Three-section digital coating process for odor-free anti-aging crack-resistant solid wood water paint board

Abstract

The invention relates to the technical field of digital coating of solid wood, in particular to a three-section digital coating process for an odor-free anti-aging crack-resistant solid wood water paint board. The process comprises the following steps: S1, working section: base coat composite coating: coating four base coat coatings; s2, working section: performing digital pattern composite coating, including coating of three floating coatings; and S3, a water paint surface layer is subjected to composite coating, wherein coating of four surface coating layers is included. According to the three-section type digital coating technology, the problems that a solid wood paint panel is poor in aging resistance and crack resistance and poor in odor removal effect, and the stability and consistency of the optimal effect cannot be guaranteed by the solid wood feeling are solved; and the problems that the paint surface feeling of a solid wood paint panel of a pure UV coating system is not high-grade and high-end enough, and the surface effect, the surface performance and the environment-friendly and odor-removing performance are not extremely high enough are solved.

Description

Technical Field

[0001] The present application relates to the technical field of digital painting of solid wood, and in particular to a three-stage digital painting process of a water-based paint board of solid wood that is odor-free, aging-resistant, and crack-resistant. Background Art

[0002] Solid wood lacquer panels are the main materials for dark precious hardwood furniture and high-end custom furniture. Traditional solid wood lacquer panels are made of man-made boards with precious and high-quality decorative veneer veneers and processed with wood paint coatings. Among them, the main function of the precious and high-quality decorative veneer veneer layer is to provide decorative texture, texture and pattern color for the surface decoration of the solid wood lacquer panel, and the main function of the wood paint coating is to provide or further strengthen, optimize and upgrade the surface physical and chemical properties of the product (including but not limited to: paint film hardness, abrasion resistance, scratch resistance, resistance to corrosion by pollutants, crack resistance, aging resistance, yellowing resistance and other protective properties or durability) and surface decorative properties (including but not limited to: gloss, color, clarity, transparency, real naturalness, three-dimensional sense, phantom motion, skin touch and feel and other visual and tactile decorative properties). The above-mentioned traditional solid wood lacquer panels, although they have many excellent features and advantages, also have the following difficulties and pain points that need to be studied and solved urgently.

[0003] The first problem is: the paint surface of traditional solid wood paint panels is overly dependent on traditional solvent-based wood coatings [including but not limited to polyurethane wood coatings (PU paints), alkyd wood coatings (AC paints), nitrocellulose wood coatings (NC paints), etc.], and traditional solvent-based wood coatings perform poorly in terms of odor, VOCs and other harmful substances limits and aging resistance. As a result, the health, safety and environmental protection performance of its products is difficult to meet people's strong demand for health, environmental protection and a better life, especially the requirements for ultra-low release of toxic and harmful substances such as zero odor, formaldehyde-free, and low VOCs, as well as people's strong demand for non-toxic, harmless, odor-free, ready to move in, and no need for long-term ventilation and long-term idle deodorization.

[0004] The second problem is that the solid wood feel of traditional solid wood lacquer panels is overly dependent on precious and high-quality decorative veneer veneers. Without precious and high-quality decorative veneer veneers, it is impossible to obtain decorative effects such as decorative texture, texture, and decorative pattern color in the surface decoration. The precious and high-quality decorative veneer veneer is overly dependent on precious natural wood resources, as well as the precious and high-quality veneer processing industry and the artificial board veneer industry that are manually produced. As a result, traditional solid wood lacquer panels are not only difficult to industrialize and mass produce, with extremely high production costs, but also difficult to meet the current popular personalized customization needs and the service needs of rapid design and rapid production and delivery.

[0005] The third problem is: the solid wood feel and wood cortex texture of traditional solid wood paint panels rely on the surface decorative effect (grain, texture and pattern color) obtained from the precious and high-quality decorative veneer layer. Because it comes from different logs or wood blocks and wood from different origins, different varieties, different ages, and different parts of the tree trunk, there are natural and innate differences. It can only guarantee similar decorative effects but cannot guarantee the same and identical decorative effects. It is difficult to ensure the consistency and stability of the surface decorative effects. There are often obvious deviations in the surface decorative effects such as texture, texture and color patterns, which makes it difficult to meet the production needs, market demands and the ultimate aesthetics of home decoration for large-scale industrialization, large-scale quantification and strict standardization.

[0006] The Chinese patent application number 202310144967.6 provides a finishing process for CNC color matching decoration of 3D visible-porous wood grain paint on the surface of artificial boards, which solves the above problems to a certain extent. However, the primary technical feature of the patent is that a composite coating system of pure UV wood coatings is used instead of a composite coating system of solvent-based wood coatings; another notable feature of the patent is that the natural texture of the decorative veneer layer is replaced by the surface film-pressed texture or printed texture of the 3D texture-modeling UV topcoat coating, and the natural texture and decorative color pattern of the decorative veneer layer are replaced by a UV ink color composite coating system. However, while solving the above problems, the above patent and its solution also bring new problems, namely: (1) The paint surface of the pure UV roller coating is not high-end and high-grade: it cannot achieve the high-end effect of extremely delicate, warm and high-grade when viewed from a distance, close up, microscopically and macroscopically, visually and tactilely, and the harmonious integration of real natural feeling and design sense; (2) The real wood effect of pure UV ink color coating + pure UV-3D simulated texture coating is not real and natural enough: the clarity, synchronization, vividness and realism of the texture and texture are not enough, and the real wood texture effect of seeing the wood but not the paint cannot be achieved. In particular, the open paint surface has defects and cannot achieve the ultimate visual and tactile effects; (3) Insufficient aging and crack resistance: Pure UV coatings are hard and brittle, and have poor aging resistance such as yellowing resistance, oxidation resistance, and crack resistance. In order to take into account the UV radiation curing efficiency, large doses of ultraviolet light absorbers cannot be used. When the UV coating that is susceptible to photothermal and photooxidation is the outermost layer and is directly exposed and in direct contact with external environments such as light, oxygen, heat, and moisture, the UV paint coating will be easily oxidized and decomposed or photothermal radiation will crack to produce various color-developing groups and functional groups, causing the coating to turn yellow, black, discolor, age, and crack, affecting the decorative effect.

[0007] (4) The deodorizing effect is not good enough: The composite coating of the pure UV system and the cured coating of its UV-3D topcoat are directly exposed to the outermost layer of the board surface, causing the residual low-boiling point VOCs such as photoinitiators to evaporate and produce a slight odor. This cannot meet the application scenarios such as wardrobes and cabinets due to the existence of closed spaces or the high utilization rate of boards, which can easily lead to the accumulation of odor substances with the accumulation of board usage and the sealing time, and become obvious odor. It is difficult for the odor level of the product surface coating to stably reach the deodorizing level of ≤1, and it is also difficult for the VOCs emission to stably reach the ultra-low emission level required by the green product standard (TVOC emission ≤0.100mg / m 3 ).

[0008] (5) The surface finishing effect of this coating process has obvious limitations. The closed paint surface has a certain degree of haziness, lack of transparency and clarity, and the open paint surface has a certain degree of texture deviation, insufficient synchronization, and sunken texture has spots and bright marks and other appearance quality defects. As a result, the coating effect can only reach the simulation level, but cannot achieve the ultimate effect that exceeds the master effect. Summary of the invention

[0009] The present application provides a three-stage digital painting process for odorless, aging-resistant, and crack-resistant solid wood water-based paint panels to solve the problems raised in the above-mentioned background technology.

