A non-formaldehyde veneer and a method for manufacturing the same

Abstract

The present application relates to a kind of formaldehyde-free veneer and its preparation method.Formaldehyde-free veneer is made of formaldehyde-free substrate and improved formaldehyde-free veneer paper by flat paste process.Formaldehyde-free substrate includes substrate layer, balance layer and hard bottom coating, and its preparation involves multiple processes and uses innovative formaldehyde-free adhesive.The preparation method of formaldehyde-free veneer provided by the present application includes six steps of formaldehyde-free adhesive preparation, preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate, formaldehyde-free plywood and formaldehyde-free blockboard substrate making, formaldehyde-free substrate hardening treatment, high surface performance formaldehyde-free paper preparation and formaldehyde-free veneer composite making.The present application combines formaldehyde-free adhesive technology, high polymer surface treatment technology and low-temperature bonding low-energy production technology of wood-based panel, and the production process is advanced and efficient.In each process, through precise parameter control and advanced equipment and technology application, the stability and consistency of product quality in large-scale production process are ensured, and a new type of formaldehyde-free energy-saving veneer is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of formaldehyde-free artificial board manufacturing, in particular to a formaldehyde-free veneered board and a preparation method thereof. BACKGROUND

[0002] The impregnated film paper veneered artificial board is the most widely used indoor decoration material in the field of home decoration, and its environmental protection performance attracts the attention of consumers. The environmental protection performance of the conventional impregnated film paper veneered artificial board on the market can generally reach E0 level or even ENF level, but the formaldehyde emission amount is only the value measured under the condition of normal temperature 23℃ and humidity 50%. With the increase of temperature, the formaldehyde emission amount of the product using urea-formaldehyde adhesive system increases by several times, resulting in a 3-10 times increase of the formaldehyde emission amount of the board under the condition of summer or use of warm air in the north, a decrease of the indoor air quality, and an impact on people's health.

[0003] The impregnated film paper veneered artificial board uses artificial board as the base material and impregnated film paper as the veneer material, and is formed by high temperature and high pressure pressing. Although the current adhesive level develops rapidly, and three-aldehyde glue, lignin glue, and even formaldehyde-free soybean glue are developed for product manufacturing, the three-aldehyde glue and lignin glue contain formaldehyde, and the soybean glue cannot be used in the whole production process of the impregnated film paper veneered artificial board due to poor cohesiveness and fast drying of the glue, so that the real formaldehyde-free wood-based single board cannot be achieved. Especially the veneered board using impregnated paper as the veneer material, because the three-aldehyde glue is generally used as the impregnated material for the impregnated paper at present, the threshold of formaldehyde-free board cannot be reached.

[0004] Super-low formaldehyde veneered boards using Boli paper, Huali paper, and pre-painted paper as the veneer material instead of impregnated film paper are successively introduced in Europe, the United States, Japan, etc., but these veneer materials have low surface hardness, and the veneered boards prepared therefrom have defects such as poor scratch resistance and wear resistance, which easily cause scratches during subsequent processing of furniture board pieces, affect the appearance and service life, and cannot be widely used as decorative materials for indoor decoration.

[0005] Some European home brands pay great attention to the environmental protection and energy saving of furniture production process, and prepare "formaldehyde-free veneered boards" using super-low formaldehyde artificial boards as the base material and pre-painted paper as the veneer material, but the base material is limited to particle boards, and cannot be realized on plywood and blockboard. In addition, the surface wear resistance, scratch resistance, hardness, and other properties of the product are extremely poor, and the color and texture are single, so that the product can only be used for flat products, and cannot be accepted by consumers in the domestic market. At the same time, due to the poor surface properties, scratches often occur during subsequent processing, resulting in a high rejection rate of the board pieces, and the product cannot be widely promoted in many furniture processing factories. SUMMARY

[0006] The present application aims to provide a formaldehyde-free veneer panel and a preparation method thereof to solve the problems that the existing impregnated paper veneer panel cannot add formaldehyde and the surface of the pre-impregnated paper veneer panel is not wear-resistant and scratch-resistant.

[0007] The present application combines formaldehyde-free adhesive technology, polymer surface treatment technology, and low-temperature bonding and low-energy production technology of artificial boards to prepare a formaldehyde-free, high-surface-performance, and low-carbon-emission paper veneer artificial board, and provides a veneer artificial board with no formaldehyde addition and suitable for custom production lines and a preparation method thereof, which uses formaldehyde-free board core, core board, and balancing layer as raw materials, and uses formaldehyde-free adhesive water-based polyurethane adhesive as a special adhesive to prepare formaldehyde-free plywood and formaldehyde-free blockboard. The present application provides a preparation process of a formaldehyde-free veneer panel, which uses formaldehyde-free blockboard and plywood as base materials, surface treatment pre-impregnated paper veneer material, and polyurethane adhesive flat lamination process to complete the compounding of the base plate and the veneer layer to prepare a formaldehyde-free paper veneer artificial board. In addition, the present application uses low-temperature and low-pressure process in the production process to reduce the use of energy consumption and has a large energy-saving effect.

[0008] The present application provides a formaldehyde-free veneer panel, which specifically comprises: formaldehyde-free base plate and formaldehyde-free veneer paper.

[0009] The formaldehyde-free base plate comprises formaldehyde-free plywood and formaldehyde-free blockboard.

[0010] The formaldehyde-free veneer paper is improved pre-impregnated paper.

[0011] The formaldehyde-free veneer panel is prepared by compounding the formaldehyde-free base plate and the formaldehyde-free veneer paper using a flat lamination process.

[0012] The formaldehyde-free base plate avoids the release of formaldehyde in the use process, providing a healthier guarantee for the indoor environment. The improved pre-impregnated paper also does not contain formaldehyde, and cooperates with the formaldehyde-free base plate to eliminate the source of formaldehyde from the two main parts of the veneer panel. This makes the entire veneer panel meet strict environmental protection standards, helps to reduce indoor air pollution, and is a green and environmentally friendly decorative material. The formaldehyde-free veneer paper is improved pre-impregnated paper, which can provide various decorative effects, simulate various wood textures, stone textures, etc., and meet the needs of different decoration styles. The formaldehyde-free plywood and formaldehyde-free blockboard as the base plate have good strength and stability. The plywood is made of multiple thin plates bonded together, and the blockboard has a stable internal structure, which can provide a solid foundation for the veneer panel and make it have good deformation resistance. When subjected to certain external forces, such as daily collisions and extrusions, it is not easy to be damaged, ensuring the quality and durability of the veneer panel.

[0013] The flat lamination process can tightly combine the formaldehyde-free substrate and the formaldehyde-free decorative paper. The process can ensure high bonding between the decorative paper and the substrate, and reduce quality problems such as hollowing and blistering. In the long-term use process, the surface flatness of the decorative panel can be well maintained, and deformation or peeling of the decorative paper will not occur due to poor bonding, thereby improving the service life and aesthetic appearance of the decorative panel.

[0014] As preferred, the formaldehyde-free substrate specifically comprises: a substrate layer, a balancing layer and a hardening primer layer;

[0015] The substrate layer is one or two formaldehyde-free blockboard cores or eucalyptus core boards prepared by gluing, assembling, cold pressing, core repairing, hot pressing, thickness setting, sanding, polishing process using formaldehyde-free adhesive; the moisture content of the blockboard core is 5-8%, and the moisture content of the eucalyptus core board is 6-12%

[0016] The balancing layer is a formaldehyde-free added poplar bleached veneer or high-density fiberboard.

[0017] The sanding smoothness of the hardening primer layer is Ra 0.3-0.5, and the surface hardness reaches 3-5H.

[0018] The substrate layer is prepared using formaldehyde-free adhesive, which further ensures the formaldehyde-free characteristics of the entire substrate. In an indoor environment, the release of formaldehyde is mainly from chemical substances such as adhesives, and the use of formaldehyde-free adhesive avoids this potential source of pollution, ensuring the indoor air quality and being very beneficial to the health of the occupants.

[0019] It is prepared by gluing, assembling, cold pressing, core repairing, hot pressing, thickness setting, sanding, polishing and other processes. These complex process steps ensure the quality of the substrate layer. The hot pressing process can make the internal structure of the board more compact, improve its strength and stability; the thickness setting sanding and polishing process can make the board surface more smooth, providing a good foundation for the subsequent attachment of the balancing layer and the hardening primer layer.

[0020] The moisture content of the blockboard core and the eucalyptus core board is strictly controlled, the moisture content of the blockboard core is 5-8%, and the moisture content of the eucalyptus core board is 6-12%. The appropriate moisture content can prevent deformation, cracking and other problems of the board due to changes in moisture content during use. Under different environmental humidity conditions, this moisture content control can maintain good stability of the board and prolong its service life.

[0021] The balancing layer uses formaldehyde-free added poplar bleached veneer or high-density fiberboard, which is in line with the formaldehyde-free concept of the substrate layer. The entire substrate meets the environmental protection requirements from the inside to the outside, and the formaldehyde-free added material avoids pollution of the indoor environment caused by the release of chemicals, and the environmental protection characteristics are more advantageous.

[0022] The poplar bleached veneer has good decorative property, and the color is relatively light, which can provide a relatively uniform base color for the veneered panel, facilitating subsequent processing and decoration. At the same time, the high-density fiberboard has high density and strength, which can enhance the overall structural performance of the substrate, making the substrate more solid and durable, and the ability to resist deformation and external damage is stronger.

[0023] The surface hardness of the hardening primer reaches 3-5H, and the relatively high hardness enables the veneered panel to resist scratches and wear in daily use. After sanding, the smoothness Ra is 0.3-0.5, which means that the surface of the primer is very smooth, not only improving the appearance quality of the veneered panel and making it look more delicate, but also being more convenient in cleaning. The smooth surface is not easy to get dust and stains, and even if there are stains, it is easier to clean, reducing the difficulty and frequency of cleaning.

[0024] The present application provides a preparation method of formaldehyde-free veneered panel, and the specific process flow includes:

[0025] S1 preparation of formaldehyde-free adhesive;

[0026] S2 preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate;

[0027] S3 preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate;

[0028] S4 hardening treatment of formaldehyde-free substrate;

[0029] S5 preparation of formaldehyde-free paper with high surface performance;

[0030] S6 composite preparation of formaldehyde-free veneered panel.

