Urea-formaldehyde resin anti-cracking composite board

Abstract

The utility model discloses a kind of urea-formaldehyde resin anti-cracking composite board, including core layer and urea-formaldehyde resin surface layer covered in the core layer at least one surface, the board has four peripheral edges, between the core layer and the urea-formaldehyde resin surface layer, three-dimensional reinforcing fiber net and elastic stress buffer layer are sequentially provided from inside to outside;Through the synergistic effect of built-in three-dimensional reinforcing fiber net and elastic stress buffer layer, internal stress generated due to temperature and humidity change can be efficiently dispersed and absorbed, the crack generation is fundamentally inhibited;Through wave-shaped interface structure, interlaminar bond and anti-peeling performance are greatly enhanced, to prevent interface delamination;Through mechanical anchoring type edge strip, the core pain point that edge is easy to crack and easy to fall off is completely solved, the dimensional stability and durability of board are comprehensively improved from mechanical structure level, and without complex modification, production process is good, effectively solve the problem that urea-formaldehyde resin board inherent brittleness is easy to crack, simultaneously control production cost.

Description

Technical Field

[0001] This utility model relates to the technical field of urea-formaldehyde resin composite boards, and in particular to a urea-formaldehyde resin crack-resistant composite board. Background Technology

[0002] Urea-formaldehyde resin has become one of the most widely used adhesives in the production of engineered wood products due to its advantages such as low raw material cost, relatively simple synthesis process, fast curing speed, high bonding strength, and colorless transparency. However, urea-formaldehyde resin has inherent disadvantages such as high brittleness, poor aging resistance, and high internal stress after curing. As a result, composite boards made from it are prone to cracking or even breaking during use, especially when subjected to temperature changes, humidity fluctuations, or external impacts. This seriously affects the durability and service life of the products. This problem is particularly prominent in the dry and cold northern regions or the hot and humid southern regions, and has become a long-standing technical problem that has plagued the industry. Existing technologies have tried to improve this by adding elastomers for toughening, internal reinforcing materials, or simply increasing the thickness. However, these methods have problems such as limited toughening effect, poor compatibility, complex processes, increased costs, or decreased appearance quality. Other studies, such as resin modification or the addition of formaldehyde scavengers, have focused on water resistance or environmental indicators, but have not effectively solved the fundamental structural defect of crack resistance. Therefore, a crack-resistant composite board made of urea-formaldehyde resin is proposed to address the above problems. Utility Model Content

[0003] The technical problem to be solved by this utility model overcomes the existing defects and can effectively solve the problems in the background art.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0005] A urea-formaldehyde resin crack-resistant composite board includes a core layer and a urea-formaldehyde resin surface layer covering at least one surface of the core layer. The board has four edges. Between the core layer and the urea-formaldehyde resin surface layer, a three-dimensional reinforcing fiber mesh and an elastic stress buffer layer are sequentially arranged from the inside to the outside. The interface between the elastic stress buffer layer and the urea-formaldehyde resin surface layer is a wavy or sawtooth interface.

[0006] As a further improvement of this utility model, the three-dimensional reinforced fiber mesh is woven from glass fiber, basalt fiber or polyester fiber, and its fibers are distributed in the X, Y and Z directions.

[0007] As a further improvement of this utility model, the elastic stress buffer layer is an EVA, PE or TPU material layer with a porous mesh or non-woven fabric structure.

[0008] As a further improvement of this utility model, the four edges of the plate are provided with edge banding strips, and the inner side of the edge banding strips is provided with a mechanical anchoring structure extending into the core layer.

[0009] As a further improvement of this utility model, the mechanical anchoring structure is a continuous distribution of barbs, claws, or T-shaped protrusions.

[0010] As a further improvement of this utility model, the two surfaces of the core layer are symmetrically provided with the three-dimensional reinforcing fiber mesh, the elastic stress buffer layer and the urea-formaldehyde resin surface layer.

[0011] As a further improvement of this utility model, the wave depth or tooth depth of the wavy or sawtooth interface is 0.1-0.5mm.

[0012] As a further improvement of this utility model, the wavy or sawtooth interface formed by the interface between the elastic stress buffer layer and the urea-formaldehyde resin surface layer is a continuous micro-wavy or sawtooth structure formed in advance by calendering or molding process.

[0013] Compared with the prior art, the present invention has the following beneficial effects:

[0014] Through the synergistic effect of the built-in three-dimensional reinforced fiber mesh and elastic stress buffer layer, it can efficiently disperse and absorb the internal stress caused by temperature and humidity changes, fundamentally inhibiting the initiation of cracks; the wavy interface structure greatly enhances the interlayer bonding force and anti-peel performance, preventing interface delamination; the mechanically anchored edge banding strip completely solves the core pain points of easy cracking and easy detachment at the edges, comprehensively improving the dimensional stability and durability of the board from the mechanical structure level, without the need for complex modification, with good processability, effectively solving the problem of inherent brittleness and easy cracking of urea-formaldehyde resin boards, while controlling production costs. Attached Figure Description

[0015] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0016] Figure 1 This is a schematic diagram of the overall structure of a urea-formaldehyde resin crack-resistant composite board according to the present invention.

