1、Designation: E 2407 04Standard Test Method forEffectiveness of Defoaming Agents1This standard is issued under the fixed designation E 2407; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in pare
2、ntheses 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 describes a qualitative method for theevaluation of liquid defoaming agents used to control undesir-able foam in dilute, aqueous su
3、rfactant 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 This standard method does not purport to address all ofthe safety problems, if any, associated with its use. I
4、t 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. Referenced Documents2.1 ASTM Standards:2E 1116 Standard Test Method for Emulsification Character-istics of Pesticide Em
5、ulsifiable ConcentratesE 1519 Standard Terminology Relating toAgricultural TankMix Adjuvants3. Terminology3.1 Definitions:3.1.1 defoaming agent, na material that eliminates orsuppresses foam in the spray tank. E 15193.1.2 durability, adjthe degree to which a defoamingagent remains effective over tim
6、e 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 generated in a high-speed blender with a dilutesurfactant solution prior to addition of a defoaming agent to theblender
7、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. Significance and Use5.1 This test is designed to determine the ability of amaterial to reduce or eliminate undesirable f
8、oam 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 “silicone emulsion” or “organic” type defoam-ing agents. In principle, it might also be used to test dryantifoam agents
9、 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 this method to interpret the results withrespect to the actual field use of the defoaming agents tested.5.4 This method
10、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 isdescribed in Section 7, Reagents. If desired the user of this testmethod may select an alternative suitable foaming agent
11、.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-loadspeed of 22,000 rpm.NOTE 1The blade assembly should turn freely by hand. If it does not,replace the assembly before u
12、sing 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 120 V output. Plug the transformer into a 115V groundfault protected (GFCI) power source. Using water, an elec-tronic balance, and a marking pen, mark 50 m
13、L graduations onthe glass blender cup, from 200 to 1000 mL. This is easily doneby 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 con
14、tains 1000 g. See Fig.1.1This test method is under the jurisdiction of ASTM Committee E35 onPesticides and Alternative Control Agents and is the direct responsibility ofSubcommittee E35.22 on Pesticides Formulations and Delivery Systems.Current edition approved Oct. 1, 2004. Published November 2004.
15、2For referenced ASTM standards, 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
16、C700, West Conshohocken, PA 19428-2959, United States.6.2 Electronic balance accurate 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 Te
17、st Method E 1116.7.3 Surfactant solution Prepare 3 L of 0.1 % sodiumlauryl ether 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 nota
18、vailable, adjust the amount used such that the final surfactantsolution contains 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 lay
19、ers (foam and liquid) but the total volumeof the foam and liquid should not decrease 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 ste
20、ps 8.1.1-8.1.3 before continuing with the method.8.2 Add 250 mL of the surfactant 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 stopw
21、atch and smoothly accelerate the blenderblades by turning the variable power supply 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 0.8.6 Allow the foam and liquid to separate for 3 min. Recordthe foam volume to the nearest 25 mL
22、by subtracting thevolume of the liquid layer from the total volume of liquid andFIG. 1 Typical Setup Showing Power Supply, Blender Assembly, and Foam.E2407042foam in the blender cup. This will be the “initial foam” readingused in 9.1 to calculate “foam reduction, %”. Clear and resetthe stopwatch.8.7
23、 Remove the blender cup cover and add 200 ppm ofdefoaming agent to the center 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
24、 a 10 % activedefoaming agent, it would be necessary to add 0.5g to achieve 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
25、 the transformer maximum power output, depending onthe age and condition 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
26、by measuring the total volume (liquidplus any remaining foam) to the nearest 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 def
27、oaming agent or surfactant to the next deter-mination.9. Calculation9.1 See 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- de
28、scription and amount used10.1.3 Foam reduction, %11. Precision and Bias11.1 Repeatability and reproducibilityfor this methodwere determined using three commercially available siliconedefoaming agents. Repeatability was determined according toASTM International guidelines.3DefoamingagentMean foamredu
29、ction, %95%Confidencelimits, %Standarddeviation“A” 92.3 1.4 0.58“B” 95.7 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 e
30、xpected in cases where thedefoaming agent provides low to moderate levels 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 m
31、aterial or reference value exists.12. Keywords12.1 antifoam; defoam; defoaming 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. U
32、sers of this standard are expressly advised that determination of the validity 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 eve
33、ry five years andif not revised, either reapproved or withdrawn. Your comments 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 techn
34、ical committee, which you may attend. If you feel that your comments have 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 Conshohock
35、en, 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).3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:E35-1001.E2407043
