In order to perform satisfactorily, coatings must adhere to the substrates on which they are applied. In practice, three different test procedures are used to assess the resistance of paints and coatings to separation from substrates:
The method may be used for a quick pass/fail test. When applied to a multi-coat system, assessment of the resistance to separation of individual layers of thecoating from each other may be made.
This test method covers the determination of the adhesion of organic coatings such aspaint, varnish, and lacquer when applied to smooth, flat(planar)panel surface.It has been found useful in providing relative ratings for a series of coated panels exhibiting significant difference in adhesion.
The materials under test are applied at uniform thickness to flat panels, usually sheet metal of uniform surface texture. After drying, the adhesion is determined by pushing the panels beneath a rounded stylus or loop that is loaded with increasing amount of weight until the coating is removed from the substrate surface.
Adhesion of asingle coating or a multi-coat system of paint, varnish or related products is assessed by measuring the minimum tensile stress necessary to detach or rupture the coating in a direction perpendicular to the substrate. This method maximizes tensile stress as compared to the shear stress applied by other methods such as scratch adhesion and results may not be comparable. The test is performed by securing a loading fixture (dolly) perpendicular to the surface of the coating with an adhesive. After the adhesive is cured, a testing apparatus is attached to the loading fixture and aligned to apply tension perpendicular to the testsurface. The force applied is gradually increased and monitored until either a plug of coating material is detached, or a specified value is reached.
Digital pull off adhesion tester is a portable, hand-operated instrument which is used to measure the force required to pull a specified test diameter of coating away from its substrate using hydraulic pressure. The pressure is displayed on a digital LCD and represents the coating’s strength of adhesion to the substrate.
It evaluates the adhesion (pull-offstrength) of a coating by determining the greatest tensile pull-off force that it can bear before detaching. Breaking points, demonstrated by fractured surfaces,occur along the weakest plane within the system consisting of dolly, adhesive,coating layers and substrate.
Coating or a multi-coat system of paint is applied/distributed to substrate uniformly witha certain thickness.
After coating has been dried or cured, adhere dolly to surface of coating directly with special adhesive.
After the adhesive is cured, use digital pull-off adhesion tester to attach the loading fixture and aligned to apply tension perpendicular to the test surface. Tester pull off the dolly at a speed of 1MPa/s by hydraulic pump, and measures the force required to pull a specified test diameter of coating away from its substrate using hydraulic pressure, this force is shown through the LCD oftester.
Main Performance Of Instrument
Portable design with built-in rechargeable lithium battery, no external power supply, suitable for field and laboratory use.
Equipped with micro-usb interface, the device is similar to a U disk after being connected to the computer. The stored experimental data can be directly copied. There is no need to install any software.
Raw material complies with GB/T 5210, ASTM D4541/D7234, ISO 4624/16276-1 and other standards;
Real-time clock built in the machine, all saved data have corresponding experiment date and time, etc.Convenient for users to collect and manage experimental data;
The sizes of the latched spindles, which are available in Shanghai, are 10,14,20 and 50mm for products with different bonding strength, extending the function and resolution of the instrument.
Before each instrument leaves the factory, it is calibrated through NIST traceable pressure sensor. The precision is + / - 1% of the full range, and the calibration certificate is attached.
Internal latching data are stored, including maximum latching force, latching rate, testing time and the size of the latching spindle.
The pull rate indicated that it was easier for the operator to observe and adjust the pull rate in accordance with the international standard test method;
Click the button to select the drawing unit size, change the measuring unit or store the reading;
The instrument automatically calculates the drawing force according to the drawing unit size without changing the table.
The pullode unit USES cheap, fine aluminum spindles that meet international standards.
Sato aluminum's automatic alignment mid-drawing unit ensures that the tensile force is uniform when tested on smooth or uneven surfaces and prevents unilateral drawing.
Pressure sensors for advanced industrial applications ensure continuity of precision;
Liquid crystal, MPa or psi two units;
① ISO 4624 《Paints and varnishes-Pull-offtest for adhesion》
② ASTM D 4541 《StandardTest Method for Pull-Off Strength of Coatings Using Portable Adhesion Testers》
③ ASTM D7234 《Standard Test Method for Pull-OffAdhesion Strength of Coatings on Concrete Using Portable Pull-Off Adhesion Testers》
④ GB/T 5210 《Adhesion test of color and varnish pulling method》
Main Technical Parameters
■ Dolly Size：20mm（Standard）；10mm、14mm、50mm（Optional）
■ Accuracy：±1% Full scale
■ Max. Pull-off Pressure：Φ10mm dolly →0-80 MPa；Φ14mm dolly→0-40 MPa；
Φ20mm dolly→0-20 MPa；Φ50mm dolly→0-3.5 MPa；
■ Power：Built-in rechargeable lithium battery, and standard configuration charging adapter.
■ Adhesion Tester Size：360mm×75mm×115mm（L x W x H）
■ Adhesion Tester Weight：3KG