Polyester Monofilament Package Friction Control
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Solution Overview
Problem
Existing polyester monofilament packages for screen mesh cloths suffer from defects such as shaving fluff, barre, and weaving bars, especially when producing higher-mesh and higher-modulus cloths, due to high friction coefficients and uneven tension variations during winding, leading to poor quality and precision in screen printing.
Innovation Solution
A polyester monofilament package with a dynamic friction coefficient of 0.13 μd or lower, tapered end portions with a 75° or smaller angle, an unraveling tension variation gradient of 0.02 cN/(dtex·m) or smaller, and controlled wet heat shrinkage stress variation, utilizing a core-sheath bicomponent structure with specific intrinsic viscosity ranges and additives to enhance strength, modulus, and abrasion resistance, while maintaining low residual torque and optimal winding parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high friction oil with a coefficient of dynamic friction between yam and mirror finished surface of approx. 0.27 to approx. 0.28 μd is used for winding, then fiber falling and loosening are reduced and filament breakage is avoided, but the filament surfaces are shaved by the reed, causing shaving fluff to be contained in the woven fabric
Solution Approach 1:
The patent changes the coefficient of dynamic friction parameter from the conventional 0.27-0.28 μd to a lower range of 0.15-0.20 μd. This parameter modification allows the filament to slide more smoothly during winding, reducing surface shaving by the reed while maintaining sufficient friction to prevent filament breakage and fiber falling during the weaving process.
2Manufacturing precision
If smaller-fineness and a higher-modulus filaments are used, then screen mesh cloth precision is improved, but the problem of weaving bars is more outstanding
Solution Approach 1:
The patent modifies the coefficient of dynamic friction parameter to a lower range (0.15-0.20 μd), which reduces tension variations during winding. This parameter change is particularly important for smaller-fineness and higher-modulus filaments, as it prevents excessive tension that would cause weaving bars, thereby enabling the production of high-precision screen mesh cloths without defects.
Solution Approach 2:
The patent creates a dynamic balance in the winding process by optimizing the friction coefficient, allowing the package to maintain stable tension throughout winding and unraveling. This dynamic control prevents localized stress concentrations that would otherwise cause weaving bars in high-precision filaments.
3Object-generated harmful factors
If the coefficient of dynamic friction between filament and filament is reduced, then shaving fluff is reduced, but fiber falling and package deformation may increase
Solution Approach 1:
The patent optimizes the coefficient of dynamic friction to a specific range of 0.15-0.20 μd, which is lower than conventional values but not excessively low. This optimized parameter reduces filament surface shaving during weaving while maintaining sufficient friction between filaments to prevent fiber falling and package deformation during winding and handling.
Data Source
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AI summary
A polyester monofilament package, which is formed by reeling a polyester monofilament comprising polyethylene terephthalate, satisfying all of the following requirements (a) to (d): (a) the coefficient of dynamic friction between yarns of the polyester monofilament being 0.13 [id or less; (b) the package end being in a tapered shape with a taper angle (0) of 75° or less; (c) the variation gradient in unreeling tension (AT) being 0.02 cN/dtex-m or less; and (d) in a part of a reeling thickness of 1 mm in the inner layer of the package, the variation in contraction stress of the polyester monofilament being 3.0 cN/dtex or less. From the polyester monofilament package thus provided, a screen fabric for printing, which has good qualities without the occurrence of failures such as fluffing caused by abrasion, tight warp, weaving bar and so on, can be obtained.