JPH077771U - Nozzle tip for coating - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object to provide a nozzle tip for coating a high-viscosity liquid, which has a uniform coating thickness distribution during coating. A coating nozzle used for airless coating of a high-viscosity liquid, characterized in that an outer shape of a liquid discharge portion is a spherical shape, and a slit in one direction is formed in the spherical shape portion as a discharge port. The slit has a constant width, the shape of the inner wall surface corresponding to the inner end of the liquid discharge portion at the tip of the liquid conducting path is conical or spherical, or along the liquid conducting path. The cross-section in one direction has a substantially triangular shape, while the cross-section in a direction orthogonal to the one direction has a substantially semi-circular shape.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a high-viscosity liquid coating nozzle tip, and more particularly to a coating nozzle tip having a uniform coating film thickness distribution during coating.

[0002]

[Prior art]

 When airless coating of a high-viscosity liquid such as a sealing material under pressure, a nozzle tip for coating has been used in various ways. It is desired that the coating film thickness of the applied sealing material be as uniform as possible for this coating nozzle tip, and one having a structure shown in FIG. 7 has already been proposed as an example. In the example shown in (a), a conical recess 20 is provided on the back surface, a slit 21 reaching the recess 20 from the front surface is provided, and a chamfer 22 is provided at the ridge angle of the opening of the slit 21. . Further, as shown in (b) in place of the slit 21, a structure having a V groove 23 is also proposed.

A high-viscosity liquid such as a sealing material is supplied to the nozzle tip having such a structure under pressure, and the sealing material is discharged from the tip of the slit 21 or the V groove 23 to obtain a coating film having a constant thickness. It is intended.

[0004]

[Problems to be solved by the device]

 However, the conventional nozzle tip as described above has a problem that the coating film thickness distribution in the coating region becomes non-uniform. As shown in FIG. 8, an example of this coating film thickness distribution is shown in FIG. 8 (a). In the case of a nozzle chip having a chamfered portion 22 in the opening of slit 21 as shown in FIG. In the case where the V groove 23 is provided as shown in the previous figure (b), the central portion tends to be depressed as shown in the figure (b).

Therefore, it goes without saying that the coating operation using such a nozzle tip consumes an excessive amount of material in excess of the required amount in order to obtain a uniform coating film thickness distribution, which is a problem in terms of economy. Of. Further, since the coating thickness distribution is not uniform in the coating area, there is a problem in appearance after coating. The inventors of the present invention conducted extensive studies on this problem, and found that such non-uniformity of the coating film thickness is mainly affected by the outer shape of the nozzle tip, leading to the completion of the present invention. It was And the said subject is solved by the following means.

[0006]

[Means for Solving the Problems]

 As described above, an object of the present invention is to provide a nozzle tip for coating a high-viscosity liquid, which has a uniform coating thickness distribution during coating. The present invention, which has solved the above-mentioned problems, is a coating nozzle tip used for airless coating of high-viscosity liquid, in which the outer shape of the liquid ejection portion is spherical, and a unidirectional slit is formed in the spherical portion as the ejection port. It is characterized in that the slit has a constant width, or the inner wall surface at the tip of the liquid guide passage and corresponding to the inner portion of the liquid discharge portion has a conical shape or a spherical shape. It is effective to have a substantially triangular shape in a sectional view in one direction along the liquid conducting path, and a substantially semicircular shape in a sectional view in a direction orthogonal to the one direction.

[0007]

[Action]

 In the coating nozzle tip of the present invention, the above problems can be solved by the following actions using the above means. First, the first effect is obtained by forming the outer shape of the liquid ejecting portion into a spherical shape and forming a slit having a constant width in one direction as needed in the spherical portion as the ejection port. This is a function of making the distance in contact with the flow path wall almost the same while the liquid is discharged, and reducing the space dependence of the discharge resistance received by the liquid. The second effect is that the inner wall surface, which is the tip of the liquid passage and corresponds to the inner portion of the liquid discharge portion, has a conical or spherical shape, or has a cross section in one direction along the liquid passage. Some of them can be obtained by making the shape substantially triangular when viewed, and by making it substantially semicircular when viewed in a cross section in the direction orthogonal to the one direction. This is a function of more optimally adjusting the discharge resistance, that is, the distance in contact with the flow path wall while the liquid is discharged. These two actions are embodied by the following examples, and a coating nozzle tip having an extremely uniform coating film thickness distribution can be obtained.

