JPH04228698A - Coated sheet for color printing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated sheet, and more particularly to a coated sheet for colored printing without uneven coloring.

0002

[Prior Art] Among coated papers for printing, such as art paper, coated paper, cast coated paper, and lightly coated paper, colored coated papers for printing are particularly high-quality and differentiated. It is highly rated for these reasons and is used in a wide range of fields. Such colored coated paper for printing is ■. A base paper that has been colored in advance to a desired shade, and then an uncolored coating layer is provided on this. ■． Base paper is colored in advance to a desired shade, and a coating layer colored in the desired shade is provided on this. ■． A coating layer colored in the desired shade is provided on uncolored base paper. etc. However, in the case of coated paper for printing,
Since the coating liquid constituting the coating layer is uncolored, there is a problem in that the color of the base paper is hidden by the formation of the coating layer, making it difficult to express the original color of the base paper. In the case of coated paper for printing (■ and This is a method of providing a colored coating layer by coating.

[0003] However, since base paper has minute irregularities in formation, minute disturbances in smoothness, capillaries between pulp fibers, etc., when the above-mentioned colored coating liquid is applied to base paper, the amount of water in the coating liquid is Colored dyes dissolved or dispersed in water move in the Z direction together with the water because of the phenomenon of irregular movement of water, that is, the difference in water penetration in the non-uniform parts of the base paper and the difference in water migration during drying. As a result, the dye distribution in the coated layer becomes random, resulting in uneven color shading.

[0004] This problem appears particularly when a blade coater is used to apply a colored coating liquid to a base paper. The reason for this is that when applying a coating liquid with a blade coater, differences in the amount of coating inevitably occur due to unevenness on the surface of the base paper. In other words, areas with a large amount of coating have a large amount of colored dye dissolved or dispersed in water, and the amount of dye that moves freely (moves) during penetration and drying as described above is also large, and areas with a small amount of coating have a large amount of colored dye dissolved or dispersed in water. The color density is higher than that of the original, and uneven color shading is more likely to occur.

[0005] Such a phenomenon occurs not only when the support is the above-mentioned base paper, but also when a synthetic resin film is used, for example, when the coated layer surface becomes uneven or drying becomes uneven. The current situation is that this problem occurs in many cases, and improvements are desired. In order to avoid these drawbacks of the prior art, it is possible to change the coating composition to one that easily retains water, such as changing the type and amount of pigment in the coating composition, adding a water-retaining agent, etc. However, changing the type and amount of pigment can cause changes in the viscosity and fluidity of the coating liquid, blade streaks, breathing, wear of the blade blade during the coating process, increased wind pressure of the air knife coater, and occurrence of roll coating patterns. This is undesirable because it causes deterioration such as the formation of rod streaks and changes in dryness, thereby deteriorating the suitability for application. There is also a method of adding a water retaining agent such as carboxymethyl cellulose or sodium alginate, but this increases the viscosity of the coating solution, leading to deterioration of coating suitability as described above, and furthermore, the smoothness of the surface of the coated sheet, printing suitability, etc. This is undesirable because it affects changes in the original functions and quality of the paper.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a coated sheet for printing that is colored evenly.

[0007]

[Means for Solving the Problems] The present invention provides a coated sheet for printing having a coating layer mainly composed of pigment and adhesive, in which the coating layer contains a pigment coated with a colored dye. This is a colored coated sheet for printing, which is characterized by the following.

[0008]

[Means] In the above structure, the type of pigment as the base particles to which the colored dye is attached may be any of the known inorganic pigments and organic pigments that can be used for constructing the coating sheet for printing.

[0009] Examples of inorganic pigments include heavy calcium carbonate,
Examples include light calcium carbonate, clay, kaolin, aluminum hydroxide, titanium oxide, barium sulfate, zinc oxide, satin white, and talc. As organic pigments,
Examples include polystyrene, melamine-formaldehyde resin, urea-formaldehyde resin, and the like.

