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1、BRITISH STANDARD BS ISO 8257-2:1990 Implementation of ISO 8257-2:1990 Plastics Poly(methyl methacrylate) (PMMA) moulding and extrusion materials Part 2: Preparation of test specimens and determination of properties UDC 678.744.335 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+0
2、0:00 2006, Uncontrolled Copy, (c) BSI BS ISO 8257-2:1990 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 August 1995 BSI 12-1999 The following BSI ref
3、erences relate to the work on this standard: Committee reference PRI/35 Draft for comment 85/35535 DC ISBN 0 580 24641 8 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Technical Committee PRI/35, Speciality thermoplastics moulding materials
4、, upon which the following bodies were represented: British Plastics Federation British Telecommunications plc Department of Trade and Industry (National Physical Laboratory) ERA Technology Ltd. Electrical Installation Equipment Manufacturers Association (BEAMA Ltd.) Federation of the Electronics In
5、dustry Ministry of Defence Peratec Limited RAPRA Technology Ltd. Society of Motor Manufacturers and Traders Limited Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 8257-2:1990 B
6、SI 12-1999i Contents Page Committees responsibleInside front cover National forewordii Forewordiii Text of ISO 8257-21 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO 8257-2:1990 ii BSI 12-1999 National foreword This British Standard
7、reproduces verbatim ISO 8257-2:1990 and implements it as the UK national standard. This British Standard is published under the direction of the Sector Board for Materials and Chemicals whose Technical Committee PRI/35 has the responsibility to: aid enquirers to understand the text; present to the r
8、esponsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK. NOTEInternational and European Standards, as well as overseas standards, are available f
9、rom Customer Services, BSI, 389 Chiswick High Road, London W4 4AL. 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 immunit
10、y from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 4 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indic
11、ated in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 8257-2:1990(E) ii BSI 12-19
12、99 Contents Page Forewordiii 1Scope1 2Normative references1 3Preparation of test specimens1 4Conditioning3 5Determination of properties3 Table 1 Plastic melt temperature as a function of melt flow rate2 Table 2 Dependence of the constant a on viscosity number VN2 Table 3 Methods of test for PMMA mou
13、lding material and moulded test specimens4 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 8257-2:1990(E) BSI 12-1999iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bo
14、dies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO 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 organizatio
15、ns, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Draft International Standards adopted by the technical committees are circulat
16、ed to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 8257-2 was prepared by Technical Committee ISO/TC 61, Plastics. ISO 8257 consists of the following parts, under the general
17、title Plastics Poly(methyl methacrylate) (PMMA) moulding and extrusion materials: Part 1: Designation; Part 2: Preparation of test specimens and determination of properties. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed C
18、opy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 8257-2:1990(E) BSI 12-19991 1 Scope 1.1 This part of ISO 8257 specifies procedures for moulding test specimens of PMMA materials in a specified state and methods for measuring their properties. Any p
19、roperty listed in this part of ISO 8257 and referred to in combination with ISO 8257-1 shall be determined by the method referred to in this part of ISO 8257. 1.2 No figures are quoted for these properties. Those required for the designation of PMMA materials for moulding and extrusion are given in
20、ISO 8257-1. Other properties shall be determined by the appropriate methods referred to in this part of ISO 8257. 1.3 The values determined in accordance with this part of ISO 8257 will not necessarily be identical to those obtained using specimens of different dimensions and/or prepared by differen
21、t procedures. They may also be influenced by colorants and other additives. The values obtained for the properties of a moulding depend on the moulding compound, the shape, the test method and the state of anisotropy. The last-mentioned depends on the gating and the moulding conditions, for example
22、temperature, pressure or injection rate. Any subsequent treatment must also be considered, for example conditioning or annealing. 1.4 The thermal history and the internal stresses of the specimens may strongly influence thermal and mechanical properties and resistance to environmental stress crackin
23、g, but exert less effect on the electrical properties, which mainly depend on the chemical composition of the moulding compound. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 8257. At the time of pub
24、lication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 8257 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers
25、of currently valid International Standards. ISO 62:1980, Plastics Determination of water absorption. ISO 75:1987, Plastics and ebonite Determination of temperature of deflection under load. ISO 175:1981, Plastics Determination of the effects of liquid chemicals, including water. ISO 178:1975, Plasti
26、cs Determination of flexural properties of rigid plastics. ISO 179:1982, Plastics Determination of Charpy impact strength of rigid materials. ISO 180:1982, Plastics Determination of Izod impact strength of rigid materials. ISO 294:1975, Plastics Injection moulding test specimens of thermoplastic mat
27、erials. ISO 306:1987, Plastics Thermoplastic materials Determination of Vicat softening temperature. ISO 489:1983, Plastics Determination of the refractive index of transparent plastics. ISO/R 527:1966, Plastics Determination of tensile properties. ISO 537:1989, Plastics Testing with the torsion pen
28、dulum. ISO 604:1973, Plastics Determination of compressive properties. ISO 1133:1981, Plastics Determination of the melt flow rate of thermoplastics. ISO 1183:1987, Plastics Methods for determining the density and relative density of non-cellular plastics. ISO 1628-6:1990, Plastics Determination of
29、viscosity number and limiting viscosity number Part 6: Methyl methacrylate polymers. ISO 2039-1:1987, Plastics Determination of hardness Part 1: Ball indentation method. ISO 2557-1:1989, Plastics Amorphous thermoplastics Preparation of test specimens with a specified maximum reversion Part 1: Bars.
