JPS63190092A - Base paper for decorative sheet - 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 (Industrial Application Field) After the base paper for makeup notebooks of the present invention is printed and coated,
Plywood: 9- Plywood is used for surface decoration of building materials or structural members such as furniture by adhering to base materials such as chicleboard and fiberboard.

(Prior Art) Conventionally, paper-based decorative sheets have been obtained, for example, by printing on base paper with good water absorption, impregnating it with synthetic fibers, drying it, and then applying a resin top coat. In this method, it is necessary to impregnate the paper with a synthetic resin liquid after printing, so when making the base paper, consideration must be given to making it impregnable rather than printable.

However, in general, it is essential to make the paper smooth in order to make it suitable for printing, and to achieve this, during the paper manufacturing process, the paper is fully compressed using a press, calendar, etc.
A smoothing treatment must be carried out, which inevitably increases the density of the paper9, resulting in poor impregnability. In order to maintain the impregnability, the smoothing treatment cannot be performed sufficiently, and as a result, the printability becomes insufficient. This method is called an after-impregnation method because the impregnating process comes after the printing process, but in recent years, a so-called blur impregnation method has been developed in which impregnation is performed before the printing process.

In this method, a decorative sheet Kawahara paper is obtained by making regular paper, impregnating it with a resin liquid, and then performing a smoothing process to impart printability.

(Problems to be Solved by the Invention) In order to increase the interpaper strength of the base paper for cosmetic notebooks obtained by the above-mentioned pre-impregnation method, it is necessary to increase the resin impregnation rate j.
If it is necessary to increase the resin impregnation rate, or if the resin impregnation rate becomes high, it becomes difficult to smooth the surface of the impregnated paper using a press, a calendar, etc., and as a result, sufficient printability cannot be obtained. For this reason, either the resin impregnation rate must be lowered and the paper-to-sheet strength is sacrificed, or the resin impregnation rate is sufficiently high and the printability is sacrificed, or something in between, resulting in insufficient properties in either case. I had no choice but to do it.

(Means for Solving the Problems) The present invention is intended to solve the above-mentioned problems.After the papermaking base paper is sufficiently impregnated with a resin liquid, the entire resin liquid is further coated with a clear coat. By applying smoothing treatment, base paper for cosmetic notebooks can be obtained that satisfies both printability and interpaper strength.

The clear coat according to the present invention has the advantage that it not only improves smoothness easily, but also suppresses the penetration of printing ink into the negative layer, resulting in printing with clear color tones.

The base paper used in the present invention is made from a paper stock made of fibers mainly consisting of natural fibers and, if necessary, chemical fibers, etc., to which pigments, paper strength enhancers, retention aids, and other papermaking aids are added. It is preferably paper-formed using a machine and has a relatively low density so as not to impair impregnability.

In the present invention, as the impregnating resin liquid used as the impregnating agent, an aqueous dispersion of resin or an organic solvent solution is used. (1) As the aqueous dispersion, acrylic emulsion, vinyl acetate emulsion, synthetic rubber emulsion (2) Examples of the organic solvent solution include a mixture of one or more well-selected resin emulsions, or a mixture of this and a thermosetting resin emulsion or an organic solvent solution. Examples include a solution prepared by dissolving one or more resins selected from a mu-based resin or a mixture of these and a thermosetting resin in an organic solvent.

Add this to 100 parts of base paper in terms of solid content of 1° to 10 parts.
Impregnate 0 parts, preferably 15 to 80 parts. When the impregnation rate is less than 10 parts, interpaper strength becomes weak. In order to increase the impregnating rate, it is necessary to increase the concentration of the impregnating solution, but if the concentration is increased to, for example, 50% by weight or more, it becomes difficult for the impregnating agent to penetrate into the base paper, and if the impregnating rate is higher than 100 parts. , the calender effect is low and the smoothness is high, making it difficult to wrinkle.
As a result, printability becomes insufficient.

Next, the resin liquid to be clear coated on the impregnated paper is ■, an acrylic emulsion as an aqueous dispersion.

Vinyl acetate emulsion, N1 Synthetic rubber emulsion, one or more selected resins, or a mixture of these and a thermosetting resin, or acrylic resin and synthetic rubber resin as an organic solvent solution. One or more selected resins or a mixture of these and a thermosetting resin emulsion or solution are used.

The clear coat resin should have a glass transition temperature (Tg) of 0°C or higher, preferably 2°C to prevent blocking.
Preferably, the temperature is 0°C or higher.

