Teflon™ AF

Amorphous Fluoroplastic Resins

Safety in Handling and Use
Introduction
This technical bulletin provides guidelines for the safe
handling and use of Teflon™ AF amorphous fluoroplastic resins.
Temperatures, ventilation, scrap disposal, soldering, andmachining are considered.

Pyrolysis Studies—Weight Loss vs. Temperature
Teflon™ AF resins are thermally stable up to about 360 °C (680°F) in air. Using sensitive analytical techniques, the isothermal
rate of weight loss of Teflon™ AF in air at 360 °C (680 °F) has
been shown to be 0.2–0.6%/hr. Compared with other polymers,
the weight loss rates for Teflon™ AF resins are extremely low andsimilar to rates for Teflon™ FEP.

Decomposition Products
When Teflon™ AF resins are decomposed in air at temperaturesfrom 360–450 °C (680–842 °F), products observed are HF fromreaction of COF2 with moist air, COF2, CO, and hexafluoroacetone(HFA). The amount of HFA evolved upon complete decomposition
at 500 °C (932 °F) is up to 100–200 mg/g of sample.
The OSHA permissible exposure limit for HF is 3 ppm and for
HFA is 0.1 ppm. In animal tests, HFA has been shown to bea potent reproductive and developmental toxin. To protect
against reproductive or developmental hazards from HFA fumes,
Chemours recommends an exposure limit of 0.1 ppm for men andwomen not of childbearing capability, and 0.005 ppm for womenof childbearing capability. A skin notation, denoting that measures
should be taken to protect against significant skin absorption,
applies for HFA hydrates.

Handling Practices
Teflon™ AF resins may contain parts per million of residual HFA.
Because HFA hydrates are readily absorbed through the skin, it isnecessary to avoid skin contact with the resin during processing.
Chemours recommends the use of protective gloves if handling of
the resin is required during manufacturing operations.
Some residual gases (including HF, COF2, CO, and HFA) that
diffuse from Teflon™ AF resins, even at room temperature, may beharmful. Therefore, to avoid exposure, all resin containers shouldbe opened and used only in well-ventilated areas using local exhaust
ventilation (LEV).
In addition, it is recommended that exhaust hoods be installed toremove all of the off-gases released from hot polymers in work areas.
For this purpose, a number of hood designs are shown in Figure 1.
These designs present several alternatives to allow adequate exhaust
volumes for effective capture and removal of all off-gases.
The types of situations normally encountered and the capture
velocities needed to remove all the gases from the local vicinity of
the hot polymer are summarized in Table 1.
The type of work situation is selected from Table 1, and thecenterline velocity required to capture all of the gases is then used tocalculate the volumetric rate of air flow (in m3s/cfm) required for thehood selected from Figure 1. For example, in the extrusion coatingof wire, a capture velocity of 1 m/s (200 fpm) may be needed. A hoodof the plain-opening design with an area of its face of 0.05 m2 (0.5ft2) is placed 0.15 m (0.5 ft) above the discharge face of the extruder.
To remove all the gases generated at the face of this hood, an air
volume of 600 cfm (0.28 m3/s) is needed, as calculated below (notethat all dimensions must be expressed in meters or feet):
Q = V (10X2 + A)
Q = 200 (10 [0.5]2 + 0.5)
Q = 600 cfm
Q = V (10X2 + A)
Q = 1 (10 [0.15]2 + 0.05)
Q = 0.28 m3/s
The importance of locating the hood opening close to the hot
polymer is indicated by the fact that the “X” dimension is raised tothe second power in the above equation. Thus, if this dimension
were doubled in the above example, the volumetric rate of air flow
required would increase to 200 (10 x 12 + 0.5) = 2100 cfm/1.0m3/s, a rise of 250%.

Machining
In grinding, sawing, and machining of Teflon™ AF, measures should
be taken to ensure that temperatures are maintained below 360 °C(680 °F). Generally, coolants are recommended in machining
fluoroplastic resins to improve production rates and quality, and they
can serve to control any tendency toward overheating.

Teflon™ AF

Amorphous Fluoroplastic Resins

Respirable Dust

Scrap Disposal

In any manufacturing or handling operation where dust from Teflon™
AF may be created, the concentration of airborne dust should not
be permitted to exceed the OSHA permissible exposure limits of
5 mg/m3 respirable dust or 15 mg/m3 total dust.

Disposal of scrap Teflon™ AF presents no special problem to the user.
It is best to dispose of such scrap in a landfill dump without burning.

It is strongly recommended that tobacco not be used or carriedin open packs around machining operations or where resin dust
may be encountered, because smoking tobacco contaminatedwith fluoroplastic dust will result in inhalation of toxic thermal
decomposition products.

Soldering and Melt Stripping
The combined effects of temperature, quantity of resin, exposure
time, and ventilation conditions during soldering and melt stripping
are unlikely to produce conditions of toxicological significance.
Any special practices that may be warranted will follow the rules
applicable to any soldering work. For example, prolonged solderingin confined spaces where natural air circulation is restricted will
require mechanical ventilation. The same is true for shop areas
where a number of workers are engaged in soldering or melt
stripping operations. Normal ventilation provided for worker
comfort usually provides adequate safety for these operations. Asan added measure during melt stripping and soldering, many shops
use an exhaust duct at each work station.

