Polyarylene Sulfide Washing Solvent Composition
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional washing techniques for polyarylene sulfides often result in residual malodorous compounds and increased melt viscosity due to the use of acetyl compounds and other organic solvents, which are undesirable and affect the polymer's properties.
Innovation Solution
A method involving a washing solution with controlled compositions of water and aprotic organic solvents, specifically between 30 wt.% to 70 wt.% each, is used to minimize oligomer content and maintain low melt viscosity in polyarylene sulfides, employing a sedimentation column for effective separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If acetyl compounds (acetone) are used for washing polyarylene sulfide, then the reaction solvent and oligomers are quickly removed, but residual malodorous compounds remain in the polymer
Solution Approach 1:
The patent changes the chemical composition parameters of the washing solution by replacing pure acetyl compounds with a mixed solvent system comprising water (30-70 wt%), aprotic organic solvent (30-70 wt%), and optionally carboxylic acid (0.1-10 wt%). This parameter change allows the washing solution to effectively remove oligomers and impurities while avoiding the accumulation of malodorous residual compounds that occur with conventional acetone washing.
2Object-generated harmful factors
If alternative organic solvents are used for washing, then malodorous compounds are reduced, but the oligomers are excessively solubilized causing substantial increase in melt viscosity
Solution Approach 1:
The patent optimizes the concentration parameters of the washing solution components, specifically controlling the water content (30-70 wt%) and aprotic organic solvent content (30-70 wt%). This balanced composition provides sufficient solubility to remove malodorous compounds while limiting excessive oligomer solubilization that would increase melt viscosity. The optional carboxylic acid addition (0.1-10 wt%) further refines the washing effectiveness without adversely affecting viscosity.
3Manufacturing precision
If conventional washing solutions are used, then impurities are removed, but the oligomer content increases leading to higher melt viscosity
Solution Approach 1:
The patent modifies the washing solution composition parameters to achieve optimal balance between impurity removal and oligomer content control. The specific formulation of water (30-70 wt%), aprotic organic solvent (30-70 wt%), and carboxylic acid (0.1-10 wt%) creates a washing environment that effectively removes impurities while minimizing oligomer dissolution, thereby maintaining low melt viscosity in the final polyarylene sulfide product.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method achieves a polyarylene sulfide with reduced oligomer content, lower melt viscosity, and a narrow particle size distribution, while maintaining a low crystallization temperature and weight average molecular weight, thereby improving the polymer's processing characteristics.
Implementation Method 1
contacting a slurry of the polyarylene sulfide with a washing solution, wherein the washing solution contains from about 30 wt. % to about 70 wt. % of water and from about 30 wt. % to about 70 wt. % of an aprotic organic solvent
Implementation Method 2
a sedimentation column that is configured to receive the slurry of the polyarylene sulfide and the washing solution
Data Source
AI summary
A method for washing a polyarylene sulfide with a washing solution that contains a carefully controlled solvent content is provided. More particularly, the washing solution typically contains water (e.g., deionized water) in an amount of from about 30 wt. % to about 70 wt. % and an aprotic organic solvent in an amount of from about 30 wt. % to about 70 wt. %. Within such carefully controlled ranges, the present inventors have discovered that the polyarylene sulfide can retain a relatively high oligomer content, which in turn, helps minimize the melt viscosity.