ASTM D5179-16(R2021) pdf free download

ASTM D5179-16(R2021) pdf free download.Standard Test Method for Measuring Adhesion of Organic Coatings in the Laboratory by Direct Tensile Method
1. Scope
1.1 This test method covers the laboratory determination of organic coating adhesion to plastic substrates by mounting and removing a metal stud from the surface of the coating and measuring the force required to break the coating/substrate bond with a tensile tester. This test method may also be applied to substrates other than plastic. 1.2 This test method requires that the metal stud be adhered directly to the surface of a coated, cured panel (Fig. 1). 1.3 This test method is used to compare the adhesion of coatings to plastic or other substrates, thus allowing for a quantitative comparison of various coating/substrate combina- tions in laboratory conditions. 1.4 Other tensile test methods are Test Methods D4541, D7234, D7522, and ISO 4624 (but are not technically equiva- lent). 1.5 The values stated in SI units are to be regarded as standard. The values given in parentheses are mathematical conversions to inch-pound units that are provided for informa- tion only and are not considered standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.7 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Summary of Test Method
3.1 A metal stud is bonded directly to a coated cured panel. The adhesive is allowed to cure according to manufacturer’s recommendations. The specimen is then subjected to test on a tensile tester equipped with an upper coupling adapter (Fig. 2), and a restraining device (Fig. 3). 3.2 If a coating is to fulfill its function of protecting or decorating a substrate, it must adhere to it for the expected service life. Because the substrate and its surface preparation (or lack of it) has a drastic effect on the adhesion of coatings, a method of evaluating the adhesion of a coating to different substrates or surface treatments, or of different coatings to the same substrate and treatment, is of considerable usefulness in the industry.
4. Significance and Use
4.1 The pull-off strength (commonly referred to as adhe- sion) ofa coating is an important performance property that has been used in specifications. This test method serves as a means for uniformly preparing and testing organic coatings on plastic or other substrates. 4 Further information may be found in Appendix X1.
5. Apparatus and Materials
5.1 Tensile Tester—A properly calibrated testing machine that can be operated at constant rates of crosshead motion, and in which the error in the load measuring system shall not exceed 61 % of the maximum load expected to be measured. N OTE 1—A computer-controlled machine is preferable. 5.2 Metal Stud—The shape and dimensions of the stud are shown in Fig. 1. If aluminum studs are used, the surface for bonding may require treatment to improve adhesion. Such aluminum treatments are commercially available. 5.3 Upper Coupling Adaptor—The apparatus is shown in Fig. 2. The adaptor is 94 mm [3 3 ⁄ 4 in.] long, 31 mm [1 1 ⁄ 4 in.] in diameter at the top, and 25 mm [1 in.] in diameter at the bottom. The hole, indicated by “B,” is used to attach the adaptor to the tensile tester load cell. The hole has a 13-mm [ 1 ⁄ 2 -in.] diameter. The machined opening indicated by “A,” is to receive the head of the metal stud. 5.4 Restraining Device—The apparatus is shown in Fig. 3A and 3B. The 13-mm [ 1 ⁄ 2 -in.] diameter hole, marked “A,” in the 63.5-mm [2 1 ⁄ 2 -in.] long, 31-mm. [1 1 ⁄ 4 -in] diameter lower coupling adapter, is used to mount the device in the tensile tester. The top portion is 100 mm [4 in.] in diameter, 19 mm [ 3 ⁄ 4 in.] high, and is fitted with a hole slightly larger than 19 mm [ 3 ⁄ 4 in.] in diameter to allow stud clearance. The bottom screw portion is machined to fit with the top portion and is 13 mm [ 1 ⁄ 2 in.] thick. Fig. 3C illustrates the final appearance of the test assembly before it is tested.