JPS62233285A - Recording medium - Google Patents

Abstract

PURPOSE:To obtain superior ink accepting properties and the clarity of a recording image, by a method wherein an ink accepting layer contains water-soluble monomeric units more than a specific ratio together with a water-insoluble copolymer. CONSTITUTION:A copolymer used in an ink accepting layer is a substantially water-insoluble copolymer containing water-soluble monomeric units 10% or more. The above copolymer can be obtained by performing the copolymerization of a water-soluble monomer and a water-insoluble monomer. A monomer of acrylic series is preferably used; for example, with approximately 30-100wt% of acylic monomer to the total monomer, a film can be superior in strength, water resistance, transparency, light resistance, and the other physical properties as well as enhanced in properties as the ink accepting layer. Undesirably, with less than 10wt% of the water-soluble monomer, the ink accepting layer is adequately superior in water resistance but inferior in ink accepting properties, and with 90wt% or more of the water-soluble monomer, the obtained copolymer is water-soluble and the ink accepting layer is insufficient in water resistance.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is suitable for recording with various writing instruments, recording devices, etc. that use water-based ink, and is particularly suitable for recording materials that are suitably used in inkjet recording systems that use water-based ink. In particular, the present invention relates to a recording material that has excellent ink receptivity, clearness of recorded images, water resistance, etc.

(Prior art) The inkjet recording method uses various ink ejection methods, such as an electrostatic suction method, a method that applies mechanical vibration or displacement to the ink using a piezoelectric element, and a method that applies mechanical vibration or displacement to the ink using a piezoelectric element. Recording is performed by generating and flying small droplets of ink using a method using
This method is attracting attention as a method that generates little noise and can perform high-speed printing and multicolor printing.

Ink for inkjet recording methods is safe,
From the viewpoint of recording characteristics, those containing water as a main component are mainly used, and polyhydric alcohols and the like are often added to prevent nozzle clogging and improve ejection stability.

The recording material used in this inkjet system has conventionally been a recording material such as ordinary paper or a base material called inkjet recording paper on which a porous ink receiving layer is provided. However, as the performance of inkjet recording apparatuses increases and becomes more widespread, such as faster recording speeds and multicolor recording, more advanced and wide-ranging properties are being required of recording materials. In other words, the recording material for inkjet recording to obtain high-resolution, high-quality recorded images must (1) be able to receive ink as quickly as possible on the recording material, and (2) have overlapping ink dots. (3) Ink droplets do not spread on the recording material and the diameter of the ink dots does not become larger than necessary.

(4) The shape of the ink dot is close to a perfect circle and its circumference is smooth. (5) The OD (optical density) of the ink dot is high and the area around the dot is not blurred. (6) High humidity It is necessary to satisfy basic requirements such as excellent water resistance such that the surface does not become sticky even under various conditions and the image does not become distorted even if water droplets adhere to it.

Furthermore, in order to obtain high-resolution recorded image quality comparable to color photography using a multicolor inkjet system, in addition to the above required performance, (7) the coloring components of the ink must have excellent color development; (8) ) Particularly excellent ink fixing properties, as the same number of droplets as the number of ink colors may adhere to the same location in an overlapping manner.

(9) The surface is glossy; (10) High whiteness; etc. are required in a weighted manner.

In addition, images recorded by the inkjet method have traditionally been used exclusively for surface image observation, but as the performance of inkjet recording devices improves and becomes more widespread, there is a demand for recording materials suitable for purposes other than surface image observation. Other uses for recording materials other than the 0 surface image observation that are becoming increasingly popular include slides and 0 surface images.
Optical devices such as HP (overhead projectors) are used to project recorded images onto a screen and observe those images, color separation plates used to create positive plates for color printing, color LCDs, etc. Examples include CMF (color mosaic filter) used in displays.

When a recording material is used for surface image observation, the diffused light of the recorded image is mainly observed, whereas for recording materials used in these applications, the problem is mainly the transmitted light of the recorded image. Become. Therefore, it is required to have excellent light transmittance, especially linear light transmittance, in addition to the above-mentioned performance requirements of the general recording material for inkjet recording.

