RU2368635C2 - Heat resistant glue composition of cold hardening - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: composition includes the following components, wt parts: epoxy silicon organic resin - 100, mixture of isomers γ and β-aminopropyltrietoxysilane - 30-45, tris -[2,4,6-(dimethylaminomethyl) phenol] - 1-3, product of interaction of bis-o-cianamines with tetranitrils of aromatic tetracarbon acids -120-160.

EFFECT: produced glue composition has high strength in process of glue joints shift at high temperatures 300°-450°C, with preservation of initial strength of glue joints.

1 cl, 2 tbl, 1 ex

Description

The invention relates to the field of heat-resistant adhesive compositions of cold curing, with increased strength of adhesive joints at temperatures from 300 to 450 ° C and intended for use in aerospace products and other industries.

Known adhesive composition of cold curing, including an epoxy base (a mixture of epoxy resins) and a hardener based on oligoimide (the product of the polycondensation of dimerized methyl esters of higher unsaturated dicarboxylic acids and polyethylene polyamine) with an elastic additive (low molecular weight butadiene acid and nitrile copolymer of patent acid and nitrile catalyst) 2269560).

A disadvantage of the known cold curing adhesive composition is the limited heat resistance not exceeding 300 ° C.

Known heat-resistant adhesive composition of cold curing, including epoxy resin, hardener in the form of a mixture of polyethylene polyamine, modified 1,2-di (oxymethyl) -orthocarborane and oligoimide and filler carbonyl iron (RF patent No. 2108357).

The disadvantage of this adhesive composition is that it provides heat resistance up to 340-380 ° C and is inoperative at 400 ° C and above. In addition, the composition of this composition as a hardener modifier used acute deficit product - 1,2-di (oxymethyl) -orthocarborane.

The closest analogue adopted for the prototype is a heat-resistant adhesive composition for cold curing of the following composition, parts by weight:

Epoxy silicone resin one hundred Oligomethylphenylcarboransiloxane 20-35 A mixture of isomers of γ- and β-aminopropyltriethoxysilane 30-45 Tris- [2,4,6- (dimethylaminomethyl) phenol] 1.5-2.5 Filler 60-200

(RF patent No. 1818832).

The disadvantage of the heat-resistant adhesive composition of the prototype is the insufficient strength of the adhesive joints at temperatures of 300-450 ° C.

An object of the invention is to increase the shear strength of adhesive joints at temperatures of 300-450 ° C while maintaining the initial strength of adhesive joints at the level of the adhesive composition of the prototype.

The solution to this problem is achieved by the fact that a heat-resistant adhesive composition of cold curing is proposed, including an epoxy silicone resin, a mixture of γ- and β-aminopropyltriethoxysilane isomers and tris- [2,4,6- (dimethylaminomethyl) phenol], which additionally contains a bis-o interaction product -cyanamines with tetranitriles of aromatic tetracarboxylic acids in the following ratio, wt.h .:

Epoxy silicone resin one hundred A mixture of isomers of γ- and β-aminopropyltriethoxysilane 30-45 Tris- [2,4,6- (dimethylaminomethyl) phenol] 1-3 Specified Interaction Product 120-160

The authors found that the introduction of the reaction product of the interaction of bis-o-cyanamines with tetranitriles of aromatic tetracarboxylic acids into the epoxy adhesive composition made it possible to increase the strength of adhesive joints at shear at temperatures of 300-450 ° C while maintaining the initial strength of adhesive joints at the level of the prototype adhesive composition.

Resins, for example, SEDM-1, SEDM-2, SEDM-3, SEDM-4 according to OST 6-06-448-95 with a mass fraction of non-volatile substances (dry residue) of at least 98%, mass fraction of epoxy groups 12-15.5% and mass fraction of silicon 2-5%.

As a hardener in the claimed invention, a mixture of isomers of γ- and β-aminopropyltriethoxysilane isomers of the AGM-9 brand according to TU 6-02-724-73 with a mass fraction of the main substance of at least 90%, a tetraethoxysilane content of not more than 5% and an amino group content of 6.8 is used -7.55 wt.%.

