JP2000238425A - Recording sheet for aqueous ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recording sheet for an aqueous ink exhibiting good water resistance together with recording sheet itself and recording part with excellent ink absorbing dryability and image quality. SOLUTION: The recording sheet for an aqueous ink comprises (A) non- aqueous soluble cationic synthetic resin having (meth)acrylic monomer unit of 5 to 15 mass % having a quaternary ammonium structure, and (B) a water soluble part or completely saponified polyvinyl alcohol and/or N-vinylpyrrolidone homopolymer or copolymer. A ratio of the [(A)/(B)] is preferably 70/30 to 30/70 by mass.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording sheet for water-based ink, and more particularly to an ink jet recording sheet for obtaining a high-quality color image based on paper, plastic film, synthetic paper, metal sheet and the like. It concerns the seat.

[0002]

2. Description of the Related Art In recent years, with the spread of personal computers, printers with low noise and excellent image quality have been demanded. An ink jet printer has been put to practical use as one of the printers satisfying these requirements. In ink-jet printing, especially multicolor printing, a recording sheet provided with a special ink-absorbing layer having good ink absorbency is usually used.

[0003] As dyes for inks used in ink-jet printing, water-soluble dyes, especially anionic dyes, are mainly used in view of safety, light resistance, recording characteristics and the like. Therefore, in order to increase the affinity for ink and the ink absorbency in forming the ink absorbing layer of the recording sheet, a resin composition in which a water-soluble cationic synthetic resin is combined with water-soluble polyvinyl alcohol or polyvinyl pyrrolidone is used. Although a coating method (Japanese Patent No. 2133897) has been proposed, this method is excellent in the drying property and image quality of the ink, but the water resistance of the recording sheet itself and the recording portion is low.
It was not always satisfactory.

Further, a method of incorporating a basic latex polymer into an ink absorbing layer of a recording sheet (JP-A-57-3)
However, this method also has a problem that the water resistance is not sufficiently satisfied due to the effect of the surfactant used in the emulsion polymerization, and that the storage stability of the latex is poor.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art. The present invention not only has excellent ink drying properties and image quality, but also has good water resistance in both the recording sheet itself and the recording portion. It is intended to provide a recording sheet showing the property.

[0006]

[Means for Solving the Problems] That is, the present invention relates to (A)
A water-insoluble cationic synthetic resin containing 5 to 15% by mass of a (meth) acrylic monomer unit having a quaternary ammonium salt structure, and (B) a water-soluble partially or completely saponified polyvinyl alcohol, and / or The present invention also relates to a recording sheet for aqueous ink, provided with an ink absorbing layer comprising a homopolymer or copolymer of N-vinylpyrrolidone.

In the present invention, the cationic synthetic resin as the component (A) comprises at least one kind of copolymerizable (meth) acrylic monomer (a) having a functional group such as a quaternary ammonium salt. It is a synthetic resin derived from the vinyl monomer (b) component. The general formula of the component (a), which is a component of the resin, is the formula (I)

[0008]

Wherein R ¹ is a hydrogen atom or a methyl group;
Is O or NH, R ² and R ³ are each independently a carbon number of 1-4.
R ⁴ is a hydrogen atom or an optionally substituted alkyl group having 1 to 4 carbon atoms, n is an integer of 2 to 5, Y ⁻
Represents an anion which forms a salt]. R ⁴ in the formula is preferably a hydrogen atom or a methyl group in view of industrial availability. Further, Y ^- specifically a halogen ion ^{(Cl -, Br -, I} - , _{^{etc.), CH 3 OSO 3 -,}} C 2 H 5 SO 3 -, HSO 4
_{^{-, H 2 PO 4 -,}} CH 3 COO -, HCOO -, NO
_3- ^{and the} like.

Specific examples of the monomer (a) include inorganic acid salts, organic acid salts of dialkylaminoalkyl (meth) acrylates or dialkylaminoalkyl (meth) acrylamides, and quaternary ammonium salts with a quaternizing agent. can give. Here, as the inorganic acid salt, hydrochloride,
Sulfates, nitrates, phosphates and the like can be mentioned, and organic salts include acetate, formate and the like. Examples of the quaternizing agent include methyl chloride, diethyl sulfate, epihalohydrin, benzyl chloride and the like.

