DE1249295B - Thermal copy sheet - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY Int. Cl .:

B 41m

GERMAN

PATENT OFFICE German class: 15 k - 7/05

0 4 1M

EDITORIAL

Number: 1249 295

File number: G 44169 VIb / 15 k

Filing date: July 15, 1965

Opened on: September 7, 1967

The invention relates to a thermal copy sheet, consisting of a base serving as a carrier and heat-sensitive layer applied thereon in a novel composition. This layer contains a component A and a component B, both of which take part in a color-forming reaction. Component A is at least one compound from the group consisting of diphenyl carbazide and derivatives, diphenylcarbazone and derivatives, and diphenylthiocarbazide and derivatives as the component B, metal salts of organic acids. If desired, the coating material can be used another inhibitor for unwanted color formation and also a white pigment together be admixed with a material that melts in heat.

For example, a copy sheet is known which consists of a relatively deeply colored paper and with a white or light colored (almost white) material of suitable melting point is coated. The latter is selectively melted and solidified during the copying process then in a translucent form so that the basic color shines through at these points. There is yet another thermal copy sheet similar to that mentioned above, made of a white-appearing material with a layer of suitable melting point on the back of a semi-translucent paper such as Tracing paper, or a clear sheet such as polyester film, with the layer in turn is covered with color material. When such a sheet is viewed from the front, appears it white or light colored. The surface layer of such a copy sheet is very soft, and the ground color appears even with slight rubbing, and in addition, the layer adversely adheres to the Original sheet during the thermal copying process. The possible carrier material is also on transparent or semi-transparent fabric, d. H. relatively translucent material restricted, and it is also opaque thanks to the colored back.

Finally, there are other heat-sensitive copy sheets that are based on completely different color development principles than the above, for example on the formation of inorganic pigments or the formation of diazo dyes or the color development of light metal salts by chemical reaction due to melting in heat, etc. In some cases, the chemical reaction proceeds with color formation continued in storage. Others are very sensitive to sweat from the hands and light rubbing, and lack out of- £ 0 -T ^
Thermal copy sheet

A 03-6 ^ r

Applicant:

General Company Limited, Osaka-shi (Japan)

Representative:

Dipl.-Ing. H. Fecht, Dipl.-Ing. P. G. Blumbach

and Dipl.-Phys. Dr. W. Weser, patent attorneys,

Wiesbaden, Hohenlohestr. 21

Named as inventor:

Kaneo Fukawa, Osaka-fu (Japan)

Claimed priority:
Japan July 17 , 1964 (40 150),
dated June 18, 1965 (36 016)

sufficient resistance to sunlight or ultraviolet from fluorescent lamps or require a fixation after printing. Also, the copy sheet is unfavorably colored in the original, and the color of the resulting image is not desired. So have the conventional heat-sensitive copy sheets various disadvantages depending on the nature of the composition of the heat-sensitive copying layer.

In contrast, the thermosensitive copy sheet according to the present invention has the merit that it solves all the difficulties mentioned above. The color of the copied imprint can be any Be kind, e.g. B. dark purple. The main feature of the present invention is based on the previously known Technique in that the heat-sensitive mixture contains at least one component from the group Diphenyl carbazide and derivatives, diphenyl carbazone and derivatives, and diphenyl thiocarbazide and its Derivatives as component A and one or more metal salts of organic acids as component B contains.

Diphenyl carbazide and its derivatives according to the present invention have the general formula

Ar — NH-NH-C —NH-NH-Ar (1)

wherein Ar is an aryl group that substitutes in the nucleus

709 640/474

3 4

or can be unsubstituted and the salts of the organic acid with one another show, depending on the metal

can be identical or different from one another. different colors and also different melting

Also diphenylcarbazone and its derivatives according to points, depending on the type of metal and the one used

Invention have the general formula acid. As described above, the precipitations are

5 such metal salts of organic acids are preferred

Ar-NH-NH-C-N = N-Ar (2) white or light colored to white in terms of

jj current practice for heat-sensitive copiers

O scroll. If, however, the natural color of a precipitate is quite dark, it can be without disturbance in which the Ar group is defined as above. io may be used, provided that the opposite

Finally, diphenylthiocarbazide and its between the color of the metal salt in the coating

