(1) The gel time of vinyl scales in winter is too slow. Due to the fact that the site is mostly two-component, the friends of the construction unit are not completely friends of scale glue, so they fight hard to add curing agents (commonly known as "white water"). ", methyl ethyl ketone peroxide), but it is still very difficult to grasp, work too slowly! !
(2) The more serious problem is the topcoat. No matter how much curing agent is added, the result is "tacky", but the topcoat in the scoop and the barrel is cured again, or even cracked. The topcoat is cured. If you don't go, the stickiness is severe.
(3) Winter "material", especially scale glue, is very thick, it is too laborious to scrape, what better way?
Ouyang analyzes the source of the problem:
(1) The curing mechanism of vinyl resin is free radical curing, which is a curing method that requires heat to maintain and is very sensitive to heat. Therefore, the nature of low temperature and slow curing cannot be changed. We can What is done is how to optimize the ratio of resin or rubber, accelerator, curing agent at low temperature;
(2) The second thing we can do is: how to formulate a more optimized and reasonable accelerator for the low winter temperature, especially at the lower temperature of the on-site carbon steel substrate. This generally refers to the winter mutual promotion Agent, which contains accelerator (such as dimethylaniline);
(3) The third thing we can do is: how to use methyl ethyl ketone peroxide with better curing effect, especially the lower temperature of the winter, especially the lower temperature of the on-site carbon steel substrate, especially after curing Curing agent, even to use mutual curing agent.
(4) The fourth thing we can do is that we should use accelerators, curing agents and formulating formulas according to the raw material resin used in the manufacture of glass flake cement. Each vinyl resin is different. Explained in detail later.
(5) The fifth thing we can do is: for topcoat, topcoat, how to treat it differently from the cement, optimize the ratio of accelerator, curing agent and liquid wax.
(6) The sixth thing we can do is to avoid conditions such as humidity and night construction, and improve the conditions of on-site construction as much as possible. This is really difficult in winter.
Next, I will analyze them one by one and talk about countermeasures.
(1) No matter which resin you use for vinyl scale cement and topcoat, in winter, I assume that everyone has no other better conditions. Ouyang suggests doing a few things:
1.1 Don't just rely on adding more curing agent on site to solve the problem of slow gelation. It is necessary to add more accelerators when manufacturing scale glue and topcoat at the factory. The specific amount is added. The scale glue manufacturer needs to test to confirm that each household Accelerator resins are not the same, and Ouyang is not good to say a specific number ratio across the board. Under normal circumstances, the downstream customers of scale mortar resin that follow the technical routes of Showa Polymer R-806EX (OY-8003EX) and H-630EX (OY-8071), the amount of Pro-EX accelerator in winter should reach 1% of the amount of resin ( If it is diluted twice, OY-1308 needs 2%), or even more, to ensure that the range of the gel time for the on-site cement with the curing agent to adjust the gel is relatively wide, and it is not necessary to add more than 5% of such exaggerated proportion of curing on site Agent methyl ethyl ketone; if the vinyl resin of other domestic factories (such as SW-901 in Taiwan, China) is the downstream customer of the resin technical route, the amount of winter accelerator SW-1305 added should reach 2.5% of the resin amount, or even More, to ensure that the on-site glue with a curing agent to adjust the gel time range is relatively wide, not to add more than 5% of such an exaggerated proportion of curing agent methyl ethyl ketone on site.
1.2 It is possible to bring some accelerators on the construction site to avoid the on-site gel being too slow. You can add some accelerators. This is currently the method used for most of the dry works, and it is also the most practical method.
1.3 It must be remembered that on-site solutions cannot be solved by adding more curing agents, but must be solved by linkage of accelerators and curing agents. This principle must be remembered in order to be able to mix ingredients on the spot.
