EP2013114B1 - Pressure vessel containing polyethylene glycols and carbon dioxide as a propellant - Google Patents

Abstract

Disclosed are pressure vessels, especially an aerosol container, which comprise an interior that is subdivided into a storage chamber (3) and a propellant chamber (4) and are operated by means of a two-phase propellant. The gas phase (5) of the propellant encompasses carbon dioxide while the liquid phase (6) encompasses polyethylene glycol and/or a (C1-C4) monoether and/or a (C1-C4) diether of a polyethylene glycol, and carbon dioxide that is dissolved therein.

Description

Field of the invention

The present invention relates to pressure vessels, in particular aerosol cans, in which the propellant and the pressurized material are present in separate chambers.

Background of the invention

The above-mentioned pressure chambers with separate chambers have the advantage over ordinary, single-chamber pressure or aerosol containers in that they are capable of dispensing the product in any spatial orientation, without first having to shake the container. Another advantage of these two-chambered containers is that no consideration has to be given to any chemical incompatibilities between the propellant and the product.

Examples of such containers are, on the one hand, the spray containers, which contain a flexible bag with the material to be sprayed inside, and wherein the blowing agent fills the gap between this bag and the actual container. With increasing emptying of the container of material to be sprayed, the bag is compressed by the action of the propellant and thus ensures that the remaining portion of the material to be sprayed is still under pressure. For such containers, the term "bag in a can" is often used in the art. Examples for the filing date The two-chamber containers of this first type available on the market in the present application are the containers marketed by the assignee of the present application under the trade names LamiPACK, COMPACK, MicroCOMPACK, and AluCOMPACK. Other examples are the containers of the Bican ^® brand from Crown Aerosols (England), the containers by the company EP Spray Systems SA (Switzerland) under the trade name "EP Spray" sold, and from the United States Can Company under the brand Sepro ^® available containers.

Another category of such containers are those known in the art by the term "can-in-a-can". Here, instead of the flexible bag, a second, inner box is provided which gradually folds up under the action of the propellant and with increasing emptying.

Another category of dual chamber containers are those in which the propellant presses from below onto a movable piston located in the container. This piston is typically first mounted near the container bottom; the propellant is located in the cavity between the container bottom and piston. The material to be sprayed is located above the piston in the remaining cavity of the container. With increasing emptying of the container from the material to be sprayed, the piston slides upward through the action of the propellant within the container and thus ensures that the remaining portion of the product to be sprayed is still under pressure. Such piston-containing pressure vessels are sold for example by the United States Can Company.

The blowing agents used in the two-chamber containers described above are typically gaseous carbon dioxide, air, nitrogen, liquid gases such as propane and butane, fluorine-chlorine hydrocarbons or fluorocarbons.

In an article (" ACS Symposium Series, 2002, pages 166-180 ), the solubility of carbon dioxide in PEG 400 has been determined with a view to providing solvents for the catalytic reduction of carbon dioxide (with respect to the reduction of greenhouse gases).

In another article (" Canadian Journal of Chemical Engineering "83 (2), 2005, pp. 358-361 ), also with a view to reducing the greenhouse gas carbon dioxide, the solubility of carbon dioxide in various ethers of various polyethylene glycols was investigated.

Object of the present invention is to provide an improved pressure vessel of the type mentioned.

Summary of the invention

1. a) einer Gasphase, die Kohlendioxid umfasst, und
2. b) einer flüssigen Phase, die eine aus den Polyethylenglykolen und ihren ihren (C₁-C₄) Monoethern und (C₁-C₄) Diethern ausgewählte Verbindung und darin gelöstes Kohlendioxid umfasst.

The object is achieved according to the invention by a pressure vessel for receiving a pressurized gaseous, liquid or finely divided material comprising a wall with a wall inside, which defines an interior of the pressure vessel; a separating part located in the inner space, which subdivides the inner space into a storage chamber and into a propellant chamber, wherein the storage chamber comprises the goods and the propellant chamber comprises a propellant, wherein the separating part is capable of liquid-tight subdivision into the storage chamber and propellant chamber and, under the action of the propellant, to vary the volume ratio between the storage chamber and the propellant chamber in favor of the propellant chamber;
the pressure vessel being characterized in that the propellant consists of:

1. a) a gas phase containing carbon dioxide, and
2. b) a liquid phase comprising a compound selected from the polyethylene glycols and their (C ₁ -C ₄ ) monoethers and (C ₁ -C ₄ ) diethers and carbon dioxide dissolved therein.

Preferred embodiments of the pressure vessel and other objects of the invention will become apparent from the claims.

Brief description of the figures

Fig. 1

shows a pressure vessel according to the invention with a movable piston in two different filling states.

Fig. 2.3

show two further inventive pressure vessel with inner bag in two different filling states.

Fig. 4,5,6

show in pressure vessels according to the invention, the dependence of the pressure in the propellant chamber on the temperature, if it is assumed that three different output pressures at 25 ° C.

Fig. 7,8

show in pressure vessels according to the invention the dependence of the pressure in the propellant chamber on the sprayed volume of the material to be sprayed.

Description of the invention

The pressure vessels according to the invention comprise a propellant with a liquid phase which comprises a polyethylene glycol and / or a (C ₁ -C ₄ ) monoether and / or a C ₁ -C ₄ ) diether of a polyethylene glycol. The polyethylene glycols or their ethers may be present as pure substances; As a rule, however, the polyethylene glycols or their ethers, as a result of their preparation, are mixtures of compounds having different, approximately normally distributed molecular weights.

verstanden, wobei i ein über alle Molekülarten des Polyethylenglykols und/oder Polyethylenglykolmonoethers und/oder Polyethylenglykoldiethers laufender Index ist, und N_i bzw. M_i die Anzahl der Moleküle in der i-ten Molekülspezies bzw. das Molekulargewicht der i-ten Molekülspezies sind. Dieses mittlere Molekulargewicht M_w kann, wie in der Technik üblich, über Lichtstreuungsmessungen nach dem Prinzip des "Multi Angle Light Scattering" (MALS) mit Laserlicht an verdünnten Lösungen des Polyethylenglykols oder Polyethylenglykolethers bestimmt werden. Die hierzu erforderlichen Messgeräte sind bekannt und im Handel erhältlich. Die Bestimmung des M_w aus den erhaltenen Streuungsmessungen kann über die Zimm-Gleichung und das zugehörige Zimm-Diagramm erfolgen.In the context of the present application, the molecular weights of mixtures of polyethylene glycols or their ethers as mass average weights M _w : $$M_w=\frac{\underset{i=1}{\overset{Z}{\Sigma }}{N}_i{M}_i{M}_i}{\underset{i=1}{\overset{Z}{\Sigma }}{N}_i{M}_i}$$

where i is an index running across all molecular types of the polyethylene glycol and / or polyethylene glycol monoether and / or polyethylene glycol diether, and N _i and M _i, respectively, are the number of molecules in the ith molecular species and the molecular weight of the ith molecular species. This average molecular weight M _w can, as is customary in the art, be diluted by means of laser light scattering measurements based on the principle of "Multi Angle Light Scattering" (MALS) Solutions of the polyethylene glycol or polyethylene glycol are determined. The required measuring devices are known and commercially available. The determination of the M _w from the obtained scattering measurements can be made using the Zimm equation and the associated Zimm diagram.

