vestakeep - professional plastics® molding compounds, as ... chopped carbon fibers are most...
TRANSCRIPT
VESTAKEEP®�PEEK—Polyether Ether Ketone Compounds
Evonik Industries is the creative industrial group from Germany focused on chemicals, energy and real estate.Evonik is a global leader in specialty chemicals. Together with the Acrylic Monomers and Acrylic PolymersBusiness Lines the High Performance Polymers Business Line is a part of the Performance Polymers Business Unit.
High Performance Polymers is specialized in manufacturing customized products and systems. We have been producing high-performance plastics for over 40 years. The extension into the field of HT polymers representsa logical expansion of our product portfolio.
Directory
Introduction .......................................................................................
Manufacture ......................................................................................
Applications .......................................................................................
Delivery .............................................................................................
Technical service ................................................................................
Overview of VESTAKEEP® compounds ................................................
Physical, thermal, tribological and mechanical properties, and fire behavior of VESTAKEEP® compounds ...................................
Processing ......................................................................................
Injection molding ............................................................................
Extrusion ........................................................................................
Physiological and toxicological evaluation of VESTAKEEP® compounds ................................................................
Information about environmental compatibility and safety .......................................................................................
Regional contacts ............................................................................
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VESTAKEEP® compounds are particularlycharacterized by the following materialproperties:
. very high heat resistance
. high rigidity
. low water absorption and therefore high dimensional stability
. high hardness
. good strength
. excellent sliding friction behavior, minimal abrasion
. good electrical characteristics
. excellent chemical resistance
. excellent hydrolytic stability
. good processability
. low tendency to form stress cracks
High-Performance Polymers has further expanded its technological lead in the high-performance polymers sectorwith VESTAKEEP® polyether ether ketone (PEEK1) compounds. VESTAKEEP® compounds are particularly suitable for applications in which extremely high mechanical, thermal, and chemical requirements must be met.
Evonik markets its VESTAKEEP® com-pounds worldwide. A proven qualitymanagement system ensures a high level of quality for the products introduced onthe market, from development throughproduction, and to quality assurance.Our system is ISO 9001:2000 andISO/TS 16949:2002 certified and iscontinually optimized. A large number of customers have tested this qualitysystem over the years and have attestedto its excellence.
For development and production, wehave also introduced an environmentmanagement system complying with ISO 14001:2005, and this is regularlycertified.
This brochure provides an overview ofthe properties and applications ofVESTAKEEP® molding compounds, aswell as processing information. VESTAKEEP® powders are covered in aseparate brochure.
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VESTAKEEP®: High Performance Polymers expanded
1PEEK is the official abbreviation for polyether etherketone according to ISO 1043. In this brochure it will be used only in this context.
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ManufactureVESTAKEEP® is polycondensed from thebuilding blocks hydrochinone and 4,4 -́difluorobenzophenone in a multistageprocess.
The base grades have a melt viscosity of100–3,000 Pas, measured at 400 °C, anda low shear of 1 sec-1, which is right forinjection molding and extrusion applica-tions. To meet the requirements of differentapplications, manufacturers can adjust theproperties of pure PEEK selectively byadding various additives:. Processing aids facilitate demolding.. Fillers and reinforcing materials increase
rigidity and dimensional stability upon exposure to heat. Chopped carbon fibers are most effective for this. Mine-rals and glass microbeads also counter- act the tendency to warp.
1 Introduction
***"Free of toxic fumes" does not apply to compounds containing PTFE. See Section 6, "Information about environmental compatibility and safety"
6
ApplicationsVESTAKEEP® compounds can be used fora wide range of applications, such as inelectrical, electronic, and communicationsengineering and in the automotive indus-try. Table 1 lists the properties that areparticularly relevant to various applica-tions.
As mentioned before, all high-perform-ance plastics from the High PerformancePolymers Business Line meet the highestquality standards.
Table 1: Performance profile of polyether ether ketones for particular applications
Hig
h te
mpe
ratu
re re
sist
ance
Che
mic
al re
sist
ance
Automotive
Aerospace andrail cars
Machinery andapparatus construction
Electrical and cable
Electronics and semiconductors
Medical technology
Food processing industry
7
s
Hyd
roly
sis r
esis
tanc
e
Phys
ical
stab
ility
Wea
r res
ista
nce
Fire
beh
avio
r
Toxi
c fu
mes
***
Elec
tric
al p
rope
rtie
s
Deg
assi
ng
Ion
extr
actio
n
Dim
ensi
onal
stab
ility
Proc
essa
bilit
y
Ster
iliza
bilit
y
Technical service - CAE supportOur technical service includes compre-hensive application engineering advicewith the aim of jointly working out tech-nically demanding system solutions withour customers. This also includes supportfrom various CAE methods in the devel-opment of molds and molded parts.
We perform processing simulations of theinjection-molding process from the fillingphase to the holding-pressure phase, in-cluding the calculation of shrinkage anddistortion, with modern software. Thisenables us to provide the following dataas early as during the product develop-ment phase . Processing process: e.g., fillability of
the mold, resulting process parameters like pressure and temperature distri-butions, cooling system, influence of various processing parameters
. Component properties: e.g., location of weld lines, air bubbles, shrinkage and distortion, fiber orientation
. Manufacturing costs: required machine size, cycle time, complexity of molded part/mold
As a rule, we require that our customersprovide us with an IGES file describingthe geometry of the article and, depend-ing on the problem definition, informa-tion regarding constraints, such as moldand process requirements. We will enterrelevant material properties such as shearviscosity, thermal conductivity and PVTbehavior into the calculation.
The results from the simulation calculationsupport further design and optimizationof the molded part and its associated in-jection mold. This frequently results in areduction of cost-intensive modificationsand in the number of iterative loops onthe mold and molded part.
Our qualified teams in Application Tech-nology and Market Development discussthe problem definition and results with thecustomer and jointly work out solutions.
Delivery of VESTAKEEP®
compoundsAs granules: in boxes with a total contentof 25 kg, divided into two polyethyleneliners each holding 12.5 kg. Twenty-fiveboxes with a total weight of 625 kg fit onone pallet. As a powder: in 10 kg boxes, each boxhaving one polyethylene liner. Twenty-five boxes with a total weight of 250 kgfit on one pallet.As a fine powder: in 15 kg boxes, eachbox having one polyethylene liner.Twenty-five boxes with a total weight of375 kg fit on one pallet.We will also deliver in bulk packagingupon request.Under normal storage conditions, storagetime is practically unlimited provided thatthe packaging has not been damaged.Avoid storing at temperatures above 45 °C.
