Plastic explosive

Abstract

Plastic explosive comprising - pentaerythritol tetranitrate (PETN) of a first particle size, in which at least 90% by weight have a particle size of ≥ 0.16 mm - pentaerythritol tetranitrate (PETN) of a second particle size, in which at least 96% by weight have a particle size of < 149 µm - polyisobutylene - marking agent.

Description

[0001] 251883WO - September 24, 2025

[0002] Plastic explosive

[0003] Technical field

[0004] The present invention relates to a plastic explosive and a method for its production.

[0005] State of the art

[0006] Explosives are chemical compounds or mixtures that release a large amount of energy in the form of heat, pressure, and gas through a sudden chemical reaction. They are used in various fields, including mining, construction, military applications, and pyrotechnics. Explosives are classified according to their sensitivity and intended use, for example, as initiating explosives, primary explosives, and explosive mixtures.

[0007] PETN (pentaerythritol tetranitrate) is a highly effective explosive belonging to the nitrate ester group. It is characterized by a high detonation velocity (up to approximately 8,400 m / s), high brisance, and relatively low sensitivity to mechanical impacts, but is sensitive to shock and friction. PETN is frequently used as a component of detonators, detonating cords, and as an intensifying charge. PETN is produced by the nitration of pentaerythritol with nitric and sulfuric acids.

[0008] Explosives, or explosive particles such as PETN, are often embedded in a matrix of polymeric binders. This technique improves the mechanical stability, handling safety, and malleability of the explosive. Typical binders include polyurethane, polyvinyl acetate, or other synthetic polymers. The resulting plastic explosives can be molded into any desired shape and exhibit increased resistance to environmental influences. The homogeneous distribution of the explosive within the polymer matrix is ​​crucial for uniform detonation and the performance of the final product. 251883WO - September 24, 2025

[0009] Explosives such as PETN and embedded variants are used in military explosives, industrial blasting operations, ignition systems, detonation cords, explosive devices, and pyrotechnics.

[0010] EP 4 296 253 describes a plastic explosive composition comprising pentaerythritol tetranitrate as a high explosive, at least one insensitive explosive, silicone oil as a plasticizing agent, at least one phlegmatizing agent and a marking agent, and characterized in that it comprises a combination of a) nitroguanidine as an insensitive explosive and b) pentaerythritol tetrastearate as a phlegmatizing agent.

[0011] Many PETN-based plastic explosives have shortcomings in handling and moldability. Although many different plastic explosives are known, there is a need for alternative explosives with improved properties.

[0012] Description of the invention

[0013] The invention aims to provide a method and composition for plastic explosives that overcome at least some disadvantages of the prior art.

[0014] The present invention relates to a plastic explosive comprising pentaerythrityl tetranitrate (PETN) in at least two different particle size fractions, polyisobutylene as a binder and at least one marking agent, wherein the composition serves in particular to achieve improved handling.

[0015] The object of the present invention was to provide a plastic explosive that exhibits both high explosive force and optimized malleability and homogeneity, while simultaneously enabling reliable detection and identification. This object is achieved by a plastic explosive comprising

[0016] - PETN of a first particle size fraction, wherein at least 90 wt% of the PETN particles have a particle size of at least 0.16 mm, 251883WO - 24 September 2025

[0017] - PETN of a second particle size fraction, wherein at least 96 wt% of the PETN particles have a particle size of less than 149 µm,

[0018] - Polyisobutylene,

[0019] - a marking agent.

[0020] The combination of coarse-grained and fine-grained PETN results in a composition that exhibits both increased explosive power and improved homogeneity and processability. The coarse-grained PETN fraction contributes in particular to increased mechanical strength, while the fine-grained PETN fraction ensures a uniform distribution within the matrix. The binder polyisobutylene imparts the necessary plasticity to the explosive and guarantees stable cohesion between the different PETN particle sizes. This results in a flexible, malleable mass that can be adapted to various operating conditions.

[0021] The PETN of the first particle size is selected such that at least 90 wt% cannot pass through a 0.16 mm sieve. On the other hand, the first particle size fraction should not be too large. Preferably, at least 98 wt% should pass through a 0.80 mm sieve. The particle size is therefore predominantly between 0.16 and 0.80 mm.

[0022] The PETN of the second particle size is selected to be finer. At least 96 wt% passes through a US #100 sieve, which corresponds to a particle size < 149 pm.

[0023] The US Sieve Numbers (e.g., #100) indicate how many meshes per inch (2.54 cm) there are along the horizontal or vertical axis. This means that a US #100 sieve has a total of 100 holes per inch, with the diameter of each hole varying with the number (in this case, 0.149 mm).

