JPH08244333A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE: To obtain an ink jet recording sheet adapted to observe by projecting the transmitted light of a recording image to a screen by an optical equipment such as an OHP(overhead projector) to be used in a medium to be recorded used for a full color ink jet recording system in which ink amount to be given per unit area is increased. CONSTITUTION: The ink jet recording sheet comprises an ink passage layer made of silica sol and a non-water soluble binder dispersed in an organic solvent having a primary particle size of 10 to 100nm on at least one side surface of a base material, and an ink fixing layer formed by crosslinking copolymer having a quaternary ammonium salt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording medium used in a full-color ink jet recording system in which the amount of ink applied per unit area is large, and in particular, an OHP (which utilizes transmitted light of a recorded image). The present invention relates to an inkjet recording sheet suitable for being projected on a screen or the like by an optical device such as an overhead projector) for observation.

[0002]

2. Description of the Related Art The ink jet recording method has been attracting attention as a recording method capable of performing high-speed printing and multi-color printing with little noise and capable of easily performing full-color recording at low cost. The coloring material used in this recording method is mainly characterized by using a dye dissolved in an ink, that is, an aqueous medium.

A recording medium used for an OHP or the like is first required to have transparency and light transmissivity in view of its use. Naturally, a transparent film made of plastic or the like is used as a substrate for the recording medium. Therefore, unlike a paper or the like that can absorb, diffuse, and retain ink, it is necessary to provide some kind of ink fixing layer on the transparent base material. Various properties are required for this fixing layer. First, an ink absorption capacity that can sufficiently absorb the ejected ink droplets is required. In addition, in full-color printing, usually three or four different colors of ink are overprinted in a short time, so the ink absorption speed is very important so that the dots do not mix with each other. become. Next, in order to control the dot diameter of the ink, the wettability with respect to the ink is important, and the surface characteristics become a problem. Other properties required include dye color development, dye fixability, print density and light resistance, and transparency, blocking resistance, abrasion resistance, fingerprint resistance, etc. are required as OHP unique characteristics. .

Various methods have been taken to satisfy the above characteristics. For example, a recording material obtained by coating a transparent polymer film with silica particles and the like found in JP-A-56-157 and JP-A-57-14091 together with a water-soluble binder has been proposed. The absorption capacity and absorption rate have been obtained to some extent, but the transparency is poor due to the size of the particles, and water resistance cannot be expected because basically a water-soluble binder is used. Alternatively, JP-A-3-215082 and 4-
A recording material having transparency has been proposed by coating an alumina sol (pseudo-boehmite) with a water-soluble binder on the surface of a support as described in JP-A-67986 and JP-A-5-32037. Basically, a transparent porous layer is provided by using sol-gel transition to absorb ink,
Although it has a function such as absorption rate, because a large amount of binder cannot be introduced to the sol, cracks are likely to occur during the sol-gel transition, and it is possible to control drying conditions such as the speed of solvent removal during production. Very difficult.

As described above, the OHP sheet for ink jet is a recording material which is technically very difficult because it is required to have characteristics different from those for exclusive paper for ink jet or plain paper.

[0006]

DISCLOSURE OF THE INVENTION The present invention has a sufficient ink absorption rate and ink absorption capacity, and the coloring property of a dye,
Provided is an inkjet recording sheet which has good dye fixability, print density, print quality and water resistance, and has excellent surface wettability, blocking resistance, abrasion resistance, fingerprint resistance, and other surface characteristics and transparency. The purpose is to

[0007]

As a means for solving this problem, a primary particle size of 10 is provided on at least one surface of a substrate.
To 100 nm of an organic solvent-dispersed silica sol and an ink passage layer containing a water-insoluble binder, and an ink jet recording sheet having an ink fixing layer formed by crosslinking a copolymer having a quaternary ammonium salt. It Each of these will be explained in detail in turn.

