New Cell Structure Control Technology for Ultra-High Air Flow Viscoelastic Polyurethane Foam
Kaoru Aou, Harper Meng, Chris Thiede,
Dale Hunter, Van Delk Jr., Michelle Thomas
2016 Polyurethanes Technical Conference
September 2016
Page 1
Current State: PU Foam = Durability, Not Air Flow. Other Materials = Poor Durability
• If we can make a Higher Air Flow PU Memory Foam, this would combine advantage of breathability with durability and pressure relief. Proposed: this would provide Superior Sleep Comfort
Page 2
Hammocks
Coconot Coir
Straw
Array of
Metal
Springs
K.Aou, Sep. 2016
Images from
Wikimedia
Commons
What is Ultra-High Air Flow Foams, and Should it Matter?
• New Technology = much higher air flow than before
• What is considered comfort?
• Humidity and Temperature being in a certain range (Human Comfort Model from U-Berkeley)
• We believe higher air flow memory foam would improve comfort
• “High Air Flow Foam doesn’t matter, there’s no air flow once memory foam is compressed”
• Less tortuous = under compression, air flow should be better retained than incumbent materials
Page 3K.Aou, Sep. 2016
Lower Air Flow Visco Foam (<1 ft3/min)
Control High Air Flow Visco (3-4 ft3/min)
New Technology (Ultra-High Air Flow)
Visco (7-9 ft3/min)
Mechanical Properties of Large Foam Buns
• We can get good enhancement of air flow as well as tear strength, while mostly maintaining IFD and 90% compression set.
Page 4K.Aou, Sep. 2016
Properties
New Technology
Visco Control Visco
IFD @ 25% Deflection (lbf) 9.1 8.3
IFD @ 65% Deflection (lbf) 20.6 16.9
IFD @ 25% Return (lbf) 8.0 7.8
IFD Support Factor 2.26 2.03
IFD Hysteresis(%) 87 94
Air Flow (scfm) 7.9 3.0
Average Resiliency(%) 4 1.2
Tear Strength (lbf/in) 1.30 0.77
Ten. Strength (psi) 11.9 5.3
% Elongation 96 109
Density (lb/ft3) 2.77 2.97
90% CS (CT) 1.4 1.7
But there’s that question…..
“High Air Flow Foam doesn’t matter, there’s no air flow once memory foam is
compressed?”
Is it true? To confirm or reject the statement, we need data.
Page 5K.Aou, Sep. 2016
Measurement of Air Flow Under Compression
ASTM Air Flow Tester
Foam in Tester
(For ASTM D3574 Test, stop here)
Bottom Copper Mesh
Stacking 2 foam pieces (for 50%
compression) on Tester
Top Copper Mesh
Compressed Flat,
Ready for Modified Test
K.Aou, Sep. 2016 Page 6
Foam Air Flow Under Compression
Page 7
1. With New Technology, air flow is maintained at reasonable levels under compression.
2. %Difference between Control & New Technology widens under compression
K.Aou, Sep. 2016
0
1
2
3
4
5
6
7
8
9
10
0% 20% 40% 60% 80% 100%
Mo
dif
ied
AST
M A
ir F
low
(ft
3/m
in)
Compressive Strain
New TechnologyControl ViscoLower Air Flow Visco (TDI)
67% compression
(3 foams stacked)
50% compression
(2 foams stacked)
How do we target Sleep Comfort?
• What is needed for comfort?
• Usually, when sleeping, traditional memory “sleeps warm” – target is to lower that.
• Temperature & %RH in certain range
Page 8
Time Since Lying on Bed
Mattress
Temperature
Or %RH
Near Body
Target Profile
Zone of
Comfort
“Warm / Hot Sleep”
Too Cool
Low Air Flow
Visco Foams
We believe higher air
flow materials can help
K.Aou, Sep. 2016
Current Best New Technology foam
What would High Air Flow Foams Do for Human Comfort?
• Human Comfort Model (following ASHRAE standard) has been used in apparel and HVAC areas.
• Higher Air Flow = more breathable, and allows human body to self-regulate (in this case, cool more when hot)
Page 9
http://comfort.cbe.berkeley.edu/
K.Aou, Sep. 2016
Temp.
Moisture Level
32 °C, 90%RH
Parameter inputs affect where is Zone-of-Comfort:
• Room temperature
• Clothing level
• Metabolic rate
• “Wind” speed
Etc…
New Technology
Visco foamCurrent Best
Visco foam
Reticulated
Foam
Faster wicking and greater extent of wicking is seen with New Technology Visco foam.
New Technology Imparts Superior Wicking
Side-on view of phenomenon
Vertical wicking for 1 min.:
New Technology(Left, 6 mm)
Control Visco (Right, 2 mm)
Page 10K.Aou, 18th May 2016
Summary
• New Technology (Ultra-High Air Flow) Visco Foam showed the following improvements while maintaining IFD and density:
• Enhanced Air Flow
• Improved Tear Strength
• Under compression, maintains air flow much better than Control (Visco)
• Superior Wicking Capability relative to Control (Visco) as well as High Resiciliency (HR) and conventional Flex foams
• It is believed that these qualities are beneficial for future mattress designs
Page 11K.Aou, Sep. 2016
