JP2003306888A - Paper for combined offset printing/ink-jet printing use - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper for the combined offset printing/ink-jet printing use, especially a paper giving no staining of printed images even by carrying out the offset printing and the ink-jet printing in the same line. <P>SOLUTION: A plain paper composed mainly of fibrous pulp and a filler is sized with a sizing agent containing a water-soluble modified polyamine resin and a cationic vinyl polymer. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to offset printing /
The present invention relates to a combined inkjet printing paper, and more particularly to a combined offset printing / inkjet printing paper that does not stain a printed image even when offset printing and inkjet printing are performed in the same line.

[0002]

[Problems to be Solved by the Prior Art and Invention] Usage notifications, bill notifications, and receipts from public and quasi-public institutions such as local governments, Social Insurance Agency, National Tax Agency, Waterworks Bureau, NTT, electric power, gas companies, etc. Releasable pressure-sensitive postcards used for letter notifications, usage amount guidance from financial institutions such as banks, life insurance companies, securities companies, balance notifications, and reminder letters; delivery slips for courier services;
The address label or the like of the direct mail is composed of a formal part consisting of display and drawing of items necessary for these documents and a specific content part which is different for each notified person. Recently,
With the development of information systems, the above-mentioned specific contents are often electronically recorded by the sender of documents, so that such contents are often printed by an inkjet method.

However, since it is advantageous in terms of efficiency and cost to perform the above-mentioned formal part by offset printing, a document is created by performing both offset printing and ink jet printing on the same recording paper. However, conventional inkjet recording paper often contains oxidized starch in order to make the inkjet receiving layer absorb water, and this oxidized starch is added to acidic dampening water during offset printing with process ink, UV ink, etc. There is a problem that it elutes and is transferred to the printing plate, and the printed image is stained. In particular, since the conventional inkjet recording paper is a coated paper having the inkjet receiving layer overcoated, oxidized starch is easily eluted. In addition, conventional inkjet recording paper also uses a cationic dye fixing agent (cationic polymer) or waterproofing agent in order to improve the water resistance of the inkjet ink received on the address side during postal delivery in the rain. However, the water resistance has not reached a satisfactory range.

At present, when offset printing and ink jet printing are performed on the same recording paper, they are performed on separate lines. At this time, after offset printing, the paper is often rewound before inkjet printing, but this is disadvantageous in terms of efficiency and cost. Therefore, in the future, it is desired to provide an inkjet head in the offset printing machine line and perform offset printing and inkjet printing in the same line. But in this case inkjet printing needs to be done very fast,
Ink jet recording paper is required to have excellent ink fixability and water resistance capable of withstanding dampening water during offset printing.

Therefore, an object of the present invention is to offset print /
It is an object of the present invention to provide a paper for combined inkjet printing, and particularly a paper for combined offset printing / inkjet printing in which the printed image is not stained even when offset printing and inkjet printing are performed in the same line.

[0006]

As a result of earnest research in view of the above object, the present inventors have found that a fibrous pulp and a filler are prepared by using a sizing agent containing a water-soluble modified polyamine resin and a cationic vinyl polymer. It was discovered that by performing sizing on plain paper mainly composed of, it is possible to obtain a combined offset printing / inkjet printing paper that does not stain the printed image even if offset printing and inkjet printing are performed in the same line, and the present invention has been conceived. did.

That is, the combined offset printing / inkjet printing paper of the present invention is characterized in that it is sized using a sizing agent containing a water-soluble modified polyamine resin and a cationic vinyl polymer.

The water-soluble modified polyamine resin is preferably an ionene polymer composed of a copolymer of epihalohydrin and at least one member selected from the group consisting of aliphatic amines, alicyclic amines and aromatic amines. Formula (1):

[Chemical 13] (However, R ₁ and R ₂ independently represent an alkyl group having 1 to 8 carbon atoms which may have a substituent, an arylalkyl group or an alicyclic alkyl group, and m represents an integer of 10 to 1500, X ^-
Represents a counter ion. An ionene polymer composed of the structural unit represented by the formula (1) is preferable.

The cationic vinyl polymer has the general formula (2):

[Chemical 14] The quaternary ammonium salt group represented by and / or the general formula (3):

[Chemical 15] (However, in the general formulas (2) and (3), R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ is an alkyl group having 1 to 8 carbon atoms, aryl An alkyl group or an alicyclic alkyl group, wherein X ⁻ is a counter ion is preferable. The counter ion X ⁻ in the general formulas (2) and (3) is generally a halogen ion, an alkyl sulfate ion, an alkyl or aryl sulfonate ion, an alkyl sulfite ion, or an alkyl phosphate ion.

The cationic vinyl polymer has the general formula (4):

[Chemical 16] Structural unit I represented by the general formula (5)

[Chemical 17] (However, in the general formulas (4) and (5), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an optionally branched carbon atom of 1 to 1.
10 represents an alkylene group, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 to 4 carbon atoms.
8 represents an alkyl group, an arylalkyl group or an alicyclic alkyl group, and X ⁻ represents a counter ion. )
II, general formula (6):

[Chemical 18] Structural unit III represented by, and the general formula (7):

[Chemical 19] (However, in the general formulas (6) and (7), R ₃ and R ₅ are the same as those in the general formula (4), and X ⁻ represents a counter ion.) Made of at least one of the following (hereinafter referred to as cationic vinyl polymer (A))
Is more preferable. By using the cationic vinyl polymer (A), the color developability is improved.

The cationic vinyl polymer has the general formula
(Four):

[Chemical 20] Structural unit I represented by the general formula (5):

[Chemical 21] (However, in the general formulas (4) and (5), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an optionally branched carbon atom of 1 to 1.
10 represents an alkylene group, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 to 4 carbon atoms.
8 represents an alkyl group, an arylalkyl group or an alicyclic alkyl group, and X ⁻ represents a counter ion. )
II, general formula (6):

[Chemical formula 22] Structural unit III represented by, and the general formula (7):

[Chemical formula 23] (However, in the general formulas (6) and (7), R ₃ and R ₅ are the same as those in the general formula (4), and X ⁻ represents a counter ion.) And at least one selected from the general formula (8):

[Chemical formula 24] (However, R ₈ represents hydrogen or a methyl group, R ₉ is an optionally branched alkylene group having 4 or less carbon atoms, R ₁₀ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and n is 1 to 30. It is composed of a structural unit V represented by
To at least one selected from the group consisting of IV): (constituent unit V) in a weight ratio of 30 to 99:70 to 1 and a number average molecular weight of 5 × 10 ^{3 to} 3 × 10 ⁵ (Hereinafter, referred to as a cationic vinyl polymer (B)) can also be used. By using the cationic vinyl polymer (B), the color developability is improved. The weight ratio of (at least one selected from the group consisting of structural units I to IV) :( structural unit V) of the above copolymer is preferably 50 to 95:50 to 5.

