DE1284295B - Photographic film with antistatic backing - Google Patents

Description

1 2

The invention provides a photographic antistatic backing layer that consists of a

Film with a slippery, antistatic backing layer. of the following are known per se as antistatic agents-

It is known that photographic film material consists of products: firstly, polyaddition compounds

in the production and processing to a large extent with sulfo groups substituted diaminodiphenyl tends to build up electrostatic charges. In the case of the 5 ethane and toluene diisocyanates, secondly salts

Discharge occurs so-called "flashes", those of esters of polyacrylic or methacrylic acid with

on a developed material as a defect in the form of ethanolamine or its derivatives or thirdly

localized overexposure can be seen. Acetals of polyvinyl alcohol with benzaldehyde and

Such flashes can most safely be carried out using benzaldehydes substituted with acidic groups,

avoid if the electrical conductivity of the film is good and also 20 to 50 percent by weight of one

surface, e.g. B. by applying suitable anti-saturated aliphatic alcohol or an aliphatic

static substances, is so increased that forming tables carboxylic acid with 14 to 18 carbon atoms

Electrostatic charges drain away in the shortest possible time as contains lubricant.

can. Since the emulsion side by its lower suitable lubricants are e.g. B. Tetradecanol- (1) Surface resistance is generally only low in 15 [myristyl alcohol], hexadecanol (1) [cetyl alcohol], Measures for the generation of electrostatic charges Occurrence Octadecanol- (1) [stearyl alcohol], myristic acid, Palzut, antistatic substances are preferred to mitic acid and stearic acid.

the uncoated side of the film material for application. bring antistatic layers with good sliding properties

In addition to antistatic protection, ao speed is considerably simplified. Instead of the previous two

Film material requires a certain lubricity in order to be able to work or apply for a

the frictional forces on the film surface to a slidable antistatic layer from the specified

wrestle. This has z. B. Significance for 35mm films, NEN substances is only one operation or

where the forces required to pull out the film are machine-only required by one application,

from the cartridge are required as low as possible 25 In addition, additional solvents for the

want to keep the perforation from tearing out on the separate application of the wax layer or costly

Prevent take-up reel of the camera. Even with old systems for their recovery.

Motion picture and narrow films give insufficient gliding The mentioned functional derivatives of aliphatic

ability values for sensitive mechanical impacts hydrocarbons can, because of their favorable

cause. 30-hour solubility properties in a large

It is therefore customary to apply advertising-coated on the back of a one-sided richly different solvent systems Footage except for an anti-static den. Mixtures of acetone and are particularly suitable Layer another layer of wax to apply to such low aliphatic alcohols as methanol or to obtain the required lubricity. This ethanol. The casting solutions for the antistatic Driving requires additional expenses for the 35 layers should preferably 0.1 to 1 weight application the wax layer. It may be a percent of the antistatic substances and 0.1 to Second work step necessary, but at least 1.0 percent by weight of the sliding width according to the invention Applicant. Contained for the application of wax agents. The lubricants need to be in the anti-layer solvent used will be lost or static layer in a concentration of 20 to must be regained. 40 50 percent by weight should be included. Are preferred

It is already known that antistatic backing layers have concentrations of 20 to 40 percent by weight. Alkali metal salts of fatty acids with 8 to 18 carbons. In practice one proceeds in such a way that the invention atoms add lubricants according to the invention to the organic solutions to improve the lubricity. Furthermore, saponification products of esters are dissolved and this stock solution is the antistatic Fatty acids and fatty alcohols as additives to solutions at the end or to another suitable solution Emulsions or protective layers known. Such a point in time of the preparation process adds. The cheapest However, salt-containing substances have the disadvantage that the amount depends on various factors, limited solubility. In particular, they are in organic- mainly on the amount of antic used Solvents only partially soluble, in the meistatic substance, its surface mechanical are even insoluble. 50 properties and the solvent used - this disadvantage is all the more serious as an anti-mix. However, the amount of lubricant shouldn't static layers in many cases made of organic may be higher than that of the antistatic substance. Solvents are applied. This is advantageous although the lubricants according to the invention are practical Adhesive, because this causes the film base to swell - with no or only very low electrical conductivity, Cellulose acetate films, for example, have a lower conductivity than that for 55 in any case Acetone to -, whereby an improvement in the abrasion anti-static substances used will have The surface resistance of the additive does not achieve the strength of the antistatic backing layers will. In addition, the solubility of the known ones is significantly impaired. It is by no means higher than fatty acid salts in the presence of other salts, with separate application of wax layers, among other things, also salt-containing polymers in many cases further impaired, so that there are no films made from cellulose esters or polyesters that are completely common in the industry Application solutions and no optically flawless styrene, vinyl chloride polymers, polyester, polyclear Layers. carbonate or other high molecular weight substances a-The invention is based on the object to be set. The solutions of the antistatic subphotographic Film with slidable antistatic 65 punch with added lubricants according to the backing layer To develop the above gender invention can be done in the immersion process or in Does not have disadvantages. Rinsing process applied to the back of the film. A photographic film with a be. In the immersion process, a tub is used

Solution raised until the film web, guided by a roller, is wetted. In the case of the rinsing process a roller with a separate drive that is immersed in the solution transfers the solution to the directly above it, guided by a second roll of film.

