JP2956518B2 - Colored sheet for pressure-sensitive copying - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color developing sheet for pressure-sensitive copying having improved water resistance and scratch resistance.

[0002]

2. Description of the Related Art A pressure-sensitive copying paper is prepared by dissolving an electron-donating organic color-forming agent or the like in oil and encapsulating the oil droplets. When a large number of copies are required, the upper paper and the lower paper coated with a developer composition containing an electron-accepting developer that develops color when the surface of the support comes into contact with the above color former Is used in combination with a medium paper in which a developer composition is applied to the front surface and a color developing agent microcapsule composition is applied to the back surface. These upper, middle, and lower papers are usually used by combining them in the order of upper, lower, or upper, middle, and lower papers.The microcapsules are destroyed by writing pressure from above, pressure from a printer, etc. An oil in which an organic color developing agent or the like is dissolved is transferred to a color developing layer, and a color is formed by reacting with the color developing agent. Also known is a self-coloring pressure-sensitive copying paper in which a layer containing a color former and a color developer is provided on the same surface of a support.

[0003] Such pressure-sensitive copy paper has been widely used mainly as various slip sheets, and in recent years, pressure-sensitive copy paper has been widely used for delivery slips such as home delivery. Generally, a delivery slip is composed of several sheets of paper or film having a copying function, and at least one set of a slip including a destination display slip, a deposit slip, and a copy slip is attached to the package to be delivered. . However, if these delivery slips get wet in the rain or get wet during the handling process, they will break or the components of the color developing layer of the color developing sheet will be detached, leaving unknown information such as the destinations written. There was a problem.

Therefore, in order to impart water resistance, it has been practiced to cover and protect the delivery slip with a transparent plastic film. However, this method has a drawback that the design of the voucher is restricted and the number of vouchers increases, so that a plastic film or synthetic paper is used for the support of the pressure-sensitive copying paper constituting the voucher, and the strength and It is increasing that water resistance is imparted.

On the other hand, in a color developing sheet for pressure-sensitive copying,
Various starches as binders included in the color developing layer, polyvinyl alcohol, a water-soluble binder such as polyacrylic acid and a styrene-butadiene copolymer, a vinyl acetate copolymer,
Emulsions of acrylate polymers and the like are known. However, when a plastic film or synthetic paper is used for the support, the above-mentioned binders conventionally used do not provide sufficient water resistance, and also have poor scratch resistance due to poor binding with the support. There was a problem of poor sex.

Japanese Patent Application Laid-Open No. 62-113586 describes the use of a modified polyvinyl alcohol containing a silicon atom in the molecule for improving the water resistance and the use of a small amount of colloidal silica in combination. However, sufficient water resistance and scratch resistance have not been obtained, and no color developing sheet for pressure-sensitive copying having practically sufficient water resistance has yet been found.

[0007]

SUMMARY OF THE INVENTION The present invention has a sufficient color developing ability as a color developing sheet for pressure-sensitive copying, and is torn even when wet with water, or the color developing layer is detached to read a print. An object of the present invention is to provide a pressure-sensitive copying color developing sheet having excellent water resistance which does not make the color image impossible and having improved scratch resistance.

[0008]

Means for Solving the Problems As a result of extensive studies, the present inventors have developed a pressure-sensitive copying color developing sheet using a plastic film or synthetic paper as a support.
The above problem was solved by including colloidal silker having an average particle size of less than 10 nm as a binder in the color developing layer.

That is, the present invention provides a pressure-sensitive copying color developing sheet comprising a support and a developing layer containing an electron-accepting color developing agent, wherein the support is a plastic film or synthetic paper; And a color developing sheet for pressure-sensitive copying, wherein the color developing layer contains colloidal silker having an average particle diameter of less than 10 nm as a binder. Hereinafter, the present invention will be described in detail.

