JPH05169824A - Thermal recording material - Google Patents

Abstract

PURPOSE:To reduce the fog of a blank part by using a compound represented by a specific chemical formula as a basic dye in a thermal recording layer and providing an intermediate layer containing basic pigment between a support and the thermal recording layer. CONSTITUTION:In a thermal recording material utilizing the color forming reaction of the colorless or light-colored basic dye and inorg. or org. developer contained in the thermal recording layer provided on a support and bringing both color forming substances into contact with each other under heating to obtain a recording image, at least one kind of a compound represented by chemical formula (wherein R1 and R2 are a halogen atom, a 1-4C alkyl group or a 1-25C alkoxy group, and R3 is a 1-25C halogenoalkyl group, a phenyl group which may be substituted or a benzyl group) is used as the basic dye. Further, in this thermal recording material, an intermediate layer containing basic pigment such as heavy calcium carbonate or magnesium carbonate is provided between the support and the thermal recording layer.

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 yellow-coloring heat-sensitive recording material with less fog on a white paper portion.

[0002]

2. Description of the Related Art A heat-sensitive recording material which utilizes a color reaction between a colorless or light-colored basic dye and an organic or inorganic color-forming agent to bring a recording image by contacting both color-forming substances with heat is often used. Are known. Such a thermal recording material is relatively inexpensive,
Since the recording device is compact and easy to maintain, it is used not only as a recording medium for facsimiles and various computers, but also in a wide range of fields. In recent years, a thermal recording material is often used also as an output for a word processor, and a thermal recording paper which develops various colors such as red and blue has been demanded.

[0003]

DISCLOSURE OF THE INVENTION The inventors of the present invention have conducted various studies to provide a heat-sensitive recording material that develops yellow, but a basic dye that develops yellow in general has a low coloring density and is resistant to light of a colored image. Inferior in sex. Also, JP-A-59-1528
No. 91 and JP-A No. 62-70081 exemplify a basic dye of yellow coloration which is excellent in light resistance, but it was found that the fogging on the white paper part was remarkable depending on the support used.

[0004]

DISCLOSURE OF THE INVENTION The inventors of the present invention have earnestly studied to provide a yellow color heat-sensitive recording material having less fog on a white paper portion, and as a result, a specific dye was used to specify a specific color between a support and a recording layer. It has been found that the problem can be solved by providing an intermediate layer containing the pigment.

That is, the present invention provides a heat-sensitive recording material comprising a support and a heat-sensitive recording layer containing a colorless or light-colored basic dye and a color-forming agent capable of developing a color by contacting with the dye. A heat-sensitive recording material comprising at least one compound represented by the following general formula [Chemical Formula 1] as a photosensitive dye, and an intermediate layer containing a basic pigment provided between the support and the heat-sensitive recording layer. Is.

[0006]

[Chemical 1]

(Wherein R ₁ and R ₂ are halogen atoms, and C ₁ to
C ₄ alkyl group, C ₁ -C ₂₅ alkoxy group,
R ₃ represents a C _{1 to} C ₂₅ alkyl group, a C _{1 to} C ₂₅ alkoxyalkyl group, a C _{1 to} C ₂₅ halogenoalkyl group, an optionally substituted phenyl group, or an optionally substituted benzyl group, m and n show the integer of 0, 1, and 2. )

[0008]

Specific examples of the basic dye represented by the general formula [Chemical Formula 1] used in the present invention include 1- (4-methoxyphenyl) -2- (2-quinolyl) ethylene and 1- (4- Octoxyphenyl) -2- (2-quinolyl) ethylene,
1- (3-methoxy-4-lauryloxyphenyl)-
2- (2-quinolyl) ethylene, 1- (4-methoxyphenyl-2- (6-ethoxy-2-quinolyl) ethylene, 1- (4-myristyloxyphenyl) -2- (2-
Examples thereof include compounds such as quinolyl) ethylene and 1- (3-methoxy-4-myristyloxyphenyl) -2- (6-ethoxy-2-quinolyl) ethylene, but are not limited to these compounds, and are generally Two or more compounds represented by the formula [Chemical Formula 1] may be used in combination.

