TAPPI T-569 Standard Test for Internal Bond Strength (Scott Type)

EUROLAB, with its state-of-the-art accredited laboratories and expert team, offers precise and rapid testing services within the scope of the TAPPI T-569 test. This method describes a test that measures the energy required to rapidly delaminate a sheet-type sample.

Rupture in the "Z" direction is initiated by the impact of a pendulum that has both a controlled mass and a controlled speed that exceeds 6000 times the speed of tensile strength and other dead weight testing devices. The geometry of the apparatus causes the tensile stress to be rotational in nature, with negligible shear stress on the sample. The method is suitable for both single- and multi-ply paper and board, including coated sheets and sheets laminated with synthetic polymer films.

Limitations include materials that allow significant migration of tape adhesive to the sample with potential tape-to-tape bonding or materials that may become structurally damaged or collapse during the press cycle. To determine the feasibility of the test method, it is important to visually inspect both sides of a set of at least 10 delaminated samples. The ability of the device to disrupt a sample within the measuring range is an insufficient criterion.

The test is a measurement of strain energy per unit sample area, proportional to the area under the stress-strain curve. Strength measurements made by this method are not related to tensile strength tests (ZDT) in the "Z" direction, which measure maximum (peak) stress at a slow, constant rate of elongation or deadweight failure.

A sandwich of double-sided tape, paper sample, and double-sided tape is pressed between a flat metal anvil and an aluminum plate. A pendulum strikes the upper inner surface of the platen, causing the paper sample to rotate and split in the thin "Z" direction. The energy absorbed in breaking the sample is calculated by measuring the peak of the overswing of the pendulum.

Strength equation parameters include:

• Potential energy of the ratchet pendulum;
• The peak of the oscillation;
• Energy required to accelerate the bare sample angle away from the pendulum;
• Friction losses;
• Internal vibration losses pendulum.

EUROLAB assists manufacturers with TAPPI T-569 test compliance. Our test experts, with their professional working mission and principles, provide you, our manufacturers and suppliers, the best service and controlled testing process in our laboratories. Thanks to these services, businesses receive more effective, high-performance and quality testing services and provide safe, fast and uninterrupted service to their customers.