In the present invention, colloidal silica having an average particle size of less than 10 nm is used as a binder. Colloidal silica is a colloidal solution in which water is used as a dispersion medium and ultra-fine particles of silicic anhydride are dispersed in water. What is generally treated as a colloidal solution has a particle size of 1 nm to 100 nm as a dispersoid. It has been. Colloidal silica having an average particle size of less than 10 nm can be used in the present invention. When the average particle size is larger than 10 nm, the binding strength is deteriorated and the function as a binder is poor. In the present invention, since sufficient binding strength is obtained by using colloidal silica having an average particle size of less than 10 nm, a strong color developing layer is formed. The blending ratio of colloidal silica in the color developing layer is 10 to 50% by weight, more preferably 20 to 40% by weight of the color developing layer.

Further, in the present invention, colloidal silica,
Other conventionally used binders such as starch, sodium alginate, gum arabic, dextrin, glue, gelatin, casein, collagen, viscose, methylcellulose, ethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, polyvinyl alcohol, etc. It is also possible to use a molecule together with a vinyl acetate emulsion, an acrylic emulsion, a styrene-acryl copolymer emulsion, a styrene-butadiene copolymer emulsion or the like.

In the present invention, by using a plastic film or synthetic paper as the support, it is possible to obtain a strength that does not break even when it is wet with rain or water as compared with paper. Examples of the plastic film include a polypropylene film, a polycarbonate film, a triacetate film, and a polyester film. In addition, synthetic paper makes plastic film opaque,
Means that have been given writability and printability. These plastic fills or synthetic papers are pre-coated with corona or resin to improve adhesion.
Ordinary easy adhesion treatment may be performed.

The electron-accepting color developer contained in the color-developing layer of the present invention can be selected from those usually used in the field of pressure-sensitive recording paper. Examples thereof include acid clay, activated clay, attapulgite and the like. And an inorganic developer, such as phenol-formaldehyde resin, a polyvalent metal salt of a salicylic acid derivative, a polyvalent metal salt of a terpene phenol resin, and an organic developer such as a polyvalent metal salt of a salicylic acid-containing copolymer. It is not limited to these. However, when an inorganic color developer such as activated clay is used, a phenomenon in which a color image is temporarily lost when wet with water is observed. Therefore, it is more preferable to use an organic color developer.

Further, in the color developing layer of the present invention, if necessary, various additives commonly used in a color developing sheet for pressure-sensitive copying can be used, if necessary. Specifically, pigments such as calcium carbonate, magnesium carbonate, zinc oxide, titanium oxide, magnesium oxide, aluminum hydroxide, zinc hydroxide, kaolin, calcined kaolin, silica, barium sulfate, magnesium silicate, aluminum silicate, talc, etc. Inorganic pigments, polystyrene, organic pigments such as urea formalin resin, as well as other additives water-resistant agent,
Antioxidants, lubricants, fluorescent dyes and the like can also be used.

[0015] The method for preparing the coating solution of the color developing layer composition is not particularly limited, and is appropriately prepared. The application of the coating liquid is performed by a coater, and a coater appropriately selected from known coaters such as an air knife coater, a blade coater, a curtain coater, a rod coater, and a roll coater can be used. Coating amount is ^{2 to} 10 g / m ²
A range of degrees is appropriate.

[0016]

The reasons why the water resistance and scratch resistance are improved in the present invention are not clear, but are considered as follows. Colloidal silica having an average particle size of less than 10 nm used in the present invention is excellent in water resistance, has better binding properties than those having a large average particle size, and contributes to the formation of a color developing layer firmly. Therefore, the water resistance and the binding property are improved, and the detachment of the components of the color developing layer due to the wetting with water can be prevented. In addition, since the binding property between the color developing layer and the support is increased, the scratch resistance is improved.

[0017]

EXAMPLES The present invention will be described below in detail with reference to examples, but the present invention is not limited to these examples.
The parts and percentages shown below represent parts by weight and percentage by weight, respectively.

