JPH02243380A - Recording sheet - Google Patents

Abstract

PURPOSE:To obtain a recording sheet for ink jet recording excellent in visibility of recorded image by providing, through successive lamination, one side of a translucent base material with a first ink receptive layer containing a specific quantity or more of polyvinyl pyrrolidone and a second ink receptive layer containing a specific quantity or more of polyethylene oxide. CONSTITUTION:Polyethylene terephthalate excellent in translucency, etc., are used as translucent base material constituting a recording sheet. An ink receptive layer is composed of two layers of a first ink respective layer and a second ink receptive layer. The first ink receptive layer provided on the translucent base material is required to contain 30wt.% or more of polyvinyl pyrrolidone. The second ink receptive layer contains 40wt.% or more of polyethylene oxide. The second ink receptive layer is provided on the first ink receptive layer to remove inferior water resistance being the weak point of the first ink receptive layer. Thus, it is possible to prevent ink from blotting in the second ink receptive layer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording sheet suitable for inkjet printers, and more specifically, it has excellent translucency, and the recorded image can be transmitted to an overhead projector (hereinafter referred to as OHP), etc. This invention relates to a recording sheet that is passed through for observation with an optical instrument.

(Prior 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 are binders, dyes, solvents, additives, etc. dissolved in water.

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

On the other hand, with the shift to color inkjet printers,
There is an increasing demand for recording on a transparent recording medium and using it as an OHP recording sheet.

However, transparent recording sheets are usually made of plastic film, which is hydrophobic and does not absorb any ink for inkjet printers, so ink recorded directly on it does not dry easily and cannot be rubbed with your fingers. If they are placed on top of each other, the recorded area will become dirty and will not be of practical use.

As a countermeasure to this problem, in order to improve the receptivity to water-based ink, that is, the absorption of ink, the main ingredient is polyvinyl alcohol, and glycerin, lithium chloride, etc.
For inkjet printer inks such as starch, gelatin, hydroxyethyl cellulose, or carboxymethyl cellulose, it has been proposed to provide an aqueous ink-receiving layer containing a wettable material on a light-transmitting substrate. Even if the layer satisfies ink absorbency, the surface becomes sticky and blocking occurs when multiple sheets are stacked, and depending on the material, the translucency may decrease. It had a

(Problems to be Solved by the Invention) In view of the above-mentioned circumstances, the present invention has been developed to provide a material that maintains transparency, has sufficient ink absorption, and has excellent clarity of recorded images when used for OHP. The present invention aims to provide a recording sheet for inkjet recording.

(Means for Solving the Problems) The present invention has been made to solve the above problems, and provides a first ink containing 30% by weight or more of polyvinylpyrrolidone on at least one side of a transparent substrate. a receptor layer;
A second material containing 40% by weight or more of polyethylene oxide
This is a recording sheet characterized in that an ink-receiving layer and an ink-receiving layer are sequentially laminated.

The light-transmitting substrate constituting the recording sheet of the present invention includes polyethylene terephthalate, diacetate, triacetate, acrylic polymer, cellophane, which has excellent light-transmitting properties,
Films, plates, glass plates, etc. made of plastics such as celluloid, polyvinyl chloride, polycarbonate, and polyimide can be used for recording purposes, recording images, and good adhesion to the ink-receiving layer provided above. The selection is made as appropriate depending on various conditions such as whether or not the characteristics can be obtained.

Next, the ink-receiving layer will be explained. The ink-receiving layer constituting the recording sheet of the present invention consists of two layers: a first ink-receiving layer and a second ink-receiving layer. this is,
Polyvinylpyrrolidone used for the first ink-receiving layer has excellent ink absorption and fixing properties, but there are concerns about water resistance. This is because an ink-receiving layer is provided to cover the first ink-receiving layer.

First, the first ink-receiving layer provided on the light-transmitting substrate needs to contain polyvinylpyrrolidone in an amount of 30% or more. That is, in the first ink-receiving layer, the weight ratio of polyvinylpyrrolidone to other resins and additives is 30:0 to 100:0, preferably 60:40 to 80:20. Here, as other resins, single or copolymers of acrylic, methacrylic, amide, vinyl chloride, vinyl acetate, vinyl alcohol, etc., which are compatible with polyvinylpyrrolidone and have film properties, are used. Single or copolymers of vinyl, vinyl acetate, and vinyl alcohol are preferred, and by using a combination of at least one selected from these polymers and polyvinylpyrrolidone, it is possible to compensate for the water resistance, which is the weak point of polyvinylpyrrolidone. You can get the effect that you can. The molecular weight of the polyvinylpyrrolidone used is not particularly limited, but the valence expressed by the Fikkentsch viscosity formula is 30.
-90 is preferable, and 60-90 is particularly suitable.

