JPH07257015A - Material to be recorded for ink jet recording excellent in transparency and gloss - Google Patents

Abstract

PURPOSE:To provide a material to be recorded for ink jet recording imparting high-grade image quality excellent in ink absorbability and enhanced in gloss, transparency and water resistance. CONSTITUTION:An ink absorbing layer containing a water-soluble polymer having a quaternary ammonium base is provided on a support and a coating soln. containing spherical silica fine particles subjected to hydrophobic surface treatment and an alcohol-soluble polymer of which the amt is 5-150% by wt. of the spherical silica fine particles is applied to the upper surface of the ink absorbing layer so that the polymer is present in an amt. of below 0.3g/m<2> and spherical silica fine particles are present in a coating ratio of 1-50% of the total surface area of the ink absorbing 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 color recording image receptor having paper, resin-coated paper, film or the like as a support. .

[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.

Basic requirements for ink jet recording materials include high ink dot density, bright and vivid color tone, and large ink absorption capacity and high absorption speed, resulting in overlapping ink dots. 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 it becomes an opaque recording material that cannot be used for OHP. If colloidal silica is used instead of silica for the purpose of improving gloss and transparency, the method described in Japanese Patent Laid-Open No.
As described in the text of Japanese Patent Publication No. 157-157, it is not preferable because the ink absorbency is deteriorated. Alternatively, JP-A-3-215082, JP-A-4-67986, and JP-A-5-32
A method for forming a recording material having transparency by coating fine alumina sol with a water-soluble binder on the surface of a support as described in JP-A-037, etc., the alumina sol in the coating layer is described. (Pseudo-boehmite)
There is a problem that the ink absorbency is poor unless the ratio to the binder is increased, and such a coating layer having a high pigment ratio is very likely to cause cracking of the coating film during coating and drying, and the coating amount is 20 g / m2. If it is not about m ² , the ink absorption capacity is not sufficient, and therefore thick film coating is required, which makes it 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, polyvinylpyrrolidone-vinyl acetate copolymers described in JP-A-57-38185 and JP-A-62-184879, and JP-A-60. -1686
No. 51, No. 60-171143, No. 61-13429.
No. 0, No. 0,085, a binder containing polyvinyl alcohol as a main component, or JP-A-62-22038.
Acrylic polymer having a carboxyl group as disclosed in JP-A-3-2,382, and polyvinyl acetal polymer as disclosed in JP-A-4-214382 and JP-A-4-2822.
No. 82, No. 4-285650, various ink-absorbing polymers such as cross-linkable acrylic polymers have been proposed, but all of them are compatible with ink absorbency and water resistance of the coating film itself. Is difficult to
There is a problem that the recorded image is easily washed off when washed with water. In addition, in color image recording, the ink absorption capacity and absorption speed are still insufficient, and uneven mixing of each color ink occurs on the surface of the recording material, causing remarkable density unevenness especially 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 shows excellent print quality even in multicolor color recording and water resistance of a recorded image. The purpose is to increase

[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 spherical silica fine particles having a hydrophobic surface treatment on the upper surface of the ink absorption layer and the weight of the spherical silica fine particles. A coating liquid containing a polymer soluble in alcohol at a ratio of 5% or more and 150% or less,
The polymer is applied so that the polymer does not exceed 0.3 g / m ² and the spherical silica fine particles are present at a coverage of 1% or more and 50% or less of the total surface area of the ink absorbing layer. By forming a characteristic recording material for ink jet recording, a recording material having a desired ink absorbency and printing quality can be obtained.