Example 1 Zinc 3,5-di (α-methylbenzyl) salicylate was uniformly dispersed by a sand grinder to obtain a dispersion having an average particle diameter of 2 μm and a concentration of 30%. Separately, a dispersion was prepared by dispersing 100 parts of calcium carbonate in 100 parts of a 0.5% aqueous solution of sodium acrylate, and 30% dispersion of the previously prepared zinc salt of 3,5-di (α-methylbenzyl) salicylate was prepared. 30 parts of a liquid, colloidal silica having an average particle diameter of 5 nm (trade name: Snowtex ST-XS, Nissan Chemical Co., Ltd.) as a dry solid content of 5 parts
0 parts, polyvinyl alcohol (trade name: PVA110,
100 parts of a 10% aqueous solution of Kuraray Co., Ltd. was mixed to obtain a coating solution. The obtained coating liquid is applied to a polyester-based synthetic paper (trade name: Crisper 2311, 50μ, Toyobo Co., Ltd.) with an air knife coater so that the solid content becomes 5 g / m ^2, and dried for pressure-sensitive copying. A developer sheet was obtained.

Example 2 The average particle diameter of Example 1 was 5 nm.
Colloidal silica (trade name: Snowtex ST-X)
S, Nissan Chemical Co., Ltd.) was changed to colloidal silica having an average particle diameter of 8 nm (trade name: Snowtex ST-S, Nissan Chemical Co., Ltd.) in the same manner as in Example 1 except for the color development for pressure-sensitive copying. I got a sheet.

Example 3 Zinc 3,5-di (α-methylbenzyl) salicylate was uniformly dispersed by a sand grinder to obtain a dispersion having an average particle diameter of 2 μm and a concentration of 30%. Separately, a dispersion was prepared by dispersing 100 parts of calcium carbonate in 100 parts of a 0.5% aqueous solution of sodium acrylate, and 30 parts of a 30% dispersion of zinc 3,5-di (α-methylbenzyl) salicylate was added thereto. , A colloidal silica having an average particle diameter of 5 nm (trade name: Snowtex ST-X)
S, Nissan Chemical Co., Ltd.) in a dry solid content of 70 parts and carboxy-modified SBR (trade name: Nipol407F, Nippon Zeon Co., Ltd.) in a dry solid content of 15 parts were mixed to obtain a coating liquid. The obtained coating liquid is applied to a synthetic paper made of polypropylene (trade name: YUPO # 60, Oji Yuka Synthetic Paper Co., Ltd.) using an air knife coater so that the solid content becomes 5 g / m ^2, and dried. Thus, a color developing sheet for pressure-sensitive copying was obtained.

Example 4 Zinc 3,5-di (α-methylbenzyl) salicylate was uniformly dispersed by a sand grinder to obtain a dispersion having an average particle diameter of 2 μm and a concentration of 30%. Separately, a dispersion was prepared by dispersing 100 parts of calcium carbonate in 100 parts of a 0.5% aqueous solution of sodium acrylate, and 30% dispersion of the previously prepared zinc salt of 3,5-di (α-methylbenzyl) salicylate was prepared. 30 parts of the liquid, colloidal silica having an average particle diameter of 5 nm (trade name: Snowtex ST-XS, Nissan Chemical Co., Ltd.) as a dry solid content of 2 parts
0 parts and 20 parts of an acrylic emulsion (trade name: AE120, Japan Synthetic Rubber Co., Ltd.) as a dry solid content were mixed to obtain a coating liquid. The obtained coating liquid is applied to a polyester-based synthetic paper (trade name: Crisper 2311, 50μ, Toyobo Co., Ltd.) with an air knife coater so that the solid content becomes 5 g / m ^2, and dried for pressure-sensitive copying. A developer sheet was obtained.

Example 5 Water 15 containing 100 parts of activated clay (trade name: Shilton DR-1, Mizusawa Chemical Co., Ltd.) was added with 1 part of sodium hydroxide and 1 part of sodium hexametaphosphate.
0 parts, colloidal silica having an average particle diameter of 5 nm (trade name: Snowtex ST-XS, Nissan Chemical Co., Ltd.) as a dry solid content of 80 parts, carboxy-modified S
15 parts of BR (trade name: Nipol407F, Nippon Zeon Co., Ltd.) was mixed as a dry solid content to obtain a coating liquid. The obtained coating liquid is applied to a polyester synthetic paper (trade name: Crisper 2311, 50μ, Toyobo Co., Ltd.) with an air knife coater so that the solid content becomes 8 g / m ^2, and dried for pressure-sensitive copying. A developer sheet was obtained.

