DE2162207A1 - Light-crosslinkable mass for relief-like recordings - Google Patents

Description

DR.-ING. BY KREISLER DR.-ING. BEAUTIFUL FOREST DR.-ING. TH. MEYER DR. FÜES DIPL-CHEM. ALEtCVON KRElSLER DIPL-CHEM. CAROLA KELLER DR.-ING. KLÖPSCH DIPL.-ING. SELTING

5 COLOGNE 1, DEICHMANNHAUS

Cologne, December 14th, 1971 Mr / Breu

EGG. du Pont de i-Temours & Company, Wilmington 19 898, Delaware / United States of America

Light-crosslinkable mass for relief-like records

The invention relates to a light-crosslinkable mass for relief-like Records from a photosensitive, uniform crosslinkable organic polymers.

It is known, light-crosslinkable compositions for relief-like Recordings ("photoresists") for use in coating solutions to manufacture. The usual technical processes for the production of relief images are used either with photoresist masses, de are applied as liquids, or in addition to the removal operation the resist mass. require one or more operations carried out in liquid form with liquids .

The most commonly used liquid photoresist measures contain dichromates, azo compounds, chäloon compounds or cinnamic acid esters adhered to or used in conjunction with polymeric binders. One already has Gelatin silver halide films proposed as photoresists, however, these are not rendered immediately insoluble during exposure and therefore require prior washing of the unexposed areas one or more im .feuchten State of process steps of a chemical nature to be carried out.

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The properties of the substances sensitized with dichromate, which are either applied in liquid form or used in the "carbon tissue process" vary largely with the moisture and can x ^ egen the Instability of the bichromates cannot be presensitized even in the absence of actinic radiation.

In U.S. Patent 3,526,504- are materials and Process described for making photoresists that do not require liquid sensitization or application processes require. These materials include a photo-crosslinkable layer that has low to moderate adhesive strength on a carrier film and which is covered with a protective film or a membrane. The latter is then removed and the layer is laminated onto the surface to be provided with the image and then exposed. After imagewise exposure, the unexposed areas of the layer are grounded, leaving one behind Washed out resist image. With the exception of the washing process, the process only runs in a dry state and does not require any action to be carried out in liquid form.

In general, these liquid or film resist compositions are used for etching copper images. To this For this purpose, the photoresist compound is applied to a suitable substrate, for example one coated with copper Board made of phenolic resin or epoxy resin, and through a Exposed transparently to actinic light. One serves Then a suitable developer process to apply the resist in the unexposed areas remove. The uncovered surface can then modified and processed in various ways will. So you can treat them with a suitable liquid reagent to form an etched surface, they can be coated with metal, anodized,

/ Ί. \ Η η? 7/1 0 3 3

coloring, coating or other treatment.

If the resist mass is used in the form of aqueous coating solutions, thus, a problem arises in that the cured film areas are removed from the aqueous coating solution be undercut. This affects from the fact that the resist is peeled off or lifted from the substrate. This phenomenon causes a diminished one Edge drawing of the original and is very undesirable. It was often necessary to have a large number of panels for this reason to be discarded as unusable.

The invention is based on the object of providing a light-crosslinkable, resist-forming mass which is characterized by characterized by a special adhesive strength, so öaß one Undercut and accordingly a separation or Lifting of the hardened image areas from the substrate is not to be feared.

The invention is based on a light-crosslinkable mass for relief-like recordings from a light-sensitive, Uniformly crosslinkable, organic polymer that, when activated by light, is used for every chemical process cannot form more than one cross-link and is not capable of linear addition polymerization is. It is characteristic that the mass contains a small amount of a heterocyclic, nitrogen-containing compound the formula. . ,

.Nc- '

contains, wherein R represents an ortho-aromatic hydrocarbon ring, while X · for CH _? , KH, S, O or Se and Z stands for N or CI, where Y equals'H, -KH ^, a

r.- ij 2 7/1 0 3 3

- Zj. _

Alkyl radical with 1 to 4 carbon atoms or one Halogen, e.g., chlorine or bromine. Lie.lichtvernetzbar e mass can, as in US Pat. No. 3,526,504 described, applied to a layer support, exposed and be treated further.

