JPS6018385A - Chemical-resistant thermal recording paper with improved surface characteristics - Google Patents

Abstract

PURPOSE:To obtain a thermal recording paper having excellent surface characteristics and hardly deteriorated at white paper parts and developed color parts thereof by chemicals, by a method wherein an overcoat layer comprising a water-soluble polymeric compound as a main constituent and comprising a slicone rubber is provided on a thermal color forming layer. CONSTITUTION:The thermal recording paper comprises the thermal color forming layer comprising as main constituents a colorless or light-colored dye precursor and a color developer for developing the color of the dye precursor by reacting with the precursor when being heated, on which is provided the overcoat layer comprising a water-soluble polymeric compound as a main constituent and comprising a silicone rubber. The silicone rubber is favorably used in an amount of not less than 0.5wt%, preferably, 1- 40wt%, from the viewpoints of surface characteristics, color forming sensitivity and printability. If the amount is less than 0.5wt%, effects in preventing blocking or abnormal gloss can not be obtained. On the other hand, if the amount is more than 40wt%, smoothness is not enhanced in super calender finishing, so that close contact of the paper with a thermal head can not be achieved and the color forming sensitivity and printability are degraded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermal recording paper whose main components are a dye precursor and a color developer that develops color when the dye precursor is heated. The present invention provides a heat-sensitive recording paper that is less susceptible to deterioration due to chemicals.

Thermosensitive recording paper consists of: (1) carbon or colored dyes and pigments are fully coated on a substrate, and an opaque thermofusible substance is coated on top of that; the opaque layer becomes transparent when heated, and the colored layer underneath becomes transparent; The method by which an image is formed.

(2) Method of forming a complex compound between a stain donor and an electron acceptor by heat. (3) There is a method in which a dye precursor such as crystal violet lactone and an acidic developer such as a 7-enol compound are dispersed and applied discontinuously, and one or both are dissolved by heating to develop color. Among these methods, method (3) is used in general facsimile machines, printers, etc. because it is superior overall in terms of image clarity, ML embossment, image color tone, and problems with scum.

The characteristics required for this type of 16-thermal recording paper include, of course, sensitivity suitable for various uses, white background, and long-term stable colored images that do not fade. It ensures that no residue is generated during recording, and that it does not stick to the thermal head during recording. Although superior products can be made that meet many of these requirements,
In terms of practical handling after recording, if it comes into contact with an eraser or a vinyl chloride bag that contains a large amount of plasticizer, or if it comes into contact with a hand that has been covered with hand cream or hair styling oil,
When overlaid with diazo photosensitive paper immediately after processing, the image disappears and the background color becomes blurred, making it difficult to read the recording image. It has the disadvantage of becoming. This discoloration phenomenon is thought to be due to the fact that the rough dragonfly of the color-forming lactone compound, which has been ring-opened with an acidic color developer, is ring-closed in the presence of a plasticizer such as dibutyl phthalate, dioctyl phthalate, or dioctyl adipate. There is. It is also believed that the fogging phenomenon is caused by the developer of the diazo photosensitive paper and the solvent contained in the fluorescent pen completely dissolving the color developer and bringing it into contact with the dye before the dye, causing a color reaction.

Therefore, it has been proposed that this phenomenon can be prevented by forming a film on the thermosensitive recording paper to prevent the plasticizer from penetrating. (JP-A-54-128347, JP-A-54
-3549) The present inventors have also developed an overcoat agent having mulberry resistance and filed applications in Japanese Patent Application No. 55-1s25s7 and Japanese Patent Application No. 56-981.

However, regarding the surface properties of the overcoat layer,
Since it is composed entirely of water-soluble and molecular compounds, it causes marking blocking, that is, the phenomenon in which the front and back sides of a roll of paper are partially in contact with each other.1. The coating layer peels off during the processing stage, destroying the overcoat layer and causing deterioration of chemical resistance. Another piece of paper? ! : It is not easy to cause, and it significantly impedes work efficiency. In addition, (b) the surface smoothness becomes higher, and the current situation is that it becomes softer than general thermal paper that has not been overcoated, resulting in poor writeability and abnormal gloss.

To meet the requirement (a), it is possible to improve the effect to some extent by adding a water-resistant agent to the water-soluble polymer compound used in the overcoat layer or a release agent such as silicone oil. Complete water resistance is practically impossible in 4. In addition, if the amount is large, it will cause repellency and color development inhibition.In order to satisfy the requirement (b), it is possible to add white pigment, etc. However, there is a limit to how much it can inhibit the formation of a film-like film or cause a decrease in color development sensitivity.

The inventor's objectives are to have chemical resistance, no pronking, and (1) writeability and surface gloss that are no different from ordinary thermal paper without overcoat treatment. = Aimed at, no scum, no sticking,
As a result of extensive research into thermosensitive recording paper that does not inhibit color development or decrease sensitivity and has good print quality, the present invention was arrived at.

(1) The present invention improves the surface susceptibility of the thermal recording paper of the method (3) above by incorporating silicone rubber into the overcoat layer, which is entirely composed of a water-soluble polymer compound. The purpose is to provide chemical-resistant thermal paper.

