JPH08230309A - Ink jet recording sheet - Google Patents

Abstract

PURPOSE: To provide an ink jet recording sheet high in coating layer strength and excellent in ink absorbability. CONSTITUTION: In an ink jet recording sheet wherein at least one or more ink receiving layer is provided on the single surface or both surfaces of a support, noncrystalline silica by an indirect method is added to the ink receiving layer in an amt. of 15-100% by wt. of the total amt. of the inorg. component constituting the ink receiving layer. By this method, the ink jet recording sheet high in coating layer strength and excellent in ink absorbability is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet for recording with ink, and in particular, the ink receiving layer provided on the ink jet recording sheet has a high coating layer strength and is excellent in ink absorbability. The present invention relates to an excellent inkjet recording sheet.

[0002]

2. Description of the Related Art The ink jet recording system is a system in which minute droplets of ink are ejected by various operating principles to adhere to a recording sheet such as paper to record images, characters, etc., but at high speed and low noise. It has features such as easy multicoloring, great flexibility in recording patterns, and no need for development-fixing. It is used in various applications as a recording device for various figures and color images including complicated characters such as Chinese characters. It is spreading rapidly. Further, an image formed by the multicolor ink jet system can obtain an image quality having gradation equivalent to that of the multicolor printing by the plate making system or the printing by the color photographic system. Further, in applications requiring a small number of copies, it is being widely applied to the full-color image recording field because it is cheaper than the photographic technique.

As an ink jet recording sheet having these characteristics, a coat type ink jet recording sheet having an ink receiving layer provided on a support surface such as high quality paper, synthetic paper, synthetic resin film, etc. has been developed so far. It was

An ink jet recording sheet used in the ink jet recording system is required to have basic printing characteristics such as excellent printing quality and high storability. The coating strength of the ink receiving layer is an important characteristic among such required characteristics. That is, if the coating layer strength is low, peeling or missing of the coating layer is likely to occur at the time of printing in the printer, and not only the printing quality is deteriorated, but also debris of the receiving layer that is peeled off or missing pollutes the printer, and also in terms of transport performance It becomes a serious obstacle. Further, peeling or missing of the coating layer may occur due to an unexpected stimulus in daily handling other than the printer printing process, and it is important to increase the coating layer strength.

The ink receiving layer is a coating layer obtained by applying and drying a coating liquid for the ink receiving layer obtained by adding a binder to a dispersion liquid of an inorganic pigment on a support, and absorbing the ink to fix it as an image. It is provided for that purpose. As the inorganic pigment contained as the main component in the ink receiving layer,
Many porous inorganic pigments are used in consideration of ink receiving ability, and porous synthetic amorphous silica, porous magnesium carbonate, porous alumina, etc. are widely used.

[0006] When using such a porous pigment, the coating layer strength is a problem. In other words, polyvinyl alcohol, latex emulsion, starch, etc., which are commonly used as binders, penetrate into the pores of particles because each single module when dispersed in a continuous layer is much smaller than the pore size of the particles. To do. Therefore, the binder that should originally contribute to the bond between the particles is trapped in the pores of the particles, and the coating layer strength is low as compared with the case of using the same amount of the binder as the case of the particles having no pores. turn into. Further, when the amount of the binder is increased for the purpose of increasing the strength of the coating layer, the pores of the particles are filled with the binder, and a sufficient ink absorption capacity cannot be obtained.
Therefore, under the present circumstances, it is difficult for an inkjet recording sheet formed by coating a porous pigment to satisfy both the ink absorption capacity and the coating layer strength, which are important as required properties.

As a means for increasing the coating layer strength, Japanese Patent Publication No.
As disclosed in JP-A-4-065792, JP-A-62-268682 and JP-A-63-118286, silanol-modified polyvinyl alcohol is used as a binder, or JP-A-04-07189. Like, using zirconium salt as a dispersant,
Further, as disclosed in Japanese Patent Laid-Open No. 63-120194, various methods using starch or latex as a binder have been tried.
On the other hand, although the coating layer strength is increased, the print density is lowered, the ink absorbency is lowered and the sharpness of the printed image is lowered, and it is currently difficult to obtain a high quality inkjet recording sheet. It was

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an ink having high ink absorption and strong coating layer strength, which was difficult with an ink jet recording sheet having an ink receiving layer composed of a conventional porous pigment and a binder. The purpose is to obtain an inkjet recording sheet having a receiving layer.