A transparent plastic film is mainly used as the transparent substrate in the present invention. For example, polyester, polyolefin, polyamide, polyesteramide, polyether, polyimide, polyamideimide,
A film made of polystyrene, polycarbonate, poly-P-phenylene sulfide, polyether ester, polyvinyl chloride, poly (meth) acrylic acid ester is preferable, and a copolymer or blend of these or a cross-linked one can be used. . Polyester is more preferable, and among them, polyethylene terephthalate (hereinafter referred to as PET) is very preferable in terms of transparency, mechanical properties and workability. Also, in order to coat and adhere a water-soluble binder on this film, PET
It is more preferable that the film has a surface hydrophilized by undercoating treatment such as gelatin for improving adhesion or corona treatment.

In the present invention, an ink fixing layer containing a quaternary ammonium salt-containing copolymer is provided on at least one surface of the above-mentioned transparent plastic or other base material so as to have functions of ink absorption and dye fixing property. . This quaternary ammonium salt-containing copolymer basically has the following constitution, and is composed of a quaternary ammonium salt monomer component having a dye absorbing and fixing function, a monomer component that quickly absorbs ink, and a crosslinking agent. It is composed of three components, which are monomer components that form crosslinking points for three-dimensional crosslinking. Further, fourth and fifth monomer components for imparting other characteristics and functions may be introduced.

First, regarding the quaternary ammonium salt monomer component, an ink used in an ink jet printer is usually a water-based ink from the viewpoints of environment, safety, etc. Water-soluble dyes are commonly used. The water-soluble dye generally includes an acid dye in which a sulfonic acid group is introduced into the dye molecule to impart water solubility, a disperse dye, and a dye having water solubility by a carboxylate. The quaternary ammonium salt immediately binds to these sulfonates and carboxylates to fix the dye to the quaternary ammonium salt-containing copolymer.
It has long been known that such a quaternary ammonium salt has a dye fixing action, but generally, the quaternary ammonium salt is very water-soluble and easily absorbs moisture in the air and becomes sticky. However, it is preferable to make up for this defect by copolymerization with other monomer components. From the dye fixing property, the proportion of the quaternary ammonium salt monomer component in the whole copolymer is preferably 5 to 50% by weight,
Considering stickiness and the like, 10 to 30% by weight is preferable.

The quaternary ammonium salt monomer component used in the present invention is preferably a monomer selected from the general formulas 1, 2, or 3. In the general formula 1,
R ¹ represents hydrogen or a methyl group, Q is oxygen or N
Represents an H group. R ² , R ³ and R ⁴ represent an alkyl group having 1 to 6 carbon atoms, a benzyl group or an aryl group, and may be the same or different. X ⁻ represents a halogen ion, a sulfonate anion, an alkylsulfonate anion, an acetate anion, or an alkylcarboxylic acid anion. n is 2
Alternatively, it represents an integer of 3. In the general formula 2, R ⁵ , R ⁶ and R ⁷
Represents an alkyl group having 1 to 6 carbon atoms, a benzyl group or an aryl group, which may be the same or different. X ^-
Is the same as X ^{− in} Chemical formula 1. In the general formula 3, R ⁸ ,
R ⁹ and R ¹⁰ represent an alkyl group having 1 to 6 carbon atoms, a benzyl group, or an aryl group, and may be the same or different. X ^- X in the teeth of 1 ^- is the same as that.

The following are examples of the monomer represented by the general formula 1 having a quaternary ammonium salt in the present invention. For example, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, Methyl chloride, ethyl chloride such as N-dimethylaminoethyl (meth) acrylamide, N, N-diethylaminoethyl (meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide and N, N-diethylaminopropyl (meth) acrylamide , Quaternary compounds of methyl bromide, ethyl bromide, methyl iodide or ethyl iodide, or their anion-substituted sulfonates, alkyl sulfonates, acetates or alkyl carboxylates It can be mentioned.
Of 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-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) propyl ammonium
Chloride, trimethyl-3- (acryloylamino)
Propyl ammonium 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, Examples thereof include trimethyl-3- (acryloylamino) propylammonium bromide, trimethyl-2- (methacryloyloxy) ethylammonium sulfonate, and trimethyl-3- (acryloylamino) propylammonium acetate.