The main components used in the present invention will be explained in detail below, but the present invention is not limited thereto unless it goes beyond the gist of the invention.

Typical examples of dye precursors that develop color with phenolic substances or organic acids are shown in Table 1. (1) Crystal violet lactone (2) 3-indolino-3-P-dimethylagunophenyl-6-dimethylamino Phthalide (3) 3-diethylamino-7-glorofluorane (4) 3-diethylamino-7-cyclohexylaminofluorane (5) 3-diethylamino-5-methyl-7-t-buterfluorane (6) 3-diethylamino-6- Methyl-7-anilinofluorane (7) 3-diethylamino-6-methyl-7-P-buteraninunofluorane (8) 2-(N-phenyl-N-ethyl)aminofluorane (9) 3-diethylamino-7 -dibenzylaminofluorane (10) 3-cyclohexylamino-6-chlorofluorane (11) 3-diethylamino-6-methyl-7-xylidinofluorane (b)) 2-anilino-3-methyl-6- (N-Ethyl-p-toluidino) fluorane αa) a-pyrrolidino-6-, 1' tyro-anilitufluorane σ4) 3-:' lolidino-7-cyclohexylaminofluorane (15) 3-piperidino- 6-Methyl-7-F luidinofluorane (6) 3-piperidino-6-methyl-7-anilinofluorane (x7) 3-(N-methylcyclohexylamino)-6
-Methyl-7-anilinofluorane 08) 3-diethylamino-7-, (m-)lifluoromethylanilino)fluoran (19) 3-diethylamino-6-methyl-7-chlorofluorane Next, the present invention Table 2 shows typical examples of phenolic substances or organic acids (color developers) used for 4.4'-isozolobylidene diphenol (2
) 4.4'-Impropylidene bis(2-glorphenol) (3) 4.4'-Impropylidene bis(2-tertiary tatylphenol) (414,4'-secanglypteridene diphenol (5) 4.4'-(1-methyl-n-hexylidene)diphenol (6) 4-phenylphenol (7) 4-hydroxydiphenoxide (8) Methyl-4-hydroxybenzoate (9)
Phenyl-4-hydroxybenzoate (zo) 4-
Hydroxyacetophenone 01) Salicylic acid anilide α2) 4゜4I-cyclohexylidene diphenol (1)
3) 4,4 I-cyclohexylidene bis(2-methylphenol) (14) 4.4'-benzylidene diphenol (z
s) 4.4 +-thiobis(6-tert-butyl-3-methylphenol) (46) 4.4'-impropylidenebis(2-methylphenol) (17) 4.4'~ethylenebis(2- Methylphenol) αB) 4.4'-Cyclohexylidenebis(2-iso70robylphenol) (19) 2.21-dihydroxydiphenyl (20)
2.2'-methylenebis(4-chlorophenol)G
! 1) 2.2'-methylenebis(4-methyl-6-
(t-butylphenol) (22) 1.11-bis(4-hydroxyphenol)
-Cyclohexane (23) 2.2-bis(4t-hydroxyphenyl)
Propane (2 units, novolac type phenol ffEl fat G15)
Halogenated novola ivy type phenolic resin (26) α-
Naphthol (27) β-naphthol (28) 3.5-di-t-butylsalicylic acid (29)
3. s-di-α-methylbenzylpurinalic acid (ao
) 3-Methyl-5-t-butylsalicylic acid (30 phthalic acid monoanilide no ξ laethoxynu c) (32)
Rose benzyloxybenzoic acid (aa) Rose hydroxy E breath g benzyl ester The thermal recording paper of the present invention can be produced by the following method. ◇That is, phenol 9
Abundant or organic acids, such as phenols, 4 or 1 (
, Difference , Step 12: Separately or in-plane pulverize and disperse the pre-dye that develops color into fine particles using a pulverizer, mix with a binder, pigment, etc., and add Tanigaki additives as necessary. Especially to lubricate the coating fluid.

Examples of binders include starches, hydroxyethyl cellulose, methyl cellulose, polyvinyl alcohol,
Water-soluble binders such as styrene-maleic anhydride co-M@, styrene-butadiene copolymer, polyacrylamide, carboxymethylcellulose, gum arabic, and casein, and latexes such as styrene-butadiene latex can be used.

Examples of pigments include aluminum hydroxide, N-based and light calcium carbonate, zinc oxide, titanium oxide, barium sulfate, silica gel, activated clay, Merck, clay, satin white, kaolinite, calcined kaolinite, diatomaceous earth, and synthetic kaolinite. Examples include night, polyolefin particles, polystyrene particles, urea-formalin resin particles, and the like.