[0031] The preparation of formaldehyde-free adhesive is the key starting point of the whole production of formaldehyde-free veneered panel. Traditional adhesives are often the main source of formaldehyde release, and by specially preparing formaldehyde-free adhesives, formaldehyde is eliminated from the source into the veneered panel production link, which is crucial for producing environmentally friendly veneered panels. This adhesive can ensure that there is no formaldehyde pollution in the subsequent substrate preparation and the whole veneered panel production process due to the adhesive, so that the final product meets strict environmental protection standards and is conducive to improving indoor air quality.

[0032] The preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrates is an important step in ensuring the quality of the veneered panel. Through this step, key factors such as wood quality, fiber direction, and board density of the substrate can be controlled. In the preparation of plywood substrates, selecting high-quality wood and arranging the synthesis of veneers reasonably can make the plywood have good mechanical properties; for blockboard, the splicing and arrangement of the core material can be optimized to improve its flatness and stability. The preparation process of formaldehyde-free plywood and formaldehyde-free blockboard substrates ensures that the substrate itself does not contain formaldehyde, which is fully consistent with the formaldehyde-free positioning of the veneered panel. This consistency makes the entire veneered panel more reliable in terms of environmental performance, avoiding the harm to the indoor environment caused by formaldehyde release from the substrate. Moreover, the formaldehyde-free substrate will not react with other formaldehyde-free materials to release formaldehyde during subsequent processing and use, ensuring the long-term environmental performance of the veneered panel.

[0033] During the production of formaldehyde-free plywood and formaldehyde-free blockboard substrates, the formaldehyde-free plywood and formaldehyde-free blockboard are reasonably combined and processed to form a substrate with good structural integrity. Through a specific pressing process, the plywood and blockboard can be tightly combined to compensate for possible structural defects. The multi-layer structure of plywood and the core-veneer structure of blockboard work together to enhance the substrate's resistance to deformation, allowing it to maintain good flatness and stability under different temperature and humidity conditions, providing a solid foundation for the long-term use of the veneered panel.

[0034] The surface hardness of the formaldehyde-free substrate after hardening treatment is significantly improved. After hardening treatment, the substrate can better resist friction and external forces, reducing surface scratches and wear, maintaining the appearance and service life of the veneered panel. Hardening treatment not only increases hardness but also improves the stability of the substrate's surface. It can make the surface more flat and smooth, and reduce surface deformation caused by external factors during long-term use. This stable surface provides better conditions for subsequent veneer paper compounding, allowing the veneer paper to be more tightly and uniformly attached to the substrate, avoiding quality problems such as blistering and delamination.

[0035] The preparation of formaldehyde-free paper with high surface performance not only continues the environmental concept of formaldehyde-free, ensuring that the veneered panel will not introduce formaldehyde during the veneering process, but also has excellent decorative performance. It can simulate the texture and color of various natural materials through printing and impregnation processes to meet the individualized decoration needs of different consumers. High-surface-performance formaldehyde-free paper also has advantages in strength and stain resistance. It has a certain tear resistance and is not easily damaged during processing and installation. At the same time, it can be specially treated to improve its stain resistance, making the veneered panel easier to clean and maintain in daily use.

[0036] In the composite production process of formaldehyde-free veneer, the formaldehyde-free substrate and high-surface-performance formaldehyde-free paper are combined together through the flat lamination process, fully utilizing the advantages of both. The strength and stability of the substrate and the decorative and environmental performance of the veneer are integrated, forming a veneer that is both beautiful and practical. This composite structure enables the veneer to be used in various environments, whether as a wall decoration or a furniture surface decoration, meeting the requirements. The composite production process can realize large-scale and high-efficiency production. Through the flat lamination process, the veneer can be quickly and accurately laminated with the substrate, ensuring product quality while improving production efficiency. This helps to reduce production costs, making the formaldehyde-free veneer more competitive in the market, and enabling it to be more widely promoted and applied, meeting the growing market demand for environmentally friendly decorative materials.

[0037] As a preferred, the formaldehyde-free adhesive is a modified acrylic resin adhesive, and the preparation of the formaldehyde-free adhesive is the preparation of a modified acrylic resin, and the specific steps include:

[0038] S11 Preparation of raw materials: 20-25 parts of acrylic monomer, 50-60 parts of acrylic ester monomer, 10-16 parts of hydroxyl functional body, 5-10 parts of polyvinyl alcohol, 2-4 parts of emulsifier, 0.02-0.06 parts of initiator, 60-90 parts of deionized water;

[0039] The acrylic monomer is one of acrylic acid, methyl acrylate or ethyl acrylate, or a mixture of two;

[0040] The acrylic ester monomer is obtained by ester exchange reaction of methyl acrylate and isopentyl glycol;

[0041] S12 Preparation of modified acrylic resin emulsion:

[0042] First, mix the acrylic monomer, acrylic ester monomer and deionized water, then add the hydroxyl functional body, polyvinyl alcohol, emulsifier and initiator, and continuously react at 40-80°C under nitrogen protection at a stirring speed of 300-800 revolutions per minute for 2-6 hours to prepare the modified acrylic resin emulsion;

[0043] S13 Preparation of modified acrylic resin adhesive:

[0044] Use the prepared modified acrylic resin emulsion as the main body, add a part of flour as the filler, and supplement with a certain amount of moisture adjusting material calcium chloride or magnesium chloride, and mix for 10-15 minutes at a high speed of 500-3000 revolutions per minute to obtain the modified acrylic resin adhesive. Modified acrylic resin emulsion: flour: moisture adjusting material = 80-100:20-25:0.5-1.

[0045] The adhesive prepared by the process has high performance and great innovation. The modified acrylic resin emulsion is used as the main body. The acrylic resin emulsion has good adhesive performance and flexibility. It can form a uniform glue film on the surface of different materials, and can well adapt to the surface microstructure of wood and other materials, thereby providing good gluing effect. The selection of the acrylic monomer and the acrylic ester monomer is targeted. The acrylic monomer, such as acrylic acid, methyl acrylate or ethyl acrylate, and the acrylic ester monomer obtained by ester exchange reaction can provide a good polymerization basis to form a polymer with a suitable molecular weight and molecular structure, thereby giving the adhesive good adhesive performance and flexibility. The addition of the hydroxyl functional body can participate in the subsequent cross-linking reaction and increase the cohesive force and bonding strength of the adhesive. The addition of polyvinyl alcohol can thicken and stabilize the emulsion, making the performance of the adhesive more stable during storage and use. The ratio of the raw materials is optimized to ensure that the modified acrylic resin emulsion with excellent performance is formed during the reaction.

[0046] A part of the flour is added as a filler. The flour can increase the volume of the adhesive, reduce the cost, and also improve the rheological properties of the adhesive to some extent, making it easier to operate during the gluing process. The viscosity of the adhesive can be more moderate, neither too thin to flow nor too thick to be difficult to apply.

[0047] A certain amount of humidity adjusting material is added. The humidity adjusting material can adjust the humidity of the surrounding environment of the adhesive, which is helpful to maintain the appropriate moisture content of the adhesive during the curing process, avoiding the influence of the gluing effect caused by the rapid loss or excessive absorption of water. In a dry environment, the humidity adjusting material can prevent the adhesive from drying too quickly and cracking. In a humid environment, it can prevent the adhesive from absorbing too much water and becoming soft and reducing adhesion.

[0048] The reaction is carried out under nitrogen protection, avoiding the interference of oxygen on the polymerization reaction, reducing the occurrence of side reactions, and being conducive to the formation of high-quality modified acrylic resin emulsion. The reaction temperature is 40-80℃, the stirring speed is 300-800 revolutions per minute, and the reaction time is 2-6 hours. Suitable temperature and stirring speed can ensure that the monomers are fully polymerized to form polymers with reasonable molecular weight distribution. Too high temperature may cause the polymerization reaction to be too fast, resulting in polymers with too large or too small molecular weight, affecting the performance of the adhesive. Too low temperature will slow down the reaction and reduce the efficiency. Suitable stirring speed can make the reactants fully mixed and promote uniform reaction. High-speed stirring can make the components fully mixed and ensure that the modified acrylic resin emulsion, flour and humidity adjusting material can form a good synergistic effect. Uniform mixing can avoid the problem of inconsistent gluing strength caused by uneven composition, making the adhesive stable in performance during the whole use process.

[0049] Due to reasonable formula design and sufficient mixing process, the prepared formaldehyde-free adhesive has advantages in gluing performance; compared with the formaldehyde-free adhesive available on the market, the formaldehyde-free adhesive is environmentally friendly, can better adapt to the surface characteristics of the substrate and the facing material, provide more uniform gluing strength, reduce cost and improve economic value.

[0050] As preferred, the formaldehyde-free plywood and formaldehyde-free blockboard substrate is prepared, and the specific steps include:

[0051] S21: preparing materials: formaldehyde-free adhesive and board core material;

[0052] The formaldehyde-free adhesive is a modified acrylic resin adhesive;

[0053] The board core material is one or two formaldehyde-free blockboard cores or eucalyptus core boards; the moisture content of the blockboard core is 5-8%, and the moisture content of the eucalyptus core board is 6-12%;

[0054] S22: gluing and assembling: the board core material is assembled according to the design scheme, the formaldehyde-free adhesive is applied at a quantity of 160-170 g / m², and the gluing time is controlled within 40-60 minutes;

[0055] S23: cold pressing: the cold pressing time is set to 40-80 minutes, and the pressure is 0.6-0.9 MPa;

[0056] S24: core repairing: cutting off the overlap and filling the core gap;

[0057] S25: hot pressing: the temperature is 120-130℃, the time is 20-60 minutes, the pressure is 0.6-0.9 MPa, the hot pressing is performed to the moisture content of 7-9% in the blank board, and the moisture content deviation is 1-2%; the blank board is hot pressed within 12 hours after cold pressing;

[0058] S26: thickness setting and sanding: the 60 and 120 mesh combined sand belt is selected, the sanding is performed to the specified thickness of 15-16 mm, the thickness deviation in the board is within 0.2 mm, and the surface smoothness is Ra1.5-1.7;

[0059] S27: putty scraping: filling the core gap on the board surface;

[0060] S28: edge cutting: obtaining the formaldehyde-free plywood and formaldehyde-free blockboard substrate by one-time edge cutting, and the cutting amount is 20-30 mm;

[0061] S29: aging: the aging cycle is 5-8 days, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate is obtained.

