CH631727A5 - Process for the preparation of copolyamides - Google Patents

Description

35 The present invention relates to a process for the preparation of copolyamides from isophthalic acid, and optionally terephthalic acid and hexamethylenediamine and cyclic aliphatic diamines.

Polyamides made from isophthalic acid and hexamethylenediamine

40 known from US-PS 2715 620 and 2742496. However, the dimensional stability at higher temperatures or the glass transition temperature of these polyamides are not sufficient for many areas of application. To solve this problem, it has been proposed to use terephthalic acid in the polycondensation.

This measure increases the melting temperature of the products, but does not increase the freezing temperature. However, the freezing temperature is the decisive criterion for assessing the thermal load capacity of amorphous polymers.

50 Surprisingly, it has now been found that the freezing temperature of polyamides from isophthalic acid and hexamethylenediamine can be increased by partially replacing hexamethylenediamine with cyclic aliphatic diamines.

The invention accordingly relates to a process for the preparation of copolyamides, consisting of

A) 50-99.9 mol%, preferably 90-90 mol%, of unit

2) the rest of bis (aminocyclohexyl) alkanes of the formula ten of the structure

(R ') 2

-; - 0 -! <> ■ -

60

65

With

R 'is hydrogen or methyl, where the two radicals R' can be the same or different, and / or h

H

-c-n- (ch0), - n-2 6

3rd

631 727

and if necessary

B) 50-0.1 mol%, preferably 40-10 mol%, of units of the structure and optionally where

R 1) the residue of at least one cycloaliphatic diamine of the formula

. HN- (CH3) y with y 0 or an integer from 1-3 and x 0 or 1 and / or

2) the rest of bis (aminocyclohexyl) alkanes of the formula

(Rl) 2

iO-l-O-S-

With

R 'is hydrogen or methyl, the two radicals R'

can be the same or different, and / or

3) the rest of a residue of a heterocyclic amine of the formula

/ \ «O

-N N- (Rr> 7

65

With

R "methyl or ethyl and the radicals R" may be the same or different, and

Z means 0 or an integer from 1-2.

A and B, or 1), 2) and 3) give 100 mol%.

The process according to the invention is characterized in that the mixture of isophthalic acid and optionally terephthalic acid and hexamethylenediamine and at least one of the diamines mentioned is first heated to temperatures between 190 ° C. and 230 ° C. and after this precondensation has ended at temperatures between 240 ° C. and 300 ° C polycondensed to the end.

The precondensation can be carried out with or without the addition of water; it can be carried out at atmospheric pressure or in closed autoclaves under the vapor pressure of the water.

It is advantageous to carry out the polycondensation starting from the salts from the monomers.

The amine mixture is composed in particular of 50-99.9, preferably 60-90, mol% of hexamethylenediamine and 50-0.1, preferably 40-10, mol% of the other diamines.

The optimal quantitative ratio between hexamethylenediamine and the cyclic aliphatic diamines depends to a certain extent on the diamines additionally used.

Losses of diamine occurring during the polycondensation are normally compensated for by using an appropriate excess of hexamethylenediamine.

As cyclic, aliphatic diamines are preferably diamines with 6-10 carbon atoms, such as. B. 1,4-diamino-cyclohexane, 4-amino-methylcyclohexylamine, 3-aminomethyl-3,5,5-trimethylcyclohexylamine, bis- (amino-cyclohexyl) alkanes with C] 3-Cj5 such as e.g. B. bis (4-amino-cyclohexyl) methane, bis (4-aminocyclohexyl) propane, and / or heterocyclic diamines with C4-C8 such as e.g. Piperazine.

Up to 10 mol%, preferably 5 mol%, of the isophthalic acid can be replaced by terephthalic acid without the properties of the copolyamides changing significantly.

The molecular weight of the polyamides can be regulated by carboxylic acids or amines, preferably by benzoic acid or sebazic acid.

The relative solution viscosity of the copolyamides obtained and obtainable according to the invention is normally> 2, measured on a 1% strength solution of the polyamide in m-cresol at 25 ° C. in an Ubbelohde viscometer. The copolyamides are transparent and can be processed thermoplastically without difficulty. Auxiliaries and additives can be added to the copolyamides, for example lubricants, mold release agents, dyes, glass fibers, fillers, fire retardants. The copolyamides are used to manufacture moldings such as fibers, foils, plates, and injection molded parts.

example 1

101.6 g (0.36 mol) of a salt of hexamethylenediamine and isophthalic acid and 11.21 g (0.04 mol) of a salt of 1,4-diaminocyclohexane and isophthalic acid are heated with the addition of 0.84 g (2 wt. -%, based on the proportion of hexamethylenediamine) Hexamethylenediamine with stirring in a nitrogen atmosphere for 2 h to 220 ° C and then for 3 h to 270 ° C. The result is a transparent copolyamide with a relative solution viscosity of 3.1, measured on a 1% solution of the polyamide in m-cresol at 25 ° C in an Ubbelohde viscometer.