As an accelerator of the curing process, we used the product tris- [2,4,6- (dimethylaminomethyl) phenol] UP-606/2 brand according to TU 6-00209817.035-96 with a mass fraction of the main substance of at least 95.5%.

In the inventive adhesive composition, the product of the interaction of bis-o-cyanamines with tetranitriles of aromatic tetracarboxylic acids according to TU 1-595-12-920-2006 with a particle size of not more than 0.2 mm, a melting point of 150-170 ° C and gelatinization time at 200 ° C 40-60 minutes

The specified interaction product can also be used as a binder for composite materials, while it is cured by a stepwise thermal regime with obligatory final heat treatment at a temperature of 350 ° C. The unexpected effect of the claimed invention lies in the fact that the specified product, used as a component of cold curing glue, provides increased strength of adhesive joints at temperatures of 300-450 ° C without heat treatment.

Examples of implementation

The adhesive compositions of examples 1-4 were prepared by mixing all the components in the specified sequence, mixing the composition after the introduction of each of the components to a homogeneous consistency.

The adhesive compositions according to examples 1-4 were applied to the surface prepared for gluing (glued or sanded and then degreased) with a brush or spatula.

Bonding was carried out at a temperature of (18-25) ° C for 7 days at a specific pressure of (0.15-0.2) MPa.

Strength characteristics of adhesive joints were determined according to GOST 14759-69 on samples made of steel 30KhGSA.

The compositions of the claimed adhesive compositions are shown in table 1, and the properties in table 2.

Table 1 Name of components Composition, parts by weight, by examples Prototype one 2 3 four Modified Epoxy: SEDM-1 one hundred - - - SEDM-2 - one hundred - - SEDM-3 - - one hundred - one hundred SEDM-4 - - - one hundred A mixture of isomers of γ-aminopropyltriethoxysilane and β-aminopropyltriethoxysilane thirty 35 40 45 35 Tris- [2,4,6- (dimethylaminomethyl) phenol] one 1,5 2 3 2.5 The product of the interaction of bis-o-cyanamines with tetranitriles of aromatic tetracarboxylic acids 120 140 150 160 - Electrocorundum - - - - 200

As can be seen from table 2, the proposed heat-resistant adhesive composition in comparison with the composition of the prototype provides an increase in the strength of adhesive joints at a test temperature of 300 ° C by 20-30%, at a test temperature of 350 ° C by 27-76%, at a test temperature of 400 ° C by 43-129%, at a test temperature of 450 ° C by 55-133%. The qualitative and quantitative ratio of the components of the heat-resistant adhesive composition allows to achieve a technical result - increase the shear strength of adhesive joints at temperatures from 300 to 450 ° C while maintaining the initial strength of adhesive joints at the level of the adhesive composition of the prototype. Going beyond the proposed ratio of the components of the heat-resistant adhesive composition reduces the strength of the adhesive joints at a test temperature of 300, 350, 400, 450 ° C.

The introduction of the proposed adhesive composition of 1,2-di (oxymethyl) -m-carborane as a heat stabilizer does not lead to the achievement of a technical result. Embrittlement of the adhesive composition is observed, which leads to a decrease in the strength of adhesive joints at a test temperature of 20, 350, 400, 450 ° C.

The use of the proposed heat-resistant adhesive composition for gluing heat-resistant non-metallic materials, including in aircraft products operating at temperatures up to 450 ° C, will improve the reliability of adhesive joints in the specified range of operating temperatures.

Claims (1)

Heat-resistant adhesive composition of cold curing, including epoxy silicone resin, a mixture of isomers of γ- and β-aminopropyltriethoxysilane and tris- [2,4,6- (dimethylaminomethyl) phenol], characterized in that it additionally contains the product of the interaction of bis-o-cyanamines with tetranitriles aromatic tetracarboxylic acids in the following ratio, wt.h .:
Epoxy silicone resin one hundred A mixture of isomers of γ and β-aminopropyltriethoxysilane 30-45 Tris- [2,4,6- (dimethylaminomethyl) phenol] 1-3 Specified Interaction Product 120-160