Various compounds are known as the color former used in combination with the specific basic dye used in the present invention, and examples thereof include the following. 4-tert-butylphenol, α-naphthol, β-naphthol, 4-acetylphenol, 4-tert-octylphenol,
4,4'-sec-butylidene diphenol, 4-phenylphenol, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenyl ether, 4,
4'-isopropylidene diphenol, hydroquinone, 4,4'-cyclohexylidene diphenol, 4,
4 '-(1,3-dimethylbutylidene) bisphenol, 2,2-bis (4-hydroxyphenyl) -4-methylpentane, 4,4'-dihydroxydiphenyl sulfide, 4,4'-thiobis (6-tert -Butyl-3
-Methylphenol), 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-methoxydiphenylsulfone, 4-hydroxy-4. ′ -Isopropoxydiphenyl sulfone, 4-hydroxy-3 ′, 4′-trimethylene diphenyl sulfone, 4-hydroxy-3 ′, 4′-tetramethylene diphenyl sulfone, 3,4-dihydroxy-4′-methyldiphenyl sulfone, Bis (3-allyl-4-hydroxyphenyl) sulfone, 1,3-di [2- (4-hydroxyphenyl) -2-propyl] benzene, 1,1-bis (4-hydroxyphenyl) -1
-Phenylethane, hydroquinone monobenzyl ether, bis (4-hydroxyphenyl) acetic acid butyl ester, 4-hydroxybenzophenone, 2,4-dihydroxybenzophenone, 2,4,4'-trihydroxybenzophenone, 2,2 ', 4 4'-tetrahydroxybenzophenone, dimethyl 4-hydroxyphthalate, 4
-Methyl hydroxybenzoate, ethyl 4-hydroxybenzoate, propyl 4-hydroxybenzoate, sec-butyl 4-hydroxybenzoate, pentyl 4-hydroxybenzoate, phenyl 4-hydroxybenzoate, benzyl 4-hydroxybenzoate. Tolyl 4-hydroxybenzoate, chlorophenyl 4-hydroxybenzoate, phenylpropyl 4-hydroxybenzoate, phenethyl 4-hydroxybenzoate, p-chlorobenzyl 4-hydroxybenzoate, p-methoxy 4-hydroxybenzoate. Phenolic compounds such as benzyl, novolac type phenol resin, phenol polymer, benzoic acid, p-tert-butylbenzoic acid, trichlorobenzoic acid, terephthalic acid, 3-se
c-Butyl-4-hydroxybenzoic acid, 3-cyclohexyl-4-hydroxybenzoic acid, 3,5-dimethyl-4
-Hydroxybenzoic acid, salicylic acid, 3-isopropylsalicylic acid, 3-tert-butylsalicylic acid, 3,5-di-tert-butylsalicylic acid, 3-benzylsalicylic acid,
3- (α-methylbenzyl) salicylic acid, 3-chloro-
5- (α-methylbenzyl) salicylic acid, 3-phenyl-5- (α, α-dimethylbenzyl) salicylic acid, 3,
5-di-α-methylbenzyl salicylic acid, 4- (2-p
-Methoxyphenoxyethoxy) salicylic acid, 4- (3
-P-tolylsulfonylpropyloxy) salicylic acid,
Aromatic carboxylic acids such as 5- [p- (2-p-methoxyphenoxyethoxy) cumyl] salicylic acid, and these phenolic compounds, aromatic carboxylic acids and, for example, zinc,
Organic acidic substances such as salts with polyvalent metals such as magnesium, aluminum, calcium, titanium, manganese, tin and nickel. As a matter of course, two or more kinds of the above-mentioned color developing agents can be used in combination.

The use ratio of the basic dye and the color developing agent should be appropriately selected according to the type of the color developing agent and is not particularly limited, but generally 100 to 2000 per 100 parts by weight of the basic dye. Parts by weight, preferably 150-1500
About a part by weight of the coloring agent is used. The preparation of a coating liquid containing these is generally carried out by using water as a dispersion medium and dispersing the dye, the specific polyvalent metal salt, and the color former together or separately by a stirring / grinding machine such as a ball mill, an attritor or a sand mill. It is prepared, for example.

In such a coating liquid, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol, carboxy group-modified polyvinyl alcohol, sulfo group-modified polyvinyl alcohol, silicon modified polyvinyl alcohol are usually used as binders. ,
Acetoacetyl group-modified polyvinyl alcohol, graft copolymer of vinyl alcohol / vinyl acetate copolymer and acrylamide / acrylic acid / allyl acetoacetate copolymer, diisobutylene / maleic anhydride copolymer salt, styrene / maleic anhydride Copolymer salt, ethylene
Acrylic acid copolymer salt, styrene-acrylic acid copolymer salt, styrene-butadiene copolymer emulsion, colloidal silica particle composite styrene-acrylic acid ester copolymer emulsion, urea resin, melamine resin, amide resin, etc. are all solid 1-40% by weight, preferably 5-2
About 5% by weight is blended. Of course, it is also possible to use two or more kinds of these binders.

