JPH029676A - Aqueous ink recording sheet - Google Patents

Abstract

PURPOSE:To perfectly provide various characteristics required as an OHP sheet by providing a coating layer of a composition containing at least chitin or/and chitosan to at least the single surface of a transparent polymer film. CONSTITUTION:The proper visible light transmissivity of a polymer film 1 is 75% or more, especially, 80% or more and the proper thickness thereof is about 12-150mum, especially, about 25-120mum. Chitin is one of polysaccharides composed of amino sugar having an MW of about 20,000-50,000 and composed of a straight chain molecule constituted of a beta-1, 4 bond of a D-glucosamine group whose amino group is acetylate and chitosan is one of basic polysaccharides composed of glucosamine similarly having an MW of about 20,000-500,000 and obtained by heating chitin along with conc. alkali. The proper coating thickness of said film is about 1-30mum, especially, 2-20mum on a dry basis.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates primarily to a water-based ink recording sheet suitable for drawing by a computer-driven image output device, and in particular to a sheet for overherad projectors (OHP). .

BACKGROUND OF THE INVENTION As sheets for over-the-top projectors (OHP), single polyester films or matted polyester films coated with a matting agent such as silicon dioxide have been used for some time.

In the early days, images were formed on OHP sheets by copying printed matter or hand-drawn manuscripts using a copying machine, or by directly drawing on them.

In recent years, as the use of OHP has increased, OHP is being
A method of outputting a desired image directly onto a HP sheet is becoming popular.

Methods of drawing on OHP sheets using a computer-driven image output device include thermal transfer method, sublimation thermal transfer method,
There are various methods such as electrostatic method, impact method, and inkjet method. Of these, inkjet method is characterized by low noise, high speed printing, easy color printing, and low running cost. These two are of high importance because they have advantages such as being cheap and requiring no development or fixing.

When using the inkjet method, oil-based ink or water-based ink is used. If oil-based ink is used, OHP sheets made of conventional polyester single film or matte polyester film are used. However, when using water-based ink, such OHP
This is inconvenient because the paper sheet lacks ink receptivity. Since most of the currently popular computer-driven image output devices use water-based jet ink, there is an urgent need to develop OHP sheets suitable for this.

OHP sheets that accept water-based jet inks include those in which a hydrophilic film layer made of a water-soluble polymer substance is provided on a transparent film base material (Japanese Patent Application Laid-Open No. 60-224578), Those coated with an acrylic acid polymer (Japanese Patent Application Laid-Open No. 61-24493), those coated with an adhesive containing a super absorbent polymer on a transparent film base material, and coated with transparent fine particles. (Japanese Unexamined Patent Publication No. 61-24494), a liquid absorbing layer and a liquid permeable surface layer provided in this order on a transparent film base (Japanese Unexamined Patent Publication No. 61-78687), a transparent film base material A transparent film base material is provided with a wood-loving coating layer made of a water-soluble polymeric substance, and fine irregularities are formed on the surface of the wood-philic coating layer (Japanese Unexamined Patent Publication No. 127386/1986). An ink-receiving layer containing a reaction product of polyalkylene oxide and an incyanate compound is provided (Japanese Patent Application Laid-Open No. 61-32787), and a coating agent consisting of polyvinyl alcohol and a matting agent is applied to a transparent film base material. A coated sheet (Japanese Unexamined Patent Publication No. 82-32079) has been proposed. Problems to be Solved by the Invention Characteristics required for an OHP sheet suitable for water-based jet ink include: ■ Surface coating layer and base High adhesion to film.

■ Blocking should not occur even when stored in a stacked state.

■High transparency; ■ Good drying and absorbency of water-based jet ink, ■The ink does not fade after drawing, ■ The resulting image is uniform; ■ Fingerprints are difficult to adhere to, ■ Good storage stability.

etc. can be mentioned.

Conventional OHP sheets are made of single polyester film or polymerized polyester film.