The content of the ionene polymer is preferably 5 to 95% by weight based on 100% by weight of the total amount of the ionene polymer and the cationic vinyl polymer. This allows the ionene polymer and the cationic vinyl polymer to exert a synergistic effect on each other.

In order to further improve the print density, color developability and water resistance, it is preferable to add a water-soluble soybean polysaccharide to the sizing agent. By forming a pseudo-crosslinked product of water-soluble soybean polysaccharide and water-soluble modified polyamine resin and / or cationic vinyl polymer (cationic polymer), these cationic polymers do not penetrate into the paper layer and remain near the surface For,
It is believed that the cationic polymer can improve ink fixability and color developability. Further, it is preferable to add an aqueous resin to the sizing agent. This improves the solubility or affinity for the water-based ink. Further, in order to enhance the water resistance of the image, it is preferable to further add a surfactant. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and the bleeding is improved.

The reason why the offset printing / inkjet printing combined paper of the present invention does not stain the printed image even when offset printing and inkjet printing are performed in the same line is not necessarily clear, but it is excellent in water resistance and is a water-soluble modified polyamine-based paper. By sizing a sizing agent containing a resin and a cationic vinyl polymer having a high ink affinity to plain paper mainly composed of fibrous pulp and a filler, the water-soluble modified polyamine resin and the cationic vinyl polymer are separated from each other. It exerts a synergistic effect without losing the advantages of, and during offset printing, the oil and water in the offset printing ink repel smoothly to form a stain-free printed image, and because the ink dries quickly, inkjet printing is quick. It is thought that this can be done.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Offset printing according to the present invention will now be described.
The inkjet printing paper will be described in detail. [A] Sizing agent (1) Water-soluble modified polyamine-based resin and cationic vinyl polymer (a) Water-soluble modified polyamine-based resin By using a water-soluble modified polyamine-based resin, it is generally possible to obtain excellent water resistance on recorded images on printing paper. It is possible to impart sex. The water-soluble modified polyamine resin is disclosed, for example, in U.S. Pat.No. 3,738,945 and Canadian Patent No. 1096070, and at least one selected from the group consisting of aliphatic amines, alicyclic amines and aromatic amines, and epihalohydrin. An ionene polymer having a quaternary ammonium salt group in its main chain and exhibiting cationicity; a reaction product of an aliphatic amine and epihalohydrin disclosed in JP-B-53-44567; Reaction product of polyalkylenepolyamine or alkylenediamine and epihalohydrin disclosed in JP-A-61-55286;
No. 124, a reaction product of a specific monoamine and epihalohydrin; and a reaction product of an amino compound, nitrite, and epihalohydrin disclosed in JP-A No. 63-227893.

As the water-soluble modified polyamine resin used in the present invention, the above ionene polymer is preferable. The method for producing such an ionene polymer is disclosed in the above-mentioned US Pat. No. 3,738,945 and Canadian Patent No. 1096070, and can be easily synthesized according to such a known conventional method. For example, a compound having a halogen atom at one molecular end and a secondary or tertiary nitrogen atom at the other molecular end is produced by ring-opening addition of an aliphatic amine and epihalohydrin that are almost equivalent in terms of the number of moles. It is obtained by polymerizing. The addition of epihalohydrin to the aliphatic amine may be divided addition, batch addition or continuous addition.

As the amine, dimethylamine, diethylamine, dipropylamine, diisopropylamine,
Dibutylamine, di-secondary butylamine, ditertiary butylamine, diisobutylamine, diamylamine, diisoamylamine, ditertiary amylamine, dihexylamine, N-methylpropylamine, N-
Methylisopropylamine, N-methylbutylamine, N-
Ethylbutylamine, N-methylcyclopentylamine,
Aliphatic secondary amines such as N-methylhexylamine, N-cyclohexylisopropylamine and N-ethylcyclohexylamine; cyclic aliphatic secondary amines such as dicyclohexylamine; aniline, methylaniline, ethylaniline,
Aromatic secondary amines such as diphenylamine may be mentioned. Examples of the epihalohydrin reacted with the amine include epichlorohydrin and epibromhydrin. Dialkylamines are preferred, and ionene polymers obtained by reacting dimethylamine and / or diethylamine with epichlorohydrin are more preferred.

The ionene polymer as described above has the general formula (1):

[Chemical 25] (However, R ₁ and R ₂ independently represent an alkyl group having 1 to 8 carbon atoms which may have a substituent, an arylalkyl group or an alicyclic alkyl group, and m represents an integer of 10 to 1500, X ^-
Represents a counter ion. Those composed of the structural unit represented by The ionene polymer used in the present invention may be not only a single component but also a mixture thereof, as long as it is a polymer satisfying the above conditions. R ₁
And R ₂ independently of one another have 1 to 1 carbon atoms which may have a substituent.
An alkyl group of 6 is preferred. This improves the water dispersibility of the ionene polymer when preparing the sizing agent. General formula
(1) pair in the ion X ^- is generally a halogen ion, an alkylsulfate ion, an alkyl or aryl sulfonate ion, alkyl sulfite ion, or alkyl phosphate. These counter ions can be exchanged with each other by ion exchange or the like.

Mn of the ionene polymer is 1000 to 200,000
Is preferred. When the Mn is less than 1000, the fixability of the ionene polymer to the pulp is deteriorated, and the ionene polymer itself exudes together with the dye when exposed to water, which is not preferable in terms of water resistance, and film-forming property. Is low, the coating film becomes sticky even when a film is formed, and the sharpness of the printed matter is insufficient when inkjet printing is performed. On the other hand, if it exceeds 200,000, the solubility of the ionene polymer will be insufficient and the ink absorbency will be lowered. More preferable Mn is 1500 to 100000. Mn can be determined by GPC (gel permeation chromatography) measurement.

By using the ionene polymer as described above, excellent water resistance can be imparted to the recorded image on the printing paper. Generally, the dyes used for inkjet recording are mainly acid dyes and direct dyes, and since they have anionic property, they easily form a complex with a cationic polymer, and the cationic polymer catches the dye. Dye becomes difficult to redissolve in water. In that respect, the ionene polymer has a higher content of the cationic group in the polymer as compared with the acrylic acid-based quaternary ammonium salt type cationic polymer, so that the ratio of forming a complex with the dye is high, and the hydrophobic group (R ₁ and
Since the content of R ₂ ) is also high, the hydrophobicity of the polymer itself is high,
Therefore, it is presumed that it has excellent water resistance. In addition, since a hydrophobic group and a hydrophilic group (hydroxyl group) are present in the same molecule in a well-balanced manner, a strong hydrogen bonding force works in the molecule and between the molecules, and a Van der Waals force also works between the molecules, and the coloring material is applied to the printing paper. It can be strongly dyed. As a result, the color developability is improved. In addition, there are a hydrophobic group and a hydrophilic group in the same molecule,
It is presumed that, when the water-soluble polymer binder such as polyvinyl alcohol is added, the miscibility with these is improved because the surface activity is imparted due to the balance thereof.

