Production of polyurethaneFoam caulking Agent‘s factory produces a large amount of leftover materials, mold flash, and waste products every year. Polyurethane elastomers also have waste products, and waste in various application fields of polyurethane For example, old polyurethane foam and elastomers in scrapped cars also need to be recycled.
The vast majority of polyurethane materials are thermosetting, such as soft Rigid, rigid and semi-rigid polyurethane foams, as well as reaction injection molding (RIM) polyurethane elastomers used in the manufacture of automotive parts, etc. They cannot be melted and granulated like thermoplastic polyurethane and other thermoplastics, and mixed into new materials in small amounts for use. Other methods must be used.
Landfill method is a relatively helpless method to deal with waste. This method involves occupying land and incurring expenses. Since polyurethane is a nitrogen-containing polymer, if it is incinerated to recover heat energy, the combustion conditions must be strictly controlled and a system for absorbing toxic gases must be in place to reduce the pollution of toxic gases to the environment. Recycling and reusing waste plastics not only reduces environmental pollution, but also reduces the production cost of new products, which has good social and economic benefits.
The recycling of waste polyurethane materials can be divided intoPhysical Methodand Chemical methods, the following will befor polyurethane Waste material recycling technologymake a brief introduction.
1. Physical recycling method of polyurethane
1 . Bonding molding
This method is to crush the polyurethane foam into pieces of several centimeters through a crusher, spray reactive polyurethane adhesive, mix evenly, and then heat and press to form. The adhesive used is generally polyurethane foam composition or polyphenyl polymethylene polyisocyanate (
Phenol decomposition method— —Japan crushes waste polyurethane soft foam and mixes it with phenol. It is heated under acidic conditions to break the urethane bond, combine with the hydroxyl group of phenol, and then react with formaldehyde to make phenolic resin. Add Hexamethylenetetraminecuring it can produce strength and Phenolic resin products with good toughness and excellent heat resistance. Pyrolysis——Polyurethane soft foam can be decomposed at high temperature under aerobic or anaerobic conditions to obtain oily substances, and polyols can be obtained through separation.
Three, Thermal energy recovery and landfill treatment of polyurethane
1. Direct combustion
Recovering energy from polyurethane waste is a more environmentally friendly and economically valuable technology. The American Polyurethane Recycling Council is conducting an experiment in which 20% of waste polyurethane flexible foam is added to solid waste incinerators. The results show that the remaining ash and emissions are still within the prescribed environmental requirements. The heat energy released after adding the waste foam greatly saves the consumption of fossil fuels. In Europe, countries such as Sweden, Switzerland, Germany and Denmark are also experimenting with technology that uses the energy recovered during the incineration of polyurethane waste to provide electricity and heating.
can be PU foam is ground into powder alone or together with other waste plastics, and is burned in the furnace instead of fine carbon powder to recover heat energy. Finely powdering polyurethane fertilizer improves combustion efficiency.
2. Pyrolysis into Fuel
In the absence of oxygen, high temperature, high pressure and catalysts, flexible polyurethane foams and elastomers can undergo thermal decomposition to obtain gas and oil products. The thermal decomposition oil obtained contains some polyols and can be used as raw material after purification, but is generally used as fuel oil. This method is suitable for recycling mixed waste with other plastics. However, decomposition of nitrogen-containing polymers such as polyurethane foam may degrade the catalyst. This method has not yet reached a practical level.
Since polyurethane is a nitrogen-containing polymer, no matter which All combustion energy recovery methods must adopt the best combustion conditions to Reduce the generation of nitrogen oxides and amines. Burners need to be equipped with appropriate exhaust gas treatment devices.
3. Landfill disposal and biodegradable polyurethane
Currently, a considerable amount of polyurethane foam waste is disposed of in landfills. Some foams cannot be recycled, such as polyurethane foam used in seedbeds. Like other plastics, if the material is always stable in the natural environment, over time, more and more will put pressure on the environment. In order to make the landfilled polyurethane waste decompose under natural conditions after use, people have begun to develop Biodegradable polyurethane Resin. For example, biodegradable compounds containing sugars, cellulose, lignin or polycaprolactone are introduced into the polyurethane molecule.
Title of this article: Waste from the production of polyurethane foam caulking How to deal with it
Source of this article: http://www.wellgo.com.cn/newb/information_2549.shtml
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There is currently a considerable amount of polyurethane Foam waste is disposed of in landfills. Some foams cannot be recycled, such as polyurethane foam used in seedbeds. Like other plastics, if the material is always stable in the natural environment, over time, more and more will put pressure on the environment. In order to make the landfilled polyurethane waste decompose under natural conditions after use, people have begun to develop Biodegradable polyurethane Resin. For example, biodegradable compounds containing sugars, cellulose, lignin or polycaprolactone are introduced into the polyurethane molecule.
Title of this article: Waste from the production of polyurethane foam caulking How to deal with it
Source of this article: http://www.wellgo.com.cn/newb/information_2549.shtml
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