JPS595438B2 - heat sensitive recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention comprises a layer of a fusible film-forming binder containing at least one color former and an electron acceptor as a color developer, either separately or in admixture. Regarding the heat-sensitive recording material having the color forming agent, the color forming agent has the general formula: 'N, ゛・c=0' is a benzene ring group substituted with R2
and R- are each hydrogen, a lower alkyl group or an aryl group, preferably a benzene-based group, R3 and R'l are hydrogen, a lower alkyl group or a lower alkoxyl group, and R1 and R are each 6 carbon atoms. ~18
It is characterized by being a compound represented by an alkyl group having 3 to 18 carbon atoms or an alkenyl group having 3 to 18 carbon atoms.

Ring A is a benzene ring that is unsubstituted or substituted with a halogen or nitro group. Of particular importance are rings A, such as unsubstituted benzene rings or halogenated, especially chlorinated benzene rings, such as the tetrachlorobenzene ring. The substituents R1 and R( are each an unsubstituted alkyl group of 6 to 18 carbon atoms or an unsubstituted alkenyl group of 3 to 18 carbon atoms.

Such substituents R1 and RS include hexyl, heptyl, octyl, nonyl, decyl, dodecyl, and stearyl groups. When R1 or R} is an alkyl group, it preferably contains 6 to 18 carbon atoms.

R and R2 are especially hydrogen or an alkyl group having 1 to 4 carbon atoms, such as butyl, probyl, ethyl or especially methyl. Furthermore, R2 and R: are aryl groups, such as tolyl, chlorophenyl, methoxyphenyl or especially phenyl. 5- or 5- of an indole group when the group R3 or R3 is not hydrogen
' is preferably in one position. This represents 1 to 1 carbon atom
Preferred are alkyl or alkoxyl groups having 4 atoms, such as methyl, methoxy, ethoxy, probyl or butyl. Of great importance are color formers in which R3 and R'3 are hydrogen.

Color formers of the formula are particularly well suited.

Particularly advantageous color formers are compounds of the general formula.

The color formers used according to the invention are known, for example from Swiss Patent No. 484,251.

This color former can be made by a two-step process or a one-step process. In a two-step process, 1 mole of indole is reacted with 1 mole of phthalic anhydride in the first step in a solvent such as benzene in the presence of a Friedel-Crafts catalyst such as AlCl3.

The intermediate product thus obtained is isolated, purified by recrystallization or chromatographic methods and then reacted with a further 1 mole of indole in the presence of a condensing agent, such as, for example, acetic anhydride. In a one-stage process according to Swiss Patent No. 484,251, 2 moles of indole are reacted with about 1 mole of anhydride, preferably from 1.0 to 1.2 moles, in the presence of a condensing agent.

Examples of the anhydride component represented by the general formula (4) include phthalic anhydride substituted with a nitro group or a halogen, particularly chlorine, or phthalic anhydride itself.

Accumulation lump "6 +) -? - 4 moves I reflex N" ↓l γl
11 ko'1-[■3,4-dichlor-3,5
-dichlor-3,6-dichlor-, 4,5-dichlor-
, trichlor-1, tetrachlor-1, 3-bromo-, 4-
Mention may be made of bromo-, tri-bromo-, tetra-bromo-phthalic anhydride, tri- and tetra-fluorophthalic anhydride. Suitable indole components include, for example, 1-allyl-2-methylindole, 1-hexyl-2-methylindole, 1-heptyl-2-methylindole,
1-octyl-2-methylindole, 1-nonyl-2
-methylindole, 1-decyl-2-methylindole, 1-dodecyl-2-methylindole, and 1-stearyl-2-methylindole.

These pthalads are used according to the invention as color formers in heat-sensitive recording materials.

In particular, products in which the anhydride component is substituted, especially halogenated 3,3-bis(indolyl)-putalade,
It is valuable because its absorption part is shifted towards longer wavelengths compared to the unsubstituted product. Also of particular interest are color formers in which the radicals R1 and R} each contain at least 6 carbon atoms.

The substituent on the nitrogen atom of the indole ring has 6 to 18 carbon atoms.
3,3-bis-(indolyl)-putalade, which has sufficient solubility, is particularly suitable for use as a coloring agent in heat-sensitive recording materials. It was found that the concentration was high.

