WO2022271005A1

WO2022271005A1 - Method for forming and securing a gasket on a mounting cup

Info

Publication number: WO2022271005A1
Application number: PCT/MY2021/050114
Authority: WO
Inventors: Yoke En Ong
Original assignee: Samurai 2K Aerosol Sdn. Bhd.
Priority date: 2021-06-24
Filing date: 2021-11-30
Publication date: 2022-12-29
Also published as: CN117500733A

Abstract

The invention provides a method for forming and securing an outer gasket (400) around a mounting cup (200) of an aerosol valve, comprising the steps of depositing an adhesion layer (400) on a groove (201) formed at the mounting cup (200) where the outer gasket (400) is to be moulded on using an adhesion deposition unit, and injecting a molten material using an injection moulding machine to form the outer gasket based on a shape of a gasket mould and the groove (201). The adhesion layer (300) bonds the outer gasket (400) to the groove (201) as the outer gasket (400) is moulded for the outer gasket (400) to be affixed to the groove (201) of the mounting cup (200).

Description

METHOD FOR FORMING AND SECURING A GASKET ON A MOUNTING CUP

FIELD OF INVENTION

The invention relates to forming and securing a gasket on a mounting cup. More particularly, the invention relates to a method for forming and securing an outer gasket to a mounting cup of an aerosol valve through the deposition of an adhesion layer and the injection moulding of the outer gasket.

BACKGROUND OF THE INVENTION

An aerosol spray comprises of an aerosol can and an aerosol valve, wherein the aerosol can is a can that stores contents such as a payload and propellant, while the aerosol valve seals the aerosol can. The aerosol valve may comprise a mounting cup surrounding one end of a housing where a stem having a valve is inserted. The payload may be, but not limited to, thinned paint lacquer, or any form of liquids or fine powders. Similarly, the propellant may be, but not limited to, air or gaseous hydrocarbons. The propellant is typically stored in the aerosol can at high pressure, so that it can force the payload to be dispensed when the valve of the aerosol valve is opened.

The manufacturing of an aerosol spray involves the joining of the aerosol valve to the aerosol can through a crimping process, for the contents within the aerosol to be sealed in an air-tight and leak-proof manner. Hence, the mounting cup of an aerosol valve typically has a gasket to form a seal between the aerosol valve and the aerosol can.

However, certain steps in the manufacturing of the aerosol spray may cause defects in the final product. Among them is the step of the performing crimping process, whereby the force introduced by the crimping machine causes certain components of the aerosol valve, such as an outer gasket, to deviate from its original position. As a result, the aerosol valve may not be properly crimped to the aerosol body, and the aerosol spray may be defective. Another is the step of filling the propellant, whereby as the propellant is filled into the aerosol can at high pressure, the sudden difference in pressure may induce a force that causes the outer gasket to deviate from its original position.

The defects caused by the outer gasket deviating from its original position include insufficient pressurization of the payload due to propellant leakage, which causes the payload to be unable to be dispensed, or dispensed in a runny manner. As such, the lifespan of the product is substantially reduced, and the aerosol spray would be discarded before the payload is completely used up, thereby creating wastage as well.

Certain players in the aerosol industry have attempted to circumvent the aforementioned problem by providing solutions to ensure the outer gasket of the aerosol valve remains fixed at its original position throughout the aerosol spray manufacturing process. Among the solutions, in particular, is to make the outer gasket thicker and have a semi-circular cross-section shape so that it can fully accommodate the groove of the mounting cup where it is to be placed.

Moreover, there are a few disclosed technologies relating to the formation of a gasket around a mounting cup of an aerosol valve through injection moulding. Among them is JP2626464B2, which discloses methods to form a thermoplastic resin gasket of a uniform shape highly accurately in the curled part of a mounting cup and to improve productivity. A mounting cup is placed in a mould for use in injection moulding, and a gasket formed between the grooved portions of the mounting cup and the mould.

Another disclosed technology is EP2853506B1, which discloses a method for manufacturing an aerosol valve assembly comprising a mounting cup having a dome and a crimping body, a valve body, a rod, a spring member for holding the rod in the closed position in the absence of external stress, an inner seal to be placed in the dome of the cup and an outer seal to be placed in the crimping edge of the cup. The invention also relates to an aerosol valve assembly and a moulding process for carrying out the method. In particular, the external gasket is formed through injection moulding on the face of the mounting cup.