In the context of the frerocyclic in question for the invention Nitrogen-containing compounds have been granted the following in particular: Benzotriazole, 1-C * chlorobenzotriazole, Benzimidazole, 2-methylbenzimidazole, 5-methylbenzimidazole, 2-aminobenzimidazoi, 5-nitrobenzimidazo! and 2-aminobenzothiazOl.

To the. Suitable photo-crosslinkable compositions include photodimerizable substances such as cinnamic acid esters of high molecular weight polyhydric alcohols, polymers with residues of the chalcone and benzophenone type, or other substances described in Chapter 4 of the book "Light Sensitive Systems" by Jaromir Kosar (John Wiley & Sons, Inc ., Hew York). With or without additional sensitizers, under the influence of actinic radiation, these compounds form both directly crosslinks and materials of high molecular weight which can form crosslinks via particular light-sensitive types. This latter group includes high molecular weight substances such as polyacrylic acid and polymethacrylic acid amides and their derivatives, polymeric polyhydric alcohols, natural colloids such as gelatin, glue, shellac in combination with light-sensitive crosslinking agents such as the azo compounds, azides and, if the resist is immediate is applied, metal dichromates. Other suitable substances are described in Chapters 2, 6 and 7 in Kosar , (Ie). Information on suitable substances are also found in the US Patents 2,299,839 _r ^2379413, 2670286 and 3526 * 504th

209 0 27/103

If there are many light-crosslinkable materials, then no additional macromolecular binder required, however, thermoplastic, macromolecular, organic binders including those described in the United States patent can be used 2 760 863 can be applied. In addition, you can use plasticizers, colorants (dyes and pigments) and fillers according to the Use the information in this patent specification.

In practicing the invention, a light-crosslinkable mass, as described in the ÜSA ^ patent specification 3 526 5Ö4, are produced * During the Preparation of the photoresist composition then uses a small amount of the heterocyclic nitrogen containing compound added, examples: benzotriazoles 1-chlorobenzotriazole, Benzimidazole 2-Methylbenzimidazöl, 5 ~ Methylbenzimidazole, 5-nitrobenzimidazole, 2- * aminobenziraidazole, the corresponding 2- or 5-ethyl-, -propyl- and -n-butyl- * benzimidazole or 2-aminobenzothiaz oil. The one on the addition Improved adhesive strength resulting from these compounds can be achieved with as little as 0.05% by weight of nitrogen containing heterocyclic compound in the photo-crosslinkable Mass can be achieved. Higher proportions of these Connections can also be incorporated, but the upper limit for each individual compound is given by its solubility in the photoresist mass. First The blends of the invention show an essential line improved adhesion to copper substrates, though the adhesion of the film compound to other metal substrates in similarly can be improved * In addition, can these masses applied as liquids or as Films are laminated onto such substrates.

Preferred photocrosslinkable materials of the invention can be produced by using a solution or a

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Dispersion of the photo-crosslinkable, organic polymer) which contains one of the listed * nitrogen-containing heterocyclic compounds, is applied to a thin * flexible, smooth carrier film, in particular a layer carrier made of, for example, polyethylene terephthalate, and the layer dries by removing or evaporating volatile solvents or diluents, and, if desired, a protective cover sheet or a cover film *, for example one made of polyethylene, is applied to the layer. The layer support is preferably transparent to actinous radiation, has good strength and dimensional stability in the event of temperature changes and withstands the dissolving action of conventional solvents. The carrier film is so.'auszuwählen that ^l it can be pulled off easily in the dry state of the layer of lichtvernetzbar s, organic POLYMEX ^v s. The photo-crosslinkable layer preferably has a thickness of 0.013 to 0.076 mm or more, while the support and the protective film are used with a thickness of 0.006 to 0.13 rom or more.

If a protective film is used, this should be a * - have more adhesive strength on the layer than the carrier has * This protective film or protective film can be applied by pressing or lamination, for example by coating the film and the light-crosslinkable material runs through rollers.

In a preferred embodiment of the irfiiidüng is an optionally applied protective film is first removed from the light-crosslinkable layer of the material and then this layer with the Eupfeiöberfiache one with Copper-coated epoxy resin furnace brought into contact, in particular, as described above, by pressing on or laminate on. The layer can then be on 'metal or

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other etchable surfaces and the removable, e Support film removed before or after exposure will.