[0010] The particle diameter of these pigments as base particles is as follows:
If the colored dye to be attached to the surface is a colored pigment,
Even if the colored pigment is a soluble dye, the average particle diameter is 0.3 to 15 μm (for particle size measurement, particle size distribution measurement is required). The object is a container (using "SA-CP3" manufactured by Shimadzu Corporation).

[0011] When the average particle diameter of the base particles is less than 0.3 μm, the surface area occupied by the pigment increases. Therefore, if the amount of colored dye is kept constant, the amount of colored dye that adheres to the surface of each base particle will naturally decrease. Therefore, in order to correspond to this and attach a predetermined amount of colored dye,
The amount of colored dye has to be increased and as a result,
There is a problem that the functions of the base particles, such as printing suitability, are impaired.

[0012] When the average particle diameter of the base particles is 15 μm or more, the adhesion distribution of colored dyes on the surface of each base particle becomes uneven, and the water retention property further decreases, making it difficult to sufficiently improve the coloring unevenness. cannot be obtained. In the above configuration, the colored dye that adheres to and coats the surface of the pigment as the base particle is an organic dye or a colored pigment that is dissolved or dispersed in water.

Examples of organic dyes include natural dyes represented by indigo, azo dyes, anthraquinone dyes, indigoid dyes, sulfur dyes, triphenylmethane dyes, xanthene dyes, alizarin dyes, acridine dyes, quinone imine dyes, thiazole dyes, and methine dyes. , nitro dyes, nitroso dyes, cyanine dyes, and other organic dyes that can be dyed by an appropriate dyeing method.

The colored pigments include organic powders insoluble in water, oil, etc., such as natural colored pigments represented by madder lake, logwood lake, cochineal lake, etc., the above-mentioned organic dyes insoluble in water, or organic dyes insoluble in water. Organic pigment dyes made by making the soluble organic dyes insoluble (laked) with a precipitant, etc., and inorganic pigments such as carbon black, graphite, yellow lead, zinc yellow, ocher, iron oxide, red iron oxide, ultramarine blue, navy blue, and zinc green. Examples include colored pigments, but they can be used in any form of liquid, dispersion, or powder. However, in the case of dispersions and powders, the average particle diameter should be 1 due to the adhesion to the base particles and coloring properties.
It is most preferably 0.01 to 0.3 μm, preferably 0.01 to 0.3 μm. Among these various colored dyes, those in which organic pigment dyes are attached to inorganic pigments have excellent fading resistance (less phenomenon in which the degree of coloring decreases due to light, heat, and humidity).
It is preferable in that it exhibits the following.

[0015] As a method for attaching a colored dye to the surface of a pigment serving as a base particle, various methods conventionally known as methods for modifying the surface of powder can be used. For example, particles can be modified by (1) coating modification method, (2) topochemical modification method, (3) mechanochemical modification method, (4)
There are modification methods using encapsulation, (5) modification methods using high energy, and (6) modification methods using precipitation. In the case of the present invention, the modification method is not limited to these modification methods, but any modification method that can attach a colored dye to the surface of pigment particles that are base particles,
You can use any method.

[0016] Here, the mechanochemical modification method (3) will be explained. Originally, the mechanochemical modification method was developed and used as a method for adhering solids to each other by utilizing the electrification phenomenon of powders, but according to the study by the present inventors, it was found that pigments as base particles It was also confirmed that excellent effects were obtained in terms of adhesion of colored dyes to. Examples of devices currently on the market for concretely carrying out mechanochemical modification methods include devices such as Mechano Mill, Ong Mill, and Hybridization System. According to the modification method using these devices, the original function of the pigment as a base material is not impaired, and it can be preferably used because of the advantages that the adhesion of the dye is very high.