The M _{w of} the polyethylene glycol and / or the ether thereof can be selected depending on the ambient temperatures at which the pressure vessel according to the invention is to be used: At higher ambient temperatures, a higher molecular weight polyethylene glycol and / or a higher molecular weight polyethylene glycol ether can be used; wherein the polyethylene glycol should be liquid at the desired ambient temperature. The following table lists the typical melting intervals of some representative polyethylene glycols which can be used according to the invention, depending on their molecular weight: M _{w of} the polyethylene glycol Melting interval (° C) 200 -65 to -50 300 -15 to -10 400 -6 to 8 600 17 to 22

If the ambient temperature at which the pressure vessel according to the invention is to be used is in the range of about room temperature, ie from about 0 ° C. to about 40 ° C., the M _{w of} the polyethylene glycol and / or polyethylene glycol monoether and / or polyethylene glycol diether may preferably be in the range from 200 to 600 daltons, more preferably in the range of about 250 to about 390 daltons; most preferably it is about 300 daltons.

Examples of polyethylene glycol monoethers and polyethylene glycol diethers are, for example, the compounds listed in the aforementioned reference of "Canadian Journal of Chemical Engineering" in Table 1. Preferably, diethers are used.

If desired, the liquid phase of the propellant may contain a cosolvent. Such cosolvents may be antifreeze such as dipropylene glycol or ethylene glycol; it may also be viscosity modifying additives such as water; it may also be foam inhibitors such as N-octanol. These cosolvents, if they are to be present, are preferably added in amounts of from 0.1 to 5 percent by weight, based on the liquid, still carbon dioxide-free phase.

In a first preferred embodiment, the liquid phase contains only just one polyethylene glycol having M _w in the ranges indicated above, if desired in combination with one of the cosolvents mentioned above.

In another preferred embodiment of the invention, the liquid phase contains only just a polyethylene glycol diether with M _w in the ranges indicated above, if desired in combination with one of the cosolvents mentioned above. The polyethylene glycol diether is particularly preferably a polyethylene glycol 1,4-dibutyl ether, such as "Polyglycol BB 300" marketed by Clariant.

The summed content of polyethylene glycol and polyethylene glycol mono- and -diethern and dissolved therein carbon dioxide is in the liquid phase of the propellant preferably at least 90 weight percent, based on the liquid phase, more preferably at least 95 weight percent.

In the gas phase of the propellant according to the invention, the ratio of the partial pressure of the carbon dioxide to the total pressure is preferably at least 0.9, more preferably at least 0.95 and particularly preferably at least 0.98.

The blowing agent is preferably prepared before, before filling in the inventive pressure vessel. In this case, in a pressure reactor with a pressure gauge, a liquid phase comprising a selected from the polyethylene glycols and their (C ₁ -C ₄ ) monoethers their (C ₁ -C ₄ ) diethers selected compound, be subjected to carbon dioxide (if desired, the pressure reactor before Be charged with carbon dioxide evacuated to remove air debris). Preferably, with stirring or shaking, the propellant is allowed to equilibrate, which can be checked by adjusting the pressure constancy.

worin

• V_TO das Anfangsvolumen des gesamten Treibmittels, d.h. das Anfangsvolumen der Treibmittelkammer ist;
• Ng die gesamte, über die flüssige Phase und die Gasphase des Treibmittels summierte Molzahl des Kohlendioxids ist (bleibt konstant, da bei den erfindungsgemässen Druckbehältern kein Kohlendioxid abgegeben wird);
• N₁ die Summe der Molzahlen aller flüssigen Bestandteile (Polyethylenglycol, Polyethylenglycolmonoether, Polyethylenglycoldiether und Cosolventien) der flüssigen Phase des Treibmittels ist (bleibt konstant, da bei den erfindungsgemässen Druckbehältern keine flüssige Phase abgegeben wird); und
• T die absolute Temperatur ist.

For the initial pressure in the pressure vessel according to the invention, it does not matter in which ratio of liquid phase to gas phase the propellant is introduced into the propellant chamber; the initial pressure in the chamber is equal to the pressure at which the propellant is introduced into the chamber. However, the pressure drop in the propellant chamber with increasing sprayed volume ΔV is determined by the initial volume of the liquid phase and by the total propellant (ie the initial volume of the propellant chamber), the number of moles of all constituents of the propellant (these also determine the ratio liquid phase to gas phase) and dependent on the temperature: $$P=f\left(\mathrm{\Delta }V.V_{T0}.N_G.N_l.T\right)$$

wherein

• V _{TO is} the initial volume of the total propellant, ie, the initial volume of the propellant chamber;
• Ng is the total number of carbon dioxide summed over the liquid phase and the gas phase of the propellant (remains constant since no carbon dioxide is released in the pressure vessels according to the invention);
• N _{1 is} the sum of the molar numbers of all liquid constituents (polyethylene glycol, polyethylene glycol monoether, polyethylene glycol diether and cosolvents) of the liquid phase of the propellant (remains constant since no liquid phase is released in the pressure vessels according to the invention); and
• T is the absolute temperature.

The function (1a) can be determined experimentally by means of a simple measuring apparatus for each pressure vessel and propellant according to the invention (see below in the description of FIG FIGS. 7 and 8th ).

berechnen, woraus dann wiederum (1a) erhalten werden kann. Hierzu werden zunächst einige Formeln benötigt, die im Folgenden erläutert werden:

1. a) Bei den in den erfindungsgemässen Druckbehältern typischerweise vorkommenden Drücken und Temperaturen lässt sich die Gleichgewichtsverteilung des Kohlendioxides zwischen Gasphase und flüssiger Phase anhand der folgenden Formel abschätzen: $${\mathrm{<figure-callout\; id="2"\; label="P\; co"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">P</figure-callout>}}_{{\mathit{co}}_{}}=H*\mathit{xc}{\mathrm{<figure-callout\; id="2"\; label="o"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">o</figure-callout>}}_2+{\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">H</figure-callout>}}_0$$
   
   
   worin
   • P_CO2 der Partialdruck des Kohlendioxids in der Gasphase des Treibmittels ist,
   • x _CO2 der Molenbruch des Kohlendioxids in der flüssigen Phase des Treibmittels ist, und
   • H und H ₀ für die jeweilige flüssige Phase und Temperatur charakteristische Konstanten sind.
   Die Konstanten H und H₀ lassen sich nach dem Verfahren der eingangs erwähnten Publikation von "ACS Symposium Series", (Seite 168, Abschnitte "Batch Unit" und "Solubility Studies") bestimmen. In dieser Arbeit wurde für PEG mit M_w 400 bei 25°C H = 9,4 MPa gefunden (H₀ ist gemäss der dortigen Figur 3 etwa -0,5 MPa). In den zur vorliegenden Anmeldung führenden Arbeiten wurde bei 25°C für PEG mit M_w 300 für H = 32,8 MPa und für H₀ = -0,39 MPa gefunden.
2. b) Der in (2) verwendete Molenbruch x_CO2 ist definiert als: $${\mathit{xco}}_2=\frac{{{}_l\mathit{n}}_g}{{{}_l\mathit{n}}_g+N_l}$$
   
   $$=\frac{N_g-{{}_{g}n}_g}{N_g-{{}_{g}n}_g+N_l}$$
   
   
   worin
   • _ln_g die Molzahl des Kohlendioxids in der flüssigen Phase des Treibmittels ist;
   • _gn_g die Molzahl Kohlendioxid in der Gasphase des Treibmittels ist; und
   • N_g und N₁ die oben angegebene Bedeutung haben.
3. c) Wenn man (2) und (3b) kombiniert und nach _gn_g auflöst erhält man: $${{}_{g}n}_g=N_g+N_l\times \frac{P-H_0}{P-\left({\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">H</figure-callout>}}_0+H\right)}$$
   