[0062] In the preparation process of the formaldehyde-free plywood and the formaldehyde-free blockboard substrate, by reasonably controlling the gluing amount, gluing time, cold pressing time and pressure and other parameters, the gluing quality of the board is improved, the gluing between the core materials is more firm, and the quality problems such as delamination and cracking are reduced; the performance of the board is more stable during subsequent processing and use; due to the good gluing quality, the board is not easy to deform, damage and other conditions during subsequent processes such as hot pressing, sanding and edge cutting.

[0063] The gluing amount and time of the process are determined according to the properties of the formaldehyde-free adhesive (modified acrylic resin glue) used and the properties of the core material (formaldehyde-free blockboard core and eucalyptus core board), the gluing amount is 160-170 g / m², and the gluing time is controlled within 40-60 minutes; suitable gluing amount and time can ensure that the adhesive is fully distributed on the surface of the core material, and a good gluing effect can be formed during the subsequent cold pressing process; too much gluing amount will cause the adhesive to overflow, affecting the appearance and quality of the board; too little gluing amount will not be firm; too long gluing time will cause the adhesive to partially dry during the gluing process, affecting the gluing effect; too short gluing time will not be evenly distributed. The cold pressing time of the process is set to 40-80 minutes, and the pressure is 0.6-0.9 MPa; the parameters of the cold pressing time and pressure are determined according to the moisture content of the core material (the moisture content of the blockboard core is 5-8%, and the moisture content of the eucalyptus core board is 6-12%) and the curing characteristics of the adhesive; suitable cold pressing time and pressure can make the core material fully contact during gluing, exclude air, and make the adhesive cure under suitable pressure and time conditions to form a firm gluing connection; too short cold pressing time or too small pressure will not be firm; too long cold pressing time or too large pressure will damage the core material and affect the performance of the board.

[0064] The cold pressing parameters of the process match the properties of the formaldehyde-free adhesive (modified acrylic resin glue). Suitable time and pressure conditions during cold pressing can fully cure the adhesive and fully exert its gluing performance. The modified acrylic resin glue can better fill the pores of the core material under a pressure of 0.6-0.9 MPa and a cold pressing time of 40-80 minutes, forming a firm gluing connection. This synergistic effect can improve the overall quality of the board. Since the adhesive can fully exert its performance, the gluing strength, flatness and other performance indicators of the board are improved, making the final produced formaldehyde-free plywood and formaldehyde-free blockboard substrate of better quality.

[0065] As preferred, the formaldehyde-free plywood and formaldehyde-free blockboard substrate is made, and the specific steps include:

[0066] S31 Prepare materials: formaldehyde-free adhesive; formaldehyde-free plywood and formaldehyde-free blockboard substrate; poplar bleached veneer or high-density fiber board balancing layer;

[0067] The formaldehyde-free adhesive is a modified acrylic resin glue;

[0068] The poplar bleached veneer has a water content of 8-12%, and the high-density fiberboard has a density of 800-950 kg / m³;

[0069] S32 Gluing and compounding: one poplar bleached veneer or high-density fiberboard balancing layer is compounded on the upper and lower surfaces of the formaldehyde-free plywood and formaldehyde-free blockboard substrate, and the formaldehyde-free adhesive is applied at a glue application amount of 140-150 g / m 2 , and the gluing time is controlled within 20-40 minutes;

[0070] S33 Cold pressing: within 40-70 minutes, the pressure is 0.7-0.75 MPa;

[0071] S34 Hot pressing: set the hot pressing temperature to 115-125℃, the time to 5-10 minutes, and the pressure to 0.6-0.9 MPa, and control the moisture content after hot pressing to be 7-8%;

[0072] S35 Sanding: use 240-250 mesh sanding belt to polish, and the internal thickness deviation is within 0.15 mm, the board surface is flat, and the smoothness is Ra 0.7-0.9;

[0073] S36 Edge cutting: secondary edge cutting to obtain the formaldehyde-free plywood and formaldehyde-free blockboard substrate;

[0074] S37 Curing: set the number of days to 8-12 days to obtain the formaldehyde-free plywood and formaldehyde-free blockboard substrate.

[0075] The modified acrylic resin glue is selected as the formaldehyde-free adhesive, which has good bonding performance. It can effectively bond the plywood and blockboard substrate with the balancing layer without formaldehyde. Compared with traditional formaldehyde-containing adhesives, it not only ensures the bonding strength, but also avoids the risk of formaldehyde release, ensuring the environmental protection of the veneered panel. Moreover, the acrylic resin glue itself has good water resistance and weather resistance, so that the veneered panel can still maintain good structural stability in humid environments or large temperature changes.

[0076] For poplar bleached veneer, the water content is controlled within 8-12%, which is a key factor. Suitable water content can ensure that the veneer will not crack due to excessive dryness during subsequent processing, and will not deform due to high water content. After compounding with the substrate, it can better adapt to changes in environmental humidity and reduce deformation caused by changes in moisture.

[0077] The density of high-density fiberboard is between 800-950 kg / m³. Fiberboard with this density range has higher strength and stability. It can provide good support for the substrate, enhance the overall structural performance of the substrate, make the substrate less likely to deform when subjected to external force, and better work with other materials to ensure the flatness and durability of the veneer.

[0078] The amount of formaldehyde-free adhesive applied is between 140-150 g / m². This amount of adhesive can ensure sufficient coverage between the substrate and the balancing layer, ensuring good bonding effect. The application time is controlled within 20-30 minutes. This time range allows the adhesive to fully penetrate the wood fibers, making the bond more secure. Proper adhesive amount and time control can effectively prevent delamination between the balancing layer and the substrate during subsequent processing and use, improving the quality and stability of the substrate.

[0079] On both sides of the formaldehyde-free plywood and formaldehyde-free veneer substrate, a layer of poplar bleached veneer or high-density fiberboard balancing layer is added. This symmetrical composite structure can make the stress distribution of the substrate more uniform in the thickness direction. When the veneer is subjected to external environmental factors such as humidity changes, temperature changes, or external forces, it can better resist deformation and maintain overall flatness, thereby prolonging the service life of the veneer.

[0080] Within 40-70 minutes, apply a pressure of 0.7-0.75 MPa for cold pressing. This cold pressing process can allow the adhesive to initially cure at a lower temperature, making the bond between the substrate and the balancing layer more secure. Proper pressure and time can ensure bonding while avoiding damage to the wood structure due to excessive pressure or time, maintaining the original properties of the wood and providing a good foundation for subsequent hot pressing procedures.

[0081] The hot pressing temperature is set to 115-125°C, the time is 5-10 minutes, and the pressure is 0.6-0.9 MPa. This combination of hot pressing parameters can allow the adhesive to fully cure and further enhance the bonding strength between the substrate and the balancing layer. Within this temperature and pressure range, the moisture in the wood will also be properly adjusted, with a moisture content of 7-8% after hot pressing, allowing the substrate to achieve an ideal moisture balance, which helps to improve the stability and dimensional accuracy of the substrate and reduces deformation caused by moisture changes during subsequent use.

[0082] The 240-250 grit abrasive belt is used for sanding, which can achieve the appropriate roughness and flatness of the substrate surface. The sanding thickness deviation is within 0.15 mm, which can ensure the uniformity of the substrate thickness, which is very important for the subsequent processing and installation of the veneered panel. The panel surface is flat and smooth with a roughness Ra of 0.7-0.9. This high smoothness provides a good surface condition for the subsequent composite or decorative process, and also improves the appearance quality of the substrate, making the veneered panel more beautiful in the final use.

[0083] The formaldehyde-free plywood and formaldehyde-free veneer substrate are obtained by secondary edge cutting, which can accurately control the size of the substrate. This not only meets the diversified demand for the size of the veneered panel in different decoration scenes, but also removes the unevenness, damage and other defects that may occur on the edge of the substrate during the previous processing process, ensuring the edge quality of the substrate and making the veneered panel more convenient and beautiful during installation and splicing.

[0084] The curing time is set to 8-12 days, which can fully release the internal stress of the substrate in the natural environment. After the previous processing process, the substrate may accumulate certain stress, and the curing process can release these stresses, thereby making the performance of the substrate more stable. After curing, the substrate can better adapt to the subsequent processing and use environment, reducing the possibility of deformation, warping and other problems during use.

[0085] As a preferred, the formaldehyde-free substrate hardening treatment, the specific steps include:

[0086] S41 material preparation: the modified hardening primer is a silicone modified saturated polyester resin coating, which is compounded by acrylic coating, silicone, masking agent and curing agent. The ratio of each component is: acrylic coating: silicone: masking agent: curing agent = 100: 1-2: 3-6: 0.2-0.5. The main components include dimethyldiethylsilane, ethylene glycol, terephthalic acid, ion exchanger, silicone, magnesium silicate and polyisocyanate;

[0087] S42 coating treatment: after the formaldehyde-free substrate is cured, the coating operation is carried out. The first coating is 30-40 g / m²;

[0088] S43 polishing treatment: 240 and 320 mesh combined abrasive belt is used for polishing treatment to ensure the surface flatness and smoothness, the roughness Ra is within 0.4-0.6, and the surface hardness reaches 2-4H;

[0089] S44 curing: the curing time is set to 3-5 days;

[0090] S45 coating treatment: the second coating is carried out after the first coating, polishing and curing of the substrate, and the coating amount is 30-40 g / m²;

[0091] S46 polishing treatment: surface polishing is performed again, and polishing treatment is performed using 240-mesh and 320-mesh combined abrasive belts, so as to further improve the surface quality, and the smoothness Ra reaches 0.4-0.5, and the surface hardness reaches 3-4H;

[0092] S47 health preservation: 5-10 days are set, and the hardening treated formaldehyde-free plywood and formaldehyde-free blockboard substrate is obtained.

[0093] Through a series of processes such as coating, polishing and curing of the silicone modified saturated polyester resin coating, the surface hardness of the formaldehyde-free plywood and formaldehyde-free blockboard substrate is improved. From the initial surface hardness of 2-4H, after the second coating and polishing treatment, the surface hardness can reach 3-4H, and the wear resistance and scratch resistance of the board are improved.

[0094] Multiple polishing treatments are performed using 240-mesh and 320-mesh combined abrasive belts, so that the surface smoothness is significantly improved. The smoothness is improved from Ra 0.4-0.6 to Ra 0.4-0.5, and the surface is more flat and smooth. This not only improves the appearance quality of the board, making it more aesthetic, but also facilitates subsequent finishing, such as painting and veneering, so that the subsequent coating or veneer is more flat and firm.

