DuPont Nomex Paper Type 410 - Precision Punch

DuPont Nomex Paper Type 410Technical Data SheetDuPont Nomex paper Type 410 is an insulation paper which offers high inherent dielectricstrength, mechanical toughness, flexibility and resilience. Nomex paper Type 410 is theoriginal form of Nomex paper, and is widely used in a majority of electrical equipmentapplications. Available in 11 thicknesses (0.05 to 0.76 mm) (2 to 30 mil), Nomex paperType 410 is used in almost every known electrical sheet insulation application.Electrical propertiesThe typical electrical property values for Nomex paper Type 410 are shown in Table I. The AC Rapid Rise dielectricstrength data of Table I, representing voltage stress levels, withstood 10 to 20 seconds at a frequency of 60 Hz.These values differ from long-term strength potential. DuPont recommends that continuous stresses in transformersnot exceed 1.6 kV/mm (40 V/mil) to help minimize the risk of partial discharges (corona). The full wave impulse dielectricstrength data shown in Table I are based on multiple sheets. These values are appropriate for the applications whichemploy 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 strengthdata are typical values and not recommended for design purposes. Design values can be supplied upon request.Table I – Typical electrical propertiesNominal Thickness .51240.61290.73300.76Dielectric strengthAC rapid .72.72.93.23.43.73.73.745666777777Full wave impulse2(V/mil)(kV/mm)Dielectric Constant3at 60 HzDissipation Factorat 60 Hz (x 10–3)3ASTM D149 using 50 mm (2 inches) electrodes, rapid rise; corresponds with IEC 60243-1 subclause 9.1 except for electrode set-up of 50 mm (2 inches)ASTM D34263ASTM D15012

Temperature has a minor effect on dielectric strength and dielectric constant, as shown in Figure 1.Variations in frequency up to 104 Hz have essentially no effect on the dielectric constant of Nomex paper Type410. The effects of temperature and frequency on dissipation factor of dry Nomex paper Type 410 — 0.25 mm(10 mil) paper are shown in Figure 2. The 60 Hz dissipation factors of thinner papers are essentiallythe same as those for 0.25 mm (10 mil) at temperatures up to 200 C. At higher temperatures and frequencies,the thicker papers have somewhat higher dissipation factors than those shown for the 0.25 mm (10 mil).Figure 1. Effect of Temperature on Electrical Properties —Nomex paper Type 410—0.25 mm (10 mil)Percent of Room Temperature Value130120Dielectric constant (60 Hz)1101009080Dielectric strength706050403020100050100150Temperature, C200250300Dielectric constant—ASTM D150; Dielectric strength—ASTM D149Figure 2. Dissipation Factor versus Temperature and Frequency —Nomex paper Type 410—0.25 mm (10 mil)0.0560 Hz0.04210 HzDissipation FactorPlease note:The properties in this data sheet aretypical or average values and shouldnot be used as specification limits.Unless otherwise noted, all propertieswere measured in air under “standard”conditions (in equilibrium at 23 C, 50%relative humidity). Note that, like otherproducts of papermaking technology,Nomex papers have somewhatdiffer ent properties in the papermakingmachine direction (MD) comparedto the cross direction (XD). In someapplica tions it may be necessaryto orient the paper in the optimumdirection to obtain its maximumpotential performance.0.03310 Hz0.02410 Hz0.010.00050100150Temperature, C200250300ASTM D150

Like other organic insulating materials, Nomex paper is gradually eroded under attack by coronadischarges. Corona intensity is a function of voltagestress, which, in turn, depends almost entirely ondesign parameters such as spacing between circuitelements, smooth vs. sharp contours, etc. Althoughcorona does not occur during normal operation ofproperly designed electrical equipment, any devicemay be subject to occasional overvoltages whichproduce brief corona discharges; and it is importantthat the insulation not fail prematurely under theseconditions. The voltage endurance (time to failureunder corona attack) of Nomex paper Type 410 issuperior to other commonly used organic insulationsand even compares favorably with some inorganiccompositions, as shown in Figure 4. These datawere obtained in all cases on single layers of 0.25mm (10 mil) materials at room temperature,50% relative humidity, and 360 Hz frequency.Times to failure at 50–60 Hz are approximately 6–7times as long as indicated.191018101710Volume Resistivity, ohm.cm orSurface resistivity, ohm/squareThe relatively minor effects of moisture (humidity)on the electrical properties of Nomex paper Type 410— 0.25 mm (10 mil) are shown in Table II.Figure 3. Resistivity versus Temperature — Nomex paper Type 410—0.25 mm (10 mil)16101510Surface resistivity14101310Volume resistivity121011101010050100150Temperature, C200250300ASTM D257Table II Humidity Effects on Electrical Properties –Nomex paper Type 410 — 0.25 mm (10 mil)Relative Humidity, %Oven Dry509685033.581532.178030.7Dielectric Constant2at 60 Hzat 1 kHz2.52.32.72.63.23.1Dissipation Factor2at 60 Hz (x 10–3)at 1 Hz (x 10–3)61361411256 x 10162 x 10162 x 1014Dielectric Strength1(V/mil)(kV/mm)Volume Resistivity3, (ohm.cm)ASTM D149 using 50 mm (2 inches) electrodes, rapid rise; corresponds with IEC 60243-1 subclause 9.1 except for electrode set-up of 50 mm (2 inches)ASTM D1503ASTM D25712Figure 4. Voltage Endurance of Various Insulating Materials—Single LayerNomex paper Type 410—0.25 mm (10 mil)24Glass/mica splittings/glass(with silicone)20Polyester(mat/film/mat)100% epoxyimpregnation16Stress in kV/mmSurface and Volume Resistivities of dry Nomex paper Type 410 — 0.25 mm (10 mil) paper areshown in Figure 3 as functions of temperature.The corresponding values for other thicknesses ofNomex paper Type 410 are very similar.Polyester filmRag paper12NOMEX paper Type 4108Asbestos paper40.01.1110100Time, hr, for 5th of 10 Failures100010000ASTM D2275 360 Hz

