Water based removable paint formulation and system

Abstract

An easily removable coating or paint which is a formulation of acrylic acid polymers and a urethane polymer preferably two acrylic acid polymers are used, one with a relatively high acid number and hardness temperature (glass transition) (Tg) and the other with a lower acid number and hardness temperature (Tg). This removable paint is applied to a surface by roller, screen printing, spraying or brushing and can be removed by a remover which is basically an alkali material with a surfactant. The remover needs to be agitated and allowed to set for a few minutes and then washed away with water. Ammonium hydroxide with surfactant and acrylic thickeners in water is one remover. Another remover is a combination of more than one alkalis, solvent, surfactants and thickeners.

1 . A weather resistant, rapidly removable, removable coating composition which comprises:
 a. from about 19 to about 34% by weight of an acrylic polymer;   b. from about 0.2 to 4% by weight of an aliphatic water-borne urethane polymer; and   c. from 0.06 to 0.6% by weight of an alkali.   
     
     
         2 . The composition of  claim 1 , wherein the acrylic polymer is present in an amount of from about 22 to 30% by weight and the aliphatic water-borne urethane polymer is present in an amount from about 0.4 to 1.2% by weight and the alkali is ammonium hydroxide which is present in an amount from 0.06 to 0.3% by weight. 
     
     
         3 . The composition of  claim 1 , wherein the acrylic polymer is present in an amount of approximately 26% by weight and the aliphatic water-borne urethane polymer is present in an amount of approximately 0.7% by weight and the alkali is ammonium hydroxide which is present in an amount of approximately 0.28% by weight. 
     
     
         4 . The composition of  claim 1 , wherein the acrylic polymer (a) comprises 19 to 26% by weight of an acrylic polymer with an acid number of between 60 and 70 and a hardness temperature (Tg) of between 26° C. and 30° C. and 2.4 to 6% by weight of an acrylic polymer with an acid number of between 28 and 34 and a hardness temperature (Tg) of between 22° C. and 26° C. and the aliphatic water-borne urethane polymer (b) is present in an amount of from 0.4 to 1.2% by weight and this urethane polymer has a viscosity (cP) of from 120 to 130 and a pH of 8+/−1.5 and the alkali (c) is ammonium hydroxide present in an amount of from 0.06 to 0.6% by weight to achieve a pH of the composition of from 8 to 8.5 pH. 
     
     
         5 . The composition of  claim 1 , in which the acrylic polymer (a) comprises approximately 22% by weight of an acrylic polymer having an acid number of approximately 65 and a hardness temperature (Tg) of 28° C. and approximately 4% by weight of an acrylic polymer with an acid number of approximately 32 and a hardness temperature (Tg) of 24° C. and a urethane polymer (b) has a viscosity (cP) of approximately 125 and a pH of 8+/−1 and is present in an amount of approximately 0.7% by weight and the alkali (c) is ammonium hydroxide that is present in an amount of 0.06 to 0.6% by weight as needed to achieve a pH of the composition between 8 and 8.5. 
     
     
         6 . The composition of  claim 1  to which a dispersible pigment has been added in amount to achieve the desired color of paint. 
     
     
         7 .- 9 . (canceled) 
     
     
         10 . A method for temporarily protecting the surface of unpainted or painted articles which comprises coating the surface of the article with the composition of  claim 1 . 
     
     
         11 . A method of  claim 10  in which the acrylic polymer in the composition is present in an amount of from about 22 to 30% by weight and the aliphatic water-borne urethane polymer is present in an amount from about 0.4 to 1.2% by weight and the alkali is ammonium hydroxide which is present in an amount from 0.06 to 0.3% by weight. 
     
     
         12 . The method of  claim 10  in which the acrylic polymer in the composition is present in an amount of approximately 26% by weight and the aliphatic water-borne urethane polymer is present in an amount of approximately 0.7% by weight and the alkali is ammonium hydroxide which is present in an amount of approximately 0.28% by weight. 
     
     
         13 . The method of  claim 10  in which the acrylic polymer (a) in the composition comprises 19 to 26% by weight of an acrylic polymer with an acid number of between 60 and 70 and a hardness temperature (Tg) of between 26° C. and 30° C. and 2.4 to 6% by weight of an acrylic polymer with an acid number of between 28 and 34 and a hardness temperature (Tg) of between 22° C. and 26° C. and the aliphatic water-borne urethane polymer (b) is present in an amount of from 0.4 to 1.2% by weight and this urethane polymer has a viscosity (cP) of from 120 to 130 and a pH of 8+/−1.5 and the alkali (c) is ammonium hydroxide present in an amount of from 0.06 to 0.6% by weight to achieve a pH of the composition of from 8 to 8.5 pH. 
     
     
         14 . The method of  claim 10  in which the acrylic polymer (a) in the composition comprises approximately 22% by weight of an acrylic polymer having an acid number of approximately 65 and a hardness temperature (Tg) of 28° C. and approximately 4% by weight of an acrylic polymer with an acid number of approximately 32 and a hardness temperature (Tg) of 24° C. and a urethane polymer (b) has a viscosity (cP) of approximately 125 and a pH of 8+/−1 and is present in an amount of approximately 0.7% by weight and the alkali (c) is ammonium hydroxide that is present in an amount of 0.06 to 0.6% by weight as needed to achieve a pH of the composition between 8 and 8.5. 
     
     
         15 . The method of  claim 10  which further includes adding a dispersible pigment to the composition to achieve the desired color of paint. 
     
     
         16 . The method of  claim 11  which further includes adding a dispersible pigment to the composition to achieve the desired color of paint. 
     
     
         17 . The method of  claim 14  which further includes adding a dispersible pigment to the composition to achieve the desired color of paint. 
     
     
         18 . A system for temporarily coating a surface of an article and rapidly removing the coating which comprises:
 a. coating the surface of the article with a dispersion of the coating composition of  claim 1 ; and   b. removing the coating using a coating remover concentrate composition which comprises from 1 to 5% by weight of ammonium hydroxide and 2 to 5% by weight of alkali thickeners and the balance water which is brought into contact with the coating and agitating the coating and washing the residue with water.   
     
     
         19 . The composition of  claim 6  to which reflective beads have been added to the coating as the coating is being applied to a surface. 
     
     
         20 . (canceled) 
     
     
         21 . A method for temporarily protecting the surface of unpainted or painted articles which comprises coating the surface of the article with a composition of  claim 1  and removing the coating with a remover which comprises from 0.2 to 5% by weight of alkali and thickener which is brought into contact with the coating and agitated and allowed to set for a few minutes and then washed away with water. 
     
     
         22 . The method of  claim 21  in which the remover comprises from 1 to 5% by weight of ammonium hydroxide and 2 to 5% by weight of alkali thickeners and the balance water. 
     
     
         23 . The method of  claim 21  in which the remover comprises a combination of dibasic esters and thickeners. 
     
     
         24 . A method for temporarily protecting the surface of unpainted or painted articles which comprises coating the surface of the article with a composition of  claim 1  and removing the coating with a remover which comprises an organic solvent where the pH has been adjusted as necessary to remove the paint.