JPH11240248A - Recording material for ink jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a recording material best suited for a medium such as advertising which requires a comparatively shorter time of durability by composing an ink receiving layer of particles selected from the group of inorganic particles and organic particles and a hydrophobic organic hinder and structurally integrating a base with there particles using the hydrophobic organic binder. SOLUTION: When using inorganic particles and organic particles alone respectively and using both at the same time, the ink receiving properties are deteriorated, if the percentage of a hydrophobic organic binder for forming an ink receiving layer is too high, and consequently, more time than is required normally has to be spent before an ink could be dry during recording, or when the case is worse, ink liquid runs are generated. On the other hand, when the percentage of the hydrophobic organic binder is high, ink absorption is hindered and when the percentage of the hydrophobic organic binder is too low, the adhesive strength of the particles is diminished resulting in the generation of a dust falling phenomenon in which the particles come off the ink receiving layer. Further, in the absorption of the ink is too smooth during recording, to obtain the ink density and the color tone at a desired level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording material, and more particularly to an ink jet recording material having excellent ink receptivity and good water resistance.

[0002]

2. Description of the Related Art Inkjet printers have been widely used for producing not only documents but also advertisements and other exhibits. The ink of the ink jet printer is a water-soluble ink in which a dye and various auxiliaries are mainly dissolved in water, and a recording material receiving the ink is provided with a coating layer of a water-soluble polymer compound on a base material. And those in which various particles are contained in the coating layer.

[0003]

One of the problems of the conventional ink jet recording material is that it has poor water resistance. That is, since the ink-receiving layer is mainly composed of a water-soluble polymer compound, a recorded matter formed with a water-based ink on the character or image, bleeds when contacted with water, and in severe cases, the recording layer itself is eluted. I will. As one of measures against the problem of poor water resistance, a transparent film is attached to a recording surface. Although this method is effective as a method for ensuring water resistance for a long period of time, the operation of attaching a film is complicated. Recently, there has been a demand for a recording material suitable for the field of exhibiting advertisements and the like, which is required to satisfy durability for a relatively short period of about several months at most. The present invention addresses such a need.

[0004]

The recording material for ink jet recording according to the present invention has, on a substrate, particles selected from the group consisting of inorganic particles and organic particles, and an ink receiving layer composed of a hydrophobic organic binder. It is characterized by the following. This ink receiving layer is easily formed by applying a slurry in which particles selected from the group consisting of inorganic particles and organic particles are suspended in an organic solvent solution of a hydrophobic organic binder to a substrate and drying the slurry. can do.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail. As a substrate of a recording material, a plastic film such as polyester, polyethylene, polypropylene, polyvinyl chloride, etc .; Any material known as a base material of a recording material can be used. Usually, a plastic film having good water resistance and good handleability, especially a polyethylene terephthalate film, is preferably used. The thickness of the substrate is usually 1
The thickness is from 0 to 150 μm, particularly from 25 to 120 μm, and may be appropriately selected in consideration of the use and handleability of the recorded matter. The ink receiving layer is composed of particles selected from the group consisting of inorganic particles and organic particles, and a hydrophobic organic binder, and has a structure in which these particles are bound to a substrate with a hydrophobic organic binder. .

As the inorganic particles, calcium carbonate, talc, clay, silica, diatomaceous earth, aluminum silicate, magnesium silicate, calcium silicate, alumina, zeolite, barium sulfate, calcium sulfate and the like are used.
These may be used alone or in combination. Among them, it is preferable to use porous calcium carbonate having excellent ink absorbency. The porous calcium carbonate can be used alone or in combination with other inorganic particles other than calcium carbonate. In such a case, it is preferable that at least 50% by weight of the porous calcium carbonate is porous calcium carbonate. As the porous calcium carbonate, the particle size is usually 1 to
20 [mu] m, preferably 2 to 8 m, BET specific surface area is 3~70m ² / g, preferably 5 to 50 m ² /
g, oil absorption by JIS K-5421 method is 30 to 200
ml / 100 g, preferably 50-170 ml / 100
g.

