JPH0311915B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a hard hot-melt carbon layer on at least a portion of a hot-melt release layer formed on a base sheet, and has excellent stain resistance and pressure- and heat-sensitivity. Concerning carbon copy paper.

Pressure-sensitive copying paper with a hot-melt carbon ink layer, which has been widely used in the past, contains a relatively large amount of mineral oil (approximately 20 to 50% by weight) in the carbon layer, so the layer is soft and can be used on hands, clothes, etc. Although various attempts have been made to overcome these drawbacks, none have yet been found to be fully satisfactory.

For example, the wax-type carbon ink disclosed in Japanese Patent Application Laid-Open No. 52-2609 has excellent copyability, but is insufficient in stain resistance, particularly in the stain resistance of copied prints. The problem of print stain resistance has come into focus with the spread of OCR (optical character reading), and the problem of misreading or refusal of reading by OCR devices due to print stains (tailing due to rubbing) has not been resolved in this field. This has become an important issue to be addressed.

On the other hand, thermal transfer paper, which is made by providing a carbon ink layer that does not contain oil or contains a relatively small amount of oil, on thin paper with low permeability (condenser paper, copy paper, etc.) should have sufficient stain resistance for printing. However, because the carbon layer is strongly adhered to the paper, peeling and transfer properties are poor, and not only does extra heat be required during thermal transfer, but also unpleasant noises occur when the transfer paper and receiving paper are peeled off after transfer. There are some drawbacks such as emitting .

In view of this situation, the inventors of the present invention have made extensive studies and found that a hot melt type release layer containing a surfactant is further free from oil.
The present invention was completed by discovering that by providing a hot-melt type carbon layer containing a relatively small amount, all of the above-mentioned drawbacks of pressure-sensitive copying paper and pressure-sensitive transfer paper can be solved at once.

That is, the gist of the present invention is that nonionic surfactants 5 to
50% by weight, 30-70% by weight of waxes and 0 pigments
~40% by weight of waxes, 30~98% by weight of pigments and/or dyes 2 on at least a portion of the hot melt type release layer formed on the base sheet.
The present invention is a pressure-sensitive and heat-sensitive carbon copying paper on which a hot-melt type carbon layer containing up to 40% by weight of oil and 0 to 20% of oil is formed.

Hereinafter, the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view showing a part of a two-sheet copy slip suitable for OMR (optical mark reading).

FIG. 2 is a schematic sectional view showing a part of carbon copying paper using imitation paper as a base sheet.

The base sheets 1 and 1' used in the present invention are not particularly limited, but paper is usually used. In addition, plastic film, synthetic paper, etc. may be used as appropriate.

A suitable nonionic surfactant to be added to the hot-melt release layers 2 and 2' is a nonionic surfactant that is liquid at about 50°C or below. Waxes tend to sweat between the crystal lattices and promote layer separation.

Nonionic surfactants that can be used in the present invention include polyoxyethylene alkyne ether, polyoxyethylene alkyne phenyl ether, polyethylene glycol alkyl ester, polyoxyethylene alkyne amine, polyoxyethylene sorbitan alkyne ester, sorbitan alkyl ester, polyoxy Examples include ethylene polyphenyl ether, polyoxyethylene castor oil ether, polyoxyethylene alkynamide, and Pluronic or Tetronic type nonionic surfactants.

In addition, polyols such as polyethylene glycol, polypropylene glycol, glycerin, polyglycerin, and their ethylene oxide adducts may be used in place of some of these nonionic surfactants.

The nonionic surfactant in the hot-melt release layer is compatible with waxes when heated and molten, but during the cooling and solidification stage after thermal application, layer separation occurs and the hydrophilic groups are directed toward the paper surface to become lipophilic. Because the groups are aligned toward the wax, the surface of the release layer becomes a wax slouch, making it harder and improving stain resistance.At the same time, the transferability of the release layer is improved due to the wax's moderate adhesion to the paper surface. considered to be a thing.

The blending amount of the nonionic surfactant is 5 to 50% by weight, preferably 5 to 20% by weight based on the total weight of the ink.
If it is less than 5% by weight, it will not produce a sufficient release effect as a release layer (however, if polyols and their ethylene oxide adducts are used as part of a nonionic surfactant, even about 2% by weight will be effective). ), and if it exceeds 50% by weight, the release layer itself becomes too soft, causing contamination.

The waxes added to the hot-melt release layers 2 and 2' or the hot-melt carbon layers 3 and 3' are wax-like substances with a melting point of about 40 to 120°C.
Particularly useful are esters, ketones, imides, paraffins, polyethylene, fatty acids, etc., such as carnauba wax, montan wax, auricule wax, coconut wax, sugarcane wax, rice wax,
Wood wax, oxidized micro wax, stearon, palmitone, stearimide, stearamide, paraffin wax, polyethylene wax, stearic acid, behenic acid, palmitic acid, Hoechst wax (O, OP, S, etc.), Varico wax (WB-5, WB-17, etc.).

