LV14425B - Three-layered composit material made as sandwich board and method for its manufacturing - Google Patents

Abstract

The invention pertains to a light-weight sandwich board manufacturing process. The product conditionally can be divided into three parts: the core layer which is covered with a covering material from both sides by gluing. The core layer consists of a multi-layered material made, in particular, of veneers and glued to each other so as to form a corrugate panel. The small dimension corrugated panels are manufactured and stitched together, in particular by gluing, in order to form panels of large dimension in length and width.

Description

Description of the Invention

The invention relates to the field of materials science, in particular to the wood materials and technology sub-sector. The field of application of multiple wood composite materials is furniture, structural and enclosing elements, etc. This structure of wood composite materials increases the stiffness and load-bearing capacity of the board materials, and at the same time produces an article with increased specific strength.

Analysis of prior art

U.S. Patent Nos. 4,816,103 and 4,943,339 describe a method and apparatus for manufacturing three-dimensional slabs. The press consists of several sections. This prevents veneer printing and ensures gradual retraction. The authors of the above-mentioned patent applications propose to place a fiberglass cloth over the veneers to improve the sliding of the veneer package along the press plates. Fiberglass fabric can be replaced with tefion or graphite powder. US patent US 7429171 provides a machine for bending board materials. The production of three-dimensional slabs using chopped wood is easier. Such plates can be produced by extrusion or extrusion in various molds. An apparatus for manufacturing corrugated wood particle board is described in U.S. Patent Nos. 4,616,991 and 5,000,673. Press plates are designed to form two types of surfaces, a flat plane that can be mechanically converted to a corrugated plane. US patent application US 4904517 proposes a particle board with one plane flat and the other wavy. The board manufacturing process can be divided into three parts: coating of wood particles treated with binder; applying an additional layer of wood particles and binder to the formed coating at a relative interval, forming a wavy top plane by pressing the coating. US Patent No. 7077988 describes roller coating, but U.S. Pat.

Application US 5443891 proposes the creation of grooves embedded in press plates using them to form corrugated plates. In order not to reduce the pressure on the wood particle coating, it is suggested to form the wood particle coating on a metal mesh. This provides the necessary pressure. The inventor states that the bending moment of low profile wood particle boards at the same weight per unit area is 60% higher than that of a flat board. As a workaround, U.S. Patent No. 7426806 proposes to change the radius of the curvature to provide additional pressure and create a thinner cross-section. Such corrugated boards can additionally be bonded to the board materials to produce material that is similar in appearance to traditional board materials. A similar composite material is described in U.S. Patents US 6,511,567, US 6,773,791, and US 7255765. The composite material defined therein is relatively composed of a corrugated core and paneling material. U.S. Patent No. 7,077,988 and U.S. Patent Nos. 5,443,891, 5,000,673,383, 4,945,417, 4,934,339, 4,816,103 describe the production of corrugated board and equipment for making it using wood raw materials (e.g., wood fibers, chips, veneers and / or other materials). One of the problems in making waveguides is the various bend radii at the bends of the wave, and it should be noted that the wavelength of the wavy structure is greater than the length of the tangent drawn over the waves. Therefore, to produce a waveguide board of a certain length, a larger-sized flat surface material is needed, which then bends it into traditional molds and flattens them according to the relief of the mold. The last three patent applications describe the production of curved plywood products using wood veneer sheets.

Purpose and substance of the invention

The purpose of the present invention is to provide a three-layer composite plywood composite material and a technological description thereof for the purpose of increasing the useful performance of the wood while reducing the structural weight of the wood board while maintaining high mechanical properties.

The present invention relates to lightweight slabs and a method for their production. The product consists of three parts; middle layers, which are glued on both sides with surface material. The middle layer consists of a multilayer material, preferably a veneer, glued together to form a corrugated board. To form a large plate in length and width, small corrugated plates are made, which are then glued together in a continuous plate. The three-dimensional plywood is preferably made of birch veneers, the fibers of adjacent layers being perpendicular to each other. In this way, the composite material with twice the bulk density can be obtained than a full-ply plywood of the same thickness.

The invention will be better understood by reference to the accompanying drawings:

Fig. 1 shows a corrugated middle layer structure of composite plywood panels;

- Fig. 2 shows the structure of the composite plywood panels and the middle layer;

Fig. 3 shows a wavy middle layer connection;

- Fig. 4 shows the layout of the panel before insertion;

- Fig. 5 shows the press installation;

- Fig. 6 shows the finished panel.

The middle layer 3 shown in Fig. 1 consists of several corrugated plates of smaller size interconnected together. The panels 3 are secured to one another, preferring a bonded joint, but metal attachments, nails, screws or other mechanical means may be used to secure the joint.

Fig. 2 shows a layered material made with the middle layer of a corrugated plate. This material is made by preferring the manufacturing method described in the invention. Corrugated plates can be made with different number of waves, wave radii and plate thickness B. The height A of the corrugated plate can be varied depending on the required thickness of the final composite plate and the thickness of the cladding plates. The height C of the first wave is A-B + n, where n is the tolerance that depends on the thickness B of the wave plate.

