Expanded PTFE Articles With Seam-Free Long-Length Stability
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Solution Overview
Problem
Existing methods for producing long lengths of unsintered paste extruded PTFE articles, such as films and tapes, fail to maintain consistent dimensional, mechanical, and electrical properties due to the presence of joints or seams, leading to undesirable variations and potential breakage during cable or wire assembly.
Innovation Solution
A method involving larger preforms and modified mixing, compaction, and extrusion processes to achieve homogeneous mixtures, using a single batch of raw materials and controlled compaction pressures to reduce thickness variation and improve mechanical and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If successive preforms are paste extruded to generate long lengths of monolithic PTFE articles, then the length of the article is increased, but the number of joints or seams increases leading to high variation in dimensional parameters, mechanical properties, electrical properties, and porosity
Solution Approach 1:
The patent merges multiple successive preforms into a single continuous monolithic structure by eliminating joints through a specialized paste extrusion process. The process combines preforms in such a way that their interfaces become indistinguishable, creating a unified structure without seams that would otherwise compromise dimensional and property consistency.
Solution Approach 2:
The patent extracts and eliminates the harmful joints or seams that naturally occur when successive preforms are joined. By removing these discontinuities through a refined paste extrusion process, the article achieves uniform dimensional parameters, mechanical properties, electrical properties, and porosity throughout its entire length.
2Productivity
If traditional paste extrusion processes are used to produce long lengths of PTFE articles, then production efficiency is maintained, but dimensional parameters and mechanical properties cannot be maintained within necessary tolerances over long lengths
Solution Approach 1:
The patent changes critical process parameters in the paste extrusion method, including paste composition, extrusion pressure, temperature profiles, and drying conditions. These parameter modifications enable the production of long monolithic articles while maintaining dimensional parameters and mechanical properties within necessary tolerances throughout the entire length.
Solution Approach 2:
The patent applies preliminary actions by carefully controlling the paste preparation, preforming, and extrusion conditions before the actual formation of the long article. This preliminary optimization of process parameters ensures that the final product maintains consistent properties over long lengths without compromising production efficiency.
3Length of moving object
If joints or seams are present in long lengths of PTFE articles, then the article can be produced in continuous lengths, but the mechanical strength at joint locations is reduced leading to potential breakage during winding or assembly
Solution Approach 1:
The patent merges successive preforms into a unified monolithic structure where the interfaces between preforms are eliminated. This merging process ensures that no weak joint locations exist, maintaining uniform mechanical strength throughout the entire continuous length of the article, preventing breakage during winding or assembly operations.
4Length of moving object
If successive preforms are used to create long PTFE articles, then the article can be manufactured in achievable lengths, but distinct joints can be identified and cause reduced electrical performance due to low spots in insulative properties
Solution Approach 1:
The patent extracts and eliminates the distinct joints or seams that compromise electrical performance. By removing these discontinuities through a refined paste extrusion process, the article achieves uniform insulative properties without low spots, ensuring consistent electrical performance throughout the entire length.
Solution Approach 2:
The patent modifies process parameters including paste composition, extrusion conditions, and drying profiles to eliminate joint formation. These parameter changes ensure that successive preforms merge into a monolithic structure with uniform electrical properties, maintaining reliability and consistent insulative performance over long lengths.
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 results in PTFE articles with reduced joint size and improved consistency of properties over long lengths, enhancing mechanical strength and electrical performance in cable or wire assemblies.
Implementation Method 1
The mixture is then compacted to a desired density
Implementation Method 2
The compacted mixture is then extruded through a die to form the PTFE article
Data Source
Figure 1
Figure 2~4B
Figure 5~7
AI summary
The present disclosure relates to methods of making an article comprising PTFE, methods of making expanded articles comprising PTFE, articles comprising PTFE, and expanded articles comprising PTFE having improved mechanical and electrical performance and particularly reduced variability in mechanical, electrical and dimensional properties, particularly over long lengths.