Sealant is a sealing material that guides deformation along with the shape of the sealing surface and is not easy to flow and has a certain cohesiveness. It is an adhesive used to fill the clearance of configurations to play a sealing role. It has the functions of leakage proof, waterproof, vibration proof, sound insulation and heat insulation. Widely used in construction, transportation, electronic instruments and parts of the seal. Due to the wide variety of sealants, strict operation methods, and bad competition in the market, resulting in the poor sealing effect of sealants, the next small series to analyze the phenomenon and causes of unqualified sealants.
1, the phenomenon of
(1) Did not use the neutral structure silicone sealant or the corresponding weatherproof sealant according to the design requirements.
(2) Use structural sealant instead of weatherproof sealant, or a mix of the two.
(3) Can not provide the compatibility test report of structural silicone sealant issued by a specially qualified test and testing organization, only the manufacturer's self-test report.
(4) Structure silicone sealant, weatherproof sealant without durable life warranty, some even more than the service life.
2. Cause analysis
(1) The contractor substituted shoddy products for good ones and used fake and inferior products.
(2) Procurement personnel do not understand the performance of structural sealant and weatherproof sealant, and management personnel lack the necessary regulatory knowledge, resulting in the mixing and misuse of engineering.
(3) Consciously reduce the cost and do not entrust the test according to the prescribed procedures and contents.
3. Governance measures
(1) The glass is fixed to the metal frame, and the expected environmental forces such as wind load, earthquake action, dead weight and temperature change of the glass are transferred to the metal frame through the glue, and the adhesive must adopt the neutral structure silicone sealant. Strength, ductility, bonding performance and other mechanical properties are important indicators to consider, its performance should meet the current national standard "building silicone structural sealant" (GB16776) provisions.
(2) Weatherproof sealant is mainly silicone sealant, chloroprene sealant and polysulfide sealant. The compatibility between them is poor, and it is not suitable to be mixed or used together. Weather resistant sealant is mainly used for external building sealing, atmospheric change resistance, uv resistance, aging resistance is its main consideration index.
(3) The same curtain wall project should use the same brand of single component or two component silicone structural sealant, using the same brand of silicone weatherproof sealant; Structural sealant shall not be used to replace weather-resistant sealant, and shall not be degraded to weather-resistant sealant with expired structural sealant.
(4) The silicone structural sealant must be carefully carried out with the contact material compatibility test and performance testing before the purchase. If there is no such report, the contractor shall urge the contractor to immediately entrust a testing organization with this qualification to carry out special tests (the compatibility test shall use the relevant materials of the project, such as glass, aluminum profile, double-sided adhesive strip, etc.), and the contractor can only use them if qualified.
(5) Silicone structural sealant and silicone weatherproof sealant must be used within the period of validity from the date of entry to the end of curtain wall construction.
(6) Light color, color, transparent silicone structural sealant has poor uv resistance, only applicable to indoor engineering; Outdoor should generally use black.
(7) The storage environment of the glue should meet the requirements of temperature and humidity.