Silicone glue, MS glue, polyurethane glue, which one is better
As my country accelerates the industrial upgrading of the construction industry, prefabricated buildings have shown rapid development in recent years. Prefabricated building sealants are used as exterior wall panels Seam waterproofing is the first line of defense. Its performance is directly related to the waterproofing effect of the project, and it has attracted more and more attention. Currently, there are many manufacturers of construction sealants on the market, with various types. They can be roughly divided into : Silicone glue (SR), polyurethane glue (PU), silane modified polyether glue (SMP, also called MS glue abroad).
Types and characteristics of prefabricated building sealants commonly used on the market
Silicone glue (SR) is a sealant prepared from polydimethoxysiloxane as the main raw material. This sealant has excellent elasticity and good weather resistance, but it also has some defects, such as poor paintability.
Silicone glue (SR) is a sealant prepared from polydimethoxysiloxane as the main raw material. This sealant has excellent elasticity and good weather resistance, but it also has some defects, such as poor paintability.
Polyurethane glue (PU) is based on polyurethane pre-formed glue Polymer is the main component. This type of sealant has high tensile strength and excellent elasticity, but has poor weather resistance, alkali resistance, and water resistance. It cannot resist heat for a long time and the storage stability of single-component glue is greatly affected by the outside world. Bubbles and cracks may occur when used in high temperature environments.
Silane modified polyether sealant (SMP ) is a sealant prepared with silyl-terminated polyether as the base polymer. This type of product has excellent elasticity, low pollution and other characteristics, and has good bonding effect with concrete slabs, stone and other building materials.
Performance requirements and selection of prefabricated building sealants
Prefabricated building exterior wall panels are located on the building facade and are directly exposed to the atmospheric environment. Various factors including temperature, humidity, building load, earthquake load, sunlight exposure, etc. will affect its performance. This requires sealant for prefabricated buildings. There should be many requirements, and the overall performance should be strong. The main performance requirements are as follows:
Prefabricated building exterior wall panels are located on the building facade and are directly exposed to the atmospheric environment. Various factors including temperature, humidity, building load, earthquake load, sunlight exposure, etc. will affect its performance. This requires sealant for prefabricated buildings. There should be many requirements, and the overall performance should be strong. The main performance requirements are as follows:
1 Mechanical properties
Prefabricated exterior wall panels will undergo relative displacements under the action of load, temperature, etc., so the sealant used in prefabricated buildings must have a certain degree of elasticity, a certain degree of free expansion and deformation, and excellent recovery ability. The mechanical properties of sealant for prefabricated buildings should include displacement capacity, elastic recovery rate, tensile modulus, elongation at break and other indicators.
Prefabricated exterior wall panels will undergo relative displacements under the action of load, temperature, etc., so the sealant used in prefabricated buildings must have a certain degree of elasticity, a certain degree of free expansion and deformation, and excellent recovery ability. The mechanical properties of sealant for prefabricated buildings should include displacement capacity, elastic recovery rate, tensile modulus, elongation at break and other indicators.
2 Weather resistance
JGJ1-2014 “Technical Regulations for Prefabricated Concrete Structures” clearly stipulates that weather-resistant materials should be used as waterproof sealing materials for building joints. If the materials are improperly selected, it will affect the sealing performance and lifespan of prefabricated buildings, causing the sealant to crack. This can cause water leakage, which may even lead to sealant failure soon after assembly, affecting the safety of the building.
JGJ1-2014 “Technical Regulations for Prefabricated Concrete Structures” clearly stipulates that weather-resistant materials should be used as waterproof sealing materials for building joints. If the materials are improperly selected, it will affect the sealing performance and lifespan of prefabricated buildings, causing the sealant to crack. This can cause water leakage, which may even lead to sealant failure soon after assembly, affecting the safety of the building.
Contains a large amount of C-N in the main chain of polyurethane glue Bond, compared with silicone glue and modified polyether glue, its bond energy is the lowest. Under long-term sunlight exposure, the C-N bonds in the molecular chain of polyurethane glue are prone to chain scission, resulting in powdering and cracking. This is the main reason why the weather resistance of polyurethane glue is not as good as that of silicone glue and modified polyether glue.
3 Environmental protection
Green environmental protection is the need for economic and social development. The editor tested the TVOC of PU, SR, and MS sealants in accordance with GB18583. The test results showed that the TVOC of PU glue was 80 mg/L, while the TVOC of SR and MS were both lower than the equipment detection limit. value (50mg/L), the environmental protection is obviously better than PU glue.
Green environmental protection is the need for economic and social development. The editor tested the TVOC of PU, SR, and MS sealants in accordance with GB18583. The test results showed that the TVOC of PU glue was 80 mg/L, while the TVOC of SR and MS were both lower than the equipment detection limit. value (50mg/L), the environmental protection is obviously better than PU glue.
In addition to volatile components, PU glue also contains A certain amount of free isocyanate is harmful to people. Some people feel dizziness, headache, nausea, and shortness of breath. Some people even vomit blood immediately after smelling this smell. In severe cases, they may faint immediately; it can Accumulation in the human body and long-term exposure to high-concentration gas environments will cause damage to the skin and mucous membranes, poison the central nervous system, cause visceral dysfunction and even poisoning, and have potential carcinogenic effects. Pay attention to maintaining good ventilation and taking necessary protective measures when using it.
4 Finishability
In this article, water-based waterproof latex paint is applied to the surface of the cured sealant. The results are shown in Figure 1.
In this article, water-based waterproof latex paint is applied to the surface of the cured sealant. The results are shown in Figure 1.
You can find PU glue and SMP from Figure 1 Glue can form a smooth and uniform paint film with good finishability; while SR glue has low surface energy, the latex paint will shrink and cannot form a uniform paint film, and the finishability is poor.
5 Cure Rate
This article tested the 24h curing thickness and 15d curing thickness. The results are shown in Table 4.
This article tested the 24h curing thickness and 15d curing thickness. The results are shown in Table 4.
PU glue, SR glue and SMP glue are all It needs to absorb moisture in the air and gradually react and solidify from the surface to the inside. The cured thickness of PU glue is 2-3mm in 24 hours and 15-17mm in 15 days; the cured thickness of SR glue is 2-3mm in 24 hours and the cured thickness in 15 days. 20-22mm; Baiyun brand single-component SMP has strong reactivity, the curing thickness is 4-5mm in 24h, and the curing thickness in 15d is 28-30mm. When Baiyun brand single-part and double-part SMP is cured, it reacts with the moisture in its own system, both internally and externally, and can be completely cured within 24 hours.
As can be seen from the above performance, it is similar to polyurethane Glue, silane-modified polyether glue and silicone sealant have good adhesion, excellent mechanical properties and weather resistance, and good overall performance. They can provide reliable waterproof sealing solutions for prefabricated buildings and ensure the safety of prefabricated buildings. Safety and service life. However, it should be noted that silicone sealant cannot be used for joint sealing of prefabricated buildings with coating requirements.
Waterproof latex paint is applied to the surface of the cured sealant. The result is shown in Figure 1.
