JPH08400Y2 - Pearl pigment coated paper - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pearl pigment coated paper, and more specifically, even if a pearl pigment coated layer is provided on both sides of a base sheet, it does not cause blocking and has good printability. It's about paper.

[0002]

2. Description of the Related Art Since pearlescent pigment coated paper has a unique and beautiful appearance of pearly luster, it is used for publication of book covers, book counters, etc., for advertising of pamphlets, posters, etc., boxing, labeling and packaging. It has been used for stationery such as stationery. There have been many proposals in the past regarding this pearl pigment coated paper. For example, Japanese Patent Publication No. 39-29267 discloses that a basic lead carbonate pearl pigment is coated with an adhesive composed of casein and melamine-formaldehyde resin or urea formaldehyde resin, synthetic resin latex,
In Japanese Patent Publication No. 51-45682, a base paper having a large number of textured uneven distributions which are patterned and distributed is coated with a pearl luster pigment. In Japanese Patent Publication No. 1-47597, an aqueous pigment coating layer is formed on a base paper. It has been proposed that an aqueous pearl pigment coating layer and a surface-treated layer containing a water-soluble polymer as a main component are sequentially provided on the above.

On the other hand, the performance required for pearl pigment-coated paper has become more and more sophisticated these days, but in all cases, what is commonly required is a design that includes a pearly feeling. It may be excellent in effect and printability, particularly offset printability. In addition, the range of use thereof is wide, and there is a demand for a structure in which a pearl pigment coating layer is provided on both surfaces of a base sheet.

[0004]

[Problems to be Solved by the Invention] To obtain a pearl pigment coated paper having pearl pigment coated layers on both sides, simply consider
The pearl pigment coating liquid used conventionally should be coated on both sides of the base sheet, but as a result of investigation, it was found that this method causes a blocking problem. It was also found that this tendency is particularly great when stacking sheets of paper after offset printing. Blocking is a phenomenon in which when two or more sheets of paper are superposed, the surfaces of the sheets that are in contact with each other adhere to each other due to temperature, humidity, pressure, and the coating composition.If this happens, printing cannot be performed, the sheets of paper are destroyed, etc. Will be a fatal problem. The reason why blocking occurs when the pearlescent pigment coating layers are formed on both sides of the base sheet is not clear.However, the influence of the adhesive component contained in the adjacent pearlescent pigment coating surface probably affects the pearlescent pigment coating surface on one side of the base sheet. It was estimated that this was because it was larger than when the work layer was formed (the coated surface and the back surface of the base sheet were in contact). In addition, it is estimated that the tendency of blocking after offset printing is particularly large, because the dampening water used during printing is absorbed on the paper surface, which causes the humidity in the vicinity of the paper surface to increase, further promoting blocking. The present invention has been made to solve the above problems.

[0005]

Means for Solving the Problems As a result of intensive studies by the present inventors, the above problems have been solved by using two kinds of specific water-dispersible resins and a water-soluble polymer compound as an adhesive. There is the greatest feature of the present invention. That is, the gist of the present invention will be described with reference to the drawings. 100 parts by weight of pearl pigment (dry part by weight, the same applies hereinafter) is added to a water-dispersible resin 1 having a glass transition point of 40 ° C. to 80 ° C. To 3 parts by weight, 0.5 to 3 parts by weight of a water-dispersible resin having a glass transition point of 20 ° C. or less, and a water-soluble polymer compound are mixed at a ratio of 10 to 50% to the water-dispersible resin. The purpose is to obtain a pearl pigment-coated paper in which the pearl pigment-coated layer 2 is formed on both sides of the base sheet 1 with a coating material in which 100 to 500 parts by weight of the adhesive obtained is mixed.

The pearl pigments that can be used in the present invention are natural pearl essence, mica powder, basic carbonate, titanium oxide-coated mica powder and the like. Particle size and titanium oxide coverage must be selected in order to obtain adhesion strength to base paper, ink receptivity, and desired pearly luster, but use titanium oxide-coated mica powder because the range of choice is widest. Is preferred. The effective particle size is 5 to 150 μm, more preferably 10 to 100 μm. Titanium oxide-coated mica powder is disclosed, for example, in JP-B-53-47375 and JP-B-5.
It is produced by the method described in JP-A No. 4-34010 and JP-A No. 58-149959.

