How to discern the stand or fall of caulking agent

Caulking agent product market is very hot, so many brands on the market. So how to discern the stand or fall of caulking agent? Ready to buy after filled seam an agent, but I do not know how to distinguish good or bad products, do not know how to buy related products, then by caulking small make up from the smell, the curing time, color, hardness and resistance to yellowing this five aspects to teach you to distinguish caulking agent of quality. , smell: the smell is bigger, stimulating odour, harmful gas that product is more, affect your health. 吗? And cure time: a two-component caulking agent in commonly - curing time Hours to moderate curing advisable, winter needs to extend, short curing time, show strong chemical reaction, prone to harmful gas, a long curing time, curing agent of poor quality, low price comparison. 吗? , colour and lustre, caulking product luster when dry, smooth, also from the side reflect curing agent, mainly is your choice of paint. Ordinary color toner curt, reflective strong strength, the light is more rigid, brand caulking agent USES the pearl powders, the light is downy, with pearl luster and good transparency. 吗? , hardness, hardness is not as hard as possible, to soft with just like wire, not only has the hardness of iron, and it has good toughness. 吗? , yellowing resistance: ordinary brand of yellowing resistance of gap filling agent, yellowing phenomenon in a one or two years later, affect the whole beautiful. Caulking agent aging, also need time to verify, there are many factors that can aging, such as air oxidation, thermal effect, chemical effect of the key of the fracture. 吗?