JPS63209992A - heat sensitive recording material - Google Patents

Abstract

PURPOSE:To enhance preservability such as water resistance, oil resistance or the like, by providing a thermal color forming layer containing a specific color forming dye and a sulfonyldiphenol compound on a support. CONSTITUTION:A coating solution consisting of a color forming dye being 2,2-bis{4-[6'-(N-cyclohexyl-N-methylamino)-3'-methylspiro[phthalide-3, 9'-xanthen]- 2'-ylamino]phenyl}propane represented by formula I and a sulfonyldiphenol compound represented by formula II (wherein R1 and R2 an arbitrary substituent, and m and n are an integer of 0-4) and formula III (wherein R3 and R4 are H or OH and R5 is H, halogen or a lower alkyl group) is prepared and applied to a support such as paper or a plastic film to form a thermal recording mate rial having a thermal color forming layer.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a fishing coloring agent consisting of (1) a normally colorless or slightly pale colored dye, and an organic acid or phenolic substance that causes the colored dye to develop color when heated; and.

The present invention relates to a heat-sensitive recording material having a heat-sensitive coloring layer containing a binder.

More specifically, this heat-sensitive recording material is long-lasting.

In particular, the water resistance of the paint film (1) the water resistance of the colored part, and the discoloration that occurs when it comes into close contact with a plastic film containing a large amount of plasticizer (
The present invention relates to a heat-sensitive recording material with improved plasticizer resistance and discoloration that occurs when oil such as meat or edible oil is attached (hereinafter referred to as oil resistance).

(Prior Art) Conventionally, various heat-sensitive recording sheets are known in which a paint obtained by dispersing a lactone compound such as crystal violet lactone and a phenol compound such as bisphenol A in a binder such as a polyvinyl alcohol solution and coating a support on a support ( For example, see Japanese Patent Publication No. 45-14039).

When this type of heat-sensitive recording sheet is heated, a color-forming lactone compound and an organic acid or a phenol compound chemically react to develop color. In this case, the basic properties required of the heat-sensitive record sheet are that it has good color development, is as white as possible in appearance, has the appearance of natural paper, and has long shelf life. °C,
(a) High sensitivity, (b) No sticking (sticking) → Good compatibility with the thermal head is required, including no dregs adhering to the thermal head.7 -1゜As described above, heat-sensitive recording materials are desired to have Permanent properties depending on their use, but these dye-type color-forming materials are sensitive to light, water, temperature, plasticizers, oil, etc. On the other hand, because it is unstable at °C, changes over time during storage are always a problem. Therefore, when using such a recording sheet and printing desired characters on it,

The recorded color develops extremely clearly, but if a plastic film containing a large amount of plasticizer (for example, a soft vinyl chloride film) is placed tightly on the coloring area, or if it is stored with oil or fat attached, There was a drawback that the adhesive part would fade. Also, when the colored part is in contact with water for a long period of time, a remarkable blue color often appears.

These discolorations are particularly noticeable in color-forming type heat-sensitive recording materials that use dyes mainly composed of colorless or light-colored lactone compounds (they occur when the heat-sensitive recording material comes into contact with oil or plasticizers). Assuming that it is a common problem of i'i, the solution to it has traditionally been strong < 18! R'C.

In order to improve the storage stability of conventional heat-sensitive recording materials, it has been proposed to provide an overcoat layer made of a water-soluble polymer compound on the heat-sensitive coloring layer. Because it interferes with heat sensitivity, heat sensitivity worsens.

Since a coating process for the overcoat layer was required, there was a drawback that the height was increased by two strokes. Furthermore, in thermal labels and thermal tickets manufactured by cutting and adhesive processing such thermal recording materials coated with such an overcoat layer, oil and other substances may penetrate through the cut surface and cause decoloration of the temperature printed area. Therefore, application of such an overcoat layer is not an essential solution.

The present invention aims to solve the problem (p) and provide a heat-sensitive recording material having improved water resistance, plasticizer resistance, and oil resistance and long-term storage stability.

