MX9708054A - Method for co-refining dry urban wood chips and blends of dry urban wood chips and thermoplastic resins for the production of high quality fiberboard products. - Google Patents

Abstract

A method for making lignocellulose fibers, which may be optionally coated with a suitable thermoplastic, wherein the starting materials may be chosen from a wide variety of generally non-recyclable contaminated wood, paper, and/or plastic products. A mixture of the preferred lignocellulose material characterized by a relatively low moisture content and the desired thermoplastics is refined and comminuted in a steam atmosphere which is at a temperature, pressure, and duration sufficient to soften both the lignin within the wood chips and the thermoplastic polymer. The temperature of the steam atmosphere is relatively high because of the use of dry wood chips which do not result in excessive vaporization during heating. The comminution of the mixture occurs by auguring the mixture between counter-revolving dual refining discs in the elevated temperature, pressurized steam atmosphere. Upon passing through the dual revolving refining discs, the wood chips are continually abraded so as to result in the formation of fine fibers of the lignocellulose material, while the softened thermoplastics are concurrently refined so as to adhere uniformly around each of the abraded lignocellulose fibers. After passing through the refining discs, the fibers are cooled resulting in the formation of uniformly coated lignocellulose fibers, which may be used to form a variety of consolidated fiberboard products, such as by hot pressing or cold pressing operations.