KR910009734B1 - Producing method of recording paper - Google Patents

Abstract

A single layer pressure-sensitive recording paper is produced by coating 5-15 g/m2 of a coating liquor (A) [20% concn. on the basic paper, coating 0.5-2 g/m2 of a surface-coating liquor (B) [5% concn. on the coated layer. The liquor (A) is composed of 10-40 wt.% colorless dyestuff-contg. capsule, 5-20 wt.% developer, 5-30 wt.% pigment, 5-20 wt.% binder and 5-30 wt.% buffer material, and the liquor (B) is composed of 1-3 wt.% polyvinyl alcohol, 3-5 wt.% starch and 0.3-0.6 wt.% glyoxane. The reocrding paper has an excellent developing velocity and concentration.

Description

Manufacturing method of single layer color developing pressure-sensitive recording paper

BRIEF DESCRIPTION OF THE DRAWINGS The single-layered structure diagram of the pressure-sensitive recording paper obtained by the present invention.

* Explanation of symbols for the main parts of the drawings

1: base paper 2: pressure-sensitive paper coating layer

3: surface coating layer

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for manufacturing a color development pressure-sensitive recording paper, and more particularly, to a method for manufacturing a single layer color development pressure-sensitive recording paper with improved friction contamination and natural color development. Single-layer pressure-sensitive recording paper is made by coating capsules and color developer with colorless dye on one side of the paper. In use, the capsule is destroyed when pressure is applied to the paper, and the colorless dye-containing dye reacts with the colorant. It will cause color development.

Most of the pressure-sensitive recording papers currently in practical use have a two-layer structure in which a capsule is coated on a base paper and a developer is coated on it.

This type of decompression recording paper has a disadvantage that the color development speed is low and the color development is low, and the cost rises due to two coatings in the production process.

In recent years, as the capsule manufacturing technology is advanced, so-called single layer color developing pressure-sensitive recording paper produced by one coating is being used.

Although the above-mentioned monolayer color decompression recording paper has the advantage that the color development speed and concentration are greatly improved, it causes new problems in quality such as contamination due to friction and natural color development. Especially, the discoloration phenomenon due to polar solvent or plasticizer is severe and the recorded contents are recorded. There is often an example that becomes unreadable.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing a single-layer color developing pressure-sensitive recording paper which solves the drawbacks seen in such a conventional single-layer pressure-sensitive recording paper.

Accordingly, the present invention is characterized by applying a surface coating liquid consisting of polyvinyl alcohol, starch and glyoxane after coating the colorless dye-containing capsule and the developer on a base paper.

The colorless dye-containing capsule used in the present invention is a capsule made by an interfacial polymerization method in which a phthalide derivative, a fluorane derivative and the like are dissolved in a high boiling hydrophobic solvent and encapsulated with urea or melamine resin.

In addition, as a colorant, an organic or inorganic acid material which is developed by reacting with the colorless dye is used. Specific examples of the organic acid materials include para-substituted phenol formaldehyde resins and metal-modified phenol formaldehyde resins. As inorganic acid materials, natural or semisynthetic inorganic solid acids such as activated clay and acid clay may be used.

Pigments used in the present invention are conventional pigments such as calcium carbonate, cray, talc and the like, and binders for adhering these capsules, colorants, and pigments to the base paper include natural or synthetic resin materials such as latex, polyvinyl alcohol, and starch. Can be used.

As other buffering additives, starch particles, cellulose and the like having a large particle size are added. The composition ratio of the substance in the present invention is as follows. All "%" used in the present invention refers to "% by weight".

Colorless dye-containing capsule 10-40% (solid content)

5-20% of developing agents (solid content)

Pigment 5-30% (solid content)

Binder 5-20% (solid content)

5 to 30% of cushioning material (solid content)

The composition of the above ingredients is adjusted to a concentration of 15 to 35%, and dried by coating 5-15 g / m 2 with an air knife or bar coater.

After coating, the base paper is dried, and then the surface coating liquid containing polyvinyl alcohol, starch and glyoxane as a heavy component is dried at a coating layer of 0.5-2 g / m 2 on the base paper coating layer. The component ratio of the surface coating solution is preferably 1 to 5% of polyvinyl alcohol, 0.5 to 5% of starch, and 0.1 to 0.9% of glyoxane.

More preferably, the component ratio of the above-described surface coating liquid is preferably 1 to 3% of polyvinyl alcohol, 3-5% of starch, and 0.3 to 0.6% of glyoxane. When the amount of polyvinyl added is less than 1%, friction, wet heat, and solvent resistance, which is an improvement effect of the present invention, are significantly lowered. When it exceeds 5%, wet heat and solvent resistance are improved, but the coating amount is increased due to viscosity increase. It rises (0.5-2g / m <2>), and color development worsens and a uniform coating film is not obtained, and it has a bad influence on friction contamination.

In addition, since glyoxane dosage is directly related to moist heat pollution and solvent resistance, when the glyoxane content is less than 0.1%, it adversely affects moist heat pollution and solvent resistance. The print settings may be delayed, causing print defects.

