Brochure: Carbon Additives for Polymer Compounds - Timcal Graphite
Brochure: Carbon Additives for Polymer Compounds - Timcal Graphite
Brochure: Carbon Additives for Polymer Compounds - Timcal Graphite
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<strong>Carbon</strong> <strong>Additives</strong> <strong>for</strong><br />
<strong>Polymer</strong> <strong>Compounds</strong><br />
Conductive <strong>Carbon</strong> Black<br />
<strong>Graphite</strong> & Coke<br />
www.timcal.com<br />
1<br />
<strong>Polymer</strong>s
Who are we?<br />
TIMCAL <strong>Graphite</strong> & <strong>Carbon</strong> has a strong tradition<br />
and history in carbon manufacturing. Its<br />
first manufacturing operation was founded in<br />
1908.<br />
Today, TIMCAL facilities produce and market a<br />
large variety of synthetic and natural graphite<br />
powders, conductive carbon blacks and waterbased<br />
dispersions of consistent high quality.<br />
Adhering to a philosophy of Total Quality Man-<br />
Where are we located?<br />
With headquarters located in Switzerland, TIMCAL<br />
<strong>Graphite</strong> & <strong>Carbon</strong> has an international presence<br />
with production facilities and commercial<br />
offices located in key markets around the globe.<br />
2<br />
WHAT IS ouR vISIon?<br />
HQ Bodio, Switzerland<br />
Graphitization & processing<br />
of synthetic<br />
graphite, manufacturing<br />
of water-based dispersions,<br />
processing of natural<br />
graphite & coke and<br />
manufacturing & processing<br />
of silicon carbide<br />
Baotou, China<br />
Purification, intercalation,<br />
exfoliation, size reduction,<br />
shape modification<br />
and sieving & classifying<br />
of natural graphite<br />
To be the worldwide leader and to be recognized<br />
as the reference <strong>for</strong> innovative capability<br />
in the field of carbon powder-based solutions.<br />
agement and continuous process improvement,<br />
all TIMCAL manufacturing plants comply<br />
with ISO 9001-2008.<br />
TIMCAL <strong>Graphite</strong> & <strong>Carbon</strong> is committed to<br />
produce highly specialized graphite and carbon<br />
materials <strong>for</strong> today’s and tomorrow’s cus-<br />
tomers needs.<br />
TIMCAL <strong>Graphite</strong> & <strong>Carbon</strong> is a member of IMERYS,<br />
a world leader in adding value to minerals.<br />
The Group’s industrial and commercial activities<br />
are managed by an experienced multinational<br />
team of more than 430 employees from many<br />
countries on three continents.<br />
Willebroek, Belgium<br />
Manufacturing & processing<br />
of conductive<br />
carbon black<br />
Changzhou, China<br />
Manufacturing of<br />
descaling agents and<br />
processing of natural<br />
graphite<br />
Lac-des-Îles, Canada<br />
Mining, purification and<br />
sieving of natural<br />
graphite flakes<br />
Fuji, Japan<br />
Manufacturing of<br />
water-based dispersions<br />
Terrebonne, Canada<br />
Exfoliation of natural<br />
graphite, processing of<br />
natural and synthetic<br />
graphite<br />
For the updated list of<br />
commercial offices and<br />
distributors please visit<br />
www.timcal.com
Contents<br />
EnSACo® Conductive <strong>Carbon</strong> Black<br />
TIMREX® <strong>Graphite</strong> and Coke<br />
<strong>Carbon</strong> additives <strong>for</strong> polymer compounds<br />
THE pRoduCTS<br />
• Introduction to ENSACO® Conductive <strong>Carbon</strong> Black p. 4<br />
• Introduction to TIMREX® <strong>Graphite</strong> and Coke p. 5<br />
• ENSACO® Conductive <strong>Carbon</strong> Black <strong>for</strong> polymer compounds p. 6<br />
• TIMREX® <strong>Graphite</strong> and Coke <strong>for</strong> polymer compounds p. 8<br />
TYpICAL AppLICATIonS FoR EnSACo® ConduCTIvE CARBon BLACk<br />
• Electrically conductive plastics p. 10<br />
• Rubber p. 14<br />
• Power cables and accessories p. 17<br />
TYpICAL AppLICATIonS FoR TIMREX® GRApHITE And CokE<br />
• Self lubricating polymers p. 18<br />
• Filled PTFE p. 20<br />
• Thermally conductive polymers p. 22<br />
3
the product<br />
Introduction to EnSACo®<br />
Conductive <strong>Carbon</strong> Black<br />
Conductive carbon blacks are carbon blacks<br />
with high to very high stucture (or void volume)<br />
allowing the retention of a carbon network at<br />
low to very low filler content. The void volume<br />
can originate from the interstices between the<br />
carbon black particles, due to their complex arrangement,<br />
and from the porosity.<br />
HoW EnSACo® ConduCTIvE CARBon<br />
BLACkS ARE pRoduCEd<br />
The <strong>Timcal</strong> carbon black process has been developed<br />
around 1980 and is commercially exploited<br />
since 1982. The plant uses most modern<br />
technology. The process is based on partial oil<br />
oxidation of carbochemical and petrochemical<br />
origin. The major difference with other partial<br />
combustion carbon black technologies lies in<br />
the aerodynamic and thermodynamic conditions:<br />
• low velocity;<br />
• no quench;<br />
• no additives.<br />
This leads to a material with no or nearly no<br />
sieve residue on the 325 mesh sieve and allows<br />
the highest possible purity.<br />
The granulation process has been developed to<br />
achieve an homogeneously consistent product<br />
maintaining an outstanding dispersibility. It is in<br />
fact a free-flowing soft flake characterised by a<br />
homogeneous and very low crushing strength<br />
that guarantees the absence of bigger and<br />
harder agglomerates.<br />
The process enables the production of easily<br />
dispersible low surface area conductive carbon<br />
blacks as well as very high surface area conductive<br />
carbon blacks. The unique combination of<br />
high structure and low surface area also contributes<br />
to give outstanding dispersibility and<br />
smooth surface finish. The low surface area materials<br />
show a chain-like structure comparable<br />
to acetylene black. The very high surface area<br />
materials belong to the Extra Conductive (EC)<br />
