1、Designation: F 1536 95 (Reapproved 2005)Standard Test Method forDetermining Strength and Setting Time of Synthetic Water-Activated Polyurethane Fiberglass Orthopaedic CastingTape1This standard is issued under the fixed designation F 1536; the number immediately following the designation indicates th
2、e year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the functional diametral
3、com-pression strength of cylindrical test specimens formed fromsynthetic fiberglass polyurethane casting materials. The testspecimens employed in this test method are similar in geom-etry and construction to casts used in orthopaedic applications.This test method is not intended to determine the str
4、ength ofthe base materials used for fabrication of the test specimen.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.3 This standar
5、d 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 to use. Specific warningstatements are
6、 given in 6.7.2. Referenced Documents2.1 ASTM Standards:2E4 Practices for Force Verification of Testing MachinesE 691 Practice for Conducting an Interlaboratory Test Studyto Determine the Precision of a Test Method3. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 diametral compr
7、ession strengththe load per unitwidth in lbs/in. (Newtons/mm), calculated by dividing eitherthe peak failure load or the maximum deflection load by thenominal sample length (that is, manufacturers stated tapewidth).3.1.2 maximum deflection loadthe test cylinder is com-pressed 0.4 in. (10 mm) from th
8、e initial load position withoutnoticeable failure or a measurable decrease in load. The load at0.4 in. (10 mm) deflection shall be called the maximumdeflection load.3.1.3 peak failure loadfailure of the test cylinder with aconcomitant decrease in load prior to 0.4 in. (10 mm) diametralcompression. T
9、he highest load attained prior to the decreaseshall be called the peak failure load.4. Summary of Test Method4.1 Atest cylinder is prepared by immersing the casting tapein 75 6 2F (23.9 6 1.1C) water, squeezing per themanufacturers instructions under the surface of the water, andthen wrapping around
10、 either a 2.0 in. (50.8 mm) or 2.5 in. (63.5mm) outside diameter cylindrical mandrel. The tape is wrappedlayer upon layer producing a five layer cylinder. The testcylinder is removed from the mandrel after an initial settingperiod. After a specified time, the test specimen is positionedon its side b
11、etween two flat platens in the testing machine andcompressed to determine its strength.Ambient temperature andhumidity are specified because of their pronounced effect onmaterial properties during the curing period.5. Significance and Use5.1 Diametral compression strength is an important measureof t
12、he mechanical properties of casting materials. This testmethod simulates the loading pattern seen in lower extremitycasting applications during ambulation. This test method can-not be used to determine cast life or measure bending or othermodes of cast failure.5.2 This test method measures but does
13、not prescribe values.6. Apparatus6.1 Testing MachinesMachines used for compression test-ing shall conform to the requirements of Practices E4. Foruniversal machines with a common test space, calibration shallbe performed in compression.1This test method is under the jurisdiction of ASTM Committee F0
14、4 on Medicaland Surgical Materials and Devices and is the direct responsibility of SubcommitteeF04.15 on Material Test Methods.Current edition approved Apr. 1, 2005. Published April 2005. Originallyapproved in 1995. Last previous edition approved in 1999 as F 1536 95 (1999).2For referenced ASTM stan
15、dards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
16、PA 19428-2959, United States.6.1.1 The surfaces of the flat platens shall be perpendicularto the loading axis and parallel at all times within 0.005 in./in.(1.3 mm/mm). Platen surfaces should be clean and free ofcorrosion.6.1.2 The testing machine shall be capable of producing aconstant compression
17、rate between 1 to 10 in./min (25.4 to 254mm/min).6.1.3 The testing machine shall be capable of measuring thecompressive load within 60.5 lbs (2.2 N).6.2 Test Specimen Preparation MandrelA solid, cylindri-cal aluminum mandrel of sufficient length to accommodatethree test specimens without end contact
18、 shall be mounted in ahorizontal position (see Fig. 1). Either of two mandrel diam-eters may be used: Type I2.00 in. (50.8 mm) diameter, orType II2.50 in. (63.5 mm) diameter.6.2.1 OptionThree individual mandrels, either Type I orType II, each capable of holding one test specimen, may besubstituted f
