1、T 815 om-12 SUGGESTED MEHTOD 1972 OFFICIAL METHOD 1985 REVISED 1990 REVISED 1995 REVISED 2001 REVISED 2007 REVISED 2012 2012 TAPPI The information and data contained in this document were prepared by a technical committee of the Association. The committee and the Association assume no liability or r
2、esponsibility in connection with the use of such information or data, including but not limited to any liability under patent, copyright, or trade secret laws. The user is responsible for determining that this document is the most recent edition published. Approved by the Standard Specific Interest
3、Group for this Test Method TAPPI CAUTION: This Test Method may include safety precautions which are believed to be appropriate at the time of publication of the method. The intent of these is to alert the user of the method to safety issues related to such use. The user is responsible for determinin
4、g that the safety precautions are complete and are appropriate to their use of the method, and for ensuring that suitable safety practices have not changed since publication of the method. This method may require the use, disposal, or both, of chemicals which may present serious health hazards to hu
5、mans. Procedures for the handling of such substances are set forth on Material Safety Data Sheets which must be developed by all manufacturers and importers of potentially hazardous chemicals and maintained by all distributors of potentially hazardous chemicals. Prior to the use of this method, the
6、user must determine whether any of the chemicals to be used or disposed of are potentially hazardous and, if so, must follow strictly the procedures specified by both the manufacturer, as well as local, state, and federal authorities for safe use and disposal of these chemicals. Coefficient of stati
7、c friction (slide angle) of packaging and packaging materials (including shipping sack papers, corrugated and solid fiberboard) (inclined plane method) 1. Scope 1.1 This method determines the coefficient of static friction of most packaging materials by measuring the angle at which one test surface
8、begins to slide against another inclined surface as the incline is increased at a constant and prescribed rate. 1.2 The test is frequently referred to as slide angle. The coefficient of friction is numerically equivalent to the tangent of that angle. 1.3 TAPPI T 549 describes a horizontal method for
9、 determining static and kinetic friction but is intended for application to printing and writing papers and the procedures are somewhat different. 2. Significance 2.1 The coefficient of friction of packaging materials indicates how packages made from that material will perform in many critical appli
10、cations. A high coefficient of one surface of paper or paperboard (containerboard) to itself means that containers having that surface will tend to resist sliding in unit loads. A low coefficient may indicate potential problems with the packages slipping from the load. 2.2 The coefficient of static
11、friction test is empirical. It describes the condition of that surface at the moment of test. This may or may not relate to the condition of that surface in use. Its condition will depend upon the historical treatment of the surface, especially if frictionizing materials have been used to treat the
12、surface. These materials may be rubbed off in handling downstream. For surfaces treated with frictionizing agents, experience has shown that variability is significantly reduced after the third slide. Coefficient of friction is also significantly affected by contamination with very small amounts of
13、materials which lower the friction such as waxes and other oily materials. As with surfaces treated with frictionizing agents, coefficient of friction test results on surfaces containing waxes or other oily materials also show reduced variability when preliminary conditioning in the form of slides a
14、re made before the results are recorded. Where the surfaces are known to have been treated with a frictionizing agent or suspected to contain wax or oily materials or T 815 om-12 Coefficient of static friction (slide angle) of packaging / 2 and packaging materials (including shipping sack papers, co
15、rrugated and solid fiberboard) (inclined plane method) when the previous history of the packaging material is unknown, test results are not recorded until the third slide. When it is known that the packaging materials being tested are untreated, test results may be recorded on the first slide with l
16、ittle or no loss in accuracy (5). 3. Definitions 3.1 The coefficient of friction is the ratio of the frictional force resisting movement of the surface being tested to the force applied normal to that surface (the weight of the material above that surface). For the inclined plane, the coefficient is
17、 numerically equal to the tangent of the angle of incline. 3.2 The static coefficient is the ratio of the force resisting initial motion of the surface to the normal force. 4. Apparatus 4.1 Timer, stopwatch or electric timer reading in seconds. 4.2 Inclined plane and sled, consisting of the followin