Particularly preferred as inorganic particles are aragonite calcium carbonate. This is a needle-like crystal, and it is preferable to use a crystal having a needle-like or sea urchin shell-like appearance in which the needle-like crystals are entangled. When aragonite calcium carbonate is used, an ink receiving layer having high surface hardness and high strength can be formed. This is probably because the particles are entangled with each other due to the specificity of the particle structure. The aragonite calcium carbonate generally has a particle size of 1 to 20 μm, preferably ² to 8 μm, and a BET specific surface area of 3 to 70 m ² /
g, preferably 5 to 50 m ² / g, JIS K-542
The oil absorption by the method 1 is 30 to 200 ml / 100 g, preferably 50 to 170 ml / 100 g.

The aragonite calcium carbonate may be used in combination with other inorganic particles as described above, if desired.
Even in that case, it is preferable that at least 50% by weight of the inorganic particles is aragonite calcium carbonate. As the inorganic particles used in combination, the above-mentioned porous calcium carbonate is preferable. For example, aragonite calcium carbonate is 50% by weight.
As described above, the combination of the inorganic particles in which at least a part of the remaining inorganic particles is the above-described porous calcium carbonate is one of the preferable embodiments constituting the ink receiving layer of the recording material of the present invention.

As the organic particles, acrylic resin, urea resin, melamine resin, phenol resin, styrene resin and the like are used. Among them, it is preferable to use a urea resin. The urea resin has a particle size of 0.1 to 50 μm, particularly 1 μm.
5 μm, oil absorption by JIS K-5101 method is 20
0-1500ml / 100g, especially 400-1100m
It is preferable to use 1/100 g. Usually, a urea resin is used alone. Of course, other substances can be used in combination, but even in this case, at least 50% by weight of the organic particles is used.
It is preferable to use a urea resin.

As the hydrophobic organic binder, a solvent soluble in a solvent is usually used. For example, polyvinyl butyral, polyester, acrylic resin, ethylene-vinyl acetate copolymer, polyetherimide, polysulfone,
Polyurethane or the like is used. Among them, it is preferable to use the polyester alone or a mixture of the polyester and another solvent-soluble resin in which the polyester accounts for 50% by weight or more. As such a mixture, for example, a mixture of a polyester and 5 to 30% by weight of a polyacrylate is used. This gives an ink-receiving layer with better ink absorption than the polyester alone. Since water resistance tends to decrease when a polyacrylic acid ester is blended, a water resistance improver such as magnesium stearate is preferably used in an amount of 2 to 30% by weight based on the binder.

[0011] The ink receiving layer essentially comprises particles selected from the group consisting of the above-mentioned inorganic particles and organic particles, and a hydrophobic organic binder. The inorganic particles and the organic particles can be used alone or in combination. When the inorganic particles and the organic particles are used alone, a hydrophobic organic binder 100
It is preferable to use these particles in an amount of 30 to 200 parts by weight, especially 50 to 180 parts by weight, based on parts by weight. When both are used in combination, it is preferable to use inorganic particles and organic particles in a total amount of 30 to 220 parts by weight, particularly 50 to 180 parts by weight, based on 100 parts by weight of the hydrophobic organic binder. The mixing ratio (weight ratio) of the inorganic particles and the organic particles is preferably from 20:80 to 80:20.

In either case where the inorganic particles and the organic particles are used alone or in the case where both are used, if the ratio of the hydrophobic organic binder forming the ink receiving layer is too large, the ink receptivity decreases. ,as a result,
In recording, it takes a long time to dry the ink, and in extreme cases, dripping of the ink occurs. In addition, the formed recorded matter also has low hydrophobicity, and ink bleeds easily when wet with water. This is because the ink should be absorbed and retained in the gap between the particles and the pores in the particle, so that the ratio of the hydrophobic organic binder to the particle becomes too large and the surface of the particle is considerably large. It is considered that when the portion is coated with the hydrophobic organic binder, the absorption of the ink is hindered and the ink is held on the hydrophobic organic binder as it is. On the other hand, if the ratio of the hydrophobic organic binder is too small, the adhesion strength of the particles is weak, and powder dropping of the particles from the ink receiving layer occurs. In addition, the ink absorption may be too good at the time of recording, and a desired density or color tone may not be obtained.

