Research on PCM Textiles with Material Properties in Sports Wear. Application 1. Dongmao Ye

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1 Advanced Materials Research Online: ISSN: , Vol. 910, pp doi: / Trans Tech Publications, Switzerland Research on PCM Textiles with Material Properties in Sports Wear Application 1 Dongmao Ye Wuhan Textile University, Physical Education Department Wuhan City, , P.R. China yedm568@126.com Keywords: Phase Change; Phase Change Materials (PCM); Thermostat Textiles; Sports Wear; Temperature. Abstract: A new type of intelligent PCM functional textile has been developed based on intelligent phase change material and advanced textile manufacturing technology. The application of such PCM textile in sports wear can help to enhance athletes performance. This paper analyzes the effects of intelligent PCM textile, characteristics of phase change materials and its preparation methods; discusses the possible effects of intelligent PCM textile to the results of sports events; suggests to make further study and research on phase change material in sports wear application so to develop more PCM sports wear suitable for different sports events. Matter exists in three states: solid, liquid and gas. These three states can convert and change into each other when temperature changes. This conversion process is called Phase Change [1]. Normally thermal absorption or heat releasing are associated with the phase change process. The material which can absorb, store and release energy as latent heat, and change its phase or states at the meantime, is called Phase Change Material (hereinafter refers to PCM). The combination of PCM technology and textile manufacturing technology contributes a new intelligent PCM thermostat textile [2]. Clothing made with this kind of textile is obtained two-way thermal regulating functions. At present, the PCM thermostat textile already becomes the research hotspot of functional textile products both at home and abroad. But, research on its application in sport wear is very few. According to the features of heat releasing and temperature variation in different sports events, the application of such new textile in sport wear is valuable and prospective. 1. Effects of Intelligent PCM Thermostat Textile Based on the phase change features, PCM adapting to human body temperature is introduced into textile during the production process, thus provide to the textile the ability of heat absorption or releasing at a setting temperature [3]. Therefore, when the ambient temperature raises, the PCM in the textile will absorb the heat and change from solid phase to liquid phase, as a result human body surface temperature will be reduced; conversely, when the ambient temperature decreases, PCM will change from liquid phase to solid phase and release heat at the same time, so to increase the temperature and warm up the human body. Within a certain period of time, this special textile can keep the microclimate within clothing at a constant temperature in order to prevent heat stress and maintain human body in a well and comfort condition. Using the intelligent PCM thermostat textile to produce sport wear can effectively protect athletes being harmed from heat peak and hypothermia during or after the sports activities. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-10/05/16,20:25:44)

2 Advanced Materials Research Vol Features of PCM applied in sports wear 1) Suitable phase change temperature. Normally, the PCM with phase change temperature between o C is used to produce sports wear under extreme cold weather; PCM with phase change temperature between o C is used to produce sports wear used in warm weather; PCM with phase change temperature between o C is used to produce sports wear for hot weather or large exercise load. 2) Heat storage capacity. The selected PCM shall either have relatively bigger latent heat capacity, or higher heat storage capacity calculated based on unit mass of the material and unit physical volume. 3) Low volume expansion and less stiffness. If the PCM expands too much or becomes too stiff during the phase change process, the physical properties of sports wear made with this PCM textile will be changed accordingly, which might affect athletes performances. 4) Efficient heat conduction and phase change reversible. The PCM shall melt and cure at relatively constant temperature. The PCM shall be high efficient on heat conduction with rapid heat absorption and releasing speed. 5) Safety, hygiene and reliability. The selected PCM might be daily use and have direct contact with human skin, therefore the chemical properties of the selected PCM shall be very stable without any toxicity. 6) Reusable. Sports wears are not single use commodity. The selected PCM shall be endurable for regular wearing and cleaning. 7) Low cost. The selected PCM shall have reasonable price and cost in order to have a wider range of consumer and a better effect of market promotion. 3. Preparation of intelligent PCM thermostat textile Due to the special requirements of textile used for wearing apparel, the PCM that suitable for this application are very limited, only those that have phase change temperature similar as human body normal temperature can be selected. At the moment, there are two main processes to produce intelligent PCM thermostat textile: fiber spinning process and coating process. 3.1 Fiber spinning process Fiber spinning process is mainly composed of microscopic capsule spinning process, complex spinning process and filled hollow fiber process, etc Microscopic capsule spinning process Microscopic capsule spinning process is one of the most advanced processes to produce phase change fiber. Microscopic capsule containing phase change materials with average diameter 1-5µm will be applied into the spinning solution of polyacrylic fiber. The PCM is evenly distributed in the

