Modified Fine Cut – FCM-20, FCM-25

HaloPolymer modified PTFE grades FCM are granular powder products designed for general purpose compression molding. These fully fluorinated resins have the same applications as conventional PTFE but feature improved electrical, mechanical properties and reduced porosity.

Product overview:

Granular modified PTFE have improved mechanical properties in combination with reduced permeability and porosity and improved flex life in critical applications like bellows, diaphragms.

Typical applications:

FCM – 20 allows to achieve higher mechanical properties in combination with reduced permeability and porosity and improved flex – life in critical applications like bellows, diaphragms. It is also a material for compounds production and general molding applications.

Technical and Application Assistance:

FCM – 25 is designed for big billets production. Higher melt viscosity allows to prevent distortion and deformation of articles and billets during sintering.

Availability:

25 kg cardbox with 2×12.5 kg polyethylene inserts.

TYPICAL PROPERTIES OF PTFE GRADES FCM – 20, FCM – 25

 

 

 

Typical Value,

Typical Value,

Properties

Test Method

Units

FCM – 20

FCM – 25

ASTM Type/Grade

ASTM D4894

III

III

Bulk density

ASTM D4894

g/l

460

460

Average particle size (d50)

Internal, Laser

Scatt.

µm

20

20

Mould shrinkage

ASTM D4894

%

5.1

5.5

Std. specific gravity (SSG)

ASTM D4894

kg/m3

2.16

2.16

Tensile strength

ASTM D4894

MPa (psi)

30

30

Elongation at brake

ASTM D4894

%

350

320

Electric Breakdown

Internal

KV/mm

125

115

CERTIFICATION

Certificate of conformity FDA 21 CFR 177.1380 & FDA 21 CFR 177.1550

PTFE

Intertek
Polychemlab

USA

Certificate of conformity Class VI acc. USP 35 <88>

PTFE

Pacific BioLabs

USA

Declaration of Compliance commission reg. (EU) 10/2011

PTFE

SGS Multilab

EU

PRODUCT DESCRIPTION

Modified PTFE granular fine cut powder grades FCM – 20 and FCM – 25 are products of suspension polymerization of TFE performed with a small amount of modifier. These grades can be used for production of a variety of general purpose articles by compression molding techniques.

PROCESSING BASICS

Conventional plastics processing techniques are not suitable for PTFE resin processing due to its high melting temperature and very high melt viscosity.

Grade FCM – 20(25) fabrication includes mould pressing of PTFE powder at ambient temperature, preform sintering in several stages with the maximum temperature of 365°C and subsequent controlled cooling. Billets can be further processed into finished articles by machining or cutting.

STORAGE AND HANDLING

Bags with PTFE powder should be stored in a cold dry place. Recommended storage temperature range is 15-20°C. Bags with powder stored below this range should be kept closed until warmed to room temperature. Optimal temperature range for PTFE compression moulding is 20-25°C. Below this temperature PTFE changes its crystalline structure with volume variation of 1-2%, causing formation of cracks in preforms.

Mechanical manipulations with PTFE powders should be reduced. At the temperature higher than 30°C PTFE tends to form clumps.

PTFE powders attract dust and moisture from ambience and should be processed at clean and dry conditions.

Sintering of PTFE is associated with emission of toxic gaseous products. Therefore sintering process should be performed in a ventilated area. Air from the processing zone must be evacuated.

PRESSING

The pressing process of PTFE powder requires careful powder de-clumping. Uniform layer-by-layermold filling is essential to avoid cracks formation in preform. The temperature of PTFE powder should be kept above 19°C.

Mold filled with PTFE powder is pressed into a solid preform with density of 1.80-2.00 kg/l. Compression ratio parameter indicates volume compaction

of powder during the pressing process. It is based on a preform/bulk density ratio. The rate of ram travel is adjusted to allow air to leave preform.

TYPICAL MOLDING PROPERTIES

Properties

FCM – 20, FCM – 25

Bulk density, g/l

460

Compression ratio

~4

Molding pressure, MPa

20

SINTERING

The preformed PTFE powder is sintered under a temperature program generally containing 7 temperature steps including:

  • heating,
  • dwell before melting,
  • complete melting of a billet,
  • dwell above melting point,
  • cooling to crystallization point,
  • crystallization of the melt of PTFE,
  • final cooling.

Annealing steps are also required for bigger billets sintering in order to reduce article distortion.

MACHINING

PTFE billets are machined in the same way that mild metals are. Sharp steel cutting tools are suitable for the machining process. PTFE billets designed for further skived films production are processed at elevated temperatures.

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