ASTM D1485-07(R2020) pdf free download

ASTM D1485-07(R2020) pdf free download.Standard Practice for Rubber from Natural Sources—Sampling and Sample Preparation
1. Scope
1.1 This practice, intended for referee purposes, covers a uniform procedure for sampling lots of solid natural rubber. Natural rubber generally is marketed in bales or packages of various sizes. 1.2 A procedure for determining the acceptability of lots of natural rubber is given. This procedure is based on a variable sampling plan. 1.3 The sample size is based on the assumption ofa visually homogeneous material. If obvious heterogeneity exists, the number of samples shall be increased. 1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.5 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. 1.6 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. Significance and Use
3.1 This practice outlines a procedure for sampling and sample preparation of natural rubber. A statistical method for determining a quality index and lot acceptability is given. The sampling plan is optional for quality control or production, but may be used when needed for referee purposes.
4. Sampling
4.1 Sample Size—The number of samples to be selected to represent the lot shall be determined by the size of the lot as indicated in Table 1. A sample bale is selected randomly from the lot for each sample required. N OTE 1—The sampling plan is more efficient for large lots. The risk for the producer and consumer decreases as the sample size increases. 4.2 Removal ofTest Portion: 4.2.1 From each sample bale selected, cut one 600 to 1500-g test portion of rubber, depending on the tests to be made. Each test portion is tested separately. Cut the test portion through the entire bale, normal to the bale surfaces of the largest area, without the use of lubricant. Remove outer wrapping sheets, polyethylene film, bale coating, or other extraneous surface material from the test portion. Unless the test portion is to be tested immediately, place it in an airtight container of not more than twice the volume of the test portion, or wrap it tightly in two layers of aluminum foil until tested. N OTE 2—In testing for volatile matter only, a sample weighing approximately 150 g may be taken as a continuous piece from any part of the bale.
5. Lot Acceptability
5.1 Each property of the lot is evaluated separately. The requirements of these tests are of two types: (1) those having a single limit such as a minimum or maximum and (2) those having double limits, that is, a minimum and a maximum. A quality index is calculated for each property tested, and from this index, an estimate is made of the percent of the lot that is defective. If this percentage does not exceed the allowable values shown in Table 1, the lot is considered acceptable.5.3 Acceptability: 5.3.1 For a quality characteristic having a single specifica- tion limit, a lot is acceptable if the quality index equals or exceeds the minimum quality index shown in Table 1 for the applicable lot and sample size. 5.3.2 For a quality characteristic having both an upper and lower specification limit, estimate the percentages of the lot above the upper limit and below the lower limit from Table 2 using the appropriate sample size and quality index values calculated in 5.2. A lot is acceptable if the sum of the two percentages does not exceed the maximum allowable percent defective shown in Table 1 for the lot size being evaluated.