1、BRITISH STANDARD BS3424-28: 1995 Testing coated fabrics Part 28: Method 31. Determination of specular glossBS3424-28:1995 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 come
2、s into effect on 15 November1995 BSI 06-1999 The following BSI references relate to the work on this standard: Committee reference PRI/78 Draft for comment 93/307661 DC ISBN 0 580 24537 3 Committees responsible for this British Standard The preparation of this British Standard was entrusted to Techn
3、ical Committee PRI/78, Coated fabrics, upon which the following bodies were represented: British Apparel and Textile Confederation British Nonwovens Manufacturers Association British Plastics Federation British Railways Board British Rubber Manufacturers Association Ltd. British Textile Technology G
4、roup Department of Health Department of the Environment (Building Research Establishment) Furniture Industry Research Association Home Office Industrial Safety (Protective Equipment) Manufacturers Association Made-Up Textiles Association RAPRA Technology Ltd. SATRA Footwear Technology Centre Society
5、 of Motor Manufacturers and Traders Limited Amendments issued since publication Amd. No. Date CommentsBS3424-28:1995 BSI 06-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Normative references 1 3 Definitions 1 4 Principle 1 5 Apparatus 1 6 Calibration of appar
6、atus 2 7 Preparation of test pieces 2 8 Testing atmosphere 2 9 Determination of specular gloss 2 10 Precision 3 11 Test report 3 Table 1 Specular gloss values for polished black glass 2 List of references Inside back coverBS3424-28:1995 ii BSI 06-1999 Foreword This British Standard has been prepared
7、 by Technical Committee PRI/78. The amount of visible light (i.ethe luminous flux) which is actually reflected by an object, compared with the intensity of light perceived by the viewer can be deceptively different, depending upon the colour or colour combination. Everything else being equal (i.e.hu
8、e, saturation, perceived colour) the amount of light reflected by the coating of a coated fabric will largely be determined by the smoothness of the polymer coating (assuming the coating to be of a solid colour and not translucent, in which event the constructional properties of the substrate would
9、play a significant part). Naturally the conspicuity of a coated fabric will be directly proportional to the amount of light it actually reflects, but this does not mean that coated fabrics that exhibit the same specular gloss will be equally conspicuous or that coatings exhibiting high ratios of spe
10、cular gloss will be more discernible. Some caution is therefore needed when selecting a coated fabric for a particular application. The apparatus and procedure specified is based upon ISO2813:1994. A British Standard does not purport to include all the necessary provisions of a contract. Users of Br
11、itish 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, pages1 to4, an inside back cover and a back cove
12、r. 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.BS3424-28:1995 BSI 06-1999 1 1 Scope This Part of BS3424 describes a method of test for determining the specular gloss, using a ref
13、lectometer geometry of20 or60 or85 of the polymeric coated surface of coated fabrics which are substantially smooth and are not deeply embossed. If the test is conducted on such structured surfaces no single value of specular gloss can be said to be representative of the coated fabric as a whole. 2
14、Normative references This Part of BS3424 incorporates, by dated or undated reference, provisions from other publications. These normative references are made at the appropriate places in the text and the cited publications are listed on the inside back page. For dated references, only the edition ci
15、ted applies, any subsequent amendments to or revisions of the cited publication apply to this Part of BS3424 only when incorporated in the reference by amendment or revision. For undated references, the latest edition of the cited publication applies, together with any amendments. 3 Definitions For
16、the purposes of this Part of BS3424 the following definitions apply. 3.1 surface gloss directionally selective reflecting properties responsible for the degree to which reflected highlights or the images of objects may be seen as superimposed on the surface 3.2 specular reflection reflection without
17、 diffusion in accordance with the laws of optical reflection, as in a mirror 3.3 specular reflectance the ratio of the luminous flux reflected in a specular manner, for a specified source and receptor angle, to the luminous flux of the incident light 3.4 specular gloss the ratio of the luminous flux
18、 reflected from an object in the specular direction, for a specified source and receptor angle, to the luminous flux reflected from glass with a refractive index of1.567 in the specular direction NOTETo define the specular gloss scale, polished black glass with a refractive index of1.567 is assigned
19、 the value of100 for geometries of20,60 and85. 4 Principle The coated fabric is placed on a level surface with the polymer coating to be measured uppermost. Light is directed onto the polymer surface and the reflected light is compared with that reflected by a reference standard. The result is repor
20、ted as a specular gloss value together with the angle at which the measurement was made. 5 Apparatus 5.1 Glossmeter, conforming to ISO2813. 5.2 Primary reference standard, comprising a clear fused-silica wedge, against which the black glass transfer standard is calibrated. 5.3 Transfer standard, com
21、prising either, highly polished black glass (see Table 1 for refractive index) or clear glass with the back and edges roughened and coated with black paint. The top surfaces shall be plane to within2fringes per cm, as measured by an optical interference method. NOTE 1Information on the effect of ref
22、ractive index on specular reflectance and specular gloss values is also given in Table 1. The glass surface shall be kept in a clean condition and free from surface scratches or damage. NOTE 2Black glass transfer standards are not as stable with time as is commonly assumed and should be recalibrated
