1、 CEN EN*IS0*9455- 3 94 3404589 0087383 204 BRITISH STANDARD BS EN IS0 9455-3 : 1995 Soft soldering fluxes - Test methods Part 3. Determination of acid value, potentiometric and visual titration methods The European Standard EN IS0 9455-3 : 1994 has the status of a British Standard UDC 621.791.35.048
2、 : 543,241.25 : 543.852.1 I Cooperating organizations Standards Board and comes into Amd. No. Date effect on 15 February 1995 O BSI 1995 The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of th
3、e following countries: lkxt affected Austria Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Oesterreichisches Normungsinstitut Institut belge de normalisation Dansk Standard Suomen Standardisoimisliit
4、o, r. y. Association franaise de normalisation Deutsches Institut fr Normung e.V. Hellenic Organization for Standardization Technological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-in
5、stituut Norges Standardiseringsforbund Instituto Portugus da Qualidade Asociacin Espaola de Normalizacin y Certificacin Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution The following BSI references relate to the work on this standard: Committee
6、 reference NFMi27 Draft for comment 90/46341 DC ISBN O 580 22884 3 CEN EN*ISO*9455- 3 94 3404589 O089385 087 m BS EN IS0 9455-3 : 1995 Contents Cooperating organizations National foreword Foreword Method 1 Scope 2 Normative references 3 4 Method A: Potentiometric titration method Method B: Titration
7、 method with visual end-point page Inside front cover i 2 3 3 3 3 5 5 Precision 6 6 Rst report 6 Annex ZA (normative) Normative references to international publications with their relevant European publications National annex NA (informative) Committees responsible Inside back cover National forewor
8、d This British Standard has been prepared under the direction of the Non-ferrous Metals Standards Policy Committee and is the English language version of EN IS0 9455-3 1994 Soft solder.ing.fluxes - %t methods - Part 3: Determination of acid value, potentimtric and visual titration methods, published
9、 by the European Committee for Standardization (CEN). It is identical with IS0 9455-3 : 1992 Soft soldemngfluxes - kst methods - Part 3: Determination of acid value, potentiometric and visual titration methods, published by the International Organization for Standardization (ISO). Textual error. Whe
10、n implementing the English language version of EN IS0 9455-3 as the national standard, the textual error given below was discovered. It has been reported to CEN. In the foreword, the name of ISOlE 44 should be Welding and allied processes. Compliance with a British Standard does not of itself confer
11、 immunity from legal obligations. i CEN EN*ISO*9455- 3 94 3404589 0089386 TL3 = EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN IS0 9455-3 September 1994 UM: 621.791.35.048 : 543.24125 : 543.852.1 Descriptors: soldering, soldering fluxes, chemical analysis, determination, acid number, volumetri
12、c analysis English version Soft soldering fluxes - est methods - Part 3: Determination of acid value, potentiometric and visual titration methods (IS0 9455-3 1992) Flux de brasage tendre - Mthodes dessai - Prverfahren - Part 3: Dtermination de lindice dacide par des mthodes de titrage potentiomtriqu
13、e et visuel Titrationsmethoden Flugmittel zum Weichlten - Teil 3: Bestimmung des Surewertes, potentiometrische und visuelle (IS0 9455-3 1992) (IS0 9455-3 : 1992) This European Standard was approved by CEN on 1994-09-06. CEN members are bound to comply with the CENKENELEC Internal Regulations which s
14、tipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standar
15、d exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standar
16、ds bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Centra
17、l Secretariat: rue de Stassart 36, B-1050 Brussels O 1994 Copyright reserved to CEN members Ref. No. EN IS0 9455-3 : 1994 E CEN EN*IS0*9455- 3 94 W 3404589 0089387 95T W Page 2 EN IS0 94553 : 1994 Foreword This European Standard was taken over by the Technical Committee CEN/X 121, Welding, from the
18、work of ISOlTC 44, Soft soldering fluxes - %st methods, of the International Sta-dards Organization (ISO) *). CEN/TC 121 had decided to submit the final draft for Unique Acceptance Procedure. The result was positive. This European Standard shall be given the status of a national standard, either by
19、publication of an identical text or by endorsement, at the latest by March 1995, and conflicting national standards shall be withdrawn at the latest by March 1995. According to the CENXENELEC Internal Regulations, the following countries are bound to implement this European Standard: Austria, Belgiu
