1、BRITISH STANDARD BS 2782-7: Method721A: 1988 Methods of testing Plastics Part 7: Rheological properties Method 721A: Determination of resin flow from resin impregnated glass fabric IMPORTANT NOTE. Before reading this method it is essential to read BS2782-0, issued separately UDC 678.01:678.066.2/.06
2、7.5:665.939.57:620.1:614.8BS2782-7:Method721A:1988 This British Standard, having been prepared under the directionof the Plastics StandardsCommittee, was published under the authority ofthe Board of BSI and comes intoeffect on 29 July1988 BSI 11-1999 The following BSI references relate to the work o
3、n this standard: Committee reference PLM/17 Draft for comment 86/43587 DC ISBN 0 580 16503 5 Amendments issued since publication Amd. No. Date of issue CommentsBS2782-7:Method721A:1988 BSI 11-1999 i Contents Page Foreword ii 1 Scope 1 2 Principle 1 3 Apparatus 1 4 Test pieces 1 5 Procedure 1 6 Expre
4、ssion of results 2 7 Test report 2 Table 1 Nominal platen temperature and pressure 2 Publications referred to Inside back coverBS2782-7:Method721A:1988 ii BSI 11-1999 Foreword This method has been prepared under the direction of the Plastics Standards Committee. It describes a procedure for the dete
5、rmination of the flow of resin under heat and pressure from resin impregnated glass fabric. This method supersedes and is a revision of method105D of BS2782:1970 which is being withdrawn. The principal changes from method105D are as follows. a) This method is more similar to IEC249-3-1. In particula
6、r, for testing epoxide resins, the platen temperature has been increased from160 C to170 C. b) The permissible deviations for temperature of the platen have been changed from 5 C to 3 C. c) The area of test piece removed after cure has been changed from2500mm 2to5000mm 2to align with IEC249-3-1. Thi
7、s method is suitable for testing the product known as “pre-impregnated” glass fabric, i.e.resin impregnated glass fabric that can be purchased as such and used for the manufacture of laminated sheets and mouldings. This method is related to and differs from those described in IEC publication249-3-1:
8、1981 and in BS4584-11:1977 (which is dual-numbered with IEC249-3:1973), principally in the following respects: 1) the use of this method is not restricted to epoxide materials for printed circuits: this method therefore provides additional temperatures and pressures for use with other materials; 2)
9、this method uses two test pieces which may indicate a variation across the width of the material which cannot be assessed in accordance with IEC249-3-1 or BS4584-11:1977; 3) the term “epoxy resin” is used in place of “epoxide resin”, for consistency with BS1755-1. WARNING NOTE. This method does not
10、necessarily detail all precautions necessary to meet the requirements of the Health and Safety at Work etc. Act1974. Attention should be paid to any appropriate safety precautions and the method should be operated only by trained personnel. A British Standard does not purport to include all the nece
11、ssary 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 obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages
12、1 and 2, 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 the inside front cover.BS2782-7:Method721A:1988 BSI 11-1999 1 1 Scope This method describes a procedure for a
13、ssessing the flow of resin under heat and pressure from glass fabric impregnated with polyester, epoxy or silicone resin. By appropriate choice of moulding conditions the method may be applicable to all types of resin impregnated substrates, e.g.paper, cotton fabric, cotton/synthetic fibre fabric, g
14、lass mat, glass rovings and also other resins, e.g.phenolic, melamine and polyamide. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Principle A test piece, consisting of superimposed layers of the material under test, is pressed between heated
15、steel plates under appropriate conditions of temperature, pressure and time. The amount of resin lost in the moulding operation, determined and expressed as a percentage of the original mass of the test piece, is reported as the resin flow. 3 Apparatus 3.1 Press with heated platens, capable of maint
16、aining the temperature to within 3 C of the required temperature, which is normally within the range120 C to180 C. 3.2 Stainless steel plates, not less than125mm 125mm and1.6 0.8mm thick. 3.3 Balance, accurate to0.01g. 3.4 Release agent, suitable for the material under test. 4 Test pieces 4.1 Form a
17、nd dimensions Each test piece shall consist of a sufficient number of square pieces of the fabric with sides each1001mm, cut on the bias, to aggregate a total mass of10g to30g and stacked together with their edges in careful alignment. The fabric pieces may be fastened together with a staple or by o
