JPH0560995B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applied to interior and exterior wall materials of buildings, etc.
The present invention relates to a method for coating an uneven base material having an uneven three-dimensional pattern.

<Prior Art> In recent years, decorative boards whose surfaces have been made uneven by means such as embossing have been widely used in order to give aesthetic appearance to the interior and exterior walls of buildings. Such uneven decorative laminates, that is, flat substrates with uneven surfaces, are usually coated with an aggregate-containing aqueous emulsion to give the surface more decorative properties and to make the base material more durable. Paint is applied. As a coating method for such an uneven base material surface, a coating method using a spray or a flow coater that can perform continuous coating is considered.

<Problems to be solved by the invention> However, in the painting method using a flow coater, there are many cases where there is a shadow (blind spot) in a part of the concave part of the base material, and that part is not painted.
There were problems that significantly reduced the product value.

Therefore, air spray or airless spray painting methods are mainly used because they can coat the entire surface. However, as is well known, the spray coating method is unsanitary as it causes a lot of paint mist to splatter during coating, and the coating efficiency is also extremely low, so it cannot be said to be a desirable method from the viewpoint of resource saving.

In view of the above-mentioned current situation, the inventor of the present invention has realized that there is no splashing of paint mist due to the flow coater,
Furthermore, the inventors have discovered a method that can uniformly coat the entire surface while taking advantage of the good coating efficiency, and have arrived at the present invention.

<Means for solving the problem> That is, the present invention continuously conveys a flat base material with an uneven surface by a conveyor for 50 to 120 m/s.
In the method of coating the aggregate-containing water-based emulsion paint on the substrate with a flow coater while transferring the paint at a speed of min. Painting of uneven substrates characterized by using paint (at room temperature) and maintaining the paint outlet of the flow coater at a height distance of approximately 140 to 250 mm from the surface of the substrate. It is about the method.

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

FIG. 1 is a longitudinal cross-sectional view in the conveyor traveling direction of a state coated by the flow coater of the present invention.

In the drawings, 1 is a flow coater head, 2 is a paint flow outlet (slit), 3 is a conveyor, a is an aggregate-containing water-based emulsion paint, a' is a paint curtain, A is a coating film, and B is an uneven base material. It is.

In the present invention, coating is carried out in the same manner as the conventional method except for changing the aggregate-containing aqueous emulsion paint described below and the height distance from the substrate surface of the paint outlet of the flow coater. In other words, the uneven base material B is continuously moved at a speed of 50 to 120 m/min.
While being transferred by the conveyor 3, the paint falls from the paint outlet 2 of the flow coater with a slit width of approximately 0.7 to 1.5 mm, and the paint is applied to the substrate surface B by the paint curtain a' formed, with a film thickness of approximately 10 mm. An uneven coating film A of ~1000μ is formed.

The substrate used in the present invention is not particularly limited as long as it is in the form of a plate; specifically, wood substrates such as plywood and hardboard; inorganic substrates such as pulp cement board, foamed concrete board, and asbestos slate board; steel plate , metal base materials such as galvanized steel plates, aluminum plates;
Plastic base materials such as ABS resin molded plates or laminates thereof are representative examples.
After embossing the surface of these base materials or scattering paint on the surface of the base material in a scattered manner, removing or suppressing some of the convex parts of the coating film (i.e., head cutting).
For example, the depth of the recess can be adjusted by
The length and width are approximately 0.5 to 10 mm, and the length and width are approximately 3 to 500 mm. It goes without saying that the surfaces of these base materials may be subjected to appropriate surface treatment, painting, etc. In addition, if necessary, the base material may be heated to 35 to 55℃ immediately before painting.
It may be preheated to a certain degree.

By the way, in conventional painting methods, the paint flow outlet 2 is usually held at a position with a height distance of about 30 to 90 mm from the substrate surface, but at this position, as shown in Fig. Unpainted areas tended to occur in some (side wall) shadow areas b.

