COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952-69 COMPLETE SPECIFICATION
(ORIGINAL)
Class Ir Application Number: Lodged: SForm nt. Class Complete Specification Lodged: Accepted: Published: Priority Related Art NIme of Applicant HOECHST AKTIENGESELLSCHAFT Address of Applicant :50 Bruningstrasse, D-6230 Frankfurt/Main 80, Federal Republic of Germany Actual nventor: MICHAEL HAUBS, OTTO HERRMANN-SCHONHERR 000 00 Address for Service WATERMARK PATENT TRADEMARK ATTORNEYS.
-l0 TT 00 0.
290 Burwood Road, Hawthorn, Victoria, Australia Complete Specification for the invention entitled: HOMOGENEOUSLY MIXED ALLOYS COMPRISING AROMATIC POLYAMIDES AND POLY-N- VINYLPYRROLIDONE, PROCESS FOR THEIR PREPARATION, AND THEIR USE The following statement is a full description of this invention, in luding the best method of performing it known to:- HOECHST AKTIENGESELLSCHAFT HOE 89/F 038 Dr.K/St Description Homogeneously mixed alloys comprising aromatic polyamides and poly-N-vinylpyrrolidone, process for their preparation, and their use The invention relates to homogeneously mixed alloys comprising aromatic polyamides and poly-N-vinylpyrrolidone, a process for their preparation, and their use as molded articles, such as films, coatings or pressings.
The term "homogeneously mixed alloys" inidicates that the components of the alloy are homogeneously mixed with one another.
Aromatic polyamides (referred to as polyaramids below) are known for their excellent thermal, chemical and mechanical properties. Therefore, for example, fibers and films made from raw materialF of this type are highly suitable for industrial areas'of application in particular for reinforcing plastics or as filter materials.
Poly-N-vinylpyrrolidone (PVP) is commercially available in various molecular weights. Up to molecular weights of about one million, PVP is soluble even in cold water.
Softening point (glass transition temperature) of PVP in the fully anhydrous sZate is 175"C. PVP has the following recurring structural units: -E CH2 H The synthesis and properties of PVP are described in detail in Houben-Weyl: Methoden der Organischen Chemie [Methods of Organic Chemistry], Volume XIV/1, pp. 1106 ff. (1961).
~-L
2 The production of microporous, high tenacity hollow fibers from a stable solution of aromatic polysulfone 'i polymers or aromatic polyamides as fiber-forming polyi mers, PVP and suitable solvents, such as dimethylaceta- I; 5 mide or dimethylformamide, is known (US Patent 4,051,300). This publication states that the polyaramid is only compatible with PVP to a limited extent and that phase separation occurs during the coagulation process described.
It is furthermore known to alloy polymers in order to prepare novel materials which can only be achieved with difficulty, or not at all, in other ways, for example by copolymerization. In particular, technologically important properties, for example thermal stability, mechanical properties and solvent resistance, can be improved in this way, and in addition their economic efficiency is increased.
However, the prediction of the properties of an alloy from the properties of the individual components is far away, even today. The alloying of polymers therefore S..still remains substantially empirical. In particluar, the homogeneous miscibility or compatibility of alloys, specifically those comprising polymers with a strong interaction, can hitherto not be predicted in spite of a very large number of experimental and theoretical papers in this area. Thus, it is known that compatible alloys of polymers are rare (Journal of Polymer Science, Polymer Physics Edition, Vol. 21, p. 11 (1983)).
Elsewhere, it is stated that research activities have resulted in the discovery of a number of miscible polymer combinations, and that complete miscibility is an unusual property in binary polymer mixtures, which normally tend to form two-phase systems (Polymer, Vol. 24, p. (1983)).
It is also known that a considerable majority of pairs of 3 polymers form two-phase blends after mixing, as can be presumed on the basis of the low mixing entropy for very large molecules. These mixtures are generally characterized by opacity, different thermal transitions and poor mechanical properties (Olabisi, Robeson, Shaw: Polymer-Polymer Miscibility, Academic Press, New York, p.
7 (1979)).
In another publication, it is stated that the number of blend systems known to be miscible has increased significantly in the last decade. In addition, a number of systems have been found which have an upper or lower critical solution temperature, i.e. complete miscibility only exists in a limited temperature range. Modern thermodynamic theories have hitherto only been successful to a limited extent as far as the predictability of oo miscibility is concerned. It was therefore doubted whether any practical theories can be developed which take into account the real complexities imparted on the polymer-polymer interactions by nature (Macromolecules, Vol. 16, p. 753 (1983)).
