JP3129491B2 - Thermal recording medium - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention relates to heat-sensitive recording material that utilizes the color forming reaction between a leuco dye and a developer on a support, have a under layer particularly excellent in color uniformity, Bradenton
The present invention relates to a thermosensitive recording material manufactured by a spin coating method .

[0002]

2. Description of the Related Art In various recording apparatuses using thermal recording paper, there is a strong demand for higher sensitivity of thermal recording paper as the size, cost and speed of the recording apparatus increase. It is also desirable to improve productivity in order to reduce the cost of thermosensitive recording paper. Engineering is used as the center. Various proposals have been made to increase the sensitivity. Among them, it has been proposed that a plastic-based non-foamed hollow body is effective to impart heat insulation to the under layer. Among them, in order to exert the effect particularly, it is important to use a plastic latex having the same thermal conductivity as the binder.

[0003] However, Japanese Patent Application Laid-Open No.
4-14075, JP-A-1-285383, 2-214
When a thermal layer is formed by a blade coating method using a hollow body and a latex resin-based underlayer as disclosed in JP-A No. 688, etc., a unique color formation pattern of scale spots occurs, and the color formation density is poor, and the color formation density is partially low. And the drawback of having no function as a recording paper occurs.

Japanese Patent Application Laid-Open No. 2-204686 discloses a proposal for improving streaks and scratches by a blade coating method, which is characterized by lowering the water absorption coefficient Ka. the at a under-layer system tends to reduce the color formation. Also, generally speaking
When the contact angle with water exceeds 60 degrees even when the absorption coefficient Ka is between 0.4 and 0.25, a new defect that the thermal layer forming liquid does not adhere in a pinhole shape occurs. This
There is .

Japanese Patent Application Laid-Open No. 61-154991 proposes to use a water-resistant resin having good wettability with water for an under layer. There is a disadvantage that background fogging is caused by residual layers. In addition, since a water-resistant resin layer is formed, the absorption coefficient Ka as an under layer decreases, and when the thermal liquid is applied by blade coating, the thermal liquid does not reach the immobilization point and the liquid stagnates. There is a disadvantage that unevenness occurs and color uniformity is extremely poor.

[0006]

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, and an object of the present invention is to provide a method for coating a support having a heat-insulating underlayer using a plastic non-foamed hollow body by a blade coating method. High sensitivity and excellent color uniformity in thermal recording media with laminated thermal layer
Certain to be subjected Hisage.

[0007]

According to the present invention , there is provided a thermosensitive recording medium comprising:
Using latex resin and plastic non-foamed hollow body
A thermal recording medium comprising a substrate having an under layer and a thermal layer laminated by a blade coating method , wherein the under layer further comprises a water-soluble resin in an amount of 5% based on the total resin solid content.
Absorption coefficient Ka based on the Bristow method (J. TAPPI paper pulp test method No. 51-87)
There characterized in that the contact angle with it and water at 0.25ml / m ² · msec ^1/2 or more is less than 60 degrees, further
Of water-soluble resin used as under layer forming resin
The amount is 5% to 30% based on the total resin solids.
On the other hand, latex resin and plastic non-foaming
On a substrate having an underlayer using a hollow body, a blade is provided.
Thermal recording media with a thermal layer laminated by a coating method.
And the under layer further comprises a 2-propenoic acid homopoly
Sodium salt and 2,5-furandion and 2,4
Sodium salt of a copolymer with 4-trimethylpentene,
Butanedioic acid sulfo 1,4-bis (2-ethylhexyl)
Polycarboxylic acids selected from ester sodium salts
It contains a lukali salt and is prepared using the Bristow method (J. TAPPI Paper
Rup Test Method No. 51-87) Water absorption
Is the number Ka 0.25 ml / m ² · msec ^1/2 or more?
The contact angle with water is 60 degrees or less.

The under layer according to the present invention can be formed by dry-coating a plastic-based non-foamed hollow body and a resin together with a resin on a support. In this case, the particle diameter of the plastic non-foamed hollow body is desirably 10 μm or less. Further, this plastic non-foamed hollow body can be used in combination with various fillers used for conventional general paper. Examples of such a filler include calcium carbonate, kaolin, talc, zinc oxide, aluminum hydroxide, silica, magnesium silicate, poly-sterene resin, and urea formaldehyde resin. When used in combination with such a filler, the mixing ratio is not particularly limited, but generally the filler is used at a ratio of 0.1 to 1 part by weight with respect to 1 part by weight of the plastic non-foamed hollow body. Is done.