The above-mentioned water-soluble polymer having a quaternary ammonium salt group is basically highly water-soluble and has the ability to absorb ink and retain it inside. However, it is usually used as an acid dye or a direct dye as a dye in the ink. Since a dye having a sulfonic acid group in the molecule is used in the molecule, a bond may be formed between the quaternary ammonium salt group and the quaternary ammonium salt in the form of ammonium sulfonate, and the dye may be bonded to the water-soluble polymer to be insolubilized. It is a feature. Therefore, the printed image has good water resistance, but conventionally, such a quaternary salt type polymer is not used alone as a dye fixing agent,
It has been used as an additive together with pigments and the like. In the present invention, such a polymer having a dye fixing action may be conventionally used in combination with other polymers, but rather, a polymer having a quaternary ammonium salt group as a dye fixing agent is mainly used for ink absorption. It has been found that the use as a binder is very preferable because the dye fixing action can be further increased. 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 ink is driven in, the dyes of the respective colors are quickly fixed, so that there is an advantage that the resolution of the recorded image is high. This fixing effect has been well known in the past, but since water-soluble polymers having a quaternary ammonium salt group absorb moisture in the air and become sticky, other polymers and inorganic pigments such as silica are 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, organic polymer fine particles are directly introduced into such an ink absorbing layer to improve the surface roughness by providing appropriate unevenness. In order to introduce the matting agent, it is inevitably necessary to keep the introduction amount at a low level, and in such a case, the surface of the matting agent itself is usually covered with the binder polymer, so that the quaternary salt type is used. When a polymer having high hygroscopicity 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 very likely to cause blocking is used as a binder component for absorbing ink, fine particles as a matting agent are directly introduced into a layer containing the polymer. Instead of this layer, by spraying spherical silica particles with a hydrophobic surface (hereinafter also simply referred to as “spherical silica particles”) on the upper surface of this layer in a separate form, blocking is very effectively prevented. I found what I could do.

Usually, silica is an inorganic substance having a knitting structure in which silicon atoms and oxygen atoms are three-dimensionally bonded. Hydrophobic surface-treated silica fine particles are those in which a part of oxygen atoms having a three-dimensional knitted structure is replaced with a hydrophobic group (for example, a hydrocarbon group such as a methyl group) and directly bonded to a silicon atom.
It is a substance having an intermediate structure between inorganic and organic.

One of the reasons for selecting the spherical silica fine particles having a hydrophobic surface treatment is that the solvent resistance is very strong, swelling is hardly observed even in an organic solvent such as alcohol, and the cohesiveness is small. They are uniformly dispersed, have no affinity with water-based inks used for ink jet recording, and have no adverse effect on image quality.

Such spherical silica fine particles are randomly present on the surface of the recording material and exhibit a good antiblocking effect only when they are present in a proportion of 1% or more of the total surface area. At this time, it is most effective that the fine particles are randomly distributed on the surface in a state where they are not aggregated with each other and are separated, and the fine particles are partially gathered in the order of several tens to 100 or more. It is not preferable that the particles are densely packed in such a state that blocking occurs on the surface where the fine particles do not exist. Further, when the spherical silica fine particles occupy more than 50% of the total surface area of the surface of the recording material, there is a problem that the surface gloss is remarkably lowered and the transparency is remarkably lowered although it has an antiblocking effect. Therefore, in order to obtain a recording material having high gloss and high transparency which is the object of the present invention, such spherical silica fine particles are preferably 1% or more and 50% or less of the total surface area of the ink absorbing layer. Further, in order to obtain higher gloss and transparency, it is preferable that the surface coverage of the spherical silica fine particles on the upper surface of the ink absorption layer is low, and the surface coverage of 1% or more and 30% or less prevents blocking. However, it is a very preferable range in order to secure high gloss and high transparency. Further, when the surface coverage is 10% or less, it is particularly preferable because the decrease in the gloss of the surface can maintain the gloss to the extent that it is hardly visually recognized. The coverage of the spherical silica fine particles on the surface of the ink absorbing layer is easily calculated from the formula of 1.5 × (coating amount) / (particle radius) from the average particle diameter and the numerical value of coating amount, For example, 0.3 g / m ^{2 of the} spherical silica particles having an average particle diameter of 3 μm
When the surface is covered with the coating amount of, the coverage is about 10%.

The present invention provides a recording material having a form in which spherical silica particles having a hydrophobic surface treatment are dispersed on the surface. The purpose of using the spherical silica particles having a hydrophobic surface treatment is generally to use an organic solvent. Since dispersion is extremely easy and dispersion stability is good, even when a liquid containing such fine particles is applied and dried, the particles are applied independently to the surface of the recording material and are unlikely to form an aggregated form. That can be cited as a merit. If spherical silica fine particles are aggregated and, in a remarkable case, a fine particle layer is formed on the surface of the recording material, ink absorption and ink wettability in this part are markedly deteriorated, which hinders ink absorption. However, it is extremely important that the spherical silica fine particles do not form a continuous layer because they may disturb the image.
Even if a plurality of particles of several tens or less are gathered together, the size of this portion needs to be 100 μm or less. Otherwise, the problem of causing unevenness in the image occurs. It is extremely important that the spherical silica fine particles are discretely or sea-island-distributed on the surface, and the surface of the lower ink absorbing layer is exposed to at least 50% of the entire surface.

