Fastener Coating with Composite Fillers for Pull-Out Strength
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Solution Overview
Problem
Existing fasteners, even when coated, often experience reduced durability and increased looseness over time, especially in weather-exposed wooden connections, due to insufficient pull-out values.
Innovation Solution
A fastener coated with a composition containing a polymeric binder and fillers, where the fillers improve the pull-out values by increasing the filler content volume fraction, with spherical or hemispherical fillers enhancing nail performance and fibrous fillers benefiting nail screws.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing coating compositions are used on fasteners, then the fasteners gain some protection and improved initial holding power, but the connections become loose over time and durability is insufficient
Solution Approach 1:
The coating composition uses a composite system combining organic polymers (epoxy resin, polyester resin, or vinyl resin) with inorganic fillers (silica, aluminum oxide, titanium dioxide, zirconium dioxide, or barium sulfate). This composite structure provides both adhesion to the fastener and enhanced mechanical interlocking with the wood, resulting in superior long-term durability and resistance to loosening compared to conventional organic-only coatings.
Solution Approach 2:
The invention modifies the chemical and physical parameters of the coating by incorporating inorganic fillers with specific particle sizes (0.1-2.0 μm average diameter) and shapes (spherical, hemispherical, or irregular). These parameter changes enhance the coating's mechanical properties, including hardness, abrasion resistance, and interlocking capability, which directly improve the fastener's long-term holding power and resistance to connection loosening.
2Strength
If the coating composition contains inorganic fillers, then the pull-out values and durability are significantly improved, but the coating formulation becomes more complex
Solution Approach 1:
The invention optimizes the filler particle size parameter to an average diameter of 0.1-2.0 μm, which balances the competing requirements of achieving high pull-out values through mechanical interlocking while maintaining coating applicability and uniformity. The specific size range ensures adequate surface area for bonding without creating excessive viscosity or application difficulties.
Solution Approach 2:
The coating formulation assigns specific functions to different components: organic polymers provide base adhesion and film formation, while inorganic fillers provide mechanical interlocking and hardness. This functional differentiation allows each component to be optimized independently, simplifying the overall formulation development while achieving superior pull-out values through the synergistic combination.
Data Source
AI summary
Fixing device, preferably a nail, a profiled nail, a nail screw, or a screw, which is at least partially coated with a coating composition containing a polymeric binder and filling bodies, is claimed. An independent claim is also included for the coating composition for the fixing device.