DE2064380B2 - Photosensitive mixture - Google Patents

Description

The invention relates to a photosensitive mixture according to the preamble of claim I.

Positive-working mixtures and copier materials based on o-quinonediazides are in the Reproduction technology used on a large scale. These compounds become too in the light of decomposition converted into a five-membered carboxylic acid, which is more soluble in aqueous alkalis than the undecomposed one Link. Such copying layers can also be higher molecular compounds, in particular Condensation resins, add to improve their copying and printing properties, but is not known that these additives are included in the light reaction. The connections have that Disadvantages that they are not very photosensitive and that they are thermally unstable.

Other known positive working mixtures consist essentially of hexaaryldiimidazolylene and condensation resins. However, such copier materials result in printing plates with only less Efficiency.

From US-PS 28 92 712 are photodepolymerizable mixtures of polymers, for. B. polyacetals or polymethyl methacrylate, and photoinitiators, e.g. B. Benzoin compounds, known. In order to achieve sufficiently short exposure times, the Exposure carried out in the presence of a solvent for the depolymerization products. This is special in addition polymers of ethylenically unsaturated compounds required to achieve a reversible To avoid regression of the polymer. Even so, there are still relative to image generation long exposure times applied.

The object of the invention is to find a positive-working, light-sensitive mixture with high photosensitivity and good storage stability, which can be developed into copies with high mechanical strength.
The invention is based on a photosensitive mixture, the solubility of which is increased by exposure to light and which contains a polymer with acidic substituents and an initiator. The mixture according to the invention is characterized in that the initiator is an N-heterocyclic compound which at least

ίο a pyridine, pyrazine or dihydropyrazine ring and contains at least one benzene ring as a substituent or in fused form and on these rings optionally carries further non-photosensitive substituents.

π base body in the mixture according to the invention heterocyclic nitrogen compounds contained are preferably acridine, phenazine and 2,3-diphenylquinoxaline. The heterocyclic base bodies preferably carry substituents or fused benzene

2 »rings. Examples of suitable substituents are alkyl, Alkoxy, nitro, dimethylamino, acetylamino, phenoxy groups and halogen atoms.

Preferred substituents are alkoxy, especially methoxy groups. In detail, for. B. the

The following connections can be used successfully:

9-phenyl-acridine
9-p-methoxyphenyl acridine
9-p-hydroxyphenyl acridine
9-acetylamino-acridine
"'Benz (a) acridine

I O-methyl-bsnz (a) acridine
Benz (a) phenazine
9,10-dimethyl-benz (a) phenazine 9-methyl-benz (a) phenazine / IO-methyl-

benz (a) phenazine
9-methoxy-bcnz (a) phcnazin / 10-methoxy-

benz (a) phenazine
Dibenz (a, c) phenazine
1 l-methoxydibenz (a, c) phenazine dibenz (a, j) phenazine
Dibenz (f, h) pyrido (2,3-b) quinoxaline 6,4 ', 4 "-trimethoxy-2,3-diphynyl-quinoxaline 6-methoxy-2,3-diphenyl-quinoxaline 4- (4-methoxy- phcnyl) -2-phenyl-quinazoline ⁴ '6-chloro-4', 4 "-dimethoxy-2,3-diphenyl-

quinoxaline
6,7-dimethyl-4 ', 4 "-dimethoxy-2,3-diphynylquinoxaline

2,3-di-pyridyl- (2) -5-aza-quinoxaline '"2,3-bis- (4-methoxyphenyl) -5,6-dihydro-

pyrazine

2,5-bis- (2,4-dimethoxyphenyl) -pyrazine 2,3,5,6-tetrakis- (4-methoxyphenyl) -

pyrazine
'' 2,3-Diphenyl-5,6-dihydropyrazine

A large part of these compounds is already in the older DE-PS 20 27 467 and 20 39 861 as photoinitiators has been proposed for photopolymerizable mixtures. The effect described there consists in to stimulate certain monomers to polymerize under the action of light, the exposed Layer parts are hardened. In contrast, the mixtures according to the invention are based on the exposed areas more soluble. So far nothing is known about the mechanism of the reaction that takes place known.