The resin used for the under layer is S
It is desirable to add a water-soluble resin of 5% or more to the total resin solid content to latex resin such as BR latex,
Particularly, 5% to 30% is preferable. The total solid content of the resin used in the under layer is 5% of the total solid content of the under layer.
% To 40% is preferred. As the water-soluble resin added to the under layer resin, polyvinyl alcohol, modified polyvinyl alcohol, methyl cellulose, and hydroxyethyl cellulose are desirable. If the amount of such a water-soluble resin is less than 5% of the total resin, the effect of changing the absorption coefficient Ka and the contact angle is insufficient, and if it exceeds 30%, the effect is saturated, And it is economically disadvantageous.

On the other hand, the resin used for the under layer is S
When only a latex resin such as BR latex is used, it is desirable to use an alkali polycarboxylate as an additive (surfactant) in or on the under layer. The amount of addition is not particularly limited, but is preferably 0.05% to 5% based on the total solid content of the under layer.
If the addition amount is less than 0.05%, the effect of changing the absorption coefficient Ka and the contact angle is insufficient, and if it exceeds 5%, the effect is saturated and is economically disadvantageous. The polycarboxylic acid alkali salt, 2 - propenoic acid homopolymer sodium salt and 2, 5-furandione and 2,4,4
Sodium salt of a copolymer with trimethylpentene and sulfo-1,4-bis (2-ethylhexyl) butanedioate
Ester sodium salts are preferred.

Further, an organic filler may be added to the under layer according to the present invention, if necessary. Examples of the organic filler include a phenol derivative having a coloring ability, paraffin, and an amide wax.

The blade coating in the present invention is not limited to a coating method using a bevel type or vent type blade, but includes a coating method using a roll blade or the like, a bill blade coating method, and the like. Also, in dwell time, you are not restricted to long and short. In addition, the blade coating is not limited to the off-machine, but may be performed using an on-machine coater installed on a paper machine.

Next, the material for forming a thermal layer used in the present invention will be described. The leuco dyes used in the present invention may be used alone or as a mixture of two or more kinds. As such leuco dyes, those applied to this type of recording material are arbitrarily applied. Methanephthalide, triallylmethane, fluoran, phenothiazine, thiofluoran, xanthene, indophthalyl, spiropyran, azaphthalide, chromenopyrazole, methine, rhodamine anilinolactam, rhodamine lactam, quinazoline Compounds, diazaxanthene compounds, bislactone compounds and the like are preferably used. Examples of such compounds include, for example, those shown below.

