JP3163966B2 - Winding thermal recording sheet - Google Patents

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 sheet, and more particularly to a roll-up heat-sensitive recording sheet whose support is made of synthetic paper or a synthetic resin film. And a rolled-up thermal recording sheet.

[0002]

2. Description of the Related Art In recent years, the use of thermosensitive recording papers in printers, facsimile machines, recorders for various analytical instruments, and the like has been particularly frequently used by being incorporated in the above-mentioned apparatus in a wound form. I have. Depending on the state of the case and the device, the remaining state of the winding is often difficult to identify, so that the remaining state of the thermosensitive recording paper can be visually checked during the use process. End mark for identification near the end (colored ink)
Is widely performed.

[0003] In the case of a thermosensitive recording paper whose support is made of synthetic paper or a synthetic resin film (hereinafter simply referred to as a synthetic paper), that is, a thermosensitive recording paper made of synthetic paper, a thermosensitive recording layer and a protective layer. Also, an end mark is provided as in the case where the support is paper. In this case, the colored ink for the end mark adheres to the paper surface, but has difficulty in adhesion and fixation, and falls off when rubbed with a finger, and prints the colored portion of the ink of the end mark by a thermal recording method. Then, the ink residue adheres to the thermal head,
In some cases, recording failure due to sticking (insufficient device suitability) and the like occurred.

In the case of an aqueous colored dye, drying after adhering to recording paper or the like is poor, workability during processing is poor, and a pigment-based dye is difficult to obtain a uniform color, and sticking and the like are difficult. It has the drawback that it is easy to occur.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned drawbacks of the conventional colored ink used for the end mark of the thermal recording paper (sheet), has a stable fixing property, and Provided is a rolled-up thermal recording sheet coated with colored ink for end marks which does not fall off.

[0006]

According to the present invention, a heat-sensitive recording layer containing a basic dye and a color developing agent as main components and a colored ink on a specific portion thereof are attached to one surface of a synthetic paper or a synthetic resin film. In a rolled thermal recording sheet having a laminated protective layer, an ink containing alcohol, an azo dye soluble in alcohol, and a rosin- modified resin or / and ketone resin as an adhesive is used as the colored ink. Which is a rolled thermal recording sheet.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As described above, the present invention relates to a rolled-up thermal recording sheet having an end mark (colored ink) at least at the end thereof. Conventionally,
Normally, an end mark of the thermal recording sheet, that is, an end mark for announcing the end of the recording sheet is printed near the end of winding. In the case of winding, for example, in the case of winding, the end mark is marked with colored ink using a felt pen or the like over a portion several m from the end of winding. Needless to say, a mark with a specific color is also provided as an index for indicating the remaining length or the number of sheets even during winding or the like.
As described above, conventional colored inks have various difficulties.

For example, conventionally used end mark inks include aqueous inks and solvent-based inks in which dyes and adhesives are dissolved in various solvents. The water-based ink was not practical because it dried poorly, had blocking and set-off, and could only be operated at an extremely low speed when used. On the other hand, in a solvent-based ink, for example, a solvent ink using ethyl alcohol as a solvent,
When the ink is applied, a normal thermal paper dissolves the coloring component, so that it mixes with the color of the ink and a clear color cannot be obtained. In the case of a solvent ink containing toluene or the like as a main component, a phenol resin is used as an adhesive from the viewpoint of solubility. However, sticking tends to occur during thermal recording, which is not preferable from an environmental point of view. Further, in order to suppress color development, there is a solvent in which normal paraffin, isoparaffin, or the like is used as a solvent, but the solubility is poor, and a clear and dense end mark cannot be obtained. As described above, there are various restrictions on the use of the conventional ink for end marks in terms of handling and environmental aspects.

In the present invention, an ink in which at least an azo dye, a rosin-modified resin and / or a ketone resin is dissolved in an alcohol is used as a colored ink for an end mark, which is used particularly for a thermosensitive recording paper having a synthetic paper as a support. It is characterized by doing. By using the ink having such a configuration, the adhesion between the ink and the heat-sensitive recording paper (protective layer) is improved, and sticking or the like does not occur. It has been found that it can be used, and the present invention has been completed.

As described above, the rolled thermal recording sheet with end marks according to the present invention is characterized by colored ink used for end marks. That is, the colored azo dye does not change its hue due to the aqueous binder or pigment contained in the protective layer and has excellent stability over time. Further, discoloration or the like does not occur on the back surface of the synthetic paper that comes into direct contact with the winding finish.

