JPH07266686A - Ink-jet recording material with good transparency and gloss - Google Patents

Abstract

PURPOSE:To obtain a recording material which gives a high quality image with reduced nonuniformity in a solid printing part and has good gloss, transparency, and water resistance as an ink-jet recording material. CONSTITUTION:An ink absorption layer containing a water soluble polymer having quanternary ammonium base is placed on a support, and silica fine particles and a polymer having p-vinyl phenol units as a component in an amount of 10-150wt.% to the silica are settled on the surface of the absorption layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium for water-based ink using an ink jet recording system, and more particularly to a recording material for ink jet recording having paper, resin-coated paper, film or the like as a support. Is.

[0002]

2. Description of the Related Art In recent years, with the increase in speed of ink jet recording apparatuses, the higher definition of recorded images, and the realization of full color, the quality requirements for recording materials have become more and more strict.
Furthermore, among various ink jet printers that have been developed for full-color recording, models that have the capability of outputting high-definition images that are comparable in image quality to color images produced by conventional silver halide photography have been developed. It is desired to develop a recording material having a high gloss equivalent to that of a silver salt color paper. Alternatively, there is an urgent need for a recording material having high transparency and good image quality as an OHP film.

The basic required performance of the recording material for ink jet is that the density of ink dots is high, the color tone is bright and vivid, and the ink absorption capacity is large and the absorption speed is high, so that the ink dots overlap. Also in this case, it is necessary that ink does not flow out or bleed, and that the shape of ink dots is smooth and the periphery is not blurred. Especially in the case of color recording, usually four colors of ink are used and each color ink is ejected as an ink dot on the recording material in an extremely short time, resulting in insufficient absorption capacity and absorption speed of the recording material for the ink. In such a case, the ink overflows on the surface of the recording material, and a phenomenon occurs in which an image is formed in a form in which the inks are mixed nonuniformly, which becomes a problem.

As conventional recording materials for ink jet, for example, JP-A Nos. 55-51583, 56-157, 57-107879, 57-107880 and 5 are available.
9-230787, 62-160277, 62
184879, 62-183382, 64-
A recording material obtained by coating a paper-containing surface with a silicon-containing pigment such as silica found in JP 11877 together with an aqueous binder has been proposed. The fine pigment particles such as silica used in these examples are oil-absorbing materials. Recording materials with large amounts generally reach a certain level in terms of ink absorption capacity and absorption speed, but it is necessary to introduce a large amount of inorganic pigment such as silica into the coating layer. Therefore, there are drawbacks that the surface gloss of the recording material itself is lowered and the vividness of the color tone required in the case of color recording is lost. Further, such a coating layer itself has low translucency, and when a similar coating layer is provided on a transparent film, there is a problem that the recording material becomes opaque so that it cannot be used for OHP. When colloidal silica is used instead of silica for the purpose of improving gloss and transparency, the method described in JP-A-56-1 is used.
As described in the text of Japanese Laid-Open Patent Publication No. 57-57, it is not preferable because it deteriorates the ink absorption. Alternatively, JP-A-3-
215082, 4-67986, 5-3203
No. 7, etc., there is described a method of forming a recording material having transparency by coating a fine alumina sol with a water-soluble binder on the surface of a support, but the alumina sol in the coating layer is described. If the ratio of (pseudo-boehmite) to the binder is not increased, there is a problem of poor ink absorption. A coating layer with such a high pigment ratio is very prone to cracking of the coating during coating and drying, and the coating amount is also high. If it is not about 20 g / m ² , the ink absorption capacity is not sufficient, so that thick film coating is required, and thus there is a problem that it becomes more difficult to control the drying conditions in actual production. In addition, the coating film strength is weak and there are problems that images are easily peeled off by rubbing the surface where ink jet recording is performed, and various problems that curling easily occurs after printing and transparency is still insufficient. Is.

In order to form a translucent ink absorbing layer which is highly transparent and can be used as an OHP sheet, the above-mentioned various inorganic pigments are not used or the amount thereof is limited to a small amount even if they are used. As a result, the ink absorbency must rely exclusively on the binder used. Examples of binders conventionally used for such applications include, for example, polyvinylpyrrolidone, vinylpyrrolidone-vinyl acetate copolymer, and Japanese Patent Laid-Open No. 60-58185, which are described in JP-A Nos. 57-38185 and 62-184879. 168651
Nos. 60-171143 and 61-134290, and binders mainly composed of polyvinyl alcohol as described in JP-A No. 62-220383, and acrylic polymers having a carboxyl group described in JP-A No. 62-220383. Vinyl acetal polymers disclosed in JP-A-4-214382, JP-A-4-282282,
Various ink-absorbing polymers such as a crosslinkable acrylic polymer as described in JP-A-4-285650 have been proposed, but any of these can achieve both ink absorbability and water resistance of the coating film itself. It is difficult, and there is a problem that the recorded image is easily washed off when washed with water.
Furthermore, in color image recording, the ink absorption capacity and absorption speed are still insufficient, and non-uniform mixing of each color ink occurs on the surface of the recording medium, resulting in remarkable density unevenness particularly when a solid image is recorded. There was a problem to do.

