1、BRITISH STANDARD BS 3712-4: 1991 Building and construction sealants Part 4: Method of test for adhesion in peelBS3712-4:1991 This British Standard, having been prepared under the directionof the Elements and Components (of Diverse Materials) for Buildings Standards Policy Committee, was published un
2、derthe authority of the Standards Board and comes into effect on 30 August1991 BSI 05-1999 First published August 1985 Second edition August 1991 The following BSI references relate to the work on this standard: Committee reference ECB/3 Special announcement in BSINews August 1991 ISBN 0 580 19922 3
3、 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Elements and Components (of Diverse Materials) for Buildings Standards Policy Committee (ECB/-) to Technical Committee ECB/3, upon which the following bodies were represented: Aluminium Wi
4、ndow Association Association of Sealant Applicators British Adhesives and Sealant Association Building Employers Confederation Department of the Environment (Building Research Establishment) Department of the Environment (Property Services Agency) Flat Glass Manufacturers Association Glass and Glazi
5、ng Federation Institution of Civil Engineers Refined Bitumen Association Ltd. Society of Architectural and Associated Technicians Society of Chemical Industry Water Services Association of England and Wales Amendments issued since publication Amd. No. Date CommentsBS 3712-4:1991 BSI 05-1999 i Conten
6、ts Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Adhesion in peel 1 Figure 1 Diagram showing arrangement of test strips for the adhesion in peel test 2 Publication(s) referred to Inside back coverBS3712-4:1991 ii BSI 05-1999 Foreword This Part of BS3712, prep
7、ared under the direction of the Elements and Components (of Diverse Materials) for Buildings Standards Policy Committee, is a new edition of and supersedes BS3712-4:1985 which is withdrawn. This new edition has been necessitated by the need to delete the methods of test for tensile properties (which
8、 have been published as BS EN28339 and BS EN28340), elastic recovery (which has been published as BS EN27389), and loss of mass after heat ageing (the subject of which is being developed in ISO/TC59/SC8 as a draft international standard ISO/DIS10563). No review of or technical amendment to the remai
9、ning method of test in this Part of BS3712 has been made except that in3.4.1.6 and3.4.2.8 two alternative British Standard references are given. The adhesion in peel test is based on the existing tests in BS4254, BS5215 and BS5889, which differ slightly from each other owing to the different cure ch
10、aracteristics of the three types of sealant. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligatio
11、ns. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside
12、 front cover.BS3712-4:1991 BSI 05-1999 1 1 Scope This Part of BS3712 gives a test method for the following properties of building and construction sealants: a) adhesion in peel for fresh sealant on specific surfaces; b) adhesion in peel for fresh sealant on matured sealant. NOTEThe titles of the pub
13、lications referred to in this standard are listed on the inside back cover. 2 Definitions The definitions given in BS3712-1,BS3712-2 andBS3712-3 apply. 3 Adhesion in peel 3.1 Apparatus and accessory materials 3.1.1 Testing machine, with tension grips capable of pulling at a rate of separation of50 5
14、mm/min with a dial or chart calibrated to record the force. 3.1.2 Paper masking tape, 25mm wide. 3.1.3 Spacer bars, at least125mm long 1.5mm wide. The bars shall be1.5mm thick for testing fresh sealant on specific surfaces or6mm thick for testing fresh sealant on matured sealant. 3.1.4 Thin flexible
15、 backing material, 225mm 75mm to which the compound will adhere throughout the test and which requires a force appreciably less than25N to be pulled back at an angle of180 (e.g.cloth, brass screen, unsized cotton duck fabric, open weave glass cloth). 3.1.5 12mm diameter rod, steel or glass,150mm lon
16、g. 3.1.6 Ventilated ovens, capable of being maintained at a temperature in the range of23 C to50 2 C and a relative humidity in the range65 5% r.h. to95 5% r.h. 3.1.7 300 W sunlamp. 3.1.8 Power stirrer or spatula, for mixing multipart sealants. 3.2 Test surfaces One or more of the following test sur
17、faces shall be used. a) Two pieces of untreated aluminium alloy approximately125mm 75mm not less than3mm thick of grade6082 T6 as specified in BS1470 or grade6063 T6 or6082 T6 as specified in BS1474. b) Two blocks of cement mortar approximately125mm 75mm 25mm prepared as follows. 1) Mix one part by
18、dry mass of ordinary Portland cement complying with BS 12 with1; parts by dry mass of sand complying with BS4550-6 and add water to give a water cement ratio of0.35 to0.40. The grading of the sand shall be such that100% by mass shall pass through a850m sieve complying with BS410 and0% to10% by mass
19、shall pass through a600 m sieve complying with BS410. Ensure that the sand is thoroughly washed and dried before use. 2) Transfer the mortar immediately to rigid plastics moulds in about four layers, each being thoroughly compacted on a suitable vibrating table. 3) Cure the blocks in the moulds for2
20、4h in an atmosphere of not less than90% r.h. 4) Remove blocks from the moulds and cure for a further28 days in water at room temperature, using a volume of water not less than400mL per block. 5) Dry the blocks at a temperature of110 C for at least12h and store in a ventilated oven (see3.1.6) for at
21、least28 days at23 2 C and65 5% r.h. If blocks are not required for immediate use and are subsequently stored under alternative or uncontrolled conditions, store them for at least a further7 days at23 2 C and65 5% r.h. before use. c) Two pieces of clear float glass,125mm 75mm, not less than6mm thick.
