What are the factors that affect the curing of Urethane Grout
First, the curing agent, accelerator added to the impact of Urethane Grout curing, solid only curing agent to heat more, have a higher degree of curing. Only when the temperature is high, the amount of the accelerator can be reduced slightly to obtain a sufficiently long gel time and a more complete degree of cure. The molar ratio of the general accelerator to the curing agent (peroxide) must be less than 1, otherwise the reverse reaction rate will be greater than the rate of the primary free radical initiated monomer, resulting in a decrease in the conversion rate. So too much use of accelerators can not achieve the effect of accelerated curing, but will reduce product performance.
Followed by the nature of Urethane Grout itself also have the image. The density of the double bonds in the molecular chain of the linear unsaturated polyester polyurethane is as measured by the percentage of the total number of moles of the unsaturated dibasic acid contained in the molecular chain. The so-called high reactivity, medium reactivity, Reactivity generally refers to: unsaturated dibasic acid accounted for more than 70% of the high reactivity; 60-30% of the middle reaction activity; and unsaturated dibasic acid accounted for 30% or less were low reactivity.
In the uncured liquid UPR, to join the inhibitor, so that UPR goods in the storage process from premature gel deterioration. The initiator and the promoter react to release the free radicals, which were initially consumed by the polymerization inhibitor, and the polymerization inhibitor became stable. Therefore, the low reactivity of the Urethane Grout may be due to the addition of the inhibitor amount is very small and appears to have high reactivity, and high reactivity of the Urethane Grout may also be due to the addition of a large number of polymerization inhibitor becomes less active The In addition, Urethane Grout in the filler, color paste, low shrinkage additives, etc. will also affect the degree of Urethane Grout curing. The higher the unsaturated double bond content in the unsaturated polyester molecular chain, the higher the reactivity of the Urethane Grout, and the shorter the time to complete cure. The ratio of two double bonds of trans - double and cis - double bonds in linear unsaturated polyester. The higher the trans-double bond content, the higher the degree of cure. Urethane Grout should have enough styrene content, too much or too little will make Urethane Grout curing bad. Urethane Grout inhibitor and other additives in the impact.
Construction environment The higher the temperature, the shorter the gel and curing time. Sometimes the construction temperature increased by 10 ℃, can shorten the gel time by nearly 1/2. If the construction environment temperature is too low, easy to cause permanent undercorrection. Because the Urethane Grout at low temperatures, although able to gel, but after the formation of macromolecules can not move, because there is not enough exothermic peak temperature caused by the release of free radicals free agent, making the chain reaction is not easy, and ultimately lead to permanent Of the undercuts. General requirements of the construction temperature of not less than 15 ℃, relative humidity of not more than 80%.
Different manufacturers of different batches of Urethane Grout curing speed is different, while the construction by the ambient temperature, humidity and many other factors, the product of the best degree of curing time will be different. Urethane Grout on the market do not understand the quality is not the same, to seriously identify. High-quality products, its performance is relatively stable. Curing is a complex chemical process, affected by many factors, therefore, whether it is UPR manufacturers, or application manufacturers should have some basic knowledge of UPR curing, in order to safety, improve production efficiency, based on their own products The characteristics of an effective solution to the actual production of the various problems. I believe that with the application of manufacturers of Urethane Grout curing knowledge of the deepening understanding of their production of product quality will be a qualitative leap.