When it is difficult to impart the ink absorption speed and the ink absorption capacity to a single recording layer, the two functions of the two layers are separated as the ink permeable layer and the ink receiving layer, respectively, with the functions of the both being separated. For example, Japanese Patent Laid-Open No. 62-14
No. 0878, No. 62-152779, No. 62-222.
No. 885, No. 62-222886, No. 64-5527.
No. 6, No. 64-55277, No. 2-55185, etc., the addition of an inorganic pigment or the like is limited in any layer in order to ensure translucency and surface gloss. Therefore, even in such a case, the ink absorbency of the binder itself becomes a problem.

[0007]

In any of the above examples, when a large number of ink dots are printed on the surface of a recording material at high speed, as in the case of high speed color recording, the ink absorption speed is high. No recording material was found that satisfied both of the ink absorption capacity and the ink absorption capacity and had excellent surface gloss and translucency. The problem to be solved by the present invention is to provide a recording material having high gloss and excellent transparency, and further to maintain the water resistance of a recorded image in multicolor color recording and to improve the print quality. The purpose is to improve, especially to reduce the density unevenness in the solid printed portion.

[0008]

The above object can be achieved by the present invention described below. That is, paper, resin-coated paper (paper whose surface is coated with polyethylene such as photographic base paper),
An ink absorption layer containing a water-soluble polymer having a quaternary ammonium salt group is provided on a support such as a film, and silica fine particles and p-vinylphenol unit are contained on the upper surface of the ink absorption layer as at least one constituent component. By allowing the polymer to exist in a proportion of 10% or more and 150% or less by weight with respect to the silica fine particles, it was possible to obtain a target recording material having excellent print quality.

The above-mentioned water-soluble polymer having a quaternary ammonium salt group is basically highly water-soluble and has the ability to quickly absorb the ink and retain it inside, but as an ink dye, it is usually an acid dye or a direct dye. As described above, since a dye having a sulfonic acid group in the molecule is used, a bond is formed between the dye and the quaternary ammonium salt in the form of ammonium sulfonate, and the dye is bonded to the water-soluble polymer to be insolubilized. It is a feature. For this reason, the printed image has good water resistance, but conventionally, such quaternary salt type polymers have not been used alone as dye fixing agents, but as additives together with other polymers and pigments. In the present invention, such a polymer having a dye fixing action may be used in the form of being used in combination with another polymer as in the conventional case.
Rather, it has been found that the use of a polymer having a quaternary ammonium salt group as a dye fixing agent as a main binder for absorbing ink further enhances the dye fixing action, which is very preferable. That is, when ink droplets land on such a polymer surface, the dye in the ink reacts with the quaternary ammonium base almost instantaneously and is fixed on the polymer. Even when the image is printed on the recording medium, the dyes of the respective colors are quickly fixed, so that there is an advantage that the resolution of the recorded image is high.

Such fixing action has been well known in the past, but since a water-soluble polymer having a quaternary ammonium salt group absorbs moisture in the air and becomes sticky, another polymer or an inorganic pigment such as silica is used in combination. It was necessary to prevent stickiness or blocking. Under the present circumstances, the problems that the original ink fixing action is weakened and the gloss and transparency of the film are impaired have not been solved. In order to prevent blocking, it has been actively practiced to introduce inorganic pigments such as silica and organic polymer fine particles directly into such an ink absorption layer to give appropriate irregularities to the surface for improvement, but surface gloss and transparency In order to introduce such a so-called matting agent to the extent that does not impair the above, the introduction amount must be kept at a low level, and in such a case, the surface of the matting agent itself is usually covered with the binder polymer. When a polymer having a high hygroscopic property such as a quaternary salt type was used as the main binder, it was extremely difficult to prevent blocking by such a method.

In the present invention, when such a quaternary salt type polymer which is extremely likely to cause blocking is used as a binder component for ink absorption, silica fine particles as a matting agent are directly introduced into a layer containing this polymer. However, it was found that by blocking silica particles on the upper surface of this layer separately from this layer, blocking can be prevented very effectively.

As a further important effect, by introducing silica fine particles to the surface by such a method, the wettability of the surface of the ink absorbing layer with ink is dramatically improved, and a plurality of ink dots land adjacently on the surface. Even in this case, the ink droplets are evenly bonded to each other, and a preferable effect of providing a uniform image density without density distribution is exhibited. That is, when the wettability with respect to the ink on the surface on which the ink lands is poor, the ink dots do not spread appropriately and a part independent of the part where the ink dots are joined to each other is formed, resulting in uneven density and stickiness. The problem arises. Therefore,
By reducing the contact angle of the surface to the ink, and especially when ink dots are ejected adjacent to each other on the surface, it is possible to show high color density without density distribution by actively causing the ink dots to fuse. preferable.

