JPH08207429A - Tape for label writers - Google Patents

Abstract

(57) [Summary] [Objective] An inkjet method is used to produce a label having good resolution and color development, and excellent environmental resistance such as light resistance, scratch resistance, and water resistance. [Structure] An ink receiving layer 2 is provided on a tape-shaped substrate 1, on which a polymer and an ultraviolet absorber made of a metal oxide such as titanium oxide, zinc oxide, selenium oxide are contained and heated. A tape for a label writer in which a porous layer 3 which can be made transparent is laminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a label writer tape, and more particularly to a label writer tape which can be printed by an ink jet method.

[0002]

2. Description of the Related Art A device called a label writer is known as a device for printing a label to be attached to a document or the like. A conventional label writer prints on a tape-shaped label base material by a thermal transfer method, and a label of various colors can be produced by combining a label base material of various colors and an ink ribbon. With this method, the label substrate and the ink ribbon must be replaced each time the color of the label is changed. Further, in the case of realizing full color, there is a problem that the consumption amount of the ink ribbon increases and the cost increases.

[0003]

On the other hand, the ink jet system is suitable as a recording system for a label writer because it can easily realize full color and is excellent in cost and image clarity. In the case of the inkjet method, the label base material needs to have high ink absorbency. Furthermore, the label is required to have environmental resistance such as scratch resistance and water resistance. Since an image is formed by a solvent-soluble dye in the inkjet method, the water resistance and weather resistance of the recorded matter are not always sufficient. In general, labels often come into contact with hands, and may be exposed to rain when used outdoors, and may be exposed to water or detergent when used for tableware, etc. High environmental resistance is required.

The present invention provides a label base for a label writer which can form an image having excellent resolution and color developability by an ink jet method and can easily produce a label excellent in environmental resistance such as scratch resistance and water resistance. The object is to provide a material, that is, a tape for a label writer.

[0005]

The present invention provides a porous layer having an ink receiving layer on a tape-shaped substrate, which is made of a polymer and an ultraviolet absorber and which can be made transparent by heating. Is a laminated tape for a label writer.

The material of the base material is not particularly limited, and various materials can be used. Specifically, polyester such as polyethylene terephthalate, polycarbonate, ET
Various plastics such as fluorine resin such as FE can be preferably used. Furthermore, natural paper, synthetic paper, cloth, etc. can also be used. These substrates may be subjected to treatments such as corona discharge treatment and undercoat for the purpose of improving the adhesive strength of the ink receiving layer.

When a transparent plastic film or the like is used as the substrate and a highly transparent ink receiving layer is used, a transparent label can be obtained. When an opaque plastic film containing a white or other color pigment or paper is used as the substrate, a white or colored label can be obtained. Even if the substrate is opaque, it is preferable that the transparency of the ink receiving layer is high because printing with high color density is possible.

The ink receiving layer formed on the substrate is preferably one mainly containing an inorganic oxide or a hydrate thereof, and particularly preferably silica gel or alumina gel.
In particular, a structure in which inorganic particles are bound with an organic binder is preferable. The inorganic particles are boehmite (Al ₂ O ₃ · nH ₂ O,
It is preferable that n = 1 to 1.5) because the ink-jet ink absorbency is good and the dye in the ink is excellent in fixability.

When the ink receiving layer is composed of hydrated alumina, the pore structure thereof is substantially composed of pores having a radius of 1 to 10 nm and the pore volume is 0.3 to 1.0 cc / g. However, it is preferable since it has sufficient absorbability and transparency. In addition to these physical properties, it is more preferable that the average pore radius of the porous alumina hydrate is 3 to 7 nm. The pore size distribution is measured by the nitrogen adsorption / desorption method.

As a method of forming the ink receiving layer, a method of applying a coating liquid in which a binder is preferably added to inorganic particles to a substrate is preferable. For example, in order to form a porous alumina hydrate layer having a pore structure as described above, alumina sol is preferably added with a binder to form a slurry, and a die coater, a roll coater, an air knife coater, a blade coater, a rod. It is preferable to adopt a method of coating on a substrate using a coater, bar coater, comma coater, etc. and drying.