4. d) Die Van-der-Waals-Gleichung lautet: $$\left(P+a\times \frac{{{}_g{n}_g}^2}{{}_g{V}^2}\right)\left(\frac{{}_{g}V}{{}_g{n}_g}-b\right)=\mathit{RT}$$
   
   
   worin
   • P und gng wie oben definiert sind;
   • _gV das Volumen der Gasphase ist;
   • R die universelle Gaskonstante ist; und
   • a und b die Van-der-Waals-Koeffizienten des Kohlendioxids sind; d.h. 3,96 × 10^-1 Pa m³ und 42,69 × 10^-6 m³/mol.
5. e) Das Volumen ₁ V der flüssigen Phase des Treibmittels wird approximiert als: $${}_l\mathit{V}\mathit{=}{\mathit{<figure-callout\; id="0"\; label="V\; l"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">V</figure-callout>}_l^{}}_{\mathit{0}}\mathit{+}{{}_l\mathit{n}}_{\mathit{g}}\mathit{\times }\mathit{b}$$
   
   $$\mathit{=}{\mathit{<figure-callout\; id="0"\; label="V\; l"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">V</figure-callout>}_l^{}}_{\mathit{0}}\mathit{+}\left({\mathit{N}}_{\mathit{g}}\mathit{-}{{}_{\mathit{g}}\mathit{n}}_{\mathit{g}}\right)\mathit{\times }\mathit{b}$$
   
   
   worin
   • ₁V₀ das Volumen der noch kohlendioxidfreien flüssigen Phase des Treibmittels ist (dieser Wert ist eine Konstante); und
   • N_g, _gn_g, ₁n_g und b die oben angegebene Bedeutung halben.
   
   Bei Formeln (6a) und (6b) ist angenommen, dass die flüssige Phase inkompressibel ist, d.h. dass die Volumenänderung der flüssigen Phase nur durch Aufnahme oder Abgabe von Kohlendioxid erfolgt. Des Weiteren ist angenommen, dass zwischen gelöstem Kohlendioxid und den Molekülen der flüssigen Phase keine Interaktionen stattfinden, die zu einer zusätzlichen Volumenänderung führen würden.
6. f) Das gesamte versprühte Volumen ΔV, das in (1a) und (1b) vorkommt, ist: $$\mathit{\Delta V}\mathit{=}{}_l\mathit{V}\mathit{+}{}_{g}V-V_{T\mathit{0}}$$
   
   
   worin _lV, _gV und V _T0 die oben angegebene Bedeutung haben.
7. g) Die in den Formeln (1a) , (1b) ,(3a), (3b) und (4) vorkommende Gesamtzahl der Mole N₁ in der flüssigen Phase (noch ohne Kohlendioxid, konstant) lässt sich nach der folgenden Formel (8): $$N_l=\frac{m\left(\mathit{PEG}\right)}{M_w\left(\mathit{PEG}\right)}+\frac{m\left(\mathit{PEGMonoether}\right)}{M_w\left(\mathit{PEGMonoether}\right)}+\frac{m\left(\mathit{PEGDiether}\right)}{M_w\left(\mathit{PEGDiether}\right)}+m$$
   
   berechnen, worin
   • m (PEG) , m (PEGMonoether) bzw. m (PEGDiether) die frei wählbaren Massen des Polyethylenglykols bzw. Polyethylenglykolmonoethers bzw. Polyethylenglykoldiethers sind;
   • M_w(PEG), M_w(PEGMonoether) bzw. M_w (PEGDiether) die Massen-Mittelgewichte des Polyethylenglykols, Polyethylenglykolmonoethers bzw. Polyethylenglykoldiethers sind (die sich wie vorstehend beschrieben bestimmen lassen); und
   • n₁ die Molzahl der optionalen weiteren Cosolventien sind.
8. h) Die in den Formeln (1a), (1b), (3b), (4) und (6b) vorkommende gesamte, über die flüssige Phase und die Gasphase des Treibmittels summierte Molzahl N_g des Kohlendioxids (konstant) lässt sich dabei gemäss der folgenden Formel (9): $$N_g=r\left(V_{T0}-{\mathrm{<figure-callout\; id="0"\; label="V\; l"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">V</figure-callout>}_l^{}}_0\right)+N_L\left(b\times r-1\right)\left(\frac{P_0-H_0}{P_0-\left({\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">H</figure-callout>}}_0+H\right)}\right)$$
   
   berechnen, worin
   • r die einzige reelle und positive Lösung der kubischen Gleichung $\left({\mathrm{<figure-callout\; id="0"\; label="P"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">P</figure-callout>}}_0+a\times {\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\right)\left(\frac{1}{r}-b\right)=\mathit{RT}$
     
     ist, wobei in Formel (9) und der besagten kubischen Gleichung P₀ der frei wählbare Anfangsdruck in der Treibmittelkammer ist; und
   • V_T0, ₁V₀, a, b, H und H₀ die oben angegebene Bedeutung haben.

If the gas present in the propellant is assumed to be pure carbon dioxide and the liquid constituents of the propellant are assumed to be non-volatile, the inverse function (1b) can be: $$\mathrm{\Delta }V=f^{-1}\left(P,V_{T0},N_G,N_l,T\right)$$

calculate, from which in turn (1a) can be obtained. For this purpose, first some formulas are needed, which are explained in the following:

1. a) With the pressures and temperatures typically occurring in the pressure vessels according to the invention, the equilibrium distribution of the carbon dioxide between the gas phase and the liquid phase can be estimated using the following formula: $${\mathrm{<figure-callout\; id="2"\; label="P\; co"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">P\; </figure-callout>}}_{{\mathit{co}}_{}}=H*\mathit{xc}{\mathrm{<figure-callout\; id="2"\; label="O"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">O</figure-callout>}}_2+{\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">H</figure-callout>}}_0$$
   
   
   wherein
   • P _{CO2 is} the partial pressure of the carbon dioxide in the gas phase of the propellant,
   • x _{CO2 is} the mole fraction of carbon dioxide in the liquid phase of the propellant, and
   • H and H ₀ are characteristic constants for the respective liquid phase and temperature.
   The constants H and H ₀ can be determined by the method of the aforementioned publication of "ACS Symposium Series", (page 168, sections "Batch Unit" and "Solubility Studies"). In this work, H = 9.4 MPa was found for PEG with M _w 400 at 25 ° C ( H ₀ is according to the there FIG. 3 about -0.5 MPa). In the work leading to the present application was found at 25 ° C for PEG with M _w 300 for H = 32.8 MPa and for H ₀ = -0.39 MPa.
2. b) The molar fraction x _CO used in (2) ₂ is defined as: $${\mathit{xco}}_2=\frac{{{}_l\mathit{n}}_G}{{{}_l\mathit{n}}_G+N_l}$$
   
   $$=\frac{N_G-{{}_{G}n}_G}{N_G-{{}_{G}n}_G+N_l}$$
   
   
   wherein
   • _l n _{g is} the number of moles of carbon dioxide in the liquid phase of the propellant;
   • _g n _{g is} the number of moles of carbon dioxide in the gas phase of the propellant; and
   • N _g and N _{1 have} the meaning given above.
3. c) Combining (2) and (3b) and dissolving after _g n _g gives: $${{}_{G}n}_G=N_G+N_l\times \frac{P-H_0}{P-\left({\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">H</figure-callout>}}_0+H\right)}$$
   
