1、Designation: D 4446 05Standard 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 (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is designed to evalua
3、te 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
4、and 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/treatmen
6、t 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 determini
8、ng 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 spec
9、ieswhen 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: (
10、1) 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 h
11、umidity 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 l
12、east 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 givespecimen
13、s 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
14、Ponderosa 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
15、amounts 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 May 15, 2005. Published June
16、2005. Originallyapproved in 1995. Last previous edition approved in 2002 as D 4446 02.1Copyright 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 yell
17、owish 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 sw
18、elling 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
19、Samples Tested SimultaneouslyFIG. 2 Single Test Swellometer Tank and One SampleFIG. 3 Single Test Swellometer TankWith One Sample In Place.D44460526.3 Establish adequate records, reference samples and iden-tification to permit independent review and analysis.7. Test Procedure7.1 Cut two adjacent spe
20、cimens, 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 a
21、dditional 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 determin
22、e 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 b
23、eing 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
24、the 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 pe
25、riod 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 t
26、he 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 f
27、ree 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 cham
28、ber 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
29、 accordance 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
30、Tangential 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.D4446053means of the Swellometer (illustra
31、ted 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 th
32、e 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
33、 treated 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 o
34、f 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
35、test. 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. Keywords9.1 anti-swelling; liquid water; water repellentASTM International takes n
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39、dress 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 contacting 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).D4446054