1.4 It is important to remember that before large-scale construction and loading, a small experiment must be done to confirm the gel time, and this experiment is not done separately in the bucket or scoop. The site must be confirmed as follows:
First: Use a scoop to take roughly 1kg or 0.5kg of glue or topcoat (the default is to add accelerator or topcoat), and add a certain amount of the curing agent according to the advice given by the glue material supplier and the supporting curing agent. The curing agent is generally added to more than 2% of the amount of cement in winter, or even 4%. Stir well, and apply part of the glue or topcoat to the surface of carbon steel or the base material, about 2mm (the topcoat can be poured directly on the ground), and do not pour it in the scoop. Observe the initial setting time of the material in the scoop, this is the operable time for everyone to construct. This time must be shorter than the initial setting time on the surface of the substrate, because the materials in the scoop are concentrated, the heat is not easily lost, and the initial setting is faster. This time is best controlled at 30-60min, Ouyang in winter is not recommended to exceed 60min, once it exceeds 60min, the actual gel time of the final surface of the substrate and the topcoat after the coating will be very long, and it is easy to cause poor final curing . This phenomenon is more likely to occur when using the SW-901 mentioned above. It is relatively better to use the Showa system resin. This will be mentioned later. This is caused by the different curing properties of the resin. However, Ouyang still recommends that the initial setting time in the winter scoop should not exceed 60min to avoid unnecessary trouble.
Second: If the previous test is done, the time in the scoop is indeed too long, such as more than 60min, the best suggestion is: the materials supplied by the material supplier also have accelerators, and then go to within 1% of the amount of clay or topcoat (specific Just ask the material supplier) to add the accelerator to the mastic (the topcoat may be supplemented with a larger amount of accelerator), mix well and then use the curing agent to do the experiment. The final principle is the operating time 30-60min.
(2) How to formulate more optimized and reasonable accelerators in response to low winter temperatures, especially at lower temperatures on site carbon steel substrates.
This can be seen from the level of the cement manufacturers. Ouyang analyzed that the cement manufacturers in the industry currently have the following types of accelerators:
2.1 There is no technical ability to dilute concentrated cobalt (because many other additives are added) into the most optimized accelerator, so when buying resin directly, buy accelerators that are compatible with resin manufacturers, such as Pro-Ex, SW- 1305. This is also highly recommended by Ouyang, because after all, downstream manufacturers do not make resins, but only apply deep processing manufacturers. It is impossible to understand the resin and accelerators so deeply. Using accelerators to match them is generally not prone to problems. When a problem occurs, the technical staff of the resin manufacturer knows the approximate ratio of their accelerator to their own resin matching, and the technical service guided by the phone is easier. Resin manufacturers have blended other accelerators into the accelerators in the winter, whether it is Pro-EX or SW-1305 winter type, this is the reason. Users should not ask why, because people who make resins know more about how to match the most suitable accelerator in winter. For more inter-matching methods, Ouyang will not go into details on the 51fangfu public forum. This violates the unspoken rules. Each resin factory has its own way. It is just that Ouyang has a better understanding of this.
2.2 It is not excluded that the technicians of the mortar manufacturers with very cattle B buy 6～12% concentrated cobalt by themselves, dilute them by themselves, and adjust the formula by themselves. I have seen such manufacturers, but most of them have happened: Spring and autumn did not happen Problems, extreme low temperatures in winter are prone to problems, and extreme high temperatures in summer are also prone to problems. The problem in winter is to dry slowly. In summer, it is too late to add more curing agent, and it is like plasticine after three or four days of addition. The fundamental problem here is that these manufacturers feel that they are very cattle, and they are very likely to adjust the formula of the accelerator (in fact, they can save a small amount of money), but they do not know that they only adjust it themselves, and there will still be problems in the end.
2.3 The last one is the garbage manufacturer, which is completely cheap to apply. It directly uses the cobalt water accelerator that can be bought on the market for less than 15 yuan. If such cobalt water is used in summer, the problem will not be too obvious. In the winter, it will be in trouble. The reason is that the cobalt water is less than 15 yuan, where the cobalt content cannot be high (no one is stupid enough to do business at a loss and send money to everyone), which contains a lot of inactive solvents, such as toluene, solvent oil, etc. , Or even methanol. Due to the low cobalt content, a large amount of accelerator must be added in winter, so it is added to 4% of the resin amount, even more than 6%. Cheap, the accelerator is so cheap, it is cheaper than vinyl resin, and it can save money when added to it. It is not known that this kind of inferior accelerator is not dared to be used in the winter of making fiberglass, and it is only at best to make DS191 and other fiberglass. will use. There are a lot of non-reactive solvents that do not participate in the curing of the resin and are added to the mastic. Eventually, the mastic will not be cured, and even if it is cured, the adhesive performance, strength, compactness, and corrosion resistance of the mastic will be a series of The performance is very poor.
