Process for the Preparation of a Polyethersulfide

摘要

Process for the production of a mercapto-terminated liquid polymer with the formula HS—R—(Sy—R)t—SH, wherein each R is independently selected from branched alkanediyl or branched arenediyi groups and groups with the structure —(CH2)p—O—(CH2)q—O—(CH2)r- and wherein 0-20% of the number or R-groups in the polymer are branched alkanediyl or branched arenediyl groups and 80-100% of the number or R-groups in the polymer have the structure —(CH2)p—O—(CH2)r—, wherein t has a value in the range 1-60, y is an average value in the range 1.0-1.5, q is an integer the range 1 to 8, and p and r are integers the range 1-10. The resulting polymer has an improved ability of recovering its original shape after release from deforming compression forces and improved tendency to recover during the application of those forces

主权项

1. A process for the production of a mercapto-terminated liquid polymer with the formula
HS—R—(Sy—R)t—SH   (I) wherein each R is independently selected from branched alkanediyl or branched arenediyl groups and groups with the structure —(CH2)p—O—(CH2)q—O—(CH2)r— and wherein 0-20% of the number or R-groups in the polymer are branched alkanediyl or branched arenediyl groups and 80-100% of the number or R-groups in the polymer have the structure —(CH2)p—O—(CH2)q—O—(CH2)r—, wherein t has a value in the range 1-60, y is an average value in the range 1.0-1.5, q is an integer the range 1 to 8, and p and r are integers the range 1-10, said process comprising the following steps:
a) forming a polymer by reacting a bis(haloalkyl)formal with alkali polysulfide of the average formula M2Sx, wherein M is an alkali metal and x is an average value in the range from 1.04 to 1.8,b) reacting said polymer with a reducing agent in an aqueous reaction mixture, thereby reductively splitting polysulfide linkages, andc) lowering the pH of the mixture resulting from step b) to below 6.0 by adding an acid.