Preferred examples of the monomer represented by the general formula 2 are trimethyl-p-vinylbenzylammonium chloride, trimethyl-m-vinylbenzylammonium chloride, triethyl-p-vinylbenzylammonium chloride and triethyl-m-vinylbenzyl. Ammonium chloride, N, N-dimethyl-N-ethyl-p-vinylbenzylammonium chloride, N, N-diethyl-N-methyl-p-vinylbenzylammonium chloride, trimethyl-p-
Vinylbenzylammonium bromide, trimethyl-m-vinylbenzylammonium bromide, trimethyl-p-vinylbenzylammonium sulfonate, trimethyl-m-vinylbenzylammonium sulfonate, trimethyl-p-vinylbenzylammonium acetate, trimethyl-m-vinylbenzylammonium acetate, etc. Can be mentioned.

Preferred examples of the monomer represented by the general formula 3 are allyltrimethylammonium chloride, allyltriethylammonium chloride, allyltrimethylammonium bromide, allyltriethylammonium bromide, allyldimethylbenzylammonium chloride, allyldiethylbenzylammonium chloride and allyl. Examples thereof include dimethylbenzylammonium bromide, allyldiethylbenzylammonium bromide, diallyldimethylammonium sulfonate and diallyldimethylammonium acetate.

Next, the copolymerization component that quickly absorbs and retains ink will be described. As described above, the ink used in the inkjet printer is a water-soluble ink and most of its composition is water, but it contains non-volatile components such as glycerin and triethylene glycol to prevent the nozzles from drying. Is common. for that reason,
The ink image-receiving layer must instantly absorb and retain water and glycerin. Therefore, in order to have such a function, a copolymerizable component that is soluble or swells in water, alcohol, etc. is required. Examples of such a copolymer component include the following monomers. Acrylamide, methacrylamide, N, N-dimethylacrylamide, N, N-diethylacrylamide, N-isopropylacrylamide, diacetoneacrylamide, N-methylolacrylamide, N, N-
There are dimethylaminopropyl acrylamide, acryloylmorpholine, N-vinylpyrrolidone and the like.

By copolymerizing the above monomers in the range of 20 to 90% by weight, the ink absorption capacity and the ink absorption rate of the copolymer itself having the quaternary ammonium salt are increased, and ink dots are further added. It imparts extremely favorable properties such as adjusting the diameter to an appropriate size and eliminating uneven printing on solid parts. When such an amount of such a monomer used in the copolymer is less than 20% by weight, it is difficult to recognize a preferable effect.
On the other hand, if it exceeds 90% by weight, the concentration of the quaternary ammonium salt monomer component in the copolymer may decrease, and the ink fixing function may deteriorate. Therefore, further 50-85
The range of% by weight is more preferable.

Next, in order to further improve the water resistance of the quaternary salt ammonium salt-containing copolymer and improve the ink absorption capacity, it is preferable to three-dimensionally crosslink the copolymer.
A known reaction can be used as this crosslinking reaction. However, in the present invention, a method using an epoxy-based crosslinking agent, which is advantageous for the pot life of the coating liquid and the crosslinking reaction after coating the aqueous coating liquid, is preferable. That is, crosslinking is performed by providing a crosslinking point in the copolymer and adding an epoxy crosslinking agent.

Further, the addition ratio of the epoxy crosslinking agent to the quaternary ammonium salt-containing copolymer is preferably in the range of 10 to 300% by weight with respect to the monomer component forming the crosslinking point, and 10% is preferable. If it is less than 100 parts by weight, crosslinking is insufficient and its effect is small, and if it is more than 300% by weight, curing is excessively advanced and a highly crosslinked fixing layer is formed, so that absorption of ink is extremely lowered, which is not preferable. . The preferable amount of the epoxy crosslinking agent is in the range of 30 to 150% by weight with respect to the copolymer, and more preferably 30 to 100% by weight from the viewpoint of the ink absorption rate.

