RU2587169C1 - Epoxy-bis-maleimide resin composition and preparation method thereof - Google Patents

Abstract

FIELD: chemistry; aviation.

SUBSTANCE: invention relates to production of polymer composite materials used in aerospace engineering, particularly to composition of epoxybismaleimide resin and method of producing composition. Composition of epoxybismaleimide resin contains, wt%: 29.2-47.6 Ν,Ν,Ν′,Ν′-triglycidyl-4,4′-diamino-3,3′-dichlorodiphenylmethane, 10.9-27.1 of triglycidylparaaminophenol as polyfunctional epoxy resins; 0.5-2.1 of paraaminophenol as catalyst; 13.9-15.8 Ν,Ν′-hexamethylenebismaleimide as bismaleimide and 20.9-30.6 4,4′-diaminodiphenylsulfone as solidifier. Method of producing epoxybismaleimide resin involves mixing components by heating. First, into reactor, heated to temperature of 90±5°C, successively added while stirring Ν,Ν,Ν′,Ν′-triglycidyl-4,4′-diamino-3,3′-dichlorodiphenylmethane, triglycidylparaaminophenol and paraaminophenol, preheated to temperature 100±5 °C, 65±5 °C and 60±5 °C, and produced mixture is stirred for 17.5±2.5 min at temperature of 90±5 °C, and then obtained mixture is added with powdered 4,4′-diaminodiphenylsulfone for minimum time sufficient for its dissolution, obtained liquid mixture is first mixed for 17.5±2.5 min maintaining temperature of mixture 120±5 °C, then, proceeding with stirring, mixture is cooled to temperature 100±5 °C and addition of powdered Ν,Ν′-hexamethylene bismaleimide for minimal time, sufficient for its dissolution, followed by stirring of obtained liquid mixture for 12.5±2.5 min and mixture temperature of 85±5 °C.

EFFECT: obtaining a composition epoxybismaleimide resin with high crack resistance by relatively simple and low-energy consumption method.

2 cl, 1 tbl, 5 ex

Description

The invention relates to the development of a chemical composition and method for producing an epoxybismaleimide resin, is used as a matrix in the manufacture of polymer composite materials used in aerospace engineering.

Known epoxybismaleimide resins, which are one of the best types of binders for the manufacture of high-quality composite materials based on dispersed or continuous inorganic or organic fibrous fillers - glass, carbon - and organoplastics.

These resins usually consist of a mixture of polyfunctional epoxides, bismaleimides and aromatic amines used as hardeners, as well as modifying additives that improve certain properties of epoxyimide resins [Patel R.N. "Termosetting Polyimides: A Review" // SAMPE Journal, Vol. 30, No. 5, p. 29, 1994].

For example, polyepoxides containing two or more epoxy groups are used as the epoxy component of the epoxyimide resin composition. The bismaleimide components used are mainly bismaleimides based on aromatic diamines. As the amine component hardener, for example, polyfunctional aromatic amines containing two or more primary amino groups are used. Phenol-formaldehyde resins, unsaturated (vinyl, allyl, isopropenyl) phenol esters, siloxane resins, aromatic polycyanates, thermoplastics, etc. are most often used as modifying additives. The very idea of combining epoxy and bismaleimide resins in one composition, as well as modifying them with additives, aims to increase heat resistance both in the case of an increase in the glass transition temperature and in the case of an increase in the temperature of long-term operation, as well as in terms of increasing the strength and stiffness of the resulting resins. This increase has indeed been achieved, and a number of compositions of this kind are widely used in the aerospace field in the form of matrices for glass and carbon fiber [1) ASM Handbook Volume 21: Composites (ASM International) p. 78, 97, 914 (2001); 2) CPR Nair, Prog. Polym. Sci, 29, p. 423, 456 (2004); 3) Long-Term Durability of Polymeriv Matrix Composites, Ed-rs: Kishore V. Pochraju et al., Springer, 2012, p. 1-38], however, a fundamental improvement of the most important properties of thermosets - crack resistance - in the case of the aforementioned modified epoxy, bismaleimide and epoxybismaleimide resins could not be achieved. Fracture resistance or the fracture energy measuring it (G _1C ) of almost all heat-resistant and high-strength thermosets, including epoxy, bismaleimide and epoxybismaleimide resins, is almost exclusively at the level of 0.05-0.9 KJ / m ² , while for heat-resistant and high-strength thermoplastics that compete in the binder market for polymer composites with thermosets, the energy of destruction is mainly in the range of 2-3 KJ / m ² [1) A.A. Kuznetsov et al. “Promising high-temperature thermosetting binders for polymer composite materials” // Russian Chemical Journal, 2009, V. 53, No. 4, p. 86-96; 2) F. Christie “Determination of the matrix standard for enhancing the temperature resistance of epoxy prepregs” // Composite World, No. 6, p. 46, 2013; 3) D. Ratna, Handbook of Thermoset Resins, iSmithers, UK, p. 117, 2009].