19、or a single, solid mandrel.6.3 Constant Tension MethodEach layer of tape shall bewrapped on the mandrel at a constant tension of 0.25 lbs/in.(4.5 g/mm) width of tape. Suggested methods for accomplish-ing this include the use of a dead weight clamped to the freeend of the tape while the horizontally
20、mounted mandrel ismanually rotated (see Fig. 1), or the use of an automatedconstant torque winding mechanism (see Fig. 2).6.4 Water ContainerA container capable of holding atleast 1 gal (3.78 L) of water and of sufficient depth to allowcomplete immersion of the casting tape.6.5 Release LinerAsheet f
21、orm liner of nominal thickness,such as waxed paper, shall be used to cover the mandrel andprevent adhesion of the resin to the mandrel. This liner mustallow release of the cured specimen from the mandrel withminimal force, and must be easily removable from the speci-men inner diameter prior to compr
22、ession testing.6.6 TimerA timing device accurate to 61s.6.7 GlovesGloves capable of protecting the hands fromcontact with the resin, for example, latex surgical gloves.(WarningContact with uncured or curing resins should beavoided. These resins may adhere to the skin and be difficult toremove. In ad
23、dition, most polyurethane resins contain isocy-anate to which some individuals are or may become sensitized.Gloves should be worn at all times when handling uncured orcuring casting tape.)6.8 Thermometer A device capable of measuring tem-peratures within 61F (0.5C) in the 70 to 80F (21.1 to26.7C) ra
24、nge.7. Reagents and Materials7.1 At least three rolls of the casting tape shall be tested; oneroll for each of the three specified time periods. Three testFIG. 1 Manual Preparation MethodF 1536 95 (2005)2cylinders shall be prepared from each roll without the use ofmanual molding techniques.NOTE 1If
25、testing of cylinders with the use of manual molding isdesired, a secondary group of samples should be prepared using thedesired molding technique.7.2 Water for initiation of the curing process shall bemaintained at 75 6 2F (23.9 6 1.1C).7.2.1 The water shall be changed after three rolls have beenpre
26、pared.8. Sample Conditioning8.1 Store each package flat, with each roll on its side, at 706 5F (21.1 6 2.8C) for at least 24 h before use.8.2 Open each package immediately prior to use.9. Specimen Preparation9.1 Before opening each package, record the manufacturersname, product description, size (wi
27、dth and length), and lotnumber.9.2 Wrap the release liner around test specimen preparationmandrel and secure with tape.9.3 Open the package and loosely grasp roll with coreperpendicular to fingers in palm of hand.9.4 Start the timer, fully immerse roll in water and squeezefollowing manufacturers ins
28、tructions. Record immersion timeand number of squeezes.9.5 Remove roll from water and allow excess water to drainfor not more than five seconds. DO NOT SQUEEZE to removeexcess water.9.6 Wrap a five-ply cylinder on mandrel as rapidly aspossible using constant tension (see Fig. 1 or Fig. 2). Eachsucce
29、eding layer shall be aligned directly over the precedinglayer with complete overlap. Cut the tape at the end of the fifthply within 614 in. (6.4 mm) relative to the starting end of thefirst ply.9.7 Immediately wrap a second five-ply cylinder as rapidlyas possible by repeating 9.6.9.8 Immediately wra
30、p a third five-ply cylinder as rapidly aspossible by repeating 9.6. Cut off excess tape.9.9 MoldingPrimary test samples should be preparedwithout the use of manual molding. If testing of samples withthe use of manual molding is desired, a secondary group ofsamples should be prepared using the desire
31、d molding tech-nique. Record the molding time and degree of manipulationused.9.10 Setting TimeThis is determined by a manual inden-tation test, that is, the time elapsed from the initial immersionuntil the test cylinder cannot be indented by moderate finger-nail pressure. Begin indentation testing f
32、or material settingafter all three samples from a single roll are wrapped. Repeatthe test every 15 s until all samples are set. Record the threetimes and report the average as the setting time.9.11 After the test cylinders have set, remove them from themandrel taking care to avoid deforming them. Re
33、move therelease liner from the inside of the test cylinders.9.12 Stand test specimens on end with enough space be-tween samples to allow air to freely circulate between thecylinders.10. Procedure10.1 Testing SpeedThe recommended constant crosshead(or actuator) speed shall be between 1 to 10 in./min
34、(25.4 to254 mm/min). Report the exact speed.NOTE 2Testing speeds outside the recommended range may be usedprovided that there are no demonstrable rate dependent effects on thematerial and that complete data capture is assured at higher rates.10.2 Load Range SelectionSet the load range of thetesting
