DE2509342A1 - Process for the production of a layer containing an optical brightening agent - Google Patents

Description

Case 8-9314 / lLF 1064+

D # Rpi: · £ ■ -? P: .. -! ' ^! G. Γ-T - \ ρ F

GERMANY DIP; . ■ '■ -. '■'' ^: " "' - ■ - ^ .---! R

8 MONKS SO ■ ΪΛ AU hh K i; IC IS E HSTR. 45

Attorney file 25 751 k. March 1975

Process for the preparation of an optical brightening agent

containing layer.

It is often necessary that applied layers contain optical brightening agents and that the optical brightening agents remain in the layers after they have been subjected to various processing measures, for example immersion in a liquid. An example of such a coated layer is a layer of a photographic one Material that has an optical brightener. When making such a material, you usually use it water-soluble optical brightening agents to ensure compatibility with the aqueous silver halide emulsion used for coating to reach. The water-soluble optical

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- ir -

Lightening agents, however, are not very noun towards an applied emulsion layer, so that after exposure treatment of the material with aqueous photographic processing solutions and washing with water result in that a high proportion of the optical brightening agent from the applied layer is removed.

According to the method of the present invention, it is possible to give a layer applied in this way a water-insoluble optical To incorporate brightening agent, so that the optical brightening agent is incorporated essentially noun into the layer.

The invention therefore relates to a method for producing a layer containing an optical brightening agent a carrier material, which is characterized in that there is a water-insoluble lightening agent in at least one liquid α, β-unsaturated monomers dissolves the thus obtained Monomer preparation in water and in the presence of a dispersing agent polymerized to form a latex and then a layer that contains or consists of this latex, applies to the carrier material.

The layer material can be made by mixing the latex with a compatible colloid, for example Gelatin, mixed. The method according to the invention is special suitable for the production of optically brightened photographic material, the layer material in this case as well is made by blending the latex with a

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Compatible colloid mixed before it is applied in the form of a layer to the photographic support material.

The optical brightening agent can be liquid in a single Monomers or a mixture of two or more monomers are dissolved. But you can also after looking at the optical Has dissolved brightening agent in a monomer, at least one further monomer in which the optical brightening agent is soluble is mixed with the monomer in which the optical brightening agent was dissolved.

Suitable dispersants that support the formation of the latex, are anionic wetting agents, for example sulfonates or salts of sulfuric acid esters, each of which is either one higher molecular weight alkyl radical or a polyglycol radical.

The amount of optical brightening agent present in the applied layer can be within very wide limits,

9
for example from 10 to 100 mg / m of the applied layer.

The optical brightening agent used must of course be included in the Monomers or the monomer mixture be soluble. Suitable α, β-unsaturated monomers are, for example, vinyl monomers, Styrene, acrylic monomers, and substituted acrylic monomers such as methacrylic monomers. Examples of suitable vinyl monomers are vinyl acetate, vinyl chloride and vinyl monochloroacetate. Examples of suitable acrylic monomers are methyl acrylate, Ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate.

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Examples of suitable substituted acrylic monomers are methacrylic monomers such as methyl methacrylate and 2-hydroxypropyl methacrylate.

The optical to be used in the process according to the invention Lightening agents must be free from water-solubilizing acidic groups such as carboxylic acid groups and sulfonic acid groups. A number of different classes of optical brightening agents can be used, particularly those containing at least contain a heterocyclic five- or six-membered ring, for example an oxazole ring, a thiazole ring, an imidazole ring, a triazole ring, a pyrazole ring, a furan ring, a thiophene ring, a perdicarboxamide ring or a coumarin ring. Examples of optical brightening agents which are suitable for the process according to the invention are listed below 1. to 6. below:

1. Benzoxazole compounds

a) Benzoxazole compounds of the formula

σ>

in the

A, and A "each stand for a benzene nucleus which is in

the manner indicated by the bond lines

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is bonded to an oxazole ring and which, for example, by chlorine atoms or methyl groups and in particular alkyl groups with at least 4 carbon atoms can be substituted,

B, represents a bridge link that conjugates an uninterrupted chain with the oxazole rings Forms double bonds and, for example, a remainder of the formulas

(2) - CH = CH-,

_ / "\ _ CH = CH

/ V CH - CH -TV

or especially doir formula

MU <■

I!

CH

means,
b) Benzoxazole compounds of the formula

HC CH

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in the

A one in the indicated by the bond lines Way to the oxazole ring bonded benzene nucleus, which may optionally be further substituted, and

R denotes an optionally substituted benzene nucleus.

