Polyurethane
Polyurethane (PU) is a synthetic resin widely recognized for its versatility and strength. As a polyurethane plastic material, it combines the flexibility of rubber with the toughness of plastic. This makes it an ideal solution for a wide range of industrial applications, from coatings to foams. The adaptability of polyurethane stems from its chemical structure, which allows it to be molded into a wide variety of products.
Physical and chemical properties
Physical properties
Physical properties: The physical properties of polyurethane vary with its type. Generally speaking, the density of polyurethane is between 1.2 and 1.3 g/cm³, and it has the characteristics of high density, high strength, high toughness, and high wear resistance. Polyurethane has the appearance of a yellow or brownish-yellow viscous liquid, is insoluble in water, but can be dissolved in organic solvents such as styrene and xylene. Its melting point, relative density, solubility and other physical and chemical properties vary depending on the specific type.
Chemical properties
Physical properties: The physical properties of polyurethane vary with its type. Generally speaking, the density of polyurethane is between 1.2 and 1.3 g/cm³, and it has the characteristics of high density, high strength, high toughness, and high wear resistance. Polyurethane has the appearance of a yellow or brownish-yellow viscous liquid, is insoluble in water, but can be dissolved in organic solvents such as styrene and xylene. Its melting point, relative density, solubility and other physical and chemical properties vary depending on the specific type.
Product classification
Polyurethane foam plastics
Polyurethane foam plastics are divided into two types: hard foam and soft foam. They have excellent elasticity, elongation, compression strength and softness, as well as good chemical stability. In addition, polyurethane foam plastics have excellent processability, adhesion, thermal insulation and other properties, and are excellent performance buffer materials
Polyurethane elastomer
Since its structure has two segments, soft and hard, the polyurethane elastomer can be given high strength, good toughness, wear resistance, oil resistance and other excellent properties through the design of the molecular chain. Polyurethane, known as “wear-resistant rubber”, has both the high elasticity of rubber and the rigidity of plastic
Polyurethane fiber plastic
Polyurethane fiber plastic has high tensile strength and toughness, making it a preferred material in many applications. It has good wear resistance and excellent oil resistance, making it suitable for applications that require wear resistance, such as ropes, sports shoe materials, etc., and can maintain stable performance in environments where some oils and chemicals exist. Polyurethane fibers show high elasticity and resilience, making them widely used in applications with high elasticity requirements, such as elastic fabrics, springs, etc.
Product application areas
Furniture industry
In the furniture industry, imitation wood materials are one of the main application directions of polyurethane rigid foam. Imitation wood materials are light in weight and have the same density and strength as wood. Using this material to make furniture will not only prevent cracks after molding, but also reduce the cost of production and manufacturing.
Construction industry
Polyurethane rigid foam is the preferred material for building insulation. It has a simple structure, long product life, high construction efficiency, high fire resistance and low overall cost. With the continuous implementation of China’s energy-saving and environmental protection policies, the construction industry will face more stringent tests during the “13th Five-Year Plan” period, and polyurethane rigid foam will be widely used in the field of building insulation.
Shoemaking and leathermaking industry
China is the world’s largest exporter and production base of footwear products, and its footwear production accounts for 60% of the global total. Polyurethane (PU) material is a type of polyurethane. In addition, slurry is mainly used to manufacture artificial leather, synthetic leather and other related products.
Transportation industry
Polyurethane is also present in the transportation industry, which mainly includes soft, hard and semi-hard foam plastics, as well as polyurethane elastomers, polyurethane glue, polyurethane sealant and polyurethane coatings.
Home appliance industry
Refrigerators and freezers mainly use polyurethane rigid foam as the insulation material of home appliances. Under the same volume conditions, this material can effectively increase the internal volume of refrigerators and freezers and reduce the total amount of external shell materials. It can not only reduce production costs, but also reduce the weight of refrigerators and improve thermal insulation performance.
Sports industry
Polyurethane paving materials are widely used in the construction of plastic tracks, indoor basketball courts, and volleyball courts in stadiums and public sports venues.
Polyurethane recycling methods
Polyurethane is a commonly used plastic material. Due to its excellent physical properties and chemical stability, it is widely used in packaging, construction, electronics, automobiles and other industries.
There are mainly the following methods for recycling polyurethane:
A. Mechanical recycling method: Mechanically crush polyurethane waste into small particles, and then crush, screen and process them to finally obtain polyurethane particles that meet the requirements.
B. Chemical recycling method: Mix polyurethane waste with appropriate solvents (such as NMP, DMF, etc.), heat and stir under appropriate conditions to dissolve polyurethane in the solvent, and then recover polyurethane and obtain particles through evaporation, concentration and other steps.
C. Physical recycling method: Use physical methods such as modification and modification to make polyurethane waste suitable for reprocessing and use, such as preparing polyurethane foam.