As the binder, organic substances such as polyvinyl alcohol and its modified products, starch and its modified products, styrene-butadiene rubber (SBR) latex, nitrile-butadiene rubber (NBR) latex, hydroxycellulose, polyvinylpyrrolidone and the like can be used. If the amount of the binder used is too small, the strength of the ink receiving layer may be insufficient. On the other hand, if the amount is too large, the amount of ink absorbed or the amount of dye carried may be low. About wt% is preferable.

If the thickness of the ink receiving layer is too thin, the dye cannot be sufficiently carried and a label having a low color density may be obtained, which is not preferable. On the other hand, if the thickness is too large, the strength of the ink receiving layer may be reduced, or the transparency may be reduced to impair the texture, which is not preferable. The preferable thickness of the ink receiving layer is 1 to 50 μm.

On the ink receiving layer, there is provided a porous layer which is made of a polymer and an ultraviolet absorber and can be made transparent by heating. This porous layer is required to be capable of allowing the ink to penetrate into the ink receiving layer and being densified and transparent by heating when recording by an inkjet method. The polymer of the porous layer is not particularly limited, and a latex of a thermoplastic polymer is preferable.

The polymer content in the porous layer is 5
It is preferable that the content of the ultraviolet absorber is 0 to 90% by weight, and the content of the ultraviolet absorber is 10 to 50% by weight. Polymer content is 5
Less than 0% by weight, or the content of UV absorber is 50
If it exceeds 5% by weight, the porous layer is less likely to be densified, the effect of protecting the ink receiving layer becomes insufficient, and a glossy label cannot be obtained, which is not preferable.

As a means for forming the above-mentioned porous layer, it is preferable to form a coating solution containing a mixture of a polymer latex and an ultraviolet absorber on the ink receiving layer and drying it. In this case, the polymer latex and the silica sol may be either aqueous or non-aqueous, but it is preferable that both solvents are the same in terms of uniform mixing.

As the polymer latex, polyvinyl chloride (PVC) latex, styrene-butadiene rubber (SBR) latex, nitrile-butadiene rubber (NB)
R) Latex or the like may be used alone or in combination of two or more.

The polymer latex has an average particle size of 0.05.
It is preferably 0.5 μm. If the average particle size of the polymer latex is less than 0.05 μm, a porous polymer layer with good ink absorbability / permeability is not formed, and the ink sufficiently penetrates into the porous alumina hydrate layer to fix it. Therefore, a desired image cannot be formed. If the average particle size of the polymer latex exceeds 0.5 μm, the dots of the ink may become non-uniform and the image may be deteriorated. The preferable average particle size of the polymer latex is 0.08 to 0.3 μm.

The minimum temperature for forming a polymer latex film is
It is preferably in the range of 50 to 150 ° C. The minimum film formation temperature is the minimum temperature at which a polymer latex film can be uniformly formed into a film when heated. In the present invention, after coating the polymer latex, it is heated and dried under conditions such that the latex particles are bonded to such an extent that it does not form a dense film but has a certain mechanical strength in order to form a porous layer. There is a need. Minimum film formation temperature is 50
When the temperature is lower than 0 ° C., it is difficult to obtain a porous layer when a polymer latex is applied and dried, and it is difficult to obtain a porous layer. Minimum film formation temperature is 150 ° C
If it exceeds 5, it is necessary to raise the heat treatment temperature after image formation, and there is a problem of polymer decomposition and coloring, and a problem of heat denaturation of the substrate or dye, which is not preferable. The more preferable minimum film formation temperature is 65 to 130 ° C.

The ultraviolet absorber is preferably a granular or amorphous metal oxide such as titanium oxide (TiO ₂ ), zinc oxide (ZnO) or selenium oxide (CeO). The UV absorber is granular or amorphous and has an average particle size of 0.01.
It is preferable to use those having a thickness of ˜1 μm.

The silica sol has an average particle diameter of 10 to 10.
Those having 90 nm and a solid content concentration of about 1 to 20% by weight can be preferably used.

As the binder to be added to the coating liquid for forming the porous layer, the same binder as used for forming the inorganic porous layer can be used, and a polymer having a silanol group is particularly preferable. The amount of the binder added is 1 to the solid content of the silica sol (SiO ₂ conversion).
It is preferably 30% by weight.

The thickness of the porous layer is preferably 0.3 to 5 μm. If the thickness is less than 0.3 μm, the effects of improving environmental resistance such as water resistance, scratch resistance, and weather resistance when formed into a film may not be sufficient, which is not preferable. Thickness is 5 μm
If it is over, there is a risk that the ink absorbency will decrease, the image quality will deteriorate when a film is formed due to cracks, and the effects of improving environmental resistance such as water resistance, scratch resistance, and weather resistance cannot be obtained. It is not preferable because there is. The more preferable thickness of the porous layer is 0.5 to 3 μm.

The solid content concentration of the polymer latex is not particularly limited. A latex having a solid content concentration of 2.5 to 50% by weight can be appropriately used. It should be noted that other polymer component having a binder action may be added to the polymer latex.

The coating method for the coating liquid for forming the porous layer is not particularly limited, and a die coater, roll coater, air knife coater, blade coater, rod coater, bar coater, gravure coater and the like can be used. When a polymer latex is used, the drying is preferably carried out at a temperature not higher than the minimum film-forming temperature of the polymer latex used.

In the tape of the present invention, it is preferable that an adhesive layer is formed on the back side of the recording surface, that is, the back side of the surface on which the ink receiving layer and the porous layer are formed, and a release paper is further laminated. . In this case, the tape can be stored in a cartridge in a wound form, and after the tape after printing is cut, the release paper can be peeled off and attached to a desired place. The thickness of the release paper is preferably 10 to 200 μm. If the thickness of the release paper is less than 10 μm, it becomes difficult to remove the release paper. Conversely, if the thickness exceeds 200 μm, the total thickness of the tape increases, and the length of the tape that can be stored in the cartridge decreases, which is preferable. Absent.

The width of the tape can be appropriately selected according to the desired label size. Generally, about 5 to 50 mm is suitable. In the manufacturing process, it is preferable to cut a sheet having a width larger than this into a tape. This tape is preferably wound into an appropriate diameter, placed in a cartridge made of resin or the like, and attached to a label writer.

An example of a cross section of the tape for label writer of the present invention is shown in FIG. In FIG. 1, an ink receiving layer 2 is formed on a tape-shaped substrate 1, and a porous layer 3 is further formed.
Are stacked. The pressure-sensitive adhesive layer 4 and the release paper 5 are laminated on the back surface thereof.

When characters or images are formed on the tape for label writer of the present invention from above the porous layer by the ink jet method, the ink penetrates through the porous layer and reaches the ink receiving layer to be fixed. After that, when the porous layer is densified by heat treatment, a transparent film is formed. The heating means is not particularly limited, and an ordinary heating heater, thermo module, hot air, or the like can be adopted. Either a contact method or a non-contact method can be adopted. The heat treatment temperature does not have to be a particularly high temperature as long as it is a temperature at which the porous layer is densified,
When the porous layer is formed of a polymer latex and silica sol, the temperature may be at least the latex film formation minimum temperature. It is preferable that a label having a film is immediately produced by performing printing and heat treatment in one label writer, but it is possible to heat it separately with an iron after printing the label.

The resulting transparent film has a protective effect of improving the water resistance and weather resistance of the label. Here, "transparent" means that characters (including figures) recorded on the ink receiving layer can be observed through the film. It is preferably colorless, but may be colored for imparting a design property. The thickness of the film after densification is preferably 0.3 to 5 μm. The thickness of the transparent film is 0.
If it is less than 3 μm, the effect of protecting the ink receiving layer may not be sufficient, which is not preferable. The thickness of the transparent film is 5μ
If it exceeds m, the protective effect is not further increased, and conversely, the image quality may be deteriorated due to the hiding of the film, or the film may peel off or the label may curl, which is not preferable.