family. Although ENSACO® <strong>Carbon</strong> Blacks are<br />
slightly more graphitic than furnace blacks, they<br />
are quite close to the latter ones as far as rein<strong>for</strong>cement<br />
is concerned.<br />
ENSACO® <strong>Carbon</strong> Blacks combine to a certain<br />
extent both the properties of furnace and acetylene<br />
black, reaching the optimal compromise.<br />
4<br />
TEM picture of ENSACO® 250 G<br />
<strong>Carbon</strong> Black showing the high<br />
level of aggregation.<br />
By courtesy of University of<br />
Louvain (Louvain-La-Neuve)<br />
STM picture of the surface of<br />
ENSACO® 250 G <strong>Carbon</strong> Black<br />
5x5 nm.<br />
By courtesy Prof. Donnet - Mulhouse<br />
SEM picture of ENSACO® 250 G<br />
<strong>Carbon</strong> Black illustrating the<br />
high void volume.<br />
By courtesy of University of<br />
Louvain (Louvain-La-Neuve)<br />
100 nm<br />
100 nm
Introduction to TIMREX®<br />
<strong>Graphite</strong> and Coke<br />
<strong>Graphite</strong> finds wide application thanks to its<br />
favourable combination of properties such as:<br />
• low friction, chemical inertness and<br />
absence of inherent abrasiveness;<br />
• high thermal conductivity, thermal<br />
stability and electrical conductivity;<br />
• film <strong>for</strong>ming ability on metal surfaces;<br />
• relatively inoffensive nature of both<br />
powders and products of combustion.<br />
These properties are a consequence of the lamellar<br />
graphite structure and the anisotropic<br />
nature of chemical bonding between carbon<br />
atoms. In graphite, three sp 2 hybrid orbitals<br />
(each containing one electron) are <strong>for</strong>med<br />
from the 2s and two of the 2p orbitals of each<br />
SEM picture of TIMREX® <strong>Graphite</strong> showing the perfect<br />
crystalline structure.<br />
Lc<br />
c/2 = Interlayer distance<br />
Lc = Crystallite height<br />
carbon atom and participate in covalent bonding<br />
with three surrounding carbon atoms in the<br />
graphite planes. The fourth electron is located<br />
in the remaining 2p orbital, which projects<br />
above and below the graphite plane, to <strong>for</strong>m<br />
part of a polyaromatic π-system.<br />
Delocalisation of electrons in π-electron system<br />
is the reason of graphite’s high stability<br />
and electrical conductivity. Interlamellar bonding<br />
was once thought to be weak and mainly<br />
the result of Van der Waals <strong>for</strong>ces, however, it<br />
now appears that interlamellar bonding is rein<strong>for</strong>ced<br />
by π-electron interactions. <strong>Graphite</strong> is<br />
there<strong>for</strong>e not intrinsically a solid lubricant and<br />
requires the presence of adsorbed vapours to<br />
maintain low friction and wear.<br />
c/2<br />
c<br />
HoW TIMREX® GRApHITE And CokE<br />
poWdERS ARE pRoduCEd<br />
TIMREX® pRIMARY SYnTHETIC GRApHITE<br />
TIMREX® Primary Synthetic <strong>Graphite</strong> is produced<br />
in a unique highly controlled graphitization<br />
process which assures narrow specifications<br />
and unequalled consistent quality thanks to:<br />
monitoring of all production and processing<br />
stages, strict final inspection, and clearly defined<br />
development processes.<br />
TIMREX® Primary Synthetic <strong>Graphite</strong> shows<br />
unique properties thanks to the combination of<br />
a consistent purity, perfect crystalline structure<br />
and well defined texture.<br />
TIMREX® nATuRAL FLAkE GRApHITE<br />
TIMREX® Natural Flake <strong>Graphite</strong> is produced<br />
in a wide range of products distinguished by<br />
particle size distribution, chemistry and carbon<br />
content. <strong>Timcal</strong> mines the graphite from its own<br />
source in Lac-des-Îles, Quebec, Canada. Further<br />
processing can be done either in Lac-des-Îles or<br />
in our processing plant in Terrebonne, Quebec,<br />
Canada. All TIMREX® “Naturals” are thoroughly<br />
controlled in our laboratories to ensure quality,<br />
consistency and total customer satisfaction.<br />
TIMREX® CokE<br />
TIMREX® Petroleum Coke is calcined at appropriate<br />
temperature with low ash and sulphur<br />
content, well defined texture and consistent<br />
particle size distribution.<br />
5<br />
the product
the product<br />
EnSACo® Conductive <strong>Carbon</strong> Black<br />
<strong>for</strong> polymer compounds<br />
TYpICAL vALuES<br />
6<br />
pRopERTY TEST METHod unIT EnSACo® 150 G EnSACo® 210 G EnSACo® 250 G EnSACo® 260 G EnSACo® 350 G<br />
Form Granules (*) Granules Granules (*) Granules Granules<br />
BET nitrogen Surface Area<br />
ASTM D3037<br />
oAn<br />
Absorption<br />
ASTM D2414 (1)<br />
CoAn Crushed oAn<br />
ASTM D2414 (1)<br />
pour density<br />
ASTM D1513<br />
Moisture (as packed)<br />
ASTM D1509<br />
Sieve residue<br />
325 mesh (45 μm)<br />
ASTM D1514<br />
Ash Content<br />
ASTM D1506<br />
volatile Content<br />
TIMCAL Method 02 (2)<br />
Sulphur Content<br />
ASTM D1619<br />
Toluene Extract<br />
ASTM D4527<br />
pH<br />
ASTM D1512<br />
volume Resistivity<br />
TIMCAL Method 11 (3) (4)<br />
(1) Spring: 0.9 lbs/inch; 10 g of carbon black<br />
(2) Weight loss during heating between 105 and 950°C<br />
(3) 25% carbon black in HDPE Finathene 47100<br />
(4) 15% carbon black in HDPE Finathene 47100<br />
(*) ENSACO® 150 and ENSACO® 250 are also available in powder <strong>for</strong>m.<br />
m 2 /g 50 55 65 70 770<br />
ml/100 g 165 155 190 190 320<br />
ml/100 g 95 95 104 104 270<br />
kg/m 3 190 210 170 170 135<br />
% 0.1 0.1 0.1 0.1 1 max<br />
ppm 2 2 2 2 10<br />
% 0.1 0.1 0.01 0.01 0.03<br />
% 0.2 max 0.2 max 0.2 max 0.2 max 0.3 max<br />
% 0.5 max 0.5 max 0.02 0.02 0.02<br />
% 0.1 max 0.1 max 0.1 max 0.1 max 0.1 max<br />
8–11 8–11 8–11 8–11 8–11<br />
Ohm.cm 2000 max (3) 500 max (3) 10 max (3) 5 max (3) 20 max (4)
EnSACo® Conductive <strong>Carbon</strong> Black<br />
<strong>for</strong> polymer compounds<br />
TYpICAL EFFECTS on poLYMER CoMpoundS<br />