The ink receiving layer is formed by dissolving the above-mentioned hydrophobic organic binder in an organic solvent, adding a slurry selected from the group consisting of inorganic particles and organic particles to the solution, and suspending the slurry. It can be easily formed by coating and drying. Any organic solvent may be used as long as it dissolves the hydrophobic organic binder and does not dissolve these particles, and it is preferable to use a solvent having a relatively low boiling point so as to be easily dried. Generally, general-purpose solvents such as methyl ethyl ketone, isopropyl alcohol, toluene, methyl isobutyl ketone, ethyl acetate, butyl acetate, cyclohexanone, and xylene are used.

In the slurry for forming the ink receiving layer,
If desired, various auxiliaries such as a surfactant, a dispersant, an ultraviolet absorber, a light stabilizer, a thickener, a defoamer, a dye, and a fluorescent brightener may be added. For example, when an appropriate amount of a surfactant is contained in the ink receiving layer, the fixability of the ink during recording is improved. This seems to be due to the fact that the surfactant promotes the movement of the ink. However, if the amount of the surfactant is too large, bleeding occurs due to the diffusion of the ink in the horizontal direction during printing, and the water resistance of the formed printed matter is reduced, so that the bleeding of the ink is easily caused when wet with water. The concentration of the surfactant in the ink receiving layer is 0.1 parts by weight or less, especially 0.0% by weight, per 100 parts by weight of the hydrophobic binder.
It is preferable that the content be 5 parts by weight or less. The surfactant may be added later to the ink receiving layer formed by coating and drying, in addition to being added to the slurry for forming the ink receiving layer. For example, a method of forming an ink receiving layer on a base material and then immersing the ink receiving layer in a surfactant solution or applying a surfactant solution to the ink receiving layer can be used. Examples of the surfactant include an anionic surfactant, a cationic surfactant, an amphoteric surfactant, and a nonionic surfactant. Among them, an anionic surfactant or a cationic surfactant is used alone. Or
Alternatively, it is preferable to use them in combination. In general, the combination of the two gives a better ink receiving layer. As these surfactants, sodium alkylbenzene sulfonate,
Conventional ones such as sodium alkane sulfonate, sulfate of higher alcohol, amine salt having a long chain alkyl group and quaternary ammonium salt can be used.

As a UV absorber or a light stabilizer for improving weather resistance, ordinary hindered amine compounds, benzotriazole compounds, benzophenone compounds, benzoate compounds and the like may be used alone or in combination. In order to apply the slurry onto the substrate, any conventional coating method such as bar coating, blade coating, die coating, reverse roll coating, and gravure roll coating can be used. The coating film thickness, that is, the thickness of the ink receiving layer is preferably from 10 to 100 μm, particularly preferably from 20 to 80 μm. If the ink receiving layer is too thin, the ink absorbency and fixability at the time of recording are poor, causing ink dripping, and the formed printed matter has poor water resistance, and the ink oozes out when wet with water. Get up. In addition, in order to enhance the adhesiveness between the ink receiving layer and the base material, an adhesive layer may be formed on the base material by coating, and the ink receiving layer may be formed thereon.
The ink receiving layer can be provided on both sides of the substrate if desired, but is usually provided only on one side of the substrate. The other surface may be left as it is, but in the case of a substrate for an exhibit such as an advertisement, it is preferable to form an adhesive layer on the other surface.

