JPH11291616A - Ink jet recording sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain curls from being caused by environments and obtain a high glossiness by providing an ink receptive layer containing ink-absorptive resin on one surface of a sheet-like support coated with polyolefin resin in both surfaces of an original paper, and providing a back layer containing cellulostic resin on the other surface thereof. SOLUTION: The sheet-like support comprises an original paper and a polyolefin resin-coated layer covering both surfaces thereof. An ink-receptive layer provided on one surface of the support is composed by adding ink- absorptive resin as main component and a pigment and various other kinds of additives as ancillary material. A back layer to be provided on the other surface of the support is formed by employing cellulostic resin having a curl- suppressive effect hardly causing sticking troubles when being superimposed on the ink receptive layer. Then, an adhesive modifier such as hydrophobic resin may be added to the back layer in order to improve adhesiveness to the polyolefin resin-coated layer of a sheet-like base material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet for ink jet recording, and more particularly to a sheet for ink jet recording having little gloss change due to environment and high gloss.

[0002]

2. Description of the Related Art Ink-jet recording is a method in which small droplets of ink are caused to fly from nozzles by various methods, and recording is performed by adsorbing and absorbing ink droplets on a recording sheet. This method has features such as low noise, high-speed recording, and compatibility with colorization, and is used in various applications. In recent years, with the advancement of the performance of personal computers and the spread of multimedia, there has been an increasing demand for printing documents including colors and full-color images at offices and homes. There is a demand for an ink jet recording sheet that can perform printing output at a high speed, can obtain a high-definition printed image with less bleeding and good dot reproduction, and can obtain gloss comparable to that of conventional silver halide photography.

[0003] Conventionally, as an ink jet recording sheet, an ink-absorbing resin or an ink-receiving layer composed of various pigments, water-soluble resins, various latexes, etc. is provided on one surface of a paper base, and if necessary, a super calender treatment is performed. For example, a sheet having a smooth surface is used.
However, such an inkjet recording sheet has a problem that high gloss cannot be obtained because the flatness of the paper substrate is poor, or the ink droplets absorb ink droplets during printing and swell to produce irregularities. was there. In order to compensate for the drawbacks of the paper substrate, various plastic sheets such as polyester films, or resin-coated paper in which both sides of base paper are coated with polyethylene resin are used as sheet-like supports. A problem occurred.

[0004] Ink-jet recording sheets are desired to satisfy certain curl conditions in terms of appearance and paper feeding and running in a printer. Usually, it is necessary to be flat or convex (called back curl) with the ink receiving layer facing upward in the environment of use. That is, when the ink jet recording sheet is viewed as a printed matter, if the curl that is placed in a concave shape with the ink receiving layer surface facing upward (referred to as a top curl), the edge of the printed matter when held in the hand is Lift up and look bad. Alternatively, when the printed matter is attached to a wall or the like for use, there is an inconvenience that the edge is separated from the wall surface, so that the printed matter cannot be attached properly. Or,
When printing with a printer, if the ink jet recording sheet has a top curl, it hinders the feeding of the recording sheet and causes a problem that printing cannot be performed normally.
Therefore, the ink jet recording sheet is preferably flat or has a slightly convex curl.

However, since the ink receiving layer has the property of expanding and contracting due to changes in the temperature and humidity of the environment, even if a desired curl is obtained in a specific environment, a large top curl may be exhibited in a low temperature and low humidity environment. In a high-temperature, low-humidity environment, on the contrary, a problem such as a back curl tends to occur. In order to suppress the curl, if the thickness of the sheet-like support used is increased to increase the rigidity, it can be suppressed to some extent, but the completed ink jet recording sheet is thick and impractical, or the cost increases. There were inconveniences such as. Various attempts have been made to maintain the desired curl properties as described below. However, at present, an ink jet recording sheet having both high gloss and curl properties has not been realized.

In Japanese Patent Application Laid-Open No. Hei 8-269900, paper having natural pulp as a main component is used as a substrate, and one side of the paper substrate on which an image forming layer is provided is coated with a resin (A) having film forming ability. An image forming support, which is used by being wound into a roll having the opposite side of the paper substrate coated with a polyolefin resin, wherein the side on which the image forming layer of the image forming support is provided is externally wound; It discloses a support for an image material characterized by being stored at a temperature of at least ℃. However, simply storing a sheet-like support coated with a polyolefin resin at a specific temperature and making it curl,
Even in a certain environment, even if a desired curl is obtained, it is difficult to suppress the curl generated by a change in the use environment.

