DE2208811C2 - Aromatic polyamides - Google Patents

Description

H ₂ N

NH ₃

NH,

NH,

or

H ₃ N

NH ₂

in Ν, Ν'-dimethylacetamide or N-methylpyrrolidone using the chlorides or bromides of the alkali or alkaline earth metals as Solubilizer.

aromatic diamines that have one or two quinazolone rings contained in the molecule.

Aromatic polyamides made from aromatic diamines of the N-2-phenylbenzotriazole series, inter alia. from N-2- (3-aminophenyl) -5-aminobenzotriazole, and from aromatic dicarboxylic acids, i.a. Terephthalic acid or 2,6-naphthalenedicarboxylic acid, are known from DE-OS 17 20 650 and GB-PS 12 09 353

In DE-OS 19 41932, among other things, an aromatic Called polyamide, the diamine component of which is 2- (3-aminophenyl) -5-aminobenzimidazo! and its dicarboxylic acid component is composed of a mixture of isophthalic acid with terephthalic acid in a molar ratio of 70 to 30

Among those in Vysokomol. Soedin, Ser. A 1970, 12 (10), 2205-2210, named aromatic polyamides, there is also the polyamide from 2- (4-aminophenyl) -5-aminobenzimidazole and terephthalic acid.

These aromatic polyamides are usually obtained by the polycondensation method at low Temperature established. An aromatic diamine is used in a polar organic solvent, like Ν, Ν'-dimethylacetamide or N-methylpyrrolidone, reacted with the dichloride of an aromatic dicarboxylic acid. To improve the solubility of the Aromatic polyamides formed are optionally added to the polar organic solvent so-called solubilizers, e.g. B. chlorides or bromides of the alkali or alkaline earth metals added.

The invention is based on the object of providing such aromatic polyamides from which Fibers with higher strength can be obtained.

The solution to this problem is the aromatic polyamides according to the invention with specific viscosities (determined in 96% H ₂ SO ₄ at 20 ^° C. and a concentration of the polyamide of 0.5 g / 100 ml solvent) between 2 and 20, obtained by the polycondensation of 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid dichloride with

Aromatic polyamides made from diamines, in which the amino groups are attached to an aromatic radical or to interconnected aromatic radicals are directly bonded, and from dicarboxylic acids in which the Carboxyl groups on an aromatic radical or on aromatic radicals connected to one another directly are bound are already known.

Thus, in AT-PS 2 79 168 aromatic polyamides are made from 1,1-bis- (4-aminophenyl) -l-phenylalkanes and aromatic dicarboxylic acids.

Aromatic polyamides, their diamine and / or dicarboxylic acid component 5- or 6-membered heterocyclic Contains rings are also already known.

In those described in US-PS 34 84 407, GB-PS 11 04 411, FR-PS 14 30480 and FR-PS 15 66 254 aromatic polyamides, including from 2,2'-bis (p-aminophenyl) -5,5'-dibenzimidazole, 2,2'-bis (p-aminophenyl) -5,5'-dibenzothiazole or 2,2'-bis (p-aminophenyl) -5,5'-dibenzoxazole and aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6- or 2,7-naphthalenedicarboxylic acid, the component which contains the 5- or 6-membered heterocyclic rings must be symmetrical be.

The aromatic polyamides described in DE-OS 18 11 411 have such H ₂ N as a diamine component

NH,

NH,

NH,

H ₁ N

NH,

in Ν, Ν'-dimethylacetamide or N-methylpyrrolidone with the use of the chlorides or bromides of Alkali or alkaline earth metals as solubilizers.

