Spacer Fabrics Utilized in Active Wear

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Spacer Fabrics Utilized in Active Wear
TT553-Formation and Structure of Woven and Knitted Fabrics
Spring 2009
Dr. Seyam
04/15/2009
Jennifer Woodson
Introduction
Currently, spacer fabrics, also referred to as 3D fabrics, are being utilized in a myriad of
applications varying from mattresses to seat cushions to automotive applications to activewear to
extreme sporting apparel to intimate wear. Spacer fabrics have several attributes that make them
ideal for a variety of uses including strength, insulation, breathability, and durability. In this
paper the utilization of spacer fabrics in activewear will be investigated and discussed.
Currently, research in this area is limited; therefore recommendations will be made in regard to
where future research can be conducted throughout this paper.
What are Spacer Fabrics
Spacer fabrics (Figure 1) are knitted fabrics that have two, usually warp-knitted, faces
and a pile, of varying thickness, between the two faces. Although spacer fabrics are more
commonly found as warp knits they can also be produced as weft knits. Each face, and the
spacer section, of spacer fabrics are knit from different yarns (Reisfeld, 2002). A method of
production, which has been greatly utilized in the upholstery and automotive markets, is to cut
down the middle of the spacer portion (across the width) of a spacer fabric; this is how many
common pile fabrics, such as velvet, are produced. It was not until the 1980s that spacer fabrics
began to receive recognition for their superior properties, and thus expanded into other markets,
such as athletic apparel and outerwear (Reisfeld, 2002).
Figure 1: Spacer fabrics of varying thicknesses
Source: Fisher, G. (2003). Knitters establish technical niches. Knitting International, 110(1304),
34.
Why are Spacer Fabrics Important
Spacer fabrics are currently being used to replace such fabrics as polyurethane, neoprene,
and other foam type products that are generally laminated, and utilized in end products that
require flexible or bulky type characteristics in order to achieve the desirable outcomes. Spacer
fabrics have properties such as breathability and thermal regulation that are far superior to that of
foam and foam type products. The end uses generally require that these materials are able to
withstand the test of time in regard to constant compression (Anand, 2003). Examples of
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instances where these textiles are utilized include, but are not limited to, seat cushions,
mattresses, geotextiles, bras, activewear, and outerwear. The foams used in these applications
are usually flammable, and are considered to be rather uncomfortable due to the lack of
breathability. Foams also tend to degrade and deform over time with continued use, and cannot
withstand continuous home laundering. In contrast, spacer fabrics are recyclable, which makes
them much more environmentally friendly than foam. Spacer fabrics also breathe well, have
lower moisture absorption, and have superior compression and recovery properties to that of
foams, and can withstand continued home launderings.
Types of Spacer Fabrics: Construction
3-D spacer fabrics that are constructed with a warp knitting machine have two fabric
faces that are produced separately, and are usually about 0.4mm to 1 mm thick. The two faces
are joined via the spacer yarns which, with machine adjustments, can join the two faces directly
or create a space of varying width ranging typically from 1mm to 15mm thick, though
significantly larger thicknesses (i.e. 60mm) are possible (Anand, 2003). The two faces can be
constructed differently, for example one side having a rib structure, or the two faces can have the
same structure. Also, the face fabrics can have different elasticity ratings, can have a solid or net
structure, and can have different textures than one another. Channels can be formed between the
faces for the insertion of tubes, wires, or heating elements depending on the application.
In regard to fibers, any fiber type can be utilized to produce spacer fabrics, though it will
be the end use that dictates what fiber is necessary. A yarn utilized in the spacer area that is of a
higher count will provide more stability to the fabric, whereas a fabric that utilizes yarns of a
finer count will be more pliable, but less stable (Spacer fabrics for medical applications, 1998).
Theoretically, the front face, back face, and pile yarns can all be composed of different fibers/
yarns. Monofilament yarns can offer greater fabric stability or stiffness, although this attribute
may not be necessary or desired is some applications.