3,3-bis (p-dimethylaminophenyl) -phthalide, 3,3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide 3,3-bis (p-dimethylaminophenyl)- 6-diethylaminophthalide 3,3-bis (p-dimethylaminophenyl) -6-chlorophthalide 3,3-bis (p-dibutylaminophenyl) phthalide 3-cyclohexylamino-6-chlorofluoran 3-dimethylamino-5 , 7-Dimethylfluoran 3- (N-methyl-N-isoamylamino) -6-methyl-7-anilinofluoran 3- (N-methyl-N-isobutylamino) -6-methyl-7-anilino Fluoran 3- (Np-tolyl-N-ethylamino) -6-methyl-7-anilinofluoran 3- (N-methyl-N- Amylamino) -6-methyl-
7-anilinofluoran 3- (N-methyl-N-cyclohexylamino) 6-methyl-7-anilinofluoran 3- (N-methyl-N-iso-propylamino) -6
-Methyl-7-anilinofluoran 3- (N-ethyl-N-tetrahydrofurfurylamino) -6-methyl-7-anilinofluoran 3-diethylamino-7,8-benzfluoran 3-diethylamino-7 -Chlorofluorane 3-diethylamino-7-methylfluoran 3-diethylamino-6-methyl-7-chlorofluorane 3-pyrrolidino-6-methyl-7-anilinofluoran 3-diethylamino-6-methyl-7- (M-trichloroanilino) fluoran 3-diethylamino-7- (o-chloroanilino) fluoran 3-dibutylamino-7- (o-chloroanilino) fluoran 3-diethylamino-6-methyl-7-anilinofluoran 3-dibutyl Amino-6-methyl-7-anilinofluoran 3-diethylamino- - methyl-7- (2 ', 4'-
Dimethylanilino) fluoran 3- (N, N-diethylamino) -5-methyl-7-
(N, N-dibenzylamino) fluoran benzoyl leucomethylene blue 6'-chloro-8'-methoxybenzoindolinospiropyran 6'-bromo-8'-methoxybenzoindolinospiropyran 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-propyltrifluoromethylanilino) fluoran 3-pyrrolidino-7-trifluoromethylanilinofluoran 3-diethylamino-5-chloro-7- (N-benzyl-tri Fluoromethylanilino) fluoran 3-pyrrolidino-7- (di-p-chlorophenyl) methylaminofluoran 3-diethylamino-5-chloro-7- (α-phenylethylamino) fluoran 3- (N-ethyl-N- p-Toluidino) -7- (α-
Phenylethylamino) fluoran 3-diethylamino-7- (o-methoxycarbonylphenylethyl) fluoran 3-diethylamino-5-methyl-7- (α-phenylethylamino) fluoran 3-diethylamino-7-piperidinoaminofluoran 2-chloro-3- (N-methyltoluidino) -7- (p
-N-butylanilino) fluorane 3,6-bis (dimethylamino) fluorenespiro (9,3 ')-6'-dimethylaminophthalide 3- (N-ethyl-N-cyclohexylamino) -5,
6-benzo-7-α-naphthylamino-4′-bromofluorane 3-diethylamino-6-chloro-7-anilinofluoran 3- (N-ethyl-N-2-ethoxypropylamino)
-6-methyl-7-anilinofluoran 3- (N-ethyl-tetrafurfurylamino) -6-methyl-7-anilinofluoran 3-diethylamino-6-methyl-7-mesitidino-
4 ', 5'-benzofluoran 3- (p-dimethylaminophenyl) -3- {1,1-
Bis (p-dimethylaminophenyl) ethylene-2-yl {phthalide 3- (p-dimethylaminophenyl) -3- {1,1-
Bis (p-dimethylaminophenyl) ethylene-2-yl {-6-dimethylaminophthalide 3- (p-dimethylaminophenyl) -3- (1-p-
Dimethylaminophenyl-1-phenylethylene-2-
Yl) phthalide 3- (p-dimethylaminophenyl) -3- (1-p-
Dimethylaminophenyl-1-p-chlorophenylethylene-2-yl) -6-dimethylaminophthalide 3- (4′-dimethylamino-2′-methoxy) -3-
(1 "-p-dimethylaminophenyl-1" -p-chlorophenyl-1 ", 3" -butadiene-4 "-yl) benzophthalide 3- (4'-dimethylamino-2'-benzyloxy)
-3- (1 "-p-dimethylaminophenyl-1" -phenyl-1 ", 3" -butadiene-4 "-yl) benzophthalide 3-dimethylamino-6-dimethylamino-fluorene-9-spiro-3 '(6'-dimethylamino) phthalide 3,3-bis {2- (p-dimethylaminophenyl)-
2- (p-methoxyphenyl) ethenyl} -4,5,
6,7-tetrachlorophthalide 3-bis {1,1-bis (4-pyrrolidinophenyl) ethylene-2-yl} -5,6-dichloro-4,7-dibromophthalide bis (p-dimethylamino Styryl) -1-naphthalenesulfonylmethane bis (p-dimethylaminostyryl) -1-p-tolylsulfonylmethane and the like.

In the present invention, various electron-accepting compounds such as phenolic compounds are used as a developer.
Thiophenolic compounds, thiourea derivatives, organic acids and metal salts thereof can be used, and specific examples thereof include, but are not limited to, those shown below.

