CS225005B1 - The radiation-sensitive material - Google Patents

Description

The invention relates to a radiation sensitive material consisting of a photochromic organic compound, a binder and a carrier.

Photochromic materials are used for various purposes such as recording optical signals, protective film, optical filters and switches. '

However, the materials used so far have various disadvantages. Color forms of photochromic compounds often provide low extinction coefficients, i.e., sufficiently saturated colors are not obtained at the desired low layer thickness.

Often, sufficient stabilization of the materials due to thermal reversal reactions is also not possible. Good image stabilization is achieved only by fixation after it is created, however, the possibility of reversibility is lost.

Another disadvantage of the materials used so far is that they are only suitable for the negative-positive process. However, it is often necessary to create positive copies of positives, such as in the reproduction of microfilms and transparent painted artwork. With many photochromic materials, production is demanding and associated with high costs. Color changes over a wider spectrum are not always achieved by small changes in the structure of the photochromic compound.

Heterocyclic formazanes of the formula> - $! <>

where

X = S, O or NR

R = alkyl or aryl,

Y = II, an alkyl group or a halogen atom,

They are known in the literature as photochromic materials, see Soviet Patent 241,442. The potochromic effect of these compounds is obtained only when formazan is dissolved in solutions of CCl and CHCl3 and is only weak in other liquids. This formazan cannot be used in solid layers.

The purpose of the invention is to produce a light-sensitive material which, by virtue of its production and properties, is well usable, allows the production of positive copies and can advantageously be used as a reversible or irreversible recording material.

IN

The invention provides a light-sensitive system that is supported on a suitable carrier and which provides visible or UV irradiated or irreversible positive images of higher color saturation, without the need for further processing.

The above-mentioned drawbacks have no radiation-sensitive material containing photochromic compounds, which is based on the fact that it contains formazanes of the general structural formula as photochromic compounds.

NN R ¹ -CQH

NN \ r ³ in which, 1

NN II R ¹ - /

R ^J stands for / ^r

-ςυψ

N-N

N— N

PR o PR ^{1 —} — N □ 2 'or

/ ^r

III (tl — N N — N

HO / ^{C_X_ («} O /

N — N

N — N ^ R ³ heterocycles (azole, benzazole, furyl-)

X>. . í>

R stands for hydrogen, nitro, halogen, phenyl, R ', NRg »COOR'

Y denotes > ®2 '>> 1 · - ^{CH = CH} X denotes -CHg-, - <o> 3

O

RO OR '

R * denotes hydrogen, lower alkyl (methyl, ethyl), benzyl,

Preferably, the radiation-sensitive material of the present invention further comprises a binder such as polystyrene, polyvinylbutyral, nitrocellulose, cellulose acetate, polyvinyl chloride, polyvinyl acetate, polyacrylate, polycarbonate, polyamide and polymethacrylate, wherein both the photochromic compound and the binder are supported.

The radiation-sensitive material of the invention preferably comprises a photochromic compound dissolved in solvents such as toluene, benzene, o-, p- and n-xylene, carbon tetrachloride, chloroform, methylene chloride, 1,2-dichloroethane, ethyl acetate, butyl acetate, methyl acetate, n. heptane, n-hexane, 1,4-dioxane, methyl ethyl ketone, methyl isopropyl ketone, methyl isobutyl ketone, ethyl acetate and benzoylacetic acid ethyl ester.

The radiation-sensitive material of the invention is suitably applied to the support by forming a polymeric film, such as polyester film, cellulose acetate film, post-chlorinated polyvinyl chloride film, paper or glass plate.

The advantage of the material according to the invention is that it represents an optimal recording medium based on relatively available formazans. This material allows a reversible or irreversible process to be carried out as required.

