RU2259381C1 - Glue composition - Google Patents

Abstract

FIELD: rocket engineering and adhesives.

SUBSTANCE: invention provides composition for attaching solid fuel charge to rocket engine body, said composition being constituted by oxidant, fuel, binder based on synthetic rubber plasticized with mineral plasticizer, transformer and vaseline oils, curing additives, and catalysts. More specifically, glue composition contains urethane rubber with intrinsic viscosity [η] = 0.3-1.3 Dl/g and weight percentage of double bonds 0.5-2.5%, curing agent of the type of dinitrile oxides reactive to double bonds, and solid epoxide resin from diphenylolpropane and epychlorhydrin as active filler.

EFFECT: increased resistance to diffusion of oils from fuel and optimized curing regime regarding curing temperature and duration synchronization.

9 tbl, 7 ex

Description

This invention relates to the field of rocket technology and can be used to fasten a solid fuel charge to a rocket engine body.

There are solid rocket fuels with a binder based on synthetic isoprene, butadiene, butyl and other types of rubbers and various vulcanizing agents. The listed rubbers in their state of aggregation are solid or highly viscous and without plasticization (dissolution) cannot be introduced into the binder fuel and processed on existing equipment into the charges of mixed solid rocket fuel (SRTT).

Petroleum products are often used as plasticizers for isoprene, butadiene and butyl rubbers: in particular, transformer and petroleum jelly oils that dissolve these rubbers well, which makes it possible to obtain a liquid-viscous fuel mass suitable for processing into CPTT charges.

To bond charges from such plasticized solid fuels containing 2.5% or more mineral plasticizer, for example, transformer or liquid paraffin, with a rocket engine body, adhesive compositions are required that have little or no swelling in the fuel plasticizer, since such a plasticizer due to the difference in thermodynamic potentials (rocket fuel, adhesive composition and rubber heat-insulating coating of the solid propellant rocket engine) can diffuse from the fuel into the adhesive composition and the rubber heat-insulating coating of Busan degrade the properties of the boundary layers of the fuel, the adhesive composition and the rubber heat-resistant coating or even lead to delamination of these fuel elements SRM.

As the basis of the present invention, we have chosen polyurethane rubbers that do not swell or little swell in plasticizers such as transformer or liquid paraffin and which are widely used in industry.

Such adhesives are solutions of urethane rubber in volatile solvents (ethers or polybutadiene diols and others), also contain vulcanizing and special additives.

An adhesive composition for bonding solid fuel to a rocket engine housing based on epoxidized low molecular weight rubber as a binder was selected as a prototype of the invention. (Application No. 99104209/04 of 03/02/1999, Patent for the invention No. 2155789).

The disadvantages of this adhesive composition is its very high swelling in fuel plasticizers with a binder based on synthetic isoprene, butadiene, butyl rubber and others. Plasticizers in these fuels are most often transformer or liquid paraffin. The equilibrium swelling of the fixing composition based on epoxidized low molecular weight rubber due to diffusion of plasticizers from these fuels is 60 ... 80% at T = 60 ° C, and this leads to a change in ballistic characteristics during charge burning.

An object of the invention is the development of an adhesive composition for bonding a charge of solid fuel to the RD housing, which is resistant to the diffusion of plasticizers such as transformer or paraffin oil from the fuel, and providing the necessary adhesive properties.

The specified technical problem is solved in the adhesive composition for fastening the charge of solid fuel, consisting of: an oxidizing agent (such as ammonium nitrate, etc.); a binder (synthetic isoprene, butadiene, butyl rubber and others), a plasticizer (transformer or liquid paraffin), stabilizers, a combustion rate catalyst, vulcanizing and technological additives.

The claimed adhesive composition contains urethane rubber having double bonds as urethane rubber, with a characteristic viscosity [η] = 0.3 ... 1.3 Dl / g and a mass fraction of double bonds of 0.5 ... 2.5% ; double bond curing agent of the dinitrile oxide class; active filler - solid epoxy resin of diphenylolpropane and epichlorohydrin with a molecular weight of 1100 ... 2800, the content of epoxy groups 3 ... 12%; the solvent is ethyl acetate, in the following ratio of components (parts by weight):

- urethane rubber having double bonds - 10 ... 70 - a binder;

- hardener reacting in double bonds, class of dinitrile oxides - 0.5 ... 5.0;

- solid epoxy resin from diphenylolpropane and epichlorohydrin - 3.0 ... 10.0 - active filler;

- ethyl acetate - 15.0 ... 86.5 - solvent.

