WO2002062679A1

WO2002062679A1 - Method for producing spray cans comprising an inner container

Info

Publication number: WO2002062679A1
Application number: PCT/CH2002/000078
Authority: WO
Inventors: Hans F. Stoffel
Original assignee: Stoffel Hans F
Priority date: 2001-02-08
Filing date: 2002-02-08
Publication date: 2002-08-15
Also published as: WO2002062679A9

Abstract

The invention relates to a method for producing spray cans comprising an inner container (5). In the assembled state, said inner container (5) is connected to the outer container (1) by means of a valve body (6) comprising an output valve (9). The inner container (5) is used to receive the medium to be sprayed and a propellant is introduced between the inner container (5) and the inner side of the outer container (1). Before inserting the inner container (5) into the outer container (1), the connecting area between the inner container (5) and the valve body (6) is sealed by means of a hardening sealant or adhesive agent (4). Adhesion of the outer side of the inner container (5) to the inner side of the outer container (1) is thus reliably avoided during the production of the spray can, and it is ensured that the inner container (5) is emptied correctly. Advantageously, a vertical bag can be used as an inner container (5), and a liquid gas can be used as a propellant.

Description

METHOD FOR PRODUCING SPRAY CAN WITH INTERNAL CONTAINER

The present invention relates to a method for

Manufacture of spray cans with inner container after

The preamble of claim 1, an inner container according to the

The preamble of claim 9 and a spray can according to claim 10.

Such spray cans generally have a relatively rigid outer container and a flexible inner container located therein, often in the form of a laminate bag. The inner container is filled with the spray medium via a valve body, which fills the opening on the top of the outer container and is connected to it. releases this via the valve body as required.

A method for producing such a spray can is known for example from WO 90/10583. A dispensing valve is attached to a flexible inner container, which is integrated in a valve body. The valve body with the inner container attached to it is inserted into the outer container of the spray can and is gas-tightly connected to it by crimping the edges of both the outer container opening and the valve body. The inner container is then filled with liquid or pasty spray medium and the interior between the outer container and inner container filled with propellant gas.

The big problem with this method is that the propellant gas can escape to the outside at the connection between the inner container and the dispensing valve, in particular if compressed air under high pressure is used as the propellant gas. In order to counter this, it is known to provide this area with a sealing compound, conventionally often with a low-viscosity synthetic resin. In this case, the outer container is first filled with the liquid synthetic resin in a predetermined amount via its opening, then the inner container with the valve body is inserted, which is then connected to the outer container. This is conventionally done in the standing position of the outer container, ie with the opening of the outer container facing upwards. Then the sprayed material is filled into the inner container and the propellant gas into the space between the inner container and the outer container and the can is then turned upside down by approx. 180 °. As a result, the still liquid synthetic resin flows from the bottom of the outer container into the area of the opening of the latter, which is now closed by the valve body with the inner container attached to it. The synthetic resin thus reaches the area of the connection between the inner container and the valve body and seals it. After the curing time of the synthetic resin, which can take from one to several hours, this seal is completed and the can is ready for use. A disadvantage of this procedure, however, is that there is a risk that the inner container will at least partially come into contact with the inside of the outer container before the can is turned over and will be glued to it by the synthetic resin flowing downward along the inside of the outer container. As a result, the inner bag cannot be completely emptied and part of the spray medium cannot be used. If so-called stand-up pouches or bottom-up pouches are to be used as inner containers, there is also the risk that the bottom area of these inner containers will completely nestle against the inside of the outer container after being filled with the spraying agent and thus practically completely or at least drain the synthetic resin after twisting the can prevented to a significant extent. As a result, no reliable sealing of the inner container and the valve body is achieved and the problem described at the outset is not eliminated.

The object of the present invention was to find a method for producing such spray cans which eliminates the disadvantages described and also allows the use of propellant gases under high pressure.

According to the invention, this object is achieved by a method having the features of claim 1. Further preferred embodiments of the method according to the invention result from the features of claims 2 to 9. - 4 -

The object is further achieved by means of an inner container according to claim 9 and a spray can according to claim 10.

