JP2604367B2 - Ink jet recording sheet with excellent water resistance - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording sheet, and more particularly to an ink jet recording sheet having excellent ink absorbency and extremely excellent water resistance.

B. Prior Art The ink jet recording system has been applied to facsimile machines, various printers, and the like because of low noise, easy colorization, and high-speed recording. Conventionally, ordinary paper has been used as a recording material used in the ink jet recording method. However, as the performance of an ink jet recording apparatus has been improved, such as by increasing the speed of recording or increasing the number of colors, more advanced properties have been required for ink jet recording sheets. That is, first, the ink absorption speed is high, second, the diameter of the ink dot does not become larger than necessary, and third, the water resistance of the ink jet recording sheet itself is high.

In order to satisfy these requirements, various studies have been made, such as using paper or a water-soluble resin as an absorbent for an aqueous ink jet ink.However, if the ink absorption speed is increased, the ink dot diameter becomes larger than necessary. At present, it does not reach a practical level requirement, for example, the water resistance is remarkably lowered.

C. Problems to be Solved by the Present Invention An object of the present invention is to provide an ink jet recording sheet which satisfies the above-mentioned requirements and is particularly excellent in ink absorbency and water resistance.

Still another object of the present invention is to provide transparency that can be used for observation by projecting a recorded image on a screen or the like by an optical device such as a slide or OHP, or can be used for transmitted light observation such as a color display. An object of the present invention is to provide an excellent ink jet recording sheet.

D. Means for Solving the Problems The present inventors have solved the above problems, and as a result of diligent studies to achieve the above object, as a result, the support base has a carboxyl group-containing olefinically unsaturated monomer unit. A modified polyvinyl alcohol having a content of 0.1 to 10 mol% and a degree of saponification of 50 to 100 mol% (hereinafter, polyvinyl alcohol is abbreviated as PVA) and a waterproofing agent containing two or more epoxy groups or ethyleneimine groups in the molecule. The ink jet recording sheet containing the ink jet recording sheet was found to be an ink jet recording sheet excellent in ink absorbency and extremely excellent in water resistance, and was completed to complete the present invention.

The carboxyl-modified PVA used in the present invention can be obtained by saponifying a copolymer of a vinyl ester and a carboxyl group-containing olefinically unsaturated monomer.

As the vinyl ester used in the present invention,
Vinyl acetate, vinyl propionate and vinyl formate are mentioned, but vinyl acetate is preferred from the viewpoint of economy.

Further, as the carboxyl group-containing olefinically unsaturated monomer used in the present method, for example, maleic acid,
Dicarboxylic acids such as fumaric acid and itaconic acid, their anhydrides, their salts and their alkyl esters, monocarboxylic acids such as (meth) acrylic acid, their salts and their alkyl esters, and the like. preferable.

When the above-mentioned copolymerization is carried out, other copolymerizable monomers other than these, for example, ethylene, propylene, styrene, alkyl vinyl ether, vinyl versatate, (meth) acrylamide, trimethyl-3- ( 1-
(Meth) acrylamide-1,1-dimethylpropyl) ammonium chloride, trimethyl-3- (1- (meth) acrylamide-1,1-dimethylethyl) ammonium chloride, trimethyl-3- (1- (meth) acrylamidopropyl) A small amount of a monomer having an amino group or an ammonium base such as ammonium chloride, N-vinylimidazole, N-vinyl-N-methylimidazole and quaternary compounds thereof can also be used.

The content of the carboxyl group in the modified PVA used in the present invention is 0.1 to 10 mol%, preferably 0.5 to 10 mol%, as the content of the carboxyl group-containing olefinically unsaturated monomer unit (hereinafter abbreviated as carboxyl group unit). ~ 5
It is selected from the range of mol%. The saponification degree of the vinyl ester unit is selected from the range of 50 to 100 mol%, preferably 70 to 95 mol%. Further, the degree of polymerization of the modified PVA is not particularly limited, but is usually 50 to 3000, preferably 100 to 2
Selected from 500 ranges.