Like other partially crystalline polyarylether ketones, unmodified VESTAKEEP®
appears amber-colored in the melt andgrayish in its solid crystalline state (natu-ral colors). VESTAKEEP® is translucent in its solid, amorphous state and has a charac-teristic amber color. We deliver most com-pounds in their natural colors. Others havea certain color inherent to them becauseof the additives they contain. They areavailable in four viscosity series, namelyVESTAKEEP® 1000, 2000, 3000 and4000, where 1000 indicates the lowestviscosity and 4000 indicates the highest.
Filling study example of a sample part
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2 Overview ofVESTAKEEP® Compounds
PowdersIn addition we offer VESTAKEEP® aspowders. They can be used in a widerange of applications, for example, in thefood, electrical, electronics, and informa-tion technology sectors and in the auto-motive industry. The powders are pro-cessed by a number of different means:press sintering, electrostatic powderspraying, flame spraying, fluidized-bedpowder sintering, sprinkling, or as a sus-pension, both in aqueous and in solvent-containing systems. Please take note of the details in ourbrochure “VESTAKEEP®—PolyetherEther Ketone Powders “. Our employeeswill be happy to provide further informa-tion and support.
2Campus® is the registered trademark of CWF GmbH/Frankfurt (Main)
Commercial productsThe PEEK compounds from High Perform-ance Polymers include a variety of differ-ent products that have been matched tothe requirements of processors and endconsumers. Table 2 provides an overviewof the characteristics of the most impor-tant products and their typical applica-tions. More detailed information aboutmost of these compounds can be found inTables 3 and 4. For further informationabout the other compounds, please con-tact the persons indicated.
Campus®
Other properties of VESTAKEEP® com-pounds and material information on theother products of the High PerformancePolymers Business Line are contained inthe plastics data base Campus®2, which isupdated regularly. You'll find Campus onthe Web at www.evonik.com/hp
Development productsDevelopment products are usually de-signed for a specific application. When weintroduce a product onto the market, thefindings and feedback we receive allowus to optimize it further. Consequently, achange in the formulation or manufactu-ring process may lead to some slightchanges in the product's properties. Weimmediately notify our customers of anychanges to the material's composition andhow these may influence the quality orspecifications of the product itself. Ifyou're looking for a product with a spe-cial requirements profile, please contactthe person indicated.
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10
4000 P
L 4000 G
4000 G black
ground
4000 FP
compounded
4000 GF30
4000 FC30
4000 CF30
3000 P
3300 G
2000 P 1000 P
1000 G2000 G
compounded
compounded
ground
2000 G black
2000 FP
2000 UFP20
2000 UFP10
2000 GF30
2000 FC30
2000 CF30
1000 CF30
5000 P
5000 G
compounded*
3000 GF30*
3000 FC30*
3000 CF30*
Overview of VESTAKEEP® grades
G = GranulesP = PowderFP = Fine powderUFP = Ultrafine powderGF30 = glass fiber-reinforced 30%FC30 = PTFE/graphite/carbon fiber (10:10:10)CF30 = carbon fiber 30%* on request
3 Properties ofVESTAKEEP® Compounds
1000 G
2000 G
2000 G black
3300 G
4000 G black
L 4000 G
5000 G
1000 CF 30
2000 CF 30
2000 GF 30
3000 CF 30*
3000 GF 30*
4000 CF 30
4000 GF 30
2000 FC 30
3000 FC 30*
4000 FC 30
Table 2: Overview of VESTAKEEP® compounds and their properties
VESTAKEEP®
low to medium-viscosity base grades for
products such as gear parts, parts used in
medical technology, and films, sheets, and
semi-finished products
specialty grade for the cable industry
high-viscosity base grades for products such
as gear parts, parts used in medical techno-
logy, and films, sheets, and semi-finished
products
low to medium-viscosity, carbon fiber or glass
fiber-reinforced compounds with increased
rigidity used for machinery, apparatuses and
aircraft and in the electrical industry
medium-viscosity, carbon fiber or glass fiber-
reinforced molding compounds with increased
or high rigidity, partially low warpage, e.g.
for housing parts
high-viscosity, carbon fiber or glass fiber-
reinforced molding compounds with increased
or high rigidity, partially low warpage, e.g.
for housing parts
special grades for applications such as bearing
arrangements and gear parts with self-lubri-
cating characteristic for use in the electrical
engineering, automotive, machinery and
apparatus construction industries
unreinforced, low-viscosity, easy-flowing
unreinforced, medium-viscosity, lubricated
unreinforced, medium-viscosity, lubricated
unreinforced, high-viscosity
unreinforced, high-viscosity, lubricated
30% carbon fibers
30% carbon fibers
30% chopped glass fibers
30% carbon fibers
30% chopped glass fibers
30% carbon fibers
30% chopped glass fibers
10% graphite
10% carbon fibers
10% PTFE
Properties Product line and applicatons Processing
IM = Injection molding, E = extrusion* on request
IM, E (film)
IM, E (film)
IM, E (film)
E
E, (IM)
E, (IM)
IM
IM
IM
(E), IM
(E), IM
(E), IM
(E), IM
IM
E, IM
E, IM
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Flow behaviorThe following illustrations serve as guidefor selecting a grade in terms of the flowa-bility of VESTAKEEP® compounds. Theyshow how injection pressure affects theflow length of unreinforced and reinforcedcompounds.
The values were obtained at a mold tem-perature of 180°C and at a processingtemperature ranging from 360 to 400°C.The results are based on a flow spiral of 6 by 2 mm.
Tribological propertiesTribology deals with friction, lubrication,and wear to bodies that come into contactwith each other. The following tableshows the initial results of a tribologicaltest with a slide in form of a pin made ofVESTAKEEP® and a rotating disk made of100Cr6 steel.
The velocity was set at 0.5 m/s, and a total distance of 2,000 m was measured.Additional tests are being conducted withlonger total distances. Please ask the indi-cated contact persons about the currentstatus of these tests.
