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1、INTERNATIONAL STANDARD ISO 16862 First edition 2003-11-15 Reference number ISO 16862:2003(E) ISO 2003 Paints and varnishes Evaluation of sag resistance Peintures et vernis valuation de la rsistance la formation de festons Copyright International Organization for Standardization Provided by IHS under
2、 license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 16862:2003(E) ii ISO 2003 All rights reserved PDF disclaimer This PDF file may contain embedded typefaces. In accordance
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5、very care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2003 All rights reserved. Unless otherwise specified, no part of this publica
6、tion may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva
7、20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo re
8、production or networking permitted without license from IHS -,-,- ISO 16862:2003(E) ISO 2003 All rights reserved iii Contents Page 1Scope 1 2Normative references 1 3Terms and definitions 2 4Apparatus . 2 5Sampling . 2 6Test panels . 2 7Procedure . 2 8Expression of results 5 9Precision . 6 10Test rep
9、ort 6 Annex A (normative) Sag index applicator blades 7 Bibliography . 9 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted witho
10、ut license from IHS -,-,- ISO 16862:2003(E) iv ISO 2003 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO
11、technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates clo
12、sely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Dra
13、ft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this docu
14、ment may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 16862 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9, General test methods for paints and varnishes. Copyright International Organiza
15、tion for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 16862:2003(E) ISO 2003 All rights reserved v Introduction When a wet coat o
16、f paint is applied to an inclined surface, the coat will flow down the surface under its own weight with cohesive forces opposing this flow. The balance of rheological and gravitational forces will allow a certain wet-film thickness to be applied without this unwanted flow becoming objectionable. Fl
17、ow down an inclined surface is normally unstable, particularly if the coat is of uneven thickness, and it is this instability that leads to unsightly sags and tears. For a vertical surface, the gravitational force per unit area of surface, i.e. the stress, is given by , where is the film thickness i
18、n micrometres, is the density of the coat of paint in kilograms per cubic metre and is the gravitational constant in metres per second squared. The cohesive force per unit area of the surface is given by , where is the Newtonian viscosity in pascal seconds and is the shear rate in reciprocal seconds
19、. This International Standard describes two methods for determining the maximum wet-film thickness of a coating which can be applied to a vertical surface without giving rise to sagging or similar phenomena. The first method is carried out on a small scale using sag index applicators and the second
20、is a larger-scale, practical test. h d ghd g V d/dlV d/dl Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from
21、 IHS -,-,- . vi Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARDISO 16862
22、:2003(E) ISO 2003 All rights reserved 1 Paints and varnishes Evaluation of sag resistance 1Scope This International Standard describes test methods for evaluating the sag resistance (resistance to sagging) of paints, varnishes and similar coating materials (coatings) when applied to a substrate and
23、held in a vertical position. Evaluation of the sag resistance can be carried out after the coating has been applied as follows: a)using a sag index applicator on a horizontally placed test panel which is afterwards put into a vertical position, or b)using a spray gun for application on a substrate i
24、n a vertical position. NOTEBrush or roller application can also be used provided that an even coating is applied. This International Standard is applicable to liquid coatings only. 2Normative references The following referenced documents are indispensable for the application of this document. For da
25、ted references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1513, Paints and varnishes Examination and preparation of samples for testing ISO 1514, Paints and varnishes Standard panels for testing ISO 1
26、517, Paints and varnishes Surface-drying test Ballotini method ISO 2808, Paints and varnishes Determination of film thickness ISO 2884-1, Paints and varnishes Determination of viscosity using rotary viscometers Part 1: Cone-and- plate viscometer operated at a high rate of shear ISO 2884-2, Paints an
27、d varnishes Determination of viscosity using rotary viscometers Part 2: Disc or ball viscometer operated at a specified speed ISO 3270, Paints and varnishes and their raw materials Temperatures and humidities for conditioning and testing ISO 15528, Paints, varnishes and raw materials for paints and
28、varnishes Sampling Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 16862:2003(E) 2 ISO 2003
29、 All rights reserved 3Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 sag resistance greatest wet-film thickness, in micrometres, of a coating, under specified conditions of application, for a specified substrate and under specified environment
