RU2570434C1 - Epoxy composition and method for thereof production - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: epoxy composition for infusion technology contains epoxy oligomer, selected from the group, which includes tri-tetrafunctional epoxy oligomers and eutectic mixture of, at least, two diamines, selected from the group, which includes diaminodiphenylsulphone, 3,3'-dichloro-4,4'-diaminodiphenylmethane, 4,4'-methylene-bis-(3-chloro-2,6,-diethylaniline) and 4,4'-methylene-bis-2,6,-diethylaniline, 4,4'-methylene-bis-2-isopropyl-6-methylaniline and 4,4'-methylene-bis-2,6,-diisopropylaniline. The invention also describes method of said composition obtaining.

EFFECT: invention makes it possible to obtain epoxy composition for obtaining bulky products by method of vacuum infusion with high complex of properties, realised by regulation of soaking speed, with variation of ratio of epoxy oligomers of various chemical structure and viscosity at different ratio of hardeners in mixture, as well as modes of hardening at different temperatures.

4 cl, 1 dwg, 2 tbl

Description

Technical field

The invention relates to epoxy compositions and can be used for the manufacture of products from polymer composite materials (PCM), in particular large and complex shapes, by vacuum infusion and RTM technology (pressure impregnation).

State of the art

Epoxy compositions with amine hardeners are widely represented in the prior art. They are widely used in the production of polymer composite materials.

SU 517612 discloses an epoxy composition containing 50.4 57.8 wt.% Epoxy resin and an amine hardener - the rest, where a mixture of condensation products of polyepichlorohydrin-di- (2,3-epoxypropyl) ether with 3,3′-dichloro-4,4′-diaminotriphenylmethane and 3,3′-dichloro-4,4′-diaminodiphenylmethane taken in a specific weight ratio.

This composition is characterized by high viability and impact strength and has been used as a binder for the manufacture of winding fiberglass obtained by dry or wet methods.

The copyright certificate SU 1014859 discloses an epoxy composition that can be used in the manufacture of large PCMs not subjected to heat treatment. The composition contains the following components, weight. h: epoxy diane resin 0-93, diglycidyl ether polyepichlorohydrin 5, diglycidyl ether diethylene glycol 2-20, liquid eutectic mixture of aromatic amines 12-5, salicylic acid 0.5-5.

The composition is prepared in the following way: an epoxy diane resin, polypichlorohydrin diglycidyl ether, a three-component liquid eutectic mixture of aromatic amines and salicylic acid dissolved in diethylene glycol diglycidyl ether are successively charged to the reactor.

The mixture is stirred, then poured into molds and cured at room temperature.

As follows from the description of the well-known copyright certificate, the purpose of this invention is to reduce the curing temperature and increase the physico-mechanical properties.

The disadvantages of these two epoxy compositions include the impossibility of using them for infusion technologies of large-sized parts carried out on a heated matrix in order to control the speed of impregnation and achieve uniformity of wetting of the filler by adjusting the viscosity of the composition, time of impregnation and temperature of the binder to achieve the best strength characteristics. The impossibility of applying the above technical solutions is associated with the proposed technical solution aimed at accelerating the curing process of large-sized thick-walled products, such as boats, yachts, small vessels, where the main factor is curing at room temperature, due to the high reactivity of the hardener mixture, which leads to low stability in a large volume of a binder, in which both an epoxy oligomer and a reactive hardener are simultaneously present, during the impregnation process. In this case, the infusion process is carried out as quickly as possible, without taking into account the formation of some porosity, which can reduce the strength characteristics of the product.

Partially, these disadvantages are eliminated by the composition in accordance with patent RU 2488612. This epoxy composition for vacuum infusion includes an epoxy base containing epoxy Dianova resin, which is used as a resin or a mixture of resins with a molecular weight of 340-430; an active diluent with a viscosity of up to 0.1 Pa · s and a curing system based on an amine hardener, a surfactant, an imidazole type heterocyclic compound and a nanomodifier, where a mixture of a hardener based on aromatic amine and a cold curing catalyst is used as an amine hardener.

A method of manufacturing this composition provides for:

obtaining a liquid epoxy base by sequentially loading into the reactor an epoxy diane resin with a molecular weight of not more than 340 (ED-22 brand resin) and an active diluent with a viscosity of not more than 0.1 Pa · s (E-181 resin), followed by mixing of the loaded components, heating to a temperature of (50 ± 5) ° C and re-mixing;

obtaining a liquid curing system by sequentially loading into the reactor an aromatic type hardener with a catalyst (XT-450/1), an imidazole type heterocyclic compound (2-methylimidazole), a surfactant and a nanomodifier (TAUNIT-M multilayer carbon nanotubes), followed by mixing the loaded components at a temperature of (60 ± 5) ° C to combine the components;

obtaining an epoxy composition by combining a liquid epoxy base and a curing system.

