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:
Fluoropolymers comprising a fluoroelastomer matrix incorporating therein particles of a semicrystalline fluoropolymer containing iodine and/or bromine and formed of tetrafluoroethylene (TFE) homopolymers or copolymers wherein the average particle sizes of the semicrystalline fluoropolymer latex range from 10 to 100 nm.
摘要:
This invention relates to perfluoropolyethers having neutral end groups by a process based on the photooxidation of C.sub.3 F.sub.6 and/or C.sub.2 F.sub.4, thereby obtaining controlled molecular weight products having perfluoroalkyl or perfluorochloroalkyl neutral end groups, with high yields of useful products.
摘要:
Mono- or difunctional perfluoropolyethers with hypofluorite end groups, and a process for preparing them which comprises reacting a perfluoropolyether having at least one fluoroformate end group, or containing a peroxy group --O--CF.sub.2 OO--CF.sub.2 --O--, with fluorine in the liquid phase at a temperature ranging from -60.degree. C. to 30.degree. C., in the presence of UV radiation of a wave-length ranging from 200 to 500 nm.
摘要:
Curable (per)fluoropolyether polyurethanes obtained by reaction in a first step of a) (per)fluoropolyether diols having a number average molecular weight from 2,000 to 5,000; with b) diisocyanates of formula OCN—R—NCO (VIA) wherein R is a hydrogenated and/or fluorinated radical; in a second step with the compound c) saturated or unsaturated aliphatic hydrogenated diols, (alkyl)cycloaliphatic, aromatic; oligomers or polymers of butadiene with a number average molecular weight from 500 to 4,000 having end hydroxyl groups; provided that: when the diisocyanate b) is used and the radical R in formula (VIA) is: —Ph—CH2—Ph—, the hydrogenated diols c) are optional; when the radical R has a meaning different from that above mentioned, at least one of the used hydrogenated diols c) is selected from those belonging to the c2)-c6) groups; the sum of the equivalents of the compounds a) and c) being equal to the equivalents of the compound b).
摘要:
Fluoroelastomers curable by ionic route based on vinylidene fluoride (VDF) comprising: a) 100 parts by weight of fluoroelastomer based on vinylidene fluoride (VDF) substantially polar end group free; b) from 0.05 to 5 phr of accelerant; c) from 0.5 to 15 phr of curing agent; d) from 1 to 40 phr of one or more inorganic acid acceptors, preferably bivalent metal oxides; e) from 0 to 2.5 phr, preferably from 0 to 1.5 phr of one or more basic compounds preferably hydroxides of bivalent metals or of weak acid metal salts; f) from 0 to 80 phr of reinforcing fillers.
摘要:
Compounds comprising a peroxide and a curable blend by peroxidic way, consisting essentially of hydrocarbon elastomers containing at least an acrylic monomer, and of unsaturated fluorinated elastomers obtained by dehydro halogenation of fluorinated VDF-based elastomers, said fluorinated elastomers having in the polymer chain at least 5% by moles of hydrogenated C1 groups of the type —CH2— and/or —CH3, the amount of unsaturated fluorinated elastomer in the elastomeric blend being comprised from 1 to 99% by weight.
摘要:
Curable fluoroelastomeric compositions comprising: A) 100 phr (parts) of fluoroelastomeric copolymers based on vinylidenefluoride (VDF) copolymers and at least a partially or completely fluorinated comonomer having an ethylene unsaturation; B) 0.5 to 10 phr of a curing agent having the general formula [(R3—Si)m—(CyM2y—O—CzM2z)p—(CtM2t−1)n—Pq—O—]2Q wherein m, q are independently 0 or 1; p=0, 1, 2 or 3; n=0, 1 or 2; y, z are each from 1 to 20; t is from 3 to 10; R is selected from the group consisting of a CxM2x+1 linear or branched aliphatic chain containing hydrogen and/or fluorine (M=H and/or F), a CxM2x−1 cycloaliphatic structure containing hydrogen and/or fluorine, a CxMx−1 aromatic structure containing hydrogen or fluorine (wherein x in the formulas is an integer from 1 to 20) and Pa wherein P is a bivalent (per)fluoropolyether linking group and a is an integer from 0 to 1; Q is selected from the group consisting of an aromatic or an aliphatic structure, an aromatic structure containing nitrogen or oxygen and a structure having the following formula —S1—C(S2)—C(S3)—Z—C(S4)—C(S5)—S6— wherein S1, S2, S3, S4, S5 and S6 are equal to or different from each other, and are H or C1-C5 alkyls and Z is a C1-C18 alkylene or cycloalkylene radical, linear or branched, optionally containing oxygen and/or fluorine atoms, or a bivalent (per)fluoropolyoxyalkylene radical P; with the proviso that when p is different from 0, m=1 and n=q=0; when n is different from 0, m=p=q=0; and when q is different from 0, m=1 and p=n=0; and C) an accelerant being an onium-organic compound having a positive charge in an amount from 0.05 to 5 phr.
摘要:
Perfluoropolyethers having an acid end group of the type of acyl fluoride (or chloride) or a carboxylic group or derivatives thereof, the other end group being a perfluoroalkyl containing one or two halogen atoms different from fluorine, are prepared by photooxidation of C.sub.3 F.sub.6 and/or C.sub.2 F.sub.4, in the presence of a fully halogenated ethylene containing 1 to 4, preferably 1 or 2 atoms of halogen different from fluorine, and by the subsequent thermal of photochemical decomposition treatment of the peroxide groups which are present in the photooxidation product.