The difference between polyurethane and polyurea, the main uses of polyurea.

Polyurea is a category of polyurethane.

Polyurea mainly reacts with the terminal amine group and NCO to form urea bonds, while usually polyurethane mainly reacts with NCO with -OH, and of course includes the former. In terms of reaction rate, the former is almost instantaneous, while the latter is slower, and generally requires catalyst participation.

Compared with ordinary polyurethane products, polyurea has good anti-corrosion performance, wear resistance and good rigidity, and is often used in large-scale projects in China.

1. Polyurethane is the full name of polyurethane, which is a general term for macromolecular compounds containing duplicate urethane groups on the main chain. It is made by the addition of organic diisocyanates or polyisocyanates with dihydroxyl or polyhydroxy compounds.

2. Polyurea is an elastomer substance formed by the reaction of isocyanate components and amino compound components. It is divided into pure polyurea and semi-polyurea, their properties are different, and the most basic characteristics of polyurea are anti-corrosion, waterproof, wear-resistant, etc.

You will know this at once, the reaction between isocyanic acid and amino group is urea, under the condition of 50C, urea is generated, and above 110C, diurea and urea are generated, but it is only a reaction in polyurethane. Polyurethane is a big concept.

Polyurethane. Polyurethane material is currently the best performance insulation material in the world. A class of polymers whose backbone contains —NHCOO—repetitive structural units.

Abbreviated as PU. It is formed by polymerization of isocyanates (monomers) and hydroxyl compounds. Due to the strong polar urethane group, insoluble in non-polar groups, it has good oil resistance, toughness, wear resistance, aging resistance and adhesion.

Different raw materials can be used to adapt to a wide range of temperatures.

materials. These include elastomers, thermoplastic resins, and thermoset resins. It is not resistant to hydrolysis at high temperatures, nor is it resistant to alkaline media.

Commonly used monomers such as toluene diisocyanate, methylene diphenyl diisocyanate, etc. There are 3 types of polyols: simple polyols (ethylene glycol, glycerol, etc.).

polyester oligomers containing terminal hydroxyl groups are used to prepare polyester-type polyurethanes; Polyether oligomers containing terminal hydroxyl groups are used to prepare polyether-type polyurethanes. The polymerization method varies depending on the nature of the material. In the synthesis of elastomers, low molecular weight diols are first prepared, and then reacted with excess aromatic or aliphatic isocyanates to form prepolymers with isocyanate (-NCO) as the end group, and then expanded with polyols to obtain thermoplastic elastomers; If the chain is expanded with dibasic amines and further cross-linked, a cast elastomer is obtained.

The prepolymer is expanded with hydrazine or dibasic amine to obtain elastic fiber; The prepolymer with a large amount of isocyanate is mixed with a catalyst and a blowing agent to directly obtain rigid foam. For example, by mixing monomer, polyether, water, catalyst, etc., flexible foam can be obtained by one-step reaction. The monomer reacts with the polyol in the solution to obtain the coating; The adhesive is mixed with polyisocyanate monomer and low molecular weight polyester or polyether and reacted during use.

Polyurethane elastomers are used in rollers, conveyor belts, hoses, automotive parts, shoe soles, synthetic leather, wires and cables, and medical artificial organs. Flexible foam is used in vehicles and living rooms.

The padding of the garment.

Rigid foam is used as thermal insulation.

Acoustic absorption, packaging, insulation, and low-foaming synthetic wood, coatings are used for high-end vehicles, furniture, wood and metal protection, leakage prevention materials for pools, dams and buildings, and fabric coatings. Adhesives have good adhesion to metals, glass, ceramics, leather, fibers, etc. In addition, polyurethane can be made into emulsions, magnetic materials, etc.

Polyurea is SPUA

A class of compounds formed by the reaction of isocyanate components with amino compounds. Isocyanate components can be monomers, polymers, derivatives of isocyanates, prepolymers and semi-prepolymers.

Polyurea is a polyamide of carbonated carbon, which is comparable to polyester that is explored. The urea group is polar and can form more hydrogen bonds, so the melting point of polyurea is higher than that of the corresponding polyamide, and the toughness is also large, which is suitable for textile fibers. Polyurea can be polymerized from diamine with diisocyanate or urea.

Polynonylurea is a representative polyurea polymer. It is prepared by condensation of nonanediamine and urea.

Its properties are similar to those of polyamides (e.g. Nalen 6).