Further, the carboxyl-modified PV used in the present invention
As A, modified PVA having a carboxyl group, (meth) acrylamide, (meth) acrylonitrile,
Those obtained by grafting or block copolymerizing (meth) acrylic acid esters can also be used.

Examples of the water-proofing agent containing two or more epoxy groups or ethyleneimine groups in the molecule used in the present invention include:
For example, a reaction product of ethylene oxide, propylene oxide, trimethylolpropane, glycerin or a condensate thereof with epichlorohydrin, a reaction product of a polyamide resin obtained by condensation of an alkylpolyamine compound with an alkyldicarboxylic acid and epichlorohydrin, hexamethylene A reaction product of diisocyanate or methylenebisdiphenyl diisocyanate with ethyleneimine is exemplified.

The mixing ratio of the modified PVA and the water-proofing agent used in the present invention is 100/5 to 100/50 by weight, preferably 100/1.
It is selected from the range of 0 to 100/40.

The modified PVA and the waterproofing agent used in the present invention can be used alone or in combination with other water-soluble or water-dispersible resins.

Other water-soluble or water-dispersible resins that can be used in combination include albumin, gelatin, casein, starch, gum arabic, cellulose derivatives such as methylcellulose, hydroxyethylcellulose, polyamide resins, melamine resins, ordinary unmodified PVA, poly (meta). ) Nonionic water-soluble resins such as acrylamide and polyvinylpyrrolidone;
CMC, anionic water-soluble resins such as sodium poly (meth) acrylate, sodium alginate, water-soluble polyester, polyethyleneimine, polyvinylamine, polyallylamine, polyallylamine sulfone copolymer or their ammonium salts, cationized starch, cation Poly (meth) acrylamide, cation-modified PVA,
Cationic water-soluble resins such as cationized polyamide resins,
SBR latex, NBR latex, vinyl acetate emulsion, ethylene / vinyl acetate copolymer emulsion,
Water-dispersible resins such as (meth) acrylic ester emulsions and vinyl chloride emulsions are exemplified.

When these water-soluble or water-dispersible resins are used in combination with the modified PVA and the water-proofing agent used in the present invention, the combined ratio is 100 parts by weight or less based on 100 parts by weight of the modified PVA of the present invention, preferably Used at 50 parts by weight or less.

Further, the modified PVA and the waterproofing agent used in the present invention can be used in combination with a filler such as silica, clay, talc, diatomaceous earth, zeolite, calcium carbonate, alumina, zinc oxide, and satin white. In this case, the combination ratio is different between the recording sheet having excellent transparency and the other cases.
Filler is 1/100 to 100/1 by weight, preferably 5/100 to 100/5
Is selected from the range.

The blend of the modified PVA and the water-proofing agent used in the present invention can be used as an ink-absorbing layer because it itself has excellent ink-absorbing properties. To form a layer comprising the above composition, and can be used as a water-resistant layer.

As the support substrate used in the present invention, any of conventionally known support substrates having transparency and opacity can be used. Examples of the transparent support substrate include films such as polyester, polystyrene, polyvinyl chloride, polymethyl methacrylate, cellulose acetate, polycarbonate, polyimide, cellophane, and celluloid, sheets, and highly transparent paper. Examples of the opaque support substrate include general paper, pigment-coated paper, cloth, wood, metal plate, synthetic paper, synthetic resin film or sheet subjected to opacity treatment.

In the case of an ink jet recording sheet having excellent transparency, which is one of the objects of the present invention, a transparent support substrate is used.

In the present invention, as a method of incorporating a blend of modified PVA and a water-proofing agent in a supporting substrate, an aqueous solution of the above-described blend of modified PVA and a water-proofing agent, or another water-soluble or water-dispersible resin or An aqueous solution or an aqueous dispersion of the mixture with the filler is impregnated into the supporting substrate by an ordinary coating method such as a size press, an air knife coater, a roll coater, a bar coater, and a blade coater,
For example, a method of forming a coat layer on the upper surface of the supporting substrate or on both the upper surface and the lower surface can be used.