Alloys of homogeneously mixed polymers are thus very rare. In addition, miscibility cannot be predicted. On the other hand, the methods for experimental determination of the miscibility behavior are known (Olabisi, Robeson, Shawt Polymer-Polymer-Miscibility, Academic oo o Press, New York, pp. 321-327 (1979)).
The following are some of the differentiating features: The clearest criterion for homogeneous miscibility is the appearance of a single glass transition temperature between those of the components used to prepare the mixture.
The transparency of films of polymer alloys is an indication that the components are homogeneously mixed.
r,
I
4 Multiphase alloys can usually be differentiated from homogeneously mixed alloys by means of transmission electron microscopic studies of thin sections.
Scanning electron microscopic studies of fracture surfaces or etched surfaces of alloys allow conclusions to be made on the miscibility of the components present.
In industry, there is great interest in homogeneously mixed polymer alloys, since their properties can be matched in a specific way to certain demands by varying the components and the mixing ratios. Due to their exceptional thermal and mechanical properties, polyamides are particularly important as an alloy component. For certain applications, for example to improve the processibility, a reduction in the glass transition temperature is advantageous. The adaptation of mechanical properties in a targeted manner is required in practice. Finally, it is important for many applications to achieve a certain water-absorption capacity. Since the alloys known hither- 1 20 to are usually not up to these requirements, the object was thus to find novel polyaramid alloys whose components are homogeneously mixed and which satisfy the criteria mentioned.
The object has been achieved in that certain polyaramids 25 form surprisingly homogeneously mixed alloys with PVP which, irrespective of the mixing ratio of the two components, allow the abovementioned physical properties to be set in a targeted manner.
The invention relates to a homogeneously mixed alloy substantially containing A) poly-N-vinylpyrrolidone and B) at least one homo- or copolyaramid containing at least one recurring structural unit of the formula (I) o o IS 1 I1 (I)
E
1 C E 2
(I
5 in which El and E 2 are identical or different and are selected from the groups
CH
3 CH 3 0 0
CH
3
NH-CO-&
Ar 1 or Ar-X-Ar2-, o 5 in which Ar 1 and Ar 2 are identical or different 1,2-phenylene, 1,3-phenylene or 1,4-phenylene radicals which may be substituted by (Ci-C)-alkyl, (C,-C 6 )-alkoxy, each preferably having up to 4 carbon atoms in the alkyl S group, -CF 3 or halogen, for example fluorine, chlorine or 10 bromine, and the radical X a) is a direct bond or one of the following divalent radicals
-SO
2 in which R 1 is hydrogen, (C-C)-alkyl or fluoroalkyl having 1-4 carbon atoms o 15 in the alkyl group, such as -C(CH 3 2 or-
C(CF
3 or b) -Z-Ar l in which Z is the radical or
-C(CH
3 2 or c) -O-Ar'-Y-Ar2-O-, in which Y is as defined under Xa).
The following compounds are suitable, for example, for the preparation of the polyaramids having the recurring structural units of the formula and required according to the invention: Aromatic dicarboxylic acid derivatives of the formula C1-CO-Arl-CO-C1, such as 4,4'-diphenylsulfone dicarboxylic acid dichloride, 4,4'-diphenyl ether dicarboxylic acid dichloride, 4,4'-diphenyldicarboxylic acid dichloride, 6 2,6-naphthalenedicarboxylic acid dichloride, isophthalic acid dichloride, but very particularly terephthalic acid dichloride and substituted terephthalic acid dichloride, for example 2-chloroterephthalic acid dichloride, aromatic diamines of the structure H 2 N-Ar'-NH,, such as m-phenylenediamines or substituted phenylenediamines, for example 2-chloro-, 2,5-dichloro- or 2-methoxy-p-phenylenediamine, in particular p-phenylenediamine, substituted benzidine derivatives of the formula R2 R2
H
2 N NH2 in which R 2 is a lower alkyl or alkoxy radical, in each case having up to 4 carbon atoms in the alkyl group, preferably -CH 3 or -OCH 3 or is-F, Cl or Br, such as 3,3'-dimethoxy-, 3,3'-dichloro-, 2,2'-dimethyland, preferably, 3,3'-dimethylbenzidine, a diamine components of the formula H 2 N-ATr 1 -X-Ar 2
-NH
2 such as 4,4'-diaminobenzophenone, bis[4-aminophenyl] I sulfone, bis[4-(4'-aminophenoxy)phenyl] sulfone, 1,2-bis[4'-aminophenoxy]benzene, 1,4-bis[(4'-aminophenyl)isopropyl]benzene, 2,2'-bis[4-(4'-aminophenoxy)phenyl]propane, in particular 1,4-bis(4'-aminophenoxy)benzene.
