RU2528257C1 - Pyrotechnic signal composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: pyrotechnic signal composition of red and green lights contains, wt %: magnesium (12-30), strontium nitrate or barium nitrate (37-59), polyvinylchloride (10-20), phenol formaldehyde resin (4-6) and potassium perchlorate (5-17).

EFFECT: invention will make it possible to increase the light intensity and the specific light sum of the flame with provision of sufficiently high purity of the flame colour.

2 tbl

Description

The invention relates to pyrotechnics, and more particularly to pyrotechnic signal compositions of red and green lights, and can be used for the manufacture of signaling means, in particular signal cartridges, as well as fireworks.

The main emitters in the flame during combustion of the known signal compositions of red and green lights are monochlorides of strontium and barium, respectively. These ions are formed during the decomposition of strontium and barium chlorides, which in turn are formed during chemical reactions in the flame of a burning sample of composition. The best source of chlorine for these reactions is hexachlorobenzene containing about 70% chlorine. The red flame is created by the use of strontium in the composition of the compounds, the green flame is created by the use of barium compounds. The compositions mainly use nitrates of these metals.

Among the most effective compositions of green fire is the composition of index 33-01 according to OCT B84-1712-79, which contains barium nitrate, magnesium, hexachlorobenzene and a binder in the formulation. The purity of the color of the flame of composition 33-01 is 68-72%, while ensuring sufficient light intensity and specific light sum of the flame.

One of the best signal compositions of red light index 35-07 according to OST V84-1712-79 contains strontium nitrate, hexachlorobenzene and the same components in the formulation. The purity of the flame color of the composition is 77-81% with a sufficiently high luminous intensity and specific light sum.

Currently, the production of the above compounds is stopped due to the fact that under the UN Convention of 2000 the use of hexachlorobenzene is prohibited for environmental reasons.

In this regard, in some cases, polyvinyl chloride is used as a replacement for hexachlorobenzene (mainly when using fireworks). The emissivity and color purity of the flame of known compositions based on polyvinyl chloride is lower than when used in hexachlorobenzene compositions. In addition, a feature of these compositions is that with increasing light intensity and specific light sum of the flame, with an increase in the content of metallic fuel in the formulation, a decrease in the purity of the color of the flame occurs.

There are signal formulations containing other chlorinating additives in the formulation. For example, in the signal composition of green fire, according to the USSR author's certificate No. 5373005 of December 13, 755 (class C06B 33/14), chlorinated chloroprene is used as a chlorinating additive. Having a high purity of the color of the flame (up to 74-76%), a burning rate of 0.9-1.2 mm / s, the composition has low values of light intensity and specific light sum. Samples with a diameter of ⌀20 mm from this composition provide a light intensity of 700–760 cd and a specific light sum of 210–220 cd · s / g.

The issue of ensuring high luminous intensity without impairing the purity of the color of the flame is solved in the invention according to the patent of the Russian Federation No. 2460711 of March 29, 2011 (class C06B 33/14) by using chlorine paraffin with a molecular weight of 1100 as the chlorine-containing component with the following components in the formulation (in % by mass):

magnesium 15-20 strontium or barium nitrate 54-64 nitrile butadiene powder rubber with size particles 0.4-2.0 mm 10-15

molecular chlorine paraffin

weighing 1100 10-15 technological additive rest

The disadvantages of the described pyrotechnic composition are poor flammability and unstable combustion process with the formation of a large number of condensed combustion products. In addition, samples of extruded compositions containing chloroparaffins in the formulation have low mechanical strength, which does not allow them to be used in products subjected to high overloads - in signal cartridges, shells, and grenade launcher shots.

The number of matching essential features as a prototype of the selected composition containing the following components (in% by weight):

magnesium 13-18 strontium or barium nitrate 50-60 nitrile butadiene rubber 10-12 polyvinyl chloride 5-10 dicyandiamide 3-5 iditol 1-6 methylene chloride or its mixture with acetone, St. one hundred% 90-180

(see. Textbook, author F. P. Madyakin, N. A. Tikhonov, S. F. Tyutyuanik. Signal and firework compositions and products. Publishing house of Kazan Technological University, Kazan, 2005 - 54 sec.) .

The disadvantage of the pyrotechnic composition of the colored light selected as a prototype is the low light intensity - for samples (diameter 019.8) of green light it is 1880-2160 cd, red light is 2200-3000 cd. The use of a significant amount of volatile solvent in the formulation (up to 180% by weight of the composition) significantly increases the complexity of the technological process of preparing the composition. In addition, methylene chloride is a toxic liquid, which limits its use in production.

The technical problem to which the present invention is directed is to create a pyrotechnic signal composition with increased light intensity and specific light sum of the flame while maintaining a sufficiently high purity of the color of the flame, as well as improving the manufacturability of the preparation.

