1、Designation: D 1894 08Standard Test Method forStatic and Kinetic Coefficients of Friction of Plastic Film andSheeting1This standard is issued under the fixed designation D 1894; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the y
2、ear of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This test method covers deter
3、mination of the coefficientsof starting and sliding friction of plastic film and sheeting whensliding over itself or other substances at specified test condi-tions. The procedure permits the use of a stationary sled witha moving plane, or a moving sled with a stationary plane. Bothprocedures yield t
4、he same coefficients of friction values for agiven sample.NOTE 1For the frictional characteristics of plastic films partiallywrapped around a cylinder, or capstan, see Test Method G 143 under thejurisdiction of ASTM Subcommittee G02.50.1.2 Test data obtained by this test method is relevant andapprop
5、riate for use in engineering design.1.2.1 As an option to this test, coefficient of friction may berun at temperatures other than 23C by heating only the planewhile the sled is at ambient temperature.1.3 The values stated in SI units are to be regarded asstandard. The values given in parentheses are
6、 for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior t
7、o use. For a specificprecautionary statement, see the end of 6.5.NOTE 2This test method is not equivalent to ISO 82951995, andresults cannot be directly compared between the two methods.2. Referenced Documents2.1 ASTM Standards:2D 618 Practice for Conditioning Plastics for TestingD 883 Terminology R
8、elating to PlasticsD 3574 Test Methods for Flexible Cellular MaterialsSlab,Bonded, and Molded Urethane FoamsD 4000 Classification System for Specifying Plastic Mate-rialsE 691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodG 143 Test Method for Measurement
9、 of Web/Roller Fric-tion Characteristics2.2 ISO Standard:ISO 8295199533. Terminology3.1 Definitions:3.1.1 friction, nresistance to relative motion between twobodies in contact.3.1.1.1 coeffcient of frictionthe ratio of the force requiredto move one surface over another to the total force appliednorm
10、al to those surfaces.3.1.1.2 kinetic coeffcient of frictionthe ratio of the forcerequired to move one surface over another to the total forceapplied normal to those surfaces, once that motion is inprogress.3.1.1.3 static coeffcient of frictionthe ratio of the forcerequired to move one surface over a
11、nother to the total forceapplied normal to those surfaces, at the instant motion starts.3.2 Definitions of Terms Specific to This Standard:3.2.1 slipin plastic films, lubricity of two surfaces slidingin contact with each other.4. Significance and Use4.1 Measurements of frictional properties may be m
12、ade on afilm or sheeting specimen when sliding over itself or overanother substance. The coefficients of friction are related to theslip properties of plastic films that are of wide interest inpackaging applications. These methods yield empirical data forcontrol purposes in film production. Correlat
13、ion of test resultswith actual performance can usually be established.4.1.1 This test method includes testing at temperatures otherthan 23C by heating only the plane while the sled is at ambienttemperature.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct
14、 responsibility of Subcommittee D20.19 on Film and Sheeting.Current edition approved Nov. 1, 2008. Published November 2008. Originallyapproved in 1961. Last previous edition approved in 2006 as D 1894 - 06.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer
15、Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036, http:/www.ansi.org.1*A Summary of Changes secti
16、on appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.4.2 Slip properties are generated by additives in someplastic films, for example, polyethylene. These additives havevarying degrees of compatibilit
17、y with the film matrix. Some ofthem bloom, or exude to the surface, lubricating it and makingit more slippery. Because this blooming action may not alwaysbe uniform on all areas of the film surface, values from thesetests may be limited in reproducibility.4.3 The frictional properties of plastic fil
18、m and sheetingmay be dependent on the uniformity of the rate of motionbetween the two surfaces. Care should be exercised to ensurethat the rate of motion of the equipment is as carefullycontrolled as possible.4.4 Data obtained by these procedures may be extremelysensitive to the age of the film or s
