RU2465257C1 - Thermoplastic armour compound for charge of solid rocket propellant of ballistite type - Google Patents

Abstract

FIELD: weapons and ammunition.

SUBSTANCE: thermoplastic armour compound contains cellulose ether and plasticiser. Cellulose ether is ethyl cellulose, and plasticiser - dibutylphthalate. Additionally the thermoplastic armour compound contains as a stabiliser of chemical resistance - a synergetic mixture of N-methyl-n-nitroaniline, diphenylamine and 2-nitrodiphenylamine at the ratio of 3:1:1 at the following ratio of components, wt %: ethyl cellulose - 65.0-78.0; dibutylphthalate - 21.0-34.0; synerhetic mixture of N-methyl-n-nitroaniline, diphenylamine and 2-nitrodiphenylamine - 0.5-1.0.

EFFECT: anti-diffusion resistance of an armour coating in respect to propellant nitroesters.

1 cl, 1 tbl, 5 ex

Description

AND

The invention relates to the field of rocket technology, namely to the development of an armor composition for the ballistic type solid rocket fuel (TRT) charge.

Known formulations of armored compounds based on non-combustible cellulose ether-acetyl cellulose: patents RU 2179989 from 02.27.2002, RU 2276174 from 01.19.2005 and RU 2215723 from 01.01.2002. The use of polymers of similar nature (nitrocellulose and cellulose acetate) as a base for fuel and armored coatings facilitates the task of bringing their thermomechanical properties closer, which is very important for reliable charge operation in a wide temperature range. However, a common drawback of these armored compositions is the high sorption ability of charge fuel with respect to nitroplasticizers, which leads to saturation of the armor coating with nitroesters during the production and storage of the charge, and this can lead to burnout of the armor coating and abnormal operation of the rocket engine. Armored personnel according to the patent RU 2215723 of 02/11/2002, IPC C06B 21/00, C06D 5/00 adopted by the authors for the prototype.

The technical task of the invention is the development of a thermoplastic armor based on ethyl cellulose for booking a charge from TPT both by injection molding and by extrusion and winding methods, which have higher anti-diffusion resistance to fuel nitroesters and satisfactory mechanical, adhesive and technological properties.

The technical result of the invention lies in the development of a thermoplastic armor for booking a charge from TRT.

The armor includes, wt.%:

Ethyl cellulose (EC) with the number of ethoxyl groups in the range of 45.3-46.8% and viscosity in alcohol-benzene mixtures in the range of 80.1-120 MPa · s TU 6-55-52-91, product the interaction of cellulose and ethyl chloride, production Khimprom OJSC, Usolye-Sibirsky, Irkutsk Region 65.0-78.0 Dibutyl phthalate (DBF) TU 6-05-5119-82, ester orthophthalic acid and normal butyl alcohol production LLC "Ural Plant of Plasticizers" Nizhny Tagil 21.0-34.0 Synergistic mixture of N-methyl-p-nitroaniline (N-MHA) TU 84-07509103.594-2009 (the product is obtained from acetanilide by nitration and methylation), pilot production FSUE NIIPM, diphenylamine (DFA) GOST 194-80 (product of the interaction of aniline with aniline hydrochloride), Production of Azot JSC, Berezniki, Perm Region and 2-nitrodiphenylamine (2-NDFA) TU 2471-618-07509103-2010 (the product of the interaction of ortho-nitroaniline with bromobenzene), pilot production of FSUE "NIIPM", in the ratio 3: 1: 1 0.5-1.0

Plasticizers are always introduced into the composition of ether-cellulose compositions, which give them plasticity, expand the range of highly elastic state, and improve frost resistance. The best plasticizers for ethyl cellulose are phthalic acid esters, the most widely used of which is dibutyl phthalate. The macromolecules of cellulose ethers are subject to degradation under the influence of heat, oxygen, light, etc., which leads to a decrease in the degree of their polymerization, the release of gaseous products. The resistance of ethyl cellulose to the effects of adverse factors is increased by the introduction of appropriate inhibitors and antioxidants, for example, derivatives of aromatic amines - N-MHA, DFA and 2-NDPA.

