JPH11124793A - Surface coating materials for papers - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a surface coating materials capable of improving water resistance.resistance to light of color printed matters printed with an ink-jet printer by coating on papers for ink-jet printing. SOLUTION: This surface coating materials for papers consist of a copolymer or polymer composition containing acryloyloxyethyldimethylbenzylammonium chloride unit and acrylic acid unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface coating agent for paper, and more particularly to a surface coating agent for ink jet recording paper.

[0002]

2. Description of the Related Art Ink jet is a non-contact type recording system, has a low noise level, is capable of high-speed recording, and can be easily printed in color.
In terms of recording materials, general printing paper,
It can print on paper, PPC paper, medium paper, and even plastic films.

[0003] Currently, special papers are commercially available to improve the suitability for printing by inkjet. The use of this printing paper improves the water resistance, light resistance, and the sharpness of printing, especially during color printing, so that papermakers and printer manufacturers are focusing on the development of specialty paper. The reason why cationic polymer is generally included in a part of the coating agent in this special paper is because the anionic water-soluble dye is incorporated in the inkjet ink, so that the fixing action of the cationic polymer is Because they use it.

[0004] However, due to the high price of this special paper, it is expected that its spread will be limited and it will be difficult to become a wide-ranging business. For this reason, each company has shifted the weight of R & D to so-called dual paper or co-paper (hereinafter referred to as co-paper), which can be used at almost the same cost as PPC paper. Needless to say, ink jet printing suitability is also required for the co-paper, but a performance compromise is taken into account in comparison with the special paper in terms of usage cost, application, and the like. In short, it depends on the development concept and sales strategy of each company to determine the level of performance for both co-paper manufacturing costs and specialty papers.

At present, the most problematic points regarding co-paper are so-called feathering and water resistance. Ink jet inks are water-based inks that penetrate into a paper fiber network by capillary action. Therefore, ink bleeding is a problem that cannot be avoided to some extent. Paper is sized at the time of paper making to prevent bleeding by the aqueous ink, but the sizing of the paper does not work effectively because the inkjet ink contains a substance that reduces the size effect. Since the common paper does not have a silica coating layer applied to the special paper, the surface size, nonion,
Although treatments for preventing feathering have been made with cationic or anionic polymers, they are not sufficient, and effective polymers and surface sizing agents have not yet been developed. Further, a material having good water resistance in which ink flows out by water is desired.

[0006]

As described above, a surface coating agent for effectively preventing feathering and water resistance has not yet been developed for co-paper. The problem to be solved by the present invention is to develop a surface coating agent effective for feathering and water resistance of common paper.

[0007]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies and found that an aqueous solution of a polymer or a polymer composition having both an acryloyloxyethyldimethylbenzylammonium chloride unit and an acrylic acid unit is coated on a paper surface. It has been found that by using the ink as an ink jet printing paper by applying the ink to a conventional paper, the prevention of feathering and the improvement of water resistance, which are problems specific to the paper, are improved as compared with the current commercially available paper.

The first aspect of the present invention is a paper surface coating agent comprising a polymer of a monomer containing acryloyloxyethyldimethylbenzylammonium chloride and acrylic acid.

The invention according to claim 2 of the present invention is the paper surface coating agent according to claim 1, wherein the content of acrylic acid in all monomers is 2 to 10 mol%. is there.

A third aspect of the present invention is a paper surface coating agent characterized by being a mixture of an acryloyloxyethyldimethylbenzylammonium chloride (co) polymer and an acrylic acid (co) polymer.

According to a fourth aspect of the present invention, the mixing ratio of the acryloyloxyethyldimethylbenzylammonium chloride (co) polymer and the acrylic acid (co) polymer is 1: 0.1 to 1: 0.02. 4. The paper surface coating agent according to claim 3, wherein:

According to a fifth aspect of the present invention, there is provided a paper surface coating agent according to any one of the first to fourth aspects of the present invention, which is used as an ink jet printing paper by being applied to the paper surface.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first limitation of the present invention is a paper surface coating composition comprising a polymer of a monomer containing acryloyloxyethyldimethylbenzylammonium chloride and acrylic acid. A second limitation of the present invention is the paper surface coating composition according to claim 1,
It is characterized in that the content of acrylic acid in all monomers is 2 to 10 mol%. A third limitation of the present invention is a paper surface coating agent characterized in that it is a mixture of acryloyloxyethyldimethylbenzylammonium chloride (co) polymer and acrylic acid (co) polymer.
A fourth limitation of the present invention is that, in the paper surface coating agent according to claim 3, the mixing ratio of the acryloyloxyethyldimethylbenzylammonium chloride (co) polymer and the acrylic acid (co) polymer is 1: 0. 1-1: 0.02. A fifth limitation of the present invention is claim 1
The paper surface coating agent according to claim 4 is characterized in that it is used as an inkjet printing paper by being applied to the paper surface.

