JPH025196B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention is applicable to applications that require pasting after printing, such as barcode labels and price display labels for POS (point of sale) systems, other delivery/shipping labels, product journal markings, stamps, and mailing stickers. This invention relates to a sheet for multicolor recording heat-sensitive labels. In recent years, POS systems have become extremely popular in large-scale mass retailers such as supermarkets and department stores, as well as chain specialty stores and restaurants. The purpose is to aggregate and analyze product sales information in order to clearly understand consumer needs and formulate rational business strategies.One of the purposes is the barcodes displayed on products sold in stores. Currently, the method of reading OCR characters with a scanner is rapidly developing, and it is expected that its use will further expand in the future for various types of slips, stamps, etc. Therefore, various printing methods are currently being tried, and among them, the thermal recording method can be said to be the most excellent. This is because the printing method uses chemical or physical changes in substances due to heating to record images, and does not require development and fixing, nor does it require replenishment of printing ink. That is, it has many features such as being able to downsize and simplify the machine and speed up recording, and there is no need to worry about ink staining hands or products or ink fading. However, barcode labels, price display labels, other slips, stamps, etc. have multiple entries, and users such as consumers and sales representatives are required to record them in multiple colors with vivid contrast. There is. Conventionally, there are many examples of multicolor thermal paper. Generally, it is possible to apply two or three heat-sensitive layers having different coloring temperatures and coloring hues. For example, a phenolic substance or an organic acid and two or more dye precursors that develop color with the phenolic substance or organic acid are used, and a single color is obtained by heating at a low temperature by utilizing the difference in melting point between the layers by laminating them.
A so-called mixed color system that produces different hues by mixing colors at high temperatures. (Japanese Patent Publication No. 15540-15540
In addition, by using a phenolic substance or an organic acid and two or more dye precursors that develop color with the phenolic substance or organic acid, the phenolic substance or organic By containing an organic base that melts at a higher temperature than an acid, it takes advantage of the fact that once a color develops when heated, it fades or disappears at a temperature above the melting temperature of the organic base, reducing the degree of color mixing and making it almost monochromatic. A so-called decolorizing type that produces different hues. (Unexamined Japanese Patent Publication No. 48-8251,
55-139290, JP-A-55-161688) Furthermore, by coexisting in such a system a dye precursor capable of developing a different color with the organic base,
The so-called simultaneous decoloring and coloring system (Special Publication Publication No. 51), which simultaneously develops different hues of a single color,
-37542). However, in the case of mixed color systems, the single color obtained by low-temperature color development has the disadvantage that the hue is limited to a much lighter hue than the mixed color obtained by high-temperature color development. i.e. red (low temperature)
- Black (high temperature), blue (low temperature) - black (high temperature), yellow (low temperature) - black (high temperature), etc., and a large amount of heat is required to print the black color that occupies the majority of the recorded area, making it difficult to save energy. This is not practical as it goes against speed. In addition, color separation is difficult, and the difference in melting point between layers must be sufficiently widened, resulting in a decrease in color development speed and a large amount of heat, which causes trouble during recording. In addition, in the case of color erasing systems, a basic substance is simply used as a color erasing agent, and when coloring at high temperatures, coloring is again done with phenolic substances or organic acids in the same way as low temperature coloring, resulting in high costs and interlayer formation. At present, there are many problems such as difficulty in balancing the mixture and a large amount of heat required. Therefore, the simultaneous decoloring and coloring system was invented to solve the above two problems.High temperature coloring progresses quickly using a basic substance that decolorizes low temperature coloring, and it is extremely efficient and clear. You can get many colors, including black (low temperature), red (high temperature), and blue (low temperature).
