Flexible plain-color triamine film, plain-color ecological board thereof and preparation method of plain-color ecological board

Abstract

The invention discloses a flexible plain-color triamine film and a preparation method thereof, and the preparation method comprises the following steps: 1) coating the back surface of plain-color decorative paper with a back coating liquid, and drying to form a back coating layer, the back coating liquid at least comprising titanium dioxide and an acrylic emulsion; 2) dipping in a urea-formaldehyde resin dipping solution, and drying to form a covering layer surrounding the film material in the step 1); (3) coating the double surfaces with amine-aldehyde resin, and drying to form shielding layers at least covering the front surface and the back surface of the film material in the step (2); and (4) a non-woven fabric substrate is laid on the outer side of the shielding layer on the same side as the back coating, then a concave-convex surface is formed through coining, the coining depth does not exceed the shielding layer, the prepared flexible plain-color triamine film has excellent covering power, triamine facing on the surface of the fast-growing wood plywood is successfully achieved, and the service life of the fast-growing wood plywood is prolonged. The invention further discloses the plain-color ecological board containing the flexible plain-color triamine film and a preparation method of the plain-color ecological board.

Description

Technical Field

[0001] This invention belongs to the field of board manufacturing technology, specifically relating to a flexible solid-color melamine film. This invention also relates to a method for preparing the flexible solid-color melamine film, and a solid-color eco-board including the flexible solid-color melamine film and its preparation method. Background Technology

[0002] With the changing styles of interior design, the Italian minimalist style has become popular in recent years, and decorative panels and furniture with a plain, flat finish are increasingly favored. Decorative panels with a plain, flat finish mainly include painted panels, polymer film panels, and impregnated paper panels.

[0003] Among them, impregnated paper veneer panels using melamine finishing technology offer high cost-effectiveness and excellent surface performance, making them the mainstream choice for furniture and decorative panels. Currently, the substrates used for solid-color flat effects in this type of veneer panel are generally relatively smooth fiberboard or particleboard, but fast-growing plywood with a strong solid wood feel is rarely used, mainly due to the following issues:

[0004] First, fast-growing plywood generally has minor defects such as sand marks and knots on its surface. The melamine finishing process uses solid-color printing paper with a high paper yield, which generally has a weight of 70 to 90 grams per square meter and low opacity. As a result, any slight quality defects on the surface of fast-growing plywood will be further amplified during the melamine finishing process.

[0005] For example, poplar plywood and engineered wood veneer plywood are popular among consumers due to their excellent moisture and water resistance.

[0006] However, in the process of applying impregnated paper veneer with a plain flat effect, poplar plywood may have quality defects such as small white spots or show-through due to the natural small knots in the poplar veneer. While engineered wood veneer plywood does not have the quality defect of small white spots, it is prone to shedding wood fibers and uneven color. When applying conventional plain impregnated paper veneer, it is easy to have problems such as wood grain showing through and uneven color showing through.

[0007] In addition, since the substrate of fast-growing plywood is mainly made by hand, overlap is inevitable when splicing. After melamine finishing, the surface of the board will have a wavy pattern, which is especially obvious when made into a plain flat surface, affecting the appearance.

[0008] To address the issue of melamine veneer easily showing through fast-growing plywood, patent document CN104875246B discloses a melamine multilayer plywood and its preparation method, comprising the following steps: A) using symmetrical eucalyptus veneers as core boards, bonding them with pre-made adhesives, and then applying poplar veneer to the outer surface of the core boards and bonding it with pre-made adhesives to form a substrate, wherein the moisture content of the substrate is less than 13%; B) applying pre-made melamine-impregnated paper to the surface of the substrate, and then pressing it with a hot press at a temperature of 110-130℃ and a pressure of 600-900 tons for 380-450 seconds to form a melamine multilayer plywood.

[0009] The aforementioned prior art discloses that its base paper contains 10-15% by weight of titanium dioxide, which can achieve the effect of avoiding the bottom showing through. However, the prior art does not disclose the manufacturing process of its base paper containing titanium dioxide. At the same time, titanium dioxide, which has no adhesive properties, comes into direct contact with other structural layers or adhesives, which has an adverse effect on the composite strength of the board.

[0010] Second, plywood made from fast-growing wood is prone to surface defects such as burrs, sand marks, and roughness, meaning its surface flatness is relatively poor. Meanwhile, conventional melamine-impregnated paper has relatively high hardness, making it difficult for the two to make full contact and evenly press together, which can easily lead to problems such as bubbling and dried spots.

[0011] Third, plywood made from fast-growing wood generally uses urea-formaldehyde resin glue, which requires a large amount of glue and has a high formaldehyde release. The surface lamination is generally a low-temperature, long-time process, which is inefficient, has poor surface wear and scratch resistance, and the board surface is prone to cracking, affecting the use effect.

[0012] The applicant and inventor have been deeply involved in the research and development of melamine finishes and board preparation for many years. Based on the above research, they believe that there is still room for improvement in the technology of using fast-growing plywood as the base material for melamine finishes. Summary of the Invention

[0013] In response to the problems in related technologies, this invention proposes a flexible solid-color melamine film to overcome the aforementioned technical problems existing in the prior art; at the same time, this invention also discloses a method for preparing the flexible solid-color melamine film and a solid-color ecological board including the flexible solid-color melamine film and its preparation method.

[0014] The technical solution of the present invention is achieved as follows:

[0015] A method for preparing a flexible solid-color triamine film includes the following steps:

[0016] 1) Apply a back coating liquid to the back of plain decorative paper, dry it to form a back coating layer, wherein the back coating liquid contains at least titanium dioxide and acrylic emulsion;

[0017] 2) Impregnate with urea-formaldehyde resin impregnation solution, dry, and form a covering layer surrounding the film material in step 1);

[0018] 3) Coat both sides with amine-formaldehyde resin and dry to form a shielding layer that at least covers the front and back sides of the film material in step 2);

[0019] 4) A non-woven fabric substrate is laid on the outside of the shielding layer on the same side as the back coating, and then embossed to form a concave-convex surface, with the embossing depth not exceeding that of the shielding layer.

[0020] Compared with the prior art, firstly, the flexible solid-color melamine film of the present invention uniformly coats and adheres titanium dioxide and acrylic emulsion to the back of solid-color decorative paper. The titanium dioxide concentrated on the back of the solid-color decorative paper forms excellent hiding power, preventing the bottom from showing through and effectively covering small defects on the surface of fast-growing plywood. In addition to adhering titanium dioxide, the acrylic emulsion itself is also a white solid that can scatter light after curing, which can help titanium dioxide improve hiding power.

[0021] Secondly, the outer resin layer is designed to avoid the exposure of non-adhesive titanium dioxide, thereby minimizing the adverse effects of titanium dioxide on the flexible solid-color melamine film and other board structural layers or adhesive bonding, improving the composite strength. At the same time, the resin layer also has the effect of improving the hiding power.

