& nbsp; & nbsp; Construction site adhesive manufacturer Jian shares with you the knowledge of using building sealant and precautions for building sealant:< br />
  & nbsp; & nbsp; 1. What are the environmental requirements for the use of silicone sealant in construction< br />
  & nbsp; & nbsp; Due to the curing method of silicone sealant used in construction, the following usage restrictions must be followed when using it:< br />
  & nbsp; & nbsp; . Not suitable for use on building material surfaces that leak oil, plasticizers, or other solvents< br />
  & nbsp; & nbsp; . Not suitable for use on frosted or damp surfaces, airtight or long-term immersion in water< br />
  & nbsp; & nbsp; . Not suitable for use on painted surfaces, as it may cause sealing failure due to cracking or peeling of the paint film< br />
  & nbsp; & nbsp; . Not suitable for surfaces that come into direct contact with food or places that are susceptible to mechanical wear and tear< br />
  & nbsp; & nbsp; . Not suitable for construction at noon or when the surface temperature of building materials is below 4 ℃ or above 40 ℃< br />
  & nbsp; & nbsp;Non structural adhesives are prohibited from being used for structural assembly< br />
  & nbsp; & nbsp; Various adhesives also have their own relative usage limitations, such as:< br />
  & nbsp; & nbsp; Acid glue: Corrosive to copper, brass, and other metals, and not suitable for use with various types of stone and carbide iron matrix materials; Dealcoholization adhesive: not suitable for construction at noon or in direct sunlight, and not suitable for use on fluorocarbon materials< br />
  & nbsp; & nbsp; De loss adhesive: It has a slight corrosion effect on metals such as copper, brass, and silver, and is not suitable for use in the mirror industry.
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  & nbsp; & nbsp; 2. What is the curing method of silicone sealant for construction< br />
  & nbsp; & nbsp; Many consumers are not familiar with the curing method of silicone sealant products used in construction. Silicone sealant for construction is generally divided into single component and two-component according to the curing method; Single component is a process that connects the basic polymer into a three-dimensional skeleton by absorbing moisture from the air and reacting with crosslinking agents. Since it needs to absorb moisture for solidification, it is a process that starts from the surface and goes from shallow to deep, and the deeper it goes, the more difficult it is to absorb moisture and the longer the solidification time will be. Suggest applying glue to a depth not exceeding 5cm< br />
  & nbsp; & nbsp; The two-component mixture is used without relying on other substances for curing and can be deeply cured< br />


  & nbsp; & nbsp; 3. The more expensive the silicone sealant for construction, the better< br />
  & nbsp; & nbsp; Many consumers believe in '; One price, one product; This sentence suggests that the more expensive something is, the better it will be. Actually, it's not like that; The price positioning of silicone sealant for construction mainly depends on its use, and can be basically divided into structural adhesive, weather resistant adhesive, and neutral adhesive. The prices are also arranged in this order. Structural adhesives generally have high requirements for strength and toughness; Weather resistant adhesive has high requirements for high and low temperature resistance, UV resistance, corrosion resistance, and other properties; And neutral adhesive mainly requires glossiness, elasticity, and other requirements. So if tested according to the standards of weather resistant adhesive, it is very likely to be unqualified. (Note: According to national regulations, silicone sealants for buildings other than structural adhesives cannot be used in structural assembly.) Therefore, it is very important for us to choose the appropriate type of silicone sealant according to practical needs when selecting silicone adhesive products< br />


  & nbsp; & nbsp; 4. The faster the curing speed of silicone sealant for construction, the better< br />
  & nbsp; & nbsp; Many construction workers blindly demand that silicone adhesive production companies accelerate curing in pursuit of project schedule or construction speed, which is actually a very wrong approach. The reaction between crosslinking agents and base polymers to form a network like Si-O-Si skeleton structure is a complex process. If the reaction time is too short, it may cause the skeleton structure to be too small, resulting in a lower strength and brittleness of the adhesive after curing; At the same time, it can also lead to incomplete infiltration of the colloid into the substrate, resulting in a decrease in the adhesive strength with the substrate; It is also possible that the small molecule gases generated during the curing process cannot evaporate from the uncured colloid in a timely manner due to the fast curing speed, resulting in the accumulation of bubbles and uneven surface of the adhesive, which affects the appearance; (This type of situation is more common during outdoor construction in summer), if one blindly demands speed, the quality of the project will inevitably be affected. Of course, a slow curing speed can also lead to problems such as contaminating the stone. Therefore, it is recommended that the surface drying time be around 20-50 minutes at room temperature.
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  & nbsp; & nbsp; 5. Can the strength of silicone sealant for construction reach its optimal level within 1-2 days after curing< br />
  & nbsp; & nbsp; We often see many consumers and even construction companies holding just cured glue to test its performance, and some even compare it with glue that has been cured for a few days; Actually, it's also very unscientific. We already know that the cross-linking of silicone sealant for construction into a skeleton structure is a complex and lengthy process. So, silicone sealant for construction can only reach 60% strength after 24 hours of curing, and can reach 75% to 80% strength after 72 hours. To achieve the best strength, acid sealant takes 7-14 days, and neutral sealant takes even longer< br />


