JPS60220750A - Material to be recorded - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording material used for recording with ink, and particularly to a recording material that has particularly excellent light transmittance and ink absorbency and is suitable for inkjet recording.

Common methods for recording using recording liquid (ink) include fountain pens, water-based ballpoint pens, felt-tip pens, etc., and recording methods that have recently attracted attention include An example is an inkjet recording method in which ink droplets are generated and the droplets are attached to a recording material to perform recording.

This inkjet recording system is characterized by the fact that it generates little noise during recording, and can perform high-speed recording and multicolor recording.

In such recording methods, water-based inks are mainly used from the viewpoint of safety and recording suitability.

The recording material used in the above recording method is as follows:
Traditionally, regular paper has been used. However, as the performance of inkjet recording devices improves, such as faster recording speeds and multicolor recording, more advanced properties are required of recording materials used in inkjet recording methods. .

In other words, in order to obtain high resolution and high quality recorded images, the recording material used in the inkjet recording method must 1) absorb ink as quickly as possible, and 2) absorb the ink as quickly as possible, and 2) absorb , the ink deposited later will not flow onto the ink dots deposited earlier.

3) The diameter of the ink dot should not be larger than necessary, 4) The shape of the ink dot should be close to a perfect circle, and the area around it should be smooth, 5) The density of the ink dot should be high, and the area around the dot should not be blurred, 6) It is necessary that the ink satisfies required performance, such as having excellent color development.

As described above, while images recorded by inkjet recording are used for surface image observation, there is a growing demand for a recording material that allows images recorded by inkjet recording to be used for purposes other than surface image observation.

Applications other than surface image observation include: 1. Projecting recorded images onto a screen using an optical device such as a slide or OHP (overhead projector) for observation, contact printers, and printing boards for printed circuit boards (photomasks). , color separation plates for making positive plates for color printing, CMF (color mosaic filters) for liquid crystal color displays, etc.

When a recorded image is used for the above-mentioned surface image observation, the diffused light of the recorded image is mainly observed, whereas with recording materials used for these purposes, the recorded image is mainly observed. The transmitted light is observed or used for various purposes. Therefore, in addition to the above-mentioned required performance, the recording materials used for these applications must have sufficiently excellent translucency.
This is required.

However, a recording material that satisfies all of these required performances has not yet been known.

In particular, with regard to recording materials used for applications that utilize transmitted light from recorded images, there is no known material that simultaneously satisfies sufficient recording properties and translucency; for example, conventional translucent resins When a film or the like is used as a recording material for such purposes, although it has excellent translucency, it has poor ink absorbency, and when the recorded image is overlapped with paper etc. after recording, ink may transfer or the recorded image may The disadvantage was that it caused imitation scratches.

The present invention has been developed in view of these problems, and its purpose is to fully satisfy the above-mentioned required characteristics, to have particularly excellent ink absorbency and translucency, and to be suitable for uses other than surface image observation.
In other words, slide, OH, which utilizes the transmitted light of the recorded image.
The object of the present invention is to provide a recording material that can be used in optical equipment such as a contact printer and is suitable for inkjet recording.

The above object can be achieved by the following recording material of the present invention.

That is, the recording material of the present invention is a translucent recording material comprising a translucent base material and an ink absorbing layer provided on the base material, wherein the ink absorbing layer is Saponification degree 70-8
It is characterized by containing 0 mol% of partially saponified polyvinyl alcohol.

The translucent recording material of the present invention includes a translucent base material and an ink absorbing layer provided on the base material having a surface on which recording is performed during recording, that is, a surface that receives ink, The ink-absorbing layer is characterized by excellent ink-absorbing properties.

The base material of the recording material of the present invention may be a film or film made of a plastic having excellent translucency, such as polyester, diacetate, triacetate, acrylic polymer, cellophane, celluloid, polyvinyl chloride, polycarbonate, or polyimide. A plate, glass plate, etc. can be used.

The ink absorbing layer of the recording material of the present invention is a portion that receives and absorbs ink from the recording means of a recording device or recording device during recording.