Particularly preferred by the founding gc-

measured heterocyclic compounds used in the 9-substituted acridines, especially the 9-phenylacridine, the 4 \ 4 "-dimethoxy-2,3-diphenylquinoxaline and its derivatives substituted in the 6-position, in particular the 6-methoxy derivative.

With particular advantage, it is also possible to use compounds which are created by linking the aforementioned heterocyclic compounds with reactive side chains of a polymer are obtained.

The mixture of the invention can be used commercially in the form of a solution or dispersion, e.g. B. as so-called Copy varnish, are recovered, which the consumer himself on an individual carrier, z. B. to Etching of molded parts, for the production of copied circuits, stencils, signage or screen printing forms, applied and, after drying, exposed and developed into an imagewise distributed layer.

The mixture can in particular also be in the form of a solid, au! ' photopolymerizable on a support Layer as light-sensitive copying material for the production of printing forms, relief images, Etch protection layers, stencils, mats, screen printing forms, color proofing foils or single copies in the trade to be brought. An important application is the production of storable presensitizers Printing plates for flat, letterpress and gravure printing.

The mixtures according to the invention are distinguished by a high sensitivity to light and excellent thermal stability. They have the further advantage over diazo compounds that in the Copy layer no gaseous nitrogen is developed during exposure. They also enable the Production of positive relief images or letterpress forms. The high molecular weight polymers with light-sensitive heterocyclic Scitenketten have no tendency to crystallize and can therefore Copy loops can be added in relatively large proportions.

The photosensitive mixtures also contain a high molecular weight polymer, the unit with acidic Substituents, especially with carboxylic acid, phosphonic acid, Sulfonic acid or N-arylsulfonyl urethane groups in combination with other units. Copolymers with acrylic and Methacrylic acid ester ^

The polymers form the main part of the mixture (based on solids). The heterocyclic Compound is generally used in an amount of from 0.5 to 30, preferably from 5 to 15 parts by weight added per 100 parts by weight of polymer.

The mixtures can also contain dyes. Pigments, plasticizers, wetting agents and color formers added will. Such additives should preferably be chosen so that they do not affect the light reaction absorb necessary light.

If triphenylmethane or phenazine dyes are added to the layers, these dyes become bleached out the areas hit by the light, so that an immediately visible image is obtained.

Suitable plasticizers or wetting agents are, for. B,

Triethylene glycol, dibutyl phthalate,

Polyoxyethylene sorbitan fatty acid ester,

Polyoxyethylene ethyl ether,

p-NonyIphenolpolyglykoläther and

Poly waxes.

With these additives the flexibility of the layer can be increased adjust and regulate the development speed.

If the mixtures are to be applied to copper carriers, organic sulfur compounds, e.g. B. 2-mercapto-benzothiazole may be added.
> The mixtures are preferably used in the production of letterpress forms, relief images and offset printing forms. Bimetal and tri-metal printing forms, copied circuits, screen printing stencils and printing forms for gridless offset printing.

ίο If the mixture is in liquid form as a so-called Copy varnish stored and only immediately before use on the base, z. B. a screen printing support or a printed circuit board is to be applied, the layer components are in a suitable

r> Solvent or solvent mixture dissolved or dispersed. As solvents are alcohols, ketones, Esters, ethers, amides or hydrocarbons are suitable. Above all, the partial ethers become more polyvalent Alcohols, especially the glycols, are used.

. '»The solutions or dispersions can be used directly for the production of printing plates with advantage after their production applied to a suitable support and the products obtained as photosensitive Copy materials stored and in the

The same or similar solvents as for the production of the Copy varnishes are used. The application is made

z. B. by pouring, spraying or immersion.

As a support are z. B. zinc, copper,

κι aluminum, steel, polyester or acetate film or Polyamide, the surface of which can be pretreated if necessary.