20、m, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, United Kingdom. *)See national foreword for details of textual error. Page 3 EN IS0 94553 : 1994 Soft soldering fluxes - Test methods - Part 3: Determination
21、of acid value, potentiometric and visual titration met hods 1 Scope This part of IS0 9455 specifies two methods for the determination of the acid value of a flux of types 1 and 2 only, as defined in IS0 9454-1. Method A is a potentiometric titration method and is to be considered as the reference me
22、thod. Method B is an alternative, visual end-point. titration rn et hod. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this pai? of IS0 9455. At the time of publication. the editions indicated were valid. All standai
23、ds are subject to revision, and parties to agreements based on this part of IS0 9455 are encouraged to investi- gate the possibility of applying the most recent edi- tions of the standards indicated below. Members o IEC and IS0 maintain registers of currently valid International Standards. IS0 9454-
24、1 : 1990, Soff soldering fluxes - Classifica- tion and requirements - Part I: Classification, labelling and packaging. IS0 9455-1:1990, Soft soldering fluxes - Test meth- ods - Part i: Determination of non-volatile matter, gravimetric met hod. IS0 9455-2:-1, Soft soldering fluxes - Test methods - Pa
25、rt 2: Determination of non-volatile matter, ebulliomctric method. 3 Method A: Potentiometric titration method 3.1 Principle A prepared, weighed sample of the flux is dissolved in a suitable solvent. The resulting solution is titrated with standard tetrabutyl ammonium hy- droxide solution, using a gl
26、ass electrode, the pH or mV readings being recorded simultaneously. From the graph of volume of titrant against pH or mV readings, the point of inflexion is determined, from which the acid value is calculated. NOTE 1 As fluxes of classes 1.1.3 and 1.2.3 (see IS0 9454-1) may lose some acidity during
27、the determi- nation of non-volatile matter, the non-volatile matter ob- tained from carrying out the procedure of IS0 9455-1 or IC0 9455-2 on these classes o flux should not be used for this determination. 3.2 Reagents Use only reagents of recognized analytical quality and only distilled, or deioniz
28、ed, water. 3.2.1 Tetrabutyl ammonium hydroxide (CH,CH,CH,CH,),N(OH) 0,l M (0,l mol/l). Use a commercially available standard solution or one prepared from a commercially available con- centrated standard solution by dilution with propan-2-01 (3.2.2). Alternatively, prepare an 0,l mol/l tetrabutyl am
29、monium hydroxide solution by diluting commercial concentrated solution with propan-2-01 and standardize this solution against an accurately weighed amount of benzoic acid (about 1) To be published. CEN EN*ISO*9455- 3 94 3404589 0089389 722 page 4 EN IS0 94553 : 1994 0,5 g) dissolved in dimethylforma
30、mide. previously neutralised to thymol blue. 3.2.2 Propan-2-01 (CH,),CHOH, neutralized with tetrabutyl ammonium hydroxide solution (3.2.1) to a faint pink colour, using phenolphthalein as indicator. 3.2.3 Ethanol (C,H,OH), anhydrous, neutralized with tetrabutyl ammonium hydroxide solution (3.2.1) to
31、 a faint pink colour using phenolphthalein as indi- cator. 3.2.4 Toluene (CeH,CH,), neutralized with tetrabutyl ammonium hydroxide solution (3.2.1) to a faint pink colour using phenolphthalein as indicator. 3.2.5 Ethanolltoluene mixture. Mix equal volume of the anhydrous ethanol (3.2.3) and toluene
32、(3.2.4). 3.3 Apparatus Usual laboratory apparatus and, in particular, the following. 3.3.1 Mllllvoltmeter or pH meter. 3.3.2 Glass electrode. 3.3.3 Saturated calomel, or silver chlorldelsllver, electrode. 3.3.4 Magnetic, or mechanical, stirrer, with variable speed drive. 3.4 Procedure By preliminary
33、 experiments, determine whether the sample is soluble in propan-2-01. anhydrous ethanol, toluene or the ethanolAoluene mixture. If it is not completely soluble in any of these solvents, select the one in which it appears to be the most soluble. If it is equally soluble in all four solvents then use
34、propan-2-01. Carry out the following procedure, in triplicate, on the flux sample. Weigh, to the nearest 0,001 g. approximately 0,5 g of the solid flux sample, or 2,O g of the liquid flux sample taking steps to prevent loss of volatile mat- ter during the weighing. Transfer the weighed sam- ple to a
35、 250 ml low form beaker. Add 100 ml propan-2-01 (3.2.2) or the selected sol- vent (3.2.3 to 3.2.5), according to the solubility characteristics of the flux. Cover with a watch glass and dissolve the flux by gentle agitation. Place the beaker on the stand of the titration as- sembly with the electrod
