RU2654793C1 - Method of plywood manufacturing - Google Patents

Abstract

FIELD: wood-working industry.

SUBSTANCE: invention relates to woodworking industry, in particular to manufacture of plywood. On front layer of veneer, binder is applied from both sides by means of gum applicators and laid on packing material containing polyethylene terephthalate film or polyethylene terephthalate film. Then, the binder is applied to inner longitudinal and transverse veneer layers. Collect an assembly that closes front layer with applied binder, and on top of the front layer stacked packing material. Holding of the collected assembly in packing material is carried out in a cold pressure machine at specific pressure of 9–10 kg/cm² within 10–20 minutes. Then premolded assembly is transported in the packing material to hydraulic hot pressure machine where, for 17 to 68 minutes, the assembly is glued at specific pressure of 20–21 kg/cm² and temperature 118–135 °C. Perform the storage of glued bakelized plywood sheets in the packing material, after which the packing material is separated from finished plywood sheets, plywood sheets are cut and edges is processed.

EFFECT: simplifies the process of plywood manufacturing.

1 cl, 4 tbl, 1 dwg

Description

The invention relates to the woodworking industry, and in particular to a method for producing, in particular, a method of manufacturing plywood.

State of the art

Closest to the claimed method is a method for producing plywood by gluing veneer sheets assembled in a bag in presses with the corresponding plate format. In this case, the operation of assembling packages consists in selecting and laying veneers in accordance with a given design and grade of plywood ("Handbook of plywood production" edited by N.V. Kachalin: Forestry, 1984, p. 171).

In the production of bakelized plywood, the veneer face layers are treated with phenol-formaldehyde resins or bakelite varnish.

To prevent the packets from sticking together, as well as sticking to the surfaces of the hot press plates, it is necessary to either dry the treated veneer first or use cushioning material.

The claimed method solves several problems at once.

1. There is no need to dry the veneered face layers treated with phenol-formaldehyde resin or bakelite varnish.

2. Protection against sticking of veneered face layers of veneer treated with phenol-formaldehyde resin or bakelite varnish to the surfaces of hot press plates.

3. There is no possibility of damage to the surface of the hot press plates, unlike traditional duralumin gaskets.

To solve these problems, in the claimed method, polyethylene terephthalate film (hereinafter referred to as PET) with a thickness of 250 to 350 μm, a length of 2610 mm, a width of 1350 mm is used as a cushioning material for the assembled bags.

The technical result of the claimed method is the absence of a drying stage of veneer face layers treated with phenol-formaldehyde resins, ease of use, increase in the protective functions of the surface of hot press plates, by eliminating the possibility of damage to the surface of press plates.

The technical result in the claimed method is achieved through the use of cushioning material, namely a lining material containing a polyethylene terephthalate film, or a polyethylene terephthalate film as a lining material. Moreover, such a lining material can be used repeatedly.

The essence of the claimed method

The starting materials for the production of plywood in the claimed method are:

- birch veneer with tolerances on the limits of wood defects and humidity not more than 6 ± 2% according to GOST 99-96 "Rotary cut veneer".

For the front layers of plywood, birch veneer of varieties BB (II) and CP (III) are used in accordance with GOST 11539-2014 “Baked plywood. Technical conditions "; TU 5515-001-89412043-16 "Baked plywood. Technical conditions. "

- Bakelite varnish brand LVS-1 GOST 901-78 "Bakelite varnishes";

- phenol-formaldehyde resin brand SFZh-3093 TU 6-05751768-70-94.

The technological arrangement of equipment for the assembly process of plywood packages is shown in figure No. 1.

The following equipment is used to produce plywood:

three gluing machines (pos. 1, 2, 3),

a container with LBS-1 varnish or resin grade SFZh-3093 (item 4),

lifting tables (pos. 5, 6),

three lifting tables with roller conveyor (pos. 7, 8, 9),

disk table (pos. 10),

underground place (pos. 11),

roller conveyors (pos. 12, 13, 14).

As a cushioning material for the production of plywood, a polyethylene terephthalate film (hereinafter referred to as PET) is used with a thickness of 250 to 350 μm, a length of 2610 mm, a width of 1350 mm. PET has the inherent properties that are needed in the production of Bakelized Plywood, i.e. withstands high temperature, high pressure, is amorphous (there is no possibility of adhesion and interaction with the surface of the face layer coated with synthetic resins).

For convenience and extending the life of PET, FSF brand plywood of the format 2610 × 1350 × 4 mm, grades II / IV or III / IV, Sh2 is used as the basis for laying. A PET film is attached to the plywood from the side of grade II or III around the perimeter using a stapler. Prepared cushioning material is lubricated with distilled fatty acids (DLC) or technical oil of any brand.