800
700
600
500
400
300
200
100
050 100 150
Flow
leng
th [m
m]
Injection pressure [MPa]
400
350
300
250
200
150
100
50
050 100 150
Flow
leng
th [m
m]
Injection pressure [MPa]
.VESTAKEEP® 2000 FC30.VESTAKEEP® 2000 GF30.VESTAKEEP® 2000 CF30.VESTAKEEP® 4000 FC30.VESTAKEEP® 4000 GF30.VESTAKEEP® 4000 CF30
.VESTAKEEP® 1000 G.VESTAKEEP® 2000 G.VESTAKEEP® 4000 G
Unreinforced VESTAKEEP® grades
VESTAKEEP® 2000 and 4000 compounds
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Weld line strengthFor the purpose of determining weld linestrength, tensile test bars 150 x 10 x 4 mm3 in size were made on an experi-mental mold. If the runner inserts arereplaced, the mold can produce test barswith and without a weld line. The moldsurface temperature for all tensile barswas set to 180 °C.
Testing was done under standard condi-tions according to ISO 527. The resultsare summarized in the table below. It isobvious for unfilled molding compoundsthat the weld line leads to practically nodecline in the stress at yield, while for filled molding compounds tensile strengthdeclines by 50 to 70%.
Tribological properties
Coefficient of sliding friction
Wear [10-6 mm3/Nm]
23 °C, 1 N23 °C, 20 N200 °C, 1 N200 °C, 20 N
23 °C, 1 N23 °C, 20 N200 °C, 1 N200 °C, 20 N
0.40.41--
9.1410.48--
0.40.35--
9.116.68--
0.310.250.320.32
3.310.52205.76
0.330.230.260.3
6.870.2612.66.9
Temperature, load VESTAKEEP®
2000G 4000G 2000FC30 4000FC30
50 mm/min
50 mm/min
5 mm/min
5 mm/min
5 mm/min
5 mm/min
5 mm/min
5 mm/min
100
96
Tensile strength
235
236
161
152
150
146
99
95
100
111
79
82
43
41
Weld line strength
VESTAKEEP® ISO 527-1/-2 Stress at yield [MPa]without weld line with weld line
2000G
4000G
2000CF30
4000CF30
2000GF30
4000GF30
2000FC30
4000FC30
200
250
150
100
50
00.0 0.5 1.0 1.5 2.0 2.5
Stre
ss [M
Pa]
Strain [%]
.VESTAKEEP® 4000 CF30 without weld line.VESTAKEEP® 4000 CF30 with weld line.VESTAKEEP® 4000 GF30 without weld line.VESTAKEEP® 4000 GF30 with weld line.VESTAKEEP® 4000 FC30 without weld line.VESTAKEEP® 4000 FC30 with weld line
Weld line strength of various VESTAKEEP® grades
4000 FC30
4000 FC30
4000 GF30
4000 GF30
4000 CF30
4000 CF30
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Properties Standard Unit VESTAKEEP 2000 G
Physical and thermal properties and fire behavior Density 23 °C
Melting range DSC, 2nd heating
Melt volume-flow rate (MVR) 380 °C/5 kg400 °C/10 kg
ISO 1183
ISO 1133ISO 1133
ISO 75-1/2
ISO 306
ISO 11359
ISO 4589
IEC 60695IEC 60695
IEC 60695-2-12/13IEC 60695-2-12/13
ISO 294-4
ISO 62
ISO 527-1/-2
ISO 527-1/-2
ISO 527-1/-2
ISO 179/1eU
ISO 179/1eA
IEC 60112
IEC 60243-1
IEC 60250
IEC 60250
IEC 60093IEC 60093IEC 60093IEC 60093
g/cm3
°C
cm3/10 mincm3/10 min
°C°C
°C°C
10-4 K-1
%
°C
%%
%
MPa%%
MPa%
MPa
kJ/m2
kJ/m2
kJ/m2
kJ/m2
-
kV/mmkV/mm
---
---
OhmOhm*cmOhmOhm
1.30
approx. 340
70-
155205
335310
0.6
38
V-0
875960
0.71.2
0.5
100530
3700
NN
6 C6 C
200175
2521
2.82.92.8
-0.0030.005
1014
1015
1014
1015
Temperature of deflection under loadMethod A 1.8 MPaMethod B 0.45 MPa
Vicat softening temperatureMethod A 10 NMethod B 50 N
Linear thermal expansion23 °C–55 °C
longitudinal
Oxygen index 3.2 mm
Flammability acc. UL94 0.8 mm1.6 mm
Glow wire test GWIT 2 mm GWFI 2 mm
Mold shrinkagein flow direction
in transverse direction
Water absorption, saturation 23 °C
Mechanical propertiesTensile test 50 mm/minStress at yieldStrain at yieldStrain at break
Tensile test 5 mm/minTensile strengthStrain at break
Tensile modulus
CHARPY impact strength 23 °C-30 °C
CHARPY notched impact strength 23 °C-30 °C
Electrical propertiesComparative tracking index CTITest solution A 100 drops value
Electric strength K20/P50K20/K20
Relative permittivity 50 Hz1 kHz
1 MHz
Dissipation factor 50 Hz1 kHz
1 MHz
Volume resistance Volume resistivitySurface resistanceSpec. surface resistance
Table 3: Properties of VESTAKEEP® compounds
VESTAKEEP 3300 G
1.30
approx. 340
20-
155205
335305
0.6
38
V-1V-0
850960
0.71.2
0.5
98525
3600
NN
6 C6 C
200175
2521
2.82.92.8
-0.0030.005
1014
1015
1014
1015
N = no breakC = complete break,
incl. hinge break H
15
VESTAKEEP 4000 G
1.30
approx. 340
11-
155205
335305
0.6
38
V-1V-0
850960
1.11.8
0.5
96530
3500
NN
7 C6 C
200175
2521
2.82.92.8
-0.0030.005
1014
1015
1014
1015
VESTAKEEP 2000 GF30
1.50
approx. 340
17-
323338
340335
0.3
45
V-1V-0
875960
0.40.9
0.4
1652
11000
55 C65 C
9 C8 C
200175
2523
3.43.33.3
-0.0020.004
1014
1015
1014
1015
VESTAKEEP 4000 GF30
1.50
approx. 340
2-
312335
340335
0.3
45
V-1V-0
875960
0.40.7
0.4
1652
11000
70 C75 C
10 C9 C
200175
2523
3.43.33.3
0.0020.004
1014
1015
1014
1015
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Properties Standard Unit VESTAKEEP 2000 CF30
Physical and thermal properties and fire behavior Density 23 °C
Melting range DSC, 2nd heating
Melt volume-flow rate (MVR) 380 °C/5 kg400 °C/10 kg
ISO 1183
ISO 1133ISO 1133
ISO 75-1/2
ISO 306
ISO 11359
ISO 4589
IEC 60695IEC 60695