30、ISO 2818:1980, Plastics Preparation of test specimens by machining. ISO 8257-1:1987, Plastics Poly(methyl methacrylate) (PMMA) moulding and extrusion materials Part 1: Designation. ISO 8328:1989, Plastics Amorphous thermoplastic moulding materials Determination of maximum reversion. EN 2155-5:1989,
31、Aerospace series Test methods for transparent materials for aircraft glazing Part 5: Determination of visible light transmission. 3 Preparation of test specimens Injection moulding is the referee method for the preparation of test specimens and will become the only method included in the next revisi
32、on of this part of ISO 8257. Subclauses 3.3 and 3.3.1 on compression moulding are included for information only and will not appear in the next revision. Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 8257-2:1990(E) 2 BSI 12-1999 3.1 Pr
33、edrying of the moulding compound Before processing, the moulding compounds shall be predried for 24 h in an oven at 80 C. In cases of dispute, the manufacturers instructions shall be followed. 3.2 Preparation of test specimens by injection moulding The specimens produced under controlled conditions
34、shall be prepared by injection moulding, in accordance with ISO 294, using the following conditions: 3.2.1 Plastic melt temperature S see plastic (stock) temperature in ISO 294:1975 On the basis of the melt flow rate (MFR), as indicated in the designation code (see ISO 8257-1), the plastic melt temp
35、erature S (MFR) shall be selected in accordance with Table 1. Table 1 Plastic melt temperature as a function of melt flow rate EXAMPLE Moulding powder ISO 8257-PMMA, MLN, 108-030 S(MFR) = 250 C For moulding powders also characterized by the viscosity number (VN) in the designation code (see ISO 8257
36、-1), the melt temperature S (VN) may also be obtained, in degrees Celsius, from the relationship S(VN) = VST + 130 + a S (VN) shall be kept constant to within 3 C. Table 2 Dependence of the constant a on viscosity number VN EXAMPLE Moulding powder ISO 8257-PMMA,MLN,108-.-53 S(VN) = 108 + 130 + 10 =
37、248 C S (MFR) and S (VN) are parameters which do not differ noticeably for moulding powders, MFR values generally lying within the range 1 g/10 min (code-number 015) to 16 g/10 min (code-number 120). For moulding powders outside this range, S (VN) shall be used to ensure a comparable quality of the
38、test specimens. 3.2.2 Mould temperature (see ISO 294) The mould temperature M is given in degrees Celsius, by the equation M= VST 40 M shall be kept constant to within 3 C. EXAMPLE Moulding powder ISO 8257-PMMA, MLN,108-030-53 M= 108 40 = 68 C 3.2.3 Average injection velocity (see ISO 294) The injec
39、tion pressure shall be set in such a way that the average injection velocity is 250 mm/s 100 mm/s. 3.2.4 Hold pressure (see injection pressure in ISO 294:1975) The hold pressure shall be set in such a way that test specimens with only very slight sink marks are obtained. 3.2.5 Cooling time (see ISO
40、294) The cooling time shall be 50 s 5 s. 3.3 Preparation of test specimens by compression moulding Specimens in the basic state, i.e. almost free from molecular orientation, shall be prepared in accordance with ISO 2557-1 by compression moulding or by thermal relaxation of injection-moulded specimen
41、s. The specimens shall be considered to be in their basic state if the maximum reversion, measured in accordance with ISO 8328 (170 C, but 15 min, in air), does not exceed 5 %; the surface structure of the specimens and/or the values of intrinsic properties do not change as a result of heat treatmen
42、t. MFR cote-number S (MFR) 3a C 005 015 030 060 120 240 270 260 250 240 230 220 a It is important that S (MFR) is kept constant to within 3 C. where VSTis the Vicat softening temperature, in degrees Celsius, as given in the designation code; VNis the viscosity number, as given in the designation cod
43、e; ais a constant which depends on the viscosity number, as shown in Table 2; VN cote-number 435363738393 a01020304050 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 8257-2:1990(E) BSI 12-19993 3.3.1 Compression moulding The conditions
44、for compression moulding shall be adapted to the presses, moulds and moulding compounds being used. The following initial conditions are recommended: Temperature: 200 C Pre-heating time: 5 min Moulding pressure: 4 MPa Moulding time: 5 min Cooling rate: 10 C/min 5 C/min (under pressure) Demoulding at
45、: 60 C 3.3.2 Thermal relaxation The conditions for thermal relaxation shall be adapted to the presses, moulds and moulding materials being used. The following initial conditions are recommended: Temperature: 180 C Pressure: 1,5 MPa Relaxation time: 15 min Cooling rate: 10 C/min 5 C/min (under pressu
46、re) Demoulding at: 60 C 4 Conditioning When measuring the properties given in Table 3, the test specimens shall be given one of the following pre-treatments: Method 1: Annealing for 16 h at 80 C, followed by at least 24 h storage at 23 C and 50 % relative humidity. Method 2: Annealing for 16 h at 80
47、 C, followed by a cooling period of at least 1 h at 23 C in a desiccator. Testing shall be performed immediately after the samples are removed from the desiccator. In either method, if the specimens undergo deformation at 80 C, a temperature of (VST 25) C shall be used. This temperature shall be kep
48、t constant to within 3 C. 5 Determination of properties Properties shall be determined using the specimens and test methods specified in Table 3. All measurements shall be made at 23 C 2 C and (50 5) % relative humidity, unless otherwise specified in the relevant International Standard. Licensed Cop
49、y: sheffieldun sheffieldun, na, Mon Nov 27 08:07:13 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ISO 8257-2:1990(E) 4 BSI 12-1999 Table 3 Methods of test for PMMA moulding material and moulded test specimens PropertyUnit Test method Specimen dimensions mm Specimen statea ConditioningbRemarks Tests on moulding material Melt flow ratec Viscosity numberc Density g/10 min cm3/g g/cm3 ISO 1133 ISO 1628-6 ISO 1183 d d d