JP3183948B2 - Thermal recording material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material capable of forming a stable image with respect to oils, plasticizers and the like.

[0002]

2. Description of the Related Art In general, a thermosensitive recording material mainly comprises a color developing system comprising a colorless or pale-color coloring dye as a coloring agent on a support such as paper, synthetic paper, plastic film and the like, and a developing agent which causes the coloring to occur when heated. A thermosensitive coloring layer as a component is provided, and a colored image can be obtained by heating with a hot pen, a thermal head, a laser beam, a strobe lamp or the like. Compared to other recording materials, this recording material can be recorded in a short time with a relatively simple device without performing complicated processing such as development and fixing, has low noise generation and environmental pollution, and has a low cost. It is used for copying books, documents, etc. due to its low cost and other advantages, as well as electronic calculators, facsimile machines, ticket vending machines,
It is useful as various recording materials such as labels and recorders.

As a color-forming dye used for a heat-sensitive recording material, for example, a colorless or light-colored leuco dye having a lactone, lactam or spiropyran ring is used, and as a developer, an organic acid, a phenolic substance or the like is conventionally used. ing. Recording materials using this color former and developer are widely used because of their high image density and high whiteness of the background.

However, such leuco dye-based color images are hardly stable, and are easily erased by touching oils and fats such as fingerprints, machine oil and plasticizers contained in wraps. Has the disadvantage that

In order to improve the stability of such leuco dye-based color images, for example, JP-A-58-49294 uses 3'-hydroxysalicylanilide as a developing agent. JP 60-232992 proposes a method using 3,4-dihydroxybenzoic acid ester as a color developer. Also, Japanese Patent Application Laid-Open
JP-A-135567 proposes a method using a dimerized fluoran compound as a leuco dye. JP-A-59-165678 proposes a method in which a sulfonic acid amide compound is contained in a thermosensitive coloring layer as an image stabilizer. However, it is difficult to say that all of the methods have sufficient image stability and are not practical at present.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a heat-sensitive recording material which is excellent in stability of a color image, especially stability against oils and fats such as a plasticizer.

[0007]

According to the present invention, there is provided a heat-sensitive recording material utilizing a color-forming reaction between a leuco dye contained in a heat-sensitive recording layer and a developer which causes the leuco dye to develop color upon contact. As the leuco dye, the following general formula (I):
There is provided a heat-sensitive recording material characterized by using a fluoran compound represented by (II) or (III) .

[0008]

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[0009]

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[0010]

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(1) 3- (N, N-diethylamino)-
6-methyl-7-anilino-3 ′, 4 ′, 5 ′, 6′-
Tetrachlorofluoran (2) 3- (N, N-diethylamino) -6-methyl-
7-anilino-3 ′, 6′-dichlorofluoran (3) 3- (N-ethyl-N-isopropylamino)-
6-methyl-7-anilino-3 ', 4', 5 ', 6'-tetrabro
Mfluoran

In the present invention, various compounds having an electron accepting property, such as phenolic compounds, thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof, can be used as a color developer. Specific examples include the following, but are not limited thereto. 4,4′-isopropylidenebisphenol, 4,4′-isopropylidenebis-o-methylphenol, 4,4′-sec-butylidenebisphenol, 4,4′-isopropylidenebis (2-tert
-Butylphenol), zinc p-nitrobenzoate, 1,
3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid,
2,2- (3,4-dihydroxydiphenyl) propane, bis (4-hydroxy-3-methylphenyl) sulfide, 4- [β- (p-methoxyphenoxy) ethoxy] salicylic acid, 1,7-bis (4- (Hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, monobenzyl phthalate monocalcium salt,
4,4'-cyclohexylidene diphenol, 4,4 '
-Isopropylidenebis (2-chlorophenol),
2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-butylidenebis (6
-Tert-butyl-2-methylphenol), 1,
1,3-tris (2-methyl-4-hydroxy-5-cyclohexylphenyl) butane, 4,4′-thiobis (6-tert-butyl-2-methylphenol),
4,4′-diphenolsulfone, 4-isopropoxy-4′-hydroxydiphenylsulfone, 4-benzyloxy-4′-hydroxydiphenylsulfone, 4,4 ′
Diphenol sulfoxide, isopropyl P-hydroxybenzoate, benzyl P-hydroxybenzoate, benzyl protocatechulate, stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) propane, N N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, methyl bis- (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, 1,3- Bis (4-hydroxyphenyl) benzene, 1,4-bis (4-hydroxyphenyl) benzene, 2,4′-diphenolsulfone, 2,2′-diallyl-4,4′-hydroxyphenylsulfone, 3,
4-dihydroxy-4'-methyldiphenylsulfone,
Zinc 1-acetyloxy-2-naphthoate, zinc 2-acetyloxy-3-naphthoate, 2-acetyloxy-
Zinc 1-naphthoate, α, α-bis (4-hydroxyphenyl) α-methyltoluene, antipyrine complex of zinc thiocyanate, tetrabromobisphenol A, tetrabromobisphenol S, 4,4′-thiobis (2-methylphenol ), 4,4′-thiobis (2-chlorophenol) and the like.