The bags are assembled directly on pre-prepared gaskets on the side of the PET-coated film or simply on a PET film, as cushioning materials installed in the storage space (item 11).

The bottoms container with a binder (synthetic resins - LBS-1 bakelite varnish or SFZh-3093 phenol-formaldehyde resin) is installed in another place (pos. 4) and connected to the feed system to the applicator (pos. 2). Depending on the brand of bakelized plywood produced, two or three gluing machines can take part in the process (pos. 1, 2, 3). If necessary, the varnish is supplied to three applicators.

The applicator (pos. 1) is intended for applying synthetic resins to the veneer of the inner transverse layers of plywood.

The applicator (pos. 2) is intended for applying synthetic resins to the veneer of the inner longitudinal layers of plywood. For the brand FBS ₁ -A-T, FBV ₁ -T - for applying synthetic resins to the veneer of the front longitudinal layers.

The gluing machine (item 3) is intended for applying synthetic resins to the veneer of the front longitudinal layers of plywood in the production of Bakelized plywood of the FBS, FBS ₁ , FBV grades.

Synthetic resins are applied by passing veneer sheets between the rotating drums of the machine with a preliminary set of resin on the front edge of the sheet.

диаметра.The resin must be supplied to the applicator periodically in small portions so that its level ensures that the lower drum is immersed by at least

diameter.

Glue applicators should ensure uniform application of resin on both surfaces of each sheet without gaps and smudges. To comply with this rule, when applying synthetic resins to a longitudinal veneer on gluing machines No. 2 and No. 3, a circulation system is provided.

Technological norms for the consumption of a binder (varnish, resin) per square meter of the veneer surface to be coated are given in table. 1. In particular, the binder consumption on the outer layers is 120 g / m ² , the binder consumption on the inner layers, depending on the brand of plywood, is 115-150 g / m ² .

Package assembly

The veneer coming to the assembly must meet the requirements of this instruction on humidity and grade (for the front layer). The front layer is not allowed with the presence of staples from the stapler, masking tape, double inserts, in connection with the passage of the front layer through the applicator.

The bags are assembled directly on previously prepared gaskets on the side covered with PET film, or simply on a PET film.

Using a gluing machine No. 2 (figure No. 1), bakelite varnish or phenol-formaldehyde resin is applied, depending on the brand of plywood produced, on the front layer, which is a veneer of grade BB (II) or CP (III) according to GOST 99-96, stacked on the gasket. Then, using a gluing machine No. 1 (figure No. 1), bakelite varnish or phenol-formaldehyde resin is applied to the inner transverse layer. It is allowed to use incomplete veneers on the inner layers with the condition that when assembling the mismatch of the edge joints in parallel layers. In the production of bakelized plywood of the FBS, FBS ₁ , FBV grades, the gluing machine No. 2 (figure No. 1) is used for applying synthetic resins to the inner longitudinal layers; gluing machine No. 3 (figure No. 1) is used for applying synthetic resins to the front layers.

The finished bag is closed with a coated face layer, then a gasket coated with a PET film or just a PET film is placed.

The following rules must be observed during package assembly:

1. The outer layers of plywood should be made of whole or no more than two pieces of veneer along the width or length of the plywood sheet. Veneer joints should not coincide in longitudinal layers along the thickness of plywood.

2. On the surface of plywood are not allowed areas not covered with resin.

3. In the inner layers of plywood, wood defects and processing defects are allowed that do not affect its quality and size. When compiling sheets of non-full-length veneers, overlays of veneers of no more than 10 mm and gaps between the edges of veneers are not more than 5 mm are allowed.

4. The assembly of packages is made with the alignment of two mutually perpendicular edges in a "right angle".

5. To prevent the occurrence of internal stresses that lead to warping of plywood, the overlap - the inner longitudinal layer, must be turned upside down using a tilter.

6. With an odd number of veneer layers in the package, all veneer layers should have a mutually perpendicular direction of the wood fibers.

7. An assembly scheme with an even number of layers is allowed. With an even number of layers in the package, two layers of veneer with a parallel direction of the wood fibers are allowed.

8. If the repair insert falls off the surface of the face layer, it is necessary to insert this insert into place and coat it with varnish or resin, depending on the order.

Cold pressing packages before gluing

The prepress is an endurance of the assembled veneer packages in a cushioning material with a PET film under pressure in a cold press before gluing them.

