DE2808310B2 - - Google Patents

Description

The invention relates to thermal copying material with improved properties, in particular for Use in thermographic copying, thermal printing, for recording measured values and as a slide for overhead projection. By combination special active ingredient components succeed in realizing previously unrealizable color effects.

Heat-sensitive or heat-sensitizable recording media have already been developed containing ring-shaped polyketo compounds have been used for copying and recording and have the ability to form a record of contrasting color when placed on a Activation temperature of 50 ° C are heated.

The ninhydrinamine reaction, in which ninhydrin is associated with amino acids, primary amines and certain Morpholine, piperidine and pyrrolidine derivatives react, so that it is commonly referred to as Ruhrmann purple Color is well known. Isatin reacts with the same amines to give isatin blue. Alloxan reacts with the amines and creates a red dye. These reactions come in numerous Inventions used for heat-sensitive copies and recording papers and films. In the US-PS 37 36 166 is ninhydrin with various MorphcUn and Piperirlinderivaten for the production of Slides used for overhead projection In US-PS 32 93 061 ninhydrin or hydrindantin is used Isatinamine condensates used to make thermographic, copy sheets. In the US patents 3149 991 and 3149 992 becomes ninhydrin or Hydrindantin with complexes of amines and flavans or phenolic compounds for making thermographic Copy papers used. In the US PS

ίο 36 64 858 becomes ninhydrin with the inclusion compounds of morpholine or piperidine and organic acids used in thermal recording media. In the US-PS 30 24 362 are hydrindantine with amino acids or salts of primary amines with organic Carbonic and sulfonic acids combined to make thermal copy paper in US Pat. No. 2,967,785 the inclusion compounds of morpholine or piperidine with isatin or ninhydrin as color-forming Substance used in thermal copy paper In US-PS 35 73 958 an amine is used with a halide or organometallic halogen of germanium, silicon, lead and tin combined with hydrants for Production of a heat-sensitive recording medium. In all of these cases they were normal

2) color formation of Ruhrmann purple with ninhydrin, red color obtained with alloxan and isatin blue.

However, it is often desirable and is the object of the invention to obtain color records, whose colors differ from those who

jo usually with the aforementioned annular Polyketo compounds are obtained.

During the heat dissociation or decomposition of the complexes, salts or inclusion compounds often undesirable odors during imaging

ij and fumes developed. The problem of fading of the image also arises in the event of excessive heating or aging or due to exposure to light containing UV components for too long.
Attempts to use heterocyclic diimino compounds such as the piperazine derivatives have colorless or very pale images, a general deterioration in coatings or a coating that is due to the highly hygroscopic property of the piperazines and their unpleasantness

4 · ί odor is unacceptable, as a result.

The problems and disadvantages indicated above can be minimized or eliminated according to the invention will. The thermal copying material according to the invention with applied to a carrier heat-sensitive

-> o rather a recording layer based on a synthetic resin binder, which contains a color-producing active ingredient pair, is characterized in that it is as Contains active ingredient pair

1) an N-substituted condensation product of a heterocyclic diimino compound and an aromatic aldehyde, the heterocyclic diimino compound being selected from the group comprising piperazine, homopiperazine, 2-alkylpiperazine and 2,5-dialkylpiperazine, and
^h "2) a cyclic polyketo compound selected from the group consisting of ninhydrin, isatin, 5-bromoisatin, 5,7-dichloroisain, alloxan, alloxazine and hydrindantin.

i. ^r> aldehyde condensation product and the Polyketoverbindung react at temperatures in the range of 50 to 200 ⁰ C and form a number of different intense dyes. The volatility, the smell and

the hygroscopic properties of the original piperazine derivatives are eliminated Preparing the piperazine condensation products are generally cheaper than those for the inclusion compounds and prior art complexes, and the yield is high, making it an inexpensive one Thermal copying material is obtained.

The thermal copying material is produced in a manner known per se. A synthetic resin solution will an N-substituted condensation product of one of the said heterocyclic diimino compounds and an aromatic aldehyde and one of the said ring-shaped polyketo compounds added, and a suitable support is coated with this synthetic resin solution

The N-substituted condensation product is prepared as follows: 1 mole of the piperazine or substituted Piperazine or homopiperazine is made with 1 mole of an aromatic aldehyde in methanol or ethanol Condensed under reflux for 4 to 8 h. The condensation product precipitates on cooling and is filtered off with Alcohol washed and dried If a precipitate does not form immediately, it can form be initiated by adding water to the reaction mixture.

