JP2752364B2 - Thermal recording material - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermosensitive recording material, and more particularly to a thermosensitive recording material having improved head matching.

[Prior art] A thermosensitive recording material is generally provided with a thermochromic layer mainly composed of a thermochromic composition on a support such as paper, synthetic paper, or plastic film. By heating, a colored image is obtained.

Compared to other recording materials, this type of recording material can be obtained in a short time with a relatively simple apparatus without performing complicated processing such as development and fixing, and has a low noise generation and environmental pollution.
Because of its advantages such as low cost, it is widely used as a recording material in various fields such as electronic calculators, facsimile machines, ticket vending machines, labels, and recorders, in addition to being used for copying books and documents. The thermochromic composition used for such a thermosensitive recording material generally comprises a color former and a color developer which causes the color former to develop color when heated.Examples of the color former include a colorless or colorant having a lactone, lactam or spiropyran ring. A light-colored leuco dye is used, and as a developer, various acidic substances such as organic acids and phenolic substances are used.

The recording material obtained by combining the color former and the developer is particularly advantageous in that the color tone of the obtained image is clear, the whiteness of the background is high, and the weather resistance of the image (dye image) is excellent. It is widely used.

In recent years, as thermal recording materials have replaced other conventional recording methods and their demand has increased, the demand for quality improvement of the thermal recording materials used in this thermal recording method has been increasing. There is a demand for a heat-sensitive recording material which is excellent in head matching without affecting head life. As a method of improving the head matching, a method of providing an overcoat layer containing a filler having a large oil absorption and a lubricant such as zinc stearate and aluminum stearate is known.However, when an overcoat layer is provided, In printing, the heat-sensitive coloring layer comes into contact with the thermal head via the overcoat layer, so that heat conduction is hindered and the coloring property is reduced.

In recent years, high-speed recording of heat-sensitive recording materials has progressed, and improvement in thermal responsiveness has been desired. Therefore, the amount of the overcoat layer has to be reduced, and satisfactory results have not been obtained.

[Purpose] It is an object of the present invention to provide a heat-sensitive recording material which is free from sticking and scum sticking troubles and has an excellent head matching property with very little influence on the head life.

[Constitution] According to the present invention, a thermosensitive recording material comprising a leuco dye and a developer provided on a support, and an overcoat layer provided thereon is provided. And a compound represented by the following general formula [I].

(Where R ₁ and R ₂ are each _{H 2 C = CH-CH 2} -, X is SO ₂ , Is shown. However, when X is SO ₂ , R ₁ and R ₂ are The present invention mainly has a feature that the compound represented by the general formula [I] is contained in the overcoat layer as described above.

Specific examples of the compound represented by the general formula [I] include bisphenol S diacrylate and bisphenol A
Diacrylate, bisphenol S dimethacrylate,
Bisphenol A dimethacrylate, Bisphenol A
Diglycidyl ether, bisphenol A diallyl ether, bisphenol S diallyl ether, bis (4-
Allyloxyphenyl) sulfide, bis (4-glycidyloxyphenyl) sulfide, bis (4-acryloyloxyphenyl) sulfide and the like can be mentioned.

The overcoat layer of the present invention is formed by applying and drying the compound represented by the above general formula [I] together with a binder on the thermosensitive coloring layer. Examples of the binder used in the overcoat layer include methylcellulose and methoxycellulose. , Hydroxyethyl cellulose, carboxymethyl cellulose, sodium carboxymethyl cellulose,
Cellulose, polyvinyl alcohol, carboxy group-modified polyvinyl alcohol, sulfonic acid group-modified polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylic acid, starch and derivatives thereof, casein, gelatin water-soluble isoprene rubber, styrene / maleic anhydride copolymer Water-soluble ones such as alkali salts of alkali salt iso (or diiso) butylene / maleic anhydride copolymer or polyvinyl acetate, vinyl chloride / vinyl acetate copolymer, polystyrene, polyacrylate, polyurethane, styrene / butadiene Water-soluble emulsions such as copolymers, carboxylated styrene / butadiene copolymers, and styrene / butadiene / acrylic acid copolymers are used.

