Structural adhesives have high strength, can withstand large loads, are resistant to aging, fatigue, and corrosion, and have stable performance within the expected life span. They are suitable for adhesives that bear the bonding of structural parts. It is mainly used for bonding metal, ceramics, plastics, rubber, wood, etc. or between different kinds of materials, and can partially replace traditional connection forms such as welding, riveting, and bolting. The following is a detailed introduction to how to use the structural adhesive and how to use the silicone structural adhesive.

1. How to use structural adhesive?

1) Silicone structural adhesive should be used in a clean environment with a temperature of 5°C-405°C and a relative temperature of 40%-80%r, so that a better bonding effect can be obtained.

2) Temporary protective tape should be attached to the area near the surface of the cleaned substrate to be bonded. If you want to use the primer, it should be done before applying glue.

3) The one-component structural glue can be directly squeezed out of the plastic tube or sausage-type packaging by manual or pneumatic sizing. The two-component structural glue must be sized using special sizing and mixing equipment.

4) The extrusion action of the structural glue should be carried out continuously, so that the glue is evenly and continuously extruded out of the glue nozzle in a cylindrical shape, and the diameter of the nozzle should be smaller than the thickness of the nozzle, so that the nozzle can extend into one-half of its depth . The gun nozzle moves evenly and slowly to ensure that the interface is filled with sealant to prevent bubbles or cavities from moving too fast.

5) Trim immediately after the glue injection is completed. The usual method is to use a scraper to press the extra structural glue outside the interface into the interface and sequentially scrape the interface surface smoothly so that the glue contacts the side of the interface, and then remove all Temporary protective tape.

Immediately after the above process, a label with the date and number should be affixed to the unit, and the unit should be played horizontally in the curing area for maintenance. During the handling process, the aluminum frame and the upper glass should not be allowed to cause any displacement or misalignment. Otherwise it will affect the bonding quality of the structural adhesive.

6) The curing area must be clean, with good ventilation conditions, and the temperature should be maintained at 5°C-40°C. The relative temperature should be kept at 40%-80%; if the temperature is lower than 50%, the maintenance time of the unit should be extended.

7) The single component must be cured for sufficient time under static and unstressed conditions, including at least 21 days for the one-component structural adhesive and at least 14 days for the two-component structural adhesive to make the structural adhesive produce sufficient adhesion. The unit products can only be shipped and installed after the rubber cutting inspection is qualified.

8) The user should pay attention to the double-sided adhesive coating method when the design width of the glue joint is greater than 16mm, that is, the double-sided adhesive tape is placed in the middle of the glue joint, and the glue is applied on both sides of the adhesive tape to speed up the curing speed of the glue. Avoid affecting the deep curing of the adhesive due to the poor air permeability of the double-sided adhesive tape.

2. The use and requirements of structural adhesives

1) Structural glue should be constructed in a specially set glue injection room. The glue injection room is required to be clean, dust-free, no fire, and ventilated. The indoor temperature should be controlled at 23±5°C, and the relative temperature should be controlled at 70%±5%. Glue injection operators must receive special business training and pass the actual operation assessment before they can work with a certificate. It is strictly prohibited to use expired silicone structural adhesives, and it is strictly prohibited to use silicone structural adhesives that have not undergone compatibility tests, butterfly tests and other related inspections and have passed all inspection parameters.

2) Clean the place where the glue is injected. Use cleaning agents, cleaning cloths, protective tapes and other auxiliary materials in strict accordance with the requirements of standard specifications, design drawings and process regulations. For the cleaning of the substrate at the glue injection site, for non-oily pollutants, a mixed solvent of 50% isopropanol and 50% of water is usually used; for oily pollutants, xylene solvent is usually used. The cleaning cloth should be a clean, soft, non-shedding white or natural-color cotton cloth, and the cloth should not be dipped into the container containing the detergent to avoid contamination of the entire solvent. When cleaning, use the "twice wipe" process to clean. After cleaning, the cleaned part must not be in contact with hands or other sources of pollution, otherwise it must be cleaned again. The cleaned substrate must be injected within 15-30 minutes, otherwise, a second cleaning must be performed.

3) Mixing of structural adhesives. The two-component silicone structural glue should be mixed with a special two-component silicone glue maker. When mixing the glue, you should clean the glue maker according to the instructions of the glue maker, adjust the glue nozzle, and then follow the regulations. The mixing ratio is equipped with a two-component sealant for thorough mixing. In order to control the mixing of the structural adhesive, the butterfly sample and the rubber cup pull-off sample should be set aside during each mixing process, check the mixing of the structural adhesive in time, and make a record of the shift. The butterfly test is to check whether the structural glue is fully mixed, and the color of the structural glue is uniform and fully mixed to inject the glue. The butterfly sample number must be recorded during the whole process of mixing.

The glue cup test is used to check the mixing ratio of two-component silicone structural gum base and curing agent.

Injection of structural adhesives. The structural glue must be injected mechanically, and the glue injection should be carried out in order to remove the air in the glue injection gap; the nozzle of the glue injection gun should be inserted into the appropriate depth, so that the glue is continuously, evenly, and fully injected into the glue gap , No air bubbles are allowed; the pressure should be adjusted at the joint to ensure that there is enough silicone structural adhesive. During the glue injection process, pay attention to the color change of the silicone structural glue to judge the change in the mixing ratio of the structural glue. Once the mixing ratio of the structural glue changes, the machine should be shut down and repaired immediately, and the glue at the changed part should be cut off. Fill up with qualified structural glue. After the glue is injected, it should be flattened with a scraper to scrape off the excess structural glue, and the exposed surface should be trimmed to make the surface smooth and without bubbles in the seam. Make a record of glue injection in time for glue injection. The finished glass components after glue injection should be sampled for cutting and peeling test to check the firmness of the bonding and the degree of curing.

How to use silicone structural adhesive

1) One-component silicone structural adhesive can be directly applied to the bonding between aluminum and glass. It is hydrolyzed by absorbing moisture in the air, and the condensation reaction is solidified from the surface to the inside. The glue room is required to be clean and the temperature Not less than 23°C and relative humidity not less than 40%, otherwise it will affect the curing and reduce the strength of the adhesive layer.

2) One-component silicone structural glue is divided into acidic and neutral. When the acidic glue is cured, it will release acetic acid, which will corrode the film layer of the coated glass produced by the vacuum magnetic sputtering method for the hidden frame curtain wall, so it should be used. Neutral silicone structural adhesive.

3) Before using the two-component silicone structural structural adhesive, an accelerator must be added to the base rubber, and the aluminum and glass must be fully mixed and coated in a special glue machine for bonding and curing. Two-component glues are all neutral glues.

4) Silicone structural adhesive has an outstanding feature. That is to say, there is a compatibility problem between the glue and the bonded aluminum, glass, and foam strips. A compatibility test is required. This kind of test cannot be done in China for the time being.

If the compatibility test results show that the structural adhesive is incompatible with one of the three materials, even during the bonding process, all the strength indicators at that time meet the requirements. After half a year or a little longer, the silicone structural adhesive will begin to discolor and change into a liquid state and lose its bonding ability. The glass will fall down, causing serious consequences. Therefore, in order to ensure the long-term bonding ability of the silicone structural adhesive, a compatibility test must be done.