Nozzle for applying foamed adhesives

Abstract

The present invention relates to a nozzle for applying adhesives comprising an assembly consisting of a nozzle body (1), in which at least one outlet duct (2) of the adhesive to be applied is defined in a position between 0° and 180° with respect to at least one inlet duct (3) of the adhesive from a dosing module (4) to which said nozzle body (1) is coupled and through which the adhesive is fed. The end (5) of the dosing module (4) has a central closing stem (8) for closing the dosing module (4) with a conical end that penetrates the inlet duct (3) in a closed position of the passage of adhesive from the dosing module (4) to the outlet duct (2).

Description

[0001] DESCRIPTION

[0002] NOZZLE FOR APPLICATION OF FOAMED ADHESIVES

[0003] Technical sector

[0004] The present invention relates to the application of hot-melt adhesive and, particularly, foamed adhesives, proposing an application nozzle for this use, which has been developed with structural characteristics that improve the functional conditions of behavior in use.

[0005] State of the art

[0006] Foam adhesive systems are increasingly being used in the packaging sector. These systems feature larger adhesive beads applied compared to non-foam adhesives. This means that when the surfaces to be bonded are pressed, the adhesive is distributed over a larger surface area. This improves adhesion and allows for a reduction in the amount of adhesive used, resulting in savings in raw materials for applications.

[0007] On the other hand, the temperature at which foamed adhesives work is lower, so less energy is required to adapt the adhesive to the application conditions.

[0008] A very common type of application when using foamed adhesives is the application of the adhesive using right-angle nozzles, meaning that the inlet duct, through a dosing module, and the outlet duct of the adhesive, through the body of the application nozzle, are at 90°, so that the applicator is used in a "lying down" position, which allows adaptation to small spaces where application may be necessary.

[0009] Examples of right-angle nozzles for applying adhesives include those described in US4469248 and US5887757, which describe nozzles of this type that allow for advantageous use under the aforementioned conditions. However, the conventional design of such nozzles has the disadvantage that the volume of the adhesive circulation channels inside the nozzle body is very large, such that the residual adhesive remaining in these channels between applications swells due to the presence of air bubbles, causing the residual adhesive to overflow through the nozzle's outlet. This is a problem because it drastically reduces the precision of the adhesive dosage in the next application.

[0010] This is because the applicator assembly is structured with a ball closure between the dosing module and the application nozzle, with a long delivery conduit leading to the adhesive outlet conduit through the body of the application nozzle behind said closure.

[0011] For this reason, it is necessary to have a screw on the back that can be removed for cleaning the interior, but due to the difficulty of machining the threaded housing, this screw does not reach the intersection of the conduit that comes from the dosing module, leaving therefore in that area an empty space of considerable volume, which is prone to the accumulation of residual adhesive.

[0012] Therefore, having application nozzles with reduced volume internal channels would provide great advantages, because foamed adhesive could be used in applications where it cannot currently be used, and therefore a problem to be solved would be to obtain a right-angle application nozzle, with a smaller volume of internal channels than in current nozzles.

[0013] Object of the invention

[0014] In accordance with the present invention, a nozzle for applying adhesives is proposed, which has been developed according to the right angle typology, that is, with the adhesive supply conduit and the application outlet conduit located at 90°, but with structural characteristics that allow the volume of the internal conduits to be reduced, avoiding the problem caused by residual adhesive in conventional nozzles for use with foamed adhesives.

[0015] This nozzle object of the invention comprises a nozzle body in which at least one outlet duct for the adhesive to be applied is defined, said outlet duct being in position with an angle between 0 o and 180°, preferably at 90°, with respect to at least one adhesive delivery conduit from a dosing module to which said nozzle body is coupled, and through which the adhesive is fed, with the particularity, in this case, that at the end of the dosing module there is a central rod for closing the dosing module with a conical end that penetrates the delivery conduit in a position to close the passage of adhesive from the dosing module to the outlet conduit.

