JPS62173288A - Thermal recording material - Google Patents

Abstract

PURPOSE:To enable recorded images to be read by an OCR, a bar code reader employing semiconductor laser or the like, by using specified compounds respectively as a leuco dye and a color reaction agent in a recording material which comprises a leuco dye, as a color former, and a color reaction agent. CONSTITUTION:A compound of formula (I) is used as a leuco dye, and a compound of formula (II) or (III) is used as a color reaction agent, in a thermal recording material which utilizes a color forming reaction of the leuco dye with the color reaction agent capable of developing the color of the dye when being brought into contact with the dye. In the formulas, each of R1-R4 is hydrogen or an alkyl, each of R5 and R6 is hydrogen or phenyl, R7 is an alkyl or phenyl, R8 is -CHO, a halogen, hydrogen atom or the like, A is a benzene ring or naphthalene ring, and R11 is hydrogen atom, a 1-4C alkyl or alkoxyl.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to improvements in recording materials that use leuco dyes as color formers, and in particular to improvements in heat-sensitive recording.

[Prior art]

Recording materials using leuco dyes have been known for a long time.
It is used as pressure-sensitive recording paper, heat-sensitive recording paper, etc., and its usage is increasing year by year. Leuco-based pressure-sensitive recording materials generally utilize a chemical reaction between a colorless leuco dye and a coloring agent that develops color upon contact with the leuco dye to form a colored image. Specifically, a coloring agent sheet coated with a microcapsule solution of leuco dye in an organic solvent and a coloring agent sheet coated with a coloring agent and a binder are placed one on top of the other, and the two sheets are coated from the back side. The pressure capsule is destroyed by the pressure of a pen, etc., and a color reaction occurs.

On the other hand, leuco-based thermosensitive recording materials are placed on a support.

It supports a leuco dye and a coloring agent, and when an image signal is thermally applied using a micro-heating resistor element, a colored image is generated.

Compared to other recording materials such as electrophotography and electrostatic recording materials, pressure-sensitive and heat-sensitive recording papers do not require complicated processes such as development and fixing, and can be produced quickly using relatively simple equipment. It is used in many ways because it allows time records to be obtained. The leuco dyes mainly used in such recording materials include crystal violet lactone, blue dyes represented by leuco crystal violet, and black dyes represented by 7-anilino-substituted fluoran compounds. In recent years, optical character reading devices and label barcode reading devices have been developed, and their usage is increasing. However, these devices use light-emitting diodes or semiconductor lasers as light sources with light wavelengths of 700 mμ.
The above light sources are commonly used. However, the above-mentioned blue dye and black dye have almost no light absorption in the near-infrared region of 700 mμ or more, so it is impossible to read the color with the above-mentioned reading device. Therefore, the light absorption wavelength of one chromophore is 7
At present, there is a strong demand for the development of new leuco dyes with a diameter of 00 mμ or more.

In the past, several proposals have been made regarding leuco dyes that absorb long wavelengths.
No. 38 and Japanese Unexamined Patent Publication No. 57-167979, these dyes have drawbacks of being difficult to synthesize and very high in cost.

〔the purpose〕

The present invention uses a novel leuco dye that absorbs light in the near-infrared region to provide a heat-sensitive recording material that can be read by an optical character reader, a barcode reader using a semiconductor laser, etc. The purpose is to

〔composition〕

According to the present invention, in a recording material that utilizes a color-forming reaction between a leuco dye and a color-forming agent that causes the leuco dye to develop a color upon contact, at least one of the leuco dyes is represented by the following general formula CI>. is a compound, and at least one of the color formers has the following general formula (II) or general formula (m).
Provided is a heat-sensitive recording material characterized in that it is a compound represented by the formula 6 and further contains a transition metal compound (wherein RL rR2 + R3 + R4 is hydrogen or a substituted or unsubstituted alkyl group, or an unsubstituted phenyl group, R7 is a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group) (Rg represents -COOR, -COR, ., -CHO, halogen, or a hydrogen atom; In this case, R9 and Rto represent an optionally substituted aryl group, aralkyl group, alkyl group, or alkoxy group. n is the number of substituents, and n=1 to 3.
is an integer of , and in this case, the types of substituents may be different. ) represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group. (n is the number of substituents and is an integer of 1 to 4; in this case, the types of substituents may be different) The leuco dye represented by the general formula (1) used in the present invention is usually pale yellow. Since the color tone is greenish-blue, sufficient contrast can be obtained even when used alone, but it is also possible to use other leuco dyes in combination to adjust the color tone.