Example 6 Water 15 containing 100 parts of activated clay (trade name: Shilton DR-1, Mizusawa Chemical Co., Ltd.) was added with 1 part of sodium hydroxide and 1 part of sodium hexametaphosphate.
0 parts, and 30 parts of colloidal silica having an average particle diameter of 5 nm (trade name: Snowtex ST-XS, Nissan Chemical Co., Ltd.) as a dry solid content, and an acrylic emulsion (trade name: AE120, Nippon Synthetic Rubber) Co., Ltd.) as a dry solid content and 20 parts were mixed to obtain a coating liquid. The obtained coating liquid is applied to a polyester synthetic paper (trade name: Crisper 231)
1, 50 μm, Toyobo Co., Ltd.) with an air knife coater so that the solid content becomes g / m ^2, and dried to obtain a color-developed sheet for pressure-sensitive copying.

Comparative Example 1 The average particle diameter of Example 1 was 5 nm.
Colloidal silica (trade name: Snowtex ST-X)
S, Nissan Chemical Co., Ltd.) was changed to a colloidal silica having an average particle diameter of 14 nm (trade name: Snowtex 20, Nissan Chemical Co., Ltd.) in the same manner as in Example 1 to obtain a color-developed sheet for pressure-sensitive copying. Obtained.

[0025]

Comparative Example 2 The average particle size of Example 1 was 5 nm.
Colloidal silica (trade name: Snowtex ST-X)
S, Nissan Chemical Co., Ltd.) was changed to 50 parts as a dry solid content, and carboxy-modified SBR (trade name: Nipol407F, Nippon Zeon Co., Ltd.) was changed to 15 parts as a dry solid content. Thus, a color developing sheet for pressure-sensitive copying was obtained.

The developed sheets for pressure-sensitive copying obtained in the above Examples and Comparative Examples were evaluated as follows, and the results are shown in Table 1. [Test Method] (1) Coloring Density The obtained pressure-sensitive copying color developing sheet was superimposed on a commercially available upper paper (trade name: CCP NW40T, Nippon Paper Industries Co., Ltd.) so that the coated surface faced, and a line was drawn. After a calendering process at a pressure of 50 kg / cm, the color density after 24 hours was measured using a Macbeth densitometer (RD-914, Wratten # 106 filter, MA
(CBETH). (2) Water resistance Using an Adam Sweatlab tester, the turbidity of water after the treatment for 20 minutes was indicated by a transmittance at a wavelength of 622 nm using COLORIPET DK-II (manufactured by Shimadzu Corporation). (The larger the value, the better the water resistance.) (3) Scratch resistance A 250 g weight is applied to a ballpoint pen without ink to obtain a 3
The coating layer was moved at a speed of m / min, and the state of the coating layer at that time was visually determined. Coating layer remains ○ Coating layer is completely peeled off ×

[0028]

[Table 1]

As is clear from Table 1, in Examples 1 to 6 satisfying the requirements of the present invention, good quality was obtained in both water resistance and scratch resistance. This contrast, when the particle diameter of colloidal silica is greater (Comparative Example 1), etc.,
Water resistance and scratch resistance are very poor.

[0030]

The color-developing sheet for pressure-sensitive copying of the present invention has a sufficient color density and is excellent in water resistance, so that the color-developing layer components do not detach even when wet with water. ,
Because of its excellent scratch resistance, the color-developing layer does not fall off the support due to rubbing between papers or friction in the handling process. Therefore, when the color-developed sheet for pressure-sensitive copying of the present invention is used as a delivery slip sheet, a very useful delivery slip can be obtained without the information written during handling becoming unclear or unreadable.

Claims (3)

(57) [Claims] 1. A pressure-sensitive copying color developing sheet comprising a support and a color developing layer containing an electron-accepting color developing agent, wherein the support is a plastic film or synthetic paper, and the color developing is pressure-sensitive copying for color-developing sheet, characterized in that the average particle size including Koroidarushi Li Ka of less than 10nm as a layer is the binder. 2. The color-developing sheet for pressure-sensitive copying according to claim 1, wherein the electron-accepting color developer is an organic color developer. 3. The color-developing sheet for pressure-sensitive copying according to claim 1, wherein the content of colloidal silica in the color-developing layer is 10 to 50% by weight.