With the requirements of China's automobile industry for weight reduction, noise and shock reduction, low emissions, low VOC, low odor and so on, automotive filter glue also has some new characteristics and development directions. Hot melt adhesive, because of its environmental protection and non-toxicity, fast curing, low odor, low VOC, wide bonding surface characteristics, is the development direction of adhesives for the filter industry. Below, we will make some examples of the application of hot melt adhesives in automotive filters.
1. Filter element origami bonding
The glue machine has a stable supply, sufficient melting, and keeps the glue at a specific temperature, stable viscosity, uniform fluidity, and ensures that the glue line is uniform and bubble-free. Glue melting machine: glue box temperature 150 degrees, hose temperature 140 degrees, nozzle temperature 130 degrees; After applying the glue, put the material into the drying oven, put it at 90 degrees for 24 hours, and see the changes of the adhesive paper, which can not be displaced, deformed.
2. Strengthen the adhesive line of the back spine
In order to strengthen the tooth-shaped filter element, several glue lines are placed on the filter element longitudinally to connect the tooth-shaped filter paper to form a solid whole. Commonly used PA hot melt adhesive, the glue is required to have a certain hardness, so that the filter is firm, but also has a certain degree of flexibility, even at a lower temperature, the glue line can not be brittle and broken. Different host manufacturers have different requirements for high and low temperature resistance.
3. Bonding seams
The filter paper is not ended and glued together, the bonding of the seam between the filter paper and the filter paper, usually with EVA hot melt adhesive, PO hot melt adhesive, PA hot melt adhesive, the filter paper seam of the air filter is commonly used EVA or PO hot melt adhesive, and the filter element seam in the oil filter is now mostly bonded with PA polyurethane hot melt adhesive, and it is also common to connect and seal with a metal clip. PA adhesive has very good high temperature resistance and media resistance. Most of the hot melt adhesive forms are rod-shaped, and the glue is melted with a hot melt glue gun and manually coated on the interface filter paper to close the seams.
4. Bonding of end covers
The bonding between metal end caps or plastic end caps and filter elements usually uses two-component PU adhesive, and there are many hot melt adhesives, which require good fluidity, bonding strength to meet requirements, and certain high temperature resistance and low temperature performance. PA hot melt adhesive for fuel / engine oil filtration, high temperature resistance reaches 180 ~ 190 degrees
5. Air conditioning filter frame bonding
The air conditioning filter frame seal is bonded, after the edge banding strip passes through the roller, the tip of the hot melter is evenly scraped, and then the edge banding strip is manually pasted around the filter element to complete the bonding sealing. Most of the edge banding adhesives of air conditioning filters are EVA hot melt adhesives, which require good fluidity, high bonding strength and excellent low temperature resistance. There are also some manufacturers who use manual hot melt glue guns to melt hot melt glue sticks, apply the glue to the edge banding strip, and then stick it to the filter element.
