JPS61160290A - Thermal recording sheet - Google Patents

Abstract

PURPOSE:To provide a thermal recording sheet having excellent effect in the prevention of image deterioration, by using a specific olefin diolefin polymer in a thermal recording sheet. CONSTITUTION:In a thermal transfer sheet containing a coupler 4,4'- dihydroxyphenyl-2,2-propane forming a color through the reaction with a colorless - light colored dye precursor at the time of heating, 1,1,3-tri(3-tertiary- butyl-4-hydroxy-6-methylphenyl)butane and a 5C olefin diolefin polymer are together used. As the support used in the thermal transfer sheet, paper is used mainly but various nonwoven fabrics, plastic films, synthetic papers, metal foils or composite sheets comprising combinations thereof are arbitrarily used.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a thermosensitive recording sheet.

(b) Conventional technical records 1 As a stabilizer to improve the storage stability of images,
9-45747, JP-A-54-18752, and JP-A-57-83495 disclose the addition of a phenolic antioxidant.

(C) Purpose of the Invention However, some of these problems may cause a decrease in sensitivity, unnecessary color development during storage of recording paper, or long-term touching of the recorded image area with hairdressing or oily hands. As a result, the image area deteriorates, and no satisfactory improvement in image stability has been found.

That is, the present invention is aimed at solving the conventional drawbacks, and is capable of eliminating scalp fogging and deterioration of sensitivity, and improving image stability, especially when the recorded image area is coated with oily substances such as hair conditioners. The object of the present invention is to provide a heat-sensitive recording sheet If that is highly effective in preventing image deterioration (grease resistance) caused by prolonged contact.

B) Structure of the Invention The present invention uses a color developer 4,4'- which reacts with a normally colorless or light-colored dye precursor upon heating to develop color from the dye precursor.
In a heat-sensitive recording sheet containing dihydroxydiphenyl-2,2-propane, 1.1.3-)su(3-tert-butyl-4-hydroxy-6-methylphenyl)
Butane and an olefin diolefin polymer having 5 carbon atoms are used together.

Although the main components used in the present invention will be specifically explained, the present invention will not be exhaustive unless it goes beyond the gist of the present invention.

(1) Dye precursor Dye precursors commonly used for thermal paper can be used, such as crystal violet lactone, 3-diethylamino-7-methylfluoran, 3-diethylamino-6-
Chloro-7-methylfluorane, 3-diethylamino-
6-methyl-7-chlorofluorane, 3-diethylamino-7-anilinofluorane, 3-diethylamino-7
-(2-chloroanilino)fluoran, 3-ethylamino-6-methyl-7-anilinofluoran, 3-dibutylamino-7-(3-chloroanilino)fluoran, 3
-(N-ethyl-P-toluidino)-6-methyl-7-
Anilinofluorane, 3-(N-methylcyclohexylamino)-3-methyl-7-anilinofluorane, 3-
piperidino-3-methyl-7-anilinofluorane and the like.

(2; Binders such as starches, hydroxyethyl cellulose, methyl cellulose, polyvinyl alcohol, styrene-maleic anhydride coelectrolyte, styrene-butadiene copolymer,
polyacrylamide etc.

(3) Pigments such as diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, titanium oxide, zinc oxide, silicon oxide, aluminum hydroxide, urea-formalin resin, etc.

In addition, waxes include stearic acid amide, polyethylene, carnauba wax, paraffin wax, castor wax, halafine oxide, polyethylene oxide,
A dispersion or emulsion of zinc stearate, calcium stearate, etc. may be added.

Moreover, various other auxiliary agents can also be added.

Examples include dispersants such as sodium dioctyl sulfosuccinate, ultraviolet absorbers and antifoaming agents such as benzophenone and benzotriazole, fluorescent dyes, and colored dyes, but these are not sufficient. . □ Paper is mainly used as the support for the heat-sensitive recording sheet according to the present invention, but various nonwoven fabrics, plastic films, synthetic papers, metal foils, etc., or composite sheets made of a combination of these can also be used as desired.

(E) Example 1 (1) Solution A (dye precursor dispersion) 150 parts of 3-diethylamino-6-methyl-7-anilinofluorane was dissolved in 25 parts of styrene-maleic anhydride copolymer sodium salt in water. g, 30 parts were dispersed in 214 parts of water, and pulverized and dispersed in a ball mill for 48 hours.

(2) Solution B (w4 colorant and stabilizer dispersion) 4.4'
-140 parts of dihydroxydiphenyl-2,2-propane, 24 parts of 1,1,3-tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane, olefin diolefin polymer having 5 carbon atoms 10% of 24 copies, P
It was dispersed in 94 parts of VA aqueous solution and 280 parts of water, and pulverized and dispersed in a ball mill for 48 hours.

(3) Formation of heat-sensitive recording layer 180 parts of liquid A, 700 parts of liquid B, 280 m of calcium carbonate
120% stearamide dispersion ff400 parts, PVA
Thermal coating Wlr basis weight 50 f/rr? was obtained by mixing and stirring 10% aqueous gsoo part and 100 parts of water. The mixture was coated on base paper so that the coating amount after drying was 5.0 t/lri, dried, and treated with a super calendar to obtain a heat-sensitive recording sheet.

