Polymeric antistatic additives for thermosetting plastics · 2020-04-02 · Polymeric antistatic...
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Leibniz-Institut für Polymerforschung Dresden Leibniz Gemeinschaft Polymeric antistatic additives for thermosetting plastics 12 Because of their chemical structure plastics are usually insulators with a specific surface resistivity of >10 Ω/o. To avoid electrostatic discharge of polymers, for example in electronic devices or to perform an electrostatic coating process, an antistatic treatment of these plastic components is necessary. There is a demand to lower the specific 6 9 surface resistivity into the range of 10 Ω/o to 10 Ω/o. There are two ways to lower the specific surface resistivity of polymer materials: integration of conductive additives or application of antistatic primer. removing of electrical charges possible removing of electrical charges limited possible removing of electrical charges not possible substances not chargable transitional area substances chargeable conducting electrically discharging insulating 4 5 6 7 8 9 10 11 12 13 14 15 10 10 10 10 10 10 10 10 10 10 10 10 percolated threshold additive concentration percolated area not percolated area surface resistivity [Ohm] Surface resistivity of a polymer with conductive additive State of the art To improve the antistatic properties of polymers usually conductive additives are mixed into the matrix physically. For this, mainly carbon black, but also inorganic pigments, inorganic salts, metal powder or CNT´s are used. Disadvantages by using carbon black n high filling degrees are necessary to exceed the percolation threshold n required high contents result in a reduction of the mechanical material properties n there are problems to disperse the particles homogeneously n the strong coloration of the additive changes the color of matrix extremely Electrical conductivity of solids/ overview (picture: http://www.pro-kunststoff.de)
Transcript of Polymeric antistatic additives for thermosetting plastics · 2020-04-02 · Polymeric antistatic...
Leibniz-Institutfür PolymerforschungDresden
LeibnizGemeinschaft
Polymeric antistatic additives for thermosetting
plastics
12Because of their chemical structure plastics are usually insulators with a specific surface resistivity of >10 Ω/o. To avoid electrostatic discharge of polymers, for example in electronic devices or to perform an electrostatic coating process, an antistatic treatment of these plastic components is necessary. There is a demand to lower the specific
6 9surface resistivity into the range of 10 Ω/o to 10 Ω/o. There are two ways to lower the specific surface resistivity of polymer materials: integration of conductive additives or application of antistatic primer.
removing of electrical charges possible removing of
electrical charges limited possible
removing of electrical charges not possible
substances not chargable
transitional area
substances chargeable
conducting electrically discharging insulating
4 5 6 7 8 9 10 11 12 13 14 1510 10 10 10 10 10 10 10 10 10 10 10
percolated threshold
additive concentration
percolated area
not percolated area
surf
ace
resi
stiv
ity
[Oh
m]
Surface resistivity of a polymer with conductive additive
State of the art
To improve the antistatic properties of polymers usually conductive additives are mixed into the matrix physically. For this, mainly carbon black, but also inorganic pigments, inorganic salts, metal powder or CNT´s are used.
Disadvantages by using carbon black
n high filling degrees are necessary to exceed the percolation thresholdn required high contents result in a reduction of the mechanical material propertiesn there are problems to disperse the particles homogeneouslyn the strong coloration of the additive changes the color of matrix extremely
Electrical conductivity of solids/ overview (picture: http://www.pro-kunststoff.de)
stat
e as
of:
Ju
ly 2
01
9
Contact
Leibniz-Institut für Polymerforschung Dresden e. V.Department Reactive ProcessingDr. Michaela Gedan-SmolkaE-Mail: [email protected] +49 (0)351 4658 448F +49 (0)351 4658 290
Hohe Straße 6 . 01069 Dresden . Germanywww.ipfdd.de
Acknowledgement
Financial support was given by the German Federal Ministry of Education and Research (BMBF 01 RI 0631 B).
Concept: Antistatic treatment with matrix bonded polymeric additives
In order to receive an efficient antistatic treatment and to prevent the migration to the surface, oligomer/polymer based additives as well as a reactive bonding are of advantage.E.g. unsaturated, oligomer/polymer-based antistatic additives with ionic units were developed for SMC. During the thermal molding forms covalent bonds with the polymer matrix. is matrix-compatible and Additive II Additive Ihomogeneously distributed by physical mixing.
O
O
O
O
NR3
O
O
O
NR3
OX
X
nAdditiv I
O
O
O
ONR3
X O
O
O
NR 3X
nAdditiv II
Polymer-based antistatic additives for SMC
1E7
1E8
1E9
1E10
1E11
spe
cifi
c su
rfac
e r
esi
stiv
ity [W
/o]
additive conzentration [Gew.-%]
Additiv I TK
Additiv I NK
Additiv II TK
Additiv II NK
5 10 15 20
Specific surface resistivity of SMC in the presence of (compatibilized and physically mixed) and Additive I Additive II (covalently bonded), (DC: dry climate, NC: normal climate)
Conclusion:
The reactive bonding of oligomeric/polymeric additive to the thermosetting matrix is strictly necessary for an efficient antistatic treatment.
Electrostatic powder coating application on SMC with / without antistatic treatment
SMC before powder coating application SMC after powder coating application
Left/ each: SMC without additive, right: SMC with 3.0 % w/w Additive II
Dr. Katrin SchubertE-Mail: [email protected]
+49(0)351 4658 577P +49(0)351 4658 290F
Innovative advantages of oligomeric/polymeric additives
n high compatibility with the polymer matrix n high permanency by chemical bonding with the matrixn high thermal stability under processing conditionsn colorlessn no negative impact on mechanical material propertiesn less expensive
