uniformity comparison of selected spunbond fabrics - ortega · 2017. 4. 7. · nylon spunbond’s...
TRANSCRIPT
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Building a better future serving the world
Uniformity Comparison of Selected Spunbond Fabrics
AFS 2017 Spring ConferenceApril 12, 2017
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Purpose of Study
Optically
Using previously presented Avintiv Uniformity Indices
Using transmitted light data
• Compare uniformity of flat spunbond nylon fabric to flat spunbond polyester fabric
• Discuss advantages of more uniform fabric
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Optical Comparison (20 gsm spunbond fabrics)
Polyester Nylon
Sample size is 17 cm by 15 cm
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Subjectively, most people agree that the optical uniformity of nylon is better than polyester
Sample size is 17 cm by 15 cm
Optical Comparison (34 gsm spunbond fabrics)
PolyesterNylon
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Avintiv Uniformity Indices
M2 = (sbasis weight + sthickness ) * 100
More uniform fabrics have a “Lower” index
These indices were developed by Avintiv to compare materialsReference: “Impact of Substrates on Nanofiber Formation” Betty J. Wells; AFS 2015 Fall Conference October 7, 2015
M3 = (sbasis weight + sthickness + sair permeability ) * 100
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Sampling Plan and Test Methods
• Commercially available polyester spunbond fabrics were purchased at a minimum width of 64 inches
• Basis weights between 20 and 51 gsm
• 10 samples taken in the machine direction
• Cross directional samples taken every 30 cm
Basis Weight Thickness Air Perm
D3776 D1777 D737
ASTM Test Methods
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1.30
1.63
1.32
1.62
1.82
1.39
2.31
2.71
2.87
1.80
2.51
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
20 25 29 34 36 46 46 51
Bas
is W
eigh
t St
and
ard
Dev
iati
on
(gs
m)
Basis Weight (gsm)
Standard Deviation of Basis Weight Measurements for Nylon and Polyester Spunbond Fabrics
Basis Wt Std dev (gsm) 4 dpf Nylon
Basis Wt Std dev (gsm) 4 dpf PET
Basis Wt Std dev (gsm) 2 dpf Polyester
Basis Weight Variability
Mass distribution of 4 dpf nylon spunbond fabrics is less variable than 2 or 4 dpf polyester fabrics
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Thickness Variability
0.42
0.330.39 0.36
0.45
0.64
0.91
1.181.15
0.54
0.66
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
20 25 29 34 36 46 46 51Basis Weight (gsm)
Thickness Std dev (mils) 4 dpf Nylon
Thickness Std dev (mils) 4 dpf Polyester
Thickness Std dev (mils) 2 dpf Polyester
Thic
knes
s St
and
ard
Dev
iati
on
(m
ils)
Standard Deviation of Thickness Measurements for Nylon and Polyester Spunbond Fabrics
Thickness variability of nylon fabrics is considerably less than polyester fabrics
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172
195171
198
227
204
322
388401
234
317
50
100
150
200
250
300
350
400
450
20 25 29 34 36 46 46 51
M2
In
dex
Basis Weight (gsm)
4 dpf Nylon
4 dpf Polyester
2 dpf Polyester
M2 Uniformity Index
M2 uniformity index of nylon spunbond is much lower than polyester spunbond indicating the nylon has a more uniform filament distribution
(sbasis weight + sthickness ) * 100
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187
8881
42 40
255
194
159
122
99
62
0
50
100
150
200
250
300
20 25 29 34 36 46 46 51
Basis weight (gsm)
Air Perm Std dev 4 dpf Nylon
Air Perm Std dev 4 dpf Polyester
Air Perm Std dev 2 dpf Polyester
Air Permeability Variability
Standard Deviation of Air Permeability Measurements for Nylon and Polyester Spunbonds
Air
Per
mea
bili
ty S
tan
dar
d D
evia
tio
n (
ft3/m
in/f
t2)
Air permeability variability of nylon fabrics is less variable than polyester fabrics
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18909
89588279
4444 4238
25667
19768
16285
12612
10140
6543
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
20000
22000
24000
26000
20 25 29 34 36 46 46 51
M3
In
dex
Basis Weight (gsm)
4 dpf Nylon
4 dpf Polyester
2 dpf Polyester
M3 Uniformity Index
Nylon spunbond’s M3 index is less than half that of polyester spunbond fabric confirming nylon has a much more uniform filament structure
(sbasis weight + sthickness + sair permeability ) * 100
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On-Line Camera Inspection system
On-line camera system provides grey scale output of transmitted light showing thick and thin spots on fabrics
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2
15
43
133
193
125
36
48
35
71
107
130
91
45
35
19
61
0
50
100
150
200
145 150 155 160 165 170 175 180 185 190 195 200 205 210
Fre
qu
en
cy
Transmitted light Intensity
Variance (σ2) of transmitted light intensity for 20 gsm nylon spunbond is 63% lower than for polyester spunbond.
Histogram of transmitted light intensity for 20 gsm spunbond fabrics
Optical Representation of Fabrics
NylonStd Dev: 5.8Variance: 33
PolyesterStd Dev: 9.5Variance: 90
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3
16
55
101
9397
91
38
107
19
4549
65
8184
70
62
27
117
2 3
0
20
40
60
80
100
120
115 120 125 130 135 140 145 150 155 160 165 170 175 180 185 190
Fre
qu
en
cy
Intensity
Histogram of transmitted light intensity for 34 gsm spunbond fabrics
Optical Representation of Fabrics
Variance of transmitted light intensity for 34 gsm nylon spunbond is less than half that of polyester
NylonStd Dev: 8.4Variance: 71
PolyesterStd Dev: 12.1Variance: 147
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Summary Nylon Compared to Polyester
Nylon Polyester
• Visually more consistent
• Avintiv M2 and M3 indices are better
• Lower variability of physical properties
• Lower variability of transmitted light
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Case Study – Nanofiber ApplicationSimilar Process Conditions
Efficiency 34 gsm Cerex® 46 gsm Polyester
Average 91.6 93.7
Std Dev 1.2 2.4
Variance
When nanofibers are applied to a lighter weight nylon substrate, the variance of efficiency measurements is 75% lower than that of the same media substituting a
heavier weight PET substrate
1.4 5.7
TSI 8130 @32 lpm (0.3 μ particle)
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0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
87 88 89 90 91 92 93 94 95 96
Efficiency (%)
MIN
IMU
M E
FFIC
IEN
CY
SPEC
Nylon SubstrateSTD DEV=1.2
Polyester SubstrateSTD DEV=2.4
FAIL
UR
E
Benefits of using nylon substrate to form nanofibers
Nylon’s higher uniformity allows the use of a lighter substrate to achieve the same minimum design performance
Nanofiber media made with 34 gsm nylon and 46 gsm polyester with different efficiencies
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Potential benefits for filtration applications
• Increases consistency in filter media performance in nanofiber, meltblown and membrane casting production
• Minimizes downstream fiber migration, contaminate shedding and channeling in dynamic flow applications
• Combined with nylon’s greater strength, temperature and chemical resistance enables high performance advanced media designs
Improved uniformity in nylon….
• Provides more consistent protection against burst failures during system pulsations and better media protection during pleating
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Please visit our booth display or contact us for additional information about CEREX Advanced Fabrics’
high quality spunbond Nylon products.
Albert E. OrtegaDirector of TechnologyCerex Advanced Fabrics, Inc.
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Related Work Previously Presented at AFS Conferences
• “The Advantages of Nylon Nonwovens in Filtration”; Ortega, Carter; AFS 2013 Spring Conference; May 8, 2013
• “Longer Life Nylon Spunbond Fabric For Filtration Media”; Forcucci; AFS 2016 Fall Conference; October 25, 2016
• Using Nylon 6,6 Spunbond Fabric to “Prevent Catastrophic Filter Media Failure Caused by Ethylene Glycol Contamination”; Ortega, Carter; AFS 2015 Fall Conference: October 7, 2015