(B) Cationic vinyl polymer The cationic vinyl polymer causes an association by ionic interaction with the dye, and instantaneously separates the ink from the solution phase to contribute to the fixing of the dye. You can The cationic vinyl polymer has the general formula (2):

[Chemical formula 26] The quaternary ammonium salt group represented by and / or the general formula (3):

[Chemical 27] (However, in the general formulas (2) and (3), R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ is an alkyl group having 1 to 8 carbon atoms, aryl An alkyl group or an alicyclic alkyl group, wherein X ⁻ is a counter ion is preferable. The counter ion X ⁻ in the general formulas (2) and (3) is generally a halogen ion, an alkyl sulfate ion, an alkyl or aryl sulfonate ion, an alkyl sulfite ion, or an alkyl phosphate ion. The quaternary ammonium base can be obtained by adding an alkyl halide or the like to an alkylamino group.

(I) Cationic vinyl polymer (A) The cationic vinyl polymer has the general formula (4):

[Chemical 28] Structural unit I represented by the general formula (5):

[Chemical 29] (However, in the general formulas (4) and (5), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an optionally branched carbon atom of 1 to 1.
10 represents an alkylene group, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 to 4 carbon atoms.
8 represents an alkyl group, an arylalkyl group or an alicyclic alkyl group, and X ⁻ represents a counter ion. )
II, general formula (6):

[Chemical 30] Structural unit III represented by, and the general formula (7):

[Chemical 31] (However, in the general formulas (6) and (7), R ₃ and R ₅ are the same as those in the general formula (4), and X ⁻ represents a counter ion.) Of at least one selected from the above (cationic vinyl polymer (A)) is more preferable. By using the cationic vinyl polymer (A), the color developability is improved.

The cationic vinyl polymer (A) has the general formula
(9):

[Chemical 32] And a quaternary ammonium salt group-containing acrylic monomer represented by the general formula (10):

[Chemical 33] (However, in the general formulas (9) and (10), R ₆ represents hydrogen or a methyl group, and R ₇ is an optionally branched carbon atom 1
~ 10 alkylene groups, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 carbon atom each.
8 alkyl group, an aryl group or an alicyclic alkyl group, X ^- represents a counter ion. ) A quaternary ammonium salt group-containing acrylic monomer represented by the general formula (11) and the general formula (11):

[Chemical 34] (However, in the general formula (11), R₃And R_FiveIs the general formula (9)
Is similar to X^-Represents a counter ion. ) Zia
At least selected from the group consisting of rill ammonium salts
Obtained by polymerizing one kind. General formula (9) ~
Counterion X in (11) ^-Is generally a halogen ion,
Killsulfate ion, alkyl or aryl sulfonic acid
Ion, alkyl sulfite ion, or alkyl phosphate
Is on.

The quaternary ammonium salt group-containing acrylic monomer represented by the general formulas (9) and (10) is obtained by quaternizing an amine-containing (meth) acrylate and (meth) acrylamide with a quaternizing agent. Is. Examples of the (meth) acrylate and (meth) acrylamide having an amine include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate and dipropylaminoethyl. (Meth) acrylate, dibutylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylamide, diethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide, dimethylaminobutyl (meth) acrylamide, dipropylaminoethyl (meth ) Acrylamide, dibutylaminoethyl (meth) acrylamide and the like.

Examples of the quaternizing agent include alkyl halides such as methyl chloride, ethyl chloride, methyl bromide and ethyl iodide;
Benzyl halides such as alkylbenzyl chloride and benzyl chloride; dialkyl sulfates such as dimethylsulfate, diethylsulfate and dipropylsulfate; sulfonates such as methyl p-toluenesulfonate and methyl benzenesulfonate; sulfites such as dimethyl sulfite; trimethyl. Examples include alkyl phosphates such as phosphates.

From the standpoint of ease of production and economy, R ₇ preferably has 2 or 3 carbon atoms. From the viewpoint of water dispersibility during preparation of the sizing agent, R ₆ is preferably hydrogen, and R ₃ , R ₄ and R ₅ are preferably methyl groups or ethyl groups. In particular, the following formula (12):

[Chemical 35] And N, N-dimethylaminoethyl acrylate / methyl chloride quaternary compound represented by the following formula (13):

[Chemical 36] N, N-dimethylaminopropylacrylamide methyl chloride quaternary compound represented by

The diallylammonium salt represented by the general formula (11) can be obtained by quaternizing diallylalkylamine with a quaternizing agent similar to the above or by quaternizing dialkylallylamine with allyl chloride. . Examples of the amine having two allyl groups include diallylmethylamine.

The diallylammonium salt is particularly represented by the following formula (14):

[Chemical 37] Preferred is diallyldimethylammonium chloride.

The cationic vinyl polymer (A) has the general formula (9)
And at least one selected from the group consisting of a quaternary ammonium salt group-containing acrylic monomer represented by (10) and a diallylammonium salt represented by the general formula (11) in water, an organic solvent or a mixed solvent thereof. Dissolve evenly, 50
It can be obtained by carrying out a polymerization or copolymerization reaction at -80 ° C for 4 to 10 hours. When an organic solvent is used, hydrophilic organic solvents such as methanol, ethanol, isopropanol, n-butanol, acetone and methyl ethyl ketone are preferable, and these may be used as a mixture with water. After completion of the reaction, water is added as necessary to adjust the viscosity, and the organic solvent is distilled off if necessary to obtain a uniform aqueous solution of the cationic vinyl polymer (A).

The cationic vinyl polymer (A) is a main chain hydrocarbon derived from a quaternary ammonium salt group-containing acrylic monomer and / or diallylammonium salt (collectively referred to as "cationic vinyl monomer"). Chain and fourth
It is composed of a quaternary ammonium base, that is, a quaternized cation portion (hereinafter, simply referred to as “cation portion”). Since the cation portion contributes to the fixing of the dye, the coloring property is improved by using it together with the ionene polymer. Further, the main chain hydrocarbon chain is formed by the polymerization of vinyl groups and / or substituted vinyl groups in the cationic vinyl monomer, and has a size effect, that is, a water resistance effect due to its hydrophobicity.

The cationic vinyl polymer (A) has a number average molecular weight (Mn) of 5 × 10 ^{3 to} 3 × 10 ⁵ in order to provide an ink jet print having good color development, print density and water resistance. Is preferred. When the Mn is less than 5 × 10 ³ , the fixability of the cationic vinyl polymer (A) to the pulp is deteriorated, while when Mn exceeds 3 × 10 ⁵ , the cationic vinyl polymer at the time of preparing the sizing agent ( The solubility of A) is insufficient. More preferable Mn is 1 × 10 ⁴ to 1 × 10 ⁵ .