The most preferred among these modification methods is the hybridization system method. To explain this method in detail, after forming an ordered mixture in which child particles (powder) are arranged around a pigment, which is a base particle, by utilizing the charging phenomenon of powder, it is then introduced into a hybridizer. In this method, mechanical and thermal energy is repeatedly applied to each particle efficiently, and immobilization is carried out in 1 to 10 minutes.

[0018] Even when this method is used in the production of the coated sheet for printing according to the present invention, the child particles (liquid or dispersion) are uniformly and effectively adhered to the outer surface of the parent particles, resulting in excellent results. A good adhesion effect can be obtained. Therefore, in the present invention, the pigment coated with the modified colored dye as described above is contained in the coating layer, and the effective proportion of this pigment in the total pigment is the average of the base pigment. Although it varies depending on the particle size, for example, the average particle size of the base pigment is 4 to 15 μm.
In the case of m, the content is 30% by weight or more, and in the case of 0.3 to 3 μm, the content is 20% by weight or more. Incidentally, if the ratio is less than the above, the ratio of non-colored pigment in the coating layer increases, and as a result, uneven coloring is likely to occur, making it difficult to obtain a coated sheet for colored printing with excellent coloring unevenness. becomes difficult.

[0019] In constituting the present invention, the colored coating liquid includes:
Use of general inorganic or organic pigments without coloring, binders such as starch, casein, polyvinyl alcohol, and latex, dispersants, antifoaming agents, water retention agents, waterproofing agents, preservatives, and other auxiliaries. There are no restrictions on this in any way. Furthermore, there are no restrictions on the preparation method, type of support, coating method, drying method, finishing method, etc. of the colored coating solution.

The structure of the present invention is characterized in that the coating layer contains a pigment coated with a colored dye as described above. Significant effects can be obtained when applied to paper. Matte coated paper for printing has a strong image of luxury because it expresses an elegant and deep tone compared to general coated paper for printing, which has a high gloss.For example, it is used for various books and magazines. cover,
It is widely used for everything from high-end posters, catalogs, etc. to text paper, and is one of the coated papers for printing with high general-purpose value.However, for reasons such as visual sense, luxury, and distinction, colored matte coated paper for printing is used. The value of existence is also highly evaluated.

[0021] The coating liquid for forming the coated paper for matte printing contains inorganic pigments, mainly heavy calcium carbonate, which have a coarser particle size than the coating liquid for forming the general coated sheet for printing. used. Therefore, water retention is poor, and the aforementioned water penetration and migration during drying occur significantly. In order to avoid this, the current methods have been to use pigments with small particle diameters even at the expense of white paper gloss, or to add water retention agents at the expense of coating suitability.

Therefore, by adopting the present invention in the structure of the coated paper for matte printing, the coating suitability is not impaired during the manufacturing stage of the coated paper, and the coated paper for matte printing obtained has the following properties:
Without sacrificing the properties of coated paper for general printing,
It has low white paper gloss, looks elegant, does not generate printing mottles, and can be made into a colored matte coated paper for printing with excellent printability.

[0023]

[Examples] The effects of the present invention will be explained below with reference to Examples, but the present invention is not limited thereto. "Parts" and "%" in Examples refer to "parts by weight" and "% by weight," respectively.
'', and for liquids, the solid amount is shown.

[0024]

[Example 1] Hybridizer (Mo
Del No., NHS-1), a blue colored pigment (trade name "TB-2680") was added to 70 parts of heavy calcium carbonate with an average particle diameter of 11 μm as a base particle.
．． A 3 part deposited dye-coated pigment was prepared. 70.3 parts of this dye-coated pigment, 30 parts of heavy calcium carbonate with an average particle size of 3.5 μm, 0.2 parts of sodium polyacrylate as a dispersant, 9 parts of styrene-butadiene copolymer latex, and oxidized starch. A 63% solids coating solution consisting of 7 parts was prepared.