The dialkylaminoalkyl (meth) acrylates include dimethylaminoethyl acrylate, dimethylaminopropyl acrylate, dimethylaminobutyl acrylate, diethylaminoethyl acrylate, diethylaminopropyl acrylate, diethylaminobutyl acrylate, di-n-propylaminoethyl acrylate, Di-n-propylaminopropyl acrylate, di-n-propylaminobutyl acrylate, di-n-butylaminoethyl acrylate, di-
n-butylaminopropyl acrylate, di-n-butylaminobutyl acrylate, 1,1-dimethyl-3-
Dimethylaminopropyl acrylate, 2-methyl-3
-Dimethylaminopropyl acrylate and the like, and corresponding methacrylates.

The dialkylaminoalkyl (meth) acrylamides include dimethylaminoethylacrylamide, dimethylaminopropylacrylamide, dimethylaminobutylacrylamide, diethylaminoethylacrylamide, diethylaminopropylacrylamide, diethylaminobutylacrylamide, di-n
-Propylaminoethylacrylamide, di-n-propylaminopropylacrylamide, di-n-propylaminobutylacrylamide, di-n-butylaminoethylacrylamide, di-n-butylaminopropylacrylamide, di-n-butylaminobutylacrylamide , N- (1,1-dimethyl-3-dimethylaminopropyl) acrylamide, N- (2-methyl-3-dimethylaminopropyl) acrylamide and the like, and methacrylamide derivatives corresponding thereto.

The above-mentioned inorganic acid salts, organic acid salts and quaternary ammonium salts of dialkylaminoalkyl (meth) acrylates or dialkylaminoalkyl (meth) acrylamides can be used alone, respectively. Two or more kinds can be used in combination. The component (A) of the present invention is obtained by copolymerizing a dialkylaminoalkyl (meth) acrylate and / or a dialkylaminoalkyl (meth) acrylamide, which is a precursor of the component (a), with the component (b). Thereafter, treatment with an inorganic acid and / or an organic acid and / or a quaternizing agent is performed, and those obtained are included.

The vinyl monomer (b) used in the present invention includes styrene compounds such as styrene and vinyl toluene, olefins such as ethylene and propylene, halogenated olefins such as vinyl chloride and vinylidene chloride, and the like. Vinyl esters such as vinyl acetate and vinyl propionate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate,
Butyl (meth) acrylate, hexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, benzyl (meth) acrylate, 2-ethylhexyl (meth) acrylate Esters of (meth) acrylic acid with aliphatic alcohols having 1 to 18 carbon atoms, such as ethoxyethyl (meth) acrylate, (meth) acrylonitrile, other glycidyl groups, N-methylol groups, alkoxymethyl groups, amide groups And vinyl monomers having a functional group such as carboxyl group, hydroxyl group, methoxy group and sulfonic acid group, and vinyl monomers having two or more polymerizable unsaturated bonds.

Specific examples of the vinyl monomer having a functional group include N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide,
Ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-isobutoxymethyl (meth) acrylamide, (meth) acrylic acid, itaconic acid, maleic acid, (meth) Acrylamide, 2-hydroxyethyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate, vinyl sulfonic acid or a salt thereof can be mentioned.

Specific examples of the vinyl monomer having two or more polymerizable unsaturated bonds include aliphatic dienes such as butadiene and isoprene, ethylene glycol di (meth) acrylate, and tetraethylene glycol di (meth) ate. ) Acrylate, butylene glycol di (meth) acrylate, neopentyl glycol di (meth)
Poly (meth) acrylates such as acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, divinylbenzene, diallyl maleate, allyl (meth) acrylate, triallyl isocyanurate, triallyl cyanurate, Methylene bisacrylamide and the like can be mentioned.

Next, a method for producing the cationic synthetic resin as the component (A) in the present invention will be described. The component (a), which is a component of the cationic synthetic resin, and the vinyl monomer (b) copolymerizable therewith are copolymerized using a conventionally known polymerization method to obtain the cationic synthetic resin of the present invention.
For example, a polymerization initiator is added to the components (a) and (b) by a known solution polymerization method in a hydrophilic or water-miscible solvent,
The cation-based synthetic resin of the present invention can be obtained by copolymerization by stirring and heating under a nitrogen atmosphere. After the synthesis, if necessary, water or another solvent can be added.