The production of slides will now be explained. The cyclic polyketo compound and the piperazine condensation product are in a binder that is in the form of a solution in an organic solvent present, solved. The binder only acts as a carrier for the active ingredients that react to form color. Any transparent binder, such as acrylic and methacrylic copolymers, cellulose esters, nitrocellulose, Polyvinyl acetates, butyrals, styrene polymers and styrene copolymers, etc., can be used. the suitable solvents include ketones such as methyl ethyl ketone; Alcohols such as methanol; Ester like Ethyl acetate, and aromatics such as toluene. Usually the approaches for the slides are stabilizers added. Usual stabilizers are z. B. in US-PS 37 36 166 given and include substituted ureas and thioureas, such as ethyl urea, n-propyl urea, Allylurea, N-methylthiourea and allylthiourea, gallic acid, o-, m- and p-toluic acids, 2-mercaptobenzothiazole and 2,2'-dithiobis (benzothiazole).

About the sensitivity or heat sensitivity of the recording layers of the thermal copying materials to increase according to the invention, activators can also be used. A simple process for Selection of suitable activators is as follows:

The selected N-substituted condensation product and a cyclic polyketo compound become grind together as a dispersion in an aqueous solution of polyvinyl alcohol by means of a ball mill. The dispersion is then applied to a backing paper and heated on a hot plate. if the color in the area in which additional powder activator was applied, faster developed, the material increases the sensitivity of the system. Some of the particularly suitable activators are given in Table I below.

Table 1

2-marcaptobenzoxazole
2-mercaptobenzothiazole
2.2'-dithiobis (benzothiazole)
2-benzoxazole thiol

2-benzothiazolol

2-MorphoIinthiobenzothiazole

2,4-dichloro-1-naphthol

2-chloroacetamide
o-, m- and p-toluic acids

Thioacetanilide

Thiobenzanilide

Phenoxazine

Phenyl-3-thiocarbazide
ίο N-Cyclohexyl-2-Benzothiazolesulfonamid N-tert-ButyI-2-Benzothiazolesulfonaniid sulfanilamid

4,4'-dithiodimorpholine

1,1,3,3-Tetramethyl-2-thiourea 2,4-thiazolidenedione

Thiazolidenthione

N-methylbenzothiazoa-2-thiourea p-hydroxyacetophenone

1,3-lndandion
Butyl zinc dimethyldithiocarbamate 2,2-dithiobis (benzothiazole)

Chloroacetophenone

3,5-dibromosalic aldehyde

3,4-dihydroxybenzoic acid
Biphenyl

Acetone oxime

Transparent films that can be used as a substrate for slides are, exist z. B. from terephthalate polyesters, jo polycarbonates, polyamides, polystyrene and cellulose acetate butyrate copolymers.

The coatings can be applied by any conventional method, e.g. B. with a Meyer's rod, with counter-rotating rollers, as an abrasive application, etc. j · -, The coating weights of the heat-sensitive coatings are usually within a range from 3.2 to over 16 g / m ² .

The following example 1 shows typical embodiments, di <; as slides for overhead projection are usable.

example 1

Production of slides for overhead projection

Resin solution with the following

there has been a
Prepared composition:

Methanol
Methyl ethyl ketone
Nitrocellulose
Polymethyl methacrylate

Parts

134

386

39

90

Then the following mixtures were prepared:

Mixture "A"

Synthetic resin solution

stabilizer

Lactic acid

Piperazine aldehyde condensate

Mixture "B"

Synthetic resin solution
annular polyketone

Parts

100 1.0 0.7 4.0

142 4

The coating composition obtained from 13 parts of mixture "B" and 10 parts of mixture "A" was applied to a 76.2 μm thick terephthalate polyester film with a Meyer's rod, which was cut with

