JP3247766B2 - Method for producing colored coated paper and colored coated paper obtained by the method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a colored coated paper and a colored coated paper obtained by the method.
More specifically, it has a clear hue on the paper surface, and has smoothness,
The present invention relates to a method for easily producing a colored coated paper excellent in acceptability and setting property of a printing ink, and a colored coated paper obtained by the method.

[0002]

2. Description of the Related Art In the field of offset printing, paper is mainly used as a printing medium. Among them, coated paper has a smooth and glossy printing surface and ink receptivity and setability. Because of its good printability and the ability to efficiently produce clear prints, it is often used in the production of cosmetic prints.

In recent years, in order to cope with the diversification of printed matter, not only printing ink but also printed matter using colored paper having a clear hue on the printing material itself has been increasing.

[0004] For example, in a poster or an advertisement flyer, as a means for attracting attention, a cosmetic printed matter printed with offset ink on a printing paper having a clear hue is used. Such a colored printing paper must have a clear hue on the paper surface and also have basic properties such as excellent surface gloss and printability.
Therefore, in order to obtain a target printing paper, a method of first applying a color coating agent such as ink to a coated paper obtained by applying a normal coating agent has been exclusively performed.

[0005] However, in this method, a process of applying a colored coating agent is added to the usual process of producing coated paper, which results in low production efficiency as a printing paper and high production cost. There is.

Therefore, there has been a demand for a method for producing a colored coated paper capable of simultaneously providing a clear hue and basic performances such as excellent surface gloss and printability with a single application of a coating agent.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide a color coated paper which has a clear hue on the paper surface and is excellent in printability such as surface gloss, ink acceptability and setting property. To provide a manufacturing method.

[0008]

According to the present invention, the solid content of the coating composition is 1 to 50% by weight of the colorant and the average particle size is 0.04%.
4 to 1.0 μm of calcium carbonate and other inorganic extender pigments, the weight ratio of both being 50/50 to 100
/ 0-10% by weight of inorganic extender pigment, acid value 50-
250 of at least one aqueous binder resin selected from the group consisting of acrylic resin, styrene-acrylic acid resin, styrene-maleic acid resin, and styrene-acrylic acid-maleic acid resin; ,
A coating agent containing 0 to 30% by weight of another binder resin is applied to base paper at a coating amount of 10 to 40 g / m ² (dry weight), and then a hot roll heated to 90 to 160 ° C. is used. The present invention relates to a method for producing a colored coated paper, which is characterized in that the coated paper is subjected to hot press working, and a colored coated paper obtained by the method.

[0009]

Functions and Examples Conventionally used coating agents are mainly used for imparting gloss and printability, and the effect is enhanced by incorporating a large amount of an inorganic extender such as kaolin clay. I have it. Therefore, this type of coating agent is opaque in the system itself, and it was not possible to obtain a coated paper having a clear hue by simply adding a colorant.

In the present invention, calcium carbonate having a much finer particle size than that usually used is contained in an amount of 50% by weight or more of the total amount of the inorganic extender pigment, and further, a specific group having a functional group adsorbed on the surface of the inorganic extender pigment is provided. By dispersing in a binder resin, a coating agent which has good gloss and printability, and which can impart a clear hue by addition of a colorant, has been found, and a method for producing a colored coated paper which is the object of the present invention. Is completed.

Hereinafter, the present invention will be described in more detail.

The coating agent used in the present invention comprises a colorant, an inorganic extender, and an acrylic resin, a styrene-acrylic resin, a styrene-maleic resin, and a styrene-acrylic-maleic resin. It is a coating agent containing at least one selected aqueous binder resin.

First, examples of the coloring agent used in the coating agent of the present invention include dyes, inorganic colored pigments, and organic colored pigments. Among them, pigments having excellent light resistance are more preferable.

Here, as the dye, various dyes such as azo dye, anthraquinone dye, indigo dye, phthalocyanine dye, carbonyl dye, quinone imine dye, methine dye, quinoline dye and nitro dye can be used.

