DE2007524A1 - Photosensitive materials - Google Patents

Description

AG FA-G EVAERT AG

PATENT DEPARTMENT ΝΘ

za-mka Leverkusen

photosensitive materials

The invention relates to photosensitive materials which contain bis-pyridinium compounds as photosensitive substances, which transform into dark colored substances when exposed to power.

Numerous methods are known in which photosensitive organic substances are used for image recording will. Some of these processes are based on photochemical rearrangements or conversions of organic compounds, " which result in a color change. Such photochemical reactions of organic compounds have been summarized, e.g. in "Preparative organic photochemistry" (A. Schönberg, Springer-Verlag 1958) and "light-sensitive systems" (J. Kosar, John Wiley and Sons, New York, 1965).

This includes, for example, the formation of monomethine dyes Photolysis of trihalomethyl compounds in UV light in the presence of such aromatic or heterocyclic compounds Compounds which, due to their constitution, are suitable for condensation

10983S / U02

or diazo coupling particularly reactive GH ring members own.

In this process, the layers are sensitive to light from the start or the reaction components for the photochemical reaction must be added before exposure. The systems known hitherto are of limited practical use, since their photosensitivity in general too low -is.

The French already represent a certain improvement Photosensitive described in U.S. Patent 1,526,496 Materials represent. These materials contain cyclic imides of aryl polycarboxylic acids, their imide nitrogen through olefinically unsaturated linear or cyclic aliphatic groups is substituted.

The last-mentioned substances also do not quite meet the requirements of practice with regard to photosensitivity. They are also not usable for special recording materials desired for computers and oscilloscopes, of which not only a relatively high light sensitivity is required , but in which the imaging reaction should also be reversible, i.e. the image formed should be erasable again , so that the Recording material can be reused.

The invention is based on the object of developing light-sensitive, silver halide-free materials which have sufficient light sensitivity and which give sufficiently deeply colored reaction products.

Another object of the invention is the production of photographic recording materials in which the image formed during exposure can be erased spontaneously or by additional measures so that the material can be used again .

A-O 608 - 2 -

10983S / U02

2 O O 7 b 2 4

It has now been found that photographic materials are suitable for imaging which contain light-sensitive phenylboranates and bis- pyridinium salts.

Suitable compounds are characterized by the following formulas:

R_N '"yf ^ ti = Uiij-c« - R (anion) ₀

τ Ι τ '©

R ¹ BR cation

R ¹¹
where mean:

R = (I) an aliphatic group with up to 18 carbon atoms, preferably up to 5 carbon atoms, which can be saturated or unsaturated and which can contain further substituents, e.g. Phenyl, halogen, e.g. fluorine, chlorine or bromine, hydroxyl, it being possible for the hydroxyl group to be esterified, in particular with short-chain aliphatic carboxylic acids with up to 6 carbon atoms, carboxyl, esterified carboxyl, with the ester component in particular short-chain aliphatic alcohols are suitable, acyl, in particular acyl radicals, which differ from derive short-chain aliphatic carboxylic acids, sulfonamide, the amide group of which can be substituted with alkyl, Aryl, especially phenyl, acyl, which is preferably derived from short-chain aliphatic carboxylic acids or benzene carboxylic acids or another sulfonamide group,

A-G 608 - 3 -

109835 / U02

f 2ÜÜ7524

(II) cycloalkyl e.g. cyclopentyl or cyclohexyl or

(III) aryl, in particular a radical from the phenyl or naphthyl series, it being possible for this radical to be substituted similarly to the aliphatic radical under (I);

R = aryl, such as phenyl or naphthyl, in particular a radical from the phenyl series, it being possible for these rings to be connected to one another and for this radical to be able to carry further substituents, for example alkyl with preferably up to 5 carbon atoms, halogen such as chlorine or bromine, hydroxy , Alkoxy, carboxyl, esterified carboxyl, nitro, nitrile, carboxyl, esterified carboxyl, carbamoyl, sulfonic acid, sulfonamide or sulfonic acid ester groups;

R ¹¹ = nitrile or R ¹ ;

η = 0 or 1.

