dupont nomex paper type 410

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1 dupont nomex paper type DuPont Nomex paper Type is an insulation paper which offers high inherent dielectric strength, mechanical toughness, flexibility and resilience. Nomex paper Type is the original form of Nomex paper, and is widely used in a majority of electrical equipment applications. Available in thicknesses (5 to.6 mm) ( to mil), Nomex paper Type is used in almost every known electrical sheet insulation application. Electrical Properties The typical electrical property values for Nomex paper Type are shown in Table. The AC Rapid Rise dielectric strength data of Table, representing voltage stress levels, withstood to seconds at a frequency of Hz. These values differ from long-term strength potential. DuPont recommends that continuous stresses in transformers not exceed.6 kv/mm ( V/mil) to help minimize the risk of partial discharges (corona). The full wave impulse dielectric strength data shown in Table are based on multiple sheets. These values are appropriate for the applications which employ these materials in such configurations. Data based on single sheets of material are available upon request. The geometry of the system has an effect on the actual impulse strength values of the material. The dielectric strength data are typical values and not recommended for design purposes. Design values can be supplied upon request. Table Typical Electrical Properties Nominal Thickness (mil) Dielectric strength AC rapid rise (V/mil) (kv/mm) Full wave impulse (V/mil) (kv/mm) 86 6 Dielectric Constant at Hz Dissipation Factor at Hz (x ) ASTM D- using 5 mm ( inches) electrodes, rapid rise; corresponds with IEC - subclause. except for electrode set-up of 5 mm ( inches) ASTM D-6 ASTM D- Please note: The properties in this data sheet are typical or average values and should not be used as specification limits. Unless otherwise noted, all properties were measured in air under standard conditions (in equilibrium at C, 5% relative humidity). Note that, like other products of papermaking technology, Nomex papers have somewhat different properties in the papermaking machine direction () compared to the cross direction (). In some applications it may be necessary to orient the paper in the optimum direction to obtain its maximum potential performance.

2 Temperature has a minor effect on dielectric strength and dielectric constant, as shown in Figure. Variations in frequency up to Hz have essentially no effect on the dielectric constant of DuPont Nomex paper Type. The effects of temperature and frequency on dissipation factor of dry Nomex paper Type.5 mm ( mil) paper are shown in Figure. The Hz dissipation factors of thinner papers are essentially the same as those for.5 mm ( mil) at temperatures up to C. At higher temperatures and frequencies, the thicker papers have somewhat higher dissipation factors than those shown for the.5 mm ( mil). Surface and Volume Resistivities of dry Nomex paper Type.5 mm ( mil) paper are shown in Figure as functions of temperature. The corresponding values for other thicknesses of Nomex paper Type are very similar. Percent of Room Temperature Value Figure. Effect of Temperature on Electrical Properties 8 5 Dielectric constant ( Hz) Dielectric strength 5 5 Dielectric constant ASTM D-; Dielectric strength ASTM D- Figure. Dissipation Factor versus Temperature and Frequency The relatively minor effects of moisture (humidity) on the electrical properties of Nomex paper Type.5 mm ( mil) are shown in Table. Like other organic insulating materials, Nomex paper is gradually eroded under attack by corona discharges. Corona intensity is a function of voltage stress, which, in turn, depends almost entirely on design parameters such as spacing between circuit elements, smooth vs. sharp contours, etc. Although corona does not occur during normal operation of properly designed electrical equipment, any device may be subject to occasional overvoltages which produce brief corona discharges; and it is important that the insulation not fail prematurely under these conditions. The voltage endurance (time to failure under corona attack) of Nomex paper Type is superior to other commonly used organic insulations and even compares favorably with some inorganic compositions, as shown in Figure. These data were obtained in all cases on single layers of.5 mm ( mil) materials at room temperature, 5% relative humidity, and Hz frequency. Times to failure at 5 Hz are approximately 6 times as long as indicated. Volume Resistivity, ohm.cm or Surface resistivity, ohm Figure. Resistivity versus Temperature Surface resistivity Volume resistivity 5 5 ASTM D-5 Dissipation Factor 5 Hz Hz Hz Hz 5 5 ASTM D- Table Humidity Effects on Electrical Properties Relative Humidity, % Oven Dry 5 6 Dielectric Strength (V/mil) (kv/mm) Dielectric Constant at Hz at khz Dissipation Factor at Hz (x ) at Hz (x ) Volume Resistivity, (ohm.cm) x x x ASTM D- using 5 mm ( inches) electrodes, rapid rise; corresponds with IEC - subclause. except for electrode set-up of 5 mm ( inches) ASTM D-6 ASTM D-