[0016] This design leaves very little space between the passage closure and the nozzle body's outlet duct, which minimizes the amount of residual adhesive that can remain when the applicator is used.

[0017] Furthermore, by placing the end of the dosing module close to the outlet duct through the nozzle body, the nozzle assembly can be structured with a smaller size, which helps to avoid the inconvenience of a cold spot in the circulation of the adhesive to the application outlet.

[0018] This solution also eliminates the need to install a screw on the back of the application body, which was necessary for internal cleaning in prior-technology solutions, as the duct's clearance is minimal, making this cleaning operation unnecessary. However, the use of such a screw for certain applications is not ruled out.

[0019] The nozzle object of the invention will be configured for the application of foamed adhesives, being in this type of applications where the greatest problems may arise.

[0020] According to a characteristic of the invention, the end of the dosing module has a conical shape corresponding to a conical geometry of the nozzle body with which it is coupled.

[0021] Preferably, the coupling surface between the nozzle body and the dosing module is configured to make contact and generate a seal.

[0022] According to another aspect of the invention, the nozzle body has two or more outlet ducts located between 0 o and 180° with respect to the adhesive inlet duct from the dosing module, with an angle between them, which provides greater versatility in application. Preferably, the adhesive outlet ducts are arranged on different planes, i.e., at different heights relative to the adhesive inlet duct.

[0023] According to another feature of the invention, the adhesive delivery duct comprises an extension in the nozzle body, said extension having the same diameter as the adhesive outlet duct. This reduces the size of the duct through which the adhesive passes, and it is also a continuous section that prevents blockages. It is not ruled out that the extension may have a larger or smaller diameter than the adhesive outlet duct, depending on the characteristics of the application.

[0024] According to another feature of the invention, the nozzle body comprises a chamfer on the front portion of the nozzle body close to the outlet opening of the adhesive outlet duct. This helps prevent any adhesive residue that may remain outside the body from sliding away from the nozzle outlet openings, thus preventing them from becoming clogged.

[0025] To enhance this effect, the nozzle is designed to include a hydrophobic coating. This way, the adhesive will form "balls" and not stick to the nozzle. Preferably, the coating will ensure low surface tension, for example, less than 30 dynes, so that the adhesive doesn't remain on the surface and form droplets.

[0026] Additionally, the nozzle object of the invention preferably comprises a nozzle adapter that can be connected to the dosing module, preferably by means of threading, and which, together with an external nut, facilitates the coupling between the nozzle body and the dosing module. Said adapter and / or the nozzle body will be made of a metallic material with a high thermal conductivity greater than 40 W / mK.

[0027] This configuration facilitates maintenance and assembly. Additionally, the nozzle adapter allows the nozzle body to be oriented, preventing the central stem from changing position when closing, and the outer nut allows the outlet holes to be rotated to position them without affecting the central stem.

[0028] According to another feature of the invention, the outlet diameter of the adhesive outlet duct is less than 1 mm, thereby achieving optimal application quality. According to another feature of the invention, the adhesive outlet duct comprises an extension tube in its outlet orifice. This configuration prevents the adhesive from expanding and spreading or dripping down the nozzle body. This ensures that the adhesive remains in the outlet orifice so that the next application of adhesive can carry it away without dripping.

[0029] According to another aspect of the invention, the adhesive outlet duct is formed by an insert that can be removably attached to the nozzle body. This configuration allows adaptation to different applications by simply changing the nozzle insert and facilitates cleaning.

[0030] Finally, according to an alternative embodiment of the invention, the end of the dosing module and the nozzle body are formed as a single unit. This reduces the length of the adhesive delivery duct, which is mostly covered by the end of the central closing rod, thereby reducing the amount of adhesive that may remain in said duct after application.

[0031] For all these reasons, the nozzle object of the invention has very advantageous characteristics for use in the application of foamed adhesives, acquiring a life of its own and preferential character with respect to conventional nozzles for said application.

[0032] Description of the figures

[0033] Figure 1 shows a longitudinal sectional view of an embodiment of the nozzle object of the invention.

