JPS61134290A - Ink jet recording paper - Google Patents

Abstract

PURPOSE:To provide paper for ink jet recording which forms a recorded image having high resolution and high water-proofness by containing modified polyvinyl alcohol (abbreviated as PVA) having the siryl group in paper base material. CONSTITUTION:As a means to contain modified PVA containing the siryl group in paper for ink jet recording, a method to apply or impregnate said PVA on the surface of paper for ink jet recoding by spray or size pess, a method to mix the PVA into coating paint and apply the mixture to paper for ink jet printing with an applying apparatus when manufacturing coated-type paper for ink jet recording or a method to apply the PVA internally to the paper when manuacturing it are available. Normally the dosage of modified PVA containing the silyl group or modified PVA containing the siryl group and cationic group concurently or a mixture of modified PVA containing the silyl gruop and modified PVA containing the cationic group to paper for ink jet recording is 0.01-10g/m<2>.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Application Field The present invention relates to paper for inkjet recording, and particularly to paper for inkjet recording that forms recorded images with high resolution and high water resistance.

B. Conventional technology The inkjet recording method is being applied to 7-axis printers, various printers, etc. due to its low noise, ease of colorization, and high-speed recording. . 2. Description of the Related Art Conventionally, an ordinary rim has been used as a recording material used in an inkjet recording method. but,
As the performance of inkjet recording machines improves, such as faster recording speeds and multicolor recording, more advanced properties are required for inkjet recording paper. First, the absorption speed of the ink is high; second, the diameter of the ink dots must not become larger than necessary; and third, since the ink used in the inkjet recording method is water-soluble, the water resistance of the recorded image is low. This includes improving deficiencies.

Although extensive research has been carried out to meet these requirements, in general, ink dots with good ink absorption tend to spread easily, and the water resistance of recorded images is still far from the practical level requirements. The current situation is that this is not possible.

C1 Problems to be Solved by the Present Invention The purpose of the present invention is to provide paper for inkjet recording that satisfies the above requirements and forms recorded images with particularly high resolution and excellent water resistance. It is in.

A means for solving the D0 problem, that is, the present invention, contains modified polyvinyl alcohol having a silyl group (hereinafter, polyvinyl alcohol is abbreviated as PVA) in the paper base material and/or the coating layer. The present invention relates to an inkjet recording paper characterized by:

The modified PVA containing a silyl group used in the present invention may be any one containing a silyl group, but the silyl group may be an alkoxyl group, an acyloxyl group, a silanol group which is a hydrolyzate thereof, or a salt thereof. Those having a reactive substituent are particularly preferably used.

Methods for producing such modified PVA include: (1) saponifying a copolymer of a vinyl ester and an olefinically unsaturated monomer containing a silyl group; (2) polymerizing a vinyl ester in the presence of a mercaptan having a silyl group; A method of saponifying the obtained polyvinyl ester having a silyl group at its terminal may be mentioned. Vinyl esters used in the above method include vinyl acetate, vinyl propionate, vinyl formate, etc., but vinyl acetate is preferred from an economical standpoint.

Examples of the silyl group-containing olefinically unsaturated monomer used in the above method (1) include vinylsilanes represented by the following formula (1) and (meth)acrylamido-alkylsilanes represented by (II).

1m CH2=CH-(CH2)n-8i-(R2)3-rn
(1) R4R1 CHx= CR3-CN -R'-S i -(R")
3-m (■) [Here, n is 0 to 4, m is 0
~2, R1 is an argyl group having 1 to 5 carbon atoms (methyl, ethyl, etc.), R'' is an alkoxyl group or acyloxyl group having 1 to 40 carbon atoms (here, the alkoxyl group or acyloxyl group is an oxygen-containing substituent) may have.

), R3 is a hydrogen atom or a methyl group, R4 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R5 is an alkylene group having 1 to 5 carbon atoms or a divalent group in which chain carbon atoms are bonded to each other by oxygen or nitrogen. of organic residual funds respectively. In addition, when two R1s exist in the same monomer, R1 may be the same or different, and two or more R2s may exist in the same monomer. ,
R2 may be the same or different. ] Specific examples of vinylsilanes represented by formula (1) include vinyltrimethodisilane, vinyltriethoxysilane, vinyltris-(β-methoxyethoxy)silane, vinyltriacetoxysilane, allyltrimethoxysilane, allyltriacetoxine 2 vinylmethyldimethoxysilane, vinyldimethylmethoxysilane, vinylmethyljethoxysilane, disilane in vinyldimethyleth, vinylmethyldiacetoxysilane, vinyldimethylacetoxysilane, vinylisobutyldimethoxysilane, vinyltriisopropoxysilane, disilane in vinyltrypto, vinyltrihexyloxysilane,
Vinylmeth+silane, vinyldimethoxyoctyloxysilane, vinylmethoxydioctyloxysilane, vinyltriacetoxysilane, vinylmethoxydilauryloxysilane, vinyldimethoxylauryloxysilane, vinylmethoxydioleyloxysilane, vinyldimethoxyoley Roxysilane, and also the general formula %) (where R'' and m are the same as above, and X represents 1 to 20)
Examples include polyethylene glycolized vinylsilane represented by:

