1、BRITISH STANDARD BS 5131-1.8: 1981 Methods of test for Footwear and footwear materials Part1: Adhesives Section1.8 Rate of bond strength development in shear of hot melt adhesives for lasting NOTEIt is recommended that this Section should be read in conjunction with the information in the General in
2、troduction to BS5131, published separately. UDC 685.31:620.1:665.9:539.415.2BS5131-1.8:1981 This British Standard, having been prepared under the directionof the Clothing Standards Committee, was published under the authority ofthe Executive Board and comesinto effect on 31August1981 BSI 11-1999 The
3、 following BSI references relate to the work on this standard: Committee reference CLT/7 Draft for comment80/35410 DC ISBN 0 580 12206 9 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
4、. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to5 and a back cover. This standard has been updated (see copyright date) and may have had amendments in
5、corporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date of issue CommentsBS5131-1.8:1981 BSI 11-1999 i Contents Page 1 Scope 1 2 References 1 3 Principle 1 4 Preparation of adherends 1 5 Apparatus 2 6 Procedure 2 7 Expres
6、sion of results 4 8 Test report 4 Figure 1 Insole test piece 1 Figure 2 Test device 3 Figure 3 Upper clamp 4 Figure 4 Stages in the formation and tensioning of a bond 5ii blankBS5131-1.8:1981 BSI 11-1999 1 1 Scope This Section describes the preparation of shear test joints with hot melt adhesives by
7、 a method which simulates the bonding of the shoe upper to the insole in the lasting operation. The method determines, for a chosen application temperature, the resistance to shear of the joint after various wiper plate dwell times. This enables the setting characteristics of adhesives to be compare
8、d in terms of the rate of bond strength development and/or wiper plate dwell time. The method is applicable to combinations of materials where at least one of the adherends is flexible (normally shoe insole and upper materials) and to hot melt adhesives in free forms, e.g.granules or rods. The absol
9、ute performance of an adhesive in a lasting machine can only be determined in factory trials. 2 References This Section refers to the following standards publications: BS5131, Methods of test for footwear and footwear materials Subsection1.1.3 Preparation of test assemblies for adhesion tests. BS535
10、0, Methods of test for adhesives PartC5Determination of bond strength in longitudinal shear. 3 Principle A rectangular test piece of insole material is clamped horizontally in a test device, having a wiper plate (optionally heated to simulate a production lasting machine) to fold a test piece of upp
11、er material on to hot melt adhesive applied to the insole material and so to form a bond. After a chosen dwell time has elapsed, the joint is stressed by tensioning the upper material with a preset force. Whether the joint fails or remains bonded is recorded for each combination of application tempe
12、rature, wiper plate temperature, dwell time and force. 4 Preparation of adherends 4.1 Conditioning. Before preparation, keep all adherend materials for at least24h in an atmosphere at20 2 C and65 2% relative humidity. Keep them under these conditions between preparation and adhesive application. 4.2
13、 Number and size of test pieces. For each test condition cut: a) from insole material at least four test pieces, each30 0.5mm by approximately50mm b) from upper material at least four test pieces, each30 0.5mm width and of sufficient length when folded, to extend beyond the bonding area of insole by
14、 about5mm. Cut all test pieces from an adherend material in the same direction. If possible directional effects are being investigated, cut sets of test pieces in the various directions. It is useful to cut several additional test pieces at this stage as some of the bonded assemblies may have to be
15、rejected (see6.3). The bond in lasting is normally between the reverse or flesh surface of an upper material and the reverse (non-wearing) surface of a leather or board insole material. These surfaces are not normally prepared before application of the adhesive. If any preparation is necessary, foll
16、ow the procedures described in4.2.1 to4.2.7 of BS5131-1.1.3:1976. If mechanical preparation of an adherend is necessary, this may be difficult to carry out on small test pieces. In this case larger rectangles may be cut and prepared then cut into individual test pieces. 4.3 Application of paper or t