In the heat-sensitive recording material of the invention, what is important is a recording material or recording paper that is suitable for mere recording purposes and for use as copying paper or reproduction paper by thermal recording methods.

This recording is carried out mechanically or manually in information recording devices, such as facsimile or telegraph recording devices, printing telegraphs or printing telegraph measuring machines, electronic computers, various measuring instruments and copying machines, or by means of a hot pen. In order to make a copy of an ordinary record (for example a print) on a so-called transfer paper, it is sufficient to heat it, for example with infrared radiation, so that the record is transferred to the receiver paper exactly as it was in the original.

The recording material according to the invention therefore contains at least as its own recording components a colorless lactone as a coloring agent, an electron acceptor capable of converting the coloring agent into a dye, and a binder.

In this recording material, the color former and the color developer (electron acceptor) are each dissolved or dispersed separately in a fusible film-forming binder and applied onto separate papers or sheets. Alternatively, a color former layer and a color developer layer are coated in layers on the same paper or sheet.

In other embodiments, the color former and color developer are dispersed in the same layer. When the binder is softened in situ by heat, the color former and the color developer come into contact at the heated location, and the dye is developed at that location to form an image record. Color developers include Lewis acids such as so-called attapulgas or Silton bands, acidic phenolic compounds or resins, or organic acids.

To develop color, it is preferred that the selected electron acceptor is solid at room temperature and melts or becomes fluid at about 50° C. or higher. Examples of phenolic compounds include 4-3
Butylphenol, 4-phenylphenol, 4-hydroxydiphenyl oxide, α-naphthol, 4-hydroxybenzoic acid methyl ester, β-naphthol, 4
-Hydroxyacetophenol, 4-tert-octylbrennocatechin, 2, goo-dihydroxydiphenyl, 2
, i-methylene-bis-(4-chlorophenol), 1
, 1'-isopropylidene diphenol (bisphenol A), 4,4'-isopropylidene-bis-(2-chlorophenol), 4,4'-isopropylidene-bis-(2,5-dipromophenol) , 4,4/-isopropylidene-bis-(2,6-dichlorophenono(), 4,4'-isopropylidene-bis-(2-methylpheno(), 4,4'-secondary iso()) butylidene diphenol, 4,1-cyclohexylidene diphenol,
4,4'-(1-methyl-n-hexylidene)-diphenol, 2,i-thio-bis-(4,6-dichlorophenono(he)), hydroquinone, pyrogallol, phloroglucin and phloroglucin carboxylic acid Suitable organic acids include, for example, p-, m- and 0-hydroxybenzoic acid, boric acid, tartaric acid, oxalic acid, macinic acid, citraconic acid, succinic acid, gallic acid, 1-hydroxy-2-naphthenic acid. or 2-hydroxy-p-toluic acid.

Since the color former and color developer are water-insoluble, it is preferred to use water-soluble products as the fusible film-forming binder. The binder is capable of dispersing and fixing the color former and the color developer at room temperature, so that both are contained in unbound form in the material. The binder softens or melts when heated, allowing the color former to contact the color developer and color development to occur. Binders that are water-soluble or at least swell in water include, for example, polyvinyl alcohol, polyacrylic acid, styrene-maleic anhydride copolymers, hydroxyethyl cellulose, polyacrylamide, carboxymethyl cellulose, methoxy cellulose, methyl cellulose, polyvinyl biloryl. Examples include don, gelatin, casein, zinc caseinate, and pectin.

When the color former and the color developer are applied in two different layers, a binder which is water-insoluble or soluble in non-polar or weakly polar organic solvents can be added. Examples include natural rubber, synthetic rubber, chlorinated rubber, alkyd resins, polystyrene, styrene-butadiene copolymers, polymethyl methacrylate, ethylcellulose, nitrocellulose or polyvinylcarbazole. However, according to the invention it is preferred to use a water-soluble binder together with the color former and the color developer in one layer. The laminate of recording material may further contain additives.

For example, talc, titanium dioxide, zinc oxide or calcium carbonate can be added to improve the whiteness and printability of the recording paper and to prevent the thermal pen from sticking. In order to carry out the development in a narrow temperature range, the desired fusible substance such as urea, acetanilide, phthalic acid, or the like, at which point of its inherent melting, the color Tj and the color developer are transferred to the molten state, is added. can be used. Shizou Prescription
25.6 parts of 1-hexyl-2-methyl-indole and 32.6 parts of phthalic anhydride are stirred together at 100 DEG C. for 2 hours.

