JPH01282399A - Recording sheet - Google Patents

Abstract

PURPOSE:To obtain a printer paper having excellent ink-fixing and generating little dust by successively laminating a substrate with an ink-receptor layer composed mainly of a specific acrylic resin and with a surface layer composed mainly of a specific resin. CONSTITUTION:A substrate such as paper or plastic sheet is successively laminated with (A) an ink-receptor layer composed mainly of an acrylic resin having a glass transition temperature of <=20 deg.C (preferably 2-ethylhexyl methacrylate) and (B) a surface layer composed mainly of a resin having a glass transition temperature of >=80 deg.C (preferably at least one kind of polymer selected from homopolymer of methyl methacrylate, t-butyl methacrylate or styrene and copolymer of the above monomers).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a recording sheet suitable for a wire dot printer using an ink ribbon, and more particularly to a recording sheet with excellent ink receptivity.

<Prior art> Wire dot printers are one of the most common printers available today, and are widely used. It is a dispersion of pigment coloring material, and when printed, a wax-based substance is driven into the irregularities on the surface of the recording paper to fix it.

However, in recent years, with the diversification of recording media, it has become desirable for wire dot printers to be able to print on special sheet-like materials that are different from conventional paper, such as various plastic films, synthetic fiber sheets, and metallized sheets. However, these sheet-like materials have no or very few surface irregularities, so even if printing is done properly, the ink cannot be fixed properly, and the surface is rough. There was a problem in that the ink would fall off or be transferred to other objects even if rubbed with a brush.

In addition, in the case of conventionally used recording paper, the generation of paper dust cannot be suppressed due to the nature of the paper itself, and it is not suitable for use in environments where dust and dust are a problem, such as in a clean room. First, there is a demand for a recording sheet that does not generate paper dust or the like as an alternative to paper. In response to these demands, sheets such as plastic film solve the problem of paper dust, but as mentioned above (there is a problem with ink fixation), recording sheets that do not have any practical problems in environments such as clean rooms are not available. It is requested.

On the other hand, in order to improve the ink fixation properties of plastic films such as those mentioned above, a method of providing a surface layer containing a large amount of pigment particles on the surface has been proposed, but there are problems such as falling off of the pigment and poor appearance, especially for overhead projectors. There is a problem in that transparency is impaired when used for wire dot printers, and therefore, a film-type recording sheet of sufficiently satisfactory quality for use in wire dot printers has not yet been obtained.

<Problems to be Solved by the Invention> In view of the above circumstances, the present invention provides a recording sheet suitable for printing with a wire dot printer, which has excellent ink fixing properties and does not generate dust such as paper powder. It is.

<Means for Solving the Problems> The present invention provides an ink receiving layer mainly composed of an acrylic resin having a glass transition temperature of 20° C. or lower on at least one side of a support, and a resin having a glass transition temperature of 80° C. or higher. This is a recording sheet characterized by sequentially laminating surface layers containing as a main component.

The ink-receiving layer constituting the recording sheet of the present invention is a part that receives ink from a recording means and fixes it during recording,
It contains an acrylic resin having a glass transition temperature (hereinafter referred to as Tg) of 20° C. or lower as a main component.

The acrylic resin with a Tg of 20°C or less herein refers to homopolymers of various monomers such as acrylic and methacrylic acids and esters, and their derivatives, as well as copolymers thereof, or, for example, other polymers. The Tg of a copolymer with a vinyl monomer is 20°C or less. Examples of acrylic resins with a Tg of 20°C or lower include polymethyl acrylate (7g8°C, hereinafter "g" is shown in parentheses), polyethyl acrylate (-22°C), polyisopropyl acrylate (-5°C), poly2 -Hydroxyethyl acrylate (-15°C), poly n-butyl methacrylate (20°C), poly n-amyl methacrylate (
10℃), poly n-hexyl methacrylate (-5℃)
, poly n-octyl methacrylate (-20°C), poly n-tetradodecyl methacrylate (-9°C), poly 2
-Ethylhexyl methacrylate (-10°C), Poly2
-dimethylaminoethyl methacrylate (19°C) and the like, but are not limited to these.

