FR2609187A1 - PHOTOPOLYMERIZABLE MATERIAL, WHICH MAY SUPPORT MODERATE HEAT - Google Patents

Abstract

THE INVENTION CONCERNS A PHOTOPOLYMERISABLE MATERIAL, INTENDED IN PARTICULAR FOR THE RECORDING OF INFORMATION. THIS MATERIAL INCLUDES A PHOTOSENSITIVE LAYER CONTAINING A MODIFIED MALEIC ANHYDRIDE COPOLYMER, GENERATOR OF POLYELECTROLYTE COMPLEXES COAGULATING DURING DEVELOPMENT AND INCLUDING SEVERAL SALT-FORMING GROUPS AND PRESENTING AN AVERAGE MOLAR MASS OF 20,000 TO 50000 EPAIS. IS LESS THAN 30 MM. APPLICATION: OBTAINING A MATERIAL WITH A GOOD CONTRAST BETWEEN LIT AND UNLIT ZONES DURING EXPOSURE, FOR PHOTOGRAPHIC REPRODUCTION AND OR REPROGRAPHY.

Description

The invention relates to a photopolymerizable material which is suitable for

  the recording of information, in particular as a reproduction material, for the manufacture of printed circuits

  and printing plates for printing or

  hardened image forming clothes. It is known that the polymerization of a large number of ethylenically unsaturated compounds can be caused by the fact that a photoinitiator forms, under the influence of light, radicals which initiate a polymerization. A series of compounds is known which, under the influence of light and according to mechanisms of

  more diverse, form radicals that can trigger the photo-

  polymerization (see H. Baumann, H. Timpe, H. Bbttcher, Z. Chem.

23 (1983) 197).

  With the aid of these photoinitiators, photopolymerizable layers can be formed which, in addition to the photoinitiator, contain

  polymerizable or crosslinkable compounds and a binder.

  As during storage, polymeric binders, as well as other hydrocarbons, are oxidatively degraded

  due to oxygen in the air and that for many vinyl monomers

  The total activation energy of the crude polymerization rate without a priming step is only 20 kJ mol-1 (J. Ulbricht, Grundlage der Synthese von Polymeren / Fundamentals of Polymer Synthesis / Akademie-Verlag Berlin, 1978), inhibitors are judiciously added to the photopolymerizable layers. These

  inhibitors increase the storage stability of

  polymerizable and thus prevent thermal fogging.

  The patent literature describes, as inhibitors, the following classes of substances: phenols, for example, pmethoxyphenol, t-butylcatechol, bt-naphthol, hydroquinone, quinones, for example p-benzoquinone 2,5-diphenyl-p-benzoquinone, organic nitrogen compounds, for example amines (US-A-4,167,415 and US-A-4,057,431, GB-A-1,553,823; DE-A-2,517,034, US-A-4,053,317), N-nitroso compounds (DE-B-1,291,620, US-A-4,055,317, US-A-3 615,629), thiourea, thiosemicarbazides, thiosemicarbazones (patent application DE-A-3,013,170), organic phosphorus compounds, for example phosphines (US-A-3,932,188, US-A-4 Phosphites (DE-A-1,934,637, DE-A-2,104,958, DE-B-1,098,712, US-A-4,116,788), epoxides, for example , 2-epoxydecane, glycidyl acrylate, styrene oxide (US-A-4,146,453 and organic sulfur compounds (US-A-4,168,981, DE-A-1,282,447). Inhibitors are generally used in a concentration of 0.001 to 10%,

  relative to the compound to be polymerized.

  In addition to initiators, inhibitors, monomers and binders, the photopolymerizable layers may optionally contain one or more additives such as plasticizers, pigments or dyes. In addition, "extinguishers" are also added

  or oxygen inhibitors, for example bis-tetrahydrofuran

  carboxamide (patent application DE-B-2 245 549) to the photopolymer layers

  merishable to decrease the inhibitory influence of oxygen.