[0009]

The ink jet recording sheet of the present invention is characterized by containing amorphous silica by the indirect method in an amount of 15 to 100% by weight based on the total amount of inorganic components constituting the ink receiving layer. However, it is characterized by high ink absorbency and strong coating strength of the ink receiving layer.

The "indirect method" for amorphous silica by the indirect method means that amorphous silica is wet-processed as described in Tokuyama Handbook published by Tokuyama Corporation (October 1981) as Tokuyama process. It is one of the manufacturing methods. In the direct method, sodium silicate is directly decomposed with an acid, whereas in the indirect method, sodium silicate is reacted with salts to first produce a silicate, and then, It is a method of decomposing with mineral acid or carbon dioxide.

The silica obtained by the indirect method has a specific surface area equal to or slightly smaller than that of the silica obtained by the direct method, but has a characteristic that the oil absorption is extremely small. Here, the specific surface area is a numerical value measured by a BET surface area meter, and the oil absorption amount is obtained by kneading powder with boil oil,
It is the maximum amount of oil per unit weight of silica that can maintain the properties as a powder. Since the specific surface area is measured by adsorption of gas, it is a numerical value which is an index of the behavior of thin tube absorption of a fluid having low viscosity and low surface tension like ink. On the other hand, the oil absorption amount is a numerical value that is an index of the behavior of a binder having a relatively high viscosity such as boil oil. Therefore,
Amorphous silica obtained by the indirect method has a lower oil absorption amount than silica obtained by the direct method, and therefore has low absorption in the pores of the binder with high viscosity, and ink absorption is almost the same. There will be.

As a result of intensive investigations by the inventors of the amorphous silica obtained by the indirect method, the amorphous silica obtained by the indirect method was compared with the total amount of inorganic components constituting the ink receiving layer. By containing 15 to 100% by weight,
It has been found that an ink jet recording sheet having a large ink absorption capacity and a strong ink-receiving layer coating strength can be obtained, and the present invention has been completed.

Since the ink receiving layer in the present invention needs to have a function of fixing the solvent of the water-soluble ink,
From the viewpoint of affinity with the solvent of the water-soluble ink, it is preferable to contain a water-soluble binder. Examples of the water-soluble binder that can be used in the present invention include polyvinyl alcohol, vinyl acetate, oxidized starch, esterified starch and ether. Starch, carboxymethyl cellulose, cellulose derivatives such as hydroxyethyl cellulose, casein,
Examples thereof include gelatin and soybean protein.

In the present invention, other binders that can be used in the ink receiving layer include maleic anhydride resins, styrene-butadiene copolymers, methyl methacrylate-butadiene copolymers, and other conjugated diene copolymer latexes. Acrylic polymer latex such as polymers or copolymers of acrylic acid ester and methacrylic acid ester; vinyl polymer latex such as ethylene vinyl acetate copolymer; or functional group such as carboxyl group of these various polymers Functional group-modified polymer latex by containing monomer; Water-based adhesive such as thermosetting synthetic resin system such as melamine resin, urea resin; polymethylmethacrylate, polyurethane resin, unsaturated polyester resin, vinyl chloride-vinyl acetate copolymer, polyvinyl Butyral, Archit Can be mentioned synthetic resin-based adhesive such as a resin.

In the present invention, a cationic dye fixing agent is used for the purpose of increasing the strength of the ink receiving layer containing a water-soluble binder at the time of receiving the water-soluble ink, that is, water resistance, and promoting the fixability of the ink. It is preferable. The cationic dye fixing agent in the present invention uses at least one or more of monomers, oligomers and polymers of primary to tertiary amines or quaternary ammonium salts, which disintegrate when dissolved in water to exhibit cationicity. , Preferably oligomers or polymers.

In the present invention, in the ink receiving layer, a known white pigment other than the amorphous silica obtained by the indirect method is used.
More than one species can be used.

Examples of white pigments include light calcium carbonate, heavy calcium carbonate, kaolin, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide,
Zinc sulfide, zinc carbonate, satin white, aluminum silicate, diatomaceous earth, calcium silicate, magnesium silicate,
Synthetic amorphous silica, colloidal silica, alumina, colloidal alumina, aluminum hydroxide, lithopone, zeolite, hydrohalosite, magnesium carbonate, white inorganic pigments such as magnesium hydroxide, styrene plastic pigment, acrylic plastic pigment, polyethylene, Organic capsules such as microcapsules, urea resins and melamine resins can be mentioned.

In the present invention, the support used is paper or a sheet such as a thermoplastic resin film, a synthetic paper, a synthetic resin laminated paper such as a photographic support, or a non-woven fabric mainly composed of wood fibers or synthetic fibers. Substances. In the case of paper, addition or non-addition of internal sizing agent, use of sizing agents such as neutral sizing agents, polymer sizing agents, and acidic sizing agents alone or in combination, with or without fillers, size press But there are no restrictions.

The internal filler of the paper support is a white pigment,
Conventionally known pigments are used and can be used alone or in combination. For example, light calcium carbonate, heavy calcium carbonate, kaolin, clay, talc, calcium sulfate, barium sulfate, titanium dioxide, zinc oxide, zinc sulfide, zinc carbonate, satin. White, aluminum silicate, diatomaceous earth,
White inorganic pigments such as calcium silicate, magnesium silicate, synthetic silica, aluminum hydroxide, alumina, lithopone, zeolite, magnesium carbonate, magnesium hydroxide, styrene plastic pigments, acrylic plastic pigments, polyethylene, microcapsules, urea resins, Examples include organic pigments such as melamine resins. Furthermore, when the support is paper, it contains a neutral sizing agent and a filler and has a wood pulp / filler ratio of 9
0 to 70% by weight / 10 to 30% by weight and a basis weight of 60
It is preferably 120 g / m ² but not limited thereto.

In the present invention, other additives include
Pigment dispersant, thickener, fluidity improver, defoamer, foam suppressor,
Release agents, foaming agents, penetrants, coloring dyes, coloring pigments, optical brighteners, ultraviolet absorbers, antioxidants, preservatives, antifungal agents,
A water resistance agent, a wet paper strength enhancer, a dry paper strength enhancer and the like can be appropriately blended.

The ink referred to in the present invention means the following colorants,
A recording liquid composed of a liquid medium and other additives. Examples of the colorant include water-soluble dyes such as direct dyes, acid dyes, basic dyes, reactive dyes and food dyes.

The ink jet recording sheet according to the present invention is not limited to use as an ink jet recording sheet, and may be used as any recording sheet using a liquid ink during recording. For example, an ink sheet in which a heat-fusible ink containing a heat-fusible substance, a dye or pigment as a main component is applied on a thin support such as a resin film, high-density paper, or synthetic paper is heated from the back side of the ink sheet to remove the ink. Recording sheet for thermal transfer recording that melts and transfers, inkjet recording sheet that heat-melts a heat-melting ink to form fine droplets and fly recording, inkjet recording sheet using ink in which an oil-soluble dye is dissolved in a solvent, photopolymerization A recording sheet corresponding to a photosensitive pressure-sensitive donor sheet using microcapsules containing a type monomer and colorless or colored dyes and pigments can be used.

[0023]

EXAMPLES Examples of the present invention will be described below, but the present invention is not limited to these examples. Further, "parts" and "%" shown in the examples represent parts by weight and% by weight, unless otherwise specified.

The ink jet recording sheet was evaluated by the following method. 1) Coating layer strength The coating layer strength was measured by sufficiently adhering a cellophane tape having a width of 15 mm to the surface of the ink receiving layer over a length of 50 mm, then peeling it off, and transferring the coating layer component transferred to the adhesive surface of the tape. This was done by observing the amount. The evaluation was carried out by visual observation, and the evaluation was made into 5 levels. The evaluation standard is
5 when no transfer is observed, 4 when a very small amount of coating layer is transferred to the entire surface of the tape, 3 when a small amount of coating layer is transferred to the entire surface of the tape, and 3 when the coating layer is transferred to the entire surface of the tape. Then
It was judged to be 2 when peeling marks were observed on the coating layer side, and 1 when a considerable amount of the coating layer was transferred to the entire surface of the tape and peeling marks were noticeably observed on the coating layer side. The lower limit level is 3 which does not cause any problem in printing or conveyance by a printer.

