How to apply silicone sealant under high temperature?

Under high temperature, how can the sealant be properly applied to play its powerful role?

1. What should be paid attention to when using sealant in summer?

The environmental temperature requirements for the use of silicone sealant products are: a clean environment with a temperature of 4°C to 40°C and a relative humidity of 40% to 80%.

In an environment other than the above temperature requirements, it is not recommended for users to apply glue. In addition, the outdoor temperature is higher in summer, especially the aluminum curtain wall, the temperature is higher. If the ambient temperature and humidity are not within the recommended range, it is recommended to conduct a small-area glue test on site and perform a peel-off adhesion test to confirm that the adhesion is good and there are no defects before using it on a large area.

2. How to construct under high temperature?

Construction sequence of structural sealant (structural sealant for curtain wall, secondary structural sealant for hollow, etc.):

1) Clean the substrate

In summer, the temperature is high, and the cleaning solvent is volatile, so attention should be paid to the impact on the cleaning effect.

2) Primer

In summer, the temperature and humidity are high, and the primer is easily hydrolyzed and loses its activity in the air. Attention should be paid to injecting glue as soon as possible after the primer is applied. At the same time, it should be noted that when using the primer, the number and time of the primer contacting the air should be reduced as much as possible, and it is best to use small turnover bottles for separate packaging.

3) Glue injection

After the glue is injected, the weather-resistant sealant cannot be applied on the outside immediately, otherwise, the curing speed of the structural sealant will be seriously reduced.

4) trimming

Trimming should be carried out immediately after the glue injection is completed, which is conducive to the contact between the sealant and the side of the interface.

5) Record and identification

After the above process is completed, it shall be recorded and marked in time.

6) Conservation

Unit elements must be cured under static and unstressed conditions for sufficient time to allow the structural sealant to develop adequate adhesion.

The construction sequence of weather-resistant sealant and door and window sealant:

1) Glue seam preparation

The foam stick on the sealant interface should remain intact. In summer, the temperature is high, and if the foam rod is damaged, it will easily lead to foaming; at the same time, attention should be paid to the compatibility of the substrate and the sealant.

2) Clean the substrate

The glue seam should be cleaned in place to remove dust, oil, etc.

3) Primer (if necessary)

First of all, make sure that the surface of the glue joint substrate is completely dry. In summer, the temperature and humidity are high, and the primer is easily hydrolyzed and loses its activity in the air. Attention should be paid to injecting glue as soon as possible after the primer is applied. At the same time, it should be noted that when using the primer, the number and time of the primer contacting the air should be reduced as much as possible, and it is best to use small turnover bottles for separate packaging.

4) Glue injection

There are many thunderstorms in summer, pay attention to the fact that after the rain, the glue seam should be completely dry before injecting glue.

5) trimming

In summer, the temperature is higher, and the trimming time is shorter than other seasons, and trimming should be done immediately after the glue injection is completed.

6) Conservation

In the initial stage of maintenance, it is not suitable to have a large displacement.

3 FAQ

Short breaking time of structural sealant

Judgment: The breaking time is shorter than the lower limit of the breaking time interval recommended by the manufacturer.

Reason: The temperature and humidity are high in summer, and the breaking time is shortened.

Solution: Adjust the ratio of components A and B within the range recommended by the manufacturer.

Structural sealant primer fails

Reason: The temperature and humidity are high in summer, and the primer solution is easily lost if it is not used properly. Failure of the primer solution will lead to poor bonding of the structural sealant.

Solution: The primer is best used in small bottles, and the unused primer solution in the bottle is not recommended to be used overnight; at the same time, it should be noted that when taking the primer, minimize the number and time of the primer contacting the air ; and check the state of the primer in the bottle in time. If the appearance has changed due to the prolonged storage time, the primer in the bottle is no longer used.

Weatherproof sealant / door and window sealant blistering

Judgment method: There are local protrusions on the surface of the silicone sealant. Cut the cured strip and the inside is hollow.

Reason ①: The surface of the foam rod is punctured during the filling process, and the air is released from the hole after being squeezed;

Solution: Keep the side of the foam rod in contact with the sealant intact. If it is not easy to fill, you can cut a part of the back of the foam rod.

Reason ②: Some substrates react with the sealant;

Solution: Pay attention to the compatibility of different types of sealants and substrates, and a compatibility test is required.

Reason ③: Bubble phenomenon caused by thermal expansion of gas in the sealed glue joint;

The specific reason may be that in the entire closed glue seam, the air sealed in the glue seam after glue injection expands in volume when the temperature is high (generally higher than 15°C), causing blisters on the surface of the uncured sealant .

Solution: Avoid complete sealing as much as possible, and leave a small air outlet if necessary, and fill it up after the sealant is cured.

Reason ④: The interface or accessory materials are wet;

Solution: Do not construct on rainy days, and construct when the weather is fine and the glue joints are dry.

Reason ⑤: construction under outdoor high temperature conditions;

Solution: Suspend construction in outdoor high temperature conditions, and start construction after the temperature drops.

Weatherproof sealant / door and window sealant with short dressing time

Reason: The temperature and humidity are high in summer, and the breaking time is shortened.

Solution: Repair in time after glue injection.