For example, it can be used not only as a thermosensitive ticket for automatic ticket vending machines, but also for coupon tickets and commuter passes that require shelf life, and for POS barcode pricing, as well as for perishable foods and oils. We are developing heat-sensitive recording materials that are not only suitable for binding applications such as label paper that is attached to the packaging surface when meat is packaged with polyvinyl chloride film, but also can be used as facsimile paper and printer paper for long-term storage. This is what we provide.

(Means for Solving the Problems) The present inventors have developed a thermosensitive recording layer having a thermosensitive coloring layer containing a usually colorless or light-colored coloring dye and a color developer that develops color at °C upon contact with the coloring agent. 2,2-bis(4-C6'-(N-cyclohexyl-N-methylamino)-5'-methylspiro[7talide 3,9 '-xanthine)-2'-ylaminocophenyl)propane is used as a color-forming dye, and # is used as a color developer. 1m and n
is an integer from 0 to 4. , ) or R, R5 (wherein R3 and R1 represent a hydrogen atom or a hydroxyl group.

However, R3 and R do not represent a hydrogen atom at the same time. Moreover, R5 is a hydrogen atom or a halogen atom.

Indicates a lower alkyl group, alkoxyl group, aryloxyl group or benzyloxy group. A heat-sensitive recording material using a combination of at least one compound selected from the sulfonyl diphenol compounds represented by ) and stearyl gallate.

As mentioned above, it satisfies the basic properties required for a heat-sensitive recording sheet, and also has water resistance, plasticizer resistance, and oil resistance.

It has been found that a heat-sensitive recording material with significantly improved storage stability such as light resistance can be obtained.

By employing a combination of special compounds such as those mentioned above as color-forming dyes and color developers, there is no need to provide an overcoat layer containing a water-soluble polymer compound as a main component on the heat-sensitive color-forming layer. It is possible to appropriately prevent discoloration when it comes into close contact with a soft film or when it is exposed to oil or fat, and exhibits excellent stability and storage stability.

The materials used in the heat-sensitive recording material of the present invention will be explained in detail below.

As the color-forming dye, 2,2-bis(4-(6'-(N-cyclohexyl-N-methylamine)-3'-methylspiro[7thalido-3,9'-xanthine]) having the formula (1) above is used. -2'-ylamino]phenyl)propane is used alone or in combination of two or more.

Such mixed leuco dyes and temperatures used in this kind of heat-sensitive materials can be optionally used.

6-diethylamino-6-methyl-anilinofluorane, 3-pyrrolidino-6-methyl-7-anilinofluorane, 3-pyridino-6-methyl-7-anilinofluorane, 3-(N- Methyl-N-cyclohexylamino)-6-methyl-7-anilinofluorane, 6-dinithylamino-7-chloroanilinofluorane, 3-(N
-ethyl-N-(p-methylphenyl)amine2-6-
Fluoran series such as methys-fuanilinofluorane, 6-dinithylamino-7-(methtrifluoromethyl)anilinofluorane,! 1.3-bis-(p-dimethylaminophenyl)-6-dimethylanophthalide (crystal violet lactone), 3.3-bis-(p-
dibutylamino7enyl)phthalide, 3,6-bis-(
p-dimethylaminophenyl) phthalide, triphenylmethane series such as 4-hydroxy-47-dimethylaminotriphenylmethane lactone, 3-methyl-diβ-su7tospialane, 1,3.3-)rifthyl-6 Spirolane dyes such as '-chloro8'-methoxyindolinobenzospirolane, and leuco dyes such as auramine, rhodamine lactam, and phenothiazine dyes are also used. However, the invention is not limited to these representative examples.

In the present invention, it is used as one of the color developers.

The sulfonyl diphenol compound represented by the general formula (1) or (1) is 1°C, for example, 4,4'-dihydroxydiphenylsulfone, 2,4'-dihydroxydiphenylsulfone, 6,6'-dihydroxydiphenylsulfone, 3 .6'-diamino-4,47-dihydroxy-
Diphenylsulfone, 3.3'-t7 Mi7 44/
-dihydroquine diphenyl sulfone, 3.3'-171
Flu 4. a'-v Hydroxydiphenyl sulfone.

