GB1261136A - Process for the production of chip board - Google Patents

Abstract

1,261,136. Chip board. A. K. HERR, [trading as FASERKUNSTSTOFF-TECHNIK A.K. HERR]. 5 Dec., 1969 [5 Dec., 1968], No. 59564/69. Heading C3N. A process for the production of chip boards having high flame resistance comprises the steps of adding to wood chips a mixture of a fibrous material and pulverulent flame-inhibiting chemicals and then forming the chip boards in known manner. The effect of the association of the fibrous material with the pulverulent flame-inhibiting chemical is to assist in the dispersion of the chemical throughout the finished chip board. The fibrous material may be textile fibres, sawdust, waste materials from the paper industry, grinding dust obtained from chip boards, vegetable fibres, asbestos, glass fibres, and fibre materials obtained by the use of microorganisms, e.g. fungi. The fibre material may have elastic properties and the separate fibres of the fibre material may be ramified, fibrillated or roughened to improve the adhesion thereto of the pulverulent flameinhibiting chemical. To the same end the fibre material may have an electrostatic charge of opposite polarity to the pulverulent flameinhibiting chemical or may enter into an ionexchange reaction with the chemical. The flame-inhibiting chemical may be any conventionally used and of these boric acid is used specifically. Mineral -fillers such as kaolins, talcum and powdered chalk may be included. In a specific example a three-layer chip board is produced in which the two surface layers together make up to 40 parts by weight and the middle layer 60 parts by weight of the total weight. The surface layers, in the compressed state, comprised, by weight, 75À0 parts wood chips, 25À0 parts of a dry fibre mixture consisting of 60% of a dried and ground spilt-over pulp and 40% powdered boric acid, 12À0 parts dry urea resin and 8À0 parts water whilst the middle layer comprised 75À0 parts wood chips, 25À0 parts dry fibre mixture, as above, 8À6 parts dry urea resin and 8À0 parts water. The board was produced by mixing the wood chips and fibre mixture and thereafter spraying in the mica resin as a 48% solution. The finished board has a weight of about 630 kg./m<SP>3</SP>, a bending strength of 215 kp./cm<SP>2</SP>, swelling index of 3À1% and a transverse tensile strength of 3À4 kp./cm<SP>2</SP>.