Because the inner container is sealed with the valve body by applying a sealing compound before being inserted into the outer container, it is advantageously possible to dispense with subsequent sealing from the inside by means of a low-viscosity sealant. Liquid gas can thus advantageously also be used as a blowing agent, because it can no longer influence the hardening process of the seal, since this is already complete at this point in time. A considerable saving in sealant can also be achieved.

A major advantage is also to be seen in the fact that, due to the fact that the sealing point is accessible from the outside, a fast-curing sealant or adhesive can be used, preferably based on two components. By supporting the supply of heat or by using UV-curing adhesive or Sealants can drastically reduce the curing process compared to the conventional process with thin, self-curing sealants, which means that much shorter production times for such spray cans can be achieved. Preferably, the cans preassembled in this way and advantageously already fumigated can also be stored temporarily and / or transported, for example, to another operating site until they are filled with the spraying agent in due course.

Rolled-up laminate bags are preferably used as inner containers and are fixed in this rolled state by a connecting means. The connecting means, preferably adhesive tapes with a predetermined breaking point or a comparatively low tear load, keep the laminate bag fixed in this compact state until they tear through the filling process with the spray material and thus allow the inner container to expand.

So-called stand-up pouches can preferably be used in this method without the risk that they could prevent the sealant from flowing to the inside of the valve body.

So that the sealing by the sealant or adhesive between the collar of the inner container and the valve body can take place particularly reliably, the collar in the area of the connection to the valve body preferably has a weld seam that extends over a certain distance and runs parallel to the valve axis. This distance is preferably between about 5 - 15 mm, in a particularly preferred manner this distance is 3 - 6 mm, after which the weld seam is then vertical or is formed obliquely outwards to the edge of the inner container. In particular, the capillary action. the creep effect increases, which the sealing or. Allows adhesive to flow from the valve body to the collar of the inner container, thus creating a diffusion-proof seal between the inside of the outer container and the inner container, ie between the propellant gas and the spray medium.

In addition to conventional blowing agents such as air under high pressure, liquid gas can also advantageously be used by the process according to the invention. This has the advantage that practically a constant pressure is provided from the fully filled state to proper emptying and thus a much lower initial pressure can be used compared to gas or air. Furthermore, sticking of the inner container to the inside of the outer container is completely ruled out, since there are no effective adhesives in the room at the time of inserting or unfolding the inner container.

Furthermore, such spray cans can be pre-gassed before being filled with spraying agent and then transported, for example, to another plant and / or stored temporarily. An embodiment of the present invention will now be explained in more detail below with reference to drawings. Show it

Fig.l schematically in cross section an embodiment of a valve body with a rolled inner container which according to the invention has been connected to the inner container before insertion into the outer container;

2 schematically shows the view of the area of the valve body as in FIG. 1 with the inner container in the original form before rolling in; and

3 shows the schematic cross section through a fully assembled can before filling with the spray medium.

In FIG. 1, the cross section through the upper region of an inner container 5 preassembled according to the invention with the valve body 6 attached is shown schematically - in an overhead position.

The valve body 6 acting as a valve carrier has, for example, the dispensing valve 9 in the center of its ring 7 (flanged edge). The dispensing valve 9 is preferably surrounded by a conical jacket-shaped holder of the valve body 6 and connected to it in the radial direction on the inside. On a riser pipe holder 10 - jacket of the discharge valve 9 - the collar 5 ^{1 of} the inner container 5 is attached or. pushed on and connected via the weld 11. The weld seam 11 of the inner container 5 (see also FIG. 2) runs in the region of the collar 5 ¹ a small distance parallel to the riser pipe holder 10 before it runs radially or preferably obliquely away from the riser pipe holder 10 to the edge of the inner container 5.

This configuration of the collar 5 'of the inner container 5, respectively. the connection point to the riser pipe holder 10 of the valve body 6 favors the sealing by the sealing or. Adhesive 4 at this point, without there being any risk that the inner container 5, which is preferably still rolled up, will be glued at this point.