As the epoxy-based crosslinking agent used for the above purposes, various commercially available epoxy-based crosslinking agents can be used, and the epoxy-based crosslinking agent reacts with the epoxy-based crosslinking agent as a crosslinking point in the copolymer. A substance having a functional group is introduced. Of these, a carboxyl group, an amino group, a hydroxyl group and the like are preferable because they are easily introduced into the copolymer. In particular, the tertiary amino group is more preferable because it effectively acts as a cross-linking point for the epoxy cross-linking agent and gives a water-resistant film that is efficiently three-dimensionally cross-linked and has a long pot life. As the monomer component having such a tertiary amino group, those represented by the above general formulas 4, 5, and 6 are preferable. General formula 4
In the above, R ¹¹ represents hydrogen or a methyl group, and R ¹² and R ¹³ represent an alkyl group having 1 to 6 carbon atoms, a benzyl group or an aryl group, which may be the same or different. Q represents oxygen or an NH group. n represents an integer of 2 or 3. In the general formula 5, R ¹⁴ and R ¹⁵ represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a benzyl group or an aryl group, and may be the same or different. In the general formula 6, R ¹⁶ and R ¹⁷ represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a benzyl group or an aryl group, and may be the same or different.

Preferred examples of the monomer components represented by the general formulas 4 to 6 are N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate and N, N-dimethylamino. Propyl (meth) acrylate, N, N-diethylaminopropyl (meth) acrylate, N, N-dimethylaminopropyl (meth) acrylamide, N, N-diethylaminopropyl (meth) acrylamide, N, N-dimethylaminomethyl-p- Styrene, N, N-dimethylaminomethyl-m-styrene, N, N-diethylaminomethyl-p-styrene, N, N-diethylaminomethyl-m-styrene, N, N-dimethylallylamine, N,
Examples thereof include N-diethylallylamine, N, N-dipropylamine, N, N-dibutylallylamine, and N, N-dibenzylallylamine.

Further, by introducing a glycidyl group into the copolymer and adding a polyfunctional compound having a plurality of functional groups such as a carboxyl group, an amino group and a hydroxyl group, three-dimensional crosslinking can be achieved in the same manner as above. Can be achieved.

As described above, in the present invention, the quaternary ammonium salt copolymer and the epoxy crosslinking agent are added in an aqueous solution or in water.
An inkjet recording sheet suitable for OHP can be obtained by applying a solution, which is well mixed by stirring in an alcohol mixed solvent, onto a transparent plastic film which has been subjected to aqueous undercoating or corona treatment and dried. Various coating methods can be used, for example, bar coater, air knife coater, blade coater, roll coater, gravure coater, microgravure coater, fan ten reverse coater, spray coater, curtain coater, E-bar coater, comma coater, etc. Either method may be used without any particular limitation.

Further, the drying method may be any drying method as long as the water or alcohol is sufficiently evaporated under the drying condition that the plastic film as the base material does not hinder heat deterioration and the like to form a film. For example, a hot air drying oven, a drying drum, etc. can be used. The ink fixing layer in the present invention preferably has a dry coating amount of 3 g / m ² or more. 3 g /
If it is less than m ² , ink cannot be sufficiently absorbed and liquid overflows,
When the mixed colors are ejected, different inks often mix not as dots but as droplets, and a good color image cannot be obtained in many cases. Further, the upper limit of the coating amount of 3 g / m ² or more depends on the drying ability of the coater and the cost, and does not cause a problem characteristically as an inkjet image receptor.

As described above, in the present invention, since the ink fixing layer is basically formed by three-dimensionally cross-linking the water-soluble polymer of the quaternary salt ammonium salt-containing copolymer, the coloring property of the dye and the dye fixing property are obtained. , Water resistance and transparency are very good. On the other hand, the blocking property, abrasion resistance, fingerprint resistance, etc. derived from the water-soluble polymer are poor, and the surface contact angle to water is unexpectedly high, and the ink droplets that are ejected do not spread sufficiently and the print density Has brought about a decline. Therefore, an ink-passing layer using an organic solvent-dispersed silica sol solves these problems. This will be described below.

