JPH10244617A - Thin film with gas barrier properties - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the remarkable enhancement of gas barrier properties even when the thickness of a thin film is further reduced by specifying the average particulate diameter of a particle making up the thin film of an inorganic oxide to be formed at least, on one of the faces of a plastic film and the degree of flatness of the particle. SOLUTION: This thin film with gas barrier properties comprises a film and a thin film of an inorganic oxide. The inorganic oxide forming a thin film layer is a silicon oxide or an aluminum oxide which has high oxygen gas barrier properties, vapor barrier properties and transparency, and is low- priced from an industrial point of view. Therefore, these oxides are particularly preferable. The average particulate diameter of the particle constituting the thin film should be 20nm or less, and the degree of flatness of the particle should be 0.10 or less. This degree of flatness is an indicator showing the high flattening degree of the particle, so that when the degree of flatness is 0.10 or less, the particle tends to be easily packed more densely into the thin film without a gap and the oxygen gas and vapor barrier properties are enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent thin film gas barrier film having excellent oxygen gas barrier properties and water vapor barrier properties formed by forming a thin film of an inorganic oxide on the surface of a base plastic film.

[0002]

2. Description of the Related Art Conventionally, a thin film gas barrier film comprising a plastic film as a base material and a thin film of an inorganic oxide such as aluminum oxide, magnesium oxide, or silicon oxide formed on the surface thereof has been used for forming various gases such as water vapor and oxygen. It is widely used for packaging of articles that need to be shut off and for preventing deterioration of foods, industrial supplies, pharmaceuticals, and the like.
In addition, thin film gas barrier films have recently been used for packaging, but also in recent years, liquid crystal display devices, solar cells, electromagnetic wave shielding,
Attention is also being paid to new uses such as a part of a transparent conductive sheet used for a touch panel, an EL substrate, a color filter, and the like.

[0003] Various thin film gas barrier films have been studied for improvement for the purpose of improving gas barrier properties, and for example, those in which the average roughness in the width direction of a liquid crystalline polyester film is specified (Japanese Patent Laid-Open Publication No. 3-
176123), a film in which the wetting tension and the surface roughness of one side of a biaxially stretched polypropylene film are defined (Japanese Patent Laid-Open No. 4-216829), and a film in which silicon oxide is mixed with the structure of a plastic film as a base material (Japanese Patent Laid-Open No. 4-
115940), a film in which the specific gravity and the average particle size of the vapor deposition raw material are specified (JP-A-6-57417, JP-A-7-342)
24) has been proposed. In order to improve the adhesion between the base film and the thin film mainly in the thin film gas barrier film, a resin film or an anchor coat is applied to the base film (JP-A-3-86539, JP-A-3-2318).
38, JP-A-3-278946, etc.).

[0004]