IEC 60695-2-12/13IEC 60695-2-12/13
ISO 294-4
ISO 62
ISO 527-1/-2
ISO 527-1/-2
ISO 527-1/-2
ISO 179/1eU
ISO 179/1eA
IEC 60112
IEC 60243-1
IEC 60250
IEC 60250
IEC 60093IEC 60093IEC 60093IEC 60093
g/cm3
°C
cm3/10 mincm3/10 min
°C°C
°C°C
10-4 K-1
%
°C
%%
%
MPa%%
MPa%
MPa
kJ/m2
kJ/m2
kJ/m2
kJ/m2
-
kV/mmkV/mm
---
---
OhmOhm*cmOhmOhm
1.38
approx. 340
10-
330340
343340
0.1
47
V-0V-0
875960
0.10.7
0.4
2402
23000
45 C45 C
9 C8 C
--
--
--17
--0.23
105
106
105
106
Temperature of deflection under loadMethod A 1.8 MPaMethod B 0.45 MPa
Vicat softening temperatureMethod A 10 NMethod B 50 N
Linear thermal expansion23 °C–55 °C
longitudinal
Oxygen index 3.2 mm
Flammability acc. UL94 0.8 mm1.6 mm
Glow wire test GWIT 2 mm GWFI 2 mm
Mold shrinkagein flow direction
in transverse direction
Water absorption, saturation 23 °C
Mechanical propertiesTensile test 50 mm/minStress at yieldStrain at yieldStrain at break
Tensile test 5 mm/minTensile strengthStrain at break
Tensile modulus
CHARPY impact strength 23 °C-30 °C
CHARPY notched impact strength 23 °C-30 °C
Electrical propertiesComparative tracking index CTITest solution A 100 drops value
Electric strength K20/P50K20/K20
Relative permittivity 50 Hz1 kHz
1 MHz
Dissipation factor 50 Hz1 kHz
1 MHz
Volume resistance Volume resistivitySurface resistanceSpec. surface resistance
Table 4: Properties of VESTAKEEP® compounds
N = no breakC = complete break,
incl. hinge break H
17
VESTAKEEP 4000 CF30
1.40
approx. 340
-3
325335
343340
0.1
47
V-0V-0
850960
0.10.6
0.4
2402
23000
60 C60 C
10 C9 C
--
--
--17
--0.23
105
106
105
106
VESTAKEEP 2000 FC30
1.45
approx. 340
15-
320337
340335
0.2
44
V-0V-0
900960
0.40.6
0.4
1452
11500
40 C40 C
6 C5 C
--
--
6.15.54.9
0.070.040.02
105
107
105
106
VESTAKEEP 4000 FC30
1.45
approx. 340
2.5-
310330
340335
0.2
44
V-0V-0
900960
0.30.5
0.4
1402
11500
45 C45 C
8 C7 C
--
--
6.15.54.9
0.070.040.02
105
107
105
106
18
Drying
VESTAKEEP® leaves the factory with amoisture content of less than 0.25 wt.%.We nevertheless recommend additionaldrying in order to obtain qualitativelyhigh-grade extrudates.. Drying temperature: 150–160 °C. Drying time: 2–3 hours in the dry-air
dryer or vacuum furnace. A drying cabi-net is good for base powders. We also recommend 4 or more hours for film applications
. Hopper: heated or thermally insulated
. Max. residual moisture: < 0.02weight-% is recommended for base powders and granules
Suggestions:. The saturation temperature of the dryer
should be at least -30 °C . Convey the granules with dried air ex-
clusively . Use PU hoses for conveying, not PVC
hoses
Injection molding
Plasticating Unit
Screw and barrelStandard screw (three-zone screw) with alength between 18 and 24 D are usuallysuitable. Zone breakdown: feed 55–60%, com-
pression 20–25%, metering 20–25% . Flight depth ratio 2.0–2.5:1 The plasticating unit should be designedso that the required metered volumes liebetween 30% and 70% of the maximumpossible shot volume. This will produce ahomogenous melt quality.
Back flow valveCommercially available three-piece backflow valves are used. Machine manufac-turers provide a wide choice of differentdesigns. Rapid, reproducible closing of thevalve during injection is an indispensablerequirement for ensuring that quality andweight of the molded part remain constant.
NozzleIn general, free-flow nozzles are recom-mended. A slight easing of the decompres-sion of about 3 to 5 mm will counteract thedischarge of the melt from the nozzle bore.But decompression distances that are toolong will cause air to become trapped,resulting in burned spots and gate marks. Shut-off nozzles are less suitable becauseloss of injection pressure must be expectedbecause of the poorer melt transport. It isalso possible for thermal damage to occurin the existing "dead corners” because ofretention times being too long.In all of the nozzle types used, it is necessaryto make sure that the heat output is suffi-cient. To prevent "freeze-off” of the nozzleand formation of a "cold slug” when thesprue bush is adjacent to the injection unit,the band heater should cover the entirelength of the die body.In order to demold a sprue gate withouttrouble, the outlet diameter of the machinenozzle should be approximately 0.5 to 1 mm smaller than the bore diameter ofthe sprue bush.
General Information
For injection molding and extrusionprocessing, VESTAKEEP® polymers andcompounds are primarily processed ingranular form. Most standard screwmachines are suitable for this.The plas-ticating unit should be designed forprocess temperatures of up to 450 °C.It may also be necessary to modify thecontroller, band heaters, and tempera-ture sensors. In addition, we recom-mend that the instructions listed belowbe observed when processing PEEK.
4 Processing
It is also important that the radius of themachine nozzle is smaller than that of thesprue bush (e.g. nozzle radius = 35 mm,sprue-bush radius = 40 mm).
