ASTM F88-15 pdf free dwonload.Standard Test Method for Seal Strength of Flexible Barrier Materials.
4. Significance and Use
4.1 Seal strength is a quantitative measure for use in process validation, process control, and capability. Seal strength is not only relevant to opening force and package integrity, hut to measuring the packaging processes’ ability to produce consistent seals. Seal strength at some minimum level is a necessary package requirement, and at times it is desirable to limit the strength of the seal to facilitate opening.
4.1.1 The maximum seal force is important information, but for some applications, average force to open the seal may be useful, and in those cases also should be reported.
4.2 A portion of the force measured when testing materials may be a bending component and not seal strength alone. A number of fixtures and techniques have been devised to hold samples at various angles to the pull direction to control this bending force. Because the effect of each of these on test results is varied, consistent use of one technique (Technique A, Technique B, or Technique C) throughout a test series is reconimended. Examples of fixtures and techniques are illustrated in Fig. 1.
4.2. 1 Technique A: Unsupported—Each tail of the specimen is secured in opposing grips and the seal remains unsupported while the test is being conducted.
4.2.2 Technique B: Supported 900 (By Hand)—Each tail of the specimen is secured in opposing grips and the seal remains hand-supported at a 90° perpendicular angle to the tails while the test is being conducted.
4.2.3 Technique C: Supported 180°— The least flexible tail is supported flat against a rigid alignment plate held in one grip. The more flexible tail is folded 1 800 over the seal and is held in the opposing grip while the test is being conducted.
S. Interferences
5.1 The value obtained for seal strength can be affected by properties of the specimen other than seal strength. These interferences are discussed in the annex.
6. Apparatus
6.1 Tensile Testing Machine—A testing machine of the constant rate-of-jaw-separation type. The machine shall be equipped with a weighing system that moves a maximum distance of 2 % of the specimen extension within the range being measured. The machine shall be equipped with a device for recording the tensile load and the amount of separation of the grips; both of these measuring systems shall be accuratc to 62 O/ The rate of separation of the jaws shall be uniform and capable of adjustment from approximately 8to 12 in. [200 to 300 mml/min]. The gripping system shall be capable of minimizing specimen slippage and applying an even stress distribution to the specimen.
6. 1. 1 If calculation of average seal strength is required, the tcstir machine system shall have the capability to calculate its value over a specified range of grip travel programmable by the operor. Preferably, the machine shall have the capability also to plot the curve of force versus grip travel.ASTM F88 pdf download.