The inorganic colored pigments include red iron oxide,
Antimony red, cadmium red, cadmium yellow, cobalt blue, navy blue, ultramarine, carbon black, graphite and the like can be used.

The organic colored pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments,
Any of copper phthalocyanine pigments, metal-free phthalocyanine pigments, anthraquinone-based, thioindigo-based, quinacridone-based, perylene-based, perinone-based condensed polycyclic pigments, and lake pigments of acidic or basic dyes can be used.

Next, the inorganic extender pigment used in the coating composition of the present invention has an average particle size of 0.04 to 1.0 μm.
Calcium carbonate as an essential component, and other inorganic extender pigments can be used in combination as needed. Here, when the average particle diameter of calcium carbonate is smaller than 0.04 μm,
The concealing property of the obtained coating agent is reduced, and 1.0 μm
When the size is larger, the coating agent obtained on the contrary becomes opaque, and a clear hue cannot be obtained. As the particle shape of calcium carbonate, any of a cubic shape, a rice grain shape, a spindle shape, and a spherical shape can be used, but a cubic shape is preferable because good gloss is obtained.

Further, other inorganic extender pigments which can be used together include those used in common paper coating agents such as kaolin clay, aluminum hydroxide, barium sulfate, silica, talc, titanium oxide, and satin white. Pigments can be given.

In the present invention, the average particle diameter is 0.1.
The required amount of calcium carbonate of 04 to 1.0 μm is 50% by weight or more based on the total amount of the inorganic extender, and if it is less than 50% by weight, coated paper having a clear hue cannot be obtained.

Next, the aqueous binder resin used in the coating agent of the present invention is selected from acrylic resin, styrene-acrylic resin, styrene-maleic resin and styrene-acrylic-maleic resin. At least one selected.

The above resins are defined as follows.

First, acrylic resin is obtained by copolymerizing acrylic monomer, and styrene-acrylic resin is obtained by copolymerizing acrylic monomer and styrene monomer. All are copolymer resins which can be made water-soluble by alkali neutralization.

The styrene-maleic acid resin is
It is obtained by copolymerizing a styrene monomer and a maleic monomer.Styrene-acrylic acid-maleic resin is obtained by copolymerizing a styrene monomer, an acrylic acid monomer and a maleic monomer. All are copolymer resins which can be made water-soluble by alkali neutralization.

Here, the acrylic acid monomer includes
Acrylic acid, methacrylic acid, and their alkyl esters having 1 to 18 carbon atoms, hydroxyalkyl esters having 2 to 9 carbon atoms, and alkylamides having 1 to 18 carbon atoms can be used. Examples include acrylic acid or methacrylic acid, and ester compounds of these with the following monoalcohol or diol components, or amide compounds with amine components.

Monoalcohol component methanol, ethanol, propanol, butanol,
Hexanol, octanol, decanol, dodecanol, octadecanol, etc.Diol components Ethylene glycol, propylene glycol, butylene glycol, hexanediol, octanediol, nonanediol, etc.Amine components Ethylamine, diethylamine, butylamine, hexylamine, octylamine, decylamine, dodecylamine Octadecylamine, etc. Further, as the styrene-based monomer, one or more kinds of vinyl group-containing aromatic compounds having 8 to 9 carbon atoms such as styrene, α-methylstyrene, vinyltoluene and the like can be selected and used. .

The maleic acid monomers include maleic anhydride, maleic acid, and alkyl esters of maleic acid having 1 to 18 carbon atoms, hydroxyalkyl esters having 2 to 9 carbon atoms, and 1-carbon atoms. Up to 18 alkyl amides can be used, and more specifically, an ester compound of maleic anhydride and the monoalcohol component or the diol component, or an amide compound of the amine component.

