1. The Next Generation of
Polyphthalamide
High-performance Polyamides.
For years and to an increasing ex-
tent, plastics have been replacing
diecast metal parts. Structural
and functional parts for many
applications can now be pro-
duced from polyphthalamide
(PPA). These can be found under
the hood in automobiles, in hot
water applications in the sanitary
field as well as in industrial ap-
plications, e.g. for coffee ma-
chines. An advanced grade of this
high-performance polyamide is
characterized by its extremely low
moisture uptake.
A polyphthalamide with extremely low moisture uptake is particularly well-suited for
production of connectors in the electronics sector
75
COMPOUNDS ■
V
Kunststoffe international 8/2008
MICHAEL KAISSER
T
he polyphthalamide Grivory HT is
characterized by high rigidity and
strength at temperatures up to
150°C. It is very resistant to chemicals
and exhibits minimal change in physical
properties after moisture uptake.
Grivory HT3 is an even more advanced
PPA whose moisture uptake has been
minimized.This is important in the elec-
trical and electronic fields when com-
ponents undergo lead-free reflow sol-
dering and functional parts must have
extremely good dimensional stability
(Title photo). In addition, Grivory HT3
is an extremely hydrolysis-resistant and
tough material.During its development,
Ems-Grivory also displayed its concern
for the environment. Grivory HT3 is
produced largely from renewable re-
sources.
Wide Range of Applications
As a materials group, polyphthala-
mides have been known for a long
time and have been successful replace-
ments for metal in numerous applica-
tions in almost all branches of industry.
Typical representatives from Ems-
Grivory include Grivory HT1 (PA6T/6I)
and Grivory HT2 (PA6T/66). These are
used when economical alternatives
to diecast metals such as zinc,aluminum
or brass are required. Technical injec-
tion molded parts made from these
PPA products distinguish themselves
through dimensional stability – even at
high working temperatures of up
to150°C.
PE104325
Ems-Chemie AG
Business Unit Ems-Grivory
CH-7013 Domat/Ems
Switzerland
Tel. +41/81/6 32-6922
www.emsgrivory.com
Manufactureri
Translated from Kunststoffe 8/2008, pp. 111–113

2. 76
COMPOUNDS■
Grivory HT3 is a completely new PPA
polymer that is based on long-chain di-
amines. It exhibits important character-
istics which are further improved com-
pared to those of Grivory HT1 and HT2.
These give it access to fields of applica-
tion from which polyphthalamides have
so far been excluded.
Reduced Moisture Uptake
Until now, polyamides were limited by
the fact that moisture uptake seriously af-
fected material properties.While it is true
that moisture uptake made them
tougher, stiffness and strength were sig-
nificantly reduced. By their nature,
polyphthalamides also absorb moisture,
but to a much lesser degree and much
more slowly. In the case of Grivory HT3,
it has been possible to markedly reduce
moisture uptake to 50% of that of
Grivory HT1. The consequence is that
the new material exhibits exceptional di-
mensional stability and very little ten-
dency to creep.Its physical properties are
essentially unaffected by moisture in the
surroundings.
The long-chain diamines in the poly-
mer chain provide increased hydrolysis
resistance.Thisisclearlydemonstratedby
the extended half-value time after storage
in a water/glycol mixture at 135°C. Elon-
gation at break and tensile stress at break
for Grivory HT3 drop to half their initial
values only after 1,800 h (elongation at
break) and 2,300 h (tensile stress at
break). This corresponds to an increase
inthehalf-valuetimesof 80and50%over
those of the already hydrolysis-resistant
Grivory HT1 GF50 grade (Fig. 1).
With its outstanding elongation and
toughness, Grivory HT3 contradicts the
prevailing opinion that PPA may indeed
be very stiff but is also rather brittle.Even
when highly reinforced,Grivory HT3 is a
tough material with high elongation at
break. As are all polyphthalamides, it is
extremely chemical-resistant and it has
been possible to further improve the per-
formance in hot oil (Fig. 2).
At Home in All Market Segments
Grivory HT is accepted in many applica-
tions encountered in daily life and has
been recognized as a metal replacement
for years. It allows cost-effective produc-
tion of lightweight parts that can with-
standhighmechanical loads –amajorre-
quirement for automotive components.
Its property profile is also appreciated in
this segment for other reasons. The very
good hydrolysis resistance and dimen-
sional stability benefits components that
are in continuous contact with coolants.
Theseincludewaterpumps,radiatorcaps
and expansion tanks. In combination
with exceptionally low permeation, the
goodchemicalresistanceandhightough-
ness predestine Grivory HT3 as a materi-
al for highly stressed connectors in fluid-
conducting systems (Fig. 3).
The electronics industry relies in-
creasingly on miniaturization. Compo-
nents are becoming smaller and smaller
and more complex.At the same time,re-
quirements regarding performance un-
der extreme temperatures and repro-
ducibility are becoming more demand-
ing. Flame retardance is another essen-
tial requirement. Grivory HT3 employs
a halogen and phosphorus-free flame re-
tardant that satisfies the WEEE and
RoHS requirements. It also offers major
benefits during the production process
itself. The halogen and phosphor-free
PPA products on the market to date have
been extremely corrosive when it comes
to barrels, screws and non-return valves
of injection molding machines. Accord-
ingly, a great deal of attention was de-
voted to this aspect during development.