The advantage of being able to print frequently recorded characters such as red (high temperature), black (low temperature), and yellow (high temperature) at low temperatures is also applied to save energy and speed up recording. As we moved from an era when it was not possible to achieve the desired color, to an era when thermal printers and thermal facsimiles were desired to have multiple colors, it has become the system that can most likely meet expectations. However, the qualities required for heat-sensitive label sheets are (1) that the coating layer does not peel off and the recorded area remains clear and does not smear even if the sheet gets wet with water or gets wet from rain; (2) If your hands come into contact with edible oil such as tempura oil, hand cream or hair styling oil, or if you come into contact with packaging film containing a large amount of plasticizer for a long period of time, the recording section may become discolored and become difficult to read. Don't be impossible. There are two points to mention. In order to meet the requirement (1), it is possible to improve the effect to some extent by adding a water-resistant agent or water repellent to the water-soluble polymer compound used as a binder in the heat-sensitive coating layer, but the pigment contained in the coating layer It is impossible to form a complete film-like coating due to the influence of agents, dye precursors, etc.Also, increasing the amount of binder may be considered, but this results in a decrease in color development sensitivity. As a result of investigation, it has been found that the most effective method is to provide an overcoat layer that provides water resistance on the surface of the heat-sensitive layer. Also, this method
This also satisfies requirement (2). That is, it has been proposed that such a phenomenon will not occur if a plasticizer such as dibutyl phthalate, dioctyl phthalate, or dioctyl adipate forms a film for the purpose of preventing penetration into the heat-sensitive layer. (Unexamined Japanese Patent Publication 1973-
(No. 128347, Japanese Unexamined Patent Publication No. 54-3549) The present inventors also developed a chemical-resistant overcoat agent and filed applications in Japanese Patent Application No. 182557-1982 and Japanese Patent Application No. 981-1983. . However, when printing or stamping different hues on monochromatic thermal paper with an overcoat layer, the ink sets poorly because almost no penetration into the paper surface occurs, resulting in stains on hands and clothing, and poor marking. The drawback was that it was impossible to continue. As a result of investigation, it has been found that when an overcoat layer is provided on a heat-sensitive recording sheet capable of developing multiple colors, thermal printing and stamping can be easily and clearly performed in multiple colors. Based on these backgrounds, the inventors of the present invention have conducted intensive studies on sheets for thermal labels that can perform multicolor recording without staining printing or sealing, with the aim of satisfying the requirements (1) and (2). As a result, we have arrived at the present invention. That is, the present invention provides a support that has been subjected to a tack treatment, has a multicolor heat-sensitive layer on the other side that is a color-deleting and color-developing system simultaneously, and an alginate alone or an alginate as an essential component and another water-soluble layer on the surface. A multilayer film characterized by using one type or two or more types of polymeric compounds in combination and providing a film-like coating layer containing additives such as a water resistant agent, a water repellent, an antifoaming agent, and an ultraviolet absorber. To provide a heat-sensitive label sheet capable of color recording. The main components used in the present invention will be explained in detail below, but the present invention is not limited thereto unless it exceeds the gist of the present invention. Table 1 shows typical examples of dye precursors that develop color with phenolic substances or organic acids. Table 1 (1) Crystal violet lactone (2) 3-indolino-3-p-dimethylaminophenyl-6-dimethylaminophthalide (3) 3-diethylamino-7-chlorofluorane (4) 3-diethylamino -7-Cyclohexylaminofluorane (5) 3-diethylamino-5-methyl-7-t-
Butylfluorane (6) 3-diethylamino-6-methyl-7-anilinofluorane (7) 3-diethylamino-6-methyl-7-p-