[0095] The modified hardening primer can fill the small pores on the surface of the board to some extent, making the surface more dense. This helps to improve the bonding performance of the board with other materials (such as finishing materials), making the bonding more firm, and also enhances the structural stability of the board itself, reducing the possibility of delamination and cracking during use due to external forces.

[0096] The improvement of surface hardness directly leads to the enhancement of wear resistance and scratch resistance, so that the board can better resist external friction and scratching in daily use, prolonging the service life of the board; good surface smoothness makes the appearance of the board more beautiful, meeting the requirements of modern decoration for material appearance quality, and improving the market competitiveness of the product; it helps to improve the bonding quality of the board with other materials, while enhancing the structural stability of the board itself, ensuring the reliability of the performance of the board during use.

[0097] As preferred, the formaldehyde-free paper with high surface performance is prepared, and the specific steps include:

[0098] S51 preparation of raw materials: 76-82 parts of acrylic emulsion, 15-20 parts of melamine resin, 0.3-0.4 parts of catalyst p-toluenesulfonic acid, 0.12-0.18 parts of wetting agent, 0.1-0.13 parts of penetrating agent, 0.1-0.2 parts of defoaming agent, 3-8.2 parts of deionized water, pre-impregnated paper, and water-based coating is coated;

[0099] The pre-impregnated paper has a tensile strength of 40N / 10m-60N / 20m and a gram weight of 50-80g / m2;

[0100] The coating water-based paint is a water-based acrylate emulsion, a water-based polyurethane or a polyacrylate;

[0101] S52 water-based amino resin preparation:

[0102] S521 according to the proportioning, a certain amount of melamine resin is weighed, deionized water is added, and the melamine resin is diluted to a mass fraction of 50-60%;

[0103] S522 the diluted melamine resin is added to the quantitatively prepared acrylic emulsion, high-speed stirring is carried out at 800-1200 revolutions per minute for 4-5 minutes, and then the speed is reduced;

[0104] S523 then, catalysts, wetting agents, penetrants, defoamers and various corresponding additives are added, and after uniform stirring, a water-based amino resin is obtained and is ready for use;

[0105] S53 roll coating process:

[0106] S531 a specific glue roller is used for roll coating, and the prepared water-based amino resin is injected between the glue rollers;

[0107] S532 the pre-impregnated paper is horizontally unwound by an unwinding machine, and the surface of the paper is coated with the water-based paint after passing through the roll coater, so that a surface coating is obtained;

[0108] S533 drying is carried out by a drying machine, the tensile strength of the pre-impregnated paper is controlled to be 40N / 10m-60N / 20m, and the gram weight is controlled to be 50-80g / m2, so that a formaldehyde-free decorative paper with certain decorative properties and surface properties is obtained, i.e. the high-surface-property formaldehyde-free paper.

[0109] The pre-impregnated paper is an industrial special paper processed by a special process with high-quality wood pulp and titanium dioxide as main raw materials, and is an excellent environment-friendly material with zero formaldehyde, no pollution, easy processing and low energy consumption. The manufacturing process usually involves partial carbonization of raw paper fibers, external coating and internal infiltration treatment of plant-based pre-impregnated raw materials, and coating forming. The pre-impregnated paper has the advantages of strong wear resistance, stable color, high light transmission and shielding capacity, etc.

[0110] The coating water-based paint includes a water-based acrylate emulsion, a water-based polyurethane or a polyacrylate. The water-based acrylate emulsion has good film-forming property, certain weather resistance and chemical corrosion resistance; the water-based polyurethane has large adjustable structure and performance, and has the advantages of green environmental protection, no formaldehyde release, fast drying speed and good film-forming property; and the polyacrylate can be used as a surface coating light oil.

[0111] The water-based acrylic emulsion can form a continuous and uniform film on the coated surface, which is very important for protecting and decorating the coated material. Good film-forming property can make the surface smoother and improve the appearance quality, and also better resist the erosion of the external environment. It also has certain resistance to climate change, including resistance to sunlight, temperature changes, humidity changes, etc. Under different climate conditions, it can maintain good performance and is not prone to discoloration, cracking, peeling, etc., thereby prolonging the service life of the formaldehyde-free decorative panel and making it suitable for a variety of indoor and outdoor environments. It can resist the erosion of some chemicals, making the formaldehyde-free decorative panel coated with water-based acrylic emulsion more durable during cleaning and maintenance and less likely to be damaged by chemicals.

[0112] The water-based polyurethane can be adjusted in performance by changing its molecular structure and composition to meet different application requirements. Its hardness, flexibility, wear resistance, adhesion, etc. can be adjusted to better adapt to different use scenarios and requirements of the formaldehyde-free decorative panel. According to the needs, a water-based polyurethane coating with both high hardness to resist scratches and certain flexibility to adapt to material deformation can be prepared. It meets environmental protection requirements and does not release harmful gases such as formaldehyde during use, which is harmless to indoor air quality and human health. This is particularly important for formaldehyde-free decorative panels, which are used for indoor decoration. It can meet people's demand for healthy and environmentally friendly decoration materials. The water-based polyurethane has fast drying speed and good film-forming property. Fast drying speed can improve production efficiency and reduce production cycle. At the same time, good film-forming property can ensure coating effect, making the surface smooth and uniform, and improving the appearance quality and protection performance of the formaldehyde-free decorative panel.

[0113] As a topcoat gloss oil, polyacrylate can provide a high-gloss surface effect, making the formaldehyde-free decorative panel look brighter and more beautiful, and improving the product's decorative properties. At the same time, it can protect the underlying coating and material to some extent, preventing them from being damaged by the outside world.

[0114] The water-based amino resin is a formaldehyde-free adhesive. In terms of its raw material composition, it mainly includes acrylic emulsion, melamine resin, catalyst p-toluenesulfonic acid, wetting agent, penetrating agent, defoaming agent, deionized water, etc. These raw materials do not contain formaldehyde components, meeting the formaldehyde-free requirements. There is a specific ratio range between each raw material such as acrylic emulsion and melamine resin. This reasonable ratio makes each component work together to achieve good performance. Melamine resin can provide good hardness and wear resistance, while acrylic emulsion can provide flexibility and good bonding performance. P-toluenesulfonic acid is a strong aromatic acid that can provide an acidic environment. During the preparation of water-based amino resin, the addition of p-toluenesulfonic acid can promote the reaction between melamine resin and acrylic emulsion, accelerate the reaction process, and make the reaction more complete and efficient. Through its acidic catalytic action, it can adjust the rate and degree of the reaction, ensure that the water-based amino resin can be prepared according to the expected formula and performance requirements, control the reaction time and the structure and performance of the reaction product, so that the final water-based amino resin has appropriate molecular weight, viscosity and other characteristics to facilitate subsequent roll coating process. In the process of preparing formaldehyde-free paper, the presence of p-toluenesulfonic acid can help improve the performance stability of the product, promote the interaction and crosslinking reaction between the components, and make the surface coating of formaldehyde-free paper have better adhesion, wear resistance, water resistance and other properties, thereby improving the overall quality and service life of the formaldehyde-free veneer.

[0115] In the mixing process, first dilute the melamine resin and then add the acrylic emulsion for high-speed stirring at 800-1200 revolutions per minute for 4-5 minutes, then reduce the speed and add other additives for uniform stirring. High-speed stirring can ensure that the components are fully mixed to form a uniform system and avoid performance differences caused by uneven local components. The fully mixed resin can stably exert its gluing and surface treatment properties during use.

[0116] Compared with commercially available resins, the water-based amino resin prepared by this process does not contain formaldehyde, has better environmental performance, meets the strict requirements of modern formaldehyde-free products, especially in indoor decoration and other application scenarios, and can better protect human health. Due to its reasonable formula design and sufficient mixing process, it has an advantage in gluing performance and can better adapt to the surface characteristics of the substrate and the facing material to provide more uniform gluing strength. When used to prepare formaldehyde-free veneer, the resin can give the veneer certain decorative and surface properties, and can form a good surface coating on the pre-impregnated paper through the roll coating process to improve the surface smoothness and wear resistance. The existing resin does not have the same decorative effect and surface quality as the water-based amino resin in terms of surface treatment performance.

[0117] As a preferred embodiment, the formaldehyde-free veneer composite is prepared by the following steps:

[0118] S61 Dust removal: The substrate is subjected to three dust removal processes of electrostatic, brush and air blowing respectively;

[0119] S62 Gluing and compounding: The gluing glue uses polyvinyl acetate or polyurethane formaldehyde-free fast curing adhesive, the gluing amount is 30-40 g / m 2 , the plate feeding speed is 10-20 meters per minute, the formaldehyde-free paper supporting roller tension is 9-12 N / m, and the paper tension modulation is 10-20 N / 10-20 mm;

[0120] S63 Roller pressing: The roller pressing pressure is set to 0.7-0.9 mm, and the time is 2-10 minutes;

[0121] S64 Edge cutting: The excess edge of the paper is cut off to ensure uniform size;

[0122] S65 Curing: The curing time is set to 24-48 hours to obtain the new formaldehyde-free veneer.

[0123] The substrate is treated by three dust removal processes of electrostatic, brush and air blowing, which can effectively remove dust, wood chips and other impurities on the surface of the substrate. Electrostatic dust removal can adsorb small charged particles, brush dust removal can remove larger impurities, and air blowing dust removal can blow away the dust that is not firmly attached. The three processes cooperate with each other to provide a very clean substrate surface for the subsequent gluing and compounding. A clean surface is conducive to uniform adhesion of glue, avoiding poor adhesion caused by the presence of impurities, thereby improving the compounding quality of the veneer.

[0124] The gluing glue uses polyvinyl acetate or polyurethane formaldehyde-free fast curing adhesive, both of which are formaldehyde-free and meet the environmental protection requirements of veneer. Polyvinyl acetate adhesive has good bonding performance and flexibility, which can adapt to the small deformation of different wood surfaces, making the bonding between the veneer and the substrate more firm and durable. Polyurethane adhesive has high bonding strength, and also has excellent water resistance and weather resistance, which can ensure the stability of the composite structure of the veneer in humid environment or large temperature change.