It is likewise possible to employ mixtures of the dicarboxylic acid chlorides mentioned and/or of the diamines.
The homo- or copolyaramid is formed from recurring structural units of the formula The individual structural units of the polymersI may be different, so that El and E 2 may be different radicals in the copolymers.
7 El is preferably a 1,3- or 1,4-phenylene radical, the radical
CH
3 H 3 C CH 3 CH3 or 0- 3 0
CH
3 CH 3 and E 2 is preferably a 1,4-phenylene radical or the radical R2 R2 in which R 2 is a lower alkyl or alkoxy radical, in each case having up to 4 carbon atoms in the alkyl group, or o I is F, Cl or Br, or the radical 0. 0 where X' is the group -C(R 1 2 in which R 1 is hydrogen or 10 (Ci-C 4 )-alkyl, or the group -0 -0i An alloy which, besides PVP, contains at least one copolyaramid having at least three randomly recurring structural units of the formula in which o0 o E 1 is a divalent p-phenylene radical,
E
2 in the three recurring structural units is once each a Yw divalent p-phenylene radical, a radical of the formula R2 R2 where R 2 is CH 3
OCH
3 F, Cl or Br, and a radical of the formula 8 in which X' is as defined above, in particular where the copolyaramid contains the recurring structural units +CO- 0 -CO-NH- -NH-
CH
3
CH
3 CO-- -CO-NH and -4{CO CO-NH 0 0 O- NH-- Copolyaramids of this composition are known from EP-A 0,199,090, to which reference is hereby made.
Polyaramids can generally be prepared in a known manner by solution, interface or melt condensation. The way in which the polycondensation is carried out determines here whether random copolymers, block or graft copolymers are produced.
Solution condensation of the aromatic dicarboxylic acid dichlorides with the aromatic diamines is carried out in aprbtic, polar solvents of the amide type, such as N,N-dimethylacetamide or, in particular, N-methyl-2pyrrolidone. If necessary, halide salts from group one and/or two of the Periodic Table can be added to these solvents in a known manner in order to inc:rease the solvating power or to stabilize the polyamide solutions.
Preferred additives are calcium chloride and/or lithium chloride. The amount of dicarboxylic acid dichloride is selected so that the desired solution viscosity is achieved.
The polycondensation temperatures are usually between and +120°C, preferably between +10 and +100 0
C.
Particularly good results are achieved at reaction temperatures between +10 and +80 0 C. Polycondensation reactions are generally carried out so that, when the 9 reaction is complete, 2 to 30, preferably 3.5 to 20, by weight of polycondensate is present in the solution.
The polycondensation can be terminated in a customary manner, for example by adding monofunctional compounds, such as benzoyl chloride.
When the polycondensation is complete, i.e. when the polymer solution has reached the viscosity necessary for further processing, the hydrogen chloride produced, which is loosely bound to the amide solvent, is neutralized by adding basic substances. Examples of substances which are suitable for this purpose are lithium hydroxide, calcium Shydroxide, but in particular calcium oxide.
The alloys according to the invention can generally be prepared in a customary manner from a common solution of PVP and a polyaramid in an aprotic organic solvent, for example dimethylformamide, dimethyl sulfoxide, N-methylpyrrolidone or N,N-dimethylacetamide. The following possibilities, for example, are available for this purpose: 1. a) Polycondensation of a polyaramid by solution, interface or melt condensation, Sb) dissolution of the resultant polyaramid, c) dissolution of PVP and d) subsequent mixing of the PVP solution with the polyaramid solution.
2. a) Solution condensation of a polyaramid and b) subsequent direct admixing of dry PVP or a PVP solution directly into the polycondensation batch.
3. a) Solution condensation of a polyaramid in the presence of PVP.
This method also gives homogeneous mixtures of .the components. To this end, the diamines are _i_ 10 dissolved together with PVP and condensed by addition of dicarboxylic acid dichlorides to form a PVP/polyaramid solution.
The alloys can be isolated by removing the solvent, preferably by evaporation, or t, \VP/polyaramid solutions obtained are processed further in a known manner to give shaped structures, such as films or pressings. The alloys have a very wide variety of uses since the components mix homogeneously.
The molecular weight of the PVP, given as the weight oo average, is generally 1,000 3,000,000, preferably o O 40,000 to 200,000, in particular 50,000 to 100,000.
