JPS61249747A - Reinforced paper for bottom label - 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 (Field of Industrial Application) The present invention relates to a resin-reinforced paper with a relatively low basis weight, and in particular provides a reinforced paper that is suitable for printing on one surface and is intended for use as decorative base paper for building materials. It is something.

(Prior art) Methods for reinforcing resins to improve the weak interpaper strength, which is a drawback of conventional paper, can be roughly divided into two types: internal addition of resin during paper making, and resin impregnation after paper making. It is done by two methods.

(Problems to be Solved by the Invention) The method of internally adding resin has the advantage that it can strengthen the paper almost uniformly regardless of its basis weight, and does not require a separate process for 1 reinforcement. Due to the poor yield of resin at the time, it was difficult to sufficiently achieve the purpose of reinforcing the paper gap.On the other hand, the method of resin impregnation after papermaking generally depends on the method of dipping into the impregnating solution, so it is difficult to sufficiently achieve the purpose of reinforcing the paper gap. The purpose of reinforcing the paper spacing can be achieved by impregnating it with the paper, but in general, post-processing on the surface 1, such as printing suitability.

Not only is there a problem with ink adhesion, but also 1. In terms of processes, the productivity in the impregnation and drying steps is significantly lower than the general speed of paper making, etc., and in practice, the cost is extremely limited.

The present invention solves and eliminates the problems of conventional products as described above.
・The surface is resistant to post-processing such as printing and top coating.
``The purpose of this invention is to provide a resin-reinforced paper that has appropriate black lubricity and ink adhesion, is comparable in physical properties to conventional bone-made paper, and has good productivity.

(Means for solving the problem) Sunarichi 4 Invention 0 Summary is - Relatively low basis weight 0 A highly permeable base paper that does not contain pigments is coated with a thermally crosslinkable resin from one side of the base paper and penetrates to the back side. After this, a resin containing a large amount of titanium oxide pigment is applied to the front or back surface to increase the hiding power of the paper, and the surface smoothness of the resin layer is further improved by calender pressing.

The contents will be explained in detail below.

The base paper used in the present invention is non-size paper or low-size paper with a basis weight of 50 g/m' or less, does not contain pigment, and has a Klemm water absorbency (JI-3', 981141') of 17.
From the viewpoint of permeability, etc., it is preferable that the bleaching rate be at least 100% per minute.

The impregnated resin generally contributes to paper reinforcement,
A thermally crosslinkable resin and a roll coat containing the same,
Items that can be coated by commonly used coating methods such as kiss coating, gravure coating, knife coating, air knife coating, etc. 1. For example, acrylic, rubber latex, polyamide, melamine, urea, phenolic resin and modified products thereof, which have crosslinkable functional groups; Alternatively, an aqueous solution of a thermoplastic polymer containing the same can be used. The appropriate concentration is between 25 and 35% by weight from the viewpoint of permeability and maintenance of interpaper strength.

If base paper is impregnated with these resins using the ordinary doping method, it is impossible to avoid the disadvantages in terms of the process as described above, and when ordinary base paper is impregnated with resins using the coating method, It is difficult to obtain sufficient penetration. Furthermore, since no pigment is added to the base paper used in the present invention for permeability reasons, it does not have the concealing properties of a resin-impregnated paper. Therefore, in order to compensate for this, a mixture with a thermoplastic resin containing a large amount of titanium oxide or a thermally crosslinkable resin whose main component is a thermoplastic resin is used.
A material that can be coated by a commonly used coating method such as roll coating, kiss coating, gravure coating, knife coating, or air knife coating is applied. Furthermore, as a result of various experiments, the amount of titanium oxide to be added is 100~ROOP.
HR(Pigmentper Hundred Re5
in) is necessary, and the application amount is 7 to 17 j;l/
It was concluded that m'' dry is appropriate.

=3- The surface of the paper coated with a thermoplastic resin is smoothed using a calender to obtain reinforced paper with good printability.

The step of impregnating the thermocrosslinkable resin and the step of applying the thermoplastic resin may be performed continuously with a drying step in between, or may be performed in separate steps.

(Function) Since the present invention has the above-described configuration, the resin very easily penetrates into the base paper, and the resin reaches the back surface even with a normal coating method. Furthermore, the resin layer, which is mainly composed of a thermoplastic resin containing a large amount of titanium oxide, not only increases the hiding power, but also has extremely good surface smoothness by calendar pressing, and also has excellent printing ink receptivity.

(Effects of the Invention) - The entire paper layer is uniformly impregnated with a large amount of thermally crosslinkable resin, resulting in excellent interpaper strength.

A thermoplastic resin layer containing a large amount of titanium oxide is formed on the 0 surface, and has excellent hiding properties, printability, and printing ink receptivity.

(Example) Polyacrylic emulsion, polyvinyl acetate emulsion, melamine formaldehyde resin, and its curing agent were added to the surface of unsized paper (Klemm water absorbency 2 1/min) with a basis weight of 409/m at a solid content ratio of 45: A resin composition containing a ratio of 45:10:0.3 was adjusted to a concentration of 60%, and applied at a solid content of 16 g/d using an air knife coater at 150'C.
After drying for 30 seconds, the same resin composition containing a polyacrylic emulsion, titanium oxide, and extender pigment in a solid content ratio of Ji5:100Nia0 was applied to the coated surface using an air knife coater. Apply 15g/m' in minutes,
After further drying at 160°C for 20 seconds and then smoothing the surface by calender press.

A wood grain pattern was printed using a gravure printing machine using cellulose ink, and the same acrylic urethane top coat resin was printed using a gravure printing machine and dried at 170°C for 30 seconds to produce a decorative sheet.

This decorative sheet was press-attached to a particle board using a urea/formaldehyde adhesive to produce a decorative board.

In terms of physical properties, this decorative board did not peel off at each of the top coat layer, ink layer, paper layer, adhesive layer, or at their interfaces in a peel test using cellophane tape.

The result was a decorative board with extremely good resistance to cellophane peeling, and in terms of design, the decorative board had a deep, high-class feel that could not be achieved with conventional resin-impregnated paper. For comparison, Table 1 shows the results of comparing the surface smoothness and Sellotape resistance of the resin-reinforced paper of each company's Tobuzuke method and the resin-reinforced paper of the present invention.
Shown below.

Table 1

Claims (1)

[Claims] A pigment-free base paper with a basis weight of 50 g/m^2 or less and a Klemm water absorption of 17 mm/min or more is impregnated with a thermo-crosslinkable resin from one side to the back, and either side is mainly made of a thermoplastic resin. A resin composition containing 100 to 300 parts by weight of titanium oxide per 100 parts by weight of resin has a solid content of 7 g.
/m^2 or more reinforced paper for decorative paper.