[0030]

In the present invention, the transparent film obtained by densifying the porous film covers the ink receiving layer so that the dye fixed on the ink receiving layer allows oxygen, ozone, N
Prevents reaction with O _x, etc., or volatilization,
Further, it has a function of blocking ultraviolet rays. Even if the base material is a material such as paper that allows air to permeate therethrough, the dye is more effectively fixed to the transparent film side of the ink receiving layer, and therefore the same effect is exhibited. Further, the transparent coating coats and protects the ink receiving layer, whereby the environmental resistance such as scratch resistance, water resistance, solvent resistance, weather resistance and stain resistance of the label is improved. In addition, the UV absorber significantly improves the light fastness of the ink.

[0031]

【Example】

[Example 1] 100 g of an alumina sol having a solid content of 18% by weight synthesized by a method of hydrolyzing and peptizing aluminum alkoxide
And 32 g of a 6.2 wt% aqueous solution of polyvinyl alcohol were mixed to prepare a coating liquid. This coating liquid was applied onto a polyethylene terephthalate film (white film, thickness: 38 μm) using a die coater so that the coating amount after drying was 25 g / m ² . This was dried and then heat treated at 140 ° C. to form a porous boehmite layer.

On this boehmite layer, a mixture of PVC latex having a solid content of 10% by weight and an ultraviolet absorber (TiO ₂ ) having an average primary particle diameter of 10 nm (solid content weight ratio 8:
2) was applied using a die coater and dried at 60 ° C. After drying, a 2 μm thick porous layer was formed.

Next, an adhesive layer is formed on the side where the boehmite layer and the porous layer are not formed, and a thickness of 75 μm is formed thereon.
Release paper was laminated. As a result, when the release paper is peeled off, a sheet that can be adhered to the adherend is obtained. This sheet was cut into a tape shape having a width of 15 mm and a length of 10 m and wound up to obtain a tape for a label writer.

This tape can be printed with an ink jet printer, and after printing, the porous layer is printed at 100 ° C.
A transparent film can be formed by heating to. After that, it is cut into an appropriate length and the release paper is peeled off, so that the label can be attached to a desired place.

Example 2 A mixture of SBR latex having a solid content of 5% by weight and an ultraviolet absorber (TiO ₂ ) having an average primary particle diameter of 20 to 30 nm and an average primary particle diameter of 10 nm (solid content weight ratio 8: 2) was used. The boehmite layer on the white film formed in the same manner as in Example 1 was coated with a die coater to a dry thickness of 1 μm and dried at 90 ° C.
I got a tape for a label writer. This tape can be printed with an inkjet printer, and after printing,
A transparent film can be formed by heating the porous layer to 130 ° C. After that, it is cut into an appropriate length and the release paper is peeled off, so that the label can be attached to a desired place.

[0036]

The tape for label writer of the present invention is
High quality printing is possible by the inkjet method,
It has excellent quick-drying properties and color development, and can be used for full-color applications. Furthermore, by printing the porous layer after printing,
A label having excellent environmental resistance such as scratch resistance, water resistance, weather resistance, solvent resistance, stain resistance, and high strength can be produced. Therefore, the obtained label has storage stability that maintains high image quality for a long period of time, and particularly has good light resistance. The label writer tape of the present invention is particularly suitable for recording using a water-based ink.

Furthermore, the transparentized porous layer has the effect of increasing the gloss of the label. Even when the transparency of the ink receiving layer is low, the dense porous layer covers the ink receiving layer, so that printing with a higher color density becomes possible as compared with the case where there is no film.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a cross section of an example of a tape for label writer of the present invention.

[Explanation of symbols]

 1: Tape-shaped substrate 2: Ink receiving layer 3: Porous layer 4: Adhesive layer 5: Release paper

Claims (4)

[Claims] 1. A label writer having an ink receiving layer on a tape-shaped substrate, and a porous layer made of a polymer and an ultraviolet absorber, which can be made transparent by heating, is laminated on the ink receiving layer. tape. 2. The tape for a label writer according to claim 1, wherein the porous layer is formed by applying and drying a mixture of a polymer latex and an ultraviolet absorber. 3. The tape for a label writer according to claim 1, wherein the ultraviolet absorber is a metal oxide. 4. The tape for a label writer according to claim 1, 2 or 3, wherein the printing method is an ink jet method.