Seth Moczydlowski
Effect of Screen Printing Ink on the Thermal Performance of Running Shirts
Total Evaporative Resistance, Ret
Measuring Total Thermal Resistance, Rt:
Running shirts are offered in a variety of styles and colors and
marketed with trademarked names to promote the performance
qualities of the fabric. These garments also frequently are screen
printed with logos and graphics promoting companies or sponsored
running events. Commercial screen printing operations generally use
a heat-cured plastisol ink consisting of PVC resin and a plasticizing
agent. When cured at around 160°C, the resin particles absorb the
plasticizer and merge to create a thin, uniform, plastic film [3]. The
film is durable and abrasion resistant to remain visible and intact
throughout the life of the garment including repeated washing and
drying. Unfortunately, this film also acts as a watertight barrier,
reducing the amount of surface area available for evaporation and
potentially limiting the wicking performance of the garment.
2.0 OBJECTIVE
1) Determine the impact of screen printed graphics on the thermal performance of lightweight,
wicking polyester running shirts using a thermal manikin.
2) Provide a set of recommendations that can be used either by apparel companies concerned
with the design of high-performance running shirts or by athletes when selecting garments
for purchase.
3.0 MATERIALS AND METHODS
A survey of store-bought running shirts with screen-printed graphics revealed a range of ink
coverage from 2% to 16% of the measured flat-pattern area, with an average of 9% coverage.
Samples:
Three white running shirts made of 100% 4.0 ounce weight polyester wicking fabric.
• All shirts were modified with zipper on the left shoulder to enable quick garment change on
thermal manikin.
• Two shirts were hand-screened with different patterns using glossy black plastisol ink. Ink
was cured to 160°C using a heat gun and laser-sighted infrared thermometer.
• Overall, the ensemble exhibited a negligible increase in evaporative resistance
• Focusing solely on the Torso [Zones 13,14,15,16,17,18], however, shows a significant
increase in evaporative resistance. There was a 7% increase with the grid pattern, and a full
25% increase in evaporative resistance of the torso area from the block pattern.
• Thermal resistance is the measure of a garment’s
resistance to a heat flow over a temperature gradient.
Clothing articles with a higher thermal resistance require
less energy to maintain a given temperature gradient.
• Total thermal resistance is the thermal resistance of the
garment, and the air layer enclosed above the skin.
• Testing was conducted according to ASTM F1291-04
“Standard Test Method for Measuring the Thermal Insulation
of Clothing Using a Heated Manikin” [4].
• Chamber conditions were held constant at 23°C and 50%
relative humidity. Manikin skin temperature was held
constant at 35°C.
• Manikin was dressed in clothing ensemble to be tested and
data measurements were taken using control software every
minute until steady state conditions were achieved.
• Steady state was defined as a constant reading of manikin
skin temperature and power input within ±3% over a period
of 30 minutes.
• The test was replicated a total of 3 times for each shirt and
the results were obtained using an area weighted average
to calculate the Total Thermal Resistance.
0% Area
Evaporative Resistance
[kPa·m²/W]
Today’s running enthusiast has a variety of options when selecting athletic garments to purchase.
It is common knowledge that lightweight, wicking polyester fabric will keep the wearer drier and
more comfortable than a similarly cut cotton garment [1]. Besides a reduction in comfort, excessive
moisture can increase the effects and occurrence of chafing and irritation during exercise [2], and
make clothing stick to skin, potentially limiting mobility.
0% Area
• Overall, no significant change in thermal resistance was noted.
18% Coverage
Thermal Resistance
[°C·m²/W]
Full – Block Pattern
18% Coverage
Coverage Area: 0.068 m²
0.15
0.1
0.05
0
Full Ensemble
Torso
• Locally, a thermal resistance increase of 10% was indicated over the Zone 15, the Stomach.
0% Area
0.3
0.25
0.2
0.15
0.1
0.05
0
Upper Chest
Shoulders
Stomach
Mid Back
120
100
80
60
40
20
0
Upper Chest
Shoulders
Stomach
Mid Back
Waist
Lower Back
The results clearly show an increase in evaporative resistance of the stomach and upper chest
due to the presence of the PVC graphic pattern blocking airflow and reducing surface area
available for evaporation. Users wearing this garment would experience a noticeable increase
in moisture in the chest and stomach region during athletic activity compared with the rest of
the garment. The increase in moisture could lead to chaffing and irritation during vigorous
exercise.
5.0 CONCLUSIONS & FUTURE WORK
Future Work:
Next steps for this work will include design of an athletic shirt product line using the above
guidelines.
