PROCEDE DE PRODUCTION DE RESINE POLYAMIDE-IMIDE A HAUT POIDS MOLECULAIRE

PROCESS FOR THE PRODUCTION OF HIGH MOLECULAR WEIGHT POLYAMIDE-IMIDE RESIN

Abrégé anglais

ABSTRACT OF THE DISCLOSURE
High molecular weight polyamide-imides having a
reduced viscosity of 0.3 dl/g or above and exhibiting
excellent heat resistance and melt flowability is produced
with good economic efficiency by a process, which process
comprises the two reaction stages:
(a) a first reaction stage which comprises reacting (I) a
trimellitic acid derivative and (II) an aromatic
diamine in the presence of a polar solvent in the
presence of a first dehydration catalyst until a
polyamide-imide resin having a reduced viscosity of
0.2 to 0.5 dl/g as measured at a concentration of 0.5
g/dl in dimethylformamide at 30°C is produced; and
(b) a second reaction stage which comprises adding a
phosphorous ester as a second dehydration catalyst to
the reaction mixture resulting from the first reaction
stage and further reacting the reaction mixture until
a high molecular weight polyamide-imide resin having a
reduced viscosity of 0.3 dl/g or above as measured at
a concentration of 0.5 g/dl in dimethylformamide at 30
°C is produced.

Revendications

Claims:
1. A process for producing high molecular weight
polyamide-imide resin having a reduced viscosity of 0.3 dl/g
or above by reacting a trimellitic acid derivative (I)
selected from the group consisting of trimellitic acid
anhydride and an ester of trimellitic acid or trimellitic
acid anhydride with an alcohol and an aromatic diamine (II),
in the presence of a polar solvent and dehydration catalyst,
which process comprises the two reaction stages:
(a) a first reaction stage which comprises reacting
the trimellitic acid derivative (I) and the
aromatic diamine (II) in the presence of a polar
solvent in the presence of a first dehydration
catalyst selected from the group consisting of
boric acid, boric anhydride, phosphoric acid,
pyxophosphoric acids, metaphosphoric acid,
ethylmetaphosphoric acid, polyphosphoric acid,
phosphorus pentoxide, and phosphonic pentachloride
at a temperature ranging from about 195°C to about
205°C until a polyamide-imide resin having a
reduced viscosity of 0.2 to 0.5 dl/g as measured
at a concentration of 0.5 g/dl in
dimethylformamide at 30°C is produced; and
(b) a second reaction stage which comprises adding a
phosphorus triester as a second dehydration
catalyst to the reaction mixture resulting from
the first reaction stage and further reacting the
reaction mixture at a temperature ranging from
26

about 180°C to about 190°C until a high molecular
weight polyamide-imide resin having a reduced
viscosity of 0.3 dl/g or above as measured at a
concentration of 0.5 g/dl in dimethylformamide at
30°C is produced; the first dehydration catalyst
being used in an amount of 0.5 to 20% by weight on
the basis of the total of the trimellitic acid
derivative (I) and the aromatic diamine (II), and
the phosphorus triester as a second dehydration
catalyst being used in an amount of 0.1 to 50% by
weight on the basis of the total of the
trimellitic acid derivative (I) and the aromatic
diamine (II).
2. The process of claim 1, wherein the first
dehydration catalyst is selected from the group consisting
of phosphoric acid, polyphosphoric acids, boric acid, and
boric anhydride.
3. The process of claim 2, wherein the first
dehydration catalyst is phosphoric acid.
4. The process of claim 1, wherein the phosphorous
triester as a second dehydration catalyst is selected from
the compounds having the structure represented by the
following general formula:
(RO)3P
wherein
27

R is selected from the group consisting of methyl,
ethyl, isopropyl, butyl, 2-ethylhexyl, isooctyl,
decyl, lauryl, phenyl, methylphenyl, ethylphenyl,
butylphenyl, octadecylphenyl, nonylphenyl,
diphenylnonyl, biphenylyl, cyclohexyl, and
indenyl.
5. The process of claim 4, wherein the phosphorous
triester as a second dehydration catalyst is triphenyl
phosphite.
6. The process of claim 1, wherein the first
dehydration catalyst is used in an amount of 1 to 5 % by
weight on the basis of the total of the trimellitic acid
derivative (I) and the aromatic diamine (II), and the
phosphorous triester as a second dehydration catalyst is
used in an amount of 3 to 30% by weight on the basis of the
total of the trimellitic acid derivative (I) and the
aromatic diamine (II).
7. The process of claim 1, wherein the trimellitic
acid derivative (I) is trimellitic acid anhydride.
8. The process of claim 1, wherein the aromatic
diamine (II) is selected from the group consisting of 4,4'-
diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, p-
phenylenediamine, and m-phenylenediamine.
28