As mentioned above, since it does not accept water-based ink, the resulting image will run or easily come off due to friction.

On the other hand, OHP sheets for water-based jet inks, in which a liquid-absorbing layer made of a water-soluble polymer substance is formed on a transparent film base material such as a polyester film, have a water-based ink-receptive ability, so they are different from conventional single polyester sheets. Although it is significantly superior to OHP sheets made of film or matte film, it does not meet all of the above-mentioned required characteristics, and further improvements have been desired.

The present inventors have conducted extensive research to obtain a highly practical water-based jet ink recording sheet (particularly an OHP sheet) that has the above-mentioned required characteristics, and have decided to apply chitin or chitosan for this purpose. After many attempts, the present invention was completed.

Means for Solving the Problems, That is, the aqueous ink recording sheet of the present invention has a coating layer (2) of a composition containing at least chitin or/and chitosan on at least one side of a transparent polymer film (1). It is something that has been established.

The present invention will be explained in detail below.

In the present invention, a transparent polymer film (1) is used as the base film.

Polymer films (1) for this purpose include polyester films, polypropylene films, polycarbonate films, polyvinyl chloride films, and polyvinylidene chloride films.

Polyamide film, polystyrene film, polysulfone film, polyphenylene oxide film, polymethyl methacrylate film, polyimide film, polyvinyl alcohol or vinyl alcohol copolymer film, regenerated cellulose film,
Single layer films (sometimes multilayer films) such as etherified or esterified cellulose films are used;
In the case of synthetic resin films, biaxially stretched films are often used to increase strength and dimensional stability.

The visible light transmittance of the polymer film (1) is 75% or more,
In particular, 80% or more is suitable, and the thickness of the polymer film (1) is about 12 to 150 ILm, especially 25 to 120 ILm.
gra level is appropriate.

A coating layer (2) of a composition containing at least chitin and/or chitosan is provided on at least one side of the polymer film (1).

Chitin is a type of polysaccharide consisting of 7-minosaccharides with a molecular weight of about 20,000 to 500,000, and is composed of acetylated D
- It consists of a linear molecule in which glucosamine groups are bonded with β-14. Typically, the shells of crustaceans such as crabs and shrimp are crushed and treated with dilute hydrochloric acid to remove calcium carbonate.
It can be obtained by treating it with a concentrated alkaline solution to remove proteins and other impurities, and if necessary, dissolving it in 40% hydrochloric acid and immediately precipitating it. (Chemistry Dictionary 2, reduced edition, published by Kyoritsu Publishing Co., Ltd.

The 26th edition of the reduced edition was published on October 15, 1981.

(See pages 745-746) Chitosan is a basic polysaccharide composed of glucosamine (2-7mino D-glucose) with a molecular weight of approximately 20,000 to 500,000, and is obtained by heating chitin with a concentrated alkali. be. (Encyclopedia of Chemistry 2, reduced edition, published by Kyoritsu Shuppan Co., Ltd., October 15, 1981, 26th edition of reduced edition, 75
(See page 4) In the present invention, chitin and chitosan may be used alone or in a mixture of the two at any ratio, but the weight ratio of chitin and chitosan is 5:95.
A mixture of ~95:5 is the most balanced for purposes of this invention.

In addition, water-soluble polymer (
Polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polyacrylate, polyvinyl methyl ether, vinyl methyl ether/maleic anhydride copolymer, polyethylene glycol, polyethylene imine, acrylic resin or polyester resin with water-soluble groups introduced, methyl cellulose However, water-dispersible polymers (synthetic resin emulsions, etc.) may be blended.

In this case, the combined ratio of water-soluble polymer or water-dispersible polymer is 1 part by weight of chitin or/and chitosan.
．． 5 parts by weight or less, preferably 1 part by weight or less, even 0
．． It should not exceed 7 parts by weight.

