Polyamide fiber with improved comfort management, process thereof and article made therefrom

Abstract

The present invention relates to a polyamide fiber with improved comfort management properties. The present invention also discloses a method for obtaining such fiber and articles made therefrom. The polyamide fiber is produced from a hygroscopic polyamide in a multilobal cross section profile. The hygroscopic polyamide fiber is produced preferably from polyamide 5.X, X being an integer from 4 to 16. Most preferably polyamide 5.6, which is a biobased polyamide obtained from pentamethylenediamine and is derived from sugar-based renewable feedstocks. The present invention thus discloses a polyamide fiber and articles made therefrom for sportswear and leisurewear applications, with improved water absorption, wicking and drying properties, wherein the sweat is transported away from the skin and is quickly dried, thereby reducing the wet sensation and chill during activity. The present invention provides freshness and comfort by maintaining a pleasant skin temperature and microclimate.

Description

[0001]The present invention relates to a polyamide fiber with improved comfort management properties. The present invention also discloses a method for obtaining such fiber and articles made therefrom. The polyamide fiber is produced from a hygroscopic polyamide in a multilobal cross section profile. The hygroscopic polyamide fiber is produced preferably from polyamide 5.X, X being an integer from 4 to 16. Most preferably polyamide 5.6, which is a biobased polyamide obtained from pentamethylenediamine and is derived from sugar-based renewable feedstocks. The present invention thus discloses a polyamide fiber and articles made therefrom for sportswear and leisurewear applications, with improved water absorption, wicking and drying properties, wherein the sweat is transported away from the skin and is quickly dried, thereby reducing the wet sensation and chill during activity. The present invention provides freshness and comfort by maintaining a pleasant skin temperature and microclim...

AI Technical Summary

Benefits of technology

[0108]The cross section profile of the present invention improves handle and softness of the fiber because of the lower flexural rigidity due to the irregular and preferred bending direction, as opposite to the resilient behavior of round and trilobal cross section. Similar phenomenon is observed in the “bean” shape cross section of cotton fiber.

[0109]Wear comfort is a complex phenomenon but in general it can be divided into four different main aspects: a) Thermophysiological wear comfort influences a person's thermoregulation, it comprises heat and moisture transport processes through the clothing. Key notions include thermal insulation, breathability and moisture management; b) Skin sensorial wear comfort characterizes the mechanical sensations that a textile causes at direct contact with the skin, pleasant perceptions include smoothness and softness, whereas unpleasant would be scratchy, too stiff, or clings to sweat-wetted skin; c) Ergonomic wear comfort deals with the fit of the clothing and the freedom of movement it allows. It is mainly dependent on the garment's pattern and the elasticity of the materials; d) Psychological wear comfort is affected by fashion, personal preferences, ideology etc.

[0110]Thermophysiological comfort is based on the principle of energy conservation. All the energy produced within the body by metabolism, has to be dissipated in exactly the same amount from the body, by the respiratory heat loss (breathing), the dry heatflux comprising radiation, conduction, convection, and the evaporative heatflow caused by sweating. If more energy is produced than dissipated, the body suffers from hyperthermia. And too high a heat loss leads to hypothermia.

[0111]Wear comfort is never the consequence of only one single parameter; instead it is a result of fiber composition, fabric structure, clothing layering system, chemical finishing and so forth. Several research studies have proven that fabric constructional parameters and chemical finishing are as important as fiber composition. For instance, lightweight, porous and thin fabrics are desirable for sports textiles, in addition to hydrophilic and quick-drying properties. The water vapor is diffused through the inter-yarn spaces, through inter-fiber spaces, through the fiber substance itself, and through the free air spaces within textiles.

[0112]Chemical finishing includes mainly hydrophilic topic treatments and is intended to increase the hydrophilic behavior of hydrophobic textiles. The drawback of chemical finishing is the fact that it is a non-durable treatment and may last a few home-washing cycles only, whereas fibers with intrinsic moisture management properties last the entire life time of the textile article.

[0113]Regarding the yarn composition, the use of filament yarns leads to too smooth and flat textile surfaces directly at the skin. This structure shows too many contact points with the skin, and the fabric is perceived as too smooth and clinging to sweat-wetted skin. Flat filament yarns provide poor skin sensorial perception, whereas spun yarns or textured yarns provide better skin sensation. Textured yarns provide less contact points with the skin and higher insulation, softness and pleasant touch. Protruding fiber ends are generated, as well as a more 3D structure, in spun yarns and textured yarns, which act as spacers between skin and textile. Yarn cross section with grooves, pores and capillarity channels along the filament are also important to increase the wicking speed and surface area, what leads to wicking and faster drying rate.

Problems solved by technology

Absorption reduces skin humidity and retains relative comfort in moderate activities with limited sweating, whereas in higher metabolic activities and intensive sweating, the moisture may remain in the clothing system and may be detrimental to heat balance at a later stage as wetting of clothing reduces the effective thermal insulation, what reduces the comfort and causes the post-chilling effect after cessation of the activity.

Highly hygroscopic fibers also lead to a physiologically problematic lengthening of the drying time.

If the drying time becomes too long, the post-exercise chill is unavoidable, as the sweat wetted shirt loses its thermal insulation.

In addition, wet skin may cause skin irritations or even moisture-generated dermatoses.

Moisture absorbed in garments gradually reduces thermal insulation.

When activity drops and sweating ceases, the drying of wet clothing layers may deprive the body of more heat than is generated by metabolic rate, the results is a post-exercise chilling effect that may endanger heat balance and result in hypothermia.

If the hydrophilicity is too high, as in the case of natural fibers, the drying rate may be delayed as water is absorbed and retained inside the fiber for longer periods.

A poor wicking may also lead to saturated regions and reduced transport and drying rates.

This approach requires bi-component equipment and the drying rate and wicking speed are not provided.

Disadvantages of this approach include lack of fast drying rate, water absorption and wicking speed.

The cooling mechanism may also lead to uncomfortable sensation during active sweating, such as hypothermia due to excessive cooling.

A drawback of the use of PVP is the fact that the occurrence of pyrrolidone as a by-product tend to causes fiber yellowing, thereby affecting the desired mechanical and chemical properties for textile applications.

In addition, the fast wicking and drying behavior are not demonstrated and could cause discomfort during excessive sweating and sports activities.

For instance, the trilobal profile (also known as Y) is well known and widely used for providing luster and brightness to the article; however, it does not increase capillarity, softness and surface area, as they do not provide deep micro-channels.

JP5206640 discloses a modified cross section polyamide with radial lobes; however, water absorption, wicking and drying rate are not assessed or improved.

A disadvantage of this cross section is the fact that a flat fiber profile leads to more skin coverage, lower insulation, less entrapped air and more contact points with the skin what may reduce the skin sensorial wear comfort.

It does not offer capillarity and does not increase wicking speed and drying rate, hence not being suitable for high sweating activity.

In addition, the flat cross section evaluated in the experiments of the present invention has shown poor processing behavior, what suggests that a flat cross section may be more difficult to be processed by melt-spinning.

Hence, patent number EP 2554721 does not offer a solution for comfort management of sportswear textiles, where wicking and higher drying rates are desired.

There is still no existing fiber in the market that offers at the same time hydrophilic properties, cooling effect, and wicking.

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