Cross cut test - Reliability Test

Date：2021-11-03 16:52:00Views：4013

The 100 grid test is used to draw a grid with a certain specification and size evenly, and evaluate the adhesion of the coating film to the substrate by evaluating the integrity of the coating film in the grid, which is expressed as "grade". It is mainly used to determine the adhesion of organic coatings by cross cutting method. It can be used not only in the laboratory, but also in the construction site under various conditions. Generally speaking, it is a tool for testing the adhesion of the test object after coating. According to the Japanese industrial standard (JIS), it is divided into 1 ~ 5 levels. The higher the level, the stricter the requirements. When the customer specification requires level 5, it means that there can be no falling off at all.

Reference standard ISO 2409:2013

This international standard specifies a test method to evaluate the resistance of the coating to separation from the substrate when the right angle lattice pattern is cut into the coating and penetrated into the substrate. Among other factors, the performance determined by this empirical test procedure depends on the adhesion of the coating to the previous coating or substrate. However, this procedure should not be considered as a method of measuring adhesion.

If adhesion needs to be measured, the method described in ISO 4624 [1] can be used

Note 1: Although this test is mainly used in the laboratory, it is also applicable to field tests.

The method described can be used as a pass / fail test or, where appropriate, as a six step classification test. When applied to a multi coating system, the resistance to separation between layers of the coating can be evaluated.

The test can be carried out on finished products and / or specially prepared samples.

Although this method is applicable to paints on hard (e.g. metal) and soft (e.g. wood and gypsum) substrates,

These different substrates require different test procedures.

This method is not applicable to coatings with a total thickness greater than 250 or for textured coatings.

Note 2 when this method is applied to a coating designed to provide a rough pattern surface, it will produce results that show too many changes

Baige test tool index

Cutter spacing: 1 + 0.01mm, 2 + 0.01mm, 3 + 0.01mm.

Tooth tip width: 0.05mm.

Cutter tooth spacing: 1mm / 2mm / 3mm

Paint film thickness: up to 60 μ M suitable for hard (such as metal and plastic) substrates with a spacing of 1mm

up to 60 μ M, 2 mm spacing for soft (e.g. wood and gypsum) substrate / 120um / 250 μ m

sixty-one μ m - 120 μ M 2mm spacing for soft and hard substrates;

one hundred and twenty-one μ m-250 μ M 3mm spacing for soft and hard substrates

Paint film over 250 μ M, the 100 grid test is not applicable.

sampling

Take a representative sample of the product to be tested in accordance with ISO 15528.

Inspect and prepare each sample for testing in accordance with ISO 1513

basal

Select one of the substrates described in ISO 1514.

The panel shall be flat without deformation. The dimensions shall allow for testing

It shall be carried out at three different positions, and the distance between each other and from the edge of the panel shall not be less than 5mm.

If the panel consists of relatively soft materials such as wood, the minimum thickness shall be 10 mm.

If the panel consists of hard material, the minimum thickness shall be 0.25 mm.

Note 1: rectangular panel, the size is about 150 mm × 100 mm has been found to be convenient.

Note 2: if the panel is made of wood, the direction and structure of the texture will affect the test, and an obvious particle will make the evaluation impossible.

5.2 preparation and coating

Prepare each test plate in accordance with ISO 1514 and coat it in accordance with the specified method

Product or system under test.

5.3 drying

Drying (or furnace) and aging (if applicable) each coated test plate under specific conditions at the specified time and temperature.

5.4 coating thickness

Determine the thickness of the dry coating in microns according to one of the procedures specified in ISO 2808. Measure at or as close as possible to the position where the transverse cut is to be made. The number of thickness measurements depends on the method used

working principle

With tools of certain specifications, the hundred grid knife cuts and penetrates the coating as a grid pattern. The patterns completed by grid drawing are classified according to six levels to evaluate the resistance of the coating to separation from the substrate. It is mainly applicable to the determination of adhesion of organic coatings by cross cutting method. It is not only suitable for the laboratory, but also for the construction site under various conditions.

Grade

ISO level: 0

The edge of the cut is completely smooth, and the edge of the lattice is free of any peeling.

ISO grade: 1

There are small flakes at the intersection of the cuts, and the actual damage in the cross cut area shall not exceed 5%.

ISO grade: 2

The edges and / or intersections of the cuts are peeled off, with an area of more than 5% but less than 15%.

ISO grade: 3

There is partial peeling or whole peeling along the edge of the cut, and / or part of the lattice is completely peeled off. The spalling area is more than 15%, but less than 35%.

ISO grade: 4

Large scale peeling off at the edge of the cut / or partial or total peeling off of some squares, with an area greater than 35% but not more than 65% of the cross cut area.

ISO grade: 5

Exceed the previous level

operation

1. The test piece must be prepared according to the provisions of ISO r1514 and ISO 2808.

2. Place the test piece on a flat plate with sufficient hardness.

3. Hold the handle of the scriber to make the multi edge cutting knife perpendicular to the plane of the test piece.

4. Cut with uniform pressure, stable and non vibrating technique and cutting speed of 20-50mm / s.

5. Rotate the test piece by 90 degrees and repeat the above operations on the cut to form a lattice pattern.

6. Brush the test piece 5 times backward and 5 times forward along the two diagonals of the grid pattern with a soft brush.

7. The test shall be completed at least at three different positions of the test piece. If the test results at three positions are different, the test shall be repeated at more than three positions, and all results shall be recorded at the same time.

8. If it is necessary to replace the multi edge cutting knife, loosen the two screws on the screwdriver body, replace the knife used, stick the blade to one side of the handle and tighten the screws.

matters needing attention

1. All cuts shall penetrate the coating, but not too deep into the substrate.

2. If the coating cannot penetrate the substrate due to its thickness, the test is invalid, but it shall be stated in the test report.

3. Under special circumstances or special requirements, it shall be measured with the tape method. The tape is generally 25mm wide translucent tape, and the back material is polyester film or acetate fiber. Stick the adhesive tape on the whole grid, and then tear it off at the minimum angle. The result can be obtained by taking the surface area of the paint film as an example.

4. The test shall be carried out at a temperature of 23 ± 2 ℃ and a relative humidity of 50 ± 5%.

Baige test standard

1. It is designed and manufactured according to iso2409-1992 standard.

2. Applicable to GB / t9286-98, BS 3900 E6 / ASTM d3359.