[0034] Figure 2 shows a cross-sectional view of an alternative embodiment with a nozzle with two outlets.

[0035] Figure 3 shows a longitudinal sectional view of an alternative example of the nozzle object of the invention.

[0036] Figures 4 and 5 show a profile view of an exemplary embodiment in which the outlet nozzles are located at different heights. The hidden lines in Figure 5 are shown for better understanding of the positioning of the nozzle outlets. Figure 6 shows a longitudinal sectional view of an exemplary embodiment of the nozzle with a locking screw.

[0037] Figure 7 shows a longitudinal sectional view of an embodiment of the nozzle with the nozzle body integrated into the end of the dispenser.

[0038] Figure 8 shows a longitudinal sectional view of an embodiment of the nozzle with an extension tube in the outlet opening of the outlet duct of the nozzle body.

[0039] Detailed description of the invention

[0040] The object of the invention relates to a nozzle for applying adhesives, with structural characteristics that make it suitable for use with foamed adhesives, comprising a nozzle body (1), in which at least one outlet duct (2) of the adhesive to be applied is defined, which in the embodiment shown in the figures is positioned at 90° with respect to an inlet duct (3) of the adhesive from a dosing module (4), through which the adhesive is fed.

[0041] In said component assembly of the nozzle, according to the embodiment shown in the figures, the dosing module (4) is arranged in such a way that it is coupled to the nozzle body (1), preferably with a watertight seal, said dosing module (4) having, according to a practical embodiment, an end (5) formed in a conical shape, with which it fits into the nozzle body (1), coupling to it, and reducing the volume of the adhesive delivery conduit (3) with respect to the state of the art.

[0042] In this arrangement, there is a smaller volume of space between the adhesive delivery conduit (3) from the dosing module (4) and the adhesive outlet conduit (2) through the nozzle body (1), so that very little residual adhesive can be retained in this space during use of the applicator. Furthermore, the adhesive passageway in the dosing module (4) is closed by means of a closing rod (8) comprising a conical end (5) that is inserted into said conduit (3) that starts from the end (5) of the dosing module (4) where the passageway is closed. This configuration further reduces the volume of the conduit (3). The conduit (3) for the adhesive to arrive at the vertical channel according to the figures is understood to begin where the adhesive passageway is closed at the end (5) of the dosing module (4) and the end of said conduit (3) that meets the adhesive outlet conduit (2).

[0043] According to figure 2, the possibility is also provided for the nozzle body (1) to have two or more outlet ducts (2) located between 0 o and 180°, preferably at 90°, with respect to the adhesive arrival conduit (3) from the dosing module (4), which does not alter the concept of the invention in the sense that in the nozzle body (1) there is at least one adhesive outlet conduit (2) in position between 0 o and 180°, preferably at 90°, with respect to the adhesive arrival duct (3) from the dosing module (4).

[0044] In Figure 3 it can also be seen that, for an alternative embodiment, the adhesive inlet duct (3) has a section (3.1) that forms part of the end (5) of the dosing module, and an extension (3.2) that forms part of the nozzle body (1). This extension (3.2) comprises a reduction in diameter with respect to the section (3.1) of the adhesive inlet duct (3), said diameter being uniform with the adhesive outlet duct (2).

[0045] According to an alternative practical embodiment, as can be seen in figures 1 and 3, the nozzle body (1) comprises in the outlet part of the ducts (2) a chamfer (10) that limits in the front part the length of the nozzle body (1) close to the outlet orifice of said adhesive outlet ducts (2), favoring that any adhesive residue that could remain outside the nozzle body slides and moves away from the nozzle outlet orifices.

[0046] This configuration can be complemented with a hydrophobic coating applied to the nozzle that will help with sliding and prevent the adhesive from accumulating and blocking the outlet.

[0047] In figures 4 and 5, you can see an example of an embodiment with two outlet ducts (2), arranged at different heights in the adhesive arrival duct (3).