Derivatives the general formula of a copy sheet and the color used in the

Reaction with component A is developed,

Ar - NH - NH - C - NH - NH - Ar (3) is large enough to separate the two from each other Il 15 differentiate. What the melting point of the metal

S salts of organic acids are concerned, this can be in

Dependence on the type of metal and the type

in which Ar is as defined above. the organic acid can be changed. Demented

The other component involved in the color-developing reaction, speaking of the only problem in the manufacture, is a metal salt of one of 20 combinations that have a melting point of organic acid. There are many metallic elements that give about 50 to about 170 ^° C., which represents a preferred temperature range for color development which react with the above-mentioned component A, heat and coordination compounds among color development-sensitive copy sheets. Hence the development of education. Among them, metals which cause the types of the metal and that of the organic acid to produce a desired color development in copying to produce a preferred combination and to give a good copied image as the object of the present not particularly limited except for the invention are, for example, strontium, the melting point. In the case of a desired lowering of the melting point of the metal salt of a cadmium, lead, tin, copper, iron, cobalt, nickel, organic acid, one or more free organic manganese, molybdenum, bismuth, varium, etc. Organic acids with suitable melting points, the example salts of these metals, have a particular crystal structure that is chemically identical or of different types, such as shape and color depending on the metal. Some of the acidity of the metal salt are white, some of them lighter and some of them are more suitable for the purpose of lowering the melting point of a comparatively dark color. Meanwhile, the principle of melting point depression of Mi-appearance often becomes light colored when they are added in a thin layer. Thus, it is possible to use for the copy sheet, the appearance of color development of heat-sensitive copy sheets is often light colored, and the contrast is not reduced thereby to effect at relatively low temperatures, if a fairly deep colored one and thereby increase the sensitivity.
Material on a surface in a thin layer about Practically are the main components of the heat-1 to 10 μ thick is applied. For this reason, 4 "sensitive copy sheet according to the present invention, the metals to be used according to the invention, the components A and B, as determined above because of the metal salt paint, are not used properly. When preparing a laminate for limited application to a substrate such as paper or film,

In the present invention, one of the following meticulous procedures is preferably used

uses organic acid, its metal salt between 45 and obtaining better copy sheets. Since component A

about 50 and 170 ⁰ C melts. As is known, it is considered one of the color-forming substances in organic

Melting point is not only soluble in the nature of organic solvents such as alcohols and the like,

Acid, but also largely from the metal, causes the completely or partially dissolved compo-

flows. In view of this use, A denotes the color formation even if the metal salt

are the metal salt-forming organic acids 5 ° of the organic acid (component B) is insoluble.

preferably aliphatic carboxyl compounds with This is the so-called "useless" color formation. It

8 to 24 carbon atoms. These are, for example, there are various methods of preventing useless

Caprylic, pelargon, capric, lauric, myristic, color formation. One of them is education

Palmitin-, stearin-, margarin-, arachnin-, behen-, separate partial layers with component A and B respectively

Lignocerin, oleine, elaidic, eruca and cetolein 55 on a pad. In this case it becomes a liquid

acid, etc. binder dispersion of component B to a

The metal salts of organic acids are applied from the base and dried. Then it will be

the aforementioned metals and organic acids like the previously applied layer with a liquid

follows prepared ^ For example, one sets the orga- binder dispersion of component A coated,

nical acids caustic soda in for neutralization from ^6o whereby the binder used for component A

sufficient amount and as much water as different from that used for component B.

Solution is sufficient and the mixture is heated to one. This binder is preferably such that

Temperature close to the melting point of the acid in order not to or only around the previously applied binder

to obtain an aqueous solution. To the resulting little influenced and the layer of component B

aqueous solution one adds the aqueous solution of the ⁶ S protects, ie, it is desirable to use a solvent

inorganic salt to be used in an equivalent amount, whose dissolving power differs from that in the layer

and receives the metal salt of the organic acid different from that of component B and its binder

is insoluble in water. The precipitates of the metal is and also for a heat sensitive copy sheet