9. The process of claim 8, wherein the aromatic
diamine (II) is 4,4'-diaminodiphenylmethane.
10. The process of claim 1, wherein the polar solvent
is selected from the group consisting of N-methylpyrrolidone,
N-ethylpyrrolidone, N-butylpyrrolidone, phenol, cresols,
xylenols, .lambda.-butyrolactone, and sulfolane.
11. The process of claim 10, wherein the polar solvent
is N-methylpyrrolidone.
12. A process for producing high molecular weight
polyamide-imide resin having a reduced viscosity of 0.3 dl/g
or above by reacting a trimellitic acid derivative (I)
selected from the group consisting of trimellitic acid
anhydride and an ester of trimellitic acid or trimellitic
acid anhydride with an alcohol and an aromatic diamine (II),
and one or more compounds (III) selected from the group
consisting of (A) dicarboxylic acids and (B) lactams, in the
presence of a polar solvent and dehydration catalyst, which
process comprises the two reaction stages:
(a) a first reaction stage which comprises reacting
the trimellitic acid derivative (I) and the
aromatic diamine (II), and one or more compounds
(III) selected from the group consisting of (A)
dicarboxylic acids and (B) lactams, in the
presence of a polar solvent in the presence of a
first dehydration catalyst selected from the group
29

consisting of boric acid, boric anhydride,
phosphoric acid, pyrophosphoric acids,
metaphosphoric acids, ethylmetaphosphoric acid,
polyphosphoric acid, phosphorus pentoxide, and
phosphoric pentachloride at a temperature ranging
from about 195°C to about 205°C until a polyamide-
imide resin having a reduced viscosity of 0.2 to
0.5 dl/g as measured at a concentration of 0.5
g/dl in dimethylformamide at 30°C is produced; and
(b) a second reaction stage which comprises adding a
phosphorus triester as a second dehydration
catalyst to the reaction mixture resulting from
the first reaction stage and further reacting the
reaction mixture at a temperature ranging from
about 180°C to about 190°C until a high molecular
weight polyamide-imide resin having a reduced
viscosity of 0.3 dl/g or above as measured at a
concentration of 0.5 g/dl in dimethylformamide at
30°C is produced; the first dehydration catalyst
being used in an amount of 0.5 to 20% by weight on
the basis of the total of the trimellitic acid
derivative (I) and the aromatic diamine (II), and
the one or more compounds (III) and the phosphorus
triester as a second dehydration catalyst being
used in an amount of 0.1 to 50% by weight on the
basis of the total of the trimellitic acid
derivative (I) the aromatic diamine (II) and the
one or more compounds (III).

13. The process of claim 12, wherein the first
dehydration catalyst is selected from the group consisting
of phosphoric acid, polyphosphoric acids, boric acid, and
boric anhydride.
14. The process of claim 13, wherein the first
dehydration catalyst is phosphoric acid.
15. The process of claim 12, wherein the phosphorous
triester as a second dehydration catalyst is selected from
the compounds having the structure represented by the
following general formula:
(RO)3P
wherein
R is selected from the group consisting of methyl,
ethyl, isopropyl, butyl, 2ethylhexyl, isooctyl,
decyl, lauryl, phenyl, methylphenyl, ethylphenyl,
butylphenyl, octadecylphenyl, nonylphenyl,
diphenylnonyl, biphenylyl, cyclohexyl, and
indenyl.
16. The process of claim 15, wherein the phosphorous
triester as a second dehydration catalyst is triphenyl
phosphite.
17. The process of claim 12, wherein the first
dehydration catalyst is used in an amount of 1 to 5% by
weight on the basis of the total of the trimellitic acid
derivative (I), the aromatic diamine (II) and one or more
31

compounds (III), and the phosphorous triester as a second
dehydration catalyst is used in an amount of 3 to 30% by
weight on the basis of the total of the trimellitic acid
derivative (I), the aromatic diamine (II), and one or more
compounds (III).
18. The process of claim 12, wherein the trimellitic
acid derivative (I) is trimellitic acid anhydride.
19. The process of claim 12, wherein the aromatic
diamine (II) is selected from the group consisting of 4,4'-
diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, p-
phenylenediamine, and m-phenylenediamine.
20. The process of claim 19, wherein the aromatic
diamine (II) is 4,4'-diaminodiphenylmethane.
21. The process of claim 12, wherein the dicarboxylic
acids (A) are succinic acid, adipic acid, sebacic acid,
dodecanecarboxylic acid, isophthalic acid, and terephthalic
acid.
22. The process of claim 12, wherein one or more of
the dicarboxylic acids (A) are used in an amount of 0.05 to
0.50 mol per 1 mol of the aromatic diamine (II).
23. The process of claim 22, wherein one or more of
the dicarboxylic acids (A) are used in an amount of 0.1 to
0.3 mol per 1 mol of the aromatic diamine (II).
32

24. The process of claim 12, wherein the lactams (B)
are compounds represented by the following general formula:
<IMG>
wherein n is an integer of 2 to 20.
25. The process of claim 12, wherein one or more of
the lactams (B) are used in an amount of 0.05 to 0.50 mol
per 1 mol of the aromatic diamine (II).
26. The process of claim 25, wherein one or more of
the lactams (B) are used in an amount of 0.05 to 0.30 mol
per 1 mol of the aromatic diamine (II).
27. The process of claim 12, wherein the compound
(III) is isophthalic acid.
28. The process of claim 12, wherein the compound
(III) is .epsilon.-caprolactam.
29. The process of claim 12, wherein the compounds
(III) are isophthalic acid and .epsilon.-caprolactam.
30. The process of claim 12, wherein the polar solvent
is selected from the group consisting of N-methylpyrrolidone,
N-ethylpyrrolidone, N-butylpyrrolidone, phenol, cresols,
xylenols, .lambda.-butyrolactone, and-sulfolane.
33