The second ink-receiving layer consists of 40% polyethylene oxide.
The content is at least 60 to 90% by weight. As mentioned above, the second ink-receiving layer is formed on the first ink-receiving layer in order to overcome the weak point of the first ink-receiving layer, which is poor water resistance.
The ink-receiving layer is provided on top of the ink-receiving layer. This second
The ink-receiving layer has the function of directly receiving and quickly absorbing ink during printing, and transferring the ink to the first ink-receiving layer having better ink absorption properties and reabsorbing the ink, This can prevent ink from bleeding in the second ink-receiving layer.

Binder resins that can be used in combination with polyethylene oxide include polyvinyl butyral, polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, and polyamide. In order to fully exhibit the above-mentioned functions, it is preferable that polyethylene oxide and polyvinyl butyral coexist in the second ink-receiving layer. In this case, the weight ratio of polyethylene oxide and polyvinyl butyral is suitably 4:6 to 9:1. Further, it is preferable to use polyethylene oxide having an average molecular weight of 50,000 or more, and polyvinyl butyral having a molecular weight of about 10,000 to 500,000 and a degree of butyralization of 50 to 80 mo1%.

The ink receiving layer in the present invention, regardless of whether it is the first or second receiving layer, is made of melamine formaldehyde resin, urea formaldehyde resin, glyoxal, zirconium ammonium carbonate, etc. in order to provide water resistance and prevent ink from bleeding for inkjet printers. It is preferable to add a water resistant agent.

In addition, in order to further enhance the recording properties of the recording sheet and improve the blocking resistance, additives such as silica, sauce, talc, diatomaceous earth, calcium carbonate, calcium sulfate, and sulfuric acid may be added to an extent that does not impair the transparency of the recording sheet. Fillers such as barium, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithopone, satin white, etc. may be dispersed in both ink-receiving layers.

Furthermore, in order to further improve the productivity, recording characteristics, storage stability, etc. of the recording sheet, dispersants, fluorescent dyes, PHOi
Various additives such as conditioners, antifoaming agents, lubricants, and preservatives can also be mixed in both ink-receiving layers. These additives are also added to an extent that does not impair the transparency of the recording sheet.

To provide the first and second ink-receiving layers on the transparent substrate, a coating solution prepared by melting or dispersing the material for forming the ink-receiving layer in an appropriate solvent is coated using a roll coating method or a blade coating method. A method of coating by a method such as a coating method, a spray coating method, an air knife coating method, a ronto coating method, etc. and drying it, or a method of uniformly mixing a mixture of materials capable of forming the above-mentioned ink receiving layer, A method of forming an ink-receiving layer by laminating the ink-receiving layer on the light-transmitting substrate by a hot-melt coating method, a laminate coating method, or the like can be applied.

The thickness of the ink-receiving layer provided in the recording sheet of the present invention is preferably about 5 to IO μm for the first ink-receiving layer, and 2 to 10 μm for the second ink-receiving layer, particularly preferably 5 μm or less.
If the thickness of the ink-receiving layer is too thick, the light transmittance (in-line transmittance) will decrease, and if it is too thin, the ink absorbency will decrease, which is not preferable.

The recording sheet of the present invention having the above-mentioned structure is provided with the first and second ink receiving layers laminated on at least one side, but they can be provided on both sides if necessary.

Since the recording sheet of the present invention has excellent translucency, its uses are not limited to OHP, but also those used for projection observation of recorded images onto a screen etc. using an optical device other than OHP such as a slide, and color printing. It can also be used for purposes other than conventional surface image observation, such as a color separation plate when creating a positive plate, or a CMF used in a color display such as a liquid crystal.

Furthermore, even if it is for OHP, recording means other than inkjet printers, such as PPC plate making by electrophotography, handwriting, etc., are also included in the application of the present invention.

(Examples) The present invention will be described in detail below according to Examples. Note that all parts represent parts by weight.

Example 1 A 100 μm thick polyethylene terephthalate film (Tetron Film S type, manufactured by Kijinsha) was used as a translucent base material, and a first ink-receiving layer paint and a second ink-receiving layer paint having the following compositions were applied. First, a first ink-receiving layer paint is applied and dried to form a 10 μm thick first ink-receiving layer, and then a second ink-receiving layer paint is applied thereon. - A recording sheet of the present invention was prepared by drying and providing a second ink-receiving layer with a thickness of 3 μm.

