Method for coating discrete particles

Claim 2

A CONTINUOUS METHOD FOR COATING DISCRETE PARTICLES WHICH COMPRISES, IN COMBINATION: CONTINUOUSLY ADVANCING A MASS OF DISCRETE PARTICLES TO BE COATED ALONG A FEED PATH; APPLYING AN AMINO TYPE COUPLING AGENT TO THE PARTICLES AT A FIRST PREDETERMINED POINT ALONG THE FEED PATH TO PROVIDE AN UNCURED COATING ON THE SURFACE OF EACH PARTICLE; INITIATING THE CURING OF THE COUPLING AGENT COATING BY THE APPLICATION OF HEAT THERETO AS THE PARTICLED CONTINUE THEIR MOVEMENT ALONG THE FEED PATH; ADDING AN ANTI-CAKING AGENT TO THE COATED PARTICLES AT A SECOND PREDETERMINED POINT ALONG THE FEED PATH; AND COMPLETING THE CURING OF THE COUPLING AGENT COATING BY CONTINUING THE APPLICATION OF HEAT THERETO AS THE PARTICLES

Claim 3

A method as defined in claim 1, in which the particles are coated with a gamma-aminopropyltriethoxy silane coupling agent.

Claim 4

A method as defined in claim 1, which further comprises: increasing the depth of the mass of coated particles as they advance along said portion of the feed path.

Claim 5

A method as defined in claim 1, in which the particles are advanced along the feed path at a uniform rate of between 1,000 and 5,000 pounds per hour.

Claim 6

A method as defined in claim 1, in which the temperature of the particles at said second predetermined point lies within the range of from about 60* F. to about 160* F.

Claim 7

A continuous method for coating glass spheres which comprises, in combination: continuously advancing a mass of glass spheres to be coated along a feed path; applying a silane coupling agent to the spheres at a first predetermined point along the feed path to provide an uncured coating on the surface of each sphere; initiating the curing of the coupling agent coating by the application of heat thereto as the spheres continue their movement along the feed path; adding an anti-caking agent to the coated spheres at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; and completing the curing of the coupling agent coating by continuing the application of heat thereto as the spheres move along the feed path downstream of said second predetermined point.

Claim 8

A continuous method for coating glass spheres which comprises, in combination: continuously advancing a mass of glass spheres to be coated along a feed path; applying a silane coupling agent to the spheres at a first predetermined point along the feed path to provide an uncured coating on the surface of each sphere; initiating the curing of the coupling agent coating by the application of heat thereto as the spheres continue their movement along the feed path; adding an anti-caking agent to the coated spheres at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; and completing the curing of the coupling agent coating by continuing the application of heat thereto as the spheres move along the feed path downstream of said second predetermined point.

Claim 9

A method as defined in claim 6, in which the coupling agent comprises gamma-aminopropyltriethoxy silane.

Claim 10

A continuous method for coating discrete particles which comprises, in combination: continuously advancing a mass of discrete particles to be coated along a feed path; applying a silane coupling agent to the particles at a first predetermined point along the feed path to provide an uncured coating on the surface of each particle, the thickness of the coupling agent coating on each particle being at least about one molecular layer and not more than about five molecular layers; initiating the curing of the coupling agent coating by the application of heat thereto as the particles continue their movement along the fEed path; adding an anti-caking agent to the coated particles at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; completing the curing of the coupling agent coating by continuing the application of heat thereto as the particles move along the feed path downstream of said second predetermined point; and thereafter discharging the coated particles at a subsequent predetermined point along the feed path, the heat applied to the particles as they move along said path producing a particle temperature at the point of discharge which lies within the range of from about 60 F. to about 160 F.

Claim 11

A continuous method for coating discrete particles which comprises, in combination: continuously advancing a mass of discrete particles to be coated along a feed path; applying a silane coupling agent to the particles at a first predetermined point along the feed path to provide an uncured coating on the surface of each particle, the thickness of the coupling agent coating on each particle being at least about one molecular layer and not more than about five molecular layers; initiating the curing of the coupling agent coating by the application of heat thereto as the particles continue their movement along the fEed path; adding an anti-caking agent to the coated particles at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; completing the curing of the coupling agent coating by continuing the application of heat thereto as the particles move along the feed path downstream of said second predetermined point; and thereafter discharging the coated particles at a subsequent predetermined point along the feed path, the heat applied to the particles as they move along said path producing a particle temperature at the point of discharge which lies within the range of from about 60 F. to about 160 F.

