In order to test the paint film of oil-based paint and grease-based paint, that is, to test the paint film with low tensile strength, it is suitable to use the HNNJIK instrument designed by CH Xie Lie Briannikov.
The HNNJIK instrument (Fig. 139) consists of a wooden base to which a metal frame is fixed. There is a fixed clip on the upper part of the rack, and a second movable clip is installed 50 mm below the clip. There is also a water collector and an automatic recording pen with a volume of 600 milliliters on this clip. A timing mechanism with a rotating cylinder is also installed on the shelf. An automatic recording pen mounted on a movable clip touches a drum on which millimeter graph paper is placed. Two buckets stacked one above the other are arranged on the rear wall of the base. The vat above was filled with water and the well was covered with a ground plug. Weld a pipe under the barrel to connect to the keg below. Install a hydraulic lock door in the lower phase so the level of water in the bucket remains constant forever. As the water in the small bucket flows out one after another, the water in the large bucket is filled into the small bucket. The small bucket is connected with the water collector by a pipe with an automatic valve, and the device can be operated by using the automatic valve. After the automatic valve is opened, the timing machine starts, and the water evenly flows into the collector, thus elongating the paint film. At this time, the paint film breaks after stretching to a certain extent (related instruments: tensile Tester ). After the paint film breaks, the movable clip with the collector just falls down, and the well stops the water supply and the rotation of the drum. The amount of water (in grams) that flows from the collector into the graduated cylinder indicates the tensile strength of the clear paint film. The resulting graphs represent the progression of film elongation and breakage. ()
In order to obtain reliable results, the determination should not be less than three wells to take the average value. Many tests of oil-based and ester-based paint films by Lazarev and Glydenstein have shown the good performance of the HNNJIK instrument.