In particular, in the field of thermosetting binders for high-quality polymer composite materials used in the aerospace field, well-known and well-established resins based on polyepoxides and bismaleimides of the CYCOM PR 520 RTM Resin System and CYCOM 5250-4 RTM Resin System brands manufactured by Cytec are used. Engineered Materials USA, Arizona, which are analogues of the present invention in terms of resin composition. Both resins are high-tech, have good heat resistance and mechanical characteristics, but they also have a significant drawback, because their crack resistance is low; resin CYCOM PR 520 has a fracture energy G _1C ≈ 1.01 KJ / m ² and resin CYCOM 5250-4 G _1C ≈0.14 KJ / m ² .

Numerous studies in the field of producing crack-resistant epoxybismaleimide resins experimentally show and theoretically substantiate that it is not only impossible to increase the crack resistance of epoxybismaleimide resins by mixing epoxy and bismaleimide resins, but the value of the fracture energy G _{1C of} the resulting epoxyimide resin should become even slightly less than that of any from the original epoxy or bismaleimide resins [P. Musto et al. Thermal-Oxidativ Degradation of Epoxy and Epoxy Bismaleimide Networks: Kinetics and Mechanism, Macromol. Chem. Phys., 2001, 202, No. 18].

Closest to the technical nature of the claimed composition of the epoxybismaleimide resin selected as a prototype [P. Musto et al. "An Interpenetrated System Based on a Tetrafunctional Epoxy Resin and a Thermosetting Bismaleimide: Structure - Properties Correlation" J. Appl. Pol. Sci., Vol. 69, 1029, (1998), is a known epoxybismaleimide resin composition based on multifunctional:

1) epoxide - N, N, N ′, N′-tetraglycidyl-4,4′-diaminodiphenylmethane (TGDADPM),

2) aromatic bismaleimide - N, N′-diphenylmethanebismaleimide (DFMBMI),

3) hardener - 4,4′-diaminodiphenylsulfone (DADFS).

The disadvantage of the resin composition described in the prototype is the low value of the fracture energy created in the prototype epoxybismaleimide resin: G _1C ≤0.08 KJ / m ² .

An analogue of the claimed method for producing an epoxybismaleimide resin is a method in which the epoxybismaleimide resin is based on 1) polyfunctional epoxides, for example N, N, N ′, N′-tetraglycidyl-diaminodiphenylmethane; 2) an aromatic bismaleimide, for example N, N′-diphenylmethanebismaleimide, 3) a hardener, for example diaminodiphenyl sulfone, is obtained by dissolving all of the above components in a polar organic solvent, for example dimethylformamide, with stirring and heating [US Patent No. 4510272, C08G 59/40; NCI 523/400, 1985].

The disadvantage of the analogue method of producing an epoxybismaleimide resin is the need to remove a relatively high boiling solvent from the binder based on this resin after impregnating it with a reinforcing filler, which makes production more expensive and pollutes the environment. In addition, since it is almost never possible to remove all of the solvent, pores are formed in the process after further impregnation of the thermoforming of the material into the product due to evaporation of residual solvents, which impairs moisture resistance and mechanical characteristics (strength and fracture energy) of composite materials and as a result limits the assortment and service life of products made from them.

The closest in technical essence to the claimed method for producing an epoxybismaleimide resin is a prototype method, comprising mechanically mixing N, N, N ′, N′-tetraglycidyl-diaminodiphenylmethane with 4,4′-diaminodiphenylsulfone, melting the resulting mixture by heating, evacuating the melt with vigorous stirring and subsequent addition to the resulting mixture of N, N′-diphenylmethanebismaleimide, with heating and stirring [P. Musto et al. "An Interpenetrated System Based on a Tetrafunctional Epoxy Resin and a Thermosetting Bismaleimide: Structure - Properties Correlation" J. Appl. Pol. Sci., Vol. 69, 1029, 1998].

