Curing time and precautions for single component polyurethane sealant

Polyurethane sealant is generally divided into two basic types: single component and two-component. Single component is moisture curing type, and two-component is reaction curing type. Single component sealant is easy to apply, but it cures slowly; Two component has the characteristics of fast curing and good performance, but it needs to be formulated and the process is relatively complex when used. Both have their own development prospects. Polyurethane sealant can be divided into non sagging type and self flowing parallel type according to whether it has fluidity. Non hanging type is used for vertical surfaces, inclined surfaces, ceilings and other occasions, and will not deviate, slide or flow due to the self weight of the adhesive strip before curing; The self leveling type is specifically designed for horizontal situations. According to the properties after use, it can also be divided into non dry type, semi dry type, and fully cured elastic type. Two component polyurethane sealant is not unfamiliar. Polyurethane sealant has excellent performance and low price, and is widely used in joint waterproofing engineering. However, due to the need to mix the two-component polyurethane sealant with the curing agent before use, and to achieve good bonding effect, it must be used within 2 hours after mixing, which brings many inconveniences to the construction. Therefore, single component polyurethane sealant has emerged as a result.
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Precautions for low modulus polyurethane sealant:

1. Not suitable for surfaces of all materials that may leak oil, plasticizers, or solvents.
2. It is not suitable for use in airtight places because polyurethane sealant needs to absorb moisture from the air and solidify.
3. Not suitable for use on frosted or damp surfaces.
4. It should not be used in places that are continuously submerged in water or in places that are humid all year round.
5. Sealing paste should not be applied when the surface temperature of the material is below 4 ℃ or above 40 ℃.
When the temperature is below 5 ℃ or above 50 ℃, construction should not be carried out.
 
Storage period of low modulus polyurethane sealant: Please store in a dry place. Do not open the seal before use. The storage temperature should be below 30 ℃. It is recommended to use it within 9 months after leaving the factory. Shelf life: 12 months. One component polyurethane sealant, named for“ Two component” As for the traditional two-component polyurethane sealant, the kilogram pack should be changed to a single pack. One piece weighs about 750g, and one box contains 20 pieces. When in use, a dedicated glue gun can be used to apply glue, which not only eliminates the tedious process of mixing and mixing sealant, but can also be used at any time. By controlling the opening size of the glue gun nozzle, the glue strip can be better filled in the concrete gaps, saving construction time, reducing waste, and improving construction quality. Single component polyurethane sealant has the characteristics of high elasticity, weather resistance, acid and alkali corrosion resistance, and does not flow when applied on the facade. It is easy to apply and has good adhesion with various substrates such as concrete, metal, and glass. Used for waterproof sealing of joints and expansion joints in stone filling, building construction, road squares, airport runways, bridges and tunnels, and water supply and drainage pipelines. Single component polyurethane sealant has excellent toughness and tensile properties, with a fracture elongation of over 300%.
 
Polyurethane sealant is widely used in industries such as civil engineering, construction, and transportation: its application in the field of construction& mdash; Filling and sealing of doors, windows, glass, etc; Application in Civil Engineering&dash& mdash; Sealing of joints in highways, bridges, airplane runways, etc; Applications in the automotive industry&dash& mdash; Assembly and sealing of car windows (mainly windshield). Sealing glue is a material used to fill gaps (holes, joints, seams, etc.), with both adhesive and sealing functions. Polyurethane sealant, silicone sealant, and polysulfide sealant constitute the three major varieties of advanced sealants currently available. Curing of polyurethane sealant: In cases where a slightly faster curing is required, manually use a serrated scraper to apply the sealant. After applying the sealant, spray water mist on the surface of the sealant. After spraying the water mist, use a scraper to scrape the surface of the sealant once (in order to fully mix the moisture and adhesive). Composite the adhesive, stack the composite board layer by layer, and then apply pressure together. (usually cured in 4-5 hours). The situation where the curing speed needs to be accelerated: manually apply adhesive with a serrated scraper, spray water mist with catalyst on the adhesive surface after coating (after spraying the water mist, the scraper can also be used to scrape the adhesive surface once), and then apply pressure again. For situations where faster curing is required: manually apply adhesive with a serrated scraper, spray water mist with catalyst on the adhesive surface after coating, and then use a scraper to scrape the adhesive surface once after spraying the water mist. The composite adhesive is then sent to a press with a heating device, controlled at 60 ℃, and pressurized for 15 minutes.
 
Main products: various rubber waterstops (steel edge waterstops, external waterstops, intermediate buried waterstops, removable waterstops, etc.), rubber cushion blocks and other rubber products, polyurethane sealants, polysulfide sealants, polyurethane sealants for ballastless track, butyl putty waterstops, butyl steel waterstops, subway waterstops, expansion rubber rings, ST waterstops for pipe galleries, elastic gaskets, elastic cushion under high-speed rail, polyethylene closed cell foam plates, water swelling waterstops, expansion waterstops, one-time grouting pipes, repeatable grouting pipes, GB flexible fillers, anti-seepage covers, PVC mastic and other waterproof materials for construction joints.