The hydrophobic surface-treated spherical 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, but the adhesion to the surface is weak and the surface is rubbed. In that case, the fine particles easily fall off, so that permanent blocking is not performed, and when the surface is touched with a finger, a feeling of discomfort such as powderiness is felt, which is not preferable. Therefore, it is necessary to add an alcohol-soluble polymer as an adhesive agent for the spherical silica fine particles together with the spherical silica fine particles.

One of the reasons why the alcohol-soluble polymer is selected here is that high-boiling alcohols such as glycerin and ethylene glycol and various kinds are used in the water-based ink used for ink jet recording for the purpose of preventing clogging of nozzles. In many cases, a solvent such as alcohol is added, and the recording material has an affinity for not only water in the water-based ink but also such an alcohol component and needs to absorb these. The ink absorption layer itself needs to absorb the water that occupies most of the water-based ink, but at the same time it is also required to effectively absorb the alcohol component. Since it is extremely limited, as shown in the present invention, it is extremely preferable to add an alcohol-soluble polymer to the surface on which the ink droplets land so that the alcohol in the ink is absorbed to some extent immediately after printing. Furthermore, these alcohol-soluble polymers have a high affinity for ink, and this controls the spread of ink dots at the moment when ink droplets land, which allows ink dots that have been ejected adjacent to each other to reach a suitable level. It is possible to obtain a very preferable result that the density unevenness of the fused solid portion and the image line is eliminated.

Further, when the alcohol-soluble polymer is water-insoluble at the same time, the water resistance of a recorded image is greatly improved, which is extremely preferable.

The water-insoluble and alcohol-soluble polymer used for this purpose is not particularly limited, but the fine particles are added by a weight ratio of 5% or more and 150% or less to the hydrophobic surface-treated spherical silica fine particles. Various alcohol-soluble polymers can be used because the spherical silica fine particles are fixed on the surface and do not fall off from the surface even by friction or the like. In this case, 5 for the spherical silica fine particles.
If the amount is less than 1% by weight, the particles are not effective as an adhesive and the particles easily fall off, which is not preferable. On the contrary, if the amount is more than 150% by weight, a layer of such a polymer is formed around the particles and the ink absorbability at this portion is increased. Also, it is not preferable because the ink fixability is impaired. Further, for the same reason, it is necessary to use such an adhesive polymer in an amount that does not exceed 0.3 g per square meter, and if the coating amount exceeds this amount, a layer of such a polymer is apt to be formed on the surface and ink fixing and absorption are caused. Is unfavorable because it inhibits the image and adversely affects the image.

As the alcohol-soluble polymer, polymers having various structures can be used, and the degree of affinity to alcohol and the influence on the improvement of image quality due to the difference in structure are slightly different. On the other hand, as water-based inks used in commercial ink jet printers, inks with an extremely wide variety of compositions are used, and the required image qualities are also different, so it is optimal to match the printer to which it is actually applied. Alcohol-soluble polymers are selected.

As the polymer for adhering the spherical silica fine particles having the hydrophobic surface treatment to the surface of the ink absorbing layer, various alcohol-soluble polymers are preferably used as described above, but these polymers have an affinity for the alcohol in the ink. Since it has properties, it does not repel ink and contributes to improvement of image quality. In particular, the water-insoluble polymer is good even after washing with water, for example, since the spherical silica particles are made water resistant when the spherical silica treated with the hydrophobic surface is adhered and have a silica surface layer excellent in water resistance even after image recording. It is highly preferable because it exhibits a good anti-blocking effect. Such water-insoluble and alcohol-soluble polymers include polyvinyl acetate and its copolymers, acetal resins, ethylene-vinyl alcohol copolymers, alcohol-soluble nylons, polyhydroxyethyl methacrylate and its copolymers, polyhydroxypropyl. A polymer selected from methacrylate and its copolymers, polymethacrylic acid and its copolymers, polydiacetone acrylamide and its copolymers is particularly preferable because it shows good image quality and enhances the water resistance of the image. When an oil-soluble polymer or the like having a high hydrophobicity is used as a polymer other than the above-mentioned ones, it may be unfavorable because the water-based ink may repel and image unevenness may occur. When such a polymer is added in an amount of 0.3 g or more of square meter, the dye fixing property may be impaired because a part of the dye in the ink is absorbed by the polymer regardless of the kind of the polymer, which is not preferable. Furthermore, the best results are obtained in the range of 0.1 g or less of square meters.

