JP2533788B2 - Thermal recording material - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material having excellent surface slipperiness and runnability when used by a facsimile.

(Prior Art) A recording material using an electron-donating dye precursor (hereinafter referred to as a color former) and an electron-accepting compound (hereinafter referred to as a developer) is used as a pressure-sensitive recording paper, a heat-sensitive recording paper, or a light-sensitive pressure-sensitive recording. It is well known as paper and electrically conductive recording paper.

For example, British Patent No. 2140449, US Patent No. 4480052,
No. 4436920, Japanese Patent Publication No. 60-23922, Japanese Patent Laid-Open No. 57-179836.
No. 60-123556, No. 60-123557, etc.

The recording material must have (1) sufficient color density and color sensitivity, (2) no fog, (3) sufficient storage stability of the color body after color development, 4) The surface is slippery and easy to handle.
And (5) there is no problem in running performance in facsimile, but at present, there is no product that completely satisfies them.

In particular, in recent years, the range of use of the thermal recording paper has expanded, and in various usage forms, demands for handleability and running performance of actual machines have become high. In order to satisfy these various performances, the slipperiness is increased (that is, the friction coefficient of the recording paper needs to be lowered). (Object of the invention) The object of the present invention is to provide a low recording paper friction coefficient and handleability. To provide an excellent heat-sensitive recording material.

(Structure of the Invention) An object of the present invention is to provide a thermal recording material utilizing the reaction of an electron-donating dye precursor and an electron-accepting compound, wherein the surface energy of the composition of the uppermost layer of the thermal recording material is 45 erg /
Achieved with a thermal recording material that is less than or equal to cm ² .

In order to improve the slipperiness of conventional thermal recording materials,
The surface smoothness is given by a calendering process or the like. However, the slipperiness of the surface of an object is determined by the interaction with the surface to be slipped, and it is uncertain whether one object is slippery or the other object is slippery as well. Is. This also applies to the heat-sensitive recording material, it is necessary to consider what the other party is, and imparting smoothness does not necessarily lead to improvement in slipperiness. Considering the handling property and the running property in a facsimile in the requirements of the performance of the thermal recording material, the other surface is often a relatively flat metal surface such as the inner wall of the apparatus, a glass surface or a plastic surface. In such a case, reducing the energy required for peeling the interface between two objects is considered to be the most effective means for improving the slipperiness. As a result of various tests carried out based on this consideration, it was found that the slip property is remarkably improved by keeping the surface energy of the composition of the uppermost layer of the thermal recording material small, and the present invention was completed.

The uppermost layer here is a coating layer provided at the end of the layer structure of the heat-sensitive recording material. That is, the surface energy of the composition of the protective layer when the thermosensitive coloring layer / protective layer is provided on the support, and the surface energy of the composition of the thermosensitive coloring layer when the undercoat layer / thermosensitive coloring layer is provided on the support. Is 45erg /
By using a heat-sensitive recording material having a cm ² or less, a heat-sensitive recording material having no problem in handling and running property can be obtained.

The surface energy is required to be 45 erg / cm ² , but preferably 40 erg / cm ² or less, more preferably 3 erg / cm ^2.
It is less than 5 erg / cm ² .

Further, the heat-sensitive recording material of the present invention having the uppermost layer having a low surface energy can be imparted with good slipperiness by further improving its flatness. When a material with high surface energy is used, good flatness may adversely affect the slipperiness. To improve the flatness and contribute to the slipperiness by treating with a calender, etc. Must be 45 erg / m ² or less.

There are various ways to control the surface energy,
It is not particularly limited. For example, one method is to optimize the composition by changing the composition of a color former, a color developer, a pigment, a binder and the like. It can also be controlled by adding an appropriate amount of a hydrophobic compound such as a fluorine-based hydrophobic surfactant, oils, paraffins, fatty acids, waxes and the like.

The surface energy value in the present invention is obtained by scraping off the surface of the uppermost layer of the heat-sensitive recording material with a razor or the like and finishing the obtained powder into pellets by a pressure molding machine. It can be obtained by measuring the contact angle between water and methylene iodide in this pellet in an atmosphere of 23 ° C. and 65% RH. The obtained values are calculated by substituting each value into the formula (1).