(The problem that the invention is trying to solve) However,
The reality is that there is still no known recording material that satisfies all of these required performances.

In addition, many conventional recording materials for surface image observation use a method in which a porous ink-receiving layer is provided on the surface, and the ink is received in the porous voids to fix the recording material. The surface of the recording material was not glossy due to the nature of the recording material. On the other hand, when the surface of the ink-receiving layer is non-porous, non-volatile components such as polyhydric alcohols in the ink remain on the surface of the recording material for a long time after recording, and the drying and fixing time of the ink is long. However, there are disadvantages in that clothing may get dirty or the recorded image may be damaged if it comes into contact with the recorded image.

In addition, in the case of a recording material in which a water-soluble polymer is used to form an ink-receiving layer in order to improve affinity with ink and ink receptivity, this ink receptacle is used.

Water-based When recording with ink, there is a problem that the ink receiving layer may partially dissolve or be destroyed.

These problems can be solved by forming an ink-receiving layer using a water-dispersible hydrophobic resin (emulsion or latex) or a hydrophobic polymer solution, but in this case, the ink receptivity to water-based ink decreases. However, practicality is lost.

An object of the present invention is to provide a recording material for inkjet recording that is particularly excellent in ink receptivity and the clarity of recorded images.

Another object of the present invention is to provide an inkjet recording material having a porous ink-receiving layer on the surface, which can form a recorded image particularly excellent in ink receptivity, ink color development, resolution, and water resistance. The goal is to provide recording materials.

Another object of the present invention is to provide a recording material for full-color inkjet recording that has excellent ink receptivity, sharpness of recorded images, water resistance, and surface gloss.

Still another object of the present invention is to use an optical device such as a slide or an OHP to project a recorded image onto a screen for observation, a color separation plate when creating a positive plate for color printing, or a liquid crystal display. An object of the present invention is to provide a recording material for inkjet recording that can be used for transmitted light observation such as CMF used in color displays.

The above and other objects of the invention are achieved by the following invention.

(Disclosure of the Invention) That is, the present invention provides a recording material comprising a base material and an ink-receiving layer provided on the Omura, wherein the ink-receiving layer contains 10% by weight or more of water-soluble monomer units, The recording material is characterized in that it contains a copolymer that is substantially insoluble in water.

To explain the present invention in detail, the recording material of the present invention has a recording surface containing 10% by weight or more of one unit of a water-soluble monomer,
The main feature is that it contains a copolymer that is substantially insoluble in water, and the object of the present invention is mainly achieved thereby.

Conventionally, polyvinyl alcohol, polyvinylpyrrolidone,
Water-soluble polymers such as hydroxyethyl cellulose have been used to form ink-receiving layers of recording materials for inkjet systems, but the following problems have arisen with these conventional recording materials.

(1) When the humidity of the surrounding atmosphere decreases, the water content of the ink-receiving layer decreases, and the ink-receptivity of the ink-receiving layer decreases significantly. This tendency is particularly remarkable in the case of polyvinyl alcohol.

(2) On the other hand, when the surrounding atmosphere is under high humidity conditions, the ink-receiving layer absorbs moisture and the surface becomes sticky, causing problems such as disturbance of one image, blocking, or destruction of the ink-receiving layer. This tendency is particularly remarkable in the case of polyvinylpyrrolidone.

(3) The same problem as above occurs when recording materials are stored for a long period of time.

A method of cross-linking water-soluble polymers has been considered as a method to solve these problems, but in this case, the ink receptivity of the ink-receiving layer is significantly reduced, and non-hydrophilic polymers Similarly, when using the ink receptivity, the ink receptivity was significantly lowered, making it unsuitable for use.

As a result of intensive research to solve the various problems related to the use of water-soluble polymers as described above, the present inventors have discovered that the various problems described above can be solved by using the specific copolymer described above for forming an ink-receiving layer. It was discovered that the problems could be solved at the same time.