However, even with a film improved by the above method, it is necessary to obtain a film having an oxygen gas barrier property and a water vapor barrier property, which can be said to be sufficient for long-term storage at room temperature of foodstuffs and the like. Has a tendency to thicken the thin film portion, and as a result, problems such as crack generation of the thin film, reduced adhesion, transparency, reduced appearance, curl of the film, and the like, and also increased cost, Is still not enough. Further, even if the thickness of the thin film is increased, there is a limit in improving the oxygen gas barrier property and the water vapor barrier property, and a film having a higher gas barrier property with the same film thickness has been desired.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, the particles constituting the thin film portion of the thin film gas barrier film are more densely packed, thereby increasing the thickness of the thin film. The inventors have found that the gas barrier properties are significantly improved even if the thickness is reduced, and have reached the present invention. That is, the present invention relates to a thin film gas barrier film in which a thin film made of an inorganic oxide is formed on at least one surface of a plastic film, wherein the average particle diameter of the particles constituting the thin film is 20 n
m or less, and the flatness of the particles is 0.10 or less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
The raw material of the base film of the thin film gas barrier film of the present invention is not particularly limited as long as it is a plastic raw material used as a film. Specific examples include polyolefin (PO) resins such as homopolymers or copolymers such as ethylene, propylene, and butene; amorphous polyolefin resins (APO) such as cyclic polyolefins;
Polyester resins such as polyethylene terephthalate (PET), polyethylene-2,6-naphthalate and (PEN); polyamide (PA) resins such as nylon 6, nylon 12, and copolymerized nylon; polyvinyl alcohol (PVA) resins; Polyvinyl alcohol-based resin such as vinyl alcohol copolymer (EVOH), polyimide (PI) resin, polyetherimide (PEI) resin, polysulfone (PS) resin, polyethersulfone (PES) resin, polyetheretherketone (PEE)
K) Resin, polycarbonate (PC) resin, polyvinyl butyral (PVB) resin, polyarylate (PAR)
Resin, ethylene-tetrafluoroethylene copolymer (ETF
E), ethylene trifluoride chloride (PFA), ethylene tetrafluoride-perfluoroalkyl vinyl ether copolymer (FEP), vinylidene fluoride (PVDF), vinyl fluoride (PVF), perfluoroethylene-perfluoropropylene- Perfluorovinyl ether terpolymer (E
A resin composition comprising a fluororesin such as PE), an acrylate compound having a radically reactive unsaturated compound, a resin composition comprising the acrylate compound and a mercapto compound having a thiol group, epoxy acrylate, urethane acrylate, polyester acrylate, poly Photocurable resins such as resin compositions in which oligomers such as ether acrylate are melted into polyfunctional acrylate monomers,
And mixtures thereof. Known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, a filler, and a coloring agent can be added to the above-mentioned plastic raw materials.

[0007] The film obtained from the above plastic raw material may be an unstretched film or a stretched film. Further, it may be laminated with another plastic film. Such a plastic film can be manufactured by a conventionally known general method. For example, a raw resin is melted by an extruder, extruded by an annular die or T die, and quenched to produce a substantially amorphous unoriented film.
Further, the stretched film is obtained by subjecting the unstretched film to a film flow (hereinafter, referred to as a film flow) by a conventionally known general method such as uniaxial stretching, tenter-type sequential biaxial stretching, tenter-type simultaneous biaxial stretching, or tubular simultaneous biaxial stretching. It can be produced by stretching in the direction of the vertical axis) or in the direction perpendicular to the flow direction of the film (horizontal axis). The stretching ratio can be appropriately selected depending on the plastic used as a raw material, but is preferably 2 to 10 times in each of the vertical and horizontal axes.

[0008] The thickness of the plastic film is selected in the range of usually 5 to 500 µm, preferably 10 to 200 µm, depending on the application such as mechanical strength, flexibility and transparency as a base material of the thin film gas barrier film. . Further, the width and length of the film are not particularly limited, and can be appropriately selected depending on the application. Further, the film, corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment, surface treatment, surface treatment by a conventionally known method such as chemical treatment,
An anchor coat treatment or the like can be performed to improve the adhesion between the thin film and the film. Such a treatment can be performed during the production of the film or by a secondary processing after the production.

According to the anchor coating treatment, it is possible to improve the adhesion between the thin film and the film, but as a result, it can be said that good gas barrier properties are easily developed. The thickness of the anchor coat layer is 0.005 to 5 μm according to the surface irregularities of the film to be used.
It is preferred to be within the range of m. If it is less than 0.005 μm, coating unevenness is likely to occur, while if it exceeds 5 μm, the adhesiveness between the base film and the anchor coat layer tends to deteriorate, which is not so preferable. As the anchor coating agent, a polyester resin, an isocyanate resin, a urethane resin, an acrylic resin, an ethylene vinyl alcohol resin, a vinyl modified resin, an epoxy resin, a modified styrene resin, a modified silicon resin, an alkyl titanate, or a mixture of two or more of them. They can be used together. Further, conventionally known additives can be added to these.

