DE2135691C3 - Recording method for the vesicular method - Google Patents

Description

where η is greater than 4, preferably 7 to 50 and X represents a nonionic hydrophilic group

2. Recording material according to claim!, Characterized in that the surfactant is fluorocarbon is present in an amount of about 0.01 to 5.0 weight ° / o of the polymeric binder

3. Recording material according to claim 1 or 2, characterized in that the surface-active Fluorocarbon is present in an amount from about 0.05 to 2.0 percent by weight of the polymeric binder is

4. Recording material according to claim 1, characterized in that the compound which decomposes on exposure to elimination of nitrogen, represents a diazo compound

5. Recording material according to claim 4, characterized in that the diazo compound in an amount of from about 1 to 10 weight percent, preferably from 4 to 6 weight percent, of the polymer Binder is present.

6. Recording material according to claim 1 to 5, characterized in that the polymeric binder a linear polyhydroxy ether νο.τ 2,2'-bis (p-hydroxyphenyl) propane and is epichlorohydrin

The invention relates to recording material for the vesicular process with a polymeric binder, which is a compound that decomposes upon exposure to the elimination of nitrogen, as well as a surface-active one Substance contains The polymeric binder can be applied to a suitable film base. If the material is exposed imagewise, the photosensitive compound decomposes with elimination of nitrogen. Then the material is heated up to its softening point, whereby the gaseous Molecules collect and expand to form bubbles in the film. The bubbles thus formed reflect the light and reproduce the picture.

Usually used as compounds, which on exposure to elimination of nitrogen decompose, diazonium compounds. The conventional polymeric binders show very little Permeability to nitrogen. Examples of suitable polymers are vinylidene chloride homopolymers and copolymers with acrylonitrile, methacrylonitrile homopolymers, poly (vinyl formaldehyde) and poly (hydroxy ether) derivatives of dihydroxyphenols and epichlorohydrin.

Since the nitrogen bubbles are the actual light-scattering particles, it is necessary to regulate the size and size distribution of these bubbles in order to avoid the 691

to be able to vary the optical properties of the finished vesicular film as desired. The bubbles should be large be enough to reflect light but small enough to obtain a high definition film.

The bubble size can be controlled to some extent by adjusting the developing temperature will. So at lower temperatures the polymeric binder is more viscous and prevents the formation of bubbles required deformation; consequently, it inhibits the growth of the bubbles. Conversely, if that Polymers soften at higher temperatures », larger deformations possible, leading to larger bubbles to lead.

Although smaller at relatively lower temperatures for a given polymeric binder Bubble sizes and consequently higher resolving power can be educated, it has been found that Vesicular films developed at temperatures at the lower end of their development temperature range, exhibit poor image stability at elevated temperatures and high humidity. Low development temperatures also lead to poor utilization of the available nitrogen - the gas forms small bubbles, but in the same number as larger bubbles at a higher development temperature, see above that a significant reduction in the total gas volume is the result. It is therefore desirable bubble size and distribution by means other than by resorting to smaller ones To regulate development temperatures. One possibility is to use a controlled number of nucleation sites to create where the formation of nitrogen bubbles takes place The more nucleation sites are present for a given amount of nitrogen released during the exposure time, the smaller the size of the bubbles formed and consequently the greater the resolution.

From US Patent 32 60 599 is the use of saponin as a surfactant wetting agent to improve exposure properties of the solutions used to produce vesicular films are known. Most of the time, however, they were surface-active Means only to improve the even distribution and the outflow of the Coating mixture used.

However, if saponin is used, it will not be sufficient in developing the exposed material small bubbles formed. Accordingly, the invention has set itself the task of surface-active To make substances available that are used in the development of the recording material for the vesicular process of the type described above result in small gas bubbles, so that a higher photosensitivity and a better resolving power of the vesicular recording material is achieved.

The recording material according to the invention is characterized in that the surface-active Substance a fluorocarbon of the general formula

where η is greater than 4, preferably 7 to 50 and> represents a nonionic hydrophilic group.

The fluorocarbon surfactant has a hydrophobic non-polar portion; H. a long fluor carbon chain 'and the hydrophilic nonionic group X, which is an organic group such as - CH2OH

- COOH etc. can represent. Group X can either directly or through an intermediate group such as an ester, ether, amide, etc. to the hydrophobic part of the molecule be bound.

N-polyoxyethylene-substituted perfluorosulfonamides are preferably used as surface-active substances the formula

C ₈ F ₁₇ SO ₂ N (C ₂ H ₅ ) (C ₂ H ₄ O) ₁₇₁ H

used, where m is an integer from 2 to 30. These substances have the property that they reduce the surface tension of water for a 0.001 percent by weight solution to 25 dynes / cm at 25 ° Cherabsetzea

The effective concentration of fluorocarbon surfactant depends on the solvent system, the type of diazo compound and the concentration and type of polymeric binder used away. Usually the fluorocarbon surfactant is in an amount of about 0.01 to 5, preferably from about 0.05 to 2 percent by weight of the polymeric binder.

