1、CEN EN*IS0*787- 24 95 H 3404589 OLL7375 905 _ -. A - BRITISH STANDARD w.XG= General methods of test for pigments and extenders Part 24. Determination of relative tinting strength of coloured pigments and relative scattering power of white pigments - Photometric methods The European Standard EN IS0 7
2、87-24 : 1995 has the status of a ritish Standard ICs 87.060.10 BS EN IS0 787-24 : 1995 CEN EN*IS0*787- 24 95 m 3YOY589 OLL7376 841 m National foreword This Part of BS 3483 has been prepared under the direction of the Pigments. Paints and Varnishes Standards Committee. it is identical with IS0 787/24
3、-1985 General methods of test for pigments and extenders - Part 24 : Determination of relative tinting strength of coloured Pigments and relative Scattering Power of white pigments - Photometric methods published by the International Organization for Standardization (ISO). in 1995 the European Coini
4、iutk foi- Staridarduatiori (CEN) accepted IS0 787-24 : 1985 as European Standard EN IS0 i8-24 : 1995. As u corsequeiice of implementing the European Stantlard this Biitisti Stanilard is renuriikred as US EN IS0 (817-24 and my reference to 13s :%IS3 : lart Ati should be read as a refeiriiw to HC EN I
5、S0 78-24. It has been assumed in the drafting of this standard that the execution of its provisions will be entrusted to appropriately qualified and experienced people. Terminology and conventions. The text of the international standard has been approved as suitable for publication as a British Stan
6、dard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it IS current practice to use a full point on the baseline as the
7、 decimal marker. Wherever the words International Standard appear, referring to this standard. they should be read as British Standard, this part of IS0 787 should be read as this Part of flS 3483. and IS0 787/24 should be read as BS 3483 : Part A6. B r itish Stan dards 1 nst tu tion A CEN EN*ISO*78
8、7- 24 95 3404589 0337377 788 D EUROPFAN STANDARD NOFUVE EUR0PEE”E EuROPmE NORM A- EN IS0 787-24 August 1995 ICs 87.060.10 Descriptors: Paints, pigments, tests, detemunation, colouring power, photometric method English version General methods of test for pigments and extenders - Part 24 Determination
9、 of relative tinting strength of coloured pigments and relative scattering power of white pigments- Photometric methods (IS0 787-24 : 1985) Mthodes gnrales dessai des pigments et matires de charge - Partie 24 Dtermination du pouvoir colorant relatif des pigments colors et du pouvoir diffusant relati
10、f des pigments blancs - Mthodes photomtriques Allgemeine mufverfahren fr Pigmente und Fullstoffe - Teil 24 Bestimmung der relativen Farbstrke von Buntpigmenten und des relativen Streuvermgens von WeiBpigmenten Photometrische Verfahren (IS0 787-24 : 1985) (IS0 787-24 1985) This European Standard was
11、approved by CEN on 199503-23. CEN members are bound to comply with the CENXENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national s
12、tandards may be obtained on application to the Centrai Secretariat or to any CEN member. This European Standard exiss in three official versions (Enghsh, French, German). A version in any other ianguage made by translation under the responsibility of a GEN member into its own language and notified t
13、o the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Fniand, France, Germany, Greece, Iceland, ireand, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN E
14、uropean Committee for Standardization Comit Europen de Normalisation Europisches Komitee fiu Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels O 1995 All rights of reproduction and communication in any form and by any means reserved in all countries to GEN and its members Ref. NO. EN
15、IS0 787-24 : 1995 E CEN EN*IS0*787- 24 95 3404589 OLL7378 bL4 Page 2 EN IS0 787-24 : 1995 Foreword The text of the International Standard horn Iso/M= 35, Paints and varnishes, of the Intedonal Organization for Standardization USO) has been taken over as a European Standard by the Technical Committee
16、 CENRC 298, Pigments and extenders. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by Febniary 1996, and contlicting national standards shall be withdrawn at the latest by February 1996. According t
17、o the CEN/CENELEC Internai Regulations, the foilowing countries are bound to implement this European Standard Austia, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Itay, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. NOTE. Normat
18、ive references to international publications are given in annex ZA (normative). !I CEN EN*ISO*787- 24 95 m 3404589 OLL7379 550 m BS 3483 : Part A6 : 1988 Cross-references International standard Corresponding British Standard IS0 591 -1977 BS 1851 : 1978 Specification for titanium dioxide pigments fo
