Using kenaf pulping waste to mold packaging materials (I)

Abstract: The research on the use of hemp pulp pulp waste liquid and waste hemp core to replace part of urea-formaldehyde rubber and wood shavings pressed particleboard was studied. The modified hemp black liquor and self-made urea-formaldehyde resin are formulated as a particleboard binder in a certain proportion, and the appropriate process conditions are selected to press the hemp and shaving mixture into a sheet having a certain strength and proper density value. The plate can be used as a packaging material to make packaging boxes, trays, and the like.

Keywords: particle board urea formaldehyde resin kenaf black liquor kenaf core packaging material molding

Due to the increasing green trade barriers in international trade and the scarcity of forest resources, the use of wood materials in product packaging is greatly limited. In recent years, wood-based packaging materials have developed rapidly, such as honeycomb paperboard, wood-plastic composite materials, pulp molded products, various fiberboards, and particle board. It is of great significance to reduce the cost of packaging, save wood resources, and maintain ecological balance by using these substitute wood materials for packaging containers, trays, and other packaging containers. The paper industry is an industry with a large amount of waste, but many liquid and solid wastes still have great value in use. In the pulping waste with Kenaf as raw material. The hemp pulping effluent contains available lignin substances, which can be used to prepare the binder for particleboard after being modified; and the waste hemp at the time of preparation: 芑: light weight, has certain compressibility, and can be used instead of Partial shavings produce light particleboard. In this paper, based on the study of the formulation of urea-formaldehyde rubber with modified Kenaf black liquor, through orthogonal test, the impact of the plant's dosage, time and temperature on the main physical properties of the product was analyzed. The process parameters of replacing the shavings pressed chipboard with a ram core portion were explored.

l Experimental method

1.1 Raw materials

1.1.1 Kraft Pulping Waste (KL)

The experimental KI was taken from the light chemical laboratory of the Hong Kong Institute of Light Industry, kenaf kraft pulping waste liquid. Pulp waste liquid composition is quite complex, the main ingredient is lignin and sugar, lignin content of about 30% to 50% of solids, the chemical composition is mainly aromatic polymer compounds, with more Methoxy, hydroxyl, carbon, carboxyl, double bond functional groups, molecular weight of about 9O0 ~ 1 000. Pulping waste liquid as a modified adhesive can be used lignin. After proper concentration, the solid content of the black liquor used in this experiment was 38% to 42%, and the specific gravity was 1.178 g/cm2.

1.1.2 Sawdust and hemp

The wood chips used in the experiment were taken from the pine wood shavings of a construction site and were broken up and used as backup; the hemp core was used to dispose the hemp stem core of the light chemical laboratory of Dalian Light Industry Institute and was crushed to a certain specification for use.

1.1.3 Other experimental drugs

The self-made urea-formaldehyde adhesives include: Urotropine (reagents); Formaldehyde (reagents 36% to 38%); Sodium hydroxide (reagents); Urea; Curing agents: Ammonium chloride, etc.

Preparation of 1.2 KL Modified Black Liquid Urine Acrylic Adhesive

The lignin is first hydroxymethylated, even though formaldehyde reacts with the benzene nucleus in the lignin molecules in the black liquor to produce methylolated lignin. The procedure is as follows: Add KL black liquor to the three-necked flask, add formaldehyde, catalyst (Urotropine), and keep stirring. The reaction temperature was maintained at 95-97°C, the viscosity during the reaction was adjusted by adding a small amount of water, and the modified KL black liquor was prepared by the reaction time of about 2.5 hours. The initial pH of the reaction was 11 and the pH of the product was controlled at 8 to 8.5 at the end of the reaction.

The modified KL black liquor and the self-made urea-formaldehyde rubber were blended and mixed to obtain the KI modified urea-formaldehyde gum.

1.3 Particleboard Manufacturing Method

Mix the sawdust and hemp raw materials in appropriate proportions and make them about 1cm thick by the following operations. Particle board.

The process flow is: mixing the raw materials with a pulverizer, pulverizing, drying, sizing, paving, hot pressing, and demoulding.

Among them, the squeezing and mixing are artificially stirred uniformly; the self-made mold is pressed under the universal testing machine.