Polyether polyol is an important macromolecule raw material, which is mainly used to make various polyurethane materials. In recent years, with the continuous improvement of production technology, the quality of products is also constantly improving, but the odor problem of polyether polyol products has not been well solved, especially the soft foam polyether polyol used in furniture, automobiles, clothing, and other industries. Polyether polyol is directly related to people's daily life, so the odor problem is particularly prominent.
Aldehyde is formed in the decomposition of polyether polyol in the neutralization process. At the same time, there are unreacted propylene oxide monomers, oligomers, and water in the crude polyether polyol. The low volatile matter must be removed by vacuum, and the degassing process will achieve better effects under the nitrogen flow.
With the decrease of the storage temperature, the smell of polyether polyol also decreases. However, when the storage material is cooled to below 50 ℃, the odor of polyether polyol has no obvious change with the extension of time. Therefore, it is stipulated that the material shall be cooled to below 50℃ after passing the circulating filtration and then transferred to the storage tank for preservation.
The partial overheating of the equipment during heating results in the oxygenolysis of polyether polyol. Therefore, in order to ensure that the materials will not contact the overheated wall of the kettle during circulation filtration, it is stipulated in the production that the steam manual valve must be closed before and after the neutralization kettle, filter, and other equipment are used.
In the original neutralization process, water is added first, and then add 85% concentrated acid. In this process, the contact between locally concentrated acid and crude polyether polyol results in the increase of by-products, which also affects the odor of polyether polyol to a certain extent.
Some leakage points will occur at any time due to the vibration, abrasion, and other reasons during the operation of the equipment, which will result in poor gas-tight stability and the odor fluctuation of polyether polyol.