echemi logo
Product
  • Product
  • Supplier
  • Inquiry
    Home > Coatings News > Paints and Coatings Market > What are the applications of sealant adhesives in aerospace instruments?

    What are the applications of sealant adhesives in aerospace instruments?

    • Last Update: 2021-01-22
    • Source: Internet
    • Author: User
    Search more information of high quality chemicals, good prices and reliable suppliers, visit www.echemi.com
    With the development of China's space industry, in order to ensure the normal operation of launch vehicles. Higher requirements are also put forward for the accuracy and sensitivity of space instrument assembly. Effectively preventing the running, risking, dripping and leakage of space instruments, preventing the leakage of internal media, and the intrusion of external media are the most basic conditions to ensure the high precision, high sensitivity and high reliability of

    .
    Space instrument according to the different requirements of use, structural forms can be diverse, in many parts, due to the use of aluminum alloy, stainless steel, engineering plastic and quartz glass and other special materials, not suitable for welding, riveting, screwing and other connection methods, and some structural miniaturization requirements, not suitable for the use of solid seals, must use sealant adhesive for the glue installation of components. Because these materials, structural components using liquid sealant adhesive components for the fitting of components is the most convenient, effective and reliable.
    , polysulfur rubber sealantPolysulfur rubber sealant is a sealant adhesive based on liquid polysulfur rubber. Polysulfur rubber is a rubber-like polysulfur vinyl resin. In fact, it is a substance located between synthetic rubber and thermoplastics. It can be produced by a shrinking reaction between DCH and sodium tetrasulphide, which is as follows:
    nClCH2-CH2Cl- nNaS4Na-→ (CH2-CH2-S4) - 2nNaCl
    the molecular chain of polysulfur rubber is saturated and contains sulfur atoms, so it is oil-resistant, curvature-resistant, impact-resistant, and low-temperature.polysulfur rubber is generally a dark amber or dark brown thick viscous liquid with an average molecular weight of between 1000 and 5000. The average sub-volume is 1000, mainly used as epoxy resin and phenolic resin toughener. The average molecular weight of 4000 is usually used as a base for polysulfur sealants alone. Liquid polysulfur rubber has an active reaction group sulfur alcohol base on the molecular chain, which can react with a variety of metal peroxides, organic peroxides and some oxidants. When a metal peroxide curing agent is added, it can be cured into an elastomer in warmth, room temperature, low temperature and oil medium. The most widely used and most commonly used are lead dioxide and active manganese dioxide, which react as follows:
    HS-R-SH- PbO2-→ (RSS)n-PbO-H20
    HSR-R-SH-PbO-→ (R) SPbSR) - H20
    -RSPBSR - Pb02 - → (RSS) n - PbO - H20
    Because of the oil- and elastomer properties of cured polysulfur rubber, we use it as a sealant adhesive for angular speedometer sage assembly. The external structure of the angle velometer stator is: the stator base material is stainless steel, the surface is gilded, with glass insulators, filling tsui, resistance elements, tuning screws and other components, the internal medium is silicone oil. In order to prevent internal liquid leakage, the adhesive is required to have the characteristics of silicone oil, shock-proof, shock-absorbing and so on, the use of polysulfur sealant for glue is more appropriate.
    , polyurethane sealant adhesive
    polyurethane sealant is a kind of elastic sealant adhesive based on polyurethane rubber. Polyurethane rubber is a special kind of rubber, it is actually a kind of polymer compound between the general rubber and plastic.of polyurethane elastic sealant is that the surface hardness is high, elastic, and has excellent cold resistance, oil resistance. Its bonding strength at low temperatures is even higher than that at room temperature. If the raw material components and ratio is changed, it can obtain an excellent elastomer with a hardness of 20 to 80, an elastic mod of 50 to 6000 kg/cm, and a wide range of sheet strength of 50 to 80 kg/cm. With such excellent performance, there is currently no more suitable elastomer that may replace it.
    , silicone rubber-type elastic sealant
    silicone rubber-type eglia sealant substation is high molecular weight of line-type polysilicae. Its molecular primary bonds are alternating between silicon and oxygen atoms.
    Because the bonds of silicon oxygen bonds can be much higher than the carbon bonds of other polymer compound molecules, it is highly heat and cold resistant, and can maintain good elasticity in the temperature range of -65 to 250 degrees C. In addition, it does not contain double bonds on the molecular side keys, so it has excellent aging resistance, the effect on ultraviolet rays, ozone is very stable. After ten years of atmospheric aging and three years of artificial accelerated aging, it still does not occur cracking, brittleness and peeling and other aging phenomena.
    , anaerobic sealant adhesive (hereinafter referred to as anaerobic adhesive)
    anaerobic adhesive substrate is thermosteroid resin, most of which are currently propylene thinnestate type. The outstanding properties of anaerobic adhesive are pressure-resistant and vibration-resistant. It is used in the joint part of the hydraulic system to withstand high pressure of 300kg/cm2. Spring washers and other fastening seals can be saved for some binding sites that have long been subjected to various external forces. It also has a better fastening effect than spring washers. In addition, anaerobic glue also has a single group, solvent-free, room temperature curing and low viscosity and other advantages.the sealing effect of anaerobic gel mainly depends on it curing crosslinking under isolated oxygen. At present, most of the substrates of anaerobic gum belong to acrylic type. Its substrate is dominated by methyl acrylates or acrylic duoesters and their derivatives.
    anaerobic glue has been widely used in the instrumentation industry, machinery industry, automotive industry, a better solution to the product three leakage (leakage, oil leakage, gas leakage) technical problems. It plays an important role in product decoration, quality assurance, energy conservation, cost reduction and economic efficiency.
    5, epoxy sealant adhesive
    liquid sealants with epoxy resin as sealant substates have been widely used in various production areas, because epoxy resin has the following unique advantages: 1. Strong bonding force: epoxy resin molecules The polar groups of fat hydroxyl and ether chains in the structure produce electromagnetic gravity between epoxy resin and adjacent interface, and epoxy base can generate chemical bonds with metal reactions containing active hydrogen, so it has good adhesion to metals, glass, plastics, ceramics and other materials.2. Small shrinkage: it is not produced by by-products in the curing process, and no bubbles are generated from it. For pure resin curing, its shrinkage rate is less than 2%, after adding fillers can be reduced to about 1%.3. Good stability: long-term storage and constant quality 4. Good media resistance: resistance to general acid and alkali and organic solventslow creep: in long-term force conditions, no deformation or deformation is very smallprocess is good: choose different curing agents and add other resins, rubber and fillers to achieve change, can make epoxy resin at room temperature or low temperature conditions curing, can also be fast solidification. Epoxy resin varieties are many, curing agent varieties are not less than dozens of species, as a preparation of sealant adhesives are generally with low molecular weight BPA epoxy resin plus tougheners and can be medium temperature or room temperature curing curing agent preparation.
    This article is an English version of an article which is originally in the Chinese language on echemi.com and is provided for information purposes only. This website makes no representation or warranty of any kind, either expressed or implied, as to the accuracy, completeness ownership or reliability of the article or any translations thereof. If you have any concerns or complaints relating to the article, please send an email, providing a detailed description of the concern or complaint, to service@echemi.com. A staff member will contact you within 5 working days. Once verified, infringing content will be removed immediately.

    Contact Us

    The source of this page with content of products and services is from Internet, which doesn't represent ECHEMI's opinion. If you have any queries, please write to service@echemi.com. It will be replied within 5 days.

    Moreover, if you find any instances of plagiarism from the page, please send email to service@echemi.com with relevant evidence.