A large collection of common hot melt adhesive gluing methods

Hot melt adhesive is a kind of plastic adhesive. Its physical state changes with temperature within a certain temperature range, but its chemical properties remain unchanged. It is non-toxic and tasteless. It is an environmentally friendly chemical product; hot melt adhesive is used The hot-melt adhesive machine melts the hot-melt adhesive through heat, and the melted glue becomes a liquid, which is sent to the surface of the adhered object through the hot-melt adhesive hose and hot-melt glue gun of the hot-melt adhesive machine. The way the hot melt glue is applied determines the effect of the glue.

1. Roller gluing

The molten hot-melt adhesive is conveyed into a rotating rubber tank, and the upper rubber roller rotates in the rubber tank, and the molten hot-melt adhesive on the upper rubber roller is scraped evenly by the scraper, and the product contacts the rotating rubber roller to evenly apply glue. This gluing method is mainly used for fabric coating and compounding, sheet gluing, etc.

2. Foam coating

In some special applications, in order to obtain the function of cushioning or shock absorption while reducing the amount of glue used, a special foamable glue machine can be used to mechanically mix nitrogen into the molten hot-melt pressure-sensitive adhesive, An air-filled hot melt pressure sensitive adhesive is formed. Then apply the hot-melt pressure-sensitive adhesive that has been mechanically foamed on the workpiece through the nozzle. The foam coating process has been widely used in the combination of auto parts to replace traditional rubber gaskets.

3. Spiral spray glue

This is the most common way of spraying glue. The hot-melt pressure-sensitive adhesive is ejected into a regular spiral glue thread from the spray sheet with fine orifices in the nozzle by the external air pressure. Applying glue in this way can drastically reduce the amount of glue used per unit area. Most of the structural adhesives for diapers and sanitary napkins are glued by spiral spraying.

4. Scratch coating of flat die head

This is a more common scraping method. After the molten hot melt pressure sensitive adhesive passes through the heated throat, it is evenly distributed in the guide channel in the die, and then extruded from the lip of the die that can preset the thickness and width of the film. Most industrial hot-melt pressure-sensitive adhesive tapes and labels are applied using a die coating process.

5. Spot gluing

Spot gluing is a fairly economical and fast simple process when two substrates only need to be bonded in part. Spot gluing is commonly used in the bonding of folding cartons or cardboard.

6. Strip gluing

Similar to dot gluing, this process can be used when two substrates only need to be combined in strips. Common applications are the edges of plastic boxes, such as PET curtain boxes, wine bottle boxes and cosmetic boxes.

7. Curtain spray glue

When the object to be coated needs to obtain a fully coated glue area due to insufficient heat resistance (such as PE film) or uneven surface of the workpiece, the non-contact (suspension) curtain spray glue can provide a similar contact die Scratch effect.

8. Fibrous spray glue

Its glue spraying process is basically quite similar to the spiral glue spraying method, except that the shape of the glue sprayed out is irregular, and the amount of glue sprayed per unit area is lower than that of the spiral glue spraying method. The most common application market is disposable sanitary materials, such as disposable mattresses, surgical gowns, caps, shoe covers, etc.