ASTM D925-14(R2019) pdf free download
ASTM D925-14(R2019) pdf free download.Standard Test Methods for Rubber Property—Staining of Surfaces (Contact, Migration, and Diffusion)
1. Scope
1.1 These test methods cover techniques to evaluate three types of staining that rubber may cause when in contact with, or in proximity to, another surface that may be light colored. 1.2 The test methods also describe how to qualitatively evaluate the degree of staining produced under the conditions of exposure to heat alone or heat and light. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. 1.4 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. 1.5 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. Terminology
3.1 Definitions ofTerms Specific to This Standard: 3.1.1 stain, contact—discoloration of a product by another material or product in the area of direct contact. 3.1.1.1 Discussion—A test for direct surface discoloration of rubber is covered by Test Method D1148. 3.1.2 stain, diffusion—discoloration of a light colored ve- neer or coating, caused by the diffusion of staining materials from the rubber through the veneer or coating. 3.1.2.1 Discussion—The veneer or coating is in direct inti- mate contact with the underlying rubber. 3.1.3 stain, migration—discoloration, caused by constitu- ents of a rubber, that occurs on any portion of the surface of any object in the proximity of or adjacent to but not in direct contact with the rubber causing the stain.
4. Summary of Test Methods
4.1 The test methods are as follows: 4.1.1 Method A—Contact Stain. 4.1.2 Method B—Migration Stain. 4.1.3 Method C—Diffusion Stain. 4.2 Method A—Specimens to be tested for contact staining are sandwiched between two metal panels. The metal panels are furnished with a desired light colored organic finish, which is in contact with the rubber. The assembly is exposed to elevated temperatures for a specified length of time and the specimens are then removed from the metal. The degree of staining of the surface that was in contact with the rubber is rated against a reference standard and a control panel (a metal plate without rubber) which are simultaneously tested with the specimen.4.3 Method B—Specimens to be tested for migration stain- ing are placed on a metal plate with a desired light colored organic finish, and exposed to either fluorescent UVA-340 lamps or filtered xenon arc radiation for a specified period of time. The degree ofstaining beyond the area that was in contact with the specimens is then rated against a reference standard and a control panel (a metal plate without rubber) which are simultaneously tested with the specimen. 4.4 Method C—Diffusion staining is tested on specimens provided with a light colored rubber veneer or organic coating, deposited from organic solvent or water base. The specimens are exposed to either fluorescent UVA-340 lamps or filtered xenon arc radiation, with their veneer or coated side up, for a specified period of time. Any staining of the light colored veneer or organic coating is considered diffusion staining and rated against a reference standard and a control sample of the veneer or organic coating without the staining rubber. 4.5 Specimens used in all three staining tests shall include one or more reference samples of known staining characteris- tics. In addition, the contact and migration staining tests shall include a metal panel, without rubber samples, to establish the effect of the test conditions on the finished metal surface. The diffusion staining test shall include, as controls, a vulcanized sample ofthe rubber veneer by itselfor a sample ofthe coating applied to aluminum foil.
