WO2010085979A1 - Container for storing and metering delivery of a bulk material - Google Patents

Abstract

The invention relates to a dispensing container (10) for a bulk material stored under pressure in a filling space (22) of the container comprises an elastically stretchable pressure body (20) bounding the filling space for generating a pressure acting on the bulk material and usable for discharging the bulk material. According to the invention, the pressure body comprises a material layer made of silicone rubber, produced from an addition cross-linked, preferably two-component silicone rubber (liquid or solid silicone).

Description

 Container for storage and metered delivery of a product

The invention relates to a container for storage and metered delivery of a product, which is received in a pressure chamber of the container.

The container considered in the context of the invention is intended to serve for the controlled dispensing, in particular, of liquid, creamy, pasty or gelatinous substances. Periodically, the container will be provided with suitable valve means which can be selectively opened by the user, for example by pressing or otherwise actuating a valve actuator (e.g., knob, lever). In the container, the substance (contents) received therein is under pressure. This pressure causes when opening the valve, that parts of the product flow out of the container. An additional force effect from the outside is not required. Depending on the design of the valve means, the outflowing substance can maintain its state of aggregation as within the container or, for example, foam on leaving the container or spread out to form a spray mist.

As pressure generating means for generating the pressure acting on the filling pressure pressure gases (propellant gas) are known, which of course usually require a pressure-resistant design of the container and at least in former times often had harmful effect on the climate. As an alternative, the use of an elastically stretchable, tubular or condom-like filling bubble has been proposed in the printed prior art, in which the filling material is filled and which expands massively during filling. The stretching work is stored in the form of potential energy in the filling bubble. This energy is used to generate the force required to dispense the product. Because the application force is applied by the (expanded) bubble itself, it can also be called a (fillable) force or pressure body. 0

Examples of containers with elastically stretchable filling bubbles whose expansion stress is used to generate the required application force can be found in DE 43 33 627 C2, DE 201 20 143 Ul and DE 201 20 142 Ul. The invention relates to containers of the type shown in these documents, ie containers (same which shape), which have an elastically stretchable and at least one filling space for the filling material limiting pressure body to produce a force acting on the Füiigut pressure.

In a container of this type, it is an object of the invention to enable mass production on an industrial scale and over a wide Füllgradbereich away to achieve acceptable application forces for the contents, which should also not change significantly over the intended storage period of the contents.

To achieve this object, the invention provides that the pressure body has at least one silicone rubber material layer, which is made of an addition-crosslinking, preferably two-component silicone rubber. Of course, one-component systems should not in principle be excluded within the scope of the invention.

It has been found that the addition-crosslinking silicone rubbers considered here, which, depending on the viscosity, can occur both as liquid silicone rubbers (LSR) and as solid silicones, can provide a force-elongation characteristic already after crosslinking (vulcanization) at very low elongation (low filling) can produce the intended or desired Ausbringkraft and then show over a comparatively large Füllbandbreite no excessive increase in the Ausbringkraft generated by them. This is advantageous for two reasons: firstly, the user of a serving as a dispenser container regularly wishes that the contents flow with as constant a speed as possible from the container, no matter how large the current degree of filling. Second, it is desirable from the user's point of view to get as much of the contents out of the container as possible. In embodiments of the container with a rigid outer housing, where a possible filling residue can not be herausbekommen by manual compression of the container, therefore, the pressure body should still be able to muster a sufficient pressure on the remaining remainder of the contents even at almost complete emptying. This requirement profile means that in the unfilled state of the container the smallest possible void volume should be present in the interior of the pressure hull (this defines not, at least ausbringbaren by self-contraction of the pressure hull Füllgutrest) that at the same time but the pressure hull comparatively 5 be highly stretchable should be able to provide an acceptably large fill volume. It has been found that acceptable discharge levels can be achieved with a pressure bladder made from addition-crosslinking silicone rubber for practical use. The pressure body is expediently dimensioned and designed such that when a container according to the invention is filled with a nominal filling quantity specified for the container, the expansion energy stored in the pressure body ensures a dispensing rate of at least 87%, preferably at least 90% and more preferably at least 93% of the nominal filling quantity. at least within a planned or predetermined life or maximum storage duration of the filled container. Under certain circumstances, the invention can even ensure discharge rates of more than 95% up to more than 98%, ie 95% or 98% of the filled product quantity can be dispensed. Containers according to the invention preferably have a nominal filling volume of at least several tens of milliliters, for example at least 50 ml or at least 80 ml, and are readily usable up to nominal filling volumes of several liters. For example, containers according to the invention with nominal filling volumes in the high single-digit or even the double-digit liter range are conceivable.

