PTFE Reinforcement with P84 Polyimide Compounds | High Performance Polymers

 

P84®
PTFE/Polyimide Compound

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PTFE/P84 Compounds

The reinforcement of PTFE with High performance Polymers has many advantages compared to inorganic fillers. The most important properties are the excellent wear behavior without abrasion of the sliding partner. P84 powders are an active filler in PTFE. This is shown by a highly increased creep resistance and a real bonding of the powder into the matrix.

The development of extremely fine powders lead to excellent surfaces of machined parts and skived films of these compounds.

Due to experiences in different applications, a number of compositions were developed:

93% PTFE / 7% P84
for lip-seals, packings, and spring-reinforced dynamic seals.
85% PTFE / 15% P84
for rod packings, rider and piston rings in compressor applications. Approved in "bone-dry" gas compressors as a piston and rider ring. Skived films as gliding surfaces on several machinery elements, especially in textile equipment.
80% PTFE / 20% P84
for bearings and gliding elements in highly stressed applications. Sealing bands for rotating equipments in compressors and pumps.
75% PTFE / 20% P84 / 5% Graphite
for piston rings in pumps and compressors for dry gases. Gliding elements in weaving machines.
60% PTFE / 40% P84
This hot-molded composition is used in high-load bearings and sealants in machining equipments and as guidance material in mechanical end-uses.
Paste Compounds
Containing 10% - 15% P84 for push-pull cable inner-liners to maintain long service life without any additional lubrication.

Applications

Application Type of compound used Replaced material
Compressor parts piston and rider rings in bone dry applications 85/15 and 80/20 compounds PEEK composites, PTFE/bronze and PTFE/carbon/graphite compounds
Hydraulic seals, spring reinforced and others 93/7 and 90/10 compounds PTFE/carbon,PTFE/ bronze and PTFE/EKONOL
Dynamic seals in air components 80/20 and 85/15 P1 PE/carbon compounds, rubber and PUR seals
Sealing bands for turbo charger 80/20 comp. PTFE/bronze and PTFE/bronce/MoS2 compounds
Sealing bans for shock absorbers 75/20/5 compound Most of avaiable other PTFE compounds tested
Sliding liner for multilayer bearings in automotive applications 75/25 and 75/20/5 compounds, standard and paste types PTFE/MoS2 and PTFE/lead compounds
Innerliner for push-pull cables proprietary paste compound PTFE/glass types, PTFE/PPS compounds
Guidance films for pistons and gliding compopnents, esp. in weaving equipment 85/15 compound with P84 - 1200 mesh also with NPA additives RULON



PTFE/P84 Compounds

93% PTFE - 7% P84

Property Unit  
Color   dark yellow
Spec. Gravity g/cm3 1.97-2.00
Mechanical    
Hardness SHORE D/15 sec 59-62
Tensile N/mm2 / psi 20-23/2900-3200
Elongation % 200-300
Deformation 2000 psi    
24 hrs, RT % 5.0
Deformation 600 psi    
24 hrs, 500 F/260°C % 6.3
Deformation 2000 psi    
24 hrs, 212 F/100°C %  
Thermal expansion    
50-150°C/120-300°F 10-5*K-1 5.9
Tribological properties    
K-Factor at PV 45.000 10-6in3/lb*mi  
Dyn. coeff. of friction
pin and disk method:
   
thrust washer:   0.13
Moulding kg/cm2/psi 250-300/3600-5000
Sinter Conditions Temp. °C/°F 370/695



PTFE/P84 Compounds

85% PTFE - 15% P84

Property Unit  
Color   dark yellow
Spec. Gravity g/cm3 1.87-1.90
Mechanical    
Hardness SHORE D/15 sec 59-63
Tensile N/mm2 / psi 18-20/2600-2900
Elongation % 180-250
Deformation 2000 psi    
24 hrs, RT % 5.1
Deformation 600 psi    
24 hrs, 500 F/260°C %  
Deformation 2000 psi    
24 hrs, 212 F/100°C %  
Thermal expansion    
50-150°C/120-300°F 10-5*K-1 5.9
Tribological properties    
K-Factor at PV 45.000 10-6in3/lb*mi  
Dyn. coeff. of friction
pin and disk method:
   
thrust washer:   0.13
Moulding kg/cm2/psi 250-300/3600-7250
Sinter Conditions Temp. °C/°F 365/690