  The photopolymerizable layer is then applied to the

  support by spreading a solution or dispersion of all

  individual posers. Suitable materials are natural materials

  various types of synthetic or synthetic materials that can be manufactured

  in the form of flexible or rigid sheets or plates.

  For the production of the images, the photopolymerizable layers are cured during exposure to form an image. Hardening of image formation usually leads to

  not to obtain immediately visible images but to modify

  cation, as a result of polymerization or crosslinking, of the properties

  of illuminated regions, to form images. These changes

  Property properties can then be used in a subsequent developmental step to obtain image visualization (see H. Bâttcher, J. Signal AM, 8 (1980) 405). After the development, it is possible to obtain embossed plates on the support material which can be used as a printing block or matrix or which can give, after coloration, a transparent image or

opaque.

  The object of the invention is the development of photopolymerizable materials giving a better rendering of details

  and having a better thermal stability during storage.

  The problem of finding organic compounds for photopolymerizable materials capable of reducing the halo effects of reflected light and diffuse light and of preventing thermal formation of the invention is at the core of the invention. a veil without harming the sensitivity (reactivity)

of the material.

  According to the invention, this problem is solved by the fact that a photopolymerizable material, constituted by a support, at least one photosensitive layer which consists of a monomer, an initiator,

  binder, inhibitor and other additives, as well as

  other auxiliary layers, contains compounds having N-oryl structural units corresponding to formula I:

R RI

27 N 4

R R

  in which the symbols R to R, which are identical or different, each represent a hydrogen atom or an alkyl group which are present in the free state and / or fixed by coulombic and / or covalently bonded interactions, in the form of of segments

  of polymer chain or substituents of a polymer.

  Preferably, sterically hindered cyclic N-oxyl compounds of the formula II having 5- or 6-membered rings are added to the photopolymerizable layers, and wherein the R-R symbols each represent an alkyl group having

1 to 4 carbon atoms.

  Advantageously, hexagonal cyclic N-oxyls, which correspond to formula III, are used in the layer in the free state and / or in the fixed state by coulombic interactions and / or according to formula IV. are present to reason

  from 1 to 50 mol% in a copolymer, a terpolymer or a

  polymer, which itself is the binder of the layer or that

add to this binder.

  As substituents, R 3 is advantageously used for a methyl group CH 3; for X a NR group, -O-; for R a C 1 -C 18 acid residue, for example an acetyl, benzoyl, salicyl or 2-ethylhexanoyl residue; R can be H or CH3; Y may be a carboxy group of a modified maleic acid unit that forms with maleic acid units modified with styrene and / or methyl methacrylate, with vinyl acetate, with vinyl ether, with alpha methylstyrene, propylene and

  other alpha-olefins a copolymer, a terpolymer or a

polymer.

R5

X

-I -

3 Y_ / n

R 'R R R RR

R2 N R4

IV

  formulas in which R to R, identical or different, represent

  each feel a hydrogen atom, or an alkyl group; R5 represents a hydrogen atom or an alkyl or aryl group or a C18 C18 acidic residue; R represents a hydrogen atom or a CH3 group; Y represents a group.C.0, or an alkylene group

or -NR6; and n is 0 or 1.

  However, it is also possible to use polymeric N-oxyls which contain, in addition to N-oxyl substituents attached to the

  polymer, piperidine residues attached to the polymer.

  The concentration of the N-oxyl groups is in the layer according to the monomer used, between 10 and 104 parts per million (pr), relative to the monomer. The photopolymerizable layers also contain organic compounds,

  which have one or more polymer groups (monomers)

  sands by radical way. In addition, the photopolymeric layers

  sand contains a natural or synthetic binder. The addition of a binder is especially advantageous when the compounds used,

  intended to be polymerized, constitute liquid substances.

  Suitable binders are polymers or polymer blends which after exposure have sufficiently high solubility in the developing agent. As polymers, are suitable

  such as gelatin, polyvinyl alcohol, polyvinyl

  pyrrolidone, copolymers of maleic anhydride with styrene, alpha-methylstyrene, propylene, methyl methacrylate. Thanks to the use of binders comprising carboxyl groups, the diffusion resistance of the N-oxyls used is increased.

