ANSI T 569 OM-2014 Internal bond strength (Scott type).pdf

1、TAPPI/ANSI T 569 om-14 PROVISIONAL METHOD 2000 OFFICIAL TEST METHOD 2007 CORRECTION 2007 REVISED 2009 REVISED 2014 2014 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 respon

2、sibility 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 Group

3、 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 determining tha

4、t 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 humans.

5、 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 user

6、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. Internal bond strength (S

7、cott type) 1. Introduction Printing, converting and many product applications subject paper and paperboard to impulses, impacts and shock loads into or out of the plane of the sheet. These can cause structural failures such as surface picks, blistering or delaminations within the interior of the she

8、et. The common denominators of these failures are a) the high velocity of the impact loads b) the short time period during which the material is stressed, frequently one to a few hundred milliseconds, and c) the planar nature of the resultant sheet failure. Test results from this method may correlat

9、e with product failures of this type. 2. Scope 2.1 This method defines a test that measures the energy required to rapidly delaminate a sheet-type specimen. The “Z” directional rupture is initiated by the impact of a pendulum having both a controlled mass and a controlled velocity that exceeds 6000

10、times the velocity of tensile strength and other dead-weight testers. The geometry of the apparatus causes the tensile stress to be rotational in nature with negligible shear stress on the specimen. 2.2 The method is suitable for both single and multi-ply paper and paperboard, including coated sheet

11、s and those that are laminated with synthetic polymer films. 2.3 Because sample preparation entails pressing double-coated tape to both sides of the test specimen under relatively high pressures, this method may not be suitable for testing high strength handsheets or low basis weight (below 40 g/m2)

12、, porous, soft or low-density materials, such as tissue. Limitations include materials that permit significant migration of the tapes adhesive into the sample with potential tape-to-tape bonding, or materials that could be structurally damaged or collapse during the press cycle. 2.4 To determine the

13、 applicability of the test method, it is important to visually inspect both sides of a set of at least 10 delaminated samples. The ability to rupture a sample within the measurement range of the instrument is an insufficient criterion. For interpretations of observations, see Section 9.2. 2.5 Becaus

14、e energy is absorbed during the elongation and stretching of the samples fiber network prior to rupture, this internal bond test responds to the semi-elastic nature of paper and paperboard. The test is a measurement of strain energy per unit sample area, which is proportional to the area under the s

15、tress-strain curve. Strength measurements by this method do not correlate with “Z” direction tensile strength tests (ZDT) that measure the maximum (peak) stress in T 569 om-14 Internal bond strength (Scott type) / 2 a slow, constant rate of elongation or dead-weight rupture. Also, the constant rate

16、of elongation specified in TAPPI T 541 “Internal Bond Strength of Paperboard (z-Direction Tensile),” (ZDT) and “X” and “Y” plane tensile tests per TAPPI T 494 “Tensile Breaking Properties of Paper and Paperboard (Using Constant Rate of Elongation Apparatus),” is several orders of magnitude less than

17、 the rate attained in this method. 3. Summary A sandwich consisting of double-coated tape, the paper specimen, and double-coated tape is pressed between a flat metal anvil and an aluminum platen as shown in Figure 1. A pendulum impacts the top inside surface of the platen, causing it to rotate and s

18、plit the paper specimen in the thin, “Z” direction (see Figure 2). The energy absorbed in rupturing the sample is computed by measuring the peak excess swing of the pendulum. The strength equation parameters include a) the potential energy of the latched pendulum, b) the peak excess swing, c) the en

19、ergy required to accelerate a bare sample angle away from the pendulum, d) frictional losses, and e) internal vibration losses within the pendulum. 4. Significance 4.1 Internal bond strength as defined in this method is indicative of the serviceability and processibility of many types of paper and p

20、aperboard. These include printing papers, cover, label, release, linerboard, carton, carrier, newsprint and others. Test results often correlate with high-speed surface and internal structural failures encountered in both printing and converting operations. Fig. 1. Sandwich consisting of double-coat