  & nbsp; & nbsp; 6. Why does acid glue easily peel off when used on cement and stone< br />
  & nbsp; & nbsp; Acid gel curing produces acetic acid, which reacts with the surface of alkaline materials such as cement and stone, forming a chalky substance that causes detachment< br />


  & nbsp; & nbsp; 7. What is the reason for wrinkling on the surface of neutral adhesive after curing< br />
  & nbsp; & nbsp; The expansion coefficient of the substrate is relatively large, with displacement or vibration; The glue application time is too thin; Catalyst activity is too high, shrinkage is strong, and there are too many plasticizers< br />


  & nbsp; & nbsp; 8. Does the yellowing of neutral transparent adhesive indicate the reason< br />
  & nbsp; & nbsp; The amino groups in crosslinking agents and plasticizers are highly prone to yellowing; If neutral glue and acid glue are used together, it may cause the neutral glue to turn yellow; It may also be caused by the glue being stored for too long< br />


  & nbsp; & nbsp; 9. What is the foaming phenomenon after de alcoholization glue application< br />
  & nbsp; & nbsp; High temperature glue application, high temperature curing< br />
  & nbsp; & nbsp; (1) The curing speed is too fast, and the release rate of methanol is greater than the rate at which methanol seeps out of the colloid, causing the methanol to aggregate and vaporize to produce bubbles. It is recommended to avoid applying glue under direct sunlight (in summer); Avoid applying glue in the morning and curing in the morning and noon. (2) The glue is too thin and should be greater than 6mm< br />
  & nbsp; & nbsp; (3) Foam rod (strip): foam caused by damage (open cell foam strip); There is moisture; Material of foam strip: incompatible, chemical reaction occurs< br />
  & nbsp; & nbsp; (4) The surface dries too quickly and the adhesive solidifies too quickly< br />
  & nbsp; & nbsp; (5) Improper glue application and repeated scraping.
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  & nbsp; & nbsp; 10. Why do some high-end silicone adhesives have poor bonding effects with some aluminum-plastic panels, stainless steel, aluminum alloys, etc., while low-end adhesives stick more firmly< br />
  & nbsp; & nbsp; Because the structural systems of the two are different, high-end adhesives are generally 100% silicone adhesives, which are made of hard materials and lack solubility. They have poor compatibility with general aluminum-plastic panels, stainless steel, and aluminum alloys. In addition, their curing speed is relatively fast, and the surface of aluminum-plastic panels and other materials is flat and smooth. The adhesive has already solidified before fully penetrating the substrate surface, so the bonding is not strong. Low end adhesives have a slower curing speed and longer penetration time. In addition, the addition of plasticizers and other materials makes them soft, making them easily compatible with the substrate and having better adhesion. Therefore, we repeatedly emphasize that customers should conduct self testing before use to observe whether the materials meet the usage requirements. 11) Is aluminum harder to bond in winter than in summer< br />
  & nbsp; & nbsp; In summer, due to the heat absorption on the surface of aluminum materials, the silicone sealant used in construction can quickly infiltrate the substrate and achieve good bonding effect. But in winter, due to the difference in specific heat between aluminum and air, when the temperature changes (especially when moving aluminum from a lower temperature area to a higher temperature area) or due to hand touch, dust, and other reasons, it is extremely easy to form a film layer on the surface of aluminum that is difficult to detect with the naked eye. Due to the presence of this film layer, a membrane appears between the silicone adhesive and the substrate. The inability of silicone adhesive to wet the surface of the substrate greatly reduces its adhesion, and even leads to adhesive failure< br />
  & nbsp; & nbsp; It is recommended that manufacturers place the substrate in the drying room for a certain period of time (such as 24 hours) in winter before construction. At this time, the temperature of the substrate is similar to the indoor temperature, and the temperature of the contact surface between the sealant and the substrate surface is also higher after gluing, which is conducive to the reaction between the coupling agent in the sealant and the functional groups on the substrateIncrease the bonding strength of the sealant.