GMT

Polyamide or Polypropylene

These glass-mat reinforced PA and PP panels were developed as lightweight substitutes for aluminum, steel, and plywood. GMT materials consist of long fibers and/or endless glass fiber mats manufactured in a proprietary process and impregnated with the polymers in a second process step.

The key to GMT's success lies in this long-fiber technology: Where unreinforced and short-fiber-reinforced thermoplastics become brittle at low temperatures and may shatter upon impact, GMT exhibits extremely high energy absorption before fracture.

Exhibiting outstanding impact resistance and benign crash behavior, GMT is frequently used in the automotive industry where it is pressed on an industrial scale into complex 3D semi-structural components. Because of its low relative density, excellent hardness and rigidity even at low temperatures, resistance to moisture and chemicals, durability, and ease of recycling, GMT is widely favored as an alternative to many industrial materials.

General properties of GMT panels
Criteria
Thickness availability (in panel form)
GMT Composites
2.5 - 5.4 mm (0.098 - 0.213 in.)
Criteria
Thickness tolerance (In 8-ft panel form)
GMT Composites
'+/- 0.2 mm (0.008 in.)
Criteria
Width tolerance (In 8-ft panel form)
GMT Composites
'+/- 1.0 mm (0.04 in.)
Criteria
Length tolerance (In 8-ft panel form)
GMT Composites
'+/- 5.0 mm (0.197 in.)
Criteria
Standard & custom sizes available
GMT Composites
Max. width 1.4 m (4.59 ft)
Criteria
Forming process (if molded part desired)
GMT Composites
Compression molding
Criteria
Custom colors
GMT Composites
Yes
Criteria
Translucent possible
GMT Composites
Yes
Criteria
Water resistant
GMT Composites
Yes
Criteria
Impact resistance (failure mode)
GMT Composites
Very good (ductile; will not crack or splinter)
Criteria
Resistance to rot, corrosion, mildew
GMT Composites
Excellent
Criteria GMT Composites
Thickness availability (in panel form) 2.5 - 5.4 mm (0.098 - 0.213 in.)
Thickness tolerance (In 8-ft panel form) '+/- 0.2 mm (0.008 in.)
Width tolerance (In 8-ft panel form) '+/- 1.0 mm (0.04 in.)
Length tolerance (In 8-ft panel form) '+/- 5.0 mm (0.197 in.)
Standard & custom sizes available Max. width 1.4 m (4.59 ft)
Forming process (if molded part desired) Compression molding
Custom colors Yes
Translucent possible Yes
Water resistant Yes
Impact resistance (failure mode) Very good (ductile; will not crack or splinter)
Resistance to rot, corrosion, mildew Excellent
Mechanical properties of GMT Panels
Criteria
Tensile strength MD*
Test Methods
ISO 527 / PA_098
Values
45 - 140 MPa
Criteria
Tensile modulus MD*
Test Methods
ISO 527 / PA_098
Values
3300 - 8300 MPa
Criteria
Elongation at break MD*
Test Methods
ISO 527 / PA_098
Values
2.0 - 2.7%
Criteria
Impact strength MD* (Charpy 4.0 mm)
Test Methods
ISO 179-12fn / PA_097
Values
40 - 120 kJ/m2
Criteria Test Methods Values
Tensile strength MD* ISO 527 / PA_098 45 - 140 MPa
Tensile modulus MD* ISO 527 / PA_098 3300 - 8300 MPa
Elongation at break MD* ISO 527 / PA_098 2.0 - 2.7%
Impact strength MD* (Charpy 4.0 mm) ISO 179-12fn / PA_097 40 - 120 kJ/m2
*MD = Machine direction
GMT Options
  • Random or endless glass fiber
  • Mineral filled
  • Colors
  • UV-resistance