Note: Descriptions are shown in the official language in which they were submitted.
~ ~3~ 3
The present invention relates to a metho~ of pro-
ducing shaped bodies from polylaurinlactam as well as the
shaped bodies obtained in accordance therewith.
Uni-ted States Paten-t No. 3,793,255 discloses a
method of producing shaped bodies by -the activa-ted anion:i.c poly-
merisation of la.urinlactam in which two lactam melts are mixed
separately with a ca-talyst and an activator under nitro-
gen respectively and are passed to a mixing arrangement through
separate pipelines maintained at the same temperature as the
melts, and subsequently flow into a mould. The melts, on their
way to the mixing arrangement, flow th.rough respectively a
spiral tube system in siphon-like manner. By this process a
polymer with properties which differ completely from convention-
al polycaprolactam are obtained. The disadvantage of this
method is however, tha-t serviceable polymerised cast products
can lndeed be initially obtained, but the properties thereof
~ deteriorate very severely after a short space of time.
; German Offenlegungsschrift No. 2,507,549 discloses
` a method of p~oducing shaped bodies from polylactams, more
especially polylaurinlactam, in which the monomeric lactam is
melted, the melt is initially intermixed with a catalyst, the
mixture obtained is mixed with an activator and the polymerised
; product is cast immediately afterwards into molds.
A modification of this method is described in
German Offenlegungsschrift No. 2,559,749, according to which
polylaurinlactam shaped bodies are produced by the method
in which together with stirring, a polymerisation catalyst is
added, at a temperature above 160C and below 170C, to a
, ~ .
partial lactam melt in a separate boiler and the mixture is
stirred. An activator is then added, with stirrin~, at a
temperature which lies a few C lower than that of the first
melt but which likewise lies in the range from below 170 C to
- 1 --
above 160C, to an equivalen-t par-tial lactam melt whlch is in
a separate boiler, and is stirred. The melts obtained are,
with maintenance of their temperatures, in each case drawn
off by a gear pump from their xespective boilers and axe passed
through gently inclined pipelines, which have a volume which
is greater by at least 1/3rd than that which corresponds to
the delivery capacity of the pump, to the mixing zone, where
they are mixed at a temperature from 170 C to 175 C and are
injection moulded or cast through a spraying head without
pressure or at low pressure. The polylaurinlactam products
obtained in accordance with German Offenlegungsschrifts Nos.
2,507,549 and 2,559,749 have the following physical character-
istics:
'; (a) a yield stress ~, measured in accordance with DIN 53,455,
'~ from approximately 470 to about 520 kp/cm2;
' (b) an elongation, measured in accordance with DIN 53,455,
:' upon yield stress ES from approximately 17 to approximately
'' 25 percent;
(c) a -tear strength 6R, measured in accordance with ISO R 527,
' 20 from approximately 500 to approximately 630 kp/cm2;
~' (d) a tear elongation ~R~ measured in accordance with ISO R
527, from approximately 200 to 350 percent;
(e) a modulus of elasticity E, measured in accordance with
DIN 53,457 Para 2.3, from approximately 19,000 to approxi-
mately 22,000 kp/cm2;
(f) a limiting bending stress ~B' measured in accordance with
ISO R 178, from approximately 750 to approximately 1,000
kp/cm ;
(g) a notched bar impact strength aK, measured in accordance
with DIN 53,453, from approximately 55 to 65 kpcm/cm ;
(h) a ball thrust hardness 10", measured in accordance with
; DIN 53,456 stage C, from approximately 1,000 to approxi-
.~ - 2 -
`` 3 ~
mately 1,050 kp/cm ;
(i) an abrasion resistance, measured by means of Taber-Abrazer,
from approximately 158 to approxima-tely 129 mm3/Upm;
(j) a creep rate stress ~1/1,000 (23C/95 percent), measured
in accordance with DIN 53,444, from approximately 50 to
approximately 60 kp/cm ; and
(k) a creep modulus EC/1,000 (~20.0), rneasured in accordance
with DIN 53,44~, from approximately 13,000 to approximately
. 1~,000 kp/cm2.
Furthermore, German Offenlegungsschrift No. 2,602,
312 discloses a thread casting installation in which the
aforesaid polylaurinlactam melts above can be cast into threads.