If necessary, the cationic vinyl polymer (A) may contain a fourth vinyl compound within a range not impairing the effects of the present invention.
A polymerizable monomer other than the primary ammonium base-containing acrylic monomer, diallyl ammonium salt and polyoxyalkylene group-containing acrylic monomer may be copolymerized. Such polymerizable monomers include vinylpyrrolidone, vinyl acetate, styrene, methyl vinyl ether,
Polymerizable silicone, (meth) acrylic acid, (meth) acrylamide, dimethylacrylamide, acrylonitrile, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hydroxyethyl (meth) acrylate, ( Examples include monomers such as hydroxypropyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, glycidyl (meth) acrylate, and phenoxyethyl (meth) acrylate. Of these, those containing a cationic moiety in the molecule such as quaternized vinylpyrrolidone are preferable. The polymerizable cationic monomer is not particularly limited as long as it is a cationic monomer other than the cationic compound that characterizes the present invention, and it only plays an auxiliary role.

(Ii) Cationic vinyl polymer (B) The cationic vinyl polymer has the general formula (4):

[Chemical 38] Structural unit I represented by the general formula (5):

[Chemical Formula 39] (However, in the general formulas (4) and (5), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an optionally branched carbon atom of 1 to 1.
10 represents an alkylene group, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 to 4 carbon atoms.
8 represents an alkyl group, an arylalkyl group or an alicyclic alkyl group, and X ⁻ represents a counter ion. )
II, general formula (6):

[Chemical 40] Structural unit III represented by, and the general formula (7):

[Chemical 41] (However, in the general formulas (6) and (7), R ₃ and R ₅ are the same as those in the general formula (4), and X ⁻ represents a counter ion.) And at least one selected from the general formula (8):

[Chemical 42] (However, R ₈ represents hydrogen or a methyl group, R ₉ is an optionally branched alkylene group having 4 or less carbon atoms, R ₁₀ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and n is 1 to 30. It is composed of a structural unit V represented by
To at least one selected from the group consisting of IV): (constituent unit V) in a weight ratio of 30 to 99:70 to 1 and a number average molecular weight of 5 × 10 ^{3 to} 3 × 10 ⁵ (Cationic vinyl polymer (B)) can also be used.

The cationic vinyl polymer (B) is a quaternary ammonium salt group-containing acrylic monomer represented by the general formulas (9) and (10) and a diallyl ammonium salt represented by the general formula (11). At least one selected from the group consisting of (hereinafter referred to as vinyl monomer (I)) and the general formula (1
Five):

[Chemical 43] (However, R ₈ represents hydrogen or a methyl group, R ₉ is an optionally branched alkylene group having 4 or less carbon atoms, R ₁₀ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and n is 1 to 30. It is obtained by copolymerizing with a polyoxyalkylene group-containing acrylic monomer (hereinafter, referred to as vinyl monomer (II)) represented by an integer.

In order for the cationic vinyl polymer (B) to fully exhibit its performance, the vinyl monomer (I) and the vinyl monomer
The mixing ratio with (II) is 100% by weight of the total of both,
The proportion of the vinyl monomer (I) is preferably 30 to 99% by weight, more preferably 50 to 95% by weight.

The cationic vinyl polymer (B) is produced by copolymerizing a mixture of the vinyl monomer (I) and the vinyl monomer (II) by a solution polymerization method. The vinyl monomer (I) and the vinyl monomer (II) are uniformly dissolved in water, an organic solvent or a mixed solvent thereof, and subjected to a copolymerization reaction at 50 to 80 ° C for 4 to 10 hours. Methanol when using an organic solvent,
Hydrophilic organic solvents such as ethanol, isopropanol, n-butanol, acetone and methyl ethyl ketone are preferable, and these may be used as a mixture with water. After the reaction is completed, water is added as necessary to adjust the viscosity, and the organic solvent is distilled off as necessary to obtain a uniform aqueous solution of the cationic vinyl polymer (B). Since it is a copolymerization reaction by the solution polymerization method, the bonding mode of the vinyl monomer (I) and the vinyl monomer (II) is considered to be mainly a random bond.

The above vinyl monomer (I) and vinyl monomer (II)
Copolymer consisting of and cationic vinyl polymer
(B) is a main chain hydrocarbon chain derived from both acrylic monomers, an oxycarbonyl group, a polyether group, and a quaternary ammonium salt group, that is, a quaternized cation moiety (hereinafter simply referred to as "cation moiety"). Consists of. The polyether group contributes to the dispersion of the dye, and the cation portion contributes to the fixing of the dye. That is, the dye contained in the ink is promptly absorbed and dispersed, and then associates with the cation portion in the printing paper by ionic interaction and is instantaneously separated from the solution phase, so that the fixing property of the dye is improved. . Therefore, when used together with the ionene polymer, the color developability is improved. The hydrocarbon chain of the main chain is formed by polymerization of vinyl groups and / or substituted vinyl groups in both acrylic monomers, and also has a size effect, that is, a water resistance effect due to its hydrophobicity.

The cationic vinyl polymer (B) is particularly excellent in color developability. The reason for this is that when the cation portion and the dye are ionically bonded, the polyether group becomes a steric hindrance, making it difficult to form a large polymer complex, and the aggregated state of the dye does not change (insolubilization). It is considered that this is because the absorption spectrum of light does not change, and therefore the image does not greatly differ from the hue originally possessed by the dye, or the image becomes dark and sunk and inferior in sharpness. It is considered that the good coordination of the cation moiety and the polyether group by random copolymerization also contributes to this. Only by mixing homopolymers obtained by separately polymerizing the vinyl monomer (I) and the vinyl monomer (II), a portion in which the same structural unit is unevenly distributed, and the dispersibility of the dye may be deteriorated. is there.

The cationic vinyl polymer (B) has a number average molecular weight (Mn) of 5 × 10 ^{3 to} 3 × 10 ⁵ in order to provide an ink jet printed matter having good color developability, print density and water resistance. Is preferred. When the Mn is less than 5 × 10 ³ , the fixability of the cationic vinyl polymer (B) to the pulp is deteriorated, while when Mn exceeds 3 × 10 ⁵ , the cationic vinyl polymer ( The solubility of B) is insufficient. More preferable Mn is 2 × 10 ⁴ to 2 × 10 ⁵ .

If necessary, the cationic vinyl polymer (B) may be added with a fourth vinyl compound within a range not impairing the effects of the present invention.
A polymerizable monomer other than the primary ammonium base-containing acrylic monomer, diallyl ammonium salt and polyoxyalkylene group-containing acrylic monomer may be copolymerized. Examples of such a polymerizable monomer include the same compounds as those described above which can be copolymerized with the cationic vinyl polymer (A), but those containing a cationic moiety in the molecule are preferable. The polymerizable cationic monomer is
The present invention is not particularly limited as long as it is a cationic monomer other than the cationic monomer that characterizes the present invention, and it only plays an auxiliary role.

