Comminutable Polyester Powder Production via Freezing
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Solution Overview
Problem
Conventional methods fail to produce polyester powders, particularly water soluble ones like polylactides and polyglycolides, due to low glass transition temperature, leading to high production costs and contamination issues with solvents and surfactants, limiting their use in applications such as the oil industry.
Innovation Solution
Chemical pre-treatment or irradiation is used to render polyesters comminutable, followed by comminution to produce powder form, eliminating solvent and surfactant contaminants, and enabling scalable production of powders from commercially available resins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional grinding methods are used on polyesters with low glass transition temperature, then the process is simple and low cost, but the polyester cannot be comminuted effectively
Solution Approach 1:
The patent applies preliminary action by pre-freezing the polyester material to its glass transition temperature or below before grinding. This preliminary freezing step transforms the material from a soft, ungrindable state to a hard, comminutable state, enabling subsequent effective grinding while maintaining process simplicity
Solution Approach 2:
The patent changes the temperature parameter of the polyester material to below its glass transition temperature, which fundamentally alters the material's mechanical properties from soft and elastic to hard and brittle, making it suitable for conventional grinding processes
2Productivity
If solvent based methods are used to produce polyester powders, then powders can be produced, but solvent traces remain contaminating the powder
Solution Approach 1:
The patent extracts and eliminates the solvent step entirely from the process, replacing it with a freezing-grinding method that produces powder without any solvent involvement, thereby completely removing solvent contamination concerns
Solution Approach 2:
The patent replaces the chemical/solvent-based powder production method with a physical method combining freezing and mechanical grinding, substituting chemical processes with physical transformations to achieve powder production without contamination
3Productivity
If emulsion polymerisation or dispersion methods are used, then polyester powders can be produced, but high concentrations of surfactant remain in the product
Solution Approach 1:
The patent removes the emulsion polymerisation and dispersion steps entirely, replacing them with a direct freezing-grinding approach that produces powder without requiring surfactants, thereby eliminating surfactant contamination
Solution Approach 2:
The patent replaces complex chemical processes (emulsion polymerisation, dispersion) with a simple physical process (freezing followed by mechanical grinding), eliminating the need for surfactants and other chemical additives
4Productivity
If polyester is mixed and co-extruded with filler to produce powders, then grinding becomes possible, but particles comprise mixture of polyester and filler
Solution Approach 1:
The patent extracts and eliminates the filler mixing and co-extrusion steps, using only pure polyester material that is frozen and then ground, thereby producing pure polyester powder without filler contamination
Solution Approach 2:
The patent changes the temperature parameter to freeze the pure polyester, enabling direct grinding of the frozen material without requiring filler addition to alter comminutability
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 process allows for the production of clean, scalable polyester powders suitable for oilfield applications, overcoming the limitations of conventional grinding methods and ensuring biocompatibility and environmental acceptability.
Implementation Method 1
irradiating the polyester
Implementation Method 2
chemical pre-treatment of the polyester
Data Source
AI summary
A process is disclosed for producing a polyester in powder form, which process comprises: (a) rendering a polyester comminutable by (i) chemical pre-treatment of the polyester, or (ii) irradiating the polyester; and (b) comminuting the polyester produced in step (a) to form a powder.