JPS6016614B2 - Surface treatment method for polyester film for photographic material support - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for surface treating a polyester film for use as a support for photographic light-sensitive materials.

More specifically, the present invention relates to an improved vacuum glow discharge treatment method for polyester films for photographic material supports. Conventionally, plastic films, metal plates, etc. have been treated with corona discharge treatment, vacuum glow discharge treatment, electrodeless plasma discharge treatment, ultraviolet irradiation treatment, etc. for the purpose of improving the adhesion of the resin layer or metal layer provided on the surface. Various surface treatments are performed.

For example, Tokuko Sho 35-17578, Sho 36-10 No. 6, Sho 45-22004, Sho 45-22005, Sho 4
No. 5-24040, No. 46-43480, U.S. Patent 3
No. 057792, No. 3057795, No. 317948
No. 2, 32 spots, grade 6, paper No. 09299, 342473
No. 5, No. 3462335, No. 3475307, No. 37
6129, British Patent No. 997093, etc., it is known to subject polymers to vacuum glow discharge treatment for the purpose of improving adhesion, hydrophilicity, dyeability, etc.

These methods improve the hydrophilicity, adhesion, and dyeability of the polymer, but the glow 0 discharge required to firmly bond the emulsion layer in the photographic material to the polymer film that is the support is insufficient. There was a drawback that the polymer film was colored yellow when the treatment was carried out. This coloration not only poses a problem in terms of product image, but also causes extremely serious defects in practical use, especially in lithographic photographic materials, as it absorbs ultraviolet rays during exposure, resulting in longer baking times. Therefore, when performing surface treatment, consideration must be given to suppressing this coloration as much as possible.
However, in the conventional technology, if the degree of surface treatment is reduced in order to suppress coloring, depending on the type of photographic emulsion, the adhesion between the polymer 0 support and the photographic emulsion becomes extremely poor, resulting in a fatal defect in practical use. Put it away. Therefore, especially in the field of photographic materials where hue and transparency are strictly required, a method that can obtain good adhesion with a small amount of coloring is desperately desired and its appearance has been eagerly awaited. One object of the present invention is to provide a method for surface treatment of a polyester film for use as a support for photographic light-sensitive materials, which suppresses coloring and provides good adhesion.

Another object of the present invention is to provide a method for surface treatment of a polyester film for use as a support for photographic light-sensitive materials, which shortens the surface treatment time and provides good adhesion. Other objects of the invention will become apparent from the description below.
In order to achieve this objective, the present inventors have conducted intensive research and found that by keeping the polyester film in a heated state during vacuum glow discharge treatment, a sufficiently high adhesive strength can be obtained and the coloring can be reduced to 1/4 to 1/4 of the conventional level. I realized that it was possible to reduce the amount to 1/5, and decided to do so.

That is, the surface treatment method of the present invention is characterized in that the vacuum glow discharge treatment is performed in a state where the surface temperature of the polyester film is 80 qo or more and 180 oo or less. According to the method of the present invention, the adhesiveness of the polyester film can be significantly improved in an extremely short treatment time, and the degree of coloring of the polyester film incidentally caused by the discharge treatment can be greatly reduced. By simply heating the polyester film to be treated, the yellow coloration of the polyester film, which could not be alleviated even by varying various conditions such as vacuum degree, gas composition, voltage, etc. during vacuum glow discharge treatment, can be alleviated. It is quite surprising that the number can be reduced to the middle of the day. In particular, it is extremely surprising that yellowing can be reduced even though vacuum glow discharge treatment under heating is thought to promote yellowing of a polyester film for a support of a photographic light-sensitive material to be treated. The effect of preventing rhombus discoloration of the polyester film for use as a support for photographic light-sensitive materials according to the present invention can be observed even when processed at temperatures lower than 80 oz, but it usually becomes noticeable at temperatures above 80 qo. Therefore, the surface temperature of the polymer can be increased from 80 to 18,000.
It is appropriate to carry out the vacuum glow discharge treatment as follows.
Specific methods for increasing the polymer surface temperature in a vacuum include heating with an infrared heater and heating by contacting with a heated roll. There is no heat loss due to thermal conduction, so heating can be performed very efficiently.

For example, if you want to heat the film surface to 100℃,
It is sufficient to contact the film with a heated roll at 0° C. for at most 1 second. Examples of the polyester film of the present invention include polyethylene terephthalate film and polybutylene terephthalate film.

The glow discharge treatment in the present invention can be performed using any conventionally known method, such as the method described in the above-mentioned patents.

A typical glow discharge treatment method will be described below. The pressure is 0.005 to 20 Tom, preferably 0.02 to 2
rom is appropriate. If the pressure is too low, the surface treatment effect will be reduced, and if the pressure is too high, an excessive current will flow and sparks will easily occur, which is dangerous and may even destroy the object to be treated. Discharge occurs by applying a high voltage between one or more pairs of metal plates or metal machines spaced apart from each other in a vacuum tank. This voltage can take various values depending on the composition and pressure of the atmospheric gas, but normally, within the above pressure range, stable steady glow discharge occurs between 500 and 5000V. A particularly suitable voltage range for improving adhesion is 2000-4000V. Electric discharge occurs when atmospheric gas molecules or atoms are ionized by a high electric field, and at this time, ions, electrons, excited molecules, ultraviolet light, visible light, and infrared light of various energy levels are generated. By placing the workpiece in this atmosphere, changes occur on the surface of the workpiece. At present, it is not clear which of the above-mentioned elements mainly contributes to the improvement of adhesion and which causes the coloration (yellow coloration) of the treated object. As mentioned earlier, in the conventional method, as the degree of surface treatment is increased, for example, as the treatment time is lengthened, the adhesion improves, but on the other hand, undesirable coloration of the treated material also increases. There was a relationship between them.