The above three situations: The third is garbage level; the second is understandable, but there are not many such masters; the first is relatively easy to control and a more reasonable choice. This is why resin manufacturers all recommend matching accelerators.
(3) How to use methyl ethyl ketone peroxide curing agent with better curing effect, especially the lower curing temperature of on-site carbon steel substrate, especially the post-curing curing effect, or even use mutual curing agent .
Poor-quality methyl ethyl ketone peroxide has too much hydrogen peroxide content, while the solidification of methyl ethyl ketone peroxide and methyl ethyl ketone dimer content is very low (this is high and the cost is high), which will lead to resin or cement It's a gel, but in fact, the post-curing can't go up, and eventually the cured plasticine appears. If you choose to use MEKP, it is recommended that you don’t choose too bad, and you need to use methyl ethyl ketone peroxide with a quality of V388. Of course, better is no problem.
In winter, MEKP can be mixed with other medium and high temperature curing agents (such as OT, TBPO, TBPB, etc.), which can play a role in secondary curing to a certain extent. However, this requires the cement manufacturer to understand the principle very well, and It must be well matched within the factory. This is very difficult. At present, Ouyang has not seen this level of scale cement manufacturers on the market.
Third, if you do not choose MEKP, but choose other curing agents such as CHP, the problem will change. I will not talk about other curing agents for the time being. Just talk about CHP (Cumene Hydroperoxide). Many curing agent manufacturers like to use this curing agent, and manufacturers such as Shangwei and Ashland have repeatedly recommended the use of this curing agent on the scale flakes on the market. Indeed, many Jingjiang manufacturers are also using it. But in fact they don't understand the principle inside. Ouyang talks a little bit here:
In general, the advantage is that the density is better, but I think CHP is more suitable for high temperature glass flake system in summer. In addition, CHP Ouyang is not recommended, especially in winter Ouyang is not recommended. The reason is that the intermediate temperature scales, due to the low temperature of the base material, cause the heat to dissipate quickly. The use of CHP artificially makes the curing degree of the intermediate temperature cement slowly. (Of course, if the maintenance time is sufficient, the use of CHP is still good. Your half-month maintenance time). In winter, the substrate temperature is lower, CHP will artificially reduce the overnight curing degree of the cement and topcoat. If I have no time, I still don't recommend it.
(4) We should use accelerators, curing agents, and formulate formulas according to the raw material resin used to make glass flake cement.
Each vinyl resin is different. This can only suggest to everyone whose resin they use, and ask their technical engineer. The difference between Ouyang and the current general technical service engineers in the market is that Ouyang himself has a formula origin. For either the Showa system resin, the Shangwei system resin, or the fumaric acid MFE system resin, let alone the OYCHEM system resin, Knowing the principle, I understand how the resins of different manufacturers are matched with accelerator curing agents, especially in the extreme high temperature summer and extreme low temperature winter. Don’t ask Ouyang why he knows that everyone has to make formulas like me for more than ten years, which is not surprising.
(5) For topcoats and topcoats, how to treat them differently from clay, optimize the ratio of accelerator, curing agent and liquid wax.
The amount of accelerator in the topcoat is added. Remember not to use CHP for curing. The best MEKP should be Aksu's Butanox LPT or Shuojin 925H. Regardless of whether to add powder in the topcoat, but it is recommended that everyone do the following:
5.1 Add liquid wax, how much to add, ask the manufacturers who sell resin to everyone, the resin factory supporting liquid wax will have a recommended ratio;
5.2 Do thixotropy as much as possible, and the thixotropy index should not be too low. Because after the vertical surface flows, the thinner the heat is, the harder it is to accumulate, and the harder it is to cure. And under the flowing state, the floating of the liquid wax will change with it. It is too easy to sag and it is also conducive to the formation of a layer of film on the surface of the liquid wax that is inhibited by oxygen.
5.3 It must be tested in the factory in winter to optimize the ratio. There should also be more accelerators on site (not only hair gel, topcoat, and curing agent in the past, but also accelerators in the past), to avoid the need for accelerators and curing agents to adjust the formula.
(6) Try to avoid conditions such as humidity and night construction, and improve the conditions of on-site construction as much as possible. This is really difficult in winter.
Construction can only be done at noon during the day, but the actual rush time is possible, and the current status of domestic projects Ouyang is very clear. It is impossible to have a hot air fan blowing hot air for you. You can only rely on yourself, get more people, and add more accelerators and curing agents.