How can magnetic plastics improve performance? Come and understand!

Nov 22, 2022

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Magnetic plastic is a kind of polymer material which can record sound, light, electricity and other information and re release functions. It is mainly divided into two types: row configuration and composite type. The so-called structural type refers to the polymer material itself with strong magnetism; Composite type refers to a magnetic body made by mixing magnetic particles with plastic or rubber as adhesive.

At present, structural polymer magnetic materials are still in the exploration stage. Generally, the so-called magnetic plastic refers to the magnetic body with plastic as the adhesive in the composite polymer magnetic materials, commonly known as plastic magnet.

Magnetic plastics are mainly composed of synthetic resin and magnetic powder. The synthetic resin acts as an adhesive. The magnetic powder filled with magnetic plastics is mainly made of ferrite and rare earth materials.

The performance of magnetic powder plastics mainly depends on the magnetic powder materials, of course, it is also closely related to the resin used, the filling rate of magnetic powder and the molding method. The technical indexes for evaluating magnetic plastics include residual magnetic flux density Br. coercivity bHc, intrinsic coercivity iHc and maximum magnetic energy product (B · H) max.

Magnetic plastics are characterized by small density, high strength, strong magnetic retention, and easy to process into parts with high dimensional accuracy and complex thin-wall shapes. They can also be formed with components as a whole, and can also be used for secondary processing such as welding, laminating, and embossing. Its products are small in brittleness, stable in magnetism and easy to assemble. Another advantage is that it is cheap.

On the other hand, the magnetic adsorption force of magnetic plastics is related to the performance of magnetic particles. The stronger the magnetic particle performance, the higher the cost, and the more difficult it is to obtain raw materials. The cost of permanent magnetic materials is 30-80 times that of ordinary materials. In addition, because the materials are extremely easy to oxidize, their surfaces need to be treated, and it is difficult to produce products that are thin (less than 0.5mm) and wide (more than 1000mm). Their ultra-high performance can only be used for injection molding permanent magnets or sintered permanent magnets, It is difficult to be used for ordinary traditional calendered rubber magnets and plastic magnets.

In order to improve the adsorption force and product reliability, many technicians use ordinary pressure-sensitive adhesives to combine with traditional rubber magnets and plastic magnets. Ordinary pressure-sensitive adhesives have poor weather resistance and residual rubber problems, which bring great inconvenience to users. The residual rubber is mainly due to the short molecular chain, small molecular weight and low cohesion of the resin used in pressure-sensitive adhesives. In addition, ordinary pressure-sensitive adhesives are coated on the surface of release film or release paper, It is then bonded to the surface of the magnetic material, so its interlayer adhesion is low, and it contacts the object to be pasted for a long time. Due to the creeping of the molecular chain, it is easy to have glue residue problems, pollution, and damage to the surface of the object to be pasted.