JPH04224996A - Electron accepting coloring material and recording method - Google Patents

Abstract

PURPOSE:To obtain a thermal recording material and recording method easy to manufacture wherein heat sensitivity is high, fading and discoloring hardly occur, and coloring does not occur even if the material contacts with organic solvent by developing a new type electron accepting coloring material. CONSTITUTION:An electron accepting coloring material consisting of an organic phosphoric acid compound to be expressed by a general formula R-PO(OH)2 where the R represents hydrocarbon radical which may have a substitutional radical, and a recording method to make the coloring material react with a coupler.

Description

[Detailed description of the invention]

0001

TECHNICAL FIELD The present invention relates to an electron-accepting color developer and a recording method.

0002

[Prior Art and its Problems] Heat-sensitive recording materials are used for the output of electronic computers, facsimile machines, automatic ticket vending machines, printers of scientific measuring instruments, or CRTs for medical measurement because the recording devices are compact, inexpensive, and easy to use. It is widely used in printers, etc. In such heat-sensitive recording materials, an electron-accepting color developer is used together with an electron-donating color former. Conventionally used color developers include, for example, salicylic acid, gallic acid, metal salts of these acids, phenolic compounds, and solid acids such as activated clay, silica gel, and bentonite. Among them, phenolic compounds such as 4,4'-isopropylidenediphenol [bisphenol A], 4,4'-
Isopropylidene bis(2-chlorophenol), 4,
4'-isopropylidene bis(2-methylphenol)
, 4,4'-isopropylidene bis(2,1-tert
-butylphenol), 4,4'-sec butylidene diphenol), 4,4'-cyclohexylidene diphenol, 4-tert-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, naphthol, β-naphthol, methyl- 4-hydroxybenzoate, 4-hydroxy-acetophenone, salicylic acid anilide, novolac type phenolic resin, 4,4'-dihydroxydiphenylsulfone, 2,4-dihydroxydiphenylsulfone, 3,3'-dihydroxydiphenylsulfone, 3,3'- Diamino-4,4-dihydroxy-diphenylsulfone and the like are in practical use because of their excellent color tone, image density, storage stability, heat resistance, and the like. However, since the combination of these phenolic compounds and leuco compounds has a poor color development rate with respect to heat, that is, heat sensitivity, it is actually necessary to use heat-fusible substances called sensitizers, such as stearic acid amide, oleic acid amide, behenic acid amide, coconut amide, etc. The reality is that fatty acid amides such as fatty acid amide, waxes such as zinc stearate, polyethylene wax, carnauba wax, and paraffin wax are used in combination, leading to increased costs. Furthermore, since color develops upon contact with organic solvents such as acetone and alcohol, when forming a recording layer on a support to produce a recording material, there is a manufacturing restriction in that only water can be used as a solvent.

0003

SUMMARY OF THE INVENTION The object of the present invention is to eliminate the above-mentioned drawbacks and provide an image that is highly sensitive to heat and does not easily fade or change color, and that does not easily develop color even when pressure is applied or when it comes into contact with organic solvents. The object of the present invention is to provide a color developer and a recording method that provide a heat-sensitive recording material that is easy to manufacture and has practical use.

0004

[Means for Solving the Problems] As a result of extensive research in order to solve the above problems, the present inventors have discovered that the above problems can be solved by using an organic phosphoric acid compound as a color developer. , we have completed the present invention.

That is, according to the present invention, an electron-accepting color developer is provided from an organic phosphoric acid compound represented by the following general formula. (In the formula, R is a hydrocarbon group that may have a substituent)

According to the present invention, there is also provided a recording method comprising the step of reacting an electron-accepting color developer made of an organic phosphoric acid compound represented by the above general formula with an electron-donating color former.

The hydrocarbon group which may have a substituent in the general formula (1) includes, for example, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, and an aralkyl group. More specifically, C1-C30 linear alkyl group or branched alkyl group, C1-C30 linear alkenyl group or branched alkenyl group, substituted or unsubstituted cyclohexyl group, unsubstituted or substituted phenyl group , naphthyl group, benzyl group and the like. Substituents include C1 to C30 linear or branched alkyl groups, alkenyl groups, alkoxy groups, as well as hydroxyalkyl groups, hydroxyl groups, amino groups, cyano groups, carboxyl groups,
Examples include halogen.