[0022] Finally, the design of high-temperature short-time pressing of non-woven fabric substrate and plain decorative paper softens the plain decorative paper, effectively solving problems such as drying and cracking when pressing plain decorative paper with fast-growing plywood. The concave-convex surface design allows glue to flow in and fill, forming a structure similar to glue nails, which improves the bonding strength. By making the plain decoration flexible, the requirement for the flatness of the melamine surface of the substrate is reduced, solving the problem that the unevenness of the fast-growing plywood surface makes it difficult to press the melamine surface. This successfully achieves the application of melamine surface coating on the surface of fast-growing plywood.

[0023] Preferably, in step 1), the back coating liquid comprises the following raw materials in parts by weight: 40-60 parts titanium dioxide, 20-30 parts deionized water, 10-15 parts acrylic emulsion and 1-3 parts dispersant.

[0024] Preferably, the titanium dioxide is prepared by a silane coupling agent treatment step: titanium dioxide three-wash filter cake and deionized water are mixed at a mass ratio of 5:2-3 and slurryed into a uniform slurry. Then, 0.5-1.0% of silane coupling agent is added, and the mixture is thoroughly stirred until homogeneous. After drying, the mixture is finally pulverized by air jet milling to obtain a white titanium dioxide powder. The treated titanium dioxide exhibits better hiding power and structural stability, and its dispersibility is significantly improved.

[0025] Specifically, the titanium dioxide of this invention undergoes surface modification treatment with a silane coupling agent, resulting in a smaller particle size distribution and a longer settling time. The stereosiloxane structure formed by the silane treatment improves the original reflectivity and can shield ultraviolet radiation and block water molecule penetration, significantly reducing the risk of photodegradation of titanium dioxide in outdoor environments, improving hiding power and enhancing durability. The organic functional groups on the silane coupling agent react chemically with long-chain molecules in organic polymers to further form a cross-linked structure, enhancing structural stability and improving compatibility and bonding strength with resins, laying a good foundation for subsequent impregnation and coating with amino resins. In addition, the molecular structure of the silane coupling agent contains silicon, which can form a silicon oxide layer on the particle surface, improving the dispersibility of titanium dioxide and its dispersibility in organic matrices, and greatly shortening the dispersion time.

[0026] Preferably, the titanium dioxide content of the titanium dioxide is ≥95wt%, and the particle size of the titanium dioxide is 30-100nm. It has a good ability to scatter and absorb ultraviolet light, strong covering power, and antibacterial and anti-aging functions.

[0027] Preferably, the dispersant is an acrylic copolymer obtained by polymerization of acrylic acid, sodium styrene sulfonate and hydroxypropyl acrylate, which can better disperse titanium dioxide and make the titanium dioxide uniformly distributed in the cured back coating.

[0028] More preferably, the preparation operation of the back coating liquid is as follows: first mix the titanium dioxide, deionized water and acrylic emulsion, then add the dispersant, the stirring speed is 1100-1300 r / min, the stirring time is 50-100 min, and the dispersant is added after the titanium dioxide is fully wetted, so that it can be effectively adsorbed on the surface of the titanium dioxide to form a stable dispersion system, ensuring that the back coating liquid is fully stirred and uniform.

[0029] Preferably, the back coating liquid is applied to the back of the plain decorative paper by spraying, and the back coating is performed in two stages, with the first spraying amount being 6-12 g / m². 2 After spraying, the coating is dried. The first drying temperature is 140-150℃, and the first drying time is 10-18 seconds. The second spraying amount is 4-8 g / m². 2 After spraying, the coating is dried. The second drying temperature is 150-160℃ and the second drying time is 20-28s. The two sprayings make the back coating liquid more evenly distributed and form a gradient double-layer structure with better hiding power. The first drying allows the back coating liquid to be pre-cured to facilitate the second spraying, and the second drying allows the back coating liquid to be fully cured to prevent the back coating layer from falling off during subsequent impregnation.

[0030] Preferably, the base paper weight of the plain decorative paper is 70-90 g / m². 2The impregnation amount is 100-120%, the difference in impregnation amount between the front and back sides does not exceed 30%, the volatile content is 5.5-7.5%, the estimated degree of chemical reaction is 35-55%, and the formaldehyde release is ≤0.3mg / L. This design not only avoids the easy deformation of the produced flexible solid-color melamine film, which would affect subsequent lamination, but also supports the flexible design of this invention.

[0031] Preferably, in step 2), the urea-formaldehyde resin impregnation solution comprises urea-formaldehyde resin and amine-formaldehyde resin in a mass ratio of 3:0.8 to 1.2, with an impregnation amount of 55 to 65%, an impregnation speed of 30 to 40 m / min, a drying temperature of 120 to 130°C, and a drying time of 25 to 35 s.

[0032] By impregnating the back coating with urea-formaldehyde resin, the titanium dioxide is prevented from being exposed or worn off. However, the titanium dioxide back coating designed inside the film inevitably has a certain adverse effect on the bonding strength. This invention solves this problem by surface modification of titanium dioxide with silane coupling agent and the above-mentioned impregnation design. Specifically, the proportion of urea-formaldehyde resin is appropriately increased and the impregnation amount is increased to compensate for the adverse effect of the back coating designed inside the film on the bonding strength, while also further enhancing the hiding power.

[0033] Preferably, in step 3), the impregnation amount of the amine-formaldehyde resin is 45-55%, the speed is 30-40 m / min, the drying temperature is 130-140℃, and the drying time is 40-50 s.

[0034] Preferably, the amine-formaldehyde resin is a polyurethane-modified melamine resin. The polyurethane-modified melamine resin has significantly improved flexibility, which can enhance the flexibility of the flexible solid-color melamine film.

[0035] Preferably, in step 4), the basis weight of the nonwoven fabric substrate is 45–55 g / m³. 2 With a moisture content of 2.0-3.0%, it has a uniform and dense porous microstructure, which can help improve the covering power of the flexible solid-color melamine film of the present invention, while also improving air permeability and crack resistance, and avoiding surface quality defects during pressing.

[0036] Preferably, in step 4), the imprinting operation specifically involves: one side of the film material obtained in step 3) covered with a nonwoven fabric substrate is placed in contact with a wire mesh to form a textured surface. The surface of the wire mesh is coated with Teflon so that it will not adhere to the resin that permeates the nonwoven fabric during pressing. The mesh size is 80-120 mesh. The other side is placed in contact with a steel template. The texture depth of the steel template does not exceed 0.1 mm. Hot pressing is then performed at a pressure of 10-13 MPa, a temperature of 180-190°C, and a time of 15-20 seconds.

[0037] The present invention also discloses a flexible solid-color melamine film, which is made by the above-mentioned method for preparing flexible solid-color melamine film, comprising solid-color decorative paper, wherein a back coating is provided on one side of the solid-color decorative paper, and the back coating comprises uniformly distributed titanium dioxide particles.

[0038] The solid-color decorative paper and the back coating that have been laminated are then covered with a covering layer and a shielding layer in sequence;

[0039] A nonwoven fabric substrate is adhered to the outer side of the shielding layer on the same side as the back coating, or the shielding layer on the same side as the back coating encloses part or all of the nonwoven fabric substrate inside itself.