17、ape. Apply a strip of self-adhesive release paper, at least15mm wide, across the bonding surface of each insole material test piece to define a bonding margin30mm 10mm at one end of the test piece (see Figure 1). Figure 1 Insole test pieceBS5131-1.8:1981 2 BSI 11-1999 5 Apparatus 5.1 Test device, as
18、 shown in Figure 2, equipped with clamps to secure the insole material to a horizontal block and the upper material vertically at the edge of the insole (see Figure 3). After application of adhesive Figure 4(a) a wiper plate, which moves horizontally, folds the upper material over at least10mm lengt
19、h of the insole Figure 4(b). The wiper plate may be fitted with a thermo-statically controlled heating element. The position of the wiper plate in the vertical plane is adjustable by a lockable screw mechanism. The clamp holding the upper material may itself be held in the device. The lower end of t
20、his clamp is linked to a spring balance, normally of maximum capacity100N. The balance is preset to a chosen force by vertical adjustment of the balance body to tension the spring, e.g.by mounting the balance in a sliding clamp while the upper material clamp is held fixed. Withdrawal of the wiper pl
21、ate Figure 4(c) releases the upper material clamp so that the upper material is immediately tensioned by the balance, exerting a shear force on the bond line. 5.2 Adhesive applicator. An applicator gun 1)or other apparatus equipped with a melting chamber and an application nozzle, complying with the
22、 following requirements. a) The melt chamber shall accept adhesive in granular form. The chamber shall be sufficiently small such that less than100g of adhesive is sufficient to purge the apparatus. b) The melt chamber and nozzle shall be electrically heated, and capable of melting the adhesive and
23、heating it to the desired application temperature. This is normally in the range100 C to300 C. The adhesive temperature at the nozzle shall be maintained within 5 C of the chosen or recommended application temperature. c) A pneumatic or mechanical system shall enable molten adhesive to be expelled a
24、t a steady rate. The quantity applied in one pass shall be sufficient to ensure that a slight excess exudes from the edges of the test assembly on pressing. NOTE 1Apparatus working at a fixed temperature is generally unsuitable, but may be used for testing adhesives applied at this temperature. NOTE
25、 2Apparatus requiring the adhesive to be in precise forms, e.g.sticks or a continuous rod of fixed dimensions, is generally unsuitable, but may be used for testing adhesives available in these particular forms. 5.3 Thermocouple pyrometer, suitable for checking the temperature of the applied adhesive
26、 and the surface temperature of the wiper plate. 6 Procedure 6.1 Preparation of adhesive and applicator. Heat the applicator to a temperature that is suitable for purging out the remains of the previous sample of adhesive. This may need to be higher than the normal application temperature of the adh
27、esive that is to be tested, especially if the previous sample had a higher application temperature. If the adhesive is in block, stick or rod form, break or cut it into suitable small pieces. Place a quantity in the melt chamber and allow it to melt. Purge the applicator by expelling adhesive from t
28、he nozzle on to waste paper or release paper, until the adhesive ribbon is of uniform colour and apparently free from contamination by previous samples and charred particles. If necessary, purge with further quantities of adhesive until this condition is achieved. Expel the remainder of the adhesive
29、 charge and check that the melt chamber contains no residues. Lower the applicator temperature, if necessary, to the chosen or recommended application temperature of the adhesive. Recharge the melt chamber with fresh adhesive and allow this to reach the application temperature. Check the temperature
30、 of a sample of adhesive as it is being expelled from the nozzle, using the pyrometer described in5.3. The adhesive manufacturers recommendations concerning the hot storage life of the adhesive should be noted. If not specified, the time between the start of melting and the completion of bonding sha
31、ll be as short as possible but shall not exceed30min. NOTEAdhesives in rod form, intended for melting immediately before application, may have particularly short hot storage lives. 6.2 Clamping of test pieces. Clamp the insole test piece (bonding surface uppermost) so that the end to be bonded is al