Grivory HT3 is significantly less corro-
sive than previous halogen and phos-
phorus-free flame-retardant polyph-
thalamides on the market. This proper-
ty in particular makes it a favorite inAsia
for the manufacture of connectors. The
first mobile phones with connectors
made of Grivory HT3 are currently be-
ing shipped.
As in the automotive industry, low
moisture uptake and high dimensional
stability play an important role in the
electronics sector. Here, components are
processed at high temperatures using the
so-called reflow soldering process.A high
700 900 1,000 1,500
+50%
+80%
1,800 2,300
2,500
2,000
1,500
1,000
500
0
h
HT1 GF 50 HT1 GF 50
more hydrolysis-resistant
HT3 GF50 H
Time
Elongation at break [MPa]
Tensile stress at break [MPa]
Hydrolysis Resistance
Fig. 1. It has been
possible to increase
the half-value time
for the mechanical
properties of the ex-
tremely low-moisture
PPA Grivory HT3 by
up to 80% compared
to hydrolysis-resist-
ant Grivory HT1
© Kunststoffe
Hydrolysis-
resistance
Chemical
resistance
Impact
strength
Notched
impact strength
StiffnessElongation
Water
uptake
Strength
Grivory HT1
Grivory HT3
Higher/better
Characteristics
Fig. 2. Grivory HT3
distinguishes itself
as an optimum design
material above all
through its low mois-
ture uptake, excel-
lent hydrolysis resist-
ance and outstanding
toughness
© Kunststoffe
© Carl Hanser Verlag, Munich Kunststoffe international 8/2008

3. 77
moisture uptake would result in consid-
erableblisteringduetooutgassingattem-
peratures of up to 260°C. Use of reflow
soldering is much simpler when Grivory
HT3 is involved. It is even possible to at-
tain the highest and very important clas-
sification,JEDEC class 1,for applications
in this sector (Fig. 4).
Grivory HT is suitable for a wide range
of applications in industry and the con-
sumerarea.Thankstoitssignificantlyim-
proved hydrolysis resistance, Grivory
HT3 can be used wherever high temper-
atures and direct contact with water oc-
cur. For instance, it can replace diecast
functional components in coffee ma-
chines, because the material can with-
stand high pressures and temperatures,
and survive the specified number of
brewing cycles. Thanks to it high-tem-
perature capabilities and good resistance
to water, this poses no problems for
Grivory HT3. Product approvals for di-
rect contact with foodstuffs (EU, FDA,
NSF 51) and drinking water (KTW,
W270, ACS, WRAS, NSF 61) are ab-
solutely essential in this regard.
Simple Processing
The Grivory HT3 grade of PPA has a
melting point of 295°C, which is below
that of Grivory HT1 (325°C) and HT2
(310°C). This lower melting point
widens the processing window, so that
the injection molder can operate within
a wide range of process temperatures.
The recommended stock temperature
ranges from 305 to 330°C, with lower
temperatures used for unreinforced
grades of Grivory HT3 and higher tem-
peratures for reinforced grades. The
mold temperature is another important
process parameter. The correct mold
temperature is a prerequisite for pro-
duction of high-quality injection mold-
ed parts with minimal warpage, low in-
ternal stresses and tight dimensional tol-
erance. The recommended mold tem-
perature for Grivory HT3 lies between
115 and 140°C, so that it is possible to
used pressurized water equipment for
mold temperature control.
Many Different Grades
Grivory HT3 is available in heat-stabi-
lized as well as unreinforced and rein-
forced (30 to 50% glass fiber reinforce-
ment)grades.Forapplicationsintheelec-
trical and electronic sectors, glass fiber-
reinforced,halogen andphosphorus-free
flame-retardant products with greatly re-
duced corrosiveness are available. The
material is also approved for applications
involving direct contact with foodstuffs
and drinking water.
Conserving Resources
Grivory HT3 is based to a large extent on
a raw material that is extracted from the
castor bean plant (Rhizinus communis),
a natural and renewable resource.As a re-
sult, after use, only the amount of CO2 is
released that the castor bean plant itself
extracted from the atmosphere during its
growth. Grivory HT3 thus represents the
first commercially available polyphthal-
amide that is based verifiably on a re-
newable resource. ■
THE AUTHOR
DIPL.-ING. (FH) MICHAEL KAISSER, born in 1970,
works in the automotive applications development
department at Ems-Grivory, Domat/Ems, Switzerland;
michael.kaisser@emsgrivory.com
Fig. 3. The outstand-
ing toughness and
good permeation
characteristics pre-
destine Grivory HT3
as a material for con-
nectors in fuel lines
for automobiles
Fig. 4. After reflow
soldering, Grivory
HT3 exhibits no signs
of blistering; compo-
nents achieve the
highest JEDEC
classification
(JEDEC class 1)
COMPOUNDS ■
Kunststoffe international 8/2008
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