The aqueous binder resin obtained by copolymerizing the above monomer components is converted to an aqueous solution by alkali neutralization and used as an aqueous binder resin varnish.
The acid value of the aqueous binder resin is in the range of 50 to 250, preferably 80 to 200.

Here, when the acid value of the aqueous binder resin is less than 50, the solubility of the resin in water is reduced, and separation and sedimentation are caused. On the other hand, when the acid value is more than 250, the water resistance is reduced, and a preferable result is obtained. I can not get it.

Further, the glass transition temperature of the aqueous binder resin is -50 to 120 ° C, more preferably 20 to 1 ° C.
If the temperature is lower than this range, the releasability of the obtained coating agent from the hot roll at the time of press working is lowered. On the other hand, if the temperature is higher, the film strength is reduced and creases are generated.

Further, the molecular weight (weight average molecular weight, the same applies hereinafter) of the aqueous binder resin is from 3,000 to
100,000, especially 5,000-30,000
Is preferable.

As the alkali agent for neutralizing the aqueous binder resin, an inorganic alkali such as aqueous ammonia or an alkali metal hydroxide, or an organic alkali such as an organic amine can be used. Sodium hydroxide, potassium hydroxide and the like can be used as oxides, and monoethanolamine, diethanolamine, triethanolamine, morpholine and the like can be used as organic amines.

In order to produce the coating composition of the present invention using the above-mentioned colorant, inorganic extender pigment and aqueous binder resin varnish, a method of stirring and mixing the respective materials using a stirrer such as a high-speed mixer is used. In addition to the above, a method of further dispersing the stirred mixture with a disperser such as a bead mill or a ball mill can also be used.

In particular, when a coating agent obtained by a dispersion treatment with the above-mentioned dispersing machine is used, a coating agent layer having good gloss and a clear hue can be formed.

The coating composition of the present invention includes other resin binders, water-miscible solvents, and release agents, which are used in ordinary coating compositions, as long as the performance of the coating composition of the present invention is not deteriorated. Various additives such as an antifoaming agent and a pigment dispersant can be mixed.

Examples of other resin binders include aqueous resins such as polyvinyl alcohol and water-soluble celluloses, or aqueous styrene resins obtained by using maleated polybutadiene as an emulsifier, aqueous SBR emulsion, aqueous shellac emulsion, and styrene-maleic emulsion. Aqueous acid resin emulsion, aqueous styrene-acrylic resin emulsion, aqueous emulsion of styrene-maleic acid-acrylic resin and the like can be given.

As the water-miscible solvent, lower alcohols, polyhydric alcohols, and their alkyl ethers or alkyl esters can be used.

When these other resin binders are used in combination, 60% by weight or more of the total amount of the specific aqueous resin binder and the other resin binders has a glass transition temperature of 20 to 20%.
It is preferable that the temperature be in the range of 100 ° C. in order to ensure the releasability from the hot roll at the time of press working and the film strength of the obtained coating layer.

In the coating composition comprising the above components, the content of each component is, first, 1 to 50% by weight of the coloring agent and 20 to 74% by weight of the inorganic extender pigment, based on the total solid content of the coating composition. %, Aqueous binder resin 25 as an essential component in the present invention
-50% by weight, and other aqueous binder resins in the range of 0-30% by weight.

The total solid content in the coating agent varies depending on the coating method of the coating agent, but is generally in the range of 20 to 65% by weight.

Next, a method for producing the colored coated paper of the present invention will be described.

First, as the base paper on which the coating agent according to the present invention is applied, general high quality paper or neutral base paper is used, and the coating agent can be directly applied to the base paper.
Furthermore, it is also possible to apply the composition to an undercoat with another coating agent.

Coating can be carried out during or after papermaking. Examples of the coating machine include a usual roll coater, doctor blade coater, knife edge coater, curtain coater, gravure coater, bar coater and the like. Can be used. Further, it can be coated on one side or both sides of the base paper, and the coating amount is usually 10 to 40 g / m ² (dry weight) in one or more coatings.
Is preferable.