[0024] Preferably, the particle size of the second PETN particle size is selected such that at least 20 wt% remains on a US #200 sieve. A US #200 sieve has a mesh size of 74 pm. 251883WO - September 24, 2025

[0025] The polyisobutylene serves to make the PETN plastically malleable. It holds the PETN particles together.

[0026] The marking agent serves to detect and identify the explosive, preferably DMNB, more preferably in an amount that ensures reliable analytical or spectroscopic detectability. Alternatively, other marking agents may be used, provided they guarantee comparable detectability.

[0027] In one embodiment, paraffin oil and / or another aliphatic compound miscible with polyisobutylene is additionally included.

[0028] In one embodiment, diethyl terephthalate and / or diethylhexyl phthalate is included.

[0029] One embodiment contains graphite.

[0030] The addition of paraffin oil and / or other aliphatic compounds and / or diethyl terephthalate and / or diethylhexyl phthalate serves to selectively adjust the plastic properties and processability.

[0031] According to a preferred embodiment, the plastic explosive comprises specific proportions of PETN, polyisobutylene, paraffin oil, diethylhexyl phthalate or diethyl phthalate (DEP), and DMNB as a marking agent, wherein the particle size distributions of the PETN and the concentrations of the other components are selected to achieve the desired properties with regard to explosive power, malleability, and detectability.

[0032] The present invention is characterized by the targeted adjustment of the particle size distributions of the PETN, the use of a suitable plasticizing binder and the integration of a marking agent, wherein the resulting composition is optimized in particular with regard to explosive power, malleability, homogeneity and detectability.

[0033] According to a further embodiment, the proportion of pentaerythrityl tetranitrate (PETN) of the first grain size is selected to be in the range of 40 to 60 wt.%, preferably to 54 wt.%, based on the total weight of the plastic explosive. Selecting a proportion of coarse-grained PETN in the aforementioned range can increase the mechanical strength as well as the explosive power of the plastic explosive.

[0034] According to a further embodiment, the proportion of pentaerythrityl tetranitrate (PETN) of the second particle size is preferably in the range of 25 to 35 wt.%, preferably 29 to 33 wt.%, based on the total weight of the plastic explosive. This results in a particularly homogeneous distribution of the explosive particles within the plastic matrix, which is thought to contribute to improved formability and a uniform consistency of the explosive.

[0035] According to a further embodiment of the invention, the composition contains polyisobutylene in an amount of 14 to 20 wt.%, preferably 15 to 18 wt.%, based on the total weight of the composition. It has been found that by selectively adjusting the polyisobutylene content, the plastic properties of the explosive can be influenced, in particular the flexibility and malleability of the mass, thus facilitating adaptation to different operating conditions.

[0036] The choice of polyisobutylene content depends on the other components of the composition, taking into account in particular the proportions of PETN of different particle sizes as well as additional components such as paraffin oil or diethyl terephthalate or diethylhexyl phthalate.

[0037] In a further preferred embodiment, mixtures of different polyisobutylene types can be used to further optimize the properties of the plastic explosive. The specified ranges for the polyisobutylene content are to be understood as preferred embodiments; however, other compositions can also be chosen, provided that the desired properties with regard to plasticity, homogeneity, and processability are achieved. 251883WO - September 24, 2025

[0038] Furthermore, it is possible to vary the polyisobutylene content within the specified range to precisely adjust the consistency and processability of the composition. This adjustment is preferably made taking into account the specific requirements of the respective application.

[0039] According to a preferred embodiment, the composition according to the invention comprises a polyisobutylene which, according to DIN 51562, has a viscosity in the range of 600 to 1500 mm². 2 The viscosity is approximately 1 / s at 100 °C. The use of such a polyisobutylene is particularly advantageous when a targeted adjustment of the explosive's plastic properties is desired. This allows for further optimization of the mass's flexibility and malleability, while simultaneously achieving improved cohesion between the solid and liquid components of the composition. According to DIN 51562, the viscosity is preferably in the range of 700 or 1500 mm². 2 / s at 100 °C

[0040] According to a preferred embodiment, the plastic explosive can comprise a marking agent in an amount of 0.1 to 1.5 wt.%, based on the total weight of the composition. The addition of the marking agent within this range enables reliable detection of the explosive, while the physical and chemical properties of the overall composition remain essentially unaffected.

[0041] The marking agent is preferably selected from the group of known detection agents, in particular 2,3-dimethyl-2,3-dinitrobutane (DMNB), although other substances suitable for detection and mixtures thereof may also be used. The use of a marking agent in the specified quantity range is particularly advantageous when analytical or spectroscopic detection of the explosive is required.

[0042] The selection and dosage of the marking agent is flexible and application-specific, including combinations of different 251883WO - 24 September 2025

[0043] Marking materials may be used, provided this contributes to fulfilling the respective requirements.

