ASTM D646-96(R01) 纸张及纸板的基本重量的试验方法(单位面积的重量)【英文版】

ASTM D646-96(R01)  纸张及纸板的基本重量的试验方法(单位面积的重量)【英文版】.pdf
Designation: D 646 – 96 (Reapproved 2001) An American National Standard
Technical Association of Pulp
and Paper Industry
Test Method T 410 om-88.
Standard Test Method for
Grammage of Paper and Paperboard (Mass Per Unit Area)1
This standard is issued under the fixed designation D 646; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
This standard has been approved for use by agencies of the Department of Defense.
1. Scope
1.1 This test method covers the determination of the grammage
of paper and paperboard (mass per unit area). In
English-speaking countries the customary or commercial practice
of expressing the “weight” per unit area (more properly
“mass per unit area”) of paper has been “basis weight,” “ream
weight,” or “substance,” defined as the mass in pounds of a
ream of a given sheet size and number of sheets (usually 500
sheets, occasionally 480 sheets). In most other countries and
increasingly in English-speaking countries, the mass per unit
area is expressed in grams per square metre. The French term
for mass per unit area,“ grammage,” is recommended by ISO
Committee TC 6 on Paper for use in English as well as in
French because of its convenience and clear relationship to
grams per square metre.
1.2 The mass per unit area of paperboard has been expressed
in the customary system as the mass in pounds per
thousand square feet, and in the metric system as grams per
square metre.
1.3 The SI metric units, in which grammage (mass per unit
area) is expressed in grams per square metre (g/m2), are the
preferred units for ASTM test methods for paper and paperboard.
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 appropriate
safety and health practices and determine the applicability
of regulatory limitations prior to use.
2. Referenced Documents
2.1 ASTM Standards:
D 585 Practice for Sampling and Accepting a Single Lot of
Paper, Paperboard, Fiberboard, and Related Product2
D 685 Practice for Conditioning Paper and Paper Products
for Testing2
3. Summary of Test Method
3.1 The area of several sheets of the paper or paperboard is
determined from linear measurements and the mass (commonly
called “weight”) is determined by weighing. The
grammage is calculated from the ratio of the mass to the area
after conversion to metric units when necessary.
4. Significance and Use
4.1 Most paper is bought and sold in accordance with its
mass per unit area, and therefore the grammage has great
significance both to the consumer and the producer in defining
price. Also the values of many physical properties such as
bursting strength, thickness, and bulk are interpreted and
specified with regard to the particular grammage involved.
5. Apparatus
5.1 Weighing Device, readable and accurate to within
0.25 % of the applied load. When in use, the weighing device
shall be shielded from air currents.
5.1.1 Special sheet-weighing devices designed to weigh test
specimens of a given size may be used, provided that the above
conditions are fulfilled and that the total area of each test
specimen (see 6.3) in a single weighing is not less than 500
cm2(80 in.2).
5.1.2 For a test specimen of smaller total area, an analytical
balance is essential to obtain the required accuracy.
5.2 Cutting Device, such as a “four square” cutter, or other
device for ensuring parallelism of the opposite edges, normally
capable of repeatedly cutting out test specimens whose area, in
at least 95 instances out of 100, falls within 60.5 % of a known
area, as determined by the method specified in 7.2.
5.2.1 When a template is used for preparing test specimens,
the paper should be cut to exact size with a sharp knife on a
hard surface, such as a hardwood board.
1 This test method is under the jurisdiction of ASTM Committee D06 on Paper
and Paper Products and is the direct responsibility of Subcommittee D06.92 on Test
Methods.
Current edition approved Jan. 10, 1996. Published March 1996. Originally
published as D 646 – 41 T. Discontinued 1981 and reinstated 1986. Last previous
edition D 646 – 92 (1995)e1.
This test method is related to TAPPI T 410 om-83, which is technically identical,
and is similar to International Standard ISO 536, Paper and Board—Determination
of Grammage. 2 Annual Book of ASTM Standards, Vol 15.09.
1
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
5.3 Scale, such as a finely graduated steel rule reading in 0.5
mm (1⁄50 or 1⁄64 in.), capable of measuring the dimensions of the
test specimen to an accuracy of 0.2 %.
