JPH07323657A - Inkjet recording sheet - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide an ink jet recording sheet having excellent ink absorbency and clearness of recording, excellent water resistance and durability, and having a good cloth-like texture. [Structure] An ink receiving layer coated on a substrate is an aqueous mixture containing a white pigment and an adhesive resin as main components,
It is characterized in that it is formed by applying a foamed coating material to the base material by introducing air by mechanical stirring.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based ink recording material. More specifically, it has excellent ink absorbency and image quality, high water resistance and durability, and is excellent in flexibility and cloth shape. The present invention relates to an inkjet recording sheet having a good texture.

[0002]

2. Description of the Related Art With the widespread use of ink jet recording systems using water-based inks, not only conventional applications such as output of documents in offices, but also recently expanded applications to POS systems and the like. . In addition, with the rapid improvement in performance of both printers and recording sheets, the printing speed and resolution have improved remarkably, and as the market demand for colorization has increased in recent years, it is easy to support wide color recording. Therefore, the application is rapidly expanding. For the recording sheet, increase the ink absorption speed,
A coating type recording sheet with an ink-receptive coating layer on the surface of the substrate has been developed in order to obtain excellent recording quality with high resolution by increasing the ink receiving amount and improving the uniformity of the dot shape. .

For example, Japanese Patent Application Laid-Open No. 62-158084 discloses a method for producing an ink jet recording sheet having high ink absorbency, color reproducibility and recording density using fine particle synthetic silica as an ink receiving layer. There is. That is, in order to comply with the above-mentioned required characteristics, a method is usually carried out in which a coating layer containing a white pigment having excellent absorbability such as fine particle synthetic silica as a main component is provided on the surface of a base paper containing cellulose pulp as a main component. Has been done. However, when a sheet containing cellulose pulp as a main component is used as the base material, the sheet strength is weak, so not only is it easily broken at the time of handling, but also because it has no water resistance, it is particularly strong when wet with water. The decrease was remarkable, and it sometimes caused problems such as wrinkles, curls, and lumps. For this reason, there is a problem that it cannot be used for applications requiring high strength and is not suitable for outdoor use.

Therefore, in JP-A-64-36478, a film containing a polyolefin resin as a main component is used as a base material,
An inkjet recording sheet having a hydrophobic ink receiving layer formed thereon and having excellent water resistance is disclosed. However, although such a recording sheet is excellent in water resistance, since the base material itself does not have ink absorbability, in order to prevent lateral spreading of the ink during recording and prevent bleeding of dots, There is a problem that not only the ink receiving layer needs to be thick, but also the sheet is hard and lacks flexibility.

On the other hand, as an attempt to produce a flexible ink jet recording sheet, Japanese Patent Laid-Open No. 6366/1986 discloses a method of using a cloth as a base material.
In this case, compared to paper or the like having a flat base material surface, since the fabric surface has a three-dimensional structure and a structure with many voids, a sufficient recording density cannot be obtained by an ordinary recording method, The image also has no depth. For this reason, the amount of ink used for recording is increased within a range where bleeding does not occur. However, such a method not only requires a large amount of expensive ink, but also has a large amount of ink, which reduces the drying property of the ink, and further
The cloth used is also limited to one that can absorb the water-based ink. Further, since the surface of the base material is highly uneven and uneven, even if the amount of ink is increased, the sharpness of the recording and the uniformity of the image become extremely insufficient.

As a means for solving this problem, Japanese Patent Application Laid-Open No. Sho 61-61
No. 138785 and Japanese Patent Publication No. 5-29555 disclose a method of providing an ink receiving layer on a cloth. That is, Japanese Patent Application Laid-Open No. 61-138785 discloses a method of providing an ink receiving layer having a thickness of 0.5 to 30 μm on a cloth, but when the paint is applied on the cloth, the paint is applied to the cloth. It penetrates and becomes a state in which the paint is impregnated into the cloth, and it is difficult to effectively provide the coating layer on the surface of the coating layer. For this reason
Japanese Patent Application Laid-Open No. 5-29555 discloses a method of forming an ink receiving layer on a fabric having a weaving yarn thickness of 200 μm or less and a weaving gap of 200 μm or less as a base material for the purpose of preventing penetration of a paint. . When this method is used, since the ink receiving layer is present separately from the cloth, the ink is excellent in drying property, water resistance,
It is possible to produce a durable recording sheet.

