GB/T 18147.3-2015 English PDF (GBT18147.3-2015)

This Part of GB/T 18147 specifies the test method for length of hemp fiber. This Part applies to raw white hemp sliver and cotton type hemp fiber.

GB/T 18147.3-2015
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 59.060.10
B 32
Replacing GB/T 18147.3-2000
Test method for hemp fiber - Part 3: Test method for length
of hemp fiber
ISSUED ON: JULY 03, 2015
IMPLEMENTED ON: OCTOBER 01, 2015
Issued by: General Administration of Quality Supervision, Inspection and Quarantine;
Standardization Administration of the People’s Republic of China.
Table of Contents
Foreword ... 3
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 5
4 Principle ... 6
5 Instruments and tools ... 6
6 Test conditions ... 6
7 Sampling ... 6
8 Conditioning ... 6
9 Test steps ... 6
10 Experimental calculation ... 8
11 Test report ... 9
Test method for hemp fiber - Part 3: Test method for length
of hemp fiber
1 Scope
This Part of GB/T 18147 specifies the test method for length of hemp fiber. This Part applies to raw white hemp sliver and cotton type hemp fiber.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies to this document. For undated references, the latest edition (including any amendment) applies to this document.
GB/T 8170, Rules of rounding off for numerical values & expression and judgment of limiting values
GB/T 9995, Determination of moisture content and moisture regain of textile - Oven- drying method
GB/T 18146.2, Hemp fiber - Part 2: Raw white hemp sliver
GB/T 18146.3, Hemp fiber - Part 3: Cotton type hemp fiber
3 Terms and definitions
The following terms and definitions are applicable to this document.
3.1
Average length
The average value obtained by weighting the mass of each group of fibers which are measured in groups by length.
3.2
Short fiber content
The percentage of the mass of short fibers shorter than a certain length limit in the hemp fiber TO the total fiber mass.
respectively, so that the fibers become relatively straight bundle which is neat at one end.
9.1.2 Lay the samples, from long to short in a straight line, evenly and straightly on the glass plate (bottom-lined with black clearer) from left to right; during the arrangement process, use a coir scrub brush to arrange for several times, and use tweezers to pick up hemp grains, hard strips, etc. The free fibers brushed off shall be re-classified into the sample after arrangement.
9.1.3 Use tweezers to arrange the fibers into a hemp bundle with a neat end and a width of 15 mm, with the long fibers on the bottom and the short fibers on the top. 9.1.4 Again, spread the fibers evenly and straightly on the glass plate along a straight line, and divide them into five groups from long to short. Use tweezers to fold each group to form a small bundle, with the long fiber on the bottom and the short fiber on the top, whose width is approximately 10 mm ~ 15 mm; use a pressure hammer or glass sheet to press it.
9.2 Testing
9.2.1 Method A - Length measurement by comb sorter (applicable to slivers) 9.2.1.1 Arrange the sorted straight fiber bundles on the top of the lower comb piece of the comb sorter group by group, with the neat end flush with the first comb piece; use a pressing fork to press the fibers straightly into the lower comb piece. 9.2.1.2 Press the upper comb piece into the lower comb piece.
9.2.1.3 Use a clip to extract the fibers from the longest end of the fibers, by as small amount as possible and as many times as possible, so as to avoid taking out short fibers. 9.2.1.4 Twist the extracted fibers into small strands by groups and place them in a metal box or a black clearer in sequence. After each extraction of a group, put down a lower comb piece, until each group of fibers is extracted.
9.2.1.5 Starting from the shortest group, weigh the mass of each group of fibers on the balance in turn, and record it.
9.2.2 Method B - Manual grouping and weighing method
9.2.2.1 Press out a straight-line trace on the black clearer; hold the neat end of the neatly arranged straight fiber bundle; fold the other end into a pen tip; use a clip to extract the fibers from long to short; arrange the fibers evenly on the black clearer along the straight line from left to right, where the fibers are required to be straight and parallel; use a measuring scale to measure the length of the fibers.
9.2.2.2 Regulations for grouping of fiber length: