GB/T 18147.4-2015Test method for hemp fiber - Part 4: Test method for fineness of hemp fiber (English PDF)

4.1 Mid-section cutter

(10±0.1) mm.

4.2 Balance

range 10 mg, division value 0.02 mg.

4.3 Electronic balance

division value 0.001 g.

4.5

Pointed stainless steel tweezers, pressure hammer, black clearer, coir scrub brush, clearer brush, glass plate, glass sheet, etc.

7.1 Conditioning

7.1.1

Laboratory samples whose moisture regain exceeds 12.0% shall be pre-baked in a 45 °C ~ 50 °C oven, so as to make the moisture regain lower than 12.0%. Carry out the moisture regain test according to GB/T 9995.

7.1.2

Put the laboratory samples under the conditions of Chapter 5 for conditioning, to reach the moisture equilibrium; the time shall not be less than 2 h.

7.2 Sample preparation

7.2.1

Take 2 test samples and 1 spare sample from the laboratory samples that have reached moisture equilibrium; arrange them by hand pulling 3 times to make the samples neat at one end.

7.2.2

Spread the samples evenly and straightly on the glass plate (bottom-lined with black clearer) along a straight line. During the arrangement process, it’s available to use the coir scrub brush to brush 2 ~ 3 times, and use tweezers to pick out the defects. The free fibers brushed off shall be re-classified into the samples after arrangement. Use tweezers to fold it into a hemp bundle with a neat end and a width of about 15 mm.

Discard short fibers below 30 mm for raw white hemp slivers, and short fibers below

15 mm for cotton type hemp fibers.

7.2.3

Again, spread the fibers evenly and straightly on the glass plate along a straight line from left to right, from long to short; divide them into 5 groups according to their lengths; use tweezers to arrange them into a hemp bundle with a neat end and a width of 10 mm ~ 15 mm, with the long fibers on the bottom and the short fibers on the top.

7.3 Testing