However, when the coating material is directly applied to such a cloth, the cloth itself is porous as compared with paper or film even if a specific cloth as defined in the claims of the patent is used, The paint penetrates into the fabric and becomes an impregnated state. Therefore, the recording layer cannot be provided only on the surface of the fabric, and the uniformity of the surface of the recording layer is insufficient, so that a good recorded image cannot be obtained. On the other hand, before coating the recording layer, a method of coating an emulsion such as styrene-butadiene copolymer as a barrier layer is also shown, but when coating a coating such as emulsion on a porous cloth,
Since the cloth is impregnated with the paint, not only must a large amount of paint be applied to impart barrier properties, but the paint impregnated into the cloth impairs the soft texture of the cloth itself. There was a problem that Furthermore, since the barrier layer cannot effectively cover the surface of the fabric, even if an ink receiving layer is provided on the fabric surface, a large amount of ink receiving layer paint must be applied to obtain good recording. There was a problem.

Further, Japanese Patent Publication No. 63-56876 discloses a recording material having a porous resin layer as a recording liquid receiving layer. In this method, the porous resin layer is formed by kneading or dispersing water- or acid-soluble inorganic particles in the resin and then leaching the inorganic particles by immersing the particles in water or acid, or by applying heat or heat. A material that foams by light is kneaded in a resin and then formed into a film, and then pores are formed in the resin by heating or light irradiation.

However, in the former method, the amount of inorganic particles that can be blended with the resin is limited, not only is the porosity in the coating film limited, but there are many inorganic particles that are not eluted because they are surrounded by the resin. Since it is highly possible that the particles are present and it is difficult to uniformly mix the particles, the quality variation of the obtained sheet becomes large, and a clear recorded image cannot be obtained. Further, after mixing the inorganic particles with the resin to form a film, elution treatment with water or acid is further required, which causes a problem that the manufacturing process becomes extremely complicated.

On the other hand, in the case of using a method in which a substance which is foamed by heat or light is mixed in a resin and the film is foamed,
In order to obtain the ink absorbing layer, it is necessary to mix a substance that decomposes with heat or light to generate a gas in the resin, and not only is mixing and handling with the resin complicated,
The gas generated by decomposition must escape from the film layer, so the usable resin is limited to resins with low strength at room temperature, that is, resins not suitable for practical use, or thermoplastic resins whose strength decreases when heated. In addition to the large manufacturing restrictions and complicated manufacturing method, the pores that are formed are extremely uneven, so stable production of good quality sheets that can withstand inkjet recording is required. Had the problem of being difficult.

[0011]

The object of the present invention is not only to have strong sheet strength such as tensile strength and tear strength, excellent water resistance and durability, but also to have a supple and flexible cloth-like texture, It is an object of the present invention to provide an inkjet recording sheet capable of high-speed printing of a high-quality image having excellent ink absorbability and good dot reproducibility when recording with an inkjet printer or plotter using ink. .

[0012]

Means for Solving the Problems As a means for solving the above problems, the present inventors have previously provided a foamed coating material as an undercoat layer on a spunbonded nonwoven fabric, and on top of this undercoat layer, a pigment and an aqueous system are provided. An inkjet recording sheet provided with an ink receiving layer made of an adhesive has been developed, and an application has already been filed as a patent. This recording sheet has excellent recording quality, water resistance, durability and flexibility.

In the process of completing the present invention, the present inventors have come to realize that the foam coating layer formed on the nonwoven fabric as the barrier layer has a high ink absorbing performance, and further the foaming layer has an ink receiving performance. Even if a base material that is extremely porous and easily penetrates the paint by the usual method is used by adding a white pigment, the ink does not penetrate to the back surface of the base material, and the ink has good sheet surface property and ink. They have found that an inkjet recording sheet having receptivity, good dot reproducibility, and excellent sheet strength, water resistance, and durability can be obtained, and completed the present invention.

The recording sheet of the present invention has an extremely low-density and flexible foam coating directly applied to the substrate, and the flexible and good texture of the nonwoven fabric or cloth used as the substrate is almost impaired. Never. That is, in the ink jet recording sheet according to the present invention, a sheet-like support and an aqueous coating material containing a white pigment and an adhesive resin as main components provided on the support are mechanically stirred to foam. And an ink receiving layer formed by applying a foam paint.