3 Mechanical Properties The typical mechanical property values for DuPont Nomex paper Type are shown in Table. The effects of high temperatures on tensile strength and elongation are illustrated in Figure 5. Nomex sheet structures also retain good mechanical properties at very low temperatures. At the boiling point of liquid nitrogen (minus 6 C or K) the tensile strength of Nomex paper Type.5 mm ( mil) paper exceeds its room temperature value by to % (depending on direction), while elongation to break is still greater than % (better than most inorganic materials at room temperature). This allows Nomex paper Type to work well in cryogenic applications. The effects of moisture (humidity) on tensile strength and elongation are shown in Figure 6. Like elongation, the tear strength and toughness of Nomex paper Type are also improved at higher moisture contents. The dimensions of bone-dry DuPont Nomex paper Type exposed to 5% relative humidity conditions will increase at most % in the machine direction and % in the cross direction (due to moisture absorption). This swelling is largely reversible when the paper is redried. The rate of change in dimensions will depend, of course, on paper thickness and configuration (for example, individual sheets versus tightly wound rolls). Variations in environmental humidity will usually produce dimensional changes which will be less than %. Stress in kv/mm Percent of Room Temperature Value Figure. Voltage Endurance of Various Insulating Materials Single Layer 8 Rag paper Polyester (mat/film/mat) % epoxy impregnation Glass/mica splittings/glass (with silicone) Polyester film.. Time, hr, for 5 th of Failures Asbestos paper Figure 5. Effect of Temperature on Mechanical Properties NOMEX paper Type ASTM D-5 Hz Tensile elongation () 8 Tensile strength () ASTM D-88 Table Typical Mechanical Properties Nominal Thickness (mil) Typical Thickness (mil) Test Method.6.8 ASTM D Basis Weight, g/m ASTM D66 Density, g/cc Tensile Strength, N/cm Elongation, % Elmendorf Tear, N Initial Tear Strength, N Shrinkage at C, % Method D; N/cm Data presented for Initial Tear Strength is listed in the direction of the sample per ASTM D-. The tear is degrees to sample direction hence for papers with a higher reported ITR, the paper will be tougher to tear in the cross direction. = machine direction of paper = cross direction of paper ASTM D88 ASTM D88 TAPPI ASTM D

4 Figure 6. Effect of Moisture on Mechanical Properties Figure. Useful Life versus Temperature 6 Percent of Bone-dry Value 8 Tensile elongation () Tensile strength () Aging Time, hr to kv/mm ( V/mil) Dielectric Strength 5 Log time = 86. C Relative Humidity, % ASTM D-88 8 ASTM D- (curved electrodes) However, even small dimensional changes, especially if they are non-uniform, can cause or accentuate non-flatness (sag, puckers, etc.) in the sheet, which can cause problems in critical operations like laminating or creping. Therefore, DuPont Nomex paper intended for these applications should be kept sealed in its protective polyethylene wrapper, to maintain uniform moisture content, until just before use. Thermal Properties The effects of long-time exposure of DuPont Nomex paper Type.5 mm ( mil) to high temperature on important electrical and mechanical properties are shown in figures, 8 and. These Arrhenius plots of aging behavior are the basis for the recognition of Nomex paper as a C insulation by Underwriters Laboratories, the U.S. Navy, and others, and are confirmed by more than years commercial experience. These curves can also be extrapolated to higher temperatures. Measurements show, for example, that Nomex paper Type will maintain kv/mm ( V/mil) dielectric strength for several hours at C, which is the performance predicted by the Arrhenius plot. The thermal conductivity of DuPont Nomex paper Type.5 mm ( mil) paper is shown in Figure. These values are similar to those for cellulosic papers, and, as with most materials, are primarily determined by specific gravity (density). Therefore, thinner grades of Nomex paper Type will have slightly lower conductivity, and thicker grades will have higher conductivities, as is seen in Table. The total system construction may affect the overall thermal conductivity, therefore, care should be taken in applying individual sheet data to actual situations. For example, two sheet insulations with identical thermal conductivities may have quite different effects on heat transfer from a coil, due to the differences in stiffness or winding tension which affect the spacing between the insulation layers. Aging Time, hr to 5% of Initial Strength in Machine Direction Aging Time, hr to 5% of Initial Elongation in Machine Direction Figure 8. Useful Life versus Temperature 6 5 Log time = 6. C + 8 Tested per UL-6 Figure. Useful Life versus Temperature 6 5 Log time =. 85 C + 8 Test per UL 6