(C) Blending ratio The blending ratio of the water-soluble modified polyamine resin and the cationic vinyl polymer is 100% by weight of the total of the water-soluble modified polyamine resin and the cationic vinyl polymer. The content of the resin is preferably 5 to 95% by weight, more preferably 10 to 70% by weight. By setting the content of the water-soluble modified polyamine resin to 5 to 95% by weight, the water-soluble modified polyamine resin and the cationic vinyl polymer can exert a synergistic effect without losing their mutual advantages.

(2) In order to further improve the water-soluble soybean polysaccharide color developability, print density and water resistance,
It is preferable to add a water-soluble soybean polysaccharide to the sizing agent of the present invention. The water-soluble soybean polysaccharide is a water-soluble polysaccharide extracted and purified from soybean, and is composed of various kinds of sugars such as galactose, arabinose, galacturonic acid, rhamnose, xylose, fucose and glucose. It is presumed that the water-soluble soybean polysaccharide has a structure in which galactan and arabinan are bound to a rhamnogalacturonic acid chain, and its main chain is negatively charged. Therefore, it is presumed that the water-soluble modified polyamine-based resin and the cation of the cationic vinyl polymer are attracted, and the water-soluble soybean polysaccharide and the water-soluble modified polyamine-based resin and the cationic vinyl polymer are in a pseudo-crosslinked state in the sizing agent. It The water-soluble modified polyamine resin and cationic vinyl polymer penetrate into the paper layer by forming a pseudo-crosslinked product of water-soluble soybean polysaccharide, water-soluble modified polyamine resin and cationic vinyl polymer (cationic polymer). It is considered that the ink-fixing property and color developability due to the water-soluble modified polyamine resin and the cationic vinyl polymer can be improved because they remain in the vicinity of the surface without doing so.

Examples of the water-soluble soybean polysaccharide include "Soyafive-S-DN" (trade name, manufactured by Fuji Oil Co., Ltd.). The water-soluble soybean polysaccharide is preferably added in a ratio of 0.1 to 30 parts by weight with respect to 100 parts by weight of the total of the water-soluble modified polyamine resin and the cationic vinyl polymer, 0.5
More preferably, it is added in a proportion of 5 parts by weight. The water-soluble soybean polysaccharide may be added as it is to the sizing agent of the present invention, or the water-soluble modified polyamine resin and / or the cationic vinyl polymer may be fixed to the water-soluble soybean polysaccharide. When fixing, water-soluble modified polyamine resin and /
Alternatively, it is preferable to graft polymerize the cationic vinyl polymer onto the water-soluble soybean polysaccharide. The graft polymerization is carried out, for example, by adding the vinyl monomer (I) and / or the vinyl monomer (II) and a known polymerization initiator to a water-soluble soybean polysaccharide solution and reacting them.

(3) Aqueous Resin An aqueous resin can be added to the sizing agent of the present invention, if necessary, within a range that does not significantly impair the effects of the present invention. The water-based resin is a water-soluble resin or a water-dispersible resin that can receive a so-called water-based ink and has an affinity for the water-based ink. As the water-soluble resin, modified products of polyvinyl alcohol such as polyvinyl alcohol and anion-modified polyvinyl alcohol, cation-modified polyvinyl alcohol, acetal-modified polyvinyl alcohol and the like; polyurethane; polyvinylpyrrolidone and a copolymer of polyvinylpyrrolidone and vinyl acetate, vinylpyrrolidone and dimethyl. Modified products of polyvinylpyrrolidone such as aminoethyl / methacrylic acid copolymers, quaternized vinylpyrrolidone / dimethylaminoethylmethacrylic acid copolymers, vinylpyrrolidone / methacrylamidopropyltrimethylammonium chloride copolymers; carboxymethylcellulose , Hydroxyethyl cellulose, hydroxypropyl cellulose and other cationized hydroxyethyl cellulose and other cellulose Modified products; polyester, polyacrylic acid (ester), melamine resins and modified products thereof, synthetic resins such as copolymers of polyester and polyurethane; poly (meth) acrylic acid, poly (meth)
Examples thereof include acrylamide and the like, but are not limited thereto. Among these water-soluble resins, at least one selected from the group consisting of polyvinyl alcohol, cation-modified polyvinyl alcohol, acetal-modified polyvinyl alcohol, polyester, polyurethane, and a copolymer of polyester and polyurethane from the viewpoint of color developability and ink absorbability. Is preferably used.

As the water-dispersible resin, polyvinyl acetate,
Ethylene-vinyl acetate copolymer, polystyrene, styrene- (meth) acrylic acid ester copolymer, (meth) acrylic acid ester-based polymer, vinyl acetate- (meth) acrylic acid (ester) copolymer, styrene-butadiene A large number of copolymers, ethylene-propylene copolymers, polyvinyl ethers, silicone-acrylic copolymers, and the like can be listed, but are not limited to these. Further, it may be a crosslinking agent such as methylolated melamine, methylolated urea, methylolated hydroxypropylene urea, or isocyanate, or a copolymer containing units such as N-methylol acrylamide and having a self-crosslinking property. It is also possible to use a plurality of these water-based resins at the same time. The aqueous resin is usually added in an amount of 0 to 1000 parts by weight, preferably 10 to 200 parts by weight, based on 100 parts by weight of the total of the water-soluble modified polyamine resin and the cationic vinyl polymer.

(4) Surfactant The surfactant is a component which can be optionally added to the sizing agent of the present invention. As the surfactant, any of an anion activator, a cation activator, an amphoteric activator and a nonionic activator can be used, and the nonionic activator is particularly effective. By adding the surfactant, the water resistance of the image is improved, the image density is increased, and the bleeding is improved.

As the nonionic activator, higher alcohol ethylene oxide adduct, alkylphenol ethylene oxide adduct, fatty acid ethylene oxide adduct, polyhydric alcohol fatty acid ester ethylene oxide adduct, higher aliphatic amine ethylene oxide adduct,
Fatty acid amide ethylene oxide adduct, oil and fat ethylene oxide adduct, polypropylene glycol ethylene oxide adduct, glycerol fatty acid ester,
Examples thereof include fatty acid esters of pentaerythritol, fatty acid esters of sorbitol and sorbitan, fatty acid esters of sucrose, alkyl ethers of polyhydric alcohols, fatty acid amides of alkanolamines and the like.

Examples of the polyhydric alcohols of the above exemplified compounds include, but are not necessarily limited to, glycerol, trimethylolpropane, pentaerythritol, sorbitol and sucrose. Further, as the ethylene oxide adduct, it is also effective to substitute a part of ethylene oxide with alkylene oxide such as propylene oxide or butylene oxide as long as the water solubility can be maintained. The substitution rate is preferably 50% or less. The HLB (hydrophilic-lipophilicity ratio) of the nonionic activator used in the present invention is preferably from 5 to 15, more preferably from 7 to 13.

