| 摘要 |
Homopolymers and copolymers are obtained from 3 - perfluoroalkoxy - 1,1 - dihydroperfluoropropyl acrylate monomers of the formula CH2 : CHCOOCH2CF2CF2O(CF2)nF where n is 1 to 4. Copolymers may be obtained with butadiene, styrene, acrylonitrile, isoprene, vinyl ethers, acrylates, methacrylates, and halogen derivatives thereof such as perfluorobutadiene and fluoroprene, and with 1,1-dihydroperfluoroalkyl acrylate esters of formula CH2 : CHCOOCH2CnF2n+1. Latex dispersions are obtained by heating and stirring the monomer at 50 DEG C. with water, sodium lauryl sulphate, borax and sodium or potassium persulphate. The latex may be diluted and frozen to coagulate the polymer, which may then be dried. Copolymers with 1,1-dihydroperfluoroalkyl acrylate esters (see Specification 703,435) and with butadiene may be similarly prepared. The homopolymers, and copolymers of the monomers with butadiene may be compounded with sodium silicate and calcium hydroxide and cured at 150 DEG C. at 1800 pounds per square inch pressure. Copolymers with butadiene may be compounded with stearic acid, zinc oxide, benzothiazyl disulphide, sulphur and carbon black and cured. Homopolymers may be compounded with stearic acid, carbon black, sulphur and triethylene tetramine and cured. Specification 763,673, [Group IV (b)], also is referred to.ALSO:The invention comprises 3-perfluoroalkoxy-1,1 - dihydroperfluoropropyl acrylate esters of formula CH2:CHCOOCH2CF2CF2O(CF2)nF where n has an integer value of 1 to 4. The esters are prepared by reacting 3-perfluoroalkoxy - 1,1 - dihydroperfluoropropyl alcohols of formula F(CF2)rOCF2CF2CH2OH with acrylic acid using a promoter such as perfluoroacetic anhydride, or by reacting the alcohols with acrylyl chloride (CH2:CHCOCl). In examples: (1) 3-perfluoroethoxy-1,1-dihydroperfluoropropyl acrylate is prepared from the corresponding alcohol and acrylyl chloride in the presence of hydroquinone as a polymerization inhibitor; (2) 3-perfluoropropoxy-1,1-dihydroperfluoropropyl acrylate is prepared from the corresponding alcohol and acrylic acid in the presence of hydroquinone and perfluoroacetic anhydride. The Specification also describes the preparation of the starting material alcohols by reduction with lithium aluminium hydride of esters of perfluoro (b -alkoxypropionic) acids, and the preparation of such esters from the acids, which acids are described in Specifications 763,673. Specification 703,435 also is referred to. |