It can be melt spinning, the melting temperature is 230 235, the density is small (gram cm3), it has good heat resistance, dyeing and corrosion resistance, fiber tensile strength Newton, elongation 23%, suitable for the manufacture of fishing nets and knitwear.

Polyurea is an elastomer substance formed by the reaction of isocyanate components with amino components. In amino compounds, there are hydroxyl components and catalysts, which are called mixed polyureas.

Uses: waterproof and anti-corrosion of underground concrete structures, drainage pipes, etc.; anti-corrosion of steel beams and steel pipes, steel plates, simple silos and storage tanks; parking lots, floors for factories, warehouses and shopping malls; waterproofing and corrosion protection of marine structures, bridge piers and swimming pools; road ramp reinforcement and underground cavern waterproof and anti-corrosion coatings; Foam sculpture protective.

Features: fast curing, can be sprayed on any curved surface, inclined plane and vertical surface, no sagging; Excellent physical properties, superior impact resistance, wear resistance, cold resistance, heat resistance, water resistance and aging resistance; Easy to use, color adjustable, spraying thickness is unlimited; It has good crack bridging performance; Good adhesion to all kinds of substrates; Solvent-free, high solids, safe and environmentally friendly.

Jiangsu Kedi environmental protection.

Polyurea is divided into manual polyurea and sprayed polyurea, and manual polyurea is divided into single-component polyurea and two-component aspartal polyurea. The physical strength of all three is very good. Foshan Wanhua Technology produces all three.

Commonly said polyurea is sprayed polyurea, about ten seconds of curing, the need for special professional equipment for spraying construction, one-component polyurea and two-component asparagus polyurea can be roller coating or spraying with ordinary equipment. At present, polyurea is mainly used for waterproof and anti-corrosion projects. It is characterized by long service life, high strength and weather resistance.

Polyurea is made by spraying semi-prepolymers, terminal amino polyethers, amine chain extenders and other raw materials on site. It is extremely hydrophobic, insensitive to ambient humidity, and can even be sprayed on water (or ice) to form a film, and can be applied normally under extremely harsh environmental conditions, and its performance is particularly outstanding.

The emergence of polyurea has completely broken the traditional concept of anti-corrosion and protection, and set a higher standard for the material protection industry. Polyurea coatings are flexible, rigid and colorful, dense, continuous, and seamless, completely insulating from the penetration of moisture and oxygen in the air, and have unrivalled anti-corrosion and protective properties. At the same time, it has a variety of functions such as wear resistance, waterproof, impact resistance, fatigue resistance, aging resistance, high temperature resistance, and nuclear radiation resistance.

SPUA technology is a new type of "all-purpose" coating technology, which is known as the greatest discovery in the field of paint and coating technology at the end of the twentieth century. It combines new technologies, new materials and new processes, and is a revolutionary leap forward in traditional construction technology. It has been applied in developed countries such as North America for more than ten years, and the market demand is very strong.

In terms of molecular structure, the catalytic systems of polyurea waterproof coatings and polyurethane waterproof coatings are different, which means that catalysts must be added when using polyurethane waterproof coatings to be used normally, and the addition of catalysts increases the reactivity of polyurethane and water at the same time, which also causes a series of negative effects such as instability and aging of the system. This catalyst will exist between the layers of the material for a long time after the reaction, and with the induction of sunlight, oxygen, water or other corrosive media, the molecular chain will be broken and the material performance will be reduced. The polyurea waterproof coating does not need to be sprayed with catalysts, the molecular structure is more stable, and the aging resistance is much higher than that of polyurethane waterproof coating.

Urea's polyurethane pants are elastomers obtained by the reaction of oligomeric glycols (or triols), diisocyanates and small molecule polyols (chain extenders and crosslinkers), and the raw materials do not contain amine-based substances. This elastomer can generally be prepared by the one-step method and the prepolymer method (two-step method).

Firstly, the prepolymer is obtained by the reaction of oligomeric diol (or triol) with diisocyanate, and then the prepolymer is solidified by reaction with aromatic diamine chain extender. The elastomer molecular chain contains both carbamate and urea group, and when the elastomer is carefully distinguished, the elastomer belongs to polyurethane urea, but polyurethane urea is generally classified as polyurethane.

Polyurethane (PU), the full name of polyurethane forme, is a polymer compound. It was produced in 1937 by Otto Bayer and others. There are two types of polyurethane: polyester type and polyether type.

They can be made into polyurethane plastics (mainly foam), polyurethane fibers (known as spandex in China), polyurethane rubber and elastomers.