Further, since the water-soluble and alcohol-soluble polymers have an affinity for both water and alcohol in the ink, they do not repel the ink and contribute favorably to the improvement of image quality. The treated spherical silica fine particles can be used as a polymer for adhering to the surface of a recording material. In particular, such polymers include polyvinylpyrrolidone and copolymers thereof, hydroxyethyl cellulose, hydroxypropyl cellulose, chitosan, polyacrylic acid and copolymers thereof,
Polymers selected from polyisopropyl acrylamide and copolymers thereof are preferably used. When an oil-soluble polymer or the like having a high hydrophobicity is used as a polymer other than the above-mentioned ones, it may be unfavorable because the water-based ink may repel and image unevenness may occur. When such a polymer is added in an amount exceeding 0.3 g of square meter, the dye fixing property may be impaired because a part of the dye in the ink is absorbed by the polymer regardless of the kind of the polymer, which is not preferable. Furthermore, the best results are obtained in the range of 0.1 g or less of square meters.

The hydrophobic surface-treated spherical silica fine particles have an average particle size of 1 micron or more and 10 microns or less, and have a high monodispersity and ± 20 of the average particle size.
Those in which 90% or more of the particles are present in a number range of 90% are preferably used. If the 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 may be added in a ratio of more than 50% of the surface area, so that the gloss This is not preferable because it causes deterioration in transparency and transparency. Further, when the spherical silica fine particles having an average particle diameter of more than 10 microns are used, the surface roughness becomes noticeable, and the resolution of the image may be affected. In some cases, the surface area (coverage) may be less than 1%, and the antiblocking effect may be insufficient. Therefore, it is preferable that the particle size distribution of the spherical silica fine particles to be used is substantially within the range of 1 micron to 10 microns, and if particles having a small particle size of less than 1 micron are mixed, the blocking prevention property is deteriorated. The gloss and transparency may decrease, and if particles with a large particle size exceeding 10 microns are mixed, the surface may be roughened or the resolution may be adversely affected. Therefore, when the particle size distribution is further sharp and 90% or more of the particles are present within the range of ± 20% of the average particle size, gloss and transparency are not deteriorated, and the resolution is effectively blocked without being adversely affected. It is extremely preferable because it can prevent

The hydrophobic surface-treated spherical silica fine particles used in the present invention do not show any interaction with the dye in the ink, and the amount of the alcohol-soluble polymer which plays a role of holding such fine particles on the surface is also small. Since it is a very small amount, it is characterized in that it does not adversely affect the image and dye fixing property.

The object of the present invention can be achieved by providing an overcoat on the surface of the recording material with a composition comprising spherical silica fine particles having the above hydrophobic surface treatment and an alcohol-soluble polymer. It is also possible to introduce other components for various purposes to further improve the properties. For example, various colloidal silica,
It is also possible to improve the properties by surface overcoating by adding alumina sol, polymer latex, various metal salts, metal oxides, etc., but the amount of these additives should be added to the spherical silica particles below this amount. Is preferable, and when an amount exceeding the spherical silica particles is added, undesirable effects such as deterioration of gloss and transparency may occur, which is not preferable.

