Two-component polyurethane is a polymer that is made by mixing two ingredients. The first is isocyanate compounds, while the second may be compounds of the hydroxyl group. The elements interact to form a polymer with a polyurethane structure.
Varieties of polyurethane
To obtain a polymer, it will be necessary to mix the hardener and base in certain proportions. Two-component polyurethane can be represented by cold and hot polymerization. The latter version of the material requires exposure to elevated temperatures, while the former polymerizes at natural temperature.
Main Features
The described materials that are used for molds have high strength characteristics, they are resistant toaggressive environments and harmful effects, as well as elevated temperatures. All these features expand the scope of polyurethane. It is suitable for production:
- colors;
- adhesives;
- sealants;
- varnishes.
After mixing the components, the composition acquires excellent fluidity, which makes it possible to make parts from it using casting technology. As an example, bushings for mechanisms can be distinguished. In the article we are talking about a two-component polyurethane injection molding variety. The properties of the material are determined by the original components. In this case, the composition of the isocyanate hardener and base is important.
Additional Features
Material properties may change depending on the addition of different substances, such as fillers and dyes. Some polyurethanes replace rubber, because they are highly elastic. You can find polyurethanes that are able to restore their original shape in case of mechanical damage, which makes them especially valuable in industry.
Overview of areas of use
Two-component polyurethane is widely used today. The material is used for making jewelry, various mechanisms and casting gears. The operational properties of the obtained parts are quite high. This allows the material to be used even in difficult conditions. As a result, it is possible to obtain viscous, hard and chemically resistant parts. The latter can be:
- gears;
- shafts;
- pulleys;
- wheels;
- rollers;
- timing belts;
- sealing elements;
- various protective coatings;
- couplings;
- pipelines;
- bearing parts;
- bushings.
Parts are ready for high quality and long service life, 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. They are ready to work even if the tread is damaged.
The material forms the basis of supporting and guide rollers, which are operated in conjunction with belt and conveyor conveyors. Elements are ready to last much longer than rubber gear belts, tracks and tracks.
The material is used for shock absorbers and sealing elements, because it is more resistant to wear and strength. That is why rubber parts have recently been increasingly replaced by polyurethane. At the same time, elasticity remains at the same level. Two-component cast polyurethane has found application in the production of pipelines, which are characterized by chemical resistance and strength. The elements are complete. In addition, with the help of the material, pipelines can be protected not only from the inside, but also from the outside.
Feedback on additional uses
According to consumers, two-component polyurethane is used in the productionadhesives and paints and varnishes. 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 resin;
- wax;
- gypsum.
According to consumers, liquid two-component polyurethane is also used in the field of medicine, where the material is used as the basis for removable dentures. Polyurethane is quite often used in the manufacture of jewelry. It can even be poured into floors, which are characterized by durability, wear resistance and high load capacity.
Polyurethane parts outperform steel in some areas, according to consumers. However, the manufacturing technology is much simpler, which makes it possible to obtain miniature parts and massive castings, the former of which can weigh no more than a gram, while the latter can weigh 500 kg or more.
More about mold polyurethane
Two-component polyurethane for mold making can withstand a certain number of castings. If we are talking about ordinary brands, then stone casting can be carried out at least 1200 times. If the best materials have been used in the mold production process and the mixing requirements have been met, then the mold will be ready to withstand up to 4000 castings. This is also truefor the case when the form was subjected to vacuum processing, and was also used for pouring not very abrasive, aggressive and adhesive materials.
Familiarizing yourself with the range of the international market, you will be able to understand that polyurethane today is represented by several brands, among them it should be noted:
- vulcoprenes;
- vulkollans;
- adiprenes;
- poramoldy.
If you prefer Russian brands, then you should choose NITs-PU 5, SKU-PFL-100. They are made from polyesters of domestic production, and the quality is no worse than foreign analogues. Moreover, they are leaders in some parameters.
Polyurethane grades differ in chemical composition, the number of urethane groups, the construction of the polymer chain and the molecular weight of the material. Properties can be adjusted by careful selection of raw materials. As a result, branched and cast polymer chains can be obtained.
Polyurethane mold additives
Two-component polyurethane for molds can be supplemented with different substances, namely:
- modifiers;
- fillers;
- dyes.
They are necessary to improve the quality of the composition. For example, modifiers are used to speed up the reaction, which are added to small products. As for pigments, they are able to change the appearance of the element by color correction. In order to reduce the plastic content, fillers are used, which also make products cheaper.
Fillers can be:
- talc;
- chalk;
- carbon black;
- chemical, glass, carbon fibers.
However, this list cannot be called complete. Polyurethane molds 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. The material is also used in everyday life. Liquid two-component polyurethane is one of the promising directions. Its use has simplified and accelerated the work of casting from concrete and gypsum. With the help of polyurethane, it became possible to produce small architectural forms, paving slabs and decorative elements even at home.