[0044] The present invention relates to a composition of a plastic explosive, wherein, according to a preferred embodiment, paraffin oil and / or diethyl terephthalate and / or diethylhexyl phthalate may be present in an amount of 0 to 2% by weight, based on the total weight of the composition. The addition of paraffin oil and / or diethyl terephthalate and / or diethylhexyl phthalate is preferably optional, whereby the plastic properties, such as flexibility and processability of the explosive, can be specifically influenced.

[0045] According to a preferred embodiment, paraffin oil is used as a plasticizer, which gives the mass increased suppleness and reduced brittleness.

[0046] Alternatively or additionally, diethyl terephthalate or diethylhexyl phthalate can be used as a plasticizing component, thereby further modifying the consistency of the explosive. The selection and dosage of these additives are preferably determined based on the desired property profile and the specific application.

[0047] In another embodiment, the addition of paraffin oil, diethyl terephthalate, and diethylhexyl phthalate is completely omitted, resulting in a content of 0 wt.% of these components. Alternatively, a small amount, preferably in the range of 0.5 to 2 wt.%, can be added, thereby achieving a targeted modification of the mechanical properties of the plastic explosive.

[0048] The decision regarding the use of paraffin oil and / or diethyl terephthalate / diethylhexyl phthalate, as well as their respective quantities, is preferably made taking into account the requirements for plasticity, homogeneity, and handling of the composition. Furthermore, it is possible to use these additives in combination, provided this contributes to optimizing the desired properties. 251883WO - September 24, 2025

[0049] In a preferred embodiment of the present invention, the paraffin oil contained in the composition can be selected from SIPTECH type paraffin oils, in particular SIPTECH 8 (SIPOL 8), a white oil with a pour point of -9°C and a kinematic viscosity at 40°C of 8.1 mm. 2 / s. This is a commercially available paraffin oil with a defined composition and suitable viscosity, distinguished in particular by its suitability as a plasticizer or plasticizing component. SIPTECH / SIPOL 8 is preferably used when a targeted adjustment of the plasticity and processability of the plastic explosive is desired. However, other paraffin oils with comparable properties can also be used, preferably those exhibiting the desired effects regarding the flexibility and homogeneity of the mass.

[0050] In further embodiments of the invention, nitroguanidine and / or pentaerythrityl tetrastearate may also be included.

[0051] The present invention further relates to a preferred embodiment of a plastic explosive obtainable by a process comprising the mixing of the components used, for example, pentaerythrityl tetranitrate of different particle sizes, polyisobutylene, optionally paraffin oil, diethyl terephthalate or diethylhexyl phthalate, and at least one marking agent, in the presence of water. The mixing is preferably carried out in an aqueous phase, whereby a particularly homogeneous distribution of the solid and liquid components within the matrix is ​​achieved and dust formation during production can be minimized.

[0052] After the mixing of the starting materials is complete, the resulting mixture is subjected to drying, preferably under reduced pressure, particularly in a vacuum. This drying process removes any residual water, resulting in a plastic, malleable explosive with the desired properties.

[0053] According to a preferred embodiment, vacuum drying is carried out at a minimum pressure of 50 mbar or lower, whereby setting such a low pressure accelerates the removal of water from the mixture and ensures particularly uniform drying. Alternatively, drying can also be carried out at other pressures, provided this appears suitable for the respective composition and application. The choice of the drying method and the specific parameters is preferably made depending on the requirements for residual moisture, homogeneity, and processability of the plastic explosive.

[0054] In a further preferred embodiment, the method comprises the targeted adjustment of the drying parameters, taking into account in particular the residual moisture, the homogeneity of the distribution of the components, and the plastic deformability of the final product. This results in a plastic explosive characterized by a uniform matrix structure and optimal processing properties.

[0055] The present invention also relates to a method for producing a plastic explosive, wherein moist pentaerythrityl tetranitrate (PETN) with a water content of at least 25 wt.% is used. This method comprises the step of mixing moist PETN with a water content of at least 25 wt.% with other components of the plastic explosive, wherein the mixing preferably takes place in a suitable mixing vessel and the water serves as a dispersion medium. This effectively suppresses dust formation during the manufacturing process, thereby making the handling and processing of the explosive safer.

[0056] In a preferred embodiment, further components selected from the group consisting of polyisobutylene, paraffin oil, diethylhexyl phthalate, diethyl terephthalate, graphite and 2,3-dimethyl-2,3-dinitrobutane (DMNB) are added to the moist PETN and mixed together, in particular polyisobutylene.

[0057] Preferably, polyisobutylene acts as a hydrophobic component, facilitating the separation of water from the mixture. The excess water can be removed after mixing by suitable means. 251883WO - 24 September 2025

[0058] Removing moisture is achieved through measures such as decanting. Optionally or additionally, drying under reduced pressure or at increased temperature can be carried out to reduce the residual moisture content to a level suitable for further processing.

