| 摘要 |
<p>Bandage with a microbicidal finish for protecting wood consists of a polyurethane-polyurea gel (I), contg. conventional rotting inhibitors. The bandage is used for wooden poles, e.g. telegraph and other poles of pine, fir or spruce wood, which are anchored in the ground, to prevent rotting at ground level. (I) can be produced economically and in reproducible quality. The properties can be optimised to suit the application. In an example, a wooden pole was coated with (I) and then given a protective covering of plastics film or sacking. In the prepn. of (I), 687 (wt.) pts. polyether prepd. from 60 pts. ethylene oxide and 40 pts. propylene oxide, with glycerol as starter (OH no. 28) were heated in 30 min. and stirred 2 h at 120 deg.C with 113 pts. TDI (80% 2,4-, 20% 2,6- isomer), giving a prepolymer with an NCO content of 4.6% and viscosity of 6300 cP at 20 deg.C. 15 pts. prepolymer were stirred into 120 pts. water at +5 deg.C in 3 s. After 80 s, 15g active salt mixt. were added and stirring was continued for 10 s. The mixt. was poured onto polyester fabric, where it set to a gel.</p> |