Further, specific examples of the (meth)acrylamide-alkylsilane represented by formula (U) include 3-(meth)acrylamide-propyltrimethoxysilane%3-(meth)acrylamide-propyltriethoxysilane, 3-(meth)acrylamide-propyltriethoxysilane,
-(meth)acrylamide-propyltri(β-methoxyethoxy)silane, 2-(meth)acrylamide-2
-Methylpropyltrimethoxysilane, 2-(meth)acrylamido 2-methylethyltrimethoxysilane,
N-(2-(meth)acrylamido-ethyl)-aminopropyltrimethoxysilane, 3-(meth)acrylamido-propyltriacetoxysilane, 2-(meth)acrylamide-ethyltrimethoxysilane, 1-(meth)acrylamide- Methyltrimethoxysilane, 3-(
meth)acrylamido-propylmethyldimethoxysilane, 3-(meth)acrylamido-propyldimethylmethoxysilane, 3-(N-methyl-(meth)acrylamido)-propyltrimethoxysilane, 3-((meth)
Examples include acrylamide-methoxy)-propyltrimethoxysilane.

Further, as the mercaptan having a silyl group used in the method (1) above, 3-(trimethoxysilyl)-propylmercaptan, 3-(triethoxysilyl)-propylmercaptan, etc. can be used.

The polymerization in the method (1) or (2) above can be carried out by a known method using a radical initiator in bulk or in a solution of a lower alcohol such as methanol.

In addition, during the polymerization in the above method, in addition to the above-mentioned components, a monomer having a cationic group is present, and after copolymerizing the monomer, the copolymer is saponified to obtain silyl groups and cations. Modified PVA which simultaneously has a functional group is also useful for the purposes of the present invention. Cationic group-containing t-i used in this method
For example, N-(1,1-pmethyl-3-dimethylaminepropyl)(meth)acrylamide, N-(1
゜1-dimethyl-3-dimethylaminobutyl) (meth)
Acrylamide, N-(1-methyl-1,3-diphenyl-3-diethylaminopropyl)(meth)acrylamide, N-(3-dimethylaminopropyl)(meth)acrylamide, N-(2-dimethylaminoethyl)(meth) ) acrylamide, N-(4-dimethylaminobutyl)(meth)acrylamide, N-vinylimidazole,
2-Methyl-N-vinylimidazole, vinyl-3-dimethylaminopropyl ether, vinyl-2-dimethylaminoethyl ether, vinyl-4-dimethylaminobutyl ether, improbenyl-3-dimethylamine propyl ether, impropenyl-2-dimethyl Aminoethyl ether, allyl-3-dimethylaminopropyl ether, allyl-2-dimethylaminoethyl ether, allyl-4-dimethylaminobutyl ether, allyldimethylamine, methalyldimethylamine, 3-butene dimethylamine and halogenated /L/l
? In particular, monomers quaternized with methyl chloride or ethyl chloride or a quaternizing agent such as dimethyl sulfate or methyl p-toluenesulfonate, dimethyldiallylammonium chloride, diethyldiallylammonium chloride, and the like can be mentioned.

Modified PV containing silyl group used in the present invention
The content of silyl groups in A, the degree of saponification, or the degree of polymerization are appropriately selected depending on the purpose and are not particularly limited. The effect of the silyl group is exhibited even in a relatively small content, and the monomer unit containing the silyl group is usually selected from a range of 0.01 to 10 mol, preferably 0.1 to 2.5 mol. The content of the cationic group in the modified PVA containing both a silyl group and a cationic group is selected from the range of 0.01 to 10 mol, preferably 0.05 to 5 mol.

The degree of saponification of vinyl ester units is usually 50 to 10.
It is selected from the range of 0 molar, preferably 60 to 100 molar. Further, the degree of polymerization of the modified PVA is not particularly limited, but is usually 50 to 3000, preferably 100 to 250.
Selected from a range of 0.

In addition, in the present invention, the above-mentioned silyl group-containing modified PVA
Alternatively, in addition to modified PVA containing both a silyl group and a cationic group, a mixture of a modified PVA containing a silyl group and a modified PVA containing a cationic group is also effective for the purpose of the present invention.

