Claims
- 1. In a method of providing a substrate with a self-adherent coating of a high molecular weight, linear polyamide wherein
- (1) the substrate is coated with a dispersion comprising water, finely-divided, water dispersible, low molecular weight, linear polyamide resin particles, between about 0.15% and about 0.8%, based upon the weight of the resin, of a catalyst consisting of a non-volatile, strong acid or a compound which upon heating is converted to a non-volatile, strong acid and between about 1% and 8%, based upon the weight of the resin, of a flow promoter,
- (2) the coated substrate is heated to at least the melting temperature of the polyamide resin and
- (3) the heated substrate is maintained at the temperature for a period sufficient to cause the polyamide resin to flow and to polymerize the resin to a predetermined high molecular weight,
- the improvement which comprises employing as the dispersed polyamide resin particles, finely-divided, water dispersible, low molecular weight, linear polyamide resin particles consisting of loosely packed, randomly oriented, clusters of flaky sheets, the mean particle size of the dispersed particles being between about 0.03 micron and about 6 microns and the particle size distribution being about d + 0.8 d, where d is the mean particle size.
- 2. The method as defined in claim 1 wherein the low molecular weight polyamide resin has a reduced viscosity betwween about 0.15 and about 0.26 and the coated substrate is heated to a temperature between 205.degree. C. and 240.degree. C. for from 5 minutes to 15 minutes.
- 3. The method as defined in claim 2 wherein the substrate is a metal.
- 4. The method as defined in claim 2 wherein the substrate is glass.
- 5. In a method of providing a substrate with a self-adherent coating of a high molecular weight, linear polyamide wherein
- (1) there is provided a fluidized bed of powder consisting essentially of low molecular weight, linear polyamide resin particles, between about 0.15% and about 0.8%, based upon the weight of the polyamide resin, of a catalyst consisting of a non-volatile, strong acid or a compound which upon heating is converted to a non-volatile, strong acid and between about 1% and 8%, based upon the weight of the polyamide resin, of a flow promoter,
- (2) a heated substrate at a temperature of at least the melting temperature of the polyamide resin is immersed into the fluidized bed and
- (3) the heated substrate is maintained at the temperature for a period sufficient to cause the resin in contact with the substrate to flow and to polymerize to a predetermined high molecular weight,
- the improvement comprises employing as the low molecular weight, linear polyamide resin particles, particles consisting essentially of loosely bound agglomerates of loosely packed, randomly oriented clusters of flaky sheets.
- 6. The method as defined in claim 5 wherein the low molecular weight polyamide resin has a reduced viscosity between about 0.15 and about 0.26 and the substrate is heated to a temperature between 205.degree. C. and 240.degree. C. for from 5 minutes to 15 minutes.
- 7. The method as defined in claim 6 wherein the substrate is a metal.
- 8. The method as defined in claim 6 wherein the substrate is glass.
Parent Case Info
This application is a division of application Ser. No. 492,609, filed July 29, 1974 (abandoned in view of continuation application Ser. No. 681,852, filed Apr. 30, 1976), which is a division of application Ser. No. 248,063, filed Apr. 27, 1972, now U.S. Pat. No. 3,844,991, dated Oct. 29, 1974.
US Referenced Citations (11)
Foreign Referenced Citations (1)
Number |
Date |
Country |
1,180,023 |
Feb 1970 |
UK |
Divisions (2)
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Number |
Date |
Country |
Parent |
492609 |
Jul 1974 |
|
Parent |
248063 |
Apr 1972 |
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