As the adhesive, a common adhesive such as natural rubber, isoprene rubber, styrene butadiene rubber, ethylene-vinyl acetate copolymer, acrylic resin, polyester resin, polyisobutylene, etc. is used. Dry film thickness of 2 to 50 μm, preferably 5 to 30 μm
m may be applied. Usually, it is preferable to use an acrylic resin or a polyester resin in terms of weather resistance and light resistance. It is preferable to provide a protective layer such as a polyester film coated with a release agent such as a silicone resin on the adhesive layer in terms of the production and handling of the recording material and the operation during recording.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. Formation of an ink receiving layer: As a hydrophobic organic binder solution, a toluene / methyl ethyl ketone mixed solution of a hydrophobic polyester resin (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., Polyester LP-044, resin concentration: 30% by weight) was used. The particles and the surfactant shown in Table-1 were added to 100 parts by weight of the hydrophobic polyester resin in the amounts shown in Table 1, and the mixture was stirred well to obtain a uniform composition. This slurry is
The receiving layer was formed by coating the surface of a biaxially stretched polyethylene terephthalate film having a thickness of 100 μm so as to have a dry thickness of 40 μm. The surface of each of the formed ink receiving layers was smooth.

The symbols in Table 1 represent the following. Particle A: Aragonite calcium carbonate (Shiraishi Industry Co., Ltd., Callite SA, specific surface area 8 to 10 m ² / g, oil absorption 80 to 110 ml / 100 g, average particle size 3.3 μm) Particle B: Porous calcium carbonate (Shiraishi Industry Particle, C: urea formaldehyde resin (Nippon Kasei Co., Ltd. product, Callite KT, average particle size 2.6 μm)
Organic filler, average particle size 3.8 μm) Surfactant A: anionic surfactant (Haogenol L-95, product of Kao Corporation) Surfactant B: cationic surfactant (Lion Co., Arcard C- 50)

Evaluation of ink receiving layer: The ink receiving layer formed above was evaluated for its strength, water resistance, water permeability, bleeding and drying during recording, and peel strength as described below. The results are shown in Table 1.

[Strength of ink receiving layer]
After leaving for 24 hours in an atmosphere of 3 ° C. and 55% humidity,
From this, a sample having a width of 12 mm and a length of 150 mm was cut out. On the ink receiving layer surface of this sample, a width of 12 mm
An adhesive tape having a length of 150 mm (product of Nichiban Co., Cellotape) was overlaid, and a rubber roller having a weight of 2 kg was reciprocated from the adhesive tape side by one reciprocation to be pressed. After leaving this in the same atmosphere as above for 1 hour, the adhesive tape was peeled off, and the state of occurrence of loss or destruction of the ink receiving layer was observed.

[Water resistance of ink receiving layer]
C. in water at first, 6 times every 10 minutes first, then 30 times
Fourteen times every minute, and then every 24 hours, the surface of the ink receiving layer was rubbed five times with the thumb to dissolve the ink receiving layer,
The occurrence of defects was observed.

[Water Permeability of Ink Receiving Layer] After the recording material was left in an atmosphere of a temperature of 23 ° C. and a humidity of 55% for 24 hours, a sample having a width of 15 mm and a length of 150 mm was cut out from this, and one side of the sample was cut out. A marking line was drawn in the width direction at a position of 5 mm. On the other hand, pour water at 23 ° C. to a transparent and flat bottomed container to a depth of 5 mm, and place the recording material into the container so that the marked side is down and the sample is perpendicular to the water surface. The sample was immersed for 1 minute, and the water absorption height at which water rose in the sample for 1 minute was measured.

[Bleeding and Drying of Ink at the Time of Recording] After the recording material was left in an atmosphere of a temperature of 23 ° C. and a humidity of 55% for 24 hours, an ink jet printer (manufactured by Sharp Corporation, IO-735, manufactured by Sharp Corporation) was used in the same atmosphere. ) Using commercially available cyan, yellow and magenta pigment-based aqueous inks (single printing of each ink and overlapping printing of cyan + yellow, cyan + magenta and yellow + magenta), and the ink bleeding state And a dry state were observed.

