What are the problems that occur during silicone construction?

Why does acid sealantfall off easily when used on cement?

This is actually one of the most basic problems in the application of silicone sealant. The acidic sealantproduces acetic acid when curing, which will react with the surface of alkaline materials such as cement, marble, and granite to form a chalky substance, thus causing fall off.

What causes neutral transparent sealant to turn yellow?

The yellowing of neutral transparent sealant is caused by defects in the sealantitself, which is mainly caused by the cross-linking agent and tackifier in the neutral glue. The reason is that these two raw materials contain "amine groups", and amine groups are very easy to cause Yellowing, many imported brand-name silicone sealants also turn yellow due to this reason. In addition, if neutral transparent sealantis used together with acidic silicone sealant, it may cause the neutral sealantto turn yellow after curing; it may also be caused by the long storage time of the sealantor the reaction between the sealantand the substrate.

Why do some silicone sealants come out with grains the size of salt grains, but some of them will automatically decompose after curing?

This is a problem in choosing the raw material formula of the glue, because the cross-linking agent contained in some glues will crystallize in a low-temperature environment. The cross-linking agent will condense in the sealantbottle, and you will see salt after typing it out. It is in the form of powder-sized granules, but it slowly melts, so the granules will automatically decompose after solidification. This situation has little impact on the quality of the glue. This situation occurs mainly because it is greatly affected by low temperature.

Why does the mirror surface have spots or traces of sealantafter a period of time when silicone sealant is applied to the back?

Mirrors on the market typically come in three different back coatings: mercury, sterling silver, and copper. It is common for mirrors to have speckles on the mirror surface after applying sealantfor a period of time. In this case, the user may have used acidic silicone sealant, and acidic silicone sealant usually reacts with the above-mentioned materials, causing speckles to appear on the mirror surface. Therefore, we emphasize that neutral sealantshould be used, and neutral sealantis divided into alcohol type and ketoxime type. If ketone oxime-type neutral sealantis used for a mirror with a copper base, ketone oxime will slightly corrode the copper material. After a period of construction, traces of corrosion on the back of the mirror will be seen outside the glue. If alcohol-type neutral sealantis used instead, This phenomenon will not occur. The above are all improper material selections caused by the diversity of substrates. Therefore, it is recommended that users do a compatibility test before using sealantto see if the sealantis compatible with the material. Only by choosing the appropriate silicone sealant product can unnecessary losses be avoided.

Under what circumstances can acidic silicone sealant not be used normally?

1. All materials that will exude grease, plasticizers or solvents.

2. An airtight place.

3. Frosted or damp surfaces.

4. Assembly of metal or coated glass.

5. It is not suitable for use in situations where it comes into contact with alkaline substances such as marble, granite, concrete, etc.

6. Acidic silicone sealants will corrode or fail to bond copper, brass (and other copper-containing alloys), magnesium, zinc, electroplated metals (and other zinc-containing alloys). It is also recommended that items made of masonry and iron carbide bodies Do not use acidic silicone sealants on substrates. This product will not work on materials made of methylmethacrylate (PLEXIGLAS), polycarbonate, polypropylene, polyethylene and TEFLON (Teflon, polytetrafluoroethylene). Get good bonding effect and good compatibility.

7. Acidic sealantis not suitable for connections that move more than 25% of the joint width. It is also best not to use ordinary acidic silicone sealant on structural glass. In addition, acidic silicone should not be used in places where there is corrosion or where substantial disadvantages will occur. Ketone sealant.

8. The temperature is too high or too low, and the humidity is too high or too low, which will affect the sealantdrying speed.

Why does neutral porcelain white silicone sealant turn pink? Some glues turn back to porcelain white after one week after curing?

Alcohol-type neutral silicone sealants may have this problem, which is caused by the titanium complex used in the production of raw materials. The titanium complex itself is red, and the porcelain white color of the sealantis due to the titanium dioxide in the sealantplaying a toning role. But sealantis an organic substance, and most organic chemical reactions are reversible reactions, and there are also side reactions. Temperature is the key to causing these reactions. When the temperature is high, a positive reaction occurs and the color changes. However, after the temperature drops and stabilizes, the reaction proceeds in the reverse direction and returns to its original appearance. If the production technology and formula are well mastered, this phenomenon should be avoided.

Why does acidic silicone sealant sometimes bubble on the surface a few minutes after it is applied on a stainless steel door?

The compatibility of acidic silicone sealant with stainless steel is not very good. It is generally not recommended to use acidic silicone sealant on stainless steel. The main reason for blistering is the quality of stainless steel. In order to reduce costs, some stainless steel manufacturers make stainless steel contain more impurities. Acidic sealanthas a low PH value and is highly acidic. Acidic substances will react with this kind of stainless steel, so it releases bubble.