[0017] Figure 2 This is a cross-sectional structural diagram of a urea-formaldehyde resin anti-cracking composite board according to the present invention.

[0018] Figure 3 This is a schematic diagram of the overall structure of the elastic stress buffer layer of the urea-formaldehyde resin anti-cracking composite board according to this utility model.

[0019] In the diagram: 1. Core layer; 2. Three-dimensional reinforcing fiber mesh; 3. Elastic stress buffer layer; 4. Wavy or sawtooth interface; 5. Urea-formaldehyde resin surface layer; 6. Edge sealing strip; 61. Mechanical anchoring structure. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the present invention. In order to better illustrate the specific embodiments of the present invention, some parts in the drawings may be omitted, enlarged or reduced, and do not represent the actual product size. All parts involving precision gear structures and rotating structures are provided with protective structures and sealing mechanisms, which will not be repeated in this application. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Example 1

[0022] like Figure 1-3 As shown, a urea-formaldehyde resin anti-cracking composite board includes a core layer 1 and a urea-formaldehyde resin surface layer 5 covering at least one surface of the core layer 1. The board has four edges. Between the core layer 1 and the urea-formaldehyde resin surface layer 5, a three-dimensional reinforcing fiber mesh 2 and an elastic stress buffer layer 3 are sequentially arranged from the inside to the outside. The interface between the elastic stress buffer layer 3 and the urea-formaldehyde resin surface layer 5 is a wavy or sawtooth interface 4.

[0023] Furthermore, such as Figure 2 As shown, the three-dimensional reinforcing fiber mesh 2 is woven from glass fiber, basalt fiber, or polyester fiber, with its fibers distributed in the X, Y, and Z directions. By limiting the three-dimensional reinforcing fiber mesh 2 to be woven from glass fiber, basalt fiber, or polyester fiber, and ensuring that its fibers are distributed in the X, Y, and Z directions, it can be ensured that the reinforcing mesh can provide a comprehensive three-dimensional reinforcement effect, effectively transmit and disperse stress from different directions, significantly inhibit the propagation of cracks between different layers, and thus comprehensively improve the dimensional stability and crack resistance of the plate.

[0024] Furthermore, such as Figure 2-3 As shown, the elastic stress buffer layer 3 is a porous mesh or non-woven fabric structure of EVA, PE or TPU material layer. By limiting the elastic stress buffer layer 3 to a porous mesh or non-woven fabric structure of EVA, PE or TPU material layer, the porous flexible structure can be used to efficiently absorb and buffer the internal stress caused by temperature and humidity changes. Its excellent elastic deformation ability can prevent stress from being transmitted to the brittle surface layer, thereby fundamentally avoiding the generation of microcracks.

[0025] Furthermore, such as Figure 1-2As shown, the board has edge banding strips 6 around its perimeter. The inner side of the edge banding strips 6 has a mechanical anchoring structure 61 extending into the core layer 1. By setting edge banding strips 6 with mechanical anchoring structures 61 around the perimeter of the board, the edge banding strips 6 can be tightly bonded to the core layer 1 through physical anchoring, thereby providing peel strength far exceeding that of traditional adhesives, fundamentally solving the problem of cracking and falling off caused by stress concentration and moisture intrusion at the edges of the board.

[0026] Furthermore, such as Figure 2 As shown, the mechanical anchoring structure 61 consists of continuously distributed barbs, claws, or T-shaped protrusions. By further defining the mechanical anchoring structure 61 as continuously distributed barbs, claws, or T-shaped protrusions, these structures can be firmly embedded into the core layer 1 during the edge sealing process, forming an extremely reliable mechanical interlock. This greatly enhances the durability and reliability of the edge protection, making the edge sealing strip 6 difficult to peel off.

[0027] Furthermore, such as Figure 1-3 As shown, the two surfaces of the core layer 1 are symmetrically provided with the three-dimensional reinforcing fiber mesh 2, the elastic stress buffer layer 3, and the urea-formaldehyde resin surface layer 5. By symmetrically setting the reinforcing mesh, buffer layer, and surface layer on the two surfaces of the core layer 1, the mechanical balance characteristics of the symmetrical structure can be utilized to ensure that the stress changes on both sides of the board are synchronized under environmental changes, thereby effectively preventing warping deformation caused by unidirectional stress and ensuring the flatness of the board while resisting cracking.

