Strength band
vulcanised NR high elasticity; carbon-black filled for tyres
Numbers below are bands used by working engineers, not live quotes. Tensile note: vulcanised NR high elasticity; carbon-black filled for tyres.
Fire performance in this atlas is editorial. Real projects need the assembly report.
Mecânico
Stiffness
Modulus follows chemistry and orientation — not the marketing nickname.
Toughness
Crack growth, not peak stress, retires most real parts.
Fatigue / creep
Cyclic and time-dependent damage dominate certificates issued on static coupons.
Hardness / hand
Indentation, drape or compressive class — whichever the trade actually measures.
Térmico
Conductivity
~0.15 W/m·K — Borracha natural is not a substitute for a dedicated λ layer.
Service temperature
Melting / softening / decomposition band: elastomer; decomposes on heat.
Expansion
Joints and clearances must follow the expansion class of Borracha natural, not of steel-by-habit.
Thermal mass
Density ~0.92 g/cm³ sets how fast a section changes temperature.
Ageing of λ
Foams, VIPs and moist batts drift; quote aged values.
Elétrico
Conductor or dielectric
Borracha natural is generally a dielectric or semiconductor film, not building wire.
Static / EMI
Fillers and moisture change resistivity more than brochures admit.
Standards language
IACS, volume resistivity or dielectric strength — pick the quantity the job uses.
Fogo
Reaction to fire
Typical declared class: combustible; tyres are a fire load. This is not a universal passport.
Resistance vs reaction
Euroclass is reaction. EI/R ratings are assemblies — boards, coats, cavities.
Melt-drip / char
Borracha natural can burn or drip; do not treat it as A1 without a system test.
Smoke / toxicity
CO, HCN, HF or fibres — the species depend on chemistry. Name the test (ISO 5659, EN 45545, NFPA 1971).
If a salesperson quotes a single “safety score”, ask which standard, which thickness, which year.