ForMatter/Materials/polymer/Natural Rubber (vulcanized)
mat_natural_rubber

Natural Rubber (vulcanized)

elastomer (natural) · NR, vulcanized natural rubber, polyisoprene, Hevea rubber, latex rubber
mediumlast updated 2026-04-28
metallic 0.00
hue shift +0°

Sap of the Pará rubber tree, tapped, smoked, and cooked with sulfur until it remembers its shape. Stretches and snaps back like nothing else cheap. Tires, erasers, gaskets, the soles of every shoe before the 1980s. Goes off slowly in sunlight; the smell is the breakdown of double bonds.

Cis-1,4-polyisoprene from Hevea brasiliensis, vulcanized with sulfur (Goodyear, 1839) to crosslink the chains. Tensile strength 17–25 MPa, elongation at break 600–900%, Shore A hardness tunable from gum-soft (~30) to ebonite-hard (~95) by sulfur loading. Glass transition ~−70 °C — stays elastic to deep cold. Ozone- and UV-sensitive; antiozonant additives slow but don't stop chain-scission.

mechanical

  • tensile_strength_mpa20
  • elongation_pct750
  • shore_a_hardness_typical50
source: Wikipedia — Natural rubber; Polymer Database

thermal

  • glass_transition_c-70
  • service_max_c80
source: Polymer Database

Sustainability

  • recyclabilitymoderate — crumb-rubber recovery (mostly tires); not truly closed-loop, but the feedstock is renewable
  • biodegradableFalse
  • certificationsFSC for rubber-tree plantations (where applicable)
visual
warm tan to amber when unfilled; carbon-black-filled to the canonical tire black
tactile
grippy, elastic, slightly sticky to clean dry skin
weight perception
light
acoustic
the snap of a rubber band — a sharp, brief slap

PBR starter values

Principled BSDF defaults derived from the sphere matte finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material.

# finish:      matte
albedo        #3a2f28
metallic      0.00
roughness     0.75
ior           1.45
transmission  0.00
clearcoat     0.00
sheen         0.00
anisotropic   0.00
copy as JSON 
{
  "albedo": "#3a2f28",
  "metallic": 0.0,
  "roughness": 0.75,
  "ior": 1.45,
  "transmission": 0.0,
  "clearcoat": 0.0,
  "sheen": 0.0,
  "anisotropic": 0.0
}
Blender 4.x Python 
# Blender 4.x — Principled BSDF
# Natural Rubber (vulcanized) · finish: matte
import bpy
mat = bpy.data.materials.new(name="mat_natural_rubber")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value         = (0.0423, 0.0284, 0.0212, 1.0)
bsdf.inputs["Metallic"].default_value           = 0.000
bsdf.inputs["Roughness"].default_value          = 0.750
bsdf.inputs["IOR"].default_value                = 1.450
bsdf.inputs["Transmission Weight"].default_value = 0.000
bsdf.inputs["Coat Weight"].default_value        = 0.000
bsdf.inputs["Sheen Weight"].default_value       = 0.000
bsdf.inputs["Anisotropic"].default_value        = 0.000
KeyShot Python (lux) 
# KeyShot 11+ — lux Python API, Generic material
# Natural Rubber (vulcanized) · finish: matte
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_natural_rubber", materialType="Generic")
mat.setProperty("diffuse",      (58, 47, 40))   # 8-bit sRGB
mat.setProperty("metallic",     0.000)
mat.setProperty("roughness",    0.750)
mat.setProperty("indexOfRefraction", 1.450)
mat.setProperty("transparency", 0.000)
mat.setProperty("coatingWeight", 0.000)
Substance pbrMetalRough 
{
  "_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
  "_about": "Natural Rubber (vulcanized) \u00b7 finish: matte",
  "baseColor": {
    "r": 0.0423,
    "g": 0.0284,
    "b": 0.0212
  },
  "metallic": 0.0,
  "roughness": 0.75,
  "ior": 1.45,
  "opacity": 1.0,
  "anisotropyLevel": 0.0,
  "_notes": "Channels listed are the standard Substance pbrMetalRough output. Drop into a Uniform Color node per channel, or as the constant input on a layered stack."
}
glTF 2.0 Metallic-Roughness 
{
  "asset": {
    "version": "2.0",
    "generator": "ForMatter"
  },
  "materials": [
    {
      "name": "mat_natural_rubber",
      "pbrMetallicRoughness": {
        "baseColorFactor": [
          0.0423,
          0.0284,
          0.0212,
          1.0
        ],
        "metallicFactor": 0.0,
        "roughnessFactor": 0.75
      },
      "extensions": {
        "KHR_materials_ior": {
          "ior": 1.45
        }
      }
    }
  ]
}
USD Preview Surface 
# USD Preview Surface — UsdShade.MaterialLook prim attributes
# Natural Rubber (vulcanized) · finish: matte
def Material "mat_natural_rubber" {
    token outputs:surface.connect = </mat_natural_rubber/PreviewSurface.outputs:surface>

    def Shader "PreviewSurface" {
        uniform token info:id = "UsdPreviewSurface"
        color3f inputs:diffuseColor = (0.0423, 0.0284, 0.0212)
        float   inputs:metallic     = 0.000
        float   inputs:roughness    = 0.750
        float   inputs:ior          = 1.450
        float   inputs:opacity      = 1.000
        float   inputs:clearcoat    = 0.000
        token   outputs:surface
    }
}
↓ download glTF material
ProcessInjection Molding · Extrusion · Vulcanization (Rubber Curing)
Substitutes
Silicone Rubber (RTV)
Thermoplastic Polyurethane (TPU)

Citations