31. The process of claim 30, wherein the polar solvent
is N-methylpyrrolidone.
32. The process of claim 1, wherein the first reaction
stage and the second reaction stage are carried out in an
atmosphere of an inert gas.
33. The process according to claim 32, wherein the
inert gas is nitrogen.
34. The process according to claim 12, wherein the
first reaction stage and the second reaction stage are
carried out in an atmosphere of an inert gas.
35. The process according to claim 34, wherein the
inert gas is nitrogen.
34

Description

1315463
PROCESS FOR THE PRODUCTION OF HIGH MOLECULAR WEIGHT
POLYAMIDE-IMIDE RESIN
BACKGROUND OF THE INVENTION
(a) Field of the Invention
The present invention relates to processes for
producing polyamide-imide resins and, more particularly, it
relates to economical processes for producing high molecular
weight polyamide-im.ide resins exhibiting excellent heat
resistance and melt flowability.
(b) Description o~ the Related Art
As methods of producing polyamide-imides,
:; a solution polymerization method with aromatic
: : dilsocyanates (see Japanese Patent Application Publication
No. 48-19274), a precipitation polymerization method with
aromatic diisocyanates (see Japanese Patent Application
Publicatlon No. 54-44719), a solution polymerization method
with pyromellitic acid chlorides (see Japanese Patent
~ Applicatîon Publication No. 42-15637), and a solution
: polymerization method with aromatic diamines (Japanese
Patent Application Publication No. 49-4077) are Xnown. In
the oase o~ the solution polymerization method with aromatic

2 1315463
diisocyanates, undesirable side reactions tend to occur from
the start of polymerization causing a dif~iculty in
production of linPar polymers having high molecular weight.
The polymers produced by the method are therefore too poor
in melt flowability to be suitable for the use of molding
materials or the liXe.
Precipitation polymerization method with aromatic
diisocyanates has problems in safety in working environment
and cost since reaction is carried out using highly
poisonous nitro compounds or expensive sulfolane type
solvents. Further, the method, due to it's difficulty in
controlling molecular weight, has difficulty in quality
control of the product. Furthermore, the method tends to
induce side reactions like the above-described solution
I5 polymerization method with aromatic diisocyanates, and
there~ore the produced polymers are also inferior in melt
flowability. A solution polymerization method with
pyromellitic acid chlorides is disadvantageous in cost since
it needs a step for purifying the by-produced halogen
compounds. Further, in case of producing modified polymers,
the method has such a disadvantage as the restriction in
materials to be used.
On the other hand, a solution polymerization method
with aromatic diamines is free from these problems and is a
useful method well-balanced in cost and melt flowability
c~t~

` 1315~63
l and heat resistance of the product polymers. The method i5
practically carried out using a dehydration catalyst, ror
example, phosphoric acid type catalysts such a~ phosphoric
acid and polyphosphoric acid, borlc acid type catalysts
such as boric acid and boric anhydride, and phosphorous
triesters such as triphenyl phosphite. It is known that
catalytic effects of these catalysts substantially dif-fer
according to the kind thereo~.
That is, wh:Lle a single catalyst system o-f
phosphoric acld, polyphosphoric acid or boric acid can
exhibit sufficient catalytic effect with a small amount, it
however needs a long time reaction at a high temperature of
200C or more. Therefore, even if N-methylpYrrolidone
(boiling point: 202C ), which is a high boiling point
solvent, is used as the solvent for synthesis, there will
~requently occur un~esirable phenomenon that the generating
resins havi~g high molecular weight and high viscosity are -
baked or stuck to the surface of reactor wall irl the course
of the hi~h temperature and long time synthetic process.
While a slngle catalyst system of phosphorous tries$ers can
achieve high molecular weight polymerization in a reaction
at a relatively low temperature of 190C or less, it lS
required in an amount equivalent to the amount of the
condensation-reactive groups of the acid component or amine
component, and the use of a large quantity of expensive

13t5463
catalyst causes problems of cost and difficulty in
controlling molecular weight.
SUMMARY OF THE INVENTION
An object of the present invention is to solve the
problems of the conventional methods descr-ibed above and to
provide an economical process for producing high molecular
weight polyamide-imide resin having excellent heat resistance
and melt flowability.
That is, the pre~ent invention provides a process
for producing high molecular weight polyamide-imide resin
having a reduced viscosity of 0.3 dl/g or above by reacting a
trimellitic acid derivative (I~ selected from the group
consisting of trimellitic acid anhydride and an ester of
trimellitic acid or trimellitic acid anhydride with an
alcohol and an aromatic diamine (II), in the presence of a
polar solvent and dehydration catalyst, which process
comprises the two reaction stages: (a) a ~irst reaction
stage which comprises reacting the trimellitic acid
deriYative (I) and the aromatic diamine tII) in the presence
of a polar solvent in the presence of a first dehydration
ca~alyst selected from the group consisting of boric acld,
boric anhydride, phosphoric aoidj pyrophosphoric acids,
metaphosphoric acids, ethylmetaphosphoric acid,
polyphospho~ic acid, phosphorus pentoxide, and phosphoric
pentachloride at a temperature ranging from about 195C to
about 205C until a polyamide-imide resin having a reduced
d~