Therefore, in the present invention, the height distance is set to 140~
250 mm, and by using an aggregate-containing water-based emulsion paint with a thixotropic coefficient (according to a BM type viscometer) of 2.0 to 6.0 at room temperature, it is possible to coat even the shaded area B, and the entire surface can be coated uniformly. .

If the height distance of the paint flow outlet 2 is shorter than the above-mentioned range, unpainted parts are likely to be left at the bottom of the recess and the shadow part b.On the other hand, if it is too long, the paint is susceptible to the effects of wind, etc., resulting in curtain breakage, etc. Both are undesirable because they tend to occur and the entire surface cannot be coated uniformly.

Furthermore, the aggregate-containing water-based emulsion paint used in the present invention can utilize paint constituents that are normally used in ricin paints and the like. Namely, acrylic resin emulsion consisting of emulsion resin, water and optionally various coloring pigments, extender pigments, additives, etc., vinyl acetate-acrylic resin emulsion, ethylene-acrylic resin emulsion, styrene-butadiene resin emulsion, acetic acid. Emulsion paints such as vinyl resin emulsion, vinyl acetate-vinyl chloride resin emulsion, and epoxy resin emulsion, silica sand with an average particle size of approximately 0.1 to 1.5 mm, cold water sand, fired glaze particles, glass beads, quartz powder, plastic powder, etc. It is an aggregate-containing paint with a solid content of approximately 50 to 90% by weight, in which approximately 20 to 50% by weight of aggregate is blended in the total solid content of the paint.In particular, in the present invention, the thixometry coefficient of the paint is 2.0 to 6.0.
Type and amount of resin: type of aggregate,
The size, amount, solid content of the paint, etc. are adjusted as appropriate.

In addition, if the thixometry coefficient is smaller than the above range, curtain breakage will occur, and sagging will occur at the convex portions.On the other hand, if it is too large, there will be insufficient fluidity when it falls on the base material surface, resulting in only uncoated areas. Also, it is not preferable because the leveling of the painted surface becomes worse. The thixometry coefficient is calculated by setting the rotor #4 of the BM type viscometer, inserting it into the paint, giving it rotation, and measuring the viscosity (poise) at two rotational speeds of 6.rpm and 60rpm. The value is [(viscosity at 6r.pm)/(viscosity at 60r.pm)].

In addition, the aggregate-containing water-based emulsion paint used in the present invention has a viscosity of 20 to 50 seconds (Food Cup #4/
(20℃) is suitable.

As described above, in the present invention, by using a paint with a thixometry coefficient of 2.0 to 6.0 as an aggregate-containing water-based emulsion paint, we can maintain instantaneous fluidity when it falls onto the substrate surface (thixotropic fluid is a physical (When force is applied, it instantaneously exhibits Newtonian fluid-like viscosity.), while improving flow into the recesses, it also improves the film thickness retention (covering) of the convex parts,
Furthermore, by keeping the paint flow port of the flow coater at a height distance of approximately 140 to 250 mm from the base material surface, the speed at which the paint flows down to the base material surface is increased, and the flow into the recesses is improved. The entire surface can be painted evenly.

<Effects of the Invention> The method of the present invention enables hygienic painting with no splashes of paint mist etc. using a flow coater.
In addition, it has good coating efficiency and can save resources, and while taking advantage of the characteristics of continuous high-speed coating, it is also possible to coat the shadows of the concave parts of uneven substrates, so it has the characteristic that it can be coated uniformly on the entire surface. This is a practically innovative method.

The present invention will be explained in more detail below using examples.

Example 1 An uneven asbestos slate board embossed into a rectangular embossed pattern (size 1150 x 3000 x 10 mm; average depth of recesses approximately 2.5 mm, average diameter approximately 10 x 500 mm) was conveyed at a speed of 75 m/min. Flow coater while continuously transferring (slit length 1200mm, slit width 0.75mm; distance between slit and substrate 150mm)
230 g of silica sand-containing water-based acrylic resin emulsion paint (viscosity [food cup #4/20°C] 33 seconds; thixometry coefficient 5; paint solids content 76%; silica sand No. 7; silica sand content 38%) was applied onto the substrate. /m ² and allowed to air dry for one day.

