The full name of polyurethane (PU) is polyurethane. It is a polymer compound. There are two types of polyurethanes: polyester and polyether. It can be made into polyurethane plastic (mainly foam), polyurethane fiber (called spandex in China), polyurethane rubber and elastomer. Application of polyurethane:
PU soft foam:
1. Cushion materials, such as seats, sofas, mattresses, etc., polyurethane soft foam is a kind of Very ideal cushion material, cushion material is also the application area with the largest amount of soft foam;
2. Sound-absorbing material, open-cell polyurethane soft foam has good sound absorption and shock absorption functions, and can be used as indoor sound insulation Materials;
3. Fabric composite materials, shoulder pads, cotton pads, toys, etc.
PU rigid foam:
1. Refrigeration and refrigeration equipment, such as refrigerators, freezers, cold storage, refrigerated trucks, etc., polyurethane rigid foam is the most ideal insulation material for refrigeration and refrigeration equipment;
2. Industrial equipment insulation, such as storage tanks, pipes, etc.;
3. Building materials. In Europe and the United States, polyurethane rigid foam for construction accounts for about 70% of the total consumption of rigid foam. It is more than double the amount of hard foam used in refrigerators and freezers; in China, the application of hard foam in the construction industry is not as common as in the West, so the development potential is very large.
PU semi-rigid foam:
1. Energy-absorbing foam, energy-absorbing foam has excellent shock absorption and cushioning properties, good compression load resistance and deformation recovery Its most typical application is to prepare automobile bumpers;
2. Self-skinned foams are used to prepare softening interior functional parts and interior trims such as automobile steering wheels, armrests, and headrests . Integral skin foam products usually adopt reaction injection molding (RIM) processing technology;
3. Microcellular elastomer, the most typical application of polyurethane microcellular elastomer is used in the shoe industry.
Characteristics and testing items of polyurethane materials:
1. Characteristics of polyurethane elastomers: wear resistance, wide hardness range, high strength, oil resistance, high bearing capacity, good Vibration absorption performance, low temperature resistance performance, radiation resistance and ozone resistance, mold resistance performance, biomedical performance Polyurethane coating materials are widely used in the textile and garment industry. At present, the main problems are poor moisture permeability, hardening at low temperatures, easy hydrolysis and aging, and are not suitable for long-term storage. Wait for the problem. The hemp stalk core has developed micropores, moisture absorption and moisture conduction, antibacterial, anti-ultraviolet, adsorption and reactivity, etc. The achievement completion unit used the natural material of the hemp stalk core with special functions to modify the defective polyurethane synthetic material.
2. Main testing items:
Apparent density, haze, yellowness, whiteness, swelling ratio, water content, acid value, melting point, hardness, impact strength, tensile strength Elongation, melt index, viscosity, mold shrinkage, melting temperature, etc.
Partial testing standards:
GBT19250-2003 polyurethane waterproof coating;
QBT1646-2007 polyurethane synthetic leather;
GBT10802-2006 general Soft polyether polyurethane foam;
GBT20219-2006 sprayed rigid polyurethane foam;
QBT2904-2007 self-skinned rigid polyurethane foam;
p> JC-T998-2006 Spray polyurethane rigid foam insulation material;
QCT704-2004 Test method for overall hardness of polyurethane foam coating of automobile steering wheel;
ISO8873-3-2007 Rigid foam plastics. Thermal insulation sprayed polyurethane foam plastics. Part 3: Test methods;
GJB1585-93 Test methods for physical properties of polyurethane rigid foam plastics.