6. Sampling
6.1 Obtain the sample of the paper or paperboard to be
tested in accordance with Method D 585.
6.2 From each test unit of the sample, cut a sufficient
number of representative sheets for a total area per test unit of
at least 5000 cm2(800 in.2). The dimensions and hence the area
of each sheet will depend on the sheet cutting device available.
If a template is used, a minimum dimension of 20.0 by 25.0 cm
(8 by 10 in.) is recommended.
6.3 Select the number of sheets composing a test specimen
(total area of each test specimen at least 500 cm2) to give the
required weighing accuracy.
NOTE 1—As a consequence of the above rules, which allow for
flexibility in the selection of sheet weighing and cutting devices, the
number of test specimens representing a test unit and the number of sheets
per test specimen will depend on the choice of weighing and cutting
devices, as illustrated by the following examples:
(a) If for a particular sample of paper, the sheet weighing device requires
the weighing together of two sheets at least 20.0 by 25.0 cm to obtain the
requisite weighing accuracy, then each test specimen will consist of two
sheets at least 20.0 by 25.0 cm, and five such test specimens (each a pair
of sheets) will be needed to obtain the required total area of 5000 cm2.
(b) If the available precise cutting device gives a sheet size of 4.00 by 4.00
in. (approximately 10 by 10 cm), then for the same paper and sheet
weighing device used above, each of the needed five test specimens would
require ten sheets.
NOTE 2—For some uses, the variation across the web or roll may be of
interest; for example, the original wide role (or web) may be slit into
narrow rolls, each 7.5 to 10 cm (3 to 4 in.) wide for medical packaging.
A “tailing-off” of the grammage near the edge of the web could be
unacceptable. In such cases, test units using narrow sheets should be taken
from selected positions across the web and the grammage reported
separately for each position.
7. Calibration
7.1 Checking of Weighing Device:
7.1.1 Check the accuracy of the weighing device frequently
(7.3) by applying accurately measured masses with both
increasing and decreasing loads. When using a sheet-weighing
device, be sure that the device has been properly calibrated to
the required accuracy (5.1).
7.1.2 Before each use, see that frictional effects are sufficiently
minimal and that the zero reading is sufficiently correct
as to assure the required weighing accuracy.
7.2 Checking of Cutting Device—Frequently (7.3) check the
area cut by using the scale (5.3) to measure 20 test specimens.
The cutting accuracy specified in 5.2 is attained when the
standard deviation of the individual areas is less than 0.25 % of
the mean area, in which case this mean area may be used for
calculating grammage in subsequent tests.
7.3 Frequency of Checking—The frequency of checking in
7.1 and 7.2 should be based on experience. A new device
should be checked several times before being put into use.
Then, if in continuous use, it should be checked twice daily
until stability is established, then weekly, monthly, or less
frequently as indicated by its stability, unless moved or unduly
disturbed. Because of wear, the cutting device may require
more frequent checking than the weighing device.
8. Conditioning
8.1 Condition and test the test specimens in an atmosphere
in accordance with Practice D 685, unless grammage“ as
received” is required.
8.2 The precision of this work is such that hysteresis has
important effects; therefore, precondition the test specimens so
that the equilibrium moisture content is approached from the
drier state.
9. Procedure
9.1 If the cutting accuracy specified in 5.2 is attained (see
7.2), use the mean area obtained in 7.2; otherwise, determine
the area of each test specimen to within 0.3 %, that is, measure
the dimensions of each sheet to within 0.2 %.
9.2 If the special sheet-weighing device is used, be sure that
the dimensions of the sheets are within 0.2 % of the required
size; otherwise, make a correction in accordance with the
following equation:
G 5 G8 3 ~A8/A! (1)
where:
G = corrected indicated mass per unit area,
G8 = indicated mass per unit area of the test specimen,
A8 = area of the test specimen for which the device is
calibrated, and
A = area of the weighed test specimen.
9.3 Weigh each test specimen to within 0.25 %.
10. Calculation
10.1 From the measurements, calculate the mass per unit
area of each test specimen. If M is the mass and A is the area
of the test specimen in the units of measurements, then the
grammage in grams per square metre may be calculated by the
equation:
G 5 K 3 ~M/A! (2)
where K is the conversion factor given in Table 1.