pRopERTY EnSACo® 150 G EnSACo® 210 G EnSACo® 250 G EnSACo® 260 G EnSACo® 350 G<br />
Form Granules (*) Granules Granules (*) Granules Granules<br />
BET nitrogen Surface Area (m 2 /g) 50 55 65 70 770<br />
oAn oil Absorption (ml/100 g) 165 155 190 190 320<br />
Conductivity ������� ������� ������� ������� �������<br />
dispersibility ������� ������� ������� ������� �������<br />
purity ������� ������� ������� ������� �������<br />
Water absorption very low very low very low very low high<br />
Surface smoothness ������� ������� ������� ������� �������<br />
Electrical/Mechanical<br />
properties balance ������� ������� ������� ������� �������<br />
Resistance to shear ������� ������� ������� ������� �������<br />
Comments to<br />
application domains<br />
excellent �������<br />
very good �������<br />
good �������<br />
quite good �������<br />
difficult �������<br />
MRG<br />
(Mechanical<br />
Rubber Goods)<br />
(*) ENSACO® 150 and ENSACO® 250 are also available in powder <strong>for</strong>m.<br />
Easy strippable<br />
insulation shields<br />
All polymers<br />
7<br />
the product
the product<br />
TIMREX® <strong>Graphite</strong> and Coke<br />
<strong>for</strong> polymer compounds<br />
TYpICAL vALuES<br />
8<br />
particle size range Grade<br />
d90 (μm)<br />
Synthetic <strong>Graphite</strong><br />
KS <strong>Graphite</strong> kS 6<br />
kS 15<br />
kS 5-25<br />
kS 44<br />
kS 5-44<br />
kS 150<br />
0 25 50 75 150<br />
SFG <strong>Graphite</strong> SFG 6<br />
SFG 44<br />
SFG 150<br />
0 25 50 75 150<br />
T <strong>Graphite</strong> T 15<br />
T 44<br />
T 75<br />
natural <strong>Graphite</strong><br />
PP Flake<br />
<strong>Graphite</strong><br />
LSG Flake<br />
<strong>Graphite</strong><br />
Large flake<br />
graphite<br />
Coke<br />
0 25 50 75 150<br />
0 25 50 75 150<br />
0 25 50 75 150<br />
cumulative size<br />
min. 80% 150 mesh (105 μm)<br />
oversize control<br />
PC Coke min. 98% 106 μm (air jet sieving)<br />
Water-based dispersion<br />
pp 10<br />
pp 44<br />
LSG 10<br />
LSG 44<br />
M150<br />
80X150<br />
Ash<br />
(%)<br />
0.06<br />
0.05<br />
0.03<br />
0.06<br />
0.02<br />
0.06<br />
0.07<br />
0.07<br />
0.03<br />
0.08<br />
0.07<br />
0.07<br />
EnSACo® Conductive <strong>Carbon</strong> Black<br />
TIMREX® <strong>Graphite</strong><br />
<strong>for</strong> polymer compounds<br />
Conductivity<br />
Targets<br />
9
TYpICAL AppLICATIonS FoR EnSACo® ConduCTIvE CARBon BLACk<br />
10<br />
Electrically<br />
conductive plastics<br />
THE SELECTIon oF A<br />
ConduCTIvE CARBon BLACk<br />
ENSACO® Conductive <strong>Carbon</strong> Blacks find their<br />
applications in an unlimited number of plastics.<br />
The combination of the polymer type and grade<br />
and the carbon black grade are determining the<br />
overall electrical and mechanical per<strong>for</strong>mance.<br />
The main parameter influencing the final conductivity<br />
of a finished part in a given polymer is<br />
the type and level of carbon black used.<br />
The higher the structure of the carbon black,<br />
the lower the level of carbon black needed to<br />
achieve the required conductivity. Nevertheless,<br />
in a minor way, other parameters like the additives<br />
in presence, the compounding or processing<br />
conditions may also influence the final<br />
conductivity of parts.<br />
Low surface area conductive carbon blacks<br />
show a particular advantage on dispersion and<br />
processing.<br />
Percolation curves – correlating the volume resistivity<br />
and the carbon black percentage – are<br />
a useful comparative tool to predict the conductivity<br />
in place and to select the more appropriate<br />
system. These curves are valid <strong>for</strong> a given<br />
<strong>for</strong>mulation and sample preparation technique.<br />
The selection of the conductive carbon black<br />
will also influence:<br />
• the compounding behaviour<br />
(dispersibility, resistance to shear, mixing<br />
cycle, melt flow index, extrusion throughput);<br />
• the surface appearance of the finished material<br />
(number of surface defects);<br />
• the mechanical properties<br />
(polymer property retention, rein<strong>for</strong>cement);<br />
• the overall price – per<strong>for</strong>mance ratio.<br />
THE pREpARATIon<br />
oF A ConduCTIvE CoMpound<br />
Suitable mixing equipments <strong>for</strong> the preparation<br />
of black conductive compounds include internal<br />
mixers, twin screw extruders, single screw<br />
kneader machines and LCM. The feeding of low<br />
bulk density, soft flake-type carbon blacks into<br />
extruders requires the use of twin screw feeders<br />
and separate introduction on an already molten<br />
polymer (split feeding technology).<br />
SoME TYpICAL FInAL<br />
pLASTICS AppLICATIonS<br />
• handling of electronic components: carrier<br />
boxes, carrier trays, carrier tapes, etc.;<br />
• films: antistatic and conductive films,<br />
packaging films, garbage bags, etc.;<br />
• automotive industry: fuel injection systems,<br />
anticorrosion systems, fuel tank inlet,<br />
electrostatically paintable parts, etc.;<br />
• transport: mobile phone parts, wheels,<br />
containers, bins, pallets, etc.;<br />
• computer: antistatic articles <strong>for</strong> computer &<br />
accessories, CD player, etc.;<br />
• health: medical applications, cleanroom<br />
equipments, articles <strong>for</strong> antistatic<br />
workplaces, etc.;<br />
• antistatic flooring;<br />
• heating element;<br />
• sensors;<br />
• pTC switches;<br />
• uv protection and pigmentation.<br />
In the following pages there are some of the results<br />
of experimental work carried out on EN-<br />
SACO® Conductive <strong>Carbon</strong> Blacks in different<br />
polymer compounds.<br />
The data shown here are given as orientation<br />
and are valid <strong>for</strong> the particular <strong>for</strong>mulations and<br />
sample preparation technique mentioned.<br />
Results in other polymers, full studies and publications<br />
are available upon request.