PTFE/P84 Compounds

80% PTFE - 20% P84

Property Unit  
Color   dark yellow
Spec. Gravity g/cm3 1.8-1.85
Mechanical    
Hardness SHORE D/15 sec 60-65
Tensile N/mm2 / psi 14-18/2030-2500
Elongation % 150-200
Deformation 2000 psi    
24 hrs, RT % 3.5-4.0
Deformation 600 psi    
24 hrs, 500 F/260°C %  
Deformation 2000 psi    
24 hrs, 212 F/100°C % 7.4
Thermal expansion    
50-150°C/120-300°F 10-5*K-1 5.6
Tribological properties    
K-Factor at PV 45.000 10-6in3/lb*mi 2.1
Dyn. coeff. of friction
pin and disk method:
  0.20-0.22
thrust washer:   0.12
Moulding kg/cm2/psi 350-500/5000-7250
Sinter Conditions Temp. °C/°F 360/680



PTFE/P84 Compounds

75% PTFE - 20% P84 - 5% Graphite

Property Unit  
Color   light gray
Spec. Gravity g/cm3 1.78/1.82
Mechanical    
Hardness SHORE D/15 sec 60-65
Tensile N/mm2 / psi 13-16/1885-2320
Elongation % 150-200
Deformation 2000 psi    
24 hrs, RT % 3.5-4.0
Deformation 600 psi    
24 hrs, 500 F/260°C %  
Deformation 2000 psi    
24 hrs, 212 F/100°C % 7.2
Thermal expansion    
50-150°C/120-300°F 10-5*K-1 5.9
Tribological properties    
K-Factor at PV 45.000 10-6in3/lb*mi 1.43
Dyn. coeff. of friction
pin and disk method:
  0.22
thrust washer:    
Moulding kg/cm2/psi 350-500/5000-7250
Sinter Conditions Temp. °C/°F 360/680



PTFE/P84 Compounds

75% PTFE - 20% P84 - 5% Graphite

Property Unit  
Color   dark yellow
Spec. Gravity g/cm3 1.72 (compr. cooled)
Mechanical    
Hardness SHORE D/15 sec 69
Tensile N/mm2 / psi 8-15/1160-2175
Elongation % 10-100
Deformation 2000 psi    
24 hrs, RT % 2
Deformation 600 psi    
24 hrs, 500 F/260°C %  
Deformation 2000 psi    
24 hrs, 212 F/100°C % 5.1
Thermal expansion    
50-150°C/120-300°F 10-5*K-1 6-8
Tribological properties    
K-Factor at PV 45.000 10-6in3/lb*mi  
Dyn. coeff. of friction
pin and disk method:
   
thrust washer:    
Moulding kg/cm2/psi 350-750/5000-10800
Sinter Conditions Temp. °C/°F 345/625



Unfilled PTFE

Property Unit ASTM Method  
Specific Gravity   D 792-66 2.17
Tensile Strength psi/N/mm2 D1708-79 3,400/23
Elongation % D1708-79 350
Deformation      
@ 70°F, 2000 psi 24 hrs     16.7
  Total Deformation % D621-64 8.4
  Permanent Deform.      
@ 500°F, 600 psi 24 hrs     32.6
  Total Deformation % D621-64 19.2
  Permanent Deform.      
Flexural Strength      
@ 1% Strain psi/N/mm2 D700-80  
@ 3% Strain      
@ 1% Strain, 480°F psi/N/mm2 D700-80  
@ 3% Strain, 480°F      
Flexural Modulus psi x 10E3 D700-80 0.97
Compressive Strength      
@ 0.2% Offset psi/N/mm2 D695-80 1,150/7,9
@ 5 % Offset     700/4,8
Compressive Modulus psi x 10E4 D895-80 6.0
Hardness Shore D   51
Coefficient of Thermal Exp.      
@ 78 to 200°F in/in/ D696-79 6.81
@ 78 to 300°F °F x 10E-5   7.04
@ 78 to 400°F     7.60
@ 78 to 500°F     9.12
Thrust Washer Test      
Limiting PV      
(a) 110 ft/min     1,200
(b) 1100 ft/min     1,800
(c) 11000 ft/min     2,500
Wear Factor K x 10E3   2,500
Coefficient of Friction      
(a) Static @ 33.33 psi     0.08
(b) Dynamic 0 33.33 psi, 150ft/min     0.16



