1、TAPPI/ANSI T 459 om-13 TENTATIVE STANDARD 1942 SUGGESTED METHOD 1965 OFFICIAL STANDARD 1975 OFFICIAL TEST METHOD 1983 REVISED 1988 REVISED 1993 REVISED 1993 REVISED 2003 REAFFIRMED 2008 REVISED 2013 2013 TAPPI The information and data contained in this document were prepared by a technical committee
2、 of the Association. The committee and the Association assume no liability or responsibility 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
3、 the most recent edition published. Approved by the Standard Specific Interest 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 meth
4、od to safety issues related to such use. The user is responsible for determining 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,
5、 disposal, or both, of chemicals which may present serious health hazards to humans. 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 distrib
6、utors of potentially hazardous chemicals. Prior to the use of this method, the 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
7、 authorities for safe use and disposal of these chemicals. Surface strength of paper (wax pick test) 1. Scope This method, applicable to uncoated and coated papers, is designed to measure the surface strength of paper or its resistance to picking. It is not applicable to loosely felted papers such a
8、s blotters or roofing felts, nor to papers containing materials that soften with heat such as waxes or latex type additives. Light weight papers that lack stiffness may slip under the block during the wax removal step are not suitable for testing by this procedure. 2. Summary In this test, calibrate
9、d sealing waxes with increasing adhesive power are pulled from the surface of the specimens. The highest number of the wax in the series which does not disturb the surface of the paper is the numerical rating of the pick. 3. Significance 3.1 Many printing and converting operations require the surfac
10、es of the paper to have sufficient z-direction strength to give satisfactory results. Since no absolute values are obtained with this method, test results should be correlated with actual performance of the material during the subsequent coating, converting, printing or packaging operation (1). 3.2
11、For coated paper, where a significant portion of the casein or starch coating adhesive has been replaced with a thermoplastic resin, there is very little, if any, correlation between printing press performance and wax test results. T 459 om-13 Surface strength of paper (wax pick test) / 2 The molten
12、 wax forms a stronger bond with the coating containing thermoplastic resin and the resulting pick causes the paper to appear weak, when in fact it is not. 3.2.1 For those sheets containing latex and similar substances, a more direct method employing the actual medium to be applied is recommended. 4.
13、 Definitions 4.1 Pick. A pick occurs when the surface of the paper specimen blisters, breaks, or lifts and/or paper or coating substance adheres to the surface of the wax. 4.2 Critical wax strength number, the average highest numerical designation of the wax that does not disturb the surface of the
14、paper. 5. Apparatus 5.1 Heating device, such as: Bunsen burner, alcohol lamp, propane torch, or electric heat element. 5.2 Wooden block, about 90 40 10 mm (31/2 11/2 3/8in.) having a 30 mm (11/4in.) diameter hole with an edge about 3 mm (1/8in.) from one end. 5.3 Work surface that is smooth, hard, a
15、nd a poor conductor of heat, such as wood. (Glass, metal, or artificially cooled surfaces are unsuitable.) 6. Materials Waxes1, a series of hard-resin, non-oily waxes numbered respectively from 2A to 26A. Each wax is made up according to a specific formula and molded to stick form with a cross-secti
16、onal area of 18 18 mm (11/16 11/16in.). Each higher numbered wax in the series is more adhesive than the previous one. CAUTION: This method involves the use of molten wax. Thus extreme caution should be exercised to avoid the potential of severe burns. 7. Safety This method involves the use of molte
17、n wax. Thus extreme caution should be exercised to avoid the potential of severe burns. The heating procedure may involve the use of an open flame. Be cautious of flammable material in the proximity the flame. 8. Calibration The sealing wax sticks used in this method are calibrated by the manufactur
18、er against retained wax sticks and paper standards. Not only does each wax stick equal the corresponding standard stick, but each will effectively distinguish the surface strength when compared with adjacent wax numbered sticks. The tester can calibrate any series of wax sticks by noting whether the
19、 surface is progressively more ruptured with ascending wax stick numbers and by checking new boxes of waxes against retained wax sticks and/or paper standards. 9. Sampling and test specimens 9.1 Select a number of specimens, usually 10, each 100 100 mm (4 4 in.) or larger, from each test unit of a s
20、ample of paper obtained in accordance with TAPPI T 400 “Sampling and Accepting a Single Lot of Paper, Paperboard, Containerboard, or Related Product,” so that five replicate critical waxes may be determined for each tested surface (wire and felt). 1Names of suppliers of testing equipment and materia
