The common problems of glass glue

Do you know the common way to deal with glass glue?

  1. What is the reason for the neutral transparent plastic to turn yellow?

Neutral transparent adhesive yellowing is a defect in the glue itself, mainly caused by the cross-linking agent and tackifier in the neutral gel, because the two raw materials have an “amine group”, and the amine group is extremely easy to cause Yellowing. In addition, if the neutral transparent adhesive is used together with the acid glass glue, it may cause the neutral glue to turn yellow after curing. It may also be caused by the long storage time of the glue or the reaction of the glue with the substrate.

Second, why does neutral porcelain white glue become pink? Some rubbers turn back to porcelain white one week after curing?

This phenomenon may occur with alcohol-based neutral gels, which are caused by the production of raw material titanium chromite. The titanium chrome compound itself is red, and the porcelain white color of the glue is the coloring effect of the titanium white powder in the glue. However, the glue is organic, and most of the organic chemical reactions are reversible reactions, as well as the production of side reactions. The temperature just happens to be the key to these reactions. The temperature is high and the positive reaction causes the color to change. However, after the temperature is lowered, the reaction is reversed and the original state is restored. The production technology and formula are well mastered and should be avoided.

  1. Why do some transparent glass glues change into porcelain white color after five days? Neutral green glue becomes porcelain white after construction, why?

This should also be a problem in the selection and verification of raw materials for plastics. Because some domestic rubbers are added with plasticizers, they are easy to volatilize; while some rubbers have more reinforcing fillers. When the plasticizers volatilize, the rubber strips are stretched due to shrinkage, and the filler color is present (all fillers of neutral rubber) It is white in itself). Various color glues are added with pigment to make them into various colors. If there is a problem with the choice of pigments, the color of the glue will change after construction; or the color glue is too thin during construction, and the glue is inherently small in the curing process. Shrinkage will make the color of the glue lighter. In this case, it is recommended to maintain a certain thickness (3mm or more) when applying the glue.

  1. Why is the glass glue on the back of the mirror? After a period of time, there are traces of spots or glue on the mirror surface?

There are usually three different backside coatings on the market: mercury, sterling silver and copper. The common mirror is smeared for a period of time after the speckle appears on the mirror. In this case, the user should use acid glass glue, and the acid glass glue usually reacts with the above materials to cause the speckle to be seen on the mirror surface. Therefore, we emphasize that neutral gel should be used, while neutral gel is divided into two types: alcohol type and ketone type. If the mirror of the copper bottom is made of ketone oxime type neutral glue, the ketone oxime will be slightly corroded to the copper material. After a period of construction, the mirror surface will see corrosion marks on the back sizing place. If it is changed to alcohol type neutral glue This phenomenon does not occur. All of the above are due to improper selection of substrates. Therefore, it is recommended that the user do a good compatibility test before using the glue to see if the glue is compatible with the material. Use the right glass glue to avoid unnecessary losses.

  1. Some glass glues are salty-sized granules when they are shot out, and some granules will be automatically solved after curing. Why?

This is a problem in the formulation of raw materials for selecting glues. Because some of the cross-linking agents contained in the gel are crystallized in a low temperature environment, the cross-linking agent condenses in the gel bottle, and when it is shot, it will see a salt-like granular shape, but it slowly Will melt, so the granularity will be automatically solved after curing. This situation has little effect on the quality of the glue. This situation is mainly caused by the influence of low temperature.

Sixth, some glue hit the glass, 7 days still not dry, what is the reason?

Most of this happens when it is cold. First, the glue is too thick, and the dry glue is slow. Second, the construction environment is affected and the weather is bad. Third, the glue expires or has problems. Fourth, the rubber is soft and it feels dry.

Seven, some glass glue in the sizing of the bubble sound, what is the reason?

There may be three reasons: First, the technology is not closed when dispensing, the air is mixed in the plastic bottle; Second, the air is left in the bottle; Third, it is not 100% silicone rubber, and the added filler will be mixed with the glass plastic bottle. The PE soft rubber has a slight chemical reaction, which causes the rubber bottle to expand and increase. The air remaining in the space penetrates into the glue to make a gap, and a bubble sound is generated when the glue is applied. An effective way to overcome this phenomenon is to switch to a hard bottle and pay attention to the product storage environment (lower shades below 30 °C).

  1. Why do you use glue in high temperature weather, and some neutral glue will have many bubbles after curing at the joint of concrete and metal window frame, and some will not? Is it a quality issue? Why hasn’t there been a similar phenomenon before?

Many brands of neutral rubber have had similar phenomena. After careful testing and repeated experiments, it is not the quality of the glue. Because the neutral gel has two types of alcohol type and ketone oxime type, the methanol contained in the alcohol type gel will release gas during the curing process (methanol starts to volatilize at around 50 ° C), especially in the case of direct sunlight or high temperature reaction. . In addition, concrete and metal window frames are difficult to breathe. In addition, the summer temperature and humidity are higher, the curing will be faster, and the gas released by the glue can only be run out of the fully cured rubber layer. There will be bubbles of different sizes. The ketone oxime type neutral glue does not release gas during the curing process, and no bubbles are generated. However, the shortcoming of ketone oxime type neutral glue is that once the technology and formula are not handled well, there is a chance of shrinkage cracking when it is cold in the curing process in winter. The technology is good, and there is no such phenomenon when the formula passes.

In the past, there was no similar phenomenon because in the past, construction units used less silicone rubber in this place. Generally, propylene-based waterproof sealing materials were often used. Therefore, the phenomenon of silicone neutral rubber foaming is not very common; The silicone sealant has been widely used, which has greatly improved the quality of the engineering, but the foaming phenomenon of the sealant is caused by improper selection of materials.

To solve such problems, we should pay attention to the following points: First, the prudent approach is to do a partial use test to see if it meets the needs of use (the reaction can be seen in two or three days after the sizing); The type of substrate, choose the right neutral glue to use: choose ketone oxime type in summer, choose alcohol type in winter; 3. keep the construction surface clean and dry; 4. avoid high temperature time (above 35 °C) and sun in summer sizing Direct, generally suitable for the evening.

How to do compatibility testing?

Strictly speaking, the compatibility test between the adhesive and the building substrate should be carried out in the state-approved building materials testing department. Of course, the necessary engineering must be qualified by the national authoritative testing agency. In order to determine whether to use a building material product, the general engineering can provide the substrate to the manufacturer of the glass glue for compatibility testing. The structural adhesive is 45 days, and the neutral rubber and acid glue can be obtained for about 35 days. The quick and easy way is that the user can test the glass glue on a small amount of substrate. After fully curing, observe the surface effect and try to test the peel strength of the glass glue to determine whether the adhesion, tension and the like of the glass glue product are consistent. Need to use.

  1. Why is acid glue used on cement to fall off easily?

This is actually a basic problem in the application of glass glue. Acidic acid produces acetic acid during solidification and reacts with the surface of alkaline materials such as cement, marble, granite, etc. to form a chalky substance that causes shedding.

 

Source: Sina real estate door and window madman