In addition, addition-vulcanizing silicone rubbers permit short cycle times in the production of molded parts, in particular shorter regularly than peroxide-curing one-component solid silicone rubbers. This makes them particularly suitable for mass production. In addition, there is no supply problem of raw materials, as would be feared for example in natural rubber in the case of a large-scale industrial production. o The addition-crosslinking silicone rubbers considered in the context of the invention generally include polymers, fillers, crosslinkers and optionally further additives. The base polymer in the silicone rubber is a polyorganosiloxane. This consists of a skeleton of silicon atoms, which are linked via oxygen atoms (-Si-O-Si-O-), wherein the free valences of the silicon atoms are saturated by or ganische groups such as hydrogen, methyl or vinyl. The unvulcanized or uncrosslinked silicone mixture is more or less viscous and plastic. In order to obtain a rubber-elastic, solid material, therefore, the viscous, rubber-elastic silicone mixture must be vulcanized, ie crosslinked. The crosslinking or vulcanization reaction is carried out by addition of an Si-H group of crosslinker molecules to a vinyl group of a polysiloxane via a catalyzed hydrosilylation. The catalyst used in the context of the present invention is preferably a noble metal catalyst, in particular a platinum catalyst. In contrast to a peroxidic or condensation-crosslinking reaction, the platinum-catalyzed addition crosslinking has the advantage that it is much faster and does not produce any unwanted cleavage and byproducts.

In the case of two-component systems which are first mixed during processing, the first component ("A component") typically comprises the catalyst and low viscosity vinyl functional polysiloxanes, typically vinyl functional polydiorganosiloxanes. "The second component (" B component ") comprises hydrogen carbons - tional polysiloxanes and / or silane compounds as crosslinkers, preferably methylhydrogensiloxane.

The crosslinking or vulcanization reaction can be controlled by the concentration of the catalyst and an optionally present in the reaction mixture inhibitor, which is typically a component of the B component. As an inhibitor, for example, a higher alcohol, such as n-butanol, n-pentanol or n-hexanol, are used. Also, 1-ethynyl-1-cyclohexanol is a suitable inhibitor.

The silicone used in the present invention may be, for example, an MVQ liquid silicone, and preferably a platinum catalyzed, addition-crosslinked, two-part liquid MVQ liquid silicone. In such a liquid silicone, the base polymer is a methylvinyl-polysiloxane in which the silicon atoms of the Si-O backbone are linked to methyl groups and vinyl groups, with the number of methyl groups generally being significantly greater than the number of vinyl groups. By varying the vinyl group density, the crosslink density of the resulting vulcanizate can be controlled. In the context of the present invention, for example, fumed silicas, in particular fumed silicas having BET surface areas of greater than 100 m ² / g, or precipitated silicas, quartz flour or diatomaceous earths or special carbon blacks can be used as fillers. Also, chalk, mica, kaolin, Al (OH) ₃ and / or metal oxides are suitable fillers. The fillers serve to strengthen the resulting vulcanizates.

Suitable additives include, for example, dyes, pigments, anti-stick agents, plasticizers and adhesion promoters.