Specific examples of the color developer of the present invention are shown below. Ethylphosphonic acid, butylphosphonic acid, tert-butylphosphonic acid, hexylphosphonic acid, cyclohexylphosphonic acid, octylphosphonic acid, decylphosphonic acid, dodecylphosphonic acid, pentadecylphosphonic acid, hexadecylphosphonic acid, octadecylphosphonic acid, docosyl Phosphonic acid, tetracosylphosphonic acid, isohexylphosphonic acid, 1-hexenylphosphonic acid, iso-1-pentynylphosphonic acid, phenylphosphonic acid, 1-naphthylphosphonic acid, 4-tertbutylphenylphosphonic acid, 2-
Chlorophenylphosphonic acid, 4-(β-hydroxyethyl)phenylphosphonic acid, 4-butoxyphenylphosphonic acid, 4-dodecylphenylphosphonic acid, etc.

On the other hand, as the electron-donating color forming agent (leuco dye) used together with the color developer of the present invention, all those known in the technical fields such as pressure-sensitive recording and heat-sensitive recording can be used. A specific example is shown below. Crystal violet lactone, 3,3-bis(P-dimethylaminophenyl) phthalide, 3,3-bis(P-dimethylaminophenyl)-6-diethylaminophthalide, 3,3
-bis(P-dibutylaminophenyl)phthalide, 3-
Dimethylamino-5,7-dimethylfluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-5,7-benzfluorane, 3-pyrrolidino-6
-Methyl-7-anilinofluorane, 3-N-methyl N
-amylamino-6-methyl-7-anilinofluorane, 3-N-methyl-N-cyclohexylaminofluorane, 3-N,N-diethylamino-6-methyl-7-anilinofluorane, 3-(N , N-diethylamino)-
5-Methyl-7-(N,N-dibenzylamino)fluoran, benzoylleucomethylene blue, 3-(2'-
Hydroxy-4'-diethylaminophenyl)-3-(
2'-methoxy-5'-methylphenyl)phthalide, 3
-morpholino-7-(0-trifluoromethyl)anilinofluorane, 3-pyrrolidino-7-(0-trifluoromethyl)anilinofluorane, 3-(N-n-butyl-N
-n-propyl)amino-7-(m-acetyl)anilinofluorane, 3-(N,N-di-n-butyl)amino-7-(P-acetyl)anilinofluorane, 3-octylamino -7-(2,4-dinitro)anilinofluorane, 3-(N-benzyl-N-cyclohexyl)amino-6-methyl-7-anilinofluorane, and the like.

To prepare a heat-sensitive recording material using the color developer of the present invention, a recording layer containing the color developer and color forming agent of the present invention is provided on a support such as paper, synthetic paper, plastic sheet or film. This recording layer contains, for example, acrylic resin, terpene resin, vinyl acetate resin, styrene resin, polyester resin, ethylene-vinyl acetate copolymer, polyvinyl alcohol, cellulose, starch, etc., in order to bind it onto the support. It is desirable to contain casein, gelatin, wax and other known organic solvents or water-soluble binders.

[0011]Although it is preferable from the viewpoint of manufacturing that the color developer of the present invention be included in the same layer as the color former, they can also be included in separate layers. In addition, when the color forming agent and the color developer are mixed together with a binder and the mixed solution is coated on a support to form a recording layer, the temperature range that does not cause color development is required. Mix and dry. The heat-sensitive recording material produced in this manner always provides clear images and has excellent weather resistance and long-term storage stability.

0012

EXAMPLES Next, the present invention will be explained in more detail with reference to examples. Note that all parts and percentages shown below are based on weight.

Example 1 The following composition was sufficiently stirred to prepare a thermosensitive coloring layer forming liquid. 5% solution of polyvinyl butyral (trade name Esleciku BX-1: manufactured by Sekisui Chemical Co., Ltd.) (solvent: tetrahydrofuran/MEK = 1/1
) 100 parts 3-(N-methylN-cyclohexylamino)-6-methyl-7-anilinofluorand
2 parts Decylphosphonic acid [C12H
25PO(OH)2, m. p. 98.8° C.] 6 parts of this solution was applied onto a 100 μm thick polyester film using a wire bar to a film thickness of 1.5 μm and dried to prepare a heat-sensitive recording material. The heat-sensitive recording material obtained as described above was printed using a thermal gradient tester manufactured by Toyo Seiki Seisakusho at a temperature of 130°C, a pressure of 2 kg/cm2, and 1 second, and the image density and background density were measured as Macbeth density. Total RD
-914 (filter: V-106). Next, the printed sample was tested for oil resistance and alcohol resistance. In these tests, cottonseed oil or ethyl alcohol was applied to a sample, and the concentration in the image area and background area was measured after storage for 24 hours. Incidentally, the concentration measurement after each of these preservability tests was also performed using a Macbeth densitometer RD-914 (filter: V-106). The above results are shown in Table 1.

Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 using the following composition. Ethyl cellulose (100 cps, manufactured by Kanto Kagaku Co., Ltd.) (Solvent: Tetrahydrofuran/Toluene = 2/
1) 100 copies 3-(N,
N-di-n-butyl)amino-6-methyl-7
−Anilinofluorane
2 parts Hexadecylphosphonic acid [C16H33PO(OH)2, m. p
．． 960° C.] Six copies of the obtained recording material were subjected to the same test as in Example 1. The results are shown in Table 1.

Example 3 The following mixtures were each ground in a magnetic ball mill for two days to prepare liquids A, B and C. [Liquid A] 3-(N-methyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane
20 copies
10% aqueous solution of polyvinyl alcohol
20 copies
water

60 parts [Liquid B] Tetradecylphosphonic acid [C14H29PO(
OH) 2, 20 copies

m. p. 97.2°C] 10% aqueous solution of polyvinyl alcohol
20 parts water

60 copies
[Liquid C] Calcium carbonate

20 parts 5% aqueous solution of methylcellulose
20 parts water

Part 60 [
10 parts of [Liquid A], 30 parts of [Liquid B], 30 parts of [Liquid C], and 10 parts of a 20% alkaline aqueous solution of isobutylene/maleic anhydride copolymer are mixed to prepare a thermosensitive coloring layer forming liquid, and this is determined by the basis weight. 0 amount of dye adhesion after drying on 50g/m2 high quality paper
．． A heat-sensitive coloring layer was provided by coating and drying at a density of 5 g/m2, and then the layer surface was calendered to have a surface smoothness of 500 to 600 seconds to prepare a heat-sensitive recording material. The heat-sensitive recording material obtained as described above was subjected to the same tests as in Example 1. The results are shown in Table 1.

Example 4 In Example 3, the leuco dye in solution A was replaced with 3-(N-methyl-N-isobutylamino)-6-methyl-7-anilinofluorane, and the developer in solution B was replaced with 4-(N-methyl-N-isobutylamino)-6-methyl-7-anilinofluorane. A heat-sensitive recording material was obtained in the same manner as in Example 3 except that tert-butylphenylphosphonic acid was used instead. The same tests as in Example 1 were conducted on this heat-sensitive recording material. The results are shown in Table 1.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 3 except that the color developer of liquid B was replaced with conventional 4,4'-isopropylidenediphenol (bisphenol A). . The same tests as in Example 1 were conducted on this heat-sensitive recording material. The results are shown in Table 1.

Comparative Example 2 A heat-sensitive recording material was obtained in the same manner as in Example 3, except that the color developer of liquid B was replaced with the conventional benzyl P-hydroxybenzoic acid ester. The same tests as in Example 1 were conducted on this heat-sensitive recording material. The results are shown in Table 1.

[0019]

[Table 1]

Example 5 The same procedure as in Example 3 was carried out except that the color developer of liquid B in Example 3 was replaced with 10 parts of 4,4'-isopropylidenediphenol (bisphenol A) and 10 parts of dodecylphosphonic acid. A thermosensitive recording material was obtained. The same tests as in Example 1 were conducted on this heat-sensitive material. The results are shown in Table 2.

[0021]

[Table 2]

Effects of the Invention From the results in Tables 1 and 2, it can be seen that the heat-sensitive recording materials using the color developer of the present invention have high image density and are highly reliable. Further, the color developer of the present invention can be used in combination with a conventional color developer, such as the above-mentioned phenolic compound, if necessary. When used in combination, the heat sensitivity is higher than when a phenolic compound is used alone, and a high concentration can be obtained.

Claims (2)

[Claims] 1. An electron-accepting color developer comprising an organic phosphoric acid compound represented by the general formula (wherein R is a hydrocarbon group which may have a substituent). 2. A recording method comprising the step of subjecting an electron-accepting color developer comprising the organic phosphoric acid compound of claim 1 to a heat reaction with an electron-donating color former.