The nature of the anion or cation is not critical. It will depend essentially on the type of manufacturing process for the above components. Possible anions are, for example, halogen ions, in particular chloride or bromide, sulfate ions, sulfonic acid ions such as toluenesulfonic acid, sulfonate ions, for example methyl sulfonate, among others.

Depending on the pH of the solution of the component mixture or the layer, hydrogen or cations of the alkali metals are suitable as cations. Of course, cations of the alkaline earth series or ammonium ions, which can carry organic substituents, can also be used. The only decisive factor for the photosensitivity of the material according to the invention is the simultaneous presence of bis-pyridinium ions and phenylboranate ions.

Suitable are, for example:

109835 / -Λ02

Bis-pyridinumcations:

Η, σ -

- CH ₃ 2 Cl "

/Λ.ΟΗ, J

T-CH ₂ - // \\ 2 Cl "

H ₅ C ₂ -N 'V) -CH = CH- (/ \ N-C ₂ H ₅ 2 tosylate

Phenylborate :.

11.1

C ₆ H ₄ CH ₃ Na

11.2

-B C

^G 6 ^H 5 _ Na ¹

A-G

109835 / U02

^C 6 ^H 5

NC BC ₆ H ₅

Li

The above compounds are prepared according to known methods. Reference is made, for example, with regard to the Bls-pyridinium compounds to the publication by E. Weitz, Zeitschrift for Ang. Chemie 1954, pp. 657 ff. and with regard to the phenylboranates to the publication by G. Wittig, Ann. 563 (1949) p. II4.

The bis-pyridinium compounds and the phenylboranates need not be present in the light-sensitive material in a stoichiometric amount. It is sufficient if one of the components is present in an amount of about 10-90% by weight of the total weight of the components. A C _e is preferably halt of about 40 - 60 wt -i ° on one of the compounds in the mixture of compounds..

The pnotochemical conversion of the compounds mentioned goes both in solution and in the solid phase in front of you. For practical implementation, these substances are used individually, in a mixture or mixtures of several bis-pyridinium compounds or phenylboranates, dissolved or finely divided, with or without a binder applied to any substrate. The substances are applied using known methods Application or spraying of solutions or by pouring from solutions or suspensions with layer-forming natural Colloids or plastics. Gelatine, cellulose, Cellulose esters, cellulose ethers, polycarbonates, in particular based on bis-phenylolalkanes, polyesters, inabe-

A-G 608

1 0 9 8 3 5 * 7 1 night) 2

-Jm ..

iUU7b2A

special on the basis of polyethylene terephthalate, polyamides, polyurethanes and a wide variety of film-forming polymers or copolymers of olefinically unsaturated monomers, such as vinyl chloride, vinyl acetate, styrene, olefinically unsaturated monomers Carboxylic acids, their esters or other derivatives, such as maleic anhydride, acrylic acid or methacrylic acid and their derivatives, also polyethylene or polyvinylidene chloride, e.g. in the form of their aqueous dispersions.

The bis-pyridinium compounds can also be used in a separate Layer are accommodated and the boron compounds in a second, with the former in contact, be present.

The usual materials are suitable as the support, e.g.

Paper, glass or natural or synthetic materials, f such as cellulose esters, in particular cellulose acetate or cellulose acetobutyrate, Polyesters, especially those based on polyethylene terephthalate, polycarbonates, in particular those derived from bic-phenylolalkanes, polystyrene or similar. The support can be transparent or contain figments such as titanium dioxide, barium sulfate, etc.

The surface of the substrate can be smooth or profiled

The substances to be used in the manner according to the invention can of course be added directly to the layer support will. In the case of a layer carrier made of paper, for example, a simple bathing of the carrier material in a solution of the anger components is sufficient.

The photosensitive to be used in the manner according to the invention Connections can also be used in self-supporting layers. Layer binders are also suitable for this of the type indicated above. The layer binder is in principle not critical and can easily be drawn from the abundance of known natural or synthetic, hydrophilic or hydrophobic layer-forming agents can be determined by simple test experiments.

A-G 608 - 7 -

109835 / U02

Solvents for the compounds to be used in the manner according to the invention are, for example, water, short-chain aliphatic Alcohols such as methanol or ethanol, acetone, dimethylformamide, etc. are suitable.