3 452 Materials, Manufacturing Engineering and Information Technology fiber so that the fiber obtains excellent heat storage capacity. In 1990s, Outlast Technology (USA) got the patent of microscopic capsule process from Triangle Company. Based on this patent, then they developed heat storage thermostat textile. The fiber fineness already reached 2.2dtex, fully satisfied with the requirements to produce knitted and woven textile. [4] Complex spinning process Phase change material is added into polymer spinning solution. The solution is pumped through spinner to produce fiber. The PCM will then already be planted into the fiber through the process. Now, with this PCM implanted fiber, we can produce sheath-core structure and bilateral structure composite fiber which have heat absorption and releasing abilities. The composite fiber then can be used to spin and weave cloth. Based on this technology, Outlast has already produced PCM thermostat polyacrylonitrile fiber with fineness 2.2dtex, 3.3dtex and 5.0dtex Filled hollow fiber process Before spinning, mini-pcm is filled into the hollow fiber via special process, then the hollow fiber will be coated with resin in order to prevent PCM leakage so to maintain the fiber s thermostat function. Vigo together with his team put mineral salts and water of crystallization into the hollow fiber. When phase change salts melt and crystallize under ambient temperature, the fiber is capable to store and release the phase change heat reversibly, the fiber then become a thermostat fiber. 3.2 Coating process Prepare the mixture solution with the following substances: microscopic capsule with average diameter around 5µm, adhesive, antifoaming agent and dispersant; coat the cloths (textile or nonwovens) with the above mixture solution through heat transfer coating technology; dry the coated cloth under suitable temperature; clean the cloth with soap to remove the un-reacted substances; the cloth then obtains intelligent thermostat function. Harlan and his team made skiwear with this thermostat cloth and tested the skiwear in skiing or skiing similar conditions. The test results approved the thermostat and protection functions of this new kind of skiwear. 82% of the test volunteers were satisfied with its performance of wind proof and heat insulation of the skiwear. [5] 4. Application of intelligent PCM thermostat textile in sports wear 4.1 Affect of intelligent PCM thermostat textile to human sports Intelligent PCM thermostat sports wear can reversibly store and release heat. The PCM sports wear can absorb the excess body heat created during the strenuous exercise. When the exercise stops, PCM will then release the heat to maintain body temperature. By this means, the PCM sports wear can prevent the human body being harmed from over heat or chill. During the exercise, the ratio of body skin temperature rising is closely related to exercising intensity, exercising duration and personal physique. Although the ambient temperature influences a lot to the skin temperature, but the exercising intensity and duration are the key elements that decide the body temperature during the exercise. For example, 10 km skiing racing in extremely cold temperature, a long term and intensive exercise, athletes are covered with very thick cloth which bring difficulties to release body heat, the athlete s axillary temperature might even reach o C. However, if the athletes wear the skiing wear made with PCM thermostat textile, the cloth can

