| 摘要 |
<p>The assemblies consist of an absorbent, fibrous carrier, e.g. if card, at least part of the surface of which is covered by a non-porous diffusion wall of olefinic polymer 150 mu thick, (pref. 15-80 mu). The carrier is impregnated with (a) 40-90% w/w phosphate ester (I) of formula (RO)(R1O)(R2O)-P=O, where R and R1=1-4C alkyl, R2=CyR3.CR4Y2 or -CR3=CR4Y, Y=F, Cl or Br, and R3 and R4=H, F, Cl, Br, Me or Et, and if vapour press. >=10-3 Torr at 20 degrees, (b) >=1 stabiliser of volatility less than or equal to that of (I), e.g. an epoxy deriv of a vegetable oil, aliphatic alcohol, diol or 6-24C aliphatic mono- or dicarboxylic acid, (c) 1-40% of a second org. cpd soluble in (a) + (b) with vapour press. 0.2 Torr at 25 degrees C defined by log p + 7.5 (u.d/epsilon) = 2.4-3.4 where p=vapour press. at 25 degrees C in 103 Torr; mu=dipole moment at 25 degrees C in 1018 e.s.u. (CGS); d=density at 25 degrees C w.r.t. water at 4 degrees C and epsilon=dielectric constant. Suitable cpds include benzene or naphthalene derivs.</p> |