The purpose of the present invention is to provide an ink-absorption fixing layer containing a water-soluble polymer having a quaternary ammonium salt group below the spherical silica fine particles which have been subjected to the hydrophobic surface treatment and are prevented from blocking as described above. Although it is basically achieved, examples of the polymer having such a quaternary ammonium salt group include those represented by the following chemical formula 1,
It is preferably a water-soluble polymer obtained by using at least a monomer selected from Chemical formula 2 or 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 is a halogen ion or a sulfonate anion, an alkylsulfonate anion, an acetate anion,
Represents an alkylcarboxylic acid 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 the 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. Among these, particularly preferable 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- Three
-(Methacryloyloxy) propylammonium chloride, triethyl-3- (methacryloyloxy)
Propyl ammonium chloride, trimethyl-2-
(Methacryloylamino) ethylammonium chloride, triethyl-2- (methacryloylamino) ethylammonium chloride, trimethyl-2- (acryloylamino) ethylammonium chloride, triethyl-2- (acryloylamino) ethylammonium chloride, trimethyl-3- (methacryloyl) Amino) 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- (methacryloyloxy) ethylammonium sulfonate,
Examples thereof include 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 salt group represented by the above Chemical Formula 1, Chemical Formula 2 or Chemical Formula 3 into the water-soluble polymer, when it is contained in the ink absorbing layer, an excellent dye fixing action is exhibited and it is preferably used. Can be done. 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 shown in 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 formula 4, R ¹¹ represents hydrogen or a methyl group,
R ¹² and R ¹³ represent 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. 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.

These monomer units are further selected from acrylamide, methacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, diacetone acrylamide, N-methylol acrylamide, 2-hydroxyethyl (meth) acrylate and N-vinylpyrrolidone. By copolymerizing the monomer in the range of 20 to 80 parts by weight, the ink absorption capacity and the ink absorption rate of the polymer having the quaternary ammonium salt group itself are increased,
Further, it imparts extremely preferable properties such as adjusting the ink dot diameter to an appropriate size and eliminating uneven printing on a solid portion. 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 can 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 because it forms an ink absorbing layer by itself, 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 is not necessary. Usually, the amount is usually 10% or less with respect to the quaternary salt type 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, the gloss of the ink absorption layer itself is 7
When the value is 0 or more, the glossiness is further increased, and even if the spherical silica fine particles having the hydrophobic surface treatment as described above are sprinkled on the ink absorbing layer together with the adhesive polymer, the glossiness is not significantly reduced. Is highly preferred. That is, the presence of the spherical silica fine particles on the surface inevitably lowers 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 such a recording material can be confirmed. In order to keep the surface gloss 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 or more. In this case, even if the spherical silica fine particles are sprinkled on the surface, the surface gloss is not increased. It is possible to keep the value at 20 or more. 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 10 parts by weight or less 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 kept at least 30 or more.

However, it is extremely preferable to add various curing agents in order to cross-link 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 the above, an epoxy type curing agent represented by Chemical formulas 5 to 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.

[0039]

[Chemical 5]

[0040]

[Chemical 6]

[0041]

[Chemical 7]

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

[0043]

[Chemical 8]

[0044]

[Chemical 9]

[0045]

[Chemical 10]

[0046]

[Chemical 11]

[0047]

[Chemical 12]

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

[0049]

[Chemical 13]

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

As described above, a quaternary salt type polymer, which is appropriately three-dimensionally cross-linked with an epoxy curing agent, is used as an ink absorbing layer, and spherical silica fine particles having a hydrophobic surface treatment and an alcohol-soluble polymer are further provided on the upper surface of this layer. Along with this, particles adhere to the surface in a discrete form to form a recording material that is excellent in ink absorbency and fixability and does not cause blocking, and these are excellent in surface gloss and on a translucent support such as a film. By providing the above structure, a 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.

[0052]

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

Examples 1-5 and Comparative Examples 1-5

Polymers 1 to 5 having the compositions shown in Table 1 were synthesized, and each polymer was used as an aqueous solution of 10% by weight to give a dry film thickness of about 10 on a paper (RC paper) whose surface was coated with polyethylene. It was coated and dried so as to have a micron size. The surface gloss of the formed ink absorption layer is measured by a gloss meter (gloss checker,
When measured by HORIBA, Ltd., a high glossiness of 70 or more was shown in each case. 2.0 parts by weight (weight ratio) of spherical silica fine particles (product name: Tospearl 120, manufactured by Toshiba Silicon) with an average particle diameter of 2.0 microns, which was subjected to a hydrophobic surface treatment as an overcoat coating liquid on this coating layer, and an acetal resin. (Product name: S-REC BM-2, manufactured by Sekisui Chemical Co., Ltd.) 0.5 parts (weight ratio) diluted with 97.5 parts (weight ratio) of methanol, the coating amount (wet coating amount) of the overcoat coating liquid is 6 g / m. ^It was coated so as to be ² and dried to obtain a recording material for ink jet.