The main characteristics of the adhesive composition:

- viscosity on a viscometer VZ-1 or VZ-240 at T = 20 ° C not more than 40 s .;

- viability at room temperature of 15 ... 35 ° C for at least 4 hours;

- the duration of curing in contact with solid fuel depending on the temperature: 60 ° C - 9 ... 12 days, 70 ° C - 7 ... 9 days;

- the adhesive tensile strength with solid fuel with a binder based on synthetic isoprene rubber is not less than 5.0 kgf / cm ² with a fuel strength of 4.9 kgf / cm ² at T = 20 ° C (with fuel-cohesive failure of adhesive samples )

Physico-mechanical properties of the cured adhesive at a test temperature of 20 ° C:

- fracture strength, kgf / cm ² , not less than 8;

- deformation,%, not less than 250;

- modulus of elasticity at 10% deformation, kgf / cm ² , not less than 12.

Example No. 1

To determine the adhesive and physico-mechanical characteristics of the adhesive composition, the adhesive composition of the following formulation was prepared (parts by weight):

- urethane rubber SUREL-9 TU 38.303-04.1-09-95 - 15;

- epoxy resin E-44 TU 6-10-1347-78 - 5.3;

- hardener TON-2 TU 05121441-270-94 (hardener of a class of dinitriloxides, chemical name di-N-oxide-1,3-dinitrile-2,4,6-triethylbenzene) - 0.7;

- ethyl acetate GOST 22300-76 or GOST 8981-78 - 79.

The adhesive composition is applied to a sample imitating the heat-shielding coating of the taxiway case, consisting of calendared rubber duplicated on one side with a nylon elastic fabric (caproresin).

For the manufacture of caproresin plates, nylon elastic fabric art. 56383 TU 17-04-0812-458-94 and rubber grade 51-1615 (based on SKEPT rubber) TU 2512-013-05766882-97.

The glue composition was applied to this sample of caproresin with a size of 240x180 mm in an amount of 15 ... 20 g. The plate with the applied glue composition was kept in a thermostat at Т = 45 ± 5 ° С for 2 hours in order to remove volatile solvent (ethyl acetate). Then, firecrackers with a diameter of 24.4 mm and a thickness of 2.5 mm were cut from caproresin. Firecrackers on the rubber side were glued to metal fungi with TU 15-1070-82 epoxy glue. Fungi were installed in the mold cover of the dash. 51207.00000 and it was filled with liquid-viscous fuel with a binder based on butadiene rubber dissolved in transformer oil, which also contains an oxidizing agent - ammonium perchlorate, fuel, stabilizers, combustion catalysts and processing aids. The curing of adhesive samples (solid fuel and adhesive composition) was carried out according to the following modes:

at 60 ° C for 9 days;

at 70 ° C for 7 days.

Testing of adhesive samples was carried out by the separation method according to GOST 209-85. The results are shown in table 1. Test temperature 20 ° C.

The destruction of adhesive samples is cohesive in fuel.

From the data given in table 1, it follows that when curing adhesive samples obtained using the proposed adhesive composition, adhesive strength at the level of fuel strength is achieved by curing at 60 ° C for 9 days, at 70 ° C - in 7 days.

Physico-mechanical and physico-chemical characteristics of the proposed adhesive composition are given in table 2

From the data given in table 2 it is seen that the tensile strength of the proposed adhesive composition cured according to the above modes is 10-11 kgf / cm ² at T = 20 ° C, which is higher than the fuel strength (5 ... 6 kgf / cm ² ). Those. during testing and operation, the adhesive composition can withstand greater loads than solid fuel.

table 2 Temperature and duration of curing of the adhesive 60 ° C × 9 days 70 ° C × 7 days 1. Physical and mechanical properties (according to GOST 11202-85): - tensile strength, kgf / cm ² ; 10 eleven - strain at break,% 430 450 - modulus of elasticity at 10% eleven thirteen deformation, kgf / cm ² . 2. Swelling in transformer oil,%, according to GOST 9.030-74 0.3 0.2 3. Swelling in liquid paraffin%, according to GOST 9.03 0-74 0.2 0.2 4. Glass transition temperature, ° C -40 -

The adhesive composition is resistant to swelling in transformer and paraffin oils, as the swelling limit is only 0.2 ... 0.3%.

The glass transition temperature of the adhesive is minus 40 ° C, i.e. up to this temperature it is in a highly elastic state.