Hereinafter, the present invention will be described specifically. Acryloyloxyethyl dimethylbenzyl ammonium chloride used in the present invention is obtained by reacting dimethylaminoethyl acrylate with benzyl chloride at room temperature. Acrylic acid is commercially available. Both can be easily mixed and polymerized as an aqueous solution. It is also possible to mix homopolymers separately after obtaining them, or to mix copolymers of both monomers and acrylamide, and to obtain a tertiary copolymer of acryloyloxyethyldimethylbenzylammonium chloride, acrylic acid and acrylamide. A polymer can also be obtained. The polymerization is carried out in an acidic manner at a temperature of 10 ° C. to 100 ° C., preferably 30 ° C. to 80 ° C., by an organic or inorganic peroxide, an azo initiator or an initiator system which forms a redox system with these peroxides. Can do it. If the amount of the acrylic acid unit, which is an anionic group, is less than the range of the present invention, sufficient effects cannot be exerted. If the amount is too large, the ink fixability is poor.

The basic invention of the present invention relates to a surface coating agent for papermaking as a specific application of the above water-soluble polymer, and the product of the present invention relates to other coating agents such as cationic starch and oxidized starch. Water-soluble polymers such as starch and polyvinyl alcohol, and latex, or coating pigments such as colloidal silica, talc, kaolin clay, and calcium carbonate can be used in combination. The addition amount of these coating agents is usually 0.1.
05 to 10 g / m ^2, preferably 0.2 to 5 g / m ² . The base paper for coating is not particularly limited, and can be applied to base papers such as coated base paper of acid paper and neutral paper, newsprint, PPC paper and the like. A water-soluble polymer of the present invention alone or mixed with another coating agent is coated on a coating base paper with a size press, a gate roll coater, a blade coater, a calender, or the like, and the surface is coated. It can be.

The present invention relates to a surface coating agent for papermaking as a specific application of the above water-soluble polymer, and is characterized in that the product of the present invention is coated on the surface of a coated base paper. It is a manufacturing method. The present invention not only improves the printability of the coated base paper as described above, but also combines with an anionic water-soluble ink as an inkjet recording paper to make it water-insoluble, suppresses penetration into the paper, and performs inkjet printing. Maintains a vivid color tone in the expression of the color.

The amount of the surface coating agent of the present invention to be applied to the paper surface should be determined in consideration of the cost depending on the special paper for ink jet and the common paper. In the case of 0.02 to ² g / m ² dedicated paper, the surface coating agent of the present invention is used in combination with a filler and a binder. In the case of co-paper, the surface coating agent is used in combination with starch oxide, polyvinyl alcohol, a surface sizing agent, or the like. The surface coating agent of the present invention is applied alone.

[0018]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, which, however, are not intended to limit the scope of the present invention.

(Synthesis Example-1) 500 ml equipped with a thermometer, a stirrer, a separatory funnel, an N ₂ inlet tube and a condenser
Of a monomer having a composition of 97 mol% of acryloyloxyethyldimethylbenzylammonium chloride and 3 mol% of acrylic acid, and adding ammonium peroxodisulfate to the monomer in an amount of 0.3% with respect to the monomer. % By weight, adjusted to pH 3.5, monomer was equally divided into 8 times in 2 hours from the separating funnel and added to the system, and the temperature was maintained at 60 ° C while stirring the raw material mixture. Then, polymerization was carried out. After completion of the addition of the monomer, the temperature was maintained at 60 ° C., and the reaction was continued for 4 hours. Then, after confirming that the polymerization rate was 99% or more, the viscosity at 25 ° C. was measured to be 5000 CP. This is called Sample-1.

Synthesis Example 2 The same operation as in Synthesis Example 1 was performed except that a 30% aqueous solution of a monomer having a composition of acryloyloxyethyldimethylbenzylammonium chloride 95 mol% and acrylic acid 5 mol% was used. The viscosity at 25 ° C. was 6000 CP. This is called Sample-2.

(Synthesis Example 3) A polymer of a monomer of 100 mol% of acryloyloxyethyldimethylbenzylammonium chloride, a 30% aqueous solution having a viscosity of 5000 CP at 25 ° C. and a molar copolymer of acrylamide / acrylic acid, etc. A polymer composition in which a 30% aqueous solution of a polymer having a viscosity of 5000 CP at 25 ° C. in a weight ratio of 20: 1 is referred to as Sample-3.

(Synthesis Example 4) A polymer of acryloyloxyethyldimethylbenzylammonium chloride monomer of 100 mol%, a 30% aqueous solution having a viscosity of 5000 CP at 25 ° C. and a molar copolymer of acrylamide / acrylic acid, etc. A polymer composition obtained by mixing a polymer having a viscosity of 5000 CP at 25 ° C in a 30% aqueous solution at a weight ratio of 40: 1 is referred to as Sample-4.

(Synthesis Example-5) A polymer of a monomer of acryloyloxyethyldimethylbenzylammonium chloride of 100 mol% and a 30% aqueous solution having a viscosity of 5000 CP at 25 ° C. is referred to as Comparative-1.

