ISO 8781-3:1990 顔料と増量剤—分散特性の評価方法—パート3：光沢の変化からの評価 | ページ 2

Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.

International Standard ISO 8781-3 was prepared by Technical Committee ISO/TC 35, Paints and varnishes.

ISO 8781 consists of the following parts, under the general title Pigments and extenders — Methods of assessment of dispersion characteristics:

• Part 1: Assessment from the change in tinting strength of coloured pigments
• Part 2: Assessment from the change in fineness of grind
• Part 3: Assessment from the change in gloss

Annex A forms an integral part of this part of ISO 8781.

Introduction

The development of specular gloss of a pigment in a dispersion is dependent primarily on the amount of work done in the preparation of the dispersion of the pigment in a binder system and the ratio of pigment to the binder system. The ease with which the ultimate specular gloss of a dried coating of the dispersion is achieved may therefore be used to assess the dispersion characteristics of the pigment. Thus, if the ultimate specular gloss can be attained easily, the pigment is considered to be readily dispersible.

The method described consists essentially of three steps:

• a) preparation in stages of a range of dispersions of the pigment in accordance with an appropriate part of ISO 8780;
• b) preparation of dried films of the dispersions and measurement of the specular gloss;
• c) determination of the rate of development of the specular gloss as a function of the amount of work done (the latter is related to the incremental stages of dispersion).

The rate of development of specular gloss is assessed graphically.

1 Scope

This part of ISO 8781 specifies a method for assessing, on the basis of specular gloss, the dispersion characteristics of pigments which have been dispersed by one of the methods of dispersion described in ISO 8780. It should be read in conjunction with ISO 8780-1.

The method is of general use for comparing similar pigments, for example a test pigment against an agreed reference pigment.

2 Normative references

The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO 8781. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this part of ISO 8781 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.