When looking at the knitting machinery (Figures 2 & 3), guide bars 1 and 2 utilize the
front needle bar and produce one face of the fabric. Guide bars 5 and 6 utilize the back needle
and produce the other face fabric. Guide bars 3 and 4 carry the spacer yarn which knits, with
both needles, on both faces of the fabric. It is the distance between the two needle bars that will
determine the thickness of the final fabric (Roye, Gries, 2006; Anand, 2003).
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Figure 2: Schematic view of warp knitted spacer Figure 3: Structure of warp knitted spacer
fabrics
fabric
Source: Roye, A. (2004). Spacer fabrics for thin Source: Anand, S. C. (2003). Proceedings
walled concrete elements.
from ISTEK 2003: Recent advances in
knitting technology and knitted structures
for technical textiles applications.
Spacer fabrics can also be produced on a circular double jersey machine or on a flat
machine that is controlled electronically so as to produce weft knitted spacer fabrics (Figure 4).
Producing fabric on the circular knitting machine allows for short runs to be economically
produced, which is ideal for fashion items (Kunde, 2004). Fabrics produced in this way tend to
be denser, and thus heavier, than warp knitted spacer fabrics.
In regard to appearance, spacer fabrics can be constructed in a many ways with varying
fibers being utilized; different elongation and stretch properties, and even different patterns can
be produced on the face fabric with the use of a piezo jacquard mechanism (Karl Mayer
machines). This mechanism will allow for the production of jacquard patterns on the face sides
of spacer fabrics (Figure 5 a & b) (Anand, 2003).
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Figure 4: Weft knitted spacer fabric
Source: Anand, S. Spacers—at the technical frontier. (2003). Knitting International,
110(1305), 39
Figure 5 a & b: Jacquard face spacer fabrics
Source a: http://www.anhuisilk.cn/sandwich.htm
Source b: http://www.inteletex.com/FeatureDetail.asp?NewsId=3417
.
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According to Anand (Anand, 2003), “an ideal ‘dynamic’ or ‘responsive’ fabric is a
combination of a) the right combination of fibers; b) using the right fabric structure; and c) using
the right chemicals or finishes on the fabric.” Spacer fabrics are ideal for activewear in that they
excel in their breathability, wicking, and insulation capabilities (Figure 6). Spacer fabrics will
not degrade in any way during home laundering, and exhibit the ability to release soil easily
during laundering, and detergents can be easily rinsed off. These characteristics are ideal for the
average consumer’s lifestyle as there are no special laundering requirements.
Figure 6: Flow of air and moisture through a spacer fabric
Source: Breathing room. (2002). Retrieved from
http://www.inteletex.com/FeatureDetail.asp?PubID=27&NewsId=191.
Fiber selection is very important when determining the comfort level of the wearer, and
optimizing the beneficial properties noted above. For example, if cellulosic fibers, which are
hydrophilic, are utilized in the face of the fabric touching the skin, the fibers will hold moisture
and will not wick it away quickly, heat transport will then be inhibited, thus leaving the wearer
damp and uncomfortable.
As spacer fabrics have endless options in regard to potential fiber usage, one option is to
use a synthetic fiber on the face side touching the skin, this will aid in pulling moisture away
from the skin. A fiber that conducts moisture can act as a diffuser and thus be used as the pile,
and a natural fiber can be utilized as the face not touching the skin, which will help bring the
moisture to the surface of the fabric and allow it to evaporate (Önal, 2004). This fiber
configuration will help maintain the body’s microclimate whilst the wearer is physically active
and exerting energy.
While fiber selection is important, how the fibers are actually utilized is another
important consideration. Research at the University of Leeds found that by hydroentangling a
thin layer of wool on one side of a spacer fabric, the thermal conductivity of the fabric is reduced
and the thermal resistance is increased (Mao & Russell, 2007). This novel fiber configuration
would keep the wearer warmer by blocking the small holes in the face of the knit fabric.
Blocking these apertures may inhibit the inherent breathability characteristics of spacer fabrics,
and thus may deter one from purchasing a garment made from the fabric. Further research in
regard to comfort and breathability is necessary to determine the perceived consumer value of
such a fabric.
