JPS61235182A - Recording sheet - Google Patents

Abstract

PURPOSE:To obtain a recording sheet which is made of a transparent material to be recorded and dries in a short time even if recorded thereon in a high density with an ink for an ink jet printer, by forming a polyvinyl alcohol film having cationic groups as well as a specified range of degree of saponification on at least one surface of a transparent substrate. CONSTITUTION:On at least one surface of a transparent substrate, a polyvinyl alcohol film having cationic groups and a degree of saponification 30-90% is formed. A transparent plastic film is preferable for a transparent substrate. The cation modified polyvinyl alcohol can be easily obtained by copolymerizing a vinyl monomer having cationic groups with a vinyl acetate monomer. Use of a polyvinyl alcohol having a degree of saponification at a value below 30% or above 90% results in lowering the drying characteristics of ink and deteriorating the recording condition. In this manner, a recording sheet consisting of the transparent substrate and the film allowing rapid recording with an ink jet printer, can be obtained.

Description

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

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 jet nozzles, and the components of this ink generally include binders, dyes, solvents, additives, etc. dissolved 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 paper for overhead projectors (OHP). However, the transparent recording material usually consists of Plus Deck film, but this plastic film is hydrophobic and does not absorb any ink for inkjet printers, so ink recorded directly on it does not dry easily and is 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.

Purpose of the Invention As a result of intensive research to develop a recording sheet that is a transparent recording material that dries in a short time even when recorded with high density ink for inkjet printers, the inventor discovered that
It has reached the light of day.

Therefore, an object of the present invention is to provide a recording sheet comprising a transparent support and a film that can be rapidly recorded with an inkjet printer. A further object of the present invention is to provide a recording sheet in which the ink for an inkjet printer dries in a short period of time in high-density printing and recording, thereby allowing rapid printing and recording. Another object of the present invention is to provide a recording sheet useful for overhead projects.

Structure and Effects of the Invention According to the present invention, a film of polyvinyl alcohol having a cationic group and having a saponification degree of 30 to 90% is formed on at least one side of a transparent support. This is achieved by a recording sheet made of

The transparent support referred to in the present invention is preferably a transparent plastic film, such as polynisdel film,
polyamide film, acetate film, borino j-
Examples include carbonate film and polyvinyl chloride film.

The thickness of the support used is usually 25-200μ, preferably 50-150μ. If it is too thin, it will lack rigidity and it will be difficult to insert it into an inkjet printer, and if it is too thick, it will be difficult to handle and the price per sheet will also increase, so neither is preferable.

Furthermore, the aged polyvinyl alcohol used in the present invention needs to have a cationic group in its molecule. Such cation-modified polyvinyl alcohol can be easily obtained by copolymerizing a vinyl monomer having a cationic group and a vinyl acetate monomer. Examples of vinyl monomers having a cationic group include vinylbenzyl 1-trimethylammonium chloride, N-methyl-4-vinylpyridium chloride, 2-methacryloyloxyethyltrimethylammonium chloride, and 2-acrylooxyethyldimethylsulfonium chloride. etc. can be mentioned. The content of such cationic vinyl monomer is 0.1 to 10
Moderation of mole % is preferred. If the number of times of inclusion is too small, the effect will not be exhibited, and if it is too large, the hygroscopicity of the film will increase, resulting in stickiness of Sea 1-, making practical use difficult.

Furthermore, the polyvinyl alcohol has a saponification degree of 30 to 90.
Must be between %. If it is less than 30% or more than 90%, the drying properties of the ink will be reduced, the time required for no stains to occur when rubbed with a finger will be significantly longer, and the recording state will be disturbed.

When forming a polyvinyl alcohol film on a support, polyvinyl alcohol may be applied directly as it is, but if the adhesion between the support and the film formed is insufficient, the film may be formed. Preferably, a brimer is applied to the support before the coating is applied. If a polyvinyl alcohol film is formed on one side of the support, it is sufficient for printing, but forming a film on both sides of the support makes it difficult for the recording sheet to withstand large changes in temperature and humidity. This is more preferable because deformation (curl) can be suppressed and compatibility with inkjet printers can be improved.

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 dry thickness of the film is preferably 1 to 20 microns, more preferably 2 to 15 microns. If the film is too thin, 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, both of which are undesirable.

The recording sheet of the present invention can be printed using an inject blink, and further has a dot density of 6 to 12 dots/a.
It is useful for printing records using a high-density type inkjet printer.

Example The present invention will be further explained below with reference to Examples.

Examples 1 to 3 and Comparative Examples 1 to 2 On one side of a 100μ thick polyethylene terephthalate film, 2 moles of 2-methacryloyloxyethyltrimethylammonium chloride and 98 moles of vinyl acetate were polymerized and polymerized by a conventional method. The saponification degree shown in Table 1 obtained by
An aqueous solution of polyvinyl alcohol having 0 cationic groups was applied using a bar coater to a dry thickness of 5 μm.

A model symbol was printed on the obtained recording sheet using an inkjet printer with a density of 6 dots/m, and the drying state of the ink was examined. The results are shown in Table 1.

Comparative Examples 3 to 5 Recording sheets were produced in the same manner as in Examples 1 to 3, except that polyvinyl alcohol containing no cationic groups and having a degree of saponification shown in Table 1 was used as the polyvinyl alcohol. , evaluated using an inkjet printer. The results are shown in Table 1.

Notes to Table 1: 1) Abbreviation for cation-modified polyvinyl alcohol 2) Abbreviation for polyvinyl alcohol 3) Unexamined Japanese Patent Application Publication No. 2003-100000 until no stains occur even when rubbed with fingers 4) Visual observation of the appearance of the film after recording (disturbed state of dots) From the table above, it can be seen that the drying state of the ink is significantly improved by forming a film of polyvinyl alcohol that has a cationic group and has a degree of saponification within a specific range.

Claims (1)

[Claims] A recording sheet formed by forming a film of polyvinyl alcohol having a cationic group and having a degree of saponification of 30 to 90% on at least one side of a transparent support.