10.1.1 If the ream weight in pounds (BW) has been determined
for a customary trade size of 500 sheets, the grammage
in g/m2 may be calculated as follows:
G 5 P 3 BW (3)
where P is the conversion factor given in Table 2.
10.2 Calculate the mean of the results for each test unit, and
express in grams per square metre to three significant figures.
TABLE 1 Conversion Factors
Units of Measurement Conversion
Factors
Mass (M) K
Area
(A)
Gram cm2 10 000
Gram in.2 1 550
Indicated weight for 500-sheet ream, lb cm2 9 070
Indicated weight for 500-sheet ream, lb in.2 1 406
D 646
2
10.3 To convert grammage (G) to mass in pounds (BW) of
custom trade sizes for 500-sheet reams or, for paperboard,
1000 ft2, the following equation may be used:
BW 5 Q 3 G (4)
where Q is the conversion factor given in Table 2. Express
the results in pounds to three significant figures.
11. Report
11.1 Report the grammage in grams per square metre to
three significant figures for each test unit and, if required, for
the average of the test units drawn from the lot.
11.2 If the test units have been taken from more than one
position across a roll or sheet and information on grammage
variation is required (for example, Note 2), report the average
for each position separately.
11.3 If desired, the results may also be reported in pounds
for customary trade sizes.
11.4 If the total area of a test unit is less than that specified,
state the actual total area tested.
12. Precision and Bias
12.1 Precision
12.1.1 Repeatability of test results within a laboratory
= 0.94 %.
12.1.2 Reproducibility of test results between laboratories
= 2.84 %.
12.1.3 The above values of precision are averages calculated
from 18 reports of the TAPPI Collaborative Reference
Program for Paper. Each test result is an average for approximately
5000 cm2 of paper and paperboard.
12.1.4 The user of this precision data is advised that it is
based on actual mill testing, laboratory testing, or both. There
is no knowledge of the exact degree to which personnel skills
or equipment were optimized during its generation. The
precision quoted provides an estimate of typical variation in
test results which may be encountered when this standard
method is routinely used by two or more parties.
12.2 Bias—The procedure in this test method has no bias
because the value of grammage is defined only in terms of the
conditions stated in the test method.
13. Keywords
13.1 basis weight; grammage; mass per unit area;
paperboard
ANNEX
(Mandatory Information)
A1. REAM WEIGHT CONVERSION FACTORS
A1.1 Table 2 is for 500-sheet reams except as noted. If the
trade size uses 480-sheet reams, then the factor P is multiplied
by 50/48 or 1.042 for conversion and factor Q is multiplied by
48/50 or 0.960.
A1.2 The U.S. Government Printing Office has discontinued
using twice the trade size and is now following tradepractice.
A1.3 To within 0.5 %, mass per unit area in g/m2 is
numerically equal to basis weight in pounds (35 by 40 - 500),
so that by adjusting the size of the template most ream weight
scales may be used to read directly in g/m2.
TABLE 2 Ream Weight Conversion Factors
Kind of Paper
Trade or
Basic Size
Trade Size
Area, ft2
P
(BW to G)
Q
(G to BW)
Paperboard 1000 ft2 1000.0 4.882 0.205
Writing and printing 17 3 22 − 500 1298.6 3.760 0.266
Blotting 19 3 24 − 500 1583.3 3.084 0.324
Cover 20 3 26 − 500 1805.6 2.704 0.370
Carbon paper 20 3 30 − 500 2083.3 2.344 0.427
Cardboard 22 3 28 − 500 2138.9 2.283 0.438
Bristol and tag 221⁄2 3 281⁄2 − 500 2226.6 2.193 0.456
Binder’s board 251⁄4 3 301⁄4 − 500 2652.1 1.841 0.543
Index 251⁄2 3 301⁄2 − 500 2700.5 1.808 0.553
News, wrapping, tissue, carton board 24 3 36 − 500 3000.0 1.627 0.614
Tissue 24 3 36 − 480 2880.0 1.695 0.590
Book and offset 25 3 38 − 500 3298.6 1.480 0.676
Newsboard 26 3 38 − 500 3430.6 1.423 0.703
Former TAPPI standard size 25 3 40 − 500 3472.2 1.406 0.711
D 646
3
APPENDIX
(Nonmandatory Information)
X1. PREFERRED GRAMMAGES
X1.1 A list of preferred grammages and their trade size
equivalents is given in Table X1.1. This list is not intended to
require changes in the grammages of currently manufac-tured
products, but is recommended for consideration when product
changes are made.