The compound which decomposes with elimination of nitrogen on exposure to light is preferably one Diazo compound. It is preferably in an amount of about 1 to 10% by weight, particularly preferred used in amounts of about 4 to 6% by weight, based on the polymeric binder. Big amount of do not lead to any further improvement in film speed or resolution, and at Concentrations of 20% by weight and above tend to cause the compound to precipitate out of solution.

Some suitable compounds are given below as examples:

p-diazo-diphenylamine sulfate,

p-diazo-dimethylaniline zinc chloride,

p-diazo-diethylaniline zinc chloride,

p-diazo-ethyl-hydroxyethylaniline-

72 zinc chloride,

p-Diazo-methyl-hydroxyethylaniline-

U 2 zinc chloride,

p-Diazo-2 ^ -diethoxy-benzoylaniline-

1/2 zinc chloride,

p-diazo-ethyl-benzylaniline - '/ 2 zinc chloride,

p-diazo-dimethylaniline-boron fluoride,

p-Diazo-1-morpholino-benzene - '/ 2 zinc chloride,

p- Diazo-23 -dimethoxy-1 -p-toluyl-

mercaptobenzene - '/ 2 zinc chloride,

p-Diazo-3-ethoxy-diethylaniline-

< Ii zinc chloride,

2,5,4'-triethoxy-diphenyl-4-diazonium oxalate,

p-Diazo-2 ^ -dibutoxy-benzoylaniline-

1/2 zinc chloride,

p-diazo-diethylaniun-i / 2 zinc chloride,

p-diazo - ^ - dibutoxy-l-morpholino-

benzene chloride-zinc chloride,

p-Diazo-2 ^ -dimethoxy-l-morpholino-

benzene chloride-zinc chloride,

p-Diazo-2,5-diethoxy-l-morpholino-

benzene chloride- ^ zinc chloride,

2-diazo-1-naphthol-5-sulfonic acid,

p-diazo-diethylaniline-boron fluoride,

p-Diazo-2-chloro-diethylaniline-

'/ 2 zinc chloride.

Decompose exposure with elimination of nitrogen, include the quinonediazides

SO ₃ Na
and azide compounds of the type

N ₃

SO ₃ H

SO ₃ H

Also the carbazido compounds (carboxylic acid azides), which have a hydroxyl or amino group in the ortho position to the carbazido group (cf. USA patent 31 43 418) are suitable

Of the polymers mentioned at the outset, linear polyhydroxy ethers in particular are used as polymeric binders of epihalohydrins and dihydric phenols, preferably the linear polyhydroxy ether of 2,2'bis (p-hydroxyphenyl) propane (bisphenol A) and epichlorohydrin. Other suitable Polyhydroxy ethers are given in the German patent application P 20 50 641.6.

As with the known processes, it is most beneficial to use the polymeric binders and additives bring together in suitable solvents. The polymeric binders can be used in large numbers be dissolved by solvents, e.g. B. in methyl ethyl ketone, tetrahydrofuran, dioxane, 2-ethoxyethyl acetate, chlorinated solvents such as ethylene dichloride, toluene and solvent mixtures such as methyl ethyl ketone / Butanol / Toluene A diazo compound is preferably used in a small amount of a polar solvent, such as methanol, aqueous methanol, acetonitrile or nitromethane dissolved and the stirred polymer Binder added dropwise. Preferably, but not necessarily, the solvent in which the Diazo compound is dissolved, compatible with the solvent for the polymeric binder. Are the two solvents compatible with one another, so is the possibility that the diazo compound or the Polymer precipitates when the two solvents are mixed, practically excluded.

The fluorocarbon surfactants can be dissolved in a wide variety of solvents. In general, the preferred solvents are polar and / or have good hydrogen bonding properties. It is desirable that these solvents have a boiling point in the range of about 50 ° to 160 ⁰ C. Particularly preferred systems consist mainly of one or more of the following solvents: alcohols with one or more carbon atoms, preferably not more than 5, such as methanol, ethanol, propanol, etc; Alcohol ethers, e.g. B. those of the formula

C _n H _{2n + 1} OCH ₂ CH ₂ OH
where η = 1 - 5; Ester, ζ. Β. those of the formula

Other suitable compounds found at CH ₃ COOC _n H _{2n + 1}

2! 35

where π = 1; Ether esters, ζ. Β. those of the formula C _n H _{2n + 1} OCH ₂ CH ₂ CH ₂ OCOCH ₃

where η = 1 - 5; cyclic ethers, ζ. B. 1,4-dioxane and tetrahydrofuran; Ketones, ζ. Β. those of the formula

where χ and y each represent 1-5; Nitroalkanes of the general formula

C _n H _{2n + 1} NO ₂

where η = 1 - 4, and chlorinated hydrocarbons, such as ethylene dichloride, and chlorinated hydrocarbons in which the molar ratio of ChHr to carbon is greater than 1, e.g. chloroform, methylene chloride, trichlorethylene, trichloroethane, tetrachloroethane, and the like, including 2 ^ -Dichlot diethyl ether and chlorobenzene; and various solvents such as dimethylformamide, acetonitrile and tetramethylurea.

