Hybrid Impact Modifiers for PVC Dispersion Homogeneity
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Solution Overview
Problem
Existing methods for impact strengthening of PVC using polymeric impact modifiers and mineral fillers often result in dispersion and concentration heterogeneities, as well as segregation issues, particularly when the mineral filler content exceeds 2-3% of the organic impact modifier content, affecting the homogeneity and flowability of the final powder product.
Innovation Solution
The solution involves mixing polymeric impact modifiers with mineral fillers in a water-dispersed phase, followed by standard recovery processes like spray drying or coagulation, ensuring intimate mixing of organic and inorganic phases, either simultaneously introducing the latex and slurry into the drying chamber or after achieving homogeneity, to produce hybrid impact modifiers with improved powder properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mineral filler is added as powder into impact modifier powder during or after recovery, then powder properties (flowability, lumping resistance) are improved, but dispersion heterogeneity and concentration non-uniformity occur
Solution Approach 1:
The mineral filler is introduced into the latex slurry before the polymerization and recovery processes, allowing it to be incorporated into the polymer matrix during formation. This preliminary incorporation ensures uniform distribution of filler throughout the impact modifier powder, eliminating segregation and concentration heterogeneity while maintaining good flowability properties
2Ease of operation
If mineral filler content exceeds 2-3% of organic impact modifier content, then powder flowability is improved, but segregation issues and concentration heterogeneity worsen
Solution Approach 1:
The mineral filler particles are merged with the polymer matrix during the emulsion polymerization process, creating a unified hybrid structure where filler and polymer are intimately mixed at the molecular level. This merging prevents segregation even at high filler loadings, as the filler becomes an integral part of the polymer network rather than a separate phase
3Ease of manufacture
If mineral filler is added after polymer formation, then processing simplicity is maintained, but dispersion quality and homogeneity deteriorate
Solution Approach 1:
The mineral filler is introduced into the latex slurry before polymerization begins, allowing it to be trapped and distributed within the polymer matrix as it forms. This preliminary action achieves superior dispersion quality without complicating the manufacturing process, as the filler incorporation occurs automatically during the standard emulsion polymerization procedure
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
This approach enhances the dispersion and homogeneity of the mineral filler within the thermoplastic matrix, preventing segregation and improving the flowability and caking resistance of the hybrid impact modifier powder, resulting in improved impact performance and compatibility with the host polymer matrix.
Implementation Method 1
the polymeric modifier is dispersed into a water phase (latex, suspension or slurry)
Implementation Method 2
spray drying, coagulation, freeze coagulation or other known recovery methods
Implementation Method 3
This powder is mixed with this thermoplastic matrix either in the molten state or dry blended with the powder of thermoplastic matrix
Data Source
AI summary
The present invention relates to hybrid impact modifiers prepared by: either spray drying, coagulation, freeze coagulation or other known recovery methods of a mixture of a latex or slurry of standard impact modifiers and a slurry of a mineral filler, or simultaneous drying (by spray-drying, coagulation other known recovery possible methods) of (i) a latex or slurry of standard impact modifiers and of (ii) a slurry of a mineral filler, further to the coagulation or freeze coagulation, if any, there is a filtration and drying step to recover these hybrid impact modifiers as a powder. The present invention also relates to the use of said hybrid impact modifiers in thermoplastic polymers, and a thermoplastic polymer containing said hybrid impact modifiers. The hybrid impact modifiers may exhibit improved powder properties (flowability, lumping/caking resistance, segregation between the organic and the mineral parts) and better dispersion homogeneities.