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Exploring Spacer Fabrics in Activewear
Spacer fabrics can be utilized in a variety of athletic activities such as SCUBA diving,
skiing, and snowboarding. Found in jackets, shoes, and protective accessories such as helmets
and knee pads, spacer fabrics offer thermal insulation, impact protection, and breathability in the
application in which they are utilized. Sports and other activities where spacer fabrics may be
useful include: skiing, snowboarding, SCUBA diving, surfing, angling, cricket, cycling, hockey,
rugby, trekking, equestrian, roller/ ice skating, and paddle sports (i.e. Kayaking, Whitewater
Rafting). This is by no means an exhaustive list, as there are many other activities where spacer
fabrics can be utilized.
Desirable Properties in Activewear
The comfort of a garment is not just determined by how it feels while being worn
(sensorial comfort), but psychological comfort—or thermophysiological comfort. This is the
thermoregulation and moisture management provided by the garment/ fabric which aims to keep
the body’s temperature and moisture output, as close as possible to the normal level regardless of
the person’s current physical activity or the current weather conditions. How the garment
actually fits on the body must also be considered in order to determine overall garment comfort.
While each segment of the active apparel industry has different needs or requirements in regard
to comfort, several of the most important factors, that should be considered when determining
garment comfort for athletic apparel, include: Waterproof / water resistant, breathability,
moisture wicking, windproof, odor control, warmth / insulation, light weight, fashionable, tactile
qualities, abrasion resistance, anti-static, protection, versatility, non-constrictive/ freedom of
movement/ does not inhibit vision, and durability.
Spacer Fabric Properties that Correspond to Desirable Properties in
Activewear
The Need for Spacer Fabrics in Activewear
When a person is exerting energy during physical activity, it is important that the microclimate, the climate around the person’s body, stay constant. Spacer fabrics, in the pile portion
of the fabric, have the inherent ability to trap and hold air, and therefore insulate the body. This,
along with the ability to wick away moisture, maintains the body’s microclimate, and thus keeps
the person dry and comfortable. There are many outdoor/ active apparel manufacturers who still
employ the layering concept in order to achieve all the desirable properties in active apparel.
According to Canadian Apparel Magazine (Building performance into outdoor wear, 2002) the
outermost layer should protect the wearer from environmental elements such as wind, rain, or
snow, the middle layer should provide the wearer with warmth, and the innermost layer should
have an insulating factor and have the capabilities to wick moisture away from the skin; it is also
noted that all layers should be breathable and should have wicking capabilities in order to
provide the most comfort to the wearer (Building performance into outdoor wear, 2002). Three
layers of outerwear could create a bulky, cumbersome outfit. Spacer fabrics can accomplish all
of these desirable characteristics in one garment, instead of three.
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The thermal insulation properties of both warp and weft knit spacer fabrics are excellent
when being considered for activewear. A lower density in the pile yarns of the spacer fabrics will
yield a higher thermal resistance which is ideal for activewear fabrics as it will keep the wearer
warm (Pause, 2002). Warp knitted spacer fabrics tend to have a higher thermal insulation value
than weft knitted spacer fabrics regardless to whether the fabric is wet or dry, an important
feature for those who may utilize this fabric in the snow. Warp knitted spacer fabrics also have a
higher thermal absorptivity value than weft knitted spacer fabrics, and thus the warp knitted will
be warmer to touch than weft knitted (Anand, 2003). Yip and Ng found that warp knit spacer
fabrics have a lower thermal conductivity rating than the weft knit fabric, which means the
excess heat from the body would not be as quickly transferred if a warp knit spacer fabric is
being utilized than if a weft knit fabric is to be utilized (Yip & Ng, 2008).
Spacer fabrics that have a rib construction, and are flocked during the finishing process,
have shown to provide better insulation, and better heat and moisture transference, both of which
will help maintain the body’s microclimate (Krel, et al., 2005). The ribs of the face fabrics are
what actually aid in the movement of heat and moisture; the channels created by ribbed fabric
faces thus are better suited to control the microclimate and keep the wearer cool and dry.
