1、Designation: D 5179 02Standard Test Method forMeasuring Adhesion of Organic Coatings to PlasticSubstrates by Direct Tensile Testing1This standard is issued under the fixed designation D 5179; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, 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 laboratory determination oforganic coating adhesion to plastic subst
3、rates by mounting andremoving an aluminum stud from the surface of the coating andmeasuring the force required to break the coating/substratebond with a tensile tester.1.2 This test method requires that the aluminum stud beadhered directly to the surface of a coated, cured panel (Fig. 1).1.3 This te
4、st method is used to compare the adhesion ofcoatings to various plastic substrates, thus allowing for aquantitative comparison of various coating/substrate combina-tions.1.4 Other tensile test methods are Test Method D 4541 andISO 4624 (but are not technically equivalent).1.5 The values stated in in
5、ch-pound units are to be regardedas the standard. The values given in parentheses are forinformation only.1.6 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 an
6、d health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:D 4541 Test Method for Pull-Off Strength of CoatingsUsing Portable Adhesion Testers22.2 Other Standard:ISO 4624 Paints and VarnishesPull-off test for adhesion33. Summa
7、ry of Test Method3.1 An aluminum stud is bonded directly to a coated curedpanel. The adhesive is allowed to cure for2hatroomtemperature. The specimen is then subjected to test on a tensiletester equipped with an upper coupling adapter (Fig. 2), and arestraining device (Fig. 3).3.2 If a coating is to
8、 fulfill its function of protecting ordecorating a substrate, it must adhere to it for the expectedservice life. Because the substrate and its surface preparation(or lack of it) has a drastic effect on the adhesion of coatings,a method of evaluation adhesion of a coating to differentsubstrates or su
9、rface treatments, or of different coating to thesame substrate and treatment, is of considerable usefulness inthe industry.4. Significance and Use4.1 The pull-off strength (commonly referred to as adhe-sion) of a coating is an important performance property that hasbeen used in specifications. This
10、test method serves as a meansfor uniformly preparing and testing organic coatings on plasticsubstrates.4Further information may be found inAppendix X1.5. Apparatus and Materials5.1 Tensile Tester, commercially available.51This test method is under the jurisdiction of ASTM Committee D01 on Paintand R
11、elated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved Dec. 10, 2002. Published February 2003. Originallyapproved in 1991. Last previous edition approved in 1998 as D 5179 98.2Annual B
12、ook of ASTM Standards, Vol 06.02.3Available from American National Standards Institute (ANSI), 25 W. 43rd St.,4th Floor, New York, NY 10036.4Gray, K. N., Buckley, S. E., and Nelson, G. L., “Accessing MeasurementStandards for Coating Adhesion to Plastics,” Modern Paint and Coatings Journal,Vol 75, No
13、. 10, October 1985, p. 160.5The sole source of supply of the wooden puritan applicators, in sizes 6 in. (150mm) in length and 0.007 in. (2 mm) in diameter, known to the committee at this timeis Hardwood Products Co., Guilford, ME 04443. If you are aware of alternativesuppliers, please provide this i
14、nformation to ASTM International. Your commentswill receive careful consideration at a meeting of the responsible technicalcommittee,1which you may attend.FIG. 1 Direct Tensile Model1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.2
15、 Aluminum StudThe shape and dimensions of the studare shown in Fig. 1.5.3 Upper Coupling AdaptorThe apparatus is shown inFig. 2. The adaptor is 334 in. (94 mm) long, 114 in. (31 mm)in diameter at the top, and 1 in. (25 mm) in diameter at thebottom. The hole, indicated by “B,” is used to attach thead
16、aptor to the tensile tester load cell. The hole has a12-in.(13-mm) diameter. The machined opening indicated by “A,” isto receive the head of the aluminum stud.5.4 Restraining DeviceThe apparatus is shown in Fig. 3Aand 3B. The12-in. (13-mm) diameter hole, marked “A,” in the212-in. (63.5-mm) long, 114
17、-in. (31-mm) diameter lowercoupling adapter, is used to mount the device in the tensiletester. The top portion is 4 in. (100 mm) in diameter,34 in. (19mm) high, and is fitted with a hole slightly larger than34 in. (19mm) in diameter to allow stud clearance. The bottom screwportion is machined to fit
18、 with the top portion and is12 in. (13mm) thick. Fig. 3C illustrates the final appearance of the testassembly before it is tested.5.5 Wooden Applicators,5used to clean the adhesive fromaround the aluminum stud.5.6 Adhesive, cyanoacrylate adhesive6. Since cyanoacrylateadhesives lose adhesive bond str