6.0 REFERENCES
18% Coverage
0.35
Thermal Resistance
[°C·m²/W]
Methods:
Testing was conducted using a 34-zone
Newton model thermal manikin in the form
of a 50% human. The manikin accurately
simulates metabolic heat output of the
human body using a computer controlled
system of heating elements and sensors.
The system also has the ability to “sweat”
via micro-pump-controlled pores positioned
throughout the body and a removable skin
suit that evenly distributes moisture over the
surface . The manikin is housed in a temperature controlled
chamber that maintains environmental conditions at a specific
temperature from 10 to 40°C and 30 to 70% relative humidity (RH).
9% Coverage
18% Coverage
Recommendations for Design/Use of Screen Printed Graphics on Polyester Athletic Shirts:
• For minimal negative effect, keep the coverage area of screen printed designs at or below 5%
of the flat-pattern shirt area.
• Avoid graphic designs with large solid block ink sections. Use of patterns can help provide a
large perceived graphic size, while using minimal amounts ink.
• Maintain a consistent ink coverage area throughout product lines or athletic wear wardrobe.
Wearing new and/or different clothing articles on “race-day” can negatively affect performance.
0.2
Half - Grid Pattern
9% Coverage
Coverage Area: 0.034 m²
9% Coverage
Conclusions:
The experiment confirmed that plastisol screen printing ink does have a measurable negative
effect on the thermal performance of wicking polyester athletic shirts. While a slight local increase
of 10% thermal resistance was recorded, local increases in evaporative resistance were
measured as high as 139%.
Thermal Resistance, Rt
Blank – No Pattern
0% Coverage
Total Shirt Area: 0.371 m²
Torso
• The stomach zone exhibited the highest increase of139% with the block pattern.
• The upper chest also showed increases of 10% and 27% for the grid and block patterns ,
respectively.
• Interestingly, the mid-back reduced its evaporative resistance by around 10%.
4.0 RESULTS AND DISCUSSION
9% Coverage
18% Coverage
Full Ensemble
Measuring Total Evaporative Resistance, Ret:
• Evaporative resistance is the measure of a garment’s ability to resist the evaporation of water
through the piece of clothing. Clothing with a higher evaporative resistance will evaporate
less water through the garment given a constant environment.
• Total evaporative resistance is the evaporative resistance of the garment, and the air layer
enclosed above the skin.
• Testing was conducted according to ASTM F2370-05 “Standard Test Method for Measuring
the Evaporative Resistance of Clothing Using a Heated Manikin”[5].
• Chamber conditions were held constant at 35°C and 40% relative humidity. Manikin skin
temperature was held constant at 35°C.
• Manikin skin was applied and wetted to ensure full saturation. Sweat pumps were turned on
and set to pre-determined flow-rates.
• Manikin was dressed in clothing ensemble to be tested and data measurements were taken
using control software every minute until steady state conditions were achieved.
• Steady state was defined as a constant reading of manikin skin temperature and power input
within ±3% over a period of 30 minutes.
• The test was replicated a total of 3 times for each shirt and the results were obtained using
an area weighted average to calculate the Total Evaporative Resistance.
0% Area
9% Coverage
40
35
30
25
20
15
10
5
0
Evaporative Resistance
[kPa·m²/W]
1.0 INTRODUCTION
Waist
Lower Back
The slight increase in thermal resistance of the Stomach zone indicates that the PVC graphic
does provide some insulative value to the fabric. However, when averaged over the entire
garment and ensemble, these increases are washed out and show no change in thermal
resistance.
[1] "Chafing." Skin Chafing Causes, Treatments, Prevention. Ed. Varnada Karriem-Norwood.
WebMD, 31 Aug. 2012. Web.
[2] Greene, Warren. "Proper Attire." Proper Running Attire at Runner's World. Runner's World, 10
Feb. 2004. Web.
[3] "Water Based Ink vs Plastisol." OoShirts, 28 Nov. 2012. Web.
[4] ASTM Standard F1291-04, "Standard Test Method for Measuring the Thermal Insulation of
Clothing Using a Heated Manikin" ASTM International, West Conshohocken, PA, 2004.
[5] ASTM Standard F2370-05, "Standard Test Method for Measuring the Evaporative Resistance
of Clothing Using a Sweating Manikin" ASTM International, West Conshohocken, PA, 2005.
ACKNOWLEDGMENTS
Philadelphia University Research Center – Laboratory for Engineered Human Protection
Professor Janet Brady and Wendy Anderson for advising and screen printing tips.
Jennifer James for seamstress skills and moral support.