Solution or Suspension Containing Fluoropolymer, Method for Producing Same, and Use Thereof for Producing Piezoelectric and Pyroelectric Coatings

A method for the manufacture of a suspension of inorganic particles of a piezoelectrically and pyroelectrically active or activatable oxide in a homogeneous solution of a fluoropolymer, selected among fluoro-homopolymers and copolymers and mixtures of different fluoro-homopolymers and/or copolymers, in a high boiling point solvent, comprising the steps:

• (a) manufacture of a suspension of the inorganic particles in a suspending agent,
• (b) dissolution of the fluoropolymer in a mixture comprising at least two solvents, the first of which has a boiling point below 150° C., and/or a vapor pressure above 5 hPa (at 20° C.) and the second of which is a high boiling point solvent having a boiling point that is at least 50° K higher than the one of the first solvent and/or the boiling point of which is selected such that the solvent mixture has a separation factor α of ≧1,
• (c) addition of the suspension of the inorganic particles to the solution of the fluoropolymer according to (b) and
• (d) complete or almost complete removal of the first solvent and the suspending agent.

A method for the manufacture of a suspension of inorganic particles of a piezoelectrically and pyroelectrically active or activatable oxide in a homogeneous solution of a fluoropolymer, selected among fluoro-homopolymers and copolymers and mixtures of different fluoro-homopolymers and/or copolymers, in a high boiling point solvent, comprising the steps:

• (a) manufacture of a suspension of the inorganic particles in a suspending agent,
• (b) manufacture of a fluoropolymer solution, wherein
• (1) the fluoropolymer to be dissolved is dissolved in a mixture comprising at least two solvents, the first of which has a boiling point below 150° C., and/or a vapor pressure above 5 hPa (at 20° C.) and the second of which is a high boiling point solvent having a boiling point that is at least 50° K higher than the one of the first solvent and/or the boiling point of which is selected such that the solvent mixture has a separation factor α of ≧1, and
• (2) almost all or all of the first solvent is subsequently removed from the mixture,
• (c) addition of the suspension of the inorganic particles to the solution of the fluoropolymer according to (b) and
• (d) complete or almost complete removal of the suspending agent.