In regard to the water vapor permeability properties of spacer fabrics, weft knitted spacer
fabrics have been found to have better evaporative heat loss properties and water vapor
permeability properties than warp knitted spacer fabrics, thus making the weft knit more
comfortable when worn close to the skin of a person who is exerting energy and perspiring
(Anand, 2003). When choosing a fiber type to aid in microclimate regulation, viscose can absorb
the perspiration of the wearer “and delay the moment at which the air in the spacer zone becomes
saturated with moisture” (Machova, Hoffmann, & Cherif, 2007). This means that a person who
is perspiring heavily, or has varying perspiration levels with high peaks, will remain drier for a
longer period of time, and have a more level microclimate, if wearing a garment utilizing spacer
fabrics with a viscose inserted weft yarn. An inserted weft yarn, that is hydrophobic, will
maintain the body’s microclimate more effectively than an inserted weft yarn that is hydrophilic
because the hydrophilic yarn will hold the moisture and inhibit it from being transported away
from the body (Machova, Hoffmann, & Cherif, 2006).
Air permeability is another important factor that should be taken into account when
choosing fabrics for activewear. In this regard, weft knitted spacer fabrics have significantly
better air permeability ratings, and are thus more able to resist air penetration, than the warp knit
fabric (Yip & Ng, 2008). Although, it should be noted that the density of the fabric, regardless
of whether it is a warp knit or a weft knit will have a substantial impact on the air permeability
and thermal regulation properties. A spacer fabric that is quite dense will have a higher thermal
conductivity value, but a low air permeability value; therefore end use must be taken into
consideration to find an optimum density for the fabric.
In regard to breathability, moisture wicking, and insulation of spacer fabrics, research at
the Institute for Textile and Clothing Technology at the Hohenstein Institutes was conducted in
regard to the insertion of a hydrophilic weft yarn on the face of the spacer fabric that is closest to
the body, and its effect on the body’s microclimate. Using a spacer fabric made of polyester
(PES), monofilament for the pile and multifilament for the faces, and various inserted weft yarns,
which accounted for about 5% of the total fabric, in the face of the fabric closest to the body,
which also had a ribbed construction Machova, Hoffmann, and Cherif found that the inserted
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weft yarns increased the density of the fabric, and thus lowered the air permeability. It was also
found that viscose weft yarns increase heat transport by 14.2% when compared to spacer fabrics
without inserted weft yarns. The inserted weft yarn, while increasing the thermal insulation
properties of the fabric, also can increase the dimension stability of the fabric (Reisfeld, 2002).
Another, not commonly realized, important factor of spacer fabrics for certain types of
activewear is compressibility. Many outdoor activities of athletes are seasonal (i.e. skiing),
therefore during the off-season it is likely that the garments are stored away in containers, or
other means, where they under a heavy load. During the in season, these garments are packed in
suitcases for traveling. The athlete or outdoor enthusiast expects the garments to not be distorted
in any way when they are removed from storage, as they should be ready to be utilized for the
new season. Spacer fabrics are very resilient and will resist and recover from pressure that may
be applied on them (Figure 7), thus deformation is not a problem in apparel made using spacer
fabrics and this may increase the life of the garment.
Compression properties of spacer fabrics are highly reliant on the how thick the actual
fabric is and how the spacer yarns are oriented within the fabric. The actual compression
resistance can be controlled via the machinery and the fibers/ yarns being utilized (Anand, 2003).
When spacer yarns are positioned in a “V” shape between the two fabric faces, the final fabric
will have better compression resilience than if the spacer yarns are perpendicular to the fabric
faces (Yip & Ng, 2008). When the angle of the spacer yarns are set at a larger angle, θ (all other
variables constant), they are better able to resist compression than fabrics with spacer yarns set at
a smaller angle (Figure 8).The actual angle of the spacer yarn in the fabric can be calculated with
the following formula (Yip & Ng, 2008):
Where: L= thickness of spacer fabric
W= segment width
Since the compression capabilities of a spacer fabric are largely determined by the
structure of the spacer area, when considering the compression properties of spacer fabrics that
utilize a monofilament as the spacer yarn will have slightly better compression and recovery
capabilities than those that utilize multifilament spacer yarns (Yip & Ng, 2008).
