EP0507704A1 - Metallic dispensing container with externally seamed valve mounting cup - Google Patents

Abstract

Metallic dispenser container including a neck with a diameter greater than 22 mm on which the valve mounting cup is seamed by external seaming. Between the inside of the neck and the part of the cup which penetrates the neck, a clearance greater than 1 mm is left. <??>Method of manufacture of such a container.

Description

FIELD OF THE INVENTION

The present invention relates to a metal dispenser housing usually called an aerosol in which the dispensing valve is crimped onto the housing. The invention also relates to the method of manufacturing this distributor housing.

STATE OF THE ART

A dispenser box of the aerosol type whatever its size and its nature (metal, glass, plastic, etc.) comprises the box itself which ends at its upper part with a neck and a dispensing valve. The dispensing valve must be fixed on the neck of the housing in such a way that the seal is ensured with respect to the product contained. It is also necessary that the method of fixing the valve does not cause on the external part thereof visible defects by the consumer. The valve itself is located in the center of a cup which fits into the neck of the housing. This cup has an annular outer rim which overlaps the rim of the neck of the housing.

It is known to fix the valve cup by external crimping on the housing with pliers. This is the method shown on Plate 1. It is very commonly used for plastic cases of all sizes and for medium-sized metal cases typically metal cases whose neck has a diameter of about 20 mm. The crimping operation consists in folding the outer skirt 1 of the cup 2 onto the rim 3 of the neck. During the operation the cup 2 is held on the neck by a force exerted from top to bottom. At the end of the operation, the seal 4 is thus compressed.

For larger metal enclosures, typically those whose neck has a diameter of about 25 mm, the process usually used to fix the valve is another process called expansion. In this case the valve cup has a particular shape which is substantially different from the cups of the crimp valves. This method is shown on board 2. The swaging operation consists in deforming the valve cup 5 from the inside to the outside until it is in contact with the inside of the neck 6. At the end the seal 4 is thus compressed.

PROBLEM

• D'une part, au cours de la fabrication, il est nécessaire de changer de pince, éventuellement de machine, et de changer de type de coupelle pour produire successivement des boîtiers distributeurs en plastique et des boîtiers distributeurs métalliques. Ceci entraîne des interruptions dans la chaîne de fabrication et un double stock de matériel de sertissage et de valves.
• D'autre part, le dudgeonnage est une opération délicate plus difficile que le sertissage externe.
• Enfin, les boîtiers distributeurs à coupelle de valve sertie par un sertissage externe présentent en général une meilleure étanchéité que les boîtiers distributeurs à coupelle de valve dudgeonnée.

The manufacture and use of metal dispenser boxes with expanded valves have drawbacks.

• On the one hand, during manufacture, it is necessary to change the clamp, possibly the machine, and to change the type of cup in order to successively produce plastic distributor boxes and metal distributor boxes. This leads to interruptions in the production line and a double stock of crimping equipment and valves.
• On the other hand, swaging is a delicate operation more difficult than external crimping.
• Finally, the valve cup dispenser boxes crimped by an external crimp generally have a better seal than the valve cup dispenser boxes.

To overcome these drawbacks, the applicant has naturally tried to carry out external crimping of the valve cups on large metal housings according to the method conventionally used for medium-sized metal housings and plastic housings.

• * choisir une coupelle de valve dont la partie rentrant dans le col a un diamètre externe sensiblement égal au diamètre interne du col, le diamètre externe de la coupelle de la valve étant cependant légèrement inférieur au diamètre interne du col, typiquement de 0,2 mm, pour faciliter l'introduction
• * déposer sur le rebord du col un joint d'étanchéité annulaire
• * introduire la coupelle de valve dans le boîtier
• * réaliser avec une pince à sertir le repliement de la jupe externe de la coupelle sous le rebord du col provoquant ainsi un serrage de la coupelle et du joint d'étanchéité.

This process consists of:

• * choose a valve cup whose part entering the neck has an external diameter substantially equal to the internal diameter of the neck, the external diameter of the valve cup, however, being slightly less than the internal diameter of the neck, typically 0.2 mm , to facilitate the introduction
• * place an annular seal on the rim of the neck
• * insert the valve cup into the housing
• * perform with crimping pliers the folding of the outer skirt of the cup under the rim of the neck, thus causing the cup and the seal to be tightened.

Using this known method, the Applicant has effectively obtained large metal dispenser boxes with a crimped valve cup. However, surprisingly, the tests carried out on the samples thus obtained showed that the level of tightness usually found on medium-sized metal dispenser boxes with crimped valve cups was not reached. These same tests have shown that the samples obtained from large metal dispenser boxes with crimped valve cup did not exhibit greater leaktightness than the same size dispenser boxes with expanded valve cup.

The problem was therefore to improve the seal for large metal dispenser boxes with a valve cup crimped externally.

To solve this problem, the applicant sought to modify the valve case-cup assembly.

OBJECT OF THE INVENTION

The present invention firstly relates to a metal dispenser box, the neck of which has a diameter greater than 22 mm, characterized in that the dispensing valve cup is crimped onto the box and that there is between the inside of the neck and the part of the valve cup which penetrates into this neck a clearance greater than 1 mm in diameter. The second object of the invention is also a method of manufacturing this dispenser housing.