23、 against a primary reference standard every12months. 5.4 Working standards, comprising ceramic tile, vitreous enamel, opaque glass or other uniform gloss materials calibrated against a primary reference standard(5.2) for an indicated area and direction of illumination. Working standards shall be che
24、cked periodically by comparison with primary reference standards. The working standards shall be uniform and stable, and shall be calibrated by technically competent organizations. At least two standards, of different gloss levels, shall be available for each glossmeter geometry. A black box or blac
25、k velvet shall be used for setting and checking the zero point of the display, which shall be conducted at the start of every period of operation.BS3424-28:1995 2 BSI 06-1999 6 Calibration of apparatus 6.1 Calibrate the apparatus at the start of every period of operation and during operation at inte
26、rvals sufficiently frequent to ensure that the instrument response is essentially constant. 6.2 Using either the primary reference standard(5.2), or the higher of two transfer standards(5.3), adjust the instrument reading to the correct or selected value in the upper part of the scale. If the black
27、glass reference standard(5.3) is used, ensure the instrument indicates the relevant specular gloss (as given in Table 1). Next, take a transfer standard(5.3) of known specular gloss for the angle being used, but having a value in the lower half of the scale, and make a measurement with the same cont
28、rol settings. NOTE 1If the reading for the working standard is within1gloss unit of its assigned value, the proportionality is in accordance with5.1. For tests at85 the reading for the working standard with a60 gloss lower than10gloss units, shall be within1gloss unit of its assigned value. For the
29、working standard with a60 gloss higher than10gloss units, the reading shall be within2gloss units of its assigned value. If this is not so, the instrument shall be adjusted or in accordance with the manufacturers instructions, and the calibration procedure repeated until the working standard is meas
30、ured within the required accuracy. NOTE 2It is assumed that the standards have not altered in any way or deteriorated by damage or distortion. The most common cause of incorrect results is lack of flatness, direction or failure to locate the surface in the correct plane for measurement. If a portabl
31、e instrument is used to measure materials which are not placed horizontally, the instrument should either be calibrated in the orientation in which it is to be used, or a check should be made that the calibration is valid in other orientations. 7 Preparation of test pieces Ensure that the coated sur
32、face to be tested is clean and flat and that any necessary cleaning does not damage the surface. 8 Testing atmosphere Ensure that the ambient atmosphere throughout the test is at least5C higher than the dew point for the relative humidity present (see BS3574). NOTEFor tests intended to be comparable
33、, it is important that the temperature at which the tests are conducted are the same. 9 Determination of specular gloss Calibrate the instrument using the working standard(5.4) and adjust the apparatus to give a reading corresponding to the relevant specular gloss given byTable 1 for the chosen angl
34、e of measurement. Take six readings, three in each of two directions at right angles, unless the surface is directionally textured, and report the mean and extreme values. If the surface is directionally textured, take six readings with the effect parallel to the plane of incidence and reflection of
35、 the instrument unless otherwise agreed. Report the mean and extreme values. Table 1 Specular gloss values for polished black glass Refractive index n Specular gloss at angles of incidence of 20 60 85 1.400 57.0 71.9 96.6 1.410 59.4 73.7 96.9 1.420 61.8 75.5 97.2 1.430 64.3 77.2 97.5 1.440 66.7 79.0
36、 97.6 1.450 69.2 80.7 98.0 1.460 71.8 82.4 98.2 1.470 74.3 84.1 98.4 1.480 76.9 85.8 98.6 1.490 79.5 87.5 98.8 1.500 82.0 89.1 99.0 1.510 84.7 90.8 99.2 1.520 87.3 92.4 99.3 1.530 90.0 94.1 99.5 1.540 92.7 95.7 99.6 1.550 95.4 97.3 99.8 1.560 98.1 98.9 99.9 1.567 a 100.0 a 100.0 a 100.0 a 1.570 100.
37、8 100.5 100.0 1.580 103.6 102.1 100.2 1.590 106.3 103.6 100.3 1.600 109.1 105.2 100.4 1.610 111.9 106.7 100.5 1.620 114.3 108.5 100.6 1.630 117.5 109.8 100.7 1.640 120.4 111.3 100.8 1.650 123.2 112.8 100.9 1.660 126.1 114.3 100.9 1.670 129.0 115.8 101.0 1.680 131.8 117.3 101.1 1.690 134.7 118.8 101.
38、2 1.700 137.6 120.3 101.2 1.710 140.5 121.7 101.3 1.720 143.4 123.2 101.3 1.730 146.4 124.6 101.4 1.740 149.3 126.1 101.4BS3424-28:1995 BSI 06-1999 3Table 1 Specular gloss values for polished black glass 10 Precision There are no data available from the material obtained during the preparation of th
39、is Part of BS3424 which would enable limits for repeatability and reproducibility to be obtained, but in view of problems associated with keeping coated fabric test pieces planar, it is unlikely that the mean results of tests from different laboratories obtained by different operators on test pieces
40、 from the same sample will be closer than four to six units (seeISO2813). 11 Test report The test report shall include the following information: a) the identification of the surface tested; b) the result of the test expressed as the mean and extreme values; c) the angle at which the test was carrie
41、d out; d) any other relevant information; e) the date(s) of the test; f) a reference to this standard. Refractive index n Specular gloss at angles of incidence of 20 60 85 1.750 152.2 127.5 101.5 1.760 155.2 128.9 101.5 1.770 158.1 130.4 101.6 1.780 161.1 131.8 101.6 1.790 164.0 133.2 101.6 1.800 16
42、7.0 134.6 101.7 a Primary reference standard.4 blankBS3424-28:1995 BSI 06-1999 List of references (see clause2) Informative references BSI publications BRITISH STANDARDS INSTITUTION, London BS 3574:1989, Specification for the controlled storage and packaging of vulcanized rubber and rubber products.
43、 ISO publications INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (ISO) Geneva. (All publications are available from BSI Customer Services.) ISO 2813:1994, Paints and varnishes Determination of specular gloss of non-metallic paint films at20, 60 and85. BS3424-28: 1995 BSI 389 Chiswick High Road Londo
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