5 6

is suitable (ie relatively high melting hydroxycarbonyl acids and their salts, such as glucon point or softening point and high through-acid, citric acid, tartaric acid, malonic acid, sugar permeability for infrared light). A binder solution, acid, sodium citrate, potassium citrate, potassium tartrate, which meets the above-mentioned conditions, is used as ammonium malonate, sodium malona ^ carboxymethyl dispersant for component A, applied to 5 thiosuccinic acid, Schiff bases, organic phosphate, the previous layer and phosphate, 2 thenoyl trifluoroacetone (TTA), 2 thienyl dried. The end result is a metal salt of a 4,4,4-trifluoro-l, 3-butadione, amino acids, etc. You organic acid (component B) in the lower layer can be used individually or in a mixture of two or layer and component A in the upper layer several be used.

contained so that white or light-colored, almost io If the above-mentioned chelates as an inhibitor

white, heat-sensitive copy sheets can be used without useless unnecessary color formation

Color formation can be produced. If this heats the coating material about 1 week after

sensitive copy sheets using a production stand with only slight color change -

Infrared copier can be used. In the manufacture and immediate supply

the partial heating of parts of the letter in the processing of the coating agent does not occur

Original sheet is initially disturbed by the infrared rays. To prevent useless color formation

A melting of component B in the lower is also the choice of solvent for that

Layer of the copy sheet that is in intimate contact coating agent in addition to the aforementioned two

with the original sheet stands, whereupon the melted methods are very effective. As a binder solvent

Component B contact with particles of the composite is therefore used, for example, aliphatic

nent A in the upper layer under immediate off- hydrocarbons, n-heptane, η-hexane, petrol

the course of the color-forming reaction and sharp, etc., which are very effective for this purpose.

Provides images of good contrast. The preparation of the coating agent is the

The sub-layers can also be reversed the same as mentioned above. The main ingredients A

Order are applied, d. that is, the components 25 and B are separated in separate ball mills

Component A then lies in the sublayer and together with the binder solution and an inhibitor

Component B in the outer layer. The resulting unnecessary color formation is ground until it is fine

Copy sheet is almost the same as that after particles form in a homogeneous dispersion. she

The method described immediately above are only established immediately before the application of the

posed. As mentioned above, some metal salts are combined with ready-to-use coating agents. Here

organic acids relatively deeply colored. The undesirable color formation is extremely small, and

therefore, of the components A, the resulting copy sheet is desired to be excellent

and B the appearance with the lighter color as the outer layer. In particular, one is by coating

is applied to copy sheets of lighter color obtained from paper and subsequent drying

and exquisite appearance. 35 Copy sheets from ordinary letterhead

Since the color development at the melting point can hardly be distinguished in appearance,
of the organic metal salt begins, it is preferable to pull the organic metal salt into the sub-layer; the binder solution described above is not crucial; well-known binders can be misplaced in order to turn the holding devices used. Examples include gelatin, polyvinyl and machines to keep clean. Also, a thermal alcohol, polyvinyl butyral, polyacrylic acid ester, poly-sensitive copy sheet with an organic acrylamide, polyvinyl acetate, polyvinyl chloride, poly metal layer is closer to the original, i.e. in contact styrene, methyl cellulose, ethyl cellulose, acetyl cellulose with the base, with regard to the direction of the loose , Polyamide resin, petroleum resin, terpene resin and SiIi heat transfer in the frequent case of the reflex con resin. These binders can be preferred by dissolving into prints. However, if tracing paper, suitable solvents are used, e.g. B. parenter film, etc. are used as a base, so in water, in alcohols such as methyl alcohol, ethyl, the order of the front and back alcohol, isopropyl alcohol and the like. In ketones, such as a copy sheet are just reversed. However, when acetone, methyl ethyl ketone, methyl isobutyl ketone are applied with a protective layer, and the like, in esters such as ethyl acetate and the like, the situation is basically the same as above. / 50 table hydrocarbons, such as hexane, heptane,

Instead of separate sub-layers for the grain petrol, halogen compounds such as methylene

Components A and B can also be an inhibitor chloride, benzyl chloride and the like, and aromatic

for useless color development, together with hydrocarbons such as benzene, toluene, xylene

two components in a single coating and the like.