Even so, making the aerosol gasket thicker and in a semi-circular shape does not fully guarantee that the outer gasket is prevented from deviating from its original position during the step of performing crimping process and the step of filling the propellant. The formation of the outer gasket on the mounting cup through injection moulding processes as suggested in JP2626464B2 and EP2853506B1 only ensures the correct positioning of the outer gasket when the outer gasket is first formed, or moulded, on the groove of the mounting cup. They fail to disclose means for the outer gasket to be held securely on the mounting cup throughout the aerosol spray manufacturing process.

Accordingly, it is desirable to have an outer gasket formed and secured to a mounting cup of an aerosol valve through the deposition of an adhesion layer and the injection moulding of the outer gasket to ensure that the outer gasket does not deviate from its original position throughout the aerosol spray manufacturing process.

SUMMARY OF INVENTION

The main objective of the invention is to provide a method to form an outer gasket on a mounting cup of an aerosol valve and secure it in its original position on the mounting cup throughout the aerosol spray manufacturing process. To achieve this objective, the method provided by the invention involves the application of an adhesion layer and the injection moulding of the outer gasket around the mounting cup. As a result of the invention, the injection moulded outer gasket is secured in a fixed position and will not deviate from its original position during steps in the aerosol spray manufacturing process especially during the step of crimping and the step of filling of the propellant.

The invention provides a method for forming and securing an outer gasket around a mounting cup of an aerosol valve, comprising the steps of depositing an adhesion layer on a groove formed at the mounting cup where the outer gasket is to be formed on using an adhesion deposition unit, and injecting a molten material using an injection moulding machine to form the outer gasket based on a shape of a gasket mould and the groove. The adhesion layer bonds the outer gasket to the groove as the outer gasket is formed, or moulded, for the outer gasket to be affixed to the groove of the mounting cup.

Preferably, in regards to the method, the groove is formed around an underside of a rim of the mounting cup. Preferably as well, the adhesion layer is in fluid form.

Preferably, in regards to the method, the method further comprises the step of allowing the adhesion layer to dry. Preferably as well, the adhesion layer is allowed to dry for 5 to 10 minutes.

Preferably, in regards to the method, the outer gasket is formed through an overmoulding process wherein the gasket mould encompasses at least a position adjacent to the groove for the molten material to be injected into a cavity in between the groove and the gasket mould. Preferably as well, the molten material is thermoplastic, thermoset, or elastomer material.

The invention further provides an aerosol valve comprising a mounting cup surrounding one end of a housing where a stem is inserted. The mounting cup has an outer gasket formed through a method previously described.

One skilled in the art will readily appreciate that the invention is well adapted to carry out the objects and obtain the ends and advantages mentioned, as well as those inherent therein. The embodiments described herein are not intended as limitations on the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

To facilitate an understanding of the invention, there is illustrated in the accompanying drawing the preferred embodiments from an inspection of which when considered in connection with the following description, the invention, its construction and operation and many of its advantages would be readily understood and appreciated.

FIG. 1 is a flowchart illustrating the steps of the method of the present invention.

FIG. 2 is a diagram illustrating the cross-sectional view of the mounting cup, together with the adhesion layer and the injection moulded outer gasket.

FIG. 3 is a diagram illustrating the cross-sectional view of the assembled aerosol spray, which includes the aerosol valve comprising the mounting cup and stem, and the aerosol can; the mounting cup being an end product of the method of the proposed invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method to form and secure a gasket, more specifically the outer gasket 400, around a mounting cup 200 of an aerosol valve through the application of an adhesion layer and an injection moulding of the outer gasket 400. The invention may also be presented in different embodiments with common elements. According to the concept of the invention, the method involves the step of depositing an adhesion layer 300 on the mounting cup 200 where the outer gasket 400 is to be formed or moulded, and the step of injection moulding by encasing the mounting cup 200 into a gasket mould and injecting a molten material to form the outer gasket 400. The invention will now be described in greater detail, by way of example, with reference to the figures.

