Important features for industrial
pipes and fittings out of polypropylene
PP - Homopolymer and
PP - Copolymer
Description and general properties
Creep strength of pipe and fitting
Chemical resistance
Resistance against slow crack Propagation
Conclusions
CONTENT
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
• high creep strength
• very good chemical resistance
• resistance against microorganisms
• high heat reversion resistance
• very good abrasion properties
• good weldability
• no deposits / no increments
• excellent acoustic damping characteristics
• very good thermoformable
PP-H, PP-B and PP-R
GENERAL PROPERTIES
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
PP-H (Polypropylene Homopolymer)The Homopolymer consists of macro-molecules, which are built of only one polymer:
P - P - P - P - P - P - P - P - P - P
PP-B (Polypropylene Block Copolymer)The Block Copolymer consists of macro-molecules, where Ethylene is included in block form up to 12 % (standard < 7%):
P - P - P - P + P - P - E - E - P - P - P - E
PP-R (Polypropylene Random Copolymer)The Random Copolymer is built of molecules, where a certain content (2-7%) if Ethylene is embedded statically distributed:
E - P - E - P - P - P - E - P - P - P
PP-TypesGeneral description
GENERAL PROPERTIES
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
PP in comparisonCrystal structure
PP-Homopolymer with rough sperulitic
super lattices (PP-H a-nucleated)
PP-Homopolymer with fine crystallic
structure (PP-H b-nucleated)
PP-Random Copolymer with fine crystallic
structure
GENERAL PROPERTIES
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Characteristics PP-H PP-R
welding quality - good - excellent
exception: bending angle accord. to DVS 2203 part 5
- bending angle varies when welding PPH together with PPH,PPB and also generally significant lower than PPR
- bending angle > 160 deg. with also when welding PPR together with PPH,PPB,PPR
chemical resistance
- good - good
NaOH (40% / 80°C)lower resistant - higher resistant
Cm-factor
1,6
The allowable working pressure is
Lower than for PPR
- 1,25- related to the very
good impact resistance
PP in comparisonGeneral properties / part 1
GENERAL PROPERTIES
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Characteristics PP-H PP-R
voids (of fittings) increasing risk of voids good processibility
E-modulus (stiffness)
higher E-modulus =>
support distance higher
lower E-modulus =>
support distance lower
impact strengthlower impact strength
applicable only for temp. > 5°C
higher impact strength
applicable for temp. < 0°C
minimum temp. limit
approx. +5°C approx. -5°C
stress-relaxationlow relaxation of stress
because of higher
creep-modulus
fast relaxation of stress
because of lower
creep-modulus
GENERAL PROPERTIES
PP in comparisonGeneral properties / part 2- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
CONTENT
Description and general properties
Creep strength of pipe and fitting
Chemical resistance
Resistance against slow crack Propagation
Conclusions
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Creep behaviour of pipes out of PPacc. to DIN 8077 PP-H and PP-R
0,1 1,0 10 10 2 10 3 10 4 10 5 10 60,5
0,6
0,7
0,8
0,91,0
2,0
3,0
4,0
5,0
6,0
7,0
8,0
9,010,0
20,0
30,0
40,0
50,0
Standzeit [h]
1 10 25 50
Standzeit [Jahre]
Ver
gle
ich
spa
nnun
g v
[N/m
m2
]
20°C
40°C
60°C
70°C
80°C
95°C
100
10°C
30°C
50°C
90°C
0,1 1,0 10 10 2 10 3 10 4 10 5 10 60,5
0,6
0,7
0,8
0,91,0
2,0
3,0
4,0
5,0
6,0
7,0
8,0
9,010,0
20,0
30,0
40,0
50,0
Standzeit [h]
1 10 25 50
Standzeit [Jahre]
Ver
gle
ich
spa
nnun
g v
[N/m
m2
]
20°C
40°C
80°C
100