The waxes for the release layer and the waxes for the carbon layer may be the same or different.

The amount of waxes added is 30 to 70 in the release layer.
% by weight, and in the carbon layer it is 30 to 98% by weight. In the former case, if it is less than 30% by weight, the ink will become soft and cause contamination, and if it is less than 70% by weight,
If it exceeds this, the release layer itself becomes hard and a sufficient release effect cannot be obtained. On the other hand, in the case of the latter, if it is less than 30% by weight, the fluidity of the ink will be poor and the printed surface will not be finished smoothly, causing stains.
Above this amount, at least 2% of the colorant is required.

In addition to the above-mentioned surfactants and waxes, pigments may be added to the release layer to improve ink tone, ink receptivity, copyability, etc., but the amount added should be limited to 40% by weight or less. If it exceeds 40% by weight, the fluidity of the ink will deteriorate and the printed surface will not be finished smoothly.

When the release layer is transparent, it is not necessary to specifically blend the pigment, but a transparent extender pigment may be used to improve the ink receptivity of the carbon layer.

Examples of extender pigments include clay, kaolin, calcium carbonate, aluminum hydroxide, alumina white, and white gloss.

In addition, when a carbon layer is partially provided on the release layer, a colored pigment of a color different from that of the carbon layer, such as a black pigment (carbon black, iron black, etc.), an indigo pigment (dark blue, ultramarine blue, cyanine blue,
alkali blue, etc.), red pigments (lake red, etc.), red pigments (lake red, etc.),
By appropriately using carmines, etc.) and white pigments (titanium dioxide, zinc oxide, etc.), it is possible to obtain multicolor copying paper.

In addition to the above ingredients, the hot-melt release layer contains conventional additives such as pigment dispersants (lecithin, etc.),
A pigment anti-settling agent (such as bentonite) may be appropriately blended.

The hot-melt release layer ink prepared from the above ingredients is coated or printed onto a base sheet using a conventional coater or printer equipped with a heating device. The amount of inking is usually about 2 to 5 g/m ² .

In the copying paper according to the present invention, hot-melt carbon layers 3 and 3' are further provided on at least a portion of the hot-melt release layer formed on the base sheet as described above.

The carbon layers 3 and 3' contain 30 to 98% by weight of wax as described above, as well as pigments and/or pigments.
Or add dye.

Pigments are appropriately selected from those listed above, and dyes are appropriately selected from oil-soluble dyes, such as basic dye bases such as methyl violet base, Victoria blue base, rhodamine red base, etc., and each is used alone or in combination. do.

The amount of pigments and/or dyes usually ranges from 2 to 40
If it exceeds 40% by weight, the fluidity of the ink will deteriorate and the printed surface will not be finished smoothly.

If desired, oil, such as mineral oil, especially a lubricating oil with a viscosity of 70 to 300 centistokes, may be added to the carbon layer, but the amount should be kept within 20% by weight, and should not exceed 20% by weight. This is not preferable because the stain resistance decreases.

Note that even if no oil is added to the carbon layer, it is possible to make approximately 5 to 6 copies under normal usage conditions.

Furthermore, other conventional additives, such as pigment dispersants (lecithin, etc.), stain preventive agents (various resins, ethyl cellulose, ethylene-vinyl acetate copolymer resin, etc.), etc., may be appropriately blended into the hot-melt carbon layer, if desired. It's okay.

The hot-melt carbon layer ink prepared from the above ingredients is coated or printed on at least a portion of the release layer using a conventional coating machine or printing machine equipped with a heating device (the amount of ink applied is usually about approx. 2-5 g/ ^m2 ). In this case, the ink for the release layer is melted at about 90 to 120°C and immediately solidified and set immediately after being applied, so after forming the release layer on the base sheet, the carbon layer is subsequently applied to the release layer. The layer can be coated or printed on.

The copying paper according to the present invention has the advantages of conventional pressure-sensitive copying paper and thermal transfer paper without the disadvantages of conventional pressure-sensitive copying paper and thermal transfer paper, that is, moderate peeling transfer properties and excellent stain resistance, especially stain resistance for printing, so it is highly sensitive. It is suitable for both pressure copying paper and thermal transfer paper.

Hereinafter, the present invention will be explained with reference to Examples. In the examples, "parts" means "parts by weight."

Example 1 5 parts of Lake Red C, 25 parts of aluminum hydroxide and 30 parts of Nonion 0-2 (polyoxyethylene monooleate manufactured by NOF Corporation) were mixed,
After kneading the meat using three rolls, it is added to heated and melted wax (10 parts carnauba wax and 20 parts paraffin wax), and then put in a homomixer while keeping it at 100°C to create a uniform flow of drop-out color. A release layer ink was prepared.

