1、BRITISH STANDARD CONFIRMED OCTOBER 1987 BS2782-5: Method 540B: 1982 ISO4892:1981 Methods of testing Plastics Part 5: Optical and colour properties, weathering Method 540B: Methods of exposure to laboratory light sources, (xenon arc lamp, enclosed carbon arc lamp, open-flame carbon arc lamp, fluoresc
2、ent tube lamps) ISO title: Plastics Methods of exposure to laboratory light sources UDC 678.5/.8:678.01:535.68:620.193.6:628.9.04BS2782-5:Method 540B:1982 This British Standard, having been prepared under the directionof the Plastics StandardsCommittee, was published under the authority ofthe Board
3、of BSI and comes intoeffect on 26 February 1982 BSI 03-1999 The following BSI references relate to the work on this standard: Committee reference PLC/17 Draft for comment 78/55059 DC ISBN 0 580 12509 2 Amendments issued since publication Amd. No. Date of issue CommentsBS2782-5:Method 540B:1982 BSI 0
4、3-1999 i Contents Page National foreword ii 0 Introduction 1 1 Scope 1 2 Field of application 1 3 References 1 4 Principle 2 5 Apparatus 2 6 Test specimens 4 7 Procedure 5 8 Test report 6 Annex A Correlation of the effects of exposure to artificial light sources and exposure to natural daylight 7 An
5、nex B Use of blue dyed wool standards to measure light dosage 8 Annex C Spectral distribution of simulated solar radiation 10 Annex D Information concerning exposure to the light from fluorescent tube lamps 10 Figure 1 Spectral distribution Lamp A 12 Figure 2 Spectral distribution Lamp B 13 Figure 3
6、 Spectral distribution Lamp C 14 Figure 4 Spectral distribution Lamp D 15 Figure 5 Spectral distribution Lamp E 16 Table 1 Spray cycles 4 Table 2 Exposure stages 8 Table 3 Characteristics of fluorescent lamps 11BS2782-5:Method 540B:1982 ii BSI 03-1999 National foreword This method has been prepared
7、under the direction of the Plastics Standards Committee and is identical with ISO48921981 “PlasticsMethods of exposure to laboratory light sources” published by the International Organization for Standardization (ISO). It replaces method507B of BS2782:1970 which is being withdrawn. Terminology and c
8、onvention. The text of the international standard has been accepted as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is especially drawn to the following. The comma has been
9、 used throughout as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Cross-references International stand
10、ard Corresponding British Standard ISO1051978 BS1006:1978 Methods of test for colour fastness of textiles and leather (Technically equivalent) BS2782 Methods of testing plastics ISO293-1974 Method 901A:1977 Compression moulding test specimens of thermoplastic materials (Identical) ISO294-1975 Method
11、 910A:1977 Injection moulding test specimens of thermoplastic materials (Idential) ISO295-1974 Method 902A:1977 Compression moulding test specimens of thermosetting materials (Identical) ISO877-1976 Method 540A:1977 Determination of resistance to change upon exposure under glass to daylight (Identic
12、al) ISO2557/1-1976 Method 940A:1981 Preparation of test specimens of amorphous thermoplastic moulding material with a defined level of shrinkage in the form of parallelepipedic bars by compression moulding and injection moulding (Identical) ISO2557/2-1979 Method 940B:1981 Preparation of test specime
13、ns of amorphous thermoplastic moulding material with a defined level of shrinkage in the form of rectangular plates by injection moulding (Identical) ISO4582-1978 Method 552A:1981 Determination of the change in colour upon exposure under glass, natural weathering or artificial light (Identical) ISO4
14、607-1978 Method 550A:1981 Methods of exposure to natural weathering (Identical)BS2782-5:Method 540B:1982 BSI 03-1999 iii There are no corresponding British Standards for ISO3167 and ISO2818, referred to in6.2. As these references constitute informative matter only the validity of this British Standa
15、rd is not affected. A related standard to ISO28181980 is BS2782:Method 930A:1977 “Preparation of test specimens by machining”. There is at present no corresponding British Standard for ISO2579 but it is expected that it will be implemented within BS2782 without deviation. The technical committee has
16、 reviewed the draft provisions of ISO3557 and ISO3558, to which reference is made in clause3, and has decided that they are acceptable for use in conjunction with this standard. A related standard to ISO3558 is BS2782:Method 530B:1976 “Determination of the colour of near-white or near-colourless mat
17、erials”. Additional information. It should be noted that the apparatus using fluorescent tube lamps described in Annex D is in use in the United Kingdom and offers an economic and adequate alternative to the other three forms of apparatus described. Further information on the use of plastics in desi