Examples of the hydrophilic or water-miscible solvent used in the above polymerization include methanol, ethanol, n
-Propanol, isopropanol, n-butanol,
Alcohols such as secondary butanol, diacetone alcohol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, and butyl carbitol; ethers such as dioxane and tetrahydrofuran; ketones such as acetone and methyl ethyl ketone; and esters such as cellosolve acetate. .

Examples of the polymerization initiator include organic peroxides such as benzoyl peroxide, acetyl peroxide, lauroyl peroxide, decanoyl peroxide and tertiary butyl peroxide, azobisisobutyronitrile, azobisisopropyl Azo compounds such as dimethylvaleronitrile, triazobenzene, phenylazotriphenylmethane, and 1,1-azobiscumene are used alone or in combination. The amount of the polymerization initiator to be used is not particularly limited. However, since it is preferable to minimize the residual amount of the monomer and the remaining amount of the initiator, the polymerization initiator is used in an amount of 0.05 to 5% by mass based on the total amount of the monomer. It is desirable to use it.

When a solvent is used, the polymerization temperature depends on the boiling point of the solvent, but is preferably from 10 to 120 ° C., particularly preferably from 40 to 90 ° C. If the temperature is lower than 40 ° C., the polymerization rate of the monomer tends to decrease, which is not preferable. The method of introducing the monomer into the reaction system is not particularly limited. For example, the polymerization may be carried out by adding the whole amount first, or may be carried out by divided dropping or continuous dropping.

In the present invention, the cationic synthetic resin as the component (A) is prepared by limiting the proportion of the component (a) to 15% by mass or less and appropriately selecting the vinyl monomer (b) component to be combined. It must be water-soluble. If the cationic synthetic resin shows water solubility, the water resistance of the recorded matter is poor, and the effects of the present invention cannot be exhibited.

In the present invention, in the cationic synthetic resin of the component (A), the proportion of the component (a) must be 5% by mass or more. When the amount of the component (a) is less than 5% by mass, the drying property and sharpness of an image are poor.

In the present invention, the component (B) and / or
Alternatively, any conventionally known completely saponified polyvinyl alcohol can be used. For example, examples of the polyvinyl alcohol include Gohsenol GM-14L and GH-17 manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and Kuraray Poval PVA-210 and PVA-217 manufactured by Kuraray Co., Ltd.

In the present invention, any conventionally known homopolymer or copolymer of N-vinylpyrrolidone as the component (B) can be used. For example, as such a polymer, Lubiscol K-30 manufactured by BASF,
K-80, K-90 and the like can be mentioned.

In the present invention, paper, metal,
A cationic synthetic resin of the component (A) and a partially or completely saponified polyvinyl alcohol of the component (B) and / or N-
It is necessary to provide an ink absorbing layer made of a homopolymer or copolymer of vinylpyrrolidone. At this time, (A)
The ratio of / (B) is preferably from 70/30 to 30/70 mass ratio. When the amount of the component (A) is more than 70% by mass, the water resistance of the coating film tends to be inferior. 3
When the amount is less than 0% by mass, ink drying properties and image quality tend to be inferior, and ink cissing is likely to occur.

Further, in the resin composition containing the components (A) and (B), conventionally known epoxy resins, phenolic resins, melamine resins, urea resins, glyoxal, isocyanate compounds, aziridine compounds, oxazoline compounds, alkoxysilane compounds and the like can be used. The water resistance of the recording sheet can be further improved by blending a crosslinking agent to cure the ink absorbing layer. The amount of the crosslinking agent varies depending on the type, but is preferably 0.2 to 20% by mass based on the total resin solid content of the components (A) and (B). For example, in the case of a melamine resin-based cross-linking agent, if less than 0.2% by mass, the compounding effect is hardly seen, and if more than 20% by mass, the water resistance of the recording sheet is improved, but the drying property of the ink and The image quality of the recording layer tends to decrease, which is not preferable.

In addition to the above, surfactants such as nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants are used to improve the surface condition and performance of the ink absorbing layer. , Silicone resins, wetting agents, electrolyte polymers, clays, fillers such as calcium carbonate, colloidal sols such as silica sol and alumina sol, and so on.

The ink absorbing layer is formed by coating a resin composition containing the components (A) and (B) on a base sheet by an air knife coat, blade coat, bar coat, gravure coat, curtain coat, roll coat, spray coat, or the like. And the solvent is volatilized by an appropriate means. Substrate sheets include plastic film, synthetic paper, paper with controlled size, air permeability, smoothness, etc., processed paper with a barrier coating layer formed by resin coating or extrusion coating of thermoplastic resin, resin impregnated paper , A metal sheet or the like can be used. These base sheets may optionally be provided with an anchor coat on the base material in order to increase the adhesiveness of the recording layer.