This relationship shows that even if the gas composition, voltage value, or pressure was changed, the coloration was always the same when the treatment was performed to obtain a surface state with a certain adhesion level. However, by using the heating method of the present invention, it has become possible to dramatically break through this relationship and obtain the same adhesive strength while suppressing coloring to the conventional level. Furthermore, the method of the present invention has the advantage that it is possible to provide adhesive properties equivalent to those of the conventional method in a processing time longer than that required.
Furthermore, the present invention has made it possible to put polyester films subjected to vacuum glow discharge treatment into practical use as supports for photographic materials that require extreme performance, particularly in terms of transparency and hue. As a result, compared to the conventional method of providing a so-called subbing layer, which had to be used to sufficiently bond the photographic layer and the polyester film support, the process and raw material costs are extremely low. An adhesive method was provided. Furthermore, in terms of the quality of the obtained photographic material, it can be said to be extremely excellent, as there are no coating failures associated with the application of the undercoat layer, and the lack of an extra layer leads to an increase in resolution. Furthermore, unlike the case where a conventional undercoat layer is applied, no industrial waste is generated, which is extremely meaningful from a social and environmental standpoint.
Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Four half-circle electrodes each having a length of 40 mm and having a diameter of 2 mm in cross section were fixed on an insulating plate at intervals of 10 mm.

Fix this electrode plate in a vacuum tank, and
A two-scale stretched polyethylene terephthalate film with a thickness of 100 mm and 30 mm was run so as to face the electrode surface at a distance of 5 mm. Immediately before the film passes over the electrode, the film is heated with a temperature controller of 5 mm in diameter. - By arranging a heating roll so as to touch the reeds and placing a thermocouple thermometer in contact with the film surface between the heating roll and the electrode zone, it was possible to control the film surface temperature to a desired temperature. In this way, by appropriately adjusting the film feeding speed and heating roll temperature, it became possible to control the glow discharge treatment time and film surface temperature of various pears. Glow discharge discharges the inside of the tank to 0.0
This was carried out by applying a voltage of 3000V to the above electrode while maintaining the voltage at 5Ton. At this time, the electrode current is 0.4
It was A. The processed films obtained by changing the base surface temperature and processing time were coated with a conventional gelatin-silver halide photographic emulsion for Lith-sensitive materials, and the level of adhesion was tested.

To determine the level of adhesion, use a razor to make six square cuts on each side of the prepared silver halide photographic film, and apply adhesive tape (Nitto Polyester Tape) on top of this. ), and use your hand to forcefully press 1.
The adhesive tape was peeled off in the 8-axis direction, and the adhesive strength was ranked as A, B, or C depending on how the emulsion film peeled off. A: No peeling at all, B: Partial peeling, C:
means that it will peel off completely. On the other hand, the coloring of the glow discharge treated film was measured using a Necbeth densitometer.
It was measured at a wavelength of 660A and evaluated as the difference in optical density from the untreated film. That is, degree of coloring=△D3660=[
3660A optical density of surface treated film] - [36600A optical density of untreated film]. The results obtained are summarized in Table 1. Table 1 As is clear from Table 1, in order to obtain A-grade adhesive strength using the conventional method of glow discharge treatment without heating, 0.0
However, if the heating method of the present invention is adopted, the degree of coloration is reduced, especially from 90 to 120 degrees.
When heated to a temperature of 1'5, a grade A adhesive strength can be obtained with a degree of coloration of 1'5.

In addition, the glow discharge treatment time required to obtain good adhesive strength can be reduced by 0.5 seconds from 2.5 seconds. This means that when using a discharge treatment zone of 30 skins as in this example, the wetting speed was 7.2 m/mjn in the conventional method, but with the method of the present invention, it was five times faster at 36 m/min. This means that it is possible to process Example 2 Using the same equipment as in Example 1, a double-stretched polyethylene terephthalate film was heated to 0. is o
m', apply a voltage of 1500 V, and do not heat (2
Glow discharge treatment was performed under heating conditions of 500) and 100C◯.

The treated film was coated with a gelatin-silver halide emulsion commonly used for X-ray sensitive materials, and the adhesive strength and degree of coloring were evaluated in the same manner as in Example 1. Table 2 shows the minimum processing time required to achieve an A-grade adhesion level and the degree of coloring in that case. Table 2 As is clear from Table 2, in order to obtain grade A adhesive strength with the conventional glow discharge treatment without heating, the degree of coloration must be 0.
However, according to the present invention, desired coloring can be obtained with about 1/4 the degree of coloring.

The present invention also includes the following embodiments.

{1' In the claims, vacuum glow discharge is 0.0
A method of carrying out under a pressure of 0.05 to 2 orr, preferably 0.02 to phantom orr.

■ In the claims, the discharge pressure is 500 to 500.
A method carried out at 0V, preferably 2000-4000V.

Claims (1)

[Claims] 1. In a method for vacuum glow discharge treatment of a polyester film for use as a support for photographic light-sensitive materials, the surface temperature of the polyester film is set at 80° C. or higher to 180° C. when undergoing the discharge treatment.
1. A method for surface treatment of a polyester film for use as a support for photographic light-sensitive materials, characterized in that a discharge treatment is performed at a temperature of 0.degree. C. or below.