10°C
30°C
50°C
60°C
70°C
95°C90°C
PP-HPP-H PP-RPP-R
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
0,1 1,0 10 102 103 104 105 1061,0
2,0
3,0
4,0
5,0
6,0
7,0
8,0
9,0
10,0
Time to fail [h]
1 10 25 50
Time to fail [years]
100
PP-H
PP-B
PP-R
Hoo
p st
ress
[N
/mm
]v
2
Creep behaviour of pipes out of PPacc. to DIN 8077 at 60°C
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
0,1 1,0 10 102
103
104
105
106
0,5
0,6
0,7
0,8
0,91,0
2,0
3,0
4,0
5,0
6,0
7,0
8,0
9,0
10,0
Time to fail [h]
1 10 25 50
Time to fail [years]
100
PP-H
PP-B
PP-R
Hoo
p St
ress
[
N/m
m ]
v2
Creep behaviour of pipes out of PPacc. to DIN 8077 at 80°C
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
= Safety
factor
1,6 1,4 1,25
1,25
Allo
wed
wor
king
exc
ess
pres
sure
s in
bar
(DIN
807
7)
0
2
4
6
8
10
12
14
16
18
20
10 20 30 40 50 60 70 80 95
Temperature [°C]
PP-H
PP-B
PP-R
Allowed working excess pressureacc. to DIN 8077 for media water
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Back gateBack gateSide gateSide gate Ring gateRing gate
Y-gateY-gate
Stress duration [h]Stress duration [h]log. tlog. t
log
. lo
g. ss
Ho
op
Str
ess
[N
/mm
²]H
oo
p S
tre
ss [
N/m
m²]
Time to fail of injection moulded components / gating system
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
0
1000
2000
3000
4000
5000
6000
7000
Y-gat on PP-R Tee Pin gate on PP-H Tee
Tim
e to
fail
[h]
T = 95 °CSigma = 3,6 N/mm²
T > 1000 h
Time to fail of injection moulded components / creep tests acc. to DIN 8078 tees SDR 11
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Shrinkage behaviour and voidsMachined stub flange out of PPH
CREEP STRENGTH OF PIPE AND FITTING
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
CONTENT
Description and general properties
Creep strength of pipe and fitting
Chemical resistance
Resistance against slow crack Propagation
Conclusions
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
0,00
1,00
2,00
3,00
4,00
5,00
6,00
3 7 14 28 56 84Immersions period in days[d]
01 - PPH natural, - 05 - PPR natural, - 06 - PPR grey, TiO2 03 - PPH grey, TiO2 02 - PPH grey, TiO2
09 - PPB grey, TiO2 07 - PPR grey, TiO2 / ZnS 04 - PPH grey, ZnS 08 - PPR grey, ZnS 10 - PPB grey, ZnS
Wei
gh
t c
han
ges
in
per
cen
t [%
]
Comparison of weight changesPP-molding materials in HCl+MCB+o-DCB at 60°C
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Pipe and fitting out of PP with ZnS color pigmentation after the application in a hydrochloric acid pipe system
Chemical resistance of PP
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
0,1 1,0 10 102
103
104
105
106
0,5
0,6
0,7
0,8
0,91,0
2,0
3,0
4,0
5,0
6,0
7,0
8,0
9,010,0
Time to fail [h]
1 10 25 50
Time to fail [years]
Hoo
pe
stre
ss
[
N/m
m ]
v2
100
PP-H
PP-B
PP-R
Chemical resistance of PP
Caustic soda solution 50%, T=80°C,
creep test
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
NaOH 40 % PP-RSpecimen 1
PP-RSpecimen 2
PP-H(-nucleated)
PP-B PP-H(-nucleated)
Times to fail forHS-welded spe-cimen
7546 h 9151 h 4489 h 868 h 1253 h
Times to fail of different PP moulding materials at the
creep test at 80°C in 40% caustic soda solution, test
tension: 5,5 N/mm²
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Stress crack formation because of temperature loading,
production dependent internal stresses and chemical influence
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
• Maximum internal
stresses (tensile) often
appear in the area of the
bead notch
• Due to a loading, an
additional
superimposition of further
stresses results.
• A failure of the
component (welding joint)
starts from the bead
notch.
