JPH0482790A - Wax type receiving paper - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an image receiving paper made of a porous sheet.

[Conventional technology and its problems]

Conventionally, thermal transfer methods have come to be widely used as a simple image forming method. This thermal transfer method can be roughly divided into sublimation transfer type and wax type.

In the wax type, a wax ink layer that softens with heat is provided on a base sheet such as a polyester film, and a thermal head heats the ink layer from the back in an image-like manner to transfer the ink layer to the transfer material to form the desired image. This is a method to do so.

In the case of this wax type, the wax layer is transferred as is during transfer, so it can be transferred to ordinary paper, and it also has the advantage of being able to form images with excellent light resistance because pigments can be used as the coloring agent. .

Because of these advantages, it is widely used in printers such as word processors, personal computers, and facsimile machines.Furthermore, because of its ease of printing, its use has expanded to include printing in small lofts, such as creating barcode labels, cards, etc. It has been done.

In addition, in fields that require such performance, plastic films are used as the base material for image-receiving sheets. Since these are made of plastic film, it is difficult to write on them using these writing instruments.

As a method for solving the above-mentioned problems, a method is known in which a porous image-receiving layer made of inorganic or organic particles and a binder is formed on the surface of a base sheet (for example, Japanese Patent Laid-Open No. 61-284486 , No. 217289, No. 1273
No. 90, Publication No. 8385, etc.).

However, in the case of these conventional image receiving sheets,
If the amount of particles is increased to improve porosity, there is a problem that the strength of the porous layer is insufficient and the particles will fall off even with a weak friction force, making the paper brittle and difficult to manipulate when folding or folding. I'm not satisfied.

On the other hand, polyurethane porous sheets can be produced by wet method, dry method,
It is manufactured by various methods such as chemical foaming method and extraction method (for example, Japanese Patent Publication No. 63-5425, Japanese Patent Publication No. 63-34).
No. 835), it is used as synthetic leather, etc.
There is no example of it being used as a receiving paper.

An object of the present invention is to economically provide image-receiving paper that is writable, has good ink fixing properties, and can be folded.

[Means to solve the problem]

The image-receiving paper of the present invention is a porous sheet formed by providing a porous layer (hereinafter referred to as "porous hydrophobic polyurethane layer") made of hydrophobic polyurethane on a support.

Examples of the base material used in the present invention include plastics,
Examples include paper and synthetic paper, with plastic and paper being particularly preferred. Specific examples of plastic films include films of polypropylene, cellophane, polycarbonate, cellulose acetate, polyethylene, polyester, polyvinylidene chloride, polyvinyl alcohol, fluororesin, chlorinated rubber, ionomer, etc., or composites thereof. The thickness of the support is preferably 2 to 200μ, although it may be changed as appropriate depending on its strength and purpose of use.
It is m.

In order to improve the adhesion with the image-receiving layer, a primer layer is applied to the above support in advance using polyurethane resin, polyvinyl butyral resin alone or in combination with a crosslinking agent, or an alloy of vinyl chloride vinyl acetate copolymer and polyester resin. may be painted. (Figure 2) Examples of the hydrophobic polyurethane used in the present invention include:
Examples include polyether polyurethane and polyester polyurethane, with polyether polyurethane being particularly preferred.

The method for forming a porous hydrophobic polyurethane layer is as follows:
Various methods can be adopted, but in particular hydrophobic polyurethane,
Preferred is a method using a water-in-oil polyurethane emulsion consisting of a surfactant (eg, a hydrophilic polyurethane), an organic solvent, and water. The emulsion itself is obtained by emulsifying water in an organic solvent solution or dispersion of hydrophobic polyurethane using a surfactant (e.g., hydrophilic polyurethane). It is well known in publications, etc., and various products are commercially available as air permeability prevention treatment agents for clothing, etc., and any of them can be used in the present invention.

After coating the above emulsion onto the base material l (see Figure 1) using any coating means, the organic solvent in the emulsion is applied at a relatively low temperature, e.g.
The emulsion is gelled by evaporation at 50-80°C, and then porous is formed by drying the water at temperatures above 100°C.