21、ls for this method may be found on the Test Equipment Suppliers list, available as part of the CD or printed set of Standards, or on the TAPPI website general Standards page. 3 / Surface strength of paper (wax pick test) T 459 om-13 9.2 In cases such as single-sided coated graphic arts papers or box
22、boards where the test is to be performed on a single side, select a number of test specimens such that the area is large enough to perform 5 tests with a minimum of 100 mm (4 in.) between test locations. 10. Procedure 10.1 Precondition, condition, and test the specimens in an atmosphere in accordanc
23、e with TAPPI T 402 “Standard Conditioning and Testing Atmospheres for Paper, Board, Pulp Handsheets, and Related Products.” 10.2 Place a test specimen on the work surface. Select a wax stick estimated to have less adhesiveness than will disturb the surface of the specimen. Clean the end with a sharp
24、 blade or if necessary by melting off any paper or coating residue. NOTE 1: Normally, the end of the wax stick will tend to spread out after repeated use. Thus, the wax sticks should be trimmed to maintain their original 18 mm 18 mm size. 10.3 Heat the end in a low flame or by electrical heat elemen
25、t, rotating the stick slowly between the thumb and finger until several drops of melted wax have fallen, but do not let the stick catch fire. Also the molten wax should not “bubble” which indicates wax is too hot. The entire surface should be molten wax. 10.4 Quickly place the melted end of the wax
26、stick on the surface of the paper specimen with firm, but not undue, pressure so that the end spreads out to about 20 mm diameter, and withdraw the fingers immediately, allowing the wax stick to stand vertically on the paper. 10.5 Allow the wax to cool for at least 15 min and not more than 30 min. P
27、lace the wooden block with the hole over the vertical stick of wax so that the stick protrudes through the hole; press the block down firmly with one hand to prevent the paper from wrinkling or tearing, and with the other pull the wax from the sheet with a quick jerk at right angles to the paper sur
28、face. 10.6 Examine both the tip of the wax and the paper specimen under normal reading illumination with no magnification. There must be a definite indication of fibers or coating disturbed to be called a pick or surface rupture. 10.7 If the surface is not ruptured, repeat the test, using the same s
29、pecimen with waxes of ascending numerical order until the surface of the paper specimen blisters, breaks, picks, or lifts. Test a minimum of five specimens on their wire side and five other specimens on their topside, or if not identifiable as such, five each from the two different sides of the pape
30、r. In the case of sheets that have a single side to be evaluated, make 5 tests on the side of interest. 10.8 Record the highest numerical designation of the wax that does not disturb the surface of the paper and average the results on each side that was evaluated to the nearest wax number. Caution:
31、Wax is hot and will burn skin if molten wax comes in contact with hands. 11. Report 11.1 Report as the critical wax strength number (CWSN) the average highest numerical designation of the wax that does not disturb the surface of the paper. 11.1.1 Report the number of tests made on each side as well
32、as the range of highest numerical designation of the wax for the specimens on each side of the paper. 11.2 With coated papers, state whether the picking or lifting occurred on the coating or on the basestock, or both. If desired, include also the degree of surface disturbance with waxes more adhesiv
33、e than for the critical strength. For example, a paper may have a CWSN of 14A, a blister at 16A, a partial fiber pick at 18A, and complete rupture at 20A. 12. Precision 12.1 Repeatability (within laboratory) = 1.98 wax units 12.2 Reproducibility (between laboratories) = 4.0 wax units These values ar
34、e based on Collaborative Testing Service data for samples tested at a mean of 10.64 wax units during the period of July 1989 to May, 1990. 12.3 The user of these precision data is advised that it is based on actual mill testing, laboratory testing, or both. There is no knowledge of the exact degree
35、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 method is routinely used by two or more parties. T 459 om-13 Surface strength of paper (wax pick test) / 4 12
36、.4 The large variation between laboratories is mostly due to operator variation in the heating, application and removal of the wax sticks. 13. Keywords Paper, Paperboard, Coated boards, Surface strength, Pick resistance, Wax pick tests 14. Additional Information 14.1 Effective date of issue: Novembe
37、r 5, 2013. 14.2 Related methods: TAPPI T 514 “Surface Strength of Coated Paperboard” and PAPTAC D-11 (Canada). 14.3 Changes in the 2013 edition include a procedural change to allow for single-side testing, as well as the addition of a safety section. Reference 1. Kirkpatrick, W. A., “The Use of Waxes and Case Testing Ink in Testing Printing Papers,” Paper Trade J. 109 (12): 36 (1939); Tech. Assoc. Papers 22:322 (1939). Your comments and suggestions on this procedure are earnestly requested and should be sent to the TAPPI Standards Department.