[0010] In order to solve the above problems, the present application provides a three-stage digital painting process for a odorless, aging-resistant, and crack-resistant solid wood water-based paint board, which includes the following steps: S1 section: Primer composite coating: S101, coating of the first primer: after sanding and dust removal on the surface of the substrate, roll-coat the UV odor-free, yellowing-resistant, high-adhesion clear primer and adhesive putty clear primer in sequence; S102, coating of the second primer: roll-coat UV-free, odor-free, yellowing-resistant, white solid color primer on the first primer; S103, coating of the third primer: roll-coat UV odor-free, yellowing-resistant, color-correcting solid-color primer on the second primer; S104, coating of the fourth primer: roll-coat the UV odor-free, yellowing-resistant, color-correcting solid-color primer on the third primer; S2 section: Digital color composite coating: S201, coating of the first intermediate coating: roller-coat UV odor-free, yellowing-resistant, high-adhesion clear primer on the fourth primer coating of S104; S202, coating of the second intermediate coating: spraying UV-clear, highly resistant to discoloration yellow, magenta, cyan, and black solid color inks on the first intermediate coating respectively; S203, coating of the third intermediate coating: roll-coat UV odor-free, yellowing-resistant sanding clear primer or hardened clear primer on the second intermediate coating; S3 section: water paint surface composite coating: S301, coating of the first topcoat: Roller-coat UV odor-free, yellowing-resistant, high-adhesion clear primer on top of the third midcoat; S302, coating of the second topcoat: coating the first topcoat with UV odor-free, yellowing-resistant, synchronous texture clear topcoat by roller coating; S303, coating of the third topcoat: after rolling the water-based UV odor-free, yellowing-resistant, color-correcting and clear primer on the second topcoat, heat and dehumidify and dry at 80-100°C for 2 minutes; S304, coating of the fourth topcoat: spray a water-based, odorless, yellowing-resistant clear topcoat on top of the third topcoat, first dry the surface in an infrared drying tunnel at 35-45°C for 10 minutes, then dry the inner layer in a heated and dehumidified vertical drying room at 45-60°C for 90-120 minutes.

[0011] Preferably, in S1, the coating speed of the primer composite coating is 16-18 m / min; In S2, the painting speed of digital color composite painting is 24~26m / min; In S3, the coating speed of the water paint surface composite coating is 5~6m / min.

[0012] Preferably, the substrate is a hard, dense, crack-resistant, closed, real veneer-faced, formaldehyde-free, odor-free artificial board.

[0013] Preferably, in the S1 section, among the UV odor-free, yellowing-resistant, high-adhesion clear primer, the adhesion putty clear primer, the UV odor-free, yellowing-resistant, white solid color primer, the UV odor-free, yellowing-resistant, color-correcting solid color primer, and the UV odor-free, yellowing-resistant, color-correcting solid color primer: The long-lasting anti-yellowing multifunctional additive used is a single crystal rutile type pigment-grade and micron-grade ultrafine particle titanium dioxide with a particle size of 100-400nm. Calculated by weight, the addition amount of the long-lasting anti-yellowing multifunctional additive accounts for 5-8% of the weight of the above-mentioned primers. The UV resin used is aliphatic non-aromatic polyurethane acrylate resin, silicone-modified or polyurethane-modified epoxy acrylic resin, pure acrylic resin, or a mixture thereof. Calculated by weight, the amount of UV resin added accounts for 46-65% of the weight of the above primers; The UV active monomer used is TMPTA trimethylolpropane acrylate, TPGDA tripropylene glycol acrylate, DPGDA dipropylene glycol diacrylate, or a mixture thereof. Calculated by weight, the amount of the UV active monomer added accounts for 25-45% of the weight of the above primers. The photoinitiator used is TPO 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, BMF methyl benzoylformate, ITX isopropylthioxanthone, or a mixture thereof. Calculated by weight, the amount of the photoinitiator added accounts for 2-6% of the weight of the above primers.

[0014] Preferably, in the UV-clear, highly resistant to discoloration yellow, magenta, cyan, and black solid color inks: The long-lasting anti-yellowing multifunctional additive used is a single crystal rutile type ultrafine particle powder nano titanium dioxide with a particle size of 10-100nm. Calculated by weight, the addition amount of the long-lasting anti-yellowing multifunctional additive accounts for 0.5-5% of the mass of the above-mentioned UV clean odor high color-discoloration-resistant yellow, magenta, cyan, and black solid color inks; The UV resin used is aliphatic non-aromatic polyurethane acrylate resin, fatty acid modified or polyurethane modified or silicone modified epoxy acrylic resin, pure acrylic resin, or a mixture thereof. Calculated by weight, the amount of UV resin added accounts for 30-60% of the mass of UV pure high color fastness yellow, magenta, cyan, black solid color ink; The photoinitiator used is TPO 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, BMF methyl benzoylformate, ITX isopropylthioxanthone, or a mixture thereof. Calculated by weight, the amount of the photoinitiator added accounts for 2-5% of the weight of the above primers.

[0015] Preferably, in the fatty acid-modified, polyurethane-modified or silicone-modified epoxy acrylic resin: The preparation method of fatty acid modified epoxy acrylic resin comprises the following steps: 100 parts of bisphenol A epoxy resin and 0.1 parts of hydroquinone were mixed, melted at 90°C, 30 parts of oleic acid were added under stirring, the temperature was raised to 110°C for reaction for 2 hours, the temperature was lowered to 80°C, 25 parts of acrylic acid and 1 part of triethylamine were added dropwise, and the mixture was reacted at 90°C for 3 hours to complete the preparation; The preparation method of polyurethane modified epoxy acrylic resin comprises the following steps: Add 20 parts of hydroxyl-terminated polyurethane prepolymer and 0.2 parts of dibutyltin dilaurate to 100 parts of epoxy acrylic resin heated at 60°C, react for 1.5 hours, then add 3 parts of 1-hydroxy-cyclohexyl-phenyl ketone and 10 parts of tripropylene glycol diacrylate, and stir evenly; The preparation method of organosilicon-modified epoxy acrylic resin comprises the following steps: To 100 parts of epoxy acrylic resin heated at 80°C, add 10 parts of γ-methacryloxypropyltrimethoxysilane, cool to 50°C, add 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 10 parts of isooctyl acrylate, and stir well.

[0016] Preferably, in S302, the UV odor-free, yellowing-resistant, synchronously textured clear topcoat includes, by mass, 20 to 25 parts of polyurethane acrylic resin; 25 to 40 parts of epoxy acrylic resin; 30 to 40 parts of an equal mixture of DPGDA dipropylene glycol diacrylate, TPGDA tripropylene glycol acrylate, TMPTA trimethylolpropane acrylate, and HEMA hydroxyethyl methacrylate; 4 to 7 parts of an equal mixture of MBF, TPO, and ITX; 0.2 to 0.4 parts of a bubble-breaking polymer solution; and 0.4 to 0.6 parts of a polysiloxane-ether copolymer solution.

[0017] Preferably, in S304, the water-based odorless yellowing-resistant clear topcoat comprises, by weight: 100 parts of a composition of an aqueous acrylic modified polyurethane resin and an aqueous polyurethane dispersion; 5~15 parts of curing agent; 10~20 parts of diluent; 0.2~2.0 parts of UV absorbers, anti-aging and antioxidant sunscreen additives; 3.0~6.0 parts of VOCs purification and deodorizing agent; 1.0~3.0 parts of additives.

[0018] The curing agent is a composition of a hydrophilically modified aliphatic polyisocyanate and a hydrophilically modified alicyclic polyisocyanate; The diluent is purified water; The ultraviolet light absorber, anti-aging and antioxidant sunscreen aid is a combination of 2-hydroxy-4-methoxybenzophenone, 4-hydroxy-2,2,6,6-tetramethylpiperidine, diethylaminohydroxybenzoyl hexyl benzoate, ethylhexyl methoxycinnamate, and rutile gas-phase nano titanium dioxide and nano zinc dioxide; The VOCs purification and deodorizing agent is a composition of nano silicon dioxide, nano photocatalyst, chitosan and ethylene urea in equal proportions.

[0019] Preferably, in S101, the coating amount of the UV odor-free, yellowing-resistant, high-adhesion clear primer is 15-25 g / m 2 , the coating amount of adhesive putty clear primer is 25~35g / m 2 , the UVA energy value of UV light radiation is 200~400mJ / cm 2 , UVV energy value is 300~600mJ / cm 2 ; In S102 and S103, the primer coating amount is 20-30 g / m 2 , the UVA energy value of UV light radiation is 150~350mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; In S104, the primer coating amount is 20-30 g / m 2 , the UVA energy value of UV light radiation is 250~400mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; In S201, the primer coating amount is 10-20 g / m 2 , the UVA energy value of UV light radiation is 150~300mJ / cm 2 , UVV energy value is 200~400mJ / cm 2 ; In S202, the ink coating amount is 1-10 g / m 2 , the UVA energy value of UV light radiation is 200~400mJ / cm 2 , UVV energy value is 300~600mJ / cm 2 ; In S203, the primer coating amount is 15-25 g / m 2 The UVA energy value in UV light radiation is 300~500 mJ / cm 2 , UVV energy value is 400~800 mJ / cm 2 ; In S301, the primer coating amount is 15-25 g / m 2 , the UVA energy value of UV light radiation is 150~300mJ / cm 2 , UVV energy value is 200~400mJ / cm 2 ; In S302, the topcoat coating amount is 150-250 g / m 2 , the UVA energy value of UV light radiation is 300~400mJ / cm 2 、UVV energy value is 400~600mJ / cm 2 ; In S303, the primer coating amount is 30-45 g / m 2 , the UVA energy value of UV light radiation is 300~400mJ / cm 2 、UVV energy value is 400~600mJ / cm 2 .