18、gn engineering may be found in BS4618 “Recommendations for the presentation of plastics design data” Section 4.3:1974 “Resistance to colour change produced by exposure to light”. WARNING NOTE. This British Standard method, which is identical with ISO4892, does not necessarily detail all precautions
19、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 necessary provisions of a contract. Use
20、rs 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 to iv, pages1to 16 and a back cover. This standa
21、rd has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on theinside front cover.iv blankBS2782-5:Method 540B:1982 BSI 03-1999 1 0 Introduction The effects of light on the colour and other properties of plastics are of consider
22、able technical and commercial importance. Methods of exposing plastics to natural light are dealt with in ISO877 and ISO4607. There is, also, a need to gain information more rapidly by accelerated procedures and for this purpose specific artificial light sources are used. However, experience has sho
23、wn that many problems arise when trying to correlate the results obtained from testing using artificial light sources with those obtained in natural daylight (see Annex A). For some specific applications it may be possible to use certain fluorescent lamps as light sources. However, there is at prese
24、nt insufficient information on the reliability and repeatability of the results from such exposures to warrant inclusion of this type of apparatus in this International Standard. Investigations into these matters are being undertaken and it is hoped that as a result, fluorescent lamp light sources m
25、ay be incorporated in a future revision of this International Standard. Information on fluorescent lamps and their possible use is given in Annex D, which may assist interested parties in making their own investigations into the use of such devices. 1 Scope This International Standard specifies meth
26、ods for exposing specimens to laboratory light sources in order to assess changes produced by such exposure. The following types of light source are included: a) xenon arc lamp; b) enclosed carbon arc lamp; c) open-flame carbon arc lamp. Of the different light sources, the xenon arc is advantageous
27、in that it can, when correctly filtered and maintained, yield a spectrum most closely approximating to that of daylight. The carbon arc sources yield light which is considerably different from daylight and their use is decreasing. However, they have been found useful for some specific purposes and a
28、re still in considerable use in some countries; for this reason they have been included in this International Standard. This International Standard also specifies means of determining radiation dosage. For the method of determination of changes in properties after exposure, reference is made to ISO4
29、582. 2 Field of application Testing with laboratory light sources usually has one of the following purposes: a) to obtain results by accelerated testing under controlled, less variable conditions to indicate behaviour that would result from prolonged exposure to natural daylight; b) for control test
30、s on a material of known light resistance to establish that the level of quality of different batches does not vary from a known acceptable control. NOTEGuidance concerning the problems of correlation between the effects of exposure to artificial light sources and those obtained after exposure to na
31、tural light is given in Annex A. For a), changes in the specimens are determined at each of a number of light exposure stages, to give a sufficiently full picture of the performance throughout exposure. This method is also used, with interpolation if necessary, to find the amount of exposure needed
32、to produce a specified change in the material. For b), a suitable exposure stage is selected in advance from a knowledge of the expected light resistance of the material, and the change in the specimens is evaluated at this stage only. Alternatively, the exposure stage may be determined at which a d
33、efined change in the properties of the exposed test specimens occurs. 3 References ISO105, Textiles Tests for colour fastness. ISO293, Plastics Compression moulding test specimens of thermoplastic materials. ISO294, Plastics Injection moulding test specimens of thermoplastic materials. ISO295, Plast
34、ics Compression moulding test specimens of thermosetting materials. ISO877, Plastics Determination of resistance to change upon exposure under glass to daylight. ISO2557, Plastics Amorphous thermoplastic moulding materials Preparation of test specimens with a defined level of shrinkage. ISO2579, Pla