4 Advanced Materials Research Vol actively regulate and control the skin temperature. When skin temperature raises, PCM will absorb the heat and phase change from solid to liquid, reduce the body temperature correspondingly. When the skin temperature decreases, PCM will release the heat, phase change from liquid to solid, protect body temperature at the mean time. PCM thermostat textile can regulate the clothing temperature so to keep a constant microclimate condition at the certain area of human body. Meanwhile, human body is a thermal and moisture radiation object. During the exercise, body will produces great amount of heat, skin will give off sweat to cool the body, and keep constant body temperature. Whereas giving off sweat will increase the interior temperature within the clothes, if the clothes interferes the sweat from quick evaporating, a heat peak will be created underneath the clothes, which is for sure discomfort and might affect athletes performances. Cool-max and Coolplus are functional textiles for moisture absorption and sweat discharging. Therefore, they can be used together with PCM thermostat textile to produce intelligent sports wear which can keep human body stay always in a comfort condition in order to increase the comfortable and pleasant feeling in the sports exercise, and enhance athletes performances. 4.2 The future of PCM thermostat textile application in sports wear At the moment, sports wear made by Outlast, Coolmax blends textile appeared in USA and European market. This kind of sports wear has very excellent thermostat, heat insulation, moisture absorption and sweat discharging properties. In recent years, Shanghai No. 36 Knitwears Factory has made great efforts on researching and development of intelligent thermostat fiber, yards, thermostat fabrics and functional garments, and the following leading products series have been industrialized and put forward to marketing promotion stage: intelligent heat insulation series, sports series, cooling series and multi-functional thermostat series. However, all these special fabrics are mainly used to produce outerwear and underwear, the application in all kinds of sports wear are very few. We shall enhance and promote vigorously the application of intelligent thermostat textile in the field of sport wear Select suitable PCM according to different sports events The sports events can be divided as per following based on different dominant factors of athletic abilities: Physical strength dominated including track, bicycle-track racing, rowing, skiing racing and skating, etc; Skill dominated including gymnastics, ball games, fencing, shooting and archery, etc. The body heat releasing are various as per different events. The key factors of researching are the capability of heat storage, thermal conductivity, hygiene safety and reusability of intelligent thermostat textile, as well as the selection of suitable PCM according to the heat releasing and temperature variation of a certain sports event Select suitable production process for the intelligent PCM textile As for intelligent PCM thermostat textile, the most important thing is the capability of temperature control. The temperature control capability of sports wear differs from different sports events set by summer and winter Olympics. The amount of PCM added in the textile is the essential index of temperature control capability. Further investigation shall be done to find out the best ratio of PCM added in the textile in the production process. Besides, normally sports wear are required to be moisture permeable, sweat discharging, high tear strength, easy cleanable and wear resistant. Although the textile made only with PCM has very good thermostat performance, but the fiber itself is not strength enough, easy to be broken, so it is not suitable for spinning. Whereas if the

5 454 Materials, Manufacturing Engineering and Information Technology Coolmax yarn can be mixed with PCM thermostat fiber at a certain blending ratio, the blended fabric will then have excellent performance of thermostat, moisture absorption and sweat discharging, as well as high tear strength Enhance the study and research on the application of PCM thermostat textile in all kinds of sports events. The environment of different sports events is various and the amount of body heat releasing is also changeable accordingly. Sports events in winter require clothes with better heat insulation property. The clothes must be a certain thickness and multi-layers; while sports events in summer require thin clothes, good effect of cooling, excellent performance of moisture absorption and sweat discharging. It is quite necessary to develop all series of intelligent PCM thermostat sports wear for different sports events. Meanwhile, further study and research on the heat storage and thermostat performance of PCM textile must be carried out and enhanced. Two issues are very important: the range of temperature change and the persistence of phase change process of PCM. These two issues and their influences to the sports event are the most important basis to develop PCM textile and expand its application in wider sports wear. 5. Conclusion As a new type intelligent textile, PCM thermostat textile contains phase change material which can absorb and release heat so to keep human body at a constant temperature. The application of such textile in sports wear will help athletes to create better results and prevent human body being harmed from over-heat or over-cold condition of microclimate within clothing. Therefore, it is very important to study PCM and the preparation process suitable for sports wear, as well as the development of various PCM thermostat sports wear fit to different sports events. Enhance the performance test of such new material and the research of its influences to human sports will greatly help the development of PCM thermostat textile to reach a wider range of application in sports wear. The future of intelligent PCM thermostat textile in this area is prosperous. 1 Wuhan Textile University functional sportswear projects funded research base About the author: Ye-dong Mao, male, born in 1970, professor, master. Research directions for the sports fabric References [1] ZALBA B,MARIN J M,CABEZA L F,et al.review on thermal energy storage with phase change: materials,heat transfer analysis and applications[j].applied Thermal Engineering, 2003, 23: [2] Lan Hong Yan, Fang Lei. Production and Development of Intelligent Thermostat Fiber [J]. Science & Technology of Wool and Linen Shanghai, 2012 (1): 29-32; [3] Han Na, etc. Research and Development of Heat Storage Thermostat Fiber (I) [J]. Fabrics for Industrial Application, 2011 (4): 1-6; [4] Zhan Yi Zhen, Zhu Ping, etc. The Current Situation of PCM Thermostat Textile Application [J], Dyeing & Finishing Technology, 2007 (7): 5-11;

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