In the present invention, as a means for solving the above-mentioned problems, another layer of silica sol particles having an average particle diameter of 10 to 100 nm dispersed in an organic solvent is further contained on the three-dimensionally crosslinked copolymer-containing ink fixing layer. I will provide an ink passage layer. The layer formed by using those having this particle size range is porous, and the ink droplets hit on the surface spread instantly and are quickly absorbed by the capillary phenomenon, pass through the layer, and pass through the layer of the lower layer. Reaching and absorbing the polymer ink fixing layer,
It is fixed. The silica sol particles have an average particle size of 10 to 10.
Since the wavelength is 100 nm, which is shorter than the wavelength of light, it has very good light transmittance and is suitable as an OHP sheet. If 10n
If silica sol particles having a particle size of less than m are used, a dense film is formed and the ink absorption speed becomes slower, while if it exceeds 100 nm, the light transmittance becomes poor. Furthermore, since this silica sol layer is an inorganic oxide, it has very good blocking resistance against an OHP sheet, a clear file for storage, etc., and forms a surface with a smooth feel.

However, it is very difficult to form the above-mentioned layer of very small silica sol particles of nm order on the copolymer fixing layer. That is, when an ordinary colloidal silica dispersion aqueous solution is applied to an ink fixing layer obtained by three-dimensionally crosslinking the quaternary ammonium salt-containing copolymer, cracks are generated. Even if various examinations such as drying conditions, coating amount, and binder are performed, large and small cracks occur in the film. Such cracks are very unsuitable for an inkjet image receptor. This is because the ejected ink spreads along the cracks due to the capillary phenomenon, and a phenomenon called so-called feathering occurs and the ink bleeds. Also, OH
In an image receptor such as a P sheet, where light transmittance is important, even a small crack that is invisible and does not cause feathering causes light diffusion or the like and adversely affects light transmittance. Therefore, it is necessary to form a film of colloidal silica without any cracks. Furthermore, it is difficult to similarly apply an organic solvent-dispersed silica sol onto the copolymer-containing ink fixing layer or other water-soluble polymer-containing ink fixing layer according to the present invention, which is not three-dimensionally crosslinked, and it is difficult to obtain transparency. It is not possible to form an ink-passing layer of high clean silica sol.

As described above, regardless of the copolymer-containing ink fixing layer, it is very difficult to form a film on a base material that absorbs water very easily without cracking with silica sol dispersed in water. Difficult to do. Therefore, as a result of intensive studies, in order to form a silica sol film without cracks on the superabsorbent polymer layer, a three-dimensional structure is formed by crosslinking the lower ink fixing layer and an organic solvent is used as an overlayer. It was found that it is very effective to use dispersed silica sol. Further, it has been found that various properties such as color development, transparency, blocking resistance, abrasion resistance, fingerprint resistance, and water resistance of the dye required for the ink jet OHP sheet can be satisfied.

The colloidal silica layer using the organic solvent-dispersed silica sol will be described below. Usually, colloidal silica dispersed in an organic solvent is called an organosilica sol, which is clearly distinguished from colloidal silica dispersed in water.
As a manufacturing method, silicic acid alkoxide, that is, by hydrolysis in an organic solvent such as ethanol such as ethyl silicate solution,
A dispersion of ultrafine particles dispersed in an organic solvent is obtained. Further, as another method, there is a solvent substitution method obtained from a water-dispersed silica sol. The silica sol thus obtained has a good dispersibility in an organic solvent and is different from the surface state of ordinary water-dispersed colloidal silica. That is, the amount of hydroxyl groups on the surface of colloidal silica is smaller than that of water-dispersed colloidal silica. Therefore, compared with the ink passage layer formed of water-dispersed colloidal silica, the ink passage layer formed of organosilica sol quickly absorbs ink due to the capillary phenomenon due to the porosity and forms an ink fixing layer without trapping the ink in the passage layer. Can be carried.

An organic solvent used for the organosilica sol. The silica sol is stably dispersed and can be evaporated and dried at a temperature at which the plastic film does not deteriorate during drying after coating, and the lower ink fixing layer does not absorb it as much as possible. Organic solvents are preferred. Almost any commercially available organic solvent-dispersed silica sol can be used, and an organic solvent-dispersed silica sol dispersed in a solvent having a high boiling point or methanol that can be absorbed in a small amount by the copolymer ink fixing layer is also a suitable organic compound. It can be used by mixing the solvent.
Examples of such organic solvents include isopropanol, n-propanol, isobutanol, tert-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, 1,4-dioxane, diethylene glycol methyl ether, diethylene glycol ethyl ether, propylene glycol monomethyl ether. Acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diacetate and the like are highly preferred.