The following examples serve only to illustrate the invention.

Comparison game

Various known surface-active and dispersing substances, which are used in vesicular films to improve the flow behavior of the coating, a polymeric binder made from the polyhydroxy ether of bisphenol A and epichlorohydrin, were mixed in to have their effect on the sensitivity of the film and the bubble size, i.e. the resolving power, to determine.

To 18.75 g of a 20 <ybigen solution, which can be obtained by diluting a polyhydroxyether from bisphenol A.

Table I.

35

and epichlorohydrin (40% solids m methyl ethyl ketone) obtained with tetrahydrofuran (ratio of methyl ethyl ketone to tetrahydrofuran = 75:25) dropwise a solution of 0.15 g of p-diazo-N, N'-diethvlaniline zinc chloride in 1.80 g of methanol added 0.75 g of a 5% solution which contains the surfactant.

The diazo compound is dissolved in methanol or Dissolved dimethylformamide, the choice of solvent on the compatibility of this solution with the Surfactant solution is dependent. The solvent mixture becomes the polymer added dropwise and stirred steadily for 10 minutes. The film is then cut to a 0.07 mm thick using a coating knife at a distance of 0.15 mm biaxially oriented polyethylene terephthalate film applied and in an oven with air circulation 10 Dried for minutes at 90 ° C. The dried films are immersed in distilled water for 30 seconds immersed at 70 ° C and then wiped dry. The films obtained are then passed through a step wedge 30 Illuminated for seconds through two parallel fluorescent tubes (80 watts each), which are at a distance about 5 cm from the surface of the step wedge.

The exposed films are developed immediately by passing it through one brought to 90 ⁰ C developers. The developed samples are then examined under a high-magnification microscope (900 times) for the size and distribution of the bubbles. In addition, the optical density of each stage is determined using a transmission densitometer with an aperture of 4.5

Table 1 shows the optical density measurements of some vesicular films obtained as described above under Use of the various dispersants were made.

Dispersants

Level no. 2 3 4th 5 1 0.10 0.06 - 0.28 0.55 0.25 0.10 0.05 0.90 0.40 0.24 0.14 0.05 0.90 0.25 0.10 0.06 - 0.50 OJO 0.07 - - 0.30 0.72 0.40 0.26 0.18 1.08 0.20 0.10 0.06 0.05 0.40 1.00 0.40 0.10 - 1.44

Without

Sodium lauryl sulfate

Sodium dioctyl sulfosuccinate

Stearyl-dimethylbenzyl-ammonium chloride

Polyethers based on alkoxylated triols

Saponin (reagent grade)

N atrium alkyl naphthalene sulfonate

Soy lecithin (purified)

Since the step wedge is transparent at level 1, the impermeability is increased at every further level (higher number) is enlarged, the measurement of the optical density at level 1 gives the maximum image density of the relevant film at a given exposure. It can be seen that surfactants are the optical Increase density to varying degrees.

Film speed is a relative measure of the amount of light that is necessary to get a film up to develop a certain density. The higher the film speed, the lower it is for development amount of light required for the film. In other words, the more sensitive the film, the denser the film image at a given exposure. Table I shows that the surfactants increase sensitivity.

0.10

0.10

because at a certain exposure the film frames have a greater density.

Microscopic examination of the bubbles in all of these samples shows a very wide spread of the Bubble sizes from less than 0.5μ to greater than 5.0μ within each sample. The result is unsatisfactory,

since the larger bubbles correspond to a lower final resolution of the vesicurlar image. In addition, the evolved nitrogen not used as well when larger bubbles are present.

In contrast, it was found that surface

6 <i active fluorocarbons not just a significant one Increase in sensitivity is achieved, but also very small bubbles (0.5 μ or smaller) in the developed image can be obtained which has an enhanced

Condition dissolution. The following example shows the differences to the known surface-active ones Means.

example

The effect on film resolving power and optical density by adding the nonionic fluorocarbon surfactant

C ₈ F ₁₇ SO ₂ N (C ₂ H ₅ ) (C ₂ H ₄ O) ₂ -J ₀ H

was used for three different vesicle containing films, i. H. different binders, determined.