Further, various auxiliaries can be added to the coating solution, for example, 2,2'-methylenebis (4,6-
Mixture of sodium salt of di-tert-butylphenyl) phosphate and magnesium silicate, dioctylsulphosuccinic acid sodium salt, sodium dodecylbenzenesulfonic acid salt, lauryl alcohol sulfate / sodium salt, dispersant such as fatty acid metal salt, benzophenone system,
Examples include cyanoacrylate-based and hydroxybenzoate-based ultraviolet absorbers, other defoaming agents, fluorescent dyes, coloring dyes, and the like.

Further, stearic acid ester wax, polyethylene wax, carnauba wax, microcrystalline wax, so as to prevent the thermal recording material from sticking due to contact with a recording device or recording head.
It is also possible to add a dispersion or emulsion of carboxy-modified paraffin wax, zinc stearate, calcium stearate or the like.

In addition, kaolin, clay, talc, calcium carbonate,
Magnesium carbonate, calcined clay, titanium oxide, diatomaceous earth,
Inorganic pigments such as particulate anhydrous silica and activated clay, organic pigments such as styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler, and raw starch granules can also be added.

Further, in the heat-sensitive recording material of the present invention, fatty acids such as stearic acid amide, stearic acid methimon bisamide, oleic acid amide, palmitic acid amide, and coconut fatty acid amide are used as long as the desired effects of the present invention are not impaired. Amide, 4,4'-butylidene bis (6-tert
-Butyl-3-methylphenol), 1,1,3-tris (2-methyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (2-methyl-4)
Hindered phenols such as -hydroxy-5-cyclohexylphenyl) butane, m-terphenyl, p-benzylbiphenyl, p- (4-tolyloxy) biphenyl, 1,5-bis (4-methoxyphenoxy) -3-oxa -Pentane, 1,2-bis (phenoxy) ethane,
1,2-bis (4-methylphenoxy) ethane, 1,2
-Bis (3-methylphenoxy) ethane, 1- (2-methylphenoxy) -2- (4-methoxyphenoxy) ethane, ethers such as 2-naphtholbenzyl ether, dibenzyl terephthalate, 1-hydroxy-2-
Naphthoic acid phenyl ester, oxalic acid dibenzyl ester, oxalic acid di (4-methylbenzyl) ester, oxalic acid di (4-chlorobenzyl) ester, etc., 2- (2'-hydroxy-5'-methylphenyl) )
An ultraviolet absorber such as benzotriazole and 2-hydroxy-4-benzyloxybenzophenone and various known heat-fusible substances can be used together as a sensitizer.

Regarding the amount of the heat-fusible substance used,
Although not particularly limited, it is generally 50 to 1000 parts by weight, preferably 1 to 100 parts by weight of the basic dye.
It is preferably used in the range of 00 to 500 parts by weight.

In the heat-sensitive recording material of the present invention, the method for forming the recording layer is not particularly limited, and the recording layer can be formed according to a conventionally known and commonly used technique. For example, the coating solution for the heat-sensitive recording layer, the intermediate layer provided on the support is coated with an appropriate coating device such as an air knife coater, a blade coater, a bar coater, a die coater, a gravure coater, a curtain coater, and a short dwell coater. Dry to form a recording layer. Further, the coating amount of the coating liquid is not particularly limited, and is generally about 1.0 to 12 g / m ² in dry weight, preferably 1.5 to 10 g.
It is adjusted in the range of / m ² .

In the present invention, the intermediate layer provided between the support and the heat-sensitive recording layer as described above is generally prepared by mixing a basic pigment and a binder to prepare an aqueous coating solution for the intermediate layer, and preparing an acidic paper or medium. It is formed by a method of applying and drying it on a support such as paper such as functional paper, plastic film, synthetic paper, non-woven fabric sheet, and molded product.

The basic pigment used in the intermediate layer includes
Heavy calcium carbonate, light calcium carbonate, magnesium carbonate, barium carbonate, satin white and the like are preferable,
Particularly, heavy calcium carbonate, light calcium carbonate, and magnesium carbonate are more preferable for obtaining a desired effect. It should be noted that these basic pigments may be used in combination of two or more, if necessary.

The binder used in the coating liquid for the intermediate layer is, for example, starch, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, gelatin, casein, gum arabic, polyvinyl alcohol,
Examples thereof include a styrene / maleic anhydride copolymer salt and a styrene / butadiene copolymer emulsion.

