SU1722835A1 - Process for manufacturing wood chip boards with thermoplastic binder - Google Patents

Abstract

The invention relates to the woodworking industry and can be used in the manufacture of wood-based panels on a thermoplastic binder. The purpose of the invention is to reduce binder consumption. To this end, softwood chips of fractional composition 5/1 with moisture of 5-7% are mixed in a paddle mixer with a thermoplastic binder. The thermoplastic binder is prepared as follows. A mixture of thermoplastic with low density polyethylene is preliminarily prepared at a ratio of them, wt%: 30: 70-70: 30. Then, the resulting mixture is subjected to elastic-deformation grinding in a twin-screw extruder in a known manner to a powder with parameters: bulk density - 150-220 kg / m3; particle size - not more than 2.5 mm. Thermoplastic binder powder with a bulk weight of less than 150 kg / mt was not possible to obtain a fibrous structure. The pressing of plates is carried out on a laboratory press at 443-5453 Kc, followed by cooling the plates under pressure to 333 K. The pressing pressure is 2.5 MPa, the pressing time is 600 s, the cooling time is 360 s. The plates are pressed with a density of 800 kg / m and a thickness of 0.01 m. Table 2.

Description

The invention relates to the woodworking industry and can be used in the manufacture of wood-based panels on a thermoplastic binder.

The purpose of the invention is to reduce binder consumption.

Coniferous wood chips with a fractional composition of 5/1 humidity 5-7% are mixed in a paddle mixer with a thermoplastic binder. The thermoplastic binder is prepared as follows.

Pre-preparing a mixture of thermoplastic with low density polyethylene with their ratio, wt.% 30-70: 70-30.

Then the resulting mixture is subjected to elastic-deformation grinding in a twin-screw extruder in a known manner to a powder with parameters

Bulk weight 150-220 kg / m3 Particle size Not more than 2.5 mm Thermoplastic binder powder with a bulk weight less than 150 kg / m3 failed to obtain a fibrous structure.

The values of the parameters of the method of manufacturing plates on a thermoplastic binder are presented in Table. 1. Plates are pressed on a laboratory press at 443-453 K with subsequent cooling of the plates.

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Under pressure up to 333 K. The pressing pressure is 2.5 MPa, the pressing time is 600 s, the cooling time is 360 s. The plates are pressed with a density of 800 kg / m and a thickness of 0.01 m.

The test results obtained plates are presented in table. 2

Thus, the invention allows to reduce the consumption of thermoplastic binder at non-deterioration of the physicomechanical parameters of the plates at the optimum values of the parameters of the method.

Claims (1)

Invention Formula A method of making wood boards on a thermoplastic binder, including five The preparation of wood particles and the binder, their mixing and the formation of briquettes, followed by hot pressing of the plates, characterized in that, in order to reduce the consumption of the binder, the preparation of the binder is carried out by mixing thermoplastic with low density polyethylene at their ratio, wt. % 30-70: 70-30, and elastic-deformation grinding of the mixture obtained to the powder with parameters Bulk weight 150-220 kg / m3; Particle size Not more than 2.5 mm, and after hot pressing, the plates are cooled under pressure. Table 1. Table 2.