In general, absorption of ink by a recording material is carried out by the ink adhering to the surface of the recording material entering fine voids within the structure of the recording material mainly through capillary action. Factors that greatly affect the ink absorption of such a recording material include the structure of the recording material and the physical properties of the materials that make up the recording material. That is, the structure of the recording material is such that the ink easily permeates, and the recording material has a suitable void volume to absorb and accommodate the ink, and furthermore, It is important that the material used has compatibility with the ink. Therefore, since the ink used is water-based, it is very important to use a wood-philic material for the part of the recording material that receives and absorbs the ink in order to obtain excellent ink absorbency. Effective.

The ink absorbing layer of the recording material of the present invention is mainly made of partially saponified polyvinyl alcohol that has excellent ink absorbability, can form a continuous film that is transparent, and has sufficient wood-philicity. It is formed using

The partially saponified polyvinyl alcohol that can form the ink absorption layer of the recording material of the present invention is a homopolymer of vinyl acetate, or a combination of vinyl acetate, vinyl chloride, ethylene, maleic acid, itaconic acid, etc. It can be obtained by saponifying a copolymer with a vinyl monomer such as acrylic acid to a predetermined degree of saponification with an acid or an alkali by a known method.

Partially saponified polyvinyl alcohol has different physical properties such as solubility in water, wood affinity, and secondary transition temperature depending on the degree of saponification (degree of saponification), and the ink absorbing layer formed by polyvinyl alcohol Ink absorbency also changes depending on its degree of saponification.

The degree of saponification of the partially saponified polyvinyl alcohol that can form the ink absorbing layer of the recording material of the present invention is preferably 70 to 90 mol%, more preferably 75 to 86 mol%. It is desirable that

That is, when the degree of saponification of polyvinyl alcohol is 70 mol% or less, the polyvinyl alcohol has low wood-philicity, and the ink absorbing layer formed thereby cannot obtain sufficient ink absorbency; If this is the case, the hydrogen bonds between the polymers become too strong, and the ink absorbency of the ink absorbing layer formed thereby decreases. Furthermore, inkjet recording inks generally contain polyhydric alcohols such as glycerin to prevent clogging due to evaporation of water from the ink, and if the degree of saponification is too high, these polyhydric alcohols Polyvinyl alcohol is undesirable because it becomes poorly compatible with the ink absorbing layer.Also, polyvinyl alcohol tends to change the crystalline state of the polymer and the entropic degree of freedom of molecules depending on temperature and humidity, and the ink absorbency changes along with these changes. .

Therefore, in order to obtain good ink absorbency within a sufficiently practical temperature and humidity range, it is preferable that the degree of saponification of polyvinyl alcohol is 75% to 86%.

The saponification degree here refers to the proportion of saponified vinyl acetate groups in the total vinyl acetate groups in the polymer (mol%).
This is shown in .

As described above, in the recording material of the present invention, the affinity of the ink absorption layer for water-based ink is increased due to the hydrophilicity of partially saponified polyvinyl alcohol, which is preferably used as a component for forming the ink absorption layer. In addition, since the unsaponified portion also has an affinity for the polyhydric alcohol contained in the ink, the ink can easily penetrate into the absorption layer.

Note that the degree of polymerization of the polyvinyl alcohol contained in the ink absorbing layer of the recording material of the present invention is not particularly limited, but is at least as high as possible to obtain good film formability, that is, about 300 or more. That's fine.

In addition to the above partially saponified polyvinyl alcohol, the ink absorbing layer of the present invention may contain, for example, starch, gelatin, casein, gum arabic, sodium alginate, carboxymethylcellulose-sulpyrrolidone, polyacrylic acid, sodium polyacrylate, Water-soluble polymers such as acrylamide and epoxy resins. It may also contain resins such as SBR latex, MBR latex, melamine resin, and phenol resin.

