Will the hot melt adhesive particles solidify too quickly and seep into the paper seam? Quickly improve the list of 5 adjustment parameters

Curing too fast and not seeping into the paper seam? First, check these 5 parameters

In book and magazine packaging,hot melt adhesive pelletsThe curing speed directly determines whether the adhesive can fully penetrate the spine paper seam. Curing too quickly=Insufficient penetration=Weakened bonding strength. The following 5 key parameters help you quickly locate the problem.

• 1. Is the glue temperature too lowFor every 10 ° C decrease in operating temperature, the opening time is shortened by about 3-5 seconds. Suggest a temperature of 170-180 ° C for the backing adhesive and 165-175 ° C for the side adhesive.
• 2. Does the opening time match the machine speedThe entire process of milling back, gluing, and cover pressing must be completed within the opening time. If the machine speed is 500 books/hour, the opening time should be at least 8 seconds or more.
• 3. Whether the milling depth meets the standardThe standard milling depth is 1.5-2.5mm, and if the depth is not enough, the adhesive cannot penetrate the paper layer. Even if the adhesive solidifies slowly, it will be useless.
• 4. Environmental temperature impactIn winter, when the temperature in the workshop is below 15 ° C, the paper absorbs the heat from the adhesive solution and accelerates the curing process. You can increase the glue temperature by 5-10 ° C or preheat the spine appropriately.
• 5. Is the rubber particle model selected incorrectlyQuick fix type (opening hours)<6秒）适合高速薄本，不适合厚本书刊。换用森莱热熔胶粒的标准开放时间型号即可。

Frequently Asked Questions (FAQ)

Q: Is the glue temperature already 180 ° C or is it curing too quickly? What should I do?

A: Continuing to heat up beyond 180 ° C will accelerate the aging of the adhesive (yellowing and brittleness), and is not recommended. The fundamental solution is to switch to a model with a longer opening time.

Q: Can adding glue make up for insufficient penetration?

A: I can’t. Excessive glue can lead to overflow and a thick adhesive layer, which affects the smoothness of the spine. The core is to allow the glue to fully penetrate during the opening time.

Q: How to determine if penetration is sufficient?

A: Tear open the spine section of the book, and the adhesive should penetrate more than 2/3 of the deepest milling groove. If only adhesive is applied on the surface, it indicates insufficient penetration.