PU, a polymer compound, refers to polyurethane. It was produced by Otto Bayer and other people in 1937. Polyurethane can be divided into 2 categories: polyether type and polyester type. They can be made into polyurethane fibers (spandex in China), polyurethane plastics (mainly foam), elastomers and polyurethane rubber.
Soft polyurethane features a thermoplastic linear structure. It has better chemical resistance, stability, resilience and mechanical properties, less compression deformation than PVC foam materials. It is also characterized by sound insulation, good heat insulation, anti-virus performance and anti-vibration. So it is used as material for sound insulation, package and filter. Rigid polyurethane plastic is light, excellent in heat insulation and sound insulation, good chemical resistance, easy to process, good electrical properties and low water absorption. It is usually used as a kind of structural material for construction, aviation industry, automobile and thermal insulation. The performance of polyurethane elastomer is between rubber and plastic with good oil resistance, low temperature resistance, abrasion resistance, aging resistance, high hardness and excellent elasticity. It is mainly used in the shoe manufacturing and medical industry. Polyurethane can also be used to make coatings, adhesives, synthetic leather, etc.
Polyurethane emerged in the 1930s. Over the course of technological development for nearly eighty years, this material has been widely applied in home furnishing, daily necessities, construction, transportation and home appliances.
PU product classification
Polyurethane products are mainly divided into several types as followed: foam plastics, elastomers, fibers, fiber plastics, coatings, leather shoe resins, adhesives and sealants, and foam plastics account for the largest proportion.
Polyurethane foam is divided into two types: hard foam and soft foam. It has excellent elasticity, compressive strength, elongation and flexibility, as well as good chemical stability. In addition, polyurethane foam also boasts excellent processability, adhesiveness and heat insulation, so it is a cushioning material with excellent performance.
The polyurethane materials have been produced throughout North America. It is reported that the overall average annual growth rate of polyurethane foam market in North America is expected to reach about 6%. It is estimated that by 2020, the growth areas are mainly in the residential and industrial market that need spraying polyurethane foam, as well as in military filed. In addition, polyurethane will also be used in the medical industry to offer a timely and effective treatment for patients.
Polyurethane elastomer has two-segment structure: soft one and hard one, so we can endow the material with excellent properties like high strength, good toughness, good wear resistance and oil resistance through adjusting the molecular chain, so the polyurethane called “wear-resistant rubber” can combine the high elasticity of rubber and the rigidity of plastic.
Polyurethane fiber plastic
The continuous fall of spandex price leads to a decline of profits in industry. The oversupply caused by continuous release of new smart production capacity also severely dealt a blow to spandex market.
In terms of the development and application of polyurethane coatings, two-component polyurethane coatings is the most dominant one whose application in the fields of wood furniture coating and other fields have been continuously expanded. In addition, one-component polyurethane coatings still enjoy strong application favors in automotive processing, basement waterproofing and other fields. The main material of this type of coating is polyurethane and it is very applicable in the production of various color paints and varnishes. Taken the biuret as the curing agent, the newly developed acrylic polyurethane paint is very applicable and reliable in automotive repair paint. Especially for light cars, large passenger cars and vans, the coating function in vehicle processing is very admirable, and its market prospect is considerable. Many new types of polyurethane coatings developed on the basis of acrylic polyurethane coatings can also be used in other manufacturing and processing fields to meet the requirements for processing quality of processed objects such as household appliances and trains.
In addition, special polyurethane coatings that can be applied to machine tool coating, floor coating, aerospace equipment surface coating and other fields are in the phase of accelerated development and research. Relevant reports has summarized and analyzed the current classification, characteristics and application of polyurethane coatings.