35、machine so that the maximum expected load is at least20 % of the range selected.10.3 Thirty Minute Diametral Compression StrengthThistest is performed 30 6 5 min after the time of initial immersionof the sample roll.10.3.1 Place each specimen, one at a time, between theplatens of the testing machine
36、. Center the test cylinder on thelower platen, the platen being sufficiently large to support thespecimen over its entire length. Orient the test cylinder so thatFIG. 2 Automated Constant Torque Preparation MethodF 1536 95 (2005)3the transition or overlap area, that is, where the first ply beginsand
37、 the fifth ply ends, is in contact with either the upper orlower platen.NOTE 3The presence or absence of an overlap between the first andfifth ply affects the strength of the transition area, by either increasing ordecreasing it from that of the surrounding area with a uniform number ofplies. Since
38、sample failure generally occurs in regions of high tensilestress on the free outer wall of the test cylinder, it is important that theoverlap, or transition area, not be in the high tensile stress region.10.3.2 Bring the platens together until they just touch thetest cylinder, but no load has been a
39、pplied.10.3.3 Initiate the test at the prescribed rate. Continue thetest at a uniform rate until the one of the following conditionsoccurs: either cylinder failure occurs or the maximum deflec-tion is reached.10.3.4 If the test cylinder has not set in 30 min, do not testfor the 30 min diametral comp
40、ression strength.10.3.5 Record for each cylinder the maximum reading inpounds (Newtons), that is, the peak failure load or themaximum deflection load, whichever occurs first. The 30 mindiametral compression strength is the average of the threevalues calculated from the readings.10.4 Sixty Minute Dia
41、metral Compression StrengthThistest is identical to the 30 min diametral compression test and isperformed 60 6 5 min after the time of initial immersion of thesample roll.10.5 Twenty-Four Hour Diametral Compression StrengthThis test is identical to the 30 and 60 min diametral compres-sion tests and
42、is performed 24 h 6 30 min after the time ofinitial immersion of the sample roll.10.5.1 Maintain specimens for the 24 h diametral compres-sion test at 75 6 5F (23.9 6 2.8C) and 50 6 10 % relativehumidity for the 24 h curing period.11. Report11.1 Report the following information:11.1.1 Product Identi
43、tyManufacturer, product descrip-tion, product size (width and length) and manufacturing lotcode,11.1.2 Initiation DataTotal immersion time and numberof squeezes used for initiation of polymerization,11.1.3 Set TimeAverage of the three measurements (inseconds),11.1.4 Constant Tension MethodManual or
44、automated,11.1.5 Mandrel TypeType I or Type II,11.1.6 Testing SpeedReport crosshead or (actuator) dis-placement rate as inch/min (mm/min),11.1.7 Diametral Compression StrengthsAverage of thethree (3) calculated values for each roll tested at each timeinterval. Report the load type (peak failure or m
45、aximumdeflection), and11.1.8 MoldingDegree and duration of molding used on asecondary set of samples.12. Precision and Bias12.1 Precision and bias of this test method will be deter-mined after interlaboratory tests are carried out and the resultstabulated. The interlaboratory tests will be carried o
46、ut follow-ing Practices E 691.13. Keywords13.1 orthopaedic casting tapediametral compressionstrength; orthopaedic casting tapemechanical testing; ortho-paedic casting tapesetting time; polyurethanebiomedicalapplications; polyurethane/fiberglass orthopaedic casting tapeAPPENDIX(Nonmandatory Informati
47、on)X1. RATIONALEX1.1 The primary purpose of this test method is to providea standard method for determining the strength and setting timeof synthetic water-activated polyurethane fiberglass ortho-paedic casting tape. This includes sample preparation, testingprocedure, and data reporting.X1.2 Specime
48、n preparation in this test method is notintended to duplicate all actual casting tape use. It is intendedto produce uniform samples upon which mechanical testingmay be performed with minimal variability.X1.3 Wrapping by hand may produce samples in whichthere are variations in adhesion between layers
49、, or along thesample width because of variations in wrapping tension.Sample to sample variation may also be increased when usingmanual methods. Therefore, samples should be prepared usinga method that employs constant tension during wrapping of theplies (see Fig. 1 and Fig. 2).X1.4 Manual molding of the casting tape, while an integralpart of the normal cast application process, is extremelysubjective, making standardization of this process difficult.Variations in molding pressure and molding time can greatlyinfluence test result