As the support used in the present invention, spunbonded non-woven fabric, dry non-woven fabric formed by card method, spunlace non-woven fabric, wet non-woven fabric, air-laid non-woven fabric, woven fabric and the like can be used, but it is cloth-like. In terms of texture,
Spunbond nonwoven fabric, dry nonwoven fabric, spunlace nonwoven fabric, and woven fabric are preferable.

The spunbonded non-woven fabric used in the present invention is a web in which continuous filaments of thermoplastic resin are accumulated in a sheet form, and has self-bonding areas at regular intervals. Such a non-woven fabric has both flexibility and strength because the continuous filaments are formed by the regions where the continuous filaments are self-fused and the regions where they are not self-fused. The material of the continuous filament is not particularly limited,
Examples thereof include polyolefin resin, polyester resin, polyamide resin, polyacrylic acid ester resin and the like. The fineness of the continuous filament is in the range of 1 to 10 denier, preferably in the range of 1 to 7 denier. When the fineness is less than 1 denier, it becomes difficult to stably produce a long fiber sheet, and when the fineness exceeds 10 denier, the fiber becomes thick and the flexibility of the sheet decreases, which is not preferable.

The regular self-bonding area of the spunbonded nonwoven fabric is formed by introducing the continuous filaments accumulated on the support between a heated uneven roll and a smooth roll, and applying heat and pressure treatment to obtain unevenness. It is formed by fusing the sheet portion corresponding to the convex portion of the roll. It is also possible to form a point fusion-bonded portion corresponding to the convex portion by introducing the accumulated continuous filaments between the concave-convex roll and the ultrasonic horn and performing ultrasonic treatment. The unit weight of the spunbonded nonwoven fabric usable in the present invention is 20 to 150 g / m ² ,
It is preferably 30 to 120 g / m ² . When the basis weight is less than 20 g / m ² , not only the opacity and handling property of the sheet are insufficient, but also the foam-coated paint may strike through at the portion where the accumulation of fibers is small, which is not preferable. On the contrary,
If it exceeds 150 g / m ² , the flexibility of the sheet decreases, which is not suitable.

The dry non-woven fabric usable in the present invention is a sheet produced by defibrating staple fibers with a card machine and then adhering the fibers with heat or an adhesive. The agent or the like is applied to the sheet. The fibers forming the dry nonwoven fabric used in the present invention are not particularly limited, and examples thereof include polyolefin fibers, polyester fibers, polyamide fibers, rayon, and cotton. It is possible to use one kind or a mixture of two or more kinds.

The fiber length of the staple fibers is preferably 20 to 200 mm, most preferably 30 to 150 mm. If the staple fiber length is less than 20 mm, the strength and flexibility of the sheet prepared by the card method are insufficient, and conversely, if the fiber length exceeds 200 mm, it is difficult to defibrate the fiber by the card method, which is good. You can't get a formation sheet.
The dry fabric used in the present invention has a basis weight of 20 to 150 g / m ² , preferably 30 to 120 g / m ² . When the basis weight is less than 20 g / m ² , the opacity and handleability of the sheet are insufficient, which is not preferable, and when the basis weight exceeds 150 g / m ² , the flexibility of the sheet decreases, which is not suitable.

The spunlaced nonwoven fabric that can be used in the present invention is not particularly limited. For example, after staple fibers are defibrated by a card machine, high pressure water column flow treatment is performed on the defibrated staple fibers. A sheet in which staple fibers are entangled with each other can be used. In this case, as the staple fibers, the same fibers as those used in the dry non-woven fabric can be used, and the basis weight is preferably ²⁰ to 150 g / m ² as in the dry non-woven fabric. Further, after stacking a short fiber sheet prepared in advance and a long fiber sheet made of continuous filaments, short fibers constituting the short fiber sheet and long fibers constituting the long fiber sheet by subjecting the short fiber sheet surface to high-pressure water column flow A spunlace nonwoven fabric produced by entanglement and integration of and can be used as a substrate. Also in this case, the basis weight of the spunlaced nonwoven fabric is preferably ²⁰ to 150 g / m ² for the same reason as that of the dry nonwoven fabric.

