Special Features on Sealant & Adhesives

With its proven-performance in diverse construction uses, Silicon sealant contributes great on commercial buildings' fantastic envelope in modern cities. Why it's silicon sealant not any others? How does it work on mature construction market fields? This page will introduce it briefly.


The architectural appeal of typical commercial buildings is seen in the new projects under-construction that appear in the city skylines. There are more than 60 skyscrapers (height is exceeding 400m) under-building now in China. In China mainland, modern curtain-wall could be defined beginning in 1984, where the concerned project, Sheraton Hotel, locates in Beijing. 30 years history certify modern façade technology as stable & sustainable. Indeed, it proves silicon sealant application on façade as reasonable enough despite suffering diverse loads' attack, against winds, defense rain & snows, daily temperature changes, frozen-thawing year after year.

Silicon Sealant

Why curtain Wall chooses silicon sealant as glue?

We should probe silicon sealant molecular structure in some details. Silicones are mixed inorganic-organic polymers with the chemical formula [R2SiO]n, where R is an organic group such as methyl, ethyl, or phenyl. (Refer to picture4) These materials consist of an inorganic silicon-oxygen backbone (...-Si-O-Si-O-Si-O-.) with organic side groups attached to the silicon atoms, which are four-coordinate.

Sealant Adhesives

Refer to Picture 5 above:
  • The Si-O bond has higher bond energy than the C-O bond.
  • The Si-O bond is longer and flatter than the C-O bond.
  • The Si-O bond has a lower barrier to rotation than the C-O bond and higher free volume.
  • The silicon atom is larger than the carbon atom.
Micro structure determines macro performance. All above points deduce silicon sealant's mechanical properties from its atom structure that ensure silicon sealant attains below mentioned characteristics:
  1. Flexibility.
  2. Outstanding performance.
  3. Resistance to temperature extremes.
  4. Chemical resistance.
  5. Water resistance.
  6. Gas and water vapour permeability.
  7. Durability.
  8. Electrical conductivity.
  9. Thermal conductivity.
  10. Inertness.
Sealants on facade

Why not other sealants on façade, like PU?

Comparing with PU or PS, silicon sealant keeps better performance on resistance to UV exposure, ozone, and extreme temperature. The polyurethane or PS hardens over time and cracks. Chalk, lose adhesion with substrates, often result on water leakage. If above phenomenon happens to façade, it's disaster and fatal on safety or in minimum losts additional repairing cost happens. The primary difference is at the chemical level that Polyurethane is an organic material while silicone is an inorganic material as above mentioned. However if PU is utilized in construction hidden positions, it works well enough representing its valuable properties and key point is not exposed upon long-term sun rays.

Except for difference on UV effectiveness, PU presents plastic characteristics under lower temperature with higher modul while silicon sealant sustains satisfied elastic performance. (See Pic 6 to 7)

Considering what façade suffers actually, silicon sealant could play much more sustainable role whether in structural glazing or weatherproofing. The roughly conclusion is that a polyurethane joint's lifespan is typically 5-10 years, a silicone joint's lifespan is typically 20+ years (combining lab test results and site experiences).

Illustrate one typical job from Joinleader as below (See pic 8) to certify how critical façade works in extreme environments:

Zhoushan Lily Garden

Project Name: Zhoushan Lily Garden

Extreme Environment Conditions

The amazing Lily garden locates in Zhoushan Island of eastern China. The distance from project to ocean is less than 2km linearly. Strong typhoon visits this area plenty of times annually, once the project finished in 2011, the ‘Plum Blossom Typhoon" hit Zhoushan with center speed 35m/sec. Joinsil 998 structural sealant protected façade well as Hercules works.

Critical Requirements:

  1. Salt atmosphere
  2. Typhoon (average 6 times/y)
  3. Rainstorm
  4. Highest standard wind-load in China mainland.

Curtain wall Details:

  • 4-sided, unitized (factory-glazed) construction
  • Sealant bite: 16 mm
  • Site dimensions: 1224 x 1508 mm
  • Windload: 6.79kPa
  • Substrates: 10+12A+10 mm LOW-E glass (SYP); anodized extrusion alum. From Nanshan

Who is Joinleader?

Joinleader® CHINA, one global leading brand in adhesive & sealant market field. Joinleader Silicon Holding Co., Ltd is one manufacturing entity based in Hangzhou near Shanghai. Joinleader global R&D center also locates in Joinleader Silicon Holding Co., Ltd. So, it is much convenient to transfer renovating intelligence to finished products. Joinleader USA, HK, South Africa, Brazil, Mexico and India subsidiaries provide quick-closing Joinleder products & services to domain areas. Joinleader HQ locates in amazing city- Hangzhou, China. Joinleader products are delivered to no less than 100 areas globally including domestic market. Joinleader focuses on construction, automotive, etc markets fields. Annual sales turnover of Joinleader exceeds US$ 75 million. "To leverage up your value" is not slogan but vision.

Facade WP Sealant

Joinleader focuses on silicon sealant makeup and delivery more than 17 years, products range from construction to industry application. (See Table 1)

Joinleader always spends mass resources on R&D to develop suitable silicon products to meet fast-changing market's requirements; customer-driving is key value down-streaming from management board to employee's mindset. As for traditional façade application, Joinleader has supplied niche products to more than 450 projects in market, except for reliable products, professional engineers' expertise also wins façade, fenestration, and IGU manufactures' respect.

Joinleader's output capability is not the largest one even in China, but its professional performance drives Joinleader stepping into Tier I group with well brand image in domestic market. Silicon sealant market was booming from 2003 with China real-estate market's unbelievable growth ratio.

Joinleader's Indian Subsdiary Joinleader Chemtech Pvt Ltd provides product and professional technical support to all Indian customers through their four branches at Mumbai, Bangalore, Chennai, and New Delhi to meet the local requirements. Joinleader India sets its first product centre at New Delhi in 2014.

Martin Chang, and Daneil Wang, Head Product Development and R & D Joinleader HQ at Hangzhou facility.