As follows from the description of this patent, the technical result of the known invention is the creation of a high-tech epoxy composition capable of curing without adding additional heat and without a large exothermic effect, characterized by high physical and mechanical characteristics. The composition is characterized by high values of the elastic modulus of 3.8-4.2 GPa, which ensures the creation on its basis of deformation-resistant products from PCM with a higher level of structural strength.

The disadvantages of this composition include the choice of a binder based on diane epoxy resin ED-22 and diluent E-181, which upon curing at room temperature do not provide heat resistance of the composite material to more than 80 ° C. When replacing hardeners and catalysts in this technical solution, in order to increase the heat resistance of the polymer composite material obtained by vacuum infusion, it is possible to decrease the strength indices as compared with the declared ones, as well as in comparison with epoxy compositions based on tri- and tetrafunctional epoxies, which provide high strength characteristics , so heat resistance of more than 150 ° C.

Disclosure of invention

The objective of the invention is to provide an epoxy composition for producing large-sized products by vacuum infusion on a heated matrix with a high set of properties realized by controlling the speed of impregnation, while varying the ratio of epoxy oligomers of different chemical structures and viscosities at different ratios of hardeners in the mixture, as well as curing conditions for various temperatures from 160 to 200 ° C

The problem is solved by the epoxy composition for infusion technology, in accordance with which it contains an epoxy oligomer selected from the group comprising tri- and tetrafunctional epoxy oligomers and a eutectic mixture of at least two diamines selected from the group comprising diaminodiphenyl sulfone, 3.3 ′ -Dichloro-4,4′-diaminodiphenylmethane, 4,4′-methylene-bis- (3-chloro-2,6, diethylaniline), 4,4′-methylene-bis-2,6, diethylaniline, 4 , 4′-methylene-bis-2-isopropyl-6-methylaniline, 4,4′-methylene-bis-2,6, -diisopropylaniline. In private embodiments of the invention, the problem is solved by the composition in accordance with which it contains an epoxy oligomer and a eutectic mixture of amines in an equimolar ratio.

The problem is also solved by a method of manufacturing an epoxy composition for infusion technology, including pre-sintering of diamines selected from the group containing at least two diamines selected from the group comprising diaminodiphenylsulfone, 3,3′-dichloro-4,4′-diaminodiphenylmethane , 4,4′-methylene-bis- (3-chloro-2,6, -diethanilinil), 4,4′-methylene-bis-2,6, -diethylaniline, 4,4′-methylene-bis-2- isopropyl-6-methylaniline and 4,4′-methylene-bis-2,6, -diisopropylaniline, at the melting point of the lowest melting diamine to obtain eutectic eskoy mixture, followed by cooling with the crystallization mixture and the subsequent introduction of said crystallized eutectic mixture in molten epoxy oligomer, followed by dissolving it in said oligomer selected from the group consisting of tri- and tetrafunctional epoxy oligomers.

In particular embodiments, the introduction of said crystallized eutectic mixture is carried out in an epoxy oligomer molten at 40-60 ° C.

The implementation of the invention

The qualitative composition of the epoxy composition was selected from the following considerations. Three- and four-functional resins were chosen as the epoxy component of the composition, since they are the most high-strength and heat-resistant and are recommended by manufacturers for use in critical assemblies of structural products.

For these resins, a special amine hardener composition was selected, which is a eutectic mixture of at least two diamines selected from the group consisting of diaminodiphenylsulfone, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 4,4′-methylene bis (3-chloro-2,6, diethylaniline), 4,4′-methylenebis-2,6, diethylaniline, 4,4′-methylene-bis-2-isopropyl-6-methylaniline, 4,4 ′ -Methylene-bis-2,6, -diisopropylaniline.

The hardener composition is selected from the following considerations: all of the above diamines are latent, which allows you to store and use an epoxy binder for a long time, and their variant set enhances the characteristics of each of them, since the selected amines contain functional and side groups that provide minimal moisture absorption, the greatest relative elongation and high elastic modulus, which is achieved when the least defective three-dimensional structure is formed during the course of the curing reaction, sterically hindered at the gelation stage, due to the presence of side or functional groups and the formation of a more ordered structure of linear sections of the chain.

The quantitative ratio of the components in the curing system must be selected so that the components form a eutectic mixture and can be easily calculated from the state diagrams of the respective mixtures. As a rule, the ratio of diamines in the mixture varies from 30 to 70 mass. hours in binary systems and from 10-20 to 40-45 mass. hours in ternary systems. The epoxy composition exhibits the best properties when the epoxy component and the curing system are contained in or near the equimolar ratio.