19、heet and the condition of thesurfaces. The blooming action of many slip additives istime-dependent. For this reason, it is sometimes meaningless tocompare slip and friction properties of films or sheets producedat different times, unless it is desired to study this effect.4.5 Frictional and slip pro
20、perties of plastic film and sheetingare based on measurements of surface phenomena. Whereproducts have been made by different processes, or even ondifferent machines by the same process, their surfaces may bedependent on the equipment or its running conditions. Suchfactors must be weighed in evaluat
21、ing data from these meth-ods.4.6 The measurement of the static coefficient of friction ishighly dependent on the rate of loading and on the amount ofblocking occurring between the loaded sled and the platformdue to variation in time before motion is initiated.4.7 Care should be exercised to make cer
22、tain that the speedof response of the recorder, either electronic or mechanical, isnot exceeded.4.8 For many materials, there may be a specification thatrequires the use of this test method, but with some proceduralmodifications that take precedence when adhering to thespecification. Therefore, it i
23、s advisable to refer to that materialspecification before using this test method. Table 1 of Classi-fication System D 4000 lists theASTM materials standards thatcurrently exist.5. Apparatus5.1 SledA metal block 63.5-mm (212-in.) square by ap-proximately 6-mm (0.25-in.) thick with a suitable eye scre
24、wfastened in one end. When a flexible film (see 6.2)istobeattached, the block shall be wrapped with a sponge rubber 63.5mm (212 in.) in width and 3.2 mm (18 in.) in thickness. Thefoam shall be flexible, smooth-faced, and have a nominaldensity of 0.25 g/cm3when measured in accordance with theDensity
25、Test of Methods D 3574. The pressure required tocompress the foam 25 % shall be 85 6 15 kPa (12.5 6 2.5 psi).The foam shall also have a high hysteresis when deformed.4,5The rubber shall be wrapped snugly around the sled and heldin place against the bottom and top of the sled with double-faced maskin
26、g tape. When a sheet (see 6.3) is to be attached,double-faced tape shall be used to attach the specimen. Thetotal weight of the (wrapped) sled and specimen shall be 200 65g.NOTE 3Round-robin testing6has shown that the physical propertiesof the backing can drastically affect both the coefficient of f
27、riction andstick-slip behavior of the film.5.2 PlaneA polished plastic, wood, or metal sheet,7ap-proximately 150 by 300 by 1 mm (6 by 12 by 0.040 in.). Asmooth, flat piece of glass may cover the upper surface of theplane. This provides a smooth support for the specimen.5.2.1 When it is desirable to
28、run tests at temperatures above23C, a heating unit shall be provided that is capable ofmaintaining the temperature of the plane within 62C of thedesired temperature. The temperature should be maintainedwithin 62C of the desired temperature over the entire traverseof the sled (that is, over the full
29、surface of the plane).NOTE 4If the equipment has a plane with a heater, a cover may beused to help maintain the temperature of the plane within 62C of thedesired temperature.5.3 Scissors or Cutter, suitable for cutting specimens to thedesired dimensions.5.4 Adhesive Tape, cellophane or pressure-sens
30、itive.5.5 Adhesive Tape, double-faced.5.6 Nylon Monofilament, having a 0.33 6 0.05-mm (0.0136 0.002-in.) diameter and capable of supporting a 3.6-kg (8-lb)load.5.7 Beaded Chain, flexible metal cable, or equivalent,having a spring rate no less than 600 lbs per inch of stretch perinch of length (40 lb
31、s/in. (7000 N/m) for a 15-in. chain) in therange of 50 to 150 g of tension (such as beaded lampswitch pullchain).5.8 Low-Friction PulleysA phenolic type pulley mountedin hardened steel cone bearings on a metal fork. A ball-bearingtype pulley may also be used.5.9 Force-Measuring Device, capable of me
32、asuring thefrictional force to 65 % of its value. A spring gauge8,5(seeNote 5), universal testing machine, or strain gauge may beused.NOTE 5The capacity of the spring gauge (Fig. 1(a and b) needed willdepend upon the range of values to be measured. For most plastic, a 500-gcapacity gauge with 10-g o
33、r smaller subdivisions will be satisfactory. Thisspring will measure coefficients of friction up to and including 2.5.5.10 Supporting BaseA smooth wood or metal baseapproximately 200 by 380 mm (8 by 15 in.) is necessary tosupport the plane. The supporting base may be a simplerectangular box. If a un
34、iversal testing machine is used to pulla moving plane, a supporting base of sufficient structuralstrength and rigidity to maintain a firm position between themoving crosshead and the force-measuring device will benecessary.4The sole source of supply of sheet stock known to the committee at this time