The sealing or Adhesive 4 can preferably be introduced in the upside-down position of the inner container 5, that is to say with the valve body 6 pointing downward, into the space 12 formed by the conical configuration, the collar 5 'of the inner container 5 thereby also covering at least part of its length and a reliable seal can be achieved. Due to the capillary action between the collar 5 'of the inner container 5 and the riser holder 10, the sealing or. Adhesive 4 drawn into the contacting areas in this area, which makes the particularly reliable Sealing along this critical area is achieved.

As a sealing or Adhesive can be used a fast curing medium, such as preferably a two-component epoxy resin or a UV curing sealant. Adhesive material because the application is accessible from the outside. The curing of the sealing or Adhesive 4 can additionally be supported and in particular accelerated by the action of heat or UV light at this point. This is also favored by the easy accessibility.

Of course, conventional inner containers 5 in the form of laminate bags with a straight upper edge and a straight weld seam 11 can also be used, as is shown schematically in FIG. 2 in the view. Here, for example, the sealing or Adhesive 4 are applied from the outside to the appropriate place, which can also be achieved easily and quickly by machine due to the good accessibility.

The inner container 5 prepared in this way - as shown in FIG. 1 - can now be introduced from above through the opening 2 of the outer container 1, as shown in FIG. 3. The rim 7 (flanged edge) provided with a circumferential groove of the plate-shaped valve body 6 acting as a valve carrier is placed on the rim 3 (flanged edge) of the outer container 1 and in connected in a known manner, such as crimped, preferably after the propellant has been introduced into the interior of the outer container 1.

As an additional seal between the outer container 1 and the valve body 6, a sealing ring can be inserted between the ring 7 (flange edge of the valve body 6) and the ring 3 (flange edge of the outer container 1). Alternatively, a hot-melt adhesive, an adhesive, a two-component adhesive or the like can be applied to the surfaces of the rings 3 and 7, which reacts after the valve body 6 and the outer container 1 have been connected, for example by the action of heat and in a short time as a tight one Adhesion can harden.

The inner container 5 is preferably parallel to the spray axis, optionally rolled up around a riser pipe, and fixed in this form, for example, by means of adhesive strips 8 (FIG. 1). This prevents the inner container 5 from touching the inner wall of the outer container 1.

Because the connection area between the inner container 5 and the valve body 6 has already been sealed in advance, the inner container 5 can now be mounted on the outer container 1 without first turning the outer container 1 and waiting for one The curing time can be filled directly with the spray medium.

Alternatively, the process can also be interrupted here, and the spray can prepared in this way can be temporarily stored and / or transported in order to be filled at a later point in time and, if necessary, in another operating facility.

By filling the inner container 5 with liquid or pasty spray material, the inner container 5 is expanded, causing the adhesive strips 8 to tear. These either have a relatively low tensile strength or have predetermined breaking points dimensioned accordingly. Since there is no adhesive sealant or adhesive 4 (FIGS. 1 and 3) in the interior between the inner wall of the outer housing 1 and the inner container 5, there is absolutely no risk of the inner container 5 sticking to the inside of the outer container 1.

In addition to the use of the flat bag shown, standing bags can also advantageously be used as the inner container 5.

The method according to the invention allows savings in sealant or adhesive 4 compared to known methods. It is also conceivable to apply a preferably two-component sealant or adhesive 4 to the areas of the valve body 6 / riser pipe holder 10 and inner container 5 which are in contact with one another, at least in regions, before the connection.

At least approximately hardened sealant or adhesive 4 is to be understood to mean that the sealant or adhesive 4 is dimensionally stable in this state, has no adhesive properties on the exposed surface, does not undergo chemical reactions with propellant or possibly liquid gas, and tightness is ensured.

In practice two different forms of propellant gas are used: the liquid and the non-liquid form. Gases in liquid form have a relatively low evaporation pressure, ie the pressure where the gas changes from the liquid to the gaseous state is relatively low. If the pressure drops, LPG is evaporated until the original pressure (the evaporation pressure) is restored. This evaporation pressure is constant at the same temperature. Compressed air, nitrogen, etc., which are also used in two-chamber cans, are not liquid. The filling quantities of the propellant gases in this form are limited by the space available. When using welded inner containers (laminate bags), a valve with a standpipe holder made of weldable material, such as polyethylene (PE), must be used. However, given the relatively coarse molecular structure, PE is not gas-tight!