To implement the proposed method, it is important that upon receipt of the curing system, pre-sintering of diamines selected from the group comprising at least two diamines selected from the group consisting of diaminodiphenylsulfone, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 4,4′-methylene-bis- (3-chloro-2,6, -diethylaniline), 4,4′-methylene-bis-2,6, -diethylaniline, 4,4′-methylene-bis-2-isopropyl -6-methylaniline and 4,4′-methylene-bis-2,6, -diisopropylaniline at the melting point of the lowest melting diamine, which provides eutectic mixtures in the most economical way, and also allows to achieve the most uniform distribution of all components in the mixture during sintering.

To implement the method, it is also important to cool the resulting eutectic mixture for its crystallization and introduce the resulting mixture into the melt of tri- and tetrafunctional epoxy oligomers in a crystallized state, which ensures its dissolution in the epoxy oligomer at lower temperatures than when the components of the curing system are introduced.

Obtained in accordance with the invention, the epoxy composition can be stored and used for a long time, which is especially true in the manufacture of large-sized products or products of complex shape.

Infusion impregnation can be carried out for a long time at temperatures at which the minimum viscosity is achieved, which allows to obtain a composite with higher strength characteristics, and curing the epoxy composition is carried out not during the manufacture of products, but after impregnation with precise control of temperature and temperature compensation for possible overheating bulky products.

The invention is illustrated in tables 1 and 2 and figure 1.

Table 1 shows the compositions of the epoxy compositions in accordance with the invention.

Table 2 shows the properties of the obtained compositions depending on the compositions.

In fig. 1 shows thermograms of a mixture of diamines in various proportions:

1 - MOKA; 2 - M-CDEA; 3 - MOKA / M-HDEA = 50/50; 4 - MOKA / M-HDEA = 70/30; 5 - MOKA / M-HDEA = 30/70.

The invention is as follows.

For the manufacture of the epoxy composition, diamines with various chemical structures were selected, the melting point of which was from 88 to 180 ° C, and epoxy oligomers selected from the group comprising tri- and tetrafunctional epoxy oligomers, the composition of which is shown in table 1.

The composition was prepared in accordance with the following.

At a temperature of 80-100 ° C (depending on the selected eutectic mixture), the selected diamines were sequentially loaded in a predetermined amount to obtain a eutectic mixture, the loaded components were mixed with a stirrer at a speed of 60 s ^-1 and sintered at the melting temperature of the lowest melting diamine. The resulting eutectic mixture was cooled to effect crystallization. Then, the crystallized eutectic mixture of diamines was discharged from the reactor and placed in a container, from which it was introduced into the heated epoxy oligomer in a predetermined ratio and mixed.

As follows from fig. 1, with the joint introduction of diamines with different melting points, the melting point of the mixture decreases, which leads to better dissolution of the hardener in an epoxy oligomer.

The study of the mixture of amines by differential scanning calorimetry showed that all mixtures of MOCA and M-CDEA have a melting point two times lower than for the starting diamines. Similar dependences were obtained for the other pairs studied.

In addition, the introduction of a mixture of hardeners leads to an improvement in water absorption and strength characteristics of cured matrices compared to the initial diamines of the selected structure (see table 2).

Claims (4)

1. An epoxy composition for infusion technology, characterized in that it contains an epoxy oligomer selected from the group comprising tri- and tetrafunctional epoxy oligomers and a eutectic mixture of at least two diamines selected from the group comprising diaminodiphenylsulfone, 3.3 ′ -dichloro-4,4′-diaminodiphenylmethane, 4,4′-methylene-bis- (3-chloro-2,6, diethylaniline), 4,4′-methylene-bis-2,6,-diethylaniline, 4, 4′-methylene-bis-2-isopropyl-6-methylaniline and 4,4′-methylene-bis-2,6, -diisopropylaniline. 2. The composition according to p. 1, characterized in that it contains an epoxy oligomer and a eutectic mixture in an equimolar ratio. 3. A method of manufacturing an epoxy composition for infusion technology, characterized in that it includes pre-sintering of diamines selected from the group consisting of at least two diamines selected from the group comprising diaminodiphenylsulfone, 3,3′-dichloro-4,4 ′ -diaminodiphenylmethane, 4,4′-methylene-bis- (3-chloro-2,6, -diethylaniline), 4,4′-methylene-bis-2,6, -diethylaniline, 4,4′-methylene-bis- 2-isopropyl-6-methylaniline and 4,4′-methylene-bis-2,6, -diisopropylaniline, at the melting point of the lowest melting diamine to obtain a eutectic mixture , Followed by cooling with the crystallization mixture and the subsequent introduction of said crystallized eutectic mixture in molten epoxy oligomer, followed by dissolving it in said oligomer selected from the group consisting of tri- and tetrafunctional epoxy oligomers. 4. The method according to p. 4, characterized in that the introduction of the said crystallized eutectic mixture is carried out in a molten epoxy oligomer at 40-60 ° C.

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