ASTM D7842-12(R2021) pdf free download

ASTM D7842-12(R2021) pdf free download.Standard Test Method for Holding Strength of Tack and Prong Fastener Attached Buttons
1. Scope
1.1 This test method covers the determination ofthe holding strength of a tack and prong fastener attached button using a tensile testing machine. 1.2 This test method is applicable to attached buttons in garments or to be attached to fabrics intended for use in apparel (see Annex A1). 1.3 Units—The values stated in either SI units or inch- pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equiva- lents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined. 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: 3.1.1 force, n—a physical influence exerted by one body on another which produces acceleration of bodies that are free to move and deformation of bodies that are not free to move. 3.1.2 holding strength, n—in buttons, the force required to separate the button from its attached mating part or separate from the fabric it is attached to, whichever shall fail first. 3.1.3 tack attached button, n—any button that is attached by a single post product (most commonly used to attach a non metal colleted button). (See Fig. 1.) 3.1.4 prong fastener attached button, n—any button that is attached by a product with 2 or more prongs (most commonly used to attach a metal colleted button). (See Fig. 2.) 3.1.5 For definitions of other textile terms used in this standard, refer to Terminology D123.
4. Summary of Test Method
4.1 A specimen, consisting of a button and tack or prong fastener attached to a fabric, is mounted in a special test fixture on a tensile testing machine. A force is applied perpendicularly until the button separates from the tack or prong fastener, or the fabric is torn. The peak force at separation is reported as the holding strength. If the fabric tears, the peak force at fabric failure is recorded and the data is reported and considered as a different category to be reported separately from the holding strength of the fasteners.
7. Sampling, Test Specimens, and Test Units
7.1 Lot Sample: 7.1.1 For acceptance testing, randomly select the number of shipping cartons or other containers of garments as directed in an applicable material specification, contract or other agree- ment between the purchaser and the supplier. Consider the cartons or containers to be the primary sampling units. 7.2 Laboratory Sample: 7.2.1 For acceptance testing, take necessary number of garments to obtain ten attachments. Button fly attachments should be tested separately from waste band attached buttons. 7.3 Test Specimens: 7.3.1 Test ten specimens from each garment. A test speci- men consists of the button, fabric, and product (tack or prong fastener) used to attach button to fabric. The locations of the specimens must allow for secure clamping in the fixtures. Extra tests may need to be performed if fabric fails before reaching either the force specification agreed upon by the purchaser and supplier or 69 N [15.5 lb]. If the fabric fails before reaching 69 N, it is recommended to try a thicker application (more layers of fabric) if possible, until ten tested specimens have no fabric failures.
8. Preparation of Apparatus
8.1 Preparation: 8.1.1 Set up and verify the tensile testing machine according to the manufacturer’s instructions and 8.1.2 – 8.1.4. 8.1.2 Attach the upper fixture to the testing machine and check the alignment. 8.1.3 Select a force range for separation to occur between 10 % and 90 % of full scale force. 8.1.4 Set the loading rate for 300 mm ⁄min 6 10 mm/min [12.0 in. ⁄min 6 0.5 in./min].