EP0995697B1 - Spherical plastic aerosol - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aerosol dispenser which possesses a container for holding a product, bears internal vacuum, and suppresses manufacturing cost. <P>SOLUTION: While possessing the container of a ball shape, the container has an opening to which a distribution valve is attached, and the container manufactures the aerosol dispenser made from thermoplastics of higher temperatures than about 80°C in the transition temperature of glass. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

The invention relates to an aerosol dispenser according to the preamble of claim 1, comprising a reservoir intended for contain a liquid product to be dispensed using a propellant, the tank being equipped with a dispensing valve, actuatable by the user for ejection a dose of product. Generally, such a distributor is also equipped, means for actuating the valve, for example a push button, connected to the valve and provided with a dispensing orifice, such as a spray nozzle.

Usually, the reservoir of such a distributor is of generally cylindrical shape, and its wall is made, in a conventional manner, of tinplate or aluminum mono-block. In general, such a tank is provided with a neck on which is fixed a valve holder cup.

Metal tanks have the advantage of having good resistance at the pressure inside the tank, especially when the temperature ambient is excessively high, for example in direct sunlight.

However, metal tanks have the disadvantage that the product there content often exerts a corrosive action on its internal wall. For these reasons, it is necessary to apply an inert protective layer on the wall internal, for example a layer of varnish or a film of material thermoplastic. Furthermore, in the case of tinplate tanks or tanks aluminum, their manufacture requires the installation of a tool of expensive production, their price being economically reasonable only because of the large number of units produced. In addition, currently only cylindrical shapes or shapes with minor variations from to the cylindrical shape are industrially feasible.

It has already been proposed to replace metal tanks with metal tanks. plastic. Thus, the document FR-A-2 567 851 describes a plastic tank, intended to receive a load under pressure. This plastic tank is in two parts, a first part forming the cylindrical side wall, and a second part formed by an attached bottom, connected to the cylindrical wall. This assembly has the disadvantage that the connection area, to be waterproof, requires very precise adjustment of the two parts to be assembled, this which is difficult to achieve by current molding techniques employed. In addition, such an assembly area always constitutes a place fragile, which is all the more annoying as the tank must resist pressures high internal.

We also know a cylindrical tank for a distributor aerosol produced by blowing a preform of thermoplastic material. Such tank made of thermoplastic material is described, for example, in the document FR-A-2 724 588. This document offers a wide variety of materials thermoplastics, in particular polyethylene terephthalate or polyethylene naphthalate.

The use of tanks made of thermoplastic material certainly has many advantages over metal tanks of the kind mentioned above. However, two major problems arise for their industrial application. In fact, the first problem, of a technical nature, consists in ensuring sufficient strength, without showing deformations or cracks, in particular at high temperatures, for example of the order of 70 ° C. or 80 ° C. Temperatures of this order of magnitude can be encountered, for example, in a car parked in direct sunlight. However, it turns out that most thermoplastic materials, when exposed to such temperatures, show a significant softening, which makes them unusable for the manufacture of tanks which must withstand, in practice, internal pressures of the '' order of 1,8 · 10 ⁵ to 10 · 10 ⁵ Pa.

European patent application EP 873 946 describes an aerosol container in the form substantially cylindrical, the body of which is made of a compound having a glass transition temperature between 74 ° C and 100 ° C.

In addition, in the aerosol field, it is common to create a partial vacuum in the tank, before the introduction of the propellant. This this way, without be bothered by the presence of air, a greater amount of propellant can be used for spraying. However, the application of such partial vacuum requires special resistance of the tank. Failing such resistance, the container may deform or even retract in response to such partial vacuum. For this purpose, starting from a cylindrical tank, it is possible to increase the thickness of the tank wall, to give it more high resistance to internal underpressure. However, this solution is to proscribe because the second problem posed by thermoplastic materials is economic. Indeed, the price of certain thermoplastic materials likely to withstand relatively high temperatures is so high that an industrial exploitation of tanks with thick walls in such a material is not possible, except to increase the price considerably of sale.