Internal stresses in the welding zone
CHEMICAL RESISTANCE OF PP
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
CONTENT
Description and general properties
Creep strength of pipe and fitting
Chemical resistance
Resistance against slow crack Propagation
Conclusions
RESISTANCE AGAINST SLOW CRACK PROPAGATION
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
geometry
sheet
pipe
notch
clamp
clamp
fracture photomicrograph
Test specimen for Full Notch Creep Test (FNCT)
FNCTDescription of the specimen
RESISTANCE AGAINST SLOW CRACK PROPAGATION
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
FNCT-results (times to fail) of polypropylene, tested
in water under 2% wetting agent influence (Arkopal N100)
622
397 387
841
267
164
0
100
200
300
400
500
600
700
800
900
1 2 3 4 5 6
Material
t [h
]
PP-R
(Type B)
PP-R
(Type D)
PP-H
(Type S, -nucleated)
PP-H
(-nucleated)
PP-H
(-nucleated)
PP-B
(Type B)
RESISTANCE AGAINST SLOW CRACK PROPAGATION
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
FNCT-results (times to fail) of polypropylene specimen,
tested in water under 2% wetting agent influence
(Arkopal N-100)
Material 80 °C, = 4 N/mm² 95 °C, = 3,5 N/mm²
PP-R (Type B) 841 h –
PP-R (Type D) 622 h 275 h
PP-H (Type S, -N.) 397 h 198 h
PP-H (-N.) 387 h 135 h
PP-H (-N.) 267 h –
PP-B (Type B) 164 h –
RESISTANCE AGAINST SLOW CRACK PROPAGATION
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Currently demanded minimum values in FNCT (times to
fail) for PP-moulding materials (2% Arkopal N-100) from
the DIBt
Material 80°C, = 4 N/mm² 95°C, = 3,5 N/mm²
PP-H 250 h 120 h
PP-B 150 h -
PP-R 500 h 250 h
RESISTANCE AGAINST SLOW CRACK PROPAGATION
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
CONTENT
Description and general properties
Creep strength of pipe and fitting
Chemical resistance
Resistance against slow crack Propagation
Conclusions
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Advantages PP-H
• high creep strength at low temperatures
• higher E-module, larger support
distances are possible
• lower raw material price
PPH, PPB and PPR in comparison
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Advantages PP-B
• better shrinkage behaviour,
therefore no voids and larger
injection moulding parts are possible
• lower internal stress potential
• high viscosity
• very high impact resistance
PPH, PPB and PPR in comparison
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Advantages PP-R
• high creep strength at high temperatures
• higher resistance against slow crack propagation
• higher pressure loadability
• better shrinkage behaviour, therefore no voids
and larger injection moulding parts are possible
• lower internal stress potential
• high viscosity
PPH, PPB and PPR in comparison
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
PP-Homopolymer:
• Semi-finished products for the tank
construction
• Pipes for industrial applications
PP-Block Copolymer:
• Piping systems for sewage water technology
• (underground installations)
PP-Random Copolymer:
• Piping systems for high pressure and temperature loadings
(systems for industrial water use)
• Welding rod
• Injection moulding components (specially in larger
dimensions)
Typical application ranges of PP-types
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
PP-R, black: UV-stabilization because of high content of
carbon black (impact resistance
decreases)
PP-R, natural: High purity applications, as no color
additives are included
PP-H-s:Flame retarding Homopolymer, e.g. for the application
in ventilation, exhaust or chimney systems
PP-R-s-el: Flame retarding Random Copolymer, which is
mostly used for the transport of slightly ignitable
media because of its electrical conductivity
Modified PP-moulding materials
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
Bends 90°out of PP up to d500
in SDR 33, 17,6 and 11
Tees out of PP up to d 500
in SDR 33, 17,6 and 11
Backing rings out of PP/St up to d 630
for max. working excess pressures of 10 bar
Injection moulded components for Pressure piping systems
CONCLUSIONS
- Properties
- Creep strength
- chemical Resistance
- Slow crack Propagation
- Conclusions
CONTENT
Description and general properties
Creep strength of pipe and fitting
Chemical resistance
Resistance against slow crack Propagation
Conclusions
AGRU Kunststofftechnik GmbHIng.-Pesendorfer-Str. 31
A-4540 Bad HallAustria / EU
www.agru.at
T +43 (0) 7258 790 - 0F +43 (0) 7258 3863E [email protected]
Subject to errors of typesetting, misprints and modifications. Illustration are generic and for reference only!
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