JPS5938889B2 - Vapor deposited polyester film - Google Patents

Description

[Detailed description of the invention] This invention relates to vapor deposited polyester films.

Films made of polyester films such as polyethylene terephthalate with metals or metal oxides deposited on the surface have high tensile strength, impact strength, and tear strength, and extremely low permeability to gases such as oxygen and water vapor, so they can be used as insulation materials, It is widely used as a metal-based, gas-barrier packaging material, and is particularly suitable as a food preservation film.
However, traditional metal device polyester film
The adhesive strength between the film and the metal or metal oxide is insufficient, and there are various problems depending on the application. For example, when used as a heat insulating material for building materials, organic solvents such as toluene and methyl ethyl ketone in the adhesive used when installing the heat insulating material reduce the adhesive strength at the interface between the film and the deposited metal, resulting in peeling. This results in a decline in its performance as a building material. In addition, when used as a packaging material for food preservation, after the food is packaged, boiling water, steam, high-temperature heating,
When heat treatment such as high-temperature sterilization using dielectric heating or a microwave oven is applied, the interface between the film and the vapor-deposited metal peels off, making it impractical for food packaging that involves pole sterilization or retort sterilization. The present invention provides a vapor-deposited polyester film that solves the above-mentioned conventional problems.

That is, the present invention is a vapor-deposited polyester film characterized in that a metal, metal oxide, or silicon oxide is vapor-deposited on at least one side of a film made of a modified polyester containing a structural unit having a sulfonic acid metal salt as a side chain. The film made of a modified polyester containing a structural unit having a sulfonic acid metal salt as a side chain used in the present invention includes a known film described in Japanese Patent Publication No. 34-10497, and includes aliphatic, aromatic or aliphatic Contains a structural unit produced using an ester-forming monomer component such as a dibasic acid component, an oxycarboxylic acid component, or a glycol component with at least one sulfonic acid metal salt bonded to a ring carbon atom. This is a film molded from modified polyester.

The metal of the sulfonic acid metal salt is preferably an alkali metal or an alkaline earth metal, such as sodium, potassium, calcium, barium, and lithium, as well as lead and lanthanum.

Ester-forming dibasic acid components include terephthalic acid, isophthalic acid, 5-hydroxylisophthalic acid, 2
, 6-naphthalene dicarboxylic acid, adipic acid, azelaic acid, sebacic acid, dodecanedioic acid, and ester-forming derivatives of these acids.

It is preferable that 50 mol % or more of the dibasic acid component is terephthalic acid or 2,6-naphthalene dicarboxylic acid. Further, examples of the oxycarboxylic acid component include hydroxybenzoic acid. Examples of the ester-forming glycol component include ethylene glycol, propylene glycol, butanediol, diethylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, neopentyl glycol, and cyclohexanedimethanol.

the sulfonic acid metal salt of the dibasic acid component, oxycarboxylic acid component or glycol component; and an ester-forming dibasic acid component that does not have a sulfonic acid metal salt in its side chain;
A copolymerized polyester comprising a structural unit having a sulfonic acid metal salt as a side chain is obtained by condensation polymerization with an oxycarboxylic acid component or a glycol component in the presence of a catalyst by a conventional method.

The modified polyester used in this invention is a single copolyester consisting of a constitutional unit having the above-mentioned sulfonic acid metal salt as a side chain, or a copolyester consisting of this copolyester and a constitutional unit having no sulfonic acid metal salt in its side chain. It is a mixture with ordinary polyester. The amount of the sulfonic acid metal salt contained in the modified polyester is 0.5 to 50 mol%, preferably 1 to 20 mol%, based on the dibasic acid component contained in the modified polyester, and When the acid metal salt is less than 0.5 mol%, no improvement in the adhesive strength at the interface between the film and the vapor deposited layer is observed;
If it exceeds mol%, the physical properties of the film may deteriorate, which is not preferable.

The above modified polyester for forming the film includes:
If necessary, auxiliary agents such as antistatic agents, lubricants, antiblocking agents, antifogging agents, and surfactants may be added.