28 08310 6th Colors projected aldehyde became. Image color 5 became. The dried coated slide was made with. Examples are then given in Table II Wrap around a No. 24 wire was upset and illustrations an infrared light absorbent: specified in contact of compounds necessary for making the original Benzaldehyde Brown showing slide? were obtained, wherein brought and used in the usual way by a thermocouple 5 slides Salicylaldehyde Brown dried so that a transparent film received the images in a variety pier sent. Suitable for overhead projection. 5-nitrosalicylaldehyde Brown Table Il o-chlorobenzaldehyde annular poly- Brown Examples of slides p-chlorobenzaldehyde keto connection Brown condensate Bromosalicylaldehyde Ninhydrin Brown Di'mino connection 3,5-dibromosalicyaldehyde the same Brown 2,4-dimethoxybenzaldehyde the same Brown 1. Piperazine 2-hydroxy-3-methoxybenzaldehyde the same Brown 2. the same o-vanillin the same Brown black : 3. the same. 3,4,5-trimethoxybenzaldehyde the same Brown black ^: 4. the same. Cinnamaldehyde the same Brown 5. the same tf-methoxycinnamaldehyde the same Brown 6. the same p-hydroxybenzaldehyde the same Brown black 7. the same 5-hydroxy-2-nitrobenzaldehyde the same Brown black 8. the same m-nitrobenzaldehyde the same Brown black 9. the same o-nitrobenzaldehyde the same blue black 10. the same. 9-anthraldehyde the same Brown black 11. the same 2-hydroxy-1-naphthaldehyde the same Brown 12. the same p-isopropylbenzaldehyde the same Brown 13. the same p-cyanobenzaldehyde the same Brown 14. the same 1-naphthaldehyde the same Brown 15. the same o-methoxybenzaldehyde the same Brown 16. the same o-ethoxybenzaldehyde the same Brown black 17. the same 6-nitroveratraldehyde the same Brown 18. the same j-ethoxy-4-hydroxybenzaldehyde the same Brown black 19. the same 2,4-dinitrobenzaldehyde the same Brown black 20. the same o-phthalic acid dicarboxaldehyde the same dark blue 21. the same Terphthaldicarboxaldehyde the same Brown 22. the same ρ-Ν, Ν-dimethylaminocinnamaldehyde the same Brown black 23. the same p-chlorobenzaldehyde the same dark brown 24. the same m-nitrobenzaldehyde the same dark brown 25. the same Cinnamaldehyde the same Brown 26. the same 1-naphthaldehyde the same Brown 27. the same m-nitrobenzaldehyde the same Brown 28th the same o-phthalic acid dicarboxaldehyde the same dark brown 29th the same 2-naphthaldehyde the same dark brown 30. the same o-phthalic acid dicarboxaldehyde the same dark brown 31. Homopiperazine p-chlorobenzaldehyde the same Brown 32nd like the same the same Brown 33. the same. the same the same Brown 34. 2,5-dimethylpiperazine the same the same Brown 35. the same. the same 36. the same. Isatin 37. 2-methylpiperazine 5-bromoisatin 38. the same. 5,7-dichloroisatin 39. homopiperazine 5-nitroisatin 40. the same. 41. the same. 42. the same.

continuation

condensate
Diimino compound

aldehyde annular poly keto connection p-chlorobenzaldehyde Alloxan the same Alloxazine o-phthalic acid dicarboxaldehyde 5-nitroisatin the same Alloxan the same Alloxan

Image color

43. homopiperazine

44. the same.

45. 2-methylpiperazine

46. 2-methylpiperazine

47. 2,5-dimethylpiperazine

Red

red-brown

red-brown

red-brown

red-brown

In the context of the invention, preference is given to using N-substituted condensation products which derived from 2-methylpiperazine or 2,5-dimethylpiperazine.

Example 2

Preparation of coated papers for

Thermal copying, for thermal printers and

Recording purposes with heated pen

The piperazine condensation products, the ring-shaped polyketone derivatives and all additives used as accelerators or stabilizers were milled separately. The individual mixtures for the recording layer were prepared by using the components in a 15 percent concentration of a 5 percent aqueous polyvinyl alcohol solution. ^{The mixtures were applied to 40 g / m 2} sulfite-based paper with a Meyer's rod wrapped with # 16 wire. The following examples in Table III indicate the combinations of active ingredients and additives, their proportions, the coating weights and the image colors which were obtained with a thermal copier, a thermal matrix printer and a recording device with a heated pen.

Table III

Examples of coated paper

Piperazine condensate Additive Polyketone Relation weight colour g / m ² 1. Terephthalaldehyde - Kydrindantin 1: 2 2.4 black the same - the same 2: 1 3.7 black 2. the same - Isatin 1: 2 4.4 Brown black 3. the same - Alloxan 1: 2 6.4 red-brown 4th the same - Hydrindantine 1: 4 6.2 black 5. the same p-toluic acid Ninhydrin 1: 1: 2 4.1 Brown black the same the same the same 2: 1: 2 2.4 dark brown the same the same the same 4: 1: 2 2.3 Brown the same the same the same 8: 1: 2 3.1 yellow-brown 6th the same the same Hydrindantine 1: 1: 2 2.4 dark brown the same the same the same 1: 1: 1 3.7 Brown black 7th the same 2-mercaptobenzo- the same 1: 5: 2 5.2 dark brown thiazole 8th. the same 2-M ercaptobenz-
oxazole the same 1: 5: 2 4.7 dark brown 9, the same 2,2'-dithiobis the same 1: 5: 2 5.4 Brown (Benzothiazole) 10. the same 2-benzoxazole thiol the same 1: 5: 2 5.7 dark brown 11th the same 2-benzothiazolol the same 1: 5: 2 4.6 dark brown 12th the same 2 moipholin the same 1: 5: 2 6.5 dark brown thiobenzothiazole 13th the same 2,4-dichloro-l-
NflDhthol the same 1: 1: 2 5.7 Brown black 14th the same X ^ ^ Ai L ' Λ-Λ% 1 It rl
2-chloroacetamide the same 1: 2: 2 7.2 purple black

