Fiber Composite Impregnation via Monomer Atomization
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Solution Overview
Problem
Existing processes for producing fiber composite materials face issues with high melt viscosity of polyamide 6, leading to limited process speed and frequent clogging in production lines due to premature polymerization of caprolactam melts, resulting in production downtime and increased energy costs.
Innovation Solution
A process involving the application of a liquid monomer mixture containing a cyclic amide and an activator or catalyst using a three-component nozzle, with droplet sizes less than 200 microns, which are polymerized at temperatures between 120°C to 300°C, avoiding unnecessary melting and solidification steps and preventing pipeline clogging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If caprolactam melt is applied to fiber material for impregnation, then impregnation efficiency is improved, but polymerization occurs in feed lines causing clogging and production downtime
Solution Approach 1:
The patent applies a preliminary protective action by introducing an inert atmosphere (nitrogen or carbon dioxide) into the feed lines and application equipment before introducing the caprolactam melt. This preliminary inerting prevents premature polymerization by excluding oxygen and moisture, thereby maintaining production continuity while preserving impregnation efficiency.
Solution Approach 2:
The patent uses an inert gas (nitrogen or carbon dioxide) as an intermediary substance that mediates between the caprolactam melt and the reactive environment. The inert gas creates a protective atmosphere in the feed lines and application equipment, preventing harmful polymerization reactions while allowing the impregnation process to proceed efficiently.
2Stability of the object's composition
If caprolactam melt is cooled and converted to solid powder for storage, then storage stability is improved, but additional melting step is required increasing energy consumption
Solution Approach 1:
The patent maintains the caprolactam melt in a continuous molten state throughout the impregnation process by providing continuous heating and using inert atmosphere protection. This eliminates the discontinuous cooling-to-powder-and-reheating cycle, thereby maintaining storage stability through chemical protection while avoiding the energy penalty of repeated phase changes.
Solution Approach 2:
The patent changes the environmental parameters (introducing inert atmosphere and maintaining elevated temperature) to allow the caprolactam to remain stable in the molten state without premature polymerization. This parameter change eliminates the need for phase transition to solid powder for storage stability, thereby reducing energy consumption while maintaining compositional stability.
3Manufacturing precision
If high pressure is used to introduce molten polyamide 6 into dry fiber product, then impregnation completeness is improved, but process speed is limited due to high melt viscosity
Solution Approach 1:
The patent changes the physical state parameter of the polyamide from high-viscosity melt to low-viscosity monomer (caprolactam). This parameter change allows impregnation to proceed at higher speeds without compromising completeness, as the monomeric form has significantly lower viscosity and can penetrate the fiber structure more rapidly while still achieving complete impregnation through subsequent polymerization.
4Productivity
If activated caprolactam melt is prepared in advance, then impregnation effectiveness is improved, but polymerization occurs on mixing elements and application devices causing blockages
Solution Approach 1:
The patent applies preliminary protection by introducing inert atmosphere into the feed lines and application equipment before introducing the activated caprolactam melt. This preliminary inerting prevents polymerization on mixing elements and application devices, thereby maintaining impregnation effectiveness while reducing maintenance requirements and avoiding blockages.
Solution Approach 2:
The patent uses inert gas (nitrogen or carbon dioxide) as an intermediary that protects the activated caprolactam melt from premature polymerization on contact with equipment surfaces. This intermediary protective atmosphere allows the activated melt to be handled and applied effectively without causing blockages or increasing maintenance complexity.
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 efficient impregnation of fibers with economically viable polymerization times, producing fiber composite materials with good mechanical properties and minimizing production disruptions, while maintaining high fiber content and reducing residual monomer content.
Implementation Method 1
the average droplet size of the respective monomer mixtures a1) and a2) is less than 500 μm, is particularly less than 200 microns
Implementation Method 2
b) the monomer mixtures applied after step a) are polymerized at a temperature of 120 to 300 °C
Implementation Method 3
a crosslinked structure is formed which has a gel fraction of more than 5%, particularly of more than 10%, viewed in section
Data Source
Figure 1
AI summary
The invention relates to a method for the production of fiber composite materials by means of special application of monomer mixtures to a fiber material surface and subsequent polymerization.