4,4'-isopropylidene diphenol, 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′-dihydroxyphenyl) 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-methyl-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'-diphenol sulfone, 4-isopropoxy-4'- Hydroxydiphenylsulfone, 4-benzyloxy-4′-hydroxydiphenylsulfone, 4,4′-diphenolsulfoxide, isopropyl p-hydroxybenzoate, benzyl p-hydroxybenzoate, benzyl protocatechulate,
Stearyl gallate, lauryl gallate, octyl gallate, 1,3-bis (4-hydroxyphenylthio) propane, N, N'-diphenylthiourea, N, N'-di (m-chlorophenyl) thiourea, salicyl Anilide,
Methyl bis- (4-hydroxyphenyl) acetate, benzyl bis (4-hydroxyphenyl) acetate, 1,3-bis (4-hydroxyphenyl) benzene, 1,4-bis (4-hydroxyphenyl) benzene, 2,4 '-Diphenol sulfone, 2,2'-diallyl-4,4'-hydroxyphenyl sulfone, 3,4-dihydroxy-
4'-methyldiphenyl sulfone, zinc 1-acetyloxy-2-naphthoate, zinc 2-acetyloxy-3-naphthoate, zinc 2-acetyloxy-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 color 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 ethyl cellulose, sodium polyacrylate, polyvinylpyrrolidone, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer, styrene /
Alkaline salt of maleic anhydride copolymer, alkali salt of isobutylene / maleic anhydride copolymer, water-soluble polymers such as polyacrylamide, sodium alginate, gelatin and casein, as well as polyvinyl acetate, polyurethane, polyacrylate and polyacrylate Emulsions such as methacrylates, vinyl chloride / vinyl acetate copolymers, ethylene / vinyl acetate copolymers, and latexes such as styrene / butadiene / acrylic copolymers.

In the present invention, various heat-fusible substances can be used in combination as a sensitivity enhancer, 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, zinc stearate, aluminum stearate;
Fatty acid metal salts such as calcium stearate, zinc palmitate, and zinc behenate, p-benzylbiphenyl, terphenyl, triphenylmethane, benzyl p-benzyloxybenzoate, β-benzyloxynaphthalene, β
Phenyl naphthoate, 1-hydroxy-2-phenyl naphthoate, methyl 1-hydroxy-2-naphthoate,
Diphenyl carbonate, gliacol carbonate, dibensil 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.

In the present invention, various conventional fillers can be used in an appropriate amount. Specific examples thereof include calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silica, aluminum hydroxide and zinc hydroxide. , Barium sulfate,
In addition to clay, talc, inorganic fine powder of surface-treated calcium carbonate and silica, urea-formalin resin can be used. As other additives, lubricants such as zinc stearate and calcium stearate, various surfactants, and antifoaming agents are added as required.

Examples of the support include paper, synthetic paper, film and the like. In addition, a protective layer can be provided if necessary, and surface treatment can be performed using a super calendar or the like.

[0023]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, of course, are not intended to limit the scope of the present invention. Parts and% in Examples are parts by weight and% by weight unless otherwise specified.

Example 1 A mixture having the following composition was stirred and dispersed with a disper to prepare an underlayer forming liquid [liquid A]. [A solution] styrene / hollow acrylic copolymer (solid content 37%) 60 parts (hollow ratio 30% to 35%, outer particle diameter 0.4 to 0.5 [mu] m) scan switch Ren / butadiene copolymer (solid 50%) 10 parts Itaconic acid-modified polyvinyl alcohol aqueous solution (solid content 5%) 15 parts Water 15 parts Also, a mixture having the following composition is pulverized and dispersed by a sand grinder so that the average particle diameter becomes 1-2 μm. [B
Liquid] [liquid C]. [Solution B] 3-Dibutylamino-6methyl-7anilinofluoran 30 parts Silicon oxide pigment 10 parts 10% polyvinyl alcohol aqueous solution 20 parts Water 40 parts [Solution C] Bisphenol A 10 parts Dibenzyl oxalate 10 parts Hydroxide Aluminum 20 parts Sulfone-modified polyvinyl alcohol aqueous solution (solid content 10%) 20 parts Water 40 parts Subsequently, the mixture was stirred and mixed at a weight ratio of [liquid B]: [liquid C] = 1: 6 to prepare a thermal layer forming liquid. . Next, [Liquid A] is applied to a commercially available high-quality paper having a basis weight of 50 g / m ^{2 by} a blade coating method so as to have a dry adhesion amount of 5 g / m ^2, and then dried. the amount 4g / m ² and composed so coated and dried at a blade coating method to give direct thermal recording material of the performed present invention to a surface treatment by further supercalender.

Example 2 Example 1 Itaconic acid-modified polyvinyl alcohol in [solution A]
Except for changing the Lumpur solution (5% solids) in aqueous solution of methyl cellulose (5% solids) was obtained direct thermal recording material of the present invention in the same manner as in Example 1.

Example 3 Example 1 Itaconic acid-modified polyvinyl alcohol in [solution A]
Except for changing the Lumpur solution (5% solids) to hydroxyaldehyde cellulose (5% solids) was obtained direct thermal recording material of the present invention in the same manner as in Example 1.