2. Benzimidazole compounds

a) Benzimidazole compounds of the formula

- Bo - c; ι a

(4)

'2 - \ X ^A 2

R ₂

in the

A, and Ay each represent an optionally substituted benzene nucleus which is bonded to an imidazole ring in the manner indicated by the bond line,

B “a pontic that connects to the imidazole rings forms an uninterrupted chain of conjugated double bonds and, for example, one Rest of the formulas

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(5) - CH = CH -

CH - CH- _or .

HC CH

Il Il

■ -c cer

represents, and R ₁ and R "hydrogen atoms or substituents,

for example alkyl groups, hydroxyalkyl groups or ÄraIky! groups, mean.

b) Benzimidazole compounds of the formula

in the

A is an optionally substituted one in which by

the bond lines indicated way to the

Imidazole ring bonded benzene nucleus, R "an optionally substituted stilbene radical,

which is bound in the 4-position to the imidazole ring

is or an optionally substituted,

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- ίΤ -

5-phenylthiophene radical bonded to the imidazole ring in the 2-position and

R, a hydrogen atom or a substituent, for example an alkyl group, a hydroxyalkyl group or an aralkyl group.

3. Pyx * azoline compounds of the formula

«2

ü!

m the

R ₁ . a hydrogen breath _; a halogen atom, for example a chlorine atom, or an alkyl group, for example a methyl group, and

R3 is a carboxylic acid / kyiester group, for example a carboxylic acid emetliy! ester group, or a Mean sulfonic acid amide group.

4. Coumarin Compounds

a) 7-Triazinylaminocoumarin compounds of the formula

^R 8

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in the

Rj and R ^ similar or different

Substituents, for example chlorine atoms, HpN groups, residues primary or secondary Amines or alkoxy groups, in particular Methoxy groups and

Rg an optionally substituted benzene nucleus or an optionally substituted one, for example substituted by a halogen atom Mean pyrazolyl ring.

b) 2-triazinylaminocoumarin compounds of the formula

in the

R ₇ and R _{0 have} the meanings given above under a)

/ O

sit and

R _{1 represents} a hydrogen atom or a substituent.

c) 7-pyrazolylcoumarin compounds of the formula

in j CT HC * N -ΚΛο I. R ₁₂ 0 509 837 / 949

- TO -

in the

Rn has the meanings given above under a) owns and

R ..-. and R-J2, which can be the same or different and hydrogen atoms, alkyl groups, for example methyl groups, or aryl radicals, for example phenyl radicals.

5. Stilbene triazole compounds of the formula

fV CH = (H)

in the

R ₁ O is a hydrogen atom, a halogen atom,

for example a chlorine atom, or a low molecular weight alkyl group, for example a methyl group, and

R ₁ , a cyano group, an alkyl carboxylate

group, for example a carboxylic acid methyl ester group, a carboxamide group or sulfonic acid amide group attached to the nitrogen atom can be further substituted, mean.

- 10 -

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6. Distryrylbenzene compounds of the formula

in the

R ^ ₁ . and R, r>, which can be identical or different, mean low molecular weight alkyl groups, for example methyl groups, alkoxy groups, for example methoxy groups, gyan groups or carboxylic acid alkoxy groups.

As already mentioned, the method according to the invention is be? especially suitable for the production of photographic sm Material (i.e. a material that has a photosensitive layer), so that a preferred embodiment the invention is directed to a process for the production of a photographic material having a layer, which contains an optical brightening agent and which is characterized in that it is a water-insoluble optical Lightening agent in a liquid oc, ß-unsaturated monomer or a mixture of such monomers dissolves the monomer or mixture of monomers in water to form a latex polymerized and the latex applied in the form of a layer on a photographic support material or the latex with mixed with a compatible colloid and applied the mixture in the form of a layer to a photographic support material,

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In this embodiment of the invention it is more convenient to mix the latex with a compatible colloid, preferably gelatin, and then this mixture in the form of a To apply layer to a photographic base material. This gelatin can be a photographic emulsion and thus a light-sensitive silver halide or several light-sensitive silver halides as well as the usual additives, normally found in photographic emulsions are, for example, stabilizers, antifoggants, chemical sensitizers and optical sensitizers Dyes. In this case, the layer containing the optical brightening agent is one photographic silver halide emulsion layer. In other Gelatin, which essentially contains no additives, can be used, in which case that from the latex and the coated layer consisting of gelatin in the photographic material as a subbing layer therebetween the photographic carrier material and one overlying it photographic layer or several overlying photographic layers can be present. It can also as an intermediate layer between two light-sensitive layers present or can be present as a top layer on at least one light-sensitive layer.

