Abstract:
A yarn is provided with a hollow fiber including a plurality of filaments and one or more longitudinal voids between the filaments; and a heat retention fiber being a fiber for emitting infrared light, the heat retention fiber including a plurality of filaments each being capable of retaining heat, the filaments having nanoscale powder capable of emitting near and far infrared light uniformly formed therein. The hollow fiber and the heat retention fiber are twisted together to form a yarn having heat retention capability.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates to yarn and more particularly to a ply yarn having twisted hollow fiber and heat retention fiber suitable for use in the production of thermal clothes. 
         [0003]    2. Description of Related Art 
         [0004]    Typically, a yarn has interlocked fibers without voids. However, such yarns are heavy and poor in heat retention capability. For increasing heat retention capability of clothes, a type of yarn having fibers with voids is commercially available. 
         [0005]    It is understood that heat retention capability of clothes depends on the factors such as fibers, texture, and manufacturing. It is further understood that moisture absorption, air permeability, glitter, heat retention, and radiation due to far infrared light are also under consideration in the production of textiles. 
         [0006]    Clothes made from wool or cotton is good in heat retention. However, such clothes are heavier and may hinder the mobility of a wearer. Moreover, it is not aesthetic. 
         [0007]    There is a type of thermal clothes (e.g., underwear) having far infrared materials as components for heat retention purpose. Further, there is a type of thermal clothes having ceramic with far infrared materials as components. The far infrared materials can emit light having a wavelength of between 4.0 μm and 14 μm. Such clothes are featured with capabilities of heat retention, increasing blood circulation, etc. But its manufacturing cost is relatively expensive and thus less competitive in the market. 
         [0008]    Notwithstanding the prior art, the invention is neither taught nor rendered obvious thereby. 
       SUMMARY OF THE INVENTION 
       [0009]    It is therefore one object of the invention to provide a yarn comprising a hollow fiber including a plurality of filaments and one or more longitudinal voids between the filaments; and a heat retention fiber being a fiber for emitting infrared light, the heat retention fiber including a plurality of filaments each being capable of retaining heat, the filaments having nanoscale powder capable of emitting near and far infrared light uniformly formed therein; wherein the hollow fiber and the heat retention fiber are twisted together to form a ply yarn having heat retention capability. 
         [0010]    The above and other objects, features and advantages of the invention will become apparent from the following detailed description taken with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  schematically depicts a yarn having interlocked hollow fiber and heat retention fiber according to the invention; 
           [0012]      FIG. 2  is a detailed view of the area of circle B in  FIG. 1 ; and 
           [0013]      FIG. 3  is a sectional view taken along line A-A of  FIG. 1 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0014]    Referring to  FIGS. 1 to 3 , a yarn  30  comprising a hollow fiber  10  and a heat retention fiber  20  in accordance with the invention is discussed in detail below. 
         [0015]    The hollow fiber  10  comprises a plurality of filaments  11 . The hollow fiber  10  further comprises one or more longitudinal voids between the filaments  11 . The voids occupy at least 15 percent (15%) of the cross sectional area of the hollow fiber  10 . The hollow fiber  10  is 75d/50f. That is, the filament  11  is 75 denier and there are 50 filaments  11 . Note: f represents number of uniform filaments and denier (or den) is a unit of measure for the linear mass density of fibers. It is defined as the mass in grams per 9,000 meters. The denier is based on a natural standard, i.e., a single strand of silk is approximately one denier. A 9,000-meter strand of silk weighs about one gram. Preferably, the filaments  11  of the hollow fiber  10  are in the range from 50d to 150d. 
         [0016]    The heat retention fiber  20  comprises a plurality of filaments  21  having heat retention capability. Preferably, the filaments  21  are made of fibers and nanomaterials capable of emitting near and far infrared light. The nanomaterials are ceramic or metal oxides having a diameter D90 equal to or less than 350 nm. The nanomaterials are adhered to the fibers by a process of dispersion. The heat retention fiber  20  thus has the capabilities of absorbing near infrared light emitted from the sun for retaining body heat, and emitting far infrared light having a wavelength of between 4.0 μm and 14 μm so as to undergo a harmonic motion with the body, increasing the blood circulation, and increasing the body temperature to a predetermined value. Preferably, the filaments  21  of the heat retention fiber  20  are in the range from 50d to 150d. 
         [0017]    The filaments  11 ,  21  are selected from the group consisting of polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polytrimethylene terephthalate (PTT), acrylic fiber, rayon, nylon, and polypropylene (PP). 
