JPH01269530A - Composite film with transparency - Google Patents

Abstract

PURPOSE:To minimize the curl of an obtained vacuum-deposited film and also keep the balance of moisture resistance and oxygen barrier properties, by providing a thin film of tin oxide on the base material surface consisting of polymer film. CONSTITUTION:A base material is the non-stretched or stretched film obtained from a plurality of resin such as polyethylene terephthalate and polyethylene naphthalate having transparency and heat resistance. Then, on the upper surface of said base material the thin film of tin oxide is formed 300-3000Angstrom thick by means of vacuum deposition or ionic plating, etc. In such a manner, a composite film in which oxygen barrier and water vapor barrier properties are in balance and which is excellent in workability during additional processing and free from curl.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a transparent composite film in which a thin metal oxide film is provided on a base material made of a polymer film. The present invention relates to a composite film having balanced transparency.

<Prior art> In the field of pharmaceutical and food packaging, materials used for packaging are required to have various physical properties in order to enhance the protection of contents.
These required physical properties are becoming increasingly desirable.

Oxygen barrier properties and water vapor barrier properties are indispensable for packaging materials, especially from the viewpoint of protecting the contents from deterioration and oxidation. - Boat fishing is becoming more popular, and packaging materials are being designed from this perspective.

In general, from the perspective of oxygen barrier properties, ethylene vinyl alcohol copolymer, formalized polyvinyl alcohol (vinylon), biaxially oriented polyamide (ONy
), unstretched polyamide (CNy), cellophane, etc. are excellent.

In addition, from the perspective of water vapor barrier properties, biaxially oriented polypropylene (OPP), unoriented polypropylene (OPP)
) etc. are excellent.

On the other hand, films with both oxygen and water vapor barrier properties are made of polyvinylidene resin, polyvinylidene-polyacrylic acid copolymer resin, etc., and are inferior to coated foils.Although each of the above materials has its own merits, Since a single material cannot have all the physical properties, it is used as a laminate with multiple functions by laminating two or more different materials.

Aluminum foil has extremely good water vapor and oxygen barrier properties, and has a display effect in terms of gloss, but
Below μ, from the point of view of pinhole resistance and cost, films in which aluminum, etc. is vacuum-deposited on substrates such as PHT, ONy, and 0PPCPP have been recently used for moisture-proofing, oxygen barrier properties, light-shielding properties, and fragrance-retaining properties. It is actively used for display effects.

However, when such a metal M-coated film is used as a packaging material, the contents cannot be confirmed, and it cannot be heated in a microwave oven. Adhesion between the material and the deposited layer was insufficient.

In addition, a vapor-deposited film has been devised in which 1 m of silicon oxide, magnesium oxide, or aluminum oxide is provided on a polymer film instead of the AI vapor-deposited layer to provide transparency, moisture resistance, and oxygen barrier properties. (Tokuko Showa 53-1
2953 Publication, JP-A-61-51332, JP-A-Sho 6
2-179935) However, although the vapor-deposited thin films of silicon oxide, magnesium oxide, aluminum oxide, etc. described above can provide moisture-proofing and oxygen barrier properties, the vapor-deposited film of magnesium oxide gradually loses air over time. CO inside! It reacts with magnesium carbonate, resulting in loss of water resistance and deterioration of both 08 and HmO barrier properties.

On the other hand, aluminum oxide vapor-deposited films have insufficient H,O barrier properties, and silicon oxide vapor-deposited films have
Since a glass-like thin film with extremely different linear expansion coefficients is provided on a plastic film, the thermal stress strain that occurs between the base material made of plastic film and the thin film interface during thin film formation results in a vapor-deposited film that has a very different linear expansion coefficient. If the adhesion is insufficient and the film is deposited on a substrate with a diameter of about 6 to 100 μm, the resulting vapor-deposited film will curl severely, making it difficult to laminate it with other substrates or print text or pictures on the vapor-deposited surface. There were major problems such as extremely poor workability during post-processing.

<Problems to be Solved by the Invention> The present invention solves the above-mentioned conventional drawbacks, and its purpose is to provide a new M-deposited film on a base material, thereby improving the resultant vapor-deposited film. The present invention provides a composite film that has extremely low amounts of , l'J -, and has transparency with well-balanced moisture proofing and oxygen barrier properties.

<Means for Solving the Problems> The present invention achieves the object by providing a tin oxide thin film layer on at least one side of a substrate made of a polymer film by a PVD method such as vacuum evaporation or sputtering ion blating in a vacuum system. can be achieved.

More specifically, the base plastic film used in the present invention is an unstretched film obtained from one or more resins such as polyethylene, polypropylene, polyamide, polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, etc., at any stretching ratio. , and may contain additives to provide surface smoothness and stability, but these may bleed to the surface under vacuum, reducing the adhesion between the substrate and the thin film. Films made of resins containing as little additives as possible are preferred, and particularly transparent and heat-resistant polyethylene terephthalate (CPET), polyethylene naphthalate (PEN), etc. are preferred.