Such silica fine particles are randomly present on the surface of the recording material, and when the size of the silica fine particles is 1 micron or more, good blocking prevention can be achieved only when the silica fine particles are present in a proportion of 1% or more of the total surface area. When it occupies 5% or more, the contact angle with respect to the ink is reduced to eliminate the image density distribution and give a uniform solid image. At this time, the respective silica fine particles are most effective in that they are separated from each other without being aggregated, or that island-like portions of silica particles of 100 microns or less are randomly distributed on the surface. When the silica fine particles are densely gathered in a state of about 100 μm or more, it is not preferable because the surface gloss is not significantly reduced and the effect of decreasing the contact angle to the ink is not exhibited on the surface where the silica fine particles are not present. Further, when the silica fine particles occupy 50% or more of the total surface area of the surface of the recording material, there is a problem that surface gloss is significantly reduced and transparency is also significantly reduced although the contact angle is reduced to improve stickiness. Therefore, in order to obtain a recording material having high gloss and high transparency, which is the object of the present invention, such silica fine particles are preferably 5% or more and 50% or less of the total surface area, and further 5%.
The surface coverage of 25% or less is a very preferable range for preventing stickiness and ensuring high gloss and high transparency. Furthermore, when the surface coverage is 18% or less, the decrease in gloss due to the presence of silica fine particles on the surface can be maintained to such an extent that the gloss can hardly be visually observed, which is extremely preferable. Incidentally, the coverage of silica on the surface is easily calculated from the formula of 1.5 × (coating amount) / (particle radius) from the numerical values of the average particle size and the coating amount. For example, the average particle diameter is 3 μm. Silica particles of 0.3
When the surface is covered with a coating amount of g / m ² , the coverage is about 10
%.

The present invention provides a recording material having a form in which fine silica particles are dispersed on the surface, but the purpose of using fine silica particles is generally that dispersion is very easy and dispersion stability is good. The merit is that even when a liquid containing such fine particles is applied and dried, the particles are applied to the surface in an independent form and are unlikely to form an aggregated form. If the silica fine particles are aggregated and, in a remarkable case, a fine particle layer is formed on the surface, the ink absorbability in this part is high, but the ink penetrates into the gaps between the silica fine particles due to the capillary phenomenon, and the dots spread too much. It is not preferable because the resolution is lowered or the dot shape becomes non-uniform and the image quality is deteriorated.
Therefore, it is extremely important that the silica fine particles do not form a continuous layer, and even if several 100 particles or less are gathered together, the size of this portion should be 100 μm or less. The silica fine particles are discretely or sea-island-distributed on the surface because it is necessary or otherwise causes the problem of unevenness in the image.
It is extremely important that the surface of the lower ink absorbing layer is exposed to at least 50% of the entire surface.

The silica fine particles used in the present invention can be dispersed alone on the surface of the recording material to achieve the purpose of preventing blocking and improving stickiness, but the adhesion with the surface is weak, so that the surface is rubbed. Therefore, the silica fine particles are easily removed, so that permanent blocking is not prevented and the stickiness is not improved. Further, when the surface is touched with a finger, a feeling of discomfort such as powderyness is felt, which is not preferable. Therefore, it is preferable to add a polymer as an adhesive agent for the silica fine particles together with the silica fine particles. However, in general, the addition of the binder polymer causes a drawback that the effect of improving the stickiness due to the silica fine particles is deteriorated. Then, various binder polymers for silica fine particles were investigated, and a polymer containing at least one p-vinylphenol unit as a constituent component provides a recording material excellent in print quality without specifically aggravating stickiness. I found a thing.

Here, p is used as a binder for the silica fine particles.
-It is not clear why the polymer containing vinylphenol units is particularly effective, but it is estimated as follows.
In general, water-based inks used for ink jet recording often contain solvents such as high-boiling alcohols such as glycerin and ethylene glycol, and various alcohols for the purpose of preventing nozzle clogging. Must have an affinity for these alcohol components as well as the water in the aqueous ink. Water, which occupies most of the water-based ink, is mainly absorbed by the ink absorption layer, but at the same time, it is also required to effectively absorb the alcohol component, but it is necessary to select a material that efficiently absorbs both of them. Very limited. Therefore, it is desirable that the binder that adheres the silica fine particles to some extent absorb the alcohol in the ink immediately after the ink droplets land. P contained in the binder polymer in the present invention
-In the vinylphenol unit, since the phenolic hydroxy group has an affinity for water and the phenyl group has an affinity for the alcohol component, and their balance is particularly good, the spread of the ink dots at the moment when the ink droplets land It is presumed that a very specific result was obtained as compared with other polymers, in which the ink density was appropriately controlled, and the ink dots ejected adjacently were appropriately fused to eliminate uneven density in the printed area.

Further, the polymer containing the p-vinylphenol unit in the present invention has a high affinity with the solvent in the ink, but has no ability to fix the dye. Therefore, all the dyes are quaternary salts of the ink absorbing layer. Since it is fixed to the contained polymer, it does not affect the water resistance of the recorded image. Further, the polymer containing the p-vinylphenol unit is insoluble in at least acidic to neutral water, and the adhesiveness to the ink absorbing layer when the silica fine particles are wet is not impaired.