The coated copper surface can now with a exposed a printed circuit having transparency which can be a procedural negative, or procedural positive. Describes suitable exposure methods U.S. Patent 3,526,504.

After exposure, the light-crosslinkable layer will be the unexposed areas with a suitable solvent, for example trichlorethylene, developed (removed). As the photo-crosslinkable mixtures of the invention on a sheet made of a resin or coated with copper a polymer have been applied, is the copper underlay exposed after this process step. Man ' then turns the photosensitive material into a cathode, for example in a copper pyrophosphate electroplating solution, and electroplated at cathodic for 30 minutes Current density of about 323 amps / m at one voltage of 1.5 volts. A metal insoluble in iron (HI) chloride, for example gold, becomes electrolytic via the deposited copper is plated and the crosslinked resist is then plated using a suitable solvent, For example, methylene chloride, deducted .. The beforehand by The resist covered areas are in a ferric (HI) chloride solution from 45 ° trees etched away while creating a gold-plated, deposited copper pattern of the printed circuit on the epoxy » resin board.

Such methods become advantageous in manufacture from . thick panels with a thickness of over 0.05 mm and printed circuit boards are used. Contained with the nitrogen

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the heterocyclic compound of the invention in the With the resist compound, there is no need for heat curing to be carried out after exposure in the plating process. One thing sticks during copper electroplating heterocyclic compound-containing resist more firmly on the copper-plated surface of the resin board than the resist not containing such a heterocyclic compound. .

The mixtures of the invention can also be used to manufacture Use of relief images and printing forms.

The following examples illustrate the invention.

example 1

A polyvinyl cinnamate was prepared in the manner described in U.S. Patent 2,670,286 incorporated into a coating compound of the following composition:

Polyvinyl cinnamate 2-t-butyl anthraquinone Methyl ethyl ketone

Then a second batch of the mixture described was made produced, but incorporated 0.05 g of benzotriazole became.

Both mixtures were transparent to 0.025 mm thick Films of polyethylene terephthalate applied with training a 0.0076 mm thick, dry layer. After drying, the surface of each layer was

2 on a piece of a clean, each m with 305 6 copper

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11 , 4 O , 6 120 , 0

coated board made of epoxy resin fiberglass laminated. using rollers heated to 120 °. The. Copper surfaces of both panels were rubbed with Sandpaper, buffing and thorough rinsing with water cleaned and then dried with the help of air jets. Each clamped in a yakuum frame, laminated Material was printed 9 min. With an an image of the; -Circuit bearing transparency with ultraviolet light emitted by a mercury arc lamp operating at medium pressure was delivered, exposed. Distance: 66 cm. The transparent film was then exposed from each Layer peeled off and the exposed layers then developed by exposing them to the spray vapors of trichlorethylene for 30 seconds suspended. In this way the unexposed areas of the photoresist layers were removed underneath Leaving resist images that are suitable for a Copper plating was suitable. After developing were both Hesist tablets with water, rinsed and then in 25% sulfuric acid immersed, after which again ^ with Rinsed with water and a rinse in 25% ammonium persulfate solution (25 sec.) Has been connected. This was followed by another rinse with water and immersion (20 sec.) In 25? 6% sulfuric acid, after which, finally, was still rinsed with distilled water.

Each Resisti Eupfert sheet was then placed in a plating bath laid from copper pyrophosphate of the following composition:

Copper (Cu ⁺² ) 30 g / l

Pyrophosphate (P ₂ O ₇ "" ^) 200 g / l Nitrate (NO ₅ ") 8 g / l

Ammonia (Ii] H _x ) 2 g / l

ortho-phosphate (HPp ^) 0.1 g / l

Weight ratio pyrophosphate: copper = 7 * 5 *

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This treatment bath was maintained at a pH value of 8.2 and a temperature of 50 ⁰ C. The bath operated at 1.5 volts and a cathodic current density of 323 amperes / m *. Copper was deposited in an electroplating bath for 15 min Bathed and then allowed to air dry. The resist samples containing no benzotraizole showed bubbles and tended to "lift off the board during the electrodeposition of copper.

The electrolytically deposited on each resist board Copper was then combined with a metal such as gold. overplated, which dissolves in iron (III) chloride solution- borrowed, after which the resist using methylene chloride was withdrawn. Both panels were etched in a 45 ° Baume ferric chloride solution and formed panels after the pattern of plated printed circuit boards gen out.

