摘要:
Ethylene fluoro-containing copolymers of the ECTFE and ETFE type, optionally in the presence of a third comonomer in amount comprised between 0.1 and 10% by moles, having a viscosity between 102 and 105 Pa.sec with shear rates of 1 sec−1 measured at the temperature of about 30° C. higher than the second melting temperature, and having a rheologic curve in the diagram shear viscosity/shear-rate with a slope higher than 200, calculated as ratio between the viscosity in Pa.sec and the shear-rate in sec−1 in the shear-rate range comprised between 1 and 10 sec−1, and having a processability zone with shear-rate values higher than 10 s−1.
摘要:
Manufactured articles obtainable from a composition consisting of:1) 100 phr of a fluorinated thermoplastic elastomer having a block structure with at least a fluorinated polymeric segment of B type having elastomeric properties and at least a fluorinated polymeric segment of A type having plastomeric properties,2) from 0.1 to 40 phr of a crosslinking agent able to give peroxidic crosslinking of fluoroelastomers;and subsequent irradiation of the manufactured article by GAMMA or BETA radiations.
摘要:
Compounds comprising a peroxide and a peroxide curable blend essentially consisting of hydrocarbon elastomers containing at least an acrylic monomer and of fluorinated VDF-based elastomers having in the polymer chain at least 5% by moles of hydrogenated groups C.sub.1 of the type ##STR1## --CH.sub.2 -- and/or --CH.sub.3, the amount of fluorinated rubber in the elastomeric blend being comprised from 5 to 75% by weight, said elastomers of the blend not containing iodine and/or bromine.
摘要:
New fluoroelastomers are described, having iodine atoms in terminal position and monomeric units in the chain deriving from an iodinated olefin of formula:CHR.dbd.CH--Z--CH.sub.2 CHR--I (I)wherein: R is --H or --CH.sub.3 ; Z is a (per)fluoroalkylene radical C.sub.1 -C.sub.18, linear or branched, optionally containing one or more ether oxygen atoms, or a (per)fluoropolyoxyalkylene radical.These products, upon peroxide curing, require extremely short post-curing treatments (around 30-60 minutes at 180.degree.-230.degree. C.) and are characterized by compression set values lower than 25% (measured on O-rings at 200.degree. C. for 70 hours according to ASTM Standard D395 Method B).
摘要:
Fluorinated thermoplastic elastomers comprising monomeric units deriving from a bis-olefin having general formula: ##STR1## wherein: R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, equal or different from each other, are H or alkyls C.sub.1 -C.sub.5 ; Z is an alkylene or cycloalkylene radical C.sub.1 -C.sub.18, linear or branched, optionally containing oxygen atoms, preferably at least partially fluorinated, or a (per)fluoropolyoxyalkylene radical.
摘要:
Fluorinated thermoplastic elastomers comprising monomeric units deriving from at least an iodinated olefin of formula:CX.sub.2 .dbd.CX--R.sub.f --CHR--I (I)wherein:X is --H, --F, or --CH.sub.3 ; R is --H or --CH.sub.3 ; R.sub.f is a (per) fluoroalkylene radical, linear or branched, optionally containing one or more ether oxygen atoms, or a (per) fluoropolyoxyalkylene radical.
摘要:
A rotating stirring device, particularly for mixing heterogeneous systems in mechanical stirred reactors, is fit to be joined to a drive shaft coaxial with respect to the device rotation axis. The device includes a plurality of extended and substantially C-shaped stirring elements symmetrically arranged with respect to the rotation axis and joined to each other at respective ends corresponding with the rotation axis. Such a device permits a very efficient material exchange among different phases to be obtained and to remain substantially constant with an increase in the volume of the mass being stirred. The device is also characterized by a high mixing homogeneity and particularly low shear stress values.
摘要:
Fluoroelastomeric copolymers, vulcanizable by ionic methods, suitable for the manufacture of "shaft seals" and "fuel hoses", comprising by weight:______________________________________ VDF 30-47% HFP 20-40% PAVE 3-20% TFE 10-30% ______________________________________
摘要:
Covulcanizable compositions comprising (A) 55-100% by weight of an elastomeric copolymer of vinylidene fluoride with perfluoropropene optionally tetrafluoroethylene and containing from 0.001 to 2% by weight of bromine; (B) 0-45% by weight of a tetrafluoroethylene and propylene copolymer; (C) 0.7-2.5 parts for 100 parts of mix (A)+(B) of a bisphenol compound; (D) 0.3-1.5 parts for 100 parts of mix (A)+(B) of an organic guaternary compound of ammonium, phosphonium or aminophosphonium; (E) 0.4-5 parts for 100 parts of mix (A)+(B) of an organic peroxide; (F) 1-5% by weight of (A)+(B) of a peroxide cross-linking coagent.
摘要:
A continuous process for applying subgaskets to surfaces of CCM subassemblies, comprising: a) preparation of a roll (A), wherein on each of two surfaces, electrocatalytic layers longitudinally distributed at regular intervals are applied; b) preparation of two subgasket rolls (B) wherein, on a subgasket sheet, in correspondence to the position of the electrocatalytic layers in the roll (A), openings are made; the percent ratio (subgasket opening area)/(electrocatalytic layer area) being between 90% and 99%; c) hot lamination of two rolls (B) with the roll (A); the step being carried out so that the perimeter of the openings of the two rolls (B) falls inside the area of the electrocatalytic layers, and obtaining a roll (C), wherein on each of the two surfaces of the sheet formed of a CCM sequence (roll (A)) a subgasket sheet (roll (B)) is applied.