The short fiber sheet is usually produced by a wet papermaking method. As the short fiber, in addition to non-wood pulp such as wood pulp, hemp pulp, linter and straw, a range of 1 to 20 mm, preferably 2 to 15 mm is used. Mention may be made of synthetic fibers and binder fibers cut to a range of lengths. When the cut fiber length is shorter than 1 mm, the entanglement with long fibers becomes insufficient when the high pressure water column flow treatment is applied, and conversely the fiber length becomes shorter.
When it is longer than 20 mm, it is difficult to produce a short fiber sheet having a good texture by a wet method, which is not preferable.

The continuous fiber sheet made of continuous filaments is not particularly limited, but spunbonded nonwoven fabric can be used, for example. The above-mentioned spunbonded non-woven fabric can be used as the spun-bonded non-woven fabric, but the basis weight is 5 to 5 in order to effectively entangle with short fibers.
It is preferably in the range of 40 g / m ² . If the basis weight of the spunbonded non-woven fabric is less than 5 g / m ² , the strength of the long fiber sheet decreases, and therefore the strength of the sheet after being entangled with the short fibers decreases, which is not suitable. On the other hand, when the basis weight exceeds 40 g / m ² , when the high pressure water column flow treatment is applied, it becomes difficult for the high pressure water column flow to pass through the spunbonded nonwoven fabric, resulting in the entanglement of long fibers and short fibers constituting the spunbonded nonwoven fabric. Is not suitable because it will be blocked.

The cloth used in the present invention is produced by weaving warp threads and weft threads. For example, cloth made of fibers such as cotton, rayon, polyester, polyamide, polyacryl and the like can be used. The basis weight of the fabric used in the present invention is 20 to 150 g / m ² for the same reason as in the case of the dry non-woven fabric.
It is preferably in the range of.

In the present invention, a foamed ink receiving layer is provided on the above substrate. As the adhesive resin used in the ink receiving layer, conventionally known adhesive resins can be used, and examples thereof include polyacrylic acid ester, polymethacrylic acid ester, ethylene-vinyl acetate copolymer, polyvinyl acetate, styrene-butadiene rubber ( SBR), nitrile-butadiene rubber (NBR), methyl methacrylate-
In addition to aqueous emulsions of butadiene rubber (MBR), polyester resins, polyurethane resins, alkyd resins, etc., emulsions of these copolymers can also be used. Further, those obtained by introducing a functional group such as a carboxyl group or a cationic group into these polymers can also be used, and a polyacrylamide resin, a polyvinyl acetal resin, etc. can also be used. Furthermore, starch, starch derivatives, polyvinyl alcohol, modified polyvinyl alcohol, casein,
Water-soluble polymers such as cellulose derivatives can also be used.
These adhesive resins may be used alone or in admixture of two or more, if necessary.

A white pigment is blended in the ink receiving layer.
As the white pigment, amorphous silica, zeolite, calcium carbonate, calcium silicate, aluminum hydroxide, calcined clay, kaolin clay, talc, titanium dioxide, white carbon, organic pigment (plastic pigment) and the like can be used. Among these white pigments, amorphous silica has a particularly high ink absorbing property and is effective as a pigment for the ink receiving layer. Most preferably, the amorphous silica mainly contains a component having a secondary particle diameter of 1 to 10 μm.
The blending ratio of the polymer material in the ink receiving layer is preferably in the range of 10 to 100% by weight based on the total solids of the ink receiving layer. If the proportion of the polymer material is less than 10%, the adhesive strength of the ink receiving layer becomes insufficient, which is not preferable.

A foam stabilizer is optionally added to the ink receiving layer coating material for the purpose of improving the foamability of the coating material and the stability of the foamed coating material. Examples of the foam stabilizer include higher fatty acids, modified higher fatty acids, alkali salts of higher fatty acids, and the like. The amount of foam stabilizer added is 10
It is 0 to 30 parts by weight, preferably 1 to 15 parts by weight per 0 parts by weight, and if the amount added exceeds 30 parts by weight, the stability of the coating composition is lowered, which is not preferable.

