JP2003082133A - Method for surface treatment of plastic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for surface treatment of a plastic film, which can stably improve various suitabilities such as wettability, printability, suitability for setting, and bondability. SOLUTION: Discharges are induced by an RF system in a nitrogen-oxygen gas mixture to generate a low-temperature plasma of the gas mixture, and a base material comprising a biaxially oriented nylon film (Emblem ON, a product of Unitika Ltd.) is subjected to surface treatment with the low- temperature plasma. Discharges are induced by the RF system in hydrogen gas to generate a low-temperature plasma of the gas, and the base material is then subjected to surface treatment with the low-temperature plasma.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a surface treatment method for a plastic film, which is excellent in printing and printability.
Alternatively, it relates to a method for producing a plastic film having excellent adhesiveness when laminated. More specifically, the present invention relates to various kinds of printing plastic films such as gravure printing base materials, inkjet image-receiving papers, OHP films, and laminated films for packaging materials.

[0002]

2. Description of the Related Art As a recent situation in printed matter, further beauty is required. In addition, as part of the IT boom, high-performance color printers have become widespread in general households as well as personal computers, and the number of applications for printing directly on plastic film such as inkjet image-receiving paper and OHP film is increasing. . In addition, water-based inks are widely used in recent popular machines. A plastic film which is directly printed or printed with such a water-based ink is required to have various physical properties such as surface wettability, printability and printability.

In addition, with the diversification of packaging forms, there are various occasions where films are laminated, and in this case also, it is necessary to improve the wettability and adhesiveness of the surface, or to stabilize the adhesiveness. It is increasing. Conventionally, in order to improve the above-mentioned suitability, a plastic film provided with an undercoat layer on the surface or treated with corona or the like has been sold in the market and is generally used. However, the above-mentioned requirement level tends to be high, and in some cases, the conventional method alone cannot be satisfied.

[0004]

In view of the above background, an object of the present invention is to provide a surface treatment method for stably improving various suitability such as wettability, printability, printability, adhesion suitability and the like. .

[0005]

The present invention has been made as a result of intensive studies for solving the above-mentioned problems, that is, the invention according to claim 1 has a nitrogen-oxygen mixture on at least one surface of a plastic film. This is a surface treatment method for a plastic film, which is characterized by performing a low temperature plasma treatment having a gas as a component and then performing a low temperature plasma treatment having a hydrogen as a component.

Examples of the plastic film include polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamides, polycarbonate, polyacrylonitrile, polystyrene, polyvinyl chloride, cellulose, triacetyl cellulose,
It is possible to use those having at least one kind of polyvinyl alcohol and polyurethane as a component, having as a copolymerization component, or having a chemically modified product thereof as a component.

Preferred among these plastic films are nylon-6, nylon-6,6 and nylon-12.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the following, further details will be described. The plastic film here means a film of a known polymer compound. In the polymer compound, but not limited to, polyolefin compounds, polyester compounds, polyamide compounds, polyurethanes, polyimides, polyether sulfones, polyethers, epoxy resins, alkyd resins, glyptal resins, polysaccharides, proteins Examples include (polypeptide).

As particularly preferable examples, polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamides, polycarbonate, polyacrylonitrile, polystyrene, polyvinyl chloride,
Examples thereof include a plastic film having at least one kind of cellulose, triacetyl cellulose, polyvinyl alcohol and polyurethane as a component, having as a copolymerization component, or having a chemically modified product thereof as a component.

Among them, nylon-6, nylon-
Those using 6, 6 and Nylon-12 exhibited remarkable improvement in physical properties.

These plastic films are used for
It should be selected as appropriate according to the cost and workability.