The present invention provides a method which is
simple and which is smoothly feasible and which yields poly-
laurinlactam shaped bodies having improved physical properties.
It has now been surprisingly found that, when the
polylaurinlactam material of the above-mentioned Offenlegungs-
schrifts and which does not melt upon the heating, but decom-
poses in air at a temperature in the range from approximately
20 217 to 271 C and is no longer regenerable is distributed into
a granulated materlal and this granulate-shaped material is
shaped in the injection moulding process into shaped bodies,
products having improved properties are obtained.
The present invention thus provides a method of
producing shaped bodies from polylaurinlactam in which laurin-
i~ lactam is melted, the melt is initially intermixed with a
catalyst and then the mi~ture is mixed with an activator and
is polymerised, the polymerising material is cast into threads
or strands of a polymer which does not melt upon the heating,
but decomposes at temperatures in the range from approximately
217 to 271C in air and is no longer regenerable, the threads
or strands are comminuted into granulated material or chips
- 3 -
:
and the comminu-ted ma-terial is injection moulded at temperatures
from 220 to 255C at pressures from 50 to 100 kp/cm2.
The present invention also provides the polylaurin-
lactam shaped bodies obtained by the method of the present in-
vention. The polylaurinlactam shaped bodies of the invention
have the following physical properties:
(a) a yield stress ~S' measured in accordance with DIN 53,455,
from approximately 480 to approximately 500 kp/cm2;
(b) an elongation, measured in accordance with DIN 53,445,
upon yield stress S from approximately 28 to 36 percent;
(c) a tearing strength ~R~ measured in accordance with ISO R
.~ 527, from approximately 550 to approximately 670 kg/cm ;
(d) A tearing elongation ER me sured in accordance with ISO R
~ 527, from approximately 220 to approximately 330 percent;
~ (e) a modulus of elasticity E, measured in accordance with
DIN 53,457 Para 2.3, from approxima-tely 20,000 to approxi-
mately 24,000 kp/cm2;
(f) a limiting bending stress 6B, measured in accordance with
ISO R 178, from approximately 730 to approximately 920
kp/cm2;
(g) a notched bar impact strength aK, measured in accordance
with DIN 53,453, from approximately 70 to approximately
85 kpcm/cm2; and
. (h) a ball thrust hardness from (of?) 10", measured in accord-
ance with DIN 53,456 stage C, from approximately 1,030
: to 1,060 kp/cm .
The polylaurinlactam obtained in accordance with
German Offenlegungsschrift No. 2,507,54g or German Offenlegungs-
`. schrift No. 2,559,749 may be used as starting material for
effecting the method in accordance with the invention.
To produce the starting material, initially laurin-
lactam is melted and the catalyst is mixed into this melt. After
- 4 -
;
33~3:,
-thorough intermixing, the ac-tivator is added to the mixture.
The addi-tion oE -the catalyst -to -the laurinlactam melt, the
subsequent admix-ture of the activator and the polymerisa-tion
are preferably effected at a constant temperature, advantageous-
ly in the range from 150 to 200C, in which respect a tempera-
.~`; ture of 160C has proved to be optimum.
One may also in accordance with German Offenlegungs-
schrift No. 2,559,749 proceed in such a way that equivalent
~. . quantities of laurinlactam are introduced into two separate
boilers and are melted with s-tirring. Whilst maintaining a
temperature below 170C and above 160 C, a catalyst is intro-
. duced into one boiler and stirred. Subsequent to this an
: activator is added with stirring to a separate boiler, which
; has an equivalent quantity of lactam melt, at a temperature
which lies a few C below that of the first melt, but also
within the range from below 170 C to above 160 C. The contents
of two containers are then drawn off, with maintenance of their
temperatures, in each case through a gear pump out of their
boilers and passed from the two gear pumps through pipelines
: 20 with a maximum inclination to the horizontal of 10 to a mixing
zone, the pipelines have a volume which is greater by at least
one-third than the delivery capacity of the pump. The material
~ is briefly intermixed in the mixing zone.