EnSACo® ConduCTIvE CARBon BLACkS In HdpE<br />
Infl uence of the carbon black type on the<br />
resistivity<br />
Compounding: laboratory Brabender internal mixer.<br />
Processing: compression moulding.<br />
The higher the structure of the carbon black,<br />
the lower the percolation threshold.<br />
At a concentration very near to the percolation<br />
level, when overmixed, ENSACO® 260 G off ers a<br />
higher consistency in resistivity resulting from<br />
its higher shear stability in extreme working<br />
conditions.<br />
At a concentration far above the percolation<br />
level, both blacks are very stable in resistivity<br />
when overmixed. ENSACO® 260 G shows a consistent<br />
lower resistivity.<br />
various carbon blacks in HdpE<br />
Volume Resistivity [Ohm.cm]<br />
10 9<br />
10 7<br />
10 5<br />
10 3<br />
10<br />
0.1<br />
0 10 20 30 40 50<br />
<strong>Carbon</strong> Black %<br />
Resistivity vs mixing time - 18% carbon black<br />
Volume Resistivity [Ohm.cm]<br />
Brabender Mixing Time [min]<br />
Resistivity vs mixing time - 25% carbon black<br />
Volume Resistivity [Ohm.cm]<br />
800<br />
700<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
0<br />
4 5 6 7 8 9 10<br />
7.0<br />
6.5<br />
6.0<br />
5.5<br />
5.0<br />
4.5<br />
4.0<br />
3.5<br />
3.0<br />
4 5 6 7 8 9<br />
10<br />
Brabender Mixing Time [min]<br />
ENSACO® 250 G<br />
ENSACO® 260 G<br />
ENSACO® 350 G<br />
ENSACO® 250 G<br />
ENSACO® 260 G<br />
ENSACO® 250 G<br />
ENSACO® 260 G<br />
11<br />
TYpICAL AppLICATIonS FoR EnSACo® ConduCTIvE CARBon BLACk
TYpICAL AppLICATIonS FoR EnSACo® ConduCTIvE CARBon BLACk<br />
EnSACo® ConduCTIvE CARBon BLACkS In LdpE<br />
Infl uence of the carbon black type and of the<br />
MFI of the starting polymer on the resistivity<br />
Compounding: laboratory Brabender internal mixer.<br />
Processing: compression moulding.<br />
The higher the structure of the carbon black,<br />
the lower the percolation threshold.<br />
At equal structure, the carbon black of lower<br />
surface area gets an advantage on resistivity<br />
that may be coming from the easier dispersion<br />
resulting in smoother compounding. The higher<br />
the meltfl ow index of the starting polymer, the<br />
lower the percolation threshold.<br />
EnSACo® ConduCTIvE CARBon BLACkS In pp<br />
Infl uence of the carbon black type on the<br />
resistivity. Relation between resistivity and<br />
melt fl ow index<br />
Compounding and processing: twin screw extruder Haake PTW16<br />
and realization of tapes.<br />
At same structure level, the carbon black with<br />
the lowest surface area has the smallest impact<br />
on fl uidity reduction.<br />
Infl uence of carbon black loading and<br />
processing on the resistivity<br />
Compounding: ZSK25 twin screw extruder.<br />
Processing: injection moulding.<br />
Injection moulding generates more shear than<br />
compression moulding. The closest to the percolation,<br />
the more visible is that eff ect. A concentration<br />
safety margin can overcome this<br />
phenomenon.<br />
12<br />
various carbon black in LdpE MFI 0.3 and 36 (g/10 min)<br />
Volume Resistivity [Ohm.cm]<br />
Volume Resistivity [Ohm.cm]<br />
Volume Resistivity [Ohm.cm]<br />
10 8<br />
10 6<br />
10 4<br />
10 2<br />
10<br />
0 5 10 15 20 25 30 35<br />
0<br />
10 4<br />
10 3<br />
10 2<br />
10 1<br />
10 0<br />
10 6<br />
10 5<br />
10 4<br />
10 3<br />
10 2<br />
10 1<br />
10 0<br />
<strong>Carbon</strong> Black Concentration [%]<br />
ppH MI54 (230 °C/5 kg) with various conductive carbon blacks<br />
0 10 100<br />
171<br />
MFI [230 °C/5 kg] [g/10 min]<br />
24<br />
10<br />
6<br />
4.6E + 10<br />
strands pellets + pressed pellets +<br />
plaques injection moulding<br />
54<br />
E250 G LD 0.3<br />
E250 G LD 36<br />
N472 LD 0.3<br />
N472 LD 36<br />
P-type LD 0.3<br />
P-type LD 36<br />
E250 G<br />
high structure<br />
low surface area<br />
N472<br />
high structure<br />
high surface area<br />
13.50% E250 G<br />
15% E250 G
EnSACo® ConduCTIvE CARBon BLACkS In pC<br />
Infl uence of the carbon black type<br />
on the resistivity<br />
Compounding: ZSK57 twin screw extruder.<br />
Processing: injection moulding.<br />
Infl uence of the carbon black type on<br />
mechanical and rheological per<strong>for</strong>mances<br />
Compounding: ZSK57 twin screw extruder.<br />
Processing: injection moulding.<br />
Although the concentration <strong>for</strong> percolation is<br />
double the level with ENSACO® 250 G, most<br />
mechanical properties are still better.<br />
Tensile Strength <strong>for</strong> both carbon blacks is almost<br />
at the same level.<br />
volume Resistivity (vR) in function of carbon black loading<br />
Volume Resistivity [log (Ohm.cm)]<br />
Izod [kJ/m 2 ]<br />
12<br />
11<br />
10<br />
9<br />
8<br />
7<br />
6<br />
5<br />
4<br />
3<br />
2<br />
1<br />
5 10 15<br />
20 25<br />
<strong>Carbon</strong> Black concentration [%]<br />
Izod impact strength, notched, in function of vR<br />
12<br />
11<br />
10<br />
9<br />
8<br />
7<br />
6<br />
5<br />
4<br />
1 2 3 4 5 6 7 8 9 10 11 12<br />
Volume Resistivity [log (Ohm.cm)]<br />
Tensile strength in function of vR<br />
Tensile Strength [MPa]<br />
68<br />
67<br />
66<br />
65<br />
64<br />
63<br />
62<br />
61<br />
60<br />
1 2 3 4 5 6 7 8 9 10 11 12<br />
Volume Resistivity [log (Ohm.cm)]<br />
ENSACO® 250 G<br />
ENSACO® 350 G<br />
ENSACO® 250 G<br />
ENSACO® 350 G<br />
ENSACO® 250 G<br />
ENSACO® 350 G<br />
13<br />
TYpICAL AppLICATIonS FoR EnSACo® ConduCTIvE CARBon BLACk
