JPH0478570A - Recording sheet - Google Patents

Abstract

PURPOSE:To obtain a recording sheet holding light perviousness, having sufficient ink absorbability and imparting a recording image having excellent sharpness by adding a fluorine type surfactant to the first and second specific ink receiving layers. CONSTITUTION:The ink receiving layer constituting a recording sheet consists of the first and second ink receiving layers. The first ink receiving layer is based on polyvinyl pyrrolidone and contains a fluorine type surfactant. The compounding ratio of polyvinyl pyrrolidone is pref. 30 wt.% or more and the addition amount of the fluorine type surfactant is pref. 0.01-5 wt.%. The second ink receiving layer is based on polyvinyl butyral, polyvinyl pyrrolidone and/or polyethylene oxide and contains the fluorine type surfactant. The compounding ratio of polyvinyl butyral and polyvinyl pyrrolidone and/or polyethylene oxide is pref. 6:4 - 1:9 and the addition amount of the fluorine type surfactant is pref. 0.01-5 wt.%.

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. The present invention relates to a recording sheet suitable for observation through transmission with an optical device.

(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 in order 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 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 includes a first ink receiving layer containing polyvinylpyrrolidone as a main component, polyvinyl butyral, and polyvinylpyrrolidone and/or polyethylene oxide on at least one side of a base material. The recording sheet is characterized in that second ink-receiving layers are sequentially laminated, and the first ink-receiving layer and the second ink-receiving layer contain a fluorine-based surfactant.

The base material constituting the recording sheet of the present invention may be a film made of a plastic having excellent translucency such as polyethylene terephthalate, diacetate, triacetate, acrylic polymer, cellophane, celluloid, polyvinyl chloride, polycarbonate, or polyimide; A plate, a glass plate, etc. can be used, and the material is appropriately selected depending on various conditions such as the recording purpose, the use of the recorded image, and whether good adhesion with the ink-receiving layer provided thereon can be obtained. .

Next, the ink receiving layer will be explained. The ink-receiving layer constituting the recording sheet of the present invention is composed 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.In the present invention, the first and second ink-receiving layers contain a fluorine-containing surfactant, and in particular, the ink-receiving layer is coated with an ink-receiving layer. It aims to improve absorbency, bleed resistance, etc., and obtain clear recorded images.

First, the first ink receiving layer provided on the base material is
It has a structure in which polyvinylpyrrolidone is the main component and a fluorine-based surfactant is added. Bolivinino in the nuclear layer? The blending ratio of pyrrolidone is preferably 30% by weight or more, particularly preferably 60 to 80% by weight. Further, the amount of the fluorosurfactant added can be 5% by weight or less to obtain a sufficient effect, and is preferably 0.01 to 5% by weight.

The fluorine-based surfactant used in the first ink-receiving layer may be any type of anionic, cationic, nonionic, or betaine type, and conventionally known ones can be used. For example, perfluorinated surfactants can be used. Preferred are alkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl quaternary ammonium iodides, perfluoroalkyl polyoxyethylene ethanol, perfluoroalkyl alkoxylates, fluorinated alkyl esters, etc., and these fluorine-based The surfactant is, for example, 3M
It is sold under the product name Florado by the company.

In addition, resins that are used together with polyvinylpyrrolidone as needed in the first ink receiving layer include acrylic, methacrylic, amide, vinyl chloride, vinyl acetate, and vinyl that are compatible with polyvinylpyrrolidone and have film properties. A homopolymer or copolymer of alcohol or the like is used, and among them, a homopolymer or copolymer of vinyl chloride, vinyl acetate, or vinyl alcohol is preferred, and at least one selected from these polymers and polyvinylpyrrolidone are used. When used in combination, the effect of compensating for water resistance, which is a weak point of polyvinylpyrrolidone, can be obtained. The molecular weight of the polyvinylpyrrolidone used is not particularly limited, but it preferably has a value of 30 to 90, particularly preferably 60 to 90, as expressed by Fikentscher's viscosity formula.

Next, the second ink-receiving layer contains polyvinyl butyral, polyvinylpyrrolidone and/or polyethylene oxide as main components, and has a structure in which a fluorine-based surfactant is added.

As described above, the second ink-receiving layer is provided on the first ink-receiving layer in order to overcome the poor water resistance, which is a weak point of the first ink-receiving layer. This second 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, which has better ink-absorbing properties, for reabsorption. This makes it possible to prevent ink from bleeding in the second ink-receiving layer.

In the second ink-receiving layer, the blending ratio of polyvinyl butyral and polyvinylpyrrolidone and/or polyethylene oxide is preferably 6:4 to 1:9 (weight ratio), and the amount of the fluorosurfactant added is: As with the first ink-receiving layer, a sufficient effect can be obtained with a content of 5% by weight or less, and a content of 0.01 to 5% by weight is preferred.