If necessary, an adhesion-promoting intermediate layer is placed between the support and the light-sensitive layer.

i "i layer or an antihalation layer applied.

The copier layers exposed in the usual way are expediently made with organic solvents developed, / .. B. acetone. Methyl ethyl ketone. Ethylene glycol monoethyl ether. Trichlorethylene or glycerine,

JH which you can use water or acids, e.g. B. Sulfuric acid.

When the developed copy material is to serve as a printing form, the layer by heating to a higher temperature, for example above 180 ⁰ C, "can einge-

• i> burns "to the abrasion resistance and thus the To increase the number of copies.

The following examples describe embodiments of the invention. All percentages and proportions are, unless otherwise specified, than

> ii to understand amounts of weight. One part by weight (Gt.) corresponds to I g. if 1 ecm is selected as the volume part (Vt.).

example 1
η A coating solution becomes out

2.5 Gt. a methyl methacrylate / methacrylic acid copolymer with an average molecular weight of about 32,000 and an acid number of 137,

0.01 Gt. Supranol blue GL (C.1.50.335).
20.0 Gt. Ethylene glycol monoethyl ether

prepares and increasing amounts of 9-phenyl acridine and H'i to electrolytically roughened and hardened by anodizing 0.3 mm thick aluminum applied by spin-coating at 100 ⁰ C for 2 minutes dried.

The samples are then placed under a gray wedge, the wedge steps of which surround the exposure factor

distinguish lor 1,4, 2 minutes with a tube exposure device, which contains 13 fluorescent tubes of 40 W arranged on an area of 60 χ 60 cm, exposed.

Developed for 30 seconds with ethylene glycol monoethyl ether, of about 10% water and 10% conc. Contains sulfuric acid, and then with protective paint colored.

The results are as follows:

The light sensitivity increases with the initiator content. The following table I gives the number of full exposed d. H. completely removed wedge steps and in brackets after that the number of intermediate steps with different 9-phenyl-acridine content.

Table I. Table II

Gt. 9-pheny! -Acridine

Wedge steps

0.15
0.20
0.30
0.45
0.60
0.75

1-2

4-5

9-Ό

(1)

(1-2)

(1-2)

(2)

(4)

(4)

Example 2

A coating solution is made

2.5 Gt. of the polymer described in Example 1.

0.2 Gt. 9-phenyl-acridine,

0.01 Gt. Supranol blue GLund

20.0 Gt. Ethylene glycol monoethyl ether

prepared and applied by spin-coating to electrolytically roughened aluminum hardened by anodization, the oxide layer of which is 3 g / m ^{2 , and dried at 100 °} C. for 2 minutes. The dry layer weight is 5 g / m ² .

Then, as described in Example 1, exposure is carried out under a photographic positive original for removal the non-image areas developed for 15 seconds with acetone by immersion and with aqueous sodium metasilicate solution wiped over. Then it is rinsed with water, fixed with 1% phosphoric acid, Colored with protective paint and, if necessary, with aqueous gum arabic solution for preservation rubberized.

The offset printing form obtained in this way delivers at least 100,000 perfect ones on an offset printing machine Prints.

To improve the abrasion resistance, the offset printing form 10 minutes baked at 24O ⁰ C. The print run then increases to at least 200,000.

Example! 3

A 'coating solution is according to the example 1 prepares and for sensitization with 0.2 Gi. one Initiator offset as indicated below.

The exposure takes place according to example 1, the processing according to example 2.

The light sensitivities observed are given in Table I below! at:

initiator Wedge columns 6-chloro-4 \ 4 "-dimethoxy-2,3-
diphenyl quinoxaline 6 (2) 9-phenyl-acndine 5 (2) Benz (a) acridine 5 (2) Benz (a) phenazine 2 (2) 6,4 ', 4 "-trimethoxy-2,3-diphenyl-
quinoxaline 2 (2) 6-acetylamino4'-4 "-dimeihoxy-
2,3-diphenyl-quinoxaline 0 (3) Mixture of esters from naphthoquinone
(1,2) -diazid- (2) -5-sulfonic acid
and 2,3,4-trihydroxy-benzophenone 0 (0)

The known positive-working diazo compound used for comparison gives in the stated Amount of no picture even with a much longer exposure time.

