How to determine the low-temperature brittleness temperature of hot melt adhesive particles? The matter of a batch of churches returning goods from the north

Return event process

A packaging factory in Guangzhou has been supplying sealed boxes to a daily chemical brand in the north for a long timehot melt adhesive pelletsThe southern region has been warm throughout the year without any problems. A batch of goods was sent to the Harbin warehouse in winter, but the customer reported that the carton seal could be opened as soon as it was broken, and the entire batch was returned. After investigation, it was found that the EVA rubber particles used by the factory had a low-temperature brittleness temperature of about -5 ° C, while the temperature in the Harbin warehouse reached -20 ° C at night, and the adhesive layer had completely become brittle and would crack upon light touch.

How to determine the low-temperature brittleness temperature?

The Brittle Point is the critical temperature at which adhesive particles transition from a flexible state to a brittle state. Below this temperature, the adhesive layer loses its elasticity and bonding fails. Viewing method:

• 1. Refer to the Technical Data Sheet (TDS)Regular manufacturers label TDS with “Low Temperature Flexibility” or “Brittle Temperature”, read directly
• 2. Calculation without annotationsEVA based adhesive particle brittleness temperature ≈ softening point -40~50 ° C; PO based ≈ softening point -60 ° C
• 3. Actual testing is the most reliableTake adhesive particles to bond the sample strip and place it in a low-temperature chamber. Perform a bending test every 5 ° C drop, and crack to reach the brittle point

Selection and Prevention

The minimum temperature of the target usage environment must be at least 10 ° C higher than the brittleness temperature of the rubber particles, leaving a safety margin. Outdoor transportation in northern winter must choose models with a brittleness temperature of ≤ -25 ° C. Sunlife hot melt adhesive, a specialized model for the north, has a brittleness temperature of -30 ° C. Guangzhou Sunlife Trading recommends that customers select products based on extreme low temperatures along the transportation route, rather than warehouse temperature.

Frequently Asked Questions

• Q: Do you occasionally need to change the glue for one or two orders of southern products sent to the north?
  A: If the transportation will experience temperatures below -10 ° C, it must be replaced. The loss of a single return is much greater than the price difference of changing the glue.
• Q: Is low-temperature brittleness the same as becoming brittle in winter?
  A: Yes, it is. Brittle in winter is a sign that the ambient temperature is lower than the brittleness temperature, which can be solved by switching to a lower brittleness temperature model.