JP-A-6-171206 discloses an ink-jet recording sheet having at least one or more ink-receiving layers on the surface of a support and at least one or more backcoat layers on the back surface. Discloses an ink-jet recording sheet comprising a pigment and a binder as main components, and having an average equilibrium water content of the pigment of 1.9 to 5.5%. As the support, wood pulp such as chemical pulp, mechanical pulp, waste paper pulp and the like, and base paper manufactured using a conventionally known pigment as a main component, coated paper provided with a polyolefin resin layer on base paper, and various films are used. The back layer is composed of a pigment and a binder, for example, light calcium carbonate, heavy calcium carbonate, kaolin, various pigments such as talc, and as a binder, polyvinyl alcohol, vinyl acetate, oxidized starch, etherified starch, carboxymethyl methylcellulose And various binders such as cellulose derivatives such as hydroxyethyl cellulose.

However, the back layer containing a pigment and a binder as main components has a disadvantage in that the curl suppressing effect is small and it is necessary to make the coating film excessively thick in order to obtain a sufficient effect. In JP-A-6-171207, at least one ink-receiving layer is provided on the surface of a support mainly composed of wood pulp and pigment, and at least one backcoat layer is provided on the back surface of the support. The binder for the back coat layer has a glass transition temperature of −50 to + 25 ° C.
Synthetic polymer latex as an essential component, starch,
There is disclosed an ink jet recording sheet comprising a mixture of at least one water-soluble binder composed of polyvinyl alcohol and a cellulose derivative. As the support, wood pulp such as chemical pulp, mechanical pulp or waste paper pulp, and base paper produced using a conventionally known pigment as a main component are used. However, this method has disadvantages such as insufficient suppression of curl, and high gloss suitable for printing a full-color image cannot be obtained due to unevenness of a paper substrate or unevenness caused by ink absorption. .

Japanese Patent Application Laid-Open No. 5-286228 discloses a recording sheet having a dye-adsorbing layer provided on a substrate, and a swellable polymer layer provided on the opposite side of the surface of the substrate on which the dye-adsorbing layer is provided. A provided recording sheet is disclosed. As a substrate,
Polyester resin such as polyethylene terephthalate, polyester diacetate, polycarbonate resin,
Various plastic sheets such as fluorinated resins such as ETFF are used. Examples of the material of the swellable polymer layer include polyvinyl alcohol, polyvinylpyrrolidone, and a blend thereof. However, polyvinyl alcohol, polyvinylpyrrolidone, and the like have a problem that they tend to cause blocking because they exhibit adhesiveness when absorbing moisture.

JP-A-5-96843 discloses a recording sheet including an ink receiving layer, a base sheet, a heat absorbing layer, and an anti-curl layer. As a base sheet, a transparent base material such as polyester, polycarbonate, polysulfone, cellulose triacetate, polyvinyl chloride, cellophane, polyvinyl fluoride, a base sheet,
Flat paper or opaque plastic is used. As the anti-curl layer, hydroxypropylmethylcellulose, hydroxybutylmethylcellulose, hydroxyethylmethylcellulose, hydroxyethylcellulose,
Hydroxyethylcellulose, salts of carboxymethylcellulose, salts of carboxymethylhydroxyethylcellulose, methylcellulose and the like are used. However, even with this method using a cellulosic resin, the cost is increased due to the necessity of a heat absorbing layer, or curling is suppressed in a low humidity environment, but curling is insufficient in a high humidity environment. There were inconveniences such as

[0011]

SUMMARY OF THE INVENTION The present invention provides an ink jet recording sheet which solves the above problems, suppresses curling due to the environment, and has a high gloss.

[0012]

As a result of repeated studies, the present inventors have found that a sheet-like support comprising a base paper, a polyolefin resin coating layer coated on both sides thereof, and a sheet-like support provided on one side of the support. It has been found that the above problems can be solved by an ink-jet recording sheet comprising an ink-receiving layer mainly composed of an ink-absorbing resin and a back layer mainly composed of a cellulose-based resin provided on the other surface of the support. The present invention has been completed. The present invention includes the following aspects. [1] A base paper, a sheet-like support composed of a polyolefin resin coating layer coated on both surfaces thereof, an ink-receiving layer containing an ink-absorbing resin provided on one surface of the support, An ink jet recording sheet having a back layer containing a cellulose resin provided on the other surface. [2] The ink jet recording sheet according to [1], wherein the back layer contains an adhesion improver having an affinity for the polyolefin resin. [3] The ink jet recording sheet according to [1] or [2], wherein the adhesion improver contains at least one selected from a polyolefin resin, a polyester resin, and an ethylene-vinyl acetate copolymer. [4] Cellulose resin is cellulose nitrate, cellulose acetate, cellulose acetate-pyropionate, cellulose acetate-butyrate, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylhydroxyethylcellulose [1], [2] or [3], wherein the sheet comprises at least one selected from the group consisting of carboxymethylhydroxyethylcellulose salt and carboxymethylcellulose salt.