[0040] The flexible solid-color melamine film has a non-woven fabric substrate on one side, which is provided with a concave-convex surface with a concave-convex structure, and the concave depth of the concave-convex structure does not exceed the shielding layer.

[0041] The flexible solid-color melamine film has a flexible structure.

[0042] Preferably, the thickness of the flexible solid-color melamine film is 0.15 to 0.35 mm.

[0043] Specifically, the concave-convex structure includes multiple alternating convex structures arranged in a matrix pattern and concave structures located between the convex structures. After applying adhesive, the flexible solid-color melamine film can form an adhesive nail structure between itself and its adjacent structural layers in the board, ensuring a firm bond between the two.

[0044] The present invention also discloses a plain-colored ecological board, which includes a fast-growing plywood core board, wherein at least one outer surface of the fast-growing plywood core board is directly or indirectly coated with the above-mentioned flexible plain-colored melamine film.

[0045] Preferably, the flexible plain-colored melamine film is indirectly laminated to at least one outer surface of the fast-growing plywood core board, at least one partition is provided between the fast-growing plywood core board and the flexible plain-colored melamine film, and an environmentally friendly adhesive layer is provided between each structural layer. The environmentally friendly adhesive layer extends into and fills the concave structure on the surface of the flexible plain-colored melamine film to form adhesive nails.

[0046] Preferably, the fast-growing plywood core board has a thickness of 7–23 mm, a moisture content of 5.0–13.0%, a bonding strength ≥ 0.7 MPa, and a formaldehyde emission ≤ 0.050 mg / m³. 3 Specifically, it can be poplar plywood, engineered wood veneer plywood, eucalyptus plywood, eucalyptus-poplar plywood, etc.

[0047] Specifically, the poplar plywood is made of multiple layers of rotary-cut poplar veneers bonded together with environmentally friendly adhesives. The number of layers is odd, and the fiber directions of adjacent veneers are perpendicular to each other.

[0048] Preferably, the partition has a thickness of 0.8–1.2 mm and a density of 0.8–1.2 mg / cm³. 3 The moisture content is 4.0–9.0%, and the formaldehyde emission is ≤0.050 mg / m³. 3 .

[0049] This invention discloses a method for preparing the above-mentioned plain-colored ecological board, which includes at least the following steps:

[0050] 1) Using fast-growing plywood as the base material;

[0051] 2) Sand the substrate surface and apply an environmentally friendly adhesive, with an adhesive application rate of 100-120 g / m². 2 Then, the flexible plain-colored melamine film is laid on top, and cold pressing and hot pressing are performed in sequence to obtain plain-colored ecological boards.

[0052] This invention also discloses a method for preparing a plain-colored ecological board with partitions, comprising the following steps:

[0053] 1) At least one side of the fast-growing plywood is coated with an environmentally friendly adhesive, with an adhesive application rate of 100–120 g / m². 2 The adhesive-coated board surface is covered with partitions, and then cold-pressed and hot-pressed in sequence to obtain the substrate;

[0054] 2) Sand the substrate surface and apply an environmentally friendly adhesive, with an adhesive application rate of 100-120 g / m². 2 Then, the flexible plain-colored melamine film is laid on top, and cold pressing and hot pressing are performed in sequence to obtain plain-colored ecological boards.

[0055] Preferably, the sanding operation is as follows: the outer surface of the substrate is sanded with 240-grit sandpaper to improve the surface roughness and enhance the bonding strength between the substrate and the environmentally friendly adhesive.

[0056] Preferably, the environmentally friendly adhesive is a lignin adhesive, with no special restrictions; commercially available formaldehyde-free lignin adhesives are acceptable. These are mostly produced by separating and treating wood fiber raw materials or sulfate lignin using a mixed solution. This type of lignin adhesive does not contain formaldehyde and can achieve high bonding strength with a lower application rate, effectively ensuring the product quality and environmental friendliness of the plain-colored ecological board of this invention.

[0057] Preferably, the process parameters for cold pressing are: pressure 5-8 MPa, time 40-60 min.

[0058] By first cold pressing, the structural layers are initially shaped. At the same time, the cold pressing pressure ensures that the environmentally friendly adhesive flows into and fills the concave structure and penetrates evenly into the surface gaps of the substrate, ensuring full contact of the bonding surfaces and avoiding localized adhesive shortages. On the other hand, the initial cold pressing can squeeze out air bubbles in the bonding interface, reducing bubbling and delamination defects during later hot pressing.

[0059] Preferably, the hot pressing process parameters are: pressure 5-8 MPa, temperature 90-100℃, and time 8-10 min, which provides the heat curing temperature for the lignin environmentally friendly adhesive, ensuring the bonding strength of the adhesive layer and the quality of the board surface.

[0060] Preferably, the partition has a thickness of 0.8–1.2 mm and a density of 0.8–1.2 mg / cm³. 3 The moisture content is 4.0%–9.0%, and the formaldehyde emission is ≤0.050 mg / m³. 3 More preferably, the partition is a high-density fiberboard, which can further improve the flatness of the substrate and improve the crack resistance of the plain-colored ecological board.

[0061] The solid-color ecological board produced by this invention is flawless, opaque, highly flat, crack-resistant, environmentally friendly, wear-resistant, and scratch-resistant. The surface properties of the board are excellent, and it is also more cost-effective than existing ecological board products with a solid-color flat surface effect. Attached Figure Description

[0062] Figure 1 This is one of the structural schematic diagrams of the flexible solid-color triamine film of the present invention;

[0063] Figure 2 This is a second schematic diagram of the structure of the flexible solid-color triamine film of the present invention;

[0064] Figure 3 These are schematic diagrams of the solid-color ecological boards of Embodiments 1 to 3 of the present invention;

[0065] Figure 4 This is a schematic diagram of the solid color ecological board of Embodiment 4 of the present invention.

[0066] Figure Labels

[0067] A. Flexible solid-color melamine film;

[0068] 1. Shielding layer;

[0069] 2. Covering layer;

[0070] 3. Plain decorative paper;

[0071] 4. Back coating;

[0072] 5. Non-woven fabric substrate;

[0073] 6. Environmentally friendly adhesive layer; 601 adhesive nails;

[0074] 7. Fast-growing plywood;

[0075] 8. Partition. Detailed Implementation

[0076] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0077] Example 1

[0078] 1) Preparation of back coating liquid

[0079] Raw materials for preparation: 40kg titanium dioxide, 20kg deionized water, 10kg acrylic emulsion and 1kg dispersant.

[0080] Procedure: First, mix the titanium dioxide, deionized water and acrylic emulsion, then add the dispersant. Stir at 1100 r / min for 50 min.

[0081] The titanium dioxide is produced by mixing titanium dioxide filter cake (after three washes) and deionized water at a mass ratio of 5:2 to form a homogeneous slurry, then adding 0.5% silane coupling agent, stirring thoroughly, drying, and finally air-jet milling to obtain a white powder. The titanium dioxide content of the titanium dioxide is ≥95wt%, and the particle size of the titanium dioxide is 30nm.