3.3'-cyclo*ro 4.4'-dihydroxydiphenylsulfone, 4-hydroxy-diphenylsulfone 4-
human axy-4'-isoglobil diphenyl sulfone,
4-Hydroxy-4'-isoglobyloxydiphenylsulfone, 4-hydroxy-47,<fuzyloxydiphenylsulfone, 2.4-0hydroxy-diphenylsulfone, 2.4-dihydroxy-4/-methyl:) phenyl sulfone, s,4-dihydroxyphenyl-p-)
Examples include, but are not limited to, risulfone. This color developer contains 1 to 5 parts of leuco dye.
Weight part.

Preferably 1.5 to 6 parts by weight of 7) I is used.

In the present invention, stearyl gallate is used as a color developer in combination with the above sulfonyl diphenol compound. Stearyl gallate has a ratio of 0.1 to leuco dye
It is used in a proportion of 2''N parts, preferably 0.2 to 1.5 parts by weight.

Sulfonyl diphenol compounds have a relatively high shelf life1
When used with a color-forming dye of formula (1).

Shows excellent oil resistance and plasticizer resistance. However, since these have high melting points and are abundant, they have problems in color development and compatibility with thermal heads. The present inventors have conducted intensive research to make it possible to apply this sulfonyldiphenol compound to high-sensitivity heat-sensitive recording materials while taking advantage of its excellent high storage stability. The present invention was completed based on the discovery that the color density can be increased by changing the usage. The heat-sensitive recording material of the present invention has less background fog compared to the case where a sulfonyl diphenol compound is used alone.

It has excellent storage stability, good recording suitability, and high sensitivity.

As the binder for the heat-sensitive coloring layer, known binders can be used at all degrees Celsius. However, it is preferable that the liquid does not develop color, aggregate, or become highly viscous when mixed with the dispersion liquid of the color-forming dye and the color-developing substance, and the heat-sensitive recording sheet The formed film b'' is required to be strong, non-thermosensitive, and suitable for J: chemical sticking.

The associated aqueous binders include polyvinyl alcohol, modified starch, gum arabic, gelatin, methylcellulose, human 90xethylcellulose, carboxymethylcellulose, and polyvinylpyrrolidone.

Polyacrylate, polyacrylamide, styrene
Emulsions of maleic anhydride copolymer, styrene-butadiene latex, acrylic acid Nisder copolymer, etc. can be used.

In order to impart water resistance to the coating film, a combination of a water-soluble polymeric substance containing a reactive group such as an acetoacetyl group, a carboxyl group, an amide group, etc. and a curing agent is desirable. As the curing agent, glyoxal, glyoxal, #? In addition to dialdehyde systems such as Rialdehyde 9, polyamine systems such as polyethyleneimine, epoxy polyamide resins, diglycidyl systems such as glycy7rin diglycidyl ether, :) methylolflare, etc., ammonium persulfate, ferric chloride, magnesium chloride, etc. Known compounds such as metal salts and ammonium chloride are used.

In addition to this, for the MMJ coloring layer, if necessary.

An auxiliary additive component commonly used in this type of heat-sensitive recording material.

For example, saline, surfactant, thermofusible substance (or lubricant)
There is no problem in using these together. in this case.

As a filler, 7"C is 1. For example, calcium carbonate, magnesium carbonate, kaolin, clay, Merck, calcined clay, silica, diatomaceous earth 1. Synthetic aluminum silicate, synthetic silica magnesium, zinc oxide, titanium dichloride, hydroxide. In addition to inorganic fine powders such as thereminium, barium sulfate, surface-treated fl, calcium carbonate, and silica, mention organic fine powders such as urea-formalin resin, styrene/methacrylic acid combined, and polystyrene resin. For example, stearic acid amide, stearic acid ethylene bisamide, 9. oleic acid amide, fatty acid amide such as lumitylic acid amide, coconut fatty acid amide, behenic acid amide, stearic acid. Zinc, calcium stearate, polyethylene wax, carnauba wax, paraffin wax, waxes such as ester wax, terephthalic dimethyl ester, terephthalic acid.
) butyl ester.

