With the improvement of building energy-saving standards, thermal insulation nails have become a key material for green buildings. This article analyzes the core technologies of insulation nails: low thermal conductivity materials (such as nylon and composite materials), bridge breaking structure design, weather resistant coatings, etc.
1〠Material selection: Balance of low thermal conductivity and high strength
Nylon (PA) and composite materials
The thermal conductivity of nylon material is only 0.25 W/(m · K), much lower than that of stainless steel (16 W/(m · K)), which can reduce heat conduction by more than 80%. Reinforced nylon (such as PA66+GF30) enhances its tensile strength to 90MPa through glass fiber, meeting the requirements for external wall anchoring.
Broken bridge stainless steel nail
Adopting a combination design of stainless steel nail body and nylon sleeve, the metal is physically isolated to block direct contact with the wall. For example, a certain brand's broken bridge nail reduces the thermal bridge effect by 60% and has a tensile pull force of 0.8kN, which is suitable for heavy insulation boards such as rock wool.
Ceramic coating technology
Spraying zirconia ceramic layer (with a thermal conductivity of 1.5 W/(m · K)) on the surface of metal nails not only preserves metal strength but also achieves thermal insulation. Experiments have shown that a coating thickness of 0.2mm can reduce the thermal conductivity of the nail body by 40%.
2〠Structural Design: Cracking Heat Conduction from Geometry
Asymmetric nail head
Using umbrella shaped or disc-shaped nail heads to increase the contact area with the insulation board, disperse pressure while reducing the heat flux density per unit area. A certain engineering case shows that the disc-shaped nail head reduces the temperature difference between the contact surfaces by 3 ℃.
Air chamber layer design
Set a circular groove in the middle of the nail rod to form a static air insulation layer. The thermal conductivity of air is only 0.024 W/(m · K), which can effectively block heat transfer. This type of structure reduces single nail heat loss by 15% -20%.
Multi segment combination nail
Like the "metal core+plastic outer layer" dual material nail, the metal core bears the mechanical load, and the outer plastic layer is insulated and conductive. Tests have shown that this type of nail has a shear resistance of 1.2kN and a thermal conductivity controlled within 0.5 W/(m · K).
3〠Application Scenarios and Selection Guidelines
Recommended insulation material types, nail types, key parameter requirements
EPS/XPS board full nylon nail tensile pull force ≥ 0.6kN, length ≥ 100mm
Rock wool board bridge broken stainless steel nail tensile pull force ≥ 1.0kN, with expansion sleeve
The thermal conductivity of the contact surface of the ceramic coating nail on the vacuum insulation board is ≤ 0.8 W/(m · K)
Multi segment composite nails for curtain wall system with shear resistance ≥ 1.5kN, weather resistance temperature -40 ℃~80 ℃
4〠Industry Trends and Technological Innovation
Intelligent temperature control nail
Germany has developed nails with built-in phase change materials (PCM) that automatically absorb heat when the temperature exceeds the set value, suitable for areas with large temperature differences between day and night.
Carbon fiber reinforced nail
Japanese companies have launched carbon fiber composite nails with a thermal conductivity as low as 0.15 W/(m · K) and a tensile strength exceeding 120 MPa, but the cost is three times higher than traditional nails.
3D printing customized nails
For irregular insulation structures, topology optimized nail bodies can be produced through 3D printing, reducing material usage by 20% while ensuring strength.
conclusion
Choosing insulation nails requires comprehensive consideration of thermal conductivity, mechanical properties, and cost. With breakthroughs in new materials and structural design, nails will no longer be the "accomplices" of thermal bridges in the future, but will become the "invisible guardians" of building energy efficiency. In engineering practice, it is recommended to prioritize the use of products certified by GB/T 30595-2014 "Building Insulation Anchor Bolts" to ensure both safety and energy efficiency.
Contact Lanxuan to learn more。