18、ther suitable means, to keep the edges in alignment. NOTEThe test piece is defined in terms of aggregate mass in order to accommodate the wide range of possible materials. At least four pieces of fabric per test piece should be used in order to get a satisfactory result, and it is inadvisable to use
19、 more than20 pieces of fabric for materials having very high resin content and flow because of difficulties in carrying out the test. These restrictions define a satisfactory test piece for most materials. 4.2 Position of fabric pieces The fabric pieces which form the test pieces shall be cut from t
20、he material under test as specified in the relevant British Standard. Where there is no British Standard for the material under test and the material is in the form of a roll, each fabric piece shall be taken from a position at least25mm away from any edge or selvage, and shall be cut from positions
21、 along a line normal to the warp of the fabric, with the diagonals of the fabric piece parallel to the warp and weft threads. The required number of fabric pieces to make one test piece shall be taken from the area to one side of the centreline and the fabric pieces for the other test piece shall be
22、 taken from the area on the other side of the centreline of the fabric. 4.3 Number of test pieces Two test pieces shall be used. 5 Procedure 5.1 Make all weighings required by the procedure to the nearest0.01g. 5.2 Weigh the test piece to determine its mass (M 1 ). 5.3 Treat the stainless steel plat
23、es with the appropriate release agent. Place the test piece centrally between the steel plates to form an assembly. 5.4 Preheat the platens of the press until maintained within 3 C of the relevant temperature for the material, as given in Table 1. 5.5 Insert the assembly of steel plates and test pie
24、ce centrally on the heated platens of the press. Apply the relevant pressure for the material, as given in Table 1, within5s of the insertion of the assembly. Maintain the pressure within 10%of the nominal pressure until there is no further flow of resin, or for10min, whichever is longer. 5.6 Remove
25、 the cured test piece and allow to cool to room temperature. 5.7 Either: a) remove the flash cleanly and weigh the laminate to determine its mass (M 2 ); or if this is not possible, b) cut a piece of area5000mm 2in the form of a square or disc from the central area of the laminate and weigh the piec
26、e to determine its mass (M 3 ).BS2782-7:Method721A:1988 2 BSI 11-1999 Table 1 Nominal platen temperature and pressure 6 Expression of results 6.1 Calculate the percentage of mass lost from the test piece as resin during the moulding operation by using one of the following equations as applicable. 6.
27、2 Express the resin flow from the material under test as the arithmetic mean of the results obtained from the two test pieces. 7 Test report The test report shall include the following: a) a complete identification of the material tested, including type, source, manufacturers code number and previou
28、s history; b) a reference to this British Standard, e.g.BS2782:Method721A:1988; c) the temperature and pressure used; d) a reference to the relevant British Standard for the material under test, if any; e) the type of resin; f) the individual results for each test piece with the suffix (M 2 ) if det
29、ermined in accordance with5.7 a), or (M 3 ) if determined in accordance with5.7 b); g) the resin flow. Resin Platen temperature a Pressure a(force per unit area of the test piece) C MPa Polyester 120 1.4 Epoxy 170 1.5 Silicone 175 1.4 for low pressure laminates 6.9 for high pressure laminates a Thes
30、e values apply to the materials unless values are specified in the relevant material specification in a BritishStandard. a) If measured in accordance with5.7 a): resin flow = (1) b) If measured in accordance with5.7 b): resin flow = (2) M 1 M 2 () M 1 -100 M 1 2M 3 () M 1 -100 BS2782-7:Method721A:19
31、88 BSI 11-1999 Publications referred to BS1755, Glossary of terms used in the plastics industry 1) . BS1755-1, Polymer and plastics technology. BS2782, Methods of testing plastics. BS2782-0, Introduction. BS4584, Metal-clad base materials for printed wiring boards 1) . BS4584-11, Bonding sheet mater
32、ial for use in the fabrication of multilayer printed boards: EPGC11. IEC249, Base materials for printed circuits 1) . IEC249-3, Special materials used in connection with printed circuits. IEC249SpecificationNo1, Prepreg for use as bonding sheet material in the fabrication of multilayer printed board
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