Example 4
A coating solution is made

0.55 Gt. of the polymer described in Example 5.

0.70 Gt. the initiator specified below,

0.005Gt. of the phenazine color used in Example 1

fabric and
15.0 Gt. Ethylene glycol monoethyl ether

prepared and as in Example 1 applied to anodized aluminum and dried. The copy layer is exposed for 2 minutes under a gray wedge and 15 seconds with that given in Example 1 Developer developed. Then it is fixed with 1% phosphoric acid and colored with fat paint.

The initiator used is made by reacting a copolymer of methyl methacrylate and glycidyl acrylate with 6-carboxy-4 ', 4 "-dimethoxy-2,3-diphenylquinoxaline according to the US patent 34 18 295 specified procedure. The nitrogen content of the reaction product is 2.8%.

Example 5
A coating solution is made

2.5Gt. a methyl acrylate / methacrylic acid copolymer with an average molecular weight of about 30,000 and the acid number hl 157

0.2Gt. 9-phenyl-acridine,

0.1 Gt. Supranol blue GLund
20.0 Gt. Ethylene glycol monoethyl ether

prepared and spun onto anodized aluminum and dried. In a pallial experiment, the Copy layer with a 1-2 μm thick overcoat provided with polyvinyl alcohol and processed similarly. Exposure and development are done accordingly Example 1.

If one compares the photosensitivity of the two samples, this is the case with the latter, with which the Post-diffusion of the oxygen during the exposure is inhibited by the overcoat, which is 180% higher.

This effect is also used when using others

Example 6
A coating solution is made

2.5 Gt. a copolymer of methyl methacrylate and N- (p-toluenesulfonyl) carbamic acid (j3-methacryloxy) ethyl ester (65:35, acid number 60),

0.4 Gt. 9-phenyl-acridine,

0.004 Gt. Ethyl violet (CI. Basic Violet 4) and
20.0 Gt. Ethylene glycol monoethyl ether

prepared and spun onto 0.3 mm thick, anodized aluminum.

After drying, 4 minutes on a 5 KVV under a positive original or under a gray wedge Xenon point light lamp exposed and transmitted for 10 seconds Treatment with the developer specified in Example 1 developed. The quality of the received Image corresponds to that of the images described in Example 3.

Example 7

A coating solution is prepared in accordance with Example 2, but without dye, and adjusted to 125 μm thick, biaxially stretched polyester film with a hydrophilic adhesive layer accordingly DE-AS 12 28 414 is provided, centrifuged and dried.

Exposure and development correspond to Example 1.

This copy can be mounted in an offset duplicator and used to make prints will.

Example 8
A coating solution is made

2.5 Gt. Methyl methacrylate / acrylic acid copolymer with an average molecular weight of 60,000 and an acid number of 82,
0.25 Gt. Polyoxyethylene sorbitan monolaurate,
0.4 Gt. 9-phenyl-acridine,

0.01 Gt. of a phenazine dye according to Example 1 and
20.0 Gt. Ethylene glycol monoethyl ether

prepared and spun onto anodized aluminum and dried. The exposure is 2 minutes below a positive original or under a gray wedge according to Example 1, developed for 30 seconds Diving in trichlorethylene. Then it is fixed with 10% phosphoric acid and colored with fat paint. the The printing form is ready for printing.

Example 9
A coating solution is made

2.5 pbw of the polymer described in Example 1,

0.2 pbw of 9-phenyl-acridine,

0.75 Gt polyoxyethylene sorbitan monolaurate and

5.0 pbw of ethylene glycol monoethyl ether

prepares and poured onto a 0.3 mm thick aluminum sheet to. Most of the solvent is allowed to evaporate at room temperature and then dried at 100 ° C. for 3 hours.