[0125] The gluing amount is 30-40 g / m², which can ensure good bonding between the veneer and the substrate while avoiding excessive glue overflow, affecting the appearance and quality of the veneer. The plate feeding speed is 10-20 meters per minute, which can allow the glue to have sufficient time for preliminary diffusion and penetration before entering the roller pressing process, while ensuring production efficiency.

[0126] The formaldehyde-free paper supporting roller tension is 9-12 N / m, which can keep the decorative paper flat during the gluing and compounding process, preventing the decorative paper from folding or stretching deformation. The flat decorative paper can better adhere to the base plate, ensuring the surface flatness of the decorative panel and improving the decoration effect and quality of the decorative panel.

[0127] The roller pressure is set to 0.7-0.9 mm for 2-10 minutes, which can make the decorative paper and the base plate closely adhere to each other under the action of the glue. The appropriate pressure can uniformly extrude the glue between the two, expel air, and avoid air bubbles or hollow drum phenomenon. The appropriate roller pressure time can ensure that the glue is fully cured, improve the bonding strength, make the composite structure of the decorative panel more stable, and thus prolong the service life of the decorative panel.

[0128] Cutting off the excess edge of the paper ensures the uniform size, which can make the edges of the decorative panel neat and beautiful. In the decoration process, the size-consistent decorative panel is easier to splice and install, which can improve the construction efficiency and make the final decoration effect more neat and standard, meeting the requirements of modern decoration for precision and aesthetics.

[0129] The curing time is set to 24-48 hours, which can allow the glue to fully cure inside the decorative panel. After the previous roller pressing process, the glue has been preliminarily bonded, but still needs a period of time to reach the best curing state. During the curing period, the molecular structure of the glue will further stabilize, making the bonding between the decorative paper and the base plate more firm, improving the overall strength and stability of the decorative panel, and ensuring that the decorative panel will not have quality problems such as decorative paper falling off during long-term use.

[0130] In summary, the present application has the following advantages:

[0131] 1. Compared with the prior art, the formaldehyde-free decorative panel and its preparation method provided by the present application are safe and environmentally friendly. From the base plate to the decorative paper, formaldehyde is not used, avoiding the pollution of indoor environment caused by formaldehyde release, protecting the health of residents, and the base plate is prepared by using formaldehyde-free adhesive modified acrylic resin glue, which eliminates formaldehyde from the source. The decorative paper is a modified pre-impregnated paper, also without formaldehyde. In the entire preparation process, formaldehyde-free materials and environmentally friendly processes are selected, and the preparation and use of formaldehyde-free adhesive avoid the problem of formaldehyde release of traditional adhesives. High-surface-performance formaldehyde-free paper is prepared by using formaldehyde-free raw materials such as water-based amino resin, which meets the environmental protection requirements.

[0132] 2. Compared to existing impregnated paper-faced engineered wood panels and pre-impregnated paper-faced engineered wood panels, the formaldehyde-free decorative panel of this invention has higher strength and stability. Using formaldehyde-free plywood and formaldehyde-free blockboard as the base material, through reasonable combination and processing, and a specific pressing process, the structural advantages of plywood and blockboard complement each other, enhancing resistance to deformation. The base material structure is reasonable, with its internal multi-layer structure and core-veneer structure working together to provide a solid foundation for the decorative panel, capable of withstanding daily impacts, compression, and other external forces without easily being damaged. The balancing layer uses formaldehyde-free bleached poplar veneer or high-density fiberboard, improving the overall structural performance of the base material, making it more robust and durable, and stronger in resisting deformation and external damage. The improved pre-impregnated paper undergoes special treatment and has a certain tear resistance. The formaldehyde-free decorative panel prepared by this invention has richer colors and textures. This invention offers a variety of textures and finishes, including floral, skin-like, zero-degree, and high-gloss options, which changes the traditional flat, matte surface of pre-impregnated paper decorative panels. This expands the application scenarios and fields, providing a variety of decorative effects to meet the needs of different decoration styles and offering rich choices for interior decoration. During the substrate and decorative panel composite manufacturing process, multiple trimming operations, including secondary trimming and removing excess paper edges, precisely control the dimensions, ensuring consistent panel size and neat, aesthetically pleasing edges. This meets the size requirements of different decoration scenarios and makes installation and splicing of the decorative panels more convenient, improving construction efficiency and ensuring a neat and standardized final decorative effect. The formaldehyde-free decorative panel prepared by this invention uses a flat-laying process, which is highly efficient and low-consumption. Its production efficiency is higher than that of impregnated paper-faced engineered wood panels, and its production energy consumption is far lower than that of existing decorative panels, making it highly efficient and low-consumption.

[0133] 3. The production process of this invention is advanced and efficient. From the preparation of formaldehyde-free adhesives and the separate preparation of substrates and formaldehyde-free paper to the final composite manufacturing, each step has been carefully designed and optimized. The links between each link are interconnected, ensuring the smooth operation of the entire production process and improving production efficiency and product quality. In each process flow, parameters such as temperature, pressure, time, and adhesive application amount are strictly controlled and optimized. The control of reaction temperature, stirring speed, and time in the preparation of formaldehyde-free adhesives ensures excellent adhesive performance. The setting of adhesive application amount, cold pressing, and hot pressing parameters in the substrate manufacturing process ensures the bonding quality and performance stability of the substrate. The surface hardening pretreatment technology of the substrate is applied to paper decorative panels for the first time, which greatly improves the surface effect, significantly increases surface hardness, significantly reduces surface abrasion resistance compared to traditional decorative panels, and improves surface scratch resistance. The control of parameters such as adhesive application amount, rolling pressure, and time in the composite manufacturing of decorative panels improves the composite quality and production efficiency.

[0134] 4、The adhesive technical innovation in the veneer panel preparation method of the application adopts new type formaldehyde-free adhesive such as modified acrylic resin glue, which has good bonding performance, flexibility, water resistance and weather resistance; the formula design is reasonable, specific fillers and humidity adjusting materials are added, and the reaction is carried out under nitrogen protection, so that the components are fully mixed, the adhesive performance is better than that of common formaldehyde-free adhesives on the market, and the surface properties of the substrate and the veneer material are better adapted, a more uniform bonding strength is provided, and the cost is reduced;

[0135] 5、The high molecular surface treatment technology is applied in the veneer panel preparation method of the application, and in the formaldehyde-free substrate hardening treatment and the preparation of formaldehyde-free paper with high surface performance, silicone modified saturated polyester resin paint, water-based amino resin and other high molecular materials and related technologies are applied; through the hardening treatment of the substrate, the surface hardness and smoothness are improved, and the wear resistance and scratch resistance are enhanced; the water-based amino resin plays an important role in the preparation of formaldehyde-free paper, and endows the formaldehyde-free paper with good decorative and surface performance, so that the formaldehyde-free paper has better bonding performance and surface quality;

[0136] 6、In the whole preparation process, low temperature and low pressure process is adopted in the hot pressing process of the preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate, the use of low temperature bonding and low energy consumption production technology reduces the energy consumption, has great energy saving effect, and meets the requirements of sustainable development; at the same time, the low temperature process also reduces the influence on the performance of the material, and ensures the product quality;

[0137] 7、The formaldehyde-free veneer panel composite production adopts advanced methods such as flat paste process, which can quickly and accurately paste the formaldehyde-free substrate and formaldehyde-free paper with high surface performance together; reasonable feeding speed and glue coating amount control in the glue coating composite process, and suitable pressure and time setting in the rolling process, can not only ensure the product quality, but also improve the production efficiency, help to reduce the production cost, make the formaldehyde-free veneer panel more competitive in the market, and meet the growing demand of the market for environment-friendly decorative materials;

[0138] 8、The whole preparation process is reasonably designed, the operation of each process is standardized, and large-scale production can be easily realized; through precise parameter control and application of advanced equipment and technology, the stability and consistency of product quality in large-scale production process can be ensured, the production efficiency is improved, the production cost is reduced, and sufficient formaldehyde-free veneer panel products are provided for the market. DETAILED DESCRIPTION

[0139] The specific embodiments are only an explanation of the application, and are not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the patent law.

[0140] Example 1

[0141] S1 Preparation of formaldehyde-free adhesive: 20 parts of acrylic monomer, 50 parts of acrylic ester monomer and 60 parts of deionized water are mixed, then 10 parts of hydroxyl functional group, 6 parts of polyvinyl alcohol, 2 parts of emulsifier and 0.02 parts of initiator are added, and the reaction is carried out at 60°C under nitrogen protection with stirring speed of 500 rpm for 4 hours to prepare modified acrylic resin emulsion; the prepared modified acrylic resin emulsion is used as the main body, a part of flour is added as filler, and a certain amount of humidity adjusting material calcium chloride or magnesium chloride is added, and the formaldehyde-free adhesive is prepared by high speed stirring for 12 minutes; modified acrylic resin emulsion: flour: humidity adjusting material = 100:20:1;

[0142] S2 Preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate: the raw material ratio is: Chinese fir core: eucalyptus short core = 5:4, the formaldehyde-free adhesive coating amount is 170 g / m², the assembly is designed according to the design scheme, and the coating time is controlled within 50 minutes; the cold pressing time is set to 60 minutes, and the pressure is 0.85 MPa; the overlap is cut off, and the core gap is filled; the temperature is 125°C, the time is 30 minutes, the pressure is 0.75 MPa, and the hot pressing is carried out to the core board with water content of 9%, and the water content deviation is 1.6%; the core board is hot pressed within 12 hours after cold pressing; the 60 and 120 mesh combined abrasive belt is selected, and the sanding is carried out to the specified thickness of 15.8 mm, the thickness deviation of the board is within 0.2 mm, and the board surface smoothness is Ra1.6; the board surface core gap is scraped and filled; the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained by one-time edge cutting, and the specification is 1240*2460 mm; the curing period is 8 days, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained;

[0143] S3 Preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate: one 1.0 mm high-density fiber board balancing layer is compounded on the upper and lower surfaces of the 15.8 mm formaldehyde-free blockboard substrate, the formaldehyde-free adhesive coating amount is 150 g / m 2 , the coating time is controlled within 40 minutes; the cold pressing is carried out within 40 minutes, and the pressure is 0.75 MPa; the hot pressing temperature is set to 120°C, the time is 10 minutes, the pressure is 0.7 MPa, and the water content after hot pressing is controlled to be 8%; the 240 mesh abrasive belt is used for polishing, the sanding is carried out to the thickness deviation of the board within 0.15 mm, the board surface is flat, and the smoothness is Ra0.8; the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained by two-time edge cutting, and the specification after edge cutting is 1220*2440 mm; the curing period is set to 10 days, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained;

