JPH03113094A - Coated paper for printing and production thereof - Google Patents

Abstract

PURPOSE:To obtain the subject coated paper giving printed surface having excellent color concentration of printing by applying embossing to original paper, applying paint with air knife coater and forming paint coated face having smooth curved surface from projected part to inner face of depressed part. CONSTITUTION:Embossing having >=15mum average depth of depressed part is applied to original paper and paint is applied along unevenness of the emboss, then paint coated face having smooth curved surface from projected part to inner face of depressed part is formed to afford the aimed coated paper on which depth of depressed part in the original paper is almost kept.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a coated paper for printing, and more specifically,
The present invention relates to a printing coat having a paint coating surface having clear unevenness with a smooth curved surface from the convex portion to the inner surface of the concave portion.

(Prior Art) Printing coated paper having a sharply uneven surface has been conventionally used as book paper, cover material, file cover material, poster material, and the like. Coated paper for printing, which has an uneven surface, is usually manufactured by coating a base paper with paint and then embossing the paper, and then printing is performed on this paper and used as a cover material.

Coated paper for printing manufactured through the above process does not have sufficient printing density when printed on it, especially in the case of offset printing, and in particular, when using dark color ink such as black, it is difficult to maintain the original density of the ink. Prints with color density cannot be obtained.

The reason for this is that when the paint-applied surface is embossed, the greater the depth of the embossment, the more likely corners are formed at the inner bottom of the recess, and when printing on this uneven surface,
It is assumed that the printing ink does not adhere to the corners of the inner bottom of the recess, and the printing ink cannot be evenly adhered to the inner surface of the recess, resulting in insufficient color density for the entire printed surface. .

In particular, in offset printing, the pressing force of the blanket is not sufficient to remove air from the inner bottom corners of the recesses, so the air and printing ink are not completely replaced in these parts, and therefore, as described above, It is assumed that spots where printing ink does not adhere easily occur, and as a result, the color density of the printed surface is particularly insufficient on uneven surfaces printed by offset printing.

The above-mentioned phenomenon of poor replacement between the air inside the recesses and the printing ink is noticeable on an embossed surface where the embossed recesses are discontinuous and each recess is independent.
On such an embossed surface, the color density of printing is particularly insufficient.

As a method of producing a printed surface with high color density even though it is an uneven surface, printing is performed on a coated plane and then the printed surface is embossed. However, with this method, embossing by roll embossing is not possible, and flat plate embossing must be relied upon. However, flat plate embossing has extremely poor productivity and is problematic in terms of cost.

By the way, coated paper for printing has a sharply uneven surface, and when printed on this uneven surface, the effect of the sharp unevenness produces printed matter with a unique printing appearance and feel. There is a great demand for coated paper for printing having an uneven surface, and therefore there is a strong desire to improve color density when printing on an uneven surface.

(Issues to be Solved by the Invention!) The present invention is a coated paper coated with paint and has sharp unevenness, and when printed on this uneven surface, the color density of the print is very excellent. The object of the present invention is to provide coated paper for printing that allows the printed surface to appear.

(Means for Solving Problem 1x) The present invention applies a paint to the embossed surface of base paper almost along the unevenness of the embossing, and when applying the paint, the depth of the embossed concave portions of the base paper is By forming the paint application surface with a smooth curved surface from the convex part of the emboss to the inner surface of the concave part, while maintaining almost the same
This is a solution to a problem.

In the present invention, in order to develop clear unevenness, it is preferable to maintain approximately 85% or more of the depth of the embossed recesses on the base paper after coating the paint.

In the present invention, in order to clearly express the uneven surface after coating the paint, the depth of the concave portion of the embossing on the base paper is set to 15 μm.
If the depth of this recess is less than 15 μm, if a paint coating layer with a smooth curved surface is formed on this embossed surface, It becomes difficult to maintain clear unevenness.

Note that an air knife coater is the best way to uniformly apply a smooth coating layer to the entire uneven surface while maintaining the depth of the recesses on the embossed surface of the base paper.

(Function) In the coated paper for printing of the present invention, when applying paint to the uneven surface of the embossing base paper, the paint is applied almost along the unevenness, and the depth of the recesses after application is the same as the depth of the recesses of the embossing base paper. The coating layer has a smooth curved surface while maintaining almost the same thickness. Therefore, when printing on this uneven surface, the air in the recesses is replaced with the printing ink very completely, so that the ink can be uniformly adhered to the entire surface of the recesses. In other words, unlike when printing on a sheet material with a conventional uneven surface, there are no points where ink and air are not replaced in the recesses, that is, there are no ink non-adhesion points, so the color of the printed surface is There is no possibility that the concentration will be insufficient.

(Example) The present invention will be described in more detail with reference to Examples below.

Example: On one side of a base paper with a thickness of 250μ and a basis weight of 200g/rr+,
A cloth pattern pattern (average depth of the recesses is about 60 μm) is embossed, and on this embossed surface, paint A with the following composition is applied to the embossed surface at an adhesion rate of 115 g/a almost along the unevenness using an air knife coater. A paint coating layer was formed and applied to form a smooth curved surface from the to the inner surface of the recess. The depth of the recesses in the R4 coating layer was about 56 μm, and the depth of the recesses on the embossed surface of the base paper was almost maintained.

When the uneven surface obtained in the above manner was subjected to offset printing on the uneven surface of existing coated printing paper, printing with extremely excellent color density was obtained.

"Comparative example: Paint A having the same formulation as in the example was applied to one side of the same base paper as the base paper used in the example, at a coating amount of 1.5 g/n ( The same type of embossing was applied to obtain coated paper for printing having an uneven surface.

When offset printing was performed on the uneven surface of the coated paper for printing having an uneven surface obtained as described above, the printed surface had an unsatisfactory color density.

As described above, the color density of the printed surface of the example and the printed surface of the comparative example was measured, and the results are shown in the following table, indicating that the printing effect of the coated paper for printing having an uneven surface of the present invention is extremely excellent. That is clear.

Claims (1)

[Claims] (1) Paint is applied to the embossed surface of the base paper almost along the unevenness of the embossment, and the paint-applied surface is
A coated paper for printing, characterized in that a smooth curved surface is formed from the convex part to the inner surface of the concave part, and the depth of the embossed concave part of the base paper is almost maintained. (2) The coated paper for printing according to claim (1), wherein the average depth of the recesses of the embossing applied to the base paper is 15 μm or more. (3) Emboss the base paper with an average depth of 15 μm or more, and then use an air knife coater to apply paint almost along the unevenness of the embossment, creating a smooth curved surface from the convex part to the inner surface of the concave part. A method for producing coated paper for printing, comprising forming a coated surface.