Note: Descriptions are shown in the official language in which they were submitted.
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23443-463
MOULDING COMPaSITIONS WHICH ARE STABLE
TO ALCOHOLS AND BOILING WATER
The invention relates to moulding compositions which
are based on amorphous copolyamides and are stable to alcohols
and boiling water.
Moulding compositions which are based on amorphous
polyamides and are stable to boiling water are known (European
Patents 50 742 and 69 700 and German Patent 3 600 015). However,
these moulding compositions have a crucial disadvantage as far
as their serviceability is concerned - they are not stable to
alcohols, such as, for example, methanol, ethanol, propanols,
butanols and the like. As the case may be, they tend to become
turbid, to swell or to become tacky in the presence of alcohols;
in some cases, they are completely soluble in alcohol. However,
for many applications, such as, for example, for spectacle
frames or viewing windows in apparatuses, stability to alcohols
is an essential prerequisite.
The object of the invention was to provide moulding
compositions which do not have the above-mentioned disadvantages,
but without losing their other advantageous properties.
This object may be achieved by means of compositions
using the copolyamides according to the invention.
Thus, according to one aspect, the invention provides
a moulding composition which is stable to alcohols and boiling
water, which comprises an amorphous copolyamide obtained by
polycondensing
A. 1. 50 - 99.5 mol-% of isophthalic acid
2. 0.5 - 50 mol-% of dodecanedicarboxylic acid with
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23443-463
B. 1. 10 - 50 mol-% of decamethylenediamine
2. 50 - 90 mol-% of bis(4-aminocyclohexyl)methane.
According to another aspect, the invention provides an
amorphous copolyamide obtained by polycondensing
A. l. 50 - 99.5 mol-% oE isophthalic acid
2. 0.5 - 50 mol-% of dodecanedicarboxylic acid with
B. 1. 10 - 50 mol-% of decamethylenediamine
2. 50 - 90 mol-% of bis(4-aminocyclohexyl)methane.
Preference is given to moulding compositions based on
copolyamides obtained by polycondensing
A. 1. 50 - 99.5 mol-% of isophthalic acid
2. 0.5 50 mol-% of dodecanedicarboxylic acid with
B. 1. 20 - 50 mol-% of decamethylenediamine
2. 50 - 30 mol-% of bis(4-aminocyclohexyl)methane.
A further preferred embodiment uses copolyamides in
which up to 50 mol-% of the isophthalic acid has been replaced
by terephthalic acid. It is furthermore possible to replace
some or all of the bis(4-aminocyclohexyl)methane by its methyl
derivative, bis(3-methyl-4-aminocyclohexyl)methane.
Decamethylenediamine is ta]~en to mean any aliphatic
diamine having the empirical formula CloH24N2 whose amino groups
are separated by at least 7 to 10 CH2 units. Diamines may be
employed individually or as a mixture.
The copolyamides on which the moulding compositions
according to the invention are based have a relative solution
viscosity (nrel) in the range from 1.4 to 2.1, preferably in the
range from 1.50 to 1.95. The glass transition point (T ) of the
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2 ~
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23443-463
copolyamides is in the range from 120 to 180C, preferably in
the range from 140 to 170C.
The preparation of the copolyamides is known in
principle. The polycondensation of the components is carried
out in the melt. The preparation may optionally be carried out
in the presence of a phosphorus-derived acid of the general
formula H3POn where n = 2 to 4 or triphenyl phosphite.
Suitable phosphorus-derived acids are hypophosphorus
acid, phosphorus acid and phosphoric acid.
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If a catalyst is added, it is employed in an amount of
from 0.001 to 1 mol-%, preferably from 0.001 to
0.1 mol-~, based on the sum of all the monomers.
The reaction is carried out in the melt at a temperature
in the range from 200 to 350C, preferably from 210 to
320C.
The reaction is u~ually carried out under an inert gas at
atmospheric pressure, but may also be carried out under
superatmospheric pre sure or reduced pressure.
In order to increase the molecular weight, the copoly-
amides may be subjected ~o solid-phase postcondensation
in an inert-gas atmosphere.
The copolyamides are converted into moulding compositions
in conventional machines by injection moulding or
extrusion.