Butylanilinofluorane (8) 2-(N-phenyl-N-ethyl)aminofluorane (9) 3-diethylamino-7-dibenzylaminofluorane (10) 3-cyclohexylamino-6-chlorofluorane ( 11) 3-diethylamino-6-methyl-7-xylidinofluorane (12) 2-anilino-3-methyl-6-(N-ethyl-p-toluidino)fluoran (13) 3-pyrrolidino-6-methyl- 7-anilinofluorane (14) 3-pyrrolidino-7-cyclohexylaminofluorane (15) 3-piperidino-6-methyl-7-toluidinofluorane (16) 3-piperidino-6-methyl-7- Anilinofluorane (17) 3-(N-methylcyclohexylamino)
-6-Methyl-7-anilinofluorane (18) 3-diethylamino-7-(m-trifluoromethylanilino)fluorane (19) 3-diethylamino-6-methyl-7-chlorofluorane Also, the present invention Dye precursors that develop color with organic bases include PH indicators that develop color or change color in alkaline conditions, fluorescein derivatives, and phenolphthalein derivatives. Substances such as ninhydrin derivatives that cause discoloration are used. Typical examples are shown in Table-2. Next, Table 3 shows typical examples of the phenolic substance or organic acid (color developer) used in the present invention. Table 3 (1) 4,4'-isopropylidene diphenol (2) 4,4'-isopropylidene bis(2-glolphenol) (3) 4,4'-isopropylidene bis(2-tert-butylphenol) ) (4) 4,4'-Secondary-butylidene diphenol (5) 4,4'-(1-methyl-n-hexylidene) diphenol (6) 4-phenylphenol (7) 4-hydroxydiphenoxide ( 8) Methyl-4-hydroxybenzoate (9) Phenyl-4-hydroxybenzoate (10) 4-hydroxyacetophenone (11) Salicylic acid anilide (12) 4,4'-Cyclohexylidene diphenol (13) 4,4' -Cyclohexylidenebis(2-methylphenol) (14) 4,4'-benzylidenediphenol(15) 4,4'-thiobis(6-tert-butyl-3-methylphenol) (16) 4,4' -isopropylidene bis(2-methylphenol) (17) 4,4'-ethylenebis(2-methylphenol) (18) 4,4'-cyclohexylidene bis(2-isopropylphenol) (19) 2,2 '-dihydroxydiphenyl(20) 2,2'-methylenebis(4-chlorophenol) (21) 2,2'-methylenebis(4-methyl-6-
(t-butylphenol) (22) 1,1'-bis(4-hydroxyphenol)
-Cyclohexane(23) 2,2'-bis(4'-hydroxyphenyl)
Propane (24) Novolac type phenolic resin (25) Halogenated novolac type phenolic resin (26) α-naphthol (27) β-naphthol (28) 3,5-di-t-butylsalicylic acid (29) 3,5-di-t-butylsalicylic acid -α-Methylbenzylsalicylic acid (30) 3-methyl-5-t-butylsalicylic acid (31) Phthalic acid monoanilide paraethoxybenzoic acid (32) Parabenzyloxybenzoic acid (33) Parahydroxybenzoic acid benzyl ester Furthermore, this book If the organic base used in the invention has a too low melting point or a very high water solubility, there is a high possibility that the heat-sensitive layer using it will change color during storage. If the heat-sensitive layer is too low, it is difficult for the heat-sensitive layer to discolor or develop color, which is not preferred from a practical standpoint. Among the organic bases used in the present invention, guanidine derivatives are particularly excellent in practical use, and specific examples are listed in Table 4A, but these are not intended to limit the present invention. In the table, H represents a cyclohexyl group. Organic bases that can be used in the present invention other than the above-mentioned guanidine derivatives are shown in Table 4B, but are not limited to the present invention. Table 4B (49) Phenylthiourea (50) Hexadecylamine (51) Tribenzylamine (52) N, N, N', N'-Tetrabenzyl-ethylenediamine (53) N, N, N', N'- Tetrabenzyl-hexamethylene diamine (54) Decamethylene diamine (55) Tricyclohexylamine (56) N,N'-dibenzylpiperazine (57) Dioctadecylamine (58) 2-Aminobenzoxazole (59) 2-Aminobenzo Thiazole (60) 2-Aminobenzimidazole (61) Quinine (62) Cyclohexyldibenzylamine (63) Octadecylbenzylamine The thermal recording paper of the present invention can be obtained by the following method. That is, a phenolic substance or an organic acid, a dye precursor that develops color with the phenolic substance or organic acid, an organic base, and a dye precursor that develops a color with the organic base are separately or simultaneously pulverized into fine particles using a pulverizer. A coating liquid is prepared by pulverizing and dispersing, mixing with a binder, pigment, etc. in an appropriate combination, and adding various additives as necessary. Examples of the binder include water-soluble binders such as starch, hydroxyethylcellulose, methylcellulose, polyvinyl alcohol, styrene-maleic anhydride copolymer, styrene-butadiene copolymer, polyacrylamide, carboxymethylcellulose, gum arabic, and casein. , styrene-butadiene latex, and the like can be used. Examples of pigments include aluminum hydroxide,
Heavy and light calcium carbonate, zinc oxide, titanium oxide, barium sulfate, silica gel, activated clay, talc, clay, satin white, kaolinite,
Calcined kaolinite, diatomaceous earth, synthetic kaolinite, polyolefin grains, polystyrene grains, urea.