In particular, an alcoholic ink containing an azo dye is a colored solution due to alcohol (s) used as a solvent. When this ink solution is applied to the protective layer of a heat-sensitive recording sheet, Alcohol, which is a solvent, swells the aqueous binder in the protective layer to increase the adhesiveness and to penetrate into the recording layer provided thereunder. However, the fact is that alcohol evaporates and evaporates during such a process, and as a result, most of the alcohol evaporates and escapes before the alcohol passes through the protective layer and reaches the recording layer below. Alcohol has almost no effect on the dye or developer in the heat-sensitive recording layer. Further, since the drying proceeds rapidly, the subsequent processability is also good.

Further, as a solvent for a conventional solvent-based coloring ink, an ink dissolved in an organic solvent such as toluene is often used, but such a solvent has environmental problems, and furthermore, an alcohol is difficult. In particular, when compared with ethyl alcohol, the rate of vaporization and evaporation is considerably slow, and there is a difficulty in handling. Therefore, it is a preferable embodiment to use alcohol which can be used from the viewpoint of handling and environment, particularly ethyl alcohol.

When a color ink dissolved in alcohol is used as an end mark ink in a heat-sensitive sheet comprising a support made of synthetic paper and a heat-sensitive recording layer and a protective layer provided thereon, the recording layer is colored. The reason why no alcohol is induced is that the alcoholic colored ink adhered to the protective layer takes time to swell the aqueous binder and the like in the protective layer, during which vaporization and evaporation proceeds, and the alcohol passes through the protective layer to reach the recording layer. As a result, the fixing of the dye to the protective layer and the drying (evaporation of the alcohol) proceed rapidly. By the way, when the support is ordinary base paper, even if a protective layer is provided, the air permeability of the support is good, so that a part of the alcohol relatively easily passes through the protective layer to reach the heat-sensitive recording layer. And reached a color change.

Next, the azo dye, which is the main component of the ink for end marks, usually has a solid content of 1 to 5% by weight as an ink solution, though it depends on the cost, the color and the density of the end marks.
Used in the range. Examples of the alcohol used as a solvent for the azo dye include lower alcohols such as methyl alcohol, ethyl alcohol, and propyl alcohol. Among them, ethyl alcohol is preferably used from the viewpoint of safety and the like.

As the adhesive used together with the above-mentioned azo dye, a rosin-modified resin and / or a ketone resin are preferably used because of their good affinity with the aqueous binder in the protective layer. In particular, since the adhesion between the ink and the protective layer is improved and the plasticity due to heat is small, troubles such as sticking and adhesion of scum during thermal recording are unlikely to occur. Incidentally, a modified phenol resin, a hydrocarbon resin, a maleic acid resin, or the like is not preferable because it has a problem in terms of device characteristics.

The composition of the ink composition for a solvent (alcohol) end mark having the above composition is not particularly limited, but in order to obtain the desired effect of the present invention, for example, 100 parts by weight of alcohol is used. The azo dye is prepared in an amount of 2 to 10 parts by weight and the rosin-modified resin and / or ketone resin (as a total amount) serving as an adhesive in an amount of 1 to 10 parts by weight relative to the solid content. The concentration of the colored ink solution is not particularly limited, but is usually adjusted in the range of 5 to 15% by weight from the viewpoint of adhesion and device characteristics.

The azo dye is not particularly limited as long as it can be easily dissolved in lower alcohols. Among rosin-modified resins and ketone resins, those that show plasticity by heat induce sticking during heating recording, so that thermosetting resins are selected and used.
Incidentally, the azo dyes used in the present invention include, for example, stilbene azo dyes, metal complex salt azo dyes, thiazole azo dyes, and the like. Can be Examples of the ketone resin include an acetone-formaldehyde resin and an acetone-furfural resin.

The colored ink for end mark thus obtained is impregnated with a felt pen or a sponge on the protective layer surface of a thermosensitive recording sheet having a protective layer using synthetic paper as a support, or By transferring to a rubber roll or the like, recording is performed as an end mark.

