AEROSOL CAN CONFIGURATION

Abstract

An aerosol can configuration includes an outer can, an inner container and a spray head with a discharge element. The spray head has an outlet valve connected to the interior of the outer can and an outlet valve connected to the interior of the inner container. The two outlet valves are opened jointly by pressing on the spray head, so that the contents of the outer can and the contents of the inner container jointly enter the discharge element. To form a foam, the outer can contains at least 30-70% by weight isocyanate, in particular diphenylmethane 4,4′-diisocyanate, 3-15% by weight polyol with an OH number of less than 300, and 5-30% by weight liquid gas at a critical temperature of ≥+70° C. At least 5-30% by weight polyol with an OH number of more than 300, and 1-10% by weight liquid gas with a critical temperature of ≥+70° C. are contained in the inner container.

Claims

1. A method of creating a foam barrier in a pipe to create a hydraulic seal, comprising: spraying at least one first component and at least one additional component into the pipe to create a foam barrier, in which; the first component includes isocyanate and a liquid gas, and the at least one additional component includes a polyol and a liquid gas; wherein the foam barrier is formed by a urethane reaction of the first component with the at least one additional component.

2. The method of claim 1, wherein: the first component includes at least 30% to 70% by weight (wt %) isocyanate and 5% to 30% by weight liquid gas at a critical temperature of ≥+70° C., and the at least one additional component includes at least 5% to 30% by weight polyol with OH number of more than 300 and 1% to 10% by weight liquid gas with a critical temperature of ≥+70° C.;

3. The method of claim 2, wherein the isocyanate is diphenylmethane 4,4′-diisocyanate.

4. The method of claim 1, wherein the at least one component further includes: a flame retardant; and a catalyst for the urethane reaction of the isocyanate and the polyol.

5. The method of claim 4, wherein the at least one first component includes: 10% to 20% by weight flame retardant; and 0.5% to 3% by weight catalyst for the urethane reaction, and 0.5% to 3% by weight trimerization catalyst for the isocyanate.

6. The method of claim 4, wherein the flame retardant is tris(1-chloro-2-propyl) phosphate.

7. The method according to claim 2, wherein the at least one first component further includes 3% to 15% by weight polyol with an OH number of less than 300.

8. The method of claim 2 wherein the at least one first component further includes: 0.1% to 1% by weight catalyst for a prepolymer reaction between the isocyanate and the polyol, and 0.1% to 3% by weight coloring agent.

9. The method of claim 8, wherein the catalyst for the prepolymer reaction is 2,2′-dimorpholinodiethyl ether.

10. The method of claim 2, wherein the at least one first component further includes polyether-polydimethylsiloxane copolymer as a foam stabilizer.

11. The method of claim 2, wherein the at least one additional component further includes 1% to 10% by weight R152a and/or DME and/or propane-butane mixtures.

12. The method of claim 2, wherein the at least one additional component further includes at least 15 parts by weight polyol with an OH number of more than 300 per 100 parts by weight isocyanate.

13. The method of claim 2, wherein the liquid gas of the first component is 5% to 30% by weight R152a and/or DME and/or propane-butane mixtures.

14. The method of claim 1, wherein the spraying step includes providing an aerosol can configuration including; an outer can; an inner container; and a spray head provided with a discharge element, the spray head having an outlet valve connected to the interior of the outer can and an outlet valve connected to the interior of the inner container, wherein the at least one first component is contained together with at least one propellant gas in the outer can, and the at least one additional component together with at least one propellant gas is contained in the inner container, wherein the outlet valves are configured to be operated jointly by pressing on the spray head such that the contents of the outer can and the contents of the inner container can jointly enter the discharge element.

15. The method of claim 1, wherein the spraying step includes creating the foam barrier with a thickness of the foam barrier along the length of the pipe corresponding to at least 0.6 times the inside diameter of the pipe.