Next, regarding the material forming the overcoat layer in the present invention, water-soluble polymer compounds are generally preferred;
Among these, alginates alone or those in which alginates are essential and are used in combination with one or more polymeric compounds selected from hydroxyethyl cellulose, methyl cellulose, carboxymethyl cellulose, and polyvinyl alcoholic acid are preferable. (Japanese Patent Application No. 56-152455) The silicone rubber that is a feature of the present invention is mainly composed of chain diorganopolysiloxane, and has (OH,) 4 (OH) 31 (J, ,z,,(□H,
)s 810”/” (OH*=OH) (OH meeting) 811/ms(., Hl)4 (OH)S 10
Usually has a degree of polymerization of about 3,000 to 10,000
There are methyl silicone raw rubber, methylphenyl silicone raw rubber, methyl vinyl silicone raw rubber,
Generally commercially available products such as methylphenyl silicone raw rubber can be used.In addition, oil-strengthening agents such as finely powdered silica, calcium carbonate, alumina, titanium white, calcium silica, and zinc white, and acetyl Crosslinking agents such as silanes, ketoxime compounds, silazane, amide compounds, aminoxy compounds, titanium compounds, etc., and curing rate regulators such as gold with 4≦organic acid terms,
Complete sets with added corrosion inhibitors etc. can also be used ◇In addition,
In the present invention, the amount of silicone rubber added is 0.5% by weight or more, preferably 1 to 40% by weight, which is favorable from the viewpoint of surface characteristics, color development sensitivity, and printability. This is because if the amount added is less than 0.5% by weight, there is a tendency that the effect of preventing blocking and preventing abnormal gloss cannot be obtained. Also, 40! If the amount exceeds 100%, the rubber elasticity of the overcoat film will increase, so when finishing the Super Fist Calendar, 1,7'! The particles do not come off, the adhesion with the heat-generating head cannot be obtained, and the color development sensitivity and printability tend to deteriorate. ◇Furthermore, water resistant agents, water repellents, antifoaming agents, and ultraviolet resistant agents are preferable.

Further, in the present invention, the thickness of the overcoat layer as a dry film is 0.5 pm or more, preferably 3 to 12 μm.
is desirable in terms of chemical resistance and color development sensitivity.If the thickness of the 0 coating is thinner than 0.5 μm, the chemical resistance will not be sufficient;
If it exceeds 2 μm'i, the color development sensitivity tends to decrease.

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.

[Example 1] Solution A and Solution B. Solutions A and B were ground for 24 hours and 1 dJ in separate ball mills, fractionated, and a coating solution was prepared using the following formulation.

Coated IPJ manufactured by A was coated on base paper with a total basis weight of 481/m'' so that the coated amount after drying was 517 m1, and 1
After drying for 1 minute to make heat-sensitive recording paper, apply the 00 solution to a dry film thickness of 5 μmK using an overcodon and super-calender so that the Bekk smoothness is 400 seconds, and then overcoat. All thermal paper was made.

[Example 2] Solution D was used instead of O-Ki in Example 1, and the dry film thickness was 5.
#m was overcoated, and the Bekk smoothness was adjusted to approximately 400 seconds using a super calender, thereby producing a complete overcoated thermal paper.

[Comparison vll]

Using E (night) instead of liquid C in nj immersion test 1, overcoat to a dry film thickness of 5 μm, use a super calender to obtain Bekk smoothness of approximately 400 seconds,
By any chance, bar-coated thermal paper was produced.

[Example] 1fit chemical resistance test: The overcoated thermal paper of Example 1.2 and Comparative Example was
Optical 61 with Banafax UP-920 manufactured by Matsushita Denzo
After developing the color to 1f1.25, apply diazo photosensitive paper (developer RIO (JPY
After the paper was laminated with the paper immediately after the development process (SD), it was allowed to stand at room temperature for 3 minutes, and changes in the density of the background area and the color density (optical density) were shown.

Blocking property test: The overcoated thermal paper of Example 1.2 and Comparative Strength was colored to an optical density of 1.25 using a Matsushita Electric Power Co. Ltd. Paya Fax UP-920, and the surface (overcoated surface) was 10 layers stacked, 10kg load? Kake, 40
After being left at 90% R1H0 for 24 hours, each sheet was removed and the degree of peeling and layering on the smeared surface was observed.

Writability test: Letters and lines were drawn on the blank areas of the overcoated thermal papers of Example 1.2 and Comparative Example using commercially available Mitsubishi lead@98ooHB, and the writability was completely observed.

As a result, as shown in Table 3, the product of the present invention showed no image deterioration or background capri caused by the developer for diazo photosensitive paper, and had excellent writing properties without blocking. The comparative paper was not affected by the dye for diazo photosensitive paper, but it caused blocking, the pencil slipped, and characters and lines could not be drawn clearly enough. Regarding surface gloss, the non-inventive product was equivalent to or closer to Jinyu paper without overcoating, and no abnormal gloss was observed as in the comparative example.

Claims (1)

[Claims] A heat-sensitive coloring layer is provided, the main components of which are a colorless to light-colored dye precursor and a color developer that reacts with the dye precursor when heated, and furthermore, the heat-sensitive coloring layer has a high water solubility. In chemical-resistant heat-sensitive recording paper provided with an overcoat layer mainly composed of molecular compounds, K in the overcoat layer
Chemical-resistant thermosensitive recording paper with improved surface properties characterized by containing silicone rubber 02 Patent claims containing 0.5% by weight or more of silicone rubber in total with respect to the water-soluble polymer compound & Silicone rubber Contains 1 to 40i amount%