Technical Information (Revised 2023.4)

ZYLON®(PBO fiber) Technical Information (2023)
Contents
1. Basic properties
2. Comparison of mechanical properties with other fibers
3. Influence of twist on tensile properties
4. Creep properties
5. Thermal properties
5.1 Decomposition Temperature
5.2 Isothermal weight loss
5.3 Strength retention after thermal treatment
5.4 Strength retention at high temperature with humidity
5.5 Effect of temperature on strength and modulus
5.6 Hot air shrinkage
5.7 Flame resistance
5.8 Combustion products
6. Light resistance
7. Chemical resistance
7.1 Organic mediums
7.2 Inorganic mediums
7.3 Seawater resistance
8. Moisture pick-up
9. Miscellaneous
9.1 Compressive strength
9.2 Knot and loop strength
9.3 Thermal expansion coefficient
9.4 Heat capacity
9.5 Abrasion resistance between fiber and metal

2

1. Basic PropertiesZYLON®(PBO fiber) is the next generation super fiber with strength and modulus almost
doubles that of p-Aramid fiber. ZYLON® shows 100C higher decomposition temperaturethan p-Aramid fiber. The limiting oxygen index is 68, which is the highest among organic
super fibers.
There are two types of fibers, AS (as spun) and HM (high modulus). HM is different fromAS in modulus, moisture regain and etc.
ZYLON® ASZYLON®HM

Filament decitex

1.7

1.7

3(g/cm )

1.54

1.56

(cN/dtex)

37

37(GPa)5.8

5.82(kg/mm )

590

590

(cN/dtex)

1150

1720

(GPa)

180

270

18000

28000

Elongation at break(%)

3.5

2.5

Moisture regain(%)

2.0

0.6

Decomposition Temp.(C)

650

650

LOI

68

68

Thermal expansion coefficient--6x10-6

DensityTensile Strength

Tensile Modulus

2(kg/mm )2. Comparison of mechanical properties with other fibers
ZYLON® has the highest tensile strength and tensile modulus among high-performancefibers.
Tenacity

ModulusElongation

Density%g/cm

3%

cN/dtex GPa cN/dtex GPa

MoistureRegain

LOI

Heat
Resistance*
CZylon® AS

37

5.8

1150

180

3.5

1.54

2.068650

Zylon® HM

37

5.8

1720

270

2.5

1.56

0.6

68

650

p-Aramid(HM)

19

2.8

850

109

2.4

1.45

4.5

29550

m-Aramid

4.5

0.65

140

1722

1.38

4.5

29400

Steel Fiber

3.5

2.8

290

200

1.47.80HS-PE35

3.5

1300

110

3.5

0.97

0

16.5

150

PBI

2.7

0.4

45

5.6

30

1.4

1541

550

Polyester

81.1

125

1525

1.38

0.4

17260

*Melting or Decomposition Temperature

3The stress-strain curves of ZYLON® compared with other high-performance fibers areshown below.

3. Influence of twist on tensile propertiesZYLON® is shipped with zero twist. A certain twist has to be applied in order to measureits correct tensile strength. These figures show the influence of twist factor on tensile
strength and modulus for 555 dtex ZYLON® yarn. For different dtex yarns, optimum
twist level can be estimated by using twist factor. Twist factor is defined by the followingformula.

1400

45

2000401200401800351000

3516003080030

1400
Zylon HM 555dtex

Zylon AS 555dtex
25600
0510152025

1200
0

Twist Factor

510Twist Factor

41520

Modulus(cN/dtex)

45

Modulus(cN/dtex)
Tenacity(cN/dtex)

Strength(cN/dtex)

Twist factor (TF) = 0.124 x (turns per inch) x (dtex)0.5

4. Creep PropertiesZYLON® has superior creep resistance to p-Aramid fibers. (Creep means anon-recoverable strain after prolonged static loading.) When a certain load is applied toyarn, recoverable strain (initial strain) and non-recoverable strain are observed. ForZYLON® HM, non-recoverable strain after 100 hours under 50% of breaking load (Safetyfactor (SF)=2) is less than 0.03%.
2.00

100

Stress(% of breaking load)

1.75

Strain(%)