The crosslinked or vulcanized silicones used in the present invention for the silicone rubber sheet preferably have a density (measured according to ASTM D792) between 1.05 and 1.35 g / cm ³ , more preferably between 1.08 and 1.25 g / cm ^3, and more preferably between 1.1 and 1.2 g / cm ³ . The hardness (measured after

ASTM D2240) of the crosslinked or vulcanized silicones is preferably in the range between 38 and 82 Shore A, better in the range between 44 and 70 Shore A and even better in the range between 50 and 60 Shore A. The tensile strength (measured according to ASTM D412 C) is preferably in the range between 5.0 and 14.5 MPa, more preferably between 8.0 and 12.5 MPa. The elongation at break of the silicone rubber, measured according to ASTM D412 C, is preferably at least 80%. In certain cases, the elongation at break of the silicones used may be considerably more than 80%, for example at least 200% or at least 300% or at least 400% or at least 500%, in some cases even at least 800%.

A particularly suitable silicone in the context of the present invention is the liquid silicone rubber available from Dow Corning under the product name SILASTIC® LC-70-2004. Other silicone rubbers which can be used by way of example are marketed by Wacker Chemie AG under the product name ELASTOSIL® LR, for example the liquid silicones of the 3003 and 3005 series.

The pressure body can be produced for example by means of injection molding of the above-described addition-crosslinking silicones. For this purpose, in the case of two-component systems, the pumpable components, ie part A and part B, over suitable pump systems supplied to a mixing block and usually mixed together in a ratio of 1: 1. To change the color or achieve a certain property profile of the product, colors and additives, typically in an amount of 0.1 to 5 wt .-% can be mixed. The material is then usually fed via a static mixer of the injection unit of an injection molding machine. In order to prevent premature vulcanization, the temperature is maintained in a temperature range of about 20 ⁰ C to 30 ⁰ C. The material is then injected into a hot mold or into a hot injection mold and thereby crosslinked or vulcanized. Preferably for this purpose equipped with a cold runner system injection molds are used. These enable optimum cycle times and waste-minimized production. The resulting product is then discharged from the mold, for example by blowing off.

For use in certain areas, for example in the medical-technical, in the food-related and in the pharmaceutical sector, the manufactured pressure hulls have to fulfill certain guidelines, eg according to the FDA, which may require a night-time slowdown. This volatile, non-crosslinked components are removed from the vulcanizate. A typical tempering takes place for example at 200 ⁰ C for 4 hours in a furnace with fresh air supply.

The crosslinking or curing takes place for example at temperatures of 140 ⁰ C to 230 ⁰ C, particularly at 170 ⁰ C to 210 ⁰ C. The crosslinking or curing time depends particularly on the mold temperature and the geometry of the silicon article, especially by the Wall thickness, from. With a wall thickness of 2 mm and a temperature of 200 ^° C., the curing or vulcanization time is typically in the range of 7 to 14 seconds.

The injection pressure depends on the geometry of the runner and is usually between 100 and 1000 bar. The filling time is usually 0.5 to 5 seconds. The hold pressure is typically for 0.5 to 4 seconds at a pressure of 50 to 200 bar in order to avoid pushing back of the silicone from the cavity of the injection mold. The silicones described above have good resistance to weathering, UV and aging, high heat stability and high elasticity, advantageous fire behavior due to non-toxic combustion, and excellent physiological compatibility and environmental compatibility. They are also characterized by a high elasticity, a high pressure absorption capacity and good long-term stability (relaxation).

The pressure body may be a monolayer or a multilayer structure. In this case, it can have a single silicone rubber material layer produced from addition-crosslinking silicone rubber. Alternatively, however, it may also have a plurality of superimposed material layers, of which at least two silicone rubber material layers produced from addition-crosslinking silicone rubber are. These multiple silicone rubber material layers may at least partially lie directly on one another or be separated from one another by one or more layers of other material. In the case of a multi-layer structure of the pressure hull, all layers can be bonded together in a material-tight manner, either by direct cross-linking or by using an adhesive. However, at least some of the layers may lie on top of each other even without intimate adhesion and adhere to one another, for example, due to friction. In particular, it should not be ruled out, the double-layered (or in general: multi-layer) to carry out the pressure body on the type of packaging shown in DE 43 33 627 C2 and to manufacture only a portion of the layers of the pressure hull of an addition-vulcanizing silicone rubber, the other part of a different elastomeric material ,

In any case, preferably at least one main material layer of the pressure body is formed by a silicone rubber material layer produced from addition-crosslinking silicone rubber.

Regardless of whether provided singly or multiply, each silicone rubber material layer can be provided on the inside or / and outside with a thin coating as required, for example in the case of a particularly aggressive filling material.

In the container according to the invention, the energy for pressurizing the filling material preferably originates solely from the elastic expansion of the pressure body. The means, the container according to the invention is preferably free of any propellant gases and also free of any other mechanical force generators, by means of which the filling material located in the pressure body could be pressurized, such as a arranged outside the pressure body and acting on this spring arrangement.

The ability to make the dispensing container propellant-free, can be used to reduce the overall weight of the container by a the outer shell of the container forming, the pressure body receiving housing is made at least for the greater part of a rigid plastic material. On the other hand, previous propellant-based dispensers often require a metallic outer housing, which can bring about a correspondingly high weight. This applies, for example, to numerous fire extinguishers which can be carried in the hand or which can be strapped onto the back. A weight saving by omitting a metallic, pressure-resistant outer housing can lead to enormous ease of use in the use of the fire extinguisher.

The accompanying single drawing shows in schematic form an embodiment of a dispenser in which the invention can be used. The container - generally designated 10 - is designed here as a can or bottle-like container and has a stable, relatively rigid outer housing 12. In the exemplary case shown, the outer housing 12 is cylindrical (for example with a circular or rectangular cross-section), but in alternative embodiments it may also have a cross-section which varies over its height. The housing 12 has a housing bottom 14, an upper housing part 16 and a jacket 18 extending between the bottom 14 and the upper part 16. Because the container 10 is free of propellant gas, the housing 12 can be made less resistant compared to pressure-resistant metal housings. It may therefore consist of a comparatively lightweight material and / or be designed comparatively thin-walled. For example, the housing 12 can be made of a plastic material or even at least partially of a cardboard material. It goes without saying, however, that the invention can equally be used with a metal housing, as is known, for example, from conventional spray cans with a sheet-metal housing. Housed in the housing 12 is a rubber-elastic pressure body (filling bladder) 20 which is made in one layer and which is produced by injection molding of an addition-crosslinking liquid or solid silicone rubber. The pressure body 20 is designed here as a single-chamber bladder, which limits a single filling space 22 for the product to be stored in the dispensing container 10. In alternative embodiments, the pressure body 20 may also form, if necessary, at least two separate filling chambers. On the upper housing part 16, a dispensing unit 24 (valve assembly) is fastened with a dispensing valve, not shown, which can be selectively opened by the user for the delivery of filling material from the container 10 by means of a trained here as a depressible actuator operating element 26. The substance to be dispensed exits at a dispensing opening 28, for example in strand form, as a foam or as a spray. The pressure body 20 is connected in a manner not shown close to the dispensing unit 24. Exemplary constructions for the tight coupling of a stretchable elastomer body serving for filling material reception to a dispensing unit can be taken from the documents DE 201 20 142 U1 and DE 201 20 143 U1 mentioned above.

In the empty, ie not yet filled, state, the pressure body 20 has, for example, the shape of a tube piece or tube closed at the bottom, for example in the form of a rolled-out condom with a small void volume. In this state, the pressure body touches neither the bottom 14 of the housing 12 nor the jacket 18. The small size of the void volume of the pressure hull 20 in the unfilled state ensures a correspondingly high discharge rate (emptying rate). When filling the pressure body 20, this expands both in length and in width until it finally comes into contact with the jacket 18 and the bottom 14 of the housing 12. This situation is shown in FIG. It is understood that the state shown in Figure 1 does not yet have to be the final filling state; Another filling beyond the state of FIG. 1 addition is quite possible. In the filled state, for example, the pressure body 20 shows the shape of a bubble (comparable to an inflated balloon). The pressure necessary for filling is absorbed by the elasticity of the pressure body 20 and is stored there in the form of potential energy. When the dispensing unit 24 is actuated, the stretched pressure body 20 forces a portion of the contents contained therein out of the filling space 22; Here, the pressure body 20 pulls something together. The for the application The filling force required by the filling material is therefore applied solely by the pressure body 20

The pressure body 20 is preferably designed so that it is applied to the housing bottom 14 when filled up to a predetermined nominal filling quantity, but there is no upturning, ie. sometimes lifts off from the ground 14 and bulges toward the inside of the housing away from the ground. An abutment of the pressure hull 20 on the housing bottom 14 ensures stabilization of the pressure hull within the housing 12. This stability is jeopardized if the pressure hull kinks and thus in places removed from the ground. In addition, reduced by such a collapse of the pressure hull 20 of the available filling space.