(1) First Ink-Receiving Layer Example 2 A recording sheet of the present invention was prepared in exactly the same manner as in Example 1, except that the following composition was used as the coating material for each ink-receiving layer.

(11 First ink-receiving layer (2) Second ink-receiving layer 1n-butanol (2) 90 parts of second ink-receiving layer Example 3 The following composition was used as a paint for the second ink-receiving layer. A recording sheet of the present invention was produced in the same manner as in Example 1 except for this.

Example 4 A recording sheet of the present invention was produced in exactly the same manner as in Example 1, except that the thickness of the second ink-receiving layer was 8 μm.

Example 5 A recording sheet of the present invention was prepared in exactly the same manner as in Example 1, except that a coating material with the following composition was used as a coating material for each ink-receiving layer.

(1) First ink-receiving layer (2) Second ink-receiving layer (2) Second ink-receiving layer Example 6 Example 1 except that the following composition was used as the paint for each ink-receiving layer. A recording sheet of the present invention was produced in exactly the same manner as described above.

(1) First ink-receiving layer comparative example 1 A comparison was made in exactly the same manner as in Example 1, except that the following composition was used as the paint for the first ink-receiving layer and the second ink-receiving layer was not provided. A recording sheet was created for the purpose.

Comparative Example 2 A comparative recording sheet was prepared in exactly the same manner as in Comparative Example 1, except that a coating material with the following composition was used as the first ink-receiving layer coating material.

Comparative Example 4 A comparative recording sheet was prepared in the same manner as in Example 1, except that a coating material with the following composition was used as the second ink-receiving layer coating material.

Comparative Example 3 A comparative recording sheet was prepared in exactly the same manner as in Example 1, except that a coating material with the following composition was used as the first ink-receiving layer coating material.

The recording sheets obtained in Examples 1 to 6 and Comparative Examples 1 to 4 were cut into A4 size, and printed on an inkjet printer (P.
C-PR801, manufactured by NEC Corporation) and inkjet printer ink (PC-PR801, NE (manufactured by : Corporation)
Color printing was carried out using the following, and ink absorption, image quality, and water resistance were evaluated.

The evaluation results are as shown in Table 1, and it was confirmed that the recording sheet of the present invention has excellent ink absorbency and can produce good images. The evaluation method for each item in Table -■ is as follows.

Ink absorption: After printing, the state of the ink remaining in the form of beads on the printed surface was visually evaluated. O is the one that doesn't leave any ink.

When the ink became bead-like and a large amount remained, it was marked as ×, and when it was in the middle, it was marked as △.

Image quality: The sample after printing was placed on an overhead 7-domain projector (Ricoh OHPwide, manufactured by Ricoh Co., Ltd.), the image was projected onto a screen, and its sharpness was visually judged. Good and clear projected images were rated as ◯, those that were poor were rated as ×, and those in the middle were rated as Δ.

Water resistance: Running water was applied to the surface of the second ink-receiving layer for 5 seconds, and the state of the coated surface was then observed. Those with no problems at all were designated as 01. Those where the surface was softened or elution of the ink receiving layer components was clearly observed were designated as ×, and those in the middle were designated as Δ.

Table - ■ (Effects of the invention) Since the present invention has the above-described configuration, there is no ink bleeding in images recorded by an inkjet printer.
In addition, the ink has good fixation properties, so even if you touch the recorded area with your finger, the ink will not stick to your finger.Furthermore, it has good water resistance, so it can be easily touched with wet hands, or exposed to water, tea, etc. Even if spilled on the recording sheet according to the present invention, there is no risk that the recorded image will become unclear or come off.

Patent applicant: Tomoekawa Paper Mills Co., Ltd.

Claims (1)

[Scope of Claims] 1) a first ink-receiving layer containing 30% by weight or more of polyvinylpyrrolidone on at least one side of a transparent substrate;
A second material containing 40% by weight or more of polyethylene oxide
What is claimed is: 1. A recording sheet comprising: an ink-receiving layer; and an ink-receiving layer. 2) A claim characterized in that the first ink-receiving layer is made of a combination of polyvinylpyrrolidone and at least one selected from vinyl chloride, vinyl acetate, and vinyl alcohol alone or as a copolymer. Record sheet described in item 1. 3) The recording sheet according to claim 1 or 2, wherein the second ink receiving layer is made of a combination of polyvinyl butyral and polyethylene oxide.