Protective water reversible clear coating for substrates
A protective water reversible clear coating composition for the protection of substrates comprised of water, a volatile base, a film-forming acrylic polymer in a water dispersion form, a second film-forming polymer, specifically poly (2-ethyl-2-oxazoline) that is miscible with the first dispersed acrylic polymer, a poly acidic material (pH specific in terms of its solubility properties), and an alkaline swellable thickener that also can be water soluble as a function of pH and wherein said coating is both water applied and water reversible or re-soluble under specific pH conditions.
1. A composition comprising: an aqueous medium, a volatile base, an acrylic film forming polymer, a polyoxazoline, and a poly acidic polymer, said poly acidic polymer comprising between 0.1-10% of the total weight of the composition, said acrylic film forming polymer comprising between 30-60% of the total weight of the composition and said polyoxazoline comprising between 20-50% of the total weight of the composition, and wherein said composition is capable of being applied to a substrate using aqueous means and removed from said same substrate using an aqueous buffer at a pH between 6 and 10.
2. The composition of claim 1 further comprising one or more of the following: a swellable thickener, a UV stabilizer, a coalescence material, a de-foaming agent, an anti-microbial agent, a colorant, an agent to protect from temperature swings, and a flattening agent.
3. The composition of claim 2 wherein said swellable thickener is an alkali swellable carboxylated polymer.
4. The composition of claim 1 wherein said acrylic film forming polymer is in an aqueous dispersion and selected from the group consisting of: acrylic emulsions, styrene/acrylic emulsions, or combinations thereof.
5. The composition of claim 1 wherein said polyoxazoline is poly (2-ethyl-2-oxazoline).
6. The composition of claim 1 wherein said poly acidic polymer is an acrylic resin comprising at least one vinyl or vinylidene moiety having a carboxylic acid group capable of salt formation.
7. The composition of claim 1 wherein said poly acidic polymer is selected from the group consisting of: methacrylic acid-methyl methacrylate copolymer (1:1), methacrylic acid-methyl methacrylate copolymer (1:2), methacrylic acid-ethyl acrylate copolymer (1:1), or combinations thereof.
8. The composition of claim 1 , wherein said polyacidic polymer is a co-polymer consisting of monomers of both methacrylic acid and a second monomer of either methyl methacrylate or ethyl acrylate, or combinations thereof, and wherein the ratio of said co-monomers in the polyacrylic acid determines the pH at which the poly acidic polymer will be soluble in an aqueous buffer, and wherein the disruption and removal of a coating will be a function of pH, wherein the disruption and removal of said coatings is within a pH range of between 6-10.
9. A method of coating a substrate with a removable composition comprising:
a. forming a composition comprising: water, a volatile base, an acrylic film forming polymer, polyoxazoline, and a poly acidic polymer, wherein the percentage composition by weight is between 30-60% of the acrylic film forming polymer, between 20-50% of the polyoxazoline, and between 0.1-10% of the poly acidic polymer,
b. coating said substrate with said composition, and
c. allowing said composition to dry, wherein said dried composition is capable of being re-solubilized using an aqueous buffer having a pH of between 6 and 10.
10. The method of claim 9 further comprising one or more of the following: a swellable thickener, a UV stabilizer, a coalescence material, a de-foaming agent, an anti-microbial agent, a colorant, an agent to protect from temperature swings, and a flattening agent.
11. A method of coating a substrate comprising:
a. applying a first layer of a composition comprising: water, a volatile base, an acrylic film forming polymer, a polyoxazoline, and a poly acidic material, wherein the percentage composition by weight of the first layer of a composition is between 30-60% of the acrylic film forming polymer, between 20-50% of the polyoxazoline, and between 0.1-10% of the poly acidic polymer said first layer capable of being re-solubilized using an aqueous buffer having a pH of between 7 and 10;
b. applying a second layer of a second composition having a distinct re-solubilizing property from said first layer of a composition, comprising: water, a volatile base, an acrylic film forming polymer, a polyoxazoline, and a poly acidic material, said second layer capable of being re-solubilized using an aqueous buffer having a pH of between 6 and 10; and
c. wherein said first and second compositions are capable of being re-solubilized using an aqueous buffer with a different pH, having a difference of at least 0.5 pH.
12. The method of claim 11 wherein said first layer is capable of being re-solubilized using an aqueous buffer having a pH of about 1.0 unit greater than said second adjacent layer.
13. The method of claim 11 wherein said first layer is capable of being re-solubilized using an aqueous buffer having a pH of about 8 or more and wherein said second layer is capable of being re-solubilized using an aqueous buffer having a pH of about 7.
14. The composition of claim 11 wherein the percentage in the second composition by weight is between 30-60% of the acrylic film forming polymer, between 20-50% of the polyoxazoline, and between 0.1-10% of the poly acidic polymer.
15. The method of claim 11 further comprising a non-pH reversible coating applied to the substrate prior to the application of the first layer.
16. The method of claim 11 comprising three or more layers capable of individually being re-solubilized provided that each adjacent outer layer is re-solubilized using an aqueous buffer at a pH of about 1.0 unit lower than an adjacent inner layer.
17. The method of claim 9 or 11 wherein the polyoxazoline is poly (2-ethyl-2-oxazoline).