In the case of water; γ _l = 72.2 erg / cm ² γ _l ^D = 22.1 erg / cm ² γ _l ^H = 50.1 erg / cm ^{2 In} the case of methylene iodide γ _l = 50.8 erg / cm ² γ _l ^D = 49.5 erg / cm ² γ _l ^H = 1.3 erg / cm ² (Substituting the value of the contact angle (cos θ) measured in equation (1) and the surface energy of each liquid in the case of water and methylene iodide above. The surface energy γs of the solid is obtained by solving the simultaneous equations obtained in step 1.) As the color former used in the present invention, triarylmethane compounds, diphenylmethane compounds, xanthene compounds, thiazine compounds, spiropyran compounds, etc. Is mentioned. Specific examples include those described in JP-A-55-227253. If some of these are disclosed, as triarylmethane compounds, 3,3
-Bis (p-dimethylaminophenyl) -6-dimethylaminophthalide, 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3- (1,3dimethylindole- 3-il)
Phthalide, 3- (p-dimethylaminophenyl)-
3- (2-methylindol-3-yl) phthalide, etc., and as diphenylmethane compounds,
4'-bis-dimethylaminobenzhydrin benzyl ether, N-halophenyl-leuco auramine, N-2,4,
5-trichlorophenyl leuco auramine and the like, and xanthene compounds include rhodamine-B-anilinolactam, rhodamine- (p-nitrino) lactam, and 2
-(Dibenzylamino) fluorane, 2-anilino-3-methyl-6-diethylaminofluorane, 2-anilino-3-methyl-6-dibutylaminofluorane,
2-anilino-3-methyl-6-N-ethyl-N-isoamylaminofluorane, 2-anilino-3-methyl-
6-N-methyl-N-cyclohexylaminofluorane, 2-anilino-3-chloro-6-diethylaminofluorane, 2-anilino-3-methyl-6-N-ethyl-N-isobutylaminofluorane, 2- Anilino-6
-Dibutylaminofluoran, 2-anilino-3-methyl-6-N-methyl-N-tetrahydrofurfurylaminofluoran, 2-anilino-3-methyl-6-piperidinoaminofluoran, 2- (o -Chloroanilino)-
There are 6-diethylaminofluorane, 2- (3,4-dichloroanilino) -6-diethylaminofluorane, and the like, and as thiazine-based compounds, there are benzoyl leuco methylene blue, p-nitrobenzyl leuco methylene blue, and the like, and spiro-based compounds. Is 3-methyl-spiro-dinaphthopyran, 3-ethyl-spiro-dinaphthopyran 3,3'-dichloro-spiro-dinaphthopyran, 3-benzylspiro-dinaphthopyran, 3-methyl-naphtho-
(3-Methoxy-benzo) -spiropyran, 3-propyl-spiro-dibenzopyran and the like.

Phenolic compounds, salicylic acid derivatives and polyvalent metal salts thereof are preferable as the color developer used in the present invention. To give an example of some of these, examples of the phenolic compound include 2,2′-bis (4-hydroxyphenyl) propane, 4-t-butylphenol, 4-phenylphenol, 4-hydroxydiphenoxide, and 1,1 ′. -Bis (3-
(Chloro-4-hydroxyphenyl) cyclohexane, 1,
1′-bis (4-hydroxyphenyl) cyclohexane,
1,1'-bis (3-chloro-4-hydroxyphenyl)-
2-ethylbutane, 4,4'-sec-isooctylidene diphenol, 4,4'-sec-butylidene diphenol, 4-t
Examples include ert-octylphenol, 4-p-methylphenylphenol, 4,4'-methylcyclohexylidenephenol, 4,4'-isopentylidenephenol, and benzyl p-hydroxybenzoate. Examples of salicylic acid derivatives include 4-pentadecylsalicylic acid, 3,5-di (α-methylbenzyl) salicylic acid, 3,5-di (ter-octyl) salicylic acid, 5-octadecylsalicylic acid, 5-α- (p-
α-methylbenzylphenyl) ethylsalicylic acid, 3-
α-methylbenzyl-5-ter-octylsalicylic acid,
5-tetradecylsalicylic acid, 4-hexyloxysalicylic acid, 4-cyclohexyloxysalicylic acid, 4-decyloxysalicylic acid, 4-dodecyloxysalicylic acid, 4-pentadecyloxysalicylic acid, 4-octadecyloxysalicylic acid, and the like, zinc and aluminum thereof. , Calcium, copper, lead salts. These color developers are preferably used in an amount of 50 to 800% by weight, more preferably 100 to 500% by weight of the color former. If the content is less than 50% by weight, the coloring is not sufficient, and if it is added more than 800% by weight, no further effect can be expected, which is not preferable.

In the heat-sensitive recording material of the present invention, a heat-fusible substance can be contained in the heat-sensitive coloring layer in order to improve the thermal response. Examples of preferred heat-fusible substances include benzyl p-benzyloxybenzoate, β-naphthyl-benzyl ether, stearamide, stearyl urea, p-benzyl biphenyl, di (2-methylphenoxy) ethane,
Di (2-methoxyphenoxy) ethane, β-naphthol- (p-methylbenzyl) ether, α-naphthylbenzyl ether, 1,4-butanediol-p-methylphenyl ether, 1,4-butanediol-p-isopropyl Phenyl ether, 1,4-butanediol-p-tert-
Octyl phenyl ether, 1-phenoxy-2- (4
-Ethylphenoxy) ethane, 1-phenoxy-2-
(4-chlorophenoxy) ethane, 1,4-butanediol phenyl ether, diethylene glycol-bis (4
-Methoxyphenyl) ether and the like. The heat-fusible substance is used alone or in combination, and in order to obtain a sufficient thermal response, it is necessary to
It is preferably used in an amount of 10 to 200% by weight, more preferably 20 to 150% by weight.