As the hot pressing, a direct or indirect casting method in which a base paper is coated with a coating agent and then the coating agent is wet while the coating agent is wet, or an acid treatment after coating is used. Either the gelling casting method of hot pressing after solidifying the working agent, or the raster processing of hot pressing after the coating agent has dried,
As a result, the sheet is glossy and becomes printing paper.

The hot pressing is usually performed at 90 to 160
Using a mirror-finished metal roll heated to 30 ° C. and at a line speed of 10 to 150 m / min.
It is performed under the condition of a linear pressure of 150 kg / cm to 150 kg / cm. When the heating temperature of the metal roll is lower than the above range, a reduction in press efficiency and poor surface smoothness are caused.On the other hand, when the heating temperature is higher than the above range, a decrease in press suitability and deterioration of the coating agent layer due to bumping of water are caused. Invite.

The printing paper manufactured by the above manufacturing method is a printing paper that can be printed by a normal offset printing method, has excellent surface gloss, good printability, and a clear hue.

Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In the following, “parts” and “%” mean “parts by weight” and “% by weight” unless otherwise specified.

Aqueous Binder Resin Varnish Production Example 1 600 parts of ethyl acetate was charged into a four-necked flask equipped with a stirrer, a condenser, and a nitrogen gas inlet tube, heated to 75 to 78 ° C., and then introduced with nitrogen gas. Methacrylic acid 100
, 250 parts of methyl methacrylate, 50 parts of 2-ethylhexyl acrylate, and 4 parts of ditertiary butyl peroxide as a reaction initiator were added dropwise over 2 hours. After random copolymerization for 2 hours while maintaining the same temperature, the solvent was evaporated under reduced pressure to obtain an aqueous binder resin having an acid value of 161 and a Tg (glass transition temperature, the same applies hereinafter) of 66 ° C.

After crushing 400 parts of the aqueous binder resin, the mixture was stirred and mixed in 600 parts of water in which an equivalent amount of ammonia was dissolved, and heated and dissolved at 80 ° C. to obtain an aqueous binder resin varnish No. 1 having a solid content of 40%. I got 1.

Production example 2 of aqueous binder resin varnish Production example of aqueous binder resin varnish except that the monomer composition was changed to 100 parts of methacrylic acid, 120 parts of methyl methacrylate, 130 parts of styrene and 50 parts of 2-ethylhexyl acrylate. Aqueous binder resin varnish No. 1 having a solid content of 40% under the same conditions as in No. 1. I got 2.

(Aqueous Binder Resin Acid Value 161, Tg 65 ° C.) Aqueous Binder Resin Varnish Production Example 3 The monomer composition was changed to 100 parts of methacrylic acid, 100 parts of methyl methacrylate, 100 parts of styrene, and 100 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish was changed to No. 1. I got 3.

(Aqueous Binder Resin Acid Value 161, Tg 31 ° C.) Aqueous Binder Resin Varnish Production Example 4 The monomer composition was changed to 50 parts of methacrylic acid, 150 parts of methyl methacrylate, 150 parts of styrene, and 50 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish was changed to No. 1. I got 4.

(Aqueous Binder Resin Acid Value 81, Tg 63 ° C.) Aqueous Binder Resin Varnish Production Example 5 The monomer composition was changed to 100 parts of methacrylic acid, 100 parts of methyl methacrylate, 100 parts of styrene, and 100 parts of 2-hydroxyethyl methacrylate. Part, and aqueous binder resin varnish No. 40% solids under the same conditions as in Production Example 1 of aqueous binder resin varnish except that the amount was changed to 80 parts of 2-ethylhexyl acrylate. I got 5.