The recording material of the present invention generally consists of a base material as a support and an ink-receiving layer provided on the surface thereof. (2) the surface of the ink-receiving layer is smooth; and (3) the ink-receiving layer is porous. It will be done.

Further, each ink receiving layer may also function as a support at the same time.

To explain the present invention in more detail using some of the above preferred embodiments as representative examples, the copolymer that mainly characterizes the present invention is a substantially water-insoluble copolymer containing 10% or more of one unit of a water-soluble monomer. Such a copolymer can be obtained by copolymerizing a water-soluble monomer and a water-insoluble monomer according to a conventional method, and can also be easily obtained and used from the market.

Examples of water-soluble heptamers used in forming the above copolymers include acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic acid half ester, fumaric acid, styrene sulfonic acid, vinyl sulfonic acid, etc. Ionic salts or their alkali metal salts, ammonium salts, amines, etc.: N-hinyl-2-pyrrolidone, 4-vinylpyridine, N-trialkylaminomethylstyrene, 4-vinylimidazole, dialkyl diallylammonium salts , vinylbenzylaminosulfonium salt, vinylbenzylaminophosphonium salt, N,N-dimethylaminopropyl (meth)acrylate, N,N-
Cationic monomers such as dimethyl (meth)acrylamide, N,N-dimethylaminoethyl (meth)acrylate, N,N-diethylaminoethyl (meth)acrylate, or salts thereof: (meth)acrylamide, N
-Methylol (meth)acrylamide, allyl alcohol, 2-hydroxyethyl (meth)acrylate, 2-
Examples include nonionic monomers such as hydroxypropyl (meth)acrylate and polyethylene glycol mono(meth)acrylate.

Examples of hydrophobic monomers copolymerized with the water-soluble monomers mentioned above include methyl (meth)acrylate, butyl (meth)acrylate, ethylhexyl (meth)acrylate, glycidyl (meth)acrylate, dodecyl (meth)acrylate, The water-soluble monomers such as (meth)acrylic acid esters, vinyl acetate, vinyl chloride, vinylidene chloride, styrene, dicyclopentadiene, ethylene, propylene, etc. and hydrophobic monomers are merely examples. However, any other known hexamers can be used in the present invention.

Among these wood-philic monomers and hydrophobic monomers, it is particularly preferable to use acrylic monomers.
For example, when about 30 to 100% by weight of all the seven materials is acrylic seven materials, it is possible to obtain a film that has excellent strength, water resistance, transparency, light resistance, and other physical properties of the film, and is also good as an ink-receiving layer. can be formed.

In the present invention, a copolymer consisting of the above-mentioned heptamers is used, but it is necessary that these copolymers contain 10% by weight or more of one unit of a water-soluble monomer,
Furthermore, the amount used must be such that the copolymer as a whole does not become water-soluble. As long as these conditions are met, any 7-mer ratio may be used, but generally the water-soluble 7-mer ratio is 10 to 10.
The content of the water-soluble monomer is preferably less than 10% by weight, an ink-receiving layer with sufficiently excellent water resistance is formed, but the ink-receptivity of the ink-receiving layer becomes low; If more than 90% by weight of the water-soluble monomer is used, the copolymer becomes water-soluble and the water resistance of the formed ink-receiving layer becomes insufficient, so it is not preferable.
When the copolymer is insoluble in water even though it contains more than 90% by weight of water-soluble monomers, the water-soluble monomer can be 90% by weight or more.

Further, the molecular weight of the above copolymer is 5.000-1
The molecular weight is preferably about 1,000,000,000,000, and if the molecular weight is less than 5,000, problems such as low film strength of the formed ink-receiving layer and tackiness occur. Particularly, the areas that have received the ink become sticky. On the other hand, if the molecular weight exceeds 1 million, the viscosity of the polymer solution becomes too high, which is undesirable, such as causing problems in the operation of forming the ink-receiving layer and lowering the leveling properties of the formed ink-receiving layer.

By forming the ink-receiving layer of a recording material using the specific copolymer described above, a recording material that has excellent ink receptivity and provides high-quality recorded images such as water resistance can be obtained. .

