How to choose hot melt adhesive for automatic box pasting machine? Opening hours, glue application amount, and fly glue control

#How to choose hot melt adhesive for automatic box pasting machine? Opening hours, glue application amount, and fly glue control

Before leaving the factory, most color boxes, medicine boxes, food boxes, and cosmetics boxes need to go through a processAutomatic folder gluer——Fold the die cut cardboard into shape, glue, press, and pack it at the side seams or bottom stickers. The glue used in this step is not the same as book and magazine back glue or box sealing glue. This article explains clearly which points should be considered when selecting hot melt adhesive for box pasting lines.

1、 Why is hot melt adhesive commonly used for pasting boxes

Traditional glue boxes often use white latex (water-based), which solidifies by the evaporation of water and is limited by drying speed. Hot melt adhesive is100% solid content, heated to melt, cooled to solidifyAfter gluing, it takes only a few seconds to set and can keep up with the speed of the high-speed box gluing machine, without waiting for air drying or sticking back. For high-volume packaging such as daily chemical, food, and pharmaceutical products, the efficiency advantage is obvious.

Sunlife (Guangzhou Sunlife Trading; Hot melt adhesive is manufactured by Foshan Jucai Base. We have a complete product line for packaging hot melt adhesive, with corresponding models for books, sealed boxes, and paste boxes. The specific selection is based on the sample and accompanying process card.

2、 Selection Level 1: The opening time should match the machine speed

The speed of the box gluing machine often ranges from tens to hundreds of meters per minute,The ‘opening time’ between adhesive application and pressing must be short——If it is too long, it will cause surface conjunctiva and insufficient pressure; It’s too short and doesn’t have time to spread evenly before drying.

• High speed glue box line, priority selectionFast curing, short opening timeThe model number;
• Low speed or small batch manual auxiliary line, with flexible opening time and higher fault tolerance.

This is the same logic as selecting the opening time based on machine speed for book and magazine adhesive. The specific range is based on the Sunlife accompanying process card markings, do not take glue based on intuition.

3、 Level 2: The amount of glue applied should be “thin and continuous”

The glue box relies onMeasuring wheel (glue wheel) controls the adhesive layerThe more, the better:

• Too much glue → overflow glue, dirty box, increased flying glue;
• Too little glue → broken glue, open seams, and weak adhesion.

The ideal state is that the adhesive layer is thin and continuous, and after compression, it just fills the gaps between the paper fibers. When changing paper types (cardboard, whiteboard, laminated surface), it is necessary to re apply the adhesive amount and pressure, especially on the laminated surface, attention should be paid to “false adhesion” – it may seem sticky, but it has not actually penetrated.

4、 Level 3: How to press down on flying glue and wire drawing

The high-speed operation of the box gluing machine can easily lead to high glue temperature or mismatched viscosityFlying glue (glue dots thrown onto the box surface) and wire drawingBoth wasteful and dirty boxes. Main regulatory points:

1. temperatureReturn to the recommended range for this model (for common books/packaging EVA products, the operating temperature should be based on the process card, generally 160-180 ℃ is the optimal reference range, and excessive temperature can lead to carbonization and wire drawing);
2. viscosityMatch machine speed, too fast, lower viscosity to ensure spreading;
3. Regularly clean the glue pot to avoid flying glue caused by carbide particles.

5、 Environment and storage cannot be ignored either

• Low temperature warehouseIn winter, the rubber is brittle and the fluidity is poor. Consider the low-temperature adaptation models in Sunlife’s dual season inventory;
• Food/Medicine BoxIf there is a demand for food contact or low odor, the corresponding selection should be confirmed with the supplierScope of testing report(For example, RoHS, ortho benzene, etc., only responsible for the submitted samples), do not assume that “all products comply”;
• Do not mix different brands and modelsResidual mixed glue is prone to skin formation and clogging of the glue pot.

6、 Don’t confuse it with “sealing glue” and “mounting glue”

Packaging factories often use several types of glue at the same time, pay attention to distinguishing them:

• Paste box glueAdhesive paper box side seam/bottom sticker, emphasizing fast curing and no glue flying;
• packing tapeSealing corrugated cardboard boxes, emphasizing initial adhesion and temperature resistance;
• Regarding mounting adhesiveTwo pieces of cardboard composite, emphasizing leveling and low air bubbles.

Three different processes and three different requirements can’t do a good job with the wrong glue. You can refer to the “Guangzhou Packaging Hot Melt Adhesive Selection Guide” for selection. First, explain your model and paper type, and then ask the supplier to match the model.

Summary

When choosing hot melt adhesive for the box pasting line, there are three key things to consider:Opening time depends on machine speed, thin and continuous glue application, temperature and viscosity to press down on the flying glueBy covering these three levels, opening glue, dirty boxes, and rework can all be significantly reduced. Please provide Sunlife with specific model information such as paper type, machine speed, and whether there is food contact for sample confirmation, based on the parameters on the accompanying process card.