PTFE Special Compound

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Special compounds compliment the series of standard “G” compounds.
IPM special compounds are gaining more and more market share due to the increasing demand for solution to high tech industrial applications.
The associated table illustrates the properties of some special “G” compounds by IPM. They represent only a small number of the compounds available among the range of solutions IPM is able to suggest.
Some of IPM compounds include fillers like PEEK, PPS, polyimide, LCP, molybdenum disulphide, etc.
 

SPECIAL COMPOUNDS AVAILABLE


In addition to virgin PTFE G400 products, IPM offers a wide range of compounded products as well. Among these compounds, processed directly in IPM compounding unit starting from selected polymers and special high-purity fillers, end users are enabled to find the right answer to their technical requirements.
To make their selection easier, the following tables resume:

  • the correlation among single fillers, properties and common uses
  • properties of standard and special compounds among those most commonly marketed
The following table shows the way each filler affects physical and mechanical properties.
Combinations of two or more fillers (not considered in the table) allow a large number of compounds. Thus the resulting combined properties offer a variety of applications.
Filler Property Most common applications
Glass Enhanced wear resistance.
Enhanced chemical resistance (except for alkali and hydrofluoric acid).		 Valve seats, seals, bearings, requested to resist sliding and chemicals.
Suitable for bearings working at low PV values.
Graphite Extremely low coefficient of friction. Fairly good compressive strength. Good wear resistance. Bearings for high speed on fairly hard surface.
Carbon Good thermal conductivity.
Good resistance to deformation. 		Valve seats.
Bearings for high speed and when fast dissipation of electric charges is needed.
Elastic bands for unlubricated compressors.
Molibdenum disulphide Enhanced non-stick properties.
Low static coefficient of friction.
Fairly good resistance to deformation.		 Guide bands.
Details needing good resistivity.
Bronze Enhanced compressive strength. Good wear resistance and high thermal conductivity. Anti-extrusion rings.
Unlubricated bearings for high speed on not hard surface.
IPM can offer an extremely wide range of skived tapes, sheets, extruded and moulded rods and tubes, in virgin PTFE as well as compounded from G series.
Dimensions and relevant tolerances are included in the Dimensional Brochure. Tapes, sheets and finished products can be supplied etched.

MAIN PROPERTIES | MOLDED

 
Property
  
u.m.
  
Method
  
G Special Compounds
G416
  
G418
  
G420
  
G427
  
G436
  
G455
  
G456
  Density  
g/cm2
  
ASTM D792
3,05-3,12
2,20-2,30
3,25-3,35
3,15-3,25
2,19-2,24
1,90-2,00
2,05-2,11
  Coefficient of linear thermal expansion  
 
ASTM D696
10-11,5
9-12
10-12
9-12
11-12
6,5-10
8-11
  Hardness Shore D  
Punti
  
ASTM D2240
62-67
55-60
65-70
60-67
50-55
65-70
65-70
  Tensile strength  
N/mm2
  
ASTM D4745
23-28
15-20
17-23
23-28
23-28
8-13
12-16
  Elongation at break  
%
  
ASTM D4745
200-250
220-270
180-230
200-250
230-280
40-70
70-100
  Compressive strengtat 1% deformation  
N/mm2
  
ASTM D695
7-9
8,5-9
10-10,5
6,5-8
5,5-6,5
12-13,5
7-11
  Deformation under load  
%
  
ASTM D621
8-11
7-8
5,5-6,5
6,5-7,5
13-14
4-6
4-5,5
  Permanent deformation (as above, after 24-h relaxation)  
%
  
ASTM D621
3-5
3-4
2-3
3-3,5
5-6
1,2-1,4
1,4-1,9
  Kinetic coefficient of friction  
/
  
ASTM D1894
0,13
0,08
0,13
0,13
0,18
0,12
0,12
  Wear factor at PV 100    
ASTM D3702
9-13
10-20
20-30
10-15
3.000
20-30
12-18


PROPERTIES OF IMPORTANCE FOR DESIGNING

Fillers mixed with PTFE allow to improve some basic physical properties of virgin polymer.
The advantages are the following:

  • enhanced compressive strength
  • enhanced thermal conductivity
  • reduced thermal expansion
  • reduced wear factor
MECHANICAL PROPERTIES
When talking about the material mechanical properties, tensile strength and elongation at break are usually the topics before others.
However, these two properties, though the most common ones, do not always carefully reflect the behavior of the material itself in some applications, while compressive properties are actually the most important ones. We’d highlight compressive strength at a set deformation, deformation under constant load and permanent deformation at a set temperature.
 
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