Electrodeposition over non-conductive primers

Claim 2

In a method of electrocoating comprising coating an electrode in electrical contact with a counter-electrode and an aqueous medium comprising an ionically solubilized synthetic organic resin by passing an electric current between the electrodes, thereby depositing a continuous coating upon said electrode, the improvement which comprises employing as the electrode to be coated an electrically conductive surface having an adherent coating of a primer comprising an open cell containing, water permeable, continuous film of an inherently non-conductive organic polymeric material, said film being capable of passing an electric current when in contact with an aqueous electrolyte, said primer coating having been formed by a. applying to said electrically conductive surface a composition comprising (1) a thermosetting resin and (2) a solvent-extractable thermoplastic resin, which resin are at least partially compatible and curing the thermosetting resin, thereby forming discrete particles of the thermoplastic resin in the thermoset resin matrix b. solvent extracting the thermoplastic polymer to provide said adherent primer coating comprising an open cell containing, water permeable, continuous film.

Claim 3

A method as in claim 3 wherein the primer coating contains at least about 10 percent void volume.

Claim 4

In a method of electrocoating comprising coating an electrode in electrical contact with a counter-electrode and an aqueous medium comprising an ionically solubilized synthetic organic resin by passing an electric current between the electrodes, thereby depositing a continuous coating upon said electrode, the improvement which comprises employing as the electrode to be coated an electrically conductive surface having an adherent coating of a primer comprising an open cell containing, water permeable, continuous film of an inherently non-conductive organic polymeric material, said film being capable of passing an electric current when in contact with an aqueous electrolyte, said primer coating having been formed by a. applying to said electrically conductive surface a composition comprising an aqueous disperSion of a polymer containing, based on the weight of the dispersion, from 10 to 50 percent of a water soluble organic solvent for the polymer, the solvent boiling above 100*C and being present in a concentration that is insufficient to dissolve the polymer b. removing a substantial amount of aqueous media by evaporation until the partial coalesence of the polymer occurs c. washing the resultant film with water to produce a coherent solvent free film d. drying the film at a temperature below the softening point of the film to provide said adherent primer coating comprising an open cell containing water permeable, continuous film.

Claim 5

In a method of electrocoating comprising coating an electrode in electrical contact with a counter-electrode and an aqueous medium comprising an ionically solubilized synthetic organic resin by passing an electric current between the electrodes, thereby depositing a continuous coating upon said electrode, the improvement which comprises employing as the electrode to be coated an electrically conductive surface having an adherent coating of a primer comprising an open cell containing, water permeable, continuous film of an inherently non-conductive organic polymeric material, said film being capable of passing an electric current when in contact with an aqueous electrolyte, said primer coating having been formed by a. applying to said electrically conductive surface a dispersion of a finely divided thermoplastic powder throughout a highly viscous inert incompatible medium maintained as a continuous phase b. fusing the thermoplastic particles c. leaching out the inert material without affecting the fused thermoplastic particles to provide said adherent primer coating comprising an open cell containing, water, permeable, continuous film.

Claim 6

In a method of electrocoating comprising coating an electrode in electrical contact with a counter-electrode an aqueous medium comprising an ionically solubilized synthetic organic resin by passing an electric current between the electrodes, thereby depositing a continuous coating upon said electrode, the improvement which comprises employing as the electrode to be coated an electrically conductive surface having an adherent coating of a primer comprising an open cell containing, water permeable, continuous film of an inherently non-conductive organic polymeric material, said film being capable of passing an electric current when in contact with an aqueous electrolyte, said primer coating having been formed by a. applying to said electrically conductive surface a layer of a solution of a polymer in an organic solvent b. bathing the layer with a mixture of an organic solvent for the polymer and a non-solvent for the polymer that is at least partially miscible with said solvent until the layer is coagulated into a cellular structure of interconnecting microvoids c. removing substantially all the solvent from the layer d. removing substantially all the non-solvent from the resulting substantially solvent-free microporous layer to provide said adherent primer coating comprising an open cell containing, water permeable, continuous film.

Claim 7

In a method of electrocoating comprising coating an electrode in electrical contact with a counter-electrode and an aqueous medium comprising an ionically solubilized synthetic organic resin by passing an electric current between the electrodes thereby depositing a continuous coating upon said electrode, the improvement which comprises employing as the electrode to be coated an electrically conductive surface having an adherent coating of a primer comprising an open cell containing, water permeable, continuous film of an inherently non-conductive organic polymeric material, said film being capable of passing an electric current when in contact with an aqueous electrolyte, said primer coating having been formed by a. applying to said electrically conductive surface a coating composition comprIsing a film forming polymer and a non-solvent for said polymer, said non-solvent being of lower volatility than other liquids present in said coating composition, the amount of non-solvent present in the coating composition being sufficient to produce upon removal an open interconnected cell containing film having a Kubelka-Munk scatting coefficient greater than 0.5 reciprical mil at 4400 Angstroms and greater than 0.1 reciprocal mil at 5600 greater than 0.1 reciprocal mil at 5600 Angstroms and less than that which upon removal produces a disparticulate film b. forming a continuous polymer film containing said non-solvent c. removing said non-solvent to provide said adherent primer coating comprising an open cell containing, water permeable, continuous film.

Claim 8

A method as in claim 8 wherein the primer coating contains at least about 10 percent void volume.