21、ed tape, the paper specimen, and double-coated tape is pressed between a flat metal anvil and an aluminum platen Fig. 2. Positioning of the specimen sandwich, anvil, and platen so that the pendulum strikes at the center of percussion of the platen when the center of oscillation (rotational axis) is

22、at the outside corner of the right angle of the platen. 3 / Internal bond strength (Scott type) T 569 om-14 4.2 Some fiber processing and papermaking characteristics can also be correlated with this type of internal bond strength test. These include extent of refining, machine speed, pressing, inter

23、ply bonding in multiple headbox operations, and furnish composition such as long-to-short fiber mix, recycled content and the effect of dry strength additives. The test responds to both individual fiber strength characteristics and to the degree of interfiber bonding, but does not isolate and distin

24、guish between these factors. 4.3 The combination of internal bond strength data with other TAPPI test methods can provide additional strength and processibility information. An example is the combination with porosity data derived from TAPPI T 460 “Air Resistance of Paper (Gurley Method)” or TAPPI T

25、 547 “Air Permeance of Paper and Paperboard (Sheffield Method)” to predict blistering tendencies for coated web offset papers. 5. Apparatus and materials 5.1 A multiple specimen preparation station capable of pressing five 25.4 25.4 mm (1.00 inch 1.00 inch) samples, the ability to accommodate specim

26、ens of varying caliper up to 1.25 mm (0.050 inches) thick, with optional clamping pressures on the specimen from 345 kPa (50 psi) to 1034 kPa (150 psi) in at least 345 kPa (50 psi) increments. Pressure control shall be within 21 kPa (3 psi) at the most commonly used clamping pressure of 690 kPa (100

27、 psi) and within 34 kPa at the 1034 kPa (5 at the 150 psi) level. A strongback is a component of the preparation station designed to temporarily retain and align the five aluminum platens and prevent their deflection during sample pressing. 5.2 A pendulum mounted on a pedestal, with an axle supporte

28、d at two points on ball or similar low-friction bearings, and whose center of gravity is located 127 0.6 mm (5.00 0.025 inches) from the centerline of the axle. The pendulum should be free to rotate from a horizontal position through at least a 180 swing and the impact ball on the pendulum shall str

29、ike the aluminum platen (see Section 5.4) when it reaches the vertical 90 point in its swing. The resultant 5.00-inch drop in the center of gravity thereby determines the velocity of the pendulum at impact. If weights are added to the pendulum to extend its range, they must be positioned so that the

30、 center of gravity is not altered. In addition, if adding weights alters the center of percussion of the pendulum, this factor must be reflected in the high-range calibration for the instrument. NOTE 1: For additional information regarding differences between manual and automated instruments, see Se

31、ction 13.3. 5.3 A means for holding the pendulum in a horizontal position with provision for instantaneous release. 5.4 A stationary anvil (base) and a separable aluminum platen (sample angle) that is a right angle in cross section. The specimen sandwich, anvil and platen are held stationary on a sa

32、mple stage and positioned so that the pendulum strikes at the center of percussion of the platen when the center of oscillation (rotational axis) is at the outside corner of the right angle of the platen. See Figure 2. NOTE 2: The physical properties of aluminum vary with different alloys thus affec

33、ting the coefficient of restitution between the aluminum angle piece and the steel sphere impact point on the pendulum. It is recommended to use only aluminum angle pieces supplied by the manufacturer of the instrument and designated for use on that instrument. Do not mix aluminum plates between ins

34、truments. 5.4.1 Worn and blemished platens can produce measurement errors of 15% and greater. 5.5 A means of mechanically or electronically registering the peak angular swing of the pendulum after it is released and after it swings beyond the vertical (plumb) position. 5.6 A means to convert a measu

35、rement of the peak angular swing of the pendulum to internal bond strength and provide a visual display of this value. This non-linear calculation may be done with a mechanical scale and friction pointer or electronically with a digital computer. The minimum range of the instrument should be 0 - 525