The obtained recording material was used as a full-color ink jet printer Smart Jet 4012 manufactured by IRIS.
Printing was performed by using the above and the results shown in Table 2 were obtained. For comparison, the respective print results when the above overcoat coating liquid was not applied are also shown in Table 2 as Comparative Examples 1 to 5, but in the Comparative Example, remarkable blocking occurred. On the other hand, in all of the examples, the recording materials were good in terms of glossiness of 40 or more, excellent in glossiness, excellent in resolution, and free from blocking. Further, the surface coverage of the spherical silica fine particles subjected to the hydrophobic surface treatment was measured by an image analyzer and found to be 13%. The surface of the recording material obtained in the example was rubbed with a finger, but the spherical silica fine particles did not fall off, and the surface was smooth to the touch with a finger.

[0056]

[Table 1]

In Table 1, DMAPAA-Q = quaternary compound of dimethylaminopropylacrylamide with methyl chloride (trimethyl-3- (acryloylamino) propylammonium chloride), DMAEMA-Q = quaternary compound of dimethylaminoethylmethacrylate with methyl chloride Compound (trimethyl-2- (methacryloyloxy) ethylammonium chloride), VBTMAC = p-vinylbenzyltrimethylammonium chloride, DADMAC = diallyldimethylammonium chloride, AM = acrylamide, HEMA = 2-hydroxyethylmethacrylate, DMAP
AA represents dimethylaminopropyl acrylamide.

[0058]

[Table 2]

Examples 6 to 10 Polymers 6 to 10 having the compositions shown in Table 3 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 subjected to an aqueous undercoating treatment.
A polyester film having a thickness of micron was coated and dried so that the dry film thickness was about 10 microns. Spherical silica fine particles with an average particle diameter of 4.5 microns (product name: Tospearl 145, manufactured by Toshiba Silicon), which was heated at 40 ° C for one day and then subjected to hydrophobic surface treatment as a coating liquid for the overcoat on this coating layer. 2.0 parts (weight ratio) of alcohol-soluble polymers A to E, 0.5 parts (weight ratio) of methanol 9
The overcoat coating liquid diluted with 7.5 parts (weight ratio) was applied so that the applied amount (wet applied amount) was 10 g / m ^2, and dried to obtain 5 kinds of recording materials.

Here, as the alcohol-soluble polymer,
A = Polyacetal resin (Product name: S-REC BX-
5, Sekisui Chemical Co., Ltd., B = vinyl acetate-crotonic acid (95: 5 weight ratio) copolymer, C = alcohol-soluble nylon (Product name: Toresin EF-30T, Teikoku Chemical Co., Ltd.), D = ethylene-vinyl alcohol. Copolymer (Product name: Sowanol 3
0T, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., E = poly (2-hydroxyethyl methacrylate) was used.

The surface of the obtained recording material was covered with about 8% of spherical silica fine particles having a hydrophobic surface treatment, and printing was performed using a full color ink jet printer Smart Jet 4012 manufactured by IRIS. However, the results shown in Table 4 were obtained. The recording material obtained in this example shows good print image quality and transparency, and dye elution occurs even when a fixing property and a water resistance test such as dropping water droplets on the recorded image and rubbing with a finger are performed. The recording material was extremely excellent in water resistance. Similarly, a recording material having a recording layer of the same constitution provided on RC paper was prepared, but it showed the same good printing characteristics and water resistance, and had a glossiness of 30 or more, which was very excellent in gloss feeling. It was

[0062]

[Table 3]

In Table 4, IPAM = isopropylacrylamide and DMAEMA = dimethylaminoethylmethacrylate. Others are the same as in Table 1.

