KR830002218B1 - Thermal recording sheet - Google Patents

Abstract

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Description

Thermal recording sheet

An infection recording sheet comprising at least one compound represented by the following general formula (I) of the present invention as a developer.

Wherein R represents hydrogen, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aralkyl group having 7 to 10 carbon atoms, and a phenyl group, which may be the same or different from each other n is 0 or an integer of 1 or 2).

Conventionally, clays such as triphenylmethane, fluorane-based, phenothiazine-based, orramine-based, spiropyran-based coloring agents (hereinafter referred to as colorants) and activated clays, clays and phenol compounds Heat of a so-called dye-coloring type, characterized by obtaining a color image by contacting a positively colored material by heat using a color reaction with a colorant composed of a solid acid such as an aromatic carboxylic acid or an aromatic polyvalent metal salt. Recording sheets have been widely known.

In general, the thermal recording sheet should be itself colorless or pale as a performance condition, and should have excellent color development performance as well as good color development, which does not change immediately after sheet production and after long-term storage, and is sufficiently stable against light or humidity. It should be economically manufacturable. The thermal recording developer and sheet coated thereon have already been proposed, and these thermal recording sheets are colored before heating when radiated because two reactants are contacted and carried on the support. The development of excellent thermal recording sheets has been desired because of the drawbacks of blackening, poor storage resistance such as light resistance and water resistance, and lack of color development at the time of heating. In particular, in recent years, there has been a demand for the appearance of a novel developer having a good increase in color density at the instant of heating and having a gradation for a high-speed printer having a short thermal pulse width.

An object of the present invention is to provide a heat-sensitive recording sheet having a good increase in color development concentration in a heated pure garner.

The above object of the present invention is a 2, 2'-bisphenol sulfide (n = 0), 2, 2'-bisphenol sulfoxide and 2, 2'-bisphenol sulfone represented by the following general formula (I) as a developer It can achieve by providing the thermal recording sheet characterized by containing 1 or more types of compound.

(Wherein R represents hydrogen, an alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an allalkyl group having 7 to 10 dehydration atoms, and a phenyl group, and may be the same or different from each other) Good, n or an integer of 1 or 2).

The thermal recording sheet according to the present invention is extremely sensitive to the increase in color development concentration and exhibits the same or more color development concentration as compared with the conventional thermal recording sheet using bisphenol A.

The thermal recording sheet according to the present invention is extremely advantageous in handling and preservation, and the color image has good light resistance and water resistance, the concentration of the color image is very low over time, and can be produced at low cost. It has an advantage.

Examples of the developer represented by the general formula (I) include the following compounds, such as

2, 2'-diphenol sulfide, 2. 2'-diphenol sulfoxide,

2, 2'-diphenolsulfone, 2. 2'-bis (p-cresol) sulfide,

2, 2'-bis (p-cresol) sulfoxide, 2, 2'-bis (p-cresol) sulfone,

2, 2'-bis (p-isopropylphenol) sulfone,

2, 2'-bis (p-tert butylphenol) sulfone,

2, 2'-bis (p-tert butylphenol) sulfide,

2, 2'-bis (p-tert butylphenol) sulfoxide,

2, 2'-bis (p-tert butylphenol) sulfone,

2, 2'-bis (p-tertiary amylphenol) sulfide,

2, 2'-bis (p-tertiary amylphenol) sulfoxide,

2, 2'-bis (p-cyclonuxylphenol) sulfide,

2, 2'-bis (p-cyclonuxylphenol) sulfone,

2, 2'-bis (p-cumiphenol) sulfide, 2, 2'-bis (p-phenylphenol) sulfoxide,

2, 2'-bis (p-cumiphenol) sulfone, 2, 2'-bis (p-phenylphenol) sulfoxide,

2, 2'-bis (p-phenylphenol) sulfone,

2, 2'-bis (p-tertiary octylphenol) sulfoxide,

2, 2'-bis (p-tertiary octylphenol) sulfone,

2, 2'-bis (d-dodecylphenol) sulfide,

2, 2'-bis (p-dodecylphenol) sulfoxide,

2, 2'-bis (p-dodecylphenol) sulfone, etc. can be mentioned, It is not limited only to these compounds.

The production method of the infection recording sheet of the present invention will be described below. As a coloring agent which can be used for this invention, the developing agent represented by General formula (I) and the various substance developed by melt reaction can be used, These names 3, 3 '-(4-dimethylaminophenol) -6- Dimethylaminophthalide (cristine violet lactone), 3-diethylamino-6-methyl-7-chlorofluorofluorane, 3-diethylamino-7-chlorofluorane, 3-cyclonucleosilamino-6-chloro Fluorane, 3-diethylamino-7-dibenzylaminofluorane, 3-diethylamino-6-methyl-7-phenylaminofluorane, 1, 3, 3, -trimethylindolin-6'-chloro- 8'-methoxyspiropyrane can mention electron co-dyeing compounds, such as 3-methyl-2 and 2'-spiro bis (benzo [f] chromen).

