Increasing and maintaining the hydrophilic nature of an oxidized plastic surface

A method of preventing the formation of coating defects in polymeric coated organic surfaces in a coating process comprising a plurality of steps, which steps occur prior to the polymeric coating of the surfaces and, which steps contact polymeric organic surfaces and metal surfaces, to which metal surfaces uncured resin particles have been applied, with a plurality of aqueous compositions in which resin particles released from the metal surfaces accumulate in suspension, the steps comprising:

• (1) oxidizing the polymeric organic surfaces to form an oxidized organic surface;
• (2) waiting for a period of time after forming the oxidized organic surface and then treating the oxidized organic surface with an aqueous treatment solution comprising water-soluble and/or water dispersible polyphenol resin;
• (3) contacting the oxidized treated surfaces with the plurality of aqueous compositions containing the particles;
• and
• (4) removing the surfaces from the plurality of aqueous compositions.

In a process for the assembly line coating of an assembly of parts comprising metal surfaces and polymeric organic surfaces, the process comprising the application of a hydrophobic sealer resin onto portions of metal surface parts combined in the assembly, contacting the assembly with a plurality of aqueous compositions, applying one or more finish coatings to the metal surfaces and polymeric organic surfaces of the assembly, and curing the coating, the improvement comprising:

• (1) oxidizing the surfaces of the polymeric organic surface parts;
• (2) treating the oxidized organic surfaces with a water soluble amine containing resin composition, wherein the resin has at least 10 amine groups per molecule and a number average molecular weight of at least 1000 g/mole;
• (3) contacting the assembly, comprising the oxidized treated organic surface parts and the metal parts on which hydrophobic sealer resin has been applied, with a plurality of the aqueous compositions;
• (4) after contacting the aqueous compositions with the assembly, recovering the plurality of aqueous compositions;
• and
• (5) reusing the plurality of aqueous compositions with additional assemblies comprising the oxidized organic surface parts and the metal parts having metal surfaces on which hydrophobic sealer resin has been applied.

A method of increasing and maintaining the hydrophilicity of an organic surface, the method comprising:

• producing a flame-treated organic surface;
• waiting for a first period of time;
• coating the flame-treated organic surface by applying a post-treatment solution coating, the solution comprising an aminosaccharide derivative polyphenol resin;
• and
• waiting for a second period of time, wherein the flame-treated organic surface having the coating retains a hydrophilicity range of 50-100% when measured by the full sheeting water test.