The basic structure of the rolled heat-sensitive recording sheet according to the present invention is that a heat-sensitive recording layer containing a leuco dye and a coloring agent, and a protective layer containing an aqueous resin and a pigment are formed on a synthetic paper used as a support. This is a rolled thermosensitive recording sheet in which end marks made of colored ink are added on the protective layer. Here, as the leuco dye, various known leuco dyes can be used,
For example, 3- (4-diethylamino-2-ethoxyphenyl) -3- (1-ethyl-2-methylindole-3-
Yl) -4-azaphthalide, crystal violet lactone, 3- (N-ethyl-N-isopentyl) amino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7-anilinofluoran, 3-diethylamino-6-methyl-7- (o, p-dimethylanilino) fluoran, 3- (N-ethyl-Np-toluidino) -6-methyl-7-anilinofluoran, 3-
Pyrrolidino-6-methyl-7-anilinofluoran, 3
-Di (n-butyl) amino-6-methyl-7-anilinofluoran, 3- (N-cyclohexyl-N-methyl)
Amino-6-methyl-7-anilinofluoran, 3-diethylamino-7- (o-chloroanilino) fluoran, 3-dibutylamino-7- (o-chloroanilino)
Fluoran, 3-diethylamino-7- (m-trifluoromethylanilino) fluoran, 3-diethylamino-6-methyl-7-chlorofluoran, 3-diethylamino-6-methylfluoran, 3-cyclohexylamino-6 Chlorofluorane, 3- (N-ethyl-N-hexyl) amino-6-methyl-7- (p-chloroanilino) fluoran and the like can be mentioned. Two or more leuco dyes can be used.

Various compounds are also known as colorants used in combination with leuco dyes, for example, 4-cumylphenol, hydroquinone monobenzyl ether, 4,4
4′-isopropylidene diphenol, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4 ′
-Dihydroxydiphenyl-2,2-butane, 4,4 '
-Dihydroxydiphenyl sulfide, bis (4-hydroxy-3-methylphenyl) sulfide, 4,4'-
Dihydroxydiphenylsulfone, 2,4′-dihydroxydiphenylsulfone, 4-hydroxy-4′-methyldiphenylsulfone, 4-hydroxy-4′-isopropoxydiphenylsulfone, bis (3-allyl-4-
(Hydroxyphenyl) sulfone, 4-hydroxyphenyl-4′-benzyloxyphenylsulfone, 4-hydroxy-3 ′, 4′-tetramethylenebiphenylsulfone, 3,4-dihydroxyphenyl-p-tolylsulfone, 4-hydroxybenzoic acid Benzyl ester, N,
N'-di-m-chlorophenylthiourea, 4,4'-bis (p-tolylsulfonylaminocarbonylamino) diphenylmethane, 4- [2- (p-methoxyphenoxy) ethyloxy] salicylic acid, 4- {3- (p -Tolylsulfonyl) propyloxy] zinc salicylate, 5-
[P- (2-p-methoxyphenoxyethoxy) cumyl] zinc salicylate and the like. Of course, these colorants may be used in combination of two or more, if necessary.

In the present invention, the ratio of the leuco dye to the color former in the recording layer is appropriately selected depending on the type of the leuco dye and the color former used, and is not particularly limited. The acidic substance is used in an amount of 1 to 10 parts by weight, preferably 1 to 5 parts by weight, per 1 part by weight of the colorless or pale leuco dye.

To prepare a coating solution containing these substances, an aqueous solution in which a dispersant is dissolved is used as a dispersion medium, and a leuco dye and a color former are mixed together with a ball mill, an attritor, a sand mill or the like, or a pulverizer. Separately with an average particle size of 2
It is dispersed in a particle size of 1 μm or less, preferably 1 μm or less, and is prepared as a coating liquid.

In such a coating solution, starch, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, gelatin, casein, gum arabic, polyvinyl alcohol, styrene / maleic anhydride copolymer alkali salt, ethylene / acrylic acid are usually used as binders. Copolymer alkali salt, styrene / acrylic acid copolymer alkali salt, natural rubber emulsion, styrene / butadiene copolymer emulsion, acrylonitrile / butadiene copolymer emulsion, methyl methacrylate / butadiene copolymer emulsion, polychloroprene Emulsions, vinyl acetate emulsions, ethylene / vinyl acetate emulsions and the like are added in an amount of about 5 to 20% by weight of the total solids of the recording layer.