The mixture was cooled to 50°C and at this temperature 94% of acetic anhydride was added.
Add parts by volume and stir the whole thing for 6 hours. After this, 300 parts of water are added and the mixture is further stirred for at least 1 hour. The suspension is neutralized with ammonia and the product is filtered. The 3,3-his-(1'-hexyl-2'-methylindole-35-ino(he)-putalade thus obtained) is washed with water and dried. Compound 101 (melting point 140-150°C) is obtained. The yield is 97% of theory. The compound exhibits a maximum absorption at 533 nm in 95#) acetic acid. The compounds shown in the following table, represented by , can be obtained in a similar manner.

B. a) 1-decyl-2-methyl-indole27.
1 part of tetrachlorophthalic anhydride and 30 parts by volume of acetic anhydride are stirred together at 100 DEG C. for 6 hours.

This reaction mixture was prepared by formula A. The product is treated as described above, but the product is washed with methanol before drying. Melting point 15
3,3-bis-(1'-decyl-Z
-methyl-indole-3'-yl)-4,5,
6,7-Tetrachlorptalade (compound No. 206) is obtained in a yield of 91% of theory.

Similarly, tetrachlorphthalide represented by the general formula (in this formula, R1 and R have the meanings shown in Table 2 below) is obtained.

C. Using mononitrophthalic anhydride instead of tetrachlorophthalic anhydride, formulation B. According to the method described in , a dye represented by the following general formula is obtained.

Example 1 a) Color former (103) 79, 10 (!) Aqueous preparation of viscosity 23-28 centipoise by grinding 3009 aqueous polyvinyl alcohol solution and 130 ml of water together for 1 hour make.

The color former particles have a diameter of about 1 to 3 microns. b) 4,4/-
Isopropyritene diphenol 709 and 1001)
The aqueous polyvinyl alcohol solution 3009 is ground together with 130 ml of water for 1 hour.

The particle size after grinding is 1-3μ. c) Color former dispersion 69
and Phenol Dispersion 1349 were mixed, and the application amount was 0.
．． Dye the cloth on paper so that it becomes 3 to 0.459/cm.

The dried paper is coated with 3% color former, developer 670/) and polyvinyl alcohol 3001). Place the laminated paper layer side down on the untreated paper surface.

When a mark is made on the surface of the two-sheet system with a thermal pen, the mark is faithfully transferred to the second, underlying paper.

Similar results can be obtained by substituting color formers 103 with other color formers of formulations A-C. Example 2 The following Parts A and B are ground separately in a ball mill, dispersed, and mixed.

Solution A: Color former (103) 195#) Hydroxyethyl cellulose aqueous solution 51 water
59B solution: 4,4'-(1-methylhexylitene)-diphenol 49 Phenono I diphenol obtained by condensation of 1 mole of 4,4'-isopropyritene diphenol and 2 moles of formalde7de 1g501)
Hydroxyethylcellulose aqueous solution 25g water
229 The mixture thus obtained is applied as a paint onto plain paper having a weight of 509/CTrL, so that the coated layer after drying is approximately 49/CTn.

Drying is performed at a temperature of 40°C or less. A heat-sensitive recording paper is thus obtained. The basic color of the paint layer is white and is stable even after long-term storage at room temperature. This recording paper takes on a red color when touched with a hot pen or by hot writing. The writing on this paper virtually never fades after being recorded and stored for a long period of time. Example 3 First, two dispersions (liquid A and liquid B) are prepared.

Color former 19 represented by formula (204) to make liquid A
, 50f) Ethyl cellulose aqueous solution 59 and 4.49
is ground in a ball mill for 2 days. P to make liquid B
, p'-(1-methyl-n-hexylidene-diphenol 59, 501) hydroxyethyl cellulose aqueous solution 2
59 and water 229 are similarly ground in a ball mill for 2 hours. The two dispersions are then mixed.

This flowable mixture is applied onto plain paper having a areal weight of 509/CrrL. This laminated paper is dried. Construction amount is 39
/d (dry weight). The heat-sensitive recording paper thus obtained is stable at room temperature.

The basic color of the construction layer is mostly white. The color rapidly develops to red at about 90°C. A clear record can be obtained by touching the thermal pen. Example 4 The following dispersions are made separately.