Yip and Ng (Yip & Ng, 2008) found the bending rigidity of the fabric to be dependent on
how the fabric is constructed. For example, warp knitted fabrics have better bending rigidity in
the warp direction and vice versa. Fabric density will also affect the bending rigidity of the final
fabric (Yip & Ng, 2008). The ability for a spacer fabric to stretch is directly related to how the
fabric is constructed, either as a warp knit or a weft knit. Therefore, the ability of the fabric to
stretch will depend on how well the warp or weft knit face fabrics stretch, and the stretchability
of the fiber/ yarn type, as multifilament yarns will be able to stretch more than monofilament
yarns (Yip & Ng, 2008).
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Figure 7: Compression of spacer fabrics
Source: Anand, S. C. (2003). Proceedings from ISTEK 2003: Recent advances in knitting
technology and knitted structures for technical textiles applications.
Warp Knit
Θ=52.33°
Weft Knit
Θ=79.49°
Weft Knit
Θ=78.07°
Weft Knit
Θ=63.43°
Weft Knit
Θ=61.08°
Figure 8: Various spacer fabric construction, fiber/ yarn types, and views
Source: Yip, J., & Ng, S. (2008). Study of three-dimensional spacer fabrics: Physical and
mechanical properties. Journal of Materials Processing Technology, 206(1-3), 359.
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Comparing Conventional Activewear Fabrics to Spacer Fabrics
A study conducted by Anand (Anand, 2003), using 100% polyester yarns in both warp
and weft knitted spacer fabric samples, provides insight into the different properties of warp knit
spacer fabrics and weft knit spacer fabrics (actual values in Appendix I). The warp knitted and
weft knitted spacer fabrics were found to have significantly better tenacity, breaking extension,
and initial modulus than current technical fabrics used today. Although the weft knitted fabrics
will not lose as much heat as the warp knitted fabrics, they are not as well able to absorb and
wick away moisture as the warp knitted spacer fabrics. This could be due partly to warp knitted
spacer fabrics having more bulk than weft knitted spacer fabrics. This aspect is very important
in regard to comfort of the wearer, as it will affect the how well the body’s microclimate is
maintained, and is thus directly related to wearer comfort. Figure 9 provides a concise
comparison of the properties of warp and weft knitted spacer fabrics.
When compared to Sportwool™, a fabric utilized in athletic uniforms, spacer fabrics
have notable superior qualities in regard to thermal insulation, thermal absorptivity, and moisture
wicking. The Sportwool™ fabric performed better than the spacer fabrics in regard to
evaporative heat loss and water vapor permeability, these are two very important properties to
consider when taking comfort into account. The Sportwool™, will allow a wearer to feel cooler
and drier than either of the spacer fabrics, when participating in high energy sports, such as
soccer, where the wearer will likely perspire a great deal. All three fabrics had similar moisture
absorption properties. Figure 9 provides a comparison of all three fabrics (warp knitted, weft
knitted, and Sportwool™).
Property
Superior Fabric
Superior Fabric
(Warp or Weft knit)
(Warp Knit, Weft Knit, or Sportwool™)
Thermal Insulation
Warp
Warp or Weft
Thermal Absorptivity
Warp
Warp or Weft
Evaporative Heat Loss
Weft
Sportwool™
Water Vapor Permeability
Weft
Sportwool™
Moisture Absorption
Warp
All Are Similar
Moisture Wicking
Warp
Warp
Figure 9: Comparison of the properties of warp and weft knitted spacer fabrics
When compared to fleece, which is commonly used as a base insulation layer,
spacer fabrics have significantly better wicking capabilities, a vital property when considering a
garment for activewear (Schubert, Umbach, Bartels, 2004, Spink, 2003). When taking into
account the various humidities that an athlete may encounter during regular activity, the spacer
fabrics will perform better (keeping the wearer cooler or warmer and drier) than the currently
employed three layer system which utilizes fleece as a thermal insulating layer (Spink, 2003).
In regard to thermal insulation, the fleece performed better than a spacer fabric of the same
weight (Schubert, Umbach, Bartels, 2004).