The aqueous mixture containing a white pigment and an aqueous polymer as a main component is foamed before coating. Foaming is accomplished by mechanically stirring the mixture and entraining air. Actually, it may be foamed using a conventionally known foaming machine, for example, a continuous foaming machine such as a continuous foaming machine manufactured by Gaston County, Inc. of the United States, a continuous foaming machine manufactured by Stokes of the Netherlands, a shaking mixer, A cake mixer or the like can also be used. Foaming ratio of paint (ratio of paint volume after foaming to paint volume before foaming comparing with paint of constant weight) is
It is preferably in the range of 2.5 to 20 times, preferably in the range of 2.5 to 10 times. When the expansion ratio is smaller than 2.5 times, the foaming of the paint is not sufficient and the penetration into the porous substrate cannot be prevented, which is not preferable. On the other hand, if the expansion ratio exceeds 20 times, the foam interface of the foamed paint will become extremely thin,
Since the bubbles are easily broken, it is not preferable because it is difficult to obtain a uniform coated surface and the stability of the foam coating itself is lowered.

The viscosity of the foamed paint is 3,000 to 20 as measured by a B-type viscometer (using a # 4 rotor, measured at 12 rpm).
It is preferably in the range of 0,000 cp, preferably in the range of 5,000 to 100,000 cp. If the viscosity of the paint is less than 3,000 cp, it is not preferable because the paint easily penetrates into the base material even if the expansion ratio is appropriate, and if it exceeds 200,000 cp, the viscosity of the paint is too high and the coatability is high. Is not preferable because it becomes defective.

Means for applying the foamed coating material include
Known coating means such as Mayer bar, slit die, lip, comma, roll, and rotary screen can be used. The coating amount of foamed paint is 3-30g / m ²
It is preferably 5 to 25 g / m ² . If the coating amount is less than 5 g / m ² , the ink absorption is insufficient, and if it exceeds 30 g / m ² ,
Since the coating amount is large, the cost becomes expensive, which is not preferable. If necessary, auxiliary agents such as a lubricant, an antifungal agent, an antistatic agent, a fluorescent dye, and an organic colored pigment may be appropriately added to the coating material.

If desired, the coated sheet can be smoothed on its coated surface by using a means such as a super calender or a machine calender. The linear pressure when calendering is 70 kg / cm or less, preferably 50 kg / cm or less. When the linear pressure exceeds 70 kg / cm, the density of the sheet becomes high and the texture is deteriorated, which is not preferable. It is also possible to use a heated calendar for smoothing, and in this case, as compared with the case of not heating,
The base material can be smoothed with a low linear pressure.

[0031]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the following examples, all parts and% are parts by weight and% by weight.

Example 1 A spunbonded non-woven fabric was prepared in which continuous polyethylene terephthalate filaments were integrated and softening or melting of the polyethylene terephthalate filaments had a point fusion area where filaments were fixed to each other. The filaments constituting this spunbonded nonwoven fabric had a fineness of 2.3 denier and a basis weight of 40 g / m ² .
Next, fine particle silicic acid (made by Tokuyama soda, fine seal) 10
Polyvinyl alcohol (made by Kuraray, product number 117
, 10% aqueous solution) was mixed with a hand mixer to foam the paint. The paint has a foaming ratio of 3.5 times and a viscosity of 11,000 measured with a B-type viscometer.
It was cp. This foamed coating is applied to the surface of the spunbonded non-woven fabric prepared above so that the coating amount after drying becomes 10 g / m ² by using a Meyer bar to form an ink receiving layer, and ink jet recording is performed. A sheet was prepared.

Example 2 A spunbonded non-woven fabric having polyethylene terephthalate continuous filaments integrated therein and having a point-fused area in which the filaments are fixed by softening or melting of the polyethylene terephthalate filaments was prepared. The filaments constituting this spunbonded nonwoven fabric had a fineness of 2.3 denier and a basis weight of 60 g / m ² .
Next, fine particle silicic acid (made by Tokuyama soda, fine seal) 10
For 0 parts, 300 parts silanolated polyvinyl alcohol (Kuraray, product number R-1130, 10% aqueous solution), 5 parts polyethyleneimine quaternary ammonium salt and foam stabilizer (Dainippon Ink, product number F-1, solid content 33) %) 6 parts, and then stirred using a hand mixer to foam the paint. The foaming ratio of this paint was 4.0, and the viscosity measured by a B-type viscometer was 18,000 cp. This foam coating is applied to the surface of the spunbonded non-woven fabric prepared above so that the coating amount after drying will be 15 g / m ² using an applicator bar to form an ink receiving layer for inkjet recording. A sheet was prepared.

