1、 AECMA PREN*3094 95 = LO1231h O010120 9T2 Edition approved for publication Comments should be sent within six months after the date of publication to AECMA Gulledelle 94 1995-1 2-29 B-1200 BRUXELLES AECMA STANDARD NORME AECMA AECMA NORM C 7 Chairman M. Wright prEN 3094 Edition P 1 December 1995 PUBL
2、ISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AECMA) Gulledelle 94 - B-1200 BRUXELLES - Tel. (32) 2 775 81 1 O - Fax. (32) 2 775 81 11 ICs : Descriptors : ENGLISH VERSION Aerospace series Sealants Test method Determination of application time Srie arospatiale Produits dtanchit Mthode de
3、ssai Dtermination du temps dapplication Luft- und Raumfahrt Dichtmassen Prfverfahren Bestimmung der Verarbeitungszeit This “Aerospace Series Prestandard has been drawn up under the responsibility of AECMA (The European Association of Aerospace Industries). It is published on green paper for the need
4、s of AECMA-Members. It has been technically approved by the experts of the concerned Technical Committee following comment by the Member countries. Subsequent to the publication of this Prestandard, the technical content shall not be changed to an extent that interchangeability is affected, physical
5、ly or functionally, without re-identification of the standard. After examination and signature of the AECMA Standard Checking Centre (NPS) and formal agreement of the Official Services of the Member countries it will be submitted as a draft European Standard to CEN (European Committee for Standardiz
6、ation) for formal vote. aecma 1995 AECMA PREN*309Y 95 1012311 O010121 839 = Page 2 prEN 3094 : 1995 Blank page AECMA PRENx3094 95 1012311 OOLOL22 775 Page 3 prEN 3094 : 1995 1 Scope This standard specifies two methods for the determination of the application time of sealants. 2 Normative reference I
7、S0 2555 Plastics - Resins in the liquid state or as emulsions or dispersions - Determination of apparent viscosity by the Brookfield Test method 3 Definition For the purpose of this standard the following definition apply : Application time is the time interval, at a specified temperature and humidi
8、ty, between the mixing of the base material with the curing system and the point where the sealant has cured to a state where application by normal methods is no longer possible. 4 Principie of the test method The application time is determined by two different methods, depending on the viscosity of
9、 the sealant. 4.1 Method A (viscosity) For sealants with a viscosity lower than 75 Pa.s, the viscosity is measured with a BROOKFIELD viscometer or equivalent at the end of the specified application time according to IS0 2555. 4.2 Method B (extrusion) For sealants with a viscosity higher than 75 Pa.s
10、 the mass extruded through a nozzle under specified conditions is measured at the end of the stated application time. 5 Method A (viscosity) 5.1 Conditioning The base compound and the curing system shall be stabilized at (23 f 2) OC in closed containers for at least 8 h before testing. 5.2 Procedure
11、 The base compound shall be mixed with the proper amount of the curing system and filled into a can. The can shall be kept at (23 I2)OC and tightly covered until the testing of the viscosity. At the end of the specified application time, measured from the beginning of the mixing period, the viscosit
12、y of the sealant shall be determined according to IS0 2555 using spindle, rotation speed and stirring procedures as defined in the material specification. 5.3 The reading taken on the viscometer shall be converted into a viscosity value using the procedure stated for the viscometer, spindle and spee
13、d. Calculation and expression of results AECMA PRENx3094 95 1012311 0010123 bo1 = h Page 4 prEN 3094 : 1995 6 Method B (extrusion) 6.1 Apparatus 6.1 .l Sealant application gun 6.1.2 Sealant cartridge See figure 1 Dimensions in millimetres r Cartridge r L Diameter 40 f 0.1 - Nozzle Figure 1 6.1.3 Noz
14、zle See figure 2 Dimensions in millimetres Nozzle I Figure 2 AECMA PREN*3094 95 1012311 0010124 5Y Page 5 prEN 3094 : 1995 6.1.4 6.1.5 Air supply with a pressure of (620 IC 351 kPa Balance with an accuracy of 0,l g. 6.2 Conditioning The base compound and the curing system shall be stabilized at (23
15、f 2) OC in closed containers for at least 8 h before testing. 6.3 Procedure At least 250 g of the base compound shall be mixed with the proper amount of the curing system. The mixed sealant shall promptly be filled into a cartridge (see 7.1.2) with a nozzle (see 7.1.3) and placed in a gun. The gun a
16、nd sealant shall be maintained at (23 -I 2) OC throughout the test. The gun shall be attached to a constant air supply of (620 k 35) kPa. Initially 50 mm to 80 mm of sealant shall be extruded to clear trapped air. At the end of the specified application time, measured from the beginning of the mixin
17、g period, the sealant shall be extruded into a suitable receptacle for (60 f 2) s and the amount of extruded sealant determined by weighing. 6.4 Calculation and expression of results The amount of extruded sealant shall be expressed in g.min-. 7 Designation EXAMPLE : EN3094A Number of this standard
18、1 Type of method (A or B) u 8 Test report The test report shall include the following information : - identification of the sample, batch number, - number of this standard and test method (A or BI, - viscometer, spindle, rotating speed used, time for rotating (if more than 1 min) and stirring procedures, when testing according to method A, - temperature and humidity, - number of test specimens, - test results, - whether or not the results are within the limits of the material specification, - date of testing.
