JPS5861276A - Production of enameled plate - Google Patents

Abstract

PURPOSE:To obtain a large quantity of enameled blackboards of good performances provided with dark lines by sticking a transfer sheet formed with patterns of the dark lines and a full solid layer on a steel plate for enamel formed with an under glaze layer by thermocompression bonding. CONSTITUTION:A strippable varnish layer 2 is provided on the surface of a release sheet 1 according to need, and patterns 3 for dark lines are printed thereon with ink contg. glaze for enamel of a dark line color. A full solid layer 4 is formed thereon with ink contg. glaze for enamel controlled to the surface color of the blackboard and an adhesive varnish layer 5 is provided over the entire surface thereof to manufacture a transfer sheet. After the surface of a steel plate 6 for enamel which is a base material is applied with pretreatments, under glaze 7 is coated on said surface and is calcined. If necessary, an under glaze layer 8 for transfer is coated and is calcined. The transfer sheet is superposed on the enamel plate 9 by directing the layer 5 toward said plate and both are pressurized under heating to transfer and stick the layer 5, the layer 4, the patterns 3 and the layer 2 to one body. The sheet 1 is removed, and the entire part is calcined to form the layer 4 and the patterns 5 in one body with the layer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing enamel writing boards such as enamel blackboards and whiteboards, and particularly to a method for easily manufacturing enamel writing boards with dark lines. Conventional enamel blackboards or whiteboards (hereinafter simply referred to as blackboards) have been widely used due to their excellent erasability and durability. However, products with dark lines on their surfaces have a lot of latent demand because they are easy to write on, but the reality is that they are not very popular because they are expensive. . The present invention provides a method for manufacturing enamel blackboards with dark lines at low cost in large quantities, which has no difference in performance from conventional products.

Conventionally, when manufacturing enameled blackboard surface materials with dark lines, the general method is to apply a lower glaze and an upper glaze to the surface of a pretreated steel plate for enamel, and then fire each once, and then apply a screen. A dark line was printed and then fired once to finish. The disadvantage of this method is that continuous operation is not possible because the screen printing method is sheet-fed printing. The cost increases because the number of firings increases by one. If the firing of enamel is done on a continuous line, it is possible to install a printing means in the middle of the line and print dark lines continuously, but in this case as well, in addition to the final firing,
Usually, the speed of the enamel firing line is extremely slow compared to normal printing, making printing itself difficult.

The present invention solves the above-mentioned drawbacks and provides a method for economically producing an enameled blackboard surface material with dark lines by the same number of firings as conventional products without dark lines.

The present invention will be explained in detail below with reference to the drawings.

First, as shown in Figure 1, after providing a release varnish layer (2) on the surface of the release sheet (1) as necessary, a dark line pattern (3) is applied using ink containing a dark line enamel glaze. Print, then form a peta layer (4) on the entire surface with ink containing an enamel glaze adjusted to the surface color of the blackboard, apply an adhesive varnish layer (5) on the entire surface of the vermilion color, dry and transfer. Get a sheet.

As the release sheet, known release paper, release film, etc. can be used. The ink for dark line printing uses a glaze with the same composition or similar melting temperature as the glaze used for the entire solid layer, and a small amount of pigment to give the color tone of the dark line to the kneaded powder. Use with binder and solvent added.

The ink for the entire surface is made by adding an organic binder, a solvent, etc. to a powder obtained by grinding a frit of a desired color according to the intended use, such as a blackboard or whiteboard.

Adhesive varnish is applied for the purpose of adhering the ink layer of the enamel glaze to the enamel plate, and uses a thermoplastic resin that softens with heat.

Release varnish is effective in improving transferability, but
Not necessarily necessary.

The binder in the release varnish, adhesive varnish, and ink must completely decompose and scatter during firing, and acrylic resins, cellulose resins, etc. are used. Furthermore, there are no particular restrictions on the printing method, and gravure printing, screen printing, etc. can be used. Regarding the formation of the peta layer, any method such as a gravure printing method, a reverse roll coater, a knife coater, etc. can be selected.

Next, in Fig. 2, the steel plate for enamel (6) serving as the base material is subjected to necessary pretreatment such as degreasing and nickel treatment, and then underglaze is applied to the front and back surfaces and fired. Transfer base gg 5 Apply the wax layer (8) and bake.