[0008]

【Example】

 FIG. 1 is a perspective view showing a specific embodiment of the present invention. In the illustrated example, a spherical liquid discharger 3 is provided at the tip of a substantially cylindrical body 2 as the nozzle 1, and the liquid discharger 3 has a constant width in one direction and in the depth direction as a discharge port. The linear slit 4 is provided. Reference numeral 5 is a flat portion for a spanner lock. 2A shows the sectional structure in the direction of the slit 4 of the nozzle tip 1, and FIG. 2B shows the sectional structure in the direction orthogonal to the direction of (A). In the example shown in the figure, the liquid conducting path 6 penetrates through the center of the main body, and the inner wall surface 7 corresponding to the inner portion of the liquid discharging section 3 at the tip of the liquid conducting path 6 has a conical shape. Is. In such a structure, the distance between the inner wall surface 7 and the outer wall surface 8 of the liquid ejecting portion 3, that is, the wall thickness of the liquid ejecting portion 3 is substantially constant at any position in the inner wall surface 7. . Therefore, as explained in the section of action, as a result of the location dependence of the fluid resistance of the liquid passing through the slits 4 being reduced, the uniformity of the coating pattern is improved and the coating thickness distribution within the coating area becomes constant. Of.

The liquid ejection mode by the nozzle tip 1 is shown in FIGS. 3A and 3B. First, as shown in (a), the discharge form of the liquid 9 discharged from the liquid discharge part 3 of the present nozzle chip 1 becomes wide, and as described above, it depends on the geometrical elements of the inner and outer wall surfaces of the liquid discharge part 3. Thus, the coating material 10 having a uniform coating film thickness distribution can be obtained. Then, as shown in (b), the nozzle tip 1 is moved in a direction orthogonal to the direction of the slit 4 with respect to the object to be coated 11 while discharging the liquid 9, so that the coating film thickness distribution becomes uniform. The coating material 10 is obtained over a wide area.

As described above, the thickness distribution of the coating film is substantially determined by the geometrical factors on the inner and outer wall surfaces of the liquid ejection portion 3, and the second embodiment is more uniform in coating than the first embodiment. It is proposed to obtain a film thickness distribution. This second embodiment is shown in FIG. 4 as its sectional structure. As (a), the sectional structure in the direction of the slit 4 of the nozzle tip 1 is shown, and as (b), the direction orthogonal to the direction of (a). The cross-sectional structures at are shown respectively. As is clear from the figure, in this example, the shape of the inner wall surface 7 corresponding to the inner portion of the liquid ejection portion 3 is a semicircular shape. In such a structure, by making the inner wall surface 7 and the spherical center of the liquid ejection portion 3 coincide with each other, the wall thickness of the liquid ejection portion 3 becomes constant at any position within the inner wall surface 7. Therefore, it goes without saying that the coating film thickness distribution in the coating region becomes more uniform than in the first embodiment.

Further, a structure combining the above two examples is also possible as a third embodiment. FIG. 5 shows such a third embodiment as its sectional structure. As (a), the sectional structure in the direction of the slit 4 of the nozzle tip 1 is shown as (b) and in the direction orthogonal to the direction of (a). The cross-sectional structures at are respectively shown. In this example, as is clear from the drawing, the shape of the inner wall surface 7 of the liquid ejection portion 3 is triangular in the same direction as the slit 4, and is semicircular in the direction orthogonal thereto.

These three examples are variations of the geometrical elements of the inner wall surface of the liquid ejection portion that affect the coating film thickness distribution of the coating material, and the shape is not limited to this example. Absent. Even if the shape factor of the inner wall surface is constant, the coating thickness distribution varies depending on various conditions such as the type of high-viscosity liquid used and the working environment temperature. It is also effective to change the shape factor of the outer wall surface of the liquid ejection portion as described below in order to cope with such variation in the coating film thickness distribution.

Next, referring to FIG. 6, the change of the geometrical elements on the outer wall surface 8 of the liquid discharge portion will be described by using the example of the conical inner wall surface shown in FIG. In the figure, (a) shows an example in which the coating thickness on both sides of the coating area can be made thicker, and (b) shows an example in which the coating layer thickness on both sides can be made conversely thinner. In (a), the shape of the inner wall surface 7 is made constant, and the spherical radius of the liquid ejection portion 3 is made small so that the thickness of the liquid ejection portion 3 becomes thin on both sides of the inner wall surface 7. Therefore, unlike the case described in the section of the action, the fluid resistance of the liquid passing through the slit 4 becomes small on both sides of the inner wall surface 7, and as a result, the coating thickness on both sides of the coating region becomes thick. On the contrary, (b) is to increase the radius of the spherical surface of the liquid ejecting portion 3 so that the thickness of the liquid ejecting portion 3 becomes thicker on both sides of the inner wall surface 7. Therefore, contrary to the case of (a), the fluid resistance of the liquid passing through the slit 4 becomes large on both sides of the inner wall surface 7, and as a result, the coating thickness on both sides of the coating region becomes thin.

