ISO 15184-2012 pdf download.Paints and varnishes – Determination of film hardness by pencil test.
ISO 15184 specifies a method for determining the film hardness by pushing pencils of known hardness over the film.
The test can be performed on a single coating of a paint, varnish or related product, or on the upper layer of a multi-coat system.
This rapid test has not been found to be useful in comparing the pencil hardness of different coatings. It is more useful in providing relative ratings for a series of coated panels exhibiting significant differences in pencil hardness.
The method is applicable only to smooth surfaces.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
ISO 1513, Paints and varnishes — Examination and preparation of test samples
ISO 1514, Paints and varnishes — Standard panels for testing
ISO 2808, Paints and varnishes — Determination of film thickness
ISO 15528, Paints, varnishes and raw materials for paints and varnishes — Sampling
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1 pencil hardness
resistance of the surface of a paint film to marking, or the formation of some other defect, as a result of the action of a pencil, with a lead of specified dimensions, shape and hardness, which is pushed across the surface
4 Principle
A pencil lead with a defined geometry is pushed over the paint surface at an angle of 450, exerting a force of 7,5 N on the surface. The hardness of the pencil lead is increased in steps until the surface of the coating is marked by visible defects. The test result is the highest hardness at which no marking occurs.
5 Apparatus
5.1 Test instrument, consisting of a metal block ftted with two wheels, one on each side, as shown in Figure 1. The wheels shall be made in such a way that they do not scratch the paint surface during testing. In the middle of the metal block, there is a cylindrical hole, inclined at an angle of (45土1)°, for the pencil.With the help of a clamp, pencils can be fixed in the instrument so that they are always in the same position. Mounted on the top of the instrument is a level which is used to ensure that the test is carried out with the instrument horizontal.
The instrument shall be designed so that, with the instrument in the horizontal position, the tip of the pencil exerts a force of (7,5土0,1) N on the paint surface.
Other types of test instrument may also be used, provided they give similar relative rating results.ISO 15184 pdf download.