JPS5949060B2 - Airless spray nozzle tip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an airless spray nozzle tip that provides a uniform coating thickness.

Conventionally, in airless painting, development has focused on increasing the discharge capacity and widening the pattern width in order to efficiently coat large areas and coat high viscosity paints. However, the application of coatings to surfaces that are limited to small scales has not yet been fully developed.

Generally, when painting with an airless sprayer, the amount of paint discharged is adjusted so that the thickness of the paint film is naturally thinner in the areas that are overcoated, in order to ensure smooth application.

If we illustrate a cross section of this coating perpendicular to the direction of travel of the spray gun, emphasizing the height direction, the spray pattern distribution will be as shown in Figure 1A, and in the case of repeated coatings, Figure 1B become that way. In the figure, 1 is a cross section of the coating film, and 2 is the base of the construction surface. However, when coating within a certain limited width, it may be more convenient for the cross section 12 of the coating to be rectangular or trapezoidal as shown in FIG. 2.

For example, such a uniform film thickness is desirable for road sign lines or traffic paint. In the case of applying traffic paint, the conventional coating film (Fig. 1) has the following problems.

1. After painting, the film is thick in the center, so drying in this area is delayed.

″2 The film on both ends is thin, so it wears out quickly.

3. When distributing glass beads after painting, the glass beads at both ends do not stick well.

4 The finish is not beautiful.

etc. In order to solve these problems, the present inventors researched airless coating conditions that would form a uniform coating thickness, and found that by adjusting the shape of the nozzle tip, a rectangular or trapezoidal cross-section can be created. We succeeded in forming a coating film with the following properties using airless spraying.

In other words, by changing the shape of the discharge hole of the nozzle tip, the shape of the cut, and the shape of the space (back mold) where the paint accumulates on the back side of the discharge hole, it is possible to form a coating film with a substantially uniform thickness. This invention will be explained using drawings.

5. FIG. 3 is a diagram of a conventional nozzle tip with a standard shape, where A is a cross-sectional view and B is a plan view.

This is made by cutting the top part of the back mold into a V shape, which has a bell-shaped space extending inside the main body 4, and the discharge hole 3 is in the shape of a double-sided convex lens with pointed ends (see Fig. 10). In contrast, the back mold of the airless nozzle used in the present invention is the fourth
As shown in the figure, the inner side of the main body 4 has the shapes of a back mold B with a hemispherical tip and a bell-shaped opening 5, and a back mold C with a bell-shaped opening 6.A in Fig. 4 is the conventional type. It is something.

The shape of the cutting force cut for cutting the tops 7 of back dies B and C in combination with this type of back die is a U-shaped cut as shown in Fig. 5b and a brush-shaped cut as shown in C, and a is a conventional type. cut, d
The inverted trapezoidal cut of ``e'' and the pencil cut of ``e'' are reference examples of cut shapes. The above back mold B, C and the shape of the cut B, C
The shapes of the discharge holes cut by the combination of the above include an oval shape close to a rectangle in which both pointed ends of a double-convex lens shape are shaved off so as to be rounded, and a hexagonal shape surrounded by an arc.

Figure 6 shows the shape of the discharge hole cut by the combination of back mold B and cut B, which is an oval discharge hole 8, and the cross section of the coating film obtained using this is shown in the figure on the right. .

In this case, the coating is formed flat. Figure 7 shows the shape of the discharge hole formed by the combination of the back mold B and the brush-shaped cut C.
A nearly hexagonal discharge hole 9 is formed with both ends in the long axis direction having a △ shape, and the coating film obtained using the discharge hole 9 is almost flat as shown in the figure on the right. FIG. 8 shows the shape of the discharge hole formed by the combination of the back mold C and the U-shaped cut b, and an elongated circular discharge hole 10 is formed.

The cross section of the coating film obtained using this method is flat, although both ends are slightly higher, as shown in the figure on the right. Figure 9 shows the shape of the discharge hole formed by the combination of the back mold C and the brush-shaped cut C, resulting in a nearly hexagonal discharge hole 11, and the coating film is flat regardless of the width of the pattern, as shown in the figure on the right. is formed.