In the present invention, the color-developing agent, the color-developing agent and the heat-fusible substance are dispersed in a water-soluble binder. The binder used in the present invention is 5% by weight or more soluble in water at 25 ° C The compound is preferable, and specifically, polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, starches (including modified starch), gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolyzate, carboxy modified polyvinyl alcohol. , Polyacrylamide, saponified products of vinyl acetate-polyacrylic acid copolymer, and the like. These binders are used not only at the time of dispersion but also for the purpose of improving the coating strength. For this purpose, styrene-butadiene copolymer, vinyl acetate copolymer, acrylonitrile
It is also possible to use a latex binder of a synthetic polymer such as a butadiene copolymer, a methyl acrylate / butadiene copolymer, or polyvinylidene chloride.

If necessary, pigments, metal soaps, waxes, surfactants, antistatic agents, ultraviolet absorbers, defoamers, conductive agents, fluorescent paints, etc. may be added.

As the pigment, calcium carbonate, barium sulfate, lithopone, wax, kaolin, silica, amorphous silica and the like are used.

As the metal soap, higher fatty acid metal salts are used, such as zinc stearate, calcium stearate, and aluminum stearate.

As the wax, a paraffin wax, a microcrystalline wax, a carnauba wax, a methylol stearamide, a polyethylene wax, a polystyrene wax, a fatty acid amide wax or the like is used alone or in combination.

As the surfactant, a sulfosuccinic acid-based alkali metal salt and a fluorine-containing surfactant are used.

Further, it is preferable to add an anti-color erasing agent in the heat-sensitive color developing layer in order to prevent decoloring of the image printed portion and to make the generated image fast. As the anti-decoloring agent, a phenol compound, particularly a hindered phenol compound is effective, for example,
1,1,3-tris (2-methyl-4-hydroxy-tert-
Butylphenyl) butane, 1,1,3-tris (2-ethyl-4-hydroxy-5-tert-butylphenyl) butane, 1,1,3-tris (3,5-di-tert-butyl-4-) Hydroxyphenyl) butane, 1,13-tris (2-methyl-
4-hydroxy-5-tert-butylphenyl) propane, 2,2'-methylene-bis (6-tert-butyl-4-methylphenol), 2,2'-methylene-bis- (6-tert
-Butyl-4-ethylphenol), 4,4'-butylidene-bis (6-tert-butyl-3-methylphenol),
4,4'-thio-bis- (3-methyl-6-tert-butylphenol), and the like. The amount of such a phenolic compound used is preferably 1 to 200% by weight, more preferably 5 to 50% by weight, based on the color developer.

Each of these materials is mixed and then applied to the support. As the support, paper, synthetic paper, various bases and the like are used, but an undercoat may be preliminarily applied on the support in order to obtain high smoothness.

The applied heat-sensitive recording material is dried and subjected to treatment with a calendar or the like before use.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to the examples.

For the running performance, a high speed facsimile FF-2000 of Fujitsu Ltd. was used and a copy of the IEICE Test Chart No. 3 was copied.
The following criteria evaluated the accumulating property and sticking of the printing sample.

Slip property by slide-type friction coefficient measuring instrument placed stainless of the pressurizer so that a load of 10 g / m ^2, the angle start slippage pressurizer was measured and the coefficient of static friction with tan .theta.

(Aggregability) Good: Accumulation was good when 100 sheets were accumulated.

△: Out of 100 sheets, 5 sheets or less did not stack well.

×: Out of 100 sheets, 6 or more sheets were not stacked well.

(Sticking) ○: No sticking is observed.

Δ: White and white highlights (portions that are not printed due to stick slips) occur at 2 to 3 places, but print shrinkage does not occur.

X: There are many overexposed areas and the print is shrunk.

[Examples and Comparative Examples]

The total of 20 g of electron-donating dye precursors shown in Table 1 is 100 g
5% aqueous polyvinyl alcohol solution and 2 g of the basic organic compound shown in Table 1 were dispersed in a ball mill for 24 to 48 hours to obtain a dispersion having a particle size as shown in Table 1. Further, 20 g of the electron-accepting compound shown in Table 1 was dispersed together with 100 g of a 5% aqueous solution of polyvinyl alcohol in a ball mill for 24 to 48 hours to obtain a dispersion having a particle size as shown in Table 1.

Also, 80 g of the pigment shown in Table 1 is added to 0.5 g of sodium hexametaphosphate.
% Aqueous solution (160 g) to obtain a pigment dispersion.

The dispersions obtained as described above were mixed in the proportions shown in Table 1, and further mixed with 21% zinc stearate emulsion and 30%.
% Paraffin wax emulsion and other compounds shown in Table 1 were added to obtain a coating solution for thermal paper, and a wire was applied to a fine paper having a basis weight of 50 g / m ^{2 so} that the dry coating amount was 7 g / m ^2. It was coated with a bar and dried in an oven at 50 ° C. to obtain a heat-sensitive recording material of the present invention.

As shown in Table 2, it was found that the heat-sensitive recording material according to the present invention has a low coefficient of friction and has good running properties.

Claims (1)

(57) [Claims] 1. A heat-sensitive recording material utilizing the reaction of an electron-donating dye precursor and an electron-accepting compound, wherein the surface energy of the composition of the uppermost layer of the heat-sensitive recording material is 45 erg / cm ² or less. Heat sensitive recording material