Micropowder

Micropowders are added to a wide variety of material used in industry, where they provide nonstick and sliding properties. They are incorporated into the product by blending and grinding. To disperse weU, the powder must have good flow properties. Conditions that make the powder sticky should be avoided. 

The PTFE micropowders are commonly used in plastics, inks, lubricants, and finishes such as lacquer. Lubricants containing micropowders are used for bearings, valve components, and other moving parts where sliding friction must be minimized or eliminated. Nonstick finishes that require good release properties, for example, in the food and packaging industry, commonly use PTFE micropowders. 

In some appHcations the high heat stabiHty of the micropowder can be utilized over a reasonably wide temperature range. A maximum service temperature is normally 260°C, provided the crystalline melting point is between 320 and 335°C. Exposure above 300°C leads to degradation and possible evolution of toxic decomposition products. 

Bean, C.P. (1955) Hysteresis loops of mixtures of ferromagnetic micropowders. Journal of Applied Physics, 26 (11), 1381-1383. 

PTFE films, 18 334 PTFE micropowders, 18 306 PTG black and white developers, 19 346-347... 

Spray pyrolysis routes have been extensively investigated to prepare Pt-based catalysts. Typically, a liquid feed of metal precursor and carbon is atomized into an aerosol and fed into a continuous furnace to evaporate and heat-treat to form a collectable powder. The method has good control over final aggregate particle size and metal particle size distributions, as well as producing powder without further isolation or separation. Hampton-Smith et al. have reviewed efforts of Superior MicroPowder (now Cabot Fuel Cells) in this area. ... 

Polytetrafluoroethylene Degradation into low-molecular-weight products ("micropowders") used as additives to coatings, lubricants, and inks High-energy irradiation at 200-400 kGy... 

NBR containing irradiated PTFE micropowder for high performance tribological applications [23]. 

Minch s method is designed for determination of the abrasive power of powders and polishing micropowders, grain-size 160-3 (am. The test outfit miniaturized when compared to Bohme s disc, shows an average of three times lower wear of the glass plate for the same abrasive action time and the same grain size (A. Szymanski, 1972). 

Superior MicroPowders Cabot Superior MicroPowders Carbon Black AP Materials, Inc. 

Sunways Production GmbH SUNWAYS AG Superior MicroPowders CABOT CORPORATION Supreme Biotane IMPERIAL WESTERN PRODUCTS INC... 

Micropowders, PTFE homopolymers with molecular weight significantly lower than normal PTFE, are commonly used as additives in a large number of applications where they provide nonstick and sliding properties. They are added to plastics, inks lubricants, and lacquers.14... 

PTFE is attacked by irradiation by y-rays, high-energy electron beams, or X rays. The degradation of the polymer in air or oxygen occurs due to scission of the chain and is fairly rapid. Such scission results in molecular weight reduction.20 When irradiated by an electron beam, the molecular weight is reduced up to six orders of magnitude to produce micropowders.21... 

Microabrasion using compressed air is a modification based on sandblasting, the micropowder blasting. This process enables all types of glass, ceramics and semiconductor materials, irrespective of their chemical composition and crystal structure, to be inexpensively processed down to the micrometer scale. The micropowder blasting is a masked procedure and works quasi-parallel on the whole substrate. A powder jet drives systematically over the substrate. Material is removed at the mask openings (see Figure 2.17). 

ETFE, FEP, PFA, FEVE, PVDE, fluorocarbon elastomers (TFE/P), PTEE, amorphous PTFE, PTFE micropowders Fluorocarbon TPE... 

EFEP, ETFE, FEP, PCTFE, PEA, PTEE, PTFE micropowders, fluorocarbon elastomers (FKM, fluorinated TPE), FKM latex Fluorosilicones... 

ETFE, FEP, HTE fluoroplastic, THV fluoroplastic, PTFE, modified PTFE, PTFE micropowders, PFA, PVDF, fluorocarbon elastomers (FKM, FFKM) PCTFE... 

The largest proportion of TEE is used for the polymerization into a variety of PTFE homopolymers, modihed PTFE, and micropowders. It is also used as comonomer in the copolymerization with hexafluoropropylene, ethylene, perfluorinated ether, and other monomers and also as a comonomer in a variety of terpolymers. Other uses of TEE are to prepare low-molecular-weight polyfluorocarbons and carbonyl fluoride oils as well as to form PTFE in situ on metal surfaces [14] and in the synthesis of hexafluoropropylene, perfluorinated ethers, and other oligomers [15]. 

PTFE micropowders or fluoroadditives (e.g., Zonyl TE-3887, DuPont) are available in aqueous dispersions with 50% to 60% solids. They have very small particle size, typically in the range of 2 to 20 pm, and contain typically 6% of nonionic wetting agent and stabilizer. Usual pH of these dispersions is 10. PTFE micropowders are used as additives to paints and coatings, for demolding, and for lubrication (for details see Publication L-13812, 01/07, DuPont). 

---