1 31 5463
viscosity of 0.2 to 0.5 dl/g as measured at a concentration
of 0.5 g/dl in di~ethylformamide at 30C is produced; and ~b)
a second reaction stage which comprises adding a phosphorus
triester as a second dehydration catalyst to the reaction
mixture resulting from the first reaction stage and further
reacting the reaction mixture at a temperature ranging from
about 180C to about 190C until a high molecular weight
polyamide-imide resin having a reduced viscosity of 0.3 dl/g
or above as measured at a concentration of 0.5 g/dl in
dimethylformamide at 30C is produced; the first dehydration
catalyst being used in an amount of 0.5 to 20% by weight on
the basis of the total of the trimellitic acid derivative (I)
and the aromatic diamine (II), and the phosphorus triester as
a second dehydration catalyst being used in an amount of 0.1
to 50% by weight on the basis of the total of the trimellitic
acid derivative (I) and the aromatic diamine (II).
Further, the present invention provides a process
for producing high molecular weight polyamide imide resin
having a reduced viscosity of 0.3 dl/g or above by reacting a
trimellitic acid deri~ative (I) selected from the group
consisting of trimellitic acid anhydride and an ester of
trimellitic acid or trimellitic acid anhydride with an
alcohol and an aromatic diamine (II), and one or more
compounds (III) selected from the group consisting of (A)
dicarboxylic acids and (B) lactams, in the presence of a
polar solvent and dehydration catalyst, which process
comprises the two reaction stages: (a) a first reaction
stage which comprises reacting the trimellitic acid

1315463
derivative (I) and the aromatic diamine (II), and one or more
compounds (III) selected from the group consisting of (A3
dicarboxylic acids and (B) lactams, in the presence of a
polar solvent in the presence of a first dehydration catalyst
selected from the group consisting of boric acid, boric
anhydride, phosphoric acid, pyrophosphoric acids,
metaphosphoric acids, ethylmetaphosphoric acid,
polyphosphoric acid, phosphorus pentoxide, and phosphoric
pentachloride at a temperature ranging from about 195C to
about 205C until a polyamide-imide resin having a reduced
viscosity of 0.2 to 0.5 dl/g as measured at a concentration
of 0.5 g/dl in dimethylformamide at 30C is produced; and (b)
a second reaction stage which comprises adding a phosphorus
triester as a second dehydration catalyst to the reaction
mixture resulting from the first reaction stage and further
reacting the reaction mixture at a temperature ranging from
about ~80C to about 190-C until a high molecular weight
polyamide-imide resin having a reduced viscosity of 0.3 dl/g
or above as measured at a concentration of 0.5 g/dl in
dimethylformamide at 30C is produced; the first dehydration
catalyst being used in an amount of 0~5 to 20% by weight on
the basls of the total of the trimellitic acid derivative (I)
and the aromatic diamine (II), and the one or more compounds
(III) and the phosphorus triester as a second dehydration
catalyst being used in an amount of 0.1 to 50% by weight on
the basis of the total of the trimellitic acid derivative (I)
: the aromatic diamine (II) and the one or more compounds
(III).
.,.~, ~,
~''

1 31 5463
- 6a -
BRIEF DESCRIPTION OF DRAWING
Figure 1 shows the relationship between reaction
time and reduced viscosity in Example 2 and Comparative
Examples 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Some illustrative examples of (I) trimellitic
acid derivatives to be used in the present invention
include trimellitic acid anhydride and esters of
trimellitic acid or trimellitic acid anhydride with an
alcohol. Typical examples of the esters of trimellitic
acid or trimellitic acid anhydride with an alcohol are
monomethylesters o~ trimellitic acid or trimellitic acid
anhydride. The pre~erred trimellitic acid derivative is
trimellitic acid anhydride.
Some illustrative examples o~ (IIj aromatic

~ 131S463
1 diamines to be used in the pre.sent invention include
m-phenylenediamine, p-phenylenediamine,
4,4' -diaminodiphenylpropane, 4,4' -diaminodiphenylmethane,
4,4' -diaminodiphenyl sulfide, 4,4' -diaminodiphenyl
sulfone, 4,4' -diaminodiphenyl ether, 1,5-
diaminonaphthalene,
3,3' -diaminobiphenyl, 3,3' -dimethoxybenzidine,
1,3-diamino-4-isopropylbenzene, xylylenediamine,
4,4~ -diaminoterphenyls, 4,4"' -diaminoquarterphenyl,
1,4-bis(p-aminophenoxy)benzene,
4,4' -bis(p-aminophenoxy)diphenyl sulfone~ ~
4,4' -bis(p-aminophenoxy)biphenyl,
2,2-bis[4-(4-aminophenoxy)phenyl]propane,
2,2-bisl4-(4-aminophenoxy)phenyl~hexafluoropropane,
4,4' -diaminoben~ophenone,
benzidine-2,3,5,6-tetramethyl-p-phenylenediamine,
diaminotoluenes, tetrafluorophenylened1amines, and
diaminooctafluorobiphenyls. These compounds may be used
indlvidually or as a mixture thereof. In consideration o-f
20 ~ heat resistance and economical e~ficiency, the preferred
aromatic diamines are 4~4' -dlaminodiphenylmethane, 4,4' -
diaminodiphenyl ether,~p-phenylenediamine, and m-
phenylenediamine.
The preferred polar solvents to be used in the
present invention are those being capable of easily

