JPS63162272A - Recording sheet for ink jet printing - Google Patents

Abstract

PURPOSE:To obtain a recording sheet for ink jet printing with superior absorp tive properties and sharpness of a recording image by adding a denatured polyvi nyl alcohol (PVA) having a nonionic substitution group which contains a sulfonic group in an absorptive layer. CONSTITUTION:A denatured PVA a nonionic substitution group which contains a sulfonic group is added to an ink absorptive layer of a recording sheet for ink jet printing which contains the absorptive layer in a support layer base and/or its surface. The denatured PVA having the nonionic substitution group which contains the sulfonic group can be obtained by saponification of a copoly mer consisting of a monomer of vinylester and the nonionic substitution group which contains the sulfonic group. As a monomer composed of the nonionic substitution group which contains the sulfonic group, for instance, vinylmethy lsulfone, vinyldimethylsulfonamide, etc., are used. In addition, when a copolymer consisting of a monomer having the nonionic substitution group which contains the sulfonic group and vinylester is applied, a small quantity of a monomer having either and amino group or an ammonium base may be employed.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to an inkjet recording sheet, and more particularly to an inkjet recording sheet that has excellent ink absorbency and excellent clarity of recorded images.

B. Conventional technology The inkjet recording method is being applied to facsimiles, various printers, etc. because of its low noise, ease of colorization, and high-speed recording. Conventionally, ordinary paper has been used as the recording material used in the inkjenit recording method. but,
As the performance of inkjet recording machines improves, such as faster recording and multicolor recording, more advanced properties are required of inkjet recording sheets. That is, the first
The first is that the ink absorption speed is high, the second is that the diameter of the ink dot is not larger than necessary, and the third is that the shape of the ink dot is close to a perfect circle.

In order to meet these requirements, various studies are underway, such as using polyvinyl alcohol, polyacrylamide, polyvinylpyrrolidone, etc., as ink-absorbing materials, but the current situation is that they are far from meeting the requirements at a practical level. It is.

C0 Problems to be Solved by the Present Invention The purpose of the present invention is to provide an inkjet recording sheet that satisfies the above-mentioned requirements and particularly improves ink absorbency and clarity of recorded images. be.

Yet another object of the present invention is to
Provides an inkjet recording sheet with excellent transparency that can be used for observation by projecting a recorded image onto a screen IJ-n or the like using an optical device such as a PC, or for observation of transmitted light on a color display, etc. It's about doing.

Means for Solving the D0 Problems The present invention We have solved the above problems and made intensive studies to achieve the above objects, and as a result, we have developed an ink jet recording having an ink absorbing layer in and/or on the surface of the supporting substrate. An inkjet recording sheet characterized in that the absorption layer contains modified polyvinyl alcohol (hereinafter polyvinyl alcohol is abbreviated as PVA) having a nonionic substituent containing a sulfone group is characterized in that the absorption layer contains modified polyvinyl alcohol (hereinafter polyvinyl alcohol is abbreviated as PVA). The present invention was completed based on the discovery that the present invention is an inkjet recording sheet with excellent clarity of recorded images.

The modified 1'VA having a sulfonic group-containing nonionic substituent used in the present invention generally saponifies a copolymer of a vinyl ester and a monomer having a sulfonic group-containing nonionic 11tM group. You can get it by doing this.

The vinyl ester used in this method includes vinyl acetate, vinyl propionate, and vinyl formate, with vinyl acetate being preferred from an economic standpoint.

Furthermore, examples of the monomer having a nonionic substituent containing a threadone group used in this method include vinylmethylsulfone, vinyldimethylsulfonamide, and the like.

In addition, when carrying out the copolymerization of the above-mentioned monomer having a 7-ionic substituent containing a sulfonic group and vinyl ester, other copolymerizable monomers such as Eva, ethylene, Propylene, styrene, alkyl vinyl ether, vinyl versatate, (methane acrylic acid, maleic anhydride, crotonic acid, itaconic acid, fumaric acid and other unsaturated acids and their alkyl esters, alkali salts, trimethyl-3-(1-(meth) ) acrylamide-1,1-dimethylbrobyrnammonium chloride, trimethyl-3
-(]-(meth)acrylamido-1,1-dimethylethyl)ammonium chloride, trimethyl-3-(1
-(meth)acrylamidopropyl)ammonium coulide, N-vinylimitazole, N-vinyl-N-methylimidazole, and monomers having an amide group or an ammonium base such as quaternized products of these t'15. They can also be used together in small amounts.