Terephthalic acid shifthyl ester, isophthalic acid shifthyl ester, 1-hydroxynaphthoic acid phenyl ester, 1.2-y<3-methylphenol)ethane,
1.2-diphenoxyethane, 1-phenoxy-2-(
4-methylphenoxy)ethane.

carbonic acid fig, p-benzylbiphenyl, 2.
2'-methylenebis(4-methyl-6-t--7'tylphenol), 4,4'-butylidenebis(6-t-butyl-6-methylphenol), 1,1.3-)lis(
2-Methyl-4-hydroxy-5-t-butylphenylbutane, 2,2'-methylenebis(4-ethyl-6-
t-butylphenol), 2,4-di-t-butyl-3
- Methylphenol, hiftatephenols such as 4,4'-thiobis(6-methyl-6-t-butylphenol), and 2-(2'-hydroxy-5'-methylphenyl)benzotriazole.

Various heat-fusible substances such as 2-hydroxy-4-benzyloxybenzophenone, lubricants, antioxidants, and ultraviolet inhibitors are added.7:J0 Regarding the amount of heat-fusible substances added, C. is not particularly limited, and is generally preferably in the range of about 4 parts by weight or less per 1 part by weight of the color developer.

C is the support used in the heat-sensitive recording material of the present invention.

Papers such as grain paper, medium quality paper, art paper, coated paper, cast coated paper, paperboard, tissue paper, etc. are generally used, but plastic films, synthetic paper, laminated paper, aluminum foil, etc. can also be used.

(Example) The present invention will be described in more detail below using Examples, but is not limited thereto. Parts in each example indicate parts by weight.

Example 1 (1) Preparation of liquid A 2.2-bis(4-(6'-<N-cyclohexyl-
N-methylamine)-6'-methylspiro[phtari]"
-3,9'-xanthine-2'-ylamino]phenyl)furopane 6 parts 10% polyvinyl alcohol aqueous solution 6 parts water
10 parts (2) Solution B preparation a, 25 parts of 4'-v hydroxydiphenyl sulfone 7 parts of stearyl gallate 32 parts of 10% polyvinyl alcohol aqueous solution
36 parts of the sealing liquid and liquid B were ground and dispersed on each side using a sand mill to an average particle size of 6 μm or less.

(3) Formation of thermosensitive coloring layer 50 parts of 60% calcium carbonate aqueous dispersion, 25 parts of liquid A, 1.10% as binder (allyl acetoacetate-acrylamide-PVA copolymer 1 ratio/315 ) 200 copies,
75 parts of solution B, 17 parts of 30% zinc stearate dispersion, 6
10 parts of 0% paraffin wax, 60% 1.1.3-
) Lis(2-methyl-4-hydroxy-5-tert-
10 parts of a butane dispersion, 75 parts of a 60% diphenyl taurate dispersion, and 3 parts of a 30% polyaldehyde solution were mixed to prepare a coating solution. After coating this coating liquid on the base paper of 501/A so that the dry weight becomes 6y-/-,
Perform super calendar processing to smooth Beck! 300-3
A heat-sensitive coloring layer was provided for 50 seconds.

Example 2 A heat-sensitive recording material was obtained by carrying out the operation under the same conditions as in Example 1, except that the following liquid C was used instead of liquids 1'C and B in Example 1.

(1) 2,4'-v hydroxydiphenyl sulfone manufactured by O Liquid 25M stearyl gallate 7 parts 10% polyvinyl alcohol aqueous ff 32M water
36 parts Example 3 A heat-sensitive material was obtained by carrying out the operation under the same conditions as in Example 1, except that the following liquid B was used instead of liquids 1'C and B in Example 1.

(1) Preparation of liquid D, 4-y hydroxyphenyl-p-trisulfone
25 parts Erosion stearyl acid 7 parts 10% polyvinyl alcohol aqueous solution 62 parts Water
66 parts Example 4 A thermosensitive recording material was obtained by carrying out the operation under the same conditions as in Example 1, except that the following liquid E was used in place of liquid B in Example I.

+11 E liquid preparation 4-human 90x-47-methyldiphenyl sulfone
25 parts eroded stearyl acid 7 parts 10% polyvinyl alcohol water 81 32 g (S water
66 parts Comparative Example 1 A heat-sensitive recording material was obtained by carrying out the operation under the same conditions as in Example 1, except that the following liquid E was used instead of liquid B in Example I.