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Current Uses of Spacer Fabrics in Activewear
Spacer fabrics are currently being utilized in many applications associated with sports
and other physically exerting activities. Gloves, elbow pads, and knee pads, for any activity that
requires them, utilize spacer fabrics to act as shock absorbers should the wearer fall or incur
another type of impact. By absorbing the impact, the person is less likely to incur serious
injuries such as broken, or fractured, bones. Gloves, and other apparel and accessories for sports
have been developed to allow for full wrist movement, yet are rigid enough on one side to be
able to sustain an impact. Also, since spacer fabrics have superior breathability and thermal
insulation properties the gloves and other apparel will be comfortable to wear, regardless of the
activity (Fun with winter sports and innovative warp-knitted fabrics, 2003). Spacer fabrics can
also be incorporated into specific areas of a garment or accessory. For example, helmets can
incorporate spacer fabrics in the critical zones including the ear, neck, and crown areas thus
practically eliminating potential injuries in the case of an accident (Fun with winter sports and
innovative warp-knitted fabrics, 2003).
With conventional diving suits (SCUBA diving), which are made from neoprene, the
mobility of the diver can be inhibited, and the protection from cold water temperatures is limited
(Spacer fabrics for diving suits, 1998). When a new diving suit, constructed from a warp knitted
spacer fabric, was utilized by test divers (Appendix III), the temperature regulation, as noted by
the test subjects was superior to that of conventional neoprene; this was especially true for long
dives, to great depths. This is due to the spacer fabric having an area where air can move freely
and thus keep the wearer warmer for a longer period of time. The new suit is about one fifth less
dense, and only one fifth the weight of the neoprene suits (Spacer fabrics for diving suits, 1998).
Dow Corning Corporation® recently developed an “Active Protection System” (APS)
that is replacing the current hard surfaced protection accessories and apparel with a spacer fabric
that has been infused with a dilatant silicone. This not only makes the fabric softer and more
flexible, but also turns the spacer fabric into “body armor” (Rodie, 2006). Upon impact, the
silicone, which is normally quite flexible, becomes instantly hard and the energy from the impact
is dispersed into the surrounding spacer yarns (Figure 10) (Rodie, 2006). Multiple layers of the
APS fabric will increase the protection of the wearer, and can be strategically placed in the
garment, such as on the back and shoulders (Figure 11).
The fabric, which has been originally formulated with motorcycle riders as the ultimate
consumer, could definitely be carried into other sports, such as skiing, soccer, and football,
where high impact collisions are a real possibility. Snowboarders, for example, may fall or slide
down the side of a mountain during an accident, and could incur friction burns, and other, more
serious injuries (Anon, 1995). It is in such an instance, protective clothing that also offers
warmth and moisture wicking, such as the APS described, is necessary. Having all of the above
noted characteristics of spacer fabrics, this new form of protection will also have a longer lifespan than traditional, hard body-armor. It also has simple laundering needs, which makes it
more attractive to potential consumers. The APS fabric system exceeds European standards and
significantly better in regard to absorbing impact than tradition hard-shell protective accessories
(Dow Corning, 2007, Budden, 2006).
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Figure 10: Schematic of how the APS fabric
absorbs impact
Figure 11: Cross-section of APS fabric
Source: Dow Corning. (2007). Superior defense and comfort for high-performance apparel and
accessories NEW Dow Corning® active protection system.
Figure 12: Example of how multiple layers of APS fabric can be strategically placed in a
garment to provide ultimate protection.
Source: Dow Corning. (2007). Superior defense and comfort for high-performance apparel and
accessories NEW Dow Corning® active protection system.
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Potential Uses of Spacer Fabrics
Layering is considered to be “a key element” for one who is attempting to dress
comfortably and appropriately for sports that involve snow such as skiing or snowboarding
(Performance apparel for skiing and snowboarding, 2005). Layering is utilized so that as the
wearer can adjust to changes in the weather, or his/her level of physical exertion. “An efficient
layering system consists of three elements: a base layer for moisture management, a middle layer
for warmth and insulation, and an outer layer for weather protection” (Performance apparel for
skiing and snowboarding, 2005). With the use of spacer fabrics, these layers can be effectively
eliminated, or at least minimized providing the wearer with more range of movement due to the
decrease in bulk.