FIG. l is a flowchart that illustrates the process flow of the current invention. The first step is step 101, whereby a bare mounting cup 200 of an aerosol valve is prepared from a prior step in the aerosol spray manufacturing process. In the second step, step 102, the mounting cup 200 is placed onto an adhesion deposition unit for an adhesion layer 300 to be deposited on a groove 201 on the mounting cup 200. The adhesion layer 300 is preferably left to dry prior to the following step. In the third step, step 103, the mounting cup 200 is enclosed within a gasket mould of an injection moulding machine. In the fourth step, step 104, molten material is injected into the gasket mould, by the components of the injection moulding machine to form the outer gasket 400. In the final step, step 105, the mounting cup 200, which now further comprises the moulded outer gasket 400 that is bonded to it through the adhesion layer 300, is released from the gasket mould. This mounting cup 200 may then be passed to other steps in the aerosol spray manufacturing process.

FIG. 2 illustrates the cross-sectional view of the resulting mounting cup 200 as per step 105. It shows the mounting cup 200, the adhesion layer 300 that has been deposited on groove 201 of the mounting cup 200, and the outer gasket 400 that was formed through injection moulding. It should be noted that the adhesion layer 300 in FIG. 2 has been drawn in an exaggerated manner and is in actual fact a very thin layer.

With reference to FIG. 1 and FIG. 2, during step 101, the bare mounting cup 200 that is to be used in the method of the present invention may be manufactured by conventional means. In particular, the mounting cup 200 is preferably composed of metallic material, such as aluminium alloys, stainless steel or the likes, so that it may withstand an internally pressurized environment when it is eventually assembled into an aerosol spray during the aerosol spray manufacturing process. It should be noted that the preferred embodiment of the mounting cup 200 has a circular outline, and hence the injection moulded outer gasket 400 shall have a final shape of an annulus. However, the mounting cup 200 need not be limited to such an outline, and may have a shape of a square or an oblong, which shall influence the final shape of the injection moulded outer gasket 400 as well.

With reference to FIG. 1 and FIG. 2, during step 102, the mounting cup 200 is mounted onto an adhesion deposition unit for an adhesion layer 300 is deposited on the groove 201 of the mounting cup 200, the groove 201 defined to be located at an underside of a rim of the mounting cup 200. Preferably, the adhesion layer 300 is in the form of an adhesion promoter, in which after deposition on a surface, shall be able to form a dry and non-sticky layer on the surface that promotes adhesion upon drying or curing, thereby reducing the messiness of the workplace. The adhesion promoter used in this method was specifically chosen so that a chemical bond is formed is between the groove 201 of the mounting cup 200 and the injection moulded outer gasket 400. Preferably as well, the adhesion layer 300 is solvent-based, or diluted with solvent, so that it may be deposited to the surface of the groove 201 with equal smoothness and consistency by a nozzle of the adhesion deposition unit.

The way in which the adhesion layer 300 may be deposited on the groove 201 by the nozzle of the adhesion deposition unit may be by configuring the mounting cup 200 to rotate in a circular manner, for its groove 201 to rotate with respect to the nozzle that deposits the adhesion layer 300. Alternatively, the nozzle of the adhesion deposition unit nozzle may be configured to rotate adjacently to the groove 201 and deposit the adhesion layer 300.

As it is preferable that the adhesion layer 300 is in the form of an adhesion promoter, upon deposition of the adhesion layer 300 on the groove 201 of the mounting cup 200, the mounting cup 200 is left to air dry for the adhesion layer 300 to be dried or cured. The drying may be done under room temperature or in an oven with elevated temperature. Preferably, the adhesion layer 300 dries or cures within 5 to 10 minutes after being deposited on the groove 201 of the mounting cup 200.

With reference to FIG. 1 and FIG. 2, during step 103, the mounting cup 200 having the adhesion layer 300 is encased within a gasket mould of an injection moulding machine. The gasket mould is preferably a reusable 2-part metal mould. Within the gasket mould, there is at least a position adjacent to the groove 201 of the mounting cup 200 for a molten material to be injected into a cavity in between the groove 201 of the mounting cup 200 and the gasket mould, for an outer gasket 400 to be formed on the groove 201 of the mounting cup 200 which currently has the adhesion layer 300.

With reference to FIG. 1 and FIG. 2, during step 104, molten material is injected into the gasket mould, by a screw press of the injection moulding machine. The molten material may be of rubber, thermoplastic, thermoset, or elastomer material, which are suitable material for forming a durable outer gasket 400. The injection moulding machine may further comprise a storage compartment to store a plurality of pellets that correspond to the molten material, and a set of heating elements to melt the pellets into the molten material. As the molten material flows into the gasket mould and occupies the entirety of the cavity in between the groove 201 of the mounting cup 200 and the gasket mould, the outer gasket 400 is formed. Since the mounting cup 200 preferably has a circular outline, the outer gasket 400 would have a shape of an annulus. In addition to that, the outer gasket 400 conforms to the surface of the groove 201 as it is injection moulded, thus the outer gasket 400 may have a C-shaped or D-shaped cross-section.