22、 d) Two pieces of any other material125mm 75mm and of sufficient thickness to withstand distortion during the test. 3.3 Cleaning of test surfaces Before constructing the test assemblies, clean the test surfaces as follows. a) Clear float glass and aluminium. Remove major contamination by cleaning wi
23、th water, detergent solution or solvents. Clean the surface with butanone (ethyl methyl ketone) or similar solvent. Wash with dilute detergent solution and rinse with distilled or deionized water. Rinse in industrial methylated spirits and air dry.BS3712-4:1991 2 BSI 05-1999 b) Mortar. Remove loose
24、dust by brushing, using a clean stiff bristle brush. If it is found, after the preparation of the block, that the surface has any cavity greater than2mm diameter, reject the block. c) Other material. Proceed as directed by the manufacturer of the material. 3.4 Preparation of test assemblies NOTEThe
25、procedures described in the clause require special expertise. They should, therefore, be carried out in laboratories having considerable experience in this field. 3.4.1 Fresh sealant on specific surface 3.4.1.1 Prepare not less than two test assemblies for each test surface as described in3.4.1.2 to
26、3.4.1.8. 3.4.1.2 Place a strip of25mm paper masking tape(3.1.2) across the width of a clean test surface along and parallel to the lower edge, leaving an area of100mm 75mm exposed (see Figure 1). Where appropriate, prime the surface to which the sealant is intended to adhere. Figure 1 Diagram showin
27、g arrangement of test strips for the adhesion in peel testBS3712-4:1991 BSI 05-1999 3 3.4.1.3 Condition an appropriate quantity of the sealant at23 2 C in a closed container or an unopened cartridge for a period of at least16h. Then mix appropriate amounts of the conditioned components of multipart
28、sealants, either by hand for10min, using a spatula, or by using a power stirrer(3.1.8) until uniform mixing is achieved, the speed of rotation being such that the minimum amount of air is entrained in the mixed sealant. 3.4.1.4 Spread a portion of the sealant to a minimum thickness of2mm over the wh
29、ole area of the test surface, including the tape (i.e.125mm 75mm). 3.4.1.5 Insert the spacer bars(3.1.3) on the long edge of the test surface (see Figure 1). Then smear the backing material with the mixed sealant at one end over an area of125mm 75mm and force the sealant into the backing material us
30、ing a spatula. Lay the impregnated material over the sealant on the test surface, taking care that the minimum amount of air is entrapped. Roll the backing material with the rod to obtain a thickness of sealant of1.5mm between the backing material and the test surface. 3.4.1.6 Cure the assembly for7
31、n days, where n is a specified whole number, at23 2 C and50 5% r.h. or65 5% r.h. in a ventilated oven, or as required in BS5215 or BS5889. NOTETo aid adhesion of the backing material, the test assembly may be coated with a1mm layer of the same sealant within a period of3 days, thereafter returning t
32、he assembly to the enclosure and resuming the curing cycle. 3.4.1.7 After curing, subject sealant assemblies made from transparent glazing materials to the following procedure. Continuously expose the transparent side of the assemblies to the radiation from a sunlamp(3.1.7) for96h at a distance of30
33、0mm from the surface of the lamp and normal to the axis of the lamp. Before placing the assemblies under the lamp, switch on for15min. Then check the ultraviolet output of the lamp using a meter 1)operating in the range300nm to400nm. The ultraviolet intensity shall be not less than25W/m 2at a distan
34、ce of300mm from the outside of the lamp glass on the centreline of the lamp. Provide ventilation so that the temperature of the glass surface of each assembly does not exceed50C. Do not test more than two assemblies at the same time under one lamp. 3.4.1.8 For all assemblies, cut through the backing
35、 material and sealant to the test surface along its whole length with a sharp knife or razor blade, leaving two strips of sealant and backing material25mm wide separated by a space approximately10mm wide (see Figure 1). Immerse the assembly in distilled or deionized water at23 2 C for7 days. 3.4.2 F
