| 摘要 |
<p>Vulcanisable compsns. comprise (1) 100 pts. vinylidene fluoride elastomeric copolymer with ethylenically unsatd. fluorinated and chlorofluorinated monomer(s), (2) 1-40 pts. inorganic acid acceptor comprising basic metal oxides namely MgO, CaO, PbO, ZnO and/or basic Pb phosphites opt. in the form of cationic complexes or chelates, (3) 0.5-10 pts. wt. basic cpds. comprising Ca, Sn or Ba hydroxide, metal salts of weak acids e.g. Ca, Sr, Ba, Na or K carbonates, benzoates or phosphates opt. in the form of complexes with normal chelates or cationic complexes known in Cu chemistry, (4) 0.5-1.5 pref. 1-6 pts. wt. vulcanising agents based on polyhydroxy and/or polythiol cpds. of formula A(BC)n and/or CB-R'-BC (where A is arylene group; n is >=2; B is O or S; C is H or alkali metal; R' is (cyclo)alkylene, mono- or polyalkylenecycloalkyl, alkylenediaryl or oxyalkylenediaryl), and as an improvement, (5) 0.05-5 pts. wt. of an accelerator. The accelerator is based on a salt or hydroxide of a heteroxyclic cation, contg. 1 or 2 heteroatoms of formulae (I),(II), or (III): where Z is N or P; R' and R2 are H or 1-4C alkyl; Q is CHR' O, S, SO2, NR5, PR5, NH or orthophenylene; n is 0-4 and m is 1-4, pref. m and n are 1 or 2; R3, R4 and R5 are 1-18, pref. 1-12C (cyclo)alkyl, aryl, arylalkyl, oxyalkyl or polyoxyalkyl with opt. etherified terminal OH group; Y- is (in)organic monovalent anion e.g. halide, chlorate, perchlorate, fluorinated nitrate, acetate, oxalate, stearate, chloroacetate, p-toluenesulphonate or OH. The compsn. can be moulded by successive extrusion and vulcanisation or by simultaneous injection stamping and vulcanisation without scorching or tearing. The prods. have optimum compression strength, good thermal ageing and chemical resistance and have good adhesion with metal substrates even at high temps. e.g. >=250 degrees C. Applications include gaskets, linings, cable sheaths, etc.</p> |