85% PTFE / 15% P84

Property Unit ASTM Method  
Specific Gravity   D 792-66 1.82
Tensile Strength psi/N/mm2 D1708-79 1,600/11
Elongation % D1708-79 175
Deformation      
@ 70°F, 2000 psi 24 hrs     8.25
  Total Deformation % D621-64 5.10
  Permanent Deform.      
@ 500°F, 600 psi 24 hrs     23.7
  Total Deformation % D621-64 12.1
  Permanent Deform.      
Flexural Strength      
@ 1% Strain psi/N/mm2 D700-80 1,300/9
@ 3% Strain     2,175/15
@ 1% Strain, 480°F psi/N/mm2 D700-80 174/1,2
@ 3% Strain, 480°F     377/2,6
Flexural Modulus psi x 10E3 D700-80 1.31
Compressive Strength      
@ 0.2% Offset psi/N/mm2 D695-80 1,250/8,6
@ 5 % Offset     1,100/7,5
Compressive Modulus psi x 10E4 D895-80 9.8
Hardness Shore D   60
Coefficient of Thermal Exp.      
@ 78 to 200°F in/in/ D696-79 5.40
@ 78 to 300°F °F x 10E-5   5.90
@ 78 to 400°F     6.40
@ 78 to 500°F     7.20
Thrust Washer Test      
Limiting PV      
(a) 110 ft/min     12,000
(b) 1100 ft/min     13,000
(c) 11000 ft/min     13,000
Wear Factor K x 10E3   2
Coefficient of Friction      
(a) Static @ 33.33 psi     0.08
(b) Dynamic 0 33.33 psi, 150ft/min     0.13



40% PTFE / 55% Bronze / 5% MoS2

Property Unit ASTM Method  
Specific Gravity   D 792-66 3.62
Tensile Strength psi/N/mm2 D1708-79 2,000/13,5
Elongation % D1708-79 110
Deformation      
@ 70°F, 2000 psi 24 hrs     4.6
  Total Deformation % D621-64  
  Permanent Deform.      
@ 500°F, 600 psi 24 hrs     11.0
  Total Deformation % D621-64  
  Permanent Deform.      
Flexural Strength      
@ 1% Strain psi/N/mm2 D700-80 2,100/14,4
@ 3% Strain     2,300/15,8
@ 1% Strain, 480°F psi/N/mm2 D700-80  
@ 3% Strain, 480°F      
Flexural Modulus psi x 10E3 D700-80 2.1
Compressive Strength      
@ 0.2% Offset psi/N/mm2 D695-80 1,800/12,4
@ 5 % Offset     3,000/20,5
Compressive Modulus psi x 10E4 D895-80 11.20
Hardness Shore D   63
Coefficient of Thermal Exp.      
@ 78 to 200°F in/in/ D696-79 5.40
@ 78 to 300°F °F x 10E-5   5.80
@ 78 to 400°F     7.50
@ 78 to 500°F     9.00
Thrust Washer Test      
Limiting PV      
(a) 110 ft/min     10,500
(b) 1100 ft/min     12,000
(c) 11000 ft/min     10,000
Wear Factor K x 10E3   5
Coefficient of Friction      
(a) Static @ 33.33 psi     0.07
(b) Dynamic 0 33.33 psi, 150ft/min     0.13



40% PTFE / 60% Bronze

Property Unit ASTM Method  
Specific Gravity   D 792-66 3.78
Tensile Strength psi/N/mm2 D1708-79 2,000/13,5
Elongation % D1708-79 90
Deformation      
@ 70°F, 2000 psi 24 hrs     5.3
  Total Deformation % D621-64 2.3
  Permanent Deform.      
@ 500°F, 600 psi 24 hrs     8.4
  Total Deformation % D621-64 4.0
  Permanent Deform.      
Flexural Strength      
@ 1% Strain psi/N/mm2 D700-80 2,000/13,8
@ 3% Strain     3,200/22
@ 1% Strain, 480°F psi/N/mm2 D700-80  
@ 3% Strain, 480°F      
Flexural Modulus psi x 10E3 D700-80 1.97
Compressive Strength      
@ 0.2% Offset psi/N/mm2 D695-80 1,740/12
@ 5 % Offset     1,170/8
Compressive Modulus psi x 10E4 D895-80 11.40
Hardness Shore D   65
Coefficient of Thermal Exp.      
@ 78 to 200°F in/in/ D696-79 4.38
@ 78 to 300°F °F x 10E-5   4.37
@ 78 to 400°F     4.99
@ 78 to 500°F     5.72
Thrust Washer Test      
Limiting PV      
(a) 110 ft/min     10,000
(b) 1100 ft/min     12,500
(c) 11000 ft/min     13,000
Wear Factor K x 10E3   5
Coefficient of Friction      
(a) Static @ 33.33 psi     0.07
(b) Dynamic 0 33.33 psi, 150ft/min     0.13