[0144] S4 Formaldehyde-free substrate hardening treatment: the components and proportions of the modified hardening primer are as follows: acrylic paint: silicone: masking agent: curing agent = 100:2:6:0.5; after the formaldehyde-free substrate is incubated, the coating operation is performed, the first coating is performed, and the coating amount is 40 g / m2; polishing treatment is performed using a combination of 240 mesh and 320 mesh abrasive belts to ensure a smooth and clean surface; the incubation and curing time is set to 5 days; the second coating is performed after the first coating, polishing, and incubation and curing of the substrate, and the coating amount is 40 g / m2; surface polishing is performed again using a combination of 240 mesh and 320 mesh abrasive belts to further improve the surface quality; the incubation period is set to 10 days, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate after hardening treatment is obtained;

[0145] S5 Preparation of formaldehyde-free paper with high surface performance: 20 parts of melamine resin are weighed according to the proportion, 8.2 parts of deionized water are added, and the melamine resin is diluted to 60% by mass fraction; the diluted melamine resin is added to 82 parts of acrylic emulsion, and high-speed stirring is performed at 1200 rpm for 5 minutes, and then the speed is reduced; then 0.4 parts of p-toluene sulfonic acid catalyst, 0.18 parts of wetting agent, 0.13 parts of penetrating agent, and 0.2 parts of defoaming agent are added, and the mixture is stirred uniformly to obtain a water-based amino resin, which is ready for use; a special glue roller is used for roller coating, and the prepared water-based amino resin is injected between the glue rollers; the pre-impregnated paper is horizontally unwound by a unwinding machine, and the surface is coated with water-based paint after passing through the roller coater to obtain a surface coating; drying is performed by a drying machine, the tensile strength of the pre-impregnated paper is controlled to be 60 N / 10 m, and the grammage is controlled to be 80 g / m2, and a formaldehyde-free decorative paper with certain decorative and surface performance, i.e., the formaldehyde-free paper with high surface performance, is obtained.

[0146] S6 Composite production of formaldehyde-free decorative panel: the substrate is subjected to three dust removal processes of electrostatic, brush and air blowing; the glue used for coating is polyurethane formaldehyde-free fast curing adhesive, the coating amount is 35 g / m 2 , the feeding speed is 20 meters per minute, the tension of the formaldehyde-free paper support roller is 12 N / m, and the paper tension modulation is 20 N / 10 mm; the roller pressure is set to 0.8 mm, and the time is set to 2 minutes; the excess edge of the paper is cut off to ensure uniform size; the incubation and curing time is set to 48 hours, and the new formaldehyde-free decorative panel is obtained.

[0147] Example 2

[0148] S1 Preparation of formaldehyde-free adhesive: 20 parts of acrylic monomer, 50 parts of acrylic ester monomer and 60 parts of deionized water are mixed, then 10 parts of hydroxyl functional group, 6 parts of polyvinyl alcohol, 2 parts of emulsifier and 0.02 parts of initiator are added, and the reaction is carried out at 60°C under nitrogen protection for 4 hours with stirring speed of 500 rpm; the modified acrylic resin emulsion is prepared; a part of flour is added as filler, and a certain amount of humidity adjusting material calcium chloride or magnesium chloride is added as auxiliary, and the formaldehyde-free adhesive is prepared by mixing at high speed of 500 rpm for 15 minutes; modified acrylic resin emulsion: flour: humidity adjusting material = 100:22:1;

[0149] S2 Preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate: the raw materials are mixed in a ratio of eucalyptus short core: eucalyptus long core = 5:4, the formaldehyde-free adhesive is applied at a glue application amount of 160 g / m², and the assembly is designed according to the design scheme; the glue application time is controlled within 50 minutes; the cold pressing time is set to 60 minutes, and the pressure is 0.85 MPa; the overlapping part is cut off, and the core gap is filled; the temperature is 125°C, the time is 30 minutes, the pressure is 0.8 MPa, and the hot pressing is carried out to the core board with water content of 9%, and the water content deviation is 1.7%; the core board is hot pressed within 12 hours after cold pressing; the 60 and 120 mesh combined abrasive belt is selected, and the sanding is carried out to the specified thickness of 15.8 mm, the thickness deviation of the board is within 0.2 mm, and the board surface smoothness is Ra1.6; the board surface core gap is scraped and filled; the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained by one-time edge cutting, and the size is 1240*2460 mm; the curing period is 7 days, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained;

[0150] S3 Preparation of formaldehyde-free plywood and formaldehyde-free blockboard substrate: one 1.0 mm high-density fiberboard balancing layer is compounded on the upper and lower surfaces of the 15.8 mm formaldehyde-free plywood substrate, the formaldehyde-free adhesive is applied at a glue application amount of 150 g / m 2 , and the glue application time is controlled within 40 minutes; other operations are the same as those in step S3 of example 1, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate are obtained;

[0151] Steps S4, S5 and S6 are the same as those in example 1, and the new formaldehyde-free veneer is obtained.

[0152] Example 3

[0153] Steps S1, S2 and S3 are the same as those in example 1;

[0154] S4 Formaldehyde-free substrate hardening treatment: the components and proportions of the modified hardening primer are as follows: acrylic paint: silicone: masking agent: curing agent = 80: 1: 3: 0.2; after the formaldehyde-free substrate is incubated, the coating operation is carried out, the first coating is carried out, and the coating amount is 30 g / m2; polishing treatment is carried out using a combination of 240 mesh and 320 mesh abrasive belts to ensure a smooth and clean surface with a smoothness Ra of 0.4; after the first coating, polishing and incubation and curing of the substrate, the second coating is carried out, and the coating amount is 30 g / m2; surface polishing is carried out again using a combination of 240 mesh and 320 mesh abrasive belts to further improve the surface quality, and the smoothness Ra reaches 0.4; the incubation time is set to 5 days, and the formaldehyde-free plywood and formaldehyde-free blockboard substrate after hardening treatment is obtained;

[0155] S5 Preparation of formaldehyde-free paper with high surface performance: 15 parts of melamine resin are weighed according to the proportion, 3 parts of deionized water are added, and the melamine resin is diluted to 50% by mass fraction; the diluted melamine resin is added to 76 parts of acrylic emulsion, and stirred at a high speed of 800 revolutions per minute for 4 minutes, and then the speed is reduced; then 0.3 parts of p-toluene sulfonic acid catalyst, 0.12 parts of wetting agent, 0.1 parts of penetrating agent, and 0.1 parts of defoaming agent are added, and the mixture is stirred uniformly to obtain a water-based amino resin, which is ready for use; a special glue roller is used for roller coating, and the prepared water-based amino resin is injected between the glue rollers; the pre-impregnated paper is horizontally unwound by a unwinding machine, and the surface is coated with water-based paint after passing through the roller coater to obtain a surface coating; drying is carried out by a drying machine, the tensile strength of the pre-impregnated paper is controlled to be 40 N / 10 m, and the grammage is controlled to be 50 g / m2, and a formaldehyde-free decorative paper with certain decorative and surface performance, i.e. formaldehyde-free paper with high surface performance, is obtained.

[0156] S6 Composite production of formaldehyde-free decorative panel: the substrate is subjected to three dust removal processes of electrostatic, brush and air blowing; the glue used for coating is polyurethane formaldehyde-free fast curing adhesive, the coating amount is 35 g / m 2 , the feeding speed is 10 meters per minute, the tension of the formaldehyde-free paper supporting roller is 9 N / m, and the paper tension modulation is 10 N / 20 mm; the roller pressure is set to 0.8 mm, and the time is set to 10 minutes; the excess edge of the paper is cut off to ensure uniform size; the incubation and curing time is set to 24 hours, and the new formaldehyde-free decorative panel is obtained.

[0157] Example 4

[0158] S1 Preparation of formaldehyde-free adhesive: First, mix 25 parts of acrylic monomer, 60 parts of acrylic ester monomer and 90 parts of deionized water, then add 16 parts of hydroxyl functional group, 10 parts of polyvinyl alcohol, 4 parts of emulsifier and 0.6 parts of initiator, and react at 80°C under nitrogen protection for 6 hours with stirring at 800 rpm. A modified acrylic resin emulsion is prepared. The modified acrylic resin emulsion is used as the main body, and a part of flour is added as the filler, supplemented with a certain amount of moisture adjusting material calcium chloride or magnesium chloride, and mixed by high speed stirring at 3000 rpm for 15 minutes to obtain the formaldehyde-free adhesive. Modified acrylic resin emulsion: flour: moisture adjusting material = 100:25:1.

[0159] The remaining steps are the same as in Example 1 to obtain the new formaldehyde-free veneer.

[0160] Example 5

[0161] S1 Preparation of formaldehyde-free adhesive: First, mix 25 parts of acrylic monomer, 60 parts of acrylic ester monomer and 90 parts of deionized water, then add 16 parts of hydroxyl functional group, 10 parts of polyvinyl alcohol, 4 parts of emulsifier and 0.6 parts of initiator, and react at 80°C under nitrogen protection for 6 hours with stirring at 800 rpm. A modified acrylic resin emulsion is prepared. The modified acrylic resin emulsion is used as the main body, and a part of flour is added as the filler, supplemented with a certain amount of moisture adjusting material calcium chloride or magnesium chloride, and mixed by high speed stirring at 3000 rpm for 15 minutes to obtain the formaldehyde-free adhesive. Modified acrylic resin emulsion: flour: moisture adjusting material = 100:25:1.

[0162] The remaining steps are the same as in Example 1 to obtain the new formaldehyde-free veneer.

[0163] Comparative Example 1

[0164] A traditional veneer is obtained by flatly pasting ordinary pre-impregnated paper on an ENF grade ecological board.

[0165] 1. Experimental method

[0166] A series of performance tests are conducted on the veneers prepared in Examples 1-5 and Comparative Example 1, including formaldehyde release, bonding strength, surface bonding strength, surface wear resistance, surface hardness and other indicators.

[0167] 1.1 Formaldehyde release

[0168] The detection is carried out according to GB / T 39600-2021 "Formaldehyde Emission of Wood-based Panels and Their Products" and T / CNFPIA 1003-2022 related standards for detection and judgment. These two standards set clear classification requirements and detection specifications for formaldehyde emission of wood-based panels and their products from different angles, ensuring the scientificity and accuracy of the test results, and fully reflecting the formaldehyde emission of the product in different use environments.