1.50
1.25
1.00
Zylon AS
Zylon HM
p-Aramidp-Aramid HM

0.75
SF=20.50
0.109080

7060501101001000

Zylon HM

111010Time(hr)21010019 years
3101000

10000
104 100000
105 100000
106 100000
107000Time to Failure(min)Creep Parameter
Creep parameters (slope of straight line in above figure) are compared with p-Aramidfibers. ZYLON® shows less than half of creep parameter of p-Aramid fiber. Creep strain
is measured under 50% of the breaking load for each fiber. Note that the actual load
applied to ZYLON® is almost double that of p-Aramid fiber.
Creep parameter under 50% of breaking strength
Zylon ASZylon HMp-Aramidp-Aramid HM

3.2×10-4

1.1×10-4

5.0×10-42.5×10-4

Time to failure
After a certain loading time, yarn breakage may occur. The above figure shows therelationship between time to failure and applied load level (ZYLON®HM). Based on theextrapolation, 107 minutes (19 years) of time to failure can be estimated under 60% of thebreaking strength.

5100

100

8080
Residual Weight(%)

Residual Weight(%)

5. Thermal properties
5.1 Decomposition Temperature
ZYLON® has a 100C higher decomposition temperature than p-Aramid fibers. Thermal
gravimetric analysis charts in air and argon gas are shown below. The heating rate is20C/min.

60in air40Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

2060in Ar40Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

20000

100

200

300

400

500

6000700

100200300

400

500

600

700

Temperature(℃)

Temperature(℃)

5.2 Isothermal weight loss
A significant difference of weight loss behavior is observed at 500C between ZYLON®
and Aramid fibers.
10010080

Residual Weight(%)

Residual Weight(%)

500℃6040
Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

20806040Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

20400℃

00050100Time(min)1502006050100Time(min)1502005.3 Strength retention after thermal treatment
These figures show the effect of thermal treatment in air on residual strength.
ZYLON®HM shows a little higher heat resistance than ZYLON®AS.
100100Zylon HM200℃

8060

Strength Retention(%)

Strength Retention(%)

Zylon AS250℃

40300℃

20200℃

80250℃
6040300℃
20350℃

400℃

400℃

0350℃

0110100

1000

110Time(hr)1001000Time(hr)Strength retention after thermal treatment is compared with Aramid fibers at severaltemperatures.
100100250℃
Strength Retention(%)

Strength Retention(%)

806040Zylon AS
Zylon HM
p-Aramidp-Aramid HM
copoly-Aramid

20806040
ZYLON ASZYLON HM

20p-Aramidp-Aramid HM

200℃

copoly-Aramid

000250500

750

1000Time(hr)0200400Time(hr)

7600

100

Strength Retention(%)

80

6040100Zylon AS
Zylon HM

Strength Retention(%)

Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

80p-Aramidp-Aramid HM
copoly-Aramid

60402020350℃

300℃
000501000150

1010080
Strength Retention(%)

Strength Retention(%)

100Zylon ASZylon HM
p-Aramid HM
copoly-Aramid

400℃
60406040500℃

202000051030Time(hr)Time (hr)80201520Zylon ASZylon HM
p-Aramidp-Aramid HM

03060Time(sec)Time (hr)8901205.4 Strength retention at high temperature with humidity
The strength of ZYLON® decreases in the condition of high temperature and highhumidity. The residual strength after a 50 hours treatment with saturated steam at 180Cis 40-50%, which is between p-Aramid and copoly-Aramid fiber.

100

1006040Zylon ASZylon HMp-Aramid
copoly-Aramid

2080

Strength Retention(%)

Strength Retention(%)

80

10250℃

604020180℃00Zylon ASZylon HM
p-Aramid
copoly-Aramid

2030400500Time(hr)1020304050Time(hr)The strength of ZYLON® gradually decreases even at the temperature of less than 100Cin high humidity condition. ZYLON® fiber should be stored free from high humidity atnormal room temperatures.

8080Strength Retention (%)

100

Strength Retention(%)

100

604080℃

206040Room temperature andhumidity at warehouse

2060℃

40ºC 80%RH

80% RH40℃Zylon AS 555dtex

000204060Time(day)80

1000200

400

600

Time (day)

9800

1000

5.5 Effect of temperature on strength and modulus
The relative strength of ZYLON® decreases from room temperature to 500C. ZYLON®
retains 40% of the room temperature strength even at 500C.
The temperature dependence of modulus is shown below. Even at 400C, ZYLON®
retained 75% of modulus at room temperature.

