For Acid Silicone Sealant, What Are The Common Problems?

As we all know, silicone sealant can be divided into acid silicone sealant and neutral silicone sealant, acid silicone sealant has very good elasticity and bonding, its use is very wide, can be used for most of the decoration building materials between the bonding, such as glass, aluminum, oil-free wood and so on. However, it should be noted that acidic silicone sealant can not be used to stick alkaline building materials such as ceramics and marble. Otherwise, the substances in the acid silicone glue will react with the alkaline substances in the building materials, thus affecting the quality of the decoration of the building materials. Here is a look at the actual problems that acid glue is prone to:

1. Acidic silicone sealant bottle will grow tall, deformed and even have oil in the bottle after storage for a period of time, why?

There are two reasons for this problem, that is, it is related to the glue and the glue bottle.

First, the reason for the glue. The acidic glue on the market now, in addition to a few high-grade glue, other acidic glue are different degrees of adding a certain amount of filler to reduce costs, and the lower the grade of the glue, the more the amount of filler added, and the filler will react with the glue bottle, so that the glue bottle is tall, deformed and the bottle has oil; If the high-grade glue may make the glue bottle react after 6 months, the relatively low-grade glue may react within 6 months.

Second, the glue bottle reason. The quality of the material of the plastic bottle itself is also the reason for the growth of height, the raw materials used in the bottle are also good and bad, the raw materials used are good, the trend of change of the plastic bottle is relatively slow. Such as good quality plastic bottles, loaded with high-grade plastic can be stored for 78 months without reaction; On the contrary, the use of poor quality plastic bottles, even if the better glue may be deformed in 2-3 months.

2. Why is the glue found thick or dry when looking at the bottom of the bottle?

This is mainly produced during the packaging process. Because it takes a certain amount of time from loading to pressing the cover, although the time is short, it also makes the glue contact with the air. If the sealant cures a lot from the bottom, it is caused by the tight seal between the bottom cap and the bottle, which is a quality control problem of the packaging material.

3. Acid silicone sealant extrusion process will break or there are small bubbles, why?

This situation is mainly caused by the following two reasons.

First, the storage temperature is too low: if it is acid glue (especially low-grade glue) stored at a lower temperature, it will form a lot of bubbles. The reason may be that after low temperature storage, the liquid raw material changes due to the shrinkage volume and forms more bubbles, so it is recommended that the storage temperature should not be lower than 0℃.The second is the formation of the canning process: in the normal canning, the glue tail will often have a small number of small bubbles, if there are more bubbles or flow (large bubbles), it is caused by improper operation, which must be improved and should be avoided. However, this situation also has the probability of occurrence, if the phenomenon is rare or occasionally, it should be regarded as a chance event. Large bubbles should be avoided during operation.

4. Why does the surface wrinkle after acidic silicone sealant curing?

This is mainly caused by the thin adhesive layer when the surface of the two substrates is gummed. Due to the different thermal expansion and cold contraction rates of different materials, the temperature difference is large, and the incomplete solidified glue will be deformed and wrinkled.

Solution: the adhesive layer is coated thick, the thickness of the adhesive layer is generally about 1mm during construction, and it is recommended to increase the thickness to (1.5-2) mm.

5. Why does some acetic silicone sealant make aluminum discolor after curing?

When the acid silicone sealant is cured, it releases acetic acid, which is corrosive to metal materials. The reason why it can be used on aluminum is that the aluminum surface is coated with an oxide film or coating for protection. Therefore, in general, the discoloration of aluminum is not a problem of glue, which involves more problems of construction operation and the quality of aluminum itself. The quality of aluminum mainly refers to the unqualified coating layer of aluminum coating, such as poor adhesion, film layer is too thin, etc., will cause its discoloration after sizing; Improper construction will also cause discoloration, if the aluminum is placed in a poorly ventilated environment after sizing, resulting in the acetic acid released by the solidification of silicone sealant can not be dispersed in time, the local concentration is too high, and the corrosion of aluminum for a long time causes it to change color.

6. The adhesive strip will turn white or yellow after curing, why?

White: the white of silicone sealant is mainly due to too much filler added in the sealant; If occasionally there is a white situation, many times it appears in some projects where the glue layer is too thin, so it is recommended to increase the thickness of the glass glue appropriately (1.5-3mm) when sizing to avoid similar situations.