Specific examples of the compounds of the above general formula include those shown below.

Specific examples of the color forming agent represented by the general formula (II) or (Ill) used in the present invention include those shown below, but are not necessarily limited thereto.

Examples of transition metal compounds used in the present invention include vanadium compounds, chromium compounds, manganese compounds, iron compounds, cobalt compounds, nickel compounds, copper compounds, zinc compounds, tin compounds, and aluminum compounds.

In addition, the forms of metal compounds include hydroxides, halides, sulfates, nitrates, phosphates, acetic acid, propionic acid,
Fatty acid salts such as lauric acid, stearic acid, and behenic acid,
Examples include various carboxylates, sulfonates, sulfides, oxides, and coordination compounds such as diethylthiocarbamic acid and acetylacetone, but are not limited to these.

In the present invention, the leuco dye represented by the general formula CI) can be used in combination with other leuco dyes. In this case, the leuco dye used in combination is generally a leuco dye known for this type of leuco recording material. For example, leuco compounds of triphenylmethane-based, fluoran-based, phenothiazine-based, auramine-based, spiropyran-based, and indolinophthalide-based dyes are preferably used.

Specific examples of such leuco dyes include those shown below.

3.3-His(P-dimethylaminophenyl)-phthalide.

3.3-bis(ρ-dimethylaminophenyl)-6-dimethylaminophthalide (also known as crystal violet lactone), 3.3-bis(p-dimethylaminophenyl)-6-dibutylaminophenyl.

3.3-bis(p-dimethylaminophenyl)-6-chlorophthalide, 3.3-bis(p-dibutylaminophenyl)phthalide, 3-cyclohexylamino-6-chlorofluorane, 3-dimethylamino-5, 7-dimethylfluorane, 3
-diethylamino-7-chlorofluorane, 3-diethylamino-7-methylfluorane, 3-diethylamino-7,8-benzfluorane, 3-diethylamino-6
-Methyl-7-chlorofluorane, 3=(N-p-hly-N-ethylamino)-6-methyl-7-anilitofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 2 - (N-(3'-trifluoromethylphenyl)
amino)-6-dinithylaminofluorane, 2-(3
, 6-bis(diethylamino)-9-(o-chloroanilino)xantylbenzoic acid lactam), 3-diethylamino-6-methyl-7-(m-trichloromethylanilino)fluoran.

3-diethylamino-7-(o-chloroanilino)fluorane, 3-dibutylamino-7-(o-chloroanilinofluorane, 3N-methyl-N-amylamino-6-methyl-7-anilinofluorane, 3- N-Methyl-N-cyclohexylamino-6-methyl-7-anilinofluorane, 3-diethylamino-6-methyl-7-anilinofluorane, 3-(~,N-diethylamino)-5-methyl- 7-(
N.

N-dibenzylamino)fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-pyrylospirane, 6'-bromo-3'-methoxy-benzoindolino-pyrylospirane, 3-(2'- Hydroxy-4'-dimethylaminophenyl)-3-(2'-Me1-xy5'-chlorophenyl)phthalide, 3-(2'-Hydroxy-4'-dimethylaminophenyl)-3-(2'- Methoxy-5'-nitrophenyl) phthalide, 3-(2'-hydroxy-4'-diethylaminophenyl)-3-(2'-methoxy-57-methylphenyl) phthalide, 3-(2'-methoxy-4 '-dimethylaminophenyl)-3-(2'-hydroxy-4'-chloro-5'
-methylphenyl)phthalide.