Injection unitScrews made of corrosion-protected andwear-protected high-alloy PM steels areusually used to process VESTAKEEP® with-in the injection cylinder. We recommend abimetallic design for the injection cylin-der.Since VESTAKEEP® has a strong tendencyto adhere to metallic surfaces, it is possiblefor cracks to form in the nitrided layer ofnitrided screw surfaces during cooling.The adhesion can be so strong that thenitride layer can peel off from the steelcore. Metallic areas that come into direct con-tact with the melt should be highly pol-ished to prevent deposits that could causethermal decomposition due to the in-creased retention time. In order to obtaingood conveying action by the screw, thefriction between the granules and the cyl-inder wall must be greater than that be-tween the granules and the screw surface.
Cleaning
GeneralRemove other polymers completely fromthe plasticating unit before processingVESTAKEEP® compounds. This can beaccomplished either by cleaning the cylin-der and screw mechanically or by usingsuitable cleaning materials. These arematerials that are thermally stable up toapproximately 380 °C. One suitable ma-terial is a high-viscosity PC containingglass fibers (e.g., MAKROLON® 8345,ASACLEAN®). Other suitable materialsinclude PES, PEI and, with limitations,high-viscosity PP. Since PP decomposesat these temperatures, effective venti-lation is important.
Material change over to VESTAKEEP®
1. Set the temperature to the temperaturenormally used when processing the material to be removed.
2. Introduce the cleaning material and continue rinsing until no traces of the material to be removed can be detected.
3. Run the screw dry.4. Set the cylinder temperatures to the
values required for PEEK processing.5. When the temperatures have been
attained, feed the material through the cylinder long enough that a clean melt is present.
Cleaning while shutting down theinjection molding machineCompletely remove the PEEK melt fromthe cylinder before processing another material. There exists the danger that themelt could solidify with the nitride layerof the cylinder and screw while cooling.Because of the high adhesive forces, thislayer could peel and damage the screw(see “Tool steel”). This means that thecylinder may be allowed to cool only aftercleaning and careful rinsing.
Cleaning process:1. Remove material form the injection
molding machine (hopper).2. Introduce the cleaning material and
continue rinsing until there are no longer any visible traces of the PEEK material.
3. Reduce cylinder temperatures to a lower temperature (350 °C) that is still acceptable for PEEK.
4. Continue rinsing with the cleaning material until the actual cylinder tem-perature drops below 300 °C. An evenlower temperature (< 250 °C) may be required, depending on cleaning ma- terial.
5. Possibility of mechanical cleaning
19
Clamping unit
Mold clamping forceThe required clamping force depends onthe size of the expected molding area(sprue area plus article area) and theresulting internal pressure of the mold.An adequate clamping force must beensured since the injection pressures of100 to 200 MPa are very high in com-parison with other projects.The production of precision parts andinjection molded articles that have large flow-distance/wall-thickness ratios in-volve pressures in excess of 200 MPa.
Tool
Tool steelFor the cavity, use steel grades that still have a hardness of about 52 to 54 HRC at the high processing temperatures, forexample. 1.2343 ESU (X38CrMoV51) - easy to
polish. 1.2379 (X155CrVMo121) - core har-
dened. 1.2083 (X42Cr13 ) - core hardened,
corrosion-resistant. 1.2316 (X38CrMo16) – non-rusting
steel, easy to polish
Wall thickness of molded partsMinimum wall thickness:. approx. 1 mm for unfilled PEEK mold-
ing compounds. approx. 1.5 mm for filled PEEK molding
compounds
Flow-distance/wall-thickness ratioMaximum attainable flow distance/wallthickness ratios for unfilled materials and2 mm wall thickness up to 200 : 1 (con-ditions: melt temperature 380 °C, moldtemperature 180 °C, injection pressure140 MPa)
Sprue. Minimum diameter: 4 mm, for direct
gating 1 to 1.5 times the thickness ofthe molded article
. Demolding draft angle: at least 2°
. Ejector claw: special for direct gating
. Manifold: round or trapezoidal (cross section as large as possible for small surface)
GateDependent on melt volume, number ofcavities, component geometry; nearly all common systems are suitable; butsmall tunnel gates freeze off quickly and are preferably used when short holding-pressure times are required; however; thin flow areas should be avoided.Minimum gate diameter: . approx. 1.0 mm for unfilled materials. approx. 2.0 mm for reinforced materials
Hot runner systemWe recommend exclusively nozzles thathave good external heating with a heat-conducting torpedo in the nozzle tip forprocessing VESTAKEEP® with hot runnersystems. These systems generally featurelow pressure losses and clearly definedflow-channel cross sections that enhanceflow. For reinforced VESTAKEEP® grades, heat-conducting torpedoes made of hard metaloffer adequate protection against wear.Needle shut-off systems can also be usedin practice. However, we do not recom-mend them for compounds that containfillers (e.g. GF, CF).Frequently non-corrosive types of steelwith increased chrome content (1.2316, see Mold) are used to process PEEK in hotrunner systems. They must permanentlymaintain process temperatures up to 450 °C.To achieve an exact thermal separationbetween nozzle and mold, it is necessary to correctly follow the manufacturer’sinstructions when implementing the gategeometry. This is important in order toavoid surface defects and unclean sepa-ration points.
20
The feed-point diameter for reinforcedcompounds should be around 0.2 to 0.3 mm larger than in the case of unrein-forced grades.The hot runner controllers should be ableto correct temperature deviations of up to+/- 1 °C. To keep pressure losses as small as pos-sible, the gate openings should be dimen-sioned as large as possible. Many manufacturers can calculate pres-sure losses in the hot runner based on material data.
VentingVenting slots in mold parting surface or,in particular, at the end of the runners cangenerally be incorporated 0.02 mm deepwithout burr formation. If necessary, thedepth may be increased to 0.05 mm but itis then necessary to watch out for burrformation.Further support of venting by means ofappropriately fashioned ejector pins is possible. Vent packages at critical pointsof confluence can also help prevent"burnings.” Compressed air in the cavitycan reach temperatures as high as 1000 °Cand result in damage to the molded part.It is important to provide adequate venti-lation in blind holes in particular, becausemolded articles may otherwise not fillcompletely. Vent pins that can be easilyremoved for cleaning are helpful.
Pressure gaugeWe recommend the use of an internalpressure gauge to set the switching point precisely.