[0082] The dispersant is an acrylic copolymer (CAS: 9003-01-4) obtained by polymerization of acrylic acid, sodium styrene sulfonate and hydroxypropyl acrylate.

[0083] 2) The above-mentioned back coating liquid is sprayed onto the back of the plain decorative paper 3 through a nozzle. The back coating is applied in two stages, with the first spray amount being 6g / m². 2 After spraying, the coating is dried. The first drying temperature is 140℃ and the first drying time is 10 seconds. The second spraying amount is 4g / m². 2 After spraying, the coating is dried. The second drying temperature is 150℃ and the second drying time is 20s, forming the back coating 4.

[0084] The base paper weight of the plain decorative paper 3 is 70 g / m². 2 The impregnation amount is 100%, the difference in impregnation amount between the front and back sides does not exceed 30%, the volatile content is 5.5%, the estimated degree of chemical oxidation is 35%, and the formaldehyde release is ≤0.3mg / L.

[0085] 3) Impregnate the membrane material obtained in step 2) with urea-formaldehyde resin impregnation solution, with an impregnation amount of 55% and an impregnation speed of 30m / min, and dry it at a drying temperature of 120℃ for 25s to form a covering layer 2 surrounding the membrane material in step 2).

[0086] The urea-formaldehyde resin impregnation solution is a mixture of urea-formaldehyde resin and amine-formaldehyde resin prepared at a mass ratio of 3:0.8.

[0087] 4) Coat both sides of the film material obtained in step 3) with amine-formaldehyde resin, with an impregnation amount of 45%, a speed of 30m / min, dry and cut, with a drying temperature of 130℃ and a drying time of 40s, to form a masking layer 1 covering the front and back of the film material in step 3) respectively.

[0088] 5) Prepare a weight of 45g / m 2 5. Nonwoven fabric substrate with a moisture content of 2.0%;

[0089] In step 4), a nonwoven fabric substrate 5 is laid on the outer side of the shielding layer 1 on the same side as the back coating layer 4 in the prepared film material. It is then sent into a hot press for hot pressing. The side covered with the nonwoven fabric substrate 5 is pressed into a concave-convex surface in contact with the wire mesh. The pressing depth does not exceed that of the shielding layer 1. The surface of the wire mesh is coated with Teflon and has a mesh size of 80. The other side is in contact with the steel template. The texture depth of the steel template does not exceed 0.1 mm. The hot pressing pressure is 10 MPa, the temperature is 180°C, and the time is 15 s, to obtain a flexible plain-colored melamine film A with a thickness of 0.15 mm.

[0090] Reference Figure 1 or Figure 2 The flexible solid-color melamine film A includes solid-color decorative paper 3, and a back coating 4 is provided on one side of the solid-color decorative paper 3. The back coating 4 includes uniformly distributed titanium dioxide particles.

[0091] The solid-color decorative paper 3 and the back coating 4 that have been laminated are then covered with a covering layer 2 and a shielding layer 1 in sequence;

[0092] A nonwoven fabric substrate 5 (such as...) is adhered to the outer side of the shielding layer 1 on the same side as the back coating 4. Figure 1 As shown), due to the compression of the wire mesh, the shielding layer 1 may slightly overflow the nonwoven fabric substrate 5, and after curing, the shielding layer 1 on the same side as the back coating layer will partially enclose the nonwoven fabric substrate 5 within itself (as shown). Figure 2 (As shown).

[0093] The flexible solid-color melamine film A has a non-woven fabric substrate on one side, which is provided with a concave-convex surface with a concave-convex structure, and the concave depth of the concave-convex structure does not exceed the shielding layer 1.

[0094] The concave-convex structure includes multiple alternating convex structures arranged according to a matrix rule and concave structures located between the convex structures;

[0095] The flexible solid-color melamine film A has a flexible structure.

[0096] 6) Prepare fast-growing plywood core board 7 (specifically poplar plywood) as the base material, with a thickness of 7mm, a moisture content of 5.0%, a bonding strength ≥0.7MPa, and a formaldehyde emission ≤0.050mg / m³. 3 ;

[0097] The poplar plywood is made of multiple layers of rotary-cut poplar veneers bonded together with an environmentally friendly adhesive (lignin-based formaldehyde-free adhesive). The number of layers is odd, and the fiber directions of adjacent veneers are perpendicular to each other.

[0098] 7) After sanding the substrate surface with 240-grit sandpaper, apply an environmentally friendly adhesive (lignin-based formaldehyde-free adhesive) to both sides, with an adhesive application rate of 100g / m². 2 Then, the flexible solid-color melamine film A obtained in step 5) is laid on top of each other.

[0099] First, perform cold pressing at a pressure of 5 MPa for 40 minutes.

[0100] Then, hot pressing is performed at a pressure of 5 MPa, a temperature of 90°C, and a time of 8 minutes. After cutting the edges, a plain-colored ecological board with double-sided decorative surface is obtained.

[0101] Reference Figure 3 The resulting plain-colored ecological board includes a fast-growing wood plywood core board 7. Flexible plain-colored melamine film A is laminated to both outer surfaces of the fast-growing wood plywood core board 7. An environmentally friendly adhesive layer 6 is provided between the fast-growing wood plywood core board 7 and the flexible plain-colored melamine film A. The environmentally friendly adhesive layer 6 extends into and fills the concave structure on the surface of the flexible plain-colored melamine film A to form adhesive nails 601.

[0102] Example 2

[0103] 1) Preparation of back coating liquid

[0104] Raw materials for preparation: 50kg titanium dioxide, 25kg deionized water, 13kg acrylic emulsion and 2kg dispersant.

[0105] Procedure: First, mix the titanium dioxide, deionized water and acrylic emulsion, then add the dispersant. Stir at 1200 r / min for 75 min.

[0106] The titanium dioxide is produced by mixing titanium dioxide filter cake (after three washes) and deionized water at a mass ratio of 5:2-3 to form a homogeneous slurry, then adding 0.75% silane coupling agent, stirring thoroughly, drying, and finally air-jet milling to obtain a white powder. The titanium dioxide content of the titanium dioxide is ≥95wt%, and the particle size of the titanium dioxide is 65nm.

[0107] The dispersant is an acrylic copolymer (CAS: 9003-01-4) obtained by polymerization of acrylic acid, sodium styrene sulfonate and hydroxypropyl acrylate.

[0108] 2) The above-mentioned back coating liquid is sprayed onto the back of the plain decorative paper 3 through a nozzle. The back coating is applied in two stages, with the first spraying amount being 9g / m². 2 After spraying, the coating is dried. The first drying temperature is 145℃ and the first drying time is 14 seconds. The second spraying amount is 6g / m². 2 After spraying, the coating is dried. The second drying temperature is 155℃ and the second drying time is 24s, forming the back coating 4.

[0109] The base paper weight of the plain decorative paper 3 is 80 g / m². 2 The impregnation amount is 110%, the difference in impregnation amount between the front and back sides does not exceed 30%, the volatile content is 6.5%, the estimated degree of chemical oxidation is 45%, and the formaldehyde release is ≤0.3mg / L.

