1. Distinguish by mold temperature
1)Thermal foaming:
After the casting is completed, the mold is placed in an oven at 220-250℃ (not lower than 180℃), and after the reaction is completed, it is taken out and demolded.
Advantages: low foam density, good heat aging performance, no need for separate openings. The mold cost is low.
Disadvantages: high energy consumption. The vent hole is easy to produce “mushroom head”, resulting in a lot of waste of chemical materials. Later on-site cleaning and equipment maintenance are more troublesome.
2)Cold foaming
It is generally designed as a multi-station turntable production line. The mold is generally heated to 45-70℃ by a mold temperature machine, and then demolded after the foaming reaction is completed by pouring the PU material. After demoulding, the product needs to use a foam breaker to help open the hole. Advantages: Low energy consumption, clean equipment and easy maintenance Disadvantages: The equipment is more complicated and the equipment cost is high. Foam thermalization performance is average.
2. Distinguish by surface adsorption
1)Naked foam:
Named contrary to the concept of adsorption and foaming, the fabric will not be pre-placed in the mold, and the surface of the foamed product is the PU layer. Noodles are all assembled after processing. Passenger cars mostly use this foaming process.
2)Adsorption foaming
Before pouring, first place the fabric in the mold cavity, make it completely fit by suction and adsorption, and then pour the PU material. After foaming, the surface layer of the molded PU product is tightly attached to the fabric. Construction machinery seats are more likely to use this foaming process.
3. Distinguish by hardness
1)Single hardness foam:
It is the simplest foaming, single formula, single pouring, no other auxiliary means, and the foam products presented have only a single hardness.
2)Double hardness foam
Double-hardness foam is the selling point of many luxury cars. The ride area is softer, and the support areas on both sides are harder, which can provide more comfort. The way to achieve this is to use the seating area and the two sides of the area to pour separately, and to achieve dual-hardness or multi-hardness distinction of the product by placing the mold at the angle, adding a material trough between the two wings and the seating area, and adding inserts on both sides of the foam. . This foaming process can also achieve three hardnesses, but generally not more. In the industry, it is also called double-density foaming, which is actually a slip of the tongue. The purpose of the process is to obtain different hardness, not density. And sometimes one density can make two different hardnesses. Manufacturers who master this foaming process generally need to be equipped with technical personnel who are skilled in adjusting the combination materials, because they need to master the changes and adjustments of multiple formulas.
Post time: Oct-17-2022