Typical applicaTions <strong>for</strong> Ensaco® conducTivE carbon black<br />
14<br />
Rubber<br />
<strong>Carbon</strong> black is one of the main ingredients<br />
of any rubber compound. Conductive carbon<br />
blacks are be<strong>for</strong>e all carbon blacks, to be mixed<br />
and handled as any other rein<strong>for</strong>cing or semirein<strong>for</strong>cing<br />
carbon black. They are high structure<br />
materials bulky by nature. Although the common<br />
carbon blacks are conductive by nature<br />
and impart also conductivity to the compounds<br />
when used in sufficiently high loading, conductive<br />
carbon blacks have the advantage to reach<br />
conductivities at lower loading and are often<br />
used to give the final boost to a compound already<br />
filled with other carbon blacks. As carbon<br />
black structure is the parameter determining<br />
the conductivity, structure being an additive<br />
property, the combinations of conductive and<br />
normal black can be predicted.<br />
Specifications of rubber compounds being usually<br />
quite complex and conductivity being only<br />
one of the numerous physical requirements, the<br />
use of carbon black blends is very often the<br />
only solution. In some specific cases, especially<br />
in special polymers, it occurs that the conductive<br />
carbon black is used by its own in order to<br />
maintain mechanical properties and processing<br />
at a good level.<br />
ENSACO® carbon blacks are, quite close to furnace<br />
blacks as far as the rein<strong>for</strong>cing activity is<br />
concerned. Especially the low surface area carbon<br />
blacks, grades 150, 250 and 260, are, due to<br />
their very easy dispersion, quite per<strong>for</strong>ming in<br />
most rubber compounds. ENSACO® 350 is also<br />
used in some compounds where small additions<br />
are required.<br />
A few conductive applications:<br />
• belt cover compounds;<br />
• flooring;<br />
• conveyer belts;<br />
• hoses <strong>for</strong> fuel, <strong>for</strong> conveying of powders, etc.;<br />
• cylinder coating;<br />
• shoe soles;<br />
• seals.<br />
ENSACO® 150 and 250 are also used in non conducting<br />
applications where the compounder<br />
can take profit of the low surface area and high<br />
structure of those blacks:<br />
• low hysteresis with relatively high hardness;<br />
• good thermal aging;<br />
• very good tear strength;<br />
• very good dispersion, very good mechanical<br />
per<strong>for</strong>mance at thin layer.<br />
A few non-conductive applications:<br />
• antivibration systems;<br />
• textile coating;<br />
• membranes;<br />
• articles exposed to chipping and chunking.<br />
In the following pages there are some of the results<br />
of experimental work carried out on EN-<br />
SACO® Conductive <strong>Carbon</strong> Blacks in different<br />
rubber compounds.<br />
The data shown here are given as orientation<br />
and are valid <strong>for</strong> the particular <strong>for</strong>mulations and<br />
sample preparation technique mentioned. Results<br />
in other polymers, full studies and publications<br />
are available upon request.
nBR ConduCTIvE HoSE CoMpound<br />
A B<br />
Compound<br />
EnSACo® 250<br />
Compound<br />
n-472<br />
NBR NT 3945 100 100<br />
ENSACO® 250 25<br />
N-472 25<br />
N-550 40 40<br />
ZnO 4 4<br />
Stearic acid 0.5 0.5<br />
DOP 30 30<br />
Sulphur 0.4 0.4<br />
Methyl Thuads 2 2<br />
Amax 2 2<br />
By courtesy of Bayer<br />
ConduCTIvE CR ConvEYoR BELT CovER CoMpound<br />
A B<br />
Compound<br />
EnSACo® 250<br />
Compound<br />
n-472<br />
Bayprene 610 (CR) 100 100<br />
Buna CB 10 2 2<br />
MgO Powder 4 4<br />
N-472 30<br />
ENSACO® 250 30<br />
Vulkanox DDA 1.5 1.5<br />
Vulkanox 4020 0.5 0.5<br />
Ingralen 450 15 15<br />
ZnO Powder 5 5<br />
Rhenogran ETU-80 0.2 0.2<br />
Stearic acid 0.5 0.5<br />
By courtesy of Bayer<br />
A B<br />
Compound<br />
EnSACo® 250<br />
Compound<br />
n-472<br />
t90% (min) 11.46 11.37<br />
Mooney ML (1+4) at 100° C 45.7 47.2<br />
vulcanizate data unaged at RT<br />
Shore A Hardness 70.9 72.2<br />
Stress-strain<br />
Elongation at break (%) 339 311<br />
Tensile Strength (MPa) 13.8 14.8<br />
Modulus 100% (MPa) 3.9 4.6<br />
Modulus 300% (MPa) 8.6 10.3<br />
Modulus 500% (MPa) 12.6 14.4<br />
Resistivity (Ohm.cm) 79 360<br />
Tear Strength (N/mm) 32.4 31.8<br />
A B<br />
Compound<br />
EnSACo® 250<br />
Compound<br />
n-472<br />
dispersion Rating dIk 86.8 85.8<br />
t90% (min) 20.7 21.8<br />
Mooney ML(1+4) at 100°C 62 64<br />
vulcanizate data unaged at RT<br />
Shore A hardness 62 64<br />
Stress-strain<br />
Elongation at break (%) 676 540<br />
Tensile Strength (MPa) 23.4 22.4<br />
Modulus 50% (MPa) 1.2 1.4<br />
Modulus 100% (MPa) 2.4 2.7<br />
Modulus 300% (MPa) 9.2 11.5<br />
Modulus 500% (MPa) 16.1 20.6<br />
Compression Set 24h at<br />
70°C (%)<br />
18 19<br />
Resistivity (Ohm.cm) 100 800<br />
15<br />
Typical applicaTions <strong>for</strong> Ensaco® conducTivE carbon black
TYpICAL AppLICATIonS FoR EnSACo® ConduCTIvE CARBon BLACk<br />
FkM ConduCTIvE CoMpoundS<br />
Mooney viscosity ML (1+10’), 100°C<br />
16<br />
180<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
1 2 3 4 5 6 7<br />
(*) Rejected because uncurable.<br />
Vulcanizate properties at 177°C <strong>for</strong> 10 min.<br />
Log Resistivity (ohm.cm)<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
Shore A<br />
100<br />
90<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
(*)<br />
8 9<br />
1 2 3 4 5 6 8 9<br />
1 2 3 4 5 6 8 9<br />
