A brief discussion on the glue mixing system in the production of oriented strand board

Abstract: This paper briefly introduces the commonly used adhesives and auxiliary agents as well as the adhesive mixing system in the production of oriented strand board. It also briefly compares the application, advantages and disadvantages of two adhesive mixers used in the production of oriented strand board.

Commonly used adhesives and auxiliary agents for OSB

Glue mixing involves selecting the appropriate adhesive and additives based on the specific board type being produced and adding them in specific proportions according to the corresponding particle flow rate. This process requires appropriate equipment. In recent years, new continuous hot press lines have mostly adopted PMDI with additives, in addition to UF or MUF as the base adhesive. Furthermore, a backup line is reserved, making the glue mixing system extremely complex. Each line (and each additive) requires not only a high-end screw metering pump but also a reliable, highly accurate mass flow metering system. Furthermore, to ensure that failure of the mass flow metering system does not disrupt normal production, a gravimetric metering system is also employed. Currently, there is a gradual shift from simple, intuitive volumetric metering to mass flow meters supplemented by gravimetric metering.

1) The glue mixing process for OSB production is basically the same as that for particleboard production. Adhesive, waterproofing agent, curing agent, process water, etc. are converted into dry matter according to density, volume, solid content or concentration. They are added into the glue mixing tank at the same time according to the proportion required by the process and stirred. After being fully mixed, they are sprayed into the glue mixer by volume measurement.

2) Later, a method of directly measuring the mass of adhesives and various auxiliary agents using weighing sensors appeared, which was called the weight loss method.

3) The adhesive and its auxiliary agents are then measured separately by mass flow meters.

The four glue mixing systems mentioned above for OSB production each have their own advantages and disadvantages. In terms of investment amount, they should be arranged from small to large, which can provide investors with multiple options.

Title: A brief discussion on the adhesive mixing system for oriented strand board production

Authors: Guo Zhiwu, Ge Lijun, Zheng Fengshan

Source: China Wood-Based Panels, Issue 9, 2018