A two-component polyurethane is a polymer that is made by mixing the two ingredients. The first are isocyanate compounds, while the second can be compounds of the hydroxyl group. The elements interact, as a result of which a polymer with a polyurethane structure is formed.
Varieties of polyurethane
To obtain the polymer, it will be necessary to mix the hardener and the base in certain proportions. Two-component polyurethane can be represented by a cold and hot type of polymerization. The last version of the material requires exposure to elevated temperature, while the first polymerizes at natural temperature.
Key Features
The described materials, which are used for molds, have high strength characteristics, they are resistant to aggressive environments and harmful effects, as well as elevated temperatures. All these features expand the scope of use of polyurethane. It is suitable for the production of:
- paints;
- adhesive compositions;
- sealants;
- varnishes.
After mixing the components, the composition gains excellent fluidity, which makes it possible to produce parts from it by casting technology. As an example, we can distinguish bushings for mechanisms. The article deals with a two-component injection molded polyurethane. Material properties are determined by the starting components. In this case, the composition of the isocyanate hardener and the base are important.
Extra features
Material properties may vary depending on the addition of various substances, for example, fillers and dyes. Some polyurethanes replace rubber, because they are highly elastic. You can find polyurethanes that are able to restore their original shape during mechanical damage, this makes them especially valuable in the industry.
Overview of Uses
Two-component polyurethane is widely used today. Used material for the manufacture of jewelry, various mechanisms and casting gears. The operational properties of the parts obtained are quite high. This allows you to use the material even in difficult conditions. As a result, it is possible to obtain viscous, solid and chemically resistant parts. The latter may include:
- gears;
- shafts;
- pulleys;
- wheels
- rollers;
- timing belts;
- sealing elements;
- various protective coatings;
- couplings;
- pipelines;
- bearing parts;
- bushings.
Parts are ready to serve high quality and long, because they are resistant to wear and have high strength. Liquid elastic two-component polyurethane forms the basis of wheels for carts and loaders. As a result, it is possible to obtain products that are much stronger than rubber ones. They are ready to work even with tread damage.
The material forms the basis of the supporting and guide rollers, which are operated in conjunction with belt and conveyor conveyors. Elements are ready to serve much longer in comparison with rubber transmission belts, tracks and tracks.
The material is used for shock absorbers and sealing elements, because it is characterized by higher resistance to wear and durability. That is why rubber parts have recently been increasingly replaced by polyurethane. Elasticity at the same time remains at the same level. Two-component injection molding polyurethane has found application in the production of pipelines, which are characterized by chemical resistance and strength. Elements are solid. In addition, with the help of material, it is possible to protect pipelines not only from the inside, but also from the outside.
Additional Usage Reviews
According to consumers, two-component polyurethane is used in the manufacture of adhesives and paint products. The mixture after polymerization is resistant to external negative influences, holds firmly and is ready to serve for a long time. Liquid polyurethane is especially often used in the manufacture of molds that are made using casting technology. Subsequently, such products are used for casting:
- concrete;
- polyester resins;
- wax;
- gypsum.
According to consumers, liquid two-component polyurethane is also used in the field of medicine, where the material forms the basis of removable dentures. Polyurethane is often used also in the manufacture of jewelry. From it you can even pour floors that are characterized by durability, resistance to wear and high resistance to loads.
According to consumers, in some areas polyurethane parts are superior to steel in a number of ways. However, the manufacturing technology is much simpler, which allows you to get miniature parts and massive castings at the output, the first of which can weigh no more than a gram, while the second can have a mass of 500 kg or more.
More on mold polyurethane
A two-component polyurethane for the manufacture of molds is able to withstand a certain number of castings. If we are talking about ordinary brands, then stone casting can be carried out 1200 times at least. If the best materials were used in the mold manufacturing process, and the requirements for composing the mixture were met, then the mold will be ready to withstand up to 4000 castings. This is also true for the case when the mold was subjected to vacuum processing, and was also used for pouring not very abrasive, aggressive and adhesive materials.
Having familiarized yourself with the assortment of the international market, you can understand that today polyurethane is represented by several brands, among them it should be highlighted:
- volcoprenes;
- volcano
- adiprenes;
- poramolda.
If you prefer Russian brands, then you should choose NIC-PU 5, SKU-PFL-100. They are made from domestically produced polyesters, and the quality is no worse than their foreign counterparts. Moreover, in some respects they are leading.
Polyurethane brands differ in chemical composition, the number of urethane groups, the construction of the polymer chain and the molecular weight of the material. The properties can be regulated by careful selection of raw materials. As a result, it is possible to obtain branched and cast chains of polymers.
Polyurethane additives for molds
Two-component polyurethane for molds can be supplemented with different substances, namely:
They are necessary to improve the quality of the composition. For example, to speed up the reaction, modifiers are used that are added to small items. As for pigments, they are able to change the appearance of an element by color correction. In order to reduce the plastic content, fillers are used, which also make it possible to cheapen products.
Fillers can be:
- talc;
- a piece of chalk;
- carbon black;
- chemical, glass, carbon fibers.
However, this list cannot be called complete. Polyurethane forms for stone have color shades from light yellow to brown. If you use special additives, you can get almost any color.
Conclusion
Polyurethanes today have found their application in almost all areas of industry. Material is also used in everyday life. One of the promising areas is liquid two-component polyurethane. Its use simplified and accelerated the casting of concrete and gypsum. With the help of polyurethane, it became possible to produce small architectural forms, paving slabs and decorative elements even at home.