Raw material for paper making:
1. Calcium carbonate (CaCO3): the average size is 5 m (5/1000mm).
2. Calcium carbonate (CaCO3): the average size is 3 m (3/1000mm).
3. Zinc Stearate industrial skid
4. Magnesium Stearate industrial slippage agent
5. Polyethylene (PE): high density polyethylene, medium density polyethylene or low density polyethylene. Biaxial tensile method requires high density blown film PE, d = 0.95g/cm3, MI = 0.05g/10min.
6. Polypropylene (PP): it can be used for rolling and tape casting.
Contents of each component: 56% ~ 80% of the natural inorganic mineral powder (including calcium carbonate, calcium sulfate, barium sulfate, mica powder, zinc oxide, dolomite fines, calcium silicate, glass fiber, dead hollow glass beads, silica powder, talcum powder, pigment, ferric oxide, silica, bentonite, clay, diatomaceous earth and their mixture, it is after forging burn or without calcine) as the main raw material, with 43%~18% polyethylene(including high density polyethylene, or high density polyethylene with one or more medium density polyethylene, combination of low density polyethylene and linear low density polyethylene) and 1%~2% additives.
Detailed process: (mainly introduction to the first four items)
1.Mix raw materials, auxiliaries, additives and so on in a certain proportion, mix it and measure it into mixer.
2. Modification: the mixing machine disperses the matched materials well. The mixer is generally made of internal mixer (closed mixer, which has high working temperature, high pressure and good mixing effect compared with the open-mixer). The bar material or sheet material obtained by mixing mechanism is not suitable for direct injection into the extruder.
3. Granulation: use the granulator to make strip or plate materials into granulation materials, namely paper materials. The paper material can not only be transported conveniently, but also provide raw materials (for example, different mechanical equipment and processes are required for the production of paper for different purposes) for several parallel production lines, so as to improve the production efficiency of the whole factory.
4. Production: put the paper material into the extruder, the part of the extruder's fuselage will melt the paper material through the screw to produce pressure from the head part to squeeze out the molten paper, and the die head is T mold head, and the tubular material is transformed into the film material flow. The material is extruded by the die head, and the traction equipment is different according to the type of paper produced.
The following are different methods of traction:
The first is the rolling process. That is, through mixing, modification, extrusion, and calendering. The drawback of the calendering process is that the process is complex and is generally used for producing environmentally-friendly paper products of 0.1 mm or more. The product has a large proportion, and the equipment is expensive, but the product has smooth surface, which is suitable for printing advanced samples and book covers.
The second is the casting method. Instead of calender, the tape casting machine can produce various kinds of environmental protection paper with different thickness. However, the distribution of molecular chain in rich mineral paper is unidirectional, so the longitudinal, lateral and physical properties of environmental paper are different, which is a major disadvantage of rich mineral paper.
And then is bidirectional stretching. It is reported that in recent years, Taiwan has introduced "bidirectional stretch pearlite paper". In the process of bidirectional stretching, a small gap will be formed between the base material plastic and the filling material, thus reducing the proportion and cost of rich mineral paper. Because these small gaps refract the light to form the pearlite effect, the production of rich mineral paper has a good appearance, which has been widely used in packaging, printing, advertising and other fields.
After the above traction and stretching methods, the base paper is obtained, and after the post-processing, and then the paper of various uses can be obtained.