[0059] The process enables a uniform distribution of the solid and liquid components within the plastic matrix, with the targeted adjustment of the water content during the mixing process contributing to the optimization of the consistency and homogeneity of the final composition. A water content of at least 25% by weight is chosen for safety and process-related reasons, whereby the water content is preferably reduced after the mixing process to a level that ensures the desired formability and further processing of the explosive.

[0060] According to a preferred embodiment, the selection and combination of the aforementioned components, as well as the precise process control, can be adapted to the desired property profile of the plastic explosive. Furthermore, it is possible to include additional steps for the removal of residual water, whereby drying under reduced pressure or at elevated temperature is particularly suitable for obtaining a product with the desired properties.

[0061] The present invention thus relates to a method for producing a plastic explosive, comprising mixing moist PETN with a water content of at least 25 wt.% and further components, wherein the water serves as a dispersion medium and is removed after the mixing process by decantation and / or drying, so that a plastic, malleable explosive with optimized consistency and homogeneity is obtained.

[0062] Example 1

[0063] Mix while moist:

[0064] - 52% PETN SSE Standard (+ / -) 2% particle size see product data sheet 251883WO - 24 September 2025

[0065] - 31% PETN SSE Class 2 (+ / -) 2% particle size see product data sheet

[0066] - 16.5 polyisobutylene (PIB) Glissopal V1500

[0067] -0.1% DMNB

[0068] The starting materials are mixed together with PIB as a hydrophobic additive in a wet process. During this process, most of the water is displaced and decanted.

[0069] Subsequently, vacuum drying takes place at 50 mbar (5 kPa).

[0070] Example 2

[0071] Mix while moist:

[0072] - 52% PETN SSE Standard (+ / -) 2% particle size see product data sheet

[0073] - 31% PETN SSE Class 2 (+ / -) 2% particle size see product data sheet

[0074] - 16.5 polyisobutylene (PIB) Glissopal V700

[0075] -0.1% DMNB

[0076] - 2% paraffin oil Siptech 8

[0077] Example 3

[0078] Mix while moist:

[0079] - 52% PETN SSE Standard (+ / -) 2% particle size see product data sheet

[0080] - 31% PETN SSE Class 2 (+ / -) 2% particle size see product data sheet

[0081] - 16.5 polyisobutylene (PIB) Glissopal V700

[0082] -0.1% DMNB

[0083] - 2% diethyl terephthalate (DEP)

Claims

251883WO - September 24, 2025 Patent claims 1. Plastic explosive containing - Pentaerythrityl tetranitrate (PETN) of a first particle size in which at least 90 wt% have a particle size > 0.16 mm - Pentaerythrityl tetranitrate (PETN) of a second particle size in which at least 96 wt% have a particle size < 149 pm - Polyisobutylen - Marking agent.

2. Plastic explosive according to claim 1, wherein additionally containing paraffin oil and / or diethyl terephthalate and / or diethylhexyl phthalate.

3. Plastic explosive according to claim 1 or 2, wherein the amount of PETN of the first grain size is 40 to 60 wt.%.

4. Plastic explosive according to any of the preceding claims, wherein the amount of PETN of the second grain size is 25 to 35 wt.%.

5. Plastic explosive according to any of the preceding claims, wherein the amount of polyisobutylene is 14 to 20 wt.%.

6. Plastic explosive according to any of the preceding claims, wherein the amount of marking agent is 0.1 to 1.5 wt.%.

7. Plastic explosive according to any of the preceding claims, wherein the amount of paraffin oil, diethyl terephthalate and diethylhexyl phthalate is 0 to 2 wt. %.

8. Plastic explosive according to any of the preceding claims, wherein the amount of PETN of the first grain size is 50 to 54 wt.%.

9. Plastic explosive according to any of the preceding claims, wherein the amount of PETN of the second grain size is 29 to 33 wt.%.

10. Plastic explosive according to one of the preceding claims, wherein the polyisobutylene is a polyisobutylene having a viscosity of 600 to 1500 mmol / L according to DIN 51562. 2 / s at 100°C. 251883WO - September 24, 2025 11. Plastic explosive according to any of the preceding claims, wherein the marking agent is dimethyldinitrobutane (DMNB).

12. Plastic explosive according to any of the preceding claims, wherein the plastic explosive is obtainable by a process in which the products are mixed in the presence of water and subsequently dried under pressure.

13. Method for producing a plastic explosive comprising the step of mixing moist PETN with a water content of at least 25 wt.% with other components to obtain a moist plastic explosive.

14. The method of claim 13, wherein the further components comprise polyisobutylene and a marking agent.

15. The method of claim 13 or 14 comprising drying the moist plastic explosive to a plastic explosive.