19、ength with time, do not usepreviously opened containers or lots of adhesive known to beold.5.7 Two-Kilogram Weight, approximately 2 in. (50 mm) indiameter and 5 in. (130 mm) in height.6. Preparation and Conditioning of Specimen6.1 Sanding ProcedureSand the large face of stud with80-grit sandpaper, m
20、aking certain that the surface is uniformlyroughened. When sanding studs, sand straight up and down;rotate stud one quarter of a turn and continue sanding. Makecertain the surface of the stud is flat but rough. While sanding,keep the stud face parallel to the sandpaper. Nonplanar surfacescannot be u
21、sed in testing because they lead to nonuniformbonding of the stud to the coated surface. Only flat (planar)studs should be used in testing. Planarity may be assessed byplacing a stud on a flat surface and checking to see if the studwobbles. Careful preparation of studs is essential for goodadhesive
22、adhesion.6.2 Cleaning ProcedurePlace sanded studs in a largebeaker. Pour technical grade acetone over the studs and swirlthe beaker to completely wash the studs. Pour out acetone andrepeat the cleaning procedure. Soak the stud for at least 15 min,pour out the acetone, and allow the studs to dry.6.3
23、Place washed and dried studs and beaker in an oven at120C and allow to heat for 1 h. Remove the beaker and studsfrom the oven and allow to cool. DO NOT TOUCH FACE OFSTUDS.6.4 Spread four drops of cyanoacrylate adhesive on thelarge face of an aluminum stud. Next, quickly press the studonto the coated
24、 test substrate. Place a 2-kg weight on the studto ensure good contact between the stud, adhesive, and surfaceof the coating. Clean the excess adhesive from the edge of thestud with a wooden applicator. Carefully remove the weightafter 2 min.NOTE 1Substrate panels may be cut to any size that fits th
25、e restrainingdevice.NOTE 2When the stud is pressed, excess adhesive should escape fromunder the stud. Excess adhesive buildup at the edge of the stud is a majorsource of error if allowed to dry. This excess must be removed fromaround the stud. The adhesive may be removed using a wooden applicatorand
26、 an absorbent, creped, low-lint material. Some workers have foundcotton swabs also work well when removing the excessive adhesive.6.5 Allow the sample to cure for2hatroom temperature(see Note 3).NOTE 3The time specified led to the results reported in the Precisionand Bias Section. If other than the
27、recommended adhesive is used, the usershould be guided by the cure time recommended by the adhesivemanufacturer. A series of preliminary tests at several cure times may benecessary in the selection of a time that ensures cure of the adhesive used.NOTE 4When reusing aluminum studs, the studs must be
28、soaked inacetone to remove the coating and resanded. It has been found thatsoaking the studs in two separate acetone baths thoroughly removes theadhesive and coating. The first acetone bath is used to dissolve thecyanoacrylate adhesive, and the second is used to further clean anddissolve any coating
29、 or adhesive left on the stud. Before the studs are used,they should be resanded and cleaned with acetone as specified in 6.2, 6.3,and 6.4.6.6 ConditioningCondition the coated substrates for atleast 24 h at 23 6 2C (73.5 6 3.5F) and 50 6 5 % relativehumidity, and test in the same environment or imme
30、diately onremoval therefrom, unless otherwise specified by the purchaserand the seller.7. Procedure7.1 Install the restraining device and upper adaptor in thetensile tester.7.2 Calibrate the tensile tester. Make sure that the chartspeed is set at 8 to 20 in./min (20 to 50 cm/min). Make sure that6Elm
31、ersy Wonder Bond Plusy Super Glue, a cyanoacrylate adhesive sold byElmers Products, Inc., 180 E. Broad St., Columbus, OH 43215, was foundacceptable in the round-robin study upon which this test method is based. Otheradhesives may be used if they provide adequate adhesion between the aluminumstud and
32、 the coating being tested; the results reported in the Precision and BiasSection, however, may not apply. From other work it is noted that somecyanoacrylate adhesives may penetrate certain coatings and soften the coating or theplastic substrate. The same is true for other adhesives. Care in observat
33、ion ofunusual results is necessary to ensure against the possibility of error. This latter isto be suspected if an adhesive gives an unexpectedly low result.Adhesives that yielda brittle adhesive layer should not be used.FIG. 2 Upper Coupling AdaptorD5179022the crosshead speed is set at 2 in./min (5
34、 cm/min). Make surethat the chart full scale is set at 100 kg.7.3 Place the specimen to be tested in the restraining device(Fig. 3A and 3B). Pre-position the crosshead and then slowlylower it so the upper coupling adaptor can be attached to thetest specimen. Take care to prevent the crosshead fromim