The water-dispersible resin used in the present invention means acrylic acid or its ester, methacrylic acid or its ester, vinyl chloride, vinylidene chloride, vinyl acetate, acrylonitrile, butadiene, styrene, etc. which are emulsion-polymerized or emulsion-copolymerized. It is a water-dispersible emulsion (latex) and also includes a polymer into which a functional group such as a carboxyl group or a hydroxyl group is introduced.

The coating layer of the water-dispersible resin generally has a high tackiness when the glass transition point of the resin is low and a low tackiness when the glass transition point is high. Therefore, in order to prevent blocking, it is sufficient to use a water-dispersible resin having a high glass transition point, but the use of this resin alone lowers the adhesive strength. On the other hand, when a water-dispersible resin having a low glass transition point is used alone, the adhesive force is obtained but the blocking problem occurs. As a result of further investigations by the present inventors, 1 to 3 parts by weight of a water-dispersible resin having a glass transition point of 40 ° C. or higher and 80 ° C. or lower is used, and a water-dispersible resin having a glass transition point of 30 ° C. or lower is used. It was found that by mixing 5 to 3 parts by weight, adhesive strength is practically sufficient and pearl pigment-coated paper (double-sided coating) that does not cause blocking can be obtained.

However, if only water-dispersible resin is used for the adhesive, the water absorbency of the paper surface is insufficient, and it has been found that the printing performance, particularly the offset printing suitability, which is an important performance as a pearl pigment coated paper, is insufficient as it is. It was As is well known in offset printing, dampening water is used at the time of printing, but it is preferable that the paper surface of the printing paper absorbs this water moderately.If the water absorption of the paper surface is insufficient, the ink easily emulsifies and scumming occurs. Cause a trouble called. The present inventors have solved this problem by mixing the water-soluble polymer compound with the water-dispersible resin at a ratio of 10 to 50%.

The present inventors first dissolved various water-soluble polymers in water and determined the concentration when the viscosity was adjusted to 100 CPS. Further, a pearl pigment-coated paper in which only the kind of the water-soluble polymer was changed was prepared by the same formulation as in Example 2 described later, and the water absorption (cobb size degree) of the paper surface was determined. The results are shown in Table 1.
Shown in

[0011]

[Table 1] Evaluation results of various water-soluble polymers

Examples of the water-soluble polymer compound include starch or its derivatives, carboxymethyl cellulose (CMC),
Known substances such as fibrin derivatives such as hydroxyethyl cellulose (HEC), casein, polyvinyl alcohol (PVA) and the like can be used. However, casein has a large effect of emulsifying the ink during offset printing, and causes troubles of scumming in some cases, and starch, a fibrin derivative, and polyvinyl alcohol have a practical dissolved concentration as shown in Table 1. Since it is low, it is difficult to set the paint concentration to the optimum concentration, and since many of them have poor water absorbency, the present invention has a relatively high dissolution concentration as a water-soluble polymer.
It is preferable to use a starch derivative which is also excellent in water absorption. As the starch derivative, known ones such as oxidized starch, dialdehyde starch, cationized starch, acetylated starch, phosphoric acid esterified starch, hydroxyethylated starch and the like can be used. The water-soluble polymer compound is added to the water-dispersible resin in an amount of 10 to 50%, preferably 20 to 30%. If it is less than this ratio, water absorption is insufficient, and if it is too large, the surface strength is insufficient.

In the present invention, 100 parts by weight of the pearl pigment is added to 100 to 500 parts by weight of the adhesive mixed in the above range to form a paint on both sides of the base sheet. If the amount of the adhesive is less than 100 parts by weight, the strength of the coating layer will be insufficient, and if it exceeds 500 parts by weight, the pearlescent feeling will be insufficient. The pearlescent pigment coating is prepared by adding a pearlescent pigment, for example, titanium oxide-coated mica powder to a tank in which the adhesive is gently mixed and stirred. Since vigorous stirring may destroy the mica powder, it is preferable to rotate gently.

At this time, it is possible to add auxiliary materials such as dyes, colorants such as pigments, waterproofing agents, viscosity modifiers, etc. to the coating material depending on the purpose. The pearl pigment paint prepared as described above,
It is coated on the coated base paper with an air knife coater, roll coater, blade coater, etc., but in order to obtain a uniform distribution state of the pearl pigment in the coating layer, it is preferable to coat with an air knife coater. . The coating layer may be formed by a paint having the same formulation on the front and back sides, or may be formed by different formulations. In particular, if pearl pigments having different particle diameters or hues are used, or a coloring agent is added to form different hues, the design effect can be further enhanced.

