Abstract: The present invention relates to a property determining apparatus for automatically determining in real time, properties of a slurry material such as of a sludge under treatment. The apparatus, being provided with a sampling cylinder 2, a quantitative sampling piston pair comprised of a rear piston 3 and a front piston 4, an air cylinder 5, a measurement tank 8, and a measuring means 10, is connected to a transfer pipe P and the like for a slurry material via a connecting opening 2w of the sampling cylinder 2.

Abstract: A sampling cylinder 3 is attached to a process piping 2 through which a slurry flows. A front piston 9 and a rear piston 10 which slide within the sampling cylinder 3 are driven via a driving rod 12 by a fluid pressure cylinder 11. These two pistons 9,10 are allowed to slide to collect the slurry into a sampling space 30 defined between the pistons 9,10. The front piston 9 is brought closer to the rear piston 10 to reduce the volume of the sampling space 30. Thus, only the filtrate in the slurry is fed through a filter 5 into a filtrate collecting tank 6, where pH etc. of the filtrate is measured by a sensor 8. Subsequently, the front piston 9 is brought apart from the rear piston 10 to increase the volume of the sampling space 30. Thus, the filtrate is returned into the sampling space 30 back-washing the filter 5. Then, the slurry in the sampling space 30 is returned to the process piping 2.

Abstract: Colloidal polytetrafluoroethylene fine particles having an average particle size of 0.05 to 1.0 .mu.m and each comprising a core made of polytetrafluoroethylene which has a high molecular weight and can be fibrilled and a shell surrounding the core and made of a low molecular weight polytetrafluoroethylene which is not fibrilled, which has good dispersibility in water or an organic solvent and easily provides an organosol by a phase transfer method.

Abstract: Modified PTFE fine powder which comprises colloidal particles of a copolymer comprising repeating units derived from tetrafluoroethylene and 0.02 to 0.3 % by weight, preferably 0.03 to 0.2% by weight of repeating units derived from at least one fluoroalkyl vinyl ether selected from compounds of the formula:X(CF.sub.2).sub.n OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen, fluorine or chlorine atom and n is an integer of 1 to 6, andC.sub.3 F.sub.7 (OCF.sub.2 CF.sub.2 CF.sub.2).sub.m [OCF(CF.sub.3)CF.sub.2 ].sub.1 OCF.dbd.CF.sub.2 (II)wherein m and 1 are each an integer of 0 to 4 provided that at least one of them is not zero, which has a number average particle size of 0.05 to 0.6 .mu.m, wherein the copolymer has a specific melt viscosity of from 6.times.10.sup.10 to 30.times.10.sup.10 poise, preferably from 8.0.times.10.sup.10 to 25.times.10.sup.10 poise at 380.degree. C. and a standard specific gravity (SSG, hereinafter defined) of from 2.135 to 2.175, preferably from 2.140 to 2.

Abstract: Modified PTFE fine powder which comprises colloidal particles of a copolymer comprising repeating units derived from tetrafluoroethylene and 0.02 to 0.3% by weight, preferably 0.03 to 0.2% by weight of repeating units derived from at least one fluoroalkyl vinyl ether selected from compounds of the formula:X(CF.sub.2).sub.n OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen, fluorine or chlorine atom and n is an integer of 1 to 6, andC.sub.3 F.sub.7 (OCF.sub.2 CF.sub.2 CF.sub.2).sub.m [OCF(CF.sub.3)CF.sub.2 ].sub.l OCF.dbd.CF.sub.2 (II)wherein m and l are each an integer of 0 to 4 provided that at least one of them is not zero, which has a number average particle size of 0.05 to 0.6 .mu.m, wherein the copolymer has a specific melt viscosity of from 6.times.10.sup.10 to 30.times.10.sup.10 poise, preferably from 8.0.times.10.sup.10 to 25.times.10.sup.10 poise at 380.degree. C. and a standard specific gravity (SSG, hereinafter defined) of from 2.135 to 2.175, preferably from 2.140 to 2.

Abstract: A polytetrafluoroethylene porous film obtainable by applying an aqueous dispersion of emulsion polymerized polytetrafluoroethylene particles having an average minor particle size of 1 to 500 nm and an average aspect ratio of at least 10 on a substrate, drying the applied dispersion and optionally sintering the dried polytetrafluoroethylene particles on the substrate to obtain the polytetrafluoroethylene porous film, which has a uniform thin thickness.

Abstract: Polytetrafluoroethylene powder having an average particle size of 1 to 30 .mu.m and a specific surface area of 2 to 6 m.sup.2 /g is prepared by heating unsintered polytetrafluoroethylene powder having a melting point of 313.degree. to 330.degree. C. at a temperature in a range from a temperature 70.degree. C. lower than the melting point to a temperature lower than the melting point and comminuting the heated powder.

Abstract: Modified PTFE fine powder which comprises primary particles having an average particle size of 0.1 to 0.6 .mu.m and contains 0.01 to 0.15% by weight, based on the total weight of the particles, of at least one olefinically unsaturated compound selected from the group consisting of a fluoroalkyl vinyl ether of the formula:X(CF.sub.2).sub.n OCF.dbd.CF.sub.2 (I)wherein X is a hydrogen atom, a fluorine atom or a chlorine atom and n is an integer of 1 to 6, and a fluoroalkyl vinyl ether of the formula:C.sub.3 F.sub.7 (OCF.sub.2 CF.sub.2 CF.sub.2).sub.m [OCF(CF.sub.3)CF.sub.2 ].sub.l OCF.dbd.CF.sub.2 (II)wherein m is an integer of 0 to 2 and l is an integer of 0 to 2 mainly in core parts of the particles and 0.04 to 0.25% by weight, based on the total weight of the particles, of chlorotrifluoroethylene in shell parts, which has good paste extrudability and heat stability.

Abstract: A fluoroelastomer composition comprising a fluoroelastomer and a thermoplastic fluoroelastomer, which has good roll retention and roll processability and a mixed compound of which has little self-adhesiveness.

Abstract: An apparatus for accurately measuring the freeness of paper stock in a short time is disclosed.The apparatus comprises a pump and plunger which take a sample of stock from a flowline or a place in which paper stock is prepared and places the sample in an agitation tank. A water supply dilutes the sample in the agitation tank to a predetermined consistency and a first pressurized air supply agitates the diluted sample so that fibrous material in the stock is evenly dispersed in the water. The agitation tank is closed to the atmosphere and a second pressurized air supply provides a pressure in the tank for draining the liquid from the sample through a screen. The liquid which passes through the screen is delivered to a measuring cylinder.