1、AECMA PREN*309b 95 1012311 0010125 464 Edition approved for publication Comments should be sent within six months after the date of publication to AECMA STANDARD NORME AECMA AECMA NORM C 7 Chairman prEN 3096 Edition P 1 December 1995 PUBLISHED BY THE EUROPEAN ASSOCIATION OF AEROSPACE INDUSTRIES (AEC
2、MA) Gulledelle 94 - B-1200 BRUXELLES - Tel. (32) 2 775 81 10 - Fax. (32) 2 775 81 11 ICs : Descriptors : ENGLISH VERSION Aerospace series Sealants Test method Determination of tack-free time Srie arospatiale Produits dtanchit Mthode dessai Dtermination du temps de perte de collant Luft- und Raumfahr
3、t Dichtmassen Prfverf ahren Bestimmung der klebfreien Zeit 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 needs of AECMA-Members. It has been technically approved by th
4、e 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, physically or functionally, without re-identification of the stand
5、ard. 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 Standardization) for formal vote. 1995-12-29 AECMA Gulledelle 94 B-1
6、200 BRUXELLES M. Wright AECMA PREN*309b 95 W 1012311 OOLO12b 310 Page 2 prEN 3096 : 1995 Blank page - AECMA PRENm3096 95 1012311 0010127 257 U Page 3 prEN 3096 : 1995 1 Scope This standard specifies a method for the determination of the tack-free time of sealants. 2 Normative reference EN 2090 Aeros
7、pace series - Aluminium alloy 2024-T3 - Clad sheet and strip - 0,4 mm I a I 6 mm 1) 3 Definition For the purpose of this standard the following definition apply : Tack-free time is the time interval, at a specified temperature and humidity, between the mixing of the base material with the curing sys
8、tem and the point where the sealant shows no signs of tackiness, when a polyethylene film is pressed against it. 4 Principle of the test method A film of polyethylene is pressed against the sealant at the end of the stated tack-free time. If no traces of sealant adhere to the film, the sealant is co
9、nsidered as tack-free. 5 Products necessary for the testing 5.1 in size. Test panel from some inert material e.g. aluminium alloy EN 2090, 1 mm x 70 mm x 150 mm 5.2 (0,l O f 0,051 mm. Strips of untreated polyethylene film, width 25 mm, length minimum 150 mm, thickness 5.3 shall be treated with a rel
10、ease agent. Optional : frame of aluminium, 70 mm x 150 mm, thickness (3,O f 0,4) mm. The frame I x + I I 70 6 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. 1) Published as AECMA standard at the date of pu
11、blication of this standard Page 4 prEN 3096 : 1995 7 Procedure A clean test panel (see 5.1) shall be covered with freshly mixed sealing compound to a thickness of (3,O f 0,4) mm. NOTE : The right thickness is easier obtained by means of a frame (see 5.3). The test panel shall be kept at (23 * 2) OC
12、and (50 * 5) % relative humidity throughout the test. At the end of the specified tack-free time, two polyethylene strips (see 5.2) shall be applied to the whole length of the sealant compound and held in contact with the sealant surface for 2 min. The strips shall then be slowly and evenly peeled o
13、ff by hand at right angles to the sealant surface. The sealant is considered tack-free if the polyethylene strips come away clean and free of sealant. 8 Expression of results If no sealant adheres to the polyethylene strips the result shall be given as passing, otherwise failing the test. 9 Designat
14、ion EXAMPLE : EN3096 Number of this standard 10 Test report The test report shall include the following information : - - - - - - test results ; - date of testing. identification of the sample, batch number ; number of this standard ; curing conditions, temperature and humidity ; number of test specimens ; the material of the test panel ;