Small amounts of scrap, up to approximately 5 kg (10 lb) at
a time, are often incinerated along with general plant refuse.
The incinerator should have sufficient draft to exhaust all
combustion products to the stack. Normal care should be taken
to avoid breathing smoke and fumes from any fire. In addition,
because many polymers produce acids in their combustion
products (in the presence of moisture, decomposition productsof fluoroplastics contain HF), the stack should be highenough to dilute the acid content of the exhaust gases to an
acceptable level. HF causes strong eye and nose irritation before
approaching systemically toxic levels. It is also capable of etching
glass. In addition, vegetation is particularly sensitive to HF. Where
desirable vegetation is present, do not burn scrap fluoroplastics
in an open dump during periods of heavy humidity, fog, or smog.
In the reclamation of metals by melting of scrap, it is advisable
first to remove any nonmetallic components in order to avoid
generating more organic vapors than necessary. The furnace
should have sufficient draft to exhaust all gases to the stack.

Figure 1. Hood Design Data

*Wherever possible, flanges should be provided to eliminate air flow from ineffective zones where no contaminant exists.
Increasing the hood effectiveness in this manner will usually reduce air requirements by 25%. For most applications, theflange width can be equal to the hood diameter or side; but, need not exceed 15 cm (6 in).
**Nomenclature
V = Centerline velocity at X distance from face of hood, m/s (fpm) (use recommended capture velocities from Table 1)
X = Distance from source to face of hood, m (ft)
Q = Air volume, m3/s (cfm)
A = Area at face of hood, m2 (sq ft)
P = Perimeter of work, lin m (lin ft)
D = Height above the work, m (ft)
H = Height of hood, m (ft)
W = Width of hood, m (ft)Amorphous Fluoroplastic Resins

Teflon™ AF

Table 1. Capture Velocities Recommended in Various Work Situations
Dispersion ofContaminants into Air

Capture Velocity,m/s (fpm)

ExamplesReleased with practicallyno velocity into quiet airDrying of fluoroplastic resins—
granular, powder, cubes;
evaporation of solvents, water, etc.

(0.25–0.50)
50–100

Released at low velocity
into moderately still air

Spray coating with solutions.
Normal blending of fluoroplastic
cubes or powders. Molding offluoroplastic resins(0.50–1.0)
100–200

Active generation into zoneof rapid air motion

Melt extrusion of fluoroplastic
resins. Injection and transfer
molding of resins(1.0–2.5)
200–500

Released at high initial
velocity into zone of very
rapid air motion

Grinding and machining of parts
from fluoroplastic resins. Highspeed mixing of fluoroplastic
powders in turbulent mode

(2.5–10.0)
500–2,000

In each category above, a range of capture velocities is shown.
The proper choice of values depends on several factors:
Lower End of Range• Room air current minimal or favorable to capture• Contaminants of low toxicity• Intermittent, low production• Large hood—large air mass in motion

Upper End of Range• Disturbing room air currents• Contaminants of high toxicity• High production, heavy use• Small hood—local control only

HOW TO USE THE TEFLON™ BRAND NAME WITH YOUR PRODUCTTeflon™ is a registered trademark of Chemours for its brand of fluoroplastic resins, coatings, films, and dispersions. The Teflon™ brand name is licensed by Chemours in association with approved applications.
Without a trademark license, customers may not identify their product with the Teflon™ brand name, as Chemours does not sell such offerings with the Teflon™ trademark. Unlicensed customers may refer tothe Chemours product offering with only the Chemours name and product code number descriptor as Chemours sells its product offerings. There are no fair use rights or exhaustion of rights to use the Teflon™
trademark from buying from Chemours, a Chemours customer, or a distributor without a trademark license from Chemours.
If you are interested in applying for a trademark licensing agreement for the Teflon™ brand, please visit www.teflon.com/license
CAUTION: Do not use Chemours materials in medical applications involving permanent implantation in the human body or contact with bodily fluids or tissues, unless the material has been provided fromChemours under a written contract that is consistent with Chemours policy regarding medical applications and expressly acknowledges the contemplated use. For further information, please contact
your Chemours representative. For medical emergencies, spills, or other critical situations, call (866) 595-1473 within the United States. For those outside of the United States, call (302) 773-2000.
The information set forth herein is furnished free of charge and based on technical data that Chemours believes to be reliable. It is intended for use by persons having technical skill, at their own
discretion and risk. The handling precaution information contained herein is given with the understanding that those using it will satisfy themselves that their particular conditions of use present
no health or safety hazards. Because conditions of product use are outside our control, Chemours makes no warranties, express or implied, and assumes no liability in connection with any useof this information. As with any material, evaluation of any compound under end-use conditions prior to specification is essential. Nothing herein is to be taken as a license to operate under or arecommendation to infringe any patents.
NO PART OF THIS MATERIAL MAY BE REPRODUCED, STORED IN A RETRIEVAL SYSTEM OR TRANSMITTED IN ANY FORM OR BY ANY MEANS ELECTRONIC, MECHANICAL, PHOTOCOPYING, RECORDING OR OTHERWISEWITHOUT THE PRIOR WRITTEN PERMISSION OF CHEMOURS.

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Replaces: K-26987
C-10133 (2/16)