NOMEX® papers and pressboards
NOMEX® papers and pressboards are made entirely of synthetic aromatic polyamide polymer in two forms:
• Floc: short fibers that provide mechanical strength.
• Fibrids: microscopic filmy particles that provide dielectric strength and act as a binder.
The floc and fibrids are combined to form sheet structures by specialized paper or board-making methods. During each process the fibrids join to form filmy webs between the fibers. In most cases, the paper sheet is then densified – or calendered – at high temperature and pressure to permanently lock the components together and produce a relatively impermeable structure with high levels of electrical and mechanical integrity.
Paper and pressboard are the most widely used forms of NOMEX.® There is an appropriate type and thickness for each electrical insulation application.
NOMEX® papers
TYPE 410
TYPE 411
TYPE 414
TYPE 418
TYPE 419
TYPE E56
NOMEX® pressboards
TYPE 992
TYPE 993
TYPE 994
NOMEX® papers
TYPE 410
is the original form of NOMEX® paper, and is widely used in a majority of electrical equipment applications. It is produced in thicknesses from 0.05 to 0.76 mm (2 to 30 mil) with specific gravities from 0.7 to 1.2. As a calendered product, it has high inherent dielectric strength, mechanical toughness, flexibility and resilience. NOMEX® Type 410 is used in almost every known sheet
insulation application.
TYPE 411
is the uncalendered precursor of NOMEX® Type 410. It is available in thicknesses from 0.13 to 0.58 mm, (5 to 23 mil) with a specific gravity of 0.3 and correspondingly lower electrical and mechanical properties. It is used in applications such as motor phase insulation and transformer coil end filler, where high bulk and conformability are of prime importance along with increased impregnability and saturability.
TYPE 414
is electrically and thermally similar to NOMEX® Type 410, but is calendered under different conditions which produce a strong, but more flexible and conformable sheet with an open surface. It is produced in thicknesses from 0.09 to 0.38 mm (3.4 to 15 mil) with specific gravities from 0.9 to 1.0. It is designed for use as slot insulation in handwound motors, for linear wrapping of wire, and as main insulation of fluid-filled and dry type transformers where conformability and impregnability are required.
TYPE 418
is produced by adding 50 percent mica platelets, intimately blended with the floc and fibrids during papermaking. It is available in thicknesses from 0.08 to 0.36 mm (3 to 14 mil) and is designed for high-voltage applications, including motor conductor and coil wrap, and transformer ground and layer insulation. NOMEX® Type 418 is a calendered product with high inherent dielectric strength (30 to 40 kV/mm) (760 to 1015 V/mil), but can also be readily impregnated with varnishes where this is desirable. NOMEX® Type 418 offers increased voltage endurance when compared to NOMEX® Type 410.
TYPE 419
is the uncalendered precursor of NOMEX® Type 418. It is available in two thicknesses, 0.18 mm (7 mil) and 0.33 mm (13 mil), with a specific gravity of 0.5 for applications where conformance and saturability are required.
TYPE E56
is a medium-density paper (specific gravity 0.7) produced in thicknesses from 0.13 to 0.51 mm (5 to 20 mil). This calendered paper has mechanical and electrical properties intermediate between NOMEX® Type 410 and NOMEX® Type 411. It offers a higher yield and therefore economically a more attractive
solution in applications where it is not critical to use to the full extent the mechanical or electrical properties of NOMEX® Type 410.
NOMEX® pressboards
Increased thickness and rigidity set NOMEX® pressboards apart from the other forms of NOMEX.® They are used for spacers and barriers in transformers, both fluid-filled and dry type, and as end-laminations in motors. This family of products offers a range of mechanical properties which insures design flexibility in a variety of applications.
TYPE 992
is a low-density pressboard produced in two thicknesses (1.6 and 3.2 mm) (63 to 125 mil) with a specific gravity of 0.5. This material’s low density allows easy formation of complex shapes and provides the highest saturability of the pressboard products.
TYPE 993
is a medium-density pressboard produced in thicknesses from 1.0 to 4.0 mm (40 to 160 mil) with specific gravities of 0.7 to 0.9. This material provides a balance of rigidity and conformability along with outstanding saturability and excellent properties in oil.
TYPE 994
is a densified version of NOMEX® Type 993, available in thicknesses from 1.0 to 9.6 mm (40 to 380 mil) with specific gravities from 1.1 to 1.2. It provides superior stability under compressive loads. NOMEX® Type 994 will also absorb oils and other fluids, but not as readily as NOMEX® Types 992 and 993.