The tin oxide thin film referred to in the present invention is produced by a general vacuum evaporation method using resistance heating, high-frequency molten metal heating, or electron beam heating method in a vacuum system, or by bipolar direct current sputtering (DC).
, magnetron sputtering such as radio frequency sputtering (RF), and ion blating, or, as an application of the above methods, reactive evaporation and sputtering, which form a thin film while introducing oxygen and an inert carrier containing oxygen into a vacuum system. The thin film may be obtained by any method such as , ion blating or the like.

Ion blasting and sputtering are superior in terms of adhesion to the substrate, but vapor deposition is the most economical because it can be processed in a roll at high speed. Furthermore, the physical properties of the resulting vapor-deposited film are also sufficiently satisfactory.

The tin oxide thin film in the present invention obtained by the above method includes So, SnO, SnJ, 5ntOs, 5nsO.
It is considered to be a mixed state of a, 5nvO+s ・nH=o, 5nOa, etc., and the content ratio of each is determined depending on the degree of vacuum in the vacuum system, water vapor partial pressure, residual oxygen partial pressure, substrate temperature, and reactive evaporation when producing a thin film. , differs depending on the oxygen partial pressure in the gas introduced during sputtering, etc.

However, the tin oxide thin film in the present invention refers to metal S
It is considered to be a mixed state with a large number of n and a composition consisting of 5nOx-x (x-0 to 2). The appropriate thickness of the tin oxide thin film is 300 Å to 3000 Å, and 30 Å to 3000 Å.
If it is less than 0 Å, a uniform thin film will not be formed on the substrate, resulting in insufficient oxygen and water vapor barrier properties.
When the temperature exceeds 0λ, a small coefficient of thermal expansion is formed on the base material (4
Since a tin oxide thin film with low thermal conductivity and low thermal conductivity is formed, temperature changes occur between the inside of the base material and the surface during thin film formation, resulting in thermal stress distortion at the interface. Cracks occur in the thin film, and similarly, the oxygen and water vapor barrier properties are sharply reduced, and more importantly, the transparency of the thin film, which is a feature of the present invention, is significantly reduced.

For this reason, the thickness of the tin oxide thin film is more preferably 500 Å to 1000 Å.

t, LBe, F, Na+Mg+A1.
Sl, P, CI, K.

T1. Cr+Mn+Pe, Co, Nl+Cu, Zn,
Even if it is contained as inorganic substances such as Bi and Pb, it is 10% by weight.
The following is acceptable as long as it does not affect the physical properties.
If it is contained in an amount of 10% by weight or more, the water resistance of the deposited film decreases, especially due to metal components with low ionization energy, resulting in a sudden decrease in barrier properties.

Furthermore, the vapor-deposited film of the present invention may be extrusion coated with a heat-sealable resin such as polyethylene, polyethylene, polypropylene, or the like, or a film made of the above resin may be laminated and composited with the vapor-deposited film to be used as a barrier packaging material. In particular, when used as a so-called retort packaging barrier material for sterilizing the contents of foods, etc., by the retort method, polyethylene terephthalate or biaxially oriented polypropylene with a printed layer of letters, designs, etc. on the outer layer of a vapor-deposited film is used. , at least one layer of biaxially stretched nylon or other material that can be used as an outer layer film is provided, and the outer layer film and the non-deposited side of the non-deposited film of the vapor-deposited film are laminated, and an olefin that can be used as a sealant is provided in the innermost layer. Composite films are preferred.

Under retort conditions, the packaging material receives considerable heat and stress due to heating and pressurization, causing at least some elongation of the outermost layer, and rapid cooling causes cracks at the interface between the base material and the vapor deposited layer as described above, causing the vapor deposition to occur. The adhesion of the layer becomes insufficient, and in the worst case, the deposited layer will peel off.

For this reason, it is desirable that the vapor deposition layer be provided as close as possible to the innermost olefin layer side and laminated.

Further, the means for forming the tin oxide thin film in the present invention may be any of the methods described above, but
In terms of high-speed productivity and economy, tin oxide is used as a vapor deposition material, and vacuum vapor deposition is performed using a heating means such as boat resistance heating, high-frequency induction, or electron beam, or tin is used as a vapor deposition material and a specific 0. Reactive vapor deposition with introduction of a gaseous carrier is preferred.

Sputtering, ion blating, etc. can be used to form a vapor deposited film on a base material, so these methods can be used when adhesion is important.

In addition, when forming a thin film layer on a base material, the base material does not require any specific treatment, but Ot+ N*+ Ar+ He, N
Discharge treatment under 10-3 to several Torr with gas such as E, so-called low-temperature plasma treatment, and ion bombardment treatment in which charged objects, flakes, etc. on the base material are sputtered with inert gas, and the surface is cleaned. In this way, a thin film layer with better adhesion to the base material is formed.