Formation of the coating layer (2) of the composition containing chitin or/and chitosan on the polymer film (1) involves dissolving chitin or/and chitosan in an acidic aqueous solution such as an acetic acid aqueous solution, a lactic acid aqueous solution, a citric acid aqueous solution, etc. The solution is applied to the polymer film (1) and dried. in this case.

Fillers, surfactants, plasticizers, and other additives may be added to the coating liquid to the extent that they do not cause any problems.

The thickness of the coating layer (2) is about 1 to 30 pm on a dry basis,
In particular, 2 to 20 IL layers is appropriate; if it is less than 1 layer, the ability to accept water-based ink will be insufficient, and even if it exceeds 30 layers, the ability to accept water-based ink will not rise above a certain limit;
It has the disadvantage of slow drying during production and is disadvantageous in terms of cost since chitin-aged chitosan is expensive.

When forming the coating layer (2) of the composition containing chitin or/and chitosan on the polymer film (1),
A treatment for removing the water repellency of the polymer film (1), which is the base film, in order to improve the adhesion with the coating layer (2).

For example, surface treatments such as corona discharge treatment, flame treatment, and plasma treatment, coating of surfactants, and anchoring with adhesives such as incyanate adhesives may be performed.
A surfactant may be added to the side of the coating layer (2) forming the aqueous ink receiving layer to lower the surface tension.

FIG. 1 is a sectional view showing an example of the water-based ink recording sheet of the present invention, in which a coating layer (2) of a composition containing chitin and/or chitosan is coated on one side of a polymer film (1).
) is provided.

FIG. 2 is a cross-sectional view showing another example of the water-based ink recording sheet of the present invention, in which a coating layer (2) of a composition containing chitin or/and chitosan is coated on both sides of a polymer film (1). This shows the case where (2) is provided.

Although it is cheaper to provide the coating layer (2) of the composition containing chitin or/and chitosan on both sides of the polymer film (1) than to provide it on one side,
This is advantageous in terms of improving curling properties.

The thickness of the sheet, in which the coating layer (2) of the composition containing chitin or/and chitosan is provided on at least one side of the polymer film (1), is suitably about 10 to 150 grs, particularly about 15 to 100 grs. Also, care should be taken so that the light transmittance of the sheet is 80% or more.

The water-based ink recording sheet of the present invention having the above configuration is as follows:
It is equipped with a water-based inkjet printer or plotter and is useful as a sheet for drawing according to instructions from a computer, particularly as an OHP sheet, and also useful as a second original drawing. It is also useful as a drawing sheet for an x-y plotter or the like equipped with a water-based pen. Since the recording sheet of the present invention is receptive to water-based ink, in addition to automatic drawing, it is possible to copy printed matter using a copying machine as in the past, to add a kitten operation using water-based ink, or to draw by hand. You may perform only the operation.

Function When the water-based ink recording sheet of the present invention is used for purposes such as OHP sheets, the coating layer (2) of the composition containing chitin or/and chitosan is coated with the polymer film (1).
), the coating layer (2) side is placed toward the water-based jet ink ejection side of the output device (printer or plotter). When plotting with an X-Y plotter or the like, draw on the coating layer (2) side with a water-based pen.

The composition coating layer (2) containing chitin or/and chitosan receives water-based ink and quickly dries the received ink.

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

Hereinafter, "parts" refer to parts by weight.

Example 1 A polyester film with a thickness of 75 pot layers was used as the polymer film (1), and a coating solution having the following formulation was applied to one side of the film and dried with hot air at 80°C. The thickness of the obtained coating layer (2) was 15 cm.

1 88 parts of water (Chitin and chitosan manufactured by Nanyo Kasei Co., Ltd. were used.) Example 2 A polyester film with a thickness of 75 JAII was used as the polymer film (1), and one side of the film was previously subjected to corona discharge treatment. After applying the coating solution to a surface tension of 30 d1ne/am, a coating solution having the following formulation was applied to the treated surface and dried with hot air at 80°C. The thickness of the obtained coating layer (2) was 5 parts.