35、stics Instrumental evaluation of colour difference 1) . ISO2818, Plastics Preparation of test specimens by machining. ISO3167, Plastics Preparation and use of multipurpose test specimens. ISO3557, Plastics Recommended practice for spectrophotometry and calculation of colour in CEI systems 1) . 1) At
36、 present at the stage of draft.BS2782-5:Method 540B:1982 2 BSI 03-1999 ISO3558, Plastics Assessment of the colour of near-white or near-colourless materials 2) . ISO4582, Plastics Determination of the changes of colour and variations in properties after exposure to daylight under glass, natural weat
37、hering or artificial light. ISO4607, Plastics Determination of resistance to natural weathering. 4 Principle Specimens of the material to be tested are exposed to the light source together with means of assessing the light dosage. These may comprise one or more of the following: 4.1 Physical standar
38、ds which change in colour or other well-defined properties upon exposure to light, the degree of change indicating the light dosage. 4.2 Instrumental means of measuring irradiance and/or integrating this to give the light dosage over a period of time. 5 Apparatus 5.1 Laboratory light sources 5.1.1 G
39、eneral To improve the correlation with natural sunlight it is necessary that the spectrum of the light source be as near as possible to that of natural sunlight, particularly in the ultra-violet region, because some plastics are very sensitive to the spectral distribution of the radiation. However,
40、the intensity of the radiation will generally be higher than that of natural sunlight because of the need to accelerate the degradation processes in laboratory tests even though correlation with the simulated exposure condition may be weakened (see Annex A). Recommendations for the integrated irradi
41、ance and spectral distribution of simulated solar radiation for test purposes in the laboratory are given in CIE 3) publication No. 20 (TC22) 1972. The recommendation for the integrated irradiance for testing the deterioration resistance of materials and equipment exposed to natural radiation is 1kW
42、/m 2 (=100mW/cm 2 ) 10% The spectral distribution is given in Table 2.1 of CIE publication No.20 (TC22)1972 (reproduced herein as Annex C). Although this is the present standard, for various reasons it is not practicable to reproduce this radiation level exactly in either spectral distribution or in
43、tensity with presently available apparatus. Three laboratory light sources in current use are included in this International Standard. 5.1.2 Xenon arc lamp The xenon arc lamp emits radiation in a range which extends from below270 nm in the ultra-violet through the visible spectrum and into the infra
44、-red. For exposure tests, light from the lamp is filtered to reduce shorter wavelength emissions and also to remove as much of the infra-red as possible, so that radiation reaching specimens exposed to it has a spectral power distribution that closely matches sunlight. The facility may also be avail
45、able to reduce shorter wavelength energy further so that an alternative spectrum, similar to that of solar radiation as received behind window glass, may be obtained. These two modes of operation are often available on the same equipment, using different filter systems. The characteristics of xenon
46、arcs and filters are subject to changes in use due to ageing, and they shall be replaced at appropriate intervals. Further, they are subject to changes due to the accumulation of dirt, and they shall be cleaned at appropriate intervals as agreed between the interested parties. The irradiance at the
47、test specimen face in the wavelength range300 to890nm shall normally be1 000 200W/m 2 . If, exceptionally, other intensities are used, this shall be stated in the test report. Irradiance below300nm shall not exceed1W/m 2 . The irradiance shall not vary by more than 10% over the whole test specimen a
48、rea. 5.1.3 Enclosed carbon arc lamp The lamp comprises an arc formed between pure carbon rod electrodes, solid at one pole and cored at the other, and has automatic carbon feed. NOTEThe carbon rods in normal usage need changing about every24h, but rods of longer life which need changing after48h are
49、 now available and thus facilitate ease of running over week-ends and minimize the dark periods necessitated by the changing of carbons. The arc is enclosed in a globe made of heat-resistant glass transmitting less than1% light at275nm and shorter wavelengths, and approximately90% from370nm throughout the visible spectrum. The globe fits securely; it is clean and free from chips or cracks and it is so maintained at each change of electrodes. The characteristics of the glass filter are subject to changes in use