Example 2

According to Example 1, two compounds for printed circuit boards were produced, applied, exposed and developed and electroplated. The adhesion strength of each resist film on the copper board was determined in the following manner tested: a 7.62 cm wide strip was placed on each panel applied to a cellophane adhesive film and then torn off. The amount of resist left on the adhesive sheet .ist proportional to the deterioration of the resist in the bath. on the cellophane tape stuck a lot more film mass, though the sample contained no benzotraizole as on the benzotnazole containing sample, resulting in improved resist-to-copper adhesion is occupied if the heterocyclic nitrogen-containing compound is present.

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Example 3

Polyvinyl acetophenone was prepared as follows: 11.8 g of acetyl chloride were added to a continuously stirred suspension of 26.8 g of finely divided, anhydrous aluminum chloride in 100 ml of tetrachloroethane; then a solution of 10,4- was g of polystyrene (molecular weight: about 4-00 Melting point "75 ⁰ C).. eye inserts in 100 ml Tetrachloräthaa, with hydrochloric acid developed The Reaktionsmisehung was 2 h stirred, filtered, and the finely divided. treated residue was dried in air and then for 10 min. with cold 5% hydrochloric acid, the polymer was (collected by filtration and washed several times with cold water. the substance obtained (12 g) was reacted with anisaldehyde according to example 3 of the US Patent 2 716 097 condensed with the formation of polyvinyl anisylacetophenone.

Then, a resist composition of the following composition was made manufactured:

Polyvinyl anisylacetophenone 8.5

Triethylene glycol diacetate 1.0

4-, 4- '-bis- [Dimethylamine] -benzophenone 0.5

Methyl ethyl ketone 40.0 |

An additional batch of the above composition was made, but contained 0.02 g of benzotriazole.

Each mixture T & rde then, as described in Example 1, stacked on a copper-coated spoxy resin fiberglass board laminated, exposed, developed and electrolytically electroplated with copper and then with gold, with the exception that 2 min. with actinic Light was exposed. The resist samples without incorporated Benzotriazole became vesicular and tended during the

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electrodeposition of copper to lift off the blackboard. Both samples were tested in accordance with Example 2 with regard to the adhesive strength. The benzo, The triazole-containing sample clearly showed improved adhesion of the resist to the copper-clad board in the plating of copper and gold when compared to the non-benzotriazole sample.

■ Example 4 ■

It became an allylic one. SOtoresistmasse according to Example 1 of the USA ~ ^p atentschrift 3462267 produced had the following composition ^:

Diallyl isophthalate prepolymer 12.0 S. Xylene 55.0 G 4-methoxy-4-methyl-pentanone-2 33.0 S. Benzil 0.1 S. 4,4'-bis [dimethylamino] benzophenone 0.1 G Xanthone 0.4 G Methyl ethyl ketone 25.0 G

A similar composition was prepared as indicated above, except that 0.2 g of benzotriazole was incorporated.

Both masses were drawn up as described in Example 1, laminated onto a copper-coated epoxy resin glass fiber board, exposed, developed, with copper and then electroplated with gold except that exposure to actinic radiation was 1 min.

Both samples were found to be equivalent in terms of adhesive strength Example 2 tested. The sample containing benzotriazole showed significantly improved bond strength of the resist on the copper-clad board during plating with copper metal, compared to the sample that had no Benzotriazole contained.

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Example ^

Corresponding to Example 1 of US Pat. No. 2,379,413 became a polyamide resin made from the methyl ester of linolenic acid and ethylenediamine.

An aqueous solution of disodium ^^ '- diazidostilbene-2,2'-disulfonate was prepared as follows: M- g 4,4'- -diaminostilbene-2,2'-disulfonic acid and 5 nil concentrated hydrochloric acid in 80 ml of water were added Cooled to 0 to 5 ° C, 1.5 g of sodium nitrite in 25 ml of water were added dropwise and the mixture was stirred for one hour. 1.3 g of sodium acid in 25 ml of water were then added to the solution, which had been kept at 0. After the evolution of nitrogen had ceased, the solution was stirred for 1 hour and filtered in order to remove finely divided impurities.