         [0018]    As shown in  FIG. 1 , the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20  are formed by extruding. Next, a fully drawn yarn (FDY) device  100  is activated to draw the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20 . Next, an air-textured yarn (ATY) device  200  is activated to air texturize the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20  so as to twist them to finish a ply yarn  30  having heat retention capability. The hollow fiber  10  has a contraction ratio of 5% and the heat retention fiber  20  has a contraction ratio of 15%. In detail, the ATY device  200  employs a process of air texturizing the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20  in order to twist them in an irregular pattern as shown. Further, the ply yarn  30  has a fluffy surface. Furthermore, the ply yarn  30  is heated to obtain its finals shape. As shown in  FIG. 2 , the ply yarn  30  has a plurality of fluffs  31  on its outer surface. The fluffs  31  can give a fluffy feeling to the hand touching a textile product (e.g., clothes) made from the ply yarns  30 . It is noted that the irregular pattern of the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20  is for illustration only. 
         [0019]    Preferably, the textile product made from the ply yarns  30  has less than 220 gram/yard which is much less than the conventional thermal clothes which have about 350-550 gram/yard. Thus, the invention is light weight, has heat retention capability, and is cost effective. 
         [0020]    The process of air texturizing the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20  by the ATY device  20  involves the following conditions: Air texturizing speed 400-550 meter/minute, air injection pressure 8-10 kg/cm 2 , fiber strength greater than 2.5 gram/d (ASTM D3822), and fiber boiling water contraction ratio less than 6.0% (ASTM D3822). 
         [0021]    The invention has the following characteristics: The heat retention fiber  20  has the capability of retaining heat by uniformly permeating infrared heat absorbing and radiating powder of near and far infrared light into fiber molecules. Therefore, it is possible of greatly absorbing near infrared light emitted from the sun, i.e., absorption rate increase. Further, the powder can absorb heat from near infrared light emitted by the sun in order to retain the body heat. Furthermore, the absorbed far infrared light can undergo a harmonic motion with the body so as to increase the blood circulation, increase the body temperature to a predetermined value, and bring about the heat retention effect. In addition, the invention employs a process of air texturizing the filaments  11  of the hollow fiber  10  and the filaments  21  of the heat retention fiber  20  in order to twist them and form a heat transfer prevention layer for heat retention purpose. Finally, the yarns are undergone a process of dying to eliminate undesired color and obtain a fluffy outlook. 
         [0022]    For the ply yarn  30  having the heat retention capability, it is preferred that the hollow fiber  10  has a weight fraction of 25-75% and the heat retention fiber  20  has a weight fraction of 75-25%. Preferably, the ply yarn  30  is in the range from 50d to 300d and number of uniform filaments (i.e., f) is 48 to 578. 
         [0023]    A textile product made from the yarns of the invention has the following characteristics: Infrared light emission rate equal to or greater than 80%, near infrared light absorption rate equal to or greater than 65%, temperature increase equal to or greater than 5° C. (at a thermovision test environment of temperature: 25±0.5° C. and humidity: 65±5% RH), and a heat retention coefficient per unit area equal to or greater than 0.4. 
         [0024]    It is envisaged by the invention that the yarn having interlocked hollow fiber and heat retention fiber has the following advantages: 
         [0025]    There are increased voids in the yarn with more space being occupied. The effects of absorbing heat from near infrared light emitted by the sun and heat retained by the heat transfer prevention layer of the hollow fiber can be brought about for greatly increasing the heat retention capability. 
         [0026]    Weight of a textile product made from the yarns can be decreased to less than 200 gram/yard. Thus, it is light weight, comfortable, and cost effective. 
         [0027]    Heat retention by uniformly permeating infrared heat absorbing and radiating powder of near and far infrared light into fiber molecules is made possible. Therefore, it is capable of greatly absorbing near infrared light emitted from the sun, i.e., absorption rate increase. Further, the powder can absorb heat from near infrared light emitted by the sun in order to retain the body heat. Furthermore, the absorbed far infrared light can increase the blood circulation, increase the body temperature to a predetermined value, and bring about the heat retention effect. 
         [0028]    The hollow fiber can prevent heat from transferring due to its hollow structure. Thus, temperature of the body of a wearer is still maintained at a normal value even in a cold winter. 
         [0029]    While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modifications within the spirit and scope of the appended claims.