4. d) The van der Waals equation is: $$\left(P+a\times \frac{{{}_G{n}_G}^2}{{}_G{V}^2}\right)\left(\frac{{}_{G}V}{{}_G{n}_G}-b\right)=\mathit{RT}$$
   
   
   wherein
   • P and gng are as defined above;
   • _g V is the volume of the gas phase;
   • R is the universal gas constant; and
   • a and b are van der Waals coefficients of carbon dioxide; ie 3.96 x 10 ^-1 Pa m ³ and 42.69 x 10 ^-6 m ³ / mol.
5. e) The volume ₁ V of the liquid phase of the propellant is approximated as: $${}_l\mathit{V}\mathit{=}{\mathit{<figure-callout\; id="0"\; label="V\; l"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">V\; </figure-callout>}_l^{}}_{\mathit{0}}\mathit{+}{{}_l\mathit{n}}_{\mathit{G}}\mathit{\times }\mathit{b}$$
   
   $$\mathit{=}{\mathit{<figure-callout\; id="0"\; label="V\; l"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">V\; </figure-callout>}_l^{}}_{\mathit{0}}\mathit{+}\left({\mathit{N}}_{\mathit{G}}\mathit{-}{{}_{\mathit{G}}\mathit{n}}_{\mathit{G}}\right)\mathit{\times }\mathit{b}$$
   
   
   wherein
   • ₁ V _{0 is} the volume of the still carbon dioxide-free liquid phase of the propellant (this value is a constant); and
   • N _g , _g n _g , ₁ n _g and b are as defined above.
   
   In formulas (6a) and (6b) it is assumed that the liquid phase is incompressible, ie that the change in volume of the liquid phase takes place only by absorption or release of carbon dioxide. Furthermore, it is assumed that no interactions take place between dissolved carbon dioxide and the molecules of the liquid phase, which would lead to an additional volume change.
6. f) The total sprayed volume ΔV found in (1a) and (1b) is: $$\mathit{.DELTA.V}\mathit{=}{}_l\mathit{V}\mathit{+}{}_{G}V-V_{T\mathit{0}}$$
   
   
   wherein _l V, _g V and V _{T0 have} the meaning given above.
7. g) The total number of moles N ₁ in the liquid phase (still without carbon dioxide, constant) occurring in the formulas (1a), (1b), (3a), (3b) and (4) can be determined by the following formula (8 ): $$N_l=\frac{m\left(\mathit{PEG}\right)}{M_w\left(\mathit{PEG}\right)}+\frac{m\left(\mathit{PEGMonoether}\right)}{M_w\left(\mathit{PEGMonoether}\right)}+\frac{m\left(\mathit{PEGDiether}\right)}{M_w\left(\mathit{PEGDiether}\right)}+m$$
   
   calculate in which
   • m (PEG), m (PEG monoether) or m (PEG diether) are the freely selectable masses of the polyethylene glycol or polyethylene glycol monoether or polyethylene glycol diether ;
   • M _w (PEG), M _w (PEG monoether) or M _w ( PEG diether ) are the mass average weights of the polyethylene glycol, polyethylene glycol monoether or polyethylene glycol diether (which can be determined as described above); and
   • n _{1 is} the number of moles of optional further cosolvents.
8. h) The total in the formulas (1a), (1b), (3b), (4) and (6b) occurring, summed over the liquid phase and the gas phase of the blowing agent number of moles N _g of carbon dioxide (constant) can be according to the following formula (9): $$N_G=r\left(V_{T0}-{\mathrm{<figure-callout\; id="0"\; label="V\; l"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">V\; </figure-callout>}_l^{}}_0\right)+N_L\left(b\times r-1\right)\left(\frac{P_0-H_0}{P_0-\left({\mathrm{<figure-callout\; id="0"\; label="H"\; filenames="imgf0005.png,imgf0006.png"\; state="\{\{state\}\}">H</figure-callout>}}_0+H\right)}\right)$$
   
   calculate in which
   • r the only real and positive solution of the cubic equation $\left(P_{}\right)$$\left({}_0+a\times {\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="imgf0001.png,imgf0002.png"\; state="\{\{state\}\}">r</figure-callout>}}^2\right)\left(\frac{1}{r}-b\right)=\mathit{RT}$
     
     wherein, in formula (9) and said cubic equation P _0, the arbitrary initial pressure in the propellant chamber is; and
   • V _T0 , ₁ V ₀ , a, b, H and H _{0 have} the meaning given above.

1. a) Es wird ein Druck P gewählt, der in einem für den erfindungsgemässen Druckbehälter typischen Bereich liegt; dieser Druck sollte nicht grösser sein als der für Formel (9) gewählte Anfangsdruck P₀ ;
2. b) mit diesem P wird mittels Formel (4) _gn_g berechnet;
3. c) mit P und _gn_g wird mittels Formel (5) _gV bestimmt, indem Formel (5) zu einer kubischen Gleichung in _gV umgewandelt und _gV als die einzige reelle und positive Lösung dieser ungewandelten Gleichung bestimmt wird;
4. d) mit _g n_g wird mittels Formel (6b) ₁V bestimmt;
5. e) mit _gV und ₁V wird mittels Formel (7) das zu P gehörige ΔV bestimmt.

To determine a curve according to formula (1b), the N ₁ or N _g are previously determined by means of the formulas (8) or (9). Then, for each value pair P, ΔV of this curve to be determined, the procedure is as follows:

1. a) a pressure P is chosen which is in a range typical for the pressure vessel according to the invention; this pressure should not be greater than the initial pressure P ₀ chosen for formula (9);
2. b) with this P, _g n _{g is} calculated by means of formula (4);
3. c) with P and _g n _g , by means of formula (5) _g V is determined by transforming formula (5) into a cubic equation in _g V and determining _g V as the only real and positive solution of this unaltered equation;
4. d) with _g n _{g 1} V is determined by means of formula (6b);
5. e) _g V, and ₁ V is determined by means of formula (7) to the corresponding Δ V P.

The value pairs P, ΔV thus obtained can be plotted as P (y-axis) against ΔV (x-axis), giving a curve according to formula (1b); they can also be plotted as ΔV (y-axis) versus P (x-axis), giving a curve according to formula (1a).

The temperature dependence of the pressure in the propellant chamber of the pressure vessel according to the invention is surprisingly relatively low. This is attributed to the fact that the pressure in the gas phase, which increases with increasing temperature, is partially compensated for by the likewise increasing temperature absorption of the carbon dioxide in the liquid phase, which leads to a reduction in the amount of carbon dioxide in the gas phase. FIGS. 4 to 6 show this as an example for PEG 300 ( 4 and 5 ) and PEG dibutyl ether ( Fig. 6 ). At T ~ 25 ° C there is a pressure change of ~ 2bar. Below and above this temperature jump, the pressure is relatively constant as a function of temperature. The jump in pressure at T ~ 25 ° C takes place independently of the amount of dissolved carbon dioxide and, consequently, independent of the absolute value of the pressure at T ~ 25 ° C.

The pressure vessels according to the invention have a separating part which is capable of variably subdividing the interior of the pressure vessel into a propellant chamber and a storage chamber. As such separating member are all means that are used in prior art pressure vessels with divided interior, such as in pressure vessels of the type mentioned "bag-in-α-can", "can-in-α-can" or the type with movable piston , The materials for the separator are not critical, as far as they do not dissolve in the respective polyethylene glycol and / or mono- or diethers of polyethylene glycol. Materials for membrane-type parting agents are, for example, flexible plastics which have been rendered insoluble by crosslinking, for example vulcanized rubbers or latex, or crosslinked polyesters or polyetherpolyesters. Also suitable are laminate films or pure metal foils, such as aluminum. The separator should, because of the use of the liquid phase in the propellant, be capable of liquid-tight partitioning between the reservoir and the propellant chamber. Preferably, the separating part also forms a gas-tight barrier between the storage chamber and the propellant chamber. In the case of the pressure vessels according to the invention, the separating part is preferably designed as a movable piston or as an expandable and / or foldable inner bag.

