Fibrous Tape Thickness Uniformity via Calendering

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Solution Overview

Problem

Fibrous tapes made from polymeric fibers exhibit thickness variations across their width, which can negatively impact their performance, particularly in applications like antiballistic products where uniform thickness is crucial for consistent mechanical properties.

Innovation Solution

A process involving the calendaring of unidirectionally aligned polymeric fibers at high pressure below their melting temperature, followed by cooling, to produce tapes with a coefficient of variation in thickness across the width of no more than 6%, ensuring uniformity and enhanced mechanical properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If mechanical fusing of adjacent fibers is carried out by spreading and compressing at high pressure below melting temperature, then the tape structure is formed with fused fibers, but thickness variations across the tape width occur

Engineering Contradiction:
Improvefiber fusionVSAvoidthickness uniformity
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by precisely controlling multiple process parameters including temperature (maintained below melting point but sufficient for fusion), pressure (high pressure for fusion), and time (dwell time under pressure). By optimizing these parameters, the process achieves complete fiber fusion while minimizing thickness variations across the tape width, resolving the contradiction between fusion quality and thickness uniformity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements preliminary action by pre-aligning fibers in a unidirectional manner before the fusing process and pre-heating them to the optimal temperature range. This preliminary preparation ensures that when compression is applied, the fibers are already positioned and conditioned for uniform fusion, preventing thickness variations that would otherwise occur during the fusing process

Inventive Principle:
Principle #10Preliminary action

2Strength

If high pressure compression is applied to fuse adjacent fibers, then fiber fusion is achieved, but thickness variations across the tape width increase

Engineering Contradiction:
Improvefiber bondingVSAvoidthickness consistency
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent applies local quality by ensuring uniform pressure distribution across the entire tape width during compression. The process conditions are optimized so that each local region of the tape experiences identical fusion conditions, resulting in consistent thickness and bonding quality across all areas of the tape, eliminating the thickness variations that typically occur with high pressure compression

Inventive Principle:
Principle #3Local quality

3Shape

If fibers are spread with overlap to enable mechanical fusing, then fiber alignment is achieved, but thickness variations across the tape width are introduced

Engineering Contradiction:
Improvefiber alignmentVSAvoidthickness uniformity
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The patent implements preliminary action by pre-aligning fibers in a unidirectional manner and pre-spreading them to the optimal overlap configuration before the fusing process. This preliminary preparation ensures that when compression is applied, the fibers are already positioned for uniform fusion, preventing thickness variations that would otherwise occur during the fusing process

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by precisely controlling the degree of fiber spread and overlap, as well as the subsequent compression parameters. By optimizing these parameters, the process achieves complete fiber fusion while minimizing thickness variations across the tape width, resolving the contradiction between alignment quality and thickness uniformity

Inventive Principle:
Principle #35Parameter changes

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 resulting tapes demonstrate reduced thickness variations and improved mechanical properties, including tensile strength and modulus, leading to superior performance in antiballistic applications without compromising dimensional characteristics.

Implementation Method 1

compressing the fibers at high pressure and below the melting temperature of the fibers

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

The mechanical fusing of adjacent fibers is carried out by spreading the fibers, such that there is at least some overlap between adjacent fibers, and compressing the fibers at high pressure and below the melting temperature of the fibers

Methodology Applied
Scientific EffectMechanical fusing:

Implementation Method 3

followed by cooling, to produce tapes with a coefficient of variation in thickness across the width of no more than 6%

Methodology Applied
Scientific EffectCooling: Cooling

Data Source

PatentUS10767290B2Tape and products containing the same
Publication Date: 2020.09.08 AVIENT PROTECTIVE MATERIALS BV

AI summary

The invention relates to a fibrous tape comprising fused polymeric fibers, said fibrous tape having a tape thickness and a tape width and being characterized by a coefficient of variation (CV) of the tape thickness across the tape width of at most 6%.