Yellowing: In more cases, the yellowing of the rubber strip is caused by the influence of other materials in contact with glass glue, the most common is the glass glue played on some black rubber strips (sealed between glass and aluminum), because some of the quality of the rubber strip is poor, contact with glass glue makes it yellow, even imported rubber is no exception. Under normal circumstances, the rubber strip changes the color of glass glue, and the reason may be the material used in the rubber strip, which is the reaction between the filler and the acid glue to make the transparent rubber change color; It does not exclude the addition of precipitated or volatile substances in the rubber strip, polluting the glass strip.

7.Why will the silicone sealant on the paper there will be some sticky paper, some non-sticky paper situation?

Glass glue is not used to stick paper, so sticky paper and non-sticky paper will not affect the actual use; However, the adhesion of paper is related to some characteristics of paper and glass glue. First of all, the material and texture of the paper have a great impact on the adhesive paper, such as the paper fiber is loose, the glass glue is easy to wet the paper, thereby sticking the paper; Secondly, glass glue also has an impact, and the preliminary analysis has a certain relationship with the curing speed, such as low-grade glue curing slow, easy to stick paper.

8. Why does the cured hyaluronic acid strip turn white after stretching?

Because many acid adhesives add solid fillers to increase strength, the solid fillers show white after stretching, so it looks white.

9. Why does the deep curing of silicone sealant slow?

Deep curing has a great relationship with the use of the environment, under normal circumstances, in the low temperature, high humidity in the environment of glass glue curing slower; In addition, curing is slow in poorly ventilated environments; There is a large difference in the curing speed of different grades of glass glue, and the curing speed of low-grade glue is significantly different than that of high-grade glue, and the difference is especially obvious when the ambient temperature is low, so it is recommended that low-grade glue should not be used near the specified lower limit temperature (5 ° C).

10. Why does silicone sealant shrink after curing?

All sealants shrink after curing, but high-grade and low-grade adhesives differ greatly in shrinkage rate. For example, high-grade glue only shrinks by 5% after curing, and low-grade glue may shrink by 30% or more, because low-grade glue is added to the filler, and the filler will slowly evaporate in the air, so the more the filler, the greater the shrinkage rate.

11. Is there a small amount of oil separating at the mouth of the bottle?

This is a normal phenomenon of long-term storage, generally stored for more than 3 months, but the probability of this situation is not very high in practice, because the separation of glass glue oil will occur in the case of a long standing time, and the support glue is often in motion due to sales, such as transportation, loading and unloading, sorting out the warehouse, which is equivalent to constant stirring. So you don't have stratification much of the time. The reason for a small amount of oil separation is that the product is composed of liquid raw materials and solid raw materials, due to their different specific gravity, there will be a sinking phenomenon in the case of long-term standing, but because the process is very slow, it does not affect the use and product performance.

12.Why the dry time of silicone sealant too fast, no dressing time?

This is related to the construction temperature and operation. It is recommended to avoid high temperature weather during construction, increase the number of trimming, if the original finish 2 meters long glue seam before trimming, you can change to finish 1 meter long glue seam after trimming, which can reduce the adverse impact caused by too fast drying.

13. There is oil seepage on the paper, why?

First of all, different paper due to its texture, material and other factors, such as some paper fibers are loose, so the filler added in the low-grade glue will penetrate into the pores, resulting in oil seepage; However, after experimental observation, this situation does not appear in actual use, that is, there will be no oil seepage on aluminum and glass, and it will not affect the adhesion, strength and other properties.

14. High grade glue is more non-stick aluminum, why?

Because its curing speed is too fast, the adhesive paste does not completely infiltrate the surface of the aluminum, that is, it cannot penetrate into the microholes on the surface of the substrate without sticking. This phenomenon does not affect the normal use of glass glue. High-grade glass glue mainly has two uses, one is a large glass curtain wall or point-type curtain wall, glass glue used here only contact glass, not contact with other materials, so it does not matter if it does not stick aluminum; The second is used for glass aluminum alloy door and window caulking, glass glue is filled in the joint between glass and aluminum alloy, although the glass glue and aluminum alloy bonding force is not good, but because of the good glass bonding, will not fall off, as a caulking seal use and do not bear the load (that is, do not force), so as long as it can adhere to the aluminum alloy can play a sealing role.

15.Acetic silicone sealant inside crystallization?

This phenomenon only occasionally appears, mainly caused by the storage temperature is too low, because the additives added to the acid silicone sealant system have many high freezing point, although the additives have been integrated into the glue, but at a long time at low temperature will still be re-crystallized and precipitated, so the storage temperature to avoid too low.

16. Acid silicone sealant turning red?

This phenomenon has only occasionally appeared, mainly caused by the instability of raw materials, so it is necessary to control the inspection of raw materials.