What is polyurethane? Main applications in those areas?

Polyurethane is known as Polyurethane Foam (PU) and is a general term for macromolecular compounds containing repeating urethane groups in the main chain. It is formed by the addition of an organic diisocyanate or a polyisocyanate to a dihydroxy or polyhydroxy compound. Commonly used monomers such as toluene diisocyanate, diphenylmethane diisocyanate and the like. Polyols are classified into three categories: simple polyols (ethylene glycol, glycerol, etc.); polyester oligomers containing terminal hydroxyl groups, used to prepare polyester polyurethanes; polyether oligomers containing terminal hydroxyl groups, used A polyether polyurethane is prepared. The polymerization method varies with the nature of the material.

The polyurethane macromolecule may contain, in addition to the carbamate, a group such as an ether, an ester, a urea, a biuret or an allophanate. Depending on the raw materials used, there are products of different nature, generally polyester and polyether. Can be used in the manufacture of plastics, rubber, fiber, rigid and flexible foams, adhesives and coatings.

Polyurethane is an emerging organic polymer material. It is known as the “fifth largest plastic” and is widely used in construction, automotive, light industry, textile, petrochemical, metallurgy, electronics, national defense, medical, for its excellent performance. Machinery and many other fields.

Polyurethane characteristics

1. Polyurethane contains strong polar urethane groups, and the ratio of NCO/OH in the formulation can be adjusted to obtain different products of thermosetting polyurethane and thermoplastic polyurethane.

2. A resin containing a repeating -HNCO-O- group in the main chain of the polyurethane, usually formed by stepwise addition polymerization of a polyisocyanate, a polyol polymer or an aromatic diamine.

3. The molecular structure of polyurethane can be divided into two types: linear type and body type. The bulk structure may exhibit hard, soft or intermediate properties due to different crosslink density.

4. Polyurethane has high strength, high wear resistance and solvent resistance.

Polyurethane application

Polyurethane rigid foam

Rigid polyurethane foam, referred to as polyurethane rigid foam, is a rigid foam material which has the functions of waterproofing, heat insulation and the like formed by mixing a component material and a B component material. Polyurethane rigid foam is mostly closed-cell structure, with excellent thermal insulation effect, light weight, high specific strength, convenient construction, etc. It also has the characteristics of sound insulation, shockproof, electric insulation, heat resistance, cold resistance and solvent resistance. Insulation materials such as refrigerator insulation, refrigerator insulation, cold storage, refrigerated trucks, buildings, storage tanks and pipeline insulation materials, a small amount for non-insulated applications, such as imitation wood, packaging materials.

Polyurethane soft foam

Soft polyurethane foam, referred to as polyurethane soft foam, is a flexible polyurethane foam with certain elasticity, which is the largest polyurethane product in polyurethane products. Mainly used as mats for furniture mats, mattresses, vehicle seat cushions, etc., as well as soft foam for industrial and civil use as filter materials, sound insulation materials, shockproof materials, decorative materials, packaging materials and insulation materials. According to the degree of softness and hardness, that is, the load resistance performance, polyurethane soft foam can be divided into ordinary soft foam, super soft foam, high load soft foam, high rebound soft foam and the like.

Imitation wood

High density (density 300~700kg/m3) polyurethane rigid foam or glass fiber reinforced rigid foam is a structural PU foam, also known as imitation wood, with high strength, good toughness, dense and tough skin, simple molding process, production High efficiency, higher strength than natural wood, lower density than natural wood, can be used as a high-grade product instead of wood.

car

Polyurethane materials are widely used in the automotive industry due to their excellent properties: low VOC, lightweight, high performance BaSF-Elastoflex E for the roof and interior components of the BMW i3 electric car. Mercedes-Benz also uses BaSF polyurethane foam. The new Mercedes-Benz smart fortwo uses Elastoflex E polyurethane foam in a honeycomb sandwich roof. The weight of the new Mercedes-Benz smart fortwo is about 30% lighter than the average canopy, but still maintains good strength and bending stiffness.

Polyurethane summary:

The above is the material of polyurethane, the use of polyurethane and other issues are introduced here, I hope to help everyone.