On the other hand, the inorganic oxide forming the thin film layer of the thin film gas barrier film of the present invention is an oxide of a metal, a nonmetal or a submetal, and specific examples thereof include aluminum oxide, zinc oxide, antimony oxide, Indium oxide, calcium oxide, cadmium oxide, silver oxide, gold oxide, chromium oxide, silicon oxide, cobalt oxide, zirconium oxide,
Tin oxide, titanium oxide, iron oxide, copper oxide, nickel oxide, platinum oxide, palladium oxide, bismuth oxide, magnesium oxide, manganese oxide, molybdenum oxide, vanadium oxide, barium oxide, and the like.
Aluminum oxide is particularly preferred because it has high oxygen gas barrier properties, high water vapor barrier properties and transparency, and is industrially inexpensive. Such silicon oxide and aluminum oxide may be used alone or as a mixture. In addition, a small amount of metal,
Non-metals, sub-metals or hydroxides thereof, and carbon or fluorine may be appropriately contained in order to improve flexibility.

The thin film gas barrier film of the present invention comprises the above film and a thin film of an inorganic oxide.
It is necessary that the average particle diameter of the particles constituting the thin film is 20 nm or less. When the particle size is 20 nm or less, the oxygen gas barrier property and the water vapor barrier property are improved. The reason is that the particles are filled at a high density in the thin film, and the surface unevenness of the base film can be efficiently covered without gaps. It is estimated that The particle size of the particles of the thin film in the present invention means the particle size of the average particles forming the thin film, the lower limit is not particularly limited, but the smaller the average particle size, the more desirable, preferably 15 nm or less And particularly preferably 10 nm or less. Here, the average particle size of the particles constituting the thin film means the average particle size of each particle of the inorganic oxide constituting the thin film formed on the substrate film, and the inorganic particles before the vapor deposition. It does not mean the average particle size.

An important requirement for defining the thin film gas barrier film of the present invention is that the particle flatness is 0.10 or less, preferably 0.08 or less.
Such a flattening ratio is an index indicating that the degree of flattening of the particles is large, and when the flattening ratio is smaller than 0.10 or less,
Because the particles in the thin film are more likely to be densely packed without gaps,
It is presumed that they exhibit higher oxygen gas barrier properties and water vapor barrier properties.

The average particle size and flatness of the particles constituting the thin film defined by the thin film gas barrier film of the present invention are analyzed by analyzing an AFM unevenness image measured by an atomic force microscope (hereinafter, referred to as "AFM"). Can be obtained by As AFM, Digital Inst
instruments, Seiko Electronic Industries, Topome
A device commercially available from trix or the like can be used as it is. In this case, Q. Zong, D .; Inn
is, K .; Kjoller and V.S. B. Elin
gs, Surf. Sci. Letter, (199
3) Vol. 290, pages 688 to 692, a measurement mode corresponding to the resonance mode described is employed. For example, when a device NanoScope (c) manufactured by Digital Instruments is used, a tapping mode is used, and an SPI370 manufactured by Seiko Denshi Kogyo is used.
When 0 is used, the measurement should be performed in the dynamic force mode.

The flatness of the particles on the surface of the thin film is determined, for example, by using the SPI3700 manufactured by Seiko Denshi Kogyo to smooth the large irregularities and undulations derived from the plastic film of the substrate in the AFM irregularity image measured thereby. As processing, 3 software using the software attached to the AFM device
The following automatic inclination correction processing is performed, and then, for one to several particles arbitrarily selected, line analysis is performed using software attached to the apparatus, and from the cross-sectional data of the particles, the bottom radius r of the particles and the height of the particles are obtained. Find z and calculate z / r. In the present application, the average value of z / r for 100 particles analyzed in the same manner is defined as the flatness of the particles of the thin film gas barrier film. In addition, the average value of the bottom radius r of 100 particles analyzed above was defined as the average particle size of the particles constituting the thin film.