If the transfer base is a white board, the black color of the lower glaze may have a negative effect on the product depending on the color tone, so this is done to prevent this, and also to adjust the transfer surface. In some cases, this transfer base layer may be omitted.

Next, the transfer process will be described.

In the case of sheet transfer, a hot press machine may be used for transfer, or in the case of continuous operation, a roll transfer machine equipped with a heated rubber roll may be used. In each case, as shown in Fig. 3, the transfer sheet is placed on the enamel plate (9) with the adhesive varnish side facing the enamel plate, and the adhesive varnish layer (5) is removed by heating and pressing.
Full surface solid layer (4), dark line pattern (3), peeling varnish layer (2)
) are integrally transferred onto an enamel plate, and then, after removing the mold release sheet (1), the whole is fired to integrate the entire solid layer and the dark line pattern with the lower glaze layer. In addition, during the firing process, the adhesive varnish, release varnish, solid layer on the entire surface, and organic binder in the dark line pattern are decomposed by heat and scattered.

〔Example〕

By gravure printing method on the surface of release sheet.

An acrylic resin-based release varnish was applied using a 60 μm plate. Next, a dark line pattern on the blackboard was printed using ink with the following composition.

Next, apply 10% of the following composition over it using a knife coater.
It was applied to a thickness of 0μ.

Next, a cellulose and resin-based adhesive varnish was coated with a mesh roll coater at a rate of 51/2 to obtain a transfer sheet.

After degreasing, washing with water, and nickel treatment a 051-thick steel plate coil for enameling, a top glaze slip was applied by spraying, and the coil was fired at 850° C. for 5 minutes. The temperature of the enamel plate is 130℃
When cooled to 780°C, the transfer sheet was placed on the lower glaze coated surface of the steel plate coil using a rubber roll heated to 150°C, and the pattern etc. was transferred by pressure and the release sheet was removed. After firing for a minute, a coiled enamel blackboard surface material with dark lines was obtained. Note that the transfer speed was 5 m/min.

The blackboard obtained in the manner described above is completely similar in appearance to the conventional two-step product, and has no inferiority in terms of wear resistance, erasability, etc. As an effect of the method of the present invention, a blackboard with dark lines can be manufactured with the same number of firing times as a conventional blackboard without dark lines, so it can be supplied in large quantities at a lower cost than conventional blackboards with dark lines. Furthermore, according to the method of the present invention, if several types of transfer sheets are prepared in advance, it is possible to easily change the manufactured item by simply replacing the transfer sheets, which is extremely efficient. In addition, the transfer sheet itself can be manufactured at a low cost, which is advantageous in terms of cost, since there is no waste of expensive glaze compared to conventional direct spraying. Furthermore, since continuous production is possible, blackboards with dark lines of any length can be manufactured.

[Brief explanation of the drawing]

The drawings are schematic diagrams illustrating an example of the process of the method of the present invention, in which FIG. 1 is a cross-sectional view showing the structure of a transfer sheet, FIG. 2 is a cross-sectional view of a steel plate for enameling provided with a lower glaze layer, and FIG. The figures each show a schematic diagram showing the transfer process. (1) Release sheet (2) Release varnish layer (3
)...Dark line □Design (4)...Full surface solid layer (5)...Adhesive varnish layer (6)...Steel plate for enamel (7)...Underglaze (8)...Transfer Base enamel layer (
9) Enamel plate patent applicant Toppan Printing Co., Ltd.

Claims (1)

[Claims] A method for producing a dark lined enamel plate comprising the following steps. ■After providing a release varnish layer on the surface of the release sheet as necessary, a dark line pattern is printed using ink containing a pure dark color enamel glaze, and then printed on top of it according to the intended use, such as a blackboard or whiteboard. A process of forming a peta layer on the entire surface with ink containing an enamel glaze adjusted to the desired color, and then forming an adhesive varnish layer on the entire surface to produce a transfer sheet. ■The process of applying the glaze for the lower glaze layer after applying the necessary pretreatment to the surface of the steel plate for enameling to form the lower glaze layer. ■Process of forming a transfer base enamel layer on the lower glaze layer as necessary. (2) A step of bonding the transfer sheet onto the lower glaze layer or the transfer base enamel layer on the surface of the steel plate by heating and pressing. ■The process of removing the release sheet and baking to integrate the dark line pattern and the entire peta layer with the lower glaze layer or the transfer base enamel layer.