Polymers containing at least one p-vinylphenol unit in the present invention include homopolymers thereof, as well as methacrylic acid and its esters, acrylic acid and its esters, styrenes and vinyl acetate and other vinyl esters. The copolymer of Further, in order to balance various characteristics and to match each ink, it is possible to mix and use these p-vinyl ester-containing polymers with other polymers. As the polymer, those soluble in alcohol are preferable from the viewpoint of solubility. Examples thereof include polyvinyl acetate and its copolymer, polyhydroxypropyl methacrylate and its copolymer, butyral resin and alcohol-soluble nylon.

The addition amount of these binder polymers to the silica fine particles is preferably 10% or more and 150% or less by weight. If it is less than 10% by weight with respect to the silica fine particles, the adhesive effect is weak and the particles easily fall off, which is not preferable. It is not preferable because fixation on the ink absorbing layer is hindered. Further, for the same reason, it is necessary to use such an adhesive polymer within a range not exceeding 0.3 g / m ² , and if the coating amount is more than this, a layer of such a polymer is likely to be formed on the surface and ink fixing, It is not preferable because it inhibits absorption and adversely affects the image.

The silica fine particles preferably have an average particle size of 1 micron or more and 5 microns or less. If the average particle size is less than 1 micron, the effect of giving unevenness to the surface is small and the effect of blocking prevention itself is small. Therefore, in order to prevent blocking, it is necessary to coat at a ratio exceeding 50% of the surface area, and thus gloss And transparency are deteriorated, which is not preferable. Also, when fine particles having an average particle size of more than 5 microns are used, the surface roughness becomes noticeable and it may also affect the resolution of the image, so the amount used is limited to a very small amount, and in some cases The surface area (coverage) may be less than 1%, and the blocking prevention effect may be insufficient. Therefore, it is preferable that at least 50% or more of the entire fine particles to be used fall within the range of 1 micron to 5 microns, and if a large number of particles with a small particle size of less than 1 micron are mixed, the anti-blocking property will be improved. May be deteriorated or gloss or transparency may be deteriorated, and if a large number of particles having a large particle size exceeding 5 microns are mixed, the surface may be roughened or the resolution may be adversely affected, which is not preferable.

The fine silica particles used in the present invention slightly absorb the dye in the ink, but the amount of the silica itself present on the surface is very small, so that it does not adversely affect the image and dye fixing property. Is a feature.

The object of the present invention can be achieved by providing an overcoat comprising fine silica particles and a binder containing a p-vinylphenol unit on an ink absorbing layer comprising a water-soluble polymer containing a quaternary salt. Further, it is possible to introduce other components into the overcoat for various purposes to further improve the properties. For example, various colloidal silica, alumina sol, polymer latex, various metal salts, it is possible to improve the properties by surface overcoating by the addition of metal oxides, etc., the amount of these additives is preferably equal to or less than the silica particles, If the amount added exceeds the amount of silica particles, undesirable effects such as a decrease in gloss and transparency may occur.

If the silica fine particles dispersed as described above are used to prevent blocking and improve stickiness, an ink absorbing fixing layer containing a water-soluble polymer having a quaternary ammonium salt group is provided thereunder, whereby the object of the present invention is basically. The polymer having such a quaternary ammonium salt group is, for example,
Alternatively, it is preferably a water-soluble polymer obtained by using at least a monomer selected from Chemical formula 3.

In the chemical formula ¹ , R ¹ represents hydrogen or a methyl group, and Q represents oxygen or an NH group. R ² ,
R ³ and R ⁴ represent a methyl group or an ethyl group, and may be the same or different. X represents a halogen ion, a sulfonate anion, an alkylsulfonate anion, an acetate anion, or an alkylcarboxylate anion. n represents an integer of 2 or 3.

In the chemical formula 2, R ⁵ , R ⁶ and R ⁷ represent a methyl or ethyl group and may be the same or different. X is the same as X in Chemical formula 1. In Chemical formula 3, R ⁸ ,
R ⁹ and R ¹⁰ represent a methyl, ethyl or allyl group and may be the same or different. X is the same as X in Chemical formula 1.

Preferred compounds among the monomers represented by Chemical formula 1 are, for example, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate and N, N-dimethylaminopropyl (meth). ) Acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide and N , N-Diethylaminopropyl (meth) acrylamide methyl chloride, ethyl chloride, methyl bromide, ethyl bromide, methyl iodide or a quaternary compound of ethyl iodide, or a sulfone substituted with anion thereof. Salts, alkyl sulfonates, can be exemplified acetates or alkyl carboxylates.