Example No. 2

To determine the effect of the content of hardener TON-2 in the proposed adhesive composition on the adhesive properties, the following compositions were prepared (parts by weight):

SUREL-9 urethane rubber fifteen epoxy resin E-44 5.3 hardener TON-2 from 0.5 to 5.0 ethyl acetate 79

The manufacture of adhesive samples was carried out according to the description given earlier in example No. 1. We used solid fuel plasticized with transformer oil with a rubber binder SKI-NL "M" (synthetic low-molecular-weight oil-filled injection molded isoprene rubber) TU 38.03.1.031, which also contains an oxidizing agent - ammonium perchlorate, fuel, stabilizers, combustion catalysts and processing aids. The results of determining the adhesive strength are given in table. 3.

Table 3 The content of TON-2, parts by weight 0.5 1,0 1,5 2.0 3.0 4.0 5,0 Adhesive strength, kgf / cm ² 5,0 5.1 5.2 5.1 5.2 5,0 5.1 The nature of the destruction of the samples Cohesive for fuel

The determination of adhesive strength was carried out at T = 20 ° C. From the data of table 3 it follows that in order to obtain maximum adhesive strength, the content in the adhesive composition of the hardener TON-2 should be in the amount of 0.5 ... 5.0 wt.h. Adhesive strength in the reduced range of the content of TON-2 from 0.5 to 5.0 wt.h. changes slightly and is at the level of fuel strength.

Example No. 3

To determine the effect of the content of epoxy resin E-44 in the adhesive composition on the adhesive properties prepared by ordinary mixing of the components at normal temperature, the following compositions (parts by weight):

urethane rubber SUREL-9M TU 2294-009 13175942-2002 fifteen epoxy resin E-44 from 3.0 to 10.0 hardener TON-2 0.7 ethyl acetate 79.

The adhesive compositions were applied to the fungus samples according to Example No. 1, then the adhesive strength to solid fuels with a binder based on butyl rubber dissolved in transformer oil, which also contained an oxidizing agent - ammonium perchlorate, fuel, stabilizers, combustion catalysts and processing aids, was determined. The results are shown in table 4

Table 4 The content of epoxy resin E-44, parts by weight 3.0 4.0 5,0 6.0 7.0 8.0 9.0 10.0 Adhesive strength, kgf / cm ² 4.7 4.9 5,0 5.1 5.2 5.3 5,4 5,4 The nature of the destruction of the samples Cohesive for fuel

From table 4 it follows that the content of epoxy resin E-44 in the adhesive composition in an amount of 3.0 ... 10.0 wt. including provides adhesive strength at the level of fuel strength.

Example No. 4

To determine the effect on the properties of the adhesive composition of the content of double bonds in urethane rubbers SUREL-9 and SUREL-9M (mass fraction of double bonds in rubber SUREL-9 is 0.9 ... 1.6%; mass fraction of double bonds in rubber SUREL-9 9M - 0.5 ... 2.5%) studies were conducted using batches of rubber SUREL containing a different number of double bonds.

The adhesive composition of the following formulation was prepared (parts by weight):

SUREL urethane rubber with a double bond content of 0.5 to 2.5% fifteen; epoxy resin E-44 5.3 hardener TON-2 0.7 ethyl acetate 74

The adhesive composition was prepared and applied to rubber-fabric firecrackers as described in example No. 1. The manufacture of adhesive samples was carried out in the mold of the drawing 51207.00000. The results are presented in table 5

Table 5 Mass fraction of double bonds in rubber SUREL-9M, SUREL-9,% 0.5 1,0 1,5 2.0 2,5 The adhesive strength at separation, kgf / cm ² 4.8 5.1 5.2 5.3 5,4 The nature of the destruction of the samples Cohesive for fuel

To determine the bond strength, we used fuel with a binder based on butadiene rubber dissolved in transformer oil, which also contains an oxidizing agent - ammonium nitrate and other components.

The strength of the cured fuel during the tensile test was - 5.2 kgf / cm ² at T = 20 ° C. The destruction of adhesive samples is cohesive in fuel.

From the data in Table 5 it follows that the adhesive strength of the samples when using SUREL-9 or SUREL-9M urethane rubbers increases with an unsaturation increase from 0.5 to 2.5%.

Physico-mechanical properties of the adhesive composition made on the basis of rubbers SUREL-9 or SUREL-9M with various unsaturation are given in table 6

The curing of the samples was carried out at 60 ° C for 10 days. From the data in Table 6 it follows that in samples of the adhesive composition in which rubbers SUREL-9 or SUREL-9M were used with a mass fraction of double bonds of 0.5 ... 2.5%, which were cured according to the regime of 60 ° C for 10 days with an increase in rubber unsaturation, the tensile strength and elastic modulus increase, and the deformation decreases slightly, but at the same time their values exceed those required for fastening the engine housing with solid fuel, which usually has the following values:

- tensile strength, kgf / cm ² 5 ... 6,5;

- deformation,% 20 ... 80;

- modulus of elasticity at 10% deformation, kgf / cm ² 8 ... 20.

