1、Designation: D 4446 08Standard Test Method forAnti-Swelling Effectiveness of Water-Repellent Formulationsand Differential Swelling of Untreated Wood When Exposedto Liquid Water Environments1This standard is issued under the fixed designation D 4446; the number immediately following the designation i
2、ndicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is designed to evaluat
3、e the effective-ness of water-repellent compositions for retarding dimensionalchanges in coated wood submerged in water. It can also be usedto measure the differential swelling of untreated wood whenexposed to liquid water environments. The compositions testedare designed to be mixed until uniform a
4、nd applied by brush,roller, dip or spray to an exterior wood surface.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use.
5、It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Summary of Method2.1 Wood samples in the form of elongated slats thatrepresent the timber species or product/treatment
6、 combinationto be evaluated are exposed in soak containers. The elongatedslats are immersed in the water-repellent formulation, condi-tioned with appropriate weighing, then subjected to immersionin distilled water for a prescribed period. The untreated slatsomit the immersion in the water-repellent
7、formulation. Theswelling resulting from immersion for the selected time periodis determined by reading a dial gage calibrated in increments of0.025 mm (0.001 in.).2.2 A water repellent efficiency of 60 % is required to passthis test.3. Significance and Use3.1 This test method is useful in determinin
8、g the relativeanti-swelling efficiency of various water-repellent formulationswhen applied to wood. It is the initial means of estimating theability of water-repellent treated wood to perform satisfactorilywhen exposed to liquid water environments.3.2 The swelling differences of untreated wood speci
9、eswhen subjected to water immersion can also be determined bythis test method.3.3 This method is a basic screening test and thus providesan initial determination of the anti-swelling efficiency of waterrepellents. It is a qualitative method designed to provide areproducible means of establishing: (1
10、) the anti-swelling effi-ciency of water-repellent formulations, and (2) the relativeswelling of untreated wood species when both are exposed toliquid water environments.4. Apparatus4.1 Conditioning Room or Chamber, having a controlledtemperature of 23 6 2C (73.5 6 3.5F), and a controlledrelative hu
11、midity of 50 6 5 %. This room is used to establisha uniform moisture content in the test specimens. In all studiesthe temperature and relative humidity selected by the investi-gator must be stated and must remain constant throughout agiven conditioning and test period.4.2 Balance, sensitive to at le
12、ast 0.01 g.4.3 Treating Tank (Fig. 1).4.4 Swellometer, as illustrated in Fig. 2, Fig. 3, and Fig. 4.5. Test Specimens5.1 Wood used for these tests must be straight-grained,flat-sawn, clear, kiln-dried Ponderosa pine sapwood or othersuitable species. Cut the parent boards in a manner to givespecimens
13、 6 mm (14 in.) in the longitudinal dimension, 112 in.(38 mm) in the radial dimension, and 254 mm (10 in.) in thetangential dimension. Cut with a sharp, fine-toothed saw toobtain as smooth a surface as possible without sanding.Number each specimen for identification and reference.5.1.1 Selection of P
14、onderosa pine sapwood can be assuredby the following quick chemical test: (1) prepare a solution of5 g of benzidine in 25 g of hydrochloric acid and 970 g ofwater, and (2) prepare a second solution consisting of a 10 %concentration of sodium nitrite in water. When the test is to bemade, pour equal a
15、mounts of the two solutions together and1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.42 on Architectural Coatings.Current edition approved June 1, 2008. Published July 2
16、008. Originally approvedin 1995. Last previous edition approved in 2005 as D 4446 05.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.then apply to the wood surface by means of brushing ordipping. The sapwood immediately shows a yello
17、wish color,while the heartwood turns dark red-brown. The colors remaindistinct after drying.5.2 Determine the swelling of an untreated specimen fromeach parent board before testing begins. Do this by equilibrat-ing the specimen in accordance with 7.1 and then testing inaccordance with 7.5.1. The swe
18、lling shall not be less than 8.25mm (0.325 in.). See Table 1.6. Formulations6.1 Treat the test specimens with the ready-to-use formula-tion as advocated by the manufacturer of the formulation.6.2 Test, experimental or control formulations may be addedto the test as desired.FIG. 1 Treating TankFive S
19、amples Tested SimultaneouslyFIG. 2 Single Test Swellometer Tank and One SampleFIG. 3 Single Test Swellometer TankWith One Sample In Place.D44460826.3 Establish adequate records, reference samples and iden-tification to permit independent review and analysis.7. Test Procedure7.1 Cut two adjacent spec
20、imens, both either tangentially orlongitudinally, from each board. Specimen pairs from tendifferent boards (20 test specimens in all) make a set (inaccordance with 7.3 and 7.4) for testing the water-repellency ofone formulation at one retention level. Each additional reten-tion level requires ten ad
21、ditional samples. Store the testspecimens with space between each one on a raised screen orrack in the conditioning room or chamber until they reachconstant weight as determined by a uniform weight over a 48-hperiod.7.2 In comparing different water-repellent formulations, it isnecessary to determine
22、 the quantity of formulation picked upand retained by the test specimen. If the specimens are weighedbefore treatment and again immediately after being dipped inthe water-repellent formulation and then blotted, the differenceis the weight of the formulation absorbed. Then, if reweighedjust before be
23、ing placed in the swellometer, the differencebetween the blotted weight and the final weight is the weight ofthe material actually retained by the specimen.7.3 First Test:7.3.1 Maintain the formulation to be tested at a minimumtemperature of 21C (70F) and thoroughly mix immediatelybefore immersing t