Containers according to the invention are suitable for the metered delivery of any liquid, pasty, creamy or gelatinous substances. They can also be used for example as a fire extinguisher and serve for the application of a suitable flowable extinguishing powder or extinguishing gel.

Exemplary substances which can be applied in a controlled manner with the container according to the invention are from the field of cosmetics creams and lotions for body care, shaving gels and shaving foams, hair sprays, hair foams, deodorant sprays, foot sprays and perfumes, from the field of pharmaceutical substances asthma sprays, nasal sprays From the household sector room sprays, polishing sprays, laundry starches, carpet foams, insecticides, leather sprays, impregnating sprays, ironing sprays, bathroom cleaners, etc., from the technical field car care products and lubricants, and from the food industry spray cream, mayonnaise, ketchup, mustard and cheese. It is understood that these are only exemplary products and applications and that numerous other applications are possible.

Claims

claims 1. Container for storage and metered delivery of a filling material, wherein the container has an elastically stretchable arranged pressure body (20) for receiving the filling material and for exerting pressure on the contents received therein, characterized in that the pressure body has at least one material layer of a silicone rubber, which is made of an addition-crosslinking silicone rubber. 2. Container according to claim 1, characterized in that the silicone rubber has a hardness, measured according to ASTM D2240, in the range between 38 and 82 Shore A, preferably in the range between 44 and 70 Shore A and more preferably in the range between 50 and 60 Shore A. has. 3. Container according to one of the preceding claims, characterized in that the silicone rubber has a density, measured according to ASTM D792, between 1.05 and 1.35 g / cm ³ , preferably between 1.08 and 1.25 g / cm ³ , 4. Container according to one of the preceding claims, characterized in that the silicone rubber has a tensile strength, measured according to ASTM D412 C, in the range between 5.0 and 14.5 MPa, preferably between 8.0 and 12.5 MPa. 5. Container according to one of the preceding claims, characterized in that the elongation at break of the silicone rubber, measured according to ASTM D412 C, at least 80%. 6. Container according to one of the preceding claims, characterized in that when filling the container with a specified for the container nominal filling amount in the pressure body (20) stored strain energy at a discharge rate of at least 87%, preferably at least 90%, more preferably at least 93% of the nominal filling quantity guaranteed. 7. Container according to one of the preceding claims, characterized in that the silicone rubber is a two-component rubber. 5 8. Container according to one of the preceding claims, characterized in that the silicone rubber material layer is a Hauptmateriallage the pressure hull (20). 9. Container according to one of claims 1 to 8, characterized in that the pressure body (20) has a single made of addition-crosslinking silicone rubber herge- lo set silicone rubber material layer. 10. Container according to one of claims 1 to 8, characterized in that the pressure body has a plurality of superimposed layers of material, of which at least two silicone rubber made of addition silicone rubber are i5 rubber material layers. 11. Container according to one of the preceding claims, characterized in that the silicone rubber material layer is coated on the inside and / or outside. 0 12. Container according to one of the preceding claims, characterized in that the silicone rubber material layer is produced by injection molding. 13. Container according to one of the preceding claims, characterized in that the pressure body (20) is accommodated in a stiffer compared to thisgehäuse 5 executed. 14. Container according to claim 13, characterized in that at least one over ^¬ weighing part of the housing (12) is made of a plastic material, cardboard or sheet metal. 0 15. Container according to claim 13 or 14, characterized in that the pressure body (20) is designed so that it rests upon filling up to a predetermined nominal filling quantity without invagination on a bottom (14) of the housing (12).