This coating liquid was coated on both sides of base paper of 74 g/m2 with a blade coater so that the dry weight was 25 g/m2 per side. After drying, the density of the coated paper was 1.10.
A colored matte coated paper for printing was obtained by performing super calendering so that the weight of the paper was 100 g/cm3. The coloring unevenness of the obtained matte printing coated paper is shown in Table 1. Furthermore, there was no decrease in coating suitability or general quality characteristics required as coated paper for matte printing.

[0026]

[Example 2] Hybridizer (Mo
Del No., NHS-1) was added to 80 parts of kaolin (Kaolin/UW-90 manufactured by ECM Co., Ltd.) with an average particle diameter of 0.6 μm as a base particle, and an average particle diameter of 0.1 μm.
A dye-coated pigment was prepared to which 0.5 part of ultramarine blue adjusted to m was attached. 80.5 parts of this dye-coated pigment, 15 parts of heavy calcium carbonate with an average particle size of 0.9 μm, 5 parts of Sachin White, and 0 parts of sodium polyacrylate as a dispersant.
．． 2 parts together using a Coles disperser to a concentration of 65%.
A pigment slurry was prepared. To this pigment slurry were added 0.2 parts of ammonia water, 10 parts of styrene-butadiene copolymer latex as an adhesive, and 3 parts of oxidized starch to prepare a coating liquid with a solid content concentration of 62%.

This coating liquid was coated on both sides of a 100 g/m2 base paper using a blade coater so that the dry weight was 25 g/m2 per side. After drying, the density of the coated paper was 1.2.
A colored coated paper for printing was obtained by supercalendering to give a density of 3 g/cm3. The uneven coloring of the obtained coated paper for printing is shown in Table 1. There was no decrease in coating suitability or general quality characteristics required for coated paper for printing.

[0028]

[Example 3] Hybridizer (Mo
Del No., NHS-1) was added to 60 parts of light calcium carbonate with an average particle diameter of 0.5 μm as a base particle, and a yellow colored pigment (trade name "TB-710 Yellow 2RN” to 0
．． A 14 part deposited dye-coated pigment was prepared.

60.54 parts of this dye-coated pigment, 40 parts of kaolin with an average particle diameter of 0.6 μm (Kaolin/UW-90 manufactured by ECM), and 0.5 part of sodium polyacrylate as a dispersant were mixed in a Coles dispersion machine. using a concentration of 60
% pigment slurry was adjusted. To this pigment slurry were added 0.5 parts of tributyl phosphate as an antifoaming agent, 1.0 parts of ammonium stearate as a mold release agent, 10 parts of a 15% casein aqueous solution dissolved in ammonia as an adhesive, and acrylic/butadiene. 16 parts of a copolymer latex of /methyl methacrylate (ratio 2:33:65) were added, and further 3 parts of ZnSO4 and water were added to prepare a coating liquid with a solid content concentration of 45%.

[0030] This coating liquid was applied to 6 casts according to the rewet casting method disclosed in Japanese Patent Application Laid-Open No. 59-216996.
A cast finish of 25 g/m 2 on one side was performed on a base paper of 4 g/m 2 to obtain a colored cast-coated paper. Table 1 shows the uneven coloring of cast coated paper. There was no decrease in coating suitability or general quality characteristics required for cast coated paper.

[0031]

[Example 4] Hybridizer (Mo
Del No., NHS-1) was added to 35 parts of heavy calcium carbonate with an average particle diameter of 11 μm as a base particle.
35.30 parts of a dye-coated pigment with 0.30 parts of a blue colored pigment (trade name "TB-2680") adjusted to an average particle size of 0.1 μm, and an average particle size of 3.5 μm.
A colored matte coated paper for printing having a density of 1.10 g/m<3> was obtained in the same manner as in Example 1 except that 65 parts of heavy calcium carbonate of 1.0 g/m<3> was used. The coloring unevenness of the obtained matte printing coated paper is shown in Table 1. Furthermore, there was no decrease in coating suitability or general quality characteristics required as coated paper for matte printing.

