Relationship between isocyanate and polyurea elastomer
发布时间： 2018-08-17 16:31 Author: Polyurethane foam machine Source: http: //motokone.com
Published: 2018-08-17 16:31
The presence of MDI isomers in the prepolymer has little effect on the gel time of the polyurea system, but it can significantly increase the fluidity of the polyurea material system. As shown in the test data in Table 2-6, with the increase of the content of MDI isomers, the mechanical properties such as hardness and tensile strength of polyurea materials decrease significantly.
In summary, through the analysis of the relationship between the isocyanate, diluent, and R component chain extenders in the A component and the properties of the polyurea elastomer, considering the two factors of excellent gel time and excellent performance, formula 3 was selected as the pumping oil Anticorrosive polyurea coating formulation for corrosion resistance test.
(1> Adding an appropriate amount of propylene carbonate ((PC) to the A component can not only reduce the viscosity and improve the mixing and improve the mixing efficiency of the system, but also make the polyurea system reaction proceed smoothly and improve the mechanical properties of the elastomer. Improve the leveling properties of the film. With the increase of the content of MDI isomers, the mechanical properties such as hardness and tensile strength of polyurea materials have decreased significantly.
C2) When designing a good formula for the R component, consideration should be given to selecting a low-molecular chain extender with a suitable reaction rate; an increase in the amount of the chain extender increases the reaction speed of the polyurea system, and the gel time is significantly shortened. The influence of body mechanical properties is small, and the pre-control of gel time of sprayed polyurea elastomer can be achieved by adjusting the type and content of chain extender in the polyurea system formula.
(3) When designing the polyurea formula, the influence of the following factors on the properties of the polyurea elastomer should also be considered, such as the isocyanate purpose index and functionality.
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