Further, although the fine structure of the film formed varies depending on the solvent used, a film made only of silica sol has poor film strength, so that it is inferior in abrasion resistance, fingerprint resistance and water resistance. Therefore, a binder is necessary in order to have sufficient film strength and enhance the adhesion to the ink fixing layer below. As the binder, various binders can be used, but a binder that is soluble in the coating solvent is basically preferable. The amount of the binder used is preferably 5 to 300% by weight based on the silica sol solid content. The amount used varies depending on the type of binder, but if it is less than 5% by weight, sufficient film strength and adhesion cannot be obtained, and if it exceeds 300% by weight, a tough film is formed, but a binder soluble in organic solvents. However, a good image cannot be obtained because the ink is repelled or the ink does not pass through the silica layer (ink passage layer) to reach the ink fixing layer below. A more preferable amount is 10 to 200% by weight.

It is preferable to apply the above-mentioned organic solvent-dispersed silica sol in a solid content of 0.05 to 15 g / m ² .
If the amount is less than 0.05 g / m ² , the silica layer is too thin and the ink dots do not spread sufficiently to reach the lower ink fixing layer, so that a sufficiently wide dot cannot provide a sufficient image density. In addition, blocking resistance is also deteriorated. Conversely,
When it exceeds 15 g / m ² , the silica layer becomes thick and the ink does not pass through the silica layer to reach the ink fixing layer below, so that the water resistance is not exhibited. Also, if the coating amount is too large, cracks will occur at the time of coating as in the case of the water-dispersed silica sol. The coating amount varies depending on the components of the ink or the absorbability of the ink fixing layer, but a more preferable coating amount is 0.05 to 10 g / m ² , and further 0.05 to 7 g.
/ M ² .

Such a silica layer can also be coated by various coating methods similar to the coating of the ink fixing layer. However, since an organic solvent is used as a coating solvent, it is preferable to apply it with a solvent coater equipped with explosion-proof equipment. Further, as the coating solvent, methanol, ethanol, isopropanol, and n- are used as in the dispersion solvent of the organosilica sol described above.
Propanol, isobutanol, tert-butanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, tetrahydrofuran, 1,4-dioxane, diethylene glycol methyl ether, diethylene glycol ethyl ether, propylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diacetate. Etc. are very preferably used.

[0033]

EXAMPLES Next, the present invention will be specifically described by way of examples, but the invention is not limited thereto.

Synthesis of Copolymer Used in Ink Fixing Layer Trimethyl-3- (acryloylamino) propylammonium chloride 10 g, acrylamide 60 g,
25 g of N, N-dimethylacrylamide, 5 g of dimethylaminopropylacrylamide and 350 ion-exchanged water
g, 50 g of isopropyl alcohol were charged into a 1 L four-necked flask, neutralized with an aqueous hydrochloric acid solution, heated, stirred, and purged with nitrogen, and 1 g of a polymerization initiator V-50 (manufactured by Wako Pure Chemical Industries, Ltd.) at about 60 ° C. Is charged to start the polymerization. Then 6
Polymerization was carried out for a time to obtain the intended copolymer 1. Copolymers 1 to 4 shown in Table 1 were obtained by the same synthesis method.

[0035]

[Table 1]

Each character in Table 1 represents the following. DMAPAA-Q; quaternary compound of dimethylaminopropylacrylamide with methyl chloride (trimethyl-3-
(Acryloylamino) propylammonium chloride) -DMAPAA; dimethylaminopropylacrylamide-AM; acrylamide-DMAM; N, N-dimethylacrylamide-ACMO; acryloylmorpholine

Preparation of Ink Passing Layer Coating Liquids Ink passing layer coating liquids A to E having the formulations shown in Table 2
Was prepared as a coating liquid. Especially for coating liquids D and E, water as a dispersion solvent is removed by evaporation with an evaporator or the like,
Obtain solid silica. This was dispersed in ethanol with a binder using a homomixer (10000 rpm, 30 minutes) to prepare a coating liquid.