32、igned with the front end of the horizontal block. Insert the upper material (bondingsurface towards the insole) in its clamp and secure the clamp in the device. Adjust the vertical setting of the wiper plate so that it just clears the adherends when the upper is folded over the insole, and lock this
33、 setting. If a heated wiper plate is to be used, heat to the chosen temperature and check this with a surface pyrometer. Attach the spring balance to the upper material clamp and adjust to the desired tension. 1) A suitable laboratory applicator for most adhesives is the MP-300 assembly gun availabl
34、e with a control unit from Dynamelt UK Limited, Unit15, Middle March, Long March Industrial Estate, Daventry, Northants.BS5131-1.8:1981 BSI 11-1999 3 6.3 Bonding and testing. Apply an adequate ribbon of adhesive, (see note1), with one pass of the nozzle, over the area of insole material not covered
35、by release paper. Immediately operate the wiper plate to fold over the upper material. The time from the commencement of adhesive application to the completion of the wiping action shall not exceed3s. NOTE 1The quantity of adhesive applied should be sufficient to ensure that a small excess exudes fr
36、om the joint beyond the bonding margin, forming a fillet on setting see Figure 4(c). The chosen dwell time will normally be between1s and10s from completion of wiping. Once this time has elapsed, withdraw the wiper plate which will cause the upper material clamp to be released and place the joint un
37、der tension. Note whether the joint immediately fails or remains bonded. If the joint fails, check the bonding area for completeness of adhesive coverage. If more than5% of the area is not covered, reject this result. Examine the separated joint and note the type(s) of failure and the proportion of
38、total bonded area over which each type of bond failure has occured. NOTE 2Types of bond failure may be classified as follows: a) cohesive failure of adhesive; b) failure of adhesion to either adherend material; c) failure of adherend material, surface layer; d) failure of adherend material, below su
39、rface. Repeat the procedure to obtain four valid results for the chosen test condition. Figure 2 Test deviceBS5131-1.8:1981 4 BSI 11-1999 Testing may be continued with further test pieces using other test conditions. One or more of the following procedures may be adopted. 1) Use a fixed dwell time a
40、nd vary the tensile force applied to the upper material. This will enable the shear resistance of the joint to be determined for the chosen bonding conditions. Joints that do not fail may be removed from the device and subsequently tested in a tensile testing machine to determine the shear resistanc
41、e. NOTE 3An appropriate test method is described in5.5 of BS5350-C5:1976. 2) Use a fixed tensile force and vary the dwell time. This will enable the minimum dwell (setting) time necessary for the joint to sustain the chosen tensile force to be determined. Testing according to procedures1) or2) may b
42、e carried out at more than one suitable adhesive application temperature. If the wiper plate is heated to simulate heated wiper plates in a lasting machine, procedures1) or2) may be carried out at one or more wiper plate temperatures. 7 Expression of results Record for each test the dwell time in se
43、conds, the force in newtons applied to the joint and whether the joint passed (i.e.remained bonded) or failed (i.e.separated). The results may be conveniently presented in a table. 8 Test report The test report shall include the following items. a) The results expressed in accordance with clause7. b
44、) If required, a statement of 1) the maximum force sustained by the joint for a chosen dwell time, 2) the minimum dwell time required for the joint to sustain a chosen force. c) Types of joint separation observed and the percentage of the total separated area that each represents. d) Description of
45、the adherends and their preparation (if any). e) Type of adhesive, application temperature and, if known, the coating thickness. f) Wiper plate temperature. g) Reference to this method of test (i.e.BS5131-1.8). h) Date of testing. Figure 3 Upper clampBS5131-1.8:1981 BSI 11-1999 5 Figure 4 Stages in
46、the formation and tensioning of a bondBS 5131-1.8: 1981 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is incorp
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