[0110] 3) Impregnate the membrane material obtained in step 2) with urea-formaldehyde resin impregnation solution, with an impregnation amount of 60% and an impregnation speed of 35m / min, and dry it at a drying temperature of 125℃ for 30s to form a covering layer 2 surrounding the membrane material in step 2).

[0111] The urea-formaldehyde resin impregnation solution is a mixture of urea-formaldehyde resin and amine-formaldehyde resin prepared at a mass ratio of 3:1.

[0112] 4) Coat both sides of the film material obtained in step 3) with amine-formaldehyde resin, with an impregnation amount of 50%, a speed of 35m / min, dry and cut, with a drying temperature of 135℃ and a drying time of 45s, to form a masking layer 1 covering the front and back of the film material in step 3) respectively.

[0113] 5) Prepare a weight of 50g / m 2 5. Nonwoven fabric substrate with a moisture content of 2.5%;

[0114] In step 4), a nonwoven fabric substrate 5 is laid on the outer side of the shielding layer 1 on the same side as the back coating layer 4 in the prepared film material. It is then sent into a hot press for hot pressing. The side covered with the nonwoven fabric substrate 5 is pressed into a concave-convex surface in contact with the wire mesh. The pressing depth does not exceed that of the shielding layer 1. The surface of the wire mesh is coated with Teflon and has a mesh size of 100. The other side is in contact with the steel template. The texture depth of the steel template does not exceed 0.1 mm. The hot pressing pressure is 12 MPa, the temperature is 185℃, and the time is 18 s to obtain a flexible plain-colored melamine film A with a thickness of 0.25 mm.

[0115] Reference Figure 1 or Figure 2 The flexible solid-color melamine film A includes solid-color decorative paper 3, and a back coating 4 is provided on one side of the solid-color decorative paper 3. The back coating 4 includes uniformly distributed titanium dioxide particles.

[0116] The solid-color decorative paper 3 and the back coating 4 that have been laminated are then covered with a covering layer 2 and a shielding layer 1 in sequence;

[0117] A nonwoven fabric substrate 5 (such as...) is adhered to the outer side of the shielding layer 1 on the same side as the back coating 4. Figure 1 As shown), due to the compression of the wire mesh, the shielding layer 1 may slightly overflow the nonwoven fabric substrate 5, and after curing, the shielding layer 1 on the same side as the back coating layer will partially enclose the nonwoven fabric substrate 5 within itself (as shown). Figure 2 (As shown).

[0118] The flexible solid-color melamine film A has a non-woven fabric substrate on one side, which is provided with a concave-convex surface with a concave-convex structure, and the concave depth of the concave-convex structure does not exceed the shielding layer 1.

[0119] The concave-convex structure includes multiple alternating convex structures arranged according to a matrix rule and concave structures located between the convex structures;

[0120] The flexible solid-color melamine film A has a flexible structure.

[0121] 6) Prepare fast-growing plywood core board 7 (specifically, engineered wood veneer plywood) as the base material, with a thickness of 13mm, a moisture content of 9.0%, a bonding strength ≥ 0.7MPa, and a formaldehyde emission ≤ 0.050mg / m³. 3 ;

[0122] 7) After sanding the substrate surface with 240-grit sandpaper, apply an environmentally friendly adhesive (lignin-based formaldehyde-free adhesive) to both sides, with an adhesive application rate of 110g / m². 2 Then, the flexible solid-color melamine film A obtained in step 5) is laid on top of each other.

[0123] First, cold pressing is performed at a pressure of 7.5 MPa for 50 minutes.

[0124] Then, hot pressing is performed at a pressure of 7.5 MPa, a temperature of 95°C, and a time of 9 minutes. After cutting the edges, a plain-colored eco-board with double-sided decorative finish is obtained.

[0125] Reference Figure 3 The resulting plain-colored ecological board includes a fast-growing wood plywood core board 7. Flexible plain-colored melamine film A is laminated to both outer surfaces of the fast-growing wood plywood core board 7. An environmentally friendly adhesive layer 6 is provided between the fast-growing wood plywood core board 7 and the flexible plain-colored melamine film A. The environmentally friendly adhesive layer 6 extends into and fills the concave structure on the surface of the flexible plain-colored melamine film A to form adhesive nails 601.

[0126] Example 3

[0127] 1) Preparation of back coating liquid

[0128] Raw materials for preparation: 60kg titanium dioxide, 30kg deionized water, 15kg acrylic emulsion and 3kg dispersant.

[0129] Procedure: First, mix the titanium dioxide, deionized water and acrylic emulsion, then add the dispersant. Stir at 1300 r / min for 100 min.

[0130] The titanium dioxide is produced by mixing titanium dioxide filter cake (after three washes) and deionized water at a mass ratio of 5:2-3 to form a homogeneous slurry, then adding 1.0% silane coupling agent, stirring thoroughly, drying, and finally air-jet milling to obtain a white powder. The titanium dioxide content of the titanium dioxide is ≥95wt%, and the particle size of the titanium dioxide is 100nm.

[0131] The dispersant is an acrylic copolymer (CAS: 9003-01-4) obtained by polymerization of acrylic acid, sodium styrene sulfonate and hydroxypropyl acrylate.

[0132] 2) The above-mentioned back coating liquid is sprayed onto the back of the plain decorative paper 3 through a nozzle. The back coating is applied in two stages, with the first spraying amount being 12g / m². 2 After spraying, the coating is dried. The first drying temperature is 150℃ and the first drying time is 18 seconds. The second spraying amount is 8g / m². 2 After spraying, the coating is dried. The second drying temperature is 160℃ and the second drying time is 28s, forming the back coating 4.

[0133] The base paper weight of the plain decorative paper 3 is 90 g / m². 2 The impregnation amount is 120%, the difference in impregnation amount between the front and back sides does not exceed 30%, the volatile content is 7.5%, the estimated degree of chemical oxidation is 55%, and the formaldehyde release is ≤0.3mg / L.

[0134] 3) Impregnate the membrane material obtained in step 2) with urea-formaldehyde resin impregnation solution, with an impregnation amount of 65% and an impregnation speed of 40m / min, and dry it at a drying temperature of 130℃ for 35s to form a covering layer 2 surrounding the membrane material in step 2).

[0135] The urea-formaldehyde resin impregnation solution is a mixture of urea-formaldehyde resin and amine-formaldehyde resin prepared at a mass ratio of 3:1.2.

[0136] 4) Coat both sides of the film material obtained in step 3) with amine-formaldehyde resin, with an impregnation amount of 55%, a speed of 40m / min, dry and cut, with a drying temperature of 140℃ and a drying time of 50s, to form a masking layer 1 covering the front and back of the film material in step 3) respectively.