10 ml of the aqueous solution of disodium 4,4'-diazidostilbene were added to the refluxed solution of 10 g of polyamide resin in 100 ml of isopropanol. The received Dispersion was purified by cast coating onto a copper-coated one according to Example 1 Epoxy fiberglass panel applied. When dry the applied layer was approximately 0.010 mm thick. Another approach to the mixture described, but an additional one Containing 0.05 g of benzotriazole was applied in the same manner to a copper-coated epoxy-fiberglass board upset.

Each panel was exposed as in Example 1 and the underexposed areas by brushing with isopropanol washed out. Each resist-bearing panel was then cleaned according to Example 1 and copper-plated for 20 minutes. The resist containing no benzotriazole was completely removed from the electrolytic copper deposition copper-coated surface peeled off. The benzotriazole containing Hesist adhered during the entire electrical

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21622Q7

plating of copper on top of the copper-plated Surface to produce a usable sheet of electrical circuit after gold plating and an etching according to Example 1 had been carried out.

Example 6 .

-It became a photosensitive resist composition as shown below • Composition prepared:

Polyvinyl alcohol (87 to 89 mol% hydrolyzed; viscosity of a 4% aqueous solution at 20 °: 35 to 45 GP) 8.5

Sodium borate 0.1

Ethylene glycol 1.0

Ammonium dichromate 0.4-

Water. 1 ^ύ / ο

A second approach of the same resist mass, but the one 0.1 g of benzotriazole was prepared.

Each mixture was made by pouring it onto one with copper coated epoxy resin fiberglass panel applied and how indicated in Example 5, dried, exposed and plat- · with the exception that the electrodeposition of the copper was terminated after 8 minutes.

read no resist containing benzotriazole became blistered and dissolved during the electrodeposition of copper completely from the copper-plated surface. In contrast, the resist containing benzotriazole remained Firmly on the copper-coated surface of the board during the entire electrolytic deposition process adhere and delivered a usable board printed scarf

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tung, after a subsequent gold plating and Etching according to Example 1 had been made.

Example 7

Analogously to Example 1, 5 batches of a polyvinyl cinnamate coating material were produced. Of these, one batch contained no heterocyclic nitrogen compound, while the other four batches each contained 0.05 g of one of the following compounds: \.

1-chlorobeiizotriaaol, |

Benzimidazole,
5-methylbene?, Imidazole,
2 ~ aminobenzothiazole.

The five mixtures were as indicated in Example 1 on layered, on copper-coated epoxy resin fiberglass panels laminated, exposed, developed and electroplated.

The samples containing the heterocyclic nitrogen-containing compounds of the invention remained during the Galvauisierumg with copper adhering firmly to the Copper surface of the panels, while the untreated sample drew bubbles and partially from the copper surface took off. In the adhesion test according to Example 1, the 1-chlorobenzotriazole, benzimidazole, Containing 5-methylbenzimidazole and 2-aminobenzothiazole Samples have a lower sticking to the cellophane tape Resist mass than the untreated sample.

Example 8

As in Example 3, four batches of a polyvinylanisylacetophenone resist mixture were used manufactured. One batch did not contain any heterogeneous nitrogen

■ ι η _

■ ■■ '"/i'iJ.,27/ 1 033

Compound of the invention, while the three remaining batches contained 0.02 g of one of the following compounds: 2-methylbenzimidazole, 2-aminobenzimidazole and 5-nitrobenzimidazole.

The four mixtures were applied as in Example 3, laminated onto copper-coated epoxy resin fiberglass panels, exposed, developed, electroplated and, as indicated in Example 1, etched. During the electroplating with copper, the resist containing no nitrogen-containing compound of the invention was blistered and partially peeled off from the copper surface. The mixtures containing 2-methylbenzimidazole, 2-aminobeiizimidazole and 5-nitrobenzimidazole adhered firmly and provided good printed copper circuits. When the sample WUX tested for the bonding strength in accordance with Example 2 ^ to, the invention containing sample was prepared by the Cellophanteststreifen more untreated resist composition removed as by ^ enes samples in which the resist treated with one of the heterocyclic compounds of the invention from which no nitrogen compound has been was.

m Example 9

The resist mixtures of Examples 1, 3, _5, 4, 7 and 8 were applied in liquid form with a cast coating according to Example 5 to copper-coated epoxy resin fiberglass panels and dried. The resist materials obtained were then exposed according to Example 1,. · Designed, electroplated and etched.