Temperature controlSince mold surface temperatures can beas high as 220 °C, we recommend the useof oil-operated tempering devices. Thedevices should be designed for operatingtemperatures of up to 250 °C. Specialhoses that are approved for high operatingtemperatures should be used. For themold feed system, tight threaded jointsare preferable to plug and couplingsystems. It is also necessary to pay attention to themaximum permissible operating tem-peratures of all seals (Viton®, Kalrez®)within the mold as well as the seals in the hydraulic cylinders of core pullers. Electrically heated injection molds, inwhich there is a much slower reaction to temperature changes because no heat isdissipated, can also be used.The external surfaces of the mold can becovered with insulating plates to mini-mize loss of heat to the surroundings fromthermal radiation. We recommend theuse of heat-insulating plates between themachine support plates and mold.
21
Processing conditions
Cylinder and mold temperaturesWe recommend the following melt temperatures to process VESTAKEEP® successfully:
Set the cylinder temperature profile slightly rising with the feed temperature 10 to 20 °C lower than the last cylinder heat zone temperature. The optimum melt temperature depends on various factors, such as the retention time inthe plasticizing cylinder and the wall thickness of the molded article. The melt temper-atures recommended in the above table can be used as starting temperatures. They canbe increased by 10 to 20 °C for short residence times and thin wall thicknesses.
Select high temperatures to achieve a high degree of crystallization.
Screw speedPeripheral screw speed Rotational speed, e.g., #30 screwUnfilled materials: 5–10 m/min 50–100 rpmReinforced materials: max. 6 m/min 60 rpmHigher speeds are not recommended because of the possibility of thermal overload of the melt caused by frictional heating from large local shear effects.
22
Back pressureBack pressures between 2 and 8 MPaimprove the melt homogeneity. For rein-forced VESTAKEEP® grades, we recom-mend a lower back pressure in order toprocess the fillers as gently as possible andobtain the mechanical properties.
DecompressionWe recommend a decompression distanceof approx. 3 to 5 mm for melt ejectionfrom the nozzle.
Injection speedThe injection speed should be as high aspossible and therefore requires injectionpressures up to 250 MPa, depending onthe prevailing mold conditions (gate dimensioning, flashing, ventilation, etc.).For short filling times, we recommend storage machines.
*VESTAKEEP® compounds, which are filled with PTFE (FC grades), can release highly toxic and caustic gases at temperatures exceeding 380 °C.If conditions leading to this decomposition are not avoidable, direct exposure of the employees must be prevented, e.g. by an efficient with- drawal of exhaust air.
Melt temperatures
VESTAKEEP®
1000 G
[°C]360
[°C]370
[°C]375
[°C]380
[°C]390
[°C]390*
[°C]400
2000 G 3000 G 4000 G 4000 GF30 4000 FC30 4000 CF30
Typical values for cylinder and mold temperatures
VESTAKEEP® GVESTAKEEP® CF
Nozzle[°C]
370–380400–410
Zone 3[°C]
360–380390–410
Zone 2[°C]
360–370390–400
Zone 1[°C]
350–360380-390
Hopper[°C]
70–10070–100
Moldtemp. [°C]
160-200180-220
Extrusion
Plasticating unit
ExtruderAs mentioned above, most standard screwmachines are suitable for PEEK process-ing provided that they can operate reliablyat the required processing temperatures.Standard screws (three-zone screw) witha length between 18 and 24 D are nor-mally suitable: Zone breakdown: feed 12 D, compression 4–6 D, metering 4–6 DFlight depth ratio: 2–3:1For screws and barrels, we recommendsufficiently corrosion- and abrasion-resistant steels and bimetals.
23
Injection pressureThe injection molding machine should bedesigned for injection pressures up to250 MPa, the required injection pressureessentially depending on the melt and mold temperature and the flow-distance/wall thickness ratio of the component.
Holding pressureAs a rule, holding pressures of up to 120MPa in combination with an optimized holding-pressure time should be sufficientto produce components without sinkmarks. A melt cushion of 3 to 5 mm willensure adequate pressure transmission from the injection cylinder to the cavity.The gating must be dimension largeenough to allow the holding pressure toact upon the molded part for a sufficient length of time.
Holding pressure timeSince VESTAKEEP® materials have a highsolidification point (TK approx. 345 °C), gates to the molded article can freeze offprematurely. The optimum holding pressure time must be established by deter-mining the gate seal-off point. Holdingpressure times that are too short can resultin sink marks and voids because of aninsufficient supply of material comingfrom the plasticizing cylinder.
Production stopsFor relatively short production stops (up
to 1 hour), the material can be kept at 360 °C without any significant decom-position. For downtimes longer than 1–3 hours, the temperature should be dropped to 340 °C. The material possesses adequatemelt stability at this temperature.When restarting, rinse the cylinder ade-quately and reject the first molded parts.For interruptions lasting more than 3hours, a cleaning is recommended. See “Cleaning.”
If conventionally nitrided parts are used,make sure that the VESTAKEEP® melt doesnot cool on the surface and solidify on thenitride layer. The adhesion can be sostrong that cracks will form and the nitridelayer can peel off from the steel core.
For measures to eliminate defects in injection molded parts see Table 5 on page 26.
Processing temperaturesThe optimum processing temperatures of PEEK depend on various factors, such as theviscosity of the compound and the technical parameters of the extrusion unit. The material can be heated in the hopper to improve the melting characteristics of thegranules. The recommended temperatures lie in the range 140 °C–180 °C. If it is notpossible to heat the hopper, the granules can be fed warm. The temperatures of thefeed zone must be chosen on the basis of the viscosity and filler of the material. Thefirst heating zone should be heated to about 350 °C–360 °C. Conventional extrusionexhibits a temperature profile similar to the following:
24
Mold We recommend that you optimize theheating to achieve a uniformly high tem-perature distribution (e.g. die heating forflat sheet dies). In order to reach and maintain these temperatures, it is impor-tant that thermal radiation be kept low. If this is not possible, the mold should beinsulated with appropriate thermal insu-lation.Metallic areas that come into direct con-tact with the melt should be highly po-lished to reduce the adhesion of the meltto the metal, thus reducing the residencetime and less disturbing the flow of themelt.