[0020] The beneficial effects of the technical solution provided by this application include: (1) The application of odorless and aging-resistant modified coatings and new digital water-based paint coating processes has solved the problems of low-grade paint surface, low-realistic and natural wood texture, and poor odorless, aging-resistant and crack-resistant performance. Use odorless and aging-resistant additives (5%~20% rutile micronized titanium dioxide) and simulation enhancers (0.5~5.0% rutile vapor-phase nano-titanium dioxide) in coatings and inks; use the "ultraviolet light absorption and shielding effect" of micronized titanium dioxide to improve the odorless and aging-resistant performance of coatings; use the "angle-dependent color and light refraction effect" of nano-titanium dioxide to significantly improve the printing clarity, simulation, liveliness and real wood texture of ink jet printing color pattern coatings; use the texture modeling synchronization process to improve the synchronization degree of UV-3D topcoat texture; use the modified water-based paint process (adding simulation enhancers, odorless purification functional additives and aging-resistant additives) to significantly improve the high-grade feel of the paint surface, the real wood texture, and odorless, aging-resistant and crack-resistant performance.

[0021] (2) The technical requirements for the substrate veneer layer have been improved, making the subsequent coating process simpler and more cost-effective. By using a closed crack-resistant substrate and a odor-free, aging-resistant, and crack-resistant coating process, a variety of unique paint effects such as closed, open, semi-open, and customized special effects can be flexibly obtained on demand. In particular, the surface veneer layer is preferably a fast-growing artificial forest poplar original color ordinary technical veneer rather than a precious and high-quality natural veneer, and does not involve endangered animal and plant species and controlled wood, which can avoid technical barriers and tariff barriers to export to the European and American markets.

[0022] (3) The coating process of the primer composite coating is simplified, and multiple processes such as brushed pore treatment on the substrate surface, UV roller coating of ordinary putty, and sanding primer are omitted and saved. While achieving significant improvements in the primer effect and odor-free, aging-resistant and crack-resistant performance, it can also achieve significant economic effects of cost reduction, efficiency improvement, and value-added.

[0023] (4) Replacing the pure UV coating system with a "hybrid coating system of UV primer + UV midcoat + water-based paint topcoat" is not only an upgrade of the traditional UV coating process, but also a digital improvement and innovative breakthrough of the traditional water-based paint coating process. It not only solves the problem of poor yellowing resistance, oxidation resistance, cracking resistance and other aging resistance of pure UV coatings, but also overcomes the problem that the pure UV coating system cannot add large doses of ultraviolet light absorbers in order to take into account the efficiency of light radiation curing. When the UV coating that is easily photothermal and photooxidized is the outermost layer and is directly exposed and in direct contact with the external environment such as light, oxygen, heat, and moisture, the UV topcoat coating will be easily oxidized and decomposed or photothermal radiation will crack to produce various color-developing groups and functional groups, resulting in the problem of yellowing, blackening, discoloration, aging and cracking of the coating, which affects the surface decorative effect. It also makes full use of the flexibility of the water-based paint coating, solves the problems of high hardness, poor aging resistance, and easy cracking and edge collapse of the pure UV coating, and realizes the high performance and high cost performance (digitalization) of water-based paint coating.

[0024] (5) The use of a "hybrid coating system of UV primer + UV midcoat + water-based topcoat" instead of a pure UV coating system overcomes the problem that the composite coating of the pure UV system and the cured coating of its UV-3D topcoat are directly exposed to the outermost layer of the board surface, causing the residual low-boiling-point VOCs such as photoinitiators to evaporate and produce a slight odor, but cannot meet the problem of application scenarios such as wardrobes and cabinets where there are closed spaces or the board usage rate is large, which easily leads to odorous substances accumulating with the amount of board used and the closed time, and becoming odorous. The product of this invention has an odor level of the surface coating that can stably reach a net odor level of ≤1, and the VOCs emission can stably reach the ultra-low emission level required by the green product standard (TVOC emission ≤0.100mg / m 3 ), and no formaldehyde substances are added, and it has the special effect of purifying the air quality in the space where the product is used.

[0025] (6) The outermost coating layer is improved from roller-coated UV topcoat to spray-coated water-based paint, which is not only healthier and odorless, but also has a more delicate, high-end and high-grade tactile texture. The added water-based UV color correction varnish and spray-coated water-based paint surface can enhance the color correction effect and transparency of the surface coating. There is no limitation of conventional UV-3D coating process. The closed paint surface does not have the problems of haziness, lack of transparency and clarity. The open paint surface does not have the appearance quality defects such as texture deviation, insufficient synchronization, sunken texture spots and bright marks, so that the coating effect can far exceed the simulation level and the master plate effect, and can achieve the ultimate excellent effect.

[0026] (7) The present invention has created a new three-stage digital coating process, which not only scientifically meets the process characteristics of various functional coatings (avoiding direct contact between water-based paint and substrate, causing the substrate to absorb water and there are risks of swelling, cracking, deformation, etc.), but also enables each coating to obtain a suitable curing effect, ensuring that the performance of each coating can meet the technical requirements, achieve the effect of seeing the wood but not the paint, with a strong sense of real wood and a relatively weak sense of paint surface, and avoid residual odor or performance reduction due to incomplete curing of the coating; it can also maximize the operating efficiency of each process section, ensure the optimization of output, efficiency and cost, and achieve a better process effect of energy saving, consumption reduction and efficiency improvement. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 In the three-stage digital coating process of the odor-free, aging-resistant, and crack-resistant solid wood water-painted board provided in this application, the S1 stage: the production process flow of the primer composite coating; Figure 2 In the three-stage digital coating process of the odor-free, aging-resistant, and crack-resistant solid wood water-painted board provided in this application, the S2 stage: the production process flow of digital color composite coating; Figure 3 In the three-stage digital coating process of the odor-free, aging-resistant, and crack-resistant solid wood water-painted board provided in this application, the S3 stage: the production process flow of the composite coating of the water-painted surface layer; Figure 4 Sample diagrams of Example 1, Comparative Example 1-1, Comparative Example 1-2, and Comparative Example 1-3 provided in this application; Figure 5 Sample diagrams of Example 2, Comparative Example 2-1, Comparative Example 2-2, and Comparative Example 2-3 provided in this application. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0030] See also Figures 1 to 5As shown, the present application provides a three-stage digital painting process for a odor-free, aging-resistant, and crack-resistant solid wood water-based paint board, which includes the following steps: S1 section: primer composite coating, specifically including 4 primer coatings, the coating speed is 16~18m / min: S101, coating of the first primer: after sanding and dusting the substrate surface, roll-coat the UV clean, yellowing-resistant, high-adhesion clear primer and the adhesive putty clear primer in turn, and irradiate with UV light. After drying and curing to 70% of the curing degree, no storage and curing is required. Use a 400# sanding belt abrasive to finely sand the paint film surface. The coating amount of the UV clean, yellowing-resistant, high-adhesion clear primer is 15~25g / m 2 , the coating amount of adhesive putty clear primer is 25~35g / m 2 , the UVA energy value of UV light radiation is 200~400mJ / cm 2 , UVV energy value is 300~600mJ / cm 2 .