The acrylic resin for the ink receiving layer has a Tg of 2 as described above.
A resin having a temperature of 0°C or lower is used, and a resin having a temperature of -10°C or lower is particularly suitable, and 2-ethylhexyl methacrylate resin is particularly suitable. In the ink receiving layer, the Tg
It is preferable that the content of acrylic resin having a temperature of 20° C. or lower is 30 to 100%.

The thickness of the ink-receiving layer is preferably about 2 to 10 μm; if it is less than 2 μm, sufficient ink fixing properties cannot be obtained;
Even with the above, commensurate effects cannot be obtained, and problems arise in terms of manufacturing, raw material costs, and the like.

The surface layer constituting the recording sheet of the present invention protects the ink-receiving layer and provides the recording sheet with good handling properties.
It imparts blocking resistance, is provided so that the head wire of a wire dot printer penetrates the surface layer during recording, and contains a resin having a Tg of 80° C. or higher as a main component.

Resins for the surface layer include homopolymers and copolymers of various monomers such as acrylic and methacrylic acids and esters, and their derivatives, or copolymers with other vinyl monomers. Tg of merging etc. is 80
℃ or higher is used. Examples of resins with a Tg of 80°C or higher include polyacrylic acid (Tg 106°C, hereinafter Tg is shown in parentheses), polymethacrylic acid (130°C)
, polymaleic acid (130℃), polymethyl methacrylate (105℃), polyisopropyl methacrylate (
81°C), poly t-butyl methacrylate) (107°C)
, polyphenyl methacrylate (110°C), polystyrene (95°C), polyacrylonitrile (100°C),
Examples include, but are not limited to, polyacrylamide (153° C.).

For the surface layer, a resin having a Tg of 80° C. or higher as described above is used, and methacrylic and styrene resins are particularly preferred, and among these, methyl methacrylate, t-butyl methacrylate, and styrene homopolymers or copolymers thereof are used. Polymers are particularly preferred. In the surface layer, the Tg is 8
It is preferable that the content of the resin having a temperature of 0° C. or higher is 50 to 100%.

The thickness of the surface layer is preferably about 2 microns or less, and if it is more than 2 microns, good ink stability cannot be obtained.

In the present invention, the support includes, for example, polyester such as polyethylene terephthalate, various acrylic and methacrylic polymers, plastic films or sheets such as polyvinyl chloride, polycarbonate, polyimide, acetate, cellophane, and celluloid, as well as synthetic fiber sheets, Examples include metal-deposited films, but the film is not limited to these, and may be selected as appropriate in consideration of the adhesion of the ink-receiving layer provided on the surface depending on the recording purpose and use.

The recording sheet of the present invention is composed of the support, the ink receiving layer and the surface layer as described above, and various additives may be added to these as necessary. For example, polyethylene oxide, silica, clay, talc, kaolin, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithopone, satin, etc. are used to improve handling and blocking properties. In addition to adding pigments such as white, additives such as dispersants, fluorescent dyes, antifoaming agents, lubricants, and low-resistance agents can also be used for the purpose of improving sheet productivity, recording characteristics, and the like.

In order to produce the recording sheet of the present invention, a coating solution prepared by dissolving or dispersing the materials for forming each layer in water or an appropriate solvent is applied using a roll coating method, a plate coating method, a spray coating method, or the like. There are methods such as applying and drying by air knife coating method, rod bar coating method, etc., and methods of laminating a mixture of uniformly mixed materials for forming each layer by hot melt coating method, laminate coating method, etc. The ink-receiving layer and the surface layer may be sequentially laminated on the support by appropriately selecting one of these methods depending on the material used.

In the recording sheet of the present invention, an adhesive layer is provided on the back side of the support, that is, on the side where the ink receiving layer and the surface layer are not formed, using a commonly used adhesive,
Furthermore, if necessary, by laminating a release film or sheet with release properties on the adhesive layer, it can be used as an adhesive sheet or label that can be attached as desired. The usage area can be thickened (widened).