The use of these means are combined, thereby simplifying the structure of the copy sheet prepared in accordance with the above procedure. The inhibitor coating agent on paper in a thin layer of unnecessary color development prevents the reaction, you get an excellent between the components A and B, with the exception of the copy sheet, which hardly differs from normal paper when heated, completely or delayed for a long time, easy to handle is and good time off. As inhibitors of useless color formation, 60 will see and have a grip. Other metal chelates can also be preferred as carriers, ie substances which have a single film, e.g. B. cellophane foils, also polyester, poly closing compound with a metal ion. As carbonate, polystyrene, cellulose acetate, polyvinyl metal chelates, i.e. substances that are easily used with a chloride film, etc.
Metal react to form a chelate compound, it is also advisable to use a white pigment and as effective examples are aminocarboxylic acids to name a heat-melting material along with, such as. B. EDTA (EDTA = ethylenediamine- the above-mentioned separate spreads for the tetraacetic acid), nitrilotriacetic acid, dihydroxyethyl components A and B or together with the blycine, hydroxyethyl ethylenediamine tetraacetic acid, common spread from components A.

7 8

and to use B and inhibitor to produce an aging rial that satisfies these conditions, for example

to suppress, so the long-term stability to he an organic compound with both hydrophilic

heights and also about the available contrast in as well as alcoholophile groups (including the

to improve the copy. Case that a group has both properties).

The usual heat-sensitive copy sheets 5 examples are acetanilide, aceto-o-anisidide, are quite fickle, they are during normal acetamide, o-aniside, o-aminobenzyl alcohol, p-ami use or in aging sub-nobenzyl alcohol, ethyl urea, / S-elaostearic acid, thrown, and it occurs especially after long periods of time / 9-hydroxyglutamic acid, o-hydroxybenzyl alcohol, a serious deterioration in copy sheets m-hydroxybenzyl alcohol, coumarin, glycolic acid, diein. For example, the copy sheet has white or io aminotoluene, d-monoethyl tartrate, semicarbacid, dark colored, almost white appearance, but occurs more directly with oxybenzoin, / J-m-tolylhydroxylamine, o-bis-hydroxydirect Irradiation by sunlight or during methylbenzene, pimelic acid, phenylacetic acid, / 3-Phedes Thermal copying spontaneously color formation on and nylhydracrylic acid, benzylphenylcarbinol, p-benzyl changes the appearance of the copy sheets. phenol, benzhydrol, benzoylacetone, benzoyl ant

Considering the nature of the thermal copier system 15 acid, homocatechol, methylurea, phthalic acid

was previously from the carrier substrate of the copier anhydride, stearic acid, ceryl alcohol, behenic acid,

leaf requires that it has a background of high palmitic acid, margaric acid, cuajacol carbonate, etc.

Infrared transmittance forms and a color of one or more of the above pigments

high contrast with the thermal image. The after and also one or more of the ones in the warmth

therefore, part was that highly transparent and proportionate 20-melting materials are used. The relationship

moderately thin white paper, e.g. B. tracing paper and a white pigment to form a

Tissue paper, used in practice and on the back - the fabric is not particularly critical, but is available -

side a white layer had to be applied. preferably at 1: 0.2 to 1: 1.5.

In contrast, white pigment is now used in So the heat-sensitive copying sheet according to

used in large quantities (e.g. 2 to 50 pieces of invention stored before or after copying

parts by weight of white pigment per part by weight of color can be removed without this under normal conditions

winding connection), the coating agent itself gradually begins to undergo a critical change,

to make it opaque. Therefore, even when used below, the invention is based on examples

a highly transparent carrier, as described as a completely play. In the examples are everything

clear film and a translucent 30 parts by weight.

Tracing paper, the product after coating Example 1
a white background to keep the thermal image sharp

to press. The main effect of adding the liquid suspension A is prepared as follows:

white pigment is that a large amount of 1.9 parts petroleum gum will be in 94.3 parts petroleum

white pigment which spontaneously, d. H. useless, developed 35 dissolved gasoline for the production of a binder solution. the

Can hide color. So it is possible to copy sheets to the resulting binder solution with 1.9 parts of di-

improve the spontaneous color formation (Verphenylcarbazid and 1.9 parts of stearic acid mixed

discoloration) of the subsurface if it is used for a long time and around 10 hours using a por-

Time to be stored. The combination of color cellular ball mill dispersed. Then the liquid

of the background, of the depth of the copied image and 40 suspension B by dissolving 1.8 parts of petroleum

of degree of spontaneous color formation, i.e. the total of gum prepared in 93.6 parts of petrol, 4.6 parts

existing contrast, leads to very good copies. Mercury laurate added and then 10 hours in

Possible white pigments are, for example, dispersed in a porcelain ball mill. The received

white zinc, white lead, titanium oxide, lithopone, suspension liquids A and B are mixed,

Alumina white, calcium carbonate, carbon white 45 on a white paper approx. 40 μ thick.