[5] The ink jet recording sheet according to any one of the above, wherein the polyolefin resin is polyethylene. [6] The ink jet recording sheet according to any one of the above, wherein the polyolefin resin coating layer on the front side (the side on which the ink receiving layer is provided) of the sheet-like support contains titanium dioxide as a white pigment. [7] The ink jet recording sheet according to any one of the above, wherein an undercoat layer is provided between the polyolefin layer and the ink receiving layer or between the polyolefin layer and the back layer. [8] The inkjet recording sheet according to [4], wherein the cellulose resin contains at least one selected from carboxymethylcellulose, carboxymethylcellulose salts, hydroxypropylmethylcellulose, and hydroxyethylcellulose.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The sheet-like support of the present invention is
And a polyolefin resin coating layer coated on both sides.
You. The thickness of the base paper is not particularly limited, but is 30 μm to 500 μm.
μm is preferred. Ink thinner than 30μm
Jet recording sheet has low rigidity and feels when picked up
Inconvenience such as reduced texture or opacity
May occur, and if it is thicker than 500 μm,
Is difficult to handle, causing trouble in paper feeding with the printer
May cause life. A more preferred range is 50μ
m to 300 μm. There is no particular restriction on the weight of the base paper.
No, but 30g / m^Two~ 500g / m ^TwoThe range of
Is preferred. Base paper is composed mainly of pulp
It is a pulp sheet. As wood pulp, LBKP,
Chemical pulp such as NBKP, GP, PGW, RMP, T
Mechanical pulp such as MP, CTMP, CMP, CGP, D
Various pulp such as waste paper pulp such as IP are exemplified.
Further, if necessary, various conventionally known papermaking additives may be added.
It can also be blended. Various papermaking additives include
Pigment for paper (filler), binder, sizing agent, fixing agent, step
Retention improver, cationizing agent, dry paper strength agent, wet paper
Force enhancer, pH adjuster, conductive agent, dye, etc. are exemplified,
One or more of these materials may be blended.
it can. As a paper machine, there are known fourdrinier paper machines and cylindrical paper machines.
Machine, twin wire paper machine, etc. can be used. Also acid
Papermaking in any of neutral, neutral and alkaline
No.

The base paper can be tab-sized or size-pressed with starch or polyvinyl alcohol, etc., following papermaking. Further, a surface smoothness treatment such as a machine calender, a heat calender, a soft calender, and a super calender can be performed. The polyolefin resin coating layer is formed by melt-coating a base paper with a resin composition containing a polyolefin resin as a main component and, if necessary, a white pigment and various additives. Examples of the polyolefin resin include homopolymers and copolymers of ethylene, propylene and the like, and one or more of these can be used as a mixture. Among them, low-density polyethylene, medium-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene can be exemplified as suitable materials because they have good workability and are easily available. Physical properties such as molecular weight, density, and melt index of the polyolefin resin are not particularly limited, but the molecular weight is preferably 20,000 to 200,000 from the viewpoint of workability and curl suitability. The density is preferably from 0.915 to 0.950 g / m ³ , and the melt index is preferably from 2 to 40 g / 10 min (JIS K-6760). Further, a white pigment and various additives can be blended in the polyolefin resin coating layer. Above all, it is preferable to mix a white pigment in the polyolefin resin coating layer on the front side in order to increase whiteness and opacity.

Examples of the white pigment include anatase type titanium dioxide, rutile type titanium dioxide, zinc oxide, calcium carbonate, talc and the like.
More than one kind can be mixed and used. The blending amount of the white pigment is also not limited, but is 0.1 to 30 parts by weight based on 100 parts by weight of the polyolefin resin. If it is less than 0.1 part by weight, the effect of increasing whiteness and opacity is small, and if it exceeds 30 parts by weight, it becomes difficult to disperse it in an olefin resin. The preferred range is 1 to 15 parts by weight. Examples of the additives include white pigments, colored pigments, dyes, optical brighteners, antioxidants, plasticizers, and dispersants. The mixing of the polyolefin resin with the white pigment and the additives is performed using a kneading extruder, a heating roll kneader, a Banbury mixer, a pressure kneader, or the like.