Of these, particularly preferred compounds include, for example, trimethyl-2- (methacryloyloxy) ethylammonium chloride, triethyl-2- (methacryloyloxy) ethylammonium chloride, trimethyl-2- (acryloyloxy) ethylammonium chloride, Triethyl-2- (acryloyloxy) ethylammonium chloride, trimethyl-3- (methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy) propylammonium chloride, trimethyl-2- (methacryloylamino) ethylammonium chloride, triethyl- 2- (methacryloylamino) ethylammonium chloride, trimethyl-2
-(Acryloylamino) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloylamino) propylammonium chloride,
Triethyl-3- (methacryloylamino) propylammonium chloride, trimethyl-3- (acryloylamino) propylammonium chloride, triethyl-3- (acryloylamino) propylammonium chloride, N, N-dimethyl-N-ethyl-2
-(Methacryloyloxy) ethylammonium chloride, N, N-diethyl-N-methyl-2- (methacryloyloxy) ethylammonium chloride, N,
N-dimethyl-N-ethyl-3- (acryloylamino) propylammonium chloride, trimethyl-
2- (methacryloyloxy) ethylammonium bromide, trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2-
Examples thereof include (methacryloyloxy) ethylammonium sulfonate and trimethyl-3- (acryloylamino) propylammonium acetate.

A preferable example of the monomer represented by Chemical formula 2 is trimethyl-p-vinylbenzylammonium.
Chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride, triethyl-m-vinylbenzylammonium chloride, N, N-dimethyl-N-
Ethyl-p-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-p-vinylbenzylammonium chloride, trimethyl-p-vinylbenzylammonium bromide, trimethyl-m-
Vinylbenzyl ammonium bromide, trimethyl-p-vinylbenzyl ammonium sulfonate, trimethyl-m-vinyl benzyl ammonium sulfonate, trimethyl-p-vinyl benzyl ammonium
Examples thereof include acetate and trimethyl-m-vinylbenzylammonium acetate.

Preferred examples of the monomer represented by Chemical formula 3 include diallyldimethylammonium chloride, diallyldiethylammonium chloride, diallyldimethylammonium bromide, diallyldimethylammonium sulfonate and diallyldimethylammonium acetate.

By introducing the quaternary ammonium base represented by Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3 into the water-soluble polymer, when it is contained in the ink absorbing layer, it exhibits an excellent dye fixing action and is preferably used. I can. Such a quaternary salt type polymer may be used in the form of forming an ink absorbing layer in combination with other pigments such as silica or other water-soluble polymers, but in the case where pigments are used in combination, transparency and gloss are not impaired. Limited to small additions. Also, when other water-soluble polymers are used in combination, the concentration of the quaternary salt type polymer in the layer may decrease and the dye fixing function may not be fully exerted. More preferred is a system that does not.

Further, as the above quaternary salt type polymer, those in which the monomer unit represented by Chemical formula 1, Chemical formula 2 or Chemical formula 3 is contained in the polymer within the range of 10 to 50 parts by weight are particularly preferable. The dye fixability and the ink absorbency are most preferably exhibited by the ratio, and in the range other than this, there is a problem that the dye fixability is deteriorated, the stickiness of the film may be extremely deteriorated, or the water resistance of the film itself may be inferior. May not be. Further, in addition to the monomer units selected from Chemical Formulas 1 to 3, the monomer units represented by Chemical Formula 4 are copolymerized in the range of 1 to 30 parts by weight, whereby the gloss of the film, the adhesion to the support, and the curl prevention It is very preferable because the performances such as

In the chemical formula 4, R ¹¹ represents hydrogen or a methyl group, and R ¹² and R ¹³ represent a methyl group or an ethyl group, which may be the same or different. Q represents oxygen or an NH group. n represents an integer of 2 or 3. Preferred examples of the monomer represented by Chemical formula 4 include N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropylacrylamide and the like.

In addition to these monomer units, acrylamide, methacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, diacetone acrylamide, N-methylol acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth). By copolymerizing a monomer selected from acrylate and N-vinylpyrrolidone in the range of 20 to 80 parts by weight, the ink absorption capacity and the ink absorption speed of the polymer having the quaternary ammonium salt group are increased, and the ink dot diameter is further increased. It gives extremely favorable properties such as adjusting to an appropriate size and eliminating uneven printing on solid parts.
When the amount of such a monomer unit used in the quaternary salt type polymer is less than 20 parts by weight, it is difficult to recognize such a preferable effect, and when it exceeds 80 parts by weight, the concentration of the quaternary base in the polymer is lowered and the ink fixing property is lowered. Function may deteriorate.

Further, as the quaternary salt type polymer, various copolymerizable monomers may be introduced in addition to the above monomer units, but they should be used within a range that does not impair the preferable effects due to the introduction of each of the above monomer units. It is usually preferably 30 parts by weight or less. Examples of such a monomer include styrene and its derivatives,
Examples thereof include various monomers such as acrylic acid ester, methacrylic acid ester, acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, fumaric acid, allylamine, diallylamine and vinyl ethers.

