How to Choose the Right Construction Adhesive or Sealant

Silicone structural sealants are increasingly used in construction. Most are named for their intended applications, so select a product according to the joint where it will be used. Where a joint must carry mechanical loads, a structural sealant is required. By contrast, a weatherproof sealant is intended to keep out air and water, not to carry structural loads. Put simply, a structural sealant carries the load, while a weatherproof sealant seals the joint. In certain applications, a structural sealant can be used where a weatherproof sealant would otherwise be specified, but a weatherproof sealant must never replace a structural sealant.

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Structural glazing applications

The sealant between curtain wall panels and their supporting structure must withstand a range of loads and maintain long-term adhesion without detaching. It must meet the requirements of China’s mandatory standard “Silicone Structural Sealant for Construction” (GB 16776). High-rise and supertall buildings, large-panel glass curtain walls, systems using laminated insulating glass, and curtain walls in seismic intensity 9 regions—and combinations of these conditions—require high-performance silicone structural sealants. Their high tensile strength and elongation at break allow them to withstand greater loads at the same bonding width.

Glorystar Chemicals N30

Glorystar Chemicals A18

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Building curtain panel joints

Expansion joints between curtain wall panels must be filled with sealant. Weather-resistant silicone sealant is used for this purpose. It must accommodate movement caused by wind and dynamic loads, as well as thermal expansion and contraction of the substrate. The bond must remain intact under tension and compression, with good elastic recovery so the joint returns to its original shape when movement stops.

Glorystar Chemicals N33

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Stone panel parts

Stone cladding requires a dedicated silicone sealant. Stone is porous and can be difficult to clean once stained. Conventional sealants may contain non-reactive, low-molecular-weight ingredients such as plasticisers, which can migrate into the stone. This can leave oily marks on the surface, attract dust and discolour the stone. There are two types of products for stone: joint sealants for gaps between stone panels, and adhesives for fixing dry-hung stone to metal anchors. Rigid epoxy resin adhesives were commonly used for dry-hung stone in the past, but building vibrations can transfer stress to the panels and cause them to crack. .

Glorystar Chemicals N35

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Skylight roof applications

Skylight roofs experience significant and complex movement caused by their own weight, snow and wind loads, asymmetric loads, and thermal expansion and contraction. This includes both horizontal and shear movement. Polycarbonate panels have a thermal expansion coefficient six to seven times that of glass, so the sealant must have a low modulus, accommodate substantial joint movement, and adapt well to the substrate. A 50LM low-modulus silicone sealant with ±50% movement capability is recommended. The sealant should also be clear and provide an attractive finish.

Glorystar Chemicals N38

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Door and window joints

The gap between the aluminum alloy and the glass of colored aluminum alloy doors and windows should be filled with room temperature curing sealant. After the sealant has fully cured, the glass and aluminum alloy form a solid body. In the past, polyacrylate, neoprene, polyurethane, etc. were used for filling, and either the bond was easily damaged by external force or harmful gases were emitted. Silicone sealant does not have such disadvantages and can provide long-term sealing and waterproofing.

Glorystar Chemicals D38

Glorystar Chemicals D28

Source: China Curtain Wall Network

About Glorystar Chemicals:

Guangzhou Glorystar Chemicals Co., Ltd. was established in June 1996 with a registered capital of 11 million yuan. It mainly produces high-quality silicone sealant (one of the drafting units of the national standard GB16776 “Silicone Structural Sealant for Construction” and “National Standard Silicone Construction Sealant” GB/T14683) and modified starch powder (industry standard “Plastic Putty Additive for Interior Decoration” JC/T 2316-2015), it is one of the few “certified enterprises for the production of silicone structural sealants for construction” in China and the largest and only modified starch powder manufacturer certified by four national ministries and commissions. It is also a national high-tech enterprise, a key high-tech enterprise in the National Torch Plan, and a national outstanding private technology enterprise.