Important features for industrial pipes and fittings out of polypropylene PP - Homopolymer and

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



- 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



- 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



- 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



- 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



- Conclusions

CONTENT



Chemical resistance


Conclusions

CREEP STRENGTH OF PIPE AND FITTING

- Properties

- Creep strength



- 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


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- 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


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


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- Conclusions

Shrinkage behaviour and voidsMachined stub flange out of PPH


- Properties

- Creep strength



- Conclusions

CONTENT



Chemical resistance


Conclusions

CHEMICAL RESISTANCE OF PP

- Properties

- Creep strength



- 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


- Properties

- Creep strength



- Conclusions

Pipe and fitting out of PP with ZnS color pigmentation after the application in a hydrochloric acid pipe system

Chemical resistance of PP


- Properties

- Creep strength



- 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


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


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- Conclusions

Stress crack formation because of temperature loading,

production dependent internal stresses and chemical influence


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- Conclusions

CONTENT



Chemical resistance


Conclusions

RESISTANCE AGAINST SLOW CRACK PROPAGATION

- Properties

- Creep strength



- Conclusions

geometry

sheet

pipe

notch

clamp

clamp

fracture photomicrograph

Test specimen for Full Notch Creep Test (FNCT)

FNCTDescription of the specimen


- Properties

- Creep strength



- 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)


- Properties

- Creep strength



- 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 –


- Properties

- Creep strength



- 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


- Properties

- Creep strength



- Conclusions

CONTENT



Chemical resistance


Conclusions

CONCLUSIONS

- Properties

- Creep strength



- 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



- 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


CONCLUSIONS

- Properties

- Creep strength



- 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


CONCLUSIONS

- Properties

- Creep strength



- 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



- 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



- 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



- Conclusions

CONTENT



Chemical resistance


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!

THANKS FOR YOUR ATTENTION

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Important features for industrial pipes and fittings out of polypropylene PP - Homopolymer and

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