In particular, the above quaternary salt type polymer is very preferable in that it forms an ink absorbing layer substantially alone and such a polymer itself satisfies the ink absorbing property and the ink fixing property at the same time. It is preferable to keep the amount to the minimum even when the addition of an inorganic pigment such as silica or the use of other polymers is not necessary or required, and usually, the amount is less than 10% by weight based on the quaternary salt polymer. Is preferred because it does not impair the gloss and transparency. In order to obtain a recording material with particularly high glossiness, it is necessary to configure the surface gloss of the ink absorbing layer itself to a high level, and the glossiness measured at an angle of 60 degrees is at least as measured by the JIS standard glossiness measurement method. By exhibiting a value of 30 or more, a recording material having a glossy feeling can be obtained. Furthermore, when the glossiness of the ink absorbing layer itself is 70 or more, the glossiness is further enhanced, and even if the silica fine particles are sprinkled on the ink absorbing layer together with the adhesive polymer as described above, the glossiness is not significantly reduced. It is extremely preferable because it is not recognized. That is, the presence of silica fine particles on the surface inevitably reduces the glossiness to some extent, but if the surface gloss of the recording material is approximately 20 or more, the glossiness can be visually confirmed, and thus the surface gloss of such recording material can be confirmed. In order to keep the value of at least 20 or more, it is necessary to secure the glossiness of the ink absorbing layer itself to a value of at least 30. In this case, even if the silica fine particles are sprinkled on the surface for the first time, the surface gloss is a value of 20 or more. It is possible to keep As described above, in order to maintain the surface gloss of the ink absorbing layer itself to 30 or more, other additives such as inorganic particles such as silica in addition to the quaternary salt type polymer should not be introduced into the ink absorbing layer as much as possible. Even when it is preferably introduced, it is preferable that the amount is less than 10 parts by weight with respect to 100 parts by weight of the quaternary salt type polymer so that the surface gloss of the ink absorbing layer itself constituted by the quaternary salt type polymer is maintained at a value of 30 or more.

However, it is extremely preferable to add various curing agents in order to crosslink the quaternary salt type polymer to further improve the water resistance while improving the ink absorption capacity, and the curing agents used for such purpose. As
An epoxy-based curing agent represented by Chemical formula 13 is preferably used. In particular, by introducing an amino group as shown in Chemical formula 4 into a quaternary salt type polymer, it effectively acts as a cross-linking point for an epoxy curing agent and efficiently gives a three-dimensionally cross-linked water-resistant film. Is particularly preferable. The addition ratio of the epoxy curing agent to the quaternary salt type polymer is preferably in the range of 1 to 30 parts by weight with respect to the polymer. Below this range, crosslinking is insufficient and the effect is not recognized. Addition in excess of parts by weight is not preferred because the curing will proceed too much to form a highly crosslinked polymer and the ink absorption will be extremely reduced. The preferable amount of the epoxy curing agent is in the range of 1 to 10 parts by weight based on 100 parts by weight of the polymer.

[0037]

[Chemical 5]

[0038]

[Chemical 6]

[0039]

[Chemical 7]

(In chemical formula 7, n represents an integer of 2 or 3.)

[0041]

[Chemical 8]

[0042]

[Chemical 9]

[0043]

[Chemical 10]

[0044]

[Chemical 11]

[0045]

[Chemical 12]

(In chemical formula 12, m represents an integer from 1 to 22.)

[0047]

[Chemical 13]

(In Chemical formula 13, q represents an integer from 1 to 11.)

As described above, a quaternary salt type polymer appropriately three-dimensionally cross-linked with an epoxy type curing agent is used as an ink absorbing layer, and silica fine particles are added to the upper surface of this layer together with a polymer containing a p-vinylphenol unit. The particles are adhered to the surface in a discrete form to form a recording material having excellent ink absorbency and fixability and causing no blocking, and these have excellent surface gloss and have the above-mentioned properties on a transparent support such as a film. By providing the structure, the recording material for OHP is provided. These are particularly useful for multicolor recording, and one of the characteristics is that the water resistance is dramatically improved.

[0050]

The present invention will be described in more detail with reference to the following examples.

Examples 1 to 5 Polymers having the compositions shown in Table 1 were synthesized, and each polymer was made into a 10% by weight aqueous solution to give a dry film thickness on paper coated with polyethylene (RC paper). It was coated and dried to a thickness of about 10 microns. When the surface gloss of the formed ink absorbing layer was measured by a gloss meter (Gloss Checker, manufactured by Horiba Ltd.), a high gloss of 70 or more was shown in all cases. A coating liquid having the following composition is further applied as an overcoating liquid on this coating layer (wet coating amount)
Of 6 g / m ² and dried to obtain a recording material for ink jet.

Overcoat coating liquid blended silica fine particles (Sylysia 358 manufactured by Fuji Silysia Chemical Ltd., average particle size 1.8 micron) 1.0 g p-vinylphenol polymer (Maruka Linker M manufactured by Maruzen Petrochemical Co., Ltd.) ) 1.0 g methanol 70.0 g

The obtained recording material was printed using a full color ink jet printer pixel jet manufactured by Canon Inc. and the results shown in Table 2 were obtained.