The base material of the coated base material was not visible at all even in the recesses, and the entire surface was coated. The stability of the curtain was also good.

Similar good results were also obtained when the distance between the slit and the base material was changed to 230 mm.

Comparative Example 1 Coating was carried out in the same manner as in Example 1 except that the distance between the flow coater slit and the substrate was 90 mm, which is the same as in the conventional method.

The resulting coating film had scattered spots of unpainted spots in the recessed areas.

Comparative Example 2 Painting was carried out in the same manner as in Example 1 except that a water-based acrylic resin emulsion paint containing silica sand with a thixometry coefficient of 1 was used.

Even in the paint film obtained when forming a normal paint curtain with no curtain breaks, a paint film with aggregate was not formed in the sloped part of the recess (part b in Figure 2), and the curtain was also defective. The coating was not stable and uniform over the entire surface.

Comparative Example 3 Painting was carried out in the same manner as in Example 1 except that a water-based acrylic resin emulsion paint containing silica sand with a thixometry coefficient of 7 was used.

Even in the coating film obtained when forming a normal paint curtain with no curtain breaks, linear unpainted parts were observed in the recesses, and the curtain also broke intermittently, and the entire surface was not evenly coated.

Example 2 An uneven wood cement board embossed with a rectangular embossed pattern (size 1150 x 3000 x 10 mm; average depth of recesses approximately 2.5 mm, average diameter approximately 10 x 500 mm) was conveyed at a speed of 80 m/min. Flow coater while continuously transferring (slit length 1200mm, slit width 0.75mm; distance between slit and substrate 150mm)
A water-based bier acetate resin emulsion paint containing silica sand (viscosity 33 seconds; thixometry coefficient 3; paint solids content 72)
%; silica sand No. 7; silica sand content 38%) on the base material.
It was applied at a rate of 230 g/m ² and air-dried for one day.

The base material of the coated base material was not visible at all even in the recesses, and the entire surface was coated. The stability of the curtain was also good.

Comparative Example 4 In Example 2, the distance between the slit and the base material was set to 270
Painting was carried out in the same manner except that the thickness was changed to mm.

Although the resulting coating film was also formed on the side walls of the recess, it was not uniformly coated due to curtain breakage.

Example 3 An uneven wood cement board embossed with a rectangular embossed pattern (size 1150 x 3000 x 20 mm; average depth of recesses approximately 5 mm, average diameter approximately 10 x 300 mm) was conveyed at a speed of 70 m/min. A flow coater (slit length 1200 mm, slit width 0.8 mm; distance between slit and substrate 220 mm) was used to continuously transfer the water-based vinyl acetate resin emulsion paint containing silica sand (viscosity 40 seconds; thixometry coefficient 5; paint solids content). 78%;
Silica sand No. 7 (silica sand content 38%) was placed on the base material at a
It was applied at a rate of g/m ² and air-dried for one day.

The base material of the coated base material was not visible at all even in the recesses, and the entire surface was coated. The stability of the curtain was also good.

Comparative Example 5 In Example 3, the distance between the slit and the base material was 90 mm.
Painting was carried out in the same manner except for the following. The resulting coating film had continuous uncoated areas in the sloped concave portions (section b in Figure 2).

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view in the conveyor traveling direction of a state coated by the flow coater of the present invention.
FIG. 2 is a longitudinal sectional view showing the state of coating film formation by a conventional flow coater. 1... Flow coater head, 2... Paint outlet, 3... Conveyor, a... Paint, a'... Paint curtain, A... Paint film, B... Base material, b... Shadow part of recess. .

Claims (1)

[Claims] 1 While conveying a flat base material with an uneven surface continuously at a speed of 50 to 120 m/min on a conveyor, paint an aggregate-containing water-based emulsion paint onto the base material using a flow coater. In the method of
(at room temperature), and the flow coater's paint outlet is placed at a height of approximately
A method for painting an uneven base material, which is characterized by painting while holding the base material at a position of 140 to 250 mm.