The use ratio of the basic pigment and the binder is not particularly limited, but in order to obtain the desired effects of the present invention, 50% by weight or more of the solid content of the intermediate layer is the basic pigment. Is preferred, and particularly basic pigment 10
2 to 40 parts by weight, most preferably 5 to 0 parts by weight
It is desirable to incorporate 25 parts by weight of binder. Further, various auxiliary agents can be added to the coating liquid for the intermediate layer, and examples of such auxiliary agents include dioctylsulfosuccinic acid sodium salt, dodecylbenzenesulfonic acid sodium salt, lauryl alcohol sulfate / sodium salt, and fatty acid. Dispersants such as metal salts, stearic acid, polyethylene, carnauba wax, paraffin wax, zinc stearate, calcium stearate, lubricants such as emulsions and emulsions, UV absorbers such as triazoles, other defoamers, fluorescent Examples thereof include dyes and coloring dyes. Furthermore, if necessary in the coating liquid,
Ordinary inorganic pigments and organic pigments may be added within a range that does not impair the desired effects of the present invention.

The coating solution for the intermediate layer thus prepared is
Ordinary air knife coater, bar coater, blade coater
Tar, short dwell coater, curtain coater, etc.
Is coated and dried on a support by a known coating device of
An intermediate layer is formed. The amount of coating is also limited
Although it does not, 0.5 to 12 g / m in dry weight ²
It is desirable to adjust it to be within the range.

In the present invention, a protective layer may be formed on the heat-sensitive recording layer to improve the storage stability. Examples of the water-soluble or water-dispersible polymer used for forming the protective layer include various binders as described above. Among them, acetoacetyl group-modified polyvinyl alcohol and carboxyl group-modified porvinyl alcohol are
It is particularly preferably used because it forms a strong film.

A pigment may be added to the protective layer, if necessary, in order to further improve printability and sticking. Specific examples thereof include calcium carbonate,
Inorganic pigments such as zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, and colloidal silica, styrene microballs, nylon powder, polyethylene powder, ureapolmarin. Examples include resin fillers and organic pigments such as raw starch particles. The amount used is generally 5 to 5 with respect to 100 parts by weight of the resin component.
It is desirable to adjust within the range of about 00 parts by weight.

Furthermore, in the coating liquid for forming the protective layer, zinc stearate, calcium stearate,
Lubricants such as polyethylene wax, carnauba wax, paraffin wax and ester wax; surfactants (dispersants, lubricants) such as sodium dioctylsulfosuccinate; antifoaming agents; water-soluble polyvalent salts such as potassium alum and calcium acetate. Various auxiliaries can also be added as appropriate.
Further, a curing agent such as glyoxal, boric acid, dialdehyde starch, or an epoxy compound may be added to further improve water resistance. The coating liquid for forming the protective layer is generally prepared using water as a dispersion medium.

The coating solution for protective layer thus prepared is coated on the thermosensitive recording layer by an appropriate coating layer, but when the coating amount exceeds 20 g / m ² in dry weight, the recording sensitivity of the thermosensitive recording medium is remarkably lowered. Generally, 0.1-20
g / m ^2, preferably it is desired to be adjusted in the range of about 0.5 to 10 g / m ^2.

The heat-sensitive recording material of the present invention may be a multi-color heat-sensitive recording material by combining heat-sensitive recording layers which develop different color tones. Further, if necessary, a protective layer may be provided on the back side of the thermosensitive recording medium to further improve the storability. Furthermore, it is also possible to apply a super calendar after coating each layer, and various known techniques in the thermal recording material manufacturing field can be applied as necessary, such as applying an adhesive treatment to the back surface of the recording material and processing it into an adhesive label. It can be added.

[0028]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In addition, "part" and "%" in an example show "weight part" and "weight%", respectively, unless there is particular notice.

Example 1 Formation of Intermediate Layer 100 parts of light calcium carbonate (trade name: Callite SA, manufactured by Shiraishi Kogyo Co., Ltd.), styrene-butadiene copolymer emulsion (product life: Dow-1571, solid content concentration: 48%, Asahi Dow Co., Ltd. 20 parts, polyvinyl alcohol (trade name: PV
A-105 (manufactured by Kuraray Co., Ltd.) was mixed with 150 parts of a 4% aqueous solution and 80 parts of water to obtain a coating solution, which was obtained by acidic papermaking at 64 g / m ^2.
Coating amount of 5g after drying with air knife coater
/ M ² and then dried and super calendered to form an intermediate layer.