.. ~ In accordance with the invention, the polymerising
material is cast immediately into threads or strands. For
example the thread casting apparatus disclosed in German Patent
No. 2,602,312 can be used for this operation. The threads or
strands are then comminuted into a granulated material or into
chips. For example the threads or strands can initially be
processed by ro:Lling into bands which are then cut into strips
and finally comminuted into granulated material. Conventional
mills or granulating machines can be used for comminuting the
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,
polymer. The ~ranulated materials can have any desired, uniform
or non-uniform shapes~ For example, the granulated material
used may have a rectangular, more especially square cross-
section. Preferably the granulated material used has an average
particle diameter of 2 to 5 mm. A cubic granulated ma-terial
having edge lengths of 3 mm proved to be particularly Eavour-
able.
The polylaurinlactam granulated material intermediate
product is then injection moulded. In this respect, -tempera-
10 tures from 220 to 255C as well as pressures from 50 to 100
kp/cm are used. The moulding operation can be effected in
conventional injection moulding machines having heated extruder
worms and nozzles. Preferably the rear region of the worm is
- heated to a temperature of 240 C, whilst the front re~ion of
~-~ the worm is heated to a temperature of 250 C. The nozzle
heating lies preferably at a temperature of 250 C.
The production of the polylaurinlactam shaped body
'~
in accordance with the invention can be effected, for example,
in the following manner.
In accordance with the method described in German
Offenlegungsschrift No. 2,507,549 or German Offenlegungsschrift
No. 2,559,749, from laurinlactam there is produced a polymerisa-
tion product which is supplied in the polymerising state, advan-
tageously at temperatures from 160 to 168 C, to a thread cast-
ing installation. Advantageously the polymerising material is
conducted by a pump into a thread casting installation includ-
ing a discharge traverse for the continuous casting of threads
or strands. The polymerisation product then emerges as a
liquid, thread-shaped material from the thread casting installa-
tion and passes over a half-open guide channel, for example as an
approximately round-profiled liquid plastics thread, to a set
of mixing rollers, the roll gap of which is continuously vari-
.~
able and is rolled to the desired thickness and wid-th. The
band passing ou-t oE the roll gap by way of a guide channel is
then cut upon passage through cutter rollers into parallel
strips, which are then comminuted by a subsequently-arranged
cutter head of a cutter roller into granulated material or
chips. For example, the granulated materials have, by virute
- of a square cross-section of the strips, the shape of a cube.
The granulated materials or chips are, after passage through
a dust removal device, passed to an injection moulding machine.
Where granulated material is injection moulded, using heated
extruder worms and heated nozzles, with application of pressure.
The temperatures used are between 220 and 255C, whilst pres-
sures are from 50 to 100 kp/cm . The granulated material can
be injection moulded into any desired shaped bodies.
The polylaurinlactam shaped bodies obtained in
accordance with the method of the invention have excellent prop-
erties, in which they are superior to the previously-known
~ polylaurinlactam materials.
- The mechanical and thermal properties of the material
.
in accordance with the invention are collated in the following
Tables I and II.
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Table
,
Mechanlcal properties Measuring Dirnension
Method
~ . . ... _
Yield stress ~S DIN 53,455 kp/cm 480 - 500
Elongation upon DIN 53,455 percent 28 - 36
yield stress ~S
Tearing strength ~R ISO R 527 kp/cm 550 - 670
; Tearing elonqa-tion ER ISO R 527 percent 220 330
Modulus of elastlci-t~ E DIN 53,457 kp/cm 20000 - 24000
; lO Para. 2.3
Limiting bending ISO R 178 kp/cm730 - 920
stress ~B
Notched bar impact DIN 53,453 kpcm/cm 70 - 84
I strength aK
Ball thrus-t hardness lO" DIN 53,456 kp/cm1030 - 1060 ¦
; _ Stage C _ l - --- -J
Table II
.
Thermal properties Measuring Me-thod I Dimension
__._ _ _ ._ ._
Decomposition temp-
lerature in the Depending on C~200 ~ 260
atmosphere recipe
Melting tempera- VICAT ~ DIN C 194
ture 53,46 n
Coefficient of linearat -600to 10 / C0.3 - 0.5
expansion ~ ~30 C
Coefficient of ther- kcal/m.h. 0.24
mal conductivity ~ - grd
Temperature limits up to some hours o 210
of the use up to 4 months C 160
¦up~7ards up to years C 135
._ . _ __ . . _ .
The polylaurinlactam shaped bodies in accordance
- 30 with theinvention stand out in an advantageous manner from the
properties of previously know~ polyamides. In the Figs. 1 to
9 of the accompanying drawings, the properties of the product
- 8 -
~.:.il.ti&.~ ~
of Ihe presen-t lnvention are compared on the one hand with
those of the polylaurinlactam product, us~d as starting ~t
material, in accordance with German OffenlegungsschriEt No.
