1、ASTM D4238 90 m 0759530 0060279 7 Is Tb Designation:D 4238-90 AMERICAN SOCIETY FOR TESTINO AND MATERIALS 19i Race St.,Phllrdrlphk,PI.19103 Repiinicd Iiom lho Annual Ed d ASTM Siandrfdr,GOpyibhI M II nH lirlod inlhr cuirrnl combinad Index,w l rppar In Ihr Mrl adilion.Standard Test Method for Electros
2、tatic Propensity of Textiles This sidnddrd is issued under the fixed designation D 4238:the number immediately following the designation indicates the year of original adoption or,in thccdse of revision.the year of last revision.A number in parentheses indicates the year of last reapproval.A supersc
3、ript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope 1.1 This test method covers the determination of the relative electrostatic propensity of fibers,yarns,and fabrics by a corona discharge.This includes the measurement of the maximum charge voltage and the deca
4、y half-life.1.2 This test method is generally not applicable to pile fabrics.1.3 This siundurd mu.v involve huzurdous materials,oper-arions,and eqiiipment.This stundurd does not purport to udclr.e.s.s ull ofthe sufity problems ussocuted with its use.It is ihe re.pon.sibility oJ the iiser of this sta
5、ndard to establish uppr(ipriuie sujkiy und heulth practices and determine the upplicubility oJ regiilutory limitutions prior to use.See Section 7 for additional precautionary information.2.Referenced Documents 2.1 ASTM Stundurds:D 123 Terminology Relating to Textiles D 2257 Test Method for Extractab
6、le Matter in Textiles3 D 2258 Practice for Sampling Yarn for Testing3 D 3333 Practice for Sampling Man-Made Staple Fibers4 2.2 Oilier Dociiments:Method 4046 of Federal Test Method Standard 101B5 NFPA No.56A Standard for the Use of Inhalation Anesthetics6 3.Terminology 3.1 DcJiniiions:3.i.1 elecirost
7、utc decuy ha!Plife n-in texfiles,the time in minutes for the maximum voltage induced on the textile to be reduced to one-half of the maximum voltage by the various decay mechanisms:conduction and ionization of the air.3.1.2 clccrosruiic propensity,n-the capacity of a nonconducting material to acquir
8、e and hold an electrical charge by induction(via corona discharge)or by triboelectric means(rubbing with another material).3.1.3 For definitions of other textile ferms used in this standard,refer to Terminology D 123.4.Summary of Test Method 4.1 A specimen in equilibrium with specified atmospheric c
9、onditions of relative humidity and temperature is induc-tively charged from a corona discharge of a specified voltage and at a specified distance from the specimen.The max-imum voltage developed on the specimen is measured(Method 4046 of Federal Test Std.101B and NFPA 56A Paragraphs 466 on Antistati
10、c Accessories and Testing,and 468 on Textiles).The rate of decay of the charge on the specimen is measured after the charging electrode is dis-charged.4.I.1 In practice,a specimen is clamped to a grounded metal disc which is rotated at 1720 rpm.A metal frame,covering the specimen,exposes an area of
11、32 by 32 mm,Positioned above the path of the rotating sample is a needle electrode to which a direct current potential from+.O-10 kv can be applied.Rotation of the sample beneath a detecting electrode provides a means of measuring the charge on the sample.The output is measured on either an oscillos
12、cope or through a direct current recorder.In either case,the resulting attenuated voltage is proportional to the voltage developed on the specimen and is a measure of the charge which is equal to the product of the capacitance and the voltage.5.Significance and Use 5.1 Test results can be used to pr
13、edict the electrostatic propensity of fibers,yarns,and fabrics.The test method is useful for quality control,research,and characterization of the static propensity of textiles.5.2 This test method for testing for electrostatic propen-sity of textiIes is not recommended for acceptance testing of comm
14、ercial shipments because between-laboratory precision has not been established.In case of dispute,the statistical bias,if any,between the laboratory of the purchaser and the laboratory of the seller should be determined with each comparison being based on the testing of specimens taken from a lot of
15、 material of the type being evaluated so as to be as homogeneous as possible and then randomly assigned in equal numbers to each of the laboratories.This method is under the jurisdiction of ASTM Committee D-13 on Textiles;inci is tlic direct responsibility of Subcommittee D13.58 on Yarn Test Methods
16、.ticncral.Currcnt edition approved Jan.26.1990.Published May 1990.Originally publislicd ils D 4%-X3.Last previous edition D 4238 2 83.l/I/uu/hrJk!/:IsT.f S/r/tdri./.s.vois 07.01 and 07.02.:i/uf/d H O O q/:l.Sf.if.Y/a/rd&s.Vol 07.0 I.I/I/C/fhJi)k 1 megohm and a sensitivity of 5-10 mV/cm.6.5 Notiitii-ckotiyqiW.such as Triton X-100.6.6 Cliininq solroil,trichlorotrifluoroethane.7.IIatdrdS 7.1 Care must be taken in dealing with the high voltages obtained in this test.It is important that physical con