22 08 8Ί1

In the production of the aromatic polyamides according to the invention, the diamine is Ν, Ν'-dimethylacetamide or N-methylpyrrolidone with the addition of Chlorides or bromides of the alkali or alkaline earth metals dissolved and the solution in small portions a equimolar amount of the dry 2,5-, 2,6- or 2,7-naphthalenedicarboxylic acid dichloride added Solution is stirred continuously. To precipitate the polyamide, the viscous solution is in a poured large excess of water. The polyamide precipitates until the negative reaction washed out for halide ions and dried

The amount of Ν, Ν'-dimethylacetamide or N-methylpyrrolidone is chosen so that the concentration of the polyamide forming in the solution is 5 to 25% (preferably 5 to 12%)

As evidenced by the comparison with threads, threads made from the aromatic polyamides according to the invention from known aromatic polyamides of similar constitution (Vysokomol. Soedin., Ser. A 1970, 12 (10), 2205-2210; DE-OS 17 20 650) suddenly and unpredictably improved properties, such as tensile strength and preservation of the tensile strength wedge after thermal stress. The strength of the threads from the invention aromatic polyamides is also greater than the strength of the threads from the aromatic Polyamides described in AT-PS 2 79 168, US-PS 34 84 407, GB-PS 1104 411, FR-PS 14 30 480, FR-PS 15 66 254, DE-OS 18 11411 and DE-OS 19 41932 described have been.

The molecular weight of the aromatic polyamides according to the invention can be within a wide range set depending on the polycondensation conditions (temperature, stirring, concentration of the solution, etc.).

The aromatic polyamides according to the invention are readily soluble in polar solvents and have properties a homogeneous crystalline structure. They are capable of high-strength heat-resistant fibers and films with high Form modulus of elasticity.

example 1

In a four-necked flask equipped with a stirrer, metering device and tubes for supply and discharge of dry nitrogen, 0.82 g (0.0084 mol) of diamine of the following formula is introduced

H ₇ N

NH,

amide, which contains 5% LiCl, and diluted in the course of Stirred for 2 hours. The specific viscosity of the polyamide is equal to 5.2.

B e i s ρ i e J 3

The procedure is as in Example 2, with the exception that the diamine as the diamine component the following formula is used:

The diamine is dissolved in 15 ml of dried N, N'-dimethylacetamide, containing 5% LiCl, dissolved. In the solution be at room temperature and below Stir within half an hour 0.86 g of 2,6-naphthalenedicarboxylic acid dichloride registered. The solution is stirred for a further two hours, after which the viscous mass with a large excess of Water is precipitated; the precipitate is washed out until the negative reaction to chloride ions and dried at higher temperature. The specific viscosity of the polyamide (η sp.), Determined on a 0.5% solution in sulfuric acid at 20 ° C is the same 3.6. Fibers are made from this polyamide.

Example 2

The procedure is as in Example 1, but after the introduction of the dry acid dichloride, the solution is added up to a 5% concentration with N.N'-dimethylacet-H ₂ N

NH ₂

The polycondensation is carried out by gradually lowering the temperature from 40 ° to 20 ° C. The solution is diluted with 15 ml of N, N'-dimethylacetamide which contains 5% LiCl. The specific

2 (1 viscosity of the polyamide obtained is equal to 20. The polyamide has a high heat resistance, which is apparent from the findings of the thermogravimetry. Thus, the weight loss is, for example, at 300 ⁰ C (Erwärmungrgeschwindigkeit 9 ° C / min) 2%, wherein

r. 400 C <% and at 500 ° C 9%.

Example 4

The synthesis of the polyamide based on the diamine of the formula

NH ₂

H ₇ N

and 2,7-naphthalenedicarboxylic acid dichloride is analogous Example 1 carried out. The solvent used is N-methylpyrrolidone with the addition of 5% LiCl. The specific viscosity of the polyamide, determined on a 0.5% solution in sulfuric acid, is at 20 ° C equal to 4.7. Fibers and films with a strength of 12 to 14 g / denier are obtained from the polyamide.

Example 5

The synthesis of the polyamide takes place under conditions which correspond to those in Example 4, with the exception that 2,6-naphthalenedicarboxylic acid dichloride is used as the acid dichloride component.

The specific viscosity of the polyamide, determined on a 0.5% solution in sulfuric acid at 20 ^° C., is equal to 4.3.

According to the results of thermogravimetry, the weight loss of the polyamide is 3% at 200 ° C, 3.50 / o at 300 ° C, 6% at 400 ° C and 12% at 500 ° C. Off films and fibers are obtained from the polyamide.

Example 6

The synthesis of the polyamide is based on the diamine of the formula

H ₂ N

and the 2,6-naphtha-indica-carboxylic acid dichloride analog

Example 1. The polyamide obtained has a specific viscosity of 2.2 and can be used in films and Fibers are further processed.