8080
Relative Modulus(%)

100

Relative Strength(%)

1006040
Zylon AS
Zylon HM
p-Aramidp-Aramid HM

206040Zylon AS
Zylon HM
p-Aramid HM

20000

100200300

4005000Temperature(℃)

100200300
Temperature(℃)

5.6 Hot air shrinkage
Shrinkage (permanent) after hot air treatment for 30 minutes without load was measured.
ZYLON® shows very low shrinkage as compared with other super fibers.
2.5
Zylon AS
Zylon HM
p-Aramid
copoly-Aramid

Shrinkage(%)

21.5

10.500100200Temperature(℃)

10300400400

5.7 Flame resistanceZYLON® shows extremely high flame resistance. In a vertical flame test (JIS L1091 A-4),
char length is almost zero.
Zylon
warp

fill

p-Aramidm-Aramid

warp

fill

warp

fill

32

6

6Char length(cm) <0.5 <0.5
After flame(sec)

0

0

0

000

After glow(sec)

11

16

16

2

268

LOI

29

29

Plain woven fabrics with 20's spun yarn

5.8 Combustion products
Generated gases at the temperature of 750C were measured according to JapaneseIndustrial Standard (JIS). The amount of toxic gases such as HCN, NOx and SOx fromZYLON® is very small compared with p-Aramid fiber.
101122660

Zylon
p-Aramid

25.1
2010

Product Amount(mg/g)

8750℃
6420CO

CO2 NH3 HCN HCl NOx SOx

Decomposition gases at 500C were also measured. In the process of glass molding or
aluminum extrusion, cushion materials such as felt are heated sometimes up to about
500C. The amount of toxic gases from ZYLON® was also small at that temperature.

Zylon

p-AramidTemp.

COCO2NH3HCNHClNOxSOx

500

6.9

35.8

0.35

1.48

<0.010.15<0.017501>

2660

0.05>

0.57

<0.01

0.16

0.15001071230

3.95

14.8

<0.01

1.00

1.40

750112

20100.05>

25.1<0.010.47

1.04mg/g

11

6. Light resistance
The strength of ZYLON® decreases with exposure to sunlight. Light resistance ofZYLON® was evaluated using Xenon light weather-ometer. As shown below, the strength
decreases sharply at the initial stage of exposure. End products of ZYLON for outdoor
use have to be protected by covering materials. The residual strength of ZYLON® after 6months exposure to daylight is about 35%.
12010083℃

Strength Retention (%)

80
Strength Retention(%)

Zylon AS

1006040Zylon ASZylon HMp-Aramidp-Aramid HM

200Zylon HM
80604045°south
Ohtsu, Japan
97/6 - 97/11

20Xenon wether-ometer

00100

200

300

400

500

0

1Time (hr)2345Time (month)ZYLON® should be protected not only from ultraviolet light but also from visible light.
These data show strength retention after exposure to fluorescent lamp.
100

Strength Retention(%)

80604020ZYLON ASZYLON HMFluorescent lamp (35W x 2)
150 cm from lamp
00200400Time(hr)

12600

8006

7. Chemical resistance
7.1 Organic mediums
ZYLON® is stable with most of organic mediums.
Strength retention(%) after immersion
for 500 hrs at room temperature
Chemicals

Zylon ASZylon HM

Methylethylketone

10099

Dimethylformamide

10097

Methanol

10099

Gasoline

10095

Brake Fluid

10096

100

8080
Strength Retention(%)

1006040Zylon AS
Zylon HM
p-Aramidp-Aramid HM
copoly-Aramid

206040Zylon AS
Zylon HM
p-Aramidp-Aramid HM
copoly-Aramid20H2SO4 60%
25℃0HCl 20%
25℃

00100200300Time(hr)100400500

0100200300Time(hr)80Strength Retention(%)

Strength Retention(%)

7.2 Inorganic mediums
Exposure to strong acids causes strength losses. However, ZYLON® is more stable thanp-Aramid.

604020Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

HNO3 20%
25℃

100

400

00200300Time(hr)13500

4005001001008080
Strength Retention(%)

Strength Retention(%)

ZYLON® is stable to alkaline at room temperature. NaClO (bleach) does not cause
strength loss for ZYLON® at room temperature.

