Removing residual monomers etc. from aq. polymer dispersions - by passing through the dispersion a stream of inert gas contg. specified vol. of water to gas

    公开(公告)号:DE4118526A1

    公开(公告)日:1991-12-19

    申请号:DE4118526

    申请日:1991-06-06

    Applicant: BASF AG

    Abstract: Process is claimed for removing residual monomers and low-mol wt. impurities (I) from polymers in aq. dispersion by passing through the dispersion a stream of gas produced by means of a distributor device, the novelty is that the gas stream contains 0.01-0.5-1 liq. water per 100-1 gas. The process can be used with aq. dispersions (pref. 40-60 wt. %) of various polymers (based on styrene, olefins, dienes, acrylonitrile, acrylate, vinyl ethers, etc. contg. up to 1500 ppm (I), pref. the dispersion is treated at 70-80 deg.C with a stream of gas (nitrogen, air, etc) contg. water at 10-30 deg.C then worked up e.g. by spray drying. USE/ADVANTAGE - The process enables the removal of (I) from polymer dispersions without the disadvantages of prior art processes (high cost of steam treatment, breakdown of dispersions, coagulation).

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