16. The method of claim 15, wherein the spraying step includes creating the foam barrier with a thickness of the foam barrier along the length of the pipe that is at least 0.8 times the inside diameter of the pipe.

17. A barrier in a pipe comprising: a foam is a mixture of isocyanate and polyol, formed by a urethane reaction of isocyanate and polyol within the pipe, the foam having a thickness along the length of the pipe that it at least 0.6 times an inside diameter of the pipe.

18. The barrier of claim 17, wherein the isocyanate is diphenylmethane 4,4′-diisocyanate.

19. The barrier of claim 17, wherein the mixture further includes a flame retardant.

20. The barrier of claim 19, wherein the flame retardant is tris(1-chloro-2-propyl) phosphate.

21. The barrier of claim 17, wherein the mixture further includes polyether-polydimethylsiloxane copolymer as a foam stabilizer.

Description

DESCRIPTION OF THE FIGURES

[0027] The drawings used to illustrate one embodiment are given below, in which:

[0028] FIG. 1 shows a section through an aerosol can; and

[0029] FIG. 2 shows a section through a pipe provided with a foam barrier.

DETAILED DESCRIPTION

[0030] FIG. 1 shows the important components of an aerosol can in a sectional and simplified diagram. The aerosol can comprises essentially an outer can 2, which has dimensional stability and is stable under pressure, an inner container 3 and a spray head 4. In the present example, the inner container 3 is also designed as an inner can having dimensional stability and stability under pressure. The spray head 4 is connected to the inner space 3a of the inner container 3 by means of a first channel 6 and is connected to the inner space 2a of the outer can 2 by means of a second channel 7. The spray head is also provided with two outlet valves 8, 9, which close both of the aforementioned channels 6, 7 and which can be opened jointly in a known way by pressing manually on the spray head 4. The two channels 6, 7 open into a discharge element 5 arranged on the spray head 4, the components emerging from the inner container 3 and/or the outer can 2 being combined in the discharge element and mixed together with one another. The discharge element 5 may optionally have a mixing element (not shown) which is equipped with mixing channels attached to it or the discharge element 5 itself may be provided with mixing cans (not shown).

[0031] The active ingredient components accommodated in the outer can 2 are referred to as WK1 on the whole, while the active ingredient components accommodated in the inner can 3 are referred to as WK2 on the whole. The aerosol can together with the active ingredients contained therein is referred to on the whole as aerosol can configuration 1. The aerosol can configuration 1 illustrated here has the advantage that the active ingredient components WK1, WK2 contained in the two interior spaces 2a, 3a are combined only outside of the respective container, i.e., outer can 2 and/or inner container 3, and the physicochemical reaction, by means of which the foam is formed and/or generated therefore takes place outside of the two containers 2, 3. Therefore, the aerosol can and/or the aerosol can configuration 1 is/are preferably suitable for repeated use.

[0032] Depending on the application, the inner container 3 may be made of either a flexible material or a can having dimensional stability and pressure stability. The design as a can having dimensional stability and pressure stability has the advantage that it can be filled with the active ingredient components and put under pressure by means of liquid gas, for example, in the uninstalled state. For filling the inner container 3, the interior space 3a is first filled with active ingredients, such as the curing agent. Then the valve is screwed onto the container and the container is gassed through the valve body 8. Then the interior space 2a is filled with the other active ingredient, the inner container together with the valve is inserted and locked in place. The interior space 2a is gassed through the valve body 9. Finally, the entire can is agitated.

[0033] To form a waterproof foam, by means of which a foam barrier can be created, the following components, for example, are accommodated in the respect can. The following values are each given in percent by weight (wt %) and refer to the total filling from the outer can and the inner can.