Downstream unit It is possible to obtain different propertiesfor the extrudate by tempering the down-stream unit (chill roll, calendar and cali-bration temperatures). VESTAKEEP® is asemi-crystalline material whose properties(transparency, color, mechanics, etc.) arestrongly dependant on the cooling charac-teristics. If a semi-crystalline structure is tobe achieved, it is necessary to temper theextrudate in the downstream unit, possiblyup to 200 °C and higher.
Material change-overFor a material change-over from other poly-
mers to PEEK, it is necessary to rinse tempe-
rature-unstable materials completely out of
the cylinder and downstream units. Decom-
position reactions and gas formation could
otherwise occur. In most cases, we recom-
mend mechanical cleaning, however. See
the corresponding procedure in the Section
"Mechanical cleaning”.
Material change-over to VESTAKEEP®
1. Extrude the cleaning material in accord-ance with the processing recommenda-tions of the material manufacturer. Rinse until there is no longer any trace of the material to be removed.
2. Run the screw dry.3. Set to the temperatures required for
PEEK processing.4. When the temperatures have been
attained, fill VESTAKEEP® into the material hopper and extrude until a clean melt is present.
Typical processing temperatures for VESTAKEEP®
VESTAKEEP® G
Nozzle[°C]
370–380
Zone 3[°C]
360–380
Zone 2[°C]
360–370
Zone 1[°C]
350–360
Hopper[°C]
140–180
25
Material change-over of VESTAKEEP® to other polymersBefore another material can be processed,it is necessary to completely remove thePEEK melt from the cylinder. The com-pound to be processed next should be insensitive to heat in order to avoid de-composition reactions and gas formation.
CleaningRemove other polymers completely fromthe plasticating unit before processingVESTAKEEP® compounds. This can beaccomplished either by cleaning the cylin-der and screw mechanically or by usingsuitable cleaning materials. These arematerials that are thermally stable up toapproximately 380 °C. One suitable ma-terial is a high-viscosity PC containingglass fibers (e.g., MAKROLON® 8345,ASACLEAN®). Other suitable materialsinclude PES, PEI and, with limitations,high-viscosity PP. Since PP decomposes atthese temperatures, effective ventilation isimportant.
Cleaning process1. Remove the material from the hopper.2. Run the screw dry.3. Feed in the cleaning material and con-
tinue extruding until there is no longer any visible trace of the PEEK material. Please observe the corresponding pro-cessing recommendations of the mate-rial manufacturer.
4. Reduce the cylinder temperatures to alower value that is still acceptable for PEEK (350 °C) and, if necessary, reducefurther to the temperatures of the cleaning agent.
5. Continue to rinse with the cleaning material until the typical temperaturesof the cleaning material have been attained.
6. If necessary rinse with another material that can be easily removed from the metal before mechanical cleaning.
7. Mechanical cleaning
Other processing instructionsFor longer downtimes, the temperatureshould be dropped to 340 °C. The mate-rial possesses adequate melt stability atthis temperature. For downtimes exceed-ing 3 hours cleaning is recommended. See "Cleaning.”If the VESTAKEEP® melt cools down with-in the cylinder, the compound will harden(similarly as in the case of PC). Because ofthe high adhesive forces that arise, it ispossible, especially in the case of conven-tionally nitrided surfaces, that cracks willarise or even that the nitride layer will peeloff, raising the possibility of damage to thescrew (see "Tool steel").
26
= increase= decrease . = do
P = profile
q
p
Table 5: Measures to eliminate defects in PEEK injection molded parts
Mol
dte
mpe
ratu
re
Mel
ttem
pera
ture
Noz
zle
tem
pera
ture
Noz
zle
cont
actt
ime
Rot
atio
nals
peed
ofsc
rew
Brittleness
Incompletelyfilled
Transparent edges/dark regions
Cold plugs
Sink marks/voids
Burn marks
Flashing
Streaking
Dull surfaces(Reinforced grades)
Overheating
Stresses
Flow line
Too little injected
Insufficient flux
Mold design
Mold temperature too low
Melt transitions within the nozzle
Inadequate time and pressure conditions
Mold design
Air trapped in cavity
Clamping force too small/fittingaccuracy of the mold halves
Overheated molding compound
Humid material
Insufficient injection speed
Shear on the melt too strong
q
p
p
p
q
q
q
p
p
p
p
p
q
p
Defect in the molding Possible cause
q
q
q
q
q
p
27
Inje
ctio
nsp
eed
Shot
volu
me
Inje
ctio
npr
essu
re
Hol
ding
pres
sure
Cyc
letim
e
Gat
ecr
osss
ectio
n
Mov
eth
ega
tepo
sitio
n
Impr
ove
vent
ing
ofca
vity
Cla
mpi
ngfo
rce
Dry
the
mat
eria
l
p
p
q
q
q
p
q
q P
q
p
p
p
p p .. .
. . .
.
. .
p
q
p
p
28
5 Physiological and Toxicological Evaluationof VESTAKEEP® Compounds
Food Contact – EU-StatusUniform regulations for plastics that comeinto contact with foodstuffs exist at theEuropean level. The consolidated EU Di-rective 2002/72/EC and its amendmentsapply. It lists approved monomers and,since December 31, 2006, approved plastic additives as positive. In other words,in Europe only approved monomers andadditives on the EU positive lists may comeinto contact with food. Nationally ap-proved additives are no longer permitted.However, nationally approved additivesthat had been submitted to the EU Com-mission for approval prior to 12/31/06constitute an exception. These additivesmay continue to be used for food contactbeyond 12/31/06 during a transitionperiod until final evaluation and approvalby the EU Commission.
Unreinforced and glass fiber-reinforcedVESTAKEEP® compounds are approved for direct food contact in the EuropeanUnion because the monomers and addi-tives on which they are based satisfy theabove Guideline and its updates.Restrictive migration values must be ob-served on the finished article and, forglass fiber-reinforced VESTAKEEP®
grades, special marketing conditions andconditions of use must also be observed(principle of "Mutual Recognition”).
The Environment, Health, Safety & Qual-ity Department, which is responsible forthe High Performance Polymers BusinessUnit, provides general information on thetoxicological properties of VESTAKEEP®
compounds and relevant analysis pertain-ing to their contact with foodstuffs. Thedepartment is also responsible for provid-ing information about product safety andproducing the EC Safety Data Sheets forVESTAKEEP®. Please direct all questionson the subject to the indicated contactpersons.