Example 3 A spunbonded non-woven fabric having polyethylene terephthalate continuous filaments integrated therein and having a point fusion zone in which the filaments are fixed to each other is prepared by softening or melting the polyethylene terephthalate filaments. The filaments constituting this spunbonded nonwoven fabric had a fineness of 5.2 denier and a basis weight of 110 g / m ² .
Next, fine particle silicic acid (made by Tokuyama soda, fine seal) 10
80 parts of styrene-butadiene copolymer latex (manufactured by Japan Synthetic Rubber, product number 0619, solid content 48%) and polyvinyl alcohol (manufactured by Kuraray, product number NL05, 15% aqueous solution) per 0 part
60 parts and foam stabilizer (Kanebo NSC, product number YC80C,
The paint containing 6 parts of solid content 35%) was stirred using a hand mixer to foam the paint. The foaming ratio of this paint is 10
And the viscosity measured by a B-type viscometer was 90,000 cp. This foam coating is applied to the surface of the spunbonded non-woven fabric prepared above so that the coating amount after drying will be 20 g / m ² using an applicator bar to form an ink receiving layer, for inkjet recording. A sheet was prepared.

Example 4 A spunbonded non-woven fabric having polyethylene terephthalate continuous filaments accumulated therein and having a point fusion zone where filaments are fixed by softening or melting of the polyethylene terephthalate filaments was prepared. The fineness of the filaments constituting this spunbonded nonwoven fabric was 1.7 denier, and the basis weight was 50 g / m ² .
Next, fine particle silicic acid (made by Tokuyama soda, fine seal) 10
Hand paint with 0 parts of polyurethane emulsion (Dainippon Ink, product number HW940, solid content 50%) 50 parts and foam stabilizer (Dainippon Ink, product number F-1, solid content 33%) 6 parts The paint was foamed by stirring with a mixer. The foaming ratio of this paint was 5.2, and the viscosity measured by a B-type viscometer was 38,000 cp. This foam paint,
An ink receiving layer was formed by coating the surface of the previously prepared spunbonded nonwoven fabric with a Meyer bar so that the coating amount after drying was 8 g / m ² , to form an ink jet recording sheet.

Example 5 A spunbonded non-woven fabric was prepared in which polypropylene continuous filaments were accumulated, and the polypropylene filaments were softened or melted to have point fusion areas where filaments were fixed to each other. The filaments constituting this spunbonded nonwoven fabric had a fineness of 3 denier and a basis weight of 60 g / m ² . Next, 50 parts of fine particle silicic acid (made by Tokuyama soda, fine seal), 50 parts of calcium carbonate (made by Shiraishi Industry, product number Brilliant 15) and 70 parts of acrylic emulsion (made by Japan Synthetic Rubber, product number AE513A, solid content 44%) were prepared. Foaming agent (Dainippon Ink, product number F-1, solid content 33%) 6
The paint in which the parts were mixed was stirred using a hand mixer to foam the paint. The foaming ratio of this paint was 4.8 and the viscosity measured by a B-type viscometer was 19,000 cp. This foamed coating is applied to the surface of the spunbonded non-woven fabric prepared above using a Meyer bar so that the coating amount after drying is 15 g / m ² to form an ink receiving layer, which is used for inkjet recording. A sheet was prepared.

Example 6 A spunbonded non-woven fabric having polyethylene terephthalate continuous filaments accumulated therein and having a point fusion zone where filaments are fixed to each other is prepared by softening or melting the polyethylene terephthalate filaments. The filaments constituting this spunbonded nonwoven fabric had a fineness of 2.3 denier and a basis weight of 50 g / m ² .
Next, kaolin clay (Engelhard, part number UW-90) 10
Acrylic emulsion (made by Japan Synthetic Rubber,
A paint containing 60 parts of product number AE513A, solid content 44%) and 5 parts of a foam stabilizer (manufactured by Dainippon Ink, product number F-1, solid content 33%) was stirred using a hand mixer to foam the paint. . The foaming ratio of this paint was 6.0, and the viscosity measured by a B-type viscometer was 42,000 cp. This foam coating is applied to the surface of the spunbonded non-woven fabric prepared above so that the coating amount after drying will be 20 g / m ² using an applicator bar to form an ink receiving layer, for inkjet recording. A sheet was prepared.