If necessary, auxiliary additives such as fillers and lubricants can be used in combination. In this case, calcium carbonate, silica, zinc oxide, barium sulfate, clay, talc, inorganic fine powder of surface-treated calcium and silica, etc. are used as fillers, and lubricants such as higher fatty acids or esters, amides or metal salts thereof are used. , Various waxes, condensates of aromatic carboxylic acids and amino, phenyl benzoate and the like.

The amount of the constituent components of the overcoat layer ranges from 20 to 70% by weight for the binder, 5 to 50% by weight, preferably 10 to 30% by weight for the compound represented by the formula [I] of the present invention. Used.

The leuco dye used in the present invention is applied alone or as a mixture of two or more types. As such a leuco dye, those applied to this type of thermosensitive recording material,
For example, leuco compounds of dyes such as triphenylmethane, fluoran, phenothiazine, auramine, spiropyran and indolinophthalide are preferably used. Specific examples of such leuco dyes include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (also known as crystal violet lactone), 3,3-bis (p-dimethyl Aminophenyl) -6-diethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide, 3,3-bis (p-dibutylaminophenyl) phthalide, 3-cyclohexylamino-6-chlorofurf Oran, 3-dimethylamino-5,7-dimethylfluoran, 3- (N, N-diethylamino) -5-methyl-7-
(N, N-dibenzylamino) fluoran, benzoylleucomethylene blue, 6'-chloro-8'-methoxy-benzoindolino-
Pyrrolispirane, 6'-bromo-3'-methoxy-benzoindolino-
Pyrirospiran, 3- (2'-hydroxy-4'-dimethylaminophenyl) -3- (2'-methoxy-5'-chlorophenyl) phthalide, 3- (2'-hydroxy-4'-dimethylaminophenyl)- 3- (2'-methoxy-5'-nitrophenyl) phthalide, 3- (2'-hydroxy-4'-diethylaminophenyl) -3- (2'-methoxy-5'-methylphenyl) phthalide, 3- ( 2'-methoxy-4'-dimethylaminophenyl) -3- (2'-hydroxy-4'-chloro-5'-
Methylphenyl) phthalide, 3-morpholino-7- (N-propyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7-trifluoromethylanilinofluoran, 3-diethylamino-5-chloro-7- (N -Benzyl-trifluoromethylanilino) fluoran, 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluoran, 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluoran, 3 -(N-ethyl-p-toluidino) -7- (α-phenylethylamino) fluoran, 3-diethylamino-7- (o-methoxycarbonylphenylamino) fluoran, 3-diethylamino-5-methyl-7- (α -Phenylethylamino) fluoran, 3-diethylamino-7-peridino Ruoran, 2-chloro-3-(N-Mechirutoruijino) -7-
(Pn-butylanilino) fluoran, 3- (N-methyl-N-isopropylamino) -6
Methyl-7-anilinofluorane, 3-dibutylamino-6-methyl-7-anilinofluoran, 3,6-bis (dimethylamino) fluorenespiro (9,
3 ')-6'-dimethylaminophthalide, 3- (N-benzyl-N-cyclohexylamino)-
5,6-benzo-7-α-naphthylamino-4′-bromofluoran, 3-diethylamino-6-chloro-7-anilinofluoran, 3-N-ethyl-N- (2-ethoxypropyl) amino -6-ethyl-7-anilinefluoran, 3-siethylamino-7-chlorofluoran, 3-diethylamino-7-methylfluoran, 3-diethylamino-7,8-benzfluoran, 3-diethylamino-6 Methyl-7-chlorofluorane, 3- (Np-tolyl-N-ethylamine) -6-methyl-7-anilinofluoran, 3-pyrrolidino-6-methyl-7-anilinofluoran, 2- {N- (3'-trifluoromethylphenyl) amino} -6-diethylaminofluoran, 2- {3,6-bis (diethylamino) -9- (o-chloroanilino Xanthyl lactam benzoate, 3-diethylamino-6-methyl-7- (m-trichloromethylanilino) fluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino ) Fluoran, 3-N-methyl-N-amylamino-6-methyl-7
-Anilinofluoran, 3-N-methyl-N-cyclohexylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-N-ethyl-N -Tetrahydrofurfurylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-mesitidino-
4 ', 5'-benzofluoran and the like.