[0031] S102, coating of the second primer: roll-coat the first primer with UV-free, yellowing-resistant, white solid color primer, irradiate with UV light, dry and cure to 50% curing degree, with the primer coating amount of 20-30g / m 2 , the UVA energy value of UV light radiation is 150~350mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; S103, coating of the third primer: roll-coat the UV odor-free, yellowing-resistant, color-correcting solid-color primer on the second primer, and irradiate with UV light, dry and cure to 50% of the curing degree, where the primer coating amount is 20~30g / m 2 , the UVA energy value of UV light radiation is 150~350mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; S104, coating of the fourth primer: roll-coat the UV odor-free, yellowing-resistant, color-correcting solid-color primer on the third primer, and irradiate with UV light. After drying and curing to 70% of the curing degree, store it for at least 24 hours to maintain the health and deodorize it. Use a 400# sanding belt abrasive to finely sand the paint film surface. The primer coating amount is 20~30g / m 2 , the UVA energy value of UV light radiation is 250~400mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; S2 section: Digital color composite coating, including three intermediate coating layers, with a coating speed of 24~26m / min: S201, coating of the first intermediate coating: Roller-coat UV odor-free, yellowing-resistant, high-adhesion clear primer on the fourth primer coating of S104, and irradiate with UV light, dry and cure to 50% curing degree, where the primer coating amount is 10~20g / m 2 , the UVA energy value of UV light radiation is 150~300mJ / cm 2 、UVV energy value is 200~400mJ / cm 2 ; S202, coating of the second intermediate coating: UV-clear, highly discoloration-resistant yellow, magenta, cyan, and black solid color inks are sprayed on the first intermediate coating, and then irradiated with UV light to dry and cure to a curing degree of about 50%. The ink coating amount is 1-10 g / m 2 (The specific ink consumption is determined by the pattern and color of the printed design). The actual coating amount varies slightly with the depth of the color of the pattern. The UVA energy value of UV light radiation is 200~400mJ / cm 2 , UVV energy value is 300~600mJ / cm 2 ; S203, coating of the third midcoat: roll-coat UV odor-free yellowing-resistant sanding clear primer or hardened clear primer on the second midcoat, and irradiate with UV light. After drying and curing to 70% curing degree, store for at least 12 hours to maintain health and deodorize, and then use 400~600# sanding belt abrasives to finely sand the paint film surface. The primer coating amount is 15~25g / m 2 In UV light radiation, the UVA energy value is 300~500 mJ / cm 2 、UVV energy value is 400~800 mJ / cm 2 ; S3 section: water paint surface composite coating, specifically including 4 topcoat coatings, the coating speed is 5~6m / min: S301, coating of the first topcoat: Roller-coat UV odor-free, yellowing-resistant, high-adhesion clear primer on the third midcoat, and irradiate with UV light, dry and cure to 50% curing degree, where the primer coating amount is 15~25g / m 2 , the UVA energy value of UV light radiation is 150~300mJ / cm 2 , UVV energy value is 200~400mJ / cm 2 ; S302, coating of the second topcoat: on the first topcoat, apply UV odor-free, yellowing-resistant, synchronous texture clear topcoat with a roller, and irradiate with UV light, dry and cure to 90% of the curing degree, and then use a 600# sanding belt abrasive to finely sand the paint film surface, with the topcoat coating amount of 150~250g / m 2 , the UVA energy value of UV light radiation is 300~400mJ / cm 2 、UVV energy value is 400~600mJ / cm 2 ; Furthermore, the four edge lines of the decorative surface where the second topcoat layer is located need to be ground (the grinding width should be ≤0.5mm).

[0032] S303, coating of the third topcoat: after rolling the water-based UV odor-free, yellowing-resistant, color-correcting clear primer on the second topcoat, heat and dehumidify and dry at 80-100°C for 2 minutes, then irradiate with UV light and dry and cure to 70% curing degree, the primer coating amount is 30-45g / m 2 , the UVA energy value of UV light radiation is 300~400mJ / cm 2 、UVV energy value is 400~600mJ / cm 2 ; S304, coating of the fourth topcoat: spray a water-based, odorless, yellowing-resistant clear topcoat on top of the third topcoat, first dry the surface in an infrared drying tunnel at 35-45°C for 10 minutes, then dry the inner layer in a heated and dehumidified vertical drying room at 45-60°C for 90-120 minutes, and after drying and curing to a curing degree of more than 90%, store and cure for more than 24 hours to complete the three-stage digital coating.

[0033] In some embodiments, in S101, S201 and S301, the UV odor-free, yellowing-resistant, high-adhesion clear primer comprises the following components in parts by weight: 20-25 parts of epoxy acrylate resin, 15-20 parts of polyester acrylate resin, 10-15 parts of amino acrylate resin, 8-10 parts of dipropylene glycol diacrylate, 12-15 parts of tripropylene glycol diacrylate, 10-15 parts of trihydroxymethylpropane triacrylate, 3-4 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 3-4 parts of 1-hydroxycyclohexyl phenyl ketone, 5-10 parts of nano silicon dioxide, 5-10 parts of nano titanium dioxide, 0.01-1 part of adhesion promoter, 0.01-1 part of dispersant, 0.01-1 part of wetting agent, 0.01-1 part of defoaming agent, 0.01-1 part of cosolvent, and 0.01-1 part of anti-settling agent.

[0034] In some embodiments, in the S1 section, the coating speed of the primer composite coating is 16-18 m / min; In the S2 section, the coating speed of digital color composite coating is 24~26m / min; In the S3 section, the coating speed of the water-based paint surface composite coating is 5~6m / min.

[0035] In some embodiments, the substrate is a hard, dense, crack-resistant, closed, real wood veneer-faced, formaldehyde-free, odor-free artificial board.

[0036] Furthermore, the base material should preferably be an odor-free formaldehyde-free artificial board base material with an odor level ≤ 1, and specifically can be further preferably a veneer-faced plywood or veneer-faced particleboard made of all eucalyptus or all poplar wood made of Sanke Tree Green Core formaldehyde-free glue or MDI formaldehyde-free glue. Formaldehyde-containing plywood and particleboard made of miscellaneous wood, recycled wood, pine, cypress, camphor wood, fir, toon wood, etc., which have obvious odor characteristics and odorous tree species, should not be used.

[0037] Secondly, the closed substrate of the above-mentioned odorless, formaldehyde-free, aging-resistant digital solid wood water-painted board is preferably a veneer plywood or veneer particleboard, and the veneer veneer used is a high-quality grade with standardized surface conditions (no color difference, no missing silk, no black lines and other appearance defects) and a dense type (density controlled at 0.60~0.70g / cm 3、 The density is too small and it is not hard enough, and the density is too large and it is not flexible and crack-resistant.) Crack-resistant and aging-resistant original color first-grade poplar veneer reorganization layering fine line straight grain sliced ​​closed type (without wood eyes and tube holes) veneer. The wood texture of the veneer of the substrate veneer layer is used to enhance the real wood texture of the surface touch and feel of the board. The high density, high hardness and high crack resistance of the veneer of the substrate veneer layer are used to appropriately reduce the hardness requirements of the finishing coating, so that it can choose aliphatic resins with better flexibility and rigid molecular structure without benzene rings or aromatic rings in the molecular structure, so as to improve the aging resistance, crack resistance and stability of the finishing coating against oxidation and cracking and decomposition, and the deodorizing effect.

[0038] In some embodiments, in S101, the UV odor-free and yellowing-resistant adhesive putty clear primer comprises the following components in parts by weight: 25-30 parts of epoxy acrylate resin, 25-30 parts of amino acrylate resin, 8-10 parts of dipropylene glycol diacrylate, 12-15 parts of tripropylene glycol diacrylate, 10-15 parts of trihydroxymethylpropane triacrylate, 3-4 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 3-4 parts of 1-hydroxycyclohexyl phenyl ketone, 5-10 parts of lithopone, 5-10 parts of talc, 5-10 parts of nano silicon dioxide, 5-10 parts of nano titanium dioxide, 0.01-1 part of adhesion promoter, 0.01-1 part of dispersant, 0.01-1 part of wetting agent, 0.01-1 part of defoaming agent, 0.01-1 part of cosolvent, and 0.01-1 part of anti-settling agent.

[0039] It should be noted that in S101, the adhesion promoter is silane coupling agent KH-570, the dispersant is BYK-163, the wetting agent is BASF EFKA-3600, the defoaming agent is EFKA-2722, the cosolvent is propylene glycol methyl ether acetate (PMA), and the anti-settling agent is fumed silica.

[0040] In some embodiments, in S102, the UV odor-free, yellowing-resistant, white solid color primer comprises the following components in parts by weight: 5~20 parts of long-lasting anti-yellowing multifunctional additives, 50~70 parts of long-lasting odorless anti-yellowing UV resin (without aromatic rings and double bonds in the molecular structure, good transparency, not easy to break bonds and turn yellow under ultraviolet light, good color retention, light retention, heat resistance and weather resistance), 20~40 parts of UV active monomers, 2~6 parts of photoinitiator; The UV odor-free, yellowing-resistant, color-correcting solid color primer used in S103 and S104 includes the following components by weight: 5~20 parts of long-lasting yellowing-resistant multifunctional additives, 50~70 parts of long-lasting odorless yellowing-resistant UV resin, 20~40 parts of UV active monomers, and 2~6 parts of photoinitiators.