The purpose of the prepress is to obtain a formed package in which the veneer sheets are glued together, as well as with a PET film, as a result of which the packages acquire the necessary stiffness and transportability. This contributes to the defect-free loading of packages into the hot press, eliminates the shift of veneer sheets among themselves. Due to this, reliable fixing of the cushioning material to the jacket layers in each bag is achieved. Prepressing can be carried out both in automatic and in manual mode.

A hydraulic hydraulic press, using a transport trolley, moves a stack of veneer packets into a cold press. This foot is centered in a cold press, then a compression program is started.

The mode of pressing the packages in a cold press is shown in Table 2. The collected veneer packages in a cushioning material with a PET film are aged in a cold press at a specific pressure of the cold press of 9-10 kg / cm ² for 10-20 minutes, which depends on the brand of plywood.

Bonding veneer packages

Bonding of plywood is carried out in multi-story hydraulic hot presses.

Prepressed packages are transported in gaskets along a roller conveyor to a lifting table. The table is lifted and automatically, with the help of photocells, maintained at a given height so that the top package is at the level of the loading rollers.

- for the Cremona hot press - the temperature, hydraulic pressure and time of pressing the bags by thickness are set;

- for the hot press “Kitagawa” - the pressing model is selected.

Prepressed bags with cushioning material (containing PET film) are loaded from the upper and lower sides through a conveyor belt into the loading shelf. The whatnot, driven by hydraulic cylinders, moves vertically between the frames.

After loading and centering the packages, the press plates are closed and the pressure is increased. After reaching the standard pressure, the time for holding the packets at the operating temperature begins.

The duration of pressing plywood is shown in table 3.

Depending on the brand of products and the thickness of the package bonding veneer packages is carried out at a specific pressure of 20-21 kg / cm ² ; a temperature of 118-135 ° C, for 17-68 minutes (where the gasket warm-up time is 3 minutes).

After the pressing process is completed, the bakelized plywood in the cushioning material is unloaded into the unloading whatnot. Then, under the control of the valve, finished products in the cushioning material are unloaded on the lifting table.

Parsing packs

A pack of glued sheets of bakelized plywood in the cushioning material is sent with a loader to the place for standing for 30-40 minutes.

After maturation, a bundle of finished products is put on a stand under and disassembled as follows: finished products in one foot, cushioning material in another foot. When parsing, the plywood is turned 180 ° to remove the lower cushioning material. The cushioning material, before laying in the foot, is treated with waste oil or grease.

Trimming and processing

The glued sheets of bakelized plywood are cut from four sides on a format-cutting line, while the correct location of the "right angle" must be taken into account.

The dimensions of the sheets of bakelized plywood should correspond to the values indicated in table 4.

Plywood sheets on which defects were found as a result of sheet sorting are subject to refinement.

Edges of plywood sheets are varnished after sorting. The sizes of the sheets vary in length and width from 1220 mm ÷ 2500 mm (1.22 ÷ 2.5 m).

The inventive method has passed multiple tests in real operating conditions. As a result of comparison with the traditional method of manufacturing bakelized plywood using duralumin gaskets or by drying the treated veneer layers, this method, using a cushioning material with a polyethylene terephthalate film (hereinafter referred to as PET) or using a polyethylene terephthalate film as a cushioning material, is easier to use eliminates the technological process of drying the processed facial veneer, the PET film does not adhere to the finished product, nor to the surface oryachego hydraulic press, ie is amorphous.

Claims (1)

A method of producing plywood, which includes successive stages of assembling packages consisting of veneer layers, cold pressing the assembled packages before gluing, gluing the pressed packages in a hot press, standing, sorting out packs of finished sheets of bakelized plywood, cutting and processing sheets of bakelized plywood, where at the stage of assembling the packages a binder is applied to the front layer from two sides using gluing machines and laid on a cushioning material containing a polyethylene terephthalate film or and a polyethylene terephthalate film in the form of a cushioning material, then a binder is applied to the inner longitudinal and transverse layers of the veneer, collecting a package that is closed by the front layer with the applied binder, and the cushioning material is laid on top of the front layer, then the collected package is sent to the cold pressing stage before by gluing, wherein a shutter assembled package gasket material is carried out in a cold press at a specific pressure of the cold press is 9-10 kg / cm ² for 10-20 min, then under ressovanny packet transported in the gasket material on the bonding stage in a hydraulic hot press, where for 17-68 min bonding is performed at a pressure package 20-21 kg / cm ² and a temperature of 118-135 ° C, then glued plywood sheets bakelized gasket material sent for maturation, after which, at the stage of parsing the packs of finished plywood sheets, the cushioning material is separated from the finished plywood sheets, which are sent to the final cutting and processing stage, where the plywood sheets are cut and rabotku edges.

Images