[0038]

[Table 2]

Each character in Table 2 indicates the following.・ MA-ST-M; Nissan Chemical Co., Ltd. organo silica sol (40% by weight of silica sol solid content, methanol dispersion, average particle size 20-25 nm) ・ Snowtex 40; Nissan Chemical Co., Ltd. silica sol (silica sol solid 40% by weight, water dispersion, average particle size 10-20 nm)
Mosquito solid content-PST-3; Silica solid content obtained by evaporating the water content of a silica sol manufactured by Nissan Kagaku Co., Ltd. (silica sol solid content 20% by weight, aqueous dispersion, average particle size 300 nm) -BR-88; Acrylic binder made by Mitsubishi Rayon Co., Ltd.-ASR-09; Vinyl acetate binder made by Denki Kagaku Co., Ltd.-PVA-117; Polyvinyl alcohol made by Kuraray Co., Ltd.-MEK; Methyl isobutyl ketone-EtOH; Ethyl alcohol-IEW Ion-exchanged water

Examples 1 to 8 Each of the copolymers 1 and 2 shown in Table 1 was used as a 10% by weight aqueous solution, and an epoxy crosslinking agent (EX-521 manufactured by Nagase Kasei Co., Ltd.) was added to the polymer in an amount of 5%. % Aqueous solution was added as a coating liquid, and these were subjected to an aqueous undercoating treatment.
Dry coating amount is about 1 on 0 micron thick PET film
Coated with a wire bar to 0 g / m ² and 80 ℃
And dried for about 10 minutes. Then, the mixture was heated at a temperature of 40 ° C. for one day to allow crosslinking with an epoxy crosslinking agent to proceed sufficiently.
Onto this coating layer, the coating liquids shown in Table 2 as coating liquids for the ink passage layer were coated with a wire bar in the combinations shown in Table 3 to obtain an inkjet recording sheet.

[0041]

[Table 3]

Comparative Examples 1 to 13

[0043]

[Table 4]

Comparative Examples 1 to 11 are epoxy crosslinking agents EX-5
Copolymers 1 to 4 shown in Table 1 were coated on a PET film in the same manner as in Example except that No. 21 was not added and the ink passage layer was coated as shown in Table 4 to compare with Comparative Example. did. Comparative examples 12 and 13 are PVA-117 and 10%.
Dry coating amount of heavy aqueous solution on PET film is about 10g
/ M ² was applied with a wire bar and dried at 80 ° C. for about 10 minutes to provide an ink fixing layer, and an ink passage layer was applied as shown in Table 4 to give a comparative example. The inkjet recording sheet obtained as described above was subjected to printing evaluation and other evaluations. For printing evaluation, a personal computer PC-9801BX manufactured by NEC Corporation was connected to a bubble jet printer BJC-600j manufactured by Canon Inc., and various patterns (yellow, magenta, cyan, black, and solid colors of blue, green, and red) were mixed. Etc.) to OHP
Printed and recorded in the mode.