[0034] Outer Can:

TABLE-US-00001 30% to 70% diphenylmethane-4,4′-diisocyanate,  3% to 15% polyol with an OH number of less than 300,  5% to 30% liquid gas at a critical temperature of ≥+70° C., prefer- ably R152a and/or DME, 10% to 20% flame retardant, preferably tris(1-chloro-2-propyl) phosphate, 0.1% to 1%.sup.  catalyst for the prepolymer reaction, preferably 2,2′- dimorpholinodiethyl ether, 0.1% to 2%.sup.  foam stabilizer, preferably polyether-polydimethyl- siloxane copolymer.

Inner Container:

[0035]

TABLE-US-00002   5% to 30% polyol with an OH number greater than 300,   1% to 10% liquid gas with a critical temperature of ≥+70° C., preferably R152a and/or DME, 0.5% to 3% catalyst for the urethane reaction, 0.5% to 3% trimerization catalyst, 0.1% to 3% coloring agent

[0036] By discharging and mixing the listed components by means of aerosol can configuration 1 described above, a foam is produced, such that, after curing, it is suitable for filling even large-sized water pipes, i.e., pipes having a diameter of 100 millimeters or more, and creating a foam barrier that is waterproof and withstands a pressure of at least 0.1 bar. The foam comprised up of the active ingredient components indicated above will fully cure in approximately 5 to 10 minutes.

[0037] The mixing ratio is preferably 3 to 7 parts by weight WK1 to one part by weight WK2, wherein a mixing ratio on the order of magnitude of 5 to 1 has proven especially suitable. Due to the use of such a mixing ratio, it is possible to work with a different curing mechanism for the first time. As indicated below, curing of the prepolymer takes place through a combination of the known trimerization according to formula 1 and a urethane reaction according to formula 2:

##STR00001##

[0038] It can be seen from formula 1 that the curing takes place catalytically. It is therefore sufficient to add a small amount of catalyst from chamber 3a to the prepolymer and therefore it is possible to work with a mixing ratio on the order of magnitude of 10:1. However, the aforementioned mixing ratio may vary in the range between approximately 8:1 and 12:1.

[0039] For the urethane reaction according to formula 2, stoichiometrically correct amounts must be added to the prepolymer. The amount depends on the OH number of the polyol “R—OH” in formula 2. A 1:1 mixing ratio is often necessary. By developing a good formulation, it is possible to reduce this ratio to 5:1. If the flame retardant and the polyol with an OH number of less than 300 are added to the curable isocyanate, the volume is increased greatly and the mixing ratio may therefore be 5:1.

[0040] At any rate, it has been found that thorough curing of the prepolymer can be achieved by using the aerosol can configuration 1 described here. The prepolymer also cures with a consistent result radially as far as the optionally cold wall of the pipe, so that a porous interface, such as that which occurs with foams formed according to the state of the art does not develop.

[0041] FIG. 2 shows as an example a section through a pipe R provided with a foam barrier S in a simplified diagram. The foam barrier S has a thickness A corresponding to at least 0.6 times the inside diameter D of the pipe, in particular at least 0.8 times the inside diameter D of the pipe. The foam barrier S preferably has a thickness A, which corresponds at least to the inside diameter D of the pipe R. The foam barrier adheres to the inside wall of the pipe R either by adhesion or mechanical gripping along its circumference.

[0042] The foam barrier introduced into the pipe R with the aerosol can configuration described previously undergoes a curing which extends all the way to the pipe wall, so that the foam barrier is thoroughly cured and also does not form a porous interface on the pipe wall, which may be cold. The foam barrier thus forms a hydraulically continuous and dense, i.e., waterproof, seal on the pipe. Experiments have shown that at a thickness A corresponding approximately to the inside diameter D of the pipe, the foam barrier can withstand a hydraulic pressure of at least 0.1 bar. The aforementioned relationships also naturally do not apply to all pipe sizes but instead apply in particular to pipes having an inside diameter between approximately 100 mm and 500 mm. With smaller pipes, it may be sufficient in some cases to choose a thickness A, which is in the range between 0.6 times and 0.9 times the inside diameter D of the pipe R.