摘要:
Use for the paper sizing of aqueous polyurethane dispersions from (per)fluoropolyethers obtainable by reaction among the following compounds:
a) (per)fluoropolyether diols having a number average molecular weight from 400 to 5,000; b) diisocyanates having formula:
OCN-R-NCO (VIa)
wherein R is an aliphatic, cycloaliphatic bifunctional radical; or an aromatic bifunctional radical; c) diols containing one carboxylic function and optionally one or both the following components: d) hydrazine and/or aliphatic diamines; e) monofunctional hydroxylic (per)fluoropolyethers having a number average molecular weight in the range 300-1,000.
摘要:
Fluorinated oligourethanes, having number average molecular weight lower than or equal to 9,000, having a branched structure, formed of the following monomers and macromers: a) aliphatic, cycloaliphatic or aromatic polyisocyanates, b) heterofunctional hydrogenated monomers having general formula:X0-(CR1AR2A)b-Y0 one or more of the following compounds: c) bifunctional hydroxyl (per)fluoropolyethers (PFPE diols) having number average molecular weight in the range 400-3,000, e) monofunctional hydroxyl (per)fluoropolyethers or monofunctional hydroxyl (per)fluoroalkanes (e'), having number average molecular weight in the range 300-1,000, and optionally the following compunds: d) heterofunctional monomers, dI) hydrogen-active compounds, capable to form bonds with the NCO functions stable at the hydrolysis but weak at heat.
摘要:
Use of fluorinated polymers based on fluoropolyethers for the preparation of crosslinkable high dry formulations comprising a fluorinated part R F and optionally an hydrogenated part R H , not containing groups capable of linking by means of hydrogen bonds to basic acceptors, an hydrogenated part Rh 1 and Rh 2 , wherein Rh 1 is equal to or different from Rh 2 , and Rh 1 and/or Rh 2 being linking bonds containing at least a functional group capable of linking by means of hydrogen bonds with basic acceptors, the bonds joining the fluorinated part to the hydrogenated part being of ether C-O simple type, the terminals T' a and T'' being such as to render the structure mono-, bi- or polyfunctional, and subsequent crosslinking of the fluorinated polymer, the monofunctional products being always in admixture with a resin having even a higher functionality than the described type; the preferred fluorinated products have the formula:
T''-(Rh 2 ) y (R H ) x -R F -(R H ) x -(Rh 1 ) y' T' a
摘要:
Fluorinated thermoplastic elastomers having a block structure:
-[-R f -H₁-H₂-H₁-]-
where -R f - is a perfluoropolyoxyalkylene sequence of formula:
-CF₂O-(CF₂CF₂O) m -(CF₂O) n -CF₂-
with m/n = 0.2 + 5, H₁ and H₂, equal or different from each other, are bivalent radicals having arylene, alkylarylene, alkylene or cycloalkylene structure, optionally containing fluorine and/or other heteroatoms selected among oxygen, sulphur, nitrogen. Such products are obtainable by utilizing a perfluoropolyoxyalkylene diol having a functionality at least equal to 1.97, preferably at least equal to 1.99, and are characterized by a tensile strength at 23°C at least 50% higher than that of the corresponding polyesters obtained starting from perfluoropolyoxyalkylene diols having a functionality not higher than 1.96.
摘要:
A process for separating from one another the non-functional, monofunctional and bifunctional species in perfluoropolyoxyxalkylenes of gerneral formula X-O-Rf-Y where: Rf = a perfluoropolyoxyalkylene chain comprising monomeric units of formulas (CF₂O), (CF₂CF₂O), (CF₂CF₂CF₂O), X, Y, like or different from each other, are non-functional end groups containing functions OH and/or NH₂, with at least X and Y in parts of such perfluoropolyoxyalkylenes being or containing a group -OH, which consists in subjecting said perfluoropolyoxyalkylenes to column chromatography using, as eluents, non-polar fluorinated solvents, either alone or in admixture with polar solvents.
摘要:
Additives for hydrogenated resins obtainable by using the following components:
a) bifunctional perfluoropolyethers having a -COOR end group, optionally in admixture with monofunctional perfluoropolyethers having a -COOR end group, b) mono, bi or polyfunctional hydrogenated monomers having functional groups able to react with the -COOR end groups of compound a); c) polyolefins having functional groups able to react with the block oligomer/polymer obtained by reaction of a) with b), preferably said functional groups being obtained by grafting with maleic anhydride; reacting in a first step a) with b), until disappearance of the -COOR group of component a), and in a second step the product obtained from the reaction of a) with b) with the functionalized polyolefins c).
摘要:
Use of a composition for preparing by radical route polymeric films having refractive index lower than 1.400, said composition comprising:
a) a perfluoropolyether of formula:
T'-R f- T (Ia)
b) from 0.1 to 10% by weight of a perfluoropolyether of formula:
T-R f -CH 2 OH (Ib)
c) from 0 to 30% by weight of compounds selected from c1):
compounds not containing fluorine: non fluorinated (meth)acrylic esters or vinyl monomers; or c2) compounds containing fluorine: mono(meth)acrylate perfluoropolyethers or perfluoroalkyl mono(meth)acrylates,
d) from 0.01 to 10% by weight of a photoinitiator and/or radical initiators, the amount of component a) being the complement to 100 of the composition, with the proviso that defining by B 0 the mole number of -CF 2 CH 2 OH and by B 1 the sum of the moles of the (meth)acrylic end groups, the (B 0 + B 1 )/B 1 ratio is in the range 1.50-1.01.