As such non-ionic activator, commercially available products may be used. For example, Blaunon BR-32, Blaunon BR-35, Blaunon CW-40, Blaunon N-506, Blaunon of Aoki Yushi Kogyo Co., Ltd. N-509, Braunon EL-1509, Braunon L-210 and Braunon P-303, Daiichi Kogyo Seiyaku Co., Ltd.
Neugen EA-120, Neugen EA-80, Neugen ET-135 and Neugen ET-129, Adeka Pluronic L-43, Adeka Pluronic L-44, Adeka Pluronic of Asahi Denka Co., Ltd.
P-75, ADEKA Pluronic P-94 and ADEKA Pluronic
TR-704, Toho Chemical Industry's Pepol B-184, Pepol D
-304 and Pepol BS-184 and the like. The surfactant is usually added in a proportion of 0 to 10 parts by weight, preferably 0.1 to 1.0 parts by weight, based on 100 parts by weight of the total of the water-soluble modified polyamine resin of the present invention and the cationic vinyl polymer. Add in proportion.

(5) Other Ingredients The sizing agent of the present invention contains a water-soluble modified polyamine resin, if necessary, within a range that does not significantly impair the effects of the present invention.
Components other than the cationic vinyl polymer, the aqueous resin, the water-soluble soybean polysaccharide and the surfactant can be added. Other components include alumina powder, silica powder, natural inorganic powder, resin emulsion, pH adjuster, preservative, antioxidant and other additives.

For the purpose of further improving the image storability, a cationic compound other than the above-mentioned cationic vinyl polymer may be further contained within a range not hindering the achievement of the object of the present invention. Such a cationic compound is not particularly limited as long as it contains a cationic moiety in the molecule. In the constitution according to the present invention, the cationic compound other than the cationic compound characterizing the present invention is not an essential component but merely shows an auxiliary role.

(6) Preparation of sizing agent The sizing agent is a water-soluble modified polyamine-based resin and a cationic vinyl polymer, and water-soluble soybean polysaccharide, an aqueous resin, a surfactant, etc., which are added if necessary, in water or the like. Dissolved in a solvent,
It is prepared by dispersing or emulsifying and adjusting to a concentration suitable for sizing. The solid concentration of the sizing agent is 0.5 to 20 wt.
%, Preferably 1 to 10 wt%, particularly preferably 2 to
It is 5 wt%. The preferred viscosity of the sizing agent is 1.5-2000 mP
a ・ s.

[B] Paper used in combination with offset printing / inkjet printing The paper used in combination with offset printing / inkjet printing of the present invention is obtained by impregnating or coating the surface of the base paper with the above sizing agent. It is possible to mix the sizing agent in the paper material in advance and use it as a so-called internally added size, but it is not preferable because the effect cannot be obtained unless a large amount of the sizing agent is used. The sizing agent may be used in combination with a known sizing agent that is usually used in the production of printing paper.

In producing offset / inkjet printing combined paper, first, a cationic vinyl polymer and water-soluble soybean polysaccharide, an aqueous resin, a surfactant, and other additives which are optionally added are treated with water, A coating solution is prepared by dissolving or dispersing in alcohol, polyhydric alcohol or other suitable organic solvent. Then, the obtained coating liquid, size press method, roll coater method, blade coater method,
Air knife coater method, gate roll coater method, bar coater method, spray coating method, gravure coater method,
It is applied to the surface of the substrate by the curtain coater method or the like. The size press method is preferable from the viewpoints of improving printability, suppressing liquid absorption, and improving paper strength. After coating, for example, hot air drying oven,
Drying is performed using a heating drum or the like to obtain the offset printing / inkjet printing combined paper of the present invention.

The base paper is mainly made of chemical pulp represented by LBKP, NBKP and the like, and a filler, and other internal surface sizing agents and papermaking auxiliaries are used as required, and papermaking is carried out by a conventional method. The pulp material to be used may be mechanical pulp or recycled pulp of recycled paper, or may be mainly composed of these.
Examples of the filler include calcium carbonate, kaolin, talc, titanium dioxide and the like.

The above sizing agent is added to the above base paper in terms of solid content weight.
0.1 to 20 g / m ² and so as to coating or impregnation, preferably made to be 0.5 ~5g / m ^2. Coating amount is 0.1g / m ²
If the amount is less than 20%, the effect is insufficient in terms of color developability, ink absorbability and ink fixability, while if it exceeds 20 g / m ² , curling occurs remarkably in a low temperature and low humidity environment.

The offset printing paper size-treated with the above sizing agent is prepared so that the pH of water extraction is 5 to 9, preferably 6 to 8. Water extraction pH is JIS
-The pH of the extract when about 1.0 g of the test piece specified in P-8133 was immersed in 70 ml of distilled water was measured according to JIS-Z-8802.

The combined offset printing / inkjet printing paper of the present invention is mainly composed of a fibrous pulp and a filler containing a sizing agent containing a water-soluble modified polyamine resin having excellent water resistance and a cationic vinyl polymer having high ink affinity. By sizing on plain paper, the water-soluble modified polyamine resin and the cationic vinyl polymer exert a synergistic effect without losing their respective advantages, and even if offset printing and inkjet printing are performed in the same line The image does not get dirty.

[0059]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

(Preparation of paper for combined offset printing / inkjet printing) Preparation Example 1 ( Preparation of ionene polymer) A pressure-resistant autoclave with a stirrer having a capacity of 2 liters was charged with 900 g of 50 wt% dimethylamine aqueous solution and 139 g of ion-exchanged water. Then, the temperature of the aqueous amine solution was cooled to 10 ° C. or lower, and 925 g of epichlorohydrin was added dropwise thereto under stirring in a nitrogen atmosphere for 1.5 hours. After that, the pressure-resistant autoclave is heated in an oil bath, the temperature of the reaction system is raised to 75 to 85 ° C. in 1 hour, and a copolymerization reaction is performed at the same temperature for 5 hours, and then 50 wt% with ion-exchanged water.
Diluting to a concentration gave 1964 g of a slightly yellow aqueous solution. The Mn of the obtained ionene polymer was 2 × 10 ⁴ .

(Preparation of cationic vinyl polymer (B)) A vinyl monomer was placed in a flask equipped with a stirrer and having a volume of 2 liters.
As (I), 250 g of N, N-dimethylaminoethyl methacrylate / methyl chloride quaternary compound (78% by weight aqueous solution),
As vinyl monomer (II), 195 g of methoxy polyethylene glycol methacrylate (Mw = 400) and 3.0 g of azobisisobutyronitrile were added, and 1000 g of methanol was added.
610 g of water was added and stirred at room temperature (22 ° C) to obtain a uniform solution. Next, nitrogen was passed through the solution for 2 hours for deoxidation, and then the flask was heated in an oil bath to carry out a copolymerization reaction for 8 hours while refluxing methanol at a liquid temperature of 65 ° C. After the reaction was completed, the resulting solution of the cationic vinyl polymer (B) was transferred to a 3 liter beaker and 1000 g
Distilled water was added and mixed, and then methanol was distilled off to obtain 2000 g of a colorless and transparent aqueous solution. The solid content of this solution was 19.5% by weight as measured by the drying method (150 ° C).
Met. Mn of the resulting cationic vinyl polymer (B) is
It was 7.1 × 10 ⁴ .