(white carbon), antimony white, basic lead sulfate, wear and at room temperature, but not higher than

Lead silicate, zirconium oxide, tin oxide, barium sulfate, Ba- 50 ⁰ C dried. The sheet thus obtained is white

rium carbonate etc. and creates a deep dark purple image when

As mentioned above, the sheet and a sheet of paper are melted together in heat and then copied together with the white pigment.
is working. The heat-melting material prevents the tendency that the depth of color of the heat
due to the light-diffusing property of the _. ^ ₁ .. ,, ■ ~ ·· · 1 ^ λ
Thermal image, due to the use of white recipe for Suspensionsflu _SS1 ness A:

pigments is reduced, and leaves the heat 55 diphenyl carbazide 1.9 parts

image appear clear. The fact is tartaric acid 0.5 parts

based on the fact that this material was 0.9 parts sodium nitrate during color development

the heat applied melts the colored stearic acid 1.9 parts

Dissolve forming components in it, thereby the ethyl cellulose 3.8 parts

color-forming reaction is accelerated and also 60 methyl ethyl ketone 91.0 parts

the resulting color compound dissolves in it, thus recipe for suspension liquid B:

the opaque effect of the white pigment compensates for copper stearate 3 6 parts

and gives sharp images. The ethyl cellulose in question '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.'. 5 ^ 4 parts

Coming materials are organic compound methyl ethyl ketone 91.0 parts

fertilize with a melting point between about 60 65

and about 130 ⁰ C, which in the molten state with The aforementioned two mixtures are in

the color-forming components and treated therefrom in the same way as in Example 1 and form

The color compound formed are miscible. A mate- the suspension liquid A and suspension liquid-

speed B in which the fine particles are homogeneously dispersed. Then the two suspensions are mixed, applied to a white paper about 40 μ thick and dried ^{at room temperature, but not higher than 50 ° C.} The sheet obtained in this way is bluish, but almost white. During thermal copying, a deep, dark purple image of a line drawn on the original paper appears at the corresponding point.

Example 3

Recipe for suspension liquid A:

Diphenylcarbazone 1.9 parts

Tartaric acid 0.9 parts

Ethyl cellulose 2.8 parts

Methyl ethyl ketone 94.4 parts

Formula for suspension liquid B:

Zinc laurate 2.8 parts

Ethyl cellulose 2.8 parts

Methyl ethyl ketone 94.4 parts

The aforementioned mixtures are treated according to the procedure of the previous example. The sheet obtained in this way gives an image in reddish purple on thermal copying.

Example 4

Recipe for suspension liquid A:

Diphenylthiocarbazide 1.8 parts

Sodium tartrate 0.9 parts

Polyvinyl butyral 8.9 parts

Methyl alcohol 87.0 parts

Recipe for suspension liquid B:

Calcium oleate 2.6 parts

Stearic acid 1.7 parts

Polyvinyl butyral 8.7 parts

Methyl alcohol 87.0 parts

A dark green image is obtained on heating a sheet made with the two above mixtures is dealt with if one works according to the procedure of the previous example.

30th

35 Prepared methyl alcohol for the preparation of a binder solution to which 1.8 parts of diphenylthiocarbazide and 1.8 parts of stearic acid are added and which, by grinding for 10 hours in a porcelain ball mill, gives a homogeneous dispersion of fine particles. The suspension liquid A obtained in this way is applied to a white paper approximately 40 μm thick and dried at a temperature not exceeding ^{50 ° C.} Suspension liquid B is then prepared separately by dissolving 1.9 parts of petroleum gum in 94.4 parts of commercial petrol, then 3.7 parts of bismuth palmitate are added and the resulting mixture is ground in a ball mill for 10 hours to form a dispersion of finely divided particles. The dispersion thus obtained is coated on a layer A produced beforehand with liquid A and the suspension was dried at 50 ⁰ C temperature not exceeding. The image color produced when the sheet is heated is brown.

