GB/T 23981.2-2023Paints and varnishes—Determination of hiding power—Part 2:Method of black and white grid panel (English PDF)

Foreword

This document complies with the provisions of GB/T 1.1-2020 "Standardization Work Guidelines Part 1: Structure and Drafting Rules of Standardization Documents" Drafting.

This document is Part 2 of GB/T 23981 "Determination of Hiding Power of Paints and Varnishes". GB/T 23981 has released the following part.

---Part 1: Determination of contrast ratio of white and light-colored paint;

---Part 2: Black and white grid method.

This document replaces GB/T 1726-1979 "Method for determination of hiding power of coatings". Compared with GB/T 1726-1979, except for structural adjustment and compilation In addition to editorial changes, the main technical changes are as follows.

a) Increased scope (see Chapter 1);

b) Added terms and definitions (see Chapter 3);

c) Changed the requirements for glass panels (see 4.2, Chapter 1 of the 1979 edition);

d) Added cup requirements (see 4.3);

e) Changed the graduation value of the balance (see 4.4, Chapter 1 of the 1979 edition);

f) Changed the requirements for black and white grid glass plates; changed the spraying method of black and white grid boards to black and white grid stickers, and added tests for black and white grids requirements (see 4.5, 4.6, Chapter 1 of the 1979 edition);

g) Changed the requirements for camera obscura (see 4.7, Chapter 1 of the 1979 edition);

h) Removed the requirement for wooden planks (see Chapter 1 of the 1979 edition)

i) Added specimens (see Chapter 5);

j) Added test environment (see Chapter 6);

k) The test steps, calculation formulas and result expressions of the brushing method have been changed (see 7.1, Chapter 2 of the 1979 edition);

l) Changed the test steps and result presentation of the spray method (see 7.2, Chapter 3 of the 1979 edition);

m) Increased precision (see Chapter 8);

n) Added test report (see Chapter 9).

Introduction

Hiding power is one of the important construction properties of coating products. Coating products of the same quality, under the same construction conditions, have strong hiding ability Paint products with higher coverage can cover more area than paint products with weaker hiding power. GB/T 23981 aims to establish the covering power of coatings The determination method is intended to consist of two parts.

---Part 1: Determination of contrast ratio of white and light-colored paint. Applicable to contrast ratio of white or light-colored paint with tristimulus value Y greater than 25 Determination.

---Part 2: Black and white grid method. Suitable for measuring the hiding power of paints.

This time, GB/T 1726 is revised to GB/T 23981.2, mainly considering the black and white grid method and the determination method of contrast ratio of white and light-colored paint.

Compared with the other methods, the coating hiding performance reflected is similar, and it is more convenient to query and use as a series of standards. During revision, the equipment, equipment and materials were improved by improving the requirements, operating steps and calculation formulas, etc., making the technical content of the document easier to understand and operate, and can better promote the trade and technology of coating products. technology development.

Warning---The use of this document may involve hazardous materials, operations, and equipment. This document is not intended to address all safety aspects associated with the use of question. Users of this document are responsible for taking appropriate steps to ensure the safety and health of personnel and to identify any other The applicability of his restrictions.

1 Scope

This document describes a method for assessing hiding power by applying paint evenly to the surface of black and white checkered panels.

This document is applicable to the determination of the hiding power of paints.

2 Normative reference documents

The contents of the following documents constitute essential provisions of this document through normative references in the text. Among them, the dated quotations For undated referenced documents, only the version corresponding to that date applies to this document; for undated referenced documents, the latest version (including all amendments) applies to this document.

GB/T 1727 General preparation method of paint film

GB/T 3186 Sampling of paints, varnishes and raw materials for paints and varnishes

GB/T 9754 Determination of 20°, 60° and 85° specular gloss of paint and varnish films containing no metallic pigments

GB/T 20777 Inspection and preparation of paint and varnish samples

GB/T 23981.1-2019 Determination of hiding power of colored paints and varnishes Part 1: Determination of contrast ratio of white and light-colored paints

3 Terms and definitions

The following terms and definitions apply to this document.

4 Materials and instruments