Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Rapid drying of fluoropolymer dispersion coating compositions

A technology of polymer and composition, applied in the direction of coating, layered products, thin material processing, etc., can solve the problems of unfavorable overall productivity, increased drying time, influence and other problems of fluoropolymer coating processing

Inactive Publication Date: 2009-03-25
EI DU PONT DE NEMOURS & CO
View PDF5 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, when the fluorosurfactant content of the dispersion was reduced using methods such as disclosed in US6833403 to Bladel et al., a significant increase in drying time in microwave drying operations was observed
In processes where drying is the rate limiting step, the overall productivity of fluoropolymer coating processing will be adversely affected

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0084] A 1% by weight stock solution of ammonium sulfate and ammonium fluoride was prepared by dissolving 1 g of the aforementioned salts in 99 g of deionized water. An aliquot of the salt stock solution was added to a 100 g sample of the PTFE dispersion prepared above. An aliquot was added to the PTFE dispersion sample in such a way that the conductivity of the PTFE dispersion sample increased to the target level. The result is as follows

[0085] Table 1 Reference sample and conductivity of PTFE dispersion containing ammonium sulfate

[0086] Dispersion solution 1% ammonium sulfate solution addition amount Conductivity S200 * 0.0g 196μS S250 0.5g 268μS S500 2.0g 494μS S750 4.0g 757μS S1000 6.0g 1029μS S1250 7.0g 1250μS

[0087] * Reference sample - no salt added

[0088] Table 2 Conductivity of PTFE dispersions containing ammonium fluoride

[0089] Dispersion solution 1% ammonium sulfate solution a...

Embodiment 2

[0097] PTFE-coated pump gasket material is made of ~1 / 2 inch (1 cm) diameter Manufactured from braided wire made of aramid fibers. The fibrous matrix was passed as individual braided strands through a reduced APFO PTFE dispersion bath prepared as described above (~60 wt% solids, 6 wt% TMN-10 nonionic surfactant, APFO content is less than 20ppm). Ammonium sulfate was added to the dispersion in the bath in an amount sufficient to raise the conductivity to about 1080 μS.

[0098] After the coating step, the substrate wire with the wet coating of the dispersion containing the added ammonium sulfate was passed through a microwave oven to remove water and surfactant. In addition, a PTFE dispersion (conductivity <250 μS) with no added water soluble salt was used to provide a wet coating on the same wire to provide a microwave dried comparison. Higher conductivity PTFE dispersions (~1080 μS) surprisingly reduced the time required for microwave drying compared to PTFE dispersions...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
particle sizeaaaaaaaaaa
wavelengthaaaaaaaaaa
particle sizeaaaaaaaaaa
Login to View More

Abstract

A process for making a fluoropolymer coated substrate comprising: applying an aqueous fluoropolymer dispersion coating composition comprising an aqueous medium and fluoropolymer particles with a fluorosurfactant content of less than about 300 ppm to a substrate to form a wet coating on the substrate, the aqueous fluoropolymer coating composition comprising added water soluble salt; and drying the wet coating to form the fluoropolymer coated substrate by applying high frequency electromagnetic radiation to the wet coating, the added water soluble salt being effective to decrease the time required to dry the wet coating on the substrate by at least about 5% compared to an otherwise identical coating composition without the added water soluble salt.

Description

field of invention [0001] This invention relates to aqueous fluoropolymer dispersion coating compositions and methods of forming coatings from the dispersions. Background of the invention [0002] Fluoropolymers are used on a wide variety of substrates to impart anti-stick properties, chemical and heat resistance, corrosion protection, cleanability, low flammability and weather resistance. Coatings of polytetrafluoroethylene (PTFE) homopolymer and modified PTFE have the highest thermal stability among fluoropolymers, but unlike tetrafluoroethylene (TFE) copolymers, cannot be melt processed to form thin films and coating. Therefore other methods have been developed to apply coatings of PTFE homopolymer and modified PTFE. One such method is dispersion coating, which uses fluoropolymers in dispersion form, and although primarily used to apply PTFE coatings, melt-processable TFE copolymers are also used in some applications. Dispersion coatings. Dispersion coating methods ty...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C03C25/30C09D127/12
CPCY10T428/2991Y10T428/3154C09D127/18Y10T428/25B32B17/04Y10T428/2982C03C25/1095
Inventor J·T·恩格利什D·弗劳尔斯R·G·赫克
Owner EI DU PONT DE NEMOURS & CO
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com