Note on plastic manufacturing precautions: application of reduced resistance masterbatch in plastic sheet

An extruder requirement: screw diameter: 90-105mm, length to diameter ratio of <33:1, screw: PS.PP special type, a mixing section at the front end, sheet forming pressure 12-14MPa

Two extrusion die: special mold for hanger type extrusion sheet, with automatic screen change system, filter: ? type stainless steel 80 mesh for easy

Stirring of three raw materials: high-speed kneading machine, according to the required surface resistance of the sheet, adding different proportions of the reduced-resistance masterbatch, put into the kneading machine, stirring for 3-10 minutes, if there is a small amount of water, it will be obtained in the process. Eliminate, if too much water, it is recommended to use a dryer or increase the mixing time, high-speed stirring can also remove non-sheet materials that are mixed for unknown reasons, they will be adsorbed on the upper end of the pot due to centrifugal force / electrostatic separation. You can easily remove it.

Four calender rolls: use temperature 60 degrees. Cooling roll temperature is less than 40 degrees; drum pressure: 6 KG/cm 2 or below 6MP. The temperature is too high. If the pressure is too high, the surface resistance will be lost. The residual material between the calender rolls should not be too much, otherwise the pressure orientation will occur, and there will be similar effects of excessive stretching, the longitudinal strength is lowered, and the surface resistance is lowered.

Stretching of five sheets: It has an effect on the surface resistance, and the larger the stretching, the lower the resistance. In particular, hot stretching, that is, the distance between the die exit die and the calender roll is 5?10CM, slightly sagging to unstretched straight to lightly stretched excessively to stretch or stretch excessively; Hot stretching of material - often the surface resistance is reduced, the transverse strength of the sheet is reduced, and the sheet is easily folded/cracked in the lateral direction. If the longitudinal and transverse folding performance is similar, the sheet quality is good for the blister; if both directions are Poor, the quality of the raw materials is poor, and the raw materials/formulations are replaced.

Six raw materials: HIPS raw materials are extrusion grade, common PH88 series 476L 466F 825

The PP raw material is extrusion grade 1300 F401. The melt index is preferably less than 1 g/10 min. The reason is that the hot melt sag is too large to be plasticized.

Recycled raw materials: It can be used in the manufacture of non-food contact blister products. Due to heat aging/degradation, relevant enhancements and toughening auxiliaries can be added to supplement some of the lost properties. BS, SBS and other compatible thermoplastic elastomers can be used as a toughening agent in HIPS; a small amount of aBS can be added to obtain a reinforcing effect, and some organic liquid lubricants can be aged and toughened.

Use of certain incompatible materials: sheet delamination/separation cracking can occur.

Seven static electricity generation / treatment: plastic in the case of high resistance, greater than 10 to the 12th power, there will be static electricity caused by displacement friction, can be up to several thousand volts or even tens of thousands of volts of electrostatic voltage, which hinders production and is prone to occur The source of open flames, especially in the case of flammable gases, is very dangerous and even a fire.

Adding more than 10 parts of the reduced-resistance masterbatch can reduce the surface resistance of the sheet, and 15 parts - 30 can obtain the surface resistance of 10 to 8 in the HIPS sheet, and the static electricity will not be generated under the conductive state, and Permanent, long-term storage / repeated effective!

Ordinary antistatic agent is a time-sensitive additive. It relies on the principle of absorption of anions and cations for more than 3-6 months or repeated heating. The volatile and antistatic effect is gradually lost until it is completely ineffective and dried according to regional characteristics. The role of wet areas varies.

Ordinary sheet production, after the inevitable generation of static electricity, the grounding dissipation can be adopted to increase the indoor/local humidity guide elimination, and the use of the static eliminator is very effective.

Measurement of the surface resistance of eight sheets: At present, the surface resistance tester is often used to test the surface static charge of the sheet. Its range is 10 to 3 to the power of 10, and a better method is to use a high resistance meter.

Recommended ratio of nine anti-resistance masterbatch: 15 parts of surface resistance is added to the HIPS sheet below 8 powers: 30 parts can reach 4 times or less in PP sheet because PP insulation is high and HIPS should be properly added. -40 servings.

Ten other plastic products use: injection molding products. Extrusion tensile products are not suitable for this amount, and if appropriate, the required surface resistance of the product can be obtained.