Plastic mesh - definition and characteristics of polypropylene

Polypropylene English name: Polypropylene, referred to as: PP, commonly known as: 100% plastic. Polypropylene is a representative of poly-α-olefin, a thermoplastic resin obtained by polymerizing propylene, and its monomer is propylene CH2=CH-CH3. Depending on the initiator and polymerization process, polypropylene can be classified into isotactic polypropylene and atactic polypropylene and syndiotactic polypropylene. The isotactic polypropylene is easy to form a crystalline state, the crystallinity is as high as 95% or more, and the molecular weight is between 80,000 and 150,000, which gives him good heat resistance and solvent resistance; the random polypropylene is amorphous at room temperature. The micro-band viscous white wax has a low molecular weight of 3,000-10,000, and the structure is irregular and lacks cohesion, and the application is less.
PP is a semi-crystalline material. It is harder and has a higher melting point than PE. Since the PP product homopolymer type has a PP temperature higher than 0 ° C or more, many commercial PP materials are random copolymers of 1 to 4% ethylene or block copolymers of a higher ratio of ethylene. The copolymer type PP material has a low heat distortion temperature (100 ° C), low transparency, low gloss, low rigidity, but has stronger impact strength. The strength of PP increases as the ethylene content increases. The Vicat softening temperature of PP is 150 °C. Due to the high degree of crystallinity, this material has excellent surface stiffness and scratch resistance. There is no environmental stress cracking problem in PP. Typically, PP is modified by the addition of glass fibers, metal additives or thermoplastic rubber. The flow rate of PP has a MFR ranging from 1 to 40. Low MFR PP materials have better impact resistance but lower elongation. For materials of the same MFR, the strength of the copolymer type is higher than that of the homopolymer type. Due to crystallization, the shrinkage rate of PP is quite high, generally 1.8 to 2.5%. And the direction uniformity of shrinkage is much better than materials such as PE-HD. The addition of 30% glass additive can reduce the shrinkage to 0.7%. Both the homopolymer type and the copolymer type PP materials have excellent moisture absorption resistance, acid and alkali corrosion resistance, and solubility resistance. However, it is not resistant to aromatic hydrocarbons such as benzene solvents, chlorinated hydrocarbons (carbon tetrachloride) solvents, and the like. PP does not have oxidation resistance at high temperatures like PE.

Jiuzhi Plastics Network

There are two principal neodymium magnet manufacturing methods:
ï‚·Classical powder metallurgy or sintered magnet process
ï‚·Rapid solidification or bonded magnet process

Bonded NdFeB Magnet is made by evenly mixing neodymium iron boron powder with resin, plastics and low melting point metal and so oncaking agents, then made the boron permanent magnet of compound neodymium iron by methods such as compressing, pushing or injecting shaping. The products take shape once, do not need processing again and can be made into various complicated forms derectly. All directions of the Bonded Ndfeb Magnet are magnetic, and can be processed into compression moulds and injetion moulds.

Bonded Ndfeb Magnets are prepared by melt spinning a thin ribbon of the NdFeB alloy. The ribbon contains randomly oriented Nd2Fe14B nano-scale grains. This ribbon is then pulverized into particles, mixed with a polymer, and either compression- or injection-molded into bonded magnets. Bonded magnets offer less flux intensity than sintered magnets, but can be net-shape formed into intricately shaped parts, as is typical with Halbach arrays or arcs, trapezoids and other shapes and assemblies (e.g. Pot Magnets, Separator Grids, etc.). There are approximately  5,500 tons of Neo bonded magnets produced each year. In addition, it is possible to hot-press the melt spun nanocrystalline particles into fully dense isotropic magnets, and then upset-forge or back-extrude these into high-energy anisotropic magnets.

Bonded magnets can be made from either hard ferrite materials or rare earth magnetic powder. They are manufactured using both injection molding and compression bonding techniques which are fully automated and are particularly suitable for high volume production.
Bonded neo powder is incorporated into numerous end market applications that utilize bonded neo magnets. These products are primarily motors and sensors used in a range of products, including computer and office equipment (e.g., hard disk drives and optical disk drive motors and fax, copier and printer stepper motors), consumer electronics (e.g., personal video recorders and mp3 music players), automotive and industrial applications (e.g., instrument panel motors, seat motors andair bag sensors) and home ventilation systems (e.g., ceiling fans).

Application of Bonded Neodymium magnets:
•Magnetic separators
•Microphone assemblies
•Servo motors
•DC motors (automotive starters) and other motors
•Meters
•Odometer
•Sensors

Bonded Ndfeb Magnet

Bonded Ndfeb Magnet,Permanent Bonded Ndfeb Magnet,Compression Bonded Ndfeb Magnets,Bonded Ndfeb Magnets

Jinyu Magnet (Ningbo) Co., Ltd. , https://www.magnetbonwin.com