In the line analysis described above, when selecting arbitrary particles, particles that appear abnormally large or small are omitted, and the diameters of the selected particles are passed through, that is, the apexes of the particles and the ends of the particles are set. Set the line segment to be analyzed so as to include it. Hereinafter, with reference to the drawings, FIG. 1 is an enlarged schematic diagram of particles on an xy screen when performing line analysis, and FIG. 2 is a cross-sectional view of a line segment of line analysis. Measurement points, respectively _{(x i, y i, z} i) has a value, the vertices of the particles B in FIG. _{1 (x 2, y 2,} z 2) and a point at the end of the particle A
(X ₁ , y ₁ , z ₁ ) and C (x ₃ , y ₃ , z ₃ ),
The line segment of the particle to be analyzed must provide a cross-sectional image satisfying the following equations (1) and (2). However, if the swell exists at the base of the selected line segment, a display in which data equal to or less than the swell cutoff value (λc) is dropped may be used.

[0016]

[Number 1] _{| z 1 -z 3 | ≦ 0.05z} 2 ··· (1)

## EQU2 ## 0.9r ₂ ≦ r ₁ ≦ 1.1r ₂ (2)

Here, the bottom radius r of the particles on the surface of the thin film and the height z of the particles are selected from the two points A and B or C and B and analyzed. Here, the description will be made using the points A and B. The bottom radius r of the particles on the surface of the thin film is the distance between the points A and B, and the value (n) represented by the following equation (3)
m). The height z of the particles on the surface of the thin film is a height difference between two points A and B or C and B, and is a value (nm) represented by the following equation (4).

[0018]

R = [(x ₁ −x ₂ ) ² + (y ₁ −y ₂ ) ² ] ^1/2 (3)

(4) z = | z ₁ −z ₂ | (4)

Although the thickness of the thin film of the thin film gas barrier film of the present invention is not particularly limited and varies depending on the kind of the inorganic oxide, etc., considering the oxygen gas barrier property and the water vapor barrier property, and further considering the economic efficiency, The thickness of the thin film is 5-50
nm is preferred. In order to obtain more advanced oxygen gas barrier properties and water vapor barrier properties, the thickness of the thin film may be increased. However, if the thickness of the thin film is less than 5 nm, there is a possibility that the thin film becomes island-shaped and a portion where the thin film is not formed may occur. This is not preferable because there is a tendency that a uniform film cannot be obtained. It is generally desired that the thin film gas barrier film used for the packaging material has high transparency. In this case, the film is required to have a total light transmittance of usually 85% or more, preferably 90% or more. However, the thin film gas barrier film of the present invention has a thickness of the thin film within the above range of 5 to 50 nm. Such criteria can be easily satisfied.

In the thin film gas barrier film of the present invention, as a method of forming a thin film on a base plastic film, the thin film of the obtained thin film gas barrier film has an average particle diameter of 20 nm or less, and The conditions of the known vapor deposition method may be optimized so that the flatness of the particles is 0.08 or less. Specific examples of the deposition method include a resistance heating method, a high-frequency induction heating method, a vacuum deposition method using an electron beam irradiation heating method or a laser heating method, an ion plating method, a sputtering method, and a CVD method. In addition, as a deposition material for forming a thin film,
Simple metals or inorganic oxides or mixtures thereof can be used,
In the case of a simple metal, the formed thin film becomes an inorganic oxide by introducing oxygen gas.

[0021]

EXAMPLES Hereinafter, the contents and effects of the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. In addition, the method of the measurement and evaluation of the film in the following Examples is as follows. <Flatness of particles on thin film surface> Atomic force microscope (AFM)
As the SPI3700 manufactured by Seiko Denshi Kogyo,
In the dynamic force mode, the thin film surface of the thin film gas barrier film obtained in Examples and Comparative Examples was 1 μm × 1
AF where the area of μm was measured in 512 divisions in both the x and y directions.
After performing the tertiary tilt automatic correction process on the M unevenness image, select an arbitrary particle, perform line analysis, and analyze the particle height z and particle radius r from the cross-sectional image of the particle on the thin film surface. , Z / r were determined. And z / r for 100 particles
Was defined as the value of the flatness of the particles constituting the thin film gas barrier film. At this time, the cantilever used for the measurement had no wear or dirt. In addition, the location to be measured was a location without protrusions of several tens nm in height and dents of several tens nm in depth due to lubricants, fillers and the like in the film.