(11F liquid preparation 4,4'-dihydroxydiphenylsulfone 62 parts 10
%yk': +) Vinyl alcohol aqueous solution 62
Department water
66 parts Comparative Example 2 A thermosensitive recording material was obtained by carrying out the operation under the same conditions as in Example 1, except that the following G liquid was used instead of Birc in Example 1.

(1) G liquid preparation bisphenol A 32 parts 10
% polyvinyl alcohol aqueous solution 62 parts water
66 parts Comparative Example 6 A heat-sensitive recording material was obtained under the same conditions as in Example 1, except that the following liquid H was used in place of liquid B in Example 1.

+11) Benzyl p-hydroxybenzoate 62 parts 10% polyvinyl alcohol aqueous solution 62 parts water
66 parts Comparative Example 4 A heat-sensitive recording material was obtained under the same conditions as in Example 1 except that Liquid I was used instead of Liquid A in Example 1.

(1) Preparation of working solution 3-diethylamino-6-methyl-7-anilinofluorane 6 parts 10% 4+7 vinyl alcohol aqueous solution 6 parts water
10 parts Comparative Example 5 Example 6 except that liquid I was used instead of liquid A in Example B.
The operation was carried out under the same conditions as above to obtain a heat-sensitive recording material.

Each of the heat-sensitive recording materials of Examples and Comparative Examples shown in 3 was heated at room temperature.
After being left for a day, each was printed solidly using a printer equipped with a thin film line head at a head power of 0.7 W K'''c, and the aptitude for marking and color density were measured. Reflection densitometer (RD-514)
The recording suitability was evaluated by sticking (sticking to the head). Next, predetermined test pieces were prepared from this material by a conventional method, and the water resistance, film resistance, and oil resistance of one colored portion were measured by the following tests. The results are shown in the table. As is clear from this table, satisfactory results were obtained in each of the Examples, but in each Comparative Example, appropriate results were not obtained in some properties.

+11 Water resistance test: After soaking the test piece in water for 24 hours (at room temperature), take it out and keep it g! Evaluation is based on the Ijj elution state and the residual S degree after drying.

(2) PVC film resistance test: A soft polyvinyl chloride film was superimposed on the specimen.

24 under a load of 1300 P/cnr2 at 20°C
Evaluation is made based on each residual concentration when the two are brought into contact for a period of time.

(3) Oil resistance test: Apply cottonseed oil to a test piece using a woven method, and evaluate based on each residual quality after standing at 20°C for 24 hours. As is clear from the table, in Examples 1 to 5 IC, Compared to Comparative Examples 1 to 4, water resistance, PVC film resistance,
Excellent results were also obtained in terms of oil resistance.

(Effects of the Invention) The heat-sensitive recording material of the present invention is capable of exhibiting excellent water resistance, plasticizer resistance, and oil resistance without providing any overcoat layer made of a water-soluble multimolecular compound or the like. As a result, it can be used for a wider range of applications, such as single-use commuter passes, label paper, or printer paper, which especially require essential long-term shelf life. This has the effect of expanding the possibilities of use.

Claims (1)

[Claims] 1. In a heat-sensitive recording material having a heat-sensitive coloring layer containing a color-forming dye and a color developer, the color-forming dye is represented by the formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) 2,2-bis{4-[6'-(N-cyclohexyl-N-methylamino)-3'-methylspiro[
Using phthalide-3,9'-xanthene]-2'-ylamino]phenyl}propane and as a color developer, there are formulas ▲mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R_1 and R_2 are Any substituent, m and n are integers from 0 to 4) and formulas ▲ Numerical formulas, chemical formulas, tables, etc. ▼ (II) (In the formula, R_3 and R_4 represent a hydrogen atom or a hydroxyl group. However, R_3 and R_4 do not simultaneously represent a hydrogen atom, and R_5 represents a group selected from the group consisting of a hydrogen atom, a halogen atom, a lower alkyl group, an alkoxyl group, an aryloxyl group, and a benzyloxy group. A heat-sensitive recording material characterized by using a combination of at least one compound selected from the group of sulfonyl diphenol compounds represented by (.) and stearyl gallate.