The technical task of the invention is to develop both the chemical composition of the epoxybismaleimide resin with increased crack resistance to the level of thermoplastics, and a simple method for its preparation, i.e. obtaining a resin with a fracture energy G _1C in the range of 1 ÷ 3 KJ / m ² without technically complicated operations such as, for example, evacuation.

The essence of the invention and the solution of the technical problem regarding the claimed composition of the epoxybismaleimide binder is a composition containing:

1) polyfunctional epoxides - N, N, N ′, N′-tetraglycidyl-4,4′-diamino-3,3′-dichloro-diphenylmethane (TGDADKHDM, TU 2225-607-11131395-2003) in an amount of 29.2- 47.6 wt.% And triglycidyl paraaminophenol (TGPAF, TU 2225-546-00203521-98) in an amount of 10.9-27.1 wt.%;

2) aliphatic bismaleimide - N, N′-hexamethylene bismaleimide (GMBMI, TU 6-09-07-1593-87) in the amount of 13.9-15.8 wt.%;

3) hardener, aromatic diamine - 4,4′-diaminodiphenylsulfone (DADFS, TU 6-02-1188-79) in an amount of 20.9-30.6 wt.%;

4) the catalyst is N, N′-paraaminophenol (PAF, GOST 5209-07) in an amount of 0.5-2.1 wt.%.

A significant difference between the claimed composition of the epoxybismaleimide binder from the composition of the prototype is the use of a mixture of tetra- and tri-functional epoxides: TGDADCHDFM, TGPAF, as well as a PAF polymerization catalyst that catalyzes both homosopolarization of epoxides with the formation of multifunctional epoxides, their polymerization with DADFPS, and polyp HMBMI followed by copolymerization of a polyaddition adduct with multifunctional epoxides.

The essence of the invention and the solution of the technical problem in terms of the proposed method for producing epoxybismaleimide resin is a method of mixing the components of the resin by heating, characterized in that at first 44.3 g of N, N, N ′ are added to the reactor heated to a temperature of 90 ± 5 ° C, N′-tetraglycidyl-4,4′-diamino-3,3′-dichloro-diphenylmethane, 17.7 g of triglycidyl paraaminophenol and 1.3 g of paraaminophenol preheated to temperatures of 100 ± 5 ° C, 60 ± 5 ° C and 60 ± 5 ° C, respectively. The mixture was stirred for another 17.5 ± 2.5 minutes and then 20.9 g of 4,4′-diaminodiphenylsulfone was added to the resulting mixture for a minimum time sufficient to dissolve it, and the mixture was stirred for 12.5 ± 2.5 minutes, maintaining the temperature mixtures 120 ± 5 ° C. Then, with stirring, the mixture is cooled to a temperature of 100 ± 5 ° C and 15.8 g of N, N′-hexamethylene bismaleimide are added for a minimum time sufficient to dissolve it, followed by stirring of the mixture for 12.5 ± 2.5 minutes, maintaining the temperature mixtures 85 ± 5 ° C.

The resulting epoxybismaleimide resin is poured from the reactor into a container at a temperature of 85 ± 5 ° C. Samples for standard tests before heat treatment at 170 ° C for 2 hours and at 200 ° C for 4 hours

A significant difference between the proposed method for producing epoxybismaleimide resin and the production method described in the prototype is that the prototype for the synthesis of epoxybismaleimide resin uses just one of the well-known multifunctional epoxides, while in the inventive method from a mixture of tetrafunctional (THDFDCHDFM) and trifunctional ( THPAF) of epoxides, when heated by the action of a catalyst (PAF), epoxides are homosopolymerized first and the adduct is more polyfunctional than copolyepoxide, which already further interacts with both aromatic diamine and the product of the addition of aromatic diamine (DADFS) to bismaleimide (HMBMI) to form interpenetrating grafted polymer networks. The result is an epoxybismaleimide multifunctional resin based on multifunctional epoxides, i.e. with functionality much greater than the functionality of each of the original epoxides taken. Since the crack resistance in a series of polyfunctional epoxides is higher, the higher the functionality of epoxy systems [D. Ratna, Handbook of Thermoset Resins, iSmithers. UK, p. 267, 2009], it is potentially possible to obtain a resin with a high fracture energy that is significantly higher in the final mixture than the starting resins based on individual epoxides and bismaleimides taken to obtain an epoxybismaleimide resin.

