JPH0342589B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a recording sheet for printing and recording by an inkjet printer. More specifically, the present invention relates to a recording sheet in which a water-soluble polymer coating is provided on a non-water-absorbing support made of polyester film, in which the adhesion between the support and the water-soluble polymer coating is improved.

Prior Art Inkjet printers use ink that does not dry easily in order to prevent clogging of jet nozzles, and its components generally include binders, dyes, solvents, additives, etc. dissolved in water. Therefore, when printing is performed using an inkjet printer, a water-absorbing recording medium such as ordinary paper is used.

By the way, with the spread of overhead projectors (OHP) in recent years, it is conceivable that transparent plastic film can be printed with an inkjet printer and used as base paper for OHP. However, plastic film, especially the polyester film used as regular OHP base paper, has almost no water absorption, so when printing records with an inkjet printer, the ink may run or different color inks may mix, resulting in poor clarity. It is difficult to keep accurate records.

In order to improve this problem, it has been proposed to provide a water-soluble polymer film on a support having low water absorption (Japanese Patent Laid-Open No. 146786/1986). However, this proposal was proposed primarily for supports such as paper, and water-soluble polymers have little adhesion to plastic films, especially polyester films, which have almost no water absorption, making it easy to form a film. Since it peels off, it cannot be put to practical use.

Purpose of the Invention The present inventors have conducted intensive research to improve this drawback, and as a result, have found that it can be solved by providing a specific anchor coat layer, and have arrived at the present invention.

An object of the present invention is to provide a recording sheet with improved adhesion between a polyester film, which is a non-water-absorbing support, and a water-soluble polymer.

Structure and Effects of the Invention An object of the present invention is to provide a recording sheet in which a water-soluble polymer film is provided on a non-water-absorbing support, wherein the support is made of a polyester film, and a water-based copolymerized polyester is coated on the film. This is achieved by a recording sheet characterized by having an anchor coat layer as a main component and further having a water-soluble polymer film on the anchor coat layer.

In the present invention, the non-water-absorbing support is made of polyester film. This polyester film has excellent transparency and mechanical strength. Polyester film thickness starts from 50μ
200μ and a transparent film with a haze of 10% or less, which is preferably a film made of polyethylene terephthalate or a copolyester containing 70 mol% or more of polyethylene terephthalate, or a blend containing 70% or more of these. More preferred is a biaxially stretched film.

Examples of water-soluble polymers include polyacrylic acid, polymethacrylic acid or their esters, salts, and copolymers thereof, polyhydroxyethyl methacrylate and copolymers thereof, starches, polyvinylpyrrolidone, polyvinyl Examples include alcohol, polyethylene glycol, cellulose derivatives such as methylcellulose, and hydroxyethylcellulose, but are not limited to these.

The anchor coat layer needs to have adhesion to a non-water-absorbing support, especially a polyester film, and swellability to water, and is mainly composed of aqueous copolymerized polyester. Such aqueous copolymerized polyesters include terephthalic acid,
It is a product obtained by copolymerizing one or more components of isophthalic acid or aliphatic acids with a glycol component such as ethylene glycol, propylene glycol, butylene glycol, or polyethylene glycol, and contains a carboxy group in the middle or end of the molecular chain. Preferably, it has a sulfonic acid group or a metal salt thereof, ammonium acid, etc., so that it can be dissolved or dispersed in water. Examples of these commercially available products include WD Size (Eastman Kodak), Pesresin (Takamatsu Yushi), and Fine Tetsk (Dainippon Ink).

Although the aqueous copolymerized polyester can be used alone to form the anchor coat layer, it is preferable to use it in addition to melamine such as methoxymethylated melamine, since this further improves the adhesion. The thickness of the anchor coat layer is preferably 0.01μ to 5μ,
More preferably, it is 0.02μ to 2μ.

For forming the anchor coat layer, a typical coating device such as a bar coater, gravure coater, reverse roll coater, knife coater, etc. can be used. Further, it is preferable that the anchor coat layer is formed during film formation, and it is also preferable that the anchor coat layer and the water-soluble polymer layer are formed using a continuous coating device.

By forming the above-mentioned anchor coat layer, the adhesion between the non-water-absorbing support, especially the polyester film, and the water-soluble polymer film is improved, making it a practical OHP product when printing and recording with an inkjet printer. A raw paper is obtained.

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

Example 1 A 5% aqueous solution having the following composition was coated on one side of a biaxially stretched polyethylene terephthalate film with a thickness of 100 μm using a bar coater to form an anchor coat layer with a dry thickness of 1 μm.

Aqueous copolymerized polyester WD size (manufactured by Eastman Kodak) 90 parts by weight Sumitex Resin M-3 (melamine manufactured by Sumitomo Chemical) 10 parts by weight Polyvinyl alcohol (saponification degree 75%) as a water-soluble polymer on the obtained film ) was applied to a thickness of 7μ. The anchor coat layer of the obtained film did not peel off at all even when peeled off with cellophane tape. Here, what is cellophane tape peeling?
A cut is made in the coating layer, a cellophane tape is attached in a direction perpendicular to the cut line, and the cellophane tape is firmly pressed down with fingers to ensure a tight fit.The cellophane tape is then quickly peeled off to examine the adhesion properties of the coating layer.

On the other hand, for comparison, a polyvinyl alcohol layer was directly formed in the same manner as above on a 100 μm thick biaxially stretched polyethylene terephthalate film on which no anchor coat layer was formed. The obtained polyvinyl alcohol film layer was easily peeled off using the cellophane tape described above.

Claims (1)

[Claims] 1. A recording sheet in which a water-soluble polymer film is provided on a non-water-absorbing support, wherein the support is made of a polyester film, and an anchor coat layer containing a water-based copolymerized polyester as a main component is provided on the film. 1. A recording sheet, further comprising a water-soluble polymer film provided on the anchor coat layer.