Heat-melted wax (paraffin wax 40
25 parts of Montan wax, 15 parts of Carnauba wax) and 5 parts of EVAFLEX 210 (ethylene-vinyl acetate copolymer manufactured by Mitsui Polychemical Co., Ltd.) were mixed with 15 parts of carbon black and heated. Use a roll to thoroughly knead the meat.
Carbon ink for OMR reading was prepared.

The above ink for the release layer is printed on the copy paper 1 using a heating flexo printing machine, and the carbon ink for OMR reading is printed on a predetermined portion of the release layer 2 using a heating flexo printing machine to form a carbon layer. By forming No. 3, a carbon copying paper for OMR with excellent copyability and abrasion resistance was obtained (see Fig. 1).

In the embodiment shown in FIG. 1, the raked C is
The print on OMR paper 4 drops out because it is a drop-out color that cannot be read by an OMR machine, and the black carbon print can be read by an OMR machine, and even if you rub it with your finger, this print will not leave any traces. It did not occur.

Example 2 10 parts of calcium carbonate, 25 parts of titanium dioxide and 25 parts of polypropylene glycol were mixed,
After kneading the meat using this roll, it is added to heated and melted wax (5 parts of carnauba wax, 30 parts of paraffin wax and 5 parts of Kist OP wax), and kept at 100°C in a homomixer to achieve uniform fluidity. An ink for a release layer was prepared.

Heat-melted wax (carnauba wax 10)
20 parts of navy blue, 30 parts of calcium carbonate, and 5 parts of hydrogenated castor oil were added to 2 parts of ethyl cellulose and 30 parts of paraffin wax (30 parts of paraffin wax, 3 parts of polyethylene wax) and 2 parts of ethyl cellulose. After mixing, the mixture was thoroughly kneaded using three heated rolls. An ink for a uniformly fluid carbon layer was prepared.

The above ink for the release layer is printed on imitation paper 1' using a heated flexographic printing machine, and the above ink for the carbon layer is printed on the printed release layer 2' using a heated flexographic printing machine to form a carbon layer. By forming carbon copying paper 3', a carbon copying paper with excellent copyability and abrasion resistance was obtained (see FIG. 2).

In general, imitation paper is more transparent and oil-absorbing than copy paper, so if left as is, the carbon ink will seep through, resulting in poor copyability and poor print contrast due to the gaps, making it unsuitable as carbon copy paper. However, in the embodiment shown in FIG. 2, the release layer 2' not only provides release properties to the carbon layer 3', but also provides whiteness and opacity to the imitation paper 1', so there is no such problem.

Example 3 50 parts of stearic acid, 25 parts of rice wax, and 25 parts of Hylic AQ-120 (polyoxyethylene castor oil ether manufactured by Ito Oil Co., Ltd.) were heated and melted, and mixed thoroughly using a homomixer while maintaining the temperature at 100°C. A uniformly fluid release layer ink was prepared.

Heat-melted wax (paraffin wax 45)
15 parts of carbon black were added to 5 parts of Alcon P-90 (aliphatic hydrocarbon resin manufactured by Arakawa Chemical Co., Ltd.), 5 parts of EVAFLEX-210, and heated. The mixture was sufficiently kneaded to prepare an ink for a uniformly fluid carbon layer.

Excellent abrasion resistance is achieved by printing the above release layer ink on transfer paper using a heated flexographic printing machine, and then printing the above carbon layer ink on the printed release layer using a heated flexographic printing machine. A thermal transfer paper was obtained.

When the obtained thermal transfer paper was placed on a cloth, paper, film, etc. and heated from above, the ink layer was completely peeled off from the transfer paper and transferred to the cloth, paper, film, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view showing a part of a two-copy slip suitable for OMR. FIG. 2 is a schematic sectional view showing a part of carbon copying paper using imitation paper as a base sheet. 1 is the base sheet (copy paper), 2 is the release layer (red), 3 is the carbon layer (black), 4 is OMR paper,
1' is a base sheet (imitation paper), 2' is a release layer (white), and 3' is a carbon layer (black).

Claims (1)

[Scope of Claims] 1. At least on a hot-melt release layer formed on a base sheet containing 5 to 50% by weight of a nonionic surfactant, 30 to 70% by weight of a wax, and 0 to 40% by weight of a pigment. A pressure-sensitive heat-sensitive carbon copying paper on which a hot-melt carbon layer containing 30 to 98% by weight of waxes, 2 to 40% by weight of pigments and/or dyes, and 0 to 20% by weight of oil is formed. 2. The pressure-sensitive and heat-sensitive carbon copying paper according to item 1, wherein the surfactant is a nonionic surfactant that is liquid at 50° C. or lower.