1、Designation: E2407 04 (Reapproved 2009)Standard Test Method forEffectiveness of Defoaming Agents1This standard is issued under the fixed designation E2407; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision.
2、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 describes a qualitative method for theevaluation of liquid defoaming agents used to control undesir-able foam in dil
3、ute, aqueous surfactant solutions. This labora-tory test method may be applied to aqueous systems containingadditional components, such as agricultural chemicals. Thismethod is described using SI units1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are
4、included in thisstandard.1.3 This standard method does not purport to address all ofthe safety problems, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitati
5、ons prior to use.2. Referenced Documents2.1 ASTM Standards:2E1116 Test Method for Emulsification Characteristics ofPesticide Emulsifiable ConcentratesE1519 Terminology Relating to Agricultural Tank MixAdjuvants3. Terminology3.1 Definitions:3.1.1 defoaming agent, na material that eliminates orsuppres
6、ses foam in the spray tank. E15193.1.2 durability, adjthe degree to which a defoamingagent remains effective over time under foam generatingconditions3.1.3 foaming agent, na material that increases the vol-ume or stability of the foam formed in a spray mixture4. Summary of Test Method4.1 Foam is gen
7、erated in a high-speed blender with a dilutesurfactant solution prior to addition of a defoaming agent to theblender cup. After 1 min of gentle agitation and five min ofrest, any remaining foam is measured. The ability of thedefoaming agent to reduce foam is expressed as percent foamreduction.5. Sig
8、nificance and Use5.1 This test is designed to determine the ability of amaterial to reduce or eliminate undesirable foam that can begenerated during the mixing and application of agriculturalchemicals in dilute aqueous mixtures.5.2 This method is useful for testing liquid defoamingagents, such as “s
9、ilicone emulsion” or “organic” type defoam-ing agents. In principle, it might also be used to test dryantifoam agents with minor modifications to the procedure.5.3 This method could be employed to determine therelative effectiveness of one defoaming agent versus another. Itis left to the user of thi
10、s method to interpret the results withrespect to the actual field use of the defoaming agents tested.5.4 This method assumes that the defoaming agent beingtested has sufficient durability to maintain its activity for theduration of the test.5.5 Sodium lauryl ether sulfate as the foaming agent isdesc
11、ribed in Section 7, Reagents. If desired the user of this testmethod may select an alternative suitable foaming agent.6. Apparatus6.1 Blender The blender should have a removable 1.2 literglass cup equipped with a removable stainless steel bladeassembly (Note 1), and a motor base capable of a no-load
12、speed of 22 000 rpm.NOTE 1The blade assembly should turn freely by hand. If it does not,replace the assembly before using this test method.6.1.1 Blender assembly Plug the power supply cord of theblender into the power outlet of a variable transformer with a0 to 120V output. Plug the transformer into
13、 a 115V groundfault protected (GFCI) power source. Using water, an elec-tronic balance, and a marking pen, mark 50 mL graduations onthe glass blender cup, from 200 to 1000 mL. This is easily done1This test method is under the jurisdiction of ASTM Committee E35 onPesticides and Alternative Control Ag
14、ents and is the direct responsibility ofSubcommittee E35.22 on Pesticide Formulations and Delivery Systems.Current edition approved Oct. 1, 2009. Published November 2009. Originallyapproved in 2004. Last previous edition approved in 2004 as E2407 04. DOI:10.1520/E2407-04R09.2For referenced ASTM stan
15、dards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
16、PA 19428-2959, United States.by placing the blender cup on the balance, taring the balance,then adding 50 g water and marking the water level on theexterior of the cup. Continue adding 50 g water at a time andmarking the water level until the cup contains 1000 g. See Fig.1.6.2 Electronic balance acc
17、urate to 0.01 g,6.3 Stopwatch, and6.4 Disposable polyethylene pipet, 7 mL volume or equiva-lent.7. Reagents7.1 Defoaming agentmaterial to be tested.7.2 Hard water stock Prepare 3 L of 342 ppm hard wateras described in Test Method E1116.7.3 Surfactant solution Prepare 3 L of 0.1 % sodiumlauryl ether
18、sulfate (SLES) solution in 342 ppm hard water.7.3.1 Dissolve5gofsodium lauryl ether sulfate (60 %active solution) in 3 L 342 ppm hard water. This will create asolution of 1 g/l of active surfactant. If 60 % SLES is notavailable, adjust the amount used such that the final surfactantsolution contains