As the base material used as the support for the ink-receiving layer in the present invention, any conventionally known base material such as transparent or opaque base material can be used. Examples suitable for the transparent base material include, for example, polyester resin, Diacetate resin, triacetate resin, acrylic resin, polycarbonate resin,
Polyvinyl chloride resin, polyimide resin, cellophane,
Examples include films or plates such as celluloid and glass plates. In addition, examples of preferred opaque substrates include general paper, cloth, wood, metal plates, synthetic paper, etc., as well as the above-mentioned transparent substrates treated to make them opaque by known means. .

Although the thickness of these base materials is not particularly limited, it is generally about 1 to 5,00071 m.

The recording material of the present invention is formed using the above-mentioned main materials, but in the preferred embodiment (1) above, both the base material and the ink receiving layer are translucent, and the recording material as a whole is transparent. This is a photosensitive embodiment. This type of recording material has particularly excellent light transmittance, and is mainly used in OHP applications in which a recorded image is projected onto a screen or the like using an optical device, and is useful as a recording material for transmitted light observation. .

Such a translucent recording material can be produced by forming a translucent ink-receiving layer on the translucent base layer from the above-mentioned copolymer alone or a mixture of the copolymer and another translucent polymer. It can be prepared.

As a method for forming such an ink-receiving layer, a coating solution is prepared by dissolving or dispersing the above-mentioned copolymer alone or a mixture thereof with other polymers in an appropriate solvent, and the coating solution is mixed with, for example, It is preferable to apply the transparent substrate on the Murakami surface by a known method such as roll coach ink method, rod bar coating method, spray coating method, air knife coating method, etc., and then quickly dry it.
A method of hot-melt coating the above-mentioned copolymer alone or a mixture with other polymers, or another method such as forming a single sheet for an ink-receiving layer from the above-mentioned materials and then laminating the sheet to the above-mentioned substrate. But that's fine.

In the present invention as described above, the thickness of the ink receiving layer formed on the base material is usually about 1 to 200 pm, preferably about 5 to 1100 IL.

Preferred examples of other polymers that can be used in combination with the copolymer in the above method include albumin,
Gelatin, casein, starch, cationic starch, gum arabic, natural resins such as sodium alginate, polyamide, polyacrylamide, polyvinylpyrrolidone, quaternized polyvinylpyrrolidone, polyethyleneimine, polyvinylpyricillium halide, melamine resin, polyurethane, carboxymethyl Sejlerose, polyvinyl alcohol, polyester, sodium polyacrylate, SBR latex, NOR latex, polyvinyl formal,
Polymethyl methacrylate, polyvinyl butyral, polyacrylonitrile.

Synthetic resins such as polyvinyl chloride, polyvinyl acetate, phenol resin, and alkyd resin are mentioned, and one or more of these materials may be used as desired.

When such a translucent polymer is used in combination with the copolymer, the weight ratio of the copolymer to the other polymer is 20:l-1:20, preferably 15:1-1:t.
Use within the range o.

In addition, in order to further improve the ink receptivity of the ink receptive layer in the above method, silica, clay, talc, diatomaceous earth, calcium carbonate, fEMt calcium, etc. Fillers such as , barium sulfate, aluminum silicate, synthetic zeolite, alumina, zinc oxide, lithopone, and satin white can also be dispersed in the ink-receiving layer.

The recording material of the embodiment (1) formed as described above is a light-transmitting recording material having sufficient light-transmitting properties.

In the present invention, sufficient light transmittance means that the recording material exhibits a linear light transmittance of at least 2% or more, and preferably a linear light transmittance of 105 or more.

If the linear light transmittance is 2% or more, it is possible to project the recorded image onto a screen and observe it using an OHP, for example.In order to clearly observe the details of the recorded image, it is necessary to It is desirable that the light index is 105 or more.

The linear transmittance T (%) here refers to the amount of light incident perpendicularly to the sample, transmitted through the sample, and at least 8
The spectral transmittance of the straight light that passes through the light-receiving side slit on the extension line of the incident optical path separated by more than cm and is received by the detector is measured using, for example, the 323-type Hitachi self-recording spectrophotometer (manufactured by Hitachi, Ltd.). The Y value of the tristimulus value of the color is determined from the measured spectral transmittance, and is determined by the following equation.