On the other hand, there are two-chamber systems that do not weld the inner container to the riser pipe holder, but rather clamp and / or crimp it between the valve body and valve plate. In these applications, a valve body made of a non-weldable, but gas-tight material, such as polyamide (PA), also called nylon, can be used.

When using LPG as the propellant gas, diffusion through leaks plays a subordinate role, since the pressure loss due to small leaks is compensated for by re-evaporation. However, the amount of liquid gas that has to be filled in must be determined in such a way that compensation for loss due to leakage and complete emptying of the spray medium is nevertheless guaranteed.

When using non-liquid propellant gases, such as compressed air, nitrogen, etc., leaks can lead to the complete loss of the propellant gas pressure and thus also to the function of the two-chamber can. The present Invention exactly prevents these leaks and solves the sealing task.

The advantage of the invention is that the sealing, respectively. Adhesive (4), which completely surrounds the collar (5 ¹ ) of the inner container (5) and the exposed part of the riser pipe holder (10), the entire space (12) is completely sealed, so that even when using a non-gas-tight riser pipe holder (10 ) For example, no propellant gas can escape from polyethylene (PE).

Another advantage of the invention is that the space (12) formed by the conical valve body (6) and the riser pipe holder (10) with sealing, respectively. Adhesive (4) is filled, and is therefore completely gas-tight.

Claims

claims

1. A method for producing spray cans with an inner container (5), in which the inner container (5) is connected to an outer container (1) via a valve body (6) with a discharge valve (9), and the inner container (5) for receiving a spray medium and the space between the inner container (5) and the inside of the outer container (1) is intended for receiving a propellant gas, characterized in that at least before the inner container (5) connected to the valve body (6) is introduced into the outer container (1) the connection point between the inner container (5) and the valve body (6) is sealed with a hardening sealant or adhesive (4) for sealing and this is at least approximately hardened.

2. The method according to claim 1, characterized in that the areas of the inner container (5) and the valve body (6) which abut one another in the connected state are acted upon with a sealant or adhesive (4) at least in regions before the connection.

3. The method according to claim 1 or 2, characterized in that as a sealing or. Adhesive (4) a two-component agent is used.

4. The method according to any one of claims 1 to 3, characterized in that a laminate bag is used as the inner container (5), which is rolled up around the valve axis and fixed with a holding means (8) with predetermined breaking point, preferably one or more tapes.

5. The method according to any one of claims 1 to 3, characterized in that a stand-up pouch is used as the inner container (5).

6. The method according to any one of claims 1 to 5, characterized in that the outer container (1) is temporarily stored after gassing with propellant gas and before filling the inner container (5) with spray.

7. The method according to any one of claims 1 to 6, characterized in that a laminate bag with a collar (5 ¹ ) is used as the inner container (5), in which the connecting weld seam (11) over a small distance, preferably about 3 - 6 mm, runs parallel to the valve axis and only then outwards to the edge of the laminate bag, and the collar (5 ') is acted upon with sealant or adhesive (4).

8. The method according to any one of claims 1 to 7, characterized in that as a sealing or. Adhesive (4) Epoxy resin is used, preferably a two-component epoxy resin.

9. inner container (5) with a valve body (6) with dispensing valve (9) for use in the method according to one of claims 1 to 8, wherein the valve body (6) for connection to an outer container (1) and the inner container (5) for Recording a spray medium are determined, characterized in that the connection point between the inner container (5) and the valve body (6) for the purpose of sealing with a sealant or adhesive (4) and this is at least approximately cured.

10. spray can with an inner container (5), which is connected via a valve body (6) with dispensing valve (9) to an outer container (1), and the inner container (5) for receiving a spray medium and the space between the inner container (5) and the inside of the outer container (1) are intended for receiving a propellant gas, characterized in that the connection point between the inner container (5) and the valve body (6) is acted upon with a sealing or adhesive (4) for sealing purposes and this is at least approximately hardened, and the inside of the outer container (1), possibly with the exception of the connection area with the valve body (6), is free of sealant or adhesive (4).