[0137] 5) Prepare a weight of 55g / m 2 5. Nonwoven fabric substrate with a moisture content of 3.0%;

[0138] In step 4), a nonwoven fabric substrate 5 is laid on the outer side of the shielding layer 1 on the same side as the back coating layer 4 in the prepared film material. It is then sent into a hot press for hot pressing. The side covered with the nonwoven fabric substrate 5 is pressed into a concave-convex surface in contact with the wire mesh. The pressing depth does not exceed that of the shielding layer 1. The surface of the wire mesh is coated with Teflon and has a mesh size of 120. The other side is in contact with the steel template. The texture depth of the steel template does not exceed 0.1 mm. The hot pressing pressure is 13 MPa, the temperature is 190°C, and the time is 20 s, to obtain a flexible plain-colored melamine film A with a thickness of 0.35 mm.

[0139] Reference Figure 1 or Figure 2 The flexible solid-color melamine film A includes solid-color decorative paper 3, and a back coating 4 is provided on one side of the solid-color decorative paper 3. The back coating 4 includes uniformly distributed titanium dioxide particles.

[0140] The solid-color decorative paper 3 and the back coating 4 that have been laminated are then covered with a covering layer 2 and a shielding layer 1 in sequence;

[0141] A nonwoven fabric substrate 5 (such as...) is adhered to the outer side of the shielding layer 1 on the same side as the back coating 4. Figure 1 As shown), due to the compression of the wire mesh, the shielding layer 1 may slightly overflow the nonwoven fabric substrate 5, and after curing, the shielding layer 1 on the same side as the back coating layer will partially enclose the nonwoven fabric substrate 5 within itself (as shown). Figure 2 (As shown).

[0142] The flexible solid-color melamine film A has a non-woven fabric substrate on one side, which is provided with a concave-convex surface with a concave-convex structure, and the concave depth of the concave-convex structure does not exceed the shielding layer 1.

[0143] The concave-convex structure includes multiple alternating convex structures arranged according to a matrix rule and concave structures located between the convex structures;

[0144] The flexible solid-color melamine film A has a flexible structure.

[0145] 6) Prepare fast-growing plywood core board 7 (specifically eucalyptus plywood) as the base material, with a thickness of 23mm, a moisture content of 13.0%, a bonding strength ≥0.7MPa, and a formaldehyde emission ≤0.050mg / m³. 3 ;

[0146] The eucalyptus plywood is made of multiple layers of rotary-cut eucalyptus veneers bonded together with an environmentally friendly adhesive (lignin-based formaldehyde-free adhesive). The number of layers is odd, and the fiber directions of adjacent veneers are perpendicular to each other.

[0147] 7) After sanding the substrate surface with 240-grit sandpaper, apply an environmentally friendly adhesive (lignin-based formaldehyde-free adhesive) to both sides, with an adhesive application rate of 120g / m². 2Then, the flexible solid-color melamine film A obtained in step 5) is laid on top of each other.

[0148] First, perform cold pressing at a pressure of 8 MPa for 60 minutes.

[0149] Then, hot pressing is performed at a pressure of 8MPa, a temperature of 100℃, and a time of 10min. After cutting the edges, a plain-colored ecological board with double-sided decorative surface is obtained.

[0150] Reference Figure 3 The resulting plain-colored ecological board includes a fast-growing wood plywood core board 7. Flexible plain-colored melamine film A is laminated to both outer surfaces of the fast-growing wood plywood core board 7. An environmentally friendly adhesive layer 6 is provided between the fast-growing wood plywood core board 7 and the flexible plain-colored melamine film A. The environmentally friendly adhesive layer 6 extends into and fills the concave structure on the surface of the flexible plain-colored melamine film A to form adhesive nails 601.

[0151] Example 4

[0152] 1) Preparation of back coating liquid

[0153] Raw materials for preparation: 50kg titanium dioxide, 25kg deionized water, 13kg acrylic emulsion and 2kg dispersant.

[0154] Procedure: First, mix the titanium dioxide, deionized water and acrylic emulsion, then add the dispersant. Stir at 1200 r / min for 75 min.

[0155] The titanium dioxide is produced by mixing titanium dioxide filter cake (after three washes) and deionized water at a mass ratio of 5:2-3 to form a homogeneous slurry, then adding 0.75% silane coupling agent, stirring thoroughly, drying, and finally air-jet milling to obtain a white powder. The titanium dioxide content of the titanium dioxide is ≥95wt%, and the particle size of the titanium dioxide is 65nm.

[0156] The dispersant is an acrylic copolymer (CAS: 9003-01-4) obtained by polymerization of acrylic acid, sodium styrene sulfonate and hydroxypropyl acrylate.

[0157] 2) The above-mentioned back coating liquid is sprayed onto the back of the plain decorative paper 3 through a nozzle. The back coating is applied in two stages, with the first spraying amount being 9g / m². 2 After spraying, the coating is dried. The first drying temperature is 145℃ and the first drying time is 14 seconds. The second spraying amount is 6g / m². 2 After spraying, the coating is dried. The second drying temperature is 155℃ and the second drying time is 24s, forming the back coating 4.

[0158] The base paper weight of the plain decorative paper 3 is 80 g / m². 2The impregnation amount is 110%, the difference in impregnation amount between the front and back sides does not exceed 30%, the volatile content is 6.5%, the estimated degree of chemical oxidation is 45%, and the formaldehyde release is ≤0.3mg / L.

[0159] 3) Impregnate the membrane material obtained in step 2) with urea-formaldehyde resin impregnation solution, with an impregnation amount of 60% and an impregnation speed of 35m / min, and dry it at a drying temperature of 125℃ for 30s to form a covering layer 2 surrounding the membrane material in step 2).

[0160] The urea-formaldehyde resin impregnation solution is a mixture of urea-formaldehyde resin and amine-formaldehyde resin prepared at a mass ratio of 3:1.

[0161] 4) Coat both sides of the film material obtained in step 3) with amine-formaldehyde resin, with an impregnation amount of 50%, a speed of 35m / min, dry and cut, with a drying temperature of 135℃ and a drying time of 45s, to form a masking layer 1 covering the front and back of the film material in step 3) respectively.

[0162] 5) Prepare a weight of 50g / m 2 5. Nonwoven fabric substrate with a moisture content of 2.5%;

[0163] In step 4), a nonwoven fabric substrate 5 is laid on the outer side of the shielding layer 1 on the same side as the back coating layer 4 in the prepared film material. It is then sent into a hot press for hot pressing. The side covered with the nonwoven fabric substrate 5 is pressed into a concave-convex surface in contact with the wire mesh. The pressing depth does not exceed that of the shielding layer 1. The surface of the wire mesh is coated with Teflon and has a mesh size of 100. The other side is in contact with the steel template. The texture depth of the steel template does not exceed 0.1 mm. The hot pressing pressure is 12 MPa, the temperature is 185℃, and the time is 18 s to obtain a flexible plain-colored melamine film A with a thickness of 0.25 mm.

[0164] Reference Figure 1 or Figure 2 The flexible solid-color melamine film A includes solid-color decorative paper 3, and a back coating 4 is provided on one side of the solid-color decorative paper 3. The back coating 4 includes uniformly distributed titanium dioxide particles.