Example 2 (1) A paint precursor dispersion was prepared in the same manner as Liquid A in Example 1.

(2) Liquid C (dispersion liquid of IJ colorant and stabilizer) 4.4'
-140 parts of dihydroxydiphenyl-2,2-propane, 12 parts of 1,1.3-)su(3-tert-butyl-4-hydroxy-6-methylphenyl)butane, olefin diolefin polymer having 5 carbon atoms, Combined 24 parts f: 10%,
It was dispersed in 88 parts of PVA aqueous solution and 230 parts of water, and pulverized and dispersed in a ball mill for 48 hours.

(3) Formation of heat-sensitive recording layer 180 parts of liquid A, 680 parts of liquid C, 280 parts of calcium carbonate, 400 parts of 20stearic acid amide dispersion, 10% P
A heat-sensitive coating liquid obtained by mixing and stirring 750 parts of VA aqueous solution and 95 parts of water was applied to a base paper with a basis weight of 50 ψ with a coating amount of 5.0 after drying.
It was coated to a thickness of 2 ml, dried, and treated with a super calendar to obtain a heat-sensitive recording sheet.

Example 3 (1) A dye precursor dispersion was prepared in the same manner as Solution A of Example 1.

(2) Solution D (dispersion liquid of color developer and stabilizer) 4.4'-
120 parts of dihydroxydiphenyl-2,2-propane,
1.1.3-tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane 38 parts, carbon number 5
24 parts of olefin diolefin polymer, 120 parts of ethylene bisstearamide were added to 10 parts of PVA water age g1
50 parts and 450 parts of water, and pulverized and dispersed in a ball mill for 48 hours.

(3) Formation of heat-sensitive recording layer 140 parts of liquid A, 900 parts of liquid The mixture was coated and dried on the spine base paper so that the coated amount after drying was 8.0%, and treated with a supercalender to obtain a heat-sensitive recording sheet.

Example 4 (1) A dye precursor dispersion was prepared in the same manner as Solution A of Example 1.

(2) Liquid E (dispersion liquid of color developer and stabilizer) 4.4'-
120 parts of dihydroxydiphenyl-2,2-propane,
1,1.3-tri(3-tert-butyl-4-hydroxy-6-methylphenyfur)butane 19 parts, olefin diolefin electrolyte having 5 carbon atoms 24 parts, ethylene bisstearamide 120
%, 10% PV,' was dispersed in 140 parts of an aqueous solution and 400 parts of water, and pulverized and dispersed in a ball mill for 48 hours.

(3) Formation of heat-sensitive recording layer 140 parts of liquid A, 870 parts of liquid E, 250 parts of aluminum hydroxide,
A heat-sensitive coating liquid obtained by mixing and stirring 1500 parts of a 10% PVA aqueous solution and 300 parts of water was dried on a base paper with a total basis weight of 50 f/rrl so that the coating amount after drying was 8.0η.
A thermosensitive recording sheet 1 was obtained by processing with a supercalender.

Comparative Example I A thermal recording sheet (f) was obtained in the same manner as in Example 1 except that the olefin diolefin polymer having 5 carbon atoms was not used in the B'ig formation.

Comparative Example 2 In preparing liquid B, except that 1.1.3-tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane and C5 olefin diolefin polymer were not used. A thermosensitive recording sheet was obtained in the same manner as in Example 1.

Comparative Example 3 A thermosensitive recording sheet If was obtained in the same manner as in Example 3 except that the olefin diolefin polymer having 5 carbon atoms was not used in the 11-part component.

Comparative Example 4 Except that the olefin diolefin polymer having 5 carbon atoms and 12 parts of 1,1,3-)s(3-tert-butyl-4-hydroxy-6-methylphenyl)butane were not used in the preparation of Liquid D. A thermosensitive recording sheet was obtained in the same manner as in Example 1.

The heat-sensitive recording sheets of Examples 1 to 4 and Comparative Examples 1 to 4 were recorded using a heat-sensitive facsimile (Oki FAX 7100), and the following storage test was conducted. The results are shown in Table 1.

a. Heat resistance test: The residual rate of the image and the density of the background were measured when the image was stored at 50° C. for 7 days.

b. Moisture and heat resistance test: The image survival rate and background density were measured when the image was stored for 7 days at 40°C and humidity of 90q6.

C6 Grease Resistance Tasting: Write down the image area with a felt marker filled with castor oil, then draw a thin layer of castor oil on the image area.
The image was stored at 0° C. for 7 days, and the residual rate of the image was measured.

In addition, both numerical values and Macbeth 1 were measured using D-514 (for Raften A106 filter stool).

Table 1 From Table 1, it can be seen that the present invention has excellent storage stability, particularly oil resistance, of recorded images.

(f) Effects of the Invention As described above, the present invention has the effect of improving the storage stability of recorded images, especially the oil resistance.

Claims (1)

[Claims] In a heat-sensitive recording sheet containing a color developer 4,4'-dihydroxydiphenyl-2,2-propane, which reacts with a normally colorless to light-colored dye precursor upon heating to develop color from the dye precursor, 1,1,3 - A heat-sensitive recording sheet characterized by using a combination of tri(3-tert-butyl-4-hydroxy-6-methylphenyl)butane and an olefin diolefin polymer having 5 carbon atoms.