19、r paints (Identical) BS 3483 Methods for testing pigments for paints Part 66 : 1982 Determination of matter volatile at 105 OC (Identical) Part C4 : 1982 Determination of pH value of an aqueous suspension (Identical) Part A4 : 1988 Determination of relative tinting strength and colour on reduction o
20、f coloured pigments using visual comparison (Identical) Part A5 : 1974 Comparison of lightening power of white pigments (Technically equivalent) Part B9 : 1980 Determination of density relative to water (using a centrifuge) ( I den tica I ) BS 4726 : 1986 Methods for sampling raw materials for paint
21、s and varnishes (Identical) BS 3900 Methods of test for paints Part C6 : 1983 Determination of fineness of grind (Identical) 6s 2782 Methods of testing plastics Method 730B : 1978 Determination of the viscosity of polymers in the liquid, emulsified or dispersed state using a rotational viscometer wo
22、rking at a defined shear rate (I den ti cal BS 1795 : 1976 Specification for extenders for paints (Identical) BS 6782 Binders for paints Part 3 : 1987 Method for determination of acid value (titrimetric method) d) (Identical) Part 4 : 1987 Method for determination of hydroxyl value (titrimetric meth
23、od) (Identical) IS0 787/2-1981 IS0 787/9-1981 IS0 787/16-1986 IS0 787/17 -1 973 (published as Parts XII I to XVIII) IS0 787/23-1979 IS0 842-1984 IS0 1524-1 983 IS0 3219-1977 IS0 3262-1 975 IS0 3682-1983 IS0 4629-1 978 i b) same type dispersed in an alkyd resin without a drier. the scattering power o
24、f two white pigments of the These methods of test provide an instrumental alternative to those described in IS0 787/16 and IS0 787/17 respectively, avoiding the necessity of visual matching. NOTES 1 coloured pigments that on reduction differ greatly in colour. 2 When one of these general methods is
25、applicable to a given pigment, only a cross-reference to the appropriate method should be included in the International Standard relating to that pigment, indicating any detailed modification which may be needed in view of the special properties of the product in question. Only when the appropriate
26、method in this part of IS0 787 is not applicable to a particular product should different photometric methods for determination of relative tinting strength and determination of relative scattering power be specified. This Intemational Standard is not appropriate for the comparison of 2 References I
27、S0 591, Titanium dioxide pigments for paints IS0 787, General metbods of test for pigments and extenkm - Part 2 : Determination of matter volatile at 105 oc. Part9: Determination of pH value of an aqueous suspension. Part IO I Determination of density - Pyknometer method. Part 16 I Determination of
28、relative tinting strength (or equivalent colouring valuel and colour on reduction of coloured pigments - Visual com,oarison method. Part 17 : Comparison of lightening power of white pigments. Part 23 : Determination of density (using a centrifuge to remove entrained airl. IS0 842, Raw materials for
29、paints and varnishes - Sampling. IS0 1524, Paints and varnishes - Determination of fineness of grind. Is0 3219, Plastics - Polymers in the liquid, emulsified or dispersed state - Determination of viscosity with a rotational viscometer working at defined shear rate. IS0 3262. Extenders for paints. IS
30、0 3682, Binders for paints and varnishes - Determination of acid value - Titrimetric method. IS0 4629, Binders forpaints and varnishes - Determination of hydroxyl value - Titrimetric method. 11 IS0 4652, Rubber compounding ingredients - Carbon black - Determination of specific surface area - Nitroge
31、n adsorotion methods. IS0 6209. Rubber com,oounding ingredients - Carbon black - Determination of solvent extractable material. li In course of Dreparation. (Revision of IS0 629-1978,) 3 CEN EN*IS0*787- 24 95 m 3404589 OLL738L LO9 m BS 3483 : Part A6 : 1988 3 Definitions 3.1 For coloured and black p
32、igments 3.1.1 tinting strength : The abilitv of a pigment (see the note) to absorb incident light, thereby having the power to colour or darken, for example, a white paint in which it is incor- porated. NOTE - Althouqh the properties tested are strictly those of the pigmented binder, absorption and
33、scattering by the binder are rela- tively small and it is assumed in this International Standard that the material under test is the dispersed pigment. 3.1.2 spectral absorption coefficient K(1) : The fraction of the diffusely incident spectral radiant flux of wavelength 1 that is absorbed in an ele
34、mentary layer within a material, divided by the thickness of the layer (Kubelka-Munk analysis). NOTE - KO.) is a measure of the tinting strength of coloured pigments in a material and is expressed in units of reciprocal film thickness. 3.1.3 absorbance index K,i4 : The spectral absorption coefficien
35、t of the pigmented binder divided by the pigment concentration C, : where C, is the pigment concentration, for example, ex- pressed as the ratio by mass of pigment to binder. 3.1.4 relative tinting strength KrA) : The ratio of the ab- sorbance index of the test sample K,(A) to that of an agreed refe
36、rence pigment KD2(At, expressed as a percentage : 3.2 For white pigments (21 3.2.1 scattering power : The ability of a pigment (see the note to 3.1.1) to diffuse incident light, thereby having the power to confer opacity and lightness to, for example, a paint in which it is incorporated. 3.2.2 spect
37、ral scattering coefficient S(1) : The net transfer of spectral radiant flux of wavelength L in the outward direction from an elementary layer within a body of material illuminated from outside, divided by the product of the thickness of the layer and the difference between the magnitude of the flux
38、in the two directions through the layer (Kubelka-Munk analysis). NOTE - Til I is a measure of the scattering power of white pigments in a material and i5 exmessed in units of reciprocal film thickness. 3.2.3 scattering index S,(A) : The spectral scattering co- efficient of the pigmented binder divid
39、ed by the pigment concentration C, (see 3.1.31 : (31 3.2.4 relative scattering power .S,(A) : The ratio of the scat- tering index of the test sample S,A) to that of an agreed reference pigment Sfl,(Al, expressed as a percentage : . . . (41 3.3 reflectivity o, : The reflectance of a paste or a paint
40、film of such thickness that further increase in thickness gives no further change in reflectance. The reflectivity e KIS, is the KIS value corresponding to 9, or R, of the agreed reference pigment. 5 Materials and equipment 5.1 White pigment paste, with the following composition - plying with the re
41、quirements of IS0 591; 40 parts by mass of titanium dioxide, Grade R2, com- - 56 parts by mass of alkyd resin (see note 3 to 5.2): - 4 parts by mass of calcium stearate. Using a spatula, mix well so as to achieve preliminary wetting of the solids. Then grind on the triple-roll mill (6.1) until the p
42、article size is les than 5 vm when tested on a fineness-of-grind gauge (see IS0 1524). Store the paste in an airtight container, preferably a collapsible tube with a screw cap. 5.2 Black pigment paste (see note li, prepared as follows. 5.2.1 Mix 18.7 parts by mass of carbon black pigment (see note 2
43、) with 81,3 parts by mass of alkyd resin (see note 3) by use of a spatula. Pass the mixture six times through the triple- roll mill (6.11 to achieve a unifonn fine dispersion. 5.2.2 Mix 3,25 g of the intermediate paste prepared as described in 5.2.1 with 91,H g of alkyd resin (see note 3) and 5.11 g
44、 of fumed silica (see note 4); pass the mixture once through the triple-roll mill. NOTES 1 The black pigment paste is available commercially. lhe mixture specified in 5.2.2 is suitable for testing at a pigment vdume concen- tration of 17 %. 2 Carbon black pigment of the lampblack type complying with
45、 the following requirements : Test method nigrometer index value 102 IS0 78712 volatile matter content toluene extractable matter 0.15 % max. IS0 6209 specific surface area (BETI 20 m2/g IS0 4652 pH value 7 IS0 78719 about 1 % 3 Alkyd resin, based on a mixture of 63 % Iin!m) linseed oil and 23 % rn/
46、rn) phthalic anhydride, and complying with the following requirements : Test method acid value 15 mg KHIg IS0 5682 mar. viscosity (solvent free) 7 to 10 Pa.s IS0 3219 hydroxyl content about 40 mg KOH/g IS0 4629 This alkyd resin is commercially available. 4 Fumed silica complying with the following r
47、equirements : Test method specific surface area (BET) pH value of a 4 % 175 to 225 m2/g dispersion in water 3.6 to 4.5 IS0 787/9 6 Apparatus 6.1 Triple-roll mill. 6.2 Automatic muller, with ground glass plates, preferably water cooled (see the note), of diameter 180 to 250 mm to which a variable but
48、 known force of up to about 1 kN may be applied. The driven glass plate should have a speed of rotation of between 70 and 120 rlmin and the apparatus should have an arrangement for pre-setting the number of revolutions in multiples of 25. Pre-condition new muller plates by milling a pigment in a sui
49、table binder (system) for 1 o00 revolutions with a load applied to the plates. Remove the paste and discard. Before use, check the surface of both plates for freedom from score marks, freedom from polished areas and for an even opaque appearance. NOTE - If the automatic muller does not have water-cooled plates. take care that the temperature during the grinding operation does not rise by more than 10 OC. 6.3 Paste film holders, for example a suitable dish, for each test dispersion to support a paste film of about 250 um thickness; it may hav