35、is Greene Rubber Co., 59 Broadway, North Haven, CT 06473.5If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.6Support
36、ing data are available from ASTM Headquarters. Request RR: D20-1065.7Acrylic or rigid poly(vinyl chloride) sheeting has been found satisfactory forthis purpose.8The sole source of supply of the Model L-500 known to the committee at thistime is Hunter Spring Co., Lansdale, PA.D18940825.11 Driving or
37、Pulling Device for Sled or PlaneTheplane may be pulled by a driven pair of rubber-coated rolls notless than 200 mm (8 in.) long, capable of maintaining auniform surface speed 150 6 30 mm/min (0.5 6 0.1 ft/min)(Fig. 1(b), by the crosshead of a universal testing machine(Fig. 1(d) (see Note 6), or a wo
38、rm drive driven with asynchronous motor (Fig. 1(e). A constant-speed chain drivesystem has also been found satisfactory (Fig. 1(a). A power-operated source may be used for pulling the sled over thehorizontally-mounted specimen at a uniform speed of 150 630 mm/min (0.5 6 0.1 ft/min). A universal test
39、ing machineequipped with a load cell in its upper crosshead and a constantrate-of-motion lower crosshead has been found satisfactory(see Fig. 1(c).NOTE 6Where the moving crosshead of a universal testing machine isused to pull the moving plane through a pulley system (Fig. 1(d), thestrain gauge load
40、cell, or other load-sensing instrument in the testingmachine, acts as the force-measuring device.6. Test Specimens6.1 The test specimen that is to be attached to the plane shallbe cut approximately 250 mm (10 in.) in the machine directionand 130 mm (5 in.) in the transverse direction when suchextrus
41、ion directions exist and are identifiable.6.2 Afilm specimen that is to be attached to the sled shall becut approximately 120-mm (412-in.) square. Film is defined assheeting having a nominal thickness of not greater than 0.254mm as indicated in Terminology D 883.6.3 A sheeting specimen (greater than
42、 0.254 mm nominalthickness) or another substance that is to be attached to the sledshall be cut 63.5 mm (212 in.) square.6.4 Sheeting specimens shall be flat and free of warpage.Edges of specimens shall be rounded smooth.6.5 Five specimens shall be tested for each sample unlessotherwise specified. (
43、WarningExtreme care is needed inhandling the specimens. Contamination of the test surface byA. Sled H. Constant-speed drive rollsB. Plane I. Nylon monofilamentC. Supporting base J. Low-friction pulleyD. Gauge K. Worm screwE. Spring gauge L. Half nutF. Constant-speed chain drive M. Hysteresis, synchr
44、onous motorG. Constant-speed tensile tester crossheadFIG. 1 Five Methods of Assembly of Apparatus for Determination of Coefficients of Friction of Plastic FilmD1894083dust, lint, finger prints, or any foreign matter may change thesurface characteristics of the specimens.)NOTE 7Plastic films and shee
45、ting may exhibit different frictionalproperties in their respective principal directions due to anisotropy orextrusion effects. Specimens may be tested with their long dimension ineither the machine or transverse direction of the sample, but it is morecommon practice to test the specimen as describe
46、d in 6.1 with its longdimension parallel to the machine direction.7. Preparation of Apparatus7.1 Fig. 1 shows five ways in which the apparatus may beassembled. The support bases for all apparatus assemblies shallbe level.7.2 If the apparatus of Fig. 1(a)or(b) is used, calibrate thescale of the sprin
47、g gauge as follows:7.2.1 Mount the low-friction pulley in front of the springgauge.7.2.2 Fasten one end of the nylon filament to the springgauge, bring the filament over the pulley, and suspend a knownweight on the lower end of the filament to act downward.NOTE 8The reading on the scale shall corres
48、pond to the knownweight within 65 %. The weight used for this calibration shall be between50 and 75 % of the scale range on the gauge.7.3 The drive speed for the apparatus of Fig. 1(a and b) shallbe adjusted to 150 6 30 mm/min (6.0 6 1.2 in./min). Thisspeed may be checked by marking off a 150-mm (6.
49、0 in.)section beside the plane and determining the time required forthe plane to travel 150 mm.7.4 If the apparatus of Fig. 1(c and d) employing a universaltesting machine is used, select the proper speed setting for acrosshead motion of 150 6 30 mm/min (6.0 6 1.2 in./min). Asimilar speed for the load-displacement recorder is desirable.However, the speed of the recorder can be adjusted to give thedesired accuracy in reading the pen trace.7.5 When the apparatus of Fig. 1(c) (moving sled-stationaryplane) is used, wipe the support base free of
