DD246634A1 - PROCESS FOR SUBSTRATING HYDROPHOBER PHOTOGRAPHIC MEDIA - Google Patents

Abstract

The object and the object of the invention to find compounds for use in subbing solutions for photographic support materials which ensure improved surface properties without adversely affecting the adhesion properties of the substrate layers and the photographic parameters are achieved by exposing the surface-forming adhesive layer in a concentration range of 5 to 5. 30 wt .-%, based on the dry weight of the binder, imidazolines of the general formulas I or II is added.

Description

or II '

Χ ^θ

R = alkyl radical having 8 to 38 C atoms, substituted or unsaturated;

R ₁ = H ^ CH ₂ -CH ₂ -OK ₁ H;

OLJ Γ * LJ ·

2 - '- »ns, ^ 2 ^ 5 /

X = CH, -SO, Cl, Br, CH - / \> - S0,

mean, added.

2. A process for the substrate of hydrophobic photographic support materials according to item 1, characterized in that is used as the surface-forming adhesive layer B an aqueous-organic gelatin dispersion, which may be both acidic and alkaline stabilized used.

Field of application of the invention

The invention relates to a method for the substrate of hydrophobic photographic support materials having improved surface properties.

Characteristic of the known technical solutions

For firmly anchoring hydrophilic emulsion or auxiliary layers on a hydrophobic film support material during the production process of the recording material or before, during and after the film processing process, adhesion layers are usually used. Depending on the film base material used, an adhesive layer is sufficient, or several must be applied in a subbing process. So z. For example, for polyethylene terephthalate film supports (hereinafter referred to as PETP), adhesion layer systems which may contain synthetic polymers and / or copolymers in the adhesion layer directly on the support and gelatin alone or in combination with other hydrophilic macromolecular substances in the top layer are common.

The surface quality of salable support materials is determined by the surface properties of the applied adhesive layers. In the case of multilayer substrate systems, it is essentially embossed by the uppermost adhesive layer of the carrier material, although in principle influences due to interactions with the lower adhesive layer can not be ruled out.

The surface quality of these subbing layers does not imperceptibly affect the photographic parameters of the emulsion layers applied to them. The generally desired increases in subbing speed increase the risk of application failures in the form of wetting defects and inhomogeneities due to dissipative structural formation that may be caused by transport and mixing during film formation. Characteristic of these defects is a strong fluctuation range of the measured contact angle.

In conjunction with the current trend of subsequent application of extremely thin photographic layers which can no longer cover such defects, there is an increasing decrease in the utility properties of the resulting recording materials, which manifest themselves in increased density variations, color distortions and sharpness losses.

This results in the need to prevent the formation of said imbalances or to conceal them by appropriate measures.

To eliminate the surface defects described, selected surfactants or surfactant combinations are used according to the prior art. The aim is to avoid occurring gradients in the interfacial tensions with the use of surfactants and generally to ensure a high homogeneity of the contact angle.

From this point of view, German Offenlegungsschrift 2,400,372 uses perfluorocarbon compounds in plastic adhesive layer solutions as surface-active agents. A relatively highly concentrated adhesive layer system (1-10% by weight of fluorosurfactant based on the polymer weight) which is relatively high in fluorosurfactants is described, which certainly leads to general adhesion difficulties in a later high-temperature or automatic development of the photographic material.

In DE-OS 1 942665 anionic and nonionic, aliphatic perfluoro compounds based on saturated unbranched perfluorocarboxylic and perfluorosulfonic acids are claimed as wetting agents in gelatin-containing photographic materials for a uniform coating order.

Furthermore, DE-OS 2 309 076 uses cationic fluorosurfactants for coating highly surface-active layers and DE-OS 2309096 as a coating aid for improving the quality and uniformity of photographic layers and for improving their application and reproducibility. Also in the US-PS 4013696 and 3775126 fluorine-containing cationics are used as coating agents, but here in combination with propoxylated alkylphenols. All of the fluorosurfactants used in these patents are expensive, defined individual compounds which, in addition, subsequently undergo a blend with other surfactants in order to optimize their action behavior. In the Jap. PS 57-51093 and 57-12978 are used to improve the castability of the carrier materials copolymers consisting of methyl vinyl ether and maleic anhydride, in combination with anionic, nonionic or amphoteric surfactants or copolymer esters, consisting of styrene and maleic anhydride. Although these high molecular weight compounds are used only in low concentrations and the acid groups are partially esterified (Japanese PS 57-12978), the acid group content is still too high, so that in alkaline developers Saizbildung and thus water solubility can occur. This has the consequence that the adhesion of the hydrophilic layers is limited to the carrier material and a detachment (floating) of the hydrophilic layers is observed.

Object of the invention

The object of the invention is to produce photographic support materials with improved surface properties, wherein the adhesive properties of the substrate layers and the photographic properties of the recording material are not affected.