The method for measuring the glass transition temperature in the present invention is as follows. Measurements were performed using a differential scanning calorimeter with a compensation method and alumina as a standard substance, as shown in Fig. The temperature of No. 2 was taken as the glass transition temperature.

<Examples> Next, the present invention will be explained according to examples. In addition, all parts expressing the formulation indicate parts by weight.

Example 1 A coating liquid having the following composition was coated on one side of a polyethylene terephthalate film having a thickness of 100 μm using a Meyer bar coater and dried to form an ink-receiving layer. Note that the thickness of the ink receiving layer was 5 μm.

Next, a coating liquid having the following composition was applied to the surface of the ink-receiving layer using a gravure coater and dried to form a surface layer, thereby producing a recording sheet of the present invention. The thickness of the surface layer is 1μ.
And so.

Example 2 A recording sheet of the present invention was obtained in the same manner as in Example 1 except that the coating liquid for the surface layer had the following composition.

Example 3 A recording sheet of the present invention was obtained in exactly the same manner as in Example 1, except that the coating liquid for the surface layer had the following composition.

Example 4 A recording sheet of the present invention was obtained in exactly the same manner as in Example 1, except that the coating liquid for the ink-receiving layer had the following composition.

Example 5 A recording sheet of the present invention was obtained in the same manner as in Example 1 except that a 125 μm thick opalescent polyethylene terephthalate film was used as the support.

Example 6 A recording sheet of the present invention was obtained in the same manner as in Example 1 except that a biaxially stretched polypropylene film having a thickness of 100 μm was used as the support.

Comparative Example 1 A comparative recording sheet was prepared in exactly the same manner as in Example 1, except that the coating liquid for the ink-receiving layer had the following composition.

Comparative Example 2 A comparative recording sheet was prepared in exactly the same manner as in Example 1, except that the coating liquid for the surface layer had the following composition.

Comparative Example 3 A coating liquid having the following composition was coated on a polyethylene terephthalate film with a thickness of 100μ using a Meyer bar coater to a film thickness of 5μ.
A recording sheet for comparison was prepared by coating and drying to give the following properties.

Regarding the recording sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 3, wire dot printers (manufactured by NEC Corporation, P
C-PR201, ink ribbon is PC-PR-201-
A printing test was conducted using 01). The results are shown in the table-
1, it was confirmed that the recording sheet of the present invention exhibits extremely good ink retention ability when used in a wire dot printer that prints with an ink ribbon based on a wax-based substance.

[Margin below]

Table-1 The evaluation method for each item in Table-1 is as follows.

(1) Ink receptivity: Visually evaluated good results as ◯, and poor results as ×.

(:2) Ink retention: Immediately after printing, the printed area was rubbed with a fingertip. If the ink did not come off, it was evaluated as ○, and if the ink did come off, it was evaluated as bad.

<Effects of the Invention> Since the recording sheet of the present invention has excellent ink retention ability, it is possible to print on sheet-like materials other than paper such as plastic films, which were practically impossible to print with conventional wire dot printers. This has the advantage that the wire dot printer can be used in a very wide range of applications, including use in clean rooms, printing on sheets for overhead projectors, and many other applications.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing how to determine the glass transition temperature in the present invention. 1... Endothermic curve 2... Intersection point 3... Baseline

Claims (3)

[Claims] (1) On at least one side of the support, an ink-receiving layer mainly composed of an acrylic resin with a glass transition temperature of 20°C or lower and a surface layer mainly composed of a resin with a glass transition temperature of 80°C or higher are sequentially formed. A recording sheet characterized by being laminated. (2) The recording sheet according to claim 1, wherein the acrylic resin having a glass transition temperature of 20° C. or lower is 2-ethylhexyl methacrylate resin. (3) The resin having a glass transition temperature of 80°C or higher is at least one polymer selected from methyl methacrylate, t-butyl methacrylate, styrene homopolymers, and copolymers thereof. A recording sheet according to claim 1.