In order to be able to assess the effectiveness of the additives according to the invention for antistatic layers, it is necessary to determine the lubricity. In practice, the frictional resistance is measured as the reciprocal value of the sliding ability. For this purpose, two 35 mm wide and approximately 80 cm long strips are cut out of the film material in question, the layer to be tested is turned towards one another and placed horizontally. Weighed down with a weight of 500 g and about 12 cm ² base area and measured the force required to move the upper strip against the lower one.

The electrical conductivity of the surface is used to assess the antistatic effectiveness of the layers. Its reciprocal value, the surface resistance, is measured at 65% relative humidity between 10 cm wide standard electrodes, which are arranged at a distance of 1 cm.

The following examples illustrate various embodiments of the invention.

example 1

2 g of stearyl alcohol are added to the solution of 5 g of a polymer of 4,4'-diaminodiphenylethane-2,2'-disulfonic acid sodium and toluylene diisocyanate in 45 ml of H ₂ O, 150 ml of methanol and 800 ml of acetone. The solution is brought in Anspülverfahren on the back of a photographic film base of cellulose triacetate (60.6% acetic acid) and dried with hot air of 8O ⁰ C. For comparison, a corresponding solution without the addition of stearyl alcohol is plotted, half of which in a second operation, is provided with a separate wax layer according to the prior art. The measurements result in the following values:

Antistatic layer with
separate wax layer according to the state
of the technique

Antistatic layer with
inventive addition of stearyl alcohol

Antistatic layer without
Addition of stearyl alcohol

Surface resistance

2.0 x 10 ⁸ ohms

1.3 x 10 ⁸ ohms

1.2 x 10 ⁸ ohms

Sliding ability

45

208 g

192 g

268 g

Example 2

3 g of stearic acid are added to ethyl sulfate in 200 ml of methanol and 800 ml of acetone. One wears in the wash-up process on a cellulose triacetate support (60.6% acetic acid) and dried with warm air. Comparative experiments as in Example 1 are carried out. The following measured values result:

Antistatic layer with
separate wax layer according to the state
of the technique

Antistatic layer with
inventive addition of stearic acid ..

Antistatic layer without
Addition of stearic acid

Surface resistance

3.3 x 10 ⁷ ohms

2.5 x 10 ⁷ ohms, 3.0 x 10 ⁷ ohms

Sliding ability

350 g

170 g> 400g

Example 4

A solution of 5 g of a mixed acetal of polyvinyl alcohol with benzaldehyde and benzaldehyde-2,4-disulfonic acid Sodium in a ratio of 1: 1 in ml of water, 190 ml of methanol and 800 ml of acetone 2.5 g of stearyl alcohol are added. The solution is applied to a cellulose acetate support (59.8% acetic acid) worn and dried with warm air. As in Example 1, comparative tests are carried out without any additive a lubricant and carried out with a separate wax layer according to the prior art. The following measured values are obtained:

Antistatic layer with
separate wax layer according to the state
of the technique

Antistatic layer with
inventive addition of stearyl alcohol

Antistatic layer without
Addition of stearyl alcohol

Surface resistance

2.5 x 10 ⁸ ohms 2.2 x 10 ⁸ ohms 1.5 x 10 ⁸ ohms

Sliding ability

190 g 200 g 280 g

Claims (3)

Claims: 55 To a solution according to Example 1, 2 g of myristic acid are added. After application to a cellulose acetate layer carrier (60.6% acetic acid) the following values are obtained: Surface resistance 9.6 · 107 ohms Slidability 220 g Example 3 A solution of 5 g of a polymer of / 3-methacrylylhydroxyethyl-methyl-diethyl-ammonium-me - 1. Photographic film with an antistatic backing layer, characterized in that that the antistatic backing layer consists of one of the following per se as antistatic Agents known products: firstly, polyaddition compounds from substituted with sulfo groups Diaminodiphenyläthanen and toluylene diisocyanates, secondly salts of esters of polyacrylic or -methacrylic acid with ethanolamine or its derivatives or thirdly acetals of polyvinyl alcohol benzaldehydes substituted with benzaldehyde and acidic groups, and also 20 to 50 percent by weight of a saturated aliphatic alcohol or an aliphatic carboxylic acid containing 14 to 18 carbon atoms as a lubricant. 2. Photographic film according to claim 1, characterized by combining a known carrier made of cellulose esters with a antistatic backing layer consisting of a polyaddition product of sulfo groups substituted Diaminodiphenyläthanen with toluene diisocyanates and also 20 to 50 percent by weight an aliphatic alcohol or an aliphatic carboxylic acid having 14 to 18 carbon atoms contains. 3. Photographic film according to claim 1, characterized in that in the antistatic Backing layer 20 to 40 percent by weight of an aliphatic alcohol or an aliphatic carboxylic acid with 14 to 18 carbon atoms are included.