What is Hot Tack Testing?

Introduction of Hot Tack Test

The hot tack test aims to measure the ability of a material to form a secure seal under dynamic conditions, specifically while the seal is still hot.

The hot tack test is a method used to evaluate the heat sealability of flexible packaging materials. This method is described in detail in ASTM F1921. The hot tack test is particularly important in industries where heat sealing is employed to create seals in packaging, such as food, pharmaceuticals, and consumer goods.

Application of Hot Tack Test in Packaging Industry

Quality Assurance

Packaging manufacturers use the hot tack test to ensure the quality and consistency of their materials. By evaluating the hot tack strength, manufacturers can identify any variations in material properties and take corrective actions to maintain product quality.

• Example: A packaging company regularly performs hot tack tests on samples from different production batches to ensure consistency in sealing performance. If any deviations are detected, adjustments can be made to the manufacturing process to maintain product quality.

Optimization of Sealing Parameters

The hot tack test helps in optimizing the sealing parameters such as temperature, pressure, and dwell time. By conducting tests under various conditions, packaging manufacturers can determine the ideal parameters for achieving strong and reliable seals.

• Example: A food packaging manufacturer conducts hot tack tests at different temperature and pressure settings to determine the optimal parameters for sealing their packaging materials. By identifying the ideal conditions, they can minimize seal failures and improve efficiency.

Development of New Packaging Solutions

The hot tack test is instrumental in the development and innovation of new packaging solutions. Packaging engineers can use the test results to design and optimize novel materials and sealing techniques that meet the evolving needs of the industry.

• Example: A packaging research and development team uses hot tack testing to evaluate the performance of a newly developed biodegradable film. By analyzing the hot tack strength and other sealing properties, they refine the material formulation to meet industry requirements.

Regulatory Compliance

Regulatory bodies often require packaging materials to meet certain standards for safety and performance. The hot tack test provides quantitative data that can be used to demonstrate compliance with regulatory requirements and industry standards.

• Example: A packaging supplier performs hot tack tests according to ASTM or ISO standards to demonstrate compliance with regulatory requirements. By providing documented test results, they assure their customers that the packaging materials meet the necessary safety and performance standards.

FAQ about Hot Tack Test

• Q: What is purpose of hot tack strength?
  A: Hot tack refers to the ability of a heat-sealed package to maintain its seal strength immediately after sealing, while the seal is still hot. The primary purpose of hot tack is to ensure that the package remains securely sealed during the initial stages of cooling, when the seal is most vulnerable to premature failure due to handling or transportation stresses. By measuring hot tack properties, packaging professionals can assess the seal’s ability to resist opening forces and maintain integrity until it cools down completely.
• Q: What is difference between hot tack and heat seal?
  A: Hot Tack: Hot tack specifically refers to the strength of the seal immediately after it’s formed while the sealing surfaces are still hot and molten. It indicates the ability of the material to resist premature opening during the initial cooling phase.
  Heat sealing: Heat sealing is the process of using heat and pressure to join two packaging materials together to create a bond. It’s a broader term that encompasses the entire sealing process, from the application of heat and pressure to the cooling and solidification of the seal.
• Q: How is hot tack strength measured?
  A: Hot tack is typically measured using specialized equipment such as a hot tack tester. The process involves sealing two materials together under controlled temperature and pressure conditions. Once the seal is formed, a force is applied to one side of the seal to simulate the stress it would experience during handling or transportation. The hot tack strength is then determined by measuring the force required to peel the sealed materials apart while the seal is still hot.

Recommended testing instruments

The HTT-02 Hot Tack Tester from Cell Instruments is a cutting-edge instrument designed for measuring the hot tack and seal strength of flexible packaging materials. Its advanced features include precise temperature control, adjustable sealing pressure, and customizable test parameters, ensuring accurate and reliable results. With its user-friendly interface and robust construction, the HTT-02 simplify the testing process, making it an indispensable tool for packaging manufacturers and researchers.

References: ASTM International ASTM F2029