Polyurethane coating agent is the main type of development today. Its advantages are: soft and elastic coating; good coating strength, can be used for very thin coating; porous coating, moisture permeability and aeration; wear resistance, Moisture resistant and dry cleaning resistant. The disadvantages are: high cost; poor weather resistance; hydrolysis in water, heat and alkali.
The TPU coating agent is classified into a polyester type polyurethane, a polyether type polyurethane, an aromatic isocyanate type polyurethane, and an aliphatic isocyanate type polyurethane. According to the medium used in the use, it is divided into solvent and water.
The polymers containing repeating structural units of the -NHCOO- group on the macromolecular backbone are collectively referred to as polyurethanes, abbreviated as polyurethane (PU). It is prepared by reacting an organic polyisocyanate with a polyether or polyester polyol. Polyurethane plastics commonly found in the form of soft and hard foams.
Rigid Polyether Polyurethane Foams Physical and Chemical Properties
Density: 0.04 to 0.06 g/cm3 (25 degrees Celsius), tensile strength: 0.147 MPa, flexural strength: 0.196 MPa, thermal conductivity: 0.035 W/(mK). The biggest feature of this product is that it can synthesize the products with the required properties by changing the specifications, varieties and formula of raw materials according to the specific application requirements. The product is light in weight (adjustable density), high in specific strength, superior in insulation and sound insulation, good in electrical performance, good in processability, resistant to chemicals, low in water absorption, and added to flame retardant to produce self-extinguishing products. . Compared with the polyether type hard foam of the same density, the material has higher tensile strength and better oil resistance, solvent resistance and oxidation resistance, but the viscosity of the polyester is large and the operation is difficult.
The main purpose
Mainly used for cold storage, cold tanks, pipelines and other departments for insulation and thermal insulation materials, high-rise buildings, aviation, automotive and other departments to do structural materials to maintain insulation and light weight. The ultra-low density hard foam can be used as a packing material for shockproof packaging materials and hull interlayers.
Physicochemical properties of Flexible Polyether Polyurethane Foams
Density: 0.03 to 0.07 g/cm3, tensile strength: 8.83 to 117 kPa, elongation (%): 150 to 300. Bending strength: 0.196 MPa, thermal conductivity: 0.034 to 0.041 W / (mK). Melting point (°C): 170 to 190.
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