Equation 1 describes in simplified form the photochemical reaction of formazans:

h.Vg X-A - h. ^ ₂ -Β (1) (λ ₃ > (λ,) maximum absorption ingredients applies: λ3 <λ2 <Al h 9 ₂ > hV, - radiation energy for irreversible and reversi-

bile photoreaction £ - thermal feedback

Obviously, formazan (A) can produce two different photoreactions by different radiation energies. The first is reversible photoisomerization, stimulated by the energy of the long wave radiation, to obtain the isomer (B). The feedback reaction takes place on a thermal basis.

The second reaction is irreversible photoaxidation to tetrazolinyl cation (X) by radiation of short wavelength, such as UV-radiation.

Depending on the substituents and type of the formazone system, the components achieve the following coloring:

X = orange ..... red ..... purple ..... blue

B = yellow ..... orange

X = colorless ..... yellow

The coloring, and in particular the kinetics of the thermic back-reactions can be influenced by encapsulating materials such as polymeric binders and solvent when used in the liquid phase.

The photochemical reactions of the formazene-binder system also affect other ingredients.

Acidic or basic additives are generally a defect to reduce the rate of thermal reactions.

When working with unfiltered mercury lamp light, allowing only the reversible reaction of A-B *, a UV-absorbing substance such as hydroxylbenzophenone is added to the system.

If, on the other hand, an irreversible reaction is required (A ---- * X), a slightly oxidizing agent is used. Optionally, this can first be achieved by irradiation.

The radiation-sensitive materials are prepared by mixing photochromic compounds with a polymeric binder, such as polystyrene, polyvinyl butyral, nitrocellulose, cellulose acetate, polyvinyl chloride, polyvinyl acetate, polyacrylate, polyamide and polymethacrylate, and poured onto the substrate. The substrate used is a polymer film, a cellulose acetate film, an additionally chlorinated polyvinyl chloride, a paper or a glass plate.

Irradiation or pictorial illumination of the material causes the reaction of the substances according to the invention.

The light-sensitive material used in the liquid phase is prepared by mixing the compounds of the invention in cuvettes. Solvents which may be used are, in particular, toluene, benzene, o-, p-, m-xylan, carbon tetrachloride, chloroform, methylene chloride, 1,2-dichloroethane, ethyl acetate, butyl acetate, n-heptane, n-hexane, 1,4-dioxane, methyl ethyl ketone, methyl isopropyl ketone, methyl iso butyl ketone, ethyl acetate and banzoylacetic acid ethyl ester.

The material according to the invention makes it possible to obtain optimum recording media based on relatively readily available formazans.

The recording material makes it possible to carry out a reversible or irreversible process and, as required, a simple conversion of the radiation sources by exchanging upstream filters.

The reversible operation is particularly suitable for making working copies and intercopters.

After thermal erasure, the material can be reused. For reversible filters, formazans in dissolved form are used; in a cuvette.

A particular advantage of irreversible operation is the high storage stability of the illumination material. Recording is only made on ultraviolet radiation corresponding to the image, without the additional fixation process. The material is an instant image.

When formazans are used as light-sensitive components, the color tone of the image of an existing record may vary within wide limits of the type and substituents of the formezan base. For this reason, high densities and hence sharp contrasts are possible.

The following examples illustrate the invention.

Example 1

The formazams listed in Table I are dissolved in o-xylene and used in cuvettes of 1 cm thickness. Concentration is 10 ^- to 10 ^ ^- ^ mol / liter. Subsequently, a single-hollow irradiation with a mercury high-pressure lamp is carried out, which is preceded by an infrared filter and a 744 filter. The solution temperature is 25-30 ° C.

Table 1 summarizes the reactions of individual structures (»

Table X

Try C. Granary ^R 1 R ² -, - R ^J X r ' Colorful change 1. AND pR ₂ NC ₆ ^H 4 ^C 6 «5 ^C 6 ^H 5 ch ₃ purple 2 AND pR OCgH ₄ ^C 6 ^H 5 ^C 6 ^H 5 ch ₃ yellow-orange- žové burgundy-yellow 3 AND _p -o _{2 6} h ₄ ^C 6 ^H 5 c ₆ h ₅ - orangeheart- the 3 11 pr-nc ₆ hours ₄ ^C 6 ^H 5 - ΧθΜΙλ ch ₃ blue-yellow / \ R'O OR ' 3 III - ^C 6 ^H 5 p-r'occ ₆ h ₄ ^CH 3 burgundy-yellow

The half-life of the thermal reaction is 20 minutes to 3 hours.