36、es, stirrer and burette in position, Adjust the speed of the stirrer to give vig- orous stirring without splashing. Titrate with the tetrabutyl ammonium hydroxide solution (3.2.1) add- ing 1 ml portions and recording the pH, or mV meter readings after each addition. As the end-point is approached, r
37、educe the additions of titrant to 0,l ml and continue titrating past the end-point. Plot the pH, or potential values against the volume of titrant added to obtain the titration curve. The point of inflexion of the curve corresponds to the end-point of the titration. NOTE 2 veniently be determined by
38、 using the derivative curve. The point of inflexion of the curve may con- Carry out a blank determination, using all reagents, for comparison purposes. 3.5 Calculation of results The acid value is expressed in milligrams of pot- assium hydroxide per gram of non-volatile matter, regardless of the alk
39、ali used to perform the titration. The acid value (expressed in milligrams of potass- ium hydroxide per gram of non-volatile matter) is given by 5611 VM mS where I is the volume, in millilitres, of tetrabutyl ammonium hydroxide solution used, mi- nus the volume needed to titrate the blank; Ai is the
40、 molarity of the tetrabutyl am- monium hydroxide solution (3.2.1); m is the mass, in grams, of the sample taken; S is the percentage non-volatile matter content of the sample, determined as described in IS0 9455-1 or IS0 9455-2 (for solid flux samples, S = 100). The acid value of the flux under test
41、 is calculated as the mean of the results obtained on each of the three test samples. CEN EN*ISO*9455- 3 94 3404589 0089390 444 4 Method 6: Titration method with visual end-point 4.1 Principle A prepared, weighed sample of the flux is dissolved in propan-2-01, ethanol, toluene, or an ethanol/toluene
42、 mixture. The solution is then titrated with standard potassium hydroxide solution and the acid value is calculated. NOTE 3 As fluxes of classes 1.1.3 and 1.2.3 (see IS0 9454-1) may lose some acidity during the determi- nation of non-volatile matter, the non-volatile matter ob- tained from carrying
43、out the procedure of IS0 9455-1 or IS0 9455-2 on these classes of flux should not be used for this determination. 4.2 Reagents Use only reagents of recognized analytical quality and only distilled, or deionized, water. 4.2.1 Ethanol, anhydrous, neutralized with potass- ium hydroxide, 0,l mol/l in al
44、cohol (4.2.5), to a faint pink colour using phenolphthalein as indicator. 4.2.2 Toluene, neutralized with potassium hy- droxide, 0,l mol/l in alcohol (4.2.5), to a faint pink colour using phenolphthalein as indicator. 4.2.3 Ethanolltoluene mixture. Mix equal volumes of the anhydrous ethanol (4.2.1).
45、 and toluene (4.2.2). 4.2.4 Propan-2-01, neutralized with potassium hy- droxide, 0,l mol/l in alcohol (4.2.5), to a faint pink colour using phenolphthalein as indicator. 4.2.5 Potassium hydroxide solution, 0,l mol/l in al- cohol. Use a commercially available standard solution or one prepared from a
46、commercially available con- centrated standard solution by dilution with ethanol (4.2.1). Alternatively, prepare a 0,l mol/l potassium hydroxide solution by dissolving 3 g hi is the molarity of the potassium hy- droxide solution (4.2.5); rn is the mass, in grams, of the sample taken; S is the percen
47、tage non-volatile matter content of the sample, determined as described in IS0 9455-1 or IS0 9455-2 (for solid nux samples, S = 100). The acid value of the flux under test is calculated as the mean of the results obtained on each of the three test samples. CEN EN*ISO*9455- 3 94 m 3404589 0089393 380
48、 m Page 6 EN IS0 9465-3 : 1994 5 Preeislon 5.1 Method A Method A of this pari of IS0 9455 was subjected to an interlaboratory test programme involving eight laboratories. For five rosin-based fluxes having acid values covering the range 170 mg to 230 mg KOH per gram of non-volatile matter, the estim
49、ates for precision data were as follows (expressed in milli- grams of potassium hydroxide per gram): Standard deviations: s, .i ,o - within laboratory 3,6 - between laboratories Repeatability r 3,Q Reproducibility R 10,o 5.2 Method B Method B of this part of IS0 9455 was subjected to a limited interlaboratory test programme, involving only five laboratories. For nine rosin-based fluxes having acid values covering the range 160 mg to 300 mg KOH per gram of non-volatile matter, the estimates for precision data were as follows (ex- pressed in milligrams of potass