[0064]

[Table 4]

Comparative Example 6 Spherical silica fine particles having an average particle diameter of 2.0 μm (product name: Tospearl 120, manufactured by Toshiba Silicon), which was subjected to hydrophobic surface treatment instead of the overcoat coating liquid in Example 6 1
0 parts (weight ratio) and a vinyl acetate-crotonic acid copolymer (product name:
A recording material was obtained in the same manner as in Example 6 except that an overcoat coating liquid prepared by diluting 10 parts (weight ratio) of vinylol 30, manufactured by Showa High Polymer Co., Ltd. with 80 parts (weight ratio) of methanol was used.

In Comparative Example 6, when the surface of the recording material was observed with a scanning electron microscope, 70% or more of the surface was covered with the spherical silica fine particles and the surface of the fine particles was covered with the binder polymer. The recording material obtained in Comparative Example 6 had a gloss of 20 or less and was inferior in transparency. Further, as a result of printing evaluation in the same manner as in Examples 6 to 10, the dye was repelled by the binder polymer, the ink absorbability was extremely poor, and therefore the resolution and the image quality were also very poor.

Examples 11 to 15 Polymer 6 shown in Table 3 was used as a 10% by weight aqueous solution, and an aqueous solution containing 10% by weight of the epoxy curing agent shown in Chemical formula 5 was added as a coating solution. It was coated on a 100-micron-thick polyester film subjected to undercoating so that the dry film thickness was about 10 microns, and dried. 40
After heating for one day at a temperature of ℃, this coating layer was further subjected to hydrophobic surface treatment as a coating liquid for overcoat, and spherical silica fine particles with an average particle diameter of 3.0 microns (Product name: Tospearl 130, manufactured by Toshiba Silicon Co., Ltd. ) 1.6 parts (weight ratio) and water / alcohol-soluble polymers A to E, 0.4 parts (weight ratio) diluted with 98.0 parts (weight ratio) of methanol, coating amount (wet coating) Amount) is 10 g /
It was coated so as to have m ² and dried to obtain 5 kinds of recording materials.

As the water / alcohol-soluble polymer, A = polyvinylpyrrolidone, B = hydroxyethyl cellulose, C = chitosan, D = polyacrylic acid, E =
Acrylamide-N-isopropylacrylamide copolymer (2: 7 weight ratio) was used.

The surface of the obtained recording material was covered with the spherical silica fine particles in an amount of about 10%.
Printing was performed using a full-color ink jet printer Smart Jet 4012 manufactured by the company, and the results shown in Table 5 were obtained. The recording materials obtained in this example all 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, and the water resistance is high. It was extremely excellent.

Comparative Example 7 Spherical silica fine particles having an average particle diameter of 3.0 μm (product name: Tospearl 130, manufactured by Toshiba Silicon), which was subjected to hydrophobic surface treatment instead of the overcoat coating liquid in Example 11
Example 11 except that 1.6 parts (weight ratio) of water / alcohol-soluble polymer F and 10.0 parts (weight ratio) of the overcoat coating liquid diluted with 80.0 parts (weight ratio) of methanol were used. A recording material was obtained in the same manner.

As the water / alcohol-soluble polymer, F = styrene / methyl methacrylate / methacrylic acid (40:30:30 weight ratio) copolymer was used.

In Comparative Example 7, when the surface of the recording material was observed with a scanning electron microscope, 60% or more of the surface was covered with the spherical silica fine particles, and the surface of the spherical silica fine particles was covered with a binder polymer. It was The obtained recording material had a gloss of 20 or less and was inferior in transparency. Also, because the dye is adsorbed on the binder polymer,
Water resistance (bleeding of ink, decrease in image density) was poor.

[0073]

[Table 5]