The colorless or pale color developing agent, the color developing agent represented by the general color (I), or a mixture with the color developing agent, the developing agent, and the hot melt substance is well dissolved in a solution or a dispersed solution in which the binder is dissolved in water or an organic solvent. The mixed liquid mixture is prepared.

Examples of the binder used in the preparation of the mixed solution include styrene butadiene polymer, polyvinyl alcohol, carboxymethyl cellulose, polystyrene, synthetic polymers such as vinyl chloride-vinyl acetate copolymer and gum arabic, natural or naturally modified polymers. have. Moreover, when the solvent which can be used is illustrated, organic solvents, such as benzene, toluene, acetone, methylene chloride, ethyl acetate, and a cyclo nucleic acid, can be enumerated.

The mixed solution thus obtained is applied and dried on a support such as paper, natural or synthetic resin film. The mixed solution may be impregnated in the support. The mixing method and the coating method are not limited to the thermal recording sheet of the present invention. For example, the coloring agent may be mixed with a binder solution, and the developer may be separately mixed with a binder solution, and then the positive mixture may be mixed together and applied on a support, or the two mixtures may be separately separated into two times. It can also be applied onto the support.

Both mixtures may be applied to the same side or the other side of the support, or may be applied to the other support, respectively.

The coating amount is generally at least 0.5 g / m 2, preferably 1 to 10 g / m 2, based on the dry weight.

The relative amount of each component constituting the thermal recording sheet is wide, but the preferred range is 1 to 15 parts by weight for the color developer based on dry weight, and 1 to 15 parts by weight for the developer represented by the general formula (I). 95 parts by weight and the binder is 1 to 40 parts by weight.

The thermal recording sheet according to the present invention has no blackening phenomenon due to color development, regardless of contact between the colorant and the active agent during manufacture, from application drying to heating, and exhibits no deterioration in color performance even when the sheet is exposed before radiation. As a result, the safety with time is good, and color is instantaneously generated during heating. In addition, the image developed is extremely good in light resistance and water resistance.

The present invention is described in more detail by enumerating the following examples. The measuring method and evaluation of various performances of the recording sheet are described below.

1) Color concentration:

The recording sheet was heat-colored under the following conditions using Thermotest Rhodiaceta (manufactured by SETARAM, type 7401).

5 seconds heating time

10 g / cm2 pressure between heating element and recording sheet during heating

Heating temperature range 60-180 ℃

The reflectance (I) was measured for 10 minutes after heating using a amber filter for TSS type Hunter colorimetric crab. The lower the reflectance, the higher the color development.

2) Light fade resistance of color development:

The sheet developed in the method of 1) was irradiated with a carbon arc for 30 minutes to 6 hours and then measured using a Hunter colorimeter as in the method of 1).

In other words,

Io: reflectance of the uncolored sheet,

Is: reflectance of the color sheet before irradiation;

In: Using the reflectance of the coloring sheet after n hours of irradiation, respectively,

The higher this was, the more preferable.

3) storage stability;

After leaving undeveloped and developed recording sheets at 25 ° C. for 6 months, the reflectances of the undeveloped and developed sheets before standing were set to Ko and Ko ', and the reflectances after leaving were set to K and K', respectively, and K-Ko and Preservation stability is so preferable that K'-K'o is the next.

4) water resistance;

2 hours was preserve | saved in water of the recording sheet example which developed color, and the density change of the color development was observed visually.

Example 1

Liquid A: Crystal violet lactone 7g Liquid B: 2, 2'-bis (p-cresol) sulfide 7g

10% weight polyvinyl alcohol 10% weight polyvinyl alcohol 30 g

(Kurare 217) 30 g water 13 g

13 g of water

The liquid A and liquid B were separately prepared in a sand gliding mill, and the liquid A and liquid B were mixed with 67 parts of each of three bags, so that the dry coating amount was 2.5 to 3.5 g / m 2 on the high-quality paper. The coating was dried to obtain a thermal recording sheet. The performance evaluation of the obtained thermal recording sheet was performed, and the results are shown in the first table.

[Examples 2 to 10 and Remarks 1]

The thermal recording sheet was exemplified by repeating the operation of Example 1 except that another developer was used instead of the developer used in Example 1. The performance evaluation of the opened thermal recording sheet was performed. The results of the developer and the performance evaluation used in the first table are described.

[Table 1]

* (a), (a '): before preservation * (c): water resistance * (b), (b'): after 6 months

Claims (1)

Developer, colorant and binder, characterized in that at least one of 2, 2'-bisphenol sulfide, 2, 2'-bisphenol sulfoxide and 2, 2'-bisphenol sulfone compounds represented by the following general formula (I): Heat-sensitive recording sheet produced by applying or impregnating on a sheet support.

Wherein R represents a cycloalkyl group having 1 to 12 hydrogen atoms and an aralkyl group having 3 to 10 carbon atoms, and may be the same or different from each other, and n is an integer of 0, 1 or 2.