It is in particular one of the objects of the invention to provide a distributor aerosol, in particular an aerosol dispenser, the plastic reservoir of which resists suitably for an internal partial vacuum. Such an internal vacuum makes it possible to fill the tank of liquefied propellant, without being obstructed by the presence of air.

It is therefore another object of the present invention to provide a distributor aerosol, of the plastic tank type, the cost price of which is also low as possible. Yet another object of the present invention is to provide a aerosol dispenser with a plastic container that withstands strong internal pressures, especially at high temperatures. Another object still of the present invention is to minimize the amount of material plastic necessary for the manufacture of such a tank.

Other objects of the invention will appear in detail on reading the description which follows.

Also, the invention relates to an aerosol dispenser for dispensing a produced using a propellant gas, comprising a reservoir having substantially the shape of a sphere, this reservoir being provided with an opening on which is mounted a distribution valve, said reservoir being formed of a material thermoplastic with a glass transition temperature above 80 ° C.

By the term "reservoir having substantially the shape of a sphere" is meant a reservoir, the body of which has substantially no portion, and in particular no middle portion, having a cylindrical, frustoconical or concave.

Preferably, a material is chosen whose glass transition temperature is greater than about 105 ° C, and more particularly equal to or greater than about 115 ° C.

Advantageously, the opening of the reservoir is delimited by the free edge of a neck, said neck comprising a crimping bead for fixing a cup supporting said dispensing valve. It is possible, however, to use a tank without neck. In this case, in the opening can be fixed a valve whose body is made of elastomer. Such a valve to be mounted on a container without a neck is described, for example, in documents FR-A-2,741,933 and FR-A-2,757,488.

According to a preferred embodiment, the reservoir has, substantially opposite to the opening, a bottom, capable of allowing the stable placement of said dispenser on a substantially flat surface. To this end, advantageously, the bottom is formed by an annular bead.

According to an interesting aspect of the invention, the distributor tank is formed a wall (excluding neck and bottom) whose thickness is between 0.15 mm and 0.5 mm. This thickness is sufficient to be able to condition a product to the interior of the tank and a propellant gas, in particular a propellant gas liquefiable, and in particular a propellant gas such as isobutane, butane, pentane or isopentane or a mixture thereof. With such a thickness, we minimize consumption of raw material during the manufacture of the tank.

According to a preferred embodiment, the reservoir has a volume of between 50 cm ³ and 280 cm ³ . Preferably, the reservoir is transparent or translucent. This allows you to view the degree of filling of product in the tank.

To make the tank, advantageously a blow-stretch process is used a parison of appropriate shape. Such a process is well known by the skilled person. Thus, a blow-stretch process is described, by example, in document FR-A-2 386 407.

The aerosol dispenser which has just been described can be used, in particular, for the packaging and distribution of cosmetic products in spray form or of foam.

To better understand the object of the invention, we will now describe it at purely illustrative and in no way limitative, an embodiment of the invention shown in the accompanying drawing.

• la figure unique représente une vue en coupe axiale d'un distributeur aérosol conforme à l'invention, montré en position fermée.

On this drawing :

• the single figure shows a view in axial section of an aerosol dispenser according to the invention, shown in the closed position.

Also, in this figure, there is shown a distributor designated in its together by the reference 1. We see on the drawing, a tank 2 of form substantially spherical with longitudinal axis X, carrying an open neck 4 of shape cylindrical. It is understood that the sphere may have a slightly flattened or stretched along the X axis, which can be interesting for reasons aesthetics.

The reservoir contains a liquid product P, for example a hair conditioner, and a liquefiable gas such as a propane / butane mixture. The opening formed at free end of the neck 4 has a bead 6 on which is fixed, by crimping, a valve holder cup 8. Generally, the valve holder cup 8 is made of metal. To seal the mounting of the cup on the tank, an annular seal 10 made of elastomeric material is interposed between the bead 6 and the cup 8. In the center of the cup 8 is mounted, so conventional, the body 16 of a dispensing valve. The lower end of this valve is connected to a dip tube 18, extending substantially to the bottom 22 tank 2.

On the valve 16 is mounted a push button 24, provided for actuating the valve and provided with a spray nozzle 26 for dispensing the product under spray form of fine droplets.