3-N-methyl-N-isobutyl-6-methyl-7-
Anilinofluoran, 3-N-ethyl-N-isoamyl-6-methyl-7-
Anilinofluoran, 3-diethylamino-6-methyl-7- (2 ', 4'-
Dimethylanilino) fluorane, and 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, may be used as a developer, if necessary. These can be used in combination, and specific examples are shown below.

4,4'-isopropylidenebisphenol, 4,4'-isopropylidenebis (o-methylphenol), 4,4'-secondary-butylidenebisphenol, 4,4'-isopropylidenebis (2-tert-butylphenol) 4,4'-cyclohexylidenediphenol, 4,4'-isopropylidenebis (2-chlorophenol), 2,2'-methylenebis (4-methyl-6-tert-butylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 4,4'-butylidenebis (6-tertbutyl-2-methyl) phenol, 1,1,3-tris (2-methyl-4-hydroxy-5-t
ert-butylphenyl) butane, 1,1,3-tris (2-methyl-4-hydroxy-5-
(Hydroxy-5-cyclohexylphenyl) butane, 4,4'-thiobis (6-tertbutyl-2-methyl) phenol, 4,4'-diphenolsulfone, 4-isopropoxy-4'-hydroxydiphenylsulfone, 4- Benzyloxy-4'-hydroxydiphenylsulfone, 4,4'-diphenolsulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechuate, stearyl gallate, lauryl gallate, octyl gallate, 1, 7-bis (4-hydroxyphenylthio) -3,5-dioxaheptane, 1,5-bis (4-hydroxyphenylthio) -3-oxapentane, 1,3-bis (4-hydroxyphenylthio)- Propane, 1,3-bis (4-hydroxyphenylthio) -2-hydroxypropane N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicylanilide, 5-chloro-salicylanilide, 2-hydroxy-3-naphthoic acid, 2-hydroxy-1-naphthoic acid Acid, 1-hydroxy-2-naphthoic acid, metal salts of hydroxynaphthoic acid such as zinc, aluminum and calcium.

Bis- (4-hydroxyphenyl) acetic acid methyl ester, bis- (4-hydroxyphenyl) acetic acid benzyl ester, 1,3-bis (4-hydroxycumyl) benzene, 1,4-bis- (4-hydroxycumyl) ) Benzene, 2,4'-diphenol sulfone, 3,3'-diallyl-4,4'-diphenol sulfone, antipyrine of zinc α, α-bis- (4-hydroxyphenyl) -α-methyltoluenethiocyanate Complex, tetrabromobisphenol A, tetrabromobisphenol S, 3,4-dihydroxy-4'-methyldiphenylsulfone, In the present invention, the leuco dye, the developer and the auxiliary component are bonded and supported on a support. In addition, various conventional binders can be appropriately used, for example, polyvinyl alcohol, starch and its derivatives, methoxy Cellulose derivatives such as cellulose, hydroxyethylcellulose, carboxymethylcellulose, methylcellulose, ethylcellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylic ester copolymer, acrylamide / acrylic ester / methacrylic acid terpolymer Styrene / maleic anhydride copolymer alkali salt, isobutylene / maleic anhydride copolymer alkali salt, water-soluble polymers such as polyacrylamide, sodium alginate, gelatin, casein, polyvinyl acetate, polyurethane, styrene / butadiene Copolymer, polyacrylic acid, polyacrylate, vinyl chloride / vinyl acetate copolymer, polybutyl methacrylate,
Latexes such as an ethylene / vinyl acetate copolymer and a styrene / butadiene / acrylic copolymer can be used.

