Color printed corrugated cardboard box sealing hot melt adhesive particle bonding strength test: 3 common misconceptions leading to distorted results

Misconception 1: Only performing room temperature peeling is considered qualified

Many packaging factories only conduct peel tests at room temperature of 25 ° C and pass if they feel they cannot be peeled off. In fact, the transportation of color printed corrugated cardboard boxes requires extreme conditions such as high temperature carriages (50 ° C+), cold storage (-18 ° C), and high humidity environments. Being qualified at room temperature does not necessarily mean being reliable under all operating conditions.

The correct approachAdd at least two testing points, high temperature of 50 ° C and low temperature of -10 ° C, to simulate real transportation conditions.

Misconception 2: Drop testing only checks whether the cardboard box is damaged or not

During the drop test, many people only check whether the cardboard box is cracked, ignoring whether the sealing glue line is displaced or detached. The cardboard box is intact but the glue line has been displaced, making it easy to unpack during subsequent transportation.

The correct approachAfter falling, measure the displacement of the adhesive line with a caliper. If it exceeds 2mm, it is considered unqualified; Simultaneously conduct a secondary drop test to verify the fatigue resistance of the adhesive wire.

Misconception 3: The larger the amount of glue applied, the stronger the adhesion

Increasing the amount of glue applied to corrugated cardboard boxes does not increase the bonding strength nonlinearly – the incremental returns decrease after exceeding 60g/m ², and excessive glue can penetrate the corrugated core paper, leading to a decrease in cardboard strength and ultimately reducing the overall compressive strength of the cardboard box.

The correct approachThe optimal range for glue application is between 40-55g/m ², and proper placement of glue points is more effective than simply adding glue. Sunlifehot melt adhesiveThe sealing special model can achieve the tearing strength of corrugated paper with a coating amount of 40g/m ². Guangzhou Sunlife Trading can provide standard test samples and testing method guidance.

Frequently Asked Questions

• Q: What is the difference in bonding strength between printed and plain corrugated paper boxes?
  A: Due to the influence of the ink layer, the adhesive strength of printed surfaces is usually 15-30% lower than that of plain surfaces, and high adhesion models should be selected.
• Q: What is the typical height for drop testing?
  A: According to ISTA standards, the drop height of 0-20kg cardboard boxes is 76cm, and the drop height of 20-30kg is 61cm, simulating the actual handling drop.