2,507,5~9 and on the other hand with those of other known
polyamides such as polyamide 12, polvamide 11, polyamide 6.6
and polyamide 6. As can be seen , the product in accordancc
~ith the invention combines excellent elonclation upon yield
stress, tearing strength, excellent modulus of elasticity,
.. notched bar impact strength and ball thrust hardness with
good yield stress, tearing elongation and limiting bending
stress with extremely slight shri.nkage of the ma-terial.
Furthermore, the polylaurinlactam shaped bodies
in accordance with the invention have excellent compressive
strength. As shown in rig. 10 which, as the result of
compression tests, is a force - upsetting diagram of the
polylaurinlactam material in accordance with the invention.
To carry out the compression tests, five cubes obtained from
the polylaurinlactam shaped body produced in accordance with
the invention and having an edge length of 25 mm were used
as test bodies which were tested using a universal testing
machine 200 kN whilst adhering to a test climate of 23 C/50
percent relative air moisture and a deformation speed of
2.0 mm/min. The compression tests are reproduced in Table
III.
3~ 9
Table III
Compression Tests
_ I -- ---------r----------
Test piece ~i /o 1~ ~s 2) ~10 o/o 3) 1 ~ s 4)
No. N/mm N/mmN/mm i O/O
" . ._ _ .. __ _
~; 1 17.01 45.76 ~8.73 2.71
2 15.95 45.23 56.74 2.91
3 17.44 49.5~3 61.81 2.91
4 17.~1 50.6t) 64.09 ~.95
~ 5 17.68 46.73 57.97 2.91
- Average ]7.06 47.58 59.87 2.83
1) Compressive stress at 1 percent upsetting.
2) Compressive stress at upsetting limit, in which
respect the upsetting limit was ascertained as the point of
intersection of the two main equalising straight lines onto
the curve (see Fig. 10).
` 3) Compressive stress at 10 percent upsetting.
.. ~
4) Elongation at upsetting limit.
As result of the compressive tests, in no test body
was a failure or breakage ascertained during and after the
tests.
The compressive test was terminated at a compressive
force of 60 kN, or respectively at a compressive s-tress of
about 96 N/mm .
The new polylaurinlactam shaped bodies in accordance
with the invention are also distinguished by a high resistance
to light energy radlation.
In a surprising manner it has furthermore been
ascertained that the mechanical propertles of the polylaurin-
lactam meterial in accordance with the invention are improved
, by irradiation with light energy radiation. As can be seen
from the following Table IV, four test pieces of the material
in accordance with the invention were irradiated with Y-radia-
tion.
-- 1.0 --
Table IV
Irradiation of the polylaurinlactam material in accordance with
the invention with Y-rays.
~ J
Irradiated material in accordance Energy dose
with the invention
,~ I 1 not irradiated (1)
2 40 ~ 10 J/kg
~ 3 100 ~ 104 J/kg
4 200 ~ 10 J/kg
:' !
(1) as comparison base value
The irradiated test pieces 2 to 4 as well as the non-
irradiated reference sample were tested with respect to their
mechanical properties. The values obtained are reproduced in
the following Table V.
Table V
Mechanical properties of the polylaurinlactam material in accord-
ance with the invention after irradiation with Y-radiation.
Test Standard ¦ Unit ¦Reflerl 2 3 ~ 4
. _ _ I l , I
Shore D DIN 53505 _ 69 71 71 72
Tensile strength 2
at the flow limit DIN 53455 N/mm 50 52 55 54
Elongation at the
flow limit DIN 53455 o/o 38 20 18 14
Breaking 2
strength DIiN 53455 N/mm 50 52 55 53
Breaking
elongation DIN 53455 o/o 38 20 18 14
Bending-E-
modulus DIN 53452N/mm21230 1425 1615 1735
Limiting bend- 2
ing strengthDIN 53452N/mm81 85 86 92
.. .__ .. _ .. _ ...
The increase in the mechanical properties of the poly-
; aurinlactam material, in accordance with the invention, after
erradiation with Y-rays is reproduced as a graph as a function
of the ray dose in Fig. 11.
'~
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