<Average Particle Size of Particles Constituting Thin Film> The average value of r of 100 particles measured during the line analysis of the flatness of the particles on the surface of the thin film was obtained. <Thin Film Thickness> The cross section of the thin film gas barrier film obtained in each of Examples and Comparative Examples was observed with a transmission electron microscope (H-600, manufactured by Hitachi, Ltd.), and the thickness of the thin film was measured. <Oxygen permeability> According to ASTM D-3985, an oxygen permeability measuring device (OX-TR, manufactured by Modern Control Co., Ltd.)
The measurement was performed under the conditions of a temperature of 25 ° C. and a relative humidity of 95% using AN100).

<Water vapor transmission rate> A water vapor transmission rate measuring apparatus (Permatran-W manufactured by Modern Control Co., Ltd.)
Using 1), the measurement was performed under the conditions of a temperature of 40 ° C. and a relative humidity of 90%. <Transparency> The total light transmittance was measured with a photometer (NDH-300A manufactured by NIPPON DENSHOKU).

Example 1 Biaxially stretched polyethylene terephthalate film (H-500, manufactured by Diafoil Hoechst Co., Ltd., thickness 12 μm)
Is mixed with an isocyanate compound (Coronate L manufactured by Nippon Polyurethane Industry Co., Ltd.) and a saturated polyester (Byron 300 manufactured by Toyobo Co., Ltd.), and coated with an average coating layer thickness of about 0.1 μm. And an anchor coat. On the coating surface of this film, a winding type vacuum evaporation apparatus was used, and SiO (manufactured by Sumitomo Citix Co., Ltd.) was used as an evaporation material using a high frequency induction heating source (maximum output: 5.04 KVA manufactured by Nippon Vacuum Engineering Co., Ltd.) , Evaporated at a heating output of 55%, pressure 2 × 10 ⁻⁵ Torr, distance between depositions 300 m
Under the conditions of m, a thin film gas barrier film on which a silicon oxide thin film having a thickness of 20 nm was formed was obtained. Table 1 shows the physical property results of the obtained thin film gas barrier film.

Example 2 A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner as in Example 1 except that the heating output was changed to 80%. Table 1 shows the physical property results of the obtained thin film gas barrier film. Example 3 A thin-film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner as in Example 1, except that the distance between vapor depositions was changed to 450 mm. Table 1 shows the physical property results of the obtained thin film gas barrier film. Example 4 In Example 1, oxygen gas was introduced to reduce the pressure to 1 × 10 ^−4.
A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner except that Torr was used. Table 1 shows the physical property results of the obtained thin film gas barrier film.

Example 5 A thin film gas barrier film on which a silicon oxide thin film was formed in the same manner as in Example 1 except that evaporation was performed at a crucible temperature of 1350 ° C. in place of heating by a resistance heating method. Obtained. Table 1 shows the physical property results of the obtained thin film gas barrier film. Example 6 In Example 1, the anchor coating agent was changed to 92 mol% of terephthalic acid as a dicarboxylic acid component, 8 mol% of sodium sulfoisophthalic acid, 75 mol% of ethylene glycol as a glycol component, and 25 mol% of diethylene glycol.
A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner except that an aqueous coating agent comprising 100 parts of water dispersible and 1900 parts of water was used. Table 1 shows the physical property results of the obtained thin film gas barrier film.

Comparative Example 1 A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner as in Example 1 except that the heating output was changed to 30%. Table 1 shows the physical property results of the obtained thin film gas barrier film. Comparative Example 2 A thin-film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner as in Example 1, except that the distance between vapor depositions was changed to 250 mm. Table 1 shows the physical property results of the obtained thin film gas barrier film. Comparative Example 3 In Example 1, oxygen gas was introduced and the pressure was increased to 7 × 10 ^−4.
A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner except that Torr was used. Table 1 shows the physical property results of the obtained thin film gas barrier film.