continuation Piperazine condensate Additive 28 08 310 Relation 10 weight I. g / m ² ι o-phthalic acid p-toluic acid 8: 1: 2 5.0 1 9 15th dicarboxaldehyde Polyketone Color ψ- the same the same 4: 1: 2 2.4 the same the same Ninhydrin 2: 1: 2 4.4 Brown the same the same 1: 1: 2 5.7 m-phthalic acid o-toluic acid the same 2: 1: 1 5.2 Brown 16. dicarboxaldehyde the same Brown 9-anthraldehyde p-toluic acid the same 8: 1: 2 2.4 Brown 17th the same the same Hydrindantine 2: 1: 4 2.9 Brown black the same the same 2: 1: 2 1.8 the same the same Ninhydrin 1: 1: 2 0.8 brown | o-vanillin the same the same 1: 1: 2 3.6 brown 1 18th the same the same the same 2: 1: 2 4.2 brown-black A the same the same the same 4: 1: 2 4.1 dark brown f the same the same the same 8: 1: 2 4.1 brown-black '^r; m-nitrobenzaldehyde m-toluic acid the same 1: 1: 2 4.1 dark brown ^ ₁ 19th the same the same the same 2: 1: 2 4.2 yellow-brown ^ the same the same the same 4: 1: 2 3.7 yellow-brown the same the same the same 8: 1: 2 2.6 dark brown \ \ 2-naphthaldehyde p-toluic acid the same 8: 1: 2 4.1 dark brown "
: » 20th the same the same the same 4: 1: 2 2.0 brown f; the same the same the same 2: 1: 2 3.1 Brown ';)
■ yes the same the same the same 1: 1: 2 2.6 yellow-brown J 1-naphthaldehyde the same the same 8: 1: 2 4.1 dark brown 1 21. the same the same the same 2: 1: 2 4.2 brown black i the same the same the same 1: 1: 2 4.6 brown-black g o-nitrobenzaldehyde the same the same 1: 1: 2 2.9 dark brown | 22nd the same the same the same 2: 1: 2 3.6 brown-black | the same the same the same 4: 1: 2 3.3 black | the same the same the same 8: 1: 2 3.4 black | 1,3,5-trimethoxy the same the same 1: 1: 2 3.3 black 1 23 benzaldehyde the same black S. the same the same the same 2: 1: 2 2.9 black § the same the same the same 4: 1: 2 2.9 purple-black § the same the same 8: 1: 2 2.6 I. 2,4-dinitrobenz
aldehyde the same the same 1: 1: 2 2.9 purple black | 24 the same the same the same 2: 1: 2 3.3 purple black i the same the same the same 4: 1: 2 3.1 dark brown | the same the same the same 8: 1: 2 2.8 black | p-piperazine desgL the same 1: 1: 2 5.2 black | 25th acetophenone the same dark brown 1 the same the same the same 1: 1: 2 4.9 brown 1 26th the same black I. 1 Hydrindantine brown-black I

Claims (5)

Patent claims: 1. Thermal copying material with a heat-sensitive recording layer applied to a support based on a synthetic resin binder containing a color-producing active ingredient pair, characterized in that it is used as an active ingredient pair contains 1) an N-substituted condensation product of a heterocyclic diimino compound and an aromatic aldehyde, the heterocyclic diimino compound from the piperazine, Homopiperazine, 2-alkylpiperazine and 2,5-dialkylpiperazine comprehensive group is selected, and 2) a ring-shaped polyketo compound consisting of ninhydrin, isatin, 5-bromoisatin, 5,7-dichloroisatin, Alloxan, Alloxazin and Hydrindantin comprehensive group is selected. 2. thermal copying material according to claim 1, characterized in that the active substance of type 1) is an aldehyde condensation product of 2-methylpiperazine. 3. thermal copying material according to claim 1, characterized in that the active substance of type 1) is an aldehyde condensation product of 2,5-dimethylpiperazine. 4. thermal copying material according to claim 1 to 3, characterized in that the recording layer additionally substituted ureas, thioureas, gallic acid, o-toluic acid as a stabilizer, m-toluic acid, p-toluic acid, 2-mercaptobenzothiazole and / or 2,2'-dithiobis (benzthiazole) contains. 5. thermal copying material according to claim 1 to 4, characterized in that the recording layer additionally contains an activator.