To produce a relief image or a high-pressure form, the copying layer is used for 20 minutes exposed using the tube exposure device according to Example 1 under a photographic positive original and then developed for 5 minutes with the developer specified in Example 1 by brushing over.

The thickness of the copy layer is 0.43 mm, the washout depth 0.185 mm.

Instead of the polyethylene sorbitan monolaurate,

■> nen also Polyoxyäthylenziyläther, p-Nonylphenolpo-Is glycol ether or triethylene glycol can be used.

The resulting relief images are comparable in quality.

_{| (|} Example 10

A coating solution is prepared according to Example 2 and with 0.1 pbw. 2-mercapto-benzothiazole offset. Then it is spun onto a cleaned copper surface of a Cu / Al bimetal plate,

R> gently dried for 2 minutes at 100 ° C.

The exposure is 2 minutes under a positive original or under a gray wedge according to Example 1, then developed for 40 seconds with the developer specified in Example 1.

To produce a bimetal offset printing form, the exposed copper is etched with ferric chloride etched away within a minute, then wiped over with 1% phosphoric acid and then with Colored fat color.

B e i s ρ i e I 11

For the production of color proofing foils, four coating solutions are prepared according to Example 2, but instead of the dye used there stained as follows:

a) Yellow foil: 0.07 pbw. Fat yellow 3 g

(CI.12.700),

b) red foil: 0.08 Gt. Zapon real fire red B

(CI. Solvent Red 109),
^Jl c) blue foil: 0.01 pbw Ethyl violet

(CI. Basic Violet 4).

d) Black foil: 0.08 Gt. Fat black HB

(CI.26.150).

M) These solutions are each centrifuged onto a 37 μm thick, biaxially stretched Polyäthyientcrephthalatfoiic and dried as in Example 2. Then the layers are placed under the associated silver film color separations (3 minutes blue or red foil,

4 · -, 5 minutes yellow or black foil) exposed with a tube exposure device and 15 seconds each with the developer specified in Example 1 developed.

When the extracts are placed on top of one another, a

■ jo corresponds to the original of the silver film excerpts Duplicate.

Example 12
A coating solution is made

^D:> 2.5 pbw of the polymer described in Example 1. 0.2 pbw benz (a) acridine,
0.01 Gt Zaponechtfeuerrot B (CI. Solvent Red 109)

and
20.0 pbw of ethylene glycol monoethyl ether

prepares and on an aluminum / copper / chrome trimetal plate centrifuged and dried

Then, as in Example 1, exposure is carried out using a negative original and the one there specified developer developed for 30 seconds

The exposed chromium is etched away with a solution of 17.4% CaCl ₂ , 353% ZnCl ₂ , 2.1% HCl and 45.2% water within 7 minutes and then

the paint layer removed with alcohol. Finally it is wiped over with 1% phosphoric acid and with grease paint colored. The tri-metal plate is ready for printing.

Example 13

A coating solution is used to produce a zinc high-pressure form

2.5 Gt. of the polymer described in Example 1,

0.2 Gt. 4 ', 4 "-Dimethoxy-2,3-diphenylquinoxaline,

0.02 Gt. Ethyl violet (Cl. Basic Violet 4) and

20.0 Gt. Ethylene glycol monoethyl ether

prepared and applied to a cleaned one-step zinc etched plate by spin coating and dried.

It is exposed for 3 minutes with a tube exposure device according to Example!, Developed for 1 minute with the developer specified in Example 1.

Then the exposed zinc surface is etched with 6% nitric acid at room temperature for 6 minutes. The shape created in this way is suitable for quality letterpress printing.

Example 14
A coating solution is made

2.5 Gt. of the polymer described in Example 1, 0.2 pbw. 4'-tert-butyl-9-phenyl-acridine,

0.02Gt. of the dye used in Example 12

and
20.0 Gt. Ethylene glycol monoethyl ether

prepared and applied to a mechanically roughened, 0.3 mm thick aluminum foil by spin coating and dried.

