JP3191321B2 - Plastic coating materials and coated plastic films - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating material used for coating an inorganic substance on a plastic film by a vapor phase thin film forming method such as vapor deposition , and a gas barrier produced by using the coating material. It relates to a plastic film having excellent properties. The coated plastic film has a gas barrier property, and is used as a film for packaging a retort food or the like by itself or in the form of a surface hard coat and a laminate.

[0002]

2. Description of the Related Art Conventionally, as such a plastic film, for example, a plastic film on which SiO is deposited is known. The structure of the film is obtained by depositing SiO on at least one side of a plastic film at about 1500 ° and hard coating and laminating the surface. However, the material of SiO is expensive, and thus such a plastic film has a problem that the production cost of the film is high.

[0003] Therefore, as economical, Si, Si
A plastic film deposited by a mixed material of O and SiO ₂ has been proposed. However, the plastic film is scattered during the manufacturing process,
An increase in the degree of vacuum, etc., has been observed, and as a result, an inorganic compound thin film having a dense structure has not been obtained.
There is a problem that the gas barrier property is inferior.

[0004]

SUMMARY OF THE INVENTION A first object of the present invention is to provide a coating material capable of forming an inorganic compound thin film having a dense structure despite being made of a mixed material of Si and Si oxide. Is to provide the material. A second object of the present invention is to produce economically, 1 cc / m ² . 2
4 hr. An object of the present invention is to provide a plastic film coated with an inorganic compound thin film having an extremely high gas barrier property of atm or less.

[0005]

According to the present invention, first, S
A material for coating a plastic film, comprising i, Si oxide and other inorganic compounds, and having a porous structure. The present invention secondly provides a coating of 1 cc / m ² . 2
4 hr. It is a plastic film having a gas barrier property of atm or less. Here, the gas barrier property is determined by ASTM
It is a value measured in accordance with -D1434-75 (the same applies hereinafter).

The coating material of the present invention contains Si and a Si oxide.
O, SiO ₂ and mixtures thereof. Preferably, SiO ₂ is used. The mixing ratio of Si and Si oxide is as follows. That is, based on 100 parts by weight of Si, the Si oxide is usually 20 to 400 parts by weight, preferably 50 to 300 parts by weight, and more preferably 100 to 2 parts by weight.
50 parts by weight.

When a mixture of SiO and SiO ₂ is used as the oxide of Si, the compounding ratio is as follows. That is, for 100 parts by weight of SiO ₂ , SiO ₂
Is usually 50 to 400 parts by weight, preferably 50 to 200 parts by weight, more preferably 100 to 150 parts by weight.

The inorganic compound used in the present invention other than Si and the oxide of Si is not particularly limited as long as it does not inhibit the gas barrier properties of the plastic film coated with the plastic coating material of the present invention. ,
Alkaline earth metals (Mg, Ca, Sr, Ba, etc.), aluminum group (Al, B, Ga, In, etc.), carbon group (S
n, Ge, etc.), titanium group (Ti, Zr, etc.), inorganic compounds containing them, oxides, borides, nitrides thereof, such as MgO, Al ₂ O ₃ , SnO, TiB ₂ , T
iO _2, B ₂ O _3, etc., and mixtures of the preceding.

The inorganic compound is usually 1 to 80 parts by weight, preferably 10 to 60 parts by weight, more preferably 30 to 5 parts by weight, based on 100 parts by weight of the total amount of Si and the oxide of Si.
0 parts by weight are blended.

The coating material of the present invention has a porous structure, and the ratio of porosity (porosity) in the porous structure is 5 to 60 in apparent specific gravity rather than the specific gravity of the material.
%, Preferably 10 to 40% smaller, more preferably 15 to 30% smaller.

The coating material of the present invention is produced, for example, as follows. That is, it is manufactured by molding, foaming, and further sintering a composition obtained by adding a substance showing a substantially basic property to a mixed powder of Si and Si oxide, and a powder obtained by mixing other inorganic compounds. You.

[0012] Here, as the substance having a substantially basic property, an oxide formed on the surface of Si, which is a component of the coating material of the present invention, can be removed, and hydrogen gas is used together with Si and the Si oxide. Is not particularly limited as long as the object of the present invention can be achieved.Examples include silicates such as sodium silicate, sodium orthosilicate and sodium metasilicate, and boric acids such as potassium tetraborate. And the like, alkali metal compounds, alkaline earth metal compounds and the like. As the substance showing substantially basic property, 5
% Aqueous solution having a pH of 8 to 14, preferably 12 to 14. The substance showing a substantially basic property is preferably compounded as a powder.