[0041] It should be noted that the difference between the UV clean odor and yellowing resistant color correction solid color primer and the UV clean odor and yellowing resistant white solid color primer lies in the color of the pigment.

[0042] Among them, the long-lasting anti-yellowing multifunctional additive is rutile-type pigment-grade and micron-grade titanium dioxide, which has the functions of UV shielding, sun protection, light-oxygen-heat stability, and can effectively achieve yellowing resistance. The particle size of titanium dioxide is 100~400nm; The long-lasting, odorless, and yellowing-resistant UV resin is a mixture of equal proportions of aliphatic non-aromatic polyurethane acrylate resin (Houding HD-200 is used in this application), silicone-modified or polyurethane-modified epoxy acrylic resin, and pure acrylic resin; The UV active monomer is a mixture of tetramethylpropylenediamine (TMPDA), tripropylene glycol diacrylate (TPGDA), and dipropylene glycol diacrylate (DPGDA) in equal proportions; The photoinitiator has long-lasting yellowing resistance and ultra-low odor, and is specifically a mixture of 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, methyl benzoylformate and isopropylthioxanthone in equal proportions.

[0043] Furthermore, in the long-lasting, odorless and yellowing-resistant UV resin, the preparation method of the silicone-modified epoxy acrylic resin is as follows: 10 parts of γ-methacryloxypropyltrimethoxysilane are added dropwise to 100 parts of epoxy acrylic resin heated at 80°C, and after cooling to 50°C, 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 10 parts of isooctyl acrylate are added and stirred evenly.

[0044] In the long-lasting, odorless, yellowing-resistant UV resin, the preparation method of polyurethane-modified epoxy acrylic resin is as follows: add 20 parts of terminal hydroxyl polyurethane prepolymer and 0.2 parts of dibutyltin dilaurate to 100 parts of epoxy acrylic resin heated at 60°C, react for 1.5 hours, add 3 parts of 1-hydroxy-cyclohexyl-phenyl ketone and 10 parts of tripropylene glycol diacrylate, and stir evenly.

[0045] In some embodiments, in S202, the UV resin used in the UV-clear, highly discoloration-resistant yellow, magenta, cyan, and black solid color inks is an equal proportion mixture of aliphatic non-aromatic polyurethane acrylate resin, modified epoxy acrylic resin, and pure acrylic resin (polyester acrylic resin and vinyl resin with poor yellowing resistance cannot be used); it should be noted that the modified epoxy acrylic resin used here is the modified epoxy acrylic resin in the above-mentioned S103 and S104.

[0046] Wherein, for fatty acid modified epoxy acrylic resin, its preparation method is as follows: Mix 100 parts of bisphenol A epoxy resin with 0.1 parts of hydroquinone, melt at 90°C, add 30 parts of oleic acid (dropped in 1 hour) under stirring, heat to 110°C and react for 2 hours, cool to 80°C, drop 25 parts of acrylic acid and 1 part of triethylamine, and react at 90°C for 3 hours to complete the preparation.

[0047] The photoinitiator used is a mixture of MBF (methyl benzoylformate), TPO (2,4,6-trimethylbenzoyl-diphenylphosphine oxide), and ITX (isopropylthioxanthone) in equal proportions. Other conventional photoinitiators and their mixtures such as 1173, 184, 651, BP, etc., which have poor yellowing resistance and odor-free effects, or have obvious odors, or have poor yellowing resistance, cannot be used.

[0048] The long-lasting yellowing-resistant multifunctional additive here has the properties of long-lasting yellowing resistance, UV shielding, covering, absorbing, sun-proof, light-oxygen-heat stability, and is specifically a rutile-type ultrafine particle powder nano titanium dioxide in a gas phase single crystal form in the nano-microcrystalline new material, and the particle size is 10~100nm. By utilizing the "angle-dependent color effect and light refraction effect" of the rutile-type ultrafine particle powder nano titanium dioxide in a gas phase single crystal form, the color of the UV ink pattern image coating will present different color visual effects when observed from different viewing angles, and it will be more lifelike and dynamic and statically real and natural, greatly improving the clarity and simulation of the printed pattern image.

[0049] In S203, the UV odor-free, yellowing-resistant, sanding clear primer includes the following components in parts by weight: 20-25 parts of epoxy acrylate resin, 20-25 parts of polyester acrylate resin, 10-15 parts of polyurethane acrylate resin, 8-10 parts of dipropylene glycol diacrylate, 12-15 parts of tripropylene glycol diacrylate, 10-15 parts of trihydroxymethylpropane triacrylate, 2-3 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 2-3 parts of 1-hydroxycyclohexyl phenyl ketone, 2-3 parts of 2,4,6-trimethylbenzoyl diphenoxy phosphine parts, 5-10 parts of lithopone, 5-10 parts of talc, 5-10 parts of transparent powder, 5-10 parts of nano silicon dioxide, 5-10 parts of nano titanium dioxide, 5-10 parts of zinc stearate, 0.01-1 parts of adhesion promoter, 0.01-1 parts of dispersant, 0.01-1 parts of wetting agent, 0.01-1 parts of defoaming agent, 0.01-1 parts of co-solvent, 0.01-1 parts of anti-settling agent, 2-5 parts of rutile pigment-grade and micron-grade titanium dioxide.

[0050] In S203, the hardened clear primer includes the following components in parts by weight: 10 parts of epoxy acrylate resin, 30 parts of polyurethane acrylate resin, 10 parts of amino acrylate resin, 7 parts of dipropylene glycol diacrylate, 8 parts of tripropylene glycol diacrylate, 10 parts of trihydroxymethylpropane triacrylate, 5 parts of 1,6-hexanediol diacrylate, 2 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 2 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of 2,4,6-trimethylbenzoyldiphenoxyphosphine, 5 parts of lead powder, 5 parts of nano silicon dioxide, 0.01 parts of adhesion promoter, 0.01 parts of dispersant, 0.01 parts of wetting agent, 0.01 parts of defoaming agent, 0.01 parts of co-solvent, 0.01 parts of anti-settling agent, 0.01 parts of ultraviolet light absorber, 3 parts of rutile pigment-grade and micron-grade titanium dioxide.

[0051] In S303, the UV odor-free, yellowing-resistant, color-correcting, clear primer includes the following components by weight: 25 parts of polyester acrylate resin, 15 parts of polyurethane acrylate resin, 25 parts of amino acrylate resin, 5 parts of dipropylene glycol diacrylate, 10 parts of tripropylene glycol diacrylate, 15 parts of trihydroxymethylpropane triacrylate, 3 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 3 parts of 1-hydroxycyclohexyl phenyl ketone, 3 parts of 2,4,6-trimethylbenzoyl diphenoxyphosphine, 3 parts of 2-isopropylthioxanthone, 3 parts of 4- 3 parts of ethyl dimethyl formate, 10 parts of lead powder, 10 parts of talc, 10 parts of nano silicon dioxide, 10 parts of nano titanium dioxide, 10 parts of zinc stearate, 0.1 parts of adhesion promoter, 0.1 parts of dispersant, 0.1 parts of wetting agent, 0.1 parts of defoaming agent, 0.1 parts of co-solvent, 0.1 parts of anti-settling agent, 0.1 parts of ultraviolet light absorber, 3 parts of long-lasting yellowing-resistant multifunctional additive (rutile-type pigment-grade and micron-grade titanium dioxide).

[0052] It should be noted that the adhesion promoter is silane coupling agent KH-570, the dispersant is BYK-163, the wetting agent is BASF EFKA-3600, the cosolvent is propylene glycol methyl ether acetate (PMA), the anti-settling agent is fumed silica, and the ultraviolet light absorber is BASF Tinuvin 400.

[0053] In some embodiments, in S302, the UV odor-free, yellowing-resistant, synchronous texture modeling clear topcoat comprises the following materials: 20-25 parts of polyurethane acrylic resin, 25-40 parts of epoxy acrylic resin, 30-40 parts of functional active monomer (a mixture of equal proportions of DPGDA dipropylene glycol diacrylate, TPGDA tripropylene glycol acrylate, TMPTA trimethylolpropane acrylate, and HEMA hydroxyethyl methacrylate), 4-7 parts of photoinitiator (a mixture of equal proportions of MBF, TPO, and ITX), 0.2-0.4 parts of defoaming agent (foam-breaking polymer solution), and 0.4-0.6 parts of leveling agent (polysiloxane-ether copolymer solution).