The polyolefin resin coating layer is melt-extruded.
It is formed by a coating method. That is, on the running base paper
Using a polyolefin resin composition melt extruder,
The film is cast from the slit die and coated.
The temperature of the molten film depends on the type of resin
However, the temperature is generally from 150C to 350C. Slit die
As T-type die, L-type die, Fishtil type die
Or a flat die is preferred, and the opening diameter of the slit is 0.1
It is desirably about 2 mm. In addition, the molten tree on the front side
Mirror finish as a cooling roll to cool the grease film
Cooling rolls with a highly smooth surface such as raised
The use is to reduce the gloss of the inkjet recording sheet.
It is effective to enhance. Also the molten resin film on the back side
The cooling roll to cool is roughened
Preferably, a cooling roll is used. Polio
The coating amount of the refining resin coating layer depends on the front and back
5g / m^Two~ 50g / m^TwoIt is. 5g
/ M^TwoIf the amount is smaller, the adhesion to the base paper is insufficient, and 50 g /
m^TwoBeyond this, the sheet-like support becomes thicker,
Inconveniences such as unnecessarily raising the port occur. preferable
Range is 10 g / m^Two~ 30g / m ^TwoIt is. Also of the base paper
Selection of type and coating amount of polyolefin resin to coat the surface
The choice has an effect on the curl and the difference in polyolefin crystallinity
The resin density of the front and back polyolefins
Do not select or make a difference between the coating amount on the front side and the back side
The curl size can be manipulated to some extent
Noh.

Known materials can be appropriately used for the ink-receiving layer mainly composed of the ink-absorbing resin of the present invention as long as desired printability is obtained. The ink-receiving layer of the present invention is mainly composed of an ink-absorbing resin, a pigment as an auxiliary material,
It is configured by adding various additives. Ink absorbent resin is a resin having the ability to absorb ink ejected when printing with an inkjet printer, for example,
Polyvinyl alcohol, cationized polyvinyl alcohol, modified polyvinyl alcohol such as silanol-modified polyvinyl alcohol, polyvinyl pyrrolidone, modified polyvinyl pyrrolidone, gelatin, modified gelatin, casein,
Examples include various starch derivatives such as soybean casein, modified soybean casein, starch, oxidized starch, etherified starch, and phosphated starch, cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, and hydroxypropylmethylcellulose, and latexes. Can do things. The compounding amount of the ink absorbing resin is preferably at least 70% by weight of the whole ink receiving layer. 7
If the amount is less than 0% by weight, the ink absorbing ability may be insufficient. Alternatively, a pigment is blended for the purpose of compensating for insufficient absorption capacity, and depending on the type and amount of the pigment, the transparency of the ink receiving layer may be reduced, and disadvantages such as high gloss may not be obtained. More preferably, it is at least 85% by weight.

Examples of the pigment for the ink receiving layer include synthetic amorphous silica, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, alumina, kaolin, clay, satin white, diatomaceous earth, calcium sulfate, barium sulfate, and silicate. Examples include calcium, magnesium silicate, titanium dioxide, magnesium hydroxide, synthetic zeolite, zinc oxide, zinc sulfide, zinc carbonate, styrene plastic pigment, acrylic plastic pigment, microcapsules, colloidal silica, and the like. The surface of the ink receiving layer can be roughened to the extent that the gloss is not reduced, and the effect as an antiblocking agent can be obtained. Further, if necessary, water-soluble resins, latex, ink fixing agent, pigment dispersant, thickener, fluidity improver, defoamer, foam inhibitor, release agent, foaming agent, penetrant,
Coloring dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, antioxidants, preservatives, antiseptic agents, water-proofing agents, and the like can also be appropriately compounded. The ink receiving layer of the present invention can be applied by a known method. For example, it can be appropriately selected from various coating methods such as various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, short dwell coaters, gravure coaters, extrusion coaters, and curtain coaters.

The coating amount of the ink receiving layer is determined by the desired printability (for example, ink absorption, ink drying, dye coloring,
There is no limitation as long as the bleeding, print density, sharpness, etc. can be obtained. The preferred range is 3 to 50 g / m ^2. If the amount is too small, the ink absorbency tends to be insufficient, and the printability may be poor. If the amount exceeds 50 g / m ² , the effect of the printability is saturated, the thickness becomes thick, the cost is unnecessarily increased, and it is difficult to suppress curling. Inconveniences such as

The material of the back layer of the present invention is not particularly limited as long as the curl suppressing effect can be obtained. However, a cellulose resin has a high curl suppressing effect. ) Is preferred because of less occurrence. Here, the cellulosic resin is cellulose and various cellulose derivatives. Cellulose derivatives can be exemplified by derivatives obtained by esterifying or etherifying this by utilizing the reaction of a hydroxyl group of a glucose residue which is a constituent unit of cellulose. For example, examples of the cellulose ester include cellulose nitrate, cellulose acetate, cellulose acetate-pyrropionate, and cellulose acetate-butyrate. Examples of the cellulose ether include methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, hydroxypropyl methyl cellulose, and carboxymethyl hydroxyethyl cellulose. Alternatively, salts such as sodium carboxymethyl cellulose may be used.