Examples include formalin resin particles. Next, regarding the material forming the overcoat layer in the present invention, water-soluble polymer compounds are generally preferred, among which alginate alone or alginate is essential, hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, It is preferable to use one or more polymer compounds selected from polyvinyl alcohol in combination. (Japanese Patent Application No. 56-152455) Furthermore, one or more types of water resistance agents, water repellents, antifoaming agents, and ultraviolet absorbers are used in combination to impart water resistance and light resistance, and to eliminate pinholes. It is preferable to use one that prevents occurrence. Further, in the present invention, the thickness of the overcoat layer as a dry film is 0.5 μm or more, preferably,
A thickness of 3 to 12 μm is desirable from the viewpoint of heat-sensitive properties, oil and fat resistance, and plasticizer resistance. If the film thickness is thinner than 0.5 μm, the heat-sensitive property will not be sufficient to prevent dust/states king and fingerprint stains, and the oil/plasticizer resistance will be insufficient. Although it has good resistance to oils and fats and plasticizers, it tends to cause a decrease in color development sensitivity. Next, the present invention will be specifically explained with reference to the drawings. Note that this is an example of a combination of various materials and a coating method, and the combination, single layer, laminated, etc. coating method does not limit the present invention. The figure is a cross-sectional view of a sheet for heat-sensitive labels of the present invention, in which a support 3 is provided with a pressure-sensitive adhesive (hereinafter referred to as adhesive) layer 2 with a release paper 1 attached thereon, and the other side is provided with a pressure-sensitive adhesive (hereinafter referred to as adhesive) layer 2. -A and a layer 4 which has the function of a decolorizing agent and a coloring agent when heated at high temperature and whose main components are the organic bases shown in Table 4-B, and the phenolic substances or organic acids shown in Table 3 and Table 1 Dye precursors capable of developing color when heated with the phenolic substance or organic acid shown in Tables 4-A and 4-B
A dye precursor that develops a monochrome color when heated at a low temperature, the main component of which is a dye precursor that can develop a color when heated with the organic base shown in
Coloring layers 5 that develop different hues when heated at high temperatures are sequentially laminated. On these thermosensitive coloring layers,
In addition, alginate alone or alginate as an essential component may be added to other water-soluble polymer compounds.
Overcoat layer 6 using seeds or a combination of two or more kinds
is provided. More specifically, as release paper, for example, paper whose surface has been treated with a release agent such as silicone resin is generally used, but as a base, in addition to paper, synthetic paper, synthetic resin It can also be used with film, etc. Examples of adhesives include hot-melt adhesives mainly containing styrene-butadiene block copolymers, styrene-isoprene block copolymers, etc., rubber emulsion-type adhesives such as natural rubber latex, isobutylene latex, etc.
