1、STD-BSI BS EN L2877-q-ENGL 2000 Lb2qbb 0822704 2b BRITISH STANDARD Colouring materials in plastics - Determination of colour stability to heat during processing of colouring materials in plastics - Part 4: Determination by two-roll milling The European Standard EN 128774 1999 has the status of a Bri
2、tish Standard ICs 83.040.30 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW 5s EN 12877-4:2000 STD-BSI BS EN 12877-q-ENGL 2000 = Lb29bbS 0822705 b2 BS EN 12877-4:2000 Amd. No. National foreword Date Comments This British Standard, having been prepared under the direction of th
3、e Sector Committee for Materiais and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 January 2000 O BSI 01-2000 ISBN O 580 35857 7 This British Standard is the Englsh ianguage version of EN 129774: 1999. “he UK participation in its preparation was
4、entrusted to Technical Committee SW1, Pigments, which has the responsibility to. - aid enquirers to understand the te* - present to the responsible European committee any enquiries on the - monitor related international and European developments and promulgate interpretatioq or proposals for change,
5、 and keep the UK interests informed; them in the UK. A list of organizations represented on this committee can be obtained on request to its secretaxy. Cross-references The British Standards which implement int - ratio of peripheral speeds: between 1 : 1 and 1 : 1,l 5.2 Plate press, provided with a
6、heating and cooling system. 5.3 Spectrophotometer or tristimulus colorimeter, for colour measurements in accordance with IS0 7724-2. 6 Sampling See EN 12877-1. 7 Test specimens 7.1 Form and dimensions The quantity of material shall be sufficient to fill the gap between the rolls and provide the requ
7、ired bead diameter Unless otherwise specified or agreed, test specimens of dimensions 50 mm x 50 mm x 1 mm, suitable for colorimetry, shall be used. 7.2 Concentration of colouring material The colouring material shall be tested in reduced shade (7.2.1) and/or in full shade (7.2.2). 7.2.1 For testing
8、 in reduced shade, the concentration of the colouring material in the test medium shall correspond to: a) 113 standard depth of shade (SD) in accordance with EN 12877-1 :1999, annex A; or b) 1/25 standard depth of shade (SD) in accordance with EN 12877-1:1999, annex A; or c) an agreed reduction rati
9、o. For a test specimen thickness of 1 mm 5 % of titanium dioxide pigment is necessary to obtain full hiding. 7.2.2 For testing in full shade, the concentration of the colouring material in the test medium shall correspond to 7.2.1 a). Alternatively, a concentration of 0,l % (to be preferred for orga
10、nic pigments and dyestuffs), or 2 % (to be preferred for inorganic pigments) or another agreed appropriate concentration shall be taken. 8 Procedure Prepare milled sheets on the two-roll mill from the colouring material to be tested and the agreed plastics material. In the case of plasticized polyvi
11、nyl chloride use a temperature of (160 f 5) OC, a gap width of 0,2 mm to 0,4 mm and a total milling time of 8 min including plastification. Cut and fold the sheet repeatedly to achieve adequate dispersion of the colouring material. Take a sample from one of the sheets and prepare a test specimen fro
12、m it by heat pressing at 170 “C for 1 min, for use as a reference specimen. Set the roll surface temperatures for PVC, to between 180 OC and 185 OC and for PVC, to between 190 OC and 195 OC. Process a sufficient number of sheets so that the recommended minimum bead diameter is achieved (see 51), whi
13、lst setting the roller gap to produce a sheet of uniform thickness of about I mm. Start timing and mill the material, limiting the width of the sheet by frequent cutting to one half and by reversal and lateral rolling, to prevent the material from running up onto the roll guides. OBSI 01-2000 STD*BS
14、I BS EN 12877-q-ENGL 2000 = LhZlbb7 0822709 V08 Page 4 EN 12877-4: 1999 Take samples after 10 min and 20 min milling time. Afler a further period of 10 min (total test period 30 min) draw off the mili sheet and take a further sample. Prepare test specimens from each sample by heat pressing at 170 OC
15、 for 1 min, using sufficient pressure to achieve a smooth surface. WARNING - Attention is drawn to the need for efficient fume extraction when testing plasticized polyvinyl chloride on an open mill at elevated temperatures. Compare the colour of the test specimens with that of the reference specimen
16、 either colorimetrically or visually. NOTE Colouring materials such as C.l. Pigment Red 48, 53 and 57 and deyestuffs can change colour reversible after heat treatment and the specimens should be maintained at room temperature for at least 16 h before assessment. If colour measurement is specified, p
17、roceed in accordance with IS0 7724-2:1984,4.1.1, and IS0 7724-3. For visual comparison, use the grey scale specified in EN 20105-A02. 9 Expression of results Express the test results either as a colour difference in accordance with IS0 7724-3, or as a step of the grey scale, together with the direct
18、ion of any colour change. IO Test report The test report shall contain at least the following information: a) a reference to this European Standard (EN 128774); b) all details necessary to identify the colouring material tested; c) ali details necessary to identify the test medium together with any
19、other additives used, including the titanium dioxide pigment; d) all details necessary regarding the preparation of the test specimens and the execution of the test (temperature and test duration); e) the chosen standard depth) of shade or full shade and the concentrations of the colouring material
20、tested; 9 if dour measurement has been specified: type of spectrophotometer or tristimulus colorimeter as well as standard illuminant and standard observer used; g) conditions of pressing the treated test specimens; h) the resul of the test, as indicated in clause 9; i) ali visual observations, for
21、example discolouration of the test medium or blooming of the colouring material; j) any deviation from the test method specified; k) the date of the test. 11 Precision Statistical data are not appropriate. OBSI 01-2000 BS EN 1287742000 BSI 389 Chiswick High Road London w4 4AL BSI - British Standards
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