6040Zylon ASZylon HM
p-Aramidp-ramid HM
copoly-Aramid

2060

100200300Time(hr)400Zylon ASZylon HM
p-Aramidp-Aramid HM
copoly-Aramid

20NaOH 20%25℃

00NaClO 5%25℃

4005000100200Time(hr)300400At higher temperatures, the strength of ZYLON® AS staple fiber decreases in acid andalso in alkaline.

10080

Strength Retention(%)

Strength Retention(%)

100604020Staple Fiber
5% H2SO4, 75℃Zylon
m-Aramid
PBI

p-Aramid
PPS80Zylon

p-Aramidm-AramidPPSPBI

604020Staple Fiber
10%NaOH 75℃00050100150Time(hr)

200

250

14050100150Time(hr)2002507.3 Seawater resistance
Seawater simulation shows a similar strength loss to high humidity condition.

Strength Retention (%)

10080604020Zylon ASp-Aramid

30°C
3.5%NaCl00100

200
300
Time (day)

400

500

8. Moisture pick-up
The moisture regain of ZYLON® at 20C, 65%RH is 2.0% for AS and 0.6% for HM. The
moisture regain of ZYLON® HM is far less than p-Aramid.

5Zylon ASZylon HMMoisture Regain(%)

420℃
32100204060

Relative Humidity(%)

1580100

9. Miscellaneous
9.1 Compressive strength
The compressive strength of ZYLON® is much less than the tensile strength same aspara-Aramid fiber.
SampleCritical Strain

Tensile Modulus Compressive Strength

(%)

(GPa)

(GPa)

ZYLON AS

0.217

216

0.469

ZYLON HM

0.227

247

0.561

Aramid HM

0.633

118

0.749
(Bending Beam Method)

9.2 Knot and loop strength
Knot and loop strength of ZYLON® is 30-40% of its tensile strength. This is almost thesame as p-Aramid fiber.

Yarn dtex

Knot strength

Loop strength

percentage(%) of tensile strength
ZYLON AS

1110

3245ZYLON HM

1090

26349.3 Thermal expansion coefficient
Coefficient of thermal expansion of ZYLON® is negative. The dimension along fiber
direction decreases with increasing temperature. CTE of ZYLON®HM is around–6ppm/C.

Dimension(ｘ１０４)

8
ZYLON ASZYLON HM64
20-2-4-120-80-40
Temperature(℃)

16040

9.4 Heat capacity
2.5Zylon ASZylon HMCp (kJ/kgK）

2.0

1.5Data from Toyobo

1.0

Data from OSAKA Univ.

0.5
Dr. Kazuya Saito, et.al., Osaka University
Journal of Polym. Sci., Polym. Phys., Vol.38,
p.15840.00200

400

600

800

Temperature (K)9.5 Abrasion resistance between fiber and metal
Abrasion resistance of ZYLON® is higher than p-Aramid fiber under the same load, butmuch lower than Nylon or high molecular weight polyethylene fiber.
150000120000
90000
60000
30000

17U
H
Mw
PEPo
ly
ester

Nylon6Polyaryl
atepAramidHMZYLONAS0ZYLONCycle to Breakage

Load : 0.9g/dtex

NOTICE:The information in this brochure, to the best of our knowledge, is accurate and correct.
However, Toyobo MC Corporation makes no warranty and assumes no liability
whatsoever in connection with any use of this information. Users determine forthemselves the suitability for their intended use of the material. The brochure is subject torevision as new information becomes available.
The materials are to be stored free from exposure to light, high temperature and humidity.
ZYLON is a registered trademark of Toyobo MC Corporation in Japan.

ZYLON Sales GroupHigh Performance Fibers Sales Section
TOYOBO MC Corporation
Osaka Umeda Twin Towers South,
1-13-1 Umeda, Kita-ku, Osaka City,
Osaka 530-0001 JAPAN
Phone +81-6-6348-3130
Fax +81-6-6348-3413
https://www.toyobo-mc.jp/

F0739K(2023.4)

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