[0054] In some embodiments, in S304, the water-based odorless yellowing-resistant clear topcoat includes, by weight: 100 parts of a composition of an aqueous acrylic modified polyurethane resin and an aqueous polyurethane dispersion; 5~15 parts of curing agent; 10~20 parts of diluent; 0.2~2.0 parts of UV absorbers, anti-aging and antioxidant sunscreen additives; 3.0~6.0 parts of VOCs purification and deodorizing agent; 1.0~3.0 parts of additives.

[0055] The curing agent is a composition of a hydrophilically modified aliphatic polyisocyanate and a hydrophilically modified alicyclic polyisocyanate; The diluent is purified water; The ultraviolet light absorber, anti-aging and antioxidant sunscreen aid is a combination of 2-hydroxy-4-methoxybenzophenone, 4-hydroxy-2,2,6,6-tetramethylpiperidine, diethylaminohydroxybenzoyl hexyl benzoate, ethylhexyl methoxycinnamate, and rutile gas-phase nano titanium dioxide and nano zinc dioxide; The VOCs purification and deodorizing agent is a composition of nano silicon dioxide, nano photocatalyst, chitosan and ethylene urea in equal proportions.

[0056] Among them, the preparation of hydrophilic modified aliphatic polyisocyanate includes the following steps: after mixing 30g of hexamethylene diisocyanate (HDI) with 65mL of acetone, an acetone solution of dimethylolpropionic acid (the mass volume ratio of dimethylolpropionic acid to acetone is 1:2) is added dropwise at 50°C under a nitrogen atmosphere; after the addition is completed, the temperature is kept at 50°C for 2h under stirring; after the reaction is completed, triethylamine is added under stirring until the pH is 7.5; after the product is cooled to room temperature, it is distilled under reduced pressure to obtain the hydrophilic modified aliphatic polyisocyanate.

[0057] The preparation of hydrophilically modified alicyclic polyisocyanate includes the following steps: 40 g of isophorone diisocyanate (IPDI) is mixed with 75 mL of toluene, and then the mixture is heated to 70° C. under a nitrogen atmosphere, and then a toluene solution of polyethylene glycol (the mass volume ratio of polyethylene glycol to toluene is 2:3) is added dropwise. After the addition is completed, the reaction is maintained at 70° C. for 3 hours. After the product is cooled to room temperature, it is distilled under reduced pressure to obtain the hydrophilically modified alicyclic polyisocyanate.

[0058] Example 1 Section S1: Primer composite coating, including 4 primer coatings; see Figure 1 ; Section S2: Digital color composite coating, including 3 intermediate coating layers; see Figure 2 ; Section S3: Water-based paint surface composite coating, including 4 topcoat coatings; see Figure 3 .

[0059] Among them, in the S1 section of this embodiment: the primer composite coating parameters and process are shown in Table 1.

[0060] Table 1

[0061] The S2 section of this embodiment: the digital color composite coating parameters and process are shown in Table 2.

[0062] Table 2

[0063] The S3 section of this embodiment: the water paint surface layer composite coating parameters and process are shown in Table 3.

[0064] Table 3

[0065] The components and proportions of the functional coatings in the above-mentioned process steps are as follows: 1) UV odorless, yellowing-resistant, high adhesion clear primer: 22 parts of epoxy acrylate resin, 16 parts of polyester acrylate resin, 12 parts of amino acrylate resin, 8 parts of dipropylene glycol diacrylate, 12 parts of tripropylene glycol diacrylate, 12 parts of trihydroxymethylpropane triacrylate, 3 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 3 parts of 1-hydroxycyclohexyl phenyl ketone, 5 parts of long-lasting yellowing-resistant multifunctional additive (rutile pigment-grade and micron-grade titanium dioxide), 5 parts of nano-silica titanium, 0.1 parts of silane coupling agent KH-570, 0.05 parts of BYK-163, 0.05 parts of EFKA-2722, 0.01 parts of propylene glycol methyl ether acetate, and 0.05 parts of fumed silica.

[0066] 2) UV odorless and yellowing resistant adhesive putty clear primer: 25 parts of epoxy acrylate resin, 25 parts of amino acrylate resin, 8 parts of dipropylene glycol diacrylate, 12 parts of tripropylene glycol diacrylate, 12 parts of trihydroxymethylpropane triacrylate, 3 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 3 parts of 1-hydroxycyclohexyl phenyl ketone, 5 parts of lead powder, 5 parts of talc, 5 parts of nano-silica, 5 parts of long-lasting yellowing resistant multifunctional additive (rutile pigment-grade and micron-grade titanium dioxide), 0.1 parts of silane coupling agent KH-570, 0.05 parts of BYK-163, 0.01 parts of BASF EFKA-3600, 0.05 parts of defoaming agent EFKA-2722, 0.01 parts of propylene glycol methyl ether acetate, and 0.05 parts of fumed silica.

[0067] 3) UV odorless yellowing-resistant white solid color primer: 6 parts of long-lasting yellowing-resistant multifunctional additive (rutile pigment-grade and micron-grade titanium dioxide), 60 parts of UV resin, 35 parts of UV active monomer (a mixture of tetramethylpropylenediamine, tripropylene glycol diacrylate, and dipropylene glycol diacrylate in equal proportions), and 5 parts of photoinitiator (a mixture of MBF, TPO, and ITX in equal proportions).

[0068] The long-lasting, odor-free, yellowing-resistant UV resin is a mixture of equal proportions of Houding HD-200 polyurethane resin, silicone-modified epoxy acrylic resin and pure acrylic resin.

[0069] 4) UV odorless, yellowing-resistant, color-correcting solid color primer: 5 parts of long-lasting yellowing-resistant multifunctional additive (rutile-type pigment-grade and micron-grade titanium dioxide), 60 parts of long-lasting, odorless, yellowing-resistant UV resin, 35 parts of UV active monomer (a mixture of tetramethylpropylenediamine, tripropylene glycol diacrylate, and dipropylene glycol diacrylate in equal proportions), and 5 parts of photoinitiator (a mixture of MBF, TPO, and ITX in equal proportions).

[0070] The long-lasting, odor-free, yellowing-resistant UV resin is a mixture of equal proportions of Houding HD-200 polyurethane resin, polyurethane-modified epoxy acrylic resin and pure acrylic resin.

[0071] 5) UV odorless, highly discoloration-resistant yellow, magenta, cyan, and black solid color inks: 4 parts of long-lasting yellowing-resistant multifunctional additive (rutile pigment-grade and micron-grade titanium dioxide), 60 parts of long-lasting, odorless, yellowing-resistant UV resin, 35 parts of UV active monomer (an equal mixture of tripropylene glycol diacrylate and dipropylene glycol diacrylate), 5 parts of photoinitiator (an equal mixture of TPO, BMF, and ITX), 0.2 parts of defoaming agent (foam-breaking polymer solution), 0.5 parts of leveling agent (polysiloxane-ether copolymer solution), and 10 parts of pigment.

[0072] 6) Odorless and yellowing-resistant sanding clear primer: 20 parts of epoxy acrylate resin, 205 parts of polyester acrylate resin, 10 parts of polyurethane acrylate resin, 8 parts of dipropylene glycol diacrylate, 12 parts of tripropylene glycol diacrylate, 10-15 parts of trihydroxymethylpropane triacrylate, 2 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 2 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of 2,4,6-trimethylbenzoyl diphenoxyphosphine, 5 parts of lead powder, talc 5 parts of powder, 5 parts of transparent powder, 6 parts of nano silicon dioxide, 5 parts of nano titanium dioxide, 5 parts of zinc stearate, 0.01 parts of silane coupling agent KH-570, 0.05 parts of BYK-163, 0.1 parts of BASF EFKA-3600, 0.01 parts of defoaming agent EFKA-2722, 0.02 parts of propylene glycol methyl ether acetate, 0.05 parts of fumed silica, and 2 parts of rutile pigment-grade and micron-grade titanium dioxide.

[0073] 7) UV odorless, yellowing-resistant, synchronous textured clear topcoat: 20 parts of polyurethane acrylic resin, 25 parts of epoxy acrylic resin, 30 parts of functional active monomer (a mixture of equal proportions of DPGDA dipropylene glycol diacrylate, TPGDA tripropylene glycol acrylate, TMPTA trimethylolpropane acrylate, and HEMA hydroxyethyl methacrylate), 4 parts of photoinitiator (a mixture of equal proportions of MBF, TPO, and ITX), 0.2 parts of defoaming agent (foam-breaking polymer solution), and 0.5 parts of leveling agent (polysiloxane-ether copolymer solution).

