ASTM D 202:2023

1.1 These test methods cover procedures for sampling and testing untreated paper to be used as an electrical insulator or as a constituent of a composite material used for electrical insulating purposes. 1.1.1 Untreated papers are thin, fibrous sheets normally laid down from a water suspension of pulped fibers (usually cellulosic) with or without various amounts of nonfibrous ingredients, and which are calendared, if required, to obtain desired thickness and density. Nevertheless, these test methods are applicable, generally although not invariably, to papers formed by other means, to papers modified (during or after formation) by additions, and to papers given subsequent mechanical treatments such as creping. 1.1.2 As an electrical insulating and dielectric material, paper is considered "untreated" until it is subjected to a manufacturing process such as drying, impregnation, or varnish treatment. 1.1.3 The test methods given herein were developed specifically for papers having a thickness of 0.75 mm (0.030 in.) or less. A number of these test methods are also suitable for use on other materials such as pulps or boards. Refer to Test Methods D3376 or D3394 to determine which tests are applicable to pulps or electrical insulating boards. In the paper industry, some products in thicknesses of less than 0.75 mm are termed "paperboard". Such products are included within the scope of these methods. 1.1.4 These test methods are applicable to flexible fibrous-mat materials formed from suspensions of fiber in fluids other than water. Thicknesses of these mats approach 2 mm, and the fibers contained are possibly natural, synthetic, organic, or inorganic; fillers that are natural, synthetic, organic, or inorganic; and flexible polymeric binder materials. 1.2 The procedures appear in the following sections: Procedure Sections ASTM or TAPPI Reference (Modified) Absorption (Rise of Water) 78 to 83 . . . Acidity-Alkalinity-pH 45 to 54 E70 Air Resistance 98 to 101 D726 Aqueous Extract Conductivity 55 to 64 . . . Ash Content 40 to 44 D586 Bursting Strength 102 to 107 D774/D774M Chlorides (Water-Extractable) 165 to 183 . . . Conditioning 15 D6054 Conducting Paths 138 to 151 . . . Density, Apparent 29 to 33 . . . Dielectric Strength 152 to 157 D149 Dimensions of Sheet, Rolls and Cores 16 to 24 D374 Dissipation Factor and Permittivity 158 to 164 D150 Edge-Tearing Resistance 126 to 130 D827 Fiber Analysis 74 to 77 D1030 Folding Endurance 108 to 110 T 423 and D2176 Grammage 25 to 28 D646 Permittivity 158 to 164 D150 Heat Stability in Air 131 to 137 D827 Impregnation Time 84 to 91 . . . Internal-Tearing Resistance 121 to 125 D689 or T 414 Moisture Content 34 to 39 D644 and D3277 Particulate Copper 193 to 202 . . . Particulate Iron 184 to 192 . . . Reagents 4 D1193 Reports 14 E29 Sampling 6 to 13 D3636 ...

29.035.10