When the supporting substrate is paper, a method of internally adding the above aqueous solution or aqueous dispersion during papermaking may be used.

The aforementioned modification in the ink jet recording sheet of the present invention.
There is no particular restriction on the content of the composition comprising PVA and waterproofing agent, usually 0.1 to 200 g / m ² preferably 1~100g
/ m ² is used.

E. Effects and Effects of the Invention The reason why the ink jet recording sheet of the present invention is excellent in ink absorbency and remarkably excellent in water resistance is not fully understood, but is presumed as follows.

The composition comprising the carboxyl-modified PVA used in the present invention and a water-resistant agent containing two or more epoxy groups or ethyleneimine groups in the molecule is water-soluble before film formation and hydrophilic after film formation. However, it is presumed that the obtained film has remarkably high water resistance, so that it is possible to form an ink jet recording sheet having remarkably excellent water resistance as well as ink absorbability.

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited thereto. In the examples, “%” and “parts” are used unless otherwise specified.
Represents a weight standard.

 In addition, the measuring method of various physical properties in an Example is shown below.

(1) Ink jet recording method Using a recording apparatus having an on-demand type ink jet recording head having a discharge orifice diameter of 60 μm, color ink jet recording was performed using the following four colors of ink, and the recording characteristics were evaluated.

Yellow ink (composition) CI Acid Yellow 2.3 2 parts Diethylene glycol 30 parts Water 70 parts Magenta ink (Composition) CI Acid 32 32 parts Diethylene glycol 30 parts Water 70 parts Cyan ink (Composition) CI Direct Blue 86 2 parts Diethylene glycol 30 parts Water 70 Part Black ink (composition) CI direct black 19 2 parts Diethylene glycol 30 parts Water 70 parts (2) Ink absorption speed After ink jet recording, the print on the recording sheet is rubbed with a finger at regular time intervals until the printed portion does not change The time was measured. The shorter the time, the higher the ink absorption speed.

(3) Bleeding degree The diameter of the printed dot was measured with a stereoscopic microscope, and the number of times the ink droplet became larger was shown. The lower the magnification, the less bleeding.

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

(5) Water resistance Water is applied to the printed portion of the sheet after the ink jet recording,
When rubbing with a finger, it was determined whether or not the printed portion was dissolved or bleed. 5: No change ~ 1: Bleeding, dissolution.

Example 1 A polyester sheet having a thickness of 50 μm and a transparency of 95% contains 1 mol% of a carboxyl group unit obtained by saponifying a copolymer of vinyl acetate and itaconic acid, and the degree of saponification of the vinyl acetate unit is 88 mol. %, 100 parts of modified PVA having a degree of polymerization of 1750, and a reaction product of a polyamide resin and epichlorohydrin 30
And a 10% aqueous solution containing the above components was applied so that the applied amount after drying was 15 g / m ^2, and dried to obtain an inkjet recording sheet. The ink absorption speed, bleeding degree, transparency,
Table 1 shows the water resistance.

Example 2 The procedure of Example 1 was repeated, except that a reaction product of methylenebisdiphenyl diisocyanate and ethyleneimine was used instead of the water-proofing agent used in Example 1. The results are shown in Table 1.

Comparative Examples 1 to 5 The same procedure as in Example 1 was carried out except that the following resin was used instead of the blend of the modified PVA and the waterproofing agent used in Example 1. The results are shown in Table 1.

Resin used in Comparative Example 1: only PVA having a polymerization degree of 1750 and a saponification degree of 98.5 mol%.

Resin used in Comparative Example 2: only modified PVA used in Example 1.

Resin used in Comparative Example 3: only the waterproofing agent used in Example 1.

 Resin used in Comparative Example 4: polyvinylpyrrolidone.

Resin used in Comparative Example 5: Cation-modified PVA containing 2 mol% of cationic groups, having a polymerization degree of 1750 and a saponification degree of 88 mol%
only.