19、0.1 % SLES.8. Procedure8.1 Equipment check8.1.1 Assemble the apparatus as described in 6.1.8.1.2 Generate foam as described below in 8.2-8.5.8.1.3 Observe the foam over the next 5 min. The foam willseparate into two layers (foam and liquid) but the total volumeof the foam and liquid should not decre
20、ase by more than about25 mL during this period. Significant loss of foam suggests theblender cup may have residual antifoam present. In this event,wash the blender cup with detergent and thoroughly rinse, thenrepeat steps 8.1.1-8.1.3 before continuing with the method.8.2 Add 250 mL of the surfactant
21、 solution to the blendercup. Cover the blender cup and place it securely on the blenderbase.8.3 After checking that the transformer is in the “off”position, switch the blender speed control to “high”.8.4 Start the stopwatch and smoothly accelerate the blenderblades by turning the variable power supp
22、ly from 0 to 100 %over a period of 2-4 s.8.5 After 30 s has elapsed, stop the blender by turning thetransformer power to 0.FIG. 1 Typical Setup Showing Power Supply, Blender Assembly, and Foam.E2407 04 (2009)28.6 Allow the foam and liquid to separate for 3 min. Recordthe foam volume to the nearest 2
23、5 mL by subtracting thevolume of the liquid layer from the total volume of liquid andfoam in the blender cup. This will be the “initial foam” readingused in 9.1 to calculate “foam reduction, %”. Clear and resetthe stopwatch.8.7 Remove the blender cup cover and add 200 ppm ofdefoaming agent to the ce
24、nter of the cup (Note 2).NOTE 2Most defoaming agents are not 100 % active material. There-fore it is helpful to know the activity of the material being tested and thenadjust the amount added accordingly. For example, if testing a 10 % activedefoaming agent, it would be necessary to add 0.5g to achie
25、ve 200 ppmin 250 mL of surfactant solution.8.8 Start the stopwatch and use the transformer control togive the blender just enough power such that the upper surfaceof the foam begins to move. This will be between 15 % and20 % of the transformer maximum power output, depending onthe age and condition
26、of the blender base and cup assembly.8.9 Continue gentle mixing for 60 s, then shut off power tothe blender but allow the stopwatch to continue to run.8.10 After 6 min has elapsed on the stopwatch, record theending foam volume by measuring the total volume (liquidplus any remaining foam) to the near
27、est 25 mL and subtractingthe volume to the nearest 25 mL of liquid under any remainingfoam.8.11 Dispose of the used surfactant/defoaming agent mix-ture properly and thoroughly clean the test apparatus to preventcarryover of defoaming agent or surfactant to the next deter-mination.9. Calculation9.1 S
28、ee equation below:fr % 5100ifv efv!ifv(1)Where:fr = foam reductionifv = initial foam volumeefv = ending foam volume10. Report10.1 Report the following information:10.1.1 Foaming agent and concentration10.1.2 Defoaming agent- description and amount used10.1.3 Foam reduction, %11. Precision and Bias11
29、.1 Repeatability and reproducibilityfor this methodwere determined using three commercially available siliconedefoaming agents. Repeatability was determined according toASTM International guidelines.3DefoamingagentMean foamreduction, %95%Confidencelimits, %Standarddeviation“A” 92.3 1.4 0.58“B” 95.7
30、2.9 1.15“C” 91.7 1.4 0.5811.2 Reproducibilitywas evaluated with the same threedefoaming agents by five laboratories and is presented in thetable below. Although data are not presented here, largerstandard deviations are to be expected in cases where thedefoaming agent provides low to moderate levels
31、 of foamcontrol.DefoamingagentMean foamreduction, %95%Confidencelimits, %Standarddeviation“A” 90.7 3.55 2.86“B” 94.4 2.87 2.31“C” 93.0 5.20 4.1911.3 Biascannot be determined for this test method be-cause no accepted reference material or reference value exists.12. Keywords12.1 antifoam; defoam; defo
32、aming agent; foam; foam con-trol agent; pesticide; silicone antifoam; surfactantASTM 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 val
33、idity of any such patent rights, and the riskof 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 com
34、ments are invited either for revision of this 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
35、 not received a fair hearing you shouldmake your 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
36、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).3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report E35-1001.E2407 04 (2009)3
