How to reduce the curling rate to zero in a picture book factory when using hot melt adhesive particles to paste the hardcover book ring lining

A high-end decoration factory that produces annual reports and commemorative brochures for enterprises, with long-term use of ring lining (connecting the inner pages of the book core and cover)Bent edges, bubblesCustomer complaints continue. I changed several types of glue but couldn’t cure it, so I finally solved it by “choosing the right glue+modifying the process”. The story is as follows.

Root cause of curled edges

Ring lining isPaper to paper+partial to hard sealing shellComposite bonding, originally using universal book adhesive, had insufficient initial bonding, uneven coating, incomplete air release during compression, and shrinkage and foaming after drying. The temperature and humidity in the plus workshop fluctuate greatly, and the opening time of the adhesive is not sufficient.

How to change

• Change the glueSunlife hot melt adhesive gave aHigh initial adhesion, low shrinkage fine decoration ring lining special granulesThe melting point is about 88 ℃.
• Change coating: Altered by rollersNarrow seam scraping and coatingThe adhesive layer is 0.2mm uniform to prevent uneven thickness.
• Change the compression fitAlign within 4 seconds after gluing,Press flat for 8 secondsExhaust and let a heavy object sit for 30 minutes.
• Control the environmentThe ring lining process maintains a constant temperature of 23 ℃ and humidity of 50% to reduce colloidal fluctuations.

Result

experience

Fine decoration ring liningIt’s not that the more expensive the glue, the better, it’s about matchingLow shrinkage+high initial adhesion+evenly coated three piece set. Guangzhou Sunlife Trading has written this parameter into the customer’s process card, which can also be reproduced by changing personnel.

Frequently Asked Questions

Q1: Can ordinary white latex be used for ring lining?
Yes, but it works slowly and is easy to pass through. Mass production is not as stable as hot melt adhesive granules.

Q2: Is the problem of more bubbles caused by glue or paper?
Most of them have uneven coating and no exhaust, so we need to change the pressing process first and then check the adhesive.