The typical mechanical property values forNomex paper Type 410 are shown in TableIII. The effects of high temperatures ontensile strength and elongation are illustratedin Figure 5. Nomex sheet structures alsoretain good mechanical properties at verylow temperatures. At the boiling point ofliquid nitrogen (minus 196 C or 77K) thetensile strength of Nomex paper Type 410— 0.25 mm (10 mil) paper exceeds its roomtemperature value by 30 to 60% (dependingon direction), while elongation to break is stillgreater than 3% (better than most inorganicmaterials at room temperature). This allowsNomex paper Type 410 to work well incryogenic applications.Figure 5. Effect of Temperature on Mechanical Properties —Nomex paper Type 410—0.25 mm (10 mil)140130Tensile elongation (MD)120Percent of Room Temperature ValueMechanical properties110100908070Tensile strength (MD)6050403020100050100150Temperature, C200250300ASTM D828Table III — Typical Mechanical PropertiesNominal Thickness .51240.61290.73300.76Test MethodTypical Thickness1 .3115.30.3920.40.5224.20.6128.70.7330.60.78ASTM D3744164115174249310395549692846839ASTM 623816592ASTM STM 6.714.324.8N/AN/AN/AN/AN/AN/ATAPPI414Initial Tear Strength2, 233193ASTM D1004Shrinkage at 300 C, 0.00.00.00.00.00.00.0Basic Weight, g/m2Density, g/ccTensile Strength, N/cmMDXDElongation, %Elmendorf Tear, N12Method D; 17 N/cm2Data presented for Initial Tear Strength is listed in the direction of the sample per ASTM D1004.The tear is 90 degrees to sample direction — hence for papers with a higher reported MD ITR, the paper will be tougher to tear in the cross direction.MD machine direction of paperXD cross direction of paper

The dimensions of bone-dry Nomex paper Type410 exposed to 95% relative humidity conditionswill increase at most 1% in the machine directionand 2% in the cross direction (due to moistureabsorption). This swelling is largely reversiblewhen the paper is redried. The rate of changein dimensions will depend, of course, on paperthickness and configuration (for example, individualsheets versus tightly wound rolls). Variationsin environmental humidity will usually producedimensional changes which will be less than 1%.However, even small dimensional changes,especially if they are non-uniform, can cause oraccentuate non-flatness (sag, puckers, etc.) inthe sheet, which can cause problems in criticaloperations like laminating or creping. Therefore,Nomex paper intended for these applications shouldbe kept sealed in its protective polyethylene wrapper,to maintain uniform moisture content,until just before use.Figure 6. Effect of Moisture on Mechanical Propertis —Nomex paper Type 410—0.25 mm (10 mil)140120Tensile elongation (MD)Percent of Bone-dry ValueThe effects of moisture (humidity) on tensilestrength and elongation are shown in Figure 6.Like elongation, the tear strength and toughnessof Nomex paper Type 410 are also improvedat higher moisture contents.10080Tensile strength (MD)60402000102030405060Relative Humidity, %708090100110ASTM D828

The thermal conductivity of Nomex paper Type 410 —0.25 mm (10 mil) paper is shown in Figure 10. Thesevalues are similar to those for cellulosic papers, and,as with most materials, are primarily determined byspecific gravity (density). Therefore, thinner gradesof Nomex paper Type 410, will have slightly lowerconductivity, and thicker grades, will have higherconductivities, as is seen in Table IV. The total systemconstruction may affect the overall thermal conductivity,therefore, care should be taken in applying individualsheet data to actual situations.For example, two sheet insulations with identicalthermal conductivities may have quite different effectson heat transfer from a coil, due to the differences instiffness or winding tension which affect the spacingbetween the insulation layers.Figure 8. Useful Life versus Temperature —Nomex paper Type 410—0.25 mm (10 mil)610Aging Time, hr to 50% of Initial Strengthin Machine DirectionThe effects of long-time exposure of Nomex paperType 410 – 0.25 mm (10 mil) to high temperature onimportant electrical and mechanical properties areshown in figures 7, 8 and 9. These Arrhenius plotsof aging behavior are the basis for the recognition ofNomex paper as a 220 C insulation by UnderwritersLaboratories, the U.S. Navy, and others, and areconfirmed by more than 40 years’ commercialexperience. These curves can also be extrapolatedto higher temperatures. Measurements show, forexample, that Nomex paper Type 410 will maintain 12kV/mm (300 V/mil) dielectric strength for several hoursat 400 C, which is the performance predicted by theArrhenius plot.510410Log time 7461 – 10.40oC 273310210100140180220260300340Temperature, C610510Log time 9851 – 14.97oC 273410310210100140180220260300Temperature, C340380Test per UL746Figure 10. Thermal Conductivity versus Temperature —Nomex paper Type 410—0.25 mm (10 mil)Figure 7. Useful Life versus Temperature —Nomex paper Type 410—0.25 mm (10 mil)2606240220Thermal Conductivity, mWatt/meter K)Aging Time, hr to 12 kV/mm (300 V/mil)Dielectric Strength10510Log time 8262 – 11.44oC 273410310210100140180220Temperature, C260300340380ASTM D1830 (curved electrodes)380Tested per UL746Figure 9. Useful Life versus Temperature —Nomex paper Type 410—0.25 mm (10 mil)Aging Time, hr to 50% of Initial Elongationin Machine DirectionThermal mperature, C250300ASTM E1530