During the electroplating of the copper resist, the Mixtures in which the heterocyclic nitrogen compound was not present blistered and were partially peeled off. The resist mixtures, which the heterocyclic

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2 0 Π r, 7 1 I 1 0 3 3

Containing nitrogen compounds of the invention adhered during the electroplating of copper and gold the copper-plated surface. When checking on They showed improved adhesive strength according to Example 2 Liability when comparing with the resists free of these compounds.

- Example 10

As described in Example 4, resist mixtures were produced, applied, laminated, exposed and developed and electroplated with copper. A lead was then used over the galvanically deposited copper and lead-tin-fluoroboric acid baths containing tin (60 / 4-0 'parts by weight) when applying a current of 161.5 amperes / m for 15 minutes, a 60 / 4-0 lead tin-over eye is plated on. The resist was then removed with methylene chloride and the copper in ammonium persulfate as an etchant etched.

The resist containing no benzotriazole showed during. Electroplating of copper with lead and tin bubbles and tended to lift off the copper-plated base> • while the resist with benzotriazole adhered firmly to the copper base during electroplating with formation Eisr board with printed circuit with good edge drawing. ·

Example 11

As indicated in Example 4-, coating mixtures were made produced and applied with the exception that 1 g of poly (methyl methacrylate) with a molecular weight of about 40,000 was added prior to application of each mixture. After drying at room temperature, a 0.0063 mm thick polyethylene protective film on each coated light-crosslinkable layer laminated, whereby to 50 °

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-
4 *

heated pressure rollers were used. After 3 days the polyethylene protective films were peeled off, each photocrosslinkable Material is laminated to a copper-plated surface of an epoxy resin board and then coated, developed and electroplated with copper as in Example 1. Both samples were made according to Example 2 tested for adhesive strength, the benzotriazole-containing sample having an improved adhesive strength of the sesist on the copper-plated panel showed when compared with that * sample which did not contain benzotriazole.

Claims (2)

PATENT LAWYERS DR.-ING. BY KREISLER DR.-ING. SCHDNWALD 2162207 DR.-ING. TH. MEYER DR. FUJES DIPL-CHEM. ALEK OF KREISLE * DIPL-CHEM. CAROLA KELLER DR.-ING. KLÖPSCH DIPL-ING. SELTING 5 COLOGNE 1, DEICHMANNHAUS patent claims Ί) Light fusible mass for relief-like recordings made of a light-sensitive, uniformly crosslinkable, organic polymer that, when activated by For every chemical process, light cannot form more than a cross-connection and not a linear one Addition polymerization is capable, characterized in that the mass contains a small amount of a heterocyclic, nitrogen-containing compound of the formula where R is an ortho-aromatic hydrocarbon ring, while X is CH ₂ , M ₁ S, O or Se and Z is N or CX, where Y is H, KHo _{1 is} an alkyl radical having 1 to 4 carbon atoms or halogen . 2.) Light- _{crosslinkable composition according to claim I 1,} characterized in that the nitrogen-containing compound is present in the composition in an amount of at least 0.05% by weight. ■, 5.) light-crosslinkable composition according to claim 1 and 2, characterized characterized in that it contains a thermoplastic, macromolecular, organic polymeric binder. 4.) Light-crosslinkable mass according to claim 1 to 3, characterized characterized in that the nitrogen containing compound is benzimidazole or benzotriazole. 2 Μ 3? 3 27/1033 5.) Light-crosslinkable that forms relief-like records Material, characterized in that it consists of a layer support with an applied layer according to claim 1 to 4 consists. 6.) Material according to claim 5, characterized in that that the support made of polyethylene terephthalate or a plate made of natural or covered with copper synthetic resin and is preferably transparent to actinic radiation. 7.) Material according to claim 5 and 6, characterized in that that on a surface of the layer with the photo-crosslinkable mass, a flexible base film from a polymer, in particular polyalkylene terephthalate, has been applied which transmits actinic radiation and which adheres only slightly or moderately to the layer, while less adhering to the other surface of the layer Adhesion a more uniform, thinner, with application of pressure applied, non-illustrated protective film., in particular made of polyethylene or polypropylene, has been lit on ge br etc. 2 Ο Γ · "■ 7 7/1033 SAD ORIGINAL