The invention is presented in the table and consists in the replacement in the existing armor composition (prototype) of the patent RU 2215723 of ethyl cellulose with ethyl cellulose, which has a significantly lower (4 times) absorption capacity of fuel nitroesters, the introduction of dibutyl phthalate as a plasticizer and synergistic mixture in the armor composition N-methyl-p-nitroaniline, diphenylamine and 2-nitrodiphenylamine in a ratio of 3: 1: 1 as a stabilizer of the chemical resistance of ethyl cellulose.

The claimed limits of the ratios of the components in the formulation of the armored composition were determined experimentally and are optimal, providing satisfactory mechanical, adhesive and technological properties of the armored composition.

Formulations of examples of patentable armored composition with different content of components, their mechanical, adhesive and technological properties are shown in the table. There, for comparison, the corresponding characteristics of the prototype are shown.

The melt flow rate was determined according to GOST 11645-73, it characterizes the rheological properties of the armored composition under the following conditions:

cargo weight - 3.8 kg

capillary diameter - 1.18 mm

test temperature - 175 ° C.

Table Name The value of indicators indicators Prototype Pat. RU 2215723 Example 1 Example 2 Example 3 Example 4 Example 5 Component composition, wt.%: Cellulose ether: Cellulose acetate 56.0 - - - - - Ethyl cellulose - 61.0 65.0 74.0 78.0 83.0 Plasticizer Dibutyl Phthalate - 37.0 34.0 25.5 21.0 16.8 Stabilizer: synergistic mixture of N-MHA, DFA and 2-NDPA in 3: 1: 1 ratio - 2.0 1,0 0.5 1,0 0.2 Melt Flow Index (MFI), g / 10 min 2.0 13,2 6.8 3.0 2,3 1,0 Tensile strength, kgf / cm ² , T = + 20 ° C 160 90 107 123 150 170 Relative elongation,%, T = + 20 ° С 75 49 39 34 thirty 25 The modulus of elasticity at 5% deformation, kgf / cm ² , T = + 20 ° C 1900 1140 1350 1700 1920 2200 The strength of the bond with TRT, kgf / cm ² , T = + 20 ° C 60-70 thirty 62 75 65 - The equilibrium content of nitroesters in the armor,% 126 27 27 29th 28 -

From the data of the table it follows that examples 1, 2 and 3 of the proposed armored composition have the values of mechanical characteristics, as well as the strength of the bond with TRT almost at the same level as the prototype. The armor composition of example 5 with a high content of ethyl cellulose (83%), a low content of dibutyl phthalate (16.8%) and a stabilizer - a synergistic mixture of N-MHA, DFA and 2-NDPA in a ratio of 3: 1: 1 (0.2%) has a low the MFI value is 1.0 g / 10 min and cannot be processed by injection molding and extrusion; example 1, where the content of dibutyl phthalate is higher than the stated limit and is 37%, has a high melt flow rate (PTR - 13.2 g / 10 min) and requires booking at low temperatures, resulting in reduced bond strength of the armor with TPT (up to 30 kgf / cm ² ).

The manufacturing technology of the proposed armored composition consists in drying ethyl cellulose, loading it into the mixer and mixing to loosen for 5-7 minutes. After that, a double mixture of dibutyl phthalate and stabilizer is loaded into the mixer and the mass is additionally mixed for at least 1.5 hours. Then, the prepared armored mass is subjected to double granulation on the screw press to ensure its complete homogenization and plasticization.

The performance of the charge covered by the proposed armored personnel was confirmed by a wide range of laboratory and fire bench tests, including alternating and long-term thermostating in the temperature range of ± 60 ° C at the experimental research plant FGUP NIIPM.

Claims (1)

Thermoplastic armor composition for ballistic type solid rocket fuel charge, including cellulose ether and plasticizer, characterized in that it contains ethyl cellulose as cellulose ether, dibutyl phthalate as a plasticizer and additionally contains a synergistic mixture of N-methyl-p- as a chemical stability stabilizer nitroaniline, diphenylamine and 2-nitrodiphenylamine in a ratio of 3: 1: 1 in the following ratio of components, wt.%:
Ethyl cellulose 65.0-78.0 Dibutyl phthalate 21.0-34.0 A synergistic mixture of N-methyl-p-nitroaniline, diphenylamine and 2-nitrodiphenylamine 0.5-1.0