Furthermore, if desired, fillers such as finely divided silicic acid, clay, talc, diatomaceous earth, calcium carbonate, calcium sulfate, titanium oxide, and titanium oxide may be used as fillers, mainly to further enhance the ink absorption properties of the ink-absorbing layer. One or more inorganic pigments such as zinc, satin white, aluminum silicate, lithopone, alumina, zeolite, etc., and various additives such as dispersants, fluorescent dyes, pH adjusters, antifoaming agents, lubricants, preservatives, etc. It may be dispersed in the ink absorbing layer within a range that does not impair the predetermined light transmittance of the recording material.

The recording material of the present invention is prepared by dissolving or dispersing various materials capable of forming the above-mentioned ink absorbing layer in an appropriate solvent, and applying a coating liquid to the coating liquid using a roll coater method, a blade coater method, an air knife method, etc. It can be formed by various methods such as a coater method and a rod bar coater method, a method of coating on the above-mentioned base material and drying, a hot melt coating method, and the like.

The thickness of the ink absorbing layer of the recording material of the present invention after drying is usually about 1 to 100 μ, preferably 4
It is formed to have a thickness of about 50 μm.

If the thickness of the ink absorption layer is too thick, the light transmittance will decrease, and if the thickness of the ink absorption layer is too thin, the ink absorption will decrease, which is not appropriate.

On the other hand, in order for the recording material to be used for applications that utilize the transmitted light of images recorded on the recording material, such as optical equipment such as slides, OHPs, and contact printers, the recording material must have sufficient light transmittance. It has to be something.

For example, when observing a projected image of a recorded image using an OHP, which is a typical optical device, in order to obtain a clear and easy-to-see image with high contrast between recorded and non-recorded areas,
It is required that the non-recorded areas in the projected image be bright, that is, the in-line transmittance of the recording material must be at a certain level or higher.

In order to obtain an image suitable for the above purpose from the test using the OHP test chart, in other words, in the projected image of the test chart, the pitch width is 0.5 +u+ and the thickness is 0.2.
In order to be able to clearly distinguish the lines of the five layers, the in-line transmittance of the recording material needs to be 2% or more, and preferably, to obtain a clearer projected image, it needs to be 10% or more. .

Therefore, the translucent recording material referred to in the present invention is one in which the in-line transmittance of the recording material gold body, which is a combination of the translucent base material and the ink absorption layer, is 2% or more, preferably 105 or more. say.

In the present invention, the linear transmittance (T%) means that the light is incident on a sample, passes through the sample, passes through a light receiving side slit located on an extension of the incident optical path and is at least 8 cm away from the sample, and is detected. The spectral transmittance of the straight light received by the instrument is measured using, for example, a 323-type Hitachi self-recording spectrophotometer (manufactured by Hitachi, Ltd.), and from the measured spectral transmittance, the tristimulus value Y of the color is determined. This is a value calculated from the following equation using the Y value.

T=Y/Y.

T; Linear transmittance Y; Y value of sample Yo; Y value of blank Therefore, the linear transmittance referred to in the present invention is for straight light, and the linear transmittance of the recording material using the linear transmittance in the present invention is Light transmittance evaluation methods include diffuse transmittance (an integrating sphere is placed behind the sample to calculate transmittance including diffused light) and opacity (white and black backing is placed behind the sample). guess,
This method is different from the method of evaluating translucency using diffused light, such as (based on their ratio). The problem with devices that use optical technology is mainly the behavior of straight light, so when evaluating the translucency of the recording material to be used in these devices, it is necessary to It is especially important to measure the in-line transmittance.

The recording material of the present invention does not necessarily have to be colorless and transparent, and there is no problem even if it is a colored and transparent recording material.

In the recording material of the present invention as explained above, the hydrophilicity of partially saponified polyvinyl alcohol possessed by the ink absorbing layer increases the affinity of the ink absorbing layer for water-based ink. The absorbent layer has particularly excellent ink absorbency among the characteristics required for the recording material mentioned above.

Furthermore, the recording material of the present invention has sufficient light transmittance, enables high-speed printing and multicolor printing by inkjet recording, and allows the recorded image to be used for purposes other than surface observation.
In other words, slides and OHPs that utilize the transmitted light of recorded images.
It is very suitable as a recording material for use in optical equipment such as contact printers.