36、 joules/m2(0 250 10-3ft-lb/in2). 5.7 An optional means to extend the range of the instrument. This may be done by changing the complete pendulum, adding weights to the pendulum or reducing the surface area of the test specimen by a percentage not exceeding 40%. 5.8 A specimen cutter for cutting spec

37、imens 25.4 mm (1.00 in.) wide with straight parallel sides within 0.1 mm (0.004 inches) and long enough for alignment in the specimen preparation station (see tolerances in Section 7.3). 5.9 A knife or multi-blade cutting apparatus for separating and trimming the five specimens to obtain edges witho

38、ut overlaps. The appropriate blade width is determined by the spacing of the anvils in the specimen preparation station and is specified by the apparatus manufacturer as either .025 or .038 cm (.010 or .015 in.). 5.10 Double-coated paper tape 25.4 0.8 mm (1.00 0.03 in.) wide with a release liner. Th

39、e tape should exhibit a minimum adhesion to stainless steel of 45 oz/in. width when tested per ASTM D 3330, and should have a T 569 om-14 Internal bond strength (Scott type) / 4 nominal thickness of 0.15 mm (see cautionary warning in Section 5.6.1). The 3M 410M tape is an example of a tape which com

40、plies with these specifications. However, other tapes complying with these specifications should work equally well. 5.10.1 Although manufacturers quote a shelf life of one year for rubber based tapes, there can be a significant loss of tack after 6 months. Tape should be kept cool and dry by storing

41、 in an air-conditioned atmosphere, preferably at 70F and 50% relative humidity. Tapes with ridges and gaps that indicate a loosely wound roll will dry out rapidly and exhibit low tack. It may be necessary to strip back and discard two to three meters of an older or loosely wound roll to reach a laye

42、r of acceptable tape. 5.11 A solvent such as isopropyl alcohol for removing adhesive residue from the anvils and platens. 6. Calibration 6.1 For both mechanical and electronic instruments, it is important to mount the instrument on a rigid bench or table and carefully level it by means of its adjust

43、able feet. Leveling is most accurately done with a 7.5 cm or longer machinists level rather than relying on the limited resolution provided by the small circular levels mounted on commercial instruments. Level the instrument both side-to-side and front-to-rear using either the sample stage or the ca

44、libration weight slide as a reference surface in accordance with the instrument manufacturers instructions. 6.2 Pendulums of multi-piece construction must be checked for structural integrity by gently attempting to twist the assembly along its length, perpendicular to its rotational axis (axle). If

45、the lower portion of the pendulum is even slightly loose with respect to the main body, internal vibration losses can affect proper calibration and the entire pendulum assembly should be replaced. 6.3 Latch, then release the pendulum to establish a free-swing calibration point in accordance with the

46、 instrument manufacturers instructions. The angular difference between the “calibration” line and “zero”on the scale for mechanical instruments or the specific “free swing number“ and “zero” on the scale for the electronic instruments represents the energy required to accelerate a bare aluminum plat

47、en away from the pendulum. This energy factor is thereby removed from the strength equation relating the pendulums peak angular position to the energy required to rupture a sample. 6.4 For mechanical instruments, establishing a proper free swing by following manufacturers instructions,. 6.5 For elec

48、tronic instruments, the readout for the plumb pendulum position should be adjusted in accordance with the manufacturers instructions. The free swing value should then be re-checked and re-adjusted if necessary. 6.6 Test the calibration test weights, if provided with the instrument, by impacting with

49、 the pendulum in accordance with the manufacturers instructions. Acceptable tolerances for the test weight readings are defined by the manufacturer. After impact, it is important to catch the flying test weights so that their surfaces are not damaged by falling on some hard surface. 7. Sampling and test specimens 7.1 Obtain a sample in accordance with TAPPI T 400 “Sampling and Accepting a Single Lot of Paper, Paperboard, Containerboard or Related Product.” 7.2 Precondition, then condition the sample in accordance with TAPPI T 402 “Standard Condition