Currently, jackets utilized for winter sports can be designated as having a hard shell or a
soft shell. Hard shell jackets are designed to protect the wearer from the elements encountered
during sporting (i.e. wind, water) while also having a breathability factor. Soft shell jackets are
designed to be comfortable by wicking moisture away from the wearer’s body and provide
insulation. The soft shell jackets are generally made from fleece while a hard shell could be
made from materials such as Gore-Tex. (Performance apparel for skiing and snowboarding,
2005). Again, spacer fabrics can provide the protection from both the elements and impact,
which would eliminate the need for hard or soft shell jackets.
Ski pants and gloves are generally designed to be both waterproof and breathable on the
outside with an inside layer that provides moisture wicking and insulation. Those who
participate in winter sports may or may not utilize a base layer with their ski/ snowboarding
pants (Performance apparel for skiing and snowboarding, 2005). A spacer fabric can completely
eliminate the need for the different layers. Abrasion resistance is also a coveted attribute for
these items. Headwear for those participating in winter sports ranges from hats to actual
helmets. A lightweight helmet that is both durable and comfortable is important.
Many companies currently use down, or a down alternative, to provide the warmth
necessary when participating in winter sports (Performance apparel for skiing and snowboarding,
2005). Down feathers utilized in commercial applications have no oil on them which encourages
water absorption, therefore when the feathers become wet, they tend to stick together and their
thermal insulation properties are greatly reduced—this would be a common occurrence for those
participating in sports, as moisture from the body or from the outside environment will likely be
encountered (Bonser & Dawson, 1999).
Research from Gao, Yu, and Pan (Gao, Yu, & Pan, 2007) show down feathers to be
superior insulators to polyester, wool, and cotton (Figure 13). Though, it should be noted that
the research was conducted on virgin down, and thus the oils, which improve many of down
feather’s properties, had not been removed. Down is, by far the bulkiest material at 349.65 cm3/
g (polyester had a bulk rating of 87.11cm3/g), and while it did have notable compression and
recovery values (Figure14), the bulky physical aspect of down feathers must be taken into
account (Gao, Yu, & Pan, 2007). Down alternatives, such as Primaloft®, which can provide
insulation even when wet, do not provide insulation to the degree that spacer fabrics are able to.
Further research making direct comparisons between down feathers utilized for mass market
consumer products and spacer fabrics should be conducted. Factors such as compression,
recovery, thermal regulation, comfort, degradation, and moisture regain should be considered.
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Figure 13: Thermal conductivity of wool,
down, cotton, and polyester
Source: Gao, J., Yu, W., & Pan, N.
(2007). Structures and properties of
the goose down as a material for
thermal insulation. Textile Research
Journal, 77(8), 617.
Figure 14: Compression (top) and
recovery (bottom) characteristics of
wool, down, cotton, and polyester.
Source: Gao, J., Yu, W., & Pan, N.
(2007). Structures and properties
of the goose down as a material
for thermal insulation. Textile
Research Journal, 77(8), 617.
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Conclusion
Although spacer fabrics have many superior properties when compared to other fabrics
for outdoor or athletic wear, they are moving into this particular market rather slowly. Spacer
fabrics can, with just one layer, keep an athlete warm or cool, depending on the environment, and
dry. Maintaining the body’s microclimate is of the utmost importance for any activewear
garment, and while spacer fabrics may not always be the absolute best thermal insulators, as
when compared to fleece, their overall ability to maintain the microclimate is superior to that of
other fabrics. There is still a great deal of research that is necessary to further prove the
superiority of spacer fabrics. Comparative research regarding comfort, cost, lifespan, durability,
care, actual warmth, and deformation should be conducted. From the current research one can
see that spacer fabrics are not only better for the environment, but also consumer friendly in
regard to their easy care, decreased bulk, and potentially increased protection from
environmental elements and accidents.
