RU2327718C1 - Epoxy binder for composite materials - Google Patents

Abstract

FIELD: chemistry; production of composite materials.

SUBSTANCE: epoxy binder consists of the following components in the given mass ratios: 100 epoxy diane resin, 60-80 iso-methyltetrahydrophtalic anhydride, 1.0-2.0 hardener. The hardener used is an alkanolamine with general formula

where R= (CH₂)₂, (CH₂)₆; R₂=C₆H₅OCH₂, CH₂=CHCH₂OCH₂, HOCH₂, ClCH₂.

EFFECT: improved operational characteristics of the binder, lower temperature and time of hardening, wide assortment of binders on epoxy resin base.

4 tbl, 9 ex

Description

The invention relates to the field of technology for the production of fast-curing epoxy compositions used as a binder for the production of composite materials, for example structural fiberglass, produced by wet winding or pultruded method. The epoxy composition can be used in electrical, aviation, automotive, aerospace, railway and other industries as an impregnating composition of electrical elements, adhesives, coatings, etc.

The relevance of creating new fast-curing compositions of hot curing is not only to optimize the process of curing, but also in the multifunctional purpose of their constituent components, which simplifies the composition. Thus, for example, the anhydride curing catalyst can simultaneously serve as a binder modifier, chain extender, plasticizer, and the like.

Known epoxy binder, including resin, hardener and accelerator in the following ratio of ingredients (wt.%): Epoxy resin ED-20 - 55%, hardener (isomethyl tetrahydrophthalic anhydride) - 44.8%, accelerator - 0.2%. The cured composition has a low elongation under tension (see V.A. Lapitsky, A.A. Kritsuk, Physico-mechanical properties of epoxy polymers and fiberglass, Kiev, Naukova Dumka, 1986, pp. 30-31, Table 21).

Known epoxy binder for composite materials, including epoxy resin, hardener, accelerator - 2,4,6-tris (dimethylaminomethyl) phenol and a plasticizer, characterized in that it contains isomethyl tetrahydrophthalic anhydride as a hardener and a polyurethane grade plasticizer as a plasticizer ” Plastur RKOF-0203 ". RU 2160752, 7 C08L 63/02, C08K 13/00, C08L 63/02, C08L 75:08, C08K 13/00, C08K 5:09, C08K 5:18, 2000.12.20.

The disadvantage of the composition is the high curing temperature, sweating of the hardener and the fragility of the resulting composition.

The known composition of the fast-curing epoxy binder, including the ED-20 epoxy resin, isomethyl tetrahydrophthalic anhydride hardener (iso-MTHFA), the main catalyst 2,4,6-tris- (dimethylaminomethyl) phenol (UP-606-2) (Ustinova A.M. , Oleinikova E.V., Lipskaya V.A., Belobrov N.S., Vorobev A.N. // Fast-curing epoxy binder. Plastic materials. 1983. 3. P. 34).

The disadvantages of this composition are the low pot life of the binder and its poor processability associated with the presence of a sharp exothermic peak during curing. In addition, the products reinforced with fibrous fillers with a binder according to the prototype have not enough high toughness and increased porosity (and hence, increased water absorption). It is necessary to introduce additional impact modifiers and additives (defoamers) that contribute to the removal of air inclusions, which complicates the composition of the binder.

Closest to the claimed invention is a binder for composite materials based on epoxy resin ED-20, hardener is isomethyl tetrahydrophthalic anhydride and a curing accelerator is triethanolamine, for impregnation of fiberglass roving (RU 2220049, class B32B 17/04, E04C 5/07, publ. 12.27.2003).

The disadvantage of the binder is the high curing temperature, sweating of the hardener and the fragility of the resulting composition.

The task of the invention is the creation of a binder based on an epoxy composition with improved performance.

The technical result is to improve the technological and operational characteristics of the binder, reduce the temperature and curing time, as well as expand the range of binders based on epoxy compositions.

This is achieved by the fact that the epoxy binder for composite materials comprising an epoxy diane resin, isomethyl tetrahydrophthalic anhydride and a curing accelerator according to the invention as a curing accelerator, the binder contains alkanolamines of the general formula (I)

where R ₁ = (CH ₂ ) ₂ , (CH ₂ ) ₆ ; R ₂ = C ₆ H ₅ OCH ₂ , CH ₂ = CHCH ₂ OCH ₂ , HOS ₂ , ClCH ₂ .

