What hot melt adhesive particles are used for sealing multi-layer paper bags? 6 parameter selection list and bag type comparison

Direct answer: It is recommended to choose multi-layer paper bags with high initial adhesion, medium to short opening time, and good folding resistance for sealingHot melt adhesive granulesThe softening point is above 90 ℃, commonly known as EVA high viscosity or APAO type. The difficulty of multi-layer paper bags lies in the multiple layers of bag openings, the paper often having coatings or moisture-proof films, and the adhesive needs to quickly bite and withstand repeated bending during transportation.

Application background: Multi layer paper bags are not ordinary cardboard boxes

Chemical raw materials, grain feed, and building materials powder are commonly packaged in two to four layer kraft paper bags, with a single bag weight of 25-50 kilograms. Once the sealing of such packaging fails, the loss is not only the bag, but also the spilled materials and on-site cleaning costs. The biggest difference between it and cardboard box sealing is that the force is continuous, the bag body deforms with the flow of materials, and the sealing needs to be repeatedly bent during transportation.

Selection checklist: six parameters that must be confirmed

Key points for using glue for different bag types

• Ordinary kraft paper multi-layer bagGood paper absorption, conventional high viscosity EVA type is sufficient, pay attention to controlling the amount of glue applied to avoid rapid penetration.
• Composite bag with PE inner membraneThe inner membrane surface energy is low, and APAO type with better adhesion to polyolefin needs to be selected.
• Coating moisture-proof bagThe coating blocks penetration and relies mainly on interface bonding. It is recommended to increase the initial bonding and extend the compression appropriately.
• Valve bagThe sealing area is small, stress is concentrated, and the adhesive layer needs to be continuous and uninterrupted.

Three things that are easily overlooked on site

• Bag dust: Dust flying during powder filling falls on the sealing surface, which is the most common cause of failure. It should be blown before sealing.
• Compression pressure: The multi-layer paper bag has a large rebound, and when the compression pressure is insufficient, the adhesive layer does not touch the inner layer at all.
• Stacking timing: The newly sealed bags should be immediately stacked high, and the glue should be compressed and deformed before fully curing. It is recommended to leave a cooling time.

Sunlife Hot Melt Adhesive Solution

Guangzhou Sunlife Trading provides Sunlife hot melt adhesive for multi-layer paper bag customers, with a focus on high initial adhesion and folding resistance balance: it can bite the rebounding bag opening within two to three seconds without slipping due to creep during long-term stacking. Specific models will be recommended based on bag type, filling weight, and storage environment during supply, and samples can be sent to the customer’s site for on-site verification.

Frequently Asked Questions

Can ordinary sealing granules be used for sealing multi-layer paper bags?

Light load and short distance are acceptable, but for heavy bags and long-term stacking, it is recommended to use specialized models with higher softening points and better folding resistance. Ordinary sealing glue is prone to slip during summer stacking.

What does it mean if the seal is opened but the paper is not broken?

The explanation is interface damage, usually related to dust, coating or insufficient compression. First investigate these three items, and then consider replacing the adhesive.