Test of Filling Talc Powder in Paper Molding Tableware Slurry

China's talcum powder and calcium carbonate are rich in resources, which can increase the amount of talcum powder added in the production of paper products, which can save a lot of fiber, thereby reducing the cost of paper products. This has been widely used in the paper industry. In order to explore the use of a certain amount of cheap fillers to replace some of the more expensive fiber pulps in the production of pulp molded tableware, we conducted a production test at a paper tableware manufacturing plant based on laboratory tests. The test results are shown in the table below.
From the test results, the test was successful. Its oil resistance, water resistance and strength indexes all meet the requirements. In addition, its smoothness and whiteness are improved.
The feasibility of adding talc in pulp moulding products also lies in the fact that it meets the hygiene standards for food packaging products. According to the characteristics of the mineral filler particles, the following two problems must be solved in the application:
(I) The addition process of the beating system must be changed.

Talc is actually a kind of fine particles with negative charges. In particular, talc, which is preferably wetted with water, exhibits a higher double potential, and its negative charge is comparable to that of china clay. On the other hand, due to the low surface properties of talc, the surface of the talc is hydrophilic and hydrophobic, and the interfacial tension of the gas-solid two-phase interface is less than the interfacial tension of the two phases. Therefore, talcum powder is not easy to get out of the air and is wetted by water, thus affecting its dispersibility, thus restricting its retention on the fiber. According to relevant research data, the retention of fillers, like fibers, is also related to filtration, flocculation and adsorption, but the most significant is the effect of flocculation, followed by filtration. It can be seen that to increase the retention of talc, the surface of talc must be first obtained with good and sufficient lubricity, and its surface charge should be changed so that it can be fully dispersed in the pulp and with the fiber (through retention aids). Complexation occurs and flocculation occurs.
For this reason, if talc is used as a filler and high retention is achieved, attention must be paid to the selection of the addition process and a filler pretreatment system.

Talc powder cannot be added directly to the pulping tank. The filler pretreatment system must be used to make the talcum powder fully dispersed and moistened before it is added so that the talc powder can be complexed with the fiber through the action of chemical additives. The specific process is: processing a stirrer, using an aqueous suspension containing 20-30% of talc filler in a stirrer at high speed for 6 minutes, diluting with water, adding chemical aids, and processing for 5 minutes to prepare a filler suspension , Then add the slurry.
(b) The retention aid must be properly selected and applied.
In some manufacturers, the general additive formulations are only oil-repellent, water-repellent and wet-strength agents. The role of retention aids is often overlooked.
When wood pulp and straw pulp are used as raw materials, retention aids can retain fine fibers, save slurry, save energy, clean white water, and increase the recycling cycle of white water.

Adding fillers in wood pulp and straw pulp, due to the characteristics of such mineral particles, should pay more attention to the selection and application of retention aids. According to experiments, the correct selection and application of retention aids can make talc powder 65-70%, that is, add 20% of talc powder, its utilization rate is 13-14%, and it consumes 1,000 tons of slurry per year. The cost of slurry can be saved by about 400,000 yuan, and the economic benefits are very substantial. If various types of trays are produced, the proportion of additions can also be increased, resulting in greater economic benefits.
The most effective solution for the selection and application of retention aids is:
1. Adoption of retention--enhanced dual system
The addition of talc into the pulp molded product, retention and reinforcement are two key technologies in production, so a binary system consisting of a retention agent and a reinforcing agent can be used. The two auxiliary agents in the dual retention system have been widely used since they have the functions of retention, enhancement, and filter aids.
2. Particles - polymerization system
This system represents the major development of the chemical adjuvant process. The key is that the slurry is added with cation and anion polymers, which can produce a unique, regular and regular flocculation structure. The use effect is greatly improved, which not only improves the water drainage but also improves the retention rate.

Although the use of mineral fillers generally improves the whiteness, smoothness and opacity of paper products, the negative effects must be noted. The use of these mineral fillers increases the surface area of ​​the fiber to be protected, thus weakening the sizing effect, which is its negative effect. Therefore, it is necessary to accurately calculate the relationship between the addition of talcum powder and the increase of the amount of chemical additives through experiments, find out the best matching scheme, and optimize the addition process. We added 20% talcum powder to the factory's production test, and the amount of chemical additives was hardly affected.