Example 3 The composition used in Example 1 was applied on the polyvinylpyrrolidone layer of the ink jet recording sheet obtained in Comparative Example 4 so that the dry solid content was 5 g / m ^2, and dried to perform ink jet recording. Sheet was obtained. The results are shown in Table 1.

Example 4 The composition used in Example 2 was applied onto the cation-modified PVA layer of the ink jet recording sheet obtained in Comparative Example 5 so as to have a dry solid content of 10 g / m ^2, and dried to form an ink jet recording sheet. I got a sheet. The results are shown in Table 1.

Examples 5 to 10 Art paper was used as a support substrate, and 2% by mole of a maleic anhydride unit obtained by saponifying a copolymer of vinyl acetate and maleic anhydride was used as a modified PVA. Was used in the same manner as in Example 1 except that a modified PVA having a degree of polymerization of 93 mol% and a degree of polymerization of 1800 was used, and glycerol polyglycidyl ether (a reaction product of glycerin and epichlorohydrin) was used as a water-proofing agent in the ratio shown in Table 2. Thus, an ink jet recording sheet was obtained. Table 2 shows the ink absorption rate, bleeding degree, and water resistance of the obtained sheet.

Example 11 Using a high-quality paper as a supporting substrate, a coating liquid having the following composition using the composition used in Example 1 was applied by a bar coater so that the dry solid content was 20 g / m ² , dried, and recorded. Sheet was obtained. The ink absorption speed, bleeding degree,
Table 3 shows the water resistance.

Comparative Example 6 The same operation as in Example 11 was carried out except that the PVA used in Comparative Example 1 was used instead of the formulation used in Example 11. Table 3 also shows the results.

Example 12 Using high-quality paper as a supporting substrate, the composition used in Example 2 was applied so as to have a dry solid content of 5 g / m ² and dried to obtain a recording sheet. Table 4 shows the performance of this sheet.

Comparative Example 7 The procedure was as in Example 12, except that polyvinylpyrrolidone was used instead of the formulation used in Example 12.
The results are shown in Table 4.

Comparative Examples 8 to 10 The same operation as in Example 1 was performed except that the following resin was used instead of the composition used in Example 1. The results are shown in Table 5.

Resin used in Comparative Example 8: Modified resin containing 0.08 mol% of a carboxyl group unit obtained by saponifying a copolymer of vinyl acetate and itaconic acid, wherein the degree of saponification of the vinyl acetate unit is 88 mol% and the polymerization degree is 1750. PVA1
Reaction product of 00 parts, polyamide resin and epichlorohydrin
30 parts.

Resin used in Comparative Example 9: Modified resin containing 11 mol% of a carboxyl group unit obtained by saponifying a copolymer of vinyl acetate and itaconic acid, wherein the vinyl acetate unit has a saponification degree of 88 mol% and a polymerization degree of 1750. PVA100
Reaction product of part and polyamide resin with epichlorohydrin 30
Department.

Resin used in Comparative Example 10: Modified resin containing 1 mol% of a carboxyl group unit obtained by saponifying a copolymer of vinyl acetate and itaconic acid, wherein the vinyl acetate unit has a saponification degree of 47 mol% and a polymerization degree of 1750. PVA100
Reaction product of part and polyamide resin with epichlorohydrin 30
Department.

 ──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-61-102286 (JP, A) JP-A-60-72785 (JP, A) JP-A-61-189986 (JP, A) 59239 (JP, B2)

Claims (2)

(57) [Claims] (1) a supporting substrate comprising a modified polyvinyl alcohol having a carboxyl group-containing olefinically unsaturated monomer unit content of 0.1 to 10 mol% and a saponification degree of 50 to 100 mol%, and two or more epoxy groups or An ink jet recording sheet excellent in water resistance, comprising a water-proofing agent containing an ethyleneimine group. 2. A modified polyvinyl alcohol and 2 in the molecule.
The mixing ratio with the water-proofing agent containing two or more epoxy groups or ethyleneimine groups is the former / latter = 100/5 to 100/5 by weight.
2. The ink jet recording sheet excellent in water resistance according to claim 1, wherein the value is 0.