Biodegradable Cartridge Wad Composition for Moisture-Resistant Ballistics
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Solution Overview
Problem
Existing biodegradable cartridge wads face issues with mechanical performance, moisture sensitivity, complex manufacturing processes, and high costs, leading to inconsistent ballistic performance and increased environmental impact.
Innovation Solution
A wad composition comprising polybutylene succinate as the primary polymer and calcium carbonate at a specific mass fraction, allowing for a simplified manufacturing process and improved mechanical performance, while being biodegradable under environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If biodegradable polymers such as PVA or PHA are used to make wads, then the wad becomes biodegradable and environmentally friendly, but the wad becomes water-soluble and sensitive to moisture, altering its properties during storage
Solution Approach 1:
The patent uses a composite material consisting of polybutylene succinate (a biodegradable polyester) combined with calcium carbonate filler. This composite provides both biodegradability and moisture resistance, as the calcium carbonate reinforces the polymer matrix and reduces water solubility while maintaining environmental compatibility.
Solution Approach 2:
The patent modifies the chemical composition parameters by selecting polybutylene succinate with specific molecular weight and crystallinity characteristics, and optimizing the calcium carbonate content and particle size distribution. These parameter changes enable the material to achieve both biodegradability and dimensional stability under storage conditions.
2Object-affected harmful factors
If lactic acid-based polymers are used for wads, then the wad is biodegradable, but the wad is difficult to process using conventional plastics processing methods and breaks easily
Solution Approach 1:
The patent changes the polymer type from lactic acid-based to polybutylene succinate, which has superior processability with conventional injection molding equipment. The patent also optimizes processing parameters such as injection temperature, pressure, and cooling time to achieve complete filling and proper consolidation without degradation.
Solution Approach 2:
The addition of calcium carbonate as a filler serves multiple functions: it reinforces the polymer matrix to prevent breaking, improves dimensional stability, and maintains biodegradability. The composite formulation enables both ease of manufacture and environmental compatibility.
3Reliability
If conventional non-biodegradable materials are used for wads, then the wad ensures consistent ballistic performance and mechanical strength, but the wad does not degrade in the environment and increases environmental impact
Solution Approach 1:
The patent develops a composite material that replicates the mechanical properties of conventional wads. The polybutylene succinate provides the necessary elasticity and strength, while the calcium carbonate filler enhances rigidity and structural integrity. This combination achieves consistent ballistic performance comparable to traditional materials.
Solution Approach 2:
The patent optimizes the molecular weight, crystallinity, and cross-linking density of the polybutylene succinate to match the mechanical properties of conventional wad materials. The calcium carbonate content and particle size are carefully controlled to ensure proper stress distribution and energy transfer during firing.
4Reliability
If biodegradable wads are made with complex multi-step manufacturing processes, then the wad achieves required performance, but the manufacturing time increases and production cost increases
Solution Approach 1:
The patent combines the polymer and filler into a single homogeneous mixture that can be processed in one injection molding cycle. The master batch containing pre-mixed polybutylene succinate and calcium carbonate eliminates the need for separate mixing, molding, and assembly steps, significantly reducing manufacturing time.
Solution Approach 2:
The patent prepares a master batch with pre-mixed polymer and filler, and pre-designed mold cavities, before the actual production run. This preliminary preparation enables continuous high-speed injection molding without interruptions for material mixing or mold changes, maximizing productivity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The wad achieves consistent ballistic performance, reduced manufacturing time, and effective biodegradation, meeting safety standards and environmental sustainability criteria.
Implementation Method 1
Materials are therefore sought that are capable of degrading in the environment under the effect of micro-organisms and/or low temperatures, for example at temperatures lower than or equal to approximately 30°C-40°C
Implementation Method 2
The wad transmits to the projectile(s) the energy induced by the thrust of the combustion gases of the propellant powder. The wad undergoes very high pressure during a shot, for example reaching more than 1000 bars
Data Source
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AI summary
The present invention relates to a wad (30) that is at least partially biodegradable for shot or bullet cartridges (10), made of a single piece of plastic. Said wad (30) comprises one or more polymers, including one or more polybutylene succinate polymers, and calcium carbonate. The mass fraction of said polymer(s) in said wad (30) is greater than or equal to 70%, the mass fraction of calcium carbonate in said wad (30) is greater than or equal to 6.5%, and the polybutylene succinate polymer(s) constitutes the majority by mass in said wad (30).