C and 90% RH, more preferably 25 g/m ² ·day or less, particularly preferably 20 g/m ² ·day or less, most preferably It is 10 g/m ² ·day or less.

EXAMPLES The present invention will be described in detail below using examples, but the present invention is not limited to the examples as long as the gist thereof is not exceeded.

[Example 1]
<Preparation of silicate hydrolyzate>
15.4 g of silicate MS-51 (Mitsubishi Chemical Co., Ltd.), 31.2 g of methanol, 3.25 g of pure, and 0.16 g of maleic acid were added, stirred for 1 hour, and then allowed to stand overnight to give a solid content concentration of 20 in terms of SiO ₂ . ~22% silicate hydrolyzate was obtained. As a result of measuring the average particle size of silica in this hydrolyzate using the method of Japanese Patent No. 3760471, the particle size was 2 nm.
<Preparation of PVA aqueous solution>
5.0 g of polyvinyl alcohol NL-05 (average degree of polymerization: 500, degree of saponification: 98.5 mol % or more) was added to 95.0 g of pure water. After stirring at room temperature for 15 minutes, the temperature was raised to 90° C. and the mixture was stirred for 1 hour to dissolve PVA and obtain an aqueous PVA solution having a solid concentration of 5%.

<Preparation of composite liquid>
6.0 g of silicate hydrolyzate was mixed with 16.0 g of PVA aqueous solution and stirred for 1 hour. The ratio of SiO ₂ solid content concentration and PVA solid content concentration was set to 60 mass %/40 mass %.
<Creation of laminate>
The resulting composite liquid was applied to a plastic film (substrate). A polybutylene succinate film (Bio-PBS, manufactured by Mitsubishi Chemical Corporation) was used as the substrate. After applying the composite liquid to the substrate using a non-wire bar coater (No. 18), it was dried at 80 ° C. for 1 hour with a constant temperature low temperature blower (DKN-402, manufactured by Yamato Scientific Co., Ltd.), and further at 105 ° C. for 16 hours. dried. The thickness of the resulting film was measured using a laser microscope (Keyence Corporation) and found to be 5 μm.

[Comparative Example 1]
<Preparation of composite liquid>
16.0 g of PVA aqueous solution was mixed with 6.0 g of aqueous colloidal silica solution having an average silica particle size of 16.7 nm (PL-2L, manufactured by Fuso Chemical Industry Co., Ltd., solid content: 20% by weight). The ratio of SiO ₂ solid content concentration and PVA solid content concentration was set to 60 mass %/40 mass %.
<Creation of laminate>
The resulting composite liquid was applied to a plastic film (substrate). A polybutylene succinate film (Bio-PBS, manufactured by Mitsubishi Chemical Corporation) was used as the substrate. After coating the substrate with the coating liquid using a non-wire bar coater (No. 18), a constant temperature low temperature blower (
After drying at 80° C. for 1 hour with DKN-402 manufactured by Yamato Scientific Co., Ltd., it was further dried at 105° C. for 16 hours. The thickness of the resulting film was measured using a laser microscope (Keyence Corporation) and found to be 5 μm.

[Comparative Example 2]
<Preparation of composite liquid>
6.0 g of colloidal silica aqueous solution (manufactured by Nissan Chemical Industries, Ltd., solid content 20% by weight) having an average silica particle size of 60 nm was mixed with 16.0 g of PVA aqueous solution. The ratio of SiO ₂ solid content concentration and PVA solid content concentration was set to 60 mass %/40 mass %.
<Creation of laminate>
The resulting composite liquid was applied to a plastic film (substrate). A polybutylene succinate film (Bio-PBS, manufactured by Mitsubishi Chemical Corporation) was used as the substrate. After coating the base material with the coating liquid using a non-wire bar coater (No. 18), it was dried at 80 ° C. for 1 hour with a constant temperature low temperature blower (manufactured by Yamato Scientific Co., Ltd., DKN-402), and then further at 105 ° C. 16. Time drying was performed. The thickness of the resulting film was measured using a laser microscope (Keyence Corporation) and found to be 5 μm.