5 Chemical Stability The compatibility of DuPont Nomex paper and pressboard with virtually all classes of electrical varnishes and adhesives (polyimides, silicones, epoxies, polyesters, acrylics, phenolics, synthetic rubbers, etc.), as well as other components of electrical equipment, is demonstrated by the many ULrecognized systems comprising Nomex as well as longstanding commercial experience. Nomex papers are also fully compatible (and in commercial use) with transformer fluids (mineral and silicone oils and other synthetics) and with lubricating oils and refrigerants used in hermetic systems. Common industrial solvents (alcohols, ketones, acetone, toluene, xylene) have a slight softening and swelling effect on Nomex paper Type, similar to that of water. These effects are mainly reversible when the solvent is removed. The Limiting Oxygen Index (LOI) of Nomex paper Type at room temperature ranges between and % (depending on thickness and density), and at C, from to 5%. Materials with LOI above.8% (ambient air) will not support combustion. Nomex paper Type must be heated between C and 5 C (again depending on thickness) before its LOI declines below the flammability threshold. The LOI data for Type. mm (5 mil) is shown in Figure. The effect of 6 megarads (6 Mgy) of MeV beta radiation on the mechanical and electrical properties of Nomex paper Type is shown in Table 5. (By comparison, a laminate of polyester film and polyester mat of the same thickness, % epoxy-impregnated, crumbled after 8 megarads, or 8 Mgy). Similar results were obtained on exposure to gamma radiation. The outstanding radiation resistance of Nomex paper has led to its use in critical control equipment for nuclear power installations. Figure. Therma; Conductivity versus Temperature Thermal Conductivity, mwatt/meter K) Table Thermal Conductivity Nominal Thickness (mil) ASTM E-.5.6 Density, g/cc Thermal Conductivity, mwatt/meter K 5 All data taken at C Limiting Oxygen Index, % Figure. Limiting Oxygen Index (LOI) 5 5 ASTM D-86 Table 5 Radiation Resistance to MEV Electrons (Beta Rays) (Mgy) Dose 8 6 Tensile Strength, % of original Elongation, % of original Dielectric Strength, kv/mm 5 Dielectric Constant Hz khz khz Dielectric Factor (x ) Hz khz khz 8 ASTM D-88 ASTM D- with a 6. mm (. inches) diameter electrode ASTM D-

6 UL ratings Table 6 shows the UL ratings for the Type papers. Descriptions of the numerical values for each of the UL ratings are detailed in the DuPont brochure entitled The UL Yellow Card, available from DuPont. Table 6 UL s ASTM D Thickness (mils) ASTM D Thickness UL Flame Class UL6A HWI UL6A HAI UL6B RTI Electrical UL6B RTI Mechanical UL6A HVTR 5 8. V- 5. V-. V-.5 V-. V-.8 V-.5 V-.6 V-. V-.6 V- UL6A CTI To contact us about DuPont Nomex or for global product support, contact us in your region (listed below). USA DuPont Advanced Fibers Systems Customer Inquiry Center 5 Jefferson Davis Highway Richmond, VA Tel: Fax: Keith.W.Dunnavant@dupont.com Canada E. I. DuPont Canada Company Advanced Fibers Systems P.O. Box Streetsville Postal Station Mississauga, Ontario, L5M H Canada Tel: 8.8./5.8.5 Fax: products@can.dupont.com Europe Du Pont International Operations Sàrl P.O. Box 5 CH- le Grand Saconnex Geneva, Switzerland Tel: Fax: info.nomex@che.dupont.com South America DuPont do Brasil S. A. Alameda Itapecuru, 56 Alphaville Barueri São Paulo, Brasil 65-8 Tel: Fax: produtos.brasil@bra.dupont.com nomexpaper.dupont.com Japan DuPont Teijin Advanced Papers (Japan) Limited Sanno Park Tower -, Nagata-cho -chome Chiyoda-ku, Tokyo -6 Japan Tel: Fax: chihiro.kondo@dupont.com Asia Pacific DuPont Teijin Advanced Papers (Asia) Limited 6/F, Tower 6, The Gateway, Canton Road Tsimshatsui, Kowloon Hong Kong Tel: Fax: nomexpaper@hkg.dupont.com Product safety information is available upon request. This information corresponds to our current knowledge on the subject. It is offered solely to provide possible suggestions for your own experimentation. It is not intended, however, to substitute for any testing you may need to conduct to determine for yourself the suitability of our products for your particular purposes. This information may be subject to revision as new knowledge and experience become available. Since we cannot anticipate all variations in actual end-use conditions, DuPont makes no warranties and assumes no liability whatsoever in connection with any use of this information. Nothing in this publication is to be considered as a license to operate under or a recommendation to infringe upon any trademark or patent right. Copyright DuPont. The DuPont Oval Logo, DuPont, The miracles of science, and Nomex are registered trademarks or trademarks of E.I. du Pont de Nemours and Company or its affiliates. All rights reserved. K-6- (8/) Printed in the U.S.A.