The evaluation methods of the evaluation items in Tables 2, 4, and 5 and the definition of the evaluation results are as follows. Uniformity of solid area Visual judgment of single colors of yellow, magenta, cyan and black and their heavy colors. ◯: A uniform solid without any overflow of ink. ×: The ink is spilled or overflowed, and the surface is 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 becomes thick due to bleeding and appears to stick together. 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. Overlay the front and back of the recording material, 0.5kg / 100c
Apply a pressure of m ² and leave it in a room at 20 ° C and 65RH for 24 hours. ◯: No blocking. X: Blocking occurred. Water resistance ⊚: Immerse in 60 ° C. warm water for 1 minute. There is no peeling of the paint,
No discoloration or bleeding of the printed image is observed. ◯: Drop water on the printed image and wipe it off with a cloth after 1 minute.
There is no peeling of the coating layer, and no discoloration or bleeding of the printed image is observed. When immersed in warm water of 60 ° C. for 1 minute, the coating layer is partly peeled off. X: When water is dropped on the printed image and wiped off with a cloth after 1 minute, peeling of the coating layer or discoloration or bleeding of the printed image is recognized. Transparency Visual judgment. ◯: Transparent and the color saturation of the printed image is high. X: The transparency is low and the printed image looks cloudy.

[0075]

INDUSTRIAL APPLICABILITY According to the present invention, a recording material for ink jet recording having good gloss of printing quality and excellent transparency and having water resistance can be obtained.

Claims (7)

[Claims] 1. A spherical silica fine particle having a hydrophobic surface treatment on the upper surface of the ink absorbing layer having a water absorbing polymer having a quaternary ammonium salt group on a support, and the spherical silica fine particle. A coating solution containing a polymer soluble in alcohol in a proportion of 5% or more and 150% or less by weight is used in such a range that the polymer does not exceed 0.3 g / m ² and the spherical silica fine particles have a total surface area of the ink absorbing layer. 1%
A recording material for ink jet recording, characterized in that the recording material is applied so as to be present at a coverage of 50% or less. 2. The spherical silica fine particles having a hydrophobic surface-treated according to claim 1, having a particle size of 1 micron or more and 10 micron or less, and 90% or more of particles are present within ± 20% of the average particle size. A recording material characterized by being monodisperse fine particles. 3. The water-soluble polymer having a quaternary ammonium salt group according to claim 1 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, which may be the same or different. X represents a halogen ion or a sulfonate anion, an alkyl sulfonate anion, an acetate anion, an alkylcarboxylate anion, and n represents an integer of 2 or 3.) (R ⁵ , R ⁶ and R ^{7 in} Chemical Formula 2 represent a methyl or ethyl group and may be the same or different. X is the same as X in Chemical Formula 1.) (R ⁸ , R ⁹ and R ^{10 in} Chemical Formula 3 represent a methyl, ethyl or allyl group and may be the same or different. X is the same as X in Chemical Formula 1.) 4. The water-soluble polymer having a quaternary ammonium salt group according to claim 1 or 3 comprises 10 to 50 parts by weight of a monomer selected from Chemical formula 1, Chemical formula 2 and Chemical formula 3, and 1 to 1 of the monomer represented by Chemical formula 4. 30 parts by weight, and further selected as water-soluble monomer from acrylamide, methacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide, diacetone acrylamide, N-methylol acrylamide, 2-hydroxyethyl (meth) acrylate, N-vinylpyrrolidone. 20 monomers
A recording material, which is a water-soluble polymer obtained by copolymerization in the range of 80 to 80 parts by weight. [Chemical 4] (In the 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 is 2
Alternatively, it represents an integer of 3. ) 5. A recording material, characterized in that 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 according to claim 1, 3 or 4. 6. The ink absorbing layer according to claim 1, wherein the fine particles of silica or the like are not contained in an amount of 10 parts by weight or more with respect to the polymer having the quaternary ammonium salt group, in addition to the polymer having the quaternary ammonium salt group. A recording material, wherein the surface gloss of the ink absorbing layer is 30 or more when measured at an angle of 60 degrees according to the JIS standard. 7. The polymer soluble in alcohol, which is added together with the spherical silica fine particles having a hydrophobic surface treatment, according to claim 1, wherein the polymer is polyvinyl acetate and a copolymer thereof, an acetal resin, an ethylene-vinyl alcohol copolymer, Alcohol-soluble nylon, polyhydroxyethyl methacrylate and its copolymer, polyhydroxypropyl methacrylate and its copolymer, polymethacrylic acid and its copolymer, polydiacetone acrylamide and its copolymer, polyvinylpyrrolidone and its copolymer, A recording material, which is a polymer selected from hydroxyethyl cellulose, hydroxypropyl cellulose, chitosan, polyacrylic acid and its copolymer, polyisopropylacrylamide and its copolymer.