Hereinafter, the recording material of the present invention will be explained in more detail using Examples and Comparative Examples.

Example 1 A transparent, hydrophilically treated polyester film (manufactured by Ondai) with a thickness of too thick was used as the base material, and as an ink absorbing layer, polyvinyl alcohol (PVA) partially saponified to a degree of saponification of 80 mol% was used. A composition consisting of 8 parts by weight of 420H (manufactured by Kuraray Co., Ltd.) and 100 parts by weight of water was applied using a bar coater method so that the dry film thickness of the ink absorbing layer was 10%, and this was heated at 80°C for 10 minutes. The recording material of the present invention was obtained by drying under the following conditions and can be used in applications utilizing transmitted light of recorded images.

On-demand type inkjet recording head (ink discharge orifice diameter: 65 scales, piezo vibrator drive voltage: 75 V, Inkjet recording was performed using a recording device having a frequency of 2 KHz) to obtain a recorded image.

The thus obtained recorded images were tested for the following four items to evaluate the recording suitability of the recording material and the suitability for optical equipment.

(1) Ink fixability is measured by leaving the recorded matter at room temperature after inkjet recording, and measuring the time until the ink dries sufficiently without sticking to the finger when touching the recorded area with the finger. evaluated.

(2) Inno-dot concentration was measured for black dots using Sakura Microdensitometer PDM-5 (manufactured by Konishiroku Photo Industry Co., Ltd.) by applying JIS K 7650 to printed microdots.

(3) OHP suitability was measured as a representative example of the suitability of the recording material for optical equipment, and was determined by projecting the recorded image onto a screen using OHP and visually observing it. The OD (optical density) of the image is high, and the projection image with high contrast is clear and easy to see. ．．
Δ indicates that the lines of the 25-layer sander cannot be clearly distinguished; the non-recorded area is quite dark, the OD of the recorded image is quite low, and the lines of the 25-layer sandal cannot be clearly distinguished;
Alternatively, X indicates that the non-recorded area and the recorded image cannot be distinguished.

(4) In-line transmittance is measured to evaluate the light transmittance as one of the evaluations of the suitability of optical equipment. It was calculated from the spectral transmittance measured using a meter.

Furthermore, a comprehensive evaluation was made based on the above results. In the overall evaluation, those with excellent inkjet recording suitability, sufficient translucency, and suitability for optical equipment (0), and recording materials with sufficient recording suitability but long ink fixation time. Two types of evaluations were carried out: those that were unsuitable for use as an optical device, and those that lacked suitability for recording and optical equipment (X).

The obtained evaluation results are shown in Table 3.

Examples 2 to 7 and Comparative Examples 2 to 5 A 75 μm thick translucent surface-treated polyester film (manufactured by DuPont) was used as the base material, and the lii composition shown in Table 2 was used as the ink absorption layer. Each of these was applied using a bar coater method so that the dry film thickness of the ink absorption layer was 8μ, and each was dried under the conditions shown in Table 2.
Transparent recording materials of the present invention (Examples 2 to 7) and recording materials for comparison (Comparative Examples 2 to 5) were obtained.

Inkjet recording was performed on each of the obtained recording materials using four color inks in the same manner as in Example 1 to obtain recorded images.

Regarding the thus obtained recorded image, the recording suitability of the recording material and the suitability for optical equipment were evaluated in the same manner as in Example 1. The results obtained are shown in Table 3.

Procedural amendment (spontaneous) January 18, 1980 Commissioner of the Japan Patent Office 1, Indication of this case 1981 Patent application No. 76557
No. 2, Name of the invention recorded material 3, Relationship with the case of the person making the amendment Patent applicant (100) Canon Co., Ltd. 4, Agent address: 1-9-20 Akasaka, Minato-ku, Tokyo.

Claims (1)

[Claims] (1) In a translucent recording material comprising a translucent base material and an ink absorbing layer provided on the base material, the ink absorbing layer has a saponification degree of 70 to 80 mol. A translucent recording material characterized by containing % of partially saponified polyvinyl alcohol.