Exploring how high-temperature dry waste materials can produce qualified paper bags

Abstract: This article describes the characteristics of dry waste raw materials and the effect on the chemical structure of wood fibers. The use of high-temperature dried waste materials can produce qualified paper bags.

Key words: drying; masson pine; paper bag paper

In the wood processing industry, the wood utilization rate of plywood factory and match factory is only 30% to 40%, and furniture manufacturing is only 60% to 70%. These companies have a lot of dried scrap to use for pulp and paper. Here to talk about how to make use of the dried wood scraps of match factories and wood processing plants to copy the paper bag paper.

1, raw material characteristics

Uniform, small matchsticks, pressed sheets of plywood, and corners of furniture production. These raw materials are dried at a temperature of 150-200°C.

2. Effect of high temperature drying on the chemical structure of wood fibers

The experimental data in Table 1 indicate that the cellulose fiber, hemicellulose, and lignin are subjected to thermal degradation to a certain degree after the wood fiber raw material is dried at a high temperature. Cellulose is thermally degraded to yellow, the carboxyl and carbonyl content increase, and the solubility in the lye increases. That is, the cold, hot water and 1% NaOH extract content in the table increased. Therefore, the length and strength of the fibers will be reduced.

Experiments also showed that the loss of carbohydrates in the wood fibers after heat treatment is mainly hemicellulose, because hemicellulose is more sensitive to high temperatures than α-cellulose, and is especially decomposed more rapidly during the initial heating. When a large amount of hemicellulose is degraded, it will cause difficulty in beating, the fiber will not easily swell, split, and degenerate, and the resulting paper fibers will have poor interweaving and low strength, which is extremely unfavorable for production of paper sacks requiring high strength. Take the paper bag paper test of dried and undried pine wood stems as an example.

The experimental 15L electric steamer was used to measure the physical strength of the tablet with ZCX-200 at constant temperature and humidity for 2 hours. See Table 2.

As a result of the experiment, the yield, fiber wet weight, and paper strength of the pulp and paper produced from the dried wood were significantly reduced.

3, dry wood in paper bag paper to improve the paper strength measures

3.1 Cooking

Because the cellulose and hemicellulose of wood have been partially degraded after drying, the moisture content of the raw material is low. Therefore, the amount of alkali used during cooking should be low, the ratio of liquid to liquid should be low, the temperature should be raised slowly, and the heat should be kept short to make the steaming even and moderate; the maximum temperature is controlled. 165 °C, to reduce the alkaline degradation of cellulose at high temperatures to stabilize the quality of the brown pulp.

3.2 Beating Three φ450 double disc mills are used in series to beat and gradually feed to make the fibers fully hydrate and swell and reduce fiber cut. The degree of pulping beating 24 ~ 26 ° SR, wet weight ≥ 12g.

3.3 Papermaking

Dry wood pulp should be made with certain proportions of original wood pulp, and press pressure should be increased to increase fiber binding force. Good results have been achieved in production (see Table 3).

From Table 3, it can be seen that when adding 30% dry wood pulp, the impact on the paper forming index is very small. It can be seen that qualified paper bags can be produced with high-temperature dried waste materials. (Wen / Wang Min)