The polyvinyl butyral used in the second ink-receiving layer is preferably one with a molecular weight of about 10,000 to 500,000 and a butyralization degree of 50 to 80 mol%, and the polyethylene oxide has an average molecular weight of 50,000 to 50,000 or more. Preferably. In addition, as polyvinylpyrrolidone, the first
As in the case of the ink-receiving layer, the molecular weight is not particularly limited, but it preferably has a value of 30 to 90, particularly preferably 60 to 90, as expressed by Fikentscher's viscosity formula. Furthermore, the fluorine-based surfactant used in the first ink-receiving layer can also be applied to the second ink-receiving layer. Furthermore, if necessary, a resin such as polyvinyl chloride, polyvinyl acetate, polyvinyl alcohol, or polyamide may be used in the second ink-receiving layer in addition to the resin constituting the second ink-receiving layer. .

The ink-receiving layer in the present invention, regardless of whether it is the first or second ink-receiving layer, may contain melamine formaldehyde resin, urea formaldehyde resin, or glyoxal in order to provide water resistance and prevent ink from bleeding for inkjet printers as necessary. A water-resistant agent such as zirconium ammonium carbonate or the like can be added.

In addition, in order to further enhance the recording properties of the recording sheet and improve the blocking resistance, for example, silica, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, barium sulfate, aluminum silicate, synthetic zeolite, alumina, oxidized Fillers such as zinc, lithopone, satin white, etc. may be dispersed in both ink-receiving layers.

Furthermore, in order to further improve the productivity, recording properties, and storage stability of recording sheets, various additives such as dispersants, fluorescent dyes, pH adjusters, antifoaming agents, lubricants, and preservatives are added to both inks. They can also be mixed in layers. In the case of a translucent recording sheet, these additives need to be added to an extent that does not impair translucency.

In order to provide the first and second ink-receiving layers on the base material, a coating solution prepared by dissolving or dispersing the material forming the ink-receiving layer in a suitable solvent is prepared using a roll coating method, a blade coating method, spray coating method,
A method such as applying by a method such as an air knife coating method or a Ronto coating method and drying the resultant method, or a method of applying a homogeneous mixture of the materials capable of forming the above-mentioned ink-receiving layer onto the above-mentioned base material by real-melting. A method of forming an ink-receiving layer by laminating layers by a coating method, a laminate coating method, etc. can be applied.

The thickness of the ink receiving layer provided in the recording sheet of the present invention is preferably about 5 to 10 μm for the first ink receiving layer;
Further, the second ink receiving layer has a thickness of 2 to 10 μm, especially 5 μm.
The following is desirable. If the thickness of the ink-receiving layer is too thick, the light transmittance (in-line transmittance) decreases, and if it is too thin, the ink absorbency decreases, 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 applied to uses other than conventional surface image observation, such as color separation plates when creating positive plates, or CMF used in color displays such as liquid crystals.

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, the first ink-receiving layer paint is applied and dried to form the first ink-receiving layer with a thickness of 10 μm, and then the 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.

(1) First ink-receiving layer (2) Second ink-receiving layer (2) Second ink-receiving layer Example 4 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 Example 3 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 the second ink-receiving layer.

(2) Second Ink Receptive Layer 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 a coating material for the first ink receiving layer.

Comparative Example 1 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 coating material for the first ink-receiving layer, and the second ink-receiving layer was not provided.

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.

Comparative Example 4 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 second ink-receiving layer coating material.

The recording sheets obtained in Examples 1 to 4 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, manufactured by NEC Corporation), color printing was performed, and ink absorption, image quality, and water resistance were evaluated.

The evaluation results are 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 △.

The printed sample was set on an overhead projector (Ricoh OHP wide, manufactured by Ricoh Co., Ltd.), the image was projected onto a screen, and its sharpness was visually judged. Those with good and clear projected images were designated as ×, those with poor O1 were designated as ×, and those in the middle were designated 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. A sample with no problems at all was graded as ○, a sample where the surface was softened or elution of the ink receiving layer components was clearly observed was graded as x, and an intermediate grade was graded as Δ.

Table I (Effects of the Invention) Since the present invention has the above configuration, there is no ink bleeding in images recorded by an inkjet printer.
In addition, the ink fixability is good, so even if you touch the recorded area with your finger, the ink will not stick to your finger. Even if it is spilled on the recording sheet according to the present invention, there is no risk that the recorded image will become unclear or it will peel off.

Claims (3)

[Claims] (1) A first ink-receiving layer containing polyvinylpyrrolidone as a main component, a second ink-receiving layer containing polyvinyl butyral, and polyvinylpyrrolidone and/or polyethylene oxide are sequentially laminated on at least one side of the base material. A recording sheet characterized in that the first ink receiving layer and the second ink receiving layer contain a fluorine-based surfactant. (2) The recording sheet according to claim 1, wherein the base material is translucent. (3) The first ink-receiving layer is characterized in that, in addition to the polyvinylpyrrolidone, the first ink-receiving layer contains at least one selected from the group consisting of vinyl chloride, vinyl acetate, and polyvinyl alcohol homopolymers or copolymers. Claim 1
and the record sheet described in 2.