In the present invention, together with the leuco dye, the developer and the auxiliary components, if necessary, auxiliary auxiliary components commonly used in this type of heat-sensitive recording material, for example, fillers, surfactants,
A heat-fusible substance (or lubricant) or the like can be used in combination.
In this case, as the filler, for example, other than inorganic fine powder such as calcium carbonate, silica, zinc oxide, titanium oxide, aluminum hydroxide, zinc hydroxide, barium sulfate, clay, talc, surface-treated calcium and silica, etc. , Urea-
Examples include organic fine powders such as formalin resin, styrene / methacrylic acid copolymer, and polystyrene resin.

[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 [Solution A] 3- (N-methyl-N-cyclohexylamino)-
6-methyl-7-anilinofluorane 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts [Solution B] 2,2'-bis (4-hydroxyphenyl) propane 2
0 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts [C liquid] Bisphenol S diacrylate 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts [D liquid] Bisphenol A diacrylate 20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts [Solution E] bis (4-glycidyloxyphenyl) sulfide
20 parts Polyvinyl alcohol 10% aqueous solution 20 parts Water 60 parts The mixture having the above composition was pulverized and dispersed by a sand grinder for 2 to 4 hours to prepare Liquid A and Liquid B. Moreover A solution, the weight ratio of the liquid B is 1: 3 to become so mixed and stirred and then dried coating weight on high quality paper of about 47 g / m ² weight commercial basis to prepare a thermal color-forming layer coating solution is 4.5 g / It was applied and dried to obtain m ² .

[C solution] 20 parts 10% polyvinyl alcohol aqueous solution 30 parts Calcium carbonate 3 parts 30% zinc stearate dispersion 3 parts Water 60 parts
The heat-sensitive recording material of the present invention was obtained by coating the heat-sensitive color-forming layer at 1.0 g / m ² and drying and calendering with a super calender so that the smoothness was 500 to 1000 seconds.

Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that [Liquid C] was used instead of [Liquid C].

Example 3 A heat-sensitive recording material was prepared in the same manner as in Example 1, except that [Solution E] was used instead of [Solution C].

Comparative Example 1 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that the solution C was removed from the overcoat liquid of Example 1.

Each thermal recording material obtained as described above was printed with Ricoh's thermal facsimile RIFAX130, and the sticking and scum sticking material was checked.A print test was performed 10,000 times with the same facsimile, and a Kosaka Laboratory surface roughness meter was used. The wear state of the head was measured.

 The results are shown below.

Comparative Examples 2 and 3 Glycerol polyglycidyl ether (Comparative Example 2) used for the overcoat layer in Examples 1 and 2 of JP-A-60-68990 and diphenylmethane-bis-
The heat-sensitive recording materials of Comparative Examples 2 and 3 were obtained in the same manner as in Example 1 of the present invention except that 4,4'-N, N'-diethyleneurea was used in place of biphenol S diacrylate (Comparative Example 3). Was. This was evaluated in the same manner as in Example 1. Table 2 shows the results.

[Effects] The heat-sensitive recording material of the present invention has no sticking and no sticking trouble, and has excellent head matching with very little influence on the head life.

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohisa Kakuda 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-60-68990 (JP, A) JP-A-62-270382 (JP, A) JP-A-49-36343 (JP, A) JP-A-62-263086 (JP, A) JP-A-62-259080 (JP, A)

Claims (1)

(57) [Claims] 1. A heat-sensitive recording material comprising a support and a heat-sensitive recording layer containing a leuco dye and a color developer, and an overcoat layer provided on the heat-sensitive recording layer. ] A heat-sensitive recording material comprising a compound represented by the formula: (Where R ₁ and R ₂ are each _{H 2 C = CH-CH 2} -, X is SO ₂ , Is shown. However, when X is SO ₂ , R ₁ and R ₂ are Except in the case of