[0028]

[Table 1] Note) In Table -1, the unit of the oxygen permeability ^{(cc / m 2 · 24hr ·} atm), the unit of water vapor transmission rate is ^{(g / m 2 · 24hr ·} atm).

Example 7 In Example 1, the deposition material was Al (Mitsubishi Chemical Corporation).
A thin film gas barrier film on which an aluminum oxide thin film was formed was obtained in the same manner except that the heating was changed to an electron beam method, oxygen gas was introduced, and the pressure was changed to 2 × 10 ⁻⁴ Torr. The average particle diameter of the particles constituting the thin film of the obtained thin film gas barrier film is 7.5 nm, the flatness of the particles is 0.065, and the oxygen permeability is 0.3 cc / m ² · 24 hr ·
Atm, water vapor transmission rate was 3.5 g / m ² · 24 hr · atm, and total light transmission rate was 90%.

Example 8 In Example 1, the plastic film as the base material was changed to a polyether sulfone (PES) film (Sumitomo Bakelite, Sumilite FS, thickness 50 μm),
A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner except that a 0 nm thin film was formed. The average particle diameter of the particles constituting the thin film of the obtained thin film gas barrier film is 11.8 nm, the flatness of the particles is 0.075, the oxygen permeability is 0.2 cc / m ² · 24 hr · atm,
The water vapor transmittance was 0.3 g / m ² · 24 hr · atm, and the total light transmittance was 88%.

Example 9 In Example 1, the plastic film as the substrate was changed to a polyvinyl fluoride (PVF) film (Tedlar 100BG30UT manufactured by DuPont Japan, thickness 25 μm).
A thin film gas barrier film having a silicon oxide thin film formed thereon was obtained in the same manner except that a thin film having a thickness of 50 nm was formed. The average particle diameter of the particles constituting the thin film of the obtained thin film gas barrier film is 12.2 nm, the flatness of the particles is 0.055, and the oxygen permeability is 0.1 cc / m ² · 24 hr · atm.
The water vapor transmission rate was 0.1 g / m ² · 24 hr · atm, and the total light transmission rate was 89%. With respect to the obtained thin film gas barrier film, the flatness, oxygen permeability, water vapor permeability and transparency of the particles on the surface of the thin film were measured and evaluated by the method described above.

[0032]

The thin film gas barrier film of the present invention is
It has excellent gas barrier properties against water vapor and oxygen, and can be processed and used in various forms as containers and packaging for sealing foods, pharmaceuticals, medicines, fragrances, etc. whose contents do not like deterioration due to moisture or oxygen. . Further, the thin film gas barrier film of the present invention can be used by laminating it with other plastic films or paper, or can be used by attaching a cured film layer on a thin film. It can also be applied to conductive sheets and the like.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic view of particles on an xy screen when a particle constituting a thin film of a thin film gas barrier film is subjected to line analysis.

FIG. 2 is a cross-sectional view of a line segment used for line analysis of particles constituting a thin film of a thin film gas barrier film.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C08J 7/04 CFD C08J 7/04 CFDJ 7/06 CFD 7/06 CFDZ C23C 14/08 C23C 14/08 A 14/10 14 / 10 14/20 14/20 A

Claims (6)

[Claims] 1. A thin film gas barrier film having a thin film made of an inorganic oxide formed on at least one surface of a plastic film, wherein the particles constituting the thin film have an average particle diameter of 20 nm or less, and the flatness of the particles is 0 or less. .10
A thin film gas barrier film characterized by the following. 2. The thin film gas barrier film according to claim 1, wherein the flatness of the particles is 0.08 or less. 3. The thin film gas barrier film according to claim 1, wherein the plastic film is a polyester film. 4. The thin film gas barrier film according to claim 1, wherein the thin film has a thickness of 10 to 50 nm. 5. The thin film gas barrier film according to claim 1, wherein the total light transmittance is 85% or more. 6. The thin film gas barrier film according to claim 1, wherein a thin film made of an inorganic oxide is formed on the surface of the plastic film subjected to the anchor coating.