The technical result is achieved by the fact that the known pyrotechnic signal composition containing magnesium, strontium nitrate (in the case of red light) or barium nitrate (in the case of green light), polyvinyl chloride, phenol-formaldehyde resin, according to the invention additionally contains potassium perchlorate in the following ratio of components (in% by weight):

strontium or barium nitrate 37-59 magnesium 12-30 polyvinyl chloride 10-20 phenol formaldehyde resin 4-6 potassium perchlorate 5-17

Distinctive features provided a high luminous intensity and specific light sum of the flame while at the same time high purity of the color of the flame.

The manufacture of the claimed pyrotechnic signal composition occurs according to the following technology:

1. All dry components are loaded into the mixer and mixed until homogeneous (in the mixer 6LS is 5 minutes).

2. Ethyl alcohol is added in an amount of 3-5% (in excess of 100%) by weight of the composition and mixes until uniform (in a 6LS mixer - 5 minutes).

3. The composition is granulated through a mesh No. 1.25-2.

4. The operation of drying - drying until complete removal of alcohol - is at least 2 hours.

Those. the operation of preparing a solution of a binder-phenol-formaldehyde resin is excluded, which increases the manufacturability of the preparation of the composition in comparison with the prototype.

The components of the proposed composition have a wide raw material base and are produced by domestic industry. The inventive pyrotechnic signal composition has chemical resistance and physico-chemical stability.

The low sensitivity of the composition to impact and friction allows you to prepare and mold compositions on existing equipment pyrotechnic subindustry.

The preparation of samples of the compositions was carried out in cardboard shells by the method of press pressing at a pressure of 2250 kgf / cm ² .

Tests of samples with determination of lighting characteristics were carried out in a small model camera according to GOST 2389.

The recipes of the test characteristic compositions and prototypes and their measured technical characteristics are shown in tables 1 and 2.

Table 1. Recipes and lighting characteristics of the claimed compositions and the prototype of the green light. Name of components The content of components,% by weight Test compounds Prototype Composition No. 1 Number 2 Number 3 one 2 3 four 5 Barium nitrate 49 37 59 50-60 Magnesium 21 thirty 12 13-18 Polyvinyl chloride fourteen 10 twenty 5-10 Phenol formaldehyde resin 5 6 four 1-6 Potassium perchlorate eleven 17 5 - Nitrile butadiene rubber - - - 10-12 Dicyandiamide - - - 3-5

continuation of table 1 one 2 3 four 5 Lighting characteristics of pressed samples with a diameter of 019.8 mm. Luminous intensity, cd 3930 7440 2340 1880-2160 The purity of the color of the flame,% 76 75 77 70-75 Burning rate, mm / s 1.8 2,4 1,1 0.7-1.1 Specific light sum, cd · s / g 2680 5360 1420 1640-1970 The tensile strength of the samples is ⌀20 mm and h = 30 mm, (pressed at a pressure of 2250 kgf / cm ² ), tensile under bending, kgf / cm ² 65 70 63 48-55

Table 2. Recipes and lighting characteristics of the claimed compositions and the prototype of the red light. Name of components The content of components,% by weight Test compounds Prototype Composition No. 1 Number 2 Number 3 one 2 3 four 5 Strontium nitrate 49 37 59 50-60 Magnesium 21 thirty 12 13-18 Polyvinyl chloride
Phenol formaldehyde resin fourteen 10 twenty 5-10 5 6 four 1-6 Potassium perchlorate eleven 17 5 - Nitrile butadiene rubber - - - 10-12 Dicyandiamide - - - 3-5 Lighting characteristics of pressed samples with a diameter of ⌀19.8 mm Luminous intensity, cd 5700 10850 4400 2200-3000 The purity of the color of the flame,% 88 88 90 85-87 Burning rate, mm / s 1.47 2.7 1,6 0.7-1.1 Specific light sum, cd · s / g 75010 8300 5690 3300-3900 The tensile strength of the samples is ⌀20 mm and h = 30 mm, (pressed at a pressure of 2250 kgf / cm ² ), tensile under bending, kgf / cm ² 58 62 56 43-49

The experimental data presented in tables 1 and 2 indicate that the developed signal composition of colored fire significantly exceeds the prototype in terms of light intensity and purity of the color of the flame. Also, the samples of the proposed composition have a higher tensile strength in bending than the prototype.

The proposed pyrotechnic composition of red and green lights is intended to replace pyrotechnic compositions in serial signal products containing hexachlorobenzene in the formulation and for use in newly developed signal products requiring compositions with enhanced lighting characteristics.

Claims (1)

Pyrotechnic signal composition containing strontium or barium nitrate, magnesium, polyvinyl chloride and phenol-formaldehyde resin, characterized in that it additionally contains potassium perchlorate, in the following ratio, wt.%:
strontium or barium nitrate 37-59 magnesium 12-30 polyvinyl chloride 10-20 phenol formaldehyde resin 4-6 potassium perchlorate 5-17