The type of injection moulding, which has been described to form, or mould, the outer gasket 400 in the method of the proposed invention, is overmoulding. However, it should be noted that other types of injection moulding may be used as well, such as two-shot injection moulding. With reference to FIG. 1 and FIG. 2, during step 105, the mounting cup 200, which now further comprises the moulded outer gasket 400, is cooled within the mould before being released from the mould. The outer gasket 400 is now chemically bonded to the groove 201 of the mounting cup 200 through the adhesion layer 300, and preferably permanently affixed to the groove 201 at a fixed position. This mounting cup 200 may then be passed on to other steps in the aerosol spray manufacturing process.

It is possible to deposit the adhesion layer 300 after the formation, or moulding, of the outer gasket 400 through injection moulding. However, in doing so, the adhesion layer 300 deposited may be uneven, and this may cause the adhesion layer 300 to dry too slowly for a chemical bond to be formed between the outer gasket 400 and mounting cup 200. Moreover, it will be required that the outer gasket 400 be not disturbed when the adhesion layer 300 is still undergoing drying or curing. If the adhesion layer 300 is not dried or cured completely, movements may be induced upon the outer gasket 400 and the adhesion layer 300 to smudge onto other unintended areas of the assembled aerosol spray. Thus, the outer gasket 400 to not perform its sealing functionality properly, and the smudges may also cause the appearance of the assembled aerosol spray to be unappealing and perceived to be lacking in quality. The method of the proposed invention resolved all of the aforementioned problems.

FIG. 3 illustrates the relative positioning of the mounting cup 200 produced from step 105 within an assembled aerosol spray. It includes the aerosol valve that comprises the mounting cup 200 and a stem 600, and the aerosol can 500. The mounting cup 200 surrounds one end of a housing for a stem 600 to be inserted. Further illustrated is that the groove 201 of the mounting cup 200 is substantially located adjacent to the rims of the dome portion 501 of the aerosol can 500 so that the outer gasket 400 seals the orifice of the dome portion 501.

Ultimately, the method proposed by the present invention forms and secures an outer gasket 400 in a fixed position. Thus the outer gasket 400 will not deviate from its original position, which is the groove 201 of the mounting cup 200, throughout the aerosol manufacturing process especially during the step of crimping and the step of filling of the propellant. Moreover, this method provides a significantly time-efficient and cleaner appearance of the assembled aerosol spray.

The present disclosure includes as contained in the appended claims, as well as that of the foregoing description. Although this invention has been described in its preferred form with a degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangements of parts may be resorted to without departing from the scope of the invention.

Claims

1. A method for forming and securing an outer gasket (400) around a mounting cup (200) of an aerosol valve, comprising the steps of depositing an adhesion layer (400) on a groove (201) formed at the mounting cup (200) where the outer gasket (400) is to be moulded on using an adhesion deposition unit; and injecting a molten material using an injection moulding machine to form the outer gasket based on a shape of a gasket mould and the groove (201); wherein the adhesion layer (300) bonds the outer gasket (400) to the groove (201) as the outer gasket (400) is moulded for the outer gasket (400) to be affixed to the groove (201) of the mounting cup (200).

2. The method according to claim 1, wherein the groove (201) is formed around an underside of a rim of the mounting cup (200).

3. The method according to claim 1 or 2, wherein the adhesion layer (400) is in fluid form.

4. The method according to any one of the preceding claims, further comprising the step of allowing the adhesion layer (400) to dry.

5. The method according to claim 4, wherein the adhesion layer (400) is allowed to dry for 5 to 10 minutes.

6. The method according to any one of the preceding claims, wherein the outer gasket (400) is formed through an overmoulding process wherein the gasket mould encompasses at least a position adjacent to the groove (201) for the molten material to be injected into a cavity in between the groove (201) and the gasket mould.

7. The method according to any one of the preceding claims, wherein the molten material is thermoplastic, thermoset, or elastomer material.

8. An aerosol valve comprising a mounting cup (200) surrounding one end of a housing where a stem (600) is inserted; wherein the mounting cup (200) has an outer gasket (400) formed through a method according to any one of claims 1 to 7.