Among them, sodium carboxymethylcellulose, hydroxypropylmethylcellulose,
Hydroxyethylcellulose can be suitably used because it has a high curl suppressing effect even with a relatively small coating amount and has little fear of blocking. Although the degree of substitution of the cellulose derivative is not particularly limited, the solubility in water changes depending on the degree of substitution. Therefore, when applied as a water-based paint, the degree of substitution is preferably within the range of the degree of substitution having water solubility. For example, in the case of a sodium salt of carboxymethylcellulose, the degree of substitution is preferably 0.4 or more. The degree of polymerization of the cellulosic resin is not particularly limited, but if the degree of polymerization is high, the viscosity of the coating material becomes excessively high. Usually, the polymerization degree is preferably in the range of 50 to 5000.

As the cellulose resin of the present invention, the above-mentioned various celluloses can be used alone or in combination of two or more. For the purpose of improving the adhesion between the backing layer and the polyolefin resin coating layer of the sheet-like substrate, an adhesion improver such as a hydrophobic resin can be added. Examples of the adhesion improver include a resin having a hydrophobic portion having a good affinity for a polyolefin resin, such as a polyolefin-based resin dispersion, a polyester-based resin dispersion, or an ethylene-vinyl acetate copolymer emulsion. Mitsui Petrochemical Industries, Ltd.
Trademark: Chemipearl (for example, Chemipearl S-100, S-120, SA-10)
0, V-100, etc.). As a polyester resin dispersion, commercially available from Takamatsu Yushi Co., Ltd.
Trademarks: Pesresin (for example, Pesresin A-510, Pesresin A-515G, Pesresin A-513E, Pesresin NT-3, etc.). As the ethylene-vinyl acetate copolymer resin, a trade name of Aquatex (for example, Aquatex HA1100, Aquatex MC3800, commercially available from Chuo Rika Kogyo Co., Ltd.)
Aquatex MC4400). The amount of the adhesion improver is not particularly limited, but is preferably 0.5 to 30 parts by weight based on 100 parts by weight of the cellulose resin. If the amount is too small, the effect of improving the adhesion is not sufficiently exhibited, and if it is too large, the curl suppressing effect may be impaired.

Various pigments can be blended for the purpose of adjusting the frictional resistance of the back layer, imparting writability, or preventing blocking. Pigments include synthetic amorphous silica, light calcium carbonate, heavy calcium carbonate, magnesium carbonate, alumina, kaolin, clay, satin white, diatomaceous earth, calcium sulfate, barium sulfate, calcium silicate, magnesium silicate, titanium dioxide, and hydroxide. Examples thereof include magnesium, synthetic zeolite, zinc oxide, zinc sulfide, zinc carbonate, styrene-based plastic pigment, acrylic-based plastic pigment, microcapsules, and colloidal silica. The amount of the pigment varies depending on the size and shape of the pigment to be used, the type of the cellulose resin, and the coating amount of the back layer, but is generally less than 50% by weight of the entire back layer. If the amount of the pigment is excessive, the curl suppression effect is diminished.
Preferably it is less than 10% by weight. Further, the back layer of the present invention, if necessary, a surfactant, a pigment dispersant,
Thickeners, flow improvers, defoamers, defoamers, mold release agents, foaming agents, penetrants, coloring dyes, coloring pigments, fluorescent brighteners, ultraviolet absorbers, antioxidants, preservatives, antifouling A soaking agent, a water-proofing agent and the like can be appropriately compounded.

The back layer of the present invention can be coated by a known method. For example, various blade coaters, roll coaters, air knife coaters, bar coaters, rod blade coaters, short dwell coaters, gravure coaters, extrusion coaters,
It can be appropriately selected from various coating methods such as a curtain coater. The coating amount of the back layer is preferably in the range of 3 to 50 g / m ² . If the amount is too small, the curl suppressing effect is not exhibited, and if the amount is too large, the back curl becomes excessive, or the back curl becomes excessive, or the cost becomes unnecessarily increased, which causes inconvenience. The ink receiving layer and the back layer of the present invention,
Although it can be applied directly on the sheet-like substrate, it can be subjected to a surface activation treatment such as corona discharge treatment or flame treatment for the purpose of improving the adhesion to the sheet-like substrate, or an undercoat layer. Can also be provided.