In the following ratio of components in parts by weight:

Epoxy Dianova Resin one hundred Isomethyltetrahydrophthalic anhydride 60-80 Curing accelerator 1.0-2.0.

The difference of the claimed epoxy binder for composite materials is the use of alkanolamines not described in the literature as a catalyst.

The curing accelerators (alkanolamines) of the claimed invention are obtained by reacting two molecules of an oxirane-containing compound with aliphatic amines in an aromatic solvent medium. The conditions and method of preparation are given in examples 1, 2 and table 1. Table 2 shows the structural formulas, names, yields, melting points ( _Tm ) and retardation factors (R _f ) of the obtained alkanolamines used as catalysts in the curing of epoxy-anhydride compositions.

For the implementation of the method used epoxy Dianova resin brands ED-20 and ED-16 (GOST 10587-84), isomethyl tetrahydrophthalic anhydride (TU 38 103149-85) and triethanolamine (TU 6-09-2448-91).

Example 1

The curing accelerators of N, N'-di (3-phenoxy-2-hydroxypropyl) ethylenediamine (accelerator II of Table 1) are obtained by reacting 10.67 g (0.175 mol) of ethylenediamine and 52.87 g (0.350 mol) of phenyl glycidyl ether in 10 ml toluene, at a temperature of 50 ° C. The synthesis is carried out with the gradual addition of phenyl glycidyl ether. The completion of the reaction is judged by TLC. The resulting alkanolamine precipitate was filtered off and dried.

Example 2

The curing accelerator of N, N'-di (3-allyloxy-2-hydroxypropyl) ethylenediamine (accelerator IV of Table 1) is obtained by reacting 6.13 g (0.102 mol) of ethylenediamine and 29.30 g (0.257 mol) of allyl glycidyl ether in 15 ml benzene, at a temperature of 40 ° C. The synthesis is carried out with the gradual addition of allyl glycidyl ether. The completion of the reaction is judged by TLC. The resulting precipitate was filtered off and dried.

Similarly get curing accelerators (alkanolamines) III, V-IX. The synthesis conditions are presented in table 1.

Table 1. Accelerator No. Oxyran Compound Aliphatic amine Amine mole Mole Oxy compound Synthesis Conditions Solvent V ml T, ° С t h II Phenyl glycidyl ether Ethylenediamine 0.175 0.350 fifty four toluene 10 III Phenyl glycidyl ether Hexamethylenediamine 0.133 0.266 60 5 benzene 10 IV Allyl glycidyl ether Ethylenediamine 0.102 0.257 40-50 3 benzene fifteen V Allyl glycidyl Hexamethylenediamine 0.104 0.405 fifty four toluene twenty ether VI Epichlorohydrin Ethylenediamine 0,112 0.246 40 four toluene fifteen VII Epichlorohydrin Hexamethylenediamine 0.165 0.351 40-45 6 benzene fifteen VIII Glycidol Ethylenediamine 0,101 0.228 40 four toluene fifteen IX Glycidol Hexamethylenediamine 0.142 0.361 45 5 toluene twenty

The binder composition is prepared by dissolving the curing accelerators in the calculated amount of hardener and then mixing with epoxy Dianova resin. The mixture is stirred for 15 minutes, after which it is poured into fluoroplastic forms and cured at 100-110 ° C for 4-6 hours. Table 3 shows the options for the compositions of the proposed binders and their properties.

The properties of the obtained compositions for the binder before and after heat treatment were characterized using standard or generally accepted methods. Viability was determined as the expiration time in a standard device B3-1 of a freshly prepared composition and after storage for 6 hours at 25 ° C (GOST 8420-57). Destructive stress (σ), deformation at failure (σ) and modulus (E) under uniaxial tension and compression were determined, respectively, according to GOST 11262-76, 4648-71 and 4651-68 using a universal testing machine P-0.5. Impact strength was evaluated according to GOST 19109-73 on BKM-5. Table 4 shows the results of comparative tests of epoxy compositions with the addition of active curing accelerators.