(4) Color former represented by formula (201) 259 and 1 of hydroxypropyl methylcellulose having a degree of methoxyl substitution of 19 to 24 and a degree of fluoropylene glycol substitution of 4 to 12
(T) solution (20!) solution, 400 cps) together 2
Grind for an hour and filter this mixture.

8 Isopropyritene diphenol 209, oil absorption 82
30 g of colloidal calcined kaolin cd/100 g and hydroxypropyl methylcellulose (1% solution in water) 2009 as dispersion A are ground together for 2 hours and the mixture is filtered.

(A) 12.5 parts by weight and 8250 parts by weight are mixed,
The mixture thus obtained was coated with pure cellulose paper (609/c).
! l) Coated on top to a thickness of 5-10μ and a surface weight of 4.6
Create a layer of ~79/Cd.

The layer thus obtained produces a red mark when brought into contact with a heat-applying type head. The marks thus obtained and the untreated background retain their well-defined morphology when exposed to sunlight and moisture. Example 5 Color former 209 represented by formula (101) and copolymer of styrene and maleic anhydride 109 are mixed and ground for 1 hour until the particle size of the color former becomes 0.5 to 2 microns.

The phenolic synthetic resin 609 and the copolymer of styrene and maleic anhydride 109 are mixed in the form of a solution and ground for 1 hour until the particle size of the phenolic synthetic resin is 2 to 3 microns. Next, mix the two ingredients and place on paper to a thickness of 2 to 5 cm.
Apply to micron (when dry). The heat-sensitive material thus obtained is subjected to pressure at about 10-160°C using a heating element.

A clear red record is obtained. Example 6 A color former 209 represented by formula (106) and a copolymer of styrene and maleic anhydride 109 are mixed and ground for 1 hour until the size of color former particles becomes 0.5 to 2 microns.

A mixture consisting of phenolic synthetic resin 559, copolymer of styrene and maleic anhydride 109, and myristic acid 5f1 is ground for 1 hour until the particle size of the phenolic synthetic resin becomes 1 to 2 microns. The two previously obtained components are then mixed and coated onto a paper substrate to a thickness of 2 to 5 microns (when dry) to produce a heat-sensitive recording material. When pressurized with a heating element at a temperature of 60-110°C, a red color record is obtained. Example 7 A. 4,4/-isoprohyritene diphenol 859,
Water 1159 and 7.5% hydroxyethyl cellulose aqueous solution 2009 are pulverized until the average particle size is 3 microns.

This preparation is then applied to a so-called receiver paper. B. formula(
Color forming agent 709 represented by 301), 7.501) Polyvinyl alcohol aqueous solution 4009 and water 309 are ground together until the average particle size becomes 3 μm.

This preparation is then applied to a so-called transfer paper. Lay the two pieces of paper (4) and Q3) on top of each other with the construction sides facing each other.

Mechanically add records to the paper (B). By infrared irradiation, a copy of the record on paper (B) is obtained in red on paper (4). Comparative Experiment Among the color formers with the following general formula, the color density was determined by the following method for a compound in which R is an n-octyl group (Compound 103 in Table 1) and a compound in which R is an ethyl group (hereinafter referred to as ``compound 103''). compared.

By a method similar to Example 1, compounds 716103,
The compound and the developer 4,4'-isopropylidene diphenol were separately ground and mixed.

In this case, the weight ratio of color former to developer was 1:3. Each color former and developer were mixed and applied onto typewriter paper at a ratio of 2.79/Trl.
The thermal transfer paper thus obtained was white in color. Next, these papers were developed by a thermal recording method using hot needles at 100°C, 110°C, 120°C, and 130°C, respectively. The density of the obtained red color was higher in Compound 103 in which R is an octyl group in the above chemical formula than in the compound in which R is an ethyl group.

Claims (1)

[Scope of Claims] 1. A heat-sensitive film having a layer of a fusible film-forming binder containing at least one color former and an electron acceptor as a color developer, either separately or in a mixture. In the recording material, the above-mentioned color forming agent has the formula ▲ mathematical formula, chemical formula, table, etc.
_2 are each hydrogen, a lower alkyl group or an aryl group, R_3 and R'_3 are each hydrogen, a lower alkyl group or an alkoxyl group, and R_1 and R
'_1 is an unsubstituted alkyl group having 6 to 18 carbon atoms or an unsubstituted alkenyl group having 3 to 18 carbon atoms.