In addition, in the inventive method, in contrast to the prototype, there are only the simplest technical methods — mixing, heating, and there is no energy- and labor-intensive technological method — evacuation.

The composition and crack resistance of the inventive epoxybismaleimide resin and the resin of the prototype are shown in the table, the production method is described in the example.

Example 1

The method of producing epoxybismaleimide resin

Initially, 44.3 g of N, N, N ′, N′-tetraglycidyl-4,4′-diamino-3,3′-dichlorodiphenylmethane, 17.7 g of triglycidyl paraaminophenol are successively added to the reactor heated to a temperature of 90 ± 5 ° C. and 1.3 g of paraaminophenol preheated to temperatures of 100 ± 5 ° C, 60 ± 5 ° C and 60 ± 5 ° C, respectively. The mixture was stirred for another 17.5 ± 2.5 minutes and only then 20.9 g of 4,4′-diaminodiphenylsulfone was added to the resulting mixture for the minimum time sufficient to dissolve it, and the mixture was stirred for 12.5 ± 2.5 minutes, maintaining mixture temperature 120 ± 5 ° C. Then, with stirring, the mixture is cooled to a temperature of 100 ± 5 ° C and 15.8 g of N, N′-hexamethylene bismaleimide are added for a minimum time sufficient to dissolve it, followed by stirring of the mixture for 12.5 ± 2.5 minutes, maintaining the temperature mixtures in the range of 85 ± 5 ° C.

The resulting epoxybismaleimide resin is poured from the reactor into a container at a temperature of 85 ± 5 ° C. Samples for standard tests are heat treated at 170 ° C for 2 hours and 200 ° C for 4 hours before being tested.

Examples 2-5

All examples are similar to the method for producing resin in example 1, and the ratio of the components in them is examples 2-5 shown in the table.

The table shows that the fracture toughness of the obtained resin is more than an order of magnitude superior to the epoxybismaleimide resin of the prototype, practically maintaining the values of other properties.

Claims (2)

1. The composition of the epoxybismaleimide resin for polymer composite materials containing a polyfunctional epoxy resin, a polymerization catalyst, bismaleimide and hardener 4,4′-diaminodiphenylsulfone, characterized in that the mixture of N, N, N ′, N′-tetraglycidyl is used as a polyfunctional epoxy -4,4′-diamino-3,3′-dichlorodiphenylmethane and triglycidyl paraaminophenol, as a catalyst, paraaminophenol, as bismaleimide, N, N′-hexamethylene bismaleimide in the following ratio, wt.%:
N, N, N ′, N′-tetraglycidyl-4,4′-diamino-3,3′- dichlorodiphenylmethane 29.2-47.6 triglycidyl paraaminophenol 10.9-27.1 paraaminophenol 0.5-2.1 N, N′-hexamethylene bismaleimide 13.9-15.8 4,4′-diaminodiphenylsulfone 20.9-30.6 2. A method of obtaining an epoxybismaleimide resin composition by mixing the components with heating, characterized in that first, N, N, N ′, N′-tetraglycidyl-4,4 ′ are successively added to the reactor heated to a temperature of 90 ± 5 ° C -diamino-3,3′-dichlorodiphenylmethane, triglycidyl paraaminophenol and paraaminophenol, preheated respectively to temperatures of 100 ± 5 ° C, 65 ± 5 ° C and 60 ± 5 ° C, and the resulting mixture is stirred for 17.5 ± 2.5 min at a temperature of 90 ± 5 ° C, then powdered 4,4′-diaminodiphenyl sulfon is added to the resulting mixture n for a minimum time sufficient to dissolve it, the resulting liquid mixture is first stirred for 17.5 ± 2.5 minutes, maintaining the temperature of the mixture 120 ± 5 ° C, then, while continuing stirring, the mixture is cooled to a temperature of 100 ± 5 ° C and powdered N, N′-hexamethylene bismaleimide is added for a minimum time sufficient to dissolve it, followed by stirring of the resulting liquid mixture for 12.5 ± 2.5 minutes and at a temperature of the mixture of 85 ± 5 ° C.