T=Y/Y, rate (install an integrating sphere behind the sample to determine the transmittance including diffused light), opacity (
The white and black backings are placed on the back of the sample and the ratio is calculated. ), which evaluates translucency using diffused light.

The problem with devices that use optical technology is the behavior of straight-line light, so when evaluating the light transmittance of the recording material to be used in those devices, it is important to check the straight-line transmittance of the recording material. It is particularly important to seek

For example, when observing a projected image on an OHP, in order to obtain a clear and easy-to-see image with high contrast between recorded and non-recorded areas, it is necessary that the non-recorded areas of the projected image be bright, that is, the straight line transparency of the recording material. It is required that the light rate be at a certain level or higher. In OHP tests using test charts, in order to obtain images suitable for the above purpose,
The in-line transmittance of the recording material is required to be 2% or more, and preferably 10% or more in order to obtain a clearer image. Therefore, recording materials suitable for this purpose are:
It is necessary that its in-line transmittance is 2% or more.

The preferred embodiment (2) above is also one of the embodiments (1) above, and is characterized in that the surface of the ink-receiving layer is smooth. This type of recording material has particularly excellent surface gloss, and is particularly useful as a recording material for observing surface images in full color and excellent clarity. The recording material in this embodiment may be transparent or opaque, and either the above-mentioned transparent or opaque base materials can be used. The ink-receiving layer formed on these base materials may also be transparent or opaque.The materials and methods used to form the ink-receiving layer are the same as in the embodiment (1) above, but the filler described above may be used. etc. may be used to the extent that the ink-receiving layer becomes opaque, as long as the surface of the ink-receiving layer can maintain smoothness.

If necessary, a cast coating method may be used in addition to the above-mentioned coating method, or glossing may be performed using a gloss roll.

The preferred embodiment (3) above is characterized in that the ink-receiving layer of the recording material of the present invention is a porous ink-receiving layer, and the ink-receiving layer of the recording material has particularly high ink-receptivity. It is also useful for observing surface images with excellent water resistance and full-color clarity.

In addition, the ink-receiving layer also has the function of a support, such as a sizeless paper impregnated with a copolymer using a size press or the like, or a layer according to the above (1) or (2), which retains ink. There are some that have a thicker layer and have the material peeled off. The material and method for forming the ink-receiving layer in this embodiment are substantially the same as those in embodiments (1) and (2) above, but in this embodiment, when forming the ink-receiving layer, the ink-receiving layer is It is characterized by the fact that it contains fillers that allow it to quickly accept ink. Preferred examples of such fillers include, for example, organic filler particles such as polystyrene, polyethylene, urea-formalin resin, polyvinyl chloride, and polymethyl methacrylate, in addition to the fillers described in the above-mentioned embodiment (1). and one or more of these are used. Such a filler that improves ink receptivity is preferably used in the ink-receiving layer in a proportion that accounts for about 10 to 90% of the weight of the ink-receiving layer. If the amount used is below this range, the ink receptivity will not be improved much, and if the amount used is more than this, the physical and mechanical strength of the ink receiving layer will not be sufficient. When using relatively large amounts of such fillers,
Since sufficient film-forming properties may not be obtained with the copolymer alone, it may be desirable to use a polymer other than the above-mentioned copolymer in combination as the binding resin. In such cases, the copolymer is used in the ink-receiving layer in an amount of 1 to 90% by weight, preferably 2 to 50% by weight.

The present invention has been explained above by exemplifying the typical embodiments of the recording material of the present invention, but of course the recording material of the present invention is not limited to these embodiments. Also, the ink-receiving layer contains 1 dispersant, fluorescent dye, pH
Various known additives such as regulators, defoamers, lubricants, preservatives, surfactants, etc. can be included.

Note that the recording material of the present invention does not necessarily have to be colorless, and may be a colored recording material.