[0165] The solid-color decorative paper 3 and the back coating 4 that have been laminated are then covered with a covering layer 2 and a shielding layer 1 in sequence;

[0166] A nonwoven fabric substrate 5 (such as...) is adhered to the outer side of the shielding layer 1 on the same side as the back coating 4. Figure 1 As shown), due to the compression of the wire mesh, the shielding layer 1 may slightly overflow the nonwoven fabric substrate 5, and after curing, the shielding layer 1 on the same side as the back coating layer will partially enclose the nonwoven fabric substrate 5 within itself (as shown). Figure 2 (As shown).

[0167] The flexible solid-color melamine film A has a non-woven fabric substrate on one side, which is provided with a concave-convex surface with a concave-convex structure, and the concave depth of the concave-convex structure does not exceed the shielding layer 1.

[0168] The concave-convex structure includes multiple alternating convex structures arranged according to a matrix rule and concave structures located between the convex structures;

[0169] The flexible solid-color melamine film A has a flexible structure.

[0170] 6) Fast-growing plywood 7 (specifically poplar plywood) has both sides coated with environmentally friendly adhesive, with an adhesive application rate of 110g / m². 2 Each of the glued boards is then covered with a partition board 8 (specifically, a high-density fiberboard);

[0171] First, cold pressing is performed at a pressure of 7.5 MPa for 50 minutes.

[0172] Then, hot pressing is performed at a pressure of 7.5 MPa, a temperature of 95°C, and a time of 9 minutes to obtain the substrate.

[0173] The fast-growing plywood core board 7 has a thickness of 13mm, a moisture content of 9.0%, a bonding strength ≥0.7MPa, and a formaldehyde emission ≤0.050mg / m³. 3 ;

[0174] The poplar plywood is made of multiple layers of rotary-cut poplar veneers bonded together with an environmentally friendly adhesive (lignin formaldehyde-free adhesive). The number of layers is odd, and the fiber directions of adjacent veneers are perpendicular to each other.

[0175] The partition 8 has a thickness of 1.0 mm and a density of 1.0 mg / cm³. 3 The moisture content is 6.5%, and the formaldehyde emission is ≤0.050mg / m³. 3 .

[0176] 7) After sanding the substrate surface with 240-grit sandpaper, apply an environmentally friendly adhesive (lignin-based formaldehyde-free adhesive) to both sides, with an adhesive application rate of 110g / m². 2 Then, the flexible solid-color melamine film A obtained in step 5) is laid on top of each other.

[0177] First, cold pressing is performed at a pressure of 7.5 MPa for 50 minutes.

[0178] Then, hot pressing is performed at a pressure of 7.5 MPa, a temperature of 95°C, and a time of 9 minutes. After cutting the edges, a plain-colored eco-board with double-sided decorative finish is obtained.

[0179] Reference Figure 4The resulting plain-colored ecological board includes a fast-growing wood plywood core board 7. A partition 8 is pressed and laminated on each of the outer surfaces of the two sides of the fast-growing wood plywood core board 7. A flexible plain-colored melamine film A is pressed and laminated on the outer surfaces of the partitions 8 on both sides. An environmentally friendly adhesive layer 6 is provided between each structural layer. The environmentally friendly adhesive layer 6 extends into and fills the concave structure on the surface of the flexible plain-colored melamine film A to form adhesive nails 601.

[0180] Comparative Example 1

[0181] Compared with Example 1, the 40 kg of titanium dioxide in this comparative example was divided into two equal parts, which were directly mixed with amine-formaldehyde resin and urea-formaldehyde resin respectively. Plain decorative paper was first impregnated with urea-formaldehyde resin impregnation solution mixed with titanium dioxide, and then coated with amine-formaldehyde resin mixed with titanium dioxide. The back coating liquid design and related process steps were eliminated; other operations were the same as in Example 1.

[0182] Observation results: Titanium dioxide is difficult to mix evenly with amine-formaldehyde resin and urea-formaldehyde resin, which easily clogs the mesh and requires frequent cleaning. It can still be made into a board for subsequent performance testing, but quality problems are prone to occur during pressing, and the board surface has uneven color and insufficient coverage.

[0183] Comparative Example 2

[0184] Compared with Example 1, this comparative example does not have a nonwoven fabric substrate 5; other operations are the same as in Example 1.

[0185] Observation results: The plain melamine film cannot achieve the ideal flexibility effect and still cannot completely cover the surface defects of the fast-growing plywood core board. There are quality problems such as wood splinter, see-through, wavy pattern, and dried flowers. In addition, there is a delamination phenomenon between the plain melamine film and the fast-growing plywood core board. This production process is not suitable and no subsequent performance test will be conducted.

[0186] Comparative Example 3

[0187] Compared with Example 3, the titanium dioxide used in this application is 70 kg; other operations are the same as in Example 3.

[0188] Observation results: The high proportion of titanium dioxide in the back coating liquid leads to material hardening and embrittlement, resulting in poor flexibility of the solid-color melamine film. Furthermore, during lamination, delamination occurs between the back coating and the nonwoven fabric, making this production process unsuitable. No further performance testing was conducted.

[0189] Comparative Example 4

[0190] Compared with Example 1, the spraying amount of the back coating liquid in step 2) of this comparative example is 5 g / m². 2 .

[0191] Observation results: It is still impossible to completely cover the surface defects of fast-growing plywood core boards, and there are quality problems such as wood grain, see-through patterns, and wavy patterns.

[0192] Comparative Example 5

[0193] Compared with Example 1, the urea-formaldehyde resin impregnation solution of this comparative example is prepared by mixing urea-formaldehyde resin and amine-formaldehyde resin at a mass ratio of 3:0.5.

[0194] Observation results: The bonding strength between the impregnated decorative paper and the non-woven fabric decreased, the surface properties of the product, such as abrasion and scratch resistance, were poor, and the formaldehyde release increased.

[0195] Performance testing

[0196] 1) The flexible solid-color melamine films prepared in Examples 1 to 4 and the comparative examples were tested, and the results are shown in the table below.

[0197]

[0198]

[0199] 2) The performance of the finished boards made in Examples 1 to 4 and Comparative Examples 1, 4 and 5 was tested, and the results are shown in the table below.

[0200]

[0201] As can be seen from the comparison between Comparative Example 1 and the Example, in this invention, titanium dioxide should not be directly mixed into urea-formaldehyde resin impregnation liquid and amine-formaldehyde resin raw materials, and then adhered to plain decorative paper 3 by impregnation or coating. The inventors conducted research and testing on this scheme and found that titanium dioxide is difficult to completely disperse in the resin system, and the final product shows local color unevenness. At the same time, since titanium dioxide is mixed in the resin system, after the resin is cured, some titanium dioxide will inevitably be exposed on the surface of the cured resin, which has an adverse effect on the surface adhesion of the resin and is also prone to quality problems during pressing. In addition, the distribution of titanium dioxide in the resin layer is relatively dispersed, with insufficient concentration and poor hiding power.