The low-temperature plasma referred to here is a known method such as general DC glow discharge, horocathode type DC discharge, holoanode type DC discharge, high frequency discharge, microwave discharge, and the like. It is not limited to. The processing conditions indicated by processing speed, energy level, etc. should be appropriately set according to the type of substrate, application, discharge device characteristics, and the like. Gas species of plasma require nitrogen / oxygen mixed gas in the first step and hydrogen in the second step. However, mixing other gas species in addition to these does not exceed the scope of the present invention. For example, when hydrogen or the like is excessively sucked by the pump, it is possible to add argon gas or the like. The gas flow rate should also be set appropriately according to the application, substrate and device characteristics.

[0013]

EXAMPLE An example of implementation will be shown. The examples provided here are not meant to limit the invention. Examples 1 and 2 Using a general biaxially stretched nylon film having a thickness of 15 microns (Unitika Ltd .: Emblem ON) as a base material, a low temperature plasma treatment of a radio frequency (RF) discharge method was performed under the conditions shown in Table 1. . The conditions are shown in Table 1.

Comparative Examples 1 to 4 Similar to the examples, the low temperature plasma treatment of the RF discharge method was performed. The conditions are shown in Table 1. Further, Comparative Example 4 is not subjected to plasma treatment.

[0015]

【table 1】

[Evaluation method] -Measurement of contact angle Wetness (printing, printing,
It was used as an index of alternative physical properties of printing and adhesive properties. As the measuring instrument, an automatic contact angle meter CA-Z type manufactured by Kyowa Interface Science Co., Ltd. was used.

-Measurement of printability After the films subjected to the respective treatments were fixed on the mount by using a double-sided tape, the printability was observed using a color ink jet printer (EPSON: PM-800C). . The evaluation was performed by observing the fineness (the small amount of bleeding or the like considered to be caused by the cissing) with an optical microscope.

Evaluation of adhesive strength An LLDPE film (manufactured by Tohcello Co., Ltd .: FC) by a dry lamination method using a commercially available polyurethane adhesive
-S, thickness of 60 microns) and then 50 ℃
-Aged for 2 days. Peeling tester (Orientec Co., Ltd .: Tensilon universal testing machine RTC-1250)
Was used to measure the laminate strength according to JIS1707.

[Evaluation Results] Table 2 shows the evaluation results.

[0020]

[Table 2]

From these results, the films of Examples 1 and 2 which were treated by the plasma of nitrogen-hydrogen mixed gas as in the present invention and then by the hydrogen plasma were more contact angle than Comparative Examples 1 to 4. Is significantly reduced, that is, the wettability is improved, there is little repellency in actual printing, the printability is good, and the adhesive strength is also excellent.

[0022]

According to the present invention, a plastic film having good wettability and excellent printability and printability can be obtained. Further, since it has excellent wettability, it has excellent adhesive suitability for adhesives and can be applied to adhesive lamination with other plastic films.

Continued front page    (72) Inventor Noboru Sasaki             1-5-1 Taito, Taito-ku, Tokyo Toppan stamp             Imprint Co., Ltd. F-term (reference) 2C056 FC06                 2H086 BA19                 4F073 AA01 BA03 BA07 BA08 BA13                       BA17 BA18 BA19 BA24 BA28                       BA29 BB01 CA01

Claims (3)

[Claims] 1. A surface treatment method for a plastic film, which comprises subjecting at least one surface of the plastic film to a treatment with a low temperature plasma having a nitrogen-oxygen mixed gas as a component, and then performing a low temperature plasma treatment having a hydrogen component as a component. 2. The plastic film is at least one of polyethylene, polypropylene, polyethylene terephthalate, polyethylene naphthalate, polyamides, polycarbonate, polyacrylonitrile, polystyrene, polyvinyl chloride, cellulose, triacetyl cellulose, polyvinyl alcohol, polyurethane. 2. The surface treatment method according to claim 1, wherein the component is contained in the component, the copolymer component is contained, or a chemically modified product thereof is contained in the component. 3. The plastic film is nylon-
6. The surface treatment method according to claim 1, wherein the surface treatment method is nylon-6,6, or nylon-12.