Example 7

Recipe for suspension liquid A:

Diphenyl carbazide 1.8 parts

Stearic acid 1.8 parts

Methyl cellulose 2.7 parts

Water 4.5 parts

Methyl alcohol 89.2 parts

Recipe for suspension liquid B:

Iron stearate 2.7 parts

Sodium citrate 0.9 parts

Methyl cellulose 2.7 parts

Water 4.5 parts

Methyl alcohol 89.2 parts

40

Example 5

Recipe for suspension liquid A:

2,2'-dimethylphenylthiocarbazide 1.9 parts

Petrol gum 1.9 parts

Petrol 96.2 parts

Recipe for suspension liquid B:

Cadmium stearate 2.8 parts

Stearic acid 1.8 parts

Petrol gum 1.8 parts

Petrol 93.6 parts

45

55

An orange image is obtained when a sheet is heated when mixed with both of the above mixtures treated according to the procedure of the previous example.

Examples

In the present example no inhibitor of useless color formation is used and the color-developing one Layer is constructed in such a way that it consists of two layers. The suspension liquid A is by dissolving of 2.8 parts of ethyl cellulose in 93.6 parts of that when the sheet is heated according to the above The color resulting from the above two mixtures is reddish brown in the method mentioned in the example.

Example 8

Recipe for suspension liquid A: 2,2'-4,4'-tetramethyl-

diphenylcarbazone 1.9 parts

Stearic acid 1.9 parts

Petrol gum 1.9 parts

Petrol 94.3 parts

Recipe for suspension liquid B:

Cobalt stearate 2.9 parts

Petrol gum 1.9 parts

Petrol 95.2 parts

The image color that results when you heat one with the above mixes according to the previous example forms is deep purple.

Example 9

Recipe for suspension liquid A:

Diphenylthiocarbazide 1.8 parts

Tartaric acid 0.5 parts

Stearic acid 0.9 parts

Sodium citrate 0.9 parts

Ethyl cellulose 3.7 parts

Methyl alcohol 92.2 parts

709 640/474

Recipe for suspension liquid B:

Nickel palmitate 2.8 parts

Stearic acid 0.9 parts

Ethyl cellulose 3.7 parts

Methyl alcohol 92.6 parts

The color of the image resulting from the heating of an image when treated with the above mixtures The sheet that forms after the procedure in the previous examples is blackish Brown.

Example 10

Recipe for suspension liquid A:

Diphenylthiocarbazide 1.8 parts

Citric acid 0.5 parts

Sodium citrate 0.9 parts

Polyvinyl butyral 8.8 parts

Methyl alcohol 88.1 parts

Recipe for suspension liquid B:

Aluminum stearate 4.4 parts

Polyvinyl butyral 8.7 parts

Methyl alcohol 86.9 parts

The color of the image that resulted from the heating of one after treatment with the above mixtures The leaf formed after the procedure of the previous examples is a dark green.

35

Example 11

Recipe for suspension liquid A:

Diphenylthiocarbazide 1.9 parts

Citric acid 0.5 parts

Sodium citrate 0.9 parts

Ethyl cellulose 2.8 parts

Methyl alcohol 93.9 parts

Recipe for suspension liquid B:

Lead palmitate 2.8 parts

Ethyl cellulose 2.8 parts

Methyl alcohol 94.4 parts

The color of the image that resulted from the heating of one after treatment with the above mixtures The leaf formed by the procedure of the previous examples is carmine red.

Example 12

Recipe for suspension liquid A:

Diphenyl carbazide 1.9 parts

Methyl cellulose 2.9 parts

Methyl alcohol 95.2 parts

Recipe for suspension liquid B:

Mercury Palmitate 4.6 parts

Methyl cellulose 2.8 parts

Methyl alcohol 92.5 parts

The suspension liquid A is made by dissolving methyl cellulose in methyl alcohol for preparation a binder solution prepared, the resulting binder solution mixed with diphenyl carbazide and Dispersed in a ball mill for hours. Then the suspension liquid B is made by dissolving Methyl cellulose prepared in methyl alcohol, added mercuropalmitate and put in the ball mill for 10 hours dispersed.

These suspension liquids A and B are stirred together to form a combined dispersion liquid, which is then mixed with the following dispersion liquid C and applied as indicated below will.