[0169] The detection is carried out under specific temperature conditions, and two temperature nodes of 23°C and 30°C are set respectively. The prepared sample plates of the embodiment of the application and the sample plates of the control group (ordinary pre-impregnated paper is pasted on the ENF level ecological board) are placed in an environment chamber meeting the standard requirements, and the temperature, humidity, air flow rate and other conditions in the environment chamber are strictly controlled according to the standard. Within the specified time interval, the formaldehyde concentration in the air in the environment chamber is continuously monitored and data is collected by using professional formaldehyde detection instruments, such as using mature detection technologies such as spectrophotometry or gas chromatography. After a certain period of stabilization, according to the collected data, the formaldehyde emission of the sample plate at different temperatures is accurately calculated according to the calculation formula in the corresponding standard.

[0170] 1.2 Glue strength

[0171] The detection is carried out according to GB / T 34722-2017 “Impregnated paper laminated wood floor” standard. The standard formulates detailed technical requirements and detection specifications for the glue strength of wood floor and similar products. Although the product of the application may not be a wood floor, the detection method and judgment criterion for glue strength are universal and can objectively evaluate the firmness of the glue connection between the layers of the product.

[0172] Detection method: first, a test piece of a specified size and shape is cut from the prepared sample plate, ensuring that the test piece is representative and meets the size specifications required by the standard. Then, the test piece is fixed on a professional glue strength testing equipment, and by applying an increasing pulling force to the test piece, the external force that may be encountered in actual use is simulated until the glue joint of the test piece is damaged. During the test, the equipment records the size of the pulling force and the state of the test piece when the glue joint is damaged. Finally, according to the calculation formula specified in GB / T 34722-2017 standard, the glue strength value of the sample plate is accurately calculated according to the data collected during the test.

[0173] 1.3 Surface glue strength

[0174] The detection is also based on GB / T 34722-2017 “Impregnated paper laminated wood floor” standard. The standard also has clear provisions for the detection of surface glue strength, and through unified standard specifications, the performance differences of different sample plates in surface gluing can be compared fairly and accurately.

[0175] Similar to the glue strength test, specific test pieces conforming to the standard size requirements are first prepared from the sample board. The test pieces are placed on a device specially used for surface glue strength testing, which usually uses a specific clamp and loading device to accurately apply a pulling force perpendicular to the surface of the glue part of the test piece. During the test, the pulling force is gradually increased until the surface glue layer of the test piece is damaged, and the device continuously records the pulling force value and the related conditions at the time of damage. Finally, according to the calculation method specified in GB / T 34722-2017 standard, the surface glue strength index of the sample board is calculated based on the test data.

[0176] 1.4 Surface wear resistance

[0177] The test is conducted in accordance with GB / T 34722-2017 "Laminated Wood Flooring with Impregnated Paper". This standard sets detailed evaluation indicators and testing procedures for the surface wear resistance of products such as wood flooring, which can be used for comparative testing of the surface wear resistance of the sample board and the control group sample board.

[0178] Select a certain area of the sample board surface as the test area, and fix the sample board on a professional surface wear resistance testing equipment, such as a Taber abrasion tester, etc. Install the specified type of grinding wheel on the testing equipment, and perform the test according to the standard parameters such as load, speed and friction times. After the grinding wheel continuously rubs the surface of the sample board for a certain number of times, the depth of wear, weight loss or appearance change of the sample board surface are measured, and the surface wear resistance of the sample board is quantitatively evaluated according to the judgment rules in GB / T 34722-2017 standard, to determine the surface wear resistance grade or specific wear resistance value.

[0179] 1.5 Surface hardness

[0180] The test is performed in accordance with GB / T 37005-2018 "Wood Flooring Surface Hardness Test Method". This standard specifically formulates a scientific and reasonable testing method and evaluation system for the surface hardness testing of wood flooring, which also has reference value and applicability for the surface hardness testing of the decorative panel and other products involved in the invention.

[0181] First, select appropriate test points on the surface of the sample board to ensure uniform and representative distribution of the test points. Then, use a professional surface hardness testing instrument, and vertically press the indenter of the Shore D hardness tester on the test points, and perform the operation according to the standard specified pressure application method and holding time. The hardness tester will automatically read and record the depth of the indenter pressed into the surface of the sample board or the rebound force and other related data, and according to the calculation formula and judgment criteria in GB / T 37005-2018 standard, the surface hardness value of the sample board is calculated based on these test data, so as to accurately evaluate the surface hardness performance of the sample board.

[0182] 2. Experimental results

[0183] The detection results of formaldehyde emission, bonding strength, surface bonding strength, surface wear resistance, surface hardness, and other indicators of the veneered panels prepared in Examples 1-5 and Comparative Example 1 are shown in the following table.

[0184] Table 1 Comparison of performance detection of veneered panels prepared in each group

[0185]

[0186] 2.1 Formaldehyde emission analysis

[0187] As can be seen from the table, at both 23℃ and 30℃, the formaldehyde emission of Examples 1-5 is significantly lower than that of Comparative Example 1. At the lower temperature of 23℃, the formaldehyde emission of Examples 1-5 is between 0.006-0.008 mg / m³, while the formaldehyde emission of Comparative Example 1 is 0.021 mg / m³; at 30℃, the formaldehyde emission of Examples increases slightly, but still remains at a low level of 0.012-0.018 mg / m³, while Comparative Example 1 increases significantly to 0.132 mg / m³. This indicates that the veneered panels of the examples can better control formaldehyde emission at different temperature environments, especially when the temperature rises, and have more stable low formaldehyde emission performance.

[0188] From the data of formaldehyde emission, Examples 1-5 exhibit extremely low formaldehyde emission levels at detection temperatures of 23℃ and 30℃. Compared with Comparative Example 1, the formaldehyde emission of Examples is significantly reduced. This means that the veneered panels prepared by the present application have significant advantages in environmental performance, can meet more stringent environmental standards, and especially in indoor environments, whether at room temperature or at slightly higher temperatures, can effectively reduce the potential harm of formaldehyde to human health.

[0189] It is worth noting that as the temperature rises from 23℃ to 30℃, the formaldehyde emission of Examples increases slightly, but the increase is small and still at a low level. This indicates that the veneered panels of the present application have relatively stable formaldehyde emission at different temperature environments, and will not release a large amount of formaldehyde due to temperature changes, further demonstrating the reliability of their environmental performance.

[0190] 2.2 Wear value analysis

[0191] The abrasion value is a key indicator of the surface wear resistance of the veneer. The abrasion values of Examples 1-5 are much lower than that of Comparative Example 1, which indicates that the veneer prepared by the present application has excellent wear resistance. Lower abrasion values help the veneer maintain its decorative effect and functional integrity during long-term use. The abrasion values of Examples 1-5 are between 40-43 mg / 100r, while the abrasion value of Comparative Example 1 is higher, reaching 132 mg / 100r, indicating that its surface is more prone to wear and tear, and may quickly develop scratches, discoloration, and other issues, affecting its appearance and performance. This shows that the surface wear resistance of the veneer of the examples is significantly better than that of the comparative example, and after the same friction test, the degree of wear on the surface of the example veneer is much smaller, better maintaining the surface integrity and aesthetics.

[0192] The abrasion values of the examples are relatively stable with a small fluctuation range, which reflects the consistency of the examples in terms of wear resistance, indicating that the preparation method of the formaldehyde-free veneer of the present application effectively controls and guarantees the surface wear resistance of the veneer due to the use of a relatively stable preparation process and material formula.

[0193] 2.3 Surface hardness analysis

[0194] From the surface hardness data, the surface hardness values of Examples 1-5 are significantly higher than that of Comparative Example 1. The surface hardness of the examples ranges from 80-88, while that of Comparative Example 1 is only 50. This significant difference indicates that the veneer prepared by the present application has a significant improvement in surface hardness. Higher surface hardness helps to improve the durability of the veneer. In contrast, the lower surface hardness of Comparative Example 1 makes it more prone to surface defects such as scratches and dents, which may further expand over time, affecting the service life of the veneer. The veneer of the present application, due to its high surface hardness, can maintain a good surface state for a longer period of time, reducing the frequency of maintenance and replacement, which is of great significance to improving the economy and practicality of the product. This shows that the veneer prepared by the present application has significant advantages in terms of surface hardness, and can better resist external pressure, friction and scratching, thereby more effectively maintaining the integrity and aesthetics of the surface in daily use.

[0195] The surface hardness of the examples as a whole remains in a relatively high and concentrated range. This indicates that the preparation process of the present application has a certain stability in controlling the surface hardness. This stability can be achieved through optimization of raw material selection and quality control, as well as precise setting of production process parameters, to ensure the consistency and reliability of product quality.

[0196] 2.4 Analysis of glueing strength and surface glueing strength

[0197] From the test results, the average glue strength and the average surface glue strength of Examples 1-5 are generally higher than those of Comparative Example 1. The average glue strength of the Examples is between 1.12-1.21, and the average surface glue strength is between 1.02-1.08, while the glue strength of Comparative Example 1 is 0.72, and the surface glue strength is 0.61. This indicates that the Examples perform better in terms of gluing, with a higher degree of firmness between the layers, better resistance to delamination, peeling, and other issues that may arise during use, thereby ensuring the overall quality and service life of the decorative panel. The glue strength and surface glue strength between Examples are also relatively stable, which shows that the preparation process of the Examples can ensure a consistent quality level in the gluing link, which is conducive to batch production and quality control of the product.

[0198] Higher glue strength and surface glue strength help to ensure the structural integrity of the decorative panel. In daily use, the decorative panel can better withstand external forces such as impact and pressure, reducing the occurrence of quality problems such as delamination and peeling, thereby prolonging the service life of the decorative panel and improving the reliability and practicality of the product.

[0199] Experiments show that compared with the comparative example, the decorative panel of the example performs better in terms of formaldehyde emission, glue strength, surface glue strength, surface wear resistance and surface hardness. The present application combines multiple technologies to provide a formaldehyde-free, high-surface performance and low-carbon emission decorative panel preparation method. The decorative panel is composed of formaldehyde-free substrate and formaldehyde-free decorative paper, through detailed process steps and precise process parameter control, excellent performance is achieved, which has significant advantages in environmental protection, production efficiency, surface performance, etc.