The cationic group-containing modified PVA used in this case may be one having an amine or ammonium group as a cationic group, such as a copolymer of the above-mentioned cationic group-containing monomer and vinyl ester. Those obtained by saponifying are preferably used.

The content of cationic groups in the above-mentioned cationic group-containing modified PVA is selected from the range of 0.01 to 10 mol, preferably 0.05 to 5 mol, as monomer units having cationic groups. The degree of saponification of the vinyl ester unit is preferably selected from the range of 50 to 100 mol, preferably 60 to 100 mol. Furthermore, the degree of polymerization of the modified PVA is usually selected from the range of 50 to 3,000, preferably 100 to 2,500. In the present invention, when using a mixture of silyl group-containing modified PVA and cationic group-containing modified PVA, the weight ratio of the former/latter is preferably 9515 to 5/95, more preferably 90/10 to 40/60. More preferably, it is selected from the range.

In the present invention, the method for incorporating silyl group-containing modified PVA into inkjet recording paper includes, for example, applying or impregnating the surface of inkjet recording paper made by a known method by spraying or size press, or When producing a coated paper type of inkjet recording paper, the coating material is mixed with the coating material and coated with a coating machine such as a blade, air knife, roll coater, etc.; Examples include a method of adding it internally during paper making.

Silyl group-containing modified PV in paper for inkjet recording
The amount added of A or modified PVA containing a silyl group and a cationic group at the same time, or a mixture of a silyl group-containing modified PVA and a cationic group-containing modified PVA is usually 0.
．． 01-10 f/rrl, preferably 0.05-5
f/male is used. When the amount added is less than 0.0 IP/-, the effect of improving resolution and water resistance is low, and 10? /n1
If it exceeds ``, the ink absorption speed tends to decrease, which is not preferable.

As mentioned above, the silyl group-containing modified PVA used in the present invention can be applied to all types of inkjet recording papers, especially Merck, kaolin, calcium carbonate, non-colloidal silica powder, and finely powdered urea-formalin resin fillers. Recording paper with various fillers such as, or recording paper with a coating layer of white pigment such as non-colloidal silica powder, acid clay, clay, Merck, calcium carbonate, diatomaceous earth, titanium oxide, barium sulfate, etc. By applying the method to the present invention, it is possible to obtain paper for inkjet recording that has high resolution and can form highly water-resistant recorded images.

Similarly, when incorporating silyl group-containing modified PV, A into paper for inkjet recording, water-soluble resins such as polyacrylamide, starch, casein, gum arabic, carboxymethyl cellulose, methyl cellulose, PVA, sodium polyacrylate, synthetic rubber, etc. Pot 1 additives such as synthetic resin latex, dispersed fluorescent dye, F4-1 regulator, antifoaming agent, lubricant, preservative, surfactant, etc. can also be used in combination.

The reason why the inkjet recording paper of the present invention is able to form recorded images with high resolution and water resistance is not fully elucidated, but it is presumed as follows. .

That is, the silyl group in the silyl group-containing modified PVA used in the present invention has high reactivity with the filler or pigment present in paper for inkjet recording, and even a small amount can provide high strength and high strength to the filler or pigment. Because it exhibits water-resistant binder ability, the ink absorption performance is not hindered by the coating of the filler or pigment surface, which is the case with ordinary binders, and the ink absorption performance of the filler or pigment is maintained at a high level, and the ink absorption performance of the filler or pigment is maintained at a high level. It is presumed that since the absorbent ink can be sufficiently occluded therein, images with high absorbency, high resolution, and water resistance can be formed.

In addition, in the case where the silyl group-containing modified PVA also contains a cationic group, or in the case of a mixture of the silyl group-containing modified PVA and the cationic group-containing modified PVA, in addition to the above-mentioned effects, the cationic group and the inkjet recording It is presumed that resolution and water resistance are further improved by the formation of a water-resistant conjugate through chemical reaction with anionic inks commonly used in the system.

The present invention will be explained in more detail with reference to Examples below.
The invention is not limited thereby. In addition, the key words "chi" and "bu" unless otherwise specified in the implementation row.
represents the weight standard.

Example 1 A modified PVA having a silyl group in the molecule contains 0.5 mole of vinylsilane units obtained by saponifying a copolymer of vinyl acetate and vinyltrimethoxysilane, and the degree of saponification of the vinyl acetate units is 98. A coating composition was prepared based on the following composition using modified PVA having a molar ratio of .550 and a degree of polymerization of 550.

Non-colloidal silica powder 100 parts Silyl group-containing modified PVA 20 parts Water
500 copies On the other hand, general high-quality paper (basis weight 65 P/I!1'') with a sizing degree of 30 seconds based on JIS P8122 was used as the base paper, and the above coating composition was applied on this base paper in a dry coating amount. It was coated with a blade coater to give 202/♂ and dried to obtain paper for inkjet recording.