30、al conditions, for which the coating will not have a tendency to flow during the drying process when placed in an inclined position NOTE 1This flow is known as sagging. NOTE 2Surface appearances typical of sagging are generally characterized by runs, tear drops, curtains or sags. 4Apparatus 4.1Sag i
31、ndex applicator, with gaps of defined clearance as given in Annex A, for applying film stripes of appropriate thickness. Examples of sag index applicators are given in Annex A. 4.2Spraying device, airless or air-assisted, for applying the coating. 4.3Wet-film thickness gauge, with an appropriate ran
32、ge. 4.4Stirrer. 5Sampling Take a representative sample of the product to be tested, as described in ISO 15528, and prepare the sample for testing, as described in ISO 1513. 6Test panels Use standard panels prepared in accordance with ISO 1514. NOTEFor the sag index applicator method, glass panels sh
33、ould preferably be used to provide a flat surface over which the applicator will lay down stripes of coating of even thickness. A sag index applicator will not run consistently over a curved substrate. 7Procedure 7.1Test conditions Unless otherwise stipulated or agreed, carry out the test under stan
34、dard conditions, i.e. a temperature of and a relative humidity of in accordance with ISO 3270. The film thickness of a coating material at which sag does not occur when applied in accordance with 7.2.3 and 7.3.3 might differ. The values obtained by these methods are dependent on shear-rate at applic
35、ation, and the temperature. Moisture-cure and water-thinnable coating materials are particularly influenced by the relative humidity. The sagging tendency of two-component coatings is additionally influenced by the period between mixing the components and application. (232) C (505)% Copyright Intern
36、ational Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 16862:2003(E) ISO 2003 All rights reserved 3 7.2Using a sag
37、 index applicator 7.2.1Principle Two test panels are coated with the material under test and the sag index applicator is drawn across the panels. The panels are placed vertically and the thickest stripe which shows no sign of sagging is noted on each panel. The actual wet-film thickness of each stri
38、pe is measured on a third panel. 7.2.2General A pre-shear programme is essential for a drawdown sag test to duplicate the breakdown in structure that occurs when thixotropic paints are applied by brush or another practical application method. The procedure therefore includes the pre-shearing of pain
39、ts just prior to application. The rate of rotation and time of stirring shall be agreed between interested parties. NOTE 1Examples of procedures for pre-shearing are given in ASTM D 4400, which is an equivalent method using an applicator blade. The wet-film thickness obtained through application is,
40、 depending on viscosity, rheology and application speed, smaller than the gap depth of the applicator. For this reason, it is necessary to determine the actual wet-film thickness applied and record this along with the largest gap size which does not produces sagging. NOTE 2If the test is being carri
41、ed out for quality control purposes as a pass/fail test, then measurement of actual wet-film thickness may not be necessary. Select a sag index applicator which will lay down a range of wet-film thicknesses which includes that specified for the product being tested. It may be necessary to determine
42、which range is most suitable by experiment. NOTE 3For example, for a thixotropic thick film material with a sag resistance of approximately of wet film, a blade with a maximum gap depth should be used. In the case of a polyurethane finishing paint with a flow time of approximately through a cup with
43、 a orifice, in accordance with ISO 2431, and a sag resistance of , a blade with a maximum depth of will suffice. Ensure that the test panels are clean and dry. If necessary, clean with a suitable solvent and wipe dry with clean tissue or lint-free cloth. 7.2.3Application Lay one test panel horizonta
44、lly and secure it over a sheet of tissue paper on a firm surface. Place the sag index applicator on one end of the horizontal test panel with the clearance gaps facing downwards. Carry out the agreed pre-shear programme (see 7.2.2) and immediately pour sufficient coating material against the applica
45、tor near the edge with the clearance gaps, avoiding bubble formation. Ensure that there is sufficient paint to enable properly formed stripes to be drawn down over a length of at least , with excess paint being carried to the end of the panel and on to the tissue underneath. Using a guide as necessa
46、ry, immediately draw the applicator through the wet paint at a constant speed and with firm downward pressure so that separate stripes of wet paint are cleanly formed. If stripes which are not straight or which do not have clearly defined edges are formed, discard the test panel and repeat the appli
47、cation on a fresh panel. NOTEExamples of methods for the automated application of paint films are described in ASTM D 823. Immediately place the test panel in a vertical position with the stripes horizontal and with the smallest film thickness at the top. Repeat the application procedure on a second
48、 panel. 60m 450m 60 s4 mm60m 150m 100 mm Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/21/2007 01:26:34 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 16862:2003(E) 4 ISO 2003 All rights reserved Using a third panel, repeat the application procedure, keeping the forc