75% PTFE / 20% Glass / 5% MoS2

Property Unit ASTM Method  
Specific Gravity   D 792-66 2.27
Tensile Strength psi/N/mm2 D1708-79 2,375/16
Elongation % D1708-79 240
Deformation      
@ 70°F, 2000 psi 24 hrs     7.1
  Total Deformation % D621-64 3.9
  Permanent Deform.      
@ 500°F, 600 psi 24 hrs     10.9
  Total Deformation % D621-64 0.8
  Permanent Deform.      
Flexural Strength      
@ 1% Strain psi/N/mm2 D700-80 1,350/9,3
@ 3% Strain     2,250/15,5
@ 1% Strain, 480°F psi/N/mm2 D700-80  
@ 3% Strain, 480°F      
Flexural Modulus psi x 10E3 D700-80 2.41
Compressive Strength      
@ 0.2% Offset psi/N/mm2 D695-80 1,810/12,5
@ 5 % Offset     1,100/7,5
Compressive Modulus psi x 10E4 D895-80 11.9
Hardness Shore D   58
Coefficient of Thermal Exp.      
@ 78 to 200°F in/in/ D696-79 3.51
@ 78 to 300°F °F x 10E-5   3.55
@ 78 to 400°F     3.85
@ 78 to 500°F     4.45
Thrust Washer Test      
Limiting PV      
(a) 110 ft/min     12,300
(b) 1100 ft/min     12,500
(c) 11000 ft/min     15,500
Wear Factor K x 10E3   6
Coefficient of Friction      
(a) Static @ 33.33 psi     0.06
(b) Dynamic 0 33.33 psi, 150ft/min     0.08



67% PTFE / 33% Carbon-Graphite

Property Unit ASTM Method  
Specific Gravity   D 792-66 2.05
Tensile Strength psi/N/mm2 D1708-79 1,800/12,5
Elongation % D1708-79 90
Deformation      
@ 70°F, 2000 psi 24 hrs     11.3
  Total Deformation % D621-64 6.0
  Permanent Deform.      
@ 500°F, 600 psi 24 hrs     18.0
  Total Deformation % D621-64 13.0
  Permanent Deform.      
Flexural Strength      
@ 1% Strain psi/N/mm2 D700-80 1,200/8,2
@ 3% Strain     1,950/13,4
@ 1% Strain, 480°F psi/N/mm2 D700-80  
@ 3% Strain, 480°F      
Flexural Modulus psi x 10E3 D700-80 1.70
Compressive Strength      
@ 0.2% Offset psi/N/mm2 D695-80 1,700/11,7
@ 5 % Offset     900/6,2
Compressive Modulus psi x 10E4 D895-80 11.0
Hardness Shore D   63
Coefficient of Thermal Exp.      
@ 78 to 200°F in/in/ D696-79 4.70
@ 78 to 300°F °F x 10E-5   4.90
@ 78 to 400°F     5.30
@ 78 to 500°F     6.20
Thrust Washer Test      
Limiting PV      
(a) 110 ft/min     15,000
(b) 1100 ft/min     20,000
(c) 11000 ft/min     12,500
Wear Factor K x 10E3   5
Coefficient of Friction      
(a) Static @ 33.33 psi     0.08
(b) Dynamic 0 33.33 psi, 150ft/min     0.09



Creep under Load




Dynamic Coefficient of Friction at Room Temperature After 16 hrs




Static Coefficient Of Friction at Room Temperature After 16 hrs




K-Factors on Different Sliding Surfaces




K-Factors on Steel at Different Temperatures




Tribological Properties of Polymer Filled PTFE Compounds Against Steel 100 Cr6




Abrasion of Sliding Counterparts




Test Report

Material:     PTFE/P84
Description 60% MICA filled PTFE 80/20 60/40
Test Results:        
  Unit      
Density: g/cm3 2.30 1.85 1.72
         
Tensile psi 842.7 2170 1450
Elongation % 31 150-200 10-30
Creep 2000 psi, 100°C(212°F), 24 hrs % 3.3 7.4 5.1
Creep 600 psi, 260°C(500°F), 24 hrs %      
Compressive Strength 1% Deform. psi 194,3 239,25 313,2
Compressive Strength 10% Deform. psi 3488,7 2657,85 3674,3
         
Linear Thermal Expansion        
TMA 120-300°F in/in*K 2 5 - 6 6 - 8
K-Factor PV 12.000 - RT 10^-10in. min/lb. ft. hr 133,77 21,5 36,26
  10A- 3 mm3/Nkm 2,73 0,44 0,74
Static Coeff.of Friction   0,25 0,21 0,27
Dynamic Coeff of Friction   0,25 0,14 0,36



