The thickening properties of vinyl resins have always been the research direction of various manufacturers. Especially with the application of BMC/SMC in automotive parts, thickened vinyl resins should have better impregnation properties and rheological properties, allowing the resin Molding products under lower pressure
Vinyl resin can withstand higher impact force than general-purpose unsaturated resin, and has good creep resistance and fatigue resistance. It can be used for wheels, tables and chairs, cooling racks, grille plates, engine valve sleeves and electrical insulation products, industrial pump valves, golf heads, etc.
As a thickening vinyl resin, the resin naturally requires the following characteristics:
1. Good wetting with reinforcing materials and fillers;
2. The initial low viscosity and rapid thickening characteristics;
3. Good mechanical properties, including human nature and fatigue resistance, etc.;
4. Long storage period;
5. Lower curing exotherm peak and lower styrene volatilization.
In order to achieve the effect of use, a more common method in the study of vinyl resin synthesis is to introduce acidic functional groups (carboxylic acids) on the vinyl ester molecules, and use these carboxyl groups and alkaline earth metal oxides (such as magnesium oxide, calcium oxide, etc.) However, this method takes a long time to thicken, and it usually takes several days to react with the aqueous cyanate and polyol to produce a network structure, thereby achieving rapid resin thickening. This method can be applied to low-pressure molding. It has the characteristics of stable viscosity control, low temperature and humidity requirements, and long storage period. The interlayer bonding strength of the product is high. At the same time, low acid value resin with excess alcohol can also be used as a thickener. .
The thickening properties of vinyl resins are the basis of vinyl resins in BMC/SMC applications.