Example 7 As a base material, a dry non-woven fabric having a basis weight of 50 g / m ² (made by Fukuron,
The procedure of Example 2 was repeated except that the product number C-00155) was used to obtain an inkjet recording sheet.

Example 8 An ink jet recording sheet was obtained by repeating the procedure of Example 2 except that a spunlace nonwoven fabric having a basis weight of 80 g / m ² (manufactured by Shin Oji Paper Co., Ltd., product number Texel P80Z) was used as the substrate. .

Example 9 An ink jet recording sheet was obtained by repeating the procedure of Example 2 except that a polyester woven fabric having a basis weight of 50 g / m ² was used as the base material. Example 10 The sheet produced in Example 2 was further smoothed with a super calendar. The line pressure of the super calendar is 50kg
It was / cm.

Comparative Example 1 The procedure of Example 1 was repeated except that the paint was not foamed. The paint penetrated into the non-woven fabric, passed through to the back surface, and became an impregnated state, which significantly increased the coating amount. Comparative Example 2 The operation of Example 7 was repeated except that the paint was not foamed. The paint penetrated into the non-woven fabric, passed through to the back surface, and became impregnated, resulting in a significant increase in the coating amount. Comparative Example 3 The operation of Example 8 was repeated except that the paint was not foamed. The paint penetrated into the non-woven fabric, passed through to the back surface, and became impregnated, resulting in a significant increase in the coating amount.

Comparative Example 4 The foaming ratio of the paint was doubled, and the viscosity measured by a B type viscometer was
The procedure of Example 1 was repeated except that the foam paint adjusted to 3,000 cp was used. Although coating was performed using a Mayer bar, the coating material penetrated to the back surface of the base material and became impregnated in the base material, resulting in a large increase in the coating amount. Comparative Example 5 An ink jet recording sheet was prepared by repeating the same procedure as in Example 1 except that a base material was 80 g / m ² of high-quality paper (manufactured by Shin Oji Paper Co., Ltd., Sunflower) and the paint was not foamed. Obtained.

Comparative Example 6 An ink jet recording sheet was obtained by repeating the procedure of Example 1 except that the coating amount was 2.5 g / m ² . Comparative Example 7 Synthetic paper as a base material (made by Oji Yuka Synthetic Paper, trade name YUPO FPG60)
Was used and the same operation as in Example 4 was repeated except that the paint was not foamed to obtain an ink jet recording sheet.
The sheets obtained in Examples 1 to 10 and Comparative Examples 1 to 7 were tested by the following test methods to evaluate their quality. The results are shown in Table 1.
As shown in.

Test Method (1) Strikethrough of Paint: The degree of penetration of the paint into the substrate (the degree of strikethrough) when the paint was applied to the substrate was visually evaluated. The evaluation was carried out in the following five stages. 5 ... Penetration of the paint is slight, and there is no strike-through of the paint. 4 ... The paint penetrates to the middle of the substrate, but there is no strike-through of the paint. 3 ... The paint penetrates into the base material considerably, but there is almost no strike-through of the paint. 2 ... Paint penetrates to the back side and strike-through occurs. 1 ... The paint is completely penetrated and the base material is in an impregnated state.

(2) Sheet surface property: The surface property of the sheet when the coating material was applied to the substrate was visually evaluated. The evaluation was carried out in the following five stages. 5 ... A coating layer is formed on the surface of the substrate, and the surface property is extremely good. 4 ... A coating layer is formed on the surface of the substrate, and the surface property is good. 3 ... The surface properties of the sheet are normal. 2. The surface of the sheet is poor because the surface of the sheet is hardly covered with paint. 1 ... The surface of the sheet was not completely covered with the paint, and the surface properties of the sheet were extremely poor.

(3) Ink absorbency: An ink jet printer (manufactured by HP, DESK WRITER-C) was used to measure the time taken for the printed ink to dry. The evaluation was carried out in the following five stages. 5 ... Less than 4 seconds 4 ... 4 to 6 seconds 3 ... 7 to 10 seconds 2 ... 11 to 15 seconds 1 ... 16 seconds or more

(4) Vividness of recording: Using an ink jet printer (manufactured by HP, DESK WRITER-C), the recorded portions of yellow, magenta and cyan were visually evaluated. The evaluation was carried out in the following five stages. 5 ... The color of the recorded portion is extremely clear. 4 ... The color of the recorded portion is clear. 3 ... The color of the recorded area is normal. 2 ... The color of the recorded part is sunk. 1 ... The color of the recorded portion is sunk and is extremely unclear.