Examples include acrylic emulsion type adhesives, but this does not limit the invention unless it goes beyond the gist of the invention. The support to which the heat-sensitive coating liquid is applied is generally paper, but any material such as synthetic paper or synthetic resin film can also be used. Next, examples of the present invention will be described in detail with reference to the drawings. Example A liquid 3-diethylamino-6-methyl-7-anilinofluorane...200g Maron MS-25 (manufactured by Daido Kogyo Co., Ltd., styrene)
25 of sodium salt of maleic anhydride copolymer
% aqueous solution)...24g Water...276g Solution B 4,4'-isopropylidene diphenol
...200g Maron MS-25 ...24g Water ...276g Solution C 2,4,5,7-tetrabromofluorescein (compound (50) in Table 2) ...125g 5% hydroxyethylcellulose aqueous solution
...125g Water ...373g Solution D 1,3-dicyclohexyl-2-phenylguanidine (compound (7) in Table 4A) ...150g 5% hydroxyethylcellulose aqueous solution
...150g Water ...200g The above liquids A, B, C, and D were separately ground and dispersed in a ball mill for 48 hours. A heat-sensitive coating liquid was prepared using the liquids A, B, C, and D thus dispersed as follows. Undercoat layer coating liquid: Layer 4 in the figure D liquid...10g 10% hydroxyethyl cellulose aqueous solution
......12g Water...8g The coating liquid prepared as above was applied to base paper with a basis weight of 50g/ ^m2 so that the coating weight after drying was 3.6g/ ^m2 ,
The undercoated paper was prepared by drying at 60°C for 1 minute. Top coat layer coating liquid: Layer 5 in the figure Ancilex (manufactured by Engelhard KK,
Calcined kaolin)...20g Part A...4g Part B...15g Part C 6g 20% by weight stearamide emulsion manufactured by Chukyo Yushi Co., Ltd., Hydrin M-7)...15g Maron MS-25...22g Water ...55g Coating solution prepared as above was applied onto the undercoat paper so that the coating amount after drying was 7.4g/ ^m2 , and 60g
It was dried for 1 minute at ℃ to produce a multicolor thermal paper with simultaneous decolorization and color development. The multicolor thermal paper developed a color with a sharp contrast of black when heated at low temperature and red when heated at high temperature. Overcoat layer: Layer 6 in the figure is sodium alginate/carboxymethyl cellulose = 1/1
(Weight ratio) Epoxy crosslinking agent (product name:
Epiol G-100 (manufactured by NOF) at a weight ratio of 0.1
The film was added to the multicolor thermal paper and coated on the multicolor thermal paper so that the thickness of the film after drying was approximately 4 μm.After drying, it was supercalendered and laminated with tactile paper.
The desired multicolor recording heat-sensitive label sheet was obtained. The sheet for multicolor recording heat-sensitive labels obtained in this way can print images with a clear contrast between black and red, and has the light resistance required for uses such as labels.
Fully satisfies water resistance, oil and fat resistance, and plasticizer resistance,
Furthermore, no scum or statesking was observed during printing, which was satisfactory.

[Brief explanation of drawings]

The figure is a sectional view of a sheet for a multicolor recording heat-sensitive label of the present invention. 1...Release paper, 2...Adhesive layer (shaded area), 3
...Support, 4...A layer having the function of decolorizing agent and coloring agent when heated at high temperature, 5...Layer that obtains a monochromatic color when heated at low temperature and obtains color development of another hue when heated at high temperature, 6...
...Overcoat layer (dots), ○ mark...phenolic substance or organic acid, ◎ mark...dye precursor that develops color when heated with phenolic substance or organic acid, × mark...organic base, mark...organic Each shows a dye precursor that develops color when heated with a base.

Claims (1)

[Claims] 1. In a tack-processed paper formed by providing a pressure-sensitive adhesive layer on one side of a support and further attaching a release paper,
On the other side of the support, a phenolic substance or an organic acid, a dye precursor that can develop color when heated with the phenolic substance or organic acid, an organic base, and a dye precursor that can develop color when heated with the organic base. Alginate alone, or alginate as an essential component, and one or more other water-soluble polymer compounds on the surface of the multicolor heat-sensitive layer formed by appropriately combining them as main elements in a single layer or in a laminated manner. A multicolor recording heat-sensitive label sheet characterized by having an overcoat layer used in combination.