Exposure and development are carried out as in Example 1. The quality of the printing form obtained corresponds to that described under Example 2.

Example 15
A coating solution is made

2.5 Gt. the in example! 1 described polymer, 0.2 Gt. 6-chloro-4 ', 4 "-dimethoxy-2,3-diphenylquin-

oxaline,

0.25 Gt. of the wetting agent used in Example 8,
0.02 G t. Ethyl violet (Cl. Basic Violet 4) and
15.0 Gt. Ethylene glycol monoethyl ether

produced and applied to a monofilament polyamide fabric, which has 120 threads per cm, and dried.

It is exposed for 5 minutes under a negative original using a tube exposure device according to the example 1 and then 2 minutes with the developer specified in Example 1.

The stencil obtained in this way can be used for screen printing.

Example 16

A coating solution according to Example 15 is applied to the cleaned copper surface of a carrier consisting of a plastic plate with a laminated copper skin and dried. Dry layer weight: 10 g / m ² .

Then a tube exposure device according to Example 1 is used for 10 minutes under a positive original exposed, developed for 30 seconds with the developer specified in Example 1 and then with a ferric chloride solution of 42 ° Be for 20 minutes etched.

The copying layer used is characterized by an excellent etch resistance and a good one Resolving power off.

Example 17
A coating solution is made

2.5 Gt. of a methyl methacrylate / methacrylic acid copolymer with an average molecular weight of about 20,000 and an acid number of 95,

0.01 Gt. Rhodamine B,

0.2 Gt. 2,3-bis (4'-methoxyphenyl) -

5,6-dihydropyrazine,
20.0 Gt. Ethylene glycol monoethyl ether

prepared, applied to electrochemically pretreated 0.1 mm thick aluminum by spin-coating at 100 revolutions per minute and ^{dried at 100 °} C. for 2 minutes.

The plate is then placed under a positive template at a distance of 72 cm with an 8000 W xenon lamp Exposed for 2 minutes. Development is carried out by wiping over with that given in Example 1 Developer within 35 seconds.

After fixing with 1% phosphoric acid, it is colored with bold paint.

The quality of the printing form obtained is similar to that described under Example 3.

Example 18
A coating solution is made

2.5Gt. the in example! 17 described polymer.

0.15 Gt. 2,5-bis (2 ', 4'-dimethoxyphenyl) pyrazine.

0.01 Gt. Rhodamine B,

0.2Gt. of the wetting agent used in Example 8

and
20.0Gt. Cyclohexanone

prepared and on 0.1 mm thick, electrochemically pretreated aluminum by spinning at 100 Revolutions per minute applied. After drying, the plate is placed under a positive template 2 Minutes exposed from a distance of 72 cm by an 8000 W xenon lamp.

This exposed plate is made in 45 by wiping over with the developer given in Example 1 Developed in seconds and colored with protective paint after treatment with 1% phosphoric acid

The quality of the printing form obtained corresponds to that of that described under Example 17.

Claims (5)

Patent claims: 1. Photosensitive mixture, the solubility of which is increased by exposure to light, and which is a polymer with acidic substituents and contains an initiator, characterized in that the Initiator is an N-heterocyclic compound, the at least one pyridine, pyrazine or dihydropyrazine ring and at least one benzene ring as Contains substituents or in fused form and optionally not others on these rings carries photosensitive substituents 2. Photosensitive mixture according to claim 1, characterized in that the N-heterocyclic Compound is of high molecular weight and contains a large number of N-heterocyclic radicals. 3. Photosensitive mixture according to claim 1, characterized in that the N-heterocyclic Compound an acridine, a 2,3-diphenylquinoxaline substituted by methoxy groups or a phenazine is. 4. Photosensitive mixture according to claim 1, characterized in that it is a polymer with Contains carboxylic acid, phosphonic acid, sulfonic acid or N-arylsulfonyl urethane groups. 5. Photosensitive mixture according to claim 1, characterized in that it contains 0.5 to 30 parts by weight of N-heierocyclic compound per 100 parts by weight Contains polymer.