  To initiate photopolymerization, one adds to the

  photopolymerizable initiators which form, under the

  fluence of light and from the most diverse mechanisms, radicals that then trigger a polymerization or

  crosslinking. The photopolymerizable layers are furthermore

  in that, depending on the purpose for which the application is

  add plasticizers, pigments or dyes.

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  The best way to apply photopolymers

  meritorious on the support is to apply a solution or dispersion of all the individual components. Suitable supports are the various natural or synthetic materials that can be produced in the form of sheets or

  flexible or rigid plates, such as

  copper, oriented polyester film, coated papers, glass, aluminum

  treated with alumina powder, silicon and wood.

  In order to form images, the photopolymerizable materials are caused to cross-link, that is to say, to cure their irregation. The exposure of the layers produced according to the invention is carried out by means of the lamps, which are customary in the technique of reproduction or reprography, with high-pressure mercury vapor, with Xenon lamps under very high pressure, or with lamps halogen. But sunlight is also suitable for eypositioning. near the imaging exposure, development takes place using a solvent or solvent mixture corresponding to the total system. The necessary development time is judged on the layer thickness, the binder used and the temperature. But, in general, the time of

  development is less than 10 minutes.

Example 1

  With the aid of a squeegee corresponding to 0.25 micron, a mixture consisting of 60 parts of a styrene copolymer and a polyethylene terephthalate film is cast on a PETP (polyethylene terephthalate) sheet.

  butyl half ester of maleic acid, 50 parts of tetra-

  pentaerythritol acrylate, 2 parts of Michler's ketone,

  parts of benzophenone, 10 parts of diphenyl

  iodonium, 0.02 part of N-oxyl of formula III, in which

  the symbols R to R4 each represent a CH3 group; R5 represents

  CH 3 CO- and X is -NH-, 200 parts butanol and 620 parts methanol, and is dried at room temperature. Exposure with a mask takes place for seconds using a mercury vapor lamp, "HBO 500", placed at a distance of 80 cm. After the development using a 2% aqueous solution of Na2CO3, a cliché is obtained, which can be colored, for example

  using turquoise blue "Solamine".

Example 2

  Using a doctor blade corresponding to 0.1 nm, it is applied to an aluminum plate treated with alumina

  a mixture consisting of 77 parts of a copo-

  maleic acid styrene and half-butyl ester, 43 parts of N, N-dimethylaminopropylacrylamide, 2 parts of Michler's ketone, 10 parts of benzophenone, 10 parts of diphenyliodonium chloride, 0.015 part of N-oxyl of formula II, in which the symbols R to R4 each represent a group CH3, R5 represents a group CH3CO- and X represents a group -NH-,

  600 parts of methanol and 250 parts of butanol.

  The thickness of the dry layer is, after drying at

  room temperature, 8 m (micrometers).

  The imaae training exhibition of the ma-

  This is done for 15 seconds using an HBO 500 lamp placed at a distance of 80 cm. After the development with water, we obtain a cliché that we can color by

  example using bright red "Walk".

Example 3

  A mixture consisting of 60 parts of a styrene copolymer and the propyl half-ester of maleic acid, 40 parts, is applied to a "Cellite" sheet with a doctor blade corresponding to 0.25 mm. pentaerythritol tetraacrylate, 10 parts methylenebisacrylamide, 2 parts Michler's ketone,

  parts of benzophenone, 10 parts of diphenyl

  iodonium, 0.02 part of N-oxyl of formula III, in which

  the symbols R to R each represent a group CH3, R5 represents

  PhCO and X is -O-, 600 parts of methanol and 250 parts of propanol, and is dried at room temperature. The imaging exposure occurs for 10 seconds using an HBO 500 lamp

placed at a distance of 80 cm.

  After development using a 1% KOH solution, a cliché, which can be stained, is obtained.

example with black "Wofalan".

