Polyether Ether Ketone, PEEK resin (Polyether Ether Ketone, PEEK for short) is a condensation reaction of "difluorobenzophenone" and "hydroquinone" in the presence of alkali metal carbonates, using diphenyl sulfone as the solvent A new type of semi-crystalline aromatic thermoplastic engineering plastic.

Compared with other special engineering plastics, PEEK has more significant advantages, including high temperature resistance of 260 degrees, excellent mechanical properties, good self-lubricating properties, chemical corrosion resistance, flame retardancy, peeling resistance, wear resistance and resistance to strong nitric acid, and radiation resistance. , Super mechanical properties can be used in high-end machinery and aviation and other technologies.

Characteristics of PEEK engineering plastics

High temperature resistance

PEEK has a high glass transition temperature and melting point (334°C), which is one of the reasons why it can be used reliably in applications that require heat resistance. Its load thermal deformation temperature is as high as 316°C, and its continuous use temperature is 260°C.

Mechanical properties

PEEK is a plastic that has a balance of toughness and rigidity. In particular, its excellent fatigue resistance to alternating stress is the most outstanding among all plastics and is comparable to alloy materials.

self-lubricating

PEEK has outstanding sliding properties among all plastics and is suitable for applications that strictly require low friction coefficient and wear resistance. In particular, PEEK modified with a certain proportion of carbon fiber and graphite each has better self-lubricating properties.

Chemical resistance (corrosion resistance)

PEEK has excellent chemical resistance. Among common chemicals, only concentrated sulfuric acid can dissolve or destroy it. Its corrosion resistance is similar to that of nickel steel.

Flame retardancy

PEEK is a very stable polymer. A 1.45mm thick sample can reach the highest flame retardant standard without adding any flame retardant.

Peel resistance

PEEK has good peeling resistance, so it can be made into thinly coated wires or magnet wires and can be used under harsh conditions.

Fatigue resistance

PEEK has the best fatigue resistance among all resins.

Hydrolysis resistance

PEEK and its composite materials are not affected by the chemical effects of water and high-pressure water vapor. Products made of this material can still maintain excellent properties when used continuously in high-temperature and high-pressure water.

PEEK injection molding process flow

1. Drying: Granular polymers generally absorb 0.5%w/w atmospheric moisture. In order to obtain the best results, they should be dried until the moisture is less than 0.02%w/w. The material can be placed in an air circulation oven and dried at least at 150°C for 3 hours, or at 160°C for 2 hours. If dried in a drying box, the thickness of the raw materials in the tray cannot exceed 25mm. and prevent contamination.

2. Recycling: Remaining materials can be recycled and injected into pure materials. It is recommended that recycled materials without fillers should not exceed 30% of the total weight, and recycled mixtures containing fillers should not exceed 10% of the total weight.

3. Thermal stability: If the equipment is shut down during the melting process and the polymer residence time does not exceed 1 hour, there will be no obvious degradation of the material at a temperature of 360°C. However, if the shutdown time exceeds 1 hour, the barrel temperature should be lowered to 340°C. At this temperature, the material can remain stable for several hours. The barrel temperature must be increased when processing continues. If the shutdown time exceeds 3 hours, The barrel should be cleaned. You can use some materials that can maintain stable performance at 380°C, such as polyethersulfone or polyetherimide, or you can use low MFI polyethylene for cleaning.

4. Injection machine: The melting point of the polymer is 343°C. It can be applied to traditional machines that can maintain the melt temperature at 360-400°C.

5. Barrel capacity: Due to the high processing temperatures of PEEK polymer, the residence time of the material must be as short as possible. The ideal barrel capacity is 2-5 times the total shot weight.

6. Nozzle and locking system: The melting point of polymer is very high. If the temperature drops below 343°C, the melt will solidify quickly. Therefore, it is necessary to install a large enough heater at the nozzle to prevent the cooling from causing "injection cold material".

7. Screw: It is recommended that the minimum length-to-diameter ratio L/D of the screw is 16:1, but L/D ratios between 18:1 and 24:1 should be preferred.

8. Barrel temperature: unreinforced grade is 360-380℃, reinforced grade is 380-400℃.

9. Mold temperature: The surface temperature of the mold is 175-205℃.

10. Injection pressure: General injection pressure is 70-140MPa.

11. Injection speed: medium to high speed.

12. Back pressure: It is recommended that the back pressure be set to 0-1.0MPa (0-10 kgf/cm2).

13. Screw speed: Generally, the screw speed is 50-100rpm. For the reinforced grade, it is recommended to use a lower screw speed.

14. Molding shrinkage: Different grades of polymers have different shrinkage rates. The unfilled grade is approximately: 1.2-2.4%, and the filled grade is: 0.1-1.1%.

15. Secondary processing: Secondary processing such as bonding, tapping, pressing, metal inserts, cutting and surface metallization can be performed.