(1) A polyhydroxy ether made from bisphenol A and epichlorohydrin; (2) a polyvinyl formaldehyde; and (3) a Vinylidene chloride-acrylonitrile copolymer solutions of the polymer, the solvent and the nitrogen-evolving Substances were prepared as in the comparative example

The binder (2) starting solution was prepared as follows:

3.75 g of the binder (2) were dissolved in 27.50 g of ethylene dichloride and a solution of 0.15 g of the

Table II

Diazo compound in 1.80 g of methanol was added dropwise. The surfactant (0.75 g) was found to be 5% Solution in methyl ethyl ketone added.

The starting binder (3) solution was prepared by dissolving 3.75 g of Binder (3) in 21.25 g Methyl ethyl ketone and adding 0.15 g of the diazo compound in 1.80 g of methanol prepared Surfactants (0.75 g) were supplied as 5% solutions, the above-mentioned fluorocarbon in

ίο methyl ethyl ketone and saponin in water, added. the

Binder ^ i) starting solution was based on the same Manufactured in a manner that only the fluorocarbon was added as a 5% solution in methyl ethyl ketone.

The films once produced were coated,

• 5 dried, treated with water, then exposed and, as described in the comparative example, developed. To determine the resolving power, the film was exposed for 20 seconds through a dissolution test object (USAF target No. 8007 P) with parallel bundled UV light from a microscope lamp, which was arranged at a distance of about 30 cm from the sample. The films were prepared with the binders (1) and (2) were carried out at 7O ⁰ C, those that were prepared with the binder (3) developed at 120 ° C.

Polymer
binder

Surfactant dissolution
Lines / mm

without 64 1.10 0.76 0.40 0.14 0.06 - modified with ethylene oxide 51 1.25 0.85 0.45 0.16 0.10 0.06 Castor oil Fluorocarbon 90 1.54 1.30 0.62 0.18 0.08 0.06 without 81 1.48 1.02 0.45 0.14 0.06 Saponin (reagent grade) 81 1.48 1.12 0.54 0.18 0.06 Fluorocarbon 144 1.56 1.40 0.70 0.23 0.10 0.06 without 28 1.20 1.10 0.63 0.06 Disodium ethoxylated nonyl 32 1.22 0.82 0.50 0.30 0.16 0.07 phenol half-esters of sulfobernic stinic acid Fluorocarbon 90 1.58 1.32 0.80 0.62 031 0.16

The resolution test object used here is placed over the films to be examined and pictorially exposed The dissolution test object is opaque and contains a number of lines of varying thickness, through which the light can pass through kana After exposure, the vesicular films are developed and the image becomes viewed under a microscope The resolving power is measured with reference to the finest line (shown as bars / mm) passed through the film can be reproduced, determined with vesicular films the smaller the bubble size, the greater the resolution

The results reported above show that the films containing the fluorocarbon had a better one Have resolution. Microscopic examination of these samples showed consistently small bubble sizes · (0.5 μ or less). The presence of the fluorocarbon surfactant also contributes same exposure results in a significant increase in optical density compared to films without dispersing substances or films, the dispersing Contain hydrocarbon-based substances, d. H. the presence of fluorocarbon surfactants increases sensitivity The fluorocarbon-based surfactants used in the present invention differ differ considerably from the hydrocarbon-based surface-active substances previously used for vesicular films, in that the fluorocarbons have very low cohesive energy densities which is reflected in unusually low surface tension and solubility parameters Fer However, the surfaces coated with fluorocarbons have noticeably lower coefficients of friction as hydrocarbon surfaces.

The effects of the fluorocarbons used in the present invention are believed to be based on the following Conditions: The usual organic surface-active substances have aggregation numbers (number of molecules per micelle) from 20 to 150, while surface-active fluorocarbons, on the other hand, have aggregation numbers less than 5. The latter therefore form at least 4 and up to 30 times more in a polymeric binder Micelles as the same amount of a common] surfactant hydrocarbon.

These micelles (agglomerations of surface-active molecules, which with their common ends nac are directed inwards) act as a nucleation point for

709616/161

ίο

the formation of bubbles. Nitrogen in the vicinity during development diffuses into the

(Heat softening level) make the micelles place expanding bladder. The greater the number of micelles

low surface tension, whereby the BiI- and consequently the bubbles in a given system,

The formation of nitrogen bubbles under pressure at these points, the smaller the size of the bubbles and

is favored. When the bubbles expand, the greater the dissolving power of the

the pressure changes, and that in the immediate film.

Claims (1)

Claims: 21 2, 1. Recording material for the vesicular process with a polymeric binder, which is a compound that forms under exposure to nitrogen decomposes, as well as contains a surface-active substance, characterized in that that the surface-active substance is a fluorocarbon of the general formula ι ο