CS239836B1 - Method of manufacture of plywood from veneer waste - Google Patents

Description

The invention solves a process for the production of wedge plywood from veneer wastes which attack in the manufacture of plywood.

Several methods of treatment of veneer wastes are known in the art. nálupov. The best known of these is the method of implanting. narrow veneer strips from a width of 80 mm to whole sheets with the use of splicing machines, which are used to press the plywood, respectively. sheathing of furniture parts.

This method has so far been poorly performing and has a lot of labor.

Another very common method is chipping and the use of waste in the manufacture of particle board. The most common way to utilize veneer waste is to burn tiny and narrow strips in cofinnes, thereby obtaining thermal energy.

The method described is quick and comfortable, but not always. economic. Abroad, e.g. in the USSR, veneer waste is cut into strips of the same width, e.g. 30 mm, which are then continuously pressed into a continuous strip, jacketed on both sides and used to produce so-called. rebrosklejok.

This method achieves high utilization of wood raw material, but the disadvantage is that production is bound to the supply of complex machinery. In the USA, Japan, λ

The FRG and Finland are sewn together with rigid threads on composite sewing machines for larger formats, which are used as inner layers in technical plywood.

However, the method described is suitable only for thin veneers and especially for poppy trees. At depths greater than 3 mm, e.g. in the beech wood, i.e. the stitches break in the sewing machines.

The above-mentioned shortcomings of the existing methods of treatment of veneer wastes are largely eliminated by the method of production of wedge plywood, which is based on the fact that the veneer strips of larger and smaller widths are stacked side by side and on top of each other. and the second shaped, the wider veneer strips are deposited than the surface layer, then the narrower strips are alternately wider than the center layer on which the wider strips than the surface layer are repositioned, then the veneer strips applied with a waterproof adhesive are compressed at a temperature of Ϊ50 to 200 ^C and a pressure of 2.5 to 4.0 MPa.

The main advantage of the described method of wedge pregleick production is the possibility to use wider and narrower veneer strips for shaped moldings without the need for them. This will greatly increase the capacity of the pressing device without compromising the quality of the finished products.

The method according to the invention will allow an increase in the yield in the production of veneers and plywood, since it will be possible to use veneer strips from a width of 50 mm, while up to now it has been possible to use even veneers from 100 mm wide with current splicing machines. This saves considerable amounts of valuable wood raw material,

In the attached drawing, FIG. 1 shows a method of embedding a double-faced wedge ply; FIG. 2 is the respective final product; FIG. 3 shows the deposition of a one-sided wedge plywood, and FIG. 4 is the respective final product.

EXAMPLE

Dried beech veneers of 1.8 mm thickness in the form of narrower strips 2 50 mm wide, 1300 mm long and wider 1 strips 1 400 mm wide 1300 mm long are coated with a waterproof phenolic glue of the Fenokol type and placed side by side in a press. and on top of one another without stacking, according to FIG. 1, such that the wider veneer strips 1 form surface layers of wedge plywood and the narrower veneer strips 2 in combination with the wider veneer strips 1 serve as inner zones of the product. Pressing is carried out at a temperature of 160 ° C and a pressure of 3.5 MPa. The resulting product is in the form of a double-faced wedge plywood with a longitudinal course of the veneer, fig. 2. Example 2

Dried spruce veneers of 2.5 mm in length, 1200 mm in the form of wider strips 1 of 400 mm width and birch veneer in thickness of 2.0 mm of the same length of 1200 mm, in the form of narrower strips 2 of 100 mtti width are applied with Umaform type waterproof adhesive. self and without stacking in the molding press according to FIG. 3 such that the wider veneer strips 1 form circumferential zones and the narrower veneer strips 2 in combination with the wider veneer strips 1 form the central zone of the wedge plywood. The pressing is carried out at a temperature of 180 ° C and a pressure of 3.0 MPa. The resulting product has the shape of a one-sided, wedge, Figure 4, of a laminate having a longitudinal course of the veneer layers.

The double-sided wedge ply according to the invention can be used in mining, for hitching the ceilings of mining corridors as well as for large-area lining elements of the 1200 x 400 x X 60 mm format. They have a high load-bearing capacity and enable to increase the speed in the construction of mining mines. One-sided wedge-shaped products can be used in the textile industry for the production of weaving boats or as pads in transport and engineering.

Claims (4)

SUBJECT A method of producing wedge plywood from veneer waste, in which the plywood sheets of larger and smaller widths are first dried and applied with a waterproof adhesive, characterized in that the plywood sheets of larger and smaller widths are stacked side by side and stacked so that of which one is straight and the other is shaped, YNÁLEZU deposit wider veneer strips than the surface layer, then alternate with the wider strips the narrower strips than the center layer, on which the wider veneer strips than the surface layer are repositioned, then the veneer strips applied with a waterproof adhesive are pressed at 150 to 200 ° C. and a pressure of 2.5 to 4.0 MPa.