OC
o The components of the alloys according to the invention ao are homogeneously miscible in all ratios. In particular, 000 Sooo 15 the alloys contain PVP in amounts of from 2 to 98% by weight, preferably 15 to 85% by weight, and particularly preferably 30 to 70% by weight, relative to the sum of components (A B).
00L 0 oo .The alloys may contain additives in customary amounts, for example thermal stabilizers or UV stabilizers.
o Reinforcing fibers can also generally be added in amounts of up to 50% by weight, for example carbon fibers, aramid fibers or glass fibers, also in the form of woven °o oo fabrics. In addition, further polymers, for example polyimides or polyesters, may be added, for example in amounts of up to 10% by weight. The amount ratios in both cases always relate to the sum of components (A B).
Depending on the PVP content, the glass transition temperature of the alloys according to the invention may be varied in a targeted manner. In the same way, the water-absorption capacity of the alloys can be influenced. The dyeability of aramids can be achieved, for example, by admixing a colored PVP copolymer. Finally, the use of the alloys according to the invention is more 11 economic than aramids.
The homogeneous miscibility of the components of the alloys was proven using several of the above-described methods. For example, homogeneous alloys which contain a polyaramid with a glass transition temperature below decomposition temperature which can be detected by differential calorimetry exhibit a single glass transition temperature, determined by differential calorimetry, between that of PVP (175C) and that of the polyaramid employed. In addition, it is entirely surprising that the water-soluble PVP is not dissolved out of the alloys according to the invention by water, even by boiling for 'o several hours. This is a further indication of the presence of an alloy comprising homogeneously mixed components.
SExamples 1) 0.4 mol of 2,2'-bis[4-(4'-aminophenoxy)phenyl]propane was dissolved under nitrogen in 2,000 g of N-methylpyrrolidone (NMP), and 0.4 mol of °o °20 phthalic acid dichloride was added between 15 0 C and 70 0
C
over the course of 60 minutes.
The clear solution was stirred for about 40 minutes at 0 C and subsequently neutralized with 24.5 g of CaO (96% purity, i.e. in excess, corresponding to 0.42 mol) and stirred for a further 30 minutes at The solution was filtered and coagulated in water. The precipitated polyaramid was washed several times with water and then with acetone. The polymer was dried at 130°C under reduced pressure to constant weight.
According to DSC measurements, the polyaramid obtained has a glass transition temperature Tg of 255°C.
12 2) 5 g of poly-N-vinylpyrrolidone (PVP) were dissolved in about 90 g of N-methylpyrrolidone at room temperature together with 5 g of the polyaramid described in Example 1. The mixture was subsequently freed from solvent at 110'C under reduced pressure to constant weight. The resultant PVP/polyaramid alloy exhibits, according to DSC measurements, a single glass transition temperature of 225°C, and was therefore classified as homogeneously mixed.
3) A polyaramid was prepared in accordance with Example 1 using 0.4 mol of the diamine from Example 1 and 0.4 mol of terephthalic acid dichloride (TPC). Tg 235*C.
The polyaramid obtained was used to prepare PVP alloys of different PVP content in accordance with Example 2.
Each of the mixtures obtained exhibits, according to DSC measurements, a single glass- transition temperature dependent on the composition, and was therefore classified as homogeneously mixed (see figure and table below).
PVP content in by weight 0 25 50 75 100 Glass transition temperature in °C 235 228 217 200 175 4) 4 g of an alloy described in Example 3, comprising of PVP and 50% of polyaramid, were ground in a mill and subsequently pressed at 250"C under a pressure of 0.2 t. This gave a transparent plate which did not scatter visible light.
15 g of PVP and 15 g of the polyaramid described in Example 3 ;were dissolved together in 170 g of N-methylpyrrolidone at room temperature, and the solution was LL, I 13 degassed and cast to form films. To this end, the mixed solution was spread on glass plates at 60 0 C using a doctor blade. The cast films were subsequently pre-dried at 90"C for 48 hours and then freed from solvent under reduced pressure at 110 0 C to constant weight. The film thicknesses were between 2 and 100 Am, depending on the layer thicknesses applied.
The films are mechanically stable, non-brittle, colorless and transparent. They exhibit a water absorption of 9.8% measured at 23"C and 85% relative humidity. Films treated with boiling water for about 120 minutes exhibit a single glass transition temperature of 217"C which agrees with S°the glass transition temperature of the untreated films.
