RU2476452C1 - Method of producing curing agents of epoxy resins - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing curing agents of epoxy resins involving an operation for reacting amines with monocarboxylic acids. The method is characterised by that the amine component used is a mixture consisting of a primary aromatic amine or a mixture of aromatic amines (A), a secondary aliphatic amino alcohol (B) and a tertiary aliphatic amino alcohol (C) in weight ratio A:B:C from 98:0.2:1.8 to 80:5:15. The monocarboxylic acid (D) is used in form of a 25-80% solution in a monoatomic aliphatic or aromatic alcohol, or ester thereof with a mono- or dicarboxylic acid, in ratio (A+B+C):D from 90:10 to 60:40 per 100% acid. The reaction process is then carried out by mixing in a reactor at temperature ranging from 50 to 130°C for 20 to 120 minutes and speed of the mixer of 100 to 3000 rpm.

EFFECT: curing agents obtained using said method have high stability during storage.

1 cl, 7 ex, 1 tbl

Description

The invention relates to the field of producing hardeners of epoxy resins used in the preparation of casting and impregnating compounds, binders for reinforced composites, paints and other purposes.

The closest prototype of the claimed invention is a method for producing hardeners of epoxy resins, including the process of interaction of an amine with salicylic acid (Patent RU 2207379).

The disadvantages of the prototype are the short shelf life of the obtained hardeners - 1 ÷ 2 months, the low viability of the epoxy compositions containing it, as well as the relatively high decrease in strength and dielectric properties after simultaneous exposure to 100% humidity and elevated temperatures.

The aim of the invention is to increase the storage stability of the obtained hardeners, improve the technological properties of the cured compositions and increase the strength and dielectric properties after prolonged simultaneous exposure to 100% humidity and elevated temperatures.

This goal is achieved by the fact that when implementing the method for producing a hardener of epoxy resins, including the operation of the interaction of amines with monocarboxylic acids, the mixture consisting of a primary aromatic amine or a mixture of aromatic amines (A), secondary aliphatic amino alcohol (B) and tertiary is used as an amine component aliphatic amino alcohol (B) in a mass ratio of A: B: C from 98: 0.2: 1.8 to 80: 5: 15, and monocarboxylic acid (G) is introduced as a 25 ÷ 80% solution in a monoatomic aliphatic or aromatic with pirte, or their ether with mono- or dicarboxylic acid, in the ratio (A + B + C): D from 90:10 to 60:40 in terms of 100% acid, while the interaction process is carried out by stirring in a reactor at a temperature of 50 ° C to 150 ° C for 20 to 120 minutes and stirrer speeds of 100 to 3000 rpm.

Example 1

In a reactor equipped with heating, cooling and a high-speed stirrer, 3 ingredients included in the amine component are alternately charged - metaphenylenediamine (A), secondary amino alcohol - diisopropanolamine (B) and tertiary amino alcohol - N, N 'diisopropanylethanolamine (C) in a mass ratio A : B: C = 88: 2.6: 9.4. The mixture is stirred at 100 ° C for 5 minutes at 1500 rpm of the working mixer. Then, butyric acid (G) is added to the reactor in the form of a 50% solution in ethanol in the ratio (A + B + C): G = 75: 25 in terms of 100% acid and, while maintaining the temperature at 100 ° C with the stirrer operating, carry out interaction for 60 minutes.

The resulting product is poured into metal containers and stored in storage conditions. The validated shelf life is 6 months.

Examples 2 ÷ 7 carry out analogously to example 1 with a change in composition, and parameters in accordance with table 1.

The properties of the compositions containing hardeners according to examples 1 ÷ 7 and epoxy Diane resin brand ED-20 and its American counterpart DER-331 are presented in table 2.

table 2 The properties of hardeners obtained by the present method, and an epoxy composition based on diane resin ED-20 (numerator) and its American counterpart DER-331 (denominator) No. p / p Name of indicator The value of the indicator for examples 1 ÷ 7 and prototype one 2 3 four 5 6 7 prototype one. Shelf life of hardener in storage conditions Not less than 6 months 1 month 2. Composition viability at 20 ° C, min 120 one hundred 110 120 140 90 130 130 at 60 ° C, min 3. Curing time at 20 ° C, hour fourteen 12 12 10 24 8 24 24 four. The indicators of the cured compositions in the cold state; tensile strength - in tension, MPa;

98 one hundred 105 96 95

- under compression, MPa;

165 155 160 165 165

- electrical resistivity;

9 · 10 ¹⁵ 8.50 · 10 ¹⁴ 9 · 10 ¹⁴ 8 · 10 ¹⁴ 6 · 10 ¹⁴

dielectric loss tangent

0.013 0.012 0.014 0.012 0.012

5. Cured compositions after 30 days exposure to T = 80 ° C and 100% humidity: - in tension, MPa;

96 105 94 96 98

- under compression, MPa

170 165 170 160 158 110 120 6 Volume resistivity, Ohm · cm

4 · 10 ¹⁴ 5 · 10 ¹⁴ 2 · 10 ¹⁴

Dielectric loss angle

0,020 0,021 0,022 0,021 0,020

Claims (1)

A method of producing hardeners of epoxy resins, including the operation of the interaction of amines with monocarboxylic acids, characterized in that as an amine component a mixture is used consisting of a primary aromatic amine or a mixture of aromatic amines (A), a secondary aliphatic amino alcohol (B) and a tertiary aliphatic amino alcohol (C ) in a mass ratio of A: B: C from 98: 0.2: 1.8 to 80: 5: 15, and monocarboxylic acid (G) is introduced in the form of a 25 ÷ 80% solution in a monohydric aliphatic or aromatic alcohol, or their broadcast with mono or d carboxylic acid in the ratio (A + B + C): D from 90:10 to 60:40 in terms of 100% acid, then the interaction process is carried out by stirring in a reactor at a temperature of from 50 to 130 ° C for 20 up to 120 min and stirrer speeds from 100 to 3000 rpm.