[0032]

[Example 5] 70 parts of heavy calcium carbonate with an average particle diameter of 11 μm as a base particle was added to 100 parts of a 1% solution of a disazo direct dye (manufactured by Nippon Kayaku Co., Ltd., trade name "KDF-Orange G"). The coated paper had a density of 1.1 in the same manner as in Example 1, except that a dye-coated pigment was used in which the direct dye was adhered to the surface of heavy calcium carbonate by dispersing and soaking for 24 hours.
A colored matte printing coated paper of 0 g/m3 was obtained. Table 1 shows the coloring unevenness of the obtained matte printing coated paper.
It was shown to. Furthermore, there was no decrease in coating suitability or general quality characteristics required as coated paper for matte printing.

[0033]

[Comparative Example 1] The dye-coated pigment used in Example 1 was not used, but instead 70 parts of heavy calcium carbonate with an average particle size of 11 μm and a blue organic pigment (trade name "TB-26") were used.
A colored matte coated paper for printing was produced in the same manner as in Example 1, except that 0.3 part of the coating liquid was added at the time of preparation of the coating liquid. Regarding the coloring unevenness of the obtained matte printing coated paper, see the table below.
Shown in 1.

[0034]

[Comparative Example 2] The dye-coated pigment used in Example 2 was not used, but instead Kaolin 8 with an average particle size of 0.6 μm was used.
0 parts, ultramarine blue adjusted to an average particle size of 0.1 μm.
Example 2, except that 5 parts were added at the time of preparation of the coating liquid.
Colored coated printing paper was produced in the same manner as above. The uneven coloring of the obtained coated paper for printing is shown in Table 1.

[0035]

[Comparative Example 3] The dye-coated pigment used in Example 3 was not used, but instead 60 parts of light calcium carbonate with an average particle size of 0.5 μm and a yellow colored pigment (trade name "TB-71") were used.
A colored cast-coated paper was produced in the same manner as in Example 3, except that 0.14 parts of 0 Yellow 2RN) was added at the time of preparation of the coating liquid. The uneven coloring of the cast coated paper obtained is shown in Table 1.

[0036]

[Comparative Example 4] Matte coating colored in the same manner as in Example 1, except that coarse calcium carbonate with an average particle size of 20 μm was used instead of heavy calcium carbonate with an average particle size of 11 μm in Example 1. Got paper. The coloring unevenness of the obtained matte printing coated paper is shown in Table 1. In addition, since the calcium carbonate as the base particles was too coarse, the blade was severely worn when coating with a blade coater.

[0037]

[Comparative Example 5] To 25 parts of heavy calcium carbonate having an average particle diameter of 11 μm in Example 1, a blue colored pigment (trade name
A colored matte coated paper was obtained in the same manner as in Example 1, except that a dye-coated pigment having 0.30 parts of B-2680") was used. The coloring unevenness of the obtained matte coated paper is shown in Table 1.

[0038]

[Table 1]

[0039]

[0040]

[Effects] The colored coated paper for printing of the present invention has a coating layer containing a pigment coated with a colored dye, so that the colored dye is directly added to the coating liquid without adhering to the pigment. This provides an excellent coated paper for colored printing with no uneven coloring compared to the conventional coated paper for colored printing composed of the following.

Claims (4)

[Claims] [Claim 1] A coated sheet for printing provided with a coating layer containing a pigment and an adhesive as main components, characterized in that the coating layer contains a pigment coated with a colored dye. Coating sheet. 2. The coated sheet for printing according to claim 1, wherein the colored dye is a colored pigment. 3. The coated sheet for printing according to claim 1, wherein the base pigment coated with the colored dye has an average particle diameter of 0.3 to 15 μm. 4. The coated sheet for printing according to claim 1, wherein the surface of the coating layer is matte.