Introduction

Application Overview: PC 2805 is used for industrial accessories, automotive parts, electronic and electrical accessories, UL certified.

Notched impact strength: 85 Oxygen index: 28% Vicat softening point: 144¡æ Heat deformation temperature: 125¡æ

Raw material technical data

Raw material performance and application

Physical properties

PC is a non-crystalline engineering material with particularly good impact strength, thermal stability, gloss, antibacterial properties, flame retardant properties and anti-pollution properties. PC has very high notched Vicat impact strength and low shrinkage, generally 0.1%~0.2%.

Chemical properties

PC has good mechanical properties, but poor flow properties, so the injection molding process of this material is difficult. When choosing the quality of PC material, the final expectations of the product should be used as the benchmark. If the plastic parts require higher impact resistance, then use PC materials with low flow rate; conversely, PC materials with high flow rate can be used, which can optimize the injection molding process.

PC plastic raw materials are a new type of thermoplastic plastics with a transparency of 90%, known as transparent metal. It is rigid and tough, has high impact strength, high dimensional stability and a wide range of operating temperatures, good electrical insulation properties, heat resistance and non-toxicity, and can be molded by injection and extrusion. PC plastics have excellent thermal properties and can be used for a long time between -100¡æ-130¡æ, and the brittle temperature is below -100¡æ.

Although polycarbonate has poor crack resistance and chemical resistance, is easily hydrolyzed at high temperature, has poor compatibility with other resins, and has poor lubrication properties, it can be modified by adding other resins or inorganic fillers to obtain very excellent performance.

Application range

Optical lighting: used to manufacture large lampshades, protective glass, left and right eyepiece barrels of optical instruments, etc., and can also be widely used as transparent materials on aircraft.

Electronic appliances: Polycarbonate is an excellent E (120¡æ) grade insulating material, used to manufacture insulating connectors, coil frames, tube sockets, insulating sleeves, telephone housings and parts, battery shells for miners' lamps, etc. It can also be used to make parts with high dimensional accuracy, such as CDs, telephones, computers, video recorders, telephone exchanges, signal relays and other communication equipment. Polycarbonate thin films are also widely used as capacitors, insulating leather bags, audio tapes, color video tapes, etc.

Mechanical equipment: used to manufacture various gears, racks, worm wheels, worms, bearings, cams, bolts, levers, crankshafts, ratchets, and can also be used as some mechanical parts such as shields, covers and frames.

Medical equipment: can be used for medical purposes, cups, tubes, bottles, dental instruments, medicine containers and surgical instruments, and can even be used as artificial organs such as artificial kidneys and artificial lungs.

Other aspects: used as hollow rib double wall panels, greenhouse glass, etc. in construction; used as textile yarn tubes, textile machine bearings, etc. in the textile industry; used as milk bottles, tableware, toys and models in daily use.

Raw material injection molding process

Injection molding treatment

PC plastic raw materials have a high water absorption rate and must be preheated and dried before processing. Pure PC is dried at 120¡æ, and modified PC is generally dried at 110¡æ for more than 4 hours. The drying time cannot exceed 10 hours. Generally, the air extrusion method can be used to determine whether the drying is sufficient. The proportion of recycled materials can reach 20%. In some cases, 100% of recycled materials can be used, and the actual amount depends on the quality requirements of the product. Recycled materials cannot be mixed with different masterbatches at the same time, otherwise the properties of the finished product will be seriously damaged.

Selection of injection molding machine

PC plastic products are mostly made of modified materials due to cost and other reasons, especially electrical products, and fire resistance must be increased. When molding flame-retardant PC and other plastic alloy products, the requirements for the plasticizing system of the injection molding machine are good mixing and corrosion resistance, which is difficult to achieve with conventional plasticizing screws. When purchasing, it must be stated in advance.

Mold and gate design

The common mold temperature is 80-100¡æ, and the glass fiber is 100-130¡æ. Small products can use needle-shaped gates, and the gate depth should be 70% of the thickest part. Other gates are ring-shaped and rectangular. The larger the gate, the better, in order to reduce defects caused by excessive shearing of the plastic. The depth of the vent hole should be less than 0.03-0.06mm, the flow channel should be as short and round as possible, and the demolding slope is generally about 30¡ä-1.

Melting temperature

The processing temperature can be determined by the air injection method. The general processing temperature of PC plastic is 270-320¡æ, and some modified or low molecular weight PC plastic raw materials are 230-270¡æ.

Injection speed

It is common to use a relatively fast injection speed for molding, such as electrical switch parts. Slow-fast molding is common.

Back pressure

The back pressure of about 10bar can be appropriately reduced if there is no gas mark and color mixing.

Residence time

If the residence time at high temperature is too long, the material will degrade, release CO2, and turn yellow. Do not use LDPE, POM, ABS or PA to clean the barrel. Use PS for cleaning.

Precautions

Some modified PC plastic raw materials are prone to dark brown liquid bubbles due to too many recycling times (molecular weight reduction) or uneven mixing of various components.

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