(Synthesis Example-6) Methacryloyloxyethyldimethylbenzylammonium chloride 100 mol%
A polymer having a viscosity of 5000 CP at 25 ° C. in a 30% aqueous solution of the monomer of Comparative Example 2 is referred to as Comparative-2.

(Synthesis Example 7) 95 mol% of methacryloyloxyethyldimethylbenzylammonium chloride,
The same operation as in Synthesis Example 1 was carried out except that a 30% aqueous solution of a monomer having a composition of 5 mol% of acrylic acid was used, and the viscosity at 25 ° C. was found to be 5000 CP. This is called comparison-3.

(Synthesis Example-8) Methacryloyloxyethyldimethylbenzylammonium chloride 100 mol%
A polymer having a viscosity of 5000 CP at 25 ° C. in a 30% aqueous solution of a monomer polymer and a polymer having a viscosity of 5000 CP at 25 ° C. in a 30% aqueous solution of an acrylamide / acrylic acid equimolar copolymer in a weight ratio of 40: 1. Is referred to as Comparative-4.

[Examples 1 to 4] Coating liquid [6.8 g of fine powdered silica, PVA117 (manufactured by Kuraray Co., Ltd.) was used as a support, using a high-quality paper having a basis weight of 70 g / m ² and a Steckigt sizing degree of 25 seconds.
2.7 g, 0.5 g of the polymer of this example and 40 g of water
Was mixed with a coating rod at a solid content of 5.0 g / m ² on one side to obtain a coated paper. After color printing of this coated paper, the water resistance and lightfastness of the print were measured as follows. Color printing is provided by Canon Inc.
Solid printing was performed for each color of magenta (M), cyan (C), yellow (Y), and black (BL) using a color bubble jet printer manufactured by BJC600. Table 1 shows the results. (Water resistance) The solid printed image was immersed in running water of 3 liter / min for 10 minutes, and the image density before and after the test was evaluated on a 5-point scale. <Judgment> A: No change B: Color slightly exudes. C: Discoloration is recognized. D: Large discoloration. E: Almost decolorization. (Light fastness) The solid printed image is 24
Irradiation was performed for a period of time, and the image density before and after the irradiation was evaluated in four stages. <Judgment> A: No change B: Slight fading. C: Fading. D: Extremely fading.

[Comparative Examples 1 to 4] The same operation as in Examples 1 to 4 was performed on comparative samples, and the results are shown in Table 1.

[0029]

[Table 1]

Examples 5 to 8 (1) Coating of surface coating agent The surface coating agent of the present invention was applied to a commercially available PPC paper (Steckigt sizing degree of about 20 seconds) using a wire bar at a polymer solid content of 0.25 g / g. and m ² is applied. Drying was performed at 100 ° C. for 2 minutes using a rotary drum dryer. (2) Printing of Test Paper and Checking of Water Resistance The applied test paper was printed with cyan, magenta, yellow, and black patterns and prints using an inkjet printer BJC-600J manufactured by Canon. The color vividness after printing was measured by a colorimeter NR-3000 manufactured by Nippon Denshoku.
For water resistance, the solid printed image was immersed in flowing water of 3 liter / min for 10 minutes, and the image density before and after the test was evaluated in five levels. The color vividness is measured by L *, a
The measurement was performed in * and b * display, and cyan was represented by -b * value, magenta was represented by a * value, yellow was represented by b * value, and black was represented by L * value. Table 2 shows the results. (Judgment of water resistance) A: No change B: Color slightly exudes. C: Discoloration is recognized. D: Large discoloration. E: Almost decolorization.

[Comparative Examples 5 to 8] In the same manner as in Examples 5 to 8, tests using comparative samples were performed. The results are shown in Table 2.

[0032]

[Table 2]

[Examples 9 to 12] Oxidized starch (Ace C, manufactured by Oji Constarch) in the same manner as in Examples 5 to 8.
And the surface coating agent of the present invention were mixed at a weight ratio of 3: 1 and applied at a solid content of 0.5 g / m ² , followed by printing and subsequent tests. The results are shown in Table 3.

[Comparative Examples 9 to 12] In the same manner as in Examples 9 to 12, tests using comparative samples were performed. The results are shown in Table 3.

[0035]

[Table 3]

[0036]

The products of the present invention have improved water resistance and light resistance compared to Comparative Examples.

Claims (5)

[Claims] 1. A paper surface coating agent comprising a polymer of a monomer containing acryloyloxyethyldimethylbenzylammonium chloride and acrylic acid. 2. The paper surface coating composition according to claim 1, wherein the content of acrylic acid in all monomers is 2 to 10 mol%. 3. A paper surface coating agent comprising a mixture of an acryloyloxyethyldimethylbenzylammonium chloride (co) polymer and an acrylic acid (co) polymer. 4. A mixture of acryloyloxyethyldimethylbenzylammonium chloride (co) polymer and acrylic acid (co) polymer in a mixing ratio of 1: 0.1 to 1: 0.02. The surface coating agent for paper according to item 1. 5. The paper surface coating agent according to claim 1, wherein the paper surface coating agent is used as an ink jet printing paper by being applied to the paper surface.