Example 4

  With the aid of a doctor blade of 0.25 mm, a mixture of PETP (polyethylene terephthalate) and a non-stretched

  consisting of 76 parts of a styrene copolymer and hemi

  butyl ester of maleic acid, 40 parts of N, N-dimethyl-

  aminopropylacrylamide, 10 parts of triethanolamine trisacrylate, 2 parts of Michler's ketone, 10 parts of benzophenone, 10 parts of diphenyliodonium chloride, 1 part of a polymeric N-oxyl of formula IV, which consists of 50 mole% styrene , 48 mol% maleic acid half-ester and 2 mol% maleic acid 4- (2,2,6,6-tetramethylpiperidino-N-oxide) hemiamide, 250 parts butanol and 600 parts methanol , and one

  then dry at room temperature.

  The imaging exposure takes place for 10 seconds using an HBO 500 lamp placed at a distance of 80 cm. After the development with water, we get a picture that can be colored for example using turquoise "Solamine".

Example 5

  A mixture consisting of 50 parts of gelatin, 25 parts of polyvinyl alcohol), 2 parts of ketone, is applied by means of a 0.1 mm squeegee to an aluminum-aluminum plate. Nit-disulfonated in m, m ', 10 parts of the sodium salt of p, benzophenone disulfonic acid, 10 parts of diphenyliodonium acid sulfate,

  parts of acrylamide, 40 parts of N, N-dimethylaminopropyl

  acrylamide, 20 parts of methylene bisacrylamide, 0.04 part of N-oxyl of formula III, in which the symbols R1 to

4 5

  R4 are each CH3, R5 is CH3CO and X is -NH-, 1200 parts water and 300 parts methanol;

  and is dried at room temperature.

  The imace formation exposure takes place for 15 seconds using an HBO 500 lamp placed at a distance of 80 cm. After the development with water, it is possible to arrange a snapshot that can be colored for example with the aid of

methylene blue.

Example 6

  A mixture consisting of 50 parts of polyvinylpyrrolidone, 10 parts of a copolymer of 2-methylstyrene and half-butyl maleic acid, 30 parts of tetraacrylate is cast with the aid of a scraper of 0.25 mm. of pentaerythritol, 10 parts

  of trisacrylformal, 10 parts of glycerol trisacrylate, 2 parts of

  Michler ketone, 10 parts benzophenone, 10 parts diphenyliodonium chloride, 0.01 part N-oxyl of formula III, wherein R 4 to R 4 are each CH 3, R 5 is CH 3 CO- and X is -0-,

3 -1 3

  250 parts of ethanol and 600 parts of methanol, and

  then dry at room temperature.

  The imaging exhibition takes place

  for 10 seconds using an HBO 500 lamp placed at a dis-

  80 cm. The development takes place with methanol and gives a cliché, which can be colored for example with

methylene blue.

  Examples 7 to 12 The material samples, unexposed of Examples 1 to 6, are kept at room temperature for 2 hours and a half at 50 ° C. The samples thus treated are then exposed in a similar manner to Examples 1 to 6. and colors them. We obtain shots completely devoid of veil, whose rendering of details corresponds to that of the materials

examples 1 to 6.

  Examples 13 to 18 To further verify the thermal stability during storage, 100 μl (microniters) of each of the mixtures of the examples are applied! to 6 on 1 cm nickel plates and then dried. The reactivity of the corresponding material is determined by means of these samples, by photocalorimetry, and is considered to be equal to 1. After drying for 2.5 hours at 50 ° C., other sample plates containing mixtures are preserved. Examples 1 to 6 and then subjected to photocalorimetry tests. Table 1 again shows the very good thermal storage stability of the materials examined. EXAMPLES 19 TO 24 (comparative examples without N-oxyl) Examples 1 to 6 are applied, on the corresponding supports, to mixtures of Examples 1 to 6, but without the addition of the corresponding Noxyls, they are dried and dried. It is then stored for 2.5 hours at 50 ° C. The materials thus treated are treated according to Examples 1 to 6 and developed. We get clichés totally veiled

  without rendering details, which are not suitable for recording

very much information.

  Examples 25 to 30 (comparative examples without N-Oxyl) One microliters of each of the mixtures of Examples 19 to 24 were applied to 1 cm nickel platelets, dried, stored for 2 hours and

  half to 50OC then they are subjected to photocalorimetry examinations.

  After the heat treatment, the reactivity of the samples

decreases by 90% (see Table 1).

  Table 1: Relative Reactivity of Light-Cured Blends

  before and after a storage of 2 hours and a half at 50C.

  Example Reactivity layer composition according to the relative example

13 1 0.98

1 (without N-oxyl) 0.12

14 2 1

26 2 (without N-oxyl) 0.10

3 0.98

27 3 (without N-oxyl) 0.12

16 4 1

28 4 (without N-oxyl) 0.13

17 5 0.94

29 (without N-oxyl) 0.06

18 6 0.99

  6 (without N-oxyl) 0.11 Example 31 (Prior Art) Using a 0.25 mm squeegee, a mixture consisting of 60 parts of polyethylene terephthalate (PETP) was cast on a PETP (polyethylene terephthalate) sheet. styrene copolymer and maleic acid half-ester, 50 parts of pentaerythritol tetraacrylate, 2 parts of Michler's ketone, 10 parts of benzophenone, parts of diphenyliodonium chloride, 0.2 part of ether

  monomethyl hydroquinone, 200 parts of butanol, 620 parts of

  of methanol and dried at room temperature.

  The exposure of the material is then carried out for 30 seconds using an HBO 500 lamp placed at a distance of 80 cm. After the development with water, we obtain a cliché that we can color for example with

turquoise blue "Solamine".

  If the unexposed material is stored for 2.5 hours at C and then exposed under the above conditions, after

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  with water, a strongly veiled image which, after coloring, shows only insufficient differences in color density between the exposed and non-

insolated of the imaae.

R EV E N D I C A T I 0 N S

  1. A photopolymerizable material comprising at least one photosensitive layer consisting of a monomer, an initiator, a binder, an inhibitor and other additives, as well as possibly other auxiliary additives, characterized in that it contains compounds comprising the N-oxyl structural units corresponding to the formula:

R12 'R3

2> N '4I

R 1 R

  o0 / in which the symbols R to R, identical or different, each represent a hydrogen atom or an alkyl group7, which are present in the layer in the free state and optionally or alternatively are fixed by coulombic interactions and / or are covalently attached in the form

  of polymer chain segments or substituents of a polymer.

  2. photopolymerizable material according to claim 1, characterized in that it contains cyclic N-oxyls, exhibiting steric hindrance, with pentagonal or hexagonal rings, of formula II: Ri R3 I

R2 N R4

  wherein the symbols R to R are the same or different and each represents an alkyl group having 1 to 4 carbon atoms.

  3. Photopolymerizable material according to one of the claims

  1 and 2, characterized in that it contains N-oxyl

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  of hexagonal compounds, which have the formula III, are present in the free state and / or are fixed by coulombic interactions in the layer and / or respond to the

  formula IV and represent 1 to 50 mole% of a copolymer

  mother, a terpolymer or a multipolymer:

R5 71_ _

tii / _ L / n

X X

R1 R3 R 'R3

R2 N R R2 R4

o III 0 IV

1 4

  formulas in which the symbols R to R, which are identical or different,

  each, represent an alkyl group having 1 to 4 carbon atoms; R5 represents a hydrogen atom, an alkyl, aryl, acyl group, a C1-C18 acid residue; R6 represents a hydrogen atom or a CH3 group; X is NR, -, -S- or -C-; Y represents a group C, an alkylene group or -NR; and

n is 0 or 1.

  4. Polymerizable material according to any one of

  claims 1 to 3, characterized in that it contains the

  N-oxyl structural units present in a concentration

  between 10 and 104 ppm (parts per million)

relative to the monomer.