| 摘要 |
<p>The impact strength and dimensional stability of an article made from a copolymer of an unsaturated nitrile are improved by stretching in more than one direction in a linear stretch ratio of 1.5-5:1 in each direction at 85-150 degrees C. and retaining the article in its stretched condition at this temp. for 5-150 secs. The copolymer is prepd. in aq. medium from 60-90 wt. % CH2=CRCN, where R is H, 1-4C alkyl or halogen, and 10-40 wt. % of an easter CH2=CR1COOR2, where R1 is H, 1-4C alkyl or halogen, and R2 is 1-6C alkyl, or an olefin CH2=CR3R4, where R3 and R4 are 1-7C alkyl, or an ether CH2=CH-O-R5 where R5 is 1-4C alkyl, or vinyl acetate or styrene. Those monomers are copolymerised in the presence of 0-40 wt. % of a rubbery polymer of 50-100 wt. % butadiene or isoprene and 0-50 wt. % styrene or CH2=CRCN. Used in bottles and films having improved tensile impact strength. In an example, a rubber latex was prepd. from 60 wt. % butadiene and 40 wt. % acrylonitrile. 31.0 pts. of latex were mixed with 75 pts. acrylonitrile and 25 pts. methyl acrylate and polymerisation was at 60 degrees C. for 20 hrs. using 0.06 pts. potassium persulphate. 30 mil. sheet was formed from the resin by extrusion and calendering, and was stretched x 3.u in two directions.</p> |