(Aqueous Binder Resin Acid Value 161, Tg 69 ° C.) Aqueous Binder Resin Varnish Production Example 6 The monomer composition was changed to 100 parts of methacrylic acid, 100 parts of methyl methacrylate, 100 parts of styrene, and 50 parts of acrylamide.
Parts, except for changing to 50 parts of 2-ethylhexyl acrylate, under the same conditions as in Production Example 1 of aqueous binder resin varnish,
Aqueous binder resin varnish No. 40% solids I got 6.

(Aqueous Binder Resin Acid Value 161, Tg 70 ° C.) Aqueous Binder Resin Varnish Production Example 7 The monomer composition was changed to 50 parts of methacrylic acid, 40 parts of methyl methacrylate, 40 parts of styrene, and 270 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish was changed to No. 1. I got 7.

(Acid Value of Aqueous Binder Resin 81, Tg-47 ° C.) Aqueous Binder Resin Varnish Production Example 8 Aqueous binder resin varnish production was conducted except that the monomer composition was changed to 249 parts of monobutyl maleate and 151 parts of styrene. Under the same conditions as in Example 1, the aqueous binder resin varnish No. I got 8.

(Aqueous Binder Resin Acid Value 163, Tg 88 ° C.) Aqueous Binder Resin Varnish Production Example 9 The monomer composition was changed to 40 parts of acrylic acid, 160 parts of monobutyl maleate, 40 parts of methyl methacrylate, and 16 parts of styrene.
The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as in the aqueous binder resin varnish production example 1 except that the amount was changed to 0 part. I got 9.

(Acid Value of Aqueous Binder Resin 208, Tg 94 ° C.) Aqueous Binder Resin Varnish Production Example 10 The monomer composition was changed to 20 parts of methacrylic acid, 100 parts of methyl methacrylate, 180 parts of styrene, and 100 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish was changed to No. 1. No. 10 was produced, but was in a cloudy state and was not subjected to an evaluation test.

(Acid Value of Aqueous Binder Resin 33, Tg 28 ° C.) Aqueous Binder Resin Varnish Production Example 11 The monomer composition was changed to 180 parts of methacrylic acid, 50 parts of methyl methacrylate, 60 parts of styrene, and 110 parts of 2-ethylhexyl acrylate. The aqueous binder resin varnish No. having a solid content of 40% was manufactured under the same conditions as those of the aqueous binder resin varnish production example 1 except that the varnish was changed to No. 1. I got 11.

(Acid Value of Aqueous Binder Resin 294, Tg 29 ° C.) Examples 1 to 13 and Comparative Examples 1 to 6 Organic color pigment, inorganic pigment, aqueous binder resin varnish,
The aqueous SBR resin emulsion and water were stirred and mixed with a stirrer according to the composition shown in Table 1, and then subjected to a dispersion treatment using a horizontal bead mill. 1-19 were obtained. Here, as dispersion conditions, glass beads having a particle size of about 1.7 mm were filled to 80% of the capacity of the container, and the peripheral speed of the disk was 78 m / min.

In addition, Fastogen Blue TGR (manufactured by Dainippon Ink and Chemicals, Inc.) as an organic coloring pigment, and an average particle diameter of 0.08 μmm (white luster T-
DD, manufactured by Shiraishi Calcium Co., Ltd.), 0.14 μm (Shiraishi Hana T-DD, manufactured by Shiraishi Calcium Co., Ltd.), 1.15 μm
(P-50, manufactured by Toyo Fine Chemical Co., Ltd.)
UW-90 (manufactured by EMC) as kaolin clay, SB
JSR-0624 (manufactured by Nippon Synthetic Rubber Co., Ltd., solid content 48%, glass transition temperature -1) as R resin aqueous emulsion
4 ° C.).

Each coating agent was applied on a cast base paper with a 0.15 mm diameter bar, left at room temperature for 1 minute, immersed in a coagulating liquid (5% calcium formate aqueous solution),
Using a mirror drum heated to 0 ° C., a line speed of 6
Gloss finishing was performed under the conditions of 0 m / min and a linear pressure of 100 kg / cm to obtain coated papers of Examples 1 to 13 and Comparative Examples 1 to 6.