Color inkjet recording was performed on this recording paper using the following four color inks, and the recording characteristics were evaluated.

Yellow ink (composition) C, i. Acid Yellow 23 2 parts diethylene glycol 30 parts water
70 parts Degenta ink (composition) (1, Acid Red 32 2 parts diethylene glycol 30 parts water
70 parts cyan ink (
Composition) C, j Direct Blue 86 2 parts diethylene glycol 30 parts water
70 parts Black ink (composition) (,j Direct Black 19 2 parts diethylene glycol 30 parts water
Table 1 shows the evaluation results of the recording characteristics of the 70-copy recording paper.

The degree of smearing was determined by measuring the diameter of a printed dot using a stereomicroscope and indicating how many times larger it was than the diameter of an ink droplet. Water resistance was determined by immersing the recording paper in running water for 3 hours and comparing the optical density (OD) measured using a Macbeth densitometer after immersion with the (JL) value before immersion.

Examples 2 to 7 Modified P having a silyl group in the molecule used in Example 1
The same procedure as in Example 1 was carried out except that the following modified PVA was used instead of VA.・The results are shown in Table 1.

Modified 1'VA used in Example 2: Contains 0.2 molar vinylsilane units obtained by saponifying a copolymer of vinyl acetate and vinyltriethoxysilane, and the saponification degree of vinyl acetate units is 98.5. Modified PV with molecular weight and degree of polymerization of 1750
A0 Modified PVA used in Example 3: Modified PVA obtained by saponifying a polymer having a silyl group at the end obtained by polymerizing vinyl acetate in the presence of trimethoxysilylpropyl mercaptan.
Modified PV with a VA content of 1 mol of silyl group units, 98.5 mol of saponified vinyl acetate units, and a degree of polymerization of 100.
A0 Modified PVA used in Example 4: 0.5 mol of vinylsilane units obtained by saponifying a copolymer of vinyl acetate, vinyltrimethoxysilane, and trimethyl-3-(1-acrylamidopropyl) ammonium chloride. , containing 2 molar monomer units having a cationic group,
Saponification degree of vinyl acetate unit: 98.5 molar ratio, polymerization degree: 50
Modified PVA used in Example 5: Copolymer of vinyl acetate with vinyltris-(β-methoxyethoxy)silane and trimethyl-3-(L-acrylamide-1°1-dimethylglobyl)ammonium chloride. Contains 0.2 mol of vinylsilane units obtained by saponifying silane, 1 mol of monomer units having a cationic group, saponification degree of vinyl acetate units is 88 mol%, polymerization is 12000 (DH-based PVA
0 Modified PVA used in Example 6: Obtained by saponifying 15 parts of the silyl group-containing modified PVA used in Example 2 and a copolymer of vinyl acetate and trimethyl-a-(1-acrylamidopropyl) ammonium chloride. , a mixture with 5 parts of cationic group-containing modified PVA having a content of cationic group-containing monomer units of 1 molar, a saponification degree of vinyl acetate units of 98.5 molar, and a polymerization degree of 1750.

Modified PVA used in Example 7: An equally valuable compound of the silyl group-containing modified PVA used in Example 6 and the cationic group-containing modified PVA.

Example 8 The 4 aqueous solution of silyl group-containing modified PVA used in Example 1 was applied to general paper with a size degree of 10 seconds (basis weight 6 sy/rr?) using a size press so that the dry weight would be 12 ~ was applied to obtain recording paper. Example 1
It was evaluated in the same manner. The results are shown in Table 1.

Example 9 The same procedure as Example 8 was carried out except that the modified PVA used in Example 5 was used instead of the modified PVA used in Example 8. The results are shown in Table 1.

Comparative Example 1 Silyl group-containing modified PVAK used in Example 1
The same procedure as in Example 1 was carried out except that VA (/yinated g 98.5, degree of polymerization 1750) was used. The results are shown in Table 1.

Comparative Example 2 20 parts of modified PVA used in Example 1 and 50 parts of water
The same procedure as in Example 1 was carried out except that 150 parts of the modified PvA and 1000 parts of water were used instead of 0 parts (in this case, the amount added to the silyl group-containing modified PVA0 paper was 12 P/rII
It becomes l. ) The obtained inkjet recording paper had a low ink absorption speed.

Comparative example 3

Claims (2)

[Claims] (1) A paper for inkjet recording, characterized in that it contains modified polyvinyl alcohol having a silyl group in the paper and/or in the coating layer. (2) Contains a mixture of modified polyvinyl alcohol having a silyl group and modified polyvinyl alcohol having a cationic group, or modified polyvinyl alcohol having both a silyl group and a cationic group in the paper and/or coating layer. An inkjet recording paper characterized by: