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What are the applications of sealing adhesives in aerospace instruments (3)?

Update:26-04-2022
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What are the applications of sealing adhesives in aeros […]

What are the applications of sealing adhesives in aerospace instruments (3)?

4. Anaerobic sealing adhesive (hereinafter referred to as anaerobic adhesive)

The matrix of anaerobic adhesive is thermosetting resin, most of which are acrylate type at present. The outstanding properties of anaerobic adhesive are pressure resistance and vibration resistance. It is used in the joint part of the hydraulic system and can withstand high pressure of 300kg/cm2. Spring washers and other fastening seals can be saved for some joint parts that are used for a long time to bear various external forces. And has a better tightening effect than a spring washer. In addition, anaerobic adhesive also has the advantages of one component, no solvent, room temperature curing and low viscosity.

The sealing effect of anaerobic adhesive is mainly achieved by curing and cross-linking under the isolation of oxygen. At present, the matrix of anaerobic adhesive is mostly acrylate type. Its matrix is ​​based on methacrylate diester or acrylate diester and their derivatives.

Anaerobic adhesive has been widely used in the instrument industry, machinery industry, and automobile industry, and it has solved the technical problems of three leakages (water leakage, oil leakage, and air leakage) of products. It plays an important role in product decoration, quality assurance, energy saving, cost reduction and economic benefit improvement.

Five, epoxy resin sealant

Liquid sealants using epoxy resins as sealant binders have been widely used in various production fields because epoxy resins have the following unique advantages:

1. Strong adhesion: the polar groups such as aliphatic hydroxyl groups and ether chains in the molecular structure of epoxy resins generate electromagnetic attraction between epoxy resins and adjacent interfaces, and epoxy groups can react with metals containing active hydrogen Generate chemical bonds, so it has good adhesion to metals, glass, plastics, ceramics and other materials.

2. Small shrinkage: it has no by-products during the curing process, and no bubbles will be generated. For the cured product of pure resin, the shrinkage rate is less than 2%, which can be reduced to about 1% after adding filler.

3. Good stability: can be stored for a long time without deterioration

4. Good medium resistance: can withstand general acid and alkali and organic solvents

5. Low creep: no deformation or minimal deformation under long-term stress

6. Good manufacturability: Select different curing agents and add other resins, rubbers and fillers to achieve modification, so that epoxy resin can be cured at room temperature or low temperature, and can also be cured quickly.

There are many types of epoxy resins, and there are dozens of types of curing agents. As a sealing adhesive, low molecular weight bisphenol A epoxy resin is generally formulated with a toughening agent and a curing agent that can be cured at medium or room temperature.

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