1 2 3 4 5 6 7 8 9<br />
vITon A-32J - Fluoroelastomer 100 100 100 100 100 100 100 100 100<br />
Mgo 3 3 3 3 3 3 3 3 3<br />
Ca(oH) 2 3 3 3 3 3 3 3 3 3<br />
MT black (n990) 20 - - - - - - 20 20<br />
EnSACo® 250G - 10 20 30 - - - 10 20<br />
n-472 SCF - - - - 10 20 30 - -<br />
vpA-2 1 1 1 1 1 1 1 1 1<br />
Total phr 127.0 117.0 127.0 137.0 117.0 127.0 137.0 137.0 147.0<br />
MT black % 15.7 0.0 0.0 0.0 0.0 0.0 0.0 14.6 13.6<br />
E250G % 0.0 8.5 15.7 21.9 0.0 0.0 0.0 7.3 13.6<br />
SCF N-472 % 0.0 0.0 0.0 0.0 8.5 15.7 21.9 0.0 0.0<br />
Experimental data provided by DuPont Dow Elastomers, Japan<br />
t 90% (min)<br />
20<br />
18<br />
16<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
70<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
1 2 3 4 5 6<br />
Compression set (%)<br />
*<br />
8 9<br />
1 2 3 4 5 6 8 9
power cables and accessories<br />
Conductive carbon black is used in semicon<br />
compounds <strong>for</strong> conductor and insulator shields.<br />
The requirements <strong>for</strong> those compounds are besides<br />
processing, a sufficient electrical conductivity,<br />
a smooth or even supersmooth surface<br />
finish, and high purity.<br />
For strippable or easy strippable compounds<br />
these requirements are added to a specific adhesion<br />
strength between the insulating layer<br />
and the insulator shield. These strippable or<br />
easy strippable layers have to peeled of by hand<br />
or using a specific peeling device.<br />
Typical polymer compositions are polyolefins or<br />
copolymers; <strong>for</strong> strippable compounds quite often<br />
blends of EVA and NBR are used.<br />
TYpICAL EvA/nBR STRIppABLE CoMpoundS<br />
Compound<br />
n-472<br />
Compound<br />
EnSACo® 210<br />
TYpICAL EEA/EBA SEMICon CoMpoundS<br />
Compound<br />
EnSACo® 250<br />
Levaprene 450 90 90 90<br />
Perbunan NT 8625 10 10 10<br />
Rhenogran P60 3 3 3<br />
N-472 40<br />
E 210 40<br />
E 250 40<br />
N-550 40 40 40<br />
Antilux 654 10 10 10<br />
Zn Stearate 1 1 1<br />
Rhenovin DDA-70 1.4 1.4 1.4<br />
Rhenofit TAC/CS 4.3 4.3 4.3<br />
Percadox BC-408 5 5 5<br />
Viscosity ML (4+1) 56 44 48<br />
Rheometer@180 t90% 3.6 3.6 3.8<br />
Mechanical properties<br />
Non aged (diff. aged)<br />
Tensile strength MPa 16.5 (-19) 16.9 (-15) 16.9 (-15)<br />
Elongation at break % 215 (-58) 180 (-50) 170 (-53)<br />
Modulus 100% MPa 11 12.2 12.7<br />
Shore A 87 (+7) 90 (+4) 89 (+7)<br />
Peel strength hot air 100°C N<br />
- after 3 days N<br />
- after 21 days N<br />
Volume resistivity (Ohm.cm) 210 6600 410<br />
7<br />
5<br />
5<br />
3<br />
4<br />
3<br />
Compound<br />
EEA<br />
EEA 100<br />
4<br />
3<br />
4<br />
Compound<br />
EBA<br />
EBA 100<br />
E 250 30 30<br />
Peroxide<br />
Mixing cond. L/d15; Feed BC; Truput 30<br />
Resistivity @ RT 7.2 5.6<br />
Resistivity @ 90°C 37 22<br />
<strong>Carbon</strong> black dispersion:
TYpICAL AppLICATIonS FoR TIMREX® GRApHITE And CokE<br />
18<br />
Self lubricating<br />
polymers<br />
The choice of a polymer-based self lubricating<br />
solid <strong>for</strong> a particular application depends mainly<br />
upon the operating conditions of: temperature,<br />
chemical environment and the maximum values<br />
of pressure (p) and sliding speed (v). For each<br />
polymer or composite material, a pv limit is quoted,<br />
which corresponds to the pressure times the<br />
sliding speed at which the material fails, either<br />
due to unacceptable de<strong>for</strong>mation, or to the high<br />
frictional energy dissipated causes surface melting,<br />
softening and excessive wear.<br />
The pv limit of a polymeric material may be increased<br />
by increasing its mechanical strength<br />
(resistance to de<strong>for</strong>mation), thermal conductivity<br />
(reduction in surface temperatures)<br />
and by decreasing friction (reduces frictional<br />
heating). In practice, thermoplastics (with the<br />
exception of PTFE) are mainly used as pure<br />
solids, since their wear resistance and frictional<br />
coefficient, are satisfactory <strong>for</strong> most applications.<br />
Solid lubricant fillers or fibre rein<strong>for</strong>cement<br />
(glass fibres, carbon fibres, textiles) are<br />
only employed under the more extreme conditions<br />
of load and speed.<br />
The major polymers employed as self lubricating<br />
solids/composites, are illustrated below.<br />
<strong>Graphite</strong> powder is widely used in polymer<br />
composites, either alone or in combination with<br />
rein<strong>for</strong>cing fibres, PTFE or various inorganic<br />
fillers, e.g. mica, talc (bottom, right table). Applications<br />
include gears, dry sliding bearings,<br />
seals, automotive and micro-mechanical parts.<br />
The properties of graphite which favour its use<br />
in polymer composites are:<br />
• low friction lamellar solid<br />
(reduces friction);<br />
• tendency to <strong>for</strong>m a transfer film on the<br />
countersurface<br />
(assists in wear reduction, particularly when<br />
graphite is applied as water based dispersion<br />
i.e. LB 1300);<br />
• high thermal conductivity<br />
(decreases temperature rise due to frictional<br />
heating);<br />
• electrical conductivity<br />
(prevent build-up of static charge which may<br />
be a problem in some cases);<br />
• chemically inert<br />
(used in conjunction with PTFE in corrosive<br />
environments);<br />
• high thermal stability<br />
(favours use in high temperature applications,<br />
e.g. polyimide graphite composites<br />
may be used up to 350°C).
