1. Adhesive pressure molding
This method is the most common method for the recycling of waste polychlorinated esters. The main point is: first smash the waste polyurethane rigid foam into a thin piece. A polyurethane adhesive or the like is applied, and a high-temperature gas such as water vapor is directly introduced to melt or dissolve the polyurethane adhesive, and then the powdered waste polyurethane is bonded, and then pressure-cured into a foam of a certain shape. There are two main types of rigid polyurethane foam waste: one is polyurethane rigid foam represented by refrigerator and cold storage, and contains no other hybrids; the other is waste rigid polyurethane foam produced by adiabatic sandwich panels. A multi-fiber or metal facestock is a blend. There are some differences in their recycling processes.
The waste insulation sandwich panel polyurethane foam is about 70% polyurethane foam, 25% fiber (such as roof insulation panel), 3% aluminum foil and 2% glass fiber, which is difficult to screen. When it is used as a filler directly in a polyether polyol, the viscosity of the polyol increases sharply, and when it is only 4%, it becomes a paste and cannot be used. The use of a gluing process is a viable process. After crushing the rigid polyurethane foam sandwich waste material into about 12.7 mm pieces, add about 6% polyphenyl polymethyl polyisocyanate (PMDl) adhesive and mix in a rotary mixer (immediately quantitative adhesive) The spray was continuously sprayed onto the broken foam sheet) and then molded into a sheet having a thickness of about 12.7 mm at about 176 ° C by about 6 MIN. The internal bond strength, flexural strength, hardness and thread strength of the board are superior to wood particle board, and the water resistance and dimensional stability far exceed all wood boards.
In the case of equal density, the rigidity of the rigid polyurethane foam board is worse than that of the wood particle board. It is possible to add inexpensive wood fiber, recycle waste paper pieces, and wood chips to increase the rigidity and meet the standard requirements. Example: Poplar shards and 3% PMDl adhesive are mixed to form a core. The outer layer is made of rigid polyurethane foam shards and 6% PMDI adhesive in one step, which can meet the requirements of the standard. The molded plate has a smooth surface and good moisture resistance, and is an ideal plate for outdoor indoor furniture. There is a good potential market. The biggest drawback of this method is that the performance of the regenerated PMI foam product is degraded. It is only suitable for low-grade parts such as furniture and automobile lining. The application is narrow, the process is cumbersome, the labor is large, and the economic value is not high.
2. Used as a filler
Waste rigid polyurethane foam powder, commonly used as a filler for polyurethane building materials, such as the roof insulation layer, mixing cement, sand, water and waste rigid polyurethane foam powder on the bottom layer of the roof surface, the thermal insulation properties of the material Excellent, light weight (almost 1/2 of the density of the cement layer without the addition of waste rigid polyurethane foam), the material can be nailed.
3. Extrusion molding
Extrusion is the transformation of the molecular chain into a medium-length chain by thermodynamics, transforming the PU material into a soft plastic material, which is suitable for high strength and high hardness. However, plastic parts that do not require high elongation at break. For the soft microporous PMI foam waste, it can be pulverized into a powder, blended into a thermoplastic polyurethane, granulated in an extrusion molding machine, and an article such as a sole is manufactured by an injection molding method.
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