18、g: 4.2.1 Sled, a metal block, rectangular, of size and mass to produce a pressure of 1.4 0.7 kPa (0.2 0.1 psi) with a plane lower surface faced with a foamed rubber or plastic padding, 3mm (1/8 in. thick). While the exact measurements are not critical, dimensions of 90 x 100 mm (3.5 x 4 in.) for the
19、 surface and a mass of 1300 g (2.9 lb) is acceptable. The foamed material on the surface should be compressed by 25% of its original thickness when under a pressure of 85 kPa (12.5 psi). A means for clamping the test specimen to the sled is desirable but not necessary. NOTE 1: Theoretically the coef
20、ficient of friction being a ratio is independent of the normal force being applied (the weight of the sled). However, because paper is a compressible material this theoretical relationship does not hold and the coefficient determined is mildly influenced by the pressure applied. 4.2.2 Inclined plane
21、, a smooth, plane, incompressible surface of suitable material, hinged so that it can be tilted and having a width at least 12.5 mm (0.5 in.) wider than the sled and a length sufficient to permit the sled to move at least 25 mm (1 in.), provided with a clamp at its upper end to fix the test specimen
22、 in place and a bumper stop at its lower end (Fig. 1). All units do not have upper clamps but instead may utilize side clamps or non-slip pads to prevent the bottom sample from moving during testing. 4.2.2.1 Means to smoothly increase the angle of inclination of the plane at a rate of 1.5 0.5/s from
23、 the horizontal through an arc of 45. The motion should be free of vibration. 4.2.2.2 Means to indicate the angle of inclination within 0.5. 4.2.2.3 Means to level the instrument in two directions when the inclined plane is in its horizontal position. 5. Sampling and test specimens 5.1 If the packag
24、ing material being tested is in the form of a lot being tested to determine conformance to specifications, obtain a sample according to TAPPI T 400 “Sampling and Accepting a Single Lot of Paper, Paperboard, Containerboard or Related Product.” Obtain at least 5 samples representative of the material
25、as a whole. Each sample must be large enough to be cut into the two pieces required for each test. 5.2 If the specimens are from a package, carefully cut them from areas which normally come into contact with the next package in unit loads and away from obvious defects or scored areas. 5.3 Identify e
26、ach paper specimen for both direction and surface, viz. MD (machine direction), CD (crosswise direction), felt (top) and wire (bottom) side. For corrugated board, the CD is the direction parallel to the flutes. Do not mark the sheet in the area to be tested. 5.4 The face of the paper or board to be
27、tested will be that side that forms the exterior of the package, normally the top or felt side of the sheet. 5.5 Since paper is anisotropic and the coefficient of friction is particularly so, care must be taken in making the test to orient the surfaces just as they will be in actual use. Therefore i
28、f the layers of packages are to be alternated in palletization, the coefficient should be measured with one surface MD and the other CD. It should also be noted that the coefficient of friction may also be sensitive to the way the fibers are laid down during the papermaking process so that MD and an
29、ti-MD are also frequently significantly different. The procedure spells out that for each test, the piece oriented MD must be reversed 180 for each succeeding measurement and this should be done whatever pattern of orientation is employed. 3 / Coefficient of stating friction (slide angle) of packagi
30、ng T 815 om-12 and packaging materials (including shipping sack papers, corrugated and solid fiberboard) (inclined plane method) Fig 1. Inclined plane. 5.6 Each test unit consists of two specimens. 5.6.1 Cut the smaller specimen to be fixed to the sled a little (ca. 3 mm or 1/8 in.) larger than the
31、base of the sled so that it will extend beyond the bottom edges of the sled. Flexible materials can be folded around the edges of the sled and perhaps clamped to the sled. For heavier grades, for example paperboard (containerboard) it may be expedient to score the specimen on the face opposite that
32、to be tested in the position where it will contact the edge of the sled, so that the sheet can be easily folded to conform to the sled without creating any bulging of the test surface. 5.6.2 Cut another specimen slightly larger to cover the working surface of the inclined plane and long enough in th
33、e direction of slide to permit the required length of slide. NOTE 2: Exercise special care in handling the test specimens because any abnormal contact or rubbing prior to testing may significantly affect the test results. Take care to avoid contamination of the test surface with wax or skin oil. Do