In order to produce the heat-sensitive recording material of the present invention, a leuco dye, a developer and other auxiliaries may be supported on a support. In this case, as the binder, various conventional binders can be used in appropriate amounts, and specific examples thereof include the following. Polyvinyl alcohol, starch and derivatives thereof, methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, cellulose derivatives such as ethylcellulose,
Sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer In addition to water-soluble polymers such as coalesced alkali salts, polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate, polyurethane, polyacrylate, polymethacrylate, vinyl chloride / vinyl acetate copolymer, ethylene / acetic acid Emulsions such as vinyl copolymers and latexes such as styrene / butadiene / acrylic copolymers.

In the present invention, various heat-fusible substances can be used as a sensitivity improver, and specific examples thereof include the following, but are not limited thereto. Fatty acids such as stearic acid and behenic acid; fatty acid amides such as stearic acid amide and palmitic acid amide; fatty acid metal salts such as zinc stearate, aluminum stearate, calcium stearate, zinc palmitate and zinc behenate; -Benzylbiphenyl, terphenyl, triphenylmethane, benzyl P-benzyloxybenzoate, β-benzyloxynaphthalene, phenyl β-naphthoate, 1-hydroxy-2
-Phenyl naphthoate, methyl 1-hydroxy-2-naphthoate, diphenyl carbonate, gliacol carbonate, dibenzyl terephthalate, dimethyl terephthalate, 1,4-dimethoxynaphthalene, 1,4-diethoxynaphthalene, 1,4- Dibenzyloxynaphthalene,
1,2-diphenoxyethane, 1,2-bis (3-methylphenoxy) ethane, 1,2-bis (4-methylphenoxy) ethane, 1,4-diphenoxybutane, 1,4
-Diphenoxy-2-butene, 1,2-bis (4-methoxyphenylthio) ethane, dibenzoylmethane, 1,
4-diphenylthiobutane, 1,4-diphenylthio-
2-butene, 1,3-bis (2-vinyloxyethoxy) benzene, 1,4-bis (2-vinyloxyethoxy) benzene, P- (2-vinyloxyethoxy) biphenyl, P-aryloxybiphenyl, P -Propargyloxybiphenyl, dibenzoyloxymethane, dibenzoyloxypropane, dibenzyldisulfide,
1,1-diphenylethanol, 1,1-diphenylpropanol, P-benzyloxybenzyl alcohol,
1,3-phenoxy-2-propanol, N-octadecylcarbamoyl-P-methoxycarbonylbenzene,
N-octadecylcarbamoylbenzene, 1,2-bis (4-methoxyphenoxy) propane, 1,5-bis (4-methoxyphenoxy) -3-oxapentane, dibenzyl oxalate, bis (4-methylbenzyl) oxalate , Bis (4-chlorobenzyl) oxalate and the like.

When a heat-sensitive recording material is obtained according to the present invention, if necessary, additives commonly used in this type of heat-sensitive recording material, such as fillers and surfactants, are used together with a leuco dye and a color developer. I can do it. In this case, as a filler, for example, calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate,
Clay, kaolin, talc, surface-treated inorganic fine powders such as calcium and silica, as well as organic fine powders such as urea-formalin resin, styrene-methacrylic acid copolymer, polystyrene resin, and vinylidene chloride resin. Can be mentioned. The layer structure may be a single layer or a multi-layer, and an over layer, an under layer, and a back layer can be provided as needed.