The content of the sulfonic group-containing nonionic substituent in the modified PVA used in the present invention is 0.1 to 50 mol%, preferably 0.1 to 50 mol%, preferably 0.1 to 20 mol% as a sulfonic group-containing 7-ionic monomer unit. %, preferably 1 to 1O
Selected from the range of mol%.

The degree of saponification of the vinyl ester unit may be within a water-bathable range (usually from 50 to 100 mol%, preferably from 60 to 0 mol%).

Further, the degree of polymerization of the modified PVA is not particularly limited, but is usually selected from the range of so to 3oou, preferably 100 to 2500.

The modified PVA used in the present invention can be used alone or in combination with other water-soluble or water-dispersible resins. Other water-bathable or water-dispersible resins that can be used in combination include albumin, gelatin, casein,
Starch, cationized starch, gum arabic, cellulose derivatives such as methylcellulose, hydroxyethylcellulose, polyamide resin, melamine resin, nonionic water-soluble resins such as PVA, poly(meth)acrylamide, polyvinylpyrrolidone, C-C, poly(meth) Anionic water bath resins such as sodium acrylate, anion-modified 1'Vum, sodium alginate, water-soluble polyester,
Polyethyleneimine, polyvinylamine, polyallylamine, polyallylamine 7;
Cationic water bath resins such as cationic polyamide resins,
Examples include water-dispersible resins such as 8BB latex, NBI (latex), vinyl acetate emulsion, ethylene/hinyl acetate copolymer emulsion, methane acrylic ester emulsion, and vinyl chloride emulsion.

When these water-soluble or water-dispersible resins are used in combination with the modified 1'VA used in the present invention, the combined ratio is preferably 100 parts by weight or less based on 0 parts by weight of the modified PVA IU of the present invention. 50 parts by weight or less (for historical use only).

In addition, the modified PVA used in the present invention is silica,
It can also be used in combination with fillers such as clay, talc, diatomaceous earth, zeolite, calcium carbonate, alumina, zinc oxide, and satin white. In this case, the combined ratio differs depending on the recording sheet with excellent transparency and other cases, but usually [the modified PVA/filler of the present invention] has a weight ratio of i/lo0 to l IJ (1/1, Preferably, it is selected from the range of 5/lo o to 10()15.

As the supporting substrate used in the present invention, any conventionally known transparent or opaque supporting substrate can be used.

Transparent support substrates include, for example, polyester, polystyrene, polyvinyl chloride, polymethyl methacrylate,
Examples include films and sheets of cellulose acetate, polycarbonate, polyimide, cellophane, celluloid, and transparent flat paper.

Examples of the opaque support substrate include general paper, pigment-coated paper, cloth, wood, metal plates, synthetic paper, and synthetic resin films or sheets that have been opaquely treated.

In the case of an inkjet recording sheet with excellent transparency, which is one of the objects of the present invention, a transparent support substrate is not used.
T, Ru.

In the present invention, a modified L'VA having a sulfonic group-containing nonionic substituent in and/or on the surface of the supporting substrate
As a method for forming an ink absorbing layer containing
A size press, an air knife coater, a p-ru coater 1. It can be impregnated into the supporting substrate using a conventional coating method such as a bar coater or blade coater, or a coating layer can be formed on the upper surface or both the upper and lower surfaces of the supporting substrate.

Furthermore, when the supporting substrate is paper, a method of internally adding the above-mentioned water bath liquid or aqueous dispersion during paper making can also be used.

The above-mentioned modified PV in the inkjet recording sheet of the present invention
There is no particular restriction on the content of A, but it is usually 0.1 to 2.
00η, preferably 1 to I U Og/lri.

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited thereby. In the examples, "%" and "part J" represent weight basis unless otherwise specified.

The methods for measuring various physical properties in Examples are shown below.