Explanation of the essence of the invention

The invention has for its object to find compounds for use in subbing solutions that change the layer morphology targeted and avoid the emergence of defects in the near-surface region. According to the invention, this object is achieved in that in a process for the substrate hydrophobic photographic support materials by means of an adhesive layer system consisting of one or more synthetic polymers containing adhesive layer (s) A and an adhesive layer B based on a hydrophilic colloid, the adhesive layer forming the surface B in a concentration range of 5 to 30 wt .-%, based on the dry weight of the hydrophilic colloid, imidazolines of the general formulas

or

II

wherein R

Ri R ₂ η

Alkyl radical having 8 to 38 C atoms, substituted or unsaturated; H, + CH ₂ -CH ₂ -OK ₁ H; CH3, C2H5J

1-4;

₄ ,

Cl, Br,

CH ₃ - / ~~ V:

mean, added.

Preferably, the surface-forming adhesive layer B is an aqueous-organic gelatin dispersion which may be both acidic and alkaline stabilized.

Due to the structural conditions of these imidazoline compounds (basic nitrogen atoms) interactions with the anionic groups of gelatin, the preferred binder of the adhesive layer composition according to the invention, are possible.

These interactions lead to conformational changes of the gelatin macromolecules. This makes it possible that the, formed on the basis of transport and mixing processes during film formation inhomogeneous areas of the surface of the gelatin adhesive layer are avoided and targeted influencing of the layer morphology by the use of imidazolines according to the invention is possible. The resulting layers have significantly improved surface properties which ensure very good castability of the backing material with respect to casting uniformity, even at high casting speeds> 60 m / min.

The improved surface properties are also reflected in a significantly reduced tendency of the substrate substrates to be wound up in a coiled state. So storage experiments resulted in 92% r. F. no gluing phenomena.

The use of the compounds according to the invention can be carried out in a relatively large concentration range from 5 to 30% by weight, based on the dry weight of the binder. Advantageously, concentrations of 15 to 25% by weight have been found.

Since the imidazolines of the invention have very good solubility properties (eg, in aqueous-methanolic systems), addition to the adhesive layer composition is possible at any point in the batch regime. Another advantage is that the use of imidazolines in both acid and alkaline stabilized gelatin dispersions is possible. The stability of the gelatin dispersion is not impaired by the addition of imidazoline even for long periods (> 4 weeks).

Also not affected are the physical-mechanical parameters of the application solution, such. As the viscosity. Thus, the application is guaranteed with the application systems known in the art. The adhesive properties of the support material are not changed by the imidazoline addition, regardless of the development regime carried out.

The use of automatic processors ensures alcohol resistance and edge strength.

The composition of the lower adhesive layer directly on the carrier material is relatively uncritical. As adhesion promoters in the lower adhesive layer MSA copolymers have, as z. B. in GB-PS 920352, DD-PS 218484 and WP G.03 C 276494 are proven. They are applied to the polyester film support as acetone solutions which additionally contain p-chloro-m-cresol as the PETP solubilizer. The determination of the adhesion behavior, the sticking tendency and the pourability were carried out according to the following regulations.

a) adhesion test with the dry film before processing

The test piece which has been coated with an emulsion layer is cut in and, by means of tearing under shear stress, determines the emulsion surface which can be detached from the film support by this method. Note T means that no release of the emulsion layer occurred; Note 5 stands for a> 8mm wide separation of the emulsion layer. The intervening notes characterize the distant surface <8mm. The finished photographic film material is only applicable if the dry adhesion gives the marks 1 or 2.

b) adhesion test with the wet and swollen film during processing (edge peeling test)

The respective test sample treated in a developer and a fixer and still wet and swollen is rubbed strongly with the thumb from the edge of the photographic layer toward the inside in a horizontal direction perpendicular to the edge. When the photographic layer is peeled off, the edge peeling resistance is referred to as "bad." If the photographic layer does not peel off, the edge peeling resistance is judged to be "good." Usability is only given in the assessment "good".

c) Verification of the adhesion

Two strips of the subbed film support material with the dimensions 15 χ 3.5cm are left for two hours in a desiccator with 92% rel. Humidity (supersaturated Na ₂ CO ₃ solution) stored. Thereafter, the subbed sides are contacted with each other by passing through a roller mill and stored under load with 2kg for 12h. After another 12-hour storage without load, the strips are separated and the range of adhesion evaluated to assess the extent of adhesion

 The assessment is based on the following scale:

Rating ' State A. - 0-10% of the surface adhere B 10-40% of the surface adhere C 40-60% of the surface adhere D 60% or more of the surface adhere

d) Determination of the pourability of the subbed substrate. By means of Schlitzbeguß a colored gelatin solution is applied to the substrate at film speeds of 40-80 m / min under defined conditions. Immediately after the application, the determination of the extinction variations occurring as a result of inhomogeneities of the surface of the adhesive layer occurs. The extinction variations as a function of the film speed (and thus the applied wet film thickness) are used to assess the castability. Support materials with excellent castability are characterized by extinction fluctuations <4.5% at film speeds> 60 m / min (wet film thickness <30μΓη).