The pressure vessel according to the invention can also have a valve and a spray head, so that the material can be released into the environment in a controlled manner by actuating the spray head and the valve. The pressure vessel according to the invention is then preferably an aerosol container or a spray can. As an alternative, it may also be a cartridge which does not yet have an outlet valve and in which only by clamping in a removal device, a hole in the container wall pricked and this is closed at the same time with a sampling valve.

The term "at least a portion of the length of the central axis" as used in the claims preferably means at least 50% by length, based on the total length of the central axis of the interior. In the case of a non-rotationally symmetrical interior, the term "center axis" is understood to mean the longest straight line which can be laid inside the interior and which is defined by the two geometric penetration points of this line through the inside of the wall of the interior; in rotationally symmetric internal spaces, the central axis is the axis of rotation. The total length of the central axis is defined in all cases by the two geometric Durchstosspunkte the central axis through the inside of the wall of the interior. The term "at least a portion of the interior" as used in the claims preferably means at least 70 percent by volume based on the total volume of the interior.

The interior has in all embodiments of the pressure vessel according to the invention preferably over at least part of the length of the central axis of the interior of rotationally symmetrical, in particular cylindrical shape.

The good that can be filled in the inventive pressure vessel is a at the temperature at which the inventive pressure vessel is used, gaseous, liquid material or a finely divided dry or suspended in a liquid Good, as in the prior art pressure vessels, in particular previously known aerosol containers, is used. As "finely divided" is in the frame understood the present application that the finely divided material can be sprayed through a conventional spray nozzle. The term "finely divided" is preferably understood as meaning a particle size which is from about 0.1 μm to about 100 μm particle diameter (measured as "mass median aerodynamic diameter" MMAD). In a particularly preferred embodiment, "finely divided" also means a particle size in an inhalable size range of about 1 to about 6 μm.

The pressure vessels according to the invention can be produced and filled in analogy to previously known pressure vessels. In particular, the embodiments for valves and spray heads, which are used for the inventive pressure vessel, analogous to the prior art pressure vessels, such as the type mentioned "bag-in-a-can" be.

As a rule, one starts from a container blank preformed from a suitable material. The blank can be made of a pressure-resistant thermoplastic, such as acrylonitrile / butadiene / styrene copolymer, polycarbonate or a polyester such as polyethylene terephthalate, or preferably a metal sheet such as stainless steel sheet or aluminum sheet. The blank preferably has the shape of a cylinder, which can be tapered in the direction of its upper cover surface with rounding. The production of this blank can be done in a conventional manner by injection molding (plastic containers) or by cold or optionally hot extrusion (in metal containers).

1. 1) Ein Druckbehälter, bei dem die Unterteilung zwischen Vorratskammer und Treibmittelkammer durch einen Kolben, eine Membran oder einen Beutel erfolgt, kann befüllt werden, indem ein Behälterrohling, der an seinem oberen Ende noch offen ist und der eine vorzugsweise nach innen gewölbte Bodenfläche mit einer verschliessbaren Öffnung aufweist, verwendet wird (dieses Verfahren ist analog zu dem in der EP-A-0 017 147 beschriebenen Verfahren). Der Kolben wird durch das noch offene obere Ende des Rohlings bis zu einer gewünschten Tiefe im Behälterrohling, die weitgehend das Volumenverhältnis zwi-, schen Vorratskammer (oberhalb des Kolbens) und Treibmittelkammer (unterhalb des Kolbens) bestimmen wird, eingeführt. Bei dieser Ausführungsform wird der Behälterrohling erst nach dem Einführen des Kolbens verjüngend verrundet, sofern dies erwünscht ist. Anschliessend wird das Gut von oben eingefüllt, so dass es auf den Kolben zu liegen kommt, und die obere Öffnung mit einem Teller, der gewünschtenfalls ein Auslassventil aufwiesen kann, unter Umbördelung mit dem Rand der Öffnung verschlossen. Als letzter Schritt wird durch die Öffnung im Boden des Rohlings das Treibmittel bis zum gewünschten Druck eingefüllt und die Öffnung mit einem geeigneten Stopfen verschlossen.
2. 2) Ein Druckbehälter, der zur Unterteilung ein Innenbeutel oder eine Membran aufweist, kann wie folgt befüllt werden: Der Innenbeutel oder die Membran wird durch die obere Öffnung eines Behälterrohlings wie bei 1) beschrieben (der aber hier oben bereits verjüngt sein kann) eingeführt und auf dem Rand der Öffnung ringsum dicht festgehalten. Anschliessend wird das Gut von oben durch die obere Öffnung eingefüllt. Dabei wird im Rohling der Innenbeutel durch die Füllung entfaltet oder die Membran gedehnt und so im oberen Teil des Rohlings eine mit dem Gut ausgefüllte Vorratskammer ausgebildet. Anschliessend wird die Öffnung mit dem auf ihrem Rand dicht aufliegenden Teil des Beutels oder der Membran mittels eines Tellers, der wahlweise ein Ventil aufweisen kann, unter Umbördelung gasdicht verschlossen. Zum Schluss wird wiederum durch die Öffnung im Boden des Rohlings das Treibmittel bis zum gewünschten Druck eingefüllt und die Öffnung mit einem geeigneten Stopfen verschlossen.
3. 3) Ein Druckbehälter mit Innenbeutel als Trennteil und mit Ventil kann auch ausgehend von einem Behälterrohling hergestellt werden, der einen Boden ohne Öffnung aufweist. Als erster Schritt wird in den Rohling von oben eine vorbestimmte Menge Treibmittel eingefüllt. Dann wird ein Teller, der ein Ventil aufweist und an dem der Innenbeutel oder die Membran bereits gasdicht befestigt ist, auf den Rand des vorgängig mit Treibmittel befüllten Rohlings aufgeflanscht oder aufgebördelt. Der Innenbeutel oder die Membran sind hier noch frei von dem zu versprühenden Gut. Vorzugsweise weist hier der Teller ein mit dem Ventil verbundenes hohles und mit Löchern versehenes Steigrohr auf, auf das der Innenbeutel oder die Membran zunächst aufgelegt oder aufgewickelt ist. Dieses Steigrohr kommt beim Anflanschen oder Anbördeln des Deckels in den Innenraum des Behälterrohlings hinein. Nach dem Anflanschen oder Anbördeln des Tellers wird das Gut durch den Ventilstem mit einem Druck, der grösser ist als der in dem Behälterrohling herrschende Innendruck des Treibmittels, in den Innenbeutel oder die Membran eingefüllt. Wenn das besagte Steigrohr verwendet wird, fliesst das Gut durch den Ventilstem in das Steigrohr und bläht über die in dem Steigrohr vorhandenen Löcher den Innenbeutel auf.
4. 4) Ein Druckbehälter mit Innenbeutel oder des Typs "can-in-α-can", mit Ventil, kann wie folgt befüllt werden: Zunächst wird der Innnenbeutel oder die Innendose, die noch unbefüllt oder schon befüllt sein können, in den Innenraum des Behälterrohlings eingebracht. Ein Ventil wird mit seinem Ventilteller allenfalls nur lose, jedenfalls aber nicht flüssigkeitsdicht, auf den Rand des Behälterrohlings aufgesetzt, oder wird in sehr geringem Abstand über dem Rand des Behälterrohlings gehalten. Über den Behälterrohling und den allenfalls lose aufsitzenden Ventilteller wird von oben her eine Füllvorrichtung nach dem Prinzip einer Glocke gestülpt, welche von aussen her fluiddicht an der Aussenwand des Behälterrohlings anliegt, was durch eine entsprechende Dichtung erreicht werden kann. Da der Ventilteller nicht dicht auf dem Rand des Behälterrohlings aufliegt, kann dann mit Hilfe der Füllvorrichtung durch den nicht fluiddichten Spalt zwischen Ventilteller und Rand des Behälterrohlings das unter Druck stehende Treibmittel in den Innenraum des Behälterrohlings eingebracht werden. Nach dem Befüllen des Innenraums mit dem Treibmittel muss der Ventilteller mit dem Rand des Behälterrohlings gasdicht verbunden werden, was typischerweise mit Hilfe einer im Ventilteller angeordneten Dichtung und wiederum durch Umbördeln des Rands des Ventiltellers erfolgt. Ist dies erfolgt, kann, wenn der Innenbeutel oder die Innendose nicht bereits mit dem zu versprühenden Gut befüllt war, das Befüllen mit dem Gut durch den Ventilstem hindurch erfolgen.
5. 5) Wenn ein Behälter mit Kolben als Trennteil verwendet wird, kann auch ein zylindrischer Behälterrohling, der oben zu ist und wahlweise bereits ein Ventil aufweist, dessen Boden aber noch offen ist, verwendet werden. Hier wird zunächst in den umgekehrten Behälterrohling eine vorbestimmte Menge des Gutes eingefüllt, dann wird der Kolben bis zu einer gewünschten Tiefe in den Rohling heruntergestossen. Dann wird eine geeignete Menge des Treibmittels eingefüllt und auf das untere Ende des Behälterrohlings unter Druck ein Behälterboden aufgeflanscht.