3-morpholino-7-(N-propyl-trifluoromethylanilino)fluorane, 3-pyrrolidino-7-trifluoromethylanilinofluorane, 3-diethylamino-5-chloro-7-(N-benzyl-trifluoro methylanilino) fluorane.

3-pyrrolidino-7-(di-p-chlorophenyl)methylaminofluorane, 3-diethylamino-5-chloro-7-(α-phenylethylamino)fluoran, 3-(N-ethyl-P-1-luidino) )-7-(α-phenylethylamino)fluoran, 3-diethylamino-7-(0-methoxycarbonylphenylamino)fluoran, 3-diethylamino-5-methyl-7-(α-phenylethylamino)fluoran.

3-diethylamino-7-piperidinofluorane, 2-
Chloro-3-(N-methyl 1-luidino)-7-(p-
〇-Butylanilino)fluorane, 3-(N-benzyl-N-cyclohexylamino)-5
, 6-penzo 7-α-naphthylamino-4'-bromofluorane, 3-diethylamino-6-methyl-7-mesitidino 4
',5'-benzofluorane etc.

In the present invention, the above-mentioned coloring agent is used, but other coloring agents can be used in combination if necessary. In this case, the coloring agent used in combination includes various coloring agents that cause the leuco dye to develop color upon contact. An electron-accepting compound, an oxidizing agent, or the like is applied. Such substances are conventionally known, and specific examples thereof include inorganic acids, organic acids, phenolic substances, phenolic resins, etc. as shown below.

Pen 1 ~ night, zeolite, acid clay, activated clay, silica gel, salicylic acid, 3-cert, -butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, di-
m-chlorophenylthiourea, di-m-trifluoromethylphenylthiourea, di-phenylthiourea, salicylanilide, 4,4'-isopropylidene diphenol, 4,4'-isopropylidene bis(2-chlorophenol), 4 , 4'-isopropylidene bis(2,6-dibromophenol), 4.4'-isopropylidene bis(2,6-dichlorophenol), 4.4'-isopropylidene bis(2-methylphenol), 4, 4'-isopropylidene bis(2,6-dimethylphenol),
4,4'-isopropylidene bis(2-tert-butylphenol), 4,4'-5ac-butylidene diphenol, 4,4'-cyclohexylidene bisphenol, 4,4'-cyclohexylidene bis(2-methyl phenol), 4-jet-butylphenol, 4-
phenylphenol, 4-hydroxydiphenoxide,
α-naphthol, β-naphthol, 3,5-xylenol, thymol, methyl-4-hydroxybenzony 1
-14-hydroxyace1-phenone, novolac type phenolic resin, 2,2'-thiobis(4,6-dichlorophenol), catechol, resorcinol, hydroquinone, pyrogallol, phloroglycine, phloroglycine carboxylic acid, 4-cycrt- Octylcatechollenbis(4-chlorophenol), 2,2'-methylenebis(
4-methyl-6-art-butylphenol),
2,2'-dihydroxydiphenyl, ethyl P-hydroxybenzoate, propyl P-hydroxybenzoate, P-
Butyl hydroxybenzoate, benzyl p-hydroxybenzoate, p-chlorobenzyl p-hydroxybenzoate, p-hydroxyambu, 〇-chlorobenzyl fragrant, p
-Hydroxybenzoic acid-P-methylbenzyl, P-hydroxybenzoic acid-n-octyl, benzoic acid, 1-hydroxy-2-naphthoic acid, 2-hydroxy-6-naphthoic acid, 4-hydroxydiphenylsulfone, 4-hydroxy -47-chlorodiphenylsulfone, bis(4-hydroxyphenyl)sulfide, 2-hydroxy-P-toluic acid, tartaric acid, oxalic acid, maleic acid, citric acid.

Succinic acid, stearic acid, 4-hydroxyphthalic acid, boric acid, biimidazole, hexaphenylbiimidazole, carbon tetrabromide, etc.

In the present invention, when a leuco dye and a coloring agent are bonded and supported on a support in order to obtain a heat-sensitive recording material, various conventional binders can be used as appropriate. Specific examples of such binders include the following.