(1) Inkjet recording method Color inkjet recording was performed using the following four colors of ink using a recording apparatus having an on-demand inkjet recording head with an ejection orifice diameter of 60 μm, and the recording characteristics were evaluated.

Yellow ink (composition) C0, acid yellow: i-2, 32 parts diethylene glycol 30 parts water
70 parts magenta ink (composition) a, i, acid red 32 2 parts diethylene glycol 30 parts water
70 parts Cyan ink (composition) U, I, Direct Blue 86 2 parts diethylene glycol 30 parts water
70 copies black ink (
Composition) (3,1, Direct Black 19 2 evil diethylene glycol, 30 parts water
70 copies (2) Ink absorption speed After inkjet recording, the print on the recording sheet was rubbed with a finger at regular intervals, and the time until the printed area remained unchanged was measured.The shorter the time, the faster the ink absorption speed. It's large.

(3) Bleeding degree The diameter of the printed dot was measured using a stereomicroscope, and the diameter was shown to indicate how many times larger it was than the ink droplet. The lower the magnification, the less blurring.

(4) Transparency The visible light transmittance (%) of the non-printed portion of the inkjet recording sheet was measured using a spectrophotometer using visible light with a wavelength of 500 nm. This transmittance is defined as transparency. The larger the value, the higher the transparency.

Example 1 A polyester film with a diameter of 50 μm and a transparency of 95% contains 10 mol% of sulfone units obtained by saponifying a copolymer of vinyl methyl sulfone and vinyl acetate,
Saponification degree of vinyl acetate unit 8υmol%, polymerization degree 'zso
A 10% water bath solution of modified PVA with a coating weight of 15% after drying.
It was coated to give a ratio of y/lri and dried to obtain an inkjet recording sheet. Table 1 shows the performance evaluation results of this sheet.

Example 2 Using art paper as a support substrate, a paper containing 5 mol% of sulfone units obtained by saponifying a copolymer of modified PVA, cytevinyldimethylsulfonamide, and vinyl acetate,
Saponification degree of vinyl acetate unit: 88 mol%, polymerization degree: 1000
The procedure was carried out in the same manner as in Example 1 except for using the following. The results are also shown in Table 1.

Example 3 Using high-quality paper as a supporting substrate, modified 1'VA was obtained by saponifying a copolymer of vinyl methyl sulfone and vinyl acetate, containing 5 mol% of sulfone units, and having a saponification degree of vinyl acetate units of 98. A coating solution with the following composition using modified PVA with a polymerization degree of SOO and a dry solid content of 20% by mole was applied.
It was coated with a bar coater so that it had a thickness of g□, and was dried to obtain a sheet.

The performance evaluation results of this sheet are also shown in Table 41.

The following margin Example 4 Using a commercially available inkjet paper as a support substrate, modified PvA containing 2 mol% of sulfone units obtained by saponifying a copolymer of vinyl dimethylsulfonamide and vinyl acetate, and vinyl acetate. Saponification degree of unit 85 mol%
, using modified PVa with a polymerization degree of 175o, the modified PVA
A recording sheet was obtained by impregnating and coating the dry surface of the sample with a size press so that the ratio was .y/rd. The performance evaluation results of this sheet are also shown in Table 1.

Comparative Examples 1-2 The same procedure as in Example 1 was carried out except that the following resins were used in place of the modified PVa used in the examples. The results are also shown in Table 1.

Comparative example 1: Polymerization 1i 1750, saponification degree 98.5 mol%
of l'VΔ.

Comparative Example 2: Equivalent mixture of polyvinylpyrrolidone and PVA with a degree of polymerization of 1750 and a saponification f of 88 mol% (7).

Comparative Examples 3 to 4 The same procedure as in Example 2 was carried out except that the following resins were used instead of the modified PVA used in Example 2. The results are also shown in Table 1.

Comparative Example 3: Polyacrylamide.

Comparative Example 4: Polyacrylamide and 31 combination Jfz7so.

etc. with PVa with saponification degree of 88 mol% quantity mixture.

Margin below Table 1

Claims (1)

[Claims] (1) An inkjet recording sheet having an ink absorption layer in and/or on the surface of a supporting substrate, wherein the absorption layer contains modified polyvinyl alcohol having a nonionic substituent containing a sulfone group. sheet.