The solid content of this is 3g7, 2 to 30 min2, preferably 5
Coat 97m2 to 20 fl/m2. If the coating amount is too small, the smoothness will be insufficient, and conversely, even if the coating amount is increased (to 3097 m2), the effect will not improve, and from economical considerations, 3097 m or more is unnecessary.

In the present invention, a moisture imparting step may be added before the smoothing treatment. By having a moisture content of 6 to 8%, the smoothing process can be carried out smoothly.

A typical method of smoothing processing is supercalender processing. By carrying out this treatment after the above-mentioned resin coating and drying, it is possible to obtain a Peck smoothness of 300 seconds or more, thereby imparting excellent printability.

(Effects of the invention) The base paper for decorative laminate of the present invention has strong interpaper strength because it is impregnated with a sufficient amount of resin, and has high smoothness because the surface is clear-coated with resin and smoothed. , there are fewer white spots during printing, and there is less penetration of printing ink into the paper layer, resulting in printing with vivid colors.

Example 1 A paper stock made of bleached hardwood kraft pulp with a beating degree of 25°S
R was beaten, 5 parts of titanium dioxide, 1 part of red pigment, and 0.01 part of carbon black were added, and a papermaking aid was further added to make a base paper having a basis weight of 5017 parts m2. 100 parts of the obtained base paper was impregnated with 45 parts of 4-reacryl ester emulsion as a solid content, dried, and then coated with 4-rea acrylic ester emulsion with a solid content of 20 fi/m having a Tg of 35°C. The surface of the paper was then smoothed using a Sue G-calender, and a base paper for decorative sheets with a smoothness of 600 seconds and a peel strength of 350.9/15 was obtained. When a wood grain pattern was gravure printed on this, extremely clear and beautiful prints were obtained.

Example 2 A paper stock consisting of 80 parts of bleached hardwood kraft pulp and 20 parts of bleached softwood kraft pulp was beaten to a beating degree of 23°SR, and 20 parts of titanium dioxide and 0.3 parts of red pigment were added.

0.8 part of a yellow pigment was added, and a papermaking aid was further added to make a base paper having a basis weight of 7097 m2.

To 100 parts of the obtained cardboard, polyacrylic acid ester emulsion, methyl methacrylate-butadiene copolymer emulsion, and melamine resin were blended in a solid content ratio of 60:30:10, respectively, to 35 parts solid content. It was impregnated so that

Next, a mixture of a polyacrylic acid ester emulsion at a temperature of 25°C and a melamine resin in a solid ratio of 95:5 was applied at a solid content of 15 g/m2. This was subjected to a humidity conditioning process to add 6% moisture, and was smoothed to a smoothness of 500 seconds using a sous-calender.

The resulting decorative sheet had a peel strength of 320, 9/15.
When a wood grain pattern was gravure printed on this, excellent printed matter was obtained.

Example 3 The papermaking base paper obtained in Example 1 was impregnated with an impregnating agent as shown in Example 2, and further a polyacrylic acid ester emulsion with a Tg of 25°C and a melamine resin were added in solid content. The coating amount shown in Table IK was applied using a mixture in a ratio of 95:5.

This was subjected to a humidity conditioning process to add 8% moisture, and then subjected to sous-carrenoder treatment.

The smoothness, printability, and paper peel strength were as shown in Table 1.

A1: Comparative example *5-level evaluation Good...5 Poor...1 Example 4 For 100 parts of the papermaking base paper obtained in Example 2, an ethyl acetate solution of polyacrylic acid ester was added to a solid content of 70 parts. Then, an ethyl acetate solution of an acrylic acid ester-styrene copolymer with a Tg of 75° C.
g/J coating.

Thereafter, the moisture content was adjusted to 7%, and a super calender was applied to achieve a smoothness of 400 seconds.

The resulting base paper for decorative sheets had a peel strength of 400.9.
/15m+, very strong, and when a wood grain pattern was gravure printed on it, a printed matter with excellent printability was obtained.

Claims (1)

[Scope of Claims] 1. A base paper for decorative sheets made by impregnating a papermaking base paper with a resin liquid and smoothing it, which is characterized in that the base paper is clear coated with a resin liquid containing no pigment after impregnation. 2. The base paper for decorative sheets according to claim 1, which has a peel strength of 200 g/15 mm or more and a smoothness of 300 seconds or more.