The concentration of the photosensitive substances in the binder can be varied within any limits. By changing the concentration as well as the order, the Gradation or the maximum density can be influenced. When using binders that swell in water, the pH can such as gelatine, can be varied within the limits within which the binding agent has not yet been changed too far - E.g. degradation of the gelatine - takes place. Preferably, the substances are used in amounts of $ 1-80, based on the dry Layer, used.

Casting aids, e.g. wetting agents or compounds to improve the mechanical properties, can also be added to the layers (e.g. hardening agents), can be added.

Dj e photosensitive used in materials according to the invention Compounds produce colored products on exposure, depending on the type of reacting components and the structure the photosensitive layer are stable for several hours to several days.

These products formed at the exposed areas can be stabilized by adding certain compounds, see above that they remain visible for a long time. For this purpose, hydroxyl-substituted aromatic compounds are, in particular those of the phenyl or naphthyl series are suitable, e.g., hydroquinone, pyrocatechol, naphthols and the like. The same effect is achieved with nitrogen-containing heterocyclic compounds, e.g. pyrrolidones, especially N-methylpyrrolidone, or acid amides, e.g. dimethylformamide,

A-G 608 - 8 -

109835/1402

There is a particular advantage of the layers according to the invention in the possibility of deleting the images created in it. This can be done in a very simple way by moistening the layers can be achieved with water. This allows corrections to be made to the image or the entire material in a simple manner can be regenerated quickly.

The decline of the colored image substance into the colorless light-sensitive one The initial shape can be accelerated by heating. The photosensitive material remains fully usable and can be re-exposed immediately after drying.

For these reasons, the materials of the present invention have particular ones Significance for those processes where the deletion of the image and reuse of the material is required. |

It is possible to fix the photographic images obtained in this way by making the compounds insensitive to radiation in the unexposed parts of the layer. This can take place, for example, through the action of reagents which react with one of the components to form stable, colorless products. A separation of exposed and unexposed parts in the layer is also possible by selectively dissolving out one component using suitable solvents.

The layers according to the invention are colored pale yellow to light yellow. They are sensitive to UV light and also to the long-wave range, so that in principle they can be exposed to normal artificial light. Nitraphotlamps, neon tubes or laser light are particularly useful for the pur- ification. The exposure time naturally depends on the intensity of the light source, the distance between the layer and the light source and the sensitivity of the respective layer. In general, exposure times of a few seconds to a few minutes are sufficient. It is also possible to accommodate the two salts in two layers so that they only form the photosensitive compound through diffusion. Of course, a protective layer can also be applied by pouring or gluing on, which means that the half-life of the image can be extended almost at will.

^A " ^{G 608} 10 9 8 3 5 / Ί I 0 ~ 2

BATH ORIGINAL

/! UU / b24

It is particularly surprising and advantageous that the layers according to the invention can be spectrally sensitized. The compounds commonly used in silver halide photography can be used as sensitizers. For example, cyanine dyes, xanthylium dyes, acridinium dyes or the like are suitable. The sensitizing dyes are added in amounts of about 1/500 to 1 / 10,000 of the weight of the phenylboranate ⁴ :.

example 1

The following solution is poured onto a substrate made of barytaised paper:

0.4 g of compound 11.2 are dissolved in 10 ml of water and mixed with 30 ml of 10% gelatin; to a solution of 0.45 g of compound 1.1 in 10 ml 7'asser at 40 ⁰ C, 20 ml of 10 $ aqueous gelatin solution and 10 ml of 10 $ aqueous solution of polyvinylpyrrolidone was added.

The layer thickness of the dried layer is 16 μm. It is exposed imagewise with a nitraphot lamp at a distance of 10 cm for 2 minutes. You get a deep blue Image on the pale yellowish layer.

The picture can be kept for several hours, after a few layers it is completely gone. It can also be made to disappear in seconds by moistening it with water. After this Drying makes the layer sensitive to light again.

Example 2

If you add 1 g of hydroquinone dissolved in 10 ml of water to the casting solution for the above layer instead of the polyvinylpyrrolidone, a deep blue image is obtained with further appropriate processing, which is much longer lasting - about two days. Is poured with a protective layer # 5 gelatin strength on this photosensitive layer, the image is stable for over a week.