The recording sheet for water-based ink of the present invention is used not only for ink-jet printing recording using water-based ink, but also for drafting film used for making an underprint drawing with water-based ink, water-based ball-point pen, water-based ink felt pen, etc. Can also be used for XY plotter films and OHP sheets.

The ink-jet print recording method and the method for evaluating various characteristics in the present invention will be described.

Inkjet printing and recording method Personal computer FMV-51 manufactured by Fujitsu Limited
As an information output device of 33DPS, an ink jet printer PM-750C manufactured by Epson Corporation is used.
A predetermined color pattern (cyan, magenta, yellow, and black and their combined colors) and a character pattern (font size: 2 to 8 points) under the conditions of the HP mode at 22 ± 2 ° C. and 45% RH And subjected to ink drying recording, evaluation of ink drying properties, image quality (bleeding, density unevenness) and water resistance of the recorded matter.

Evaluation Method of Ink Drying Property Ink drying property was determined by the following criteria based on the degree of contamination of the recording material surface with ink by rubbing the recording portion once with a finger immediately after printing and 15 seconds after printing with a printer.
It was rated on a scale. 5: very good (recording layer is not stained immediately after recording) 4: good (immediately after recording, stain on recording layer is within 1 mm) 3: slightly good (recording layer is stained 15 seconds after recording, 1)
mm) 2: Slightly inferior (5 minutes after recording, stain on recording layer 5)
mm) 1: bad (recording layer stain 10 even after 15 seconds from recording)
mm or more)

Evaluation method of bleeding Five-step evaluation was performed by visual observation according to the following criteria. 5: Very good (no bleeding at all) 4: Good (several dots exist at the boundary) 3: Slightly good (wavy formation of dots at the boundary) 2: Slightly poor (within 0.5 mm bleeding) 1: Poor ( (Bleed 0.5mm or more)

Evaluation method of density unevenness Five-step evaluation was performed by visual observation according to the following criteria. 5: Very good (no spots, uniform and clear dots) 4: Good (no spots) 3: Slightly good (dots and traces) 2: Slightly poor (no dots) 1 : Insufficient (dots are crushed without traces, and spots are present even on the ink single color recording layer)

Evaluation method of water resistance of recorded matter One drop of water was dropped on the surface of the recorded matter, and one minute later, it was lightly rubbed with a cotton swab and evaluated according to the following criteria. 5: very good (no dissolution of the recording layer and no discoloration of the ink) 4: good (no dissolution of the recording layer but a trace of water droplets remaining) 3: somewhat good (no dissolution of the recording layer but discoloration of the ink) 2: Slightly inferior (the recording layer peels off like fragments) 1: Poor (the recording layer dissolves easily)

Evaluation Method of Water Resistance of Recording Sheet One drop of water was dropped on the surface of the recording sheet, and after 1 minute, the water resistance was evaluated by gently rubbing with a cotton swab. ：: good (does not dissolve in water) ×: bad (dissolves in water)

[0037]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. In the examples, percentages and parts representing the content or the used amount are based on mass unless otherwise specified.

Synthesis Example 1 60 parts of isopropanol was charged into a flask equipped with a reflux condenser, a thermometer, and a stirrer, heated to 80 ° C., and the inside of the reaction system was replaced with nitrogen. Next, 10 parts of (2-methacryloyloxyethyl) trimethylammonium chloride, 72 parts of methyl methacrylate, 18 parts of hydroxyethyl methacrylate, 40 parts of isopropanol and 1 part of 2,2′-azobisisobutyronitrile were charged at a constant rate over 2 hours. And supply it to the reaction system for reaction.
After keeping the temperature for a time, the mixture was diluted with 35 parts of water to complete the polymerization.
The resulting cationic synthetic resin solution was a colorless, transparent and uniform solution. In addition, the solvent of the present resin solution is completely volatilized,
It was again weighed so as to be 1 part of the cationic synthetic resin and 100 parts of water and was tried to be dissolved at 50 ° C., but was not dissolved.

Synthesis Example 2 Polymerization was carried out in the same manner as in Synthesis Example 1 except that (2-acryloyloxyethyl) trimethylammonium chloride was used as the quaternary ammonium salt-containing monomer to obtain a cationic synthetic resin solution. The solubility in water was examined in the same manner as in Synthesis Example 1, but was not dissolved.