Incorporation of graphite powder into a thermoplastic<br />
polymer will generally result in a<br />
reduction in the friction coeffi cient (with the exception<br />
of PTFE) but rarely improves the wear<br />
resistance. This behaviour is illustrated in the<br />
two graphs, which show the mean friction coeffi<br />
cient and specifi c wear rate <strong>for</strong> a stainless<br />
steel ball (ø = 5 mm) rubbing on discs of graphite<br />
fi lled polystyrene and polyamide at constant<br />
load (32.5 N) and speed (0.03 m/s). The specifi c<br />
wear rates of the graphite-polymer composites<br />
were calculated from the diameters of the wear<br />
tracks and the contact geometry.<br />
In the case of polystyrene, addition of 30–50%<br />
of a high purity macrocrystalline synthetic<br />
graphite (T 75), reduced both friction and wear<br />
rate. With polyamide however, addition of a<br />
graphite similar to T 75 reduced the friction<br />
coeffi cient, but caused a slight increase in the<br />
wear rate, with the fi ner particle size powder<br />
(KS 6) giving the better result. In the case of<br />
low density polyethylene and polypropylene,<br />
graphite incorporation causes both an increase<br />
in friction and wear.<br />
The results described above are thought to be<br />
related to the strength of adhesion at the polymer-graphite<br />
interface, which depends upon<br />
the wettability of the powder by the molten polymer,<br />
powder surface area to volume ratio, surface<br />
chemistry, etc. In simple terms, polystyrene<br />
shows a strong affi nity <strong>for</strong> the graphite surface,<br />
while polyolefi ns show a weak affi nity. Interfacial<br />
adhesion increases with increasing powder<br />
surface area to volume ratio, or decreasing particle<br />
size.<br />
For this reason relatively fi ne graphite powders<br />
(95%
TYpICAL AppLICATIonS FoR TIMREX® GRApHITE And CokE<br />
20<br />
Filled pTFE<br />
Polytetrafluoroethylene (PTFE) exhibits a very<br />
low coefficient of friction and retains useful mechanical<br />
properties at temperatures from -260<br />
to +260 °C <strong>for</strong> continuous use.<br />
The crystalline melting point is 327 °C, much<br />
higher than that of most other semi-crystalline<br />
polymers. Furthermore, PTFE is nearly inert<br />
chemically and does not adsorb water, leading<br />
to excellent dimensional stability. On the one<br />
hand, these characteristics of PTFE are very<br />
useful in the matrix polymer of polymer-based<br />
composites which are used in sliding applications.<br />
On the other hand, PTFE is subjected to<br />
marked cold flow under stress (de<strong>for</strong>mation<br />
and creep) and reveals the highest wear among<br />
the semicrystalline polymers.<br />
However, these disadvantages are very much<br />
improved by incorporating suitable fillers, allowing<br />
the use of PTFE in fields otherwise precluded<br />
to this polymer.<br />
The treated PTFE is generally known as filled-<br />
PTFE. There are many kinds of filled- PTFE<br />
composite because various fillers are incorporated<br />
into PTFE and one or more materials can<br />
be used simultaneously. Usually, these fillers are<br />
in <strong>for</strong>m of powders or fibers intimately mixed<br />
with the PTFE.<br />
The addition of fillers to the PTFE improves or<br />
modifies its properties depending upon the nature<br />
and quantity of filler:<br />
• remarkable increase in wear resistance;<br />
• decrease of de<strong>for</strong>mation under load and of<br />
creep;<br />
• reduction of thermal expansion;<br />
• some types of filler increase the thermal and<br />
electric conductivity.<br />
Filled PTFE is often not as strong and<br />
resilient as virgin PTFE. Sometimes, the filler<br />
limits the resistance to chemical agents and<br />
modify the electrical properties.<br />
TIMREX® GRApHITE<br />
And CokE FILLERS In FILLEd-pTFE<br />
TIMREX® pC 40-oC Coke<br />
TIMREX PC 40-OC Coke is calcined at high temperatures<br />
offering low sulphur concentration,<br />
low content of oversize particles, high apparent<br />
density and high chemical stability against most<br />
chemical substances. TIMREX® PC 40-OC Coke<br />
is added to the virgin PTFE in a percentage by<br />
weight between 10 and 35% along with small<br />
percentage of graphite.<br />
<strong>Compounds</strong> made of PTFE and TIMREX® PC<br />
40-OC Coke have excellent wear resistance<br />
and de<strong>for</strong>mation strength and compared to the<br />
virgin PTFE, they have practically unchanged<br />
chemical resistance and friction behaviour.<br />
Typical final materials that can be produced<br />
with coke filled PTFE are:<br />
engineering design components, slide bearings,<br />
valve housing and valve seats <strong>for</strong> chemical applications,<br />
piston sealing and guiding elements<br />
<strong>for</strong> dry-running compressors.<br />
TIMREX® kS44 Synthetic <strong>Graphite</strong><br />
NTIMREX® KS 44 is a Primary Synthetic <strong>Graphite</strong><br />
obtained by the full graphitisation of amorphous<br />
carbon materials through the well known<br />
Acheson process. The process parameters in the<br />
Acheson furnace such as temperatures and residential<br />
times are all optimised in order to achieve<br />
the perfect degree of crystallinity and the lowest<br />
level of impurities whereas others minor adjustments<br />
are made during the material sizing and<br />
conditioning.<br />
The percentage of TIMREX® KS 44 used in the<br />
filled PTFE vary between 5 and 15%.<br />
TIMREX® KS 44 can be used alone or in combination<br />
with glass or coke.<br />
TIMREX® KS 44 lowers the coefficient of friction<br />
and is, there<strong>for</strong>e, often added to other types of<br />
filled PTFE <strong>for</strong> improving this property (and also<br />
to improve the lifetime of the cutting tools during<br />
<strong>for</strong> instance the production of gaskets and<br />
seals). It improves the de<strong>for</strong>mation under load,<br />
strength and, to a minor degree the wear. Like<br />
coke, it serves well in corrosive environments.<br />
PTFE filled with TIMREX® KS 44 are often used in<br />
steering and shock-absorber gasket, bearings as<br />
well as in slide films <strong>for</strong> anti-static applications.
