How to choose the right construction sealant？

With the continuous updating of building construction technology, there are more and more choices of sealants. Among them, it is particularly important to correctly select professional and targeted building sealants and control their construction quality!

There are many types of building sealants: including silicone, polyurethane, polysulfide, acrylic, butyl, asphalt and oily resin modified products, etc.

At present, the building sealants used in my country are mainly three room temperature curing elastic sealants: silicone, polysulfide, and polyurethane, and the most widely used is silicone sealant.

Selection of building sealants:

How to choose sealant is the key. The selection of building sealant is mainly based on its performance characteristics, as follows:

1. Concrete bonding

Most of the PC boards used on the market are concrete boards, so the building sealant should have good adhesion to concrete. When choosing a building sealant, you should consider whether concrete is an alkaline porous material and whether the release agent used during demoulding remains on the surface of the PC board.

2.Seam displacement

When choosing a sealant, its mechanical properties are also important. The displacement of the joint should be considered during design and the width of the joint should be determined so that the deformation of the sealant is within the maximum allowable range. Sealants are generally required to have good displacement capabilities and elastic recovery rates to adapt to joint displacement.

3. Weather resistance

The weather resistance of building sealants will affect their service life. Due to the specific molecular structure of silicone sealants, even the highest energy ultraviolet rays are not enough to damage its structure, ensuring that silicone sealants have good UV resistance. , giving it obvious advantages in weather resistance.

Construction technology of building sealant:

1. Pre-construction test

Construction sealants should undergo bonding performance tests and compatibility tests before construction to avoid delays in construction and waste of materials and labor due to sealant tapping and rework after construction.

2. Construction preparation

Preparation work → press the metal shrapnel and pull the metal rod → cut the soft sealant → inject sealant and bond → put the cut sealant into the sealant bucket → put the sealant nozzle and tighten the front cover → apply sealant.

3. Frequently Asked Questions

(1) Not bonded to the base material

The main reasons are that no adhesion test was conducted before construction, the curing temperature was too low, and the relative humidity was too high. During construction, the curing temperature should be increased, the curing time should be extended, the base material should be surface treated or the sealant should be replaced.

(2)Slow curing speed

The main reasons are low ambient temperature and low humidity, the sealant gap is too narrow and too deep, the sealant has expired, etc. During construction, the curing temperature and humidity should be increased, sealant should be applied twice or on both sides, and the sealant should be replaced.

(3) Bubbles are generated

The main reasons are that air enters during sealant injection, moisture intrudes into the sealant joints, the base material reacts with certain sealants, etc. During construction, the sealant should be injected evenly, continuously, and the interface should be filled, and the interface and accessory materials must be dry.

(4) Drumming

The main reasons are that the large size of the plate and the large expansion coefficient lead to joint deformation, the large temperature difference between day and night in the plate, and the low ambient humidity. During construction, a sealant with a relatively fast curing speed should be used, and appropriate shading measures should be used to reduce the panel temperature.

(5)Cracking and leaking

The main reasons are that the joints are too narrow, the sealing is not in place, the sealant has insufficient displacement capacity, and the sealant thickness is too thin. During construction, joints should be designed according to specification requirements, sealants with good displacement capabilities should be selected, and construction should be carried out according to operating specifications to ensure the thickness of the sealant and avoid three-sided bonding.