Thus, as can be seen from examples of specific performance, this invention allows to obtain an epoxy binder for composite materials with improved technological and operational characteristics, low temperature and curing time, and also allows you to expand the range of binder based on epoxy compositions.

table 2 Connection No Curing accelerators Title Exit, % T _pl. , ° C R _f * (system) ¹ II

N, N'-di (3-phenoxy-2-hydroxy-propyl) ethylenediamine 71.5 171-3 0.32 (A) III

1,6-N, N'-di (3-phenoxy-2-hydroxy-propyl) hexamethylenediamine 68.3 131-4 0.45 (B) IV

N, N'-di (3-allyloxy-2-hydroxy-propyl) ethylenediamine 71.9 85 0.22 (A) 0.16 (B) V

1,6-N, N'-di (3-allyloxy-2-hydroxy-propyl) hexamethylenediamine 78.3 65-66 0.74 (A) 0.49 (B) VI

N, N'-di (3-chloro-2-hydroxy-propyl) ethylenediamine 45,2 135-6 0.45 (A) VII

1,6-N, N'-di (3-chloro-2-hydroxy-propyl) hexamethylenediamine 43,2 116-7 0.52 (B) VIII

N, N'-di (2,3-dihydroxy-propyl) ethylenediamine 43,2 104-5 0.21 (A) IX

1,6-N, N'-di (2,3-dihydroxy-propyl) hexamethylenediamine 39.6 114-5 0.26 (A) X N (CH ₂ CH ₂ CH ₂ OH) ₃ Triethanolamine - - - * - eluent: A - ethyl alcohol. B - isopropyl alcohol: benzene (1: 2).

Table 3 Example No. The ratio of the components of the binder, parts by weight Vitality, h Curing temperature, ° С Curing Duration, τ ED-20 one hundred one iso-MTHFA 60 8 110 four Modifier II 1,5 ED-20 one hundred 2 iso-MTHFA 80 8 110 four Modifier III 1,0 ED-20 one hundred 3 iso-MTHFA 75 6 one hundred four Modifier IV 1,2 ED-20 one hundred four iso-MTHFA 60 6 one hundred four V modifier 2.0 ED-20 one hundred 5 iso-MTHFA 70 6 one hundred four Modifier VI 1,2 ED-20 one hundred 6 iso-MTHFA 60 6 110 four Modifier VII 1,6 ED-20 one hundred 7 iso-MTHFA 75 four one hundred 5 Modifier VIII 1,0 ED-20 one hundred 8 iso-MTHFA 60 four one hundred 5 Modifier IX 2.0 Composition 1 of the prototype: ED-20 one hundred 9 iso-MTHFA 75 four 140 6 Triethanolamine 0.05

Table 4 Example No. Stress under uniform tension, MPa (n / mm ² ) Stress under uniform compression, MPa Relative extension, % Modulus of elasticity, MPa Impact strength, kJ / m ² Gel fraction (degree of polymerization),% Example 1 55,2 136 15.6 308 3,5 95.2 Example 2 33.8 127 22.3 150 3.3 93.5 Example 3 56.2 146 16.3 290 3.4 96.1 Example 4 43.5 131 23.1 143 3.3 93.8 Example 5 55.9 140 15.7 300 3.9 95.8 Example 6 34.8 130 22.4 140 3.2 93.7 Example 7 57.8 164 26.3 230 4.9 97.9 Example 8 49.7 151 31.3 195 4.6 95.6 Prototype 30,2 142 3.6 357 3.2 90.8

Claims (1)

An epoxy binder for composite materials, including epoxy diane resin, isomethyl tetrahydrophthalic anhydride, a curing accelerator, characterized in that the composition contains an alkanolamine of the general formula as a curing accelerator

where R ₁ = (CH ₂ ) ₂ , (CH ₂ ) ₆ ; R ₂ = C ₆ H ₅ OCH ₂ , CH ₂ —CHCH ₂ OCH ₂ , HOCH ₂ , ClCH ₂ in the following ratio of components, parts by weight: Epoxy Dianova Resin one hundred Isomethyltetrahydrophthalic anhydride 60-80 Curing accelerator 1.0-2.0