Higher-Crystallinity Polyolefin Dispersions Without Solvents
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Solution Overview
Problem
Conventional aqueous dispersions of thermoplastic resins, particularly polyolefins, are limited in their ability to form higher crystallinity polymers without solvents and are restricted in applications such as coating processes due to their lower crystallinity and requirement for solvent use.
Innovation Solution
The development of aqueous dispersions involving higher crystallinity thermoplastics, specifically polyolefins, is achieved through melt kneading with stabilizing agents and subsequent dilution with water, allowing for the formation of stable dispersions that can be whipped and applied as foams onto substrates without solvents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional aqueous dispersion processes are used for polyolefins, then the process is simple and uses water as medium, but the crystallinity is limited to lower values and solvent is required
Solution Approach 1:
The invention changes the physical-chemical parameters of the dispersion process by using melt extrusion at temperatures above the melting point of the polyolefin (100-200°C) rather than conventional aqueous polymerization. This parameter change enables the formation of dispersions from higher crystallinity polyolefins (up to 80% crystallinity) that were previously impossible with standard aqueous processes
Solution Approach 2:
The invention introduces a dispersing agent as an intermediary substance that facilitates the formation and stabilization of polyolefin particles in water. The dispersing agent (0.1-10 parts by weight per 100 parts polyolefin) acts as a mediator between the hydrophobic polyolefin and hydrophilic water, enabling stable dispersion without organic solvents
2Reliability
If higher crystallinity polyolefins are dispersed in water, then the performance is improved, but solvents are required which creates safety and environmental issues
Solution Approach 1:
The invention extracts and eliminates organic solvents from the dispersion system by using a melt extrusion process where water serves as the continuous phase. The polyolefin is melted and dispersed directly in water with the help of a dispersing agent, removing the need for flammable organic solvents while maintaining dispersion stability and performance
Solution Approach 2:
The invention creates an inert aqueous environment for dispersion that replaces the harmful organic solvent atmosphere. Water as the dispersion medium provides a non-flammable, environmentally benign medium that maintains the stability and performance of higher crystallinity polyolefin dispersions
3Manufacturing precision
If polyolefin dispersions are used in coating processes, then water resistance and chemical resistance are provided, but the layer thickness is limited to more than 15 microns
Solution Approach 1:
The invention changes the particle size and morphology parameters of the polyolefin dispersion through controlled melt extrusion and shearing. This produces finer, more uniform particles that can form coherent films at thicknesses below 15 microns while maintaining the water resistance and chemical resistance properties
4Ease of manufacture
If lower crystallinity polyolefins are used for dispersion, then aqueous dispersion is easier to form, but the heat resistance and mechanical properties are reduced
Solution Approach 1:
The dispersing agent serves as an intermediary that enables easy aqueous dispersion formation while preserving the high crystallinity structure of the polyolefin. The dispersing agent stabilizes the melted polyolefin particles in water without interfering with the crystallization process, allowing the formation of dispersions from high-performance, high-crystallinity materials
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 method enables the creation of coatings and foams with enhanced properties like water resistance, oil resistance, and heat sealability, expanding the application scope of higher crystallinity polyolefins in thin layers and various industrial processes.
Implementation Method 1
aqueous dispersions including: at least one higher crystallinity thermoplastic; at least one dispersing agent; and water
Implementation Method 2
contacting the dispersion of claim 1 with air or other inert gas to form a whipped dispersion
Implementation Method 3
at least partially drying the whipped dispersion to form a foam
Data Source
AI summary
Dispersions and methods for forming dispersions that include a higher crystallinity polyolefin and at least one dispersing agent are disclosed. Various applications for use of the dispersions are also disclosed.