The composition of the undercoat layer is not particularly limited as long as the adhesion between the ink receiving layer and the back layer and the sheet-like substrate is improved, but various water-soluble resins, various latexes, various pigments, various additives, Can be exemplified. For example, polyvinyl alcohol, cationic polyvinyl alcohol, modified polyvinyl alcohol such as silanol-modified polyvinyl alcohol, polyvinyl pyrrolidone, modified polyvinyl pyrrolidone, gelatin, modified gelatin, casein, soy casein, modified soy casein, starch, oxidized starch, etherified starch, phosphorus Various starch derivatives such as acid esterified starch, carboxymethyl cellulose,
Examples thereof include cellulose derivatives such as hydroxyethylcellulose, methylcellulose, and hydroxypropylmethylcellulose, and various latexes as main components, to which various pigments and various additives are added in small amounts.

The glossiness of the ink receiving layer is preferably 50 or more, more preferably 70% or more, and most preferably 85% or more.

[0028]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should be understood that the present invention is by no means restricted thereto. Example 1 Production of base paper Softwood bleached kraft pulp (NBKP, Canadian Standard Freeness (JIS P-8121) 250 m)
l) and hardwood bleached kraft pulp (LBKP, Canadian Standard Freeness 280 ml) in a weight ratio of 2:
The mixture was mixed at a ratio of 8 to prepare a pulp slurry having a concentration of 0.5%. The following papermaking additives are added to this pulp slurry,
The following addition amount was blended with the absolute dry weight of the pulp, and the mixture was sufficiently stirred and dispersed. The pH is adjusted to 7.5 by adding 2.0% of cationized starch, 0.4% of alkyl ketene dimer, 0.1% of anionized polyacrylamide resin, 0.7% of polyamide polyamine epichlorohydrin resin and aqueous sodium hydroxide solution. .

The pulp slurry having the above composition is paper-made by a fourdrinier machine, passed through a drier, a size press, and a machine calender, and has a basis weight of 180 g / m ² , a strength of 1.0 g / cm ³ ,
A pulp paper having a moisture content of 7.5% was produced and used as a base paper.
The composition of the size press liquid is as follows. 2 parts by weight of carboxyl-modified polyvinyl alcohol and 1 part by weight of sodium chloride. Adjust the concentration of size press liquid to 5%,
This liquid was applied to both sides of the paper such that the liquid application amount was 25 g / m ² .

Coating of Polyolefin Resin Coating Layer After applying corona discharge treatment to both front and back surfaces of the base paper, the following polyolefin resin coating layer composition 1 mixed and dispersed by a Banbury mixer is applied to the wire side of the base paper. The working amount was 30 g / m ² (the back surface, the surface on which the back layer of the ink jet recording sheet was provided), and the coating amount of the polyolefin resin composition 2 was 30 g on the felt side.
/ M ² (surface, surface of the ink jet recording sheet on which the ink receiving layer is provided), and applied by a melt extruder having a T-type die (melting temperature: 280 ° C.).

Polyolefin resin coating layer 1 65 parts by weight of high density polyethylene resin (density 0.945, melt index 20 g / 10 min), 35 parts by weight of low density polyethylene resin (density 0.914, melt index 4 g / 10 min).

Polyolefin resin composition 2 35 parts by weight of a linear low density polyethylene resin (density 0.926, melt index 20 g / 10 min) and 50 parts by weight of a low density polyethylene resin (density 0.919, melt index 2 g / 10 min) , 10 parts by weight of anatase type titanium dioxide (trade name: A-220, manufactured by Ishihara Sangyo), 0.1 parts by weight of zinc stearate, antioxidant (trade name: Irganox 1010, manufactured by Ciba Geigy)
0.03 parts by weight, ultramarine (Daiichi Kasei, trademark: Aoguchi ultramarine N
o. 2000) 0.09 parts by weight, and 0.3 parts by weight of a fluorescent whitening agent (trade name: UVITEX OB, manufactured by Ciba Geigy). In the laminate coating on the front side, a cooling roll having a mirror-finished chrome plating was used.

Coating of Back Layer After the surface of the polyolefin resin coating layer on the back side (wire side) was subjected to a surface activation treatment by corona treatment, the back layer composition 1 having the following composition was applied in an amount of 20 g / g. m
Coating was performed so as to be ² . Back layer composition 1 90 parts by weight of hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., trade name: Metroose 60SH-15), 10 parts by weight of ethylene-vinyl acetate copolymer resin (manufactured by Chuo Rika Kogyo Co., Ltd., trade name: Aquatex MC4400), interface Activator (manufactured by NOF Corporation, trademark: Nonion MN811) 0.1
Parts by weight, silica (Mizukasil P, manufactured by Mizusawa Chemical Industry Co., Ltd.)
-526) 1 part by weight.