Preparation of Solution A 1- (3-methoxy-4-lauryloxyphenyl)-
A composition comprising 10 parts of 2- (2-quinolyl) ethylene, 25 parts of 1,2-bis (3-methylphenoxy) ethane, 15 parts of a 5% aqueous solution of methylcellulose, and 35 parts of water was used, and the average particle size was adjusted to 0. It was crushed to 8 μm.

Preparation of Solution B 4,4′-Cyclohexylidenediphenol 30 parts, 5
% 15% aqueous solution of methyl cellulose and 45 parts of water were pulverized with a sand mill until the average particle size became 1.1 μm.

Preparation of Recording Layer Liquid A 85 parts, liquid B 90 parts, light calcium carbonate (oil absorption 90 ml / 100 g) 30 parts, 20% polyvinyl alcohol aqueous solution 75 parts, 30% zinc stearate aqueous dispersion 15
And 170 parts of water were mixed and stirred to obtain a coating liquid. The resulting coating liquid was applied and dried on the support so that the coating amount after drying was 8 g / m ² , to obtain a heat-sensitive recording material.

Examples 2 to 4 In the preparation of solution B, 2,4'-dihydroxydiphenylsulfone (Example 2) and 4-hydroxy-4'-isopropoxydiphenylsulfone were used instead of 4,4'-cyclohexylidenediphenol. A thermosensitive recording medium was obtained in the same manner as in Example 1 except that (Example 3) and 1,1-bis (4-hydroxyphenyl) -1-phenylethane (Example 4) were used.

Example 5 In preparation of solution A, 1- (4-myristyloxyphenyl) -2- was used instead of 1- (3-methoxy-4-lauryloxyphenyl) -2- (2-quinolyl) ethylene.
A thermosensitive recording medium was obtained in the same manner as in Example 1 except that (2-quinolyl) ethylene was used.

Comparative Example 1 A thermosensitive recording medium was obtained in the same manner as in Example 1 except that the intermediate layer was not provided. Comparative Example 2 A thermosensitive recording medium was obtained in the same manner as in Example 2 except that the intermediate layer was not provided. Comparative Example 3 A thermosensitive recording medium was obtained in the same manner as in Example 3 except that the intermediate layer was not provided. Comparative Example 4 A thermosensitive recording medium was obtained in the same manner as in Example 4 except that the intermediate layer was not provided. Comparative Example 5 A thermosensitive recording medium was obtained in the same manner as in Example 5 except that the intermediate layer was not provided.

Example 6 In the preparation of the intermediate layer of Example 1, 100 parts of light calcium carbonate (trade name: Callite SA, manufactured by Shiraishi Industry Co., Ltd.) was replaced with heavy calcium carbonate (Softon 1500, manufactured by Bihoku Kouka Co., Ltd.). ) A thermosensitive recording medium was obtained in the same manner as in Example 1 except that 100 parts were used.

Example 7 In the preparation of the intermediate layer of Example 1, 100 parts of magnesium carbonate (manufactured by Kyowa Chemical Co., Ltd.) was used in place of 100 parts of light calcium carbonate (trade name: Callite SA, manufactured by Shiraishi Industry Co., Ltd.). A thermosensitive recording medium was obtained in the same manner as in Example 1 except for the above.

Macbeth reflection densitometers (RD-914 type, manufactured by Macbeth Co., yellow filter) were used to measure the densities of 12 kinds of heat-sensitive recording media obtained as described above after 10 days on the blank area.
The results are shown in [Table 1].

[0039]

[Table 1]

[0040]

As is clear from the results of [Table 1], the heat-sensitive recording materials obtained in the respective examples of the present invention were all heat-sensitive recording materials with less fog on the blank area.

Claims (1)

[Claims] 1. A thermosensitive recording medium comprising a support and a thermosensitive recording layer containing a colorless or light-colored basic dye and a coloring agent capable of coloring when contacted with the dye. A thermosensitive recording medium comprising at least one compound represented by the following general formula [Chemical Formula 1] and an intermediate layer containing a basic pigment provided between the support and the thermosensitive recording layer. [Chemical 1] (In the formula, R ₁ and R ₂ represent a halogen atom, a C _{1 to} C ₄ alkyl group, and a C _{1 to} C ₂₅ alkoxy group, and R ₃ represents C ₁ to
C ₂₅ alkyl group, C ₁ -C ₂₅ alkoxyalkyl group, C ₁ -C ₂₅ halogenoalkyl group, optionally substituted phenyl group, optionally substituted benzyl group,
m and n show the integer of 0, 1, and 2. )