Furthermore, by providing a thermosetting resin layer on the base material, the adhesion between the base material and the thin film layer can be improved.

Function> The present invention provides an oxygen barrier and a water vapor barrier by providing a thin film layer of 300 Å to 3000 Å consisting of a tin oxide thin film layer on a substrate using a PVD method such as vapor deposition, sputtering, or ion blating in a vacuum system. A composite film with well-balanced properties, no curling, and excellent workability during post-processing was obtained.

<Example-1> Using a 12μ biaxially stretched polyester film (NS film manufactured by Kijin) as a base material, the following was performed on one side using a winding type vapor deposition sputtering device (SPlf-020 special model manufactured by Japan Vacuum Technology Co., Ltd.) using electron beam heating. Under these conditions, a vapor-deposited film with excellent transparency was obtained in which about 500 tin oxide I films were continuously provided.

(Vapor deposition conditions) Vapor deposition material Snow C manufactured by Kojundo Kagaku Kenkyusho 3N) Vacuum degree 1.5X 10-' (Torr) Vapor deposition speed 25-26 (person/S) (Crystal oscillation type) Temperature of the Kuechling roll at this time The film thickness was measured at 10°C using a stylus method (DectaKll, Japan Vacuum Technology Model) and found to be 500±20% in the width direction of the film.

When the oxygen barrier properties and water vapor barrier properties of the film obtained here were measured, they were each 3.1 (cc/
rrf, dan, ate) 1n25℃, 100%R
H, 3.0 (g/n1day), and the barrier properties were good. 700 to evaluate transparency.
When the transmittance of ~400n-wavelength was measured, it was 700~
Transparency of 80% or more was observed at 550 nm.

Next, when I checked the degree of curling, there was no curling at all, and it did not look like an untreated substrate at all.

Furthermore, a two-part curable urethane adhesive was applied to the vapor deposition surface of this vapor-deposited film, and a composite film was obtained by laminating it with 60 μm of unstretched polypropylene (Shi-Aroma AT, manufactured by Showa Denko) under the following conditions.

When the oxygen barrier and water vapor barrier were similarly measured, both were 1 or less. (Units are the same as above) (Processing conditions) ・Adhesive χ) ・Plate 135 tt -754! Grating ・Nip pressure 4k
g/ctr・Line speed 20-/in・Drying temperature 70 @-80”-80°C・Vitality
Unrolling 6-7kg/cm Oven 6
kg/cm Winding 5 kg/cm ・Impression pressure 3.5 kg/CI ・Heat roll temperature 75 ℃ <Example-2> Implemented except that the line speed was changed to make the deposited film thickness 100 ± 20% A composite film was obtained in the same manner as in Example-1.

<Example-3> Using the same apparatus as <Example-1>, (Ox/Ar)
Metal Sn (4
The beam power was adjusted so that the deposition speed was 40 people/S, and the test was carried out in the same manner as in Example-1.
A vapor deposited film was obtained.

When the obtained thin film layer was measured, it was found that there were 1200 people.

<Comparative Examples-1 to 3> SiO (manufactured by Osaka Titanium), Mg0 (manufactured by Kojundo Kagaku Kenkyusho, 99.9% or more), and AlzOs (manufactured by Kojundo Kagaku Kenkyusho, 99.9% or more) were deposited, respectively. The obtained vapor-deposited film was evaluated in the same manner.

<Example 4.5> Under the same conditions as Example-1, the film thickness was changed to 300 and 300, respectively.
A composite film of 1,000 ml was obtained.

The measurement results of the above Examples and Comparative Examples are shown in Table 1.

(Left below) Effect〉 300%
By providing a tin oxide thin film layer of ~3000 Å, the conventional S10. It has oxygen and hydrogen gas barrier properties equivalent to or better than MgO, AItoz vapor-deposited film, and it becomes a composite film with excellent transparency, and workability due to curling during secondary processing is extremely poor. A highly practical composite film having transparent barrier properties without this problem was obtained.

Patent applicant Toppan Printing Co., Ltd. Representative: Kazuo Suzuki

Claims (3)

[Claims] (1) On the surface of a base material made of a transparent polymer film,
A transparent composite film with a tin oxide thin film of 0 Å to 3000 Å. (2) The transparent composite film according to claim (1), further comprising a resin layer having heat-sealability provided on the tin oxide thin film side via an adhesive layer. (3) With an adhesive layer on the side opposite to the tin oxide thin film of the base material,
3. The composite film having transparency suitable for sterilization treatment according to claim 2, further comprising an outer layer film consisting of a polyethylene terephthalate film, a biaxially oriented polypropylene film, or a biaxially oriented nylon film.