Colored UHMW Polyolefin Multifilament Yarns With Rub-Resistant Coating
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Solution Overview
Problem
High tenacity polyolefin fibers, such as those used in multifilament yarns, face challenges in maintaining long-lasting color due to the tendency of colored coatings to come off with vigorous rubbing, necessitating costly pretreatment steps like corona treatment.
Innovation Solution
A method involving coating untwisted multifilament ultrahigh molecular weight polyolefin yarns with a colorant in a thermoplastic resin carrier having a lower melting point than the yarns, followed by heating and stretching without fusing the filaments, to create a colored yarn with improved color-fastness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a colored coating is applied to high tenacity polyolefin yarns, then the yarns gain color, but the color comes off with vigorous rubbing
Solution Approach 1:
The patent changes the physical-chemical parameters of the coating process by heating the coated yarns to temperatures between 80-150°C. This thermal treatment modifies the resin carrier's properties, enabling it to penetrate and bond with the polyolefin filaments, thereby transforming the coating from a surface application to an integrated coloration that resists rubbing
Solution Approach 2:
The heating process induces phase transitions in the resin carrier, transitioning it from a solid or semi-solid state to a molten or softened state that can penetrate the filaments. This phase change enables the colorant to embed within the yarn structure rather than remaining as a superficial coating, solving the color-fastness problem
2Reliability
If plasma spray or corona treatment is applied prior to coloring, then color retention improves, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent extracts and eliminates the complex plasma spray or corona treatment steps from the manufacturing process. Instead, it uses a simpler thermal heating approach combined with a resin carrier system to achieve the same color-fastness result, thereby reducing device complexity and manufacturing cost while maintaining reliability
Solution Approach 2:
The invention employs a disposable resin carrier that is consumed in the process to achieve color bonding. This low-cost, single-use carrier replaces expensive and complex pretreatment equipment, providing an economically viable solution that eliminates the need for costly plasma or corona treatment systems
3Temperature
If the thermoplastic resin has a lower melting point than the filaments, then the coating can be applied and heated without damaging the yarn, but the resin must be carefully selected
Solution Approach 1:
The patent establishes specific parameter ranges for the resin carrier's melting point (lower than the polyolefin filament melting point but within 80-150°C heating range). This parameter specification enables manufacturers to select appropriate resins that facilitate color bonding at controlled temperatures without damaging the high tenacity filaments, balancing ease of manufacture with yarn integrity
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 achieves colored multifilament yarns with enhanced color retention even after vigorous rubbing, eliminating the need for costly pretreatment steps and suitable for demanding applications like ropes and storm curtains.
Implementation Method 1
coating the substantially untwisted multifilament yarn with a coating composition comprising colorant in a thermoplastic resin carrier, the thermoplastic resin having a lower melting point than the filaments of the multifilament yarn
Implementation Method 2
the coating composition being adhered to the filaments of the multifilament yarn
Implementation Method 3
heating the multifilament yarn while stretching the yarn without fusing of the filaments of the multifilament yarn
Implementation Method 4
heating the multifilament yarn while stretching the yarn without fusing of the filaments
Data Source
AI summary
A method of making colored multifilament ultrahigh molecular weight polyolefin yarn, including feeding at least one substantially untwisted multifilament ultrahigh molecular weight polyolefin yarn, coating the substantially untwisted multifilament yarn with a coating composition comprising colorant in a thermoplastic resin carrier, with the coating composition being adhered to the filaments of the multifilament yarn, and heating the multifilament yarn while stretching the yarn without fusing of the filaments of the multifilament yarn. The resultant yarn is a colored multifilament yarn having improved color-fastness. The thermoplastic resin has a lower melting point than the filaments of the multifilament yarn. Preferably, a plurality of the substantially untwisted multifilament ultrahigh molecular weight polyolefin yarns are processed together. Articles formed from the colored multifilament yarns may be prepared and subjected to a heating step to provide a colored surface coating of the thermoplastic resin over the article.