1 31 5463
1 dissolving the produced polyamide-imide resins and having a
boiling point o~ 180C or above. Some illustrative
examples o~ the preferred polar solven1;s 1nC1Ude N-
methylpyrrolidone, N-ethylpyrrolidone, N-butylpyrrolidone,
phenol, cresols, xylenols, r -butyrolactone, and sulfolane.
Among these, the particularly pre~erred is N-
methylpyrrolidone.
Some illustrative examples of the first
dehydration catalysts to be used in the present invention
in the first reaction stage include boric acid and boric
acid derivatives such as boric anhydride; pentavalent
phosphorus compounds, for example, phosphoric acid,
pyrophosphorlc acid, metaphosphoric acids such as
trimetaphosphoric acid, ethylmetaphosphorie acid,
polyphosphoric acids such as tetrapolyphosphoric acid,
:
phosphorus pentoxide, and phosphorlc pentachloride. The
preferred are phosphoric acid, polyphosphoric acids, boric
acid, and boric anhydride, and the particularly preferred
ls phosphoric acid.
The second dehydration catalysts to be used in
the present invention in the second re~ction stage are
phosphorous triesters~represented by the formula (R0)3P,
wherein R is an aliphatic or aromatic su~stituent such as
methyl, ethyl, isopropyl, butyl, 2-ethylhexyl, isooctyl,
decyl, lauryl, phenyl, methylphenyl, ethylphenyl,

1315463
1 butylphenyl, octadecylphenyl, nonylphen~l, diphenylnonyl,
biphen~l~l, cyclohexyl, and indenyl; and the preferred is
triphanyl phosphite.
In the present invention, ~I~ trimellitic acid
derivative and (II) arosnatic diamine are used preferably in
an amount equimolar with each other, and the particularly
preferable molar ratio, (II)/~I), is from 0.98 to 1.02.
In the present invention, one or more compounds
(III) selected from the group consisting of (A)
dicarboxylic acids and (B) lactams in addition to the (I)
trimellitic acid derivative and (II) aro~atic diamine
mentioned above may be used as materials at need.
Some illustrative examples of the (A) ~
dicarbo~ylic acids~which may be~used in the present
inverlt10n include succinic aeid, adipic acid, sebacic acid,
dodecanedicarboxylic acid, isophthalic acid, and
terephthalic acid. In consideration of heat resistance and
solubility o-~ the product resins, isophthalic acid is
prefe~ably used.
In case of using the (A) dicarboxylic acids, it
is desirable, in conslderation of heat resistance and
flowability at the time of moldlng process, to use (A) as a
part of acid component in an amount of 0.05 to O.S0 mol,
preferably 0.1 to Q.3 mol per 1 mol of the (II) aromatic
diamine.

1 31 ~463
1 Some illustrative examples of the (B) lactams
which may be used in the present invention include lactams
represented by the following general formu:La:
NH ~ C0
~ ( C:~I2 ) r~/
wherein, n is an integer of from 2 to 20,
and the preferred is ~ -caprolactam.
From the viewpoint of heat resistance and
flowability at the time of molding process. it is desirable
to use (B) in an amount of 0.05 to 0.50 mol, pre~erably
0.05 to 0.30 mol per 1 mol of the (II) aromatic diamine.
According to the present invention, acid
component and amine component are reacted firstly in the
: : ~ first reaction stage using the first dehydration catalyst
until the reduced viscosity of polyamide-imide resin
: produced reaches 0.2 to 0.5 dl/g, and the reaction is
: further progressed by adding a phosphorous triester as the
; 20 second dehydration catalyst to increase the reduced
~iscosity of the polyamide-imide resin to 0.3 dl~g or
above.
If the first reaction stage is concluded before
: the reduced vi,scosity reaches 0.2 dl/g, the amount o~ the
: : 25 second dehydration catalyst required wiIl be approximatelY