STATEMENT OF THE INVENTION

In a first series of tests, the applicant attempted to modify the profile of the rim of the neck of the housing on which the outer skirt of the valve cup is folded up during external crimping. We expected a more efficient crimping therefore a better seal. These modifications have in fact proven to be ineffective.

In a second series of tests, the applicant was led in a fortuitous manner to try to crimp valve cups on a casing whose inside diameter of the neck was significantly greater than that of the outside diameter of the part of the cup returning in the neck, thus leaving a relatively large clearance between neck and cup. Despite the presence of this play, which is a priori detrimental to sealing, the distributor boxes thus obtained surprisingly gave improved results to the sealing test.

An hypothesis was developed a posteriori to try to explain such a surprising result. It is as follows: during the crimping operation, the cup is maintained on the rim of the neck with a vertical force from top to bottom. This force and the crimp itself cause the seal to flatten. When there is no play between the cup and the neck, the seal has no space to deform. In the event that a clearance separates cup and neck, the joint can deform more easily and be more effective.

Following this good result, the Applicant has carried out numerous additional tests to confirm it. It thus determined that the most advantageous range was a play with a diameter of between 1 and 3 mm. Beyond 3 mm, the sealing results remain satisfactory but begin to deteriorate. It also found that the invention was particularly advantageous for dispenser boxes whose neck diameter is between 25 and 28 mm.

FIGURES

• Figures 1, 2 and 3 of Plate 1 represent the successive steps of an external crimping of the valve cup, conventional for plastic dispensing boxes or medium-sized metal dispensing boxes.
  Figure 1 shows the housing alone.
  Figure 2 shows the housing-valve assembly before crimping
  Figure 3 shows the housing-valve assembly after crimping.
• Figures 4, 5 and 6 of Plate 2 show the successive stages of conventional expansion for large metal dispenser boxes.
  Figure 4 shows the housing alone.
  FIG. 5 represents the housing-valve assembly before expansion.
  Figure 6 shows the housing-valve assembly after expansion.
• Figures 7, 8 and 9 of plate 3 show the successive steps of crimping a valve cup according to the invention for large metal dispenser boxes.
  Figure 7 shows the housing alone.
  Figure 8 shows the housing-valve assembly before crimping.
  FIG. 9 represents the housing-valve assembly according to the invention.

EXAMPLES

• on conditionne les boîtiers avec 20 grammes environ de gaz butane
• on pèse les boîtiers ainsi conditionnés après les avoir stockés 12 h à température ambiante
• on stocke les boîtiers pendant 30 jours dans une étuve ventilée à une température de 50°
• on sort les boîtiers de l'étuve et on les stocke 24 heures à température ambiante
• on repèse tous les boîtiers et on mesure la différence de poids par rapport à la première pesée
• on exprime la perte en milligrammes par jour de stockage à 50°.

For all of the tests carried out, the distributor boxes were subjected to the following tightness test:

• the boxes are conditioned with approximately 20 grams of butane gas
• the boxes thus conditioned are weighed after having stored them for 12 h at room temperature
• the boxes are stored for 30 days in a ventilated oven at a temperature of 50 °
• the boxes are removed from the oven and stored for 24 hours at room temperature
• we re-weigh all the boxes and measure the difference in weight compared to the first weighing
• the loss is expressed in milligrams per day of storage at 50 °.

Example 1 (reference)

The valve cups were expanded on 20 conventional aluminum boxes with an inside diameter of the neck of 25.4 mm. The valve cups were of the "swelling" type. The 20 distributor boxes thus obtained were subjected to the tightness test. The average leak rate for the 20 dispenser boxes was 30 mg / day.

Example 2 (conventional external crimping)

Valve crimps were externally crimped onto 20 conventional aluminum enclosures with an inner neck diameter of 25.4 mm. The outside diameter of the cup portion entering the neck was 25.2 mm. The average leak rate measured for the 20 dispenser boxes was 32 mg / day.

Example 3 (external crimping according to the invention)

Valve crimps were externally crimped onto 20 aluminum enclosures with an internal diameter of the neck of 26.9 mm. The outside diameter of the part of the cups to be introduced into the neck was 25.2 mm, identical to that of the cups of Example No. 2. The average leakage rate measured for the 20 dispenser boxes was 10 mg / day only.

Claims (5)

Metal dispenser box comprising a metal box having a neck with an internal diameter greater than 22 mm and a valve fixing cup which fits into said neck and overlapping it, characterized in that said cup is crimped onto said box by external crimping and that there is between the inside of said neck and the part of said cup which penetrates into said neck, a clearance greater than 1 mm in diameter. Dispenser box according to claim 1 characterized in that the diameter of said neck is between 25 and 28 mm. Dispenser box according to any one of claims 1 and 2 characterized in that the clearance between the inside of said neck and the part of said cup which penetrates into said neck is between 1 and 3 mm in diameter. Method of manufacturing a metal dispenser box comprising a metal box having a neck with an internal diameter greater than 22 mm and a valve fixing cup returning to said neck and overlapping it, characterized in that: a) said metal case is produced with a neck with an inside diameter greater than at least 1 mm than the outside diameter of the part of said cup returning to said neck; b) an annular seal is deposited on the edge of said neck; c) introducing said cup into said neck d) the crimping of said cup is carried out by causing with a pliers the folding of its outer skirt below the rim of said neck. A method according to claim 4, characterized in that said neck has an inside diameter greater than 1 to 3 mm than the outside diameter of the part of said cup entering said neck.

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