The evaluation methods of the evaluation items in Table 5 below and the definition of the evaluation results are as follows. -Cracks The presence or absence of cracks in the ink passage layer and the printed image area immediately after coating and drying was visually judged or microscopically judged. ◯: There are cracks, ×: There are no cracks. -Solidness uniformity Visual judgment of each single color of yellow, magenta, cyan and black and their mixed colors. ◯: Solid solid with little ink overflow, ×: Solid ink spilled or overflowed. -Density of solid part The optical density of black was measured by a transmission Macbeth densitometer.・ Resolution Visually judge thin lines with a line width and spacing of 125 μm. ◯: Lines are clearly separated, Δ: Lines are not connected to each other, but lines are clearly thick, ×: Lines are thick and sticky due to bleeding. -Dot diameter The printed area on which 1 dot of black was printed was observed with a transmission microscope to measure the dot diameter. The unit is micron.・ Haze The haze value is measured with NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd. ・ Water resistance Water is dropped on the printed image, and after 5 minutes, it is wiped off by rubbing with a cloth to visually judge the state of the coating layer surface. ◯: No peeling of the coating layer and no discoloration or bleeding of the printed image. X: Peeling of the coating layer or discoloration or bleeding of the printed image is recognized. -Fingerprint resistance With your thumb, press the thumbprint on the image receiving surface as strongly as you can and visually judge the state of fingerprints. ○: No fingerprint is attached. △:
Fingerprints are attached but can be removed by wiping. X: The fingerprint pattern is strongly attached and cannot be wiped off.・ Blocking resistance 0.5kg / 100c when two recording materials are superposed on each other.
After applying a pressure of m ² and leaving it in a room at 20 ° C and 65% RH for 24 hours, peel it off and observe the occurrence of blocking. ○:
No blocking, △: Blocking occurred only on the edge part, ×: Blocking occurred on the entire surface.

[0046]

[Table 5]

[0047]

According to the present invention, the ink absorption speed and the ink absorption capacity are sufficient, and the dye color developability, dye fixability, print density, print quality and water resistance are good, and the surface wettability and blocking resistance are good. It is possible to obtain an ink jet recording sheet suitable for OHP, which has excellent surface properties such as resistance, abrasion resistance, and fingerprint resistance and transparency.

Claims (5)

[Claims] 1. An ink passage layer containing a silica sol having a primary particle diameter of 10 to 100 nm dispersed in an organic solvent and a water-insoluble binder, and a copolymer having a quaternary ammonium salt on at least one surface of a transparent substrate. An ink jet recording sheet having an ink fixing layer formed by crosslinking. 2. The ink jet recording sheet according to claim 1, wherein the ink passage layer is formed by applying an organic solvent coating liquid. 3. A copolymer having a quaternary ammonium salt is a copolymer obtained by polymerizing at least a monomer represented by the following general formula 1, chemical formula 2, or chemical formula 3. The inkjet recording sheet according to claim 1 or 2. Embedded image (In Chemical formula ¹ , R ¹ represents hydrogen or a methyl group, Q represents oxygen or an NH group. R ² , R ³ , and R ^{4 each} have 1 to 6 carbon atoms.
Represents an alkyl group or a benzyl group, an aryl group,
It may be the same or different. X ⁻ represents a halogen ion, a sulfonate anion, an alkylsulfonate anion, an acetate anion, or an alkylcarboxylic acid anion. n represents an integer of 2 or 3. ) (Formula 2 in R ^5, R ^6, R ⁷ is an alkyl group or a benzyl group having 1 to 6 carbon atoms, an aryl group, which may be optionally substituted by one or more identical .X ^- X in the tooth of 1 ^- The same as). (Formula 3 in R ^8, R ^9, R ¹⁰ is an alkyl group or a benzyl group having 1 to 6 carbon atoms, an aryl group, which may be optionally substituted by one or more identical .X ^- X in the tooth of 1 ^- Is the same as.) 4. The ink jet recording according to claim 1, 2 or 3, wherein the copolymer having a quaternary ammonium salt contains a monomer represented by the following general formula 4, chemical formula 5 or chemical formula 6. Sheet. [Chemical 4] (In the formula 4, R ¹¹ represents hydrogen or a methyl group, and R ¹² , R ¹³
Represents an alkyl group having 1 to 6 carbon atoms, a benzyl group or an aryl group, which may be the same or different. Q represents oxygen or an NH group. n represents an integer of 2 or 3. ) [Chemical 5] (In Chemical Formula 5, R ¹⁴ and R ¹⁵ represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a benzyl group, or an aryl group, and may be the same or different.) (In Chemical Formula 6, R ¹⁶ and R ¹⁷ represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a benzyl group, or an aryl group, and may be the same or different.) 5. A three-dimensionally crosslinked ink absorbing layer is formed by adding an epoxy crosslinking agent together with a copolymer having a quaternary ammonium salt. The inkjet recording sheet described above.