Coating of Ink Receiving Layer Next, the surface of the polyolefin resin coating layer on the front side (felt surface side) is subjected to a surface activation treatment by corona treatment, and then the ink receiving layer composition 1 having the following composition is applied. Is 20
g / m ² and coated with a bar coater. Ink receiving layer composition 1 polyvinyl alcohol (Kuraray Co., Ltd., Kuraray Povar 11)
7) 95 parts by weight, 3 parts by weight of a cationic resin (Sumitomo Chemical Co., Sumireze Resin 1001) as an ink fixing agent, and a water resistant agent (Sumitomo Chemical Co., Sumitex Resin M)
-3) 2 parts by weight of synthetic amorphous silica (manufactured by Mizusawa Chemical Industries,
Mizukasil P78D) 0.5 parts by weight.

Example 2 Production of base paper A base paper was produced in the same manner as in Example 1 except that the basis weight was changed to 105 g / m ² . Coating of polyolefin resin coating layer Coating amount on the front side is 15 g / m ² , and coating amount on the back side is 15 g / m ²
A polyolefin resin coating layer was provided in the same manner as in Example 1 except that the thickness was changed to m ² . Coating of Back Layer A back layer composition 2 having the following composition was applied so that the coating amount was 15 g / m ² . Back layer composition 2 carboxymethyl cellulose (Daiichi Kogyo Seiyaku, trademark:
95 parts by weight of cellogen 7A), 5 parts by weight of a polyester resin dispersion (trade name: Pesresin A-513E, manufactured by Takamatsu Yushi), 0.05 part by weight of surfactant (manufactured by Dainippon Ink and Chemicals, trademark: Megafac F116) .

Coating of ink receiving layer The ink receiving layer composition 2 having the following composition was coated at a coating amount of 15 g / m 2.
Coating was performed so as to be ² . Ink receiving layer composition 2 polyvinylpyrrolidone (trade name: K-90, manufactured by BASF)
80 parts by weight, 20 parts by weight of polyvinyl alcohol (manufactured by Kuraray, Kuraray Poval 117), and cationic resin (Sumitomo Chemical Resin 100, manufactured by Sumitomo Chemical Co., Ltd.) as an ink fixing agent
1) 10 parts by weight, 5 parts by weight of a water-resistant agent (Sumitomo Chemical Co., Ltd., Sumitex Resin M-3).

Example 3 Production of base paper A base paper was produced in the same manner as in Example 1 except that the basis weight was 75 g / m ² . Coating of polyolefin resin coating layer Coating amount on the front side is 10 g / m ² , and coating amount on the back side is 10 g / m ²
A polyolefin resin coating layer was provided in the same manner as in Example 1 except that the thickness was changed to m ² . Coating of undercoat layer Prior to coating of the back layer, after applying a corona treatment to the polyolefin resin coating layer in order to enhance the adhesion between the polyolefin resin coating layer and the back layer, an undercoat layer composition having the following composition 1 was applied such that the coating amount was 0.5 g / m ² . Undercoat layer composition 1 50 parts by weight of styrene-butadiene copolymer latex (manufactured by Nippon Synthetic Rubber, trademark: 0561) and 50 parts by weight of silica (manufactured by Mizusawa Chemical Industries, trademark: Mizukasil P50). Coating of Back Layer A back layer composition 3 having the following composition was applied so that the coating amount was 10 g / m ² . Back layer composition 3 hydroxyethyl cellulose (trade name, manufactured by Fuji Chemical Co., Ltd.)
AL-15F) 80 parts by weight, polyolefin-based resin dispersion (manufactured by Mitsui Petrochemical Industries, trade name: Chemipearl S-10)
0) 20 parts by weight. Coating of ink receiving layer The ink receiving layer was coated in the same manner as in Example 2.

Example 4 An ink jet recording sheet was completed in the same manner as in Example 2 except that the back layer had the following composition. Back layer composition 5 carboxymethylcellulose (Daiichi Kogyo Seiyaku, trademark:
Cellogen 7A) 50 parts by weight, silica (manufactured by Mizusawa Chemical Industries,
Trademark: Mizukasil P-526) 45 parts by weight, polyester resin dispersion (manufactured by Takamatsu Yushi, trademark: Pesresin A-5)
13E) 5 parts by weight, and 0.05 parts by weight of a surfactant (manufactured by Dainippon Ink and Chemicals, trademark: Megafac F116).