In the above-mentioned production method, molding is carried out by, for example, pressure molding, plastic molding (such as extrusion molding), casting, injection molding or the like. The molding is performed by a method known per se. In the method of molding the powdery composition once into a muddy or pasty form, the powdery composition is formed into a muddy or pastey form using an appropriate medium, for example, water or alcohol (methanol, ethanol, etc.). It is said.

At the time of molding, Si and Si oxides generate hydrogen gas together with a substance showing substantially basicity, and are foamed and molded by the generated hydrogen gas and heat.

The molded and foamed material composition is then subjected to a sintering step. By appropriately sintering, the powder compact is consolidated into a sintered body having a reduced porosity, that is, a porous structure having the appropriate porosity. The sintering conditions are, for example, 800 to 1500 ° C., preferably 1300 ° C.
C., about 20 minutes to 3 hours, preferably about 1 hour. The sintering is preferably performed in the atmosphere under an inert gas (particularly, argon) atmosphere.

As a film for a plastic film coated with the coating material of the present invention, a film conventionally used in this field may be used. Normal,
The film is obtained by dissolving or melt-extruding an organic polymer, and is stretched in the longitudinal direction and the width direction as necessary. Typical examples of the organic polymer include polyester, polyethylene, nylon 6, polyamide, and polyimide. The thickness of the coating layer made of an inorganic substance in the plastic film coated with the vapor deposition material of the present invention is generally 0.005 to 0.5 μm, preferably 0.01 to 0.3 μm, more preferably 0.02 to 0.3 μm.
0.1 μm.

The coated plastic film of the present invention is usually produced by applying the above coating material on the plastic film by a vapor phase thin film forming method. Vapor deposition methods (vacuum deposition, chemical vapor deposition, etc.)
And the like, and preferably a vacuum chamber (particularly, a high vacuum chamber).
Is exemplified.

The vacuum deposition method is a method in which a coating material in a crucible is heated and evaporated by resistance heating, induction heating, electron beam heating, or the like in a vacuum chamber to adhere an inorganic material to a plastic film as a substrate. . At this time, the heating temperature and the heating method differ depending on the material, purpose, and the like, and an appropriate material must be selected. In the present invention, preferably, an electron beam heating method is used, and the input power of the electron beam is usually 30 to 100 kW.

The chemical vapor deposition method is a method in which a reaction gas such as oxygen is introduced into a vacuum chamber to cause an oxidation reaction or the like. In the present invention, oxygen is usually used as a reaction gas, the degree of vacuum at the time of vapor deposition is set at 5 × 10 ⁻⁴ to 2 × 10 ⁻³ Torr, and an oxidation reaction is caused by vapor deposition using an electron beam vapor deposition method.

In this manner, a film made of Si, an oxide of Si, another inorganic compound, an alkali metal, an alkaline earth metal, or an oxide of a substance having a substantially basic property is formed on the plastic film. The plastic film having the coating formed thereon is formed into a packaging film for retort foods or the like by performing surface hard coating and lamination by a method known per se.

[0021]

【Example】

Example 1 Powders of Si, SiO ₂ and MgO were mixed at 24:36:40
Na ₂ SiO ₃ was added to 200 g of the powder material mixed at wt%.
A liquid 70 obtained by mixing (water glass) with 0.5 wt% of water.
After adding cc, the mixture was stirred to form a clay, molded into a cylindrical mold, molded, dried at 200 ° C. for 5 hours, and then 1300 ° C.
For 60 minutes to produce a deposition material. The produced deposition material had a porous structure having a specific gravity of 67% with respect to the specific gravity of the powder material composed of Si, SiO ₂ and MgO.

Example 2 Powders of Si, SiO ₂ and Al ₂ O ₃ were mixed at 28:42:
To 200 g of the powdered material mixed at 30 wt%, 75 cc of a liquid obtained by mixing 1.0 wt% of NaOH with water was added and stirred to form a clay, which was then molded into a cylindrical mold and molded.
After drying at 200 ° C. for 5 hours, the material was sintered at 1300 ° C. for 60 minutes to prepare a deposition material. The produced deposition material is
The porous structure had a specific gravity of 69% with respect to the specific gravity of the powder material composed of Si, SiO ₂ and Al ₂ O ₃ .

Example 3 To 200 g of a powder material in which Si and SiO ₂ powders were mixed at 47:53 wt%, NaOH was added to water in an amount of 0.5 w
70% of the liquid mixed with t% is added and stirred to form a clay,
It was put into a cylindrical mold, molded, dried at 200 ° C. for 5 hours, and then sintered at 1300 ° C. for 60 minutes to produce a deposition material. The produced vapor deposition material had a porous structure having an apparent specific gravity of 75% with respect to the specific gravity of the powder material.

Example 4 70 cc of a liquid prepared by mixing 0.36 wt% of Na ₂ SiO ₃ (water glass) with water was added to 200 g of a powder material in which Si and SiO ₂ powders were mixed at 47:53 wt%, followed by stirring. To a clay, molded into a cylindrical mold, dried at 200 ° C. for 5 hours, and then dried at 1300 ° C. for 60 hours.
After sintering for 5 minutes, a deposition material was manufactured. The produced vapor deposition material had a porous structure having an apparent specific gravity of 90% with respect to the specific gravity of the powder material.

Comparative Example 1 Ethyl silicate (Si (OC) was added to a powder material in which Si and SiO ₂ powders were mixed at a ratio of 40:60 wt%.
₂ H _{5) 4)} 1: For 200g in a mixing ratio of 1, a clay-like and stirred with absolute alcohol 100 cc, and molded by putting the mold in a cylindrical shaped die, 200 ° C.
For 5 hours, and then sintered at 1300 ° C. for 60 minutes to produce a deposition material. The fabricated deposition material was Si
And were almost dense structure having 99% of the apparent specific gravity relative to the specific gravity of the formed powder material in SiO _2.

EXPERIMENTAL EXAMPLE 1 The scattering of the material and the degree of vacuum during the vapor deposition of the plastic film using the materials manufactured in the examples and comparative examples were observed by electron beam evaporation. Table 1 shows the results. (Experimental Method) Using the materials manufactured in the respective Examples and Comparative Examples, a vapor deposition experiment was performed by the EB vapor deposition apparatus shown in FIG. Before performing the vapor deposition experiment, the inside of the vacuum chamber was evacuated to 6 × 10 ⁻⁴ pa or less. The input power of the electron beam is 35 kW,
The crucible and the EB gun were water-cooled with cooling water.

[0027]

[Table 1]

[0028]

According to the conventional fine powdered material of Si, SiO and SiO ₂ , the material is scattered due to the diffusion and charging of heat of the electron beam during the coating operation of the plastic film using the same. In addition, a gas is released from impurities adhering to and mixed with the material due to diffusion of heat, thereby increasing the degree of vacuum. On the other hand, the material for coating a plastic film of the present invention is a vapor deposition material having substantially no scattering of the material and no increase in the degree of vacuum.Therefore, a gas barrier film manufactured by a vapor deposition method using this material is: It has an inorganic coating with a dense structure, 1 cc / m ² . 24
hr. It has high barrier properties of atm or less.

[Brief description of the drawings]

FIG. 1 is a structural diagram of a vapor deposition apparatus of Examples 1, 2, and 3.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roll of PET film 2 Tensioner 3 Cooling drum 4 Shutter 5 Slit 6 Electron beam evaporation source 7 Take-up roll

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁷ Identification code FI C23C14 / 20 C23C14 / 20 (56) References JP-A-2-221366 (JP, A) JP-A-63-86860 (JP) U.S. Pat. No. 4,748,313 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 7/00-7/18 B32B 5/18, 7/02 B32B 9/00, 27 / 06 C23C 14/20

Claims (3)

(57) [Claims] 1. It contains Si, Si oxides and other inorganic compounds, and has an apparent density higher than the specific gravity of the inorganic components.
A plastic film coating material having a porous structure having a specific gravity of 5 to 60% smaller . 2. The plastic film coating according to claim 1, wherein a powdery composition containing Si, a Si oxide, another inorganic compound, and a substance having a substantially basic property is molded, foamed, and sintered. Materials. 3. A process according to claim 1 or 2 1 cc / m ² coated by using a coating material according to. 24h
r. A plastic film having a gas barrier property of atm or less.