On the other hand, since the amount of starch is related to the binding strength of the coating layer and the fluidity of the composition liquid, when the amount of starch is added less than 0.5%, the binding force is weakened, so that picking problems that the coating layer falls off are likely to occur, and more than 5%. In this case, the fluidity of the composition liquid is remarkably deteriorated, which makes it impossible to obtain a uniform coating layer, and as a result, adversely affects friction contamination.

When the surface coating solution is coated, the viscosity is lowered and uniformly coated using a roll or an air knife.

The monolayer color developing pressure-sensitive recording paper thus prepared is not easily colored or spontaneously colored by friction as the surface coating solution layer is coated on the coating layer, and the color is not discolored by the polar solvent or the vinyl chloride film.

Hereinafter, the present invention will be described in detail by way of examples.

EXAMPLE

(Color development and developer coating process)

25% capsule (solid)

Organic developer 15% (solid content)

Calcium Carbonate 25% (solid content)

Latex 10% (solid content)

5% starch (solid)

20% of buffer materials (solid content)

A coating solution added with a trace amount of a dispersant and an antifoaming agent is prepared at a concentration of 20%, and coated with 5-15 g / m 2 on a paper using an air knife coater and dried.

(Surface Coating Solution Coating Process)

Polyvinyl alcohol 2% (solid content)

5% starch (solid)

Glyoxane 0.5% (solid content)

The surface coating solution obtained by preparing the composition at a concentration of 5% was coated at 0.5 to 2 g / m 2 on the coated layer of the paper which had been subjected to the above step using an air knife coater, and then dried again, as shown in the drawing. A pressure-sensitive paper coating layer 2 is coated on the film, and a pressure-sensitive recording paper having a single layer structure whose upper surface is protected by the surface coating layer 3 is obtained.

Comparative Example 1

(Primary coating)

56% capsule (solid)

Latex 5% (solid content)

10% starch (solid)

29% of buffer materials (solid content)

The composition is prepared in a 30% aqueous solution, which is then coated with 3-4 g / m 2 on an original paper with an air knife coater and dried.

(The second coating)

Organic developer 25% (solid content)

Calcium Carbonate 50% (solid content)

Cray 10% (solid content)

Latex 8% (solid content)

5% starch (solid)

Dispersant and Water Resistant 12% (Solid)

The composition is prepared in a 30% aqueous solution, coated with a bar coater on a coating layer of 3-4 g / m 2 on a primary coated base paper, and dried to obtain a pressure-sensitive paper having a two-layer structure.

Comparative Example 2

30% capsule (solid)

10% of developing colorants (solid content)

20% calcium carbonate (solid content)

Latex 10% (solid content)

10% starch (solid)

Buffer and Dispersant 20% (Solid)

The composition was prepared by 30% aqueous solution and coated with 7 g / m 2 of an air knife coater and dried to obtain a single-layer pressure-sensitive recording paper. Comparative Example 1 is a conventional two-layer pressure-sensitive recording paper, even if no further explanation. It will be appreciated that Example 2 is an improved single layer pressure sensitive recording sheet.

Each of the pressure-sensitive recording papers obtained through the above-described Examples and Comparative Examples 1 and 2 was subjected to quality evaluation for each of the following items.

1) Color performance: Place a 45g / m² section of paper on a self-coloring pressure-sensitive paper, pass it through a super calender (200㎏ / ㎝) to develop color, and measure it with a colorimeter.

2) Friction fouling: Cut 2 sheets of 5 × 20㎝ and apply 1㎏ of pressure to the upper surface, fix 1 sheet, and measure the contamination caused by tensioning one sheet.

3) Moisture and heat resistance: Put the self-decomposable pressure-sensitive recording paper in a constant temperature and humidity chamber at 50 ° C and 95% relative humidity (RH), and store it for 10 hours.

4) Color Resistant Solvent: After developing the pressure-sensitive recording paper, adhere it to the vinyl chloride film, cover it with a glass plate, and store it in a dark place at 60 ℃ for 8 hours, and then measure the color development.

The results of the above quality evaluation are shown in the following table.

TABLE 1

○: Excellent ▲: Normal ×: Poor

As can be seen from the table, the pressure-sensitive recording paper of the present invention appears to be superior in quality.

The pressure-sensitive recording paper obtained according to the present invention as described above is protected by the coating liquid layer of the pressure-sensitive paper due to the surface coating solution applied on the coating layer, thereby significantly reducing frictional and spontaneous color staining, and contacting the polar solvent or the vinyl chloride film. It does not discolor, and even under wet heat conditions, there is very little deterioration or dimensional deformation, so that it can be stored for a long time and its color development rate and concentration are superior even though it is applied in a small amount. .

Claims (1)

In the method for producing a self-chromic pressure-sensitive paper, which is carried out by applying a pressure-sensitive paper coating liquid consisting of a colorless dye capsule, a developer, a pigment, a latex, a starch, a buffer material, and the like onto a base paper, application and drying of the pressure-sensitive paper coating liquid Then, 1-3 weight% of polyvinyl alcohol is on the upper surface of this coating layer. The surface coating solution containing 3 to 5% by weight of starch and 0.3 to 0.6% by weight of glyoxane is coated with a coating amount of 0.5 to 2 g / m 2 using a conventional air knife coater. Manufacturing method.

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