Comparative Examples 1 to 5 As a comparison, the respective printing results when the above overcoat coating liquid was not applied are also shown in Table 2 as Comparative Examples.
In the comparative example, the printed dots did not spread uniformly, and remarkable density unevenness occurred in the solid image. On the other hand, in each of the examples, the surface gloss was 30 or more, the gloss feeling was excellent, the resolution and the printing density of the solid portion were uniform, and the blocking was not observed. Further, when the surfaces of the recording materials obtained in Examples 1 to 5 were observed by a scanning electron microscope, silica was present in a discrete form on the surface and the lower polymer layer was exposed between silica particles. Was confirmed. The surface coverage of silica was determined by an image analyzer to be about 22%.

[0055]

[Table 1]

In Table 1, DMAPAA-Q = 4 by methyl chloride of N, N-dimethylaminopropylacrylamide
Grade (trimethyl-3- (acryloylamino) propylammonium chloride), DMAEMA-Q = N, N-
Quaternary compound of dimethylaminoethyl methacrylate with methyl chloride (trimethyl-3- (methacryloyloxy) ethylammonium chloride), VBTMAC =
p-vinylbenzyltrimethylammonium chloride, DADMAC = diallyldimethylammonium chloride, AM = acrylamide, HEMA = 2-hydroxyethylmethacrylate, DMAPAA = N, N-dimethylaminopropylacrylamide.

[0057]

[Table 2]

Comparative Examples 6 to 10 Polymers 1 to 5 shown in Table 1 were coated on RC paper in the same manner as in Example 1 and dried, and then the following overcoat coating liquid was applied onto this coating layer to give a dry film thickness. Was applied and dried to prepare a recording material. Printing evaluation was performed on this, as in Example 1, and the results are shown in Table 3.

Comparison overcoat coating liquid formulation Silica fine particles (Sylysia 358) 10 g Polyvinyl alcohol (PVA103 manufactured by Kuraray) 8 g Pure water 100 g

When this recording material was printed, the solid part had good print quality, but the entire surface of the recording material was covered with silica, and the surface glossiness was less than 20 with no gloss and low resolution. It was a print result. Further, rubbing the surface of the recording material with a finger gives a powdery feel, which is not preferable.

[0061]

[Table 3]

Examples 6 to 10 Polymers 6 to 10 having the compositions shown in Table 4 were synthesized to make 10% by weight aqueous solution of each polymer, and 10 parts by weight of the epoxy curing agent shown in Chemical formula 5 was added to the polymer. An aqueous solution added by weight% was used as a coating liquid, and these were applied on a 100-micron-thick polyester film subjected to an aqueous undercoating treatment so that the dry film thickness was about 10 microns, and dried. 1 at a temperature of 40 ° C
After heating for 24 hours, a coating liquid of the following composition is further coated on this coating layer as an overcoat coating liquid so that the coating amount (wet coating amount) is 10 g / m ^2, and dried to use for ink jet. The recording material was used.

Overcoat coating liquid formulation Silica fine particles (Silicia 435 manufactured by Fuji Silysia Chemical Ltd., average particle size 2.5 micron) 1.0 g p-vinylphenol polymer (A) or copolymer (B)- (E) 1.5 g methanol 70.0 g

Here, the polymer of p-vinylphenol (indicated as polymer A in Table 5) is the same as in Example 1, and the copolymers (B) to (E) are (B) p. -Copolymer of vinylphenol and methyl methacrylate (molar ratio 1:
1), (C) copolymer of p-vinylphenol and styrene (1: 1), (D) copolymer of p-vinylphenol and styrene (7: 3), (E) p-vinylphenol And 2-hydroxyethyl methacrylate copolymer (1: 1) (Maruzen Petrochemical Co., Ltd. Maruka Linker CMM, CST50, CST70, CHM) were used. The surface of the obtained recording material is about 20 due to silica.
% Coating was performed using a full color ink jet printer pixel jet manufactured by Canon Inc., and the results shown in Table 5 were obtained.

Comparative Examples 11 to 15 For comparison, the following overcoat coating liquids were replaced by the overcoat coating liquids of Examples 6 to 10 in a wet coating amount of about 10 g /
except that coating m ² and so as in the same manner as in Example 6-10 to obtain an ink jet recording material, each of the print result is shown as a comparative example in Table 5.

Comparative overcoat coating liquid formulation Sylysia 358 5.0 g Poly (styrene-methyl methacrylate-methacrylic acid) (weight ratio 40:30:30) Copolymer (F) 5.0 g Methanol 50.0 g

In the case of Comparative Example, when the surface of the recording material was observed with a scanning electron microscope, 60% or more of the surface was covered with silica, and the surface of the silica particles was covered with a binder polymer. When the recording material obtained in the comparative example was subjected to the same printing evaluation, the ink absorption was poor and the ink was transferred to the guide roller due to the ink overflow, and the density at the solid part was not uniform and the image quality was poor. Was bad. In this case, the transparency of the recording material was also poor. On the other hand, all of the recording materials obtained in this example show good print quality and are excellent in transparency, and even if the recording material after recording is washed with water, no decrease in image density or peeling of the film occurs. It was extremely excellent in water resistance.