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

Example 1 Each of the following mixtures was ground in a magnetic ball mill for 2 days to prepare [Solution A], [Solution B] and [Solution C]. [Solution A] 3- (N, N-diethylamino) -6-methyl-7-anilino-3 ′, 4 ′, 5 ′, 6′-tetrachlorofluorane 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 Part [Solution B] 4.4'-isopropylidenediphenol 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 parts [Solution C] 20 parts of calcium carbonate 5% aqueous solution of methylcellulose 20 parts Water 60 parts Next [Solution A ], 30 parts of [Solution B], 30 parts of [Solution C], and 10 parts of a 20% aqueous alkali solution of isobutylene / maleic anhydride copolymer to obtain a thermosensitive recording layer forming solution. / M ² of high-quality paper after application and drying so that the amount of the dye adhering agent after drying is 0.5 g / m ² to form a heat-sensitive recording layer. Karen layer surface Have created a heat-sensitive recording material was over over.

Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the following [Solution D] was used in place of [Solution A] in Example 1. [D solution] 3- (N, N-diethylamino) -6-methyl-7-anilino-3 ', 6'-dichlorofluorane 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 parts

Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Solution E] was used instead of [Solution A] in Example 1. [Solution E] 3- (N-ethyl-N-isopropylamino) -6-methyl-7-anilino-3 ′, 4 ′, 5′6′-tetrabromofluorane 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts 60 parts of water

Comparative Example 1 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Solution F] was used in place of [Solution A] in Example 1. [F solution] 3- (N, N-diethylamino) -6-methyl-7-anilino-fluoran 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 parts

Comparative Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that the following [Solution G] was used in place of [Solution A] in Example 1. [Solution G] 3- (N-ethyl-N-isopropylamino) -6-methyl-7-anilinofluorane 20 parts 10% aqueous solution of polyvinyl alcohol 20 parts Water 60 parts

The heat-sensitive recording material obtained as described above was heated to a temperature of 15 using a thermal gradient tester manufactured by Toyo Seiki Seisaku-sho, Ltd.
Printing was performed under the conditions of 0 ° C., a pressure of 2 kg / cm ² , and one second, and the image density and background density were measured using a Macbeth densitometer RD-914.
(Filter: W-106).

Next, the samples after printing were tested for "oil resistance" and "plasticizer resistance" as follows. Table 1 shows the results. "Oil resistance": The density of the image area was measured after applying cottonseed oil to the printed area and storing it for 16 hours under a drying condition at a temperature of 40 ° C. "Plasticizer resistance": A plasticizer (DOA, dioctyl adipate) was applied to the printed portion, and the temperature was 40 ° C. and the temperature was 16 ° C.
The density of the image area after storage for a time was measured. The density measurement after each of the above tests was also performed using a Macbeth densitometer RD-914.
(Filter: W-106).

[0024]

[Table 1]

From Table 1, it can be seen that the heat-sensitive recording materials of the examples have improved image area stability and are extremely excellent in oil resistance and plasticizer resistance.

[0026]

As described above, the heat-sensitive recording material of the present invention using the fluoran compound represented by the general formula (I), (II) or (III) as a leuco dye contained in the heat-sensitive recording layer has an oil resistance and a resistance to oil. It has extremely high plasticizer properties and is highly practical.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-64592 (JP, A) JP-A-59-207283 (JP, A) JP-A-63-256487 (JP, A) JP-A-1- 174486 (JP, A) JP-A-54-109454 (JP, A) JP-A-59-143682 (JP, A) JP-A-59-199758 (JP, A) (58) Fields investigated (Int. ⁷ , DB name) B41M 5/30 CA (STN) REGISTRY (STN)

Claims (3)

(57) [Claims] 1. A thermosensitive recording material comprising a support having thereon a thermosensitive recording layer mainly composed of a leuco dye and a developer capable of developing the leuco dye upon contact, wherein the leuco dye is
3- (N, N-diethyl ) represented by the following general formula (I)
Amino) -6-methyl-7-anilino-3 ', 4', 5 ', 6'-
A heat-sensitive recording material characterized by using tetrachlorofluorane . Embedded image 2. A leuco dye and the leuco dye on a support.
Thermosensitive recording layer mainly composed of a color developer that develops color upon contact
In the thermosensitive recording material provided with, as the leuco dye,
3- (N, N-diethyl) represented by the following general formula (II)
Amino) -6-methyl-7-anilino-3 ′, 6′-dichlo
A heat-sensitive recording material using rofluorane. Embedded image 3. A leuco dye and the leuco dye on a support.
Thermosensitive recording layer mainly composed of a color developer that develops color upon contact
In the thermosensitive recording material provided with, as the leuco dye,
3- (N-ethyl-N represented by the following general formula (III)
- isopropylidenediphenol arylamino) -6-methyl-7-anilino -
Use of 3 ', 4', 5 ', 6'-tetrabromofluoran
Characteristic thermal recording material. Embedded image