24、he test specimens.7.3.2 Fully immerse in the Treating Tank (Fig. 1) five of theten test specimens (one from each board) in the formulation tobe tested. The immersion time for solvent-based formulationsshall be 30 s. Because of the small size of the specimens (6 mm(14 in.) thick) a 30-s immersion per
25、iod is adequate forformulation pickup. This 30-s immersion period will reflectappropriate screening test results, but is not intended to reflectthe proper treatment time for use on commercial products. Theimmersion time for water-based formulations shall be 3 min.Treat the test specimens while in th
26、e conditioning room/chamber or within 30 s after removal from the conditioningroom/chamber. Five untreated specimens, one from each of theboards, serve as controls.7.3.3 Place both the five treated and the five untreatedspecimens separately on a raised screen or other suitable rackthat will allow fr
27、ee access of air to them, and place thespecimens in the conditioning room or chamber. After 24 h,remove all specimens from the conditioning room or chamberand allow them to volatilize under normal laboratory condi-tions for 3 days. Then place all ten specimens back into theconditioning room or chamb
28、er until they reach constantweight.7.4 Second Test:7.4.1 Pour the formulation remaining after treating (7.3.2)into a sealable glass container and allow to stand for 2 monthsat a temperature of 21 to 38C (70 to 100F). After this2-month period, decant and again test the formulation withoutshaking in a
29、ccordance with 7.3. The formulation must passboth tests.7.5 Testing the Water-Repellency:7.5.1 Compare the swelling of the untreated controls withthe swelling of the matched treated specimens after each hasbeen submerged in distilled water. Measure the swelling byFIG. 4 SwellometerTABLE 1 Natural Ta
30、ngential Swelling of Selected SpeciesASpeciesTangentialSwelling,%Pine, ponderosa 6.2southern yellow 7.5Oak, red 9.5white 10.5Maple 8.3Beech 11.9Douglas-fir 7.6ASource: “Wood Handbook,” Agriculture Handbook No. 72, USDA, ForestService, Washington, DC, 1974.D4446083means of the Swellometer (illustrate
31、d in Fig. 2, Fig. 3, and Fig.4). Insert a specimen in the guides of the swellometer, placedso that one end bears firmly on the adjusted base and the otherend contacts the plunger of the dial. Take a reading of the dialbefore immersing the sample in the water. Arrange the instru-mented sample in the
32、container of distilled water maintained at24 6 3C (75 6 5F) so that the specimen is completelysubmerged (but the dial and dial stem are dry) for 30 min. Atthe end of the 30-min period, take a second dial reading andnote the difference. Test the group of five untreated controlsand the group of five t
33、reated specimens separately using freshdistilled water for each group.8. Evaluation of Results8.1 Results from the first (ten samples, that is, five pairs oftreated specimens and controls) and second tests (ten samples)shall be separately recorded and computed. The differencebetween the swelling of
34、each treated specimen and the swellingof its matching untreated control specimen is divided by theswelling of the untreated control specimen and multiplied by100. The average of the five percentages calculated for eachtest represents the percent effectiveness of the water-repellentformulation per te
35、st. The average of the results from both testsrepresents the final percent of water-repellent effectiveness ofthe formulation.8.2 A minimum water-repellent efficiency of 60 % is re-quired to pass this test method.9. Precision and Bias29.1 The precision of this test method is based on aninterlaborato
36、ry study of Test Method D 4446 - 05, conducted in20062007. Each of six laboratories tested the effectiveness offour different water repellent formulations on 10 in. wafers. Sixlaboratories obtained two replicate test results for each mate-rial. See Table 2.9.1.1 RepeatabilityTwo test results obtaine
37、d within onelaboratory shall be judged not equivalent if they differ by morethan the “r” value for that material; “r” is the intervalrepresenting the critical difference between two test results forthe same material, obtained by the same operator using thesame equipment on the same day in the same l
38、aboratory.9.1.2 ReproducibilityTwo test results shall be judged notequivalent if they differ by more than the “R” value for thatmaterial; “R” is the interval representing the difference be-tween two test results for the same material, obtained bydifferent operators using different equipment in diffe
39、rent labo-ratories.9.1.3 Any judgment in accordance with these two state-ments would have an approximate 95 % probability of beingcorrect.9.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is
40、 being made.9.3 The precision statement was determined through statis-tical examination of 47 results, from six laboratories, on fourmaterials. These four materials were described as the follow-ing:Material A: 8.4 % solids oil based clear water repellentMaterial B: clear 5 % paraffin wax petroleum d
41、istillate solutionMaterial C: 10 % solids water based clear water repellentMaterial D: 39 % solids paraffin wax emulsion9.3.1 To judge the equivalency of two test result, it isrecommended to choose the water repellent material closest incharacteristics to the test material.10. Keywords10.1 anti-swel
42、ling; liquid water; water repellentASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are expressly advised that determination of the validity of any such patent rights, and the risk
43、of infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this
44、 standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake y
45、our views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by c
46、ontacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).2Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D011143.TABLE 2 10 in. Wafer Swelling (%)Fluid AverageRepeatabilityStandardDeviationReproducibilityStandardDeviationRepeatabilityLimitReproducibilityLimitx sr sR r RA 76.20 1.80 2.96 5.03 8.30B 63.17 1.92 3.50 5.36 9.80C 73.84 3.25 4.10 9.09 11.49D 9.45 1.25 3.71 3.50 10.38D4446084