Claims

1. A formaldehyde-free decorative panel, characterized in that, Specifically, it includes: A formaldehyde-free substrate and a formaldehyde-free decorative paper laminated to the surface of the formaldehyde-free substrate by a flat lamination process; The formaldehyde-free substrate includes formaldehyde-free plywood and formaldehyde-free blockboard, specifically including: a substrate layer, a balancing layer and a hardening base coating layer located between the substrate layer and the balancing layer. The substrate layer is made of one or two types of formaldehyde-free plywood cores or eucalyptus cores using formaldehyde-free adhesives through processes such as gluing, assembly, cold pressing, core trimming, hot pressing, thickness sanding, edge trimming, and polishing; the moisture content of the plywood core is 5-8%, and the moisture content of the eucalyptus core is 6-12%. The balancing layer is a formaldehyde-free bleached poplar veneer or high-density fiberboard. The hardening base coating is formed by an organosilicon-modified saturated polyester resin coating, wherein the weight ratio of acrylic coating, organosilicon, masking agent and curing agent in the organosilicon-modified saturated polyester resin coating is 100:(1-2):(3-6):(0.2-0.5); after sanding, the surface finish of the hardening base coating is Ra0.3-0.5 and the surface hardness is 3-5H. The formaldehyde-free decorative paper is a pre-impregnated paper with a surface coating composed of an aqueous amino resin. The aqueous amino resin comprises 76-82 parts by weight of acrylic emulsion, 15-20 parts by weight of melamine resin, and 0.3-0.4 parts by weight of the catalyst p-benzenesulfonic acid. The preparation method of the formaldehyde-free decorative panel includes the following specific process flow: Preparation of S1 formaldehyde-free adhesive; Preparation of S2 formaldehyde-free plywood and formaldehyde-free blockboard substrates; S3 formaldehyde-free plywood and formaldehyde-free blockboard substrate manufacturing; S4 formaldehyde-free substrate hardening treatment; Preparation of S5 high surface performance formaldehyde-free paper; S6 formaldehyde-free decorative panel composite manufacturing; The formaldehyde-free adhesive is a modified acrylic resin adhesive, and the preparation of the formaldehyde-free adhesive is the preparation of the modified acrylic resin, specifically including the following steps: S11 Raw material preparation: 20-25 parts acrylic monomer, 50-60 parts acrylate monomer, 10-16 parts hydroxyl functional group, 5-10 parts polyvinyl alcohol, 2-4 parts emulsifier, 0.02-0.06 parts initiator, 60-90 parts deionized water; The acrylic monomer is one or a mixture of two of acrylic acid, methyl acrylate or ethyl acrylate; The acrylate monomer is obtained by transesterification of methyl acrylate and isopentyl glycol. Preparation of S12 modified acrylic resin emulsion: First, mix acrylic monomers, acrylate monomers and deionized water, then add hydroxyl functional group, polyvinyl alcohol, emulsifier and initiator, and react continuously at 40-80℃ and 300-800 rpm for 2-6 hours under nitrogen protection to obtain modified acrylic resin emulsion. Preparation of S13 formaldehyde-free adhesive: The modified acrylic resin emulsion is used as the main component, with some flour added as filler and a certain amount of moisture-conditioning material calcium chloride or magnesium chloride added. The mixture is stirred at high speed of 500-3000 rpm for 10-15 minutes to obtain the modified acrylic resin adhesive, which is a formaldehyde-free adhesive. The ratio of modified acrylic resin emulsion: flour: moisture-conditioning material is 80-100: 20-25: 0.5-1.

2. The formaldehyde-free decorative panel according to claim 1, characterized in that, The specific steps for preparing the formaldehyde-free plywood and formaldehyde-free blockboard substrates include: S21 Materials needed: Formaldehyde-free adhesive and core material; The core material is one or both of formaldehyde-free plywood core and eucalyptus core; the moisture content of the plywood core is 5-8%, and the moisture content of the eucalyptus core is 6-12%. S22 Adhesive Assembly: Assemble the core material into a cross-shaped pattern according to the design scheme. Apply 160-170g / m² of formaldehyde-free adhesive and control the application time to 40-60 minutes. S23 Cold Press: Set the cold pressing time to 40-80 minutes and the pressure to 0.6-0.9 MPa; S24 Core Repair: Cut off overlaps and fill gaps in the core; S25 hot pressing: temperature is 120-130℃, time is 20-60 minutes, pressure is 0.6-0.9MPa, hot pressing until the billet moisture content is 7-9%, with a moisture content deviation of 1-2%; after cold pressing, the billet must be hot pressed within 12 hours. S26 Fixed Thickness Sanding: Select a combination of 60 and 120 mesh sanding belts, sand to the specified thickness of 15-16mm, with the thickness deviation within the board within 0.2mm, and the surface finish Ra 1.5-1.7; S27 Scraping: Filling in areas where the core is missing on a flat surface; S28 Edge Trimming: Obtain formaldehyde-free plywood and formaldehyde-free blockboard substrates in one edge trimming step, with a trimming amount of 20-30mm; S29 conditioning: The conditioning cycle is 5-8 days, resulting in the formaldehyde-free plywood and formaldehyde-free blockboard substrates.

3. The formaldehyde-free decorative panel according to claim 2, characterized in that, The specific steps for manufacturing the formaldehyde-free plywood and formaldehyde-free blockboard substrates include: S31 Materials needed: Formaldehyde-free adhesive; Formaldehyde-free plywood and formaldehyde-free blockboard substrate; Poplar bleached veneer or high-density fiberboard balancing layer; The bleached poplar veneer has a moisture content of 8-12%, and the high-density fiberboard has a density of 800-950 kg / m³. S32 adhesive lamination: A layer of bleached poplar veneer or high-density fiberboard is laminated on both the top and bottom of a formaldehyde-free plywood and a formaldehyde-free blockboard substrate. The formaldehyde-free adhesive application rate is 140-150g / m². 2 The glue application time should be controlled between 20 and 40 minutes; S33 cold pressing: 0.7-0.75MPa within 40-70 minutes; S34 Hot Pressing: Set the hot pressing temperature to 115-125℃, time to 5-10 minutes, pressure to 0.6-0.9MPa, and control the moisture content after hot pressing to 7-8%. S35 Sanding: Polished with 240-250 grit sandpaper, sanding until the thickness deviation within the board is within 0.15mm, the board surface is flat, and the smoothness Ra0.7-0.9; S36 trimming: Secondary trimming yields formaldehyde-free plywood and formaldehyde-free blockboard substrates; S37 conditioning: Set the number of days to 8-12 days to obtain the formaldehyde-free plywood and formaldehyde-free blockboard substrate.

4. The formaldehyde-free decorative panel according to claim 3, characterized in that, The hardening treatment of the formaldehyde-free substrate includes the following specific steps: S41 Material Preparation: The modified hardening primer is a silicone-modified saturated polyester resin coating, which is formulated with acrylic paint, silicone, masking agent, and curing agent. The ratio of each component is: acrylic paint: silicone: masking agent: curing agent = 100:1-2:3-6:0.2-0.5; its main components include dimethyl diethylsilane, ethylene glycol, terephthalic acid, ion exchanger, silicone, magnesium silicate, and polyisocyanate. S42 Coating Treatment: Coating is performed after the formaldehyde-free substrate has been cured. The first coating is 30-40 g / m². S43 Polishing Treatment: Polishing is performed using a combination of 240-mesh and 320-mesh abrasive belts to ensure a smooth and clean surface with a smoothness Ra of 0.4-0.6 and a surface hardness of 2-4H. S44 Curing and Solidification: The curing and solidification time is set to 3-5 days; S45 Coating Treatment: After the first coating, polishing, curing and curing of the substrate, a second coating is applied with a coating amount of 30-40 g / m². S46 Polishing Treatment: The surface is polished again using a combination of 240-mesh and 320-mesh abrasive belts to further improve the surface quality, achieving a surface finish Ra of 0.4-0.5 and a surface hardness of 3-4H. S47 Wellness: Set the duration to 5-10 days to obtain hardened formaldehyde-free plywood and formaldehyde-free blockboard substrates.

5. The formaldehyde-free decorative panel according to claim 4, characterized in that, The preparation of the high-surface-performance formaldehyde-free paper includes the following specific steps: S51 Raw material preparation: 76-82 parts acrylic emulsion, 15-20 parts melamine resin, 0.3-0.4 parts catalyst p-benzenesulfonic acid, 0.12-0.18 parts wetting agent, 0.1-0.13 parts penetrant, 0.1-0.2 parts defoamer, 3-8.2 parts deionized water, pre-impregnated paper, and water-based coating. The water-based coating is a water-based acrylic emulsion, water-based polyurethane, or polyacrylate. Preparation of S52 waterborne amino resin: S521 Weigh a certain amount of melamine resin according to the formula, add deionized water, and dilute the melamine resin to a mass fraction of 50-60%; S522: Add the diluted melamine resin to the measured amount of acrylic emulsion, stir at high speed of 800-1200 rpm for 4-5 minutes, and then reduce the speed. S523 is then mixed with catalyst, wetting agent, penetrant, defoamer and other appropriate additives, and stirred until homogeneous to obtain water-based amino resin for later use. S53 roller coating process: S531 is coated using a coating roller, with the prepared water-based amino resin injected between the coating rollers. S532 prepreg paper is horizontally unwound by an unwinding machine, and after passing through a roll coating machine, it is coated with a water-based coating to obtain a surface coating. S533 is dried in a dryer to obtain formaldehyde-free decorative paper with certain decorative properties and surface performance, namely, the high surface performance formaldehyde-free paper.

6. The formaldehyde-free decorative panel according to claim 5, characterized in that, The specific steps involved in the fabrication of the formaldehyde-free decorative panel composite include: S61 Dust Removal: The substrate undergoes three dust removal processes: electrostatic removal, brush removal, and air blowing. S62 Coating and Lamination: The adhesive used is polyvinyl acetate or formaldehyde-free, fast-curing polyurethane adhesive, with a coating amount of 30-40 g / m². 2 The feed speed is 10-20 meters per minute; S63 Roller Pressing: Set the roller pressing pressure to 0.7-0.9mm and the time to 2-10 minutes; S64 Trim: Remove excess rough edges from the paper to ensure consistent dimensions; S65 curing: Set the curing time to 24-48 hours to obtain the formaldehyde-free decorative panel.

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