The moulding compositions may additionally contain
fillers, such as talc, or reinforcing agents, such as
glass fibres, ARAMIDR ~ibres or carbon fibres, and other
conventional additives, such as, for example, pigments or
stabilisers.
The moulding compositions are converted into mouldings,
fibres, films, etc., by conventional processes, such as
injection moulding, extrusion or the like.
The moulding compositions according to the invention have
surprisingly high stability to alcohols without Lmpair-
ment of their good general properties, in particular the
stability to boiling water.
The parameters mentioned in the description and the
examples were determined using the methods ~elow.
The relative solution viscosity (~r~l) was determined on
2 ~ 6 2
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0.5 % strength by weight polyamide solutions in m-cresol
at 25C.
The glass transition temperature (T8) results from DSC
measurements at a heating xate of 20 K/min.
Examples
~m~
Starting materials: 4.984 kg of isophthalic (30 mol)
acid
4.606 kg of dodecane- 120 mol)
dicarboxylic acid
2.5~5 kg of n-decamethylene- (15 mol)
l,lO-diamine
7.362 kg of bis(4 amino- (35 mol)
cyclohexyl)methane
17.000 kg of water
0.340 g of H3PO2 (as a 50 ~ strength
by weight aqueous solution)
The starting materials were dissolved in water under
nitrogen in a polycondensation reactor at 170C and at a
pressure of 9 bar. The temperature of the reaction
mixture was raised to 230C while maintaining the
pressure,and then stirred at this temperature for 1 hour.
The temperature was subsequently raised to 300C. The
water liberated was remo~ed by distillation. After 4
hours at 300C, the copolyamide was discharged from the
reactor.
~7rel = 1 . 65 T8 = 149 C
Example 2
St~rting materials: 2.492 kg of isophthalic ~15 mol~
acid
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2.492 kg of terephthalic (15 mol3
acid
4.606 kg of dodecane (20 mol)
dicarboxylic acid
2.585 kg of n-decamethylene- (15 mol)
l,10-diamine
7.362 kg of bi~(4-amino- (35 mol)
cyclohexyl)methane
17.000 kg of water
0.340 g of H2PO2 (as a 50 % strength
by weight aqueous solution)
The polycondensation was carried out analogou~ly to
Example 1.
~rel = 1 54 Tg = 153~C
Example 3
Starting materials: 4.984 kg of isophthalic (30 mol)
acid
4.606 kg of dodecane- (20 mol)
dicarboxylic acid
:: 20 2.585 kg of n-decamethylene- (15 mol)
1,10-diamine
: 8.342 kg of bis(3-methyl- (35 mol)
4-aminocyclohexyl)methane
18.000 kg of water
0.300 g of H3PO2 (as a 50 % strength
by weight aqueous solution)
The polycondensation was carried out analogously to
Ex~mple 1.
~ral = 1.50 Tg = 163C
Example 4
The copolyamides prepared a~ per Examples 1 to 3 were
, . , -: :. ,
~. - ~ - , . .
. . .
,, - ~ .
- .,
" , ~
'
2 0 ~ ~ ~ 6 ~
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compared with two commercially available copolyamides (A)
and (B) said to be stable to boiling water.
Copolyamide (A) (TROGAMIDB T) contains as monomers
terephthalic and trimethylhexamethylenediamine (isomer
mixture comprising approximately equal parts by weight of
2,4,4- and 2,2,4-trimethylhexamethylenediamine).
Copolyamide (B) (GRILLAMIDR T~ 55) comprises about
30 mol-% of isophthalic acid, about 30 mol-% of 3,3'-
dimethyl-4,4'-diaminodicyclohexylmethane and about
40 mol-% of laurolactam as monomers.
The copolyamides according to the invention and the
comparison products were stored in ethanol for 3 weeks at
room temperature. While tha copolyamides according to the
invention were unchanged in appearance and solution
viscosity, the comparison products became tacky after
only a few hours. The boiling water test (24 hours in
boiling water) likewise caused no change in the copoly-
amides according to the invention, while copolyamide (A)
became very turbid and copolyamide (B) slightly turbid.