In the thermal transfer sheet of the present invention, the thickness of the porous hydrophobic polyurethane layer is preferably 3 to 50 μm, more preferably 3 to 20 μm. If the thickness is 30 μm or more, the elasticity may be too strong and the writing properties may be poor.

To make the thickness of the core layer within the above-mentioned preferred range, for example, gravure coating, blade cord, triple reverse coating,
Coating means such as comma coat may be used.

Further, in the image receiving paper of the present invention, the moisture permeability of the porous hydrophobic polyurethane layer alone is preferably 1000 to 900.
It is 0 g/(bo・h). The moisture permeability is 1000g/
If it is less than (rrf·h), there is a risk of insufficient writability, and if it exceeds 9000 g/(rd·h), the strength may be insufficient, and the porous layer may be destroyed by friction, for example.

In addition, when forming a porous layer, a suitable crosslinking agent such as polyisocyanate, methylol compound, epoxy compound,
A porous layer with excellent scratch resistance can be formed by using a known crosslinking agent such as polyamine, melamine resin, or glyoxal resin. In addition, one or more suitable additives may be added depending on the purpose.

〔Example〕

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples, but these Examples are not intended to limit the scope of the present invention in any way.

Example 1 A polyethylene terephthalate film (thickness 50 μm) was used as a base material, and 100 parts W1 of a 30% methyl ethyl ketone solution of a polyether polyurethane resin as a material for forming a porous layer.
Type 0 emulsifier 5 parts methyl ethyl ketone 30 parts toluene
30 parts water
60 parts 50% methyl ethyl ketone solution of polyisocyanate 10 parts After applying the above porous layer forming material by gravure coating, the organic solvent in the emulsion was evaporated at 60°C for 12 minutes, and then 125
It was dried for 2 minutes at 40° C. and aged for 1 week at 40° C. to produce a thermal transfer sheet.

The image-receiving paper thus obtained had a porous hydrophobic polyurethane layer with a thickness of about 15 μm, and had a good appearance with no pinholes and very few streaks or voids.

Carefully peel off the above porous layer from the base material and JISL 1
When the moisture permeability was measured according to the 099A-1 method, the moisture permeability was 6452 g/(%·h).

Example 2 A porous hydrophobic polyurethane layer having a thickness of approximately 5 μm was formed in the same manner as in Example 1 on paper having a basis weight of 350 g/r&.

Next, writing was performed using a pencil or a water-based pen, and the writing properties were good.

Example 3 Polyethylene terephthalate film (thickness 75 μm)
A porous hydrophobic polyurethane layer having a thickness of about 4 μm was formed in the same manner as in Example 1 by corona-treating the surface of the sample. The writability was good.

Usage example Polyolefin wax 10 parts Carbon black 2 parts Water
10 parts isopropyl alcohol 10 parts W10 emulsifier
A thermal transfer sheet was prepared by applying 0.1 part of the above-mentioned coating composition onto the surface of a 6.0 μm thick polyester film at a drying rate of 2 g/1rd and drying.

Using the image receiving paper of the above example and the above thermal transfer sheet, respectively,
A barcode was printed using a barcode printer (TECB-63).

The obtained image showed good fixability.

A test of fixing properties showed good fixing properties.

〔Effect of the invention〕

According to the present invention, it is possible to provide an image-receiving paper that is writable and has good ink fixability.

[Brief explanation of drawings]

1 and 2 are cross-sectional views of the image receiving paper of the present invention. l... Base material, 2... Porous hydrophobic polyurethane layer,
3... Subbing layer

Claims (1)

[Scope of Claims] 1. An image-receiving paper made of a porous sheet, in which a porous layer made of hydrophobic polyurethane is provided on a base material. 2. The image receiver according to claim 1, wherein the porous layer is formed from a water-in-oil polyurethane emulsion comprising a hydrophobic polyurethane, a surfactant, an organic solvent, and water. paper. 3. The image-receiving paper according to claim 1, wherein the porous layer has a thickness of 3 to 50 μm, and the moisture permeability of the layer alone is 1000 to 9000 g/(m^2·h). 4. The image-receiving paper according to claim 1, wherein the base material is plastic or paper.