<Moisture permeability measurement>
A moisture-permeable cup (No. 308) manufactured by Yasuda Seiki Co., Ltd. was used and produced according to JIS Z 0208. After measuring the weight of the produced moisture-permeable cup, it was placed in an environmental tester (manufactured by Espec Co., Ltd.) set at 25° C. and 90% RH, and tested according to JIS Z 0208.
<FT-IR measurement>
Measurement was performed using an FT-IR device (iN10MX, manufactured by Thermo Fisher Scientific). The company's software OMNIC (Version 8.3.103) was used for measurement and analysis. Measurement conditions and analysis conditions are as follows.
Measurement method) ATR method Shape of measurement sample) Coated urea prism) Diamond prism Accumulated number of times) 64 times Resolution) 4 cm-1
Background correction) Phase correction before sample measurement) Mertz method Spectral intensity) Absorbance Baseline correction) Auto baseline correction Smoothing) Auto smoothing Peak detection: Distribution function) Voigt function Peak detection: Peak detection Sensitivity) Low sensitivity peak detection: Half width ) 3.857-10
Peak fitting: noise) 5
Peak fitting: Baseline correction) Primary (linear) interpolation Peak fitting: Repeated calculation) Calculated until the standard deviation value is 1.0 or less The obtained coated substrates of Example 1 and Comparative Examples 1 and 2 were Analysis was carried out according to the above moisture permeability test, FT-IR, and solution 1H NMR measurements. Table 1 shows the results.

ここで、Ｌは膜と基板の総膜厚、Ｌ１は複合膜の膜厚、Ｌ２は基板の膜厚である。また、Ｐは全体の湿気透過係数（透湿試験から得られた数値）、Ｐ１は複合膜の湿気透過係数、Ｐ２は基板の湿気透過係数である。 After calculating the water vapor transmission rate according to JIS Z 0208, the water vapor transmission rate of the membrane alone was calculated using the following formula (1).

Here, L is the total film thickness of the film and the substrate, L1 is the film thickness of the composite film, and L2 is the film thickness of the substrate. Also, P is the overall moisture permeability coefficient (value obtained from the moisture permeability test), P1 is the moisture permeability coefficient of the composite membrane, and P2 is the moisture permeability coefficient of the substrate.

As a reference, a moisture permeable cup made of only a polybutylene succinate film (thickness: 30 μm, Bio ^- PBS, Mitsubishi Chemical) was prepared and subjected to a moisture permeability test. rice field. Using this value as a reference, the moisture permeability of the composite membrane (not the laminate) of Example 1 was calculated to be 11 g/m ² ·day. In Comparative Examples 1 and 2, when the particle size of silica was large, it was found that sufficient Si—O—C bonds were not obtained, and the moisture permeability was not sufficiently lowered. seems to have occurred.

Claims (10)

A composite film containing a resin having an OH group and a hydrolytic polycondensate of an alkoxysilane and/or a condensate thereof. A composite film containing a resin having an OH group and silica particles having a particle size of 15 nm or less. 3. The composite membrane according to claim 1 or 2, wherein the OH groups are alcoholic hydroxyl groups or carboxyl groups. 2. The composite membrane according to claim 1, wherein the hydrolytic condensate of alkoxysilane and/or its condensate is silica particles, and the average particle size thereof is 15 nm or less. 5. The composite membrane according to any one of claims 1 to 4, wherein the moisture permeability at 25°C and 90% RH is 20 g/ ^m2 ·day or less. A laminate obtained by laminating the composite film according to any one of claims 1 to 5 on a substrate. The laminate according to claim 6, wherein the moisture permeability at 25°C and 90% RH is 20 g/ ^m2 ·day or less. The substrate is selected from the group consisting of polyethylene terephthalate, polycarbonate, polylactic acid, polybutylene succinate, acrylic resin, PVA, paper, nonwoven fabric, polyethersulfone, polypropylene, polyethylene, polyimide, and cellulose triacetate. Item 8. The laminate according to Item 6 or 7. A step of mixing a solution containing an alkoxysilane and/or a hydrolytic polycondensate of its condensate with a resin having an OH group to form a composite solution;
A step of applying the obtained composite liquid to a substrate;
and a drying step of drying the base material to which the composite liquid has been applied. The method for producing a laminate according to claim 9, wherein the drying step is performed at 90°C or higher.