Process for coating fine powders with a nylon and products made therewith
AssigneeRilsan Corporation
InventorRobert B. Koch
Life of this patent
Estimating the term…
Abstract
A method for coating powders with nylon by mixing the powder with the nylon and a solvent for the nylon, precipitating the nylon out of solution and coating the powder particles, and separating the coated powder substantially in the form of agglomerates of individually coated particles. The coated powder can then be readily compressed to form a shaped structure, such as, a molded article. A nylon coated powder especially suitable for conversion into shaped structures by melt processes, such as, injection molding or melt extrusion, is obtained by incorporating an organic polymer modifier into the nylon coated powder.
Claims25
A method of making a shaped structure composed of a nylon binder and a material in particle form, substantially each individual particle of the material being surrounded by the binder to form a coated powder, the shaped structure having substantially no particle to particle contact and having distribution of the nylon binder substantially uniform throughout, comprising:
- A. charging into a forming apparatus the coated powder of the material particles coated with the nylon, the nylon being one which adheres to the individual material particles and is capable of being drawn into a filament or fiber and being a polyamide wherein the recurring amide groups are separated from each other by an alkylene radical having from 3 to 12 contiguous carbon atoms,
- 1. the coated powder being substantially in the form of agglomerates of individually coated particles of the material,
- 2. the coated powder comprising individual particles of the material having a size from about 1 millimicron to about 500 microns and having a substantially uniform coating of nylon, the material particles being insoluble in solvents which dissolve the nylon, the nylon coating representing at least 2% based on the weight of the coated powder;
- B. compressing the coated powder in the forming apparatus at a pressure of about 200 - 100,000 psi to bind and form the coated particles into the shaped structure;
- and
- C. recovering the shaped structure from the forming apparatus.
A method of making a shaped structure composed of a nylon copolymer binder, a material in particle form, and an organic polymer modifier, substantially each individual particle of the material being surrounded by the nylon copolymer binder to form a coated powder, the shaped structure having substantially no particle to particle contact and having distribution of the nylon copolymer binder substantially uniform throughout, comprising:
- A. charging into a forming apparatus the coated powder with the organic polymer modifier to form a modified coated powder, the nylon copolymer being one which adheres to the material particles and being a polyamide of the type which is capable of being drawn into a filament or fiber and in which the recurring amide groups are separated from each other by an alkylene radical having from 3 to 12 contiguous carbon atoms;
- 1. the modified coated powder being substantially in the form of agglomerates of individually coated particles of said material,
- 2. the coated powder comprising individual particles of the material having a size from about 1 millimicron to about 500 microns and having a substantially uniform coating of the nylon copolymer, the material particles being insoluble in solvents which dissolve the nylon copolymer, the nylon copolymer coating representing at least 2% based on the weight of the modified coated powder,
- B. compressing the modified coated powder in the forming apparatus at a pressure of about 200 - 100,000 psi at a temperature of about 32.degree. to about 50.degree. F below the thermal degradation temperature of the nylon copolymer and of the organic polymer modifier to bind and form the coated particles into the shaped structure;
- and
- C. recovering the shaped structure from the forming apparatus.
Dependencies are inferred from the claim text.