תהליך סינתזת דבק מבני פוליאוריטן וטכנולוגיית בנייה

Polyurethane Structural Adhesives In the synthesis process of polyurethane, by controlling the polymerization reaction, the ratio of the hard and soft segments of the polymer can be adjusted, so as to regulate its elasticity, cold resistance, as well as the hardness and mechanical strength of various properties. Polyurethane has high tensile and tear strengths, up to 70 MPa, and excellent elasticity, even when hardness is high. And at room temperature, it has good oil resistance, good resistance to oxygen, ozone and resistance to ultraviolet radiation effect. Next, Xianjie.com will introduce the characteristics of polyurethane structural adhesive, shortcomings and improvement methods, construction process, general performance, application areas, purchase precautions, synthesis methods, and the difference between silicone structural adhesive.
　　Construction process of polyurethane structural adhesive
　　1、Preparation work:
　　① mixing glue with an empty barrel, requirements: clean and dry, or use just loaded with the main agent of the barrel;
　　② glue mixing tools: manual mixing stick or electric mixer;
　　③ electronic scale: to be able to accurately weigh to one decimal place is preferred;
　　2、Surface treatment of substrate.
　　The surface of the substrate should be dry, no grease, no dust or other dirt (can be cleaned with ethanol, acetone, etc.), if the metal surface is coated with primer, the plastic surface of the emission agent is removed, the surface to be adhered to be sanding treatment, the adhesive force will increase significantly;
　　3, mixed glue:
　　If the glue has been stored for a certain period of time, the main agent should be mixed well first, after mixing the glue according to the proportion, please use up the glue within the applicable period, try to use up the glue in advance, if not, then you can take a small amount of the principle of multiple times;
　　4, sizing:
　　Available with a serrated scraper manually apply glue or glue with a roller, the surface of the substrate should be evenly sized, the specific amount of glue according to the roughness of the surface of the substrate varies;
　　5, pressure:
　　Already sizing the substrate needs to be pressed within the open time, otherwise it will affect the bonding strength;
　　6, pressure application time:
　　According to different temperatures, different curing speeds, the formation of adhesion time is also different, the temperature decreases, the curing speed becomes slower, the need to extend the pressure application time. Temperature increases, the curing speed becomes slower, the need for pressure time is short;
　　7, unpressurized:
　　After a certain press time, the composite board can be moved down, at this time the composite board has a certain strength, can be carried, installed or do the next step in the process, the final adhesion is formed after a number of days;
　　8, cleaning:
　　Uncured glue can be removed by special cleaning agent, cured glue can only be removed by mechanical methods;
　　9, Precautions:
　　Whether it is the main agent or curing agent, it should be isolated from the air during the preservation process, because the water molecules in the air will be absorbed, leading to the formation of air bubbles, resulting in the degradation of the product performance, so the containers holding the glue must be sealed.