According to the recording material of the present invention containing the specific copolymer as described above in the ink-receiving layer, it always exhibits excellent ink absorbency even when the ambient conditions, such as temperature and humidity, change drastically. Since the ink-receiving layer does not become sticky even under humid conditions, various drawbacks of the prior art are satisfactorily solved.

Therefore, under various conditions, even if ink is repeatedly deposited on the same spot within a short period of time during recording, there will be no ink flow or seepage phenomenon, resulting in high-resolution, clear, water-resistant, and excellent color development. A certain image is obtained. Moreover, it is possible to provide excellent surface gloss that cannot be seen with conventional inkjet recording materials, and it is also possible to observe recorded images by projecting them onto a screen, etc. using optical equipment such as slides and OHPs. It can be applied to applications other than conventional surface image observation, such as a color separation plate for creating a positive plate for color printing, or a CMF used for a color display such as a liquid crystal.

Hereinafter, the present invention will be explained in more detail with reference to Examples, Comparative Examples, and Usage Examples. In addition, unless otherwise specified, "1 part" in the text is based on weight.

Reference Example 1 (Synthesis of copolymer) Into 30 flasks, 300 parts of N,N-dimethylaminoethyl methacrylate, 400 parts of allyl alcohol, 300 parts of methyl methacrylate, and 50 parts of isopropyl alcohol were added.
0 parts and 500 parts of methyl ethyl ketone were added and stirred to homogenize.

Next, nitrogen gas was introduced and bubbled for 1 hour, and then 1 part of azobisisobutyronitrile was added.

Raise the temperature to 60°C. 60 hours for 20 hours while passing nitrogen gas
Polymerization was carried out by stirring while maintaining the temperature at °C. The obtained copolymer solution was viscous, and the weight average molecular weight of the produced copolymer was 120,000.

Example 1 90 parts of the copolymer obtained in Reference Example 1 and 10 parts of polymethyl methacrylate (weight average molecular weight 80,000, manufactured by Fuikasei) were dissolved in 400 parts of methyl ethyl ketone. This polymer solution was applied to high-quality paper and dried at 80° C. for 30 minutes to form a coating film having a thickness of 10 μm to obtain a recording material of the present invention.

Reference Example 2 (Synthesis of copolymer) 300 N-methylol acrylamide was added to 30 flasks.
parts, N, N-diethylaminoethyl methacrylate 30
0 parts, butyl methacrylate 100 parts, methyl methacrylate 300 parts, isopropyl alcohol 500 parts and methyl ethyl ketone 500 parts were added and stirred to homogenize.

Next, nitrogen gas is introduced and bubbled for 1 hour, and then 1 part of azobisisobutyronitrile is added and the temperature is raised to 60°C.

Polymerization was carried out by stirring and maintaining the temperature at 60° C. for 20 hours while passing nitrogen gas. The obtained copolymer solution was viscous, and the weight average molecular weight of the produced copolymer was 100,000.

Example 2 90 parts of the copolymer obtained in Reference Example 2 and butyral resin (manufactured by A-Mizu Kagaku Co., Ltd., trade name Kosurek B BM-9)
0 parts of I was dissolved in 400 parts of methyl ethyl ketone. Thereafter, a recording material of the present invention was obtained in the same manner as in Example 1.

Reference Example 3 (Synthesis of copolymer) 700 parts of vinylpyrrolidone, 300 parts of methyl methacrylate, and 1.0 parts of methyl ethyl ketone were placed in 30 flasks.
00 parts and stirred to homogenize.

Next, nitrogen gas is introduced and bubbled for 1 hour, and then 1 part of azobisisobutyronitrile is added and the temperature is raised to 60°C.

Polymerization was carried out by stirring and maintaining the temperature at 60° C. for 20 hours while passing nitrogen gas. The resulting polymer solution is viscous;
The weight average molecular weight of the produced copolymer was 90,000.

Example 3 A recording medium of the present invention was prepared in the same manner as in Example 1 except that 80 parts of the copolymer obtained in Reference Example 3 and 20 parts of hydroxyethylcellulonis were dissolved in 200 parts of isopropyl alcohol and 200 parts of dimethylformamide. I got the material.