The freezing temperature of this copolyamide and some other transparent copolyamides, which were prepared as stated but with different molar ratios of hexamethylenediamine to 1,4-diamino-cyclohexane, was determined by differential thermal analysis and compiled in the following table.

631 727

4th

Molar ratio of freezing hexamethalediamine: 1,4-diaminocyclo temperature hexane (° C)

100

0

130

99

1

132

95

5

135

90

10th

143

85

15

148

80

20th

149

clohexylamine produced by varying the molar ratio of the diamine components. The corresponding freezing temperatures can be found in the table below.

5 molar ratio of freezing hexamethylene diamine: 4-aminomethyl cyclo temperature hexylamine (° C)

90: 10-140

I0 80: 20 150

Example 2 Comparative Example Mixtures of salts of isophthalic acid and hexamethylenediamine and terephthalic acid and hexamethylenediamine are polycondensed as described in Example 1. The addition of 2% by weight of hexamethylene diamine (based on the hexamethylene diamine used) compensates for the loss of diamine. The molecular weight is regulated by 0.5 mol of benzoic acid (based on 100 mol of salt). The following table shows the dependence of the glass transition temperature on the mixing ratio of isophthalic acid to terephthalic acid.

Molar ratio freezing temperature! 5 isophthalic acid: terephthalic acid (° C)

60: 40

70:30

75: 25

85: 15

95: 5

Example 3 "

Analogous to Example 1, transparent copolyamides were prepared from isophthalic acid, hexamethylenediamine and bis- (4-amino-cyclo-hexyl) methane, the molar ratio of the diamine components being varied according to the table below and the corresponding freezing temperatures being determined by differential thermal analysis

Molar ratio of freezing hexamethylene diamine: bis (4-aminocyclo temperature hexyl) methane (° C) 45

95:

5

136

90:

: 10

139

80:

: 20

152

70:

: 30

165

60:

: 40

176

Example 4

According to Example 1, transparent copolyamides from isophthalic acid, hexamethylenediamine and 4-aminomethylcy-

Example 5

Transparent copolyamides made from isophthalic acid, hexamethylene diamine and 3-aminomethyl-3,5,5-trimethylcyclohexylamine were prepared in accordance with Example 1 and their freezing temperature was determined after the differential thermal analysis.

Molar ratio of freezing hexamethylene diamine: 3-aminomethyl-3,5,5-temperature trimethylcyclohexylamine (° C)

90

10th

143

70

30th

167

60

40

181

Example 6

A transparent copolyamide made from isophthalic acid, hexamethylenediamine and piperazine was produced according to Example 1 and the glass transition temperature was determined by differential thermal analysis.

Molar ratio freezing temperature hexamethylenediamine: piperazine (° C)

90: 10 135

Example 7

The salts of isophthalic acid and hexamethylenediamine, isophthalic acid and 3-aminomethyl-3,5,5-trimethylcyclohexylamine and from isophthalic acid and 1,4-diaminocyclohexane were in a molar ratio of 80:10:10 for 2 hours at 220 ° C. and for 3 hours at 270 ° C polycondensed while stirring in a nitrogen atmosphere. A transparent copolyamide with a glass transition temperature of 154 ° C. was obtained.

Example 8

As in Example 7, a transparent copolyamide was made from isophthalic acid, hexamethylene diamine, 1,4-diaminocyclohexane and bis (4-aminocyclohexyl) methane. The molar ratio of the diamines or the salts with isophthalic acid was 80:10:10.

The copolyamide has a freezing temperature of 153 ° C.

133 132 132 132 132

M

Claims (3)

631 727 2nd out PATENT CLAIMS 1. Process for the production of copolyamides, consisting of s A) 50-99.9 mol% of units of structure h -c-n- (ch2) 6- H -N- and possibly o h h —C-n- (ch2) g-n- B) 50-0.1 mole% of units of the structure 3) the residue of a heterocyclic amine of the formula -N N- M7 (R ">, with io R "methyl or ethyl and the radicals R" may be the same or different, and Z is 0 or an integer from 1-2, characterized in that the mixture of isophthalic acid and optionally terephthalic acid and hexais methylenediamine and at least one of the diamines mentioned is first heated to temperatures between 190 ° C and 230 ° C and after the end of this precondensation at temperatures between 240 ° C and 300 ° C to the end . 2. The method according to claim 1, characterized in that R is 1,4-diaminocyclohexane, 4-aminomethylcyclo- hexylamine, bis (4-aminocyclohexyl) methane, bis (4-aminocyclohexyl) propane, 3-aminomethyl-3,5,5-trimethyl-cyclohexyl-amine or piperazine. 3. The method according to any one of claims 1 to 2, characterized in that the reaction components in such Amounts are used that part A) 60-90 mol%. and part B) is 40-10 mol%. 30th and optionally O in which R 1) the residue of at least one cycloaliphatic diamine of the formula 45 (ch2) x-nh- (CH3) y y X With 0 or an integer from 1-3 and 0 or 1 and / or