Comparative Example 1 A polyester film with a thickness of 75JL11 was used as the polymer film (1), and one side of the film was coated with polyvinyl alcohol (degree of polymerization 1000, degree of saponification 88 mol%) and polyvinylpyrrolidone (degree of polymerization 400) at a weight ratio of 5. : Apply a coating solution consisting of a 5% by weight aqueous solution of the mixture of 5 and heat at 80°C.
It was dried. The thickness of the obtained coating 1f 1 layer was 20 JLt
It was a.

Regarding the OHP sheets obtained in Examples 1 to 2 and Comparative Example 1, the adhesion of the coating layer to the base film,
In addition to examining the transparency (total light transmittance), blocking property and fingerprint adhesion at 81 layers, water-based ink for jet printers was dropped onto these OHP sheets, and the drying time of the water-based ink, fading property of the ink, Friction resistance and image uniformity were investigated.

The results are shown in the $1 table.

<Measurement and Evaluation Conditions> Adhesiveness was determined by making gobbles at 1 mm intervals on the coated layer with a cutter, pressing cellophane adhesive tape on the tape, and then peeling it off vigorously to see if the coated layer peeled off.

The total light transmittance was determined by using a two-spectrophotometer to determine the transmittance of light in the visible wavelength range.

The blocking property was measured by stacking 10 OHP sheets and applying a pressure of 0.5 kg/cm from above and below at 20°C and 65°C.
% RH or 30°C, 80% RH 7
Judgment was made based on the presence or absence of blocking when left for days.

Fingerprint adhesion was determined by holding the OHP sheet with a finger and visually determining the presence or absence of fingerprints.

The ink drying time was determined by touching the ink with a finger over time after dropping the water-based ink and checking whether the ink was transferred to the finger.

The fading property of the ink was evaluated by comparing the color of the original ink and the color of the ink 7 days after printing.

Table 1 Example 3 Example 4 Example 5 Examples 3 to 5 A polyester film with a thickness of 75 mm was used as the polymer film (1), and both sides of the film were preliminarily coated with an incyanate adhesive on a dry basis. A coating liquid having the following formulation was applied thereon and dried at 80°C. The film thickness of the obtained coating layers (2) and (2) was 15 g on both sides.

The performance of the OHP sheets obtained in Examples 3 to 5 above was examined in the same manner as in Example 1. The results are shown in Table 2.

Table 2 Effects of the Invention The aqueous ink recording sheet of the invention has a film-forming ability on at least one side of the polymer film (1) as a base film, and has good transparency.

A coating layer of a composition containing chitin and/or chitosan that has high adhesive strength with the film (1) and has good water-based ink receptivity and is resistant to moisture absorption (
2), it has all the characteristics required as a sheet for drawing by a computer-driven image output device, especially as an OHP sheet.

In other words, it has the ability to reliably accept water-based jet ink (water-based jet ink receptivity), the ability to quickly dry the received jet ink (quick-drying ability), and there is no risk that the water-based jet ink display area will erase due to friction etc. after drying. The resulting image is uniform (image uniformity), and the ink is resistant to fading (fading resistance).

In addition, the chitin and/or chitosan layer forming the coating layer (2) has water-based ink receptivity even in a thin layer, and does not cause blocking even when laminated (blocking resistance).
It prevents curling (curling resistance), and fingerprints do not stick easily to it, so fingerprints do not appear when projected on OHP (fingerprint adhesion prevention).

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of the water-based ink recording sheet of the present invention. FIG. 2 is a sectional view showing another example of the water-based ink recording sheet of the present invention. (1)...Polymer film, (2)...Coating layer of a composition containing chitin or/and chitosan. Figure 1. Patent applicant: Fujimori Kogyo Co., Ltd. Figure 2 '1 '1

Claims (1)

[Claims] 1. On at least one side of the transparent polymer film (1),
A water-based ink recording sheet comprising a coating layer (2) of a composition containing at least chitin and/or chitosan.