2) Ink Absorbency The ink absorptivity was measured in the superposed portion where the ink amount per unit area is large and the absorptivity of the ink receiving layer is required. The evaluation was performed using a Canon (BJC-600J) ink jet printer, which was a blue color that is a heavy color of cyan and magenta.
A boundary line of 100% solid part of green which is a solid color of 00% and cyan and yellow, a boundary line of 100% solid part of red which is a heavy color of yellow and magenta and 10 of blue
The boundary line of 0% solid part was observed and the degree of bleeding was observed. The evaluation criteria were set to 3 levels, 3 was judged to have no bleeding at all, 2 was judged to be permissible but slightly bleeding was judged, and 1 was judged to be markedly observed.

Example 1 A high-quality paper having a basis weight of 80 g / m ² was used as a base paper, and a coating solution having the following composition was prepared. The coating solution was adjusted to 9 g / m ² by using an air knife coating device. Was applied as an ink receiving layer and subjected to supercalendering to prepare an inkjet recording sheet. <Ink receiving layer coating liquid> Indirect method amorphous silica (Tokushiru GU, manufactured by Tokuyama Corporation) 100 parts Polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) 17 parts Cationic dye fixing agent (Smilase Resin 1001, Sumitomo Chemical Co., Ltd.) Made) 23 parts

Example 2 An ink jet recording sheet was produced in the same manner as in Example 1 except that the composition of the coating liquid for the ink receiving layer was changed as follows. <Ink receiving layer coating liquid> Indirect method amorphous silica (Tokushiru GU, manufactured by Tokuyama) 50 parts Direct method amorphous silica (Fineseal X-37B manufactured by Tokuyama) 50 parts Polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) ) 17 parts Cationic dye fixing agent (Sumires Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 23 parts

Example 3 An ink jet recording sheet was prepared in the same manner as in Example 1 except that the composition of the coating liquid for the ink receiving layer was changed as follows. <Ink receiving layer coating liquid> Indirect method amorphous silica (Tokushiru GU, manufactured by Tokuyama) 17 parts Direct method amorphous silica (Fineseal X-37B manufactured by Tokuyama) 83 parts Polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) ) 17 parts Cationic dye fixing agent (Sumires Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 23 parts

Comparative Example 1 An ink jet recording sheet was produced in the same manner as in Example 1 except that the composition of the coating liquid for the ink receiving layer was changed as follows. <Ink receiving layer coating liquid> Indirect method amorphous silica (Tokushiru GU, manufactured by Tokuyama) 12 parts Direct method amorphous silica (Fineseal X-37B manufactured by Tokuyama) 88 parts Polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) ) 17 parts Cationic dye fixing agent (Sumires Resin 1001, manufactured by Sumitomo Chemical Co., Ltd.) 23 parts

Comparative Example 2 An ink jet recording sheet was prepared in the same manner as in Example 1 except that the composition of the coating liquid for the ink receiving layer was changed as follows. <Ink-receiving layer coating liquid> Direct-method amorphous silica (Fineseal X-37B, manufactured by Tokuyama Corporation) 100 parts Polyvinyl alcohol (PVA117, manufactured by Kuraray Co., Ltd.) 17 parts Cationic dye fixing agent (Smilase Resin 1001, Sumitomo Chemical Co., Ltd.) 23 parts

[0031]

[Table 1]

As shown in Table 1 above, the ink jet recording sheets of the examples were coated by containing amorphous silica obtained by the indirect method in an amount of 15 to 100% by weight based on the total amount of inorganic components in the ink receiving layer. The layer strength and absorbency were satisfactory. On the other hand, the ink jet recording sheet of Comparative Example was unsatisfactory as an ink jet recording sheet in terms of coating layer strength when the content ratio of amorphous silica obtained by the indirect method was less than 15.

[0033]

According to the present invention, an ink jet recording sheet having a high coating layer strength and a high ink absorbency can be obtained.

Claims (1)

[Claims] 1. An inkjet recording sheet comprising at least one or more ink receiving layers on both sides or one side of a support, wherein amorphous silica is added by an indirect method to the total amount of inorganic components constituting the ink receiving layers. 15 to 100% by weight of the inkjet recording sheet.