Overview of a-cyanoacrylate adhesive (middle)

In view of the above-mentioned advantages and disadvantages, cyanoacrylate adhesives can be used for bonding equipment, instrument parts, bonded strain gauges, arts and crafts, glue vulcanized rubber seals and sashes, temporary processing fixed, positioning, machine repair, The repair of utensils and other aspects. Absorption adhesives are used abroad for sand mould manufacture (for metal casting) and have a tensile strength of 2.76 MPa.

In addition, high-purity a-cyanoacrylate is basically non-toxic to human body, and the a-cyanobutyl acrylate adhesive sterilized by high temperature 120-150° C. is greatly developed on the basis of animal experiments, such as Wound closure, ophthalmic surgery tissue cementation, organ transplantation, surgical reshaping, and evasion prevention.

The rapid curing and easy use of a-cyanoacrylate has brought a lot of benefits to home users, so it is increasingly accepted as a household adhesive.

5. Application process

When a-cyanoacrylate is used for bonding, the material gap is required to be between 0.01-0.08 mm. If it is 0.2 mm or more. Need to add tackifier, otherwise it will extend the curing time and reduce the bonding strength.

The surface of the adherend is generally wiped with an organic solvent such as acetone to remove grease or release agent. It should be noted that the presence of a salt-based substance on the treated surface accelerates the curing of the adhesive, and the presence of an acidic substance can cause a slow curing rate and must be thoroughly cleaned.

The higher the polarity of a-cyanoacrylate, the higher the adhesive strength of the material. In general, the strength of bonded metal is highest; neutral glass and rubber tend to damage the material itself, while the glue layer remains intact; the glued plastic is inferior to metal and rubber. The bonding strength of dissimilar materials is greater than that of the same material. Based on this, in order to solve the problem of instant dry rubber problems, metal and rubber are often glued or intermetallic lining with a rubber layer.

For difficult-to-stick materials such as polyethylene, polypropylene, Polyethylene, etc. must be pre-treated with special treatment. When coating, if the shape and material of the two adherends are the same, only one adhesive surface needs to be coated. If they are different, the adhesive surface on the upward, the surface with the smaller surface, the surface with slow curing, or the difficulty Penetration of one side of the coating, coating amount of 5mg/cm is appropriate.

After the glue is applied, the two adhesive joints are accurately attached, and no pressurization is required. Only the two adhesive joints can be in close contact with each other. Although a-cyanoacrylate can reach its maximum strength within 30 minutes, it will take several hours for the reaction to end or the cementing and anchoring to be completely thorough. Therefore, it takes several hours to one day for the adhesive to be attached. When the wood is glued, the maximum bonding strength can be achieved within 2 to 8 minutes.

After the glue is applied, the two glue joints should be attached immediately, and the tensile strength of the glue is drastically decreased over 30 seconds ^-50 seconds. Operating environment: The humidity is 50-60% and the temperature is 15-350C. If the temperature is 70-100°C, the strength can be increased by 15%.

In general, the curing of a-cyanoacrylates is sensitive to various substrates, especially acidic surfaces that retard or slow negative ion cure. Surfaces are often treated with various alkaline surfactants such as dimethylformamide to overcome this.

In general, glass and rubber have the fastest adhesion speed, followed by plastics and metals. However, the adhesion speed to the living body, especially human skin, is faster. This is because the skin contains amino acids that promote the curing of the adhesive. Be careful not to let the glue come into contact with the skin during operation. Commonly used surface treatments (or primers) improve cure speed.

The special function of cyanoacrylate reacts rapidly with amino acids, enabling people to use their volatility to track the fingerprints of the perpetrators to help the reconnaissance officers detect and detect crimes.