JPS61237681A - Recording sheet - Google Patents

Abstract

PURPOSE:To enable rapid recording to be performed by an ink jet printer and obtain clear images, by providing a film comprising a mixture of a specified vinyl alcohol and polyvinyl pyrrolidone on at least one side of a transparent base. CONSTITUTION:The base is preferably a transparent plastic film. Polyvinyl alcohol must have an anionic group in its molecule, can be obtained by copolymerizing a vinyl monomer having an anionic group with a vinyl acetate monomer, and the saponification degree thereof is set to be not lower than 75%. A polyvinyl alcohol having a saponification degree of lower than 75% is not preferable because of its poor compatibility with polyvinyl pyrrolidone. The mixing ratio of polyvinyl alcohol to polyvinyl pyrrolidone is preferably 9.5:0.5-0.5:9.5, the dry thickness of the film of the mixture is preferably 0-20mum, and the film is provided by an ordinary coating means.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a recording sheet, and more particularly to an inkjet printer in which a film is formed on at least one side of a transparent support to enable high-density recording with an inkjet printer. Regarding the record sheet for use.

Background Art Inkjet printers have become popular in recent years due to their excellent features such as sharpness of recording, quietness, and ease of color printing. Inkjet printers use ink that does not dry easily to prevent clogging of the jet nozzle, and the components of this ink are binder and dye.

It is generally prepared by dissolving solvents, additives, etc. in water.

Therefore, when printing and recording with an inkjet printer, the recording material must have water absorption properties, and paper specially designed to provide sufficient ink absorption properties is usually used.

On the other hand, as inkjet printers become more color-oriented, there is an increasing demand for recording on transparent recording materials and using them as base paper for overhead printers (OHP). However, the transparent recording material is usually made of plastic film, which is hydrophobic and does not absorb any inkjet printer ink, so ink recorded directly on it does not dry easily and can be used with fingers. If they are rubbed or overlapped, the recorded area will get dirty and become unusable.

Various proposals have been made to improve this, but all are insufficient. In particular, when recording ink at high density, the ink drying properties are insufficient (and it is difficult to obtain clear images) with the methods proposed so far.

Purpose of the Invention The present inventors have developed a transparent recording material that dries in a short time even when recording at a high dot density of 6 to 16 dots per ink for inkjet printers. The present invention was developed as a result of intensive research to develop a recording sheet that provides clear images without any dot disturbances.

Therefore, the object of the present invention is to provide a transparent support that can be rapidly recorded with an inkjet printer.

Another object of the present invention is to provide a recording sheet comprising a film that provides a clear image. A further object of the present invention is to provide a high-density printing record using an ink for an inkjet printer, in which the ink dries in a short time and rapid print recording is possible;
The object of the present invention is to provide a recording sheet that provides a clear image. Another object of the present invention is to provide a recording sheet useful for overhead projects.

Structure and Effect of the Invention This object of the present invention is to provide polyvinyl alcohol and polyvinylpyrrolidone having a heptanionic group on at least one side of a transparent support and having a saponification degree of 75 degrees or more. This is achieved by a recording sheet characterized by forming a film containing a mixture of.

The transparent support used in the present invention is preferably a transparent plastic film, such as a polyester film or a polyamide film.

Examples include acetate film, polycarbonate film, and polyvinyl chloride film.

The thickness of the support used is suitably 25 to 200 p, preferably 50 to 150 p.

If it is too thin, it will lack rigidity and will be difficult to insert into an inkjet printer, and if it is too thick, it will be difficult to handle or
Both are undesirable because the price per sheet also increases.

The polyvinyl alcohol referred to in the present invention must have an anionic group within the molecule. Such anion-modified polyvinyl alcohol can be easily obtained by copolymerizing a vinyl monomer having a pentanionic group with vinyl acetate heptamer. Vinyl monomers having anionic groups include acrylic acid, methacrylic acid,
Styrene sulfonate ° Bi = 71 sulfonate can be raised. The content of the anionic vinyl salt is preferably 0.1 to 20 mol. If the content is too small, the effect will not be achieved, and if the content is too large, the film will become highly hygroscopic, causing the sheet to become sticky, making it difficult to use it practically. In addition, the polyvinyl alcohol mentioned above must have a degree of saponification of 75 degrees or more.
5- Yes. Those having a saponification degree of less than 7596 are not preferred because they have poor compatibility with polyvinylpyrrolidone. Polyvinyl alcohol having a saponification degree of 8096 or higher is more preferably used. Moreover, polyvinylpyrrolidone preferably has a molecular weight of 10,000 to 1,000,000.

As such polyvinyl alcohol, commercially available polyvinyl alcohols that satisfy the above conditions can be used.

Polyvinyl 7 alcohol to polyvinyl heilidon, preferably 9:1 to 1:9, is suitable from the viewpoint of drying properties of the ink. The film of the mixture formed has a dry thickness of 1 to 20μ,
Furthermore, 2 to 15μ is appropriate. If the film is too thick, the drying of the ink will be slow and it will be impractical, while if it is too thick, the price per sheet will increase and coating will be difficult, so both are unfavorable.

When forming a film on a support, the coating blood may be applied directly as it is, but if the adhesion between the support and the formed film is insufficient, it may be necessary to apply it before forming the film. Preferably, a primer is provided on the support.

Furthermore, if the film is formed on one side of the support, it is sufficient for printing, but forming a film on both sides of the support will cause the recording sheet to deform due to wide changes in temperature and humidity. This is more preferable because it can suppress curling and improve compatibility with inkjet printers.

As a method for forming a film on a transparent support, conventional coating methods such as gravure coating, barcode coating, reverse roll coating, and knife coating can be used.

The recording sheet of the present invention is useful for printing using an inkjet printer, and further for printing using a high-density type inkjet printer having a dot density of 6 to 16 dots per minute.

One fu Example Next, the present invention will be explained with reference to Examples.

Examples 1 to 3 and Comparative Examples 1 to 2 Saponified polymers obtained by polymerizing and saponifying 5 moles of methacrylic acid and 95 moles of vinyl acetate on one side of a polyethylene terephthalate film with a thickness of 100 μ by a conventional method. Polyvinyl alcohol having a 7-ionic group with a polymerization degree of 86 and a polymerization degree of 1300 and a molecule l of approximately 700
, 000 polyvinylpyrrolidone (-9 to Rubiscoll)
An aqueous solution (10% concentration) prepared by mixing 0: BASF (manufactured by BASF) in the ratio shown in Table 1 was coated with a bar coater to a dry thickness of 5 μm.

A model symbol was printed on the prepared recording seed using a high-density inkjet printer with a dot density of 12 dots/s++, and the drying state of the ink was examined.

The results are shown in Table 1.

Comparative Examples 3 to 5 Recording sheets were prepared in the same manner as in Examples 1 to 3, except that polyvinyl alcohol with a degree of saponification of 86- (Gohsenol GH-17; manufactured by Memoto Gosei Kagaku) was used as the polyvinyl alcohol, Evaluation was performed using an inkjet printer. The results are shown in Table 1.

From the above table, it can be seen that the drying state of the ink is significantly improved by providing a film using a combination of polyvinyl alcohol having a 7-ion group and polyvinylbilidone.

Claims (1)

[Claims] 1. A recording sheet characterized in that a film made of a mixture of polyvinyl alcohol and polyvinylpyrrolidone having an anionic group and having a degree of saponification of 75% or more is formed on at least one side of a transparent support.