Comparative Example 1 An ink jet recording sheet was completed in the same manner as in Example 1 except that the back layer had the following composition. The coating amount is 20 g / m ² . Back layer composition 4 polyvinyl alcohol (Kuraray, Kuraray Povar 42)
0) 100 parts by weight

Comparative Example 2 An ink jet recording sheet was completed in the same manner as in Example 1 except that the polyolefin resin coating layers on the front side and the back side were not provided. [Evaluation] The ink jet recording sheets of the respective examples and comparative examples produced in the above steps were evaluated by the following methods. (1) Curl The finished ink jet recording sheet is cut into A4 size sheets, placed on a flat table, and placed in the following environment for 5 minutes each.
After adjusting the humidity for 4 hours, measure the lifting height of the four corners and measure
The average of the corners was calculated to be a curl. The convex shape with the receiving layer surface facing upward is called a back curl, and the concave shape is called a top curl. Environment: normal temperature and normal humidity 20 ° C 60% RH, low temperature and low humidity 10 ° C
30% RH, high temperature / humidity 30 ° C., 80% RH Curl needs to be flat or a back curl within an appropriate range in any environment. Specifically, it is preferable that the average value of the curl height by the above method is in the range of 0 to -50 mm (-indicates back curl). Above all, if it is in the range of 0 to -10 mm, it can be used favorably without any inconvenience when printing or viewing with a printer.
A back curl larger than -50 mm does not hinder printing, but makes it difficult to lift and flatten the central portion of the printed matter during viewing. Alternatively, inconveniences such as the sheet becoming a cylinder occur. On the other hand, if the average value of the curl heights is positive, the edge of the sheet is lifted up, and the printing head of the printer comes into contact with the print head at the time of printing, causing a problem that printing is not performed normally.

(2) Gloss The gloss (75-degree gloss) of the surface of the receiving layer of the completed ink jet recording sheet was measured according to JIS-P8142. For an ink jet recording sheet for printing full color, 85% or more is preferable, and 90% or more is particularly excellent. Table 1 shows the measurement results.

[0042]

[Table 1]

As can be seen from Table 1, the curl of the ink jet recording sheet of the present invention does not become top curl even in a low humidity environment or a high humidity environment as well as in a normal temperature and normal humidity environment. Height is 0m
m to −20 mm, which was a good range. In addition, the glossiness showed an excellent value of 90% or more, and a good inkjet recording sheet for printing a full-color image was obtained (Examples 1 to 4). Example 4 exhibited a flat curl (0 mm) at a low temperature and a low humidity. This is presumably because the back layer composition contained a large amount of pigment, so that the curl suppressing effect was weaker than the other examples. On the other hand, when polyvinyl alcohol was used for the back layer, the curl suppressing effect was insufficient, and in a low humidity environment, the curl became 30 mm in the top curl, which caused inconvenience in paper feed running during printing (Comparative Example). 1). Alternatively, when the polyolefin resin coating layer was not provided, the curl height was relatively small at 10 mm, but was top curl, the gloss was as low as 40%, and was poor (Comparative Example 2).

[0044]

As described above, an ink jet recording sheet is prepared by forming a sheet-like support comprising a base paper and a polyolefin resin coating layer coated on both sides thereof, and an ink receiving layer provided on one surface of the support. And a back layer made of a cellulose resin provided on the other surface of the support, not only in a normal temperature and normal humidity environment, but also in a low humidity environment or a high humidity environment, which causes a practical problem. Thus, an ink jet recording sheet having both a high back curl height in a range without gloss and a high glossiness was achieved. The present invention does not become top curl even if the environment changes,
Therefore, the effect is obtained that the edge is not lifted up at the time of appreciation, or the printer does not run inconveniently at the time of printing, and a highly glossy inkjet recording sheet can be obtained.

Claims (4)

[Claims] 1. A sheet-like support comprising a base paper, a polyolefin resin coating layer coated on both sides thereof, an ink-receiving layer containing an ink-absorbing resin provided on one side of the support, An ink jet recording sheet having a back layer containing a cellulose-based resin provided on the other surface of the body. 2. The ink jet recording sheet according to claim 1, wherein the back layer contains an adhesion improver having an affinity for the polyolefin resin. 3. The ink jet recording sheet according to claim 1, wherein the adhesion improving agent contains at least one selected from a polyolefin resin, a polyester resin, and an ethylene-vinyl acetate copolymer. 4. The method according to claim 1, wherein the cellulose resin is cellulose nitrate,
Cellulose acetate, cellulose acetate-pyropionate, cellulose acetate-butyrate, methylcellulose, ethylcellulose, hydroxymethylcellulose, hydroxyethylcellulose, carboxymethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, carboxymethylhydroxyethylcellulose, carboxymethylhydroxyethylcellulose salt, and carboxymethylcellulose salt The inkjet recording sheet according to claim 1, wherein the sheet comprises at least one member selected from the group consisting of: