GB/T 30789.6-2015Paints and varnishes -- Evaluation of degradation of coatings -- Designation of quantity and size of defects, and of intensity of uniform changes in appearance -- Part 6: Assessment of degree of chalking by tape method (English PDF)

Foreword

GB/T 30789 "Paints and varnish coating aging rating number and size of the defect and the identity of the extent of uniform changes in appearance." Divided into nine sections.

--- Part 1. General and identification systems;

--- Part 2. Evaluation of blistering levels;

--- Part 3. Evaluation of rust grade;

--- Part 4. Evaluation cracking grade;

--- Part 5. Evaluation of flaking grade;

--- Part 6. Assessment of degree of chalking tape method;

--- Part 7. Method for Evaluation of velvet cloth chalking rating;

--- Part 8. scribe or other artificial defect assessment and corrosion peeling peripheral level;

--- Part 9. Evaluation of filiform corrosion level.

This section GB/T Part of 630,789.

This section drafted in accordance with GB/T 1.1-2009 given rules.

This section uses the translation method identical with ISO 4628-6:2011 "number and size of paints and varnishes Evaluation of degradation of coatings defects as well as the appearance of a uniform degree of change identification - Part 6. Assessment of degree of chalking tape method. " this part is proposed by the China Petroleum and Chemical Industry Association.

This part of the National Standardization Technical Committee and the pigment coating (SAC/TC5) centralized.

This section drafted by. CNOOC Changzhou Paint Chemical Research Institute Co., Ltd., Guangzhou standard laboratory equipment Geda Products Co., Ltd., Guangzhou State Institute of Materials Co., Ltd., Sino New Materials Co., Ltd., Shenzhen Hirota Decoration Group Co., Ltd.

1 Scope

GB/T 30789 in this section provides a powder coating paint assess the degree of reference images. This section also specifies the assessment powder Method level. When using this method, it is important to carefully distinguish between genuine aging degradation products and contaminants, especially when slight chalking.

2 Terms and definitions

The following terms and definitions apply to this document.

Chalking

Because of its surface coating of one or more binder degradation and decomposition of pigment, while showing a loose powder adhesion phenomena.

Principle 3

With sticky tape from the test under the powder coating, facing the reference background (black or white, regardless of the election which aim to give the most obvious reference Photo) Check the powder adhered to the adhesive tape on the assessment of degree of chalking according to rating table.

4 Materials

4.1 self-adhesive transparent tape, a width of at least 15mm.

Colorless transparent soft tape is suitable, the tape will affect the quality assessment results. Type tape parties shall agree and Test report noted.

4.2 Background, black or white non-reflective surface, such as paper cards, or can not afford velvet fuzz velvet cloth.

5 Program

5.1 at room temperature so that the coating surface is dry, and then tested.

Dried coating surface put a piece of tape (see 4.1), applying steady pressure with a finger back and forth pressed. The length of the tape at least 40mm.

A direction perpendicular to the surface of the tear tape, put it in the appropriate colors can be displayed on the sharp contrast of the background (see 4.2), adhesive tape Contact with the substrate surface. Evaluation of light-colored coating on a black background, a dark coat on a white background assessment.

Under steady lighting immediately sticky powder tape each picture in Figure 1 compares the reference standard (see 5.5) to assess the degree of chalking.

Background of the higher visibility of the lower degree of chalking. Lighting conditions noted in the test report.

5.2 degree of chalking can also use the appropriate optical instruments, by comparing the powder stained tape and unused tape measure transmittance quantified