34、not touch the test area with the fingers. Thoroughly clean the specimen cutters used to prepare the test specimens with solvent or detergent prior to preparing the test specimens (1). 6. Conditioning 6.1 Condition and test the specimens in accordance with TAPPI T 402, “Standard Conditioning and Test
35、ing Atmospheres for Paper, Board, Pulp Handsheets and Related Products.” 6.2 Coefficient of static friction can be significantly affected by the sample moisture content. Care should be taken if the samples cannot be properly conditioned as might occur in a production environment. 7. Procedure 7.1 Le
36、vel the plane so that it is horizontal (two directions at 90 to each other) when the inclinometer indicates zero degrees. 7.2 Mount the larger test specimen on the inclined plane with the surface to be tested facing upward. Clamp in place if necessary (see 4.2.2). Attach the other specimen with surf
37、ace to be tested facing downward and rotated 90 to the direction of the specimen on the plane. (The 90 deg. rotation was established to simulate one type of box stacking pattern (interlocking) and as such is referenced as the standard. Other orientations which may be more appropriate to represent ac
38、tual field conditions may be used but are not considered adequate to meet T 815). There should be no obvious looseness or slack in the specimen. Position the sled and its test specimen on top of the other test specimen near the end of the inclined plane that is away from the hinge and stop. T 815 om
39、-12 Coefficient of static friction (slide angle) of packaging / 4 and packaging materials (including shipping sack papers, corrugated and solid fiberboard) (inclined plane method) NOTE 3: Exercise care when placing the sled and test specimen on the test specimen mounted on the inclined plane that th
40、ere is no reverse relative motion of the test specimens. Avoid side to side motion, but this is not normally encountered in the very brief slide used in this test. 7.3 If the end use of the materials has dictated that a different machine orientation is more applicable, record the direction of orient
41、ation of the test samples and include that orientation in the final report (see 9.1). 7.4 Allow a dwell time of 10 s, and then increase the angle of incline at the specified rate of 1.5 0.5/s. Stop the incliner when the sled starts to move and permit the sled to slide to the stop. If it is known tha
42、t no frictionizing treatment has been applied, record this angle at which the sled has begun its slide to the nearest 0.5. Return the inclined plane to its horizontal position. If fractionizing agents have been applied or this condition is unknown, carefully lift the sled and attached specimen and p
43、lace in the original starting position on the inclined plane (in horizontal position). Again after the dwell time of 10 s, repeat the inclination to the start of sliding, let the sled come to a stop, return the incline to horizontal, but make no record of the angle at which sliding begins. For the t
44、hird time, carefully lift the sled and specimen to the starting position, allow it to dwell 10 s and raise the incline to the inception of sliding, record the angle at which sliding begins on this third slide to the nearest 0.5. 7.5 Place the next pair of test specimens on the sled and inclined plan
45、e but this time rotate 180 the specimen that has been the oriented with the MD in the direction of slide. Test as in 7.4. 7.6 Complete the testing of the remaining three test units, reversing the one specimen as in 7.5 for each succeeding measurement. 8. Calculations 8.1 Determine the average angle,
46、 to the nearest 0.5 degree, at which sliding begins for the five determinations. This will be for either the first slide or for the third slide. 8.2 Calculate the coefficient of friction by finding the tangent of this angle in a suitable table of trigonometric functions. 9. Report 9.1 Report the ave
47、rage angle of slide. Also report the orientation of the test specimens and the face of the material tested and report whether the first or third slide was recorded. 9.2 Report the average coefficient of friction calculated from the average angle of slide and report any alternative conditions as in 9
48、.1. 10. Precision 10.1 For the maximum expected difference between two test results, each of which is the average of five test determinations, the following applies only to untreated, uncoated packaging papers (third slide). 10.1.1 Repeatability (within a laboratory) = 6%. 10.1.2 Reproducibility (be
49、tween laboratories) = 15%; in accordance with the definitions of these terms in TAPPI T 1200 “Interlaboratory Evaluation of Test Methods to Determine TAPPI Repeatability and Reproducibility.” 11. Keywords Slide angle, Friction factor, Friction, Packaging materials, Packaging papers, Bag papers, Inclined planes, Paperboard, Container boards, Shipping containers, Multiwall bags. 12. Additional information 12.1 Effective date of issue: April 24, 2012. 12.2 This method is written specifically for the inclined-plane apparatus and is confined to the measurement of st