In the following, some exemplary filling methods are described:

1. 1) A pressure vessel in which the division between the storage chamber and the propellant chamber is made by a piston, a membrane or a bag, can be filled by a container blank, which is still open at its upper end and a preferably inwardly curved bottom surface with a closable opening is used (this method is analogous to that in the EP-A-0 017 147 described method). The piston is inserted through the still open top of the blank to a desired depth in the container blank, which will largely determine the volume ratio between the reservoir (above the piston) and the propellant chamber (below the piston). In this embodiment, the container blank is tapered only after the insertion of the piston, if desired. Subsequently, the material is filled from above, so that it comes to rest on the piston, and the upper opening with a plate, which may optionally have an outlet valve, sealed under beading with the edge of the opening. As a last step, the propellant is filled through the opening in the bottom of the blank to the desired pressure and the opening is closed with a suitable stopper.
2. 2) A pressure vessel having an inner bag or a membrane for partitioning can be filled as follows: The inner bag or membrane is inserted through the upper opening of a container blank as described in 1) (which may already be tapered up here) and on the edge of the opening around tightly held. Subsequently, the material is filled from above through the upper opening. The inner bag is unfolded in the blank through the filling or the membrane stretched and so in the upper part the blank formed a filled with the estate pantry. Subsequently, the opening with the tightly resting on its edge part of the bag or the membrane by means of a plate, which may optionally have a valve, sealed gas-tight under beading. Finally, the propellant is again filled through the opening in the bottom of the blank to the desired pressure and the opening is closed with a suitable stopper.
3. 3) A pressure vessel with inner bag as a separator and valve can also be prepared starting from a container blank having a bottom without opening. As a first step, a predetermined amount of blowing agent is introduced into the blank from above. Then, a plate having a valve and to which the inner bag or the membrane is already attached gas-tight, flanged or crimped on the edge of the previously filled with propellant blank. The inner bag or the membrane are here still free of the material to be sprayed. Preferably, the plate here has a connected to the valve hollow and provided with holes riser on which the inner bag or the membrane is first placed or wound up. This riser comes in flanging or flanging the lid into the interior of the container blank. After flanging or crimping of the plate, the material is filled through the Ventilstem with a pressure which is greater than the prevailing in the container blank internal pressure of the propellant in the inner bag or the membrane. When the said riser is used, the material flows through the valve stem into the riser and inflates the inner bag via the holes in the riser.
4. 4) An inner bag or "can-in-α-can" pressure vessel, with valve, can be filled as follows: First, the inner bag or inner can, which may be unfilled or already filled, enters the interior of the container blank brought in. A valve is at most only loose, at least not liquid-tight, with its valve plate placed on the edge of the container blank, or is held at a very short distance above the edge of the container blank. About the container blank and possibly loosely seated valve plate from above a filling device is placed on the principle of a bell, which rests from the outside in a fluid-tight manner on the outer wall of the container blank, which can be achieved by a corresponding seal. Since the valve disk does not rest tightly on the edge of the container blank, the pressurized propellant can then be introduced into the interior of the container blank by means of the filling device through the non-fluid-tight gap between the valve disk and the edge of the container blank. After filling the interior with the propellant, the valve disk must be connected in a gastight manner to the edge of the container blank, which typically takes place by means of a seal arranged in the valve disk and again by crimping over the edge of the valve disk. If this is done, if the inner bag or the inner box was not already filled with the material to be sprayed, filling with the material can be carried out through the valve stem.
5. 5) When a container with a piston is used as a separator, a cylindrical container blank that is up to and optionally already has a valve but whose bottom is still open can also be used. Here is first in the inverted container blank filled a predetermined amount of the goods, then the piston is pushed down to a desired depth in the blank. Then, a suitable amount of the blowing agent is introduced and flanged onto the lower end of the container blank under pressure a container bottom.

Some of the blowing agents which can be used in the pressure vessels according to the invention are themselves new and are therefore also the subject of the present invention. These are blowing agents consisting of: a) a gas phase comprising carbon dioxide, and b) a liquid phase comprising more than 90% by weight, based on the liquid phase, of a polyethylene glycol and dissolved carbon dioxide, with the proviso that the compound is not polyethylene glycol 400.

The statements made above regarding preferred molecular weight ranges and the contents of polyethylene glycol in the liquid phase are also applicable to the novel blowing agents.