(Production of paper for combined offset printing / inkjet printing) 50 g of the obtained ionene polymer (based on solid content) and 50 g of cationic vinyl polymer (B) (based on solid content) were dissolved in water, A 6 wt% concentration sizing agent was prepared (viscosity: 15 mPa · s). Apply the above sizing agent to a base paper with a basis weight of 70 g / m ² to a size of 3 g / m ² (solid content weight) with a size press machine, dry in an oven at 120 ° C for 5 minutes, and perform offset printing / inkjet printing. Combined paper was made.

Preparation Example 2 ( Preparation of ionene polymer) A pressure-resistant autoclave with a stirrer having a capacity of 2 liters was charged with 900 g of a 50 wt% dimethylamine aqueous solution and 139 g of ion-exchanged water, and the temperature of the amine aqueous solution was adjusted to 10 ° C or lower. After cooling, 925 g of epichlorohydrin is added dropwise thereto under stirring in a nitrogen atmosphere for 1.5 hours. After that, the pressure-resistant autoclave is heated in an oil bath, the temperature of the reaction system is raised to 75 to 85 ° C. in 1 hour, and a copolymerization reaction is performed at the same temperature for 5 hours, and then 50 wt% with ion-exchanged water.
Diluting to a concentration gave 1964 g of a slightly yellow aqueous solution. The Mn of the obtained ionene polymer was 3.0 × 10 ³ .

(Preparation of cationic vinyl polymer (B)) A vinyl monomer was placed in a flask having a stirrer and a volume of 2 liters.
As (I), 250 g of N, N-dimethylaminoethyl methacrylate / methyl chloride quaternary compound (78% by weight aqueous solution),
As vinyl monomer (II), 65 g of methoxytriethylene glycol acrylate and 3.0 g of azobisisobutyronitrile were added, 1000 g of methanol and 610 g of water were added, and the mixture was stirred at room temperature (22 ° C). A homogeneous solution was obtained. Next, nitrogen was passed through the solution for 2 hours for deoxidation, and then the flask was heated in an oil bath to carry out a copolymerization reaction for 8 hours while refluxing methanol at a liquid temperature of 65 ° C.
After the reaction was completed, the obtained solution of the cationic vinyl polymer (B) was transferred to a 3 liter beaker, 1000 g of distilled water was added and mixed, and then methanol was distilled off to obtain 2000 g of a colorless transparent aqueous solution. It was The solid content of this solution was
It was 19.5% by weight when measured at 0 ° C. The Mn of the obtained cationic vinyl polymer (B) was 1.5 × 10 ⁵ .

(Preparation of paper for combined offset printing / inkjet printing) 30 g of the obtained ionene polymer (based on solid content) and 70 g of cationic vinyl polymer (B) (based on solid content) were dissolved in water, A sizing agent having a concentration of 8 wt% was prepared (viscosity: 20 mPa · s). The above sizing agent is applied to a base paper having a basis weight of 70 g / m ² by a size press device so as to have a weight of 5 g / m ² (solid content weight) and dried in an oven at 120 ° C for 5 minutes.
A paper for both offset printing / inkjet printing was prepared.

Preparation Examples 3 to 7 Using the raw materials shown in Table 1, the concentration of the amine aqueous solution and the reaction temperature / time were appropriately adjusted to synthesize each ionene polymer. In addition, according to each raw material and blending ratio shown in Table 1, mixing ratio of methanol and distilled water in the solvent, reaction temperature / hour,
And the amount of catalyst was appropriately adjusted to synthesize each vinyl copolymer. Using each of the obtained ionene polymers and each of the vinyl copolymers, each sizing agent having the composition shown in Table 1 was prepared. Each offset printing / inkjet printing combined paper was produced in the same manner as in Preparation Example 1 except that each of the obtained sizing agents was applied in each coating amount shown in Table 1.

[0067]

[Table 1]

Mn of the ionene polymer, the cationic vinyl polymer (A) and the cationic vinyl polymer (B) produced in Preparation Examples 1 to 7 was determined by GPC measurement (measuring instrument: Tosoh Corporation).
HPLC 8020 manufactured by Co., Ltd.).

(Evaluation of offset printing and ink jet printing) Example 1 The printing paper obtained in Preparation Example 2 was subjected to full-color printing of 10,000 m using an offset printing machine, and then the printing quality, wet strength and The color developability was measured by the following method. The results are shown in Table 2.

(1) Print quality: Evaluation was made by visually observing the solid print portion. Judgment criteria: ◎: The plate is not stained and the print is clear. ○: The plate is stained, but the print is clear. △: The plate is smeared over time and the print is unclear. ×: The plate is stained immediately after printing. The printing is unclear (in the present specification, unless otherwise specified, the "dirt" of the plate in the offset printing refers to a state in which the boundary line of the printed portion is nonuniform.
There are cases where the cationic polymer adhering to the plate or the rotary portion is affected, and the water-absorbing property of the paper is so high that the resilience of water and oil is lost. (2) Wet strength: The behavior of paper absorbing water used during printing was evaluated visually and by touch. Judgment Criteria: ⊚: The strength immediately after absorbing water is sufficient, and no waviness is observed after drying. ◯: The strength immediately after absorbing water is sufficient, but a slight swell is observed after drying. Δ: The strength immediately after water absorption is sufficient, but waviness is observed after drying. X: The strength immediately after water absorption is insufficient and waviness is observed after drying. (3) Color development: The printing color of the picture portion was visually evaluated. Criteria: ◎: Very good. ◯: Good. Δ: Somewhat bad. X: Bad.

The printing paper obtained in Preparation Example 2 was subjected to full-color printing using an inkjet printer (“Color bubble jet printer BJ F900 (dye ink) and BJ F630 (pigment ink)”, manufactured by Canon Inc.). After that, the color development, water resistance, bleeding and fixing properties of the obtained sample were measured by the following methods.

(1) Color developability: It was evaluated by visually observing the color of the solid print portion. Criteria: ◎: Very good. ◯: Good. Δ: Somewhat bad. X: Bad. (2) Water resistance: Immediately after printing, tilt the sample immediately after printing at 45 °,
Of water was dropped with a spoid, and the state after drying was visually evaluated. Criteria: ⊚: No bleeding at all ◯: Slightly dissolved in water, but no bleeding remained on the paper. Δ: Slight bleeding was seen on both sides of the paper. X: Significant bleeding was observed on both sides of the paper. (3) Bleeding: The fineness of the fine line printed portion was visually evaluated. Criteria: ◎: Very good. ◯: Good. Δ: Somewhat bad. X: Bad. (4) Immediately after recording the fixed alphanumeric characters and solid area, the recorded area is 40 g / c.
Rubbing with sillbon paper with a load of m ² , stains on the recording paper,
It was observed whether the recorded part was dropped. Judgment Criteria: ⊚: There was neither stain on the recording paper nor falling off of the recording portion. ◯: The recording paper was slightly stained, but the recording portion did not fall off. Δ: Stain is found around the recording portion of the recording paper, but there is no practical problem. X: Severe stain is seen around the recording portion of the recording paper.