VESTAKEEP® compounds are water-insol-uble, solid polymers that are largely inertphysiologically. No toxicity is expectedfrom single contact or even multiple con-tacts, because VESTAKEEP® products arenot absorbed either through the skin orthrough the gastrointestinal tract. As inthe case of other inert dusts, exposure toVESTAKEEP® dusts could possibly result inmechanical irritation in the upper respira-tory passages and the mucous membranesof the eye. Irritation or sensitization of theskin is not expected. Based on our bestcurrent understanding, VESTAKEEP®
does not have any adverse effects on man,animals, plants, or microorganisms.Please direct any further questions re-garding product safety to the indicatedcontact persons.
Food contact – FDA statusIn the United States, the FDA Regulation 21 CFR 177.2415 covers plastics thatcome into contact with food. Since thepolymers on which the unreinforced andglass fiber-reinforced VESTAKEEP® com-pounds are based meet these regulations,these compounds are suitable for food-contact applications in the United Statespursuant to Section 177.1415 for articlesintended for repeated use.
For further information, please contactthe indicated contact persons.
29
Medical applicationsFor medical applications, the Europeanapproval procedure is laid down in Di-rective 93/42/EEC. The national imple-mentation of this directive into Germanlaw is the Medizinproduktegesetz (Medi-cal Products Act) of August 1994. Thedetailed procedure to be followed is described in the pertinent internationaland national standards (e.g., ISO 10993,DIN EN 30993-1). The DAB monographs(German Pharmacopoeia, current edition)or those of the European Pharmacopoeia(current edition 2008) can be used assupplementary regulatory works to makethe decision in special cases.
In cases of doubt, the moldings or semi-finished products must be investigated bythe manufacturer or user, taking the rele-vant conditions of use into consideration.Our staff can provide you with informa-tion about their experiences with variousapproval processes.
6 Information about Environmental Compatibility and Safety
VESTAKEEP® compounds are noncombus-tible. Flammable gases can be released atmelt temperatures above 450 °C. Sincethe spectrum of crack and combustionproducts greatly depends on the combus-tion conditions, it is not possible to makeany general statements here.
VESTAKEEP® compounds, which are filledwith PTFE (FC grades), can release highlytoxic and caustic gases at temperaturesexceeding 380 °C. If conditions leadingto this decomposition are not avoidable,direct exposure of the employees must beprevented, e.g. by an efficient withdrawalof exhaust air. In addition to our instruc-tions, please also comply with the safetydata sheet for the compound in question.
VESTAKEEP® compounds can be easilyrecycled.The properties of the recyclatesare only slightly affected. For questionsregarding the recycling of VESTAKEEP®
compounds, please contact the indicatedcontact persons.
VESTAKEEP® compounds are non-hazar-dous substances that are not governed byany particular safety regulations. Theycan be disposed of in accordance withlocal ordinances. Further information canbe found in the EC safety data sheet forVESTAKEEP®. Recycling is, however, pre-ferred and advisable for economic reasons.
No dangerous byproducts are formed ifVESTAKEEP® is processed properly. Careshould be taken, however, to ventilate theworking area properly. Detailed direc-tions about handling VESTAKEEP® pro-ducts can be found in the “Processing”section of this brochure.
Degradation of the material during pro-cessing is shown by a discoloration of themelt. Degraded material should be quicklyremoved from the machine and cooledunder water in order to minimize anytroublesome smells or fumes.
No pigments or additives containing cad-mium are used.
30
Integrated expertise: no region without direct contacts
Northern Germany, BeneluxKarsten Goldstein phone +49 2365204790mobile +49 [email protected]
Southern Germany, IberiaLudger Malmedyphone +49 8251870157mobile +49 [email protected]
Central GermanyAchim Hiltropphone +49 2017988871mobile +49 [email protected]
Austria, SwitzerlandBeat Bertschingerphone +41 19380665mobile +41 [email protected]
Czech. Republic, SlovakiaMiroslav Sarmanphone +420 272111817mobile +420 [email protected]
FranceGéraud Apchin phone +33 139757985mobile +33 [email protected]
ItalyRoberto Sacchi phone +39 0371219363mobile +39 [email protected]
NordicGöran Winnerstamphone +46 40459500mobile +46 [email protected]
PolandAndrzej Wolak phone +48 223181007mobile +48 [email protected]
TurkeyMehmet Ali Ersudas phone +90 2163959961255mobile +90 [email protected]
UK, EireHameem Yasinphone +44 1214432016mobile +44 [email protected]
AmericasFernando Jorgephone +1 9735418397mobile +1 [email protected]
BrazilGermano Coelho phone +55 113146 4150mobile +55 [email protected]
AustraliaPeter Gibsonphone +61 298914011mobile +61 [email protected]
ChinaShelley Deng phone +86 2161191368mobile +86 [email protected]
IndiaAshok Bandella phone +91 2256307070mobile +91 [email protected]
JapanKatsumi Sawadaphone +81 353246332mobile +81 [email protected]
KoreaHongil Kimphone +82 325102442mobile +82 [email protected]
. direct contactsp further contacts
. .
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p
p
p
p
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p
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31
Evonik Degussa GmbH High Performance Polymers45764 MarlGermany
phone +49 2365 49-9878fax +49 2365 49-5992www.evonik.com/hpwww.vestakeep.com
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This information and all further technical advice arebased on Evonik Degussa’s present knowledge andexperience. However, Evonik Degussa assumes noliability for providing such information and adviceincluding the extent to which such information andadvice may relate to existing third party intellectualproperty rights, especially patent rights. In partic-ular, Evonik Degussa disclaims all conditions andwarranties, whether expressed or implied, includingthe implied warranties of fitness for a particular pur-pose or merchantability. Evonik Degussa shall not beresponsible for consequential, indirect or incidentaldamages (including loss of profits) of any kind.Evonik Degussa reserves the right to make anychanges according to technological progress or fur-ther developments. It is the customer’s responsibilityand obligation to carefully inspect and test any in-coming goods. Performance of the product(s) de-scribed herein should be verified by testing and carried out only by qualified experts. It is the soleresponsibility of the customer to carry out and ar-range for any such testing. Reference to trade namesused by other companies is neither a recommenda-tion, nor an endorsement of any product and does not imply that similar products could not be used.
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