35、pacting into the top of the specimen. Carefully attach theupper coupling adaptor to the stud (Fig. 3C).NOTE 5When testing thin substrates, a piece of plastic may be placedin the restraining device behind the test specimen to prevent the substratefrom flexing when the stud is pulled from it.7.4 Turn
36、on the chart recorder and pen. Start the tensile test.Stop the test when the stress returns to zero on the chart.7.5 Examine the test area on each specimen to determine thetype of coating failure, rating it according to the following:7.5.1 Adhesive failure of the coating at the substrate, A,7.5.2 Co
37、hesive failure in the coating, C,7.5.3 Combination of adhesive failure at the coating/substrate interface and cohesive failure in the coating, AC,7.5.4 Adhesive failure at the stud, S, and7.5.5 Combination of adhesive failure at the stud andcohesive failure in the coating, CS.7.6 For multilayer coat
38、ings, note if the failure is between thelayers. If so, label as CM.7.7 Number and retain all test specimens for adhesionfailure calculations. Test five specimens of each coated sub-strate one day and five on a second day. If one specimen differssignificantly from the other four at the same time, fai
39、ls becauseof an uneven (nonplanar) stud, or for any other reason performsunlike the other four, test a replacement specimen.NOTE 6Examine the stud and specimen carefully. Adhesive shouldhave been applied uniformly to the entire stud surface. Coating shouldhave pulled off uniformly over the entire st
40、ud surface either with adhesivefailure from the substrate (A) or cohesive failure in the coating (C). Iffailure is less than 90 % A or C or (or CM), if the adhesive has failed atthe stud, retest exercising particular care in the specimen and studpreparation.NOTE 7The percentage of adhesive failure a
41、t the coating/substrateinterface is determined by inspecting the tested area on the substrate. Thismay be assessed by overlaying a transparent sheet grid marked in 0.10-in.(2.54-mm) squares and estimating the percentage of adhesive failure ineach square that lies over the tested area. These percenta
42、ges may then beaveraged to obtain failure for each specimen.NOTE 8Sample conditioning, if any, and humidity and temperature oftest room may affect results. Notation of these conditions should be madeon the test report.8. Report8.1 Report the number of tests, the maximum stress ob-tained in each test
43、, and the type of failure. Test data sheet isshown in Fig. 4. Fill in data sheet with results obtained fromeach test. Attach tensile test traces to the data sheets. Calculateand report mean and standard deviation for tensile strength foreach coating/substrate combination tested.9. Precision and Bias
44、79.1 The precision and bias are primarily dependent upon theaccuracy of the force measurements, the alignment of thedevice, the care exercised in stud and specimen preparation,and the care in testing.9.2 A round robin involving five different types of coatingsand seven different plastic substrates,
45、and ten different labora-tories yielded interlaboratory reproducibility data as shown inTable 1. Within laboratory repeatability data is shown in Table2 and Table 3.9.3 BiasNo information can be provided on the bias ofthis test method for measuring adhesion because no materialhaving an accepted refe
46、rence value is available.10. Keywords10.1 adhesion; bond strength; cyanoacrylate adhesive; plas-tic substrate; pull-off strength; pull testing; tensile tester7A complete report with additional data is available. See Nelson, G. L., “Testingof EMI/RFI Coating Adhesion to Plastics by a Tensile Test Met
47、hod,” Final Reportfor Computer and Business Manufacturers Association and Society of the PlasticsIndustry, University of Southern Mississippi, June, 1989.FIG. 3 Direct Tensile Restraining DeviceD5179023FIG. 4 Coating Adhesion Testing by Direct Tensile MethodsTABLE 1 Overall Test ReproducibilityNOTE
48、1This data was generated with lesser cautionary language thanfound in Note 2 and includes laboratories who had not removed excessadhesive. With experienced operators, reproducibility data can be antici-pated to be better than shown in Table 1.Ten LaboratoriesSample Kilogram Force Standard Deviation1
49、 34.6 6.72 36.2 9.33 19.8 4.54 26.7 8.75 31.7 9.96 26.0 7.27 41.6 9.28 16.6 6.59 60.5 20.510 28.3 9.8D5179024APPENDIX(Nonmandatory Information)X1. COMMENTARYX1.1 IntroductionX1.1.1 Given the complexities of the adhesion process, canadhesion be measured? As Mittal (1-5)8has pointed out, theanswer is both yes and no. It is reasonable to state that at thepresent time no test exits that can precisely assess the actualphysical strength of an adhesive bond. But it can also be saidthat it is possible to obtain an indication of relative adhesionperformance.X1.1.
