摘要:
A method for the concentration of water-in-oil emulsions of water soluble vinyl addition polymers is disclosed. The process involves distilling the water-in-oil emulsion of the water soluble vinyl addition polymer under a vacuum while maintaining the water-oil phase ratio substantially equal to the starting latex. Maintaining this ratio allows latices of this type to be concentrated to as high as 70% by weight polymer.
摘要:
Polysuccinimide is produced by thermal polymerization of a precursor or a reactant admixture that includes an unsaturated compound in a plate-type reactor at temperatures sufficient to initiate polymerization and to form a brittle solid. The so-obtained polysuccinimide can be hydrolyzed to polyaspartic acidor to a polyaspartic acid salt, if desired. The precursor can be a monomer or a mixture of reactants that form polymerizable intermediates.
摘要:
A method for preparing substantially dry homopolymers and copolymers which comprises forming a polymeric latex or water-in-oil emulsion and partially inverting said latex by regulated contact time with water in the time span 0.5 - 10.0 seconds and preferably less than 1 second. A preferred operation is carried out in a static mixer where the contact time for inversion is regulated by the diameter or length of a cylindrical tube containing static baffles.
摘要:
The present invention is directed to a method for the production of D,L-aspartic acid. The method comprises reacting an unsaturated dicarboxylic acid or anhydride, such as, maleic acid, fumaric acid, maleic anhydride, or mixtures thereof, with excess aqueous ammonia at an elevated temperature and pressure for a time sufficient to produce diammonium D,L-aspartate. The produced diammonium D,L-aspartate is then neutralized to D,L-aspartic acid. Excess unreacted ammonia and various by-products may be recycled and re-used in the method, thereby minimizing waste and reducing cost. The produced D,L-aspartic acid may be subsequently used to make polyaspartic acid.
摘要:
A method for the preparation of a desired molecular weight polysuccinimide by the catalytic polymerization of aspartic acid in the presence of a thioether solvent. Polysuccinimide of relatively high weight average molecular weight and high purity can be produced in relatively high yields while employing a relatively low catalyst loading and relatively low temperatures.
摘要:
The present invention is directed to a method for the production of D,L-aspartic acid. The method comprises reacting an unsaturated dicarboxylic acid or anhydride, such as, maleic acid, fumaric acid, maleic anhydride, or mixtures thereof, with excess aqueous ammonia at an elevated temperature and pressure for a time sufficient to produce diammonium D,L-aspartate. The produced diammonium D,L-aspartate is then neutralized to D,L-aspartic acid. Excess unreacted ammonia and various by-products may be recycled and re-used in the method, thereby minimizing waste and reducing cost. The produced D,L-aspartic acid may be subsequently used to make polyaspartic acid.