Polyvinyl alcohol, starch and its derivatives, cellulose derivatives such as methoxycellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate,
Polyvinylpyrrolidone, acrylic amide/acrylic ester copolymer, acrylic amide/acrylic ester/methacrylic acid ternary copolymer, styrene/maleic anhydride copolymer alkali salt, inbutylene/maleic anhydride copolymer In addition to water-soluble polymers such as alkali salts, polyacrylamide, sodium alginate, gelatin, and casein, polyvinyl acetate, polyurethane, styrene/butadiene copolymer, polyacrylic acid, polyacrylic acid ester, vinyl chloride/vinyl acetate copolymer latexes such as polybutyl methacrylate-1-, ethylene/vinyl acetate copolymer, styrene/butadiene/acrylic copolymer, etc.

In addition, in the present invention, if necessary, auxiliary additive components commonly used in this type of heat-sensitive recording material, such as fillers, surfactants, thermofusible substances, lubricants, pressure color prevention agents, etc., may be used in combination. I can do it. In this case, fillers include, for example, inorganic fine powders such as calcium carbonate, silica, titanium oxide, barium sulfate, clay, talc, and surface-treated calcium and silica, as well as urea-formalin resin, styrene/
Examples include fine organic powders such as methacrylic acid copolymers and polystyrene resins, and examples of lubricants include higher fatty acids and their metal salts, higher fatty acid amides, high paper fatty acid esters, animal-based, vegetable-based, and mineral-based. Alternatively, various petroleum-based waxes may be used.

In the present invention, when producing a heat-sensitive recording material, a dispersion of a leuco dye and a coloring agent obtained by dispersing them separately is mixed with an appropriate binder, and this mixture is coated on a support such as paper. do.

According to the present invention, a thermal transfer type thermal recording material in which a leuco dye and a coloring agent are supported on separate supports is also provided. Dissolve. A transfer sheet is formed by applying the coloring agent to a support of a heat-resistant sheet, such as a polyester film, while a coloring agent is dispersed or dissolved in water or a solvent and applied to the support to form a receptor sheet.

The heat-sensitive recording material of the present invention can be used in various fields like conventional ones, but in particular, it can be used in optical character readers and label barcoders by taking advantage of its excellent near-infrared light absorption properties. - Can be used as a recording material for reading records with a barcode reader.

In addition, when the recording material of the present invention is used as heat-sensitive recording type label sheet 1~, a heat-sensitive coloring layer containing the above-mentioned leuco dye and coloring agent is provided on one side of the support, and is adhered to the other side of the support. It is sufficient to have a structure in which a release mount is provided through an agent layer, and in this case, a protective layer such as a water-soluble resin layer is provided on the surface of the heat-sensitive coloring layer, if necessary, in order to improve image stability. You can also do that.

The leuco dye represented by the general formula (I) used in the present invention can be obtained by reducing the carbonyl group of bis(p-disubstituted aminobenzal)acetone with a carbonyl reducing agent, for example, lithium aluminum hydride, and at the same time reducing the carbonyl group with an acid such as perchloric acid. In addition, a bis(P-disubstituted aminostyryl)carbeniram salt is prepared, and then an organic sulfinic acid sodium salt is added to this salt and reacted.

〔effect〕

The heat-sensitive recording material of the present invention uses a leuco dye represented by the general formula (1), and as a coloring agent, a leuco dye represented by the general formula (II)
Alternatively, by using a compound represented by general formula (m) and a transition metal compound, the colored image absorbs the near-infrared region, and the image is read by an image reading device using a general-purpose semiconductor laser. In addition, the resulting images have high density, excellent image reliability, and excellent oil resistance.

〔Example〕

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 Solutions CA) to (E) were prepared by dispersing each liquid mixture having the following composition using a sand grinder for 1 to 2 hours.

[Liquid A]

Bis(p-dimethylaminostyryl)-p-methylphenylsulfonylmethane 10 parts 10% polyvinyl alcohol aqueous solution 10 parts water
80Il [B
Liquid] Stearic acid amide 20 parts 5%
Methylcellulose aqueous solution '1Qtt water
60
II [Liquid C] Calcium carbonate 30 parts 5% -
Methylcellulose aqueous solution 30Il water
40
1I [Liquid D] Zinc stearate 20 parts 5%-
Methylcellulose aqueous solution 20I/water
60
/I [Liquid E] 10% polyvinyl alcohol aqueous solution 20 parts water

60II Next, [Liquid A], [Liquid B], [Liquid C], [Liquid D]
, [Liquid E] were mixed in a ratio of 1:1 near: 2:3 to create a coating liquid, and this coating liquid was applied to a high-quality paper with a basis weight of 50 g/m with a dry adhesion amount of dye of 0.6 g/rrl. '' and dried to obtain a heat-sensitive recording material.

Example 2 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that zinc stearate in the solution CD) in Example 1 was replaced with aluminum stearate.

Example 3 Solution E of Example 1 A thermosensitive recording material was obtained in the same manner as in Example 1.

Example 4 Example 1 (EE liquid) A thermosensitive recording material was obtained in the same manner as in Example 1.

Comparative Example 1 Bis(P-dimethylaminostyryl)-P-methylphenylsulfonylmethane of liquid [A] of Example I.

A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except that 3N-cyclohexylamino-6-methyl-7-anilinofluorane was used.

Comparative Example 2 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1 except that [liquid D] in Example 1 was omitted.

Comparative Example 3 A comparative heat-sensitive recording material was obtained in the same manner as in Example 1, except that liquid (E) in Example 1 was replaced with bisphenol A.

Next, the color density, background density, oil resistance, and PC5 value of the heat-sensitive recording material thus obtained were measured.

(1) Color density: 1 at 130°C using a thermal gradient tester.
After contacting for seconds (applied pressure: 2, 0 kg/cri), measurement was performed using a Macbeth densitometer RD-514 (filter: Wratten 106 or Wratten 25).

(2) Background density: Macbeth densitometer RD − for non-image areas
514 (filter is Wratten 106).

(3) Oil resistance 2 Cottonseed oil was attached to the sample used for the color density, and after leaving it at 40°C for 15 hours, the image area was measured with a Macbeth densitometer RD-514 (filter 106 or filter 25).

(4) PC3 value 2 After measuring the reflectance at 900 nm of the image area and non-image area of the sample used for color density using a spectrophotometer, the PC5 value was calculated using the following formula.

T (background) - D (image) PCS value =
The psc value at 0 nm is high, making it practical (70% or more is required for practical use), and the coloring density is high, and the oil resistance is also superior to that of comparative products.

Claims (1)

[Claims] (1) In a heat-sensitive recording material that utilizes a color-forming reaction between a leuco dye and a coloring agent that causes the leuco dye to develop color upon contact, at least one of the leuco dyes has the following general formula (
I), wherein at least one of the color formers is a compound represented by the following general formula (II) or general formula (III), and further contains a transition metal compound. Heat-sensitive recording material. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (I) (In the formula, R_1, R_2, R_3, R_4 are hydrogen or substituted or unsubstituted alkyl groups, R_5, R_6 are hydrogen or substituted or unsubstituted phenyl groups, R_7 is a substituted or unsubstituted alkyl group or a substituted or unsubstituted phenyl group) ▲There are numerical formulas, chemical formulas, tables, etc.▼(II) (R_8 is -COOR_9, -COR_1_0, -CH
O, represents halogen, hydrogen atom, in this case R_9,
R_1_0 represents an optionally substituted aryl group, aralkyl group, alkyl group, or alkoxy group. n is the number of substituents and is an integer of 1 to 3; in this case, the types of substituents may be different. ) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(III) (▲There are mathematical formulas, chemical formulas, tables, etc.▼ is a benzene ring or naphthalene ring, and R_1_1 is a hydrogen atom, halogen, or an alkyl group with 1 to 4 carbon atoms, alkoxy Represents a group.n
is the number of substituents, n = an integer of 1 to 4, and in this case, the types of substituents may be different)