The advantages of the invention are explained in more detail in exemplary embodiments. The following compounds according to the invention are used in the examples:

Compound 1: imidazoline derallg. Formula II wherein R = (CH ₂ ) T-CH = CH- (CH ₂ ) T -CH ₃ R i - HR ₂ = CH ₃

Compound 2: imidazoline derallg. Formula II wherein R = (CH ₂ ) U ₅ -CH ₃ R ₁ = CH ₂ -CH ₂ -OH R ₂ = CH ₃

X = CH ₃ -SO ₄ . Compound 3: imidazoline allergy. Wherein R = (CH ₂ ) ₁₆ -CH ₃ R ₁ = H.

embodiment

example 1

On a biaxially oriented and heat-set polyethylene terephthalate film support is an adhesive layer A, consisting of 1 g of methyl methacrylate-maleic acid copolymer (according to GB-PS 920352) 10g p-chloro-m-cresol

100ml acetone, '

applied. The drying takes place at 135 ⁰ C and two minutes. The dry coating amount is 0.35 g / m ² . On this adhesive layer is an adhesive layer B, consisting of 4.2 g of gelatin 98 ml of water 9.6 ml of phthalic acid (10% in methanol)

615ml methanol, '.

applied. The drying temperature is 110 ⁰ C for a period of two minutes. The subbed substrate is conventionally coated with a lithographic emulsion (Sample A).

Example 2.

The procedure is as in Example 1, but on the adhesive layer A, an adhesive layer B (according to DD-PS 130286) of the following composition is applied:

3g gelatine 190ml water

9.0 ml of phthalic acid (10% in methanol) 9.0 ml of maleic acid (10% in water)

676ml methanol 18,0ml lithium chloride (2% in water) 9,3ml polymethyl methacrylate-methacrylic acid (20% in water) 9,0ml amine salt of a high molecular weight alkyl sulphate

3.1 ml of amine salt of a high molecular weight phosphoric acid ester (sample B)

Example 3

The procedure is as in Example 1, but on the adhesive layer A is an adhesive layer B, consisting of 4.2 g of gelatin 98 ml of water ·

9,6ml phthalic acid (10% in methanol) 615ml methanol 10ml Compound 1 (10% in methanol 3: 7), applied (Sample C).

Example 4

The procedure is as in Example 1, but on the adhesive layer A is an adhesive layer B, consisting of 4.2 g of gelatin 98 ml of water

8.0 ml 4% sodium hydroxide solution, - ''

615ml methanol '12ml Compound 2 (10% in WassenMethanol 3: 7), applied (Sample D).

Example 5

The procedure is as in Example 1, but on the adhesive layer A is an adhesive layer B, consisting of

4.2g gelatin 98ml water

9.6 ml phthalic acid (10% in methanol) 615 ml methanol

8ml Compound 3 (10% in water, methanol 3: 7) applied (Sample E).

The adhesion test with the dry film before the photographic processing, the edge peeling test and the adhesion test are carried out according to the described procedures.

Table 1

Quality level of dry adhesion

Grade of edge striping test

Checking the gluing tendency

Sample A Sample B Sample C Sample D Sample E

bad

D D A A A

As can be seen from the table, carrier materials can be obtained with the process according to the invention (Samples C, D, E) which, given good adhesion, have a strongly minimized sticking tendency. By contrast, comparative samples A and B stick together almost completely. In addition, there is the completely insufficient adhesive behavior of Sample B. The results of the determination of the extinction fluctuations as a measure of the surface quality of the substrate layers as a function of the film speeds are shown in Table 2. As a result, the samples C, D, E produced by the method according to the invention exhibit only a very small increase in the extinction fluctuations in the film speed range of 60 and 70 m / min. In contrast, samples A and B show a significant increase in extinction fluctuations from a speed of 50 m / min. The extinction variations = S 60 m / mim admitted for carrier material with excellent castability are thus only achieved in the case of the substrate according to the invention.

Table 2

Extinction fluctuations [%]

film speed 40 m / mm 50m / min 60 m / min 70 m / min = Wet layer thickness 45 / xm 36 jam 30 / to 26 / im Sample A 2.48 4.94 6.81 12.5 Sample B 1.01 · 2.55 4.78 8.97 Sample C 0.88 1.25 , 2.51 2.82 Sample D 0.98. 1.72 2.64 3.49. Sample E 0.94 1.51 2.60 3.05

The photographic parameters of the substrate formulations according to the invention (samples C, D, E) remain unchanged in comparison to the type (samples A, B).

Claims (1)

Invention claim: A process for the substrate of hydrophobic photographic support materials by one- or two-sided coating with an adhesive layer system consisting of one or more synthetic polymers containing adhesive layer (s) A and an adhesive layer B thereon based on a hydrophilic colloid, characterized in that the the surface-forming adhesive layer B in a concentration range of 5 to 30 wt .-%, based on the dry weight of the hydrophilic colloid, imidazolines of the general formulas