[Peel strength] The recording material was left in an atmosphere at a temperature of 23 ° C and a humidity of 55% for 24 hours, and a sample having a width of 25 mm and a length of 200 mm was cut out. An adhesive surface of an adhesive tape (manufactured by Lintec Corporation, Neocraft tape) having a width of 25 mm and a length of 200 mm was also overlaid on the sample, and a rubber roller having a weight of 2 kg was reciprocated from the adhesive tape side by one reciprocation to be pressed. Note that, in a range of 50 mm in length from one end of the sample, a release paper was placed so that the adhesive tape did not adhere. After leaving for 1 hour in an atmosphere at a temperature of 23 ° C. and a humidity of 55%, the recording material and the adhesive tape were peeled in a 180 ° direction using a tensile tester at a constant speed of 300 mm / min. It was measured.

[0025]

[Table 1]

[0026]

[Table 2]

The evaluation of water resistance in Examples-1 to 6 was performed for 10 days, during which time the water resistance was all good.
In Example 1, the tendency of the ink to pop when printing with cyan was slightly observed. Comparing Examples-2 to 4, Examples-2 and 3 tend to dry a little slower. Examples -5 and 6 appear to be slightly weaker than the others. The bursting of the ink when printing in cyan is described in Example-
In comparison with Example 1, Example-5 had a slightly weaker tendency to pop, while Example-6 was slightly stronger. In Examples -2 to 4, no popping of the ink is observed. The water resistance in Examples -7 to 12 was evaluated for 15 days, and the water resistance in Examples -7 to 10 was good. In Example-7, there was a slight tendency for the ink to pop when printing was performed in cyan. Comparing Examples -8 to 10, Examples -8 and 9 tend to dry a little slower. Examples-11 and 12 seem to be slightly weaker than the others. The burst of the ink when printed in cyan was smaller than that in Example 7 in comparison with Example-7.
11 has a slightly weaker tendency to pop, while Example-12 is slightly stronger. In Examples -8 to 10, no popping of the ink was observed. Comparing Example-4 with Examples-7 to 12, Example-4 tends to dry a little faster but has a weaker strength.

The evaluation of water resistance in Examples 13 to 16 was 3
The test was performed for 0 days, and Examples 13 and 14 had good water resistance during this period. Judgment after 30 days,
Example-13 clearly has better water resistance than Example-14. The print quality of Examples -13 to 16 is all good, but Example -13 tends to have slightly larger bleeding. This is presumably due to the movement of the ink along the needle crystals of the particles A. In Example-13, drying of the ink tends to be slightly slow. The evaluation of water resistance in Examples 17 to 31 was performed for 10 days, and during this period, the water resistance was all good. In Examples 17 and 21, there was a slight tendency for ink to pop when printing with cyan, but Example 17 had a slightly stronger tendency to pop.
In Examples -18 to 20, ink burst was not observed. Comparing Examples-18 to 20, Example-18,
No. 19 tends to dry a little slower. Example-21 appears to be slightly weaker than Examples-18-18.

In Examples 22 and 27, there was a slight tendency for the ink to pop when printing with cyan. When Examples 23 to 25 and 28 to 30 are compared, Example
23, 24, 28 and 29 tend to dry slightly slower.
Between Examples-22 to 31, Examples-26 and 31 appear to be slightly weaker than others. In the examples 22 to 31, the popping of the ink at the time of printing with cyan was smaller in the examples -26 and 31 than in the examples -22 and 27.
The tendency to pop is slightly weak. Examples -23 to 25 and 2
At 8 to 30, no popping of the ink is observed.