Claim 12

A continuous method for coating glass spheres which comprises, in combination: continuously advancing a mass of glass spheres to be coated along a feed path; applying a gamma-aminopropyltriethoxy silane coupling agent directly to the surfaces of the spheres at a first predetermined point along the feed path to provide an uncured coating on the surface of each sphere; initiating the curing of the coupling agent coating by the application of heat thereto as the spheres continue their movement along the feed path; increasing the depth of the mass of coated spheres as they advance along a portion of the feed path; agitating the mass of coated spheres as it moves along said path portion at said increased depth; adding an anti-caking agent to the coated spheres at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; continuing the agitation of the mass of coated spheres during the addition of the anti-caking agent to provide a uniform anti-caking coating on each sphere around the coupling agent coating; and completing the curing of the coupling agent coating by continuing the application of heat thereto as the spheres move along the feed path downstream of said second predetermined point.

Claim 13

A continuous method for coating glass spheres which comprises, in combination: continuously advancing a mass of glass spheres to be coated along a feed path; applying a gamma-aminopropyltriethoxy silane coupling agent directly to the surfaces of the spheres at a first predetermined point along the feed path to provide an uncured coating on the surface of each sphere; initiating the curing of the coupling agent coating by the application of heat thereto as the spheres continue their movement along the feed path; increasing the depth of the mass of coated spheres as they advance along a portion of the feed path; agitating the mass of coated spheres as it moves along said path portion at said increased depth; adding an anti-caking agent to the coated spheres at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; continuing the agitation of the mass of coated spheres during the addition of the anti-caking agent to provide a uniform anti-caking coating on each sphere around the coupling agent coating; and completing the curing of the coupling agent coating by continuing the application of heat thereto as the spheres move along the feed path downstream of said second predetermined point.

Claim 14

A method as defined in claim 9, in which the amount by weight of anti-caking agent added to the spheres is between about 1/2 and about 1 1/2 percent of the weight of the spheres.

Claim 15

A continuous method for coating discrete particles which comprises, in combination: continuously advancing a mass of discrete particles to be coated along a feed path at a rate of between one thousand and five thousand pounds per hour; applying a silane coupling agent directly to the surfaces of the particles at a first predetermined point along the feed path to provide an uncured coating on the surface of each particle, the thickness of the coupling agent on each particle being at least one molecular layer and not more than five molecular layers; initiating the curing of the coupling agent coating by the application of heat thereto as the particles continue their movement along the feed path; increasing the depth of the mass of coated particles as they advance along a portion of the feed path; agitating the particle mass as the coated particles move along said path portion at said increased depth; adding an anti-caking agent to the coated particles at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; continuing the agitation of coated the mass of particles during the addition of the anti-caking agent to provide a uniform anti-caking coating on each particle around the coupling agent coating; completing the curing of the coupling agent coating by continuing the application of heat thereto as the particles move along the feed path downstream of said second predetermined point; and thereafter discharging the coated particles at a subsequent predetermined point along the feed path, the heat applied to the particles as they move along said path producing a particle temperature at the point of discharge which lies within the range of from about 60* F. to about 160* F.

Claim 16

A continuous method for coating discrete particles which comprises, in combination: continuously advancing a mass of discrete particles to be coated along a feed path at a rate of between one thousand and five thousand pounds per hour; applying a silane coupling agent directly to the surfaces of the particles at a first predetermined point along the feed path to provide an uncured coating on the surface of each particle, the thickness of the coupling agent on each particle being at least one molecular layer and not more than five molecular layers; initiating the curing of the coupling agent coating by the application of heat thereto as the particles continue their movement along the feed path; increasing the depth of the mass of coated particles as they advance along a portion of the feed path; agitating the particle mass as the coated particles move along said path portion at said increased depth; adding an anti-caking agent to the coated particles at a second predetermined point along the feed path, the anti-caking agent comprising an amine salt of a hydrophillic colloid; continuing the agitation of coated the mass of particles during the addition of the anti-caking agent to provide a uniform anti-caking coating on each particle around the coupling agent coating; completing the curing of the coupling agent coating by continuing the application of heat thereto as the particles move along the feed path downstream of said second predetermined point; and thereafter discharging the coated particles at a subsequent predetermined point along the feed path, the heat applied to the particles as they move along said path producing a particle temperature at the point of discharge which lies within the range of from about 60* F. to about 160* F.