If necessary, various additives may be used in combination, for example, lubricants such as zinc stearate, calcium stearate, polyethylene wax, carnauba wax, paraffin wax and ester wax; calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide , Silicon dioxide, aluminum hydroxide, barium sulfate, talc,
Inorganic pigments such as kaolin, clay, calcined clay and colloidal silica; organic pigments such as styrene microballs, nylon powder, polyethylene powder, urea / formalin resin filler; stearamide, N-methylstearic amide, benzalinide, methylene stearate Fatty acid amides such as bisamides;

4,4'-butylidenebis (6-tert-butyl-3-methylphenol), 2,2'-methylenebis (4-ethyl-6-tert-butylphenol),
4-di-tert-butyl-3-methylphenol, 1,
1,3-tris (2-methyl-4-hydroxy-5-te
rt-butylphenyl) butane, 1,1,3-tris (5
-Cyclohexyl-4-hydroxy-2-methylphenyl) butane, 1,3,5-tris (5-tert-butyl-
Hindered phenols such as 3-hydroxy-2,6-dimethylbenzyl) isocyanuric acid; 4- (2-methyl-1,2-epoxyethyl) diphenylsulfone;
Diphenylsulfone derivatives such as-(2-ethyl-1,2-epoxyethyl) diphenylsulfone, 4-benzyloxy-4 '-(2,3-glycidyloxy) diphenylsulfone; 2- (2'-hydroxy-5' -Methylphenyl) benzotriazole, 2-hydroxy-
UV absorbers such as 4-benzyloxybenzophenone;
1,2-di (3-methylphenoxy) ethane, 1,2-
Diphenoxyethane, parabenzylbiphenyl, naphthylbenzyl ether, benzyl-4-methylthiophenyl ether, 1-hydroxy-2-naphthoic acid phenyl ester, oxalic acid dibenzyl ester, oxalic acid-di-p-methylbenzyl ester, oxalic acid And thermal sensitivity improvers (sensitizers) such as -di-p-chlorobenzyl ester, dibutyl terephthalate, dibenzyl terephthalate and dibutyl isophthalate.

The average particle diameter of the above additives contained in the heat-sensitive recording layer is preferably 2 μm or less. The amount of the additive used is not particularly limited. For example, the amount of the sensitizer used is generally 4 to 1 part by weight of the colorant.
It is desirable to adjust the amount within the range of not more than part by weight.

Further, it is necessary to provide a protective layer containing an aqueous resin and a pigment on the heat-sensitive recording layer for the purpose of, for example, smearing stains and improving print storability. Examples of the pigment include inorganic pigments such as calcium carbonate, zinc oxide, aluminum oxide, titanium dioxide, silicon dioxide, aluminum hydroxide, barium sulfate, zinc sulfate, talc, kaolin, clay, calcined kaolin, calcined clay, colloidal silica, and styrene. Organic pigments such as microballs, nylon powder, polyethylene powder, urea / formalin resin filler, raw starch particles, and the like can be used, and two or more of these can be used in combination. Among these pigments, titanium dioxide or silicon dioxide having a high concealing property, or an organic pigment is preferably used. These are used in an amount of 20 to 80% by weight based on the solid content in the protective layer coating solution.

As the aqueous resin, polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, silicon-modified polyvinyl alcohol, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose, starch and derivatives thereof, casein, sodium alginate, polyvinylpyrrolidone, Water-soluble resins such as polyacrylamide, styrene / maleic acid copolymer salt, polyurethane resin, urea resin, melamine resin, polyamide resin; styrene / acrylate emulsion, styrene / butadiene emulsion, acrylate emulsion, etc. Examples thereof include a water-dispersible resin, and it is also possible to use two or more of these. These are used in an amount of 20 to 80% by weight based on the solid content of the protective layer coating solution.

Further, zinc stearate, calcium stearate, and the like may be contained in the coating solution for forming the protective layer, if necessary.
Lubricants such as polyethylene wax, carnauba wax, paraffin wax, and ester wax, direct dyes, ultraviolet absorbers, microcapsules containing ultraviolet absorbers, and various other auxiliaries can also be appropriately added.

The thus-prepared coating solution for the heat-sensitive recording layer and the coating solution for the protective layer are sequentially applied onto the above-mentioned undercoat layer according to a conventionally known and commonly used technique, and dried to form a heat-sensitive recording layer and a protective layer. Examples of the coating device include an air knife coater, a rod blade coater, a pure blade coater, a short dwell coater, a curtain coater, and a bar coater. The coating solid content of the heat-sensitive recording layer is 1 to 25 g / m ² , preferably 3 g / m ² .
To 15 g / m ² , and the coating solid amount of the protective layer is 1 to
20 g / m ^2, preferably it is desirable to adjust the range of 2 to 10 g / m ^2.

By providing a resin layer on the protective layer and / or on the back surface of the heat-sensitive recording sheet as required, it is possible to further improve the preservability of the heat-sensitive recording image. In addition, various known techniques in the field of heat-sensitive recording material manufacturing can be applied by applying an adhesive to the back surface and processing it into an adhesive label, or providing a magnetic layer. Of course, after forming the undercoat layer, the heat-sensitive recording layer, and the protective layer, a super calender treatment can be performed to improve the image quality and the image density.

