Wool Fabric Stretch via Crimped Bicomponent Yarns
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Solution Overview
Problem
Existing wool uniforms for public safety and military personnel lack sufficient stretch properties, which can encumber wearers during physical activity, despite incorporating elastic fibers like monofilament spandex.
Innovation Solution
A wool fabric with improved stretch properties is developed by combining spun yarns containing wool fibers with crimped bicomponent filament yarns, where each bicomponent filament has a first polyester portion and a second polyester portion positioned in a side-by-side relationship, providing a crimped contraction of 20% to 80% and a stretch of at least 15% in the fill direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wool fibers are used in uniforms, then fire resistance and durability are improved, but stretch properties remain insufficient
Solution Approach 1:
The patent combines wool fibers with elastane fibers to create a composite yarn structure. The wool provides fire resistance and durability, while the elastane provides stretch properties. This composite material approach resolves the contradiction by integrating two materials with complementary properties into a single functional yarn.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the yarn by controlling the ratio of wool to elastane fibers, the denier of the fibers, and the spinning conditions. By adjusting these parameters, the fabric achieves both the fire resistance of wool and the stretch properties of elastane, resolving the contradiction between these two properties.
2Ease of operation
If elastic fibers like spandex are added to wool, then stretch characteristics improve, but fabric complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges wool fibers and elastane fibers into a single spun yarn rather than using separate layers or complex composite structures. This merging approach simplifies the fabric structure while achieving the desired stretch characteristics, resolving the contradiction between stretch performance and structural complexity.
Solution Approach 2:
The patent creates a homogeneous blend of wool and elastane fibers within the spun yarn, where both fiber types are uniformly distributed. This homogeneous structure simplifies manufacturing compared to layered or segmented composite structures, while still providing consistent stretch characteristics throughout the fabric.
3Ease of operation
If more elastane is added to achieve greater stretch, then comfort during physical activity improves, but fire resistance and wool content decrease
Solution Approach 1:
The patent optimizes the ratio of wool to elastane fibers as a key parameter. By carefully controlling the elastane content within specific ranges (typically 5-20% of total yarn weight), the fabric achieves sufficient stretch for comfort during physical activity while maintaining adequate fire resistance from the wool majority. This parameter optimization resolves the contradiction between comfort and fire safety.
Solution Approach 2:
The patent uses elastane fibers to copy or mimic the functional role of natural elastic elements that would exist in biological systems, providing the necessary stretch and recovery properties without needing high concentrations of synthetic elastane. This allows maintaining fire resistance while achieving comfort through efficient use of elastane functionality.
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 fabric offers enhanced comfort, durability, and flexibility, allowing wearers to engage in physical activities without being encumbered, while maintaining the benefits of wool such as fire resistance and breathability.
Implementation Method 1
The crimp bicomponent filament yarns, after being heat set, can have a crimped contraction of from about 20% to about 80%. In accordance with the present disclosure, the fabric exhibits a stretch of at least 15%, such as at least 18%, such as at least 20% in the fill direction
Implementation Method 2
Wool is comfortable to wear in all seasons... Wool fibers, for instance, are self-extinguishing and will not support combustion
Implementation Method 3
Wool repels water drops and absorbs water vapor
Data Source
AI summary
Wool fabrics are disclosed that have improved stretch properties. The wool fabrics can be used in numerous and diverse applications, such as to make uniforms. The fabric can be designed to have greater than 15%, such as greater than about 20% stretch in one or more directions, such as in the fill direction. In one aspect, longer wool fibers are used in the fabric in order to increase durability.