TABLE X1.1 Conversion of Grammage to Pounds per Ream (500 Sheets)
Grammage 1000 ft2
0.205
17 by
22
0.266
19 by
24
0.324
20 by
26
0.370
20 by
30
0.427
22 by
28
0.438
221⁄2 by
281⁄2
0.456
251⁄2 by
301⁄2
0.553
24 by
36
0.614
25 by
38
0.676 A B
10 2.0 2.7 3.2 3.7 4.3 4.4 4.6 5.5 6.1 6.8
10.5 2.2 2.8 3.4 3.9 4.5 4.6 4.8 5.8 6.5 7.1
11 2.3 2.9 3.6 4.1 4.7 4.8 5.0 6.1 6.8 7.4
12 2.5 3.2 3.9 4.4 5.1 5.3 5.5 6.6 7.4 8.1
12.5 2.6 3.3 4.1 4.6 5.3 5.5 5.7 6.9 7.7 8.4
13 2.7 3.5 4.2 4.8 5.5 5.7 5.9 7.2 8.0 8.8
14 2.9 3.7 4.5 5.2 6.0 6.1 6.4 7.7 8.6 9.5
15 3.1 4.0 4.9 5.5 6.4 6.6 6.8 8.3 9.2 10.1
16 3.3 4.3 5.2 5.9 6.8 7.0 7.3 8.8 9.8 10.8
17 3.5 4.5 5.5 6.3 7.3 7.4 7.8 9.4 10.4 11.5
18 3.7 4.8 5.8 6.7 7.7 7.9 8.2 10.0 11.1 12.2
19 3.9 5.1 6.2 7.0 8.1 8.3 8.7 10.5 11.7 12.8
20 4.1 5.3 6.5 7.4 8.5 8.8 9.1 11.1 12.3 13.5
21 4.3 5.6 6.8 7.8 9.0 9.2 9.6 11.6 12.9 14.2
22 4.5 5.9 7.1 8.1 9.4 9.6 10.0 12.2 13.5 14.9
24 4.9 6.4 7.8 8.9 10.2 10.5 10.9 13.3 14.7 16.2
25 5.1 6.6 8.1 9.2 10.7 11.0 11.4 13.8 15.4 16.9
26 5.3 6.9 8.4 9.6 11.1 11.4 11.9 14.4 16.0 17.6
28 5.7 7.4 9.1 10.4 11.9 12.3 12.8 15.5 17.2 18.9
30 6.1 8.0 9.7 11.1 12.8 13.1 13.7 16.6 18.4 20.3
32 6.6 8.5 10.4 11.8 13.7 14.0 14.6 17.7 19.7 21.6
34 7.0 9.0 11.0 12.6 14.5 14.9 15.5 18.8 20.9 23.0
36 7.4 9.6 11.7 13.3 15.4 15.8 16.4 19.9 22.1 24.3
38 7.8 10.1 12.3 14.1 16.2 16.6 17.3 21.0 23.3 25.7
40 8.2 10.6 13.0 14.8 17.1 17.5 18.2 22.1 24.6 27.0
42 8.6 11.2 13.6 15.5 17.9 18.4 19.2 23.2 25.8 28.4
45 9.2 12.0 14.6 16.6 19.2 19.7 20.5 24.9 27.7 30.4
48 9.8 12.8 15.6 17.8 20.5 21.0 21.9 26.5 29.5 32.4
50 10.2 13.3 16.2 18.5 21.3 21.9 22.8 27.7 30.7 33.8
53 10.9 14.1 17.2 19.6 22.6 23.2 24.2 29.3 32.6 35.8
56 11.5 14.9 18.2 20.7 23.9 24.5 25.5 31.0 34.4 37.8
60 12.3 16.0 19.5 22.2 25.6 26.3 27.4 33.2 36.9 40.5
63 12.9 16.8 20.4 23.3 26.9 27.6 28.7 34.8 38.7 42.6
67 13.7 17.8 21.7 24.8 28.6 29.4 30.6 37.1 41.2 45.3
71 14.5 18.9 23.0 26.3 30.3 31.1 32.4 39.3 43.6 48.0
75 15.4 19.9 24.3 27.7 32.0 32.9 34.2 41.5 46.1 50.7