~15463
1 equivalent to the amount of acid component or amine
component, causing the sa~e problem as that caused by
separate use of the second dehydration catalyst. If the
reduced viscosity exceeds 0.5 dl/g, partial gelation or
runaway reaction will occur at the time of addition of the
second dehydration catalyst, causing a di-friculty in
controlling the molecular weight. The reduced viscosity of
the polyamide-imide resin obtained in the second reaction
stage should be 0.3 dl/g or above. In consideration of
heat resistance, mechanical strength or the llke, the
preferable reduced viscosity is 0.4 or above.
From the viewpoint of reactivity and facility~of
purification, it is preferable to use the first dehydration
catalyst of the present invention in an amount of 0.5 to 20
% by weight on the basis of total of the reaction species
including (I) and ~II) or~ (I), (II) and (III). The
particularly preferable amount is l to 5 % by weight.
From the view point of reactivity and facility of
reaction control, it is preferable to use the second
dehydration catalyst in an amount of 0.1 to 50 % by weight
on the basis of total of the reaction species including (I)
and (II) or ~I), (II) and (III). The particularly
preferable amount is 3 to 30;X by weight.
In the present invention, the total concentration
of the reactants of the polymerization system during the

1315463
1~
1 first reaction stage using the ~irst dehydration catalyst
is preferably about 50 to 60 % by weight, and that during
the second reaction stage using -the second dehydration
catalyst is preferably about 30 to 40 % by weight. With
regard to the reaction temperature, it is desirable to add
the ~irst dehydration catalyst at a temperature in the
vicinity of 170C , then carry out polymerization at a
temperature in the vicinity o-f 195 to 205C , and conduct
the addition o~ the second dehydration catalyst and the
reaction in the second reaction stage at a temperature
range of about 180 to
190C .
It is desirable to carry out the ~irst reaction
stage and second reaction stage in an atmosphere of an
inert gas such as nitro~en.
The polyamide-imlde resins obtained by the
present invention may be protected with end-group blocking
agents at the end of the polymerization reaction. The end-
group protection increases the heat stability at the time20 o-~ molding.
The end-group blocking agents which may be used
include, ~or example, phthalic anhydride, benzoic acid,
acetic anhydride, aniline, n-butylamine, and phenyl
isocyanate.
Z5 The polyamide-imide resins obtained by the

1 31 5463
13
1 present invention may be, if desired, further diluted by
adding the above-described polar solvents or low boiling
point organic solvents, such as chloroform,
tetrahydrofuran, diox~ne, toluene, and xylene, to the
product solution resulting from the polymerization.
The polyamide-imide resins obtained hy the
present invention may be used in solution state or powder
state and also may be blended with other kinds o~ polymers,
additives, fillers, reinforcing agents, etc., if de.sired.
The polyamide-imide resins obtained by the
present invention, at need, may be improved o-f their
physical properties extremely by heating them (for example,
at 200 to 300~ for 1 to 24 hours) after molding.
According to the present invention, high
molecular weight polyamide-imide resins having excellent
heat resistance, melt flowability, and economical
efficiency can be obtained.
~ :
The polyamlde-imide resins obtained by the
present invention are suitable for the use of thermoplastic
moldlng materials and are~ also useful as, ~or example, heat
resistant materials ~or~heat resistant paints, heat
resistant sheet~, heat resistant adhesives, heat resistant
la~inating materials, heat resistant sliding materials,
heat resistant fibers, heat resistant films, and the like.
In order to more fully and clearly illustrate the
~ '

1315~63
14
1 present invention the following examples are set ~orth. It
is intended that the examples be considered as illustrative
rather than limiting the invention as disclosed and claimed
herein.
The following examples also illustrate processes
falling outside the scope of the instant invention and are
presented for comparative purposes only.
EXAMPLES 1 to 5 and COMPARATIVE EXAMPLES 1 to 5
EX~MPLE 1
Mol ratio g wt. part
trimellitic acid anhydride1.00 192 48.7
4,4' -diaminodiphenylmethane1.02 202 51.3
a~ueous phosphoric acid solution 0.02 2.3 0.5
(content of phosphoric acid: 85 %)
N-methylpyrrolidone - 394 100
triphenyl phosphite 0.13 40 10
: ~ :
Irlto a four necked flask equipped with a stirrer,
a nitrogen introduction tube, and an apparatus for moisture
determination were placed the above components except
triphenyl phosphlte, and the con~ent was dissolved by
raising the temperature slowly to 180C with stirring under
introduction of nitrogen gas. Subsequently, the resulting
~ ,~ ,,

1315463
1 solution was further heated to 210C and reaction was
continued while removing rapidly ~he distilled water out of
the reaction syskem and at the same time filling up the
distilled N-methylpyrrolidone (first reaction stage). The
progress of reaction was watched by measuring~the increase
of molecular weight of the polymer with ~PLC (high
per~ormanee liquid chromatography) to obtain a polyamide-
imide resin having a reduced viscosity o~ U.3 dl~g as
measured at a concentration of 0.5 g/dl in
dimethylformamide at 30C . Subsequently, the resin
concentration was diluted to 35 % by weight by adding N-
`methylpyrrolldone and the reactlon temperature was lowered
to 180C . Triphenyl phosphite was added in 5 portions over
a period of 2 hours and the reactlon was continued (~second~
reaction stage). The end point o* the reaction was
determined by measuring the molecular weight with~HPLC.
: ~ :
Thus a polyamide-imide resin~having a reduced viscosity of
0.65 dl/g was Pinally obtained. Nothlng unusual such as
scorching o-f resin to the inner wall of the flask or
gelation was observed.~
EXAMPLE 2
Mol ratio g wt. part
trimellitic acid anhydride 1.00 192 48.7

1315~63
16
1 4,4' -diaminodiphenylmethane 1.02 202 51.3
aqueous phosphoric acid solution 0Ø223.2 5
(content of phosphoric acid: 85 %)
N-methylpyrrolidone - 394 100
triphenyl phosphite 0.3.2 98.5 25
The procedure of Example 1 was repeated with the
exception that the above components were used. First,
first reaction was carried out to obtain a polyamide-imide
resin having a reduced viscosity of 0.45 dlig.
Subsequently, second reaction was carried out to obtain a
polyamide-imide resin having a -final reduced viscosity of
0.8 dl/g. Nothing unusual such as scorching of resin to
the lnner wall oY the flask or gelation was observed.
. :
15 : EXAMPLE 3
:
Mol ratio g wt. part
trlmellitic acid anhydride 1.00 192 48.7
4,4' -diaminodiphenylmethane 1.02 202 51.3
aqueous phosphoric acid solutlon 0.32 37.l 8
: ~ (content of phosphoric acid: 85 %)
N-methylpyrrolidone - 394 100
: triphenyl phosphite : 0.065 2.0 0.5
The procedure of Exa~mple 1 was repeated with the
~5 exception that the above components were used. F:lrst,

t 31 ~463
1 first reaction was carried out to obtaln a polyamide-imide
resin having a reduced viscosity Or 0.3 dl/g.
Subsequently, second reaction was carried out to obtain
finally a polyamide-imide resin having a reduced viscosity
o-f 0.6 dl~g. Nothing unusual such as scorching o~ resin to
the inner wall of the flask or gelation was observed.
EXAMPLE 4
~ol ratio g wt. part
trimellitic acid anhydride 0.90 172.841.7
4,4' -diaminodiphenylmethane 1.02 202.048.8
isophthalic acid 0.10 16.64.0
~ -caprolactam 0.20 22.65.5
aqueous phosphoric acid solution 0.21 24.3 5.9
(content of phosphoric acid: 85 %)
N-methylpyrrolidone - 414 100
triphenyl phosphite 0.33 103,525
The procedure o~ Example 1 was repeated with the
exception that the above components were used. First,
~irst reaction was carried out to obtain a polyamide-imide
resin having a reduced viscosity of 0.3 dl/g.
Subsequently, second reaction was carried out to obtain a
polyamide-imide resin having a reduced viscos~ty of 0.8
~5 dl/g. Nothing unusual such as scorching of resln to the

13~5~63
18
1 inner wall of the flask or gelation was observed.
EX~MPLE 5
Mol ratio g wt. part
trimellitic acid anhydride 0.85 163.2 ~0.6
4,4' -diaminodiphenylmethane 1.02 202.0 50.3
isophthalic acid 0.15 24.9 6.2
~ -caprolactam 0.10 11.3 2.8
aqueous phosphoric acid solution 0.024 2.4 0.
: (content of phosphoric acid: 85 ~
N-methylpyrrolidone - 401.4 100
triphenyl phosphite 0.52 1~0.5 40
The procedure of Example 1 was repeated with the
~: 15 exception that the above component~ were used. First,
first reaction was carried out to obtain a polyamide-imide
: resin having a reduced viscosity of 0.45 dl/g.
Subsequently, second reaction was carried out to obtain a
polyamide i~ide resin having a final reduced viscosity of
1.0 dl/g. Nothing unusual such as scorching of resin to
the inner wall of the flask or gelation was ob~erved.
: ~ :
:

131~4~3
1 COMPARATIVE EXAMPLE 1
Mol ratio g wt. part
trimellitic acid anhydride l.Q~ 19~ 48.7
4,4' -diaminodiphenylmethane 1.02 202 51.3
N-methylpyrrolidone - 394 100
Into the same type four-necked ~lask as that used
in Example 1 were placed the above components and the
content was dissolved by raising the temperature slowly to
180C with stirring under introductlon of nitrogen gas.
Subsequently, the resulting solution was ~urther heated to
210C and reaction was progressed, while the distilled~
water was rapidly removed o~ out of the reaction system
; 15 and at the same time the distilled N-~ethylpyrrolidone was
filled op (first react~on stage). The progress of reaction
was monitered by measuring the increase of molecular weight
with HPLC to obtain a polyamide-imide resin having a
~ reduced viacoslty of 0.18 dl/g as measured at a
; ~20 concentration of~ 0.5~ g/dl in dlmethylformamide at 30C .
~ ~ The reac~ion product was a low viscoslty liquid.
:~: : :