In the shape of the above-mentioned discharge hole, an ellipse is defined by an elongated circle similar to an oval, two opposing circular arcs with equal and large curvature, and four opposing circular arcs with equal and small curvature. Including hexagonal shapes.

Figures 10, 11, and 12 are comparative examples with the present invention, and Figure 10 is a combination of the conventional back die A and V cut a, and the first
Figure 1 shows the combination of back mold A and pencil cut e, and Figure 12 shows the shape of the discharge hole for each combination of back mold B and V cut a, and the cross-sectional shape of the coated film depending on the shape of the discharge hole. As shown, the shape of the discharge hole is almost the same as that of conventional type 3,
The cross section of the coating film becomes thinner at both ends. As described above, the present invention provides a nozzle tip for airless spray, which has a back mold shape with a bell-shaped or bell-shaped opening space for collecting paint inside the main body, and a U-shaped cut or a U-shaped cut at the top of the back mold. Since the paint discharge hole is cut into a brush-shaped cross-sectional shape and has an approximate oval shape including an oval shape, when applying traffic paint using the nozzle tip of this invention, the width of the painting pattern is As a result, a coating film with an average coating thickness and a uniform thickness can be formed, and a uniform coating film is obtained, which improves drying properties, and also makes wear uniform, resulting in a longer service life.

Furthermore, when glass beads are sprinkled after painting, the coating film thickness is flat and uniform, so the beads adhere well and create a beautiful finish. Furthermore, application using the nozzle tip of the present invention can be applied in addition to traffic paint, such as markings of a certain width, painting that is applied uniformly in one application, or applying something like an adhesive in the form of a band. It can be used in many cases and is extremely useful.

Next, examples of coating using the nozzle tip of the present invention will be given.
Painting Example 1 Painting was carried out using Traffic Paint (JISK549l for room temperature) and the nozzle tip shown in Figure 8 under the following conditions.

Properties of paint used Viscosity (20℃) 82KU Residue after heating 72% Specific gravity (20℃)
℃) 1.40 whiteness
89 (diffuse reflectance) drying property
8 minute painting conditions paint pressure
110kg/Anl nozzle diameter
0.96mm pattern width
15c0) Construction speed
5km/h Paint film thickness (wet)
As a result of the 300μ coating, road marking lines with a uniform and beautiful finish were obtained.

Painting example 2: Use heated truck paint according to Japan Highway Public Corporation standards.

Heat the paint using the nozzle tip shown in Figure 9,
As a result of airless spray painting under the following conditions, road marking lines with a uniform and beautiful finish were obtained. Furthermore, as a result of scattering glass beads (defined in JISK549L) during the spray pattern, the glass beads were evenly fixed,
Road marking lines with good durability and nighttime reflective effect were obtained.

[Brief explanation of the drawing]

Figure 1 shows a cross-sectional view of the paint film produced by conventional airless painting. Figure A is a cross-sectional view of the paint film based on the spray pattern distribution for one coat, and Figure B shows the first and second coats for successive coats. Figure 2 is a cross-sectional view of the paint film showing the state of repeated coating, Figure 3 is a diagram showing a conventional nozzle tip, Figure A is a cross-sectional view, and Figure B is a plan view. Figure 4 is a sectional view showing the shape of the back of each nozzle tip used in the present invention, Figure 5 is a diagram showing several types of cut shapes of the tip, and Figures 6 to 9 are cross-sectional views showing the shape of the back mold of each nozzle tip used in the present invention. FIG. 10 is a plan view showing the shape of the discharge hole of the nozzle tip and a sectional view of the coating film related to the shape of the discharge hole. FIG. FIG. 12 is a comparative example showing a plan view of the discharge hole formed by the back mold of the nozzle tip and a cut shape, and a sectional view of the coating film. 4...Main body, 5...Bell shape, 6...
...Hanging bell shape, 7...Top, 8,9,10,
11...Paint discharge hole, b...U-shaped cut, c...Brush-shaped cut.

Claims (1)

[Claims] 1. In the nozzle tip for airless spray, a back mold with a hemispherical tip and a bell-shaped or bell-shaped opening on the inside of the main body, and a U-shaped cut or a brush-shaped cut on the top of the hemispherical shape, including an oval shape. A nozzle tip for airless spray that has a nearly oval-shaped paint discharge hole.