US 2020/0190338 Al  2  Jun. 18,2020  DESCRIPTION OF THE INVENTION  [0028]  This inventive two-component aerosol paint and  adhesive system have a long shelf life, is simple to manu- [0027]  The present invention provides a method for pre› venting hardener compounds to be formed from hardener  precursors and extending the shelf life of the dispersion in  the sealed can as depicted by claims  1  and  2,  the method for  preparing said dispersion into the sealed can as depicted in  claims  15  and  16  and also a paint forming, pressurized  dispersion in a sealed aerosol as depicted by claim  24.  [0018]  For example, the abstract of JP2004035947 dis› closes a two component aerosol formulation for an aerosol  can. The formulation comprises an epoxy resin such as  bisphenol A type, an imine as hardener precursor and a  propellant. The drawback and challenge in this type of  solution is typically the presence of moisture in the aerosol  formulation causing premature hardening already in the can.  Therefore, zero ambient moisture for the precursors and the  packaging ambient is a key requirement. Additionally, in this  patent document it has been proposed that ensuring the dry  conditions should be done by adding water scavengers. As  mentioned above adding water scavengers will prevent  forming hardener compounds prematurely because it will  affect to imine-keton balance in reactions (2a) and (2b ).  However, the addition of water scavengers will affect nega› tively to paint quality and therefore the primary use of the  disclosed two component aerosol of this kind is as a primer  with gloss <5.  [0026]  This second main objective means also that method  to be used should enable making a wide range of paints with  high gloss, lacquers or varnishes with high transparency,  adhesives and primers with good adhesion and paints with  good surface hardness and resistance to corrosion. In this  connection should be noted that especially solid water  scavengers will reduce the corrosion resistance; primers  cannot be used as surface paints, because they include fillers  (solid water scavengers) and a primer film will thus pass  water. In a case an epoxy paint contains solid water scav› engers, the water can remain inside the epoxy paint when the  paint film is formed. This can cause corrosion problems.  [0025]  This second objective means that the objective of  the present invention was to prevent polyurethane hardener  compounds to be formed from polyurethane precursor in the  polyurethane based two-component aerosol paint and adhe› sive system, without affecting negatively to the quality of the  paint to be manufactured from said aerosol formulation.  [0024]  The second main object of the present invention  was to control reaction equilibrium between t the polyure› thane hardener precursors and polyurethane hardeners  (amines) presented in reactions la-le, so that it will also  enable making high quality paints and primers.  [0017]  In the prior art the inventors have added big  amounts of water scavengers to control the formation of  epoxy or polyurethane hardeners in the above mentioned  reaction (la) between imine and water. Removing water  with scavengers also shifts reaction (1 b) into formation of  more imines. The amount of water scavengers used to  control reactions la and lb have been so high that it has  deteriorated the quality of coating to be achieved. Use of  water scavengers will tend to prevent making high quality  paints because surface of paint film will remain soft or brittle  and making a clear coat high gloss or a colour high gloss is  also impossible if high amount of water scavengers are used  in an aerosol formulation to control formation of epoxy  hardeners. Therefore, good quality paints cannot be prepared  from these known one-can-two-component-aerosol-formu› lation(s).  [0023]  Especially object of the present invention was to  provide an aerosol dispersion in a sealed and pressurized  aerosol can, which would be stable for a long time period  and which would enable successful reuse after initial first  usage anytime within at least a year, preferable at least three  years.  [0022]  The first main object of the present invention was  to provide a polyurethane resin based aerosol dispersion,  such as paint and adhesive system, that has a good stability  and a long shelf life in a sealed aerosol can.  [0021]  Based on the above presented prior art there was a  general need for a polyurethane based two-component aero› sol paint and adhesive system wherein an extended shelflife  could be achieved without relying on the use of water  scavengers, especially solid water scavengers whose use  have proven problematic.  [0020]  The target of the present invention was to remove  drawbacks of the prior art mentioned above.  [0016]  By removing water from the right side of the  hydrolyzing reaction (la) or by removing water from elimi› nating stage in condensing reaction (1 b) with water scav› engers, one can either prevent the amines (epoxy or poly› urethane hardener compounds) to be formed in reaction (la)  or to shift reaction equilibrium (1 b) to favor forming imines  ( epoxy or polyurethane hardener precursors) instead of  amines ( epoxy or polyurethane hardeners).  [0015]  Which can also be presented as a reversible reac› tion equilibrium:  [0019]  Patent document JP2004035947 discloses also an  epoxy resin based two component aerosol formulation,  which can be used in an aerosol can, wherein the epoxy resin  and a hardener are mixed extended time in the same room of  the aerosol can before manufacturing the paint or lacquer.  However, also this patent document uses water scavengers  to remove excess water from aerosol. These scavengers will  make it impossible to achieve commercial 2K paints with  high gloss and therefore this two component aerosol is  suitable only to making primers.  -continued  or  Amine  Ketone  (epoxy or polyurethane  hardener)  (epoxy or  polyurethane  hardener  precursor)  (lb)  Amine  Ketone  (epoxy or polyurethane  hardener)  imine  ( epoxy or polyurethane  hardener precursor)  (le) 