1315~63
1 COMPARATIVE EXAMPLE 2
Mol ratio g wt. part
trimellitic acid anhydride 1.00 192 48.7
4 ? 4' -diaminodlphenylmethane1.02 202 51.3
N-methylpyrrolidone - 394 100
aqueous phosphorlc acld solution 0.60 69.5 15
(content o~ phosphoric acid: 85 %)
The procedure o~ the reaction stage 1 o~ Example
1 was repeated with the exception that the above components
: were used, to obtain a polyamide-imide resin having a
reduced v~scosity o~ 0.45 dl/g. However, since a:high
temperature and a long reaction tlme (210C - 25 hours)
were required -~or the reaction, scorchlng occurred on the
bottom of the ~lask.~ :
COMPARATIVE EXAMPLE 3
Mol ratio g :wt. part
20~ trimellitic acld anhydride: 1.00 192 48.7
4,4' -diaminodiphenylmethane 1.02 202 51.3
N-methylpyrrolidone - 394 100
triphenyl phosphite 0.76 236 59.9
The procedure o~ the ~irst reaction stage o~

1 31 5463
21
1 Example 1 was repeated with the exceptlon that the above
components were used, to obtain a polyamide-imide resin
having a reduced viscosity o-~ 0.18 dl/g. Subsequently, the
resin concentration was decreased to 3~ % by wei~ht by
adding N-methylpyrrolldone, and th~ reaction temperature
was lowered to 180 to 190C . While the reaction was
progressed by adding triphenyl phosphite in 5 portions over
a period o~ 2 hours, the viscosity o~ varnish was rapidly
increased and gelatinized.
COMPARATIVE EXAMPLE 4
Mol ratio g wt. part
trimellitic acid anhydride 1.00 19248.7
4,4' -diaminodiphenylmethane 1.02 202 51.3
I
N-methylpyrrolldone - 394 100
aqueous phosphoric acid solution 0.02 0.23 0.06
(content of phosphoric acid: 85 %)
triphenyl phosphite 0.76 236 60
The procedure of Example l was repeated with the
exception that the above components were used. First,
first reaction stage was carrled out to obtaln a polyamide-
imide having ~ reduced viscosity of 0.18 dl/g.
Subsequently, triphenyl phosphite was added and reactlon
was progressed ~or about 30 mlnu~es (second reaction
.
.

1315463
22
1 stage). The reduced viscosity o-~ vanish was increased and
the varnish was gelatinized at the end.
COMPARATIVE EXAMPLE 5
Mol ratio g wt. part
trimellitic acid anhydridel.OO 192 4~.7
4,4' -dLaminodiphenylmethane1.02 202 51.3
N-methylpyrrolidone - 394 100
aqueous phosphoric acid solution 0.60 69.6 15
(content o~ phosphoric acid: 85 %)
triphenyl phosphite 0.0064 1.97 0.05
The procedure of Example 1 was repeated w1th the~
exception that the above componente were used. First,
I
1 15 first reaction stage was carrled out to obtain a polyamide-
: .
imide resin having a reduced viscos1ty of 0.35 dl/g.
Subsequently, the second stage polymerization was
attempted. However, polymerization to a high molecular
w~eight polyamide-imide -~ailed to proceed under the reaction
~; 20 condltions, resulting in a solution with a final redueed
ylscoslty o-~ 0.38 dl/~.
~ Films were produced from the polyamide-imide
-~ resins obtained ln E~amples 1 to 5 and Co~parative E~amples
1 to 5 and glass transition tem~erature was mea ured with a
thermomechanical analyzer. The results and the appearance

1315463
23
of reaction in the course o-f synthesis were shown in Table
1.
:: :
:
~: 20
:: ` :
:
~: 2 5

1 3 1 5463
24
u~ c~ o I I L/~ ~ o o
o o o ~ o C~ C~ O C~,
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~ o C:~ o I I o ~o oo I o ~ I
X Z ~ ~1 0 O O
~ o o I I I ~o ~ I o .~ I
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E C`l C`:l O I I Ln I I Ln LE~
c~ o o ~ I I ~r C~ X C~l
._ ~ O ~
C`~ O I I O I I CO ~ 0
2: o o o cY:)OO a)
Ll~ ~0 ~ ~ ~ O ~ O C~ O U~
O ~ O o o o O ~ C~l
O a~ C~ CO ~3 0 Ct~
:Z: ~ O O O O O C`~
Q~ C.~ O I I 00 u~ h~ CD ~ O
E Z .~ O O O C`~
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r ~ ~ ~1) h c~
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E ~ _ O ~ -- ~ O ~ E ~:
.~ al h h :~ ~: h . ~
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et' ~4 0 1 0 ~-- ~ ta c: Il) ._ ~
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o e ~ $ a~ c~ ~
!S~b
;

t315~63
1 The relationships between reaction time and
reduced viscosity in Example 2 and Comparative Examples 1
and 2 are shown in Fi~ure 1.
The reaction appearance shown in the Table 1 was
~udged by examinlng the occurrence of scorching on the
flaskls wall or generation o~ gelatinized matter. O
represents absence, and x represents presence.
~ he measuremen-t o~ glass transition temperatures
(Tg) of films were conducted using a thermomechanical
analyY,er of Perkin Elmer TMS-1.
Measuring conditions
tension method
temperature raising rate: 10C /min, load: 5 g,
sample: 2 mm width, spun: 10 ~n
Production o~ ~ilm
25 wt.% varnish was applied over a clean glass
plate with an applicator to a thlckness o~ 80 ~ m and was
2~ then heated for 30 minutes with a 250C hot air dryer to
obtain a film of about 20 ~ m thlckness.