Comparative Example 1 Offset printing was carried out in the same manner as in Example 1 by using a commercially available offset printing paper (having sizing agent containing starch and polyvinyl alcohol as main components) and a commercially available non-coated inkjet printing paper (quality plain paper). The printing and inkjet printing were evaluated. The results are shown in Tables 2 and 3.

[0074]

[Table 2]

As is clear from Table 2, the paper of Example 1 which is the combined offset printing / inkjet printing paper of the present invention has excellent coloring properties in all colors, excellent printing quality and wet strength, and has been used conventionally. It can be said that it has almost the same performance as the commercially available offset printing paper. On the other hand, the print quality of the commercial non-coated inkjet printing paper of Comparative Example 1 was inferior.

[0076]

[Table 3]

Further, as is apparent from Table 3, the paper of Example 1 which is the combined offset printing / inkjet printing paper of the present invention is excellent in color development in all colors, and is also excellent in water resistance, bleeding and fixing property. Was there. On the other hand, the commercial offset printing paper of Comparative Example 1 was inferior except for bleeding, and the commercial non-coated inkjet printing paper was also inferior in water resistance and fixing property.

As described above in detail, the sizing agent containing the water-soluble modified polyamine resin and the cationic vinyl polymer is used to perform sizing on plain paper mainly containing fibrous pulp and filler to perform offset printing. Also, even if inkjet printing is performed in the same line, a printed image does not become dirty, and offset printing / inkjet printing combined paper exhibiting excellent performance can be obtained. The combined offset printing / inkjet printing paper of the present invention can be preferably used for a removable pressure-sensitive postcard, a delivery slip for home delivery, an address label for direct mail, and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toru Soma             3-2-2 Nihonbashihonishicho, Chuo-ku, Tokyo North             Yue Paper Manufacturing Co., Ltd. (72) Inventor Tadashi Asano             5-16-5 Shimbashi, Minato-ku, Tokyo Co., Ltd.             Institute for Space Environment Engineering (72) Inventor Sato Confucius             5-16-5 Shimbashi, Minato-ku, Tokyo Co., Ltd.             Institute for Space Environment Engineering F-term (reference) 2C056 EA04 FC06                 2H086 BA35 BA37 BA41                 4L055 AG71 AG73 AG77 AG89 AH13                       BE08 EA30 FA17 GA09 GA17

Claims (8)

[Claims] 1. A combined offset printing / inkjet printing paper mainly composed of fibrous pulp and filler, which is sized with a sizing agent containing a water-soluble modified polyamine resin and a cationic vinyl polymer. Offset printing / inkjet printing combined paper. 2. The combined offset printing / inkjet printing paper according to claim 1, wherein the water-soluble modified polyamine resin is at least one selected from the group consisting of an aliphatic amine, an alicyclic amine and an aromatic amine. Offset printing / inkjet printing combined paper, which is an ionene polymer composed of a copolymer with epihalohydrin. 3. The offset printing / inkjet printing combined paper according to claim 2, wherein the ionene polymer is represented by the general formula (1): (However, R ₁ and R ₂ independently represent an alkyl group having 1 to 8 carbon atoms which may have a substituent, an arylalkyl group or an alicyclic alkyl group, and m represents an integer of 10 to 1500, X ^-
Represents a counter ion. ) A combined offset printing / inkjet printing paper comprising a structural unit represented by 4. Offset printing according to claims 1 to 3.
In the inkjet printing paper, the cationic vinyl polymer in the sizing agent is represented by the general formula (2): The quaternary ammonium salt group represented by and / or the general formula (3): (However, in the general formulas (2) and (3), R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ is an alkyl group having 1 to 8 carbon atoms, aryl A combined offset printing / inkjet printing paper comprising a quaternary ammonium salt group represented by an alkyl group or an alicyclic alkyl group, and X ⁻ is a counter ion. 5. The combined offset printing / inkjet printing paper according to claim 1, wherein the cationic vinyl polymer in the sizing agent has the general formula (4): Structural unit I represented by the general formula (5): (However, in the general formulas (4) and (5), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an optionally branched carbon atom of 1 to 1.
10 represents an alkylene group, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 to 4 carbon atoms.
8 represents an alkyl group, an arylalkyl group or an alicyclic alkyl group, and X ⁻ represents a counter ion. )
II, general formula (6): The structural unit III represented by and the general formula (7): (However, in the general formulas (6) and (7), R ₃ and R ₅ are the same as those in the general formula (4), and X ⁻ represents a counter ion.) Offset printing / inkjet printing combined paper comprising at least one of the following types. 6. The combined offset printing / inkjet printing paper according to claim 1, wherein the cationic vinyl polymer in the sizing agent has the general formula (4): Structural unit I represented by the general formula (5): (However, in the general formulas (4) and (5), R ₆ represents a hydrogen atom or a methyl group, and R ₇ represents an optionally branched carbon atom of 1 to 1.
10 represents an alkylene group, R ₃ and R ₄ each independently represent an alkyl group having 1 to 4 carbon atoms, and R ₅ has 1 to 4 carbon atoms.
8 represents an alkyl group, an arylalkyl group or an alicyclic alkyl group, and X ⁻ represents a counter ion. )
II, general formula (6): The structural unit III represented by and a general formula (7): (However, in the general formulas (6) and (7), R ₃ and R ₅ are the same as those in the general formula (4), and X ⁻ represents a counter ion.) And at least one selected from the general formula (8): (However, R ₈ represents hydrogen or a methyl group, R ₉ is an optionally branched alkylene group having 4 or less carbon atoms, R ₁₀ is hydrogen or an alkyl group having 1 to 8 carbon atoms, and n is 1 to 30. It is composed of a structural unit V represented by
To at least one selected from the group consisting of IV): (constituent unit V) in a weight ratio of 30 to 99:70 to 1 and a number average molecular weight of 5 × 10 ^{3 to} 3 × 10 ⁵ Offset printing / inkjet printing combined paper. 7. The combined offset printing / inkjet printing paper according to claim 1, wherein the total amount of the water-soluble modified polyamine resin and the cationic vinyl polymer in the sizing agent is 100% by weight. The content of the water-soluble modified polyamine resin is 5 to 95% by weight as a combined offset printing / inkjet printing paper. 8. The combined offset printing / inkjet printing paper according to any one of claims 1 to 7, wherein the sizing agent contains a water-soluble soybean polysaccharide.