Example 4 [Solution D] Hollow body of styrene / acrylic copolymer (solid content 37%) 60 parts (hollow ratio 30-35%, particle outer diameter 0.4-0.5 μm) methylene / butadiene copolymer Polymer (solid content: 50%) 10 parts 2-propenoic acid homopolymer sodium salt 0.1 part Water 29.9 parts Example 1 Same as Example 1 except that [Solution A] was changed to [Solution D]. to obtain a sensitive thermal recording material of the present invention Te.

Example 5 Example 4 The sodium salt of 2-propenoic acid homopolymer in [Solution D] was changed to the sodium salt of a copolymer of 2,5-furandione and 2,4,4-trimethylpentene. except to obtain direct thermal recording material of the present invention in the same manner as in example 1.

Example 6 Example 4 Example 1 was repeated except that the sodium salt of 2-propenoic acid homopolymer in [solution D] was changed to sodium salt of butanediacid sulfo-1,4-bis (2-ethylhexyl) ester. to obtain a sensitive thermal recording material of the present invention in a similar manner.

Comparative Example 1 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the aqueous solution of itaconic acid-modified polyvinyl alcohol in [Liquid A] was not used.

Comparative Example 2 A heat-sensitive recording material was prepared in the same manner as in Example 1 except that 15 parts of the aqueous solution of itaconic acid-modified polyvinyl alcohol in [Liquid A] was changed to 0.75 parts of ethyl cellulose and 14.25 parts of toluene. I got

Comparative Example 3 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that the itaconic acid-modified polyvinyl alcohol in [Liquid A] was changed to a styrene / maleic sizing agent.

Comparative Example 4 A heat-sensitive recording material was obtained in the same manner as in Example 1 except that 15 parts of ethylene glycol (5% aqueous solution) was added to [Liquid A].

<Evaluation> (1) The support provided with the undercoat layer was subjected to the Bristow method (J. TAPPI paper pulp test method No. 51).
-87), the absorption coefficient for water was measured. (2) With respect to the support provided with the undercoat layer, the contact angle was measured with 4 μl of the dropping solution using an automatic contact angle meter CA-Z manufactured by Kyowa Interface Science Co., Ltd. (3) Printing characteristics: Thermal printing power applied by Matsushita Electronic Components Co., Ltd. Thermal printing head: 0.68 w / dot / 1 line Recording time: 5 msec / l, scanning line density: 8 × 7.7 dots / mm 0.25 msec width and 0.
Printing was performed at 3 msec, and the image density and background density at that time were measured using Macbeth density system RD-914. In addition, the evaluation of good to bad was also performed for uniform color development of the printed image.

[0035]

[Table 1]

[0036]

As is apparent from the above description, according to the present invention, when a thermal layer is laminated on a support having a heat-insulating underlayer using a plastic-based non-foamed hollow body by a blade coating method, and Turkey can provide a thermosensitive recording material excellent in color uniformity with high sensitivity was confirmed.

────────────────────────────────────────────────── ─── Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/28-5/34

Claims (3)

(57) [Claims] 1. A latex resin and plastic type non-elastomer
Heat-sensitive recording material der formed by laminating a thermal layer by a blade coating method on a substrate having an under layer using a foam hollow body
Thus, the under layer further fixes the water-soluble resin to the entire resin.
5% or more based on the form fraction, and the Bristow method (J. TAP)
PI paper pulp test method No. 51-87) A heat-sensitive recording material characterized by having an absorption coefficient Ka for water of 0.25 ml / m ² · msec ^1/2 or more and a contact angle with water of 60 degrees or less . 2. The heat-sensitive recording medium according to claim 1, wherein the amount of the water-soluble resin used as the resin for forming the under layer is 5% to 30% based on the total resin solid content . 3. A latex resin and plastic type non-elastomer
Blade on substrate with underlayer using foam hollow body
This is a thermal recording medium with a thermal layer laminated by a coating method.
Thus, the under layer further comprises a 2-propenoic acid homopolymer.
Rimmer sodium salt and 2,5-furandion and 2,
Sodium copolymer with 4,4-trimethylpentene
Salt, butanedioic acid sulfo 1,4-bis (2-ethylhexyl
G) Polycarboxylic acid selected from ester sodium salt
Containing acid-acid alkali salts and the Bristow method (J. TAPPI
Paper pulp test method No. 51-87)
The yield coefficient Ka is 0.25 ml / m ² · msec ^1/2 or more
And the contact angle with water is not more than 60 degrees.
Thermosensitive recording medium.