[0028] Furthermore, such as Figure 2 As shown, the wave depth or tooth depth of the wavy or sawtooth interface 4 is 0.1-0.5mm. By limiting the wave depth or tooth depth of the wavy or sawtooth interface 4 to the range of 0.1-0.5mm, a balance can be achieved between the optimal mechanical interlocking effect and the feasibility of the production process. This ensures the interface bonding strength, avoids stress concentration, and ensures that the resin can be fully filled without producing defects.

[0029] Furthermore, such as Figure 2 As shown, the wavy or sawtooth interface 4 formed at the interface between the elastic stress buffer layer 3 and the urea-formaldehyde resin surface layer 5 is a continuous micro-wavy or sawtooth structure pre-processed by calendering or molding. By limiting the wavy or sawtooth interface 4 to be pre-processed by calendering or molding, it can be ensured that the shape, depth and distribution of the interface structure remain highly consistent and precisely controllable. This allows for the stable achievement of optimal mechanical interlocking force and stress dispersion effect in mass production, avoiding the problem of uneven interface bonding caused by the uncertainty of resin flow, and fundamentally ensuring the reliability and consistency of the product's crack resistance performance.

[0030] The processing flow of composite panels is as follows: First, prepare the core layer panel (i.e., core layer 1) as the substrate and clean its upper and lower surfaces. Then, lay three-dimensional reinforcing fiber mesh 2 on the upper and lower surfaces of core layer 1 respectively. Next, cover the laid fiber mesh with an elastic stress buffer layer 3 (the surface of this buffer layer that contacts the urea-formaldehyde resin surface layer 5 has been pre-processed by calendering or molding to form a continuous micro-wave-shaped or sawtooth structure, i.e., a wave-shaped or sawtooth interface 4, which is a key preparatory step for forming a mechanical interlocking interface). After covering, place decorative paper impregnated with urea-formaldehyde resin (i.e., urea-formaldehyde resin surface layer 5) on the formed buffer layer. The formed blank is fed into a hot press and hot-pressed under specific temperature, pressure and time parameters. During this process, the molten urea-formaldehyde resin will fully penetrate and fill the wavy or sawtooth grooves on the surface of the buffer layer under pressure. After hot pressing, the urea-formaldehyde resin is cured after a cooling and shaping process. The cured resin is tightly bonded to the wavy / sawtooth surface of the buffer layer to form a strong "resin-groove" mechanical interlocking structure, namely the wavy or sawtooth interface 4. Finally, the edge banding strip 6 with barbs, hooks and other mechanical anchoring structures 61 is pressed into the four edges of the board by mechanical means to complete the processing of the entire board.

[0031] The above are preferred embodiments of the present invention. The basic principles, main features, and advantages of the present invention have been shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope thereof. All such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A urea-formaldehyde resin crack-resistant composite board, comprising a core layer (1) and a urea-formaldehyde resin surface layer (5) covering at least one surface of the core layer (1), the board having four edges, characterized in that: Between the core layer (1) and the urea-formaldehyde resin surface layer (5), a three-dimensional reinforcing fiber mesh (2) and an elastic stress buffer layer (3) are arranged sequentially from the inside to the outside; the interface between the elastic stress buffer layer (3) and the urea-formaldehyde resin surface layer (5) is a wavy or sawtooth interface (4).

2. The urea-formaldehyde resin crack-resistant composite board according to claim 1, characterized in that: The three-dimensional reinforced fiber mesh (2) is woven from glass fiber, basalt fiber or polyester fiber, and its fibers are distributed in the X, Y and Z directions.

3. The urea-formaldehyde resin crack-resistant composite board according to claim 1, characterized in that: The elastic stress buffer layer (3) is an EVA, PE or TPU material layer with a porous mesh or non-woven fabric structure.

4. The urea-formaldehyde resin crack-resistant composite board according to claim 1, characterized in that: The board has an edge banding strip (6) around its perimeter, and the inner side of the edge banding strip (6) has a mechanical anchoring structure (61) extending into the core layer (1).

5. The urea-formaldehyde resin crack-resistant composite board according to claim 4, characterized in that: The mechanical anchoring structure (61) is a continuously distributed barb, claw, or T-shaped protrusion.

6. The urea-formaldehyde resin crack-resistant composite board according to claim 1, characterized in that: The core layer (1) has the three-dimensional reinforcing fiber mesh (2), the elastic stress buffer layer (3) and the urea-formaldehyde resin surface layer (5) symmetrically arranged on both surfaces.

7. The urea-formaldehyde resin crack-resistant composite board according to claim 1, characterized in that: The wave depth or tooth depth of the wavy or sawtooth interface (4) is 0.1-0.5 mm.

8. The urea-formaldehyde resin crack-resistant composite board according to claim 1, characterized in that: The wavy or sawtooth interface (4) formed by the interface between the elastic stress buffer layer (3) and the urea-formaldehyde resin surface layer (5) is a continuous micro-wavy or sawtooth structure formed in advance by calendering or molding process.

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