It has been shown that the polymer latex in the material produced by the process according to the invention is present, especially if the material is

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is a photographic material, not only as a means of introducing a water-insoluble optical brightening agent acts in a layer of the material, but also gives the layer favorable properties, for example a less tendency to form wrinkles.

Any material suitable for this purpose can be used as the photographic support material, for example Paper, paper coated with a thin layer of polyethylene or a plastic film made of, for example, cellulose triacetate, Cellulose acetate butyrate or polyethylene terephthalate or a glass plate.

The inventive method leads to a Increase in the effect of the optical brightening agent that only about a quarter of the amount of the agent is required is compared to the method which consists in incorporating a water-insoluble optical brightening agent into a photographic Material by incorporating the optical brightening agent in a water-miscible, volatile organic solvent dissolves this solution of a coating compound added, which is then applied, after which the solvent is allowed to evaporate, so that the optical brightening agent remains in the applied layer.

In British patents 1,064,137 and 1,324,255 processes for the production of optically brightened photographic materials with the aid of latices are described,

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the polymers and water-insoluble optical brighteners contain. In these known processes, however, the polymerization does not take place in the presence of the optical brightener.

example 1

Optical brightening agent A

Prepare a solution of an optical brightener in one Mixture of two «» ^ -unsaturated monomers by adding 30 g of the optical brightening agent A in a mixture of 1175 ml (inhibitor-free) butyl acrylate and 325 ml 2-hydroxypropyl methacrylate lost to form the solution A.

An aqueous medium is then prepared which contains 1500 ml of distilled water which has been boiled to remove the air and then ^{cooled to 80 °} C. and which is stirred. 0.75 g of sodium metabisulphite and 1.5 g of sodium persulphate are added. .

After 10 minutes you give the solutions A and B (the following is given) with the same speeds in the course, of 30 minutes to.

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Solution B:

Sodium persulfate 1.5 g

Sodium metabisulphite 0.75 g, water 1400 g

After adding half of solutions A and B, add two surface-active agents of the formula to solution A.

"0 CH-

o - ((JH ₂ -cH ₂ -o) ₅ r _Tir -ρ

- OM

18.2 g M = H 32 g M = Ka

For the polymerization, the mixture is stirred for 2 hours at 80 ^° C., after which a brief steam distillation is carried out in order to remove the remaining monomers. 1680 ml of the aqueous polymer latex (solids content 30%) are then added to 8800 g of an aqueous silver chlorobromide emulsion which contains 60% by weight of the normal amount of gelatin, so that a binder is obtained which contains 40 parts of the polymer per 60 parts of gelatin and which gives a coating weight of 28 mg of the optical brightening agent per square meter.

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The emulsion is then applied in the form of a layer to a subbed polyester carrier layer and dried

Example 2

7 V- CH = CH -f ~ \

Optical brightening agent B

A solution of an optical brightener is prepared in a mixture of two α, β-unsaturated monomers by adding 35 g of the optical brightening agent B dissolved in a mixture of 1000 ml of vinyl acetate and 420 ml of 2-ethylhexyl acrylate. This gives the solution A.

An aqueous medium is then prepared which contains 1000 ml of distilled water (and which has been boiled to remove the air) and which is then ^{cooled to 80 °} C. and slowly stirred. Then 0.75 g of sodium metabisulphite and 1.5 g of sodium persulphate are added and, after 10 minutes, solutions A and B (the latter being indicated below) are added over the course of 30 minutes at the same rate of addition. After half of the monomer has been added, 44 g of the surface-active agent of the formula are added

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^H 17 ^C 8

₈ -O-SO ₃ Na

to solution A.

Solution B: sodium allyloxyethyl sulfonate 75 g

Sodium metabisulphite 0.75 g

Sodium persulfate 1.5 g

Water 1325 ml.

The mixture is stirred during 4 hours at 80 ⁰ C, to effect the polymerization, after which the festive monomers removed by a brief steam distillation.

A barite mixture is then prepared by adding 1000 g of Blanc fixe (synthetic barium sulfate) to a solution of 37 g gelatin in 4000 ml water. The mixture obtained is mixed with 0.5 g of sodium hexametaphosphate as a dispersant and 0.1 g of chrome alum as a hardener. 154 ml of the mixture prepared in the above manner are then added to this baryta mixture aqueous latex containing 30% solids.

The baryta mixture containing the latex is then applied to a photographic paper substrate, after which the Baryta layer is dried and gives a coating which contains 37 mg of the optical brightening agent per square meter. A silver halide gelatine is applied to the baryta layer.

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emulsion applied in the form of a layer, after which this emulsion is dried.