The coated papers obtained in Examples 1 to 13 and Comparative Examples 1 to 6 were evaluated for gloss, offset ink setting property, water resistance and press suitability. The results are shown in Table 2.

The evaluation was performed by the following method.

(1) Hikarizawa A 60-degree gloss value was measured with a gloss meter, and the gloss was evaluated from the value. Evaluation criteria A: Measured value of 90 or more B: Measured value of 80 or more and less than 90 C: Measured value of less than 80 (2) Setability of offset ink 0.1 cc of offset ink using RI tester / 200cm
Printing was carried out at the height of ^{2, and} a set test was performed with an offset ink set tester. The setting property of the offset ink was evaluated from the setting time.

Evaluation criteria A: Set time is less than 1 minute B: Set time is 1 minute or more and less than 3 minutes C: Set time is 3 minutes or more (3) Water resistant coated paper (4 cm × 5 cm) )), 0.1 ml of water is dropped on the coated surface, the coated surface (dry surface) of the same coated paper is put thereon, a load of 1 kg / cm ² is applied, and the coated paper is left at 25 ° C. for 24 hours. The coated paper was peeled off, and the water resistance was evaluated from the state at that time.

Evaluation Criteria A: Both coated surfaces peel off without resistance B: Pigment slightly migrates to the mating surface upon peeling C: Coated surfaces adhere to each other (4) Suitability for press At that time, the transfer of the coating layer to the mirror-surface drum was evaluated by visual judgment.

Evaluation Criteria A: No transfer to mirror-surface drum B: Partial transfer to mirror-surface drum C: Full transfer to mirror-surface drum (5) Coloring property Coloring of the surface of the coating agent layer after casting. The properties were visually checked.

Evaluation Criteria A: Clear B: Slightly dull C: Very dull (6) Foldability After folding the coated paper with its coated side inside, a cellophane tape is applied to the coated side. The cleaving property was evaluated based on the state of the coating agent layer after peeling and the amount of peeling.

Evaluation Criteria A: No cracks occurred in the coating agent layer and no peeling occurred. B: Cracks partially occurred in the coating agent layer but did not peel off at the fold portions. C: Partially occurred in the coating agent layer. Cracks are generated and the folds are peeled. D: Cracks are generated in the entire coating agent layer and the folds are peeled.

[0070]

[Table 1]

[0071]

[Table 2]

[0072]

As described above with reference to the embodiments,
By applying the coating agent specified in the present invention to base paper and subjecting it to hot press processing, it imparts excellent smoothness, print ink receptivity and setability, and has a clear hue on the paper surface. Can be manufactured.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Mitsuru Kojima 1-23-37 Edobori, Nishi-ku, Osaka-shi Inside Saka Tynex Co., Ltd. (56) References JP-A-4-228698 (JP, A) JP-A-1- 97295 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) D21H 11/00-27/42

Claims (3)

(57) [Claims] A colorant of 1 to 50 as a solid content of a coating agent.
Inorganic pigment 1 consisting of calcium carbonate and other inorganic pigments having a weight percentage of 0.04 to 1.0 μm and an average particle size of 50/50 to 100/0.
At least one selected from the group consisting of acrylic resin, styrene-acrylic resin, styrene-maleic resin, and styrene-acrylic-maleic resin having an acid value of 0 to 74% by weight and an acid value of 50 to 250; 25 to 50% by weight of a kind of aqueous binder resin, other binder resin 0
Coating agent containing up to 30% by weight of base paper
A method for producing a colored coated paper, which comprises applying a coating at 40 g / m ² (dry weight), followed by hot pressing using a hot roll heated to 90 to 160 ° C. 2. 60% by weight or more of the total binder resin,
The method according to claim 1, wherein the glass transition temperature is in the range of 20 to 100C. 3. A colored coated paper obtained by the method for producing a colored coated paper according to claim 1.