Reference Example 4 (Synthesis of copolymer) 7200 parts of N-vinyl-2-pyrrolid and 200 parts of N,N-diethylaminoethyl methacrylate were placed in 30 flasks.
1, 400 parts of 2-hydroxyethyl methacrylate, 200 parts of styrene, 500 parts of inpropyl alcohol, and 500 parts of dimethylformamide, and the mixture was stirred and homogenized.

Next, nitrogen gas was introduced and bubbled for 1 hour, then 1 part of azobisisobutyronitrile was added and the temperature was raised to 60"C. While passing nitrogen gas, the temperature was maintained at 20:00 [160°C and stirred to carry out polymerization. The obtained polymer solution was viscous, and the weight average molecular weight of the produced copolymer was 80,000.

Example 4 A recording material of the present invention was obtained in the same manner as in Example 1 except that 100 parts of the copolymer obtained in Reference Example 4 was dissolved in 200 parts of isopropyl alcohol and 200 parts of dimethylformamide.

Comparative Example 1 100 parts of polyvinyl alcohol (manufactured by Kuraray, trade name: Kuraray Boval PVA-117) was dissolved in 400 parts of water. Thereafter, a recording material of a comparative example was obtained in the same manner as in Example 1.

Comparative Example 2 1,100 parts of Hydroxyethylce Cello was dissolved in 400 parts of water. Thereafter, a recording material of a comparative example was obtained in the same manner as in Example 1.

Reference Example 5 (Synthesis of copolymer) 750 parts of vinyl pyrrolid, 950 parts of methyl methacrylate and 1.00 parts of methyl ethyl ketone were placed in 30 flasks.
0 part was added and stirred to homogenize.

Next, nitrogen gas was introduced and bubbled for 1 hour, and then 1 part of azobisisobutyronitrile was added.

Raise the temperature to 60°C. 60 hours for 20 hours while passing nitrogen gas
Polymerization was carried out by stirring while maintaining the temperature at °C. The obtained copolymer solution was viscous, and the weight average molecular weight of the produced copolymer was 130,000.

Comparative Example 3 A recording material of a comparative example was obtained using the copolymer obtained in Reference Example 4 and in the same manner as in Example 1 except for the following.

Usage example: On-demand inkjet recording head (discharge orifice diameter 60 pm, piezo vibration Inkjet recording was performed using a recording device with a slave drive voltage of 70 V and a frequency of 2 KHz.

Yellow ink (composition) c, r, direct yellow 86 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
70 parts Red ink (composition) C, X, Acid Red 35 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 fi water
7 parts Blue ink (composition) C, R, Direct Blue 86 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
7 parts black ink (composition) c, r, food black 2 2 parts diethylene glycol 20 parts polyethylene glycol #200 10 parts water
70 copies The evaluation results of the above usage example are shown in Part 1 below.
Shown in the table.

In Table 1, each evaluation item was measured according to the following method.

(1) Ink fixation time was measured by leaving the recorded matter at room temperature after recording, and measuring the time required for the ink to dry and stop adhering to the finger when touching the recorded image with the finger.

(2) Water resistance was evaluated by observing whether swelling, peeling, blistering, etc. occurred in the ink receiving layer when the recording material was immersed in still water (18° C.) for 1 minute. o: No occurrence, ×
Occurred (blank space below) 2 shi l - Tech Z Kuja J Hoshikan Within 1 minute Beni - Water 11 Hill 0 0 Techfu 9 Fixed 1 Yoshi! Within 1 minute Within 1 minute 1-1 water 115 〇
〇-stop match-1- 1ヱdan

Claims (3)

[Claims] (1) In a recording material consisting of a base material and an ink-receiving layer provided on the base material, the ink-receiving layer contains 10% by weight or more of water-soluble monomer units and is substantially insoluble in water. A recording material characterized by containing a certain copolymer. (2) The recording material according to claim (1), wherein the copolymer is mainly composed of an acrylic monomer. (3) The recording material according to claim (1), which is used for an inkjet recording method.