[0202] Based on the disclosure and teachings of the foregoing specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present invention should also fall within the protection scope of the claims of the present invention. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the present invention.

Claims

1. A flexible solid-color melamine film, characterized in that, Its preparation process includes the following steps: 1) Apply a back coating liquid to the back of plain decorative paper, dry it to form a back coating layer, wherein the back coating liquid contains at least titanium dioxide and acrylic emulsion; 2) Impregnate with urea-formaldehyde resin impregnation solution, dry, and form a covering layer surrounding the film material in step 1); 3) Coat both sides with amine-formaldehyde resin and dry to form a shielding layer that at least covers the front and back sides of the film material in step 2); 4) A non-woven fabric substrate is laid on the outside of the shielding layer on the same side as the back coating, and then embossed to form a concave-convex surface, with the embossing depth not exceeding that of the shielding layer.

2. The flexible solid-color melamine film according to claim 1, characterized in that, In step 1), the back coating liquid contains the following raw materials in parts by weight: 40-60 parts titanium dioxide, 20-30 parts deionized water, 10-15 parts acrylic emulsion and 1-3 parts dispersant; The titanium dioxide is prepared by a silane coupling agent treatment step: titanium dioxide three-wash filter cake and deionized water are mixed in a mass ratio of 5:2 to 3 and slurryed into a uniform slurry. Then, 0.5 to 1.0% of silane coupling agent is added, and the mixture is stirred thoroughly and evenly. After drying, the mixture is finally pulverized by airflow to obtain white titanium dioxide powder. The titanium dioxide content of the titanium dioxide is ≥95wt%, and the particle size of the titanium dioxide is 30-100nm. The preparation operation of the back coating liquid is as follows: first mix the titanium dioxide, deionized water and acrylic emulsion, then add the dispersant, the stirring speed is 1100-1300r / min, and the stirring time is 50-100min. The back coating liquid is applied to the back of the plain decorative paper by spraying. The back coating is applied in two stages, with the first spraying amount being 6-12 g / m². 2 After spraying, the coating is dried. The first drying temperature is 140-150℃, and the first drying time is 20-28 seconds. The second spraying amount is 4-8 g / m². 2 After spraying, dry the coating. The second drying temperature is 150-160℃ and the second drying time is 10-18 seconds. The base paper weight of the plain decorative paper is 70-90 g / m². 2 The impregnation amount is 100-120%, the difference in impregnation amount between the front and back sides does not exceed 30%, the volatile content is 5.5-7.5%, the estimated degree of chemical oxidation is 35-55%, and the formaldehyde release is ≤0.3mg / L.

3. The flexible solid-color melamine film according to claim 1 or 2, characterized in that, In step 2), the urea-formaldehyde resin impregnation solution contains urea-formaldehyde resin and amine-formaldehyde resin in a mass ratio of 3:0.8 to 1.2, with an impregnation amount of 55% to 65%, an impregnation speed of 30 to 40 m / min, a drying temperature of 120 to 130°C, and a drying time of 25 to 35 s. In step 3), the impregnation amount of the amine-formaldehyde resin is 45-55%, the speed is 30-40 m / min, the drying temperature is 130-140℃, and the drying time is 40-50 s. The amine-aldehyde resin is a polyurethane-modified melamine resin.

4. The flexible solid-color melamine film according to claim 1 or 2, characterized in that, In step 4), the basis weight of the nonwoven fabric substrate is 45–55 g / m³. 2 Moisture content 2.0–3.0%; The specific operation of the imprinting is as follows: In step 3), the side of the film material with the non-woven fabric substrate is laid in contact with the wire mesh to form an uneven surface. The surface of the wire mesh is coated with Teflon and has a mesh size of 80 to 120. The other side is in contact with the steel template. The texture depth of the steel template does not exceed 0.1 mm. Hot pressing is performed at a pressure of 10 to 13 MPa, a temperature of 180 to 190°C, and a time of 15 to 20 seconds.

5. A flexible solid-color melamine film, characterized in that, The invention includes plain decorative paper, one side of which has a back coating, the back coating comprising uniformly distributed titanium dioxide particles. The composite solid-color decorative paper and back coating are then sequentially covered with a covering layer and a shielding layer; The outer side of the shielding layer on the same side as the back coating layer is adhered with a non-woven fabric substrate, or the shielding layer on the same side as the back coating layer encloses part or all of the non-woven fabric substrate within itself. The flexible solid-color melamine film has a non-woven fabric substrate on one side, which is provided with a concave-convex surface with a concave-convex structure, and the concave depth of the concave-convex structure does not exceed the shielding layer. The flexible solid-color melamine film has a flexible structure.

6. A plain-colored eco-friendly board, characterized in that, The plain-colored ecological board includes a fast-growing plywood core board, and at least one outer surface of the fast-growing plywood core board is directly or indirectly laminated with the flexible plain-colored melamine film as described in any one of claims 1 to 5.

7. The plain-colored ecological board according to claim 6, characterized in that, The flexible plain-colored melamine film is indirectly laminated to at least one outer panel of the fast-growing wood plywood core board. At least one partition is provided between the fast-growing wood plywood core board and the flexible plain-colored melamine film. An environmentally friendly adhesive layer is provided between each structural layer. The environmentally friendly adhesive layer extends into and fills the concave structure on the surface of the flexible plain-colored melamine film to form adhesive nails. The thickness of the flexible solid-color melamine film is 0.15–0.35 mm; The fast-growing plywood core has a thickness of 7–23 mm, a moisture content of 5.0–13.0%, a bonding strength ≥0.7 MPa, and a formaldehyde emission ≤0.050 mg / m³. 3 .

8. A method for preparing a plain-colored ecological board, characterized in that, It includes the following steps: 1) Using fast-growing plywood as the base material, Alternatively, at least one side of the fast-growing plywood is coated with an environmentally friendly adhesive, with an adhesive application rate of 100–120 g / m². 2 The glued board surface is covered with partitions, and then cold-pressed and hot-pressed in sequence to serve as the base material; 2) Sand the substrate surface and apply an environmentally friendly adhesive, with an adhesive application rate of 100-120 g / m². 2 Then, a flexible plain-colored melamine film as described in any one of claims 1 to 5 is laid on it, and cold pressing and hot pressing are performed in sequence to obtain a plain-colored ecological board.

9. The method for preparing the plain-colored ecological board according to claim 8, characterized in that, In steps 1) and 2), the process parameters for cold pressing are: pressure 5-8 MPa, time 40-60 min; The hot pressing process parameters are: pressure 5-8 MPa, temperature 90-100℃, and time 8-10 min.

10. The method for preparing the plain-colored ecological board according to claim 8 or 9, characterized in that, The environmentally friendly adhesive is a lignin-based formaldehyde-free adhesive; The outer surface of the substrate is sanded with 240-mesh abrasive belt; The partition plate has a thickness of 0.8–1.2 mm and a density of 0.8–1.2 mg / cm³. 3 The moisture content is 4.0%–9.0%, and the formaldehyde emission is ≤0.050 mg / m³. 3 .

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