The coating amount is usually ^{2 to 20} g / m ^{2 on} one side.
However, in order to obtain an effective pearly luster, 5-8 g /
m ² is preferred. In the present invention, any coated base paper can be used. For example, in order to obtain a pearlescent luster, a base paper which has been previously coated with a pigment to smoothen the surface, or Japanese Patent Laid-Open No.
A base paper coated with a coloring pigment such as No. 0-16991 may be used. Further, by using a base paper having a large number of uneven projections that are patterned and distributed as in JP-B-51-45682, a pearl pigment coated paper having a design effect with a clear pattern on the surface is used. Can be obtained.

Further, when Japanese paper, high-quality paper, paperboard, flame-retardant paper, synthetic paper, paper made of non-woven fabric, film, synthetic fiber paper, synthetic pulp paper, etc. is used as a base, pearl pigment coating with a unique texture is obtained. You can obtain craft paper. Further, in order to obtain a pearl luster having a soft feeling, which is not present in these conventional pearl pigment-coated papers, it is only necessary to use a base paper which is finely embossed. Although it is difficult to express with fine embossing,
The pitch and unevenness are very small, and it is difficult to visually observe the unevenness of the embossing, but the embossing is such that the soft feeling can be clearly confirmed by touch. When the pearl coated paper of the present invention is made using this base paper, the surface gloss increases, so it becomes possible to subtly see the fine embossed irregularities that could not be seen until now, and there is a soft feeling that has never been seen before. A pearl pigment coated paper can be obtained. At this time, if the base paper is colored with a dye or the like, the design effect can be further enhanced.

[0017]

[Example 1] Grain weight of 180 g / m ² on fine paper
m, 100 parts of mica powder having a titanium oxide coverage of 28% (dry weight part, the same applies hereinafter), 60 parts of an acrylic emulsion having a glass transition point of 40 ° C., 30 parts of a glass transition point of 20 ° C. acrylic emulsion, and 10 parts of phosphorylated starch. A coating material was prepared by adding it as an adhesive, and 5 g / m ² was coated on each side using an air knife coater to obtain a pearl pigment coated paper.

The physical properties of the pearl pigment-coated paper were evaluated by changing the glass transition point of the acrylic emulsion and the addition amount of each material as shown in Table 2 with the same material. Table 2 shows the formulations and evaluation results of each Example and Comparative Example. The evaluation is a 5-point evaluation, 5 is excellent, 4 is good, 3 is acceptable, 2 is inferior, and 1 is
Indicates no. Also, the pearly luster is visually judged,
Blocking resistance is judged by the degree of blocking after contacting the paper surfaces at 40 ° C. and 90% RH and applying a pressure of 500 g / cm ² for 24 hours, and water absorption is judged by the hump size degree (2 minutes). Then, the surface strength was judged by performing solid printing with the ink of Tack 30 using an IGT tester and observing the peeled state of the paper surface.

[0019]

[Table 2] Examples and comparative examples Prescription and evaluation results

[0020]

As described above, the pearl pigment coated paper of the present invention is constructed and has the following remarkable effects. Blocking does not occur even when papers are stacked, and printability is good. Since the pearl pigment coating layer is formed on both sides of the base sheet, it can exert an unprecedented design effect, and is suitable for applications such as posters, calendars, cut-off book covers, facings, menus, catalogs, greeting cards, etc. Available.

[Brief description of drawings]

FIG. 1 is a partially enlarged sectional view of a pearl pigment coated paper of the present invention.

[Explanation of symbols]

 1 Base sheet 2 Pearl coating layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D21H 27/00 D21H 1/28 Z 5/00 Z

Claims (2)

[Scope of utility model registration request] 1. To 100 parts by weight of a pearl pigment, 1 to 3 parts by weight of a water-dispersible resin having a glass transition point of 40 ° C. to 80 ° C., and 0.
100 parts of an adhesive obtained by mixing 5 to 3 parts by weight and a water-soluble polymer compound in a ratio of 10 to 50% with respect to a water-dispersible resin.
A pearl pigment-coated paper, characterized in that a paint mixed in an amount of up to 500 parts by weight is formed on both sides of a base sheet. 2. The pearl pigment coated paper according to claim 1, wherein the water-soluble polymer compound is a starch derivative.