InFLuEnCE oF TIMREX®GRApHITE<br />
And CokE FILLERS In FILLEd-pTFE<br />
Wear resistance<br />
virgin PTFE shows much high wear as a result of<br />
the destruction of the banded structure due to<br />
easy slippage between the crystalline lamellae<br />
in the bands.<br />
The presence of well distributed carbon particles<br />
in the filled PTFE partially avoid the slippage<br />
between the crystalline lamellae in the<br />
bands and there<strong>for</strong>e the wear resistance is improved.<br />
de<strong>for</strong>mation strength<br />
virgin PTFE de<strong>for</strong>mation behaviour is somehow<br />
similar to the mechanism previously described.<br />
In someway the de<strong>for</strong>mation phenomena could<br />
be explained by the tendency of slippage that<br />
occurs between the crystalline lamellae. However,<br />
in this case the presence of well distributed<br />
carbon particles in the filled PTFE offers only a<br />
partial explanation to the phenomena because<br />
also hardness of these particles is important in<br />
determine an improvement of the de<strong>for</strong>mation<br />
behaviour.<br />
Friction Coefficient<br />
the coefficient of friction <strong>for</strong> various filled PTFE<br />
composites is weakly dependent upon the incorporated<br />
filler, because a thin PTFE film generally<br />
exists at the interface between the body<br />
and counter-body. Consequently the coefficient<br />
of friction is both similar in the filled PTFE and<br />
virgin PTFE. This evidence is true as long as no<br />
oversize particles are present in the filler. In fact<br />
the presence of oversize particles could lead<br />
to a radically modification of the coefficient of<br />
friction. Because of that in carbons as well as in<br />
other fillers is very important the control of oversize<br />
particles.<br />
21<br />
TYpICAL AppLICATIonS FoR TIMREX® GRApHITE And CokE
TYpICAL AppLICATIonS FoR TIMREX® GRApHITE And CokE<br />
Thermally<br />
conductive polymers<br />
WHAT IS THERMAL ConduCTIvITY?<br />
The ability of a material to conduct heat is known<br />
as its thermal conductivity. Thermal conductivity<br />
itself is nothing else than the transportation<br />
of thermal energy from high to low temperature<br />
regions. Thermal energy within a crystalline<br />
solid is conducted by electrons and/or discrete<br />
vibrational energy packets (phonons*). Each effect,<br />
phonons and movement of free electrons,<br />
contributes to the rate at which thermal energy<br />
moves. Generally, either free electrons or phonons<br />
predominate in the system.<br />
*phonons<br />
In the crystalline structures of a solid material,<br />
atoms excited into higher vibrational frequency<br />
impart vibrations into adjacent atoms<br />
via atomic bonds. This coupling creates waves<br />
which travel through the lattice structure of a<br />
material. In solid materials these lattice waves,<br />
or phonons, travel at the velocity of sound.<br />
During thermal conduction it is these waves<br />
which aid in the transport of energy.<br />
22<br />
THERMAL ConduCTIvITY<br />
oF GRApHITE<br />
<strong>Graphite</strong> is an excellent solution <strong>for</strong> making<br />
polymers thermally conductive when electrical<br />
conductivity is also tolerated. <strong>Graphite</strong><br />
operates by a phonon collision mechanism,<br />
very different from the percolation mechanism<br />
occurring with metallic powders. This mechanism,<br />
together with the particular morphology<br />
of graphite particles, helps to meet the required<br />
thermal conductivity at lower additive<br />
levels without any abrasion issues. In addition,<br />
due to its particular structure, thermal conductivity<br />
is different in the different directions<br />
of the crystal. It is highly conducting along<br />
its layers (ab direction or in-plane) and less<br />
conducting perpendicular to the layers (c direction<br />
or through-plane) because there is no<br />
bonding between the layers.<br />
In particular, expanded graphite, is well known<br />
as an excellent thermally and electrically conductive<br />
additive <strong>for</strong> polymers. On the way to<br />
graphene, high aspect ratio expanded graphite<br />
is thermally more conductive when compared<br />
to conventional carbon materials such as<br />
standard graphite and carbon fibres. However,<br />
the very low bulk density of expanded graphite<br />
makes it very difficult to feed into a polymer<br />
melt using common feeding/mixing technologies.<br />
In order to overcome the feed issues encountered<br />
by compounders with expanded<br />
graphite, TIMCAL has developed a range of<br />
products belonging to the TIMREX® C-THERM<br />
carbon-based product family.<br />
Grade Features Form Ash<br />
content (%)<br />
TIMREX®KS family Standard<br />
(spheroids)<br />
TIMREX®SFG family Standard<br />
(flakes)<br />
TIMREX®C-THERM011 High aspect ratio<br />
(pure)<br />
TIMREX®C-THERM001 High aspect ratio<br />
(pure +)<br />
Effect on<br />
thermal conductivity<br />
powder < 0.1 medium<br />
(through-plane +)<br />
powder < 0.1 medium<br />
(in-plane +)<br />
soft granules < 2.5 high<br />
soft granules < 0.3 high
THERMALLY ConduCTIvE poLYMERS<br />
Thermally conductive polymers are able to<br />
evenly distribute heat generated internally<br />
from a device and eliminate “hot spots.” Possible<br />
applications <strong>for</strong> thermally conductive<br />
plastics include heat sinks, geothermal pipes,<br />
LED light sockets, heat exchangers, appliance<br />
temperature sensors and many other industrial<br />
applications. Also thermally conductive elastomers<br />
can be found in a wide variety of industrial<br />
applications such as gaskets, vibration<br />
dampening, interface materials, and heat sinks.<br />
As highlighted in the fi gure, the low thermal<br />
conductivity of virgin PPH (~0.38 W/m.K)<br />
could be increased by one order of magnitude<br />
already at relatively low addition level<br />
(~3.5 W/m.K at 20% C-THERM). The “throughplane”<br />
thermal conductivity is about the half of<br />
the longitudinal “in-plane” thermal conductivity.<br />
These results indicate that the anisotropy<br />
of the graphite particles is conferred to the<br />
fi nal compound, due to their alignment during<br />
the injection molding process. This is an<br />
important property that has to be taken into<br />
account by design engineers. Of course the<br />
thermal conductivity strongly depends not<br />
only on the sample orientation (direction) dur-<br />
<strong>Timcal</strong> locations<br />
production plants<br />
Commercial offi ces<br />
Distributors present in<br />
many countries. For the<br />
updated list please visit<br />
www.timcal.com<br />
ing the measurement, but also on the type of<br />
polymer, the sample history (type and conditions<br />
of compounding and processing) and the<br />
measurement method.<br />
A full set of measurements to determine mechanical<br />
properties in PP were per<strong>for</strong>med and<br />
are available to customers. When tested at the<br />
same loadings, C-THERM 001/011 imparts<br />
similar mechanical properties as conventional<br />
carbon materials.<br />
Thermal Conductivity [W/m.K]<br />
4.0<br />
3.5<br />
3.0<br />
2.5<br />
2.0<br />
1.5<br />
1.0<br />
0.5<br />
0<br />
inj ><br />
In-plane<br />
Virgin PPH 20%<br />
20%<br />
ENSACO®<br />
250G<br />
Through-plane<br />
TIMREX®<br />
KS25<br />
20%<br />
TIMREX®<br />
C-THERM<br />
In-plane<br />
Through-plane<br />
23<br />
TYpICAL AppLICATIonS FoR TIMREX® GRApHITE And CokE
www.timcal.com<br />
24<br />
EuRopE<br />
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