A-Q 608 - 10 -

109835/1402

BATH ORIGINAL

2 U U V b 2 A

The top layer can be spectrally sensitized. Puts for example, 0.01 g of 5,6-benzo-benzothiazole purple is dissolved in the casting solution in 10 ml of methanol, a pale pink layer is obtained which is sensitive to green light. The exposure time is 30 seconds for a halogen lamp. The distance from the light source was also 10 cm. The pale pink colored layer turns violet on exposure.

Sensitization to red light is achieved by adding it of 0.001 g of pinacyanol to the above casting solution. It is exposed to a halogen lamp for 45 seconds. You get a deep blue negative image of the original.

Example 3

The following is applied to a substrate made of barytaised paper Potted solution:

0.85 g of the compound 11.2 in 50 ml of 5 ^ iger aqueous Gelatin dissolved and added to a solution of 1.2 g of the compound 1.2 in 50 ml 5% aqueous gelatin with vigorous stirring admitted.

A light yellow layer is obtained. With the same further processing As in example 1, a red-violet negative image of the original is produced on exposure to a nitraphot lamp.

Example 4

The following is applied to a substrate made of barytaised paper Poured casting solution:

0.85 g of compound 11.2 in 50 ml of 5 # aqueous Gelatin dissolved and mixed with a solution of 1.6 g of the compound 1.3 in 50 ml of 5 fig. Aqueous gelatin and 1 g Polyvinylpyrrolidone added.

A-G 608 - 11 -

1 0 9 8 3 5 / U 0 2 ^ ₀ ORIGINAL

A light yellow colored layer is obtained which changes upon exposure as described in Example 1, it colors red-violet.

Example 5

The following is applied to a substrate made of barytaised paper Poured casting solution:

0.85 g of compound 11.2 dissolved in 5o ml of 5% aqueous Gelatin is poured into a solution of 0.9 g of the compound 1.1 with stirring and 1 ml of m-cresol is added.

Processing is then carried out as described in Example 1. A blue-violet negative image of the original is obtained.

If the exposure is carried out at an elevated temperature, e.g. between 50 and 70 ° C, the discoloration is significantly darker or the exposure time can be reduced.

Example 6

The following pouring solution is poured onto a substrate made of barytaised paper:

0.85 g of the compound 11.2 dissolved in 50 ml of a 1 ^ igen aqueous Solution of sodium alginate are stirred into a solution of 0.9 g of the compound 1.1 also in aqueous Poured sodium alginate.

It is further processed as described in Example 1. A gray-purple image of the original is obtained. Dissolve the compound 1.1 in 50 ml of a 5 # aqueous Gelatin solution instead of the solution in the 50 ml of the sodium alginate solution, a purple-gray image of the template is obtained.

A-G 608 - 12 -

1 0983 5 / U 0 2

2ÜU / S24

Example 7 Jj'l

A solution is applied to a cellulose triacetate support of 0.67 g of the compound 1.1 in 50 ml of a 5% aqueous Gelatin solution containing 1 ml of polyvinylpyrrolidone and 1.5 ml of a 10% aqueous saponin solution applied. After this This first layer is dried on a solution of 0.75 g of the compound 11.2 in 50 ml of the 5 # gelatin solution, which contains 1 ml of polyvinylpyrrolidone and 1.5 ml of the saponin solution, applied. After complete drying, you have an almost colorless photosensitive material, which when exposed to light provides a dark blue image.

A-G 608 - 13 -

10 9 0 3 5/1402

Claims (2)

Patent claims: 1. Photographic light-sensitive material containing a light-sensitive combination of phenylboranates and bis-pyridinium salts. 2. Pho tographiGchea material according to claim 1, e-n ^ halt, end a photosensitive combination of the following formulas: R _ ir \) - | UH = GiJ- (Z ^X \ N - R (anion), / "' J _R i ^! 1 cation where mean: H = (I) an aliphatic group with up to 10 carbon atoms, {U) cycloalkyl,
(IEt) aryl; II = aryl or R ¹¹ = nitrll or aryl η -O or I A-G 608 - 14 - 1 Π 9 8 3 B / U Ο 2