Figure 3 shows a corrugated board connection in which part a) shows a connection of corrugated boards 3 with surfaces D and G before being pressed between the press plates 6 and 7. Corrugated boards 3 are arranged between the cladding boards 1 and 2. Figure 3 b) shows the connection of the corrugated plates 3 in a pressed position between the plates 6 and 7.

Fig. 4 shows the arrangement of panels between the cladding panels 1 and 2 and the corrugated panels 3, showing the corrugated panel connection D and G prior to insertion, with adhesive or other binder being applied to the surfaces G, D and E prior to insertion. In addition to the connection points G, D and E, heat can be supplied or placed in a high frequency current field, which reduces production time. In addition, other connector means may be used at the connection points.

Fig. 5 shows the composition of composite plywood panels 1, 2 and 3 and the positioning of compound D and G in the press between smooth press panels 6 and 7.

Figure 6 shows a ready made composite plywood panel consisting of panels 1, 2 and 3, whereby the width, length and overall thickness of the laminated panel can be adapted to the requirements of the consumer.

The present invention is based on the production of composite plywood panels, which consist of a corrugated middle layer and panel material cladding. The manufacturing process of three-layer composite plywood starts with the production of a wavy middle layer. The middle layer is intended to be made of interconnected smaller sized multiple corrugated boards, forming large panels in both length and width.

The prepared corrugated plates are interconnected, preferring the connection type shown in Fig. 2. The panels may be glued, bolted, nailed together or otherwise mechanically bonded to each other to ensure uniform strength of the center coat over the entire area. The middle layer is intended to be made of laminated materials, with the preference of interlocking wood veneers. Making smaller waveguides and further joining them solves the problem of wavy bending of the plate material - the length of the curvature exceeds the length of the raw material inserted in the press and thus the tensile stresses in the corrugated plate can occur.

-5 zones of varying thickness and strength are formed. The boards can be joined together in unlimited numbers to form large boards (see Fig. 4). When a large corrugated board is obtained, it is further glued with flat board materials using a press (see Fig. 5). In addition, metal nails, clamps, screws or other fasteners may be used to improve the joint strength.

The adhesive can be applied to both flat and corrugated surfaces. For flat elements, the adhesive may be applied, for example, by the pouring method. For a corrugated board, the binder can be applied by passing the board through rollers on which the binder is applied.

To improve adhesion, the collected pack is pressurized. The press plates can be unheated or heated to reduce the pressing time, and the adhesive setting time can be reduced by using a high frequency current field. Large panels can be cut to size.

The use of triple plywood composite panels is intended for lightweight enclosures (eg self-supporting wall panels, office work area separation panels); load-bearing elements (eg floor beams, floor slabs), transport industry (eg floor and wall freight containers).

Sources of information (A - patent applications, B - patents):

1. US 4816103 A, 1989. Process for manufacturing corrugated plywood composites.

2. US 4943339 A, 1990. Apparatus for manufacturing corrugated plywood composite.

3. US 4616991 A, 1986. Apparatus for the manufacture of a corrugated wafer board panei.

4. US 4904517 A, 1990. Ribbed waferboard product.

5. 5000673 A, 1991. Process and apparatus for preparing a flattopped vave board panei.

6. US 7429171 B, 2003. Device for sbeet material corrugation.

-67. US 5443891 1995, 1995. Lgw amplitude wave board.

8. US 6511567 B, 2003. Composite building components and method of making same.

9. US 7426806 B, 2008. Reverse molded panei, method of manufacture, and door manufactured therefrom.

10. US 6773791 B, 2004. Composite building components and method of making same.

11. US 6541097 B, 2003. Ribbed board.

12. US 7077988 B, 2006. Corrugated fiberboard panels for use in the construction of walls, ceilings and floors.

13. US 7255765 B, 2007. Method of making a composite building material.

Claims (3)

1. A three-layered composite sheet with a corrugated plywood core made from a plurality of interconnected smaller plywood corrugated sheets. A method of manufacturing a triple-layer composite board according to claim 1, comprising the steps of: - making a plurality of smaller sized corrugated plywood panels interconnected to form a larger size panel, preferring the type of connection shown in Figure 2, whereby the panels may be further bonded, screwed or otherwise mechanically bonded to increase the strength of the joints; - bonding corrugated plywood panels with flat panels, whereby, in order to improve adhesion, the composite composite package can be pressed (see Fig. 5), which panels can be heated, or a high frequency current field can be used to promote cure , as well as improving the strength of said flat plate and corrugated middle layer joints -7such nails, screws, clamps or other mechanical fasteners may be used. A method of manufacturing a triple-layer composite slab according to claim 1, comprising the steps of: - production of several smaller sized plywood panels; - forming a triple layer composite material using two flat sheets of outer ply and a plurality of smaller sized plywood panels in the middle layer, with one side of the outer ply being bonded with a binder, a small roll of plywood forming a binder on the bonded surface, middle layer, preferring Fig. 2; the joint illustrated, whereby, for added strength, the bonding points of the plywood boards may be covered with a binder, then said middle layer covered with a second flat bonding sheet, followed by a lower plane facing the plywood with a binder; - in addition to improving adhesion, the composite composite package can be pressed into a press (see Fig. 5), the panels of which can be heated to promote curing of the adhesive, and a high frequency current field can be used for this purpose.