Example No. 5

To determine the effect of the concentration of the adhesive in ethyl acetate on the adhesion characteristics with solid fuel, 10 ... 90% solutions of the adhesive in ethyl acetate were prepared.

The composition of the adhesive composition (parts by weight):

- urethane rubber SUREL-9 - 20;

- epoxy resin E-44 - 5.3;

- hardener TON-2 - 0.7;

- ethyl acetate - from 10 to 90.

The adhesive compositions were applied to the fungus samples according to the method described in example 1.

The adhesion characteristics with solid fuel based on polyisoprene oil-filled rubber SKI-NL "M" are given in table 7

Table 7 The content of ethyl acetate, parts by weight 10 twenty thirty 40 fifty 60 70 80 90 Adhesive strength, kgf / cm ² 4.7 4.8 4.7 5,0 4.9 5.1 4.8 5,0 4.9 The nature of the destruction of the samples Cohesive for fuel

From the table it follows that, regardless of the concentration of the adhesive composition, the adhesive strength with fuel remains almost at the same level.

Example No. 6

The influence of the molecular weight of urethane rubbers SUREL-9 and SUREL-9M on the adhesion strength to solid fuel with a binder based on synthetic isoprene rubber was determined.

The adhesive composition was prepared as follows (wt. Hours)

- urethane rubber SUREL with an intrinsic viscosity in methyl ethyl ketone at 25 ° C of 0.3 ... 1.3 Dl // g - 20;

- epoxy resin E-44 - 5.3;

- hardener TON-2 - 0.7;

ethyl acetate 74.

The adhesive composition was prepared and applied to the fungus samples according to the procedure described in example No. 1. Adhesion characteristics are given in table 8. To determine the bonding strength, we used fuel with a binder based on butyl rubber dissolved in liquid paraffin, which also contains an oxidizing agent - ammonium perchlorate, fuel, stabilizers, combustion catalysts and processing aids.

Table 8 The characteristic viscosity of the rubber in methyl ethyl ketone at 25 ° C, dl / g 0.3 0.6 0.9 1.3 The adhesive strength at separation, kgf / cm ² 4.8 4.9 5,0 5.2 The nature of the destruction of the samples Cohesive for fuel

From the data in Table 8, it follows that with an increase in the molecular weight of the urethane rubbers SUREL-9 and SUREL-9M, there is a slight increase in the adhesive strength of the adhesive joint to solid fuel and thermal protection caproresin.

Example No. 7

The influence of the content of urethane rubber SUREL-9 and SUREL-9M (mass fraction of double bonds 1.5%) on the properties of the adhesive composition is determined.

The adhesive composition of the following formulation was prepared (parts by weight):

- urethane rubber SUREL with the content of double bonds of 1.2 wt.% - from 10 to 70;

- epoxy resin E-44-5.3;

- hardener TON-2 - 0.7;

ethyl acetate 74.

An adhesive composition was prepared and applied to rubber-fabric firecrackers as described in Example 1. Fuel was used based on a binder made of isoprene rubber. The results are presented in table.9.

Table 9 Mass fraction of rubber SUREL in the adhesive composition,%. 10 twenty thirty 40 fifty 60 70 Adhesive strength, kgf / cm ² 5,0 4.9 5.1 5.2 5.2 5.3 5.3 The nature of the destruction of the samples Cohesive for fuel

From the data given in Table 9, it follows that with an increase in the content of SUREL rubber in the adhesive composition, there is a slight increase in the adhesive strength at break with the fuel.

Claims (1)

Adhesive composition for bonding a charge of solid fuel containing an oxidizing agent, fuel, a binder based on synthetic rubber, plasticized with mineral plasticizer - transformer or liquid paraffin, vulcanizing additives and catalysts, with a rocket engine housing containing urethane rubber as a binder, characterized in that it contains urethane rubber having double bonds as urethane rubber with a characteristic viscosity [η] = 0.3 ... 1.3 Dl / g and a mass fraction of double bonds of 0.5 ... 2.5%, about a double bond hardener of the dinitrile oxide class, the active filler is a solid epoxy resin of diphenylolpropane and epichlorohydrin with a molecular weight of 1100 ... 2800 with an epoxy content of 3 ... 12%, the solvent is ethyl acetate in the following ratio, wt.h .: Double Bonded Urethane Rubber 10 ... 70 Reactive hardener double bonds, class dinitriloxides 0.5 ... 5.0 Solid Epoxy Resin diphenylolpropane and epichlorohydrin 3.0 ... 10.0 Ethyl acetate 15.0 ... 86.5