[0048] Furthermore, as can be seen in figures 1 and 6, facing the rear of the adhesive outlet duct (2) in some applications, a closing screw (7) can be arranged, which can be removed to clean the inside of the nozzle body (1), said screw (7) being provided in extension of its end with a non-threaded section, which occupies the free space left at the intersection between the outlet duct (2) that extends through the nozzle body (1) and the inlet duct (3) from the dosing module (4), whereby there is practically no space in which residual adhesive can be retained when using the applicator.

[0049] According to the preferred embodiment shown in figures 1 to 6, the nozzle comprises a nozzle adapter (9) that can be fixed to the dosing module (4), and which in turn maintains the connection between the body (4.1) of the dosing module and the end (5) of said dosing module (4) which in this embodiment are kept separated into two elements, and, on the other hand, serves as a support for an external nut (11) that maintains the coupling between the dosing module (4) and the nozzle body (1). In this way, the nozzle body (1) can be rotated without affecting the central rod (8).

[0050] In the practical embodiment shown in figure 7, it can be seen how in this case the nozzle body (1) is integrated into the conical end (5) of the dosing module (4) forming a monoblock, so that the volume of the adhesive arrival duct (3) is reduced to a minimum.

[0051] According to a practical embodiment of the invention, as can be seen in Figure 8, the outlet orifice of the adhesive outlet duct (2) may comprise an extension tube (2.2).

Claims

CLAIMS 1.- Nozzle for applying adhesives, comprising an assembly formed by a nozzle body (1), in which at least one outlet duct (2) of the adhesive to be applied is defined, in a position between 0 o and 180° with respect to at least one conduit (3) for the arrival of the adhesive from a dosing module (4) to which said nozzle body (1) is coupled, and through which the adhesive is fed, characterized in that at the end (5) of the dosing module (4) there is a central rod (8) for closing the dosing module (4) with a conical end that penetrates the arrival conduit (3) in a position for closing the passage of adhesive from the dosing module (4) to the outlet conduit (2). 2.- Nozzle for applying adhesives, according to the first claim, in which the adhesive may be foamed. 3.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the adhesive outlet conduit (2) to be applied is in a position at 90° with respect to the adhesive arrival conduit (3) from a dosing module (4). 4.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the end (5) of the dosing module has a conical shape in correspondence with a conical geometry of the nozzle body (1) with which it is coupled. 5.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the coupling surface (6) between the nozzle body (1) and the dosing module (4) is configured to make contact and generate a seal. 6.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the nozzle body (1) has two or more outlet ducts (2) located between 0 o and 180° with respect to the adhesive arrival duct (3) from the dosing module (4), and with an angle between them. 7.- Nozzle for applying adhesives, according to the previous claim, where the adhesive outlet ducts (2) are arranged in different planes. 8.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the adhesive delivery duct (3) comprises an extension (3.2) in the nozzle body (1), said extension (3.2) being of the same diameter as the diameter of the adhesive outlet duct (2). 9.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the nozzle body (1) comprises a chamfer (10) in the front part of the nozzle body (1) close to the outlet orifice of the adhesive outlet duct (2). 10.- Nozzle for applying adhesives, according to any one of the preceding claims, comprising a hydrophobic coating at the outlet of the outlet duct (2). 11.- Nozzle for applying adhesives, according to any one of the preceding claims, comprising a nozzle adapter (9) connectable to the dosing module (4) which together with an external nut (11) couples the nozzle body (1) to the dosing module (4). 12.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the outlet diameter of the adhesive outlet duct (2) is less than 1 mm. 13.- Nozzle for applying adhesives, according to any one of the preceding claims, wherein the adhesive outlet conduit (2) comprises an extension tube (2.2) in its outlet orifice. 14.- Nozzle for applying adhesives, according to any one of claims 1 to 13, wherein the adhesive outlet duct (2) is formed by an insert (2.1) that can be removably attached to the nozzle body (1). 15.- Nozzle for applying adhesives, according to any one of the preceding claims, where the end (5) of the dosing module (4) and the nozzle body (1) form a single block.

Images