80 16.4 21.3 25.9 29.6 34.1 35.0 36.5 44.2 49.2 54.0
85 17.4 22.6 27.6 31.4 36.3 37.2 38.8 47.0 52.2 57.4
90 18.4 23.9 29.2 33.3 38.4 39.4 41.0 49.8 55.3 60.8
95 19.5 25.3 30.8 35.1 40.5 41.6 43.3 52.5 58.4 64.2
100 20.5 26.6 32.4 37.0 42.7 43.8 45.6 55.3 61.4 67.6
105 21.5 27.9 34.1 38.8 44.8 46.0 47.9 58.1 64.5 70.9
110 22.5 29.3 35.7 40.7 46.9 48.2 50.2 60.8 67.6 74.3
120 24.6 31.9 38.9 44.4 51.2 52.6 54.7 66.4 73.7 81.1
125 25.6 33.2 40.5 46.2 53.3 54.8 57.0 69.1 76.8 84.5
130 26.6 34.6 42.2 48.1 55.5 57.0 59.3 71.9 79.9 87.8
140 28.7 37.2 45.4 51.8 59.7 61.3 63.8 77.4 86.0 94.6
150 30.7 39.9 48.6 55.5 64.0 65.7 68.4 83.0 92.2 101.3
160 32.8 42.6 51.9 59.2 68.3 70.1 73.0 88.5 98.3 108.1
170 34.8 45.2 55.1 62.9 72.5 74.5 77.5 94.0 104.5 114.9
180 36.9 47.9 58.4 66.6 76.8 78.9 82.1 99.6 110.6 121.6
190 38.9 50.5 61.6 70.3 81.1 83.2 86.6 105.1 116.7 128.4
200 41.0 53.2 64.9 74.0 85.3 87.6 91.2 110.6 122.9 135.1
210 43.0 55.9 68.1 77.7 89.6 92.0 95.8 116.2 129.0 141.9
220 45.1 58.5 71.3 81.4 93.9 96.4 100.3 121.7 135.2 148.6
240 49.2 63.8 77.8 88.8 102.4 105.1 109.4 132.7 147.5 162.1
250 51.2 66.5 81.1 92.5 106.7 109.5 114.0 138.3 153.6 168.9
D 646
4
TABLE X1.1 Continued
Grammage 1000 ft2
0.205
17 by
22
0.266
19 by
24
0.324
20 by
26
0.370
20 by
30
0.427
22 by
28
0.438
221⁄2 by
281⁄2
0.456
251⁄2 by
301⁄2
0.553
24 by
36
0.614
25 by
38
0.676 A B
260 53.3 69.2 84.3 96.2 110.9 113.9 118.6 143.8 159.8 175.7
280 57.3 74.5 90.8 103.5 119.5 122.7 127.7 154.9 172.0 189.2
300 61.4 79.8 97.3 110.9 128.0 131.4 136.8 165.9 184.3 202.7
320 65.5 85.1 103.8 118.3 136.5 140.2 145.9 177.0 196.6 216.2
340 69.6 90.4 110.3 125.7 145.1 148.9 155.1 188.1 208.9 229.7
360 73.7 95.8 116.7 133.1 153.6 157.7 164.2 199.1 221.2 243.2
380 77.8 101.1 123.2 140.5 162.1 166.5 173.3 210.2 233.5 256.7
400 81.9 106.4 129.7 147.9 170.7 175.2 182.4 221.2 245.8 270.2
A Preferred grammages.
B For use when closer steps are essential.
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D 646
5