Comparative experiments

CK = CH-

Optical brightener C

In order to show that in a material that has an inventive, having an optical brightening agent-containing layer, the optical brightening agent being essentially noun is connected to the layer, a strip of the photographic film material produced according to Example 1 is (Strip A) together with a strip of the photographic film material produced according to Example 2 (strip B) in examined a Harrison fluorimeter, then exposed, developed, fixed and subjected to a long washing process. After washing, the strips are again placed in the Harrison

Fluorimeter examined.

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ORiSiMA: - 1M3PECTED

For comparison purposes, following the procedure of Example 1, a strip of photographic material (strip C) with the difference that 40.0 g of the water-soluble optical brightening agent C are added to the aqueous coating mixture of the gelatin-silver halide emulsion and the latex are added to give a layer that is per square meter Contains 37 mg of the optical brightener.

Thus, the material of the strip C is not according to the invention Process made because the optical brightening agent was not present in the monomers before they were formed of the polymer latex were polymerized.

For comparison purposes, a strip of a photographic Material (strip D) produced by adding 130 g of the optical brightening agent A (used in Example 1) Dissolves in acetone and this solution becomes an aqueous gelatin silver ha Io gen id emulsion added, the emulsion in the form of a Layer is applied to a polyester carrier material and dries to a layer that per square meter 100 mg of the optical Contains lightening agent. Thus, the material of the strip D is also not produced by the method according to the invention, since there is no latex in the material. When examining strips A and B according to the invention and the results obtained for Comparative Strips C and D are shown in the following table.

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• - 20 table

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Initial reading Reading after Reading after of the fluorine xoeter Einsn 15- an e: m- minute wash hour occurrence Washing process Strip A 46 45 45 Strip B 38 38 37 Strip C 48 29 26th Strip D 45 45 44

The value of 26 given for strip C means that about half of what was originally present in the material optical brightener has been removed by the one hour washing process. In contrast, there is essentially no optical Lightening agent has been removed from strips A or B.

The value 45 given for strip D means that four times the amount of optical brightening agent D is required is to achieve the same fluorescence that is achieved when using the same optical brightening agent according to the invention incorporated into the material in accordance with procedures.

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Claims (15)

Claims ]). Process for the preparation of an optical brightening agent containing layer on a carrier material, characterized in that a water-insoluble, optical brightening agent in at least one liquid α, β-unsaturated monomers dissolved, the thus obtained Polymerized monomer preparation in water and in the presence of a dispersant to form a latex and then a layer containing or consisting of this latex is applied to the carrier material. 2. The method according to claim 1, characterized in that the latex is mixed with a compatible colloid and the mixture in the form of a layer on a carrier material applies. 3. The method according to claim 1, characterized in that the latex is applied in the form of a layer to a photographic support material. 4. The method according to claim 1, characterized in that the latex is mixed with a compatible colloid and applying the mixture in the form of a layer to a photographic support material. 5. The method according to any one of claims 1 to 4, characterized in that that the monomer preparation is polymerized in the presence of an anionic dispersant. 509837/0949 6. The method according to claim 5, characterized in that the monomer preparation in the presence of a sulfonate or a salt of a sulfonic acid ester, each either a higher molecular weight alkyl radical or a Contain polyglycol residue, polymerized. 7. The method according to any one of claims 1 to 4, characterized in that that a preparation is polymerized which contains at least one of the following monomers: Viny! Monomers, styrofoam monomers, acrylic monomers, methacrylic monomers. 8. The method according to any one of claims 1 to 7, characterized in that that the polymerization is carried out in the presence of a coumarin brightener. "9. The method according to any one of claims 1 to 7, characterized in that that the polymerization is carried out in the presence of a stilbene triazole brightener. 10. The method according to claim 8, characterized in that the polymerization in the presence of an optical brightening agent the formula H ₃ C- (CH ₂ ) ₃ -0 performs. 509837/0949 11 »The method according to claim 9, characterized in that the polymerization in the presence of the optical brightener of the formula carries out. 12. The method according to claim 4, characterized in that the latex containing the optical brightening agent mixed with gelatin before the mixture is applied in the form of a layer to a photographic support material applies. 13. The method according to claim 12, characterized in that the latex with a gelatin-silver halide emulsion mixed. 14. The method according to claim 12, characterized in that the latex is mixed with a gelatin preparation that is used for the formation of a substrate layer, a Interlayer or a top layer is suitable. 15. The method according to any one of claims 1 to 14, characterized characterized in that the carrier material with a 509837/0949 such amount of the coating preparation coated that per square meter of the coated carrier material 10 to 100 mg of the optical brightening agent are present. 509837/0949