Recipe for suspension liquid C:

Water 48.2 parts

Titanium Oxide 28.8 parts

Palmitic acid 19.2 parts

Citric acid 1.9 parts

Sodium citrate 1.9 parts

The suspension liquid is prepared by stirring for 2 hours the above ingredients at 25 ⁰ C.

The aforementioned suspension liquids A, B and C are mixed to form a layer substance which on a base, e.g. B. a sheet, according to one of the various application methods such as rolling, pressing, Spraying with an air jet, transfer printing

ao u. the like., and then dried in air at room temperature, but not higher than 50 ⁰ C. The sheet obtained in this way is white or light in color, and the bluish-red image of an original document produced during thermal copying is in clear contrast to the white or slightly colored background and is very sharp.

One must note that a heat-sensitive copy sheet, which can only be obtained from the suspension liquids A and B obtained without suspension C according to the above-mentioned procedure (Example 12), with respect to long shelf life and sharpness of the image on a highly transparent base is not satisfied.

Example 13

Recipe for suspension liquid A:

Diphenylcarbazone 3.7 parts

Methyl cellulose 2.8 parts

Methyl alcohol 93.5 parts

Recipe for suspension liquid B:

Mercury behenate 4.6 parts

Methyl cellulose 2.8 parts

Methyl alcohol 92.6 parts

Recipe for suspension liquid C:

Water 38.7 parts

Antimony white 31.0 parts

Ethyl urea 23.2 parts

Tartaric acid 1.6 parts

Behenic acid 3.9 parts

Sodium tartrate 1.6 parts

The above ingredients are treated in the same way as in Example 12. The color of the The resulting heat-sensitive image is deep purple when heated.

Example 14

Recipe for suspension liquid A:

Diphenyl carbazide 3.7 parts

Polyvinyl butyral 4.6 parts

Methyl alcohol 91.7 parts

Recipe for suspension liquid B:

Copper behenate 4.55 parts

Polyvinyl butyral 4.55 parts

Methyl alcohol 90.9 parts

Claims (3)

13 14 Recipe for suspension liquid C: The above ingredients are in the same Polyvinyl butyral. 4 2 parts way treated as in Example 12. The color of the Methyl alcohol 830 parts of the resulting heat-sensitive copy sheet Titanium Oxide ... .VVVV '.'. '.'. '.'. '. 66> Parts of heating is deep P ur P ure red - Behenic acid 2.4 parts 5 claims: Acetamide 41.4 parts,. , t . . .. Tartaric acid 1 8 parts thermal copy sheet with a heat-sensitive Sodium citrate '.'. '.'. '.'. '.'. '.'. '.'. '.'. '.'. '. o's parts union Λ ^ S h, maybe 'da, characterized d for u ^ c that the latter as color-forming components The above components are in the same io at least one body from the group diphenyl Way treated as in Example 12. The color of the carbazid, Diphenylcarbazon and Diphenylthio- by heating the heat-sensitive copy sheet carbazon or their derivatives as well as at least is deep purple. contains a metal salt of an organic acid. 2. thermal copy sheet according to claim 1, characterized B e i s ρ i e 1 15 15 characterized in that the heat-sensitive " A ... η · a- ■ 1 · λ layer as inhibitors of undesired color formation Recipe for suspension fluid A: Serving substances are added> the mh dnem Diphenyl carbazide 1.9 parts metal ion form inclusion compounds (chelates). Petroleum gum 2.9 parts 3. thermal copy sheet according to claim 1 or 2, Petroleum benzine 95.2 parts 2 o characterized in that in the heat-sensitive Recipe for suspension liquid B: borrowed layer a white pigment together with Mercury palmitate 4.6 parts melted in heat between 60 and 130 ° C Petrol rubber 2 8 parts zenden material is mixed in, which is in the Petrol 926 parts molten state with the color-forming '' 25 components and the resulting color Recipe for suspension liquid C: shock mixed. Petroleum gum 6.6 parts Petrol 215.7 parts Publications considered: Titanoxide 43.2 parts German Patent Nos. 878 806, 1149 730; Stearic acid 34.5 parts 30 German Auslegeschrift No. 1 151 784. 709 640/474 8. 67 Q Bundesdruckerei Berlin