In the present invention, examples of the synthetic paper serving as a support include PET films and PP films, and specific examples thereof include Yupo (Oji Yuka) and peach coat (Toyobo). The thickness of the synthetic paper actually used is not particularly limited, and usually, a thickness of about 60 to 100 μm is preferably used.

[0033]

The present invention will be specifically described below with reference to examples. Of course, the present invention is not limited to these. Unless otherwise specified, “%” and “part” in the examples indicate “% by weight” and “part by weight”, respectively.

Example 1 [Preparation of solution A] 3- (N-ethyl-N-iso-amylamino) -6-methyl-7-phenylamino fluoran 15 parts Dibenzyl terephthalate 30 parts 5% aqueous solution of methyl cellulose 20 parts Water 40 Part The above composition was pulverized by a sand mill until the average particle diameter became 3 μm.

[Preparation of Liquid B] 4,4′-isopropylidenediphenol 25 parts 5% aqueous solution of methylcellulose 40 parts Water 20 parts The above composition was pulverized by a sand mill until the average particle diameter became 3 μm.

[Formation of Recording Layer] 90 parts of solution A, 90 parts of solution B
Parts, 30 parts of silicon oxide pigment, 1 part of polyvinyl alcohol
300 parts of a 0% aqueous solution and 28 parts of water were mixed and stirred to obtain a coating liquid. The coating liquid thus obtained was applied on a 50 μm-thick polyethylene terephthalate film (PET) having been subjected to a corona discharge treatment on both sides by a dry weight of 5 g / m ^2.
Was applied and dried to form a recording layer.

[Formation of Protective Layer] Water 30 parts 60% aqueous dispersion of kaolin 10 parts 30% aqueous dispersion of zinc stearate 3 parts 10% aqueous solution of polyvinyl alcohol 30 parts The above compositions were mixed and stirred. The obtained coating liquid was coated on the above-mentioned recording layer so as to have a dry weight of 2 g / m ^2, and dried to form a protective layer, thereby obtaining a raw material of thermal paper.

The raw material obtained in this manner was set on a slitter to form a small winding of 30 m. Separately, an ink for an end mark composed of 8 parts of an azo dye (red), 4 parts of a rosin-modified resin, and 100 parts of ethyl alcohol was prepared. Marking was put. When the winding was loosened and the end mark portion was checked, it did not come off even when rubbed with a finger and showed good fixability. No set-off was seen. Furthermore, when recording on the end mark part with a thermal head, sticking did not occur,
Normal recording was completed.

Example 2 A small thermal paper was prepared in the same manner as in Example 1 except that the rosin-modified resin was replaced with a ketone resin in the ink composition for end marks to prepare the ink for end marks. Winding was performed, an end mark was formed on the thermal paper using the ink, and fixing properties and the like were checked in the same manner as in Example 1. As a result, the same results as in Example 1 were obtained.

Comparative Example 1 In Example 1, an ink having a composition consisting of 5 parts of a monoazo dye, 4 parts of a phenol resin, 50 parts of toluene and 50 parts of hexane was used in place of the ink for end marks used in Example 1. A small heat-sensitive roll was prepared in the same manner as in Example 1 except that the fixing was performed with the end mark ink. As a result, when the end mark portion was rubbed by hand, the mark was easily removed and the fixation was poor. Also, when recording was performed on the ink portion with a thermal head, sticking occurred, and satisfactory recording was not possible.

[0041]

As is evident from the results of Examples 1 and 2, the rolled thermal recording sheet finished with the ink for end marks according to the present invention exhibits excellent fixability and generates sticking. And normal recording was possible.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M 5/28-5/34 C09D 11/00

Claims (2)

(57) [Claims] 1. One side of synthetic paper or synthetic resin film,
In a rolled thermosensitive recording sheet having a thermosensitive recording layer containing a basic dye and a color developer as main components, and a protective layer in which a colored ink is adhered to a specific portion of the roll, the alcohol is used as the colored ink. A roll-up heat-sensitive recording sheet comprising an ink containing a azo dye that dissolves and a rosin- modified resin and / or a ketone resin as an adhesive. 2. The rolled thermal recording sheet according to claim 1, wherein the alcohol is selected from at least one of methyl alcohol, ethyl alcohol and propyl alcohol.