JPS6180147A - Photographic support and its formation - Google Patents

Abstract

PURPOSE:To prevent defective coating by passing a photographic support having a polymer resin layer twice or more through a corona discharge region formed with relatively low frequency AC. CONSTITUTION:A photographic support having a polymer resin layer is passed at least twice through a corona discharge region formed with relatively low frequency AC by relative traveling, and/or the support is passed through at least two such discharge regions. By this corona discharge treatment, defective coating such as uneven coating giving the grains of lauan or coating producing pinholes is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a photographic support, and more particularly to a photographic support treated to make it hydrophilic and a method for forming the same.

(Prior art) Conventional photographic materials are coated with constituent layers such as a light-sensitive emulsion layer in which light-sensitive silver halide particles are dispersed in a protective colloid such as gelatin, a protective layer, and an antihalation layer on a support. However, if the support is made of a hydrophobic polymer resin or has such a resin layer on its surface, adhesion with a constituent layer containing a hydrophilic protective colloid as binder In order to improve this, the support is subjected to hydrophilic treatment.

One such hydrophilic treatment is corona discharge treatment, and preferred treatment methods and conditions are disclosed in, for example, US Pat. No. 3,549,406.

However, when constituent layers of a photographic light-sensitive material are coated on a support that has been subjected to a conventionally known corona discharge treatment, coating failures such as launch-like coating unevenness and pinholes may occur.

(Object of the Invention) An object of the present invention is to provide a photographic support free from the above-mentioned coating failure, and a second object is to provide a method for forming such a support. be.

Supports treated with high-frequency discharges have good adhesion of the hydrophilic layer, but the aforementioned coating failure occurs, and supports treated multiple times with low-frequency discharges have It has been found that it has adhesion properties that are as good as those of the treated support, and that the coating failure described above does not occur.

That is, the object of the present invention is achieved by a photographic support characterized in that it has a layer made of a polymeric resin and has been exposed to a corona discharge region due to relatively low frequency alternating current two or more times.

Furthermore, a second object of the present invention is to run a photographic support having a layer made of a polymeric resin relative to a corona discharge region caused by a relatively low frequency alternating current, and to extend the discharge region at least twice. This is achieved by a method for forming a photographic support characterized by passing through the discharge region twice and/or at least two times.

The present invention will be explained in more detail below.

The support having a layer made of a polymeric resin according to the present invention may be a polyester base (for example, polyethylene terephthalate, cellulose acetate, polycarbonate, etc.), a polyvinyl chloride base, a polystyrene base, a polyolefin coated paper, etc. Among the supports used for the material, polyolefin-coated paper (for example, polyethylene-coated paper) is particularly effective in the present invention.

Since the support of the present invention is exposed to the corona discharge region caused by relatively low frequency alternating current twice or more, the above-mentioned coating failure can be prevented. 200Hz as a low frequency
It is preferable that the frequency is less than 1, and any frequency may be used as long as it can generate a discharge stream with a certain degree of density.

The corona discharge treatment is preferably carried out at a relative running speed of 20+++/min to 250+a/min while the support is continuously running and/or while a corona discharger is moving. If the speed is too low,
The residence time of the support in the corona discharge region becomes longer and the surface of the support becomes rough, and if the speed is too high, a high voltage is applied to obtain the effect of modifying the support surface, so please stop. This causes inconveniences such as being cluttered and not being easy to operate.

The degree to which the support surface has become hydrophilic depends on the wettability of the support surface, i.e., the angle at which the droplet contacts the support surface when a droplet of water (usually distilled water) is applied. can be evaluated. When the contact angle is about 35" to 75°, the adhesion of the photographic constituent layer to the support is good.

Furthermore, when coating a photographic constituent layer on the support according to the present invention, step-like coating unevenness may occur, but this is, for example, as described in U.S. Pat. This is thought to be due to the charging pattern caused by corona discharge. Therefore, before applying the above-mentioned coating, some means may be used to uniformize the charging state (e.g., U.S. Pat. No. 3,531
, No. 314), it is necessary to remove the charge. When the support is passed through ionized air before coating, the charges are neutralized and removed, and coating unevenness in the form of horizontal steps 4 no longer occurs. The support of the present invention is preferably coated after being passed through an ionized air atmosphere formed by an alternating current ion generator.

In addition, it is better to apply the photographic constituent layer on the support of the present invention after a considerable period of time than to apply the photographic constituent layer immediately after the low-frequency corona discharge treatment, in order to prevent only the horizontal step-like coating unevenness described above. First, it is preferable because it can also prevent uneven coating and pinholes.

That is, it is preferable to wait at least 30 minutes before applying.

The present invention will be described below with reference to Examples, but the embodiments of the present invention are not limited thereto.

(Example) Four layers of the following coating solution were applied to a medium 100 cm polyethylene foot paper using a slide hopper under the corona treatment conditions and coating speed shown in the table. The temperature of the coating liquid was 38°C.

[Coating liquid]

1. Silver halide emulsion (breast milk) Contains 0.53 mol/q of silver chlorobromide containing 20 mol% of silver bromide, 10% gelatin solution, antifoggant and other additives used in mines.

(Emulsion AI)...Blue-sensitive yellow coloring emulsion The above breast milk was sensitized to blue sensitivity and the following yellow coupler (0,40
A dispersion of DBP oil droplets of 1 mol of Ag) in a gelatin solution was further mixed with gelatin 'O, (added gelatin n,) added to adjust the gelatin content, diluted to 6% with respect to gelatin, and a coating solution was prepared. Finished.

(Emulsion Bl)...Green-sensitive magenta coloring emulsion Breast milk sensitized to green sensitivity by the same procedure as the above emulsion A1 and DBP of the following magenta coupler (0.20 mol 1 mol Ag)
A coating solution containing 6% gelatin was prepared using the oil droplet dispersion and the added gelatin solution.

2. Intermediate layer solution... 5% gelatin solution 3. Preservation f1
Layer solution: 5% gelatin solution yellow capra magenta coupler Coating is done 2 hours after corona discharge treatment.
In addition, an AC ion generator was installed in front of the slide hopper.

As is clear from the table, it can be seen that coating failures do not occur when corona discharge treatment is performed twice or more using low-frequency alternating current.

Claims (1)

[Scope of Claims] 1) A photographic support having a layer made of a polymer resin and having been exposed to a corona discharge region caused by relatively low frequency alternating current two or more times. 2) The photographic support according to claim 1, wherein the frequency of the alternating current is less than 200 Hz. 3) The photographic support according to any one of claims 1 to 2, wherein the polymer resin is polyolefin or polyester. 4) A photographic support having a layer made of a polymer resin is moved through a corona discharge zone caused by a relatively low-frequency alternating current at least twice and/or at least two times. A method for forming a photographic support, which comprises passing through a discharge region. 5) The method for forming a photographic support according to claim 4, wherein the frequency of the alternating current is less than 200 Hz.