As the antistatic agent, sodium aromatic sulfonate is effective, and as the lubricant, thyroid,
Silica-based materials such as talc and kaolin, organic and inorganic calcium salts such as calcium terephthalate and calcium carbonate,
Lithium salts such as lithium acetate are effective. The film in the present invention includes an unstretched film that is formed into a sheet shape, and a stretched film that is uniaxially or biaxially stretched. It includes the formed film and a laminated film consisting of two or more layers of this modified polyester film and a normal polyester film. This laminated film consisting of two or more layers is produced by coextrusion, in-line lamination, extrusion lamination, dry lamination, etc. of the modified polyester containing the sulfonic acid metal salt and ordinary polyester. Ru. In the case of the above-mentioned dry lamination method, the normal polyester film is rolled, uniaxially stretched or biaxially stretched, and the modified polyester film may be unstretched, uniaxially stretched or biaxially stretched. The surface of the film obtained as described above on which vapor deposition is to be performed may be subjected to corona discharge treatment, flame treatment, physical treatment using plasma, etc., chemical treatment using acid, alkali, oxidizing agent, etc., isocyanate, ethyleneimine, alkyl titanate, etc. The activation of the film surface can be further improved by optionally carrying out an anchor coating treatment using an adhesive. The metal or metal oxide deposited on the surface of the film includes metals such as gold, silver, aluminum, zinc, and tin, and their oxides, and also includes silicon oxide.

Vapor deposition on the film surface can be performed by a conventional method. The vapor-deposited polyester film of the present invention has excellent organic solvent resistance, water resistance, hot water resistance, and heat resistance. It never decreases. Further, the film of the present invention has antistatic properties. Polyethylene, polypropylene, ionomer, ethylene,
Sheets or films of vinyl acetate copolymer, ethylene ethyl acrylate copolymer, polyester, polyamide, etc. can be laminated and used. Examples of the present invention will be described below. Example 1 A copolymerized polyester composed of an acid component of 6 mol% of sodium 5-sulfoisophthalate, 94 mol% of terephthalic acid, and an ethylene glycol component was melt-extruded into a sheet form from an extruder at a temperature of 295°C, and then cooled. and then 85
The film was stretched 3.5 times in the machine direction at 135°C, then 3.5 times in the transverse direction at 135°C, and further heat-set at 200°C to obtain a biaxially stretched polyester film.

One side of this polyester film was subjected to a corona discharge treatment, and then aluminum was vapor-deposited by a conventional method. This aluminum vapor-deposited film was immersed in boiling water for 3 minutes, then taken out, and 23W was applied to the vapor-deposited surface. When a test was repeated 10 times in which a cellophane tape of I width was crimped, one end of the cellophane tape was bent in a 180 degree direction, and the cellophane tape was rapidly peeled off. The area was 0 to 5% of the total area, and the vapor-deposited surface was hardly peeled off. For comparison, 5-
When the above peeling test was performed on the aluminum-deposited polyester film obtained in the same manner as in the above example using ordinary polyethylene terephthalate consisting of a terephthalic acid component and an ethylene glycol component without adding sodium sulfoisophthalate, it was found that cellophane tape The area of the vapor-deposited metal that adhered to and peeled off was 70% of the total area.
~100% peeling occurred over almost the entire surface.

Example 2 A mixture obtained by mixing 50 parts of polyethylene terephthalate with 50 parts of a copolymerized polyester composed of 10 mol % of sodium 5-sulfoisophthalate, 90 mol % of terephthalic acid, and an ethylene glycol component was mixed with the above example. A biaxially stretched film was obtained by melt extrusion, stretching, and heat setting in the same manner as in Example 1, and the results of a peel test on this biaxially stretched film were aluminum vapor-deposited in the same manner as in Example 1. %, and the vapor-deposited surface was hardly peeled off.

Claims (1)

[Claims] 1. A vapor-deposited polyester film, characterized in that a metal, metal oxide, or silicon oxide is vapor-deposited on at least one side of a film made of a modified polyester containing a structural unit having a sulfonic acid metal salt as a side chain.