• Figur 1 zeigt einen zylindrischen Aerosolbehälter mit einer Aussenwand 1 aus Aluminiumblech, der in seinem Innenraum einen Innenbeutel 2 aufweist, der den Innenraum in eine Vorratskammer 3 und eine Treibmittelkammer 4 unterteilt. Die Treibmittelkammer 4 enthält ein erfindungsgemässes Treibmittel. Dieses besteht aus einer gasförmigen Phase 5 mit einem Gesamtdruck in der Gasphase von typisch etwa 5 bar, wobei das Verhältnis Partialdruck Kohlendioxid zu Gesamtdruck etwa 0,98 betragen kann, und aus einer flüssigen Phase 6, die im Wesentlichen aus Polyethylenglykol mit M_w 300 und darin gelöstem Kohlendioxid besteht. Die Vorratskammer 3 ist mit einem flüssigen Gut 7 gefüllt, das mittels eines üblichen Ventils (in der Figur nicht gezeigt) und mittels eines üblichen Sprühkopfs 8 aus dem Aerosolbehälter versprüht werden kann. Links ist der gefüllte Aerosolbehälter gezeigt, rechts der Aerosolbehälter nach weitgehender Entleerung, wobei sich die Membran 2 nach oben zusammengezogen hat.
• Figur 2 zeigt einen erfindungsgemässen Aerosolbehälter mit einer Aussenwand 1 aus nichtrostendem Stahlblech. Sein Innenraum ist mittels eines Innenbeutels 2 in eine Vorratskammer 3 und eine Treibmittelkammer 4 unterteilt. Die Vorratskammer 3 ist mit einem feinteiligen Gut 9 gefüllt (etwa einem Trockenpulver von inhalierbarer Teilchengrösse). Die Treibmittelkammer 4 enthält ein Treibmittel, das aus einer Gasphase 5 und einer flüssigen Phase 6 besteht. Die Gasphase weist einen Gesamtdruck von typisch etwa 4 bar auf, wobei das Verhältnis Partialdruck Kohlendioxid zu Gesamtdruck etwa 0,99 betragen kann. Die flüssige Phase 6 besteht im Wesentlichen aus PEG mit M_w 250 und darin gelöstem Kohlendioxid. Bei dieser Ausführungsform weist der Innenbeutel 2 in seinem Inneren ein hohles Steigrohr 10 mit Durchtrittsöffnungen 11 auf. Beim Komprimieren und/oder Zusammenfalten des Innenbeutels 2 (rechte Seite der Figur 2) wird das zu versprühende Gut 9 durch die Öffnungen 11 in das Steigrohr 10 gedrückt; das Steigrohr 10 führt zu dem im Inneren des Sprühkopfs 8 angeordneten nicht sichtbaren Ventil.
• Figur 3 zeigt einen erfindungsgemässen Aerosolbehälter mit einer Aussenwand 1 aus nichtrostendem Stahlblech. Der Innenraum des Aerosolbehälters ist mittels eines Kolbens 12, der etwa aus PVC bestehen kann, in eine Vorratskammer 3 und eine Treibmittelkammer 4 unterteilt. Diese Ausführungsform des Aerosolbehälters weist über mindestens einen Teil der Länge der Mittelachse einen konstant geformten, vorzugsweise zylindrischen Querschnitt auf. In der Figur ist die Mittelachse als gestrichelte Linie gezeigt. Der Kolben 12 ist passgenau zum Querschnitt des Innenraums. Die Vorratskammer enthält ein flüssiges zu versprühendes Gut 7. Die Treibmittelkammer 4 enthält ein Treibmittel, das aus einer Gasphase 5 und einer flüssigen Phase 6 besteht. Die Gasphase weist einen Gesamtdruck von typisch etwa 4 bar auf, wobei das Verhältnis Partialdruck Kohlendioxid zu Gesamtdruck etwa 0,95 betragen kann. Die flüssige Phase 6 besteht im Wesentlichen aus dem Dibutylether eines Polyethylenglykols, der ein M_w von etwa 350 aufweist, und darin gelöstem Kohlendioxid. Auf dem Kopf des Aerosolbehälters ist ein Sprühkopf 8 angebracht, der in seinem Inneren ein Auslassventil aufweist (in der Figur nicht gezeigt). Rechts ist in Figur 3 gezeigt, wie das Volumen der Vorratskammer 3 sich durch Heraufschieben des Kolbens 12 sich verringert hat.
• Figuren 4 bis 6 zeigen die Abhängigkeit des Drucks in der Treibmittelkammer von der Temperatur, wenn die flüssige Phase PEG mit M_w 300 oder PEG-Dibutylether enthält. Für diese Messungen wurden als simulierte Treibmittelkammer plastifizierte Glasflaschen von 100 ml Volumen verwendet. Diese wurden zunächst geclincht und evakuiert, in die evakuierten Glasflaschen wurde die flüssige, noch kohlendioxidfreie Phase des Treibmittels (etwa 10 g) mit einer Spritze injiziert. Anschliessend wurde unter Schütteln die gewünschte Menge CO₂ von der Gasflasche in die Glasflaschen gegeben, bis nach Äquilibrierung bei 25°C der gewünschte Ausgangsdruck erzielt war. Es wurden drei verschiedene Ausgangsdrücke gewählt (Figur 4: 2,5 bar; Figur 5: ca. 5 bar; Figur 6: 7 bar). Der Druck wurde bei verschiedenen Temperaturen gemessen. -15°C wurde in einer Salzlösung, die zuvor im Tiefkühler gekühlt wurde, erreicht. 8°C wurden durch Äquilibrierenlassen im Kühlschrank erzielt. Auf die Temperaturen von 20°C, 25°C, 30°C, 40°C und 50°C wurden die Glasflaschen jeweils in einem Wasserbad temperiert. Der nach Äquilibrierung vorhandene Druck wurde mittels eines Handmanometers gemessen.

With reference to the figures, specific embodiments of the pressure vessel according to the invention will now be described.

• FIG. 1 shows a cylindrical aerosol container with an outer wall 1 of aluminum sheet, which has in its interior an inner bag 2, which divides the interior into a storage chamber 3 and a propellant chamber 4. The propellant chamber 4 contains a propellant according to the invention. This consists of a gaseous phase 5 with a The total gas phase pressure is typically about 5 bar, the ratio of partial pressure carbon dioxide to total pressure may be about 0.98, and a liquid phase 6 consisting essentially of polyethylene glycol having M _w 300 and carbon dioxide dissolved therein. The storage chamber 3 is filled with a liquid Good 7, which can be sprayed by means of a conventional valve (not shown in the figure) and by means of a conventional spray head 8 from the aerosol container. On the left, the filled aerosol container is shown, on the right, the aerosol container after extensive emptying, with the membrane 2 has contracted upwards.
• FIG. 2 shows an inventive aerosol container with an outer wall 1 of stainless steel. Its interior is divided by means of an inner bag 2 in a storage chamber 3 and a propellant chamber 4. The storage chamber 3 is filled with a finely divided Good 9 (about a dry powder of inhalable particle size). The propellant chamber 4 contains a propellant which consists of a gas phase 5 and a liquid phase 6. The gas phase has a total pressure of typically about 4 bar, wherein the ratio of partial pressure carbon dioxide to total pressure may be about 0.99. The liquid phase 6 consists essentially of PEG with M _w 250 and dissolved carbon dioxide therein. In this embodiment, the inner bag 2 in its interior a hollow riser 10 with through openings 11. When compressing and / or folding the inner bag 2 (right side of the FIG. 2 ) is pressed to be sprayed Good 9 through the openings 11 in the riser 10; the riser 10 leads to the non-visible valve located inside the spray head 8.
• FIG. 3 shows an inventive aerosol container with an outer wall 1 of stainless steel. The interior of the aerosol container is divided into a storage chamber 3 and a propellant chamber 4 by means of a piston 12, which may be made of PVC . This embodiment of the aerosol container has over at least a portion of the length of the central axis of a constantly shaped, preferably cylindrical cross-section. In the figure, the central axis is shown as a dashed line. The piston 12 is precisely matched to the cross section of the interior. The storage chamber contains a liquid to be sprayed Good 7. The propellant chamber 4 contains a propellant, which consists of a gas phase 5 and a liquid phase 6. The gas phase has a total pressure of typically about 4 bar, wherein the ratio of partial pressure carbon dioxide to total pressure may be about 0.95. The liquid phase 6 consists essentially of the dibutyl ether of a polyethylene glycol having an M _w of about 350 and carbon dioxide dissolved therein. On the head of the aerosol container, a spray head 8 is mounted, which has in its interior an outlet valve (not shown in the figure). Right is in FIG. 3 shown how the volume of the storage chamber 3 has been reduced by pushing up the piston 12.
• FIGS. 4 to 6 show the dependence of the pressure in the propellant chamber on the temperature when the liquid phase contains PEG with M _w 300 or PEG dibutyl ether. For these measurements, plasticized glass bottles of 100 ml volume were used as the simulated propellant chamber. These were first clinched and evacuated, in the evacuated glass bottles, the liquid, still carbon dioxide-free phase of the propellant (about 10 g) was injected with a syringe. Subsequently was shaking the desired amount of CO ₂ from the gas bottle in the glass bottles, until after equilibration at 25 ° C, the desired output pressure was achieved. Three different outlet pressures were selected (FIG. 4: 2.5 bar; FIG. 5 : about 5 bar; Figure 6: 7 bar). The pressure was measured at different temperatures. -15 ° C was achieved in a saline solution, which was previously cooled in the freezer. 8 ° C was achieved by equilibration in the refrigerator. At the temperatures of 20 ° C, 25 ° C, 30 ° C, 40 ° C and 50 ° C, the glass bottles were each tempered in a water bath. The equilibrium pressure was measured using a handheld pressure gauge.