00o S 6) 0.2 mol of p-phenylenediamine, 0.2 mol of 1,4bis(4'-aminophenoxy)benzene and 0.4 mol of 3,3'-dimethylo. benzidine were dissolved together in 3.750 g of N-methylpyrrolidone. 0.8 mol of terephthalic acid dichloride was added in one portion at 16"C, and the mixture was heated to 60"C with stirring over the course of about 20 minutes. The clear solution was neutralized using 49 g of CaO and subsequently stirred for about a further minutes at 70"C, and 268.8 g of dried PVP were added with stirring. The mixed solution was filtered and processed to films in accordance with Example The films obtained are transparent, colorless and mechanically stable. According to DSC measurements, they, like the aramid employed do not exhibit a glass transition temperature of below 400 0
C.
Both fracture surfaces of films fractured in liquid nitrogen and surfaces etched with various solvents (for example water or methylene chloride) or oxygen were examined by scanning electron microscopy. All the photographs exhibit smooth fracture surfaces or surfaces.
Besides the scanning electron microscopic studies, 14 transmission electron microscopic studies were also carried out both of thin sections and of thin sections of the films contrasted with iodine. None of the transmission electron microscopic pictures exhibited any inhomogeneity of the films.
The experimental results described show that the components of the alloys are homogeneously mixed.
7) (Polycondensation in the presence of PVP) 89.7 g of dried PVP were dissolved in 734 g of distilled NMP. A 10 solution of 10.8 g of p-phenylenediamine, 42.5 g of 3,3'o oo o° dimethylbenzidine and 29.2 g of 1,4-bis(4'-aminophenoxy)o benzene in 1,000 g of distilled NMP was added and the mixture was cooled to 15 0
C.
oi oo o .o 0 15 0oo 20 0 o 0 L
Q
78.8 g of terephthalic acid dichloride (TPC) were added to this solution in one portion with stirring. Due to the heat of reaction, the temperature increased to about 23"C. The viscous solution was warmed to 50 0 C, and sufficient further TPC was added until the desired viscosity had been reached. 2.4 g of benzoyl chloride were then added to convert the remaining amino end groups. The mixture was stirred for about a further 1/2 hour, and the hydrogen chloride loosely bound to NMP was then neutralized by adding 24.5 g of calcium oxide. After filtration, the viscous solution is directly suitable for the preparation of films, coatings and the like.
o a o o o o "25 1! 8) 14) In the individual examples in the table below, the starting materials are listed for the polyaramids, furthermore the amounts employed and the glass transition temperatures Tg obtained. The polyaramids were prepared as in Example 1, and the alloys were prepared in corresponding manner to Example 2 (in all cases the PVP:polyaramid weight ratio is 50:50) and the film was produced as in Example 14 (ratio 50:50).
Li
TABLE
Moles DJ ac 0 0 0 0 0 000 0
C'
0
C
Mo les Ex. Diamine Lcarboxylfc C ~id chloride Tg Molding* 8 2,2'-BiB[4-(4'-aminophenoxy) phenyl 3propane 9 BiB[4-(4'-aminophenoxy)phenyl] sulf one 1,2-BiB[4'-aminophenoxy]benzene 11 2,2'-Bis[4-(4'-aminophenoxy) phenyl 3propane 1, 4-Bis -aminophenylisopropyl ]benzene 12 2,2'-BiB[4-(4'-aminophenoxy) phenyl 3propane 0.4 0.4 0.4 0.2 0.2 0.4
H
3 C CH~ 3
TDC*
0.4 265vOC 280'C 110, 0
C
230 0
C
210 0 C 0.4 0.4 TDC A 150 0
C
TDC
TDC
0.4 0.2 0.2 265 0
C
245 0
C
2200C 220 0
C
phthalic acid dichloride 13 2,2'-Bis[4-(4'-aminophenoxy) phenyl ]propane Bis [4-aminophenyl] sulf one 14 2,2'-Bis[4-(4'-aminophenoxy)phenyl ]propane 1, 4-Bis -aminophenoxy 1benzene 0.2 0.2 0.2 0.2 TDC 0.4 0.4 2950C 260 0
C
2300C 215 0 C TDC
TDC
F
A terephthlic acid film alloy dichloride 16 Comparison example g of PVP were dissolved at room temperature in 90 g of NMP with 5 g of a polyether imide (R)Ultem 1000 (manufacturer General Electric Co., Schenectady USA) (Tg 217 0 and the solvent was subsequently removed by evaporation under reduced pressure. The alloy exhibits the two glass transition temperatures of the starting materials of 175 0 C and 217"C and is accordingly not homogeneously mixed.
a c 0 5~1