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References
Anand, S. C. (2003). Proceedings from ISTEK 2003: Recent advances in knitting technology
and knitted structures for technical textiles applications.
Anand, S. Spacers—at the technical frontier. (2003). Knitting International, 110(1305), 38-41.
Anand, S. (2003). Technical overview. Knitting International, 110(1304), 49.
Anon. (1995). Softer landings.
Bonser, R.H.C, Dawson, C. (1999). The structural mechanical properties of down feathers and
biomimicking natural insulation materials. Journal of Materials Science Letters, 18, 17691770.
Breathing room. (2002). Retrieved from
http://www.inteletex.com/FeatureDetail.asp?PubID=27&NewsId=191.
Budden, G. (2006). Defense and comfort: new advancement in impact-protection textiles.
Technical Textile Technology.
Building performance into outdoor wear. (2002). Canadian Apparel, 26(2), 10.
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Appendix
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Appendix I: Comparison of Properties of Warp and Weft Knitted Spacer Material
Comparison of Properties of Warp and Weft Knitted Spacer Material
Yarn used: 100% polyester in both cases
Dimensional Properties
Warp Knitted
Weft Knitted
Spacer Fabric
Spacer Fabric
Area Density (g/ m-2)
417.2
431.8
Thickness (mm)
2.9
2
-3
Bulk Density (g/ cm )
0.143
0.215
Tensile Properties
Tenacity (Ntex-1)
Course Direction
Wale Direction
45° Direction
Breaking Extension (%)
Course Direction
Wale Direction
45° Direction
Modulus (Ntex-1)
Course Direction
Wale Direction
45° Direction
0.038
0.037
0.033
0.031
0.031
0.032
185.53
137.96
167.66
142.1
153.3
132.2
1.85
1.37
1.67
1.41
1.53
1.31
Comfort Properties
Alambeta
Thermal Resistance (W-1Km2)*10-3
Dry
63.42
38
Wet 0.5ml
24.9
15.1
Wet 1ml
23.8
10..2
Thermal Absorptivity (Wm-2S1/ 2K-1)
Dry
82.08
98.56
Wet 0.5ml
246.6
460.3
Wet 1ml
269.66
633.3
Permatest
6.51
14.95
Water Vapor Permeability (%)
2
-1
0.124
0.0498
Resistance to Evaporate Heat Loss (m PaW )
3.53
2.89
Absorption
Wicking
Course Direction
18.68
0.52
Wale Direction
28.3
0.36
Area
23.00
0.43
Source: Anand, S. C. (2003). Proceedings from ISTEK 2003: Recent advances in knitting
technology and knitted structures for technical textiles applications.
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Appendix II: Properties of Sportwool™ Manchester United Football (Soccer) Strip
Properties of Sportwool™ Manchester United Football (Soccer) Strip
Area Density (g/ m-2)
161.23
Thickness (mm)
0.64
-3
Bulk Density (g/ cm )
0.252
Alambeta
Thermal Resistance (W-1Km2)*10-3
Dry
24
Wet 0.5ml
10
-2
-1
Thermal Absorptivity (Wm S1/ 2K )
Dry
83
Wet 0.5ml
328
Permatest
36.5
Water Vapor Permeability (%)
2
-1
0.0155
Resistance to Evaporate Heat Loss (m PaW )
3.59
Absorption
Wicking
Course Direction
3.64
Wale Direction
2.61
Area
3.08
Source: Anand, S. C. (2003). Proceedings from ISTEK 2003: Recent advances in knitting
technology and knitted structures for technical textiles applications.
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Appendix III: Details of Warp Knitted Spacer Submerser Diving Suit
Fabric Type
Fabric Thickness
Weight
Material
Production Machine
Gauge
Fabric Manufacturer
Suit Producer
Warp knitted spacer fabric, elastic
3.5 mm
330 g/ m2
45% polyester, 36% elastane, 19% CoolMax®
RD 6 N raschel machine, double bar
E 18
Müller Textil
Beluga Tauchsport
Source: Spacer fabrics for diving suits. (1998). Kettenwirk Praxis, 32(4), 57.
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