Example 2

2 3

The tris- (p-tolyl) formazan of formula I wherein R, R, R is CH ^C ^H H is dissolved in the solvents listed in Table II, then introduced into cuvettes of 1 cm thickness and heated in accordance with Example 1. The concentration of the solution is 10 ^- 10 to 10 lit mol / liter.

Table II

Focus no

Solvent

Color change

Half-life of thermal feedback

O-xylol

1,4-dioxane

1,2-dichloroethene burgundy-yellow burgundy-yellow burgundy-yellow h

more hours 1/4 hour

Example 3

The triethyl (p-tolyl) formazan is mixed with the binder shown in Table III, poured onto polymer films or glass plates and irradiated as in Example 1. The irradiation time is 3 minutes and the weight ratio of formazan and binder is 1:50 to 1: 100 ALIGN!

Table III

Example # Binder Color change Half-life of thermal feedback 9 nitrocellulose red-yellow 1 h 10 polyvinylbutyral red-yellow 1 h 1 1 polystyrol red-yellow 1 h

Example 1 and d 4

The procedure was performed analogously to Example 3. Only the filter 744 on the radiation source was replaced by the filter 601. The results are shown in Table IV.

Experiment no. Binder Color change 12 nitrocellulose red-colorless 13 polyvinylbutyral red-colorless 14 polystyrol red-colorless

Stability in ultraviolet light distribution with ultraviolet radiation at least 6 months.

Example 5

The iris- (p-tolyl) formezan is mixed with the 8 binders listed in Table V and poured onto a paper backing. Subsequently, the illumination corresponding to the image is carried out by means of a transparent drawing of the technical drawing.

Table 5.

Example # Ppjivo Change of color 15 Dec polyvinylbutyral red-yellow Enable thermal erasure of the image 16 polyvinylbutyral Red-colorless The image remains

stable in diffuse daylight

Claims (4)

A radiation-sensitive material comprising photochromic compounds, characterized in that the photochromic formazan compounds correspond to the general formulas: R ^{* 1} , R ² , R ³ denote -Z al N ~ O, Pt * rf-c O N ~ N HO cf kN, 2 / ^X R ³ or 1 / N-1 HC-c-x-cfOH-N-N-Ki v R R heterocycles such as azole benzazole, furyl R ' R- O denotes hydrogen, halogen, nitro, phenyl, R ', NR', 'OR', NHR ', COOR', denotes CR ', NR', O, S, -CH = CH denotes -CHg-, R 'R' RO OR ' R 'denotes hydrogen, lower alkyl and benzyl, 2. The radiation-sensitive material of claim 1, wherein the photochromic compounds are mixed with a binder such as polystyrene, polyvinyl butyral, nitrocellulose, acetate cellulose, polyvinyl chloride, polyvinyl acetate, polyacrylate, polycarbonate, polyamide, and polymethacrylate and deposited on a carrier. 3. The radiation-sensitive material of claim 1 wherein the photochromic compounds are dissolved in solvents such as toluene, benzene, ο-, ρ-, m-xylene, carbon tetrachloride, chloroform, methylene chloride, 1,2-dichloroethane; ethyl acetate, butyl acetate, methyl acetate, n-heptane, n-hexane, 1,4-dioxane, methyl ethyl ketone, methyl isopropyl ketone, methylsobutyl ketone, ethyl acetate and ethyl benzoylacetic ester. 4. The radiation-sensitive material of claim 2 wherein the carrier comprises a polymeric film, such as polyester film, cellulose acetate film, post-chlorinated polyvinyl chloride film, paper or glass plate. '