Claims (15)

[Claims] 1. A recording material for ink-jet recording, comprising a substrate and particles selected from the group consisting of inorganic particles and organic particles and an ink receiving layer composed of a hydrophobic organic binder. 2. An ink receiving layer comprising inorganic particles and a hydrophobic organic binder, wherein the ratio of both is 30 to 200 parts by weight of inorganic particles per 100 parts by weight of the hydrophobic organic binder. Recording material for inkjet. 3. An ink receiving layer comprising organic particles and a hydrophobic organic binder on a substrate, wherein the ratio of the organic particles is 30 to 200 parts by weight per 100 parts by weight of the hydrophobic organic binder. Recording material for inkjet. 4. An ink jet recording material comprising an ink receiving layer comprising inorganic particles, organic particles and a hydrophobic organic binder on a substrate. 5. The method according to claim 1, wherein the inorganic particles, the organic particles and the hydrophobic organic binder are formed on a base material, and the ratio of the hydrophobic organic binder to the total of the inorganic particles and the organic particles is 100 parts by weight of the hydrophobic organic binder. And a total of 30 to 220 parts by weight of organic particles and an ink receiving layer in which the weight ratio of inorganic particles to organic particles is 20:80 to 80:20. . 6. At least 50% by weight of the organic particles have a particle size of 0.1 to 50 μm and an oil absorption of 200 to 1500 ml / 1.
The urea resin according to claim 1, wherein
6. The recording material for inkjet according to 3, 4, or 5. 7. At least 50% by weight of the inorganic particles is calcium carbonate having a particle size of 1 to 20 μm, a BET specific surface area of 3 to 70 m ² / g, and an oil absorption of 30 to 200 ml / 100 g. The inkjet recording material according to claim 1, 2, 4, 5, or 6. 8. Aragonite calcium carbonate having a particle size of 1 to 20 μm, a BET specific surface area of 3 to 70 m ² / g and an oil absorption of 30 to 200 ml / 100 g at least 50% by weight of the inorganic particles. Claim 1, characterized in that:
7. The inkjet recording material according to 2, 4, 5 or 6. 9. Aragonite calcium carbonate having a particle size of 1 to 20 μm, a BET specific surface area of 3 to 70 m ² / g and an oil absorption of 30 to 200 ml / 100 g, at least 50 parts by weight of the inorganic particles, At least a part of the inorganic particles has a particle size of 1 to 20 μm and a BET specific surface area of 3 to 70 m ^2.
/ G, a porous calcium carbonate having an oil absorption of 30 to 200 ml / 100 g.
7. The inkjet recording material according to 2, 4, 5 or 6. 10. The inorganic particles, the organic particles and the hydrophobic organic binder on the substrate, and the ratio of the hydrophobic organic binder to the total of the inorganic particles and the organic particles is such that the inorganic particles per 100 parts by weight of the hydrophobic organic binder. And the organic particles are 30 to 220 parts by weight in total, the weight ratio of the inorganic particles to the organic particles is 20:80 to 80:20, and at least 50% by weight of the inorganic particles has a particle size of 1 to 20 μm; BET
Specific surface area is 3 to 70 m ² / g, oil absorption is 30 to 200 m
1/100 g of aragonite calcium carbonate, wherein at least 50% by weight of the organic particles have a particle size of 0.1 to 50%.
A recording material for ink-jet recording, comprising an ink receiving layer which is a urea resin having a thickness of 200 μm and an oil absorption of 200 to 1500 ml / 100 g. 11. Aragonite calcium carbonate having a particle size of 1 to 20 μm, a BET specific surface area of 3 to 70 m ² / g and an oil absorption of 30 to 200 ml / 100 g, at least 50% by weight of the inorganic particles, At least a part of the inorganic particles has a particle diameter of 1 to 20 μm and a BET specific surface area of 3 to 70 m.
² / g, oil absorption is characterized in that calcium carbonate is 30 to 200 ml / 100 g, 10. ink jet recording material as claimed. 12. The ink receiving layer is formed by applying a slurry in which particles forming the receiving layer are suspended in an organic solvent solution of a hydrophobic organic binder to a substrate. An inkjet recording material according to any one of claims 1 to 11. 13. The ink jet recording material according to claim 1, wherein the ink receiving layer contains a surfactant. 14. The ink-jet recording material according to claim 1, further comprising an adhesive layer between the substrate and the ink-receiving layer. 15. At least 50 of a hydrophobic organic binder.
15. The inkjet recording material according to claim 1, wherein the weight% is a polyester resin.