36、resh sealant on matured sealant NOTEThe object of this test is to assess the adhesion between freshly applied sealant and matured sealant. This property is of particular relevance for sealant application started on one day and completed on the next and for multiple application of sealants, especiall
37、y curable sealants. The test may, with caution, be modified to assess the adhesion between two dissimilar materials used in the same joint but attention is drawn to the need to determine the compatibility of the materials. The conditions of exposure may be changed by agreement. 3.4.2.1 Prepare not l
38、ess than two test assemblies for each test surface as described in3.4.2.2 to3.4.2.9. 3.4.2.2 Place a strip of25mm paper masking tape(3.1.2) across the width of a clean test surface along and parallel to the lower edge, leaving an area of100mm 75mm exposed (see Figure 1). Where appropriate, prime the
39、 surface to which the sealant is intended to adhere. 3.4.2.3 Condition an appropriate quantity of the sealant at23 2 C in a closed container or an unopened cartridge for a period of at least16h. Then mix appropriate amounts of the conditioned components of multipart sealants, either by hand for10min
40、, using a spatula, or by using a power stirrer(3.1.8) until uniform mixing is achieved, the speed of rotation being such that the minimum amount of air is entrained in the mixed sealant. 3.4.2.4 Spread a portion of the sealant to a minimum thickness of2mm over the whole area of the test surface incl
41、uding the tape (i.e.125mm 75mm). 3.4.2.5 Expose the sealant on the plate in a ventilated oven(3.1.6) for7 days at23 2 C and80 5% r.h. and for a further7 days at50 1 C and80 5% r.h. 3.4.2.6 Remove the assembly from the oven and allow to cool. Clean the surface of the matured sealant as specified by t
42、he manufacturer. Then cover the matured sealant with fresh sealant prepared as described in3.4.2.3 to give a total sealant thickness of6mm. 1) A U.P.V. J.221 long wave UV meter is known to be suitable.BS3712-4:1991 4 BSI 05-1999 3.4.2.7 Insert the spacer bars(3.1.3) on the long edge of the test surf
43、ace (see Figure 1). Then smear the backing material with the mixed sealant at one end over an area of125mm 75mm and force the sealant into the backing material using a spatula. Lay the impregnated material over the sealant on the test surface, taking care that the minimum amount of air is entrapped.
44、 Roll the backing material with the rod to obtain a thickness of sealant of6mm, using appropriate size spacer bars(3.1.3), between the backing material and the test surface. 3.4.2.8 Cure the assembly for7n days, where n is a specified whole number, at23 2 C and50 5% r.h. or65 6% r.h. in a ventilated
45、 oven, or as required in BS5215 or BS5889. NOTETo aid adhesion of the backing material, the test assembly may be coated with a1mm layer of the same sealant within a period of3 days, thereafter returning the assembly to the enclosure and resuming the curing cycle. 3.4.2.9 Cut through the backing mate
46、rial and sealant to the test surface along its whole length with a sharp knife or razor blade, leaving two strips of sealant and backing material25mm wide separated by a space approximately10mm wide (see Figure 1). Immerse the assembly in distilled or deionized water at23 2 C for7 days. 3.5 Procedur
47、e 3.5.1 Immediately after removing each assembly from the water, wipe it dry and release the portion of the backing material covering the masking tape. Fold back the two strips of backing material at an angle of180 and place the assembly in the testing machine(3.1.1). 3.5.2 Pull one strip of backing
48、 material at a rate of separation of50mm/min for1min. After a reasonably steady value has been obtained on the testing machine, record the peel strength in newtons shown on the dial or recording chart. Measure the area over which the sealant has failed in adhesion to the test surface. For fresh seal
49、ant applied to mature sealant, note where failure occurs. If the backing material peels from the sealant during the test, disregard the result and repeat the test. 3.5.3 Repeat the procedure described in3.5.2 for the other strip of backing material. 3.6 Test report The test report shall contain the following information: a) the number of this British Standard, i.e.BS3712-4; b) the name and type of sealant; c) the batch of sealant from which test samples were taken (if known) and expiry date; d) the