The push button is protected by a removable protective cover 12, the lateral cylindrical wall 13 has a latching bead 14, allowing the snap-fitting of the cover on the peripheral edge of the valve holder cup 8.

On the side opposite the neck 4, the reservoir 2 forms a base provided with a bead annular 20 in excess thickness, allowing stable positioning of the dispenser 1 on a work surface. The center of the bead 20 is closed by the bottom 22, which bottom has a curved shape towards the inside of the tank.

The tank 2 is transparent, allowing to visualize the degree of filling of the tank. In accordance with a preferred embodiment of the invention, the reservoir 2, including the neck 4 and the base 20, consists of a copolymer thermoplastic, formed from polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), the molar ratio of the PET / PEN units in said copolymer being 10/90. This copolymer has a temperature of glass transition of 115 ° C.

The tank 2 is obtained by stretch-blowing according to well techniques known to those skilled in the art.

Example of realization

By a stretch-blow-molding process of a PET / PEN blank (10:90), of suitable shape, the applicant has produced a substantially spherical reservoir having a volume of 214 ml. This tank is transparent and has a weight of 19 g. The wall has an average thickness of around 0.45 mm. After mounting the dispensing valve, an amount of about 100 ml to 135 ml of a liquid capillary conditioner is introduced into the reservoir. By applying a partial vacuum of - 0.6 · 10 ⁵ Pa, the air is removed to the tank. Then we crimp the valve on the tank. To pressurize the reservoir, depending on the nature of the product to be dispensed, about 15 g to about 50 g of liquefied propellant are then injected through the valve stem. At 20 ° C, the internal pressure of the reservoir reaches 1.8 · 10 ⁵ Pa. During the application of the partial vacuum, no deformation of the reservoir was observed. Likewise, by progressive heating, no significant deformation of the tank was observed up to a temperature of 75 ° C.

As a comparative test, the applicant has produced a cylindrical reservoir of 55 mm diameter and having the same volume as the spherical tank supra. To be able to withstand the pressures indicated above, it was necessary to make walls with a thickness of 0.55 mm. For the realization of such a cylindrical tank, 26 g of thermoplastic material are used.

It is thus shown that the invention allows a gain of about 25% to 30% in raw material, compared to a cylindrical container.

In the foregoing detailed description, reference has been made to modes of particular realization of the invention. It is obvious that there are variations be made without departing from the invention as claimed below.

Claims (8)

1. Aerosol dispenser (1) for dispensing a product (P) using a propellent gas, comprising a reservoir (2) having an opening on which a dispensing valve (16) is mounted, the said reservoir being made of a thermoplastic whose glass transition temperature is above 80°C, the reservoir having, opposite the opening, a bottom (22), capable of allowing the said dispenser to be placed in a stable manner on an approximately flat surface, characterized in that the reservoir, between the said opening and the said bottom, is roughly in the shape of a sphere.
2. Aerosol dispenser according to Claim 1, characterized in that the glass transition temperature of the said thermoplastic is above 105°C, and preferably at least equal to or above 115°C.
3. Aerosol dispenser according to Claim 1 or 2, characterized in that the said thermoplastic contains a copolymer of polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), the PET/PEN molar ratio in the said copolymer being about 10/90.
4. Aerosol dispenser according to any one of Claims 1 to 3, characterized in that the said opening is delimited by the free edge of a neck (4), the said neck having a crimping bead (6) for securing a dish supporting the said dispensing valve.
5. Aerosol dispenser according to any one of the preceding claims, characterized in that the bottom is formed of an annular bead (20).
6. Aerosol dispenser according to any one of the preceding claims, characterized in that the reservoir is obtained by blow-moulding/stretch-forming a parison.
7. Aerosol dispenser according to any one of the preceding claims, characterized in that the reservoir (excluding the neck and excluding the bottom) is made of a wall the thickness of which is between 0.15 mm and 0.5 mm.
8. Aerosol dispenser according to any one of the preceding claims, characterized in that it has a volume of between 50 cm³ and 280 cm³.

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