The same experimental setup as used for FIGS. 4 to 6 also makes it possible, at a given, constant temperature, to determine the dependence of the pressure in the gas phase on the total amount of carbon dioxide supplied. For example, it was found for PEG 300 at 25 ° C: P (T = 25 ° C) [bar] 3 4.75 7 wt% (CO ₂ ) 1.6 2.8 4.0 x _{CO 2} 0.0998 .1641 .2212

With the P / x _{CO 2} Values from the above table can be determined for PEG 300 by means of linear regression H and H ₀ for the above-mentioned formula (2).

FIGS. 7 and 8th show the measured dependence of the pressure P in the propellant chamber of inventive aerosol containers (spray cans) as a function of sprayed Volume ΔV. The respective still carbon dioxide-free liquid phase was in a mixing cylinder, which withstands a maximum pressure of 10 bar, presented and sealed. The liquid phase was treated with CO ₂ via a plug valve with integrated tap. To completely saturate the liquid phase with CO ₂ , CO _{2 was} admitted until a pressure of 10 bar was in the mixing cylinder. The valve was closed and the measuring cylinder shaken vigorously until the pressure remained constant even with shaking. Subsequently, CO _{2 was} admitted again. This process was repeated until the desired pressure in the mixing cylinder was not exceeded even after shaking. Subsequently, the previously prepared blowing agent containing about 5 weight percent carbon dioxide was pumped without gas phase with a pump in the filling machine ("Pamasol" product filler) and filled into commercial cans with inner bag. The nominal volume of the cans was 118 ml each, the volume of their inner bag was 60 ml and the filled amount of propellant was 12 g per can. To simulate a canned contents to be sprayed, water was filled into the inner bag with the product filler. The final initial pressure in the cans is in the FIGS. 7 and 8th visible as y-intercept. Subsequently, the water was sprayed from the can and the pressure was measured as a function of the mass loss of the spray can (1 g mass loss = 1 ml of sprayed volume) and graphically applied.

Claims (19)

1. Pressure vessel for receiving a pressurized substance (7, 9) in gaseous, liquid or finely particulate form, said pressure vessel comprising a wall (1) with an inner wall face that defines an interior space of the pressure vessel; a separating part (2, 12) located in the interior space and dividing the interior space into a storage chamber (3) and into a propellant chamber (4), wherein the storage chamber contains the substance (7, 9) and the propellant chamber (4) contains a propellant, wherein the separating part (2, 12) is able to permit liquid-tight division into storage chamber (3) and propellant chamber (4) and, under the action of the propellant, is able to vary the volume ratio between storage chamber (3) and propellant chamber (4) in favour of the propellant chamber (4); and wherein the pressure vessel is characterized in that the propellant consists of:

   a) a gas phase (5) comprising carbon dioxide, and

   b) a liquid phase (6) comprising a compound chosen from the polyethylene glycols and their (C₁-C₄) monoethers and (C₁-C₄) diethers, and comprising carbon dioxide dissolved therein.
2. Pressure vessel according to claim 1, wherein the separating part is an extensible and/or foldable inner bag (2) which, by contraction and/or folding, is able to vary the volume ratio between storage chamber (3) and propellant chamber (4).
3. Pressure vessel according to claim 1, wherein the interior has a central axis and, extending along at least a part of the length of this central axis, which part is continuous, has a cross section that is constant in terms of its shape and surface area and that is perpendicular to the central axis, and wherein the separating part is a movable piston (12) which bears with an exact fit on the inner wall face and, by means of movement along said part of the central axis, is able to vary the volume ratio between storage chamber (3) and propellant chamber (4).
4. Pressure vessel according to one of the preceding claims, wherein at least a part of the interior has a cylindrical shape.
5. Pressure vessel according to one of claims 1 to 4, characterized in that the total amount of polyethylene glycol and polyethylene glycol monoether and polyethylene glycol diether and dissolved carbon dioxide in the liquid phase (6) amounts to more than 90 percent by weight, more preferably at least 95 percent by weight, and particularly preferably at least 98 percent by weight, relative to the liquid phase (6).
6. Pressure vessel according to one of claims 1 to 5, characterized in that the polyethylene glycol or the polyethylene glycol monoether or the polyethylene glycol diether has a M_w in the range of 200 to 600, more preferably of 200 to 390, and particularly preferably of approximately 300.
7. Pressure vessel according to one of claims 1 to 6, characterized in that the liquid phase comprises a polyethylene glycol or a polyethylene glycol 1,4-dibutyl ether.
8. Pressure vessel according to one of claims 1 to 7, characterized in that in the gas phase (5) of the propellant the ratio of the partial pressure of carbon dioxide to the total pressure is at least 0.90, more preferably at least 0.95, and particularly preferably at least 0.98.
9. Pressure vessel according to one of claims 1 to 8, characterized in that it is able to dispense the substance from the storage chamber (3) in a controlled manner by means of a valve.
10. Pressure vessel according to claim 9,
    characterized in that it is able to spray the substance by means of a spray head (8).
11. Pressure vessel according to claim 10,
    characterized in that it is an aerosol container.
12. Pressure vessel according to one of claims 1 to 8, characterized in that it is a cartridge.
13. Propellant, consisting of

    a) a gas phase (5) comprising carbon dioxide, and

    b) a liquid phase (6) comprising more than 90 percent by weight, more preferably at least 95 percent by weight, and particularly preferably at least 98 percent by weight, relative to the liquid phase (6), of a polyethylene glycol, and carbon dioxide dissolved therein;

    with the proviso that the polyethylene glycol is not polyethylene glycol 400.
14. Propellant according to claim 13, wherein the polyethylene glycol is a polyethylene glycol with a M_w in the range of 200 to 600, more preferably of 200 to 390, and particularly preferably of 300.
15. Propellant according to claim 13 or 14, wherein the proportion of polyethylene glycol and dissolved carbon dioxide in the liquid phase (6) amounts to more than 90 percent by weight, more preferably at least 95 percent by weight, and particularly preferably at least 98 percent by weight, relative to the liquid phase (6).
16. Propellant according to one of claims 13 to 15, wherein the polyethylene glycol is a polyethylene glycol with a M_w in the range of 200 to 600, more preferably of 200 to 390, and particularly preferably of approximately 300.
17. Propellant according to one of claims 13 to 16, wherein in the gas phase (5) the ratio of the partial pressure of carbon dioxide to the total pressure is at least 0.90, more preferably at least 0.95, and particularly preferably at least 0.98.
18. Method for controlled dispensing of a substance in gaseous, liquid or finely particulate form, characterized in that the substance is provided in the storage chamber (3) of a pressure vessel according to one of claims 1 to 10, and the substance is dispensed from the storage chamber (3) of the pressure vessel in a controlled manner by means of a valve.
19. Method according to claim 18, wherein the substance is sprayed by means of a spray head.

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