[0068]

[Table 4] In Table 4, IPAM = isopropylacrylamide, DMAEMA =
Represents dimethylaminoethyl methacrylate. Others are the same as in Table 1.

[0069]

[Table 5] In Table 5, polymers 6 to 10 and A to F represent the polymers used in the ink absorbing layer and overcoat, respectively.

The definitions of the evaluation methods and the evaluation results of the evaluation items in Tables 2, 3 and 5 are as follows. Uniformity of solid area Judgment was made visually with respect to each single color of yellow, magenta, cyan and black and their heavy colors. ◯: The ink did not overflow more and was uniform. X: The ink was smeared or overflowed and the surface was rough. Resolution Visually judge thin lines with line width and spacing of 125 μm. ○: The line and the line are clearly separated. X: The line looks thick and sticky due to bleeding. Gloss Judged visually and by glossiness. ◯: There is a glossy feeling, and the glossiness is 30 or more. X: There is no gloss and the gloss is less than 30. Blocking Property The front and back surfaces of the recording material are superposed, a pressure of 0.5 kg / cm ² is applied, and the recording material is left to stand in a room at 20 ° C. and 65% RH for 24 hours. ◯: No blocking. X: Blocking occurred. Water resistance Drop water on the printed image and wipe it off with a cloth after 1 minute. ◯: No peeling of the coating layer and no discoloration or bleeding of the printed image. X: Peeling of the coating layer or decolorization or bleeding of the printed image is recognized. Transparency Visual judgment. ◯: Transparent and the color saturation of the printed image is high. X: low transparency,
The printed image looks cloudy.

[0071]

According to the present invention, it is possible to obtain a water-resistant recording material for ink jet which has gloss and transparency, and in particular has less unevenness in the solid portion and excellent printing quality.

Claims (7)

[Claims] 1. An ink absorption layer containing a water-soluble polymer having a quaternary ammonium salt group is provided on a support, and silica fine particles and at least one p-vinylphenol unit are formed on the upper surface of the ink absorption layer. A recording material for ink jet recording, wherein a polymer as a component is present in an amount of 10% or more and 150% or less by weight with respect to the silica fine particles. 2. The polymer according to claim 1, wherein the polymer having a p-vinylphenol unit as at least one constituent component does not exceed 0.3 g / m ² , and the silica fine particles account for the total surface area of the ink absorbing layer. A recording material characterized by being present in a coverage of 5% or more and 50% or less. 3. The recording material according to claim 1, wherein the silica fine particles have an average particle size of 1 micron or more and 5 microns or less. 4. A water-soluble polymer having a quaternary ammonium salt group according to claim 1, which is a water-soluble polymer obtained by polymerizing at least a monomer selected from Chemical formula 1, Chemical formula 2, and Chemical formula 3. Recording material. [Chemical 1] (In Chemical Formula 1, R ¹ represents hydrogen or a methyl group, Q represents an oxygen or NH group. R ² , R ³ , and R ⁴ represent a methyl group or an ethyl group, and may be the same or different. X represents a halogen ion or a sulfonate anion, an alkyl sulfonate anion, an acetate anion, an alkyl carboxylate anion, and n represents an integer of 2 or 3.) (In Chemical Formula 2, R ⁵ , R ⁶ , and R ⁷ represent a methyl group or an ethyl group, and may be the same or different. X is the same as X in Chemical Formula 1.) (In Chemical Formula 3, R ⁸ , R ⁹ , and R ¹⁰ represent a methyl, ethyl, or allyl group and may be the same or different. X is the same as X in Chemical Formula 1.) 5. The water-soluble polymer having a quaternary ammonium salt group as defined in claim 1 or 4,
10 to 50 parts by weight of the monomer selected from 1 to 30 parts by weight of the monomer represented by Chemical Formula 4, and further water-soluble monomers such as acrylamide, methacrylamide, and N, N-
Dimethyl acrylamide, N-isopropyl acrylamide, diacetone acrylamide, N-methylol acrylamide, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, N
20 to 80 monomers selected from vinylpyrrolidone
A recording material, which is a water-soluble polymer obtained by copolymerization in the range of parts by weight. [Chemical 4] (In the chemical formula 4, R ¹¹ represents hydrogen or a methyl group, and R ¹² , R
¹³ represents a methyl group or an ethyl group, and may be the same or different. Q represents oxygen or an NH group. n represents an integer of 2 or 3. ) 6. The recording material according to claim 1, 4 or 5, wherein a three-dimensionally crosslinked ink absorbing layer is formed by adding an epoxy curing agent together with a water-soluble polymer having a quaternary ammonium salt group. Material. 7. The ink absorbing layer according to claim 1, which does not contain inorganic fine particles such as silica in a proportion of 10 parts by weight or more other than the polymer having the quaternary ammonium salt group, and the surface gloss of the ink absorbing layer is JIS standard. A recording material having a glossiness of 30 or more when measured at an angle of 60 degrees.