Here, the case where the shape of the inner wall surface 7 is made constant and only the geometrical element of the outer wall surface 8 of the liquid ejection portion 3, that is, the radius of the spherical surface is changed has been described, but as described above, it is the opposite. It is also possible to change the shape of only the inner wall surface 7, or to change both the spherical radius of the liquid ejection portion 3 and the shape of the inner wall surface 7. Further, in the examples of FIGS. 2 and 6, it is also effective to change the distance between the tip and bottom of the conical shape and the tip of the liquid ejecting section 3, the apex angle of the cone, and the like. In addition to this, the outer diameter of the nozzle tip 1 main body, the inner diameter of the liquid conducting path 6, the width of the slit 4, and the like can be changed.

[0015]

[Effect of device]

 As described above, in the coating nozzle tip of the present invention, the following effects can be obtained by the operation described in detail above. First, the outer shape of the liquid ejection portion is made spherical, and slits having a constant width in one direction are formed in the spherical portion as the ejection port in one direction so that the flow passage wall can be ejected while the liquid is ejected. Since the distances in contact with the liquid are almost equal, and the location resistance of the discharge resistance that the liquid receives is reduced, a uniform coating film thickness distribution can be obtained. Next, the shape of the inner wall surface at the tip of the liquid passage corresponding to the inner portion of the liquid discharge portion is made into a conical shape or a spherical shape, or a substantially triangular shape in a cross-sectional view in one direction along the liquid passage. On the other hand, in the cross-sectional view in the direction orthogonal to the one direction, by making the shape semi-circular, the ejection resistance, that is, the distance in contact with the flow path wall during the ejection of the liquid, is more optimal in the ejection region. It can be adjusted. Therefore, it is possible to correct the coating thickness distribution that varies depending on various conditions such as the type of high-viscosity liquid used and the working environment temperature, and to obtain a very uniform coating thickness distribution. As described above, according to the coating nozzle tip of the present invention, an excellent coating thickness distribution can be obtained with an extremely simple structure.

[Brief description of drawings]

FIG. 1 is an explanatory perspective view showing an embodiment of a coating nozzle tip of the present invention.

FIG. 2 is an explanatory sectional view showing an embodiment of the coating nozzle tip of the present invention, in which (a) is a sectional view in the slit direction,
(B) is a cross-sectional view in the direction orthogonal to (A)

3A and 3B are explanatory views showing a discharge form of a coating nozzle tip liquid of the present invention, in which (A) is seen from a direction orthogonal to the slit direction and (B) is seen from the slit direction.

FIG. 4 is an explanatory sectional view showing an embodiment of the coating nozzle tip of the present invention, in which (a) is a sectional view in the slit direction,
(B) is a cross-sectional view in the direction orthogonal to (A)

FIG. 5 is an explanatory sectional view showing an embodiment of the coating nozzle tip of the present invention, in which (a) is a sectional view in the slit direction,
(B) is a cross-sectional view in the direction orthogonal to (A)

FIG. 6 is a cross-sectional explanatory view showing a modified example of the geometrical elements of the liquid discharge portion, in which (a) shows a small spherical radius of the discharge portion;
(B) is a large spherical radius

FIG. 7 is a cross-sectional view for explaining a conventional example of a coating nozzle tip, in which (a) shows a discharge opening as a slit, and (b) shows a discharge groove as a V groove.

8A and 8B are explanatory diagrams showing an example of a coating film thickness distribution when a conventional nozzle tip is used. FIG. 8A shows the nozzle tip of FIG. 7A, and FIG. 8B shows that of FIG. Nozzle tip

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Nozzle tip 2 Main body 3 Liquid discharge part 4, 21 Slit 5 Flat part 6 Liquid conduction path 7 Inner wall surface 8 Outer wall surface 9 Liquid 10 Applied material 11 Applied material 20 Recessed portion 22 Chamfered portion 23 V groove

Claims (5)

[Scope of utility model registration request] 1. A coating nozzle tip used for airless coating of a high-viscosity liquid, wherein a liquid discharging portion has a spherical outer shape, and a unidirectional slit is formed in the spherical portion as a discharging port. Characteristic coating nozzle tip. 2. The coating nozzle tip according to claim 1, wherein the slit has a constant width. 3. The coating nozzle tip according to claim 1, wherein the shape of the inner wall surface corresponding to the inner portion of the liquid discharge portion at the tip of the liquid passage is a conical shape. 4. The coating nozzle tip according to claim 1, wherein the shape of the inner wall surface at the tip of the liquid conducting path and corresponding to the inner portion of the liquid discharge portion is spherical. 5. A shape of an inner wall surface corresponding to an inner portion of the liquid discharge portion at a tip of the liquid conducting path is formed into a substantially triangular shape in a cross sectional view in one direction along the liquid conducting path, and The coating nozzle tip according to claim 1 or 2, wherein the coating nozzle tip has a substantially semicircular shape in a cross-sectional view in a direction orthogonal to one direction.