Comparison Testing

PTFE / 10% EKONOL

Material Method Unit  
       
Particle Size ASTM Sieve mesh -325
       
Tensile ASTM D1708 psi 4190
Elongation ASTM D1708 % 312
       
Hardness ASTM (3sec) SHORE D 62
Density   g/cm3 2,07
       
K-Factor PV 12.000
on Steel 100 Cr6/RT
10^-10 in3.min/ft.lb.hr 165
Static Coeff. of Friction   0,15
Dynamic Coeff. of Friction   0,29
     
K-Factor PV 12.000
on Steel 100 Cr6/180°C
10^-10 in3.min/ft.lb.hr 261



Comparison Testing

PTFE / 10% PPS

Material Method Unit  
       
Particle Size ASTM Sieve mesh -325
       
Tensile ASTM D1708 psi 2870
Elongation ASTM D1708 % 243
       
Hardness ASTM (3sec) SHORE D 62
Density   g/cm3 2,03
       
K-Factor PV 12.000
on Steel 100 Cr6/RT
10^-10 in3.min/ft.lb.hr 38,7
Static Coeff. of Friction   0,23
Dynamic Coeff. of Friction   0,15
     
K-Factor PV 12.000
on Steel 100 Cr6/180°C
10^-10 in3.min/ft.lb.hr 154



Comparison Testing

PTFE / 10% P84

Material Method Unit  
       
Particle Size ASTM Sieve mesh -325
       
Tensile ASTM D1708 psi 3610
Elongation ASTM D1708 % 261
       
Hardness ASTM (3sec) SHORE D 62
Density   g/cm3 2,02
       
K-Factor PV 12.000
on Steel 100 Cr6/RT
10^-10 in3.min/ft.lb.hr 29,4
Static Coeff. of Friction   0,18
Dynamic Coeff. of Friction   0,19
     
K-Factor PV 12.000
on Steel 100 Cr6/180°C
10^-10 in3.min/ft.lb.hr 52,4



Structure of Polymer Filled PTFE




Processing

PTFE/P 84 compounds require slightly higher moulding pressures than virgin PTFE. With P 84 loadings of more than 20 % the moulding pressure is twice the pressure of standard PTFE. This high compaction is required to obtain a maximum on density and hardness. Also the porosity is influenced. The compaction speed should be slower than standard compounds because of the micro-porous structure of P 84. The moulded billets should be stored in air overnight to enable the release of compressed air.

The sintering of high loaded compounds requires modified sintering temperatures over virgin PTFE. High temperatures up to 370 °C (700 °F) lead to a maximum in hardness and better tribological results. But this temperature must not be exeeded. More than 20 % P 84 powder needs to be sintered at lower temperatures (see table for conditions). Loadings of more than 30 % by wt. of P 84 requires hot moulding conditions at a maximum temperature of 345 °C (653 °F).

The mechanical properties are strongly affected by the base PTFE resin. Fine PTFE particles as offered by ICI's G163 and MONTEDISON's Algoflon F5 offer a maximum on elongation and strength. But due to reasons like snap back behavior or more bulk density - to mould bigger parts for skiving into films - all of the other PTFE types are acceptable.

To offer extremely low porosity and smooth machined surfaces, P 84 is available in different grain sizes. For technical parts i.e. bearings, gliding elements and piston rings, P 84 -325 mesh is used. For skived films and dynamic seals -425 mesh and -1200 mesh is offered. The discoloration of the outside section will be reduced with finer particles.

Skiving should be done with preheated blocks up to 150 °C or 300 °F. This guarantees best surface qualities.

Direct forming with PTFE/P 84 compounds is easy to maintain. Sintering should be done under inert conditions to avoid discoloration of the sintered parts.

Ram-extrusion requires absolutely dry handling of the compound. Due to the hygroscopic behavior of P 84, fast humidity pick up is possible. It is neccessary to use closed hoppers and feeding systems. Only a very small portion of granulated material should be in the cone upside the barrel. High brake forces are needed, which can only be maintained by hydraulic or mechanical brakes. Pneumatic brakes cannot be used.

The maximum barrel-temperature must not exeed 380 °C (715 °F).

If uncontrolled feeding or porosity occures predry the granulated material at 120 °C (250 °F) for 12 hours.

Take care on the desiceant pack which sould always be inside the container.

An easy start up with P 84 in extrusion would be with presintered grades which are not as hygroscopic as free flow compounds. Later on we recommend the use of free flow grades because of better mechanical properties and more homogenious structure but added care should be taken to minimize the moisture absorption before processing.