(5) Tear strength: Measured according to JIS P 8116. (6) Water resistance: The test sheet was immersed in water for 1 minute, then torn by hand, and compared with a sheet not immersed in water. The evaluation was carried out in the following 5 stages. 5 ... No strength reduction is observed even when immersed in water. 4 ... Almost no decrease in strength is observed even when immersed in water. 3 ... Even when soaked in water, the strength is usually reduced. 2 ... When immersed in water, the strength is slightly reduced. 1 ... When immersed in water, the strength is significantly reduced.

[0049]

[Table 1] As is clear from Table 1, when the ink jet recording sheets obtained in Examples 1 to 10 and the sheets obtained in Comparative Examples 1 to 7 are compared, the sheets obtained in Examples 1 to 10 are foamed. Since the coating material is applied to the base material, the coating material effectively covers the surface of the base material, and the foam coating layer has good ink absorption performance, and therefore has excellent inkjet recording suitability. On the other hand, the sheets obtained in Comparative Examples 1 to 3 did not foam the coating material, and the sheets obtained in Comparative Example 4 had a low expansion ratio and viscosity of the coating material. Not only causes the coating material to escape to the back of the base material and causes coating troubles, but also because the coating material cannot effectively cover the surface of the base material, the uniformity of the sheet surface is poor and the recording quality is poor. Furthermore, since the base material is impregnated with the coating material, the coating amount increases and the texture of the sheet also deteriorates.

On the other hand, the sheet obtained in Comparative Example 5 was extremely inferior in water resistance because the base material was paper, and the sheet obtained in Comparative Example 6 had a small coating amount, and thus was not coated with a paint. The material surface cannot be covered sufficiently, the uniformity of the sheet surface is insufficient, and the ink absorbency is also insufficient, so that clear recording cannot be obtained. In addition, the sheet obtained in Comparative Example 7 has good water resistance but weak tear strength because the base material is a synthetic paper, and since the coating material is used without foaming, the base material itself does not have ink absorbability. In addition, the ink absorption of the sheet is insufficient at the coating amount of 8 g / m ² .

[0051]

As described above, in the ink jet recording sheet according to the present invention, the ink receiving layer coated on the substrate comprises a foam layer containing a white pigment and an aqueous polymer as main components. , Has excellent ink absorbency and sharpness of recorded image. Further, by using a non-woven fabric or a woven fabric as the base material, it has high tear strength and tensile strength, excellent water resistance, and a soft cloth-like texture.

Claims (6)

[Claims] 1. A base material and an ink receiving layer formed on one surface of the base material. The ink receiving layer mechanically comprises an aqueous mixture containing a white pigment and an adhesive resin as main components. An ink jet recording sheet, which is an ink receiving layer formed by applying a foaming paint, which is agitated and entrained with air to foam, onto a substrate. 2. The ink jet recording sheet according to claim 1, wherein the substrate is one selected from a non-woven fabric and a woven fabric. 3. The foaming ratio of the paint forming the foamed layer (ratio of the volume after foaming and the volume before foaming, as compared with a paint having a constant weight) is in the range of 2.5 to 20 times, and the B-type viscosity is 3. The ink jet recording sheet according to claim 1, wherein the paint viscosity after foaming measured by a meter is in the range of 3,000 to 200,000 cp. 4. A coating material forming a foam layer comprises a higher fatty acid,
4. An alkali salt of a higher fatty acid, or one or more kinds selected from a modified product of a higher fatty acid, characterized in that
The inkjet recording sheet described above. 5. The coating material for forming the foamed layer contains amorphous silica as a white pigment and an adhesive resin having a cationic group or a carboxyl group as an adhesive resin. 5. The inkjet recording sheet according to any one of 3 and 4. 6. A non-woven fabric comprising a base material in which a large number of continuous filaments are accumulated, a dry non-woven fabric produced by defibrating staple fibers by a card machine, and a spunlace non-woven fabric produced by entanglement of fibers by a high pressure water column flow. A non-woven fabric selected from the group consisting of:
6. The inkjet recording sheet according to any one of 4 and 5.