ISO 3688 pdf download

ISO 3688 pdf download.Pulps — Preparation of laboratory sheets for the measurement of diffuse blue reflectance factor (ISO brightness) 1 Scope This International Standard specifies two procedures for the preparation of laboratory sheets prior to measuring the diffuse blue reflectance factor (ISO brightness). One is the traditional procedure based on preparation of sheets in a Büchner funnel using a filter paper or a wire screen. ln the other procedure, the sheets are prepared in a standard sheet former (conventional or Rapid Köthen). Details of the subsequent measurement procedure are given in ISO 2470. It is applicable to all wood pulps and to most other types of pulp. Pulps with very long fibres, such as those made from unshortened cotton, flax and similar materials, shall be reduced to a suitable fibre length before testing by this method. This International Standard shall be used in conjunction with ISO 2469 and ISO 2470. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 2469:1 994, Paper, board and pulps — Measurement of diffuse reflectance factor. ISO 2470:— 1 ) , Paper and board — Measurement of diffuse blue reflectance factor (ISO brightness). ISO 5263:1 995, Pulps — Laboratory wet disintegration. ISO 5269-1 :1 998, Pulps — Preparation of laboratory sheets for physical testing — Part 1 : Conventional sheet- former method. ISO 5269-2:1 998, Preparation of laboratory sheets for physical testing — Part 2: Rapid-Köthen method. 3 Reagents During the sheet preparation, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity, free from colouring matter and from iron and copper ions. NOTE Distilled water is used to ensure that the brightness of the sample is not affected by the water.3.1 Sodium hydroxide, (NaOH), approximately 0,1 mol/l solution, containing 4,0 g of sodium hydroxide per litre. 3.2 SuIfuric acid, (H 2 SO 4 ), approximately 0,05 mol/l solution, containing 2,8 ml of sulfuric acid ( ρ 1 ,84 g/ml) per litre, or acetic acid, w (CH 3 COOH) = 1 0 %...