GB/T 34445-2017 "Determination of Thermal Adhesive Properties of Thermoplastic and Its Composite Materials Hot Cover" is an important testing standard in China for the thermal adhesive properties of flexible thermoplastic and its composite materials hot cover，This standard provides a scientifically unified method for evaluating thermal adhesion performance in fields such as packaging and medical devices, especially suitable for scenarios where filling or processing needs to be carried out immediately after heat sealing.

Applicable materials: The standard is applicable to flexible thermoplastic plastics and their composite materials (such as PE, PP, PET composite films, etc.), and the test object is the bonding performance of the hot sealing surface within a specific time interval from the end of heat sealing to the end of cooling.

Thermal adhesion: The peeling force per unit width of the heat sealed area before cooling to ambient temperature.

Thermal adhesion curve: The curve of thermal adhesion force changing with heat sealing temperature, used to analyze the thermal adhesion characteristics of materials.

Failure modes: including 7 types such as delamination, cohesive failure, and composite film delamination, which need to be recorded in detail during testing.

test instrument

Puchuang TechnologyHBT-01 Hot Adhesive Tensile Tester：Equipped with dual heat sealing knives, the temperature control accuracy is ± 0.5 ℃, the pressure sensor accuracy is ± 5%, and it supports at least two fixture separation speeds of 25mm/s and 200mm/s (33.3mm/s is required for compatibility with method A/B).

Sample cutting device: Prepare samples with widths of 15mm, 25mm, or other suitable widths, ensuring smooth edges.

Environmental conditioning chamber: According to GB/T 2918-1998, pre treat the sample for at least 4 hours under the conditions of 23 ± 2 ℃ and 50 ± 10% humidity.

Test Principle

By simulating the actual heat sealing process, peel testing is conducted immediately after heat sealing to measure the adhesive strength of the heat sealed area in a high-temperature softened state. The testing process requires strict control of time intervals to ensure that the data reflects the instantaneous thermal adhesion properties of the material.

test method

Method A (fixed delay time):

The delay time is not adjustable. Record the thermal adhesive force at different cooling time points and draw the cooling curve, which is suitable for analyzing the thermal adhesive attenuation characteristics of materials.

Method B (adjustable delay time):

Set a specific delay time (such as 100ms) to measure the maximum thermal adhesion during the fixture separation process, suitable for optimizing heat sealing parameters.

Testing process:

State adjustment: Preprocess the sample according to the standard environment.

Parameter setting: Enter the heat sealing temperature, time, pressure, and delay time (method B).

Heat sealing and testing: Immediately perform peel testing after heat sealing, and automatically record the force value and curve.

Failure mode recording: Observe and classify the types of failure of the specimen (such as delamination, cohesive failure, etc.).