[0074] 8) Water-based UV odor-free, yellowing-resistant, color-correcting clear primer: It differs from the UV odor-free, yellowing-resistant, color-correcting solid color primer in that it also includes 5 parts of fumed silica and 0.5 parts of a wetting agent (BASF EFKA-3600).

[0075] 9) Water-based, odorless, highly yellowing-resistant clear topcoat: 100 parts of a composition of a water-based acrylic modified polyurethane resin and a water-based polyurethane dispersion (mixed in equal proportions), 10 parts of a curing agent (a composition of a hydrophilically modified aliphatic polyisocyanate and a hydrophilically modified alicyclic polyisocyanate), 12 parts of a diluent (pure water), 0.5 parts of an ultraviolet light absorber, anti-aging and antioxidant sunscreen aid (a composition of 2-hydroxy-4-methoxybenzophenone, 4-hydroxy-2,2,6,6-tetramethylpiperidine, diethylaminohydroxybenzoyl hexyl benzoate, methoxycinnamic acid ethylhexyl ester, and rutile-type gas-phase nano-titanium dioxide and nano-zinc dioxide), 5 parts of a VOCs purification and odor-removing agent (a composition of nano-silicon dioxide, nano-titanium dioxide, chitosan, and ethylene urea in equal proportions), and 1 part of an adjuvant (0.2 parts of a defoaming agent, 0.5 parts of a leveling agent, and 0.3 parts of an anti-settling agent).

[0076] The defoaming agent is EFKA-2722, the leveling agent is BYK-333, and the anti-settling agent is fumed silica.

[0077] Example 2 The difference between this embodiment and embodiment 1 is that a hard primer is used in S203.

[0078] The components and proportions of the hard primer are as follows: 10 parts of epoxy acrylate resin, 30 parts of polyurethane acrylate resin, 10 parts of amino acrylate resin, 7 parts of dipropylene glycol diacrylate, 8 parts of tripropylene glycol diacrylate, 10 parts of trihydroxymethylpropane triacrylate, 5 parts of 1,6-hexanediol diacrylate, 2 parts of 2-hydroxy-2-methyl-1-phenylpropanone, 2 parts of 1-hydroxycyclohexyl phenyl ketone, 2 parts of 2,4,6-trimethylbenzoyldiphenoxyphosphine, 5 parts of lead powder, 5 parts of nano silicon dioxide, 0.01 parts of adhesion promoter, 0.01 parts of dispersant, 0.01 parts of wetting agent, 0.01 parts of defoaming agent, 0.01 parts of co-solvent, 0.01 parts of anti-settling agent, 0.01 parts of ultraviolet light absorber, 3 parts of rutile pigment-grade and micron-grade titanium dioxide.

[0079] Based on Example 1, the corresponding comparative examples are given: In the primer coating of the S1 section, the dosage of the long-lasting yellowing-resistant multifunctional additive of the primer in the first primer coating, the second primer coating, the third primer coating, and the fourth primer coating is adjusted, and the coating process and the curing process remain unchanged. The specific dosage adjustment is shown in Table 4.

[0080] Table 4

[0081] The results are as follows Figure 4 And as shown in Table 5.

[0082] Table 5

[0083] It can be seen that when the addition amount of the long-lasting yellowing-resistant multifunctional additive of the primer in the first primer coating, the second primer coating, the third primer coating, and the fourth primer coating increases from 5 parts to 20 parts, the surface simulation degree shows a trend of first improving and then deteriorating, while other properties all improve positively.

[0084] Based on Example 2, the corresponding comparative examples are given: In the topcoat of the water-based paint composite coating in the S3 section, the dosage of UV absorber, anti-aging and antioxidant sunscreen additives is adjusted, and the coating process and curing process remain unchanged. The specific dosage adjustment is shown in Table 6.

[0085] Table 6

[0086] The results are as follows Figure 5 And as shown in Table 7.

[0087] Table 7

[0088] It can be seen that in the topcoat of the water-based paint composite coating in the S3 section, when the addition amount of external light absorber, anti-aging and antioxidant sunscreen additives increases from 0.5 parts to 5.0 parts, the surface simulation degree shows a trend of first improving and then deteriorating, while other properties all improve positively.

[0089] From the comparative test results of the above embodiments and comparative examples, it can be seen that: (1) When the addition amount of the long-lasting yellowing-resistant multifunctional additive in the primer of the primer coating is preferably 10 to 15 parts, a better cost-effectiveness can be obtained; (2) When the amount of UV absorber, anti-aging and antioxidant sunscreen additive added to the topcoat is preferably 1 to 2 parts, a better cost-effectiveness can be obtained.

[0090] The present application provides a three-stage digital coating process for a odor-free, aging-resistant, and crack-resistant solid wood water-based paint board, in which a yellowing-resistant solid color white primer and two yellowing-resistant discoloration-correcting primers are provided in the primer coating layer, and while obtaining a correctable standardized base color, the high yellowing resistance of the solid color-correcting primer is used to cover and offset the superimposed weakening effect of the yellowing resistance of each transparent primer coating layer and the substrate layer, thereby ensuring the high yellowing resistance of the overall coating; In the digital color composite coating of the S2 section, digital color coating is used to replace and surpass the decorative colors and texture patterns on the surface of the master sample surface materials such as natural veneer and technological veneer. While obtaining the decorative effect of solid wood paint in an industrialized and standardized manner, it can also ensure that the overall coating has high aging resistance, oxidation resistance, high resistance to discoloration, high resistance to yellowing, and excellent resistance to cracking; Use water-based topcoats with thinner film thickness, no or less rigid carbon-carbon double bond structure of benzene rings, and better aging resistance to replace UV topcoats with thicker film thickness, rich in rigid carbon-carbon double bond structure of benzene rings (aromatic rings), and poor aging resistance. In addition, a large amount of ultraviolet light absorber, anti-light aging and antioxidant additives can be added to the water-based topcoat. While improving the light discoloration, anti-oxidation discoloration and yellowing resistance of the topcoat coating, it will not affect the curing efficiency and odor-free effect of the topcoat, achieving a multi-functional effect of both odor-free and aging resistance; Through the heat treatment in the infrared heating dehumidification tunnel and the heated convection dehumidification vertical baking room for a longer time (1.5~3h) and higher temperature (40~60℃), the small molecular weight and low boiling point VOCs and odor substances in the coating are completely volatilized and released from the surface along with the volatilization and migration of water, and the VOCs and odor substances in the substrate layer are better volatilized and released from the surface and side parts of the board, thereby achieving a better deodorization and VOCs purification effect.

[0091] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features applied for herein.

Claims

1. A three-stage digital painting process for odorless, aging-resistant, and crack-resistant solid wood water-based paint panels, characterized in that: It includes the following steps: S1 section: Primer composite coating: S101, coating of the first primer: after sanding and dust removal on the surface of the substrate, roll-coat the UV odor-free, yellowing-resistant, high-adhesion clear primer and adhesive putty clear primer in sequence; S102, coating of the second primer: roll-coat UV-free, odor-free, yellowing-resistant, white solid color primer on the first primer; S103, coating of the third primer: roll-coat UV odor-free, yellowing-resistant, color-correcting solid-color primer on the second primer; S104, coating of the fourth primer: roll-coat the UV odor-free, yellowing-resistant, color-correcting solid-color primer on the third primer; S2 section: Digital color composite coating: S201, coating of the first intermediate coating: roller-coat UV odor-free, yellowing-resistant, high-adhesion clear primer on the fourth primer coating of S104; S202, coating of the second intermediate coating: spraying UV-clear, highly resistant to discoloration yellow, magenta, cyan, and black solid color inks on the first intermediate coating respectively; S203, coating of the third intermediate coating: roll-coat UV odor-free, yellowing-resistant sanding clear primer or hardened clear primer on the second intermediate coating; S3 section: water paint surface composite coating: S301, coating of the first topcoat: Roller-coat UV odor-free, yellowing-resistant, high-adhesion clear primer on top of the third midcoat; S302, coating of the second topcoat: coating the first topcoat with UV odor-free, yellowing-resistant, synchronous texture clear topcoat by roller coating; S303, coating of the third topcoat: after rolling the water-based UV odor-free, yellowing-resistant, color-correcting and clear primer on the second topcoat, heat and dehumidify and dry at 80-100°C for 2 minutes; S304, coating of the fourth topcoat: spray a water-based, odorless, yellowing-resistant clear topcoat on top of the third topcoat, first dry the surface in an infrared drying tunnel at 35-45°C for 10 minutes, then dry the inner layer in a heated and dehumidified vertical drying room at 45-60°C for 90-120 minutes.

2. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized by: In the S1 section, the coating speed of the primer composite coating is 16~18m / min; In the S2 section, the coating speed of digital color composite coating is 24~26m / min; In the S3 section, the coating speed of the water-based paint surface composite coating is 5~6m / min.

3. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized by: The base material is a hard, encrypted, crack-resistant, closed, real wood veneer, formaldehyde-free, and odor-free artificial board.

4. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized in that: In the S1 section, UV odor-free yellowing-resistant high adhesion clear primer, adhesion putty clear primer, UV odor-free yellowing-resistant white solid color primer, UV odor-free yellowing-resistant color-modifying solid color primer, UV odor-free yellowing-resistant color-modifying solid color primer: The long-lasting anti-yellowing multifunctional additive used is a single crystal rutile type pigment-grade and micron-grade ultrafine particle titanium dioxide with a particle size of 100-400nm. Calculated by weight, the addition amount of the long-lasting anti-yellowing multifunctional additive accounts for 5-8% of the weight of the above-mentioned primers. The UV resin used is aliphatic non-aromatic polyurethane acrylate resin, silicone-modified or polyurethane-modified epoxy acrylic resin, pure acrylic resin, or a mixture thereof. Calculated by weight, the amount of UV resin added accounts for 46-65% of the weight of the above primers; The UV active monomer used is TMPTA trimethylolpropane acrylate, TPGDA tripropylene glycol acrylate, DPGDA dipropylene glycol diacrylate, or a mixture thereof. Calculated by weight, the amount of the UV active monomer added accounts for 25-45% of the weight of the above primers. The photoinitiator used is TPO 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, BMF methyl benzoylformate, ITX isopropylthioxanthone, or a mixture thereof. Calculated by weight, the amount of the photoinitiator added accounts for 2-6% of the weight of the above primers.

5. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized in that: UV clean, highly resistant to discoloration, yellow, magenta, cyan, black solid color inks: The long-lasting anti-yellowing multifunctional additive used is a single crystal rutile type ultrafine particle powder nano titanium dioxide with a particle size of 10-100nm. Calculated by weight, the addition amount of the long-lasting anti-yellowing multifunctional additive accounts for 0.5-5% of the mass of the above-mentioned UV clean odor high color-discoloration-resistant yellow, magenta, cyan, and black solid color inks; The UV resin used is aliphatic non-aromatic polyurethane acrylate resin, fatty acid modified or polyurethane modified or silicone modified epoxy acrylic resin, pure acrylic resin, or a mixture thereof. Calculated by weight, the amount of UV resin added accounts for 30-60% of the mass of UV pure high color fastness yellow, magenta, cyan, black solid color ink; The photoinitiator used is TPO 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, BMF methyl benzoylformate, ITX isopropylthioxanthone, or a mixture thereof. Calculated by weight, the amount of the photoinitiator added accounts for 2-5% of the weight of the above primers.

6. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 5 is characterized by: In fatty acid-modified, polyurethane-modified or silicone-modified epoxy acrylic resins: The preparation method of fatty acid modified epoxy acrylic resin comprises the following steps: 100 parts of bisphenol A epoxy resin and 0.1 parts of hydroquinone were mixed, melted at 90°C, 30 parts of oleic acid were added under stirring, the temperature was raised to 110°C for reaction for 2 hours, the temperature was lowered to 80°C, 25 parts of acrylic acid and 1 part of triethylamine were added dropwise, and the mixture was reacted at 90°C for 3 hours to complete the preparation; The preparation method of polyurethane modified epoxy acrylic resin comprises the following steps: Add 20 parts of hydroxyl-terminated polyurethane prepolymer and 0.2 parts of dibutyltin dilaurate to 100 parts of epoxy acrylic resin heated at 60°C, react for 1.5 hours, then add 3 parts of 1-hydroxy-cyclohexyl-phenyl ketone and 10 parts of tripropylene glycol diacrylate, and stir evenly; The preparation method of organosilicon-modified epoxy acrylic resin comprises the following steps: To 100 parts of epoxy acrylic resin heated at 80°C, add 10 parts of γ-methacryloxypropyltrimethoxysilane, cool to 50°C, add 2 parts of 2-hydroxy-2-methyl-1-phenyl-1-propanone and 10 parts of isooctyl acrylate, and stir well.

7. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized in that: In S302, the UV odorless, yellowing-resistant, synchronously textured clear topcoat includes, by mass, 20-25 parts of polyurethane acrylic resin; 25-40 parts of epoxy acrylic resin; 30-40 parts of an equal mixture of DPGDA dipropylene glycol diacrylate, TPGDA tripropylene glycol acrylate, TMPTA trimethylolpropane acrylate, and HEMA hydroxyethyl methacrylate; 4-7 parts of an equal mixture of MBF, TPO, and ITX; 0.2-0.4 parts of a bubble-breaking polymer solution; and 0.4-0.6 parts of a polysiloxane-ether copolymer solution.

8. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized in that: In S304, the water-based odorless yellowing-resistant clear topcoat includes, by weight: 100 parts of a composition of an aqueous acrylic modified polyurethane resin and an aqueous polyurethane dispersion; 5~15 parts of curing agent; 10~20 parts of diluent; 0.2~2.0 parts of UV absorbers, anti-aging and antioxidant sunscreen additives; 3.0~6.0 parts of VOCs purification and deodorizing agent; 1.0~3.0 parts of additives; The curing agent is a composition of a hydrophilically modified aliphatic polyisocyanate and a hydrophilically modified alicyclic polyisocyanate; The diluent is purified water; The ultraviolet light absorber, anti-aging and antioxidant sunscreen aid is a combination of 2-hydroxy-4-methoxybenzophenone, 4-hydroxy-2,2,6,6-tetramethylpiperidine, diethylaminohydroxybenzoyl hexyl benzoate, ethylhexyl methoxycinnamate, and rutile gas-phase nano titanium dioxide and nano zinc dioxide; The VOCs purification and deodorizing agent is a composition of nano silicon dioxide, nano photocatalyst, chitosan and ethylene urea in equal proportions.

9. The three-stage digital painting process of the odor-free, aging-resistant, and crack-resistant solid wood water-based paint board according to claim 1 is characterized in that: In the S101, the coating amount of UV odor-free, yellowing-resistant, high-adhesion clear primer is 15-25 g / m 2 , the coating amount of adhesive putty clear primer is 25~35g / m 2 , the UVA energy value of UV light radiation is 200~400mJ / cm 2 , UVV energy value is 300~600mJ / cm 2 ; In S102 and S103, the primer coating amount is 20-30 g / m 2 , the UVA energy value of UV light radiation is 150~350mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; In S104, the primer coating amount is 20-30 g / m 2 , the UVA energy value of UV light radiation is 250~400mJ / cm 2 , UVV energy value is 400~600mJ / cm 2 ; In S201, the primer coating amount is 10-20 g / m 2 , the UVA energy value of UV light radiation is 150~300mJ / cm 2 , UVV energy value is 200~400mJ / cm 2 ; In S202, the ink coating amount is 1-10 g / m 2 , the UVA energy value of UV light radiation is 200~400mJ / cm 2 , UVV energy value is 300~600mJ / cm 2 ; In S203, the primer coating amount is 15-25 g / m 2 The UVA energy value in UV light radiation is 300~500 mJ / cm 2 , UVV energy value is 400~800 mJ / cm 2 ; In S301, the primer coating amount is 15-25 g / m 2 , the UVA energy value of UV light radiation is 150~300mJ / cm 2 , UVV energy value is 200~400mJ / cm 2 ; In S302, the topcoat coating amount is 150-250 g / m 2 , the UVA energy value of UV light radiation is 300~400mJ / cm 2 、UVV energy value is 400~600mJ / cm 2 ; In S303, the primer coating amount is 30-45 g / m 2 , the UVA energy value of UV light radiation is 300~400mJ / cm 2 、UVV energy value is 400~600mJ / cm 2 .

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