Coating of particles and process for manufacturing said coating

Abstract

Abstract A PROCESS IS DISCLOSED FOR COATING SMALL PARTICLES ONTO A SUBSTRATE SURFACE WHEREIN THE PARTICLES INITIALLY HAVE A COVERING OF HEAT SOFTENABLE MATERIAL. THE PARTICLES ARE COATED ONTO THE SUBSTRATE BY BEING CONTACTED WITH THE SUBSTRATE WHILE IT IS AT A TEMPERATURE ABOVE THAT REQUIRED TO CAUSE THE HEAT SOFTENABLE MATERIAL TO BECOME FLOWABLE. THE COVERING ON THE PARTICLES THEN FLOWS TO POINTS OF CONTACT BETWEEN THE PARTICLES AND THE SUBSTRATE AND BETWEEN INDIVIDUAL PARTICLES THEMSELVES. THE SUBSTRATE IS COOLED TO A TEMPERATURE AT WHICH THE ONCESOFTENED MATERIAL IS SOLID AND, PERHAPS ALSO CROSS-LINKED, THEREBY PROVIDING AN ADHESIVE BINDING BETWEEN THE PAR- TICLES AND OBJECTS TOUCHING THE PARTICLES. THE THUS-MANUFACTURED PARTICLE-COATED SUBSTRATE IS ALSO CONSIDERED TO BE A PART OF THE PRESENT INVENTION. IN A PREFERRED EMBODIMENT OF THE PRESENT INVENTION, THE PARTICLES ARE MINUTE, SUBSTANTIALLY SPHERICAL, CAPSULES HAVING CAPSULE WALLS OF AS POLYMERIC FILM-FORMING MATERIAL, AND CONTAINING A CAPSULE INTERNAL PHASE. IN THAT PREFERRED EMBODIMENT, THE HEAT SOFTENABLE MATERIAL WHICH COVERS THE MINUTE CAPSULES IS PRESENT, AS A COVERING, IN THE FORM OF VERY FINELY-DIVIDED DUST CLINGINGLY ADHEREST TO THE CAPSULE WALLS AND IS THERMOSETTING AFTER BEING, INITIALLY, HEAT-SOFTENED.

Inventors

• 👤 Hugh W Campbell

Bibliographic Details