Comparative experiments

1. For the production of an aromatic according to the application A four-necked flask with a volume of 0.5 liters was provided with polyamide a stirrer, metering device and inlet pipe for dry nitrogen, with 11.20 g (0.05 moles) 2- (4-aminophenyl) -5-aminobenzimidazole and 336 ml of N-methylpyrrolidone, which is 5% LiCl and dehydrated after dissolving the LiCl in vacuo to a residual moisture content of 0.1% had been loaded. The diamine solution became 12.6 g at 16 to 20 ° C over 1.5 hours (0.05 mol) 2,6-naphthalenedicarboxylic acid dichloride added. The obtained polyamide had a specific viscosity of 4.3.

2. That in Vysokomol. Soedin "Ger. A 1970, 12 (10), 2205-2210, the aromatic polyamide described was obtained as indicated under 1. from 11 ^ 20 g (0.05 mol) 2- (4-aminophenyl) -5-aminobenzimidazole and 10.15 g (0.05 mol) terephthalic acid dichloride below Using 300 ml of the same LiCl solution made in N-methylpyrrolidone. Its specific Viscosity was 4.0.

3a. To prepare an aromatic polyamide described in DE-OS 17 20 650, the device mentioned under 1. with 11.25 g (0.05 mol) of N-2- (3-aminophenyl) -5-aminobenzotriazole and 295 ml of Ν, Ν-dimethylacetamide. which contained 5% LiCl and had a residual moisture content of 0.08%. 10.15 g (0.05 mol) of terephthalic acid dichloride were added to the diamine solution in the course of 0.5 hours. During the addition of the dichloride, the temperature was 18 ° C .; then increased to 35 ° to 4O ⁰ C. The stirring time was 2.5 hours. The polyamide obtained had a specific viscosity of 1.50.

3b. An aromatic polyamide with a specific viscosity of only 0.7 was obtained when below ■ "> 3a. The Ν, Ν'-dimethylacetamide by 400 ml of the

under!. used LiCl solution in N-methylpyrrolidone was replaced, the duration of the dichloride addition was 1.5 hours and the polycondensation temperature was 18 to 20 ° C.

κι 4a. Another in DE-OS 17 20 650 described aromatic polyamide as under 3a. given from 11.25 g (0.05 mol) of N-2- (3-minophenyl) -5-aminobenzotriazole and 12.60 g (0.05 mol) of 2,6-naphthalenedicarboxylic acid dichloride under

ii application of 336ml of the same LiCl solution in

Ν, Ν'-dimethylacetamide produced. Its specific viscosity was 1.81.

4b. That from the under 4a. named monomers using working variant 3b. manufactured

λι aromatic polyamide had a specific

Viscosity of 0.9.

The precipitation, washing and drying of the aroma obtained in the comparative experiments and examples

R> table polyamides were done in the same way. The specific viscosities were always determined at a concentration of 0.5% polyamide in 96% strength H2SO4 at 2O ⁰ C.

From those obtained in the comparative experiments

ju polyamides were made under comparable conditions Fibers made. 5.2% solutions of the polyamides in Ν, Ν'-dimethylacetamide were added at a rate of 10.2 m / min in a precipitation bath of water and Ν, Ν'-dimethylacetamide in a ratio of 1: 1.

r> presses. The thread emerging from the precipitation bath was between two at different speeds rotating disks stretched. The properties of the threads obtained are as follows Table I.

Table I.

Polyamide thread

Strength fineness elongation double resistance of the

g / d in d in% bends strength in%

at b at 300 ° C and

= 12 kg / mm heating for 7 min

-HN

CO-

16-18 30.7

10-12 31

3.5

2.8

8000

720

69

60

-HN

V-CO-

31.3

25th

57

-HN

31.0

1.7

28

40

Claims (1)

Claim: Aromatic polyamides with specific viscosities (determined in 96% H ₂ SO ₄ at 20 ^° C. and a concentration of the polyamide of 0.5 g / 100 ml solvent) between 2 and 20, obtained by the polycondensation of 2.5-, 2 , 6- or 2,7-naphthalenedicarboxylic acid dichloride with