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directing the obtained liquid mixture into an aerosol can, providing the propellant and polyurethane and epoxy resins into the can and sealing the can to obtain a paint forming dispersion inside the can, 

wherein in said method the amount of weak acid is adapted so that it can catalyze in the reaction (2; 2a2) the formation of the polyurethane hardener precursors and epoxy hardener precursors from polyurethane hardeners and epoxy hardeners in the presence of free water (H$_{2}$ 0) in the liquid mixture 

and also to catalyze the reaction (2; 2a2) by shifting the equilibrium of the reversible reaction (2a; 2a2), in alternative pathways A or B, between the free water present in said paint forming dispersion and polyure› thane hardener precursors and epoxy hardener precur› sors back to formation of said initial polyurethane hardener and epoxy hardener and wherein 

an additional amount of polyurethane hardener precursor and epoxy hardener precursor can be added to prepare said liquid mixture for replacing the polyurethane hard› ener precursor and epoxy hardener precursor which has been consumed for reacting with water. 

19. The method defined in any of the previous claims 15-18, characterized in that, the method comprises addition› ally step of using the aerosol can by spraying the paint forming dispersion out of the can to form a dry paint film having a surface gloss of 5-100 preferable 10-100. 

20. The method defined in claims 19, characterized thereof, that the using the can comprises spraying the paint forming dispersion out from the can for enabling water, such as humidity, present in the surrounding environment to react with the polyurethane hardener precursor and with the possible epoxy hardener precursor to form a hardener com› pound with the amine and possible also with the hydroxyl functionality and then to form on the target surface the dry paint film. 

21. The method according to claim 19 or 20, characterized thereof, that weak acid (XCOOH) is added into paint form› ing dispersion an amount which will enable, after using the can by spraying the paint forming dispersion from the can, to enable to form a dry paint film having gloss in the range of 10-100 from said paint forming dispersion and also contribute to a higher adhesion to the paint surface by etching method. 

22. The method defined in any of the claims 19-21, characterized thereof that the dry paint film is transparent and have a gloss in the range of 10-100 preferable over 90, under an angle of 60°. 

23. The method defined in any of the claims 19-22, characterized thereof, that the dry paint film have the Konig› hardness over 40 after 10 h and over 100 after 120 h of drying-time, measured with pendel hardness meter. 

24. The method defined in any of the claims 19-23, characterized thereof, that the adhesion of the dry paint film is >450 psi, in PosiTest. 

25. The method defined any of the claims 19-22, charac› terized in that, the Konig-hardness of the dried paint film is over 40 after 10 h of drying time of the sprayed paint film. 

26. The paint forming, pressurized dispersion in a sealed aerosol can said dispersion having an extended shelf life, wherein said dispersion have been prepared with a method defined in any of the claims 15-18 for providing a paint forming dispersion comprising a polyurethane resin and a possible epoxy resin, a polyurethane hardener precursor, ketones, possible organic solvent8s), pigments, paint addi› tives, dispersion additives, propellant and providing along› side with said paint forming chemicals additionally 1-10000 ppm of free water into said sealed can; 

characterized in that, the 

polyurethane resins are selected from the group which composes of MDI, HDI, IPDI, TDI and phenol blocked TDI prepolymers, 

polyurethane hardener precursors, are selected from the group consisting of an imine, an enamine, a Mannich base, a Schiff’s base, aldimine, an azole preferable an oxazole such as an oxazolidine and mixtures thereof; 

for extending the shelf life of the dispersion, the amount of weak acid is adapted on the basis ofH$_{2}$ 0 (free water) present in the can, the amount of the weak acid being in the range of 0.01-10% by weight (w/w) of the aerosol formulation, preferably from 0.1 to 5%, still more preferably from 0.25 to 2%;, which weak acid is selected from the group which have the pKa value in the range from 1.2 to 9.9 preferable 1.2-5.2; 

additionally also temporary hydrolyzed products of said polyurethane hardener precursors and possible epoxy precursors are present in said dispersion, which hydro› lyzed products originate to the reversible reaction (2a; 2al) or (2a; 2a2) catalyzed by said the weak acid 

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the amount of polyurethane hardener precursors and pos› sible epoxy hardener precursor, polyurethane resin, possible epoxy resin, free water, ketones, propellant and possible organic solvent, possible pigments is at least 95% w/w from the total volume of the paint forming solution and the rest of said solution composes of the paint additives and dispersion additives. 

27. The paint forming, pressurized dispersion defined in claim 26, characterized thereof, that the paint forming dispersion is provided by admixing alongside with the polyurethane resin and polyurethane hardener precursor also epoxy resins and epoxy hardener precursors and wherein said the weak acid catalyzes the reversible reaction (2a; 2a2) between the free water present in said dispersion and poly- 