Synthesis Example 3 In Synthesis Example 1, the blending amounts of methyl methacrylate and hydroxyethyl methacrylate were 64 parts and 16 parts, respectively.
And polymerization was carried out in the same manner except that 10 parts of acrylic acid were used to obtain a cationic synthetic resin solution. The solubility in water was examined in the same manner as in Synthesis Example 1, but was not dissolved.

Comparative Synthesis Examples 1 to 4 In Synthesis Example 1, the ratio of methyl methacrylate / hydroxyethyl methacrylate was kept constant at 72 parts / 18 parts, and (2-methacryloyloxyethyl) trimethylammonium chloride was added in 2, 20, 30, respectively. 50
Polymerization was carried out in the same manner except that parts were used to obtain Comparative Synthetic Resin Solutions 1 to 4. The solubility in water was examined in the same manner as in Synthesis Example 1. As a result, Comparative Synthesis Example 1 did not dissolve at all and Comparative Synthesis Example 2 hardly dissolved, but Comparative Synthesis Examples 3 and 4 dissolved easily.

Next, Examples and Comparative Examples using the above-mentioned resins will be described.

Examples 1-8, Comparative Examples 1-7 Cationic synthetic resins of synthetic examples and comparative synthetic examples, partially saponified polyvinyl alcohol (Gohsenol GM-14L manufactured by Nippon Synthetic Chemical Industry Co., Ltd.), polyvinylpyrrolidone (B
Rubiscol K-90 manufactured by ASF) and a melamine resin (Sumimar MC-1 manufactured by Sumitomo Chemical Co., Ltd.) as a cross-linking agent were blended as shown in Table 1, and the solid content was further reduced to 20 by ion-exchanged water.
% To prepare a coating composition. Polyester film (Melinex 705 manufactured by DuPont)
Using a bar coater so that the film thickness becomes 10 microns.
After drying for a minute, a recording sheet was obtained. Inkjet printing recording was performed by the above method, and evaluation of ink drying property, image quality, and water resistance of the recorded matter were performed. The water resistance of the recording sheet itself was also evaluated. Table 2 summarizes the results.

[0044]

[Table 1]

[0045]

[Table 2]

The inks of Examples 1 to 8 according to the present invention have better drying properties of the inks than those of Comparative Examples 1 to 5, and have excellent compatibility between image clarity (bleeding, density unevenness) and water resistance. Was.
On the other hand, those of Comparative Examples 6 and 7 were inferior in water resistance because the cationic synthetic resin was soluble in water.

[0047]

As described above, the recording sheet of the present invention is excellent in ink drying property, and has an extremely excellent balance between image clarity (bleeding and density unevenness) and water resistance. Suitable for overhead projector sheets, etc.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroyuki Fujita 3-8-40 Kitadamiya, Tokushima City, Tokushima Prefecture Hitachi Chemical Polymer Co., Ltd. Tokushima Plant F-term (reference) 2H086 BA15 4F006 AA02 AA35 AB12 AB20 AB24 BA01 CA01 4F100 AK02A AK02J AK21A AK25A AK25J AK25K AK41B AL05A AT00B BA02 BA10A BA10B CA02A GB90 JB07 JD14A YY00A 4L055 AG57 AG64 AG71 AG80 AG93 AH50 AJ02 BE08 EA32 FA15 FA19 GA09

Claims (4)

[Claims] 1. A water-insoluble cationic synthetic resin containing 5 to 15% by mass of a (meth) acrylic monomer unit having a quaternary ammonium salt structure, and (B) a water-soluble portion. Or fully saponified polyvinyl alcohol, and / or N-
A recording sheet for water-based ink provided with an ink absorbing layer comprising a vinylpyrrolidone homopolymer or copolymer. 2. The ratio of (A) to (B) [(A) / (B)]
The recording sheet for an aqueous ink according to claim 1, wherein the ratio is 70/30 to 30/70 mass ratio. 3. The recording sheet according to claim 1, wherein the recording sheet is a sheet for ink-jet printing recording. 4. The ink absorbing layer according to claim 1, wherein a crosslinking agent of 0.2 to 20% by mass based on the total resin solid content of the components (A) and (B) is blended to cure the ink absorbing layer. Recording sheet for aqueous ink.